1 // ignore-tidy-filelength
3 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
5 #![feature(crate_visibility_modifier)]
6 #![feature(label_break_value)]
8 #![feature(rustc_diagnostic_macros)]
9 #![feature(type_alias_enum_variants)]
11 #![recursion_limit="256"]
13 #![deny(rust_2018_idioms)]
16 pub use rustc::hir::def::{Namespace, PerNS};
18 use GenericParameters::*;
20 use smallvec::smallvec;
22 use rustc::hir::map::{Definitions, DefCollector};
23 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
24 use rustc::middle::cstore::CrateStore;
25 use rustc::session::Session;
27 use rustc::hir::def::{
28 self, DefKind, PartialRes, CtorKind, CtorOf, NonMacroAttrKind, ExportMap
30 use rustc::hir::def::Namespace::*;
31 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
32 use rustc::hir::{TraitCandidate, TraitMap, GlobMap};
33 use rustc::ty::{self, DefIdTree};
34 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
35 use rustc::{bug, span_bug};
37 use rustc_metadata::creader::CrateLoader;
38 use rustc_metadata::cstore::CStore;
40 use syntax::source_map::SourceMap;
41 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
42 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
43 use syntax::ext::base::SyntaxExtension;
44 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
45 use syntax::ext::base::MacroKind;
46 use syntax::symbol::{Symbol, kw, sym};
47 use syntax::util::lev_distance::find_best_match_for_name;
49 use syntax::visit::{self, FnKind, Visitor};
51 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
52 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
53 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
54 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
55 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
57 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
59 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
60 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
64 use std::cell::{Cell, RefCell};
65 use std::{cmp, fmt, iter, mem, ptr};
66 use std::collections::BTreeSet;
67 use std::mem::replace;
68 use rustc_data_structures::ptr_key::PtrKey;
69 use rustc_data_structures::sync::Lrc;
70 use smallvec::SmallVec;
72 use diagnostics::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
73 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
74 use macros::{InvocationData, LegacyBinding, ParentScope};
76 type Res = def::Res<NodeId>;
78 // N.B., this module needs to be declared first so diagnostics are
79 // registered before they are used.
84 mod build_reduced_graph;
87 fn is_known_tool(name: Name) -> bool {
88 ["clippy", "rustfmt"].contains(&&*name.as_str())
98 AbsolutePath(Namespace),
103 /// A free importable items suggested in case of resolution failure.
104 struct ImportSuggestion {
109 /// A field or associated item from self type suggested in case of resolution failure.
110 enum AssocSuggestion {
117 struct BindingError {
119 origin: BTreeSet<Span>,
120 target: BTreeSet<Span>,
123 struct TypoSuggestion {
126 /// The kind of the binding ("crate", "module", etc.)
129 /// An appropriate article to refer to the binding ("a", "an", etc.)
130 article: &'static str,
133 impl PartialOrd for BindingError {
134 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
135 Some(self.cmp(other))
139 impl PartialEq for BindingError {
140 fn eq(&self, other: &BindingError) -> bool {
141 self.name == other.name
145 impl Ord for BindingError {
146 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
147 self.name.cmp(&other.name)
151 /// A vector of spans and replacements, a message and applicability.
152 type Suggestion = (Vec<(Span, String)>, String, Applicability);
154 enum ResolutionError<'a> {
155 /// Error E0401: can't use type or const parameters from outer function.
156 GenericParamsFromOuterFunction(Res),
157 /// Error E0403: the name is already used for a type or const parameter in this generic
159 NameAlreadyUsedInParameterList(Name, &'a Span),
160 /// Error E0407: method is not a member of trait.
161 MethodNotMemberOfTrait(Name, &'a str),
162 /// Error E0437: type is not a member of trait.
163 TypeNotMemberOfTrait(Name, &'a str),
164 /// Error E0438: const is not a member of trait.
165 ConstNotMemberOfTrait(Name, &'a str),
166 /// Error E0408: variable `{}` is not bound in all patterns.
167 VariableNotBoundInPattern(&'a BindingError),
168 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
169 VariableBoundWithDifferentMode(Name, Span),
170 /// Error E0415: identifier is bound more than once in this parameter list.
171 IdentifierBoundMoreThanOnceInParameterList(&'a str),
172 /// Error E0416: identifier is bound more than once in the same pattern.
173 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
174 /// Error E0426: use of undeclared label.
175 UndeclaredLabel(&'a str, Option<Name>),
176 /// Error E0429: `self` imports are only allowed within a `{ }` list.
177 SelfImportsOnlyAllowedWithin,
178 /// Error E0430: `self` import can only appear once in the list.
179 SelfImportCanOnlyAppearOnceInTheList,
180 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
181 SelfImportOnlyInImportListWithNonEmptyPrefix,
182 /// Error E0433: failed to resolve.
183 FailedToResolve { label: String, suggestion: Option<Suggestion> },
184 /// Error E0434: can't capture dynamic environment in a fn item.
185 CannotCaptureDynamicEnvironmentInFnItem,
186 /// Error E0435: attempt to use a non-constant value in a constant.
187 AttemptToUseNonConstantValueInConstant,
188 /// Error E0530: `X` bindings cannot shadow `Y`s.
189 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
190 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
191 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
192 /// Error E0671: const parameter cannot depend on type parameter.
193 ConstParamDependentOnTypeParam,
196 /// Combines an error with provided span and emits it.
198 /// This takes the error provided, combines it with the span and any additional spans inside the
199 /// error and emits it.
200 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
202 resolution_error: ResolutionError<'a>) {
203 resolve_struct_error(resolver, span, resolution_error).emit();
206 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
208 resolution_error: ResolutionError<'a>)
209 -> DiagnosticBuilder<'sess> {
210 match resolution_error {
211 ResolutionError::GenericParamsFromOuterFunction(outer_res) => {
212 let mut err = struct_span_err!(resolver.session,
215 "can't use generic parameters from outer function",
217 err.span_label(span, format!("use of generic parameter from outer function"));
219 let cm = resolver.session.source_map();
221 Res::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
222 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
223 resolver.definitions.opt_span(def_id)
226 reduce_impl_span_to_impl_keyword(cm, impl_span),
227 "`Self` type implicitly declared here, by this `impl`",
230 match (maybe_trait_defid, maybe_impl_defid) {
232 err.span_label(span, "can't use `Self` here");
235 err.span_label(span, "use a type here instead");
237 (None, None) => bug!("`impl` without trait nor type?"),
241 Res::Def(DefKind::TyParam, def_id) => {
242 if let Some(span) = resolver.definitions.opt_span(def_id) {
243 err.span_label(span, "type parameter from outer function");
246 Res::Def(DefKind::ConstParam, def_id) => {
247 if let Some(span) = resolver.definitions.opt_span(def_id) {
248 err.span_label(span, "const parameter from outer function");
252 bug!("GenericParamsFromOuterFunction should only be used with Res::SelfTy, \
257 // Try to retrieve the span of the function signature and generate a new message with
258 // a local type or const parameter.
259 let sugg_msg = &format!("try using a local generic parameter instead");
260 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
261 // Suggest the modification to the user
266 Applicability::MachineApplicable,
268 } else if let Some(sp) = cm.generate_fn_name_span(span) {
270 format!("try adding a local generic parameter in this method instead"));
272 err.help(&format!("try using a local generic parameter instead"));
277 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
278 let mut err = struct_span_err!(resolver.session,
281 "the name `{}` is already used for a generic \
282 parameter in this list of generic parameters",
284 err.span_label(span, "already used");
285 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
288 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
289 let mut err = struct_span_err!(resolver.session,
292 "method `{}` is not a member of trait `{}`",
295 err.span_label(span, format!("not a member of trait `{}`", trait_));
298 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
299 let mut err = struct_span_err!(resolver.session,
302 "type `{}` is not a member of trait `{}`",
305 err.span_label(span, format!("not a member of trait `{}`", trait_));
308 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
309 let mut err = struct_span_err!(resolver.session,
312 "const `{}` is not a member of trait `{}`",
315 err.span_label(span, format!("not a member of trait `{}`", trait_));
318 ResolutionError::VariableNotBoundInPattern(binding_error) => {
319 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
320 let msp = MultiSpan::from_spans(target_sp.clone());
321 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
322 let mut err = resolver.session.struct_span_err_with_code(
325 DiagnosticId::Error("E0408".into()),
327 for sp in target_sp {
328 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
330 let origin_sp = binding_error.origin.iter().cloned();
331 for sp in origin_sp {
332 err.span_label(sp, "variable not in all patterns");
336 ResolutionError::VariableBoundWithDifferentMode(variable_name,
337 first_binding_span) => {
338 let mut err = struct_span_err!(resolver.session,
341 "variable `{}` is bound in inconsistent \
342 ways within the same match arm",
344 err.span_label(span, "bound in different ways");
345 err.span_label(first_binding_span, "first binding");
348 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
349 let mut err = struct_span_err!(resolver.session,
352 "identifier `{}` is bound more than once in this parameter list",
354 err.span_label(span, "used as parameter more than once");
357 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
358 let mut err = struct_span_err!(resolver.session,
361 "identifier `{}` is bound more than once in the same pattern",
363 err.span_label(span, "used in a pattern more than once");
366 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
367 let mut err = struct_span_err!(resolver.session,
370 "use of undeclared label `{}`",
372 if let Some(lev_candidate) = lev_candidate {
375 "a label with a similar name exists in this scope",
376 lev_candidate.to_string(),
377 Applicability::MaybeIncorrect,
380 err.span_label(span, format!("undeclared label `{}`", name));
384 ResolutionError::SelfImportsOnlyAllowedWithin => {
385 struct_span_err!(resolver.session,
389 "`self` imports are only allowed within a { } list")
391 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
392 let mut err = struct_span_err!(resolver.session, span, E0430,
393 "`self` import can only appear once in an import list");
394 err.span_label(span, "can only appear once in an import list");
397 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
398 let mut err = struct_span_err!(resolver.session, span, E0431,
399 "`self` import can only appear in an import list with \
400 a non-empty prefix");
401 err.span_label(span, "can only appear in an import list with a non-empty prefix");
404 ResolutionError::FailedToResolve { label, suggestion } => {
405 let mut err = struct_span_err!(resolver.session, span, E0433,
406 "failed to resolve: {}", &label);
407 err.span_label(span, label);
409 if let Some((suggestions, msg, applicability)) = suggestion {
410 err.multipart_suggestion(&msg, suggestions, applicability);
415 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
416 let mut err = struct_span_err!(resolver.session,
420 "can't capture dynamic environment in a fn item");
421 err.help("use the `|| { ... }` closure form instead");
424 ResolutionError::AttemptToUseNonConstantValueInConstant => {
425 let mut err = struct_span_err!(resolver.session, span, E0435,
426 "attempt to use a non-constant value in a constant");
427 err.span_label(span, "non-constant value");
430 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
431 let shadows_what = binding.descr();
432 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
433 what_binding, shadows_what);
434 err.span_label(span, format!("cannot be named the same as {} {}",
435 binding.article(), shadows_what));
436 let participle = if binding.is_import() { "imported" } else { "defined" };
437 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
438 err.span_label(binding.span, msg);
441 ResolutionError::ForwardDeclaredTyParam => {
442 let mut err = struct_span_err!(resolver.session, span, E0128,
443 "type parameters with a default cannot use \
444 forward declared identifiers");
446 span, "defaulted type parameters cannot be forward declared".to_string());
449 ResolutionError::ConstParamDependentOnTypeParam => {
450 let mut err = struct_span_err!(
454 "const parameters cannot depend on type parameters"
456 err.span_label(span, format!("const parameter depends on type parameter"));
462 /// Adjust the impl span so that just the `impl` keyword is taken by removing
463 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
464 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
466 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
467 /// parser. If you need to use this function or something similar, please consider updating the
468 /// `source_map` functions and this function to something more robust.
469 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
470 let impl_span = cm.span_until_char(impl_span, '<');
471 let impl_span = cm.span_until_whitespace(impl_span);
475 #[derive(Copy, Clone, Debug)]
478 binding_mode: BindingMode,
481 /// Map from the name in a pattern to its binding mode.
482 type BindingMap = FxHashMap<Ident, BindingInfo>;
484 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
495 fn descr(self) -> &'static str {
497 PatternSource::Match => "match binding",
498 PatternSource::IfLet => "if let binding",
499 PatternSource::WhileLet => "while let binding",
500 PatternSource::Let => "let binding",
501 PatternSource::For => "for binding",
502 PatternSource::FnParam => "function parameter",
507 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
508 enum AliasPossibility {
513 #[derive(Copy, Clone, Debug)]
514 enum PathSource<'a> {
515 // Type paths `Path`.
517 // Trait paths in bounds or impls.
518 Trait(AliasPossibility),
519 // Expression paths `path`, with optional parent context.
520 Expr(Option<&'a Expr>),
521 // Paths in path patterns `Path`.
523 // Paths in struct expressions and patterns `Path { .. }`.
525 // Paths in tuple struct patterns `Path(..)`.
527 // `m::A::B` in `<T as m::A>::B::C`.
528 TraitItem(Namespace),
529 // Path in `pub(path)`
533 impl<'a> PathSource<'a> {
534 fn namespace(self) -> Namespace {
536 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
537 PathSource::Visibility => TypeNS,
538 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
539 PathSource::TraitItem(ns) => ns,
543 fn global_by_default(self) -> bool {
545 PathSource::Visibility => true,
546 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
547 PathSource::Struct | PathSource::TupleStruct |
548 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
552 fn defer_to_typeck(self) -> bool {
554 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
555 PathSource::Struct | PathSource::TupleStruct => true,
556 PathSource::Trait(_) | PathSource::TraitItem(..) |
557 PathSource::Visibility => false,
561 fn descr_expected(self) -> &'static str {
563 PathSource::Type => "type",
564 PathSource::Trait(_) => "trait",
565 PathSource::Pat => "unit struct/variant or constant",
566 PathSource::Struct => "struct, variant or union type",
567 PathSource::TupleStruct => "tuple struct/variant",
568 PathSource::Visibility => "module",
569 PathSource::TraitItem(ns) => match ns {
570 TypeNS => "associated type",
571 ValueNS => "method or associated constant",
572 MacroNS => bug!("associated macro"),
574 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
575 // "function" here means "anything callable" rather than `DefKind::Fn`,
576 // this is not precise but usually more helpful than just "value".
577 Some(&ExprKind::Call(..)) => "function",
583 fn is_expected(self, res: Res) -> bool {
585 PathSource::Type => match res {
586 Res::Def(DefKind::Struct, _)
587 | Res::Def(DefKind::Union, _)
588 | Res::Def(DefKind::Enum, _)
589 | Res::Def(DefKind::Trait, _)
590 | Res::Def(DefKind::TraitAlias, _)
591 | Res::Def(DefKind::TyAlias, _)
592 | Res::Def(DefKind::AssocTy, _)
594 | Res::Def(DefKind::TyParam, _)
596 | Res::Def(DefKind::Existential, _)
597 | Res::Def(DefKind::ForeignTy, _) => true,
600 PathSource::Trait(AliasPossibility::No) => match res {
601 Res::Def(DefKind::Trait, _) => true,
604 PathSource::Trait(AliasPossibility::Maybe) => match res {
605 Res::Def(DefKind::Trait, _) => true,
606 Res::Def(DefKind::TraitAlias, _) => true,
609 PathSource::Expr(..) => match res {
610 Res::Def(DefKind::Ctor(_, CtorKind::Const), _)
611 | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _)
612 | Res::Def(DefKind::Const, _)
613 | Res::Def(DefKind::Static, _)
615 | Res::Def(DefKind::Fn, _)
616 | Res::Def(DefKind::Method, _)
617 | Res::Def(DefKind::AssocConst, _)
619 | Res::Def(DefKind::ConstParam, _) => true,
622 PathSource::Pat => match res {
623 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
624 Res::Def(DefKind::Const, _) | Res::Def(DefKind::AssocConst, _) |
625 Res::SelfCtor(..) => true,
628 PathSource::TupleStruct => match res {
629 Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..) => true,
632 PathSource::Struct => match res {
633 Res::Def(DefKind::Struct, _)
634 | Res::Def(DefKind::Union, _)
635 | Res::Def(DefKind::Variant, _)
636 | Res::Def(DefKind::TyAlias, _)
637 | Res::Def(DefKind::AssocTy, _)
638 | Res::SelfTy(..) => true,
641 PathSource::TraitItem(ns) => match res {
642 Res::Def(DefKind::AssocConst, _)
643 | Res::Def(DefKind::Method, _) if ns == ValueNS => true,
644 Res::Def(DefKind::AssocTy, _) if ns == TypeNS => true,
647 PathSource::Visibility => match res {
648 Res::Def(DefKind::Mod, _) => true,
654 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
655 __diagnostic_used!(E0404);
656 __diagnostic_used!(E0405);
657 __diagnostic_used!(E0412);
658 __diagnostic_used!(E0422);
659 __diagnostic_used!(E0423);
660 __diagnostic_used!(E0425);
661 __diagnostic_used!(E0531);
662 __diagnostic_used!(E0532);
663 __diagnostic_used!(E0573);
664 __diagnostic_used!(E0574);
665 __diagnostic_used!(E0575);
666 __diagnostic_used!(E0576);
667 __diagnostic_used!(E0577);
668 __diagnostic_used!(E0578);
669 match (self, has_unexpected_resolution) {
670 (PathSource::Trait(_), true) => "E0404",
671 (PathSource::Trait(_), false) => "E0405",
672 (PathSource::Type, true) => "E0573",
673 (PathSource::Type, false) => "E0412",
674 (PathSource::Struct, true) => "E0574",
675 (PathSource::Struct, false) => "E0422",
676 (PathSource::Expr(..), true) => "E0423",
677 (PathSource::Expr(..), false) => "E0425",
678 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
679 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
680 (PathSource::TraitItem(..), true) => "E0575",
681 (PathSource::TraitItem(..), false) => "E0576",
682 (PathSource::Visibility, true) => "E0577",
683 (PathSource::Visibility, false) => "E0578",
688 // A minimal representation of a path segment. We use this in resolve because
689 // we synthesize 'path segments' which don't have the rest of an AST or HIR
691 #[derive(Clone, Copy, Debug)]
698 fn from_path(path: &Path) -> Vec<Segment> {
699 path.segments.iter().map(|s| s.into()).collect()
702 fn from_ident(ident: Ident) -> Segment {
709 fn names_to_string(segments: &[Segment]) -> String {
710 names_to_string(&segments.iter()
711 .map(|seg| seg.ident)
712 .collect::<Vec<_>>())
716 impl<'a> From<&'a ast::PathSegment> for Segment {
717 fn from(seg: &'a ast::PathSegment) -> Segment {
725 struct UsePlacementFinder {
726 target_module: NodeId,
731 impl UsePlacementFinder {
732 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
733 let mut finder = UsePlacementFinder {
738 visit::walk_crate(&mut finder, krate);
739 (finder.span, finder.found_use)
743 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
746 module: &'tcx ast::Mod,
748 _: &[ast::Attribute],
751 if self.span.is_some() {
754 if node_id != self.target_module {
755 visit::walk_mod(self, module);
758 // find a use statement
759 for item in &module.items {
761 ItemKind::Use(..) => {
762 // don't suggest placing a use before the prelude
763 // import or other generated ones
764 if item.span.ctxt().outer_expn_info().is_none() {
765 self.span = Some(item.span.shrink_to_lo());
766 self.found_use = true;
770 // don't place use before extern crate
771 ItemKind::ExternCrate(_) => {}
772 // but place them before the first other item
773 _ => if self.span.map_or(true, |span| item.span < span ) {
774 if item.span.ctxt().outer_expn_info().is_none() {
775 // don't insert between attributes and an item
776 if item.attrs.is_empty() {
777 self.span = Some(item.span.shrink_to_lo());
779 // find the first attribute on the item
780 for attr in &item.attrs {
781 if self.span.map_or(true, |span| attr.span < span) {
782 self.span = Some(attr.span.shrink_to_lo());
793 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
794 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
795 fn visit_item(&mut self, item: &'tcx Item) {
796 self.resolve_item(item);
798 fn visit_arm(&mut self, arm: &'tcx Arm) {
799 self.resolve_arm(arm);
801 fn visit_block(&mut self, block: &'tcx Block) {
802 self.resolve_block(block);
804 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
805 debug!("visit_anon_const {:?}", constant);
806 self.with_constant_rib(|this| {
807 visit::walk_anon_const(this, constant);
810 fn visit_expr(&mut self, expr: &'tcx Expr) {
811 self.resolve_expr(expr, None);
813 fn visit_local(&mut self, local: &'tcx Local) {
814 self.resolve_local(local);
816 fn visit_ty(&mut self, ty: &'tcx Ty) {
818 TyKind::Path(ref qself, ref path) => {
819 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
821 TyKind::ImplicitSelf => {
822 let self_ty = Ident::with_empty_ctxt(kw::SelfUpper);
823 let res = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
824 .map_or(Res::Err, |d| d.res());
825 self.record_partial_res(ty.id, PartialRes::new(res));
829 visit::walk_ty(self, ty);
831 fn visit_poly_trait_ref(&mut self,
832 tref: &'tcx ast::PolyTraitRef,
833 m: &'tcx ast::TraitBoundModifier) {
834 self.smart_resolve_path(tref.trait_ref.ref_id, None,
835 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
836 visit::walk_poly_trait_ref(self, tref, m);
838 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
839 let generic_params = match foreign_item.node {
840 ForeignItemKind::Fn(_, ref generics) => {
841 HasGenericParams(generics, ItemRibKind)
843 ForeignItemKind::Static(..) => NoGenericParams,
844 ForeignItemKind::Ty => NoGenericParams,
845 ForeignItemKind::Macro(..) => NoGenericParams,
847 self.with_generic_param_rib(generic_params, |this| {
848 visit::walk_foreign_item(this, foreign_item);
851 fn visit_fn(&mut self,
852 function_kind: FnKind<'tcx>,
853 declaration: &'tcx FnDecl,
857 debug!("(resolving function) entering function");
858 let (rib_kind, asyncness) = match function_kind {
859 FnKind::ItemFn(_, ref header, ..) =>
860 (FnItemRibKind, &header.asyncness.node),
861 FnKind::Method(_, ref sig, _, _) =>
862 (AssocItemRibKind, &sig.header.asyncness.node),
863 FnKind::Closure(_) =>
864 // Async closures aren't resolved through `visit_fn`-- they're
865 // processed separately
866 (NormalRibKind, &IsAsync::NotAsync),
869 // Create a value rib for the function.
870 self.ribs[ValueNS].push(Rib::new(rib_kind));
872 // Create a label rib for the function.
873 self.label_ribs.push(Rib::new(rib_kind));
875 // Add each argument to the rib.
876 let mut bindings_list = FxHashMap::default();
877 let mut add_argument = |argument: &ast::Arg| {
878 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
879 self.visit_ty(&argument.ty);
880 debug!("(resolving function) recorded argument");
883 // Walk the generated async arguments if this is an `async fn`, otherwise walk the
885 if let IsAsync::Async { ref arguments, .. } = asyncness {
886 for (i, a) in arguments.iter().enumerate() {
887 if let Some(arg) = &a.arg {
890 add_argument(&declaration.inputs[i]);
894 for a in &declaration.inputs { add_argument(a); }
897 visit::walk_fn_ret_ty(self, &declaration.output);
899 // Resolve the function body, potentially inside the body of an async closure
900 match function_kind {
901 FnKind::ItemFn(.., body) | FnKind::Method(.., body) => {
902 if let IsAsync::Async { ref arguments, .. } = asyncness {
903 let mut body = body.clone();
904 // Insert the generated statements into the body before attempting to
906 for a in arguments.iter().rev() {
907 if let Some(pat_stmt) = a.pat_stmt.clone() {
908 body.stmts.insert(0, pat_stmt);
910 body.stmts.insert(0, a.move_stmt.clone());
912 self.visit_block(&body);
914 self.visit_block(body);
917 FnKind::Closure(body) => {
918 self.visit_expr(body);
922 debug!("(resolving function) leaving function");
924 self.label_ribs.pop();
925 self.ribs[ValueNS].pop();
928 fn visit_generics(&mut self, generics: &'tcx Generics) {
929 // For type parameter defaults, we have to ban access
930 // to following type parameters, as the InternalSubsts can only
931 // provide previous type parameters as they're built. We
932 // put all the parameters on the ban list and then remove
933 // them one by one as they are processed and become available.
934 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
935 let mut found_default = false;
936 default_ban_rib.bindings.extend(generics.params.iter()
937 .filter_map(|param| match param.kind {
938 GenericParamKind::Const { .. } |
939 GenericParamKind::Lifetime { .. } => None,
940 GenericParamKind::Type { ref default, .. } => {
941 found_default |= default.is_some();
943 Some((Ident::with_empty_ctxt(param.ident.name), Res::Err))
950 // We also ban access to type parameters for use as the types of const parameters.
951 let mut const_ty_param_ban_rib = Rib::new(TyParamAsConstParamTy);
952 const_ty_param_ban_rib.bindings.extend(generics.params.iter()
954 if let GenericParamKind::Type { .. } = param.kind {
960 .map(|param| (Ident::with_empty_ctxt(param.ident.name), Res::Err)));
962 for param in &generics.params {
964 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
965 GenericParamKind::Type { ref default, .. } => {
966 for bound in ¶m.bounds {
967 self.visit_param_bound(bound);
970 if let Some(ref ty) = default {
971 self.ribs[TypeNS].push(default_ban_rib);
973 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
976 // Allow all following defaults to refer to this type parameter.
977 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
979 GenericParamKind::Const { ref ty } => {
980 self.ribs[TypeNS].push(const_ty_param_ban_rib);
982 for bound in ¶m.bounds {
983 self.visit_param_bound(bound);
988 const_ty_param_ban_rib = self.ribs[TypeNS].pop().unwrap();
992 for p in &generics.where_clause.predicates {
993 self.visit_where_predicate(p);
998 #[derive(Copy, Clone)]
999 enum GenericParameters<'a, 'b> {
1001 HasGenericParams(// Type parameters.
1004 // The kind of the rib used for type parameters.
1008 /// The rib kind restricts certain accesses,
1009 /// e.g. to a `Res::Local` of an outer item.
1010 #[derive(Copy, Clone, Debug)]
1012 /// No restriction needs to be applied.
1015 /// We passed through an impl or trait and are now in one of its
1016 /// methods or associated types. Allow references to ty params that impl or trait
1017 /// binds. Disallow any other upvars (including other ty params that are
1021 /// We passed through a function definition. Disallow upvars.
1022 /// Permit only those const parameters that are specified in the function's generics.
1025 /// We passed through an item scope. Disallow upvars.
1028 /// We're in a constant item. Can't refer to dynamic stuff.
1029 ConstantItemRibKind,
1031 /// We passed through a module.
1032 ModuleRibKind(Module<'a>),
1034 /// We passed through a `macro_rules!` statement
1035 MacroDefinition(DefId),
1037 /// All bindings in this rib are type parameters that can't be used
1038 /// from the default of a type parameter because they're not declared
1039 /// before said type parameter. Also see the `visit_generics` override.
1040 ForwardTyParamBanRibKind,
1042 /// We forbid the use of type parameters as the types of const parameters.
1043 TyParamAsConstParamTy,
1046 /// A single local scope.
1048 /// A rib represents a scope names can live in. Note that these appear in many places, not just
1049 /// around braces. At any place where the list of accessible names (of the given namespace)
1050 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
1051 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
1054 /// Different [rib kinds](enum.RibKind) are transparent for different names.
1056 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
1057 /// resolving, the name is looked up from inside out.
1059 struct Rib<'a, R = Res> {
1060 bindings: FxHashMap<Ident, R>,
1064 impl<'a, R> Rib<'a, R> {
1065 fn new(kind: RibKind<'a>) -> Rib<'a, R> {
1067 bindings: Default::default(),
1073 /// An intermediate resolution result.
1075 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
1076 /// items are visible in their whole block, while `Res`es only from the place they are defined
1078 enum LexicalScopeBinding<'a> {
1079 Item(&'a NameBinding<'a>),
1083 impl<'a> LexicalScopeBinding<'a> {
1084 fn item(self) -> Option<&'a NameBinding<'a>> {
1086 LexicalScopeBinding::Item(binding) => Some(binding),
1091 fn res(self) -> Res {
1093 LexicalScopeBinding::Item(binding) => binding.res(),
1094 LexicalScopeBinding::Res(res) => res,
1099 #[derive(Copy, Clone, Debug)]
1100 enum ModuleOrUniformRoot<'a> {
1104 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1105 CrateRootAndExternPrelude,
1107 /// Virtual module that denotes resolution in extern prelude.
1108 /// Used for paths starting with `::` on 2018 edition.
1111 /// Virtual module that denotes resolution in current scope.
1112 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1113 /// are always split into two parts, the first of which should be some kind of module.
1117 impl ModuleOrUniformRoot<'_> {
1118 fn same_def(lhs: Self, rhs: Self) -> bool {
1120 (ModuleOrUniformRoot::Module(lhs),
1121 ModuleOrUniformRoot::Module(rhs)) => lhs.def_id() == rhs.def_id(),
1122 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1123 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1124 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1125 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1131 #[derive(Clone, Debug)]
1132 enum PathResult<'a> {
1133 Module(ModuleOrUniformRoot<'a>),
1134 NonModule(PartialRes),
1139 suggestion: Option<Suggestion>,
1140 is_error_from_last_segment: bool,
1145 /// An anonymous module; e.g., just a block.
1149 /// fn f() {} // (1)
1150 /// { // This is an anonymous module
1151 /// f(); // This resolves to (2) as we are inside the block.
1152 /// fn f() {} // (2)
1154 /// f(); // Resolves to (1)
1158 /// Any module with a name.
1162 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1163 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1165 Def(DefKind, DefId, Name),
1169 /// Get name of the module.
1170 pub fn name(&self) -> Option<Name> {
1172 ModuleKind::Block(..) => None,
1173 ModuleKind::Def(.., name) => Some(*name),
1178 /// One node in the tree of modules.
1179 pub struct ModuleData<'a> {
1180 parent: Option<Module<'a>>,
1183 // The def id of the closest normal module (`mod`) ancestor (including this module).
1184 normal_ancestor_id: DefId,
1186 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1187 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1188 Option<&'a NameBinding<'a>>)>>,
1189 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1191 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1193 // Macro invocations that can expand into items in this module.
1194 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1196 no_implicit_prelude: bool,
1198 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1199 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1201 // Used to memoize the traits in this module for faster searches through all traits in scope.
1202 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1204 // Whether this module is populated. If not populated, any attempt to
1205 // access the children must be preceded with a
1206 // `populate_module_if_necessary` call.
1207 populated: Cell<bool>,
1209 /// Span of the module itself. Used for error reporting.
1215 type Module<'a> = &'a ModuleData<'a>;
1217 impl<'a> ModuleData<'a> {
1218 fn new(parent: Option<Module<'a>>,
1220 normal_ancestor_id: DefId,
1222 span: Span) -> Self {
1227 resolutions: Default::default(),
1228 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1229 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1230 builtin_attrs: RefCell::new(Vec::new()),
1231 unresolved_invocations: Default::default(),
1232 no_implicit_prelude: false,
1233 glob_importers: RefCell::new(Vec::new()),
1234 globs: RefCell::new(Vec::new()),
1235 traits: RefCell::new(None),
1236 populated: Cell::new(normal_ancestor_id.is_local()),
1242 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1243 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1244 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1248 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1249 let resolutions = self.resolutions.borrow();
1250 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1251 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1252 for &(&(ident, ns), &resolution) in resolutions.iter() {
1253 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1257 fn res(&self) -> Option<Res> {
1259 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
1264 fn def_kind(&self) -> Option<DefKind> {
1266 ModuleKind::Def(kind, ..) => Some(kind),
1271 fn def_id(&self) -> Option<DefId> {
1273 ModuleKind::Def(_, def_id, _) => Some(def_id),
1278 // `self` resolves to the first module ancestor that `is_normal`.
1279 fn is_normal(&self) -> bool {
1281 ModuleKind::Def(DefKind::Mod, _, _) => true,
1286 fn is_trait(&self) -> bool {
1288 ModuleKind::Def(DefKind::Trait, _, _) => true,
1293 fn nearest_item_scope(&'a self) -> Module<'a> {
1294 if self.is_trait() { self.parent.unwrap() } else { self }
1297 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1298 while !ptr::eq(self, other) {
1299 if let Some(parent) = other.parent {
1309 impl<'a> fmt::Debug for ModuleData<'a> {
1310 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1311 write!(f, "{:?}", self.res())
1315 /// Records a possibly-private value, type, or module definition.
1316 #[derive(Clone, Debug)]
1317 pub struct NameBinding<'a> {
1318 kind: NameBindingKind<'a>,
1319 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1322 vis: ty::Visibility,
1325 pub trait ToNameBinding<'a> {
1326 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1329 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1330 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1335 #[derive(Clone, Debug)]
1336 enum NameBindingKind<'a> {
1337 Res(Res, /* is_macro_export */ bool),
1340 binding: &'a NameBinding<'a>,
1341 directive: &'a ImportDirective<'a>,
1346 impl<'a> NameBindingKind<'a> {
1347 /// Is this a name binding of a import?
1348 fn is_import(&self) -> bool {
1350 NameBindingKind::Import { .. } => true,
1356 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1358 struct UseError<'a> {
1359 err: DiagnosticBuilder<'a>,
1360 /// Attach `use` statements for these candidates.
1361 candidates: Vec<ImportSuggestion>,
1362 /// The `NodeId` of the module to place the use-statements in.
1364 /// Whether the diagnostic should state that it's "better".
1368 #[derive(Clone, Copy, PartialEq, Debug)]
1369 enum AmbiguityKind {
1373 LegacyHelperVsPrelude,
1378 MoreExpandedVsOuter,
1381 impl AmbiguityKind {
1382 fn descr(self) -> &'static str {
1384 AmbiguityKind::Import =>
1385 "name vs any other name during import resolution",
1386 AmbiguityKind::BuiltinAttr =>
1387 "built-in attribute vs any other name",
1388 AmbiguityKind::DeriveHelper =>
1389 "derive helper attribute vs any other name",
1390 AmbiguityKind::LegacyHelperVsPrelude =>
1391 "legacy plugin helper attribute vs name from prelude",
1392 AmbiguityKind::LegacyVsModern =>
1393 "`macro_rules` vs non-`macro_rules` from other module",
1394 AmbiguityKind::GlobVsOuter =>
1395 "glob import vs any other name from outer scope during import/macro resolution",
1396 AmbiguityKind::GlobVsGlob =>
1397 "glob import vs glob import in the same module",
1398 AmbiguityKind::GlobVsExpanded =>
1399 "glob import vs macro-expanded name in the same \
1400 module during import/macro resolution",
1401 AmbiguityKind::MoreExpandedVsOuter =>
1402 "macro-expanded name vs less macro-expanded name \
1403 from outer scope during import/macro resolution",
1408 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1409 #[derive(Clone, Copy, PartialEq)]
1410 enum AmbiguityErrorMisc {
1417 struct AmbiguityError<'a> {
1418 kind: AmbiguityKind,
1420 b1: &'a NameBinding<'a>,
1421 b2: &'a NameBinding<'a>,
1422 misc1: AmbiguityErrorMisc,
1423 misc2: AmbiguityErrorMisc,
1426 impl<'a> NameBinding<'a> {
1427 fn module(&self) -> Option<Module<'a>> {
1429 NameBindingKind::Module(module) => Some(module),
1430 NameBindingKind::Import { binding, .. } => binding.module(),
1435 fn res(&self) -> Res {
1437 NameBindingKind::Res(res, _) => res,
1438 NameBindingKind::Module(module) => module.res().unwrap(),
1439 NameBindingKind::Import { binding, .. } => binding.res(),
1443 fn is_ambiguity(&self) -> bool {
1444 self.ambiguity.is_some() || match self.kind {
1445 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1450 // We sometimes need to treat variants as `pub` for backwards compatibility.
1451 fn pseudo_vis(&self) -> ty::Visibility {
1452 if self.is_variant() && self.res().def_id().is_local() {
1453 ty::Visibility::Public
1459 fn is_variant(&self) -> bool {
1461 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _) |
1462 NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
1467 fn is_extern_crate(&self) -> bool {
1469 NameBindingKind::Import {
1470 directive: &ImportDirective {
1471 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1474 NameBindingKind::Module(
1475 &ModuleData { kind: ModuleKind::Def(DefKind::Mod, def_id, _), .. }
1476 ) => def_id.index == CRATE_DEF_INDEX,
1481 fn is_import(&self) -> bool {
1483 NameBindingKind::Import { .. } => true,
1488 fn is_glob_import(&self) -> bool {
1490 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1495 fn is_importable(&self) -> bool {
1497 Res::Def(DefKind::AssocConst, _)
1498 | Res::Def(DefKind::Method, _)
1499 | Res::Def(DefKind::AssocTy, _) => false,
1504 fn is_macro_def(&self) -> bool {
1506 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
1511 fn macro_kind(&self) -> Option<MacroKind> {
1513 Res::Def(DefKind::Macro(kind), _) => Some(kind),
1514 Res::NonMacroAttr(..) => Some(MacroKind::Attr),
1519 fn descr(&self) -> &'static str {
1520 if self.is_extern_crate() { "extern crate" } else { self.res().descr() }
1523 fn article(&self) -> &'static str {
1524 if self.is_extern_crate() { "an" } else { self.res().article() }
1527 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1528 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1529 // Then this function returns `true` if `self` may emerge from a macro *after* that
1530 // in some later round and screw up our previously found resolution.
1531 // See more detailed explanation in
1532 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1533 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1534 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1535 // Expansions are partially ordered, so "may appear after" is an inversion of
1536 // "certainly appears before or simultaneously" and includes unordered cases.
1537 let self_parent_expansion = self.expansion;
1538 let other_parent_expansion = binding.expansion;
1539 let certainly_before_other_or_simultaneously =
1540 other_parent_expansion.is_descendant_of(self_parent_expansion);
1541 let certainly_before_invoc_or_simultaneously =
1542 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1543 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1547 /// Interns the names of the primitive types.
1549 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1550 /// special handling, since they have no place of origin.
1552 struct PrimitiveTypeTable {
1553 primitive_types: FxHashMap<Name, PrimTy>,
1556 impl PrimitiveTypeTable {
1557 fn new() -> PrimitiveTypeTable {
1558 let mut table = PrimitiveTypeTable::default();
1560 table.intern("bool", Bool);
1561 table.intern("char", Char);
1562 table.intern("f32", Float(FloatTy::F32));
1563 table.intern("f64", Float(FloatTy::F64));
1564 table.intern("isize", Int(IntTy::Isize));
1565 table.intern("i8", Int(IntTy::I8));
1566 table.intern("i16", Int(IntTy::I16));
1567 table.intern("i32", Int(IntTy::I32));
1568 table.intern("i64", Int(IntTy::I64));
1569 table.intern("i128", Int(IntTy::I128));
1570 table.intern("str", Str);
1571 table.intern("usize", Uint(UintTy::Usize));
1572 table.intern("u8", Uint(UintTy::U8));
1573 table.intern("u16", Uint(UintTy::U16));
1574 table.intern("u32", Uint(UintTy::U32));
1575 table.intern("u64", Uint(UintTy::U64));
1576 table.intern("u128", Uint(UintTy::U128));
1580 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1581 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1585 #[derive(Debug, Default, Clone)]
1586 pub struct ExternPreludeEntry<'a> {
1587 extern_crate_item: Option<&'a NameBinding<'a>>,
1588 pub introduced_by_item: bool,
1591 /// The main resolver class.
1593 /// This is the visitor that walks the whole crate.
1594 pub struct Resolver<'a> {
1595 session: &'a Session,
1598 pub definitions: Definitions,
1600 graph_root: Module<'a>,
1602 prelude: Option<Module<'a>>,
1603 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1605 /// N.B., this is used only for better diagnostics, not name resolution itself.
1606 has_self: FxHashSet<DefId>,
1608 /// Names of fields of an item `DefId` accessible with dot syntax.
1609 /// Used for hints during error reporting.
1610 field_names: FxHashMap<DefId, Vec<Name>>,
1612 /// All imports known to succeed or fail.
1613 determined_imports: Vec<&'a ImportDirective<'a>>,
1615 /// All non-determined imports.
1616 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1618 /// The module that represents the current item scope.
1619 current_module: Module<'a>,
1621 /// The current set of local scopes for types and values.
1622 /// FIXME #4948: Reuse ribs to avoid allocation.
1623 ribs: PerNS<Vec<Rib<'a>>>,
1625 /// The current set of local scopes, for labels.
1626 label_ribs: Vec<Rib<'a, NodeId>>,
1628 /// The trait that the current context can refer to.
1629 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1631 /// The current self type if inside an impl (used for better errors).
1632 current_self_type: Option<Ty>,
1634 /// The current self item if inside an ADT (used for better errors).
1635 current_self_item: Option<NodeId>,
1637 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1638 /// We are resolving a last import segment during import validation.
1639 last_import_segment: bool,
1640 /// This binding should be ignored during in-module resolution, so that we don't get
1641 /// "self-confirming" import resolutions during import validation.
1642 blacklisted_binding: Option<&'a NameBinding<'a>>,
1644 /// The idents for the primitive types.
1645 primitive_type_table: PrimitiveTypeTable,
1647 /// Resolutions for nodes that have a single resolution.
1648 partial_res_map: NodeMap<PartialRes>,
1649 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
1650 import_res_map: NodeMap<PerNS<Option<Res>>>,
1651 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
1652 label_res_map: NodeMap<NodeId>,
1654 pub export_map: ExportMap<NodeId>,
1655 pub trait_map: TraitMap,
1657 /// A map from nodes to anonymous modules.
1658 /// Anonymous modules are pseudo-modules that are implicitly created around items
1659 /// contained within blocks.
1661 /// For example, if we have this:
1669 /// There will be an anonymous module created around `g` with the ID of the
1670 /// entry block for `f`.
1671 block_map: NodeMap<Module<'a>>,
1672 module_map: FxHashMap<DefId, Module<'a>>,
1673 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1674 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1676 /// Maps glob imports to the names of items actually imported.
1677 pub glob_map: GlobMap,
1679 used_imports: FxHashSet<(NodeId, Namespace)>,
1680 pub maybe_unused_trait_imports: NodeSet,
1681 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1683 /// A list of labels as of yet unused. Labels will be removed from this map when
1684 /// they are used (in a `break` or `continue` statement)
1685 pub unused_labels: FxHashMap<NodeId, Span>,
1687 /// Privacy errors are delayed until the end in order to deduplicate them.
1688 privacy_errors: Vec<PrivacyError<'a>>,
1689 /// Ambiguity errors are delayed for deduplication.
1690 ambiguity_errors: Vec<AmbiguityError<'a>>,
1691 /// `use` injections are delayed for better placement and deduplication.
1692 use_injections: Vec<UseError<'a>>,
1693 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1694 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1696 arenas: &'a ResolverArenas<'a>,
1697 dummy_binding: &'a NameBinding<'a>,
1699 crate_loader: &'a mut CrateLoader<'a>,
1700 macro_names: FxHashSet<Ident>,
1701 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1702 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1703 pub all_macros: FxHashMap<Name, Res>,
1704 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1705 macro_defs: FxHashMap<Mark, DefId>,
1706 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1708 /// List of crate local macros that we need to warn about as being unused.
1709 /// Right now this only includes macro_rules! macros, and macros 2.0.
1710 unused_macros: FxHashSet<DefId>,
1712 /// Maps the `Mark` of an expansion to its containing module or block.
1713 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1715 /// Avoid duplicated errors for "name already defined".
1716 name_already_seen: FxHashMap<Name, Span>,
1718 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1720 /// Table for mapping struct IDs into struct constructor IDs,
1721 /// it's not used during normal resolution, only for better error reporting.
1722 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
1724 /// Only used for better errors on `fn(): fn()`.
1725 current_type_ascription: Vec<Span>,
1727 injected_crate: Option<Module<'a>>,
1730 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1732 pub struct ResolverArenas<'a> {
1733 modules: arena::TypedArena<ModuleData<'a>>,
1734 local_modules: RefCell<Vec<Module<'a>>>,
1735 name_bindings: arena::TypedArena<NameBinding<'a>>,
1736 import_directives: arena::TypedArena<ImportDirective<'a>>,
1737 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1738 invocation_data: arena::TypedArena<InvocationData<'a>>,
1739 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1742 impl<'a> ResolverArenas<'a> {
1743 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1744 let module = self.modules.alloc(module);
1745 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1746 self.local_modules.borrow_mut().push(module);
1750 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1751 self.local_modules.borrow()
1753 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1754 self.name_bindings.alloc(name_binding)
1756 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1757 -> &'a ImportDirective<'_> {
1758 self.import_directives.alloc(import_directive)
1760 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1761 self.name_resolutions.alloc(Default::default())
1763 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1764 -> &'a InvocationData<'a> {
1765 self.invocation_data.alloc(expansion_data)
1767 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1768 self.legacy_bindings.alloc(binding)
1772 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1773 fn parent(self, id: DefId) -> Option<DefId> {
1775 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1776 _ => self.cstore.def_key(id).parent,
1777 }.map(|index| DefId { index, ..id })
1781 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1782 /// the resolver is no longer needed as all the relevant information is inline.
1783 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1784 fn resolve_hir_path(
1789 self.resolve_hir_path_cb(path, is_value,
1790 |resolver, span, error| resolve_error(resolver, span, error))
1793 fn resolve_str_path(
1796 crate_root: Option<Symbol>,
1797 components: &[Symbol],
1800 let root = if crate_root.is_some() {
1805 let segments = iter::once(Ident::with_empty_ctxt(root))
1807 crate_root.into_iter()
1808 .chain(components.iter().cloned())
1809 .map(Ident::with_empty_ctxt)
1810 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1812 let path = ast::Path {
1817 self.resolve_hir_path(&path, is_value)
1820 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1821 self.partial_res_map.get(&id).cloned()
1824 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1825 self.import_res_map.get(&id).cloned().unwrap_or_default()
1828 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1829 self.label_res_map.get(&id).cloned()
1832 fn definitions(&mut self) -> &mut Definitions {
1833 &mut self.definitions
1837 impl<'a> Resolver<'a> {
1838 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1839 /// isn't something that can be returned because it can't be made to live that long,
1840 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1841 /// just that an error occurred.
1842 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1843 -> Result<hir::Path, ()> {
1844 let mut errored = false;
1846 let path = if path_str.starts_with("::") {
1849 segments: iter::once(Ident::with_empty_ctxt(kw::PathRoot))
1851 path_str.split("::").skip(1).map(Ident::from_str)
1853 .map(|i| self.new_ast_path_segment(i))
1861 .map(Ident::from_str)
1862 .map(|i| self.new_ast_path_segment(i))
1866 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1867 if errored || path.res == def::Res::Err {
1874 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1875 fn resolve_hir_path_cb<F>(
1881 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1883 let namespace = if is_value { ValueNS } else { TypeNS };
1884 let span = path.span;
1885 let segments = &path.segments;
1886 let path = Segment::from_path(&path);
1887 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1888 let res = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1889 span, CrateLint::No) {
1890 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1891 module.res().unwrap(),
1892 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1893 path_res.base_res(),
1894 PathResult::NonModule(..) => {
1895 error_callback(self, span, ResolutionError::FailedToResolve {
1896 label: String::from("type-relative paths are not supported in this context"),
1901 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1902 PathResult::Failed { span, label, suggestion, .. } => {
1903 error_callback(self, span, ResolutionError::FailedToResolve {
1911 let segments: Vec<_> = segments.iter().map(|seg| {
1912 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1913 hir_seg.res = Some(self.partial_res_map.get(&seg.id).map_or(def::Res::Err, |p| {
1914 p.base_res().map_id(|_| panic!("unexpected node_id"))
1920 res: res.map_id(|_| panic!("unexpected node_id")),
1921 segments: segments.into(),
1925 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1926 let mut seg = ast::PathSegment::from_ident(ident);
1927 seg.id = self.session.next_node_id();
1932 impl<'a> Resolver<'a> {
1933 pub fn new(session: &'a Session,
1937 crate_loader: &'a mut CrateLoader<'a>,
1938 arenas: &'a ResolverArenas<'a>)
1940 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1941 let root_module_kind = ModuleKind::Def(
1946 let graph_root = arenas.alloc_module(ModuleData {
1947 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1948 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1950 let mut module_map = FxHashMap::default();
1951 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1953 let mut definitions = Definitions::default();
1954 DefCollector::new(&mut definitions, Mark::root())
1955 .collect_root(crate_name, session.local_crate_disambiguator());
1957 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1958 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1961 if !attr::contains_name(&krate.attrs, sym::no_core) {
1962 extern_prelude.insert(Ident::with_empty_ctxt(sym::core), Default::default());
1963 if !attr::contains_name(&krate.attrs, sym::no_std) {
1964 extern_prelude.insert(Ident::with_empty_ctxt(sym::std), Default::default());
1965 if session.rust_2018() {
1966 extern_prelude.insert(Ident::with_empty_ctxt(sym::meta), Default::default());
1971 let mut invocations = FxHashMap::default();
1972 invocations.insert(Mark::root(),
1973 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1975 let mut macro_defs = FxHashMap::default();
1976 macro_defs.insert(Mark::root(), root_def_id);
1985 // The outermost module has def ID 0; this is not reflected in the
1991 has_self: FxHashSet::default(),
1992 field_names: FxHashMap::default(),
1994 determined_imports: Vec::new(),
1995 indeterminate_imports: Vec::new(),
1997 current_module: graph_root,
1999 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2000 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2001 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
2003 label_ribs: Vec::new(),
2005 current_trait_ref: None,
2006 current_self_type: None,
2007 current_self_item: None,
2008 last_import_segment: false,
2009 blacklisted_binding: None,
2011 primitive_type_table: PrimitiveTypeTable::new(),
2013 partial_res_map: Default::default(),
2014 import_res_map: Default::default(),
2015 label_res_map: Default::default(),
2016 export_map: FxHashMap::default(),
2017 trait_map: Default::default(),
2019 block_map: Default::default(),
2020 extern_module_map: FxHashMap::default(),
2021 binding_parent_modules: FxHashMap::default(),
2023 glob_map: Default::default(),
2025 used_imports: FxHashSet::default(),
2026 maybe_unused_trait_imports: Default::default(),
2027 maybe_unused_extern_crates: Vec::new(),
2029 unused_labels: FxHashMap::default(),
2031 privacy_errors: Vec::new(),
2032 ambiguity_errors: Vec::new(),
2033 use_injections: Vec::new(),
2034 macro_expanded_macro_export_errors: BTreeSet::new(),
2037 dummy_binding: arenas.alloc_name_binding(NameBinding {
2038 kind: NameBindingKind::Res(Res::Err, false),
2040 expansion: Mark::root(),
2042 vis: ty::Visibility::Public,
2046 macro_names: FxHashSet::default(),
2047 builtin_macros: FxHashMap::default(),
2048 macro_use_prelude: FxHashMap::default(),
2049 all_macros: FxHashMap::default(),
2050 macro_map: FxHashMap::default(),
2053 local_macro_def_scopes: FxHashMap::default(),
2054 name_already_seen: FxHashMap::default(),
2055 potentially_unused_imports: Vec::new(),
2056 struct_constructors: Default::default(),
2057 unused_macros: FxHashSet::default(),
2058 current_type_ascription: Vec::new(),
2059 injected_crate: None,
2063 pub fn arenas() -> ResolverArenas<'a> {
2067 /// Runs the function on each namespace.
2068 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
2074 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
2076 match self.macro_defs.get(&ctxt.outer()) {
2077 Some(&def_id) => return def_id,
2078 None => ctxt.remove_mark(),
2083 /// Entry point to crate resolution.
2084 pub fn resolve_crate(&mut self, krate: &Crate) {
2085 ImportResolver { resolver: self }.finalize_imports();
2086 self.current_module = self.graph_root;
2087 self.finalize_current_module_macro_resolutions();
2089 visit::walk_crate(self, krate);
2091 check_unused::check_crate(self, krate);
2092 self.report_errors(krate);
2093 self.crate_loader.postprocess(krate);
2100 normal_ancestor_id: DefId,
2104 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
2105 self.arenas.alloc_module(module)
2108 fn record_use(&mut self, ident: Ident, ns: Namespace,
2109 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
2110 if let Some((b2, kind)) = used_binding.ambiguity {
2111 self.ambiguity_errors.push(AmbiguityError {
2112 kind, ident, b1: used_binding, b2,
2113 misc1: AmbiguityErrorMisc::None,
2114 misc2: AmbiguityErrorMisc::None,
2117 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
2118 // Avoid marking `extern crate` items that refer to a name from extern prelude,
2119 // but not introduce it, as used if they are accessed from lexical scope.
2120 if is_lexical_scope {
2121 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
2122 if let Some(crate_item) = entry.extern_crate_item {
2123 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2130 directive.used.set(true);
2131 self.used_imports.insert((directive.id, ns));
2132 self.add_to_glob_map(&directive, ident);
2133 self.record_use(ident, ns, binding, false);
2138 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2139 if directive.is_glob() {
2140 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2144 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2145 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2146 /// `ident` in the first scope that defines it (or None if no scopes define it).
2148 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2149 /// the items are defined in the block. For example,
2152 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2155 /// g(); // This resolves to the local variable `g` since it shadows the item.
2159 /// Invariant: This must only be called during main resolution, not during
2160 /// import resolution.
2161 fn resolve_ident_in_lexical_scope(&mut self,
2164 record_used_id: Option<NodeId>,
2166 -> Option<LexicalScopeBinding<'a>> {
2167 assert!(ns == TypeNS || ns == ValueNS);
2168 if ident.name == kw::Invalid {
2169 return Some(LexicalScopeBinding::Res(Res::Err));
2171 ident.span = if ident.name == kw::SelfUpper {
2172 // FIXME(jseyfried) improve `Self` hygiene
2173 ident.span.with_ctxt(SyntaxContext::empty())
2174 } else if ns == TypeNS {
2177 ident.span.modern_and_legacy()
2180 // Walk backwards up the ribs in scope.
2181 let record_used = record_used_id.is_some();
2182 let mut module = self.graph_root;
2183 for i in (0 .. self.ribs[ns].len()).rev() {
2184 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2185 if let Some(res) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2186 // The ident resolves to a type parameter or local variable.
2187 return Some(LexicalScopeBinding::Res(
2188 self.validate_res_from_ribs(ns, i, res, record_used, path_span),
2192 module = match self.ribs[ns][i].kind {
2193 ModuleRibKind(module) => module,
2194 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2195 // If an invocation of this macro created `ident`, give up on `ident`
2196 // and switch to `ident`'s source from the macro definition.
2197 ident.span.remove_mark();
2203 let item = self.resolve_ident_in_module_unadjusted(
2204 ModuleOrUniformRoot::Module(module),
2210 if let Ok(binding) = item {
2211 // The ident resolves to an item.
2212 return Some(LexicalScopeBinding::Item(binding));
2216 ModuleKind::Block(..) => {}, // We can see through blocks
2221 ident.span = ident.span.modern();
2222 let mut poisoned = None;
2224 let opt_module = if let Some(node_id) = record_used_id {
2225 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2226 node_id, &mut poisoned)
2228 self.hygienic_lexical_parent(module, &mut ident.span)
2230 module = unwrap_or!(opt_module, break);
2231 let orig_current_module = self.current_module;
2232 self.current_module = module; // Lexical resolutions can never be a privacy error.
2233 let result = self.resolve_ident_in_module_unadjusted(
2234 ModuleOrUniformRoot::Module(module),
2240 self.current_module = orig_current_module;
2244 if let Some(node_id) = poisoned {
2245 self.session.buffer_lint_with_diagnostic(
2246 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2247 node_id, ident.span,
2248 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2249 lint::builtin::BuiltinLintDiagnostics::
2250 ProcMacroDeriveResolutionFallback(ident.span),
2253 return Some(LexicalScopeBinding::Item(binding))
2255 Err(Determined) => continue,
2256 Err(Undetermined) =>
2257 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2261 if !module.no_implicit_prelude {
2263 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2264 return Some(LexicalScopeBinding::Item(binding));
2267 if ns == TypeNS && is_known_tool(ident.name) {
2268 let binding = (Res::ToolMod, ty::Visibility::Public,
2269 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2270 return Some(LexicalScopeBinding::Item(binding));
2272 if let Some(prelude) = self.prelude {
2273 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2274 ModuleOrUniformRoot::Module(prelude),
2280 return Some(LexicalScopeBinding::Item(binding));
2288 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2289 -> Option<Module<'a>> {
2290 if !module.expansion.outer_is_descendant_of(span.ctxt()) {
2291 return Some(self.macro_def_scope(span.remove_mark()));
2294 if let ModuleKind::Block(..) = module.kind {
2295 return Some(module.parent.unwrap());
2301 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2302 span: &mut Span, node_id: NodeId,
2303 poisoned: &mut Option<NodeId>)
2304 -> Option<Module<'a>> {
2305 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2309 // We need to support the next case under a deprecation warning
2312 // ---- begin: this comes from a proc macro derive
2313 // mod implementation_details {
2314 // // Note that `MyStruct` is not in scope here.
2315 // impl SomeTrait for MyStruct { ... }
2319 // So we have to fall back to the module's parent during lexical resolution in this case.
2320 if let Some(parent) = module.parent {
2321 // Inner module is inside the macro, parent module is outside of the macro.
2322 if module.expansion != parent.expansion &&
2323 module.expansion.is_descendant_of(parent.expansion) {
2324 // The macro is a proc macro derive
2325 if module.expansion.looks_like_proc_macro_derive() {
2326 if parent.expansion.outer_is_descendant_of(span.ctxt()) {
2327 *poisoned = Some(node_id);
2328 return module.parent;
2337 fn resolve_ident_in_module(
2339 module: ModuleOrUniformRoot<'a>,
2342 parent_scope: Option<&ParentScope<'a>>,
2345 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2346 self.resolve_ident_in_module_ext(
2347 module, ident, ns, parent_scope, record_used, path_span
2348 ).map_err(|(determinacy, _)| determinacy)
2351 fn resolve_ident_in_module_ext(
2353 module: ModuleOrUniformRoot<'a>,
2356 parent_scope: Option<&ParentScope<'a>>,
2359 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2360 let orig_current_module = self.current_module;
2362 ModuleOrUniformRoot::Module(module) => {
2363 ident.span = ident.span.modern();
2364 if let Some(def) = ident.span.adjust(module.expansion) {
2365 self.current_module = self.macro_def_scope(def);
2368 ModuleOrUniformRoot::ExternPrelude => {
2369 ident.span = ident.span.modern();
2370 ident.span.adjust(Mark::root());
2372 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2373 ModuleOrUniformRoot::CurrentScope => {
2377 let result = self.resolve_ident_in_module_unadjusted_ext(
2378 module, ident, ns, parent_scope, false, record_used, path_span,
2380 self.current_module = orig_current_module;
2384 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2385 let mut ctxt = ident.span.ctxt();
2386 let mark = if ident.name == kw::DollarCrate {
2387 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2388 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2389 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2390 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2391 // definitions actually produced by `macro` and `macro` definitions produced by
2392 // `macro_rules!`, but at least such configurations are not stable yet.
2393 ctxt = ctxt.modern_and_legacy();
2394 let mut iter = ctxt.marks().into_iter().rev().peekable();
2395 let mut result = None;
2396 // Find the last modern mark from the end if it exists.
2397 while let Some(&(mark, transparency)) = iter.peek() {
2398 if transparency == Transparency::Opaque {
2399 result = Some(mark);
2405 // Then find the last legacy mark from the end if it exists.
2406 for (mark, transparency) in iter {
2407 if transparency == Transparency::SemiTransparent {
2408 result = Some(mark);
2415 ctxt = ctxt.modern();
2416 ctxt.adjust(Mark::root())
2418 let module = match mark {
2419 Some(def) => self.macro_def_scope(def),
2420 None => return self.graph_root,
2422 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2425 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2426 let mut module = self.get_module(module.normal_ancestor_id);
2427 while module.span.ctxt().modern() != *ctxt {
2428 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2429 module = self.get_module(parent.normal_ancestor_id);
2436 // We maintain a list of value ribs and type ribs.
2438 // Simultaneously, we keep track of the current position in the module
2439 // graph in the `current_module` pointer. When we go to resolve a name in
2440 // the value or type namespaces, we first look through all the ribs and
2441 // then query the module graph. When we resolve a name in the module
2442 // namespace, we can skip all the ribs (since nested modules are not
2443 // allowed within blocks in Rust) and jump straight to the current module
2446 // Named implementations are handled separately. When we find a method
2447 // call, we consult the module node to find all of the implementations in
2448 // scope. This information is lazily cached in the module node. We then
2449 // generate a fake "implementation scope" containing all the
2450 // implementations thus found, for compatibility with old resolve pass.
2452 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2453 where F: FnOnce(&mut Resolver<'_>) -> T
2455 let id = self.definitions.local_def_id(id);
2456 let module = self.module_map.get(&id).cloned(); // clones a reference
2457 if let Some(module) = module {
2458 // Move down in the graph.
2459 let orig_module = replace(&mut self.current_module, module);
2460 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2461 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2463 self.finalize_current_module_macro_resolutions();
2466 self.current_module = orig_module;
2467 self.ribs[ValueNS].pop();
2468 self.ribs[TypeNS].pop();
2475 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2476 /// is returned by the given predicate function
2478 /// Stops after meeting a closure.
2479 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2480 where P: Fn(&Rib<'_, NodeId>, Ident) -> Option<R>
2482 for rib in self.label_ribs.iter().rev() {
2485 // If an invocation of this macro created `ident`, give up on `ident`
2486 // and switch to `ident`'s source from the macro definition.
2487 MacroDefinition(def) => {
2488 if def == self.macro_def(ident.span.ctxt()) {
2489 ident.span.remove_mark();
2493 // Do not resolve labels across function boundary
2497 let r = pred(rib, ident);
2505 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2506 debug!("resolve_adt");
2507 self.with_current_self_item(item, |this| {
2508 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2509 let item_def_id = this.definitions.local_def_id(item.id);
2510 this.with_self_rib(Res::SelfTy(None, Some(item_def_id)), |this| {
2511 visit::walk_item(this, item);
2517 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2518 let segments = &use_tree.prefix.segments;
2519 if !segments.is_empty() {
2520 let ident = segments[0].ident;
2521 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2525 let nss = match use_tree.kind {
2526 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2529 let report_error = |this: &Self, ns| {
2530 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2531 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2535 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2536 Some(LexicalScopeBinding::Res(..)) => {
2537 report_error(self, ns);
2539 Some(LexicalScopeBinding::Item(binding)) => {
2540 let orig_blacklisted_binding =
2541 mem::replace(&mut self.blacklisted_binding, Some(binding));
2542 if let Some(LexicalScopeBinding::Res(..)) =
2543 self.resolve_ident_in_lexical_scope(ident, ns, None,
2544 use_tree.prefix.span) {
2545 report_error(self, ns);
2547 self.blacklisted_binding = orig_blacklisted_binding;
2552 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2553 for (use_tree, _) in use_trees {
2554 self.future_proof_import(use_tree);
2559 fn resolve_item(&mut self, item: &Item) {
2560 let name = item.ident.name;
2561 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2564 ItemKind::Ty(_, ref generics) |
2565 ItemKind::Fn(_, _, ref generics, _) |
2566 ItemKind::Existential(_, ref generics) => {
2567 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2568 |this| visit::walk_item(this, item));
2571 ItemKind::Enum(_, ref generics) |
2572 ItemKind::Struct(_, ref generics) |
2573 ItemKind::Union(_, ref generics) => {
2574 self.resolve_adt(item, generics);
2577 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2578 self.resolve_implementation(generics,
2584 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2585 // Create a new rib for the trait-wide type parameters.
2586 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2587 let local_def_id = this.definitions.local_def_id(item.id);
2588 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2589 this.visit_generics(generics);
2590 walk_list!(this, visit_param_bound, bounds);
2592 for trait_item in trait_items {
2593 let generic_params = HasGenericParams(&trait_item.generics,
2595 this.with_generic_param_rib(generic_params, |this| {
2596 match trait_item.node {
2597 TraitItemKind::Const(ref ty, ref default) => {
2600 // Only impose the restrictions of
2601 // ConstRibKind for an actual constant
2602 // expression in a provided default.
2603 if let Some(ref expr) = *default{
2604 this.with_constant_rib(|this| {
2605 this.visit_expr(expr);
2609 TraitItemKind::Method(_, _) => {
2610 visit::walk_trait_item(this, trait_item)
2612 TraitItemKind::Type(..) => {
2613 visit::walk_trait_item(this, trait_item)
2615 TraitItemKind::Macro(_) => {
2616 panic!("unexpanded macro in resolve!")
2625 ItemKind::TraitAlias(ref generics, ref bounds) => {
2626 // Create a new rib for the trait-wide type parameters.
2627 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2628 let local_def_id = this.definitions.local_def_id(item.id);
2629 this.with_self_rib(Res::SelfTy(Some(local_def_id), None), |this| {
2630 this.visit_generics(generics);
2631 walk_list!(this, visit_param_bound, bounds);
2636 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2637 self.with_scope(item.id, |this| {
2638 visit::walk_item(this, item);
2642 ItemKind::Static(ref ty, _, ref expr) |
2643 ItemKind::Const(ref ty, ref expr) => {
2644 debug!("resolve_item ItemKind::Const");
2645 self.with_item_rib(|this| {
2647 this.with_constant_rib(|this| {
2648 this.visit_expr(expr);
2653 ItemKind::Use(ref use_tree) => {
2654 self.future_proof_import(use_tree);
2657 ItemKind::ExternCrate(..) |
2658 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2659 // do nothing, these are just around to be encoded
2662 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2666 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2667 where F: FnOnce(&mut Resolver<'_>)
2669 debug!("with_generic_param_rib");
2670 match generic_params {
2671 HasGenericParams(generics, rib_kind) => {
2672 let mut function_type_rib = Rib::new(rib_kind);
2673 let mut function_value_rib = Rib::new(rib_kind);
2674 let mut seen_bindings = FxHashMap::default();
2675 for param in &generics.params {
2677 GenericParamKind::Lifetime { .. } => {}
2678 GenericParamKind::Type { .. } => {
2679 let ident = param.ident.modern();
2680 debug!("with_generic_param_rib: {}", param.id);
2682 if seen_bindings.contains_key(&ident) {
2683 let span = seen_bindings.get(&ident).unwrap();
2684 let err = ResolutionError::NameAlreadyUsedInParameterList(
2688 resolve_error(self, param.ident.span, err);
2690 seen_bindings.entry(ident).or_insert(param.ident.span);
2692 // Plain insert (no renaming).
2695 self.definitions.local_def_id(param.id),
2697 function_type_rib.bindings.insert(ident, res);
2698 self.record_partial_res(param.id, PartialRes::new(res));
2700 GenericParamKind::Const { .. } => {
2701 let ident = param.ident.modern();
2702 debug!("with_generic_param_rib: {}", param.id);
2704 if seen_bindings.contains_key(&ident) {
2705 let span = seen_bindings.get(&ident).unwrap();
2706 let err = ResolutionError::NameAlreadyUsedInParameterList(
2710 resolve_error(self, param.ident.span, err);
2712 seen_bindings.entry(ident).or_insert(param.ident.span);
2715 DefKind::ConstParam,
2716 self.definitions.local_def_id(param.id),
2718 function_value_rib.bindings.insert(ident, res);
2719 self.record_partial_res(param.id, PartialRes::new(res));
2723 self.ribs[ValueNS].push(function_value_rib);
2724 self.ribs[TypeNS].push(function_type_rib);
2727 NoGenericParams => {
2734 if let HasGenericParams(..) = generic_params {
2735 self.ribs[TypeNS].pop();
2736 self.ribs[ValueNS].pop();
2740 fn with_label_rib<F>(&mut self, f: F)
2741 where F: FnOnce(&mut Resolver<'_>)
2743 self.label_ribs.push(Rib::new(NormalRibKind));
2745 self.label_ribs.pop();
2748 fn with_item_rib<F>(&mut self, f: F)
2749 where F: FnOnce(&mut Resolver<'_>)
2751 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2752 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2754 self.ribs[TypeNS].pop();
2755 self.ribs[ValueNS].pop();
2758 fn with_constant_rib<F>(&mut self, f: F)
2759 where F: FnOnce(&mut Resolver<'_>)
2761 debug!("with_constant_rib");
2762 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2763 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2765 self.label_ribs.pop();
2766 self.ribs[ValueNS].pop();
2769 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2770 where F: FnOnce(&mut Resolver<'_>) -> T
2772 // Handle nested impls (inside fn bodies)
2773 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2774 let result = f(self);
2775 self.current_self_type = previous_value;
2779 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2780 where F: FnOnce(&mut Resolver<'_>) -> T
2782 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2783 let result = f(self);
2784 self.current_self_item = previous_value;
2788 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2789 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2790 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2792 let mut new_val = None;
2793 let mut new_id = None;
2794 if let Some(trait_ref) = opt_trait_ref {
2795 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2796 let res = self.smart_resolve_path_fragment(
2800 trait_ref.path.span,
2801 PathSource::Trait(AliasPossibility::No),
2802 CrateLint::SimplePath(trait_ref.ref_id),
2804 if res != Res::Err {
2805 new_id = Some(res.def_id());
2806 let span = trait_ref.path.span;
2807 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2808 self.resolve_path_without_parent_scope(
2813 CrateLint::SimplePath(trait_ref.ref_id),
2816 new_val = Some((module, trait_ref.clone()));
2820 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2821 let result = f(self, new_id);
2822 self.current_trait_ref = original_trait_ref;
2826 fn with_self_rib<F>(&mut self, self_res: Res, f: F)
2827 where F: FnOnce(&mut Resolver<'_>)
2829 let mut self_type_rib = Rib::new(NormalRibKind);
2831 // Plain insert (no renaming, since types are not currently hygienic)
2832 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2833 self.ribs[TypeNS].push(self_type_rib);
2835 self.ribs[TypeNS].pop();
2838 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2839 where F: FnOnce(&mut Resolver<'_>)
2841 let self_res = Res::SelfCtor(impl_id);
2842 let mut self_type_rib = Rib::new(NormalRibKind);
2843 self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
2844 self.ribs[ValueNS].push(self_type_rib);
2846 self.ribs[ValueNS].pop();
2849 fn resolve_implementation(&mut self,
2850 generics: &Generics,
2851 opt_trait_reference: &Option<TraitRef>,
2854 impl_items: &[ImplItem]) {
2855 debug!("resolve_implementation");
2856 // If applicable, create a rib for the type parameters.
2857 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2858 // Dummy self type for better errors if `Self` is used in the trait path.
2859 this.with_self_rib(Res::SelfTy(None, None), |this| {
2860 // Resolve the trait reference, if necessary.
2861 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2862 let item_def_id = this.definitions.local_def_id(item_id);
2863 this.with_self_rib(Res::SelfTy(trait_id, Some(item_def_id)), |this| {
2864 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2865 // Resolve type arguments in the trait path.
2866 visit::walk_trait_ref(this, trait_ref);
2868 // Resolve the self type.
2869 this.visit_ty(self_type);
2870 // Resolve the generic parameters.
2871 this.visit_generics(generics);
2872 // Resolve the items within the impl.
2873 this.with_current_self_type(self_type, |this| {
2874 this.with_self_struct_ctor_rib(item_def_id, |this| {
2875 debug!("resolve_implementation with_self_struct_ctor_rib");
2876 for impl_item in impl_items {
2877 this.resolve_visibility(&impl_item.vis);
2879 // We also need a new scope for the impl item type parameters.
2880 let generic_params = HasGenericParams(&impl_item.generics,
2882 this.with_generic_param_rib(generic_params, |this| {
2883 use self::ResolutionError::*;
2884 match impl_item.node {
2885 ImplItemKind::Const(..) => {
2887 "resolve_implementation ImplItemKind::Const",
2889 // If this is a trait impl, ensure the const
2891 this.check_trait_item(
2895 |n, s| ConstNotMemberOfTrait(n, s),
2898 this.with_constant_rib(|this| {
2899 visit::walk_impl_item(this, impl_item)
2902 ImplItemKind::Method(..) => {
2903 // If this is a trait impl, ensure the method
2905 this.check_trait_item(impl_item.ident,
2908 |n, s| MethodNotMemberOfTrait(n, s));
2910 visit::walk_impl_item(this, impl_item);
2912 ImplItemKind::Type(ref ty) => {
2913 // If this is a trait impl, ensure the type
2915 this.check_trait_item(impl_item.ident,
2918 |n, s| TypeNotMemberOfTrait(n, s));
2922 ImplItemKind::Existential(ref bounds) => {
2923 // If this is a trait impl, ensure the type
2925 this.check_trait_item(impl_item.ident,
2928 |n, s| TypeNotMemberOfTrait(n, s));
2930 for bound in bounds {
2931 this.visit_param_bound(bound);
2934 ImplItemKind::Macro(_) =>
2935 panic!("unexpanded macro in resolve!"),
2947 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2948 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2950 // If there is a TraitRef in scope for an impl, then the method must be in the
2952 if let Some((module, _)) = self.current_trait_ref {
2953 if self.resolve_ident_in_module(
2954 ModuleOrUniformRoot::Module(module),
2961 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2962 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2967 fn resolve_local(&mut self, local: &Local) {
2968 // Resolve the type.
2969 walk_list!(self, visit_ty, &local.ty);
2971 // Resolve the initializer.
2972 walk_list!(self, visit_expr, &local.init);
2974 // Resolve the pattern.
2975 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2978 // build a map from pattern identifiers to binding-info's.
2979 // this is done hygienically. This could arise for a macro
2980 // that expands into an or-pattern where one 'x' was from the
2981 // user and one 'x' came from the macro.
2982 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2983 let mut binding_map = FxHashMap::default();
2985 pat.walk(&mut |pat| {
2986 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2987 if sub_pat.is_some() || match self.partial_res_map.get(&pat.id)
2988 .map(|res| res.base_res()) {
2989 Some(Res::Local(..)) => true,
2992 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2993 binding_map.insert(ident, binding_info);
3002 // check that all of the arms in an or-pattern have exactly the
3003 // same set of bindings, with the same binding modes for each.
3004 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
3005 if pats.is_empty() {
3009 let mut missing_vars = FxHashMap::default();
3010 let mut inconsistent_vars = FxHashMap::default();
3011 for (i, p) in pats.iter().enumerate() {
3012 let map_i = self.binding_mode_map(&p);
3014 for (j, q) in pats.iter().enumerate() {
3019 let map_j = self.binding_mode_map(&q);
3020 for (&key, &binding_i) in &map_i {
3021 if map_j.is_empty() { // Account for missing bindings when
3022 let binding_error = missing_vars // map_j has none.
3024 .or_insert(BindingError {
3026 origin: BTreeSet::new(),
3027 target: BTreeSet::new(),
3029 binding_error.origin.insert(binding_i.span);
3030 binding_error.target.insert(q.span);
3032 for (&key_j, &binding_j) in &map_j {
3033 match map_i.get(&key_j) {
3034 None => { // missing binding
3035 let binding_error = missing_vars
3037 .or_insert(BindingError {
3039 origin: BTreeSet::new(),
3040 target: BTreeSet::new(),
3042 binding_error.origin.insert(binding_j.span);
3043 binding_error.target.insert(p.span);
3045 Some(binding_i) => { // check consistent binding
3046 if binding_i.binding_mode != binding_j.binding_mode {
3049 .or_insert((binding_j.span, binding_i.span));
3057 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
3058 missing_vars.sort();
3059 for (_, v) in missing_vars {
3061 *v.origin.iter().next().unwrap(),
3062 ResolutionError::VariableNotBoundInPattern(v));
3064 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
3065 inconsistent_vars.sort();
3066 for (name, v) in inconsistent_vars {
3067 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
3071 fn resolve_arm(&mut self, arm: &Arm) {
3072 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3074 let mut bindings_list = FxHashMap::default();
3075 for pattern in &arm.pats {
3076 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
3079 // This has to happen *after* we determine which pat_idents are variants.
3080 self.check_consistent_bindings(&arm.pats);
3082 if let Some(ast::Guard::If(ref expr)) = arm.guard {
3083 self.visit_expr(expr)
3085 self.visit_expr(&arm.body);
3087 self.ribs[ValueNS].pop();
3090 fn resolve_block(&mut self, block: &Block) {
3091 debug!("(resolving block) entering block");
3092 // Move down in the graph, if there's an anonymous module rooted here.
3093 let orig_module = self.current_module;
3094 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
3096 let mut num_macro_definition_ribs = 0;
3097 if let Some(anonymous_module) = anonymous_module {
3098 debug!("(resolving block) found anonymous module, moving down");
3099 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3100 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3101 self.current_module = anonymous_module;
3102 self.finalize_current_module_macro_resolutions();
3104 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3107 // Descend into the block.
3108 for stmt in &block.stmts {
3109 if let ast::StmtKind::Item(ref item) = stmt.node {
3110 if let ast::ItemKind::MacroDef(..) = item.node {
3111 num_macro_definition_ribs += 1;
3112 let res = self.definitions.local_def_id(item.id);
3113 self.ribs[ValueNS].push(Rib::new(MacroDefinition(res)));
3114 self.label_ribs.push(Rib::new(MacroDefinition(res)));
3118 self.visit_stmt(stmt);
3122 self.current_module = orig_module;
3123 for _ in 0 .. num_macro_definition_ribs {
3124 self.ribs[ValueNS].pop();
3125 self.label_ribs.pop();
3127 self.ribs[ValueNS].pop();
3128 if anonymous_module.is_some() {
3129 self.ribs[TypeNS].pop();
3131 debug!("(resolving block) leaving block");
3134 fn fresh_binding(&mut self,
3137 outer_pat_id: NodeId,
3138 pat_src: PatternSource,
3139 bindings: &mut FxHashMap<Ident, NodeId>)
3141 // Add the binding to the local ribs, if it
3142 // doesn't already exist in the bindings map. (We
3143 // must not add it if it's in the bindings map
3144 // because that breaks the assumptions later
3145 // passes make about or-patterns.)
3146 let ident = ident.modern_and_legacy();
3147 let mut res = Res::Local(pat_id);
3148 match bindings.get(&ident).cloned() {
3149 Some(id) if id == outer_pat_id => {
3150 // `Variant(a, a)`, error
3154 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3158 Some(..) if pat_src == PatternSource::FnParam => {
3159 // `fn f(a: u8, a: u8)`, error
3163 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3167 Some(..) if pat_src == PatternSource::Match ||
3168 pat_src == PatternSource::IfLet ||
3169 pat_src == PatternSource::WhileLet => {
3170 // `Variant1(a) | Variant2(a)`, ok
3171 // Reuse definition from the first `a`.
3172 res = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3175 span_bug!(ident.span, "two bindings with the same name from \
3176 unexpected pattern source {:?}", pat_src);
3179 // A completely fresh binding, add to the lists if it's valid.
3180 if ident.name != kw::Invalid {
3181 bindings.insert(ident, outer_pat_id);
3182 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, res);
3190 fn resolve_pattern(&mut self,
3192 pat_src: PatternSource,
3193 // Maps idents to the node ID for the
3194 // outermost pattern that binds them.
3195 bindings: &mut FxHashMap<Ident, NodeId>) {
3196 // Visit all direct subpatterns of this pattern.
3197 let outer_pat_id = pat.id;
3198 pat.walk(&mut |pat| {
3199 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3201 PatKind::Ident(bmode, ident, ref opt_pat) => {
3202 // First try to resolve the identifier as some existing
3203 // entity, then fall back to a fresh binding.
3204 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3206 .and_then(LexicalScopeBinding::item);
3207 let res = binding.map(NameBinding::res).and_then(|res| {
3208 let is_syntactic_ambiguity = opt_pat.is_none() &&
3209 bmode == BindingMode::ByValue(Mutability::Immutable);
3211 Res::Def(DefKind::Ctor(_, CtorKind::Const), _) |
3212 Res::Def(DefKind::Const, _) if is_syntactic_ambiguity => {
3213 // Disambiguate in favor of a unit struct/variant
3214 // or constant pattern.
3215 self.record_use(ident, ValueNS, binding.unwrap(), false);
3218 Res::Def(DefKind::Ctor(..), _)
3219 | Res::Def(DefKind::Const, _)
3220 | Res::Def(DefKind::Static, _) => {
3221 // This is unambiguously a fresh binding, either syntactically
3222 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3223 // to something unusable as a pattern (e.g., constructor function),
3224 // but we still conservatively report an error, see
3225 // issues/33118#issuecomment-233962221 for one reason why.
3229 ResolutionError::BindingShadowsSomethingUnacceptable(
3230 pat_src.descr(), ident.name, binding.unwrap())
3234 Res::Def(DefKind::Fn, _) | Res::Err => {
3235 // These entities are explicitly allowed
3236 // to be shadowed by fresh bindings.
3240 span_bug!(ident.span, "unexpected resolution for an \
3241 identifier in pattern: {:?}", res);
3244 }).unwrap_or_else(|| {
3245 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3248 self.record_partial_res(pat.id, PartialRes::new(res));
3251 PatKind::TupleStruct(ref path, ..) => {
3252 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3255 PatKind::Path(ref qself, ref path) => {
3256 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3259 PatKind::Struct(ref path, ..) => {
3260 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3268 visit::walk_pat(self, pat);
3271 // High-level and context dependent path resolution routine.
3272 // Resolves the path and records the resolution into definition map.
3273 // If resolution fails tries several techniques to find likely
3274 // resolution candidates, suggest imports or other help, and report
3275 // errors in user friendly way.
3276 fn smart_resolve_path(&mut self,
3278 qself: Option<&QSelf>,
3280 source: PathSource<'_>) {
3281 self.smart_resolve_path_fragment(
3284 &Segment::from_path(path),
3287 CrateLint::SimplePath(id),
3291 fn smart_resolve_path_fragment(&mut self,
3293 qself: Option<&QSelf>,
3296 source: PathSource<'_>,
3297 crate_lint: CrateLint)
3299 let ns = source.namespace();
3300 let is_expected = &|res| source.is_expected(res);
3302 let report_errors = |this: &mut Self, res: Option<Res>| {
3303 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, res);
3304 let def_id = this.current_module.normal_ancestor_id;
3305 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3306 let better = res.is_some();
3307 this.use_injections.push(UseError { err, candidates, node_id, better });
3308 PartialRes::new(Res::Err)
3311 let partial_res = match self.resolve_qpath_anywhere(
3317 source.defer_to_typeck(),
3318 source.global_by_default(),
3321 Some(partial_res) if partial_res.unresolved_segments() == 0 => {
3322 if is_expected(partial_res.base_res()) || partial_res.base_res() == Res::Err {
3325 // Add a temporary hack to smooth the transition to new struct ctor
3326 // visibility rules. See #38932 for more details.
3328 if let Res::Def(DefKind::Struct, def_id) = partial_res.base_res() {
3329 if let Some((ctor_res, ctor_vis))
3330 = self.struct_constructors.get(&def_id).cloned() {
3331 if is_expected(ctor_res) && self.is_accessible(ctor_vis) {
3332 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3333 self.session.buffer_lint(lint, id, span,
3334 "private struct constructors are not usable through \
3335 re-exports in outer modules",
3337 res = Some(PartialRes::new(ctor_res));
3342 res.unwrap_or_else(|| report_errors(self, Some(partial_res.base_res())))
3345 Some(partial_res) if source.defer_to_typeck() => {
3346 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3347 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3348 // it needs to be added to the trait map.
3350 let item_name = path.last().unwrap().ident;
3351 let traits = self.get_traits_containing_item(item_name, ns);
3352 self.trait_map.insert(id, traits);
3355 let mut std_path = vec![Segment::from_ident(Ident::with_empty_ctxt(sym::std))];
3356 std_path.extend(path);
3357 if self.primitive_type_table.primitive_types.contains_key(&path[0].ident.name) {
3358 let cl = CrateLint::No;
3360 if let PathResult::Module(_) | PathResult::NonModule(_) =
3361 self.resolve_path_without_parent_scope(&std_path, ns, false, span, cl)
3363 // check if we wrote `str::from_utf8` instead of `std::str::from_utf8`
3364 let item_span = path.iter().last().map(|segment| segment.ident.span)
3366 debug!("accessed item from `std` submodule as a bare type {:?}", std_path);
3367 let mut hm = self.session.confused_type_with_std_module.borrow_mut();
3368 hm.insert(item_span, span);
3369 // In some places (E0223) we only have access to the full path
3370 hm.insert(span, span);
3375 _ => report_errors(self, None)
3378 if let PathSource::TraitItem(..) = source {} else {
3379 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3380 self.record_partial_res(id, partial_res);
3385 /// Only used in a specific case of type ascription suggestions
3387 fn get_colon_suggestion_span(&self, start: Span) -> Span {
3388 let cm = self.session.source_map();
3389 start.to(cm.next_point(start))
3392 fn type_ascription_suggestion(
3394 err: &mut DiagnosticBuilder<'_>,
3397 debug!("type_ascription_suggetion {:?}", base_span);
3398 let cm = self.session.source_map();
3399 let base_snippet = cm.span_to_snippet(base_span);
3400 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3401 if let Some(sp) = self.current_type_ascription.last() {
3404 // Try to find the `:`; bail on first non-':' / non-whitespace.
3405 sp = cm.next_point(sp);
3406 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3407 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3408 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3410 let mut show_label = true;
3411 if line_sp != line_base_sp {
3412 err.span_suggestion_short(
3414 "did you mean to use `;` here instead?",
3416 Applicability::MaybeIncorrect,
3419 let colon_sp = self.get_colon_suggestion_span(sp);
3420 let after_colon_sp = self.get_colon_suggestion_span(
3421 colon_sp.shrink_to_hi(),
3423 if !cm.span_to_snippet(after_colon_sp).map(|s| s == " ")
3426 err.span_suggestion(
3428 "maybe you meant to write a path separator here",
3430 Applicability::MaybeIncorrect,
3434 if let Ok(base_snippet) = base_snippet {
3435 let mut sp = after_colon_sp;
3437 // Try to find an assignment
3438 sp = cm.next_point(sp);
3439 let snippet = cm.span_to_snippet(sp.to(cm.next_point(sp)));
3441 Ok(ref x) if x.as_str() == "=" => {
3442 err.span_suggestion(
3444 "maybe you meant to write an assignment here",
3445 format!("let {}", base_snippet),
3446 Applicability::MaybeIncorrect,
3451 Ok(ref x) if x.as_str() == "\n" => break,
3459 err.span_label(base_span,
3460 "expecting a type here because of type ascription");
3463 } else if !snippet.trim().is_empty() {
3464 debug!("tried to find type ascription `:` token, couldn't find it");
3474 fn self_type_is_available(&mut self, span: Span) -> bool {
3475 let binding = self.resolve_ident_in_lexical_scope(Ident::with_empty_ctxt(kw::SelfUpper),
3476 TypeNS, None, span);
3477 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3480 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3481 let ident = Ident::new(kw::SelfLower, self_span);
3482 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3483 if let Some(LexicalScopeBinding::Res(res)) = binding { res != Res::Err } else { false }
3486 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3487 fn resolve_qpath_anywhere(
3490 qself: Option<&QSelf>,
3492 primary_ns: Namespace,
3494 defer_to_typeck: bool,
3495 global_by_default: bool,
3496 crate_lint: CrateLint,
3497 ) -> Option<PartialRes> {
3498 let mut fin_res = None;
3499 // FIXME: can't resolve paths in macro namespace yet, macros are
3500 // processed by the little special hack below.
3501 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3502 if i == 0 || ns != primary_ns {
3503 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3504 // If defer_to_typeck, then resolution > no resolution,
3505 // otherwise full resolution > partial resolution > no resolution.
3506 Some(partial_res) if partial_res.unresolved_segments() == 0 ||
3508 return Some(partial_res),
3509 partial_res => if fin_res.is_none() { fin_res = partial_res },
3513 if primary_ns != MacroNS &&
3514 (self.macro_names.contains(&path[0].ident.modern()) ||
3515 self.builtin_macros.get(&path[0].ident.name).cloned()
3516 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3517 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3518 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3519 // Return some dummy definition, it's enough for error reporting.
3520 return Some(PartialRes::new(Res::Def(
3521 DefKind::Macro(MacroKind::Bang),
3522 DefId::local(CRATE_DEF_INDEX),
3528 /// Handles paths that may refer to associated items.
3532 qself: Option<&QSelf>,
3536 global_by_default: bool,
3537 crate_lint: CrateLint,
3538 ) -> Option<PartialRes> {
3540 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3541 ns={:?}, span={:?}, global_by_default={:?})",
3550 if let Some(qself) = qself {
3551 if qself.position == 0 {
3552 // This is a case like `<T>::B`, where there is no
3553 // trait to resolve. In that case, we leave the `B`
3554 // segment to be resolved by type-check.
3555 return Some(PartialRes::with_unresolved_segments(
3556 Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX)), path.len()
3560 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3562 // Currently, `path` names the full item (`A::B::C`, in
3563 // our example). so we extract the prefix of that that is
3564 // the trait (the slice upto and including
3565 // `qself.position`). And then we recursively resolve that,
3566 // but with `qself` set to `None`.
3568 // However, setting `qself` to none (but not changing the
3569 // span) loses the information about where this path
3570 // *actually* appears, so for the purposes of the crate
3571 // lint we pass along information that this is the trait
3572 // name from a fully qualified path, and this also
3573 // contains the full span (the `CrateLint::QPathTrait`).
3574 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3575 let partial_res = self.smart_resolve_path_fragment(
3578 &path[..=qself.position],
3580 PathSource::TraitItem(ns),
3581 CrateLint::QPathTrait {
3583 qpath_span: qself.path_span,
3587 // The remaining segments (the `C` in our example) will
3588 // have to be resolved by type-check, since that requires doing
3589 // trait resolution.
3590 return Some(PartialRes::with_unresolved_segments(
3591 partial_res.base_res(),
3592 partial_res.unresolved_segments() + path.len() - qself.position - 1,
3596 let result = match self.resolve_path_without_parent_scope(
3603 PathResult::NonModule(path_res) => path_res,
3604 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3605 PartialRes::new(module.res().unwrap())
3607 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3608 // don't report an error right away, but try to fallback to a primitive type.
3609 // So, we are still able to successfully resolve something like
3611 // use std::u8; // bring module u8 in scope
3612 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3613 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3614 // // not to non-existent std::u8::max_value
3617 // Such behavior is required for backward compatibility.
3618 // The same fallback is used when `a` resolves to nothing.
3619 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3620 PathResult::Failed { .. }
3621 if (ns == TypeNS || path.len() > 1) &&
3622 self.primitive_type_table.primitive_types
3623 .contains_key(&path[0].ident.name) => {
3624 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3625 PartialRes::with_unresolved_segments(Res::PrimTy(prim), path.len() - 1)
3627 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3628 PartialRes::new(module.res().unwrap()),
3629 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
3630 resolve_error(self, span, ResolutionError::FailedToResolve { label, suggestion });
3631 PartialRes::new(Res::Err)
3633 PathResult::Module(..) | PathResult::Failed { .. } => return None,
3634 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3637 if path.len() > 1 && !global_by_default && result.base_res() != Res::Err &&
3638 path[0].ident.name != kw::PathRoot &&
3639 path[0].ident.name != kw::DollarCrate {
3640 let unqualified_result = {
3641 match self.resolve_path_without_parent_scope(
3642 &[*path.last().unwrap()],
3648 PathResult::NonModule(path_res) => path_res.base_res(),
3649 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3650 module.res().unwrap(),
3651 _ => return Some(result),
3654 if result.base_res() == unqualified_result {
3655 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3656 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3663 fn resolve_path_without_parent_scope(
3666 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3669 crate_lint: CrateLint,
3670 ) -> PathResult<'a> {
3671 // Macro and import paths must have full parent scope available during resolution,
3672 // other paths will do okay with parent module alone.
3673 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3674 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3675 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3681 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3682 parent_scope: &ParentScope<'a>,
3685 crate_lint: CrateLint,
3686 ) -> PathResult<'a> {
3687 let mut module = None;
3688 let mut allow_super = true;
3689 let mut second_binding = None;
3690 self.current_module = parent_scope.module;
3693 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3694 path_span={:?}, crate_lint={:?})",
3702 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3703 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3704 let record_segment_res = |this: &mut Self, res| {
3706 if let Some(id) = id {
3707 if !this.partial_res_map.contains_key(&id) {
3708 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3709 this.record_partial_res(id, PartialRes::new(res));
3715 let is_last = i == path.len() - 1;
3716 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3717 let name = ident.name;
3719 allow_super &= ns == TypeNS &&
3720 (name == kw::SelfLower ||
3724 if allow_super && name == kw::Super {
3725 let mut ctxt = ident.span.ctxt().modern();
3726 let self_module = match i {
3727 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3729 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3733 if let Some(self_module) = self_module {
3734 if let Some(parent) = self_module.parent {
3735 module = Some(ModuleOrUniformRoot::Module(
3736 self.resolve_self(&mut ctxt, parent)));
3740 let msg = "there are too many initial `super`s.".to_string();
3741 return PathResult::Failed {
3745 is_error_from_last_segment: false,
3749 if name == kw::SelfLower {
3750 let mut ctxt = ident.span.ctxt().modern();
3751 module = Some(ModuleOrUniformRoot::Module(
3752 self.resolve_self(&mut ctxt, self.current_module)));
3755 if name == kw::PathRoot && ident.span.rust_2018() {
3756 module = Some(ModuleOrUniformRoot::ExternPrelude);
3759 if name == kw::PathRoot &&
3760 ident.span.rust_2015() && self.session.rust_2018() {
3761 // `::a::b` from 2015 macro on 2018 global edition
3762 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3765 if name == kw::PathRoot ||
3766 name == kw::Crate ||
3767 name == kw::DollarCrate {
3768 // `::a::b`, `crate::a::b` or `$crate::a::b`
3769 module = Some(ModuleOrUniformRoot::Module(
3770 self.resolve_crate_root(ident)));
3776 // Report special messages for path segment keywords in wrong positions.
3777 if ident.is_path_segment_keyword() && i != 0 {
3778 let name_str = if name == kw::PathRoot {
3779 "crate root".to_string()
3781 format!("`{}`", name)
3783 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
3784 format!("global paths cannot start with {}", name_str)
3786 format!("{} in paths can only be used in start position", name_str)
3788 return PathResult::Failed {
3792 is_error_from_last_segment: false,
3796 let binding = if let Some(module) = module {
3797 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3798 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3799 assert!(ns == TypeNS);
3800 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3801 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3802 record_used, path_span)
3804 let record_used_id =
3805 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3806 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3807 // we found a locally-imported or available item/module
3808 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3809 // we found a local variable or type param
3810 Some(LexicalScopeBinding::Res(res))
3811 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3812 record_segment_res(self, res);
3813 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3817 _ => Err(Determinacy::determined(record_used)),
3824 second_binding = Some(binding);
3826 let res = binding.res();
3827 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
3828 if let Some(next_module) = binding.module() {
3829 module = Some(ModuleOrUniformRoot::Module(next_module));
3830 record_segment_res(self, res);
3831 } else if res == Res::ToolMod && i + 1 != path.len() {
3832 if binding.is_import() {
3833 self.session.struct_span_err(
3834 ident.span, "cannot use a tool module through an import"
3836 binding.span, "the tool module imported here"
3839 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
3840 return PathResult::NonModule(PartialRes::new(res));
3841 } else if res == Res::Err {
3842 return PathResult::NonModule(PartialRes::new(Res::Err));
3843 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3844 self.lint_if_path_starts_with_module(
3850 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3851 res, path.len() - i - 1
3854 let label = format!(
3855 "`{}` is {} {}, not a module",
3861 return PathResult::Failed {
3865 is_error_from_last_segment: is_last,
3869 Err(Undetermined) => return PathResult::Indeterminate,
3870 Err(Determined) => {
3871 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3872 if opt_ns.is_some() && !module.is_normal() {
3873 return PathResult::NonModule(PartialRes::with_unresolved_segments(
3874 module.res().unwrap(), path.len() - i
3878 let module_res = match module {
3879 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
3882 let (label, suggestion) = if module_res == self.graph_root.res() {
3883 let is_mod = |res| {
3884 match res { Res::Def(DefKind::Mod, _) => true, _ => false }
3886 let mut candidates =
3887 self.lookup_import_candidates(ident, TypeNS, is_mod);
3888 candidates.sort_by_cached_key(|c| {
3889 (c.path.segments.len(), c.path.to_string())
3891 if let Some(candidate) = candidates.get(0) {
3893 String::from("unresolved import"),
3895 vec![(ident.span, candidate.path.to_string())],
3896 String::from("a similar path exists"),
3897 Applicability::MaybeIncorrect,
3900 } else if !ident.is_reserved() {
3901 (format!("maybe a missing `extern crate {};`?", ident), None)
3903 // the parser will already have complained about the keyword being used
3904 return PathResult::NonModule(PartialRes::new(Res::Err));
3907 (format!("use of undeclared type or module `{}`", ident), None)
3909 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
3911 return PathResult::Failed {
3915 is_error_from_last_segment: is_last,
3921 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3923 PathResult::Module(match module {
3924 Some(module) => module,
3925 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3926 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3930 fn lint_if_path_starts_with_module(
3932 crate_lint: CrateLint,
3935 second_binding: Option<&NameBinding<'_>>,
3937 let (diag_id, diag_span) = match crate_lint {
3938 CrateLint::No => return,
3939 CrateLint::SimplePath(id) => (id, path_span),
3940 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3941 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3944 let first_name = match path.get(0) {
3945 // In the 2018 edition this lint is a hard error, so nothing to do
3946 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3950 // We're only interested in `use` paths which should start with
3951 // `{{root}}` currently.
3952 if first_name != kw::PathRoot {
3957 // If this import looks like `crate::...` it's already good
3958 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
3959 // Otherwise go below to see if it's an extern crate
3961 // If the path has length one (and it's `PathRoot` most likely)
3962 // then we don't know whether we're gonna be importing a crate or an
3963 // item in our crate. Defer this lint to elsewhere
3967 // If the first element of our path was actually resolved to an
3968 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3969 // warning, this looks all good!
3970 if let Some(binding) = second_binding {
3971 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3972 // Careful: we still want to rewrite paths from
3973 // renamed extern crates.
3974 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3980 let diag = lint::builtin::BuiltinLintDiagnostics
3981 ::AbsPathWithModule(diag_span);
3982 self.session.buffer_lint_with_diagnostic(
3983 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3985 "absolute paths must start with `self`, `super`, \
3986 `crate`, or an external crate name in the 2018 edition",
3990 // Validate a local resolution (from ribs).
3991 fn validate_res_from_ribs(
3999 debug!("validate_res_from_ribs({:?})", res);
4000 let ribs = &self.ribs[ns][rib_index + 1..];
4002 // An invalid forward use of a type parameter from a previous default.
4003 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4005 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4007 assert_eq!(res, Res::Err);
4011 // An invalid use of a type parameter as the type of a const parameter.
4012 if let TyParamAsConstParamTy = self.ribs[ns][rib_index].kind {
4014 resolve_error(self, span, ResolutionError::ConstParamDependentOnTypeParam);
4016 assert_eq!(res, Res::Err);
4022 use ResolutionError::*;
4023 let mut res_err = None;
4027 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4028 ForwardTyParamBanRibKind | TyParamAsConstParamTy => {
4029 // Nothing to do. Continue.
4031 ItemRibKind | FnItemRibKind | AssocItemRibKind => {
4032 // This was an attempt to access an upvar inside a
4033 // named function item. This is not allowed, so we
4036 // We don't immediately trigger a resolve error, because
4037 // we want certain other resolution errors (namely those
4038 // emitted for `ConstantItemRibKind` below) to take
4040 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
4043 ConstantItemRibKind => {
4044 // Still doesn't deal with upvars
4046 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
4052 if let Some(res_err) = res_err {
4053 resolve_error(self, span, res_err);
4057 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
4060 NormalRibKind | AssocItemRibKind |
4061 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4062 ConstantItemRibKind | TyParamAsConstParamTy => {
4063 // Nothing to do. Continue.
4065 ItemRibKind | FnItemRibKind => {
4066 // This was an attempt to use a type parameter outside its scope.
4071 ResolutionError::GenericParamsFromOuterFunction(res),
4079 Res::Def(DefKind::ConstParam, _) => {
4080 let mut ribs = ribs.iter().peekable();
4081 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
4082 // When declaring const parameters inside function signatures, the first rib
4083 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
4084 // (spuriously) conflicting with the const param.
4088 if let ItemRibKind | FnItemRibKind = rib.kind {
4089 // This was an attempt to use a const parameter outside its scope.
4094 ResolutionError::GenericParamsFromOuterFunction(res),
4106 fn lookup_assoc_candidate<FilterFn>(&mut self,
4109 filter_fn: FilterFn)
4110 -> Option<AssocSuggestion>
4111 where FilterFn: Fn(Res) -> bool
4113 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4115 TyKind::Path(None, _) => Some(t.id),
4116 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4117 // This doesn't handle the remaining `Ty` variants as they are not
4118 // that commonly the self_type, it might be interesting to provide
4119 // support for those in future.
4124 // Fields are generally expected in the same contexts as locals.
4125 if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
4126 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4127 // Look for a field with the same name in the current self_type.
4128 if let Some(resolution) = self.partial_res_map.get(&node_id) {
4129 match resolution.base_res() {
4130 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did)
4131 if resolution.unresolved_segments() == 0 => {
4132 if let Some(field_names) = self.field_names.get(&did) {
4133 if field_names.iter().any(|&field_name| ident.name == field_name) {
4134 return Some(AssocSuggestion::Field);
4144 // Look for associated items in the current trait.
4145 if let Some((module, _)) = self.current_trait_ref {
4146 if let Ok(binding) = self.resolve_ident_in_module(
4147 ModuleOrUniformRoot::Module(module),
4154 let res = binding.res();
4156 return Some(if self.has_self.contains(&res.def_id()) {
4157 AssocSuggestion::MethodWithSelf
4159 AssocSuggestion::AssocItem
4168 fn lookup_typo_candidate<FilterFn>(
4172 filter_fn: FilterFn,
4174 ) -> Option<TypoSuggestion>
4176 FilterFn: Fn(Res) -> bool,
4178 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4179 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4180 if let Some(binding) = resolution.borrow().binding {
4181 if !ident.is_gensymed() && filter_fn(binding.res()) {
4182 names.push(TypoSuggestion {
4183 candidate: ident.name,
4184 article: binding.res().article(),
4185 kind: binding.res().descr(),
4192 let mut names = Vec::new();
4193 if path.len() == 1 {
4194 // Search in lexical scope.
4195 // Walk backwards up the ribs in scope and collect candidates.
4196 for rib in self.ribs[ns].iter().rev() {
4197 // Locals and type parameters
4198 for (ident, &res) in &rib.bindings {
4199 if !ident.is_gensymed() && filter_fn(res) {
4200 names.push(TypoSuggestion {
4201 candidate: ident.name,
4202 article: res.article(),
4208 if let ModuleRibKind(module) = rib.kind {
4209 // Items from this module
4210 add_module_candidates(module, &mut names);
4212 if let ModuleKind::Block(..) = module.kind {
4213 // We can see through blocks
4215 // Items from the prelude
4216 if !module.no_implicit_prelude {
4217 names.extend(self.extern_prelude.clone().iter().flat_map(|(ident, _)| {
4219 .maybe_process_path_extern(ident.name, ident.span)
4220 .and_then(|crate_id| {
4221 let crate_mod = Res::Def(
4225 index: CRATE_DEF_INDEX,
4229 if !ident.is_gensymed() && filter_fn(crate_mod) {
4230 Some(TypoSuggestion {
4231 candidate: ident.name,
4241 if let Some(prelude) = self.prelude {
4242 add_module_candidates(prelude, &mut names);
4249 // Add primitive types to the mix
4250 if filter_fn(Res::PrimTy(Bool)) {
4252 self.primitive_type_table.primitive_types
4258 kind: "primitive type",
4264 // Search in module.
4265 let mod_path = &path[..path.len() - 1];
4266 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4267 mod_path, Some(TypeNS), false, span, CrateLint::No
4269 if let ModuleOrUniformRoot::Module(module) = module {
4270 add_module_candidates(module, &mut names);
4275 let name = path[path.len() - 1].ident.name;
4276 // Make sure error reporting is deterministic.
4277 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4279 match find_best_match_for_name(
4280 names.iter().map(|suggestion| &suggestion.candidate),
4284 Some(found) if found != name => names
4286 .find(|suggestion| suggestion.candidate == found),
4291 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4292 where F: FnOnce(&mut Resolver<'_>)
4294 if let Some(label) = label {
4295 self.unused_labels.insert(id, label.ident.span);
4296 self.with_label_rib(|this| {
4297 let ident = label.ident.modern_and_legacy();
4298 this.label_ribs.last_mut().unwrap().bindings.insert(ident, id);
4306 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4307 self.with_resolved_label(label, id, |this| this.visit_block(block));
4310 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4311 // First, record candidate traits for this expression if it could
4312 // result in the invocation of a method call.
4314 self.record_candidate_traits_for_expr_if_necessary(expr);
4316 // Next, resolve the node.
4318 ExprKind::Path(ref qself, ref path) => {
4319 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4320 visit::walk_expr(self, expr);
4323 ExprKind::Struct(ref path, ..) => {
4324 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4325 visit::walk_expr(self, expr);
4328 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4329 let node_id = self.search_label(label.ident, |rib, ident| {
4330 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4334 // Search again for close matches...
4335 // Picks the first label that is "close enough", which is not necessarily
4336 // the closest match
4337 let close_match = self.search_label(label.ident, |rib, ident| {
4338 let names = rib.bindings.iter().filter_map(|(id, _)| {
4339 if id.span.ctxt() == label.ident.span.ctxt() {
4345 find_best_match_for_name(names, &*ident.as_str(), None)
4347 self.record_partial_res(expr.id, PartialRes::new(Res::Err));
4350 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4354 // Since this res is a label, it is never read.
4355 self.label_res_map.insert(expr.id, node_id);
4356 self.unused_labels.remove(&node_id);
4360 // visit `break` argument if any
4361 visit::walk_expr(self, expr);
4364 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4365 self.visit_expr(subexpression);
4367 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4368 let mut bindings_list = FxHashMap::default();
4370 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4372 // This has to happen *after* we determine which pat_idents are variants
4373 self.check_consistent_bindings(pats);
4374 self.visit_block(if_block);
4375 self.ribs[ValueNS].pop();
4377 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4380 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4382 ExprKind::While(ref subexpression, ref block, label) => {
4383 self.with_resolved_label(label, expr.id, |this| {
4384 this.visit_expr(subexpression);
4385 this.visit_block(block);
4389 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4390 self.with_resolved_label(label, expr.id, |this| {
4391 this.visit_expr(subexpression);
4392 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4393 let mut bindings_list = FxHashMap::default();
4395 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4397 // This has to happen *after* we determine which pat_idents are variants.
4398 this.check_consistent_bindings(pats);
4399 this.visit_block(block);
4400 this.ribs[ValueNS].pop();
4404 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4405 self.visit_expr(subexpression);
4406 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4407 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4409 self.resolve_labeled_block(label, expr.id, block);
4411 self.ribs[ValueNS].pop();
4414 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4416 // Equivalent to `visit::walk_expr` + passing some context to children.
4417 ExprKind::Field(ref subexpression, _) => {
4418 self.resolve_expr(subexpression, Some(expr));
4420 ExprKind::MethodCall(ref segment, ref arguments) => {
4421 let mut arguments = arguments.iter();
4422 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4423 for argument in arguments {
4424 self.resolve_expr(argument, None);
4426 self.visit_path_segment(expr.span, segment);
4429 ExprKind::Call(ref callee, ref arguments) => {
4430 self.resolve_expr(callee, Some(expr));
4431 for argument in arguments {
4432 self.resolve_expr(argument, None);
4435 ExprKind::Type(ref type_expr, _) => {
4436 self.current_type_ascription.push(type_expr.span);
4437 visit::walk_expr(self, expr);
4438 self.current_type_ascription.pop();
4440 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4441 // resolve the arguments within the proper scopes so that usages of them inside the
4442 // closure are detected as upvars rather than normal closure arg usages.
4444 _, IsAsync::Async { .. }, _,
4445 ref fn_decl, ref body, _span,
4447 let rib_kind = NormalRibKind;
4448 self.ribs[ValueNS].push(Rib::new(rib_kind));
4449 // Resolve arguments:
4450 let mut bindings_list = FxHashMap::default();
4451 for argument in &fn_decl.inputs {
4452 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4453 self.visit_ty(&argument.ty);
4455 // No need to resolve return type-- the outer closure return type is
4456 // FunctionRetTy::Default
4458 // Now resolve the inner closure
4460 // No need to resolve arguments: the inner closure has none.
4461 // Resolve the return type:
4462 visit::walk_fn_ret_ty(self, &fn_decl.output);
4464 self.visit_expr(body);
4466 self.ribs[ValueNS].pop();
4469 visit::walk_expr(self, expr);
4474 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4476 ExprKind::Field(_, ident) => {
4477 // FIXME(#6890): Even though you can't treat a method like a
4478 // field, we need to add any trait methods we find that match
4479 // the field name so that we can do some nice error reporting
4480 // later on in typeck.
4481 let traits = self.get_traits_containing_item(ident, ValueNS);
4482 self.trait_map.insert(expr.id, traits);
4484 ExprKind::MethodCall(ref segment, ..) => {
4485 debug!("(recording candidate traits for expr) recording traits for {}",
4487 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4488 self.trait_map.insert(expr.id, traits);
4496 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4497 -> Vec<TraitCandidate> {
4498 debug!("(getting traits containing item) looking for '{}'", ident.name);
4500 let mut found_traits = Vec::new();
4501 // Look for the current trait.
4502 if let Some((module, _)) = self.current_trait_ref {
4503 if self.resolve_ident_in_module(
4504 ModuleOrUniformRoot::Module(module),
4511 let def_id = module.def_id().unwrap();
4512 found_traits.push(TraitCandidate { def_id: def_id, import_ids: smallvec![] });
4516 ident.span = ident.span.modern();
4517 let mut search_module = self.current_module;
4519 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4520 search_module = unwrap_or!(
4521 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4525 if let Some(prelude) = self.prelude {
4526 if !search_module.no_implicit_prelude {
4527 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4534 fn get_traits_in_module_containing_item(&mut self,
4538 found_traits: &mut Vec<TraitCandidate>) {
4539 assert!(ns == TypeNS || ns == ValueNS);
4540 let mut traits = module.traits.borrow_mut();
4541 if traits.is_none() {
4542 let mut collected_traits = Vec::new();
4543 module.for_each_child(|name, ns, binding| {
4544 if ns != TypeNS { return }
4545 match binding.res() {
4546 Res::Def(DefKind::Trait, _) |
4547 Res::Def(DefKind::TraitAlias, _) => collected_traits.push((name, binding)),
4551 *traits = Some(collected_traits.into_boxed_slice());
4554 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4555 // Traits have pseudo-modules that can be used to search for the given ident.
4556 if let Some(module) = binding.module() {
4557 let mut ident = ident;
4558 if ident.span.glob_adjust(
4560 binding.span.ctxt().modern(),
4564 if self.resolve_ident_in_module_unadjusted(
4565 ModuleOrUniformRoot::Module(module),
4571 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4572 let trait_def_id = module.def_id().unwrap();
4573 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4575 } else if let Res::Def(DefKind::TraitAlias, _) = binding.res() {
4576 // For now, just treat all trait aliases as possible candidates, since we don't
4577 // know if the ident is somewhere in the transitive bounds.
4578 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
4579 let trait_def_id = binding.res().def_id();
4580 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
4582 bug!("candidate is not trait or trait alias?")
4587 fn find_transitive_imports(&mut self, mut kind: &NameBindingKind<'_>,
4588 trait_name: Ident) -> SmallVec<[NodeId; 1]> {
4589 let mut import_ids = smallvec![];
4590 while let NameBindingKind::Import { directive, binding, .. } = kind {
4591 self.maybe_unused_trait_imports.insert(directive.id);
4592 self.add_to_glob_map(&directive, trait_name);
4593 import_ids.push(directive.id);
4594 kind = &binding.kind;
4599 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4600 lookup_ident: Ident,
4601 namespace: Namespace,
4602 start_module: &'a ModuleData<'a>,
4604 filter_fn: FilterFn)
4605 -> Vec<ImportSuggestion>
4606 where FilterFn: Fn(Res) -> bool
4608 let mut candidates = Vec::new();
4609 let mut seen_modules = FxHashSet::default();
4610 let not_local_module = crate_name.name != kw::Crate;
4611 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4613 while let Some((in_module,
4615 in_module_is_extern)) = worklist.pop() {
4616 self.populate_module_if_necessary(in_module);
4618 // We have to visit module children in deterministic order to avoid
4619 // instabilities in reported imports (#43552).
4620 in_module.for_each_child_stable(|ident, ns, name_binding| {
4621 // avoid imports entirely
4622 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4623 // avoid non-importable candidates as well
4624 if !name_binding.is_importable() { return; }
4626 // collect results based on the filter function
4627 if ident.name == lookup_ident.name && ns == namespace {
4628 let res = name_binding.res();
4631 let mut segms = path_segments.clone();
4632 if lookup_ident.span.rust_2018() {
4633 // crate-local absolute paths start with `crate::` in edition 2018
4634 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4636 0, ast::PathSegment::from_ident(crate_name)
4640 segms.push(ast::PathSegment::from_ident(ident));
4642 span: name_binding.span,
4645 // the entity is accessible in the following cases:
4646 // 1. if it's defined in the same crate, it's always
4647 // accessible (since private entities can be made public)
4648 // 2. if it's defined in another crate, it's accessible
4649 // only if both the module is public and the entity is
4650 // declared as public (due to pruning, we don't explore
4651 // outside crate private modules => no need to check this)
4652 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4653 let did = match res {
4654 Res::Def(DefKind::Ctor(..), did) => self.parent(did),
4655 _ => res.opt_def_id(),
4657 candidates.push(ImportSuggestion { did, path });
4662 // collect submodules to explore
4663 if let Some(module) = name_binding.module() {
4665 let mut path_segments = path_segments.clone();
4666 path_segments.push(ast::PathSegment::from_ident(ident));
4668 let is_extern_crate_that_also_appears_in_prelude =
4669 name_binding.is_extern_crate() &&
4670 lookup_ident.span.rust_2018();
4672 let is_visible_to_user =
4673 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4675 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4676 // add the module to the lookup
4677 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4678 if seen_modules.insert(module.def_id().unwrap()) {
4679 worklist.push((module, path_segments, is_extern));
4689 /// When name resolution fails, this method can be used to look up candidate
4690 /// entities with the expected name. It allows filtering them using the
4691 /// supplied predicate (which should be used to only accept the types of
4692 /// definitions expected, e.g., traits). The lookup spans across all crates.
4694 /// N.B., the method does not look into imports, but this is not a problem,
4695 /// since we report the definitions (thus, the de-aliased imports).
4696 fn lookup_import_candidates<FilterFn>(&mut self,
4697 lookup_ident: Ident,
4698 namespace: Namespace,
4699 filter_fn: FilterFn)
4700 -> Vec<ImportSuggestion>
4701 where FilterFn: Fn(Res) -> bool
4703 let mut suggestions = self.lookup_import_candidates_from_module(
4704 lookup_ident, namespace, self.graph_root, Ident::with_empty_ctxt(kw::Crate), &filter_fn
4707 if lookup_ident.span.rust_2018() {
4708 let extern_prelude_names = self.extern_prelude.clone();
4709 for (ident, _) in extern_prelude_names.into_iter() {
4710 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4712 let crate_root = self.get_module(DefId {
4714 index: CRATE_DEF_INDEX,
4716 self.populate_module_if_necessary(&crate_root);
4718 suggestions.extend(self.lookup_import_candidates_from_module(
4719 lookup_ident, namespace, crate_root, ident, &filter_fn));
4727 fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
4728 let mut result = None;
4729 let mut seen_modules = FxHashSet::default();
4730 let mut worklist = vec![(self.graph_root, Vec::new())];
4732 while let Some((in_module, path_segments)) = worklist.pop() {
4733 // abort if the module is already found
4734 if result.is_some() { break; }
4736 self.populate_module_if_necessary(in_module);
4738 in_module.for_each_child_stable(|ident, _, name_binding| {
4739 // abort if the module is already found or if name_binding is private external
4740 if result.is_some() || !name_binding.vis.is_visible_locally() {
4743 if let Some(module) = name_binding.module() {
4745 let mut path_segments = path_segments.clone();
4746 path_segments.push(ast::PathSegment::from_ident(ident));
4747 let module_def_id = module.def_id().unwrap();
4748 if module_def_id == def_id {
4750 span: name_binding.span,
4751 segments: path_segments,
4753 result = Some((module, ImportSuggestion { did: Some(def_id), path }));
4755 // add the module to the lookup
4756 if seen_modules.insert(module_def_id) {
4757 worklist.push((module, path_segments));
4767 fn collect_enum_variants(&mut self, def_id: DefId) -> Option<Vec<Path>> {
4768 self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
4769 self.populate_module_if_necessary(enum_module);
4771 let mut variants = Vec::new();
4772 enum_module.for_each_child_stable(|ident, _, name_binding| {
4773 if let Res::Def(DefKind::Variant, _) = name_binding.res() {
4774 let mut segms = enum_import_suggestion.path.segments.clone();
4775 segms.push(ast::PathSegment::from_ident(ident));
4776 variants.push(Path {
4777 span: name_binding.span,
4786 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
4787 debug!("(recording res) recording {:?} for {}", resolution, node_id);
4788 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
4789 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4793 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4795 ast::VisibilityKind::Public => ty::Visibility::Public,
4796 ast::VisibilityKind::Crate(..) => {
4797 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4799 ast::VisibilityKind::Inherited => {
4800 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4802 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4803 // For visibilities we are not ready to provide correct implementation of "uniform
4804 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4805 // On 2015 edition visibilities are resolved as crate-relative by default,
4806 // so we are prepending a root segment if necessary.
4807 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4808 let crate_root = if ident.is_path_segment_keyword() {
4810 } else if ident.span.rust_2018() {
4811 let msg = "relative paths are not supported in visibilities on 2018 edition";
4812 self.session.struct_span_err(ident.span, msg)
4816 format!("crate::{}", path),
4817 Applicability::MaybeIncorrect,
4820 return ty::Visibility::Public;
4822 let ctxt = ident.span.ctxt();
4823 Some(Segment::from_ident(Ident::new(
4824 kw::PathRoot, path.span.shrink_to_lo().with_ctxt(ctxt)
4828 let segments = crate_root.into_iter()
4829 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4830 let res = self.smart_resolve_path_fragment(
4835 PathSource::Visibility,
4836 CrateLint::SimplePath(id),
4838 if res == Res::Err {
4839 ty::Visibility::Public
4841 let vis = ty::Visibility::Restricted(res.def_id());
4842 if self.is_accessible(vis) {
4845 self.session.span_err(path.span, "visibilities can only be restricted \
4846 to ancestor modules");
4847 ty::Visibility::Public
4854 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4855 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4858 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4859 vis.is_accessible_from(module.normal_ancestor_id, self)
4862 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4863 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4864 if !ptr::eq(module, old_module) {
4865 span_bug!(binding.span, "parent module is reset for binding");
4870 fn disambiguate_legacy_vs_modern(
4872 legacy: &'a NameBinding<'a>,
4873 modern: &'a NameBinding<'a>,
4875 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4876 // is disambiguated to mitigate regressions from macro modularization.
4877 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4878 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4879 self.binding_parent_modules.get(&PtrKey(modern))) {
4880 (Some(legacy), Some(modern)) =>
4881 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4882 modern.is_ancestor_of(legacy),
4887 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4888 if b.span.is_dummy() {
4889 let add_built_in = match b.res() {
4890 // These already contain the "built-in" prefix or look bad with it.
4891 Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod => false,
4894 let (built_in, from) = if from_prelude {
4895 ("", " from prelude")
4896 } else if b.is_extern_crate() && !b.is_import() &&
4897 self.session.opts.externs.get(&ident.as_str()).is_some() {
4898 ("", " passed with `--extern`")
4899 } else if add_built_in {
4905 let article = if built_in.is_empty() { b.article() } else { "a" };
4906 format!("{a}{built_in} {thing}{from}",
4907 a = article, thing = b.descr(), built_in = built_in, from = from)
4909 let introduced = if b.is_import() { "imported" } else { "defined" };
4910 format!("the {thing} {introduced} here",
4911 thing = b.descr(), introduced = introduced)
4915 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4916 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4917 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4918 // We have to print the span-less alternative first, otherwise formatting looks bad.
4919 (b2, b1, misc2, misc1, true)
4921 (b1, b2, misc1, misc2, false)
4924 let mut err = struct_span_err!(self.session, ident.span, E0659,
4925 "`{ident}` is ambiguous ({why})",
4926 ident = ident, why = kind.descr());
4927 err.span_label(ident.span, "ambiguous name");
4929 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4930 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4931 let note_msg = format!("`{ident}` could{also} refer to {what}",
4932 ident = ident, also = also, what = what);
4934 let mut help_msgs = Vec::new();
4935 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4936 kind == AmbiguityKind::GlobVsExpanded ||
4937 kind == AmbiguityKind::GlobVsOuter &&
4938 swapped != also.is_empty()) {
4939 help_msgs.push(format!("consider adding an explicit import of \
4940 `{ident}` to disambiguate", ident = ident))
4942 if b.is_extern_crate() && ident.span.rust_2018() {
4943 help_msgs.push(format!(
4944 "use `::{ident}` to refer to this {thing} unambiguously",
4945 ident = ident, thing = b.descr(),
4948 if misc == AmbiguityErrorMisc::SuggestCrate {
4949 help_msgs.push(format!(
4950 "use `crate::{ident}` to refer to this {thing} unambiguously",
4951 ident = ident, thing = b.descr(),
4953 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4954 help_msgs.push(format!(
4955 "use `self::{ident}` to refer to this {thing} unambiguously",
4956 ident = ident, thing = b.descr(),
4960 err.span_note(b.span, ¬e_msg);
4961 for (i, help_msg) in help_msgs.iter().enumerate() {
4962 let or = if i == 0 { "" } else { "or " };
4963 err.help(&format!("{}{}", or, help_msg));
4967 could_refer_to(b1, misc1, "");
4968 could_refer_to(b2, misc2, " also");
4972 fn report_errors(&mut self, krate: &Crate) {
4973 self.report_with_use_injections(krate);
4975 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4976 let msg = "macro-expanded `macro_export` macros from the current crate \
4977 cannot be referred to by absolute paths";
4978 self.session.buffer_lint_with_diagnostic(
4979 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4980 CRATE_NODE_ID, span_use, msg,
4981 lint::builtin::BuiltinLintDiagnostics::
4982 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4986 for ambiguity_error in &self.ambiguity_errors {
4987 self.report_ambiguity_error(ambiguity_error);
4990 let mut reported_spans = FxHashSet::default();
4991 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4992 if reported_spans.insert(dedup_span) {
4993 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4994 binding.descr(), ident.name);
4999 fn report_with_use_injections(&mut self, krate: &Crate) {
5000 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5001 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5002 if !candidates.is_empty() {
5003 show_candidates(&mut err, span, &candidates, better, found_use);
5009 fn report_conflict<'b>(&mut self,
5013 new_binding: &NameBinding<'b>,
5014 old_binding: &NameBinding<'b>) {
5015 // Error on the second of two conflicting names
5016 if old_binding.span.lo() > new_binding.span.lo() {
5017 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5020 let container = match parent.kind {
5021 ModuleKind::Def(DefKind::Mod, _, _) => "module",
5022 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
5023 ModuleKind::Block(..) => "block",
5027 let old_noun = match old_binding.is_import() {
5029 false => "definition",
5032 let new_participle = match new_binding.is_import() {
5037 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5039 if let Some(s) = self.name_already_seen.get(&name) {
5045 let old_kind = match (ns, old_binding.module()) {
5046 (ValueNS, _) => "value",
5047 (MacroNS, _) => "macro",
5048 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5049 (TypeNS, Some(module)) if module.is_normal() => "module",
5050 (TypeNS, Some(module)) if module.is_trait() => "trait",
5051 (TypeNS, _) => "type",
5054 let msg = format!("the name `{}` is defined multiple times", name);
5056 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5057 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5058 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5059 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5060 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5062 _ => match (old_binding.is_import(), new_binding.is_import()) {
5063 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5064 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5065 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5069 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5074 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5076 self.session.source_map().def_span(old_binding.span),
5077 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5080 // See https://github.com/rust-lang/rust/issues/32354
5081 use NameBindingKind::Import;
5082 let directive = match (&new_binding.kind, &old_binding.kind) {
5083 // If there are two imports where one or both have attributes then prefer removing the
5084 // import without attributes.
5085 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5086 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5087 (new.has_attributes || old.has_attributes)
5089 if old.has_attributes {
5090 Some((new, new_binding.span, true))
5092 Some((old, old_binding.span, true))
5095 // Otherwise prioritize the new binding.
5096 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5097 Some((directive, new_binding.span, other.is_import())),
5098 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5099 Some((directive, old_binding.span, other.is_import())),
5103 // Check if the target of the use for both bindings is the same.
5104 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
5105 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5106 let from_item = self.extern_prelude.get(&ident)
5107 .map(|entry| entry.introduced_by_item)
5109 // Only suggest removing an import if both bindings are to the same def, if both spans
5110 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5111 // been introduced by a item.
5112 let should_remove_import = duplicate && !has_dummy_span &&
5113 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5116 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5117 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5118 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5119 // Simple case - remove the entire import. Due to the above match arm, this can
5120 // only be a single use so just remove it entirely.
5121 err.tool_only_span_suggestion(
5122 directive.use_span_with_attributes,
5123 "remove unnecessary import",
5125 Applicability::MaybeIncorrect,
5128 Some((directive, span, _)) =>
5129 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5134 self.name_already_seen.insert(name, span);
5137 /// This function adds a suggestion to change the binding name of a new import that conflicts
5138 /// with an existing import.
5140 /// ```ignore (diagnostic)
5141 /// help: you can use `as` to change the binding name of the import
5143 /// LL | use foo::bar as other_bar;
5144 /// | ^^^^^^^^^^^^^^^^^^^^^
5146 fn add_suggestion_for_rename_of_use(
5148 err: &mut DiagnosticBuilder<'_>,
5150 directive: &ImportDirective<'_>,
5153 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5154 format!("Other{}", name)
5156 format!("other_{}", name)
5159 let mut suggestion = None;
5160 match directive.subclass {
5161 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5162 suggestion = Some(format!("self as {}", suggested_name)),
5163 ImportDirectiveSubclass::SingleImport { source, .. } => {
5164 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5165 .map(|pos| pos as usize) {
5166 if let Ok(snippet) = self.session.source_map()
5167 .span_to_snippet(binding_span) {
5168 if pos <= snippet.len() {
5169 suggestion = Some(format!(
5173 if snippet.ends_with(";") { ";" } else { "" }
5179 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5180 suggestion = Some(format!(
5181 "extern crate {} as {};",
5182 source.unwrap_or(target.name),
5185 _ => unreachable!(),
5188 let rename_msg = "you can use `as` to change the binding name of the import";
5189 if let Some(suggestion) = suggestion {
5190 err.span_suggestion(
5194 Applicability::MaybeIncorrect,
5197 err.span_label(binding_span, rename_msg);
5201 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5202 /// nested. In the following example, this function will be invoked to remove the `a` binding
5203 /// in the second use statement:
5205 /// ```ignore (diagnostic)
5206 /// use issue_52891::a;
5207 /// use issue_52891::{d, a, e};
5210 /// The following suggestion will be added:
5212 /// ```ignore (diagnostic)
5213 /// use issue_52891::{d, a, e};
5214 /// ^-- help: remove unnecessary import
5217 /// If the nested use contains only one import then the suggestion will remove the entire
5220 /// It is expected that the directive provided is a nested import - this isn't checked by the
5221 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5222 /// as characters expected by span manipulations won't be present.
5223 fn add_suggestion_for_duplicate_nested_use(
5225 err: &mut DiagnosticBuilder<'_>,
5226 directive: &ImportDirective<'_>,
5229 assert!(directive.is_nested());
5230 let message = "remove unnecessary import";
5232 // Two examples will be used to illustrate the span manipulations we're doing:
5234 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5235 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5236 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5237 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5239 let (found_closing_brace, span) = find_span_of_binding_until_next_binding(
5240 self.session, binding_span, directive.use_span,
5243 // If there was a closing brace then identify the span to remove any trailing commas from
5244 // previous imports.
5245 if found_closing_brace {
5246 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
5247 err.tool_only_span_suggestion(span, message, String::new(),
5248 Applicability::MaybeIncorrect);
5250 // Remove the entire line if we cannot extend the span back, this indicates a
5251 // `issue_52891::{self}` case.
5252 err.span_suggestion(directive.use_span_with_attributes, message, String::new(),
5253 Applicability::MaybeIncorrect);
5259 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5262 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5263 -> Option<&'a NameBinding<'a>> {
5264 if ident.is_path_segment_keyword() {
5265 // Make sure `self`, `super` etc produce an error when passed to here.
5268 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5269 if let Some(binding) = entry.extern_crate_item {
5270 if !speculative && entry.introduced_by_item {
5271 self.record_use(ident, TypeNS, binding, false);
5275 let crate_id = if !speculative {
5276 self.crate_loader.process_path_extern(ident.name, ident.span)
5277 } else if let Some(crate_id) =
5278 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5283 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5284 self.populate_module_if_necessary(&crate_root);
5285 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5286 .to_name_binding(self.arenas))
5292 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5293 namespace == TypeNS && path.len() == 1 && path[0].ident.name == kw::SelfUpper
5296 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5297 namespace == ValueNS && path.len() == 1 && path[0].ident.name == kw::SelfLower
5300 fn names_to_string(idents: &[Ident]) -> String {
5301 let mut result = String::new();
5302 for (i, ident) in idents.iter()
5303 .filter(|ident| ident.name != kw::PathRoot)
5306 result.push_str("::");
5308 result.push_str(&ident.as_str());
5313 fn path_names_to_string(path: &Path) -> String {
5314 names_to_string(&path.segments.iter()
5315 .map(|seg| seg.ident)
5316 .collect::<Vec<_>>())
5319 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5320 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5321 let variant_path = &suggestion.path;
5322 let variant_path_string = path_names_to_string(variant_path);
5324 let path_len = suggestion.path.segments.len();
5325 let enum_path = ast::Path {
5326 span: suggestion.path.span,
5327 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5329 let enum_path_string = path_names_to_string(&enum_path);
5331 (variant_path_string, enum_path_string)
5334 /// When an entity with a given name is not available in scope, we search for
5335 /// entities with that name in all crates. This method allows outputting the
5336 /// results of this search in a programmer-friendly way
5337 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5338 // This is `None` if all placement locations are inside expansions
5340 candidates: &[ImportSuggestion],
5344 // we want consistent results across executions, but candidates are produced
5345 // by iterating through a hash map, so make sure they are ordered:
5346 let mut path_strings: Vec<_> =
5347 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5348 path_strings.sort();
5350 let better = if better { "better " } else { "" };
5351 let msg_diff = match path_strings.len() {
5352 1 => " is found in another module, you can import it",
5353 _ => "s are found in other modules, you can import them",
5355 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5357 if let Some(span) = span {
5358 for candidate in &mut path_strings {
5359 // produce an additional newline to separate the new use statement
5360 // from the directly following item.
5361 let additional_newline = if found_use {
5366 *candidate = format!("use {};\n{}", candidate, additional_newline);
5369 err.span_suggestions(
5372 path_strings.into_iter(),
5373 Applicability::Unspecified,
5378 for candidate in path_strings {
5380 msg.push_str(&candidate);
5385 /// A somewhat inefficient routine to obtain the name of a module.
5386 fn module_to_string(module: Module<'_>) -> Option<String> {
5387 let mut names = Vec::new();
5389 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5390 if let ModuleKind::Def(.., name) = module.kind {
5391 if let Some(parent) = module.parent {
5392 names.push(Ident::with_empty_ctxt(name));
5393 collect_mod(names, parent);
5396 // danger, shouldn't be ident?
5397 names.push(Ident::from_str("<opaque>"));
5398 collect_mod(names, module.parent.unwrap());
5401 collect_mod(&mut names, module);
5403 if names.is_empty() {
5406 Some(names_to_string(&names.into_iter()
5408 .collect::<Vec<_>>()))
5411 #[derive(Copy, Clone, Debug)]
5413 /// Do not issue the lint.
5416 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5417 /// In this case, we can take the span of that path.
5420 /// This lint comes from a `use` statement. In this case, what we
5421 /// care about really is the *root* `use` statement; e.g., if we
5422 /// have nested things like `use a::{b, c}`, we care about the
5424 UsePath { root_id: NodeId, root_span: Span },
5426 /// This is the "trait item" from a fully qualified path. For example,
5427 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5428 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5429 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5433 fn node_id(&self) -> Option<NodeId> {
5435 CrateLint::No => None,
5436 CrateLint::SimplePath(id) |
5437 CrateLint::UsePath { root_id: id, .. } |
5438 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5443 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }