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::{Span, DUMMY_SP, MultiSpan};
67 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
69 use std::cell::{Cell, RefCell};
70 use std::{cmp, fmt, iter, 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 impl PartialOrd for BindingError {
124 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
125 Some(self.cmp(other))
129 impl PartialEq for BindingError {
130 fn eq(&self, other: &BindingError) -> bool {
131 self.name == other.name
135 impl Ord for BindingError {
136 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
137 self.name.cmp(&other.name)
141 enum ResolutionError<'a> {
142 /// error E0401: can't use type parameters from outer function
143 TypeParametersFromOuterFunction(Def),
144 /// error E0403: the name is already used for a type parameter in this type parameter list
145 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
146 /// error E0407: method is not a member of trait
147 MethodNotMemberOfTrait(Name, &'a str),
148 /// error E0437: type is not a member of trait
149 TypeNotMemberOfTrait(Name, &'a str),
150 /// error E0438: const is not a member of trait
151 ConstNotMemberOfTrait(Name, &'a str),
152 /// error E0408: variable `{}` is not bound in all patterns
153 VariableNotBoundInPattern(&'a BindingError),
154 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
155 VariableBoundWithDifferentMode(Name, Span),
156 /// error E0415: identifier is bound more than once in this parameter list
157 IdentifierBoundMoreThanOnceInParameterList(&'a str),
158 /// error E0416: identifier is bound more than once in the same pattern
159 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
160 /// error E0426: use of undeclared label
161 UndeclaredLabel(&'a str, Option<Name>),
162 /// error E0429: `self` imports are only allowed within a { } list
163 SelfImportsOnlyAllowedWithin,
164 /// error E0430: `self` import can only appear once in the list
165 SelfImportCanOnlyAppearOnceInTheList,
166 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
167 SelfImportOnlyInImportListWithNonEmptyPrefix,
168 /// error E0433: failed to resolve
169 FailedToResolve(&'a str),
170 /// error E0434: can't capture dynamic environment in a fn item
171 CannotCaptureDynamicEnvironmentInFnItem,
172 /// error E0435: attempt to use a non-constant value in a constant
173 AttemptToUseNonConstantValueInConstant,
174 /// error E0530: X bindings cannot shadow Ys
175 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
176 /// error E0128: type parameters with a default cannot use forward declared identifiers
177 ForwardDeclaredTyParam,
180 /// Combines an error with provided span and emits it
182 /// This takes the error provided, combines it with the span and any additional spans inside the
183 /// error and emits it.
184 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
186 resolution_error: ResolutionError<'a>) {
187 resolve_struct_error(resolver, span, resolution_error).emit();
190 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
192 resolution_error: ResolutionError<'a>)
193 -> DiagnosticBuilder<'sess> {
194 match resolution_error {
195 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
196 let mut err = struct_span_err!(resolver.session,
199 "can't use type parameters from outer function");
200 err.span_label(span, "use of type variable from outer function");
202 let cm = resolver.session.source_map();
204 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
205 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
206 resolver.definitions.opt_span(def_id)
209 reduce_impl_span_to_impl_keyword(cm, impl_span),
210 "`Self` type implicitly declared here, by this `impl`",
213 match (maybe_trait_defid, maybe_impl_defid) {
215 err.span_label(span, "can't use `Self` here");
218 err.span_label(span, "use a type here instead");
220 (None, None) => bug!("`impl` without trait nor type?"),
224 Def::TyParam(typaram_defid) => {
225 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
226 err.span_label(typaram_span, "type variable from outer function");
230 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
235 // Try to retrieve the span of the function signature and generate a new message with
236 // a local type parameter
237 let sugg_msg = "try using a local type parameter instead";
238 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
239 // Suggest the modification to the user
240 err.span_suggestion_with_applicability(
244 Applicability::MachineApplicable,
246 } else if let Some(sp) = cm.generate_fn_name_span(span) {
247 err.span_label(sp, "try adding a local type parameter in this method instead");
249 err.help("try using a local type parameter instead");
254 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
255 let mut err = struct_span_err!(resolver.session,
258 "the name `{}` is already used for a type parameter \
259 in this type parameter list",
261 err.span_label(span, "already used");
262 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
265 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
266 let mut err = struct_span_err!(resolver.session,
269 "method `{}` is not a member of trait `{}`",
272 err.span_label(span, format!("not a member of trait `{}`", trait_));
275 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
276 let mut err = struct_span_err!(resolver.session,
279 "type `{}` is not a member of trait `{}`",
282 err.span_label(span, format!("not a member of trait `{}`", trait_));
285 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
286 let mut err = struct_span_err!(resolver.session,
289 "const `{}` is not a member of trait `{}`",
292 err.span_label(span, format!("not a member of trait `{}`", trait_));
295 ResolutionError::VariableNotBoundInPattern(binding_error) => {
296 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
297 let msp = MultiSpan::from_spans(target_sp.clone());
298 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
299 let mut err = resolver.session.struct_span_err_with_code(
302 DiagnosticId::Error("E0408".into()),
304 for sp in target_sp {
305 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
307 let origin_sp = binding_error.origin.iter().cloned();
308 for sp in origin_sp {
309 err.span_label(sp, "variable not in all patterns");
313 ResolutionError::VariableBoundWithDifferentMode(variable_name,
314 first_binding_span) => {
315 let mut err = struct_span_err!(resolver.session,
318 "variable `{}` is bound in inconsistent \
319 ways within the same match arm",
321 err.span_label(span, "bound in different ways");
322 err.span_label(first_binding_span, "first binding");
325 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
326 let mut err = struct_span_err!(resolver.session,
329 "identifier `{}` is bound more than once in this parameter list",
331 err.span_label(span, "used as parameter more than once");
334 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
335 let mut err = struct_span_err!(resolver.session,
338 "identifier `{}` is bound more than once in the same pattern",
340 err.span_label(span, "used in a pattern more than once");
343 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
344 let mut err = struct_span_err!(resolver.session,
347 "use of undeclared label `{}`",
349 if let Some(lev_candidate) = lev_candidate {
350 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
352 err.span_label(span, format!("undeclared label `{}`", name));
356 ResolutionError::SelfImportsOnlyAllowedWithin => {
357 struct_span_err!(resolver.session,
361 "`self` imports are only allowed within a { } list")
363 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
364 let mut err = struct_span_err!(resolver.session, span, E0430,
365 "`self` import can only appear once in an import list");
366 err.span_label(span, "can only appear once in an import list");
369 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
370 let mut err = struct_span_err!(resolver.session, span, E0431,
371 "`self` import can only appear in an import list with \
372 a non-empty prefix");
373 err.span_label(span, "can only appear in an import list with a non-empty prefix");
376 ResolutionError::FailedToResolve(msg) => {
377 let mut err = struct_span_err!(resolver.session, span, E0433,
378 "failed to resolve: {}", msg);
379 err.span_label(span, msg);
382 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
383 let mut err = struct_span_err!(resolver.session,
387 "can't capture dynamic environment in a fn item");
388 err.help("use the `|| { ... }` closure form instead");
391 ResolutionError::AttemptToUseNonConstantValueInConstant => {
392 let mut err = struct_span_err!(resolver.session, span, E0435,
393 "attempt to use a non-constant value in a constant");
394 err.span_label(span, "non-constant value");
397 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
398 let shadows_what = binding.descr();
399 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
400 what_binding, shadows_what);
401 err.span_label(span, format!("cannot be named the same as {} {}",
402 binding.article(), shadows_what));
403 let participle = if binding.is_import() { "imported" } else { "defined" };
404 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
405 err.span_label(binding.span, msg);
408 ResolutionError::ForwardDeclaredTyParam => {
409 let mut err = struct_span_err!(resolver.session, span, E0128,
410 "type parameters with a default cannot use \
411 forward declared identifiers");
413 span, "defaulted type parameters cannot be forward declared".to_string());
419 /// Adjust the impl span so that just the `impl` keyword is taken by removing
420 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
421 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
423 /// Attention: The method used is very fragile since it essentially duplicates the work of the
424 /// parser. If you need to use this function or something similar, please consider updating the
425 /// source_map functions and this function to something more robust.
426 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
427 let impl_span = cm.span_until_char(impl_span, '<');
428 let impl_span = cm.span_until_whitespace(impl_span);
432 #[derive(Copy, Clone, Debug)]
435 binding_mode: BindingMode,
438 /// Map from the name in a pattern to its binding mode.
439 type BindingMap = FxHashMap<Ident, BindingInfo>;
441 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
452 fn descr(self) -> &'static str {
454 PatternSource::Match => "match binding",
455 PatternSource::IfLet => "if let binding",
456 PatternSource::WhileLet => "while let binding",
457 PatternSource::Let => "let binding",
458 PatternSource::For => "for binding",
459 PatternSource::FnParam => "function parameter",
464 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
465 enum AliasPossibility {
470 #[derive(Copy, Clone, Debug)]
471 enum PathSource<'a> {
472 // Type paths `Path`.
474 // Trait paths in bounds or impls.
475 Trait(AliasPossibility),
476 // Expression paths `path`, with optional parent context.
477 Expr(Option<&'a Expr>),
478 // Paths in path patterns `Path`.
480 // Paths in struct expressions and patterns `Path { .. }`.
482 // Paths in tuple struct patterns `Path(..)`.
484 // `m::A::B` in `<T as m::A>::B::C`.
485 TraitItem(Namespace),
486 // Path in `pub(path)`
490 impl<'a> PathSource<'a> {
491 fn namespace(self) -> Namespace {
493 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
494 PathSource::Visibility => TypeNS,
495 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
496 PathSource::TraitItem(ns) => ns,
500 fn global_by_default(self) -> bool {
502 PathSource::Visibility => true,
503 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
504 PathSource::Struct | PathSource::TupleStruct |
505 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
509 fn defer_to_typeck(self) -> bool {
511 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
512 PathSource::Struct | PathSource::TupleStruct => true,
513 PathSource::Trait(_) | PathSource::TraitItem(..) |
514 PathSource::Visibility => false,
518 fn descr_expected(self) -> &'static str {
520 PathSource::Type => "type",
521 PathSource::Trait(_) => "trait",
522 PathSource::Pat => "unit struct/variant or constant",
523 PathSource::Struct => "struct, variant or union type",
524 PathSource::TupleStruct => "tuple struct/variant",
525 PathSource::Visibility => "module",
526 PathSource::TraitItem(ns) => match ns {
527 TypeNS => "associated type",
528 ValueNS => "method or associated constant",
529 MacroNS => bug!("associated macro"),
531 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
532 // "function" here means "anything callable" rather than `Def::Fn`,
533 // this is not precise but usually more helpful than just "value".
534 Some(&ExprKind::Call(..)) => "function",
540 fn is_expected(self, def: Def) -> bool {
542 PathSource::Type => match def {
543 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
544 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
545 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
546 Def::SelfTy(..) | Def::Existential(..) |
547 Def::ForeignTy(..) => true,
550 PathSource::Trait(AliasPossibility::No) => match def {
551 Def::Trait(..) => true,
554 PathSource::Trait(AliasPossibility::Maybe) => match def {
555 Def::Trait(..) => true,
556 Def::TraitAlias(..) => true,
559 PathSource::Expr(..) => match def {
560 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
561 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
562 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
563 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
564 Def::SelfCtor(..) => true,
567 PathSource::Pat => match def {
568 Def::StructCtor(_, CtorKind::Const) |
569 Def::VariantCtor(_, CtorKind::Const) |
570 Def::Const(..) | Def::AssociatedConst(..) |
571 Def::SelfCtor(..) => true,
574 PathSource::TupleStruct => match def {
575 Def::StructCtor(_, CtorKind::Fn) |
576 Def::VariantCtor(_, CtorKind::Fn) |
577 Def::SelfCtor(..) => true,
580 PathSource::Struct => match def {
581 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
582 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
585 PathSource::TraitItem(ns) => match def {
586 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
587 Def::AssociatedTy(..) if ns == TypeNS => true,
590 PathSource::Visibility => match def {
591 Def::Mod(..) => true,
597 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
598 __diagnostic_used!(E0404);
599 __diagnostic_used!(E0405);
600 __diagnostic_used!(E0412);
601 __diagnostic_used!(E0422);
602 __diagnostic_used!(E0423);
603 __diagnostic_used!(E0425);
604 __diagnostic_used!(E0531);
605 __diagnostic_used!(E0532);
606 __diagnostic_used!(E0573);
607 __diagnostic_used!(E0574);
608 __diagnostic_used!(E0575);
609 __diagnostic_used!(E0576);
610 __diagnostic_used!(E0577);
611 __diagnostic_used!(E0578);
612 match (self, has_unexpected_resolution) {
613 (PathSource::Trait(_), true) => "E0404",
614 (PathSource::Trait(_), false) => "E0405",
615 (PathSource::Type, true) => "E0573",
616 (PathSource::Type, false) => "E0412",
617 (PathSource::Struct, true) => "E0574",
618 (PathSource::Struct, false) => "E0422",
619 (PathSource::Expr(..), true) => "E0423",
620 (PathSource::Expr(..), false) => "E0425",
621 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
622 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
623 (PathSource::TraitItem(..), true) => "E0575",
624 (PathSource::TraitItem(..), false) => "E0576",
625 (PathSource::Visibility, true) => "E0577",
626 (PathSource::Visibility, false) => "E0578",
631 // A minimal representation of a path segment. We use this in resolve because
632 // we synthesize 'path segments' which don't have the rest of an AST or HIR
634 #[derive(Clone, Copy, Debug)]
641 fn from_path(path: &Path) -> Vec<Segment> {
642 path.segments.iter().map(|s| s.into()).collect()
645 fn from_ident(ident: Ident) -> Segment {
652 fn names_to_string(segments: &[Segment]) -> String {
653 names_to_string(&segments.iter()
654 .map(|seg| seg.ident)
655 .collect::<Vec<_>>())
659 impl<'a> From<&'a ast::PathSegment> for Segment {
660 fn from(seg: &'a ast::PathSegment) -> Segment {
668 struct UsePlacementFinder {
669 target_module: NodeId,
674 impl UsePlacementFinder {
675 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
676 let mut finder = UsePlacementFinder {
681 visit::walk_crate(&mut finder, krate);
682 (finder.span, finder.found_use)
686 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
689 module: &'tcx ast::Mod,
691 _: &[ast::Attribute],
694 if self.span.is_some() {
697 if node_id != self.target_module {
698 visit::walk_mod(self, module);
701 // find a use statement
702 for item in &module.items {
704 ItemKind::Use(..) => {
705 // don't suggest placing a use before the prelude
706 // import or other generated ones
707 if item.span.ctxt().outer().expn_info().is_none() {
708 self.span = Some(item.span.shrink_to_lo());
709 self.found_use = true;
713 // don't place use before extern crate
714 ItemKind::ExternCrate(_) => {}
715 // but place them before the first other item
716 _ => if self.span.map_or(true, |span| item.span < span ) {
717 if item.span.ctxt().outer().expn_info().is_none() {
718 // don't insert between attributes and an item
719 if item.attrs.is_empty() {
720 self.span = Some(item.span.shrink_to_lo());
722 // find the first attribute on the item
723 for attr in &item.attrs {
724 if self.span.map_or(true, |span| attr.span < span) {
725 self.span = Some(attr.span.shrink_to_lo());
736 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
737 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
738 fn visit_item(&mut self, item: &'tcx Item) {
739 self.resolve_item(item);
741 fn visit_arm(&mut self, arm: &'tcx Arm) {
742 self.resolve_arm(arm);
744 fn visit_block(&mut self, block: &'tcx Block) {
745 self.resolve_block(block);
747 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
748 self.with_constant_rib(|this| {
749 visit::walk_anon_const(this, constant);
752 fn visit_expr(&mut self, expr: &'tcx Expr) {
753 self.resolve_expr(expr, None);
755 fn visit_local(&mut self, local: &'tcx Local) {
756 self.resolve_local(local);
758 fn visit_ty(&mut self, ty: &'tcx Ty) {
760 TyKind::Path(ref qself, ref path) => {
761 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
763 TyKind::ImplicitSelf => {
764 let self_ty = keywords::SelfUpper.ident();
765 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
766 .map_or(Def::Err, |d| d.def());
767 self.record_def(ty.id, PathResolution::new(def));
771 visit::walk_ty(self, ty);
773 fn visit_poly_trait_ref(&mut self,
774 tref: &'tcx ast::PolyTraitRef,
775 m: &'tcx ast::TraitBoundModifier) {
776 self.smart_resolve_path(tref.trait_ref.ref_id, None,
777 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
778 visit::walk_poly_trait_ref(self, tref, m);
780 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
781 let type_parameters = match foreign_item.node {
782 ForeignItemKind::Fn(_, ref generics) => {
783 HasTypeParameters(generics, ItemRibKind)
785 ForeignItemKind::Static(..) => NoTypeParameters,
786 ForeignItemKind::Ty => NoTypeParameters,
787 ForeignItemKind::Macro(..) => NoTypeParameters,
789 self.with_type_parameter_rib(type_parameters, |this| {
790 visit::walk_foreign_item(this, foreign_item);
793 fn visit_fn(&mut self,
794 function_kind: FnKind<'tcx>,
795 declaration: &'tcx FnDecl,
799 let (rib_kind, asyncness) = match function_kind {
800 FnKind::ItemFn(_, ref header, ..) =>
801 (ItemRibKind, header.asyncness),
802 FnKind::Method(_, ref sig, _, _) =>
803 (TraitOrImplItemRibKind, sig.header.asyncness),
804 FnKind::Closure(_) =>
805 // Async closures aren't resolved through `visit_fn`-- they're
806 // processed separately
807 (ClosureRibKind(node_id), IsAsync::NotAsync),
810 // Create a value rib for the function.
811 self.ribs[ValueNS].push(Rib::new(rib_kind));
813 // Create a label rib for the function.
814 self.label_ribs.push(Rib::new(rib_kind));
816 // Add each argument to the rib.
817 let mut bindings_list = FxHashMap::default();
818 for argument in &declaration.inputs {
819 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
821 self.visit_ty(&argument.ty);
823 debug!("(resolving function) recorded argument");
825 visit::walk_fn_ret_ty(self, &declaration.output);
827 // Resolve the function body, potentially inside the body of an async closure
828 if let IsAsync::Async { closure_id, .. } = asyncness {
829 let rib_kind = ClosureRibKind(closure_id);
830 self.ribs[ValueNS].push(Rib::new(rib_kind));
831 self.label_ribs.push(Rib::new(rib_kind));
834 match function_kind {
835 FnKind::ItemFn(.., body) |
836 FnKind::Method(.., body) => {
837 self.visit_block(body);
839 FnKind::Closure(body) => {
840 self.visit_expr(body);
844 // Leave the body of the async closure
845 if asyncness.is_async() {
846 self.label_ribs.pop();
847 self.ribs[ValueNS].pop();
850 debug!("(resolving function) leaving function");
852 self.label_ribs.pop();
853 self.ribs[ValueNS].pop();
855 fn visit_generics(&mut self, generics: &'tcx Generics) {
856 // For type parameter defaults, we have to ban access
857 // to following type parameters, as the Substs can only
858 // provide previous type parameters as they're built. We
859 // put all the parameters on the ban list and then remove
860 // them one by one as they are processed and become available.
861 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
862 let mut found_default = false;
863 default_ban_rib.bindings.extend(generics.params.iter()
864 .filter_map(|param| match param.kind {
865 GenericParamKind::Lifetime { .. } => None,
866 GenericParamKind::Type { ref default, .. } => {
867 found_default |= default.is_some();
869 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
876 for param in &generics.params {
878 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
879 GenericParamKind::Type { ref default, .. } => {
880 for bound in ¶m.bounds {
881 self.visit_param_bound(bound);
884 if let Some(ref ty) = default {
885 self.ribs[TypeNS].push(default_ban_rib);
887 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
890 // Allow all following defaults to refer to this type parameter.
891 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
895 for p in &generics.where_clause.predicates {
896 self.visit_where_predicate(p);
901 #[derive(Copy, Clone)]
902 enum TypeParameters<'a, 'b> {
904 HasTypeParameters(// Type parameters.
907 // The kind of the rib used for type parameters.
911 /// The rib kind controls the translation of local
912 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
913 #[derive(Copy, Clone, Debug)]
915 /// No translation needs to be applied.
918 /// We passed through a closure scope at the given node ID.
919 /// Translate upvars as appropriate.
920 ClosureRibKind(NodeId /* func id */),
922 /// We passed through an impl or trait and are now in one of its
923 /// methods or associated types. Allow references to ty params that impl or trait
924 /// binds. Disallow any other upvars (including other ty params that are
926 TraitOrImplItemRibKind,
928 /// We passed through an item scope. Disallow upvars.
931 /// We're in a constant item. Can't refer to dynamic stuff.
934 /// We passed through a module.
935 ModuleRibKind(Module<'a>),
937 /// We passed through a `macro_rules!` statement
938 MacroDefinition(DefId),
940 /// All bindings in this rib are type parameters that can't be used
941 /// from the default of a type parameter because they're not declared
942 /// before said type parameter. Also see the `visit_generics` override.
943 ForwardTyParamBanRibKind,
948 /// A rib represents a scope names can live in. Note that these appear in many places, not just
949 /// around braces. At any place where the list of accessible names (of the given namespace)
950 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
951 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
954 /// Different [rib kinds](enum.RibKind) are transparent for different names.
956 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
957 /// resolving, the name is looked up from inside out.
960 bindings: FxHashMap<Ident, Def>,
965 fn new(kind: RibKind<'a>) -> Rib<'a> {
967 bindings: Default::default(),
973 /// An intermediate resolution result.
975 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
976 /// items are visible in their whole block, while defs only from the place they are defined
978 enum LexicalScopeBinding<'a> {
979 Item(&'a NameBinding<'a>),
983 impl<'a> LexicalScopeBinding<'a> {
984 fn item(self) -> Option<&'a NameBinding<'a>> {
986 LexicalScopeBinding::Item(binding) => Some(binding),
991 fn def(self) -> Def {
993 LexicalScopeBinding::Item(binding) => binding.def(),
994 LexicalScopeBinding::Def(def) => def,
999 #[derive(Copy, Clone, Debug)]
1000 enum ModuleOrUniformRoot<'a> {
1004 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1005 CrateRootAndExternPrelude,
1007 /// Virtual module that denotes resolution in extern prelude.
1008 /// Used for paths starting with `::` on 2018 edition or `extern::`.
1011 /// Virtual module that denotes resolution in current scope.
1012 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1013 /// are always split into two parts, the first of which should be some kind of module.
1017 impl ModuleOrUniformRoot<'_> {
1018 fn same_def(lhs: Self, rhs: Self) -> bool {
1020 (ModuleOrUniformRoot::Module(lhs),
1021 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1022 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1023 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1024 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1025 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1031 #[derive(Clone, Debug)]
1032 enum PathResult<'a> {
1033 Module(ModuleOrUniformRoot<'a>),
1034 NonModule(PathResolution),
1036 Failed(Span, String, bool /* is the error from the last segment? */),
1040 /// An anonymous module, eg. just a block.
1044 /// fn f() {} // (1)
1045 /// { // This is an anonymous module
1046 /// f(); // This resolves to (2) as we are inside the block.
1047 /// fn f() {} // (2)
1049 /// f(); // Resolves to (1)
1053 /// Any module with a name.
1057 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1058 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1063 /// One node in the tree of modules.
1064 pub struct ModuleData<'a> {
1065 parent: Option<Module<'a>>,
1068 // The def id of the closest normal module (`mod`) ancestor (including this module).
1069 normal_ancestor_id: DefId,
1071 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1072 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1073 Option<&'a NameBinding<'a>>)>>,
1074 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1076 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1078 // Macro invocations that can expand into items in this module.
1079 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1081 no_implicit_prelude: bool,
1083 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1084 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1086 // Used to memoize the traits in this module for faster searches through all traits in scope.
1087 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1089 // Whether this module is populated. If not populated, any attempt to
1090 // access the children must be preceded with a
1091 // `populate_module_if_necessary` call.
1092 populated: Cell<bool>,
1094 /// Span of the module itself. Used for error reporting.
1100 type Module<'a> = &'a ModuleData<'a>;
1102 impl<'a> ModuleData<'a> {
1103 fn new(parent: Option<Module<'a>>,
1105 normal_ancestor_id: DefId,
1107 span: Span) -> Self {
1112 resolutions: Default::default(),
1113 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1114 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1115 builtin_attrs: RefCell::new(Vec::new()),
1116 unresolved_invocations: Default::default(),
1117 no_implicit_prelude: false,
1118 glob_importers: RefCell::new(Vec::new()),
1119 globs: RefCell::new(Vec::new()),
1120 traits: RefCell::new(None),
1121 populated: Cell::new(normal_ancestor_id.is_local()),
1127 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1128 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1129 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1133 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1134 let resolutions = self.resolutions.borrow();
1135 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1136 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1137 for &(&(ident, ns), &resolution) in resolutions.iter() {
1138 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1142 fn def(&self) -> Option<Def> {
1144 ModuleKind::Def(def, _) => Some(def),
1149 fn def_id(&self) -> Option<DefId> {
1150 self.def().as_ref().map(Def::def_id)
1153 // `self` resolves to the first module ancestor that `is_normal`.
1154 fn is_normal(&self) -> bool {
1156 ModuleKind::Def(Def::Mod(_), _) => true,
1161 fn is_trait(&self) -> bool {
1163 ModuleKind::Def(Def::Trait(_), _) => true,
1168 fn nearest_item_scope(&'a self) -> Module<'a> {
1169 if self.is_trait() { self.parent.unwrap() } else { self }
1172 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1173 while !ptr::eq(self, other) {
1174 if let Some(parent) = other.parent {
1184 impl<'a> fmt::Debug for ModuleData<'a> {
1185 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1186 write!(f, "{:?}", self.def())
1190 /// Records a possibly-private value, type, or module definition.
1191 #[derive(Clone, Debug)]
1192 pub struct NameBinding<'a> {
1193 kind: NameBindingKind<'a>,
1194 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1197 vis: ty::Visibility,
1200 pub trait ToNameBinding<'a> {
1201 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1204 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1205 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1210 #[derive(Clone, Debug)]
1211 enum NameBindingKind<'a> {
1212 Def(Def, /* is_macro_export */ bool),
1215 binding: &'a NameBinding<'a>,
1216 directive: &'a ImportDirective<'a>,
1221 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1223 struct UseError<'a> {
1224 err: DiagnosticBuilder<'a>,
1225 /// Attach `use` statements for these candidates
1226 candidates: Vec<ImportSuggestion>,
1227 /// The node id of the module to place the use statements in
1229 /// Whether the diagnostic should state that it's "better"
1233 #[derive(Clone, Copy, PartialEq, Debug)]
1234 enum AmbiguityKind {
1239 LegacyHelperVsPrelude,
1244 MoreExpandedVsOuter,
1247 impl AmbiguityKind {
1248 fn descr(self) -> &'static str {
1250 AmbiguityKind::Import =>
1251 "name vs any other name during import resolution",
1252 AmbiguityKind::AbsolutePath =>
1253 "name in the crate root vs extern crate during absolute path resolution",
1254 AmbiguityKind::BuiltinAttr =>
1255 "built-in attribute vs any other name",
1256 AmbiguityKind::DeriveHelper =>
1257 "derive helper attribute vs any other name",
1258 AmbiguityKind::LegacyHelperVsPrelude =>
1259 "legacy plugin helper attribute vs name from prelude",
1260 AmbiguityKind::LegacyVsModern =>
1261 "`macro_rules` vs non-`macro_rules` from other module",
1262 AmbiguityKind::GlobVsOuter =>
1263 "glob import vs any other name from outer scope during import/macro resolution",
1264 AmbiguityKind::GlobVsGlob =>
1265 "glob import vs glob import in the same module",
1266 AmbiguityKind::GlobVsExpanded =>
1267 "glob import vs macro-expanded name in the same \
1268 module during import/macro resolution",
1269 AmbiguityKind::MoreExpandedVsOuter =>
1270 "macro-expanded name vs less macro-expanded name \
1271 from outer scope during import/macro resolution",
1276 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1277 #[derive(Clone, Copy, PartialEq)]
1278 enum AmbiguityErrorMisc {
1285 struct AmbiguityError<'a> {
1286 kind: AmbiguityKind,
1288 b1: &'a NameBinding<'a>,
1289 b2: &'a NameBinding<'a>,
1290 misc1: AmbiguityErrorMisc,
1291 misc2: AmbiguityErrorMisc,
1294 impl<'a> NameBinding<'a> {
1295 fn module(&self) -> Option<Module<'a>> {
1297 NameBindingKind::Module(module) => Some(module),
1298 NameBindingKind::Import { binding, .. } => binding.module(),
1303 fn def(&self) -> Def {
1305 NameBindingKind::Def(def, _) => def,
1306 NameBindingKind::Module(module) => module.def().unwrap(),
1307 NameBindingKind::Import { binding, .. } => binding.def(),
1311 fn is_ambiguity(&self) -> bool {
1312 self.ambiguity.is_some() || match self.kind {
1313 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1318 // We sometimes need to treat variants as `pub` for backwards compatibility
1319 fn pseudo_vis(&self) -> ty::Visibility {
1320 if self.is_variant() && self.def().def_id().is_local() {
1321 ty::Visibility::Public
1327 fn is_variant(&self) -> bool {
1329 NameBindingKind::Def(Def::Variant(..), _) |
1330 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1335 fn is_extern_crate(&self) -> bool {
1337 NameBindingKind::Import {
1338 directive: &ImportDirective {
1339 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1342 NameBindingKind::Module(
1343 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1344 ) => def_id.index == CRATE_DEF_INDEX,
1349 fn is_import(&self) -> bool {
1351 NameBindingKind::Import { .. } => true,
1356 fn is_glob_import(&self) -> bool {
1358 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1363 fn is_importable(&self) -> bool {
1365 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1370 fn is_macro_def(&self) -> bool {
1372 NameBindingKind::Def(Def::Macro(..), _) => true,
1377 fn macro_kind(&self) -> Option<MacroKind> {
1379 Def::Macro(_, kind) => Some(kind),
1380 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1385 fn descr(&self) -> &'static str {
1386 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1389 fn article(&self) -> &'static str {
1390 if self.is_extern_crate() { "an" } else { self.def().article() }
1393 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1394 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1395 // Then this function returns `true` if `self` may emerge from a macro *after* that
1396 // in some later round and screw up our previously found resolution.
1397 // See more detailed explanation in
1398 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1399 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1400 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1401 // Expansions are partially ordered, so "may appear after" is an inversion of
1402 // "certainly appears before or simultaneously" and includes unordered cases.
1403 let self_parent_expansion = self.expansion;
1404 let other_parent_expansion = binding.expansion;
1405 let certainly_before_other_or_simultaneously =
1406 other_parent_expansion.is_descendant_of(self_parent_expansion);
1407 let certainly_before_invoc_or_simultaneously =
1408 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1409 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1413 /// Interns the names of the primitive types.
1415 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1416 /// special handling, since they have no place of origin.
1418 struct PrimitiveTypeTable {
1419 primitive_types: FxHashMap<Name, PrimTy>,
1422 impl PrimitiveTypeTable {
1423 fn new() -> PrimitiveTypeTable {
1424 let mut table = PrimitiveTypeTable::default();
1426 table.intern("bool", Bool);
1427 table.intern("char", Char);
1428 table.intern("f32", Float(FloatTy::F32));
1429 table.intern("f64", Float(FloatTy::F64));
1430 table.intern("isize", Int(IntTy::Isize));
1431 table.intern("i8", Int(IntTy::I8));
1432 table.intern("i16", Int(IntTy::I16));
1433 table.intern("i32", Int(IntTy::I32));
1434 table.intern("i64", Int(IntTy::I64));
1435 table.intern("i128", Int(IntTy::I128));
1436 table.intern("str", Str);
1437 table.intern("usize", Uint(UintTy::Usize));
1438 table.intern("u8", Uint(UintTy::U8));
1439 table.intern("u16", Uint(UintTy::U16));
1440 table.intern("u32", Uint(UintTy::U32));
1441 table.intern("u64", Uint(UintTy::U64));
1442 table.intern("u128", Uint(UintTy::U128));
1446 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1447 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1451 #[derive(Default, Clone)]
1452 pub struct ExternPreludeEntry<'a> {
1453 extern_crate_item: Option<&'a NameBinding<'a>>,
1454 pub introduced_by_item: bool,
1457 /// The main resolver class.
1459 /// This is the visitor that walks the whole crate.
1460 pub struct Resolver<'a> {
1461 session: &'a Session,
1464 pub definitions: Definitions,
1466 graph_root: Module<'a>,
1468 prelude: Option<Module<'a>>,
1469 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1471 /// n.b. This is used only for better diagnostics, not name resolution itself.
1472 has_self: FxHashSet<DefId>,
1474 /// Names of fields of an item `DefId` accessible with dot syntax.
1475 /// Used for hints during error reporting.
1476 field_names: FxHashMap<DefId, Vec<Name>>,
1478 /// All imports known to succeed or fail.
1479 determined_imports: Vec<&'a ImportDirective<'a>>,
1481 /// All non-determined imports.
1482 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1484 /// The module that represents the current item scope.
1485 current_module: Module<'a>,
1487 /// The current set of local scopes for types and values.
1488 /// FIXME #4948: Reuse ribs to avoid allocation.
1489 ribs: PerNS<Vec<Rib<'a>>>,
1491 /// The current set of local scopes, for labels.
1492 label_ribs: Vec<Rib<'a>>,
1494 /// The trait that the current context can refer to.
1495 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1497 /// The current self type if inside an impl (used for better errors).
1498 current_self_type: Option<Ty>,
1500 /// The current self item if inside an ADT (used for better errors).
1501 current_self_item: Option<NodeId>,
1503 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1504 /// We are resolving a last import segment during import validation.
1505 last_import_segment: bool,
1506 /// This binding should be ignored during in-module resolution, so that we don't get
1507 /// "self-confirming" import resolutions during import validation.
1508 blacklisted_binding: Option<&'a NameBinding<'a>>,
1510 /// The idents for the primitive types.
1511 primitive_type_table: PrimitiveTypeTable,
1514 import_map: ImportMap,
1515 pub freevars: FreevarMap,
1516 freevars_seen: NodeMap<NodeMap<usize>>,
1517 pub export_map: ExportMap,
1518 pub trait_map: TraitMap,
1520 /// A map from nodes to anonymous modules.
1521 /// Anonymous modules are pseudo-modules that are implicitly created around items
1522 /// contained within blocks.
1524 /// For example, if we have this:
1532 /// There will be an anonymous module created around `g` with the ID of the
1533 /// entry block for `f`.
1534 block_map: NodeMap<Module<'a>>,
1535 module_map: FxHashMap<DefId, Module<'a>>,
1536 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1537 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1539 pub make_glob_map: bool,
1540 /// Maps imports to the names of items actually imported (this actually maps
1541 /// all imports, but only glob imports are actually interesting).
1542 pub glob_map: GlobMap,
1544 used_imports: FxHashSet<(NodeId, Namespace)>,
1545 pub maybe_unused_trait_imports: NodeSet,
1546 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1548 /// A list of labels as of yet unused. Labels will be removed from this map when
1549 /// they are used (in a `break` or `continue` statement)
1550 pub unused_labels: FxHashMap<NodeId, Span>,
1552 /// privacy errors are delayed until the end in order to deduplicate them
1553 privacy_errors: Vec<PrivacyError<'a>>,
1554 /// ambiguity errors are delayed for deduplication
1555 ambiguity_errors: Vec<AmbiguityError<'a>>,
1556 /// `use` injections are delayed for better placement and deduplication
1557 use_injections: Vec<UseError<'a>>,
1558 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1559 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1561 arenas: &'a ResolverArenas<'a>,
1562 dummy_binding: &'a NameBinding<'a>,
1564 crate_loader: &'a mut CrateLoader<'a>,
1565 macro_names: FxHashSet<Ident>,
1566 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1567 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1568 pub all_macros: FxHashMap<Name, Def>,
1569 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1570 macro_defs: FxHashMap<Mark, DefId>,
1571 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1573 /// List of crate local macros that we need to warn about as being unused.
1574 /// Right now this only includes macro_rules! macros, and macros 2.0.
1575 unused_macros: FxHashSet<DefId>,
1577 /// Maps the `Mark` of an expansion to its containing module or block.
1578 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1580 /// Avoid duplicated errors for "name already defined".
1581 name_already_seen: FxHashMap<Name, Span>,
1583 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1585 /// This table maps struct IDs into struct constructor IDs,
1586 /// it's not used during normal resolution, only for better error reporting.
1587 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1589 /// Only used for better errors on `fn(): fn()`
1590 current_type_ascription: Vec<Span>,
1592 injected_crate: Option<Module<'a>>,
1595 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1597 pub struct ResolverArenas<'a> {
1598 modules: arena::TypedArena<ModuleData<'a>>,
1599 local_modules: RefCell<Vec<Module<'a>>>,
1600 name_bindings: arena::TypedArena<NameBinding<'a>>,
1601 import_directives: arena::TypedArena<ImportDirective<'a>>,
1602 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1603 invocation_data: arena::TypedArena<InvocationData<'a>>,
1604 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1607 impl<'a> ResolverArenas<'a> {
1608 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1609 let module = self.modules.alloc(module);
1610 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1611 self.local_modules.borrow_mut().push(module);
1615 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1616 self.local_modules.borrow()
1618 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1619 self.name_bindings.alloc(name_binding)
1621 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1622 -> &'a ImportDirective {
1623 self.import_directives.alloc(import_directive)
1625 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1626 self.name_resolutions.alloc(Default::default())
1628 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1629 -> &'a InvocationData<'a> {
1630 self.invocation_data.alloc(expansion_data)
1632 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1633 self.legacy_bindings.alloc(binding)
1637 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1638 fn parent(self, id: DefId) -> Option<DefId> {
1640 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1641 _ => self.cstore.def_key(id).parent,
1642 }.map(|index| DefId { index, ..id })
1646 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1647 /// the resolver is no longer needed as all the relevant information is inline.
1648 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1649 fn resolve_hir_path(
1654 self.resolve_hir_path_cb(path, is_value,
1655 |resolver, span, error| resolve_error(resolver, span, error))
1658 fn resolve_str_path(
1661 crate_root: Option<&str>,
1662 components: &[&str],
1665 let segments = iter::once(keywords::PathRoot.ident())
1667 crate_root.into_iter()
1668 .chain(components.iter().cloned())
1669 .map(Ident::from_str)
1670 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1673 let path = ast::Path {
1678 self.resolve_hir_path(&path, is_value)
1681 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1682 self.def_map.get(&id).cloned()
1685 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1686 self.import_map.get(&id).cloned().unwrap_or_default()
1689 fn definitions(&mut self) -> &mut Definitions {
1690 &mut self.definitions
1694 impl<'a> Resolver<'a> {
1695 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1696 /// isn't something that can be returned because it can't be made to live that long,
1697 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1698 /// just that an error occurred.
1699 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1700 -> Result<hir::Path, ()> {
1702 let mut errored = false;
1704 let path = if path_str.starts_with("::") {
1707 segments: iter::once(keywords::PathRoot.ident())
1709 path_str.split("::").skip(1).map(Ident::from_str)
1711 .map(|i| self.new_ast_path_segment(i))
1719 .map(Ident::from_str)
1720 .map(|i| self.new_ast_path_segment(i))
1724 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1725 if errored || path.def == Def::Err {
1732 /// resolve_hir_path, but takes a callback in case there was an error
1733 fn resolve_hir_path_cb<F>(
1739 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1741 let namespace = if is_value { ValueNS } else { TypeNS };
1742 let span = path.span;
1743 let segments = &path.segments;
1744 let path = Segment::from_path(&path);
1745 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1746 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1747 span, CrateLint::No) {
1748 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1749 module.def().unwrap(),
1750 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1751 path_res.base_def(),
1752 PathResult::NonModule(..) => {
1753 let msg = "type-relative paths are not supported in this context";
1754 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1757 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1758 PathResult::Failed(span, msg, _) => {
1759 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1764 let segments: Vec<_> = segments.iter().map(|seg| {
1765 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1766 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1772 segments: segments.into(),
1776 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1777 let mut seg = ast::PathSegment::from_ident(ident);
1778 seg.id = self.session.next_node_id();
1783 impl<'a> Resolver<'a> {
1784 pub fn new(session: &'a Session,
1788 make_glob_map: MakeGlobMap,
1789 crate_loader: &'a mut CrateLoader<'a>,
1790 arenas: &'a ResolverArenas<'a>)
1792 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1793 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1794 let graph_root = arenas.alloc_module(ModuleData {
1795 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1796 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1798 let mut module_map = FxHashMap::default();
1799 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1801 let mut definitions = Definitions::new();
1802 DefCollector::new(&mut definitions, Mark::root())
1803 .collect_root(crate_name, session.local_crate_disambiguator());
1805 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1806 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1809 if !attr::contains_name(&krate.attrs, "no_core") {
1810 extern_prelude.insert(Ident::from_str("core"), Default::default());
1811 if !attr::contains_name(&krate.attrs, "no_std") {
1812 extern_prelude.insert(Ident::from_str("std"), Default::default());
1813 if session.rust_2018() {
1814 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1819 let mut invocations = FxHashMap::default();
1820 invocations.insert(Mark::root(),
1821 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1823 let mut macro_defs = FxHashMap::default();
1824 macro_defs.insert(Mark::root(), root_def_id);
1833 // The outermost module has def ID 0; this is not reflected in the
1839 has_self: FxHashSet::default(),
1840 field_names: FxHashMap::default(),
1842 determined_imports: Vec::new(),
1843 indeterminate_imports: Vec::new(),
1845 current_module: graph_root,
1847 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1848 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1849 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1851 label_ribs: Vec::new(),
1853 current_trait_ref: None,
1854 current_self_type: None,
1855 current_self_item: None,
1856 last_import_segment: false,
1857 blacklisted_binding: None,
1859 primitive_type_table: PrimitiveTypeTable::new(),
1861 def_map: Default::default(),
1862 import_map: Default::default(),
1863 freevars: Default::default(),
1864 freevars_seen: Default::default(),
1865 export_map: FxHashMap::default(),
1866 trait_map: Default::default(),
1868 block_map: Default::default(),
1869 extern_module_map: FxHashMap::default(),
1870 binding_parent_modules: FxHashMap::default(),
1872 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1873 glob_map: Default::default(),
1875 used_imports: FxHashSet::default(),
1876 maybe_unused_trait_imports: Default::default(),
1877 maybe_unused_extern_crates: Vec::new(),
1879 unused_labels: FxHashMap::default(),
1881 privacy_errors: Vec::new(),
1882 ambiguity_errors: Vec::new(),
1883 use_injections: Vec::new(),
1884 macro_expanded_macro_export_errors: BTreeSet::new(),
1887 dummy_binding: arenas.alloc_name_binding(NameBinding {
1888 kind: NameBindingKind::Def(Def::Err, false),
1890 expansion: Mark::root(),
1892 vis: ty::Visibility::Public,
1896 macro_names: FxHashSet::default(),
1897 builtin_macros: FxHashMap::default(),
1898 macro_use_prelude: FxHashMap::default(),
1899 all_macros: FxHashMap::default(),
1900 macro_map: FxHashMap::default(),
1903 local_macro_def_scopes: FxHashMap::default(),
1904 name_already_seen: FxHashMap::default(),
1905 potentially_unused_imports: Vec::new(),
1906 struct_constructors: Default::default(),
1907 unused_macros: FxHashSet::default(),
1908 current_type_ascription: Vec::new(),
1909 injected_crate: None,
1913 pub fn arenas() -> ResolverArenas<'a> {
1917 /// Runs the function on each namespace.
1918 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1924 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1926 match self.macro_defs.get(&ctxt.outer()) {
1927 Some(&def_id) => return def_id,
1928 None => ctxt.remove_mark(),
1933 /// Entry point to crate resolution.
1934 pub fn resolve_crate(&mut self, krate: &Crate) {
1935 ImportResolver { resolver: self }.finalize_imports();
1936 self.current_module = self.graph_root;
1937 self.finalize_current_module_macro_resolutions();
1939 visit::walk_crate(self, krate);
1941 check_unused::check_crate(self, krate);
1942 self.report_errors(krate);
1943 self.crate_loader.postprocess(krate);
1950 normal_ancestor_id: DefId,
1954 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1955 self.arenas.alloc_module(module)
1958 fn record_use(&mut self, ident: Ident, ns: Namespace,
1959 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1960 if let Some((b2, kind)) = used_binding.ambiguity {
1961 self.ambiguity_errors.push(AmbiguityError {
1962 kind, ident, b1: used_binding, b2,
1963 misc1: AmbiguityErrorMisc::None,
1964 misc2: AmbiguityErrorMisc::None,
1967 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1968 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1969 // but not introduce it, as used if they are accessed from lexical scope.
1970 if is_lexical_scope {
1971 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1972 if let Some(crate_item) = entry.extern_crate_item {
1973 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1980 directive.used.set(true);
1981 self.used_imports.insert((directive.id, ns));
1982 self.add_to_glob_map(directive.id, ident);
1983 self.record_use(ident, ns, binding, false);
1987 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1988 if self.make_glob_map {
1989 self.glob_map.entry(id).or_default().insert(ident.name);
1993 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1994 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1995 /// `ident` in the first scope that defines it (or None if no scopes define it).
1997 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1998 /// the items are defined in the block. For example,
2001 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2004 /// g(); // This resolves to the local variable `g` since it shadows the item.
2008 /// Invariant: This must only be called during main resolution, not during
2009 /// import resolution.
2010 fn resolve_ident_in_lexical_scope(&mut self,
2013 record_used_id: Option<NodeId>,
2015 -> Option<LexicalScopeBinding<'a>> {
2016 assert!(ns == TypeNS || ns == ValueNS);
2017 if ident.name == keywords::Invalid.name() {
2018 return Some(LexicalScopeBinding::Def(Def::Err));
2021 ident.span = if ident.name == keywords::SelfUpper.name() {
2022 // FIXME(jseyfried) improve `Self` hygiene
2023 ident.span.with_ctxt(SyntaxContext::empty())
2028 ident = ident.modern_and_legacy();
2031 // Walk backwards up the ribs in scope.
2032 let record_used = record_used_id.is_some();
2033 let mut module = self.graph_root;
2034 for i in (0 .. self.ribs[ns].len()).rev() {
2035 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2036 // The ident resolves to a type parameter or local variable.
2037 return Some(LexicalScopeBinding::Def(
2038 self.adjust_local_def(ns, i, def, record_used, path_span)
2042 module = match self.ribs[ns][i].kind {
2043 ModuleRibKind(module) => module,
2044 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2045 // If an invocation of this macro created `ident`, give up on `ident`
2046 // and switch to `ident`'s source from the macro definition.
2047 ident.span.remove_mark();
2053 let item = self.resolve_ident_in_module_unadjusted(
2054 ModuleOrUniformRoot::Module(module),
2060 if let Ok(binding) = item {
2061 // The ident resolves to an item.
2062 return Some(LexicalScopeBinding::Item(binding));
2066 ModuleKind::Block(..) => {}, // We can see through blocks
2071 ident.span = ident.span.modern();
2072 let mut poisoned = None;
2074 let opt_module = if let Some(node_id) = record_used_id {
2075 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2076 node_id, &mut poisoned)
2078 self.hygienic_lexical_parent(module, &mut ident.span)
2080 module = unwrap_or!(opt_module, break);
2081 let orig_current_module = self.current_module;
2082 self.current_module = module; // Lexical resolutions can never be a privacy error.
2083 let result = self.resolve_ident_in_module_unadjusted(
2084 ModuleOrUniformRoot::Module(module),
2090 self.current_module = orig_current_module;
2094 if let Some(node_id) = poisoned {
2095 self.session.buffer_lint_with_diagnostic(
2096 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2097 node_id, ident.span,
2098 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2099 lint::builtin::BuiltinLintDiagnostics::
2100 ProcMacroDeriveResolutionFallback(ident.span),
2103 return Some(LexicalScopeBinding::Item(binding))
2105 Err(Determined) => continue,
2106 Err(Undetermined) =>
2107 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2111 if !module.no_implicit_prelude {
2113 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2114 return Some(LexicalScopeBinding::Item(binding));
2117 if ns == TypeNS && is_known_tool(ident.name) {
2118 let binding = (Def::ToolMod, ty::Visibility::Public,
2119 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2120 return Some(LexicalScopeBinding::Item(binding));
2122 if let Some(prelude) = self.prelude {
2123 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2124 ModuleOrUniformRoot::Module(prelude),
2130 return Some(LexicalScopeBinding::Item(binding));
2138 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2139 -> Option<Module<'a>> {
2140 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2141 return Some(self.macro_def_scope(span.remove_mark()));
2144 if let ModuleKind::Block(..) = module.kind {
2145 return Some(module.parent.unwrap());
2151 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2152 span: &mut Span, node_id: NodeId,
2153 poisoned: &mut Option<NodeId>)
2154 -> Option<Module<'a>> {
2155 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2159 // We need to support the next case under a deprecation warning
2162 // ---- begin: this comes from a proc macro derive
2163 // mod implementation_details {
2164 // // Note that `MyStruct` is not in scope here.
2165 // impl SomeTrait for MyStruct { ... }
2169 // So we have to fall back to the module's parent during lexical resolution in this case.
2170 if let Some(parent) = module.parent {
2171 // Inner module is inside the macro, parent module is outside of the macro.
2172 if module.expansion != parent.expansion &&
2173 module.expansion.is_descendant_of(parent.expansion) {
2174 // The macro is a proc macro derive
2175 if module.expansion.looks_like_proc_macro_derive() {
2176 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2177 *poisoned = Some(node_id);
2178 return module.parent;
2187 fn resolve_ident_in_module(
2189 module: ModuleOrUniformRoot<'a>,
2192 parent_scope: Option<&ParentScope<'a>>,
2195 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2196 self.resolve_ident_in_module_ext(
2197 module, ident, ns, parent_scope, record_used, path_span
2198 ).map_err(|(determinacy, _)| determinacy)
2201 fn resolve_ident_in_module_ext(
2203 module: ModuleOrUniformRoot<'a>,
2206 parent_scope: Option<&ParentScope<'a>>,
2209 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2210 let orig_current_module = self.current_module;
2212 ModuleOrUniformRoot::Module(module) => {
2213 ident.span = ident.span.modern();
2214 if let Some(def) = ident.span.adjust(module.expansion) {
2215 self.current_module = self.macro_def_scope(def);
2218 ModuleOrUniformRoot::ExternPrelude => {
2219 ident.span = ident.span.modern();
2220 ident.span.adjust(Mark::root());
2222 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2223 ModuleOrUniformRoot::CurrentScope => {
2227 let result = self.resolve_ident_in_module_unadjusted_ext(
2228 module, ident, ns, parent_scope, false, record_used, path_span,
2230 self.current_module = orig_current_module;
2234 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2235 let mut ctxt = ident.span.ctxt();
2236 let mark = if ident.name == keywords::DollarCrate.name() {
2237 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2238 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2239 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2240 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2241 // definitions actually produced by `macro` and `macro` definitions produced by
2242 // `macro_rules!`, but at least such configurations are not stable yet.
2243 ctxt = ctxt.modern_and_legacy();
2244 let mut iter = ctxt.marks().into_iter().rev().peekable();
2245 let mut result = None;
2246 // Find the last modern mark from the end if it exists.
2247 while let Some(&(mark, transparency)) = iter.peek() {
2248 if transparency == Transparency::Opaque {
2249 result = Some(mark);
2255 // Then find the last legacy mark from the end if it exists.
2256 for (mark, transparency) in iter {
2257 if transparency == Transparency::SemiTransparent {
2258 result = Some(mark);
2265 ctxt = ctxt.modern();
2266 ctxt.adjust(Mark::root())
2268 let module = match mark {
2269 Some(def) => self.macro_def_scope(def),
2270 None => return self.graph_root,
2272 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2275 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2276 let mut module = self.get_module(module.normal_ancestor_id);
2277 while module.span.ctxt().modern() != *ctxt {
2278 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2279 module = self.get_module(parent.normal_ancestor_id);
2286 // We maintain a list of value ribs and type ribs.
2288 // Simultaneously, we keep track of the current position in the module
2289 // graph in the `current_module` pointer. When we go to resolve a name in
2290 // the value or type namespaces, we first look through all the ribs and
2291 // then query the module graph. When we resolve a name in the module
2292 // namespace, we can skip all the ribs (since nested modules are not
2293 // allowed within blocks in Rust) and jump straight to the current module
2296 // Named implementations are handled separately. When we find a method
2297 // call, we consult the module node to find all of the implementations in
2298 // scope. This information is lazily cached in the module node. We then
2299 // generate a fake "implementation scope" containing all the
2300 // implementations thus found, for compatibility with old resolve pass.
2302 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2303 where F: FnOnce(&mut Resolver) -> T
2305 let id = self.definitions.local_def_id(id);
2306 let module = self.module_map.get(&id).cloned(); // clones a reference
2307 if let Some(module) = module {
2308 // Move down in the graph.
2309 let orig_module = replace(&mut self.current_module, module);
2310 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2311 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2313 self.finalize_current_module_macro_resolutions();
2316 self.current_module = orig_module;
2317 self.ribs[ValueNS].pop();
2318 self.ribs[TypeNS].pop();
2325 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2326 /// is returned by the given predicate function
2328 /// Stops after meeting a closure.
2329 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2330 where P: Fn(&Rib, Ident) -> Option<R>
2332 for rib in self.label_ribs.iter().rev() {
2335 // If an invocation of this macro created `ident`, give up on `ident`
2336 // and switch to `ident`'s source from the macro definition.
2337 MacroDefinition(def) => {
2338 if def == self.macro_def(ident.span.ctxt()) {
2339 ident.span.remove_mark();
2343 // Do not resolve labels across function boundary
2347 let r = pred(rib, ident);
2355 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2356 self.with_current_self_item(item, |this| {
2357 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2358 let item_def_id = this.definitions.local_def_id(item.id);
2359 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2360 visit::walk_item(this, item);
2366 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2367 let segments = &use_tree.prefix.segments;
2368 if !segments.is_empty() {
2369 let ident = segments[0].ident;
2370 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2374 let nss = match use_tree.kind {
2375 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2379 if let Some(LexicalScopeBinding::Def(..)) =
2380 self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2381 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2382 self.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2385 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2386 for (use_tree, _) in use_trees {
2387 self.future_proof_import(use_tree);
2392 fn resolve_item(&mut self, item: &Item) {
2393 let name = item.ident.name;
2394 debug!("(resolving item) resolving {}", name);
2397 ItemKind::Ty(_, ref generics) |
2398 ItemKind::Fn(_, _, ref generics, _) |
2399 ItemKind::Existential(_, ref generics) => {
2400 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2401 |this| visit::walk_item(this, item));
2404 ItemKind::Enum(_, ref generics) |
2405 ItemKind::Struct(_, ref generics) |
2406 ItemKind::Union(_, ref generics) => {
2407 self.resolve_adt(item, generics);
2410 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2411 self.resolve_implementation(generics,
2417 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2418 // Create a new rib for the trait-wide type parameters.
2419 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2420 let local_def_id = this.definitions.local_def_id(item.id);
2421 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2422 this.visit_generics(generics);
2423 walk_list!(this, visit_param_bound, bounds);
2425 for trait_item in trait_items {
2426 let type_parameters = HasTypeParameters(&trait_item.generics,
2427 TraitOrImplItemRibKind);
2428 this.with_type_parameter_rib(type_parameters, |this| {
2429 match trait_item.node {
2430 TraitItemKind::Const(ref ty, ref default) => {
2433 // Only impose the restrictions of
2434 // ConstRibKind for an actual constant
2435 // expression in a provided default.
2436 if let Some(ref expr) = *default{
2437 this.with_constant_rib(|this| {
2438 this.visit_expr(expr);
2442 TraitItemKind::Method(_, _) => {
2443 visit::walk_trait_item(this, trait_item)
2445 TraitItemKind::Type(..) => {
2446 visit::walk_trait_item(this, trait_item)
2448 TraitItemKind::Macro(_) => {
2449 panic!("unexpanded macro in resolve!")
2458 ItemKind::TraitAlias(ref generics, ref bounds) => {
2459 // Create a new rib for the trait-wide type parameters.
2460 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2461 let local_def_id = this.definitions.local_def_id(item.id);
2462 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2463 this.visit_generics(generics);
2464 walk_list!(this, visit_param_bound, bounds);
2469 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2470 self.with_scope(item.id, |this| {
2471 visit::walk_item(this, item);
2475 ItemKind::Static(ref ty, _, ref expr) |
2476 ItemKind::Const(ref ty, ref expr) => {
2477 self.with_item_rib(|this| {
2479 this.with_constant_rib(|this| {
2480 this.visit_expr(expr);
2485 ItemKind::Use(ref use_tree) => {
2486 self.future_proof_import(use_tree);
2489 ItemKind::ExternCrate(..) |
2490 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2491 // do nothing, these are just around to be encoded
2494 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2498 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2499 where F: FnOnce(&mut Resolver)
2501 match type_parameters {
2502 HasTypeParameters(generics, rib_kind) => {
2503 let mut function_type_rib = Rib::new(rib_kind);
2504 let mut seen_bindings = FxHashMap::default();
2505 for param in &generics.params {
2507 GenericParamKind::Lifetime { .. } => {}
2508 GenericParamKind::Type { .. } => {
2509 let ident = param.ident.modern();
2510 debug!("with_type_parameter_rib: {}", param.id);
2512 if seen_bindings.contains_key(&ident) {
2513 let span = seen_bindings.get(&ident).unwrap();
2514 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2518 resolve_error(self, param.ident.span, err);
2520 seen_bindings.entry(ident).or_insert(param.ident.span);
2522 // Plain insert (no renaming).
2523 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2524 function_type_rib.bindings.insert(ident, def);
2525 self.record_def(param.id, PathResolution::new(def));
2529 self.ribs[TypeNS].push(function_type_rib);
2532 NoTypeParameters => {
2539 if let HasTypeParameters(..) = type_parameters {
2540 self.ribs[TypeNS].pop();
2544 fn with_label_rib<F>(&mut self, f: F)
2545 where F: FnOnce(&mut Resolver)
2547 self.label_ribs.push(Rib::new(NormalRibKind));
2549 self.label_ribs.pop();
2552 fn with_item_rib<F>(&mut self, f: F)
2553 where F: FnOnce(&mut Resolver)
2555 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2556 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2558 self.ribs[TypeNS].pop();
2559 self.ribs[ValueNS].pop();
2562 fn with_constant_rib<F>(&mut self, f: F)
2563 where F: FnOnce(&mut Resolver)
2565 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2566 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2568 self.label_ribs.pop();
2569 self.ribs[ValueNS].pop();
2572 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2573 where F: FnOnce(&mut Resolver) -> T
2575 // Handle nested impls (inside fn bodies)
2576 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2577 let result = f(self);
2578 self.current_self_type = previous_value;
2582 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2583 where F: FnOnce(&mut Resolver) -> T
2585 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2586 let result = f(self);
2587 self.current_self_item = previous_value;
2591 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2592 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2593 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2595 let mut new_val = None;
2596 let mut new_id = None;
2597 if let Some(trait_ref) = opt_trait_ref {
2598 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2599 let def = self.smart_resolve_path_fragment(
2603 trait_ref.path.span,
2604 PathSource::Trait(AliasPossibility::No),
2605 CrateLint::SimplePath(trait_ref.ref_id),
2607 if def != Def::Err {
2608 new_id = Some(def.def_id());
2609 let span = trait_ref.path.span;
2610 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2611 self.resolve_path_without_parent_scope(
2616 CrateLint::SimplePath(trait_ref.ref_id),
2619 new_val = Some((module, trait_ref.clone()));
2623 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2624 let result = f(self, new_id);
2625 self.current_trait_ref = original_trait_ref;
2629 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2630 where F: FnOnce(&mut Resolver)
2632 let mut self_type_rib = Rib::new(NormalRibKind);
2634 // plain insert (no renaming, types are not currently hygienic....)
2635 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2636 self.ribs[TypeNS].push(self_type_rib);
2638 self.ribs[TypeNS].pop();
2641 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2642 where F: FnOnce(&mut Resolver)
2644 let self_def = Def::SelfCtor(impl_id);
2645 let mut self_type_rib = Rib::new(NormalRibKind);
2646 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2647 self.ribs[ValueNS].push(self_type_rib);
2649 self.ribs[ValueNS].pop();
2652 fn resolve_implementation(&mut self,
2653 generics: &Generics,
2654 opt_trait_reference: &Option<TraitRef>,
2657 impl_items: &[ImplItem]) {
2658 // If applicable, create a rib for the type parameters.
2659 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2660 // Dummy self type for better errors if `Self` is used in the trait path.
2661 this.with_self_rib(Def::SelfTy(None, None), |this| {
2662 // Resolve the trait reference, if necessary.
2663 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2664 let item_def_id = this.definitions.local_def_id(item_id);
2665 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2666 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2667 // Resolve type arguments in the trait path.
2668 visit::walk_trait_ref(this, trait_ref);
2670 // Resolve the self type.
2671 this.visit_ty(self_type);
2672 // Resolve the type parameters.
2673 this.visit_generics(generics);
2674 // Resolve the items within the impl.
2675 this.with_current_self_type(self_type, |this| {
2676 this.with_self_struct_ctor_rib(item_def_id, |this| {
2677 for impl_item in impl_items {
2678 this.resolve_visibility(&impl_item.vis);
2680 // We also need a new scope for the impl item type parameters.
2681 let type_parameters = HasTypeParameters(&impl_item.generics,
2682 TraitOrImplItemRibKind);
2683 this.with_type_parameter_rib(type_parameters, |this| {
2684 use self::ResolutionError::*;
2685 match impl_item.node {
2686 ImplItemKind::Const(..) => {
2687 // If this is a trait impl, ensure the const
2689 this.check_trait_item(impl_item.ident,
2692 |n, s| ConstNotMemberOfTrait(n, s));
2693 this.with_constant_rib(|this|
2694 visit::walk_impl_item(this, impl_item)
2697 ImplItemKind::Method(..) => {
2698 // If this is a trait impl, ensure the method
2700 this.check_trait_item(impl_item.ident,
2703 |n, s| MethodNotMemberOfTrait(n, s));
2705 visit::walk_impl_item(this, impl_item);
2707 ImplItemKind::Type(ref ty) => {
2708 // If this is a trait impl, ensure the type
2710 this.check_trait_item(impl_item.ident,
2713 |n, s| TypeNotMemberOfTrait(n, s));
2717 ImplItemKind::Existential(ref bounds) => {
2718 // If this is a trait impl, ensure the type
2720 this.check_trait_item(impl_item.ident,
2723 |n, s| TypeNotMemberOfTrait(n, s));
2725 for bound in bounds {
2726 this.visit_param_bound(bound);
2729 ImplItemKind::Macro(_) =>
2730 panic!("unexpanded macro in resolve!"),
2742 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2743 where F: FnOnce(Name, &str) -> ResolutionError
2745 // If there is a TraitRef in scope for an impl, then the method must be in the
2747 if let Some((module, _)) = self.current_trait_ref {
2748 if self.resolve_ident_in_module(
2749 ModuleOrUniformRoot::Module(module),
2756 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2757 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2762 fn resolve_local(&mut self, local: &Local) {
2763 // Resolve the type.
2764 walk_list!(self, visit_ty, &local.ty);
2766 // Resolve the initializer.
2767 walk_list!(self, visit_expr, &local.init);
2769 // Resolve the pattern.
2770 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2773 // build a map from pattern identifiers to binding-info's.
2774 // this is done hygienically. This could arise for a macro
2775 // that expands into an or-pattern where one 'x' was from the
2776 // user and one 'x' came from the macro.
2777 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2778 let mut binding_map = FxHashMap::default();
2780 pat.walk(&mut |pat| {
2781 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2782 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2783 Some(Def::Local(..)) => true,
2786 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2787 binding_map.insert(ident, binding_info);
2796 // check that all of the arms in an or-pattern have exactly the
2797 // same set of bindings, with the same binding modes for each.
2798 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2799 if pats.is_empty() {
2803 let mut missing_vars = FxHashMap::default();
2804 let mut inconsistent_vars = FxHashMap::default();
2805 for (i, p) in pats.iter().enumerate() {
2806 let map_i = self.binding_mode_map(&p);
2808 for (j, q) in pats.iter().enumerate() {
2813 let map_j = self.binding_mode_map(&q);
2814 for (&key, &binding_i) in &map_i {
2815 if map_j.is_empty() { // Account for missing bindings when
2816 let binding_error = missing_vars // map_j has none.
2818 .or_insert(BindingError {
2820 origin: BTreeSet::new(),
2821 target: BTreeSet::new(),
2823 binding_error.origin.insert(binding_i.span);
2824 binding_error.target.insert(q.span);
2826 for (&key_j, &binding_j) in &map_j {
2827 match map_i.get(&key_j) {
2828 None => { // missing binding
2829 let binding_error = missing_vars
2831 .or_insert(BindingError {
2833 origin: BTreeSet::new(),
2834 target: BTreeSet::new(),
2836 binding_error.origin.insert(binding_j.span);
2837 binding_error.target.insert(p.span);
2839 Some(binding_i) => { // check consistent binding
2840 if binding_i.binding_mode != binding_j.binding_mode {
2843 .or_insert((binding_j.span, binding_i.span));
2851 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2852 missing_vars.sort();
2853 for (_, v) in missing_vars {
2855 *v.origin.iter().next().unwrap(),
2856 ResolutionError::VariableNotBoundInPattern(v));
2858 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2859 inconsistent_vars.sort();
2860 for (name, v) in inconsistent_vars {
2861 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2865 fn resolve_arm(&mut self, arm: &Arm) {
2866 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2868 let mut bindings_list = FxHashMap::default();
2869 for pattern in &arm.pats {
2870 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2873 // This has to happen *after* we determine which pat_idents are variants.
2874 self.check_consistent_bindings(&arm.pats);
2876 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2877 self.visit_expr(expr)
2879 self.visit_expr(&arm.body);
2881 self.ribs[ValueNS].pop();
2884 fn resolve_block(&mut self, block: &Block) {
2885 debug!("(resolving block) entering block");
2886 // Move down in the graph, if there's an anonymous module rooted here.
2887 let orig_module = self.current_module;
2888 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2890 let mut num_macro_definition_ribs = 0;
2891 if let Some(anonymous_module) = anonymous_module {
2892 debug!("(resolving block) found anonymous module, moving down");
2893 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2894 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2895 self.current_module = anonymous_module;
2896 self.finalize_current_module_macro_resolutions();
2898 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2901 // Descend into the block.
2902 for stmt in &block.stmts {
2903 if let ast::StmtKind::Item(ref item) = stmt.node {
2904 if let ast::ItemKind::MacroDef(..) = item.node {
2905 num_macro_definition_ribs += 1;
2906 let def = self.definitions.local_def_id(item.id);
2907 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2908 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2912 self.visit_stmt(stmt);
2916 self.current_module = orig_module;
2917 for _ in 0 .. num_macro_definition_ribs {
2918 self.ribs[ValueNS].pop();
2919 self.label_ribs.pop();
2921 self.ribs[ValueNS].pop();
2922 if anonymous_module.is_some() {
2923 self.ribs[TypeNS].pop();
2925 debug!("(resolving block) leaving block");
2928 fn fresh_binding(&mut self,
2931 outer_pat_id: NodeId,
2932 pat_src: PatternSource,
2933 bindings: &mut FxHashMap<Ident, NodeId>)
2935 // Add the binding to the local ribs, if it
2936 // doesn't already exist in the bindings map. (We
2937 // must not add it if it's in the bindings map
2938 // because that breaks the assumptions later
2939 // passes make about or-patterns.)
2940 let ident = ident.modern_and_legacy();
2941 let mut def = Def::Local(pat_id);
2942 match bindings.get(&ident).cloned() {
2943 Some(id) if id == outer_pat_id => {
2944 // `Variant(a, a)`, error
2948 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2952 Some(..) if pat_src == PatternSource::FnParam => {
2953 // `fn f(a: u8, a: u8)`, error
2957 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2961 Some(..) if pat_src == PatternSource::Match ||
2962 pat_src == PatternSource::IfLet ||
2963 pat_src == PatternSource::WhileLet => {
2964 // `Variant1(a) | Variant2(a)`, ok
2965 // Reuse definition from the first `a`.
2966 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2969 span_bug!(ident.span, "two bindings with the same name from \
2970 unexpected pattern source {:?}", pat_src);
2973 // A completely fresh binding, add to the lists if it's valid.
2974 if ident.name != keywords::Invalid.name() {
2975 bindings.insert(ident, outer_pat_id);
2976 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2981 PathResolution::new(def)
2984 fn resolve_pattern(&mut self,
2986 pat_src: PatternSource,
2987 // Maps idents to the node ID for the
2988 // outermost pattern that binds them.
2989 bindings: &mut FxHashMap<Ident, NodeId>) {
2990 // Visit all direct subpatterns of this pattern.
2991 let outer_pat_id = pat.id;
2992 pat.walk(&mut |pat| {
2993 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
2995 PatKind::Ident(bmode, ident, ref opt_pat) => {
2996 // First try to resolve the identifier as some existing
2997 // entity, then fall back to a fresh binding.
2998 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3000 .and_then(LexicalScopeBinding::item);
3001 let resolution = binding.map(NameBinding::def).and_then(|def| {
3002 let is_syntactic_ambiguity = opt_pat.is_none() &&
3003 bmode == BindingMode::ByValue(Mutability::Immutable);
3005 Def::StructCtor(_, CtorKind::Const) |
3006 Def::VariantCtor(_, CtorKind::Const) |
3007 Def::Const(..) if is_syntactic_ambiguity => {
3008 // Disambiguate in favor of a unit struct/variant
3009 // or constant pattern.
3010 self.record_use(ident, ValueNS, binding.unwrap(), false);
3011 Some(PathResolution::new(def))
3013 Def::StructCtor(..) | Def::VariantCtor(..) |
3014 Def::Const(..) | Def::Static(..) => {
3015 // This is unambiguously a fresh binding, either syntactically
3016 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3017 // to something unusable as a pattern (e.g., constructor function),
3018 // but we still conservatively report an error, see
3019 // issues/33118#issuecomment-233962221 for one reason why.
3023 ResolutionError::BindingShadowsSomethingUnacceptable(
3024 pat_src.descr(), ident.name, binding.unwrap())
3028 Def::Fn(..) | Def::Err => {
3029 // These entities are explicitly allowed
3030 // to be shadowed by fresh bindings.
3034 span_bug!(ident.span, "unexpected definition for an \
3035 identifier in pattern: {:?}", def);
3038 }).unwrap_or_else(|| {
3039 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3042 self.record_def(pat.id, resolution);
3045 PatKind::TupleStruct(ref path, ..) => {
3046 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3049 PatKind::Path(ref qself, ref path) => {
3050 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3053 PatKind::Struct(ref path, ..) => {
3054 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3062 visit::walk_pat(self, pat);
3065 // High-level and context dependent path resolution routine.
3066 // Resolves the path and records the resolution into definition map.
3067 // If resolution fails tries several techniques to find likely
3068 // resolution candidates, suggest imports or other help, and report
3069 // errors in user friendly way.
3070 fn smart_resolve_path(&mut self,
3072 qself: Option<&QSelf>,
3076 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3079 /// A variant of `smart_resolve_path` where you also specify extra
3080 /// information about where the path came from; this extra info is
3081 /// sometimes needed for the lint that recommends rewriting
3082 /// absolute paths to `crate`, so that it knows how to frame the
3083 /// suggestion. If you are just resolving a path like `foo::bar`
3084 /// that appears...somewhere, though, then you just want
3085 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3086 /// already provides.
3087 fn smart_resolve_path_with_crate_lint(
3090 qself: Option<&QSelf>,
3093 crate_lint: CrateLint
3094 ) -> PathResolution {
3095 self.smart_resolve_path_fragment(
3098 &Segment::from_path(path),
3105 fn smart_resolve_path_fragment(&mut self,
3107 qself: Option<&QSelf>,
3111 crate_lint: CrateLint)
3113 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3114 let ns = source.namespace();
3115 let is_expected = &|def| source.is_expected(def);
3116 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3118 // Base error is amended with one short label and possibly some longer helps/notes.
3119 let report_errors = |this: &mut Self, def: Option<Def>| {
3120 // Make the base error.
3121 let expected = source.descr_expected();
3122 let path_str = Segment::names_to_string(path);
3123 let item_str = path.last().unwrap().ident;
3124 let code = source.error_code(def.is_some());
3125 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3126 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3127 format!("not a {}", expected),
3130 let item_span = path.last().unwrap().ident.span;
3131 let (mod_prefix, mod_str) = if path.len() == 1 {
3132 (String::new(), "this scope".to_string())
3133 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3134 (String::new(), "the crate root".to_string())
3136 let mod_path = &path[..path.len() - 1];
3137 let mod_prefix = match this.resolve_path_without_parent_scope(
3138 mod_path, Some(TypeNS), false, span, CrateLint::No
3140 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3143 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3144 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3146 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3147 format!("not found in {}", mod_str),
3151 let code = DiagnosticId::Error(code.into());
3152 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3154 // Emit help message for fake-self from other languages like `this`(javascript)
3155 if ["this", "my"].contains(&&*item_str.as_str())
3156 && this.self_value_is_available(path[0].ident.span, span) {
3157 err.span_suggestion_with_applicability(
3161 Applicability::MaybeIncorrect,
3165 // Emit special messages for unresolved `Self` and `self`.
3166 if is_self_type(path, ns) {
3167 __diagnostic_used!(E0411);
3168 err.code(DiagnosticId::Error("E0411".into()));
3169 err.span_label(span, format!("`Self` is only available in impls, traits, \
3170 and type definitions"));
3171 return (err, Vec::new());
3173 if is_self_value(path, ns) {
3174 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3176 __diagnostic_used!(E0424);
3177 err.code(DiagnosticId::Error("E0424".into()));
3178 err.span_label(span, match source {
3179 PathSource::Pat => {
3180 format!("`self` value is a keyword \
3181 and may not be bound to \
3182 variables or shadowed")
3185 format!("`self` value is a keyword \
3186 only available in methods \
3187 with `self` parameter")
3190 return (err, Vec::new());
3193 // Try to lookup the name in more relaxed fashion for better error reporting.
3194 let ident = path.last().unwrap().ident;
3195 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3196 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3197 let enum_candidates =
3198 this.lookup_import_candidates(ident, ns, is_enum_variant);
3199 let mut enum_candidates = enum_candidates.iter()
3201 import_candidate_to_enum_paths(&suggestion)
3202 }).collect::<Vec<_>>();
3203 enum_candidates.sort();
3205 if !enum_candidates.is_empty() {
3206 // contextualize for E0412 "cannot find type", but don't belabor the point
3207 // (that it's a variant) for E0573 "expected type, found variant"
3208 let preamble = if def.is_none() {
3209 let others = match enum_candidates.len() {
3211 2 => " and 1 other".to_owned(),
3212 n => format!(" and {} others", n)
3214 format!("there is an enum variant `{}`{}; ",
3215 enum_candidates[0].0, others)
3219 let msg = format!("{}try using the variant's enum", preamble);
3221 err.span_suggestions_with_applicability(
3224 enum_candidates.into_iter()
3225 .map(|(_variant_path, enum_ty_path)| enum_ty_path)
3226 // variants reëxported in prelude doesn't mean `prelude::v1` is the
3227 // type name! FIXME: is there a more principled way to do this that
3228 // would work for other reëxports?
3229 .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
3230 // also say `Option` rather than `std::prelude::v1::Option`
3231 .map(|enum_ty_path| {
3232 // FIXME #56861: DRYer prelude filtering
3233 enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
3235 Applicability::MachineApplicable,
3239 if path.len() == 1 && this.self_type_is_available(span) {
3240 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3241 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3243 AssocSuggestion::Field => {
3244 err.span_suggestion_with_applicability(
3247 format!("self.{}", path_str),
3248 Applicability::MachineApplicable,
3250 if !self_is_available {
3251 err.span_label(span, format!("`self` value is a keyword \
3253 methods with `self` parameter"));
3256 AssocSuggestion::MethodWithSelf if self_is_available => {
3257 err.span_suggestion_with_applicability(
3260 format!("self.{}", path_str),
3261 Applicability::MachineApplicable,
3264 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3265 err.span_suggestion_with_applicability(
3268 format!("Self::{}", path_str),
3269 Applicability::MachineApplicable,
3273 return (err, candidates);
3277 let mut levenshtein_worked = false;
3279 // Try Levenshtein algorithm.
3280 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3281 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3282 levenshtein_worked = true;
3285 // Try context dependent help if relaxed lookup didn't work.
3286 if let Some(def) = def {
3287 match (def, source) {
3288 (Def::Macro(..), _) => {
3289 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3290 return (err, candidates);
3292 (Def::TyAlias(..), PathSource::Trait(_)) => {
3293 err.span_label(span, "type aliases cannot be used as traits");
3294 if nightly_options::is_nightly_build() {
3295 err.note("did you mean to use a trait alias?");
3297 return (err, candidates);
3299 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3300 ExprKind::Field(_, ident) => {
3301 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3303 return (err, candidates);
3305 ExprKind::MethodCall(ref segment, ..) => {
3306 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3307 path_str, segment.ident));
3308 return (err, candidates);
3312 (Def::Enum(..), PathSource::TupleStruct)
3313 | (Def::Enum(..), PathSource::Expr(..)) => {
3314 if let Some(variants) = this.collect_enum_variants(def) {
3315 err.note(&format!("did you mean to use one \
3316 of the following variants?\n{}",
3318 .map(|suggestion| path_names_to_string(suggestion))
3319 .map(|suggestion| format!("- `{}`", suggestion))
3320 .collect::<Vec<_>>()
3324 err.note("did you mean to use one of the enum's variants?");
3326 return (err, candidates);
3328 (Def::Struct(def_id), _) if ns == ValueNS => {
3329 if let Some((ctor_def, ctor_vis))
3330 = this.struct_constructors.get(&def_id).cloned() {
3331 let accessible_ctor = this.is_accessible(ctor_vis);
3332 if is_expected(ctor_def) && !accessible_ctor {
3333 err.span_label(span, format!("constructor is not visible \
3334 here due to private fields"));
3337 // HACK(estebank): find a better way to figure out that this was a
3338 // parser issue where a struct literal is being used on an expression
3339 // where a brace being opened means a block is being started. Look
3340 // ahead for the next text to see if `span` is followed by a `{`.
3341 let sm = this.session.source_map();
3344 sp = sm.next_point(sp);
3345 match sm.span_to_snippet(sp) {
3346 Ok(ref snippet) => {
3347 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3354 let followed_by_brace = match sm.span_to_snippet(sp) {
3355 Ok(ref snippet) if snippet == "{" => true,
3359 PathSource::Expr(Some(parent)) => {
3361 ExprKind::MethodCall(ref path_assignment, _) => {
3362 err.span_suggestion_with_applicability(
3363 sm.start_point(parent.span)
3364 .to(path_assignment.ident.span),
3365 "use `::` to access an associated function",
3368 path_assignment.ident),
3369 Applicability::MaybeIncorrect
3371 return (err, candidates);
3376 format!("did you mean `{} {{ /* fields */ }}`?",
3379 return (err, candidates);
3383 PathSource::Expr(None) if followed_by_brace == true => {
3386 format!("did you mean `({} {{ /* fields */ }})`?",
3389 return (err, candidates);
3394 format!("did you mean `{} {{ /* fields */ }}`?",
3397 return (err, candidates);
3401 return (err, candidates);
3403 (Def::Union(..), _) |
3404 (Def::Variant(..), _) |
3405 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3406 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3408 return (err, candidates);
3410 (Def::SelfTy(..), _) if ns == ValueNS => {
3411 err.span_label(span, fallback_label);
3412 err.note("can't use `Self` as a constructor, you must use the \
3413 implemented struct");
3414 return (err, candidates);
3416 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3417 err.note("can't use a type alias as a constructor");
3418 return (err, candidates);
3425 if !levenshtein_worked {
3426 err.span_label(base_span, fallback_label);
3427 this.type_ascription_suggestion(&mut err, base_span);
3431 let report_errors = |this: &mut Self, def: Option<Def>| {
3432 let (err, candidates) = report_errors(this, def);
3433 let def_id = this.current_module.normal_ancestor_id;
3434 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3435 let better = def.is_some();
3436 this.use_injections.push(UseError { err, candidates, node_id, better });
3437 err_path_resolution()
3440 let resolution = match self.resolve_qpath_anywhere(
3446 source.defer_to_typeck(),
3447 source.global_by_default(),
3450 Some(resolution) if resolution.unresolved_segments() == 0 => {
3451 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3454 // Add a temporary hack to smooth the transition to new struct ctor
3455 // visibility rules. See #38932 for more details.
3457 if let Def::Struct(def_id) = resolution.base_def() {
3458 if let Some((ctor_def, ctor_vis))
3459 = self.struct_constructors.get(&def_id).cloned() {
3460 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3461 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3462 self.session.buffer_lint(lint, id, span,
3463 "private struct constructors are not usable through \
3464 re-exports in outer modules",
3466 res = Some(PathResolution::new(ctor_def));
3471 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3474 Some(resolution) if source.defer_to_typeck() => {
3475 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3476 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3477 // it needs to be added to the trait map.
3479 let item_name = path.last().unwrap().ident;
3480 let traits = self.get_traits_containing_item(item_name, ns);
3481 self.trait_map.insert(id, traits);
3485 _ => report_errors(self, None)
3488 if let PathSource::TraitItem(..) = source {} else {
3489 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3490 self.record_def(id, resolution);
3495 fn type_ascription_suggestion(&self,
3496 err: &mut DiagnosticBuilder,
3498 debug!("type_ascription_suggetion {:?}", base_span);
3499 let cm = self.session.source_map();
3500 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3501 if let Some(sp) = self.current_type_ascription.last() {
3503 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3504 sp = cm.next_point(sp);
3505 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3506 debug!("snippet {:?}", snippet);
3507 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3508 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3509 debug!("{:?} {:?}", line_sp, line_base_sp);
3511 err.span_label(base_span,
3512 "expecting a type here because of type ascription");
3513 if line_sp != line_base_sp {
3514 err.span_suggestion_short_with_applicability(
3516 "did you mean to use `;` here instead?",
3518 Applicability::MaybeIncorrect,
3522 } else if !snippet.trim().is_empty() {
3523 debug!("tried to find type ascription `:` token, couldn't find it");
3533 fn self_type_is_available(&mut self, span: Span) -> bool {
3534 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3535 TypeNS, None, span);
3536 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3539 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3540 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3541 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3542 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3545 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3546 fn resolve_qpath_anywhere(&mut self,
3548 qself: Option<&QSelf>,
3550 primary_ns: Namespace,
3552 defer_to_typeck: bool,
3553 global_by_default: bool,
3554 crate_lint: CrateLint)
3555 -> Option<PathResolution> {
3556 let mut fin_res = None;
3557 // FIXME: can't resolve paths in macro namespace yet, macros are
3558 // processed by the little special hack below.
3559 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3560 if i == 0 || ns != primary_ns {
3561 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3562 // If defer_to_typeck, then resolution > no resolution,
3563 // otherwise full resolution > partial resolution > no resolution.
3564 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3566 res => if fin_res.is_none() { fin_res = res },
3570 if primary_ns != MacroNS &&
3571 (self.macro_names.contains(&path[0].ident.modern()) ||
3572 self.builtin_macros.get(&path[0].ident.name).cloned()
3573 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3574 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3575 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3576 // Return some dummy definition, it's enough for error reporting.
3578 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3584 /// Handles paths that may refer to associated items.
3585 fn resolve_qpath(&mut self,
3587 qself: Option<&QSelf>,
3591 global_by_default: bool,
3592 crate_lint: CrateLint)
3593 -> Option<PathResolution> {
3595 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3596 ns={:?}, span={:?}, global_by_default={:?})",
3605 if let Some(qself) = qself {
3606 if qself.position == 0 {
3607 // This is a case like `<T>::B`, where there is no
3608 // trait to resolve. In that case, we leave the `B`
3609 // segment to be resolved by type-check.
3610 return Some(PathResolution::with_unresolved_segments(
3611 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3615 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3617 // Currently, `path` names the full item (`A::B::C`, in
3618 // our example). so we extract the prefix of that that is
3619 // the trait (the slice upto and including
3620 // `qself.position`). And then we recursively resolve that,
3621 // but with `qself` set to `None`.
3623 // However, setting `qself` to none (but not changing the
3624 // span) loses the information about where this path
3625 // *actually* appears, so for the purposes of the crate
3626 // lint we pass along information that this is the trait
3627 // name from a fully qualified path, and this also
3628 // contains the full span (the `CrateLint::QPathTrait`).
3629 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3630 let res = self.smart_resolve_path_fragment(
3633 &path[..=qself.position],
3635 PathSource::TraitItem(ns),
3636 CrateLint::QPathTrait {
3638 qpath_span: qself.path_span,
3642 // The remaining segments (the `C` in our example) will
3643 // have to be resolved by type-check, since that requires doing
3644 // trait resolution.
3645 return Some(PathResolution::with_unresolved_segments(
3646 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3650 let result = match self.resolve_path_without_parent_scope(
3657 PathResult::NonModule(path_res) => path_res,
3658 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3659 PathResolution::new(module.def().unwrap())
3661 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3662 // don't report an error right away, but try to fallback to a primitive type.
3663 // So, we are still able to successfully resolve something like
3665 // use std::u8; // bring module u8 in scope
3666 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3667 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3668 // // not to non-existent std::u8::max_value
3671 // Such behavior is required for backward compatibility.
3672 // The same fallback is used when `a` resolves to nothing.
3673 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3674 PathResult::Failed(..)
3675 if (ns == TypeNS || path.len() > 1) &&
3676 self.primitive_type_table.primitive_types
3677 .contains_key(&path[0].ident.name) => {
3678 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3679 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3681 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3682 PathResolution::new(module.def().unwrap()),
3683 PathResult::Failed(span, msg, false) => {
3684 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3685 err_path_resolution()
3687 PathResult::Module(..) | PathResult::Failed(..) => return None,
3688 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3691 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3692 path[0].ident.name != keywords::PathRoot.name() &&
3693 path[0].ident.name != keywords::DollarCrate.name() {
3694 let unqualified_result = {
3695 match self.resolve_path_without_parent_scope(
3696 &[*path.last().unwrap()],
3702 PathResult::NonModule(path_res) => path_res.base_def(),
3703 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3704 module.def().unwrap(),
3705 _ => return Some(result),
3708 if result.base_def() == unqualified_result {
3709 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3710 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3717 fn resolve_path_without_parent_scope(
3720 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3723 crate_lint: CrateLint,
3724 ) -> PathResult<'a> {
3725 // Macro and import paths must have full parent scope available during resolution,
3726 // other paths will do okay with parent module alone.
3727 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3728 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3729 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3735 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3736 parent_scope: &ParentScope<'a>,
3739 crate_lint: CrateLint,
3740 ) -> PathResult<'a> {
3741 let mut module = None;
3742 let mut allow_super = true;
3743 let mut second_binding = None;
3744 self.current_module = parent_scope.module;
3747 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3748 path_span={:?}, crate_lint={:?})",
3756 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3757 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3758 let record_segment_def = |this: &mut Self, def| {
3760 if let Some(id) = id {
3761 if !this.def_map.contains_key(&id) {
3762 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3763 this.record_def(id, PathResolution::new(def));
3769 let is_last = i == path.len() - 1;
3770 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3771 let name = ident.name;
3773 allow_super &= ns == TypeNS &&
3774 (name == keywords::SelfLower.name() ||
3775 name == keywords::Super.name());
3778 if allow_super && name == keywords::Super.name() {
3779 let mut ctxt = ident.span.ctxt().modern();
3780 let self_module = match i {
3781 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3783 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3787 if let Some(self_module) = self_module {
3788 if let Some(parent) = self_module.parent {
3789 module = Some(ModuleOrUniformRoot::Module(
3790 self.resolve_self(&mut ctxt, parent)));
3794 let msg = "there are too many initial `super`s.".to_string();
3795 return PathResult::Failed(ident.span, msg, false);
3798 if name == keywords::SelfLower.name() {
3799 let mut ctxt = ident.span.ctxt().modern();
3800 module = Some(ModuleOrUniformRoot::Module(
3801 self.resolve_self(&mut ctxt, self.current_module)));
3804 if name == keywords::Extern.name() ||
3805 name == keywords::PathRoot.name() && ident.span.rust_2018() {
3806 module = Some(ModuleOrUniformRoot::ExternPrelude);
3809 if name == keywords::PathRoot.name() &&
3810 ident.span.rust_2015() && self.session.rust_2018() {
3811 // `::a::b` from 2015 macro on 2018 global edition
3812 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3815 if name == keywords::PathRoot.name() ||
3816 name == keywords::Crate.name() ||
3817 name == keywords::DollarCrate.name() {
3818 // `::a::b`, `crate::a::b` or `$crate::a::b`
3819 module = Some(ModuleOrUniformRoot::Module(
3820 self.resolve_crate_root(ident)));
3826 // Report special messages for path segment keywords in wrong positions.
3827 if ident.is_path_segment_keyword() && i != 0 {
3828 let name_str = if name == keywords::PathRoot.name() {
3829 "crate root".to_string()
3831 format!("`{}`", name)
3833 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3834 format!("global paths cannot start with {}", name_str)
3836 format!("{} in paths can only be used in start position", name_str)
3838 return PathResult::Failed(ident.span, msg, false);
3841 let binding = if let Some(module) = module {
3842 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3843 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3844 assert!(ns == TypeNS);
3845 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3846 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3847 record_used, path_span)
3849 let record_used_id =
3850 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3851 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3852 // we found a locally-imported or available item/module
3853 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3854 // we found a local variable or type param
3855 Some(LexicalScopeBinding::Def(def))
3856 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3857 record_segment_def(self, def);
3858 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3862 _ => Err(Determinacy::determined(record_used)),
3869 second_binding = Some(binding);
3871 let def = binding.def();
3872 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3873 if let Some(next_module) = binding.module() {
3874 module = Some(ModuleOrUniformRoot::Module(next_module));
3875 record_segment_def(self, def);
3876 } else if def == Def::ToolMod && i + 1 != path.len() {
3877 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3878 return PathResult::NonModule(PathResolution::new(def));
3879 } else if def == Def::Err {
3880 return PathResult::NonModule(err_path_resolution());
3881 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3882 self.lint_if_path_starts_with_module(
3888 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3889 def, path.len() - i - 1
3892 return PathResult::Failed(ident.span,
3893 format!("not a module `{}`", ident),
3897 Err(Undetermined) => return PathResult::Indeterminate,
3898 Err(Determined) => {
3899 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3900 if opt_ns.is_some() && !module.is_normal() {
3901 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3902 module.def().unwrap(), path.len() - i
3906 let module_def = match module {
3907 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3910 let msg = if module_def == self.graph_root.def() {
3911 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3912 let mut candidates =
3913 self.lookup_import_candidates(ident, TypeNS, is_mod);
3914 candidates.sort_by_cached_key(|c| {
3915 (c.path.segments.len(), c.path.to_string())
3917 if let Some(candidate) = candidates.get(0) {
3918 format!("did you mean `{}`?", candidate.path)
3919 } else if !ident.is_reserved() {
3920 format!("maybe a missing `extern crate {};`?", ident)
3922 // the parser will already have complained about the keyword being used
3923 return PathResult::NonModule(err_path_resolution());
3926 format!("use of undeclared type or module `{}`", ident)
3928 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
3930 return PathResult::Failed(ident.span, msg, is_last);
3935 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3937 PathResult::Module(match module {
3938 Some(module) => module,
3939 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3940 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3944 fn lint_if_path_starts_with_module(
3946 crate_lint: CrateLint,
3949 second_binding: Option<&NameBinding>,
3951 let (diag_id, diag_span) = match crate_lint {
3952 CrateLint::No => return,
3953 CrateLint::SimplePath(id) => (id, path_span),
3954 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3955 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3958 let first_name = match path.get(0) {
3959 // In the 2018 edition this lint is a hard error, so nothing to do
3960 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3964 // We're only interested in `use` paths which should start with
3965 // `{{root}}` or `extern` currently.
3966 if first_name != keywords::Extern.name() && first_name != keywords::PathRoot.name() {
3971 // If this import looks like `crate::...` it's already good
3972 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3973 // Otherwise go below to see if it's an extern crate
3975 // If the path has length one (and it's `PathRoot` most likely)
3976 // then we don't know whether we're gonna be importing a crate or an
3977 // item in our crate. Defer this lint to elsewhere
3981 // If the first element of our path was actually resolved to an
3982 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3983 // warning, this looks all good!
3984 if let Some(binding) = second_binding {
3985 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3986 // Careful: we still want to rewrite paths from
3987 // renamed extern crates.
3988 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3994 let diag = lint::builtin::BuiltinLintDiagnostics
3995 ::AbsPathWithModule(diag_span);
3996 self.session.buffer_lint_with_diagnostic(
3997 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3999 "absolute paths must start with `self`, `super`, \
4000 `crate`, or an external crate name in the 2018 edition",
4004 // Resolve a local definition, potentially adjusting for closures.
4005 fn adjust_local_def(&mut self,
4010 span: Span) -> Def {
4011 let ribs = &self.ribs[ns][rib_index + 1..];
4013 // An invalid forward use of a type parameter from a previous default.
4014 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4016 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4018 assert_eq!(def, Def::Err);
4024 span_bug!(span, "unexpected {:?} in bindings", def)
4026 Def::Local(node_id) => {
4029 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4030 ForwardTyParamBanRibKind => {
4031 // Nothing to do. Continue.
4033 ClosureRibKind(function_id) => {
4036 let seen = self.freevars_seen
4039 if let Some(&index) = seen.get(&node_id) {
4040 def = Def::Upvar(node_id, index, function_id);
4043 let vec = self.freevars
4046 let depth = vec.len();
4047 def = Def::Upvar(node_id, depth, function_id);
4054 seen.insert(node_id, depth);
4057 ItemRibKind | TraitOrImplItemRibKind => {
4058 // This was an attempt to access an upvar inside a
4059 // named function item. This is not allowed, so we
4062 resolve_error(self, span,
4063 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4067 ConstantItemRibKind => {
4068 // Still doesn't deal with upvars
4070 resolve_error(self, span,
4071 ResolutionError::AttemptToUseNonConstantValueInConstant);
4078 Def::TyParam(..) | Def::SelfTy(..) => {
4081 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4082 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4083 ConstantItemRibKind => {
4084 // Nothing to do. Continue.
4087 // This was an attempt to use a type parameter outside
4090 resolve_error(self, span,
4091 ResolutionError::TypeParametersFromOuterFunction(def));
4103 fn lookup_assoc_candidate<FilterFn>(&mut self,
4106 filter_fn: FilterFn)
4107 -> Option<AssocSuggestion>
4108 where FilterFn: Fn(Def) -> bool
4110 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4112 TyKind::Path(None, _) => Some(t.id),
4113 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4114 // This doesn't handle the remaining `Ty` variants as they are not
4115 // that commonly the self_type, it might be interesting to provide
4116 // support for those in future.
4121 // Fields are generally expected in the same contexts as locals.
4122 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4123 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4124 // Look for a field with the same name in the current self_type.
4125 if let Some(resolution) = self.def_map.get(&node_id) {
4126 match resolution.base_def() {
4127 Def::Struct(did) | Def::Union(did)
4128 if resolution.unresolved_segments() == 0 => {
4129 if let Some(field_names) = self.field_names.get(&did) {
4130 if field_names.iter().any(|&field_name| ident.name == field_name) {
4131 return Some(AssocSuggestion::Field);
4141 // Look for associated items in the current trait.
4142 if let Some((module, _)) = self.current_trait_ref {
4143 if let Ok(binding) = self.resolve_ident_in_module(
4144 ModuleOrUniformRoot::Module(module),
4151 let def = binding.def();
4153 return Some(if self.has_self.contains(&def.def_id()) {
4154 AssocSuggestion::MethodWithSelf
4156 AssocSuggestion::AssocItem
4165 fn lookup_typo_candidate<FilterFn>(&mut self,
4168 filter_fn: FilterFn,
4171 where FilterFn: Fn(Def) -> bool
4173 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4174 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4175 if let Some(binding) = resolution.borrow().binding {
4176 if filter_fn(binding.def()) {
4177 names.push(ident.name);
4183 let mut names = Vec::new();
4184 if path.len() == 1 {
4185 // Search in lexical scope.
4186 // Walk backwards up the ribs in scope and collect candidates.
4187 for rib in self.ribs[ns].iter().rev() {
4188 // Locals and type parameters
4189 for (ident, def) in &rib.bindings {
4190 if filter_fn(*def) {
4191 names.push(ident.name);
4195 if let ModuleRibKind(module) = rib.kind {
4196 // Items from this module
4197 add_module_candidates(module, &mut names);
4199 if let ModuleKind::Block(..) = module.kind {
4200 // We can see through blocks
4202 // Items from the prelude
4203 if !module.no_implicit_prelude {
4204 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4205 if let Some(prelude) = self.prelude {
4206 add_module_candidates(prelude, &mut names);
4213 // Add primitive types to the mix
4214 if filter_fn(Def::PrimTy(Bool)) {
4216 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4220 // Search in module.
4221 let mod_path = &path[..path.len() - 1];
4222 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4223 mod_path, Some(TypeNS), false, span, CrateLint::No
4225 if let ModuleOrUniformRoot::Module(module) = module {
4226 add_module_candidates(module, &mut names);
4231 let name = path[path.len() - 1].ident.name;
4232 // Make sure error reporting is deterministic.
4233 names.sort_by_cached_key(|name| name.as_str());
4234 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4235 Some(found) if found != name => Some(found),
4240 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4241 where F: FnOnce(&mut Resolver)
4243 if let Some(label) = label {
4244 self.unused_labels.insert(id, label.ident.span);
4245 let def = Def::Label(id);
4246 self.with_label_rib(|this| {
4247 let ident = label.ident.modern_and_legacy();
4248 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4256 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4257 self.with_resolved_label(label, id, |this| this.visit_block(block));
4260 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4261 // First, record candidate traits for this expression if it could
4262 // result in the invocation of a method call.
4264 self.record_candidate_traits_for_expr_if_necessary(expr);
4266 // Next, resolve the node.
4268 ExprKind::Path(ref qself, ref path) => {
4269 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4270 visit::walk_expr(self, expr);
4273 ExprKind::Struct(ref path, ..) => {
4274 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4275 visit::walk_expr(self, expr);
4278 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4279 let def = self.search_label(label.ident, |rib, ident| {
4280 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4284 // Search again for close matches...
4285 // Picks the first label that is "close enough", which is not necessarily
4286 // the closest match
4287 let close_match = self.search_label(label.ident, |rib, ident| {
4288 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4289 find_best_match_for_name(names, &*ident.as_str(), None)
4291 self.record_def(expr.id, err_path_resolution());
4294 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4297 Some(Def::Label(id)) => {
4298 // Since this def is a label, it is never read.
4299 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4300 self.unused_labels.remove(&id);
4303 span_bug!(expr.span, "label wasn't mapped to a label def!");
4307 // visit `break` argument if any
4308 visit::walk_expr(self, expr);
4311 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4312 self.visit_expr(subexpression);
4314 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4315 let mut bindings_list = FxHashMap::default();
4317 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4319 // This has to happen *after* we determine which pat_idents are variants
4320 self.check_consistent_bindings(pats);
4321 self.visit_block(if_block);
4322 self.ribs[ValueNS].pop();
4324 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4327 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4329 ExprKind::While(ref subexpression, ref block, label) => {
4330 self.with_resolved_label(label, expr.id, |this| {
4331 this.visit_expr(subexpression);
4332 this.visit_block(block);
4336 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4337 self.with_resolved_label(label, expr.id, |this| {
4338 this.visit_expr(subexpression);
4339 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4340 let mut bindings_list = FxHashMap::default();
4342 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4344 // This has to happen *after* we determine which pat_idents are variants.
4345 this.check_consistent_bindings(pats);
4346 this.visit_block(block);
4347 this.ribs[ValueNS].pop();
4351 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4352 self.visit_expr(subexpression);
4353 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4354 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4356 self.resolve_labeled_block(label, expr.id, block);
4358 self.ribs[ValueNS].pop();
4361 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4363 // Equivalent to `visit::walk_expr` + passing some context to children.
4364 ExprKind::Field(ref subexpression, _) => {
4365 self.resolve_expr(subexpression, Some(expr));
4367 ExprKind::MethodCall(ref segment, ref arguments) => {
4368 let mut arguments = arguments.iter();
4369 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4370 for argument in arguments {
4371 self.resolve_expr(argument, None);
4373 self.visit_path_segment(expr.span, segment);
4376 ExprKind::Call(ref callee, ref arguments) => {
4377 self.resolve_expr(callee, Some(expr));
4378 for argument in arguments {
4379 self.resolve_expr(argument, None);
4382 ExprKind::Type(ref type_expr, _) => {
4383 self.current_type_ascription.push(type_expr.span);
4384 visit::walk_expr(self, expr);
4385 self.current_type_ascription.pop();
4387 // Resolve the body of async exprs inside the async closure to which they desugar
4388 ExprKind::Async(_, async_closure_id, ref block) => {
4389 let rib_kind = ClosureRibKind(async_closure_id);
4390 self.ribs[ValueNS].push(Rib::new(rib_kind));
4391 self.label_ribs.push(Rib::new(rib_kind));
4392 self.visit_block(&block);
4393 self.label_ribs.pop();
4394 self.ribs[ValueNS].pop();
4396 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4397 // resolve the arguments within the proper scopes so that usages of them inside the
4398 // closure are detected as upvars rather than normal closure arg usages.
4400 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4401 ref fn_decl, ref body, _span,
4403 let rib_kind = ClosureRibKind(expr.id);
4404 self.ribs[ValueNS].push(Rib::new(rib_kind));
4405 self.label_ribs.push(Rib::new(rib_kind));
4406 // Resolve arguments:
4407 let mut bindings_list = FxHashMap::default();
4408 for argument in &fn_decl.inputs {
4409 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4410 self.visit_ty(&argument.ty);
4412 // No need to resolve return type-- the outer closure return type is
4413 // FunctionRetTy::Default
4415 // Now resolve the inner closure
4417 let rib_kind = ClosureRibKind(inner_closure_id);
4418 self.ribs[ValueNS].push(Rib::new(rib_kind));
4419 self.label_ribs.push(Rib::new(rib_kind));
4420 // No need to resolve arguments: the inner closure has none.
4421 // Resolve the return type:
4422 visit::walk_fn_ret_ty(self, &fn_decl.output);
4424 self.visit_expr(body);
4425 self.label_ribs.pop();
4426 self.ribs[ValueNS].pop();
4428 self.label_ribs.pop();
4429 self.ribs[ValueNS].pop();
4432 visit::walk_expr(self, expr);
4437 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4439 ExprKind::Field(_, ident) => {
4440 // FIXME(#6890): Even though you can't treat a method like a
4441 // field, we need to add any trait methods we find that match
4442 // the field name so that we can do some nice error reporting
4443 // later on in typeck.
4444 let traits = self.get_traits_containing_item(ident, ValueNS);
4445 self.trait_map.insert(expr.id, traits);
4447 ExprKind::MethodCall(ref segment, ..) => {
4448 debug!("(recording candidate traits for expr) recording traits for {}",
4450 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4451 self.trait_map.insert(expr.id, traits);
4459 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4460 -> Vec<TraitCandidate> {
4461 debug!("(getting traits containing item) looking for '{}'", ident.name);
4463 let mut found_traits = Vec::new();
4464 // Look for the current trait.
4465 if let Some((module, _)) = self.current_trait_ref {
4466 if self.resolve_ident_in_module(
4467 ModuleOrUniformRoot::Module(module),
4474 let def_id = module.def_id().unwrap();
4475 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4479 ident.span = ident.span.modern();
4480 let mut search_module = self.current_module;
4482 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4483 search_module = unwrap_or!(
4484 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4488 if let Some(prelude) = self.prelude {
4489 if !search_module.no_implicit_prelude {
4490 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4497 fn get_traits_in_module_containing_item(&mut self,
4501 found_traits: &mut Vec<TraitCandidate>) {
4502 assert!(ns == TypeNS || ns == ValueNS);
4503 let mut traits = module.traits.borrow_mut();
4504 if traits.is_none() {
4505 let mut collected_traits = Vec::new();
4506 module.for_each_child(|name, ns, binding| {
4507 if ns != TypeNS { return }
4508 if let Def::Trait(_) = binding.def() {
4509 collected_traits.push((name, binding));
4512 *traits = Some(collected_traits.into_boxed_slice());
4515 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4516 let module = binding.module().unwrap();
4517 let mut ident = ident;
4518 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4521 if self.resolve_ident_in_module_unadjusted(
4522 ModuleOrUniformRoot::Module(module),
4528 let import_id = match binding.kind {
4529 NameBindingKind::Import { directive, .. } => {
4530 self.maybe_unused_trait_imports.insert(directive.id);
4531 self.add_to_glob_map(directive.id, trait_name);
4536 let trait_def_id = module.def_id().unwrap();
4537 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4542 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4543 lookup_ident: Ident,
4544 namespace: Namespace,
4545 start_module: &'a ModuleData<'a>,
4547 filter_fn: FilterFn)
4548 -> Vec<ImportSuggestion>
4549 where FilterFn: Fn(Def) -> bool
4551 let mut candidates = Vec::new();
4552 let mut seen_modules = FxHashSet::default();
4553 let not_local_module = crate_name != keywords::Crate.ident();
4554 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4556 while let Some((in_module,
4558 in_module_is_extern)) = worklist.pop() {
4559 self.populate_module_if_necessary(in_module);
4561 // We have to visit module children in deterministic order to avoid
4562 // instabilities in reported imports (#43552).
4563 in_module.for_each_child_stable(|ident, ns, name_binding| {
4564 // avoid imports entirely
4565 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4566 // avoid non-importable candidates as well
4567 if !name_binding.is_importable() { return; }
4569 // collect results based on the filter function
4570 if ident.name == lookup_ident.name && ns == namespace {
4571 if filter_fn(name_binding.def()) {
4573 let mut segms = path_segments.clone();
4574 if lookup_ident.span.rust_2018() {
4575 // crate-local absolute paths start with `crate::` in edition 2018
4576 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4578 0, ast::PathSegment::from_ident(crate_name)
4582 segms.push(ast::PathSegment::from_ident(ident));
4584 span: name_binding.span,
4587 // the entity is accessible in the following cases:
4588 // 1. if it's defined in the same crate, it's always
4589 // accessible (since private entities can be made public)
4590 // 2. if it's defined in another crate, it's accessible
4591 // only if both the module is public and the entity is
4592 // declared as public (due to pruning, we don't explore
4593 // outside crate private modules => no need to check this)
4594 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4595 candidates.push(ImportSuggestion { path });
4600 // collect submodules to explore
4601 if let Some(module) = name_binding.module() {
4603 let mut path_segments = path_segments.clone();
4604 path_segments.push(ast::PathSegment::from_ident(ident));
4606 let is_extern_crate_that_also_appears_in_prelude =
4607 name_binding.is_extern_crate() &&
4608 lookup_ident.span.rust_2018();
4610 let is_visible_to_user =
4611 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4613 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4614 // add the module to the lookup
4615 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4616 if seen_modules.insert(module.def_id().unwrap()) {
4617 worklist.push((module, path_segments, is_extern));
4627 /// When name resolution fails, this method can be used to look up candidate
4628 /// entities with the expected name. It allows filtering them using the
4629 /// supplied predicate (which should be used to only accept the types of
4630 /// definitions expected e.g., traits). The lookup spans across all crates.
4632 /// NOTE: The method does not look into imports, but this is not a problem,
4633 /// since we report the definitions (thus, the de-aliased imports).
4634 fn lookup_import_candidates<FilterFn>(&mut self,
4635 lookup_ident: Ident,
4636 namespace: Namespace,
4637 filter_fn: FilterFn)
4638 -> Vec<ImportSuggestion>
4639 where FilterFn: Fn(Def) -> bool
4641 let mut suggestions = self.lookup_import_candidates_from_module(
4642 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4644 if lookup_ident.span.rust_2018() {
4645 let extern_prelude_names = self.extern_prelude.clone();
4646 for (ident, _) in extern_prelude_names.into_iter() {
4647 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4649 let crate_root = self.get_module(DefId {
4651 index: CRATE_DEF_INDEX,
4653 self.populate_module_if_necessary(&crate_root);
4655 suggestions.extend(self.lookup_import_candidates_from_module(
4656 lookup_ident, namespace, crate_root, ident, &filter_fn));
4664 fn find_module(&mut self,
4666 -> Option<(Module<'a>, ImportSuggestion)>
4668 let mut result = None;
4669 let mut seen_modules = FxHashSet::default();
4670 let mut worklist = vec![(self.graph_root, Vec::new())];
4672 while let Some((in_module, path_segments)) = worklist.pop() {
4673 // abort if the module is already found
4674 if result.is_some() { break; }
4676 self.populate_module_if_necessary(in_module);
4678 in_module.for_each_child_stable(|ident, _, name_binding| {
4679 // abort if the module is already found or if name_binding is private external
4680 if result.is_some() || !name_binding.vis.is_visible_locally() {
4683 if let Some(module) = name_binding.module() {
4685 let mut path_segments = path_segments.clone();
4686 path_segments.push(ast::PathSegment::from_ident(ident));
4687 if module.def() == Some(module_def) {
4689 span: name_binding.span,
4690 segments: path_segments,
4692 result = Some((module, ImportSuggestion { path }));
4694 // add the module to the lookup
4695 if seen_modules.insert(module.def_id().unwrap()) {
4696 worklist.push((module, path_segments));
4706 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4707 if let Def::Enum(..) = enum_def {} else {
4708 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4711 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4712 self.populate_module_if_necessary(enum_module);
4714 let mut variants = Vec::new();
4715 enum_module.for_each_child_stable(|ident, _, name_binding| {
4716 if let Def::Variant(..) = name_binding.def() {
4717 let mut segms = enum_import_suggestion.path.segments.clone();
4718 segms.push(ast::PathSegment::from_ident(ident));
4719 variants.push(Path {
4720 span: name_binding.span,
4729 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4730 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4731 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4732 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4736 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4738 ast::VisibilityKind::Public => ty::Visibility::Public,
4739 ast::VisibilityKind::Crate(..) => {
4740 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4742 ast::VisibilityKind::Inherited => {
4743 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4745 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4746 // For visibilities we are not ready to provide correct implementation of "uniform
4747 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4748 // On 2015 edition visibilities are resolved as crate-relative by default,
4749 // so we are prepending a root segment if necessary.
4750 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4751 let crate_root = if ident.is_path_segment_keyword() {
4753 } else if ident.span.rust_2018() {
4754 let msg = "relative paths are not supported in visibilities on 2018 edition";
4755 self.session.struct_span_err(ident.span, msg)
4756 .span_suggestion(path.span, "try", format!("crate::{}", path))
4758 return ty::Visibility::Public;
4760 let ctxt = ident.span.ctxt();
4761 Some(Segment::from_ident(Ident::new(
4762 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4766 let segments = crate_root.into_iter()
4767 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4768 let def = self.smart_resolve_path_fragment(
4773 PathSource::Visibility,
4774 CrateLint::SimplePath(id),
4776 if def == Def::Err {
4777 ty::Visibility::Public
4779 let vis = ty::Visibility::Restricted(def.def_id());
4780 if self.is_accessible(vis) {
4783 self.session.span_err(path.span, "visibilities can only be restricted \
4784 to ancestor modules");
4785 ty::Visibility::Public
4792 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4793 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4796 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4797 vis.is_accessible_from(module.normal_ancestor_id, self)
4800 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4801 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4802 if !ptr::eq(module, old_module) {
4803 span_bug!(binding.span, "parent module is reset for binding");
4808 fn disambiguate_legacy_vs_modern(
4810 legacy: &'a NameBinding<'a>,
4811 modern: &'a NameBinding<'a>,
4813 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4814 // is disambiguated to mitigate regressions from macro modularization.
4815 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4816 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4817 self.binding_parent_modules.get(&PtrKey(modern))) {
4818 (Some(legacy), Some(modern)) =>
4819 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4820 modern.is_ancestor_of(legacy),
4825 fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
4826 if b.span.is_dummy() {
4827 let add_built_in = match b.def() {
4828 // These already contain the "built-in" prefix or look bad with it.
4829 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4832 let (built_in, from) = if from_prelude {
4833 ("", " from prelude")
4834 } else if b.is_extern_crate() && !b.is_import() &&
4835 self.session.opts.externs.get(&ident.as_str()).is_some() {
4836 ("", " passed with `--extern`")
4837 } else if add_built_in {
4843 let article = if built_in.is_empty() { b.article() } else { "a" };
4844 format!("{a}{built_in} {thing}{from}",
4845 a = article, thing = b.descr(), built_in = built_in, from = from)
4847 let introduced = if b.is_import() { "imported" } else { "defined" };
4848 format!("the {thing} {introduced} here",
4849 thing = b.descr(), introduced = introduced)
4853 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
4854 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4855 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4856 // We have to print the span-less alternative first, otherwise formatting looks bad.
4857 (b2, b1, misc2, misc1, true)
4859 (b1, b2, misc1, misc2, false)
4862 let mut err = struct_span_err!(self.session, ident.span, E0659,
4863 "`{ident}` is ambiguous ({why})",
4864 ident = ident, why = kind.descr());
4865 err.span_label(ident.span, "ambiguous name");
4867 let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
4868 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4869 let note_msg = format!("`{ident}` could{also} refer to {what}",
4870 ident = ident, also = also, what = what);
4872 let mut help_msgs = Vec::new();
4873 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4874 kind == AmbiguityKind::GlobVsExpanded ||
4875 kind == AmbiguityKind::GlobVsOuter &&
4876 swapped != also.is_empty()) {
4877 help_msgs.push(format!("consider adding an explicit import of \
4878 `{ident}` to disambiguate", ident = ident))
4880 if b.is_extern_crate() && ident.span.rust_2018() {
4881 help_msgs.push(format!(
4882 "use `::{ident}` to refer to this {thing} unambiguously",
4883 ident = ident, thing = b.descr(),
4886 if misc == AmbiguityErrorMisc::SuggestCrate {
4887 help_msgs.push(format!(
4888 "use `crate::{ident}` to refer to this {thing} unambiguously",
4889 ident = ident, thing = b.descr(),
4891 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4892 help_msgs.push(format!(
4893 "use `self::{ident}` to refer to this {thing} unambiguously",
4894 ident = ident, thing = b.descr(),
4898 if b.span.is_dummy() {
4899 err.note(¬e_msg);
4901 err.span_note(b.span, ¬e_msg);
4903 for (i, help_msg) in help_msgs.iter().enumerate() {
4904 let or = if i == 0 { "" } else { "or " };
4905 err.help(&format!("{}{}", or, help_msg));
4909 could_refer_to(b1, misc1, "");
4910 could_refer_to(b2, misc2, " also");
4914 fn report_errors(&mut self, krate: &Crate) {
4915 self.report_with_use_injections(krate);
4917 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4918 let msg = "macro-expanded `macro_export` macros from the current crate \
4919 cannot be referred to by absolute paths";
4920 self.session.buffer_lint_with_diagnostic(
4921 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4922 CRATE_NODE_ID, span_use, msg,
4923 lint::builtin::BuiltinLintDiagnostics::
4924 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4928 for ambiguity_error in &self.ambiguity_errors {
4929 self.report_ambiguity_error(ambiguity_error);
4932 let mut reported_spans = FxHashSet::default();
4933 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4934 if reported_spans.insert(dedup_span) {
4935 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4936 binding.descr(), ident.name);
4941 fn report_with_use_injections(&mut self, krate: &Crate) {
4942 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4943 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4944 if !candidates.is_empty() {
4945 show_candidates(&mut err, span, &candidates, better, found_use);
4951 fn report_conflict<'b>(&mut self,
4955 new_binding: &NameBinding<'b>,
4956 old_binding: &NameBinding<'b>) {
4957 // Error on the second of two conflicting names
4958 if old_binding.span.lo() > new_binding.span.lo() {
4959 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4962 let container = match parent.kind {
4963 ModuleKind::Def(Def::Mod(_), _) => "module",
4964 ModuleKind::Def(Def::Trait(_), _) => "trait",
4965 ModuleKind::Block(..) => "block",
4969 let old_noun = match old_binding.is_import() {
4971 false => "definition",
4974 let new_participle = match new_binding.is_import() {
4979 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4981 if let Some(s) = self.name_already_seen.get(&name) {
4987 let old_kind = match (ns, old_binding.module()) {
4988 (ValueNS, _) => "value",
4989 (MacroNS, _) => "macro",
4990 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4991 (TypeNS, Some(module)) if module.is_normal() => "module",
4992 (TypeNS, Some(module)) if module.is_trait() => "trait",
4993 (TypeNS, _) => "type",
4996 let msg = format!("the name `{}` is defined multiple times", name);
4998 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4999 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5000 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5001 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5002 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5004 _ => match (old_binding.is_import(), new_binding.is_import()) {
5005 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5006 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5007 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5011 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5016 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5017 if !old_binding.span.is_dummy() {
5018 err.span_label(self.session.source_map().def_span(old_binding.span),
5019 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
5022 // See https://github.com/rust-lang/rust/issues/32354
5023 if old_binding.is_import() || new_binding.is_import() {
5024 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
5030 let cm = self.session.source_map();
5031 let rename_msg = "you can use `as` to change the binding name of the import";
5035 NameBindingKind::Import { directive, ..},
5038 cm.span_to_snippet(binding.span),
5039 binding.kind.clone(),
5040 binding.span.is_dummy(),
5042 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5043 format!("Other{}", name)
5045 format!("other_{}", name)
5048 err.span_suggestion_with_applicability(
5051 match directive.subclass {
5052 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5053 format!("self as {}", suggested_name),
5054 ImportDirectiveSubclass::SingleImport { source, .. } =>
5057 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
5059 if snippet.ends_with(";") {
5065 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5067 "extern crate {} as {};",
5068 source.unwrap_or(target.name),
5071 _ => unreachable!(),
5073 Applicability::MaybeIncorrect,
5076 err.span_label(binding.span, rename_msg);
5081 self.name_already_seen.insert(name, span);
5084 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5085 -> Option<&'a NameBinding<'a>> {
5086 if ident.is_path_segment_keyword() {
5087 // Make sure `self`, `super` etc produce an error when passed to here.
5090 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5091 if let Some(binding) = entry.extern_crate_item {
5094 let crate_id = if !speculative {
5095 self.crate_loader.process_path_extern(ident.name, ident.span)
5096 } else if let Some(crate_id) =
5097 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5102 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5103 self.populate_module_if_necessary(&crate_root);
5104 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5105 .to_name_binding(self.arenas))
5111 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5112 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5115 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5116 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5119 fn names_to_string(idents: &[Ident]) -> String {
5120 let mut result = String::new();
5121 for (i, ident) in idents.iter()
5122 .filter(|ident| ident.name != keywords::PathRoot.name())
5125 result.push_str("::");
5127 result.push_str(&ident.as_str());
5132 fn path_names_to_string(path: &Path) -> String {
5133 names_to_string(&path.segments.iter()
5134 .map(|seg| seg.ident)
5135 .collect::<Vec<_>>())
5138 /// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5139 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5140 let variant_path = &suggestion.path;
5141 let variant_path_string = path_names_to_string(variant_path);
5143 let path_len = suggestion.path.segments.len();
5144 let enum_path = ast::Path {
5145 span: suggestion.path.span,
5146 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5148 let enum_path_string = path_names_to_string(&enum_path);
5150 (variant_path_string, enum_path_string)
5154 /// When an entity with a given name is not available in scope, we search for
5155 /// entities with that name in all crates. This method allows outputting the
5156 /// results of this search in a programmer-friendly way
5157 fn show_candidates(err: &mut DiagnosticBuilder,
5158 // This is `None` if all placement locations are inside expansions
5160 candidates: &[ImportSuggestion],
5164 // we want consistent results across executions, but candidates are produced
5165 // by iterating through a hash map, so make sure they are ordered:
5166 let mut path_strings: Vec<_> =
5167 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5168 path_strings.sort();
5170 let better = if better { "better " } else { "" };
5171 let msg_diff = match path_strings.len() {
5172 1 => " is found in another module, you can import it",
5173 _ => "s are found in other modules, you can import them",
5175 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5177 if let Some(span) = span {
5178 for candidate in &mut path_strings {
5179 // produce an additional newline to separate the new use statement
5180 // from the directly following item.
5181 let additional_newline = if found_use {
5186 *candidate = format!("use {};\n{}", candidate, additional_newline);
5189 err.span_suggestions_with_applicability(
5192 path_strings.into_iter(),
5193 Applicability::Unspecified,
5198 for candidate in path_strings {
5200 msg.push_str(&candidate);
5205 /// A somewhat inefficient routine to obtain the name of a module.
5206 fn module_to_string(module: Module) -> Option<String> {
5207 let mut names = Vec::new();
5209 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5210 if let ModuleKind::Def(_, name) = module.kind {
5211 if let Some(parent) = module.parent {
5212 names.push(Ident::with_empty_ctxt(name));
5213 collect_mod(names, parent);
5216 // danger, shouldn't be ident?
5217 names.push(Ident::from_str("<opaque>"));
5218 collect_mod(names, module.parent.unwrap());
5221 collect_mod(&mut names, module);
5223 if names.is_empty() {
5226 Some(names_to_string(&names.into_iter()
5228 .collect::<Vec<_>>()))
5231 fn err_path_resolution() -> PathResolution {
5232 PathResolution::new(Def::Err)
5235 #[derive(PartialEq,Copy, Clone)]
5236 pub enum MakeGlobMap {
5241 #[derive(Copy, Clone, Debug)]
5243 /// Do not issue the lint
5246 /// This lint applies to some random path like `impl ::foo::Bar`
5247 /// or whatever. In this case, we can take the span of that path.
5250 /// This lint comes from a `use` statement. In this case, what we
5251 /// care about really is the *root* `use` statement; e.g., if we
5252 /// have nested things like `use a::{b, c}`, we care about the
5254 UsePath { root_id: NodeId, root_span: Span },
5256 /// This is the "trait item" from a fully qualified path. For example,
5257 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5258 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5259 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5263 fn node_id(&self) -> Option<NodeId> {
5265 CrateLint::No => None,
5266 CrateLint::SimplePath(id) |
5267 CrateLint::UsePath { root_id: id, .. } |
5268 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5273 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }