use rustc::hir::def::Namespace::{self, *};
use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX};
use rustc::hir::TraitCandidate;
-use rustc::util::nodemap::FxHashMap;
-use rustc_data_structures::fx::FxIndexMap;
+use rustc::util::nodemap::{FxHashMap, FxHashSet};
use smallvec::{smallvec, SmallVec};
use syntax::{unwrap_or, walk_list};
use syntax::ast::*;
}
}
+/// Denotes whether the context for the set of already bound bindings is a `Product`
+/// or `Or` context. This is used in e.g., `fresh_binding` and `resolve_pattern_inner`.
+/// See those functions for more information.
+enum PatBoundCtx {
+ /// A product pattern context, e.g., `Variant(a, b)`.
+ Product,
+ /// An or-pattern context, e.g., `p_0 | ... | p_n`.
+ Or,
+}
+
/// The rib kind restricts certain accesses,
/// e.g. to a `Res::Local` of an outer item.
#[derive(Copy, Clone, Debug)]
ValueNS => "method or associated constant",
MacroNS => bug!("associated macro"),
},
- PathSource::Expr(parent) => match parent.map(|p| &p.node) {
+ PathSource::Expr(parent) => match parent.map(|p| &p.kind) {
// "function" here means "anything callable" rather than `DefKind::Fn`,
// this is not precise but usually more helpful than just "value".
Some(&ExprKind::Call(..)) => "function",
}
fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
- __diagnostic_used!(E0404);
- __diagnostic_used!(E0405);
- __diagnostic_used!(E0412);
- __diagnostic_used!(E0422);
- __diagnostic_used!(E0423);
- __diagnostic_used!(E0425);
- __diagnostic_used!(E0531);
- __diagnostic_used!(E0532);
- __diagnostic_used!(E0573);
- __diagnostic_used!(E0574);
- __diagnostic_used!(E0575);
- __diagnostic_used!(E0576);
+ syntax::diagnostic_used!(E0404);
+ syntax::diagnostic_used!(E0405);
+ syntax::diagnostic_used!(E0412);
+ syntax::diagnostic_used!(E0422);
+ syntax::diagnostic_used!(E0423);
+ syntax::diagnostic_used!(E0425);
+ syntax::diagnostic_used!(E0531);
+ syntax::diagnostic_used!(E0532);
+ syntax::diagnostic_used!(E0573);
+ syntax::diagnostic_used!(E0574);
+ syntax::diagnostic_used!(E0575);
+ syntax::diagnostic_used!(E0576);
match (self, has_unexpected_resolution) {
(PathSource::Trait(_), true) => "E0404",
(PathSource::Trait(_), false) => "E0405",
self.resolve_local(local);
}
fn visit_ty(&mut self, ty: &'tcx Ty) {
- match ty.node {
+ match ty.kind {
TyKind::Path(ref qself, ref path) => {
self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
}
visit::walk_foreign_item(this, foreign_item);
});
}
- fn visit_fn(&mut self, fn_kind: FnKind<'tcx>, declaration: &'tcx FnDecl, _: Span, id: NodeId) {
+ fn visit_fn(&mut self, fn_kind: FnKind<'tcx>, declaration: &'tcx FnDecl, _: Span, _: NodeId) {
debug!("(resolving function) entering function");
let rib_kind = match fn_kind {
FnKind::ItemFn(..) => FnItemRibKind,
// Create a label rib for the function.
this.with_label_rib(rib_kind, |this| {
// Add each argument to the rib.
- this.resolve_params(&declaration.inputs, id);
+ this.resolve_params(&declaration.inputs);
visit::walk_fn_ret_ty(this, &declaration.output);
fn resolve_item(&mut self, item: &Item) {
let name = item.ident.name;
- debug!("(resolving item) resolving {} ({:?})", name, item.node);
+ debug!("(resolving item) resolving {} ({:?})", name, item.kind);
- match item.node {
+ match item.kind {
ItemKind::TyAlias(_, ref generics) |
ItemKind::OpaqueTy(_, ref generics) |
ItemKind::Fn(_, _, ref generics, _) => {
AssocItemRibKind,
);
this.with_generic_param_rib(generic_params, |this| {
- match trait_item.node {
+ match trait_item.kind {
TraitItemKind::Const(ref ty, ref default) => {
this.visit_ty(ty);
) -> T {
let trait_assoc_types = replace(
&mut self.current_trait_assoc_types,
- trait_items.iter().filter_map(|item| match &item.node {
+ trait_items.iter().filter_map(|item| match &item.kind {
TraitItemKind::Type(bounds, _) if bounds.len() == 0 => Some(item.ident),
_ => None,
}).collect(),
AssocItemRibKind);
this.with_generic_param_rib(generic_params, |this| {
use crate::ResolutionError::*;
- match impl_item.node {
+ match impl_item.kind {
ImplItemKind::Const(..) => {
debug!(
"resolve_implementation ImplItemKind::Const",
}
}
- fn resolve_params(&mut self, params: &[Param], id: NodeId) {
- let mut bindings = FxIndexMap::default();
+ fn resolve_params(&mut self, params: &[Param]) {
+ let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
for Param { pat, ty, .. } in params {
- self.resolve_pattern(pat, PatternSource::FnParam, &mut smallvec![id], &mut bindings);
+ self.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
self.visit_ty(ty);
debug!("(resolving function / closure) recorded parameter");
}
self.resolve_pattern_top(&local.pat, PatternSource::Let);
}
- // build a map from pattern identifiers to binding-info's.
- // this is done hygienically. This could arise for a macro
- // that expands into an or-pattern where one 'x' was from the
- // user and one 'x' came from the macro.
+ /// build a map from pattern identifiers to binding-info's.
+ /// this is done hygienically. This could arise for a macro
+ /// that expands into an or-pattern where one 'x' was from the
+ /// user and one 'x' came from the macro.
fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
let mut binding_map = FxHashMap::default();
pat.walk(&mut |pat| {
- if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
- if sub_pat.is_some() || match self.r.partial_res_map.get(&pat.id)
- .map(|res| res.base_res()) {
- Some(Res::Local(..)) => true,
- _ => false,
- } {
- let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
- binding_map.insert(ident, binding_info);
+ match pat.kind {
+ PatKind::Ident(binding_mode, ident, ref sub_pat)
+ if sub_pat.is_some() || self.is_base_res_local(pat.id) =>
+ {
+ binding_map.insert(ident, BindingInfo { span: ident.span, binding_mode });
+ }
+ PatKind::Or(ref ps) => {
+ // Check the consistency of this or-pattern and
+ // then add all bindings to the larger map.
+ for bm in self.check_consistent_bindings(ps) {
+ binding_map.extend(bm);
+ }
+ return false;
}
+ _ => {}
}
+
true
});
binding_map
}
- // 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>]) {
+ fn is_base_res_local(&self, nid: NodeId) -> bool {
+ match self.r.partial_res_map.get(&nid).map(|res| res.base_res()) {
+ Some(Res::Local(..)) => true,
+ _ => false,
+ }
+ }
+
+ /// 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>]) -> Vec<BindingMap> {
let mut missing_vars = FxHashMap::default();
let mut inconsistent_vars = FxHashMap::default();
- 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));
- }
+ // 1) Compute the binding maps of all arms.
+ let maps = pats.iter()
+ .map(|pat| self.binding_mode_map(pat))
+ .collect::<Vec<_>>();
+
+ // 2) Record any missing bindings or binding mode inconsistencies.
+ for (map_outer, pat_outer) in pats.iter().enumerate().map(|(idx, pat)| (&maps[idx], pat)) {
+ // Check against all arms except for the same pattern which is always self-consistent.
+ let inners = pats.iter().enumerate()
+ .filter(|(_, pat)| pat.id != pat_outer.id)
+ .flat_map(|(idx, _)| maps[idx].iter())
+ .map(|(key, binding)| (key.name, map_outer.get(&key), binding));
+
+ for (name, info, &binding_inner) in inners {
+ match info {
+ None => { // The inner binding is missing in the outer.
+ let binding_error = missing_vars
+ .entry(name)
+ .or_insert_with(|| BindingError {
+ name,
+ origin: BTreeSet::new(),
+ target: BTreeSet::new(),
+ could_be_path: 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) => {
+ if binding_outer.binding_mode != binding_inner.binding_mode {
+ // The binding modes in the outer and inner bindings differ.
+ inconsistent_vars
+ .entry(name)
+ .or_insert((binding_inner.span, binding_outer.span));
}
}
}
}
}
+ // 3) Report all missing variables we found.
let mut missing_vars = missing_vars.iter_mut().collect::<Vec<_>>();
missing_vars.sort();
for (name, mut v) in missing_vars {
ResolutionError::VariableNotBoundInPattern(v));
}
+ // 4) Report all inconsistencies in binding modes we found.
let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
inconsistent_vars.sort();
for (name, v) in inconsistent_vars {
self.r.report_error(v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
}
+
+ // 5) Finally bubble up all the binding maps.
+ maps
+ }
+
+ /// Check the consistency of the outermost or-patterns.
+ fn check_consistent_bindings_top(&mut self, pat: &Pat) {
+ pat.walk(&mut |pat| match pat.kind {
+ PatKind::Or(ref ps) => {
+ self.check_consistent_bindings(ps);
+ false
+ },
+ _ => true,
+ })
}
fn resolve_arm(&mut self, arm: &Arm) {
self.with_rib(ValueNS, NormalRibKind, |this| {
- this.resolve_pats(&arm.pats, PatternSource::Match);
+ this.resolve_pattern_top(&arm.pat, PatternSource::Match);
walk_list!(this, visit_expr, &arm.guard);
this.visit_expr(&arm.body);
});
}
- /// Arising from `source`, resolve a sequence of patterns (top level or-patterns).
- fn resolve_pats(&mut self, pats: &[P<Pat>], source: PatternSource) {
- let mut bindings_list = FxIndexMap::default();
- for pat in pats {
- self.resolve_pattern(pat, source, &mut smallvec![pat.id], &mut bindings_list);
- }
- // This has to happen *after* we determine which pat_idents are variants
- if pats.len() > 1 {
- self.check_consistent_bindings(pats);
- }
- }
-
+ /// Arising from `source`, resolve a top level pattern.
fn resolve_pattern_top(&mut self, pat: &Pat, pat_src: PatternSource) {
- self.resolve_pattern(pat, pat_src, &mut smallvec![pat.id], &mut FxIndexMap::default());
+ let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
+ self.resolve_pattern(pat, pat_src, &mut bindings);
}
fn resolve_pattern(
&mut self,
pat: &Pat,
pat_src: PatternSource,
- prod_ids: &mut SmallVec<[NodeId; 1]>,
- bindings: &mut FxIndexMap<Ident, NodeId>,
+ bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
) {
- self.resolve_pattern_inner(pat, pat_src, prod_ids, bindings);
+ self.resolve_pattern_inner(pat, pat_src, bindings);
+ // This has to happen *after* we determine which pat_idents are variants:
+ self.check_consistent_bindings_top(pat);
visit::walk_pat(self, pat);
}
+ /// Resolve bindings in a pattern. This is a helper to `resolve_pattern`.
+ ///
+ /// ### `bindings`
+ ///
+ /// A stack of sets of bindings accumulated.
+ ///
+ /// In each set, `PatBoundCtx::Product` denotes that a found binding in it should
+ /// be interpreted as re-binding an already bound binding. This results in an error.
+ /// Meanwhile, `PatBound::Or` denotes that a found binding in the set should result
+ /// in reusing this binding rather than creating a fresh one.
+ ///
+ /// When called at the top level, the stack must have a single element
+ /// with `PatBound::Product`. Otherwise, pushing to the stack happens as
+ /// or-patterns (`p_0 | ... | p_n`) are encountered and the context needs
+ /// to be switched to `PatBoundCtx::Or` and then `PatBoundCtx::Product` for each `p_i`.
+ /// When each `p_i` has been dealt with, the top set is merged with its parent.
+ /// When a whole or-pattern has been dealt with, the thing happens.
+ ///
+ /// See the implementation and `fresh_binding` for more details.
fn resolve_pattern_inner(
&mut self,
pat: &Pat,
pat_src: PatternSource,
- prod_ids: &mut SmallVec<[NodeId; 1]>,
- bindings: &mut FxIndexMap<Ident, NodeId>,
+ bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
) {
// Visit all direct subpatterns of this pattern.
pat.walk(&mut |pat| {
- debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
- match pat.node {
+ debug!("resolve_pattern pat={:?} node={:?}", pat, pat.kind);
+ match pat.kind {
PatKind::Ident(bmode, ident, ref sub) => {
// First try to resolve the identifier as some existing entity,
// then fall back to a fresh binding.
let has_sub = sub.is_some();
let res = self.try_resolve_as_non_binding(pat_src, pat, bmode, ident, has_sub)
- .unwrap_or_else(|| {
- self.fresh_binding(ident, pat.id, pat_src, prod_ids, bindings)
- });
+ .unwrap_or_else(|| self.fresh_binding(ident, pat.id, pat_src, bindings));
self.r.record_partial_res(pat.id, PartialRes::new(res));
}
PatKind::TupleStruct(ref path, ..) => {
self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
}
PatKind::Or(ref ps) => {
- let len_before = bindings.len();
+ // Add a new set of bindings to the stack. `Or` here records that when a
+ // binding already exists in this set, it should not result in an error because
+ // `V1(a) | V2(a)` must be allowed and are checked for consistency later.
+ bindings.push((PatBoundCtx::Or, Default::default()));
for p in ps {
- // We need to change `prod_ids.last()` at this point so that overlapping
- // bindings across the summands in the or-pattern do not result in an error.
- // The idea is that in `V1(a) | V2(a)`, the `a` in `V1` will be inserted
- // with a different id than the one in `V2`. As a result, `V1(a) | V2(a)`
- // compiles as it should. We will later check or-patterns for consistency.
- prod_ids.push(p.id);
- self.resolve_pattern_inner(p, pat_src, prod_ids, bindings);
- prod_ids.pop();
+ // Now we need to switch back to a product context so that each
+ // part of the or-pattern internally rejects already bound names.
+ // For example, `V1(a) | V2(a, a)` and `V1(a, a) | V2(a)` are bad.
+ bindings.push((PatBoundCtx::Product, Default::default()));
+ self.resolve_pattern_inner(p, pat_src, bindings);
+ // Move up the non-overlapping bindings to the or-pattern.
+ // Existing bindings just get "merged".
+ let collected = bindings.pop().unwrap().1;
+ bindings.last_mut().unwrap().1.extend(collected);
}
-
- // We've rejected overlap in each product in the sum.
- // Now we must account for the possibility that the or-pattern is a factor
- // in a product. A basic case to reject here is `(V1(a) | V2(a), a)`.
- let last_id = *prod_ids.last().unwrap();
- bindings.values_mut().skip(len_before).for_each(|val| *val = last_id);
+ // This or-pattern itself can itself be part of a product,
+ // e.g. `(V1(a) | V2(a), a)` or `(a, V1(a) | V2(a))`.
+ // Both cases bind `a` again in a product pattern and must be rejected.
+ let collected = bindings.pop().unwrap().1;
+ bindings.last_mut().unwrap().1.extend(collected);
// Prevent visiting `ps` as we've already done so above.
return false;
ident: Ident,
pat_id: NodeId,
pat_src: PatternSource,
- prod_ids: &[NodeId],
- bindings: &mut FxIndexMap<Ident, NodeId>,
+ bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
) -> Res {
// Add the binding to the local ribs, if it doesn't already exist in the bindings map.
// (We must not add it if it's in the bindings map because that breaks the assumptions
// later passes make about or-patterns.)
let ident = ident.modern_and_legacy();
- let res = Res::Local(pat_id);
- match bindings.get(&ident).cloned() {
- Some(id) if prod_ids.contains(&id) => {
- // We have some overlap in a product pattern, e.g. `(a, a)` which is not allowed.
- use ResolutionError::*;
- let error = match pat_src {
- // `fn f(a: u8, a: u8)`:
- PatternSource::FnParam => IdentifierBoundMoreThanOnceInParameterList,
- // `Variant(a, a)`:
- _ => IdentifierBoundMoreThanOnceInSamePattern,
- };
- self.r.report_error(ident.span, error(&ident.as_str()));
- }
- Some(..) => {
- // `Variant1(a) | Variant2(a)`, ok
- // Reuse definition from the first `a`.
- return self.innermost_rib_bindings(ValueNS)[&ident];
+
+ // Walk outwards the stack of products / or-patterns and
+ // find out if the identifier has been bound in any of these.
+ let mut already_bound_and = false;
+ let mut already_bound_or = false;
+ for (is_sum, set) in bindings.iter_mut().rev() {
+ match (is_sum, set.get(&ident).cloned()) {
+ // Already bound in a product pattern, e.g. `(a, a)` which is not allowed.
+ (PatBoundCtx::Product, Some(..)) => already_bound_and = true,
+ // Already bound in an or-pattern, e.g. `V1(a) | V2(a)`.
+ // This is *required* for consistency which is checked later.
+ (PatBoundCtx::Or, Some(..)) => already_bound_or = true,
+ // Not already bound here.
+ _ => {}
}
- // A completely fresh binding, add to the lists if it's valid.
- None if ident.name != kw::Invalid => {
- bindings.insert(ident, *prod_ids.last().unwrap());
+ }
+
+ if already_bound_and {
+ // Overlap in a product pattern somewhere; report an error.
+ use ResolutionError::*;
+ let error = match pat_src {
+ // `fn f(a: u8, a: u8)`:
+ PatternSource::FnParam => IdentifierBoundMoreThanOnceInParameterList,
+ // `Variant(a, a)`:
+ _ => IdentifierBoundMoreThanOnceInSamePattern,
+ };
+ self.r.report_error(ident.span, error(&ident.as_str()));
+ }
+
+ // Record as bound if it's valid:
+ let ident_valid = ident.name != kw::Invalid;
+ if ident_valid {
+ bindings.last_mut().unwrap().1.insert(ident);
+ }
+
+ if already_bound_or {
+ // `Variant1(a) | Variant2(a)`, ok
+ // Reuse definition from the first `a`.
+ self.innermost_rib_bindings(ValueNS)[&ident]
+ } else {
+ let res = Res::Local(pat_id);
+ if ident_valid {
+ // A completely fresh binding add to the set if it's valid.
self.innermost_rib_bindings(ValueNS).insert(ident, res);
}
- None => {}
+ res
}
-
- res
}
fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut IdentMap<Res> {
// Descend into the block.
for stmt in &block.stmts {
- if let StmtKind::Item(ref item) = stmt.node {
- if let ItemKind::MacroDef(..) = item.node {
+ if let StmtKind::Item(ref item) = stmt.kind {
+ if let ItemKind::MacroDef(..) = item.kind {
num_macro_definition_ribs += 1;
let res = self.r.definitions.local_def_id(item.id);
self.ribs[ValueNS].push(Rib::new(MacroDefinition(res)));
self.record_candidate_traits_for_expr_if_necessary(expr);
// Next, resolve the node.
- match expr.node {
+ match expr.kind {
ExprKind::Path(ref qself, ref path) => {
self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
visit::walk_expr(self, expr);
visit::walk_expr(self, expr);
}
- ExprKind::Let(ref pats, ref scrutinee) => {
+ ExprKind::Let(ref pat, ref scrutinee) => {
self.visit_expr(scrutinee);
- self.resolve_pats(pats, PatternSource::Let);
+ self.resolve_pattern_top(pat, PatternSource::Let);
}
ExprKind::If(ref cond, ref then, ref opt_else) => {
ExprKind::Closure(_, IsAsync::Async { .. }, _, ref fn_decl, ref body, _span) => {
self.with_rib(ValueNS, NormalRibKind, |this| {
// Resolve arguments:
- this.resolve_params(&fn_decl.inputs, expr.id);
+ this.resolve_params(&fn_decl.inputs);
// No need to resolve return type --
// the outer closure return type is `FunctionRetTy::Default`.
}
fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
- match expr.node {
+ match expr.kind {
ExprKind::Field(_, ident) => {
// FIXME(#6890): Even though you can't treat a method like a
// field, we need to add any trait methods we find that match
projects / rust.git / blobdiff