1 // ignore-tidy-filelength
3 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
5 #![feature(crate_visibility_modifier)]
6 #![feature(label_break_value)]
8 #![feature(rustc_diagnostic_macros)]
9 #![feature(type_alias_enum_variants)]
11 #![recursion_limit="256"]
13 #![deny(rust_2018_idioms)]
16 pub use rustc::hir::def::{Namespace, PerNS};
18 use GenericParameters::*;
20 use smallvec::smallvec;
22 use rustc::hir::map::{Definitions, DefCollector};
23 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
24 use rustc::middle::cstore::CrateStore;
25 use rustc::session::Session;
27 use rustc::hir::def::{
28 self, DefKind, PartialRes, CtorKind, CtorOf, NonMacroAttrKind, ExportMap
30 use rustc::hir::def::Namespace::*;
31 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
32 use rustc::hir::{TraitCandidate, TraitMap, GlobMap};
33 use rustc::ty::{self, DefIdTree};
34 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
35 use rustc::{bug, span_bug};
37 use rustc_metadata::creader::CrateLoader;
38 use rustc_metadata::cstore::CStore;
40 use syntax::source_map::SourceMap;
41 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
42 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
43 use syntax::ext::base::SyntaxExtension;
44 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
45 use syntax::ext::base::MacroKind;
46 use syntax::symbol::{Symbol, kw, sym};
47 use syntax::util::lev_distance::find_best_match_for_name;
49 use syntax::visit::{self, FnKind, Visitor};
51 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
52 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
53 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
54 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
55 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
57 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
59 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
60 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
64 use std::cell::{Cell, RefCell};
65 use std::{cmp, fmt, iter, mem, ptr};
66 use std::collections::BTreeSet;
67 use std::mem::replace;
68 use rustc_data_structures::ptr_key::PtrKey;
69 use rustc_data_structures::sync::Lrc;
70 use smallvec::SmallVec;
72 use diagnostics::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
73 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
74 use macros::{InvocationData, LegacyBinding, ParentScope};
76 type Res = def::Res<NodeId>;
78 // N.B., this module needs to be declared first so diagnostics are
79 // registered before they are used.
84 mod build_reduced_graph;
87 fn is_known_tool(name: Name) -> bool {
88 ["clippy", "rustfmt"].contains(&&*name.as_str())
98 AbsolutePath(Namespace),
103 /// A free importable items suggested in case of resolution failure.
104 struct ImportSuggestion {
109 /// A field or associated item from self type suggested in case of resolution failure.
110 enum AssocSuggestion {
117 struct BindingError {
119 origin: BTreeSet<Span>,
120 target: BTreeSet<Span>,
123 struct TypoSuggestion {
126 /// The kind of the binding ("crate", "module", etc.)
129 /// An appropriate article to refer to the binding ("a", "an", etc.)
130 article: &'static str,
133 impl PartialOrd for BindingError {
134 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
135 Some(self.cmp(other))
139 impl PartialEq for BindingError {
140 fn eq(&self, other: &BindingError) -> bool {
141 self.name == other.name
145 impl Ord for BindingError {
146 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
147 self.name.cmp(&other.name)
151 /// A vector of spans and replacements, a message and applicability.
152 type Suggestion = (Vec<(Span, String)>, String, Applicability);
154 enum ResolutionError<'a> {
155 /// Error E0401: can't use type or const parameters from outer function.
156 GenericParamsFromOuterFunction(Res),
157 /// Error E0403: the name is already used for a type or const parameter in this generic
159 NameAlreadyUsedInParameterList(Name, &'a Span),
160 /// Error E0407: method is not a member of trait.
161 MethodNotMemberOfTrait(Name, &'a str),
162 /// Error E0437: type is not a member of trait.
163 TypeNotMemberOfTrait(Name, &'a str),
164 /// Error E0438: const is not a member of trait.
165 ConstNotMemberOfTrait(Name, &'a str),
166 /// Error E0408: variable `{}` is not bound in all patterns.
167 VariableNotBoundInPattern(&'a BindingError),
168 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
169 VariableBoundWithDifferentMode(Name, Span),
170 /// Error E0415: identifier is bound more than once in this parameter list.
171 IdentifierBoundMoreThanOnceInParameterList(&'a str),
172 /// Error E0416: identifier is bound more than once in the same pattern.
173 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
174 /// Error E0426: use of undeclared label.
175 UndeclaredLabel(&'a str, Option<Name>),
176 /// Error E0429: `self` imports are only allowed within a `{ }` list.
177 SelfImportsOnlyAllowedWithin,
178 /// Error E0430: `self` import can only appear once in the list.
179 SelfImportCanOnlyAppearOnceInTheList,
180 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
181 SelfImportOnlyInImportListWithNonEmptyPrefix,
182 /// Error E0433: failed to resolve.
183 FailedToResolve { label: String, suggestion: Option<Suggestion> },
184 /// Error E0434: can't capture dynamic environment in a fn item.
185 CannotCaptureDynamicEnvironmentInFnItem,
186 /// Error E0435: attempt to use a non-constant value in a constant.
187 AttemptToUseNonConstantValueInConstant,
188 /// Error E0530: `X` bindings cannot shadow `Y`s.
189 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
190 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
191 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
192 /// Error E0671: const parameter cannot depend on type parameter.
193 ConstParamDependentOnTypeParam,
196 /// Combines an error with provided span and emits it.
198 /// This takes the error provided, combines it with the span and any additional spans inside the
199 /// error and emits it.
200 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
202 resolution_error: ResolutionError<'a>) {
203 resolve_struct_error(resolver, span, resolution_error).emit();
206 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
208 resolution_error: ResolutionError<'a>)
209 -> DiagnosticBuilder<'sess> {
210 match resolution_error {
211 ResolutionError::GenericParamsFromOuterFunction(outer_res) => {
212 let mut err = struct_span_err!(resolver.session,
215 "can't use generic parameters from outer function",
217 err.span_label(span, format!("use of generic parameter from outer function"));
219 let cm = resolver.session.source_map();
221 Res::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
222 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
223 resolver.definitions.opt_span(def_id)
226 reduce_impl_span_to_impl_keyword(cm, impl_span),
227 "`Self` type implicitly declared here, by this `impl`",
230 match (maybe_trait_defid, maybe_impl_defid) {
232 err.span_label(span, "can't use `Self` here");
235 err.span_label(span, "use a type here instead");
237 (None, None) => bug!("`impl` without trait nor type?"),
241 Res::Def(DefKind::TyParam, def_id) => {
242 if let Some(span) = resolver.definitions.opt_span(def_id) {
243 err.span_label(span, "type parameter from outer function");
246 Res::Def(DefKind::ConstParam, def_id) => {
247 if let Some(span) = resolver.definitions.opt_span(def_id) {
248 err.span_label(span, "const parameter from outer function");
252 bug!("GenericParamsFromOuterFunction should only be used with Res::SelfTy, \
257 // Try to retrieve the span of the function signature and generate a new message with
258 // a local type or const parameter.
259 let sugg_msg = &format!("try using a local generic parameter instead");
260 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
261 // Suggest the modification to the user
266 Applicability::MachineApplicable,
268 } else if let Some(sp) = cm.generate_fn_name_span(span) {
270 format!("try adding a local generic parameter in this method instead"));
272 err.help(&format!("try using a local generic parameter instead"));
277 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
278 let mut err = struct_span_err!(resolver.session,
281 "the name `{}` is already used for a generic \
282 parameter in this list of generic parameters",
284 err.span_label(span, "already used");
285 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
288 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
289 let mut err = struct_span_err!(resolver.session,
292 "method `{}` is not a member of trait `{}`",
295 err.span_label(span, format!("not a member of trait `{}`", trait_));
298 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
299 let mut err = struct_span_err!(resolver.session,
302 "type `{}` is not a member of trait `{}`",
305 err.span_label(span, format!("not a member of trait `{}`", trait_));
308 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
309 let mut err = struct_span_err!(resolver.session,
312 "const `{}` is not a member of trait `{}`",
315 err.span_label(span, format!("not a member of trait `{}`", trait_));
318 ResolutionError::VariableNotBoundInPattern(binding_error) => {
319 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
320 let msp = MultiSpan::from_spans(target_sp.clone());
321 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
322 let mut err = resolver.session.struct_span_err_with_code(
325 DiagnosticId::Error("E0408".into()),
327 for sp in target_sp {
328 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
330 let origin_sp = binding_error.origin.iter().cloned();
331 for sp in origin_sp {
332 err.span_label(sp, "variable not in all patterns");
336 ResolutionError::VariableBoundWithDifferentMode(variable_name,
337 first_binding_span) => {
338 let mut err = struct_span_err!(resolver.session,
341 "variable `{}` is bound in inconsistent \
342 ways within the same match arm",
344 err.span_label(span, "bound in different ways");
345 err.span_label(first_binding_span, "first binding");
348 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
349 let mut err = struct_span_err!(resolver.session,
352 "identifier `{}` is bound more than once in this parameter list",
354 err.span_label(span, "used as parameter more than once");
357 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
358 let mut err = struct_span_err!(resolver.session,
361 "identifier `{}` is bound more than once in the same pattern",
363 err.span_label(span, "used in a pattern more than once");
366 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
367 let mut err = struct_span_err!(resolver.session,
370 "use of undeclared label `{}`",
372 if let Some(lev_candidate) = lev_candidate {
375 "a label with a similar name exists in this scope",
376 lev_candidate.to_string(),
377 Applicability::MaybeIncorrect,
380 err.span_label(span, format!("undeclared label `{}`", name));
384 ResolutionError::SelfImportsOnlyAllowedWithin => {
385 struct_span_err!(resolver.session,
389 "`self` imports are only allowed within a { } list")
391 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
392 let mut err = struct_span_err!(resolver.session, span, E0430,
393 "`self` import can only appear once in an import list");
394 err.span_label(span, "can only appear once in an import list");
397 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
398 let mut err = struct_span_err!(resolver.session, span, E0431,
399 "`self` import can only appear in an import list with \
400 a non-empty prefix");
401 err.span_label(span, "can only appear in an import list with a non-empty prefix");
404 ResolutionError::FailedToResolve { label, suggestion } => {
405 let mut err = struct_span_err!(resolver.session, span, E0433,
406 "failed to resolve: {}", &label);
407 err.span_label(span, label);
409 if let Some((suggestions, msg, applicability)) = suggestion {
410 err.multipart_suggestion(&msg, suggestions, applicability);
415 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
416 let mut err = struct_span_err!(resolver.session,
420 "can't capture dynamic environment in a fn item");
421 err.help("use the `|| { ... }` closure form instead");
424 ResolutionError::AttemptToUseNonConstantValueInConstant => {
425 let mut err = struct_span_err!(resolver.session, span, E0435,
426 "attempt to use a non-constant value in a constant");
427 err.span_label(span, "non-constant value");
430 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
431 let shadows_what = binding.descr();
432 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
433 what_binding, shadows_what);
434 err.span_label(span, format!("cannot be named the same as {} {}",
435 binding.article(), shadows_what));
436 let participle = if binding.is_import() { "imported" } else { "defined" };
437 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
438 err.span_label(binding.span, msg);
441 ResolutionError::ForwardDeclaredTyParam => {
442 let mut err = struct_span_err!(resolver.session, span, E0128,
443 "type parameters with a default cannot use \
444 forward declared identifiers");
446 span, "defaulted type parameters cannot be forward declared".to_string());
449 ResolutionError::ConstParamDependentOnTypeParam => {
450 let mut err = struct_span_err!(
454 "const parameters cannot depend on type parameters"
456 err.span_label(span, format!("const parameter depends on type parameter"));
462 /// Adjust the impl span so that just the `impl` keyword is taken by removing
463 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
464 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
466 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
467 /// parser. If you need to use this function or something similar, please consider updating the
468 /// `source_map` functions and this function to something more robust.
469 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
470 let impl_span = cm.span_until_char(impl_span, '<');
471 let impl_span = cm.span_until_whitespace(impl_span);
475 #[derive(Copy, Clone, Debug)]
478 binding_mode: BindingMode,
481 /// Map from the name in a pattern to its binding mode.
482 type BindingMap = FxHashMap<Ident, BindingInfo>;
484 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
495 fn descr(self) -> &'static str {
497 PatternSource::Match => "match binding",
498 PatternSource::IfLet => "if let binding",
499 PatternSource::WhileLet => "while let binding",
500 PatternSource::Let => "let binding",
501 PatternSource::For => "for binding",
502 PatternSource::FnParam => "function parameter",
507 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
508 enum AliasPossibility {
513 #[derive(Copy, Clone, Debug)]
514 enum PathSource<'a> {
515 // Type paths `Path`.
517 // Trait paths in bounds or impls.
518 Trait(AliasPossibility),
519 // Expression paths `path`, with optional parent context.
520 Expr(Option<&'a Expr>),
521 // Paths in path patterns `Path`.
523 // Paths in struct expressions and patterns `Path { .. }`.
525 // Paths in tuple struct patterns `Path(..)`.
527 // `m::A::B` in `<T as m::A>::B::C`.
528 TraitItem(Namespace),
529 // Path in `pub(path)`
533 impl<'a> PathSource<'a> {
534 fn namespace(self) -> Namespace {
536 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
537 PathSource::Visibility => TypeNS,
538 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
539 PathSource::TraitItem(ns) => ns,
543 fn global_by_default(self) -> bool {
545 PathSource::Visibility => true,
546 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
547 PathSource::Struct | PathSource::TupleStruct |
548 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
552 fn defer_to_typeck(self) -> bool {
554 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
555 PathSource::Struct | PathSource::TupleStruct => true,
556 PathSource::Trait(_) | PathSource::TraitItem(..) |
557 PathSource::Visibility => false,
561 fn descr_expected(self) -> &'static str {
563 PathSource::Type => "type",
564 PathSource::Trait(_) => "trait",
565 PathSource::Pat => "unit struct/variant or constant",
566 PathSource::Struct => "struct, variant or union type",
567 PathSource::TupleStruct => "tuple struct/variant",
568 PathSource::Visibility => "module",
569 PathSource::TraitItem(ns) => match ns {
570 TypeNS => "associated type",
571 ValueNS => "method or associated constant",
572 MacroNS => bug!("associated macro"),
574 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
575 // "function" here means "anything callable" rather than `DefKind::Fn`,
576 // this is not precise but usually more helpful than just "value".
577 Some(&ExprKind::Call(..)) => "function",
583 fn is_expected(self, res: Res) -> bool {
585 PathSource::Type => match res {
586 Res::Def(DefKind::Struct, _)
587 | Res::Def(DefKind::Union, _)
588 | Res::Def(DefKind::Enum, _)
589 | Res::Def(DefKind::Trait, _)
590 | Res::Def(DefKind::TraitAlias, _)
591 | Res::Def(DefKind::TyAlias, _)
592 | Res::Def(DefKind::AssocTy, _)
594 | Res::Def(DefKind::TyParam, _)
596 | Res::Def(DefKind::Existential, _)
597 | Res::Def(DefKind::ForeignTy, _) => true,
600 PathSource::Trait(AliasPossibility::No) => match res {
601 Res::Def(DefKind::Trait, _) => true,
604 PathSource::Trait(AliasPossibility::Maybe) => match res {
605 Res::Def(DefKind::Trait, _) => true,
606 Res::Def(DefKind::TraitAlias, _) => true,
609 PathSource::Expr(..) => match res {
610 Res::Def(DefKind::Ctor(_, CtorKind::Const), _)
611 | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _)
612 | Res::Def(DefKind::Const, _)
613 | Res::Def(DefKind::Static, _)
615 | Res::Def(DefKind::Fn, _)
616 | Res::Def(DefKind::Method, _)
617 | Res::Def(DefKind::AssocConst, _)
619 | Res::Def(DefKind::ConstParam, _) => true,
622 PathSource::Pat => match res {
623 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
624 Res::Def(DefKind::Const, _) | Res::Def(DefKind::AssocConst, _) |
625 Res::SelfCtor(..) => true,
628 PathSource::TupleStruct => match res {
629 Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..) => true,
632 PathSource::Struct => match res {
633 Res::Def(DefKind::Struct, _)
634 | Res::Def(DefKind::Union, _)
635 | Res::Def(DefKind::Variant, _)
636 | Res::Def(DefKind::TyAlias, _)
637 | Res::Def(DefKind::AssocTy, _)
638 | Res::SelfTy(..) => true,
641 PathSource::TraitItem(ns) => match res {
642 Res::Def(DefKind::AssocConst, _)
643 | Res::Def(DefKind::Method, _) if ns == ValueNS => true,
644 Res::Def(DefKind::AssocTy, _) if ns == TypeNS => true,
647 PathSource::Visibility => match res {
648 Res::Def(DefKind::Mod, _) => true,
654 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
655 __diagnostic_used!(E0404);
656 __diagnostic_used!(E0405);
657 __diagnostic_used!(E0412);
658 __diagnostic_used!(E0422);
659 __diagnostic_used!(E0423);
660 __diagnostic_used!(E0425);
661 __diagnostic_used!(E0531);
662 __diagnostic_used!(E0532);
663 __diagnostic_used!(E0573);
664 __diagnostic_used!(E0574);
665 __diagnostic_used!(E0575);
666 __diagnostic_used!(E0576);
667 __diagnostic_used!(E0577);
668 __diagnostic_used!(E0578);
669 match (self, has_unexpected_resolution) {
670 (PathSource::Trait(_), true) => "E0404",
671 (PathSource::Trait(_), false) => "E0405",
672 (PathSource::Type, true) => "E0573",
673 (PathSource::Type, false) => "E0412",
674 (PathSource::Struct, true) => "E0574",
675 (PathSource::Struct, false) => "E0422",
676 (PathSource::Expr(..), true) => "E0423",
677 (PathSource::Expr(..), false) => "E0425",
678 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
679 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
680 (PathSource::TraitItem(..), true) => "E0575",
681 (PathSource::TraitItem(..), false) => "E0576",
682 (PathSource::Visibility, true) => "E0577",
683 (PathSource::Visibility, false) => "E0578",
688 // A minimal representation of a path segment. We use this in resolve because
689 // we synthesize 'path segments' which don't have the rest of an AST or HIR
691 #[derive(Clone, Copy, Debug)]
698 fn from_path(path: &Path) -> Vec<Segment> {
699 path.segments.iter().map(|s| s.into()).collect()
702 fn from_ident(ident: Ident) -> Segment {
709 fn names_to_string(segments: &[Segment]) -> String {
710 names_to_string(&segments.iter()
711 .map(|seg| seg.ident)
712 .collect::<Vec<_>>())
716 impl<'a> From<&'a ast::PathSegment> for Segment {
717 fn from(seg: &'a ast::PathSegment) -> Segment {
725 struct UsePlacementFinder {
726 target_module: NodeId,
731 impl UsePlacementFinder {
732 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
733 let mut finder = UsePlacementFinder {
738 visit::walk_crate(&mut finder, krate);
739 (finder.span, finder.found_use)
743 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
746 module: &'tcx ast::Mod,
748 _: &[ast::Attribute],
751 if self.span.is_some() {
754 if node_id != self.target_module {
755 visit::walk_mod(self, module);
758 // find a use statement
759 for item in &module.items {
761 ItemKind::Use(..) => {
762 // don't suggest placing a use before the prelude
763 // import or other generated ones
764 if item.span.ctxt().outer_expn_info().is_none() {
765 self.span = Some(item.span.shrink_to_lo());
766 self.found_use = true;
770 // don't place use before extern crate
771 ItemKind::ExternCrate(_) => {}
772 // but place them before the first other item
773 _ => if self.span.map_or(true, |span| item.span < span ) {
774 if item.span.ctxt().outer_expn_info().is_none() {
775 // don't insert between attributes and an item
776 if item.attrs.is_empty() {
777 self.span = Some(item.span.shrink_to_lo());
779 // find the first attribute on the item
780 for attr in &item.attrs {
781 if self.span.map_or(true, |span| attr.span < span) {
782 self.span = Some(attr.span.shrink_to_lo());
793 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
794 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
795 fn visit_item(&mut self, item: &'tcx Item) {
796 self.resolve_item(item);
798 fn visit_arm(&mut self, arm: &'tcx Arm) {
799 self.resolve_arm(arm);
801 fn visit_block(&mut self, block: &'tcx Block) {
802 self.resolve_block(block);
804 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
805 debug!("visit_anon_const {:?}", constant);
806 self.with_constant_rib(|this| {
807 visit::walk_anon_const(this, constant);
810 fn visit_expr(&mut self, expr: &'tcx Expr) {
811 self.resolve_expr(expr, None);
813 fn visit_local(&mut self, local: &'tcx Local) {
814 self.resolve_local(local);
816 fn visit_ty(&mut self, ty: &'tcx Ty) {
818 TyKind::Path(ref qself, ref path) => {
819 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
821 TyKind::ImplicitSelf => {
822 let self_ty = Ident::with_empty_ctxt(kw::SelfUpper);
823 let res = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
824 .map_or(Res::Err, |d| d.res());
825 self.record_partial_res(ty.id, PartialRes::new(res));
829 visit::walk_ty(self, ty);
831 fn visit_poly_trait_ref(&mut self,
832 tref: &'tcx ast::PolyTraitRef,
833 m: &'tcx ast::TraitBoundModifier) {
834 self.smart_resolve_path(tref.trait_ref.ref_id, None,
835 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
836 visit::walk_poly_trait_ref(self, tref, m);
838 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
839 let generic_params = match foreign_item.node {
840 ForeignItemKind::Fn(_, ref generics) => {
841 HasGenericParams(generics, ItemRibKind)
843 ForeignItemKind::Static(..) => NoGenericParams,
844 ForeignItemKind::Ty => NoGenericParams,
845 ForeignItemKind::Macro(..) => NoGenericParams,
847 self.with_generic_param_rib(generic_params, |this| {
848 visit::walk_foreign_item(this, foreign_item);
851 fn visit_fn(&mut self,
852 function_kind: FnKind<'tcx>,
853 declaration: &'tcx FnDecl,
857 debug!("(resolving function) entering function");
858 let rib_kind = match function_kind {
859 FnKind::ItemFn(..) => FnItemRibKind,
860 FnKind::Method(..) => AssocItemRibKind,
861 FnKind::Closure(_) => NormalRibKind,
864 // Create a value rib for the function.
865 self.ribs[ValueNS].push(Rib::new(rib_kind));
867 // Create a label rib for the function.
868 self.label_ribs.push(Rib::new(rib_kind));
870 // Add each argument to the rib.
871 let mut bindings_list = FxHashMap::default();
872 for argument in &declaration.inputs {
873 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
875 self.visit_ty(&argument.ty);
877 debug!("(resolving function) recorded argument");
879 visit::walk_fn_ret_ty(self, &declaration.output);
881 // Resolve the function body, potentially inside the body of an async closure
882 match function_kind {
883 FnKind::ItemFn(.., body) |
884 FnKind::Method(.., body) => {
885 self.visit_block(body);
887 FnKind::Closure(body) => {
888 self.visit_expr(body);
892 debug!("(resolving function) leaving function");
894 self.label_ribs.pop();
895 self.ribs[ValueNS].pop();
898 fn visit_generics(&mut self, generics: &'tcx Generics) {
899 // For type parameter defaults, we have to ban access
900 // to following type parameters, as the InternalSubsts can only
901 // provide previous type parameters as they're built. We
902 // put all the parameters on the ban list and then remove
903 // them one by one as they are processed and become available.
904 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
905 let mut found_default = false;
906 default_ban_rib.bindings.extend(generics.params.iter()
907 .filter_map(|param| match param.kind {
908 GenericParamKind::Const { .. } |
909 GenericParamKind::Lifetime { .. } => None,
910 GenericParamKind::Type { ref default, .. } => {
911 found_default |= default.is_some();
913 Some((Ident::with_empty_ctxt(param.ident.name), Res::Err))
920 // We also ban access to type parameters for use as the types of const parameters.
921 let mut const_ty_param_ban_rib = Rib::new(TyParamAsConstParamTy);
922 const_ty_param_ban_rib.bindings.extend(generics.params.iter()
924 if let GenericParamKind::Type { .. } = param.kind {
930 .map(|param| (Ident::with_empty_ctxt(param.ident.name), Res::Err)));
932 for param in &generics.params {
934 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
935 GenericParamKind::Type { ref default, .. } => {
936 for bound in ¶m.bounds {
937 self.visit_param_bound(bound);
940 if let Some(ref ty) = default {
941 self.ribs[TypeNS].push(default_ban_rib);
943 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
946 // Allow all following defaults to refer to this type parameter.
947 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
949 GenericParamKind::Const { ref ty } => {
950 self.ribs[TypeNS].push(const_ty_param_ban_rib);
952 for bound in ¶m.bounds {
953 self.visit_param_bound(bound);
958 const_ty_param_ban_rib = self.ribs[TypeNS].pop().unwrap();
962 for p in &generics.where_clause.predicates {
963 self.visit_where_predicate(p);
968 #[derive(Copy, Clone)]
969 enum GenericParameters<'a, 'b> {
971 HasGenericParams(// Type parameters.
974 // The kind of the rib used for type parameters.
978 /// The rib kind restricts certain accesses,
979 /// e.g. to a `Res::Local` of an outer item.
980 #[derive(Copy, Clone, Debug)]
982 /// No restriction needs to be applied.
985 /// We passed through an impl or trait and are now in one of its
986 /// methods or associated types. Allow references to ty params that impl or trait
987 /// binds. Disallow any other upvars (including other ty params that are
991 /// We passed through a function definition. Disallow upvars.
992 /// Permit only those const parameters that are specified in the function's generics.
995 /// We passed through an item scope. Disallow upvars.
998 /// We're in a constant item. Can't refer to dynamic stuff.
1001 /// We passed through a module.
1002 ModuleRibKind(Module<'a>),
1004 /// We passed through a `macro_rules!` statement
1005 MacroDefinition(DefId),
1007 /// All bindings in this rib are type parameters that can't be used
1008 /// from the default of a type parameter because they're not declared
1009 /// before said type parameter. Also see the `visit_generics` override.
1010 ForwardTyParamBanRibKind,
1012 /// We forbid the use of type parameters as the types of const parameters.
1013 TyParamAsConstParamTy,
1016 /// A single local scope.
1018 /// A rib represents a scope names can live in. Note that these appear in many places, not just
1019 /// around braces. At any place where the list of accessible names (of the given namespace)
1020 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
1021 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
1024 /// Different [rib kinds](enum.RibKind) are transparent for different names.
1026 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
1027 /// resolving, the name is looked up from inside out.
1029 struct Rib<'a, R = Res> {
1030 bindings: FxHashMap<Ident, R>,
1034 impl<'a, R> Rib<'a, R> {
1035 fn new(kind: RibKind<'a>) -> Rib<'a, R> {
1037 bindings: Default::default(),
1043 /// An intermediate resolution result.
1045 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
1046 /// items are visible in their whole block, while `Res`es only from the place they are defined
1048 enum LexicalScopeBinding<'a> {
1049 Item(&'a NameBinding<'a>),
1053 impl<'a> LexicalScopeBinding<'a> {
1054 fn item(self) -> Option<&'a NameBinding<'a>> {
1056 LexicalScopeBinding::Item(binding) => Some(binding),
1061 fn res(self) -> Res {
1063 LexicalScopeBinding::Item(binding) => binding.res(),
1064 LexicalScopeBinding::Res(res) => res,
1069 #[derive(Copy, Clone, Debug)]
1070 enum ModuleOrUniformRoot<'a> {
1074 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1075 CrateRootAndExternPrelude,
1077 /// Virtual module that denotes resolution in extern prelude.
1078 /// Used for paths starting with `::` on 2018 edition.
1081 /// Virtual module that denotes resolution in current scope.
1082 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1083 /// are always split into two parts, the first of which should be some kind of module.
1087 impl ModuleOrUniformRoot<'_> {
1088 fn same_def(lhs: Self, rhs: Self) -> bool {
1090 (ModuleOrUniformRoot::Module(lhs),
1091 ModuleOrUniformRoot::Module(rhs)) => lhs.def_id() == rhs.def_id(),
1092 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1093 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1094 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1095 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1101 #[derive(Clone, Debug)]
1102 enum PathResult<'a> {
1103 Module(ModuleOrUniformRoot<'a>),
1104 NonModule(PartialRes),
1109 suggestion: Option<Suggestion>,
1110 is_error_from_last_segment: bool,
1115 /// An anonymous module; e.g., just a block.
1119 /// fn f() {} // (1)
1120 /// { // This is an anonymous module
1121 /// f(); // This resolves to (2) as we are inside the block.
1122 /// fn f() {} // (2)
1124 /// f(); // Resolves to (1)
1128 /// Any module with a name.
1132 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1133 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1135 Def(DefKind, DefId, Name),
1139 /// Get name of the module.
1140 pub fn name(&self) -> Option<Name> {
1142 ModuleKind::Block(..) => None,
1143 ModuleKind::Def(.., name) => Some(*name),
1148 /// One node in the tree of modules.
1149 pub struct ModuleData<'a> {
1150 parent: Option<Module<'a>>,
1153 // The def id of the closest normal module (`mod`) ancestor (including this module).
1154 normal_ancestor_id: DefId,
1156 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1157 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1158 Option<&'a NameBinding<'a>>)>>,
1159 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1161 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1163 // Macro invocations that can expand into items in this module.
1164 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1166 no_implicit_prelude: bool,
1168 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1169 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1171 // Used to memoize the traits in this module for faster searches through all traits in scope.
1172 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1174 // Whether this module is populated. If not populated, any attempt to
1175 // access the children must be preceded with a
1176 // `populate_module_if_necessary` call.
1177 populated: Cell<bool>,
1179 /// Span of the module itself. Used for error reporting.
1185 type Module<'a> = &'a ModuleData<'a>;
1187 impl<'a> ModuleData<'a> {
1188 fn new(parent: Option<Module<'a>>,
1190 normal_ancestor_id: DefId,
1192 span: Span) -> Self {
1197 resolutions: Default::default(),
1198 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1199 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1200 builtin_attrs: RefCell::new(Vec::new()),
1201 unresolved_invocations: Default::default(),
1202 no_implicit_prelude: false,
1203 glob_importers: RefCell::new(Vec::new()),
1204 globs: RefCell::new(Vec::new()),
1205 traits: RefCell::new(None),
1206 populated: Cell::new(normal_ancestor_id.is_local()),
1212 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1213 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1214 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1218 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1219 let resolutions = self.resolutions.borrow();
1220 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1221 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1222 for &(&(ident, ns), &resolution) in resolutions.iter() {
1223 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1227 fn res(&self) -> Option<Res> {
1229 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
1234 fn def_kind(&self) -> Option<DefKind> {
1236 ModuleKind::Def(kind, ..) => Some(kind),
1241 fn def_id(&self) -> Option<DefId> {
1243 ModuleKind::Def(_, def_id, _) => Some(def_id),
1248 // `self` resolves to the first module ancestor that `is_normal`.
1249 fn is_normal(&self) -> bool {
1251 ModuleKind::Def(DefKind::Mod, _, _) => true,
1256 fn is_trait(&self) -> bool {
1258 ModuleKind::Def(DefKind::Trait, _, _) => true,
1263 fn nearest_item_scope(&'a self) -> Module<'a> {
1264 if self.is_trait() { self.parent.unwrap() } else { self }
1267 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1268 while !ptr::eq(self, other) {
1269 if let Some(parent) = other.parent {
1279 impl<'a> fmt::Debug for ModuleData<'a> {
1280 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1281 write!(f, "{:?}", self.res())
1285 /// Records a possibly-private value, type, or module definition.
1286 #[derive(Clone, Debug)]
1287 pub struct NameBinding<'a> {
1288 kind: NameBindingKind<'a>,
1289 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1292 vis: ty::Visibility,
1295 pub trait ToNameBinding<'a> {
1296 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1299 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1300 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1305 #[derive(Clone, Debug)]
1306 enum NameBindingKind<'a> {
1307 Res(Res, /* is_macro_export */ bool),
1310 binding: &'a NameBinding<'a>,
1311 directive: &'a ImportDirective<'a>,
1316 impl<'a> NameBindingKind<'a> {
1317 /// Is this a name binding of a import?
1318 fn is_import(&self) -> bool {
1320 NameBindingKind::Import { .. } => true,
1326 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1328 struct UseError<'a> {
1329 err: DiagnosticBuilder<'a>,
1330 /// Attach `use` statements for these candidates.
1331 candidates: Vec<ImportSuggestion>,
1332 /// The `NodeId` of the module to place the use-statements in.
1334 /// Whether the diagnostic should state that it's "better".
1338 #[derive(Clone, Copy, PartialEq, Debug)]
1339 enum AmbiguityKind {
1343 LegacyHelperVsPrelude,
1348 MoreExpandedVsOuter,
1351 impl AmbiguityKind {
1352 fn descr(self) -> &'static str {
1354 AmbiguityKind::Import =>
1355 "name vs any other name during import resolution",
1356 AmbiguityKind::BuiltinAttr =>
1357 "built-in attribute vs any other name",
1358 AmbiguityKind::DeriveHelper =>
1359 "derive helper attribute vs any other name",
1360 AmbiguityKind::LegacyHelperVsPrelude =>
1361 "legacy plugin helper attribute vs name from prelude",
1362 AmbiguityKind::LegacyVsModern =>
1363 "`macro_rules` vs non-`macro_rules` from other module",
1364 AmbiguityKind::GlobVsOuter =>
1365 "glob import vs any other name from outer scope during import/macro resolution",
1366 AmbiguityKind::GlobVsGlob =>
1367 "glob import vs glob import in the same module",
1368 AmbiguityKind::GlobVsExpanded =>
1369 "glob import vs macro-expanded name in the same \
1370 module during import/macro resolution",
1371 AmbiguityKind::MoreExpandedVsOuter =>
1372 "macro-expanded name vs less macro-expanded name \
1373 from outer scope during import/macro resolution",
1378 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1379 #[derive(Clone, Copy, PartialEq)]
1380 enum AmbiguityErrorMisc {
1387 struct AmbiguityError<'a> {
1388 kind: AmbiguityKind,
1390 b1: &'a NameBinding<'a>,
1391 b2: &'a NameBinding<'a>,
1392 misc1: AmbiguityErrorMisc,
1393 misc2: AmbiguityErrorMisc,
1396 impl<'a> NameBinding<'a> {
1397 fn module(&self) -> Option<Module<'a>> {
1399 NameBindingKind::Module(module) => Some(module),
1400 NameBindingKind::Import { binding, .. } => binding.module(),
1405 fn res(&self) -> Res {
1407 NameBindingKind::Res(res, _) => res,
1408 NameBindingKind::Module(module) => module.res().unwrap(),
1409 NameBindingKind::Import { binding, .. } => binding.res(),
1413 fn is_ambiguity(&self) -> bool {
1414 self.ambiguity.is_some() || match self.kind {
1415 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1420 // We sometimes need to treat variants as `pub` for backwards compatibility.
1421 fn pseudo_vis(&self) -> ty::Visibility {
1422 if self.is_variant() && self.res().def_id().is_local() {
1423 ty::Visibility::Public
1429 fn is_variant(&self) -> bool {
1431 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _) |
1432 NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
1437 fn is_extern_crate(&self) -> bool {
1439 NameBindingKind::Import {
1440 directive: &ImportDirective {
1441 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1444 NameBindingKind::Module(
1445 &ModuleData { kind: ModuleKind::Def(DefKind::Mod, def_id, _), .. }
1446 ) => def_id.index == CRATE_DEF_INDEX,
1451 fn is_import(&self) -> bool {
1453 NameBindingKind::Import { .. } => true,
1458 fn is_glob_import(&self) -> bool {
1460 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1465 fn is_importable(&self) -> bool {
1467 Res::Def(DefKind::AssocConst, _)
1468 | Res::Def(DefKind::Method, _)
1469 | Res::Def(DefKind::AssocTy, _) => false,
1474 fn is_macro_def(&self) -> bool {
1476 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
1481 fn macro_kind(&self) -> Option<MacroKind> {
1483 Res::Def(DefKind::Macro(kind), _) => Some(kind),
1484 Res::NonMacroAttr(..) => Some(MacroKind::Attr),
1489 fn descr(&self) -> &'static str {
1490 if self.is_extern_crate() { "extern crate" } else { self.res().descr() }
1493 fn article(&self) -> &'static str {
1494 if self.is_extern_crate() { "an" } else { self.res().article() }
1497 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1498 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1499 // Then this function returns `true` if `self` may emerge from a macro *after* that
1500 // in some later round and screw up our previously found resolution.
1501 // See more detailed explanation in
1502 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1503 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1504 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1505 // Expansions are partially ordered, so "may appear after" is an inversion of
1506 // "certainly appears before or simultaneously" and includes unordered cases.
1507 let self_parent_expansion = self.expansion;
1508 let other_parent_expansion = binding.expansion;
1509 let certainly_before_other_or_simultaneously =
1510 other_parent_expansion.is_descendant_of(self_parent_expansion);
1511 let certainly_before_invoc_or_simultaneously =
1512 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1513 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1517 /// Interns the names of the primitive types.
1519 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1520 /// special handling, since they have no place of origin.
1522 struct PrimitiveTypeTable {
1523 primitive_types: FxHashMap<Name, PrimTy>,
1526 impl PrimitiveTypeTable {
1527 fn new() -> PrimitiveTypeTable {
1528 let mut table = PrimitiveTypeTable::default();
1530 table.intern("bool", Bool);
1531 table.intern("char", Char);
1532 table.intern("f32", Float(FloatTy::F32));
1533 table.intern("f64", Float(FloatTy::F64));
1534 table.intern("isize", Int(IntTy::Isize));
1535 table.intern("i8", Int(IntTy::I8));
1536 table.intern("i16", Int(IntTy::I16));
1537 table.intern("i32", Int(IntTy::I32));
1538 table.intern("i64", Int(IntTy::I64));
1539 table.intern("i128", Int(IntTy::I128));
1540 table.intern("str", Str);
1541 table.intern("usize", Uint(UintTy::Usize));
1542 table.intern("u8", Uint(UintTy::U8));
1543 table.intern("u16", Uint(UintTy::U16));
1544 table.intern("u32", Uint(UintTy::U32));
1545 table.intern("u64", Uint(UintTy::U64));
1546 table.intern("u128", Uint(UintTy::U128));
1550 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1551 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1555 #[derive(Debug, Default, Clone)]
1556 pub struct ExternPreludeEntry<'a> {
1557 extern_crate_item: Option<&'a NameBinding<'a>>,
1558 pub introduced_by_item: bool,
1561 /// The main resolver class.
1563 /// This is the visitor that walks the whole crate.
1564 pub struct Resolver<'a> {
1565 session: &'a Session,
1568 pub definitions: Definitions,
1570 graph_root: Module<'a>,
1572 prelude: Option<Module<'a>>,
1573 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1575 /// N.B., this is used only for better diagnostics, not name resolution itself.
1576 has_self: FxHashSet<DefId>,
1578 /// Names of fields of an item `DefId` accessible with dot syntax.
1579 /// Used for hints during error reporting.
1580 field_names: FxHashMap<DefId, Vec<Name>>,
1582 /// All imports known to succeed or fail.
1583 determined_imports: Vec<&'a ImportDirective<'a>>,
1585 /// All non-determined imports.
1586 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1588 /// The module that represents the current item scope.
1589 current_module: Module<'a>,
1591 /// The current set of local scopes for types and values.
1592 /// FIXME #4948: Reuse ribs to avoid allocation.
1593 ribs: PerNS<Vec<Rib<'a>>>,
1595 /// The current set of local scopes, for labels.
1596 label_ribs: Vec<Rib<'a, NodeId>>,
1598 /// The trait that the current context can refer to.
1599 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1601 /// The current self type if inside an impl (used for better errors).
1602 current_self_type: Option<Ty>,
1604 /// The current self item if inside an ADT (used for better errors).
1605 current_self_item: Option<NodeId>,
1607 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1608 /// We are resolving a last import segment during import validation.
1609 last_import_segment: bool,
1610 /// This binding should be ignored during in-module resolution, so that we don't get
1611 /// "self-confirming" import resolutions during import validation.
1612 blacklisted_binding: Option<&'a NameBinding<'a>>,
1614 /// The idents for the primitive types.
1615 primitive_type_table: PrimitiveTypeTable,
1617 /// Resolutions for nodes that have a single resolution.
1618 partial_res_map: NodeMap<PartialRes>,
1619 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
1620 import_res_map: NodeMap<PerNS<Option<Res>>>,
1621 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
1622 label_res_map: NodeMap<NodeId>,
1624 pub export_map: ExportMap<NodeId>,
1625 pub trait_map: TraitMap,
1627 /// A map from nodes to anonymous modules.
1628 /// Anonymous modules are pseudo-modules that are implicitly created around items
1629 /// contained within blocks.
1631 /// For example, if we have this:
1639 /// There will be an anonymous module created around `g` with the ID of the
1640 /// entry block for `f`.
1641 block_map: NodeMap<Module<'a>>,
1642 module_map: FxHashMap<DefId, Module<'a>>,
1643 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1644 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1646 /// Maps glob imports to the names of items actually imported.
1647 pub glob_map: GlobMap,
1649 used_imports: FxHashSet<(NodeId, Namespace)>,
1650 pub maybe_unused_trait_imports: NodeSet,
1651 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1653 /// A list of labels as of yet unused. Labels will be removed from this map when
1654 /// they are used (in a `break` or `continue` statement)
1655 pub unused_labels: FxHashMap<NodeId, Span>,
1657 /// Privacy errors are delayed until the end in order to deduplicate them.
1658 privacy_errors: Vec<PrivacyError<'a>>,
1659 /// Ambiguity errors are delayed for deduplication.
1660 ambiguity_errors: Vec<AmbiguityError<'a>>,
1661 /// `use` injections are delayed for better placement and deduplication.
1662 use_injections: Vec<UseError<'a>>,
1663 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1664 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1666 arenas: &'a ResolverArenas<'a>,
1667 dummy_binding: &'a NameBinding<'a>,
1669 crate_loader: &'a mut CrateLoader<'a>,
1670 macro_names: FxHashSet<Ident>,
1671 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1672 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1673 pub all_macros: FxHashMap<Name, Res>,
1674 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1675 macro_defs: FxHashMap<Mark, DefId>,
1676 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1678 /// List of crate local macros that we need to warn about as being unused.
1679 /// Right now this only includes macro_rules! macros, and macros 2.0.
1680 unused_macros: FxHashSet<DefId>,
1682 /// Maps the `Mark` of an expansion to its containing module or block.
1683 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1685 /// Avoid duplicated errors for "name already defined".
1686 name_already_seen: FxHashMap<Name, Span>,
1688 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1690 /// Table for mapping struct IDs into struct constructor IDs,
1691 /// it's not used during normal resolution, only for better error reporting.
1692 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
1694 /// Only used for better errors on `fn(): fn()`.
1695 current_type_ascription: Vec<Span>,
1697 injected_crate: Option<Module<'a>>,
1700 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1702 pub struct ResolverArenas<'a> {
1703 modules: arena::TypedArena<ModuleData<'a>>,
1704 local_modules: RefCell<Vec<Module<'a>>>,
1705 name_bindings: arena::TypedArena<NameBinding<'a>>,
1706 import_directives: arena::TypedArena<ImportDirective<'a>>,
1707 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1708 invocation_data: arena::TypedArena<InvocationData<'a>>,
1709 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1712 impl<'a> ResolverArenas<'a> {
1713 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1714 let module = self.modules.alloc(module);
1715 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1716 self.local_modules.borrow_mut().push(module);
1720 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1721 self.local_modules.borrow()
1723 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1724 self.name_bindings.alloc(name_binding)
1726 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1727 -> &'a ImportDirective<'_> {
1728 self.import_directives.alloc(import_directive)
1730 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1731 self.name_resolutions.alloc(Default::default())
1733 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1734 -> &'a InvocationData<'a> {
1735 self.invocation_data.alloc(expansion_data)
1737 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1738 self.legacy_bindings.alloc(binding)
1742 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1743 fn parent(self, id: DefId) -> Option<DefId> {
1745 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1746 _ => self.cstore.def_key(id).parent,
1747 }.map(|index| DefId { index, ..id })
1751 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1752 /// the resolver is no longer needed as all the relevant information is inline.
1753 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1754 fn resolve_hir_path(
1759 self.resolve_hir_path_cb(path, is_value,
1760 |resolver, span, error| resolve_error(resolver, span, error))
1763 fn resolve_str_path(
1766 crate_root: Option<Symbol>,
1767 components: &[Symbol],
1770 let root = if crate_root.is_some() {
1775 let segments = iter::once(Ident::with_empty_ctxt(root))
1777 crate_root.into_iter()
1778 .chain(components.iter().cloned())
1779 .map(Ident::with_empty_ctxt)
1780 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1782 let path = ast::Path {
1787 self.resolve_hir_path(&path, is_value)
1790 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1791 self.partial_res_map.get(&id).cloned()
1794 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1795 self.import_res_map.get(&id).cloned().unwrap_or_default()
1798 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1799 self.label_res_map.get(&id).cloned()
1802 fn definitions(&mut self) -> &mut Definitions {
1803 &mut self.definitions
1807 impl<'a> Resolver<'a> {
1808 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1809 /// isn't something that can be returned because it can't be made to live that long,
1810 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1811 /// just that an error occurred.
1812 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1813 -> Result<hir::Path, ()> {
1814 let mut errored = false;
1816 let path = if path_str.starts_with("::") {
1819 segments: iter::once(Ident::with_empty_ctxt(kw::PathRoot))
1821 path_str.split("::").skip(1).map(Ident::from_str)
1823 .map(|i| self.new_ast_path_segment(i))
1831 .map(Ident::from_str)
1832 .map(|i| self.new_ast_path_segment(i))
1836 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1837 if errored || path.res == def::Res::Err {
1844 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1845 fn resolve_hir_path_cb<F>(
1851 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1853 let namespace = if is_value { ValueNS } else { TypeNS };
1854 let span = path.span;
1855 let segments = &path.segments;
1856 let path = Segment::from_path(&path);
1857 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1858 let res = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1859 span, CrateLint::No) {
1860 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1861 module.res().unwrap(),
1862 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1863 path_res.base_res(),
1864 PathResult::NonModule(..) => {
1865 error_callback(self, span, ResolutionError::FailedToResolve {
1866 label: String::from("type-relative paths are not supported in this context"),
1871 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1872 PathResult::Failed { span, label, suggestion, .. } => {
1873 error_callback(self, span, ResolutionError::FailedToResolve {
1881 let segments: Vec<_> = segments.iter().map(|seg| {
1882 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1883 hir_seg.res = Some(self.partial_res_map.get(&seg.id).map_or(def::Res::Err, |p| {
1884 p.base_res().map_id(|_| panic!("unexpected node_id"))
1890 res: res.map_id(|_| panic!("unexpected node_id")),
1891 segments: segments.into(),
1895 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1896 let mut seg = ast::PathSegment::from_ident(ident);
1897 seg.id = self.session.next_node_id();
1902 impl<'a> Resolver<'a> {
1903 pub fn new(session: &'a Session,
1907 crate_loader: &'a mut CrateLoader<'a>,
1908 arenas: &'a ResolverArenas<'a>)
1910 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1911 let root_module_kind = ModuleKind::Def(
1916 let graph_root = arenas.alloc_module(ModuleData {
1917 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1918 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1920 let mut module_map = FxHashMap::default();
1921 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1923 let mut definitions = Definitions::default();
1924 DefCollector::new(&mut definitions, Mark::root())
1925 .collect_root(crate_name, session.local_crate_disambiguator());
1927 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1928 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1931 if !attr::contains_name(&krate.attrs, sym::no_core) {
1932 extern_prelude.insert(Ident::with_empty_ctxt(sym::core), Default::default());
1933 if !attr::contains_name(&krate.attrs, sym::no_std) {
1934 extern_prelude.insert(Ident::with_empty_ctxt(sym::std), Default::default());
1935 if session.rust_2018() {
1936 extern_prelude.insert(Ident::with_empty_ctxt(sym::meta), Default::default());
1941 let mut invocations = FxHashMap::default();
1942 invocations.insert(Mark::root(),
1943 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1945 let mut macro_defs = FxHashMap::default();
1946 macro_defs.insert(Mark::root(), root_def_id);
1955 // The outermost module has def ID 0; this is not reflected in the
1961 has_self: FxHashSet::default(),
1962 field_names: FxHashMap::default(),
1964 determined_imports: Vec::new(),
1965 indeterminate_imports: Vec::new(),
1967 current_module: graph_root,
1969 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1970 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1971 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1973 label_ribs: Vec::new(),
1975 current_trait_ref: None,
1976 current_self_type: None,
1977 current_self_item: None,
1978 last_import_segment: false,
1979 blacklisted_binding: None,
1981 primitive_type_table: PrimitiveTypeTable::new(),
1983 partial_res_map: Default::default(),
1984 import_res_map: Default::default(),
1985 label_res_map: Default::default(),
1986 export_map: FxHashMap::default(),
1987 trait_map: Default::default(),
1989 block_map: Default::default(),
1990 extern_module_map: FxHashMap::default(),
1991 binding_parent_modules: FxHashMap::default(),
1993 glob_map: Default::default(),
1995 used_imports: FxHashSet::default(),
1996 maybe_unused_trait_imports: Default::default(),
1997 maybe_unused_extern_crates: Vec::new(),
1999 unused_labels: FxHashMap::default(),
2001 privacy_errors: Vec::new(),
2002 ambiguity_errors: Vec::new(),
2003 use_injections: Vec::new(),
2004 macro_expanded_macro_export_errors: BTreeSet::new(),
2007 dummy_binding: arenas.alloc_name_binding(NameBinding {
2008 kind: NameBindingKind::Res(Res::Err, false),
2010 expansion: Mark::root(),
2012 vis: ty::Visibility::Public,
2016 macro_names: FxHashSet::default(),
2017 builtin_macros: FxHashMap::default(),
2018 macro_use_prelude: FxHashMap::default(),
2019 all_macros: FxHashMap::default(),
2020 macro_map: FxHashMap::default(),
2023 local_macro_def_scopes: FxHashMap::default(),
2024 name_already_seen: FxHashMap::default(),
2025 potentially_unused_imports: Vec::new(),
2026 struct_constructors: Default::default(),
2027 unused_macros: FxHashSet::default(),
2028 current_type_ascription: Vec::new(),
2029 injected_crate: None,
2033 pub fn arenas() -> ResolverArenas<'a> {
2037 /// Runs the function on each namespace.
2038 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
2044 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
2046 match self.macro_defs.get(&ctxt.outer()) {
2047 Some(&def_id) => return def_id,
2048 None => ctxt.remove_mark(),
2053 /// Entry point to crate resolution.
2054 pub fn resolve_crate(&mut self, krate: &Crate) {
2055 ImportResolver { resolver: self }.finalize_imports();
2056 self.current_module = self.graph_root;
2057 self.finalize_current_module_macro_resolutions();
2059 visit::walk_crate(self, krate);
2061 check_unused::check_crate(self, krate);
2062 self.report_errors(krate);
2063 self.crate_loader.postprocess(krate);
2070 normal_ancestor_id: DefId,
2074 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
2075 self.arenas.alloc_module(module)
2078 fn record_use(&mut self, ident: Ident, ns: Namespace,
2079 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
2080 if let Some((b2, kind)) = used_binding.ambiguity {
2081 self.ambiguity_errors.push(AmbiguityError {
2082 kind, ident, b1: used_binding, b2,
2083 misc1: AmbiguityErrorMisc::None,
2084 misc2: AmbiguityErrorMisc::None,
2087 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
2088 // Avoid marking `extern crate` items that refer to a name from extern prelude,
2089 // but not introduce it, as used if they are accessed from lexical scope.
2090 if is_lexical_scope {
2091 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
2092 if let Some(crate_item) = entry.extern_crate_item {
2093 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2100 directive.used.set(true);
2101 self.used_imports.insert((directive.id, ns));
2102 self.add_to_glob_map(&directive, ident);
2103 self.record_use(ident, ns, binding, false);
2108 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2109 if directive.is_glob() {
2110 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2114 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2115 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2116 /// `ident` in the first scope that defines it (or None if no scopes define it).
2118 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2119 /// the items are defined in the block. For example,
2122 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2125 /// g(); // This resolves to the local variable `g` since it shadows the item.
2129 /// Invariant: This must only be called during main resolution, not during
2130 /// import resolution.
2131 fn resolve_ident_in_lexical_scope(&mut self,
2134 record_used_id: Option<NodeId>,
2136 -> Option<LexicalScopeBinding<'a>> {
2137 assert!(ns == TypeNS || ns == ValueNS);
2138 if ident.name == kw::Invalid {
2139 return Some(LexicalScopeBinding::Res(Res::Err));
2141 ident.span = if ident.name == kw::SelfUpper {
2142 // FIXME(jseyfried) improve `Self` hygiene
2143 ident.span.with_ctxt(SyntaxContext::empty())
2144 } else if ns == TypeNS {
2147 ident.span.modern_and_legacy()
2150 // Walk backwards up the ribs in scope.
2151 let record_used = record_used_id.is_some();
2152 let mut module = self.graph_root;
2153 for i in (0 .. self.ribs[ns].len()).rev() {
2154 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2155 if let Some(res) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2156 // The ident resolves to a type parameter or local variable.
2157 return Some(LexicalScopeBinding::Res(
2158 self.validate_res_from_ribs(ns, i, res, record_used, path_span),
2162 module = match self.ribs[ns][i].kind {
2163 ModuleRibKind(module) => module,
2164 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2165 // If an invocation of this macro created `ident`, give up on `ident`
2166 // and switch to `ident`'s source from the macro definition.
2167 ident.span.remove_mark();
2173 let item = self.resolve_ident_in_module_unadjusted(
2174 ModuleOrUniformRoot::Module(module),
2180 if let Ok(binding) = item {
2181 // The ident resolves to an item.
2182 return Some(LexicalScopeBinding::Item(binding));
2186 ModuleKind::Block(..) => {}, // We can see through blocks
2191 ident.span = ident.span.modern();
2192 let mut poisoned = None;
2194 let opt_module = if let Some(node_id) = record_used_id {
2195 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2196 node_id, &mut poisoned)
2198 self.hygienic_lexical_parent(module, &mut ident.span)
2200 module = unwrap_or!(opt_module, break);
2201 let orig_current_module = self.current_module;
2202 self.current_module = module; // Lexical resolutions can never be a privacy error.
2203 let result = self.resolve_ident_in_module_unadjusted(
2204 ModuleOrUniformRoot::Module(module),
2210 self.current_module = orig_current_module;
2214 if let Some(node_id) = poisoned {
2215 self.session.buffer_lint_with_diagnostic(
2216 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2217 node_id, ident.span,
2218 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2219 lint::builtin::BuiltinLintDiagnostics::
2220 ProcMacroDeriveResolutionFallback(ident.span),
2223 return Some(LexicalScopeBinding::Item(binding))
2225 Err(Determined) => continue,
2226 Err(Undetermined) =>
2227 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2231 if !module.no_implicit_prelude {
2233 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2234 return Some(LexicalScopeBinding::Item(binding));
2237 if ns == TypeNS && is_known_tool(ident.name) {
2238 let binding = (Res::ToolMod, ty::Visibility::Public,
2239 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2240 return Some(LexicalScopeBinding::Item(binding));
2242 if let Some(prelude) = self.prelude {
2243 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2244 ModuleOrUniformRoot::Module(prelude),
2250 return Some(LexicalScopeBinding::Item(binding));
2258 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2259 -> Option<Module<'a>> {
2260 if !module.expansion.outer_is_descendant_of(span.ctxt()) {
2261 return Some(self.macro_def_scope(span.remove_mark()));
2264 if let ModuleKind::Block(..) = module.kind {
2265 return Some(module.parent.unwrap());
2271 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2272 span: &mut Span, node_id: NodeId,
2273 poisoned: &mut Option<NodeId>)
2274 -> Option<Module<'a>> {
2275 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2279 // We need to support the next case under a deprecation warning
2282 // ---- begin: this comes from a proc macro derive
2283 // mod implementation_details {
2284 // // Note that `MyStruct` is not in scope here.
2285 // impl SomeTrait for MyStruct { ... }
2289 // So we have to fall back to the module's parent during lexical resolution in this case.
2290 if let Some(parent) = module.parent {
2291 // Inner module is inside the macro, parent module is outside of the macro.
2292 if module.expansion != parent.expansion &&
2293 module.expansion.is_descendant_of(parent.expansion) {
2294 // The macro is a proc macro derive
2295 if module.expansion.looks_like_proc_macro_derive() {
2296 if parent.expansion.outer_is_descendant_of(span.ctxt()) {
2297 *poisoned = Some(node_id);
2298 return module.parent;
2307 fn resolve_ident_in_module(
2309 module: ModuleOrUniformRoot<'a>,
2312 parent_scope: Option<&ParentScope<'a>>,
2315 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2316 self.resolve_ident_in_module_ext(
2317 module, ident, ns, parent_scope, record_used, path_span
2318 ).map_err(|(determinacy, _)| determinacy)
2321 fn resolve_ident_in_module_ext(
2323 module: ModuleOrUniformRoot<'a>,
2326 parent_scope: Option<&ParentScope<'a>>,
2329 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2330 let orig_current_module = self.current_module;
2332 ModuleOrUniformRoot::Module(module) => {
2333 if let Some(def) = ident.span.modernize_and_adjust(module.expansion) {
2334 self.current_module = self.macro_def_scope(def);
2337 ModuleOrUniformRoot::ExternPrelude => {
2338 ident.span.modernize_and_adjust(Mark::root());
2340 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2341 ModuleOrUniformRoot::CurrentScope => {
2345 let result = self.resolve_ident_in_module_unadjusted_ext(
2346 module, ident, ns, parent_scope, false, record_used, path_span,
2348 self.current_module = orig_current_module;
2352 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2353 let mut ctxt = ident.span.ctxt();
2354 let mark = if ident.name == kw::DollarCrate {
2355 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2356 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2357 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2358 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2359 // definitions actually produced by `macro` and `macro` definitions produced by
2360 // `macro_rules!`, but at least such configurations are not stable yet.
2361 ctxt = ctxt.modern_and_legacy();
2362 let mut iter = ctxt.marks().into_iter().rev().peekable();
2363 let mut result = None;
2364 // Find the last modern mark from the end if it exists.
2365 while let Some(&(mark, transparency)) = iter.peek() {
2366 if transparency == Transparency::Opaque {
2367 result = Some(mark);
2373 // Then find the last legacy mark from the end if it exists.
2374 for (mark, transparency) in iter {
2375 if transparency == Transparency::SemiTransparent {
2376 result = Some(mark);
2383 ctxt = ctxt.modern();
2384 ctxt.adjust(Mark::root())
2386 let module = match mark {
2387 Some(def) => self.macro_def_scope(def),
2388 None => return self.graph_root,
2390 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2393 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2394 let mut module = self.get_module(module.normal_ancestor_id);
2395 while module.span.ctxt().modern() != *ctxt {
2396 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2397 module = self.get_module(parent.normal_ancestor_id);
2404 // We maintain a list of value ribs and type ribs.
2406 // Simultaneously, we keep track of the current position in the module
2407 // graph in the `current_module` pointer. When we go to resolve a name in
2408 // the value or type namespaces, we first look through all the ribs and
2409 // then query the module graph. When we resolve a name in the module
2410 // namespace, we can skip all the ribs (since nested modules are not
2411 // allowed within blocks in Rust) and jump straight to the current module
2414 // Named implementations are handled separately. When we find a method
2415 // call, we consult the module node to find all of the implementations in
2416 // scope. This information is lazily cached in the module node. We then
2417 // generate a fake "implementation scope" containing all the
2418 // implementations thus found, for compatibility with old resolve pass.
2420 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2421 where F: FnOnce(&mut Resolver<'_>) -> T
2423 let id = self.definitions.local_def_id(id);
2424 let module = self.module_map.get(&id).cloned(); // clones a reference
2425 if let Some(module) = module {
2426 // Move down in the graph.
2427 let orig_module = replace(&mut self.current_module, module);
2428 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2429 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2431 self.finalize_current_module_macro_resolutions();
2434 self.current_module = orig_module;
2435 self.ribs[ValueNS].pop();
2436 self.ribs[TypeNS].pop();
2443 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2444 /// is returned by the given predicate function
2446 /// Stops after meeting a closure.
2447 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2448 where P: Fn(&Rib<'_, NodeId>, Ident) -> Option<R>
2450 for rib in self.label_ribs.iter().rev() {
2453 // If an invocation of this macro created `ident`, give up on `ident`
2454 // and switch to `ident`'s source from the macro definition.
2455 MacroDefinition(def) => {
2456 if def == self.macro_def(ident.span.ctxt()) {
2457 ident.span.remove_mark();
2461 // Do not resolve labels across function boundary
2465 let r = pred(rib, ident);
2473 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2474 debug!("resolve_adt");
2475 self.with_current_self_item(item, |this| {
2476 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2477 let item_def_id = this.definitions.local_def_id(item.id);
2478 this.with_self_rib(Res::SelfTy(None, Some(item_def_id)), |this| {
2479 visit::walk_item(this, item);
2485 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2486 let segments = &use_tree.prefix.segments;
2487 if !segments.is_empty() {
2488 let ident = segments[0].ident;
2489 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2493 let nss = match use_tree.kind {
2494 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2497 let report_error = |this: &Self, ns| {
2498 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2499 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2503 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2504 Some(LexicalScopeBinding::Res(..)) => {
2505 report_error(self, ns);
2507 Some(LexicalScopeBinding::Item(binding)) => {
2508 let orig_blacklisted_binding =
2509 mem::replace(&mut self.blacklisted_binding, Some(binding));
2510 if let Some(LexicalScopeBinding::Res(..)) =
2511 self.resolve_ident_in_lexical_scope(ident, ns, None,
2512 use_tree.prefix.span) {
2513 report_error(self, ns);
2515 self.blacklisted_binding = orig_blacklisted_binding;
2520 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2521 for (use_tree, _) in use_trees {
2522 self.future_proof_import(use_tree);
2527 fn resolve_item(&mut self, item: &Item) {
2528 let name = item.ident.name;
2529 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2532 ItemKind::Ty(_, ref generics) |
2533 ItemKind::Fn(_, _, ref generics, _) |
2534 ItemKind::Existential(_, ref generics) => {
2535 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2536 |this| visit::walk_item(this, item));
2539 ItemKind::Enum(_, ref generics) |
2540 ItemKind::Struct(_, ref generics) |
2541 ItemKind::Union(_, ref generics) => {
2542 self.resolve_adt(item, generics);
2545 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2546 self.resolve_implementation(generics,
2552 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2553 // Create a new rib for the trait-wide type parameters.
2554 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2555 let local_def_id = this.definitions.local_def_id(item.id);
2556 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2557 this.visit_generics(generics);
2558 walk_list!(this, visit_param_bound, bounds);
2560 for trait_item in trait_items {
2561 let generic_params = HasGenericParams(&trait_item.generics,
2563 this.with_generic_param_rib(generic_params, |this| {
2564 match trait_item.node {
2565 TraitItemKind::Const(ref ty, ref default) => {
2568 // Only impose the restrictions of
2569 // ConstRibKind for an actual constant
2570 // expression in a provided default.
2571 if let Some(ref expr) = *default{
2572 this.with_constant_rib(|this| {
2573 this.visit_expr(expr);
2577 TraitItemKind::Method(_, _) => {
2578 visit::walk_trait_item(this, trait_item)
2580 TraitItemKind::Type(..) => {
2581 visit::walk_trait_item(this, trait_item)
2583 TraitItemKind::Macro(_) => {
2584 panic!("unexpanded macro in resolve!")
2593 ItemKind::TraitAlias(ref generics, ref bounds) => {
2594 // Create a new rib for the trait-wide type parameters.
2595 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2596 let local_def_id = this.definitions.local_def_id(item.id);
2597 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2598 this.visit_generics(generics);
2599 walk_list!(this, visit_param_bound, bounds);
2604 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2605 self.with_scope(item.id, |this| {
2606 visit::walk_item(this, item);
2610 ItemKind::Static(ref ty, _, ref expr) |
2611 ItemKind::Const(ref ty, ref expr) => {
2612 debug!("resolve_item ItemKind::Const");
2613 self.with_item_rib(|this| {
2615 this.with_constant_rib(|this| {
2616 this.visit_expr(expr);
2621 ItemKind::Use(ref use_tree) => {
2622 self.future_proof_import(use_tree);
2625 ItemKind::ExternCrate(..) |
2626 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2627 // do nothing, these are just around to be encoded
2630 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2634 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2635 where F: FnOnce(&mut Resolver<'_>)
2637 debug!("with_generic_param_rib");
2638 match generic_params {
2639 HasGenericParams(generics, rib_kind) => {
2640 let mut function_type_rib = Rib::new(rib_kind);
2641 let mut function_value_rib = Rib::new(rib_kind);
2642 let mut seen_bindings = FxHashMap::default();
2643 for param in &generics.params {
2645 GenericParamKind::Lifetime { .. } => {}
2646 GenericParamKind::Type { .. } => {
2647 let ident = param.ident.modern();
2648 debug!("with_generic_param_rib: {}", param.id);
2650 if seen_bindings.contains_key(&ident) {
2651 let span = seen_bindings.get(&ident).unwrap();
2652 let err = ResolutionError::NameAlreadyUsedInParameterList(
2656 resolve_error(self, param.ident.span, err);
2658 seen_bindings.entry(ident).or_insert(param.ident.span);
2660 // Plain insert (no renaming).
2663 self.definitions.local_def_id(param.id),
2665 function_type_rib.bindings.insert(ident, res);
2666 self.record_partial_res(param.id, PartialRes::new(res));
2668 GenericParamKind::Const { .. } => {
2669 let ident = param.ident.modern();
2670 debug!("with_generic_param_rib: {}", param.id);
2672 if seen_bindings.contains_key(&ident) {
2673 let span = seen_bindings.get(&ident).unwrap();
2674 let err = ResolutionError::NameAlreadyUsedInParameterList(
2678 resolve_error(self, param.ident.span, err);
2680 seen_bindings.entry(ident).or_insert(param.ident.span);
2683 DefKind::ConstParam,
2684 self.definitions.local_def_id(param.id),
2686 function_value_rib.bindings.insert(ident, res);
2687 self.record_partial_res(param.id, PartialRes::new(res));
2691 self.ribs[ValueNS].push(function_value_rib);
2692 self.ribs[TypeNS].push(function_type_rib);
2695 NoGenericParams => {
2702 if let HasGenericParams(..) = generic_params {
2703 self.ribs[TypeNS].pop();
2704 self.ribs[ValueNS].pop();
2708 fn with_label_rib<F>(&mut self, f: F)
2709 where F: FnOnce(&mut Resolver<'_>)
2711 self.label_ribs.push(Rib::new(NormalRibKind));
2713 self.label_ribs.pop();
2716 fn with_item_rib<F>(&mut self, f: F)
2717 where F: FnOnce(&mut Resolver<'_>)
2719 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2720 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2722 self.ribs[TypeNS].pop();
2723 self.ribs[ValueNS].pop();
2726 fn with_constant_rib<F>(&mut self, f: F)
2727 where F: FnOnce(&mut Resolver<'_>)
2729 debug!("with_constant_rib");
2730 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2731 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2733 self.label_ribs.pop();
2734 self.ribs[ValueNS].pop();
2737 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2738 where F: FnOnce(&mut Resolver<'_>) -> T
2740 // Handle nested impls (inside fn bodies)
2741 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2742 let result = f(self);
2743 self.current_self_type = previous_value;
2747 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2748 where F: FnOnce(&mut Resolver<'_>) -> T
2750 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2751 let result = f(self);
2752 self.current_self_item = previous_value;
2756 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2757 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2758 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2760 let mut new_val = None;
2761 let mut new_id = None;
2762 if let Some(trait_ref) = opt_trait_ref {
2763 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2764 let res = self.smart_resolve_path_fragment(
2768 trait_ref.path.span,
2769 PathSource::Trait(AliasPossibility::No),
2770 CrateLint::SimplePath(trait_ref.ref_id),
2772 if res != Res::Err {
2773 new_id = Some(res.def_id());
2774 let span = trait_ref.path.span;
2775 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2776 self.resolve_path_without_parent_scope(
2781 CrateLint::SimplePath(trait_ref.ref_id),
2784 new_val = Some((module, trait_ref.clone()));
2788 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2789 let result = f(self, new_id);
2790 self.current_trait_ref = original_trait_ref;
2794 fn with_self_rib<F>(&mut self, self_res: Res, f: F)
2795 where F: FnOnce(&mut Resolver<'_>)
2797 let mut self_type_rib = Rib::new(NormalRibKind);
2799 // Plain insert (no renaming, since types are not currently hygienic)
2800 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2801 self.ribs[TypeNS].push(self_type_rib);
2803 self.ribs[TypeNS].pop();
2806 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2807 where F: FnOnce(&mut Resolver<'_>)
2809 let self_res = Res::SelfCtor(impl_id);
2810 let mut self_type_rib = Rib::new(NormalRibKind);
2811 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2812 self.ribs[ValueNS].push(self_type_rib);
2814 self.ribs[ValueNS].pop();
2817 fn resolve_implementation(&mut self,
2818 generics: &Generics,
2819 opt_trait_reference: &Option<TraitRef>,
2822 impl_items: &[ImplItem]) {
2823 debug!("resolve_implementation");
2824 // If applicable, create a rib for the type parameters.
2825 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2826 // Dummy self type for better errors if `Self` is used in the trait path.
2827 this.with_self_rib(Res::SelfTy(None, None), |this| {
2828 // Resolve the trait reference, if necessary.
2829 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2830 let item_def_id = this.definitions.local_def_id(item_id);
2831 this.with_self_rib(Res::SelfTy(trait_id, Some(item_def_id)), |this| {
2832 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2833 // Resolve type arguments in the trait path.
2834 visit::walk_trait_ref(this, trait_ref);
2836 // Resolve the self type.
2837 this.visit_ty(self_type);
2838 // Resolve the generic parameters.
2839 this.visit_generics(generics);
2840 // Resolve the items within the impl.
2841 this.with_current_self_type(self_type, |this| {
2842 this.with_self_struct_ctor_rib(item_def_id, |this| {
2843 debug!("resolve_implementation with_self_struct_ctor_rib");
2844 for impl_item in impl_items {
2845 this.resolve_visibility(&impl_item.vis);
2847 // We also need a new scope for the impl item type parameters.
2848 let generic_params = HasGenericParams(&impl_item.generics,
2850 this.with_generic_param_rib(generic_params, |this| {
2851 use self::ResolutionError::*;
2852 match impl_item.node {
2853 ImplItemKind::Const(..) => {
2855 "resolve_implementation ImplItemKind::Const",
2857 // If this is a trait impl, ensure the const
2859 this.check_trait_item(
2863 |n, s| ConstNotMemberOfTrait(n, s),
2866 this.with_constant_rib(|this| {
2867 visit::walk_impl_item(this, impl_item)
2870 ImplItemKind::Method(..) => {
2871 // If this is a trait impl, ensure the method
2873 this.check_trait_item(impl_item.ident,
2876 |n, s| MethodNotMemberOfTrait(n, s));
2878 visit::walk_impl_item(this, impl_item);
2880 ImplItemKind::Type(ref ty) => {
2881 // If this is a trait impl, ensure the type
2883 this.check_trait_item(impl_item.ident,
2886 |n, s| TypeNotMemberOfTrait(n, s));
2890 ImplItemKind::Existential(ref bounds) => {
2891 // If this is a trait impl, ensure the type
2893 this.check_trait_item(impl_item.ident,
2896 |n, s| TypeNotMemberOfTrait(n, s));
2898 for bound in bounds {
2899 this.visit_param_bound(bound);
2902 ImplItemKind::Macro(_) =>
2903 panic!("unexpanded macro in resolve!"),
2915 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2916 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2918 // If there is a TraitRef in scope for an impl, then the method must be in the
2920 if let Some((module, _)) = self.current_trait_ref {
2921 if self.resolve_ident_in_module(
2922 ModuleOrUniformRoot::Module(module),
2929 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2930 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2935 fn resolve_local(&mut self, local: &Local) {
2936 // Resolve the type.
2937 walk_list!(self, visit_ty, &local.ty);
2939 // Resolve the initializer.
2940 walk_list!(self, visit_expr, &local.init);
2942 // Resolve the pattern.
2943 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2946 // build a map from pattern identifiers to binding-info's.
2947 // this is done hygienically. This could arise for a macro
2948 // that expands into an or-pattern where one 'x' was from the
2949 // user and one 'x' came from the macro.
2950 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2951 let mut binding_map = FxHashMap::default();
2953 pat.walk(&mut |pat| {
2954 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2955 if sub_pat.is_some() || match self.partial_res_map.get(&pat.id)
2956 .map(|res| res.base_res()) {
2957 Some(Res::Local(..)) => true,
2960 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2961 binding_map.insert(ident, binding_info);
2970 // check that all of the arms in an or-pattern have exactly the
2971 // same set of bindings, with the same binding modes for each.
2972 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2973 if pats.is_empty() {
2977 let mut missing_vars = FxHashMap::default();
2978 let mut inconsistent_vars = FxHashMap::default();
2979 for (i, p) in pats.iter().enumerate() {
2980 let map_i = self.binding_mode_map(&p);
2982 for (j, q) in pats.iter().enumerate() {
2987 let map_j = self.binding_mode_map(&q);
2988 for (&key, &binding_i) in &map_i {
2989 if map_j.is_empty() { // Account for missing bindings when
2990 let binding_error = missing_vars // map_j has none.
2992 .or_insert(BindingError {
2994 origin: BTreeSet::new(),
2995 target: BTreeSet::new(),
2997 binding_error.origin.insert(binding_i.span);
2998 binding_error.target.insert(q.span);
3000 for (&key_j, &binding_j) in &map_j {
3001 match map_i.get(&key_j) {
3002 None => { // missing binding
3003 let binding_error = missing_vars
3005 .or_insert(BindingError {
3007 origin: BTreeSet::new(),
3008 target: BTreeSet::new(),
3010 binding_error.origin.insert(binding_j.span);
3011 binding_error.target.insert(p.span);
3013 Some(binding_i) => { // check consistent binding
3014 if binding_i.binding_mode != binding_j.binding_mode {
3017 .or_insert((binding_j.span, binding_i.span));
3025 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
3026 missing_vars.sort();
3027 for (_, v) in missing_vars {
3029 *v.origin.iter().next().unwrap(),
3030 ResolutionError::VariableNotBoundInPattern(v));
3032 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
3033 inconsistent_vars.sort();
3034 for (name, v) in inconsistent_vars {
3035 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
3039 fn resolve_arm(&mut self, arm: &Arm) {
3040 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3042 let mut bindings_list = FxHashMap::default();
3043 for pattern in &arm.pats {
3044 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
3047 // This has to happen *after* we determine which pat_idents are variants.
3048 self.check_consistent_bindings(&arm.pats);
3050 if let Some(ast::Guard::If(ref expr)) = arm.guard {
3051 self.visit_expr(expr)
3053 self.visit_expr(&arm.body);
3055 self.ribs[ValueNS].pop();
3058 fn resolve_block(&mut self, block: &Block) {
3059 debug!("(resolving block) entering block");
3060 // Move down in the graph, if there's an anonymous module rooted here.
3061 let orig_module = self.current_module;
3062 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
3064 let mut num_macro_definition_ribs = 0;
3065 if let Some(anonymous_module) = anonymous_module {
3066 debug!("(resolving block) found anonymous module, moving down");
3067 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3068 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3069 self.current_module = anonymous_module;
3070 self.finalize_current_module_macro_resolutions();
3072 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3075 // Descend into the block.
3076 for stmt in &block.stmts {
3077 if let ast::StmtKind::Item(ref item) = stmt.node {
3078 if let ast::ItemKind::MacroDef(..) = item.node {
3079 num_macro_definition_ribs += 1;
3080 let res = self.definitions.local_def_id(item.id);
3081 self.ribs[ValueNS].push(Rib::new(MacroDefinition(res)));
3082 self.label_ribs.push(Rib::new(MacroDefinition(res)));
3086 self.visit_stmt(stmt);
3090 self.current_module = orig_module;
3091 for _ in 0 .. num_macro_definition_ribs {
3092 self.ribs[ValueNS].pop();
3093 self.label_ribs.pop();
3095 self.ribs[ValueNS].pop();
3096 if anonymous_module.is_some() {
3097 self.ribs[TypeNS].pop();
3099 debug!("(resolving block) leaving block");
3102 fn fresh_binding(&mut self,
3105 outer_pat_id: NodeId,
3106 pat_src: PatternSource,
3107 bindings: &mut FxHashMap<Ident, NodeId>)
3109 // Add the binding to the local ribs, if it
3110 // doesn't already exist in the bindings map. (We
3111 // must not add it if it's in the bindings map
3112 // because that breaks the assumptions later
3113 // passes make about or-patterns.)
3114 let ident = ident.modern_and_legacy();
3115 let mut res = Res::Local(pat_id);
3116 match bindings.get(&ident).cloned() {
3117 Some(id) if id == outer_pat_id => {
3118 // `Variant(a, a)`, error
3122 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3126 Some(..) if pat_src == PatternSource::FnParam => {
3127 // `fn f(a: u8, a: u8)`, error
3131 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3135 Some(..) if pat_src == PatternSource::Match ||
3136 pat_src == PatternSource::IfLet ||
3137 pat_src == PatternSource::WhileLet => {
3138 // `Variant1(a) | Variant2(a)`, ok
3139 // Reuse definition from the first `a`.
3140 res = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3143 span_bug!(ident.span, "two bindings with the same name from \
3144 unexpected pattern source {:?}", pat_src);
3147 // A completely fresh binding, add to the lists if it's valid.
3148 if ident.name != kw::Invalid {
3149 bindings.insert(ident, outer_pat_id);
3150 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, res);
3158 fn resolve_pattern(&mut self,
3160 pat_src: PatternSource,
3161 // Maps idents to the node ID for the
3162 // outermost pattern that binds them.
3163 bindings: &mut FxHashMap<Ident, NodeId>) {
3164 // Visit all direct subpatterns of this pattern.
3165 let outer_pat_id = pat.id;
3166 pat.walk(&mut |pat| {
3167 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3169 PatKind::Ident(bmode, ident, ref opt_pat) => {
3170 // First try to resolve the identifier as some existing
3171 // entity, then fall back to a fresh binding.
3172 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3174 .and_then(LexicalScopeBinding::item);
3175 let res = binding.map(NameBinding::res).and_then(|res| {
3176 let is_syntactic_ambiguity = opt_pat.is_none() &&
3177 bmode == BindingMode::ByValue(Mutability::Immutable);
3179 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
3180 Res::Def(DefKind::Const, _) if is_syntactic_ambiguity => {
3181 // Disambiguate in favor of a unit struct/variant
3182 // or constant pattern.
3183 self.record_use(ident, ValueNS, binding.unwrap(), false);
3186 Res::Def(DefKind::Ctor(..), _)
3187 | Res::Def(DefKind::Const, _)
3188 | Res::Def(DefKind::Static, _) => {
3189 // This is unambiguously a fresh binding, either syntactically
3190 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3191 // to something unusable as a pattern (e.g., constructor function),
3192 // but we still conservatively report an error, see
3193 // issues/33118#issuecomment-233962221 for one reason why.
3197 ResolutionError::BindingShadowsSomethingUnacceptable(
3198 pat_src.descr(), ident.name, binding.unwrap())
3202 Res::Def(DefKind::Fn, _) | Res::Err => {
3203 // These entities are explicitly allowed
3204 // to be shadowed by fresh bindings.
3208 span_bug!(ident.span, "unexpected resolution for an \
3209 identifier in pattern: {:?}", res);
3212 }).unwrap_or_else(|| {
3213 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3216 self.record_partial_res(pat.id, PartialRes::new(res));
3219 PatKind::TupleStruct(ref path, ..) => {
3220 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3223 PatKind::Path(ref qself, ref path) => {
3224 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3227 PatKind::Struct(ref path, ..) => {
3228 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3236 visit::walk_pat(self, pat);
3239 // High-level and context dependent path resolution routine.
3240 // Resolves the path and records the resolution into definition map.
3241 // If resolution fails tries several techniques to find likely
3242 // resolution candidates, suggest imports or other help, and report
3243 // errors in user friendly way.
3244 fn smart_resolve_path(&mut self,
3246 qself: Option<&QSelf>,
3248 source: PathSource<'_>) {
3249 self.smart_resolve_path_fragment(
3252 &Segment::from_path(path),
3255 CrateLint::SimplePath(id),
3259 fn smart_resolve_path_fragment(&mut self,
3261 qself: Option<&QSelf>,
3264 source: PathSource<'_>,
3265 crate_lint: CrateLint)
3267 let ns = source.namespace();
3268 let is_expected = &|res| source.is_expected(res);
3270 let report_errors = |this: &mut Self, res: Option<Res>| {
3271 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, res);
3272 let def_id = this.current_module.normal_ancestor_id;
3273 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3274 let better = res.is_some();
3275 this.use_injections.push(UseError { err, candidates, node_id, better });
3276 PartialRes::new(Res::Err)
3279 let partial_res = match self.resolve_qpath_anywhere(
3285 source.defer_to_typeck(),
3286 source.global_by_default(),
3289 Some(partial_res) if partial_res.unresolved_segments() == 0 => {
3290 if is_expected(partial_res.base_res()) || partial_res.base_res() == Res::Err {
3293 // Add a temporary hack to smooth the transition to new struct ctor
3294 // visibility rules. See #38932 for more details.
3296 if let Res::Def(DefKind::Struct, def_id) = partial_res.base_res() {
3297 if let Some((ctor_res, ctor_vis))
3298 = self.struct_constructors.get(&def_id).cloned() {
3299 if is_expected(ctor_res) && self.is_accessible(ctor_vis) {
3300 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3301 self.session.buffer_lint(lint, id, span,
3302 "private struct constructors are not usable through \
3303 re-exports in outer modules",
3305 res = Some(PartialRes::new(ctor_res));
3310 res.unwrap_or_else(|| report_errors(self, Some(partial_res.base_res())))
3313 Some(partial_res) if source.defer_to_typeck() => {
3314 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3315 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3316 // it needs to be added to the trait map.
3318 let item_name = path.last().unwrap().ident;
3319 let traits = self.get_traits_containing_item(item_name, ns);
3320 self.trait_map.insert(id, traits);
3323 let mut std_path = vec![Segment::from_ident(Ident::with_empty_ctxt(sym::std))];
3324 std_path.extend(path);
3325 if self.primitive_type_table.primitive_types.contains_key(&path[0].ident.name) {
3326 let cl = CrateLint::No;
3328 if let PathResult::Module(_) | PathResult::NonModule(_) =
3329 self.resolve_path_without_parent_scope(&std_path, ns, false, span, cl)
3331 // check if we wrote `str::from_utf8` instead of `std::str::from_utf8`
3332 let item_span = path.iter().last().map(|segment| segment.ident.span)
3334 debug!("accessed item from `std` submodule as a bare type {:?}", std_path);
3335 let mut hm = self.session.confused_type_with_std_module.borrow_mut();
3336 hm.insert(item_span, span);
3337 // In some places (E0223) we only have access to the full path
3338 hm.insert(span, span);
3343 _ => report_errors(self, None)
3346 if let PathSource::TraitItem(..) = source {} else {
3347 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3348 self.record_partial_res(id, partial_res);
3353 /// Only used in a specific case of type ascription suggestions
3355 fn get_colon_suggestion_span(&self, start: Span) -> Span {
3356 let cm = self.session.source_map();
3357 start.to(cm.next_point(start))
3360 fn type_ascription_suggestion(
3362 err: &mut DiagnosticBuilder<'_>,
3365 debug!("type_ascription_suggetion {:?}", base_span);
3366 let cm = self.session.source_map();
3367 let base_snippet = cm.span_to_snippet(base_span);
3368 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3369 if let Some(sp) = self.current_type_ascription.last() {
3372 // Try to find the `:`; bail on first non-':' / non-whitespace.
3373 sp = cm.next_point(sp);
3374 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3375 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3376 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3378 let mut show_label = true;
3379 if line_sp != line_base_sp {
3380 err.span_suggestion_short(
3382 "did you mean to use `;` here instead?",
3384 Applicability::MaybeIncorrect,
3387 let colon_sp = self.get_colon_suggestion_span(sp);
3388 let after_colon_sp = self.get_colon_suggestion_span(
3389 colon_sp.shrink_to_hi(),
3391 if !cm.span_to_snippet(after_colon_sp).map(|s| s == " ")
3394 err.span_suggestion(
3396 "maybe you meant to write a path separator here",
3398 Applicability::MaybeIncorrect,
3402 if let Ok(base_snippet) = base_snippet {
3403 let mut sp = after_colon_sp;
3405 // Try to find an assignment
3406 sp = cm.next_point(sp);
3407 let snippet = cm.span_to_snippet(sp.to(cm.next_point(sp)));
3409 Ok(ref x) if x.as_str() == "=" => {
3410 err.span_suggestion(
3412 "maybe you meant to write an assignment here",
3413 format!("let {}", base_snippet),
3414 Applicability::MaybeIncorrect,
3419 Ok(ref x) if x.as_str() == "\n" => break,
3427 err.span_label(base_span,
3428 "expecting a type here because of type ascription");
3431 } else if !snippet.trim().is_empty() {
3432 debug!("tried to find type ascription `:` token, couldn't find it");
3442 fn self_type_is_available(&mut self, span: Span) -> bool {
3443 let binding = self.resolve_ident_in_lexical_scope(Ident::with_empty_ctxt(kw::SelfUpper),
3444 TypeNS, None, span);
3445 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3448 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3449 let ident = Ident::new(kw::SelfLower, self_span);
3450 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3451 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3454 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3455 fn resolve_qpath_anywhere(
3458 qself: Option<&QSelf>,
3460 primary_ns: Namespace,
3462 defer_to_typeck: bool,
3463 global_by_default: bool,
3464 crate_lint: CrateLint,
3465 ) -> Option<PartialRes> {
3466 let mut fin_res = None;
3467 // FIXME: can't resolve paths in macro namespace yet, macros are
3468 // processed by the little special hack below.
3469 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3470 if i == 0 || ns != primary_ns {
3471 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3472 // If defer_to_typeck, then resolution > no resolution,
3473 // otherwise full resolution > partial resolution > no resolution.
3474 Some(partial_res) if partial_res.unresolved_segments() == 0 ||
3476 return Some(partial_res),
3477 partial_res => if fin_res.is_none() { fin_res = partial_res },
3481 if primary_ns != MacroNS &&
3482 (self.macro_names.contains(&path[0].ident.modern()) ||
3483 self.builtin_macros.get(&path[0].ident.name).cloned()
3484 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3485 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3486 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3487 // Return some dummy definition, it's enough for error reporting.
3488 return Some(PartialRes::new(Res::Def(
3489 DefKind::Macro(MacroKind::Bang),
3490 DefId::local(CRATE_DEF_INDEX),
3496 /// Handles paths that may refer to associated items.
3500 qself: Option<&QSelf>,
3504 global_by_default: bool,
3505 crate_lint: CrateLint,
3506 ) -> Option<PartialRes> {
3508 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3509 ns={:?}, span={:?}, global_by_default={:?})",
3518 if let Some(qself) = qself {
3519 if qself.position == 0 {
3520 // This is a case like `<T>::B`, where there is no
3521 // trait to resolve. In that case, we leave the `B`
3522 // segment to be resolved by type-check.
3523 return Some(PartialRes::with_unresolved_segments(
3524 Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX)), path.len()
3528 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3530 // Currently, `path` names the full item (`A::B::C`, in
3531 // our example). so we extract the prefix of that that is
3532 // the trait (the slice upto and including
3533 // `qself.position`). And then we recursively resolve that,
3534 // but with `qself` set to `None`.
3536 // However, setting `qself` to none (but not changing the
3537 // span) loses the information about where this path
3538 // *actually* appears, so for the purposes of the crate
3539 // lint we pass along information that this is the trait
3540 // name from a fully qualified path, and this also
3541 // contains the full span (the `CrateLint::QPathTrait`).
3542 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3543 let partial_res = self.smart_resolve_path_fragment(
3546 &path[..=qself.position],
3548 PathSource::TraitItem(ns),
3549 CrateLint::QPathTrait {
3551 qpath_span: qself.path_span,
3555 // The remaining segments (the `C` in our example) will
3556 // have to be resolved by type-check, since that requires doing
3557 // trait resolution.
3558 return Some(PartialRes::with_unresolved_segments(
3559 partial_res.base_res(),
3560 partial_res.unresolved_segments() + path.len() - qself.position - 1,
3564 let result = match self.resolve_path_without_parent_scope(
3571 PathResult::NonModule(path_res) => path_res,
3572 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3573 PartialRes::new(module.res().unwrap())
3575 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3576 // don't report an error right away, but try to fallback to a primitive type.
3577 // So, we are still able to successfully resolve something like
3579 // use std::u8; // bring module u8 in scope
3580 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3581 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3582 // // not to non-existent std::u8::max_value
3585 // Such behavior is required for backward compatibility.
3586 // The same fallback is used when `a` resolves to nothing.
3587 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3588 PathResult::Failed { .. }
3589 if (ns == TypeNS || path.len() > 1) &&
3590 self.primitive_type_table.primitive_types
3591 .contains_key(&path[0].ident.name) => {
3592 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3593 PartialRes::with_unresolved_segments(Res::PrimTy(prim), path.len() - 1)
3595 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3596 PartialRes::new(module.res().unwrap()),
3597 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
3598 resolve_error(self, span, ResolutionError::FailedToResolve { label, suggestion });
3599 PartialRes::new(Res::Err)
3601 PathResult::Module(..) | PathResult::Failed { .. } => return None,
3602 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3605 if path.len() > 1 && !global_by_default && result.base_res() != Res::Err &&
3606 path[0].ident.name != kw::PathRoot &&
3607 path[0].ident.name != kw::DollarCrate {
3608 let unqualified_result = {
3609 match self.resolve_path_without_parent_scope(
3610 &[*path.last().unwrap()],
3616 PathResult::NonModule(path_res) => path_res.base_res(),
3617 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3618 module.res().unwrap(),
3619 _ => return Some(result),
3622 if result.base_res() == unqualified_result {
3623 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3624 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3631 fn resolve_path_without_parent_scope(
3634 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3637 crate_lint: CrateLint,
3638 ) -> PathResult<'a> {
3639 // Macro and import paths must have full parent scope available during resolution,
3640 // other paths will do okay with parent module alone.
3641 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3642 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3643 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3649 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3650 parent_scope: &ParentScope<'a>,
3653 crate_lint: CrateLint,
3654 ) -> PathResult<'a> {
3655 let mut module = None;
3656 let mut allow_super = true;
3657 let mut second_binding = None;
3658 self.current_module = parent_scope.module;
3661 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3662 path_span={:?}, crate_lint={:?})",
3670 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3671 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3672 let record_segment_res = |this: &mut Self, res| {
3674 if let Some(id) = id {
3675 if !this.partial_res_map.contains_key(&id) {
3676 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3677 this.record_partial_res(id, PartialRes::new(res));
3683 let is_last = i == path.len() - 1;
3684 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3685 let name = ident.name;
3687 allow_super &= ns == TypeNS &&
3688 (name == kw::SelfLower ||
3692 if allow_super && name == kw::Super {
3693 let mut ctxt = ident.span.ctxt().modern();
3694 let self_module = match i {
3695 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3697 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3701 if let Some(self_module) = self_module {
3702 if let Some(parent) = self_module.parent {
3703 module = Some(ModuleOrUniformRoot::Module(
3704 self.resolve_self(&mut ctxt, parent)));
3708 let msg = "there are too many initial `super`s.".to_string();
3709 return PathResult::Failed {
3713 is_error_from_last_segment: false,
3717 if name == kw::SelfLower {
3718 let mut ctxt = ident.span.ctxt().modern();
3719 module = Some(ModuleOrUniformRoot::Module(
3720 self.resolve_self(&mut ctxt, self.current_module)));
3723 if name == kw::PathRoot && ident.span.rust_2018() {
3724 module = Some(ModuleOrUniformRoot::ExternPrelude);
3727 if name == kw::PathRoot &&
3728 ident.span.rust_2015() && self.session.rust_2018() {
3729 // `::a::b` from 2015 macro on 2018 global edition
3730 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3733 if name == kw::PathRoot ||
3734 name == kw::Crate ||
3735 name == kw::DollarCrate {
3736 // `::a::b`, `crate::a::b` or `$crate::a::b`
3737 module = Some(ModuleOrUniformRoot::Module(
3738 self.resolve_crate_root(ident)));
3744 // Report special messages for path segment keywords in wrong positions.
3745 if ident.is_path_segment_keyword() && i != 0 {
3746 let name_str = if name == kw::PathRoot {
3747 "crate root".to_string()
3749 format!("`{}`", name)
3751 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
3752 format!("global paths cannot start with {}", name_str)
3754 format!("{} in paths can only be used in start position", name_str)
3756 return PathResult::Failed {
3760 is_error_from_last_segment: false,
3764 let binding = if let Some(module) = module {
3765 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3766 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3767 assert!(ns == TypeNS);
3768 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3769 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3770 record_used, path_span)
3772 let record_used_id =
3773 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3774 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3775 // we found a locally-imported or available item/module
3776 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3777 // we found a local variable or type param
3778 Some(LexicalScopeBinding::Res(res))
3779 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3780 record_segment_res(self, res);
3781 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3785 _ => Err(Determinacy::determined(record_used)),
3792 second_binding = Some(binding);
3794 let res = binding.res();
3795 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
3796 if let Some(next_module) = binding.module() {
3797 module = Some(ModuleOrUniformRoot::Module(next_module));
3798 record_segment_res(self, res);
3799 } else if res == Res::ToolMod && i + 1 != path.len() {
3800 if binding.is_import() {
3801 self.session.struct_span_err(
3802 ident.span, "cannot use a tool module through an import"
3804 binding.span, "the tool module imported here"
3807 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
3808 return PathResult::NonModule(PartialRes::new(res));
3809 } else if res == Res::Err {
3810 return PathResult::NonModule(PartialRes::new(Res::Err));
3811 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3812 self.lint_if_path_starts_with_module(
3818 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3819 res, path.len() - i - 1
3822 let label = format!(
3823 "`{}` is {} {}, not a module",
3829 return PathResult::Failed {
3833 is_error_from_last_segment: is_last,
3837 Err(Undetermined) => return PathResult::Indeterminate,
3838 Err(Determined) => {
3839 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3840 if opt_ns.is_some() && !module.is_normal() {
3841 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3842 module.res().unwrap(), path.len() - i
3846 let module_res = match module {
3847 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
3850 let (label, suggestion) = if module_res == self.graph_root.res() {
3851 let is_mod = |res| {
3852 match res { Res::Def(DefKind::Mod, _) => true, _ => false }
3854 let mut candidates =
3855 self.lookup_import_candidates(ident, TypeNS, is_mod);
3856 candidates.sort_by_cached_key(|c| {
3857 (c.path.segments.len(), c.path.to_string())
3859 if let Some(candidate) = candidates.get(0) {
3861 String::from("unresolved import"),
3863 vec![(ident.span, candidate.path.to_string())],
3864 String::from("a similar path exists"),
3865 Applicability::MaybeIncorrect,
3868 } else if !ident.is_reserved() {
3869 (format!("maybe a missing `extern crate {};`?", ident), None)
3871 // the parser will already have complained about the keyword being used
3872 return PathResult::NonModule(PartialRes::new(Res::Err));
3875 (format!("use of undeclared type or module `{}`", ident), None)
3877 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
3879 return PathResult::Failed {
3883 is_error_from_last_segment: is_last,
3889 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3891 PathResult::Module(match module {
3892 Some(module) => module,
3893 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3894 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3898 fn lint_if_path_starts_with_module(
3900 crate_lint: CrateLint,
3903 second_binding: Option<&NameBinding<'_>>,
3905 let (diag_id, diag_span) = match crate_lint {
3906 CrateLint::No => return,
3907 CrateLint::SimplePath(id) => (id, path_span),
3908 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3909 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3912 let first_name = match path.get(0) {
3913 // In the 2018 edition this lint is a hard error, so nothing to do
3914 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3918 // We're only interested in `use` paths which should start with
3919 // `{{root}}` currently.
3920 if first_name != kw::PathRoot {
3925 // If this import looks like `crate::...` it's already good
3926 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
3927 // Otherwise go below to see if it's an extern crate
3929 // If the path has length one (and it's `PathRoot` most likely)
3930 // then we don't know whether we're gonna be importing a crate or an
3931 // item in our crate. Defer this lint to elsewhere
3935 // If the first element of our path was actually resolved to an
3936 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3937 // warning, this looks all good!
3938 if let Some(binding) = second_binding {
3939 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3940 // Careful: we still want to rewrite paths from
3941 // renamed extern crates.
3942 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3948 let diag = lint::builtin::BuiltinLintDiagnostics
3949 ::AbsPathWithModule(diag_span);
3950 self.session.buffer_lint_with_diagnostic(
3951 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3953 "absolute paths must start with `self`, `super`, \
3954 `crate`, or an external crate name in the 2018 edition",
3958 // Validate a local resolution (from ribs).
3959 fn validate_res_from_ribs(
3967 debug!("validate_res_from_ribs({:?})", res);
3968 let ribs = &self.ribs[ns][rib_index + 1..];
3970 // An invalid forward use of a type parameter from a previous default.
3971 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3973 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3975 assert_eq!(res, Res::Err);
3979 // An invalid use of a type parameter as the type of a const parameter.
3980 if let TyParamAsConstParamTy = self.ribs[ns][rib_index].kind {
3982 resolve_error(self, span, ResolutionError::ConstParamDependentOnTypeParam);
3984 assert_eq!(res, Res::Err);
3990 use ResolutionError::*;
3991 let mut res_err = None;
3995 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3996 ForwardTyParamBanRibKind | TyParamAsConstParamTy => {
3997 // Nothing to do. Continue.
3999 ItemRibKind | FnItemRibKind | AssocItemRibKind => {
4000 // This was an attempt to access an upvar inside a
4001 // named function item. This is not allowed, so we
4004 // We don't immediately trigger a resolve error, because
4005 // we want certain other resolution errors (namely those
4006 // emitted for `ConstantItemRibKind` below) to take
4008 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
4011 ConstantItemRibKind => {
4012 // Still doesn't deal with upvars
4014 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
4020 if let Some(res_err) = res_err {
4021 resolve_error(self, span, res_err);
4025 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
4028 NormalRibKind | AssocItemRibKind |
4029 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4030 ConstantItemRibKind | TyParamAsConstParamTy => {
4031 // Nothing to do. Continue.
4033 ItemRibKind | FnItemRibKind => {
4034 // This was an attempt to use a type parameter outside its scope.
4039 ResolutionError::GenericParamsFromOuterFunction(res),
4047 Res::Def(DefKind::ConstParam, _) => {
4048 let mut ribs = ribs.iter().peekable();
4049 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
4050 // When declaring const parameters inside function signatures, the first rib
4051 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
4052 // (spuriously) conflicting with the const param.
4056 if let ItemRibKind | FnItemRibKind = rib.kind {
4057 // This was an attempt to use a const parameter outside its scope.
4062 ResolutionError::GenericParamsFromOuterFunction(res),
4074 fn lookup_assoc_candidate<FilterFn>(&mut self,
4077 filter_fn: FilterFn)
4078 -> Option<AssocSuggestion>
4079 where FilterFn: Fn(Res) -> bool
4081 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4083 TyKind::Path(None, _) => Some(t.id),
4084 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4085 // This doesn't handle the remaining `Ty` variants as they are not
4086 // that commonly the self_type, it might be interesting to provide
4087 // support for those in future.
4092 // Fields are generally expected in the same contexts as locals.
4093 if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
4094 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4095 // Look for a field with the same name in the current self_type.
4096 if let Some(resolution) = self.partial_res_map.get(&node_id) {
4097 match resolution.base_res() {
4098 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did)
4099 if resolution.unresolved_segments() == 0 => {
4100 if let Some(field_names) = self.field_names.get(&did) {
4101 if field_names.iter().any(|&field_name| ident.name == field_name) {
4102 return Some(AssocSuggestion::Field);
4112 // Look for associated items in the current trait.
4113 if let Some((module, _)) = self.current_trait_ref {
4114 if let Ok(binding) = self.resolve_ident_in_module(
4115 ModuleOrUniformRoot::Module(module),
4122 let res = binding.res();
4124 return Some(if self.has_self.contains(&res.def_id()) {
4125 AssocSuggestion::MethodWithSelf
4127 AssocSuggestion::AssocItem
4136 fn lookup_typo_candidate<FilterFn>(
4140 filter_fn: FilterFn,
4142 ) -> Option<TypoSuggestion>
4144 FilterFn: Fn(Res) -> bool,
4146 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4147 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4148 if let Some(binding) = resolution.borrow().binding {
4149 if filter_fn(binding.res()) {
4150 names.push(TypoSuggestion {
4151 candidate: ident.name,
4152 article: binding.res().article(),
4153 kind: binding.res().descr(),
4160 let mut names = Vec::new();
4161 if path.len() == 1 {
4162 // Search in lexical scope.
4163 // Walk backwards up the ribs in scope and collect candidates.
4164 for rib in self.ribs[ns].iter().rev() {
4165 // Locals and type parameters
4166 for (ident, &res) in &rib.bindings {
4168 names.push(TypoSuggestion {
4169 candidate: ident.name,
4170 article: res.article(),
4176 if let ModuleRibKind(module) = rib.kind {
4177 // Items from this module
4178 add_module_candidates(module, &mut names);
4180 if let ModuleKind::Block(..) = module.kind {
4181 // We can see through blocks
4183 // Items from the prelude
4184 if !module.no_implicit_prelude {
4185 names.extend(self.extern_prelude.clone().iter().flat_map(|(ident, _)| {
4187 .maybe_process_path_extern(ident.name, ident.span)
4188 .and_then(|crate_id| {
4189 let crate_mod = Res::Def(
4193 index: CRATE_DEF_INDEX,
4197 if filter_fn(crate_mod) {
4198 Some(TypoSuggestion {
4199 candidate: ident.name,
4209 if let Some(prelude) = self.prelude {
4210 add_module_candidates(prelude, &mut names);
4217 // Add primitive types to the mix
4218 if filter_fn(Res::PrimTy(Bool)) {
4220 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4224 kind: "primitive type",
4230 // Search in module.
4231 let mod_path = &path[..path.len() - 1];
4232 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4233 mod_path, Some(TypeNS), false, span, CrateLint::No
4235 if let ModuleOrUniformRoot::Module(module) = module {
4236 add_module_candidates(module, &mut names);
4241 let name = path[path.len() - 1].ident.name;
4242 // Make sure error reporting is deterministic.
4243 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4245 match find_best_match_for_name(
4246 names.iter().map(|suggestion| &suggestion.candidate),
4250 Some(found) if found != name => names
4252 .find(|suggestion| suggestion.candidate == found),
4257 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4258 where F: FnOnce(&mut Resolver<'_>)
4260 if let Some(label) = label {
4261 self.unused_labels.insert(id, label.ident.span);
4262 self.with_label_rib(|this| {
4263 let ident = label.ident.modern_and_legacy();
4264 this.label_ribs.last_mut().unwrap().bindings.insert(ident, id);
4272 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4273 self.with_resolved_label(label, id, |this| this.visit_block(block));
4276 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4277 // First, record candidate traits for this expression if it could
4278 // result in the invocation of a method call.
4280 self.record_candidate_traits_for_expr_if_necessary(expr);
4282 // Next, resolve the node.
4284 ExprKind::Path(ref qself, ref path) => {
4285 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4286 visit::walk_expr(self, expr);
4289 ExprKind::Struct(ref path, ..) => {
4290 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4291 visit::walk_expr(self, expr);
4294 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4295 let node_id = self.search_label(label.ident, |rib, ident| {
4296 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4300 // Search again for close matches...
4301 // Picks the first label that is "close enough", which is not necessarily
4302 // the closest match
4303 let close_match = self.search_label(label.ident, |rib, ident| {
4304 let names = rib.bindings.iter().filter_map(|(id, _)| {
4305 if id.span.ctxt() == label.ident.span.ctxt() {
4311 find_best_match_for_name(names, &*ident.as_str(), None)
4313 self.record_partial_res(expr.id, PartialRes::new(Res::Err));
4316 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4320 // Since this res is a label, it is never read.
4321 self.label_res_map.insert(expr.id, node_id);
4322 self.unused_labels.remove(&node_id);
4326 // visit `break` argument if any
4327 visit::walk_expr(self, expr);
4330 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4331 self.visit_expr(subexpression);
4333 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4334 let mut bindings_list = FxHashMap::default();
4336 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4338 // This has to happen *after* we determine which pat_idents are variants
4339 self.check_consistent_bindings(pats);
4340 self.visit_block(if_block);
4341 self.ribs[ValueNS].pop();
4343 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4346 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4348 ExprKind::While(ref subexpression, ref block, label) => {
4349 self.with_resolved_label(label, expr.id, |this| {
4350 this.visit_expr(subexpression);
4351 this.visit_block(block);
4355 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4356 self.with_resolved_label(label, expr.id, |this| {
4357 this.visit_expr(subexpression);
4358 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4359 let mut bindings_list = FxHashMap::default();
4361 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4363 // This has to happen *after* we determine which pat_idents are variants.
4364 this.check_consistent_bindings(pats);
4365 this.visit_block(block);
4366 this.ribs[ValueNS].pop();
4370 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4371 self.visit_expr(subexpression);
4372 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4373 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4375 self.resolve_labeled_block(label, expr.id, block);
4377 self.ribs[ValueNS].pop();
4380 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4382 // Equivalent to `visit::walk_expr` + passing some context to children.
4383 ExprKind::Field(ref subexpression, _) => {
4384 self.resolve_expr(subexpression, Some(expr));
4386 ExprKind::MethodCall(ref segment, ref arguments) => {
4387 let mut arguments = arguments.iter();
4388 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4389 for argument in arguments {
4390 self.resolve_expr(argument, None);
4392 self.visit_path_segment(expr.span, segment);
4395 ExprKind::Call(ref callee, ref arguments) => {
4396 self.resolve_expr(callee, Some(expr));
4397 for argument in arguments {
4398 self.resolve_expr(argument, None);
4401 ExprKind::Type(ref type_expr, _) => {
4402 self.current_type_ascription.push(type_expr.span);
4403 visit::walk_expr(self, expr);
4404 self.current_type_ascription.pop();
4406 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4407 // resolve the arguments within the proper scopes so that usages of them inside the
4408 // closure are detected as upvars rather than normal closure arg usages.
4410 _, IsAsync::Async { .. }, _,
4411 ref fn_decl, ref body, _span,
4413 let rib_kind = NormalRibKind;
4414 self.ribs[ValueNS].push(Rib::new(rib_kind));
4415 // Resolve arguments:
4416 let mut bindings_list = FxHashMap::default();
4417 for argument in &fn_decl.inputs {
4418 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4419 self.visit_ty(&argument.ty);
4421 // No need to resolve return type-- the outer closure return type is
4422 // FunctionRetTy::Default
4424 // Now resolve the inner closure
4426 // No need to resolve arguments: the inner closure has none.
4427 // Resolve the return type:
4428 visit::walk_fn_ret_ty(self, &fn_decl.output);
4430 self.visit_expr(body);
4432 self.ribs[ValueNS].pop();
4435 visit::walk_expr(self, expr);
4440 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4442 ExprKind::Field(_, ident) => {
4443 // FIXME(#6890): Even though you can't treat a method like a
4444 // field, we need to add any trait methods we find that match
4445 // the field name so that we can do some nice error reporting
4446 // later on in typeck.
4447 let traits = self.get_traits_containing_item(ident, ValueNS);
4448 self.trait_map.insert(expr.id, traits);
4450 ExprKind::MethodCall(ref segment, ..) => {
4451 debug!("(recording candidate traits for expr) recording traits for {}",
4453 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4454 self.trait_map.insert(expr.id, traits);
4462 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4463 -> Vec<TraitCandidate> {
4464 debug!("(getting traits containing item) looking for '{}'", ident.name);
4466 let mut found_traits = Vec::new();
4467 // Look for the current trait.
4468 if let Some((module, _)) = self.current_trait_ref {
4469 if self.resolve_ident_in_module(
4470 ModuleOrUniformRoot::Module(module),
4477 let def_id = module.def_id().unwrap();
4478 found_traits.push(TraitCandidate { def_id: def_id, import_ids: smallvec![] });
4482 ident.span = ident.span.modern();
4483 let mut search_module = self.current_module;
4485 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4486 search_module = unwrap_or!(
4487 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4491 if let Some(prelude) = self.prelude {
4492 if !search_module.no_implicit_prelude {
4493 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4500 fn get_traits_in_module_containing_item(&mut self,
4504 found_traits: &mut Vec<TraitCandidate>) {
4505 assert!(ns == TypeNS || ns == ValueNS);
4506 let mut traits = module.traits.borrow_mut();
4507 if traits.is_none() {
4508 let mut collected_traits = Vec::new();
4509 module.for_each_child(|name, ns, binding| {
4510 if ns != TypeNS { return }
4511 match binding.res() {
4512 Res::Def(DefKind::Trait, _) |
4513 Res::Def(DefKind::TraitAlias, _) => collected_traits.push((name, binding)),
4517 *traits = Some(collected_traits.into_boxed_slice());
4520 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4521 // Traits have pseudo-modules that can be used to search for the given ident.
4522 if let Some(module) = binding.module() {
4523 let mut ident = ident;
4524 if ident.span.glob_adjust(
4530 if self.resolve_ident_in_module_unadjusted(
4531 ModuleOrUniformRoot::Module(module),
4537 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4538 let trait_def_id = module.def_id().unwrap();
4539 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4541 } else if let Res::Def(DefKind::TraitAlias, _) = binding.res() {
4542 // For now, just treat all trait aliases as possible candidates, since we don't
4543 // know if the ident is somewhere in the transitive bounds.
4544 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4545 let trait_def_id = binding.res().def_id();
4546 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4548 bug!("candidate is not trait or trait alias?")
4553 fn find_transitive_imports(&mut self, mut kind: &NameBindingKind<'_>,
4554 trait_name: Ident) -> SmallVec<[NodeId; 1]> {
4555 let mut import_ids = smallvec![];
4556 while let NameBindingKind::Import { directive, binding, .. } = kind {
4557 self.maybe_unused_trait_imports.insert(directive.id);
4558 self.add_to_glob_map(&directive, trait_name);
4559 import_ids.push(directive.id);
4560 kind = &binding.kind;
4565 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4566 lookup_ident: Ident,
4567 namespace: Namespace,
4568 start_module: &'a ModuleData<'a>,
4570 filter_fn: FilterFn)
4571 -> Vec<ImportSuggestion>
4572 where FilterFn: Fn(Res) -> bool
4574 let mut candidates = Vec::new();
4575 let mut seen_modules = FxHashSet::default();
4576 let not_local_module = crate_name.name != kw::Crate;
4577 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4579 while let Some((in_module,
4581 in_module_is_extern)) = worklist.pop() {
4582 self.populate_module_if_necessary(in_module);
4584 // We have to visit module children in deterministic order to avoid
4585 // instabilities in reported imports (#43552).
4586 in_module.for_each_child_stable(|ident, ns, name_binding| {
4587 // avoid imports entirely
4588 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4589 // avoid non-importable candidates as well
4590 if !name_binding.is_importable() { return; }
4592 // collect results based on the filter function
4593 if ident.name == lookup_ident.name && ns == namespace {
4594 let res = name_binding.res();
4597 let mut segms = path_segments.clone();
4598 if lookup_ident.span.rust_2018() {
4599 // crate-local absolute paths start with `crate::` in edition 2018
4600 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4602 0, ast::PathSegment::from_ident(crate_name)
4606 segms.push(ast::PathSegment::from_ident(ident));
4608 span: name_binding.span,
4611 // the entity is accessible in the following cases:
4612 // 1. if it's defined in the same crate, it's always
4613 // accessible (since private entities can be made public)
4614 // 2. if it's defined in another crate, it's accessible
4615 // only if both the module is public and the entity is
4616 // declared as public (due to pruning, we don't explore
4617 // outside crate private modules => no need to check this)
4618 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4619 let did = match res {
4620 Res::Def(DefKind::Ctor(..), did) => self.parent(did),
4621 _ => res.opt_def_id(),
4623 candidates.push(ImportSuggestion { did, path });
4628 // collect submodules to explore
4629 if let Some(module) = name_binding.module() {
4631 let mut path_segments = path_segments.clone();
4632 path_segments.push(ast::PathSegment::from_ident(ident));
4634 let is_extern_crate_that_also_appears_in_prelude =
4635 name_binding.is_extern_crate() &&
4636 lookup_ident.span.rust_2018();
4638 let is_visible_to_user =
4639 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4641 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4642 // add the module to the lookup
4643 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4644 if seen_modules.insert(module.def_id().unwrap()) {
4645 worklist.push((module, path_segments, is_extern));
4655 /// When name resolution fails, this method can be used to look up candidate
4656 /// entities with the expected name. It allows filtering them using the
4657 /// supplied predicate (which should be used to only accept the types of
4658 /// definitions expected, e.g., traits). The lookup spans across all crates.
4660 /// N.B., the method does not look into imports, but this is not a problem,
4661 /// since we report the definitions (thus, the de-aliased imports).
4662 fn lookup_import_candidates<FilterFn>(&mut self,
4663 lookup_ident: Ident,
4664 namespace: Namespace,
4665 filter_fn: FilterFn)
4666 -> Vec<ImportSuggestion>
4667 where FilterFn: Fn(Res) -> bool
4669 let mut suggestions = self.lookup_import_candidates_from_module(
4670 lookup_ident, namespace, self.graph_root, Ident::with_empty_ctxt(kw::Crate), &filter_fn
4673 if lookup_ident.span.rust_2018() {
4674 let extern_prelude_names = self.extern_prelude.clone();
4675 for (ident, _) in extern_prelude_names.into_iter() {
4676 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4678 let crate_root = self.get_module(DefId {
4680 index: CRATE_DEF_INDEX,
4682 self.populate_module_if_necessary(&crate_root);
4684 suggestions.extend(self.lookup_import_candidates_from_module(
4685 lookup_ident, namespace, crate_root, ident, &filter_fn));
4693 fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
4694 let mut result = None;
4695 let mut seen_modules = FxHashSet::default();
4696 let mut worklist = vec![(self.graph_root, Vec::new())];
4698 while let Some((in_module, path_segments)) = worklist.pop() {
4699 // abort if the module is already found
4700 if result.is_some() { break; }
4702 self.populate_module_if_necessary(in_module);
4704 in_module.for_each_child_stable(|ident, _, name_binding| {
4705 // abort if the module is already found or if name_binding is private external
4706 if result.is_some() || !name_binding.vis.is_visible_locally() {
4709 if let Some(module) = name_binding.module() {
4711 let mut path_segments = path_segments.clone();
4712 path_segments.push(ast::PathSegment::from_ident(ident));
4713 let module_def_id = module.def_id().unwrap();
4714 if module_def_id == def_id {
4716 span: name_binding.span,
4717 segments: path_segments,
4719 result = Some((module, ImportSuggestion { did: Some(def_id), path }));
4721 // add the module to the lookup
4722 if seen_modules.insert(module_def_id) {
4723 worklist.push((module, path_segments));
4733 fn collect_enum_variants(&mut self, def_id: DefId) -> Option<Vec<Path>> {
4734 self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
4735 self.populate_module_if_necessary(enum_module);
4737 let mut variants = Vec::new();
4738 enum_module.for_each_child_stable(|ident, _, name_binding| {
4739 if let Res::Def(DefKind::Variant, _) = name_binding.res() {
4740 let mut segms = enum_import_suggestion.path.segments.clone();
4741 segms.push(ast::PathSegment::from_ident(ident));
4742 variants.push(Path {
4743 span: name_binding.span,
4752 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
4753 debug!("(recording res) recording {:?} for {}", resolution, node_id);
4754 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
4755 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4759 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4761 ast::VisibilityKind::Public => ty::Visibility::Public,
4762 ast::VisibilityKind::Crate(..) => {
4763 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4765 ast::VisibilityKind::Inherited => {
4766 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4768 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4769 // For visibilities we are not ready to provide correct implementation of "uniform
4770 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4771 // On 2015 edition visibilities are resolved as crate-relative by default,
4772 // so we are prepending a root segment if necessary.
4773 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4774 let crate_root = if ident.is_path_segment_keyword() {
4776 } else if ident.span.rust_2018() {
4777 let msg = "relative paths are not supported in visibilities on 2018 edition";
4778 self.session.struct_span_err(ident.span, msg)
4782 format!("crate::{}", path),
4783 Applicability::MaybeIncorrect,
4786 return ty::Visibility::Public;
4788 let ctxt = ident.span.ctxt();
4789 Some(Segment::from_ident(Ident::new(
4790 kw::PathRoot, path.span.shrink_to_lo().with_ctxt(ctxt)
4794 let segments = crate_root.into_iter()
4795 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4796 let res = self.smart_resolve_path_fragment(
4801 PathSource::Visibility,
4802 CrateLint::SimplePath(id),
4804 if res == Res::Err {
4805 ty::Visibility::Public
4807 let vis = ty::Visibility::Restricted(res.def_id());
4808 if self.is_accessible(vis) {
4811 self.session.span_err(path.span, "visibilities can only be restricted \
4812 to ancestor modules");
4813 ty::Visibility::Public
4820 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4821 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4824 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4825 vis.is_accessible_from(module.normal_ancestor_id, self)
4828 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4829 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4830 if !ptr::eq(module, old_module) {
4831 span_bug!(binding.span, "parent module is reset for binding");
4836 fn disambiguate_legacy_vs_modern(
4838 legacy: &'a NameBinding<'a>,
4839 modern: &'a NameBinding<'a>,
4841 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4842 // is disambiguated to mitigate regressions from macro modularization.
4843 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4844 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4845 self.binding_parent_modules.get(&PtrKey(modern))) {
4846 (Some(legacy), Some(modern)) =>
4847 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4848 modern.is_ancestor_of(legacy),
4853 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4854 if b.span.is_dummy() {
4855 let add_built_in = match b.res() {
4856 // These already contain the "built-in" prefix or look bad with it.
4857 Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod => false,
4860 let (built_in, from) = if from_prelude {
4861 ("", " from prelude")
4862 } else if b.is_extern_crate() && !b.is_import() &&
4863 self.session.opts.externs.get(&ident.as_str()).is_some() {
4864 ("", " passed with `--extern`")
4865 } else if add_built_in {
4871 let article = if built_in.is_empty() { b.article() } else { "a" };
4872 format!("{a}{built_in} {thing}{from}",
4873 a = article, thing = b.descr(), built_in = built_in, from = from)
4875 let introduced = if b.is_import() { "imported" } else { "defined" };
4876 format!("the {thing} {introduced} here",
4877 thing = b.descr(), introduced = introduced)
4881 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4882 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4883 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4884 // We have to print the span-less alternative first, otherwise formatting looks bad.
4885 (b2, b1, misc2, misc1, true)
4887 (b1, b2, misc1, misc2, false)
4890 let mut err = struct_span_err!(self.session, ident.span, E0659,
4891 "`{ident}` is ambiguous ({why})",
4892 ident = ident, why = kind.descr());
4893 err.span_label(ident.span, "ambiguous name");
4895 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4896 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4897 let note_msg = format!("`{ident}` could{also} refer to {what}",
4898 ident = ident, also = also, what = what);
4900 let mut help_msgs = Vec::new();
4901 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4902 kind == AmbiguityKind::GlobVsExpanded ||
4903 kind == AmbiguityKind::GlobVsOuter &&
4904 swapped != also.is_empty()) {
4905 help_msgs.push(format!("consider adding an explicit import of \
4906 `{ident}` to disambiguate", ident = ident))
4908 if b.is_extern_crate() && ident.span.rust_2018() {
4909 help_msgs.push(format!(
4910 "use `::{ident}` to refer to this {thing} unambiguously",
4911 ident = ident, thing = b.descr(),
4914 if misc == AmbiguityErrorMisc::SuggestCrate {
4915 help_msgs.push(format!(
4916 "use `crate::{ident}` to refer to this {thing} unambiguously",
4917 ident = ident, thing = b.descr(),
4919 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4920 help_msgs.push(format!(
4921 "use `self::{ident}` to refer to this {thing} unambiguously",
4922 ident = ident, thing = b.descr(),
4926 err.span_note(b.span, ¬e_msg);
4927 for (i, help_msg) in help_msgs.iter().enumerate() {
4928 let or = if i == 0 { "" } else { "or " };
4929 err.help(&format!("{}{}", or, help_msg));
4933 could_refer_to(b1, misc1, "");
4934 could_refer_to(b2, misc2, " also");
4938 fn report_errors(&mut self, krate: &Crate) {
4939 self.report_with_use_injections(krate);
4941 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4942 let msg = "macro-expanded `macro_export` macros from the current crate \
4943 cannot be referred to by absolute paths";
4944 self.session.buffer_lint_with_diagnostic(
4945 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4946 CRATE_NODE_ID, span_use, msg,
4947 lint::builtin::BuiltinLintDiagnostics::
4948 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4952 for ambiguity_error in &self.ambiguity_errors {
4953 self.report_ambiguity_error(ambiguity_error);
4956 let mut reported_spans = FxHashSet::default();
4957 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4958 if reported_spans.insert(dedup_span) {
4959 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4960 binding.descr(), ident.name);
4965 fn report_with_use_injections(&mut self, krate: &Crate) {
4966 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4967 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4968 if !candidates.is_empty() {
4969 show_candidates(&mut err, span, &candidates, better, found_use);
4975 fn report_conflict<'b>(&mut self,
4979 new_binding: &NameBinding<'b>,
4980 old_binding: &NameBinding<'b>) {
4981 // Error on the second of two conflicting names
4982 if old_binding.span.lo() > new_binding.span.lo() {
4983 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4986 let container = match parent.kind {
4987 ModuleKind::Def(DefKind::Mod, _, _) => "module",
4988 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
4989 ModuleKind::Block(..) => "block",
4993 let old_noun = match old_binding.is_import() {
4995 false => "definition",
4998 let new_participle = match new_binding.is_import() {
5003 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5005 if let Some(s) = self.name_already_seen.get(&name) {
5011 let old_kind = match (ns, old_binding.module()) {
5012 (ValueNS, _) => "value",
5013 (MacroNS, _) => "macro",
5014 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5015 (TypeNS, Some(module)) if module.is_normal() => "module",
5016 (TypeNS, Some(module)) if module.is_trait() => "trait",
5017 (TypeNS, _) => "type",
5020 let msg = format!("the name `{}` is defined multiple times", name);
5022 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5023 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5024 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5025 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5026 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5028 _ => match (old_binding.is_import(), new_binding.is_import()) {
5029 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5030 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5031 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5035 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5040 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5042 self.session.source_map().def_span(old_binding.span),
5043 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5046 // See https://github.com/rust-lang/rust/issues/32354
5047 use NameBindingKind::Import;
5048 let directive = match (&new_binding.kind, &old_binding.kind) {
5049 // If there are two imports where one or both have attributes then prefer removing the
5050 // import without attributes.
5051 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5052 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5053 (new.has_attributes || old.has_attributes)
5055 if old.has_attributes {
5056 Some((new, new_binding.span, true))
5058 Some((old, old_binding.span, true))
5061 // Otherwise prioritize the new binding.
5062 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5063 Some((directive, new_binding.span, other.is_import())),
5064 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5065 Some((directive, old_binding.span, other.is_import())),
5069 // Check if the target of the use for both bindings is the same.
5070 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
5071 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5072 let from_item = self.extern_prelude.get(&ident)
5073 .map(|entry| entry.introduced_by_item)
5075 // Only suggest removing an import if both bindings are to the same def, if both spans
5076 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5077 // been introduced by a item.
5078 let should_remove_import = duplicate && !has_dummy_span &&
5079 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5082 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5083 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5084 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5085 // Simple case - remove the entire import. Due to the above match arm, this can
5086 // only be a single use so just remove it entirely.
5087 err.tool_only_span_suggestion(
5088 directive.use_span_with_attributes,
5089 "remove unnecessary import",
5091 Applicability::MaybeIncorrect,
5094 Some((directive, span, _)) =>
5095 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5100 self.name_already_seen.insert(name, span);
5103 /// This function adds a suggestion to change the binding name of a new import that conflicts
5104 /// with an existing import.
5106 /// ```ignore (diagnostic)
5107 /// help: you can use `as` to change the binding name of the import
5109 /// LL | use foo::bar as other_bar;
5110 /// | ^^^^^^^^^^^^^^^^^^^^^
5112 fn add_suggestion_for_rename_of_use(
5114 err: &mut DiagnosticBuilder<'_>,
5116 directive: &ImportDirective<'_>,
5119 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5120 format!("Other{}", name)
5122 format!("other_{}", name)
5125 let mut suggestion = None;
5126 match directive.subclass {
5127 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5128 suggestion = Some(format!("self as {}", suggested_name)),
5129 ImportDirectiveSubclass::SingleImport { source, .. } => {
5130 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5131 .map(|pos| pos as usize) {
5132 if let Ok(snippet) = self.session.source_map()
5133 .span_to_snippet(binding_span) {
5134 if pos <= snippet.len() {
5135 suggestion = Some(format!(
5139 if snippet.ends_with(";") { ";" } else { "" }
5145 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5146 suggestion = Some(format!(
5147 "extern crate {} as {};",
5148 source.unwrap_or(target.name),
5151 _ => unreachable!(),
5154 let rename_msg = "you can use `as` to change the binding name of the import";
5155 if let Some(suggestion) = suggestion {
5156 err.span_suggestion(
5160 Applicability::MaybeIncorrect,
5163 err.span_label(binding_span, rename_msg);
5167 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5168 /// nested. In the following example, this function will be invoked to remove the `a` binding
5169 /// in the second use statement:
5171 /// ```ignore (diagnostic)
5172 /// use issue_52891::a;
5173 /// use issue_52891::{d, a, e};
5176 /// The following suggestion will be added:
5178 /// ```ignore (diagnostic)
5179 /// use issue_52891::{d, a, e};
5180 /// ^-- help: remove unnecessary import
5183 /// If the nested use contains only one import then the suggestion will remove the entire
5186 /// It is expected that the directive provided is a nested import - this isn't checked by the
5187 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5188 /// as characters expected by span manipulations won't be present.
5189 fn add_suggestion_for_duplicate_nested_use(
5191 err: &mut DiagnosticBuilder<'_>,
5192 directive: &ImportDirective<'_>,
5195 assert!(directive.is_nested());
5196 let message = "remove unnecessary import";
5198 // Two examples will be used to illustrate the span manipulations we're doing:
5200 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5201 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5202 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5203 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5205 let (found_closing_brace, span) = find_span_of_binding_until_next_binding(
5206 self.session, binding_span, directive.use_span,
5209 // If there was a closing brace then identify the span to remove any trailing commas from
5210 // previous imports.
5211 if found_closing_brace {
5212 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
5213 err.tool_only_span_suggestion(span, message, String::new(),
5214 Applicability::MaybeIncorrect);
5216 // Remove the entire line if we cannot extend the span back, this indicates a
5217 // `issue_52891::{self}` case.
5218 err.span_suggestion(directive.use_span_with_attributes, message, String::new(),
5219 Applicability::MaybeIncorrect);
5225 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5228 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5229 -> Option<&'a NameBinding<'a>> {
5230 if ident.is_path_segment_keyword() {
5231 // Make sure `self`, `super` etc produce an error when passed to here.
5234 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5235 if let Some(binding) = entry.extern_crate_item {
5236 if !speculative && entry.introduced_by_item {
5237 self.record_use(ident, TypeNS, binding, false);
5241 let crate_id = if !speculative {
5242 self.crate_loader.process_path_extern(ident.name, ident.span)
5243 } else if let Some(crate_id) =
5244 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5249 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5250 self.populate_module_if_necessary(&crate_root);
5251 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5252 .to_name_binding(self.arenas))
5258 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5259 namespace == TypeNS && path.len() == 1 && path[0].ident.name == kw::SelfUpper
5262 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5263 namespace == ValueNS && path.len() == 1 && path[0].ident.name == kw::SelfLower
5266 fn names_to_string(idents: &[Ident]) -> String {
5267 let mut result = String::new();
5268 for (i, ident) in idents.iter()
5269 .filter(|ident| ident.name != kw::PathRoot)
5272 result.push_str("::");
5274 result.push_str(&ident.as_str());
5279 fn path_names_to_string(path: &Path) -> String {
5280 names_to_string(&path.segments.iter()
5281 .map(|seg| seg.ident)
5282 .collect::<Vec<_>>())
5285 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5286 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5287 let variant_path = &suggestion.path;
5288 let variant_path_string = path_names_to_string(variant_path);
5290 let path_len = suggestion.path.segments.len();
5291 let enum_path = ast::Path {
5292 span: suggestion.path.span,
5293 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5295 let enum_path_string = path_names_to_string(&enum_path);
5297 (variant_path_string, enum_path_string)
5300 /// When an entity with a given name is not available in scope, we search for
5301 /// entities with that name in all crates. This method allows outputting the
5302 /// results of this search in a programmer-friendly way
5303 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5304 // This is `None` if all placement locations are inside expansions
5306 candidates: &[ImportSuggestion],
5310 // we want consistent results across executions, but candidates are produced
5311 // by iterating through a hash map, so make sure they are ordered:
5312 let mut path_strings: Vec<_> =
5313 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5314 path_strings.sort();
5316 let better = if better { "better " } else { "" };
5317 let msg_diff = match path_strings.len() {
5318 1 => " is found in another module, you can import it",
5319 _ => "s are found in other modules, you can import them",
5321 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5323 if let Some(span) = span {
5324 for candidate in &mut path_strings {
5325 // produce an additional newline to separate the new use statement
5326 // from the directly following item.
5327 let additional_newline = if found_use {
5332 *candidate = format!("use {};\n{}", candidate, additional_newline);
5335 err.span_suggestions(
5338 path_strings.into_iter(),
5339 Applicability::Unspecified,
5344 for candidate in path_strings {
5346 msg.push_str(&candidate);
5351 /// A somewhat inefficient routine to obtain the name of a module.
5352 fn module_to_string(module: Module<'_>) -> Option<String> {
5353 let mut names = Vec::new();
5355 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5356 if let ModuleKind::Def(.., name) = module.kind {
5357 if let Some(parent) = module.parent {
5358 names.push(Ident::with_empty_ctxt(name));
5359 collect_mod(names, parent);
5362 // danger, shouldn't be ident?
5363 names.push(Ident::from_str("<opaque>"));
5364 collect_mod(names, module.parent.unwrap());
5367 collect_mod(&mut names, module);
5369 if names.is_empty() {
5372 Some(names_to_string(&names.into_iter()
5374 .collect::<Vec<_>>()))
5377 #[derive(Copy, Clone, Debug)]
5379 /// Do not issue the lint.
5382 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5383 /// In this case, we can take the span of that path.
5386 /// This lint comes from a `use` statement. In this case, what we
5387 /// care about really is the *root* `use` statement; e.g., if we
5388 /// have nested things like `use a::{b, c}`, we care about the
5390 UsePath { root_id: NodeId, root_span: Span },
5392 /// This is the "trait item" from a fully qualified path. For example,
5393 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5394 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5395 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5399 fn node_id(&self) -> Option<NodeId> {
5401 CrateLint::No => None,
5402 CrateLint::SimplePath(id) |
5403 CrateLint::UsePath { root_id: id, .. } |
5404 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5409 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }