1 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
2 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
3 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(slice_sort_by_cached_key)]
11 #![recursion_limit="256"]
14 extern crate bitflags;
19 extern crate syntax_pos;
20 extern crate rustc_errors as errors;
24 extern crate rustc_data_structures;
25 extern crate rustc_metadata;
27 pub use rustc::hir::def::{Namespace, PerNS};
29 use self::TypeParameters::*;
32 use rustc::hir::map::{Definitions, DefCollector};
33 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
34 use rustc::middle::cstore::CrateStore;
35 use rustc::session::Session;
37 use rustc::hir::def::*;
38 use rustc::hir::def::Namespace::*;
39 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
40 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
41 use rustc::session::config::nightly_options;
43 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
45 use rustc_metadata::creader::CrateLoader;
46 use rustc_metadata::cstore::CStore;
48 use syntax::source_map::SourceMap;
49 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
50 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
51 use syntax::ext::base::SyntaxExtension;
52 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
53 use syntax::ext::base::MacroKind;
54 use syntax::symbol::{Symbol, keywords};
55 use syntax::util::lev_distance::find_best_match_for_name;
57 use syntax::visit::{self, FnKind, Visitor};
59 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
60 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
61 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
62 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
63 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
66 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
67 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
69 use std::cell::{Cell, RefCell};
70 use std::{cmp, fmt, iter, mem, ptr};
71 use std::collections::BTreeSet;
72 use std::mem::replace;
73 use rustc_data_structures::ptr_key::PtrKey;
74 use rustc_data_structures::sync::Lrc;
76 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
77 use macros::{InvocationData, LegacyBinding, ParentScope};
79 // N.B., this module needs to be declared first so diagnostics are
80 // registered before they are used.
85 mod build_reduced_graph;
88 fn is_known_tool(name: Name) -> bool {
89 ["clippy", "rustfmt"].contains(&&*name.as_str())
99 AbsolutePath(Namespace),
104 /// A free importable items suggested in case of resolution failure.
105 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 enum ResolutionError<'a> {
152 /// error E0401: can't use type parameters from outer function
153 TypeParametersFromOuterFunction(Def),
154 /// error E0403: the name is already used for a type parameter in this type parameter list
155 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
156 /// error E0407: method is not a member of trait
157 MethodNotMemberOfTrait(Name, &'a str),
158 /// error E0437: type is not a member of trait
159 TypeNotMemberOfTrait(Name, &'a str),
160 /// error E0438: const is not a member of trait
161 ConstNotMemberOfTrait(Name, &'a str),
162 /// error E0408: variable `{}` is not bound in all patterns
163 VariableNotBoundInPattern(&'a BindingError),
164 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
165 VariableBoundWithDifferentMode(Name, Span),
166 /// error E0415: identifier is bound more than once in this parameter list
167 IdentifierBoundMoreThanOnceInParameterList(&'a str),
168 /// error E0416: identifier is bound more than once in the same pattern
169 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
170 /// error E0426: use of undeclared label
171 UndeclaredLabel(&'a str, Option<Name>),
172 /// error E0429: `self` imports are only allowed within a { } list
173 SelfImportsOnlyAllowedWithin,
174 /// error E0430: `self` import can only appear once in the list
175 SelfImportCanOnlyAppearOnceInTheList,
176 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
177 SelfImportOnlyInImportListWithNonEmptyPrefix,
178 /// error E0433: failed to resolve
179 FailedToResolve(&'a str),
180 /// error E0434: can't capture dynamic environment in a fn item
181 CannotCaptureDynamicEnvironmentInFnItem,
182 /// error E0435: attempt to use a non-constant value in a constant
183 AttemptToUseNonConstantValueInConstant,
184 /// error E0530: X bindings cannot shadow Ys
185 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
186 /// error E0128: type parameters with a default cannot use forward declared identifiers
187 ForwardDeclaredTyParam,
190 /// Combines an error with provided span and emits it
192 /// This takes the error provided, combines it with the span and any additional spans inside the
193 /// error and emits it.
194 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
196 resolution_error: ResolutionError<'a>) {
197 resolve_struct_error(resolver, span, resolution_error).emit();
200 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
202 resolution_error: ResolutionError<'a>)
203 -> DiagnosticBuilder<'sess> {
204 match resolution_error {
205 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
206 let mut err = struct_span_err!(resolver.session,
209 "can't use type parameters from outer function");
210 err.span_label(span, "use of type variable from outer function");
212 let cm = resolver.session.source_map();
214 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
215 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
216 resolver.definitions.opt_span(def_id)
219 reduce_impl_span_to_impl_keyword(cm, impl_span),
220 "`Self` type implicitly declared here, by this `impl`",
223 match (maybe_trait_defid, maybe_impl_defid) {
225 err.span_label(span, "can't use `Self` here");
228 err.span_label(span, "use a type here instead");
230 (None, None) => bug!("`impl` without trait nor type?"),
234 Def::TyParam(typaram_defid) => {
235 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
236 err.span_label(typaram_span, "type variable from outer function");
240 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
245 // Try to retrieve the span of the function signature and generate a new message with
246 // a local type parameter
247 let sugg_msg = "try using a local type parameter instead";
248 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
249 // Suggest the modification to the user
254 Applicability::MachineApplicable,
256 } else if let Some(sp) = cm.generate_fn_name_span(span) {
257 err.span_label(sp, "try adding a local type parameter in this method instead");
259 err.help("try using a local type parameter instead");
264 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
265 let mut err = struct_span_err!(resolver.session,
268 "the name `{}` is already used for a type parameter \
269 in this type parameter list",
271 err.span_label(span, "already used");
272 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
275 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
276 let mut err = struct_span_err!(resolver.session,
279 "method `{}` is not a member of trait `{}`",
282 err.span_label(span, format!("not a member of trait `{}`", trait_));
285 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
286 let mut err = struct_span_err!(resolver.session,
289 "type `{}` is not a member of trait `{}`",
292 err.span_label(span, format!("not a member of trait `{}`", trait_));
295 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
296 let mut err = struct_span_err!(resolver.session,
299 "const `{}` is not a member of trait `{}`",
302 err.span_label(span, format!("not a member of trait `{}`", trait_));
305 ResolutionError::VariableNotBoundInPattern(binding_error) => {
306 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
307 let msp = MultiSpan::from_spans(target_sp.clone());
308 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
309 let mut err = resolver.session.struct_span_err_with_code(
312 DiagnosticId::Error("E0408".into()),
314 for sp in target_sp {
315 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
317 let origin_sp = binding_error.origin.iter().cloned();
318 for sp in origin_sp {
319 err.span_label(sp, "variable not in all patterns");
323 ResolutionError::VariableBoundWithDifferentMode(variable_name,
324 first_binding_span) => {
325 let mut err = struct_span_err!(resolver.session,
328 "variable `{}` is bound in inconsistent \
329 ways within the same match arm",
331 err.span_label(span, "bound in different ways");
332 err.span_label(first_binding_span, "first binding");
335 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
336 let mut err = struct_span_err!(resolver.session,
339 "identifier `{}` is bound more than once in this parameter list",
341 err.span_label(span, "used as parameter more than once");
344 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
345 let mut err = struct_span_err!(resolver.session,
348 "identifier `{}` is bound more than once in the same pattern",
350 err.span_label(span, "used in a pattern more than once");
353 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
354 let mut err = struct_span_err!(resolver.session,
357 "use of undeclared label `{}`",
359 if let Some(lev_candidate) = lev_candidate {
360 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
362 err.span_label(span, format!("undeclared label `{}`", name));
366 ResolutionError::SelfImportsOnlyAllowedWithin => {
367 struct_span_err!(resolver.session,
371 "`self` imports are only allowed within a { } list")
373 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
374 let mut err = struct_span_err!(resolver.session, span, E0430,
375 "`self` import can only appear once in an import list");
376 err.span_label(span, "can only appear once in an import list");
379 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
380 let mut err = struct_span_err!(resolver.session, span, E0431,
381 "`self` import can only appear in an import list with \
382 a non-empty prefix");
383 err.span_label(span, "can only appear in an import list with a non-empty prefix");
386 ResolutionError::FailedToResolve(msg) => {
387 let mut err = struct_span_err!(resolver.session, span, E0433,
388 "failed to resolve: {}", msg);
389 err.span_label(span, msg);
392 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
393 let mut err = struct_span_err!(resolver.session,
397 "can't capture dynamic environment in a fn item");
398 err.help("use the `|| { ... }` closure form instead");
401 ResolutionError::AttemptToUseNonConstantValueInConstant => {
402 let mut err = struct_span_err!(resolver.session, span, E0435,
403 "attempt to use a non-constant value in a constant");
404 err.span_label(span, "non-constant value");
407 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
408 let shadows_what = binding.descr();
409 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
410 what_binding, shadows_what);
411 err.span_label(span, format!("cannot be named the same as {} {}",
412 binding.article(), shadows_what));
413 let participle = if binding.is_import() { "imported" } else { "defined" };
414 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
415 err.span_label(binding.span, msg);
418 ResolutionError::ForwardDeclaredTyParam => {
419 let mut err = struct_span_err!(resolver.session, span, E0128,
420 "type parameters with a default cannot use \
421 forward declared identifiers");
423 span, "defaulted type parameters cannot be forward declared".to_string());
429 /// Adjust the impl span so that just the `impl` keyword is taken by removing
430 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
431 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
433 /// Attention: The method used is very fragile since it essentially duplicates the work of the
434 /// parser. If you need to use this function or something similar, please consider updating the
435 /// source_map functions and this function to something more robust.
436 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
437 let impl_span = cm.span_until_char(impl_span, '<');
438 let impl_span = cm.span_until_whitespace(impl_span);
442 #[derive(Copy, Clone, Debug)]
445 binding_mode: BindingMode,
448 /// Map from the name in a pattern to its binding mode.
449 type BindingMap = FxHashMap<Ident, BindingInfo>;
451 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
462 fn descr(self) -> &'static str {
464 PatternSource::Match => "match binding",
465 PatternSource::IfLet => "if let binding",
466 PatternSource::WhileLet => "while let binding",
467 PatternSource::Let => "let binding",
468 PatternSource::For => "for binding",
469 PatternSource::FnParam => "function parameter",
474 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
475 enum AliasPossibility {
480 #[derive(Copy, Clone, Debug)]
481 enum PathSource<'a> {
482 // Type paths `Path`.
484 // Trait paths in bounds or impls.
485 Trait(AliasPossibility),
486 // Expression paths `path`, with optional parent context.
487 Expr(Option<&'a Expr>),
488 // Paths in path patterns `Path`.
490 // Paths in struct expressions and patterns `Path { .. }`.
492 // Paths in tuple struct patterns `Path(..)`.
494 // `m::A::B` in `<T as m::A>::B::C`.
495 TraitItem(Namespace),
496 // Path in `pub(path)`
500 impl<'a> PathSource<'a> {
501 fn namespace(self) -> Namespace {
503 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
504 PathSource::Visibility => TypeNS,
505 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
506 PathSource::TraitItem(ns) => ns,
510 fn global_by_default(self) -> bool {
512 PathSource::Visibility => true,
513 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
514 PathSource::Struct | PathSource::TupleStruct |
515 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
519 fn defer_to_typeck(self) -> bool {
521 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
522 PathSource::Struct | PathSource::TupleStruct => true,
523 PathSource::Trait(_) | PathSource::TraitItem(..) |
524 PathSource::Visibility => false,
528 fn descr_expected(self) -> &'static str {
530 PathSource::Type => "type",
531 PathSource::Trait(_) => "trait",
532 PathSource::Pat => "unit struct/variant or constant",
533 PathSource::Struct => "struct, variant or union type",
534 PathSource::TupleStruct => "tuple struct/variant",
535 PathSource::Visibility => "module",
536 PathSource::TraitItem(ns) => match ns {
537 TypeNS => "associated type",
538 ValueNS => "method or associated constant",
539 MacroNS => bug!("associated macro"),
541 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
542 // "function" here means "anything callable" rather than `Def::Fn`,
543 // this is not precise but usually more helpful than just "value".
544 Some(&ExprKind::Call(..)) => "function",
550 fn is_expected(self, def: Def) -> bool {
552 PathSource::Type => match def {
553 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
554 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
555 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
556 Def::SelfTy(..) | Def::Existential(..) |
557 Def::ForeignTy(..) => true,
560 PathSource::Trait(AliasPossibility::No) => match def {
561 Def::Trait(..) => true,
564 PathSource::Trait(AliasPossibility::Maybe) => match def {
565 Def::Trait(..) => true,
566 Def::TraitAlias(..) => true,
569 PathSource::Expr(..) => match def {
570 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
571 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
572 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
573 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
574 Def::SelfCtor(..) => true,
577 PathSource::Pat => match def {
578 Def::StructCtor(_, CtorKind::Const) |
579 Def::VariantCtor(_, CtorKind::Const) |
580 Def::Const(..) | Def::AssociatedConst(..) |
581 Def::SelfCtor(..) => true,
584 PathSource::TupleStruct => match def {
585 Def::StructCtor(_, CtorKind::Fn) |
586 Def::VariantCtor(_, CtorKind::Fn) |
587 Def::SelfCtor(..) => true,
590 PathSource::Struct => match def {
591 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
592 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
595 PathSource::TraitItem(ns) => match def {
596 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
597 Def::AssociatedTy(..) if ns == TypeNS => true,
600 PathSource::Visibility => match def {
601 Def::Mod(..) => true,
607 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
608 __diagnostic_used!(E0404);
609 __diagnostic_used!(E0405);
610 __diagnostic_used!(E0412);
611 __diagnostic_used!(E0422);
612 __diagnostic_used!(E0423);
613 __diagnostic_used!(E0425);
614 __diagnostic_used!(E0531);
615 __diagnostic_used!(E0532);
616 __diagnostic_used!(E0573);
617 __diagnostic_used!(E0574);
618 __diagnostic_used!(E0575);
619 __diagnostic_used!(E0576);
620 __diagnostic_used!(E0577);
621 __diagnostic_used!(E0578);
622 match (self, has_unexpected_resolution) {
623 (PathSource::Trait(_), true) => "E0404",
624 (PathSource::Trait(_), false) => "E0405",
625 (PathSource::Type, true) => "E0573",
626 (PathSource::Type, false) => "E0412",
627 (PathSource::Struct, true) => "E0574",
628 (PathSource::Struct, false) => "E0422",
629 (PathSource::Expr(..), true) => "E0423",
630 (PathSource::Expr(..), false) => "E0425",
631 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
632 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
633 (PathSource::TraitItem(..), true) => "E0575",
634 (PathSource::TraitItem(..), false) => "E0576",
635 (PathSource::Visibility, true) => "E0577",
636 (PathSource::Visibility, false) => "E0578",
641 // A minimal representation of a path segment. We use this in resolve because
642 // we synthesize 'path segments' which don't have the rest of an AST or HIR
644 #[derive(Clone, Copy, Debug)]
651 fn from_path(path: &Path) -> Vec<Segment> {
652 path.segments.iter().map(|s| s.into()).collect()
655 fn from_ident(ident: Ident) -> Segment {
662 fn names_to_string(segments: &[Segment]) -> String {
663 names_to_string(&segments.iter()
664 .map(|seg| seg.ident)
665 .collect::<Vec<_>>())
669 impl<'a> From<&'a ast::PathSegment> for Segment {
670 fn from(seg: &'a ast::PathSegment) -> Segment {
678 struct UsePlacementFinder {
679 target_module: NodeId,
684 impl UsePlacementFinder {
685 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
686 let mut finder = UsePlacementFinder {
691 visit::walk_crate(&mut finder, krate);
692 (finder.span, finder.found_use)
696 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
699 module: &'tcx ast::Mod,
701 _: &[ast::Attribute],
704 if self.span.is_some() {
707 if node_id != self.target_module {
708 visit::walk_mod(self, module);
711 // find a use statement
712 for item in &module.items {
714 ItemKind::Use(..) => {
715 // don't suggest placing a use before the prelude
716 // import or other generated ones
717 if item.span.ctxt().outer().expn_info().is_none() {
718 self.span = Some(item.span.shrink_to_lo());
719 self.found_use = true;
723 // don't place use before extern crate
724 ItemKind::ExternCrate(_) => {}
725 // but place them before the first other item
726 _ => if self.span.map_or(true, |span| item.span < span ) {
727 if item.span.ctxt().outer().expn_info().is_none() {
728 // don't insert between attributes and an item
729 if item.attrs.is_empty() {
730 self.span = Some(item.span.shrink_to_lo());
732 // find the first attribute on the item
733 for attr in &item.attrs {
734 if self.span.map_or(true, |span| attr.span < span) {
735 self.span = Some(attr.span.shrink_to_lo());
746 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
747 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
748 fn visit_item(&mut self, item: &'tcx Item) {
749 self.resolve_item(item);
751 fn visit_arm(&mut self, arm: &'tcx Arm) {
752 self.resolve_arm(arm);
754 fn visit_block(&mut self, block: &'tcx Block) {
755 self.resolve_block(block);
757 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
758 self.with_constant_rib(|this| {
759 visit::walk_anon_const(this, constant);
762 fn visit_expr(&mut self, expr: &'tcx Expr) {
763 self.resolve_expr(expr, None);
765 fn visit_local(&mut self, local: &'tcx Local) {
766 self.resolve_local(local);
768 fn visit_ty(&mut self, ty: &'tcx Ty) {
770 TyKind::Path(ref qself, ref path) => {
771 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
773 TyKind::ImplicitSelf => {
774 let self_ty = keywords::SelfUpper.ident();
775 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
776 .map_or(Def::Err, |d| d.def());
777 self.record_def(ty.id, PathResolution::new(def));
781 visit::walk_ty(self, ty);
783 fn visit_poly_trait_ref(&mut self,
784 tref: &'tcx ast::PolyTraitRef,
785 m: &'tcx ast::TraitBoundModifier) {
786 self.smart_resolve_path(tref.trait_ref.ref_id, None,
787 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
788 visit::walk_poly_trait_ref(self, tref, m);
790 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
791 let type_parameters = match foreign_item.node {
792 ForeignItemKind::Fn(_, ref generics) => {
793 HasTypeParameters(generics, ItemRibKind)
795 ForeignItemKind::Static(..) => NoTypeParameters,
796 ForeignItemKind::Ty => NoTypeParameters,
797 ForeignItemKind::Macro(..) => NoTypeParameters,
799 self.with_type_parameter_rib(type_parameters, |this| {
800 visit::walk_foreign_item(this, foreign_item);
803 fn visit_fn(&mut self,
804 function_kind: FnKind<'tcx>,
805 declaration: &'tcx FnDecl,
809 let (rib_kind, asyncness) = match function_kind {
810 FnKind::ItemFn(_, ref header, ..) =>
811 (ItemRibKind, header.asyncness),
812 FnKind::Method(_, ref sig, _, _) =>
813 (TraitOrImplItemRibKind, sig.header.asyncness),
814 FnKind::Closure(_) =>
815 // Async closures aren't resolved through `visit_fn`-- they're
816 // processed separately
817 (ClosureRibKind(node_id), IsAsync::NotAsync),
820 // Create a value rib for the function.
821 self.ribs[ValueNS].push(Rib::new(rib_kind));
823 // Create a label rib for the function.
824 self.label_ribs.push(Rib::new(rib_kind));
826 // Add each argument to the rib.
827 let mut bindings_list = FxHashMap::default();
828 for argument in &declaration.inputs {
829 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
831 self.visit_ty(&argument.ty);
833 debug!("(resolving function) recorded argument");
835 visit::walk_fn_ret_ty(self, &declaration.output);
837 // Resolve the function body, potentially inside the body of an async closure
838 if let IsAsync::Async { closure_id, .. } = asyncness {
839 let rib_kind = ClosureRibKind(closure_id);
840 self.ribs[ValueNS].push(Rib::new(rib_kind));
841 self.label_ribs.push(Rib::new(rib_kind));
844 match function_kind {
845 FnKind::ItemFn(.., body) |
846 FnKind::Method(.., body) => {
847 self.visit_block(body);
849 FnKind::Closure(body) => {
850 self.visit_expr(body);
854 // Leave the body of the async closure
855 if asyncness.is_async() {
856 self.label_ribs.pop();
857 self.ribs[ValueNS].pop();
860 debug!("(resolving function) leaving function");
862 self.label_ribs.pop();
863 self.ribs[ValueNS].pop();
865 fn visit_generics(&mut self, generics: &'tcx Generics) {
866 // For type parameter defaults, we have to ban access
867 // to following type parameters, as the Substs can only
868 // provide previous type parameters as they're built. We
869 // put all the parameters on the ban list and then remove
870 // them one by one as they are processed and become available.
871 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
872 let mut found_default = false;
873 default_ban_rib.bindings.extend(generics.params.iter()
874 .filter_map(|param| match param.kind {
875 GenericParamKind::Lifetime { .. } => None,
876 GenericParamKind::Type { ref default, .. } => {
877 found_default |= default.is_some();
879 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
886 for param in &generics.params {
888 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
889 GenericParamKind::Type { ref default, .. } => {
890 for bound in ¶m.bounds {
891 self.visit_param_bound(bound);
894 if let Some(ref ty) = default {
895 self.ribs[TypeNS].push(default_ban_rib);
897 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
900 // Allow all following defaults to refer to this type parameter.
901 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
905 for p in &generics.where_clause.predicates {
906 self.visit_where_predicate(p);
911 #[derive(Copy, Clone)]
912 enum TypeParameters<'a, 'b> {
914 HasTypeParameters(// Type parameters.
917 // The kind of the rib used for type parameters.
921 /// The rib kind controls the translation of local
922 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
923 #[derive(Copy, Clone, Debug)]
925 /// No translation needs to be applied.
928 /// We passed through a closure scope at the given node ID.
929 /// Translate upvars as appropriate.
930 ClosureRibKind(NodeId /* func id */),
932 /// We passed through an impl or trait and are now in one of its
933 /// methods or associated types. Allow references to ty params that impl or trait
934 /// binds. Disallow any other upvars (including other ty params that are
936 TraitOrImplItemRibKind,
938 /// We passed through an item scope. Disallow upvars.
941 /// We're in a constant item. Can't refer to dynamic stuff.
944 /// We passed through a module.
945 ModuleRibKind(Module<'a>),
947 /// We passed through a `macro_rules!` statement
948 MacroDefinition(DefId),
950 /// All bindings in this rib are type parameters that can't be used
951 /// from the default of a type parameter because they're not declared
952 /// before said type parameter. Also see the `visit_generics` override.
953 ForwardTyParamBanRibKind,
958 /// A rib represents a scope names can live in. Note that these appear in many places, not just
959 /// around braces. At any place where the list of accessible names (of the given namespace)
960 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
961 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
964 /// Different [rib kinds](enum.RibKind) are transparent for different names.
966 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
967 /// resolving, the name is looked up from inside out.
970 bindings: FxHashMap<Ident, Def>,
975 fn new(kind: RibKind<'a>) -> Rib<'a> {
977 bindings: Default::default(),
983 /// An intermediate resolution result.
985 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
986 /// items are visible in their whole block, while defs only from the place they are defined
988 enum LexicalScopeBinding<'a> {
989 Item(&'a NameBinding<'a>),
993 impl<'a> LexicalScopeBinding<'a> {
994 fn item(self) -> Option<&'a NameBinding<'a>> {
996 LexicalScopeBinding::Item(binding) => Some(binding),
1001 fn def(self) -> Def {
1003 LexicalScopeBinding::Item(binding) => binding.def(),
1004 LexicalScopeBinding::Def(def) => def,
1009 #[derive(Copy, Clone, Debug)]
1010 enum ModuleOrUniformRoot<'a> {
1014 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1015 CrateRootAndExternPrelude,
1017 /// Virtual module that denotes resolution in extern prelude.
1018 /// Used for paths starting with `::` on 2018 edition.
1021 /// Virtual module that denotes resolution in current scope.
1022 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1023 /// are always split into two parts, the first of which should be some kind of module.
1027 impl ModuleOrUniformRoot<'_> {
1028 fn same_def(lhs: Self, rhs: Self) -> bool {
1030 (ModuleOrUniformRoot::Module(lhs),
1031 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1032 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1033 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1034 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1035 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1041 #[derive(Clone, Debug)]
1042 enum PathResult<'a> {
1043 Module(ModuleOrUniformRoot<'a>),
1044 NonModule(PathResolution),
1046 Failed(Span, String, bool /* is the error from the last segment? */),
1050 /// An anonymous module, eg. just a block.
1054 /// fn f() {} // (1)
1055 /// { // This is an anonymous module
1056 /// f(); // This resolves to (2) as we are inside the block.
1057 /// fn f() {} // (2)
1059 /// f(); // Resolves to (1)
1063 /// Any module with a name.
1067 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1068 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1073 /// One node in the tree of modules.
1074 pub struct ModuleData<'a> {
1075 parent: Option<Module<'a>>,
1078 // The def id of the closest normal module (`mod`) ancestor (including this module).
1079 normal_ancestor_id: DefId,
1081 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1082 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1083 Option<&'a NameBinding<'a>>)>>,
1084 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1086 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1088 // Macro invocations that can expand into items in this module.
1089 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1091 no_implicit_prelude: bool,
1093 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1094 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1096 // Used to memoize the traits in this module for faster searches through all traits in scope.
1097 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1099 // Whether this module is populated. If not populated, any attempt to
1100 // access the children must be preceded with a
1101 // `populate_module_if_necessary` call.
1102 populated: Cell<bool>,
1104 /// Span of the module itself. Used for error reporting.
1110 type Module<'a> = &'a ModuleData<'a>;
1112 impl<'a> ModuleData<'a> {
1113 fn new(parent: Option<Module<'a>>,
1115 normal_ancestor_id: DefId,
1117 span: Span) -> Self {
1122 resolutions: Default::default(),
1123 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1124 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1125 builtin_attrs: RefCell::new(Vec::new()),
1126 unresolved_invocations: Default::default(),
1127 no_implicit_prelude: false,
1128 glob_importers: RefCell::new(Vec::new()),
1129 globs: RefCell::new(Vec::new()),
1130 traits: RefCell::new(None),
1131 populated: Cell::new(normal_ancestor_id.is_local()),
1137 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1138 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1139 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1143 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1144 let resolutions = self.resolutions.borrow();
1145 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1146 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1147 for &(&(ident, ns), &resolution) in resolutions.iter() {
1148 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1152 fn def(&self) -> Option<Def> {
1154 ModuleKind::Def(def, _) => Some(def),
1159 fn def_id(&self) -> Option<DefId> {
1160 self.def().as_ref().map(Def::def_id)
1163 // `self` resolves to the first module ancestor that `is_normal`.
1164 fn is_normal(&self) -> bool {
1166 ModuleKind::Def(Def::Mod(_), _) => true,
1171 fn is_trait(&self) -> bool {
1173 ModuleKind::Def(Def::Trait(_), _) => true,
1178 fn nearest_item_scope(&'a self) -> Module<'a> {
1179 if self.is_trait() { self.parent.unwrap() } else { self }
1182 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1183 while !ptr::eq(self, other) {
1184 if let Some(parent) = other.parent {
1194 impl<'a> fmt::Debug for ModuleData<'a> {
1195 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1196 write!(f, "{:?}", self.def())
1200 /// Records a possibly-private value, type, or module definition.
1201 #[derive(Clone, Debug)]
1202 pub struct NameBinding<'a> {
1203 kind: NameBindingKind<'a>,
1204 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1207 vis: ty::Visibility,
1210 pub trait ToNameBinding<'a> {
1211 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1214 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1215 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1220 #[derive(Clone, Debug)]
1221 enum NameBindingKind<'a> {
1222 Def(Def, /* is_macro_export */ bool),
1225 binding: &'a NameBinding<'a>,
1226 directive: &'a ImportDirective<'a>,
1231 impl<'a> NameBindingKind<'a> {
1232 /// Is this a name binding of a import?
1233 fn is_import(&self) -> bool {
1235 NameBindingKind::Import { .. } => true,
1241 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1243 struct UseError<'a> {
1244 err: DiagnosticBuilder<'a>,
1245 /// Attach `use` statements for these candidates
1246 candidates: Vec<ImportSuggestion>,
1247 /// The node id of the module to place the use statements in
1249 /// Whether the diagnostic should state that it's "better"
1253 #[derive(Clone, Copy, PartialEq, Debug)]
1254 enum AmbiguityKind {
1259 LegacyHelperVsPrelude,
1264 MoreExpandedVsOuter,
1267 impl AmbiguityKind {
1268 fn descr(self) -> &'static str {
1270 AmbiguityKind::Import =>
1271 "name vs any other name during import resolution",
1272 AmbiguityKind::AbsolutePath =>
1273 "name in the crate root vs extern crate during absolute path resolution",
1274 AmbiguityKind::BuiltinAttr =>
1275 "built-in attribute vs any other name",
1276 AmbiguityKind::DeriveHelper =>
1277 "derive helper attribute vs any other name",
1278 AmbiguityKind::LegacyHelperVsPrelude =>
1279 "legacy plugin helper attribute vs name from prelude",
1280 AmbiguityKind::LegacyVsModern =>
1281 "`macro_rules` vs non-`macro_rules` from other module",
1282 AmbiguityKind::GlobVsOuter =>
1283 "glob import vs any other name from outer scope during import/macro resolution",
1284 AmbiguityKind::GlobVsGlob =>
1285 "glob import vs glob import in the same module",
1286 AmbiguityKind::GlobVsExpanded =>
1287 "glob import vs macro-expanded name in the same \
1288 module during import/macro resolution",
1289 AmbiguityKind::MoreExpandedVsOuter =>
1290 "macro-expanded name vs less macro-expanded name \
1291 from outer scope during import/macro resolution",
1296 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1297 #[derive(Clone, Copy, PartialEq)]
1298 enum AmbiguityErrorMisc {
1305 struct AmbiguityError<'a> {
1306 kind: AmbiguityKind,
1308 b1: &'a NameBinding<'a>,
1309 b2: &'a NameBinding<'a>,
1310 misc1: AmbiguityErrorMisc,
1311 misc2: AmbiguityErrorMisc,
1314 impl<'a> NameBinding<'a> {
1315 fn module(&self) -> Option<Module<'a>> {
1317 NameBindingKind::Module(module) => Some(module),
1318 NameBindingKind::Import { binding, .. } => binding.module(),
1323 fn def(&self) -> Def {
1325 NameBindingKind::Def(def, _) => def,
1326 NameBindingKind::Module(module) => module.def().unwrap(),
1327 NameBindingKind::Import { binding, .. } => binding.def(),
1331 fn is_ambiguity(&self) -> bool {
1332 self.ambiguity.is_some() || match self.kind {
1333 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1338 // We sometimes need to treat variants as `pub` for backwards compatibility
1339 fn pseudo_vis(&self) -> ty::Visibility {
1340 if self.is_variant() && self.def().def_id().is_local() {
1341 ty::Visibility::Public
1347 fn is_variant(&self) -> bool {
1349 NameBindingKind::Def(Def::Variant(..), _) |
1350 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1355 fn is_extern_crate(&self) -> bool {
1357 NameBindingKind::Import {
1358 directive: &ImportDirective {
1359 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1362 NameBindingKind::Module(
1363 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1364 ) => def_id.index == CRATE_DEF_INDEX,
1369 fn is_import(&self) -> bool {
1371 NameBindingKind::Import { .. } => true,
1376 fn is_glob_import(&self) -> bool {
1378 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1383 fn is_importable(&self) -> bool {
1385 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1390 fn is_macro_def(&self) -> bool {
1392 NameBindingKind::Def(Def::Macro(..), _) => true,
1397 fn macro_kind(&self) -> Option<MacroKind> {
1399 Def::Macro(_, kind) => Some(kind),
1400 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1405 fn descr(&self) -> &'static str {
1406 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1409 fn article(&self) -> &'static str {
1410 if self.is_extern_crate() { "an" } else { self.def().article() }
1413 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1414 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1415 // Then this function returns `true` if `self` may emerge from a macro *after* that
1416 // in some later round and screw up our previously found resolution.
1417 // See more detailed explanation in
1418 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1419 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1420 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1421 // Expansions are partially ordered, so "may appear after" is an inversion of
1422 // "certainly appears before or simultaneously" and includes unordered cases.
1423 let self_parent_expansion = self.expansion;
1424 let other_parent_expansion = binding.expansion;
1425 let certainly_before_other_or_simultaneously =
1426 other_parent_expansion.is_descendant_of(self_parent_expansion);
1427 let certainly_before_invoc_or_simultaneously =
1428 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1429 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1433 /// Interns the names of the primitive types.
1435 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1436 /// special handling, since they have no place of origin.
1438 struct PrimitiveTypeTable {
1439 primitive_types: FxHashMap<Name, PrimTy>,
1442 impl PrimitiveTypeTable {
1443 fn new() -> PrimitiveTypeTable {
1444 let mut table = PrimitiveTypeTable::default();
1446 table.intern("bool", Bool);
1447 table.intern("char", Char);
1448 table.intern("f32", Float(FloatTy::F32));
1449 table.intern("f64", Float(FloatTy::F64));
1450 table.intern("isize", Int(IntTy::Isize));
1451 table.intern("i8", Int(IntTy::I8));
1452 table.intern("i16", Int(IntTy::I16));
1453 table.intern("i32", Int(IntTy::I32));
1454 table.intern("i64", Int(IntTy::I64));
1455 table.intern("i128", Int(IntTy::I128));
1456 table.intern("str", Str);
1457 table.intern("usize", Uint(UintTy::Usize));
1458 table.intern("u8", Uint(UintTy::U8));
1459 table.intern("u16", Uint(UintTy::U16));
1460 table.intern("u32", Uint(UintTy::U32));
1461 table.intern("u64", Uint(UintTy::U64));
1462 table.intern("u128", Uint(UintTy::U128));
1466 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1467 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1471 #[derive(Debug, Default, Clone)]
1472 pub struct ExternPreludeEntry<'a> {
1473 extern_crate_item: Option<&'a NameBinding<'a>>,
1474 pub introduced_by_item: bool,
1477 /// The main resolver class.
1479 /// This is the visitor that walks the whole crate.
1480 pub struct Resolver<'a> {
1481 session: &'a Session,
1484 pub definitions: Definitions,
1486 graph_root: Module<'a>,
1488 prelude: Option<Module<'a>>,
1489 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1491 /// n.b. This is used only for better diagnostics, not name resolution itself.
1492 has_self: FxHashSet<DefId>,
1494 /// Names of fields of an item `DefId` accessible with dot syntax.
1495 /// Used for hints during error reporting.
1496 field_names: FxHashMap<DefId, Vec<Name>>,
1498 /// All imports known to succeed or fail.
1499 determined_imports: Vec<&'a ImportDirective<'a>>,
1501 /// All non-determined imports.
1502 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1504 /// The module that represents the current item scope.
1505 current_module: Module<'a>,
1507 /// The current set of local scopes for types and values.
1508 /// FIXME #4948: Reuse ribs to avoid allocation.
1509 ribs: PerNS<Vec<Rib<'a>>>,
1511 /// The current set of local scopes, for labels.
1512 label_ribs: Vec<Rib<'a>>,
1514 /// The trait that the current context can refer to.
1515 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1517 /// The current self type if inside an impl (used for better errors).
1518 current_self_type: Option<Ty>,
1520 /// The current self item if inside an ADT (used for better errors).
1521 current_self_item: Option<NodeId>,
1523 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1524 /// We are resolving a last import segment during import validation.
1525 last_import_segment: bool,
1526 /// This binding should be ignored during in-module resolution, so that we don't get
1527 /// "self-confirming" import resolutions during import validation.
1528 blacklisted_binding: Option<&'a NameBinding<'a>>,
1530 /// The idents for the primitive types.
1531 primitive_type_table: PrimitiveTypeTable,
1534 import_map: ImportMap,
1535 pub freevars: FreevarMap,
1536 freevars_seen: NodeMap<NodeMap<usize>>,
1537 pub export_map: ExportMap,
1538 pub trait_map: TraitMap,
1540 /// A map from nodes to anonymous modules.
1541 /// Anonymous modules are pseudo-modules that are implicitly created around items
1542 /// contained within blocks.
1544 /// For example, if we have this:
1552 /// There will be an anonymous module created around `g` with the ID of the
1553 /// entry block for `f`.
1554 block_map: NodeMap<Module<'a>>,
1555 module_map: FxHashMap<DefId, Module<'a>>,
1556 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1557 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1559 /// Maps glob imports to the names of items actually imported.
1560 pub glob_map: GlobMap,
1562 used_imports: FxHashSet<(NodeId, Namespace)>,
1563 pub maybe_unused_trait_imports: NodeSet,
1564 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1566 /// A list of labels as of yet unused. Labels will be removed from this map when
1567 /// they are used (in a `break` or `continue` statement)
1568 pub unused_labels: FxHashMap<NodeId, Span>,
1570 /// privacy errors are delayed until the end in order to deduplicate them
1571 privacy_errors: Vec<PrivacyError<'a>>,
1572 /// ambiguity errors are delayed for deduplication
1573 ambiguity_errors: Vec<AmbiguityError<'a>>,
1574 /// `use` injections are delayed for better placement and deduplication
1575 use_injections: Vec<UseError<'a>>,
1576 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1577 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1579 arenas: &'a ResolverArenas<'a>,
1580 dummy_binding: &'a NameBinding<'a>,
1582 crate_loader: &'a mut CrateLoader<'a>,
1583 macro_names: FxHashSet<Ident>,
1584 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1585 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1586 pub all_macros: FxHashMap<Name, Def>,
1587 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1588 macro_defs: FxHashMap<Mark, DefId>,
1589 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1591 /// List of crate local macros that we need to warn about as being unused.
1592 /// Right now this only includes macro_rules! macros, and macros 2.0.
1593 unused_macros: FxHashSet<DefId>,
1595 /// Maps the `Mark` of an expansion to its containing module or block.
1596 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1598 /// Avoid duplicated errors for "name already defined".
1599 name_already_seen: FxHashMap<Name, Span>,
1601 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1603 /// This table maps struct IDs into struct constructor IDs,
1604 /// it's not used during normal resolution, only for better error reporting.
1605 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1607 /// Only used for better errors on `fn(): fn()`
1608 current_type_ascription: Vec<Span>,
1610 injected_crate: Option<Module<'a>>,
1613 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1615 pub struct ResolverArenas<'a> {
1616 modules: arena::TypedArena<ModuleData<'a>>,
1617 local_modules: RefCell<Vec<Module<'a>>>,
1618 name_bindings: arena::TypedArena<NameBinding<'a>>,
1619 import_directives: arena::TypedArena<ImportDirective<'a>>,
1620 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1621 invocation_data: arena::TypedArena<InvocationData<'a>>,
1622 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1625 impl<'a> ResolverArenas<'a> {
1626 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1627 let module = self.modules.alloc(module);
1628 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1629 self.local_modules.borrow_mut().push(module);
1633 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1634 self.local_modules.borrow()
1636 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1637 self.name_bindings.alloc(name_binding)
1639 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1640 -> &'a ImportDirective {
1641 self.import_directives.alloc(import_directive)
1643 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1644 self.name_resolutions.alloc(Default::default())
1646 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1647 -> &'a InvocationData<'a> {
1648 self.invocation_data.alloc(expansion_data)
1650 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1651 self.legacy_bindings.alloc(binding)
1655 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1656 fn parent(self, id: DefId) -> Option<DefId> {
1658 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1659 _ => self.cstore.def_key(id).parent,
1660 }.map(|index| DefId { index, ..id })
1664 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1665 /// the resolver is no longer needed as all the relevant information is inline.
1666 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1667 fn resolve_hir_path(
1672 self.resolve_hir_path_cb(path, is_value,
1673 |resolver, span, error| resolve_error(resolver, span, error))
1676 fn resolve_str_path(
1679 crate_root: Option<&str>,
1680 components: &[&str],
1683 let segments = iter::once(keywords::PathRoot.ident())
1685 crate_root.into_iter()
1686 .chain(components.iter().cloned())
1687 .map(Ident::from_str)
1688 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1691 let path = ast::Path {
1696 self.resolve_hir_path(&path, is_value)
1699 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1700 self.def_map.get(&id).cloned()
1703 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1704 self.import_map.get(&id).cloned().unwrap_or_default()
1707 fn definitions(&mut self) -> &mut Definitions {
1708 &mut self.definitions
1712 impl<'a> Resolver<'a> {
1713 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1714 /// isn't something that can be returned because it can't be made to live that long,
1715 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1716 /// just that an error occurred.
1717 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1718 -> Result<hir::Path, ()> {
1720 let mut errored = false;
1722 let path = if path_str.starts_with("::") {
1725 segments: iter::once(keywords::PathRoot.ident())
1727 path_str.split("::").skip(1).map(Ident::from_str)
1729 .map(|i| self.new_ast_path_segment(i))
1737 .map(Ident::from_str)
1738 .map(|i| self.new_ast_path_segment(i))
1742 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1743 if errored || path.def == Def::Err {
1750 /// resolve_hir_path, but takes a callback in case there was an error
1751 fn resolve_hir_path_cb<F>(
1757 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1759 let namespace = if is_value { ValueNS } else { TypeNS };
1760 let span = path.span;
1761 let segments = &path.segments;
1762 let path = Segment::from_path(&path);
1763 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1764 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1765 span, CrateLint::No) {
1766 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1767 module.def().unwrap(),
1768 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1769 path_res.base_def(),
1770 PathResult::NonModule(..) => {
1771 let msg = "type-relative paths are not supported in this context";
1772 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1775 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1776 PathResult::Failed(span, msg, _) => {
1777 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1782 let segments: Vec<_> = segments.iter().map(|seg| {
1783 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1784 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1790 segments: segments.into(),
1794 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1795 let mut seg = ast::PathSegment::from_ident(ident);
1796 seg.id = self.session.next_node_id();
1801 impl<'a> Resolver<'a> {
1802 pub fn new(session: &'a Session,
1806 crate_loader: &'a mut CrateLoader<'a>,
1807 arenas: &'a ResolverArenas<'a>)
1809 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1810 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1811 let graph_root = arenas.alloc_module(ModuleData {
1812 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1813 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1815 let mut module_map = FxHashMap::default();
1816 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1818 let mut definitions = Definitions::new();
1819 DefCollector::new(&mut definitions, Mark::root())
1820 .collect_root(crate_name, session.local_crate_disambiguator());
1822 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1823 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1826 if !attr::contains_name(&krate.attrs, "no_core") {
1827 extern_prelude.insert(Ident::from_str("core"), Default::default());
1828 if !attr::contains_name(&krate.attrs, "no_std") {
1829 extern_prelude.insert(Ident::from_str("std"), Default::default());
1830 if session.rust_2018() {
1831 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1836 let mut invocations = FxHashMap::default();
1837 invocations.insert(Mark::root(),
1838 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1840 let mut macro_defs = FxHashMap::default();
1841 macro_defs.insert(Mark::root(), root_def_id);
1850 // The outermost module has def ID 0; this is not reflected in the
1856 has_self: FxHashSet::default(),
1857 field_names: FxHashMap::default(),
1859 determined_imports: Vec::new(),
1860 indeterminate_imports: Vec::new(),
1862 current_module: graph_root,
1864 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1865 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1866 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1868 label_ribs: Vec::new(),
1870 current_trait_ref: None,
1871 current_self_type: None,
1872 current_self_item: None,
1873 last_import_segment: false,
1874 blacklisted_binding: None,
1876 primitive_type_table: PrimitiveTypeTable::new(),
1878 def_map: Default::default(),
1879 import_map: Default::default(),
1880 freevars: Default::default(),
1881 freevars_seen: Default::default(),
1882 export_map: FxHashMap::default(),
1883 trait_map: Default::default(),
1885 block_map: Default::default(),
1886 extern_module_map: FxHashMap::default(),
1887 binding_parent_modules: FxHashMap::default(),
1889 glob_map: Default::default(),
1891 used_imports: FxHashSet::default(),
1892 maybe_unused_trait_imports: Default::default(),
1893 maybe_unused_extern_crates: Vec::new(),
1895 unused_labels: FxHashMap::default(),
1897 privacy_errors: Vec::new(),
1898 ambiguity_errors: Vec::new(),
1899 use_injections: Vec::new(),
1900 macro_expanded_macro_export_errors: BTreeSet::new(),
1903 dummy_binding: arenas.alloc_name_binding(NameBinding {
1904 kind: NameBindingKind::Def(Def::Err, false),
1906 expansion: Mark::root(),
1908 vis: ty::Visibility::Public,
1912 macro_names: FxHashSet::default(),
1913 builtin_macros: FxHashMap::default(),
1914 macro_use_prelude: FxHashMap::default(),
1915 all_macros: FxHashMap::default(),
1916 macro_map: FxHashMap::default(),
1919 local_macro_def_scopes: FxHashMap::default(),
1920 name_already_seen: FxHashMap::default(),
1921 potentially_unused_imports: Vec::new(),
1922 struct_constructors: Default::default(),
1923 unused_macros: FxHashSet::default(),
1924 current_type_ascription: Vec::new(),
1925 injected_crate: None,
1929 pub fn arenas() -> ResolverArenas<'a> {
1933 /// Runs the function on each namespace.
1934 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1940 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1942 match self.macro_defs.get(&ctxt.outer()) {
1943 Some(&def_id) => return def_id,
1944 None => ctxt.remove_mark(),
1949 /// Entry point to crate resolution.
1950 pub fn resolve_crate(&mut self, krate: &Crate) {
1951 ImportResolver { resolver: self }.finalize_imports();
1952 self.current_module = self.graph_root;
1953 self.finalize_current_module_macro_resolutions();
1955 visit::walk_crate(self, krate);
1957 check_unused::check_crate(self, krate);
1958 self.report_errors(krate);
1959 self.crate_loader.postprocess(krate);
1966 normal_ancestor_id: DefId,
1970 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1971 self.arenas.alloc_module(module)
1974 fn record_use(&mut self, ident: Ident, ns: Namespace,
1975 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1976 if let Some((b2, kind)) = used_binding.ambiguity {
1977 self.ambiguity_errors.push(AmbiguityError {
1978 kind, ident, b1: used_binding, b2,
1979 misc1: AmbiguityErrorMisc::None,
1980 misc2: AmbiguityErrorMisc::None,
1983 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1984 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1985 // but not introduce it, as used if they are accessed from lexical scope.
1986 if is_lexical_scope {
1987 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1988 if let Some(crate_item) = entry.extern_crate_item {
1989 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1996 directive.used.set(true);
1997 self.used_imports.insert((directive.id, ns));
1998 self.add_to_glob_map(&directive, ident);
1999 self.record_use(ident, ns, binding, false);
2004 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2005 if directive.is_glob() {
2006 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2010 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2011 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2012 /// `ident` in the first scope that defines it (or None if no scopes define it).
2014 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2015 /// the items are defined in the block. For example,
2018 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2021 /// g(); // This resolves to the local variable `g` since it shadows the item.
2025 /// Invariant: This must only be called during main resolution, not during
2026 /// import resolution.
2027 fn resolve_ident_in_lexical_scope(&mut self,
2030 record_used_id: Option<NodeId>,
2032 -> Option<LexicalScopeBinding<'a>> {
2033 assert!(ns == TypeNS || ns == ValueNS);
2034 if ident.name == keywords::Invalid.name() {
2035 return Some(LexicalScopeBinding::Def(Def::Err));
2037 ident.span = if ident.name == keywords::SelfUpper.name() {
2038 // FIXME(jseyfried) improve `Self` hygiene
2039 ident.span.with_ctxt(SyntaxContext::empty())
2040 } else if ns == TypeNS {
2043 ident.span.modern_and_legacy()
2046 // Walk backwards up the ribs in scope.
2047 let record_used = record_used_id.is_some();
2048 let mut module = self.graph_root;
2049 for i in (0 .. self.ribs[ns].len()).rev() {
2050 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2051 // The ident resolves to a type parameter or local variable.
2052 return Some(LexicalScopeBinding::Def(
2053 self.adjust_local_def(ns, i, def, record_used, path_span)
2057 module = match self.ribs[ns][i].kind {
2058 ModuleRibKind(module) => module,
2059 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2060 // If an invocation of this macro created `ident`, give up on `ident`
2061 // and switch to `ident`'s source from the macro definition.
2062 ident.span.remove_mark();
2068 let item = self.resolve_ident_in_module_unadjusted(
2069 ModuleOrUniformRoot::Module(module),
2075 if let Ok(binding) = item {
2076 // The ident resolves to an item.
2077 return Some(LexicalScopeBinding::Item(binding));
2081 ModuleKind::Block(..) => {}, // We can see through blocks
2086 ident.span = ident.span.modern();
2087 let mut poisoned = None;
2089 let opt_module = if let Some(node_id) = record_used_id {
2090 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2091 node_id, &mut poisoned)
2093 self.hygienic_lexical_parent(module, &mut ident.span)
2095 module = unwrap_or!(opt_module, break);
2096 let orig_current_module = self.current_module;
2097 self.current_module = module; // Lexical resolutions can never be a privacy error.
2098 let result = self.resolve_ident_in_module_unadjusted(
2099 ModuleOrUniformRoot::Module(module),
2105 self.current_module = orig_current_module;
2109 if let Some(node_id) = poisoned {
2110 self.session.buffer_lint_with_diagnostic(
2111 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2112 node_id, ident.span,
2113 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2114 lint::builtin::BuiltinLintDiagnostics::
2115 ProcMacroDeriveResolutionFallback(ident.span),
2118 return Some(LexicalScopeBinding::Item(binding))
2120 Err(Determined) => continue,
2121 Err(Undetermined) =>
2122 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2126 if !module.no_implicit_prelude {
2128 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2129 return Some(LexicalScopeBinding::Item(binding));
2132 if ns == TypeNS && is_known_tool(ident.name) {
2133 let binding = (Def::ToolMod, ty::Visibility::Public,
2134 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2135 return Some(LexicalScopeBinding::Item(binding));
2137 if let Some(prelude) = self.prelude {
2138 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2139 ModuleOrUniformRoot::Module(prelude),
2145 return Some(LexicalScopeBinding::Item(binding));
2153 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2154 -> Option<Module<'a>> {
2155 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2156 return Some(self.macro_def_scope(span.remove_mark()));
2159 if let ModuleKind::Block(..) = module.kind {
2160 return Some(module.parent.unwrap());
2166 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2167 span: &mut Span, node_id: NodeId,
2168 poisoned: &mut Option<NodeId>)
2169 -> Option<Module<'a>> {
2170 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2174 // We need to support the next case under a deprecation warning
2177 // ---- begin: this comes from a proc macro derive
2178 // mod implementation_details {
2179 // // Note that `MyStruct` is not in scope here.
2180 // impl SomeTrait for MyStruct { ... }
2184 // So we have to fall back to the module's parent during lexical resolution in this case.
2185 if let Some(parent) = module.parent {
2186 // Inner module is inside the macro, parent module is outside of the macro.
2187 if module.expansion != parent.expansion &&
2188 module.expansion.is_descendant_of(parent.expansion) {
2189 // The macro is a proc macro derive
2190 if module.expansion.looks_like_proc_macro_derive() {
2191 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2192 *poisoned = Some(node_id);
2193 return module.parent;
2202 fn resolve_ident_in_module(
2204 module: ModuleOrUniformRoot<'a>,
2207 parent_scope: Option<&ParentScope<'a>>,
2210 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2211 self.resolve_ident_in_module_ext(
2212 module, ident, ns, parent_scope, record_used, path_span
2213 ).map_err(|(determinacy, _)| determinacy)
2216 fn resolve_ident_in_module_ext(
2218 module: ModuleOrUniformRoot<'a>,
2221 parent_scope: Option<&ParentScope<'a>>,
2224 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2225 let orig_current_module = self.current_module;
2227 ModuleOrUniformRoot::Module(module) => {
2228 ident.span = ident.span.modern();
2229 if let Some(def) = ident.span.adjust(module.expansion) {
2230 self.current_module = self.macro_def_scope(def);
2233 ModuleOrUniformRoot::ExternPrelude => {
2234 ident.span = ident.span.modern();
2235 ident.span.adjust(Mark::root());
2237 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2238 ModuleOrUniformRoot::CurrentScope => {
2242 let result = self.resolve_ident_in_module_unadjusted_ext(
2243 module, ident, ns, parent_scope, false, record_used, path_span,
2245 self.current_module = orig_current_module;
2249 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2250 let mut ctxt = ident.span.ctxt();
2251 let mark = if ident.name == keywords::DollarCrate.name() {
2252 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2253 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2254 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2255 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2256 // definitions actually produced by `macro` and `macro` definitions produced by
2257 // `macro_rules!`, but at least such configurations are not stable yet.
2258 ctxt = ctxt.modern_and_legacy();
2259 let mut iter = ctxt.marks().into_iter().rev().peekable();
2260 let mut result = None;
2261 // Find the last modern mark from the end if it exists.
2262 while let Some(&(mark, transparency)) = iter.peek() {
2263 if transparency == Transparency::Opaque {
2264 result = Some(mark);
2270 // Then find the last legacy mark from the end if it exists.
2271 for (mark, transparency) in iter {
2272 if transparency == Transparency::SemiTransparent {
2273 result = Some(mark);
2280 ctxt = ctxt.modern();
2281 ctxt.adjust(Mark::root())
2283 let module = match mark {
2284 Some(def) => self.macro_def_scope(def),
2285 None => return self.graph_root,
2287 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2290 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2291 let mut module = self.get_module(module.normal_ancestor_id);
2292 while module.span.ctxt().modern() != *ctxt {
2293 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2294 module = self.get_module(parent.normal_ancestor_id);
2301 // We maintain a list of value ribs and type ribs.
2303 // Simultaneously, we keep track of the current position in the module
2304 // graph in the `current_module` pointer. When we go to resolve a name in
2305 // the value or type namespaces, we first look through all the ribs and
2306 // then query the module graph. When we resolve a name in the module
2307 // namespace, we can skip all the ribs (since nested modules are not
2308 // allowed within blocks in Rust) and jump straight to the current module
2311 // Named implementations are handled separately. When we find a method
2312 // call, we consult the module node to find all of the implementations in
2313 // scope. This information is lazily cached in the module node. We then
2314 // generate a fake "implementation scope" containing all the
2315 // implementations thus found, for compatibility with old resolve pass.
2317 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2318 where F: FnOnce(&mut Resolver) -> T
2320 let id = self.definitions.local_def_id(id);
2321 let module = self.module_map.get(&id).cloned(); // clones a reference
2322 if let Some(module) = module {
2323 // Move down in the graph.
2324 let orig_module = replace(&mut self.current_module, module);
2325 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2326 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2328 self.finalize_current_module_macro_resolutions();
2331 self.current_module = orig_module;
2332 self.ribs[ValueNS].pop();
2333 self.ribs[TypeNS].pop();
2340 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2341 /// is returned by the given predicate function
2343 /// Stops after meeting a closure.
2344 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2345 where P: Fn(&Rib, Ident) -> Option<R>
2347 for rib in self.label_ribs.iter().rev() {
2350 // If an invocation of this macro created `ident`, give up on `ident`
2351 // and switch to `ident`'s source from the macro definition.
2352 MacroDefinition(def) => {
2353 if def == self.macro_def(ident.span.ctxt()) {
2354 ident.span.remove_mark();
2358 // Do not resolve labels across function boundary
2362 let r = pred(rib, ident);
2370 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2371 self.with_current_self_item(item, |this| {
2372 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2373 let item_def_id = this.definitions.local_def_id(item.id);
2374 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2375 visit::walk_item(this, item);
2381 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2382 let segments = &use_tree.prefix.segments;
2383 if !segments.is_empty() {
2384 let ident = segments[0].ident;
2385 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2389 let nss = match use_tree.kind {
2390 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2393 let report_error = |this: &Self, ns| {
2394 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2395 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2399 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2400 Some(LexicalScopeBinding::Def(..)) => {
2401 report_error(self, ns);
2403 Some(LexicalScopeBinding::Item(binding)) => {
2404 let orig_blacklisted_binding =
2405 mem::replace(&mut self.blacklisted_binding, Some(binding));
2406 if let Some(LexicalScopeBinding::Def(..)) =
2407 self.resolve_ident_in_lexical_scope(ident, ns, None,
2408 use_tree.prefix.span) {
2409 report_error(self, ns);
2411 self.blacklisted_binding = orig_blacklisted_binding;
2416 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2417 for (use_tree, _) in use_trees {
2418 self.future_proof_import(use_tree);
2423 fn resolve_item(&mut self, item: &Item) {
2424 let name = item.ident.name;
2425 debug!("(resolving item) resolving {}", name);
2428 ItemKind::Ty(_, ref generics) |
2429 ItemKind::Fn(_, _, ref generics, _) |
2430 ItemKind::Existential(_, ref generics) => {
2431 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2432 |this| visit::walk_item(this, item));
2435 ItemKind::Enum(_, ref generics) |
2436 ItemKind::Struct(_, ref generics) |
2437 ItemKind::Union(_, ref generics) => {
2438 self.resolve_adt(item, generics);
2441 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2442 self.resolve_implementation(generics,
2448 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2449 // Create a new rib for the trait-wide type parameters.
2450 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2451 let local_def_id = this.definitions.local_def_id(item.id);
2452 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2453 this.visit_generics(generics);
2454 walk_list!(this, visit_param_bound, bounds);
2456 for trait_item in trait_items {
2457 let type_parameters = HasTypeParameters(&trait_item.generics,
2458 TraitOrImplItemRibKind);
2459 this.with_type_parameter_rib(type_parameters, |this| {
2460 match trait_item.node {
2461 TraitItemKind::Const(ref ty, ref default) => {
2464 // Only impose the restrictions of
2465 // ConstRibKind for an actual constant
2466 // expression in a provided default.
2467 if let Some(ref expr) = *default{
2468 this.with_constant_rib(|this| {
2469 this.visit_expr(expr);
2473 TraitItemKind::Method(_, _) => {
2474 visit::walk_trait_item(this, trait_item)
2476 TraitItemKind::Type(..) => {
2477 visit::walk_trait_item(this, trait_item)
2479 TraitItemKind::Macro(_) => {
2480 panic!("unexpanded macro in resolve!")
2489 ItemKind::TraitAlias(ref generics, ref bounds) => {
2490 // Create a new rib for the trait-wide type parameters.
2491 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2492 let local_def_id = this.definitions.local_def_id(item.id);
2493 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2494 this.visit_generics(generics);
2495 walk_list!(this, visit_param_bound, bounds);
2500 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2501 self.with_scope(item.id, |this| {
2502 visit::walk_item(this, item);
2506 ItemKind::Static(ref ty, _, ref expr) |
2507 ItemKind::Const(ref ty, ref expr) => {
2508 self.with_item_rib(|this| {
2510 this.with_constant_rib(|this| {
2511 this.visit_expr(expr);
2516 ItemKind::Use(ref use_tree) => {
2517 self.future_proof_import(use_tree);
2520 ItemKind::ExternCrate(..) |
2521 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2522 // do nothing, these are just around to be encoded
2525 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2529 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2530 where F: FnOnce(&mut Resolver)
2532 match type_parameters {
2533 HasTypeParameters(generics, rib_kind) => {
2534 let mut function_type_rib = Rib::new(rib_kind);
2535 let mut seen_bindings = FxHashMap::default();
2536 for param in &generics.params {
2538 GenericParamKind::Lifetime { .. } => {}
2539 GenericParamKind::Type { .. } => {
2540 let ident = param.ident.modern();
2541 debug!("with_type_parameter_rib: {}", param.id);
2543 if seen_bindings.contains_key(&ident) {
2544 let span = seen_bindings.get(&ident).unwrap();
2545 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2549 resolve_error(self, param.ident.span, err);
2551 seen_bindings.entry(ident).or_insert(param.ident.span);
2553 // Plain insert (no renaming).
2554 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2555 function_type_rib.bindings.insert(ident, def);
2556 self.record_def(param.id, PathResolution::new(def));
2560 self.ribs[TypeNS].push(function_type_rib);
2563 NoTypeParameters => {
2570 if let HasTypeParameters(..) = type_parameters {
2571 self.ribs[TypeNS].pop();
2575 fn with_label_rib<F>(&mut self, f: F)
2576 where F: FnOnce(&mut Resolver)
2578 self.label_ribs.push(Rib::new(NormalRibKind));
2580 self.label_ribs.pop();
2583 fn with_item_rib<F>(&mut self, f: F)
2584 where F: FnOnce(&mut Resolver)
2586 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2587 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2589 self.ribs[TypeNS].pop();
2590 self.ribs[ValueNS].pop();
2593 fn with_constant_rib<F>(&mut self, f: F)
2594 where F: FnOnce(&mut Resolver)
2596 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2597 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2599 self.label_ribs.pop();
2600 self.ribs[ValueNS].pop();
2603 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2604 where F: FnOnce(&mut Resolver) -> T
2606 // Handle nested impls (inside fn bodies)
2607 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2608 let result = f(self);
2609 self.current_self_type = previous_value;
2613 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2614 where F: FnOnce(&mut Resolver) -> T
2616 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2617 let result = f(self);
2618 self.current_self_item = previous_value;
2622 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2623 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2624 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2626 let mut new_val = None;
2627 let mut new_id = None;
2628 if let Some(trait_ref) = opt_trait_ref {
2629 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2630 let def = self.smart_resolve_path_fragment(
2634 trait_ref.path.span,
2635 PathSource::Trait(AliasPossibility::No),
2636 CrateLint::SimplePath(trait_ref.ref_id),
2638 if def != Def::Err {
2639 new_id = Some(def.def_id());
2640 let span = trait_ref.path.span;
2641 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2642 self.resolve_path_without_parent_scope(
2647 CrateLint::SimplePath(trait_ref.ref_id),
2650 new_val = Some((module, trait_ref.clone()));
2654 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2655 let result = f(self, new_id);
2656 self.current_trait_ref = original_trait_ref;
2660 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2661 where F: FnOnce(&mut Resolver)
2663 let mut self_type_rib = Rib::new(NormalRibKind);
2665 // plain insert (no renaming, types are not currently hygienic....)
2666 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2667 self.ribs[TypeNS].push(self_type_rib);
2669 self.ribs[TypeNS].pop();
2672 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2673 where F: FnOnce(&mut Resolver)
2675 let self_def = Def::SelfCtor(impl_id);
2676 let mut self_type_rib = Rib::new(NormalRibKind);
2677 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2678 self.ribs[ValueNS].push(self_type_rib);
2680 self.ribs[ValueNS].pop();
2683 fn resolve_implementation(&mut self,
2684 generics: &Generics,
2685 opt_trait_reference: &Option<TraitRef>,
2688 impl_items: &[ImplItem]) {
2689 // If applicable, create a rib for the type parameters.
2690 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2691 // Dummy self type for better errors if `Self` is used in the trait path.
2692 this.with_self_rib(Def::SelfTy(None, None), |this| {
2693 // Resolve the trait reference, if necessary.
2694 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2695 let item_def_id = this.definitions.local_def_id(item_id);
2696 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2697 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2698 // Resolve type arguments in the trait path.
2699 visit::walk_trait_ref(this, trait_ref);
2701 // Resolve the self type.
2702 this.visit_ty(self_type);
2703 // Resolve the type parameters.
2704 this.visit_generics(generics);
2705 // Resolve the items within the impl.
2706 this.with_current_self_type(self_type, |this| {
2707 this.with_self_struct_ctor_rib(item_def_id, |this| {
2708 for impl_item in impl_items {
2709 this.resolve_visibility(&impl_item.vis);
2711 // We also need a new scope for the impl item type parameters.
2712 let type_parameters = HasTypeParameters(&impl_item.generics,
2713 TraitOrImplItemRibKind);
2714 this.with_type_parameter_rib(type_parameters, |this| {
2715 use self::ResolutionError::*;
2716 match impl_item.node {
2717 ImplItemKind::Const(..) => {
2718 // If this is a trait impl, ensure the const
2720 this.check_trait_item(impl_item.ident,
2723 |n, s| ConstNotMemberOfTrait(n, s));
2724 this.with_constant_rib(|this|
2725 visit::walk_impl_item(this, impl_item)
2728 ImplItemKind::Method(..) => {
2729 // If this is a trait impl, ensure the method
2731 this.check_trait_item(impl_item.ident,
2734 |n, s| MethodNotMemberOfTrait(n, s));
2736 visit::walk_impl_item(this, impl_item);
2738 ImplItemKind::Type(ref ty) => {
2739 // If this is a trait impl, ensure the type
2741 this.check_trait_item(impl_item.ident,
2744 |n, s| TypeNotMemberOfTrait(n, s));
2748 ImplItemKind::Existential(ref bounds) => {
2749 // If this is a trait impl, ensure the type
2751 this.check_trait_item(impl_item.ident,
2754 |n, s| TypeNotMemberOfTrait(n, s));
2756 for bound in bounds {
2757 this.visit_param_bound(bound);
2760 ImplItemKind::Macro(_) =>
2761 panic!("unexpanded macro in resolve!"),
2773 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2774 where F: FnOnce(Name, &str) -> ResolutionError
2776 // If there is a TraitRef in scope for an impl, then the method must be in the
2778 if let Some((module, _)) = self.current_trait_ref {
2779 if self.resolve_ident_in_module(
2780 ModuleOrUniformRoot::Module(module),
2787 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2788 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2793 fn resolve_local(&mut self, local: &Local) {
2794 // Resolve the type.
2795 walk_list!(self, visit_ty, &local.ty);
2797 // Resolve the initializer.
2798 walk_list!(self, visit_expr, &local.init);
2800 // Resolve the pattern.
2801 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2804 // build a map from pattern identifiers to binding-info's.
2805 // this is done hygienically. This could arise for a macro
2806 // that expands into an or-pattern where one 'x' was from the
2807 // user and one 'x' came from the macro.
2808 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2809 let mut binding_map = FxHashMap::default();
2811 pat.walk(&mut |pat| {
2812 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2813 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2814 Some(Def::Local(..)) => true,
2817 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2818 binding_map.insert(ident, binding_info);
2827 // check that all of the arms in an or-pattern have exactly the
2828 // same set of bindings, with the same binding modes for each.
2829 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2830 if pats.is_empty() {
2834 let mut missing_vars = FxHashMap::default();
2835 let mut inconsistent_vars = FxHashMap::default();
2836 for (i, p) in pats.iter().enumerate() {
2837 let map_i = self.binding_mode_map(&p);
2839 for (j, q) in pats.iter().enumerate() {
2844 let map_j = self.binding_mode_map(&q);
2845 for (&key, &binding_i) in &map_i {
2846 if map_j.is_empty() { // Account for missing bindings when
2847 let binding_error = missing_vars // map_j has none.
2849 .or_insert(BindingError {
2851 origin: BTreeSet::new(),
2852 target: BTreeSet::new(),
2854 binding_error.origin.insert(binding_i.span);
2855 binding_error.target.insert(q.span);
2857 for (&key_j, &binding_j) in &map_j {
2858 match map_i.get(&key_j) {
2859 None => { // missing binding
2860 let binding_error = missing_vars
2862 .or_insert(BindingError {
2864 origin: BTreeSet::new(),
2865 target: BTreeSet::new(),
2867 binding_error.origin.insert(binding_j.span);
2868 binding_error.target.insert(p.span);
2870 Some(binding_i) => { // check consistent binding
2871 if binding_i.binding_mode != binding_j.binding_mode {
2874 .or_insert((binding_j.span, binding_i.span));
2882 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2883 missing_vars.sort();
2884 for (_, v) in missing_vars {
2886 *v.origin.iter().next().unwrap(),
2887 ResolutionError::VariableNotBoundInPattern(v));
2889 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2890 inconsistent_vars.sort();
2891 for (name, v) in inconsistent_vars {
2892 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2896 fn resolve_arm(&mut self, arm: &Arm) {
2897 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2899 let mut bindings_list = FxHashMap::default();
2900 for pattern in &arm.pats {
2901 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2904 // This has to happen *after* we determine which pat_idents are variants.
2905 self.check_consistent_bindings(&arm.pats);
2907 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2908 self.visit_expr(expr)
2910 self.visit_expr(&arm.body);
2912 self.ribs[ValueNS].pop();
2915 fn resolve_block(&mut self, block: &Block) {
2916 debug!("(resolving block) entering block");
2917 // Move down in the graph, if there's an anonymous module rooted here.
2918 let orig_module = self.current_module;
2919 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2921 let mut num_macro_definition_ribs = 0;
2922 if let Some(anonymous_module) = anonymous_module {
2923 debug!("(resolving block) found anonymous module, moving down");
2924 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2925 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2926 self.current_module = anonymous_module;
2927 self.finalize_current_module_macro_resolutions();
2929 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2932 // Descend into the block.
2933 for stmt in &block.stmts {
2934 if let ast::StmtKind::Item(ref item) = stmt.node {
2935 if let ast::ItemKind::MacroDef(..) = item.node {
2936 num_macro_definition_ribs += 1;
2937 let def = self.definitions.local_def_id(item.id);
2938 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2939 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2943 self.visit_stmt(stmt);
2947 self.current_module = orig_module;
2948 for _ in 0 .. num_macro_definition_ribs {
2949 self.ribs[ValueNS].pop();
2950 self.label_ribs.pop();
2952 self.ribs[ValueNS].pop();
2953 if anonymous_module.is_some() {
2954 self.ribs[TypeNS].pop();
2956 debug!("(resolving block) leaving block");
2959 fn fresh_binding(&mut self,
2962 outer_pat_id: NodeId,
2963 pat_src: PatternSource,
2964 bindings: &mut FxHashMap<Ident, NodeId>)
2966 // Add the binding to the local ribs, if it
2967 // doesn't already exist in the bindings map. (We
2968 // must not add it if it's in the bindings map
2969 // because that breaks the assumptions later
2970 // passes make about or-patterns.)
2971 let ident = ident.modern_and_legacy();
2972 let mut def = Def::Local(pat_id);
2973 match bindings.get(&ident).cloned() {
2974 Some(id) if id == outer_pat_id => {
2975 // `Variant(a, a)`, error
2979 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2983 Some(..) if pat_src == PatternSource::FnParam => {
2984 // `fn f(a: u8, a: u8)`, error
2988 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2992 Some(..) if pat_src == PatternSource::Match ||
2993 pat_src == PatternSource::IfLet ||
2994 pat_src == PatternSource::WhileLet => {
2995 // `Variant1(a) | Variant2(a)`, ok
2996 // Reuse definition from the first `a`.
2997 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3000 span_bug!(ident.span, "two bindings with the same name from \
3001 unexpected pattern source {:?}", pat_src);
3004 // A completely fresh binding, add to the lists if it's valid.
3005 if ident.name != keywords::Invalid.name() {
3006 bindings.insert(ident, outer_pat_id);
3007 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3012 PathResolution::new(def)
3015 fn resolve_pattern(&mut self,
3017 pat_src: PatternSource,
3018 // Maps idents to the node ID for the
3019 // outermost pattern that binds them.
3020 bindings: &mut FxHashMap<Ident, NodeId>) {
3021 // Visit all direct subpatterns of this pattern.
3022 let outer_pat_id = pat.id;
3023 pat.walk(&mut |pat| {
3024 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3026 PatKind::Ident(bmode, ident, ref opt_pat) => {
3027 // First try to resolve the identifier as some existing
3028 // entity, then fall back to a fresh binding.
3029 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3031 .and_then(LexicalScopeBinding::item);
3032 let resolution = binding.map(NameBinding::def).and_then(|def| {
3033 let is_syntactic_ambiguity = opt_pat.is_none() &&
3034 bmode == BindingMode::ByValue(Mutability::Immutable);
3036 Def::StructCtor(_, CtorKind::Const) |
3037 Def::VariantCtor(_, CtorKind::Const) |
3038 Def::Const(..) if is_syntactic_ambiguity => {
3039 // Disambiguate in favor of a unit struct/variant
3040 // or constant pattern.
3041 self.record_use(ident, ValueNS, binding.unwrap(), false);
3042 Some(PathResolution::new(def))
3044 Def::StructCtor(..) | Def::VariantCtor(..) |
3045 Def::Const(..) | Def::Static(..) => {
3046 // This is unambiguously a fresh binding, either syntactically
3047 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3048 // to something unusable as a pattern (e.g., constructor function),
3049 // but we still conservatively report an error, see
3050 // issues/33118#issuecomment-233962221 for one reason why.
3054 ResolutionError::BindingShadowsSomethingUnacceptable(
3055 pat_src.descr(), ident.name, binding.unwrap())
3059 Def::Fn(..) | Def::Err => {
3060 // These entities are explicitly allowed
3061 // to be shadowed by fresh bindings.
3065 span_bug!(ident.span, "unexpected definition for an \
3066 identifier in pattern: {:?}", def);
3069 }).unwrap_or_else(|| {
3070 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3073 self.record_def(pat.id, resolution);
3076 PatKind::TupleStruct(ref path, ..) => {
3077 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3080 PatKind::Path(ref qself, ref path) => {
3081 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3084 PatKind::Struct(ref path, ..) => {
3085 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3093 visit::walk_pat(self, pat);
3096 // High-level and context dependent path resolution routine.
3097 // Resolves the path and records the resolution into definition map.
3098 // If resolution fails tries several techniques to find likely
3099 // resolution candidates, suggest imports or other help, and report
3100 // errors in user friendly way.
3101 fn smart_resolve_path(&mut self,
3103 qself: Option<&QSelf>,
3107 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3110 /// A variant of `smart_resolve_path` where you also specify extra
3111 /// information about where the path came from; this extra info is
3112 /// sometimes needed for the lint that recommends rewriting
3113 /// absolute paths to `crate`, so that it knows how to frame the
3114 /// suggestion. If you are just resolving a path like `foo::bar`
3115 /// that appears...somewhere, though, then you just want
3116 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3117 /// already provides.
3118 fn smart_resolve_path_with_crate_lint(
3121 qself: Option<&QSelf>,
3124 crate_lint: CrateLint
3125 ) -> PathResolution {
3126 self.smart_resolve_path_fragment(
3129 &Segment::from_path(path),
3136 fn smart_resolve_path_fragment(&mut self,
3138 qself: Option<&QSelf>,
3142 crate_lint: CrateLint)
3144 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3145 let ns = source.namespace();
3146 let is_expected = &|def| source.is_expected(def);
3147 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3149 // Base error is amended with one short label and possibly some longer helps/notes.
3150 let report_errors = |this: &mut Self, def: Option<Def>| {
3151 // Make the base error.
3152 let expected = source.descr_expected();
3153 let path_str = Segment::names_to_string(path);
3154 let item_str = path.last().unwrap().ident;
3155 let code = source.error_code(def.is_some());
3156 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3157 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3158 format!("not a {}", expected),
3161 let item_span = path.last().unwrap().ident.span;
3162 let (mod_prefix, mod_str) = if path.len() == 1 {
3163 (String::new(), "this scope".to_string())
3164 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3165 (String::new(), "the crate root".to_string())
3167 let mod_path = &path[..path.len() - 1];
3168 let mod_prefix = match this.resolve_path_without_parent_scope(
3169 mod_path, Some(TypeNS), false, span, CrateLint::No
3171 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3174 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3175 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3177 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3178 format!("not found in {}", mod_str),
3182 let code = DiagnosticId::Error(code.into());
3183 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3185 // Emit help message for fake-self from other languages like `this`(javascript)
3186 if ["this", "my"].contains(&&*item_str.as_str())
3187 && this.self_value_is_available(path[0].ident.span, span) {
3188 err.span_suggestion(
3192 Applicability::MaybeIncorrect,
3196 // Emit special messages for unresolved `Self` and `self`.
3197 if is_self_type(path, ns) {
3198 __diagnostic_used!(E0411);
3199 err.code(DiagnosticId::Error("E0411".into()));
3200 err.span_label(span, format!("`Self` is only available in impls, traits, \
3201 and type definitions"));
3202 return (err, Vec::new());
3204 if is_self_value(path, ns) {
3205 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3207 __diagnostic_used!(E0424);
3208 err.code(DiagnosticId::Error("E0424".into()));
3209 err.span_label(span, match source {
3210 PathSource::Pat => {
3211 format!("`self` value is a keyword \
3212 and may not be bound to \
3213 variables or shadowed")
3216 format!("`self` value is a keyword \
3217 only available in methods \
3218 with `self` parameter")
3221 return (err, Vec::new());
3224 // Try to lookup the name in more relaxed fashion for better error reporting.
3225 let ident = path.last().unwrap().ident;
3226 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3227 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3228 let enum_candidates =
3229 this.lookup_import_candidates(ident, ns, is_enum_variant);
3230 let mut enum_candidates = enum_candidates.iter()
3232 import_candidate_to_enum_paths(&suggestion)
3233 }).collect::<Vec<_>>();
3234 enum_candidates.sort();
3236 if !enum_candidates.is_empty() {
3237 // contextualize for E0412 "cannot find type", but don't belabor the point
3238 // (that it's a variant) for E0573 "expected type, found variant"
3239 let preamble = if def.is_none() {
3240 let others = match enum_candidates.len() {
3242 2 => " and 1 other".to_owned(),
3243 n => format!(" and {} others", n)
3245 format!("there is an enum variant `{}`{}; ",
3246 enum_candidates[0].0, others)
3250 let msg = format!("{}try using the variant's enum", preamble);
3252 err.span_suggestions(
3255 enum_candidates.into_iter()
3256 .map(|(_variant_path, enum_ty_path)| enum_ty_path)
3257 // variants reëxported in prelude doesn't mean `prelude::v1` is the
3258 // type name! FIXME: is there a more principled way to do this that
3259 // would work for other reëxports?
3260 .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
3261 // also say `Option` rather than `std::prelude::v1::Option`
3262 .map(|enum_ty_path| {
3263 // FIXME #56861: DRYer prelude filtering
3264 enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
3266 Applicability::MachineApplicable,
3270 if path.len() == 1 && this.self_type_is_available(span) {
3271 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3272 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3274 AssocSuggestion::Field => {
3275 err.span_suggestion(
3278 format!("self.{}", path_str),
3279 Applicability::MachineApplicable,
3281 if !self_is_available {
3282 err.span_label(span, format!("`self` value is a keyword \
3284 methods with `self` parameter"));
3287 AssocSuggestion::MethodWithSelf if self_is_available => {
3288 err.span_suggestion(
3291 format!("self.{}", path_str),
3292 Applicability::MachineApplicable,
3295 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3296 err.span_suggestion(
3299 format!("Self::{}", path_str),
3300 Applicability::MachineApplicable,
3304 return (err, candidates);
3308 let mut levenshtein_worked = false;
3310 // Try Levenshtein algorithm.
3311 let suggestion = this.lookup_typo_candidate(path, ns, is_expected, span);
3312 if let Some(suggestion) = suggestion {
3314 "{} {} with a similar name exists",
3315 suggestion.article, suggestion.kind
3317 err.span_suggestion(
3320 suggestion.candidate.to_string(),
3321 Applicability::MaybeIncorrect,
3324 levenshtein_worked = true;
3327 // Try context dependent help if relaxed lookup didn't work.
3328 if let Some(def) = def {
3329 match (def, source) {
3330 (Def::Macro(..), _) => {
3331 err.span_suggestion(
3333 "use `!` to invoke the macro",
3334 format!("{}!", path_str),
3335 Applicability::MaybeIncorrect,
3337 return (err, candidates);
3339 (Def::TyAlias(..), PathSource::Trait(_)) => {
3340 err.span_label(span, "type aliases cannot be used as traits");
3341 if nightly_options::is_nightly_build() {
3342 err.note("did you mean to use a trait alias?");
3344 return (err, candidates);
3346 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3347 ExprKind::Field(_, ident) => {
3348 err.span_suggestion(
3350 "use the path separator to refer to an item",
3351 format!("{}::{}", path_str, ident),
3352 Applicability::MaybeIncorrect,
3354 return (err, candidates);
3356 ExprKind::MethodCall(ref segment, ..) => {
3357 let span = parent.span.with_hi(segment.ident.span.hi());
3358 err.span_suggestion(
3360 "use the path separator to refer to an item",
3361 format!("{}::{}", path_str, segment.ident),
3362 Applicability::MaybeIncorrect,
3364 return (err, candidates);
3368 (Def::Enum(..), PathSource::TupleStruct)
3369 | (Def::Enum(..), PathSource::Expr(..)) => {
3370 if let Some(variants) = this.collect_enum_variants(def) {
3371 err.note(&format!("did you mean to use one \
3372 of the following variants?\n{}",
3374 .map(|suggestion| path_names_to_string(suggestion))
3375 .map(|suggestion| format!("- `{}`", suggestion))
3376 .collect::<Vec<_>>()
3380 err.note("did you mean to use one of the enum's variants?");
3382 return (err, candidates);
3384 (Def::Struct(def_id), _) if ns == ValueNS => {
3385 if let Some((ctor_def, ctor_vis))
3386 = this.struct_constructors.get(&def_id).cloned() {
3387 let accessible_ctor = this.is_accessible(ctor_vis);
3388 if is_expected(ctor_def) && !accessible_ctor {
3389 err.span_label(span, format!("constructor is not visible \
3390 here due to private fields"));
3393 // HACK(estebank): find a better way to figure out that this was a
3394 // parser issue where a struct literal is being used on an expression
3395 // where a brace being opened means a block is being started. Look
3396 // ahead for the next text to see if `span` is followed by a `{`.
3397 let sm = this.session.source_map();
3400 sp = sm.next_point(sp);
3401 match sm.span_to_snippet(sp) {
3402 Ok(ref snippet) => {
3403 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3410 let followed_by_brace = match sm.span_to_snippet(sp) {
3411 Ok(ref snippet) if snippet == "{" => true,
3414 // In case this could be a struct literal that needs to be surrounded
3415 // by parenthesis, find the appropriate span.
3417 let mut closing_brace = None;
3419 sp = sm.next_point(sp);
3420 match sm.span_to_snippet(sp) {
3421 Ok(ref snippet) => {
3423 let sp = span.to(sp);
3424 if let Ok(snippet) = sm.span_to_snippet(sp) {
3425 closing_brace = Some((sp, snippet));
3433 if i > 100 { // The bigger the span the more likely we're
3434 break; // incorrect. Bound it to 100 chars long.
3438 PathSource::Expr(Some(parent)) => {
3440 ExprKind::MethodCall(ref path_assignment, _) => {
3441 err.span_suggestion(
3442 sm.start_point(parent.span)
3443 .to(path_assignment.ident.span),
3444 "use `::` to access an associated function",
3447 path_assignment.ident),
3448 Applicability::MaybeIncorrect
3450 return (err, candidates);
3455 format!("did you mean `{} {{ /* fields */ }}`?",
3458 return (err, candidates);
3462 PathSource::Expr(None) if followed_by_brace == true => {
3463 if let Some((sp, snippet)) = closing_brace {
3464 err.span_suggestion(
3466 "surround the struct literal with parenthesis",
3467 format!("({})", snippet),
3468 Applicability::MaybeIncorrect,
3473 format!("did you mean `({} {{ /* fields */ }})`?",
3477 return (err, candidates);
3482 format!("did you mean `{} {{ /* fields */ }}`?",
3485 return (err, candidates);
3489 return (err, candidates);
3491 (Def::Union(..), _) |
3492 (Def::Variant(..), _) |
3493 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3494 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3496 return (err, candidates);
3498 (Def::SelfTy(..), _) if ns == ValueNS => {
3499 err.span_label(span, fallback_label);
3500 err.note("can't use `Self` as a constructor, you must use the \
3501 implemented struct");
3502 return (err, candidates);
3504 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3505 err.note("can't use a type alias as a constructor");
3506 return (err, candidates);
3513 if !levenshtein_worked {
3514 err.span_label(base_span, fallback_label);
3515 this.type_ascription_suggestion(&mut err, base_span);
3519 let report_errors = |this: &mut Self, def: Option<Def>| {
3520 let (err, candidates) = report_errors(this, def);
3521 let def_id = this.current_module.normal_ancestor_id;
3522 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3523 let better = def.is_some();
3524 this.use_injections.push(UseError { err, candidates, node_id, better });
3525 err_path_resolution()
3528 let resolution = match self.resolve_qpath_anywhere(
3534 source.defer_to_typeck(),
3535 source.global_by_default(),
3538 Some(resolution) if resolution.unresolved_segments() == 0 => {
3539 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3542 // Add a temporary hack to smooth the transition to new struct ctor
3543 // visibility rules. See #38932 for more details.
3545 if let Def::Struct(def_id) = resolution.base_def() {
3546 if let Some((ctor_def, ctor_vis))
3547 = self.struct_constructors.get(&def_id).cloned() {
3548 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3549 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3550 self.session.buffer_lint(lint, id, span,
3551 "private struct constructors are not usable through \
3552 re-exports in outer modules",
3554 res = Some(PathResolution::new(ctor_def));
3559 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3562 Some(resolution) if source.defer_to_typeck() => {
3563 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3564 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3565 // it needs to be added to the trait map.
3567 let item_name = path.last().unwrap().ident;
3568 let traits = self.get_traits_containing_item(item_name, ns);
3569 self.trait_map.insert(id, traits);
3573 _ => report_errors(self, None)
3576 if let PathSource::TraitItem(..) = source {} else {
3577 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3578 self.record_def(id, resolution);
3583 fn type_ascription_suggestion(&self,
3584 err: &mut DiagnosticBuilder,
3586 debug!("type_ascription_suggetion {:?}", base_span);
3587 let cm = self.session.source_map();
3588 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3589 if let Some(sp) = self.current_type_ascription.last() {
3591 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3592 sp = cm.next_point(sp);
3593 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3594 debug!("snippet {:?}", snippet);
3595 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3596 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3597 debug!("{:?} {:?}", line_sp, line_base_sp);
3599 err.span_label(base_span,
3600 "expecting a type here because of type ascription");
3601 if line_sp != line_base_sp {
3602 err.span_suggestion_short(
3604 "did you mean to use `;` here instead?",
3606 Applicability::MaybeIncorrect,
3610 } else if !snippet.trim().is_empty() {
3611 debug!("tried to find type ascription `:` token, couldn't find it");
3621 fn self_type_is_available(&mut self, span: Span) -> bool {
3622 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3623 TypeNS, None, span);
3624 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3627 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3628 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3629 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3630 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3633 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3634 fn resolve_qpath_anywhere(&mut self,
3636 qself: Option<&QSelf>,
3638 primary_ns: Namespace,
3640 defer_to_typeck: bool,
3641 global_by_default: bool,
3642 crate_lint: CrateLint)
3643 -> Option<PathResolution> {
3644 let mut fin_res = None;
3645 // FIXME: can't resolve paths in macro namespace yet, macros are
3646 // processed by the little special hack below.
3647 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3648 if i == 0 || ns != primary_ns {
3649 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3650 // If defer_to_typeck, then resolution > no resolution,
3651 // otherwise full resolution > partial resolution > no resolution.
3652 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3654 res => if fin_res.is_none() { fin_res = res },
3658 if primary_ns != MacroNS &&
3659 (self.macro_names.contains(&path[0].ident.modern()) ||
3660 self.builtin_macros.get(&path[0].ident.name).cloned()
3661 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3662 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3663 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3664 // Return some dummy definition, it's enough for error reporting.
3666 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3672 /// Handles paths that may refer to associated items.
3673 fn resolve_qpath(&mut self,
3675 qself: Option<&QSelf>,
3679 global_by_default: bool,
3680 crate_lint: CrateLint)
3681 -> Option<PathResolution> {
3683 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3684 ns={:?}, span={:?}, global_by_default={:?})",
3693 if let Some(qself) = qself {
3694 if qself.position == 0 {
3695 // This is a case like `<T>::B`, where there is no
3696 // trait to resolve. In that case, we leave the `B`
3697 // segment to be resolved by type-check.
3698 return Some(PathResolution::with_unresolved_segments(
3699 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3703 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3705 // Currently, `path` names the full item (`A::B::C`, in
3706 // our example). so we extract the prefix of that that is
3707 // the trait (the slice upto and including
3708 // `qself.position`). And then we recursively resolve that,
3709 // but with `qself` set to `None`.
3711 // However, setting `qself` to none (but not changing the
3712 // span) loses the information about where this path
3713 // *actually* appears, so for the purposes of the crate
3714 // lint we pass along information that this is the trait
3715 // name from a fully qualified path, and this also
3716 // contains the full span (the `CrateLint::QPathTrait`).
3717 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3718 let res = self.smart_resolve_path_fragment(
3721 &path[..=qself.position],
3723 PathSource::TraitItem(ns),
3724 CrateLint::QPathTrait {
3726 qpath_span: qself.path_span,
3730 // The remaining segments (the `C` in our example) will
3731 // have to be resolved by type-check, since that requires doing
3732 // trait resolution.
3733 return Some(PathResolution::with_unresolved_segments(
3734 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3738 let result = match self.resolve_path_without_parent_scope(
3745 PathResult::NonModule(path_res) => path_res,
3746 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3747 PathResolution::new(module.def().unwrap())
3749 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3750 // don't report an error right away, but try to fallback to a primitive type.
3751 // So, we are still able to successfully resolve something like
3753 // use std::u8; // bring module u8 in scope
3754 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3755 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3756 // // not to non-existent std::u8::max_value
3759 // Such behavior is required for backward compatibility.
3760 // The same fallback is used when `a` resolves to nothing.
3761 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3762 PathResult::Failed(..)
3763 if (ns == TypeNS || path.len() > 1) &&
3764 self.primitive_type_table.primitive_types
3765 .contains_key(&path[0].ident.name) => {
3766 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3767 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3769 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3770 PathResolution::new(module.def().unwrap()),
3771 PathResult::Failed(span, msg, false) => {
3772 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3773 err_path_resolution()
3775 PathResult::Module(..) | PathResult::Failed(..) => return None,
3776 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3779 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3780 path[0].ident.name != keywords::PathRoot.name() &&
3781 path[0].ident.name != keywords::DollarCrate.name() {
3782 let unqualified_result = {
3783 match self.resolve_path_without_parent_scope(
3784 &[*path.last().unwrap()],
3790 PathResult::NonModule(path_res) => path_res.base_def(),
3791 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3792 module.def().unwrap(),
3793 _ => return Some(result),
3796 if result.base_def() == unqualified_result {
3797 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3798 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3805 fn resolve_path_without_parent_scope(
3808 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3811 crate_lint: CrateLint,
3812 ) -> PathResult<'a> {
3813 // Macro and import paths must have full parent scope available during resolution,
3814 // other paths will do okay with parent module alone.
3815 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3816 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3817 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3823 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3824 parent_scope: &ParentScope<'a>,
3827 crate_lint: CrateLint,
3828 ) -> PathResult<'a> {
3829 let mut module = None;
3830 let mut allow_super = true;
3831 let mut second_binding = None;
3832 self.current_module = parent_scope.module;
3835 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3836 path_span={:?}, crate_lint={:?})",
3844 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3845 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3846 let record_segment_def = |this: &mut Self, def| {
3848 if let Some(id) = id {
3849 if !this.def_map.contains_key(&id) {
3850 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3851 this.record_def(id, PathResolution::new(def));
3857 let is_last = i == path.len() - 1;
3858 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3859 let name = ident.name;
3861 allow_super &= ns == TypeNS &&
3862 (name == keywords::SelfLower.name() ||
3863 name == keywords::Super.name());
3866 if allow_super && name == keywords::Super.name() {
3867 let mut ctxt = ident.span.ctxt().modern();
3868 let self_module = match i {
3869 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3871 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3875 if let Some(self_module) = self_module {
3876 if let Some(parent) = self_module.parent {
3877 module = Some(ModuleOrUniformRoot::Module(
3878 self.resolve_self(&mut ctxt, parent)));
3882 let msg = "there are too many initial `super`s.".to_string();
3883 return PathResult::Failed(ident.span, msg, false);
3886 if name == keywords::SelfLower.name() {
3887 let mut ctxt = ident.span.ctxt().modern();
3888 module = Some(ModuleOrUniformRoot::Module(
3889 self.resolve_self(&mut ctxt, self.current_module)));
3892 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3893 module = Some(ModuleOrUniformRoot::ExternPrelude);
3896 if name == keywords::PathRoot.name() &&
3897 ident.span.rust_2015() && self.session.rust_2018() {
3898 // `::a::b` from 2015 macro on 2018 global edition
3899 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3902 if name == keywords::PathRoot.name() ||
3903 name == keywords::Crate.name() ||
3904 name == keywords::DollarCrate.name() {
3905 // `::a::b`, `crate::a::b` or `$crate::a::b`
3906 module = Some(ModuleOrUniformRoot::Module(
3907 self.resolve_crate_root(ident)));
3913 // Report special messages for path segment keywords in wrong positions.
3914 if ident.is_path_segment_keyword() && i != 0 {
3915 let name_str = if name == keywords::PathRoot.name() {
3916 "crate root".to_string()
3918 format!("`{}`", name)
3920 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3921 format!("global paths cannot start with {}", name_str)
3923 format!("{} in paths can only be used in start position", name_str)
3925 return PathResult::Failed(ident.span, msg, false);
3928 let binding = if let Some(module) = module {
3929 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3930 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3931 assert!(ns == TypeNS);
3932 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3933 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3934 record_used, path_span)
3936 let record_used_id =
3937 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3938 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3939 // we found a locally-imported or available item/module
3940 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3941 // we found a local variable or type param
3942 Some(LexicalScopeBinding::Def(def))
3943 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3944 record_segment_def(self, def);
3945 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3949 _ => Err(Determinacy::determined(record_used)),
3956 second_binding = Some(binding);
3958 let def = binding.def();
3959 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3960 if let Some(next_module) = binding.module() {
3961 module = Some(ModuleOrUniformRoot::Module(next_module));
3962 record_segment_def(self, def);
3963 } else if def == Def::ToolMod && i + 1 != path.len() {
3964 if binding.is_import() {
3965 self.session.struct_span_err(
3966 ident.span, "cannot use a tool module through an import"
3968 binding.span, "the tool module imported here"
3971 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3972 return PathResult::NonModule(PathResolution::new(def));
3973 } else if def == Def::Err {
3974 return PathResult::NonModule(err_path_resolution());
3975 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3976 self.lint_if_path_starts_with_module(
3982 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3983 def, path.len() - i - 1
3986 return PathResult::Failed(ident.span,
3987 format!("not a module `{}`", ident),
3991 Err(Undetermined) => return PathResult::Indeterminate,
3992 Err(Determined) => {
3993 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3994 if opt_ns.is_some() && !module.is_normal() {
3995 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3996 module.def().unwrap(), path.len() - i
4000 let module_def = match module {
4001 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
4004 let msg = if module_def == self.graph_root.def() {
4005 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
4006 let mut candidates =
4007 self.lookup_import_candidates(ident, TypeNS, is_mod);
4008 candidates.sort_by_cached_key(|c| {
4009 (c.path.segments.len(), c.path.to_string())
4011 if let Some(candidate) = candidates.get(0) {
4012 format!("did you mean `{}`?", candidate.path)
4013 } else if !ident.is_reserved() {
4014 format!("maybe a missing `extern crate {};`?", ident)
4016 // the parser will already have complained about the keyword being used
4017 return PathResult::NonModule(err_path_resolution());
4020 format!("use of undeclared type or module `{}`", ident)
4022 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
4024 return PathResult::Failed(ident.span, msg, is_last);
4029 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
4031 PathResult::Module(match module {
4032 Some(module) => module,
4033 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
4034 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
4038 fn lint_if_path_starts_with_module(
4040 crate_lint: CrateLint,
4043 second_binding: Option<&NameBinding>,
4045 let (diag_id, diag_span) = match crate_lint {
4046 CrateLint::No => return,
4047 CrateLint::SimplePath(id) => (id, path_span),
4048 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
4049 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
4052 let first_name = match path.get(0) {
4053 // In the 2018 edition this lint is a hard error, so nothing to do
4054 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
4058 // We're only interested in `use` paths which should start with
4059 // `{{root}}` currently.
4060 if first_name != keywords::PathRoot.name() {
4065 // If this import looks like `crate::...` it's already good
4066 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
4067 // Otherwise go below to see if it's an extern crate
4069 // If the path has length one (and it's `PathRoot` most likely)
4070 // then we don't know whether we're gonna be importing a crate or an
4071 // item in our crate. Defer this lint to elsewhere
4075 // If the first element of our path was actually resolved to an
4076 // `ExternCrate` (also used for `crate::...`) then no need to issue a
4077 // warning, this looks all good!
4078 if let Some(binding) = second_binding {
4079 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
4080 // Careful: we still want to rewrite paths from
4081 // renamed extern crates.
4082 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
4088 let diag = lint::builtin::BuiltinLintDiagnostics
4089 ::AbsPathWithModule(diag_span);
4090 self.session.buffer_lint_with_diagnostic(
4091 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
4093 "absolute paths must start with `self`, `super`, \
4094 `crate`, or an external crate name in the 2018 edition",
4098 // Resolve a local definition, potentially adjusting for closures.
4099 fn adjust_local_def(&mut self,
4104 span: Span) -> Def {
4105 let ribs = &self.ribs[ns][rib_index + 1..];
4107 // An invalid forward use of a type parameter from a previous default.
4108 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4110 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4112 assert_eq!(def, Def::Err);
4118 span_bug!(span, "unexpected {:?} in bindings", def)
4120 Def::Local(node_id) => {
4123 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4124 ForwardTyParamBanRibKind => {
4125 // Nothing to do. Continue.
4127 ClosureRibKind(function_id) => {
4130 let seen = self.freevars_seen
4133 if let Some(&index) = seen.get(&node_id) {
4134 def = Def::Upvar(node_id, index, function_id);
4137 let vec = self.freevars
4140 let depth = vec.len();
4141 def = Def::Upvar(node_id, depth, function_id);
4148 seen.insert(node_id, depth);
4151 ItemRibKind | TraitOrImplItemRibKind => {
4152 // This was an attempt to access an upvar inside a
4153 // named function item. This is not allowed, so we
4156 resolve_error(self, span,
4157 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4161 ConstantItemRibKind => {
4162 // Still doesn't deal with upvars
4164 resolve_error(self, span,
4165 ResolutionError::AttemptToUseNonConstantValueInConstant);
4172 Def::TyParam(..) | Def::SelfTy(..) => {
4175 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4176 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4177 ConstantItemRibKind => {
4178 // Nothing to do. Continue.
4181 // This was an attempt to use a type parameter outside
4184 resolve_error(self, span,
4185 ResolutionError::TypeParametersFromOuterFunction(def));
4197 fn lookup_assoc_candidate<FilterFn>(&mut self,
4200 filter_fn: FilterFn)
4201 -> Option<AssocSuggestion>
4202 where FilterFn: Fn(Def) -> bool
4204 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4206 TyKind::Path(None, _) => Some(t.id),
4207 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4208 // This doesn't handle the remaining `Ty` variants as they are not
4209 // that commonly the self_type, it might be interesting to provide
4210 // support for those in future.
4215 // Fields are generally expected in the same contexts as locals.
4216 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4217 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4218 // Look for a field with the same name in the current self_type.
4219 if let Some(resolution) = self.def_map.get(&node_id) {
4220 match resolution.base_def() {
4221 Def::Struct(did) | Def::Union(did)
4222 if resolution.unresolved_segments() == 0 => {
4223 if let Some(field_names) = self.field_names.get(&did) {
4224 if field_names.iter().any(|&field_name| ident.name == field_name) {
4225 return Some(AssocSuggestion::Field);
4235 // Look for associated items in the current trait.
4236 if let Some((module, _)) = self.current_trait_ref {
4237 if let Ok(binding) = self.resolve_ident_in_module(
4238 ModuleOrUniformRoot::Module(module),
4245 let def = binding.def();
4247 return Some(if self.has_self.contains(&def.def_id()) {
4248 AssocSuggestion::MethodWithSelf
4250 AssocSuggestion::AssocItem
4259 fn lookup_typo_candidate<FilterFn>(
4263 filter_fn: FilterFn,
4265 ) -> Option<TypoSuggestion>
4267 FilterFn: Fn(Def) -> bool,
4269 let add_module_candidates = |module: Module, names: &mut Vec<TypoSuggestion>| {
4270 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4271 if let Some(binding) = resolution.borrow().binding {
4272 if filter_fn(binding.def()) {
4273 names.push(TypoSuggestion {
4274 candidate: ident.name,
4275 article: binding.def().article(),
4276 kind: binding.def().kind_name(),
4283 let mut names = Vec::new();
4284 if path.len() == 1 {
4285 // Search in lexical scope.
4286 // Walk backwards up the ribs in scope and collect candidates.
4287 for rib in self.ribs[ns].iter().rev() {
4288 // Locals and type parameters
4289 for (ident, def) in &rib.bindings {
4290 if filter_fn(*def) {
4291 names.push(TypoSuggestion {
4292 candidate: ident.name,
4293 article: def.article(),
4294 kind: def.kind_name(),
4299 if let ModuleRibKind(module) = rib.kind {
4300 // Items from this module
4301 add_module_candidates(module, &mut names);
4303 if let ModuleKind::Block(..) = module.kind {
4304 // We can see through blocks
4306 // Items from the prelude
4307 if !module.no_implicit_prelude {
4308 names.extend(self.extern_prelude.iter().map(|(ident, _)| {
4310 candidate: ident.name,
4315 if let Some(prelude) = self.prelude {
4316 add_module_candidates(prelude, &mut names);
4323 // Add primitive types to the mix
4324 if filter_fn(Def::PrimTy(Bool)) {
4326 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4330 kind: "primitive type",
4336 // Search in module.
4337 let mod_path = &path[..path.len() - 1];
4338 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4339 mod_path, Some(TypeNS), false, span, CrateLint::No
4341 if let ModuleOrUniformRoot::Module(module) = module {
4342 add_module_candidates(module, &mut names);
4347 let name = path[path.len() - 1].ident.name;
4348 // Make sure error reporting is deterministic.
4349 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4351 match find_best_match_for_name(
4352 names.iter().map(|suggestion| &suggestion.candidate),
4356 Some(found) if found != name => names
4358 .find(|suggestion| suggestion.candidate == found),
4363 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4364 where F: FnOnce(&mut Resolver)
4366 if let Some(label) = label {
4367 self.unused_labels.insert(id, label.ident.span);
4368 let def = Def::Label(id);
4369 self.with_label_rib(|this| {
4370 let ident = label.ident.modern_and_legacy();
4371 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4379 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4380 self.with_resolved_label(label, id, |this| this.visit_block(block));
4383 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4384 // First, record candidate traits for this expression if it could
4385 // result in the invocation of a method call.
4387 self.record_candidate_traits_for_expr_if_necessary(expr);
4389 // Next, resolve the node.
4391 ExprKind::Path(ref qself, ref path) => {
4392 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4393 visit::walk_expr(self, expr);
4396 ExprKind::Struct(ref path, ..) => {
4397 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4398 visit::walk_expr(self, expr);
4401 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4402 let def = self.search_label(label.ident, |rib, ident| {
4403 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4407 // Search again for close matches...
4408 // Picks the first label that is "close enough", which is not necessarily
4409 // the closest match
4410 let close_match = self.search_label(label.ident, |rib, ident| {
4411 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4412 find_best_match_for_name(names, &*ident.as_str(), None)
4414 self.record_def(expr.id, err_path_resolution());
4417 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4420 Some(Def::Label(id)) => {
4421 // Since this def is a label, it is never read.
4422 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4423 self.unused_labels.remove(&id);
4426 span_bug!(expr.span, "label wasn't mapped to a label def!");
4430 // visit `break` argument if any
4431 visit::walk_expr(self, expr);
4434 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4435 self.visit_expr(subexpression);
4437 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4438 let mut bindings_list = FxHashMap::default();
4440 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4442 // This has to happen *after* we determine which pat_idents are variants
4443 self.check_consistent_bindings(pats);
4444 self.visit_block(if_block);
4445 self.ribs[ValueNS].pop();
4447 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4450 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4452 ExprKind::While(ref subexpression, ref block, label) => {
4453 self.with_resolved_label(label, expr.id, |this| {
4454 this.visit_expr(subexpression);
4455 this.visit_block(block);
4459 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4460 self.with_resolved_label(label, expr.id, |this| {
4461 this.visit_expr(subexpression);
4462 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4463 let mut bindings_list = FxHashMap::default();
4465 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4467 // This has to happen *after* we determine which pat_idents are variants.
4468 this.check_consistent_bindings(pats);
4469 this.visit_block(block);
4470 this.ribs[ValueNS].pop();
4474 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4475 self.visit_expr(subexpression);
4476 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4477 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4479 self.resolve_labeled_block(label, expr.id, block);
4481 self.ribs[ValueNS].pop();
4484 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4486 // Equivalent to `visit::walk_expr` + passing some context to children.
4487 ExprKind::Field(ref subexpression, _) => {
4488 self.resolve_expr(subexpression, Some(expr));
4490 ExprKind::MethodCall(ref segment, ref arguments) => {
4491 let mut arguments = arguments.iter();
4492 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4493 for argument in arguments {
4494 self.resolve_expr(argument, None);
4496 self.visit_path_segment(expr.span, segment);
4499 ExprKind::Call(ref callee, ref arguments) => {
4500 self.resolve_expr(callee, Some(expr));
4501 for argument in arguments {
4502 self.resolve_expr(argument, None);
4505 ExprKind::Type(ref type_expr, _) => {
4506 self.current_type_ascription.push(type_expr.span);
4507 visit::walk_expr(self, expr);
4508 self.current_type_ascription.pop();
4510 // Resolve the body of async exprs inside the async closure to which they desugar
4511 ExprKind::Async(_, async_closure_id, ref block) => {
4512 let rib_kind = ClosureRibKind(async_closure_id);
4513 self.ribs[ValueNS].push(Rib::new(rib_kind));
4514 self.label_ribs.push(Rib::new(rib_kind));
4515 self.visit_block(&block);
4516 self.label_ribs.pop();
4517 self.ribs[ValueNS].pop();
4519 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4520 // resolve the arguments within the proper scopes so that usages of them inside the
4521 // closure are detected as upvars rather than normal closure arg usages.
4523 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4524 ref fn_decl, ref body, _span,
4526 let rib_kind = ClosureRibKind(expr.id);
4527 self.ribs[ValueNS].push(Rib::new(rib_kind));
4528 self.label_ribs.push(Rib::new(rib_kind));
4529 // Resolve arguments:
4530 let mut bindings_list = FxHashMap::default();
4531 for argument in &fn_decl.inputs {
4532 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4533 self.visit_ty(&argument.ty);
4535 // No need to resolve return type-- the outer closure return type is
4536 // FunctionRetTy::Default
4538 // Now resolve the inner closure
4540 let rib_kind = ClosureRibKind(inner_closure_id);
4541 self.ribs[ValueNS].push(Rib::new(rib_kind));
4542 self.label_ribs.push(Rib::new(rib_kind));
4543 // No need to resolve arguments: the inner closure has none.
4544 // Resolve the return type:
4545 visit::walk_fn_ret_ty(self, &fn_decl.output);
4547 self.visit_expr(body);
4548 self.label_ribs.pop();
4549 self.ribs[ValueNS].pop();
4551 self.label_ribs.pop();
4552 self.ribs[ValueNS].pop();
4555 visit::walk_expr(self, expr);
4560 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4562 ExprKind::Field(_, ident) => {
4563 // FIXME(#6890): Even though you can't treat a method like a
4564 // field, we need to add any trait methods we find that match
4565 // the field name so that we can do some nice error reporting
4566 // later on in typeck.
4567 let traits = self.get_traits_containing_item(ident, ValueNS);
4568 self.trait_map.insert(expr.id, traits);
4570 ExprKind::MethodCall(ref segment, ..) => {
4571 debug!("(recording candidate traits for expr) recording traits for {}",
4573 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4574 self.trait_map.insert(expr.id, traits);
4582 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4583 -> Vec<TraitCandidate> {
4584 debug!("(getting traits containing item) looking for '{}'", ident.name);
4586 let mut found_traits = Vec::new();
4587 // Look for the current trait.
4588 if let Some((module, _)) = self.current_trait_ref {
4589 if self.resolve_ident_in_module(
4590 ModuleOrUniformRoot::Module(module),
4597 let def_id = module.def_id().unwrap();
4598 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4602 ident.span = ident.span.modern();
4603 let mut search_module = self.current_module;
4605 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4606 search_module = unwrap_or!(
4607 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4611 if let Some(prelude) = self.prelude {
4612 if !search_module.no_implicit_prelude {
4613 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4620 fn get_traits_in_module_containing_item(&mut self,
4624 found_traits: &mut Vec<TraitCandidate>) {
4625 assert!(ns == TypeNS || ns == ValueNS);
4626 let mut traits = module.traits.borrow_mut();
4627 if traits.is_none() {
4628 let mut collected_traits = Vec::new();
4629 module.for_each_child(|name, ns, binding| {
4630 if ns != TypeNS { return }
4631 if let Def::Trait(_) = binding.def() {
4632 collected_traits.push((name, binding));
4635 *traits = Some(collected_traits.into_boxed_slice());
4638 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4639 let module = binding.module().unwrap();
4640 let mut ident = ident;
4641 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4644 if self.resolve_ident_in_module_unadjusted(
4645 ModuleOrUniformRoot::Module(module),
4651 let import_id = match binding.kind {
4652 NameBindingKind::Import { directive, .. } => {
4653 self.maybe_unused_trait_imports.insert(directive.id);
4654 self.add_to_glob_map(&directive, trait_name);
4659 let trait_def_id = module.def_id().unwrap();
4660 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4665 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4666 lookup_ident: Ident,
4667 namespace: Namespace,
4668 start_module: &'a ModuleData<'a>,
4670 filter_fn: FilterFn)
4671 -> Vec<ImportSuggestion>
4672 where FilterFn: Fn(Def) -> bool
4674 let mut candidates = Vec::new();
4675 let mut seen_modules = FxHashSet::default();
4676 let not_local_module = crate_name != keywords::Crate.ident();
4677 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4679 while let Some((in_module,
4681 in_module_is_extern)) = worklist.pop() {
4682 self.populate_module_if_necessary(in_module);
4684 // We have to visit module children in deterministic order to avoid
4685 // instabilities in reported imports (#43552).
4686 in_module.for_each_child_stable(|ident, ns, name_binding| {
4687 // avoid imports entirely
4688 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4689 // avoid non-importable candidates as well
4690 if !name_binding.is_importable() { return; }
4692 // collect results based on the filter function
4693 if ident.name == lookup_ident.name && ns == namespace {
4694 if filter_fn(name_binding.def()) {
4696 let mut segms = path_segments.clone();
4697 if lookup_ident.span.rust_2018() {
4698 // crate-local absolute paths start with `crate::` in edition 2018
4699 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4701 0, ast::PathSegment::from_ident(crate_name)
4705 segms.push(ast::PathSegment::from_ident(ident));
4707 span: name_binding.span,
4710 // the entity is accessible in the following cases:
4711 // 1. if it's defined in the same crate, it's always
4712 // accessible (since private entities can be made public)
4713 // 2. if it's defined in another crate, it's accessible
4714 // only if both the module is public and the entity is
4715 // declared as public (due to pruning, we don't explore
4716 // outside crate private modules => no need to check this)
4717 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4718 candidates.push(ImportSuggestion { path });
4723 // collect submodules to explore
4724 if let Some(module) = name_binding.module() {
4726 let mut path_segments = path_segments.clone();
4727 path_segments.push(ast::PathSegment::from_ident(ident));
4729 let is_extern_crate_that_also_appears_in_prelude =
4730 name_binding.is_extern_crate() &&
4731 lookup_ident.span.rust_2018();
4733 let is_visible_to_user =
4734 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4736 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4737 // add the module to the lookup
4738 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4739 if seen_modules.insert(module.def_id().unwrap()) {
4740 worklist.push((module, path_segments, is_extern));
4750 /// When name resolution fails, this method can be used to look up candidate
4751 /// entities with the expected name. It allows filtering them using the
4752 /// supplied predicate (which should be used to only accept the types of
4753 /// definitions expected e.g., traits). The lookup spans across all crates.
4755 /// NOTE: The method does not look into imports, but this is not a problem,
4756 /// since we report the definitions (thus, the de-aliased imports).
4757 fn lookup_import_candidates<FilterFn>(&mut self,
4758 lookup_ident: Ident,
4759 namespace: Namespace,
4760 filter_fn: FilterFn)
4761 -> Vec<ImportSuggestion>
4762 where FilterFn: Fn(Def) -> bool
4764 let mut suggestions = self.lookup_import_candidates_from_module(
4765 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4767 if lookup_ident.span.rust_2018() {
4768 let extern_prelude_names = self.extern_prelude.clone();
4769 for (ident, _) in extern_prelude_names.into_iter() {
4770 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4772 let crate_root = self.get_module(DefId {
4774 index: CRATE_DEF_INDEX,
4776 self.populate_module_if_necessary(&crate_root);
4778 suggestions.extend(self.lookup_import_candidates_from_module(
4779 lookup_ident, namespace, crate_root, ident, &filter_fn));
4787 fn find_module(&mut self,
4789 -> Option<(Module<'a>, ImportSuggestion)>
4791 let mut result = None;
4792 let mut seen_modules = FxHashSet::default();
4793 let mut worklist = vec![(self.graph_root, Vec::new())];
4795 while let Some((in_module, path_segments)) = worklist.pop() {
4796 // abort if the module is already found
4797 if result.is_some() { break; }
4799 self.populate_module_if_necessary(in_module);
4801 in_module.for_each_child_stable(|ident, _, name_binding| {
4802 // abort if the module is already found or if name_binding is private external
4803 if result.is_some() || !name_binding.vis.is_visible_locally() {
4806 if let Some(module) = name_binding.module() {
4808 let mut path_segments = path_segments.clone();
4809 path_segments.push(ast::PathSegment::from_ident(ident));
4810 if module.def() == Some(module_def) {
4812 span: name_binding.span,
4813 segments: path_segments,
4815 result = Some((module, ImportSuggestion { path }));
4817 // add the module to the lookup
4818 if seen_modules.insert(module.def_id().unwrap()) {
4819 worklist.push((module, path_segments));
4829 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4830 if let Def::Enum(..) = enum_def {} else {
4831 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4834 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4835 self.populate_module_if_necessary(enum_module);
4837 let mut variants = Vec::new();
4838 enum_module.for_each_child_stable(|ident, _, name_binding| {
4839 if let Def::Variant(..) = name_binding.def() {
4840 let mut segms = enum_import_suggestion.path.segments.clone();
4841 segms.push(ast::PathSegment::from_ident(ident));
4842 variants.push(Path {
4843 span: name_binding.span,
4852 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4853 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4854 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4855 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4859 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4861 ast::VisibilityKind::Public => ty::Visibility::Public,
4862 ast::VisibilityKind::Crate(..) => {
4863 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4865 ast::VisibilityKind::Inherited => {
4866 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4868 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4869 // For visibilities we are not ready to provide correct implementation of "uniform
4870 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4871 // On 2015 edition visibilities are resolved as crate-relative by default,
4872 // so we are prepending a root segment if necessary.
4873 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4874 let crate_root = if ident.is_path_segment_keyword() {
4876 } else if ident.span.rust_2018() {
4877 let msg = "relative paths are not supported in visibilities on 2018 edition";
4878 self.session.struct_span_err(ident.span, msg)
4882 format!("crate::{}", path),
4883 Applicability::MaybeIncorrect,
4886 return ty::Visibility::Public;
4888 let ctxt = ident.span.ctxt();
4889 Some(Segment::from_ident(Ident::new(
4890 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4894 let segments = crate_root.into_iter()
4895 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4896 let def = self.smart_resolve_path_fragment(
4901 PathSource::Visibility,
4902 CrateLint::SimplePath(id),
4904 if def == Def::Err {
4905 ty::Visibility::Public
4907 let vis = ty::Visibility::Restricted(def.def_id());
4908 if self.is_accessible(vis) {
4911 self.session.span_err(path.span, "visibilities can only be restricted \
4912 to ancestor modules");
4913 ty::Visibility::Public
4920 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4921 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4924 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4925 vis.is_accessible_from(module.normal_ancestor_id, self)
4928 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4929 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4930 if !ptr::eq(module, old_module) {
4931 span_bug!(binding.span, "parent module is reset for binding");
4936 fn disambiguate_legacy_vs_modern(
4938 legacy: &'a NameBinding<'a>,
4939 modern: &'a NameBinding<'a>,
4941 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4942 // is disambiguated to mitigate regressions from macro modularization.
4943 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4944 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4945 self.binding_parent_modules.get(&PtrKey(modern))) {
4946 (Some(legacy), Some(modern)) =>
4947 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4948 modern.is_ancestor_of(legacy),
4953 fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
4954 if b.span.is_dummy() {
4955 let add_built_in = match b.def() {
4956 // These already contain the "built-in" prefix or look bad with it.
4957 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4960 let (built_in, from) = if from_prelude {
4961 ("", " from prelude")
4962 } else if b.is_extern_crate() && !b.is_import() &&
4963 self.session.opts.externs.get(&ident.as_str()).is_some() {
4964 ("", " passed with `--extern`")
4965 } else if add_built_in {
4971 let article = if built_in.is_empty() { b.article() } else { "a" };
4972 format!("{a}{built_in} {thing}{from}",
4973 a = article, thing = b.descr(), built_in = built_in, from = from)
4975 let introduced = if b.is_import() { "imported" } else { "defined" };
4976 format!("the {thing} {introduced} here",
4977 thing = b.descr(), introduced = introduced)
4981 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
4982 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4983 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4984 // We have to print the span-less alternative first, otherwise formatting looks bad.
4985 (b2, b1, misc2, misc1, true)
4987 (b1, b2, misc1, misc2, false)
4990 let mut err = struct_span_err!(self.session, ident.span, E0659,
4991 "`{ident}` is ambiguous ({why})",
4992 ident = ident, why = kind.descr());
4993 err.span_label(ident.span, "ambiguous name");
4995 let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
4996 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4997 let note_msg = format!("`{ident}` could{also} refer to {what}",
4998 ident = ident, also = also, what = what);
5000 let mut help_msgs = Vec::new();
5001 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
5002 kind == AmbiguityKind::GlobVsExpanded ||
5003 kind == AmbiguityKind::GlobVsOuter &&
5004 swapped != also.is_empty()) {
5005 help_msgs.push(format!("consider adding an explicit import of \
5006 `{ident}` to disambiguate", ident = ident))
5008 if b.is_extern_crate() && ident.span.rust_2018() {
5009 help_msgs.push(format!(
5010 "use `::{ident}` to refer to this {thing} unambiguously",
5011 ident = ident, thing = b.descr(),
5014 if misc == AmbiguityErrorMisc::SuggestCrate {
5015 help_msgs.push(format!(
5016 "use `crate::{ident}` to refer to this {thing} unambiguously",
5017 ident = ident, thing = b.descr(),
5019 } else if misc == AmbiguityErrorMisc::SuggestSelf {
5020 help_msgs.push(format!(
5021 "use `self::{ident}` to refer to this {thing} unambiguously",
5022 ident = ident, thing = b.descr(),
5026 err.span_note(b.span, ¬e_msg);
5027 for (i, help_msg) in help_msgs.iter().enumerate() {
5028 let or = if i == 0 { "" } else { "or " };
5029 err.help(&format!("{}{}", or, help_msg));
5033 could_refer_to(b1, misc1, "");
5034 could_refer_to(b2, misc2, " also");
5038 fn report_errors(&mut self, krate: &Crate) {
5039 self.report_with_use_injections(krate);
5041 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
5042 let msg = "macro-expanded `macro_export` macros from the current crate \
5043 cannot be referred to by absolute paths";
5044 self.session.buffer_lint_with_diagnostic(
5045 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
5046 CRATE_NODE_ID, span_use, msg,
5047 lint::builtin::BuiltinLintDiagnostics::
5048 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
5052 for ambiguity_error in &self.ambiguity_errors {
5053 self.report_ambiguity_error(ambiguity_error);
5056 let mut reported_spans = FxHashSet::default();
5057 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
5058 if reported_spans.insert(dedup_span) {
5059 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
5060 binding.descr(), ident.name);
5065 fn report_with_use_injections(&mut self, krate: &Crate) {
5066 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5067 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5068 if !candidates.is_empty() {
5069 show_candidates(&mut err, span, &candidates, better, found_use);
5075 fn report_conflict<'b>(&mut self,
5079 new_binding: &NameBinding<'b>,
5080 old_binding: &NameBinding<'b>) {
5081 // Error on the second of two conflicting names
5082 if old_binding.span.lo() > new_binding.span.lo() {
5083 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5086 let container = match parent.kind {
5087 ModuleKind::Def(Def::Mod(_), _) => "module",
5088 ModuleKind::Def(Def::Trait(_), _) => "trait",
5089 ModuleKind::Block(..) => "block",
5093 let old_noun = match old_binding.is_import() {
5095 false => "definition",
5098 let new_participle = match new_binding.is_import() {
5103 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5105 if let Some(s) = self.name_already_seen.get(&name) {
5111 let old_kind = match (ns, old_binding.module()) {
5112 (ValueNS, _) => "value",
5113 (MacroNS, _) => "macro",
5114 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5115 (TypeNS, Some(module)) if module.is_normal() => "module",
5116 (TypeNS, Some(module)) if module.is_trait() => "trait",
5117 (TypeNS, _) => "type",
5120 let msg = format!("the name `{}` is defined multiple times", name);
5122 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5123 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5124 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5125 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5126 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5128 _ => match (old_binding.is_import(), new_binding.is_import()) {
5129 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5130 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5131 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5135 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5140 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5142 self.session.source_map().def_span(old_binding.span),
5143 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5146 // See https://github.com/rust-lang/rust/issues/32354
5147 use NameBindingKind::Import;
5148 let directive = match (&new_binding.kind, &old_binding.kind) {
5149 // If there are two imports where one or both have attributes then prefer removing the
5150 // import without attributes.
5151 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5152 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5153 (new.has_attributes || old.has_attributes)
5155 if old.has_attributes {
5156 Some((new, new_binding.span, true))
5158 Some((old, old_binding.span, true))
5161 // Otherwise prioritize the new binding.
5162 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5163 Some((directive, new_binding.span, other.is_import())),
5164 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5165 Some((directive, old_binding.span, other.is_import())),
5169 // Check if the target of the use for both bindings is the same.
5170 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5171 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5172 let from_item = self.extern_prelude.get(&ident)
5173 .map(|entry| entry.introduced_by_item)
5175 // Only suggest removing an import if both bindings are to the same def, if both spans
5176 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5177 // been introduced by a item.
5178 let should_remove_import = duplicate && !has_dummy_span &&
5179 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5182 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5183 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5184 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5185 // Simple case - remove the entire import. Due to the above match arm, this can
5186 // only be a single use so just remove it entirely.
5187 err.span_suggestion(
5188 directive.use_span_with_attributes,
5189 "remove unnecessary import",
5191 Applicability::MaybeIncorrect,
5194 Some((directive, span, _)) =>
5195 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5200 self.name_already_seen.insert(name, span);
5203 /// This function adds a suggestion to change the binding name of a new import that conflicts
5204 /// with an existing import.
5206 /// ```ignore (diagnostic)
5207 /// help: you can use `as` to change the binding name of the import
5209 /// LL | use foo::bar as other_bar;
5210 /// | ^^^^^^^^^^^^^^^^^^^^^
5212 fn add_suggestion_for_rename_of_use(
5214 err: &mut DiagnosticBuilder<'_>,
5216 directive: &ImportDirective<'_>,
5219 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5220 format!("Other{}", name)
5222 format!("other_{}", name)
5225 let mut suggestion = None;
5226 match directive.subclass {
5227 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5228 suggestion = Some(format!("self as {}", suggested_name)),
5229 ImportDirectiveSubclass::SingleImport { source, .. } => {
5230 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5231 .map(|pos| pos as usize) {
5232 if let Ok(snippet) = self.session.source_map()
5233 .span_to_snippet(binding_span) {
5234 if pos <= snippet.len() {
5235 suggestion = Some(format!(
5239 if snippet.ends_with(";") { ";" } else { "" }
5245 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5246 suggestion = Some(format!(
5247 "extern crate {} as {};",
5248 source.unwrap_or(target.name),
5251 _ => unreachable!(),
5254 let rename_msg = "you can use `as` to change the binding name of the import";
5255 if let Some(suggestion) = suggestion {
5256 err.span_suggestion(
5260 Applicability::MaybeIncorrect,
5263 err.span_label(binding_span, rename_msg);
5267 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5268 /// nested. In the following example, this function will be invoked to remove the `a` binding
5269 /// in the second use statement:
5271 /// ```ignore (diagnostic)
5272 /// use issue_52891::a;
5273 /// use issue_52891::{d, a, e};
5276 /// The following suggestion will be added:
5278 /// ```ignore (diagnostic)
5279 /// use issue_52891::{d, a, e};
5280 /// ^-- help: remove unnecessary import
5283 /// If the nested use contains only one import then the suggestion will remove the entire
5286 /// It is expected that the directive provided is a nested import - this isn't checked by the
5287 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5288 /// as characters expected by span manipulations won't be present.
5289 fn add_suggestion_for_duplicate_nested_use(
5291 err: &mut DiagnosticBuilder<'_>,
5292 directive: &ImportDirective<'_>,
5295 assert!(directive.is_nested());
5296 let message = "remove unnecessary import";
5297 let source_map = self.session.source_map();
5299 // Two examples will be used to illustrate the span manipulations we're doing:
5301 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5302 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5303 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5304 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5306 // Find the span of everything after the binding.
5307 // ie. `a, e};` or `a};`
5308 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5310 // Find everything after the binding but not including the binding.
5311 // ie. `, e};` or `};`
5312 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5314 // Keep characters in the span until we encounter something that isn't a comma or
5318 // Also note whether a closing brace character was encountered. If there
5319 // was, then later go backwards to remove any trailing commas that are left.
5320 let mut found_closing_brace = false;
5321 let after_binding_until_next_binding = source_map.span_take_while(
5322 after_binding_until_end,
5324 if ch == '}' { found_closing_brace = true; }
5325 ch == ' ' || ch == ','
5329 // Combine the two spans.
5330 // ie. `a, ` or `a`.
5332 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5333 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5335 // If there was a closing brace then identify the span to remove any trailing commas from
5336 // previous imports.
5337 if found_closing_brace {
5338 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5339 // `prev_source` will contain all of the source that came before the span.
5340 // Then split based on a command and take the first (ie. closest to our span)
5341 // snippet. In the example, this is a space.
5342 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5343 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5344 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5345 let prev_comma = prev_comma.first().unwrap();
5346 let prev_starting_brace = prev_starting_brace.first().unwrap();
5348 // If the amount of source code before the comma is greater than
5349 // the amount of source code before the starting brace then we've only
5350 // got one item in the nested item (eg. `issue_52891::{self}`).
5351 if prev_comma.len() > prev_starting_brace.len() {
5352 // So just remove the entire line...
5353 err.span_suggestion(
5354 directive.use_span_with_attributes,
5357 Applicability::MaybeIncorrect,
5362 let span = span.with_lo(BytePos(
5363 // Take away the number of bytes for the characters we've found and an
5364 // extra for the comma.
5365 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5367 err.span_suggestion(
5368 span, message, String::new(), Applicability::MaybeIncorrect,
5375 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5378 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5379 -> Option<&'a NameBinding<'a>> {
5380 if ident.is_path_segment_keyword() {
5381 // Make sure `self`, `super` etc produce an error when passed to here.
5384 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5385 if let Some(binding) = entry.extern_crate_item {
5386 if !speculative && entry.introduced_by_item {
5387 self.record_use(ident, TypeNS, binding, false);
5391 let crate_id = if !speculative {
5392 self.crate_loader.process_path_extern(ident.name, ident.span)
5393 } else if let Some(crate_id) =
5394 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5399 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5400 self.populate_module_if_necessary(&crate_root);
5401 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5402 .to_name_binding(self.arenas))
5408 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5409 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5412 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5413 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5416 fn names_to_string(idents: &[Ident]) -> String {
5417 let mut result = String::new();
5418 for (i, ident) in idents.iter()
5419 .filter(|ident| ident.name != keywords::PathRoot.name())
5422 result.push_str("::");
5424 result.push_str(&ident.as_str());
5429 fn path_names_to_string(path: &Path) -> String {
5430 names_to_string(&path.segments.iter()
5431 .map(|seg| seg.ident)
5432 .collect::<Vec<_>>())
5435 /// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5436 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5437 let variant_path = &suggestion.path;
5438 let variant_path_string = path_names_to_string(variant_path);
5440 let path_len = suggestion.path.segments.len();
5441 let enum_path = ast::Path {
5442 span: suggestion.path.span,
5443 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5445 let enum_path_string = path_names_to_string(&enum_path);
5447 (variant_path_string, enum_path_string)
5451 /// When an entity with a given name is not available in scope, we search for
5452 /// entities with that name in all crates. This method allows outputting the
5453 /// results of this search in a programmer-friendly way
5454 fn show_candidates(err: &mut DiagnosticBuilder,
5455 // This is `None` if all placement locations are inside expansions
5457 candidates: &[ImportSuggestion],
5461 // we want consistent results across executions, but candidates are produced
5462 // by iterating through a hash map, so make sure they are ordered:
5463 let mut path_strings: Vec<_> =
5464 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5465 path_strings.sort();
5467 let better = if better { "better " } else { "" };
5468 let msg_diff = match path_strings.len() {
5469 1 => " is found in another module, you can import it",
5470 _ => "s are found in other modules, you can import them",
5472 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5474 if let Some(span) = span {
5475 for candidate in &mut path_strings {
5476 // produce an additional newline to separate the new use statement
5477 // from the directly following item.
5478 let additional_newline = if found_use {
5483 *candidate = format!("use {};\n{}", candidate, additional_newline);
5486 err.span_suggestions(
5489 path_strings.into_iter(),
5490 Applicability::Unspecified,
5495 for candidate in path_strings {
5497 msg.push_str(&candidate);
5502 /// A somewhat inefficient routine to obtain the name of a module.
5503 fn module_to_string(module: Module) -> Option<String> {
5504 let mut names = Vec::new();
5506 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5507 if let ModuleKind::Def(_, name) = module.kind {
5508 if let Some(parent) = module.parent {
5509 names.push(Ident::with_empty_ctxt(name));
5510 collect_mod(names, parent);
5513 // danger, shouldn't be ident?
5514 names.push(Ident::from_str("<opaque>"));
5515 collect_mod(names, module.parent.unwrap());
5518 collect_mod(&mut names, module);
5520 if names.is_empty() {
5523 Some(names_to_string(&names.into_iter()
5525 .collect::<Vec<_>>()))
5528 fn err_path_resolution() -> PathResolution {
5529 PathResolution::new(Def::Err)
5532 #[derive(Copy, Clone, Debug)]
5534 /// Do not issue the lint
5537 /// This lint applies to some random path like `impl ::foo::Bar`
5538 /// or whatever. In this case, we can take the span of that path.
5541 /// This lint comes from a `use` statement. In this case, what we
5542 /// care about really is the *root* `use` statement; e.g., if we
5543 /// have nested things like `use a::{b, c}`, we care about the
5545 UsePath { root_id: NodeId, root_span: Span },
5547 /// This is the "trait item" from a fully qualified path. For example,
5548 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5549 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5550 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5554 fn node_id(&self) -> Option<NodeId> {
5556 CrateLint::No => None,
5557 CrateLint::SimplePath(id) |
5558 CrateLint::UsePath { root_id: id, .. } |
5559 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5564 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }