/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset, **in bytes**, cannot overflow an `isize`.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_offset`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_offset`]: #method.wrapping_offset
+ ///
/// # Examples
///
/// Basic usage:
///
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
- /// In particular, the resulting pointer may *not* be used to access a
- /// different allocated object than the one `self` points to. In other
- /// words, `x.wrapping_offset(y.wrapping_offset_from(x))` is
+ ///
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is
/// *not* the same as `y`, and dereferencing it is undefined behavior
/// unless `x` and `y` point into the same allocated object.
///
- /// Always use `.offset(count)` instead when possible, because `offset`
- /// allows the compiler to optimize better. If you need to cross object
- /// boundaries, cast the pointer to an integer and do the arithmetic there.
+ /// Compared to [`offset`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`offset`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`offset`]: #method.offset
///
/// # Examples
///
/// Behavior:
///
/// * Both the starting and other pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The distance between the pointers, **in bytes**, cannot overflow an `isize`.
///
/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset, **in bytes**, cannot overflow an `isize`.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_add`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_add`]: #method.wrapping_add
+ ///
/// # Examples
///
/// Basic usage:
/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset cannot exceed `isize::MAX` **bytes**.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_sub`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_sub`]: #method.wrapping_sub
+ ///
/// # Examples
///
/// Basic usage:
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
///
- /// Always use `.add(count)` instead when possible, because `add`
- /// allows the compiler to optimize better.
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// Compared to [`add`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`add`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_add` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`add`]: #method.add
///
/// # Examples
///
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
///
- /// Always use `.sub(count)` instead when possible, because `sub`
- /// allows the compiler to optimize better.
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// Compared to [`sub`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`sub`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`sub`]: #method.sub
///
/// # Examples
///
/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset, **in bytes**, cannot overflow an `isize`.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_offset`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_offset`]: #method.wrapping_offset
+ ///
/// # Examples
///
/// Basic usage:
///
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
- /// In particular, the resulting pointer may *not* be used to access a
- /// different allocated object than the one `self` points to. In other
- /// words, `x.wrapping_offset(y.wrapping_offset_from(x))` is
+ ///
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is
/// *not* the same as `y`, and dereferencing it is undefined behavior
/// unless `x` and `y` point into the same allocated object.
///
- /// Always use `.offset(count)` instead when possible, because `offset`
- /// allows the compiler to optimize better. If you need to cross object
- /// boundaries, cast the pointer to an integer and do the arithmetic there.
+ /// Compared to [`offset`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`offset`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`offset`]: #method.offset
///
/// # Examples
///
/// Behavior:
///
/// * Both the starting and other pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The distance between the pointers, **in bytes**, cannot overflow an `isize`.
///
/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset, **in bytes**, cannot overflow an `isize`.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_add`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_add`]: #method.wrapping_add
+ ///
/// # Examples
///
/// Basic usage:
/// Behavior:
///
/// * Both the starting and resulting pointer must be either in bounds or one
- /// byte past the end of the same allocated object.
+ /// byte past the end of the same allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
///
/// * The computed offset cannot exceed `isize::MAX` **bytes**.
///
/// Extension. As such, memory acquired directly from allocators or memory
/// mapped files *may* be too large to handle with this function.
///
- /// Consider using `wrapping_offset` instead if these constraints are
+ /// Consider using [`wrapping_sub`] instead if these constraints are
/// difficult to satisfy. The only advantage of this method is that it
/// enables more aggressive compiler optimizations.
///
+ /// [`wrapping_sub`]: #method.wrapping_sub
+ ///
/// # Examples
///
/// Basic usage:
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
///
- /// Always use `.add(count)` instead when possible, because `add`
- /// allows the compiler to optimize better.
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// Compared to [`add`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`add`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_add` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`add`]: #method.add
///
/// # Examples
///
/// The resulting pointer does not need to be in bounds, but it is
/// potentially hazardous to dereference (which requires `unsafe`).
///
- /// Always use `.sub(count)` instead when possible, because `sub`
- /// allows the compiler to optimize better.
+ /// In particular, the resulting pointer remains attached to the same allocated
+ /// object that `self` points to. It may *not* be used to access a
+ /// different allocated object. Note that in Rust,
+ /// every (stack-allocated) variable is considered a separate allocated object.
+ ///
+ /// Compared to [`sub`], this method basically delays the requirement of staying
+ /// within the same allocated object: [`sub`] is immediate Undefined Behavior when
+ /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads
+ /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized
+ /// better and is thus preferrable in performance-sensitive code.
+ ///
+ /// If you need to cross object boundaries, cast the pointer to an integer and
+ /// do the arithmetic there.
+ ///
+ /// [`sub`]: #method.sub
///
/// # Examples
///
use std::borrow::Cow;
use std::hash::Hash;
use std::fmt::Debug;
-use rustc_data_structures::sync::Lock;
+use rustc_data_structures::sharded::Sharded;
use rustc_data_structures::fingerprint::Fingerprint;
use crate::ich::StableHashingContext;
fn query(key: Self::Key) -> Query<'tcx>;
// Don't use this method to access query results, instead use the methods on TyCtxt
- fn query_cache<'a>(tcx: TyCtxt<'tcx>) -> &'a Lock<QueryCache<'tcx, Self>>;
+ fn query_cache<'a>(tcx: TyCtxt<'tcx>) -> &'a Sharded<QueryCache<'tcx, Self>>;
fn to_dep_node(tcx: TyCtxt<'tcx>, key: &Self::Key) -> DepNode;
::std::any::type_name::<Q>());
time_ext(tcx.sess.time_extended(), Some(tcx.sess), desc, || {
- let map = Q::query_cache(tcx).borrow();
- assert!(map.active.is_empty());
- for (key, entry) in map.results.iter() {
+ let shards = Q::query_cache(tcx).lock_shards();
+ assert!(shards.iter().all(|shard| shard.active.is_empty()));
+ for (key, entry) in shards.iter().flat_map(|shard| shard.results.iter()) {
if Q::cache_on_disk(tcx, key.clone(), Some(&entry.value)) {
let dep_node = SerializedDepNodeIndex::new(entry.index.index());
use errors::FatalError;
use rustc_data_structures::fx::{FxHashMap};
use rustc_data_structures::sync::{Lrc, Lock};
+use rustc_data_structures::sharded::Sharded;
use rustc_data_structures::thin_vec::ThinVec;
#[cfg(not(parallel_compiler))]
use rustc_data_structures::cold_path;
/// A type representing the responsibility to execute the job in the `job` field.
/// This will poison the relevant query if dropped.
pub(super) struct JobOwner<'a, 'tcx, Q: QueryDescription<'tcx>> {
- cache: &'a Lock<QueryCache<'tcx, Q>>,
+ cache: &'a Sharded<QueryCache<'tcx, Q>>,
key: Q::Key,
job: Lrc<QueryJob<'tcx>>,
}
pub(super) fn try_get(tcx: TyCtxt<'tcx>, span: Span, key: &Q::Key) -> TryGetJob<'a, 'tcx, Q> {
let cache = Q::query_cache(tcx);
loop {
- let mut lock = cache.borrow_mut();
+ let mut lock = cache.get_shard_by_value(key).lock();
if let Some(value) = lock.results.get(key) {
profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
tcx.sess.profiler(|p| p.record_query_hit(Q::NAME));
let value = QueryValue::new(result.clone(), dep_node_index);
{
- let mut lock = cache.borrow_mut();
+ let mut lock = cache.get_shard_by_value(&key).lock();
lock.active.remove(&key);
lock.results.insert(key, value);
}
#[cold]
fn drop(&mut self) {
// Poison the query so jobs waiting on it panic
- self.cache.borrow_mut().active.insert(self.key.clone(), QueryResult::Poisoned);
+ let shard = self.cache.get_shard_by_value(&self.key);
+ shard.lock().active.insert(self.key.clone(), QueryResult::Poisoned);
// Also signal the completion of the job, so waiters
// will continue execution
self.job.signal_complete();
use std::mem;
#[cfg(parallel_compiler)]
use ty::query::job::QueryResult;
- use rustc_data_structures::sync::Lock;
+ use rustc_data_structures::sharded::Sharded;
use crate::{
rustc_data_structures::stable_hasher::HashStable,
rustc_data_structures::stable_hasher::StableHasherResult,
pub fn collect_active_jobs(&self) -> Vec<Lrc<QueryJob<$tcx>>> {
let mut jobs = Vec::new();
- // We use try_lock here since we are only called from the
+ // We use try_lock_shards here since we are only called from the
// deadlock handler, and this shouldn't be locked.
$(
- jobs.extend(
- self.$name.try_lock().unwrap().active.values().filter_map(|v|
- if let QueryResult::Started(ref job) = *v {
- Some(job.clone())
- } else {
- None
- }
- )
- );
+ let shards = self.$name.try_lock_shards().unwrap();
+ jobs.extend(shards.iter().flat_map(|shard| shard.active.values().filter_map(|v|
+ if let QueryResult::Started(ref job) = *v {
+ Some(job.clone())
+ } else {
+ None
+ }
+ )));
)*
jobs
fn stats<'tcx, Q: QueryConfig<'tcx>>(
name: &'static str,
- map: &QueryCache<'tcx, Q>
+ map: &Sharded<QueryCache<'tcx, Q>>,
) -> QueryStats {
+ let map = map.lock_shards();
QueryStats {
name,
#[cfg(debug_assertions)]
- cache_hits: map.cache_hits,
+ cache_hits: map.iter().map(|shard| shard.cache_hits).sum(),
#[cfg(not(debug_assertions))]
cache_hits: 0,
key_size: mem::size_of::<Q::Key>(),
key_type: type_name::<Q::Key>(),
value_size: mem::size_of::<Q::Value>(),
value_type: type_name::<Q::Value>(),
- entry_count: map.results.len(),
+ entry_count: map.iter().map(|shard| shard.results.len()).sum(),
}
}
$(
queries.push(stats::<queries::$name<'_>>(
stringify!($name),
- &*self.$name.lock()
+ &self.$name,
));
)*
}
#[inline(always)]
- fn query_cache<'a>(tcx: TyCtxt<$tcx>) -> &'a Lock<QueryCache<$tcx, Self>> {
+ fn query_cache<'a>(tcx: TyCtxt<$tcx>) -> &'a Sharded<QueryCache<$tcx, Self>> {
&tcx.queries.$name
}
providers: IndexVec<CrateNum, Providers<$tcx>>,
fallback_extern_providers: Box<Providers<$tcx>>,
- $($(#[$attr])* $name: Lock<QueryCache<$tcx, queries::$name<$tcx>>>,)*
+ $($(#[$attr])* $name: Sharded<QueryCache<$tcx, queries::$name<$tcx>>>,)*
}
};
}
ExprKind::LogicalOp { op, lhs, rhs } => {
// And:
//
- // [block: If(lhs)] -true-> [else_block: dest = (rhs)]
- // | (false)
- // [shortcurcuit_block: dest = false]
+ // [block: If(lhs)] -true-> [else_block: If(rhs)] -true-> [true_block]
+ // | | (false)
+ // +----------false-----------+------------------> [false_block]
//
// Or:
//
- // [block: If(lhs)] -false-> [else_block: dest = (rhs)]
- // | (true)
- // [shortcurcuit_block: dest = true]
+ // [block: If(lhs)] -false-> [else_block: If(rhs)] -true-> [true_block]
+ // | (true) | (false)
+ // [true_block] [false_block]
- let (shortcircuit_block, mut else_block, join_block) = (
+ let (true_block, false_block, mut else_block, join_block) = (
+ this.cfg.start_new_block(),
this.cfg.start_new_block(),
this.cfg.start_new_block(),
this.cfg.start_new_block(),
let lhs = unpack!(block = this.as_local_operand(block, lhs));
let blocks = match op {
- LogicalOp::And => (else_block, shortcircuit_block),
- LogicalOp::Or => (shortcircuit_block, else_block),
+ LogicalOp::And => (else_block, false_block),
+ LogicalOp::Or => (true_block, else_block),
};
let term = TerminatorKind::if_(this.hir.tcx(), lhs, blocks.0, blocks.1);
this.cfg.terminate(block, source_info, term);
+ let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
+ let term = TerminatorKind::if_(this.hir.tcx(), rhs, true_block, false_block);
+ this.cfg.terminate(else_block, source_info, term);
+
this.cfg.push_assign_constant(
- shortcircuit_block,
+ true_block,
source_info,
destination,
Constant {
span: expr_span,
ty: this.hir.bool_ty(),
user_ty: None,
- literal: match op {
- LogicalOp::And => this.hir.false_literal(),
- LogicalOp::Or => this.hir.true_literal(),
- },
+ literal: this.hir.true_literal(),
},
);
- this.cfg.terminate(
- shortcircuit_block,
+
+ this.cfg.push_assign_constant(
+ false_block,
source_info,
- TerminatorKind::Goto { target: join_block },
+ destination,
+ Constant {
+ span: expr_span,
+ ty: this.hir.bool_ty(),
+ user_ty: None,
+ literal: this.hir.false_literal(),
+ },
);
- let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
- this.cfg.push_assign(
- else_block,
+ this.cfg.terminate(
+ true_block,
source_info,
- destination,
- Rvalue::Use(rhs),
+ TerminatorKind::Goto { target: join_block },
);
this.cfg.terminate(
- else_block,
+ false_block,
source_info,
TerminatorKind::Goto { target: join_block },
);
};
if let Some(id) = self.definitions.as_local_node_id(def_id) {
self.local_macro_def_scopes[&id]
- } else if self.is_builtin_macro(Some(def_id)) {
- self.injected_crate.unwrap_or(self.graph_root)
} else {
let module_def_id = ty::DefIdTree::parent(&*self, def_id).unwrap();
self.get_module(module_def_id)
};
self.r.populate_module_if_necessary(module);
- if let Some(name) = self.r.session.parse_sess.injected_crate_name.try_get() {
- if name.as_str() == ident.name.as_str() {
- self.r.injected_crate = Some(module);
- }
- }
let used = self.process_legacy_macro_imports(item, module);
let binding =
use crate::resolve_imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
use crate::{path_names_to_string, KNOWN_TOOLS};
-use crate::{CrateLint, LegacyScope, Module, ModuleOrUniformRoot};
+use crate::{BindingError, CrateLint, LegacyScope, Module, ModuleOrUniformRoot};
use crate::{PathResult, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Segment};
type Res = def::Res<ast::NodeId>;
err
}
ResolutionError::VariableNotBoundInPattern(binding_error) => {
- let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
+ let BindingError { name, target, origin, could_be_path } = binding_error;
+
+ let target_sp = target.iter().copied().collect::<Vec<_>>();
+ let origin_sp = origin.iter().copied().collect::<Vec<_>>();
+
let msp = MultiSpan::from_spans(target_sp.clone());
- let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
+ let msg = format!("variable `{}` is not bound in all patterns", name);
let mut err = self.session.struct_span_err_with_code(
msp,
&msg,
DiagnosticId::Error("E0408".into()),
);
for sp in target_sp {
- err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
+ err.span_label(sp, format!("pattern doesn't bind `{}`", name));
}
- let origin_sp = binding_error.origin.iter().cloned();
for sp in origin_sp {
err.span_label(sp, "variable not in all patterns");
}
+ if *could_be_path {
+ let help_msg = format!(
+ "if you meant to match on a variant or a `const` item, consider \
+ making the path in the pattern qualified: `?::{}`",
+ name,
+ );
+ err.span_help(span, &help_msg);
+ }
err
}
ResolutionError::VariableBoundWithDifferentMode(variable_name,
// Checks that all of the arms in an or-pattern have exactly the
// same set of bindings, with the same binding modes for each.
fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
- if pats.is_empty() {
- return;
- }
-
let mut missing_vars = FxHashMap::default();
let mut inconsistent_vars = FxHashMap::default();
- for (i, p) in pats.iter().enumerate() {
- let map_i = self.binding_mode_map(&p);
-
- for (j, q) in pats.iter().enumerate() {
- if i == j {
- continue;
- }
- let map_j = self.binding_mode_map(&q);
- for (&key, &binding_i) in &map_i {
- if map_j.is_empty() { // Account for missing bindings when
- let binding_error = missing_vars // `map_j` has none.
- .entry(key.name)
- .or_insert(BindingError {
- name: key.name,
- origin: BTreeSet::new(),
- target: BTreeSet::new(),
- });
- binding_error.origin.insert(binding_i.span);
- binding_error.target.insert(q.span);
- }
- for (&key_j, &binding_j) in &map_j {
- match map_i.get(&key_j) {
- None => { // missing binding
- let binding_error = missing_vars
- .entry(key_j.name)
- .or_insert(BindingError {
- name: key_j.name,
- origin: BTreeSet::new(),
- target: BTreeSet::new(),
- });
- binding_error.origin.insert(binding_j.span);
- binding_error.target.insert(p.span);
- }
- Some(binding_i) => { // check consistent binding
- if binding_i.binding_mode != binding_j.binding_mode {
- inconsistent_vars
- .entry(key.name)
- .or_insert((binding_j.span, binding_i.span));
- }
+ for pat_outer in pats.iter() {
+ let map_outer = self.binding_mode_map(&pat_outer);
+
+ for pat_inner in pats.iter().filter(|pat| pat.id != pat_outer.id) {
+ let map_inner = self.binding_mode_map(&pat_inner);
+
+ for (&key_inner, &binding_inner) in map_inner.iter() {
+ match map_outer.get(&key_inner) {
+ None => { // missing binding
+ let binding_error = missing_vars
+ .entry(key_inner.name)
+ .or_insert(BindingError {
+ name: key_inner.name,
+ origin: BTreeSet::new(),
+ target: BTreeSet::new(),
+ could_be_path:
+ key_inner.name.as_str().starts_with(char::is_uppercase)
+ });
+ binding_error.origin.insert(binding_inner.span);
+ binding_error.target.insert(pat_outer.span);
+ }
+ Some(binding_outer) => { // check consistent binding
+ if binding_outer.binding_mode != binding_inner.binding_mode {
+ inconsistent_vars
+ .entry(key_inner.name)
+ .or_insert((binding_inner.span, binding_outer.span));
}
}
}
}
}
}
- let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
+
+ let mut missing_vars = missing_vars.iter_mut().collect::<Vec<_>>();
missing_vars.sort();
- for (_, v) in missing_vars {
+ for (name, mut v) in missing_vars {
+ if inconsistent_vars.contains_key(name) {
+ v.could_be_path = false;
+ }
self.r.report_error(
- *v.origin.iter().next().unwrap(), ResolutionError::VariableNotBoundInPattern(v)
- );
+ *v.origin.iter().next().unwrap(),
+ ResolutionError::VariableNotBoundInPattern(v));
}
+
let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
inconsistent_vars.sort();
for (name, v) in inconsistent_vars {
self.resolve_pattern(pat, source, &mut bindings_list);
}
// This has to happen *after* we determine which pat_idents are variants
- self.check_consistent_bindings(pats);
+ if pats.len() > 1 {
+ self.check_consistent_bindings(pats);
+ }
}
fn resolve_block(&mut self, block: &Block) {
name: Name,
origin: BTreeSet<Span>,
target: BTreeSet<Span>,
+ could_be_path: bool
}
impl PartialOrd for BindingError {
/// it's not used during normal resolution, only for better error reporting.
struct_constructors: DefIdMap<(Res, ty::Visibility)>,
- injected_crate: Option<Module<'a>>,
-
/// Features enabled for this crate.
active_features: FxHashSet<Symbol>,
}
unused_macros: Default::default(),
proc_macro_stubs: Default::default(),
special_derives: Default::default(),
- injected_crate: None,
active_features:
features.declared_lib_features.iter().map(|(feat, ..)| *feat)
.chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
if ext.is_builtin {
// The macro is a built-in, replace only the expander function.
result.kind = ext.kind;
- // Also reset its edition to the global one for compatibility.
- result.edition = self.session.edition();
} else {
// The macro is from a plugin, the in-source definition is dummy,
// take all the data from the resolver.
/// * Environment variable is not present
/// * Environment variable is not valid unicode
///
+/// # Panics
+///
+/// This function may panic if `key` is empty, contains an ASCII equals sign
+/// `'='` or the NUL character `'\0'`, or when the value contains the NUL
+/// character.
+///
/// # Examples
///
/// ```
///
/// [`None`]: ../option/enum.Option.html#variant.None
///
+/// # Panics
+///
+/// This function may panic if `key` is empty, contains an ASCII equals sign
+/// `'='` or the NUL character `'\0'`, or when the value contains the NUL
+/// character.
+///
/// # Examples
///
/// ```
pub helper_attrs: Vec<Symbol>,
/// Edition of the crate in which this macro is defined.
pub edition: Edition,
- /// Built-in macros have a couple of special properties (meaning of `$crate`,
- /// availability in `#[no_implicit_prelude]` modules), so we have to keep this flag.
+ /// Built-in macros have a couple of special properties like availability
+ /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
pub is_builtin: bool,
/// We have to identify macros providing a `Copy` impl early for compatibility reasons.
pub is_derive_copy: bool,
let expr_loc_ptr = self.expr_addr_of(span, expr_loc_tuple);
self.expr_call_global(
span,
- self.std_path(&[sym::rt, sym::begin_panic]),
+ [sym::std, sym::rt, sym::begin_panic].iter().map(|s| Ident::new(*s, span)).collect(),
vec![
self.expr_str(span, msg),
expr_loc_ptr])
-// ignore-tidy-filelength
-
-use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy};
-use crate::ast::{GenericBound, TraitBoundModifier};
-use crate::ast::Unsafety;
-use crate::ast::{Mod, AnonConst, Arg, Arm, Attribute, BindingMode, TraitItemKind};
-use crate::ast::Block;
-use crate::ast::{BlockCheckMode, CaptureBy, Movability};
-use crate::ast::{Constness, Crate};
-use crate::ast::Defaultness;
-use crate::ast::EnumDef;
-use crate::ast::{Expr, ExprKind, RangeLimits};
-use crate::ast::{Field, FnDecl, FnHeader};
-use crate::ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
-use crate::ast::{GenericParam, GenericParamKind};
-use crate::ast::GenericArg;
-use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind};
-use crate::ast::{Label, Lifetime};
-use crate::ast::Local;
-use crate::ast::MacStmtStyle;
-use crate::ast::{Mac, Mac_, MacDelimiter};
-use crate::ast::{MutTy, Mutability};
-use crate::ast::{Pat, PatKind, PathSegment};
-use crate::ast::{PolyTraitRef, QSelf};
-use crate::ast::{Stmt, StmtKind};
-use crate::ast::{VariantData, StructField};
-use crate::ast::StrStyle;
-use crate::ast::SelfKind;
-use crate::ast::{TraitItem, TraitRef, TraitObjectSyntax};
-use crate::ast::{Ty, TyKind, AssocTyConstraint, AssocTyConstraintKind, GenericBounds};
-use crate::ast::{Visibility, VisibilityKind, WhereClause, CrateSugar};
-use crate::ast::{UseTree, UseTreeKind};
-use crate::ast::{BinOpKind, UnOp};
-use crate::ast::{RangeEnd, RangeSyntax};
-use crate::{ast, attr};
-use crate::ext::base::DummyResult;
+mod expr;
+mod pat;
+mod item;
+pub use item::AliasKind;
+mod module;
+pub use module::{ModulePath, ModulePathSuccess};
+mod ty;
+mod path;
+pub use path::PathStyle;
+mod stmt;
+mod generics;
+
+use crate::ast::{self, AttrStyle, Attribute, Arg, BindingMode, StrStyle, SelfKind};
+use crate::ast::{FnDecl, Ident, IsAsync, MacDelimiter, Mutability, TyKind};
+use crate::ast::{Visibility, VisibilityKind, Unsafety, CrateSugar};
use crate::ext::hygiene::SyntaxContext;
-use crate::source_map::{self, SourceMap, Spanned, respan};
-use crate::parse::{SeqSep, classify, literal, token};
+use crate::source_map::{self, respan};
+use crate::parse::{SeqSep, literal, token};
use crate::parse::lexer::UnmatchedBrace;
use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
use crate::parse::token::{Token, TokenKind, DelimToken};
-use crate::parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership};
-use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par};
+use crate::parse::{ParseSess, Directory, DirectoryOwnership};
use crate::print::pprust;
use crate::ptr::P;
use crate::parse::PResult;
use crate::symbol::{kw, sym, Symbol};
use crate::parse::diagnostics::{Error, dummy_arg};
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
+use errors::{Applicability, DiagnosticId, FatalError};
use rustc_target::spec::abi::{self, Abi};
use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
use log::debug;
use std::borrow::Cow;
-use std::cmp;
-use std::mem;
-use std::path::{self, Path, PathBuf};
-use std::slice;
-
-#[derive(Debug)]
-/// Whether the type alias or associated type is a concrete type or an opaque type
-pub enum AliasKind {
- /// Just a new name for the same type
- Weak(P<Ty>),
- /// Only trait impls of the type will be usable, not the actual type itself
- OpaqueTy(GenericBounds),
-}
+use std::{cmp, mem, slice};
+use std::path::PathBuf;
bitflags::bitflags! {
struct Restrictions: u8 {
}
}
-type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute>>);
-
-/// Specifies how to parse a path.
-#[derive(Copy, Clone, PartialEq)]
-pub enum PathStyle {
- /// In some contexts, notably in expressions, paths with generic arguments are ambiguous
- /// with something else. For example, in expressions `segment < ....` can be interpreted
- /// as a comparison and `segment ( ....` can be interpreted as a function call.
- /// In all such contexts the non-path interpretation is preferred by default for practical
- /// reasons, but the path interpretation can be forced by the disambiguator `::`, e.g.
- /// `x<y>` - comparisons, `x::<y>` - unambiguously a path.
- Expr,
- /// In other contexts, notably in types, no ambiguity exists and paths can be written
- /// without the disambiguator, e.g., `x<y>` - unambiguously a path.
- /// Paths with disambiguators are still accepted, `x::<Y>` - unambiguously a path too.
- Type,
- /// A path with generic arguments disallowed, e.g., `foo::bar::Baz`, used in imports,
- /// visibilities or attributes.
- /// Technically, this variant is unnecessary and e.g., `Expr` can be used instead
- /// (paths in "mod" contexts have to be checked later for absence of generic arguments
- /// anyway, due to macros), but it is used to avoid weird suggestions about expected
- /// tokens when something goes wrong.
- Mod,
-}
-
#[derive(Clone, Copy, PartialEq, Debug)]
crate enum SemiColonMode {
Break,
Ignore,
}
-/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
-/// dropped into the token stream, which happens while parsing the result of
-/// macro expansion). Placement of these is not as complex as I feared it would
-/// be. The important thing is to make sure that lookahead doesn't balk at
-/// `token::Interpolated` tokens.
-macro_rules! maybe_whole_expr {
- ($p:expr) => {
- if let token::Interpolated(nt) = &$p.token.kind {
- match &**nt {
- token::NtExpr(e) | token::NtLiteral(e) => {
- let e = e.clone();
- $p.bump();
- return Ok(e);
- }
- token::NtPath(path) => {
- let path = path.clone();
- $p.bump();
- return Ok($p.mk_expr(
- $p.token.span, ExprKind::Path(None, path), ThinVec::new()
- ));
- }
- token::NtBlock(block) => {
- let block = block.clone();
- $p.bump();
- return Ok($p.mk_expr(
- $p.token.span, ExprKind::Block(block, None), ThinVec::new()
- ));
- }
- // N.B: `NtIdent(ident)` is normalized to `Ident` in `fn bump`.
- _ => {},
- };
- }
- }
-}
-
/// As maybe_whole_expr, but for things other than expressions
+#[macro_export]
macro_rules! maybe_whole {
($p:expr, $constructor:ident, |$x:ident| $e:expr) => {
if let token::Interpolated(nt) = &$p.token.kind {
}
/// If the next tokens are ill-formed `$ty::` recover them as `<$ty>::`.
+#[macro_export]
macro_rules! maybe_recover_from_interpolated_ty_qpath {
($self: expr, $allow_qpath_recovery: expr) => {
if $allow_qpath_recovery && $self.look_ahead(1, |t| t == &token::ModSep) {
}
}
-/// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
-/// `IDENT<<u8 as Trait>::AssocTy>`.
-///
-/// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes
-/// that `IDENT` is not the ident of a fn trait.
-fn can_continue_type_after_non_fn_ident(t: &Token) -> bool {
- t == &token::ModSep || t == &token::Lt ||
- t == &token::BinOp(token::Shl)
-}
-
-/// Information about the path to a module.
-pub struct ModulePath {
- name: String,
- path_exists: bool,
- pub result: Result<ModulePathSuccess, Error>,
-}
-
-pub struct ModulePathSuccess {
- pub path: PathBuf,
- pub directory_ownership: DirectoryOwnership,
- warn: bool,
-}
-
-#[derive(Debug)]
-enum LhsExpr {
- NotYetParsed,
- AttributesParsed(ThinVec<Attribute>),
- AlreadyParsed(P<Expr>),
-}
-
-impl From<Option<ThinVec<Attribute>>> for LhsExpr {
- fn from(o: Option<ThinVec<Attribute>>) -> Self {
- if let Some(attrs) = o {
- LhsExpr::AttributesParsed(attrs)
- } else {
- LhsExpr::NotYetParsed
- }
- }
-}
-
-impl From<P<Expr>> for LhsExpr {
- fn from(expr: P<Expr>) -> Self {
- LhsExpr::AlreadyParsed(expr)
- }
-}
-
#[derive(Copy, Clone, Debug)]
crate enum TokenExpectType {
Expect,
}
}
- /// Returns the span of expr, if it was not interpolated or the span of the interpolated token.
- fn interpolated_or_expr_span(
- &self,
- expr: PResult<'a, P<Expr>>,
- ) -> PResult<'a, (Span, P<Expr>)> {
- expr.map(|e| {
- if self.prev_token_kind == PrevTokenKind::Interpolated {
- (self.prev_span, e)
- } else {
- (e.span, e)
- }
- })
- }
-
pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> {
self.parse_ident_common(true)
}
}
}
-
/// Checks to see if the next token is either `+` or `+=`.
/// Otherwise returns `false`.
fn check_plus(&mut self) -> bool {
self.look_ahead(dist, |t| kws.iter().any(|&kw| t.is_keyword(kw)))
}
- /// Is the current token one of the keywords that signals a bare function type?
- fn token_is_bare_fn_keyword(&mut self) -> bool {
- self.check_keyword(kw::Fn) ||
- self.check_keyword(kw::Unsafe) ||
- self.check_keyword(kw::Extern)
- }
-
- /// Parses a `TyKind::BareFn` type.
- fn parse_ty_bare_fn(&mut self, generic_params: Vec<GenericParam>) -> PResult<'a, TyKind> {
- /*
-
- [unsafe] [extern "ABI"] fn (S) -> T
- ^~~~^ ^~~~^ ^~^ ^
- | | | |
- | | | Return type
- | | Argument types
- | |
- | ABI
- Function Style
- */
-
- let unsafety = self.parse_unsafety();
- let abi = if self.eat_keyword(kw::Extern) {
- self.parse_opt_abi()?.unwrap_or(Abi::C)
- } else {
- Abi::Rust
- };
-
- self.expect_keyword(kw::Fn)?;
- let (inputs, c_variadic) = self.parse_fn_args(false, true)?;
- let ret_ty = self.parse_ret_ty(false)?;
- let decl = P(FnDecl {
- inputs,
- output: ret_ty,
- c_variadic,
- });
- Ok(TyKind::BareFn(P(BareFnTy {
- abi,
- unsafety,
- generic_params,
- decl,
- })))
- }
-
/// Parses asyncness: `async` or nothing.
fn parse_asyncness(&mut self) -> IsAsync {
if self.eat_keyword(kw::Async) {
}
}
- /// Parses the items in a trait declaration.
- pub fn parse_trait_item(&mut self, at_end: &mut bool) -> PResult<'a, TraitItem> {
- maybe_whole!(self, NtTraitItem, |x| x);
- let attrs = self.parse_outer_attributes()?;
- let mut unclosed_delims = vec![];
- let (mut item, tokens) = self.collect_tokens(|this| {
- let item = this.parse_trait_item_(at_end, attrs);
- unclosed_delims.append(&mut this.unclosed_delims);
- item
- })?;
- self.unclosed_delims.append(&mut unclosed_delims);
- // See `parse_item` for why this clause is here.
- if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
- item.tokens = Some(tokens);
- }
- Ok(item)
- }
-
- fn parse_trait_item_(&mut self,
- at_end: &mut bool,
- mut attrs: Vec<Attribute>) -> PResult<'a, TraitItem> {
- let lo = self.token.span;
- self.eat_bad_pub();
- let (name, node, generics) = if self.eat_keyword(kw::Type) {
- self.parse_trait_item_assoc_ty()?
- } else if self.is_const_item() {
- self.expect_keyword(kw::Const)?;
- let ident = self.parse_ident()?;
- self.expect(&token::Colon)?;
- let ty = self.parse_ty()?;
- let default = if self.eat(&token::Eq) {
- let expr = self.parse_expr()?;
- self.expect(&token::Semi)?;
- Some(expr)
- } else {
- self.expect(&token::Semi)?;
- None
- };
- (ident, TraitItemKind::Const(ty, default), ast::Generics::default())
- } else if let Some(mac) = self.parse_assoc_macro_invoc("trait", None, &mut false)? {
- // trait item macro.
- (Ident::invalid(), ast::TraitItemKind::Macro(mac), ast::Generics::default())
- } else {
- let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
-
- let ident = self.parse_ident()?;
- let mut generics = self.parse_generics()?;
-
- let decl = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| {
- // This is somewhat dubious; We don't want to allow
- // argument names to be left off if there is a
- // definition...
-
- // We don't allow argument names to be left off in edition 2018.
- let is_name_required = p.token.span.rust_2018();
- p.parse_arg_general(true, false, |_| is_name_required)
- })?;
- generics.where_clause = self.parse_where_clause()?;
-
- let sig = ast::MethodSig {
- header: FnHeader {
- unsafety,
- constness,
- abi,
- asyncness,
- },
- decl,
- };
-
- let body = match self.token.kind {
- token::Semi => {
- self.bump();
- *at_end = true;
- debug!("parse_trait_methods(): parsing required method");
- None
- }
- token::OpenDelim(token::Brace) => {
- debug!("parse_trait_methods(): parsing provided method");
- *at_end = true;
- let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(inner_attrs.iter().cloned());
- Some(body)
- }
- token::Interpolated(ref nt) => {
- match **nt {
- token::NtBlock(..) => {
- *at_end = true;
- let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(inner_attrs.iter().cloned());
- Some(body)
- }
- _ => {
- return self.expected_semi_or_open_brace();
- }
- }
- }
- _ => {
- return self.expected_semi_or_open_brace();
- }
- };
- (ident, ast::TraitItemKind::Method(sig, body), generics)
- };
-
- Ok(TraitItem {
- id: ast::DUMMY_NODE_ID,
- ident: name,
- attrs,
- generics,
- node,
- span: lo.to(self.prev_span),
- tokens: None,
- })
- }
-
- /// Parses an optional return type `[ -> TY ]` in a function declaration.
- fn parse_ret_ty(&mut self, allow_plus: bool) -> PResult<'a, FunctionRetTy> {
- if self.eat(&token::RArrow) {
- Ok(FunctionRetTy::Ty(self.parse_ty_common(allow_plus, true, false)?))
- } else {
- Ok(FunctionRetTy::Default(self.token.span.shrink_to_lo()))
- }
- }
-
- /// Parses a type.
- pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
- self.parse_ty_common(true, true, false)
- }
-
- /// Parses a type in restricted contexts where `+` is not permitted.
- ///
- /// Example 1: `&'a TYPE`
- /// `+` is prohibited to maintain operator priority (P(+) < P(&)).
- /// Example 2: `value1 as TYPE + value2`
- /// `+` is prohibited to avoid interactions with expression grammar.
- fn parse_ty_no_plus(&mut self) -> PResult<'a, P<Ty>> {
- self.parse_ty_common(false, true, false)
- }
-
- fn parse_ty_common(&mut self, allow_plus: bool, allow_qpath_recovery: bool,
- allow_c_variadic: bool) -> PResult<'a, P<Ty>> {
- maybe_recover_from_interpolated_ty_qpath!(self, allow_qpath_recovery);
- maybe_whole!(self, NtTy, |x| x);
-
- let lo = self.token.span;
- let mut impl_dyn_multi = false;
- let node = if self.eat(&token::OpenDelim(token::Paren)) {
- // `(TYPE)` is a parenthesized type.
- // `(TYPE,)` is a tuple with a single field of type TYPE.
- let mut ts = vec![];
- let mut last_comma = false;
- while self.token != token::CloseDelim(token::Paren) {
- ts.push(self.parse_ty()?);
- if self.eat(&token::Comma) {
- last_comma = true;
- } else {
- last_comma = false;
- break;
- }
- }
- let trailing_plus = self.prev_token_kind == PrevTokenKind::Plus;
- self.expect(&token::CloseDelim(token::Paren))?;
-
- if ts.len() == 1 && !last_comma {
- let ty = ts.into_iter().nth(0).unwrap().into_inner();
- let maybe_bounds = allow_plus && self.token.is_like_plus();
- match ty.node {
- // `(TY_BOUND_NOPAREN) + BOUND + ...`.
- TyKind::Path(None, ref path) if maybe_bounds => {
- self.parse_remaining_bounds(Vec::new(), path.clone(), lo, true)?
- }
- TyKind::TraitObject(ref bounds, TraitObjectSyntax::None)
- if maybe_bounds && bounds.len() == 1 && !trailing_plus => {
- let path = match bounds[0] {
- GenericBound::Trait(ref pt, ..) => pt.trait_ref.path.clone(),
- GenericBound::Outlives(..) => self.bug("unexpected lifetime bound"),
- };
- self.parse_remaining_bounds(Vec::new(), path, lo, true)?
- }
- // `(TYPE)`
- _ => TyKind::Paren(P(ty))
- }
- } else {
- TyKind::Tup(ts)
- }
- } else if self.eat(&token::Not) {
- // Never type `!`
- TyKind::Never
- } else if self.eat(&token::BinOp(token::Star)) {
- // Raw pointer
- TyKind::Ptr(self.parse_ptr()?)
- } else if self.eat(&token::OpenDelim(token::Bracket)) {
- // Array or slice
- let t = self.parse_ty()?;
- // Parse optional `; EXPR` in `[TYPE; EXPR]`
- let t = match self.maybe_parse_fixed_length_of_vec()? {
- None => TyKind::Slice(t),
- Some(length) => TyKind::Array(t, AnonConst {
- id: ast::DUMMY_NODE_ID,
- value: length,
- }),
- };
- self.expect(&token::CloseDelim(token::Bracket))?;
- t
- } else if self.check(&token::BinOp(token::And)) || self.check(&token::AndAnd) {
- // Reference
- self.expect_and()?;
- self.parse_borrowed_pointee()?
- } else if self.eat_keyword_noexpect(kw::Typeof) {
- // `typeof(EXPR)`
- // In order to not be ambiguous, the type must be surrounded by parens.
- self.expect(&token::OpenDelim(token::Paren))?;
- let e = AnonConst {
- id: ast::DUMMY_NODE_ID,
- value: self.parse_expr()?,
- };
- self.expect(&token::CloseDelim(token::Paren))?;
- TyKind::Typeof(e)
- } else if self.eat_keyword(kw::Underscore) {
- // A type to be inferred `_`
- TyKind::Infer
- } else if self.token_is_bare_fn_keyword() {
- // Function pointer type
- self.parse_ty_bare_fn(Vec::new())?
- } else if self.check_keyword(kw::For) {
- // Function pointer type or bound list (trait object type) starting with a poly-trait.
- // `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T`
- // `for<'lt> Trait1<'lt> + Trait2 + 'a`
- let lo = self.token.span;
- let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
- if self.token_is_bare_fn_keyword() {
- self.parse_ty_bare_fn(lifetime_defs)?
- } else {
- let path = self.parse_path(PathStyle::Type)?;
- let parse_plus = allow_plus && self.check_plus();
- self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)?
- }
- } else if self.eat_keyword(kw::Impl) {
- // Always parse bounds greedily for better error recovery.
- let bounds = self.parse_generic_bounds(None)?;
- impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
- TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)
- } else if self.check_keyword(kw::Dyn) &&
- (self.token.span.rust_2018() ||
- self.look_ahead(1, |t| t.can_begin_bound() &&
- !can_continue_type_after_non_fn_ident(t))) {
- self.bump(); // `dyn`
- // Always parse bounds greedily for better error recovery.
- let bounds = self.parse_generic_bounds(None)?;
- impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
- TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn)
- } else if self.check(&token::Question) ||
- self.check_lifetime() && self.look_ahead(1, |t| t.is_like_plus()) {
- // Bound list (trait object type)
- TyKind::TraitObject(self.parse_generic_bounds_common(allow_plus, None)?,
- TraitObjectSyntax::None)
- } else if self.eat_lt() {
- // Qualified path
- let (qself, path) = self.parse_qpath(PathStyle::Type)?;
- TyKind::Path(Some(qself), path)
- } else if self.token.is_path_start() {
- // Simple path
- let path = self.parse_path(PathStyle::Type)?;
- if self.eat(&token::Not) {
- // Macro invocation in type position
- let (delim, tts) = self.expect_delimited_token_tree()?;
- let node = Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- };
- TyKind::Mac(respan(lo.to(self.prev_span), node))
- } else {
- // Just a type path or bound list (trait object type) starting with a trait.
- // `Type`
- // `Trait1 + Trait2 + 'a`
- if allow_plus && self.check_plus() {
- self.parse_remaining_bounds(Vec::new(), path, lo, true)?
- } else {
- TyKind::Path(None, path)
- }
- }
- } else if self.check(&token::DotDotDot) {
- if allow_c_variadic {
- self.eat(&token::DotDotDot);
- TyKind::CVarArgs
- } else {
- return Err(self.fatal(
- "only foreign functions are allowed to be C-variadic"
- ));
- }
- } else {
- let msg = format!("expected type, found {}", self.this_token_descr());
- let mut err = self.fatal(&msg);
- err.span_label(self.token.span, "expected type");
- self.maybe_annotate_with_ascription(&mut err, true);
- return Err(err);
- };
-
- let span = lo.to(self.prev_span);
- let ty = P(Ty { node, span, id: ast::DUMMY_NODE_ID });
-
- // Try to recover from use of `+` with incorrect priority.
- self.maybe_report_ambiguous_plus(allow_plus, impl_dyn_multi, &ty);
- self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?;
- self.maybe_recover_from_bad_qpath(ty, allow_qpath_recovery)
- }
-
- fn parse_remaining_bounds(&mut self, generic_params: Vec<GenericParam>, path: ast::Path,
- lo: Span, parse_plus: bool) -> PResult<'a, TyKind> {
- let poly_trait_ref = PolyTraitRef::new(generic_params, path, lo.to(self.prev_span));
- let mut bounds = vec![GenericBound::Trait(poly_trait_ref, TraitBoundModifier::None)];
- if parse_plus {
- self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded
- bounds.append(&mut self.parse_generic_bounds(Some(self.prev_span))?);
- }
- Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None))
- }
-
- fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> {
- let opt_lifetime = if self.check_lifetime() { Some(self.expect_lifetime()) } else { None };
- let mutbl = self.parse_mutability();
- let ty = self.parse_ty_no_plus()?;
- return Ok(TyKind::Rptr(opt_lifetime, MutTy { ty, mutbl }));
- }
-
- fn parse_ptr(&mut self) -> PResult<'a, MutTy> {
- let mutbl = if self.eat_keyword(kw::Mut) {
- Mutability::Mutable
- } else if self.eat_keyword(kw::Const) {
- Mutability::Immutable
- } else {
- let span = self.prev_span;
- let msg = "expected mut or const in raw pointer type";
- self.struct_span_err(span, msg)
- .span_label(span, msg)
- .help("use `*mut T` or `*const T` as appropriate")
- .emit();
- Mutability::Immutable
- };
- let t = self.parse_ty_no_plus()?;
- Ok(MutTy { ty: t, mutbl })
- }
-
fn is_named_argument(&self) -> bool {
let offset = match self.token.kind {
token::Interpolated(ref nt) => match **nt {
match ty {
Ok(ty) => {
let ident = Ident::new(kw::Invalid, self.prev_span);
- let pat = P(Pat {
- id: ast::DUMMY_NODE_ID,
- node: PatKind::Ident(
- BindingMode::ByValue(Mutability::Immutable), ident, None),
- span: ty.span,
- });
+ let bm = BindingMode::ByValue(Mutability::Immutable);
+ let pat = self.mk_pat_ident(ty.span, bm, ident);
(pat, ty)
}
Err(mut err) => {
Ok(Arg { attrs: attrs.into(), id: ast::DUMMY_NODE_ID, pat, span, ty })
}
- /// Parses an argument in a lambda header (e.g., `|arg, arg|`).
- fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
- let lo = self.token.span;
- let attrs = self.parse_arg_attributes()?;
- let pat = self.parse_pat(Some("argument name"))?;
- let t = if self.eat(&token::Colon) {
- self.parse_ty()?
- } else {
- P(Ty {
- id: ast::DUMMY_NODE_ID,
- node: TyKind::Infer,
- span: self.prev_span,
- })
- };
- let span = lo.to(self.token.span);
- Ok(Arg {
- attrs: attrs.into(),
- ty: t,
- pat,
- span,
- id: ast::DUMMY_NODE_ID
- })
- }
-
- fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<'a, Option<P<ast::Expr>>> {
- if self.eat(&token::Semi) {
- Ok(Some(self.parse_expr()?))
- } else {
- Ok(None)
- }
- }
-
- /// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
- crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
- maybe_whole_expr!(self);
-
- let minus_lo = self.token.span;
- let minus_present = self.eat(&token::BinOp(token::Minus));
- let lo = self.token.span;
- let literal = self.parse_lit()?;
- let hi = self.prev_span;
- let expr = self.mk_expr(lo.to(hi), ExprKind::Lit(literal), ThinVec::new());
-
- if minus_present {
- let minus_hi = self.prev_span;
- let unary = self.mk_unary(UnOp::Neg, expr);
- Ok(self.mk_expr(minus_lo.to(minus_hi), unary, ThinVec::new()))
- } else {
- Ok(expr)
- }
- }
-
- fn parse_path_segment_ident(&mut self) -> PResult<'a, ast::Ident> {
- match self.token.kind {
- token::Ident(name, _) if name.is_path_segment_keyword() => {
- let span = self.token.span;
- self.bump();
- Ok(Ident::new(name, span))
- }
- _ => self.parse_ident(),
- }
- }
-
- fn parse_ident_or_underscore(&mut self) -> PResult<'a, ast::Ident> {
- match self.token.kind {
- token::Ident(name, false) if name == kw::Underscore => {
- let span = self.token.span;
- self.bump();
- Ok(Ident::new(name, span))
- }
- _ => self.parse_ident(),
- }
- }
-
- /// Parses a qualified path.
- /// Assumes that the leading `<` has been parsed already.
- ///
- /// `qualified_path = <type [as trait_ref]>::path`
- ///
- /// # Examples
- /// `<T>::default`
- /// `<T as U>::a`
- /// `<T as U>::F::a<S>` (without disambiguator)
- /// `<T as U>::F::a::<S>` (with disambiguator)
- fn parse_qpath(&mut self, style: PathStyle) -> PResult<'a, (QSelf, ast::Path)> {
- let lo = self.prev_span;
- let ty = self.parse_ty()?;
-
- // `path` will contain the prefix of the path up to the `>`,
- // if any (e.g., `U` in the `<T as U>::*` examples
- // above). `path_span` has the span of that path, or an empty
- // span in the case of something like `<T>::Bar`.
- let (mut path, path_span);
- if self.eat_keyword(kw::As) {
- let path_lo = self.token.span;
- path = self.parse_path(PathStyle::Type)?;
- path_span = path_lo.to(self.prev_span);
- } else {
- path_span = self.token.span.to(self.token.span);
- path = ast::Path { segments: Vec::new(), span: path_span };
- }
-
- // See doc comment for `unmatched_angle_bracket_count`.
- self.expect(&token::Gt)?;
- if self.unmatched_angle_bracket_count > 0 {
- self.unmatched_angle_bracket_count -= 1;
- debug!("parse_qpath: (decrement) count={:?}", self.unmatched_angle_bracket_count);
- }
-
- self.expect(&token::ModSep)?;
-
- let qself = QSelf { ty, path_span, position: path.segments.len() };
- self.parse_path_segments(&mut path.segments, style)?;
-
- Ok((qself, ast::Path { segments: path.segments, span: lo.to(self.prev_span) }))
- }
-
- /// Parses simple paths.
- ///
- /// `path = [::] segment+`
- /// `segment = ident | ident[::]<args> | ident[::](args) [-> type]`
- ///
- /// # Examples
- /// `a::b::C<D>` (without disambiguator)
- /// `a::b::C::<D>` (with disambiguator)
- /// `Fn(Args)` (without disambiguator)
- /// `Fn::(Args)` (with disambiguator)
- pub fn parse_path(&mut self, style: PathStyle) -> PResult<'a, ast::Path> {
- maybe_whole!(self, NtPath, |path| {
- if style == PathStyle::Mod &&
- path.segments.iter().any(|segment| segment.args.is_some()) {
- self.diagnostic().span_err(path.span, "unexpected generic arguments in path");
- }
- path
- });
-
- let lo = self.meta_var_span.unwrap_or(self.token.span);
- let mut segments = Vec::new();
- let mod_sep_ctxt = self.token.span.ctxt();
- if self.eat(&token::ModSep) {
- segments.push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
- }
- self.parse_path_segments(&mut segments, style)?;
-
- Ok(ast::Path { segments, span: lo.to(self.prev_span) })
- }
-
- /// Like `parse_path`, but also supports parsing `Word` meta items into paths for
- /// backwards-compatibility. This is used when parsing derive macro paths in `#[derive]`
- /// attributes.
- pub fn parse_path_allowing_meta(&mut self, style: PathStyle) -> PResult<'a, ast::Path> {
- let meta_ident = match self.token.kind {
- token::Interpolated(ref nt) => match **nt {
- token::NtMeta(ref meta) => match meta.node {
- ast::MetaItemKind::Word => Some(meta.path.clone()),
- _ => None,
- },
- _ => None,
- },
- _ => None,
- };
- if let Some(path) = meta_ident {
- self.bump();
- return Ok(path);
- }
- self.parse_path(style)
- }
-
- crate fn parse_path_segments(&mut self,
- segments: &mut Vec<PathSegment>,
- style: PathStyle)
- -> PResult<'a, ()> {
- loop {
- let segment = self.parse_path_segment(style)?;
- if style == PathStyle::Expr {
- // In order to check for trailing angle brackets, we must have finished
- // recursing (`parse_path_segment` can indirectly call this function),
- // that is, the next token must be the highlighted part of the below example:
- //
- // `Foo::<Bar as Baz<T>>::Qux`
- // ^ here
- //
- // As opposed to the below highlight (if we had only finished the first
- // recursion):
- //
- // `Foo::<Bar as Baz<T>>::Qux`
- // ^ here
- //
- // `PathStyle::Expr` is only provided at the root invocation and never in
- // `parse_path_segment` to recurse and therefore can be checked to maintain
- // this invariant.
- self.check_trailing_angle_brackets(&segment, token::ModSep);
- }
- segments.push(segment);
-
- if self.is_import_coupler() || !self.eat(&token::ModSep) {
- return Ok(());
- }
- }
- }
-
- fn parse_path_segment(&mut self, style: PathStyle) -> PResult<'a, PathSegment> {
- let ident = self.parse_path_segment_ident()?;
-
- let is_args_start = |token: &Token| match token.kind {
- token::Lt | token::BinOp(token::Shl) | token::OpenDelim(token::Paren)
- | token::LArrow => true,
- _ => false,
- };
- let check_args_start = |this: &mut Self| {
- this.expected_tokens.extend_from_slice(
- &[TokenType::Token(token::Lt), TokenType::Token(token::OpenDelim(token::Paren))]
- );
- is_args_start(&this.token)
- };
-
- Ok(if style == PathStyle::Type && check_args_start(self) ||
- style != PathStyle::Mod && self.check(&token::ModSep)
- && self.look_ahead(1, |t| is_args_start(t)) {
- // We use `style == PathStyle::Expr` to check if this is in a recursion or not. If
- // it isn't, then we reset the unmatched angle bracket count as we're about to start
- // parsing a new path.
- if style == PathStyle::Expr {
- self.unmatched_angle_bracket_count = 0;
- self.max_angle_bracket_count = 0;
- }
-
- // Generic arguments are found - `<`, `(`, `::<` or `::(`.
- self.eat(&token::ModSep);
- let lo = self.token.span;
- let args = if self.eat_lt() {
- // `<'a, T, A = U>`
- let (args, constraints) =
- self.parse_generic_args_with_leaning_angle_bracket_recovery(style, lo)?;
- self.expect_gt()?;
- let span = lo.to(self.prev_span);
- AngleBracketedArgs { args, constraints, span }.into()
- } else {
- // `(T, U) -> R`
- let (inputs, _) = self.parse_paren_comma_seq(|p| p.parse_ty())?;
- let span = lo.to(self.prev_span);
- let output = if self.eat(&token::RArrow) {
- Some(self.parse_ty_common(false, false, false)?)
- } else {
- None
- };
- ParenthesizedArgs { inputs, output, span }.into()
- };
-
- PathSegment { ident, args, id: ast::DUMMY_NODE_ID }
- } else {
- // Generic arguments are not found.
- PathSegment::from_ident(ident)
- })
- }
-
- crate fn check_lifetime(&mut self) -> bool {
- self.expected_tokens.push(TokenType::Lifetime);
- self.token.is_lifetime()
- }
-
- /// Parses a single lifetime `'a` or panics.
- crate fn expect_lifetime(&mut self) -> Lifetime {
- if let Some(ident) = self.token.lifetime() {
- let span = self.token.span;
- self.bump();
- Lifetime { ident: Ident::new(ident.name, span), id: ast::DUMMY_NODE_ID }
- } else {
- self.span_bug(self.token.span, "not a lifetime")
- }
- }
-
- fn eat_label(&mut self) -> Option<Label> {
- if let Some(ident) = self.token.lifetime() {
- let span = self.token.span;
- self.bump();
- Some(Label { ident: Ident::new(ident.name, span) })
- } else {
- None
- }
- }
-
/// Parses mutability (`mut` or nothing).
fn parse_mutability(&mut self) -> Mutability {
if self.eat_keyword(kw::Mut) {
}
}
- /// Parse ident (COLON expr)?
- fn parse_field(&mut self) -> PResult<'a, Field> {
- let attrs = self.parse_outer_attributes()?;
- let lo = self.token.span;
-
- // Check if a colon exists one ahead. This means we're parsing a fieldname.
- let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| {
- t == &token::Colon || t == &token::Eq
- }) {
- let fieldname = self.parse_field_name()?;
-
- // Check for an equals token. This means the source incorrectly attempts to
- // initialize a field with an eq rather than a colon.
- if self.token == token::Eq {
- self.diagnostic()
- .struct_span_err(self.token.span, "expected `:`, found `=`")
- .span_suggestion(
- fieldname.span.shrink_to_hi().to(self.token.span),
- "replace equals symbol with a colon",
- ":".to_string(),
- Applicability::MachineApplicable,
- )
- .emit();
- }
- self.bump(); // `:`
- (fieldname, self.parse_expr()?, false)
- } else {
- let fieldname = self.parse_ident_common(false)?;
-
- // Mimic `x: x` for the `x` field shorthand.
- let path = ast::Path::from_ident(fieldname);
- let expr = self.mk_expr(fieldname.span, ExprKind::Path(None, path), ThinVec::new());
- (fieldname, expr, true)
- };
- Ok(ast::Field {
- ident: fieldname,
- span: lo.to(expr.span),
- expr,
- is_shorthand,
- attrs: attrs.into(),
- })
- }
-
- crate fn mk_expr(&self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> {
- P(Expr { node, span, attrs, id: ast::DUMMY_NODE_ID })
- }
-
- fn mk_unary(&self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind {
- ExprKind::Unary(unop, expr)
- }
-
- fn mk_binary(&self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind {
- ExprKind::Binary(binop, lhs, rhs)
- }
-
- fn mk_call(&self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::ExprKind {
- ExprKind::Call(f, args)
- }
-
- fn mk_index(&self, expr: P<Expr>, idx: P<Expr>) -> ast::ExprKind {
- ExprKind::Index(expr, idx)
- }
-
- fn mk_range(&self,
- start: Option<P<Expr>>,
- end: Option<P<Expr>>,
- limits: RangeLimits)
- -> PResult<'a, ast::ExprKind> {
- if end.is_none() && limits == RangeLimits::Closed {
- Err(self.span_fatal_err(self.token.span, Error::InclusiveRangeWithNoEnd))
- } else {
- Ok(ExprKind::Range(start, end, limits))
- }
- }
-
- fn mk_assign_op(&self, binop: ast::BinOp,
- lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind {
- ExprKind::AssignOp(binop, lhs, rhs)
- }
-
fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, TokenStream)> {
let delim = match self.token.kind {
token::OpenDelim(delim) => delim,
Ok((delim, tts.into()))
}
- /// At the bottom (top?) of the precedence hierarchy,
- /// Parses things like parenthesized exprs, macros, `return`, etc.
- ///
- /// N.B., this does not parse outer attributes, and is private because it only works
- /// correctly if called from `parse_dot_or_call_expr()`.
- fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
- maybe_recover_from_interpolated_ty_qpath!(self, true);
- maybe_whole_expr!(self);
-
- // Outer attributes are already parsed and will be
- // added to the return value after the fact.
- //
- // Therefore, prevent sub-parser from parsing
- // attributes by giving them a empty "already parsed" list.
- let mut attrs = ThinVec::new();
-
- let lo = self.token.span;
- let mut hi = self.token.span;
-
- let ex: ExprKind;
-
- macro_rules! parse_lit {
- () => {
- match self.parse_lit() {
- Ok(literal) => {
- hi = self.prev_span;
- ex = ExprKind::Lit(literal);
- }
- Err(mut err) => {
- self.cancel(&mut err);
- return Err(self.expected_expression_found());
- }
- }
- }
- }
-
- // Note: when adding new syntax here, don't forget to adjust TokenKind::can_begin_expr().
- match self.token.kind {
- // This match arm is a special-case of the `_` match arm below and
- // could be removed without changing functionality, but it's faster
- // to have it here, especially for programs with large constants.
- token::Literal(_) => {
- parse_lit!()
- }
- token::OpenDelim(token::Paren) => {
- self.bump();
-
- attrs.extend(self.parse_inner_attributes()?);
-
- // (e) is parenthesized e
- // (e,) is a tuple with only one field, e
- let mut es = vec![];
- let mut trailing_comma = false;
- let mut recovered = false;
- while self.token != token::CloseDelim(token::Paren) {
- es.push(match self.parse_expr() {
- Ok(es) => es,
- Err(mut err) => {
- // recover from parse error in tuple list
- match self.token.kind {
- token::Ident(name, false)
- if name == kw::Underscore && self.look_ahead(1, |t| {
- t == &token::Comma
- }) => {
- // Special-case handling of `Foo<(_, _, _)>`
- err.emit();
- let sp = self.token.span;
- self.bump();
- self.mk_expr(sp, ExprKind::Err, ThinVec::new())
- }
- _ => return Ok(
- self.recover_seq_parse_error(token::Paren, lo, Err(err)),
- ),
- }
- }
- });
- recovered = self.expect_one_of(
- &[],
- &[token::Comma, token::CloseDelim(token::Paren)],
- )?;
- if self.eat(&token::Comma) {
- trailing_comma = true;
- } else {
- trailing_comma = false;
- break;
- }
- }
- if !recovered {
- self.bump();
- }
-
- hi = self.prev_span;
- ex = if es.len() == 1 && !trailing_comma {
- ExprKind::Paren(es.into_iter().nth(0).unwrap())
- } else {
- ExprKind::Tup(es)
- };
- }
- token::OpenDelim(token::Brace) => {
- return self.parse_block_expr(None, lo, BlockCheckMode::Default, attrs);
- }
- token::BinOp(token::Or) | token::OrOr => {
- return self.parse_lambda_expr(attrs);
- }
- token::OpenDelim(token::Bracket) => {
- self.bump();
-
- attrs.extend(self.parse_inner_attributes()?);
-
- if self.eat(&token::CloseDelim(token::Bracket)) {
- // Empty vector.
- ex = ExprKind::Array(Vec::new());
- } else {
- // Nonempty vector.
- let first_expr = self.parse_expr()?;
- if self.eat(&token::Semi) {
- // Repeating array syntax: [ 0; 512 ]
- let count = AnonConst {
- id: ast::DUMMY_NODE_ID,
- value: self.parse_expr()?,
- };
- self.expect(&token::CloseDelim(token::Bracket))?;
- ex = ExprKind::Repeat(first_expr, count);
- } else if self.eat(&token::Comma) {
- // Vector with two or more elements.
- let remaining_exprs = self.parse_seq_to_end(
- &token::CloseDelim(token::Bracket),
- SeqSep::trailing_allowed(token::Comma),
- |p| Ok(p.parse_expr()?)
- )?;
- let mut exprs = vec![first_expr];
- exprs.extend(remaining_exprs);
- ex = ExprKind::Array(exprs);
- } else {
- // Vector with one element.
- self.expect(&token::CloseDelim(token::Bracket))?;
- ex = ExprKind::Array(vec![first_expr]);
- }
- }
- hi = self.prev_span;
- }
- _ => {
- if self.eat_lt() {
- let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
- hi = path.span;
- return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs));
- }
- if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) {
- return self.parse_lambda_expr(attrs);
- }
- if self.eat_keyword(kw::If) {
- return self.parse_if_expr(attrs);
- }
- if self.eat_keyword(kw::For) {
- let lo = self.prev_span;
- return self.parse_for_expr(None, lo, attrs);
- }
- if self.eat_keyword(kw::While) {
- let lo = self.prev_span;
- return self.parse_while_expr(None, lo, attrs);
- }
- if let Some(label) = self.eat_label() {
- let lo = label.ident.span;
- self.expect(&token::Colon)?;
- if self.eat_keyword(kw::While) {
- return self.parse_while_expr(Some(label), lo, attrs)
- }
- if self.eat_keyword(kw::For) {
- return self.parse_for_expr(Some(label), lo, attrs)
- }
- if self.eat_keyword(kw::Loop) {
- return self.parse_loop_expr(Some(label), lo, attrs)
- }
- if self.token == token::OpenDelim(token::Brace) {
- return self.parse_block_expr(Some(label),
- lo,
- BlockCheckMode::Default,
- attrs);
- }
- let msg = "expected `while`, `for`, `loop` or `{` after a label";
- let mut err = self.fatal(msg);
- err.span_label(self.token.span, msg);
- return Err(err);
- }
- if self.eat_keyword(kw::Loop) {
- let lo = self.prev_span;
- return self.parse_loop_expr(None, lo, attrs);
- }
- if self.eat_keyword(kw::Continue) {
- let label = self.eat_label();
- let ex = ExprKind::Continue(label);
- let hi = self.prev_span;
- return Ok(self.mk_expr(lo.to(hi), ex, attrs));
- }
- if self.eat_keyword(kw::Match) {
- let match_sp = self.prev_span;
- return self.parse_match_expr(attrs).map_err(|mut err| {
- err.span_label(match_sp, "while parsing this match expression");
- err
- });
- }
- if self.eat_keyword(kw::Unsafe) {
- return self.parse_block_expr(
- None,
- lo,
- BlockCheckMode::Unsafe(ast::UserProvided),
- attrs);
- }
- if self.is_do_catch_block() {
- let mut db = self.fatal("found removed `do catch` syntax");
- db.help("Following RFC #2388, the new non-placeholder syntax is `try`");
- return Err(db);
- }
- if self.is_try_block() {
- let lo = self.token.span;
- assert!(self.eat_keyword(kw::Try));
- return self.parse_try_block(lo, attrs);
- }
-
- // Span::rust_2018() is somewhat expensive; don't get it repeatedly.
- let is_span_rust_2018 = self.token.span.rust_2018();
- if is_span_rust_2018 && self.check_keyword(kw::Async) {
- return if self.is_async_block() { // check for `async {` and `async move {`
- self.parse_async_block(attrs)
- } else {
- self.parse_lambda_expr(attrs)
- };
- }
- if self.eat_keyword(kw::Return) {
- if self.token.can_begin_expr() {
- let e = self.parse_expr()?;
- hi = e.span;
- ex = ExprKind::Ret(Some(e));
- } else {
- ex = ExprKind::Ret(None);
- }
- } else if self.eat_keyword(kw::Break) {
- let label = self.eat_label();
- let e = if self.token.can_begin_expr()
- && !(self.token == token::OpenDelim(token::Brace)
- && self.restrictions.contains(
- Restrictions::NO_STRUCT_LITERAL)) {
- Some(self.parse_expr()?)
- } else {
- None
- };
- ex = ExprKind::Break(label, e);
- hi = self.prev_span;
- } else if self.eat_keyword(kw::Yield) {
- if self.token.can_begin_expr() {
- let e = self.parse_expr()?;
- hi = e.span;
- ex = ExprKind::Yield(Some(e));
- } else {
- ex = ExprKind::Yield(None);
- }
- } else if self.eat_keyword(kw::Let) {
- return self.parse_let_expr(attrs);
- } else if is_span_rust_2018 && self.eat_keyword(kw::Await) {
- let (await_hi, e_kind) = self.parse_incorrect_await_syntax(lo, self.prev_span)?;
- hi = await_hi;
- ex = e_kind;
- } else if self.token.is_path_start() {
- let path = self.parse_path(PathStyle::Expr)?;
-
- // `!`, as an operator, is prefix, so we know this isn't that
- if self.eat(&token::Not) {
- // MACRO INVOCATION expression
- let (delim, tts) = self.expect_delimited_token_tree()?;
- hi = self.prev_span;
- ex = ExprKind::Mac(respan(lo.to(hi), Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- }));
- } else if self.check(&token::OpenDelim(token::Brace)) {
- if let Some(expr) = self.maybe_parse_struct_expr(lo, &path, &attrs) {
- return expr;
- } else {
- hi = path.span;
- ex = ExprKind::Path(None, path);
- }
- } else {
- hi = path.span;
- ex = ExprKind::Path(None, path);
- }
- } else {
- if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
- // Don't complain about bare semicolons after unclosed braces
- // recovery in order to keep the error count down. Fixing the
- // delimiters will possibly also fix the bare semicolon found in
- // expression context. For example, silence the following error:
- // ```
- // error: expected expression, found `;`
- // --> file.rs:2:13
- // |
- // 2 | foo(bar(;
- // | ^ expected expression
- // ```
- self.bump();
- return Ok(self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()));
- }
- parse_lit!()
- }
- }
- }
-
- let expr = self.mk_expr(lo.to(hi), ex, attrs);
- self.maybe_recover_from_bad_qpath(expr, true)
- }
-
- fn maybe_parse_struct_expr(
- &mut self,
- lo: Span,
- path: &ast::Path,
- attrs: &ThinVec<Attribute>,
- ) -> Option<PResult<'a, P<Expr>>> {
- let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
- let certainly_not_a_block = || self.look_ahead(1, |t| t.is_ident()) && (
- // `{ ident, ` cannot start a block
- self.look_ahead(2, |t| t == &token::Comma) ||
- self.look_ahead(2, |t| t == &token::Colon) && (
- // `{ ident: token, ` cannot start a block
- self.look_ahead(4, |t| t == &token::Comma) ||
- // `{ ident: ` cannot start a block unless it's a type ascription `ident: Type`
- self.look_ahead(3, |t| !t.can_begin_type())
- )
- );
-
- if struct_allowed || certainly_not_a_block() {
- // This is a struct literal, but we don't can't accept them here
- let expr = self.parse_struct_expr(lo, path.clone(), attrs.clone());
- if let (Ok(expr), false) = (&expr, struct_allowed) {
- self.struct_span_err(
- expr.span,
- "struct literals are not allowed here",
- )
- .multipart_suggestion(
- "surround the struct literal with parentheses",
- vec![
- (lo.shrink_to_lo(), "(".to_string()),
- (expr.span.shrink_to_hi(), ")".to_string()),
- ],
- Applicability::MachineApplicable,
- )
- .emit();
- }
- return Some(expr);
- }
- None
- }
-
- fn parse_struct_expr(&mut self, lo: Span, pth: ast::Path, mut attrs: ThinVec<Attribute>)
- -> PResult<'a, P<Expr>> {
- let struct_sp = lo.to(self.prev_span);
- self.bump();
- let mut fields = Vec::new();
- let mut base = None;
-
- attrs.extend(self.parse_inner_attributes()?);
-
- while self.token != token::CloseDelim(token::Brace) {
- if self.eat(&token::DotDot) {
- let exp_span = self.prev_span;
- match self.parse_expr() {
- Ok(e) => {
- base = Some(e);
- }
- Err(mut e) => {
- e.emit();
- self.recover_stmt();
- }
- }
- if self.token == token::Comma {
- self.struct_span_err(
- exp_span.to(self.prev_span),
- "cannot use a comma after the base struct",
- )
- .span_suggestion_short(
- self.token.span,
- "remove this comma",
- String::new(),
- Applicability::MachineApplicable
- )
- .note("the base struct must always be the last field")
- .emit();
- self.recover_stmt();
- }
- break;
- }
-
- let mut recovery_field = None;
- if let token::Ident(name, _) = self.token.kind {
- if !self.token.is_reserved_ident() && self.look_ahead(1, |t| *t == token::Colon) {
- // Use in case of error after field-looking code: `S { foo: () with a }`
- recovery_field = Some(ast::Field {
- ident: Ident::new(name, self.token.span),
- span: self.token.span,
- expr: self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()),
- is_shorthand: false,
- attrs: ThinVec::new(),
- });
- }
- }
- let mut parsed_field = None;
- match self.parse_field() {
- Ok(f) => parsed_field = Some(f),
- Err(mut e) => {
- e.span_label(struct_sp, "while parsing this struct");
- e.emit();
-
- // If the next token is a comma, then try to parse
- // what comes next as additional fields, rather than
- // bailing out until next `}`.
- if self.token != token::Comma {
- self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
- if self.token != token::Comma {
- break;
- }
- }
- }
- }
-
- match self.expect_one_of(&[token::Comma],
- &[token::CloseDelim(token::Brace)]) {
- Ok(_) => if let Some(f) = parsed_field.or(recovery_field) {
- // only include the field if there's no parse error for the field name
- fields.push(f);
- }
- Err(mut e) => {
- if let Some(f) = recovery_field {
- fields.push(f);
- }
- e.span_label(struct_sp, "while parsing this struct");
- e.emit();
- self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
- self.eat(&token::Comma);
- }
- }
- }
-
- let span = lo.to(self.token.span);
- self.expect(&token::CloseDelim(token::Brace))?;
- return Ok(self.mk_expr(span, ExprKind::Struct(pth, fields, base), attrs));
- }
-
fn parse_or_use_outer_attributes(&mut self,
already_parsed_attrs: Option<ThinVec<Attribute>>)
-> PResult<'a, ThinVec<Attribute>> {
}
}
- /// Parses a block or unsafe block.
- crate fn parse_block_expr(
- &mut self,
- opt_label: Option<Label>,
- lo: Span,
- blk_mode: BlockCheckMode,
- outer_attrs: ThinVec<Attribute>,
- ) -> PResult<'a, P<Expr>> {
- self.expect(&token::OpenDelim(token::Brace))?;
-
- let mut attrs = outer_attrs;
- attrs.extend(self.parse_inner_attributes()?);
-
- let blk = self.parse_block_tail(lo, blk_mode)?;
- return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs));
- }
-
- /// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
- fn parse_dot_or_call_expr(
- &mut self,
- already_parsed_attrs: Option<ThinVec<Attribute>>,
- ) -> PResult<'a, P<Expr>> {
- let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
-
- let b = self.parse_bottom_expr();
- let (span, b) = self.interpolated_or_expr_span(b)?;
- self.parse_dot_or_call_expr_with(b, span, attrs)
- }
-
- fn parse_dot_or_call_expr_with(
- &mut self,
- e0: P<Expr>,
- lo: Span,
- mut attrs: ThinVec<Attribute>,
- ) -> PResult<'a, P<Expr>> {
- // Stitch the list of outer attributes onto the return value.
- // A little bit ugly, but the best way given the current code
- // structure
- self.parse_dot_or_call_expr_with_(e0, lo).map(|expr|
- expr.map(|mut expr| {
- attrs.extend::<Vec<_>>(expr.attrs.into());
- expr.attrs = attrs;
- match expr.node {
- ExprKind::If(..) if !expr.attrs.is_empty() => {
- // Just point to the first attribute in there...
- let span = expr.attrs[0].span;
- self.span_err(span, "attributes are not yet allowed on `if` expressions");
- }
- _ => {}
- }
- expr
- })
- )
- }
-
- fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
- let span = lo.to(self.prev_span);
- let await_expr = self.mk_expr(span, ExprKind::Await(self_arg), ThinVec::new());
- self.recover_from_await_method_call();
- Ok(await_expr)
- }
-
- /// Assuming we have just parsed `.`, continue parsing into an expression.
- fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
- if self.token.span.rust_2018() && self.eat_keyword(kw::Await) {
- return self.mk_await_expr(self_arg, lo);
- }
-
- let segment = self.parse_path_segment(PathStyle::Expr)?;
- self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren));
-
- Ok(match self.token.kind {
- token::OpenDelim(token::Paren) => {
- // Method call `expr.f()`
- let mut args = self.parse_paren_expr_seq()?;
- args.insert(0, self_arg);
-
- let span = lo.to(self.prev_span);
- self.mk_expr(span, ExprKind::MethodCall(segment, args), ThinVec::new())
- }
- _ => {
- // Field access `expr.f`
- if let Some(args) = segment.args {
- self.span_err(args.span(),
- "field expressions may not have generic arguments");
- }
-
- let span = lo.to(self.prev_span);
- self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), ThinVec::new())
- }
- })
- }
-
- fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
- let mut e = e0;
- let mut hi;
- loop {
- // expr?
- while self.eat(&token::Question) {
- let hi = self.prev_span;
- e = self.mk_expr(lo.to(hi), ExprKind::Try(e), ThinVec::new());
- }
-
- // expr.f
- if self.eat(&token::Dot) {
- match self.token.kind {
- token::Ident(..) => {
- e = self.parse_dot_suffix(e, lo)?;
- }
- token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => {
- let span = self.token.span;
- self.bump();
- let field = ExprKind::Field(e, Ident::new(symbol, span));
- e = self.mk_expr(lo.to(span), field, ThinVec::new());
-
- self.expect_no_suffix(span, "a tuple index", suffix);
- }
- token::Literal(token::Lit { kind: token::Float, symbol, .. }) => {
- self.bump();
- let fstr = symbol.as_str();
- let msg = format!("unexpected token: `{}`", symbol);
- let mut err = self.diagnostic().struct_span_err(self.prev_span, &msg);
- err.span_label(self.prev_span, "unexpected token");
- if fstr.chars().all(|x| "0123456789.".contains(x)) {
- let float = match fstr.parse::<f64>().ok() {
- Some(f) => f,
- None => continue,
- };
- let sugg = pprust::to_string(|s| {
- s.popen();
- s.print_expr(&e);
- s.s.word( ".");
- s.print_usize(float.trunc() as usize);
- s.pclose();
- s.s.word(".");
- s.s.word(fstr.splitn(2, ".").last().unwrap().to_string())
- });
- err.span_suggestion(
- lo.to(self.prev_span),
- "try parenthesizing the first index",
- sugg,
- Applicability::MachineApplicable
- );
- }
- return Err(err);
-
- }
- _ => {
- // FIXME Could factor this out into non_fatal_unexpected or something.
- let actual = self.this_token_to_string();
- self.span_err(self.token.span, &format!("unexpected token: `{}`", actual));
- }
- }
- continue;
- }
- if self.expr_is_complete(&e) { break; }
- match self.token.kind {
- // expr(...)
- token::OpenDelim(token::Paren) => {
- let seq = self.parse_paren_expr_seq().map(|es| {
- let nd = self.mk_call(e, es);
- let hi = self.prev_span;
- self.mk_expr(lo.to(hi), nd, ThinVec::new())
- });
- e = self.recover_seq_parse_error(token::Paren, lo, seq);
- }
-
- // expr[...]
- // Could be either an index expression or a slicing expression.
- token::OpenDelim(token::Bracket) => {
- self.bump();
- let ix = self.parse_expr()?;
- hi = self.token.span;
- self.expect(&token::CloseDelim(token::Bracket))?;
- let index = self.mk_index(e, ix);
- e = self.mk_expr(lo.to(hi), index, ThinVec::new())
- }
- _ => return Ok(e)
- }
- }
- return Ok(e);
- }
-
- fn parse_paren_expr_seq(&mut self) -> PResult<'a, Vec<P<Expr>>> {
- self.parse_paren_comma_seq(|p| {
- match p.parse_expr() {
- Ok(expr) => Ok(expr),
- Err(mut err) => match p.token.kind {
- token::Ident(name, false)
- if name == kw::Underscore && p.look_ahead(1, |t| {
- t == &token::Comma
- }) => {
- // Special-case handling of `foo(_, _, _)`
- err.emit();
- let sp = p.token.span;
- p.bump();
- Ok(p.mk_expr(sp, ExprKind::Err, ThinVec::new()))
- }
- _ => Err(err),
- },
- }
- }).map(|(r, _)| r)
- }
-
crate fn process_potential_macro_variable(&mut self) {
self.token = match self.token.kind {
token::Dollar if self.token.span.ctxt() != SyntaxContext::empty() &&
TokenStream::new(result)
}
- /// Parse a prefix-unary-operator expr
- fn parse_prefix_expr(&mut self,
- already_parsed_attrs: Option<ThinVec<Attribute>>)
- -> PResult<'a, P<Expr>> {
- let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
- let lo = self.token.span;
- // Note: when adding new unary operators, don't forget to adjust TokenKind::can_begin_expr()
- let (hi, ex) = match self.token.kind {
- token::Not => {
- self.bump();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), self.mk_unary(UnOp::Not, e))
- }
- // Suggest `!` for bitwise negation when encountering a `~`
- token::Tilde => {
- self.bump();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- let span_of_tilde = lo;
- self.struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator")
- .span_suggestion_short(
- span_of_tilde,
- "use `!` to perform bitwise negation",
- "!".to_owned(),
- Applicability::MachineApplicable
- )
- .emit();
- (lo.to(span), self.mk_unary(UnOp::Not, e))
- }
- token::BinOp(token::Minus) => {
- self.bump();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), self.mk_unary(UnOp::Neg, e))
- }
- token::BinOp(token::Star) => {
- self.bump();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), self.mk_unary(UnOp::Deref, e))
- }
- token::BinOp(token::And) | token::AndAnd => {
- self.expect_and()?;
- let m = self.parse_mutability();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), ExprKind::AddrOf(m, e))
- }
- token::Ident(..) if self.token.is_keyword(kw::Box) => {
- self.bump();
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), ExprKind::Box(e))
- }
- token::Ident(..) if self.token.is_ident_named(sym::not) => {
- // `not` is just an ordinary identifier in Rust-the-language,
- // but as `rustc`-the-compiler, we can issue clever diagnostics
- // for confused users who really want to say `!`
- let token_cannot_continue_expr = |t: &Token| match t.kind {
- // These tokens can start an expression after `!`, but
- // can't continue an expression after an ident
- token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw),
- token::Literal(..) | token::Pound => true,
- _ => t.is_whole_expr(),
+ /// Evaluates the closure with restrictions in place.
+ ///
+ /// Afters the closure is evaluated, restrictions are reset.
+ fn with_res<F, T>(&mut self, r: Restrictions, f: F) -> T
+ where F: FnOnce(&mut Self) -> T
+ {
+ let old = self.restrictions;
+ self.restrictions = r;
+ let r = f(self);
+ self.restrictions = old;
+ return r;
+
+ }
+
+ fn parse_fn_args(&mut self, named_args: bool, allow_c_variadic: bool)
+ -> PResult<'a, (Vec<Arg> , bool)> {
+ let sp = self.token.span;
+ let mut c_variadic = false;
+ let (args, _): (Vec<Option<Arg>>, _) = self.parse_paren_comma_seq(|p| {
+ let do_not_enforce_named_arguments_for_c_variadic =
+ |token: &token::Token| -> bool {
+ if token == &token::DotDotDot {
+ false
+ } else {
+ named_args
+ }
};
- let cannot_continue_expr = self.look_ahead(1, token_cannot_continue_expr);
- if cannot_continue_expr {
- self.bump();
- // Emit the error ...
- self.struct_span_err(
- self.token.span,
- &format!("unexpected {} after identifier",self.this_token_descr())
- )
- .span_suggestion_short(
- // Span the `not` plus trailing whitespace to avoid
- // trailing whitespace after the `!` in our suggestion
- self.sess.source_map()
- .span_until_non_whitespace(lo.to(self.token.span)),
- "use `!` to perform logical negation",
- "!".to_owned(),
- Applicability::MachineApplicable
- )
- .emit();
- // —and recover! (just as if we were in the block
- // for the `token::Not` arm)
- let e = self.parse_prefix_expr(None);
- let (span, e) = self.interpolated_or_expr_span(e)?;
- (lo.to(span), self.mk_unary(UnOp::Not, e))
- } else {
- return self.parse_dot_or_call_expr(Some(attrs));
+ match p.parse_arg_general(
+ false,
+ allow_c_variadic,
+ do_not_enforce_named_arguments_for_c_variadic
+ ) {
+ Ok(arg) => {
+ if let TyKind::CVarArgs = arg.ty.node {
+ c_variadic = true;
+ if p.token != token::CloseDelim(token::Paren) {
+ let span = p.token.span;
+ p.span_err(span,
+ "`...` must be the last argument of a C-variadic function");
+ Ok(None)
+ } else {
+ Ok(Some(arg))
+ }
+ } else {
+ Ok(Some(arg))
+ }
+ },
+ Err(mut e) => {
+ e.emit();
+ let lo = p.prev_span;
+ // Skip every token until next possible arg or end.
+ p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]);
+ // Create a placeholder argument for proper arg count (issue #34264).
+ let span = lo.to(p.prev_span);
+ Ok(Some(dummy_arg(Ident::new(kw::Invalid, span))))
}
}
- _ => { return self.parse_dot_or_call_expr(Some(attrs)); }
- };
- return Ok(self.mk_expr(lo.to(hi), ex, attrs));
+ })?;
+
+ let args: Vec<_> = args.into_iter().filter_map(|x| x).collect();
+
+ if c_variadic && args.is_empty() {
+ self.span_err(sp,
+ "C-variadic function must be declared with at least one named argument");
+ }
+
+ Ok((args, c_variadic))
}
- /// Parses an associative expression.
+ /// Returns the parsed optional self argument and whether a self shortcut was used.
///
- /// This parses an expression accounting for associativity and precedence of the operators in
- /// the expression.
- #[inline]
- fn parse_assoc_expr(
- &mut self,
- already_parsed_attrs: Option<ThinVec<Attribute>>,
- ) -> PResult<'a, P<Expr>> {
- self.parse_assoc_expr_with(0, already_parsed_attrs.into())
- }
-
- /// Parses an associative expression with operators of at least `min_prec` precedence.
- fn parse_assoc_expr_with(
- &mut self,
- min_prec: usize,
- lhs: LhsExpr,
- ) -> PResult<'a, P<Expr>> {
- let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
- expr
- } else {
- let attrs = match lhs {
- LhsExpr::AttributesParsed(attrs) => Some(attrs),
- _ => None,
- };
- if [token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind) {
- return self.parse_prefix_range_expr(attrs);
- } else {
- self.parse_prefix_expr(attrs)?
- }
+ /// See `parse_self_arg_with_attrs` to collect attributes.
+ fn parse_self_arg(&mut self) -> PResult<'a, Option<Arg>> {
+ let expect_ident = |this: &mut Self| match this.token.kind {
+ // Preserve hygienic context.
+ token::Ident(name, _) =>
+ { let span = this.token.span; this.bump(); Ident::new(name, span) }
+ _ => unreachable!()
+ };
+ let isolated_self = |this: &mut Self, n| {
+ this.look_ahead(n, |t| t.is_keyword(kw::SelfLower)) &&
+ this.look_ahead(n + 1, |t| t != &token::ModSep)
};
- let last_type_ascription_set = self.last_type_ascription.is_some();
-
- match (self.expr_is_complete(&lhs), AssocOp::from_token(&self.token)) {
- (true, None) => {
- self.last_type_ascription = None;
- // Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071
- return Ok(lhs);
- }
- (false, _) => {} // continue parsing the expression
- // An exhaustive check is done in the following block, but these are checked first
- // because they *are* ambiguous but also reasonable looking incorrect syntax, so we
- // want to keep their span info to improve diagnostics in these cases in a later stage.
- (true, Some(AssocOp::Multiply)) | // `{ 42 } *foo = bar;` or `{ 42 } * 3`
- (true, Some(AssocOp::Subtract)) | // `{ 42 } -5`
- (true, Some(AssocOp::LAnd)) | // `{ 42 } &&x` (#61475)
- (true, Some(AssocOp::Add)) // `{ 42 } + 42
- // If the next token is a keyword, then the tokens above *are* unambiguously incorrect:
- // `if x { a } else { b } && if y { c } else { d }`
- if !self.look_ahead(1, |t| t.is_reserved_ident()) => {
- self.last_type_ascription = None;
- // These cases are ambiguous and can't be identified in the parser alone
- let sp = self.sess.source_map().start_point(self.token.span);
- self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
- return Ok(lhs);
- }
- (true, Some(ref op)) if !op.can_continue_expr_unambiguously() => {
- self.last_type_ascription = None;
- return Ok(lhs);
- }
- (true, Some(_)) => {
- // We've found an expression that would be parsed as a statement, but the next
- // token implies this should be parsed as an expression.
- // For example: `if let Some(x) = x { x } else { 0 } / 2`
- let mut err = self.struct_span_err(self.token.span, &format!(
- "expected expression, found `{}`",
- pprust::token_to_string(&self.token),
- ));
- err.span_label(self.token.span, "expected expression");
- self.sess.expr_parentheses_needed(
- &mut err,
- lhs.span,
- Some(pprust::expr_to_string(&lhs),
- ));
- err.emit();
- }
- }
- self.expected_tokens.push(TokenType::Operator);
- while let Some(op) = AssocOp::from_token(&self.token) {
-
- // Adjust the span for interpolated LHS to point to the `$lhs` token and not to what
- // it refers to. Interpolated identifiers are unwrapped early and never show up here
- // as `PrevTokenKind::Interpolated` so if LHS is a single identifier we always process
- // it as "interpolated", it doesn't change the answer for non-interpolated idents.
- let lhs_span = match (self.prev_token_kind, &lhs.node) {
- (PrevTokenKind::Interpolated, _) => self.prev_span,
- (PrevTokenKind::Ident, &ExprKind::Path(None, ref path))
- if path.segments.len() == 1 => self.prev_span,
- _ => lhs.span,
- };
-
- let cur_op_span = self.token.span;
- let restrictions = if op.is_assign_like() {
- self.restrictions & Restrictions::NO_STRUCT_LITERAL
- } else {
- self.restrictions
- };
- let prec = op.precedence();
- if prec < min_prec {
- break;
- }
- // Check for deprecated `...` syntax
- if self.token == token::DotDotDot && op == AssocOp::DotDotEq {
- self.err_dotdotdot_syntax(self.token.span);
- }
-
- self.bump();
- if op.is_comparison() {
- self.check_no_chained_comparison(&lhs, &op);
- }
- // Special cases:
- if op == AssocOp::As {
- lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
- continue
- } else if op == AssocOp::Colon {
- let maybe_path = self.could_ascription_be_path(&lhs.node);
- self.last_type_ascription = Some((self.prev_span, maybe_path));
- lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type)?;
- continue
- } else if op == AssocOp::DotDot || op == AssocOp::DotDotEq {
- // If we didn’t have to handle `x..`/`x..=`, it would be pretty easy to
- // generalise it to the Fixity::None code.
- //
- // We have 2 alternatives here: `x..y`/`x..=y` and `x..`/`x..=` The other
- // two variants are handled with `parse_prefix_range_expr` call above.
- let rhs = if self.is_at_start_of_range_notation_rhs() {
- Some(self.parse_assoc_expr_with(prec + 1, LhsExpr::NotYetParsed)?)
- } else {
- None
- };
- let (lhs_span, rhs_span) = (lhs.span, if let Some(ref x) = rhs {
- x.span
- } else {
- cur_op_span
- });
- let limits = if op == AssocOp::DotDot {
- RangeLimits::HalfOpen
+ // Parse optional `self` parameter of a method.
+ // Only a limited set of initial token sequences is considered `self` parameters; anything
+ // else is parsed as a normal function parameter list, so some lookahead is required.
+ let eself_lo = self.token.span;
+ let (eself, eself_ident, eself_hi) = match self.token.kind {
+ token::BinOp(token::And) => {
+ // `&self`
+ // `&mut self`
+ // `&'lt self`
+ // `&'lt mut self`
+ // `¬_self`
+ (if isolated_self(self, 1) {
+ self.bump();
+ SelfKind::Region(None, Mutability::Immutable)
+ } else if self.is_keyword_ahead(1, &[kw::Mut]) &&
+ isolated_self(self, 2) {
+ self.bump();
+ self.bump();
+ SelfKind::Region(None, Mutability::Mutable)
+ } else if self.look_ahead(1, |t| t.is_lifetime()) &&
+ isolated_self(self, 2) {
+ self.bump();
+ let lt = self.expect_lifetime();
+ SelfKind::Region(Some(lt), Mutability::Immutable)
+ } else if self.look_ahead(1, |t| t.is_lifetime()) &&
+ self.is_keyword_ahead(2, &[kw::Mut]) &&
+ isolated_self(self, 3) {
+ self.bump();
+ let lt = self.expect_lifetime();
+ self.bump();
+ SelfKind::Region(Some(lt), Mutability::Mutable)
} else {
- RangeLimits::Closed
- };
-
- let r = self.mk_range(Some(lhs), rhs, limits)?;
- lhs = self.mk_expr(lhs_span.to(rhs_span), r, ThinVec::new());
- break
+ return Ok(None);
+ }, expect_ident(self), self.prev_span)
}
-
- let fixity = op.fixity();
- let prec_adjustment = match fixity {
- Fixity::Right => 0,
- Fixity::Left => 1,
- // We currently have no non-associative operators that are not handled above by
- // the special cases. The code is here only for future convenience.
- Fixity::None => 1,
- };
- let rhs = self.with_res(
- restrictions - Restrictions::STMT_EXPR,
- |this| this.parse_assoc_expr_with(prec + prec_adjustment, LhsExpr::NotYetParsed)
- )?;
-
- // Make sure that the span of the parent node is larger than the span of lhs and rhs,
- // including the attributes.
- let lhs_span = lhs
- .attrs
- .iter()
- .filter(|a| a.style == AttrStyle::Outer)
- .next()
- .map_or(lhs_span, |a| a.span);
- let span = lhs_span.to(rhs.span);
- lhs = match op {
- AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
- AssocOp::Modulus | AssocOp::LAnd | AssocOp::LOr | AssocOp::BitXor |
- AssocOp::BitAnd | AssocOp::BitOr | AssocOp::ShiftLeft | AssocOp::ShiftRight |
- AssocOp::Equal | AssocOp::Less | AssocOp::LessEqual | AssocOp::NotEqual |
- AssocOp::Greater | AssocOp::GreaterEqual => {
- let ast_op = op.to_ast_binop().unwrap();
- let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
- self.mk_expr(span, binary, ThinVec::new())
- }
- AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()),
- AssocOp::AssignOp(k) => {
- let aop = match k {
- token::Plus => BinOpKind::Add,
- token::Minus => BinOpKind::Sub,
- token::Star => BinOpKind::Mul,
- token::Slash => BinOpKind::Div,
- token::Percent => BinOpKind::Rem,
- token::Caret => BinOpKind::BitXor,
- token::And => BinOpKind::BitAnd,
- token::Or => BinOpKind::BitOr,
- token::Shl => BinOpKind::Shl,
- token::Shr => BinOpKind::Shr,
- };
- let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
- self.mk_expr(span, aopexpr, ThinVec::new())
- }
- AssocOp::As | AssocOp::Colon | AssocOp::DotDot | AssocOp::DotDotEq => {
- self.bug("AssocOp should have been handled by special case")
- }
- };
-
- if let Fixity::None = fixity { break }
- }
- if last_type_ascription_set {
- self.last_type_ascription = None;
- }
- Ok(lhs)
- }
-
- fn parse_assoc_op_cast(&mut self, lhs: P<Expr>, lhs_span: Span,
- expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind)
- -> PResult<'a, P<Expr>> {
- let mk_expr = |this: &mut Self, rhs: P<Ty>| {
- this.mk_expr(lhs_span.to(rhs.span), expr_kind(lhs, rhs), ThinVec::new())
- };
-
- // Save the state of the parser before parsing type normally, in case there is a
- // LessThan comparison after this cast.
- let parser_snapshot_before_type = self.clone();
- match self.parse_ty_no_plus() {
- Ok(rhs) => {
- Ok(mk_expr(self, rhs))
+ token::BinOp(token::Star) => {
+ // `*self`
+ // `*const self`
+ // `*mut self`
+ // `*not_self`
+ // Emit special error for `self` cases.
+ let msg = "cannot pass `self` by raw pointer";
+ (if isolated_self(self, 1) {
+ self.bump();
+ self.struct_span_err(self.token.span, msg)
+ .span_label(self.token.span, msg)
+ .emit();
+ SelfKind::Value(Mutability::Immutable)
+ } else if self.look_ahead(1, |t| t.is_mutability()) &&
+ isolated_self(self, 2) {
+ self.bump();
+ self.bump();
+ self.struct_span_err(self.token.span, msg)
+ .span_label(self.token.span, msg)
+ .emit();
+ SelfKind::Value(Mutability::Immutable)
+ } else {
+ return Ok(None);
+ }, expect_ident(self), self.prev_span)
}
- Err(mut type_err) => {
- // Rewind to before attempting to parse the type with generics, to recover
- // from situations like `x as usize < y` in which we first tried to parse
- // `usize < y` as a type with generic arguments.
- let parser_snapshot_after_type = self.clone();
- mem::replace(self, parser_snapshot_before_type);
-
- match self.parse_path(PathStyle::Expr) {
- Ok(path) => {
- let (op_noun, op_verb) = match self.token.kind {
- token::Lt => ("comparison", "comparing"),
- token::BinOp(token::Shl) => ("shift", "shifting"),
- _ => {
- // We can end up here even without `<` being the next token, for
- // example because `parse_ty_no_plus` returns `Err` on keywords,
- // but `parse_path` returns `Ok` on them due to error recovery.
- // Return original error and parser state.
- mem::replace(self, parser_snapshot_after_type);
- return Err(type_err);
- }
- };
-
- // Successfully parsed the type path leaving a `<` yet to parse.
- type_err.cancel();
-
- // Report non-fatal diagnostics, keep `x as usize` as an expression
- // in AST and continue parsing.
- let msg = format!("`<` is interpreted as a start of generic \
- arguments for `{}`, not a {}", path, op_noun);
- let span_after_type = parser_snapshot_after_type.token.span;
- let expr = mk_expr(self, P(Ty {
- span: path.span,
- node: TyKind::Path(None, path),
- id: ast::DUMMY_NODE_ID
- }));
-
- let expr_str = self.span_to_snippet(expr.span)
- .unwrap_or_else(|_| pprust::expr_to_string(&expr));
-
- self.struct_span_err(self.token.span, &msg)
- .span_label(
- self.look_ahead(1, |t| t.span).to(span_after_type),
- "interpreted as generic arguments"
- )
- .span_label(self.token.span, format!("not interpreted as {}", op_noun))
- .span_suggestion(
- expr.span,
- &format!("try {} the cast value", op_verb),
- format!("({})", expr_str),
- Applicability::MachineApplicable
- )
- .emit();
-
- Ok(expr)
- }
- Err(mut path_err) => {
- // Couldn't parse as a path, return original error and parser state.
- path_err.cancel();
- mem::replace(self, parser_snapshot_after_type);
- Err(type_err)
- }
+ token::Ident(..) => {
+ if isolated_self(self, 0) {
+ // `self`
+ // `self: TYPE`
+ let eself_ident = expect_ident(self);
+ let eself_hi = self.prev_span;
+ (if self.eat(&token::Colon) {
+ let ty = self.parse_ty()?;
+ SelfKind::Explicit(ty, Mutability::Immutable)
+ } else {
+ SelfKind::Value(Mutability::Immutable)
+ }, eself_ident, eself_hi)
+ } else if self.token.is_keyword(kw::Mut) &&
+ isolated_self(self, 1) {
+ // `mut self`
+ // `mut self: TYPE`
+ self.bump();
+ let eself_ident = expect_ident(self);
+ let eself_hi = self.prev_span;
+ (if self.eat(&token::Colon) {
+ let ty = self.parse_ty()?;
+ SelfKind::Explicit(ty, Mutability::Mutable)
+ } else {
+ SelfKind::Value(Mutability::Mutable)
+ }, eself_ident, eself_hi)
+ } else {
+ return Ok(None);
}
}
- }
- }
-
- /// Parse prefix-forms of range notation: `..expr`, `..`, `..=expr`
- fn parse_prefix_range_expr(&mut self,
- already_parsed_attrs: Option<ThinVec<Attribute>>)
- -> PResult<'a, P<Expr>> {
- // Check for deprecated `...` syntax
- if self.token == token::DotDotDot {
- self.err_dotdotdot_syntax(self.token.span);
- }
-
- debug_assert!([token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind),
- "parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
- self.token);
- let tok = self.token.clone();
- let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
- let lo = self.token.span;
- let mut hi = self.token.span;
- self.bump();
- let opt_end = if self.is_at_start_of_range_notation_rhs() {
- // RHS must be parsed with more associativity than the dots.
- let next_prec = AssocOp::from_token(&tok).unwrap().precedence() + 1;
- Some(self.parse_assoc_expr_with(next_prec,
- LhsExpr::NotYetParsed)
- .map(|x|{
- hi = x.span;
- x
- })?)
- } else {
- None
- };
- let limits = if tok == token::DotDot {
- RangeLimits::HalfOpen
- } else {
- RangeLimits::Closed
+ _ => return Ok(None),
};
- let r = self.mk_range(None, opt_end, limits)?;
- Ok(self.mk_expr(lo.to(hi), r, attrs))
- }
-
- fn is_at_start_of_range_notation_rhs(&self) -> bool {
- if self.token.can_begin_expr() {
- // parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
- if self.token == token::OpenDelim(token::Brace) {
- return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
- }
- true
- } else {
- false
- }
- }
-
- /// Parses an `if` expression (`if` token already eaten).
- fn parse_if_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let lo = self.prev_span;
- let cond = self.parse_cond_expr()?;
-
- // Verify that the parsed `if` condition makes sense as a condition. If it is a block, then
- // verify that the last statement is either an implicit return (no `;`) or an explicit
- // return. This won't catch blocks with an explicit `return`, but that would be caught by
- // the dead code lint.
- if self.eat_keyword(kw::Else) || !cond.returns() {
- let sp = self.sess.source_map().next_point(lo);
- let mut err = self.diagnostic()
- .struct_span_err(sp, "missing condition for `if` statemement");
- err.span_label(sp, "expected if condition here");
- return Err(err)
- }
- let not_block = self.token != token::OpenDelim(token::Brace);
- let thn = self.parse_block().map_err(|mut err| {
- if not_block {
- err.span_label(lo, "this `if` statement has a condition, but no block");
- }
- err
- })?;
- let mut els: Option<P<Expr>> = None;
- let mut hi = thn.span;
- if self.eat_keyword(kw::Else) {
- let elexpr = self.parse_else_expr()?;
- hi = elexpr.span;
- els = Some(elexpr);
- }
- Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs))
- }
-
- /// Parse the condition of a `if`- or `while`-expression
- fn parse_cond_expr(&mut self) -> PResult<'a, P<Expr>> {
- let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
-
- if let ExprKind::Let(..) = cond.node {
- // Remove the last feature gating of a `let` expression since it's stable.
- let last = self.sess.let_chains_spans.borrow_mut().pop();
- debug_assert_eq!(cond.span, last.unwrap());
- }
-
- Ok(cond)
+ let eself = source_map::respan(eself_lo.to(eself_hi), eself);
+ Ok(Some(Arg::from_self(ThinVec::default(), eself, eself_ident)))
}
- /// Parses a `let $pats = $expr` pseudo-expression.
- /// The `let` token has already been eaten.
- fn parse_let_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let lo = self.prev_span;
- let pats = self.parse_pats()?;
- self.expect(&token::Eq)?;
- let expr = self.with_res(
- Restrictions::NO_STRUCT_LITERAL,
- |this| this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into())
- )?;
- let span = lo.to(expr.span);
- self.sess.let_chains_spans.borrow_mut().push(span);
- Ok(self.mk_expr(span, ExprKind::Let(pats, expr), attrs))
+ /// Returns the parsed optional self argument with attributes and whether a self
+ /// shortcut was used.
+ fn parse_self_arg_with_attrs(&mut self) -> PResult<'a, Option<Arg>> {
+ let attrs = self.parse_arg_attributes()?;
+ let arg_opt = self.parse_self_arg()?;
+ Ok(arg_opt.map(|mut arg| {
+ arg.attrs = attrs.into();
+ arg
+ }))
}
- /// Parses `move |args| expr`.
- fn parse_lambda_expr(&mut self,
- attrs: ThinVec<Attribute>)
- -> PResult<'a, P<Expr>>
+ /// Parses the parameter list and result type of a function that may have a `self` parameter.
+ fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> PResult<'a, P<FnDecl>>
+ where F: FnMut(&mut Parser<'a>) -> PResult<'a, Arg>,
{
- let lo = self.token.span;
-
- let movability = if self.eat_keyword(kw::Static) {
- Movability::Static
- } else {
- Movability::Movable
- };
+ self.expect(&token::OpenDelim(token::Paren))?;
- let asyncness = if self.token.span.rust_2018() {
- self.parse_asyncness()
- } else {
- IsAsync::NotAsync
- };
- if asyncness.is_async() {
- // Feature gate `async ||` closures.
- self.sess.async_closure_spans.borrow_mut().push(self.prev_span);
- }
+ // Parse optional self argument.
+ let self_arg = self.parse_self_arg_with_attrs()?;
- let capture_clause = self.parse_capture_clause();
- let decl = self.parse_fn_block_decl()?;
- let decl_hi = self.prev_span;
- let body = match decl.output {
- FunctionRetTy::Default(_) => {
- let restrictions = self.restrictions - Restrictions::STMT_EXPR;
- self.parse_expr_res(restrictions, None)?
- },
- _ => {
- // If an explicit return type is given, require a
- // block to appear (RFC 968).
- let body_lo = self.token.span;
- self.parse_block_expr(None, body_lo, BlockCheckMode::Default, ThinVec::new())?
+ // Parse the rest of the function parameter list.
+ let sep = SeqSep::trailing_allowed(token::Comma);
+ let (mut fn_inputs, recovered) = if let Some(self_arg) = self_arg {
+ if self.check(&token::CloseDelim(token::Paren)) {
+ (vec![self_arg], false)
+ } else if self.eat(&token::Comma) {
+ let mut fn_inputs = vec![self_arg];
+ let (mut input, _, recovered) = self.parse_seq_to_before_end(
+ &token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
+ fn_inputs.append(&mut input);
+ (fn_inputs, recovered)
+ } else {
+ match self.expect_one_of(&[], &[]) {
+ Err(err) => return Err(err),
+ Ok(recovered) => (vec![self_arg], recovered),
+ }
}
- };
-
- Ok(self.mk_expr(
- lo.to(body.span),
- ExprKind::Closure(capture_clause, asyncness, movability, decl, body, lo.to(decl_hi)),
- attrs))
- }
-
- /// `else` token already eaten
- fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
- if self.eat_keyword(kw::If) {
- return self.parse_if_expr(ThinVec::new());
} else {
- let blk = self.parse_block()?;
- return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), ThinVec::new()));
- }
- }
-
- /// Parse a 'for' .. 'in' expression ('for' token already eaten)
- fn parse_for_expr(
- &mut self,
- opt_label: Option<Label>,
- span_lo: Span,
- mut attrs: ThinVec<Attribute>
- ) -> PResult<'a, P<Expr>> {
- // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
-
- // Record whether we are about to parse `for (`.
- // This is used below for recovery in case of `for ( $stuff ) $block`
- // in which case we will suggest `for $stuff $block`.
- let begin_paren = match self.token.kind {
- token::OpenDelim(token::Paren) => Some(self.token.span),
- _ => None,
+ let (input, _, recovered) =
+ self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
+ (input, recovered)
};
- let pat = self.parse_top_level_pat()?;
- if !self.eat_keyword(kw::In) {
- let in_span = self.prev_span.between(self.token.span);
- self.struct_span_err(in_span, "missing `in` in `for` loop")
- .span_suggestion_short(
- in_span,
- "try adding `in` here", " in ".into(),
- // has been misleading, at least in the past (closed Issue #48492)
- Applicability::MaybeIncorrect
- )
- .emit();
+ if !recovered {
+ // Parse closing paren and return type.
+ self.expect(&token::CloseDelim(token::Paren))?;
}
- let in_span = self.prev_span;
- self.check_for_for_in_in_typo(in_span);
- let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
-
- let pat = self.recover_parens_around_for_head(pat, &expr, begin_paren);
-
- let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
- attrs.extend(iattrs);
+ // Replace duplicated recovered arguments with `_` pattern to avoid unecessary errors.
+ self.deduplicate_recovered_arg_names(&mut fn_inputs);
- let hi = self.prev_span;
- Ok(self.mk_expr(span_lo.to(hi), ExprKind::ForLoop(pat, expr, loop_block, opt_label), attrs))
+ Ok(P(FnDecl {
+ inputs: fn_inputs,
+ output: self.parse_ret_ty(true)?,
+ c_variadic: false
+ }))
}
- /// Parses a `while` or `while let` expression (`while` token already eaten).
- fn parse_while_expr(&mut self, opt_label: Option<Label>,
- span_lo: Span,
- mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let cond = self.parse_cond_expr()?;
- let (iattrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(iattrs);
- let span = span_lo.to(body.span);
- Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs))
+ fn is_crate_vis(&self) -> bool {
+ self.token.is_keyword(kw::Crate) && self.look_ahead(1, |t| t != &token::ModSep)
}
- /// Parse `loop {...}`, `loop` token already eaten.
- fn parse_loop_expr(&mut self, opt_label: Option<Label>,
- span_lo: Span,
- mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let (iattrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(iattrs);
- let span = span_lo.to(body.span);
- Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs))
- }
-
- /// Parse an optional `move` prefix to a closure lke construct.
- fn parse_capture_clause(&mut self) -> CaptureBy {
- if self.eat_keyword(kw::Move) {
- CaptureBy::Value
- } else {
- CaptureBy::Ref
- }
- }
-
- /// Parses an `async move? {...}` expression.
- pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let span_lo = self.token.span;
- self.expect_keyword(kw::Async)?;
- let capture_clause = self.parse_capture_clause();
- let (iattrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(iattrs);
- Ok(self.mk_expr(
- span_lo.to(body.span),
- ExprKind::Async(capture_clause, ast::DUMMY_NODE_ID, body), attrs))
- }
-
- /// Parses a `try {...}` expression (`try` token already eaten).
- fn parse_try_block(&mut self, span_lo: Span, mut attrs: ThinVec<Attribute>)
- -> PResult<'a, P<Expr>>
- {
- let (iattrs, body) = self.parse_inner_attrs_and_block()?;
- attrs.extend(iattrs);
- if self.eat_keyword(kw::Catch) {
- let mut error = self.struct_span_err(self.prev_span,
- "keyword `catch` cannot follow a `try` block");
- error.help("try using `match` on the result of the `try` block instead");
- error.emit();
- Err(error)
- } else {
- Ok(self.mk_expr(span_lo.to(body.span), ExprKind::TryBlock(body), attrs))
- }
- }
-
- // `match` token already eaten
- fn parse_match_expr(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
- let match_span = self.prev_span;
- let lo = self.prev_span;
- let discriminant = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL,
- None)?;
- if let Err(mut e) = self.expect(&token::OpenDelim(token::Brace)) {
- if self.token == token::Semi {
- e.span_suggestion_short(
- match_span,
- "try removing this `match`",
- String::new(),
- Applicability::MaybeIncorrect // speculative
- );
- }
- return Err(e)
- }
- attrs.extend(self.parse_inner_attributes()?);
-
- let mut arms: Vec<Arm> = Vec::new();
- while self.token != token::CloseDelim(token::Brace) {
- match self.parse_arm() {
- Ok(arm) => arms.push(arm),
- Err(mut e) => {
- // Recover by skipping to the end of the block.
- e.emit();
- self.recover_stmt();
- let span = lo.to(self.token.span);
- if self.token == token::CloseDelim(token::Brace) {
- self.bump();
- }
- return Ok(self.mk_expr(span, ExprKind::Match(discriminant, arms), attrs));
- }
- }
- }
- let hi = self.token.span;
- self.bump();
- return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs));
- }
-
- crate fn parse_arm(&mut self) -> PResult<'a, Arm> {
- let attrs = self.parse_outer_attributes()?;
- let lo = self.token.span;
- let pats = self.parse_pats()?;
- let guard = if self.eat_keyword(kw::If) {
- Some(self.parse_expr()?)
- } else {
- None
- };
- let arrow_span = self.token.span;
- self.expect(&token::FatArrow)?;
- let arm_start_span = self.token.span;
-
- let expr = self.parse_expr_res(Restrictions::STMT_EXPR, None)
- .map_err(|mut err| {
- err.span_label(arrow_span, "while parsing the `match` arm starting here");
- err
- })?;
-
- let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
- && self.token != token::CloseDelim(token::Brace);
-
- let hi = self.token.span;
-
- if require_comma {
- let cm = self.sess.source_map();
- self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)])
- .map_err(|mut err| {
- match (cm.span_to_lines(expr.span), cm.span_to_lines(arm_start_span)) {
- (Ok(ref expr_lines), Ok(ref arm_start_lines))
- if arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col
- && expr_lines.lines.len() == 2
- && self.token == token::FatArrow => {
- // We check whether there's any trailing code in the parse span,
- // if there isn't, we very likely have the following:
- //
- // X | &Y => "y"
- // | -- - missing comma
- // | |
- // | arrow_span
- // X | &X => "x"
- // | - ^^ self.token.span
- // | |
- // | parsed until here as `"y" & X`
- err.span_suggestion_short(
- cm.next_point(arm_start_span),
- "missing a comma here to end this `match` arm",
- ",".to_owned(),
- Applicability::MachineApplicable
- );
- }
- _ => {
- err.span_label(arrow_span,
- "while parsing the `match` arm starting here");
- }
- }
- err
- })?;
- } else {
- self.eat(&token::Comma);
- }
-
- Ok(ast::Arm {
- attrs,
- pats,
- guard,
- body: expr,
- span: lo.to(hi),
- })
- }
-
- /// Parses an expression.
- #[inline]
- pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
- self.parse_expr_res(Restrictions::empty(), None)
- }
-
- /// Evaluates the closure with restrictions in place.
- ///
- /// Afters the closure is evaluated, restrictions are reset.
- fn with_res<F, T>(&mut self, r: Restrictions, f: F) -> T
- where F: FnOnce(&mut Self) -> T
- {
- let old = self.restrictions;
- self.restrictions = r;
- let r = f(self);
- self.restrictions = old;
- return r;
-
- }
-
- /// Parses an expression, subject to the given restrictions.
- #[inline]
- fn parse_expr_res(&mut self, r: Restrictions,
- already_parsed_attrs: Option<ThinVec<Attribute>>)
- -> PResult<'a, P<Expr>> {
- self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
- }
-
- /// Parses the RHS of a local variable declaration (e.g., '= 14;').
- fn parse_initializer(&mut self, skip_eq: bool) -> PResult<'a, Option<P<Expr>>> {
- if self.eat(&token::Eq) {
- Ok(Some(self.parse_expr()?))
- } else if skip_eq {
- Ok(Some(self.parse_expr()?))
- } else {
- Ok(None)
- }
- }
-
- /// Parses patterns, separated by '|' s.
- fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
- // Allow a '|' before the pats (RFC 1925 + RFC 2530)
- self.eat(&token::BinOp(token::Or));
-
- let mut pats = Vec::new();
- loop {
- pats.push(self.parse_top_level_pat()?);
-
- if self.token == token::OrOr {
- self.struct_span_err(self.token.span, "unexpected token `||` after pattern")
- .span_suggestion(
- self.token.span,
- "use a single `|` to specify multiple patterns",
- "|".to_owned(),
- Applicability::MachineApplicable
- )
- .emit();
- self.bump();
- } else if self.eat(&token::BinOp(token::Or)) {
- // This is a No-op. Continue the loop to parse the next
- // pattern.
- } else {
- return Ok(pats);
- }
- };
- }
-
- fn parse_pat_field(
- &mut self,
- lo: Span,
- attrs: Vec<Attribute>
- ) -> PResult<'a, source_map::Spanned<ast::FieldPat>> {
- // Check if a colon exists one ahead. This means we're parsing a fieldname.
- let hi;
- let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
- // Parsing a pattern of the form "fieldname: pat"
- let fieldname = self.parse_field_name()?;
- self.bump();
- let pat = self.parse_pat(None)?;
- hi = pat.span;
- (pat, fieldname, false)
- } else {
- // Parsing a pattern of the form "(box) (ref) (mut) fieldname"
- let is_box = self.eat_keyword(kw::Box);
- let boxed_span = self.token.span;
- let is_ref = self.eat_keyword(kw::Ref);
- let is_mut = self.eat_keyword(kw::Mut);
- let fieldname = self.parse_ident()?;
- hi = self.prev_span;
-
- let bind_type = match (is_ref, is_mut) {
- (true, true) => BindingMode::ByRef(Mutability::Mutable),
- (true, false) => BindingMode::ByRef(Mutability::Immutable),
- (false, true) => BindingMode::ByValue(Mutability::Mutable),
- (false, false) => BindingMode::ByValue(Mutability::Immutable),
- };
- let fieldpat = P(Pat {
- id: ast::DUMMY_NODE_ID,
- node: PatKind::Ident(bind_type, fieldname, None),
- span: boxed_span.to(hi),
- });
-
- let subpat = if is_box {
- P(Pat {
- id: ast::DUMMY_NODE_ID,
- node: PatKind::Box(fieldpat),
- span: lo.to(hi),
- })
- } else {
- fieldpat
- };
- (subpat, fieldname, true)
- };
-
- Ok(source_map::Spanned {
- span: lo.to(hi),
- node: ast::FieldPat {
- ident: fieldname,
- pat: subpat,
- is_shorthand,
- attrs: attrs.into(),
- }
- })
- }
-
- /// Parses the fields of a struct-like pattern.
- fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<source_map::Spanned<ast::FieldPat>>, bool)> {
- let mut fields = Vec::new();
- let mut etc = false;
- let mut ate_comma = true;
- let mut delayed_err: Option<DiagnosticBuilder<'a>> = None;
- let mut etc_span = None;
-
- while self.token != token::CloseDelim(token::Brace) {
- let attrs = match self.parse_outer_attributes() {
- Ok(attrs) => attrs,
- Err(err) => {
- if let Some(mut delayed) = delayed_err {
- delayed.emit();
- }
- return Err(err);
- },
- };
- let lo = self.token.span;
-
- // check that a comma comes after every field
- if !ate_comma {
- let err = self.struct_span_err(self.prev_span, "expected `,`");
- if let Some(mut delayed) = delayed_err {
- delayed.emit();
- }
- return Err(err);
- }
- ate_comma = false;
-
- if self.check(&token::DotDot) || self.token == token::DotDotDot {
- etc = true;
- let mut etc_sp = self.token.span;
-
- if self.token == token::DotDotDot { // Issue #46718
- // Accept `...` as if it were `..` to avoid further errors
- self.struct_span_err(self.token.span, "expected field pattern, found `...`")
- .span_suggestion(
- self.token.span,
- "to omit remaining fields, use one fewer `.`",
- "..".to_owned(),
- Applicability::MachineApplicable
- )
- .emit();
- }
- self.bump(); // `..` || `...`
-
- if self.token == token::CloseDelim(token::Brace) {
- etc_span = Some(etc_sp);
- break;
- }
- let token_str = self.this_token_descr();
- let mut err = self.fatal(&format!("expected `}}`, found {}", token_str));
-
- err.span_label(self.token.span, "expected `}`");
- let mut comma_sp = None;
- if self.token == token::Comma { // Issue #49257
- let nw_span = self.sess.source_map().span_until_non_whitespace(self.token.span);
- etc_sp = etc_sp.to(nw_span);
- err.span_label(etc_sp,
- "`..` must be at the end and cannot have a trailing comma");
- comma_sp = Some(self.token.span);
- self.bump();
- ate_comma = true;
- }
-
- etc_span = Some(etc_sp.until(self.token.span));
- if self.token == token::CloseDelim(token::Brace) {
- // If the struct looks otherwise well formed, recover and continue.
- if let Some(sp) = comma_sp {
- err.span_suggestion_short(
- sp,
- "remove this comma",
- String::new(),
- Applicability::MachineApplicable,
- );
- }
- err.emit();
- break;
- } else if self.token.is_ident() && ate_comma {
- // Accept fields coming after `..,`.
- // This way we avoid "pattern missing fields" errors afterwards.
- // We delay this error until the end in order to have a span for a
- // suggested fix.
- if let Some(mut delayed_err) = delayed_err {
- delayed_err.emit();
- return Err(err);
- } else {
- delayed_err = Some(err);
- }
- } else {
- if let Some(mut err) = delayed_err {
- err.emit();
- }
- return Err(err);
- }
- }
-
- fields.push(match self.parse_pat_field(lo, attrs) {
- Ok(field) => field,
- Err(err) => {
- if let Some(mut delayed_err) = delayed_err {
- delayed_err.emit();
- }
- return Err(err);
- }
- });
- ate_comma = self.eat(&token::Comma);
- }
-
- if let Some(mut err) = delayed_err {
- if let Some(etc_span) = etc_span {
- err.multipart_suggestion(
- "move the `..` to the end of the field list",
- vec![
- (etc_span, String::new()),
- (self.token.span, format!("{}.. }}", if ate_comma { "" } else { ", " })),
- ],
- Applicability::MachineApplicable,
- );
- }
- err.emit();
- }
- return Ok((fields, etc));
- }
-
- fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
- if self.token.is_path_start() {
- let lo = self.token.span;
- let (qself, path) = if self.eat_lt() {
- // Parse a qualified path
- let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
- (Some(qself), path)
- } else {
- // Parse an unqualified path
- (None, self.parse_path(PathStyle::Expr)?)
- };
- let hi = self.prev_span;
- Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path), ThinVec::new()))
- } else {
- self.parse_literal_maybe_minus()
- }
- }
-
- /// Is the current token suitable as the start of a range patterns end?
- fn is_pat_range_end_start(&self) -> bool {
- self.token.is_path_start() // e.g. `MY_CONST`;
- || self.token == token::Dot // e.g. `.5` for recovery;
- || self.token.can_begin_literal_or_bool() // e.g. `42`.
- || self.token.is_whole_expr()
- }
-
- // Helper function to decide whether to parse as ident binding
- // or to try to do something more complex like range patterns.
- fn parse_as_ident(&mut self) -> bool {
- self.look_ahead(1, |t| match t.kind {
- token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) |
- token::DotDotDot | token::DotDotEq | token::DotDot |
- token::ModSep | token::Not => false,
- _ => true,
- })
- }
-
- /// Parse and throw away a parentesized comma separated
- /// sequence of patterns until `)` is reached.
- fn skip_pat_list(&mut self) -> PResult<'a, ()> {
- while !self.check(&token::CloseDelim(token::Paren)) {
- self.parse_pat(None)?;
- if !self.eat(&token::Comma) {
- return Ok(())
- }
- }
- Ok(())
- }
-
- /// A wrapper around `parse_pat` with some special error handling for the
- /// "top-level" patterns in a match arm, `for` loop, `let`, &c. (in contrast
- /// to subpatterns within such).
- fn parse_top_level_pat(&mut self) -> PResult<'a, P<Pat>> {
- let pat = self.parse_pat(None)?;
- if self.token == token::Comma {
- // An unexpected comma after a top-level pattern is a clue that the
- // user (perhaps more accustomed to some other language) forgot the
- // parentheses in what should have been a tuple pattern; return a
- // suggestion-enhanced error here rather than choking on the comma
- // later.
- let comma_span = self.token.span;
- self.bump();
- if let Err(mut err) = self.skip_pat_list() {
- // We didn't expect this to work anyway; we just wanted
- // to advance to the end of the comma-sequence so we know
- // the span to suggest parenthesizing
- err.cancel();
- }
- let seq_span = pat.span.to(self.prev_span);
- let mut err = self.struct_span_err(comma_span,
- "unexpected `,` in pattern");
- if let Ok(seq_snippet) = self.span_to_snippet(seq_span) {
- err.span_suggestion(
- seq_span,
- "try adding parentheses to match on a tuple..",
- format!("({})", seq_snippet),
- Applicability::MachineApplicable
- ).span_suggestion(
- seq_span,
- "..or a vertical bar to match on multiple alternatives",
- format!("{}", seq_snippet.replace(",", " |")),
- Applicability::MachineApplicable
- );
- }
- return Err(err);
- }
- Ok(pat)
- }
-
- /// Parses a pattern.
- pub fn parse_pat(&mut self, expected: Option<&'static str>) -> PResult<'a, P<Pat>> {
- self.parse_pat_with_range_pat(true, expected)
- }
-
- /// Parse a range-to pattern, e.g. `..X` and `..=X` for recovery.
- fn parse_pat_range_to(&mut self, re: RangeEnd, form: &str) -> PResult<'a, PatKind> {
- let lo = self.prev_span;
- let end = self.parse_pat_range_end()?;
- let range_span = lo.to(end.span);
- let begin = self.mk_expr(range_span, ExprKind::Err, ThinVec::new());
-
- self.diagnostic()
- .struct_span_err(range_span, &format!("`{}X` range patterns are not supported", form))
- .span_suggestion(
- range_span,
- "try using the minimum value for the type",
- format!("MIN{}{}", form, pprust::expr_to_string(&end)),
- Applicability::HasPlaceholders,
- )
- .emit();
-
- Ok(PatKind::Range(begin, end, respan(lo, re)))
- }
-
- /// Parse the end of a `X..Y`, `X..=Y`, or `X...Y` range pattern or recover
- /// if that end is missing treating it as `X..`, `X..=`, or `X...` respectively.
- fn parse_pat_range_end_opt(&mut self, begin: &Expr, form: &str) -> PResult<'a, P<Expr>> {
- if self.is_pat_range_end_start() {
- // Parsing e.g. `X..=Y`.
- self.parse_pat_range_end()
- } else {
- // Parsing e.g. `X..`.
- let range_span = begin.span.to(self.prev_span);
-
- self.diagnostic()
- .struct_span_err(
- range_span,
- &format!("`X{}` range patterns are not supported", form),
- )
- .span_suggestion(
- range_span,
- "try using the maximum value for the type",
- format!("{}{}MAX", pprust::expr_to_string(&begin), form),
- Applicability::HasPlaceholders,
- )
- .emit();
-
- Ok(self.mk_expr(range_span, ExprKind::Err, ThinVec::new()))
- }
- }
-
- /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are
- /// allowed).
- fn parse_pat_with_range_pat(
- &mut self,
- allow_range_pat: bool,
- expected: Option<&'static str>,
- ) -> PResult<'a, P<Pat>> {
- maybe_recover_from_interpolated_ty_qpath!(self, true);
- maybe_whole!(self, NtPat, |x| x);
-
- let lo = self.token.span;
- let pat;
- match self.token.kind {
- token::BinOp(token::And) | token::AndAnd => {
- // Parse &pat / &mut pat
- self.expect_and()?;
- let mutbl = self.parse_mutability();
- if let token::Lifetime(name) = self.token.kind {
- let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name));
- err.span_label(self.token.span, "unexpected lifetime");
- return Err(err);
- }
- let subpat = self.parse_pat_with_range_pat(false, expected)?;
- pat = PatKind::Ref(subpat, mutbl);
- }
- token::OpenDelim(token::Paren) => {
- // Parse a tuple or parenthesis pattern.
- let (fields, trailing_comma) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
-
- // Here, `(pat,)` is a tuple pattern.
- // For backward compatibility, `(..)` is a tuple pattern as well.
- pat = if fields.len() == 1 && !(trailing_comma || fields[0].is_rest()) {
- PatKind::Paren(fields.into_iter().nth(0).unwrap())
- } else {
- PatKind::Tuple(fields)
- };
- }
- token::OpenDelim(token::Bracket) => {
- // Parse `[pat, pat,...]` as a slice pattern.
- let (slice, _) = self.parse_delim_comma_seq(token::Bracket, |p| p.parse_pat(None))?;
- pat = PatKind::Slice(slice);
- }
- token::DotDot => {
- self.bump();
- pat = if self.is_pat_range_end_start() {
- // Parse `..42` for recovery.
- self.parse_pat_range_to(RangeEnd::Excluded, "..")?
- } else {
- // A rest pattern `..`.
- PatKind::Rest
- };
- }
- token::DotDotEq => {
- // Parse `..=42` for recovery.
- self.bump();
- pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotEq), "..=")?;
- }
- token::DotDotDot => {
- // Parse `...42` for recovery.
- self.bump();
- pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotDot), "...")?;
- }
- // At this point, token != &, &&, (, [
- _ => if self.eat_keyword(kw::Underscore) {
- // Parse _
- pat = PatKind::Wild;
- } else if self.eat_keyword(kw::Mut) {
- // Parse mut ident @ pat / mut ref ident @ pat
- let mutref_span = self.prev_span.to(self.token.span);
- let binding_mode = if self.eat_keyword(kw::Ref) {
- self.diagnostic()
- .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
- .span_suggestion(
- mutref_span,
- "try switching the order",
- "ref mut".into(),
- Applicability::MachineApplicable
- ).emit();
- BindingMode::ByRef(Mutability::Mutable)
- } else {
- BindingMode::ByValue(Mutability::Mutable)
- };
- pat = self.parse_pat_ident(binding_mode)?;
- } else if self.eat_keyword(kw::Ref) {
- // Parse ref ident @ pat / ref mut ident @ pat
- let mutbl = self.parse_mutability();
- pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?;
- } else if self.eat_keyword(kw::Box) {
- // Parse box pat
- let subpat = self.parse_pat_with_range_pat(false, None)?;
- pat = PatKind::Box(subpat);
- } else if self.token.is_ident() && !self.token.is_reserved_ident() &&
- self.parse_as_ident() {
- // Parse ident @ pat
- // This can give false positives and parse nullary enums,
- // they are dealt with later in resolve
- let binding_mode = BindingMode::ByValue(Mutability::Immutable);
- pat = self.parse_pat_ident(binding_mode)?;
- } else if self.token.is_path_start() {
- // Parse pattern starting with a path
- let (qself, path) = if self.eat_lt() {
- // Parse a qualified path
- let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
- (Some(qself), path)
- } else {
- // Parse an unqualified path
- (None, self.parse_path(PathStyle::Expr)?)
- };
- match self.token.kind {
- token::Not if qself.is_none() => {
- // Parse macro invocation
- self.bump();
- let (delim, tts) = self.expect_delimited_token_tree()?;
- let mac = respan(lo.to(self.prev_span), Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- });
- pat = PatKind::Mac(mac);
- }
- token::DotDotDot | token::DotDotEq | token::DotDot => {
- let (end_kind, form) = match self.token.kind {
- token::DotDot => (RangeEnd::Excluded, ".."),
- token::DotDotDot => (RangeEnd::Included(RangeSyntax::DotDotDot), "..."),
- token::DotDotEq => (RangeEnd::Included(RangeSyntax::DotDotEq), "..="),
- _ => panic!("can only parse `..`/`...`/`..=` for ranges \
- (checked above)"),
- };
- let op_span = self.token.span;
- // Parse range
- let span = lo.to(self.prev_span);
- let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new());
- self.bump();
- let end = self.parse_pat_range_end_opt(&begin, form)?;
- pat = PatKind::Range(begin, end, respan(op_span, end_kind));
- }
- token::OpenDelim(token::Brace) => {
- if qself.is_some() {
- let msg = "unexpected `{` after qualified path";
- let mut err = self.fatal(msg);
- err.span_label(self.token.span, msg);
- return Err(err);
- }
- // Parse struct pattern
- self.bump();
- let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
- e.emit();
- self.recover_stmt();
- (vec![], true)
- });
- self.bump();
- pat = PatKind::Struct(path, fields, etc);
- }
- token::OpenDelim(token::Paren) => {
- if qself.is_some() {
- let msg = "unexpected `(` after qualified path";
- let mut err = self.fatal(msg);
- err.span_label(self.token.span, msg);
- return Err(err);
- }
- // Parse tuple struct or enum pattern
- let (fields, _) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
- pat = PatKind::TupleStruct(path, fields)
- }
- _ => pat = PatKind::Path(qself, path),
- }
- } else {
- // Try to parse everything else as literal with optional minus
- match self.parse_literal_maybe_minus() {
- Ok(begin) => {
- let op_span = self.token.span;
- if self.check(&token::DotDot) || self.check(&token::DotDotEq) ||
- self.check(&token::DotDotDot) {
- let (end_kind, form) = if self.eat(&token::DotDotDot) {
- (RangeEnd::Included(RangeSyntax::DotDotDot), "...")
- } else if self.eat(&token::DotDotEq) {
- (RangeEnd::Included(RangeSyntax::DotDotEq), "..=")
- } else if self.eat(&token::DotDot) {
- (RangeEnd::Excluded, "..")
- } else {
- panic!("impossible case: we already matched \
- on a range-operator token")
- };
- let end = self.parse_pat_range_end_opt(&begin, form)?;
- pat = PatKind::Range(begin, end, respan(op_span, end_kind))
- } else {
- pat = PatKind::Lit(begin);
- }
- }
- Err(mut err) => {
- self.cancel(&mut err);
- let expected = expected.unwrap_or("pattern");
- let msg = format!(
- "expected {}, found {}",
- expected,
- self.this_token_descr(),
- );
- let mut err = self.fatal(&msg);
- err.span_label(self.token.span, format!("expected {}", expected));
- let sp = self.sess.source_map().start_point(self.token.span);
- if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) {
- self.sess.expr_parentheses_needed(&mut err, *sp, None);
- }
- return Err(err);
- }
- }
- }
- }
-
- let pat = P(Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID });
- let pat = self.maybe_recover_from_bad_qpath(pat, true)?;
-
- if !allow_range_pat {
- match pat.node {
- PatKind::Range(
- _, _, Spanned { node: RangeEnd::Included(RangeSyntax::DotDotDot), .. }
- ) => {},
- PatKind::Range(..) => {
- let mut err = self.struct_span_err(
- pat.span,
- "the range pattern here has ambiguous interpretation",
- );
- err.span_suggestion(
- pat.span,
- "add parentheses to clarify the precedence",
- format!("({})", pprust::pat_to_string(&pat)),
- // "ambiguous interpretation" implies that we have to be guessing
- Applicability::MaybeIncorrect
- );
- return Err(err);
- }
- _ => {}
- }
- }
-
- Ok(pat)
- }
-
- /// Parses `ident` or `ident @ pat`.
- /// used by the copy foo and ref foo patterns to give a good
- /// error message when parsing mistakes like `ref foo(a, b)`.
- fn parse_pat_ident(&mut self,
- binding_mode: ast::BindingMode)
- -> PResult<'a, PatKind> {
- let ident = self.parse_ident()?;
- let sub = if self.eat(&token::At) {
- Some(self.parse_pat(Some("binding pattern"))?)
- } else {
- None
- };
-
- // just to be friendly, if they write something like
- // ref Some(i)
- // we end up here with ( as the current token. This shortly
- // leads to a parse error. Note that if there is no explicit
- // binding mode then we do not end up here, because the lookahead
- // will direct us over to parse_enum_variant()
- if self.token == token::OpenDelim(token::Paren) {
- return Err(self.span_fatal(
- self.prev_span,
- "expected identifier, found enum pattern"))
- }
-
- Ok(PatKind::Ident(binding_mode, ident, sub))
- }
-
- /// Parses a local variable declaration.
- fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
- let lo = self.prev_span;
- let pat = self.parse_top_level_pat()?;
-
- let (err, ty) = if self.eat(&token::Colon) {
- // Save the state of the parser before parsing type normally, in case there is a `:`
- // instead of an `=` typo.
- let parser_snapshot_before_type = self.clone();
- let colon_sp = self.prev_span;
- match self.parse_ty() {
- Ok(ty) => (None, Some(ty)),
- Err(mut err) => {
- // Rewind to before attempting to parse the type and continue parsing
- let parser_snapshot_after_type = self.clone();
- mem::replace(self, parser_snapshot_before_type);
-
- let snippet = self.span_to_snippet(pat.span).unwrap();
- err.span_label(pat.span, format!("while parsing the type for `{}`", snippet));
- (Some((parser_snapshot_after_type, colon_sp, err)), None)
- }
- }
- } else {
- (None, None)
- };
- let init = match (self.parse_initializer(err.is_some()), err) {
- (Ok(init), None) => { // init parsed, ty parsed
- init
- }
- (Ok(init), Some((_, colon_sp, mut err))) => { // init parsed, ty error
- // Could parse the type as if it were the initializer, it is likely there was a
- // typo in the code: `:` instead of `=`. Add suggestion and emit the error.
- err.span_suggestion_short(
- colon_sp,
- "use `=` if you meant to assign",
- "=".to_string(),
- Applicability::MachineApplicable
- );
- err.emit();
- // As this was parsed successfully, continue as if the code has been fixed for the
- // rest of the file. It will still fail due to the emitted error, but we avoid
- // extra noise.
- init
- }
- (Err(mut init_err), Some((snapshot, _, ty_err))) => { // init error, ty error
- init_err.cancel();
- // Couldn't parse the type nor the initializer, only raise the type error and
- // return to the parser state before parsing the type as the initializer.
- // let x: <parse_error>;
- mem::replace(self, snapshot);
- return Err(ty_err);
- }
- (Err(err), None) => { // init error, ty parsed
- // Couldn't parse the initializer and we're not attempting to recover a failed
- // parse of the type, return the error.
- return Err(err);
- }
- };
- let hi = if self.token == token::Semi {
- self.token.span
- } else {
- self.prev_span
- };
- Ok(P(ast::Local {
- ty,
- pat,
- init,
- id: ast::DUMMY_NODE_ID,
- span: lo.to(hi),
- attrs,
- }))
- }
-
- /// Parses a structure field.
- fn parse_name_and_ty(&mut self,
- lo: Span,
- vis: Visibility,
- attrs: Vec<Attribute>)
- -> PResult<'a, StructField> {
- let name = self.parse_ident()?;
- self.expect(&token::Colon)?;
- let ty = self.parse_ty()?;
- Ok(StructField {
- span: lo.to(self.prev_span),
- ident: Some(name),
- vis,
- id: ast::DUMMY_NODE_ID,
- ty,
- attrs,
- })
- }
-
- /// Emits an expected-item-after-attributes error.
- fn expected_item_err(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
- let message = match attrs.last() {
- Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment",
- _ => "expected item after attributes",
- };
-
- let mut err = self.diagnostic().struct_span_err(self.prev_span, message);
- if attrs.last().unwrap().is_sugared_doc {
- err.span_label(self.prev_span, "this doc comment doesn't document anything");
- }
- Err(err)
- }
-
- /// Parse a statement. This stops just before trailing semicolons on everything but items.
- /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
- pub fn parse_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
- Ok(self.parse_stmt_(true))
- }
-
- fn parse_stmt_(&mut self, macro_legacy_warnings: bool) -> Option<Stmt> {
- self.parse_stmt_without_recovery(macro_legacy_warnings).unwrap_or_else(|mut e| {
- e.emit();
- self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
- None
- })
- }
-
- fn is_async_block(&self) -> bool {
- self.token.is_keyword(kw::Async) &&
- (
- ( // `async move {`
- self.is_keyword_ahead(1, &[kw::Move]) &&
- self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))
- ) || ( // `async {`
- self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace))
- )
- )
- }
-
- fn is_async_fn(&self) -> bool {
- self.token.is_keyword(kw::Async) &&
- self.is_keyword_ahead(1, &[kw::Fn])
- }
-
- fn is_do_catch_block(&self) -> bool {
- self.token.is_keyword(kw::Do) &&
- self.is_keyword_ahead(1, &[kw::Catch]) &&
- self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) &&
- !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
- }
-
- fn is_try_block(&self) -> bool {
- self.token.is_keyword(kw::Try) &&
- self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) &&
- self.token.span.rust_2018() &&
- // prevent `while try {} {}`, `if try {} {} else {}`, etc.
- !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
- }
-
- fn is_union_item(&self) -> bool {
- self.token.is_keyword(kw::Union) &&
- self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
- }
-
- fn is_crate_vis(&self) -> bool {
- self.token.is_keyword(kw::Crate) && self.look_ahead(1, |t| t != &token::ModSep)
- }
-
- fn is_auto_trait_item(&self) -> bool {
- // auto trait
- (self.token.is_keyword(kw::Auto) &&
- self.is_keyword_ahead(1, &[kw::Trait]))
- || // unsafe auto trait
- (self.token.is_keyword(kw::Unsafe) &&
- self.is_keyword_ahead(1, &[kw::Auto]) &&
- self.is_keyword_ahead(2, &[kw::Trait]))
- }
-
- fn eat_macro_def(&mut self, attrs: &[Attribute], vis: &Visibility, lo: Span)
- -> PResult<'a, Option<P<Item>>> {
- let token_lo = self.token.span;
- let (ident, def) = if self.eat_keyword(kw::Macro) {
- let ident = self.parse_ident()?;
- let tokens = if self.check(&token::OpenDelim(token::Brace)) {
- match self.parse_token_tree() {
- TokenTree::Delimited(_, _, tts) => tts,
- _ => unreachable!(),
- }
- } else if self.check(&token::OpenDelim(token::Paren)) {
- let args = self.parse_token_tree();
- let body = if self.check(&token::OpenDelim(token::Brace)) {
- self.parse_token_tree()
- } else {
- self.unexpected()?;
- unreachable!()
- };
- TokenStream::new(vec![
- args.into(),
- TokenTree::token(token::FatArrow, token_lo.to(self.prev_span)).into(),
- body.into(),
- ])
- } else {
- self.unexpected()?;
- unreachable!()
- };
-
- (ident, ast::MacroDef { tokens: tokens.into(), legacy: false })
- } else if self.check_keyword(sym::macro_rules) &&
- self.look_ahead(1, |t| *t == token::Not) &&
- self.look_ahead(2, |t| t.is_ident()) {
- let prev_span = self.prev_span;
- self.complain_if_pub_macro(&vis.node, prev_span);
- self.bump();
- self.bump();
-
- let ident = self.parse_ident()?;
- let (delim, tokens) = self.expect_delimited_token_tree()?;
- if delim != MacDelimiter::Brace && !self.eat(&token::Semi) {
- self.report_invalid_macro_expansion_item();
- }
-
- (ident, ast::MacroDef { tokens, legacy: true })
- } else {
- return Ok(None);
- };
-
- let span = lo.to(self.prev_span);
- Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec())))
- }
-
- fn parse_stmt_without_recovery(
- &mut self,
- macro_legacy_warnings: bool,
- ) -> PResult<'a, Option<Stmt>> {
- maybe_whole!(self, NtStmt, |x| Some(x));
-
- let attrs = self.parse_outer_attributes()?;
- let lo = self.token.span;
-
- Ok(Some(if self.eat_keyword(kw::Let) {
- Stmt {
- id: ast::DUMMY_NODE_ID,
- node: StmtKind::Local(self.parse_local(attrs.into())?),
- span: lo.to(self.prev_span),
- }
- } else if let Some(macro_def) = self.eat_macro_def(
- &attrs,
- &source_map::respan(lo, VisibilityKind::Inherited),
- lo,
- )? {
- Stmt {
- id: ast::DUMMY_NODE_ID,
- node: StmtKind::Item(macro_def),
- span: lo.to(self.prev_span),
- }
- // Starts like a simple path, being careful to avoid contextual keywords
- // such as a union items, item with `crate` visibility or auto trait items.
- // Our goal here is to parse an arbitrary path `a::b::c` but not something that starts
- // like a path (1 token), but it fact not a path.
- // `union::b::c` - path, `union U { ... }` - not a path.
- // `crate::b::c` - path, `crate struct S;` - not a path.
- } else if self.token.is_path_start() &&
- !self.token.is_qpath_start() &&
- !self.is_union_item() &&
- !self.is_crate_vis() &&
- !self.is_auto_trait_item() &&
- !self.is_async_fn() {
- let path = self.parse_path(PathStyle::Expr)?;
-
- if !self.eat(&token::Not) {
- let expr = if self.check(&token::OpenDelim(token::Brace)) {
- self.parse_struct_expr(lo, path, ThinVec::new())?
- } else {
- let hi = self.prev_span;
- self.mk_expr(lo.to(hi), ExprKind::Path(None, path), ThinVec::new())
- };
-
- let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
- let expr = this.parse_dot_or_call_expr_with(expr, lo, attrs.into())?;
- this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
- })?;
-
- return Ok(Some(Stmt {
- id: ast::DUMMY_NODE_ID,
- node: StmtKind::Expr(expr),
- span: lo.to(self.prev_span),
- }));
- }
-
- let (delim, tts) = self.expect_delimited_token_tree()?;
- let hi = self.prev_span;
-
- let style = if delim == MacDelimiter::Brace {
- MacStmtStyle::Braces
- } else {
- MacStmtStyle::NoBraces
- };
-
- let mac = respan(lo.to(hi), Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- });
- let node = if delim == MacDelimiter::Brace ||
- self.token == token::Semi || self.token == token::Eof {
- StmtKind::Mac(P((mac, style, attrs.into())))
- }
- // We used to incorrectly stop parsing macro-expanded statements here.
- // If the next token will be an error anyway but could have parsed with the
- // earlier behavior, stop parsing here and emit a warning to avoid breakage.
- else if macro_legacy_warnings &&
- self.token.can_begin_expr() &&
- match self.token.kind {
- // These can continue an expression, so we can't stop parsing and warn.
- token::OpenDelim(token::Paren) | token::OpenDelim(token::Bracket) |
- token::BinOp(token::Minus) | token::BinOp(token::Star) |
- token::BinOp(token::And) | token::BinOp(token::Or) |
- token::AndAnd | token::OrOr |
- token::DotDot | token::DotDotDot | token::DotDotEq => false,
- _ => true,
- } {
- self.warn_missing_semicolon();
- StmtKind::Mac(P((mac, style, attrs.into())))
- } else {
- let e = self.mk_expr(mac.span, ExprKind::Mac(mac), ThinVec::new());
- let e = self.maybe_recover_from_bad_qpath(e, true)?;
- let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
- let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
- StmtKind::Expr(e)
- };
- Stmt {
- id: ast::DUMMY_NODE_ID,
- span: lo.to(hi),
- node,
- }
- } else {
- // FIXME: Bad copy of attrs
- let old_directory_ownership =
- mem::replace(&mut self.directory.ownership, DirectoryOwnership::UnownedViaBlock);
- let item = self.parse_item_(attrs.clone(), false, true)?;
- self.directory.ownership = old_directory_ownership;
-
- match item {
- Some(i) => Stmt {
- id: ast::DUMMY_NODE_ID,
- span: lo.to(i.span),
- node: StmtKind::Item(i),
- },
- None => {
- let unused_attrs = |attrs: &[Attribute], s: &mut Self| {
- if !attrs.is_empty() {
- if s.prev_token_kind == PrevTokenKind::DocComment {
- s.span_fatal_err(s.prev_span, Error::UselessDocComment).emit();
- } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
- s.span_err(
- s.token.span, "expected statement after outer attribute"
- );
- }
- }
- };
-
- // Do not attempt to parse an expression if we're done here.
- if self.token == token::Semi {
- unused_attrs(&attrs, self);
- self.bump();
- return Ok(None);
- }
-
- if self.token == token::CloseDelim(token::Brace) {
- unused_attrs(&attrs, self);
- return Ok(None);
- }
-
- // Remainder are line-expr stmts.
- let e = self.parse_expr_res(
- Restrictions::STMT_EXPR, Some(attrs.into()))?;
- Stmt {
- id: ast::DUMMY_NODE_ID,
- span: lo.to(e.span),
- node: StmtKind::Expr(e),
- }
- }
- }
- }))
- }
-
- /// Checks if this expression is a successfully parsed statement.
- fn expr_is_complete(&self, e: &Expr) -> bool {
- self.restrictions.contains(Restrictions::STMT_EXPR) &&
- !classify::expr_requires_semi_to_be_stmt(e)
- }
-
- /// Parses a block. No inner attributes are allowed.
- pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
- maybe_whole!(self, NtBlock, |x| x);
-
- let lo = self.token.span;
-
- if !self.eat(&token::OpenDelim(token::Brace)) {
- let sp = self.token.span;
- let tok = self.this_token_descr();
- let mut e = self.span_fatal(sp, &format!("expected `{{`, found {}", tok));
- let do_not_suggest_help =
- self.token.is_keyword(kw::In) || self.token == token::Colon;
-
- if self.token.is_ident_named(sym::and) {
- e.span_suggestion_short(
- self.token.span,
- "use `&&` instead of `and` for the boolean operator",
- "&&".to_string(),
- Applicability::MaybeIncorrect,
- );
- }
- if self.token.is_ident_named(sym::or) {
- e.span_suggestion_short(
- self.token.span,
- "use `||` instead of `or` for the boolean operator",
- "||".to_string(),
- Applicability::MaybeIncorrect,
- );
- }
-
- // Check to see if the user has written something like
- //
- // if (cond)
- // bar;
- //
- // Which is valid in other languages, but not Rust.
- match self.parse_stmt_without_recovery(false) {
- Ok(Some(stmt)) => {
- if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
- || do_not_suggest_help {
- // if the next token is an open brace (e.g., `if a b {`), the place-
- // inside-a-block suggestion would be more likely wrong than right
- e.span_label(sp, "expected `{`");
- return Err(e);
- }
- let mut stmt_span = stmt.span;
- // expand the span to include the semicolon, if it exists
- if self.eat(&token::Semi) {
- stmt_span = stmt_span.with_hi(self.prev_span.hi());
- }
- if let Ok(snippet) = self.span_to_snippet(stmt_span) {
- e.span_suggestion(
- stmt_span,
- "try placing this code inside a block",
- format!("{{ {} }}", snippet),
- // speculative, has been misleading in the past (#46836)
- Applicability::MaybeIncorrect,
- );
- }
- }
- Err(mut e) => {
- self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
- self.cancel(&mut e);
- }
- _ => ()
- }
- e.span_label(sp, "expected `{`");
- return Err(e);
- }
-
- self.parse_block_tail(lo, BlockCheckMode::Default)
- }
-
- /// Parses a block. Inner attributes are allowed.
- crate fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
- maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
-
- let lo = self.token.span;
- self.expect(&token::OpenDelim(token::Brace))?;
- Ok((self.parse_inner_attributes()?,
- self.parse_block_tail(lo, BlockCheckMode::Default)?))
- }
-
- /// Parses the rest of a block expression or function body.
- /// Precondition: already parsed the '{'.
- fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> {
- let mut stmts = vec![];
- while !self.eat(&token::CloseDelim(token::Brace)) {
- if self.token == token::Eof {
- break;
- }
- let stmt = match self.parse_full_stmt(false) {
- Err(mut err) => {
- err.emit();
- self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
- Some(Stmt {
- id: ast::DUMMY_NODE_ID,
- node: StmtKind::Expr(DummyResult::raw_expr(self.token.span, true)),
- span: self.token.span,
- })
- }
- Ok(stmt) => stmt,
- };
- if let Some(stmt) = stmt {
- stmts.push(stmt);
- } else {
- // Found only `;` or `}`.
- continue;
- };
- }
- Ok(P(ast::Block {
- stmts,
- id: ast::DUMMY_NODE_ID,
- rules: s,
- span: lo.to(self.prev_span),
- }))
- }
-
- /// Parses a statement, including the trailing semicolon.
- crate fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
- // skip looking for a trailing semicolon when we have an interpolated statement
- maybe_whole!(self, NtStmt, |x| Some(x));
-
- let mut stmt = match self.parse_stmt_without_recovery(macro_legacy_warnings)? {
- Some(stmt) => stmt,
- None => return Ok(None),
- };
-
- match stmt.node {
- StmtKind::Expr(ref expr) if self.token != token::Eof => {
- // expression without semicolon
- if classify::expr_requires_semi_to_be_stmt(expr) {
- // Just check for errors and recover; do not eat semicolon yet.
- if let Err(mut e) =
- self.expect_one_of(&[], &[token::Semi, token::CloseDelim(token::Brace)])
- {
- e.emit();
- self.recover_stmt();
- // Don't complain about type errors in body tail after parse error (#57383).
- let sp = expr.span.to(self.prev_span);
- stmt.node = StmtKind::Expr(DummyResult::raw_expr(sp, true));
- }
- }
- }
- StmtKind::Local(..) => {
- // We used to incorrectly allow a macro-expanded let statement to lack a semicolon.
- if macro_legacy_warnings && self.token != token::Semi {
- self.warn_missing_semicolon();
- } else {
- self.expect_one_of(&[], &[token::Semi])?;
- }
- }
- _ => {}
- }
-
- if self.eat(&token::Semi) {
- stmt = stmt.add_trailing_semicolon();
- }
- stmt.span = stmt.span.to(self.prev_span);
- Ok(Some(stmt))
- }
-
- fn warn_missing_semicolon(&self) {
- self.diagnostic().struct_span_warn(self.token.span, {
- &format!("expected `;`, found {}", self.this_token_descr())
- }).note({
- "This was erroneously allowed and will become a hard error in a future release"
- }).emit();
- }
-
- fn err_dotdotdot_syntax(&self, span: Span) {
- self.diagnostic().struct_span_err(span, {
- "unexpected token: `...`"
- }).span_suggestion(
- span, "use `..` for an exclusive range", "..".to_owned(),
- Applicability::MaybeIncorrect
- ).span_suggestion(
- span, "or `..=` for an inclusive range", "..=".to_owned(),
- Applicability::MaybeIncorrect
- ).emit();
- }
-
- /// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`.
- ///
- /// ```
- /// BOUND = TY_BOUND | LT_BOUND
- /// LT_BOUND = LIFETIME (e.g., `'a`)
- /// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
- /// TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g., `?for<'a: 'b> m::Trait<'a>`)
- /// ```
- fn parse_generic_bounds_common(&mut self,
- allow_plus: bool,
- colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
- let mut bounds = Vec::new();
- let mut negative_bounds = Vec::new();
- let mut last_plus_span = None;
- let mut was_negative = false;
- loop {
- // This needs to be synchronized with `TokenKind::can_begin_bound`.
- let is_bound_start = self.check_path() || self.check_lifetime() ||
- self.check(&token::Not) || // used for error reporting only
- self.check(&token::Question) ||
- self.check_keyword(kw::For) ||
- self.check(&token::OpenDelim(token::Paren));
- if is_bound_start {
- let lo = self.token.span;
- let has_parens = self.eat(&token::OpenDelim(token::Paren));
- let inner_lo = self.token.span;
- let is_negative = self.eat(&token::Not);
- let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
- if self.token.is_lifetime() {
- if let Some(question_span) = question {
- self.span_err(question_span,
- "`?` may only modify trait bounds, not lifetime bounds");
- }
- bounds.push(GenericBound::Outlives(self.expect_lifetime()));
- if has_parens {
- let inner_span = inner_lo.to(self.prev_span);
- self.expect(&token::CloseDelim(token::Paren))?;
- let mut err = self.struct_span_err(
- lo.to(self.prev_span),
- "parenthesized lifetime bounds are not supported"
- );
- if let Ok(snippet) = self.span_to_snippet(inner_span) {
- err.span_suggestion_short(
- lo.to(self.prev_span),
- "remove the parentheses",
- snippet.to_owned(),
- Applicability::MachineApplicable
- );
- }
- err.emit();
- }
- } else {
- let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
- let path = self.parse_path(PathStyle::Type)?;
- if has_parens {
- self.expect(&token::CloseDelim(token::Paren))?;
- }
- let poly_span = lo.to(self.prev_span);
- if is_negative {
- was_negative = true;
- if let Some(sp) = last_plus_span.or(colon_span) {
- negative_bounds.push(sp.to(poly_span));
- }
- } else {
- let poly_trait = PolyTraitRef::new(lifetime_defs, path, poly_span);
- let modifier = if question.is_some() {
- TraitBoundModifier::Maybe
- } else {
- TraitBoundModifier::None
- };
- bounds.push(GenericBound::Trait(poly_trait, modifier));
- }
- }
- } else {
- break
- }
-
- if !allow_plus || !self.eat_plus() {
- break
- } else {
- last_plus_span = Some(self.prev_span);
- }
- }
-
- if !negative_bounds.is_empty() || was_negative {
- let plural = negative_bounds.len() > 1;
- let last_span = negative_bounds.last().map(|sp| *sp);
- let mut err = self.struct_span_err(
- negative_bounds,
- "negative trait bounds are not supported",
- );
- if let Some(sp) = last_span {
- err.span_label(sp, "negative trait bounds are not supported");
- }
- if let Some(bound_list) = colon_span {
- let bound_list = bound_list.to(self.prev_span);
- let mut new_bound_list = String::new();
- if !bounds.is_empty() {
- let mut snippets = bounds.iter().map(|bound| bound.span())
- .map(|span| self.span_to_snippet(span));
- while let Some(Ok(snippet)) = snippets.next() {
- new_bound_list.push_str(" + ");
- new_bound_list.push_str(&snippet);
- }
- new_bound_list = new_bound_list.replacen(" +", ":", 1);
- }
- err.span_suggestion_hidden(
- bound_list,
- &format!("remove the trait bound{}", if plural { "s" } else { "" }),
- new_bound_list,
- Applicability::MachineApplicable,
- );
- }
- err.emit();
- }
-
- return Ok(bounds);
- }
-
- crate fn parse_generic_bounds(&mut self,
- colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
- self.parse_generic_bounds_common(true, colon_span)
- }
-
- /// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
- ///
- /// ```
- /// BOUND = LT_BOUND (e.g., `'a`)
- /// ```
- fn parse_lt_param_bounds(&mut self) -> GenericBounds {
- let mut lifetimes = Vec::new();
- while self.check_lifetime() {
- lifetimes.push(ast::GenericBound::Outlives(self.expect_lifetime()));
-
- if !self.eat_plus() {
- break
- }
- }
- lifetimes
- }
-
- /// Matches `typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?`.
- fn parse_ty_param(&mut self,
- preceding_attrs: Vec<Attribute>)
- -> PResult<'a, GenericParam> {
- let ident = self.parse_ident()?;
-
- // Parse optional colon and param bounds.
- let bounds = if self.eat(&token::Colon) {
- self.parse_generic_bounds(Some(self.prev_span))?
- } else {
- Vec::new()
- };
-
- let default = if self.eat(&token::Eq) {
- Some(self.parse_ty()?)
- } else {
- None
- };
-
- Ok(GenericParam {
- ident,
- id: ast::DUMMY_NODE_ID,
- attrs: preceding_attrs.into(),
- bounds,
- kind: GenericParamKind::Type {
- default,
- }
- })
- }
-
- /// Parses the following grammar:
- ///
- /// TraitItemAssocTy = Ident ["<"...">"] [":" [GenericBounds]] ["where" ...] ["=" Ty]
- fn parse_trait_item_assoc_ty(&mut self)
- -> PResult<'a, (Ident, TraitItemKind, ast::Generics)> {
- let ident = self.parse_ident()?;
- let mut generics = self.parse_generics()?;
-
- // Parse optional colon and param bounds.
- let bounds = if self.eat(&token::Colon) {
- self.parse_generic_bounds(None)?
- } else {
- Vec::new()
- };
- generics.where_clause = self.parse_where_clause()?;
-
- let default = if self.eat(&token::Eq) {
- Some(self.parse_ty()?)
- } else {
- None
- };
- self.expect(&token::Semi)?;
-
- Ok((ident, TraitItemKind::Type(bounds, default), generics))
- }
-
- fn parse_const_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> {
- self.expect_keyword(kw::Const)?;
- let ident = self.parse_ident()?;
- self.expect(&token::Colon)?;
- let ty = self.parse_ty()?;
-
- Ok(GenericParam {
- ident,
- id: ast::DUMMY_NODE_ID,
- attrs: preceding_attrs.into(),
- bounds: Vec::new(),
- kind: GenericParamKind::Const {
- ty,
- }
- })
- }
-
- /// Parses a (possibly empty) list of lifetime and type parameters, possibly including
- /// a trailing comma and erroneous trailing attributes.
- crate fn parse_generic_params(&mut self) -> PResult<'a, Vec<ast::GenericParam>> {
- let mut params = Vec::new();
- loop {
- let attrs = self.parse_outer_attributes()?;
- if self.check_lifetime() {
- let lifetime = self.expect_lifetime();
- // Parse lifetime parameter.
- let bounds = if self.eat(&token::Colon) {
- self.parse_lt_param_bounds()
- } else {
- Vec::new()
- };
- params.push(ast::GenericParam {
- ident: lifetime.ident,
- id: lifetime.id,
- attrs: attrs.into(),
- bounds,
- kind: ast::GenericParamKind::Lifetime,
- });
- } else if self.check_keyword(kw::Const) {
- // Parse const parameter.
- params.push(self.parse_const_param(attrs)?);
- } else if self.check_ident() {
- // Parse type parameter.
- params.push(self.parse_ty_param(attrs)?);
- } else {
- // Check for trailing attributes and stop parsing.
- if !attrs.is_empty() {
- if !params.is_empty() {
- self.struct_span_err(
- attrs[0].span,
- &format!("trailing attribute after generic parameter"),
- )
- .span_label(attrs[0].span, "attributes must go before parameters")
- .emit();
- } else {
- self.struct_span_err(
- attrs[0].span,
- &format!("attribute without generic parameters"),
- )
- .span_label(
- attrs[0].span,
- "attributes are only permitted when preceding parameters",
- )
- .emit();
- }
- }
- break
- }
-
- if !self.eat(&token::Comma) {
- break
- }
- }
- Ok(params)
- }
-
- /// Parses a set of optional generic type parameter declarations. Where
- /// clauses are not parsed here, and must be added later via
- /// `parse_where_clause()`.
- ///
- /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
- /// | ( < lifetimes , typaramseq ( , )? > )
- /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
- fn parse_generics(&mut self) -> PResult<'a, ast::Generics> {
- let span_lo = self.token.span;
- let (params, span) = if self.eat_lt() {
- let params = self.parse_generic_params()?;
- self.expect_gt()?;
- (params, span_lo.to(self.prev_span))
- } else {
- (vec![], self.prev_span.between(self.token.span))
- };
- Ok(ast::Generics {
- params,
- where_clause: WhereClause {
- predicates: Vec::new(),
- span: DUMMY_SP,
- },
- span,
- })
- }
-
- /// Parses generic args (within a path segment) with recovery for extra leading angle brackets.
- /// For the purposes of understanding the parsing logic of generic arguments, this function
- /// can be thought of being the same as just calling `self.parse_generic_args()` if the source
- /// had the correct amount of leading angle brackets.
- ///
- /// ```ignore (diagnostics)
- /// bar::<<<<T as Foo>::Output>();
- /// ^^ help: remove extra angle brackets
- /// ```
- fn parse_generic_args_with_leaning_angle_bracket_recovery(
- &mut self,
- style: PathStyle,
- lo: Span,
- ) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> {
- // We need to detect whether there are extra leading left angle brackets and produce an
- // appropriate error and suggestion. This cannot be implemented by looking ahead at
- // upcoming tokens for a matching `>` character - if there are unmatched `<` tokens
- // then there won't be matching `>` tokens to find.
- //
- // To explain how this detection works, consider the following example:
- //
- // ```ignore (diagnostics)
- // bar::<<<<T as Foo>::Output>();
- // ^^ help: remove extra angle brackets
- // ```
- //
- // Parsing of the left angle brackets starts in this function. We start by parsing the
- // `<` token (incrementing the counter of unmatched angle brackets on `Parser` via
- // `eat_lt`):
- //
- // *Upcoming tokens:* `<<<<T as Foo>::Output>;`
- // *Unmatched count:* 1
- // *`parse_path_segment` calls deep:* 0
- //
- // This has the effect of recursing as this function is called if a `<` character
- // is found within the expected generic arguments:
- //
- // *Upcoming tokens:* `<<<T as Foo>::Output>;`
- // *Unmatched count:* 2
- // *`parse_path_segment` calls deep:* 1
- //
- // Eventually we will have recursed until having consumed all of the `<` tokens and
- // this will be reflected in the count:
- //
- // *Upcoming tokens:* `T as Foo>::Output>;`
- // *Unmatched count:* 4
- // `parse_path_segment` calls deep:* 3
- //
- // The parser will continue until reaching the first `>` - this will decrement the
- // unmatched angle bracket count and return to the parent invocation of this function
- // having succeeded in parsing:
- //
- // *Upcoming tokens:* `::Output>;`
- // *Unmatched count:* 3
- // *`parse_path_segment` calls deep:* 2
- //
- // This will continue until the next `>` character which will also return successfully
- // to the parent invocation of this function and decrement the count:
- //
- // *Upcoming tokens:* `;`
- // *Unmatched count:* 2
- // *`parse_path_segment` calls deep:* 1
- //
- // At this point, this function will expect to find another matching `>` character but
- // won't be able to and will return an error. This will continue all the way up the
- // call stack until the first invocation:
- //
- // *Upcoming tokens:* `;`
- // *Unmatched count:* 2
- // *`parse_path_segment` calls deep:* 0
- //
- // In doing this, we have managed to work out how many unmatched leading left angle
- // brackets there are, but we cannot recover as the unmatched angle brackets have
- // already been consumed. To remedy this, we keep a snapshot of the parser state
- // before we do the above. We can then inspect whether we ended up with a parsing error
- // and unmatched left angle brackets and if so, restore the parser state before we
- // consumed any `<` characters to emit an error and consume the erroneous tokens to
- // recover by attempting to parse again.
- //
- // In practice, the recursion of this function is indirect and there will be other
- // locations that consume some `<` characters - as long as we update the count when
- // this happens, it isn't an issue.
-
- let is_first_invocation = style == PathStyle::Expr;
- // Take a snapshot before attempting to parse - we can restore this later.
- let snapshot = if is_first_invocation {
- Some(self.clone())
- } else {
- None
- };
-
- debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
- match self.parse_generic_args() {
- Ok(value) => Ok(value),
- Err(ref mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
- // Cancel error from being unable to find `>`. We know the error
- // must have been this due to a non-zero unmatched angle bracket
- // count.
- e.cancel();
-
- // Swap `self` with our backup of the parser state before attempting to parse
- // generic arguments.
- let snapshot = mem::replace(self, snapshot.unwrap());
-
- debug!(
- "parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
- snapshot.count={:?}",
- snapshot.unmatched_angle_bracket_count,
- );
-
- // Eat the unmatched angle brackets.
- for _ in 0..snapshot.unmatched_angle_bracket_count {
- self.eat_lt();
- }
-
- // Make a span over ${unmatched angle bracket count} characters.
- let span = lo.with_hi(
- lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
- );
- let plural = snapshot.unmatched_angle_bracket_count > 1;
- self.diagnostic()
- .struct_span_err(
- span,
- &format!(
- "unmatched angle bracket{}",
- if plural { "s" } else { "" }
- ),
- )
- .span_suggestion(
- span,
- &format!(
- "remove extra angle bracket{}",
- if plural { "s" } else { "" }
- ),
- String::new(),
- Applicability::MachineApplicable,
- )
- .emit();
-
- // Try again without unmatched angle bracket characters.
- self.parse_generic_args()
- },
- Err(e) => Err(e),
- }
- }
-
- /// Parses (possibly empty) list of lifetime and type arguments and associated type bindings,
- /// possibly including trailing comma.
- fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> {
- let mut args = Vec::new();
- let mut constraints = Vec::new();
- let mut misplaced_assoc_ty_constraints: Vec<Span> = Vec::new();
- let mut assoc_ty_constraints: Vec<Span> = Vec::new();
-
- let args_lo = self.token.span;
-
- loop {
- if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
- // Parse lifetime argument.
- args.push(GenericArg::Lifetime(self.expect_lifetime()));
- misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
- } else if self.check_ident() && self.look_ahead(1,
- |t| t == &token::Eq || t == &token::Colon) {
- // Parse associated type constraint.
- let lo = self.token.span;
- let ident = self.parse_ident()?;
- let kind = if self.eat(&token::Eq) {
- AssocTyConstraintKind::Equality {
- ty: self.parse_ty()?,
- }
- } else if self.eat(&token::Colon) {
- AssocTyConstraintKind::Bound {
- bounds: self.parse_generic_bounds(Some(self.prev_span))?,
- }
- } else {
- unreachable!();
- };
- let span = lo.to(self.prev_span);
- constraints.push(AssocTyConstraint {
- id: ast::DUMMY_NODE_ID,
- ident,
- kind,
- span,
- });
- assoc_ty_constraints.push(span);
- } else if self.check_const_arg() {
- // Parse const argument.
- let expr = if let token::OpenDelim(token::Brace) = self.token.kind {
- self.parse_block_expr(
- None, self.token.span, BlockCheckMode::Default, ThinVec::new()
- )?
- } else if self.token.is_ident() {
- // FIXME(const_generics): to distinguish between idents for types and consts,
- // we should introduce a GenericArg::Ident in the AST and distinguish when
- // lowering to the HIR. For now, idents for const args are not permitted.
- if self.token.is_keyword(kw::True) || self.token.is_keyword(kw::False) {
- self.parse_literal_maybe_minus()?
- } else {
- return Err(
- self.fatal("identifiers may currently not be used for const generics")
- );
- }
- } else {
- self.parse_literal_maybe_minus()?
- };
- let value = AnonConst {
- id: ast::DUMMY_NODE_ID,
- value: expr,
- };
- args.push(GenericArg::Const(value));
- misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
- } else if self.check_type() {
- // Parse type argument.
- args.push(GenericArg::Type(self.parse_ty()?));
- misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
- } else {
- break
- }
-
- if !self.eat(&token::Comma) {
- break
- }
- }
-
- // FIXME: we would like to report this in ast_validation instead, but we currently do not
- // preserve ordering of generic parameters with respect to associated type binding, so we
- // lose that information after parsing.
- if misplaced_assoc_ty_constraints.len() > 0 {
- let mut err = self.struct_span_err(
- args_lo.to(self.prev_span),
- "associated type bindings must be declared after generic parameters",
- );
- for span in misplaced_assoc_ty_constraints {
- err.span_label(
- span,
- "this associated type binding should be moved after the generic parameters",
- );
- }
- err.emit();
- }
-
- Ok((args, constraints))
- }
-
- /// Parses an optional where-clause and places it in `generics`.
- ///
- /// ```ignore (only-for-syntax-highlight)
- /// where T : Trait<U, V> + 'b, 'a : 'b
- /// ```
- fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> {
- let mut where_clause = WhereClause {
- predicates: Vec::new(),
- span: self.prev_span.to(self.prev_span),
- };
-
- if !self.eat_keyword(kw::Where) {
- return Ok(where_clause);
- }
- let lo = self.prev_span;
-
- // We are considering adding generics to the `where` keyword as an alternative higher-rank
- // parameter syntax (as in `where<'a>` or `where<T>`. To avoid that being a breaking
- // change we parse those generics now, but report an error.
- if self.choose_generics_over_qpath() {
- let generics = self.parse_generics()?;
- self.struct_span_err(
- generics.span,
- "generic parameters on `where` clauses are reserved for future use",
- )
- .span_label(generics.span, "currently unsupported")
- .emit();
- }
-
- loop {
- let lo = self.token.span;
- if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
- let lifetime = self.expect_lifetime();
- // Bounds starting with a colon are mandatory, but possibly empty.
- self.expect(&token::Colon)?;
- let bounds = self.parse_lt_param_bounds();
- where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
- ast::WhereRegionPredicate {
- span: lo.to(self.prev_span),
- lifetime,
- bounds,
- }
- ));
- } else if self.check_type() {
- // Parse optional `for<'a, 'b>`.
- // This `for` is parsed greedily and applies to the whole predicate,
- // the bounded type can have its own `for` applying only to it.
- // Examples:
- // * `for<'a> Trait1<'a>: Trait2<'a /* ok */>`
- // * `(for<'a> Trait1<'a>): Trait2<'a /* not ok */>`
- // * `for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /* ok */, 'b /* not ok */>`
- let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
-
- // Parse type with mandatory colon and (possibly empty) bounds,
- // or with mandatory equality sign and the second type.
- let ty = self.parse_ty()?;
- if self.eat(&token::Colon) {
- let bounds = self.parse_generic_bounds(Some(self.prev_span))?;
- where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
- ast::WhereBoundPredicate {
- span: lo.to(self.prev_span),
- bound_generic_params: lifetime_defs,
- bounded_ty: ty,
- bounds,
- }
- ));
- // FIXME: Decide what should be used here, `=` or `==`.
- // FIXME: We are just dropping the binders in lifetime_defs on the floor here.
- } else if self.eat(&token::Eq) || self.eat(&token::EqEq) {
- let rhs_ty = self.parse_ty()?;
- where_clause.predicates.push(ast::WherePredicate::EqPredicate(
- ast::WhereEqPredicate {
- span: lo.to(self.prev_span),
- lhs_ty: ty,
- rhs_ty,
- id: ast::DUMMY_NODE_ID,
- }
- ));
- } else {
- return self.unexpected();
- }
- } else {
- break
- }
-
- if !self.eat(&token::Comma) {
- break
- }
- }
-
- where_clause.span = lo.to(self.prev_span);
- Ok(where_clause)
- }
-
- fn parse_fn_args(&mut self, named_args: bool, allow_c_variadic: bool)
- -> PResult<'a, (Vec<Arg> , bool)> {
- let sp = self.token.span;
- let mut c_variadic = false;
- let (args, _): (Vec<Option<Arg>>, _) = self.parse_paren_comma_seq(|p| {
- let do_not_enforce_named_arguments_for_c_variadic =
- |token: &token::Token| -> bool {
- if token == &token::DotDotDot {
- false
- } else {
- named_args
- }
- };
- match p.parse_arg_general(
- false,
- allow_c_variadic,
- do_not_enforce_named_arguments_for_c_variadic
- ) {
- Ok(arg) => {
- if let TyKind::CVarArgs = arg.ty.node {
- c_variadic = true;
- if p.token != token::CloseDelim(token::Paren) {
- let span = p.token.span;
- p.span_err(span,
- "`...` must be the last argument of a C-variadic function");
- Ok(None)
- } else {
- Ok(Some(arg))
- }
- } else {
- Ok(Some(arg))
- }
- },
- Err(mut e) => {
- e.emit();
- let lo = p.prev_span;
- // Skip every token until next possible arg or end.
- p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]);
- // Create a placeholder argument for proper arg count (issue #34264).
- let span = lo.to(p.prev_span);
- Ok(Some(dummy_arg(Ident::new(kw::Invalid, span))))
- }
- }
- })?;
-
- let args: Vec<_> = args.into_iter().filter_map(|x| x).collect();
-
- if c_variadic && args.is_empty() {
- self.span_err(sp,
- "C-variadic function must be declared with at least one named argument");
- }
-
- Ok((args, c_variadic))
- }
-
- /// Parses the argument list and result type of a function declaration.
- fn parse_fn_decl(&mut self, allow_c_variadic: bool) -> PResult<'a, P<FnDecl>> {
- let (args, c_variadic) = self.parse_fn_args(true, allow_c_variadic)?;
- let ret_ty = self.parse_ret_ty(true)?;
-
- Ok(P(FnDecl {
- inputs: args,
- output: ret_ty,
- c_variadic,
- }))
- }
-
- /// Returns the parsed optional self argument and whether a self shortcut was used.
- ///
- /// See `parse_self_arg_with_attrs` to collect attributes.
- fn parse_self_arg(&mut self) -> PResult<'a, Option<Arg>> {
- let expect_ident = |this: &mut Self| match this.token.kind {
- // Preserve hygienic context.
- token::Ident(name, _) =>
- { let span = this.token.span; this.bump(); Ident::new(name, span) }
- _ => unreachable!()
- };
- let isolated_self = |this: &mut Self, n| {
- this.look_ahead(n, |t| t.is_keyword(kw::SelfLower)) &&
- this.look_ahead(n + 1, |t| t != &token::ModSep)
- };
-
- // Parse optional `self` parameter of a method.
- // Only a limited set of initial token sequences is considered `self` parameters; anything
- // else is parsed as a normal function parameter list, so some lookahead is required.
- let eself_lo = self.token.span;
- let (eself, eself_ident, eself_hi) = match self.token.kind {
- token::BinOp(token::And) => {
- // `&self`
- // `&mut self`
- // `&'lt self`
- // `&'lt mut self`
- // `¬_self`
- (if isolated_self(self, 1) {
- self.bump();
- SelfKind::Region(None, Mutability::Immutable)
- } else if self.is_keyword_ahead(1, &[kw::Mut]) &&
- isolated_self(self, 2) {
- self.bump();
- self.bump();
- SelfKind::Region(None, Mutability::Mutable)
- } else if self.look_ahead(1, |t| t.is_lifetime()) &&
- isolated_self(self, 2) {
- self.bump();
- let lt = self.expect_lifetime();
- SelfKind::Region(Some(lt), Mutability::Immutable)
- } else if self.look_ahead(1, |t| t.is_lifetime()) &&
- self.is_keyword_ahead(2, &[kw::Mut]) &&
- isolated_self(self, 3) {
- self.bump();
- let lt = self.expect_lifetime();
- self.bump();
- SelfKind::Region(Some(lt), Mutability::Mutable)
- } else {
- return Ok(None);
- }, expect_ident(self), self.prev_span)
- }
- token::BinOp(token::Star) => {
- // `*self`
- // `*const self`
- // `*mut self`
- // `*not_self`
- // Emit special error for `self` cases.
- let msg = "cannot pass `self` by raw pointer";
- (if isolated_self(self, 1) {
- self.bump();
- self.struct_span_err(self.token.span, msg)
- .span_label(self.token.span, msg)
- .emit();
- SelfKind::Value(Mutability::Immutable)
- } else if self.look_ahead(1, |t| t.is_mutability()) &&
- isolated_self(self, 2) {
- self.bump();
- self.bump();
- self.struct_span_err(self.token.span, msg)
- .span_label(self.token.span, msg)
- .emit();
- SelfKind::Value(Mutability::Immutable)
- } else {
- return Ok(None);
- }, expect_ident(self), self.prev_span)
- }
- token::Ident(..) => {
- if isolated_self(self, 0) {
- // `self`
- // `self: TYPE`
- let eself_ident = expect_ident(self);
- let eself_hi = self.prev_span;
- (if self.eat(&token::Colon) {
- let ty = self.parse_ty()?;
- SelfKind::Explicit(ty, Mutability::Immutable)
- } else {
- SelfKind::Value(Mutability::Immutable)
- }, eself_ident, eself_hi)
- } else if self.token.is_keyword(kw::Mut) &&
- isolated_self(self, 1) {
- // `mut self`
- // `mut self: TYPE`
- self.bump();
- let eself_ident = expect_ident(self);
- let eself_hi = self.prev_span;
- (if self.eat(&token::Colon) {
- let ty = self.parse_ty()?;
- SelfKind::Explicit(ty, Mutability::Mutable)
- } else {
- SelfKind::Value(Mutability::Mutable)
- }, eself_ident, eself_hi)
- } else {
- return Ok(None);
- }
- }
- _ => return Ok(None),
- };
-
- let eself = source_map::respan(eself_lo.to(eself_hi), eself);
- Ok(Some(Arg::from_self(ThinVec::default(), eself, eself_ident)))
- }
-
- /// Returns the parsed optional self argument with attributes and whether a self
- /// shortcut was used.
- fn parse_self_arg_with_attrs(&mut self) -> PResult<'a, Option<Arg>> {
- let attrs = self.parse_arg_attributes()?;
- let arg_opt = self.parse_self_arg()?;
- Ok(arg_opt.map(|mut arg| {
- arg.attrs = attrs.into();
- arg
- }))
- }
-
- /// Parses the parameter list and result type of a function that may have a `self` parameter.
- fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> PResult<'a, P<FnDecl>>
- where F: FnMut(&mut Parser<'a>) -> PResult<'a, Arg>,
- {
- self.expect(&token::OpenDelim(token::Paren))?;
-
- // Parse optional self argument.
- let self_arg = self.parse_self_arg_with_attrs()?;
-
- // Parse the rest of the function parameter list.
- let sep = SeqSep::trailing_allowed(token::Comma);
- let (mut fn_inputs, recovered) = if let Some(self_arg) = self_arg {
- if self.check(&token::CloseDelim(token::Paren)) {
- (vec![self_arg], false)
- } else if self.eat(&token::Comma) {
- let mut fn_inputs = vec![self_arg];
- let (mut input, _, recovered) = self.parse_seq_to_before_end(
- &token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
- fn_inputs.append(&mut input);
- (fn_inputs, recovered)
- } else {
- match self.expect_one_of(&[], &[]) {
- Err(err) => return Err(err),
- Ok(recovered) => (vec![self_arg], recovered),
- }
- }
- } else {
- let (input, _, recovered) =
- self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
- (input, recovered)
- };
-
- if !recovered {
- // Parse closing paren and return type.
- self.expect(&token::CloseDelim(token::Paren))?;
- }
- // Replace duplicated recovered arguments with `_` pattern to avoid unecessary errors.
- self.deduplicate_recovered_arg_names(&mut fn_inputs);
-
- Ok(P(FnDecl {
- inputs: fn_inputs,
- output: self.parse_ret_ty(true)?,
- c_variadic: false
- }))
- }
-
- /// Parses the `|arg, arg|` header of a closure.
- fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
- let inputs_captures = {
- if self.eat(&token::OrOr) {
- Vec::new()
- } else {
- self.expect(&token::BinOp(token::Or))?;
- let args = self.parse_seq_to_before_tokens(
- &[&token::BinOp(token::Or), &token::OrOr],
- SeqSep::trailing_allowed(token::Comma),
- TokenExpectType::NoExpect,
- |p| p.parse_fn_block_arg()
- )?.0;
- self.expect_or()?;
- args
- }
- };
- let output = self.parse_ret_ty(true)?;
-
- Ok(P(FnDecl {
- inputs: inputs_captures,
- output,
- c_variadic: false
- }))
- }
-
- /// Parses the name and optional generic types of a function header.
- fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
- let id = self.parse_ident()?;
- let generics = self.parse_generics()?;
- Ok((id, generics))
- }
-
- fn mk_item(&self, span: Span, ident: Ident, node: ItemKind, vis: Visibility,
- attrs: Vec<Attribute>) -> P<Item> {
- P(Item {
- ident,
- attrs,
- id: ast::DUMMY_NODE_ID,
- node,
- vis,
- span,
- tokens: None,
- })
- }
-
- /// Parses an item-position function declaration.
- fn parse_item_fn(&mut self,
- unsafety: Unsafety,
- asyncness: Spanned<IsAsync>,
- constness: Spanned<Constness>,
- abi: Abi)
- -> PResult<'a, ItemInfo> {
- let (ident, mut generics) = self.parse_fn_header()?;
- let allow_c_variadic = abi == Abi::C && unsafety == Unsafety::Unsafe;
- let decl = self.parse_fn_decl(allow_c_variadic)?;
- generics.where_clause = self.parse_where_clause()?;
- let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
- let header = FnHeader { unsafety, asyncness, constness, abi };
- Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs)))
- }
-
- /// Returns `true` if we are looking at `const ID`
- /// (returns `false` for things like `const fn`, etc.).
- fn is_const_item(&self) -> bool {
- self.token.is_keyword(kw::Const) &&
- !self.is_keyword_ahead(1, &[kw::Fn, kw::Unsafe])
- }
-
- /// Parses all the "front matter" for a `fn` declaration, up to
- /// and including the `fn` keyword:
- ///
- /// - `const fn`
- /// - `unsafe fn`
- /// - `const unsafe fn`
- /// - `extern fn`
- /// - etc.
- fn parse_fn_front_matter(&mut self)
- -> PResult<'a, (
- Spanned<Constness>,
- Unsafety,
- Spanned<IsAsync>,
- Abi
- )>
- {
- let is_const_fn = self.eat_keyword(kw::Const);
- let const_span = self.prev_span;
- let asyncness = self.parse_asyncness();
- if let IsAsync::Async { .. } = asyncness {
- self.ban_async_in_2015(self.prev_span);
- }
- let asyncness = respan(self.prev_span, asyncness);
- let unsafety = self.parse_unsafety();
- let (constness, unsafety, abi) = if is_const_fn {
- (respan(const_span, Constness::Const), unsafety, Abi::Rust)
- } else {
- let abi = if self.eat_keyword(kw::Extern) {
- self.parse_opt_abi()?.unwrap_or(Abi::C)
- } else {
- Abi::Rust
- };
- (respan(self.prev_span, Constness::NotConst), unsafety, abi)
- };
- if !self.eat_keyword(kw::Fn) {
- // It is possible for `expect_one_of` to recover given the contents of
- // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't
- // account for this.
- if !self.expect_one_of(&[], &[])? { unreachable!() }
- }
- Ok((constness, unsafety, asyncness, abi))
- }
-
- /// Parses an impl item.
- pub fn parse_impl_item(&mut self, at_end: &mut bool) -> PResult<'a, ImplItem> {
- maybe_whole!(self, NtImplItem, |x| x);
- let attrs = self.parse_outer_attributes()?;
- let mut unclosed_delims = vec![];
- let (mut item, tokens) = self.collect_tokens(|this| {
- let item = this.parse_impl_item_(at_end, attrs);
- unclosed_delims.append(&mut this.unclosed_delims);
- item
- })?;
- self.unclosed_delims.append(&mut unclosed_delims);
-
- // See `parse_item` for why this clause is here.
- if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
- item.tokens = Some(tokens);
- }
- Ok(item)
- }
-
- fn parse_impl_item_(&mut self,
- at_end: &mut bool,
- mut attrs: Vec<Attribute>) -> PResult<'a, ImplItem> {
- let lo = self.token.span;
- let vis = self.parse_visibility(false)?;
- let defaultness = self.parse_defaultness();
- let (name, node, generics) = if let Some(type_) = self.eat_type() {
- let (name, alias, generics) = type_?;
- let kind = match alias {
- AliasKind::Weak(typ) => ast::ImplItemKind::TyAlias(typ),
- AliasKind::OpaqueTy(bounds) => ast::ImplItemKind::OpaqueTy(bounds),
- };
- (name, kind, generics)
- } else if self.is_const_item() {
- // This parses the grammar:
- // ImplItemConst = "const" Ident ":" Ty "=" Expr ";"
- self.expect_keyword(kw::Const)?;
- let name = self.parse_ident()?;
- self.expect(&token::Colon)?;
- let typ = self.parse_ty()?;
- self.expect(&token::Eq)?;
- let expr = self.parse_expr()?;
- self.expect(&token::Semi)?;
- (name, ast::ImplItemKind::Const(typ, expr), ast::Generics::default())
- } else {
- let (name, inner_attrs, generics, node) = self.parse_impl_method(&vis, at_end)?;
- attrs.extend(inner_attrs);
- (name, node, generics)
- };
-
- Ok(ImplItem {
- id: ast::DUMMY_NODE_ID,
- span: lo.to(self.prev_span),
- ident: name,
- vis,
- defaultness,
- attrs,
- generics,
- node,
- tokens: None,
- })
- }
-
- fn complain_if_pub_macro(&self, vis: &VisibilityKind, sp: Span) {
- match *vis {
- VisibilityKind::Inherited => {}
- _ => {
- let mut err = if self.token.is_keyword(sym::macro_rules) {
- let mut err = self.diagnostic()
- .struct_span_err(sp, "can't qualify macro_rules invocation with `pub`");
- err.span_suggestion(
- sp,
- "try exporting the macro",
- "#[macro_export]".to_owned(),
- Applicability::MaybeIncorrect // speculative
- );
- err
- } else {
- let mut err = self.diagnostic()
- .struct_span_err(sp, "can't qualify macro invocation with `pub`");
- err.help("try adjusting the macro to put `pub` inside the invocation");
- err
- };
- err.emit();
- }
- }
- }
-
- fn missing_assoc_item_kind_err(&self, item_type: &str, prev_span: Span)
- -> DiagnosticBuilder<'a>
- {
- let expected_kinds = if item_type == "extern" {
- "missing `fn`, `type`, or `static`"
- } else {
- "missing `fn`, `type`, or `const`"
- };
-
- // Given this code `path(`, it seems like this is not
- // setting the visibility of a macro invocation, but rather
- // a mistyped method declaration.
- // Create a diagnostic pointing out that `fn` is missing.
- //
- // x | pub path(&self) {
- // | ^ missing `fn`, `type`, or `const`
- // pub path(
- // ^^ `sp` below will point to this
- let sp = prev_span.between(self.prev_span);
- let mut err = self.diagnostic().struct_span_err(
- sp,
- &format!("{} for {}-item declaration",
- expected_kinds, item_type));
- err.span_label(sp, expected_kinds);
- err
- }
-
- /// Parse a method or a macro invocation in a trait impl.
- fn parse_impl_method(&mut self, vis: &Visibility, at_end: &mut bool)
- -> PResult<'a, (Ident, Vec<Attribute>, ast::Generics,
- ast::ImplItemKind)> {
- // code copied from parse_macro_use_or_failure... abstraction!
- if let Some(mac) = self.parse_assoc_macro_invoc("impl", Some(vis), at_end)? {
- // method macro
- Ok((Ident::invalid(), vec![], ast::Generics::default(),
- ast::ImplItemKind::Macro(mac)))
- } else {
- let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
- let ident = self.parse_ident()?;
- let mut generics = self.parse_generics()?;
- let decl = self.parse_fn_decl_with_self(|p| {
- p.parse_arg_general(true, false, |_| true)
- })?;
- generics.where_clause = self.parse_where_clause()?;
- *at_end = true;
- let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
- let header = ast::FnHeader { abi, unsafety, constness, asyncness };
- Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method(
- ast::MethodSig { header, decl },
- body
- )))
- }
- }
-
- /// Parses `trait Foo { ... }` or `trait Foo = Bar;`.
- fn parse_item_trait(&mut self, is_auto: IsAuto, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
- let ident = self.parse_ident()?;
- let mut tps = self.parse_generics()?;
-
- // Parse optional colon and supertrait bounds.
- let bounds = if self.eat(&token::Colon) {
- self.parse_generic_bounds(Some(self.prev_span))?
- } else {
- Vec::new()
- };
-
- if self.eat(&token::Eq) {
- // it's a trait alias
- let bounds = self.parse_generic_bounds(None)?;
- tps.where_clause = self.parse_where_clause()?;
- self.expect(&token::Semi)?;
- if is_auto == IsAuto::Yes {
- let msg = "trait aliases cannot be `auto`";
- self.struct_span_err(self.prev_span, msg)
- .span_label(self.prev_span, msg)
- .emit();
- }
- if unsafety != Unsafety::Normal {
- let msg = "trait aliases cannot be `unsafe`";
- self.struct_span_err(self.prev_span, msg)
- .span_label(self.prev_span, msg)
- .emit();
- }
- Ok((ident, ItemKind::TraitAlias(tps, bounds), None))
- } else {
- // it's a normal trait
- tps.where_clause = self.parse_where_clause()?;
- self.expect(&token::OpenDelim(token::Brace))?;
- let mut trait_items = vec![];
- while !self.eat(&token::CloseDelim(token::Brace)) {
- if let token::DocComment(_) = self.token.kind {
- if self.look_ahead(1,
- |tok| tok == &token::CloseDelim(token::Brace)) {
- self.diagnostic().struct_span_err_with_code(
- self.token.span,
- "found a documentation comment that doesn't document anything",
- DiagnosticId::Error("E0584".into()),
- )
- .help(
- "doc comments must come before what they document, maybe a \
- comment was intended with `//`?",
- )
- .emit();
- self.bump();
- continue;
- }
- }
- let mut at_end = false;
- match self.parse_trait_item(&mut at_end) {
- Ok(item) => trait_items.push(item),
- Err(mut e) => {
- e.emit();
- if !at_end {
- self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
- }
- }
- }
- }
- Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
- }
- }
-
- fn choose_generics_over_qpath(&self) -> bool {
- // There's an ambiguity between generic parameters and qualified paths in impls.
- // If we see `<` it may start both, so we have to inspect some following tokens.
- // The following combinations can only start generics,
- // but not qualified paths (with one exception):
- // `<` `>` - empty generic parameters
- // `<` `#` - generic parameters with attributes
- // `<` (LIFETIME|IDENT) `>` - single generic parameter
- // `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
- // `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
- // `<` (LIFETIME|IDENT) `=` - generic parameter with a default
- // `<` const - generic const parameter
- // The only truly ambiguous case is
- // `<` IDENT `>` `::` IDENT ...
- // we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
- // because this is what almost always expected in practice, qualified paths in impls
- // (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment.
- self.token == token::Lt &&
- (self.look_ahead(1, |t| t == &token::Pound || t == &token::Gt) ||
- self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) &&
- self.look_ahead(2, |t| t == &token::Gt || t == &token::Comma ||
- t == &token::Colon || t == &token::Eq) ||
- self.is_keyword_ahead(1, &[kw::Const]))
- }
-
- fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> {
- self.expect(&token::OpenDelim(token::Brace))?;
- let attrs = self.parse_inner_attributes()?;
-
- let mut impl_items = Vec::new();
- while !self.eat(&token::CloseDelim(token::Brace)) {
- let mut at_end = false;
- match self.parse_impl_item(&mut at_end) {
- Ok(impl_item) => impl_items.push(impl_item),
- Err(mut err) => {
- err.emit();
- if !at_end {
- self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
- }
- }
- }
- }
- Ok((impl_items, attrs))
- }
-
- /// Parses an implementation item, `impl` keyword is already parsed.
- ///
- /// impl<'a, T> TYPE { /* impl items */ }
- /// impl<'a, T> TRAIT for TYPE { /* impl items */ }
- /// impl<'a, T> !TRAIT for TYPE { /* impl items */ }
- ///
- /// We actually parse slightly more relaxed grammar for better error reporting and recovery.
- /// `impl` GENERICS `!`? TYPE `for`? (TYPE | `..`) (`where` PREDICATES)? `{` BODY `}`
- /// `impl` GENERICS `!`? TYPE (`where` PREDICATES)? `{` BODY `}`
- fn parse_item_impl(&mut self, unsafety: Unsafety, defaultness: Defaultness)
- -> PResult<'a, ItemInfo> {
- // First, parse generic parameters if necessary.
- let mut generics = if self.choose_generics_over_qpath() {
- self.parse_generics()?
- } else {
- ast::Generics::default()
- };
-
- // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
- let polarity = if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
- self.bump(); // `!`
- ast::ImplPolarity::Negative
- } else {
- ast::ImplPolarity::Positive
- };
-
- // Parse both types and traits as a type, then reinterpret if necessary.
- let err_path = |span| ast::Path::from_ident(Ident::new(kw::Invalid, span));
- let ty_first = if self.token.is_keyword(kw::For) &&
- self.look_ahead(1, |t| t != &token::Lt) {
- let span = self.prev_span.between(self.token.span);
- self.struct_span_err(span, "missing trait in a trait impl").emit();
- P(Ty { node: TyKind::Path(None, err_path(span)), span, id: ast::DUMMY_NODE_ID })
- } else {
- self.parse_ty()?
- };
-
- // If `for` is missing we try to recover.
- let has_for = self.eat_keyword(kw::For);
- let missing_for_span = self.prev_span.between(self.token.span);
-
- let ty_second = if self.token == token::DotDot {
- // We need to report this error after `cfg` expansion for compatibility reasons
- self.bump(); // `..`, do not add it to expected tokens
- Some(DummyResult::raw_ty(self.prev_span, true))
- } else if has_for || self.token.can_begin_type() {
- Some(self.parse_ty()?)
- } else {
- None
- };
-
- generics.where_clause = self.parse_where_clause()?;
-
- let (impl_items, attrs) = self.parse_impl_body()?;
-
- let item_kind = match ty_second {
- Some(ty_second) => {
- // impl Trait for Type
- if !has_for {
- self.struct_span_err(missing_for_span, "missing `for` in a trait impl")
- .span_suggestion_short(
- missing_for_span,
- "add `for` here",
- " for ".to_string(),
- Applicability::MachineApplicable,
- ).emit();
- }
-
- let ty_first = ty_first.into_inner();
- let path = match ty_first.node {
- // This notably includes paths passed through `ty` macro fragments (#46438).
- TyKind::Path(None, path) => path,
- _ => {
- self.span_err(ty_first.span, "expected a trait, found type");
- err_path(ty_first.span)
- }
- };
- let trait_ref = TraitRef { path, ref_id: ty_first.id };
-
- ItemKind::Impl(unsafety, polarity, defaultness,
- generics, Some(trait_ref), ty_second, impl_items)
- }
- None => {
- // impl Type
- ItemKind::Impl(unsafety, polarity, defaultness,
- generics, None, ty_first, impl_items)
- }
- };
-
- Ok((Ident::invalid(), item_kind, Some(attrs)))
- }
-
- fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<GenericParam>> {
- if self.eat_keyword(kw::For) {
- self.expect_lt()?;
- let params = self.parse_generic_params()?;
- self.expect_gt()?;
- // We rely on AST validation to rule out invalid cases: There must not be type
- // parameters, and the lifetime parameters must not have bounds.
- Ok(params)
- } else {
- Ok(Vec::new())
- }
- }
-
- /// Parses `struct Foo { ... }`.
- fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
- let class_name = self.parse_ident()?;
-
- let mut generics = self.parse_generics()?;
-
- // There is a special case worth noting here, as reported in issue #17904.
- // If we are parsing a tuple struct it is the case that the where clause
- // should follow the field list. Like so:
- //
- // struct Foo<T>(T) where T: Copy;
- //
- // If we are parsing a normal record-style struct it is the case
- // that the where clause comes before the body, and after the generics.
- // So if we look ahead and see a brace or a where-clause we begin
- // parsing a record style struct.
- //
- // Otherwise if we look ahead and see a paren we parse a tuple-style
- // struct.
-
- let vdata = if self.token.is_keyword(kw::Where) {
- generics.where_clause = self.parse_where_clause()?;
- if self.eat(&token::Semi) {
- // If we see a: `struct Foo<T> where T: Copy;` style decl.
- VariantData::Unit(ast::DUMMY_NODE_ID)
- } else {
- // If we see: `struct Foo<T> where T: Copy { ... }`
- let (fields, recovered) = self.parse_record_struct_body()?;
- VariantData::Struct(fields, recovered)
- }
- // No `where` so: `struct Foo<T>;`
- } else if self.eat(&token::Semi) {
- VariantData::Unit(ast::DUMMY_NODE_ID)
- // Record-style struct definition
- } else if self.token == token::OpenDelim(token::Brace) {
- let (fields, recovered) = self.parse_record_struct_body()?;
- VariantData::Struct(fields, recovered)
- // Tuple-style struct definition with optional where-clause.
- } else if self.token == token::OpenDelim(token::Paren) {
- let body = VariantData::Tuple(self.parse_tuple_struct_body()?, ast::DUMMY_NODE_ID);
- generics.where_clause = self.parse_where_clause()?;
- self.expect(&token::Semi)?;
- body
- } else {
- let token_str = self.this_token_descr();
- let mut err = self.fatal(&format!(
- "expected `where`, `{{`, `(`, or `;` after struct name, found {}",
- token_str
- ));
- err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name");
- return Err(err);
- };
-
- Ok((class_name, ItemKind::Struct(vdata, generics), None))
- }
-
- /// Parses `union Foo { ... }`.
- fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> {
- let class_name = self.parse_ident()?;
-
- let mut generics = self.parse_generics()?;
-
- let vdata = if self.token.is_keyword(kw::Where) {
- generics.where_clause = self.parse_where_clause()?;
- let (fields, recovered) = self.parse_record_struct_body()?;
- VariantData::Struct(fields, recovered)
- } else if self.token == token::OpenDelim(token::Brace) {
- let (fields, recovered) = self.parse_record_struct_body()?;
- VariantData::Struct(fields, recovered)
- } else {
- let token_str = self.this_token_descr();
- let mut err = self.fatal(&format!(
- "expected `where` or `{{` after union name, found {}", token_str));
- err.span_label(self.token.span, "expected `where` or `{` after union name");
- return Err(err);
- };
-
- Ok((class_name, ItemKind::Union(vdata, generics), None))
- }
-
- fn parse_record_struct_body(
- &mut self,
- ) -> PResult<'a, (Vec<StructField>, /* recovered */ bool)> {
- let mut fields = Vec::new();
- let mut recovered = false;
- if self.eat(&token::OpenDelim(token::Brace)) {
- while self.token != token::CloseDelim(token::Brace) {
- let field = self.parse_struct_decl_field().map_err(|e| {
- self.recover_stmt();
- recovered = true;
- e
- });
- match field {
- Ok(field) => fields.push(field),
- Err(mut err) => {
- err.emit();
- }
- }
- }
- self.eat(&token::CloseDelim(token::Brace));
- } else {
- let token_str = self.this_token_descr();
- let mut err = self.fatal(&format!(
- "expected `where`, or `{{` after struct name, found {}", token_str));
- err.span_label(self.token.span, "expected `where`, or `{` after struct name");
- return Err(err);
- }
-
- Ok((fields, recovered))
- }
-
- fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
- // This is the case where we find `struct Foo<T>(T) where T: Copy;`
- // Unit like structs are handled in parse_item_struct function
- self.parse_paren_comma_seq(|p| {
- let attrs = p.parse_outer_attributes()?;
- let lo = p.token.span;
- let vis = p.parse_visibility(true)?;
- let ty = p.parse_ty()?;
- Ok(StructField {
- span: lo.to(ty.span),
- vis,
- ident: None,
- id: ast::DUMMY_NODE_ID,
- ty,
- attrs,
- })
- }).map(|(r, _)| r)
- }
-
- /// Parses a structure field declaration.
- fn parse_single_struct_field(&mut self,
- lo: Span,
- vis: Visibility,
- attrs: Vec<Attribute> )
- -> PResult<'a, StructField> {
- let mut seen_comma: bool = false;
- let a_var = self.parse_name_and_ty(lo, vis, attrs)?;
- if self.token == token::Comma {
- seen_comma = true;
- }
- match self.token.kind {
- token::Comma => {
- self.bump();
- }
- token::CloseDelim(token::Brace) => {}
- token::DocComment(_) => {
- let previous_span = self.prev_span;
- let mut err = self.span_fatal_err(self.token.span, Error::UselessDocComment);
- self.bump(); // consume the doc comment
- let comma_after_doc_seen = self.eat(&token::Comma);
- // `seen_comma` is always false, because we are inside doc block
- // condition is here to make code more readable
- if seen_comma == false && comma_after_doc_seen == true {
- seen_comma = true;
- }
- if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) {
- err.emit();
- } else {
- if seen_comma == false {
- let sp = self.sess.source_map().next_point(previous_span);
- err.span_suggestion(
- sp,
- "missing comma here",
- ",".into(),
- Applicability::MachineApplicable
- );
- }
- return Err(err);
- }
- }
- _ => {
- let sp = self.sess.source_map().next_point(self.prev_span);
- let mut err = self.struct_span_err(sp, &format!("expected `,`, or `}}`, found {}",
- self.this_token_descr()));
- if self.token.is_ident() {
- // This is likely another field; emit the diagnostic and keep going
- err.span_suggestion(
- sp,
- "try adding a comma",
- ",".into(),
- Applicability::MachineApplicable,
- );
- err.emit();
- } else {
- return Err(err)
- }
- }
- }
- Ok(a_var)
- }
-
- /// Parses an element of a struct declaration.
- fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
- let attrs = self.parse_outer_attributes()?;
- let lo = self.token.span;
- let vis = self.parse_visibility(false)?;
- self.parse_single_struct_field(lo, vis, attrs)
- }
-
- /// Parses `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
- /// `pub(self)` for `pub(in self)` and `pub(super)` for `pub(in super)`.
- /// If the following element can't be a tuple (i.e., it's a function definition), then
- /// it's not a tuple struct field), and the contents within the parentheses isn't valid,
- /// so emit a proper diagnostic.
- pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> {
- maybe_whole!(self, NtVis, |x| x);
+ /// Parses `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
+ /// `pub(self)` for `pub(in self)` and `pub(super)` for `pub(in super)`.
+ /// If the following element can't be a tuple (i.e., it's a function definition), then
+ /// it's not a tuple struct field), and the contents within the parentheses isn't valid,
+ /// so emit a proper diagnostic.
+ pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> {
+ maybe_whole!(self, NtVis, |x| x);
self.expected_tokens.push(TokenType::Keyword(kw::Crate));
if self.is_crate_vis() {
return Ok(respan(self.prev_span, VisibilityKind::Crate(CrateSugar::JustCrate)));
}
- if !self.eat_keyword(kw::Pub) {
- // We need a span for our `Spanned<VisibilityKind>`, but there's inherently no
- // keyword to grab a span from for inherited visibility; an empty span at the
- // beginning of the current token would seem to be the "Schelling span".
- return Ok(respan(self.token.span.shrink_to_lo(), VisibilityKind::Inherited))
- }
- let lo = self.prev_span;
-
- if self.check(&token::OpenDelim(token::Paren)) {
- // We don't `self.bump()` the `(` yet because this might be a struct definition where
- // `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`.
- // Because of this, we only `bump` the `(` if we're assured it is appropriate to do so
- // by the following tokens.
- if self.is_keyword_ahead(1, &[kw::Crate]) &&
- self.look_ahead(2, |t| t != &token::ModSep) // account for `pub(crate::foo)`
- {
- // `pub(crate)`
- self.bump(); // `(`
- self.bump(); // `crate`
- self.expect(&token::CloseDelim(token::Paren))?; // `)`
- let vis = respan(
- lo.to(self.prev_span),
- VisibilityKind::Crate(CrateSugar::PubCrate),
- );
- return Ok(vis)
- } else if self.is_keyword_ahead(1, &[kw::In]) {
- // `pub(in path)`
- self.bump(); // `(`
- self.bump(); // `in`
- let path = self.parse_path(PathStyle::Mod)?; // `path`
- self.expect(&token::CloseDelim(token::Paren))?; // `)`
- let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
- path: P(path),
- id: ast::DUMMY_NODE_ID,
- });
- return Ok(vis)
- } else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren)) &&
- self.is_keyword_ahead(1, &[kw::Super, kw::SelfLower])
- {
- // `pub(self)` or `pub(super)`
- self.bump(); // `(`
- let path = self.parse_path(PathStyle::Mod)?; // `super`/`self`
- self.expect(&token::CloseDelim(token::Paren))?; // `)`
- let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
- path: P(path),
- id: ast::DUMMY_NODE_ID,
- });
- return Ok(vis)
- } else if !can_take_tuple { // Provide this diagnostic if this is not a tuple struct
- // `pub(something) fn ...` or `struct X { pub(something) y: Z }`
- self.bump(); // `(`
- let msg = "incorrect visibility restriction";
- let suggestion = r##"some possible visibility restrictions are:
-`pub(crate)`: visible only on the current crate
-`pub(super)`: visible only in the current module's parent
-`pub(in path::to::module)`: visible only on the specified path"##;
- let path = self.parse_path(PathStyle::Mod)?;
- let sp = path.span;
- let help_msg = format!("make this visible only to module `{}` with `in`", path);
- self.expect(&token::CloseDelim(token::Paren))?; // `)`
- struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg)
- .help(suggestion)
- .span_suggestion(
- sp,
- &help_msg,
- format!("in {}", path),
- Applicability::MachineApplicable,
- )
- .emit(); // emit diagnostic, but continue with public visibility
- }
- }
-
- Ok(respan(lo, VisibilityKind::Public))
- }
-
- /// Parses defaultness (i.e., `default` or nothing).
- fn parse_defaultness(&mut self) -> Defaultness {
- // `pub` is included for better error messages
- if self.check_keyword(kw::Default) &&
- self.is_keyword_ahead(1, &[
- kw::Impl,
- kw::Const,
- kw::Fn,
- kw::Unsafe,
- kw::Extern,
- kw::Type,
- kw::Pub,
- ])
- {
- self.bump(); // `default`
- Defaultness::Default
- } else {
- Defaultness::Final
- }
- }
-
- /// Given a termination token, parses all of the items in a module.
- fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> {
- let mut items = vec![];
- while let Some(item) = self.parse_item()? {
- items.push(item);
- self.maybe_consume_incorrect_semicolon(&items);
- }
-
- if !self.eat(term) {
- let token_str = self.this_token_descr();
- if !self.maybe_consume_incorrect_semicolon(&items) {
- let mut err = self.fatal(&format!("expected item, found {}", token_str));
- err.span_label(self.token.span, "expected item");
- return Err(err);
- }
- }
-
- let hi = if self.token.span.is_dummy() {
- inner_lo
- } else {
- self.prev_span
- };
-
- Ok(ast::Mod {
- inner: inner_lo.to(hi),
- items,
- inline: true
- })
- }
-
- fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> {
- let id = if m.is_none() { self.parse_ident_or_underscore() } else { self.parse_ident() }?;
- self.expect(&token::Colon)?;
- let ty = self.parse_ty()?;
- self.expect(&token::Eq)?;
- let e = self.parse_expr()?;
- self.expect(&token::Semi)?;
- let item = match m {
- Some(m) => ItemKind::Static(ty, m, e),
- None => ItemKind::Const(ty, e),
- };
- Ok((id, item, None))
- }
-
- /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
- fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
- let (in_cfg, outer_attrs) = {
- let mut strip_unconfigured = crate::config::StripUnconfigured {
- sess: self.sess,
- features: None, // don't perform gated feature checking
- };
- let mut outer_attrs = outer_attrs.to_owned();
- strip_unconfigured.process_cfg_attrs(&mut outer_attrs);
- (!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs)
- };
-
- let id_span = self.token.span;
- let id = self.parse_ident()?;
- if self.eat(&token::Semi) {
- if in_cfg && self.recurse_into_file_modules {
- // This mod is in an external file. Let's go get it!
- let ModulePathSuccess { path, directory_ownership, warn } =
- self.submod_path(id, &outer_attrs, id_span)?;
- let (module, mut attrs) =
- self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
- // Record that we fetched the mod from an external file
- if warn {
- let attr = attr::mk_attr_outer(
- attr::mk_word_item(Ident::with_empty_ctxt(sym::warn_directory_ownership)));
- attr::mark_known(&attr);
- attrs.push(attr);
- }
- Ok((id, ItemKind::Mod(module), Some(attrs)))
- } else {
- let placeholder = ast::Mod {
- inner: DUMMY_SP,
- items: Vec::new(),
- inline: false
- };
- Ok((id, ItemKind::Mod(placeholder), None))
- }
- } else {
- let old_directory = self.directory.clone();
- self.push_directory(id, &outer_attrs);
-
- self.expect(&token::OpenDelim(token::Brace))?;
- let mod_inner_lo = self.token.span;
- let attrs = self.parse_inner_attributes()?;
- let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
-
- self.directory = old_directory;
- Ok((id, ItemKind::Mod(module), Some(attrs)))
- }
- }
-
- fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
- if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
- self.directory.path.to_mut().push(&path.as_str());
- self.directory.ownership = DirectoryOwnership::Owned { relative: None };
- } else {
- // We have to push on the current module name in the case of relative
- // paths in order to ensure that any additional module paths from inline
- // `mod x { ... }` come after the relative extension.
- //
- // For example, a `mod z { ... }` inside `x/y.rs` should set the current
- // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
- if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
- if let Some(ident) = relative.take() { // remove the relative offset
- self.directory.path.to_mut().push(ident.as_str());
- }
- }
- self.directory.path.to_mut().push(&id.as_str());
- }
- }
-
- pub fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
- if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
- let s = s.as_str();
-
- // On windows, the base path might have the form
- // `\\?\foo\bar` in which case it does not tolerate
- // mixed `/` and `\` separators, so canonicalize
- // `/` to `\`.
- #[cfg(windows)]
- let s = s.replace("/", "\\");
- Some(dir_path.join(s))
- } else {
- None
- }
- }
-
- /// Returns a path to a module.
- pub fn default_submod_path(
- id: ast::Ident,
- relative: Option<ast::Ident>,
- dir_path: &Path,
- source_map: &SourceMap) -> ModulePath
- {
- // If we're in a foo.rs file instead of a mod.rs file,
- // we need to look for submodules in
- // `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
- // `./<id>.rs` and `./<id>/mod.rs`.
- let relative_prefix_string;
- let relative_prefix = if let Some(ident) = relative {
- relative_prefix_string = format!("{}{}", ident.as_str(), path::MAIN_SEPARATOR);
- &relative_prefix_string
- } else {
- ""
- };
-
- let mod_name = id.to_string();
- let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
- let secondary_path_str = format!("{}{}{}mod.rs",
- relative_prefix, mod_name, path::MAIN_SEPARATOR);
- let default_path = dir_path.join(&default_path_str);
- let secondary_path = dir_path.join(&secondary_path_str);
- let default_exists = source_map.file_exists(&default_path);
- let secondary_exists = source_map.file_exists(&secondary_path);
-
- let result = match (default_exists, secondary_exists) {
- (true, false) => Ok(ModulePathSuccess {
- path: default_path,
- directory_ownership: DirectoryOwnership::Owned {
- relative: Some(id),
- },
- warn: false,
- }),
- (false, true) => Ok(ModulePathSuccess {
- path: secondary_path,
- directory_ownership: DirectoryOwnership::Owned {
- relative: None,
- },
- warn: false,
- }),
- (false, false) => Err(Error::FileNotFoundForModule {
- mod_name: mod_name.clone(),
- default_path: default_path_str,
- secondary_path: secondary_path_str,
- dir_path: dir_path.display().to_string(),
- }),
- (true, true) => Err(Error::DuplicatePaths {
- mod_name: mod_name.clone(),
- default_path: default_path_str,
- secondary_path: secondary_path_str,
- }),
- };
-
- ModulePath {
- name: mod_name,
- path_exists: default_exists || secondary_exists,
- result,
- }
- }
-
- fn submod_path(&mut self,
- id: ast::Ident,
- outer_attrs: &[Attribute],
- id_sp: Span)
- -> PResult<'a, ModulePathSuccess> {
- if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
- return Ok(ModulePathSuccess {
- directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
- // All `#[path]` files are treated as though they are a `mod.rs` file.
- // This means that `mod foo;` declarations inside `#[path]`-included
- // files are siblings,
- //
- // Note that this will produce weirdness when a file named `foo.rs` is
- // `#[path]` included and contains a `mod foo;` declaration.
- // If you encounter this, it's your own darn fault :P
- Some(_) => DirectoryOwnership::Owned { relative: None },
- _ => DirectoryOwnership::UnownedViaMod(true),
- },
- path,
- warn: false,
- });
- }
-
- let relative = match self.directory.ownership {
- DirectoryOwnership::Owned { relative } => relative,
- DirectoryOwnership::UnownedViaBlock |
- DirectoryOwnership::UnownedViaMod(_) => None,
- };
- let paths = Parser::default_submod_path(
- id, relative, &self.directory.path, self.sess.source_map());
-
- match self.directory.ownership {
- DirectoryOwnership::Owned { .. } => {
- paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
- },
- DirectoryOwnership::UnownedViaBlock => {
- let msg =
- "Cannot declare a non-inline module inside a block \
- unless it has a path attribute";
- let mut err = self.diagnostic().struct_span_err(id_sp, msg);
- if paths.path_exists {
- let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
- paths.name);
- err.span_note(id_sp, &msg);
- }
- Err(err)
- }
- DirectoryOwnership::UnownedViaMod(warn) => {
- if warn {
- if let Ok(result) = paths.result {
- return Ok(ModulePathSuccess { warn: true, ..result });
- }
- }
- let mut err = self.diagnostic().struct_span_err(id_sp,
- "cannot declare a new module at this location");
- if !id_sp.is_dummy() {
- let src_path = self.sess.source_map().span_to_filename(id_sp);
- if let FileName::Real(src_path) = src_path {
- if let Some(stem) = src_path.file_stem() {
- let mut dest_path = src_path.clone();
- dest_path.set_file_name(stem);
- dest_path.push("mod.rs");
- err.span_note(id_sp,
- &format!("maybe move this module `{}` to its own \
- directory via `{}`", src_path.display(),
- dest_path.display()));
- }
- }
- }
- if paths.path_exists {
- err.span_note(id_sp,
- &format!("... or maybe `use` the module `{}` instead \
- of possibly redeclaring it",
- paths.name));
- }
- Err(err)
- }
- }
- }
-
- /// Reads a module from a source file.
- fn eval_src_mod(
- &mut self,
- path: PathBuf,
- directory_ownership: DirectoryOwnership,
- name: String,
- id_sp: Span,
- ) -> PResult<'a, (ast::Mod, Vec<Attribute>)> {
- let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
- if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
- let mut err = String::from("circular modules: ");
- let len = included_mod_stack.len();
- for p in &included_mod_stack[i.. len] {
- err.push_str(&p.to_string_lossy());
- err.push_str(" -> ");
- }
- err.push_str(&path.to_string_lossy());
- return Err(self.span_fatal(id_sp, &err[..]));
- }
- included_mod_stack.push(path.clone());
- drop(included_mod_stack);
-
- let mut p0 =
- new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
- p0.cfg_mods = self.cfg_mods;
- let mod_inner_lo = p0.token.span;
- let mod_attrs = p0.parse_inner_attributes()?;
- let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
- m0.inline = false;
- self.sess.included_mod_stack.borrow_mut().pop();
- Ok((m0, mod_attrs))
- }
-
- /// Parses a function declaration from a foreign module.
- fn parse_item_foreign_fn(
- &mut self,
- vis: ast::Visibility,
- lo: Span,
- attrs: Vec<Attribute>,
- extern_sp: Span,
- ) -> PResult<'a, ForeignItem> {
- self.expect_keyword(kw::Fn)?;
-
- let (ident, mut generics) = self.parse_fn_header()?;
- let decl = self.parse_fn_decl(true)?;
- generics.where_clause = self.parse_where_clause()?;
- let hi = self.token.span;
- self.parse_semi_or_incorrect_foreign_fn_body(&ident, extern_sp)?;
- Ok(ast::ForeignItem {
- ident,
- attrs,
- node: ForeignItemKind::Fn(decl, generics),
- id: ast::DUMMY_NODE_ID,
- span: lo.to(hi),
- vis,
- })
- }
-
- /// Parses a static item from a foreign module.
- /// Assumes that the `static` keyword is already parsed.
- fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
- -> PResult<'a, ForeignItem> {
- let mutbl = self.parse_mutability();
- let ident = self.parse_ident()?;
- self.expect(&token::Colon)?;
- let ty = self.parse_ty()?;
- let hi = self.token.span;
- self.expect(&token::Semi)?;
- Ok(ForeignItem {
- ident,
- attrs,
- node: ForeignItemKind::Static(ty, mutbl),
- id: ast::DUMMY_NODE_ID,
- span: lo.to(hi),
- vis,
- })
- }
-
- /// Parses a type from a foreign module.
- fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
- -> PResult<'a, ForeignItem> {
- self.expect_keyword(kw::Type)?;
-
- let ident = self.parse_ident()?;
- let hi = self.token.span;
- self.expect(&token::Semi)?;
- Ok(ast::ForeignItem {
- ident,
- attrs,
- node: ForeignItemKind::Ty,
- id: ast::DUMMY_NODE_ID,
- span: lo.to(hi),
- vis
- })
- }
-
- fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, ast::Ident> {
- let error_msg = "crate name using dashes are not valid in `extern crate` statements";
- let suggestion_msg = "if the original crate name uses dashes you need to use underscores \
- in the code";
- let mut ident = if self.token.is_keyword(kw::SelfLower) {
- self.parse_path_segment_ident()
- } else {
- self.parse_ident()
- }?;
- let mut idents = vec![];
- let mut replacement = vec![];
- let mut fixed_crate_name = false;
- // Accept `extern crate name-like-this` for better diagnostics
- let dash = token::BinOp(token::BinOpToken::Minus);
- if self.token == dash { // Do not include `-` as part of the expected tokens list
- while self.eat(&dash) {
- fixed_crate_name = true;
- replacement.push((self.prev_span, "_".to_string()));
- idents.push(self.parse_ident()?);
- }
- }
- if fixed_crate_name {
- let fixed_name_sp = ident.span.to(idents.last().unwrap().span);
- let mut fixed_name = format!("{}", ident.name);
- for part in idents {
- fixed_name.push_str(&format!("_{}", part.name));
- }
- ident = Ident::from_str(&fixed_name).with_span_pos(fixed_name_sp);
-
- self.struct_span_err(fixed_name_sp, error_msg)
- .span_label(fixed_name_sp, "dash-separated idents are not valid")
- .multipart_suggestion(suggestion_msg, replacement, Applicability::MachineApplicable)
- .emit();
- }
- Ok(ident)
- }
-
- /// Parses `extern crate` links.
- ///
- /// # Examples
- ///
- /// ```
- /// extern crate foo;
- /// extern crate bar as foo;
- /// ```
- fn parse_item_extern_crate(&mut self,
- lo: Span,
- visibility: Visibility,
- attrs: Vec<Attribute>)
- -> PResult<'a, P<Item>> {
- // Accept `extern crate name-like-this` for better diagnostics
- let orig_name = self.parse_crate_name_with_dashes()?;
- let (item_name, orig_name) = if let Some(rename) = self.parse_rename()? {
- (rename, Some(orig_name.name))
- } else {
- (orig_name, None)
- };
- self.expect(&token::Semi)?;
-
- let span = lo.to(self.prev_span);
- Ok(self.mk_item(span, item_name, ItemKind::ExternCrate(orig_name), visibility, attrs))
- }
-
- /// Parses `extern` for foreign ABIs modules.
- ///
- /// `extern` is expected to have been
- /// consumed before calling this method.
- ///
- /// # Examples
- ///
- /// ```ignore (only-for-syntax-highlight)
- /// extern "C" {}
- /// extern {}
- /// ```
- fn parse_item_foreign_mod(
- &mut self,
- lo: Span,
- opt_abi: Option<Abi>,
- visibility: Visibility,
- mut attrs: Vec<Attribute>,
- extern_sp: Span,
- ) -> PResult<'a, P<Item>> {
- self.expect(&token::OpenDelim(token::Brace))?;
-
- let abi = opt_abi.unwrap_or(Abi::C);
-
- attrs.extend(self.parse_inner_attributes()?);
-
- let mut foreign_items = vec![];
- while !self.eat(&token::CloseDelim(token::Brace)) {
- foreign_items.push(self.parse_foreign_item(extern_sp)?);
- }
-
- let prev_span = self.prev_span;
- let m = ast::ForeignMod {
- abi,
- items: foreign_items
- };
- let invalid = Ident::invalid();
- Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs))
- }
-
- /// Parses `type Foo = Bar;` or returns `None`
- /// without modifying the parser state.
- fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> {
- // This parses the grammar:
- // Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";"
- if self.eat_keyword(kw::Type) {
- Some(self.parse_type_alias())
- } else {
- None
+ if !self.eat_keyword(kw::Pub) {
+ // We need a span for our `Spanned<VisibilityKind>`, but there's inherently no
+ // keyword to grab a span from for inherited visibility; an empty span at the
+ // beginning of the current token would seem to be the "Schelling span".
+ return Ok(respan(self.token.span.shrink_to_lo(), VisibilityKind::Inherited))
}
- }
-
- /// Parses a type alias or opaque type.
- fn parse_type_alias(&mut self) -> PResult<'a, (Ident, AliasKind, ast::Generics)> {
- let ident = self.parse_ident()?;
- let mut tps = self.parse_generics()?;
- tps.where_clause = self.parse_where_clause()?;
- self.expect(&token::Eq)?;
- let alias = if self.check_keyword(kw::Impl) {
- self.bump();
- let bounds = self.parse_generic_bounds(Some(self.prev_span))?;
- AliasKind::OpaqueTy(bounds)
- } else {
- let ty = self.parse_ty()?;
- AliasKind::Weak(ty)
- };
- self.expect(&token::Semi)?;
- Ok((ident, alias, tps))
- }
-
- /// Parses the part of an enum declaration following the `{`.
- fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
- let mut variants = Vec::new();
- while self.token != token::CloseDelim(token::Brace) {
- let variant_attrs = self.parse_outer_attributes()?;
- let vlo = self.token.span;
-
- self.eat_bad_pub();
- let ident = self.parse_ident()?;
-
- let struct_def = if self.check(&token::OpenDelim(token::Brace)) {
- // Parse a struct variant.
- let (fields, recovered) = self.parse_record_struct_body()?;
- VariantData::Struct(fields, recovered)
- } else if self.check(&token::OpenDelim(token::Paren)) {
- VariantData::Tuple(
- self.parse_tuple_struct_body()?,
- ast::DUMMY_NODE_ID,
- )
- } else {
- VariantData::Unit(ast::DUMMY_NODE_ID)
- };
+ let lo = self.prev_span;
- let disr_expr = if self.eat(&token::Eq) {
- Some(AnonConst {
+ if self.check(&token::OpenDelim(token::Paren)) {
+ // We don't `self.bump()` the `(` yet because this might be a struct definition where
+ // `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`.
+ // Because of this, we only `bump` the `(` if we're assured it is appropriate to do so
+ // by the following tokens.
+ if self.is_keyword_ahead(1, &[kw::Crate]) &&
+ self.look_ahead(2, |t| t != &token::ModSep) // account for `pub(crate::foo)`
+ {
+ // `pub(crate)`
+ self.bump(); // `(`
+ self.bump(); // `crate`
+ self.expect(&token::CloseDelim(token::Paren))?; // `)`
+ let vis = respan(
+ lo.to(self.prev_span),
+ VisibilityKind::Crate(CrateSugar::PubCrate),
+ );
+ return Ok(vis)
+ } else if self.is_keyword_ahead(1, &[kw::In]) {
+ // `pub(in path)`
+ self.bump(); // `(`
+ self.bump(); // `in`
+ let path = self.parse_path(PathStyle::Mod)?; // `path`
+ self.expect(&token::CloseDelim(token::Paren))?; // `)`
+ let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
+ path: P(path),
id: ast::DUMMY_NODE_ID,
- value: self.parse_expr()?,
- })
- } else {
- None
- };
-
- let vr = ast::Variant_ {
- ident,
- id: ast::DUMMY_NODE_ID,
- attrs: variant_attrs,
- data: struct_def,
- disr_expr,
- };
- variants.push(respan(vlo.to(self.prev_span), vr));
-
- if !self.eat(&token::Comma) {
- if self.token.is_ident() && !self.token.is_reserved_ident() {
- let sp = self.sess.source_map().next_point(self.prev_span);
- self.struct_span_err(sp, "missing comma")
- .span_suggestion_short(
- sp,
- "missing comma",
- ",".to_owned(),
- Applicability::MaybeIncorrect,
- )
- .emit();
- } else {
- break;
- }
+ });
+ return Ok(vis)
+ } else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren)) &&
+ self.is_keyword_ahead(1, &[kw::Super, kw::SelfLower])
+ {
+ // `pub(self)` or `pub(super)`
+ self.bump(); // `(`
+ let path = self.parse_path(PathStyle::Mod)?; // `super`/`self`
+ self.expect(&token::CloseDelim(token::Paren))?; // `)`
+ let vis = respan(lo.to(self.prev_span), VisibilityKind::Restricted {
+ path: P(path),
+ id: ast::DUMMY_NODE_ID,
+ });
+ return Ok(vis)
+ } else if !can_take_tuple { // Provide this diagnostic if this is not a tuple struct
+ // `pub(something) fn ...` or `struct X { pub(something) y: Z }`
+ self.bump(); // `(`
+ let msg = "incorrect visibility restriction";
+ let suggestion = r##"some possible visibility restrictions are:
+`pub(crate)`: visible only on the current crate
+`pub(super)`: visible only in the current module's parent
+`pub(in path::to::module)`: visible only on the specified path"##;
+ let path = self.parse_path(PathStyle::Mod)?;
+ let sp = path.span;
+ let help_msg = format!("make this visible only to module `{}` with `in`", path);
+ self.expect(&token::CloseDelim(token::Paren))?; // `)`
+ struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg)
+ .help(suggestion)
+ .span_suggestion(
+ sp,
+ &help_msg,
+ format!("in {}", path),
+ Applicability::MachineApplicable,
+ )
+ .emit(); // emit diagnostic, but continue with public visibility
}
}
- self.expect(&token::CloseDelim(token::Brace))?;
-
- Ok(ast::EnumDef { variants })
- }
- /// Parses an enum declaration.
- fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
- let id = self.parse_ident()?;
- let mut generics = self.parse_generics()?;
- generics.where_clause = self.parse_where_clause()?;
- self.expect(&token::OpenDelim(token::Brace))?;
-
- let enum_definition = self.parse_enum_def(&generics).map_err(|e| {
- self.recover_stmt();
- self.eat(&token::CloseDelim(token::Brace));
- e
- })?;
- Ok((id, ItemKind::Enum(enum_definition, generics), None))
+ Ok(respan(lo, VisibilityKind::Public))
}
/// Parses a string as an ABI spec on an extern type or module. Consumes
}
}
- fn is_static_global(&mut self) -> bool {
- if self.check_keyword(kw::Static) {
- // Check if this could be a closure
- !self.look_ahead(1, |token| {
- if token.is_keyword(kw::Move) {
- return true;
- }
- match token.kind {
- token::BinOp(token::Or) | token::OrOr => true,
- _ => false,
- }
- })
- } else {
- false
- }
- }
-
- fn parse_item_(
- &mut self,
- attrs: Vec<Attribute>,
- macros_allowed: bool,
- attributes_allowed: bool,
- ) -> PResult<'a, Option<P<Item>>> {
- let mut unclosed_delims = vec![];
- let (ret, tokens) = self.collect_tokens(|this| {
- let item = this.parse_item_implementation(attrs, macros_allowed, attributes_allowed);
- unclosed_delims.append(&mut this.unclosed_delims);
- item
- })?;
- self.unclosed_delims.append(&mut unclosed_delims);
-
- // Once we've parsed an item and recorded the tokens we got while
- // parsing we may want to store `tokens` into the item we're about to
- // return. Note, though, that we specifically didn't capture tokens
- // related to outer attributes. The `tokens` field here may later be
- // used with procedural macros to convert this item back into a token
- // stream, but during expansion we may be removing attributes as we go
- // along.
- //
- // If we've got inner attributes then the `tokens` we've got above holds
- // these inner attributes. If an inner attribute is expanded we won't
- // actually remove it from the token stream, so we'll just keep yielding
- // it (bad!). To work around this case for now we just avoid recording
- // `tokens` if we detect any inner attributes. This should help keep
- // expansion correct, but we should fix this bug one day!
- Ok(ret.map(|item| {
- item.map(|mut i| {
- if !i.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
- i.tokens = Some(tokens);
- }
- i
- })
- }))
- }
-
- /// Parses one of the items allowed by the flags.
- fn parse_item_implementation(
- &mut self,
- attrs: Vec<Attribute>,
- macros_allowed: bool,
- attributes_allowed: bool,
- ) -> PResult<'a, Option<P<Item>>> {
- maybe_whole!(self, NtItem, |item| {
- let mut item = item.into_inner();
- let mut attrs = attrs;
- mem::swap(&mut item.attrs, &mut attrs);
- item.attrs.extend(attrs);
- Some(P(item))
- });
-
- let lo = self.token.span;
-
- let visibility = self.parse_visibility(false)?;
-
- if self.eat_keyword(kw::Use) {
- // USE ITEM
- let item_ = ItemKind::Use(P(self.parse_use_tree()?));
- self.expect(&token::Semi)?;
-
- let span = lo.to(self.prev_span);
- let item =
- self.mk_item(span, Ident::invalid(), item_, visibility, attrs);
- return Ok(Some(item));
- }
-
- if self.eat_keyword(kw::Extern) {
- let extern_sp = self.prev_span;
- if self.eat_keyword(kw::Crate) {
- return Ok(Some(self.parse_item_extern_crate(lo, visibility, attrs)?));
- }
-
- let opt_abi = self.parse_opt_abi()?;
-
- if self.eat_keyword(kw::Fn) {
- // EXTERN FUNCTION ITEM
- let fn_span = self.prev_span;
- let abi = opt_abi.unwrap_or(Abi::C);
- let (ident, item_, extra_attrs) =
- self.parse_item_fn(Unsafety::Normal,
- respan(fn_span, IsAsync::NotAsync),
- respan(fn_span, Constness::NotConst),
- abi)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- } else if self.check(&token::OpenDelim(token::Brace)) {
- return Ok(Some(
- self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs, extern_sp)?,
- ));
- }
-
- self.unexpected()?;
- }
-
- if self.is_static_global() {
- self.bump();
- // STATIC ITEM
- let m = if self.eat_keyword(kw::Mut) {
- Mutability::Mutable
- } else {
- Mutability::Immutable
- };
- let (ident, item_, extra_attrs) = self.parse_item_const(Some(m))?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.eat_keyword(kw::Const) {
- let const_span = self.prev_span;
- if self.check_keyword(kw::Fn)
- || (self.check_keyword(kw::Unsafe)
- && self.is_keyword_ahead(1, &[kw::Fn])) {
- // CONST FUNCTION ITEM
- let unsafety = self.parse_unsafety();
- self.bump();
- let (ident, item_, extra_attrs) =
- self.parse_item_fn(unsafety,
- respan(const_span, IsAsync::NotAsync),
- respan(const_span, Constness::Const),
- Abi::Rust)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
-
- // CONST ITEM
- if self.eat_keyword(kw::Mut) {
- let prev_span = self.prev_span;
- self.struct_span_err(prev_span, "const globals cannot be mutable")
- .span_label(prev_span, "cannot be mutable")
- .span_suggestion(
- const_span,
- "you might want to declare a static instead",
- "static".to_owned(),
- Applicability::MaybeIncorrect,
- )
- .emit();
- }
- let (ident, item_, extra_attrs) = self.parse_item_const(None)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
-
- // Parse `async unsafe? fn`.
- if self.check_keyword(kw::Async) {
- let async_span = self.token.span;
- if self.is_keyword_ahead(1, &[kw::Fn])
- || self.is_keyword_ahead(2, &[kw::Fn])
- {
- // ASYNC FUNCTION ITEM
- self.bump(); // `async`
- let unsafety = self.parse_unsafety(); // `unsafe`?
- self.expect_keyword(kw::Fn)?; // `fn`
- let fn_span = self.prev_span;
- let (ident, item_, extra_attrs) =
- self.parse_item_fn(unsafety,
- respan(async_span, IsAsync::Async {
- closure_id: ast::DUMMY_NODE_ID,
- return_impl_trait_id: ast::DUMMY_NODE_ID,
- }),
- respan(fn_span, Constness::NotConst),
- Abi::Rust)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- self.ban_async_in_2015(async_span);
- return Ok(Some(item));
- }
- }
- if self.check_keyword(kw::Unsafe) &&
- self.is_keyword_ahead(1, &[kw::Trait, kw::Auto])
- {
- // UNSAFE TRAIT ITEM
- self.bump(); // `unsafe`
- let is_auto = if self.eat_keyword(kw::Trait) {
- IsAuto::No
- } else {
- self.expect_keyword(kw::Auto)?;
- self.expect_keyword(kw::Trait)?;
- IsAuto::Yes
- };
- let (ident, item_, extra_attrs) =
- self.parse_item_trait(is_auto, Unsafety::Unsafe)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.check_keyword(kw::Impl) ||
- self.check_keyword(kw::Unsafe) &&
- self.is_keyword_ahead(1, &[kw::Impl]) ||
- self.check_keyword(kw::Default) &&
- self.is_keyword_ahead(1, &[kw::Impl, kw::Unsafe]) {
- // IMPL ITEM
- let defaultness = self.parse_defaultness();
- let unsafety = self.parse_unsafety();
- self.expect_keyword(kw::Impl)?;
- let (ident, item, extra_attrs) = self.parse_item_impl(unsafety, defaultness)?;
- let span = lo.to(self.prev_span);
- return Ok(Some(self.mk_item(span, ident, item, visibility,
- maybe_append(attrs, extra_attrs))));
- }
- if self.check_keyword(kw::Fn) {
- // FUNCTION ITEM
- self.bump();
- let fn_span = self.prev_span;
- let (ident, item_, extra_attrs) =
- self.parse_item_fn(Unsafety::Normal,
- respan(fn_span, IsAsync::NotAsync),
- respan(fn_span, Constness::NotConst),
- Abi::Rust)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.check_keyword(kw::Unsafe)
- && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
- // UNSAFE FUNCTION ITEM
- self.bump(); // `unsafe`
- // `{` is also expected after `unsafe`, in case of error, include it in the diagnostic
- self.check(&token::OpenDelim(token::Brace));
- let abi = if self.eat_keyword(kw::Extern) {
- self.parse_opt_abi()?.unwrap_or(Abi::C)
- } else {
- Abi::Rust
- };
- self.expect_keyword(kw::Fn)?;
- let fn_span = self.prev_span;
- let (ident, item_, extra_attrs) =
- self.parse_item_fn(Unsafety::Unsafe,
- respan(fn_span, IsAsync::NotAsync),
- respan(fn_span, Constness::NotConst),
- abi)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.eat_keyword(kw::Mod) {
- // MODULE ITEM
- let (ident, item_, extra_attrs) =
- self.parse_item_mod(&attrs[..])?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if let Some(type_) = self.eat_type() {
- let (ident, alias, generics) = type_?;
- // TYPE ITEM
- let item_ = match alias {
- AliasKind::Weak(ty) => ItemKind::TyAlias(ty, generics),
- AliasKind::OpaqueTy(bounds) => ItemKind::OpaqueTy(bounds, generics),
- };
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- attrs);
- return Ok(Some(item));
- }
- if self.eat_keyword(kw::Enum) {
- // ENUM ITEM
- let (ident, item_, extra_attrs) = self.parse_item_enum()?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.check_keyword(kw::Trait)
- || (self.check_keyword(kw::Auto)
- && self.is_keyword_ahead(1, &[kw::Trait]))
- {
- let is_auto = if self.eat_keyword(kw::Trait) {
- IsAuto::No
- } else {
- self.expect_keyword(kw::Auto)?;
- self.expect_keyword(kw::Trait)?;
- IsAuto::Yes
- };
- // TRAIT ITEM
- let (ident, item_, extra_attrs) =
- self.parse_item_trait(is_auto, Unsafety::Normal)?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.eat_keyword(kw::Struct) {
- // STRUCT ITEM
- let (ident, item_, extra_attrs) = self.parse_item_struct()?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if self.is_union_item() {
- // UNION ITEM
- self.bump();
- let (ident, item_, extra_attrs) = self.parse_item_union()?;
- let prev_span = self.prev_span;
- let item = self.mk_item(lo.to(prev_span),
- ident,
- item_,
- visibility,
- maybe_append(attrs, extra_attrs));
- return Ok(Some(item));
- }
- if let Some(macro_def) = self.eat_macro_def(&attrs, &visibility, lo)? {
- return Ok(Some(macro_def));
- }
-
- // Verify whether we have encountered a struct or method definition where the user forgot to
- // add the `struct` or `fn` keyword after writing `pub`: `pub S {}`
- if visibility.node.is_pub() &&
- self.check_ident() &&
- self.look_ahead(1, |t| *t != token::Not)
- {
- // Space between `pub` keyword and the identifier
- //
- // pub S {}
- // ^^^ `sp` points here
- let sp = self.prev_span.between(self.token.span);
- let full_sp = self.prev_span.to(self.token.span);
- let ident_sp = self.token.span;
- if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) {
- // possible public struct definition where `struct` was forgotten
- let ident = self.parse_ident().unwrap();
- let msg = format!("add `struct` here to parse `{}` as a public struct",
- ident);
- let mut err = self.diagnostic()
- .struct_span_err(sp, "missing `struct` for struct definition");
- err.span_suggestion_short(
- sp, &msg, " struct ".into(), Applicability::MaybeIncorrect // speculative
- );
- return Err(err);
- } else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) {
- let ident = self.parse_ident().unwrap();
- self.bump(); // `(`
- let kw_name = if let Ok(Some(_)) = self.parse_self_arg_with_attrs()
- .map_err(|mut e| e.cancel())
- {
- "method"
- } else {
- "function"
- };
- self.consume_block(token::Paren);
- let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) {
- self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]);
- self.bump(); // `{`
- ("fn", kw_name, false)
- } else if self.check(&token::OpenDelim(token::Brace)) {
- self.bump(); // `{`
- ("fn", kw_name, false)
- } else if self.check(&token::Colon) {
- let kw = "struct";
- (kw, kw, false)
- } else {
- ("fn` or `struct", "function or struct", true)
- };
-
- let msg = format!("missing `{}` for {} definition", kw, kw_name);
- let mut err = self.diagnostic().struct_span_err(sp, &msg);
- if !ambiguous {
- self.consume_block(token::Brace);
- let suggestion = format!("add `{}` here to parse `{}` as a public {}",
- kw,
- ident,
- kw_name);
- err.span_suggestion_short(
- sp, &suggestion, format!(" {} ", kw), Applicability::MachineApplicable
- );
- } else {
- if let Ok(snippet) = self.span_to_snippet(ident_sp) {
- err.span_suggestion(
- full_sp,
- "if you meant to call a macro, try",
- format!("{}!", snippet),
- // this is the `ambiguous` conditional branch
- Applicability::MaybeIncorrect
- );
- } else {
- err.help("if you meant to call a macro, remove the `pub` \
- and add a trailing `!` after the identifier");
- }
- }
- return Err(err);
- } else if self.look_ahead(1, |t| *t == token::Lt) {
- let ident = self.parse_ident().unwrap();
- self.eat_to_tokens(&[&token::Gt]);
- self.bump(); // `>`
- let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) {
- if let Ok(Some(_)) = self.parse_self_arg_with_attrs()
- .map_err(|mut e| e.cancel())
- {
- ("fn", "method", false)
- } else {
- ("fn", "function", false)
- }
- } else if self.check(&token::OpenDelim(token::Brace)) {
- ("struct", "struct", false)
- } else {
- ("fn` or `struct", "function or struct", true)
- };
- let msg = format!("missing `{}` for {} definition", kw, kw_name);
- let mut err = self.diagnostic().struct_span_err(sp, &msg);
- if !ambiguous {
- err.span_suggestion_short(
- sp,
- &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
- format!(" {} ", kw),
- Applicability::MachineApplicable,
- );
- }
- return Err(err);
- }
- }
- self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility)
- }
-
/// We are parsing `async fn`. If we are on Rust 2015, emit an error.
fn ban_async_in_2015(&self, async_span: Span) {
if async_span.rust_2015() {
}
}
- /// Parses a foreign item.
- crate fn parse_foreign_item(&mut self, extern_sp: Span) -> PResult<'a, ForeignItem> {
- maybe_whole!(self, NtForeignItem, |ni| ni);
-
- let attrs = self.parse_outer_attributes()?;
- let lo = self.token.span;
- let visibility = self.parse_visibility(false)?;
-
- // FOREIGN STATIC ITEM
- // Treat `const` as `static` for error recovery, but don't add it to expected tokens.
- if self.check_keyword(kw::Static) || self.token.is_keyword(kw::Const) {
- if self.token.is_keyword(kw::Const) {
- self.diagnostic()
- .struct_span_err(self.token.span, "extern items cannot be `const`")
- .span_suggestion(
- self.token.span,
- "try using a static value",
- "static".to_owned(),
- Applicability::MachineApplicable
- ).emit();
- }
- self.bump(); // `static` or `const`
- return Ok(self.parse_item_foreign_static(visibility, lo, attrs)?);
- }
- // FOREIGN FUNCTION ITEM
- if self.check_keyword(kw::Fn) {
- return Ok(self.parse_item_foreign_fn(visibility, lo, attrs, extern_sp)?);
- }
- // FOREIGN TYPE ITEM
- if self.check_keyword(kw::Type) {
- return Ok(self.parse_item_foreign_type(visibility, lo, attrs)?);
- }
-
- match self.parse_assoc_macro_invoc("extern", Some(&visibility), &mut false)? {
- Some(mac) => {
- Ok(
- ForeignItem {
- ident: Ident::invalid(),
- span: lo.to(self.prev_span),
- id: ast::DUMMY_NODE_ID,
- attrs,
- vis: visibility,
- node: ForeignItemKind::Macro(mac),
- }
- )
- }
- None => {
- if !attrs.is_empty() {
- self.expected_item_err(&attrs)?;
- }
-
- self.unexpected()
- }
- }
- }
-
- /// This is the fall-through for parsing items.
- fn parse_macro_use_or_failure(
- &mut self,
- attrs: Vec<Attribute> ,
- macros_allowed: bool,
- attributes_allowed: bool,
- lo: Span,
- visibility: Visibility
- ) -> PResult<'a, Option<P<Item>>> {
- if macros_allowed && self.token.is_path_start() &&
- !(self.is_async_fn() && self.token.span.rust_2015()) {
- // MACRO INVOCATION ITEM
-
- let prev_span = self.prev_span;
- self.complain_if_pub_macro(&visibility.node, prev_span);
-
- let mac_lo = self.token.span;
-
- // item macro.
- let path = self.parse_path(PathStyle::Mod)?;
- self.expect(&token::Not)?;
- let (delim, tts) = self.expect_delimited_token_tree()?;
- if delim != MacDelimiter::Brace && !self.eat(&token::Semi) {
- self.report_invalid_macro_expansion_item();
- }
-
- let hi = self.prev_span;
- let mac = respan(mac_lo.to(hi), Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- });
- let item =
- self.mk_item(lo.to(hi), Ident::invalid(), ItemKind::Mac(mac), visibility, attrs);
- return Ok(Some(item));
- }
-
- // FAILURE TO PARSE ITEM
- match visibility.node {
- VisibilityKind::Inherited => {}
- _ => {
- return Err(self.span_fatal(self.prev_span, "unmatched visibility `pub`"));
- }
- }
-
- if !attributes_allowed && !attrs.is_empty() {
- self.expected_item_err(&attrs)?;
- }
- Ok(None)
- }
-
- /// Parses a macro invocation inside a `trait`, `impl` or `extern` block.
- fn parse_assoc_macro_invoc(&mut self, item_kind: &str, vis: Option<&Visibility>,
- at_end: &mut bool) -> PResult<'a, Option<Mac>>
- {
- if self.token.is_path_start() &&
- !(self.is_async_fn() && self.token.span.rust_2015()) {
- let prev_span = self.prev_span;
- let lo = self.token.span;
- let path = self.parse_path(PathStyle::Mod)?;
-
- if path.segments.len() == 1 {
- if !self.eat(&token::Not) {
- return Err(self.missing_assoc_item_kind_err(item_kind, prev_span));
- }
- } else {
- self.expect(&token::Not)?;
- }
-
- if let Some(vis) = vis {
- self.complain_if_pub_macro(&vis.node, prev_span);
- }
-
- *at_end = true;
-
- // eat a matched-delimiter token tree:
- let (delim, tts) = self.expect_delimited_token_tree()?;
- if delim != MacDelimiter::Brace {
- self.expect(&token::Semi)?;
- }
-
- Ok(Some(respan(lo.to(self.prev_span), Mac_ {
- path,
- tts,
- delim,
- prior_type_ascription: self.last_type_ascription,
- })))
- } else {
- Ok(None)
- }
- }
-
fn collect_tokens<F, R>(&mut self, f: F) -> PResult<'a, (R, TokenStream)>
where F: FnOnce(&mut Self) -> PResult<'a, R>
{
Ok((ret?, TokenStream::new(collected_tokens)))
}
- pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
- let attrs = self.parse_outer_attributes()?;
- self.parse_item_(attrs, true, false)
- }
-
/// `::{` or `::*`
fn is_import_coupler(&mut self) -> bool {
self.check(&token::ModSep) &&
*t == token::BinOp(token::Star))
}
- /// Parses a `UseTree`.
- ///
- /// ```
- /// USE_TREE = [`::`] `*` |
- /// [`::`] `{` USE_TREE_LIST `}` |
- /// PATH `::` `*` |
- /// PATH `::` `{` USE_TREE_LIST `}` |
- /// PATH [`as` IDENT]
- /// ```
- fn parse_use_tree(&mut self) -> PResult<'a, UseTree> {
- let lo = self.token.span;
-
- let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo() };
- let kind = if self.check(&token::OpenDelim(token::Brace)) ||
- self.check(&token::BinOp(token::Star)) ||
- self.is_import_coupler() {
- // `use *;` or `use ::*;` or `use {...};` or `use ::{...};`
- let mod_sep_ctxt = self.token.span.ctxt();
- if self.eat(&token::ModSep) {
- prefix.segments.push(
- PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt))
- );
- }
-
- if self.eat(&token::BinOp(token::Star)) {
- UseTreeKind::Glob
- } else {
- UseTreeKind::Nested(self.parse_use_tree_list()?)
- }
- } else {
- // `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;`
- prefix = self.parse_path(PathStyle::Mod)?;
-
- if self.eat(&token::ModSep) {
- if self.eat(&token::BinOp(token::Star)) {
- UseTreeKind::Glob
- } else {
- UseTreeKind::Nested(self.parse_use_tree_list()?)
- }
- } else {
- UseTreeKind::Simple(self.parse_rename()?, ast::DUMMY_NODE_ID, ast::DUMMY_NODE_ID)
- }
- };
-
- Ok(UseTree { prefix, kind, span: lo.to(self.prev_span) })
- }
-
- /// Parses a `UseTreeKind::Nested(list)`.
- ///
- /// ```
- /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
- /// ```
- fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
- self.parse_delim_comma_seq(token::Brace, |p| Ok((p.parse_use_tree()?, ast::DUMMY_NODE_ID)))
- .map(|(r, _)| r)
- }
-
- fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
- if self.eat_keyword(kw::As) {
- self.parse_ident_or_underscore().map(Some)
- } else {
- Ok(None)
- }
- }
-
- /// Parses a source module as a crate. This is the main entry point for the parser.
- pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
- let lo = self.token.span;
- let krate = Ok(ast::Crate {
- attrs: self.parse_inner_attributes()?,
- module: self.parse_mod_items(&token::Eof, lo)?,
- span: lo.to(self.token.span),
- });
- krate
- }
-
pub fn parse_optional_str(&mut self) -> Option<(Symbol, ast::StrStyle, Option<ast::Name>)> {
let ret = match self.token.kind {
token::Literal(token::Lit { kind: token::Str, symbol, suffix }) =>
--- /dev/null
+use super::{Parser, PResult, Restrictions, PrevTokenKind, TokenType, PathStyle};
+use super::{BlockMode, SemiColonMode};
+use super::{SeqSep, TokenExpectType};
+
+use crate::maybe_recover_from_interpolated_ty_qpath;
+use crate::ptr::P;
+use crate::ast::{self, Attribute, AttrStyle, Ident, CaptureBy, BlockCheckMode};
+use crate::ast::{Expr, ExprKind, RangeLimits, Label, Movability, IsAsync, Arm};
+use crate::ast::{Ty, TyKind, FunctionRetTy, Arg, FnDecl};
+use crate::ast::{BinOpKind, BinOp, UnOp};
+use crate::ast::{Mac_, AnonConst, Field};
+
+use crate::parse::classify;
+use crate::parse::token::{self, Token};
+use crate::parse::diagnostics::{Error};
+use crate::print::pprust;
+use crate::source_map::{self, respan, Span};
+use crate::symbol::{kw, sym};
+use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par};
+
+use std::mem;
+use errors::Applicability;
+use rustc_data_structures::thin_vec::ThinVec;
+
+/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
+/// dropped into the token stream, which happens while parsing the result of
+/// macro expansion). Placement of these is not as complex as I feared it would
+/// be. The important thing is to make sure that lookahead doesn't balk at
+/// `token::Interpolated` tokens.
+macro_rules! maybe_whole_expr {
+ ($p:expr) => {
+ if let token::Interpolated(nt) = &$p.token.kind {
+ match &**nt {
+ token::NtExpr(e) | token::NtLiteral(e) => {
+ let e = e.clone();
+ $p.bump();
+ return Ok(e);
+ }
+ token::NtPath(path) => {
+ let path = path.clone();
+ $p.bump();
+ return Ok($p.mk_expr(
+ $p.token.span, ExprKind::Path(None, path), ThinVec::new()
+ ));
+ }
+ token::NtBlock(block) => {
+ let block = block.clone();
+ $p.bump();
+ return Ok($p.mk_expr(
+ $p.token.span, ExprKind::Block(block, None), ThinVec::new()
+ ));
+ }
+ // N.B: `NtIdent(ident)` is normalized to `Ident` in `fn bump`.
+ _ => {},
+ };
+ }
+ }
+}
+
+#[derive(Debug)]
+pub(super) enum LhsExpr {
+ NotYetParsed,
+ AttributesParsed(ThinVec<Attribute>),
+ AlreadyParsed(P<Expr>),
+}
+
+impl From<Option<ThinVec<Attribute>>> for LhsExpr {
+ fn from(o: Option<ThinVec<Attribute>>) -> Self {
+ if let Some(attrs) = o {
+ LhsExpr::AttributesParsed(attrs)
+ } else {
+ LhsExpr::NotYetParsed
+ }
+ }
+}
+
+impl From<P<Expr>> for LhsExpr {
+ fn from(expr: P<Expr>) -> Self {
+ LhsExpr::AlreadyParsed(expr)
+ }
+}
+
+impl<'a> Parser<'a> {
+ /// Parses an expression.
+ #[inline]
+ pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
+ self.parse_expr_res(Restrictions::empty(), None)
+ }
+
+ fn parse_paren_expr_seq(&mut self) -> PResult<'a, Vec<P<Expr>>> {
+ self.parse_paren_comma_seq(|p| {
+ match p.parse_expr() {
+ Ok(expr) => Ok(expr),
+ Err(mut err) => match p.token.kind {
+ token::Ident(name, false)
+ if name == kw::Underscore && p.look_ahead(1, |t| {
+ t == &token::Comma
+ }) => {
+ // Special-case handling of `foo(_, _, _)`
+ err.emit();
+ let sp = p.token.span;
+ p.bump();
+ Ok(p.mk_expr(sp, ExprKind::Err, ThinVec::new()))
+ }
+ _ => Err(err),
+ },
+ }
+ }).map(|(r, _)| r)
+ }
+
+ /// Parses an expression, subject to the given restrictions.
+ #[inline]
+ pub(super) fn parse_expr_res(
+ &mut self,
+ r: Restrictions,
+ already_parsed_attrs: Option<ThinVec<Attribute>>
+ ) -> PResult<'a, P<Expr>> {
+ self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
+ }
+
+ /// Parses an associative expression.
+ ///
+ /// This parses an expression accounting for associativity and precedence of the operators in
+ /// the expression.
+ #[inline]
+ fn parse_assoc_expr(
+ &mut self,
+ already_parsed_attrs: Option<ThinVec<Attribute>>,
+ ) -> PResult<'a, P<Expr>> {
+ self.parse_assoc_expr_with(0, already_parsed_attrs.into())
+ }
+
+ /// Parses an associative expression with operators of at least `min_prec` precedence.
+ pub(super) fn parse_assoc_expr_with(
+ &mut self,
+ min_prec: usize,
+ lhs: LhsExpr,
+ ) -> PResult<'a, P<Expr>> {
+ let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
+ expr
+ } else {
+ let attrs = match lhs {
+ LhsExpr::AttributesParsed(attrs) => Some(attrs),
+ _ => None,
+ };
+ if [token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind) {
+ return self.parse_prefix_range_expr(attrs);
+ } else {
+ self.parse_prefix_expr(attrs)?
+ }
+ };
+ let last_type_ascription_set = self.last_type_ascription.is_some();
+
+ match (self.expr_is_complete(&lhs), AssocOp::from_token(&self.token)) {
+ (true, None) => {
+ self.last_type_ascription = None;
+ // Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071
+ return Ok(lhs);
+ }
+ (false, _) => {} // continue parsing the expression
+ // An exhaustive check is done in the following block, but these are checked first
+ // because they *are* ambiguous but also reasonable looking incorrect syntax, so we
+ // want to keep their span info to improve diagnostics in these cases in a later stage.
+ (true, Some(AssocOp::Multiply)) | // `{ 42 } *foo = bar;` or `{ 42 } * 3`
+ (true, Some(AssocOp::Subtract)) | // `{ 42 } -5`
+ (true, Some(AssocOp::LAnd)) | // `{ 42 } &&x` (#61475)
+ (true, Some(AssocOp::Add)) // `{ 42 } + 42
+ // If the next token is a keyword, then the tokens above *are* unambiguously incorrect:
+ // `if x { a } else { b } && if y { c } else { d }`
+ if !self.look_ahead(1, |t| t.is_reserved_ident()) => {
+ self.last_type_ascription = None;
+ // These cases are ambiguous and can't be identified in the parser alone
+ let sp = self.sess.source_map().start_point(self.token.span);
+ self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
+ return Ok(lhs);
+ }
+ (true, Some(ref op)) if !op.can_continue_expr_unambiguously() => {
+ self.last_type_ascription = None;
+ return Ok(lhs);
+ }
+ (true, Some(_)) => {
+ // We've found an expression that would be parsed as a statement, but the next
+ // token implies this should be parsed as an expression.
+ // For example: `if let Some(x) = x { x } else { 0 } / 2`
+ let mut err = self.struct_span_err(self.token.span, &format!(
+ "expected expression, found `{}`",
+ pprust::token_to_string(&self.token),
+ ));
+ err.span_label(self.token.span, "expected expression");
+ self.sess.expr_parentheses_needed(
+ &mut err,
+ lhs.span,
+ Some(pprust::expr_to_string(&lhs),
+ ));
+ err.emit();
+ }
+ }
+ self.expected_tokens.push(TokenType::Operator);
+ while let Some(op) = AssocOp::from_token(&self.token) {
+
+ // Adjust the span for interpolated LHS to point to the `$lhs` token and not to what
+ // it refers to. Interpolated identifiers are unwrapped early and never show up here
+ // as `PrevTokenKind::Interpolated` so if LHS is a single identifier we always process
+ // it as "interpolated", it doesn't change the answer for non-interpolated idents.
+ let lhs_span = match (self.prev_token_kind, &lhs.node) {
+ (PrevTokenKind::Interpolated, _) => self.prev_span,
+ (PrevTokenKind::Ident, &ExprKind::Path(None, ref path))
+ if path.segments.len() == 1 => self.prev_span,
+ _ => lhs.span,
+ };
+
+ let cur_op_span = self.token.span;
+ let restrictions = if op.is_assign_like() {
+ self.restrictions & Restrictions::NO_STRUCT_LITERAL
+ } else {
+ self.restrictions
+ };
+ let prec = op.precedence();
+ if prec < min_prec {
+ break;
+ }
+ // Check for deprecated `...` syntax
+ if self.token == token::DotDotDot && op == AssocOp::DotDotEq {
+ self.err_dotdotdot_syntax(self.token.span);
+ }
+
+ self.bump();
+ if op.is_comparison() {
+ self.check_no_chained_comparison(&lhs, &op);
+ }
+ // Special cases:
+ if op == AssocOp::As {
+ lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
+ continue
+ } else if op == AssocOp::Colon {
+ let maybe_path = self.could_ascription_be_path(&lhs.node);
+ self.last_type_ascription = Some((self.prev_span, maybe_path));
+
+ lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type)?;
+ continue
+ } else if op == AssocOp::DotDot || op == AssocOp::DotDotEq {
+ // If we didn’t have to handle `x..`/`x..=`, it would be pretty easy to
+ // generalise it to the Fixity::None code.
+ //
+ // We have 2 alternatives here: `x..y`/`x..=y` and `x..`/`x..=` The other
+ // two variants are handled with `parse_prefix_range_expr` call above.
+ let rhs = if self.is_at_start_of_range_notation_rhs() {
+ Some(self.parse_assoc_expr_with(prec + 1, LhsExpr::NotYetParsed)?)
+ } else {
+ None
+ };
+ let (lhs_span, rhs_span) = (lhs.span, if let Some(ref x) = rhs {
+ x.span
+ } else {
+ cur_op_span
+ });
+ let limits = if op == AssocOp::DotDot {
+ RangeLimits::HalfOpen
+ } else {
+ RangeLimits::Closed
+ };
+
+ let r = self.mk_range(Some(lhs), rhs, limits)?;
+ lhs = self.mk_expr(lhs_span.to(rhs_span), r, ThinVec::new());
+ break
+ }
+
+ let fixity = op.fixity();
+ let prec_adjustment = match fixity {
+ Fixity::Right => 0,
+ Fixity::Left => 1,
+ // We currently have no non-associative operators that are not handled above by
+ // the special cases. The code is here only for future convenience.
+ Fixity::None => 1,
+ };
+ let rhs = self.with_res(
+ restrictions - Restrictions::STMT_EXPR,
+ |this| this.parse_assoc_expr_with(prec + prec_adjustment, LhsExpr::NotYetParsed)
+ )?;
+
+ // Make sure that the span of the parent node is larger than the span of lhs and rhs,
+ // including the attributes.
+ let lhs_span = lhs
+ .attrs
+ .iter()
+ .filter(|a| a.style == AttrStyle::Outer)
+ .next()
+ .map_or(lhs_span, |a| a.span);
+ let span = lhs_span.to(rhs.span);
+ lhs = match op {
+ AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
+ AssocOp::Modulus | AssocOp::LAnd | AssocOp::LOr | AssocOp::BitXor |
+ AssocOp::BitAnd | AssocOp::BitOr | AssocOp::ShiftLeft | AssocOp::ShiftRight |
+ AssocOp::Equal | AssocOp::Less | AssocOp::LessEqual | AssocOp::NotEqual |
+ AssocOp::Greater | AssocOp::GreaterEqual => {
+ let ast_op = op.to_ast_binop().unwrap();
+ let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
+ self.mk_expr(span, binary, ThinVec::new())
+ }
+ AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()),
+ AssocOp::AssignOp(k) => {
+ let aop = match k {
+ token::Plus => BinOpKind::Add,
+ token::Minus => BinOpKind::Sub,
+ token::Star => BinOpKind::Mul,
+ token::Slash => BinOpKind::Div,
+ token::Percent => BinOpKind::Rem,
+ token::Caret => BinOpKind::BitXor,
+ token::And => BinOpKind::BitAnd,
+ token::Or => BinOpKind::BitOr,
+ token::Shl => BinOpKind::Shl,
+ token::Shr => BinOpKind::Shr,
+ };
+ let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
+ self.mk_expr(span, aopexpr, ThinVec::new())
+ }
+ AssocOp::As | AssocOp::Colon | AssocOp::DotDot | AssocOp::DotDotEq => {
+ self.bug("AssocOp should have been handled by special case")
+ }
+ };
+
+ if let Fixity::None = fixity { break }
+ }
+ if last_type_ascription_set {
+ self.last_type_ascription = None;
+ }
+ Ok(lhs)
+ }
+
+ /// Checks if this expression is a successfully parsed statement.
+ fn expr_is_complete(&self, e: &Expr) -> bool {
+ self.restrictions.contains(Restrictions::STMT_EXPR) &&
+ !classify::expr_requires_semi_to_be_stmt(e)
+ }
+
+ fn is_at_start_of_range_notation_rhs(&self) -> bool {
+ if self.token.can_begin_expr() {
+ // parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
+ if self.token == token::OpenDelim(token::Brace) {
+ return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
+ }
+ true
+ } else {
+ false
+ }
+ }
+
+ /// Parse prefix-forms of range notation: `..expr`, `..`, `..=expr`
+ fn parse_prefix_range_expr(
+ &mut self,
+ already_parsed_attrs: Option<ThinVec<Attribute>>
+ ) -> PResult<'a, P<Expr>> {
+ // Check for deprecated `...` syntax
+ if self.token == token::DotDotDot {
+ self.err_dotdotdot_syntax(self.token.span);
+ }
+
+ debug_assert!([token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind),
+ "parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
+ self.token);
+ let tok = self.token.clone();
+ let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
+ let lo = self.token.span;
+ let mut hi = self.token.span;
+ self.bump();
+ let opt_end = if self.is_at_start_of_range_notation_rhs() {
+ // RHS must be parsed with more associativity than the dots.
+ let next_prec = AssocOp::from_token(&tok).unwrap().precedence() + 1;
+ Some(self.parse_assoc_expr_with(next_prec, LhsExpr::NotYetParsed)
+ .map(|x| {
+ hi = x.span;
+ x
+ })?)
+ } else {
+ None
+ };
+ let limits = if tok == token::DotDot {
+ RangeLimits::HalfOpen
+ } else {
+ RangeLimits::Closed
+ };
+
+ let r = self.mk_range(None, opt_end, limits)?;
+ Ok(self.mk_expr(lo.to(hi), r, attrs))
+ }
+
+ /// Parse a prefix-unary-operator expr
+ fn parse_prefix_expr(
+ &mut self,
+ already_parsed_attrs: Option<ThinVec<Attribute>>
+ ) -> PResult<'a, P<Expr>> {
+ let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
+ let lo = self.token.span;
+ // Note: when adding new unary operators, don't forget to adjust TokenKind::can_begin_expr()
+ let (hi, ex) = match self.token.kind {
+ token::Not => {
+ self.bump();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), self.mk_unary(UnOp::Not, e))
+ }
+ // Suggest `!` for bitwise negation when encountering a `~`
+ token::Tilde => {
+ self.bump();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ let span_of_tilde = lo;
+ self.struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator")
+ .span_suggestion_short(
+ span_of_tilde,
+ "use `!` to perform bitwise negation",
+ "!".to_owned(),
+ Applicability::MachineApplicable
+ )
+ .emit();
+ (lo.to(span), self.mk_unary(UnOp::Not, e))
+ }
+ token::BinOp(token::Minus) => {
+ self.bump();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), self.mk_unary(UnOp::Neg, e))
+ }
+ token::BinOp(token::Star) => {
+ self.bump();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), self.mk_unary(UnOp::Deref, e))
+ }
+ token::BinOp(token::And) | token::AndAnd => {
+ self.expect_and()?;
+ let m = self.parse_mutability();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), ExprKind::AddrOf(m, e))
+ }
+ token::Ident(..) if self.token.is_keyword(kw::Box) => {
+ self.bump();
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), ExprKind::Box(e))
+ }
+ token::Ident(..) if self.token.is_ident_named(sym::not) => {
+ // `not` is just an ordinary identifier in Rust-the-language,
+ // but as `rustc`-the-compiler, we can issue clever diagnostics
+ // for confused users who really want to say `!`
+ let token_cannot_continue_expr = |t: &Token| match t.kind {
+ // These tokens can start an expression after `!`, but
+ // can't continue an expression after an ident
+ token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw),
+ token::Literal(..) | token::Pound => true,
+ _ => t.is_whole_expr(),
+ };
+ let cannot_continue_expr = self.look_ahead(1, token_cannot_continue_expr);
+ if cannot_continue_expr {
+ self.bump();
+ // Emit the error ...
+ self.struct_span_err(
+ self.token.span,
+ &format!("unexpected {} after identifier",self.this_token_descr())
+ )
+ .span_suggestion_short(
+ // Span the `not` plus trailing whitespace to avoid
+ // trailing whitespace after the `!` in our suggestion
+ self.sess.source_map()
+ .span_until_non_whitespace(lo.to(self.token.span)),
+ "use `!` to perform logical negation",
+ "!".to_owned(),
+ Applicability::MachineApplicable
+ )
+ .emit();
+ // —and recover! (just as if we were in the block
+ // for the `token::Not` arm)
+ let e = self.parse_prefix_expr(None);
+ let (span, e) = self.interpolated_or_expr_span(e)?;
+ (lo.to(span), self.mk_unary(UnOp::Not, e))
+ } else {
+ return self.parse_dot_or_call_expr(Some(attrs));
+ }
+ }
+ _ => { return self.parse_dot_or_call_expr(Some(attrs)); }
+ };
+ return Ok(self.mk_expr(lo.to(hi), ex, attrs));
+ }
+
+ /// Returns the span of expr, if it was not interpolated or the span of the interpolated token.
+ fn interpolated_or_expr_span(
+ &self,
+ expr: PResult<'a, P<Expr>>,
+ ) -> PResult<'a, (Span, P<Expr>)> {
+ expr.map(|e| {
+ if self.prev_token_kind == PrevTokenKind::Interpolated {
+ (self.prev_span, e)
+ } else {
+ (e.span, e)
+ }
+ })
+ }
+
+ fn parse_assoc_op_cast(&mut self, lhs: P<Expr>, lhs_span: Span,
+ expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind)
+ -> PResult<'a, P<Expr>> {
+ let mk_expr = |this: &mut Self, rhs: P<Ty>| {
+ this.mk_expr(lhs_span.to(rhs.span), expr_kind(lhs, rhs), ThinVec::new())
+ };
+
+ // Save the state of the parser before parsing type normally, in case there is a
+ // LessThan comparison after this cast.
+ let parser_snapshot_before_type = self.clone();
+ match self.parse_ty_no_plus() {
+ Ok(rhs) => {
+ Ok(mk_expr(self, rhs))
+ }
+ Err(mut type_err) => {
+ // Rewind to before attempting to parse the type with generics, to recover
+ // from situations like `x as usize < y` in which we first tried to parse
+ // `usize < y` as a type with generic arguments.
+ let parser_snapshot_after_type = self.clone();
+ mem::replace(self, parser_snapshot_before_type);
+
+ match self.parse_path(PathStyle::Expr) {
+ Ok(path) => {
+ let (op_noun, op_verb) = match self.token.kind {
+ token::Lt => ("comparison", "comparing"),
+ token::BinOp(token::Shl) => ("shift", "shifting"),
+ _ => {
+ // We can end up here even without `<` being the next token, for
+ // example because `parse_ty_no_plus` returns `Err` on keywords,
+ // but `parse_path` returns `Ok` on them due to error recovery.
+ // Return original error and parser state.
+ mem::replace(self, parser_snapshot_after_type);
+ return Err(type_err);
+ }
+ };
+
+ // Successfully parsed the type path leaving a `<` yet to parse.
+ type_err.cancel();
+
+ // Report non-fatal diagnostics, keep `x as usize` as an expression
+ // in AST and continue parsing.
+ let msg = format!("`<` is interpreted as a start of generic \
+ arguments for `{}`, not a {}", path, op_noun);
+ let span_after_type = parser_snapshot_after_type.token.span;
+ let expr = mk_expr(self, P(Ty {
+ span: path.span,
+ node: TyKind::Path(None, path),
+ id: ast::DUMMY_NODE_ID
+ }));
+
+ let expr_str = self.span_to_snippet(expr.span)
+ .unwrap_or_else(|_| pprust::expr_to_string(&expr));
+
+ self.struct_span_err(self.token.span, &msg)
+ .span_label(
+ self.look_ahead(1, |t| t.span).to(span_after_type),
+ "interpreted as generic arguments"
+ )
+ .span_label(self.token.span, format!("not interpreted as {}", op_noun))
+ .span_suggestion(
+ expr.span,
+ &format!("try {} the cast value", op_verb),
+ format!("({})", expr_str),
+ Applicability::MachineApplicable
+ )
+ .emit();
+
+ Ok(expr)
+ }
+ Err(mut path_err) => {
+ // Couldn't parse as a path, return original error and parser state.
+ path_err.cancel();
+ mem::replace(self, parser_snapshot_after_type);
+ Err(type_err)
+ }
+ }
+ }
+ }
+ }
+
+ /// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
+ fn parse_dot_or_call_expr(
+ &mut self,
+ already_parsed_attrs: Option<ThinVec<Attribute>>,
+ ) -> PResult<'a, P<Expr>> {
+ let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
+
+ let b = self.parse_bottom_expr();
+ let (span, b) = self.interpolated_or_expr_span(b)?;
+ self.parse_dot_or_call_expr_with(b, span, attrs)
+ }
+
+ pub(super) fn parse_dot_or_call_expr_with(
+ &mut self,
+ e0: P<Expr>,
+ lo: Span,
+ mut attrs: ThinVec<Attribute>,
+ ) -> PResult<'a, P<Expr>> {
+ // Stitch the list of outer attributes onto the return value.
+ // A little bit ugly, but the best way given the current code
+ // structure
+ self.parse_dot_or_call_expr_with_(e0, lo).map(|expr|
+ expr.map(|mut expr| {
+ attrs.extend::<Vec<_>>(expr.attrs.into());
+ expr.attrs = attrs;
+ match expr.node {
+ ExprKind::If(..) if !expr.attrs.is_empty() => {
+ // Just point to the first attribute in there...
+ let span = expr.attrs[0].span;
+ self.span_err(span, "attributes are not yet allowed on `if` expressions");
+ }
+ _ => {}
+ }
+ expr
+ })
+ )
+ }
+
+ fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
+ let mut e = e0;
+ let mut hi;
+ loop {
+ // expr?
+ while self.eat(&token::Question) {
+ let hi = self.prev_span;
+ e = self.mk_expr(lo.to(hi), ExprKind::Try(e), ThinVec::new());
+ }
+
+ // expr.f
+ if self.eat(&token::Dot) {
+ match self.token.kind {
+ token::Ident(..) => {
+ e = self.parse_dot_suffix(e, lo)?;
+ }
+ token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => {
+ let span = self.token.span;
+ self.bump();
+ let field = ExprKind::Field(e, Ident::new(symbol, span));
+ e = self.mk_expr(lo.to(span), field, ThinVec::new());
+
+ self.expect_no_suffix(span, "a tuple index", suffix);
+ }
+ token::Literal(token::Lit { kind: token::Float, symbol, .. }) => {
+ self.bump();
+ let fstr = symbol.as_str();
+ let msg = format!("unexpected token: `{}`", symbol);
+ let mut err = self.diagnostic().struct_span_err(self.prev_span, &msg);
+ err.span_label(self.prev_span, "unexpected token");
+ if fstr.chars().all(|x| "0123456789.".contains(x)) {
+ let float = match fstr.parse::<f64>().ok() {
+ Some(f) => f,
+ None => continue,
+ };
+ let sugg = pprust::to_string(|s| {
+ s.popen();
+ s.print_expr(&e);
+ s.s.word( ".");
+ s.print_usize(float.trunc() as usize);
+ s.pclose();
+ s.s.word(".");
+ s.s.word(fstr.splitn(2, ".").last().unwrap().to_string())
+ });
+ err.span_suggestion(
+ lo.to(self.prev_span),
+ "try parenthesizing the first index",
+ sugg,
+ Applicability::MachineApplicable
+ );
+ }
+ return Err(err);
+
+ }
+ _ => {
+ // FIXME Could factor this out into non_fatal_unexpected or something.
+ let actual = self.this_token_to_string();
+ self.span_err(self.token.span, &format!("unexpected token: `{}`", actual));
+ }
+ }
+ continue;
+ }
+ if self.expr_is_complete(&e) { break; }
+ match self.token.kind {
+ // expr(...)
+ token::OpenDelim(token::Paren) => {
+ let seq = self.parse_paren_expr_seq().map(|es| {
+ let nd = self.mk_call(e, es);
+ let hi = self.prev_span;
+ self.mk_expr(lo.to(hi), nd, ThinVec::new())
+ });
+ e = self.recover_seq_parse_error(token::Paren, lo, seq);
+ }
+
+ // expr[...]
+ // Could be either an index expression or a slicing expression.
+ token::OpenDelim(token::Bracket) => {
+ self.bump();
+ let ix = self.parse_expr()?;
+ hi = self.token.span;
+ self.expect(&token::CloseDelim(token::Bracket))?;
+ let index = self.mk_index(e, ix);
+ e = self.mk_expr(lo.to(hi), index, ThinVec::new())
+ }
+ _ => return Ok(e)
+ }
+ }
+ return Ok(e);
+ }
+
+ /// Assuming we have just parsed `.`, continue parsing into an expression.
+ fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
+ if self.token.span.rust_2018() && self.eat_keyword(kw::Await) {
+ return self.mk_await_expr(self_arg, lo);
+ }
+
+ let segment = self.parse_path_segment(PathStyle::Expr)?;
+ self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren));
+
+ Ok(match self.token.kind {
+ token::OpenDelim(token::Paren) => {
+ // Method call `expr.f()`
+ let mut args = self.parse_paren_expr_seq()?;
+ args.insert(0, self_arg);
+
+ let span = lo.to(self.prev_span);
+ self.mk_expr(span, ExprKind::MethodCall(segment, args), ThinVec::new())
+ }
+ _ => {
+ // Field access `expr.f`
+ if let Some(args) = segment.args {
+ self.span_err(args.span(),
+ "field expressions may not have generic arguments");
+ }
+
+ let span = lo.to(self.prev_span);
+ self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), ThinVec::new())
+ }
+ })
+ }
+
+
+ /// At the bottom (top?) of the precedence hierarchy,
+ /// Parses things like parenthesized exprs, macros, `return`, etc.
+ ///
+ /// N.B., this does not parse outer attributes, and is private because it only works
+ /// correctly if called from `parse_dot_or_call_expr()`.
+ fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
+ maybe_recover_from_interpolated_ty_qpath!(self, true);
+ maybe_whole_expr!(self);
+
+ // Outer attributes are already parsed and will be
+ // added to the return value after the fact.
+ //
+ // Therefore, prevent sub-parser from parsing
+ // attributes by giving them a empty "already parsed" list.
+ let mut attrs = ThinVec::new();
+
+ let lo = self.token.span;
+ let mut hi = self.token.span;
+
+ let ex: ExprKind;
+
+ macro_rules! parse_lit {
+ () => {
+ match self.parse_lit() {
+ Ok(literal) => {
+ hi = self.prev_span;
+ ex = ExprKind::Lit(literal);
+ }
+ Err(mut err) => {
+ self.cancel(&mut err);
+ return Err(self.expected_expression_found());
+ }
+ }
+ }
+ }
+
+ // Note: when adding new syntax here, don't forget to adjust TokenKind::can_begin_expr().
+ match self.token.kind {
+ // This match arm is a special-case of the `_` match arm below and
+ // could be removed without changing functionality, but it's faster
+ // to have it here, especially for programs with large constants.
+ token::Literal(_) => {
+ parse_lit!()
+ }
+ token::OpenDelim(token::Paren) => {
+ self.bump();
+
+ attrs.extend(self.parse_inner_attributes()?);
+
+ // (e) is parenthesized e
+ // (e,) is a tuple with only one field, e
+ let mut es = vec![];
+ let mut trailing_comma = false;
+ let mut recovered = false;
+ while self.token != token::CloseDelim(token::Paren) {
+ es.push(match self.parse_expr() {
+ Ok(es) => es,
+ Err(mut err) => {
+ // recover from parse error in tuple list
+ match self.token.kind {
+ token::Ident(name, false)
+ if name == kw::Underscore && self.look_ahead(1, |t| {
+ t == &token::Comma
+ }) => {
+ // Special-case handling of `Foo<(_, _, _)>`
+ err.emit();
+ let sp = self.token.span;
+ self.bump();
+ self.mk_expr(sp, ExprKind::Err, ThinVec::new())
+ }
+ _ => return Ok(
+ self.recover_seq_parse_error(token::Paren, lo, Err(err)),
+ ),
+ }
+ }
+ });
+ recovered = self.expect_one_of(
+ &[],
+ &[token::Comma, token::CloseDelim(token::Paren)],
+ )?;
+ if self.eat(&token::Comma) {
+ trailing_comma = true;
+ } else {
+ trailing_comma = false;
+ break;
+ }
+ }
+ if !recovered {
+ self.bump();
+ }
+
+ hi = self.prev_span;
+ ex = if es.len() == 1 && !trailing_comma {
+ ExprKind::Paren(es.into_iter().nth(0).unwrap())
+ } else {
+ ExprKind::Tup(es)
+ };
+ }
+ token::OpenDelim(token::Brace) => {
+ return self.parse_block_expr(None, lo, BlockCheckMode::Default, attrs);
+ }
+ token::BinOp(token::Or) | token::OrOr => {
+ return self.parse_lambda_expr(attrs);
+ }
+ token::OpenDelim(token::Bracket) => {
+ self.bump();
+
+ attrs.extend(self.parse_inner_attributes()?);
+
+ if self.eat(&token::CloseDelim(token::Bracket)) {
+ // Empty vector.
+ ex = ExprKind::Array(Vec::new());
+ } else {
+ // Nonempty vector.
+ let first_expr = self.parse_expr()?;
+ if self.eat(&token::Semi) {
+ // Repeating array syntax: [ 0; 512 ]
+ let count = AnonConst {
+ id: ast::DUMMY_NODE_ID,
+ value: self.parse_expr()?,
+ };
+ self.expect(&token::CloseDelim(token::Bracket))?;
+ ex = ExprKind::Repeat(first_expr, count);
+ } else if self.eat(&token::Comma) {
+ // Vector with two or more elements.
+ let remaining_exprs = self.parse_seq_to_end(
+ &token::CloseDelim(token::Bracket),
+ SeqSep::trailing_allowed(token::Comma),
+ |p| Ok(p.parse_expr()?)
+ )?;
+ let mut exprs = vec![first_expr];
+ exprs.extend(remaining_exprs);
+ ex = ExprKind::Array(exprs);
+ } else {
+ // Vector with one element.
+ self.expect(&token::CloseDelim(token::Bracket))?;
+ ex = ExprKind::Array(vec![first_expr]);
+ }
+ }
+ hi = self.prev_span;
+ }
+ _ => {
+ if self.eat_lt() {
+ let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
+ hi = path.span;
+ return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs));
+ }
+ if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) {
+ return self.parse_lambda_expr(attrs);
+ }
+ if self.eat_keyword(kw::If) {
+ return self.parse_if_expr(attrs);
+ }
+ if self.eat_keyword(kw::For) {
+ let lo = self.prev_span;
+ return self.parse_for_expr(None, lo, attrs);
+ }
+ if self.eat_keyword(kw::While) {
+ let lo = self.prev_span;
+ return self.parse_while_expr(None, lo, attrs);
+ }
+ if let Some(label) = self.eat_label() {
+ let lo = label.ident.span;
+ self.expect(&token::Colon)?;
+ if self.eat_keyword(kw::While) {
+ return self.parse_while_expr(Some(label), lo, attrs)
+ }
+ if self.eat_keyword(kw::For) {
+ return self.parse_for_expr(Some(label), lo, attrs)
+ }
+ if self.eat_keyword(kw::Loop) {
+ return self.parse_loop_expr(Some(label), lo, attrs)
+ }
+ if self.token == token::OpenDelim(token::Brace) {
+ return self.parse_block_expr(Some(label),
+ lo,
+ BlockCheckMode::Default,
+ attrs);
+ }
+ let msg = "expected `while`, `for`, `loop` or `{` after a label";
+ let mut err = self.fatal(msg);
+ err.span_label(self.token.span, msg);
+ return Err(err);
+ }
+ if self.eat_keyword(kw::Loop) {
+ let lo = self.prev_span;
+ return self.parse_loop_expr(None, lo, attrs);
+ }
+ if self.eat_keyword(kw::Continue) {
+ let label = self.eat_label();
+ let ex = ExprKind::Continue(label);
+ let hi = self.prev_span;
+ return Ok(self.mk_expr(lo.to(hi), ex, attrs));
+ }
+ if self.eat_keyword(kw::Match) {
+ let match_sp = self.prev_span;
+ return self.parse_match_expr(attrs).map_err(|mut err| {
+ err.span_label(match_sp, "while parsing this match expression");
+ err
+ });
+ }
+ if self.eat_keyword(kw::Unsafe) {
+ return self.parse_block_expr(
+ None,
+ lo,
+ BlockCheckMode::Unsafe(ast::UserProvided),
+ attrs);
+ }
+ if self.is_do_catch_block() {
+ let mut db = self.fatal("found removed `do catch` syntax");
+ db.help("Following RFC #2388, the new non-placeholder syntax is `try`");
+ return Err(db);
+ }
+ if self.is_try_block() {
+ let lo = self.token.span;
+ assert!(self.eat_keyword(kw::Try));
+ return self.parse_try_block(lo, attrs);
+ }
+
+ // Span::rust_2018() is somewhat expensive; don't get it repeatedly.
+ let is_span_rust_2018 = self.token.span.rust_2018();
+ if is_span_rust_2018 && self.check_keyword(kw::Async) {
+ return if self.is_async_block() { // check for `async {` and `async move {`
+ self.parse_async_block(attrs)
+ } else {
+ self.parse_lambda_expr(attrs)
+ };
+ }
+ if self.eat_keyword(kw::Return) {
+ if self.token.can_begin_expr() {
+ let e = self.parse_expr()?;
+ hi = e.span;
+ ex = ExprKind::Ret(Some(e));
+ } else {
+ ex = ExprKind::Ret(None);
+ }
+ } else if self.eat_keyword(kw::Break) {
+ let label = self.eat_label();
+ let e = if self.token.can_begin_expr()
+ && !(self.token == token::OpenDelim(token::Brace)
+ && self.restrictions.contains(
+ Restrictions::NO_STRUCT_LITERAL)) {
+ Some(self.parse_expr()?)
+ } else {
+ None
+ };
+ ex = ExprKind::Break(label, e);
+ hi = self.prev_span;
+ } else if self.eat_keyword(kw::Yield) {
+ if self.token.can_begin_expr() {
+ let e = self.parse_expr()?;
+ hi = e.span;
+ ex = ExprKind::Yield(Some(e));
+ } else {
+ ex = ExprKind::Yield(None);
+ }
+ } else if self.eat_keyword(kw::Let) {
+ return self.parse_let_expr(attrs);
+ } else if is_span_rust_2018 && self.eat_keyword(kw::Await) {
+ let (await_hi, e_kind) = self.parse_incorrect_await_syntax(lo, self.prev_span)?;
+ hi = await_hi;
+ ex = e_kind;
+ } else if self.token.is_path_start() {
+ let path = self.parse_path(PathStyle::Expr)?;
+
+ // `!`, as an operator, is prefix, so we know this isn't that
+ if self.eat(&token::Not) {
+ // MACRO INVOCATION expression
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ hi = self.prev_span;
+ ex = ExprKind::Mac(respan(lo.to(hi), Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ }));
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ if let Some(expr) = self.maybe_parse_struct_expr(lo, &path, &attrs) {
+ return expr;
+ } else {
+ hi = path.span;
+ ex = ExprKind::Path(None, path);
+ }
+ } else {
+ hi = path.span;
+ ex = ExprKind::Path(None, path);
+ }
+ } else {
+ if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
+ // Don't complain about bare semicolons after unclosed braces
+ // recovery in order to keep the error count down. Fixing the
+ // delimiters will possibly also fix the bare semicolon found in
+ // expression context. For example, silence the following error:
+ // ```
+ // error: expected expression, found `;`
+ // --> file.rs:2:13
+ // |
+ // 2 | foo(bar(;
+ // | ^ expected expression
+ // ```
+ self.bump();
+ return Ok(self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()));
+ }
+ parse_lit!()
+ }
+ }
+ }
+
+ let expr = self.mk_expr(lo.to(hi), ex, attrs);
+ self.maybe_recover_from_bad_qpath(expr, true)
+ }
+
+ /// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
+ crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
+ maybe_whole_expr!(self);
+
+ let minus_lo = self.token.span;
+ let minus_present = self.eat(&token::BinOp(token::Minus));
+ let lo = self.token.span;
+ let literal = self.parse_lit()?;
+ let hi = self.prev_span;
+ let expr = self.mk_expr(lo.to(hi), ExprKind::Lit(literal), ThinVec::new());
+
+ if minus_present {
+ let minus_hi = self.prev_span;
+ let unary = self.mk_unary(UnOp::Neg, expr);
+ Ok(self.mk_expr(minus_lo.to(minus_hi), unary, ThinVec::new()))
+ } else {
+ Ok(expr)
+ }
+ }
+
+ /// Parses a block or unsafe block.
+ crate fn parse_block_expr(
+ &mut self,
+ opt_label: Option<Label>,
+ lo: Span,
+ blk_mode: BlockCheckMode,
+ outer_attrs: ThinVec<Attribute>,
+ ) -> PResult<'a, P<Expr>> {
+ self.expect(&token::OpenDelim(token::Brace))?;
+
+ let mut attrs = outer_attrs;
+ attrs.extend(self.parse_inner_attributes()?);
+
+ let blk = self.parse_block_tail(lo, blk_mode)?;
+ return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs));
+ }
+
+ /// Parses `move |args| expr`.
+ fn parse_lambda_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
+ let lo = self.token.span;
+
+ let movability = if self.eat_keyword(kw::Static) {
+ Movability::Static
+ } else {
+ Movability::Movable
+ };
+
+ let asyncness = if self.token.span.rust_2018() {
+ self.parse_asyncness()
+ } else {
+ IsAsync::NotAsync
+ };
+ if asyncness.is_async() {
+ // Feature gate `async ||` closures.
+ self.sess.async_closure_spans.borrow_mut().push(self.prev_span);
+ }
+
+ let capture_clause = self.parse_capture_clause();
+ let decl = self.parse_fn_block_decl()?;
+ let decl_hi = self.prev_span;
+ let body = match decl.output {
+ FunctionRetTy::Default(_) => {
+ let restrictions = self.restrictions - Restrictions::STMT_EXPR;
+ self.parse_expr_res(restrictions, None)?
+ },
+ _ => {
+ // If an explicit return type is given, require a
+ // block to appear (RFC 968).
+ let body_lo = self.token.span;
+ self.parse_block_expr(None, body_lo, BlockCheckMode::Default, ThinVec::new())?
+ }
+ };
+
+ Ok(self.mk_expr(
+ lo.to(body.span),
+ ExprKind::Closure(capture_clause, asyncness, movability, decl, body, lo.to(decl_hi)),
+ attrs))
+ }
+
+ /// Parse an optional `move` prefix to a closure lke construct.
+ fn parse_capture_clause(&mut self) -> CaptureBy {
+ if self.eat_keyword(kw::Move) {
+ CaptureBy::Value
+ } else {
+ CaptureBy::Ref
+ }
+ }
+
+ /// Parses the `|arg, arg|` header of a closure.
+ fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
+ let inputs_captures = {
+ if self.eat(&token::OrOr) {
+ Vec::new()
+ } else {
+ self.expect(&token::BinOp(token::Or))?;
+ let args = self.parse_seq_to_before_tokens(
+ &[&token::BinOp(token::Or), &token::OrOr],
+ SeqSep::trailing_allowed(token::Comma),
+ TokenExpectType::NoExpect,
+ |p| p.parse_fn_block_arg()
+ )?.0;
+ self.expect_or()?;
+ args
+ }
+ };
+ let output = self.parse_ret_ty(true)?;
+
+ Ok(P(FnDecl {
+ inputs: inputs_captures,
+ output,
+ c_variadic: false
+ }))
+ }
+
+ /// Parses an argument in a lambda header (e.g., `|arg, arg|`).
+ fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
+ let lo = self.token.span;
+ let attrs = self.parse_arg_attributes()?;
+ let pat = self.parse_pat(Some("argument name"))?;
+ let t = if self.eat(&token::Colon) {
+ self.parse_ty()?
+ } else {
+ P(Ty {
+ id: ast::DUMMY_NODE_ID,
+ node: TyKind::Infer,
+ span: self.prev_span,
+ })
+ };
+ let span = lo.to(self.token.span);
+ Ok(Arg {
+ attrs: attrs.into(),
+ ty: t,
+ pat,
+ span,
+ id: ast::DUMMY_NODE_ID
+ })
+ }
+
+ /// Parses an `if` expression (`if` token already eaten).
+ fn parse_if_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
+ let lo = self.prev_span;
+ let cond = self.parse_cond_expr()?;
+
+ // Verify that the parsed `if` condition makes sense as a condition. If it is a block, then
+ // verify that the last statement is either an implicit return (no `;`) or an explicit
+ // return. This won't catch blocks with an explicit `return`, but that would be caught by
+ // the dead code lint.
+ if self.eat_keyword(kw::Else) || !cond.returns() {
+ let sp = self.sess.source_map().next_point(lo);
+ let mut err = self.diagnostic()
+ .struct_span_err(sp, "missing condition for `if` statemement");
+ err.span_label(sp, "expected if condition here");
+ return Err(err)
+ }
+ let not_block = self.token != token::OpenDelim(token::Brace);
+ let thn = self.parse_block().map_err(|mut err| {
+ if not_block {
+ err.span_label(lo, "this `if` statement has a condition, but no block");
+ }
+ err
+ })?;
+ let mut els: Option<P<Expr>> = None;
+ let mut hi = thn.span;
+ if self.eat_keyword(kw::Else) {
+ let elexpr = self.parse_else_expr()?;
+ hi = elexpr.span;
+ els = Some(elexpr);
+ }
+ Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs))
+ }
+
+ /// Parse the condition of a `if`- or `while`-expression
+ fn parse_cond_expr(&mut self) -> PResult<'a, P<Expr>> {
+ let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
+
+ if let ExprKind::Let(..) = cond.node {
+ // Remove the last feature gating of a `let` expression since it's stable.
+ let last = self.sess.let_chains_spans.borrow_mut().pop();
+ debug_assert_eq!(cond.span, last.unwrap());
+ }
+
+ Ok(cond)
+ }
+
+ /// Parses a `let $pats = $expr` pseudo-expression.
+ /// The `let` token has already been eaten.
+ fn parse_let_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
+ let lo = self.prev_span;
+ let pats = self.parse_pats()?;
+ self.expect(&token::Eq)?;
+ let expr = self.with_res(
+ Restrictions::NO_STRUCT_LITERAL,
+ |this| this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into())
+ )?;
+ let span = lo.to(expr.span);
+ self.sess.let_chains_spans.borrow_mut().push(span);
+ Ok(self.mk_expr(span, ExprKind::Let(pats, expr), attrs))
+ }
+
+ /// `else` token already eaten
+ fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
+ if self.eat_keyword(kw::If) {
+ return self.parse_if_expr(ThinVec::new());
+ } else {
+ let blk = self.parse_block()?;
+ return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), ThinVec::new()));
+ }
+ }
+
+ /// Parse a 'for' .. 'in' expression ('for' token already eaten)
+ fn parse_for_expr(
+ &mut self,
+ opt_label: Option<Label>,
+ span_lo: Span,
+ mut attrs: ThinVec<Attribute>
+ ) -> PResult<'a, P<Expr>> {
+ // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
+
+ // Record whether we are about to parse `for (`.
+ // This is used below for recovery in case of `for ( $stuff ) $block`
+ // in which case we will suggest `for $stuff $block`.
+ let begin_paren = match self.token.kind {
+ token::OpenDelim(token::Paren) => Some(self.token.span),
+ _ => None,
+ };
+
+ let pat = self.parse_top_level_pat()?;
+ if !self.eat_keyword(kw::In) {
+ let in_span = self.prev_span.between(self.token.span);
+ self.struct_span_err(in_span, "missing `in` in `for` loop")
+ .span_suggestion_short(
+ in_span,
+ "try adding `in` here", " in ".into(),
+ // has been misleading, at least in the past (closed Issue #48492)
+ Applicability::MaybeIncorrect
+ )
+ .emit();
+ }
+ let in_span = self.prev_span;
+ self.check_for_for_in_in_typo(in_span);
+ let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
+
+ let pat = self.recover_parens_around_for_head(pat, &expr, begin_paren);
+
+ let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(iattrs);
+
+ let hi = self.prev_span;
+ Ok(self.mk_expr(span_lo.to(hi), ExprKind::ForLoop(pat, expr, loop_block, opt_label), attrs))
+ }
+
+ /// Parses a `while` or `while let` expression (`while` token already eaten).
+ fn parse_while_expr(
+ &mut self,
+ opt_label: Option<Label>,
+ span_lo: Span,
+ mut attrs: ThinVec<Attribute>
+ ) -> PResult<'a, P<Expr>> {
+ let cond = self.parse_cond_expr()?;
+ let (iattrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(iattrs);
+ let span = span_lo.to(body.span);
+ Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs))
+ }
+
+ /// Parse `loop {...}`, `loop` token already eaten.
+ fn parse_loop_expr(
+ &mut self,
+ opt_label: Option<Label>,
+ span_lo: Span,
+ mut attrs: ThinVec<Attribute>
+ ) -> PResult<'a, P<Expr>> {
+ let (iattrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(iattrs);
+ let span = span_lo.to(body.span);
+ Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs))
+ }
+
+ fn eat_label(&mut self) -> Option<Label> {
+ if let Some(ident) = self.token.lifetime() {
+ let span = self.token.span;
+ self.bump();
+ Some(Label { ident: Ident::new(ident.name, span) })
+ } else {
+ None
+ }
+ }
+
+ // `match` token already eaten
+ fn parse_match_expr(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
+ let match_span = self.prev_span;
+ let lo = self.prev_span;
+ let discriminant = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
+ if let Err(mut e) = self.expect(&token::OpenDelim(token::Brace)) {
+ if self.token == token::Semi {
+ e.span_suggestion_short(
+ match_span,
+ "try removing this `match`",
+ String::new(),
+ Applicability::MaybeIncorrect // speculative
+ );
+ }
+ return Err(e)
+ }
+ attrs.extend(self.parse_inner_attributes()?);
+
+ let mut arms: Vec<Arm> = Vec::new();
+ while self.token != token::CloseDelim(token::Brace) {
+ match self.parse_arm() {
+ Ok(arm) => arms.push(arm),
+ Err(mut e) => {
+ // Recover by skipping to the end of the block.
+ e.emit();
+ self.recover_stmt();
+ let span = lo.to(self.token.span);
+ if self.token == token::CloseDelim(token::Brace) {
+ self.bump();
+ }
+ return Ok(self.mk_expr(span, ExprKind::Match(discriminant, arms), attrs));
+ }
+ }
+ }
+ let hi = self.token.span;
+ self.bump();
+ return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs));
+ }
+
+ crate fn parse_arm(&mut self) -> PResult<'a, Arm> {
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+ let pats = self.parse_pats()?;
+ let guard = if self.eat_keyword(kw::If) {
+ Some(self.parse_expr()?)
+ } else {
+ None
+ };
+ let arrow_span = self.token.span;
+ self.expect(&token::FatArrow)?;
+ let arm_start_span = self.token.span;
+
+ let expr = self.parse_expr_res(Restrictions::STMT_EXPR, None)
+ .map_err(|mut err| {
+ err.span_label(arrow_span, "while parsing the `match` arm starting here");
+ err
+ })?;
+
+ let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
+ && self.token != token::CloseDelim(token::Brace);
+
+ let hi = self.token.span;
+
+ if require_comma {
+ let cm = self.sess.source_map();
+ self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)])
+ .map_err(|mut err| {
+ match (cm.span_to_lines(expr.span), cm.span_to_lines(arm_start_span)) {
+ (Ok(ref expr_lines), Ok(ref arm_start_lines))
+ if arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col
+ && expr_lines.lines.len() == 2
+ && self.token == token::FatArrow => {
+ // We check whether there's any trailing code in the parse span,
+ // if there isn't, we very likely have the following:
+ //
+ // X | &Y => "y"
+ // | -- - missing comma
+ // | |
+ // | arrow_span
+ // X | &X => "x"
+ // | - ^^ self.token.span
+ // | |
+ // | parsed until here as `"y" & X`
+ err.span_suggestion_short(
+ cm.next_point(arm_start_span),
+ "missing a comma here to end this `match` arm",
+ ",".to_owned(),
+ Applicability::MachineApplicable
+ );
+ }
+ _ => {
+ err.span_label(arrow_span,
+ "while parsing the `match` arm starting here");
+ }
+ }
+ err
+ })?;
+ } else {
+ self.eat(&token::Comma);
+ }
+
+ Ok(ast::Arm {
+ attrs,
+ pats,
+ guard,
+ body: expr,
+ span: lo.to(hi),
+ })
+ }
+
+ /// Parses a `try {...}` expression (`try` token already eaten).
+ fn parse_try_block(
+ &mut self,
+ span_lo: Span,
+ mut attrs: ThinVec<Attribute>
+ ) -> PResult<'a, P<Expr>> {
+ let (iattrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(iattrs);
+ if self.eat_keyword(kw::Catch) {
+ let mut error = self.struct_span_err(self.prev_span,
+ "keyword `catch` cannot follow a `try` block");
+ error.help("try using `match` on the result of the `try` block instead");
+ error.emit();
+ Err(error)
+ } else {
+ Ok(self.mk_expr(span_lo.to(body.span), ExprKind::TryBlock(body), attrs))
+ }
+ }
+
+ fn is_do_catch_block(&self) -> bool {
+ self.token.is_keyword(kw::Do) &&
+ self.is_keyword_ahead(1, &[kw::Catch]) &&
+ self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) &&
+ !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
+ }
+
+ fn is_try_block(&self) -> bool {
+ self.token.is_keyword(kw::Try) &&
+ self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) &&
+ self.token.span.rust_2018() &&
+ // prevent `while try {} {}`, `if try {} {} else {}`, etc.
+ !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
+ }
+
+ /// Parses an `async move? {...}` expression.
+ pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
+ let span_lo = self.token.span;
+ self.expect_keyword(kw::Async)?;
+ let capture_clause = self.parse_capture_clause();
+ let (iattrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(iattrs);
+ Ok(self.mk_expr(
+ span_lo.to(body.span),
+ ExprKind::Async(capture_clause, ast::DUMMY_NODE_ID, body), attrs))
+ }
+
+ fn is_async_block(&self) -> bool {
+ self.token.is_keyword(kw::Async) &&
+ (
+ ( // `async move {`
+ self.is_keyword_ahead(1, &[kw::Move]) &&
+ self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))
+ ) || ( // `async {`
+ self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace))
+ )
+ )
+ }
+
+ fn maybe_parse_struct_expr(
+ &mut self,
+ lo: Span,
+ path: &ast::Path,
+ attrs: &ThinVec<Attribute>,
+ ) -> Option<PResult<'a, P<Expr>>> {
+ let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
+ let certainly_not_a_block = || self.look_ahead(1, |t| t.is_ident()) && (
+ // `{ ident, ` cannot start a block
+ self.look_ahead(2, |t| t == &token::Comma) ||
+ self.look_ahead(2, |t| t == &token::Colon) && (
+ // `{ ident: token, ` cannot start a block
+ self.look_ahead(4, |t| t == &token::Comma) ||
+ // `{ ident: ` cannot start a block unless it's a type ascription `ident: Type`
+ self.look_ahead(3, |t| !t.can_begin_type())
+ )
+ );
+
+ if struct_allowed || certainly_not_a_block() {
+ // This is a struct literal, but we don't can't accept them here
+ let expr = self.parse_struct_expr(lo, path.clone(), attrs.clone());
+ if let (Ok(expr), false) = (&expr, struct_allowed) {
+ self.struct_span_err(
+ expr.span,
+ "struct literals are not allowed here",
+ )
+ .multipart_suggestion(
+ "surround the struct literal with parentheses",
+ vec![
+ (lo.shrink_to_lo(), "(".to_string()),
+ (expr.span.shrink_to_hi(), ")".to_string()),
+ ],
+ Applicability::MachineApplicable,
+ )
+ .emit();
+ }
+ return Some(expr);
+ }
+ None
+ }
+
+ pub(super) fn parse_struct_expr(
+ &mut self,
+ lo: Span,
+ pth: ast::Path,
+ mut attrs: ThinVec<Attribute>
+ ) -> PResult<'a, P<Expr>> {
+ let struct_sp = lo.to(self.prev_span);
+ self.bump();
+ let mut fields = Vec::new();
+ let mut base = None;
+
+ attrs.extend(self.parse_inner_attributes()?);
+
+ while self.token != token::CloseDelim(token::Brace) {
+ if self.eat(&token::DotDot) {
+ let exp_span = self.prev_span;
+ match self.parse_expr() {
+ Ok(e) => {
+ base = Some(e);
+ }
+ Err(mut e) => {
+ e.emit();
+ self.recover_stmt();
+ }
+ }
+ if self.token == token::Comma {
+ self.struct_span_err(
+ exp_span.to(self.prev_span),
+ "cannot use a comma after the base struct",
+ )
+ .span_suggestion_short(
+ self.token.span,
+ "remove this comma",
+ String::new(),
+ Applicability::MachineApplicable
+ )
+ .note("the base struct must always be the last field")
+ .emit();
+ self.recover_stmt();
+ }
+ break;
+ }
+
+ let mut recovery_field = None;
+ if let token::Ident(name, _) = self.token.kind {
+ if !self.token.is_reserved_ident() && self.look_ahead(1, |t| *t == token::Colon) {
+ // Use in case of error after field-looking code: `S { foo: () with a }`
+ recovery_field = Some(ast::Field {
+ ident: Ident::new(name, self.token.span),
+ span: self.token.span,
+ expr: self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()),
+ is_shorthand: false,
+ attrs: ThinVec::new(),
+ });
+ }
+ }
+ let mut parsed_field = None;
+ match self.parse_field() {
+ Ok(f) => parsed_field = Some(f),
+ Err(mut e) => {
+ e.span_label(struct_sp, "while parsing this struct");
+ e.emit();
+
+ // If the next token is a comma, then try to parse
+ // what comes next as additional fields, rather than
+ // bailing out until next `}`.
+ if self.token != token::Comma {
+ self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
+ if self.token != token::Comma {
+ break;
+ }
+ }
+ }
+ }
+
+ match self.expect_one_of(&[token::Comma],
+ &[token::CloseDelim(token::Brace)]) {
+ Ok(_) => if let Some(f) = parsed_field.or(recovery_field) {
+ // only include the field if there's no parse error for the field name
+ fields.push(f);
+ }
+ Err(mut e) => {
+ if let Some(f) = recovery_field {
+ fields.push(f);
+ }
+ e.span_label(struct_sp, "while parsing this struct");
+ e.emit();
+ self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
+ self.eat(&token::Comma);
+ }
+ }
+ }
+
+ let span = lo.to(self.token.span);
+ self.expect(&token::CloseDelim(token::Brace))?;
+ return Ok(self.mk_expr(span, ExprKind::Struct(pth, fields, base), attrs));
+ }
+
+ /// Parse ident (COLON expr)?
+ fn parse_field(&mut self) -> PResult<'a, Field> {
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+
+ // Check if a colon exists one ahead. This means we're parsing a fieldname.
+ let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| {
+ t == &token::Colon || t == &token::Eq
+ }) {
+ let fieldname = self.parse_field_name()?;
+
+ // Check for an equals token. This means the source incorrectly attempts to
+ // initialize a field with an eq rather than a colon.
+ if self.token == token::Eq {
+ self.diagnostic()
+ .struct_span_err(self.token.span, "expected `:`, found `=`")
+ .span_suggestion(
+ fieldname.span.shrink_to_hi().to(self.token.span),
+ "replace equals symbol with a colon",
+ ":".to_string(),
+ Applicability::MachineApplicable,
+ )
+ .emit();
+ }
+ self.bump(); // `:`
+ (fieldname, self.parse_expr()?, false)
+ } else {
+ let fieldname = self.parse_ident_common(false)?;
+
+ // Mimic `x: x` for the `x` field shorthand.
+ let path = ast::Path::from_ident(fieldname);
+ let expr = self.mk_expr(fieldname.span, ExprKind::Path(None, path), ThinVec::new());
+ (fieldname, expr, true)
+ };
+ Ok(ast::Field {
+ ident: fieldname,
+ span: lo.to(expr.span),
+ expr,
+ is_shorthand,
+ attrs: attrs.into(),
+ })
+ }
+
+ fn err_dotdotdot_syntax(&self, span: Span) {
+ self.struct_span_err(span, "unexpected token: `...`")
+ .span_suggestion(
+ span,
+ "use `..` for an exclusive range", "..".to_owned(),
+ Applicability::MaybeIncorrect
+ )
+ .span_suggestion(
+ span,
+ "or `..=` for an inclusive range", "..=".to_owned(),
+ Applicability::MaybeIncorrect
+ )
+ .emit();
+ }
+
+ fn mk_assign_op(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
+ ExprKind::AssignOp(binop, lhs, rhs)
+ }
+
+ fn mk_range(
+ &self,
+ start: Option<P<Expr>>,
+ end: Option<P<Expr>>,
+ limits: RangeLimits
+ ) -> PResult<'a, ExprKind> {
+ if end.is_none() && limits == RangeLimits::Closed {
+ Err(self.span_fatal_err(self.token.span, Error::InclusiveRangeWithNoEnd))
+ } else {
+ Ok(ExprKind::Range(start, end, limits))
+ }
+ }
+
+ fn mk_unary(&self, unop: UnOp, expr: P<Expr>) -> ExprKind {
+ ExprKind::Unary(unop, expr)
+ }
+
+ fn mk_binary(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
+ ExprKind::Binary(binop, lhs, rhs)
+ }
+
+ fn mk_index(&self, expr: P<Expr>, idx: P<Expr>) -> ExprKind {
+ ExprKind::Index(expr, idx)
+ }
+
+ fn mk_call(&self, f: P<Expr>, args: Vec<P<Expr>>) -> ExprKind {
+ ExprKind::Call(f, args)
+ }
+
+ fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
+ let span = lo.to(self.prev_span);
+ let await_expr = self.mk_expr(span, ExprKind::Await(self_arg), ThinVec::new());
+ self.recover_from_await_method_call();
+ Ok(await_expr)
+ }
+
+ crate fn mk_expr(&self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> {
+ P(Expr { node, span, attrs, id: ast::DUMMY_NODE_ID })
+ }
+}
--- /dev/null
+use super::{Parser, PResult};
+
+use crate::ast::{self, WhereClause, GenericParam, GenericParamKind, GenericBounds, Attribute};
+use crate::parse::token;
+use crate::source_map::DUMMY_SP;
+use crate::symbol::kw;
+
+impl<'a> Parser<'a> {
+ /// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
+ ///
+ /// ```
+ /// BOUND = LT_BOUND (e.g., `'a`)
+ /// ```
+ fn parse_lt_param_bounds(&mut self) -> GenericBounds {
+ let mut lifetimes = Vec::new();
+ while self.check_lifetime() {
+ lifetimes.push(ast::GenericBound::Outlives(self.expect_lifetime()));
+
+ if !self.eat_plus() {
+ break
+ }
+ }
+ lifetimes
+ }
+
+ /// Matches `typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?`.
+ fn parse_ty_param(&mut self,
+ preceding_attrs: Vec<Attribute>)
+ -> PResult<'a, GenericParam> {
+ let ident = self.parse_ident()?;
+
+ // Parse optional colon and param bounds.
+ let bounds = if self.eat(&token::Colon) {
+ self.parse_generic_bounds(Some(self.prev_span))?
+ } else {
+ Vec::new()
+ };
+
+ let default = if self.eat(&token::Eq) {
+ Some(self.parse_ty()?)
+ } else {
+ None
+ };
+
+ Ok(GenericParam {
+ ident,
+ id: ast::DUMMY_NODE_ID,
+ attrs: preceding_attrs.into(),
+ bounds,
+ kind: GenericParamKind::Type {
+ default,
+ }
+ })
+ }
+
+ fn parse_const_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> {
+ self.expect_keyword(kw::Const)?;
+ let ident = self.parse_ident()?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+
+ Ok(GenericParam {
+ ident,
+ id: ast::DUMMY_NODE_ID,
+ attrs: preceding_attrs.into(),
+ bounds: Vec::new(),
+ kind: GenericParamKind::Const {
+ ty,
+ }
+ })
+ }
+
+ /// Parses a (possibly empty) list of lifetime and type parameters, possibly including
+ /// a trailing comma and erroneous trailing attributes.
+ crate fn parse_generic_params(&mut self) -> PResult<'a, Vec<ast::GenericParam>> {
+ let mut params = Vec::new();
+ loop {
+ let attrs = self.parse_outer_attributes()?;
+ if self.check_lifetime() {
+ let lifetime = self.expect_lifetime();
+ // Parse lifetime parameter.
+ let bounds = if self.eat(&token::Colon) {
+ self.parse_lt_param_bounds()
+ } else {
+ Vec::new()
+ };
+ params.push(ast::GenericParam {
+ ident: lifetime.ident,
+ id: lifetime.id,
+ attrs: attrs.into(),
+ bounds,
+ kind: ast::GenericParamKind::Lifetime,
+ });
+ } else if self.check_keyword(kw::Const) {
+ // Parse const parameter.
+ params.push(self.parse_const_param(attrs)?);
+ } else if self.check_ident() {
+ // Parse type parameter.
+ params.push(self.parse_ty_param(attrs)?);
+ } else {
+ // Check for trailing attributes and stop parsing.
+ if !attrs.is_empty() {
+ if !params.is_empty() {
+ self.struct_span_err(
+ attrs[0].span,
+ &format!("trailing attribute after generic parameter"),
+ )
+ .span_label(attrs[0].span, "attributes must go before parameters")
+ .emit();
+ } else {
+ self.struct_span_err(
+ attrs[0].span,
+ &format!("attribute without generic parameters"),
+ )
+ .span_label(
+ attrs[0].span,
+ "attributes are only permitted when preceding parameters",
+ )
+ .emit();
+ }
+ }
+ break
+ }
+
+ if !self.eat(&token::Comma) {
+ break
+ }
+ }
+ Ok(params)
+ }
+
+ /// Parses a set of optional generic type parameter declarations. Where
+ /// clauses are not parsed here, and must be added later via
+ /// `parse_where_clause()`.
+ ///
+ /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
+ /// | ( < lifetimes , typaramseq ( , )? > )
+ /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
+ pub(super) fn parse_generics(&mut self) -> PResult<'a, ast::Generics> {
+ let span_lo = self.token.span;
+ let (params, span) = if self.eat_lt() {
+ let params = self.parse_generic_params()?;
+ self.expect_gt()?;
+ (params, span_lo.to(self.prev_span))
+ } else {
+ (vec![], self.prev_span.between(self.token.span))
+ };
+ Ok(ast::Generics {
+ params,
+ where_clause: WhereClause {
+ predicates: Vec::new(),
+ span: DUMMY_SP,
+ },
+ span,
+ })
+ }
+
+ /// Parses an optional where-clause and places it in `generics`.
+ ///
+ /// ```ignore (only-for-syntax-highlight)
+ /// where T : Trait<U, V> + 'b, 'a : 'b
+ /// ```
+ pub(super) fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> {
+ let mut where_clause = WhereClause {
+ predicates: Vec::new(),
+ span: self.prev_span.to(self.prev_span),
+ };
+
+ if !self.eat_keyword(kw::Where) {
+ return Ok(where_clause);
+ }
+ let lo = self.prev_span;
+
+ // We are considering adding generics to the `where` keyword as an alternative higher-rank
+ // parameter syntax (as in `where<'a>` or `where<T>`. To avoid that being a breaking
+ // change we parse those generics now, but report an error.
+ if self.choose_generics_over_qpath() {
+ let generics = self.parse_generics()?;
+ self.struct_span_err(
+ generics.span,
+ "generic parameters on `where` clauses are reserved for future use",
+ )
+ .span_label(generics.span, "currently unsupported")
+ .emit();
+ }
+
+ loop {
+ let lo = self.token.span;
+ if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
+ let lifetime = self.expect_lifetime();
+ // Bounds starting with a colon are mandatory, but possibly empty.
+ self.expect(&token::Colon)?;
+ let bounds = self.parse_lt_param_bounds();
+ where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
+ ast::WhereRegionPredicate {
+ span: lo.to(self.prev_span),
+ lifetime,
+ bounds,
+ }
+ ));
+ } else if self.check_type() {
+ // Parse optional `for<'a, 'b>`.
+ // This `for` is parsed greedily and applies to the whole predicate,
+ // the bounded type can have its own `for` applying only to it.
+ // Examples:
+ // * `for<'a> Trait1<'a>: Trait2<'a /* ok */>`
+ // * `(for<'a> Trait1<'a>): Trait2<'a /* not ok */>`
+ // * `for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /* ok */, 'b /* not ok */>`
+ let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
+
+ // Parse type with mandatory colon and (possibly empty) bounds,
+ // or with mandatory equality sign and the second type.
+ let ty = self.parse_ty()?;
+ if self.eat(&token::Colon) {
+ let bounds = self.parse_generic_bounds(Some(self.prev_span))?;
+ where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
+ ast::WhereBoundPredicate {
+ span: lo.to(self.prev_span),
+ bound_generic_params: lifetime_defs,
+ bounded_ty: ty,
+ bounds,
+ }
+ ));
+ // FIXME: Decide what should be used here, `=` or `==`.
+ // FIXME: We are just dropping the binders in lifetime_defs on the floor here.
+ } else if self.eat(&token::Eq) || self.eat(&token::EqEq) {
+ let rhs_ty = self.parse_ty()?;
+ where_clause.predicates.push(ast::WherePredicate::EqPredicate(
+ ast::WhereEqPredicate {
+ span: lo.to(self.prev_span),
+ lhs_ty: ty,
+ rhs_ty,
+ id: ast::DUMMY_NODE_ID,
+ }
+ ));
+ } else {
+ return self.unexpected();
+ }
+ } else {
+ break
+ }
+
+ if !self.eat(&token::Comma) {
+ break
+ }
+ }
+
+ where_clause.span = lo.to(self.prev_span);
+ Ok(where_clause)
+ }
+
+ pub(super) fn choose_generics_over_qpath(&self) -> bool {
+ // There's an ambiguity between generic parameters and qualified paths in impls.
+ // If we see `<` it may start both, so we have to inspect some following tokens.
+ // The following combinations can only start generics,
+ // but not qualified paths (with one exception):
+ // `<` `>` - empty generic parameters
+ // `<` `#` - generic parameters with attributes
+ // `<` (LIFETIME|IDENT) `>` - single generic parameter
+ // `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
+ // `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
+ // `<` (LIFETIME|IDENT) `=` - generic parameter with a default
+ // `<` const - generic const parameter
+ // The only truly ambiguous case is
+ // `<` IDENT `>` `::` IDENT ...
+ // we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
+ // because this is what almost always expected in practice, qualified paths in impls
+ // (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment.
+ self.token == token::Lt &&
+ (self.look_ahead(1, |t| t == &token::Pound || t == &token::Gt) ||
+ self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) &&
+ self.look_ahead(2, |t| t == &token::Gt || t == &token::Comma ||
+ t == &token::Colon || t == &token::Eq) ||
+ self.is_keyword_ahead(1, &[kw::Const]))
+ }
+}
--- /dev/null
+use super::{Parser, PResult, PathStyle, SemiColonMode, BlockMode};
+
+use crate::maybe_whole;
+use crate::ptr::P;
+use crate::ast::{self, Ident, Attribute, AttrStyle};
+use crate::ast::{Item, ItemKind, ImplItem, TraitItem, TraitItemKind};
+use crate::ast::{UseTree, UseTreeKind, PathSegment};
+use crate::ast::{IsAuto, Constness, IsAsync, Unsafety, Defaultness};
+use crate::ast::{Visibility, VisibilityKind, Mutability, FnDecl, FnHeader};
+use crate::ast::{ForeignItem, ForeignItemKind};
+use crate::ast::{Ty, TyKind, GenericBounds, TraitRef};
+use crate::ast::{EnumDef, VariantData, StructField, AnonConst};
+use crate::ast::{Mac, Mac_, MacDelimiter};
+use crate::ext::base::DummyResult;
+use crate::parse::token;
+use crate::parse::parser::maybe_append;
+use crate::parse::diagnostics::{Error};
+use crate::tokenstream::{TokenTree, TokenStream};
+use crate::source_map::{respan, Span, Spanned};
+use crate::symbol::{kw, sym};
+
+use std::mem;
+use log::debug;
+use rustc_target::spec::abi::{Abi};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+
+/// Whether the type alias or associated type is a concrete type or an opaque type
+#[derive(Debug)]
+pub enum AliasKind {
+ /// Just a new name for the same type
+ Weak(P<Ty>),
+ /// Only trait impls of the type will be usable, not the actual type itself
+ OpaqueTy(GenericBounds),
+}
+
+pub(super) type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute>>);
+
+impl<'a> Parser<'a> {
+ pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
+ let attrs = self.parse_outer_attributes()?;
+ self.parse_item_(attrs, true, false)
+ }
+
+ pub(super) fn parse_item_(
+ &mut self,
+ attrs: Vec<Attribute>,
+ macros_allowed: bool,
+ attributes_allowed: bool,
+ ) -> PResult<'a, Option<P<Item>>> {
+ let mut unclosed_delims = vec![];
+ let (ret, tokens) = self.collect_tokens(|this| {
+ let item = this.parse_item_implementation(attrs, macros_allowed, attributes_allowed);
+ unclosed_delims.append(&mut this.unclosed_delims);
+ item
+ })?;
+ self.unclosed_delims.append(&mut unclosed_delims);
+
+ // Once we've parsed an item and recorded the tokens we got while
+ // parsing we may want to store `tokens` into the item we're about to
+ // return. Note, though, that we specifically didn't capture tokens
+ // related to outer attributes. The `tokens` field here may later be
+ // used with procedural macros to convert this item back into a token
+ // stream, but during expansion we may be removing attributes as we go
+ // along.
+ //
+ // If we've got inner attributes then the `tokens` we've got above holds
+ // these inner attributes. If an inner attribute is expanded we won't
+ // actually remove it from the token stream, so we'll just keep yielding
+ // it (bad!). To work around this case for now we just avoid recording
+ // `tokens` if we detect any inner attributes. This should help keep
+ // expansion correct, but we should fix this bug one day!
+ Ok(ret.map(|item| {
+ item.map(|mut i| {
+ if !i.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
+ i.tokens = Some(tokens);
+ }
+ i
+ })
+ }))
+ }
+
+ /// Parses one of the items allowed by the flags.
+ fn parse_item_implementation(
+ &mut self,
+ attrs: Vec<Attribute>,
+ macros_allowed: bool,
+ attributes_allowed: bool,
+ ) -> PResult<'a, Option<P<Item>>> {
+ maybe_whole!(self, NtItem, |item| {
+ let mut item = item.into_inner();
+ let mut attrs = attrs;
+ mem::swap(&mut item.attrs, &mut attrs);
+ item.attrs.extend(attrs);
+ Some(P(item))
+ });
+
+ let lo = self.token.span;
+
+ let visibility = self.parse_visibility(false)?;
+
+ if self.eat_keyword(kw::Use) {
+ // USE ITEM
+ let item_ = ItemKind::Use(P(self.parse_use_tree()?));
+ self.expect(&token::Semi)?;
+
+ let span = lo.to(self.prev_span);
+ let item =
+ self.mk_item(span, Ident::invalid(), item_, visibility, attrs);
+ return Ok(Some(item));
+ }
+
+ if self.eat_keyword(kw::Extern) {
+ let extern_sp = self.prev_span;
+ if self.eat_keyword(kw::Crate) {
+ return Ok(Some(self.parse_item_extern_crate(lo, visibility, attrs)?));
+ }
+
+ let opt_abi = self.parse_opt_abi()?;
+
+ if self.eat_keyword(kw::Fn) {
+ // EXTERN FUNCTION ITEM
+ let fn_span = self.prev_span;
+ let abi = opt_abi.unwrap_or(Abi::C);
+ let (ident, item_, extra_attrs) =
+ self.parse_item_fn(Unsafety::Normal,
+ respan(fn_span, IsAsync::NotAsync),
+ respan(fn_span, Constness::NotConst),
+ abi)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ return Ok(Some(
+ self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs, extern_sp)?,
+ ));
+ }
+
+ self.unexpected()?;
+ }
+
+ if self.is_static_global() {
+ self.bump();
+ // STATIC ITEM
+ let m = self.parse_mutability();
+ let (ident, item_, extra_attrs) = self.parse_item_const(Some(m))?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.eat_keyword(kw::Const) {
+ let const_span = self.prev_span;
+ if self.check_keyword(kw::Fn)
+ || (self.check_keyword(kw::Unsafe)
+ && self.is_keyword_ahead(1, &[kw::Fn])) {
+ // CONST FUNCTION ITEM
+ let unsafety = self.parse_unsafety();
+ self.bump();
+ let (ident, item_, extra_attrs) =
+ self.parse_item_fn(unsafety,
+ respan(const_span, IsAsync::NotAsync),
+ respan(const_span, Constness::Const),
+ Abi::Rust)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+
+ // CONST ITEM
+ if self.eat_keyword(kw::Mut) {
+ let prev_span = self.prev_span;
+ self.struct_span_err(prev_span, "const globals cannot be mutable")
+ .span_label(prev_span, "cannot be mutable")
+ .span_suggestion(
+ const_span,
+ "you might want to declare a static instead",
+ "static".to_owned(),
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ }
+ let (ident, item_, extra_attrs) = self.parse_item_const(None)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+
+ // Parse `async unsafe? fn`.
+ if self.check_keyword(kw::Async) {
+ let async_span = self.token.span;
+ if self.is_keyword_ahead(1, &[kw::Fn])
+ || self.is_keyword_ahead(2, &[kw::Fn])
+ {
+ // ASYNC FUNCTION ITEM
+ self.bump(); // `async`
+ let unsafety = self.parse_unsafety(); // `unsafe`?
+ self.expect_keyword(kw::Fn)?; // `fn`
+ let fn_span = self.prev_span;
+ let (ident, item_, extra_attrs) =
+ self.parse_item_fn(unsafety,
+ respan(async_span, IsAsync::Async {
+ closure_id: ast::DUMMY_NODE_ID,
+ return_impl_trait_id: ast::DUMMY_NODE_ID,
+ }),
+ respan(fn_span, Constness::NotConst),
+ Abi::Rust)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ self.ban_async_in_2015(async_span);
+ return Ok(Some(item));
+ }
+ }
+ if self.check_keyword(kw::Unsafe) &&
+ self.is_keyword_ahead(1, &[kw::Trait, kw::Auto])
+ {
+ // UNSAFE TRAIT ITEM
+ self.bump(); // `unsafe`
+ let is_auto = if self.eat_keyword(kw::Trait) {
+ IsAuto::No
+ } else {
+ self.expect_keyword(kw::Auto)?;
+ self.expect_keyword(kw::Trait)?;
+ IsAuto::Yes
+ };
+ let (ident, item_, extra_attrs) =
+ self.parse_item_trait(is_auto, Unsafety::Unsafe)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.check_keyword(kw::Impl) ||
+ self.check_keyword(kw::Unsafe) &&
+ self.is_keyword_ahead(1, &[kw::Impl]) ||
+ self.check_keyword(kw::Default) &&
+ self.is_keyword_ahead(1, &[kw::Impl, kw::Unsafe]) {
+ // IMPL ITEM
+ let defaultness = self.parse_defaultness();
+ let unsafety = self.parse_unsafety();
+ self.expect_keyword(kw::Impl)?;
+ let (ident, item, extra_attrs) = self.parse_item_impl(unsafety, defaultness)?;
+ let span = lo.to(self.prev_span);
+ return Ok(Some(self.mk_item(span, ident, item, visibility,
+ maybe_append(attrs, extra_attrs))));
+ }
+ if self.check_keyword(kw::Fn) {
+ // FUNCTION ITEM
+ self.bump();
+ let fn_span = self.prev_span;
+ let (ident, item_, extra_attrs) =
+ self.parse_item_fn(Unsafety::Normal,
+ respan(fn_span, IsAsync::NotAsync),
+ respan(fn_span, Constness::NotConst),
+ Abi::Rust)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.check_keyword(kw::Unsafe)
+ && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
+ // UNSAFE FUNCTION ITEM
+ self.bump(); // `unsafe`
+ // `{` is also expected after `unsafe`, in case of error, include it in the diagnostic
+ self.check(&token::OpenDelim(token::Brace));
+ let abi = if self.eat_keyword(kw::Extern) {
+ self.parse_opt_abi()?.unwrap_or(Abi::C)
+ } else {
+ Abi::Rust
+ };
+ self.expect_keyword(kw::Fn)?;
+ let fn_span = self.prev_span;
+ let (ident, item_, extra_attrs) =
+ self.parse_item_fn(Unsafety::Unsafe,
+ respan(fn_span, IsAsync::NotAsync),
+ respan(fn_span, Constness::NotConst),
+ abi)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.eat_keyword(kw::Mod) {
+ // MODULE ITEM
+ let (ident, item_, extra_attrs) =
+ self.parse_item_mod(&attrs[..])?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if let Some(type_) = self.eat_type() {
+ let (ident, alias, generics) = type_?;
+ // TYPE ITEM
+ let item_ = match alias {
+ AliasKind::Weak(ty) => ItemKind::TyAlias(ty, generics),
+ AliasKind::OpaqueTy(bounds) => ItemKind::OpaqueTy(bounds, generics),
+ };
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ attrs);
+ return Ok(Some(item));
+ }
+ if self.eat_keyword(kw::Enum) {
+ // ENUM ITEM
+ let (ident, item_, extra_attrs) = self.parse_item_enum()?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.check_keyword(kw::Trait)
+ || (self.check_keyword(kw::Auto)
+ && self.is_keyword_ahead(1, &[kw::Trait]))
+ {
+ let is_auto = if self.eat_keyword(kw::Trait) {
+ IsAuto::No
+ } else {
+ self.expect_keyword(kw::Auto)?;
+ self.expect_keyword(kw::Trait)?;
+ IsAuto::Yes
+ };
+ // TRAIT ITEM
+ let (ident, item_, extra_attrs) =
+ self.parse_item_trait(is_auto, Unsafety::Normal)?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.eat_keyword(kw::Struct) {
+ // STRUCT ITEM
+ let (ident, item_, extra_attrs) = self.parse_item_struct()?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if self.is_union_item() {
+ // UNION ITEM
+ self.bump();
+ let (ident, item_, extra_attrs) = self.parse_item_union()?;
+ let prev_span = self.prev_span;
+ let item = self.mk_item(lo.to(prev_span),
+ ident,
+ item_,
+ visibility,
+ maybe_append(attrs, extra_attrs));
+ return Ok(Some(item));
+ }
+ if let Some(macro_def) = self.eat_macro_def(&attrs, &visibility, lo)? {
+ return Ok(Some(macro_def));
+ }
+
+ // Verify whether we have encountered a struct or method definition where the user forgot to
+ // add the `struct` or `fn` keyword after writing `pub`: `pub S {}`
+ if visibility.node.is_pub() &&
+ self.check_ident() &&
+ self.look_ahead(1, |t| *t != token::Not)
+ {
+ // Space between `pub` keyword and the identifier
+ //
+ // pub S {}
+ // ^^^ `sp` points here
+ let sp = self.prev_span.between(self.token.span);
+ let full_sp = self.prev_span.to(self.token.span);
+ let ident_sp = self.token.span;
+ if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) {
+ // possible public struct definition where `struct` was forgotten
+ let ident = self.parse_ident().unwrap();
+ let msg = format!("add `struct` here to parse `{}` as a public struct",
+ ident);
+ let mut err = self.diagnostic()
+ .struct_span_err(sp, "missing `struct` for struct definition");
+ err.span_suggestion_short(
+ sp, &msg, " struct ".into(), Applicability::MaybeIncorrect // speculative
+ );
+ return Err(err);
+ } else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) {
+ let ident = self.parse_ident().unwrap();
+ self.bump(); // `(`
+ let kw_name = if let Ok(Some(_)) = self.parse_self_arg_with_attrs()
+ .map_err(|mut e| e.cancel())
+ {
+ "method"
+ } else {
+ "function"
+ };
+ self.consume_block(token::Paren);
+ let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) {
+ self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]);
+ self.bump(); // `{`
+ ("fn", kw_name, false)
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ self.bump(); // `{`
+ ("fn", kw_name, false)
+ } else if self.check(&token::Colon) {
+ let kw = "struct";
+ (kw, kw, false)
+ } else {
+ ("fn` or `struct", "function or struct", true)
+ };
+
+ let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let mut err = self.diagnostic().struct_span_err(sp, &msg);
+ if !ambiguous {
+ self.consume_block(token::Brace);
+ let suggestion = format!("add `{}` here to parse `{}` as a public {}",
+ kw,
+ ident,
+ kw_name);
+ err.span_suggestion_short(
+ sp, &suggestion, format!(" {} ", kw), Applicability::MachineApplicable
+ );
+ } else {
+ if let Ok(snippet) = self.span_to_snippet(ident_sp) {
+ err.span_suggestion(
+ full_sp,
+ "if you meant to call a macro, try",
+ format!("{}!", snippet),
+ // this is the `ambiguous` conditional branch
+ Applicability::MaybeIncorrect
+ );
+ } else {
+ err.help("if you meant to call a macro, remove the `pub` \
+ and add a trailing `!` after the identifier");
+ }
+ }
+ return Err(err);
+ } else if self.look_ahead(1, |t| *t == token::Lt) {
+ let ident = self.parse_ident().unwrap();
+ self.eat_to_tokens(&[&token::Gt]);
+ self.bump(); // `>`
+ let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) {
+ if let Ok(Some(_)) = self.parse_self_arg_with_attrs()
+ .map_err(|mut e| e.cancel())
+ {
+ ("fn", "method", false)
+ } else {
+ ("fn", "function", false)
+ }
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ ("struct", "struct", false)
+ } else {
+ ("fn` or `struct", "function or struct", true)
+ };
+ let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let mut err = self.diagnostic().struct_span_err(sp, &msg);
+ if !ambiguous {
+ err.span_suggestion_short(
+ sp,
+ &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
+ format!(" {} ", kw),
+ Applicability::MachineApplicable,
+ );
+ }
+ return Err(err);
+ }
+ }
+ self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility)
+ }
+
+ /// This is the fall-through for parsing items.
+ fn parse_macro_use_or_failure(
+ &mut self,
+ attrs: Vec<Attribute> ,
+ macros_allowed: bool,
+ attributes_allowed: bool,
+ lo: Span,
+ visibility: Visibility
+ ) -> PResult<'a, Option<P<Item>>> {
+ if macros_allowed && self.token.is_path_start() &&
+ !(self.is_async_fn() && self.token.span.rust_2015()) {
+ // MACRO INVOCATION ITEM
+
+ let prev_span = self.prev_span;
+ self.complain_if_pub_macro(&visibility.node, prev_span);
+
+ let mac_lo = self.token.span;
+
+ // item macro.
+ let path = self.parse_path(PathStyle::Mod)?;
+ self.expect(&token::Not)?;
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ if delim != MacDelimiter::Brace && !self.eat(&token::Semi) {
+ self.report_invalid_macro_expansion_item();
+ }
+
+ let hi = self.prev_span;
+ let mac = respan(mac_lo.to(hi), Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ });
+ let item =
+ self.mk_item(lo.to(hi), Ident::invalid(), ItemKind::Mac(mac), visibility, attrs);
+ return Ok(Some(item));
+ }
+
+ // FAILURE TO PARSE ITEM
+ match visibility.node {
+ VisibilityKind::Inherited => {}
+ _ => {
+ return Err(self.span_fatal(self.prev_span, "unmatched visibility `pub`"));
+ }
+ }
+
+ if !attributes_allowed && !attrs.is_empty() {
+ self.expected_item_err(&attrs)?;
+ }
+ Ok(None)
+ }
+
+ /// Emits an expected-item-after-attributes error.
+ fn expected_item_err(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
+ let message = match attrs.last() {
+ Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment",
+ _ => "expected item after attributes",
+ };
+
+ let mut err = self.diagnostic().struct_span_err(self.prev_span, message);
+ if attrs.last().unwrap().is_sugared_doc {
+ err.span_label(self.prev_span, "this doc comment doesn't document anything");
+ }
+ Err(err)
+ }
+
+ pub(super) fn is_async_fn(&self) -> bool {
+ self.token.is_keyword(kw::Async) &&
+ self.is_keyword_ahead(1, &[kw::Fn])
+ }
+
+ /// Parses a macro invocation inside a `trait`, `impl` or `extern` block.
+ fn parse_assoc_macro_invoc(&mut self, item_kind: &str, vis: Option<&Visibility>,
+ at_end: &mut bool) -> PResult<'a, Option<Mac>>
+ {
+ if self.token.is_path_start() &&
+ !(self.is_async_fn() && self.token.span.rust_2015()) {
+ let prev_span = self.prev_span;
+ let lo = self.token.span;
+ let path = self.parse_path(PathStyle::Mod)?;
+
+ if path.segments.len() == 1 {
+ if !self.eat(&token::Not) {
+ return Err(self.missing_assoc_item_kind_err(item_kind, prev_span));
+ }
+ } else {
+ self.expect(&token::Not)?;
+ }
+
+ if let Some(vis) = vis {
+ self.complain_if_pub_macro(&vis.node, prev_span);
+ }
+
+ *at_end = true;
+
+ // eat a matched-delimiter token tree:
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ if delim != MacDelimiter::Brace {
+ self.expect(&token::Semi)?;
+ }
+
+ Ok(Some(respan(lo.to(self.prev_span), Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ })))
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn missing_assoc_item_kind_err(&self, item_type: &str, prev_span: Span)
+ -> DiagnosticBuilder<'a>
+ {
+ let expected_kinds = if item_type == "extern" {
+ "missing `fn`, `type`, or `static`"
+ } else {
+ "missing `fn`, `type`, or `const`"
+ };
+
+ // Given this code `path(`, it seems like this is not
+ // setting the visibility of a macro invocation, but rather
+ // a mistyped method declaration.
+ // Create a diagnostic pointing out that `fn` is missing.
+ //
+ // x | pub path(&self) {
+ // | ^ missing `fn`, `type`, or `const`
+ // pub path(
+ // ^^ `sp` below will point to this
+ let sp = prev_span.between(self.prev_span);
+ let mut err = self.diagnostic().struct_span_err(
+ sp,
+ &format!("{} for {}-item declaration",
+ expected_kinds, item_type));
+ err.span_label(sp, expected_kinds);
+ err
+ }
+
+ /// Parses an implementation item, `impl` keyword is already parsed.
+ ///
+ /// impl<'a, T> TYPE { /* impl items */ }
+ /// impl<'a, T> TRAIT for TYPE { /* impl items */ }
+ /// impl<'a, T> !TRAIT for TYPE { /* impl items */ }
+ ///
+ /// We actually parse slightly more relaxed grammar for better error reporting and recovery.
+ /// `impl` GENERICS `!`? TYPE `for`? (TYPE | `..`) (`where` PREDICATES)? `{` BODY `}`
+ /// `impl` GENERICS `!`? TYPE (`where` PREDICATES)? `{` BODY `}`
+ fn parse_item_impl(&mut self, unsafety: Unsafety, defaultness: Defaultness)
+ -> PResult<'a, ItemInfo> {
+ // First, parse generic parameters if necessary.
+ let mut generics = if self.choose_generics_over_qpath() {
+ self.parse_generics()?
+ } else {
+ ast::Generics::default()
+ };
+
+ // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
+ let polarity = if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
+ self.bump(); // `!`
+ ast::ImplPolarity::Negative
+ } else {
+ ast::ImplPolarity::Positive
+ };
+
+ // Parse both types and traits as a type, then reinterpret if necessary.
+ let err_path = |span| ast::Path::from_ident(Ident::new(kw::Invalid, span));
+ let ty_first = if self.token.is_keyword(kw::For) &&
+ self.look_ahead(1, |t| t != &token::Lt) {
+ let span = self.prev_span.between(self.token.span);
+ self.struct_span_err(span, "missing trait in a trait impl").emit();
+ P(Ty { node: TyKind::Path(None, err_path(span)), span, id: ast::DUMMY_NODE_ID })
+ } else {
+ self.parse_ty()?
+ };
+
+ // If `for` is missing we try to recover.
+ let has_for = self.eat_keyword(kw::For);
+ let missing_for_span = self.prev_span.between(self.token.span);
+
+ let ty_second = if self.token == token::DotDot {
+ // We need to report this error after `cfg` expansion for compatibility reasons
+ self.bump(); // `..`, do not add it to expected tokens
+ Some(DummyResult::raw_ty(self.prev_span, true))
+ } else if has_for || self.token.can_begin_type() {
+ Some(self.parse_ty()?)
+ } else {
+ None
+ };
+
+ generics.where_clause = self.parse_where_clause()?;
+
+ let (impl_items, attrs) = self.parse_impl_body()?;
+
+ let item_kind = match ty_second {
+ Some(ty_second) => {
+ // impl Trait for Type
+ if !has_for {
+ self.struct_span_err(missing_for_span, "missing `for` in a trait impl")
+ .span_suggestion_short(
+ missing_for_span,
+ "add `for` here",
+ " for ".to_string(),
+ Applicability::MachineApplicable,
+ ).emit();
+ }
+
+ let ty_first = ty_first.into_inner();
+ let path = match ty_first.node {
+ // This notably includes paths passed through `ty` macro fragments (#46438).
+ TyKind::Path(None, path) => path,
+ _ => {
+ self.span_err(ty_first.span, "expected a trait, found type");
+ err_path(ty_first.span)
+ }
+ };
+ let trait_ref = TraitRef { path, ref_id: ty_first.id };
+
+ ItemKind::Impl(unsafety, polarity, defaultness,
+ generics, Some(trait_ref), ty_second, impl_items)
+ }
+ None => {
+ // impl Type
+ ItemKind::Impl(unsafety, polarity, defaultness,
+ generics, None, ty_first, impl_items)
+ }
+ };
+
+ Ok((Ident::invalid(), item_kind, Some(attrs)))
+ }
+
+ fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> {
+ self.expect(&token::OpenDelim(token::Brace))?;
+ let attrs = self.parse_inner_attributes()?;
+
+ let mut impl_items = Vec::new();
+ while !self.eat(&token::CloseDelim(token::Brace)) {
+ let mut at_end = false;
+ match self.parse_impl_item(&mut at_end) {
+ Ok(impl_item) => impl_items.push(impl_item),
+ Err(mut err) => {
+ err.emit();
+ if !at_end {
+ self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
+ }
+ }
+ }
+ }
+ Ok((impl_items, attrs))
+ }
+
+ /// Parses an impl item.
+ pub fn parse_impl_item(&mut self, at_end: &mut bool) -> PResult<'a, ImplItem> {
+ maybe_whole!(self, NtImplItem, |x| x);
+ let attrs = self.parse_outer_attributes()?;
+ let mut unclosed_delims = vec![];
+ let (mut item, tokens) = self.collect_tokens(|this| {
+ let item = this.parse_impl_item_(at_end, attrs);
+ unclosed_delims.append(&mut this.unclosed_delims);
+ item
+ })?;
+ self.unclosed_delims.append(&mut unclosed_delims);
+
+ // See `parse_item` for why this clause is here.
+ if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
+ item.tokens = Some(tokens);
+ }
+ Ok(item)
+ }
+
+ fn parse_impl_item_(&mut self,
+ at_end: &mut bool,
+ mut attrs: Vec<Attribute>) -> PResult<'a, ImplItem> {
+ let lo = self.token.span;
+ let vis = self.parse_visibility(false)?;
+ let defaultness = self.parse_defaultness();
+ let (name, node, generics) = if let Some(type_) = self.eat_type() {
+ let (name, alias, generics) = type_?;
+ let kind = match alias {
+ AliasKind::Weak(typ) => ast::ImplItemKind::TyAlias(typ),
+ AliasKind::OpaqueTy(bounds) => ast::ImplItemKind::OpaqueTy(bounds),
+ };
+ (name, kind, generics)
+ } else if self.is_const_item() {
+ // This parses the grammar:
+ // ImplItemConst = "const" Ident ":" Ty "=" Expr ";"
+ self.expect_keyword(kw::Const)?;
+ let name = self.parse_ident()?;
+ self.expect(&token::Colon)?;
+ let typ = self.parse_ty()?;
+ self.expect(&token::Eq)?;
+ let expr = self.parse_expr()?;
+ self.expect(&token::Semi)?;
+ (name, ast::ImplItemKind::Const(typ, expr), ast::Generics::default())
+ } else {
+ let (name, inner_attrs, generics, node) = self.parse_impl_method(&vis, at_end)?;
+ attrs.extend(inner_attrs);
+ (name, node, generics)
+ };
+
+ Ok(ImplItem {
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(self.prev_span),
+ ident: name,
+ vis,
+ defaultness,
+ attrs,
+ generics,
+ node,
+ tokens: None,
+ })
+ }
+
+ /// Parses defaultness (i.e., `default` or nothing).
+ fn parse_defaultness(&mut self) -> Defaultness {
+ // `pub` is included for better error messages
+ if self.check_keyword(kw::Default) &&
+ self.is_keyword_ahead(1, &[
+ kw::Impl,
+ kw::Const,
+ kw::Fn,
+ kw::Unsafe,
+ kw::Extern,
+ kw::Type,
+ kw::Pub,
+ ])
+ {
+ self.bump(); // `default`
+ Defaultness::Default
+ } else {
+ Defaultness::Final
+ }
+ }
+
+ /// Returns `true` if we are looking at `const ID`
+ /// (returns `false` for things like `const fn`, etc.).
+ fn is_const_item(&self) -> bool {
+ self.token.is_keyword(kw::Const) &&
+ !self.is_keyword_ahead(1, &[kw::Fn, kw::Unsafe])
+ }
+
+ /// Parse a method or a macro invocation in a trait impl.
+ fn parse_impl_method(&mut self, vis: &Visibility, at_end: &mut bool)
+ -> PResult<'a, (Ident, Vec<Attribute>, ast::Generics,
+ ast::ImplItemKind)> {
+ // code copied from parse_macro_use_or_failure... abstraction!
+ if let Some(mac) = self.parse_assoc_macro_invoc("impl", Some(vis), at_end)? {
+ // method macro
+ Ok((Ident::invalid(), vec![], ast::Generics::default(),
+ ast::ImplItemKind::Macro(mac)))
+ } else {
+ let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
+ let ident = self.parse_ident()?;
+ let mut generics = self.parse_generics()?;
+ let decl = self.parse_fn_decl_with_self(|p| {
+ p.parse_arg_general(true, false, |_| true)
+ })?;
+ generics.where_clause = self.parse_where_clause()?;
+ *at_end = true;
+ let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
+ let header = ast::FnHeader { abi, unsafety, constness, asyncness };
+ Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method(
+ ast::MethodSig { header, decl },
+ body
+ )))
+ }
+ }
+
+ /// Parses all the "front matter" for a `fn` declaration, up to
+ /// and including the `fn` keyword:
+ ///
+ /// - `const fn`
+ /// - `unsafe fn`
+ /// - `const unsafe fn`
+ /// - `extern fn`
+ /// - etc.
+ fn parse_fn_front_matter(&mut self)
+ -> PResult<'a, (
+ Spanned<Constness>,
+ Unsafety,
+ Spanned<IsAsync>,
+ Abi
+ )>
+ {
+ let is_const_fn = self.eat_keyword(kw::Const);
+ let const_span = self.prev_span;
+ let asyncness = self.parse_asyncness();
+ if let IsAsync::Async { .. } = asyncness {
+ self.ban_async_in_2015(self.prev_span);
+ }
+ let asyncness = respan(self.prev_span, asyncness);
+ let unsafety = self.parse_unsafety();
+ let (constness, unsafety, abi) = if is_const_fn {
+ (respan(const_span, Constness::Const), unsafety, Abi::Rust)
+ } else {
+ let abi = if self.eat_keyword(kw::Extern) {
+ self.parse_opt_abi()?.unwrap_or(Abi::C)
+ } else {
+ Abi::Rust
+ };
+ (respan(self.prev_span, Constness::NotConst), unsafety, abi)
+ };
+ if !self.eat_keyword(kw::Fn) {
+ // It is possible for `expect_one_of` to recover given the contents of
+ // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't
+ // account for this.
+ if !self.expect_one_of(&[], &[])? { unreachable!() }
+ }
+ Ok((constness, unsafety, asyncness, abi))
+ }
+
+ /// Parses `trait Foo { ... }` or `trait Foo = Bar;`.
+ fn parse_item_trait(&mut self, is_auto: IsAuto, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
+ let ident = self.parse_ident()?;
+ let mut tps = self.parse_generics()?;
+
+ // Parse optional colon and supertrait bounds.
+ let bounds = if self.eat(&token::Colon) {
+ self.parse_generic_bounds(Some(self.prev_span))?
+ } else {
+ Vec::new()
+ };
+
+ if self.eat(&token::Eq) {
+ // it's a trait alias
+ let bounds = self.parse_generic_bounds(None)?;
+ tps.where_clause = self.parse_where_clause()?;
+ self.expect(&token::Semi)?;
+ if is_auto == IsAuto::Yes {
+ let msg = "trait aliases cannot be `auto`";
+ self.struct_span_err(self.prev_span, msg)
+ .span_label(self.prev_span, msg)
+ .emit();
+ }
+ if unsafety != Unsafety::Normal {
+ let msg = "trait aliases cannot be `unsafe`";
+ self.struct_span_err(self.prev_span, msg)
+ .span_label(self.prev_span, msg)
+ .emit();
+ }
+ Ok((ident, ItemKind::TraitAlias(tps, bounds), None))
+ } else {
+ // it's a normal trait
+ tps.where_clause = self.parse_where_clause()?;
+ self.expect(&token::OpenDelim(token::Brace))?;
+ let mut trait_items = vec![];
+ while !self.eat(&token::CloseDelim(token::Brace)) {
+ if let token::DocComment(_) = self.token.kind {
+ if self.look_ahead(1,
+ |tok| tok == &token::CloseDelim(token::Brace)) {
+ self.diagnostic().struct_span_err_with_code(
+ self.token.span,
+ "found a documentation comment that doesn't document anything",
+ DiagnosticId::Error("E0584".into()),
+ )
+ .help(
+ "doc comments must come before what they document, maybe a \
+ comment was intended with `//`?",
+ )
+ .emit();
+ self.bump();
+ continue;
+ }
+ }
+ let mut at_end = false;
+ match self.parse_trait_item(&mut at_end) {
+ Ok(item) => trait_items.push(item),
+ Err(mut e) => {
+ e.emit();
+ if !at_end {
+ self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
+ }
+ }
+ }
+ }
+ Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
+ }
+ }
+
+ /// Parses the items in a trait declaration.
+ pub fn parse_trait_item(&mut self, at_end: &mut bool) -> PResult<'a, TraitItem> {
+ maybe_whole!(self, NtTraitItem, |x| x);
+ let attrs = self.parse_outer_attributes()?;
+ let mut unclosed_delims = vec![];
+ let (mut item, tokens) = self.collect_tokens(|this| {
+ let item = this.parse_trait_item_(at_end, attrs);
+ unclosed_delims.append(&mut this.unclosed_delims);
+ item
+ })?;
+ self.unclosed_delims.append(&mut unclosed_delims);
+ // See `parse_item` for why this clause is here.
+ if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
+ item.tokens = Some(tokens);
+ }
+ Ok(item)
+ }
+
+ fn parse_trait_item_(&mut self,
+ at_end: &mut bool,
+ mut attrs: Vec<Attribute>) -> PResult<'a, TraitItem> {
+ let lo = self.token.span;
+ self.eat_bad_pub();
+ let (name, node, generics) = if self.eat_keyword(kw::Type) {
+ self.parse_trait_item_assoc_ty()?
+ } else if self.is_const_item() {
+ self.expect_keyword(kw::Const)?;
+ let ident = self.parse_ident()?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+ let default = if self.eat(&token::Eq) {
+ let expr = self.parse_expr()?;
+ self.expect(&token::Semi)?;
+ Some(expr)
+ } else {
+ self.expect(&token::Semi)?;
+ None
+ };
+ (ident, TraitItemKind::Const(ty, default), ast::Generics::default())
+ } else if let Some(mac) = self.parse_assoc_macro_invoc("trait", None, &mut false)? {
+ // trait item macro.
+ (Ident::invalid(), ast::TraitItemKind::Macro(mac), ast::Generics::default())
+ } else {
+ let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?;
+
+ let ident = self.parse_ident()?;
+ let mut generics = self.parse_generics()?;
+
+ let decl = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| {
+ // This is somewhat dubious; We don't want to allow
+ // argument names to be left off if there is a
+ // definition...
+
+ // We don't allow argument names to be left off in edition 2018.
+ let is_name_required = p.token.span.rust_2018();
+ p.parse_arg_general(true, false, |_| is_name_required)
+ })?;
+ generics.where_clause = self.parse_where_clause()?;
+
+ let sig = ast::MethodSig {
+ header: FnHeader {
+ unsafety,
+ constness,
+ abi,
+ asyncness,
+ },
+ decl,
+ };
+
+ let body = match self.token.kind {
+ token::Semi => {
+ self.bump();
+ *at_end = true;
+ debug!("parse_trait_methods(): parsing required method");
+ None
+ }
+ token::OpenDelim(token::Brace) => {
+ debug!("parse_trait_methods(): parsing provided method");
+ *at_end = true;
+ let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(inner_attrs.iter().cloned());
+ Some(body)
+ }
+ token::Interpolated(ref nt) => {
+ match **nt {
+ token::NtBlock(..) => {
+ *at_end = true;
+ let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
+ attrs.extend(inner_attrs.iter().cloned());
+ Some(body)
+ }
+ _ => {
+ return self.expected_semi_or_open_brace();
+ }
+ }
+ }
+ _ => {
+ return self.expected_semi_or_open_brace();
+ }
+ };
+ (ident, ast::TraitItemKind::Method(sig, body), generics)
+ };
+
+ Ok(TraitItem {
+ id: ast::DUMMY_NODE_ID,
+ ident: name,
+ attrs,
+ generics,
+ node,
+ span: lo.to(self.prev_span),
+ tokens: None,
+ })
+ }
+
+ /// Parses the following grammar:
+ ///
+ /// TraitItemAssocTy = Ident ["<"...">"] [":" [GenericBounds]] ["where" ...] ["=" Ty]
+ fn parse_trait_item_assoc_ty(&mut self)
+ -> PResult<'a, (Ident, TraitItemKind, ast::Generics)> {
+ let ident = self.parse_ident()?;
+ let mut generics = self.parse_generics()?;
+
+ // Parse optional colon and param bounds.
+ let bounds = if self.eat(&token::Colon) {
+ self.parse_generic_bounds(None)?
+ } else {
+ Vec::new()
+ };
+ generics.where_clause = self.parse_where_clause()?;
+
+ let default = if self.eat(&token::Eq) {
+ Some(self.parse_ty()?)
+ } else {
+ None
+ };
+ self.expect(&token::Semi)?;
+
+ Ok((ident, TraitItemKind::Type(bounds, default), generics))
+ }
+
+ /// Parses a `UseTree`.
+ ///
+ /// ```
+ /// USE_TREE = [`::`] `*` |
+ /// [`::`] `{` USE_TREE_LIST `}` |
+ /// PATH `::` `*` |
+ /// PATH `::` `{` USE_TREE_LIST `}` |
+ /// PATH [`as` IDENT]
+ /// ```
+ fn parse_use_tree(&mut self) -> PResult<'a, UseTree> {
+ let lo = self.token.span;
+
+ let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo() };
+ let kind = if self.check(&token::OpenDelim(token::Brace)) ||
+ self.check(&token::BinOp(token::Star)) ||
+ self.is_import_coupler() {
+ // `use *;` or `use ::*;` or `use {...};` or `use ::{...};`
+ let mod_sep_ctxt = self.token.span.ctxt();
+ if self.eat(&token::ModSep) {
+ prefix.segments.push(
+ PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt))
+ );
+ }
+
+ if self.eat(&token::BinOp(token::Star)) {
+ UseTreeKind::Glob
+ } else {
+ UseTreeKind::Nested(self.parse_use_tree_list()?)
+ }
+ } else {
+ // `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;`
+ prefix = self.parse_path(PathStyle::Mod)?;
+
+ if self.eat(&token::ModSep) {
+ if self.eat(&token::BinOp(token::Star)) {
+ UseTreeKind::Glob
+ } else {
+ UseTreeKind::Nested(self.parse_use_tree_list()?)
+ }
+ } else {
+ UseTreeKind::Simple(self.parse_rename()?, ast::DUMMY_NODE_ID, ast::DUMMY_NODE_ID)
+ }
+ };
+
+ Ok(UseTree { prefix, kind, span: lo.to(self.prev_span) })
+ }
+
+ /// Parses a `UseTreeKind::Nested(list)`.
+ ///
+ /// ```
+ /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
+ /// ```
+ fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
+ self.parse_delim_comma_seq(token::Brace, |p| Ok((p.parse_use_tree()?, ast::DUMMY_NODE_ID)))
+ .map(|(r, _)| r)
+ }
+
+ fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
+ if self.eat_keyword(kw::As) {
+ self.parse_ident_or_underscore().map(Some)
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn parse_ident_or_underscore(&mut self) -> PResult<'a, ast::Ident> {
+ match self.token.kind {
+ token::Ident(name, false) if name == kw::Underscore => {
+ let span = self.token.span;
+ self.bump();
+ Ok(Ident::new(name, span))
+ }
+ _ => self.parse_ident(),
+ }
+ }
+
+ /// Parses `extern crate` links.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// extern crate foo;
+ /// extern crate bar as foo;
+ /// ```
+ fn parse_item_extern_crate(
+ &mut self,
+ lo: Span,
+ visibility: Visibility,
+ attrs: Vec<Attribute>
+ ) -> PResult<'a, P<Item>> {
+ // Accept `extern crate name-like-this` for better diagnostics
+ let orig_name = self.parse_crate_name_with_dashes()?;
+ let (item_name, orig_name) = if let Some(rename) = self.parse_rename()? {
+ (rename, Some(orig_name.name))
+ } else {
+ (orig_name, None)
+ };
+ self.expect(&token::Semi)?;
+
+ let span = lo.to(self.prev_span);
+ Ok(self.mk_item(span, item_name, ItemKind::ExternCrate(orig_name), visibility, attrs))
+ }
+
+ fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, ast::Ident> {
+ let error_msg = "crate name using dashes are not valid in `extern crate` statements";
+ let suggestion_msg = "if the original crate name uses dashes you need to use underscores \
+ in the code";
+ let mut ident = if self.token.is_keyword(kw::SelfLower) {
+ self.parse_path_segment_ident()
+ } else {
+ self.parse_ident()
+ }?;
+ let mut idents = vec![];
+ let mut replacement = vec![];
+ let mut fixed_crate_name = false;
+ // Accept `extern crate name-like-this` for better diagnostics
+ let dash = token::BinOp(token::BinOpToken::Minus);
+ if self.token == dash { // Do not include `-` as part of the expected tokens list
+ while self.eat(&dash) {
+ fixed_crate_name = true;
+ replacement.push((self.prev_span, "_".to_string()));
+ idents.push(self.parse_ident()?);
+ }
+ }
+ if fixed_crate_name {
+ let fixed_name_sp = ident.span.to(idents.last().unwrap().span);
+ let mut fixed_name = format!("{}", ident.name);
+ for part in idents {
+ fixed_name.push_str(&format!("_{}", part.name));
+ }
+ ident = Ident::from_str(&fixed_name).with_span_pos(fixed_name_sp);
+
+ self.struct_span_err(fixed_name_sp, error_msg)
+ .span_label(fixed_name_sp, "dash-separated idents are not valid")
+ .multipart_suggestion(suggestion_msg, replacement, Applicability::MachineApplicable)
+ .emit();
+ }
+ Ok(ident)
+ }
+
+ /// Parses an item-position function declaration.
+ fn parse_item_fn(
+ &mut self,
+ unsafety: Unsafety,
+ asyncness: Spanned<IsAsync>,
+ constness: Spanned<Constness>,
+ abi: Abi
+ ) -> PResult<'a, ItemInfo> {
+ let (ident, mut generics) = self.parse_fn_header()?;
+ let allow_c_variadic = abi == Abi::C && unsafety == Unsafety::Unsafe;
+ let decl = self.parse_fn_decl(allow_c_variadic)?;
+ generics.where_clause = self.parse_where_clause()?;
+ let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
+ let header = FnHeader { unsafety, asyncness, constness, abi };
+ Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs)))
+ }
+
+ /// Parses the name and optional generic types of a function header.
+ fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
+ let id = self.parse_ident()?;
+ let generics = self.parse_generics()?;
+ Ok((id, generics))
+ }
+
+ /// Parses the argument list and result type of a function declaration.
+ fn parse_fn_decl(&mut self, allow_c_variadic: bool) -> PResult<'a, P<FnDecl>> {
+ let (args, c_variadic) = self.parse_fn_args(true, allow_c_variadic)?;
+ let ret_ty = self.parse_ret_ty(true)?;
+
+ Ok(P(FnDecl {
+ inputs: args,
+ output: ret_ty,
+ c_variadic,
+ }))
+ }
+
+ /// Parses `extern` for foreign ABIs modules.
+ ///
+ /// `extern` is expected to have been
+ /// consumed before calling this method.
+ ///
+ /// # Examples
+ ///
+ /// ```ignore (only-for-syntax-highlight)
+ /// extern "C" {}
+ /// extern {}
+ /// ```
+ fn parse_item_foreign_mod(
+ &mut self,
+ lo: Span,
+ opt_abi: Option<Abi>,
+ visibility: Visibility,
+ mut attrs: Vec<Attribute>,
+ extern_sp: Span,
+ ) -> PResult<'a, P<Item>> {
+ self.expect(&token::OpenDelim(token::Brace))?;
+
+ let abi = opt_abi.unwrap_or(Abi::C);
+
+ attrs.extend(self.parse_inner_attributes()?);
+
+ let mut foreign_items = vec![];
+ while !self.eat(&token::CloseDelim(token::Brace)) {
+ foreign_items.push(self.parse_foreign_item(extern_sp)?);
+ }
+
+ let prev_span = self.prev_span;
+ let m = ast::ForeignMod {
+ abi,
+ items: foreign_items
+ };
+ let invalid = Ident::invalid();
+ Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs))
+ }
+
+ /// Parses a foreign item.
+ crate fn parse_foreign_item(&mut self, extern_sp: Span) -> PResult<'a, ForeignItem> {
+ maybe_whole!(self, NtForeignItem, |ni| ni);
+
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+ let visibility = self.parse_visibility(false)?;
+
+ // FOREIGN STATIC ITEM
+ // Treat `const` as `static` for error recovery, but don't add it to expected tokens.
+ if self.check_keyword(kw::Static) || self.token.is_keyword(kw::Const) {
+ if self.token.is_keyword(kw::Const) {
+ self.diagnostic()
+ .struct_span_err(self.token.span, "extern items cannot be `const`")
+ .span_suggestion(
+ self.token.span,
+ "try using a static value",
+ "static".to_owned(),
+ Applicability::MachineApplicable
+ ).emit();
+ }
+ self.bump(); // `static` or `const`
+ return Ok(self.parse_item_foreign_static(visibility, lo, attrs)?);
+ }
+ // FOREIGN FUNCTION ITEM
+ if self.check_keyword(kw::Fn) {
+ return Ok(self.parse_item_foreign_fn(visibility, lo, attrs, extern_sp)?);
+ }
+ // FOREIGN TYPE ITEM
+ if self.check_keyword(kw::Type) {
+ return Ok(self.parse_item_foreign_type(visibility, lo, attrs)?);
+ }
+
+ match self.parse_assoc_macro_invoc("extern", Some(&visibility), &mut false)? {
+ Some(mac) => {
+ Ok(
+ ForeignItem {
+ ident: Ident::invalid(),
+ span: lo.to(self.prev_span),
+ id: ast::DUMMY_NODE_ID,
+ attrs,
+ vis: visibility,
+ node: ForeignItemKind::Macro(mac),
+ }
+ )
+ }
+ None => {
+ if !attrs.is_empty() {
+ self.expected_item_err(&attrs)?;
+ }
+
+ self.unexpected()
+ }
+ }
+ }
+
+ /// Parses a function declaration from a foreign module.
+ fn parse_item_foreign_fn(
+ &mut self,
+ vis: ast::Visibility,
+ lo: Span,
+ attrs: Vec<Attribute>,
+ extern_sp: Span,
+ ) -> PResult<'a, ForeignItem> {
+ self.expect_keyword(kw::Fn)?;
+
+ let (ident, mut generics) = self.parse_fn_header()?;
+ let decl = self.parse_fn_decl(true)?;
+ generics.where_clause = self.parse_where_clause()?;
+ let hi = self.token.span;
+ self.parse_semi_or_incorrect_foreign_fn_body(&ident, extern_sp)?;
+ Ok(ast::ForeignItem {
+ ident,
+ attrs,
+ node: ForeignItemKind::Fn(decl, generics),
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(hi),
+ vis,
+ })
+ }
+
+ /// Parses a static item from a foreign module.
+ /// Assumes that the `static` keyword is already parsed.
+ fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
+ -> PResult<'a, ForeignItem> {
+ let mutbl = self.parse_mutability();
+ let ident = self.parse_ident()?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+ let hi = self.token.span;
+ self.expect(&token::Semi)?;
+ Ok(ForeignItem {
+ ident,
+ attrs,
+ node: ForeignItemKind::Static(ty, mutbl),
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(hi),
+ vis,
+ })
+ }
+
+ /// Parses a type from a foreign module.
+ fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
+ -> PResult<'a, ForeignItem> {
+ self.expect_keyword(kw::Type)?;
+
+ let ident = self.parse_ident()?;
+ let hi = self.token.span;
+ self.expect(&token::Semi)?;
+ Ok(ast::ForeignItem {
+ ident,
+ attrs,
+ node: ForeignItemKind::Ty,
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(hi),
+ vis
+ })
+ }
+
+ fn is_static_global(&mut self) -> bool {
+ if self.check_keyword(kw::Static) {
+ // Check if this could be a closure
+ !self.look_ahead(1, |token| {
+ if token.is_keyword(kw::Move) {
+ return true;
+ }
+ match token.kind {
+ token::BinOp(token::Or) | token::OrOr => true,
+ _ => false,
+ }
+ })
+ } else {
+ false
+ }
+ }
+
+ fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> {
+ let id = if m.is_none() { self.parse_ident_or_underscore() } else { self.parse_ident() }?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+ self.expect(&token::Eq)?;
+ let e = self.parse_expr()?;
+ self.expect(&token::Semi)?;
+ let item = match m {
+ Some(m) => ItemKind::Static(ty, m, e),
+ None => ItemKind::Const(ty, e),
+ };
+ Ok((id, item, None))
+ }
+
+ /// Parses `type Foo = Bar;` or returns `None`
+ /// without modifying the parser state.
+ fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> {
+ // This parses the grammar:
+ // Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";"
+ if self.eat_keyword(kw::Type) {
+ Some(self.parse_type_alias())
+ } else {
+ None
+ }
+ }
+
+ /// Parses a type alias or opaque type.
+ fn parse_type_alias(&mut self) -> PResult<'a, (Ident, AliasKind, ast::Generics)> {
+ let ident = self.parse_ident()?;
+ let mut tps = self.parse_generics()?;
+ tps.where_clause = self.parse_where_clause()?;
+ self.expect(&token::Eq)?;
+ let alias = if self.check_keyword(kw::Impl) {
+ self.bump();
+ let bounds = self.parse_generic_bounds(Some(self.prev_span))?;
+ AliasKind::OpaqueTy(bounds)
+ } else {
+ let ty = self.parse_ty()?;
+ AliasKind::Weak(ty)
+ };
+ self.expect(&token::Semi)?;
+ Ok((ident, alias, tps))
+ }
+
+ /// Parses an enum declaration.
+ fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
+ let id = self.parse_ident()?;
+ let mut generics = self.parse_generics()?;
+ generics.where_clause = self.parse_where_clause()?;
+ self.expect(&token::OpenDelim(token::Brace))?;
+
+ let enum_definition = self.parse_enum_def(&generics).map_err(|e| {
+ self.recover_stmt();
+ self.eat(&token::CloseDelim(token::Brace));
+ e
+ })?;
+ Ok((id, ItemKind::Enum(enum_definition, generics), None))
+ }
+
+ /// Parses the part of an enum declaration following the `{`.
+ fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
+ let mut variants = Vec::new();
+ while self.token != token::CloseDelim(token::Brace) {
+ let variant_attrs = self.parse_outer_attributes()?;
+ let vlo = self.token.span;
+
+ self.eat_bad_pub();
+ let ident = self.parse_ident()?;
+
+ let struct_def = if self.check(&token::OpenDelim(token::Brace)) {
+ // Parse a struct variant.
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else if self.check(&token::OpenDelim(token::Paren)) {
+ VariantData::Tuple(
+ self.parse_tuple_struct_body()?,
+ ast::DUMMY_NODE_ID,
+ )
+ } else {
+ VariantData::Unit(ast::DUMMY_NODE_ID)
+ };
+
+ let disr_expr = if self.eat(&token::Eq) {
+ Some(AnonConst {
+ id: ast::DUMMY_NODE_ID,
+ value: self.parse_expr()?,
+ })
+ } else {
+ None
+ };
+
+ let vr = ast::Variant_ {
+ ident,
+ id: ast::DUMMY_NODE_ID,
+ attrs: variant_attrs,
+ data: struct_def,
+ disr_expr,
+ };
+ variants.push(respan(vlo.to(self.prev_span), vr));
+
+ if !self.eat(&token::Comma) {
+ if self.token.is_ident() && !self.token.is_reserved_ident() {
+ let sp = self.sess.source_map().next_point(self.prev_span);
+ self.struct_span_err(sp, "missing comma")
+ .span_suggestion_short(
+ sp,
+ "missing comma",
+ ",".to_owned(),
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ } else {
+ break;
+ }
+ }
+ }
+ self.expect(&token::CloseDelim(token::Brace))?;
+
+ Ok(ast::EnumDef { variants })
+ }
+
+ /// Parses `struct Foo { ... }`.
+ fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
+ let class_name = self.parse_ident()?;
+
+ let mut generics = self.parse_generics()?;
+
+ // There is a special case worth noting here, as reported in issue #17904.
+ // If we are parsing a tuple struct it is the case that the where clause
+ // should follow the field list. Like so:
+ //
+ // struct Foo<T>(T) where T: Copy;
+ //
+ // If we are parsing a normal record-style struct it is the case
+ // that the where clause comes before the body, and after the generics.
+ // So if we look ahead and see a brace or a where-clause we begin
+ // parsing a record style struct.
+ //
+ // Otherwise if we look ahead and see a paren we parse a tuple-style
+ // struct.
+
+ let vdata = if self.token.is_keyword(kw::Where) {
+ generics.where_clause = self.parse_where_clause()?;
+ if self.eat(&token::Semi) {
+ // If we see a: `struct Foo<T> where T: Copy;` style decl.
+ VariantData::Unit(ast::DUMMY_NODE_ID)
+ } else {
+ // If we see: `struct Foo<T> where T: Copy { ... }`
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ }
+ // No `where` so: `struct Foo<T>;`
+ } else if self.eat(&token::Semi) {
+ VariantData::Unit(ast::DUMMY_NODE_ID)
+ // Record-style struct definition
+ } else if self.token == token::OpenDelim(token::Brace) {
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ // Tuple-style struct definition with optional where-clause.
+ } else if self.token == token::OpenDelim(token::Paren) {
+ let body = VariantData::Tuple(self.parse_tuple_struct_body()?, ast::DUMMY_NODE_ID);
+ generics.where_clause = self.parse_where_clause()?;
+ self.expect(&token::Semi)?;
+ body
+ } else {
+ let token_str = self.this_token_descr();
+ let mut err = self.fatal(&format!(
+ "expected `where`, `{{`, `(`, or `;` after struct name, found {}",
+ token_str
+ ));
+ err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name");
+ return Err(err);
+ };
+
+ Ok((class_name, ItemKind::Struct(vdata, generics), None))
+ }
+
+ /// Parses `union Foo { ... }`.
+ fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> {
+ let class_name = self.parse_ident()?;
+
+ let mut generics = self.parse_generics()?;
+
+ let vdata = if self.token.is_keyword(kw::Where) {
+ generics.where_clause = self.parse_where_clause()?;
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else if self.token == token::OpenDelim(token::Brace) {
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else {
+ let token_str = self.this_token_descr();
+ let mut err = self.fatal(&format!(
+ "expected `where` or `{{` after union name, found {}", token_str));
+ err.span_label(self.token.span, "expected `where` or `{` after union name");
+ return Err(err);
+ };
+
+ Ok((class_name, ItemKind::Union(vdata, generics), None))
+ }
+
+ pub(super) fn is_union_item(&self) -> bool {
+ self.token.is_keyword(kw::Union) &&
+ self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
+ }
+
+ fn parse_record_struct_body(
+ &mut self,
+ ) -> PResult<'a, (Vec<StructField>, /* recovered */ bool)> {
+ let mut fields = Vec::new();
+ let mut recovered = false;
+ if self.eat(&token::OpenDelim(token::Brace)) {
+ while self.token != token::CloseDelim(token::Brace) {
+ let field = self.parse_struct_decl_field().map_err(|e| {
+ self.recover_stmt();
+ recovered = true;
+ e
+ });
+ match field {
+ Ok(field) => fields.push(field),
+ Err(mut err) => {
+ err.emit();
+ }
+ }
+ }
+ self.eat(&token::CloseDelim(token::Brace));
+ } else {
+ let token_str = self.this_token_descr();
+ let mut err = self.fatal(&format!(
+ "expected `where`, or `{{` after struct name, found {}", token_str));
+ err.span_label(self.token.span, "expected `where`, or `{` after struct name");
+ return Err(err);
+ }
+
+ Ok((fields, recovered))
+ }
+
+ fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
+ // This is the case where we find `struct Foo<T>(T) where T: Copy;`
+ // Unit like structs are handled in parse_item_struct function
+ self.parse_paren_comma_seq(|p| {
+ let attrs = p.parse_outer_attributes()?;
+ let lo = p.token.span;
+ let vis = p.parse_visibility(true)?;
+ let ty = p.parse_ty()?;
+ Ok(StructField {
+ span: lo.to(ty.span),
+ vis,
+ ident: None,
+ id: ast::DUMMY_NODE_ID,
+ ty,
+ attrs,
+ })
+ }).map(|(r, _)| r)
+ }
+
+ /// Parses an element of a struct declaration.
+ fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+ let vis = self.parse_visibility(false)?;
+ self.parse_single_struct_field(lo, vis, attrs)
+ }
+
+ /// Parses a structure field declaration.
+ fn parse_single_struct_field(&mut self,
+ lo: Span,
+ vis: Visibility,
+ attrs: Vec<Attribute> )
+ -> PResult<'a, StructField> {
+ let mut seen_comma: bool = false;
+ let a_var = self.parse_name_and_ty(lo, vis, attrs)?;
+ if self.token == token::Comma {
+ seen_comma = true;
+ }
+ match self.token.kind {
+ token::Comma => {
+ self.bump();
+ }
+ token::CloseDelim(token::Brace) => {}
+ token::DocComment(_) => {
+ let previous_span = self.prev_span;
+ let mut err = self.span_fatal_err(self.token.span, Error::UselessDocComment);
+ self.bump(); // consume the doc comment
+ let comma_after_doc_seen = self.eat(&token::Comma);
+ // `seen_comma` is always false, because we are inside doc block
+ // condition is here to make code more readable
+ if seen_comma == false && comma_after_doc_seen == true {
+ seen_comma = true;
+ }
+ if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) {
+ err.emit();
+ } else {
+ if seen_comma == false {
+ let sp = self.sess.source_map().next_point(previous_span);
+ err.span_suggestion(
+ sp,
+ "missing comma here",
+ ",".into(),
+ Applicability::MachineApplicable
+ );
+ }
+ return Err(err);
+ }
+ }
+ _ => {
+ let sp = self.sess.source_map().next_point(self.prev_span);
+ let mut err = self.struct_span_err(sp, &format!("expected `,`, or `}}`, found {}",
+ self.this_token_descr()));
+ if self.token.is_ident() {
+ // This is likely another field; emit the diagnostic and keep going
+ err.span_suggestion(
+ sp,
+ "try adding a comma",
+ ",".into(),
+ Applicability::MachineApplicable,
+ );
+ err.emit();
+ } else {
+ return Err(err)
+ }
+ }
+ }
+ Ok(a_var)
+ }
+
+ /// Parses a structure field.
+ fn parse_name_and_ty(
+ &mut self,
+ lo: Span,
+ vis: Visibility,
+ attrs: Vec<Attribute>
+ ) -> PResult<'a, StructField> {
+ let name = self.parse_ident()?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+ Ok(StructField {
+ span: lo.to(self.prev_span),
+ ident: Some(name),
+ vis,
+ id: ast::DUMMY_NODE_ID,
+ ty,
+ attrs,
+ })
+ }
+
+ pub(super) fn eat_macro_def(
+ &mut self,
+ attrs: &[Attribute],
+ vis: &Visibility,
+ lo: Span
+ ) -> PResult<'a, Option<P<Item>>> {
+ let token_lo = self.token.span;
+ let (ident, def) = if self.eat_keyword(kw::Macro) {
+ let ident = self.parse_ident()?;
+ let tokens = if self.check(&token::OpenDelim(token::Brace)) {
+ match self.parse_token_tree() {
+ TokenTree::Delimited(_, _, tts) => tts,
+ _ => unreachable!(),
+ }
+ } else if self.check(&token::OpenDelim(token::Paren)) {
+ let args = self.parse_token_tree();
+ let body = if self.check(&token::OpenDelim(token::Brace)) {
+ self.parse_token_tree()
+ } else {
+ self.unexpected()?;
+ unreachable!()
+ };
+ TokenStream::new(vec![
+ args.into(),
+ TokenTree::token(token::FatArrow, token_lo.to(self.prev_span)).into(),
+ body.into(),
+ ])
+ } else {
+ self.unexpected()?;
+ unreachable!()
+ };
+
+ (ident, ast::MacroDef { tokens: tokens.into(), legacy: false })
+ } else if self.check_keyword(sym::macro_rules) &&
+ self.look_ahead(1, |t| *t == token::Not) &&
+ self.look_ahead(2, |t| t.is_ident()) {
+ let prev_span = self.prev_span;
+ self.complain_if_pub_macro(&vis.node, prev_span);
+ self.bump();
+ self.bump();
+
+ let ident = self.parse_ident()?;
+ let (delim, tokens) = self.expect_delimited_token_tree()?;
+ if delim != MacDelimiter::Brace && !self.eat(&token::Semi) {
+ self.report_invalid_macro_expansion_item();
+ }
+
+ (ident, ast::MacroDef { tokens, legacy: true })
+ } else {
+ return Ok(None);
+ };
+
+ let span = lo.to(self.prev_span);
+ Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec())))
+ }
+
+ fn complain_if_pub_macro(&self, vis: &VisibilityKind, sp: Span) {
+ match *vis {
+ VisibilityKind::Inherited => {}
+ _ => {
+ let mut err = if self.token.is_keyword(sym::macro_rules) {
+ let mut err = self.diagnostic()
+ .struct_span_err(sp, "can't qualify macro_rules invocation with `pub`");
+ err.span_suggestion(
+ sp,
+ "try exporting the macro",
+ "#[macro_export]".to_owned(),
+ Applicability::MaybeIncorrect // speculative
+ );
+ err
+ } else {
+ let mut err = self.diagnostic()
+ .struct_span_err(sp, "can't qualify macro invocation with `pub`");
+ err.help("try adjusting the macro to put `pub` inside the invocation");
+ err
+ };
+ err.emit();
+ }
+ }
+ }
+
+ fn mk_item(&self, span: Span, ident: Ident, node: ItemKind, vis: Visibility,
+ attrs: Vec<Attribute>) -> P<Item> {
+ P(Item {
+ ident,
+ attrs,
+ id: ast::DUMMY_NODE_ID,
+ node,
+ vis,
+ span,
+ tokens: None,
+ })
+ }
+}
--- /dev/null
+use super::{Parser, PResult};
+use super::item::ItemInfo;
+
+use crate::attr;
+use crate::ast::{self, Ident, Attribute, ItemKind, Mod, Crate};
+use crate::parse::{new_sub_parser_from_file, DirectoryOwnership};
+use crate::parse::token::{self, TokenKind};
+use crate::parse::diagnostics::{Error};
+use crate::source_map::{SourceMap, Span, DUMMY_SP, FileName};
+use crate::symbol::sym;
+
+use std::path::{self, Path, PathBuf};
+
+/// Information about the path to a module.
+pub struct ModulePath {
+ name: String,
+ path_exists: bool,
+ pub result: Result<ModulePathSuccess, Error>,
+}
+
+pub struct ModulePathSuccess {
+ pub path: PathBuf,
+ pub directory_ownership: DirectoryOwnership,
+ warn: bool,
+}
+
+impl<'a> Parser<'a> {
+ /// Parses a source module as a crate. This is the main entry point for the parser.
+ pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
+ let lo = self.token.span;
+ let krate = Ok(ast::Crate {
+ attrs: self.parse_inner_attributes()?,
+ module: self.parse_mod_items(&token::Eof, lo)?,
+ span: lo.to(self.token.span),
+ });
+ krate
+ }
+
+ /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
+ pub(super) fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
+ let (in_cfg, outer_attrs) = {
+ let mut strip_unconfigured = crate::config::StripUnconfigured {
+ sess: self.sess,
+ features: None, // don't perform gated feature checking
+ };
+ let mut outer_attrs = outer_attrs.to_owned();
+ strip_unconfigured.process_cfg_attrs(&mut outer_attrs);
+ (!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs)
+ };
+
+ let id_span = self.token.span;
+ let id = self.parse_ident()?;
+ if self.eat(&token::Semi) {
+ if in_cfg && self.recurse_into_file_modules {
+ // This mod is in an external file. Let's go get it!
+ let ModulePathSuccess { path, directory_ownership, warn } =
+ self.submod_path(id, &outer_attrs, id_span)?;
+ let (module, mut attrs) =
+ self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
+ // Record that we fetched the mod from an external file
+ if warn {
+ let attr = attr::mk_attr_outer(
+ attr::mk_word_item(Ident::with_empty_ctxt(sym::warn_directory_ownership)));
+ attr::mark_known(&attr);
+ attrs.push(attr);
+ }
+ Ok((id, ItemKind::Mod(module), Some(attrs)))
+ } else {
+ let placeholder = ast::Mod {
+ inner: DUMMY_SP,
+ items: Vec::new(),
+ inline: false
+ };
+ Ok((id, ItemKind::Mod(placeholder), None))
+ }
+ } else {
+ let old_directory = self.directory.clone();
+ self.push_directory(id, &outer_attrs);
+
+ self.expect(&token::OpenDelim(token::Brace))?;
+ let mod_inner_lo = self.token.span;
+ let attrs = self.parse_inner_attributes()?;
+ let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
+
+ self.directory = old_directory;
+ Ok((id, ItemKind::Mod(module), Some(attrs)))
+ }
+ }
+
+ /// Given a termination token, parses all of the items in a module.
+ fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> {
+ let mut items = vec![];
+ while let Some(item) = self.parse_item()? {
+ items.push(item);
+ self.maybe_consume_incorrect_semicolon(&items);
+ }
+
+ if !self.eat(term) {
+ let token_str = self.this_token_descr();
+ if !self.maybe_consume_incorrect_semicolon(&items) {
+ let mut err = self.fatal(&format!("expected item, found {}", token_str));
+ err.span_label(self.token.span, "expected item");
+ return Err(err);
+ }
+ }
+
+ let hi = if self.token.span.is_dummy() {
+ inner_lo
+ } else {
+ self.prev_span
+ };
+
+ Ok(Mod {
+ inner: inner_lo.to(hi),
+ items,
+ inline: true
+ })
+ }
+
+ fn submod_path(
+ &mut self,
+ id: ast::Ident,
+ outer_attrs: &[Attribute],
+ id_sp: Span
+ ) -> PResult<'a, ModulePathSuccess> {
+ if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
+ return Ok(ModulePathSuccess {
+ directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
+ // All `#[path]` files are treated as though they are a `mod.rs` file.
+ // This means that `mod foo;` declarations inside `#[path]`-included
+ // files are siblings,
+ //
+ // Note that this will produce weirdness when a file named `foo.rs` is
+ // `#[path]` included and contains a `mod foo;` declaration.
+ // If you encounter this, it's your own darn fault :P
+ Some(_) => DirectoryOwnership::Owned { relative: None },
+ _ => DirectoryOwnership::UnownedViaMod(true),
+ },
+ path,
+ warn: false,
+ });
+ }
+
+ let relative = match self.directory.ownership {
+ DirectoryOwnership::Owned { relative } => relative,
+ DirectoryOwnership::UnownedViaBlock |
+ DirectoryOwnership::UnownedViaMod(_) => None,
+ };
+ let paths = Parser::default_submod_path(
+ id, relative, &self.directory.path, self.sess.source_map());
+
+ match self.directory.ownership {
+ DirectoryOwnership::Owned { .. } => {
+ paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
+ },
+ DirectoryOwnership::UnownedViaBlock => {
+ let msg =
+ "Cannot declare a non-inline module inside a block \
+ unless it has a path attribute";
+ let mut err = self.diagnostic().struct_span_err(id_sp, msg);
+ if paths.path_exists {
+ let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
+ paths.name);
+ err.span_note(id_sp, &msg);
+ }
+ Err(err)
+ }
+ DirectoryOwnership::UnownedViaMod(warn) => {
+ if warn {
+ if let Ok(result) = paths.result {
+ return Ok(ModulePathSuccess { warn: true, ..result });
+ }
+ }
+ let mut err = self.diagnostic().struct_span_err(id_sp,
+ "cannot declare a new module at this location");
+ if !id_sp.is_dummy() {
+ let src_path = self.sess.source_map().span_to_filename(id_sp);
+ if let FileName::Real(src_path) = src_path {
+ if let Some(stem) = src_path.file_stem() {
+ let mut dest_path = src_path.clone();
+ dest_path.set_file_name(stem);
+ dest_path.push("mod.rs");
+ err.span_note(id_sp,
+ &format!("maybe move this module `{}` to its own \
+ directory via `{}`", src_path.display(),
+ dest_path.display()));
+ }
+ }
+ }
+ if paths.path_exists {
+ err.span_note(id_sp,
+ &format!("... or maybe `use` the module `{}` instead \
+ of possibly redeclaring it",
+ paths.name));
+ }
+ Err(err)
+ }
+ }
+ }
+
+ pub fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
+ if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
+ let s = s.as_str();
+
+ // On windows, the base path might have the form
+ // `\\?\foo\bar` in which case it does not tolerate
+ // mixed `/` and `\` separators, so canonicalize
+ // `/` to `\`.
+ #[cfg(windows)]
+ let s = s.replace("/", "\\");
+ Some(dir_path.join(s))
+ } else {
+ None
+ }
+ }
+
+ /// Returns a path to a module.
+ pub fn default_submod_path(
+ id: ast::Ident,
+ relative: Option<ast::Ident>,
+ dir_path: &Path,
+ source_map: &SourceMap) -> ModulePath
+ {
+ // If we're in a foo.rs file instead of a mod.rs file,
+ // we need to look for submodules in
+ // `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
+ // `./<id>.rs` and `./<id>/mod.rs`.
+ let relative_prefix_string;
+ let relative_prefix = if let Some(ident) = relative {
+ relative_prefix_string = format!("{}{}", ident.as_str(), path::MAIN_SEPARATOR);
+ &relative_prefix_string
+ } else {
+ ""
+ };
+
+ let mod_name = id.to_string();
+ let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
+ let secondary_path_str = format!("{}{}{}mod.rs",
+ relative_prefix, mod_name, path::MAIN_SEPARATOR);
+ let default_path = dir_path.join(&default_path_str);
+ let secondary_path = dir_path.join(&secondary_path_str);
+ let default_exists = source_map.file_exists(&default_path);
+ let secondary_exists = source_map.file_exists(&secondary_path);
+
+ let result = match (default_exists, secondary_exists) {
+ (true, false) => Ok(ModulePathSuccess {
+ path: default_path,
+ directory_ownership: DirectoryOwnership::Owned {
+ relative: Some(id),
+ },
+ warn: false,
+ }),
+ (false, true) => Ok(ModulePathSuccess {
+ path: secondary_path,
+ directory_ownership: DirectoryOwnership::Owned {
+ relative: None,
+ },
+ warn: false,
+ }),
+ (false, false) => Err(Error::FileNotFoundForModule {
+ mod_name: mod_name.clone(),
+ default_path: default_path_str,
+ secondary_path: secondary_path_str,
+ dir_path: dir_path.display().to_string(),
+ }),
+ (true, true) => Err(Error::DuplicatePaths {
+ mod_name: mod_name.clone(),
+ default_path: default_path_str,
+ secondary_path: secondary_path_str,
+ }),
+ };
+
+ ModulePath {
+ name: mod_name,
+ path_exists: default_exists || secondary_exists,
+ result,
+ }
+ }
+
+ /// Reads a module from a source file.
+ fn eval_src_mod(
+ &mut self,
+ path: PathBuf,
+ directory_ownership: DirectoryOwnership,
+ name: String,
+ id_sp: Span,
+ ) -> PResult<'a, (Mod, Vec<Attribute>)> {
+ let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
+ if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
+ let mut err = String::from("circular modules: ");
+ let len = included_mod_stack.len();
+ for p in &included_mod_stack[i.. len] {
+ err.push_str(&p.to_string_lossy());
+ err.push_str(" -> ");
+ }
+ err.push_str(&path.to_string_lossy());
+ return Err(self.span_fatal(id_sp, &err[..]));
+ }
+ included_mod_stack.push(path.clone());
+ drop(included_mod_stack);
+
+ let mut p0 =
+ new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
+ p0.cfg_mods = self.cfg_mods;
+ let mod_inner_lo = p0.token.span;
+ let mod_attrs = p0.parse_inner_attributes()?;
+ let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
+ m0.inline = false;
+ self.sess.included_mod_stack.borrow_mut().pop();
+ Ok((m0, mod_attrs))
+ }
+
+ fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
+ if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
+ self.directory.path.to_mut().push(&path.as_str());
+ self.directory.ownership = DirectoryOwnership::Owned { relative: None };
+ } else {
+ // We have to push on the current module name in the case of relative
+ // paths in order to ensure that any additional module paths from inline
+ // `mod x { ... }` come after the relative extension.
+ //
+ // For example, a `mod z { ... }` inside `x/y.rs` should set the current
+ // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
+ if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
+ if let Some(ident) = relative.take() { // remove the relative offset
+ self.directory.path.to_mut().push(ident.as_str());
+ }
+ }
+ self.directory.path.to_mut().push(&id.as_str());
+ }
+ }
+}
--- /dev/null
+use super::{Parser, PResult, PathStyle};
+
+use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
+use crate::ptr::P;
+use crate::ast::{self, Attribute, Pat, PatKind, FieldPat, RangeEnd, RangeSyntax, Mac_};
+use crate::ast::{BindingMode, Ident, Mutability, Expr, ExprKind};
+use crate::parse::token::{self};
+use crate::print::pprust;
+use crate::source_map::{respan, Span, Spanned};
+use crate::symbol::kw;
+use crate::ThinVec;
+
+use errors::{Applicability, DiagnosticBuilder};
+
+impl<'a> Parser<'a> {
+ /// Parses a pattern.
+ pub fn parse_pat(&mut self, expected: Option<&'static str>) -> PResult<'a, P<Pat>> {
+ self.parse_pat_with_range_pat(true, expected)
+ }
+
+ /// Parses patterns, separated by '|' s.
+ pub(super) fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
+ // Allow a '|' before the pats (RFC 1925 + RFC 2530)
+ self.eat(&token::BinOp(token::Or));
+
+ let mut pats = Vec::new();
+ loop {
+ pats.push(self.parse_top_level_pat()?);
+
+ if self.token == token::OrOr {
+ self.struct_span_err(self.token.span, "unexpected token `||` after pattern")
+ .span_suggestion(
+ self.token.span,
+ "use a single `|` to specify multiple patterns",
+ "|".to_owned(),
+ Applicability::MachineApplicable
+ )
+ .emit();
+ self.bump();
+ } else if self.eat(&token::BinOp(token::Or)) {
+ // This is a No-op. Continue the loop to parse the next
+ // pattern.
+ } else {
+ return Ok(pats);
+ }
+ };
+ }
+
+ /// A wrapper around `parse_pat` with some special error handling for the
+ /// "top-level" patterns in a match arm, `for` loop, `let`, &c. (in contrast
+ /// to subpatterns within such).
+ pub(super) fn parse_top_level_pat(&mut self) -> PResult<'a, P<Pat>> {
+ let pat = self.parse_pat(None)?;
+ if self.token == token::Comma {
+ // An unexpected comma after a top-level pattern is a clue that the
+ // user (perhaps more accustomed to some other language) forgot the
+ // parentheses in what should have been a tuple pattern; return a
+ // suggestion-enhanced error here rather than choking on the comma
+ // later.
+ let comma_span = self.token.span;
+ self.bump();
+ if let Err(mut err) = self.skip_pat_list() {
+ // We didn't expect this to work anyway; we just wanted
+ // to advance to the end of the comma-sequence so we know
+ // the span to suggest parenthesizing
+ err.cancel();
+ }
+ let seq_span = pat.span.to(self.prev_span);
+ let mut err = self.struct_span_err(comma_span, "unexpected `,` in pattern");
+ if let Ok(seq_snippet) = self.span_to_snippet(seq_span) {
+ err.span_suggestion(
+ seq_span,
+ "try adding parentheses to match on a tuple..",
+ format!("({})", seq_snippet),
+ Applicability::MachineApplicable
+ ).span_suggestion(
+ seq_span,
+ "..or a vertical bar to match on multiple alternatives",
+ format!("{}", seq_snippet.replace(",", " |")),
+ Applicability::MachineApplicable
+ );
+ }
+ return Err(err);
+ }
+ Ok(pat)
+ }
+
+ /// Parse and throw away a parentesized comma separated
+ /// sequence of patterns until `)` is reached.
+ fn skip_pat_list(&mut self) -> PResult<'a, ()> {
+ while !self.check(&token::CloseDelim(token::Paren)) {
+ self.parse_pat(None)?;
+ if !self.eat(&token::Comma) {
+ return Ok(())
+ }
+ }
+ Ok(())
+ }
+
+ /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are
+ /// allowed).
+ fn parse_pat_with_range_pat(
+ &mut self,
+ allow_range_pat: bool,
+ expected: Option<&'static str>,
+ ) -> PResult<'a, P<Pat>> {
+ maybe_recover_from_interpolated_ty_qpath!(self, true);
+ maybe_whole!(self, NtPat, |x| x);
+
+ let lo = self.token.span;
+ let pat;
+ match self.token.kind {
+ token::BinOp(token::And) | token::AndAnd => {
+ // Parse &pat / &mut pat
+ self.expect_and()?;
+ let mutbl = self.parse_mutability();
+ if let token::Lifetime(name) = self.token.kind {
+ let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name));
+ err.span_label(self.token.span, "unexpected lifetime");
+ return Err(err);
+ }
+ let subpat = self.parse_pat_with_range_pat(false, expected)?;
+ pat = PatKind::Ref(subpat, mutbl);
+ }
+ token::OpenDelim(token::Paren) => {
+ // Parse a tuple or parenthesis pattern.
+ let (fields, trailing_comma) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
+
+ // Here, `(pat,)` is a tuple pattern.
+ // For backward compatibility, `(..)` is a tuple pattern as well.
+ pat = if fields.len() == 1 && !(trailing_comma || fields[0].is_rest()) {
+ PatKind::Paren(fields.into_iter().nth(0).unwrap())
+ } else {
+ PatKind::Tuple(fields)
+ };
+ }
+ token::OpenDelim(token::Bracket) => {
+ // Parse `[pat, pat,...]` as a slice pattern.
+ let (slice, _) = self.parse_delim_comma_seq(token::Bracket, |p| p.parse_pat(None))?;
+ pat = PatKind::Slice(slice);
+ }
+ token::DotDot => {
+ self.bump();
+ pat = if self.is_pat_range_end_start() {
+ // Parse `..42` for recovery.
+ self.parse_pat_range_to(RangeEnd::Excluded, "..")?
+ } else {
+ // A rest pattern `..`.
+ PatKind::Rest
+ };
+ }
+ token::DotDotEq => {
+ // Parse `..=42` for recovery.
+ self.bump();
+ pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotEq), "..=")?;
+ }
+ token::DotDotDot => {
+ // Parse `...42` for recovery.
+ self.bump();
+ pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotDot), "...")?;
+ }
+ // At this point, token != &, &&, (, [
+ _ => if self.eat_keyword(kw::Underscore) {
+ // Parse _
+ pat = PatKind::Wild;
+ } else if self.eat_keyword(kw::Mut) {
+ // Parse mut ident @ pat / mut ref ident @ pat
+ let mutref_span = self.prev_span.to(self.token.span);
+ let binding_mode = if self.eat_keyword(kw::Ref) {
+ self.diagnostic()
+ .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
+ .span_suggestion(
+ mutref_span,
+ "try switching the order",
+ "ref mut".into(),
+ Applicability::MachineApplicable
+ ).emit();
+ BindingMode::ByRef(Mutability::Mutable)
+ } else {
+ BindingMode::ByValue(Mutability::Mutable)
+ };
+ pat = self.parse_pat_ident(binding_mode)?;
+ } else if self.eat_keyword(kw::Ref) {
+ // Parse ref ident @ pat / ref mut ident @ pat
+ let mutbl = self.parse_mutability();
+ pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?;
+ } else if self.eat_keyword(kw::Box) {
+ // Parse box pat
+ let subpat = self.parse_pat_with_range_pat(false, None)?;
+ pat = PatKind::Box(subpat);
+ } else if self.token.is_ident() && !self.token.is_reserved_ident() &&
+ self.parse_as_ident() {
+ // Parse ident @ pat
+ // This can give false positives and parse nullary enums,
+ // they are dealt with later in resolve
+ let binding_mode = BindingMode::ByValue(Mutability::Immutable);
+ pat = self.parse_pat_ident(binding_mode)?;
+ } else if self.token.is_path_start() {
+ // Parse pattern starting with a path
+ let (qself, path) = if self.eat_lt() {
+ // Parse a qualified path
+ let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
+ (Some(qself), path)
+ } else {
+ // Parse an unqualified path
+ (None, self.parse_path(PathStyle::Expr)?)
+ };
+ match self.token.kind {
+ token::Not if qself.is_none() => {
+ // Parse macro invocation
+ self.bump();
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ let mac = respan(lo.to(self.prev_span), Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ });
+ pat = PatKind::Mac(mac);
+ }
+ token::DotDotDot | token::DotDotEq | token::DotDot => {
+ let (end_kind, form) = match self.token.kind {
+ token::DotDot => (RangeEnd::Excluded, ".."),
+ token::DotDotDot => (RangeEnd::Included(RangeSyntax::DotDotDot), "..."),
+ token::DotDotEq => (RangeEnd::Included(RangeSyntax::DotDotEq), "..="),
+ _ => panic!("can only parse `..`/`...`/`..=` for ranges \
+ (checked above)"),
+ };
+ let op_span = self.token.span;
+ // Parse range
+ let span = lo.to(self.prev_span);
+ let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new());
+ self.bump();
+ let end = self.parse_pat_range_end_opt(&begin, form)?;
+ pat = PatKind::Range(begin, end, respan(op_span, end_kind));
+ }
+ token::OpenDelim(token::Brace) => {
+ if qself.is_some() {
+ let msg = "unexpected `{` after qualified path";
+ let mut err = self.fatal(msg);
+ err.span_label(self.token.span, msg);
+ return Err(err);
+ }
+ // Parse struct pattern
+ self.bump();
+ let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
+ e.emit();
+ self.recover_stmt();
+ (vec![], true)
+ });
+ self.bump();
+ pat = PatKind::Struct(path, fields, etc);
+ }
+ token::OpenDelim(token::Paren) => {
+ if qself.is_some() {
+ let msg = "unexpected `(` after qualified path";
+ let mut err = self.fatal(msg);
+ err.span_label(self.token.span, msg);
+ return Err(err);
+ }
+ // Parse tuple struct or enum pattern
+ let (fields, _) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?;
+ pat = PatKind::TupleStruct(path, fields)
+ }
+ _ => pat = PatKind::Path(qself, path),
+ }
+ } else {
+ // Try to parse everything else as literal with optional minus
+ match self.parse_literal_maybe_minus() {
+ Ok(begin) => {
+ let op_span = self.token.span;
+ if self.check(&token::DotDot) || self.check(&token::DotDotEq) ||
+ self.check(&token::DotDotDot) {
+ let (end_kind, form) = if self.eat(&token::DotDotDot) {
+ (RangeEnd::Included(RangeSyntax::DotDotDot), "...")
+ } else if self.eat(&token::DotDotEq) {
+ (RangeEnd::Included(RangeSyntax::DotDotEq), "..=")
+ } else if self.eat(&token::DotDot) {
+ (RangeEnd::Excluded, "..")
+ } else {
+ panic!("impossible case: we already matched \
+ on a range-operator token")
+ };
+ let end = self.parse_pat_range_end_opt(&begin, form)?;
+ pat = PatKind::Range(begin, end, respan(op_span, end_kind))
+ } else {
+ pat = PatKind::Lit(begin);
+ }
+ }
+ Err(mut err) => {
+ self.cancel(&mut err);
+ let expected = expected.unwrap_or("pattern");
+ let msg = format!(
+ "expected {}, found {}",
+ expected,
+ self.this_token_descr(),
+ );
+ let mut err = self.fatal(&msg);
+ err.span_label(self.token.span, format!("expected {}", expected));
+ let sp = self.sess.source_map().start_point(self.token.span);
+ if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) {
+ self.sess.expr_parentheses_needed(&mut err, *sp, None);
+ }
+ return Err(err);
+ }
+ }
+ }
+ }
+
+ let pat = self.mk_pat(lo.to(self.prev_span), pat);
+ let pat = self.maybe_recover_from_bad_qpath(pat, true)?;
+
+ if !allow_range_pat {
+ match pat.node {
+ PatKind::Range(
+ _, _, Spanned { node: RangeEnd::Included(RangeSyntax::DotDotDot), .. }
+ ) => {},
+ PatKind::Range(..) => {
+ let mut err = self.struct_span_err(
+ pat.span,
+ "the range pattern here has ambiguous interpretation",
+ );
+ err.span_suggestion(
+ pat.span,
+ "add parentheses to clarify the precedence",
+ format!("({})", pprust::pat_to_string(&pat)),
+ // "ambiguous interpretation" implies that we have to be guessing
+ Applicability::MaybeIncorrect
+ );
+ return Err(err);
+ }
+ _ => {}
+ }
+ }
+
+ Ok(pat)
+ }
+
+ // Helper function to decide whether to parse as ident binding
+ // or to try to do something more complex like range patterns.
+ fn parse_as_ident(&mut self) -> bool {
+ self.look_ahead(1, |t| match t.kind {
+ token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) |
+ token::DotDotDot | token::DotDotEq | token::DotDot |
+ token::ModSep | token::Not => false,
+ _ => true,
+ })
+ }
+
+ /// Is the current token suitable as the start of a range patterns end?
+ fn is_pat_range_end_start(&self) -> bool {
+ self.token.is_path_start() // e.g. `MY_CONST`;
+ || self.token == token::Dot // e.g. `.5` for recovery;
+ || self.token.can_begin_literal_or_bool() // e.g. `42`.
+ || self.token.is_whole_expr()
+ }
+
+ /// Parse a range-to pattern, e.g. `..X` and `..=X` for recovery.
+ fn parse_pat_range_to(&mut self, re: RangeEnd, form: &str) -> PResult<'a, PatKind> {
+ let lo = self.prev_span;
+ let end = self.parse_pat_range_end()?;
+ let range_span = lo.to(end.span);
+ let begin = self.mk_expr(range_span, ExprKind::Err, ThinVec::new());
+
+ self.diagnostic()
+ .struct_span_err(range_span, &format!("`{}X` range patterns are not supported", form))
+ .span_suggestion(
+ range_span,
+ "try using the minimum value for the type",
+ format!("MIN{}{}", form, pprust::expr_to_string(&end)),
+ Applicability::HasPlaceholders,
+ )
+ .emit();
+
+ Ok(PatKind::Range(begin, end, respan(lo, re)))
+ }
+
+ /// Parse the end of a `X..Y`, `X..=Y`, or `X...Y` range pattern or recover
+ /// if that end is missing treating it as `X..`, `X..=`, or `X...` respectively.
+ fn parse_pat_range_end_opt(&mut self, begin: &Expr, form: &str) -> PResult<'a, P<Expr>> {
+ if self.is_pat_range_end_start() {
+ // Parsing e.g. `X..=Y`.
+ self.parse_pat_range_end()
+ } else {
+ // Parsing e.g. `X..`.
+ let range_span = begin.span.to(self.prev_span);
+
+ self.diagnostic()
+ .struct_span_err(
+ range_span,
+ &format!("`X{}` range patterns are not supported", form),
+ )
+ .span_suggestion(
+ range_span,
+ "try using the maximum value for the type",
+ format!("{}{}MAX", pprust::expr_to_string(&begin), form),
+ Applicability::HasPlaceholders,
+ )
+ .emit();
+
+ Ok(self.mk_expr(range_span, ExprKind::Err, ThinVec::new()))
+ }
+ }
+
+ fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
+ if self.token.is_path_start() {
+ let lo = self.token.span;
+ let (qself, path) = if self.eat_lt() {
+ // Parse a qualified path
+ let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
+ (Some(qself), path)
+ } else {
+ // Parse an unqualified path
+ (None, self.parse_path(PathStyle::Expr)?)
+ };
+ let hi = self.prev_span;
+ Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path), ThinVec::new()))
+ } else {
+ self.parse_literal_maybe_minus()
+ }
+ }
+
+ /// Parses `ident` or `ident @ pat`.
+ /// used by the copy foo and ref foo patterns to give a good
+ /// error message when parsing mistakes like `ref foo(a, b)`.
+ fn parse_pat_ident(&mut self,
+ binding_mode: ast::BindingMode)
+ -> PResult<'a, PatKind> {
+ let ident = self.parse_ident()?;
+ let sub = if self.eat(&token::At) {
+ Some(self.parse_pat(Some("binding pattern"))?)
+ } else {
+ None
+ };
+
+ // just to be friendly, if they write something like
+ // ref Some(i)
+ // we end up here with ( as the current token. This shortly
+ // leads to a parse error. Note that if there is no explicit
+ // binding mode then we do not end up here, because the lookahead
+ // will direct us over to parse_enum_variant()
+ if self.token == token::OpenDelim(token::Paren) {
+ return Err(self.span_fatal(
+ self.prev_span,
+ "expected identifier, found enum pattern"))
+ }
+
+ Ok(PatKind::Ident(binding_mode, ident, sub))
+ }
+
+ /// Parses the fields of a struct-like pattern.
+ fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<Spanned<FieldPat>>, bool)> {
+ let mut fields = Vec::new();
+ let mut etc = false;
+ let mut ate_comma = true;
+ let mut delayed_err: Option<DiagnosticBuilder<'a>> = None;
+ let mut etc_span = None;
+
+ while self.token != token::CloseDelim(token::Brace) {
+ let attrs = match self.parse_outer_attributes() {
+ Ok(attrs) => attrs,
+ Err(err) => {
+ if let Some(mut delayed) = delayed_err {
+ delayed.emit();
+ }
+ return Err(err);
+ },
+ };
+ let lo = self.token.span;
+
+ // check that a comma comes after every field
+ if !ate_comma {
+ let err = self.struct_span_err(self.prev_span, "expected `,`");
+ if let Some(mut delayed) = delayed_err {
+ delayed.emit();
+ }
+ return Err(err);
+ }
+ ate_comma = false;
+
+ if self.check(&token::DotDot) || self.token == token::DotDotDot {
+ etc = true;
+ let mut etc_sp = self.token.span;
+
+ if self.token == token::DotDotDot { // Issue #46718
+ // Accept `...` as if it were `..` to avoid further errors
+ self.struct_span_err(self.token.span, "expected field pattern, found `...`")
+ .span_suggestion(
+ self.token.span,
+ "to omit remaining fields, use one fewer `.`",
+ "..".to_owned(),
+ Applicability::MachineApplicable
+ )
+ .emit();
+ }
+ self.bump(); // `..` || `...`
+
+ if self.token == token::CloseDelim(token::Brace) {
+ etc_span = Some(etc_sp);
+ break;
+ }
+ let token_str = self.this_token_descr();
+ let mut err = self.fatal(&format!("expected `}}`, found {}", token_str));
+
+ err.span_label(self.token.span, "expected `}`");
+ let mut comma_sp = None;
+ if self.token == token::Comma { // Issue #49257
+ let nw_span = self.sess.source_map().span_until_non_whitespace(self.token.span);
+ etc_sp = etc_sp.to(nw_span);
+ err.span_label(etc_sp,
+ "`..` must be at the end and cannot have a trailing comma");
+ comma_sp = Some(self.token.span);
+ self.bump();
+ ate_comma = true;
+ }
+
+ etc_span = Some(etc_sp.until(self.token.span));
+ if self.token == token::CloseDelim(token::Brace) {
+ // If the struct looks otherwise well formed, recover and continue.
+ if let Some(sp) = comma_sp {
+ err.span_suggestion_short(
+ sp,
+ "remove this comma",
+ String::new(),
+ Applicability::MachineApplicable,
+ );
+ }
+ err.emit();
+ break;
+ } else if self.token.is_ident() && ate_comma {
+ // Accept fields coming after `..,`.
+ // This way we avoid "pattern missing fields" errors afterwards.
+ // We delay this error until the end in order to have a span for a
+ // suggested fix.
+ if let Some(mut delayed_err) = delayed_err {
+ delayed_err.emit();
+ return Err(err);
+ } else {
+ delayed_err = Some(err);
+ }
+ } else {
+ if let Some(mut err) = delayed_err {
+ err.emit();
+ }
+ return Err(err);
+ }
+ }
+
+ fields.push(match self.parse_pat_field(lo, attrs) {
+ Ok(field) => field,
+ Err(err) => {
+ if let Some(mut delayed_err) = delayed_err {
+ delayed_err.emit();
+ }
+ return Err(err);
+ }
+ });
+ ate_comma = self.eat(&token::Comma);
+ }
+
+ if let Some(mut err) = delayed_err {
+ if let Some(etc_span) = etc_span {
+ err.multipart_suggestion(
+ "move the `..` to the end of the field list",
+ vec![
+ (etc_span, String::new()),
+ (self.token.span, format!("{}.. }}", if ate_comma { "" } else { ", " })),
+ ],
+ Applicability::MachineApplicable,
+ );
+ }
+ err.emit();
+ }
+ return Ok((fields, etc));
+ }
+
+ fn parse_pat_field(
+ &mut self,
+ lo: Span,
+ attrs: Vec<Attribute>
+ ) -> PResult<'a, Spanned<FieldPat>> {
+ // Check if a colon exists one ahead. This means we're parsing a fieldname.
+ let hi;
+ let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
+ // Parsing a pattern of the form "fieldname: pat"
+ let fieldname = self.parse_field_name()?;
+ self.bump();
+ let pat = self.parse_pat(None)?;
+ hi = pat.span;
+ (pat, fieldname, false)
+ } else {
+ // Parsing a pattern of the form "(box) (ref) (mut) fieldname"
+ let is_box = self.eat_keyword(kw::Box);
+ let boxed_span = self.token.span;
+ let is_ref = self.eat_keyword(kw::Ref);
+ let is_mut = self.eat_keyword(kw::Mut);
+ let fieldname = self.parse_ident()?;
+ hi = self.prev_span;
+
+ let bind_type = match (is_ref, is_mut) {
+ (true, true) => BindingMode::ByRef(Mutability::Mutable),
+ (true, false) => BindingMode::ByRef(Mutability::Immutable),
+ (false, true) => BindingMode::ByValue(Mutability::Mutable),
+ (false, false) => BindingMode::ByValue(Mutability::Immutable),
+ };
+
+ let fieldpat = self.mk_pat_ident(boxed_span.to(hi), bind_type, fieldname);
+ let subpat = if is_box {
+ self.mk_pat(lo.to(hi), PatKind::Box(fieldpat))
+ } else {
+ fieldpat
+ };
+ (subpat, fieldname, true)
+ };
+
+ Ok(Spanned {
+ span: lo.to(hi),
+ node: FieldPat {
+ ident: fieldname,
+ pat: subpat,
+ is_shorthand,
+ attrs: attrs.into(),
+ }
+ })
+ }
+
+ pub(super) fn mk_pat_ident(&self, span: Span, bm: BindingMode, ident: Ident) -> P<Pat> {
+ self.mk_pat(span, PatKind::Ident(bm, ident, None))
+ }
+
+ fn mk_pat(&self, span: Span, node: PatKind) -> P<Pat> {
+ P(Pat { node, span, id: ast::DUMMY_NODE_ID })
+ }
+}
--- /dev/null
+use super::{Parser, PResult, TokenType};
+
+use crate::{maybe_whole, ThinVec};
+use crate::ast::{self, QSelf, Path, PathSegment, Ident, ParenthesizedArgs, AngleBracketedArgs};
+use crate::ast::{AnonConst, GenericArg, AssocTyConstraint, AssocTyConstraintKind, BlockCheckMode};
+use crate::parse::token::{self, Token};
+use crate::source_map::{Span, BytePos};
+use crate::symbol::kw;
+
+use std::mem;
+use log::debug;
+use errors::{Applicability};
+
+/// Specifies how to parse a path.
+#[derive(Copy, Clone, PartialEq)]
+pub enum PathStyle {
+ /// In some contexts, notably in expressions, paths with generic arguments are ambiguous
+ /// with something else. For example, in expressions `segment < ....` can be interpreted
+ /// as a comparison and `segment ( ....` can be interpreted as a function call.
+ /// In all such contexts the non-path interpretation is preferred by default for practical
+ /// reasons, but the path interpretation can be forced by the disambiguator `::`, e.g.
+ /// `x<y>` - comparisons, `x::<y>` - unambiguously a path.
+ Expr,
+ /// In other contexts, notably in types, no ambiguity exists and paths can be written
+ /// without the disambiguator, e.g., `x<y>` - unambiguously a path.
+ /// Paths with disambiguators are still accepted, `x::<Y>` - unambiguously a path too.
+ Type,
+ /// A path with generic arguments disallowed, e.g., `foo::bar::Baz`, used in imports,
+ /// visibilities or attributes.
+ /// Technically, this variant is unnecessary and e.g., `Expr` can be used instead
+ /// (paths in "mod" contexts have to be checked later for absence of generic arguments
+ /// anyway, due to macros), but it is used to avoid weird suggestions about expected
+ /// tokens when something goes wrong.
+ Mod,
+}
+
+impl<'a> Parser<'a> {
+ /// Parses a qualified path.
+ /// Assumes that the leading `<` has been parsed already.
+ ///
+ /// `qualified_path = <type [as trait_ref]>::path`
+ ///
+ /// # Examples
+ /// `<T>::default`
+ /// `<T as U>::a`
+ /// `<T as U>::F::a<S>` (without disambiguator)
+ /// `<T as U>::F::a::<S>` (with disambiguator)
+ pub(super) fn parse_qpath(&mut self, style: PathStyle) -> PResult<'a, (QSelf, Path)> {
+ let lo = self.prev_span;
+ let ty = self.parse_ty()?;
+
+ // `path` will contain the prefix of the path up to the `>`,
+ // if any (e.g., `U` in the `<T as U>::*` examples
+ // above). `path_span` has the span of that path, or an empty
+ // span in the case of something like `<T>::Bar`.
+ let (mut path, path_span);
+ if self.eat_keyword(kw::As) {
+ let path_lo = self.token.span;
+ path = self.parse_path(PathStyle::Type)?;
+ path_span = path_lo.to(self.prev_span);
+ } else {
+ path_span = self.token.span.to(self.token.span);
+ path = ast::Path { segments: Vec::new(), span: path_span };
+ }
+
+ // See doc comment for `unmatched_angle_bracket_count`.
+ self.expect(&token::Gt)?;
+ if self.unmatched_angle_bracket_count > 0 {
+ self.unmatched_angle_bracket_count -= 1;
+ debug!("parse_qpath: (decrement) count={:?}", self.unmatched_angle_bracket_count);
+ }
+
+ self.expect(&token::ModSep)?;
+
+ let qself = QSelf { ty, path_span, position: path.segments.len() };
+ self.parse_path_segments(&mut path.segments, style)?;
+
+ Ok((qself, Path { segments: path.segments, span: lo.to(self.prev_span) }))
+ }
+
+ /// Parses simple paths.
+ ///
+ /// `path = [::] segment+`
+ /// `segment = ident | ident[::]<args> | ident[::](args) [-> type]`
+ ///
+ /// # Examples
+ /// `a::b::C<D>` (without disambiguator)
+ /// `a::b::C::<D>` (with disambiguator)
+ /// `Fn(Args)` (without disambiguator)
+ /// `Fn::(Args)` (with disambiguator)
+ pub fn parse_path(&mut self, style: PathStyle) -> PResult<'a, Path> {
+ maybe_whole!(self, NtPath, |path| {
+ if style == PathStyle::Mod &&
+ path.segments.iter().any(|segment| segment.args.is_some()) {
+ self.diagnostic().span_err(path.span, "unexpected generic arguments in path");
+ }
+ path
+ });
+
+ let lo = self.meta_var_span.unwrap_or(self.token.span);
+ let mut segments = Vec::new();
+ let mod_sep_ctxt = self.token.span.ctxt();
+ if self.eat(&token::ModSep) {
+ segments.push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
+ }
+ self.parse_path_segments(&mut segments, style)?;
+
+ Ok(Path { segments, span: lo.to(self.prev_span) })
+ }
+
+ /// Like `parse_path`, but also supports parsing `Word` meta items into paths for
+ /// backwards-compatibility. This is used when parsing derive macro paths in `#[derive]`
+ /// attributes.
+ pub fn parse_path_allowing_meta(&mut self, style: PathStyle) -> PResult<'a, Path> {
+ let meta_ident = match self.token.kind {
+ token::Interpolated(ref nt) => match **nt {
+ token::NtMeta(ref meta) => match meta.node {
+ ast::MetaItemKind::Word => Some(meta.path.clone()),
+ _ => None,
+ },
+ _ => None,
+ },
+ _ => None,
+ };
+ if let Some(path) = meta_ident {
+ self.bump();
+ return Ok(path);
+ }
+ self.parse_path(style)
+ }
+
+ crate fn parse_path_segments(&mut self,
+ segments: &mut Vec<PathSegment>,
+ style: PathStyle)
+ -> PResult<'a, ()> {
+ loop {
+ let segment = self.parse_path_segment(style)?;
+ if style == PathStyle::Expr {
+ // In order to check for trailing angle brackets, we must have finished
+ // recursing (`parse_path_segment` can indirectly call this function),
+ // that is, the next token must be the highlighted part of the below example:
+ //
+ // `Foo::<Bar as Baz<T>>::Qux`
+ // ^ here
+ //
+ // As opposed to the below highlight (if we had only finished the first
+ // recursion):
+ //
+ // `Foo::<Bar as Baz<T>>::Qux`
+ // ^ here
+ //
+ // `PathStyle::Expr` is only provided at the root invocation and never in
+ // `parse_path_segment` to recurse and therefore can be checked to maintain
+ // this invariant.
+ self.check_trailing_angle_brackets(&segment, token::ModSep);
+ }
+ segments.push(segment);
+
+ if self.is_import_coupler() || !self.eat(&token::ModSep) {
+ return Ok(());
+ }
+ }
+ }
+
+ pub(super) fn parse_path_segment(&mut self, style: PathStyle) -> PResult<'a, PathSegment> {
+ let ident = self.parse_path_segment_ident()?;
+
+ let is_args_start = |token: &Token| match token.kind {
+ token::Lt | token::BinOp(token::Shl) | token::OpenDelim(token::Paren)
+ | token::LArrow => true,
+ _ => false,
+ };
+ let check_args_start = |this: &mut Self| {
+ this.expected_tokens.extend_from_slice(
+ &[TokenType::Token(token::Lt), TokenType::Token(token::OpenDelim(token::Paren))]
+ );
+ is_args_start(&this.token)
+ };
+
+ Ok(if style == PathStyle::Type && check_args_start(self) ||
+ style != PathStyle::Mod && self.check(&token::ModSep)
+ && self.look_ahead(1, |t| is_args_start(t)) {
+ // We use `style == PathStyle::Expr` to check if this is in a recursion or not. If
+ // it isn't, then we reset the unmatched angle bracket count as we're about to start
+ // parsing a new path.
+ if style == PathStyle::Expr {
+ self.unmatched_angle_bracket_count = 0;
+ self.max_angle_bracket_count = 0;
+ }
+
+ // Generic arguments are found - `<`, `(`, `::<` or `::(`.
+ self.eat(&token::ModSep);
+ let lo = self.token.span;
+ let args = if self.eat_lt() {
+ // `<'a, T, A = U>`
+ let (args, constraints) =
+ self.parse_generic_args_with_leaning_angle_bracket_recovery(style, lo)?;
+ self.expect_gt()?;
+ let span = lo.to(self.prev_span);
+ AngleBracketedArgs { args, constraints, span }.into()
+ } else {
+ // `(T, U) -> R`
+ let (inputs, _) = self.parse_paren_comma_seq(|p| p.parse_ty())?;
+ let span = lo.to(self.prev_span);
+ let output = if self.eat(&token::RArrow) {
+ Some(self.parse_ty_common(false, false, false)?)
+ } else {
+ None
+ };
+ ParenthesizedArgs { inputs, output, span }.into()
+ };
+
+ PathSegment { ident, args, id: ast::DUMMY_NODE_ID }
+ } else {
+ // Generic arguments are not found.
+ PathSegment::from_ident(ident)
+ })
+ }
+
+ pub(super) fn parse_path_segment_ident(&mut self) -> PResult<'a, Ident> {
+ match self.token.kind {
+ token::Ident(name, _) if name.is_path_segment_keyword() => {
+ let span = self.token.span;
+ self.bump();
+ Ok(Ident::new(name, span))
+ }
+ _ => self.parse_ident(),
+ }
+ }
+
+ /// Parses generic args (within a path segment) with recovery for extra leading angle brackets.
+ /// For the purposes of understanding the parsing logic of generic arguments, this function
+ /// can be thought of being the same as just calling `self.parse_generic_args()` if the source
+ /// had the correct amount of leading angle brackets.
+ ///
+ /// ```ignore (diagnostics)
+ /// bar::<<<<T as Foo>::Output>();
+ /// ^^ help: remove extra angle brackets
+ /// ```
+ fn parse_generic_args_with_leaning_angle_bracket_recovery(
+ &mut self,
+ style: PathStyle,
+ lo: Span,
+ ) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> {
+ // We need to detect whether there are extra leading left angle brackets and produce an
+ // appropriate error and suggestion. This cannot be implemented by looking ahead at
+ // upcoming tokens for a matching `>` character - if there are unmatched `<` tokens
+ // then there won't be matching `>` tokens to find.
+ //
+ // To explain how this detection works, consider the following example:
+ //
+ // ```ignore (diagnostics)
+ // bar::<<<<T as Foo>::Output>();
+ // ^^ help: remove extra angle brackets
+ // ```
+ //
+ // Parsing of the left angle brackets starts in this function. We start by parsing the
+ // `<` token (incrementing the counter of unmatched angle brackets on `Parser` via
+ // `eat_lt`):
+ //
+ // *Upcoming tokens:* `<<<<T as Foo>::Output>;`
+ // *Unmatched count:* 1
+ // *`parse_path_segment` calls deep:* 0
+ //
+ // This has the effect of recursing as this function is called if a `<` character
+ // is found within the expected generic arguments:
+ //
+ // *Upcoming tokens:* `<<<T as Foo>::Output>;`
+ // *Unmatched count:* 2
+ // *`parse_path_segment` calls deep:* 1
+ //
+ // Eventually we will have recursed until having consumed all of the `<` tokens and
+ // this will be reflected in the count:
+ //
+ // *Upcoming tokens:* `T as Foo>::Output>;`
+ // *Unmatched count:* 4
+ // `parse_path_segment` calls deep:* 3
+ //
+ // The parser will continue until reaching the first `>` - this will decrement the
+ // unmatched angle bracket count and return to the parent invocation of this function
+ // having succeeded in parsing:
+ //
+ // *Upcoming tokens:* `::Output>;`
+ // *Unmatched count:* 3
+ // *`parse_path_segment` calls deep:* 2
+ //
+ // This will continue until the next `>` character which will also return successfully
+ // to the parent invocation of this function and decrement the count:
+ //
+ // *Upcoming tokens:* `;`
+ // *Unmatched count:* 2
+ // *`parse_path_segment` calls deep:* 1
+ //
+ // At this point, this function will expect to find another matching `>` character but
+ // won't be able to and will return an error. This will continue all the way up the
+ // call stack until the first invocation:
+ //
+ // *Upcoming tokens:* `;`
+ // *Unmatched count:* 2
+ // *`parse_path_segment` calls deep:* 0
+ //
+ // In doing this, we have managed to work out how many unmatched leading left angle
+ // brackets there are, but we cannot recover as the unmatched angle brackets have
+ // already been consumed. To remedy this, we keep a snapshot of the parser state
+ // before we do the above. We can then inspect whether we ended up with a parsing error
+ // and unmatched left angle brackets and if so, restore the parser state before we
+ // consumed any `<` characters to emit an error and consume the erroneous tokens to
+ // recover by attempting to parse again.
+ //
+ // In practice, the recursion of this function is indirect and there will be other
+ // locations that consume some `<` characters - as long as we update the count when
+ // this happens, it isn't an issue.
+
+ let is_first_invocation = style == PathStyle::Expr;
+ // Take a snapshot before attempting to parse - we can restore this later.
+ let snapshot = if is_first_invocation {
+ Some(self.clone())
+ } else {
+ None
+ };
+
+ debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
+ match self.parse_generic_args() {
+ Ok(value) => Ok(value),
+ Err(ref mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
+ // Cancel error from being unable to find `>`. We know the error
+ // must have been this due to a non-zero unmatched angle bracket
+ // count.
+ e.cancel();
+
+ // Swap `self` with our backup of the parser state before attempting to parse
+ // generic arguments.
+ let snapshot = mem::replace(self, snapshot.unwrap());
+
+ debug!(
+ "parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
+ snapshot.count={:?}",
+ snapshot.unmatched_angle_bracket_count,
+ );
+
+ // Eat the unmatched angle brackets.
+ for _ in 0..snapshot.unmatched_angle_bracket_count {
+ self.eat_lt();
+ }
+
+ // Make a span over ${unmatched angle bracket count} characters.
+ let span = lo.with_hi(
+ lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
+ );
+ let plural = snapshot.unmatched_angle_bracket_count > 1;
+ self.diagnostic()
+ .struct_span_err(
+ span,
+ &format!(
+ "unmatched angle bracket{}",
+ if plural { "s" } else { "" }
+ ),
+ )
+ .span_suggestion(
+ span,
+ &format!(
+ "remove extra angle bracket{}",
+ if plural { "s" } else { "" }
+ ),
+ String::new(),
+ Applicability::MachineApplicable,
+ )
+ .emit();
+
+ // Try again without unmatched angle bracket characters.
+ self.parse_generic_args()
+ },
+ Err(e) => Err(e),
+ }
+ }
+
+ /// Parses (possibly empty) list of lifetime and type arguments and associated type bindings,
+ /// possibly including trailing comma.
+ fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> {
+ let mut args = Vec::new();
+ let mut constraints = Vec::new();
+ let mut misplaced_assoc_ty_constraints: Vec<Span> = Vec::new();
+ let mut assoc_ty_constraints: Vec<Span> = Vec::new();
+
+ let args_lo = self.token.span;
+
+ loop {
+ if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
+ // Parse lifetime argument.
+ args.push(GenericArg::Lifetime(self.expect_lifetime()));
+ misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
+ } else if self.check_ident() && self.look_ahead(1,
+ |t| t == &token::Eq || t == &token::Colon) {
+ // Parse associated type constraint.
+ let lo = self.token.span;
+ let ident = self.parse_ident()?;
+ let kind = if self.eat(&token::Eq) {
+ AssocTyConstraintKind::Equality {
+ ty: self.parse_ty()?,
+ }
+ } else if self.eat(&token::Colon) {
+ AssocTyConstraintKind::Bound {
+ bounds: self.parse_generic_bounds(Some(self.prev_span))?,
+ }
+ } else {
+ unreachable!();
+ };
+ let span = lo.to(self.prev_span);
+ constraints.push(AssocTyConstraint {
+ id: ast::DUMMY_NODE_ID,
+ ident,
+ kind,
+ span,
+ });
+ assoc_ty_constraints.push(span);
+ } else if self.check_const_arg() {
+ // Parse const argument.
+ let expr = if let token::OpenDelim(token::Brace) = self.token.kind {
+ self.parse_block_expr(
+ None, self.token.span, BlockCheckMode::Default, ThinVec::new()
+ )?
+ } else if self.token.is_ident() {
+ // FIXME(const_generics): to distinguish between idents for types and consts,
+ // we should introduce a GenericArg::Ident in the AST and distinguish when
+ // lowering to the HIR. For now, idents for const args are not permitted.
+ if self.token.is_keyword(kw::True) || self.token.is_keyword(kw::False) {
+ self.parse_literal_maybe_minus()?
+ } else {
+ return Err(
+ self.fatal("identifiers may currently not be used for const generics")
+ );
+ }
+ } else {
+ self.parse_literal_maybe_minus()?
+ };
+ let value = AnonConst {
+ id: ast::DUMMY_NODE_ID,
+ value: expr,
+ };
+ args.push(GenericArg::Const(value));
+ misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
+ } else if self.check_type() {
+ // Parse type argument.
+ args.push(GenericArg::Type(self.parse_ty()?));
+ misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints);
+ } else {
+ break
+ }
+
+ if !self.eat(&token::Comma) {
+ break
+ }
+ }
+
+ // FIXME: we would like to report this in ast_validation instead, but we currently do not
+ // preserve ordering of generic parameters with respect to associated type binding, so we
+ // lose that information after parsing.
+ if misplaced_assoc_ty_constraints.len() > 0 {
+ let mut err = self.struct_span_err(
+ args_lo.to(self.prev_span),
+ "associated type bindings must be declared after generic parameters",
+ );
+ for span in misplaced_assoc_ty_constraints {
+ err.span_label(
+ span,
+ "this associated type binding should be moved after the generic parameters",
+ );
+ }
+ err.emit();
+ }
+
+ Ok((args, constraints))
+ }
+}
--- /dev/null
+use super::{Parser, PResult, Restrictions, PrevTokenKind, SemiColonMode, BlockMode};
+use super::expr::LhsExpr;
+use super::path::PathStyle;
+
+use crate::ptr::P;
+use crate::{maybe_whole, ThinVec};
+use crate::ast::{self, Stmt, StmtKind, Local, Block, BlockCheckMode, Expr, ExprKind};
+use crate::ast::{Attribute, AttrStyle, VisibilityKind, MacStmtStyle, Mac_, MacDelimiter};
+use crate::ext::base::DummyResult;
+use crate::parse::{classify, DirectoryOwnership};
+use crate::parse::diagnostics::Error;
+use crate::parse::token::{self};
+use crate::source_map::{respan, Span};
+use crate::symbol::{kw, sym};
+
+use std::mem;
+use errors::Applicability;
+
+impl<'a> Parser<'a> {
+ /// Parse a statement. This stops just before trailing semicolons on everything but items.
+ /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
+ pub fn parse_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
+ Ok(self.parse_stmt_(true))
+ }
+
+ fn parse_stmt_(&mut self, macro_legacy_warnings: bool) -> Option<Stmt> {
+ self.parse_stmt_without_recovery(macro_legacy_warnings).unwrap_or_else(|mut e| {
+ e.emit();
+ self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
+ None
+ })
+ }
+
+ fn parse_stmt_without_recovery(
+ &mut self,
+ macro_legacy_warnings: bool,
+ ) -> PResult<'a, Option<Stmt>> {
+ maybe_whole!(self, NtStmt, |x| Some(x));
+
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+
+ Ok(Some(if self.eat_keyword(kw::Let) {
+ Stmt {
+ id: ast::DUMMY_NODE_ID,
+ node: StmtKind::Local(self.parse_local(attrs.into())?),
+ span: lo.to(self.prev_span),
+ }
+ } else if let Some(macro_def) = self.eat_macro_def(
+ &attrs,
+ &respan(lo, VisibilityKind::Inherited),
+ lo,
+ )? {
+ Stmt {
+ id: ast::DUMMY_NODE_ID,
+ node: StmtKind::Item(macro_def),
+ span: lo.to(self.prev_span),
+ }
+ // Starts like a simple path, being careful to avoid contextual keywords
+ // such as a union items, item with `crate` visibility or auto trait items.
+ // Our goal here is to parse an arbitrary path `a::b::c` but not something that starts
+ // like a path (1 token), but it fact not a path.
+ // `union::b::c` - path, `union U { ... }` - not a path.
+ // `crate::b::c` - path, `crate struct S;` - not a path.
+ } else if self.token.is_path_start() &&
+ !self.token.is_qpath_start() &&
+ !self.is_union_item() &&
+ !self.is_crate_vis() &&
+ !self.is_auto_trait_item() &&
+ !self.is_async_fn() {
+ let path = self.parse_path(PathStyle::Expr)?;
+
+ if !self.eat(&token::Not) {
+ let expr = if self.check(&token::OpenDelim(token::Brace)) {
+ self.parse_struct_expr(lo, path, ThinVec::new())?
+ } else {
+ let hi = self.prev_span;
+ self.mk_expr(lo.to(hi), ExprKind::Path(None, path), ThinVec::new())
+ };
+
+ let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
+ let expr = this.parse_dot_or_call_expr_with(expr, lo, attrs.into())?;
+ this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
+ })?;
+
+ return Ok(Some(Stmt {
+ id: ast::DUMMY_NODE_ID,
+ node: StmtKind::Expr(expr),
+ span: lo.to(self.prev_span),
+ }));
+ }
+
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ let hi = self.prev_span;
+
+ let style = if delim == MacDelimiter::Brace {
+ MacStmtStyle::Braces
+ } else {
+ MacStmtStyle::NoBraces
+ };
+
+ let mac = respan(lo.to(hi), Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ });
+ let node = if delim == MacDelimiter::Brace ||
+ self.token == token::Semi || self.token == token::Eof {
+ StmtKind::Mac(P((mac, style, attrs.into())))
+ }
+ // We used to incorrectly stop parsing macro-expanded statements here.
+ // If the next token will be an error anyway but could have parsed with the
+ // earlier behavior, stop parsing here and emit a warning to avoid breakage.
+ else if macro_legacy_warnings &&
+ self.token.can_begin_expr() &&
+ match self.token.kind {
+ // These can continue an expression, so we can't stop parsing and warn.
+ token::OpenDelim(token::Paren) | token::OpenDelim(token::Bracket) |
+ token::BinOp(token::Minus) | token::BinOp(token::Star) |
+ token::BinOp(token::And) | token::BinOp(token::Or) |
+ token::AndAnd | token::OrOr |
+ token::DotDot | token::DotDotDot | token::DotDotEq => false,
+ _ => true,
+ } {
+ self.warn_missing_semicolon();
+ StmtKind::Mac(P((mac, style, attrs.into())))
+ } else {
+ let e = self.mk_expr(mac.span, ExprKind::Mac(mac), ThinVec::new());
+ let e = self.maybe_recover_from_bad_qpath(e, true)?;
+ let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
+ let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
+ StmtKind::Expr(e)
+ };
+ Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(hi),
+ node,
+ }
+ } else {
+ // FIXME: Bad copy of attrs
+ let old_directory_ownership =
+ mem::replace(&mut self.directory.ownership, DirectoryOwnership::UnownedViaBlock);
+ let item = self.parse_item_(attrs.clone(), false, true)?;
+ self.directory.ownership = old_directory_ownership;
+
+ match item {
+ Some(i) => Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(i.span),
+ node: StmtKind::Item(i),
+ },
+ None => {
+ let unused_attrs = |attrs: &[Attribute], s: &mut Self| {
+ if !attrs.is_empty() {
+ if s.prev_token_kind == PrevTokenKind::DocComment {
+ s.span_fatal_err(s.prev_span, Error::UselessDocComment).emit();
+ } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) {
+ s.span_err(
+ s.token.span, "expected statement after outer attribute"
+ );
+ }
+ }
+ };
+
+ // Do not attempt to parse an expression if we're done here.
+ if self.token == token::Semi {
+ unused_attrs(&attrs, self);
+ self.bump();
+ return Ok(None);
+ }
+
+ if self.token == token::CloseDelim(token::Brace) {
+ unused_attrs(&attrs, self);
+ return Ok(None);
+ }
+
+ // Remainder are line-expr stmts.
+ let e = self.parse_expr_res(
+ Restrictions::STMT_EXPR, Some(attrs.into()))?;
+ Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(e.span),
+ node: StmtKind::Expr(e),
+ }
+ }
+ }
+ }))
+ }
+
+ /// Parses a local variable declaration.
+ fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
+ let lo = self.prev_span;
+ let pat = self.parse_top_level_pat()?;
+
+ let (err, ty) = if self.eat(&token::Colon) {
+ // Save the state of the parser before parsing type normally, in case there is a `:`
+ // instead of an `=` typo.
+ let parser_snapshot_before_type = self.clone();
+ let colon_sp = self.prev_span;
+ match self.parse_ty() {
+ Ok(ty) => (None, Some(ty)),
+ Err(mut err) => {
+ // Rewind to before attempting to parse the type and continue parsing
+ let parser_snapshot_after_type = self.clone();
+ mem::replace(self, parser_snapshot_before_type);
+
+ let snippet = self.span_to_snippet(pat.span).unwrap();
+ err.span_label(pat.span, format!("while parsing the type for `{}`", snippet));
+ (Some((parser_snapshot_after_type, colon_sp, err)), None)
+ }
+ }
+ } else {
+ (None, None)
+ };
+ let init = match (self.parse_initializer(err.is_some()), err) {
+ (Ok(init), None) => { // init parsed, ty parsed
+ init
+ }
+ (Ok(init), Some((_, colon_sp, mut err))) => { // init parsed, ty error
+ // Could parse the type as if it were the initializer, it is likely there was a
+ // typo in the code: `:` instead of `=`. Add suggestion and emit the error.
+ err.span_suggestion_short(
+ colon_sp,
+ "use `=` if you meant to assign",
+ "=".to_string(),
+ Applicability::MachineApplicable
+ );
+ err.emit();
+ // As this was parsed successfully, continue as if the code has been fixed for the
+ // rest of the file. It will still fail due to the emitted error, but we avoid
+ // extra noise.
+ init
+ }
+ (Err(mut init_err), Some((snapshot, _, ty_err))) => { // init error, ty error
+ init_err.cancel();
+ // Couldn't parse the type nor the initializer, only raise the type error and
+ // return to the parser state before parsing the type as the initializer.
+ // let x: <parse_error>;
+ mem::replace(self, snapshot);
+ return Err(ty_err);
+ }
+ (Err(err), None) => { // init error, ty parsed
+ // Couldn't parse the initializer and we're not attempting to recover a failed
+ // parse of the type, return the error.
+ return Err(err);
+ }
+ };
+ let hi = if self.token == token::Semi {
+ self.token.span
+ } else {
+ self.prev_span
+ };
+ Ok(P(ast::Local {
+ ty,
+ pat,
+ init,
+ id: ast::DUMMY_NODE_ID,
+ span: lo.to(hi),
+ attrs,
+ }))
+ }
+
+ /// Parses the RHS of a local variable declaration (e.g., '= 14;').
+ fn parse_initializer(&mut self, skip_eq: bool) -> PResult<'a, Option<P<Expr>>> {
+ if self.eat(&token::Eq) {
+ Ok(Some(self.parse_expr()?))
+ } else if skip_eq {
+ Ok(Some(self.parse_expr()?))
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn is_auto_trait_item(&self) -> bool {
+ // auto trait
+ (self.token.is_keyword(kw::Auto) &&
+ self.is_keyword_ahead(1, &[kw::Trait]))
+ || // unsafe auto trait
+ (self.token.is_keyword(kw::Unsafe) &&
+ self.is_keyword_ahead(1, &[kw::Auto]) &&
+ self.is_keyword_ahead(2, &[kw::Trait]))
+ }
+
+ /// Parses a block. No inner attributes are allowed.
+ pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
+ maybe_whole!(self, NtBlock, |x| x);
+
+ let lo = self.token.span;
+
+ if !self.eat(&token::OpenDelim(token::Brace)) {
+ let sp = self.token.span;
+ let tok = self.this_token_descr();
+ let mut e = self.span_fatal(sp, &format!("expected `{{`, found {}", tok));
+ let do_not_suggest_help =
+ self.token.is_keyword(kw::In) || self.token == token::Colon;
+
+ if self.token.is_ident_named(sym::and) {
+ e.span_suggestion_short(
+ self.token.span,
+ "use `&&` instead of `and` for the boolean operator",
+ "&&".to_string(),
+ Applicability::MaybeIncorrect,
+ );
+ }
+ if self.token.is_ident_named(sym::or) {
+ e.span_suggestion_short(
+ self.token.span,
+ "use `||` instead of `or` for the boolean operator",
+ "||".to_string(),
+ Applicability::MaybeIncorrect,
+ );
+ }
+
+ // Check to see if the user has written something like
+ //
+ // if (cond)
+ // bar;
+ //
+ // Which is valid in other languages, but not Rust.
+ match self.parse_stmt_without_recovery(false) {
+ Ok(Some(stmt)) => {
+ if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
+ || do_not_suggest_help {
+ // if the next token is an open brace (e.g., `if a b {`), the place-
+ // inside-a-block suggestion would be more likely wrong than right
+ e.span_label(sp, "expected `{`");
+ return Err(e);
+ }
+ let mut stmt_span = stmt.span;
+ // expand the span to include the semicolon, if it exists
+ if self.eat(&token::Semi) {
+ stmt_span = stmt_span.with_hi(self.prev_span.hi());
+ }
+ if let Ok(snippet) = self.span_to_snippet(stmt_span) {
+ e.span_suggestion(
+ stmt_span,
+ "try placing this code inside a block",
+ format!("{{ {} }}", snippet),
+ // speculative, has been misleading in the past (#46836)
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ Err(mut e) => {
+ self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
+ self.cancel(&mut e);
+ }
+ _ => ()
+ }
+ e.span_label(sp, "expected `{`");
+ return Err(e);
+ }
+
+ self.parse_block_tail(lo, BlockCheckMode::Default)
+ }
+
+ /// Parses a block. Inner attributes are allowed.
+ crate fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
+ maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
+
+ let lo = self.token.span;
+ self.expect(&token::OpenDelim(token::Brace))?;
+ Ok((self.parse_inner_attributes()?,
+ self.parse_block_tail(lo, BlockCheckMode::Default)?))
+ }
+
+ /// Parses the rest of a block expression or function body.
+ /// Precondition: already parsed the '{'.
+ pub(super) fn parse_block_tail(
+ &mut self,
+ lo: Span,
+ s: BlockCheckMode
+ ) -> PResult<'a, P<Block>> {
+ let mut stmts = vec![];
+ while !self.eat(&token::CloseDelim(token::Brace)) {
+ if self.token == token::Eof {
+ break;
+ }
+ let stmt = match self.parse_full_stmt(false) {
+ Err(mut err) => {
+ err.emit();
+ self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
+ Some(Stmt {
+ id: ast::DUMMY_NODE_ID,
+ node: StmtKind::Expr(DummyResult::raw_expr(self.token.span, true)),
+ span: self.token.span,
+ })
+ }
+ Ok(stmt) => stmt,
+ };
+ if let Some(stmt) = stmt {
+ stmts.push(stmt);
+ } else {
+ // Found only `;` or `}`.
+ continue;
+ };
+ }
+ Ok(P(ast::Block {
+ stmts,
+ id: ast::DUMMY_NODE_ID,
+ rules: s,
+ span: lo.to(self.prev_span),
+ }))
+ }
+
+ /// Parses a statement, including the trailing semicolon.
+ crate fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
+ // skip looking for a trailing semicolon when we have an interpolated statement
+ maybe_whole!(self, NtStmt, |x| Some(x));
+
+ let mut stmt = match self.parse_stmt_without_recovery(macro_legacy_warnings)? {
+ Some(stmt) => stmt,
+ None => return Ok(None),
+ };
+
+ match stmt.node {
+ StmtKind::Expr(ref expr) if self.token != token::Eof => {
+ // expression without semicolon
+ if classify::expr_requires_semi_to_be_stmt(expr) {
+ // Just check for errors and recover; do not eat semicolon yet.
+ if let Err(mut e) =
+ self.expect_one_of(&[], &[token::Semi, token::CloseDelim(token::Brace)])
+ {
+ e.emit();
+ self.recover_stmt();
+ // Don't complain about type errors in body tail after parse error (#57383).
+ let sp = expr.span.to(self.prev_span);
+ stmt.node = StmtKind::Expr(DummyResult::raw_expr(sp, true));
+ }
+ }
+ }
+ StmtKind::Local(..) => {
+ // We used to incorrectly allow a macro-expanded let statement to lack a semicolon.
+ if macro_legacy_warnings && self.token != token::Semi {
+ self.warn_missing_semicolon();
+ } else {
+ self.expect_one_of(&[], &[token::Semi])?;
+ }
+ }
+ _ => {}
+ }
+
+ if self.eat(&token::Semi) {
+ stmt = stmt.add_trailing_semicolon();
+ }
+ stmt.span = stmt.span.to(self.prev_span);
+ Ok(Some(stmt))
+ }
+
+ fn warn_missing_semicolon(&self) {
+ self.diagnostic().struct_span_warn(self.token.span, {
+ &format!("expected `;`, found {}", self.this_token_descr())
+ }).note({
+ "This was erroneously allowed and will become a hard error in a future release"
+ }).emit();
+ }
+}
--- /dev/null
+use super::{Parser, PResult, PathStyle, PrevTokenKind, TokenType};
+
+use crate::{maybe_whole, maybe_recover_from_interpolated_ty_qpath};
+use crate::ptr::P;
+use crate::ast::{self, Ty, TyKind, MutTy, BareFnTy, FunctionRetTy, GenericParam, Lifetime, Ident};
+use crate::ast::{TraitBoundModifier, TraitObjectSyntax, GenericBound, GenericBounds, PolyTraitRef};
+use crate::ast::{Mutability, AnonConst, FnDecl, Mac_};
+use crate::parse::token::{self, Token};
+use crate::source_map::{respan, Span};
+use crate::symbol::{kw};
+
+use rustc_target::spec::abi::Abi;
+
+use errors::{Applicability};
+
+/// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
+/// `IDENT<<u8 as Trait>::AssocTy>`.
+///
+/// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes
+/// that `IDENT` is not the ident of a fn trait.
+fn can_continue_type_after_non_fn_ident(t: &Token) -> bool {
+ t == &token::ModSep || t == &token::Lt ||
+ t == &token::BinOp(token::Shl)
+}
+
+impl<'a> Parser<'a> {
+ /// Parses a type.
+ pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
+ self.parse_ty_common(true, true, false)
+ }
+
+ /// Parses a type in restricted contexts where `+` is not permitted.
+ ///
+ /// Example 1: `&'a TYPE`
+ /// `+` is prohibited to maintain operator priority (P(+) < P(&)).
+ /// Example 2: `value1 as TYPE + value2`
+ /// `+` is prohibited to avoid interactions with expression grammar.
+ pub(super) fn parse_ty_no_plus(&mut self) -> PResult<'a, P<Ty>> {
+ self.parse_ty_common(false, true, false)
+ }
+
+ /// Parses an optional return type `[ -> TY ]` in a function declaration.
+ pub(super) fn parse_ret_ty(&mut self, allow_plus: bool) -> PResult<'a, FunctionRetTy> {
+ if self.eat(&token::RArrow) {
+ Ok(FunctionRetTy::Ty(self.parse_ty_common(allow_plus, true, false)?))
+ } else {
+ Ok(FunctionRetTy::Default(self.token.span.shrink_to_lo()))
+ }
+ }
+
+ pub(super) fn parse_ty_common(&mut self, allow_plus: bool, allow_qpath_recovery: bool,
+ allow_c_variadic: bool) -> PResult<'a, P<Ty>> {
+ maybe_recover_from_interpolated_ty_qpath!(self, allow_qpath_recovery);
+ maybe_whole!(self, NtTy, |x| x);
+
+ let lo = self.token.span;
+ let mut impl_dyn_multi = false;
+ let node = if self.eat(&token::OpenDelim(token::Paren)) {
+ // `(TYPE)` is a parenthesized type.
+ // `(TYPE,)` is a tuple with a single field of type TYPE.
+ let mut ts = vec![];
+ let mut last_comma = false;
+ while self.token != token::CloseDelim(token::Paren) {
+ ts.push(self.parse_ty()?);
+ if self.eat(&token::Comma) {
+ last_comma = true;
+ } else {
+ last_comma = false;
+ break;
+ }
+ }
+ let trailing_plus = self.prev_token_kind == PrevTokenKind::Plus;
+ self.expect(&token::CloseDelim(token::Paren))?;
+
+ if ts.len() == 1 && !last_comma {
+ let ty = ts.into_iter().nth(0).unwrap().into_inner();
+ let maybe_bounds = allow_plus && self.token.is_like_plus();
+ match ty.node {
+ // `(TY_BOUND_NOPAREN) + BOUND + ...`.
+ TyKind::Path(None, ref path) if maybe_bounds => {
+ self.parse_remaining_bounds(Vec::new(), path.clone(), lo, true)?
+ }
+ TyKind::TraitObject(ref bounds, TraitObjectSyntax::None)
+ if maybe_bounds && bounds.len() == 1 && !trailing_plus => {
+ let path = match bounds[0] {
+ GenericBound::Trait(ref pt, ..) => pt.trait_ref.path.clone(),
+ GenericBound::Outlives(..) => self.bug("unexpected lifetime bound"),
+ };
+ self.parse_remaining_bounds(Vec::new(), path, lo, true)?
+ }
+ // `(TYPE)`
+ _ => TyKind::Paren(P(ty))
+ }
+ } else {
+ TyKind::Tup(ts)
+ }
+ } else if self.eat(&token::Not) {
+ // Never type `!`
+ TyKind::Never
+ } else if self.eat(&token::BinOp(token::Star)) {
+ // Raw pointer
+ TyKind::Ptr(self.parse_ptr()?)
+ } else if self.eat(&token::OpenDelim(token::Bracket)) {
+ // Array or slice
+ let t = self.parse_ty()?;
+ // Parse optional `; EXPR` in `[TYPE; EXPR]`
+ let t = match self.maybe_parse_fixed_length_of_vec()? {
+ None => TyKind::Slice(t),
+ Some(length) => TyKind::Array(t, AnonConst {
+ id: ast::DUMMY_NODE_ID,
+ value: length,
+ }),
+ };
+ self.expect(&token::CloseDelim(token::Bracket))?;
+ t
+ } else if self.check(&token::BinOp(token::And)) || self.check(&token::AndAnd) {
+ // Reference
+ self.expect_and()?;
+ self.parse_borrowed_pointee()?
+ } else if self.eat_keyword_noexpect(kw::Typeof) {
+ // `typeof(EXPR)`
+ // In order to not be ambiguous, the type must be surrounded by parens.
+ self.expect(&token::OpenDelim(token::Paren))?;
+ let e = AnonConst {
+ id: ast::DUMMY_NODE_ID,
+ value: self.parse_expr()?,
+ };
+ self.expect(&token::CloseDelim(token::Paren))?;
+ TyKind::Typeof(e)
+ } else if self.eat_keyword(kw::Underscore) {
+ // A type to be inferred `_`
+ TyKind::Infer
+ } else if self.token_is_bare_fn_keyword() {
+ // Function pointer type
+ self.parse_ty_bare_fn(Vec::new())?
+ } else if self.check_keyword(kw::For) {
+ // Function pointer type or bound list (trait object type) starting with a poly-trait.
+ // `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T`
+ // `for<'lt> Trait1<'lt> + Trait2 + 'a`
+ let lo = self.token.span;
+ let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
+ if self.token_is_bare_fn_keyword() {
+ self.parse_ty_bare_fn(lifetime_defs)?
+ } else {
+ let path = self.parse_path(PathStyle::Type)?;
+ let parse_plus = allow_plus && self.check_plus();
+ self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)?
+ }
+ } else if self.eat_keyword(kw::Impl) {
+ // Always parse bounds greedily for better error recovery.
+ let bounds = self.parse_generic_bounds(None)?;
+ impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
+ TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)
+ } else if self.check_keyword(kw::Dyn) &&
+ (self.token.span.rust_2018() ||
+ self.look_ahead(1, |t| t.can_begin_bound() &&
+ !can_continue_type_after_non_fn_ident(t))) {
+ self.bump(); // `dyn`
+ // Always parse bounds greedily for better error recovery.
+ let bounds = self.parse_generic_bounds(None)?;
+ impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus;
+ TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn)
+ } else if self.check(&token::Question) ||
+ self.check_lifetime() && self.look_ahead(1, |t| t.is_like_plus()) {
+ // Bound list (trait object type)
+ TyKind::TraitObject(self.parse_generic_bounds_common(allow_plus, None)?,
+ TraitObjectSyntax::None)
+ } else if self.eat_lt() {
+ // Qualified path
+ let (qself, path) = self.parse_qpath(PathStyle::Type)?;
+ TyKind::Path(Some(qself), path)
+ } else if self.token.is_path_start() {
+ // Simple path
+ let path = self.parse_path(PathStyle::Type)?;
+ if self.eat(&token::Not) {
+ // Macro invocation in type position
+ let (delim, tts) = self.expect_delimited_token_tree()?;
+ let node = Mac_ {
+ path,
+ tts,
+ delim,
+ prior_type_ascription: self.last_type_ascription,
+ };
+ TyKind::Mac(respan(lo.to(self.prev_span), node))
+ } else {
+ // Just a type path or bound list (trait object type) starting with a trait.
+ // `Type`
+ // `Trait1 + Trait2 + 'a`
+ if allow_plus && self.check_plus() {
+ self.parse_remaining_bounds(Vec::new(), path, lo, true)?
+ } else {
+ TyKind::Path(None, path)
+ }
+ }
+ } else if self.check(&token::DotDotDot) {
+ if allow_c_variadic {
+ self.eat(&token::DotDotDot);
+ TyKind::CVarArgs
+ } else {
+ return Err(self.fatal(
+ "only foreign functions are allowed to be C-variadic"
+ ));
+ }
+ } else {
+ let msg = format!("expected type, found {}", self.this_token_descr());
+ let mut err = self.fatal(&msg);
+ err.span_label(self.token.span, "expected type");
+ self.maybe_annotate_with_ascription(&mut err, true);
+ return Err(err);
+ };
+
+ let span = lo.to(self.prev_span);
+ let ty = P(Ty { node, span, id: ast::DUMMY_NODE_ID });
+
+ // Try to recover from use of `+` with incorrect priority.
+ self.maybe_report_ambiguous_plus(allow_plus, impl_dyn_multi, &ty);
+ self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?;
+ self.maybe_recover_from_bad_qpath(ty, allow_qpath_recovery)
+ }
+
+ fn parse_remaining_bounds(&mut self, generic_params: Vec<GenericParam>, path: ast::Path,
+ lo: Span, parse_plus: bool) -> PResult<'a, TyKind> {
+ let poly_trait_ref = PolyTraitRef::new(generic_params, path, lo.to(self.prev_span));
+ let mut bounds = vec![GenericBound::Trait(poly_trait_ref, TraitBoundModifier::None)];
+ if parse_plus {
+ self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded
+ bounds.append(&mut self.parse_generic_bounds(Some(self.prev_span))?);
+ }
+ Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None))
+ }
+
+ fn parse_ptr(&mut self) -> PResult<'a, MutTy> {
+ let mutbl = if self.eat_keyword(kw::Mut) {
+ Mutability::Mutable
+ } else if self.eat_keyword(kw::Const) {
+ Mutability::Immutable
+ } else {
+ let span = self.prev_span;
+ let msg = "expected mut or const in raw pointer type";
+ self.struct_span_err(span, msg)
+ .span_label(span, msg)
+ .help("use `*mut T` or `*const T` as appropriate")
+ .emit();
+ Mutability::Immutable
+ };
+ let t = self.parse_ty_no_plus()?;
+ Ok(MutTy { ty: t, mutbl })
+ }
+
+ fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<'a, Option<P<ast::Expr>>> {
+ if self.eat(&token::Semi) {
+ Ok(Some(self.parse_expr()?))
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> {
+ let opt_lifetime = if self.check_lifetime() { Some(self.expect_lifetime()) } else { None };
+ let mutbl = self.parse_mutability();
+ let ty = self.parse_ty_no_plus()?;
+ return Ok(TyKind::Rptr(opt_lifetime, MutTy { ty, mutbl }));
+ }
+
+ /// Is the current token one of the keywords that signals a bare function type?
+ fn token_is_bare_fn_keyword(&mut self) -> bool {
+ self.check_keyword(kw::Fn) ||
+ self.check_keyword(kw::Unsafe) ||
+ self.check_keyword(kw::Extern)
+ }
+
+ /// Parses a `TyKind::BareFn` type.
+ fn parse_ty_bare_fn(&mut self, generic_params: Vec<GenericParam>) -> PResult<'a, TyKind> {
+ /*
+
+ [unsafe] [extern "ABI"] fn (S) -> T
+ ^~~~^ ^~~~^ ^~^ ^
+ | | | |
+ | | | Return type
+ | | Argument types
+ | |
+ | ABI
+ Function Style
+ */
+
+ let unsafety = self.parse_unsafety();
+ let abi = if self.eat_keyword(kw::Extern) {
+ self.parse_opt_abi()?.unwrap_or(Abi::C)
+ } else {
+ Abi::Rust
+ };
+
+ self.expect_keyword(kw::Fn)?;
+ let (inputs, c_variadic) = self.parse_fn_args(false, true)?;
+ let ret_ty = self.parse_ret_ty(false)?;
+ let decl = P(FnDecl {
+ inputs,
+ output: ret_ty,
+ c_variadic,
+ });
+ Ok(TyKind::BareFn(P(BareFnTy {
+ abi,
+ unsafety,
+ generic_params,
+ decl,
+ })))
+ }
+
+ crate fn parse_generic_bounds(&mut self,
+ colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
+ self.parse_generic_bounds_common(true, colon_span)
+ }
+
+ /// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`.
+ ///
+ /// ```
+ /// BOUND = TY_BOUND | LT_BOUND
+ /// LT_BOUND = LIFETIME (e.g., `'a`)
+ /// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
+ /// TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g., `?for<'a: 'b> m::Trait<'a>`)
+ /// ```
+ fn parse_generic_bounds_common(&mut self,
+ allow_plus: bool,
+ colon_span: Option<Span>) -> PResult<'a, GenericBounds> {
+ let mut bounds = Vec::new();
+ let mut negative_bounds = Vec::new();
+ let mut last_plus_span = None;
+ let mut was_negative = false;
+ loop {
+ // This needs to be synchronized with `TokenKind::can_begin_bound`.
+ let is_bound_start = self.check_path() || self.check_lifetime() ||
+ self.check(&token::Not) || // used for error reporting only
+ self.check(&token::Question) ||
+ self.check_keyword(kw::For) ||
+ self.check(&token::OpenDelim(token::Paren));
+ if is_bound_start {
+ let lo = self.token.span;
+ let has_parens = self.eat(&token::OpenDelim(token::Paren));
+ let inner_lo = self.token.span;
+ let is_negative = self.eat(&token::Not);
+ let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
+ if self.token.is_lifetime() {
+ if let Some(question_span) = question {
+ self.span_err(question_span,
+ "`?` may only modify trait bounds, not lifetime bounds");
+ }
+ bounds.push(GenericBound::Outlives(self.expect_lifetime()));
+ if has_parens {
+ let inner_span = inner_lo.to(self.prev_span);
+ self.expect(&token::CloseDelim(token::Paren))?;
+ let mut err = self.struct_span_err(
+ lo.to(self.prev_span),
+ "parenthesized lifetime bounds are not supported"
+ );
+ if let Ok(snippet) = self.span_to_snippet(inner_span) {
+ err.span_suggestion_short(
+ lo.to(self.prev_span),
+ "remove the parentheses",
+ snippet.to_owned(),
+ Applicability::MachineApplicable
+ );
+ }
+ err.emit();
+ }
+ } else {
+ let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
+ let path = self.parse_path(PathStyle::Type)?;
+ if has_parens {
+ self.expect(&token::CloseDelim(token::Paren))?;
+ }
+ let poly_span = lo.to(self.prev_span);
+ if is_negative {
+ was_negative = true;
+ if let Some(sp) = last_plus_span.or(colon_span) {
+ negative_bounds.push(sp.to(poly_span));
+ }
+ } else {
+ let poly_trait = PolyTraitRef::new(lifetime_defs, path, poly_span);
+ let modifier = if question.is_some() {
+ TraitBoundModifier::Maybe
+ } else {
+ TraitBoundModifier::None
+ };
+ bounds.push(GenericBound::Trait(poly_trait, modifier));
+ }
+ }
+ } else {
+ break
+ }
+
+ if !allow_plus || !self.eat_plus() {
+ break
+ } else {
+ last_plus_span = Some(self.prev_span);
+ }
+ }
+
+ if !negative_bounds.is_empty() || was_negative {
+ let plural = negative_bounds.len() > 1;
+ let last_span = negative_bounds.last().map(|sp| *sp);
+ let mut err = self.struct_span_err(
+ negative_bounds,
+ "negative trait bounds are not supported",
+ );
+ if let Some(sp) = last_span {
+ err.span_label(sp, "negative trait bounds are not supported");
+ }
+ if let Some(bound_list) = colon_span {
+ let bound_list = bound_list.to(self.prev_span);
+ let mut new_bound_list = String::new();
+ if !bounds.is_empty() {
+ let mut snippets = bounds.iter().map(|bound| bound.span())
+ .map(|span| self.span_to_snippet(span));
+ while let Some(Ok(snippet)) = snippets.next() {
+ new_bound_list.push_str(" + ");
+ new_bound_list.push_str(&snippet);
+ }
+ new_bound_list = new_bound_list.replacen(" +", ":", 1);
+ }
+ err.span_suggestion_hidden(
+ bound_list,
+ &format!("remove the trait bound{}", if plural { "s" } else { "" }),
+ new_bound_list,
+ Applicability::MachineApplicable,
+ );
+ }
+ err.emit();
+ }
+
+ return Ok(bounds);
+ }
+
+ pub(super) fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<GenericParam>> {
+ if self.eat_keyword(kw::For) {
+ self.expect_lt()?;
+ let params = self.parse_generic_params()?;
+ self.expect_gt()?;
+ // We rely on AST validation to rule out invalid cases: There must not be type
+ // parameters, and the lifetime parameters must not have bounds.
+ Ok(params)
+ } else {
+ Ok(Vec::new())
+ }
+ }
+
+ crate fn check_lifetime(&mut self) -> bool {
+ self.expected_tokens.push(TokenType::Lifetime);
+ self.token.is_lifetime()
+ }
+
+ /// Parses a single lifetime `'a` or panics.
+ crate fn expect_lifetime(&mut self) -> Lifetime {
+ if let Some(ident) = self.token.lifetime() {
+ let span = self.token.span;
+ self.bump();
+ Lifetime { ident: Ident::new(ident.name, span), id: ast::DUMMY_NODE_ID }
+ } else {
+ self.span_bug(self.token.span, "not a lifetime")
+ }
+ }
+}
fn main() {
{
- ::std::io::_print(::std::fmt::Arguments::new_v1(&["rust\n"],
- &match () {
- () => [],
- }));
+ ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"],
+ &match () {
+ () => [],
+ }));
};
}
((::alloc::fmt::format as
- for<'r> fn(std::fmt::Arguments<'r>) -> std::string::String {std::fmt::format})(((<::std::fmt::Arguments>::new_v1
+ for<'r> fn(std::fmt::Arguments<'r>) -> std::string::String {std::fmt::format})(((<::core::fmt::Arguments>::new_v1
as
fn(&[&str], &[std::fmt::ArgumentV1<'_>]) -> std::fmt::Arguments<'_> {std::fmt::Arguments::<'_>::new_v1})((&([("test"
as
#![feature(box_syntax)]
#![feature(rustc_private)]
-extern crate serialize;
-use serialize as rustc_serialize;
+extern crate serialize as rustc_serialize;
-use serialize::{Encodable, Decodable};
-use serialize::json;
+use rustc_serialize::{Encodable, Decodable};
+use rustc_serialize::json;
#[derive(RustcEncodable, RustcDecodable)]
struct A {
#![feature(rustc_private)]
-extern crate serialize;
-use serialize as rustc_serialize;
+extern crate serialize as rustc_serialize;
use std::cell::{Cell, RefCell};
-use serialize::{Encodable, Decodable};
-use serialize::json;
+use rustc_serialize::{Encodable, Decodable};
+use rustc_serialize::json;
#[derive(RustcEncodable, RustcDecodable)]
struct A {
#![feature(rustc_private)]
-extern crate serialize;
-use serialize as rustc_serialize;
+extern crate serialize as rustc_serialize;
mod submod {
// if any of these are implemented without global calls for any
#![allow(non_upper_case_globals)]
#![feature(rustc_private)]
-extern crate serialize;
-use serialize as rustc_serialize;
+extern crate serialize as rustc_serialize;
pub const other: u8 = 1;
pub const f: u8 = 1;
#![feature(rustc_private)]
-extern crate serialize;
-use serialize as rustc_serialize;
+extern crate serialize as rustc_serialize;
use std::io::Cursor;
use std::io::prelude::*;
use std::fmt;
use std::slice;
-use serialize::{Encodable, Encoder};
-use serialize::json;
-use serialize::opaque;
+use rustc_serialize::{Encodable, Encoder};
+use rustc_serialize::json;
+use rustc_serialize::opaque;
#[derive(RustcEncodable)]
struct Foo {
--- /dev/null
+// build-pass
+// Regression test for #56870: Internal compiler error (traits & associated consts)
+
+use std::fmt::Debug;
+
+pub trait Foo<T> {
+ const FOO: *const u8;
+}
+
+impl <T: Debug> Foo<T> for dyn Debug {
+ const FOO: *const u8 = <T as Debug>::fmt as *const u8;
+}
+
+pub trait Bar {
+ const BAR: *const u8;
+}
+
+pub trait Baz {
+ type Data: Debug;
+}
+
+pub struct BarStruct<S: Baz>(S);
+
+impl<S: Baz> Bar for BarStruct<S> {
+ const BAR: *const u8 = <dyn Debug as Foo<<S as Baz>::Data>>::FOO;
+}
+
+struct AnotherStruct;
+#[derive(Debug)]
+struct SomeStruct;
+
+impl Baz for AnotherStruct {
+ type Data = SomeStruct;
+}
+
+fn main() {
+ let _x = <BarStruct<AnotherStruct> as Bar>::BAR;
+}
+#![allow(non_camel_case_types)]
+
+enum E { A, B, c }
+
+mod m {
+ const CONST1: usize = 10;
+ const Const2: usize = 20;
+}
+
fn main() {
let y = 1;
match y {
a | b => {} //~ ERROR variable `a` is not bound in all patterns
- //~^ ERROR variable `b` is not bound in all patterns
+ //~| ERROR variable `b` is not bound in all patterns
+ }
+
+ let x = (E::A, E::B);
+ match x {
+ (A, B) | (ref B, c) | (c, A) => ()
+ //~^ ERROR variable `A` is not bound in all patterns
+ //~| ERROR variable `B` is not bound in all patterns
+ //~| ERROR variable `B` is bound in inconsistent ways
+ //~| ERROR mismatched types
+ //~| ERROR variable `c` is not bound in all patterns
+ //~| HELP consider making the path in the pattern qualified: `?::A`
+ }
+
+ let z = (10, 20);
+ match z {
+ (CONST1, _) | (_, Const2) => ()
+ //~^ ERROR variable `CONST1` is not bound in all patterns
+ //~| HELP consider making the path in the pattern qualified: `?::CONST1`
+ //~| ERROR variable `Const2` is not bound in all patterns
+ //~| HELP consider making the path in the pattern qualified: `?::Const2`
}
}
error[E0408]: variable `a` is not bound in all patterns
- --> $DIR/resolve-inconsistent-names.rs:4:12
+ --> $DIR/resolve-inconsistent-names.rs:13:12
|
LL | a | b => {}
| - ^ pattern doesn't bind `a`
| variable not in all patterns
error[E0408]: variable `b` is not bound in all patterns
- --> $DIR/resolve-inconsistent-names.rs:4:8
+ --> $DIR/resolve-inconsistent-names.rs:13:8
|
LL | a | b => {}
| ^ - variable not in all patterns
| |
| pattern doesn't bind `b`
-error: aborting due to 2 previous errors
+error[E0408]: variable `A` is not bound in all patterns
+ --> $DIR/resolve-inconsistent-names.rs:19:18
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | - ^^^^^^^^^^ - variable not in all patterns
+ | | |
+ | | pattern doesn't bind `A`
+ | variable not in all patterns
+ |
+help: if you meant to match on a variant or a `const` item, consider making the path in the pattern qualified: `?::A`
+ --> $DIR/resolve-inconsistent-names.rs:19:10
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | ^
+
+error[E0408]: variable `B` is not bound in all patterns
+ --> $DIR/resolve-inconsistent-names.rs:19:31
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | - - ^^^^^^ pattern doesn't bind `B`
+ | | |
+ | | variable not in all patterns
+ | variable not in all patterns
+
+error[E0408]: variable `c` is not bound in all patterns
+ --> $DIR/resolve-inconsistent-names.rs:19:9
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | ^^^^^^ - - variable not in all patterns
+ | | |
+ | | variable not in all patterns
+ | pattern doesn't bind `c`
+
+error[E0409]: variable `B` is bound in inconsistent ways within the same match arm
+ --> $DIR/resolve-inconsistent-names.rs:19:23
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | - ^ bound in different ways
+ | |
+ | first binding
+
+error[E0408]: variable `CONST1` is not bound in all patterns
+ --> $DIR/resolve-inconsistent-names.rs:30:23
+ |
+LL | (CONST1, _) | (_, Const2) => ()
+ | ------ ^^^^^^^^^^^ pattern doesn't bind `CONST1`
+ | |
+ | variable not in all patterns
+ |
+help: if you meant to match on a variant or a `const` item, consider making the path in the pattern qualified: `?::CONST1`
+ --> $DIR/resolve-inconsistent-names.rs:30:10
+ |
+LL | (CONST1, _) | (_, Const2) => ()
+ | ^^^^^^
+
+error[E0408]: variable `Const2` is not bound in all patterns
+ --> $DIR/resolve-inconsistent-names.rs:30:9
+ |
+LL | (CONST1, _) | (_, Const2) => ()
+ | ^^^^^^^^^^^ ------ variable not in all patterns
+ | |
+ | pattern doesn't bind `Const2`
+ |
+help: if you meant to match on a variant or a `const` item, consider making the path in the pattern qualified: `?::Const2`
+ --> $DIR/resolve-inconsistent-names.rs:30:27
+ |
+LL | (CONST1, _) | (_, Const2) => ()
+ | ^^^^^^
+
+error[E0308]: mismatched types
+ --> $DIR/resolve-inconsistent-names.rs:19:19
+ |
+LL | (A, B) | (ref B, c) | (c, A) => ()
+ | ^^^^^ expected enum `E`, found &E
+ |
+ = note: expected type `E`
+ found type `&E`
+
+error: aborting due to 9 previous errors
-For more information about this error, try `rustc --explain E0408`.
+Some errors have detailed explanations: E0308, E0408, E0409.
+For more information about an error, try `rustc --explain E0308`.
--- /dev/null
+// ignore-tidy-linelength
+#![feature(type_alias_impl_trait)]
+
+use std::fmt::Debug;
+
+pub trait Foo {
+ type Item: Debug;
+
+ fn foo<T: Debug>(_: T) -> Self::Item;
+}
+
+#[derive(Debug)]
+pub struct S<T>(std::marker::PhantomData<T>);
+
+pub struct S2;
+
+impl Foo for S2 {
+ type Item = impl Debug;
+
+ fn foo<T: Debug>(_: T) -> Self::Item {
+ //~^ Error type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+ S::<T>(Default::default())
+ }
+}
+
+fn main() {
+ S2::foo(123);
+}
--- /dev/null
+error: type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+ --> $DIR/issue-53598.rs:20:42
+ |
+LL | fn foo<T: Debug>(_: T) -> Self::Item {
+ | __________________________________________^
+LL | |
+LL | | S::<T>(Default::default())
+LL | | }
+ | |_____^
+
+error: aborting due to previous error
+
--- /dev/null
+// ignore-tidy-linelength
+#![feature(arbitrary_self_types)]
+#![feature(type_alias_impl_trait)]
+
+use std::ops::Deref;
+
+trait Foo {
+ type Bar: Foo;
+
+ fn foo(self: impl Deref<Target = Self>) -> Self::Bar;
+}
+
+impl<C> Foo for C {
+ type Bar = impl Foo;
+
+ fn foo(self: impl Deref<Target = Self>) -> Self::Bar {
+ //~^ Error type parameter `impl Deref<Target = Self>` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+ self
+ }
+}
+
+fn main() {}
--- /dev/null
+error: type parameter `impl Deref<Target = Self>` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+ --> $DIR/issue-57700.rs:16:58
+ |
+LL | fn foo(self: impl Deref<Target = Self>) -> Self::Bar {
+ | __________________________________________________________^
+LL | |
+LL | | self
+LL | | }
+ | |_____^
+
+error: aborting due to previous error
+
projects / rust.git / commitdiff