1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
16 #![feature(rustc_diagnostic_macros)]
17 #![feature(slice_sort_by_cached_key)]
23 extern crate syntax_pos;
24 extern crate rustc_errors as errors;
28 extern crate rustc_data_structures;
30 pub use rustc::hir::def::{Namespace, PerNS};
32 use self::TypeParameters::*;
35 use rustc::hir::map::{Definitions, DefCollector};
36 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
37 use rustc::middle::cstore::{CrateStore, CrateLoader};
38 use rustc::session::Session;
40 use rustc::hir::def::*;
41 use rustc::hir::def::Namespace::*;
42 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
44 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
45 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
47 use syntax::codemap::CodeMap;
48 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
49 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
50 use syntax::ext::base::SyntaxExtension;
51 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
52 use syntax::ext::base::MacroKind;
53 use syntax::symbol::{Symbol, keywords};
54 use syntax::util::lev_distance::find_best_match_for_name;
56 use syntax::visit::{self, FnKind, Visitor};
58 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
59 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
60 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
61 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
62 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
63 use syntax::feature_gate::{feature_err, GateIssue};
66 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
67 use errors::{DiagnosticBuilder, DiagnosticId};
69 use std::cell::{Cell, RefCell};
71 use std::collections::BTreeSet;
74 use std::mem::replace;
75 use rustc_data_structures::sync::Lrc;
77 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
78 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
80 // NB: This module needs to be declared first so diagnostics are
81 // registered before they are used.
86 mod build_reduced_graph;
89 fn is_known_tool(name: Name) -> bool {
90 ["clippy", "rustfmt"].contains(&&*name.as_str())
93 /// A free importable items suggested in case of resolution failure.
94 struct ImportSuggestion {
98 /// A field or associated item from self type suggested in case of resolution failure.
99 enum AssocSuggestion {
106 struct BindingError {
108 origin: BTreeSet<Span>,
109 target: BTreeSet<Span>,
112 impl PartialOrd for BindingError {
113 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
114 Some(self.cmp(other))
118 impl PartialEq for BindingError {
119 fn eq(&self, other: &BindingError) -> bool {
120 self.name == other.name
124 impl Ord for BindingError {
125 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
126 self.name.cmp(&other.name)
130 enum ResolutionError<'a> {
131 /// error E0401: can't use type parameters from outer function
132 TypeParametersFromOuterFunction(Def),
133 /// error E0403: the name is already used for a type parameter in this type parameter list
134 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
135 /// error E0407: method is not a member of trait
136 MethodNotMemberOfTrait(Name, &'a str),
137 /// error E0437: type is not a member of trait
138 TypeNotMemberOfTrait(Name, &'a str),
139 /// error E0438: const is not a member of trait
140 ConstNotMemberOfTrait(Name, &'a str),
141 /// error E0408: variable `{}` is not bound in all patterns
142 VariableNotBoundInPattern(&'a BindingError),
143 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
144 VariableBoundWithDifferentMode(Name, Span),
145 /// error E0415: identifier is bound more than once in this parameter list
146 IdentifierBoundMoreThanOnceInParameterList(&'a str),
147 /// error E0416: identifier is bound more than once in the same pattern
148 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
149 /// error E0426: use of undeclared label
150 UndeclaredLabel(&'a str, Option<Name>),
151 /// error E0429: `self` imports are only allowed within a { } list
152 SelfImportsOnlyAllowedWithin,
153 /// error E0430: `self` import can only appear once in the list
154 SelfImportCanOnlyAppearOnceInTheList,
155 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
156 SelfImportOnlyInImportListWithNonEmptyPrefix,
157 /// error E0432: unresolved import
158 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
159 /// error E0433: failed to resolve
160 FailedToResolve(&'a str),
161 /// error E0434: can't capture dynamic environment in a fn item
162 CannotCaptureDynamicEnvironmentInFnItem,
163 /// error E0435: attempt to use a non-constant value in a constant
164 AttemptToUseNonConstantValueInConstant,
165 /// error E0530: X bindings cannot shadow Ys
166 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
167 /// error E0128: type parameters with a default cannot use forward declared identifiers
168 ForwardDeclaredTyParam,
171 /// Combines an error with provided span and emits it
173 /// This takes the error provided, combines it with the span and any additional spans inside the
174 /// error and emits it.
175 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
177 resolution_error: ResolutionError<'a>) {
178 resolve_struct_error(resolver, span, resolution_error).emit();
181 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
183 resolution_error: ResolutionError<'a>)
184 -> DiagnosticBuilder<'sess> {
185 match resolution_error {
186 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
187 let mut err = struct_span_err!(resolver.session,
190 "can't use type parameters from outer function");
191 err.span_label(span, "use of type variable from outer function");
193 let cm = resolver.session.codemap();
195 Def::SelfTy(_, maybe_impl_defid) => {
196 if let Some(impl_span) = maybe_impl_defid.map_or(None,
197 |def_id| resolver.definitions.opt_span(def_id)) {
198 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
199 "`Self` type implicitely declared here, on the `impl`");
202 Def::TyParam(typaram_defid) => {
203 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
204 err.span_label(typaram_span, "type variable from outer function");
208 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
213 // Try to retrieve the span of the function signature and generate a new message with
214 // a local type parameter
215 let sugg_msg = "try using a local type parameter instead";
216 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
217 // Suggest the modification to the user
218 err.span_suggestion(sugg_span,
221 } else if let Some(sp) = cm.generate_fn_name_span(span) {
222 err.span_label(sp, "try adding a local type parameter in this method instead");
224 err.help("try using a local type parameter instead");
229 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
230 let mut err = struct_span_err!(resolver.session,
233 "the name `{}` is already used for a type parameter \
234 in this type parameter list",
236 err.span_label(span, "already used");
237 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
240 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
241 let mut err = struct_span_err!(resolver.session,
244 "method `{}` is not a member of trait `{}`",
247 err.span_label(span, format!("not a member of trait `{}`", trait_));
250 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
251 let mut err = struct_span_err!(resolver.session,
254 "type `{}` is not a member of trait `{}`",
257 err.span_label(span, format!("not a member of trait `{}`", trait_));
260 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
261 let mut err = struct_span_err!(resolver.session,
264 "const `{}` is not a member of trait `{}`",
267 err.span_label(span, format!("not a member of trait `{}`", trait_));
270 ResolutionError::VariableNotBoundInPattern(binding_error) => {
271 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
272 let msp = MultiSpan::from_spans(target_sp.clone());
273 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
274 let mut err = resolver.session.struct_span_err_with_code(
277 DiagnosticId::Error("E0408".into()),
279 for sp in target_sp {
280 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
282 let origin_sp = binding_error.origin.iter().cloned();
283 for sp in origin_sp {
284 err.span_label(sp, "variable not in all patterns");
288 ResolutionError::VariableBoundWithDifferentMode(variable_name,
289 first_binding_span) => {
290 let mut err = struct_span_err!(resolver.session,
293 "variable `{}` is bound in inconsistent \
294 ways within the same match arm",
296 err.span_label(span, "bound in different ways");
297 err.span_label(first_binding_span, "first binding");
300 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
301 let mut err = struct_span_err!(resolver.session,
304 "identifier `{}` is bound more than once in this parameter list",
306 err.span_label(span, "used as parameter more than once");
309 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
310 let mut err = struct_span_err!(resolver.session,
313 "identifier `{}` is bound more than once in the same pattern",
315 err.span_label(span, "used in a pattern more than once");
318 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
319 let mut err = struct_span_err!(resolver.session,
322 "use of undeclared label `{}`",
324 if let Some(lev_candidate) = lev_candidate {
325 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
327 err.span_label(span, format!("undeclared label `{}`", name));
331 ResolutionError::SelfImportsOnlyAllowedWithin => {
332 struct_span_err!(resolver.session,
336 "`self` imports are only allowed within a { } list")
338 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
339 let mut err = struct_span_err!(resolver.session, span, E0430,
340 "`self` import can only appear once in an import list");
341 err.span_label(span, "can only appear once in an import list");
344 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
345 let mut err = struct_span_err!(resolver.session, span, E0431,
346 "`self` import can only appear in an import list with \
347 a non-empty prefix");
348 err.span_label(span, "can only appear in an import list with a non-empty prefix");
351 ResolutionError::UnresolvedImport(name) => {
352 let (span, msg) = match name {
353 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
354 None => (span, "unresolved import".to_owned()),
356 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
357 if let Some((_, _, p)) = name {
358 err.span_label(span, p);
362 ResolutionError::FailedToResolve(msg) => {
363 let mut err = struct_span_err!(resolver.session, span, E0433,
364 "failed to resolve. {}", msg);
365 err.span_label(span, msg);
368 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
369 let mut err = struct_span_err!(resolver.session,
373 "can't capture dynamic environment in a fn item");
374 err.help("use the `|| { ... }` closure form instead");
377 ResolutionError::AttemptToUseNonConstantValueInConstant => {
378 let mut err = struct_span_err!(resolver.session, span, E0435,
379 "attempt to use a non-constant value in a constant");
380 err.span_label(span, "non-constant value");
383 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
384 let shadows_what = PathResolution::new(binding.def()).kind_name();
385 let mut err = struct_span_err!(resolver.session,
388 "{}s cannot shadow {}s", what_binding, shadows_what);
389 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
390 let participle = if binding.is_import() { "imported" } else { "defined" };
391 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
392 err.span_label(binding.span, msg);
395 ResolutionError::ForwardDeclaredTyParam => {
396 let mut err = struct_span_err!(resolver.session, span, E0128,
397 "type parameters with a default cannot use \
398 forward declared identifiers");
400 span, "defaulted type parameters cannot be forward declared".to_string());
406 /// Adjust the impl span so that just the `impl` keyword is taken by removing
407 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
408 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
410 /// Attention: The method used is very fragile since it essentially duplicates the work of the
411 /// parser. If you need to use this function or something similar, please consider updating the
412 /// codemap functions and this function to something more robust.
413 fn reduce_impl_span_to_impl_keyword(cm: &CodeMap, impl_span: Span) -> Span {
414 let impl_span = cm.span_until_char(impl_span, '<');
415 let impl_span = cm.span_until_whitespace(impl_span);
419 #[derive(Copy, Clone, Debug)]
422 binding_mode: BindingMode,
425 /// Map from the name in a pattern to its binding mode.
426 type BindingMap = FxHashMap<Ident, BindingInfo>;
428 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
439 fn descr(self) -> &'static str {
441 PatternSource::Match => "match binding",
442 PatternSource::IfLet => "if let binding",
443 PatternSource::WhileLet => "while let binding",
444 PatternSource::Let => "let binding",
445 PatternSource::For => "for binding",
446 PatternSource::FnParam => "function parameter",
451 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
452 enum AliasPossibility {
457 #[derive(Copy, Clone, Debug)]
458 enum PathSource<'a> {
459 // Type paths `Path`.
461 // Trait paths in bounds or impls.
462 Trait(AliasPossibility),
463 // Expression paths `path`, with optional parent context.
464 Expr(Option<&'a Expr>),
465 // Paths in path patterns `Path`.
467 // Paths in struct expressions and patterns `Path { .. }`.
469 // Paths in tuple struct patterns `Path(..)`.
471 // `m::A::B` in `<T as m::A>::B::C`.
472 TraitItem(Namespace),
473 // Path in `pub(path)`
475 // Path in `use a::b::{...};`
479 impl<'a> PathSource<'a> {
480 fn namespace(self) -> Namespace {
482 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
483 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
484 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
485 PathSource::TraitItem(ns) => ns,
489 fn global_by_default(self) -> bool {
491 PathSource::Visibility | PathSource::ImportPrefix => true,
492 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
493 PathSource::Struct | PathSource::TupleStruct |
494 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
498 fn defer_to_typeck(self) -> bool {
500 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
501 PathSource::Struct | PathSource::TupleStruct => true,
502 PathSource::Trait(_) | PathSource::TraitItem(..) |
503 PathSource::Visibility | PathSource::ImportPrefix => false,
507 fn descr_expected(self) -> &'static str {
509 PathSource::Type => "type",
510 PathSource::Trait(_) => "trait",
511 PathSource::Pat => "unit struct/variant or constant",
512 PathSource::Struct => "struct, variant or union type",
513 PathSource::TupleStruct => "tuple struct/variant",
514 PathSource::Visibility => "module",
515 PathSource::ImportPrefix => "module or enum",
516 PathSource::TraitItem(ns) => match ns {
517 TypeNS => "associated type",
518 ValueNS => "method or associated constant",
519 MacroNS => bug!("associated macro"),
521 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
522 // "function" here means "anything callable" rather than `Def::Fn`,
523 // this is not precise but usually more helpful than just "value".
524 Some(&ExprKind::Call(..)) => "function",
530 fn is_expected(self, def: Def) -> bool {
532 PathSource::Type => match def {
533 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
534 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
535 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
536 Def::Existential(..) |
537 Def::TyForeign(..) => true,
540 PathSource::Trait(AliasPossibility::No) => match def {
541 Def::Trait(..) => true,
544 PathSource::Trait(AliasPossibility::Maybe) => match def {
545 Def::Trait(..) => true,
546 Def::TraitAlias(..) => true,
549 PathSource::Expr(..) => match def {
550 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
551 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
552 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
553 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
556 PathSource::Pat => match def {
557 Def::StructCtor(_, CtorKind::Const) |
558 Def::VariantCtor(_, CtorKind::Const) |
559 Def::Const(..) | Def::AssociatedConst(..) => true,
562 PathSource::TupleStruct => match def {
563 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
566 PathSource::Struct => match def {
567 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
568 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
571 PathSource::TraitItem(ns) => match def {
572 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
573 Def::AssociatedTy(..) if ns == TypeNS => true,
576 PathSource::ImportPrefix => match def {
577 Def::Mod(..) | Def::Enum(..) => true,
580 PathSource::Visibility => match def {
581 Def::Mod(..) => true,
587 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
588 __diagnostic_used!(E0404);
589 __diagnostic_used!(E0405);
590 __diagnostic_used!(E0412);
591 __diagnostic_used!(E0422);
592 __diagnostic_used!(E0423);
593 __diagnostic_used!(E0425);
594 __diagnostic_used!(E0531);
595 __diagnostic_used!(E0532);
596 __diagnostic_used!(E0573);
597 __diagnostic_used!(E0574);
598 __diagnostic_used!(E0575);
599 __diagnostic_used!(E0576);
600 __diagnostic_used!(E0577);
601 __diagnostic_used!(E0578);
602 match (self, has_unexpected_resolution) {
603 (PathSource::Trait(_), true) => "E0404",
604 (PathSource::Trait(_), false) => "E0405",
605 (PathSource::Type, true) => "E0573",
606 (PathSource::Type, false) => "E0412",
607 (PathSource::Struct, true) => "E0574",
608 (PathSource::Struct, false) => "E0422",
609 (PathSource::Expr(..), true) => "E0423",
610 (PathSource::Expr(..), false) => "E0425",
611 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
612 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
613 (PathSource::TraitItem(..), true) => "E0575",
614 (PathSource::TraitItem(..), false) => "E0576",
615 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
616 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
621 struct UsePlacementFinder {
622 target_module: NodeId,
627 impl UsePlacementFinder {
628 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
629 let mut finder = UsePlacementFinder {
634 visit::walk_crate(&mut finder, krate);
635 (finder.span, finder.found_use)
639 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
642 module: &'tcx ast::Mod,
644 _: &[ast::Attribute],
647 if self.span.is_some() {
650 if node_id != self.target_module {
651 visit::walk_mod(self, module);
654 // find a use statement
655 for item in &module.items {
657 ItemKind::Use(..) => {
658 // don't suggest placing a use before the prelude
659 // import or other generated ones
660 if item.span.ctxt().outer().expn_info().is_none() {
661 self.span = Some(item.span.shrink_to_lo());
662 self.found_use = true;
666 // don't place use before extern crate
667 ItemKind::ExternCrate(_) => {}
668 // but place them before the first other item
669 _ => if self.span.map_or(true, |span| item.span < span ) {
670 if item.span.ctxt().outer().expn_info().is_none() {
671 // don't insert between attributes and an item
672 if item.attrs.is_empty() {
673 self.span = Some(item.span.shrink_to_lo());
675 // find the first attribute on the item
676 for attr in &item.attrs {
677 if self.span.map_or(true, |span| attr.span < span) {
678 self.span = Some(attr.span.shrink_to_lo());
689 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
690 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
691 fn visit_item(&mut self, item: &'tcx Item) {
692 self.resolve_item(item);
694 fn visit_arm(&mut self, arm: &'tcx Arm) {
695 self.resolve_arm(arm);
697 fn visit_block(&mut self, block: &'tcx Block) {
698 self.resolve_block(block);
700 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
701 self.with_constant_rib(|this| {
702 visit::walk_anon_const(this, constant);
705 fn visit_expr(&mut self, expr: &'tcx Expr) {
706 self.resolve_expr(expr, None);
708 fn visit_local(&mut self, local: &'tcx Local) {
709 self.resolve_local(local);
711 fn visit_ty(&mut self, ty: &'tcx Ty) {
713 TyKind::Path(ref qself, ref path) => {
714 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
716 TyKind::ImplicitSelf => {
717 let self_ty = keywords::SelfType.ident();
718 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
719 .map_or(Def::Err, |d| d.def());
720 self.record_def(ty.id, PathResolution::new(def));
724 visit::walk_ty(self, ty);
726 fn visit_poly_trait_ref(&mut self,
727 tref: &'tcx ast::PolyTraitRef,
728 m: &'tcx ast::TraitBoundModifier) {
729 self.smart_resolve_path(tref.trait_ref.ref_id, None,
730 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
731 visit::walk_poly_trait_ref(self, tref, m);
733 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
734 let type_parameters = match foreign_item.node {
735 ForeignItemKind::Fn(_, ref generics) => {
736 HasTypeParameters(generics, ItemRibKind)
738 ForeignItemKind::Static(..) => NoTypeParameters,
739 ForeignItemKind::Ty => NoTypeParameters,
740 ForeignItemKind::Macro(..) => NoTypeParameters,
742 self.with_type_parameter_rib(type_parameters, |this| {
743 visit::walk_foreign_item(this, foreign_item);
746 fn visit_fn(&mut self,
747 function_kind: FnKind<'tcx>,
748 declaration: &'tcx FnDecl,
752 let (rib_kind, asyncness) = match function_kind {
753 FnKind::ItemFn(_, ref header, ..) =>
754 (ItemRibKind, header.asyncness),
755 FnKind::Method(_, ref sig, _, _) =>
756 (TraitOrImplItemRibKind, sig.header.asyncness),
757 FnKind::Closure(_) =>
758 // Async closures aren't resolved through `visit_fn`-- they're
759 // processed separately
760 (ClosureRibKind(node_id), IsAsync::NotAsync),
763 // Create a value rib for the function.
764 self.ribs[ValueNS].push(Rib::new(rib_kind));
766 // Create a label rib for the function.
767 self.label_ribs.push(Rib::new(rib_kind));
769 // Add each argument to the rib.
770 let mut bindings_list = FxHashMap();
771 for argument in &declaration.inputs {
772 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
774 self.visit_ty(&argument.ty);
776 debug!("(resolving function) recorded argument");
778 visit::walk_fn_ret_ty(self, &declaration.output);
780 // Resolve the function body, potentially inside the body of an async closure
781 if let IsAsync::Async { closure_id, .. } = asyncness {
782 let rib_kind = ClosureRibKind(closure_id);
783 self.ribs[ValueNS].push(Rib::new(rib_kind));
784 self.label_ribs.push(Rib::new(rib_kind));
787 match function_kind {
788 FnKind::ItemFn(.., body) |
789 FnKind::Method(.., body) => {
790 self.visit_block(body);
792 FnKind::Closure(body) => {
793 self.visit_expr(body);
797 // Leave the body of the async closure
798 if asyncness.is_async() {
799 self.label_ribs.pop();
800 self.ribs[ValueNS].pop();
803 debug!("(resolving function) leaving function");
805 self.label_ribs.pop();
806 self.ribs[ValueNS].pop();
808 fn visit_generics(&mut self, generics: &'tcx Generics) {
809 // For type parameter defaults, we have to ban access
810 // to following type parameters, as the Substs can only
811 // provide previous type parameters as they're built. We
812 // put all the parameters on the ban list and then remove
813 // them one by one as they are processed and become available.
814 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
815 let mut found_default = false;
816 default_ban_rib.bindings.extend(generics.params.iter()
817 .filter_map(|param| match param.kind {
818 GenericParamKind::Lifetime { .. } => None,
819 GenericParamKind::Type { ref default, .. } => {
820 if found_default || default.is_some() {
821 found_default = true;
822 return Some((Ident::with_empty_ctxt(param.ident.name), Def::Err));
828 for param in &generics.params {
830 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
831 GenericParamKind::Type { ref default, .. } => {
832 for bound in ¶m.bounds {
833 self.visit_param_bound(bound);
836 if let Some(ref ty) = default {
837 self.ribs[TypeNS].push(default_ban_rib);
839 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
842 // Allow all following defaults to refer to this type parameter.
843 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
847 for p in &generics.where_clause.predicates {
848 self.visit_where_predicate(p);
853 #[derive(Copy, Clone)]
854 enum TypeParameters<'a, 'b> {
856 HasTypeParameters(// Type parameters.
859 // The kind of the rib used for type parameters.
863 /// The rib kind controls the translation of local
864 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
865 #[derive(Copy, Clone, Debug)]
867 /// No translation needs to be applied.
870 /// We passed through a closure scope at the given node ID.
871 /// Translate upvars as appropriate.
872 ClosureRibKind(NodeId /* func id */),
874 /// We passed through an impl or trait and are now in one of its
875 /// methods or associated types. Allow references to ty params that impl or trait
876 /// binds. Disallow any other upvars (including other ty params that are
878 TraitOrImplItemRibKind,
880 /// We passed through an item scope. Disallow upvars.
883 /// We're in a constant item. Can't refer to dynamic stuff.
886 /// We passed through a module.
887 ModuleRibKind(Module<'a>),
889 /// We passed through a `macro_rules!` statement
890 MacroDefinition(DefId),
892 /// All bindings in this rib are type parameters that can't be used
893 /// from the default of a type parameter because they're not declared
894 /// before said type parameter. Also see the `visit_generics` override.
895 ForwardTyParamBanRibKind,
900 /// A rib represents a scope names can live in. Note that these appear in many places, not just
901 /// around braces. At any place where the list of accessible names (of the given namespace)
902 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
903 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
906 /// Different [rib kinds](enum.RibKind) are transparent for different names.
908 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
909 /// resolving, the name is looked up from inside out.
912 bindings: FxHashMap<Ident, Def>,
917 fn new(kind: RibKind<'a>) -> Rib<'a> {
919 bindings: FxHashMap(),
925 /// An intermediate resolution result.
927 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
928 /// items are visible in their whole block, while defs only from the place they are defined
930 enum LexicalScopeBinding<'a> {
931 Item(&'a NameBinding<'a>),
935 impl<'a> LexicalScopeBinding<'a> {
936 fn item(self) -> Option<&'a NameBinding<'a>> {
938 LexicalScopeBinding::Item(binding) => Some(binding),
943 fn def(self) -> Def {
945 LexicalScopeBinding::Item(binding) => binding.def(),
946 LexicalScopeBinding::Def(def) => def,
951 #[derive(Clone, Debug)]
952 enum PathResult<'a> {
954 NonModule(PathResolution),
956 Failed(Span, String, bool /* is the error from the last segment? */),
960 /// An anonymous module, eg. just a block.
965 /// { // This is an anonymous module
966 /// f(); // This resolves to (2) as we are inside the block.
969 /// f(); // Resolves to (1)
973 /// Any module with a name.
977 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
978 /// * A trait or an enum (it implicitly contains associated types, methods and variant
983 /// One node in the tree of modules.
984 pub struct ModuleData<'a> {
985 parent: Option<Module<'a>>,
988 // The def id of the closest normal module (`mod`) ancestor (including this module).
989 normal_ancestor_id: DefId,
991 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
992 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, MacroKind, Option<Def>)>>,
993 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
995 // Macro invocations that can expand into items in this module.
996 unresolved_invocations: RefCell<FxHashSet<Mark>>,
998 no_implicit_prelude: bool,
1000 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1001 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1003 // Used to memoize the traits in this module for faster searches through all traits in scope.
1004 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1006 // Whether this module is populated. If not populated, any attempt to
1007 // access the children must be preceded with a
1008 // `populate_module_if_necessary` call.
1009 populated: Cell<bool>,
1011 /// Span of the module itself. Used for error reporting.
1017 type Module<'a> = &'a ModuleData<'a>;
1019 impl<'a> ModuleData<'a> {
1020 fn new(parent: Option<Module<'a>>,
1022 normal_ancestor_id: DefId,
1024 span: Span) -> Self {
1029 resolutions: RefCell::new(FxHashMap()),
1030 legacy_macro_resolutions: RefCell::new(Vec::new()),
1031 macro_resolutions: RefCell::new(Vec::new()),
1032 unresolved_invocations: RefCell::new(FxHashSet()),
1033 no_implicit_prelude: false,
1034 glob_importers: RefCell::new(Vec::new()),
1035 globs: RefCell::new(Vec::new()),
1036 traits: RefCell::new(None),
1037 populated: Cell::new(normal_ancestor_id.is_local()),
1043 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1044 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1045 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1049 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1050 let resolutions = self.resolutions.borrow();
1051 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1052 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1053 for &(&(ident, ns), &resolution) in resolutions.iter() {
1054 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1058 fn def(&self) -> Option<Def> {
1060 ModuleKind::Def(def, _) => Some(def),
1065 fn def_id(&self) -> Option<DefId> {
1066 self.def().as_ref().map(Def::def_id)
1069 // `self` resolves to the first module ancestor that `is_normal`.
1070 fn is_normal(&self) -> bool {
1072 ModuleKind::Def(Def::Mod(_), _) => true,
1077 fn is_trait(&self) -> bool {
1079 ModuleKind::Def(Def::Trait(_), _) => true,
1084 fn is_local(&self) -> bool {
1085 self.normal_ancestor_id.is_local()
1088 fn nearest_item_scope(&'a self) -> Module<'a> {
1089 if self.is_trait() { self.parent.unwrap() } else { self }
1093 impl<'a> fmt::Debug for ModuleData<'a> {
1094 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1095 write!(f, "{:?}", self.def())
1099 /// Records a possibly-private value, type, or module definition.
1100 #[derive(Clone, Debug)]
1101 pub struct NameBinding<'a> {
1102 kind: NameBindingKind<'a>,
1105 vis: ty::Visibility,
1108 pub trait ToNameBinding<'a> {
1109 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1112 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1113 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1118 #[derive(Clone, Debug)]
1119 enum NameBindingKind<'a> {
1120 Def(Def, /* is_macro_export */ bool),
1123 binding: &'a NameBinding<'a>,
1124 directive: &'a ImportDirective<'a>,
1128 b1: &'a NameBinding<'a>,
1129 b2: &'a NameBinding<'a>,
1133 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1135 struct UseError<'a> {
1136 err: DiagnosticBuilder<'a>,
1137 /// Attach `use` statements for these candidates
1138 candidates: Vec<ImportSuggestion>,
1139 /// The node id of the module to place the use statements in
1141 /// Whether the diagnostic should state that it's "better"
1145 struct AmbiguityError<'a> {
1149 b1: &'a NameBinding<'a>,
1150 b2: &'a NameBinding<'a>,
1153 impl<'a> NameBinding<'a> {
1154 fn module(&self) -> Option<Module<'a>> {
1156 NameBindingKind::Module(module) => Some(module),
1157 NameBindingKind::Import { binding, .. } => binding.module(),
1162 fn def(&self) -> Def {
1164 NameBindingKind::Def(def, _) => def,
1165 NameBindingKind::Module(module) => module.def().unwrap(),
1166 NameBindingKind::Import { binding, .. } => binding.def(),
1167 NameBindingKind::Ambiguity { .. } => Def::Err,
1171 fn def_ignoring_ambiguity(&self) -> Def {
1173 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1174 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1179 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Lrc<SyntaxExtension> {
1180 resolver.get_macro(self.def_ignoring_ambiguity())
1183 // We sometimes need to treat variants as `pub` for backwards compatibility
1184 fn pseudo_vis(&self) -> ty::Visibility {
1185 if self.is_variant() && self.def().def_id().is_local() {
1186 ty::Visibility::Public
1192 fn is_variant(&self) -> bool {
1194 NameBindingKind::Def(Def::Variant(..), _) |
1195 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1200 fn is_extern_crate(&self) -> bool {
1202 NameBindingKind::Import {
1203 directive: &ImportDirective {
1204 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1211 fn is_import(&self) -> bool {
1213 NameBindingKind::Import { .. } => true,
1218 fn is_renamed_extern_crate(&self) -> bool {
1219 if let NameBindingKind::Import { directive, ..} = self.kind {
1220 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1227 fn is_glob_import(&self) -> bool {
1229 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1230 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1235 fn is_importable(&self) -> bool {
1237 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1242 fn is_macro_def(&self) -> bool {
1244 NameBindingKind::Def(Def::Macro(..), _) => true,
1249 fn descr(&self) -> &'static str {
1250 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1254 /// Interns the names of the primitive types.
1256 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1257 /// special handling, since they have no place of origin.
1258 struct PrimitiveTypeTable {
1259 primitive_types: FxHashMap<Name, PrimTy>,
1262 impl PrimitiveTypeTable {
1263 fn new() -> PrimitiveTypeTable {
1264 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1266 table.intern("bool", TyBool);
1267 table.intern("char", TyChar);
1268 table.intern("f32", TyFloat(FloatTy::F32));
1269 table.intern("f64", TyFloat(FloatTy::F64));
1270 table.intern("isize", TyInt(IntTy::Isize));
1271 table.intern("i8", TyInt(IntTy::I8));
1272 table.intern("i16", TyInt(IntTy::I16));
1273 table.intern("i32", TyInt(IntTy::I32));
1274 table.intern("i64", TyInt(IntTy::I64));
1275 table.intern("i128", TyInt(IntTy::I128));
1276 table.intern("str", TyStr);
1277 table.intern("usize", TyUint(UintTy::Usize));
1278 table.intern("u8", TyUint(UintTy::U8));
1279 table.intern("u16", TyUint(UintTy::U16));
1280 table.intern("u32", TyUint(UintTy::U32));
1281 table.intern("u64", TyUint(UintTy::U64));
1282 table.intern("u128", TyUint(UintTy::U128));
1286 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1287 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1291 /// The main resolver class.
1293 /// This is the visitor that walks the whole crate.
1294 pub struct Resolver<'a> {
1295 session: &'a Session,
1296 cstore: &'a dyn CrateStore,
1298 pub definitions: Definitions,
1300 graph_root: Module<'a>,
1302 prelude: Option<Module<'a>>,
1303 extern_prelude: FxHashSet<Name>,
1305 /// n.b. This is used only for better diagnostics, not name resolution itself.
1306 has_self: FxHashSet<DefId>,
1308 /// Names of fields of an item `DefId` accessible with dot syntax.
1309 /// Used for hints during error reporting.
1310 field_names: FxHashMap<DefId, Vec<Name>>,
1312 /// All imports known to succeed or fail.
1313 determined_imports: Vec<&'a ImportDirective<'a>>,
1315 /// All non-determined imports.
1316 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1318 /// The module that represents the current item scope.
1319 current_module: Module<'a>,
1321 /// The current set of local scopes for types and values.
1322 /// FIXME #4948: Reuse ribs to avoid allocation.
1323 ribs: PerNS<Vec<Rib<'a>>>,
1325 /// The current set of local scopes, for labels.
1326 label_ribs: Vec<Rib<'a>>,
1328 /// The trait that the current context can refer to.
1329 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1331 /// The current self type if inside an impl (used for better errors).
1332 current_self_type: Option<Ty>,
1334 /// The idents for the primitive types.
1335 primitive_type_table: PrimitiveTypeTable,
1338 import_map: ImportMap,
1339 pub freevars: FreevarMap,
1340 freevars_seen: NodeMap<NodeMap<usize>>,
1341 pub export_map: ExportMap,
1342 pub trait_map: TraitMap,
1344 /// A map from nodes to anonymous modules.
1345 /// Anonymous modules are pseudo-modules that are implicitly created around items
1346 /// contained within blocks.
1348 /// For example, if we have this:
1356 /// There will be an anonymous module created around `g` with the ID of the
1357 /// entry block for `f`.
1358 block_map: NodeMap<Module<'a>>,
1359 module_map: FxHashMap<DefId, Module<'a>>,
1360 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1362 pub make_glob_map: bool,
1363 /// Maps imports to the names of items actually imported (this actually maps
1364 /// all imports, but only glob imports are actually interesting).
1365 pub glob_map: GlobMap,
1367 used_imports: FxHashSet<(NodeId, Namespace)>,
1368 pub maybe_unused_trait_imports: NodeSet,
1369 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1371 /// A list of labels as of yet unused. Labels will be removed from this map when
1372 /// they are used (in a `break` or `continue` statement)
1373 pub unused_labels: FxHashMap<NodeId, Span>,
1375 /// privacy errors are delayed until the end in order to deduplicate them
1376 privacy_errors: Vec<PrivacyError<'a>>,
1377 /// ambiguity errors are delayed for deduplication
1378 ambiguity_errors: Vec<AmbiguityError<'a>>,
1379 /// `use` injections are delayed for better placement and deduplication
1380 use_injections: Vec<UseError<'a>>,
1381 /// `use` injections for proc macros wrongly imported with #[macro_use]
1382 proc_mac_errors: Vec<macros::ProcMacError>,
1384 gated_errors: FxHashSet<Span>,
1385 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1387 arenas: &'a ResolverArenas<'a>,
1388 dummy_binding: &'a NameBinding<'a>,
1389 /// true if `#![feature(use_extern_macros)]`
1390 use_extern_macros: bool,
1392 crate_loader: &'a mut dyn CrateLoader,
1393 macro_names: FxHashSet<Ident>,
1394 macro_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1395 pub all_macros: FxHashMap<Name, Def>,
1396 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1397 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1398 macro_defs: FxHashMap<Mark, DefId>,
1399 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1400 macro_exports: Vec<Export>, // FIXME: Remove when `use_extern_macros` is stabilized
1401 pub whitelisted_legacy_custom_derives: Vec<Name>,
1402 pub found_unresolved_macro: bool,
1404 /// List of crate local macros that we need to warn about as being unused.
1405 /// Right now this only includes macro_rules! macros, and macros 2.0.
1406 unused_macros: FxHashSet<DefId>,
1408 /// Maps the `Mark` of an expansion to its containing module or block.
1409 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1411 /// Avoid duplicated errors for "name already defined".
1412 name_already_seen: FxHashMap<Name, Span>,
1414 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1415 warned_proc_macros: FxHashSet<Name>,
1417 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1419 /// This table maps struct IDs into struct constructor IDs,
1420 /// it's not used during normal resolution, only for better error reporting.
1421 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1423 /// Only used for better errors on `fn(): fn()`
1424 current_type_ascription: Vec<Span>,
1426 injected_crate: Option<Module<'a>>,
1428 /// Only supposed to be used by rustdoc, otherwise should be false.
1429 pub ignore_extern_prelude_feature: bool,
1431 /// Macro invocations in the whole crate that can expand into a `#[macro_export] macro_rules`.
1432 unresolved_invocations_macro_export: FxHashSet<Mark>,
1435 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1436 pub struct ResolverArenas<'a> {
1437 modules: arena::TypedArena<ModuleData<'a>>,
1438 local_modules: RefCell<Vec<Module<'a>>>,
1439 name_bindings: arena::TypedArena<NameBinding<'a>>,
1440 import_directives: arena::TypedArena<ImportDirective<'a>>,
1441 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1442 invocation_data: arena::TypedArena<InvocationData<'a>>,
1443 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1446 impl<'a> ResolverArenas<'a> {
1447 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1448 let module = self.modules.alloc(module);
1449 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1450 self.local_modules.borrow_mut().push(module);
1454 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1455 self.local_modules.borrow()
1457 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1458 self.name_bindings.alloc(name_binding)
1460 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1461 -> &'a ImportDirective {
1462 self.import_directives.alloc(import_directive)
1464 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1465 self.name_resolutions.alloc(Default::default())
1467 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1468 -> &'a InvocationData<'a> {
1469 self.invocation_data.alloc(expansion_data)
1471 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1472 self.legacy_bindings.alloc(binding)
1476 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1477 fn parent(self, id: DefId) -> Option<DefId> {
1479 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1480 _ => self.cstore.def_key(id).parent,
1481 }.map(|index| DefId { index, ..id })
1485 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1486 /// the resolver is no longer needed as all the relevant information is inline.
1487 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1488 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1489 self.resolve_hir_path_cb(path, is_value,
1490 |resolver, span, error| resolve_error(resolver, span, error))
1493 fn resolve_str_path(
1496 crate_root: Option<&str>,
1497 components: &[&str],
1498 args: Option<P<hir::GenericArgs>>,
1501 let mut segments = iter::once(keywords::CrateRoot.ident())
1503 crate_root.into_iter()
1504 .chain(components.iter().cloned())
1505 .map(Ident::from_str)
1506 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1508 if let Some(args) = args {
1509 let ident = segments.last().unwrap().ident;
1510 *segments.last_mut().unwrap() = hir::PathSegment {
1517 let mut path = hir::Path {
1520 segments: segments.into(),
1523 self.resolve_hir_path(&mut path, is_value);
1527 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1528 self.def_map.get(&id).cloned()
1531 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1532 self.import_map.get(&id).cloned().unwrap_or_default()
1535 fn definitions(&mut self) -> &mut Definitions {
1536 &mut self.definitions
1540 impl<'a> Resolver<'a> {
1541 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1542 /// isn't something that can be returned because it can't be made to live that long,
1543 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1544 /// just that an error occurred.
1545 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1546 -> Result<hir::Path, ()> {
1548 let mut errored = false;
1550 let mut path = if path_str.starts_with("::") {
1554 segments: iter::once(keywords::CrateRoot.ident()).chain({
1555 path_str.split("::").skip(1).map(Ident::from_str)
1556 }).map(hir::PathSegment::from_ident).collect(),
1562 segments: path_str.split("::").map(Ident::from_str)
1563 .map(hir::PathSegment::from_ident).collect(),
1566 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1567 if errored || path.def == Def::Err {
1574 /// resolve_hir_path, but takes a callback in case there was an error
1575 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1576 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1578 let namespace = if is_value { ValueNS } else { TypeNS };
1579 let hir::Path { ref segments, span, ref mut def } = *path;
1580 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1581 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1582 match self.resolve_path(&path, Some(namespace), true, span, CrateLint::No) {
1583 PathResult::Module(module) => *def = module.def().unwrap(),
1584 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1585 *def = path_res.base_def(),
1586 PathResult::NonModule(..) => match self.resolve_path(
1593 PathResult::Failed(span, msg, _) => {
1594 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1598 PathResult::Indeterminate => unreachable!(),
1599 PathResult::Failed(span, msg, _) => {
1600 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1606 impl<'a> Resolver<'a> {
1607 pub fn new(session: &'a Session,
1608 cstore: &'a dyn CrateStore,
1611 make_glob_map: MakeGlobMap,
1612 crate_loader: &'a mut dyn CrateLoader,
1613 arenas: &'a ResolverArenas<'a>)
1615 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1616 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1617 let graph_root = arenas.alloc_module(ModuleData {
1618 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1619 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1621 let mut module_map = FxHashMap();
1622 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1624 let mut definitions = Definitions::new();
1625 DefCollector::new(&mut definitions, Mark::root())
1626 .collect_root(crate_name, session.local_crate_disambiguator());
1628 let mut extern_prelude: FxHashSet<Name> =
1629 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1630 if !attr::contains_name(&krate.attrs, "no_core") {
1631 if !attr::contains_name(&krate.attrs, "no_std") {
1632 extern_prelude.insert(Symbol::intern("std"));
1634 extern_prelude.insert(Symbol::intern("core"));
1638 let mut invocations = FxHashMap();
1639 invocations.insert(Mark::root(),
1640 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1642 let features = session.features_untracked();
1644 let mut macro_defs = FxHashMap();
1645 macro_defs.insert(Mark::root(), root_def_id);
1654 // The outermost module has def ID 0; this is not reflected in the
1660 has_self: FxHashSet(),
1661 field_names: FxHashMap(),
1663 determined_imports: Vec::new(),
1664 indeterminate_imports: Vec::new(),
1666 current_module: graph_root,
1668 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1669 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1670 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1672 label_ribs: Vec::new(),
1674 current_trait_ref: None,
1675 current_self_type: None,
1677 primitive_type_table: PrimitiveTypeTable::new(),
1680 import_map: NodeMap(),
1681 freevars: NodeMap(),
1682 freevars_seen: NodeMap(),
1683 export_map: FxHashMap(),
1684 trait_map: NodeMap(),
1686 block_map: NodeMap(),
1687 extern_module_map: FxHashMap(),
1689 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1690 glob_map: NodeMap(),
1692 used_imports: FxHashSet(),
1693 maybe_unused_trait_imports: NodeSet(),
1694 maybe_unused_extern_crates: Vec::new(),
1696 unused_labels: FxHashMap(),
1698 privacy_errors: Vec::new(),
1699 ambiguity_errors: Vec::new(),
1700 use_injections: Vec::new(),
1701 proc_mac_errors: Vec::new(),
1702 gated_errors: FxHashSet(),
1703 disallowed_shadowing: Vec::new(),
1706 dummy_binding: arenas.alloc_name_binding(NameBinding {
1707 kind: NameBindingKind::Def(Def::Err, false),
1708 expansion: Mark::root(),
1710 vis: ty::Visibility::Public,
1713 use_extern_macros: features.use_extern_macros(),
1716 macro_names: FxHashSet(),
1717 macro_prelude: FxHashMap(),
1718 all_macros: FxHashMap(),
1719 lexical_macro_resolutions: Vec::new(),
1720 macro_map: FxHashMap(),
1721 macro_exports: Vec::new(),
1724 local_macro_def_scopes: FxHashMap(),
1725 name_already_seen: FxHashMap(),
1726 whitelisted_legacy_custom_derives: Vec::new(),
1727 warned_proc_macros: FxHashSet(),
1728 potentially_unused_imports: Vec::new(),
1729 struct_constructors: DefIdMap(),
1730 found_unresolved_macro: false,
1731 unused_macros: FxHashSet(),
1732 current_type_ascription: Vec::new(),
1733 injected_crate: None,
1734 ignore_extern_prelude_feature: false,
1735 unresolved_invocations_macro_export: FxHashSet(),
1739 pub fn arenas() -> ResolverArenas<'a> {
1741 modules: arena::TypedArena::new(),
1742 local_modules: RefCell::new(Vec::new()),
1743 name_bindings: arena::TypedArena::new(),
1744 import_directives: arena::TypedArena::new(),
1745 name_resolutions: arena::TypedArena::new(),
1746 invocation_data: arena::TypedArena::new(),
1747 legacy_bindings: arena::TypedArena::new(),
1751 /// Runs the function on each namespace.
1752 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1755 if self.use_extern_macros {
1760 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1762 match self.macro_defs.get(&ctxt.outer()) {
1763 Some(&def_id) => return def_id,
1764 None => ctxt.remove_mark(),
1769 /// Entry point to crate resolution.
1770 pub fn resolve_crate(&mut self, krate: &Crate) {
1771 ImportResolver { resolver: self }.finalize_imports();
1772 self.current_module = self.graph_root;
1773 self.finalize_current_module_macro_resolutions();
1775 visit::walk_crate(self, krate);
1777 check_unused::check_crate(self, krate);
1778 self.report_errors(krate);
1779 self.crate_loader.postprocess(krate);
1786 normal_ancestor_id: DefId,
1790 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1791 self.arenas.alloc_module(module)
1794 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1795 -> bool /* true if an error was reported */ {
1796 match binding.kind {
1797 NameBindingKind::Import { directive, binding, ref used }
1800 directive.used.set(true);
1801 self.used_imports.insert((directive.id, ns));
1802 self.add_to_glob_map(directive.id, ident);
1803 self.record_use(ident, ns, binding, span)
1805 NameBindingKind::Import { .. } => false,
1806 NameBindingKind::Ambiguity { b1, b2 } => {
1807 self.ambiguity_errors.push(AmbiguityError {
1808 span, name: ident.name, lexical: false, b1, b2,
1816 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1817 if self.make_glob_map {
1818 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1822 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1823 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1824 /// `ident` in the first scope that defines it (or None if no scopes define it).
1826 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1827 /// the items are defined in the block. For example,
1830 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1833 /// g(); // This resolves to the local variable `g` since it shadows the item.
1837 /// Invariant: This must only be called during main resolution, not during
1838 /// import resolution.
1839 fn resolve_ident_in_lexical_scope(&mut self,
1842 record_used_id: Option<NodeId>,
1844 -> Option<LexicalScopeBinding<'a>> {
1845 let record_used = record_used_id.is_some();
1846 assert!(ns == TypeNS || ns == ValueNS);
1848 ident.span = if ident.name == keywords::SelfType.name() {
1849 // FIXME(jseyfried) improve `Self` hygiene
1850 ident.span.with_ctxt(SyntaxContext::empty())
1855 ident = ident.modern_and_legacy();
1858 // Walk backwards up the ribs in scope.
1859 let mut module = self.graph_root;
1860 for i in (0 .. self.ribs[ns].len()).rev() {
1861 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1862 // The ident resolves to a type parameter or local variable.
1863 return Some(LexicalScopeBinding::Def(
1864 self.adjust_local_def(ns, i, def, record_used, path_span)
1868 module = match self.ribs[ns][i].kind {
1869 ModuleRibKind(module) => module,
1870 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1871 // If an invocation of this macro created `ident`, give up on `ident`
1872 // and switch to `ident`'s source from the macro definition.
1873 ident.span.remove_mark();
1879 let item = self.resolve_ident_in_module_unadjusted(
1880 module, ident, ns, false, record_used, path_span,
1882 if let Ok(binding) = item {
1883 // The ident resolves to an item.
1884 return Some(LexicalScopeBinding::Item(binding));
1888 ModuleKind::Block(..) => {}, // We can see through blocks
1893 ident.span = ident.span.modern();
1895 let (opt_module, poisoned) = if let Some(node_id) = record_used_id {
1896 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1899 (self.hygienic_lexical_parent(module, &mut ident.span), None)
1901 module = unwrap_or!(opt_module, break);
1902 let orig_current_module = self.current_module;
1903 self.current_module = module; // Lexical resolutions can never be a privacy error.
1904 let result = self.resolve_ident_in_module_unadjusted(
1905 module, ident, ns, false, record_used, path_span,
1907 self.current_module = orig_current_module;
1911 if let Some(node_id) = poisoned {
1912 self.session.buffer_lint_with_diagnostic(
1913 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1914 node_id, ident.span,
1915 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1916 lint::builtin::BuiltinLintDiagnostics::
1917 ProcMacroDeriveResolutionFallback(ident.span),
1920 return Some(LexicalScopeBinding::Item(binding))
1922 _ if poisoned.is_some() => break,
1923 Err(Determined) => continue,
1924 Err(Undetermined) =>
1925 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1929 if !module.no_implicit_prelude {
1930 // `record_used` means that we don't try to load crates during speculative resolution
1931 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1932 if !self.session.features_untracked().extern_prelude &&
1933 !self.ignore_extern_prelude_feature {
1934 feature_err(&self.session.parse_sess, "extern_prelude",
1935 ident.span, GateIssue::Language,
1936 "access to extern crates through prelude is experimental").emit();
1939 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1940 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1941 self.populate_module_if_necessary(crate_root);
1943 let binding = (crate_root, ty::Visibility::Public,
1944 ident.span, Mark::root()).to_name_binding(self.arenas);
1945 return Some(LexicalScopeBinding::Item(binding));
1947 if ns == TypeNS && is_known_tool(ident.name) {
1948 let binding = (Def::ToolMod, ty::Visibility::Public,
1949 ident.span, Mark::root()).to_name_binding(self.arenas);
1950 return Some(LexicalScopeBinding::Item(binding));
1952 if let Some(prelude) = self.prelude {
1953 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(prelude, ident, ns,
1954 false, false, path_span) {
1955 return Some(LexicalScopeBinding::Item(binding));
1963 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
1964 -> Option<Module<'a>> {
1965 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
1966 return Some(self.macro_def_scope(span.remove_mark()));
1969 if let ModuleKind::Block(..) = module.kind {
1970 return Some(module.parent.unwrap());
1976 fn hygienic_lexical_parent_with_compatibility_fallback(
1977 &mut self, module: Module<'a>, span: &mut Span, node_id: NodeId
1978 ) -> (Option<Module<'a>>, /* poisoned */ Option<NodeId>)
1980 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1981 return (module, None);
1984 // We need to support the next case under a deprecation warning
1987 // ---- begin: this comes from a proc macro derive
1988 // mod implementation_details {
1989 // // Note that `MyStruct` is not in scope here.
1990 // impl SomeTrait for MyStruct { ... }
1994 // So we have to fall back to the module's parent during lexical resolution in this case.
1995 if let Some(parent) = module.parent {
1996 // Inner module is inside the macro, parent module is outside of the macro.
1997 if module.expansion != parent.expansion &&
1998 module.expansion.is_descendant_of(parent.expansion) {
1999 // The macro is a proc macro derive
2000 if module.expansion.looks_like_proc_macro_derive() {
2001 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2002 return (module.parent, Some(node_id));
2011 fn resolve_ident_in_module(&mut self,
2017 -> Result<&'a NameBinding<'a>, Determinacy> {
2018 ident.span = ident.span.modern();
2019 let orig_current_module = self.current_module;
2020 if let Some(def) = ident.span.adjust(module.expansion) {
2021 self.current_module = self.macro_def_scope(def);
2023 let result = self.resolve_ident_in_module_unadjusted(
2024 module, ident, ns, false, record_used, span,
2026 self.current_module = orig_current_module;
2030 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2031 let mut ctxt = ident.span.ctxt();
2032 let mark = if ident.name == keywords::DollarCrate.name() {
2033 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2034 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2035 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2036 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2037 // definitions actually produced by `macro` and `macro` definitions produced by
2038 // `macro_rules!`, but at least such configurations are not stable yet.
2039 ctxt = ctxt.modern_and_legacy();
2040 let mut iter = ctxt.marks().into_iter().rev().peekable();
2041 let mut result = None;
2042 // Find the last modern mark from the end if it exists.
2043 while let Some(&(mark, transparency)) = iter.peek() {
2044 if transparency == Transparency::Opaque {
2045 result = Some(mark);
2051 // Then find the last legacy mark from the end if it exists.
2052 for (mark, transparency) in iter {
2053 if transparency == Transparency::SemiTransparent {
2054 result = Some(mark);
2061 ctxt = ctxt.modern();
2062 ctxt.adjust(Mark::root())
2064 let module = match mark {
2065 Some(def) => self.macro_def_scope(def),
2066 None => return self.graph_root,
2068 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2071 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2072 let mut module = self.get_module(module.normal_ancestor_id);
2073 while module.span.ctxt().modern() != *ctxt {
2074 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2075 module = self.get_module(parent.normal_ancestor_id);
2082 // We maintain a list of value ribs and type ribs.
2084 // Simultaneously, we keep track of the current position in the module
2085 // graph in the `current_module` pointer. When we go to resolve a name in
2086 // the value or type namespaces, we first look through all the ribs and
2087 // then query the module graph. When we resolve a name in the module
2088 // namespace, we can skip all the ribs (since nested modules are not
2089 // allowed within blocks in Rust) and jump straight to the current module
2092 // Named implementations are handled separately. When we find a method
2093 // call, we consult the module node to find all of the implementations in
2094 // scope. This information is lazily cached in the module node. We then
2095 // generate a fake "implementation scope" containing all the
2096 // implementations thus found, for compatibility with old resolve pass.
2098 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2099 where F: FnOnce(&mut Resolver) -> T
2101 let id = self.definitions.local_def_id(id);
2102 let module = self.module_map.get(&id).cloned(); // clones a reference
2103 if let Some(module) = module {
2104 // Move down in the graph.
2105 let orig_module = replace(&mut self.current_module, module);
2106 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2107 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2109 self.finalize_current_module_macro_resolutions();
2112 self.current_module = orig_module;
2113 self.ribs[ValueNS].pop();
2114 self.ribs[TypeNS].pop();
2121 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2122 /// is returned by the given predicate function
2124 /// Stops after meeting a closure.
2125 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2126 where P: Fn(&Rib, Ident) -> Option<R>
2128 for rib in self.label_ribs.iter().rev() {
2131 // If an invocation of this macro created `ident`, give up on `ident`
2132 // and switch to `ident`'s source from the macro definition.
2133 MacroDefinition(def) => {
2134 if def == self.macro_def(ident.span.ctxt()) {
2135 ident.span.remove_mark();
2139 // Do not resolve labels across function boundary
2143 let r = pred(rib, ident);
2151 fn resolve_item(&mut self, item: &Item) {
2152 let name = item.ident.name;
2154 debug!("(resolving item) resolving {}", name);
2156 self.check_proc_macro_attrs(&item.attrs);
2159 ItemKind::Enum(_, ref generics) |
2160 ItemKind::Ty(_, ref generics) |
2161 ItemKind::Existential(_, ref generics) |
2162 ItemKind::Struct(_, ref generics) |
2163 ItemKind::Union(_, ref generics) |
2164 ItemKind::Fn(_, _, ref generics, _) => {
2165 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2166 |this| visit::walk_item(this, item));
2169 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2170 self.resolve_implementation(generics,
2176 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2177 // Create a new rib for the trait-wide type parameters.
2178 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2179 let local_def_id = this.definitions.local_def_id(item.id);
2180 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2181 this.visit_generics(generics);
2182 walk_list!(this, visit_param_bound, bounds);
2184 for trait_item in trait_items {
2185 this.check_proc_macro_attrs(&trait_item.attrs);
2187 let type_parameters = HasTypeParameters(&trait_item.generics,
2188 TraitOrImplItemRibKind);
2189 this.with_type_parameter_rib(type_parameters, |this| {
2190 match trait_item.node {
2191 TraitItemKind::Const(ref ty, ref default) => {
2194 // Only impose the restrictions of
2195 // ConstRibKind for an actual constant
2196 // expression in a provided default.
2197 if let Some(ref expr) = *default{
2198 this.with_constant_rib(|this| {
2199 this.visit_expr(expr);
2203 TraitItemKind::Method(_, _) => {
2204 visit::walk_trait_item(this, trait_item)
2206 TraitItemKind::Type(..) => {
2207 visit::walk_trait_item(this, trait_item)
2209 TraitItemKind::Macro(_) => {
2210 panic!("unexpanded macro in resolve!")
2219 ItemKind::TraitAlias(ref generics, ref bounds) => {
2220 // Create a new rib for the trait-wide type parameters.
2221 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2222 let local_def_id = this.definitions.local_def_id(item.id);
2223 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2224 this.visit_generics(generics);
2225 walk_list!(this, visit_param_bound, bounds);
2230 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2231 self.with_scope(item.id, |this| {
2232 visit::walk_item(this, item);
2236 ItemKind::Static(ref ty, _, ref expr) |
2237 ItemKind::Const(ref ty, ref expr) => {
2238 self.with_item_rib(|this| {
2240 this.with_constant_rib(|this| {
2241 this.visit_expr(expr);
2246 ItemKind::Use(ref use_tree) => {
2247 // Imports are resolved as global by default, add starting root segment.
2249 segments: use_tree.prefix.make_root().into_iter().collect(),
2250 span: use_tree.span,
2252 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2255 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2256 // do nothing, these are just around to be encoded
2259 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2263 /// For the most part, use trees are desugared into `ImportDirective` instances
2264 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2265 /// there is one special case we handle here: an empty nested import like
2266 /// `a::{b::{}}`, which desugares into...no import directives.
2267 fn resolve_use_tree(
2272 use_tree: &ast::UseTree,
2275 match use_tree.kind {
2276 ast::UseTreeKind::Nested(ref items) => {
2278 segments: prefix.segments
2280 .chain(use_tree.prefix.segments.iter())
2283 span: prefix.span.to(use_tree.prefix.span),
2286 if items.len() == 0 {
2287 // Resolve prefix of an import with empty braces (issue #28388).
2288 self.smart_resolve_path_with_crate_lint(
2292 PathSource::ImportPrefix,
2293 CrateLint::UsePath { root_id, root_span },
2296 for &(ref tree, nested_id) in items {
2297 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2301 ast::UseTreeKind::Simple(..) => {},
2302 ast::UseTreeKind::Glob => {},
2306 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2307 where F: FnOnce(&mut Resolver)
2309 match type_parameters {
2310 HasTypeParameters(generics, rib_kind) => {
2311 let mut function_type_rib = Rib::new(rib_kind);
2312 let mut seen_bindings = FxHashMap();
2313 generics.params.iter().for_each(|param| match param.kind {
2314 GenericParamKind::Lifetime { .. } => {}
2315 GenericParamKind::Type { .. } => {
2316 let ident = param.ident.modern();
2317 debug!("with_type_parameter_rib: {}", param.id);
2319 if seen_bindings.contains_key(&ident) {
2320 let span = seen_bindings.get(&ident).unwrap();
2321 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2325 resolve_error(self, param.ident.span, err);
2327 seen_bindings.entry(ident).or_insert(param.ident.span);
2329 // Plain insert (no renaming).
2330 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2331 function_type_rib.bindings.insert(ident, def);
2332 self.record_def(param.id, PathResolution::new(def));
2335 self.ribs[TypeNS].push(function_type_rib);
2338 NoTypeParameters => {
2345 if let HasTypeParameters(..) = type_parameters {
2346 self.ribs[TypeNS].pop();
2350 fn with_label_rib<F>(&mut self, f: F)
2351 where F: FnOnce(&mut Resolver)
2353 self.label_ribs.push(Rib::new(NormalRibKind));
2355 self.label_ribs.pop();
2358 fn with_item_rib<F>(&mut self, f: F)
2359 where F: FnOnce(&mut Resolver)
2361 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2362 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2364 self.ribs[TypeNS].pop();
2365 self.ribs[ValueNS].pop();
2368 fn with_constant_rib<F>(&mut self, f: F)
2369 where F: FnOnce(&mut Resolver)
2371 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2372 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2374 self.label_ribs.pop();
2375 self.ribs[ValueNS].pop();
2378 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2379 where F: FnOnce(&mut Resolver) -> T
2381 // Handle nested impls (inside fn bodies)
2382 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2383 let result = f(self);
2384 self.current_self_type = previous_value;
2388 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2389 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2390 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2392 let mut new_val = None;
2393 let mut new_id = None;
2394 if let Some(trait_ref) = opt_trait_ref {
2395 let path: Vec<_> = trait_ref.path.segments.iter()
2396 .map(|seg| seg.ident)
2398 let def = self.smart_resolve_path_fragment(
2402 trait_ref.path.span,
2403 PathSource::Trait(AliasPossibility::No),
2404 CrateLint::SimplePath(trait_ref.ref_id),
2406 if def != Def::Err {
2407 new_id = Some(def.def_id());
2408 let span = trait_ref.path.span;
2409 if let PathResult::Module(module) = self.resolve_path(
2414 CrateLint::SimplePath(trait_ref.ref_id),
2416 new_val = Some((module, trait_ref.clone()));
2420 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2421 let result = f(self, new_id);
2422 self.current_trait_ref = original_trait_ref;
2426 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2427 where F: FnOnce(&mut Resolver)
2429 let mut self_type_rib = Rib::new(NormalRibKind);
2431 // plain insert (no renaming, types are not currently hygienic....)
2432 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2433 self.ribs[TypeNS].push(self_type_rib);
2435 self.ribs[TypeNS].pop();
2438 fn resolve_implementation(&mut self,
2439 generics: &Generics,
2440 opt_trait_reference: &Option<TraitRef>,
2443 impl_items: &[ImplItem]) {
2444 // If applicable, create a rib for the type parameters.
2445 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2446 // Dummy self type for better errors if `Self` is used in the trait path.
2447 this.with_self_rib(Def::SelfTy(None, None), |this| {
2448 // Resolve the trait reference, if necessary.
2449 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2450 let item_def_id = this.definitions.local_def_id(item_id);
2451 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2452 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2453 // Resolve type arguments in trait path
2454 visit::walk_trait_ref(this, trait_ref);
2456 // Resolve the self type.
2457 this.visit_ty(self_type);
2458 // Resolve the type parameters.
2459 this.visit_generics(generics);
2460 this.with_current_self_type(self_type, |this| {
2461 for impl_item in impl_items {
2462 this.check_proc_macro_attrs(&impl_item.attrs);
2463 this.resolve_visibility(&impl_item.vis);
2465 // We also need a new scope for the impl item type parameters.
2466 let type_parameters = HasTypeParameters(&impl_item.generics,
2467 TraitOrImplItemRibKind);
2468 this.with_type_parameter_rib(type_parameters, |this| {
2469 use self::ResolutionError::*;
2470 match impl_item.node {
2471 ImplItemKind::Const(..) => {
2472 // If this is a trait impl, ensure the const
2474 this.check_trait_item(impl_item.ident,
2477 |n, s| ConstNotMemberOfTrait(n, s));
2478 this.with_constant_rib(|this|
2479 visit::walk_impl_item(this, impl_item)
2482 ImplItemKind::Method(..) => {
2483 // If this is a trait impl, ensure the method
2485 this.check_trait_item(impl_item.ident,
2488 |n, s| MethodNotMemberOfTrait(n, s));
2490 visit::walk_impl_item(this, impl_item);
2492 ImplItemKind::Type(ref ty) => {
2493 // If this is a trait impl, ensure the type
2495 this.check_trait_item(impl_item.ident,
2498 |n, s| TypeNotMemberOfTrait(n, s));
2502 ImplItemKind::Existential(ref bounds) => {
2503 // If this is a trait impl, ensure the type
2505 this.check_trait_item(impl_item.ident,
2508 |n, s| TypeNotMemberOfTrait(n, s));
2510 for bound in bounds {
2511 this.visit_param_bound(bound);
2514 ImplItemKind::Macro(_) =>
2515 panic!("unexpanded macro in resolve!"),
2526 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2527 where F: FnOnce(Name, &str) -> ResolutionError
2529 // If there is a TraitRef in scope for an impl, then the method must be in the
2531 if let Some((module, _)) = self.current_trait_ref {
2532 if self.resolve_ident_in_module(module, ident, ns, false, span).is_err() {
2533 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2534 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2539 fn resolve_local(&mut self, local: &Local) {
2540 // Resolve the type.
2541 walk_list!(self, visit_ty, &local.ty);
2543 // Resolve the initializer.
2544 walk_list!(self, visit_expr, &local.init);
2546 // Resolve the pattern.
2547 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2550 // build a map from pattern identifiers to binding-info's.
2551 // this is done hygienically. This could arise for a macro
2552 // that expands into an or-pattern where one 'x' was from the
2553 // user and one 'x' came from the macro.
2554 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2555 let mut binding_map = FxHashMap();
2557 pat.walk(&mut |pat| {
2558 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2559 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2560 Some(Def::Local(..)) => true,
2563 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2564 binding_map.insert(ident, binding_info);
2573 // check that all of the arms in an or-pattern have exactly the
2574 // same set of bindings, with the same binding modes for each.
2575 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2576 if pats.is_empty() {
2580 let mut missing_vars = FxHashMap();
2581 let mut inconsistent_vars = FxHashMap();
2582 for (i, p) in pats.iter().enumerate() {
2583 let map_i = self.binding_mode_map(&p);
2585 for (j, q) in pats.iter().enumerate() {
2590 let map_j = self.binding_mode_map(&q);
2591 for (&key, &binding_i) in &map_i {
2592 if map_j.len() == 0 { // Account for missing bindings when
2593 let binding_error = missing_vars // map_j has none.
2595 .or_insert(BindingError {
2597 origin: BTreeSet::new(),
2598 target: BTreeSet::new(),
2600 binding_error.origin.insert(binding_i.span);
2601 binding_error.target.insert(q.span);
2603 for (&key_j, &binding_j) in &map_j {
2604 match map_i.get(&key_j) {
2605 None => { // missing binding
2606 let binding_error = missing_vars
2608 .or_insert(BindingError {
2610 origin: BTreeSet::new(),
2611 target: BTreeSet::new(),
2613 binding_error.origin.insert(binding_j.span);
2614 binding_error.target.insert(p.span);
2616 Some(binding_i) => { // check consistent binding
2617 if binding_i.binding_mode != binding_j.binding_mode {
2620 .or_insert((binding_j.span, binding_i.span));
2628 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2629 missing_vars.sort();
2630 for (_, v) in missing_vars {
2632 *v.origin.iter().next().unwrap(),
2633 ResolutionError::VariableNotBoundInPattern(v));
2635 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2636 inconsistent_vars.sort();
2637 for (name, v) in inconsistent_vars {
2638 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2642 fn resolve_arm(&mut self, arm: &Arm) {
2643 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2645 let mut bindings_list = FxHashMap();
2646 for pattern in &arm.pats {
2647 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2650 // This has to happen *after* we determine which pat_idents are variants
2651 self.check_consistent_bindings(&arm.pats);
2653 walk_list!(self, visit_expr, &arm.guard);
2654 self.visit_expr(&arm.body);
2656 self.ribs[ValueNS].pop();
2659 fn resolve_block(&mut self, block: &Block) {
2660 debug!("(resolving block) entering block");
2661 // Move down in the graph, if there's an anonymous module rooted here.
2662 let orig_module = self.current_module;
2663 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2665 let mut num_macro_definition_ribs = 0;
2666 if let Some(anonymous_module) = anonymous_module {
2667 debug!("(resolving block) found anonymous module, moving down");
2668 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2669 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2670 self.current_module = anonymous_module;
2671 self.finalize_current_module_macro_resolutions();
2673 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2676 // Descend into the block.
2677 for stmt in &block.stmts {
2678 if let ast::StmtKind::Item(ref item) = stmt.node {
2679 if let ast::ItemKind::MacroDef(..) = item.node {
2680 num_macro_definition_ribs += 1;
2681 let def = self.definitions.local_def_id(item.id);
2682 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2683 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2687 self.visit_stmt(stmt);
2691 self.current_module = orig_module;
2692 for _ in 0 .. num_macro_definition_ribs {
2693 self.ribs[ValueNS].pop();
2694 self.label_ribs.pop();
2696 self.ribs[ValueNS].pop();
2697 if let Some(_) = anonymous_module {
2698 self.ribs[TypeNS].pop();
2700 debug!("(resolving block) leaving block");
2703 fn fresh_binding(&mut self,
2706 outer_pat_id: NodeId,
2707 pat_src: PatternSource,
2708 bindings: &mut FxHashMap<Ident, NodeId>)
2710 // Add the binding to the local ribs, if it
2711 // doesn't already exist in the bindings map. (We
2712 // must not add it if it's in the bindings map
2713 // because that breaks the assumptions later
2714 // passes make about or-patterns.)
2715 let ident = ident.modern_and_legacy();
2716 let mut def = Def::Local(pat_id);
2717 match bindings.get(&ident).cloned() {
2718 Some(id) if id == outer_pat_id => {
2719 // `Variant(a, a)`, error
2723 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2727 Some(..) if pat_src == PatternSource::FnParam => {
2728 // `fn f(a: u8, a: u8)`, error
2732 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2736 Some(..) if pat_src == PatternSource::Match ||
2737 pat_src == PatternSource::IfLet ||
2738 pat_src == PatternSource::WhileLet => {
2739 // `Variant1(a) | Variant2(a)`, ok
2740 // Reuse definition from the first `a`.
2741 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2744 span_bug!(ident.span, "two bindings with the same name from \
2745 unexpected pattern source {:?}", pat_src);
2748 // A completely fresh binding, add to the lists if it's valid.
2749 if ident.name != keywords::Invalid.name() {
2750 bindings.insert(ident, outer_pat_id);
2751 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2756 PathResolution::new(def)
2759 fn resolve_pattern(&mut self,
2761 pat_src: PatternSource,
2762 // Maps idents to the node ID for the
2763 // outermost pattern that binds them.
2764 bindings: &mut FxHashMap<Ident, NodeId>) {
2765 // Visit all direct subpatterns of this pattern.
2766 let outer_pat_id = pat.id;
2767 pat.walk(&mut |pat| {
2769 PatKind::Ident(bmode, ident, ref opt_pat) => {
2770 // First try to resolve the identifier as some existing
2771 // entity, then fall back to a fresh binding.
2772 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2774 .and_then(LexicalScopeBinding::item);
2775 let resolution = binding.map(NameBinding::def).and_then(|def| {
2776 let is_syntactic_ambiguity = opt_pat.is_none() &&
2777 bmode == BindingMode::ByValue(Mutability::Immutable);
2779 Def::StructCtor(_, CtorKind::Const) |
2780 Def::VariantCtor(_, CtorKind::Const) |
2781 Def::Const(..) if is_syntactic_ambiguity => {
2782 // Disambiguate in favor of a unit struct/variant
2783 // or constant pattern.
2784 self.record_use(ident, ValueNS, binding.unwrap(), ident.span);
2785 Some(PathResolution::new(def))
2787 Def::StructCtor(..) | Def::VariantCtor(..) |
2788 Def::Const(..) | Def::Static(..) => {
2789 // This is unambiguously a fresh binding, either syntactically
2790 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2791 // to something unusable as a pattern (e.g. constructor function),
2792 // but we still conservatively report an error, see
2793 // issues/33118#issuecomment-233962221 for one reason why.
2797 ResolutionError::BindingShadowsSomethingUnacceptable(
2798 pat_src.descr(), ident.name, binding.unwrap())
2802 Def::Fn(..) | Def::Err => {
2803 // These entities are explicitly allowed
2804 // to be shadowed by fresh bindings.
2808 span_bug!(ident.span, "unexpected definition for an \
2809 identifier in pattern: {:?}", def);
2812 }).unwrap_or_else(|| {
2813 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2816 self.record_def(pat.id, resolution);
2819 PatKind::TupleStruct(ref path, ..) => {
2820 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2823 PatKind::Path(ref qself, ref path) => {
2824 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2827 PatKind::Struct(ref path, ..) => {
2828 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2836 visit::walk_pat(self, pat);
2839 // High-level and context dependent path resolution routine.
2840 // Resolves the path and records the resolution into definition map.
2841 // If resolution fails tries several techniques to find likely
2842 // resolution candidates, suggest imports or other help, and report
2843 // errors in user friendly way.
2844 fn smart_resolve_path(&mut self,
2846 qself: Option<&QSelf>,
2850 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2853 /// A variant of `smart_resolve_path` where you also specify extra
2854 /// information about where the path came from; this extra info is
2855 /// sometimes needed for the lint that recommends rewriting
2856 /// absolute paths to `crate`, so that it knows how to frame the
2857 /// suggestion. If you are just resolving a path like `foo::bar`
2858 /// that appears...somewhere, though, then you just want
2859 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2860 /// already provides.
2861 fn smart_resolve_path_with_crate_lint(
2864 qself: Option<&QSelf>,
2867 crate_lint: CrateLint
2868 ) -> PathResolution {
2869 let segments = &path.segments.iter()
2870 .map(|seg| seg.ident)
2871 .collect::<Vec<_>>();
2872 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2875 fn smart_resolve_path_fragment(&mut self,
2877 qself: Option<&QSelf>,
2881 crate_lint: CrateLint)
2883 let ident_span = path.last().map_or(span, |ident| ident.span);
2884 let ns = source.namespace();
2885 let is_expected = &|def| source.is_expected(def);
2886 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2888 // Base error is amended with one short label and possibly some longer helps/notes.
2889 let report_errors = |this: &mut Self, def: Option<Def>| {
2890 // Make the base error.
2891 let expected = source.descr_expected();
2892 let path_str = names_to_string(path);
2893 let code = source.error_code(def.is_some());
2894 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2895 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2896 format!("not a {}", expected),
2899 let item_str = path[path.len() - 1];
2900 let item_span = path[path.len() - 1].span;
2901 let (mod_prefix, mod_str) = if path.len() == 1 {
2902 (String::new(), "this scope".to_string())
2903 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2904 (String::new(), "the crate root".to_string())
2906 let mod_path = &path[..path.len() - 1];
2907 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS),
2908 false, span, CrateLint::No) {
2909 PathResult::Module(module) => module.def(),
2911 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
2912 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2914 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2915 format!("not found in {}", mod_str),
2918 let code = DiagnosticId::Error(code.into());
2919 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2921 // Emit special messages for unresolved `Self` and `self`.
2922 if is_self_type(path, ns) {
2923 __diagnostic_used!(E0411);
2924 err.code(DiagnosticId::Error("E0411".into()));
2925 err.span_label(span, "`Self` is only available in traits and impls");
2926 return (err, Vec::new());
2928 if is_self_value(path, ns) {
2929 __diagnostic_used!(E0424);
2930 err.code(DiagnosticId::Error("E0424".into()));
2931 err.span_label(span, format!("`self` value is only available in \
2932 methods with `self` parameter"));
2933 return (err, Vec::new());
2936 // Try to lookup the name in more relaxed fashion for better error reporting.
2937 let ident = *path.last().unwrap();
2938 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2939 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2940 let enum_candidates =
2941 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
2942 let mut enum_candidates = enum_candidates.iter()
2943 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2944 enum_candidates.sort();
2945 for (sp, variant_path, enum_path) in enum_candidates {
2947 let msg = format!("there is an enum variant `{}`, \
2953 err.span_suggestion(span, "you can try using the variant's enum",
2958 if path.len() == 1 && this.self_type_is_available(span) {
2959 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
2960 let self_is_available = this.self_value_is_available(path[0].span, span);
2962 AssocSuggestion::Field => {
2963 err.span_suggestion(span, "try",
2964 format!("self.{}", path_str));
2965 if !self_is_available {
2966 err.span_label(span, format!("`self` value is only available in \
2967 methods with `self` parameter"));
2970 AssocSuggestion::MethodWithSelf if self_is_available => {
2971 err.span_suggestion(span, "try",
2972 format!("self.{}", path_str));
2974 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2975 err.span_suggestion(span, "try",
2976 format!("Self::{}", path_str));
2979 return (err, candidates);
2983 let mut levenshtein_worked = false;
2986 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2987 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2988 levenshtein_worked = true;
2991 // Try context dependent help if relaxed lookup didn't work.
2992 if let Some(def) = def {
2993 match (def, source) {
2994 (Def::Macro(..), _) => {
2995 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2996 return (err, candidates);
2998 (Def::TyAlias(..), PathSource::Trait(_)) => {
2999 err.span_label(span, "type aliases cannot be used for traits");
3000 return (err, candidates);
3002 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3003 ExprKind::Field(_, ident) => {
3004 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3006 return (err, candidates);
3008 ExprKind::MethodCall(ref segment, ..) => {
3009 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3010 path_str, segment.ident));
3011 return (err, candidates);
3015 (Def::Enum(..), PathSource::TupleStruct)
3016 | (Def::Enum(..), PathSource::Expr(..)) => {
3017 if let Some(variants) = this.collect_enum_variants(def) {
3018 err.note(&format!("did you mean to use one \
3019 of the following variants?\n{}",
3021 .map(|suggestion| path_names_to_string(suggestion))
3022 .map(|suggestion| format!("- `{}`", suggestion))
3023 .collect::<Vec<_>>()
3027 err.note("did you mean to use one of the enum's variants?");
3029 return (err, candidates);
3031 (Def::Struct(def_id), _) if ns == ValueNS => {
3032 if let Some((ctor_def, ctor_vis))
3033 = this.struct_constructors.get(&def_id).cloned() {
3034 let accessible_ctor = this.is_accessible(ctor_vis);
3035 if is_expected(ctor_def) && !accessible_ctor {
3036 err.span_label(span, format!("constructor is not visible \
3037 here due to private fields"));
3040 // HACK(estebank): find a better way to figure out that this was a
3041 // parser issue where a struct literal is being used on an expression
3042 // where a brace being opened means a block is being started. Look
3043 // ahead for the next text to see if `span` is followed by a `{`.
3044 let cm = this.session.codemap();
3047 sp = cm.next_point(sp);
3048 match cm.span_to_snippet(sp) {
3049 Ok(ref snippet) => {
3050 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3057 let followed_by_brace = match cm.span_to_snippet(sp) {
3058 Ok(ref snippet) if snippet == "{" => true,
3061 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3064 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3069 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3073 return (err, candidates);
3075 (Def::Union(..), _) |
3076 (Def::Variant(..), _) |
3077 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3078 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3080 return (err, candidates);
3082 (Def::SelfTy(..), _) if ns == ValueNS => {
3083 err.span_label(span, fallback_label);
3084 err.note("can't use `Self` as a constructor, you must use the \
3085 implemented struct");
3086 return (err, candidates);
3088 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3089 err.note("can't use a type alias as a constructor");
3090 return (err, candidates);
3097 if !levenshtein_worked {
3098 err.span_label(base_span, fallback_label);
3099 this.type_ascription_suggestion(&mut err, base_span);
3103 let report_errors = |this: &mut Self, def: Option<Def>| {
3104 let (err, candidates) = report_errors(this, def);
3105 let def_id = this.current_module.normal_ancestor_id;
3106 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3107 let better = def.is_some();
3108 this.use_injections.push(UseError { err, candidates, node_id, better });
3109 err_path_resolution()
3112 let resolution = match self.resolve_qpath_anywhere(
3118 source.defer_to_typeck(),
3119 source.global_by_default(),
3122 Some(resolution) if resolution.unresolved_segments() == 0 => {
3123 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3126 // Add a temporary hack to smooth the transition to new struct ctor
3127 // visibility rules. See #38932 for more details.
3129 if let Def::Struct(def_id) = resolution.base_def() {
3130 if let Some((ctor_def, ctor_vis))
3131 = self.struct_constructors.get(&def_id).cloned() {
3132 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3133 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3134 self.session.buffer_lint(lint, id, span,
3135 "private struct constructors are not usable through \
3136 re-exports in outer modules",
3138 res = Some(PathResolution::new(ctor_def));
3143 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3146 Some(resolution) if source.defer_to_typeck() => {
3147 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3148 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3149 // it needs to be added to the trait map.
3151 let item_name = *path.last().unwrap();
3152 let traits = self.get_traits_containing_item(item_name, ns);
3153 self.trait_map.insert(id, traits);
3157 _ => report_errors(self, None)
3160 if let PathSource::TraitItem(..) = source {} else {
3161 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3162 self.record_def(id, resolution);
3167 fn type_ascription_suggestion(&self,
3168 err: &mut DiagnosticBuilder,
3170 debug!("type_ascription_suggetion {:?}", base_span);
3171 let cm = self.session.codemap();
3172 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3173 if let Some(sp) = self.current_type_ascription.last() {
3175 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3176 sp = cm.next_point(sp);
3177 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3178 debug!("snippet {:?}", snippet);
3179 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3180 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3181 debug!("{:?} {:?}", line_sp, line_base_sp);
3183 err.span_label(base_span,
3184 "expecting a type here because of type ascription");
3185 if line_sp != line_base_sp {
3186 err.span_suggestion_short(sp,
3187 "did you mean to use `;` here instead?",
3191 } else if snippet.trim().len() != 0 {
3192 debug!("tried to find type ascription `:` token, couldn't find it");
3202 fn self_type_is_available(&mut self, span: Span) -> bool {
3203 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3204 TypeNS, None, span);
3205 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3208 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3209 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3210 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3211 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3214 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3215 fn resolve_qpath_anywhere(&mut self,
3217 qself: Option<&QSelf>,
3219 primary_ns: Namespace,
3221 defer_to_typeck: bool,
3222 global_by_default: bool,
3223 crate_lint: CrateLint)
3224 -> Option<PathResolution> {
3225 let mut fin_res = None;
3226 // FIXME: can't resolve paths in macro namespace yet, macros are
3227 // processed by the little special hack below.
3228 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3229 if i == 0 || ns != primary_ns {
3230 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3231 // If defer_to_typeck, then resolution > no resolution,
3232 // otherwise full resolution > partial resolution > no resolution.
3233 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3235 res => if fin_res.is_none() { fin_res = res },
3239 let is_global = self.macro_prelude.get(&path[0].name).cloned()
3240 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3241 if primary_ns != MacroNS && (is_global ||
3242 self.macro_names.contains(&path[0].modern())) {
3243 // Return some dummy definition, it's enough for error reporting.
3245 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3251 /// Handles paths that may refer to associated items.
3252 fn resolve_qpath(&mut self,
3254 qself: Option<&QSelf>,
3258 global_by_default: bool,
3259 crate_lint: CrateLint)
3260 -> Option<PathResolution> {
3262 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3263 ns={:?}, span={:?}, global_by_default={:?})",
3272 if let Some(qself) = qself {
3273 if qself.position == 0 {
3274 // This is a case like `<T>::B`, where there is no
3275 // trait to resolve. In that case, we leave the `B`
3276 // segment to be resolved by type-check.
3277 return Some(PathResolution::with_unresolved_segments(
3278 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3282 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3284 // Currently, `path` names the full item (`A::B::C`, in
3285 // our example). so we extract the prefix of that that is
3286 // the trait (the slice upto and including
3287 // `qself.position`). And then we recursively resolve that,
3288 // but with `qself` set to `None`.
3290 // However, setting `qself` to none (but not changing the
3291 // span) loses the information about where this path
3292 // *actually* appears, so for the purposes of the crate
3293 // lint we pass along information that this is the trait
3294 // name from a fully qualified path, and this also
3295 // contains the full span (the `CrateLint::QPathTrait`).
3296 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3297 let res = self.smart_resolve_path_fragment(
3300 &path[..qself.position + 1],
3302 PathSource::TraitItem(ns),
3303 CrateLint::QPathTrait {
3305 qpath_span: qself.path_span,
3309 // The remaining segments (the `C` in our example) will
3310 // have to be resolved by type-check, since that requires doing
3311 // trait resolution.
3312 return Some(PathResolution::with_unresolved_segments(
3313 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3317 let result = match self.resolve_path(
3324 PathResult::NonModule(path_res) => path_res,
3325 PathResult::Module(module) if !module.is_normal() => {
3326 PathResolution::new(module.def().unwrap())
3328 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3329 // don't report an error right away, but try to fallback to a primitive type.
3330 // So, we are still able to successfully resolve something like
3332 // use std::u8; // bring module u8 in scope
3333 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3334 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3335 // // not to non-existent std::u8::max_value
3338 // Such behavior is required for backward compatibility.
3339 // The same fallback is used when `a` resolves to nothing.
3340 PathResult::Module(..) | PathResult::Failed(..)
3341 if (ns == TypeNS || path.len() > 1) &&
3342 self.primitive_type_table.primitive_types
3343 .contains_key(&path[0].name) => {
3344 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3345 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3347 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
3348 PathResult::Failed(span, msg, false) => {
3349 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3350 err_path_resolution()
3352 PathResult::Failed(..) => return None,
3353 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3356 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3357 path[0].name != keywords::CrateRoot.name() &&
3358 path[0].name != keywords::DollarCrate.name() {
3359 let unqualified_result = {
3360 match self.resolve_path(
3361 &[*path.last().unwrap()],
3367 PathResult::NonModule(path_res) => path_res.base_def(),
3368 PathResult::Module(module) => module.def().unwrap(),
3369 _ => return Some(result),
3372 if result.base_def() == unqualified_result {
3373 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3374 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3384 opt_ns: Option<Namespace>, // `None` indicates a module path
3387 crate_lint: CrateLint,
3388 ) -> PathResult<'a> {
3389 let mut module = None;
3390 let mut allow_super = true;
3391 let mut second_binding = None;
3394 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3395 path_span={:?}, crate_lint={:?})",
3403 for (i, &ident) in path.iter().enumerate() {
3404 debug!("resolve_path ident {} {:?}", i, ident);
3405 let is_last = i == path.len() - 1;
3406 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3407 let name = ident.name;
3409 if i == 0 && ns == TypeNS && name == keywords::SelfValue.name() {
3410 let mut ctxt = ident.span.ctxt().modern();
3411 module = Some(self.resolve_self(&mut ctxt, self.current_module));
3413 } else if allow_super && ns == TypeNS && name == keywords::Super.name() {
3414 let mut ctxt = ident.span.ctxt().modern();
3415 let self_module = match i {
3416 0 => self.resolve_self(&mut ctxt, self.current_module),
3417 _ => module.unwrap(),
3419 if let Some(parent) = self_module.parent {
3420 module = Some(self.resolve_self(&mut ctxt, parent));
3423 let msg = "There are too many initial `super`s.".to_string();
3424 return PathResult::Failed(ident.span, msg, false);
3426 } else if i == 0 && ns == TypeNS && name == keywords::Extern.name() {
3429 allow_super = false;
3432 if (i == 0 && name == keywords::CrateRoot.name()) ||
3433 (i == 0 && name == keywords::Crate.name()) ||
3434 (i == 0 && name == keywords::DollarCrate.name()) ||
3435 (i == 1 && name == keywords::Crate.name() &&
3436 path[0].name == keywords::CrateRoot.name()) {
3437 // `::a::b`, `crate::a::b`, `::crate::a::b` or `$crate::a::b`
3438 module = Some(self.resolve_crate_root(ident));
3440 } else if i == 1 && !ident.is_path_segment_keyword() {
3441 let prev_name = path[0].name;
3442 if prev_name == keywords::Extern.name() ||
3443 prev_name == keywords::CrateRoot.name() &&
3444 self.session.features_untracked().extern_absolute_paths &&
3445 self.session.rust_2018() {
3446 // `::extern_crate::a::b`
3447 let crate_id = self.crate_loader.process_path_extern(name, ident.span);
3449 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3450 self.populate_module_if_necessary(crate_root);
3451 module = Some(crate_root);
3457 // Report special messages for path segment keywords in wrong positions.
3458 if name == keywords::CrateRoot.name() && i != 0 ||
3459 name == keywords::DollarCrate.name() && i != 0 ||
3460 name == keywords::SelfValue.name() && i != 0 ||
3461 name == keywords::SelfType.name() && i != 0 ||
3462 name == keywords::Super.name() && i != 0 ||
3463 name == keywords::Extern.name() && i != 0 ||
3464 // we allow crate::foo and ::crate::foo but nothing else
3465 name == keywords::Crate.name() && i > 1 &&
3466 path[0].name != keywords::CrateRoot.name() ||
3467 name == keywords::Crate.name() && path.len() == 1 {
3468 let name_str = if name == keywords::CrateRoot.name() {
3469 "crate root".to_string()
3471 format!("`{}`", name)
3473 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3474 format!("global paths cannot start with {}", name_str)
3476 format!("{} in paths can only be used in start position", name_str)
3478 return PathResult::Failed(ident.span, msg, false);
3481 let binding = if let Some(module) = module {
3482 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3483 } else if opt_ns == Some(MacroNS) {
3484 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
3485 .map(MacroBinding::binding)
3487 let record_used_id =
3488 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3489 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3490 // we found a locally-imported or available item/module
3491 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3492 // we found a local variable or type param
3493 Some(LexicalScopeBinding::Def(def))
3494 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3495 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3499 _ => Err(if record_used { Determined } else { Undetermined }),
3506 second_binding = Some(binding);
3508 let def = binding.def();
3509 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3510 if let Some(next_module) = binding.module() {
3511 module = Some(next_module);
3512 } else if def == Def::ToolMod && i + 1 != path.len() {
3513 return PathResult::NonModule(PathResolution::new(Def::NonMacroAttr))
3514 } else if def == Def::Err {
3515 return PathResult::NonModule(err_path_resolution());
3516 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3517 self.lint_if_path_starts_with_module(
3523 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3524 def, path.len() - i - 1
3527 return PathResult::Failed(ident.span,
3528 format!("Not a module `{}`", ident),
3532 Err(Undetermined) => return PathResult::Indeterminate,
3533 Err(Determined) => {
3534 if let Some(module) = module {
3535 if opt_ns.is_some() && !module.is_normal() {
3536 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3537 module.def().unwrap(), path.len() - i
3541 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
3542 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3543 let mut candidates =
3544 self.lookup_import_candidates(name, TypeNS, is_mod);
3545 candidates.sort_by_cached_key(|c| {
3546 (c.path.segments.len(), c.path.to_string())
3548 if let Some(candidate) = candidates.get(0) {
3549 format!("Did you mean `{}`?", candidate.path)
3551 format!("Maybe a missing `extern crate {};`?", ident)
3554 format!("Use of undeclared type or module `{}`", ident)
3556 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3558 return PathResult::Failed(ident.span, msg, is_last);
3563 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3565 PathResult::Module(module.unwrap_or(self.graph_root))
3568 fn lint_if_path_starts_with_module(
3570 crate_lint: CrateLint,
3573 second_binding: Option<&NameBinding>,
3575 let (diag_id, diag_span) = match crate_lint {
3576 CrateLint::No => return,
3577 CrateLint::SimplePath(id) => (id, path_span),
3578 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3579 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3582 let first_name = match path.get(0) {
3583 Some(ident) => ident.name,
3587 // We're only interested in `use` paths which should start with
3588 // `{{root}}` or `extern` currently.
3589 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3594 // If this import looks like `crate::...` it's already good
3595 Some(ident) if ident.name == keywords::Crate.name() => return,
3596 // Otherwise go below to see if it's an extern crate
3598 // If the path has length one (and it's `CrateRoot` most likely)
3599 // then we don't know whether we're gonna be importing a crate or an
3600 // item in our crate. Defer this lint to elsewhere
3604 // If the first element of our path was actually resolved to an
3605 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3606 // warning, this looks all good!
3607 if let Some(binding) = second_binding {
3608 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3609 // Careful: we still want to rewrite paths from
3610 // renamed extern crates.
3611 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3617 self.lint_path_starts_with_module(diag_id, diag_span);
3620 fn lint_path_starts_with_module(&self, id: NodeId, span: Span) {
3621 // In the 2018 edition this lint is a hard error, so nothing to do
3622 if self.session.rust_2018() {
3625 // In the 2015 edition there's no use in emitting lints unless the
3626 // crate's already enabled the feature that we're going to suggest
3627 if !self.session.features_untracked().crate_in_paths {
3630 let diag = lint::builtin::BuiltinLintDiagnostics
3631 ::AbsPathWithModule(span);
3632 self.session.buffer_lint_with_diagnostic(
3633 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3635 "absolute paths must start with `self`, `super`, \
3636 `crate`, or an external crate name in the 2018 edition",
3640 // Resolve a local definition, potentially adjusting for closures.
3641 fn adjust_local_def(&mut self,
3646 span: Span) -> Def {
3647 let ribs = &self.ribs[ns][rib_index + 1..];
3649 // An invalid forward use of a type parameter from a previous default.
3650 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3652 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3654 assert_eq!(def, Def::Err);
3660 span_bug!(span, "unexpected {:?} in bindings", def)
3662 Def::Local(node_id) => {
3665 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3666 ForwardTyParamBanRibKind => {
3667 // Nothing to do. Continue.
3669 ClosureRibKind(function_id) => {
3672 let seen = self.freevars_seen
3674 .or_insert_with(|| NodeMap());
3675 if let Some(&index) = seen.get(&node_id) {
3676 def = Def::Upvar(node_id, index, function_id);
3679 let vec = self.freevars
3681 .or_insert_with(|| vec![]);
3682 let depth = vec.len();
3683 def = Def::Upvar(node_id, depth, function_id);
3690 seen.insert(node_id, depth);
3693 ItemRibKind | TraitOrImplItemRibKind => {
3694 // This was an attempt to access an upvar inside a
3695 // named function item. This is not allowed, so we
3698 resolve_error(self, span,
3699 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3703 ConstantItemRibKind => {
3704 // Still doesn't deal with upvars
3706 resolve_error(self, span,
3707 ResolutionError::AttemptToUseNonConstantValueInConstant);
3714 Def::TyParam(..) | Def::SelfTy(..) => {
3717 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3718 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3719 ConstantItemRibKind => {
3720 // Nothing to do. Continue.
3723 // This was an attempt to use a type parameter outside
3726 resolve_error(self, span,
3727 ResolutionError::TypeParametersFromOuterFunction(def));
3739 fn lookup_assoc_candidate<FilterFn>(&mut self,
3742 filter_fn: FilterFn)
3743 -> Option<AssocSuggestion>
3744 where FilterFn: Fn(Def) -> bool
3746 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3748 TyKind::Path(None, _) => Some(t.id),
3749 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3750 // This doesn't handle the remaining `Ty` variants as they are not
3751 // that commonly the self_type, it might be interesting to provide
3752 // support for those in future.
3757 // Fields are generally expected in the same contexts as locals.
3758 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3759 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3760 // Look for a field with the same name in the current self_type.
3761 if let Some(resolution) = self.def_map.get(&node_id) {
3762 match resolution.base_def() {
3763 Def::Struct(did) | Def::Union(did)
3764 if resolution.unresolved_segments() == 0 => {
3765 if let Some(field_names) = self.field_names.get(&did) {
3766 if field_names.iter().any(|&field_name| ident.name == field_name) {
3767 return Some(AssocSuggestion::Field);
3777 // Look for associated items in the current trait.
3778 if let Some((module, _)) = self.current_trait_ref {
3779 if let Ok(binding) =
3780 self.resolve_ident_in_module(module, ident, ns, false, module.span) {
3781 let def = binding.def();
3783 return Some(if self.has_self.contains(&def.def_id()) {
3784 AssocSuggestion::MethodWithSelf
3786 AssocSuggestion::AssocItem
3795 fn lookup_typo_candidate<FilterFn>(&mut self,
3798 filter_fn: FilterFn,
3801 where FilterFn: Fn(Def) -> bool
3803 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3804 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3805 if let Some(binding) = resolution.borrow().binding {
3806 if filter_fn(binding.def()) {
3807 names.push(ident.name);
3813 let mut names = Vec::new();
3814 if path.len() == 1 {
3815 // Search in lexical scope.
3816 // Walk backwards up the ribs in scope and collect candidates.
3817 for rib in self.ribs[ns].iter().rev() {
3818 // Locals and type parameters
3819 for (ident, def) in &rib.bindings {
3820 if filter_fn(*def) {
3821 names.push(ident.name);
3825 if let ModuleRibKind(module) = rib.kind {
3826 // Items from this module
3827 add_module_candidates(module, &mut names);
3829 if let ModuleKind::Block(..) = module.kind {
3830 // We can see through blocks
3832 // Items from the prelude
3833 if !module.no_implicit_prelude {
3834 names.extend(self.extern_prelude.iter().cloned());
3835 if let Some(prelude) = self.prelude {
3836 add_module_candidates(prelude, &mut names);
3843 // Add primitive types to the mix
3844 if filter_fn(Def::PrimTy(TyBool)) {
3846 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3850 // Search in module.
3851 let mod_path = &path[..path.len() - 1];
3852 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3853 false, span, CrateLint::No) {
3854 add_module_candidates(module, &mut names);
3858 let name = path[path.len() - 1].name;
3859 // Make sure error reporting is deterministic.
3860 names.sort_by_cached_key(|name| name.as_str());
3861 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3862 Some(found) if found != name => Some(found),
3867 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3868 where F: FnOnce(&mut Resolver)
3870 if let Some(label) = label {
3871 self.unused_labels.insert(id, label.ident.span);
3872 let def = Def::Label(id);
3873 self.with_label_rib(|this| {
3874 let ident = label.ident.modern_and_legacy();
3875 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
3883 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3884 self.with_resolved_label(label, id, |this| this.visit_block(block));
3887 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3888 // First, record candidate traits for this expression if it could
3889 // result in the invocation of a method call.
3891 self.record_candidate_traits_for_expr_if_necessary(expr);
3893 // Next, resolve the node.
3895 ExprKind::Path(ref qself, ref path) => {
3896 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3897 visit::walk_expr(self, expr);
3900 ExprKind::Struct(ref path, ..) => {
3901 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3902 visit::walk_expr(self, expr);
3905 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3906 let def = self.search_label(label.ident, |rib, ident| {
3907 rib.bindings.get(&ident.modern_and_legacy()).cloned()
3911 // Search again for close matches...
3912 // Picks the first label that is "close enough", which is not necessarily
3913 // the closest match
3914 let close_match = self.search_label(label.ident, |rib, ident| {
3915 let names = rib.bindings.iter().map(|(id, _)| &id.name);
3916 find_best_match_for_name(names, &*ident.as_str(), None)
3918 self.record_def(expr.id, err_path_resolution());
3921 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
3924 Some(Def::Label(id)) => {
3925 // Since this def is a label, it is never read.
3926 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
3927 self.unused_labels.remove(&id);
3930 span_bug!(expr.span, "label wasn't mapped to a label def!");
3934 // visit `break` argument if any
3935 visit::walk_expr(self, expr);
3938 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
3939 self.visit_expr(subexpression);
3941 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3942 let mut bindings_list = FxHashMap();
3944 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
3946 // This has to happen *after* we determine which pat_idents are variants
3947 self.check_consistent_bindings(pats);
3948 self.visit_block(if_block);
3949 self.ribs[ValueNS].pop();
3951 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3954 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3956 ExprKind::While(ref subexpression, ref block, label) => {
3957 self.with_resolved_label(label, expr.id, |this| {
3958 this.visit_expr(subexpression);
3959 this.visit_block(block);
3963 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
3964 self.with_resolved_label(label, expr.id, |this| {
3965 this.visit_expr(subexpression);
3966 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3967 let mut bindings_list = FxHashMap();
3969 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
3971 // This has to happen *after* we determine which pat_idents are variants
3972 this.check_consistent_bindings(pats);
3973 this.visit_block(block);
3974 this.ribs[ValueNS].pop();
3978 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3979 self.visit_expr(subexpression);
3980 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3981 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3983 self.resolve_labeled_block(label, expr.id, block);
3985 self.ribs[ValueNS].pop();
3988 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
3990 // Equivalent to `visit::walk_expr` + passing some context to children.
3991 ExprKind::Field(ref subexpression, _) => {
3992 self.resolve_expr(subexpression, Some(expr));
3994 ExprKind::MethodCall(ref segment, ref arguments) => {
3995 let mut arguments = arguments.iter();
3996 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3997 for argument in arguments {
3998 self.resolve_expr(argument, None);
4000 self.visit_path_segment(expr.span, segment);
4003 ExprKind::Call(ref callee, ref arguments) => {
4004 self.resolve_expr(callee, Some(expr));
4005 for argument in arguments {
4006 self.resolve_expr(argument, None);
4009 ExprKind::Type(ref type_expr, _) => {
4010 self.current_type_ascription.push(type_expr.span);
4011 visit::walk_expr(self, expr);
4012 self.current_type_ascription.pop();
4014 // Resolve the body of async exprs inside the async closure to which they desugar
4015 ExprKind::Async(_, async_closure_id, ref block) => {
4016 let rib_kind = ClosureRibKind(async_closure_id);
4017 self.ribs[ValueNS].push(Rib::new(rib_kind));
4018 self.label_ribs.push(Rib::new(rib_kind));
4019 self.visit_block(&block);
4020 self.label_ribs.pop();
4021 self.ribs[ValueNS].pop();
4023 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4024 // resolve the arguments within the proper scopes so that usages of them inside the
4025 // closure are detected as upvars rather than normal closure arg usages.
4027 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4028 ref fn_decl, ref body, _span,
4030 let rib_kind = ClosureRibKind(expr.id);
4031 self.ribs[ValueNS].push(Rib::new(rib_kind));
4032 self.label_ribs.push(Rib::new(rib_kind));
4033 // Resolve arguments:
4034 let mut bindings_list = FxHashMap();
4035 for argument in &fn_decl.inputs {
4036 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4037 self.visit_ty(&argument.ty);
4039 // No need to resolve return type-- the outer closure return type is
4040 // FunctionRetTy::Default
4042 // Now resolve the inner closure
4044 let rib_kind = ClosureRibKind(inner_closure_id);
4045 self.ribs[ValueNS].push(Rib::new(rib_kind));
4046 self.label_ribs.push(Rib::new(rib_kind));
4047 // No need to resolve arguments: the inner closure has none.
4048 // Resolve the return type:
4049 visit::walk_fn_ret_ty(self, &fn_decl.output);
4051 self.visit_expr(body);
4052 self.label_ribs.pop();
4053 self.ribs[ValueNS].pop();
4055 self.label_ribs.pop();
4056 self.ribs[ValueNS].pop();
4059 visit::walk_expr(self, expr);
4064 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4066 ExprKind::Field(_, ident) => {
4067 // FIXME(#6890): Even though you can't treat a method like a
4068 // field, we need to add any trait methods we find that match
4069 // the field name so that we can do some nice error reporting
4070 // later on in typeck.
4071 let traits = self.get_traits_containing_item(ident, ValueNS);
4072 self.trait_map.insert(expr.id, traits);
4074 ExprKind::MethodCall(ref segment, ..) => {
4075 debug!("(recording candidate traits for expr) recording traits for {}",
4077 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4078 self.trait_map.insert(expr.id, traits);
4086 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4087 -> Vec<TraitCandidate> {
4088 debug!("(getting traits containing item) looking for '{}'", ident.name);
4090 let mut found_traits = Vec::new();
4091 // Look for the current trait.
4092 if let Some((module, _)) = self.current_trait_ref {
4093 if self.resolve_ident_in_module(module, ident, ns, false, module.span).is_ok() {
4094 let def_id = module.def_id().unwrap();
4095 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4099 ident.span = ident.span.modern();
4100 let mut search_module = self.current_module;
4102 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4103 search_module = unwrap_or!(
4104 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4108 if let Some(prelude) = self.prelude {
4109 if !search_module.no_implicit_prelude {
4110 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4117 fn get_traits_in_module_containing_item(&mut self,
4121 found_traits: &mut Vec<TraitCandidate>) {
4122 let mut traits = module.traits.borrow_mut();
4123 if traits.is_none() {
4124 let mut collected_traits = Vec::new();
4125 module.for_each_child(|name, ns, binding| {
4126 if ns != TypeNS { return }
4127 if let Def::Trait(_) = binding.def() {
4128 collected_traits.push((name, binding));
4131 *traits = Some(collected_traits.into_boxed_slice());
4134 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4135 let module = binding.module().unwrap();
4136 let mut ident = ident;
4137 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4140 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
4142 let import_id = match binding.kind {
4143 NameBindingKind::Import { directive, .. } => {
4144 self.maybe_unused_trait_imports.insert(directive.id);
4145 self.add_to_glob_map(directive.id, trait_name);
4150 let trait_def_id = module.def_id().unwrap();
4151 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4156 /// When name resolution fails, this method can be used to look up candidate
4157 /// entities with the expected name. It allows filtering them using the
4158 /// supplied predicate (which should be used to only accept the types of
4159 /// definitions expected e.g. traits). The lookup spans across all crates.
4161 /// NOTE: The method does not look into imports, but this is not a problem,
4162 /// since we report the definitions (thus, the de-aliased imports).
4163 fn lookup_import_candidates<FilterFn>(&mut self,
4165 namespace: Namespace,
4166 filter_fn: FilterFn)
4167 -> Vec<ImportSuggestion>
4168 where FilterFn: Fn(Def) -> bool
4170 let mut candidates = Vec::new();
4171 let mut worklist = Vec::new();
4172 let mut seen_modules = FxHashSet();
4173 worklist.push((self.graph_root, Vec::new(), false));
4175 while let Some((in_module,
4177 in_module_is_extern)) = worklist.pop() {
4178 self.populate_module_if_necessary(in_module);
4180 // We have to visit module children in deterministic order to avoid
4181 // instabilities in reported imports (#43552).
4182 in_module.for_each_child_stable(|ident, ns, name_binding| {
4183 // avoid imports entirely
4184 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4185 // avoid non-importable candidates as well
4186 if !name_binding.is_importable() { return; }
4188 // collect results based on the filter function
4189 if ident.name == lookup_name && ns == namespace {
4190 if filter_fn(name_binding.def()) {
4192 let mut segms = if self.session.rust_2018() && !in_module_is_extern {
4193 // crate-local absolute paths start with `crate::` in edition 2018
4194 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4195 let mut full_segms = vec![
4196 ast::PathSegment::from_ident(keywords::Crate.ident())
4198 full_segms.extend(path_segments.clone());
4201 path_segments.clone()
4204 segms.push(ast::PathSegment::from_ident(ident));
4206 span: name_binding.span,
4209 // the entity is accessible in the following cases:
4210 // 1. if it's defined in the same crate, it's always
4211 // accessible (since private entities can be made public)
4212 // 2. if it's defined in another crate, it's accessible
4213 // only if both the module is public and the entity is
4214 // declared as public (due to pruning, we don't explore
4215 // outside crate private modules => no need to check this)
4216 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4217 candidates.push(ImportSuggestion { path: path });
4222 // collect submodules to explore
4223 if let Some(module) = name_binding.module() {
4225 let mut path_segments = path_segments.clone();
4226 path_segments.push(ast::PathSegment::from_ident(ident));
4228 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4229 // add the module to the lookup
4230 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4231 if seen_modules.insert(module.def_id().unwrap()) {
4232 worklist.push((module, path_segments, is_extern));
4242 fn find_module(&mut self,
4244 -> Option<(Module<'a>, ImportSuggestion)>
4246 let mut result = None;
4247 let mut worklist = Vec::new();
4248 let mut seen_modules = FxHashSet();
4249 worklist.push((self.graph_root, Vec::new()));
4251 while let Some((in_module, path_segments)) = worklist.pop() {
4252 // abort if the module is already found
4253 if let Some(_) = result { break; }
4255 self.populate_module_if_necessary(in_module);
4257 in_module.for_each_child_stable(|ident, _, name_binding| {
4258 // abort if the module is already found or if name_binding is private external
4259 if result.is_some() || !name_binding.vis.is_visible_locally() {
4262 if let Some(module) = name_binding.module() {
4264 let mut path_segments = path_segments.clone();
4265 path_segments.push(ast::PathSegment::from_ident(ident));
4266 if module.def() == Some(module_def) {
4268 span: name_binding.span,
4269 segments: path_segments,
4271 result = Some((module, ImportSuggestion { path: path }));
4273 // add the module to the lookup
4274 if seen_modules.insert(module.def_id().unwrap()) {
4275 worklist.push((module, path_segments));
4285 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4286 if let Def::Enum(..) = enum_def {} else {
4287 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4290 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4291 self.populate_module_if_necessary(enum_module);
4293 let mut variants = Vec::new();
4294 enum_module.for_each_child_stable(|ident, _, name_binding| {
4295 if let Def::Variant(..) = name_binding.def() {
4296 let mut segms = enum_import_suggestion.path.segments.clone();
4297 segms.push(ast::PathSegment::from_ident(ident));
4298 variants.push(Path {
4299 span: name_binding.span,
4308 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4309 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4310 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4311 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4315 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4317 ast::VisibilityKind::Public => ty::Visibility::Public,
4318 ast::VisibilityKind::Crate(..) => {
4319 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4321 ast::VisibilityKind::Inherited => {
4322 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4324 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4325 // Visibilities are resolved as global by default, add starting root segment.
4326 let segments = path.make_root().iter().chain(path.segments.iter())
4327 .map(|seg| seg.ident)
4328 .collect::<Vec<_>>();
4329 let def = self.smart_resolve_path_fragment(
4334 PathSource::Visibility,
4335 CrateLint::SimplePath(id),
4337 if def == Def::Err {
4338 ty::Visibility::Public
4340 let vis = ty::Visibility::Restricted(def.def_id());
4341 if self.is_accessible(vis) {
4344 self.session.span_err(path.span, "visibilities can only be restricted \
4345 to ancestor modules");
4346 ty::Visibility::Public
4353 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4354 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4357 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4358 vis.is_accessible_from(module.normal_ancestor_id, self)
4361 fn report_errors(&mut self, krate: &Crate) {
4362 self.report_shadowing_errors();
4363 self.report_with_use_injections(krate);
4364 self.report_proc_macro_import(krate);
4365 let mut reported_spans = FxHashSet();
4367 for &AmbiguityError { span, name, b1, b2, lexical } in &self.ambiguity_errors {
4368 if !reported_spans.insert(span) { continue }
4369 let participle = |binding: &NameBinding| {
4370 if binding.is_import() { "imported" } else { "defined" }
4372 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
4373 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
4374 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
4375 format!("consider adding an explicit import of `{}` to disambiguate", name)
4376 } else if let Def::Macro(..) = b1.def() {
4377 format!("macro-expanded {} do not shadow",
4378 if b1.is_import() { "macro imports" } else { "macros" })
4380 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4381 if b1.is_import() { "imports" } else { "items" })
4384 let mut err = struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
4385 err.span_note(b1.span, &msg1);
4387 Def::Macro(..) if b2.span.is_dummy() =>
4388 err.note(&format!("`{}` is also a builtin macro", name)),
4389 _ => err.span_note(b2.span, &msg2),
4391 err.note(¬e).emit();
4394 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4395 if !reported_spans.insert(span) { continue }
4396 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4400 fn report_with_use_injections(&mut self, krate: &Crate) {
4401 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4402 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4403 if !candidates.is_empty() {
4404 show_candidates(&mut err, span, &candidates, better, found_use);
4410 fn report_shadowing_errors(&mut self) {
4411 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
4412 self.resolve_legacy_scope(scope, ident, true);
4415 let mut reported_errors = FxHashSet();
4416 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4417 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4418 reported_errors.insert((binding.ident, binding.span)) {
4419 let msg = format!("`{}` is already in scope", binding.ident);
4420 self.session.struct_span_err(binding.span, &msg)
4421 .note("macro-expanded `macro_rules!`s may not shadow \
4422 existing macros (see RFC 1560)")
4428 fn report_conflict<'b>(&mut self,
4432 new_binding: &NameBinding<'b>,
4433 old_binding: &NameBinding<'b>) {
4434 // Error on the second of two conflicting names
4435 if old_binding.span.lo() > new_binding.span.lo() {
4436 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4439 let container = match parent.kind {
4440 ModuleKind::Def(Def::Mod(_), _) => "module",
4441 ModuleKind::Def(Def::Trait(_), _) => "trait",
4442 ModuleKind::Block(..) => "block",
4446 let old_noun = match old_binding.is_import() {
4448 false => "definition",
4451 let new_participle = match new_binding.is_import() {
4456 let (name, span) = (ident.name, self.session.codemap().def_span(new_binding.span));
4458 if let Some(s) = self.name_already_seen.get(&name) {
4464 let old_kind = match (ns, old_binding.module()) {
4465 (ValueNS, _) => "value",
4466 (MacroNS, _) => "macro",
4467 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4468 (TypeNS, Some(module)) if module.is_normal() => "module",
4469 (TypeNS, Some(module)) if module.is_trait() => "trait",
4470 (TypeNS, _) => "type",
4473 let msg = format!("the name `{}` is defined multiple times", name);
4475 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4476 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4477 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4478 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4479 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4481 _ => match (old_binding.is_import(), new_binding.is_import()) {
4482 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4483 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4484 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4488 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4493 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4494 if !old_binding.span.is_dummy() {
4495 err.span_label(self.session.codemap().def_span(old_binding.span),
4496 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4499 // See https://github.com/rust-lang/rust/issues/32354
4500 if old_binding.is_import() || new_binding.is_import() {
4501 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4507 let cm = self.session.codemap();
4508 let rename_msg = "You can use `as` to change the binding name of the import";
4510 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4511 binding.is_renamed_extern_crate()) {
4512 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4513 format!("Other{}", name)
4515 format!("other_{}", name)
4518 err.span_suggestion(binding.span,
4520 if snippet.ends_with(';') {
4521 format!("{} as {};",
4522 &snippet[..snippet.len()-1],
4525 format!("{} as {}", snippet, suggested_name)
4528 err.span_label(binding.span, rename_msg);
4533 self.name_already_seen.insert(name, span);
4536 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
4537 if self.use_extern_macros { return; }
4540 if attr.path.segments.len() > 1 {
4543 let ident = attr.path.segments[0].ident;
4544 let result = self.resolve_lexical_macro_path_segment(ident,
4548 if let Ok(binding) = result {
4549 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
4550 attr::mark_known(attr);
4552 let msg = "attribute procedural macros are experimental";
4553 let feature = "use_extern_macros";
4555 feature_err(&self.session.parse_sess, feature,
4556 attr.span, GateIssue::Language, msg)
4557 .span_label(binding.span(), "procedural macro imported here")
4565 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4566 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4569 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4570 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4573 fn names_to_string(idents: &[Ident]) -> String {
4574 let mut result = String::new();
4575 for (i, ident) in idents.iter()
4576 .filter(|ident| ident.name != keywords::CrateRoot.name())
4579 result.push_str("::");
4581 result.push_str(&ident.as_str());
4586 fn path_names_to_string(path: &Path) -> String {
4587 names_to_string(&path.segments.iter()
4588 .map(|seg| seg.ident)
4589 .collect::<Vec<_>>())
4592 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4593 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4594 let variant_path = &suggestion.path;
4595 let variant_path_string = path_names_to_string(variant_path);
4597 let path_len = suggestion.path.segments.len();
4598 let enum_path = ast::Path {
4599 span: suggestion.path.span,
4600 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4602 let enum_path_string = path_names_to_string(&enum_path);
4604 (suggestion.path.span, variant_path_string, enum_path_string)
4608 /// When an entity with a given name is not available in scope, we search for
4609 /// entities with that name in all crates. This method allows outputting the
4610 /// results of this search in a programmer-friendly way
4611 fn show_candidates(err: &mut DiagnosticBuilder,
4612 // This is `None` if all placement locations are inside expansions
4614 candidates: &[ImportSuggestion],
4618 // we want consistent results across executions, but candidates are produced
4619 // by iterating through a hash map, so make sure they are ordered:
4620 let mut path_strings: Vec<_> =
4621 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4622 path_strings.sort();
4624 let better = if better { "better " } else { "" };
4625 let msg_diff = match path_strings.len() {
4626 1 => " is found in another module, you can import it",
4627 _ => "s are found in other modules, you can import them",
4629 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4631 if let Some(span) = span {
4632 for candidate in &mut path_strings {
4633 // produce an additional newline to separate the new use statement
4634 // from the directly following item.
4635 let additional_newline = if found_use {
4640 *candidate = format!("use {};\n{}", candidate, additional_newline);
4643 err.span_suggestions(span, &msg, path_strings);
4647 for candidate in path_strings {
4649 msg.push_str(&candidate);
4654 /// A somewhat inefficient routine to obtain the name of a module.
4655 fn module_to_string(module: Module) -> Option<String> {
4656 let mut names = Vec::new();
4658 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4659 if let ModuleKind::Def(_, name) = module.kind {
4660 if let Some(parent) = module.parent {
4661 names.push(Ident::with_empty_ctxt(name));
4662 collect_mod(names, parent);
4665 // danger, shouldn't be ident?
4666 names.push(Ident::from_str("<opaque>"));
4667 collect_mod(names, module.parent.unwrap());
4670 collect_mod(&mut names, module);
4672 if names.is_empty() {
4675 Some(names_to_string(&names.into_iter()
4677 .collect::<Vec<_>>()))
4680 fn err_path_resolution() -> PathResolution {
4681 PathResolution::new(Def::Err)
4684 #[derive(PartialEq,Copy, Clone)]
4685 pub enum MakeGlobMap {
4690 #[derive(Copy, Clone, Debug)]
4692 /// Do not issue the lint
4695 /// This lint applies to some random path like `impl ::foo::Bar`
4696 /// or whatever. In this case, we can take the span of that path.
4699 /// This lint comes from a `use` statement. In this case, what we
4700 /// care about really is the *root* `use` statement; e.g., if we
4701 /// have nested things like `use a::{b, c}`, we care about the
4703 UsePath { root_id: NodeId, root_span: Span },
4705 /// This is the "trait item" from a fully qualified path. For example,
4706 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4707 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4708 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4712 fn node_id(&self) -> Option<NodeId> {
4714 CrateLint::No => None,
4715 CrateLint::SimplePath(id) |
4716 CrateLint::UsePath { root_id: id, .. } |
4717 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4722 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }