-// ignore-tidy-filelength
-
//! Lowers the AST to the HIR.
//!
//! Since the AST and HIR are fairly similar, this is mostly a simple procedure,
//! in the HIR, especially for multiple identifiers.
#![feature(array_value_iter)]
+#![feature(crate_visibility_modifier)]
use rustc::arena::Arena;
use rustc::dep_graph::DepGraph;
use rustc::hir::map::definitions::{DefKey, DefPathData, Definitions};
use rustc::hir::map::Map;
-use rustc::lint;
-use rustc::lint::builtin::{self, ELIDED_LIFETIMES_IN_PATHS};
-use rustc::middle::cstore::CrateStore;
-use rustc::util::captures::Captures;
-use rustc::util::common::FN_OUTPUT_NAME;
use rustc::{bug, span_bug};
+use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::sync::Lrc;
use rustc_error_codes::*;
-use rustc_errors::{struct_span_err, Applicability};
+use rustc_errors::struct_span_err;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
use rustc_hir::def_id::{DefId, DefIdMap, DefIndex, CRATE_DEF_INDEX};
use rustc_hir::{ConstArg, GenericArg, ParamName};
use rustc_index::vec::IndexVec;
use rustc_session::config::nightly_options;
+use rustc_session::lint::{builtin, BuiltinLintDiagnostics, LintBuffer};
use rustc_session::node_id::NodeMap;
use rustc_session::Session;
use rustc_span::hygiene::ExpnId;
-use rustc_span::source_map::{respan, DesugaringKind, ExpnData, ExpnKind, Spanned};
+use rustc_span::source_map::{respan, DesugaringKind, ExpnData, ExpnKind};
use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::Span;
use syntax::ast;
use syntax::ast::*;
use syntax::attr;
use syntax::print::pprust;
-use syntax::ptr::P as AstP;
use syntax::sess::ParseSess;
use syntax::token::{self, Nonterminal, Token};
use syntax::tokenstream::{TokenStream, TokenTree};
mod expr;
mod item;
+mod pat;
+mod path;
const HIR_ID_COUNTER_LOCKED: u32 = 0xFFFFFFFF;
}
pub trait Resolver {
- fn cstore(&self) -> &dyn CrateStore;
+ fn def_key(&mut self, id: DefId) -> DefKey;
+
+ fn item_generics_num_lifetimes(&self, def: DefId, sess: &Session) -> usize;
/// Obtains resolution for a `NodeId` with a single resolution.
fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes>;
ns: Namespace,
) -> (ast::Path, Res<NodeId>);
- fn lint_buffer(&mut self) -> &mut lint::LintBuffer;
+ fn lint_buffer(&mut self) -> &mut LintBuffer;
fn next_node_id(&mut self) -> NodeId;
}
// incr. comp. yet.
dep_graph.assert_ignored();
- let _prof_timer = sess.prof.generic_activity("hir_lowering");
+ let _prof_timer = sess.prof.verbose_generic_activity("hir_lowering");
LoweringContext {
crate_root: sess.parse_sess.injected_crate_name.try_get().copied(),
}
}
- fn with_hir_id_owner<F, T>(&mut self, owner: Option<NodeId>, f: F) -> T
- where
- F: FnOnce(&mut Self) -> T,
- {
+ fn with_hir_id_owner<T>(
+ &mut self,
+ owner: Option<NodeId>,
+ f: impl FnOnce(&mut Self) -> T,
+ ) -> T {
let old = mem::replace(&mut self.hir_id_owner, owner);
let r = f(self);
self.hir_id_owner = old;
}
}
- impl<'tcx, 'lowering, 'hir> Visitor<'tcx> for MiscCollector<'tcx, 'lowering, 'hir> {
+ impl<'tcx> Visitor<'tcx> for MiscCollector<'tcx, '_, '_> {
fn visit_pat(&mut self, p: &'tcx Pat) {
if let PatKind::Paren(..) | PatKind::Rest = p.kind {
// Doesn't generate a HIR node
lowered
}
- fn lower_node_id_generic<F>(&mut self, ast_node_id: NodeId, alloc_hir_id: F) -> hir::HirId
- where
- F: FnOnce(&mut Self) -> hir::HirId,
- {
+ fn lower_node_id_generic(
+ &mut self,
+ ast_node_id: NodeId,
+ alloc_hir_id: impl FnOnce(&mut Self) -> hir::HirId,
+ ) -> hir::HirId {
if ast_node_id == DUMMY_NODE_ID {
return hir::DUMMY_HIR_ID;
}
}
}
- fn with_hir_id_owner<F, T>(&mut self, owner: NodeId, f: F) -> T
- where
- F: FnOnce(&mut Self) -> T,
- {
+ fn with_hir_id_owner<T>(&mut self, owner: NodeId, f: impl FnOnce(&mut Self) -> T) -> T {
let counter = self
.item_local_id_counters
.insert(owner, HIR_ID_COUNTER_LOCKED)
/// Presuming that in-band lifetimes are enabled, then
/// `self.anonymous_lifetime_mode` will be updated to match the
/// parameter while `f` is running (and restored afterwards).
- fn collect_in_band_defs<T, F>(
+ fn collect_in_band_defs<T>(
&mut self,
parent_id: DefId,
anonymous_lifetime_mode: AnonymousLifetimeMode,
- f: F,
- ) -> (Vec<hir::GenericParam<'hir>>, T)
- where
- F: FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T),
- {
+ f: impl FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T),
+ ) -> (Vec<hir::GenericParam<'hir>>, T) {
assert!(!self.is_collecting_in_band_lifetimes);
assert!(self.lifetimes_to_define.is_empty());
let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode;
// This is used to track which lifetimes have already been defined, and
// which are new in-band lifetimes that need to have a definition created
// for them.
- fn with_in_scope_lifetime_defs<T, F>(&mut self, params: &[GenericParam], f: F) -> T
- where
- F: FnOnce(&mut Self) -> T,
- {
+ fn with_in_scope_lifetime_defs<T>(
+ &mut self,
+ params: &[GenericParam],
+ f: impl FnOnce(&mut Self) -> T,
+ ) -> T {
let old_len = self.in_scope_lifetimes.len();
let lt_def_names = params.iter().filter_map(|param| match param.kind {
GenericParamKind::Lifetime { .. } => Some(ParamName::Plain(param.ident.modern())),
/// Presuming that in-band lifetimes are enabled, then
/// `self.anonymous_lifetime_mode` will be updated to match the
/// parameter while `f` is running (and restored afterwards).
- fn add_in_band_defs<F, T>(
+ fn add_in_band_defs<T>(
&mut self,
generics: &Generics,
parent_id: DefId,
anonymous_lifetime_mode: AnonymousLifetimeMode,
- f: F,
- ) -> (hir::Generics<'hir>, T)
- where
- F: FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T,
- {
+ f: impl FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T,
+ ) -> (hir::Generics<'hir>, T) {
let (in_band_defs, (mut lowered_generics, res)) =
self.with_in_scope_lifetime_defs(&generics.params, |this| {
this.collect_in_band_defs(parent_id, anonymous_lifetime_mode, |this| {
(lowered_generics, res)
}
- fn with_dyn_type_scope<T, F>(&mut self, in_scope: bool, f: F) -> T
- where
- F: FnOnce(&mut Self) -> T,
- {
+ fn with_dyn_type_scope<T>(&mut self, in_scope: bool, f: impl FnOnce(&mut Self) -> T) -> T {
let was_in_dyn_type = self.is_in_dyn_type;
self.is_in_dyn_type = in_scope;
result
}
- fn with_new_scopes<T, F>(&mut self, f: F) -> T
- where
- F: FnOnce(&mut Self) -> T,
- {
+ fn with_new_scopes<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
let was_in_loop_condition = self.is_in_loop_condition;
self.is_in_loop_condition = false;
ret
}
- fn def_key(&mut self, id: DefId) -> DefKey {
- if id.is_local() {
- self.resolver.definitions().def_key(id.index)
- } else {
- self.resolver.cstore().def_key(id)
- }
- }
-
fn lower_attrs(&mut self, attrs: &[Attribute]) -> &'hir [Attribute] {
self.arena.alloc_from_iter(attrs.iter().map(|a| self.lower_attr(a)))
}
)
}
- fn lower_qpath(
- &mut self,
- id: NodeId,
- qself: &Option<QSelf>,
- p: &Path,
- param_mode: ParamMode,
- mut itctx: ImplTraitContext<'_, 'hir>,
- ) -> hir::QPath<'hir> {
- let qself_position = qself.as_ref().map(|q| q.position);
- let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx.reborrow()));
-
- let partial_res =
- self.resolver.get_partial_res(id).unwrap_or_else(|| PartialRes::new(Res::Err));
-
- let proj_start = p.segments.len() - partial_res.unresolved_segments();
- let path = self.arena.alloc(hir::Path {
- res: self.lower_res(partial_res.base_res()),
- segments: self.arena.alloc_from_iter(p.segments[..proj_start].iter().enumerate().map(
- |(i, segment)| {
- let param_mode = match (qself_position, param_mode) {
- (Some(j), ParamMode::Optional) if i < j => {
- // This segment is part of the trait path in a
- // qualified path - one of `a`, `b` or `Trait`
- // in `<X as a::b::Trait>::T::U::method`.
- ParamMode::Explicit
- }
- _ => param_mode,
- };
-
- // Figure out if this is a type/trait segment,
- // which may need lifetime elision performed.
- let parent_def_id = |this: &mut Self, def_id: DefId| DefId {
- krate: def_id.krate,
- index: this.def_key(def_id).parent.expect("missing parent"),
- };
- let type_def_id = match partial_res.base_res() {
- Res::Def(DefKind::AssocTy, def_id) if i + 2 == proj_start => {
- Some(parent_def_id(self, def_id))
- }
- Res::Def(DefKind::Variant, def_id) if i + 1 == proj_start => {
- Some(parent_def_id(self, def_id))
- }
- Res::Def(DefKind::Struct, def_id)
- | Res::Def(DefKind::Union, def_id)
- | Res::Def(DefKind::Enum, def_id)
- | Res::Def(DefKind::TyAlias, def_id)
- | Res::Def(DefKind::Trait, def_id)
- if i + 1 == proj_start =>
- {
- Some(def_id)
- }
- _ => None,
- };
- let parenthesized_generic_args = match partial_res.base_res() {
- // `a::b::Trait(Args)`
- Res::Def(DefKind::Trait, _) if i + 1 == proj_start => {
- ParenthesizedGenericArgs::Ok
- }
- // `a::b::Trait(Args)::TraitItem`
- Res::Def(DefKind::Method, _)
- | Res::Def(DefKind::AssocConst, _)
- | Res::Def(DefKind::AssocTy, _)
- if i + 2 == proj_start =>
- {
- ParenthesizedGenericArgs::Ok
- }
- // Avoid duplicated errors.
- Res::Err => ParenthesizedGenericArgs::Ok,
- // An error
- _ => ParenthesizedGenericArgs::Err,
- };
-
- let num_lifetimes = type_def_id.map_or(0, |def_id| {
- if let Some(&n) = self.type_def_lifetime_params.get(&def_id) {
- return n;
- }
- assert!(!def_id.is_local());
- let item_generics = self
- .resolver
- .cstore()
- .item_generics_cloned_untracked(def_id, self.sess);
- let n = item_generics.own_counts().lifetimes;
- self.type_def_lifetime_params.insert(def_id, n);
- n
- });
- self.lower_path_segment(
- p.span,
- segment,
- param_mode,
- num_lifetimes,
- parenthesized_generic_args,
- itctx.reborrow(),
- None,
- )
- },
- )),
- span: p.span,
- });
-
- // Simple case, either no projections, or only fully-qualified.
- // E.g., `std::mem::size_of` or `<I as Iterator>::Item`.
- if partial_res.unresolved_segments() == 0 {
- return hir::QPath::Resolved(qself, path);
- }
-
- // Create the innermost type that we're projecting from.
- let mut ty = if path.segments.is_empty() {
- // If the base path is empty that means there exists a
- // syntactical `Self`, e.g., `&i32` in `<&i32>::clone`.
- qself.expect("missing QSelf for <T>::...")
- } else {
- // Otherwise, the base path is an implicit `Self` type path,
- // e.g., `Vec` in `Vec::new` or `<I as Iterator>::Item` in
- // `<I as Iterator>::Item::default`.
- let new_id = self.next_id();
- self.arena.alloc(self.ty_path(new_id, p.span, hir::QPath::Resolved(qself, path)))
- };
-
- // Anything after the base path are associated "extensions",
- // out of which all but the last one are associated types,
- // e.g., for `std::vec::Vec::<T>::IntoIter::Item::clone`:
- // * base path is `std::vec::Vec<T>`
- // * "extensions" are `IntoIter`, `Item` and `clone`
- // * type nodes are:
- // 1. `std::vec::Vec<T>` (created above)
- // 2. `<std::vec::Vec<T>>::IntoIter`
- // 3. `<<std::vec::Vec<T>>::IntoIter>::Item`
- // * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone`
- for (i, segment) in p.segments.iter().enumerate().skip(proj_start) {
- let segment = self.arena.alloc(self.lower_path_segment(
- p.span,
- segment,
- param_mode,
- 0,
- ParenthesizedGenericArgs::Err,
- itctx.reborrow(),
- None,
- ));
- let qpath = hir::QPath::TypeRelative(ty, segment);
-
- // It's finished, return the extension of the right node type.
- if i == p.segments.len() - 1 {
- return qpath;
- }
-
- // Wrap the associated extension in another type node.
- let new_id = self.next_id();
- ty = self.arena.alloc(self.ty_path(new_id, p.span, qpath));
- }
-
- // We should've returned in the for loop above.
- span_bug!(
- p.span,
- "lower_qpath: no final extension segment in {}..{}",
- proj_start,
- p.segments.len()
- )
- }
-
- fn lower_path_extra(
- &mut self,
- res: Res,
- p: &Path,
- param_mode: ParamMode,
- explicit_owner: Option<NodeId>,
- ) -> &'hir hir::Path<'hir> {
- self.arena.alloc(hir::Path {
- res,
- segments: self.arena.alloc_from_iter(p.segments.iter().map(|segment| {
- self.lower_path_segment(
- p.span,
- segment,
- param_mode,
- 0,
- ParenthesizedGenericArgs::Err,
- ImplTraitContext::disallowed(),
- explicit_owner,
- )
- })),
- span: p.span,
- })
- }
-
- fn lower_path(&mut self, id: NodeId, p: &Path, param_mode: ParamMode) -> &'hir hir::Path<'hir> {
- let res = self.expect_full_res(id);
- let res = self.lower_res(res);
- self.lower_path_extra(res, p, param_mode, None)
- }
-
- fn lower_path_segment(
- &mut self,
- path_span: Span,
- segment: &PathSegment,
- param_mode: ParamMode,
- expected_lifetimes: usize,
- parenthesized_generic_args: ParenthesizedGenericArgs,
- itctx: ImplTraitContext<'_, 'hir>,
- explicit_owner: Option<NodeId>,
- ) -> hir::PathSegment<'hir> {
- let (mut generic_args, infer_args) = if let Some(ref generic_args) = segment.args {
- let msg = "parenthesized type parameters may only be used with a `Fn` trait";
- match **generic_args {
- GenericArgs::AngleBracketed(ref data) => {
- self.lower_angle_bracketed_parameter_data(data, param_mode, itctx)
- }
- GenericArgs::Parenthesized(ref data) => match parenthesized_generic_args {
- ParenthesizedGenericArgs::Ok => self.lower_parenthesized_parameter_data(data),
- ParenthesizedGenericArgs::Err => {
- let mut err = struct_span_err!(self.sess, data.span, E0214, "{}", msg);
- err.span_label(data.span, "only `Fn` traits may use parentheses");
- if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
- // Do not suggest going from `Trait()` to `Trait<>`
- if data.inputs.len() > 0 {
- if let Some(split) = snippet.find('(') {
- let trait_name = &snippet[0..split];
- let args = &snippet[split + 1..snippet.len() - 1];
- err.span_suggestion(
- data.span,
- "use angle brackets instead",
- format!("{}<{}>", trait_name, args),
- Applicability::MaybeIncorrect,
- );
- }
- }
- };
- err.emit();
- (
- self.lower_angle_bracketed_parameter_data(
- &data.as_angle_bracketed_args(),
- param_mode,
- itctx,
- )
- .0,
- false,
- )
- }
- },
- }
- } else {
- self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode, itctx)
- };
-
- let has_lifetimes = generic_args.args.iter().any(|arg| match arg {
- GenericArg::Lifetime(_) => true,
- _ => false,
- });
- let first_generic_span = generic_args
- .args
- .iter()
- .map(|a| a.span())
- .chain(generic_args.bindings.iter().map(|b| b.span))
- .next();
- if !generic_args.parenthesized && !has_lifetimes {
- generic_args.args = self
- .elided_path_lifetimes(path_span, expected_lifetimes)
- .map(|lt| GenericArg::Lifetime(lt))
- .chain(generic_args.args.into_iter())
- .collect();
- if expected_lifetimes > 0 && param_mode == ParamMode::Explicit {
- let anon_lt_suggestion = vec!["'_"; expected_lifetimes].join(", ");
- let no_non_lt_args = generic_args.args.len() == expected_lifetimes;
- let no_bindings = generic_args.bindings.is_empty();
- let (incl_angl_brckt, insertion_sp, suggestion) = if no_non_lt_args && no_bindings {
- // If there are no (non-implicit) generic args or associated type
- // bindings, our suggestion includes the angle brackets.
- (true, path_span.shrink_to_hi(), format!("<{}>", anon_lt_suggestion))
- } else {
- // Otherwise (sorry, this is kind of gross) we need to infer the
- // place to splice in the `'_, ` from the generics that do exist.
- let first_generic_span = first_generic_span
- .expect("already checked that non-lifetime args or bindings exist");
- (false, first_generic_span.shrink_to_lo(), format!("{}, ", anon_lt_suggestion))
- };
- match self.anonymous_lifetime_mode {
- // In create-parameter mode we error here because we don't want to support
- // deprecated impl elision in new features like impl elision and `async fn`,
- // both of which work using the `CreateParameter` mode:
- //
- // impl Foo for std::cell::Ref<u32> // note lack of '_
- // async fn foo(_: std::cell::Ref<u32>) { ... }
- AnonymousLifetimeMode::CreateParameter => {
- let mut err = struct_span_err!(
- self.sess,
- path_span,
- E0726,
- "implicit elided lifetime not allowed here"
- );
- crate::lint::builtin::add_elided_lifetime_in_path_suggestion(
- &self.sess,
- &mut err,
- expected_lifetimes,
- path_span,
- incl_angl_brckt,
- insertion_sp,
- suggestion,
- );
- err.emit();
- }
- AnonymousLifetimeMode::PassThrough | AnonymousLifetimeMode::ReportError => {
- self.resolver.lint_buffer().buffer_lint_with_diagnostic(
- ELIDED_LIFETIMES_IN_PATHS,
- CRATE_NODE_ID,
- path_span,
- "hidden lifetime parameters in types are deprecated",
- builtin::BuiltinLintDiagnostics::ElidedLifetimesInPaths(
- expected_lifetimes,
- path_span,
- incl_angl_brckt,
- insertion_sp,
- suggestion,
- ),
- );
- }
- }
- }
- }
-
- let res = self.expect_full_res(segment.id);
- let id = if let Some(owner) = explicit_owner {
- self.lower_node_id_with_owner(segment.id, owner)
- } else {
- self.lower_node_id(segment.id)
- };
- debug!(
- "lower_path_segment: ident={:?} original-id={:?} new-id={:?}",
- segment.ident, segment.id, id,
- );
-
- hir::PathSegment {
- ident: segment.ident,
- hir_id: Some(id),
- res: Some(self.lower_res(res)),
- infer_args,
- args: if generic_args.is_empty() {
- None
- } else {
- Some(self.arena.alloc(generic_args.into_generic_args(self.arena)))
- },
- }
- }
-
- fn lower_angle_bracketed_parameter_data(
- &mut self,
- data: &AngleBracketedArgs,
- param_mode: ParamMode,
- mut itctx: ImplTraitContext<'_, 'hir>,
- ) -> (GenericArgsCtor<'hir>, bool) {
- let &AngleBracketedArgs { ref args, ref constraints, .. } = data;
- let has_non_lt_args = args.iter().any(|arg| match arg {
- ast::GenericArg::Lifetime(_) => false,
- ast::GenericArg::Type(_) => true,
- ast::GenericArg::Const(_) => true,
- });
- (
- GenericArgsCtor {
- args: args.iter().map(|a| self.lower_generic_arg(a, itctx.reborrow())).collect(),
- bindings: self.arena.alloc_from_iter(
- constraints.iter().map(|b| self.lower_assoc_ty_constraint(b, itctx.reborrow())),
- ),
- parenthesized: false,
- },
- !has_non_lt_args && param_mode == ParamMode::Optional,
- )
- }
-
- fn lower_parenthesized_parameter_data(
- &mut self,
- data: &ParenthesizedArgs,
- ) -> (GenericArgsCtor<'hir>, bool) {
- // Switch to `PassThrough` mode for anonymous lifetimes; this
- // means that we permit things like `&Ref<T>`, where `Ref` has
- // a hidden lifetime parameter. This is needed for backwards
- // compatibility, even in contexts like an impl header where
- // we generally don't permit such things (see #51008).
- self.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| {
- let &ParenthesizedArgs { ref inputs, ref output, span } = data;
- let inputs = this.arena.alloc_from_iter(
- inputs.iter().map(|ty| this.lower_ty_direct(ty, ImplTraitContext::disallowed())),
- );
- let output_ty = match output {
- FunctionRetTy::Ty(ty) => this.lower_ty(&ty, ImplTraitContext::disallowed()),
- FunctionRetTy::Default(_) => this.arena.alloc(this.ty_tup(span, &[])),
- };
- let args = smallvec![GenericArg::Type(this.ty_tup(span, inputs))];
- let binding = hir::TypeBinding {
- hir_id: this.next_id(),
- ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
- span: output_ty.span,
- kind: hir::TypeBindingKind::Equality { ty: output_ty },
- };
- (
- GenericArgsCtor { args, bindings: arena_vec![this; binding], parenthesized: true },
- false,
- )
- })
- }
-
fn lower_local(&mut self, l: &Local) -> (hir::Local<'hir>, SmallVec<[NodeId; 1]>) {
let mut ids = SmallVec::<[NodeId; 1]>::new();
if self.sess.features_untracked().impl_trait_in_bindings {
// "<Output = T>"
let future_params = self.arena.alloc(hir::GenericArgs {
args: &[],
- bindings: arena_vec![self; hir::TypeBinding {
- ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
- kind: hir::TypeBindingKind::Equality { ty: output_ty },
- hir_id: self.next_id(),
- span,
- }],
+ bindings: arena_vec![self; self.output_ty_binding(span, output_ty)],
parenthesized: false,
});
(hir::ParamName::Plain(param.ident), kind)
}
- GenericParamKind::Const { ref ty } => (
- hir::ParamName::Plain(param.ident),
- hir::GenericParamKind::Const {
- ty: self.lower_ty(&ty, ImplTraitContext::disallowed()),
- },
- ),
+ GenericParamKind::Const { ref ty } => {
+ let ty = self
+ .with_anonymous_lifetime_mode(AnonymousLifetimeMode::ReportError, |this| {
+ this.lower_ty(&ty, ImplTraitContext::disallowed())
+ });
+
+ (hir::ParamName::Plain(param.ident), hir::GenericParamKind::Const { ty })
+ }
};
hir::GenericParam {
self.expr_block(block, AttrVec::new())
}
- fn lower_pat(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
- let node = match p.kind {
- PatKind::Wild => hir::PatKind::Wild,
- PatKind::Ident(ref binding_mode, ident, ref sub) => {
- let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
- let node = self.lower_pat_ident(p, binding_mode, ident, lower_sub);
- node
- }
- PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
- PatKind::TupleStruct(ref path, ref pats) => {
- let qpath = self.lower_qpath(
- p.id,
- &None,
- path,
- ParamMode::Optional,
- ImplTraitContext::disallowed(),
- );
- let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
- hir::PatKind::TupleStruct(qpath, pats, ddpos)
- }
- PatKind::Or(ref pats) => {
- hir::PatKind::Or(self.arena.alloc_from_iter(pats.iter().map(|x| self.lower_pat(x))))
- }
- PatKind::Path(ref qself, ref path) => {
- let qpath = self.lower_qpath(
- p.id,
- qself,
- path,
- ParamMode::Optional,
- ImplTraitContext::disallowed(),
- );
- hir::PatKind::Path(qpath)
- }
- PatKind::Struct(ref path, ref fields, etc) => {
- let qpath = self.lower_qpath(
- p.id,
- &None,
- path,
- ParamMode::Optional,
- ImplTraitContext::disallowed(),
- );
-
- let fs = self.arena.alloc_from_iter(fields.iter().map(|f| hir::FieldPat {
- hir_id: self.next_id(),
- ident: f.ident,
- pat: self.lower_pat(&f.pat),
- is_shorthand: f.is_shorthand,
- span: f.span,
- }));
- hir::PatKind::Struct(qpath, fs, etc)
- }
- PatKind::Tuple(ref pats) => {
- let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");
- hir::PatKind::Tuple(pats, ddpos)
- }
- PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
- PatKind::Ref(ref inner, mutbl) => hir::PatKind::Ref(self.lower_pat(inner), mutbl),
- PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => hir::PatKind::Range(
- self.lower_expr(e1),
- self.lower_expr(e2),
- self.lower_range_end(end),
- ),
- PatKind::Slice(ref pats) => self.lower_pat_slice(pats),
- PatKind::Rest => {
- // If we reach here the `..` pattern is not semantically allowed.
- self.ban_illegal_rest_pat(p.span)
- }
- PatKind::Paren(ref inner) => return self.lower_pat(inner),
- PatKind::Mac(_) => panic!("Shouldn't exist here"),
- };
-
- self.pat_with_node_id_of(p, node)
- }
-
- fn lower_pat_tuple(
- &mut self,
- pats: &[AstP<Pat>],
- ctx: &str,
- ) -> (&'hir [&'hir hir::Pat<'hir>], Option<usize>) {
- let mut elems = Vec::with_capacity(pats.len());
- let mut rest = None;
-
- let mut iter = pats.iter().enumerate();
- for (idx, pat) in iter.by_ref() {
- // Interpret the first `..` pattern as a sub-tuple pattern.
- // Note that unlike for slice patterns,
- // where `xs @ ..` is a legal sub-slice pattern,
- // it is not a legal sub-tuple pattern.
- if pat.is_rest() {
- rest = Some((idx, pat.span));
- break;
- }
- // It was not a sub-tuple pattern so lower it normally.
- elems.push(self.lower_pat(pat));
- }
-
- for (_, pat) in iter {
- // There was a previous sub-tuple pattern; make sure we don't allow more...
- if pat.is_rest() {
- // ...but there was one again, so error.
- self.ban_extra_rest_pat(pat.span, rest.unwrap().1, ctx);
- } else {
- elems.push(self.lower_pat(pat));
- }
- }
-
- (self.arena.alloc_from_iter(elems), rest.map(|(ddpos, _)| ddpos))
- }
-
- /// Lower a slice pattern of form `[pat_0, ..., pat_n]` into
- /// `hir::PatKind::Slice(before, slice, after)`.
- ///
- /// When encountering `($binding_mode $ident @)? ..` (`slice`),
- /// this is interpreted as a sub-slice pattern semantically.
- /// Patterns that follow, which are not like `slice` -- or an error occurs, are in `after`.
- fn lower_pat_slice(&mut self, pats: &[AstP<Pat>]) -> hir::PatKind<'hir> {
- let mut before = Vec::new();
- let mut after = Vec::new();
- let mut slice = None;
- let mut prev_rest_span = None;
-
- let mut iter = pats.iter();
- // Lower all the patterns until the first occurence of a sub-slice pattern.
- for pat in iter.by_ref() {
- match pat.kind {
- // Found a sub-slice pattern `..`. Record, lower it to `_`, and stop here.
- PatKind::Rest => {
- prev_rest_span = Some(pat.span);
- slice = Some(self.pat_wild_with_node_id_of(pat));
- break;
- }
- // Found a sub-slice pattern `$binding_mode $ident @ ..`.
- // Record, lower it to `$binding_mode $ident @ _`, and stop here.
- PatKind::Ident(ref bm, ident, Some(ref sub)) if sub.is_rest() => {
- prev_rest_span = Some(sub.span);
- let lower_sub = |this: &mut Self| Some(this.pat_wild_with_node_id_of(sub));
- let node = self.lower_pat_ident(pat, bm, ident, lower_sub);
- slice = Some(self.pat_with_node_id_of(pat, node));
- break;
- }
- // It was not a subslice pattern so lower it normally.
- _ => before.push(self.lower_pat(pat)),
- }
- }
-
- // Lower all the patterns after the first sub-slice pattern.
- for pat in iter {
- // There was a previous subslice pattern; make sure we don't allow more.
- let rest_span = match pat.kind {
- PatKind::Rest => Some(pat.span),
- PatKind::Ident(.., Some(ref sub)) if sub.is_rest() => {
- // The `HirValidator` is merciless; add a `_` pattern to avoid ICEs.
- after.push(self.pat_wild_with_node_id_of(pat));
- Some(sub.span)
- }
- _ => None,
- };
- if let Some(rest_span) = rest_span {
- // We have e.g., `[a, .., b, ..]`. That's no good, error!
- self.ban_extra_rest_pat(rest_span, prev_rest_span.unwrap(), "slice");
- } else {
- // Lower the pattern normally.
- after.push(self.lower_pat(pat));
- }
- }
-
- hir::PatKind::Slice(
- self.arena.alloc_from_iter(before),
- slice,
- self.arena.alloc_from_iter(after),
- )
- }
-
- fn lower_pat_ident(
- &mut self,
- p: &Pat,
- binding_mode: &BindingMode,
- ident: Ident,
- lower_sub: impl FnOnce(&mut Self) -> Option<&'hir hir::Pat<'hir>>,
- ) -> hir::PatKind<'hir> {
- match self.resolver.get_partial_res(p.id).map(|d| d.base_res()) {
- // `None` can occur in body-less function signatures
- res @ None | res @ Some(Res::Local(_)) => {
- let canonical_id = match res {
- Some(Res::Local(id)) => id,
- _ => p.id,
- };
-
- hir::PatKind::Binding(
- self.lower_binding_mode(binding_mode),
- self.lower_node_id(canonical_id),
- ident,
- lower_sub(self),
- )
- }
- Some(res) => hir::PatKind::Path(hir::QPath::Resolved(
- None,
- self.arena.alloc(hir::Path {
- span: ident.span,
- res: self.lower_res(res),
- segments: arena_vec![self; hir::PathSegment::from_ident(ident)],
- }),
- )),
- }
- }
-
- fn pat_wild_with_node_id_of(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
- self.pat_with_node_id_of(p, hir::PatKind::Wild)
- }
-
- /// Construct a `Pat` with the `HirId` of `p.id` lowered.
- fn pat_with_node_id_of(&mut self, p: &Pat, kind: hir::PatKind<'hir>) -> &'hir hir::Pat<'hir> {
- self.arena.alloc(hir::Pat { hir_id: self.lower_node_id(p.id), kind, span: p.span })
- }
-
- /// Emit a friendly error for extra `..` patterns in a tuple/tuple struct/slice pattern.
- fn ban_extra_rest_pat(&self, sp: Span, prev_sp: Span, ctx: &str) {
- self.diagnostic()
- .struct_span_err(sp, &format!("`..` can only be used once per {} pattern", ctx))
- .span_label(sp, &format!("can only be used once per {} pattern", ctx))
- .span_label(prev_sp, "previously used here")
- .emit();
- }
-
- /// Used to ban the `..` pattern in places it shouldn't be semantically.
- fn ban_illegal_rest_pat(&self, sp: Span) -> hir::PatKind<'hir> {
- self.diagnostic()
- .struct_span_err(sp, "`..` patterns are not allowed here")
- .note("only allowed in tuple, tuple struct, and slice patterns")
- .emit();
-
- // We're not in a list context so `..` can be reasonably treated
- // as `_` because it should always be valid and roughly matches the
- // intent of `..` (notice that the rest of a single slot is that slot).
- hir::PatKind::Wild
- }
-
- fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd {
- match *e {
- RangeEnd::Included(_) => hir::RangeEnd::Included,
- RangeEnd::Excluded => hir::RangeEnd::Excluded,
- }
- }
-
fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst {
self.with_new_scopes(|this| hir::AnonConst {
hir_id: this.lower_node_id(c.id),
}
}
- fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
- match *b {
- BindingMode::ByValue(Mutability::Not) => hir::BindingAnnotation::Unannotated,
- BindingMode::ByRef(Mutability::Not) => hir::BindingAnnotation::Ref,
- BindingMode::ByValue(Mutability::Mut) => hir::BindingAnnotation::Mutable,
- BindingMode::ByRef(Mutability::Mut) => hir::BindingAnnotation::RefMut,
- }
- }
-
fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
match u {
CompilerGenerated => hir::UnsafeSource::CompilerGenerated,
id,
span,
"trait objects without an explicit `dyn` are deprecated",
- builtin::BuiltinLintDiagnostics::BareTraitObject(span, is_global),
+ BuiltinLintDiagnostics::BareTraitObject(span, is_global),
)
}
}
projects / rust.git / blobdiff