1 //! "Late resolution" is the pass that resolves most of names in a crate beside imports and macros.
2 //! It runs when the crate is fully expanded and its module structure is fully built.
3 //! So it just walks through the crate and resolves all the expressions, types, etc.
5 //! If you wonder why there's no `early.rs`, that's because it's split into three files -
6 //! `build_reduced_graph.rs`, `macros.rs` and `imports.rs`.
10 use crate::{path_names_to_string, BindingError, Finalize, LexicalScopeBinding};
11 use crate::{Module, ModuleOrUniformRoot, NameBinding, ParentScope, PathResult};
12 use crate::{ResolutionError, Resolver, Segment, UseError};
14 use rustc_ast::ptr::P;
15 use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
17 use rustc_ast_lowering::ResolverAstLowering;
18 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
19 use rustc_errors::DiagnosticId;
20 use rustc_hir::def::Namespace::{self, *};
21 use rustc_hir::def::{self, CtorKind, DefKind, PartialRes, PerNS};
22 use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
23 use rustc_hir::{PrimTy, TraitCandidate};
24 use rustc_middle::ty::DefIdTree;
25 use rustc_middle::{bug, span_bug};
26 use rustc_session::lint;
27 use rustc_span::symbol::{kw, sym, Ident, Symbol};
28 use rustc_span::{BytePos, Span};
29 use smallvec::{smallvec, SmallVec};
31 use rustc_span::source_map::{respan, Spanned};
32 use std::collections::{hash_map::Entry, BTreeSet};
33 use std::mem::{replace, take};
39 type Res = def::Res<NodeId>;
41 type IdentMap<T> = FxHashMap<Ident, T>;
43 /// Map from the name in a pattern to its binding mode.
44 type BindingMap = IdentMap<BindingInfo>;
46 #[derive(Copy, Clone, Debug)]
49 binding_mode: BindingMode,
52 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
60 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
67 fn descr(self) -> &'static str {
69 PatternSource::Match => "match binding",
70 PatternSource::Let => "let binding",
71 PatternSource::For => "for binding",
72 PatternSource::FnParam => "function parameter",
77 /// Denotes whether the context for the set of already bound bindings is a `Product`
78 /// or `Or` context. This is used in e.g., `fresh_binding` and `resolve_pattern_inner`.
79 /// See those functions for more information.
82 /// A product pattern context, e.g., `Variant(a, b)`.
84 /// An or-pattern context, e.g., `p_0 | ... | p_n`.
88 /// Does this the item (from the item rib scope) allow generic parameters?
89 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
90 crate enum HasGenericParams {
95 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
96 crate enum ConstantItemKind {
101 /// The rib kind restricts certain accesses,
102 /// e.g. to a `Res::Local` of an outer item.
103 #[derive(Copy, Clone, Debug)]
104 crate enum RibKind<'a> {
105 /// No restriction needs to be applied.
108 /// We passed through an impl or trait and are now in one of its
109 /// methods or associated types. Allow references to ty params that impl or trait
110 /// binds. Disallow any other upvars (including other ty params that are
114 /// We passed through a closure. Disallow labels.
115 ClosureOrAsyncRibKind,
117 /// We passed through a function definition. Disallow upvars.
118 /// Permit only those const parameters that are specified in the function's generics.
121 /// We passed through an item scope. Disallow upvars.
122 ItemRibKind(HasGenericParams),
124 /// We're in a constant item. Can't refer to dynamic stuff.
126 /// The `bool` indicates if this constant may reference generic parameters
127 /// and is used to only allow generic parameters to be used in trivial constant expressions.
128 ConstantItemRibKind(bool, Option<(Ident, ConstantItemKind)>),
130 /// We passed through a module.
131 ModuleRibKind(Module<'a>),
133 /// We passed through a `macro_rules!` statement
134 MacroDefinition(DefId),
136 /// All bindings in this rib are generic parameters that can't be used
137 /// from the default of a generic parameter because they're not declared
138 /// before said generic parameter. Also see the `visit_generics` override.
139 ForwardGenericParamBanRibKind,
141 /// We are inside of the type of a const parameter. Can't refer to any
145 /// We are inside a `sym` inline assembly operand. Can only refer to
151 /// Whether this rib kind contains generic parameters, as opposed to local
153 crate fn contains_params(&self) -> bool {
156 | ClosureOrAsyncRibKind
158 | ConstantItemRibKind(..)
161 | ConstParamTyRibKind
162 | InlineAsmSymRibKind => false,
163 AssocItemRibKind | ItemRibKind(_) | ForwardGenericParamBanRibKind => true,
168 /// A single local scope.
170 /// A rib represents a scope names can live in. Note that these appear in many places, not just
171 /// around braces. At any place where the list of accessible names (of the given namespace)
172 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
173 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
176 /// Different [rib kinds](enum.RibKind) are transparent for different names.
178 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
179 /// resolving, the name is looked up from inside out.
181 crate struct Rib<'a, R = Res> {
182 pub bindings: IdentMap<R>,
183 pub kind: RibKind<'a>,
186 impl<'a, R> Rib<'a, R> {
187 fn new(kind: RibKind<'a>) -> Rib<'a, R> {
188 Rib { bindings: Default::default(), kind }
192 #[derive(Copy, Clone, Debug)]
193 enum LifetimeRibKind {
194 /// This rib acts as a barrier to forbid reference to lifetimes of a parent item.
197 /// This rib declares generic parameters.
198 Generics { span: Span, kind: LifetimeBinderKind },
200 /// For **Modern** cases, create a new anonymous region parameter
201 /// and reference that.
203 /// For **Dyn Bound** cases, pass responsibility to
204 /// `resolve_lifetime` code.
206 /// For **Deprecated** cases, report an error.
207 AnonymousCreateParameter,
209 /// Give a hard error when either `&` or `'_` is written. Used to
210 /// rule out things like `where T: Foo<'_>`. Does not imply an
211 /// error on default object bounds (e.g., `Box<dyn Foo>`).
212 AnonymousReportError,
214 /// Pass responsibility to `resolve_lifetime` code for all cases.
215 AnonymousPassThrough,
218 #[derive(Copy, Clone, Debug)]
219 enum LifetimeBinderKind {
228 impl LifetimeBinderKind {
229 fn descr(self) -> &'static str {
230 use LifetimeBinderKind::*;
232 BareFnType => "type",
233 PolyTrait => "bound",
234 WhereBound => "bound",
236 ImplBlock => "impl block",
237 Function => "function",
244 kind: LifetimeRibKind,
245 bindings: IdentMap<()>,
249 fn new(kind: LifetimeRibKind) -> LifetimeRib {
250 LifetimeRib { bindings: Default::default(), kind }
254 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
255 crate enum AliasPossibility {
260 #[derive(Copy, Clone, Debug)]
261 crate enum PathSource<'a> {
262 // Type paths `Path`.
264 // Trait paths in bounds or impls.
265 Trait(AliasPossibility),
266 // Expression paths `path`, with optional parent context.
267 Expr(Option<&'a Expr>),
268 // Paths in path patterns `Path`.
270 // Paths in struct expressions and patterns `Path { .. }`.
272 // Paths in tuple struct patterns `Path(..)`.
273 TupleStruct(Span, &'a [Span]),
274 // `m::A::B` in `<T as m::A>::B::C`.
275 TraitItem(Namespace),
278 impl<'a> PathSource<'a> {
279 fn namespace(self) -> Namespace {
281 PathSource::Type | PathSource::Trait(_) | PathSource::Struct => TypeNS,
282 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct(..) => ValueNS,
283 PathSource::TraitItem(ns) => ns,
287 fn defer_to_typeck(self) -> bool {
290 | PathSource::Expr(..)
293 | PathSource::TupleStruct(..) => true,
294 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
298 fn descr_expected(self) -> &'static str {
300 PathSource::Type => "type",
301 PathSource::Trait(_) => "trait",
302 PathSource::Pat => "unit struct, unit variant or constant",
303 PathSource::Struct => "struct, variant or union type",
304 PathSource::TupleStruct(..) => "tuple struct or tuple variant",
305 PathSource::TraitItem(ns) => match ns {
306 TypeNS => "associated type",
307 ValueNS => "method or associated constant",
308 MacroNS => bug!("associated macro"),
310 PathSource::Expr(parent) => match parent.as_ref().map(|p| &p.kind) {
311 // "function" here means "anything callable" rather than `DefKind::Fn`,
312 // this is not precise but usually more helpful than just "value".
313 Some(ExprKind::Call(call_expr, _)) => match &call_expr.kind {
314 // the case of `::some_crate()`
315 ExprKind::Path(_, path)
316 if path.segments.len() == 2
317 && path.segments[0].ident.name == kw::PathRoot =>
321 ExprKind::Path(_, path) => {
322 let mut msg = "function";
323 if let Some(segment) = path.segments.iter().last() {
324 if let Some(c) = segment.ident.to_string().chars().next() {
325 if c.is_uppercase() {
326 msg = "function, tuple struct or tuple variant";
339 fn is_call(self) -> bool {
340 matches!(self, PathSource::Expr(Some(&Expr { kind: ExprKind::Call(..), .. })))
343 crate fn is_expected(self, res: Res) -> bool {
345 PathSource::Type => matches!(
352 | DefKind::TraitAlias
357 | DefKind::ForeignTy,
362 PathSource::Trait(AliasPossibility::No) => matches!(res, Res::Def(DefKind::Trait, _)),
363 PathSource::Trait(AliasPossibility::Maybe) => {
364 matches!(res, Res::Def(DefKind::Trait | DefKind::TraitAlias, _))
366 PathSource::Expr(..) => matches!(
369 DefKind::Ctor(_, CtorKind::Const | CtorKind::Fn)
374 | DefKind::AssocConst
375 | DefKind::ConstParam,
380 PathSource::Pat => matches!(
383 DefKind::Ctor(_, CtorKind::Const) | DefKind::Const | DefKind::AssocConst,
385 ) | Res::SelfCtor(..)
387 PathSource::TupleStruct(..) => res.expected_in_tuple_struct_pat(),
388 PathSource::Struct => matches!(
397 ) | Res::SelfTy { .. }
399 PathSource::TraitItem(ns) => match res {
400 Res::Def(DefKind::AssocConst | DefKind::AssocFn, _) if ns == ValueNS => true,
401 Res::Def(DefKind::AssocTy, _) if ns == TypeNS => true,
407 fn error_code(self, has_unexpected_resolution: bool) -> DiagnosticId {
408 use rustc_errors::error_code;
409 match (self, has_unexpected_resolution) {
410 (PathSource::Trait(_), true) => error_code!(E0404),
411 (PathSource::Trait(_), false) => error_code!(E0405),
412 (PathSource::Type, true) => error_code!(E0573),
413 (PathSource::Type, false) => error_code!(E0412),
414 (PathSource::Struct, true) => error_code!(E0574),
415 (PathSource::Struct, false) => error_code!(E0422),
416 (PathSource::Expr(..), true) => error_code!(E0423),
417 (PathSource::Expr(..), false) => error_code!(E0425),
418 (PathSource::Pat | PathSource::TupleStruct(..), true) => error_code!(E0532),
419 (PathSource::Pat | PathSource::TupleStruct(..), false) => error_code!(E0531),
420 (PathSource::TraitItem(..), true) => error_code!(E0575),
421 (PathSource::TraitItem(..), false) => error_code!(E0576),
427 struct DiagnosticMetadata<'ast> {
428 /// The current trait's associated items' ident, used for diagnostic suggestions.
429 current_trait_assoc_items: Option<&'ast [P<AssocItem>]>,
431 /// The current self type if inside an impl (used for better errors).
432 current_self_type: Option<Ty>,
434 /// The current self item if inside an ADT (used for better errors).
435 current_self_item: Option<NodeId>,
437 /// The current trait (used to suggest).
438 current_item: Option<&'ast Item>,
440 /// When processing generics and encountering a type not found, suggest introducing a type
442 currently_processing_generics: bool,
444 /// The current enclosing (non-closure) function (used for better errors).
445 current_function: Option<(FnKind<'ast>, Span)>,
447 /// A list of labels as of yet unused. Labels will be removed from this map when
448 /// they are used (in a `break` or `continue` statement)
449 unused_labels: FxHashMap<NodeId, Span>,
451 /// Only used for better errors on `fn(): fn()`.
452 current_type_ascription: Vec<Span>,
454 /// Only used for better errors on `let x = { foo: bar };`.
455 /// In the case of a parse error with `let x = { foo: bar, };`, this isn't needed, it's only
456 /// needed for cases where this parses as a correct type ascription.
457 current_block_could_be_bare_struct_literal: Option<Span>,
459 /// Only used for better errors on `let <pat>: <expr, not type>;`.
460 current_let_binding: Option<(Span, Option<Span>, Option<Span>)>,
462 /// Used to detect possible `if let` written without `let` and to provide structured suggestion.
463 in_if_condition: Option<&'ast Expr>,
465 /// If we are currently in a trait object definition. Used to point at the bounds when
466 /// encountering a struct or enum.
467 current_trait_object: Option<&'ast [ast::GenericBound]>,
469 /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
470 current_where_predicate: Option<&'ast WherePredicate>,
472 current_type_path: Option<&'ast Ty>,
475 struct LateResolutionVisitor<'a, 'b, 'ast> {
476 r: &'b mut Resolver<'a>,
478 /// The module that represents the current item scope.
479 parent_scope: ParentScope<'a>,
481 /// The current set of local scopes for types and values.
482 /// FIXME #4948: Reuse ribs to avoid allocation.
483 ribs: PerNS<Vec<Rib<'a>>>,
485 /// The current set of local scopes, for labels.
486 label_ribs: Vec<Rib<'a, NodeId>>,
488 /// The current set of local scopes for lifetimes.
489 lifetime_ribs: Vec<LifetimeRib>,
491 /// The trait that the current context can refer to.
492 current_trait_ref: Option<(Module<'a>, TraitRef)>,
494 /// Fields used to add information to diagnostic errors.
495 diagnostic_metadata: DiagnosticMetadata<'ast>,
497 /// State used to know whether to ignore resolution errors for function bodies.
499 /// In particular, rustdoc uses this to avoid giving errors for `cfg()` items.
500 /// In most cases this will be `None`, in which case errors will always be reported.
501 /// If it is `true`, then it will be updated when entering a nested function or trait body.
505 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
506 impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
507 fn visit_attribute(&mut self, _: &'ast Attribute) {
508 // We do not want to resolve expressions that appear in attributes,
509 // as they do not correspond to actual code.
511 fn visit_item(&mut self, item: &'ast Item) {
512 let prev = replace(&mut self.diagnostic_metadata.current_item, Some(item));
513 // Always report errors in items we just entered.
514 let old_ignore = replace(&mut self.in_func_body, false);
515 self.with_lifetime_rib(LifetimeRibKind::Item, |this| this.resolve_item(item));
516 self.in_func_body = old_ignore;
517 self.diagnostic_metadata.current_item = prev;
519 fn visit_arm(&mut self, arm: &'ast Arm) {
520 self.resolve_arm(arm);
522 fn visit_block(&mut self, block: &'ast Block) {
523 self.resolve_block(block);
525 fn visit_anon_const(&mut self, constant: &'ast AnonConst) {
526 // We deal with repeat expressions explicitly in `resolve_expr`.
527 self.resolve_anon_const(constant, IsRepeatExpr::No);
529 fn visit_expr(&mut self, expr: &'ast Expr) {
530 self.resolve_expr(expr, None);
532 fn visit_local(&mut self, local: &'ast Local) {
533 let local_spans = match local.pat.kind {
534 // We check for this to avoid tuple struct fields.
535 PatKind::Wild => None,
538 local.ty.as_ref().map(|ty| ty.span),
539 local.kind.init().map(|init| init.span),
542 let original = replace(&mut self.diagnostic_metadata.current_let_binding, local_spans);
543 self.resolve_local(local);
544 self.diagnostic_metadata.current_let_binding = original;
546 fn visit_ty(&mut self, ty: &'ast Ty) {
547 let prev = self.diagnostic_metadata.current_trait_object;
548 let prev_ty = self.diagnostic_metadata.current_type_path;
550 TyKind::Rptr(None, _) => {
551 // Elided lifetime in reference: we resolve as if there was some lifetime `'_` with
553 let span = self.r.session.source_map().next_point(ty.span.shrink_to_lo());
554 self.resolve_elided_lifetime(ty.id, span);
556 TyKind::Path(ref qself, ref path) => {
557 self.diagnostic_metadata.current_type_path = Some(ty);
558 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
560 TyKind::ImplicitSelf => {
561 let self_ty = Ident::with_dummy_span(kw::SelfUpper);
563 .resolve_ident_in_lexical_scope(
566 Finalize::SimplePath(ty.id, ty.span),
569 .map_or(Res::Err, |d| d.res());
570 self.r.record_partial_res(ty.id, PartialRes::new(res));
572 TyKind::TraitObject(ref bounds, ..) => {
573 self.diagnostic_metadata.current_trait_object = Some(&bounds[..]);
575 TyKind::BareFn(ref bare_fn) => {
576 let span = if bare_fn.generic_params.is_empty() {
577 ty.span.shrink_to_lo()
581 self.with_generic_param_rib(
582 &bare_fn.generic_params,
584 LifetimeRibKind::Generics { kind: LifetimeBinderKind::BareFnType, span },
586 this.with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough, |this| {
587 this.visit_generic_param_vec(&bare_fn.generic_params, false);
588 visit::walk_fn_decl(this, &bare_fn.decl);
592 self.diagnostic_metadata.current_trait_object = prev;
597 visit::walk_ty(self, ty);
598 self.diagnostic_metadata.current_trait_object = prev;
599 self.diagnostic_metadata.current_type_path = prev_ty;
601 fn visit_poly_trait_ref(&mut self, tref: &'ast PolyTraitRef, _: &'ast TraitBoundModifier) {
603 if tref.bound_generic_params.is_empty() { tref.span.shrink_to_lo() } else { tref.span };
604 self.with_generic_param_rib(
605 &tref.bound_generic_params,
607 LifetimeRibKind::Generics { kind: LifetimeBinderKind::PolyTrait, span },
609 this.visit_generic_param_vec(&tref.bound_generic_params, false);
610 this.smart_resolve_path(
611 tref.trait_ref.ref_id,
613 &tref.trait_ref.path,
614 PathSource::Trait(AliasPossibility::Maybe),
616 this.visit_trait_ref(&tref.trait_ref);
620 fn visit_foreign_item(&mut self, foreign_item: &'ast ForeignItem) {
621 match foreign_item.kind {
622 ForeignItemKind::TyAlias(box TyAlias { ref generics, .. }) => {
623 self.with_lifetime_rib(LifetimeRibKind::Item, |this| {
624 this.with_generic_param_rib(
626 ItemRibKind(HasGenericParams::Yes),
627 LifetimeRibKind::Generics {
628 kind: LifetimeBinderKind::Item,
631 |this| visit::walk_foreign_item(this, foreign_item),
635 ForeignItemKind::Fn(box Fn { ref generics, .. }) => {
636 self.with_lifetime_rib(LifetimeRibKind::Item, |this| {
637 this.with_generic_param_rib(
639 ItemRibKind(HasGenericParams::Yes),
640 LifetimeRibKind::Generics {
641 kind: LifetimeBinderKind::Function,
644 |this| visit::walk_foreign_item(this, foreign_item),
648 ForeignItemKind::Static(..) => {
649 self.with_item_rib(|this| {
650 visit::walk_foreign_item(this, foreign_item);
653 ForeignItemKind::MacCall(..) => {
654 panic!("unexpanded macro in resolve!")
658 fn visit_fn(&mut self, fn_kind: FnKind<'ast>, sp: Span, _: NodeId) {
659 let rib_kind = match fn_kind {
660 // Bail if the function is foreign, and thus cannot validly have
661 // a body, or if there's no body for some other reason.
662 FnKind::Fn(FnCtxt::Foreign, _, sig, _, generics, _)
663 | FnKind::Fn(_, _, sig, _, generics, None) => {
664 self.with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough, |this| {
665 // We don't need to deal with patterns in parameters, because
666 // they are not possible for foreign or bodiless functions.
667 this.visit_fn_header(&sig.header);
668 this.visit_generics(generics);
669 visit::walk_fn_decl(this, &sig.decl);
673 FnKind::Fn(FnCtxt::Free, ..) => FnItemRibKind,
674 FnKind::Fn(FnCtxt::Assoc(_), ..) => NormalRibKind,
675 FnKind::Closure(..) => ClosureOrAsyncRibKind,
677 let previous_value = self.diagnostic_metadata.current_function;
678 if matches!(fn_kind, FnKind::Fn(..)) {
679 self.diagnostic_metadata.current_function = Some((fn_kind, sp));
681 debug!("(resolving function) entering function");
682 let declaration = fn_kind.decl();
684 // Create a value rib for the function.
685 self.with_rib(ValueNS, rib_kind, |this| {
686 // Create a label rib for the function.
687 this.with_label_rib(rib_kind, |this| {
688 let async_node_id = fn_kind.header().and_then(|h| h.asyncness.opt_return_id());
690 if let FnKind::Fn(_, _, _, _, generics, _) = fn_kind {
691 this.visit_generics(generics);
694 if async_node_id.is_some() {
695 // In `async fn`, argument-position elided lifetimes
696 // must be transformed into fresh generic parameters so that
697 // they can be applied to the opaque `impl Trait` return type.
698 this.with_lifetime_rib(LifetimeRibKind::AnonymousCreateParameter, |this| {
699 // Add each argument to the rib.
700 this.resolve_params(&declaration.inputs)
703 this.with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough, |this| {
704 visit::walk_fn_ret_ty(this, &declaration.output)
707 this.with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough, |this| {
708 // Add each argument to the rib.
709 this.resolve_params(&declaration.inputs);
711 visit::walk_fn_ret_ty(this, &declaration.output);
715 // Ignore errors in function bodies if this is rustdoc
716 // Be sure not to set this until the function signature has been resolved.
717 let previous_state = replace(&mut this.in_func_body, true);
718 // Resolve the function body, potentially inside the body of an async closure
719 this.with_lifetime_rib(
720 LifetimeRibKind::AnonymousPassThrough,
721 |this| match fn_kind {
722 FnKind::Fn(.., body) => walk_list!(this, visit_block, body),
723 FnKind::Closure(_, body) => this.visit_expr(body),
727 debug!("(resolving function) leaving function");
728 this.in_func_body = previous_state;
731 self.diagnostic_metadata.current_function = previous_value;
733 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
734 self.resolve_lifetime(lifetime)
737 fn visit_generics(&mut self, generics: &'ast Generics) {
738 self.visit_generic_param_vec(
740 self.diagnostic_metadata.current_self_item.is_some(),
742 for p in &generics.where_clause.predicates {
743 self.visit_where_predicate(p);
747 fn visit_generic_arg(&mut self, arg: &'ast GenericArg) {
748 debug!("visit_generic_arg({:?})", arg);
749 let prev = replace(&mut self.diagnostic_metadata.currently_processing_generics, true);
751 GenericArg::Type(ref ty) => {
752 // We parse const arguments as path types as we cannot distinguish them during
753 // parsing. We try to resolve that ambiguity by attempting resolution the type
754 // namespace first, and if that fails we try again in the value namespace. If
755 // resolution in the value namespace succeeds, we have an generic const argument on
757 if let TyKind::Path(ref qself, ref path) = ty.kind {
758 // We cannot disambiguate multi-segment paths right now as that requires type
760 if path.segments.len() == 1 && path.segments[0].args.is_none() {
761 let mut check_ns = |ns| {
762 self.maybe_resolve_ident_in_lexical_scope(path.segments[0].ident, ns)
765 if !check_ns(TypeNS) && check_ns(ValueNS) {
766 // This must be equivalent to `visit_anon_const`, but we cannot call it
767 // directly due to visitor lifetimes so we have to copy-paste some code.
769 // Note that we might not be inside of an repeat expression here,
770 // but considering that `IsRepeatExpr` is only relevant for
771 // non-trivial constants this is doesn't matter.
772 self.with_constant_rib(IsRepeatExpr::No, true, None, |this| {
773 this.smart_resolve_path(
777 PathSource::Expr(None),
780 if let Some(ref qself) = *qself {
781 this.visit_ty(&qself.ty);
783 this.visit_path(path, ty.id);
786 self.diagnostic_metadata.currently_processing_generics = prev;
794 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
795 GenericArg::Const(ct) => self.visit_anon_const(ct),
797 self.diagnostic_metadata.currently_processing_generics = prev;
800 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
801 if let Some(ref args) = path_segment.args {
803 GenericArgs::AngleBracketed(..) => visit::walk_generic_args(self, path_span, args),
804 GenericArgs::Parenthesized(..) => self
805 .with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough, |this| {
806 visit::walk_generic_args(this, path_span, args)
812 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
813 debug!("visit_where_predicate {:?}", p);
815 replace(&mut self.diagnostic_metadata.current_where_predicate, Some(p));
816 self.with_lifetime_rib(LifetimeRibKind::AnonymousReportError, |this| {
817 if let WherePredicate::BoundPredicate(WhereBoundPredicate {
820 ref bound_generic_params,
821 span: predicate_span,
825 let span = if bound_generic_params.is_empty() {
826 predicate_span.shrink_to_lo()
830 this.with_generic_param_rib(
831 &bound_generic_params,
833 LifetimeRibKind::Generics { kind: LifetimeBinderKind::WhereBound, span },
835 this.visit_generic_param_vec(&bound_generic_params, false);
836 this.visit_ty(bounded_ty);
837 for bound in bounds {
838 this.visit_param_bound(bound)
843 visit::walk_where_predicate(this, p);
846 self.diagnostic_metadata.current_where_predicate = previous_value;
849 fn visit_inline_asm_sym(&mut self, sym: &'ast InlineAsmSym) {
850 // This is similar to the code for AnonConst.
851 self.with_rib(ValueNS, InlineAsmSymRibKind, |this| {
852 this.with_rib(TypeNS, InlineAsmSymRibKind, |this| {
853 this.with_label_rib(InlineAsmSymRibKind, |this| {
854 this.smart_resolve_path(
858 PathSource::Expr(None),
860 visit::walk_inline_asm_sym(this, sym);
867 impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
868 fn new(resolver: &'b mut Resolver<'a>) -> LateResolutionVisitor<'a, 'b, 'ast> {
869 // During late resolution we only track the module component of the parent scope,
870 // although it may be useful to track other components as well for diagnostics.
871 let graph_root = resolver.graph_root;
872 let parent_scope = ParentScope::module(graph_root, resolver);
873 let start_rib_kind = ModuleRibKind(graph_root);
874 LateResolutionVisitor {
878 value_ns: vec![Rib::new(start_rib_kind)],
879 type_ns: vec![Rib::new(start_rib_kind)],
880 macro_ns: vec![Rib::new(start_rib_kind)],
882 label_ribs: Vec::new(),
883 lifetime_ribs: Vec::new(),
884 current_trait_ref: None,
885 diagnostic_metadata: DiagnosticMetadata::default(),
886 // errors at module scope should always be reported
891 fn maybe_resolve_ident_in_lexical_scope(
895 ) -> Option<LexicalScopeBinding<'a>> {
896 self.r.resolve_ident_in_lexical_scope(
906 fn resolve_ident_in_lexical_scope(
911 unusable_binding: Option<&'a NameBinding<'a>>,
912 ) -> Option<LexicalScopeBinding<'a>> {
913 self.r.resolve_ident_in_lexical_scope(
926 opt_ns: Option<Namespace>, // `None` indicates a module path in import
928 ) -> PathResult<'a> {
929 self.r.resolve_path_with_ribs(
941 // We maintain a list of value ribs and type ribs.
943 // Simultaneously, we keep track of the current position in the module
944 // graph in the `parent_scope.module` pointer. When we go to resolve a name in
945 // the value or type namespaces, we first look through all the ribs and
946 // then query the module graph. When we resolve a name in the module
947 // namespace, we can skip all the ribs (since nested modules are not
948 // allowed within blocks in Rust) and jump straight to the current module
951 // Named implementations are handled separately. When we find a method
952 // call, we consult the module node to find all of the implementations in
953 // scope. This information is lazily cached in the module node. We then
954 // generate a fake "implementation scope" containing all the
955 // implementations thus found, for compatibility with old resolve pass.
957 /// Do some `work` within a new innermost rib of the given `kind` in the given namespace (`ns`).
962 work: impl FnOnce(&mut Self) -> T,
964 self.ribs[ns].push(Rib::new(kind));
965 let ret = work(self);
970 fn with_scope<T>(&mut self, id: NodeId, f: impl FnOnce(&mut Self) -> T) -> T {
971 if let Some(module) = self.r.get_module(self.r.local_def_id(id).to_def_id()) {
972 // Move down in the graph.
973 let orig_module = replace(&mut self.parent_scope.module, module);
974 self.with_rib(ValueNS, ModuleRibKind(module), |this| {
975 this.with_rib(TypeNS, ModuleRibKind(module), |this| {
977 this.parent_scope.module = orig_module;
986 fn visit_generic_param_vec(&mut self, params: &'ast Vec<GenericParam>, add_self_upper: bool) {
987 // For type parameter defaults, we have to ban access
988 // to following type parameters, as the InternalSubsts can only
989 // provide previous type parameters as they're built. We
990 // put all the parameters on the ban list and then remove
991 // them one by one as they are processed and become available.
992 let mut forward_ty_ban_rib = Rib::new(ForwardGenericParamBanRibKind);
993 let mut forward_const_ban_rib = Rib::new(ForwardGenericParamBanRibKind);
994 for param in params.iter() {
996 GenericParamKind::Type { .. } => {
999 .insert(Ident::with_dummy_span(param.ident.name), Res::Err);
1001 GenericParamKind::Const { .. } => {
1002 forward_const_ban_rib
1004 .insert(Ident::with_dummy_span(param.ident.name), Res::Err);
1006 GenericParamKind::Lifetime => {}
1010 // rust-lang/rust#61631: The type `Self` is essentially
1011 // another type parameter. For ADTs, we consider it
1012 // well-defined only after all of the ADT type parameters have
1013 // been provided. Therefore, we do not allow use of `Self`
1014 // anywhere in ADT type parameter defaults.
1016 // (We however cannot ban `Self` for defaults on *all* generic
1017 // lists; e.g. trait generics can usefully refer to `Self`,
1018 // such as in the case of `trait Add<Rhs = Self>`.)
1020 // (`Some` if + only if we are in ADT's generics.)
1021 forward_ty_ban_rib.bindings.insert(Ident::with_dummy_span(kw::SelfUpper), Res::Err);
1024 self.with_lifetime_rib(LifetimeRibKind::AnonymousReportError, |this| {
1025 for param in params {
1027 GenericParamKind::Lifetime => {
1028 for bound in ¶m.bounds {
1029 this.visit_param_bound(bound);
1032 GenericParamKind::Type { ref default } => {
1033 for bound in ¶m.bounds {
1034 this.visit_param_bound(bound);
1037 if let Some(ref ty) = default {
1038 this.ribs[TypeNS].push(forward_ty_ban_rib);
1039 this.ribs[ValueNS].push(forward_const_ban_rib);
1041 forward_const_ban_rib = this.ribs[ValueNS].pop().unwrap();
1042 forward_ty_ban_rib = this.ribs[TypeNS].pop().unwrap();
1045 // Allow all following defaults to refer to this type parameter.
1048 .remove(&Ident::with_dummy_span(param.ident.name));
1050 GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
1051 // Const parameters can't have param bounds.
1052 assert!(param.bounds.is_empty());
1054 this.ribs[TypeNS].push(Rib::new(ConstParamTyRibKind));
1055 this.ribs[ValueNS].push(Rib::new(ConstParamTyRibKind));
1057 this.ribs[TypeNS].pop().unwrap();
1058 this.ribs[ValueNS].pop().unwrap();
1060 if let Some(ref expr) = default {
1061 this.ribs[TypeNS].push(forward_ty_ban_rib);
1062 this.ribs[ValueNS].push(forward_const_ban_rib);
1063 this.visit_anon_const(expr);
1064 forward_const_ban_rib = this.ribs[ValueNS].pop().unwrap();
1065 forward_ty_ban_rib = this.ribs[TypeNS].pop().unwrap();
1068 // Allow all following defaults to refer to this const parameter.
1069 forward_const_ban_rib
1071 .remove(&Ident::with_dummy_span(param.ident.name));
1078 #[tracing::instrument(level = "debug", skip(self, work))]
1079 fn with_lifetime_rib<T>(
1081 kind: LifetimeRibKind,
1082 work: impl FnOnce(&mut Self) -> T,
1084 self.lifetime_ribs.push(LifetimeRib::new(kind));
1085 let ret = work(self);
1086 self.lifetime_ribs.pop();
1090 #[tracing::instrument(level = "debug", skip(self))]
1091 fn resolve_lifetime(&mut self, lifetime: &'ast Lifetime) {
1092 let ident = lifetime.ident;
1094 if ident.name == kw::StaticLifetime {
1098 if ident.name == kw::UnderscoreLifetime {
1099 return self.resolve_anonymous_lifetime(lifetime, false);
1102 let mut indices = (0..self.lifetime_ribs.len()).rev();
1103 for i in &mut indices {
1104 let rib = &self.lifetime_ribs[i];
1105 let normalized_ident = ident.normalize_to_macros_2_0();
1106 if let Some(_) = rib.bindings.get_key_value(&normalized_ident) {
1110 if let LifetimeRibKind::Item = rib.kind {
1115 let mut outer_res = None;
1117 let rib = &self.lifetime_ribs[i];
1118 let normalized_ident = ident.normalize_to_macros_2_0();
1119 if let Some((&outer, _)) = rib.bindings.get_key_value(&normalized_ident) {
1120 outer_res = Some(outer);
1125 self.emit_undeclared_lifetime_error(lifetime, outer_res);
1128 #[tracing::instrument(level = "debug", skip(self))]
1129 fn resolve_anonymous_lifetime(&mut self, lifetime: &Lifetime, elided: bool) {
1130 debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
1132 for i in (0..self.lifetime_ribs.len()).rev() {
1133 let rib = &mut self.lifetime_ribs[i];
1135 LifetimeRibKind::AnonymousReportError => {
1136 let (msg, note) = if elided {
1138 "`&` without an explicit lifetime name cannot be used here",
1139 "explicit lifetime name needed here",
1142 ("`'_` cannot be used here", "`'_` is a reserved lifetime name")
1144 rustc_errors::struct_span_err!(
1146 lifetime.ident.span,
1151 .span_label(lifetime.ident.span, note)
1156 LifetimeRibKind::AnonymousCreateParameter
1157 | LifetimeRibKind::AnonymousPassThrough
1158 | LifetimeRibKind::Item => return,
1164 #[tracing::instrument(level = "debug", skip(self))]
1165 fn resolve_elided_lifetime(&mut self, anchor_id: NodeId, span: Span) {
1166 let id = self.r.next_node_id();
1167 let lt = Lifetime { id, ident: Ident::new(kw::UnderscoreLifetime, span) };
1168 self.resolve_anonymous_lifetime(<, true);
1171 #[tracing::instrument(level = "debug", skip(self))]
1172 fn resolve_elided_lifetimes_in_path(
1175 partial_res: PartialRes,
1177 source: PathSource<'_>,
1180 let Some(path_span) = finalize.path_span() else {
1183 let proj_start = path.len() - partial_res.unresolved_segments();
1184 for (i, segment) in path.iter().enumerate() {
1185 if segment.has_lifetime_args {
1188 let Some(segment_id) = segment.id else {
1192 // Figure out if this is a type/trait segment,
1193 // which may need lifetime elision performed.
1194 let type_def_id = match partial_res.base_res() {
1195 Res::Def(DefKind::AssocTy, def_id) if i + 2 == proj_start => {
1196 self.r.parent(def_id).unwrap()
1198 Res::Def(DefKind::Variant, def_id) if i + 1 == proj_start => {
1199 self.r.parent(def_id).unwrap()
1201 Res::Def(DefKind::Struct, def_id)
1202 | Res::Def(DefKind::Union, def_id)
1203 | Res::Def(DefKind::Enum, def_id)
1204 | Res::Def(DefKind::TyAlias, def_id)
1205 | Res::Def(DefKind::Trait, def_id)
1206 if i + 1 == proj_start =>
1213 let expected_lifetimes = self.r.item_generics_num_lifetimes(type_def_id);
1214 if expected_lifetimes == 0 {
1218 let missing = match source {
1219 PathSource::Trait(..) | PathSource::TraitItem(..) | PathSource::Type => true,
1220 PathSource::Expr(..)
1222 | PathSource::Struct
1223 | PathSource::TupleStruct(..) => false,
1225 let mut error = false;
1226 for rib in self.lifetime_ribs.iter().rev() {
1228 // In create-parameter mode we error here because we don't want to support
1229 // deprecated impl elision in new features like impl elision and `async fn`,
1230 // both of which work using the `CreateParameter` mode:
1232 // impl Foo for std::cell::Ref<u32> // note lack of '_
1233 // async fn foo(_: std::cell::Ref<u32>) { ... }
1234 LifetimeRibKind::AnonymousCreateParameter => {
1238 // `PassThrough` is the normal case.
1239 // `new_error_lifetime`, which would usually be used in the case of `ReportError`,
1240 // is unsuitable here, as these can occur from missing lifetime parameters in a
1241 // `PathSegment`, for which there is no associated `'_` or `&T` with no explicit
1242 // lifetime. Instead, we simply create an implicit lifetime, which will be checked
1243 // later, at which point a suitable error will be emitted.
1244 LifetimeRibKind::AnonymousPassThrough
1245 | LifetimeRibKind::AnonymousReportError
1246 | LifetimeRibKind::Item => break,
1255 let elided_lifetime_span = if segment.has_generic_args {
1256 // If there are brackets, but not generic arguments, then use the opening bracket
1257 segment.args_span.with_hi(segment.args_span.lo() + BytePos(1))
1259 // If there are no brackets, use the identifier span.
1260 // HACK: we use find_ancestor_inside to properly suggest elided spans in paths
1261 // originating from macros, since the segment's span might be from a macro arg.
1262 segment.ident.span.find_ancestor_inside(path_span).unwrap_or(path_span)
1265 let sess = self.r.session;
1266 let mut err = rustc_errors::struct_span_err!(
1270 "implicit elided lifetime not allowed here"
1272 rustc_errors::add_elided_lifetime_in_path_suggestion(
1277 !segment.has_generic_args,
1278 elided_lifetime_span,
1280 err.note("assuming a `'static` lifetime...");
1283 self.r.lint_buffer.buffer_lint_with_diagnostic(
1284 lint::builtin::ELIDED_LIFETIMES_IN_PATHS,
1286 elided_lifetime_span,
1287 "hidden lifetime parameters in types are deprecated",
1288 lint::BuiltinLintDiagnostics::ElidedLifetimesInPaths(
1291 !segment.has_generic_args,
1292 elided_lifetime_span,
1299 /// Searches the current set of local scopes for labels. Returns the `NodeId` of the resolved
1300 /// label and reports an error if the label is not found or is unreachable.
1301 fn resolve_label(&self, mut label: Ident) -> Option<NodeId> {
1302 let mut suggestion = None;
1304 // Preserve the original span so that errors contain "in this macro invocation"
1306 let original_span = label.span;
1308 for i in (0..self.label_ribs.len()).rev() {
1309 let rib = &self.label_ribs[i];
1311 if let MacroDefinition(def) = rib.kind {
1312 // If an invocation of this macro created `ident`, give up on `ident`
1313 // and switch to `ident`'s source from the macro definition.
1314 if def == self.r.macro_def(label.span.ctxt()) {
1315 label.span.remove_mark();
1319 let ident = label.normalize_to_macro_rules();
1320 if let Some((ident, id)) = rib.bindings.get_key_value(&ident) {
1321 return if self.is_label_valid_from_rib(i) {
1326 ResolutionError::UnreachableLabel {
1328 definition_span: ident.span,
1337 // Diagnostics: Check if this rib contains a label with a similar name, keep track of
1338 // the first such label that is encountered.
1339 suggestion = suggestion.or_else(|| self.suggestion_for_label_in_rib(i, label));
1344 ResolutionError::UndeclaredLabel { name: label.name, suggestion },
1349 /// Determine whether or not a label from the `rib_index`th label rib is reachable.
1350 fn is_label_valid_from_rib(&self, rib_index: usize) -> bool {
1351 let ribs = &self.label_ribs[rib_index + 1..];
1355 NormalRibKind | MacroDefinition(..) => {
1356 // Nothing to do. Continue.
1360 | ClosureOrAsyncRibKind
1363 | ConstantItemRibKind(..)
1365 | ForwardGenericParamBanRibKind
1366 | ConstParamTyRibKind
1367 | InlineAsmSymRibKind => {
1376 fn resolve_adt(&mut self, item: &'ast Item, generics: &'ast Generics) {
1377 debug!("resolve_adt");
1378 self.with_current_self_item(item, |this| {
1379 this.with_generic_param_rib(
1381 ItemRibKind(HasGenericParams::Yes),
1382 LifetimeRibKind::Generics { kind: LifetimeBinderKind::Item, span: generics.span },
1384 let item_def_id = this.r.local_def_id(item.id).to_def_id();
1386 Res::SelfTy { trait_: None, alias_to: Some((item_def_id, false)) },
1388 visit::walk_item(this, item);
1396 fn future_proof_import(&mut self, use_tree: &UseTree) {
1397 let segments = &use_tree.prefix.segments;
1398 if !segments.is_empty() {
1399 let ident = segments[0].ident;
1400 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
1404 let nss = match use_tree.kind {
1405 UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
1408 let report_error = |this: &Self, ns| {
1409 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
1410 if this.should_report_errs() {
1413 .span_err(ident.span, &format!("imports cannot refer to {}", what));
1418 match self.maybe_resolve_ident_in_lexical_scope(ident, ns) {
1419 Some(LexicalScopeBinding::Res(..)) => {
1420 report_error(self, ns);
1422 Some(LexicalScopeBinding::Item(binding)) => {
1423 if let Some(LexicalScopeBinding::Res(..)) = self
1424 .resolve_ident_in_lexical_scope(ident, ns, Finalize::No, Some(binding))
1426 report_error(self, ns);
1432 } else if let UseTreeKind::Nested(use_trees) = &use_tree.kind {
1433 for (use_tree, _) in use_trees {
1434 self.future_proof_import(use_tree);
1439 fn resolve_item(&mut self, item: &'ast Item) {
1440 let name = item.ident.name;
1441 debug!("(resolving item) resolving {} ({:?})", name, item.kind);
1444 ItemKind::TyAlias(box TyAlias { ref generics, .. }) => {
1445 self.with_generic_param_rib(
1447 ItemRibKind(HasGenericParams::Yes),
1448 LifetimeRibKind::Generics {
1449 kind: LifetimeBinderKind::Item,
1450 span: generics.span,
1452 |this| visit::walk_item(this, item),
1456 ItemKind::Fn(box Fn { ref generics, .. }) => {
1457 self.with_generic_param_rib(
1459 ItemRibKind(HasGenericParams::Yes),
1460 LifetimeRibKind::Generics {
1461 kind: LifetimeBinderKind::Function,
1462 span: generics.span,
1464 |this| visit::walk_item(this, item),
1468 ItemKind::Enum(_, ref generics)
1469 | ItemKind::Struct(_, ref generics)
1470 | ItemKind::Union(_, ref generics) => {
1471 self.resolve_adt(item, generics);
1474 ItemKind::Impl(box Impl {
1478 items: ref impl_items,
1481 self.resolve_implementation(generics, of_trait, &self_ty, item.id, impl_items);
1484 ItemKind::Trait(box Trait { ref generics, ref bounds, ref items, .. }) => {
1485 // Create a new rib for the trait-wide type parameters.
1486 self.with_generic_param_rib(
1488 ItemRibKind(HasGenericParams::Yes),
1489 LifetimeRibKind::Generics {
1490 kind: LifetimeBinderKind::Item,
1491 span: generics.span,
1494 let local_def_id = this.r.local_def_id(item.id).to_def_id();
1496 Res::SelfTy { trait_: Some(local_def_id), alias_to: None },
1498 this.visit_generics(generics);
1499 walk_list!(this, visit_param_bound, bounds);
1501 let walk_assoc_item =
1503 generics: &Generics,
1505 item: &'ast AssocItem| {
1506 this.with_generic_param_rib(
1509 LifetimeRibKind::Generics { span: generics.span, kind },
1511 visit::walk_assoc_item(this, item, AssocCtxt::Trait)
1516 this.with_trait_items(items, |this| {
1519 AssocItemKind::Const(_, ty, default) => {
1521 // Only impose the restrictions of `ConstRibKind` for an
1522 // actual constant expression in a provided default.
1523 if let Some(expr) = default {
1524 // We allow arbitrary const expressions inside of associated consts,
1525 // even if they are potentially not const evaluatable.
1527 // Type parameters can already be used and as associated consts are
1528 // not used as part of the type system, this is far less surprising.
1529 this.with_constant_rib(
1533 |this| this.visit_expr(expr),
1537 AssocItemKind::Fn(box Fn { generics, .. }) => {
1541 LifetimeBinderKind::Function,
1545 AssocItemKind::TyAlias(box TyAlias {
1552 LifetimeBinderKind::Item,
1556 AssocItemKind::MacCall(_) => {
1557 panic!("unexpanded macro in resolve!")
1568 ItemKind::TraitAlias(ref generics, ref bounds) => {
1569 // Create a new rib for the trait-wide type parameters.
1570 self.with_generic_param_rib(
1572 ItemRibKind(HasGenericParams::Yes),
1573 LifetimeRibKind::Generics {
1574 kind: LifetimeBinderKind::Item,
1575 span: generics.span,
1578 let local_def_id = this.r.local_def_id(item.id).to_def_id();
1580 Res::SelfTy { trait_: Some(local_def_id), alias_to: None },
1582 this.visit_generics(generics);
1583 walk_list!(this, visit_param_bound, bounds);
1590 ItemKind::Mod(..) | ItemKind::ForeignMod(_) => {
1591 self.with_scope(item.id, |this| {
1592 visit::walk_item(this, item);
1596 ItemKind::Static(ref ty, _, ref expr) | ItemKind::Const(_, ref ty, ref expr) => {
1597 self.with_item_rib(|this| {
1599 if let Some(expr) = expr {
1600 let constant_item_kind = match item.kind {
1601 ItemKind::Const(..) => ConstantItemKind::Const,
1602 ItemKind::Static(..) => ConstantItemKind::Static,
1603 _ => unreachable!(),
1605 // We already forbid generic params because of the above item rib,
1606 // so it doesn't matter whether this is a trivial constant.
1607 this.with_constant_rib(
1610 Some((item.ident, constant_item_kind)),
1611 |this| this.visit_expr(expr),
1617 ItemKind::Use(ref use_tree) => {
1618 self.future_proof_import(use_tree);
1621 ItemKind::ExternCrate(..) | ItemKind::MacroDef(..) => {
1622 // do nothing, these are just around to be encoded
1625 ItemKind::GlobalAsm(_) => {
1626 visit::walk_item(self, item);
1629 ItemKind::MacCall(_) => panic!("unexpanded macro in resolve!"),
1633 fn with_generic_param_rib<'c, F>(
1635 params: &'c Vec<GenericParam>,
1637 lifetime_kind: LifetimeRibKind,
1640 F: FnOnce(&mut Self),
1642 debug!("with_generic_param_rib");
1643 let mut function_type_rib = Rib::new(kind);
1644 let mut function_value_rib = Rib::new(kind);
1645 let mut function_lifetime_rib = LifetimeRib::new(lifetime_kind);
1646 let mut seen_bindings = FxHashMap::default();
1648 // We also can't shadow bindings from the parent item
1649 if let AssocItemRibKind = kind {
1650 let mut add_bindings_for_ns = |ns| {
1651 let parent_rib = self.ribs[ns]
1653 .rfind(|r| matches!(r.kind, ItemRibKind(_)))
1654 .expect("associated item outside of an item");
1656 .extend(parent_rib.bindings.iter().map(|(ident, _)| (*ident, ident.span)));
1658 add_bindings_for_ns(ValueNS);
1659 add_bindings_for_ns(TypeNS);
1662 for param in params {
1663 let ident = param.ident.normalize_to_macros_2_0();
1664 debug!("with_generic_param_rib: {}", param.id);
1666 match seen_bindings.entry(ident) {
1667 Entry::Occupied(entry) => {
1668 let span = *entry.get();
1669 let err = ResolutionError::NameAlreadyUsedInParameterList(ident.name, span);
1670 if !matches!(param.kind, GenericParamKind::Lifetime) {
1671 self.report_error(param.ident.span, err);
1674 Entry::Vacant(entry) => {
1675 entry.insert(param.ident.span);
1679 if param.ident.name == kw::UnderscoreLifetime {
1680 rustc_errors::struct_span_err!(
1684 "`'_` cannot be used here"
1686 .span_label(param.ident.span, "`'_` is a reserved lifetime name")
1691 if param.ident.name == kw::StaticLifetime {
1692 rustc_errors::struct_span_err!(
1696 "invalid lifetime parameter name: `{}`",
1699 .span_label(param.ident.span, format!("'static is a reserved lifetime name"))
1704 let def_id = self.r.local_def_id(param.id);
1706 // Plain insert (no renaming).
1707 let (rib, def_kind) = match param.kind {
1708 GenericParamKind::Type { .. } => (&mut function_type_rib, DefKind::TyParam),
1709 GenericParamKind::Const { .. } => (&mut function_value_rib, DefKind::ConstParam),
1710 GenericParamKind::Lifetime => {
1711 function_lifetime_rib.bindings.insert(ident, ());
1715 let res = Res::Def(def_kind, def_id.to_def_id());
1716 self.r.record_partial_res(param.id, PartialRes::new(res));
1717 rib.bindings.insert(ident, res);
1720 self.lifetime_ribs.push(function_lifetime_rib);
1721 self.ribs[ValueNS].push(function_value_rib);
1722 self.ribs[TypeNS].push(function_type_rib);
1726 self.ribs[TypeNS].pop();
1727 self.ribs[ValueNS].pop();
1728 self.lifetime_ribs.pop();
1731 fn with_label_rib(&mut self, kind: RibKind<'a>, f: impl FnOnce(&mut Self)) {
1732 self.label_ribs.push(Rib::new(kind));
1734 self.label_ribs.pop();
1737 fn with_item_rib(&mut self, f: impl FnOnce(&mut Self)) {
1738 let kind = ItemRibKind(HasGenericParams::No);
1739 self.with_lifetime_rib(LifetimeRibKind::Item, |this| {
1740 this.with_rib(ValueNS, kind, |this| this.with_rib(TypeNS, kind, f))
1744 // HACK(min_const_generics,const_evaluatable_unchecked): We
1745 // want to keep allowing `[0; std::mem::size_of::<*mut T>()]`
1746 // with a future compat lint for now. We do this by adding an
1747 // additional special case for repeat expressions.
1749 // Note that we intentionally still forbid `[0; N + 1]` during
1750 // name resolution so that we don't extend the future
1751 // compat lint to new cases.
1752 fn with_constant_rib(
1754 is_repeat: IsRepeatExpr,
1756 item: Option<(Ident, ConstantItemKind)>,
1757 f: impl FnOnce(&mut Self),
1759 debug!("with_constant_rib: is_repeat={:?} is_trivial={}", is_repeat, is_trivial);
1760 self.with_rib(ValueNS, ConstantItemRibKind(is_trivial, item), |this| {
1763 ConstantItemRibKind(is_repeat == IsRepeatExpr::Yes || is_trivial, item),
1765 this.with_label_rib(ConstantItemRibKind(is_trivial, item), f);
1771 fn with_current_self_type<T>(&mut self, self_type: &Ty, f: impl FnOnce(&mut Self) -> T) -> T {
1772 // Handle nested impls (inside fn bodies)
1773 let previous_value =
1774 replace(&mut self.diagnostic_metadata.current_self_type, Some(self_type.clone()));
1775 let result = f(self);
1776 self.diagnostic_metadata.current_self_type = previous_value;
1780 fn with_current_self_item<T>(&mut self, self_item: &Item, f: impl FnOnce(&mut Self) -> T) -> T {
1781 let previous_value =
1782 replace(&mut self.diagnostic_metadata.current_self_item, Some(self_item.id));
1783 let result = f(self);
1784 self.diagnostic_metadata.current_self_item = previous_value;
1788 /// When evaluating a `trait` use its associated types' idents for suggestions in E0412.
1789 fn with_trait_items<T>(
1791 trait_items: &'ast [P<AssocItem>],
1792 f: impl FnOnce(&mut Self) -> T,
1794 let trait_assoc_items =
1795 replace(&mut self.diagnostic_metadata.current_trait_assoc_items, Some(&trait_items));
1796 let result = f(self);
1797 self.diagnostic_metadata.current_trait_assoc_items = trait_assoc_items;
1801 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
1802 fn with_optional_trait_ref<T>(
1804 opt_trait_ref: Option<&TraitRef>,
1805 f: impl FnOnce(&mut Self, Option<DefId>) -> T,
1807 let mut new_val = None;
1808 let mut new_id = None;
1809 if let Some(trait_ref) = opt_trait_ref {
1810 let path: Vec<_> = Segment::from_path(&trait_ref.path);
1811 let res = self.smart_resolve_path_fragment(
1814 PathSource::Trait(AliasPossibility::No),
1815 Finalize::SimplePath(trait_ref.ref_id, trait_ref.path.span),
1817 if let Some(def_id) = res.base_res().opt_def_id() {
1818 new_id = Some(def_id);
1819 new_val = Some((self.r.expect_module(def_id), trait_ref.clone()));
1822 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1823 let result = f(self, new_id);
1824 self.current_trait_ref = original_trait_ref;
1828 fn with_self_rib_ns(&mut self, ns: Namespace, self_res: Res, f: impl FnOnce(&mut Self)) {
1829 let mut self_type_rib = Rib::new(NormalRibKind);
1831 // Plain insert (no renaming, since types are not currently hygienic)
1832 self_type_rib.bindings.insert(Ident::with_dummy_span(kw::SelfUpper), self_res);
1833 self.ribs[ns].push(self_type_rib);
1835 self.ribs[ns].pop();
1838 fn with_self_rib(&mut self, self_res: Res, f: impl FnOnce(&mut Self)) {
1839 self.with_self_rib_ns(TypeNS, self_res, f)
1842 fn resolve_implementation(
1844 generics: &'ast Generics,
1845 opt_trait_reference: &'ast Option<TraitRef>,
1846 self_type: &'ast Ty,
1848 impl_items: &'ast [P<AssocItem>],
1850 debug!("resolve_implementation");
1851 // If applicable, create a rib for the type parameters.
1852 self.with_generic_param_rib(&generics.params, ItemRibKind(HasGenericParams::Yes), LifetimeRibKind::Generics { span: generics.span, kind: LifetimeBinderKind::ImplBlock }, |this| {
1853 // Dummy self type for better errors if `Self` is used in the trait path.
1854 this.with_self_rib(Res::SelfTy { trait_: None, alias_to: None }, |this| {
1855 this.with_lifetime_rib(LifetimeRibKind::AnonymousCreateParameter, |this| {
1856 // Resolve the trait reference, if necessary.
1857 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1858 let item_def_id = this.r.local_def_id(item_id);
1860 // Register the trait definitions from here.
1861 if let Some(trait_id) = trait_id {
1862 this.r.trait_impls.entry(trait_id).or_default().push(item_def_id);
1865 let item_def_id = item_def_id.to_def_id();
1867 Res::SelfTy { trait_: trait_id, alias_to: Some((item_def_id, false)) };
1868 this.with_self_rib(res, |this| {
1869 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1870 // Resolve type arguments in the trait path.
1871 visit::walk_trait_ref(this, trait_ref);
1873 // Resolve the self type.
1874 this.visit_ty(self_type);
1875 // Resolve the generic parameters.
1876 this.visit_generics(generics);
1878 // Resolve the items within the impl.
1879 this.with_lifetime_rib(LifetimeRibKind::AnonymousPassThrough,
1881 this.with_current_self_type(self_type, |this| {
1882 this.with_self_rib_ns(ValueNS, Res::SelfCtor(item_def_id), |this| {
1883 debug!("resolve_implementation with_self_rib_ns(ValueNS, ...)");
1884 for item in impl_items {
1885 use crate::ResolutionError::*;
1887 AssocItemKind::Const(_default, _ty, _expr) => {
1888 debug!("resolve_implementation AssocItemKind::Const");
1889 // If this is a trait impl, ensure the const
1891 this.check_trait_item(
1897 |i, s, c| ConstNotMemberOfTrait(i, s, c),
1900 // We allow arbitrary const expressions inside of associated consts,
1901 // even if they are potentially not const evaluatable.
1903 // Type parameters can already be used and as associated consts are
1904 // not used as part of the type system, this is far less surprising.
1905 this.with_constant_rib(
1910 visit::walk_assoc_item(
1918 AssocItemKind::Fn(box Fn { generics, .. }) => {
1919 debug!("resolve_implementation AssocItemKind::Fn");
1920 // We also need a new scope for the impl item type parameters.
1921 this.with_generic_param_rib(
1924 LifetimeRibKind::Generics { span: generics.span, kind: LifetimeBinderKind::Function },
1926 // If this is a trait impl, ensure the method
1928 this.check_trait_item(
1934 |i, s, c| MethodNotMemberOfTrait(i, s, c),
1937 visit::walk_assoc_item(
1945 AssocItemKind::TyAlias(box TyAlias {
1948 debug!("resolve_implementation AssocItemKind::TyAlias");
1949 // We also need a new scope for the impl item type parameters.
1950 this.with_generic_param_rib(
1953 LifetimeRibKind::Generics { span: generics.span, kind: LifetimeBinderKind::Item },
1955 // If this is a trait impl, ensure the type
1957 this.check_trait_item(
1963 |i, s, c| TypeNotMemberOfTrait(i, s, c),
1966 visit::walk_assoc_item(
1974 AssocItemKind::MacCall(_) => {
1975 panic!("unexpanded macro in resolve!")
1990 fn check_trait_item<F>(
1994 kind: &AssocItemKind,
1999 F: FnOnce(Ident, &str, Option<Symbol>) -> ResolutionError<'_>,
2001 // If there is a TraitRef in scope for an impl, then the method must be in the trait.
2002 let Some((module, _)) = &self.current_trait_ref else { return; };
2003 ident.span.normalize_to_macros_2_0_and_adjust(module.expansion);
2004 let key = self.r.new_key(ident, ns);
2005 let mut binding = self.r.resolution(module, key).try_borrow().ok().and_then(|r| r.binding);
2007 if binding.is_none() {
2008 // We could not find the trait item in the correct namespace.
2009 // Check the other namespace to report an error.
2015 let key = self.r.new_key(ident, ns);
2016 binding = self.r.resolution(module, key).try_borrow().ok().and_then(|r| r.binding);
2019 let Some(binding) = binding else {
2020 // We could not find the method: report an error.
2021 let candidate = self.find_similarly_named_assoc_item(ident.name, kind);
2022 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2023 self.report_error(span, err(ident, &path_names_to_string(path), candidate));
2027 let res = binding.res();
2028 let Res::Def(def_kind, _) = res else { bug!() };
2029 match (def_kind, kind) {
2030 (DefKind::AssocTy, AssocItemKind::TyAlias(..))
2031 | (DefKind::AssocFn, AssocItemKind::Fn(..))
2032 | (DefKind::AssocConst, AssocItemKind::Const(..)) => {
2033 self.r.record_partial_res(id, PartialRes::new(res));
2039 // The method kind does not correspond to what appeared in the trait, report.
2040 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2041 let (code, kind) = match kind {
2042 AssocItemKind::Const(..) => (rustc_errors::error_code!(E0323), "const"),
2043 AssocItemKind::Fn(..) => (rustc_errors::error_code!(E0324), "method"),
2044 AssocItemKind::TyAlias(..) => (rustc_errors::error_code!(E0325), "type"),
2045 AssocItemKind::MacCall(..) => span_bug!(span, "unexpanded macro"),
2049 ResolutionError::TraitImplMismatch {
2053 trait_path: path_names_to_string(path),
2054 trait_item_span: binding.span,
2059 fn resolve_params(&mut self, params: &'ast [Param]) {
2060 let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
2061 for Param { pat, ty, .. } in params {
2062 self.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
2064 debug!("(resolving function / closure) recorded parameter");
2068 fn resolve_local(&mut self, local: &'ast Local) {
2069 debug!("resolving local ({:?})", local);
2070 // Resolve the type.
2071 walk_list!(self, visit_ty, &local.ty);
2073 // Resolve the initializer.
2074 if let Some((init, els)) = local.kind.init_else_opt() {
2075 self.visit_expr(init);
2077 // Resolve the `else` block
2078 if let Some(els) = els {
2079 self.visit_block(els);
2083 // Resolve the pattern.
2084 self.resolve_pattern_top(&local.pat, PatternSource::Let);
2087 /// build a map from pattern identifiers to binding-info's.
2088 /// this is done hygienically. This could arise for a macro
2089 /// that expands into an or-pattern where one 'x' was from the
2090 /// user and one 'x' came from the macro.
2091 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2092 let mut binding_map = FxHashMap::default();
2094 pat.walk(&mut |pat| {
2096 PatKind::Ident(binding_mode, ident, ref sub_pat)
2097 if sub_pat.is_some() || self.is_base_res_local(pat.id) =>
2099 binding_map.insert(ident, BindingInfo { span: ident.span, binding_mode });
2101 PatKind::Or(ref ps) => {
2102 // Check the consistency of this or-pattern and
2103 // then add all bindings to the larger map.
2104 for bm in self.check_consistent_bindings(ps) {
2105 binding_map.extend(bm);
2118 fn is_base_res_local(&self, nid: NodeId) -> bool {
2119 matches!(self.r.partial_res_map.get(&nid).map(|res| res.base_res()), Some(Res::Local(..)))
2122 /// Checks that all of the arms in an or-pattern have exactly the
2123 /// same set of bindings, with the same binding modes for each.
2124 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) -> Vec<BindingMap> {
2125 let mut missing_vars = FxHashMap::default();
2126 let mut inconsistent_vars = FxHashMap::default();
2128 // 1) Compute the binding maps of all arms.
2129 let maps = pats.iter().map(|pat| self.binding_mode_map(pat)).collect::<Vec<_>>();
2131 // 2) Record any missing bindings or binding mode inconsistencies.
2132 for (map_outer, pat_outer) in pats.iter().enumerate().map(|(idx, pat)| (&maps[idx], pat)) {
2133 // Check against all arms except for the same pattern which is always self-consistent.
2137 .filter(|(_, pat)| pat.id != pat_outer.id)
2138 .flat_map(|(idx, _)| maps[idx].iter())
2139 .map(|(key, binding)| (key.name, map_outer.get(&key), binding));
2141 for (name, info, &binding_inner) in inners {
2144 // The inner binding is missing in the outer.
2146 missing_vars.entry(name).or_insert_with(|| BindingError {
2148 origin: BTreeSet::new(),
2149 target: BTreeSet::new(),
2150 could_be_path: name.as_str().starts_with(char::is_uppercase),
2152 binding_error.origin.insert(binding_inner.span);
2153 binding_error.target.insert(pat_outer.span);
2155 Some(binding_outer) => {
2156 if binding_outer.binding_mode != binding_inner.binding_mode {
2157 // The binding modes in the outer and inner bindings differ.
2160 .or_insert((binding_inner.span, binding_outer.span));
2167 // 3) Report all missing variables we found.
2168 let mut missing_vars = missing_vars.iter_mut().collect::<Vec<_>>();
2169 missing_vars.sort_by_key(|(sym, _err)| sym.as_str());
2171 for (name, mut v) in missing_vars {
2172 if inconsistent_vars.contains_key(name) {
2173 v.could_be_path = false;
2176 *v.origin.iter().next().unwrap(),
2177 ResolutionError::VariableNotBoundInPattern(v),
2181 // 4) Report all inconsistencies in binding modes we found.
2182 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2183 inconsistent_vars.sort();
2184 for (name, v) in inconsistent_vars {
2185 self.report_error(v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2188 // 5) Finally bubble up all the binding maps.
2192 /// Check the consistency of the outermost or-patterns.
2193 fn check_consistent_bindings_top(&mut self, pat: &'ast Pat) {
2194 pat.walk(&mut |pat| match pat.kind {
2195 PatKind::Or(ref ps) => {
2196 self.check_consistent_bindings(ps);
2203 fn resolve_arm(&mut self, arm: &'ast Arm) {
2204 self.with_rib(ValueNS, NormalRibKind, |this| {
2205 this.resolve_pattern_top(&arm.pat, PatternSource::Match);
2206 walk_list!(this, visit_expr, &arm.guard);
2207 this.visit_expr(&arm.body);
2211 /// Arising from `source`, resolve a top level pattern.
2212 fn resolve_pattern_top(&mut self, pat: &'ast Pat, pat_src: PatternSource) {
2213 let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
2214 self.resolve_pattern(pat, pat_src, &mut bindings);
2220 pat_src: PatternSource,
2221 bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
2223 // We walk the pattern before declaring the pattern's inner bindings,
2224 // so that we avoid resolving a literal expression to a binding defined
2226 visit::walk_pat(self, pat);
2227 self.resolve_pattern_inner(pat, pat_src, bindings);
2228 // This has to happen *after* we determine which pat_idents are variants:
2229 self.check_consistent_bindings_top(pat);
2232 /// Resolve bindings in a pattern. This is a helper to `resolve_pattern`.
2236 /// A stack of sets of bindings accumulated.
2238 /// In each set, `PatBoundCtx::Product` denotes that a found binding in it should
2239 /// be interpreted as re-binding an already bound binding. This results in an error.
2240 /// Meanwhile, `PatBound::Or` denotes that a found binding in the set should result
2241 /// in reusing this binding rather than creating a fresh one.
2243 /// When called at the top level, the stack must have a single element
2244 /// with `PatBound::Product`. Otherwise, pushing to the stack happens as
2245 /// or-patterns (`p_0 | ... | p_n`) are encountered and the context needs
2246 /// to be switched to `PatBoundCtx::Or` and then `PatBoundCtx::Product` for each `p_i`.
2247 /// When each `p_i` has been dealt with, the top set is merged with its parent.
2248 /// When a whole or-pattern has been dealt with, the thing happens.
2250 /// See the implementation and `fresh_binding` for more details.
2251 fn resolve_pattern_inner(
2254 pat_src: PatternSource,
2255 bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
2257 // Visit all direct subpatterns of this pattern.
2258 pat.walk(&mut |pat| {
2259 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.kind);
2261 PatKind::Ident(bmode, ident, ref sub) => {
2262 // First try to resolve the identifier as some existing entity,
2263 // then fall back to a fresh binding.
2264 let has_sub = sub.is_some();
2266 .try_resolve_as_non_binding(pat_src, bmode, ident, has_sub)
2267 .unwrap_or_else(|| self.fresh_binding(ident, pat.id, pat_src, bindings));
2268 self.r.record_partial_res(pat.id, PartialRes::new(res));
2269 self.r.record_pat_span(pat.id, pat.span);
2271 PatKind::TupleStruct(ref qself, ref path, ref sub_patterns) => {
2272 self.smart_resolve_path(
2276 PathSource::TupleStruct(
2278 self.r.arenas.alloc_pattern_spans(sub_patterns.iter().map(|p| p.span)),
2282 PatKind::Path(ref qself, ref path) => {
2283 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2285 PatKind::Struct(ref qself, ref path, ..) => {
2286 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Struct);
2288 PatKind::Or(ref ps) => {
2289 // Add a new set of bindings to the stack. `Or` here records that when a
2290 // binding already exists in this set, it should not result in an error because
2291 // `V1(a) | V2(a)` must be allowed and are checked for consistency later.
2292 bindings.push((PatBoundCtx::Or, Default::default()));
2294 // Now we need to switch back to a product context so that each
2295 // part of the or-pattern internally rejects already bound names.
2296 // For example, `V1(a) | V2(a, a)` and `V1(a, a) | V2(a)` are bad.
2297 bindings.push((PatBoundCtx::Product, Default::default()));
2298 self.resolve_pattern_inner(p, pat_src, bindings);
2299 // Move up the non-overlapping bindings to the or-pattern.
2300 // Existing bindings just get "merged".
2301 let collected = bindings.pop().unwrap().1;
2302 bindings.last_mut().unwrap().1.extend(collected);
2304 // This or-pattern itself can itself be part of a product,
2305 // e.g. `(V1(a) | V2(a), a)` or `(a, V1(a) | V2(a))`.
2306 // Both cases bind `a` again in a product pattern and must be rejected.
2307 let collected = bindings.pop().unwrap().1;
2308 bindings.last_mut().unwrap().1.extend(collected);
2310 // Prevent visiting `ps` as we've already done so above.
2323 pat_src: PatternSource,
2324 bindings: &mut SmallVec<[(PatBoundCtx, FxHashSet<Ident>); 1]>,
2326 // Add the binding to the local ribs, if it doesn't already exist in the bindings map.
2327 // (We must not add it if it's in the bindings map because that breaks the assumptions
2328 // later passes make about or-patterns.)
2329 let ident = ident.normalize_to_macro_rules();
2331 let mut bound_iter = bindings.iter().filter(|(_, set)| set.contains(&ident));
2332 // Already bound in a product pattern? e.g. `(a, a)` which is not allowed.
2333 let already_bound_and = bound_iter.clone().any(|(ctx, _)| *ctx == PatBoundCtx::Product);
2334 // Already bound in an or-pattern? e.g. `V1(a) | V2(a)`.
2335 // This is *required* for consistency which is checked later.
2336 let already_bound_or = bound_iter.any(|(ctx, _)| *ctx == PatBoundCtx::Or);
2338 if already_bound_and {
2339 // Overlap in a product pattern somewhere; report an error.
2340 use ResolutionError::*;
2341 let error = match pat_src {
2342 // `fn f(a: u8, a: u8)`:
2343 PatternSource::FnParam => IdentifierBoundMoreThanOnceInParameterList,
2345 _ => IdentifierBoundMoreThanOnceInSamePattern,
2347 self.report_error(ident.span, error(ident.name));
2350 // Record as bound if it's valid:
2351 let ident_valid = ident.name != kw::Empty;
2353 bindings.last_mut().unwrap().1.insert(ident);
2356 if already_bound_or {
2357 // `Variant1(a) | Variant2(a)`, ok
2358 // Reuse definition from the first `a`.
2359 self.innermost_rib_bindings(ValueNS)[&ident]
2361 let res = Res::Local(pat_id);
2363 // A completely fresh binding add to the set if it's valid.
2364 self.innermost_rib_bindings(ValueNS).insert(ident, res);
2370 fn innermost_rib_bindings(&mut self, ns: Namespace) -> &mut IdentMap<Res> {
2371 &mut self.ribs[ns].last_mut().unwrap().bindings
2374 fn try_resolve_as_non_binding(
2376 pat_src: PatternSource,
2381 // An immutable (no `mut`) by-value (no `ref`) binding pattern without
2382 // a sub pattern (no `@ $pat`) is syntactically ambiguous as it could
2383 // also be interpreted as a path to e.g. a constant, variant, etc.
2384 let is_syntactic_ambiguity = !has_sub && bm == BindingMode::ByValue(Mutability::Not);
2386 let ls_binding = self.maybe_resolve_ident_in_lexical_scope(ident, ValueNS)?;
2387 let (res, binding) = match ls_binding {
2388 LexicalScopeBinding::Item(binding)
2389 if is_syntactic_ambiguity && binding.is_ambiguity() =>
2391 // For ambiguous bindings we don't know all their definitions and cannot check
2392 // whether they can be shadowed by fresh bindings or not, so force an error.
2393 // issues/33118#issuecomment-233962221 (see below) still applies here,
2394 // but we have to ignore it for backward compatibility.
2395 self.r.record_use(ident, binding, false);
2398 LexicalScopeBinding::Item(binding) => (binding.res(), Some(binding)),
2399 LexicalScopeBinding::Res(res) => (res, None),
2403 Res::SelfCtor(_) // See #70549.
2405 DefKind::Ctor(_, CtorKind::Const) | DefKind::Const | DefKind::ConstParam,
2407 ) if is_syntactic_ambiguity => {
2408 // Disambiguate in favor of a unit struct/variant or constant pattern.
2409 if let Some(binding) = binding {
2410 self.r.record_use(ident, binding, false);
2414 Res::Def(DefKind::Ctor(..) | DefKind::Const | DefKind::Static(_), _) => {
2415 // This is unambiguously a fresh binding, either syntactically
2416 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2417 // to something unusable as a pattern (e.g., constructor function),
2418 // but we still conservatively report an error, see
2419 // issues/33118#issuecomment-233962221 for one reason why.
2420 let binding = binding.expect("no binding for a ctor or static");
2423 ResolutionError::BindingShadowsSomethingUnacceptable {
2424 shadowing_binding_descr: pat_src.descr(),
2426 participle: if binding.is_import() { "imported" } else { "defined" },
2427 article: binding.res().article(),
2428 shadowed_binding_descr: binding.res().descr(),
2429 shadowed_binding_span: binding.span,
2434 Res::Def(DefKind::ConstParam, def_id) => {
2435 // Same as for DefKind::Const above, but here, `binding` is `None`, so we
2436 // have to construct the error differently
2439 ResolutionError::BindingShadowsSomethingUnacceptable {
2440 shadowing_binding_descr: pat_src.descr(),
2442 participle: "defined",
2443 article: res.article(),
2444 shadowed_binding_descr: res.descr(),
2445 shadowed_binding_span: self.r.opt_span(def_id).expect("const parameter defined outside of local crate"),
2450 Res::Def(DefKind::Fn, _) | Res::Local(..) | Res::Err => {
2451 // These entities are explicitly allowed to be shadowed by fresh bindings.
2454 Res::SelfCtor(_) => {
2455 // We resolve `Self` in pattern position as an ident sometimes during recovery,
2456 // so delay a bug instead of ICEing.
2457 self.r.session.delay_span_bug(
2459 "unexpected `SelfCtor` in pattern, expected identifier"
2465 "unexpected resolution for an identifier in pattern: {:?}",
2471 // High-level and context dependent path resolution routine.
2472 // Resolves the path and records the resolution into definition map.
2473 // If resolution fails tries several techniques to find likely
2474 // resolution candidates, suggest imports or other help, and report
2475 // errors in user friendly way.
2476 fn smart_resolve_path(
2479 qself: Option<&QSelf>,
2481 source: PathSource<'ast>,
2483 self.smart_resolve_path_fragment(
2485 &Segment::from_path(path),
2487 Finalize::SimplePath(id, path.span),
2491 fn smart_resolve_path_fragment(
2493 qself: Option<&QSelf>,
2495 source: PathSource<'ast>,
2499 "smart_resolve_path_fragment(qself={:?}, path={:?}, finalize={:?})",
2504 let ns = source.namespace();
2506 let (id, path_span) =
2507 finalize.node_id_and_path_span().expect("unexpected speculative resolution");
2508 let report_errors = |this: &mut Self, res: Option<Res>| {
2509 if this.should_report_errs() {
2510 let (err, candidates) =
2511 this.smart_resolve_report_errors(path, path_span, source, res);
2513 let def_id = this.parent_scope.module.nearest_parent_mod();
2514 let instead = res.is_some();
2516 if res.is_none() { this.report_missing_type_error(path) } else { None };
2518 this.r.use_injections.push(UseError {
2527 PartialRes::new(Res::Err)
2530 // For paths originating from calls (like in `HashMap::new()`), tries
2531 // to enrich the plain `failed to resolve: ...` message with hints
2532 // about possible missing imports.
2534 // Similar thing, for types, happens in `report_errors` above.
2535 let report_errors_for_call = |this: &mut Self, parent_err: Spanned<ResolutionError<'a>>| {
2536 if !source.is_call() {
2537 return Some(parent_err);
2540 // Before we start looking for candidates, we have to get our hands
2541 // on the type user is trying to perform invocation on; basically:
2542 // we're transforming `HashMap::new` into just `HashMap`.
2543 let path = match path.split_last() {
2544 Some((_, path)) if !path.is_empty() => path,
2545 _ => return Some(parent_err),
2548 let (mut err, candidates) =
2549 this.smart_resolve_report_errors(path, path_span, PathSource::Type, None);
2551 if candidates.is_empty() {
2553 return Some(parent_err);
2556 // There are two different error messages user might receive at
2558 // - E0412 cannot find type `{}` in this scope
2559 // - E0433 failed to resolve: use of undeclared type or module `{}`
2561 // The first one is emitted for paths in type-position, and the
2562 // latter one - for paths in expression-position.
2564 // Thus (since we're in expression-position at this point), not to
2565 // confuse the user, we want to keep the *message* from E0432 (so
2566 // `parent_err`), but we want *hints* from E0412 (so `err`).
2568 // And that's what happens below - we're just mixing both messages
2569 // into a single one.
2570 let mut parent_err = this.r.into_struct_error(parent_err.span, parent_err.node);
2572 err.message = take(&mut parent_err.message);
2573 err.code = take(&mut parent_err.code);
2574 err.children = take(&mut parent_err.children);
2576 parent_err.cancel();
2578 let def_id = this.parent_scope.module.nearest_parent_mod();
2580 if this.should_report_errs() {
2581 this.r.use_injections.push(UseError {
2592 // We don't return `Some(parent_err)` here, because the error will
2593 // be already printed as part of the `use` injections
2597 let partial_res = match self.resolve_qpath_anywhere(
2602 source.defer_to_typeck(),
2605 Ok(Some(partial_res)) if partial_res.unresolved_segments() == 0 => {
2606 if source.is_expected(partial_res.base_res()) || partial_res.base_res() == Res::Err
2610 report_errors(self, Some(partial_res.base_res()))
2614 Ok(Some(partial_res)) if source.defer_to_typeck() => {
2615 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2616 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2617 // it needs to be added to the trait map.
2619 let item_name = path.last().unwrap().ident;
2620 let traits = self.traits_in_scope(item_name, ns);
2621 self.r.trait_map.insert(id, traits);
2624 if PrimTy::from_name(path[0].ident.name).is_some() {
2625 let mut std_path = Vec::with_capacity(1 + path.len());
2627 std_path.push(Segment::from_ident(Ident::with_dummy_span(sym::std)));
2628 std_path.extend(path);
2629 if let PathResult::Module(_) | PathResult::NonModule(_) =
2630 self.resolve_path(&std_path, Some(ns), Finalize::No)
2632 // Check if we wrote `str::from_utf8` instead of `std::str::from_utf8`
2634 path.iter().last().map_or(path_span, |segment| segment.ident.span);
2636 self.r.confused_type_with_std_module.insert(item_span, path_span);
2637 self.r.confused_type_with_std_module.insert(path_span, path_span);
2645 if let Some(err) = report_errors_for_call(self, err) {
2646 self.report_error(err.span, err.node);
2649 PartialRes::new(Res::Err)
2652 _ => report_errors(self, None),
2655 if !matches!(source, PathSource::TraitItem(..)) {
2656 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2657 self.r.record_partial_res(id, partial_res);
2660 self.resolve_elided_lifetimes_in_path(id, partial_res, path, source, finalize);
2664 fn self_type_is_available(&mut self) -> bool {
2666 .maybe_resolve_ident_in_lexical_scope(Ident::with_dummy_span(kw::SelfUpper), TypeNS);
2667 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
2670 fn self_value_is_available(&mut self, self_span: Span) -> bool {
2671 let ident = Ident::new(kw::SelfLower, self_span);
2672 let binding = self.maybe_resolve_ident_in_lexical_scope(ident, ValueNS);
2673 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
2676 /// A wrapper around [`Resolver::report_error`].
2678 /// This doesn't emit errors for function bodies if this is rustdoc.
2679 fn report_error(&self, span: Span, resolution_error: ResolutionError<'_>) {
2680 if self.should_report_errs() {
2681 self.r.report_error(span, resolution_error);
2686 /// If we're actually rustdoc then avoid giving a name resolution error for `cfg()` items.
2687 fn should_report_errs(&self) -> bool {
2688 !(self.r.session.opts.actually_rustdoc && self.in_func_body)
2691 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2692 fn resolve_qpath_anywhere(
2694 qself: Option<&QSelf>,
2696 primary_ns: Namespace,
2698 defer_to_typeck: bool,
2700 ) -> Result<Option<PartialRes>, Spanned<ResolutionError<'a>>> {
2701 let mut fin_res = None;
2703 for (i, &ns) in [primary_ns, TypeNS, ValueNS].iter().enumerate() {
2704 if i == 0 || ns != primary_ns {
2705 match self.resolve_qpath(qself, path, ns, finalize)? {
2707 if partial_res.unresolved_segments() == 0 || defer_to_typeck =>
2709 return Ok(Some(partial_res));
2712 if fin_res.is_none() {
2713 fin_res = partial_res;
2720 assert!(primary_ns != MacroNS);
2722 if qself.is_none() {
2723 let path_seg = |seg: &Segment| PathSegment::from_ident(seg.ident);
2724 let path = Path { segments: path.iter().map(path_seg).collect(), span, tokens: None };
2725 if let Ok((_, res)) =
2726 self.r.resolve_macro_path(&path, None, &self.parent_scope, false, false)
2728 return Ok(Some(PartialRes::new(res)));
2735 /// Handles paths that may refer to associated items.
2738 qself: Option<&QSelf>,
2742 ) -> Result<Option<PartialRes>, Spanned<ResolutionError<'a>>> {
2744 "resolve_qpath(qself={:?}, path={:?}, ns={:?}, finalize={:?})",
2745 qself, path, ns, finalize,
2748 if let Some(qself) = qself {
2749 if qself.position == 0 {
2750 // This is a case like `<T>::B`, where there is no
2751 // trait to resolve. In that case, we leave the `B`
2752 // segment to be resolved by type-check.
2753 return Ok(Some(PartialRes::with_unresolved_segments(
2754 Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id()),
2759 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
2761 // Currently, `path` names the full item (`A::B::C`, in
2762 // our example). so we extract the prefix of that that is
2763 // the trait (the slice upto and including
2764 // `qself.position`). And then we recursively resolve that,
2765 // but with `qself` set to `None`.
2767 // However, setting `qself` to none (but not changing the
2768 // span) loses the information about where this path
2769 // *actually* appears, so for the purposes of the crate
2770 // lint we pass along information that this is the trait
2771 // name from a fully qualified path, and this also
2772 // contains the full span (the `Finalize::QPathTrait`).
2773 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2774 let partial_res = self.smart_resolve_path_fragment(
2776 &path[..=qself.position],
2777 PathSource::TraitItem(ns),
2778 finalize.node_id_and_path_span().map_or(Finalize::No, |(qpath_id, path_span)| {
2779 Finalize::QPathTrait { qpath_id, qpath_span: qself.path_span, path_span }
2783 // The remaining segments (the `C` in our example) will
2784 // have to be resolved by type-check, since that requires doing
2785 // trait resolution.
2786 return Ok(Some(PartialRes::with_unresolved_segments(
2787 partial_res.base_res(),
2788 partial_res.unresolved_segments() + path.len() - qself.position - 1,
2792 let result = match self.resolve_path(&path, Some(ns), finalize) {
2793 PathResult::NonModule(path_res) => path_res,
2794 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
2795 PartialRes::new(module.res().unwrap())
2797 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2798 // don't report an error right away, but try to fallback to a primitive type.
2799 // So, we are still able to successfully resolve something like
2801 // use std::u8; // bring module u8 in scope
2802 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2803 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2804 // // not to non-existent std::u8::max_value
2807 // Such behavior is required for backward compatibility.
2808 // The same fallback is used when `a` resolves to nothing.
2809 PathResult::Module(ModuleOrUniformRoot::Module(_)) | PathResult::Failed { .. }
2810 if (ns == TypeNS || path.len() > 1)
2811 && PrimTy::from_name(path[0].ident.name).is_some() =>
2813 let prim = PrimTy::from_name(path[0].ident.name).unwrap();
2814 PartialRes::with_unresolved_segments(Res::PrimTy(prim), path.len() - 1)
2816 PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
2817 PartialRes::new(module.res().unwrap())
2819 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
2820 return Err(respan(span, ResolutionError::FailedToResolve { label, suggestion }));
2822 PathResult::Module(..) | PathResult::Failed { .. } => return Ok(None),
2823 PathResult::Indeterminate => bug!("indeterminate path result in resolve_qpath"),
2827 && result.base_res() != Res::Err
2828 && path[0].ident.name != kw::PathRoot
2829 && path[0].ident.name != kw::DollarCrate
2830 && let Some((id, path_span)) = finalize.node_id_and_path_span()
2832 let unqualified_result = {
2833 match self.resolve_path(&[*path.last().unwrap()], Some(ns), Finalize::No) {
2834 PathResult::NonModule(path_res) => path_res.base_res(),
2835 PathResult::Module(ModuleOrUniformRoot::Module(module)) => {
2836 module.res().unwrap()
2838 _ => return Ok(Some(result)),
2841 if result.base_res() == unqualified_result {
2842 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2843 self.r.lint_buffer.buffer_lint(lint, id, path_span, "unnecessary qualification")
2850 fn with_resolved_label(&mut self, label: Option<Label>, id: NodeId, f: impl FnOnce(&mut Self)) {
2851 if let Some(label) = label {
2852 if label.ident.as_str().as_bytes()[1] != b'_' {
2853 self.diagnostic_metadata.unused_labels.insert(id, label.ident.span);
2855 self.with_label_rib(NormalRibKind, |this| {
2856 let ident = label.ident.normalize_to_macro_rules();
2857 this.label_ribs.last_mut().unwrap().bindings.insert(ident, id);
2865 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &'ast Block) {
2866 self.with_resolved_label(label, id, |this| this.visit_block(block));
2869 fn resolve_block(&mut self, block: &'ast Block) {
2870 debug!("(resolving block) entering block");
2871 // Move down in the graph, if there's an anonymous module rooted here.
2872 let orig_module = self.parent_scope.module;
2873 let anonymous_module = self.r.block_map.get(&block.id).cloned(); // clones a reference
2875 let mut num_macro_definition_ribs = 0;
2876 if let Some(anonymous_module) = anonymous_module {
2877 debug!("(resolving block) found anonymous module, moving down");
2878 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2879 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2880 self.parent_scope.module = anonymous_module;
2882 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2885 let prev = self.diagnostic_metadata.current_block_could_be_bare_struct_literal.take();
2886 if let (true, [Stmt { kind: StmtKind::Expr(expr), .. }]) =
2887 (block.could_be_bare_literal, &block.stmts[..])
2888 && let ExprKind::Type(..) = expr.kind
2890 self.diagnostic_metadata.current_block_could_be_bare_struct_literal =
2893 // Descend into the block.
2894 for stmt in &block.stmts {
2895 if let StmtKind::Item(ref item) = stmt.kind
2896 && let ItemKind::MacroDef(..) = item.kind {
2897 num_macro_definition_ribs += 1;
2898 let res = self.r.local_def_id(item.id).to_def_id();
2899 self.ribs[ValueNS].push(Rib::new(MacroDefinition(res)));
2900 self.label_ribs.push(Rib::new(MacroDefinition(res)));
2903 self.visit_stmt(stmt);
2905 self.diagnostic_metadata.current_block_could_be_bare_struct_literal = prev;
2908 self.parent_scope.module = orig_module;
2909 for _ in 0..num_macro_definition_ribs {
2910 self.ribs[ValueNS].pop();
2911 self.label_ribs.pop();
2913 self.ribs[ValueNS].pop();
2914 if anonymous_module.is_some() {
2915 self.ribs[TypeNS].pop();
2917 debug!("(resolving block) leaving block");
2920 fn resolve_anon_const(&mut self, constant: &'ast AnonConst, is_repeat: IsRepeatExpr) {
2921 debug!("resolve_anon_const {:?} is_repeat: {:?}", constant, is_repeat);
2922 self.with_constant_rib(
2924 constant.value.is_potential_trivial_const_param(),
2927 visit::walk_anon_const(this, constant);
2932 fn resolve_expr(&mut self, expr: &'ast Expr, parent: Option<&'ast Expr>) {
2933 // First, record candidate traits for this expression if it could
2934 // result in the invocation of a method call.
2936 self.record_candidate_traits_for_expr_if_necessary(expr);
2938 // Next, resolve the node.
2940 ExprKind::Path(ref qself, ref path) => {
2941 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
2942 visit::walk_expr(self, expr);
2945 ExprKind::Struct(ref se) => {
2946 self.smart_resolve_path(expr.id, se.qself.as_ref(), &se.path, PathSource::Struct);
2947 visit::walk_expr(self, expr);
2950 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
2951 if let Some(node_id) = self.resolve_label(label.ident) {
2952 // Since this res is a label, it is never read.
2953 self.r.label_res_map.insert(expr.id, node_id);
2954 self.diagnostic_metadata.unused_labels.remove(&node_id);
2957 // visit `break` argument if any
2958 visit::walk_expr(self, expr);
2961 ExprKind::Break(None, Some(ref e)) => {
2962 // We use this instead of `visit::walk_expr` to keep the parent expr around for
2963 // better diagnostics.
2964 self.resolve_expr(e, Some(&expr));
2967 ExprKind::Let(ref pat, ref scrutinee, _) => {
2968 self.visit_expr(scrutinee);
2969 self.resolve_pattern_top(pat, PatternSource::Let);
2972 ExprKind::If(ref cond, ref then, ref opt_else) => {
2973 self.with_rib(ValueNS, NormalRibKind, |this| {
2974 let old = this.diagnostic_metadata.in_if_condition.replace(cond);
2975 this.visit_expr(cond);
2976 this.diagnostic_metadata.in_if_condition = old;
2977 this.visit_block(then);
2979 if let Some(expr) = opt_else {
2980 self.visit_expr(expr);
2984 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
2986 ExprKind::While(ref cond, ref block, label) => {
2987 self.with_resolved_label(label, expr.id, |this| {
2988 this.with_rib(ValueNS, NormalRibKind, |this| {
2989 let old = this.diagnostic_metadata.in_if_condition.replace(cond);
2990 this.visit_expr(cond);
2991 this.diagnostic_metadata.in_if_condition = old;
2992 this.visit_block(block);
2997 ExprKind::ForLoop(ref pat, ref iter_expr, ref block, label) => {
2998 self.visit_expr(iter_expr);
2999 self.with_rib(ValueNS, NormalRibKind, |this| {
3000 this.resolve_pattern_top(pat, PatternSource::For);
3001 this.resolve_labeled_block(label, expr.id, block);
3005 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
3007 // Equivalent to `visit::walk_expr` + passing some context to children.
3008 ExprKind::Field(ref subexpression, _) => {
3009 self.resolve_expr(subexpression, Some(expr));
3011 ExprKind::MethodCall(ref segment, ref arguments, _) => {
3012 let mut arguments = arguments.iter();
3013 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3014 for argument in arguments {
3015 self.resolve_expr(argument, None);
3017 self.visit_path_segment(expr.span, segment);
3020 ExprKind::Call(ref callee, ref arguments) => {
3021 self.resolve_expr(callee, Some(expr));
3022 let const_args = self.r.legacy_const_generic_args(callee).unwrap_or_default();
3023 for (idx, argument) in arguments.iter().enumerate() {
3024 // Constant arguments need to be treated as AnonConst since
3025 // that is how they will be later lowered to HIR.
3026 if const_args.contains(&idx) {
3027 self.with_constant_rib(
3029 argument.is_potential_trivial_const_param(),
3032 this.resolve_expr(argument, None);
3036 self.resolve_expr(argument, None);
3040 ExprKind::Type(ref type_expr, ref ty) => {
3041 // `ParseSess::type_ascription_path_suggestions` keeps spans of colon tokens in
3042 // type ascription. Here we are trying to retrieve the span of the colon token as
3043 // well, but only if it's written without spaces `expr:Ty` and therefore confusable
3044 // with `expr::Ty`, only in this case it will match the span from
3045 // `type_ascription_path_suggestions`.
3046 self.diagnostic_metadata
3047 .current_type_ascription
3048 .push(type_expr.span.between(ty.span));
3049 visit::walk_expr(self, expr);
3050 self.diagnostic_metadata.current_type_ascription.pop();
3052 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
3053 // resolve the arguments within the proper scopes so that usages of them inside the
3054 // closure are detected as upvars rather than normal closure arg usages.
3055 ExprKind::Closure(_, Async::Yes { .. }, _, ref fn_decl, ref body, _span) => {
3056 self.with_rib(ValueNS, NormalRibKind, |this| {
3057 this.with_label_rib(ClosureOrAsyncRibKind, |this| {
3058 // Resolve arguments:
3059 this.resolve_params(&fn_decl.inputs);
3060 // No need to resolve return type --
3061 // the outer closure return type is `FnRetTy::Default`.
3063 // Now resolve the inner closure
3065 // No need to resolve arguments: the inner closure has none.
3066 // Resolve the return type:
3067 visit::walk_fn_ret_ty(this, &fn_decl.output);
3069 this.visit_expr(body);
3074 ExprKind::Async(..) | ExprKind::Closure(..) => {
3075 self.with_label_rib(ClosureOrAsyncRibKind, |this| visit::walk_expr(this, expr));
3077 ExprKind::Repeat(ref elem, ref ct) => {
3078 self.visit_expr(elem);
3079 self.resolve_anon_const(ct, IsRepeatExpr::Yes);
3081 ExprKind::Index(ref elem, ref idx) => {
3082 self.resolve_expr(elem, Some(expr));
3083 self.visit_expr(idx);
3086 visit::walk_expr(self, expr);
3091 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &'ast Expr) {
3093 ExprKind::Field(_, ident) => {
3094 // FIXME(#6890): Even though you can't treat a method like a
3095 // field, we need to add any trait methods we find that match
3096 // the field name so that we can do some nice error reporting
3097 // later on in typeck.
3098 let traits = self.traits_in_scope(ident, ValueNS);
3099 self.r.trait_map.insert(expr.id, traits);
3101 ExprKind::MethodCall(ref segment, ..) => {
3102 debug!("(recording candidate traits for expr) recording traits for {}", expr.id);
3103 let traits = self.traits_in_scope(segment.ident, ValueNS);
3104 self.r.trait_map.insert(expr.id, traits);
3112 fn traits_in_scope(&mut self, ident: Ident, ns: Namespace) -> Vec<TraitCandidate> {
3113 self.r.traits_in_scope(
3114 self.current_trait_ref.as_ref().map(|(module, _)| *module),
3117 Some((ident.name, ns)),
3122 struct LifetimeCountVisitor<'a, 'b> {
3123 r: &'b mut Resolver<'a>,
3126 /// Walks the whole crate in DFS order, visiting each item, counting the declared number of
3127 /// lifetime generic parameters.
3128 impl<'ast> Visitor<'ast> for LifetimeCountVisitor<'_, '_> {
3129 fn visit_item(&mut self, item: &'ast Item) {
3131 ItemKind::TyAlias(box TyAlias { ref generics, .. })
3132 | ItemKind::Fn(box Fn { ref generics, .. })
3133 | ItemKind::Enum(_, ref generics)
3134 | ItemKind::Struct(_, ref generics)
3135 | ItemKind::Union(_, ref generics)
3136 | ItemKind::Impl(box Impl { ref generics, .. })
3137 | ItemKind::Trait(box Trait { ref generics, .. })
3138 | ItemKind::TraitAlias(ref generics, _) => {
3139 let def_id = self.r.local_def_id(item.id);
3140 let count = generics
3143 .filter(|param| matches!(param.kind, ast::GenericParamKind::Lifetime { .. }))
3145 self.r.item_generics_num_lifetimes.insert(def_id, count);
3149 | ItemKind::ForeignMod(..)
3150 | ItemKind::Static(..)
3151 | ItemKind::Const(..)
3153 | ItemKind::ExternCrate(..)
3154 | ItemKind::MacroDef(..)
3155 | ItemKind::GlobalAsm(..)
3156 | ItemKind::MacCall(..) => {}
3158 visit::walk_item(self, item)
3162 impl<'a> Resolver<'a> {
3163 pub(crate) fn late_resolve_crate(&mut self, krate: &Crate) {
3164 visit::walk_crate(&mut LifetimeCountVisitor { r: self }, krate);
3165 let mut late_resolution_visitor = LateResolutionVisitor::new(self);
3166 visit::walk_crate(&mut late_resolution_visitor, krate);
3167 for (id, span) in late_resolution_visitor.diagnostic_metadata.unused_labels.iter() {
3168 self.lint_buffer.buffer_lint(lint::builtin::UNUSED_LABELS, *id, *span, "unused label");
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