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)]
7 #![feature(rustc_diagnostic_macros)]
8 #![feature(slice_sort_by_cached_key)]
10 #![recursion_limit="256"]
12 #![deny(rust_2018_idioms)]
14 use rustc_errors as errors;
16 pub use rustc::hir::def::{Namespace, PerNS};
18 use TypeParameters::*;
21 use rustc::hir::map::{Definitions, DefCollector};
22 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
23 use rustc::middle::cstore::CrateStore;
24 use rustc::session::Session;
26 use rustc::hir::def::*;
27 use rustc::hir::def::Namespace::*;
28 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
29 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
30 use rustc::session::config::nightly_options;
32 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
33 use rustc::{bug, span_bug};
35 use rustc_metadata::creader::CrateLoader;
36 use rustc_metadata::cstore::CStore;
38 use syntax::source_map::SourceMap;
39 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
40 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
41 use syntax::ext::base::SyntaxExtension;
42 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
43 use syntax::ext::base::MacroKind;
44 use syntax::symbol::{Symbol, keywords};
45 use syntax::util::lev_distance::find_best_match_for_name;
47 use syntax::visit::{self, FnKind, Visitor};
49 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
50 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
51 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
52 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
53 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
55 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
57 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
58 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
62 use std::cell::{Cell, RefCell};
63 use std::{cmp, fmt, iter, mem, ptr};
64 use std::collections::BTreeSet;
65 use std::mem::replace;
66 use rustc_data_structures::ptr_key::PtrKey;
67 use rustc_data_structures::sync::Lrc;
69 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
70 use macros::{InvocationData, LegacyBinding, ParentScope};
72 // N.B., this module needs to be declared first so diagnostics are
73 // registered before they are used.
78 mod build_reduced_graph;
81 fn is_known_tool(name: Name) -> bool {
82 ["clippy", "rustfmt"].contains(&&*name.as_str())
92 AbsolutePath(Namespace),
97 /// A free importable items suggested in case of resolution failure.
98 struct ImportSuggestion {
102 /// A field or associated item from self type suggested in case of resolution failure.
103 enum AssocSuggestion {
110 struct BindingError {
112 origin: BTreeSet<Span>,
113 target: BTreeSet<Span>,
116 struct TypoSuggestion {
119 /// The kind of the binding ("crate", "module", etc.)
122 /// An appropriate article to refer to the binding ("a", "an", etc.)
123 article: &'static str,
126 impl PartialOrd for BindingError {
127 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
128 Some(self.cmp(other))
132 impl PartialEq for BindingError {
133 fn eq(&self, other: &BindingError) -> bool {
134 self.name == other.name
138 impl Ord for BindingError {
139 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
140 self.name.cmp(&other.name)
144 enum ResolutionError<'a> {
145 /// error E0401: can't use type parameters from outer function
146 TypeParametersFromOuterFunction(Def),
147 /// error E0403: the name is already used for a type parameter in this type parameter list
148 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
149 /// error E0407: method is not a member of trait
150 MethodNotMemberOfTrait(Name, &'a str),
151 /// error E0437: type is not a member of trait
152 TypeNotMemberOfTrait(Name, &'a str),
153 /// error E0438: const is not a member of trait
154 ConstNotMemberOfTrait(Name, &'a str),
155 /// error E0408: variable `{}` is not bound in all patterns
156 VariableNotBoundInPattern(&'a BindingError),
157 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
158 VariableBoundWithDifferentMode(Name, Span),
159 /// error E0415: identifier is bound more than once in this parameter list
160 IdentifierBoundMoreThanOnceInParameterList(&'a str),
161 /// error E0416: identifier is bound more than once in the same pattern
162 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
163 /// error E0426: use of undeclared label
164 UndeclaredLabel(&'a str, Option<Name>),
165 /// error E0429: `self` imports are only allowed within a { } list
166 SelfImportsOnlyAllowedWithin,
167 /// error E0430: `self` import can only appear once in the list
168 SelfImportCanOnlyAppearOnceInTheList,
169 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
170 SelfImportOnlyInImportListWithNonEmptyPrefix,
171 /// error E0433: failed to resolve
172 FailedToResolve(&'a str),
173 /// error E0434: can't capture dynamic environment in a fn item
174 CannotCaptureDynamicEnvironmentInFnItem,
175 /// error E0435: attempt to use a non-constant value in a constant
176 AttemptToUseNonConstantValueInConstant,
177 /// error E0530: X bindings cannot shadow Ys
178 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
179 /// error E0128: type parameters with a default cannot use forward declared identifiers
180 ForwardDeclaredTyParam,
183 /// Combines an error with provided span and emits it
185 /// This takes the error provided, combines it with the span and any additional spans inside the
186 /// error and emits it.
187 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
189 resolution_error: ResolutionError<'a>) {
190 resolve_struct_error(resolver, span, resolution_error).emit();
193 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
195 resolution_error: ResolutionError<'a>)
196 -> DiagnosticBuilder<'sess> {
197 match resolution_error {
198 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
199 let mut err = struct_span_err!(resolver.session,
202 "can't use type parameters from outer function");
203 err.span_label(span, "use of type variable from outer function");
205 let cm = resolver.session.source_map();
207 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
208 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
209 resolver.definitions.opt_span(def_id)
212 reduce_impl_span_to_impl_keyword(cm, impl_span),
213 "`Self` type implicitly declared here, by this `impl`",
216 match (maybe_trait_defid, maybe_impl_defid) {
218 err.span_label(span, "can't use `Self` here");
221 err.span_label(span, "use a type here instead");
223 (None, None) => bug!("`impl` without trait nor type?"),
227 Def::TyParam(typaram_defid) => {
228 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
229 err.span_label(typaram_span, "type variable from outer function");
233 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
238 // Try to retrieve the span of the function signature and generate a new message with
239 // a local type parameter
240 let sugg_msg = "try using a local type parameter instead";
241 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
242 // Suggest the modification to the user
247 Applicability::MachineApplicable,
249 } else if let Some(sp) = cm.generate_fn_name_span(span) {
250 err.span_label(sp, "try adding a local type parameter in this method instead");
252 err.help("try using a local type parameter instead");
257 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
258 let mut err = struct_span_err!(resolver.session,
261 "the name `{}` is already used for a type parameter \
262 in this type parameter list",
264 err.span_label(span, "already used");
265 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
268 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
269 let mut err = struct_span_err!(resolver.session,
272 "method `{}` is not a member of trait `{}`",
275 err.span_label(span, format!("not a member of trait `{}`", trait_));
278 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
279 let mut err = struct_span_err!(resolver.session,
282 "type `{}` is not a member of trait `{}`",
285 err.span_label(span, format!("not a member of trait `{}`", trait_));
288 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
289 let mut err = struct_span_err!(resolver.session,
292 "const `{}` is not a member of trait `{}`",
295 err.span_label(span, format!("not a member of trait `{}`", trait_));
298 ResolutionError::VariableNotBoundInPattern(binding_error) => {
299 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
300 let msp = MultiSpan::from_spans(target_sp.clone());
301 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
302 let mut err = resolver.session.struct_span_err_with_code(
305 DiagnosticId::Error("E0408".into()),
307 for sp in target_sp {
308 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
310 let origin_sp = binding_error.origin.iter().cloned();
311 for sp in origin_sp {
312 err.span_label(sp, "variable not in all patterns");
316 ResolutionError::VariableBoundWithDifferentMode(variable_name,
317 first_binding_span) => {
318 let mut err = struct_span_err!(resolver.session,
321 "variable `{}` is bound in inconsistent \
322 ways within the same match arm",
324 err.span_label(span, "bound in different ways");
325 err.span_label(first_binding_span, "first binding");
328 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
329 let mut err = struct_span_err!(resolver.session,
332 "identifier `{}` is bound more than once in this parameter list",
334 err.span_label(span, "used as parameter more than once");
337 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
338 let mut err = struct_span_err!(resolver.session,
341 "identifier `{}` is bound more than once in the same pattern",
343 err.span_label(span, "used in a pattern more than once");
346 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
347 let mut err = struct_span_err!(resolver.session,
350 "use of undeclared label `{}`",
352 if let Some(lev_candidate) = lev_candidate {
353 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
355 err.span_label(span, format!("undeclared label `{}`", name));
359 ResolutionError::SelfImportsOnlyAllowedWithin => {
360 struct_span_err!(resolver.session,
364 "`self` imports are only allowed within a { } list")
366 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
367 let mut err = struct_span_err!(resolver.session, span, E0430,
368 "`self` import can only appear once in an import list");
369 err.span_label(span, "can only appear once in an import list");
372 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
373 let mut err = struct_span_err!(resolver.session, span, E0431,
374 "`self` import can only appear in an import list with \
375 a non-empty prefix");
376 err.span_label(span, "can only appear in an import list with a non-empty prefix");
379 ResolutionError::FailedToResolve(msg) => {
380 let mut err = struct_span_err!(resolver.session, span, E0433,
381 "failed to resolve: {}", msg);
382 err.span_label(span, msg);
385 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
386 let mut err = struct_span_err!(resolver.session,
390 "can't capture dynamic environment in a fn item");
391 err.help("use the `|| { ... }` closure form instead");
394 ResolutionError::AttemptToUseNonConstantValueInConstant => {
395 let mut err = struct_span_err!(resolver.session, span, E0435,
396 "attempt to use a non-constant value in a constant");
397 err.span_label(span, "non-constant value");
400 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
401 let shadows_what = binding.descr();
402 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
403 what_binding, shadows_what);
404 err.span_label(span, format!("cannot be named the same as {} {}",
405 binding.article(), shadows_what));
406 let participle = if binding.is_import() { "imported" } else { "defined" };
407 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
408 err.span_label(binding.span, msg);
411 ResolutionError::ForwardDeclaredTyParam => {
412 let mut err = struct_span_err!(resolver.session, span, E0128,
413 "type parameters with a default cannot use \
414 forward declared identifiers");
416 span, "defaulted type parameters cannot be forward declared".to_string());
422 /// Adjust the impl span so that just the `impl` keyword is taken by removing
423 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
424 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
426 /// Attention: The method used is very fragile since it essentially duplicates the work of the
427 /// parser. If you need to use this function or something similar, please consider updating the
428 /// source_map functions and this function to something more robust.
429 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
430 let impl_span = cm.span_until_char(impl_span, '<');
431 let impl_span = cm.span_until_whitespace(impl_span);
435 #[derive(Copy, Clone, Debug)]
438 binding_mode: BindingMode,
441 /// Map from the name in a pattern to its binding mode.
442 type BindingMap = FxHashMap<Ident, BindingInfo>;
444 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
455 fn descr(self) -> &'static str {
457 PatternSource::Match => "match binding",
458 PatternSource::IfLet => "if let binding",
459 PatternSource::WhileLet => "while let binding",
460 PatternSource::Let => "let binding",
461 PatternSource::For => "for binding",
462 PatternSource::FnParam => "function parameter",
467 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
468 enum AliasPossibility {
473 #[derive(Copy, Clone, Debug)]
474 enum PathSource<'a> {
475 // Type paths `Path`.
477 // Trait paths in bounds or impls.
478 Trait(AliasPossibility),
479 // Expression paths `path`, with optional parent context.
480 Expr(Option<&'a Expr>),
481 // Paths in path patterns `Path`.
483 // Paths in struct expressions and patterns `Path { .. }`.
485 // Paths in tuple struct patterns `Path(..)`.
487 // `m::A::B` in `<T as m::A>::B::C`.
488 TraitItem(Namespace),
489 // Path in `pub(path)`
493 impl<'a> PathSource<'a> {
494 fn namespace(self) -> Namespace {
496 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
497 PathSource::Visibility => TypeNS,
498 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
499 PathSource::TraitItem(ns) => ns,
503 fn global_by_default(self) -> bool {
505 PathSource::Visibility => true,
506 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
507 PathSource::Struct | PathSource::TupleStruct |
508 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
512 fn defer_to_typeck(self) -> bool {
514 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
515 PathSource::Struct | PathSource::TupleStruct => true,
516 PathSource::Trait(_) | PathSource::TraitItem(..) |
517 PathSource::Visibility => false,
521 fn descr_expected(self) -> &'static str {
523 PathSource::Type => "type",
524 PathSource::Trait(_) => "trait",
525 PathSource::Pat => "unit struct/variant or constant",
526 PathSource::Struct => "struct, variant or union type",
527 PathSource::TupleStruct => "tuple struct/variant",
528 PathSource::Visibility => "module",
529 PathSource::TraitItem(ns) => match ns {
530 TypeNS => "associated type",
531 ValueNS => "method or associated constant",
532 MacroNS => bug!("associated macro"),
534 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
535 // "function" here means "anything callable" rather than `Def::Fn`,
536 // this is not precise but usually more helpful than just "value".
537 Some(&ExprKind::Call(..)) => "function",
543 fn is_expected(self, def: Def) -> bool {
545 PathSource::Type => match def {
546 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
547 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
548 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
549 Def::SelfTy(..) | Def::Existential(..) |
550 Def::ForeignTy(..) => true,
553 PathSource::Trait(AliasPossibility::No) => match def {
554 Def::Trait(..) => true,
557 PathSource::Trait(AliasPossibility::Maybe) => match def {
558 Def::Trait(..) => true,
559 Def::TraitAlias(..) => true,
562 PathSource::Expr(..) => match def {
563 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
564 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
565 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
566 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
567 Def::SelfCtor(..) => true,
570 PathSource::Pat => match def {
571 Def::StructCtor(_, CtorKind::Const) |
572 Def::VariantCtor(_, CtorKind::Const) |
573 Def::Const(..) | Def::AssociatedConst(..) |
574 Def::SelfCtor(..) => true,
577 PathSource::TupleStruct => match def {
578 Def::StructCtor(_, CtorKind::Fn) |
579 Def::VariantCtor(_, CtorKind::Fn) |
580 Def::SelfCtor(..) => true,
583 PathSource::Struct => match def {
584 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
585 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
588 PathSource::TraitItem(ns) => match def {
589 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
590 Def::AssociatedTy(..) if ns == TypeNS => true,
593 PathSource::Visibility => match def {
594 Def::Mod(..) => true,
600 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
601 __diagnostic_used!(E0404);
602 __diagnostic_used!(E0405);
603 __diagnostic_used!(E0412);
604 __diagnostic_used!(E0422);
605 __diagnostic_used!(E0423);
606 __diagnostic_used!(E0425);
607 __diagnostic_used!(E0531);
608 __diagnostic_used!(E0532);
609 __diagnostic_used!(E0573);
610 __diagnostic_used!(E0574);
611 __diagnostic_used!(E0575);
612 __diagnostic_used!(E0576);
613 __diagnostic_used!(E0577);
614 __diagnostic_used!(E0578);
615 match (self, has_unexpected_resolution) {
616 (PathSource::Trait(_), true) => "E0404",
617 (PathSource::Trait(_), false) => "E0405",
618 (PathSource::Type, true) => "E0573",
619 (PathSource::Type, false) => "E0412",
620 (PathSource::Struct, true) => "E0574",
621 (PathSource::Struct, false) => "E0422",
622 (PathSource::Expr(..), true) => "E0423",
623 (PathSource::Expr(..), false) => "E0425",
624 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
625 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
626 (PathSource::TraitItem(..), true) => "E0575",
627 (PathSource::TraitItem(..), false) => "E0576",
628 (PathSource::Visibility, true) => "E0577",
629 (PathSource::Visibility, false) => "E0578",
634 // A minimal representation of a path segment. We use this in resolve because
635 // we synthesize 'path segments' which don't have the rest of an AST or HIR
637 #[derive(Clone, Copy, Debug)]
644 fn from_path(path: &Path) -> Vec<Segment> {
645 path.segments.iter().map(|s| s.into()).collect()
648 fn from_ident(ident: Ident) -> Segment {
655 fn names_to_string(segments: &[Segment]) -> String {
656 names_to_string(&segments.iter()
657 .map(|seg| seg.ident)
658 .collect::<Vec<_>>())
662 impl<'a> From<&'a ast::PathSegment> for Segment {
663 fn from(seg: &'a ast::PathSegment) -> Segment {
671 struct UsePlacementFinder {
672 target_module: NodeId,
677 impl UsePlacementFinder {
678 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
679 let mut finder = UsePlacementFinder {
684 visit::walk_crate(&mut finder, krate);
685 (finder.span, finder.found_use)
689 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
692 module: &'tcx ast::Mod,
694 _: &[ast::Attribute],
697 if self.span.is_some() {
700 if node_id != self.target_module {
701 visit::walk_mod(self, module);
704 // find a use statement
705 for item in &module.items {
707 ItemKind::Use(..) => {
708 // don't suggest placing a use before the prelude
709 // import or other generated ones
710 if item.span.ctxt().outer().expn_info().is_none() {
711 self.span = Some(item.span.shrink_to_lo());
712 self.found_use = true;
716 // don't place use before extern crate
717 ItemKind::ExternCrate(_) => {}
718 // but place them before the first other item
719 _ => if self.span.map_or(true, |span| item.span < span ) {
720 if item.span.ctxt().outer().expn_info().is_none() {
721 // don't insert between attributes and an item
722 if item.attrs.is_empty() {
723 self.span = Some(item.span.shrink_to_lo());
725 // find the first attribute on the item
726 for attr in &item.attrs {
727 if self.span.map_or(true, |span| attr.span < span) {
728 self.span = Some(attr.span.shrink_to_lo());
739 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
740 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
741 fn visit_item(&mut self, item: &'tcx Item) {
742 self.resolve_item(item);
744 fn visit_arm(&mut self, arm: &'tcx Arm) {
745 self.resolve_arm(arm);
747 fn visit_block(&mut self, block: &'tcx Block) {
748 self.resolve_block(block);
750 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
751 self.with_constant_rib(|this| {
752 visit::walk_anon_const(this, constant);
755 fn visit_expr(&mut self, expr: &'tcx Expr) {
756 self.resolve_expr(expr, None);
758 fn visit_local(&mut self, local: &'tcx Local) {
759 self.resolve_local(local);
761 fn visit_ty(&mut self, ty: &'tcx Ty) {
763 TyKind::Path(ref qself, ref path) => {
764 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
766 TyKind::ImplicitSelf => {
767 let self_ty = keywords::SelfUpper.ident();
768 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
769 .map_or(Def::Err, |d| d.def());
770 self.record_def(ty.id, PathResolution::new(def));
774 visit::walk_ty(self, ty);
776 fn visit_poly_trait_ref(&mut self,
777 tref: &'tcx ast::PolyTraitRef,
778 m: &'tcx ast::TraitBoundModifier) {
779 self.smart_resolve_path(tref.trait_ref.ref_id, None,
780 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
781 visit::walk_poly_trait_ref(self, tref, m);
783 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
784 let type_parameters = match foreign_item.node {
785 ForeignItemKind::Fn(_, ref generics) => {
786 HasTypeParameters(generics, ItemRibKind)
788 ForeignItemKind::Static(..) => NoTypeParameters,
789 ForeignItemKind::Ty => NoTypeParameters,
790 ForeignItemKind::Macro(..) => NoTypeParameters,
792 self.with_type_parameter_rib(type_parameters, |this| {
793 visit::walk_foreign_item(this, foreign_item);
796 fn visit_fn(&mut self,
797 function_kind: FnKind<'tcx>,
798 declaration: &'tcx FnDecl,
802 let (rib_kind, asyncness) = match function_kind {
803 FnKind::ItemFn(_, ref header, ..) =>
804 (ItemRibKind, header.asyncness),
805 FnKind::Method(_, ref sig, _, _) =>
806 (TraitOrImplItemRibKind, sig.header.asyncness),
807 FnKind::Closure(_) =>
808 // Async closures aren't resolved through `visit_fn`-- they're
809 // processed separately
810 (ClosureRibKind(node_id), IsAsync::NotAsync),
813 // Create a value rib for the function.
814 self.ribs[ValueNS].push(Rib::new(rib_kind));
816 // Create a label rib for the function.
817 self.label_ribs.push(Rib::new(rib_kind));
819 // Add each argument to the rib.
820 let mut bindings_list = FxHashMap::default();
821 for argument in &declaration.inputs {
822 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
824 self.visit_ty(&argument.ty);
826 debug!("(resolving function) recorded argument");
828 visit::walk_fn_ret_ty(self, &declaration.output);
830 // Resolve the function body, potentially inside the body of an async closure
831 if let IsAsync::Async { closure_id, .. } = asyncness {
832 let rib_kind = ClosureRibKind(closure_id);
833 self.ribs[ValueNS].push(Rib::new(rib_kind));
834 self.label_ribs.push(Rib::new(rib_kind));
837 match function_kind {
838 FnKind::ItemFn(.., body) |
839 FnKind::Method(.., body) => {
840 self.visit_block(body);
842 FnKind::Closure(body) => {
843 self.visit_expr(body);
847 // Leave the body of the async closure
848 if asyncness.is_async() {
849 self.label_ribs.pop();
850 self.ribs[ValueNS].pop();
853 debug!("(resolving function) leaving function");
855 self.label_ribs.pop();
856 self.ribs[ValueNS].pop();
858 fn visit_generics(&mut self, generics: &'tcx Generics) {
859 // For type parameter defaults, we have to ban access
860 // to following type parameters, as the Substs can only
861 // provide previous type parameters as they're built. We
862 // put all the parameters on the ban list and then remove
863 // them one by one as they are processed and become available.
864 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
865 let mut found_default = false;
866 default_ban_rib.bindings.extend(generics.params.iter()
867 .filter_map(|param| match param.kind {
868 GenericParamKind::Lifetime { .. } => None,
869 GenericParamKind::Type { ref default, .. } => {
870 found_default |= default.is_some();
872 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
879 for param in &generics.params {
881 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
882 GenericParamKind::Type { ref default, .. } => {
883 for bound in ¶m.bounds {
884 self.visit_param_bound(bound);
887 if let Some(ref ty) = default {
888 self.ribs[TypeNS].push(default_ban_rib);
890 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
893 // Allow all following defaults to refer to this type parameter.
894 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
898 for p in &generics.where_clause.predicates {
899 self.visit_where_predicate(p);
904 #[derive(Copy, Clone)]
905 enum TypeParameters<'a, 'b> {
907 HasTypeParameters(// Type parameters.
910 // The kind of the rib used for type parameters.
914 /// The rib kind controls the translation of local
915 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
916 #[derive(Copy, Clone, Debug)]
918 /// No translation needs to be applied.
921 /// We passed through a closure scope at the given node ID.
922 /// Translate upvars as appropriate.
923 ClosureRibKind(NodeId /* func id */),
925 /// We passed through an impl or trait and are now in one of its
926 /// methods or associated types. Allow references to ty params that impl or trait
927 /// binds. Disallow any other upvars (including other ty params that are
929 TraitOrImplItemRibKind,
931 /// We passed through an item scope. Disallow upvars.
934 /// We're in a constant item. Can't refer to dynamic stuff.
937 /// We passed through a module.
938 ModuleRibKind(Module<'a>),
940 /// We passed through a `macro_rules!` statement
941 MacroDefinition(DefId),
943 /// All bindings in this rib are type parameters that can't be used
944 /// from the default of a type parameter because they're not declared
945 /// before said type parameter. Also see the `visit_generics` override.
946 ForwardTyParamBanRibKind,
951 /// A rib represents a scope names can live in. Note that these appear in many places, not just
952 /// around braces. At any place where the list of accessible names (of the given namespace)
953 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
954 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
957 /// Different [rib kinds](enum.RibKind) are transparent for different names.
959 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
960 /// resolving, the name is looked up from inside out.
963 bindings: FxHashMap<Ident, Def>,
968 fn new(kind: RibKind<'a>) -> Rib<'a> {
970 bindings: Default::default(),
976 /// An intermediate resolution result.
978 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
979 /// items are visible in their whole block, while defs only from the place they are defined
981 enum LexicalScopeBinding<'a> {
982 Item(&'a NameBinding<'a>),
986 impl<'a> LexicalScopeBinding<'a> {
987 fn item(self) -> Option<&'a NameBinding<'a>> {
989 LexicalScopeBinding::Item(binding) => Some(binding),
994 fn def(self) -> Def {
996 LexicalScopeBinding::Item(binding) => binding.def(),
997 LexicalScopeBinding::Def(def) => def,
1002 #[derive(Copy, Clone, Debug)]
1003 enum ModuleOrUniformRoot<'a> {
1007 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1008 CrateRootAndExternPrelude,
1010 /// Virtual module that denotes resolution in extern prelude.
1011 /// Used for paths starting with `::` on 2018 edition.
1014 /// Virtual module that denotes resolution in current scope.
1015 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1016 /// are always split into two parts, the first of which should be some kind of module.
1020 impl ModuleOrUniformRoot<'_> {
1021 fn same_def(lhs: Self, rhs: Self) -> bool {
1023 (ModuleOrUniformRoot::Module(lhs),
1024 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1025 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1026 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1027 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1028 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1034 #[derive(Clone, Debug)]
1035 enum PathResult<'a> {
1036 Module(ModuleOrUniformRoot<'a>),
1037 NonModule(PathResolution),
1039 Failed(Span, String, bool /* is the error from the last segment? */),
1043 /// An anonymous module, eg. just a block.
1047 /// fn f() {} // (1)
1048 /// { // This is an anonymous module
1049 /// f(); // This resolves to (2) as we are inside the block.
1050 /// fn f() {} // (2)
1052 /// f(); // Resolves to (1)
1056 /// Any module with a name.
1060 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1061 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1066 /// One node in the tree of modules.
1067 pub struct ModuleData<'a> {
1068 parent: Option<Module<'a>>,
1071 // The def id of the closest normal module (`mod`) ancestor (including this module).
1072 normal_ancestor_id: DefId,
1074 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1075 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1076 Option<&'a NameBinding<'a>>)>>,
1077 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1079 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1081 // Macro invocations that can expand into items in this module.
1082 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1084 no_implicit_prelude: bool,
1086 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1087 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1089 // Used to memoize the traits in this module for faster searches through all traits in scope.
1090 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1092 // Whether this module is populated. If not populated, any attempt to
1093 // access the children must be preceded with a
1094 // `populate_module_if_necessary` call.
1095 populated: Cell<bool>,
1097 /// Span of the module itself. Used for error reporting.
1103 type Module<'a> = &'a ModuleData<'a>;
1105 impl<'a> ModuleData<'a> {
1106 fn new(parent: Option<Module<'a>>,
1108 normal_ancestor_id: DefId,
1110 span: Span) -> Self {
1115 resolutions: Default::default(),
1116 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1117 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1118 builtin_attrs: RefCell::new(Vec::new()),
1119 unresolved_invocations: Default::default(),
1120 no_implicit_prelude: false,
1121 glob_importers: RefCell::new(Vec::new()),
1122 globs: RefCell::new(Vec::new()),
1123 traits: RefCell::new(None),
1124 populated: Cell::new(normal_ancestor_id.is_local()),
1130 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1131 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1132 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1136 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1137 let resolutions = self.resolutions.borrow();
1138 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1139 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1140 for &(&(ident, ns), &resolution) in resolutions.iter() {
1141 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1145 fn def(&self) -> Option<Def> {
1147 ModuleKind::Def(def, _) => Some(def),
1152 fn def_id(&self) -> Option<DefId> {
1153 self.def().as_ref().map(Def::def_id)
1156 // `self` resolves to the first module ancestor that `is_normal`.
1157 fn is_normal(&self) -> bool {
1159 ModuleKind::Def(Def::Mod(_), _) => true,
1164 fn is_trait(&self) -> bool {
1166 ModuleKind::Def(Def::Trait(_), _) => true,
1171 fn nearest_item_scope(&'a self) -> Module<'a> {
1172 if self.is_trait() { self.parent.unwrap() } else { self }
1175 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1176 while !ptr::eq(self, other) {
1177 if let Some(parent) = other.parent {
1187 impl<'a> fmt::Debug for ModuleData<'a> {
1188 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1189 write!(f, "{:?}", self.def())
1193 /// Records a possibly-private value, type, or module definition.
1194 #[derive(Clone, Debug)]
1195 pub struct NameBinding<'a> {
1196 kind: NameBindingKind<'a>,
1197 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1200 vis: ty::Visibility,
1203 pub trait ToNameBinding<'a> {
1204 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1207 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1208 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1213 #[derive(Clone, Debug)]
1214 enum NameBindingKind<'a> {
1215 Def(Def, /* is_macro_export */ bool),
1218 binding: &'a NameBinding<'a>,
1219 directive: &'a ImportDirective<'a>,
1224 impl<'a> NameBindingKind<'a> {
1225 /// Is this a name binding of a import?
1226 fn is_import(&self) -> bool {
1228 NameBindingKind::Import { .. } => true,
1234 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1236 struct UseError<'a> {
1237 err: DiagnosticBuilder<'a>,
1238 /// Attach `use` statements for these candidates
1239 candidates: Vec<ImportSuggestion>,
1240 /// The node id of the module to place the use statements in
1242 /// Whether the diagnostic should state that it's "better"
1246 #[derive(Clone, Copy, PartialEq, Debug)]
1247 enum AmbiguityKind {
1252 LegacyHelperVsPrelude,
1257 MoreExpandedVsOuter,
1260 impl AmbiguityKind {
1261 fn descr(self) -> &'static str {
1263 AmbiguityKind::Import =>
1264 "name vs any other name during import resolution",
1265 AmbiguityKind::AbsolutePath =>
1266 "name in the crate root vs extern crate during absolute path resolution",
1267 AmbiguityKind::BuiltinAttr =>
1268 "built-in attribute vs any other name",
1269 AmbiguityKind::DeriveHelper =>
1270 "derive helper attribute vs any other name",
1271 AmbiguityKind::LegacyHelperVsPrelude =>
1272 "legacy plugin helper attribute vs name from prelude",
1273 AmbiguityKind::LegacyVsModern =>
1274 "`macro_rules` vs non-`macro_rules` from other module",
1275 AmbiguityKind::GlobVsOuter =>
1276 "glob import vs any other name from outer scope during import/macro resolution",
1277 AmbiguityKind::GlobVsGlob =>
1278 "glob import vs glob import in the same module",
1279 AmbiguityKind::GlobVsExpanded =>
1280 "glob import vs macro-expanded name in the same \
1281 module during import/macro resolution",
1282 AmbiguityKind::MoreExpandedVsOuter =>
1283 "macro-expanded name vs less macro-expanded name \
1284 from outer scope during import/macro resolution",
1289 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1290 #[derive(Clone, Copy, PartialEq)]
1291 enum AmbiguityErrorMisc {
1298 struct AmbiguityError<'a> {
1299 kind: AmbiguityKind,
1301 b1: &'a NameBinding<'a>,
1302 b2: &'a NameBinding<'a>,
1303 misc1: AmbiguityErrorMisc,
1304 misc2: AmbiguityErrorMisc,
1307 impl<'a> NameBinding<'a> {
1308 fn module(&self) -> Option<Module<'a>> {
1310 NameBindingKind::Module(module) => Some(module),
1311 NameBindingKind::Import { binding, .. } => binding.module(),
1316 fn def(&self) -> Def {
1318 NameBindingKind::Def(def, _) => def,
1319 NameBindingKind::Module(module) => module.def().unwrap(),
1320 NameBindingKind::Import { binding, .. } => binding.def(),
1324 fn is_ambiguity(&self) -> bool {
1325 self.ambiguity.is_some() || match self.kind {
1326 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1331 // We sometimes need to treat variants as `pub` for backwards compatibility
1332 fn pseudo_vis(&self) -> ty::Visibility {
1333 if self.is_variant() && self.def().def_id().is_local() {
1334 ty::Visibility::Public
1340 fn is_variant(&self) -> bool {
1342 NameBindingKind::Def(Def::Variant(..), _) |
1343 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1348 fn is_extern_crate(&self) -> bool {
1350 NameBindingKind::Import {
1351 directive: &ImportDirective {
1352 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1355 NameBindingKind::Module(
1356 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1357 ) => def_id.index == CRATE_DEF_INDEX,
1362 fn is_import(&self) -> bool {
1364 NameBindingKind::Import { .. } => true,
1369 fn is_glob_import(&self) -> bool {
1371 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1376 fn is_importable(&self) -> bool {
1378 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1383 fn is_macro_def(&self) -> bool {
1385 NameBindingKind::Def(Def::Macro(..), _) => true,
1390 fn macro_kind(&self) -> Option<MacroKind> {
1392 Def::Macro(_, kind) => Some(kind),
1393 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1398 fn descr(&self) -> &'static str {
1399 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1402 fn article(&self) -> &'static str {
1403 if self.is_extern_crate() { "an" } else { self.def().article() }
1406 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1407 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1408 // Then this function returns `true` if `self` may emerge from a macro *after* that
1409 // in some later round and screw up our previously found resolution.
1410 // See more detailed explanation in
1411 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1412 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1413 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1414 // Expansions are partially ordered, so "may appear after" is an inversion of
1415 // "certainly appears before or simultaneously" and includes unordered cases.
1416 let self_parent_expansion = self.expansion;
1417 let other_parent_expansion = binding.expansion;
1418 let certainly_before_other_or_simultaneously =
1419 other_parent_expansion.is_descendant_of(self_parent_expansion);
1420 let certainly_before_invoc_or_simultaneously =
1421 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1422 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1426 /// Interns the names of the primitive types.
1428 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1429 /// special handling, since they have no place of origin.
1431 struct PrimitiveTypeTable {
1432 primitive_types: FxHashMap<Name, PrimTy>,
1435 impl PrimitiveTypeTable {
1436 fn new() -> PrimitiveTypeTable {
1437 let mut table = PrimitiveTypeTable::default();
1439 table.intern("bool", Bool);
1440 table.intern("char", Char);
1441 table.intern("f32", Float(FloatTy::F32));
1442 table.intern("f64", Float(FloatTy::F64));
1443 table.intern("isize", Int(IntTy::Isize));
1444 table.intern("i8", Int(IntTy::I8));
1445 table.intern("i16", Int(IntTy::I16));
1446 table.intern("i32", Int(IntTy::I32));
1447 table.intern("i64", Int(IntTy::I64));
1448 table.intern("i128", Int(IntTy::I128));
1449 table.intern("str", Str);
1450 table.intern("usize", Uint(UintTy::Usize));
1451 table.intern("u8", Uint(UintTy::U8));
1452 table.intern("u16", Uint(UintTy::U16));
1453 table.intern("u32", Uint(UintTy::U32));
1454 table.intern("u64", Uint(UintTy::U64));
1455 table.intern("u128", Uint(UintTy::U128));
1459 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1460 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1464 #[derive(Debug, Default, Clone)]
1465 pub struct ExternPreludeEntry<'a> {
1466 extern_crate_item: Option<&'a NameBinding<'a>>,
1467 pub introduced_by_item: bool,
1470 /// The main resolver class.
1472 /// This is the visitor that walks the whole crate.
1473 pub struct Resolver<'a> {
1474 session: &'a Session,
1477 pub definitions: Definitions,
1479 graph_root: Module<'a>,
1481 prelude: Option<Module<'a>>,
1482 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1484 /// n.b. This is used only for better diagnostics, not name resolution itself.
1485 has_self: FxHashSet<DefId>,
1487 /// Names of fields of an item `DefId` accessible with dot syntax.
1488 /// Used for hints during error reporting.
1489 field_names: FxHashMap<DefId, Vec<Name>>,
1491 /// All imports known to succeed or fail.
1492 determined_imports: Vec<&'a ImportDirective<'a>>,
1494 /// All non-determined imports.
1495 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1497 /// The module that represents the current item scope.
1498 current_module: Module<'a>,
1500 /// The current set of local scopes for types and values.
1501 /// FIXME #4948: Reuse ribs to avoid allocation.
1502 ribs: PerNS<Vec<Rib<'a>>>,
1504 /// The current set of local scopes, for labels.
1505 label_ribs: Vec<Rib<'a>>,
1507 /// The trait that the current context can refer to.
1508 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1510 /// The current self type if inside an impl (used for better errors).
1511 current_self_type: Option<Ty>,
1513 /// The current self item if inside an ADT (used for better errors).
1514 current_self_item: Option<NodeId>,
1516 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1517 /// We are resolving a last import segment during import validation.
1518 last_import_segment: bool,
1519 /// This binding should be ignored during in-module resolution, so that we don't get
1520 /// "self-confirming" import resolutions during import validation.
1521 blacklisted_binding: Option<&'a NameBinding<'a>>,
1523 /// The idents for the primitive types.
1524 primitive_type_table: PrimitiveTypeTable,
1527 import_map: ImportMap,
1528 pub freevars: FreevarMap,
1529 freevars_seen: NodeMap<NodeMap<usize>>,
1530 pub export_map: ExportMap,
1531 pub trait_map: TraitMap,
1533 /// A map from nodes to anonymous modules.
1534 /// Anonymous modules are pseudo-modules that are implicitly created around items
1535 /// contained within blocks.
1537 /// For example, if we have this:
1545 /// There will be an anonymous module created around `g` with the ID of the
1546 /// entry block for `f`.
1547 block_map: NodeMap<Module<'a>>,
1548 module_map: FxHashMap<DefId, Module<'a>>,
1549 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1550 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1552 /// Maps glob imports to the names of items actually imported.
1553 pub glob_map: GlobMap,
1555 used_imports: FxHashSet<(NodeId, Namespace)>,
1556 pub maybe_unused_trait_imports: NodeSet,
1557 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1559 /// A list of labels as of yet unused. Labels will be removed from this map when
1560 /// they are used (in a `break` or `continue` statement)
1561 pub unused_labels: FxHashMap<NodeId, Span>,
1563 /// privacy errors are delayed until the end in order to deduplicate them
1564 privacy_errors: Vec<PrivacyError<'a>>,
1565 /// ambiguity errors are delayed for deduplication
1566 ambiguity_errors: Vec<AmbiguityError<'a>>,
1567 /// `use` injections are delayed for better placement and deduplication
1568 use_injections: Vec<UseError<'a>>,
1569 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1570 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1572 arenas: &'a ResolverArenas<'a>,
1573 dummy_binding: &'a NameBinding<'a>,
1575 crate_loader: &'a mut CrateLoader<'a>,
1576 macro_names: FxHashSet<Ident>,
1577 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1578 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1579 pub all_macros: FxHashMap<Name, Def>,
1580 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1581 macro_defs: FxHashMap<Mark, DefId>,
1582 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1584 /// List of crate local macros that we need to warn about as being unused.
1585 /// Right now this only includes macro_rules! macros, and macros 2.0.
1586 unused_macros: FxHashSet<DefId>,
1588 /// Maps the `Mark` of an expansion to its containing module or block.
1589 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1591 /// Avoid duplicated errors for "name already defined".
1592 name_already_seen: FxHashMap<Name, Span>,
1594 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1596 /// This table maps struct IDs into struct constructor IDs,
1597 /// it's not used during normal resolution, only for better error reporting.
1598 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1600 /// Only used for better errors on `fn(): fn()`
1601 current_type_ascription: Vec<Span>,
1603 injected_crate: Option<Module<'a>>,
1606 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1608 pub struct ResolverArenas<'a> {
1609 modules: arena::TypedArena<ModuleData<'a>>,
1610 local_modules: RefCell<Vec<Module<'a>>>,
1611 name_bindings: arena::TypedArena<NameBinding<'a>>,
1612 import_directives: arena::TypedArena<ImportDirective<'a>>,
1613 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1614 invocation_data: arena::TypedArena<InvocationData<'a>>,
1615 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1618 impl<'a> ResolverArenas<'a> {
1619 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1620 let module = self.modules.alloc(module);
1621 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1622 self.local_modules.borrow_mut().push(module);
1626 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1627 self.local_modules.borrow()
1629 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1630 self.name_bindings.alloc(name_binding)
1632 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1633 -> &'a ImportDirective<'_> {
1634 self.import_directives.alloc(import_directive)
1636 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1637 self.name_resolutions.alloc(Default::default())
1639 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1640 -> &'a InvocationData<'a> {
1641 self.invocation_data.alloc(expansion_data)
1643 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1644 self.legacy_bindings.alloc(binding)
1648 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1649 fn parent(self, id: DefId) -> Option<DefId> {
1651 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1652 _ => self.cstore.def_key(id).parent,
1653 }.map(|index| DefId { index, ..id })
1657 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1658 /// the resolver is no longer needed as all the relevant information is inline.
1659 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1660 fn resolve_hir_path(
1665 self.resolve_hir_path_cb(path, is_value,
1666 |resolver, span, error| resolve_error(resolver, span, error))
1669 fn resolve_str_path(
1672 crate_root: Option<&str>,
1673 components: &[&str],
1676 let segments = iter::once(keywords::PathRoot.ident())
1678 crate_root.into_iter()
1679 .chain(components.iter().cloned())
1680 .map(Ident::from_str)
1681 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1684 let path = ast::Path {
1689 self.resolve_hir_path(&path, is_value)
1692 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1693 self.def_map.get(&id).cloned()
1696 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1697 self.import_map.get(&id).cloned().unwrap_or_default()
1700 fn definitions(&mut self) -> &mut Definitions {
1701 &mut self.definitions
1705 impl<'a> Resolver<'a> {
1706 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1707 /// isn't something that can be returned because it can't be made to live that long,
1708 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1709 /// just that an error occurred.
1710 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1711 -> Result<hir::Path, ()> {
1713 let mut errored = false;
1715 let path = if path_str.starts_with("::") {
1718 segments: iter::once(keywords::PathRoot.ident())
1720 path_str.split("::").skip(1).map(Ident::from_str)
1722 .map(|i| self.new_ast_path_segment(i))
1730 .map(Ident::from_str)
1731 .map(|i| self.new_ast_path_segment(i))
1735 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1736 if errored || path.def == Def::Err {
1743 /// resolve_hir_path, but takes a callback in case there was an error
1744 fn resolve_hir_path_cb<F>(
1750 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1752 let namespace = if is_value { ValueNS } else { TypeNS };
1753 let span = path.span;
1754 let segments = &path.segments;
1755 let path = Segment::from_path(&path);
1756 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1757 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1758 span, CrateLint::No) {
1759 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1760 module.def().unwrap(),
1761 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1762 path_res.base_def(),
1763 PathResult::NonModule(..) => {
1764 let msg = "type-relative paths are not supported in this context";
1765 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1768 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1769 PathResult::Failed(span, msg, _) => {
1770 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1775 let segments: Vec<_> = segments.iter().map(|seg| {
1776 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1777 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1783 segments: segments.into(),
1787 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1788 let mut seg = ast::PathSegment::from_ident(ident);
1789 seg.id = self.session.next_node_id();
1794 impl<'a> Resolver<'a> {
1795 pub fn new(session: &'a Session,
1799 crate_loader: &'a mut CrateLoader<'a>,
1800 arenas: &'a ResolverArenas<'a>)
1802 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1803 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1804 let graph_root = arenas.alloc_module(ModuleData {
1805 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1806 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1808 let mut module_map = FxHashMap::default();
1809 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1811 let mut definitions = Definitions::new();
1812 DefCollector::new(&mut definitions, Mark::root())
1813 .collect_root(crate_name, session.local_crate_disambiguator());
1815 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1816 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1819 if !attr::contains_name(&krate.attrs, "no_core") {
1820 extern_prelude.insert(Ident::from_str("core"), Default::default());
1821 if !attr::contains_name(&krate.attrs, "no_std") {
1822 extern_prelude.insert(Ident::from_str("std"), Default::default());
1823 if session.rust_2018() {
1824 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1829 let mut invocations = FxHashMap::default();
1830 invocations.insert(Mark::root(),
1831 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1833 let mut macro_defs = FxHashMap::default();
1834 macro_defs.insert(Mark::root(), root_def_id);
1843 // The outermost module has def ID 0; this is not reflected in the
1849 has_self: FxHashSet::default(),
1850 field_names: FxHashMap::default(),
1852 determined_imports: Vec::new(),
1853 indeterminate_imports: Vec::new(),
1855 current_module: graph_root,
1857 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1858 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1859 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1861 label_ribs: Vec::new(),
1863 current_trait_ref: None,
1864 current_self_type: None,
1865 current_self_item: None,
1866 last_import_segment: false,
1867 blacklisted_binding: None,
1869 primitive_type_table: PrimitiveTypeTable::new(),
1871 def_map: Default::default(),
1872 import_map: Default::default(),
1873 freevars: Default::default(),
1874 freevars_seen: Default::default(),
1875 export_map: FxHashMap::default(),
1876 trait_map: Default::default(),
1878 block_map: Default::default(),
1879 extern_module_map: FxHashMap::default(),
1880 binding_parent_modules: FxHashMap::default(),
1882 glob_map: Default::default(),
1884 used_imports: FxHashSet::default(),
1885 maybe_unused_trait_imports: Default::default(),
1886 maybe_unused_extern_crates: Vec::new(),
1888 unused_labels: FxHashMap::default(),
1890 privacy_errors: Vec::new(),
1891 ambiguity_errors: Vec::new(),
1892 use_injections: Vec::new(),
1893 macro_expanded_macro_export_errors: BTreeSet::new(),
1896 dummy_binding: arenas.alloc_name_binding(NameBinding {
1897 kind: NameBindingKind::Def(Def::Err, false),
1899 expansion: Mark::root(),
1901 vis: ty::Visibility::Public,
1905 macro_names: FxHashSet::default(),
1906 builtin_macros: FxHashMap::default(),
1907 macro_use_prelude: FxHashMap::default(),
1908 all_macros: FxHashMap::default(),
1909 macro_map: FxHashMap::default(),
1912 local_macro_def_scopes: FxHashMap::default(),
1913 name_already_seen: FxHashMap::default(),
1914 potentially_unused_imports: Vec::new(),
1915 struct_constructors: Default::default(),
1916 unused_macros: FxHashSet::default(),
1917 current_type_ascription: Vec::new(),
1918 injected_crate: None,
1922 pub fn arenas() -> ResolverArenas<'a> {
1926 /// Runs the function on each namespace.
1927 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1933 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1935 match self.macro_defs.get(&ctxt.outer()) {
1936 Some(&def_id) => return def_id,
1937 None => ctxt.remove_mark(),
1942 /// Entry point to crate resolution.
1943 pub fn resolve_crate(&mut self, krate: &Crate) {
1944 ImportResolver { resolver: self }.finalize_imports();
1945 self.current_module = self.graph_root;
1946 self.finalize_current_module_macro_resolutions();
1948 visit::walk_crate(self, krate);
1950 check_unused::check_crate(self, krate);
1951 self.report_errors(krate);
1952 self.crate_loader.postprocess(krate);
1959 normal_ancestor_id: DefId,
1963 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1964 self.arenas.alloc_module(module)
1967 fn record_use(&mut self, ident: Ident, ns: Namespace,
1968 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1969 if let Some((b2, kind)) = used_binding.ambiguity {
1970 self.ambiguity_errors.push(AmbiguityError {
1971 kind, ident, b1: used_binding, b2,
1972 misc1: AmbiguityErrorMisc::None,
1973 misc2: AmbiguityErrorMisc::None,
1976 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1977 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1978 // but not introduce it, as used if they are accessed from lexical scope.
1979 if is_lexical_scope {
1980 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1981 if let Some(crate_item) = entry.extern_crate_item {
1982 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1989 directive.used.set(true);
1990 self.used_imports.insert((directive.id, ns));
1991 self.add_to_glob_map(&directive, ident);
1992 self.record_use(ident, ns, binding, false);
1997 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
1998 if directive.is_glob() {
1999 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2003 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2004 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2005 /// `ident` in the first scope that defines it (or None if no scopes define it).
2007 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2008 /// the items are defined in the block. For example,
2011 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2014 /// g(); // This resolves to the local variable `g` since it shadows the item.
2018 /// Invariant: This must only be called during main resolution, not during
2019 /// import resolution.
2020 fn resolve_ident_in_lexical_scope(&mut self,
2023 record_used_id: Option<NodeId>,
2025 -> Option<LexicalScopeBinding<'a>> {
2026 assert!(ns == TypeNS || ns == ValueNS);
2027 if ident.name == keywords::Invalid.name() {
2028 return Some(LexicalScopeBinding::Def(Def::Err));
2030 ident.span = if ident.name == keywords::SelfUpper.name() {
2031 // FIXME(jseyfried) improve `Self` hygiene
2032 ident.span.with_ctxt(SyntaxContext::empty())
2033 } else if ns == TypeNS {
2036 ident.span.modern_and_legacy()
2039 // Walk backwards up the ribs in scope.
2040 let record_used = record_used_id.is_some();
2041 let mut module = self.graph_root;
2042 for i in (0 .. self.ribs[ns].len()).rev() {
2043 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2044 // The ident resolves to a type parameter or local variable.
2045 return Some(LexicalScopeBinding::Def(
2046 self.adjust_local_def(ns, i, def, record_used, path_span)
2050 module = match self.ribs[ns][i].kind {
2051 ModuleRibKind(module) => module,
2052 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2053 // If an invocation of this macro created `ident`, give up on `ident`
2054 // and switch to `ident`'s source from the macro definition.
2055 ident.span.remove_mark();
2061 let item = self.resolve_ident_in_module_unadjusted(
2062 ModuleOrUniformRoot::Module(module),
2068 if let Ok(binding) = item {
2069 // The ident resolves to an item.
2070 return Some(LexicalScopeBinding::Item(binding));
2074 ModuleKind::Block(..) => {}, // We can see through blocks
2079 ident.span = ident.span.modern();
2080 let mut poisoned = None;
2082 let opt_module = if let Some(node_id) = record_used_id {
2083 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2084 node_id, &mut poisoned)
2086 self.hygienic_lexical_parent(module, &mut ident.span)
2088 module = unwrap_or!(opt_module, break);
2089 let orig_current_module = self.current_module;
2090 self.current_module = module; // Lexical resolutions can never be a privacy error.
2091 let result = self.resolve_ident_in_module_unadjusted(
2092 ModuleOrUniformRoot::Module(module),
2098 self.current_module = orig_current_module;
2102 if let Some(node_id) = poisoned {
2103 self.session.buffer_lint_with_diagnostic(
2104 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2105 node_id, ident.span,
2106 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2107 lint::builtin::BuiltinLintDiagnostics::
2108 ProcMacroDeriveResolutionFallback(ident.span),
2111 return Some(LexicalScopeBinding::Item(binding))
2113 Err(Determined) => continue,
2114 Err(Undetermined) =>
2115 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2119 if !module.no_implicit_prelude {
2121 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2122 return Some(LexicalScopeBinding::Item(binding));
2125 if ns == TypeNS && is_known_tool(ident.name) {
2126 let binding = (Def::ToolMod, ty::Visibility::Public,
2127 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2128 return Some(LexicalScopeBinding::Item(binding));
2130 if let Some(prelude) = self.prelude {
2131 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2132 ModuleOrUniformRoot::Module(prelude),
2138 return Some(LexicalScopeBinding::Item(binding));
2146 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2147 -> Option<Module<'a>> {
2148 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2149 return Some(self.macro_def_scope(span.remove_mark()));
2152 if let ModuleKind::Block(..) = module.kind {
2153 return Some(module.parent.unwrap());
2159 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2160 span: &mut Span, node_id: NodeId,
2161 poisoned: &mut Option<NodeId>)
2162 -> Option<Module<'a>> {
2163 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2167 // We need to support the next case under a deprecation warning
2170 // ---- begin: this comes from a proc macro derive
2171 // mod implementation_details {
2172 // // Note that `MyStruct` is not in scope here.
2173 // impl SomeTrait for MyStruct { ... }
2177 // So we have to fall back to the module's parent during lexical resolution in this case.
2178 if let Some(parent) = module.parent {
2179 // Inner module is inside the macro, parent module is outside of the macro.
2180 if module.expansion != parent.expansion &&
2181 module.expansion.is_descendant_of(parent.expansion) {
2182 // The macro is a proc macro derive
2183 if module.expansion.looks_like_proc_macro_derive() {
2184 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2185 *poisoned = Some(node_id);
2186 return module.parent;
2195 fn resolve_ident_in_module(
2197 module: ModuleOrUniformRoot<'a>,
2200 parent_scope: Option<&ParentScope<'a>>,
2203 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2204 self.resolve_ident_in_module_ext(
2205 module, ident, ns, parent_scope, record_used, path_span
2206 ).map_err(|(determinacy, _)| determinacy)
2209 fn resolve_ident_in_module_ext(
2211 module: ModuleOrUniformRoot<'a>,
2214 parent_scope: Option<&ParentScope<'a>>,
2217 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2218 let orig_current_module = self.current_module;
2220 ModuleOrUniformRoot::Module(module) => {
2221 ident.span = ident.span.modern();
2222 if let Some(def) = ident.span.adjust(module.expansion) {
2223 self.current_module = self.macro_def_scope(def);
2226 ModuleOrUniformRoot::ExternPrelude => {
2227 ident.span = ident.span.modern();
2228 ident.span.adjust(Mark::root());
2230 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2231 ModuleOrUniformRoot::CurrentScope => {
2235 let result = self.resolve_ident_in_module_unadjusted_ext(
2236 module, ident, ns, parent_scope, false, record_used, path_span,
2238 self.current_module = orig_current_module;
2242 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2243 let mut ctxt = ident.span.ctxt();
2244 let mark = if ident.name == keywords::DollarCrate.name() {
2245 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2246 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2247 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2248 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2249 // definitions actually produced by `macro` and `macro` definitions produced by
2250 // `macro_rules!`, but at least such configurations are not stable yet.
2251 ctxt = ctxt.modern_and_legacy();
2252 let mut iter = ctxt.marks().into_iter().rev().peekable();
2253 let mut result = None;
2254 // Find the last modern mark from the end if it exists.
2255 while let Some(&(mark, transparency)) = iter.peek() {
2256 if transparency == Transparency::Opaque {
2257 result = Some(mark);
2263 // Then find the last legacy mark from the end if it exists.
2264 for (mark, transparency) in iter {
2265 if transparency == Transparency::SemiTransparent {
2266 result = Some(mark);
2273 ctxt = ctxt.modern();
2274 ctxt.adjust(Mark::root())
2276 let module = match mark {
2277 Some(def) => self.macro_def_scope(def),
2278 None => return self.graph_root,
2280 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2283 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2284 let mut module = self.get_module(module.normal_ancestor_id);
2285 while module.span.ctxt().modern() != *ctxt {
2286 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2287 module = self.get_module(parent.normal_ancestor_id);
2294 // We maintain a list of value ribs and type ribs.
2296 // Simultaneously, we keep track of the current position in the module
2297 // graph in the `current_module` pointer. When we go to resolve a name in
2298 // the value or type namespaces, we first look through all the ribs and
2299 // then query the module graph. When we resolve a name in the module
2300 // namespace, we can skip all the ribs (since nested modules are not
2301 // allowed within blocks in Rust) and jump straight to the current module
2304 // Named implementations are handled separately. When we find a method
2305 // call, we consult the module node to find all of the implementations in
2306 // scope. This information is lazily cached in the module node. We then
2307 // generate a fake "implementation scope" containing all the
2308 // implementations thus found, for compatibility with old resolve pass.
2310 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2311 where F: FnOnce(&mut Resolver<'_>) -> T
2313 let id = self.definitions.local_def_id(id);
2314 let module = self.module_map.get(&id).cloned(); // clones a reference
2315 if let Some(module) = module {
2316 // Move down in the graph.
2317 let orig_module = replace(&mut self.current_module, module);
2318 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2319 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2321 self.finalize_current_module_macro_resolutions();
2324 self.current_module = orig_module;
2325 self.ribs[ValueNS].pop();
2326 self.ribs[TypeNS].pop();
2333 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2334 /// is returned by the given predicate function
2336 /// Stops after meeting a closure.
2337 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2338 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2340 for rib in self.label_ribs.iter().rev() {
2343 // If an invocation of this macro created `ident`, give up on `ident`
2344 // and switch to `ident`'s source from the macro definition.
2345 MacroDefinition(def) => {
2346 if def == self.macro_def(ident.span.ctxt()) {
2347 ident.span.remove_mark();
2351 // Do not resolve labels across function boundary
2355 let r = pred(rib, ident);
2363 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2364 self.with_current_self_item(item, |this| {
2365 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2366 let item_def_id = this.definitions.local_def_id(item.id);
2367 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2368 visit::walk_item(this, item);
2374 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2375 let segments = &use_tree.prefix.segments;
2376 if !segments.is_empty() {
2377 let ident = segments[0].ident;
2378 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2382 let nss = match use_tree.kind {
2383 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2386 let report_error = |this: &Self, ns| {
2387 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2388 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2392 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2393 Some(LexicalScopeBinding::Def(..)) => {
2394 report_error(self, ns);
2396 Some(LexicalScopeBinding::Item(binding)) => {
2397 let orig_blacklisted_binding =
2398 mem::replace(&mut self.blacklisted_binding, Some(binding));
2399 if let Some(LexicalScopeBinding::Def(..)) =
2400 self.resolve_ident_in_lexical_scope(ident, ns, None,
2401 use_tree.prefix.span) {
2402 report_error(self, ns);
2404 self.blacklisted_binding = orig_blacklisted_binding;
2409 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2410 for (use_tree, _) in use_trees {
2411 self.future_proof_import(use_tree);
2416 fn resolve_item(&mut self, item: &Item) {
2417 let name = item.ident.name;
2418 debug!("(resolving item) resolving {}", name);
2421 ItemKind::Ty(_, ref generics) |
2422 ItemKind::Fn(_, _, ref generics, _) |
2423 ItemKind::Existential(_, ref generics) => {
2424 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2425 |this| visit::walk_item(this, item));
2428 ItemKind::Enum(_, ref generics) |
2429 ItemKind::Struct(_, ref generics) |
2430 ItemKind::Union(_, ref generics) => {
2431 self.resolve_adt(item, generics);
2434 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2435 self.resolve_implementation(generics,
2441 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2442 // Create a new rib for the trait-wide type parameters.
2443 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2444 let local_def_id = this.definitions.local_def_id(item.id);
2445 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2446 this.visit_generics(generics);
2447 walk_list!(this, visit_param_bound, bounds);
2449 for trait_item in trait_items {
2450 let type_parameters = HasTypeParameters(&trait_item.generics,
2451 TraitOrImplItemRibKind);
2452 this.with_type_parameter_rib(type_parameters, |this| {
2453 match trait_item.node {
2454 TraitItemKind::Const(ref ty, ref default) => {
2457 // Only impose the restrictions of
2458 // ConstRibKind for an actual constant
2459 // expression in a provided default.
2460 if let Some(ref expr) = *default{
2461 this.with_constant_rib(|this| {
2462 this.visit_expr(expr);
2466 TraitItemKind::Method(_, _) => {
2467 visit::walk_trait_item(this, trait_item)
2469 TraitItemKind::Type(..) => {
2470 visit::walk_trait_item(this, trait_item)
2472 TraitItemKind::Macro(_) => {
2473 panic!("unexpanded macro in resolve!")
2482 ItemKind::TraitAlias(ref generics, ref bounds) => {
2483 // Create a new rib for the trait-wide type parameters.
2484 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2485 let local_def_id = this.definitions.local_def_id(item.id);
2486 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2487 this.visit_generics(generics);
2488 walk_list!(this, visit_param_bound, bounds);
2493 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2494 self.with_scope(item.id, |this| {
2495 visit::walk_item(this, item);
2499 ItemKind::Static(ref ty, _, ref expr) |
2500 ItemKind::Const(ref ty, ref expr) => {
2501 self.with_item_rib(|this| {
2503 this.with_constant_rib(|this| {
2504 this.visit_expr(expr);
2509 ItemKind::Use(ref use_tree) => {
2510 self.future_proof_import(use_tree);
2513 ItemKind::ExternCrate(..) |
2514 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2515 // do nothing, these are just around to be encoded
2518 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2522 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2523 where F: FnOnce(&mut Resolver<'_>)
2525 match type_parameters {
2526 HasTypeParameters(generics, rib_kind) => {
2527 let mut function_type_rib = Rib::new(rib_kind);
2528 let mut seen_bindings = FxHashMap::default();
2529 for param in &generics.params {
2531 GenericParamKind::Lifetime { .. } => {}
2532 GenericParamKind::Type { .. } => {
2533 let ident = param.ident.modern();
2534 debug!("with_type_parameter_rib: {}", param.id);
2536 if seen_bindings.contains_key(&ident) {
2537 let span = seen_bindings.get(&ident).unwrap();
2538 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2542 resolve_error(self, param.ident.span, err);
2544 seen_bindings.entry(ident).or_insert(param.ident.span);
2546 // Plain insert (no renaming).
2547 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2548 function_type_rib.bindings.insert(ident, def);
2549 self.record_def(param.id, PathResolution::new(def));
2553 self.ribs[TypeNS].push(function_type_rib);
2556 NoTypeParameters => {
2563 if let HasTypeParameters(..) = type_parameters {
2564 self.ribs[TypeNS].pop();
2568 fn with_label_rib<F>(&mut self, f: F)
2569 where F: FnOnce(&mut Resolver<'_>)
2571 self.label_ribs.push(Rib::new(NormalRibKind));
2573 self.label_ribs.pop();
2576 fn with_item_rib<F>(&mut self, f: F)
2577 where F: FnOnce(&mut Resolver<'_>)
2579 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2580 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2582 self.ribs[TypeNS].pop();
2583 self.ribs[ValueNS].pop();
2586 fn with_constant_rib<F>(&mut self, f: F)
2587 where F: FnOnce(&mut Resolver<'_>)
2589 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2590 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2592 self.label_ribs.pop();
2593 self.ribs[ValueNS].pop();
2596 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2597 where F: FnOnce(&mut Resolver<'_>) -> T
2599 // Handle nested impls (inside fn bodies)
2600 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2601 let result = f(self);
2602 self.current_self_type = previous_value;
2606 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2607 where F: FnOnce(&mut Resolver<'_>) -> T
2609 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2610 let result = f(self);
2611 self.current_self_item = previous_value;
2615 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2616 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2617 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2619 let mut new_val = None;
2620 let mut new_id = None;
2621 if let Some(trait_ref) = opt_trait_ref {
2622 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2623 let def = self.smart_resolve_path_fragment(
2627 trait_ref.path.span,
2628 PathSource::Trait(AliasPossibility::No),
2629 CrateLint::SimplePath(trait_ref.ref_id),
2631 if def != Def::Err {
2632 new_id = Some(def.def_id());
2633 let span = trait_ref.path.span;
2634 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2635 self.resolve_path_without_parent_scope(
2640 CrateLint::SimplePath(trait_ref.ref_id),
2643 new_val = Some((module, trait_ref.clone()));
2647 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2648 let result = f(self, new_id);
2649 self.current_trait_ref = original_trait_ref;
2653 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2654 where F: FnOnce(&mut Resolver<'_>)
2656 let mut self_type_rib = Rib::new(NormalRibKind);
2658 // plain insert (no renaming, types are not currently hygienic....)
2659 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2660 self.ribs[TypeNS].push(self_type_rib);
2662 self.ribs[TypeNS].pop();
2665 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2666 where F: FnOnce(&mut Resolver<'_>)
2668 let self_def = Def::SelfCtor(impl_id);
2669 let mut self_type_rib = Rib::new(NormalRibKind);
2670 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2671 self.ribs[ValueNS].push(self_type_rib);
2673 self.ribs[ValueNS].pop();
2676 fn resolve_implementation(&mut self,
2677 generics: &Generics,
2678 opt_trait_reference: &Option<TraitRef>,
2681 impl_items: &[ImplItem]) {
2682 // If applicable, create a rib for the type parameters.
2683 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2684 // Dummy self type for better errors if `Self` is used in the trait path.
2685 this.with_self_rib(Def::SelfTy(None, None), |this| {
2686 // Resolve the trait reference, if necessary.
2687 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2688 let item_def_id = this.definitions.local_def_id(item_id);
2689 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2690 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2691 // Resolve type arguments in the trait path.
2692 visit::walk_trait_ref(this, trait_ref);
2694 // Resolve the self type.
2695 this.visit_ty(self_type);
2696 // Resolve the type parameters.
2697 this.visit_generics(generics);
2698 // Resolve the items within the impl.
2699 this.with_current_self_type(self_type, |this| {
2700 this.with_self_struct_ctor_rib(item_def_id, |this| {
2701 for impl_item in impl_items {
2702 this.resolve_visibility(&impl_item.vis);
2704 // We also need a new scope for the impl item type parameters.
2705 let type_parameters = HasTypeParameters(&impl_item.generics,
2706 TraitOrImplItemRibKind);
2707 this.with_type_parameter_rib(type_parameters, |this| {
2708 use self::ResolutionError::*;
2709 match impl_item.node {
2710 ImplItemKind::Const(..) => {
2711 // If this is a trait impl, ensure the const
2713 this.check_trait_item(impl_item.ident,
2716 |n, s| ConstNotMemberOfTrait(n, s));
2717 this.with_constant_rib(|this|
2718 visit::walk_impl_item(this, impl_item)
2721 ImplItemKind::Method(..) => {
2722 // If this is a trait impl, ensure the method
2724 this.check_trait_item(impl_item.ident,
2727 |n, s| MethodNotMemberOfTrait(n, s));
2729 visit::walk_impl_item(this, impl_item);
2731 ImplItemKind::Type(ref ty) => {
2732 // If this is a trait impl, ensure the type
2734 this.check_trait_item(impl_item.ident,
2737 |n, s| TypeNotMemberOfTrait(n, s));
2741 ImplItemKind::Existential(ref bounds) => {
2742 // If this is a trait impl, ensure the type
2744 this.check_trait_item(impl_item.ident,
2747 |n, s| TypeNotMemberOfTrait(n, s));
2749 for bound in bounds {
2750 this.visit_param_bound(bound);
2753 ImplItemKind::Macro(_) =>
2754 panic!("unexpanded macro in resolve!"),
2766 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2767 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2769 // If there is a TraitRef in scope for an impl, then the method must be in the
2771 if let Some((module, _)) = self.current_trait_ref {
2772 if self.resolve_ident_in_module(
2773 ModuleOrUniformRoot::Module(module),
2780 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2781 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2786 fn resolve_local(&mut self, local: &Local) {
2787 // Resolve the type.
2788 walk_list!(self, visit_ty, &local.ty);
2790 // Resolve the initializer.
2791 walk_list!(self, visit_expr, &local.init);
2793 // Resolve the pattern.
2794 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2797 // build a map from pattern identifiers to binding-info's.
2798 // this is done hygienically. This could arise for a macro
2799 // that expands into an or-pattern where one 'x' was from the
2800 // user and one 'x' came from the macro.
2801 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2802 let mut binding_map = FxHashMap::default();
2804 pat.walk(&mut |pat| {
2805 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2806 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2807 Some(Def::Local(..)) => true,
2810 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2811 binding_map.insert(ident, binding_info);
2820 // check that all of the arms in an or-pattern have exactly the
2821 // same set of bindings, with the same binding modes for each.
2822 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2823 if pats.is_empty() {
2827 let mut missing_vars = FxHashMap::default();
2828 let mut inconsistent_vars = FxHashMap::default();
2829 for (i, p) in pats.iter().enumerate() {
2830 let map_i = self.binding_mode_map(&p);
2832 for (j, q) in pats.iter().enumerate() {
2837 let map_j = self.binding_mode_map(&q);
2838 for (&key, &binding_i) in &map_i {
2839 if map_j.is_empty() { // Account for missing bindings when
2840 let binding_error = missing_vars // map_j has none.
2842 .or_insert(BindingError {
2844 origin: BTreeSet::new(),
2845 target: BTreeSet::new(),
2847 binding_error.origin.insert(binding_i.span);
2848 binding_error.target.insert(q.span);
2850 for (&key_j, &binding_j) in &map_j {
2851 match map_i.get(&key_j) {
2852 None => { // missing binding
2853 let binding_error = missing_vars
2855 .or_insert(BindingError {
2857 origin: BTreeSet::new(),
2858 target: BTreeSet::new(),
2860 binding_error.origin.insert(binding_j.span);
2861 binding_error.target.insert(p.span);
2863 Some(binding_i) => { // check consistent binding
2864 if binding_i.binding_mode != binding_j.binding_mode {
2867 .or_insert((binding_j.span, binding_i.span));
2875 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2876 missing_vars.sort();
2877 for (_, v) in missing_vars {
2879 *v.origin.iter().next().unwrap(),
2880 ResolutionError::VariableNotBoundInPattern(v));
2882 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2883 inconsistent_vars.sort();
2884 for (name, v) in inconsistent_vars {
2885 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2889 fn resolve_arm(&mut self, arm: &Arm) {
2890 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2892 let mut bindings_list = FxHashMap::default();
2893 for pattern in &arm.pats {
2894 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2897 // This has to happen *after* we determine which pat_idents are variants.
2898 self.check_consistent_bindings(&arm.pats);
2900 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2901 self.visit_expr(expr)
2903 self.visit_expr(&arm.body);
2905 self.ribs[ValueNS].pop();
2908 fn resolve_block(&mut self, block: &Block) {
2909 debug!("(resolving block) entering block");
2910 // Move down in the graph, if there's an anonymous module rooted here.
2911 let orig_module = self.current_module;
2912 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2914 let mut num_macro_definition_ribs = 0;
2915 if let Some(anonymous_module) = anonymous_module {
2916 debug!("(resolving block) found anonymous module, moving down");
2917 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2918 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2919 self.current_module = anonymous_module;
2920 self.finalize_current_module_macro_resolutions();
2922 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2925 // Descend into the block.
2926 for stmt in &block.stmts {
2927 if let ast::StmtKind::Item(ref item) = stmt.node {
2928 if let ast::ItemKind::MacroDef(..) = item.node {
2929 num_macro_definition_ribs += 1;
2930 let def = self.definitions.local_def_id(item.id);
2931 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2932 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2936 self.visit_stmt(stmt);
2940 self.current_module = orig_module;
2941 for _ in 0 .. num_macro_definition_ribs {
2942 self.ribs[ValueNS].pop();
2943 self.label_ribs.pop();
2945 self.ribs[ValueNS].pop();
2946 if anonymous_module.is_some() {
2947 self.ribs[TypeNS].pop();
2949 debug!("(resolving block) leaving block");
2952 fn fresh_binding(&mut self,
2955 outer_pat_id: NodeId,
2956 pat_src: PatternSource,
2957 bindings: &mut FxHashMap<Ident, NodeId>)
2959 // Add the binding to the local ribs, if it
2960 // doesn't already exist in the bindings map. (We
2961 // must not add it if it's in the bindings map
2962 // because that breaks the assumptions later
2963 // passes make about or-patterns.)
2964 let ident = ident.modern_and_legacy();
2965 let mut def = Def::Local(pat_id);
2966 match bindings.get(&ident).cloned() {
2967 Some(id) if id == outer_pat_id => {
2968 // `Variant(a, a)`, error
2972 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2976 Some(..) if pat_src == PatternSource::FnParam => {
2977 // `fn f(a: u8, a: u8)`, error
2981 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2985 Some(..) if pat_src == PatternSource::Match ||
2986 pat_src == PatternSource::IfLet ||
2987 pat_src == PatternSource::WhileLet => {
2988 // `Variant1(a) | Variant2(a)`, ok
2989 // Reuse definition from the first `a`.
2990 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2993 span_bug!(ident.span, "two bindings with the same name from \
2994 unexpected pattern source {:?}", pat_src);
2997 // A completely fresh binding, add to the lists if it's valid.
2998 if ident.name != keywords::Invalid.name() {
2999 bindings.insert(ident, outer_pat_id);
3000 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3005 PathResolution::new(def)
3008 fn resolve_pattern(&mut self,
3010 pat_src: PatternSource,
3011 // Maps idents to the node ID for the
3012 // outermost pattern that binds them.
3013 bindings: &mut FxHashMap<Ident, NodeId>) {
3014 // Visit all direct subpatterns of this pattern.
3015 let outer_pat_id = pat.id;
3016 pat.walk(&mut |pat| {
3017 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3019 PatKind::Ident(bmode, ident, ref opt_pat) => {
3020 // First try to resolve the identifier as some existing
3021 // entity, then fall back to a fresh binding.
3022 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3024 .and_then(LexicalScopeBinding::item);
3025 let resolution = binding.map(NameBinding::def).and_then(|def| {
3026 let is_syntactic_ambiguity = opt_pat.is_none() &&
3027 bmode == BindingMode::ByValue(Mutability::Immutable);
3029 Def::StructCtor(_, CtorKind::Const) |
3030 Def::VariantCtor(_, CtorKind::Const) |
3031 Def::Const(..) if is_syntactic_ambiguity => {
3032 // Disambiguate in favor of a unit struct/variant
3033 // or constant pattern.
3034 self.record_use(ident, ValueNS, binding.unwrap(), false);
3035 Some(PathResolution::new(def))
3037 Def::StructCtor(..) | Def::VariantCtor(..) |
3038 Def::Const(..) | Def::Static(..) => {
3039 // This is unambiguously a fresh binding, either syntactically
3040 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3041 // to something unusable as a pattern (e.g., constructor function),
3042 // but we still conservatively report an error, see
3043 // issues/33118#issuecomment-233962221 for one reason why.
3047 ResolutionError::BindingShadowsSomethingUnacceptable(
3048 pat_src.descr(), ident.name, binding.unwrap())
3052 Def::Fn(..) | Def::Err => {
3053 // These entities are explicitly allowed
3054 // to be shadowed by fresh bindings.
3058 span_bug!(ident.span, "unexpected definition for an \
3059 identifier in pattern: {:?}", def);
3062 }).unwrap_or_else(|| {
3063 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3066 self.record_def(pat.id, resolution);
3069 PatKind::TupleStruct(ref path, ..) => {
3070 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3073 PatKind::Path(ref qself, ref path) => {
3074 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3077 PatKind::Struct(ref path, ..) => {
3078 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3086 visit::walk_pat(self, pat);
3089 // High-level and context dependent path resolution routine.
3090 // Resolves the path and records the resolution into definition map.
3091 // If resolution fails tries several techniques to find likely
3092 // resolution candidates, suggest imports or other help, and report
3093 // errors in user friendly way.
3094 fn smart_resolve_path(&mut self,
3096 qself: Option<&QSelf>,
3098 source: PathSource<'_>)
3100 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3103 /// A variant of `smart_resolve_path` where you also specify extra
3104 /// information about where the path came from; this extra info is
3105 /// sometimes needed for the lint that recommends rewriting
3106 /// absolute paths to `crate`, so that it knows how to frame the
3107 /// suggestion. If you are just resolving a path like `foo::bar`
3108 /// that appears...somewhere, though, then you just want
3109 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3110 /// already provides.
3111 fn smart_resolve_path_with_crate_lint(
3114 qself: Option<&QSelf>,
3116 source: PathSource<'_>,
3117 crate_lint: CrateLint
3118 ) -> PathResolution {
3119 self.smart_resolve_path_fragment(
3122 &Segment::from_path(path),
3129 fn smart_resolve_path_fragment(&mut self,
3131 qself: Option<&QSelf>,
3134 source: PathSource<'_>,
3135 crate_lint: CrateLint)
3137 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3138 let ns = source.namespace();
3139 let is_expected = &|def| source.is_expected(def);
3140 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3142 // Base error is amended with one short label and possibly some longer helps/notes.
3143 let report_errors = |this: &mut Self, def: Option<Def>| {
3144 // Make the base error.
3145 let expected = source.descr_expected();
3146 let path_str = Segment::names_to_string(path);
3147 let item_str = path.last().unwrap().ident;
3148 let code = source.error_code(def.is_some());
3149 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3150 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3151 format!("not a {}", expected),
3154 let item_span = path.last().unwrap().ident.span;
3155 let (mod_prefix, mod_str) = if path.len() == 1 {
3156 (String::new(), "this scope".to_string())
3157 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3158 (String::new(), "the crate root".to_string())
3160 let mod_path = &path[..path.len() - 1];
3161 let mod_prefix = match this.resolve_path_without_parent_scope(
3162 mod_path, Some(TypeNS), false, span, CrateLint::No
3164 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3167 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3168 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3170 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3171 format!("not found in {}", mod_str),
3175 let code = DiagnosticId::Error(code.into());
3176 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3178 // Emit help message for fake-self from other languages like `this`(javascript)
3179 if ["this", "my"].contains(&&*item_str.as_str())
3180 && this.self_value_is_available(path[0].ident.span, span) {
3181 err.span_suggestion(
3185 Applicability::MaybeIncorrect,
3189 // Emit special messages for unresolved `Self` and `self`.
3190 if is_self_type(path, ns) {
3191 __diagnostic_used!(E0411);
3192 err.code(DiagnosticId::Error("E0411".into()));
3193 err.span_label(span, format!("`Self` is only available in impls, traits, \
3194 and type definitions"));
3195 return (err, Vec::new());
3197 if is_self_value(path, ns) {
3198 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3200 __diagnostic_used!(E0424);
3201 err.code(DiagnosticId::Error("E0424".into()));
3202 err.span_label(span, match source {
3203 PathSource::Pat => {
3204 format!("`self` value is a keyword \
3205 and may not be bound to \
3206 variables or shadowed")
3209 format!("`self` value is a keyword \
3210 only available in methods \
3211 with `self` parameter")
3214 return (err, Vec::new());
3217 // Try to lookup the name in more relaxed fashion for better error reporting.
3218 let ident = path.last().unwrap().ident;
3219 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3220 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3221 let enum_candidates =
3222 this.lookup_import_candidates(ident, ns, is_enum_variant);
3223 let mut enum_candidates = enum_candidates.iter()
3225 import_candidate_to_enum_paths(&suggestion)
3226 }).collect::<Vec<_>>();
3227 enum_candidates.sort();
3229 if !enum_candidates.is_empty() {
3230 // contextualize for E0412 "cannot find type", but don't belabor the point
3231 // (that it's a variant) for E0573 "expected type, found variant"
3232 let preamble = if def.is_none() {
3233 let others = match enum_candidates.len() {
3235 2 => " and 1 other".to_owned(),
3236 n => format!(" and {} others", n)
3238 format!("there is an enum variant `{}`{}; ",
3239 enum_candidates[0].0, others)
3243 let msg = format!("{}try using the variant's enum", preamble);
3245 err.span_suggestions(
3248 enum_candidates.into_iter()
3249 .map(|(_variant_path, enum_ty_path)| enum_ty_path)
3250 // variants reëxported in prelude doesn't mean `prelude::v1` is the
3251 // type name! FIXME: is there a more principled way to do this that
3252 // would work for other reëxports?
3253 .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
3254 // also say `Option` rather than `std::prelude::v1::Option`
3255 .map(|enum_ty_path| {
3256 // FIXME #56861: DRYer prelude filtering
3257 enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
3259 Applicability::MachineApplicable,
3263 if path.len() == 1 && this.self_type_is_available(span) {
3264 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3265 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3267 AssocSuggestion::Field => {
3268 err.span_suggestion(
3271 format!("self.{}", path_str),
3272 Applicability::MachineApplicable,
3274 if !self_is_available {
3275 err.span_label(span, format!("`self` value is a keyword \
3277 methods with `self` parameter"));
3280 AssocSuggestion::MethodWithSelf if self_is_available => {
3281 err.span_suggestion(
3284 format!("self.{}", path_str),
3285 Applicability::MachineApplicable,
3288 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3289 err.span_suggestion(
3292 format!("Self::{}", path_str),
3293 Applicability::MachineApplicable,
3297 return (err, candidates);
3301 let mut levenshtein_worked = false;
3303 // Try Levenshtein algorithm.
3304 let suggestion = this.lookup_typo_candidate(path, ns, is_expected, span);
3305 if let Some(suggestion) = suggestion {
3307 "{} {} with a similar name exists",
3308 suggestion.article, suggestion.kind
3310 err.span_suggestion(
3313 suggestion.candidate.to_string(),
3314 Applicability::MaybeIncorrect,
3317 levenshtein_worked = true;
3320 // Try context dependent help if relaxed lookup didn't work.
3321 if let Some(def) = def {
3322 match (def, source) {
3323 (Def::Macro(..), _) => {
3324 err.span_suggestion(
3326 "use `!` to invoke the macro",
3327 format!("{}!", path_str),
3328 Applicability::MaybeIncorrect,
3330 return (err, candidates);
3332 (Def::TyAlias(..), PathSource::Trait(_)) => {
3333 err.span_label(span, "type aliases cannot be used as traits");
3334 if nightly_options::is_nightly_build() {
3335 err.note("did you mean to use a trait alias?");
3337 return (err, candidates);
3339 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3340 ExprKind::Field(_, ident) => {
3341 err.span_suggestion(
3343 "use the path separator to refer to an item",
3344 format!("{}::{}", path_str, ident),
3345 Applicability::MaybeIncorrect,
3347 return (err, candidates);
3349 ExprKind::MethodCall(ref segment, ..) => {
3350 let span = parent.span.with_hi(segment.ident.span.hi());
3351 err.span_suggestion(
3353 "use the path separator to refer to an item",
3354 format!("{}::{}", path_str, segment.ident),
3355 Applicability::MaybeIncorrect,
3357 return (err, candidates);
3361 (Def::Enum(..), PathSource::TupleStruct)
3362 | (Def::Enum(..), PathSource::Expr(..)) => {
3363 if let Some(variants) = this.collect_enum_variants(def) {
3364 err.note(&format!("did you mean to use one \
3365 of the following variants?\n{}",
3367 .map(|suggestion| path_names_to_string(suggestion))
3368 .map(|suggestion| format!("- `{}`", suggestion))
3369 .collect::<Vec<_>>()
3373 err.note("did you mean to use one of the enum's variants?");
3375 return (err, candidates);
3377 (Def::Struct(def_id), _) if ns == ValueNS => {
3378 if let Some((ctor_def, ctor_vis))
3379 = this.struct_constructors.get(&def_id).cloned() {
3380 let accessible_ctor = this.is_accessible(ctor_vis);
3381 if is_expected(ctor_def) && !accessible_ctor {
3382 err.span_label(span, format!("constructor is not visible \
3383 here due to private fields"));
3386 // HACK(estebank): find a better way to figure out that this was a
3387 // parser issue where a struct literal is being used on an expression
3388 // where a brace being opened means a block is being started. Look
3389 // ahead for the next text to see if `span` is followed by a `{`.
3390 let sm = this.session.source_map();
3393 sp = sm.next_point(sp);
3394 match sm.span_to_snippet(sp) {
3395 Ok(ref snippet) => {
3396 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3403 let followed_by_brace = match sm.span_to_snippet(sp) {
3404 Ok(ref snippet) if snippet == "{" => true,
3407 // In case this could be a struct literal that needs to be surrounded
3408 // by parenthesis, find the appropriate span.
3410 let mut closing_brace = None;
3412 sp = sm.next_point(sp);
3413 match sm.span_to_snippet(sp) {
3414 Ok(ref snippet) => {
3416 let sp = span.to(sp);
3417 if let Ok(snippet) = sm.span_to_snippet(sp) {
3418 closing_brace = Some((sp, snippet));
3426 if i > 100 { // The bigger the span the more likely we're
3427 break; // incorrect. Bound it to 100 chars long.
3431 PathSource::Expr(Some(parent)) => {
3433 ExprKind::MethodCall(ref path_assignment, _) => {
3434 err.span_suggestion(
3435 sm.start_point(parent.span)
3436 .to(path_assignment.ident.span),
3437 "use `::` to access an associated function",
3440 path_assignment.ident),
3441 Applicability::MaybeIncorrect
3443 return (err, candidates);
3448 format!("did you mean `{} {{ /* fields */ }}`?",
3451 return (err, candidates);
3455 PathSource::Expr(None) if followed_by_brace == true => {
3456 if let Some((sp, snippet)) = closing_brace {
3457 err.span_suggestion(
3459 "surround the struct literal with parenthesis",
3460 format!("({})", snippet),
3461 Applicability::MaybeIncorrect,
3466 format!("did you mean `({} {{ /* fields */ }})`?",
3470 return (err, candidates);
3475 format!("did you mean `{} {{ /* fields */ }}`?",
3478 return (err, candidates);
3482 return (err, candidates);
3484 (Def::Union(..), _) |
3485 (Def::Variant(..), _) |
3486 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3487 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3489 return (err, candidates);
3491 (Def::SelfTy(..), _) if ns == ValueNS => {
3492 err.span_label(span, fallback_label);
3493 err.note("can't use `Self` as a constructor, you must use the \
3494 implemented struct");
3495 return (err, candidates);
3497 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3498 err.note("can't use a type alias as a constructor");
3499 return (err, candidates);
3506 if !levenshtein_worked {
3507 err.span_label(base_span, fallback_label);
3508 this.type_ascription_suggestion(&mut err, base_span);
3512 let report_errors = |this: &mut Self, def: Option<Def>| {
3513 let (err, candidates) = report_errors(this, def);
3514 let def_id = this.current_module.normal_ancestor_id;
3515 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3516 let better = def.is_some();
3517 this.use_injections.push(UseError { err, candidates, node_id, better });
3518 err_path_resolution()
3521 let resolution = match self.resolve_qpath_anywhere(
3527 source.defer_to_typeck(),
3528 source.global_by_default(),
3531 Some(resolution) if resolution.unresolved_segments() == 0 => {
3532 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3535 // Add a temporary hack to smooth the transition to new struct ctor
3536 // visibility rules. See #38932 for more details.
3538 if let Def::Struct(def_id) = resolution.base_def() {
3539 if let Some((ctor_def, ctor_vis))
3540 = self.struct_constructors.get(&def_id).cloned() {
3541 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3542 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3543 self.session.buffer_lint(lint, id, span,
3544 "private struct constructors are not usable through \
3545 re-exports in outer modules",
3547 res = Some(PathResolution::new(ctor_def));
3552 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3555 Some(resolution) if source.defer_to_typeck() => {
3556 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3557 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3558 // it needs to be added to the trait map.
3560 let item_name = path.last().unwrap().ident;
3561 let traits = self.get_traits_containing_item(item_name, ns);
3562 self.trait_map.insert(id, traits);
3566 _ => report_errors(self, None)
3569 if let PathSource::TraitItem(..) = source {} else {
3570 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3571 self.record_def(id, resolution);
3576 fn type_ascription_suggestion(&self,
3577 err: &mut DiagnosticBuilder<'_>,
3579 debug!("type_ascription_suggetion {:?}", base_span);
3580 let cm = self.session.source_map();
3581 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3582 if let Some(sp) = self.current_type_ascription.last() {
3584 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3585 sp = cm.next_point(sp);
3586 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3587 debug!("snippet {:?}", snippet);
3588 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3589 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3590 debug!("{:?} {:?}", line_sp, line_base_sp);
3592 err.span_label(base_span,
3593 "expecting a type here because of type ascription");
3594 if line_sp != line_base_sp {
3595 err.span_suggestion_short(
3597 "did you mean to use `;` here instead?",
3599 Applicability::MaybeIncorrect,
3603 } else if !snippet.trim().is_empty() {
3604 debug!("tried to find type ascription `:` token, couldn't find it");
3614 fn self_type_is_available(&mut self, span: Span) -> bool {
3615 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3616 TypeNS, None, span);
3617 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3620 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3621 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3622 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3623 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3626 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3627 fn resolve_qpath_anywhere(&mut self,
3629 qself: Option<&QSelf>,
3631 primary_ns: Namespace,
3633 defer_to_typeck: bool,
3634 global_by_default: bool,
3635 crate_lint: CrateLint)
3636 -> Option<PathResolution> {
3637 let mut fin_res = None;
3638 // FIXME: can't resolve paths in macro namespace yet, macros are
3639 // processed by the little special hack below.
3640 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3641 if i == 0 || ns != primary_ns {
3642 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3643 // If defer_to_typeck, then resolution > no resolution,
3644 // otherwise full resolution > partial resolution > no resolution.
3645 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3647 res => if fin_res.is_none() { fin_res = res },
3651 if primary_ns != MacroNS &&
3652 (self.macro_names.contains(&path[0].ident.modern()) ||
3653 self.builtin_macros.get(&path[0].ident.name).cloned()
3654 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3655 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3656 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3657 // Return some dummy definition, it's enough for error reporting.
3659 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3665 /// Handles paths that may refer to associated items.
3666 fn resolve_qpath(&mut self,
3668 qself: Option<&QSelf>,
3672 global_by_default: bool,
3673 crate_lint: CrateLint)
3674 -> Option<PathResolution> {
3676 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3677 ns={:?}, span={:?}, global_by_default={:?})",
3686 if let Some(qself) = qself {
3687 if qself.position == 0 {
3688 // This is a case like `<T>::B`, where there is no
3689 // trait to resolve. In that case, we leave the `B`
3690 // segment to be resolved by type-check.
3691 return Some(PathResolution::with_unresolved_segments(
3692 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3696 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3698 // Currently, `path` names the full item (`A::B::C`, in
3699 // our example). so we extract the prefix of that that is
3700 // the trait (the slice upto and including
3701 // `qself.position`). And then we recursively resolve that,
3702 // but with `qself` set to `None`.
3704 // However, setting `qself` to none (but not changing the
3705 // span) loses the information about where this path
3706 // *actually* appears, so for the purposes of the crate
3707 // lint we pass along information that this is the trait
3708 // name from a fully qualified path, and this also
3709 // contains the full span (the `CrateLint::QPathTrait`).
3710 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3711 let res = self.smart_resolve_path_fragment(
3714 &path[..=qself.position],
3716 PathSource::TraitItem(ns),
3717 CrateLint::QPathTrait {
3719 qpath_span: qself.path_span,
3723 // The remaining segments (the `C` in our example) will
3724 // have to be resolved by type-check, since that requires doing
3725 // trait resolution.
3726 return Some(PathResolution::with_unresolved_segments(
3727 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3731 let result = match self.resolve_path_without_parent_scope(
3738 PathResult::NonModule(path_res) => path_res,
3739 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3740 PathResolution::new(module.def().unwrap())
3742 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3743 // don't report an error right away, but try to fallback to a primitive type.
3744 // So, we are still able to successfully resolve something like
3746 // use std::u8; // bring module u8 in scope
3747 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3748 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3749 // // not to non-existent std::u8::max_value
3752 // Such behavior is required for backward compatibility.
3753 // The same fallback is used when `a` resolves to nothing.
3754 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3755 PathResult::Failed(..)
3756 if (ns == TypeNS || path.len() > 1) &&
3757 self.primitive_type_table.primitive_types
3758 .contains_key(&path[0].ident.name) => {
3759 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3760 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3762 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3763 PathResolution::new(module.def().unwrap()),
3764 PathResult::Failed(span, msg, false) => {
3765 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3766 err_path_resolution()
3768 PathResult::Module(..) | PathResult::Failed(..) => return None,
3769 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3772 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3773 path[0].ident.name != keywords::PathRoot.name() &&
3774 path[0].ident.name != keywords::DollarCrate.name() {
3775 let unqualified_result = {
3776 match self.resolve_path_without_parent_scope(
3777 &[*path.last().unwrap()],
3783 PathResult::NonModule(path_res) => path_res.base_def(),
3784 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3785 module.def().unwrap(),
3786 _ => return Some(result),
3789 if result.base_def() == unqualified_result {
3790 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3791 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3798 fn resolve_path_without_parent_scope(
3801 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3804 crate_lint: CrateLint,
3805 ) -> PathResult<'a> {
3806 // Macro and import paths must have full parent scope available during resolution,
3807 // other paths will do okay with parent module alone.
3808 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3809 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3810 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3816 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3817 parent_scope: &ParentScope<'a>,
3820 crate_lint: CrateLint,
3821 ) -> PathResult<'a> {
3822 let mut module = None;
3823 let mut allow_super = true;
3824 let mut second_binding = None;
3825 self.current_module = parent_scope.module;
3828 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3829 path_span={:?}, crate_lint={:?})",
3837 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3838 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3839 let record_segment_def = |this: &mut Self, def| {
3841 if let Some(id) = id {
3842 if !this.def_map.contains_key(&id) {
3843 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3844 this.record_def(id, PathResolution::new(def));
3850 let is_last = i == path.len() - 1;
3851 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3852 let name = ident.name;
3854 allow_super &= ns == TypeNS &&
3855 (name == keywords::SelfLower.name() ||
3856 name == keywords::Super.name());
3859 if allow_super && name == keywords::Super.name() {
3860 let mut ctxt = ident.span.ctxt().modern();
3861 let self_module = match i {
3862 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3864 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3868 if let Some(self_module) = self_module {
3869 if let Some(parent) = self_module.parent {
3870 module = Some(ModuleOrUniformRoot::Module(
3871 self.resolve_self(&mut ctxt, parent)));
3875 let msg = "there are too many initial `super`s.".to_string();
3876 return PathResult::Failed(ident.span, msg, false);
3879 if name == keywords::SelfLower.name() {
3880 let mut ctxt = ident.span.ctxt().modern();
3881 module = Some(ModuleOrUniformRoot::Module(
3882 self.resolve_self(&mut ctxt, self.current_module)));
3885 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3886 module = Some(ModuleOrUniformRoot::ExternPrelude);
3889 if name == keywords::PathRoot.name() &&
3890 ident.span.rust_2015() && self.session.rust_2018() {
3891 // `::a::b` from 2015 macro on 2018 global edition
3892 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3895 if name == keywords::PathRoot.name() ||
3896 name == keywords::Crate.name() ||
3897 name == keywords::DollarCrate.name() {
3898 // `::a::b`, `crate::a::b` or `$crate::a::b`
3899 module = Some(ModuleOrUniformRoot::Module(
3900 self.resolve_crate_root(ident)));
3906 // Report special messages for path segment keywords in wrong positions.
3907 if ident.is_path_segment_keyword() && i != 0 {
3908 let name_str = if name == keywords::PathRoot.name() {
3909 "crate root".to_string()
3911 format!("`{}`", name)
3913 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3914 format!("global paths cannot start with {}", name_str)
3916 format!("{} in paths can only be used in start position", name_str)
3918 return PathResult::Failed(ident.span, msg, false);
3921 let binding = if let Some(module) = module {
3922 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3923 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3924 assert!(ns == TypeNS);
3925 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3926 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3927 record_used, path_span)
3929 let record_used_id =
3930 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3931 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3932 // we found a locally-imported or available item/module
3933 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3934 // we found a local variable or type param
3935 Some(LexicalScopeBinding::Def(def))
3936 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3937 record_segment_def(self, def);
3938 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3942 _ => Err(Determinacy::determined(record_used)),
3949 second_binding = Some(binding);
3951 let def = binding.def();
3952 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3953 if let Some(next_module) = binding.module() {
3954 module = Some(ModuleOrUniformRoot::Module(next_module));
3955 record_segment_def(self, def);
3956 } else if def == Def::ToolMod && i + 1 != path.len() {
3957 if binding.is_import() {
3958 self.session.struct_span_err(
3959 ident.span, "cannot use a tool module through an import"
3961 binding.span, "the tool module imported here"
3964 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3965 return PathResult::NonModule(PathResolution::new(def));
3966 } else if def == Def::Err {
3967 return PathResult::NonModule(err_path_resolution());
3968 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3969 self.lint_if_path_starts_with_module(
3975 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3976 def, path.len() - i - 1
3979 return PathResult::Failed(ident.span,
3980 format!("not a module `{}`", ident),
3984 Err(Undetermined) => return PathResult::Indeterminate,
3985 Err(Determined) => {
3986 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3987 if opt_ns.is_some() && !module.is_normal() {
3988 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3989 module.def().unwrap(), path.len() - i
3993 let module_def = match module {
3994 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3997 let msg = if module_def == self.graph_root.def() {
3998 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3999 let mut candidates =
4000 self.lookup_import_candidates(ident, TypeNS, is_mod);
4001 candidates.sort_by_cached_key(|c| {
4002 (c.path.segments.len(), c.path.to_string())
4004 if let Some(candidate) = candidates.get(0) {
4005 format!("did you mean `{}`?", candidate.path)
4006 } else if !ident.is_reserved() {
4007 format!("maybe a missing `extern crate {};`?", ident)
4009 // the parser will already have complained about the keyword being used
4010 return PathResult::NonModule(err_path_resolution());
4013 format!("use of undeclared type or module `{}`", ident)
4015 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
4017 return PathResult::Failed(ident.span, msg, is_last);
4022 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
4024 PathResult::Module(match module {
4025 Some(module) => module,
4026 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
4027 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
4031 fn lint_if_path_starts_with_module(
4033 crate_lint: CrateLint,
4036 second_binding: Option<&NameBinding<'_>>,
4038 let (diag_id, diag_span) = match crate_lint {
4039 CrateLint::No => return,
4040 CrateLint::SimplePath(id) => (id, path_span),
4041 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
4042 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
4045 let first_name = match path.get(0) {
4046 // In the 2018 edition this lint is a hard error, so nothing to do
4047 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
4051 // We're only interested in `use` paths which should start with
4052 // `{{root}}` currently.
4053 if first_name != keywords::PathRoot.name() {
4058 // If this import looks like `crate::...` it's already good
4059 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
4060 // Otherwise go below to see if it's an extern crate
4062 // If the path has length one (and it's `PathRoot` most likely)
4063 // then we don't know whether we're gonna be importing a crate or an
4064 // item in our crate. Defer this lint to elsewhere
4068 // If the first element of our path was actually resolved to an
4069 // `ExternCrate` (also used for `crate::...`) then no need to issue a
4070 // warning, this looks all good!
4071 if let Some(binding) = second_binding {
4072 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
4073 // Careful: we still want to rewrite paths from
4074 // renamed extern crates.
4075 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
4081 let diag = lint::builtin::BuiltinLintDiagnostics
4082 ::AbsPathWithModule(diag_span);
4083 self.session.buffer_lint_with_diagnostic(
4084 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
4086 "absolute paths must start with `self`, `super`, \
4087 `crate`, or an external crate name in the 2018 edition",
4091 // Resolve a local definition, potentially adjusting for closures.
4092 fn adjust_local_def(&mut self,
4097 span: Span) -> Def {
4098 let ribs = &self.ribs[ns][rib_index + 1..];
4100 // An invalid forward use of a type parameter from a previous default.
4101 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4103 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4105 assert_eq!(def, Def::Err);
4111 span_bug!(span, "unexpected {:?} in bindings", def)
4113 Def::Local(node_id) => {
4116 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4117 ForwardTyParamBanRibKind => {
4118 // Nothing to do. Continue.
4120 ClosureRibKind(function_id) => {
4123 let seen = self.freevars_seen
4126 if let Some(&index) = seen.get(&node_id) {
4127 def = Def::Upvar(node_id, index, function_id);
4130 let vec = self.freevars
4133 let depth = vec.len();
4134 def = Def::Upvar(node_id, depth, function_id);
4141 seen.insert(node_id, depth);
4144 ItemRibKind | TraitOrImplItemRibKind => {
4145 // This was an attempt to access an upvar inside a
4146 // named function item. This is not allowed, so we
4149 resolve_error(self, span,
4150 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4154 ConstantItemRibKind => {
4155 // Still doesn't deal with upvars
4157 resolve_error(self, span,
4158 ResolutionError::AttemptToUseNonConstantValueInConstant);
4165 Def::TyParam(..) | Def::SelfTy(..) => {
4168 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4169 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4170 ConstantItemRibKind => {
4171 // Nothing to do. Continue.
4174 // This was an attempt to use a type parameter outside
4177 resolve_error(self, span,
4178 ResolutionError::TypeParametersFromOuterFunction(def));
4190 fn lookup_assoc_candidate<FilterFn>(&mut self,
4193 filter_fn: FilterFn)
4194 -> Option<AssocSuggestion>
4195 where FilterFn: Fn(Def) -> bool
4197 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4199 TyKind::Path(None, _) => Some(t.id),
4200 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4201 // This doesn't handle the remaining `Ty` variants as they are not
4202 // that commonly the self_type, it might be interesting to provide
4203 // support for those in future.
4208 // Fields are generally expected in the same contexts as locals.
4209 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4210 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4211 // Look for a field with the same name in the current self_type.
4212 if let Some(resolution) = self.def_map.get(&node_id) {
4213 match resolution.base_def() {
4214 Def::Struct(did) | Def::Union(did)
4215 if resolution.unresolved_segments() == 0 => {
4216 if let Some(field_names) = self.field_names.get(&did) {
4217 if field_names.iter().any(|&field_name| ident.name == field_name) {
4218 return Some(AssocSuggestion::Field);
4228 // Look for associated items in the current trait.
4229 if let Some((module, _)) = self.current_trait_ref {
4230 if let Ok(binding) = self.resolve_ident_in_module(
4231 ModuleOrUniformRoot::Module(module),
4238 let def = binding.def();
4240 return Some(if self.has_self.contains(&def.def_id()) {
4241 AssocSuggestion::MethodWithSelf
4243 AssocSuggestion::AssocItem
4252 fn lookup_typo_candidate<FilterFn>(
4256 filter_fn: FilterFn,
4258 ) -> Option<TypoSuggestion>
4260 FilterFn: Fn(Def) -> bool,
4262 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4263 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4264 if let Some(binding) = resolution.borrow().binding {
4265 if filter_fn(binding.def()) {
4266 names.push(TypoSuggestion {
4267 candidate: ident.name,
4268 article: binding.def().article(),
4269 kind: binding.def().kind_name(),
4276 let mut names = Vec::new();
4277 if path.len() == 1 {
4278 // Search in lexical scope.
4279 // Walk backwards up the ribs in scope and collect candidates.
4280 for rib in self.ribs[ns].iter().rev() {
4281 // Locals and type parameters
4282 for (ident, def) in &rib.bindings {
4283 if filter_fn(*def) {
4284 names.push(TypoSuggestion {
4285 candidate: ident.name,
4286 article: def.article(),
4287 kind: def.kind_name(),
4292 if let ModuleRibKind(module) = rib.kind {
4293 // Items from this module
4294 add_module_candidates(module, &mut names);
4296 if let ModuleKind::Block(..) = module.kind {
4297 // We can see through blocks
4299 // Items from the prelude
4300 if !module.no_implicit_prelude {
4301 names.extend(self.extern_prelude.iter().map(|(ident, _)| {
4303 candidate: ident.name,
4308 if let Some(prelude) = self.prelude {
4309 add_module_candidates(prelude, &mut names);
4316 // Add primitive types to the mix
4317 if filter_fn(Def::PrimTy(Bool)) {
4319 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4323 kind: "primitive type",
4329 // Search in module.
4330 let mod_path = &path[..path.len() - 1];
4331 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4332 mod_path, Some(TypeNS), false, span, CrateLint::No
4334 if let ModuleOrUniformRoot::Module(module) = module {
4335 add_module_candidates(module, &mut names);
4340 let name = path[path.len() - 1].ident.name;
4341 // Make sure error reporting is deterministic.
4342 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4344 match find_best_match_for_name(
4345 names.iter().map(|suggestion| &suggestion.candidate),
4349 Some(found) if found != name => names
4351 .find(|suggestion| suggestion.candidate == found),
4356 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4357 where F: FnOnce(&mut Resolver<'_>)
4359 if let Some(label) = label {
4360 self.unused_labels.insert(id, label.ident.span);
4361 let def = Def::Label(id);
4362 self.with_label_rib(|this| {
4363 let ident = label.ident.modern_and_legacy();
4364 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4372 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4373 self.with_resolved_label(label, id, |this| this.visit_block(block));
4376 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4377 // First, record candidate traits for this expression if it could
4378 // result in the invocation of a method call.
4380 self.record_candidate_traits_for_expr_if_necessary(expr);
4382 // Next, resolve the node.
4384 ExprKind::Path(ref qself, ref path) => {
4385 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4386 visit::walk_expr(self, expr);
4389 ExprKind::Struct(ref path, ..) => {
4390 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4391 visit::walk_expr(self, expr);
4394 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4395 let def = self.search_label(label.ident, |rib, ident| {
4396 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4400 // Search again for close matches...
4401 // Picks the first label that is "close enough", which is not necessarily
4402 // the closest match
4403 let close_match = self.search_label(label.ident, |rib, ident| {
4404 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4405 find_best_match_for_name(names, &*ident.as_str(), None)
4407 self.record_def(expr.id, err_path_resolution());
4410 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4413 Some(Def::Label(id)) => {
4414 // Since this def is a label, it is never read.
4415 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4416 self.unused_labels.remove(&id);
4419 span_bug!(expr.span, "label wasn't mapped to a label def!");
4423 // visit `break` argument if any
4424 visit::walk_expr(self, expr);
4427 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4428 self.visit_expr(subexpression);
4430 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4431 let mut bindings_list = FxHashMap::default();
4433 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4435 // This has to happen *after* we determine which pat_idents are variants
4436 self.check_consistent_bindings(pats);
4437 self.visit_block(if_block);
4438 self.ribs[ValueNS].pop();
4440 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4443 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4445 ExprKind::While(ref subexpression, ref block, label) => {
4446 self.with_resolved_label(label, expr.id, |this| {
4447 this.visit_expr(subexpression);
4448 this.visit_block(block);
4452 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4453 self.with_resolved_label(label, expr.id, |this| {
4454 this.visit_expr(subexpression);
4455 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4456 let mut bindings_list = FxHashMap::default();
4458 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4460 // This has to happen *after* we determine which pat_idents are variants.
4461 this.check_consistent_bindings(pats);
4462 this.visit_block(block);
4463 this.ribs[ValueNS].pop();
4467 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4468 self.visit_expr(subexpression);
4469 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4470 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4472 self.resolve_labeled_block(label, expr.id, block);
4474 self.ribs[ValueNS].pop();
4477 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4479 // Equivalent to `visit::walk_expr` + passing some context to children.
4480 ExprKind::Field(ref subexpression, _) => {
4481 self.resolve_expr(subexpression, Some(expr));
4483 ExprKind::MethodCall(ref segment, ref arguments) => {
4484 let mut arguments = arguments.iter();
4485 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4486 for argument in arguments {
4487 self.resolve_expr(argument, None);
4489 self.visit_path_segment(expr.span, segment);
4492 ExprKind::Call(ref callee, ref arguments) => {
4493 self.resolve_expr(callee, Some(expr));
4494 for argument in arguments {
4495 self.resolve_expr(argument, None);
4498 ExprKind::Type(ref type_expr, _) => {
4499 self.current_type_ascription.push(type_expr.span);
4500 visit::walk_expr(self, expr);
4501 self.current_type_ascription.pop();
4503 // Resolve the body of async exprs inside the async closure to which they desugar
4504 ExprKind::Async(_, async_closure_id, ref block) => {
4505 let rib_kind = ClosureRibKind(async_closure_id);
4506 self.ribs[ValueNS].push(Rib::new(rib_kind));
4507 self.label_ribs.push(Rib::new(rib_kind));
4508 self.visit_block(&block);
4509 self.label_ribs.pop();
4510 self.ribs[ValueNS].pop();
4512 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4513 // resolve the arguments within the proper scopes so that usages of them inside the
4514 // closure are detected as upvars rather than normal closure arg usages.
4516 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4517 ref fn_decl, ref body, _span,
4519 let rib_kind = ClosureRibKind(expr.id);
4520 self.ribs[ValueNS].push(Rib::new(rib_kind));
4521 self.label_ribs.push(Rib::new(rib_kind));
4522 // Resolve arguments:
4523 let mut bindings_list = FxHashMap::default();
4524 for argument in &fn_decl.inputs {
4525 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4526 self.visit_ty(&argument.ty);
4528 // No need to resolve return type-- the outer closure return type is
4529 // FunctionRetTy::Default
4531 // Now resolve the inner closure
4533 let rib_kind = ClosureRibKind(inner_closure_id);
4534 self.ribs[ValueNS].push(Rib::new(rib_kind));
4535 self.label_ribs.push(Rib::new(rib_kind));
4536 // No need to resolve arguments: the inner closure has none.
4537 // Resolve the return type:
4538 visit::walk_fn_ret_ty(self, &fn_decl.output);
4540 self.visit_expr(body);
4541 self.label_ribs.pop();
4542 self.ribs[ValueNS].pop();
4544 self.label_ribs.pop();
4545 self.ribs[ValueNS].pop();
4548 visit::walk_expr(self, expr);
4553 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4555 ExprKind::Field(_, ident) => {
4556 // FIXME(#6890): Even though you can't treat a method like a
4557 // field, we need to add any trait methods we find that match
4558 // the field name so that we can do some nice error reporting
4559 // later on in typeck.
4560 let traits = self.get_traits_containing_item(ident, ValueNS);
4561 self.trait_map.insert(expr.id, traits);
4563 ExprKind::MethodCall(ref segment, ..) => {
4564 debug!("(recording candidate traits for expr) recording traits for {}",
4566 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4567 self.trait_map.insert(expr.id, traits);
4575 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4576 -> Vec<TraitCandidate> {
4577 debug!("(getting traits containing item) looking for '{}'", ident.name);
4579 let mut found_traits = Vec::new();
4580 // Look for the current trait.
4581 if let Some((module, _)) = self.current_trait_ref {
4582 if self.resolve_ident_in_module(
4583 ModuleOrUniformRoot::Module(module),
4590 let def_id = module.def_id().unwrap();
4591 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4595 ident.span = ident.span.modern();
4596 let mut search_module = self.current_module;
4598 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4599 search_module = unwrap_or!(
4600 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4604 if let Some(prelude) = self.prelude {
4605 if !search_module.no_implicit_prelude {
4606 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4613 fn get_traits_in_module_containing_item(&mut self,
4617 found_traits: &mut Vec<TraitCandidate>) {
4618 assert!(ns == TypeNS || ns == ValueNS);
4619 let mut traits = module.traits.borrow_mut();
4620 if traits.is_none() {
4621 let mut collected_traits = Vec::new();
4622 module.for_each_child(|name, ns, binding| {
4623 if ns != TypeNS { return }
4624 if let Def::Trait(_) = binding.def() {
4625 collected_traits.push((name, binding));
4628 *traits = Some(collected_traits.into_boxed_slice());
4631 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4632 let module = binding.module().unwrap();
4633 let mut ident = ident;
4634 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4637 if self.resolve_ident_in_module_unadjusted(
4638 ModuleOrUniformRoot::Module(module),
4644 let import_id = match binding.kind {
4645 NameBindingKind::Import { directive, .. } => {
4646 self.maybe_unused_trait_imports.insert(directive.id);
4647 self.add_to_glob_map(&directive, trait_name);
4652 let trait_def_id = module.def_id().unwrap();
4653 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4658 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4659 lookup_ident: Ident,
4660 namespace: Namespace,
4661 start_module: &'a ModuleData<'a>,
4663 filter_fn: FilterFn)
4664 -> Vec<ImportSuggestion>
4665 where FilterFn: Fn(Def) -> bool
4667 let mut candidates = Vec::new();
4668 let mut seen_modules = FxHashSet::default();
4669 let not_local_module = crate_name != keywords::Crate.ident();
4670 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4672 while let Some((in_module,
4674 in_module_is_extern)) = worklist.pop() {
4675 self.populate_module_if_necessary(in_module);
4677 // We have to visit module children in deterministic order to avoid
4678 // instabilities in reported imports (#43552).
4679 in_module.for_each_child_stable(|ident, ns, name_binding| {
4680 // avoid imports entirely
4681 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4682 // avoid non-importable candidates as well
4683 if !name_binding.is_importable() { return; }
4685 // collect results based on the filter function
4686 if ident.name == lookup_ident.name && ns == namespace {
4687 if filter_fn(name_binding.def()) {
4689 let mut segms = path_segments.clone();
4690 if lookup_ident.span.rust_2018() {
4691 // crate-local absolute paths start with `crate::` in edition 2018
4692 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4694 0, ast::PathSegment::from_ident(crate_name)
4698 segms.push(ast::PathSegment::from_ident(ident));
4700 span: name_binding.span,
4703 // the entity is accessible in the following cases:
4704 // 1. if it's defined in the same crate, it's always
4705 // accessible (since private entities can be made public)
4706 // 2. if it's defined in another crate, it's accessible
4707 // only if both the module is public and the entity is
4708 // declared as public (due to pruning, we don't explore
4709 // outside crate private modules => no need to check this)
4710 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4711 candidates.push(ImportSuggestion { path });
4716 // collect submodules to explore
4717 if let Some(module) = name_binding.module() {
4719 let mut path_segments = path_segments.clone();
4720 path_segments.push(ast::PathSegment::from_ident(ident));
4722 let is_extern_crate_that_also_appears_in_prelude =
4723 name_binding.is_extern_crate() &&
4724 lookup_ident.span.rust_2018();
4726 let is_visible_to_user =
4727 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4729 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4730 // add the module to the lookup
4731 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4732 if seen_modules.insert(module.def_id().unwrap()) {
4733 worklist.push((module, path_segments, is_extern));
4743 /// When name resolution fails, this method can be used to look up candidate
4744 /// entities with the expected name. It allows filtering them using the
4745 /// supplied predicate (which should be used to only accept the types of
4746 /// definitions expected e.g., traits). The lookup spans across all crates.
4748 /// NOTE: The method does not look into imports, but this is not a problem,
4749 /// since we report the definitions (thus, the de-aliased imports).
4750 fn lookup_import_candidates<FilterFn>(&mut self,
4751 lookup_ident: Ident,
4752 namespace: Namespace,
4753 filter_fn: FilterFn)
4754 -> Vec<ImportSuggestion>
4755 where FilterFn: Fn(Def) -> bool
4757 let mut suggestions = self.lookup_import_candidates_from_module(
4758 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4760 if lookup_ident.span.rust_2018() {
4761 let extern_prelude_names = self.extern_prelude.clone();
4762 for (ident, _) in extern_prelude_names.into_iter() {
4763 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4765 let crate_root = self.get_module(DefId {
4767 index: CRATE_DEF_INDEX,
4769 self.populate_module_if_necessary(&crate_root);
4771 suggestions.extend(self.lookup_import_candidates_from_module(
4772 lookup_ident, namespace, crate_root, ident, &filter_fn));
4780 fn find_module(&mut self,
4782 -> Option<(Module<'a>, ImportSuggestion)>
4784 let mut result = None;
4785 let mut seen_modules = FxHashSet::default();
4786 let mut worklist = vec![(self.graph_root, Vec::new())];
4788 while let Some((in_module, path_segments)) = worklist.pop() {
4789 // abort if the module is already found
4790 if result.is_some() { break; }
4792 self.populate_module_if_necessary(in_module);
4794 in_module.for_each_child_stable(|ident, _, name_binding| {
4795 // abort if the module is already found or if name_binding is private external
4796 if result.is_some() || !name_binding.vis.is_visible_locally() {
4799 if let Some(module) = name_binding.module() {
4801 let mut path_segments = path_segments.clone();
4802 path_segments.push(ast::PathSegment::from_ident(ident));
4803 if module.def() == Some(module_def) {
4805 span: name_binding.span,
4806 segments: path_segments,
4808 result = Some((module, ImportSuggestion { path }));
4810 // add the module to the lookup
4811 if seen_modules.insert(module.def_id().unwrap()) {
4812 worklist.push((module, path_segments));
4822 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4823 if let Def::Enum(..) = enum_def {} else {
4824 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4827 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4828 self.populate_module_if_necessary(enum_module);
4830 let mut variants = Vec::new();
4831 enum_module.for_each_child_stable(|ident, _, name_binding| {
4832 if let Def::Variant(..) = name_binding.def() {
4833 let mut segms = enum_import_suggestion.path.segments.clone();
4834 segms.push(ast::PathSegment::from_ident(ident));
4835 variants.push(Path {
4836 span: name_binding.span,
4845 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4846 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4847 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4848 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4852 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4854 ast::VisibilityKind::Public => ty::Visibility::Public,
4855 ast::VisibilityKind::Crate(..) => {
4856 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4858 ast::VisibilityKind::Inherited => {
4859 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4861 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4862 // For visibilities we are not ready to provide correct implementation of "uniform
4863 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4864 // On 2015 edition visibilities are resolved as crate-relative by default,
4865 // so we are prepending a root segment if necessary.
4866 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4867 let crate_root = if ident.is_path_segment_keyword() {
4869 } else if ident.span.rust_2018() {
4870 let msg = "relative paths are not supported in visibilities on 2018 edition";
4871 self.session.struct_span_err(ident.span, msg)
4875 format!("crate::{}", path),
4876 Applicability::MaybeIncorrect,
4879 return ty::Visibility::Public;
4881 let ctxt = ident.span.ctxt();
4882 Some(Segment::from_ident(Ident::new(
4883 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4887 let segments = crate_root.into_iter()
4888 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4889 let def = self.smart_resolve_path_fragment(
4894 PathSource::Visibility,
4895 CrateLint::SimplePath(id),
4897 if def == Def::Err {
4898 ty::Visibility::Public
4900 let vis = ty::Visibility::Restricted(def.def_id());
4901 if self.is_accessible(vis) {
4904 self.session.span_err(path.span, "visibilities can only be restricted \
4905 to ancestor modules");
4906 ty::Visibility::Public
4913 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4914 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4917 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4918 vis.is_accessible_from(module.normal_ancestor_id, self)
4921 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4922 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4923 if !ptr::eq(module, old_module) {
4924 span_bug!(binding.span, "parent module is reset for binding");
4929 fn disambiguate_legacy_vs_modern(
4931 legacy: &'a NameBinding<'a>,
4932 modern: &'a NameBinding<'a>,
4934 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4935 // is disambiguated to mitigate regressions from macro modularization.
4936 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4937 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4938 self.binding_parent_modules.get(&PtrKey(modern))) {
4939 (Some(legacy), Some(modern)) =>
4940 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4941 modern.is_ancestor_of(legacy),
4946 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4947 if b.span.is_dummy() {
4948 let add_built_in = match b.def() {
4949 // These already contain the "built-in" prefix or look bad with it.
4950 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4953 let (built_in, from) = if from_prelude {
4954 ("", " from prelude")
4955 } else if b.is_extern_crate() && !b.is_import() &&
4956 self.session.opts.externs.get(&ident.as_str()).is_some() {
4957 ("", " passed with `--extern`")
4958 } else if add_built_in {
4964 let article = if built_in.is_empty() { b.article() } else { "a" };
4965 format!("{a}{built_in} {thing}{from}",
4966 a = article, thing = b.descr(), built_in = built_in, from = from)
4968 let introduced = if b.is_import() { "imported" } else { "defined" };
4969 format!("the {thing} {introduced} here",
4970 thing = b.descr(), introduced = introduced)
4974 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4975 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4976 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4977 // We have to print the span-less alternative first, otherwise formatting looks bad.
4978 (b2, b1, misc2, misc1, true)
4980 (b1, b2, misc1, misc2, false)
4983 let mut err = struct_span_err!(self.session, ident.span, E0659,
4984 "`{ident}` is ambiguous ({why})",
4985 ident = ident, why = kind.descr());
4986 err.span_label(ident.span, "ambiguous name");
4988 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4989 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4990 let note_msg = format!("`{ident}` could{also} refer to {what}",
4991 ident = ident, also = also, what = what);
4993 let mut help_msgs = Vec::new();
4994 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4995 kind == AmbiguityKind::GlobVsExpanded ||
4996 kind == AmbiguityKind::GlobVsOuter &&
4997 swapped != also.is_empty()) {
4998 help_msgs.push(format!("consider adding an explicit import of \
4999 `{ident}` to disambiguate", ident = ident))
5001 if b.is_extern_crate() && ident.span.rust_2018() {
5002 help_msgs.push(format!(
5003 "use `::{ident}` to refer to this {thing} unambiguously",
5004 ident = ident, thing = b.descr(),
5007 if misc == AmbiguityErrorMisc::SuggestCrate {
5008 help_msgs.push(format!(
5009 "use `crate::{ident}` to refer to this {thing} unambiguously",
5010 ident = ident, thing = b.descr(),
5012 } else if misc == AmbiguityErrorMisc::SuggestSelf {
5013 help_msgs.push(format!(
5014 "use `self::{ident}` to refer to this {thing} unambiguously",
5015 ident = ident, thing = b.descr(),
5019 err.span_note(b.span, ¬e_msg);
5020 for (i, help_msg) in help_msgs.iter().enumerate() {
5021 let or = if i == 0 { "" } else { "or " };
5022 err.help(&format!("{}{}", or, help_msg));
5026 could_refer_to(b1, misc1, "");
5027 could_refer_to(b2, misc2, " also");
5031 fn report_errors(&mut self, krate: &Crate) {
5032 self.report_with_use_injections(krate);
5034 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
5035 let msg = "macro-expanded `macro_export` macros from the current crate \
5036 cannot be referred to by absolute paths";
5037 self.session.buffer_lint_with_diagnostic(
5038 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
5039 CRATE_NODE_ID, span_use, msg,
5040 lint::builtin::BuiltinLintDiagnostics::
5041 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
5045 for ambiguity_error in &self.ambiguity_errors {
5046 self.report_ambiguity_error(ambiguity_error);
5049 let mut reported_spans = FxHashSet::default();
5050 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
5051 if reported_spans.insert(dedup_span) {
5052 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
5053 binding.descr(), ident.name);
5058 fn report_with_use_injections(&mut self, krate: &Crate) {
5059 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5060 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5061 if !candidates.is_empty() {
5062 show_candidates(&mut err, span, &candidates, better, found_use);
5068 fn report_conflict<'b>(&mut self,
5072 new_binding: &NameBinding<'b>,
5073 old_binding: &NameBinding<'b>) {
5074 // Error on the second of two conflicting names
5075 if old_binding.span.lo() > new_binding.span.lo() {
5076 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5079 let container = match parent.kind {
5080 ModuleKind::Def(Def::Mod(_), _) => "module",
5081 ModuleKind::Def(Def::Trait(_), _) => "trait",
5082 ModuleKind::Block(..) => "block",
5086 let old_noun = match old_binding.is_import() {
5088 false => "definition",
5091 let new_participle = match new_binding.is_import() {
5096 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5098 if let Some(s) = self.name_already_seen.get(&name) {
5104 let old_kind = match (ns, old_binding.module()) {
5105 (ValueNS, _) => "value",
5106 (MacroNS, _) => "macro",
5107 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5108 (TypeNS, Some(module)) if module.is_normal() => "module",
5109 (TypeNS, Some(module)) if module.is_trait() => "trait",
5110 (TypeNS, _) => "type",
5113 let msg = format!("the name `{}` is defined multiple times", name);
5115 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5116 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5117 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5118 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5119 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5121 _ => match (old_binding.is_import(), new_binding.is_import()) {
5122 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5123 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5124 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5128 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5133 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5135 self.session.source_map().def_span(old_binding.span),
5136 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5139 // See https://github.com/rust-lang/rust/issues/32354
5140 use NameBindingKind::Import;
5141 let directive = match (&new_binding.kind, &old_binding.kind) {
5142 // If there are two imports where one or both have attributes then prefer removing the
5143 // import without attributes.
5144 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5145 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5146 (new.has_attributes || old.has_attributes)
5148 if old.has_attributes {
5149 Some((new, new_binding.span, true))
5151 Some((old, old_binding.span, true))
5154 // Otherwise prioritize the new binding.
5155 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5156 Some((directive, new_binding.span, other.is_import())),
5157 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5158 Some((directive, old_binding.span, other.is_import())),
5162 // Check if the target of the use for both bindings is the same.
5163 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5164 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5165 let from_item = self.extern_prelude.get(&ident)
5166 .map(|entry| entry.introduced_by_item)
5168 // Only suggest removing an import if both bindings are to the same def, if both spans
5169 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5170 // been introduced by a item.
5171 let should_remove_import = duplicate && !has_dummy_span &&
5172 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5175 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5176 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5177 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5178 // Simple case - remove the entire import. Due to the above match arm, this can
5179 // only be a single use so just remove it entirely.
5180 err.span_suggestion(
5181 directive.use_span_with_attributes,
5182 "remove unnecessary import",
5184 Applicability::MaybeIncorrect,
5187 Some((directive, span, _)) =>
5188 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5193 self.name_already_seen.insert(name, span);
5196 /// This function adds a suggestion to change the binding name of a new import that conflicts
5197 /// with an existing import.
5199 /// ```ignore (diagnostic)
5200 /// help: you can use `as` to change the binding name of the import
5202 /// LL | use foo::bar as other_bar;
5203 /// | ^^^^^^^^^^^^^^^^^^^^^
5205 fn add_suggestion_for_rename_of_use(
5207 err: &mut DiagnosticBuilder<'_>,
5209 directive: &ImportDirective<'_>,
5212 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5213 format!("Other{}", name)
5215 format!("other_{}", name)
5218 let mut suggestion = None;
5219 match directive.subclass {
5220 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5221 suggestion = Some(format!("self as {}", suggested_name)),
5222 ImportDirectiveSubclass::SingleImport { source, .. } => {
5223 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5224 .map(|pos| pos as usize) {
5225 if let Ok(snippet) = self.session.source_map()
5226 .span_to_snippet(binding_span) {
5227 if pos <= snippet.len() {
5228 suggestion = Some(format!(
5232 if snippet.ends_with(";") { ";" } else { "" }
5238 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5239 suggestion = Some(format!(
5240 "extern crate {} as {};",
5241 source.unwrap_or(target.name),
5244 _ => unreachable!(),
5247 let rename_msg = "you can use `as` to change the binding name of the import";
5248 if let Some(suggestion) = suggestion {
5249 err.span_suggestion(
5253 Applicability::MaybeIncorrect,
5256 err.span_label(binding_span, rename_msg);
5260 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5261 /// nested. In the following example, this function will be invoked to remove the `a` binding
5262 /// in the second use statement:
5264 /// ```ignore (diagnostic)
5265 /// use issue_52891::a;
5266 /// use issue_52891::{d, a, e};
5269 /// The following suggestion will be added:
5271 /// ```ignore (diagnostic)
5272 /// use issue_52891::{d, a, e};
5273 /// ^-- help: remove unnecessary import
5276 /// If the nested use contains only one import then the suggestion will remove the entire
5279 /// It is expected that the directive provided is a nested import - this isn't checked by the
5280 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5281 /// as characters expected by span manipulations won't be present.
5282 fn add_suggestion_for_duplicate_nested_use(
5284 err: &mut DiagnosticBuilder<'_>,
5285 directive: &ImportDirective<'_>,
5288 assert!(directive.is_nested());
5289 let message = "remove unnecessary import";
5290 let source_map = self.session.source_map();
5292 // Two examples will be used to illustrate the span manipulations we're doing:
5294 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5295 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5296 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5297 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5299 // Find the span of everything after the binding.
5300 // ie. `a, e};` or `a};`
5301 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5303 // Find everything after the binding but not including the binding.
5304 // ie. `, e};` or `};`
5305 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5307 // Keep characters in the span until we encounter something that isn't a comma or
5311 // Also note whether a closing brace character was encountered. If there
5312 // was, then later go backwards to remove any trailing commas that are left.
5313 let mut found_closing_brace = false;
5314 let after_binding_until_next_binding = source_map.span_take_while(
5315 after_binding_until_end,
5317 if ch == '}' { found_closing_brace = true; }
5318 ch == ' ' || ch == ','
5322 // Combine the two spans.
5323 // ie. `a, ` or `a`.
5325 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5326 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5328 // If there was a closing brace then identify the span to remove any trailing commas from
5329 // previous imports.
5330 if found_closing_brace {
5331 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5332 // `prev_source` will contain all of the source that came before the span.
5333 // Then split based on a command and take the first (ie. closest to our span)
5334 // snippet. In the example, this is a space.
5335 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5336 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5337 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5338 let prev_comma = prev_comma.first().unwrap();
5339 let prev_starting_brace = prev_starting_brace.first().unwrap();
5341 // If the amount of source code before the comma is greater than
5342 // the amount of source code before the starting brace then we've only
5343 // got one item in the nested item (eg. `issue_52891::{self}`).
5344 if prev_comma.len() > prev_starting_brace.len() {
5345 // So just remove the entire line...
5346 err.span_suggestion(
5347 directive.use_span_with_attributes,
5350 Applicability::MaybeIncorrect,
5355 let span = span.with_lo(BytePos(
5356 // Take away the number of bytes for the characters we've found and an
5357 // extra for the comma.
5358 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5360 err.span_suggestion(
5361 span, message, String::new(), Applicability::MaybeIncorrect,
5368 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5371 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5372 -> Option<&'a NameBinding<'a>> {
5373 if ident.is_path_segment_keyword() {
5374 // Make sure `self`, `super` etc produce an error when passed to here.
5377 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5378 if let Some(binding) = entry.extern_crate_item {
5379 if !speculative && entry.introduced_by_item {
5380 self.record_use(ident, TypeNS, binding, false);
5384 let crate_id = if !speculative {
5385 self.crate_loader.process_path_extern(ident.name, ident.span)
5386 } else if let Some(crate_id) =
5387 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5392 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5393 self.populate_module_if_necessary(&crate_root);
5394 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5395 .to_name_binding(self.arenas))
5401 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5402 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5405 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5406 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5409 fn names_to_string(idents: &[Ident]) -> String {
5410 let mut result = String::new();
5411 for (i, ident) in idents.iter()
5412 .filter(|ident| ident.name != keywords::PathRoot.name())
5415 result.push_str("::");
5417 result.push_str(&ident.as_str());
5422 fn path_names_to_string(path: &Path) -> String {
5423 names_to_string(&path.segments.iter()
5424 .map(|seg| seg.ident)
5425 .collect::<Vec<_>>())
5428 /// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5429 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5430 let variant_path = &suggestion.path;
5431 let variant_path_string = path_names_to_string(variant_path);
5433 let path_len = suggestion.path.segments.len();
5434 let enum_path = ast::Path {
5435 span: suggestion.path.span,
5436 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5438 let enum_path_string = path_names_to_string(&enum_path);
5440 (variant_path_string, enum_path_string)
5444 /// When an entity with a given name is not available in scope, we search for
5445 /// entities with that name in all crates. This method allows outputting the
5446 /// results of this search in a programmer-friendly way
5447 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5448 // This is `None` if all placement locations are inside expansions
5450 candidates: &[ImportSuggestion],
5454 // we want consistent results across executions, but candidates are produced
5455 // by iterating through a hash map, so make sure they are ordered:
5456 let mut path_strings: Vec<_> =
5457 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5458 path_strings.sort();
5460 let better = if better { "better " } else { "" };
5461 let msg_diff = match path_strings.len() {
5462 1 => " is found in another module, you can import it",
5463 _ => "s are found in other modules, you can import them",
5465 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5467 if let Some(span) = span {
5468 for candidate in &mut path_strings {
5469 // produce an additional newline to separate the new use statement
5470 // from the directly following item.
5471 let additional_newline = if found_use {
5476 *candidate = format!("use {};\n{}", candidate, additional_newline);
5479 err.span_suggestions(
5482 path_strings.into_iter(),
5483 Applicability::Unspecified,
5488 for candidate in path_strings {
5490 msg.push_str(&candidate);
5495 /// A somewhat inefficient routine to obtain the name of a module.
5496 fn module_to_string(module: Module<'_>) -> Option<String> {
5497 let mut names = Vec::new();
5499 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5500 if let ModuleKind::Def(_, name) = module.kind {
5501 if let Some(parent) = module.parent {
5502 names.push(Ident::with_empty_ctxt(name));
5503 collect_mod(names, parent);
5506 // danger, shouldn't be ident?
5507 names.push(Ident::from_str("<opaque>"));
5508 collect_mod(names, module.parent.unwrap());
5511 collect_mod(&mut names, module);
5513 if names.is_empty() {
5516 Some(names_to_string(&names.into_iter()
5518 .collect::<Vec<_>>()))
5521 fn err_path_resolution() -> PathResolution {
5522 PathResolution::new(Def::Err)
5525 #[derive(Copy, Clone, Debug)]
5527 /// Do not issue the lint
5530 /// This lint applies to some random path like `impl ::foo::Bar`
5531 /// or whatever. In this case, we can take the span of that path.
5534 /// This lint comes from a `use` statement. In this case, what we
5535 /// care about really is the *root* `use` statement; e.g., if we
5536 /// have nested things like `use a::{b, c}`, we care about the
5538 UsePath { root_id: NodeId, root_span: Span },
5540 /// This is the "trait item" from a fully qualified path. For example,
5541 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5542 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5543 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5547 fn node_id(&self) -> Option<NodeId> {
5549 CrateLint::No => None,
5550 CrateLint::SimplePath(id) |
5551 CrateLint::UsePath { root_id: id, .. } |
5552 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5557 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }