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::{Upvar, UpvarMap, 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, _)
616 | Res::Def(DefKind::Fn, _)
617 | Res::Def(DefKind::Method, _)
618 | Res::Def(DefKind::AssocConst, _)
620 | Res::Def(DefKind::ConstParam, _) => true,
623 PathSource::Pat => match res {
624 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
625 Res::Def(DefKind::Const, _) | Res::Def(DefKind::AssocConst, _) |
626 Res::SelfCtor(..) => true,
629 PathSource::TupleStruct => match res {
630 Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..) => true,
633 PathSource::Struct => match res {
634 Res::Def(DefKind::Struct, _)
635 | Res::Def(DefKind::Union, _)
636 | Res::Def(DefKind::Variant, _)
637 | Res::Def(DefKind::TyAlias, _)
638 | Res::Def(DefKind::AssocTy, _)
639 | Res::SelfTy(..) => true,
642 PathSource::TraitItem(ns) => match res {
643 Res::Def(DefKind::AssocConst, _)
644 | Res::Def(DefKind::Method, _) if ns == ValueNS => true,
645 Res::Def(DefKind::AssocTy, _) if ns == TypeNS => true,
648 PathSource::Visibility => match res {
649 Res::Def(DefKind::Mod, _) => true,
655 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
656 __diagnostic_used!(E0404);
657 __diagnostic_used!(E0405);
658 __diagnostic_used!(E0412);
659 __diagnostic_used!(E0422);
660 __diagnostic_used!(E0423);
661 __diagnostic_used!(E0425);
662 __diagnostic_used!(E0531);
663 __diagnostic_used!(E0532);
664 __diagnostic_used!(E0573);
665 __diagnostic_used!(E0574);
666 __diagnostic_used!(E0575);
667 __diagnostic_used!(E0576);
668 __diagnostic_used!(E0577);
669 __diagnostic_used!(E0578);
670 match (self, has_unexpected_resolution) {
671 (PathSource::Trait(_), true) => "E0404",
672 (PathSource::Trait(_), false) => "E0405",
673 (PathSource::Type, true) => "E0573",
674 (PathSource::Type, false) => "E0412",
675 (PathSource::Struct, true) => "E0574",
676 (PathSource::Struct, false) => "E0422",
677 (PathSource::Expr(..), true) => "E0423",
678 (PathSource::Expr(..), false) => "E0425",
679 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
680 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
681 (PathSource::TraitItem(..), true) => "E0575",
682 (PathSource::TraitItem(..), false) => "E0576",
683 (PathSource::Visibility, true) => "E0577",
684 (PathSource::Visibility, false) => "E0578",
689 // A minimal representation of a path segment. We use this in resolve because
690 // we synthesize 'path segments' which don't have the rest of an AST or HIR
692 #[derive(Clone, Copy, Debug)]
699 fn from_path(path: &Path) -> Vec<Segment> {
700 path.segments.iter().map(|s| s.into()).collect()
703 fn from_ident(ident: Ident) -> Segment {
710 fn names_to_string(segments: &[Segment]) -> String {
711 names_to_string(&segments.iter()
712 .map(|seg| seg.ident)
713 .collect::<Vec<_>>())
717 impl<'a> From<&'a ast::PathSegment> for Segment {
718 fn from(seg: &'a ast::PathSegment) -> Segment {
726 struct UsePlacementFinder {
727 target_module: NodeId,
732 impl UsePlacementFinder {
733 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
734 let mut finder = UsePlacementFinder {
739 visit::walk_crate(&mut finder, krate);
740 (finder.span, finder.found_use)
744 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
747 module: &'tcx ast::Mod,
749 _: &[ast::Attribute],
752 if self.span.is_some() {
755 if node_id != self.target_module {
756 visit::walk_mod(self, module);
759 // find a use statement
760 for item in &module.items {
762 ItemKind::Use(..) => {
763 // don't suggest placing a use before the prelude
764 // import or other generated ones
765 if item.span.ctxt().outer_expn_info().is_none() {
766 self.span = Some(item.span.shrink_to_lo());
767 self.found_use = true;
771 // don't place use before extern crate
772 ItemKind::ExternCrate(_) => {}
773 // but place them before the first other item
774 _ => if self.span.map_or(true, |span| item.span < span ) {
775 if item.span.ctxt().outer_expn_info().is_none() {
776 // don't insert between attributes and an item
777 if item.attrs.is_empty() {
778 self.span = Some(item.span.shrink_to_lo());
780 // find the first attribute on the item
781 for attr in &item.attrs {
782 if self.span.map_or(true, |span| attr.span < span) {
783 self.span = Some(attr.span.shrink_to_lo());
794 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
795 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
796 fn visit_item(&mut self, item: &'tcx Item) {
797 self.resolve_item(item);
799 fn visit_arm(&mut self, arm: &'tcx Arm) {
800 self.resolve_arm(arm);
802 fn visit_block(&mut self, block: &'tcx Block) {
803 self.resolve_block(block);
805 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
806 debug!("visit_anon_const {:?}", constant);
807 self.with_constant_rib(|this| {
808 visit::walk_anon_const(this, constant);
811 fn visit_expr(&mut self, expr: &'tcx Expr) {
812 self.resolve_expr(expr, None);
814 fn visit_local(&mut self, local: &'tcx Local) {
815 self.resolve_local(local);
817 fn visit_ty(&mut self, ty: &'tcx Ty) {
819 TyKind::Path(ref qself, ref path) => {
820 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
822 TyKind::ImplicitSelf => {
823 let self_ty = Ident::with_empty_ctxt(kw::SelfUpper);
824 let res = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
825 .map_or(Res::Err, |d| d.res());
826 self.record_partial_res(ty.id, PartialRes::new(res));
830 visit::walk_ty(self, ty);
832 fn visit_poly_trait_ref(&mut self,
833 tref: &'tcx ast::PolyTraitRef,
834 m: &'tcx ast::TraitBoundModifier) {
835 self.smart_resolve_path(tref.trait_ref.ref_id, None,
836 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
837 visit::walk_poly_trait_ref(self, tref, m);
839 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
840 let generic_params = match foreign_item.node {
841 ForeignItemKind::Fn(_, ref generics) => {
842 HasGenericParams(generics, ItemRibKind)
844 ForeignItemKind::Static(..) => NoGenericParams,
845 ForeignItemKind::Ty => NoGenericParams,
846 ForeignItemKind::Macro(..) => NoGenericParams,
848 self.with_generic_param_rib(generic_params, |this| {
849 visit::walk_foreign_item(this, foreign_item);
852 fn visit_fn(&mut self,
853 function_kind: FnKind<'tcx>,
854 declaration: &'tcx FnDecl,
858 debug!("(resolving function) entering function");
859 let (rib_kind, asyncness) = match function_kind {
860 FnKind::ItemFn(_, ref header, ..) =>
861 (FnItemRibKind, &header.asyncness.node),
862 FnKind::Method(_, ref sig, _, _) =>
863 (AssocItemRibKind, &sig.header.asyncness.node),
864 FnKind::Closure(_) =>
865 // Async closures aren't resolved through `visit_fn`-- they're
866 // processed separately
867 (ClosureRibKind(node_id), &IsAsync::NotAsync),
870 // Create a value rib for the function.
871 self.ribs[ValueNS].push(Rib::new(rib_kind));
873 // Create a label rib for the function.
874 self.label_ribs.push(Rib::new(rib_kind));
876 // Add each argument to the rib.
877 let mut bindings_list = FxHashMap::default();
878 let mut add_argument = |argument: &ast::Arg| {
879 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
880 self.visit_ty(&argument.ty);
881 debug!("(resolving function) recorded argument");
884 // Walk the generated async arguments if this is an `async fn`, otherwise walk the
886 if let IsAsync::Async { ref arguments, .. } = asyncness {
887 for (i, a) in arguments.iter().enumerate() {
888 if let Some(arg) = &a.arg {
891 add_argument(&declaration.inputs[i]);
895 for a in &declaration.inputs { add_argument(a); }
898 visit::walk_fn_ret_ty(self, &declaration.output);
900 // Resolve the function body, potentially inside the body of an async closure
901 if let IsAsync::Async { closure_id, .. } = asyncness {
902 let rib_kind = ClosureRibKind(*closure_id);
903 self.ribs[ValueNS].push(Rib::new(rib_kind));
904 self.label_ribs.push(Rib::new(rib_kind));
907 match function_kind {
908 FnKind::ItemFn(.., body) | FnKind::Method(.., body) => {
909 if let IsAsync::Async { ref arguments, .. } = asyncness {
910 let mut body = body.clone();
911 // Insert the generated statements into the body before attempting to
913 for a in arguments.iter().rev() {
914 if let Some(pat_stmt) = a.pat_stmt.clone() {
915 body.stmts.insert(0, pat_stmt);
917 body.stmts.insert(0, a.move_stmt.clone());
919 self.visit_block(&body);
921 self.visit_block(body);
924 FnKind::Closure(body) => {
925 self.visit_expr(body);
929 // Leave the body of the async closure
930 if asyncness.is_async() {
931 self.label_ribs.pop();
932 self.ribs[ValueNS].pop();
935 debug!("(resolving function) leaving function");
937 self.label_ribs.pop();
938 self.ribs[ValueNS].pop();
941 fn visit_generics(&mut self, generics: &'tcx Generics) {
942 // For type parameter defaults, we have to ban access
943 // to following type parameters, as the InternalSubsts can only
944 // provide previous type parameters as they're built. We
945 // put all the parameters on the ban list and then remove
946 // them one by one as they are processed and become available.
947 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
948 let mut found_default = false;
949 default_ban_rib.bindings.extend(generics.params.iter()
950 .filter_map(|param| match param.kind {
951 GenericParamKind::Const { .. } |
952 GenericParamKind::Lifetime { .. } => None,
953 GenericParamKind::Type { ref default, .. } => {
954 found_default |= default.is_some();
956 Some((Ident::with_empty_ctxt(param.ident.name), Res::Err))
963 // We also ban access to type parameters for use as the types of const parameters.
964 let mut const_ty_param_ban_rib = Rib::new(TyParamAsConstParamTy);
965 const_ty_param_ban_rib.bindings.extend(generics.params.iter()
967 if let GenericParamKind::Type { .. } = param.kind {
973 .map(|param| (Ident::with_empty_ctxt(param.ident.name), Res::Err)));
975 for param in &generics.params {
977 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
978 GenericParamKind::Type { ref default, .. } => {
979 for bound in ¶m.bounds {
980 self.visit_param_bound(bound);
983 if let Some(ref ty) = default {
984 self.ribs[TypeNS].push(default_ban_rib);
986 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
989 // Allow all following defaults to refer to this type parameter.
990 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
992 GenericParamKind::Const { ref ty } => {
993 self.ribs[TypeNS].push(const_ty_param_ban_rib);
995 for bound in ¶m.bounds {
996 self.visit_param_bound(bound);
1001 const_ty_param_ban_rib = self.ribs[TypeNS].pop().unwrap();
1005 for p in &generics.where_clause.predicates {
1006 self.visit_where_predicate(p);
1011 #[derive(Copy, Clone)]
1012 enum GenericParameters<'a, 'b> {
1014 HasGenericParams(// Type parameters.
1017 // The kind of the rib used for type parameters.
1021 /// The rib kind controls the translation of local
1022 /// definitions (`Res::Local`) to upvars (`Res::Upvar`).
1023 #[derive(Copy, Clone, Debug)]
1025 /// No translation needs to be applied.
1028 /// We passed through a closure scope at the given `NodeId`.
1029 /// Translate upvars as appropriate.
1030 ClosureRibKind(NodeId /* func id */),
1032 /// We passed through an impl or trait and are now in one of its
1033 /// methods or associated types. Allow references to ty params that impl or trait
1034 /// binds. Disallow any other upvars (including other ty params that are
1038 /// We passed through a function definition. Disallow upvars.
1039 /// Permit only those const parameters that are specified in the function's generics.
1042 /// We passed through an item scope. Disallow upvars.
1045 /// We're in a constant item. Can't refer to dynamic stuff.
1046 ConstantItemRibKind,
1048 /// We passed through a module.
1049 ModuleRibKind(Module<'a>),
1051 /// We passed through a `macro_rules!` statement
1052 MacroDefinition(DefId),
1054 /// All bindings in this rib are type parameters that can't be used
1055 /// from the default of a type parameter because they're not declared
1056 /// before said type parameter. Also see the `visit_generics` override.
1057 ForwardTyParamBanRibKind,
1059 /// We forbid the use of type parameters as the types of const parameters.
1060 TyParamAsConstParamTy,
1063 /// A single local scope.
1065 /// A rib represents a scope names can live in. Note that these appear in many places, not just
1066 /// around braces. At any place where the list of accessible names (of the given namespace)
1067 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
1068 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
1071 /// Different [rib kinds](enum.RibKind) are transparent for different names.
1073 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
1074 /// resolving, the name is looked up from inside out.
1076 struct Rib<'a, R = Res> {
1077 bindings: FxHashMap<Ident, R>,
1081 impl<'a, R> Rib<'a, R> {
1082 fn new(kind: RibKind<'a>) -> Rib<'a, R> {
1084 bindings: Default::default(),
1090 /// An intermediate resolution result.
1092 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
1093 /// items are visible in their whole block, while `Res`es only from the place they are defined
1095 enum LexicalScopeBinding<'a> {
1096 Item(&'a NameBinding<'a>),
1100 impl<'a> LexicalScopeBinding<'a> {
1101 fn item(self) -> Option<&'a NameBinding<'a>> {
1103 LexicalScopeBinding::Item(binding) => Some(binding),
1108 fn res(self) -> Res {
1110 LexicalScopeBinding::Item(binding) => binding.res(),
1111 LexicalScopeBinding::Res(res) => res,
1116 #[derive(Copy, Clone, Debug)]
1117 enum ModuleOrUniformRoot<'a> {
1121 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1122 CrateRootAndExternPrelude,
1124 /// Virtual module that denotes resolution in extern prelude.
1125 /// Used for paths starting with `::` on 2018 edition.
1128 /// Virtual module that denotes resolution in current scope.
1129 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1130 /// are always split into two parts, the first of which should be some kind of module.
1134 impl ModuleOrUniformRoot<'_> {
1135 fn same_def(lhs: Self, rhs: Self) -> bool {
1137 (ModuleOrUniformRoot::Module(lhs),
1138 ModuleOrUniformRoot::Module(rhs)) => lhs.def_id() == rhs.def_id(),
1139 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1140 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1141 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1142 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1148 #[derive(Clone, Debug)]
1149 enum PathResult<'a> {
1150 Module(ModuleOrUniformRoot<'a>),
1151 NonModule(PartialRes),
1156 suggestion: Option<Suggestion>,
1157 is_error_from_last_segment: bool,
1162 /// An anonymous module; e.g., just a block.
1166 /// fn f() {} // (1)
1167 /// { // This is an anonymous module
1168 /// f(); // This resolves to (2) as we are inside the block.
1169 /// fn f() {} // (2)
1171 /// f(); // Resolves to (1)
1175 /// Any module with a name.
1179 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1180 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1182 Def(DefKind, DefId, Name),
1186 /// Get name of the module.
1187 pub fn name(&self) -> Option<Name> {
1189 ModuleKind::Block(..) => None,
1190 ModuleKind::Def(.., name) => Some(*name),
1195 /// One node in the tree of modules.
1196 pub struct ModuleData<'a> {
1197 parent: Option<Module<'a>>,
1200 // The def id of the closest normal module (`mod`) ancestor (including this module).
1201 normal_ancestor_id: DefId,
1203 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1204 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1205 Option<&'a NameBinding<'a>>)>>,
1206 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1208 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1210 // Macro invocations that can expand into items in this module.
1211 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1213 no_implicit_prelude: bool,
1215 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1216 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1218 // Used to memoize the traits in this module for faster searches through all traits in scope.
1219 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1221 // Whether this module is populated. If not populated, any attempt to
1222 // access the children must be preceded with a
1223 // `populate_module_if_necessary` call.
1224 populated: Cell<bool>,
1226 /// Span of the module itself. Used for error reporting.
1232 type Module<'a> = &'a ModuleData<'a>;
1234 impl<'a> ModuleData<'a> {
1235 fn new(parent: Option<Module<'a>>,
1237 normal_ancestor_id: DefId,
1239 span: Span) -> Self {
1244 resolutions: Default::default(),
1245 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1246 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1247 builtin_attrs: RefCell::new(Vec::new()),
1248 unresolved_invocations: Default::default(),
1249 no_implicit_prelude: false,
1250 glob_importers: RefCell::new(Vec::new()),
1251 globs: RefCell::new(Vec::new()),
1252 traits: RefCell::new(None),
1253 populated: Cell::new(normal_ancestor_id.is_local()),
1259 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1260 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1261 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1265 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1266 let resolutions = self.resolutions.borrow();
1267 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1268 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1269 for &(&(ident, ns), &resolution) in resolutions.iter() {
1270 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1274 fn res(&self) -> Option<Res> {
1276 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
1281 fn def_kind(&self) -> Option<DefKind> {
1283 ModuleKind::Def(kind, ..) => Some(kind),
1288 fn def_id(&self) -> Option<DefId> {
1290 ModuleKind::Def(_, def_id, _) => Some(def_id),
1295 // `self` resolves to the first module ancestor that `is_normal`.
1296 fn is_normal(&self) -> bool {
1298 ModuleKind::Def(DefKind::Mod, _, _) => true,
1303 fn is_trait(&self) -> bool {
1305 ModuleKind::Def(DefKind::Trait, _, _) => true,
1310 fn nearest_item_scope(&'a self) -> Module<'a> {
1311 if self.is_trait() { self.parent.unwrap() } else { self }
1314 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1315 while !ptr::eq(self, other) {
1316 if let Some(parent) = other.parent {
1326 impl<'a> fmt::Debug for ModuleData<'a> {
1327 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1328 write!(f, "{:?}", self.res())
1332 /// Records a possibly-private value, type, or module definition.
1333 #[derive(Clone, Debug)]
1334 pub struct NameBinding<'a> {
1335 kind: NameBindingKind<'a>,
1336 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1339 vis: ty::Visibility,
1342 pub trait ToNameBinding<'a> {
1343 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1346 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1347 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1352 #[derive(Clone, Debug)]
1353 enum NameBindingKind<'a> {
1354 Res(Res, /* is_macro_export */ bool),
1357 binding: &'a NameBinding<'a>,
1358 directive: &'a ImportDirective<'a>,
1363 impl<'a> NameBindingKind<'a> {
1364 /// Is this a name binding of a import?
1365 fn is_import(&self) -> bool {
1367 NameBindingKind::Import { .. } => true,
1373 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1375 struct UseError<'a> {
1376 err: DiagnosticBuilder<'a>,
1377 /// Attach `use` statements for these candidates.
1378 candidates: Vec<ImportSuggestion>,
1379 /// The `NodeId` of the module to place the use-statements in.
1381 /// Whether the diagnostic should state that it's "better".
1385 #[derive(Clone, Copy, PartialEq, Debug)]
1386 enum AmbiguityKind {
1390 LegacyHelperVsPrelude,
1395 MoreExpandedVsOuter,
1398 impl AmbiguityKind {
1399 fn descr(self) -> &'static str {
1401 AmbiguityKind::Import =>
1402 "name vs any other name during import resolution",
1403 AmbiguityKind::BuiltinAttr =>
1404 "built-in attribute vs any other name",
1405 AmbiguityKind::DeriveHelper =>
1406 "derive helper attribute vs any other name",
1407 AmbiguityKind::LegacyHelperVsPrelude =>
1408 "legacy plugin helper attribute vs name from prelude",
1409 AmbiguityKind::LegacyVsModern =>
1410 "`macro_rules` vs non-`macro_rules` from other module",
1411 AmbiguityKind::GlobVsOuter =>
1412 "glob import vs any other name from outer scope during import/macro resolution",
1413 AmbiguityKind::GlobVsGlob =>
1414 "glob import vs glob import in the same module",
1415 AmbiguityKind::GlobVsExpanded =>
1416 "glob import vs macro-expanded name in the same \
1417 module during import/macro resolution",
1418 AmbiguityKind::MoreExpandedVsOuter =>
1419 "macro-expanded name vs less macro-expanded name \
1420 from outer scope during import/macro resolution",
1425 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1426 #[derive(Clone, Copy, PartialEq)]
1427 enum AmbiguityErrorMisc {
1434 struct AmbiguityError<'a> {
1435 kind: AmbiguityKind,
1437 b1: &'a NameBinding<'a>,
1438 b2: &'a NameBinding<'a>,
1439 misc1: AmbiguityErrorMisc,
1440 misc2: AmbiguityErrorMisc,
1443 impl<'a> NameBinding<'a> {
1444 fn module(&self) -> Option<Module<'a>> {
1446 NameBindingKind::Module(module) => Some(module),
1447 NameBindingKind::Import { binding, .. } => binding.module(),
1452 fn res(&self) -> Res {
1454 NameBindingKind::Res(res, _) => res,
1455 NameBindingKind::Module(module) => module.res().unwrap(),
1456 NameBindingKind::Import { binding, .. } => binding.res(),
1460 fn is_ambiguity(&self) -> bool {
1461 self.ambiguity.is_some() || match self.kind {
1462 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1467 // We sometimes need to treat variants as `pub` for backwards compatibility.
1468 fn pseudo_vis(&self) -> ty::Visibility {
1469 if self.is_variant() && self.res().def_id().is_local() {
1470 ty::Visibility::Public
1476 fn is_variant(&self) -> bool {
1478 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _) |
1479 NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
1484 fn is_extern_crate(&self) -> bool {
1486 NameBindingKind::Import {
1487 directive: &ImportDirective {
1488 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1491 NameBindingKind::Module(
1492 &ModuleData { kind: ModuleKind::Def(DefKind::Mod, def_id, _), .. }
1493 ) => def_id.index == CRATE_DEF_INDEX,
1498 fn is_import(&self) -> bool {
1500 NameBindingKind::Import { .. } => true,
1505 fn is_glob_import(&self) -> bool {
1507 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1512 fn is_importable(&self) -> bool {
1514 Res::Def(DefKind::AssocConst, _)
1515 | Res::Def(DefKind::Method, _)
1516 | Res::Def(DefKind::AssocTy, _) => false,
1521 fn is_macro_def(&self) -> bool {
1523 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
1528 fn macro_kind(&self) -> Option<MacroKind> {
1530 Res::Def(DefKind::Macro(kind), _) => Some(kind),
1531 Res::NonMacroAttr(..) => Some(MacroKind::Attr),
1536 fn descr(&self) -> &'static str {
1537 if self.is_extern_crate() { "extern crate" } else { self.res().descr() }
1540 fn article(&self) -> &'static str {
1541 if self.is_extern_crate() { "an" } else { self.res().article() }
1544 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1545 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1546 // Then this function returns `true` if `self` may emerge from a macro *after* that
1547 // in some later round and screw up our previously found resolution.
1548 // See more detailed explanation in
1549 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1550 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1551 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1552 // Expansions are partially ordered, so "may appear after" is an inversion of
1553 // "certainly appears before or simultaneously" and includes unordered cases.
1554 let self_parent_expansion = self.expansion;
1555 let other_parent_expansion = binding.expansion;
1556 let certainly_before_other_or_simultaneously =
1557 other_parent_expansion.is_descendant_of(self_parent_expansion);
1558 let certainly_before_invoc_or_simultaneously =
1559 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1560 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1564 /// Interns the names of the primitive types.
1566 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1567 /// special handling, since they have no place of origin.
1569 struct PrimitiveTypeTable {
1570 primitive_types: FxHashMap<Name, PrimTy>,
1573 impl PrimitiveTypeTable {
1574 fn new() -> PrimitiveTypeTable {
1575 let mut table = PrimitiveTypeTable::default();
1577 table.intern("bool", Bool);
1578 table.intern("char", Char);
1579 table.intern("f32", Float(FloatTy::F32));
1580 table.intern("f64", Float(FloatTy::F64));
1581 table.intern("isize", Int(IntTy::Isize));
1582 table.intern("i8", Int(IntTy::I8));
1583 table.intern("i16", Int(IntTy::I16));
1584 table.intern("i32", Int(IntTy::I32));
1585 table.intern("i64", Int(IntTy::I64));
1586 table.intern("i128", Int(IntTy::I128));
1587 table.intern("str", Str);
1588 table.intern("usize", Uint(UintTy::Usize));
1589 table.intern("u8", Uint(UintTy::U8));
1590 table.intern("u16", Uint(UintTy::U16));
1591 table.intern("u32", Uint(UintTy::U32));
1592 table.intern("u64", Uint(UintTy::U64));
1593 table.intern("u128", Uint(UintTy::U128));
1597 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1598 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1602 #[derive(Debug, Default, Clone)]
1603 pub struct ExternPreludeEntry<'a> {
1604 extern_crate_item: Option<&'a NameBinding<'a>>,
1605 pub introduced_by_item: bool,
1608 /// The main resolver class.
1610 /// This is the visitor that walks the whole crate.
1611 pub struct Resolver<'a> {
1612 session: &'a Session,
1615 pub definitions: Definitions,
1617 graph_root: Module<'a>,
1619 prelude: Option<Module<'a>>,
1620 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1622 /// N.B., this is used only for better diagnostics, not name resolution itself.
1623 has_self: FxHashSet<DefId>,
1625 /// Names of fields of an item `DefId` accessible with dot syntax.
1626 /// Used for hints during error reporting.
1627 field_names: FxHashMap<DefId, Vec<Name>>,
1629 /// All imports known to succeed or fail.
1630 determined_imports: Vec<&'a ImportDirective<'a>>,
1632 /// All non-determined imports.
1633 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1635 /// The module that represents the current item scope.
1636 current_module: Module<'a>,
1638 /// The current set of local scopes for types and values.
1639 /// FIXME #4948: Reuse ribs to avoid allocation.
1640 ribs: PerNS<Vec<Rib<'a>>>,
1642 /// The current set of local scopes, for labels.
1643 label_ribs: Vec<Rib<'a, NodeId>>,
1645 /// The trait that the current context can refer to.
1646 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1648 /// The current self type if inside an impl (used for better errors).
1649 current_self_type: Option<Ty>,
1651 /// The current self item if inside an ADT (used for better errors).
1652 current_self_item: Option<NodeId>,
1654 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1655 /// We are resolving a last import segment during import validation.
1656 last_import_segment: bool,
1657 /// This binding should be ignored during in-module resolution, so that we don't get
1658 /// "self-confirming" import resolutions during import validation.
1659 blacklisted_binding: Option<&'a NameBinding<'a>>,
1661 /// The idents for the primitive types.
1662 primitive_type_table: PrimitiveTypeTable,
1664 /// Resolutions for nodes that have a single resolution.
1665 partial_res_map: NodeMap<PartialRes>,
1666 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
1667 import_res_map: NodeMap<PerNS<Option<Res>>>,
1668 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
1669 label_res_map: NodeMap<NodeId>,
1671 pub upvars: UpvarMap,
1672 pub export_map: ExportMap<NodeId>,
1673 pub trait_map: TraitMap,
1675 /// A map from nodes to anonymous modules.
1676 /// Anonymous modules are pseudo-modules that are implicitly created around items
1677 /// contained within blocks.
1679 /// For example, if we have this:
1687 /// There will be an anonymous module created around `g` with the ID of the
1688 /// entry block for `f`.
1689 block_map: NodeMap<Module<'a>>,
1690 module_map: FxHashMap<DefId, Module<'a>>,
1691 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1692 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1694 /// Maps glob imports to the names of items actually imported.
1695 pub glob_map: GlobMap,
1697 used_imports: FxHashSet<(NodeId, Namespace)>,
1698 pub maybe_unused_trait_imports: NodeSet,
1699 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1701 /// A list of labels as of yet unused. Labels will be removed from this map when
1702 /// they are used (in a `break` or `continue` statement)
1703 pub unused_labels: FxHashMap<NodeId, Span>,
1705 /// Privacy errors are delayed until the end in order to deduplicate them.
1706 privacy_errors: Vec<PrivacyError<'a>>,
1707 /// Ambiguity errors are delayed for deduplication.
1708 ambiguity_errors: Vec<AmbiguityError<'a>>,
1709 /// `use` injections are delayed for better placement and deduplication.
1710 use_injections: Vec<UseError<'a>>,
1711 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1712 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1714 arenas: &'a ResolverArenas<'a>,
1715 dummy_binding: &'a NameBinding<'a>,
1717 crate_loader: &'a mut CrateLoader<'a>,
1718 macro_names: FxHashSet<Ident>,
1719 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1720 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1721 pub all_macros: FxHashMap<Name, Res>,
1722 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1723 macro_defs: FxHashMap<Mark, DefId>,
1724 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1726 /// List of crate local macros that we need to warn about as being unused.
1727 /// Right now this only includes macro_rules! macros, and macros 2.0.
1728 unused_macros: FxHashSet<DefId>,
1730 /// Maps the `Mark` of an expansion to its containing module or block.
1731 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1733 /// Avoid duplicated errors for "name already defined".
1734 name_already_seen: FxHashMap<Name, Span>,
1736 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1738 /// Table for mapping struct IDs into struct constructor IDs,
1739 /// it's not used during normal resolution, only for better error reporting.
1740 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
1742 /// Only used for better errors on `fn(): fn()`.
1743 current_type_ascription: Vec<Span>,
1745 injected_crate: Option<Module<'a>>,
1748 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1750 pub struct ResolverArenas<'a> {
1751 modules: arena::TypedArena<ModuleData<'a>>,
1752 local_modules: RefCell<Vec<Module<'a>>>,
1753 name_bindings: arena::TypedArena<NameBinding<'a>>,
1754 import_directives: arena::TypedArena<ImportDirective<'a>>,
1755 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1756 invocation_data: arena::TypedArena<InvocationData<'a>>,
1757 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1760 impl<'a> ResolverArenas<'a> {
1761 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1762 let module = self.modules.alloc(module);
1763 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1764 self.local_modules.borrow_mut().push(module);
1768 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1769 self.local_modules.borrow()
1771 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1772 self.name_bindings.alloc(name_binding)
1774 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1775 -> &'a ImportDirective<'_> {
1776 self.import_directives.alloc(import_directive)
1778 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1779 self.name_resolutions.alloc(Default::default())
1781 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1782 -> &'a InvocationData<'a> {
1783 self.invocation_data.alloc(expansion_data)
1785 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1786 self.legacy_bindings.alloc(binding)
1790 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1791 fn parent(self, id: DefId) -> Option<DefId> {
1793 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1794 _ => self.cstore.def_key(id).parent,
1795 }.map(|index| DefId { index, ..id })
1799 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1800 /// the resolver is no longer needed as all the relevant information is inline.
1801 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1802 fn resolve_hir_path(
1807 self.resolve_hir_path_cb(path, is_value,
1808 |resolver, span, error| resolve_error(resolver, span, error))
1811 fn resolve_str_path(
1814 crate_root: Option<Symbol>,
1815 components: &[Symbol],
1818 let root = if crate_root.is_some() {
1823 let segments = iter::once(Ident::with_empty_ctxt(root))
1825 crate_root.into_iter()
1826 .chain(components.iter().cloned())
1827 .map(Ident::with_empty_ctxt)
1828 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1830 let path = ast::Path {
1835 self.resolve_hir_path(&path, is_value)
1838 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1839 self.partial_res_map.get(&id).cloned()
1842 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1843 self.import_res_map.get(&id).cloned().unwrap_or_default()
1846 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1847 self.label_res_map.get(&id).cloned()
1850 fn definitions(&mut self) -> &mut Definitions {
1851 &mut self.definitions
1855 impl<'a> Resolver<'a> {
1856 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1857 /// isn't something that can be returned because it can't be made to live that long,
1858 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1859 /// just that an error occurred.
1860 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1861 -> Result<hir::Path, ()> {
1862 let mut errored = false;
1864 let path = if path_str.starts_with("::") {
1867 segments: iter::once(Ident::with_empty_ctxt(kw::PathRoot))
1869 path_str.split("::").skip(1).map(Ident::from_str)
1871 .map(|i| self.new_ast_path_segment(i))
1879 .map(Ident::from_str)
1880 .map(|i| self.new_ast_path_segment(i))
1884 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1885 if errored || path.res == def::Res::Err {
1892 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1893 fn resolve_hir_path_cb<F>(
1899 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1901 let namespace = if is_value { ValueNS } else { TypeNS };
1902 let span = path.span;
1903 let segments = &path.segments;
1904 let path = Segment::from_path(&path);
1905 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1906 let res = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1907 span, CrateLint::No) {
1908 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1909 module.res().unwrap(),
1910 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1911 path_res.base_res(),
1912 PathResult::NonModule(..) => {
1913 error_callback(self, span, ResolutionError::FailedToResolve {
1914 label: String::from("type-relative paths are not supported in this context"),
1919 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1920 PathResult::Failed { span, label, suggestion, .. } => {
1921 error_callback(self, span, ResolutionError::FailedToResolve {
1929 let segments: Vec<_> = segments.iter().map(|seg| {
1930 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1931 hir_seg.res = Some(self.partial_res_map.get(&seg.id).map_or(def::Res::Err, |p| {
1932 p.base_res().map_id(|_| panic!("unexpected node_id"))
1938 res: res.map_id(|_| panic!("unexpected node_id")),
1939 segments: segments.into(),
1943 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1944 let mut seg = ast::PathSegment::from_ident(ident);
1945 seg.id = self.session.next_node_id();
1950 impl<'a> Resolver<'a> {
1951 pub fn new(session: &'a Session,
1955 crate_loader: &'a mut CrateLoader<'a>,
1956 arenas: &'a ResolverArenas<'a>)
1958 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1959 let root_module_kind = ModuleKind::Def(
1964 let graph_root = arenas.alloc_module(ModuleData {
1965 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1966 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1968 let mut module_map = FxHashMap::default();
1969 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1971 let mut definitions = Definitions::default();
1972 DefCollector::new(&mut definitions, Mark::root())
1973 .collect_root(crate_name, session.local_crate_disambiguator());
1975 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1976 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1979 if !attr::contains_name(&krate.attrs, sym::no_core) {
1980 extern_prelude.insert(Ident::with_empty_ctxt(sym::core), Default::default());
1981 if !attr::contains_name(&krate.attrs, sym::no_std) {
1982 extern_prelude.insert(Ident::with_empty_ctxt(sym::std), Default::default());
1983 if session.rust_2018() {
1984 extern_prelude.insert(Ident::with_empty_ctxt(sym::meta), Default::default());
1989 let mut invocations = FxHashMap::default();
1990 invocations.insert(Mark::root(),
1991 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1993 let mut macro_defs = FxHashMap::default();
1994 macro_defs.insert(Mark::root(), root_def_id);
2003 // The outermost module has def ID 0; this is not reflected in the
2009 has_self: FxHashSet::default(),
2010 field_names: FxHashMap::default(),
2012 determined_imports: Vec::new(),
2013 indeterminate_imports: Vec::new(),
2015 current_module: graph_root,
2017 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2018 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2019 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2021 label_ribs: Vec::new(),
2023 current_trait_ref: None,
2024 current_self_type: None,
2025 current_self_item: None,
2026 last_import_segment: false,
2027 blacklisted_binding: None,
2029 primitive_type_table: PrimitiveTypeTable::new(),
2031 partial_res_map: Default::default(),
2032 import_res_map: Default::default(),
2033 label_res_map: Default::default(),
2034 upvars: Default::default(),
2035 export_map: FxHashMap::default(),
2036 trait_map: Default::default(),
2038 block_map: Default::default(),
2039 extern_module_map: FxHashMap::default(),
2040 binding_parent_modules: FxHashMap::default(),
2042 glob_map: Default::default(),
2044 used_imports: FxHashSet::default(),
2045 maybe_unused_trait_imports: Default::default(),
2046 maybe_unused_extern_crates: Vec::new(),
2048 unused_labels: FxHashMap::default(),
2050 privacy_errors: Vec::new(),
2051 ambiguity_errors: Vec::new(),
2052 use_injections: Vec::new(),
2053 macro_expanded_macro_export_errors: BTreeSet::new(),
2056 dummy_binding: arenas.alloc_name_binding(NameBinding {
2057 kind: NameBindingKind::Res(Res::Err, false),
2059 expansion: Mark::root(),
2061 vis: ty::Visibility::Public,
2065 macro_names: FxHashSet::default(),
2066 builtin_macros: FxHashMap::default(),
2067 macro_use_prelude: FxHashMap::default(),
2068 all_macros: FxHashMap::default(),
2069 macro_map: FxHashMap::default(),
2072 local_macro_def_scopes: FxHashMap::default(),
2073 name_already_seen: FxHashMap::default(),
2074 potentially_unused_imports: Vec::new(),
2075 struct_constructors: Default::default(),
2076 unused_macros: FxHashSet::default(),
2077 current_type_ascription: Vec::new(),
2078 injected_crate: None,
2082 pub fn arenas() -> ResolverArenas<'a> {
2086 /// Runs the function on each namespace.
2087 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
2093 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
2095 match self.macro_defs.get(&ctxt.outer()) {
2096 Some(&def_id) => return def_id,
2097 None => ctxt.remove_mark(),
2102 /// Entry point to crate resolution.
2103 pub fn resolve_crate(&mut self, krate: &Crate) {
2104 ImportResolver { resolver: self }.finalize_imports();
2105 self.current_module = self.graph_root;
2106 self.finalize_current_module_macro_resolutions();
2108 visit::walk_crate(self, krate);
2110 check_unused::check_crate(self, krate);
2111 self.report_errors(krate);
2112 self.crate_loader.postprocess(krate);
2119 normal_ancestor_id: DefId,
2123 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
2124 self.arenas.alloc_module(module)
2127 fn record_use(&mut self, ident: Ident, ns: Namespace,
2128 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
2129 if let Some((b2, kind)) = used_binding.ambiguity {
2130 self.ambiguity_errors.push(AmbiguityError {
2131 kind, ident, b1: used_binding, b2,
2132 misc1: AmbiguityErrorMisc::None,
2133 misc2: AmbiguityErrorMisc::None,
2136 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
2137 // Avoid marking `extern crate` items that refer to a name from extern prelude,
2138 // but not introduce it, as used if they are accessed from lexical scope.
2139 if is_lexical_scope {
2140 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
2141 if let Some(crate_item) = entry.extern_crate_item {
2142 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2149 directive.used.set(true);
2150 self.used_imports.insert((directive.id, ns));
2151 self.add_to_glob_map(&directive, ident);
2152 self.record_use(ident, ns, binding, false);
2157 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2158 if directive.is_glob() {
2159 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2163 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2164 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2165 /// `ident` in the first scope that defines it (or None if no scopes define it).
2167 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2168 /// the items are defined in the block. For example,
2171 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2174 /// g(); // This resolves to the local variable `g` since it shadows the item.
2178 /// Invariant: This must only be called during main resolution, not during
2179 /// import resolution.
2180 fn resolve_ident_in_lexical_scope(&mut self,
2183 record_used_id: Option<NodeId>,
2185 -> Option<LexicalScopeBinding<'a>> {
2186 assert!(ns == TypeNS || ns == ValueNS);
2187 if ident.name == kw::Invalid {
2188 return Some(LexicalScopeBinding::Res(Res::Err));
2190 ident.span = if ident.name == kw::SelfUpper {
2191 // FIXME(jseyfried) improve `Self` hygiene
2192 ident.span.with_ctxt(SyntaxContext::empty())
2193 } else if ns == TypeNS {
2196 ident.span.modern_and_legacy()
2199 // Walk backwards up the ribs in scope.
2200 let record_used = record_used_id.is_some();
2201 let mut module = self.graph_root;
2202 for i in (0 .. self.ribs[ns].len()).rev() {
2203 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2204 if let Some(res) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2205 // The ident resolves to a type parameter or local variable.
2206 return Some(LexicalScopeBinding::Res(
2207 self.adjust_local_res(ns, i, res, record_used, path_span)
2211 module = match self.ribs[ns][i].kind {
2212 ModuleRibKind(module) => module,
2213 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2214 // If an invocation of this macro created `ident`, give up on `ident`
2215 // and switch to `ident`'s source from the macro definition.
2216 ident.span.remove_mark();
2222 let item = self.resolve_ident_in_module_unadjusted(
2223 ModuleOrUniformRoot::Module(module),
2229 if let Ok(binding) = item {
2230 // The ident resolves to an item.
2231 return Some(LexicalScopeBinding::Item(binding));
2235 ModuleKind::Block(..) => {}, // We can see through blocks
2240 ident.span = ident.span.modern();
2241 let mut poisoned = None;
2243 let opt_module = if let Some(node_id) = record_used_id {
2244 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2245 node_id, &mut poisoned)
2247 self.hygienic_lexical_parent(module, &mut ident.span)
2249 module = unwrap_or!(opt_module, break);
2250 let orig_current_module = self.current_module;
2251 self.current_module = module; // Lexical resolutions can never be a privacy error.
2252 let result = self.resolve_ident_in_module_unadjusted(
2253 ModuleOrUniformRoot::Module(module),
2259 self.current_module = orig_current_module;
2263 if let Some(node_id) = poisoned {
2264 self.session.buffer_lint_with_diagnostic(
2265 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2266 node_id, ident.span,
2267 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2268 lint::builtin::BuiltinLintDiagnostics::
2269 ProcMacroDeriveResolutionFallback(ident.span),
2272 return Some(LexicalScopeBinding::Item(binding))
2274 Err(Determined) => continue,
2275 Err(Undetermined) =>
2276 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2280 if !module.no_implicit_prelude {
2282 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2283 return Some(LexicalScopeBinding::Item(binding));
2286 if ns == TypeNS && is_known_tool(ident.name) {
2287 let binding = (Res::ToolMod, ty::Visibility::Public,
2288 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2289 return Some(LexicalScopeBinding::Item(binding));
2291 if let Some(prelude) = self.prelude {
2292 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2293 ModuleOrUniformRoot::Module(prelude),
2299 return Some(LexicalScopeBinding::Item(binding));
2307 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2308 -> Option<Module<'a>> {
2309 if !module.expansion.outer_is_descendant_of(span.ctxt()) {
2310 return Some(self.macro_def_scope(span.remove_mark()));
2313 if let ModuleKind::Block(..) = module.kind {
2314 return Some(module.parent.unwrap());
2320 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2321 span: &mut Span, node_id: NodeId,
2322 poisoned: &mut Option<NodeId>)
2323 -> Option<Module<'a>> {
2324 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2328 // We need to support the next case under a deprecation warning
2331 // ---- begin: this comes from a proc macro derive
2332 // mod implementation_details {
2333 // // Note that `MyStruct` is not in scope here.
2334 // impl SomeTrait for MyStruct { ... }
2338 // So we have to fall back to the module's parent during lexical resolution in this case.
2339 if let Some(parent) = module.parent {
2340 // Inner module is inside the macro, parent module is outside of the macro.
2341 if module.expansion != parent.expansion &&
2342 module.expansion.is_descendant_of(parent.expansion) {
2343 // The macro is a proc macro derive
2344 if module.expansion.looks_like_proc_macro_derive() {
2345 if parent.expansion.outer_is_descendant_of(span.ctxt()) {
2346 *poisoned = Some(node_id);
2347 return module.parent;
2356 fn resolve_ident_in_module(
2358 module: ModuleOrUniformRoot<'a>,
2361 parent_scope: Option<&ParentScope<'a>>,
2364 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2365 self.resolve_ident_in_module_ext(
2366 module, ident, ns, parent_scope, record_used, path_span
2367 ).map_err(|(determinacy, _)| determinacy)
2370 fn resolve_ident_in_module_ext(
2372 module: ModuleOrUniformRoot<'a>,
2375 parent_scope: Option<&ParentScope<'a>>,
2378 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2379 let orig_current_module = self.current_module;
2381 ModuleOrUniformRoot::Module(module) => {
2382 ident.span = ident.span.modern();
2383 if let Some(def) = ident.span.adjust(module.expansion) {
2384 self.current_module = self.macro_def_scope(def);
2387 ModuleOrUniformRoot::ExternPrelude => {
2388 ident.span = ident.span.modern();
2389 ident.span.adjust(Mark::root());
2391 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2392 ModuleOrUniformRoot::CurrentScope => {
2396 let result = self.resolve_ident_in_module_unadjusted_ext(
2397 module, ident, ns, parent_scope, false, record_used, path_span,
2399 self.current_module = orig_current_module;
2403 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2404 let mut ctxt = ident.span.ctxt();
2405 let mark = if ident.name == kw::DollarCrate {
2406 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2407 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2408 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2409 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2410 // definitions actually produced by `macro` and `macro` definitions produced by
2411 // `macro_rules!`, but at least such configurations are not stable yet.
2412 ctxt = ctxt.modern_and_legacy();
2413 let mut iter = ctxt.marks().into_iter().rev().peekable();
2414 let mut result = None;
2415 // Find the last modern mark from the end if it exists.
2416 while let Some(&(mark, transparency)) = iter.peek() {
2417 if transparency == Transparency::Opaque {
2418 result = Some(mark);
2424 // Then find the last legacy mark from the end if it exists.
2425 for (mark, transparency) in iter {
2426 if transparency == Transparency::SemiTransparent {
2427 result = Some(mark);
2434 ctxt = ctxt.modern();
2435 ctxt.adjust(Mark::root())
2437 let module = match mark {
2438 Some(def) => self.macro_def_scope(def),
2439 None => return self.graph_root,
2441 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2444 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2445 let mut module = self.get_module(module.normal_ancestor_id);
2446 while module.span.ctxt().modern() != *ctxt {
2447 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2448 module = self.get_module(parent.normal_ancestor_id);
2455 // We maintain a list of value ribs and type ribs.
2457 // Simultaneously, we keep track of the current position in the module
2458 // graph in the `current_module` pointer. When we go to resolve a name in
2459 // the value or type namespaces, we first look through all the ribs and
2460 // then query the module graph. When we resolve a name in the module
2461 // namespace, we can skip all the ribs (since nested modules are not
2462 // allowed within blocks in Rust) and jump straight to the current module
2465 // Named implementations are handled separately. When we find a method
2466 // call, we consult the module node to find all of the implementations in
2467 // scope. This information is lazily cached in the module node. We then
2468 // generate a fake "implementation scope" containing all the
2469 // implementations thus found, for compatibility with old resolve pass.
2471 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2472 where F: FnOnce(&mut Resolver<'_>) -> T
2474 let id = self.definitions.local_def_id(id);
2475 let module = self.module_map.get(&id).cloned(); // clones a reference
2476 if let Some(module) = module {
2477 // Move down in the graph.
2478 let orig_module = replace(&mut self.current_module, module);
2479 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2480 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2482 self.finalize_current_module_macro_resolutions();
2485 self.current_module = orig_module;
2486 self.ribs[ValueNS].pop();
2487 self.ribs[TypeNS].pop();
2494 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2495 /// is returned by the given predicate function
2497 /// Stops after meeting a closure.
2498 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2499 where P: Fn(&Rib<'_, NodeId>, Ident) -> Option<R>
2501 for rib in self.label_ribs.iter().rev() {
2504 // If an invocation of this macro created `ident`, give up on `ident`
2505 // and switch to `ident`'s source from the macro definition.
2506 MacroDefinition(def) => {
2507 if def == self.macro_def(ident.span.ctxt()) {
2508 ident.span.remove_mark();
2512 // Do not resolve labels across function boundary
2516 let r = pred(rib, ident);
2524 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2525 debug!("resolve_adt");
2526 self.with_current_self_item(item, |this| {
2527 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2528 let item_def_id = this.definitions.local_def_id(item.id);
2529 this.with_self_rib(Res::SelfTy(None, Some(item_def_id)), |this| {
2530 visit::walk_item(this, item);
2536 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2537 let segments = &use_tree.prefix.segments;
2538 if !segments.is_empty() {
2539 let ident = segments[0].ident;
2540 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2544 let nss = match use_tree.kind {
2545 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2548 let report_error = |this: &Self, ns| {
2549 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2550 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2554 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2555 Some(LexicalScopeBinding::Res(..)) => {
2556 report_error(self, ns);
2558 Some(LexicalScopeBinding::Item(binding)) => {
2559 let orig_blacklisted_binding =
2560 mem::replace(&mut self.blacklisted_binding, Some(binding));
2561 if let Some(LexicalScopeBinding::Res(..)) =
2562 self.resolve_ident_in_lexical_scope(ident, ns, None,
2563 use_tree.prefix.span) {
2564 report_error(self, ns);
2566 self.blacklisted_binding = orig_blacklisted_binding;
2571 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2572 for (use_tree, _) in use_trees {
2573 self.future_proof_import(use_tree);
2578 fn resolve_item(&mut self, item: &Item) {
2579 let name = item.ident.name;
2580 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2583 ItemKind::Ty(_, ref generics) |
2584 ItemKind::Fn(_, _, ref generics, _) |
2585 ItemKind::Existential(_, ref generics) => {
2586 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2587 |this| visit::walk_item(this, item));
2590 ItemKind::Enum(_, ref generics) |
2591 ItemKind::Struct(_, ref generics) |
2592 ItemKind::Union(_, ref generics) => {
2593 self.resolve_adt(item, generics);
2596 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2597 self.resolve_implementation(generics,
2603 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2604 // Create a new rib for the trait-wide type parameters.
2605 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2606 let local_def_id = this.definitions.local_def_id(item.id);
2607 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2608 this.visit_generics(generics);
2609 walk_list!(this, visit_param_bound, bounds);
2611 for trait_item in trait_items {
2612 let generic_params = HasGenericParams(&trait_item.generics,
2614 this.with_generic_param_rib(generic_params, |this| {
2615 match trait_item.node {
2616 TraitItemKind::Const(ref ty, ref default) => {
2619 // Only impose the restrictions of
2620 // ConstRibKind for an actual constant
2621 // expression in a provided default.
2622 if let Some(ref expr) = *default{
2623 this.with_constant_rib(|this| {
2624 this.visit_expr(expr);
2628 TraitItemKind::Method(_, _) => {
2629 visit::walk_trait_item(this, trait_item)
2631 TraitItemKind::Type(..) => {
2632 visit::walk_trait_item(this, trait_item)
2634 TraitItemKind::Macro(_) => {
2635 panic!("unexpanded macro in resolve!")
2644 ItemKind::TraitAlias(ref generics, ref bounds) => {
2645 // Create a new rib for the trait-wide type parameters.
2646 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2647 let local_def_id = this.definitions.local_def_id(item.id);
2648 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2649 this.visit_generics(generics);
2650 walk_list!(this, visit_param_bound, bounds);
2655 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2656 self.with_scope(item.id, |this| {
2657 visit::walk_item(this, item);
2661 ItemKind::Static(ref ty, _, ref expr) |
2662 ItemKind::Const(ref ty, ref expr) => {
2663 debug!("resolve_item ItemKind::Const");
2664 self.with_item_rib(|this| {
2666 this.with_constant_rib(|this| {
2667 this.visit_expr(expr);
2672 ItemKind::Use(ref use_tree) => {
2673 self.future_proof_import(use_tree);
2676 ItemKind::ExternCrate(..) |
2677 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2678 // do nothing, these are just around to be encoded
2681 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2685 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2686 where F: FnOnce(&mut Resolver<'_>)
2688 debug!("with_generic_param_rib");
2689 match generic_params {
2690 HasGenericParams(generics, rib_kind) => {
2691 let mut function_type_rib = Rib::new(rib_kind);
2692 let mut function_value_rib = Rib::new(rib_kind);
2693 let mut seen_bindings = FxHashMap::default();
2694 for param in &generics.params {
2696 GenericParamKind::Lifetime { .. } => {}
2697 GenericParamKind::Type { .. } => {
2698 let ident = param.ident.modern();
2699 debug!("with_generic_param_rib: {}", param.id);
2701 if seen_bindings.contains_key(&ident) {
2702 let span = seen_bindings.get(&ident).unwrap();
2703 let err = ResolutionError::NameAlreadyUsedInParameterList(
2707 resolve_error(self, param.ident.span, err);
2709 seen_bindings.entry(ident).or_insert(param.ident.span);
2711 // Plain insert (no renaming).
2714 self.definitions.local_def_id(param.id),
2716 function_type_rib.bindings.insert(ident, res);
2717 self.record_partial_res(param.id, PartialRes::new(res));
2719 GenericParamKind::Const { .. } => {
2720 let ident = param.ident.modern();
2721 debug!("with_generic_param_rib: {}", param.id);
2723 if seen_bindings.contains_key(&ident) {
2724 let span = seen_bindings.get(&ident).unwrap();
2725 let err = ResolutionError::NameAlreadyUsedInParameterList(
2729 resolve_error(self, param.ident.span, err);
2731 seen_bindings.entry(ident).or_insert(param.ident.span);
2734 DefKind::ConstParam,
2735 self.definitions.local_def_id(param.id),
2737 function_value_rib.bindings.insert(ident, res);
2738 self.record_partial_res(param.id, PartialRes::new(res));
2742 self.ribs[ValueNS].push(function_value_rib);
2743 self.ribs[TypeNS].push(function_type_rib);
2746 NoGenericParams => {
2753 if let HasGenericParams(..) = generic_params {
2754 self.ribs[TypeNS].pop();
2755 self.ribs[ValueNS].pop();
2759 fn with_label_rib<F>(&mut self, f: F)
2760 where F: FnOnce(&mut Resolver<'_>)
2762 self.label_ribs.push(Rib::new(NormalRibKind));
2764 self.label_ribs.pop();
2767 fn with_item_rib<F>(&mut self, f: F)
2768 where F: FnOnce(&mut Resolver<'_>)
2770 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2771 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2773 self.ribs[TypeNS].pop();
2774 self.ribs[ValueNS].pop();
2777 fn with_constant_rib<F>(&mut self, f: F)
2778 where F: FnOnce(&mut Resolver<'_>)
2780 debug!("with_constant_rib");
2781 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2782 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2784 self.label_ribs.pop();
2785 self.ribs[ValueNS].pop();
2788 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2789 where F: FnOnce(&mut Resolver<'_>) -> T
2791 // Handle nested impls (inside fn bodies)
2792 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2793 let result = f(self);
2794 self.current_self_type = previous_value;
2798 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2799 where F: FnOnce(&mut Resolver<'_>) -> T
2801 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2802 let result = f(self);
2803 self.current_self_item = previous_value;
2807 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2808 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2809 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2811 let mut new_val = None;
2812 let mut new_id = None;
2813 if let Some(trait_ref) = opt_trait_ref {
2814 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2815 let res = self.smart_resolve_path_fragment(
2819 trait_ref.path.span,
2820 PathSource::Trait(AliasPossibility::No),
2821 CrateLint::SimplePath(trait_ref.ref_id),
2823 if res != Res::Err {
2824 new_id = Some(res.def_id());
2825 let span = trait_ref.path.span;
2826 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2827 self.resolve_path_without_parent_scope(
2832 CrateLint::SimplePath(trait_ref.ref_id),
2835 new_val = Some((module, trait_ref.clone()));
2839 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2840 let result = f(self, new_id);
2841 self.current_trait_ref = original_trait_ref;
2845 fn with_self_rib<F>(&mut self, self_res: Res, f: F)
2846 where F: FnOnce(&mut Resolver<'_>)
2848 let mut self_type_rib = Rib::new(NormalRibKind);
2850 // Plain insert (no renaming, since types are not currently hygienic)
2851 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2852 self.ribs[TypeNS].push(self_type_rib);
2854 self.ribs[TypeNS].pop();
2857 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2858 where F: FnOnce(&mut Resolver<'_>)
2860 let self_res = Res::SelfCtor(impl_id);
2861 let mut self_type_rib = Rib::new(NormalRibKind);
2862 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2863 self.ribs[ValueNS].push(self_type_rib);
2865 self.ribs[ValueNS].pop();
2868 fn resolve_implementation(&mut self,
2869 generics: &Generics,
2870 opt_trait_reference: &Option<TraitRef>,
2873 impl_items: &[ImplItem]) {
2874 debug!("resolve_implementation");
2875 // If applicable, create a rib for the type parameters.
2876 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2877 // Dummy self type for better errors if `Self` is used in the trait path.
2878 this.with_self_rib(Res::SelfTy(None, None), |this| {
2879 // Resolve the trait reference, if necessary.
2880 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2881 let item_def_id = this.definitions.local_def_id(item_id);
2882 this.with_self_rib(Res::SelfTy(trait_id, Some(item_def_id)), |this| {
2883 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2884 // Resolve type arguments in the trait path.
2885 visit::walk_trait_ref(this, trait_ref);
2887 // Resolve the self type.
2888 this.visit_ty(self_type);
2889 // Resolve the generic parameters.
2890 this.visit_generics(generics);
2891 // Resolve the items within the impl.
2892 this.with_current_self_type(self_type, |this| {
2893 this.with_self_struct_ctor_rib(item_def_id, |this| {
2894 debug!("resolve_implementation with_self_struct_ctor_rib");
2895 for impl_item in impl_items {
2896 this.resolve_visibility(&impl_item.vis);
2898 // We also need a new scope for the impl item type parameters.
2899 let generic_params = HasGenericParams(&impl_item.generics,
2901 this.with_generic_param_rib(generic_params, |this| {
2902 use self::ResolutionError::*;
2903 match impl_item.node {
2904 ImplItemKind::Const(..) => {
2906 "resolve_implementation ImplItemKind::Const",
2908 // If this is a trait impl, ensure the const
2910 this.check_trait_item(
2914 |n, s| ConstNotMemberOfTrait(n, s),
2917 this.with_constant_rib(|this| {
2918 visit::walk_impl_item(this, impl_item)
2921 ImplItemKind::Method(..) => {
2922 // If this is a trait impl, ensure the method
2924 this.check_trait_item(impl_item.ident,
2927 |n, s| MethodNotMemberOfTrait(n, s));
2929 visit::walk_impl_item(this, impl_item);
2931 ImplItemKind::Type(ref ty) => {
2932 // If this is a trait impl, ensure the type
2934 this.check_trait_item(impl_item.ident,
2937 |n, s| TypeNotMemberOfTrait(n, s));
2941 ImplItemKind::Existential(ref bounds) => {
2942 // If this is a trait impl, ensure the type
2944 this.check_trait_item(impl_item.ident,
2947 |n, s| TypeNotMemberOfTrait(n, s));
2949 for bound in bounds {
2950 this.visit_param_bound(bound);
2953 ImplItemKind::Macro(_) =>
2954 panic!("unexpanded macro in resolve!"),
2966 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2967 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2969 // If there is a TraitRef in scope for an impl, then the method must be in the
2971 if let Some((module, _)) = self.current_trait_ref {
2972 if self.resolve_ident_in_module(
2973 ModuleOrUniformRoot::Module(module),
2980 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2981 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2986 fn resolve_local(&mut self, local: &Local) {
2987 // Resolve the type.
2988 walk_list!(self, visit_ty, &local.ty);
2990 // Resolve the initializer.
2991 walk_list!(self, visit_expr, &local.init);
2993 // Resolve the pattern.
2994 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2997 // build a map from pattern identifiers to binding-info's.
2998 // this is done hygienically. This could arise for a macro
2999 // that expands into an or-pattern where one 'x' was from the
3000 // user and one 'x' came from the macro.
3001 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
3002 let mut binding_map = FxHashMap::default();
3004 pat.walk(&mut |pat| {
3005 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
3006 if sub_pat.is_some() || match self.partial_res_map.get(&pat.id)
3007 .map(|res| res.base_res()) {
3008 Some(Res::Local(..)) => true,
3011 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
3012 binding_map.insert(ident, binding_info);
3021 // check that all of the arms in an or-pattern have exactly the
3022 // same set of bindings, with the same binding modes for each.
3023 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
3024 if pats.is_empty() {
3028 let mut missing_vars = FxHashMap::default();
3029 let mut inconsistent_vars = FxHashMap::default();
3030 for (i, p) in pats.iter().enumerate() {
3031 let map_i = self.binding_mode_map(&p);
3033 for (j, q) in pats.iter().enumerate() {
3038 let map_j = self.binding_mode_map(&q);
3039 for (&key, &binding_i) in &map_i {
3040 if map_j.is_empty() { // Account for missing bindings when
3041 let binding_error = missing_vars // map_j has none.
3043 .or_insert(BindingError {
3045 origin: BTreeSet::new(),
3046 target: BTreeSet::new(),
3048 binding_error.origin.insert(binding_i.span);
3049 binding_error.target.insert(q.span);
3051 for (&key_j, &binding_j) in &map_j {
3052 match map_i.get(&key_j) {
3053 None => { // missing binding
3054 let binding_error = missing_vars
3056 .or_insert(BindingError {
3058 origin: BTreeSet::new(),
3059 target: BTreeSet::new(),
3061 binding_error.origin.insert(binding_j.span);
3062 binding_error.target.insert(p.span);
3064 Some(binding_i) => { // check consistent binding
3065 if binding_i.binding_mode != binding_j.binding_mode {
3068 .or_insert((binding_j.span, binding_i.span));
3076 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
3077 missing_vars.sort();
3078 for (_, v) in missing_vars {
3080 *v.origin.iter().next().unwrap(),
3081 ResolutionError::VariableNotBoundInPattern(v));
3083 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
3084 inconsistent_vars.sort();
3085 for (name, v) in inconsistent_vars {
3086 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
3090 fn resolve_arm(&mut self, arm: &Arm) {
3091 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3093 let mut bindings_list = FxHashMap::default();
3094 for pattern in &arm.pats {
3095 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
3098 // This has to happen *after* we determine which pat_idents are variants.
3099 self.check_consistent_bindings(&arm.pats);
3101 if let Some(ast::Guard::If(ref expr)) = arm.guard {
3102 self.visit_expr(expr)
3104 self.visit_expr(&arm.body);
3106 self.ribs[ValueNS].pop();
3109 fn resolve_block(&mut self, block: &Block) {
3110 debug!("(resolving block) entering block");
3111 // Move down in the graph, if there's an anonymous module rooted here.
3112 let orig_module = self.current_module;
3113 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
3115 let mut num_macro_definition_ribs = 0;
3116 if let Some(anonymous_module) = anonymous_module {
3117 debug!("(resolving block) found anonymous module, moving down");
3118 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3119 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3120 self.current_module = anonymous_module;
3121 self.finalize_current_module_macro_resolutions();
3123 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3126 // Descend into the block.
3127 for stmt in &block.stmts {
3128 if let ast::StmtKind::Item(ref item) = stmt.node {
3129 if let ast::ItemKind::MacroDef(..) = item.node {
3130 num_macro_definition_ribs += 1;
3131 let res = self.definitions.local_def_id(item.id);
3132 self.ribs[ValueNS].push(Rib::new(MacroDefinition(res)));
3133 self.label_ribs.push(Rib::new(MacroDefinition(res)));
3137 self.visit_stmt(stmt);
3141 self.current_module = orig_module;
3142 for _ in 0 .. num_macro_definition_ribs {
3143 self.ribs[ValueNS].pop();
3144 self.label_ribs.pop();
3146 self.ribs[ValueNS].pop();
3147 if anonymous_module.is_some() {
3148 self.ribs[TypeNS].pop();
3150 debug!("(resolving block) leaving block");
3153 fn fresh_binding(&mut self,
3156 outer_pat_id: NodeId,
3157 pat_src: PatternSource,
3158 bindings: &mut FxHashMap<Ident, NodeId>)
3160 // Add the binding to the local ribs, if it
3161 // doesn't already exist in the bindings map. (We
3162 // must not add it if it's in the bindings map
3163 // because that breaks the assumptions later
3164 // passes make about or-patterns.)
3165 let ident = ident.modern_and_legacy();
3166 let mut res = Res::Local(pat_id);
3167 match bindings.get(&ident).cloned() {
3168 Some(id) if id == outer_pat_id => {
3169 // `Variant(a, a)`, error
3173 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3177 Some(..) if pat_src == PatternSource::FnParam => {
3178 // `fn f(a: u8, a: u8)`, error
3182 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3186 Some(..) if pat_src == PatternSource::Match ||
3187 pat_src == PatternSource::IfLet ||
3188 pat_src == PatternSource::WhileLet => {
3189 // `Variant1(a) | Variant2(a)`, ok
3190 // Reuse definition from the first `a`.
3191 res = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3194 span_bug!(ident.span, "two bindings with the same name from \
3195 unexpected pattern source {:?}", pat_src);
3198 // A completely fresh binding, add to the lists if it's valid.
3199 if ident.name != kw::Invalid {
3200 bindings.insert(ident, outer_pat_id);
3201 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, res);
3209 fn resolve_pattern(&mut self,
3211 pat_src: PatternSource,
3212 // Maps idents to the node ID for the
3213 // outermost pattern that binds them.
3214 bindings: &mut FxHashMap<Ident, NodeId>) {
3215 // Visit all direct subpatterns of this pattern.
3216 let outer_pat_id = pat.id;
3217 pat.walk(&mut |pat| {
3218 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3220 PatKind::Ident(bmode, ident, ref opt_pat) => {
3221 // First try to resolve the identifier as some existing
3222 // entity, then fall back to a fresh binding.
3223 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3225 .and_then(LexicalScopeBinding::item);
3226 let res = binding.map(NameBinding::res).and_then(|res| {
3227 let is_syntactic_ambiguity = opt_pat.is_none() &&
3228 bmode == BindingMode::ByValue(Mutability::Immutable);
3230 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
3231 Res::Def(DefKind::Const, _) if is_syntactic_ambiguity => {
3232 // Disambiguate in favor of a unit struct/variant
3233 // or constant pattern.
3234 self.record_use(ident, ValueNS, binding.unwrap(), false);
3237 Res::Def(DefKind::Ctor(..), _)
3238 | Res::Def(DefKind::Const, _)
3239 | Res::Def(DefKind::Static, _) => {
3240 // This is unambiguously a fresh binding, either syntactically
3241 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3242 // to something unusable as a pattern (e.g., constructor function),
3243 // but we still conservatively report an error, see
3244 // issues/33118#issuecomment-233962221 for one reason why.
3248 ResolutionError::BindingShadowsSomethingUnacceptable(
3249 pat_src.descr(), ident.name, binding.unwrap())
3253 Res::Def(DefKind::Fn, _) | Res::Err => {
3254 // These entities are explicitly allowed
3255 // to be shadowed by fresh bindings.
3259 span_bug!(ident.span, "unexpected resolution for an \
3260 identifier in pattern: {:?}", res);
3263 }).unwrap_or_else(|| {
3264 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3267 self.record_partial_res(pat.id, PartialRes::new(res));
3270 PatKind::TupleStruct(ref path, ..) => {
3271 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3274 PatKind::Path(ref qself, ref path) => {
3275 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3278 PatKind::Struct(ref path, ..) => {
3279 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3287 visit::walk_pat(self, pat);
3290 // High-level and context dependent path resolution routine.
3291 // Resolves the path and records the resolution into definition map.
3292 // If resolution fails tries several techniques to find likely
3293 // resolution candidates, suggest imports or other help, and report
3294 // errors in user friendly way.
3295 fn smart_resolve_path(&mut self,
3297 qself: Option<&QSelf>,
3299 source: PathSource<'_>) {
3300 self.smart_resolve_path_fragment(
3303 &Segment::from_path(path),
3306 CrateLint::SimplePath(id),
3310 fn smart_resolve_path_fragment(&mut self,
3312 qself: Option<&QSelf>,
3315 source: PathSource<'_>,
3316 crate_lint: CrateLint)
3318 let ns = source.namespace();
3319 let is_expected = &|res| source.is_expected(res);
3321 let report_errors = |this: &mut Self, res: Option<Res>| {
3322 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, res);
3323 let def_id = this.current_module.normal_ancestor_id;
3324 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3325 let better = res.is_some();
3326 this.use_injections.push(UseError { err, candidates, node_id, better });
3327 PartialRes::new(Res::Err)
3330 let partial_res = match self.resolve_qpath_anywhere(
3336 source.defer_to_typeck(),
3337 source.global_by_default(),
3340 Some(partial_res) if partial_res.unresolved_segments() == 0 => {
3341 if is_expected(partial_res.base_res()) || partial_res.base_res() == Res::Err {
3344 // Add a temporary hack to smooth the transition to new struct ctor
3345 // visibility rules. See #38932 for more details.
3347 if let Res::Def(DefKind::Struct, def_id) = partial_res.base_res() {
3348 if let Some((ctor_res, ctor_vis))
3349 = self.struct_constructors.get(&def_id).cloned() {
3350 if is_expected(ctor_res) && self.is_accessible(ctor_vis) {
3351 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3352 self.session.buffer_lint(lint, id, span,
3353 "private struct constructors are not usable through \
3354 re-exports in outer modules",
3356 res = Some(PartialRes::new(ctor_res));
3361 res.unwrap_or_else(|| report_errors(self, Some(partial_res.base_res())))
3364 Some(partial_res) if source.defer_to_typeck() => {
3365 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3366 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3367 // it needs to be added to the trait map.
3369 let item_name = path.last().unwrap().ident;
3370 let traits = self.get_traits_containing_item(item_name, ns);
3371 self.trait_map.insert(id, traits);
3374 let mut std_path = vec![Segment::from_ident(Ident::with_empty_ctxt(sym::std))];
3375 std_path.extend(path);
3376 if self.primitive_type_table.primitive_types.contains_key(&path[0].ident.name) {
3377 let cl = CrateLint::No;
3379 if let PathResult::Module(_) | PathResult::NonModule(_) =
3380 self.resolve_path_without_parent_scope(&std_path, ns, false, span, cl)
3382 // check if we wrote `str::from_utf8` instead of `std::str::from_utf8`
3383 let item_span = path.iter().last().map(|segment| segment.ident.span)
3385 debug!("accessed item from `std` submodule as a bare type {:?}", std_path);
3386 let mut hm = self.session.confused_type_with_std_module.borrow_mut();
3387 hm.insert(item_span, span);
3388 // In some places (E0223) we only have access to the full path
3389 hm.insert(span, span);
3394 _ => report_errors(self, None)
3397 if let PathSource::TraitItem(..) = source {} else {
3398 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3399 self.record_partial_res(id, partial_res);
3404 /// Only used in a specific case of type ascription suggestions
3406 fn get_colon_suggestion_span(&self, start: Span) -> Span {
3407 let cm = self.session.source_map();
3408 start.to(cm.next_point(start))
3411 fn type_ascription_suggestion(
3413 err: &mut DiagnosticBuilder<'_>,
3416 debug!("type_ascription_suggetion {:?}", base_span);
3417 let cm = self.session.source_map();
3418 let base_snippet = cm.span_to_snippet(base_span);
3419 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3420 if let Some(sp) = self.current_type_ascription.last() {
3423 // Try to find the `:`; bail on first non-':' / non-whitespace.
3424 sp = cm.next_point(sp);
3425 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3426 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3427 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3429 let mut show_label = true;
3430 if line_sp != line_base_sp {
3431 err.span_suggestion_short(
3433 "did you mean to use `;` here instead?",
3435 Applicability::MaybeIncorrect,
3438 let colon_sp = self.get_colon_suggestion_span(sp);
3439 let after_colon_sp = self.get_colon_suggestion_span(
3440 colon_sp.shrink_to_hi(),
3442 if !cm.span_to_snippet(after_colon_sp).map(|s| s == " ")
3445 err.span_suggestion(
3447 "maybe you meant to write a path separator here",
3449 Applicability::MaybeIncorrect,
3453 if let Ok(base_snippet) = base_snippet {
3454 let mut sp = after_colon_sp;
3456 // Try to find an assignment
3457 sp = cm.next_point(sp);
3458 let snippet = cm.span_to_snippet(sp.to(cm.next_point(sp)));
3460 Ok(ref x) if x.as_str() == "=" => {
3461 err.span_suggestion(
3463 "maybe you meant to write an assignment here",
3464 format!("let {}", base_snippet),
3465 Applicability::MaybeIncorrect,
3470 Ok(ref x) if x.as_str() == "\n" => break,
3478 err.span_label(base_span,
3479 "expecting a type here because of type ascription");
3482 } else if !snippet.trim().is_empty() {
3483 debug!("tried to find type ascription `:` token, couldn't find it");
3493 fn self_type_is_available(&mut self, span: Span) -> bool {
3494 let binding = self.resolve_ident_in_lexical_scope(Ident::with_empty_ctxt(kw::SelfUpper),
3495 TypeNS, None, span);
3496 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3499 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3500 let ident = Ident::new(kw::SelfLower, self_span);
3501 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3502 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3505 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3506 fn resolve_qpath_anywhere(
3509 qself: Option<&QSelf>,
3511 primary_ns: Namespace,
3513 defer_to_typeck: bool,
3514 global_by_default: bool,
3515 crate_lint: CrateLint,
3516 ) -> Option<PartialRes> {
3517 let mut fin_res = None;
3518 // FIXME: can't resolve paths in macro namespace yet, macros are
3519 // processed by the little special hack below.
3520 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3521 if i == 0 || ns != primary_ns {
3522 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3523 // If defer_to_typeck, then resolution > no resolution,
3524 // otherwise full resolution > partial resolution > no resolution.
3525 Some(partial_res) if partial_res.unresolved_segments() == 0 ||
3527 return Some(partial_res),
3528 partial_res => if fin_res.is_none() { fin_res = partial_res },
3532 if primary_ns != MacroNS &&
3533 (self.macro_names.contains(&path[0].ident.modern()) ||
3534 self.builtin_macros.get(&path[0].ident.name).cloned()
3535 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3536 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3537 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3538 // Return some dummy definition, it's enough for error reporting.
3539 return Some(PartialRes::new(Res::Def(
3540 DefKind::Macro(MacroKind::Bang),
3541 DefId::local(CRATE_DEF_INDEX),
3547 /// Handles paths that may refer to associated items.
3551 qself: Option<&QSelf>,
3555 global_by_default: bool,
3556 crate_lint: CrateLint,
3557 ) -> Option<PartialRes> {
3559 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3560 ns={:?}, span={:?}, global_by_default={:?})",
3569 if let Some(qself) = qself {
3570 if qself.position == 0 {
3571 // This is a case like `<T>::B`, where there is no
3572 // trait to resolve. In that case, we leave the `B`
3573 // segment to be resolved by type-check.
3574 return Some(PartialRes::with_unresolved_segments(
3575 Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX)), path.len()
3579 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3581 // Currently, `path` names the full item (`A::B::C`, in
3582 // our example). so we extract the prefix of that that is
3583 // the trait (the slice upto and including
3584 // `qself.position`). And then we recursively resolve that,
3585 // but with `qself` set to `None`.
3587 // However, setting `qself` to none (but not changing the
3588 // span) loses the information about where this path
3589 // *actually* appears, so for the purposes of the crate
3590 // lint we pass along information that this is the trait
3591 // name from a fully qualified path, and this also
3592 // contains the full span (the `CrateLint::QPathTrait`).
3593 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3594 let partial_res = self.smart_resolve_path_fragment(
3597 &path[..=qself.position],
3599 PathSource::TraitItem(ns),
3600 CrateLint::QPathTrait {
3602 qpath_span: qself.path_span,
3606 // The remaining segments (the `C` in our example) will
3607 // have to be resolved by type-check, since that requires doing
3608 // trait resolution.
3609 return Some(PartialRes::with_unresolved_segments(
3610 partial_res.base_res(),
3611 partial_res.unresolved_segments() + path.len() - qself.position - 1,
3615 let result = match self.resolve_path_without_parent_scope(
3622 PathResult::NonModule(path_res) => path_res,
3623 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3624 PartialRes::new(module.res().unwrap())
3626 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3627 // don't report an error right away, but try to fallback to a primitive type.
3628 // So, we are still able to successfully resolve something like
3630 // use std::u8; // bring module u8 in scope
3631 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3632 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3633 // // not to non-existent std::u8::max_value
3636 // Such behavior is required for backward compatibility.
3637 // The same fallback is used when `a` resolves to nothing.
3638 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3639 PathResult::Failed { .. }
3640 if (ns == TypeNS || path.len() > 1) &&
3641 self.primitive_type_table.primitive_types
3642 .contains_key(&path[0].ident.name) => {
3643 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3644 PartialRes::with_unresolved_segments(Res::PrimTy(prim), path.len() - 1)
3646 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3647 PartialRes::new(module.res().unwrap()),
3648 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
3649 resolve_error(self, span, ResolutionError::FailedToResolve { label, suggestion });
3650 PartialRes::new(Res::Err)
3652 PathResult::Module(..) | PathResult::Failed { .. } => return None,
3653 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3656 if path.len() > 1 && !global_by_default && result.base_res() != Res::Err &&
3657 path[0].ident.name != kw::PathRoot &&
3658 path[0].ident.name != kw::DollarCrate {
3659 let unqualified_result = {
3660 match self.resolve_path_without_parent_scope(
3661 &[*path.last().unwrap()],
3667 PathResult::NonModule(path_res) => path_res.base_res(),
3668 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3669 module.res().unwrap(),
3670 _ => return Some(result),
3673 if result.base_res() == unqualified_result {
3674 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3675 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3682 fn resolve_path_without_parent_scope(
3685 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3688 crate_lint: CrateLint,
3689 ) -> PathResult<'a> {
3690 // Macro and import paths must have full parent scope available during resolution,
3691 // other paths will do okay with parent module alone.
3692 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3693 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3694 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3700 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3701 parent_scope: &ParentScope<'a>,
3704 crate_lint: CrateLint,
3705 ) -> PathResult<'a> {
3706 let mut module = None;
3707 let mut allow_super = true;
3708 let mut second_binding = None;
3709 self.current_module = parent_scope.module;
3712 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3713 path_span={:?}, crate_lint={:?})",
3721 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3722 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3723 let record_segment_res = |this: &mut Self, res| {
3725 if let Some(id) = id {
3726 if !this.partial_res_map.contains_key(&id) {
3727 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3728 this.record_partial_res(id, PartialRes::new(res));
3734 let is_last = i == path.len() - 1;
3735 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3736 let name = ident.name;
3738 allow_super &= ns == TypeNS &&
3739 (name == kw::SelfLower ||
3743 if allow_super && name == kw::Super {
3744 let mut ctxt = ident.span.ctxt().modern();
3745 let self_module = match i {
3746 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3748 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3752 if let Some(self_module) = self_module {
3753 if let Some(parent) = self_module.parent {
3754 module = Some(ModuleOrUniformRoot::Module(
3755 self.resolve_self(&mut ctxt, parent)));
3759 let msg = "there are too many initial `super`s.".to_string();
3760 return PathResult::Failed {
3764 is_error_from_last_segment: false,
3768 if name == kw::SelfLower {
3769 let mut ctxt = ident.span.ctxt().modern();
3770 module = Some(ModuleOrUniformRoot::Module(
3771 self.resolve_self(&mut ctxt, self.current_module)));
3774 if name == kw::PathRoot && ident.span.rust_2018() {
3775 module = Some(ModuleOrUniformRoot::ExternPrelude);
3778 if name == kw::PathRoot &&
3779 ident.span.rust_2015() && self.session.rust_2018() {
3780 // `::a::b` from 2015 macro on 2018 global edition
3781 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3784 if name == kw::PathRoot ||
3785 name == kw::Crate ||
3786 name == kw::DollarCrate {
3787 // `::a::b`, `crate::a::b` or `$crate::a::b`
3788 module = Some(ModuleOrUniformRoot::Module(
3789 self.resolve_crate_root(ident)));
3795 // Report special messages for path segment keywords in wrong positions.
3796 if ident.is_path_segment_keyword() && i != 0 {
3797 let name_str = if name == kw::PathRoot {
3798 "crate root".to_string()
3800 format!("`{}`", name)
3802 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
3803 format!("global paths cannot start with {}", name_str)
3805 format!("{} in paths can only be used in start position", name_str)
3807 return PathResult::Failed {
3811 is_error_from_last_segment: false,
3815 let binding = if let Some(module) = module {
3816 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3817 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3818 assert!(ns == TypeNS);
3819 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3820 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3821 record_used, path_span)
3823 let record_used_id =
3824 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3825 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3826 // we found a locally-imported or available item/module
3827 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3828 // we found a local variable or type param
3829 Some(LexicalScopeBinding::Res(res))
3830 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3831 record_segment_res(self, res);
3832 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3836 _ => Err(Determinacy::determined(record_used)),
3843 second_binding = Some(binding);
3845 let res = binding.res();
3846 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
3847 if let Some(next_module) = binding.module() {
3848 module = Some(ModuleOrUniformRoot::Module(next_module));
3849 record_segment_res(self, res);
3850 } else if res == Res::ToolMod && i + 1 != path.len() {
3851 if binding.is_import() {
3852 self.session.struct_span_err(
3853 ident.span, "cannot use a tool module through an import"
3855 binding.span, "the tool module imported here"
3858 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
3859 return PathResult::NonModule(PartialRes::new(res));
3860 } else if res == Res::Err {
3861 return PathResult::NonModule(PartialRes::new(Res::Err));
3862 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3863 self.lint_if_path_starts_with_module(
3869 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3870 res, path.len() - i - 1
3873 let label = format!(
3874 "`{}` is {} {}, not a module",
3880 return PathResult::Failed {
3884 is_error_from_last_segment: is_last,
3888 Err(Undetermined) => return PathResult::Indeterminate,
3889 Err(Determined) => {
3890 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3891 if opt_ns.is_some() && !module.is_normal() {
3892 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3893 module.res().unwrap(), path.len() - i
3897 let module_res = match module {
3898 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
3901 let (label, suggestion) = if module_res == self.graph_root.res() {
3902 let is_mod = |res| {
3903 match res { Res::Def(DefKind::Mod, _) => true, _ => false }
3905 let mut candidates =
3906 self.lookup_import_candidates(ident, TypeNS, is_mod);
3907 candidates.sort_by_cached_key(|c| {
3908 (c.path.segments.len(), c.path.to_string())
3910 if let Some(candidate) = candidates.get(0) {
3912 String::from("unresolved import"),
3914 vec![(ident.span, candidate.path.to_string())],
3915 String::from("a similar path exists"),
3916 Applicability::MaybeIncorrect,
3919 } else if !ident.is_reserved() {
3920 (format!("maybe a missing `extern crate {};`?", ident), None)
3922 // the parser will already have complained about the keyword being used
3923 return PathResult::NonModule(PartialRes::new(Res::Err));
3926 (format!("use of undeclared type or module `{}`", ident), None)
3928 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
3930 return PathResult::Failed {
3934 is_error_from_last_segment: is_last,
3940 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3942 PathResult::Module(match module {
3943 Some(module) => module,
3944 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3945 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3949 fn lint_if_path_starts_with_module(
3951 crate_lint: CrateLint,
3954 second_binding: Option<&NameBinding<'_>>,
3956 let (diag_id, diag_span) = match crate_lint {
3957 CrateLint::No => return,
3958 CrateLint::SimplePath(id) => (id, path_span),
3959 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3960 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3963 let first_name = match path.get(0) {
3964 // In the 2018 edition this lint is a hard error, so nothing to do
3965 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3969 // We're only interested in `use` paths which should start with
3970 // `{{root}}` currently.
3971 if first_name != kw::PathRoot {
3976 // If this import looks like `crate::...` it's already good
3977 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
3978 // Otherwise go below to see if it's an extern crate
3980 // If the path has length one (and it's `PathRoot` most likely)
3981 // then we don't know whether we're gonna be importing a crate or an
3982 // item in our crate. Defer this lint to elsewhere
3986 // If the first element of our path was actually resolved to an
3987 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3988 // warning, this looks all good!
3989 if let Some(binding) = second_binding {
3990 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3991 // Careful: we still want to rewrite paths from
3992 // renamed extern crates.
3993 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3999 let diag = lint::builtin::BuiltinLintDiagnostics
4000 ::AbsPathWithModule(diag_span);
4001 self.session.buffer_lint_with_diagnostic(
4002 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
4004 "absolute paths must start with `self`, `super`, \
4005 `crate`, or an external crate name in the 2018 edition",
4009 // Resolve a local definition, potentially adjusting for closures.
4010 fn adjust_local_res(&mut self,
4015 span: Span) -> Res {
4016 debug!("adjust_local_res");
4017 let ribs = &self.ribs[ns][rib_index + 1..];
4019 // An invalid forward use of a type parameter from a previous default.
4020 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4022 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4024 assert_eq!(res, Res::Err);
4028 // An invalid use of a type parameter as the type of a const parameter.
4029 if let TyParamAsConstParamTy = self.ribs[ns][rib_index].kind {
4031 resolve_error(self, span, ResolutionError::ConstParamDependentOnTypeParam);
4033 assert_eq!(res, Res::Err);
4039 span_bug!(span, "unexpected {:?} in bindings", res)
4041 Res::Local(var_id) => {
4042 use ResolutionError::*;
4043 let mut res_err = None;
4047 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4048 ForwardTyParamBanRibKind | TyParamAsConstParamTy => {
4049 // Nothing to do. Continue.
4051 ClosureRibKind(function_id) => {
4052 res = Res::Upvar(var_id);
4053 match self.upvars.entry(function_id).or_default().entry(var_id) {
4054 indexmap::map::Entry::Occupied(_) => continue,
4055 indexmap::map::Entry::Vacant(entry) => {
4057 entry.insert(Upvar { span });
4062 ItemRibKind | FnItemRibKind | AssocItemRibKind => {
4063 // This was an attempt to access an upvar inside a
4064 // named function item. This is not allowed, so we
4067 // We don't immediately trigger a resolve error, because
4068 // we want certain other resolution errors (namely those
4069 // emitted for `ConstantItemRibKind` below) to take
4071 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
4074 ConstantItemRibKind => {
4075 // Still doesn't deal with upvars
4077 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
4083 if let Some(res_err) = res_err {
4084 resolve_error(self, span, res_err);
4088 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
4091 NormalRibKind | AssocItemRibKind | ClosureRibKind(..) |
4092 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4093 ConstantItemRibKind | TyParamAsConstParamTy => {
4094 // Nothing to do. Continue.
4096 ItemRibKind | FnItemRibKind => {
4097 // This was an attempt to use a type parameter outside its scope.
4102 ResolutionError::GenericParamsFromOuterFunction(res),
4110 Res::Def(DefKind::ConstParam, _) => {
4111 let mut ribs = ribs.iter().peekable();
4112 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
4113 // When declaring const parameters inside function signatures, the first rib
4114 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
4115 // (spuriously) conflicting with the const param.
4119 if let ItemRibKind | FnItemRibKind = rib.kind {
4120 // This was an attempt to use a const parameter outside its scope.
4125 ResolutionError::GenericParamsFromOuterFunction(res),
4137 fn lookup_assoc_candidate<FilterFn>(&mut self,
4140 filter_fn: FilterFn)
4141 -> Option<AssocSuggestion>
4142 where FilterFn: Fn(Res) -> bool
4144 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4146 TyKind::Path(None, _) => Some(t.id),
4147 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4148 // This doesn't handle the remaining `Ty` variants as they are not
4149 // that commonly the self_type, it might be interesting to provide
4150 // support for those in future.
4155 // Fields are generally expected in the same contexts as locals.
4156 if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
4157 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4158 // Look for a field with the same name in the current self_type.
4159 if let Some(resolution) = self.partial_res_map.get(&node_id) {
4160 match resolution.base_res() {
4161 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did)
4162 if resolution.unresolved_segments() == 0 => {
4163 if let Some(field_names) = self.field_names.get(&did) {
4164 if field_names.iter().any(|&field_name| ident.name == field_name) {
4165 return Some(AssocSuggestion::Field);
4175 // Look for associated items in the current trait.
4176 if let Some((module, _)) = self.current_trait_ref {
4177 if let Ok(binding) = self.resolve_ident_in_module(
4178 ModuleOrUniformRoot::Module(module),
4185 let res = binding.res();
4187 return Some(if self.has_self.contains(&res.def_id()) {
4188 AssocSuggestion::MethodWithSelf
4190 AssocSuggestion::AssocItem
4199 fn lookup_typo_candidate<FilterFn>(
4203 filter_fn: FilterFn,
4205 ) -> Option<TypoSuggestion>
4207 FilterFn: Fn(Res) -> bool,
4209 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4210 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4211 if let Some(binding) = resolution.borrow().binding {
4212 if !ident.is_gensymed() && filter_fn(binding.res()) {
4213 names.push(TypoSuggestion {
4214 candidate: ident.name,
4215 article: binding.res().article(),
4216 kind: binding.res().descr(),
4223 let mut names = Vec::new();
4224 if path.len() == 1 {
4225 // Search in lexical scope.
4226 // Walk backwards up the ribs in scope and collect candidates.
4227 for rib in self.ribs[ns].iter().rev() {
4228 // Locals and type parameters
4229 for (ident, &res) in &rib.bindings {
4230 if !ident.is_gensymed() && filter_fn(res) {
4231 names.push(TypoSuggestion {
4232 candidate: ident.name,
4233 article: res.article(),
4239 if let ModuleRibKind(module) = rib.kind {
4240 // Items from this module
4241 add_module_candidates(module, &mut names);
4243 if let ModuleKind::Block(..) = module.kind {
4244 // We can see through blocks
4246 // Items from the prelude
4247 if !module.no_implicit_prelude {
4248 names.extend(self.extern_prelude.clone().iter().flat_map(|(ident, _)| {
4250 .maybe_process_path_extern(ident.name, ident.span)
4251 .and_then(|crate_id| {
4252 let crate_mod = Res::Def(
4256 index: CRATE_DEF_INDEX,
4260 if !ident.is_gensymed() && filter_fn(crate_mod) {
4261 Some(TypoSuggestion {
4262 candidate: ident.name,
4272 if let Some(prelude) = self.prelude {
4273 add_module_candidates(prelude, &mut names);
4280 // Add primitive types to the mix
4281 if filter_fn(Res::PrimTy(Bool)) {
4283 self.primitive_type_table.primitive_types
4289 kind: "primitive type",
4295 // Search in module.
4296 let mod_path = &path[..path.len() - 1];
4297 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4298 mod_path, Some(TypeNS), false, span, CrateLint::No
4300 if let ModuleOrUniformRoot::Module(module) = module {
4301 add_module_candidates(module, &mut names);
4306 let name = path[path.len() - 1].ident.name;
4307 // Make sure error reporting is deterministic.
4308 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4310 match find_best_match_for_name(
4311 names.iter().map(|suggestion| &suggestion.candidate),
4315 Some(found) if found != name => names
4317 .find(|suggestion| suggestion.candidate == found),
4322 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4323 where F: FnOnce(&mut Resolver<'_>)
4325 if let Some(label) = label {
4326 self.unused_labels.insert(id, label.ident.span);
4327 self.with_label_rib(|this| {
4328 let ident = label.ident.modern_and_legacy();
4329 this.label_ribs.last_mut().unwrap().bindings.insert(ident, id);
4337 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4338 self.with_resolved_label(label, id, |this| this.visit_block(block));
4341 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4342 // First, record candidate traits for this expression if it could
4343 // result in the invocation of a method call.
4345 self.record_candidate_traits_for_expr_if_necessary(expr);
4347 // Next, resolve the node.
4349 ExprKind::Path(ref qself, ref path) => {
4350 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4351 visit::walk_expr(self, expr);
4354 ExprKind::Struct(ref path, ..) => {
4355 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4356 visit::walk_expr(self, expr);
4359 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4360 let node_id = self.search_label(label.ident, |rib, ident| {
4361 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4365 // Search again for close matches...
4366 // Picks the first label that is "close enough", which is not necessarily
4367 // the closest match
4368 let close_match = self.search_label(label.ident, |rib, ident| {
4369 let names = rib.bindings.iter().filter_map(|(id, _)| {
4370 if id.span.ctxt() == label.ident.span.ctxt() {
4376 find_best_match_for_name(names, &*ident.as_str(), None)
4378 self.record_partial_res(expr.id, PartialRes::new(Res::Err));
4381 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4385 // Since this res is a label, it is never read.
4386 self.label_res_map.insert(expr.id, node_id);
4387 self.unused_labels.remove(&node_id);
4391 // visit `break` argument if any
4392 visit::walk_expr(self, expr);
4395 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4396 self.visit_expr(subexpression);
4398 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4399 let mut bindings_list = FxHashMap::default();
4401 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4403 // This has to happen *after* we determine which pat_idents are variants
4404 self.check_consistent_bindings(pats);
4405 self.visit_block(if_block);
4406 self.ribs[ValueNS].pop();
4408 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4411 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4413 ExprKind::While(ref subexpression, ref block, label) => {
4414 self.with_resolved_label(label, expr.id, |this| {
4415 this.visit_expr(subexpression);
4416 this.visit_block(block);
4420 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4421 self.with_resolved_label(label, expr.id, |this| {
4422 this.visit_expr(subexpression);
4423 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4424 let mut bindings_list = FxHashMap::default();
4426 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4428 // This has to happen *after* we determine which pat_idents are variants.
4429 this.check_consistent_bindings(pats);
4430 this.visit_block(block);
4431 this.ribs[ValueNS].pop();
4435 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4436 self.visit_expr(subexpression);
4437 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4438 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4440 self.resolve_labeled_block(label, expr.id, block);
4442 self.ribs[ValueNS].pop();
4445 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4447 // Equivalent to `visit::walk_expr` + passing some context to children.
4448 ExprKind::Field(ref subexpression, _) => {
4449 self.resolve_expr(subexpression, Some(expr));
4451 ExprKind::MethodCall(ref segment, ref arguments) => {
4452 let mut arguments = arguments.iter();
4453 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4454 for argument in arguments {
4455 self.resolve_expr(argument, None);
4457 self.visit_path_segment(expr.span, segment);
4460 ExprKind::Call(ref callee, ref arguments) => {
4461 self.resolve_expr(callee, Some(expr));
4462 for argument in arguments {
4463 self.resolve_expr(argument, None);
4466 ExprKind::Type(ref type_expr, _) => {
4467 self.current_type_ascription.push(type_expr.span);
4468 visit::walk_expr(self, expr);
4469 self.current_type_ascription.pop();
4471 // Resolve the body of async exprs inside the async closure to which they desugar
4472 ExprKind::Async(_, async_closure_id, ref block) => {
4473 let rib_kind = ClosureRibKind(async_closure_id);
4474 self.ribs[ValueNS].push(Rib::new(rib_kind));
4475 self.label_ribs.push(Rib::new(rib_kind));
4476 self.visit_block(&block);
4477 self.label_ribs.pop();
4478 self.ribs[ValueNS].pop();
4480 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4481 // resolve the arguments within the proper scopes so that usages of them inside the
4482 // closure are detected as upvars rather than normal closure arg usages.
4484 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4485 ref fn_decl, ref body, _span,
4487 let rib_kind = ClosureRibKind(expr.id);
4488 self.ribs[ValueNS].push(Rib::new(rib_kind));
4489 self.label_ribs.push(Rib::new(rib_kind));
4490 // Resolve arguments:
4491 let mut bindings_list = FxHashMap::default();
4492 for argument in &fn_decl.inputs {
4493 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4494 self.visit_ty(&argument.ty);
4496 // No need to resolve return type-- the outer closure return type is
4497 // FunctionRetTy::Default
4499 // Now resolve the inner closure
4501 let rib_kind = ClosureRibKind(inner_closure_id);
4502 self.ribs[ValueNS].push(Rib::new(rib_kind));
4503 self.label_ribs.push(Rib::new(rib_kind));
4504 // No need to resolve arguments: the inner closure has none.
4505 // Resolve the return type:
4506 visit::walk_fn_ret_ty(self, &fn_decl.output);
4508 self.visit_expr(body);
4509 self.label_ribs.pop();
4510 self.ribs[ValueNS].pop();
4512 self.label_ribs.pop();
4513 self.ribs[ValueNS].pop();
4516 visit::walk_expr(self, expr);
4521 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4523 ExprKind::Field(_, ident) => {
4524 // FIXME(#6890): Even though you can't treat a method like a
4525 // field, we need to add any trait methods we find that match
4526 // the field name so that we can do some nice error reporting
4527 // later on in typeck.
4528 let traits = self.get_traits_containing_item(ident, ValueNS);
4529 self.trait_map.insert(expr.id, traits);
4531 ExprKind::MethodCall(ref segment, ..) => {
4532 debug!("(recording candidate traits for expr) recording traits for {}",
4534 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4535 self.trait_map.insert(expr.id, traits);
4543 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4544 -> Vec<TraitCandidate> {
4545 debug!("(getting traits containing item) looking for '{}'", ident.name);
4547 let mut found_traits = Vec::new();
4548 // Look for the current trait.
4549 if let Some((module, _)) = self.current_trait_ref {
4550 if self.resolve_ident_in_module(
4551 ModuleOrUniformRoot::Module(module),
4558 let def_id = module.def_id().unwrap();
4559 found_traits.push(TraitCandidate { def_id: def_id, import_ids: smallvec![] });
4563 ident.span = ident.span.modern();
4564 let mut search_module = self.current_module;
4566 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4567 search_module = unwrap_or!(
4568 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4572 if let Some(prelude) = self.prelude {
4573 if !search_module.no_implicit_prelude {
4574 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4581 fn get_traits_in_module_containing_item(&mut self,
4585 found_traits: &mut Vec<TraitCandidate>) {
4586 assert!(ns == TypeNS || ns == ValueNS);
4587 let mut traits = module.traits.borrow_mut();
4588 if traits.is_none() {
4589 let mut collected_traits = Vec::new();
4590 module.for_each_child(|name, ns, binding| {
4591 if ns != TypeNS { return }
4592 match binding.res() {
4593 Res::Def(DefKind::Trait, _) |
4594 Res::Def(DefKind::TraitAlias, _) => collected_traits.push((name, binding)),
4598 *traits = Some(collected_traits.into_boxed_slice());
4601 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4602 // Traits have pseudo-modules that can be used to search for the given ident.
4603 if let Some(module) = binding.module() {
4604 let mut ident = ident;
4605 if ident.span.glob_adjust(
4607 binding.span.ctxt().modern(),
4611 if self.resolve_ident_in_module_unadjusted(
4612 ModuleOrUniformRoot::Module(module),
4618 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4619 let trait_def_id = module.def_id().unwrap();
4620 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4622 } else if let Res::Def(DefKind::TraitAlias, _) = binding.res() {
4623 // For now, just treat all trait aliases as possible candidates, since we don't
4624 // know if the ident is somewhere in the transitive bounds.
4625 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4626 let trait_def_id = binding.res().def_id();
4627 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4629 bug!("candidate is not trait or trait alias?")
4634 fn find_transitive_imports(&mut self, mut kind: &NameBindingKind<'_>,
4635 trait_name: Ident) -> SmallVec<[NodeId; 1]> {
4636 let mut import_ids = smallvec![];
4637 while let NameBindingKind::Import { directive, binding, .. } = kind {
4638 self.maybe_unused_trait_imports.insert(directive.id);
4639 self.add_to_glob_map(&directive, trait_name);
4640 import_ids.push(directive.id);
4641 kind = &binding.kind;
4646 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4647 lookup_ident: Ident,
4648 namespace: Namespace,
4649 start_module: &'a ModuleData<'a>,
4651 filter_fn: FilterFn)
4652 -> Vec<ImportSuggestion>
4653 where FilterFn: Fn(Res) -> bool
4655 let mut candidates = Vec::new();
4656 let mut seen_modules = FxHashSet::default();
4657 let not_local_module = crate_name.name != kw::Crate;
4658 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4660 while let Some((in_module,
4662 in_module_is_extern)) = worklist.pop() {
4663 self.populate_module_if_necessary(in_module);
4665 // We have to visit module children in deterministic order to avoid
4666 // instabilities in reported imports (#43552).
4667 in_module.for_each_child_stable(|ident, ns, name_binding| {
4668 // avoid imports entirely
4669 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4670 // avoid non-importable candidates as well
4671 if !name_binding.is_importable() { return; }
4673 // collect results based on the filter function
4674 if ident.name == lookup_ident.name && ns == namespace {
4675 let res = name_binding.res();
4678 let mut segms = path_segments.clone();
4679 if lookup_ident.span.rust_2018() {
4680 // crate-local absolute paths start with `crate::` in edition 2018
4681 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4683 0, ast::PathSegment::from_ident(crate_name)
4687 segms.push(ast::PathSegment::from_ident(ident));
4689 span: name_binding.span,
4692 // the entity is accessible in the following cases:
4693 // 1. if it's defined in the same crate, it's always
4694 // accessible (since private entities can be made public)
4695 // 2. if it's defined in another crate, it's accessible
4696 // only if both the module is public and the entity is
4697 // declared as public (due to pruning, we don't explore
4698 // outside crate private modules => no need to check this)
4699 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4700 let did = match res {
4701 Res::Def(DefKind::Ctor(..), did) => self.parent(did),
4702 _ => res.opt_def_id(),
4704 candidates.push(ImportSuggestion { did, path });
4709 // collect submodules to explore
4710 if let Some(module) = name_binding.module() {
4712 let mut path_segments = path_segments.clone();
4713 path_segments.push(ast::PathSegment::from_ident(ident));
4715 let is_extern_crate_that_also_appears_in_prelude =
4716 name_binding.is_extern_crate() &&
4717 lookup_ident.span.rust_2018();
4719 let is_visible_to_user =
4720 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4722 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4723 // add the module to the lookup
4724 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4725 if seen_modules.insert(module.def_id().unwrap()) {
4726 worklist.push((module, path_segments, is_extern));
4736 /// When name resolution fails, this method can be used to look up candidate
4737 /// entities with the expected name. It allows filtering them using the
4738 /// supplied predicate (which should be used to only accept the types of
4739 /// definitions expected, e.g., traits). The lookup spans across all crates.
4741 /// N.B., the method does not look into imports, but this is not a problem,
4742 /// since we report the definitions (thus, the de-aliased imports).
4743 fn lookup_import_candidates<FilterFn>(&mut self,
4744 lookup_ident: Ident,
4745 namespace: Namespace,
4746 filter_fn: FilterFn)
4747 -> Vec<ImportSuggestion>
4748 where FilterFn: Fn(Res) -> bool
4750 let mut suggestions = self.lookup_import_candidates_from_module(
4751 lookup_ident, namespace, self.graph_root, Ident::with_empty_ctxt(kw::Crate), &filter_fn
4754 if lookup_ident.span.rust_2018() {
4755 let extern_prelude_names = self.extern_prelude.clone();
4756 for (ident, _) in extern_prelude_names.into_iter() {
4757 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4759 let crate_root = self.get_module(DefId {
4761 index: CRATE_DEF_INDEX,
4763 self.populate_module_if_necessary(&crate_root);
4765 suggestions.extend(self.lookup_import_candidates_from_module(
4766 lookup_ident, namespace, crate_root, ident, &filter_fn));
4774 fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
4775 let mut result = None;
4776 let mut seen_modules = FxHashSet::default();
4777 let mut worklist = vec![(self.graph_root, Vec::new())];
4779 while let Some((in_module, path_segments)) = worklist.pop() {
4780 // abort if the module is already found
4781 if result.is_some() { break; }
4783 self.populate_module_if_necessary(in_module);
4785 in_module.for_each_child_stable(|ident, _, name_binding| {
4786 // abort if the module is already found or if name_binding is private external
4787 if result.is_some() || !name_binding.vis.is_visible_locally() {
4790 if let Some(module) = name_binding.module() {
4792 let mut path_segments = path_segments.clone();
4793 path_segments.push(ast::PathSegment::from_ident(ident));
4794 let module_def_id = module.def_id().unwrap();
4795 if module_def_id == def_id {
4797 span: name_binding.span,
4798 segments: path_segments,
4800 result = Some((module, ImportSuggestion { did: Some(def_id), path }));
4802 // add the module to the lookup
4803 if seen_modules.insert(module_def_id) {
4804 worklist.push((module, path_segments));
4814 fn collect_enum_variants(&mut self, def_id: DefId) -> Option<Vec<Path>> {
4815 self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
4816 self.populate_module_if_necessary(enum_module);
4818 let mut variants = Vec::new();
4819 enum_module.for_each_child_stable(|ident, _, name_binding| {
4820 if let Res::Def(DefKind::Variant, _) = name_binding.res() {
4821 let mut segms = enum_import_suggestion.path.segments.clone();
4822 segms.push(ast::PathSegment::from_ident(ident));
4823 variants.push(Path {
4824 span: name_binding.span,
4833 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
4834 debug!("(recording res) recording {:?} for {}", resolution, node_id);
4835 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
4836 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4840 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4842 ast::VisibilityKind::Public => ty::Visibility::Public,
4843 ast::VisibilityKind::Crate(..) => {
4844 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4846 ast::VisibilityKind::Inherited => {
4847 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4849 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4850 // For visibilities we are not ready to provide correct implementation of "uniform
4851 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4852 // On 2015 edition visibilities are resolved as crate-relative by default,
4853 // so we are prepending a root segment if necessary.
4854 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4855 let crate_root = if ident.is_path_segment_keyword() {
4857 } else if ident.span.rust_2018() {
4858 let msg = "relative paths are not supported in visibilities on 2018 edition";
4859 self.session.struct_span_err(ident.span, msg)
4863 format!("crate::{}", path),
4864 Applicability::MaybeIncorrect,
4867 return ty::Visibility::Public;
4869 let ctxt = ident.span.ctxt();
4870 Some(Segment::from_ident(Ident::new(
4871 kw::PathRoot, path.span.shrink_to_lo().with_ctxt(ctxt)
4875 let segments = crate_root.into_iter()
4876 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4877 let res = self.smart_resolve_path_fragment(
4882 PathSource::Visibility,
4883 CrateLint::SimplePath(id),
4885 if res == Res::Err {
4886 ty::Visibility::Public
4888 let vis = ty::Visibility::Restricted(res.def_id());
4889 if self.is_accessible(vis) {
4892 self.session.span_err(path.span, "visibilities can only be restricted \
4893 to ancestor modules");
4894 ty::Visibility::Public
4901 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4902 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4905 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4906 vis.is_accessible_from(module.normal_ancestor_id, self)
4909 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4910 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4911 if !ptr::eq(module, old_module) {
4912 span_bug!(binding.span, "parent module is reset for binding");
4917 fn disambiguate_legacy_vs_modern(
4919 legacy: &'a NameBinding<'a>,
4920 modern: &'a NameBinding<'a>,
4922 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4923 // is disambiguated to mitigate regressions from macro modularization.
4924 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4925 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4926 self.binding_parent_modules.get(&PtrKey(modern))) {
4927 (Some(legacy), Some(modern)) =>
4928 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4929 modern.is_ancestor_of(legacy),
4934 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4935 if b.span.is_dummy() {
4936 let add_built_in = match b.res() {
4937 // These already contain the "built-in" prefix or look bad with it.
4938 Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod => false,
4941 let (built_in, from) = if from_prelude {
4942 ("", " from prelude")
4943 } else if b.is_extern_crate() && !b.is_import() &&
4944 self.session.opts.externs.get(&ident.as_str()).is_some() {
4945 ("", " passed with `--extern`")
4946 } else if add_built_in {
4952 let article = if built_in.is_empty() { b.article() } else { "a" };
4953 format!("{a}{built_in} {thing}{from}",
4954 a = article, thing = b.descr(), built_in = built_in, from = from)
4956 let introduced = if b.is_import() { "imported" } else { "defined" };
4957 format!("the {thing} {introduced} here",
4958 thing = b.descr(), introduced = introduced)
4962 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4963 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4964 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4965 // We have to print the span-less alternative first, otherwise formatting looks bad.
4966 (b2, b1, misc2, misc1, true)
4968 (b1, b2, misc1, misc2, false)
4971 let mut err = struct_span_err!(self.session, ident.span, E0659,
4972 "`{ident}` is ambiguous ({why})",
4973 ident = ident, why = kind.descr());
4974 err.span_label(ident.span, "ambiguous name");
4976 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4977 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4978 let note_msg = format!("`{ident}` could{also} refer to {what}",
4979 ident = ident, also = also, what = what);
4981 let mut help_msgs = Vec::new();
4982 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4983 kind == AmbiguityKind::GlobVsExpanded ||
4984 kind == AmbiguityKind::GlobVsOuter &&
4985 swapped != also.is_empty()) {
4986 help_msgs.push(format!("consider adding an explicit import of \
4987 `{ident}` to disambiguate", ident = ident))
4989 if b.is_extern_crate() && ident.span.rust_2018() {
4990 help_msgs.push(format!(
4991 "use `::{ident}` to refer to this {thing} unambiguously",
4992 ident = ident, thing = b.descr(),
4995 if misc == AmbiguityErrorMisc::SuggestCrate {
4996 help_msgs.push(format!(
4997 "use `crate::{ident}` to refer to this {thing} unambiguously",
4998 ident = ident, thing = b.descr(),
5000 } else if misc == AmbiguityErrorMisc::SuggestSelf {
5001 help_msgs.push(format!(
5002 "use `self::{ident}` to refer to this {thing} unambiguously",
5003 ident = ident, thing = b.descr(),
5007 err.span_note(b.span, ¬e_msg);
5008 for (i, help_msg) in help_msgs.iter().enumerate() {
5009 let or = if i == 0 { "" } else { "or " };
5010 err.help(&format!("{}{}", or, help_msg));
5014 could_refer_to(b1, misc1, "");
5015 could_refer_to(b2, misc2, " also");
5019 fn report_errors(&mut self, krate: &Crate) {
5020 self.report_with_use_injections(krate);
5022 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
5023 let msg = "macro-expanded `macro_export` macros from the current crate \
5024 cannot be referred to by absolute paths";
5025 self.session.buffer_lint_with_diagnostic(
5026 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
5027 CRATE_NODE_ID, span_use, msg,
5028 lint::builtin::BuiltinLintDiagnostics::
5029 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
5033 for ambiguity_error in &self.ambiguity_errors {
5034 self.report_ambiguity_error(ambiguity_error);
5037 let mut reported_spans = FxHashSet::default();
5038 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
5039 if reported_spans.insert(dedup_span) {
5040 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
5041 binding.descr(), ident.name);
5046 fn report_with_use_injections(&mut self, krate: &Crate) {
5047 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5048 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5049 if !candidates.is_empty() {
5050 show_candidates(&mut err, span, &candidates, better, found_use);
5056 fn report_conflict<'b>(&mut self,
5060 new_binding: &NameBinding<'b>,
5061 old_binding: &NameBinding<'b>) {
5062 // Error on the second of two conflicting names
5063 if old_binding.span.lo() > new_binding.span.lo() {
5064 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5067 let container = match parent.kind {
5068 ModuleKind::Def(DefKind::Mod, _, _) => "module",
5069 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
5070 ModuleKind::Block(..) => "block",
5074 let old_noun = match old_binding.is_import() {
5076 false => "definition",
5079 let new_participle = match new_binding.is_import() {
5084 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5086 if let Some(s) = self.name_already_seen.get(&name) {
5092 let old_kind = match (ns, old_binding.module()) {
5093 (ValueNS, _) => "value",
5094 (MacroNS, _) => "macro",
5095 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5096 (TypeNS, Some(module)) if module.is_normal() => "module",
5097 (TypeNS, Some(module)) if module.is_trait() => "trait",
5098 (TypeNS, _) => "type",
5101 let msg = format!("the name `{}` is defined multiple times", name);
5103 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5104 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5105 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5106 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5107 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5109 _ => match (old_binding.is_import(), new_binding.is_import()) {
5110 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5111 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5112 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5116 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5121 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5123 self.session.source_map().def_span(old_binding.span),
5124 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5127 // See https://github.com/rust-lang/rust/issues/32354
5128 use NameBindingKind::Import;
5129 let directive = match (&new_binding.kind, &old_binding.kind) {
5130 // If there are two imports where one or both have attributes then prefer removing the
5131 // import without attributes.
5132 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5133 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5134 (new.has_attributes || old.has_attributes)
5136 if old.has_attributes {
5137 Some((new, new_binding.span, true))
5139 Some((old, old_binding.span, true))
5142 // Otherwise prioritize the new binding.
5143 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5144 Some((directive, new_binding.span, other.is_import())),
5145 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5146 Some((directive, old_binding.span, other.is_import())),
5150 // Check if the target of the use for both bindings is the same.
5151 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
5152 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5153 let from_item = self.extern_prelude.get(&ident)
5154 .map(|entry| entry.introduced_by_item)
5156 // Only suggest removing an import if both bindings are to the same def, if both spans
5157 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5158 // been introduced by a item.
5159 let should_remove_import = duplicate && !has_dummy_span &&
5160 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5163 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5164 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5165 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5166 // Simple case - remove the entire import. Due to the above match arm, this can
5167 // only be a single use so just remove it entirely.
5168 err.tool_only_span_suggestion(
5169 directive.use_span_with_attributes,
5170 "remove unnecessary import",
5172 Applicability::MaybeIncorrect,
5175 Some((directive, span, _)) =>
5176 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5181 self.name_already_seen.insert(name, span);
5184 /// This function adds a suggestion to change the binding name of a new import that conflicts
5185 /// with an existing import.
5187 /// ```ignore (diagnostic)
5188 /// help: you can use `as` to change the binding name of the import
5190 /// LL | use foo::bar as other_bar;
5191 /// | ^^^^^^^^^^^^^^^^^^^^^
5193 fn add_suggestion_for_rename_of_use(
5195 err: &mut DiagnosticBuilder<'_>,
5197 directive: &ImportDirective<'_>,
5200 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5201 format!("Other{}", name)
5203 format!("other_{}", name)
5206 let mut suggestion = None;
5207 match directive.subclass {
5208 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5209 suggestion = Some(format!("self as {}", suggested_name)),
5210 ImportDirectiveSubclass::SingleImport { source, .. } => {
5211 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5212 .map(|pos| pos as usize) {
5213 if let Ok(snippet) = self.session.source_map()
5214 .span_to_snippet(binding_span) {
5215 if pos <= snippet.len() {
5216 suggestion = Some(format!(
5220 if snippet.ends_with(";") { ";" } else { "" }
5226 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5227 suggestion = Some(format!(
5228 "extern crate {} as {};",
5229 source.unwrap_or(target.name),
5232 _ => unreachable!(),
5235 let rename_msg = "you can use `as` to change the binding name of the import";
5236 if let Some(suggestion) = suggestion {
5237 err.span_suggestion(
5241 Applicability::MaybeIncorrect,
5244 err.span_label(binding_span, rename_msg);
5248 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5249 /// nested. In the following example, this function will be invoked to remove the `a` binding
5250 /// in the second use statement:
5252 /// ```ignore (diagnostic)
5253 /// use issue_52891::a;
5254 /// use issue_52891::{d, a, e};
5257 /// The following suggestion will be added:
5259 /// ```ignore (diagnostic)
5260 /// use issue_52891::{d, a, e};
5261 /// ^-- help: remove unnecessary import
5264 /// If the nested use contains only one import then the suggestion will remove the entire
5267 /// It is expected that the directive provided is a nested import - this isn't checked by the
5268 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5269 /// as characters expected by span manipulations won't be present.
5270 fn add_suggestion_for_duplicate_nested_use(
5272 err: &mut DiagnosticBuilder<'_>,
5273 directive: &ImportDirective<'_>,
5276 assert!(directive.is_nested());
5277 let message = "remove unnecessary import";
5279 // Two examples will be used to illustrate the span manipulations we're doing:
5281 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5282 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5283 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5284 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5286 let (found_closing_brace, span) = find_span_of_binding_until_next_binding(
5287 self.session, binding_span, directive.use_span,
5290 // If there was a closing brace then identify the span to remove any trailing commas from
5291 // previous imports.
5292 if found_closing_brace {
5293 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
5294 err.tool_only_span_suggestion(span, message, String::new(),
5295 Applicability::MaybeIncorrect);
5297 // Remove the entire line if we cannot extend the span back, this indicates a
5298 // `issue_52891::{self}` case.
5299 err.span_suggestion(directive.use_span_with_attributes, message, String::new(),
5300 Applicability::MaybeIncorrect);
5306 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5309 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5310 -> Option<&'a NameBinding<'a>> {
5311 if ident.is_path_segment_keyword() {
5312 // Make sure `self`, `super` etc produce an error when passed to here.
5315 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5316 if let Some(binding) = entry.extern_crate_item {
5317 if !speculative && entry.introduced_by_item {
5318 self.record_use(ident, TypeNS, binding, false);
5322 let crate_id = if !speculative {
5323 self.crate_loader.process_path_extern(ident.name, ident.span)
5324 } else if let Some(crate_id) =
5325 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5330 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5331 self.populate_module_if_necessary(&crate_root);
5332 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5333 .to_name_binding(self.arenas))
5339 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5340 namespace == TypeNS && path.len() == 1 && path[0].ident.name == kw::SelfUpper
5343 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5344 namespace == ValueNS && path.len() == 1 && path[0].ident.name == kw::SelfLower
5347 fn names_to_string(idents: &[Ident]) -> String {
5348 let mut result = String::new();
5349 for (i, ident) in idents.iter()
5350 .filter(|ident| ident.name != kw::PathRoot)
5353 result.push_str("::");
5355 result.push_str(&ident.as_str());
5360 fn path_names_to_string(path: &Path) -> String {
5361 names_to_string(&path.segments.iter()
5362 .map(|seg| seg.ident)
5363 .collect::<Vec<_>>())
5366 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5367 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5368 let variant_path = &suggestion.path;
5369 let variant_path_string = path_names_to_string(variant_path);
5371 let path_len = suggestion.path.segments.len();
5372 let enum_path = ast::Path {
5373 span: suggestion.path.span,
5374 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5376 let enum_path_string = path_names_to_string(&enum_path);
5378 (variant_path_string, enum_path_string)
5381 /// When an entity with a given name is not available in scope, we search for
5382 /// entities with that name in all crates. This method allows outputting the
5383 /// results of this search in a programmer-friendly way
5384 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5385 // This is `None` if all placement locations are inside expansions
5387 candidates: &[ImportSuggestion],
5391 // we want consistent results across executions, but candidates are produced
5392 // by iterating through a hash map, so make sure they are ordered:
5393 let mut path_strings: Vec<_> =
5394 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5395 path_strings.sort();
5397 let better = if better { "better " } else { "" };
5398 let msg_diff = match path_strings.len() {
5399 1 => " is found in another module, you can import it",
5400 _ => "s are found in other modules, you can import them",
5402 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5404 if let Some(span) = span {
5405 for candidate in &mut path_strings {
5406 // produce an additional newline to separate the new use statement
5407 // from the directly following item.
5408 let additional_newline = if found_use {
5413 *candidate = format!("use {};\n{}", candidate, additional_newline);
5416 err.span_suggestions(
5419 path_strings.into_iter(),
5420 Applicability::Unspecified,
5425 for candidate in path_strings {
5427 msg.push_str(&candidate);
5432 /// A somewhat inefficient routine to obtain the name of a module.
5433 fn module_to_string(module: Module<'_>) -> Option<String> {
5434 let mut names = Vec::new();
5436 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5437 if let ModuleKind::Def(.., name) = module.kind {
5438 if let Some(parent) = module.parent {
5439 names.push(Ident::with_empty_ctxt(name));
5440 collect_mod(names, parent);
5443 // danger, shouldn't be ident?
5444 names.push(Ident::from_str("<opaque>"));
5445 collect_mod(names, module.parent.unwrap());
5448 collect_mod(&mut names, module);
5450 if names.is_empty() {
5453 Some(names_to_string(&names.into_iter()
5455 .collect::<Vec<_>>()))
5458 #[derive(Copy, Clone, Debug)]
5460 /// Do not issue the lint.
5463 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5464 /// In this case, we can take the span of that path.
5467 /// This lint comes from a `use` statement. In this case, what we
5468 /// care about really is the *root* `use` statement; e.g., if we
5469 /// have nested things like `use a::{b, c}`, we care about the
5471 UsePath { root_id: NodeId, root_span: Span },
5473 /// This is the "trait item" from a fully qualified path. For example,
5474 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5475 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5476 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5480 fn node_id(&self) -> Option<NodeId> {
5482 CrateLint::No => None,
5483 CrateLint::SimplePath(id) |
5484 CrateLint::UsePath { root_id: id, .. } |
5485 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5490 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }