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)]
17 #![feature(rustc_diagnostic_macros)]
18 #![feature(slice_sort_by_cached_key)]
21 extern crate bitflags;
26 extern crate syntax_pos;
27 extern crate rustc_errors as errors;
31 extern crate rustc_data_structures;
32 extern crate rustc_metadata;
34 pub use rustc::hir::def::{Namespace, PerNS};
36 use self::TypeParameters::*;
39 use rustc::hir::map::{Definitions, DefCollector};
40 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
41 use rustc::middle::cstore::CrateStore;
42 use rustc::session::Session;
44 use rustc::hir::def::*;
45 use rustc::hir::def::Namespace::*;
46 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
47 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
48 use rustc::session::config::nightly_options;
50 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
52 use rustc_metadata::creader::CrateLoader;
53 use rustc_metadata::cstore::CStore;
55 use syntax::source_map::SourceMap;
56 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
57 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
58 use syntax::ext::base::SyntaxExtension;
59 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
60 use syntax::ext::base::MacroKind;
61 use syntax::feature_gate::{emit_feature_err, GateIssue};
62 use syntax::symbol::{Symbol, keywords};
63 use syntax::util::lev_distance::find_best_match_for_name;
65 use syntax::visit::{self, FnKind, Visitor};
67 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
68 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
69 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
70 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
71 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
74 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
75 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
77 use std::cell::{Cell, RefCell};
78 use std::{cmp, fmt, iter, ptr};
79 use std::collections::BTreeSet;
80 use std::mem::replace;
81 use rustc_data_structures::ptr_key::PtrKey;
82 use rustc_data_structures::sync::Lrc;
84 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
85 use macros::{InvocationData, LegacyBinding, ParentScope};
87 // NB: This module needs to be declared first so diagnostics are
88 // registered before they are used.
93 mod build_reduced_graph;
96 fn is_known_tool(name: Name) -> bool {
97 ["clippy", "rustfmt"].contains(&&*name.as_str())
100 /// A free importable items suggested in case of resolution failure.
101 struct ImportSuggestion {
105 /// A field or associated item from self type suggested in case of resolution failure.
106 enum AssocSuggestion {
113 struct BindingError {
115 origin: BTreeSet<Span>,
116 target: BTreeSet<Span>,
119 impl PartialOrd for BindingError {
120 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
121 Some(self.cmp(other))
125 impl PartialEq for BindingError {
126 fn eq(&self, other: &BindingError) -> bool {
127 self.name == other.name
131 impl Ord for BindingError {
132 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
133 self.name.cmp(&other.name)
137 enum ResolutionError<'a> {
138 /// error E0401: can't use type parameters from outer function
139 TypeParametersFromOuterFunction(Def),
140 /// error E0403: the name is already used for a type parameter in this type parameter list
141 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
142 /// error E0407: method is not a member of trait
143 MethodNotMemberOfTrait(Name, &'a str),
144 /// error E0437: type is not a member of trait
145 TypeNotMemberOfTrait(Name, &'a str),
146 /// error E0438: const is not a member of trait
147 ConstNotMemberOfTrait(Name, &'a str),
148 /// error E0408: variable `{}` is not bound in all patterns
149 VariableNotBoundInPattern(&'a BindingError),
150 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
151 VariableBoundWithDifferentMode(Name, Span),
152 /// error E0415: identifier is bound more than once in this parameter list
153 IdentifierBoundMoreThanOnceInParameterList(&'a str),
154 /// error E0416: identifier is bound more than once in the same pattern
155 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
156 /// error E0426: use of undeclared label
157 UndeclaredLabel(&'a str, Option<Name>),
158 /// error E0429: `self` imports are only allowed within a { } list
159 SelfImportsOnlyAllowedWithin,
160 /// error E0430: `self` import can only appear once in the list
161 SelfImportCanOnlyAppearOnceInTheList,
162 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
163 SelfImportOnlyInImportListWithNonEmptyPrefix,
164 /// error E0433: failed to resolve
165 FailedToResolve(&'a str),
166 /// error E0434: can't capture dynamic environment in a fn item
167 CannotCaptureDynamicEnvironmentInFnItem,
168 /// error E0435: attempt to use a non-constant value in a constant
169 AttemptToUseNonConstantValueInConstant,
170 /// error E0530: X bindings cannot shadow Ys
171 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
172 /// error E0128: type parameters with a default cannot use forward declared identifiers
173 ForwardDeclaredTyParam,
176 /// Combines an error with provided span and emits it
178 /// This takes the error provided, combines it with the span and any additional spans inside the
179 /// error and emits it.
180 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
182 resolution_error: ResolutionError<'a>) {
183 resolve_struct_error(resolver, span, resolution_error).emit();
186 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
188 resolution_error: ResolutionError<'a>)
189 -> DiagnosticBuilder<'sess> {
190 match resolution_error {
191 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
192 let mut err = struct_span_err!(resolver.session,
195 "can't use type parameters from outer function");
196 err.span_label(span, "use of type variable from outer function");
198 let cm = resolver.session.source_map();
200 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
201 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
202 resolver.definitions.opt_span(def_id)
205 reduce_impl_span_to_impl_keyword(cm, impl_span),
206 "`Self` type implicitly declared here, by this `impl`",
209 match (maybe_trait_defid, maybe_impl_defid) {
211 err.span_label(span, "can't use `Self` here");
214 err.span_label(span, "use a type here instead");
216 (None, None) => bug!("`impl` without trait nor type?"),
220 Def::TyParam(typaram_defid) => {
221 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
222 err.span_label(typaram_span, "type variable from outer function");
226 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
231 // Try to retrieve the span of the function signature and generate a new message with
232 // a local type parameter
233 let sugg_msg = "try using a local type parameter instead";
234 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
235 // Suggest the modification to the user
236 err.span_suggestion_with_applicability(
240 Applicability::MachineApplicable,
242 } else if let Some(sp) = cm.generate_fn_name_span(span) {
243 err.span_label(sp, "try adding a local type parameter in this method instead");
245 err.help("try using a local type parameter instead");
250 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
251 let mut err = struct_span_err!(resolver.session,
254 "the name `{}` is already used for a type parameter \
255 in this type parameter list",
257 err.span_label(span, "already used");
258 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
261 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
262 let mut err = struct_span_err!(resolver.session,
265 "method `{}` is not a member of trait `{}`",
268 err.span_label(span, format!("not a member of trait `{}`", trait_));
271 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
272 let mut err = struct_span_err!(resolver.session,
275 "type `{}` is not a member of trait `{}`",
278 err.span_label(span, format!("not a member of trait `{}`", trait_));
281 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
282 let mut err = struct_span_err!(resolver.session,
285 "const `{}` is not a member of trait `{}`",
288 err.span_label(span, format!("not a member of trait `{}`", trait_));
291 ResolutionError::VariableNotBoundInPattern(binding_error) => {
292 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
293 let msp = MultiSpan::from_spans(target_sp.clone());
294 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
295 let mut err = resolver.session.struct_span_err_with_code(
298 DiagnosticId::Error("E0408".into()),
300 for sp in target_sp {
301 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
303 let origin_sp = binding_error.origin.iter().cloned();
304 for sp in origin_sp {
305 err.span_label(sp, "variable not in all patterns");
309 ResolutionError::VariableBoundWithDifferentMode(variable_name,
310 first_binding_span) => {
311 let mut err = struct_span_err!(resolver.session,
314 "variable `{}` is bound in inconsistent \
315 ways within the same match arm",
317 err.span_label(span, "bound in different ways");
318 err.span_label(first_binding_span, "first binding");
321 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
322 let mut err = struct_span_err!(resolver.session,
325 "identifier `{}` is bound more than once in this parameter list",
327 err.span_label(span, "used as parameter more than once");
330 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
331 let mut err = struct_span_err!(resolver.session,
334 "identifier `{}` is bound more than once in the same pattern",
336 err.span_label(span, "used in a pattern more than once");
339 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
340 let mut err = struct_span_err!(resolver.session,
343 "use of undeclared label `{}`",
345 if let Some(lev_candidate) = lev_candidate {
346 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
348 err.span_label(span, format!("undeclared label `{}`", name));
352 ResolutionError::SelfImportsOnlyAllowedWithin => {
353 struct_span_err!(resolver.session,
357 "`self` imports are only allowed within a { } list")
359 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
360 let mut err = struct_span_err!(resolver.session, span, E0430,
361 "`self` import can only appear once in an import list");
362 err.span_label(span, "can only appear once in an import list");
365 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
366 let mut err = struct_span_err!(resolver.session, span, E0431,
367 "`self` import can only appear in an import list with \
368 a non-empty prefix");
369 err.span_label(span, "can only appear in an import list with a non-empty prefix");
372 ResolutionError::FailedToResolve(msg) => {
373 let mut err = struct_span_err!(resolver.session, span, E0433,
374 "failed to resolve. {}", msg);
375 err.span_label(span, msg);
378 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
379 let mut err = struct_span_err!(resolver.session,
383 "can't capture dynamic environment in a fn item");
384 err.help("use the `|| { ... }` closure form instead");
387 ResolutionError::AttemptToUseNonConstantValueInConstant => {
388 let mut err = struct_span_err!(resolver.session, span, E0435,
389 "attempt to use a non-constant value in a constant");
390 err.span_label(span, "non-constant value");
393 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
394 let shadows_what = PathResolution::new(binding.def()).kind_name();
395 let mut err = struct_span_err!(resolver.session,
398 "{}s cannot shadow {}s", what_binding, shadows_what);
399 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
400 let participle = if binding.is_import() { "imported" } else { "defined" };
401 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
402 err.span_label(binding.span, msg);
405 ResolutionError::ForwardDeclaredTyParam => {
406 let mut err = struct_span_err!(resolver.session, span, E0128,
407 "type parameters with a default cannot use \
408 forward declared identifiers");
410 span, "defaulted type parameters cannot be forward declared".to_string());
416 /// Adjust the impl span so that just the `impl` keyword is taken by removing
417 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
418 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
420 /// Attention: The method used is very fragile since it essentially duplicates the work of the
421 /// parser. If you need to use this function or something similar, please consider updating the
422 /// source_map functions and this function to something more robust.
423 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
424 let impl_span = cm.span_until_char(impl_span, '<');
425 let impl_span = cm.span_until_whitespace(impl_span);
429 #[derive(Copy, Clone, Debug)]
432 binding_mode: BindingMode,
435 /// Map from the name in a pattern to its binding mode.
436 type BindingMap = FxHashMap<Ident, BindingInfo>;
438 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
449 fn descr(self) -> &'static str {
451 PatternSource::Match => "match binding",
452 PatternSource::IfLet => "if let binding",
453 PatternSource::WhileLet => "while let binding",
454 PatternSource::Let => "let binding",
455 PatternSource::For => "for binding",
456 PatternSource::FnParam => "function parameter",
461 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
462 enum AliasPossibility {
467 #[derive(Copy, Clone, Debug)]
468 enum PathSource<'a> {
469 // Type paths `Path`.
471 // Trait paths in bounds or impls.
472 Trait(AliasPossibility),
473 // Expression paths `path`, with optional parent context.
474 Expr(Option<&'a Expr>),
475 // Paths in path patterns `Path`.
477 // Paths in struct expressions and patterns `Path { .. }`.
479 // Paths in tuple struct patterns `Path(..)`.
481 // `m::A::B` in `<T as m::A>::B::C`.
482 TraitItem(Namespace),
483 // Path in `pub(path)`
487 impl<'a> PathSource<'a> {
488 fn namespace(self) -> Namespace {
490 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
491 PathSource::Visibility => TypeNS,
492 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
493 PathSource::TraitItem(ns) => ns,
497 fn global_by_default(self) -> bool {
499 PathSource::Visibility => true,
500 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
501 PathSource::Struct | PathSource::TupleStruct |
502 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
506 fn defer_to_typeck(self) -> bool {
508 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
509 PathSource::Struct | PathSource::TupleStruct => true,
510 PathSource::Trait(_) | PathSource::TraitItem(..) |
511 PathSource::Visibility => false,
515 fn descr_expected(self) -> &'static str {
517 PathSource::Type => "type",
518 PathSource::Trait(_) => "trait",
519 PathSource::Pat => "unit struct/variant or constant",
520 PathSource::Struct => "struct, variant or union type",
521 PathSource::TupleStruct => "tuple struct/variant",
522 PathSource::Visibility => "module",
523 PathSource::TraitItem(ns) => match ns {
524 TypeNS => "associated type",
525 ValueNS => "method or associated constant",
526 MacroNS => bug!("associated macro"),
528 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
529 // "function" here means "anything callable" rather than `Def::Fn`,
530 // this is not precise but usually more helpful than just "value".
531 Some(&ExprKind::Call(..)) => "function",
537 fn is_expected(self, def: Def) -> bool {
539 PathSource::Type => match def {
540 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
541 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
542 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
543 Def::SelfTy(..) | Def::Existential(..) |
544 Def::ForeignTy(..) => true,
547 PathSource::Trait(AliasPossibility::No) => match def {
548 Def::Trait(..) => true,
551 PathSource::Trait(AliasPossibility::Maybe) => match def {
552 Def::Trait(..) => true,
553 Def::TraitAlias(..) => true,
556 PathSource::Expr(..) => match def {
557 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
558 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
559 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
560 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
561 Def::SelfCtor(..) => true,
564 PathSource::Pat => match def {
565 Def::StructCtor(_, CtorKind::Const) |
566 Def::VariantCtor(_, CtorKind::Const) |
567 Def::Const(..) | Def::AssociatedConst(..) |
568 Def::SelfCtor(..) => true,
571 PathSource::TupleStruct => match def {
572 Def::StructCtor(_, CtorKind::Fn) |
573 Def::VariantCtor(_, CtorKind::Fn) |
574 Def::SelfCtor(..) => true,
577 PathSource::Struct => match def {
578 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
579 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
582 PathSource::TraitItem(ns) => match def {
583 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
584 Def::AssociatedTy(..) if ns == TypeNS => true,
587 PathSource::Visibility => match def {
588 Def::Mod(..) => true,
594 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
595 __diagnostic_used!(E0404);
596 __diagnostic_used!(E0405);
597 __diagnostic_used!(E0412);
598 __diagnostic_used!(E0422);
599 __diagnostic_used!(E0423);
600 __diagnostic_used!(E0425);
601 __diagnostic_used!(E0531);
602 __diagnostic_used!(E0532);
603 __diagnostic_used!(E0573);
604 __diagnostic_used!(E0574);
605 __diagnostic_used!(E0575);
606 __diagnostic_used!(E0576);
607 __diagnostic_used!(E0577);
608 __diagnostic_used!(E0578);
609 match (self, has_unexpected_resolution) {
610 (PathSource::Trait(_), true) => "E0404",
611 (PathSource::Trait(_), false) => "E0405",
612 (PathSource::Type, true) => "E0573",
613 (PathSource::Type, false) => "E0412",
614 (PathSource::Struct, true) => "E0574",
615 (PathSource::Struct, false) => "E0422",
616 (PathSource::Expr(..), true) => "E0423",
617 (PathSource::Expr(..), false) => "E0425",
618 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
619 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
620 (PathSource::TraitItem(..), true) => "E0575",
621 (PathSource::TraitItem(..), false) => "E0576",
622 (PathSource::Visibility, true) => "E0577",
623 (PathSource::Visibility, false) => "E0578",
628 // A minimal representation of a path segment. We use this in resolve because
629 // we synthesize 'path segments' which don't have the rest of an AST or HIR
631 #[derive(Clone, Copy, Debug)]
638 fn from_path(path: &Path) -> Vec<Segment> {
639 path.segments.iter().map(|s| s.into()).collect()
642 fn from_ident(ident: Ident) -> Segment {
649 fn names_to_string(segments: &[Segment]) -> String {
650 names_to_string(&segments.iter()
651 .map(|seg| seg.ident)
652 .collect::<Vec<_>>())
656 impl<'a> From<&'a ast::PathSegment> for Segment {
657 fn from(seg: &'a ast::PathSegment) -> Segment {
665 struct UsePlacementFinder {
666 target_module: NodeId,
671 impl UsePlacementFinder {
672 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
673 let mut finder = UsePlacementFinder {
678 visit::walk_crate(&mut finder, krate);
679 (finder.span, finder.found_use)
683 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
686 module: &'tcx ast::Mod,
688 _: &[ast::Attribute],
691 if self.span.is_some() {
694 if node_id != self.target_module {
695 visit::walk_mod(self, module);
698 // find a use statement
699 for item in &module.items {
701 ItemKind::Use(..) => {
702 // don't suggest placing a use before the prelude
703 // import or other generated ones
704 if item.span.ctxt().outer().expn_info().is_none() {
705 self.span = Some(item.span.shrink_to_lo());
706 self.found_use = true;
710 // don't place use before extern crate
711 ItemKind::ExternCrate(_) => {}
712 // but place them before the first other item
713 _ => if self.span.map_or(true, |span| item.span < span ) {
714 if item.span.ctxt().outer().expn_info().is_none() {
715 // don't insert between attributes and an item
716 if item.attrs.is_empty() {
717 self.span = Some(item.span.shrink_to_lo());
719 // find the first attribute on the item
720 for attr in &item.attrs {
721 if self.span.map_or(true, |span| attr.span < span) {
722 self.span = Some(attr.span.shrink_to_lo());
733 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
734 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
735 fn visit_item(&mut self, item: &'tcx Item) {
736 self.resolve_item(item);
738 fn visit_arm(&mut self, arm: &'tcx Arm) {
739 self.resolve_arm(arm);
741 fn visit_block(&mut self, block: &'tcx Block) {
742 self.resolve_block(block);
744 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
745 self.with_constant_rib(|this| {
746 visit::walk_anon_const(this, constant);
749 fn visit_expr(&mut self, expr: &'tcx Expr) {
750 self.resolve_expr(expr, None);
752 fn visit_local(&mut self, local: &'tcx Local) {
753 self.resolve_local(local);
755 fn visit_ty(&mut self, ty: &'tcx Ty) {
757 TyKind::Path(ref qself, ref path) => {
758 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
760 TyKind::ImplicitSelf => {
761 let self_ty = keywords::SelfType.ident();
762 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
763 .map_or(Def::Err, |d| d.def());
764 self.record_def(ty.id, PathResolution::new(def));
768 visit::walk_ty(self, ty);
770 fn visit_poly_trait_ref(&mut self,
771 tref: &'tcx ast::PolyTraitRef,
772 m: &'tcx ast::TraitBoundModifier) {
773 self.smart_resolve_path(tref.trait_ref.ref_id, None,
774 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
775 visit::walk_poly_trait_ref(self, tref, m);
777 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
778 let type_parameters = match foreign_item.node {
779 ForeignItemKind::Fn(_, ref generics) => {
780 HasTypeParameters(generics, ItemRibKind)
782 ForeignItemKind::Static(..) => NoTypeParameters,
783 ForeignItemKind::Ty => NoTypeParameters,
784 ForeignItemKind::Macro(..) => NoTypeParameters,
786 self.with_type_parameter_rib(type_parameters, |this| {
787 visit::walk_foreign_item(this, foreign_item);
790 fn visit_fn(&mut self,
791 function_kind: FnKind<'tcx>,
792 declaration: &'tcx FnDecl,
796 let (rib_kind, asyncness) = match function_kind {
797 FnKind::ItemFn(_, ref header, ..) =>
798 (ItemRibKind, header.asyncness),
799 FnKind::Method(_, ref sig, _, _) =>
800 (TraitOrImplItemRibKind, sig.header.asyncness),
801 FnKind::Closure(_) =>
802 // Async closures aren't resolved through `visit_fn`-- they're
803 // processed separately
804 (ClosureRibKind(node_id), IsAsync::NotAsync),
807 // Create a value rib for the function.
808 self.ribs[ValueNS].push(Rib::new(rib_kind));
810 // Create a label rib for the function.
811 self.label_ribs.push(Rib::new(rib_kind));
813 // Add each argument to the rib.
814 let mut bindings_list = FxHashMap::default();
815 for argument in &declaration.inputs {
816 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
818 self.visit_ty(&argument.ty);
820 debug!("(resolving function) recorded argument");
822 visit::walk_fn_ret_ty(self, &declaration.output);
824 // Resolve the function body, potentially inside the body of an async closure
825 if let IsAsync::Async { closure_id, .. } = asyncness {
826 let rib_kind = ClosureRibKind(closure_id);
827 self.ribs[ValueNS].push(Rib::new(rib_kind));
828 self.label_ribs.push(Rib::new(rib_kind));
831 match function_kind {
832 FnKind::ItemFn(.., body) |
833 FnKind::Method(.., body) => {
834 self.visit_block(body);
836 FnKind::Closure(body) => {
837 self.visit_expr(body);
841 // Leave the body of the async closure
842 if asyncness.is_async() {
843 self.label_ribs.pop();
844 self.ribs[ValueNS].pop();
847 debug!("(resolving function) leaving function");
849 self.label_ribs.pop();
850 self.ribs[ValueNS].pop();
852 fn visit_generics(&mut self, generics: &'tcx Generics) {
853 // For type parameter defaults, we have to ban access
854 // to following type parameters, as the Substs can only
855 // provide previous type parameters as they're built. We
856 // put all the parameters on the ban list and then remove
857 // them one by one as they are processed and become available.
858 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
859 let mut found_default = false;
860 default_ban_rib.bindings.extend(generics.params.iter()
861 .filter_map(|param| match param.kind {
862 GenericParamKind::Lifetime { .. } => None,
863 GenericParamKind::Type { ref default, .. } => {
864 found_default |= default.is_some();
866 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
873 for param in &generics.params {
875 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
876 GenericParamKind::Type { ref default, .. } => {
877 for bound in ¶m.bounds {
878 self.visit_param_bound(bound);
881 if let Some(ref ty) = default {
882 self.ribs[TypeNS].push(default_ban_rib);
884 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
887 // Allow all following defaults to refer to this type parameter.
888 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
892 for p in &generics.where_clause.predicates {
893 self.visit_where_predicate(p);
898 #[derive(Copy, Clone)]
899 enum TypeParameters<'a, 'b> {
901 HasTypeParameters(// Type parameters.
904 // The kind of the rib used for type parameters.
908 /// The rib kind controls the translation of local
909 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
910 #[derive(Copy, Clone, Debug)]
912 /// No translation needs to be applied.
915 /// We passed through a closure scope at the given node ID.
916 /// Translate upvars as appropriate.
917 ClosureRibKind(NodeId /* func id */),
919 /// We passed through an impl or trait and are now in one of its
920 /// methods or associated types. Allow references to ty params that impl or trait
921 /// binds. Disallow any other upvars (including other ty params that are
923 TraitOrImplItemRibKind,
925 /// We passed through an item scope. Disallow upvars.
928 /// We're in a constant item. Can't refer to dynamic stuff.
931 /// We passed through a module.
932 ModuleRibKind(Module<'a>),
934 /// We passed through a `macro_rules!` statement
935 MacroDefinition(DefId),
937 /// All bindings in this rib are type parameters that can't be used
938 /// from the default of a type parameter because they're not declared
939 /// before said type parameter. Also see the `visit_generics` override.
940 ForwardTyParamBanRibKind,
945 /// A rib represents a scope names can live in. Note that these appear in many places, not just
946 /// around braces. At any place where the list of accessible names (of the given namespace)
947 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
948 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
951 /// Different [rib kinds](enum.RibKind) are transparent for different names.
953 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
954 /// resolving, the name is looked up from inside out.
957 bindings: FxHashMap<Ident, Def>,
962 fn new(kind: RibKind<'a>) -> Rib<'a> {
964 bindings: Default::default(),
970 /// An intermediate resolution result.
972 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
973 /// items are visible in their whole block, while defs only from the place they are defined
975 enum LexicalScopeBinding<'a> {
976 Item(&'a NameBinding<'a>),
980 impl<'a> LexicalScopeBinding<'a> {
981 fn item(self) -> Option<&'a NameBinding<'a>> {
983 LexicalScopeBinding::Item(binding) => Some(binding),
988 fn def(self) -> Def {
990 LexicalScopeBinding::Item(binding) => binding.def(),
991 LexicalScopeBinding::Def(def) => def,
996 #[derive(Copy, Clone, Debug)]
997 pub enum ModuleOrUniformRoot<'a> {
1001 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
1002 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
1003 /// but *not* `extern`), in the Rust 2018 edition.
1007 #[derive(Clone, Debug)]
1008 enum PathResult<'a> {
1009 Module(ModuleOrUniformRoot<'a>),
1010 NonModule(PathResolution),
1012 Failed(Span, String, bool /* is the error from the last segment? */),
1016 /// An anonymous module, eg. just a block.
1020 /// fn f() {} // (1)
1021 /// { // This is an anonymous module
1022 /// f(); // This resolves to (2) as we are inside the block.
1023 /// fn f() {} // (2)
1025 /// f(); // Resolves to (1)
1029 /// Any module with a name.
1033 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1034 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1039 /// One node in the tree of modules.
1040 pub struct ModuleData<'a> {
1041 parent: Option<Module<'a>>,
1044 // The def id of the closest normal module (`mod`) ancestor (including this module).
1045 normal_ancestor_id: DefId,
1047 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1048 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1049 Option<&'a NameBinding<'a>>)>>,
1050 macro_resolutions: RefCell<Vec<(Vec<Segment>, ParentScope<'a>, Span)>>,
1051 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1053 // Macro invocations that can expand into items in this module.
1054 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1056 no_implicit_prelude: bool,
1058 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1059 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1061 // Used to memoize the traits in this module for faster searches through all traits in scope.
1062 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1064 // Whether this module is populated. If not populated, any attempt to
1065 // access the children must be preceded with a
1066 // `populate_module_if_necessary` call.
1067 populated: Cell<bool>,
1069 /// Span of the module itself. Used for error reporting.
1075 type Module<'a> = &'a ModuleData<'a>;
1077 impl<'a> ModuleData<'a> {
1078 fn new(parent: Option<Module<'a>>,
1080 normal_ancestor_id: DefId,
1082 span: Span) -> Self {
1087 resolutions: Default::default(),
1088 legacy_macro_resolutions: RefCell::new(Vec::new()),
1089 macro_resolutions: RefCell::new(Vec::new()),
1090 builtin_attrs: RefCell::new(Vec::new()),
1091 unresolved_invocations: Default::default(),
1092 no_implicit_prelude: false,
1093 glob_importers: RefCell::new(Vec::new()),
1094 globs: RefCell::new(Vec::new()),
1095 traits: RefCell::new(None),
1096 populated: Cell::new(normal_ancestor_id.is_local()),
1102 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1103 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1104 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1108 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1109 let resolutions = self.resolutions.borrow();
1110 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1111 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1112 for &(&(ident, ns), &resolution) in resolutions.iter() {
1113 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1117 fn def(&self) -> Option<Def> {
1119 ModuleKind::Def(def, _) => Some(def),
1124 fn def_id(&self) -> Option<DefId> {
1125 self.def().as_ref().map(Def::def_id)
1128 // `self` resolves to the first module ancestor that `is_normal`.
1129 fn is_normal(&self) -> bool {
1131 ModuleKind::Def(Def::Mod(_), _) => true,
1136 fn is_trait(&self) -> bool {
1138 ModuleKind::Def(Def::Trait(_), _) => true,
1143 fn is_local(&self) -> bool {
1144 self.normal_ancestor_id.is_local()
1147 fn nearest_item_scope(&'a self) -> Module<'a> {
1148 if self.is_trait() { self.parent.unwrap() } else { self }
1151 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1152 while !ptr::eq(self, other) {
1153 if let Some(parent) = other.parent {
1163 impl<'a> fmt::Debug for ModuleData<'a> {
1164 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1165 write!(f, "{:?}", self.def())
1169 /// Records a possibly-private value, type, or module definition.
1170 #[derive(Clone, Debug)]
1171 pub struct NameBinding<'a> {
1172 kind: NameBindingKind<'a>,
1175 vis: ty::Visibility,
1178 pub trait ToNameBinding<'a> {
1179 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1182 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1183 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1188 #[derive(Clone, Debug)]
1189 enum NameBindingKind<'a> {
1190 Def(Def, /* is_macro_export */ bool),
1193 binding: &'a NameBinding<'a>,
1194 directive: &'a ImportDirective<'a>,
1198 b1: &'a NameBinding<'a>,
1199 b2: &'a NameBinding<'a>,
1203 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1205 struct UseError<'a> {
1206 err: DiagnosticBuilder<'a>,
1207 /// Attach `use` statements for these candidates
1208 candidates: Vec<ImportSuggestion>,
1209 /// The node id of the module to place the use statements in
1211 /// Whether the diagnostic should state that it's "better"
1215 struct AmbiguityError<'a> {
1217 b1: &'a NameBinding<'a>,
1218 b2: &'a NameBinding<'a>,
1221 impl<'a> NameBinding<'a> {
1222 fn module(&self) -> Option<Module<'a>> {
1224 NameBindingKind::Module(module) => Some(module),
1225 NameBindingKind::Import { binding, .. } => binding.module(),
1230 fn def(&self) -> Def {
1232 NameBindingKind::Def(def, _) => def,
1233 NameBindingKind::Module(module) => module.def().unwrap(),
1234 NameBindingKind::Import { binding, .. } => binding.def(),
1235 NameBindingKind::Ambiguity { .. } => Def::Err,
1239 fn def_ignoring_ambiguity(&self) -> Def {
1241 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1242 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1247 // We sometimes need to treat variants as `pub` for backwards compatibility
1248 fn pseudo_vis(&self) -> ty::Visibility {
1249 if self.is_variant() && self.def().def_id().is_local() {
1250 ty::Visibility::Public
1256 fn is_variant(&self) -> bool {
1258 NameBindingKind::Def(Def::Variant(..), _) |
1259 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1264 fn is_extern_crate(&self) -> bool {
1266 NameBindingKind::Import {
1267 directive: &ImportDirective {
1268 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1275 fn is_import(&self) -> bool {
1277 NameBindingKind::Import { .. } => true,
1282 fn is_glob_import(&self) -> bool {
1284 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1285 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1290 fn is_importable(&self) -> bool {
1292 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1297 fn is_macro_def(&self) -> bool {
1299 NameBindingKind::Def(Def::Macro(..), _) => true,
1304 fn macro_kind(&self) -> Option<MacroKind> {
1305 match self.def_ignoring_ambiguity() {
1306 Def::Macro(_, kind) => Some(kind),
1307 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1312 fn descr(&self) -> &'static str {
1313 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1316 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1317 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1318 // Then this function returns `true` if `self` may emerge from a macro *after* that
1319 // in some later round and screw up our previously found resolution.
1320 // See more detailed explanation in
1321 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1322 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1323 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1324 // Expansions are partially ordered, so "may appear after" is an inversion of
1325 // "certainly appears before or simultaneously" and includes unordered cases.
1326 let self_parent_expansion = self.expansion;
1327 let other_parent_expansion = binding.expansion;
1328 let certainly_before_other_or_simultaneously =
1329 other_parent_expansion.is_descendant_of(self_parent_expansion);
1330 let certainly_before_invoc_or_simultaneously =
1331 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1332 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1336 /// Interns the names of the primitive types.
1338 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1339 /// special handling, since they have no place of origin.
1341 struct PrimitiveTypeTable {
1342 primitive_types: FxHashMap<Name, PrimTy>,
1345 impl PrimitiveTypeTable {
1346 fn new() -> PrimitiveTypeTable {
1347 let mut table = PrimitiveTypeTable::default();
1349 table.intern("bool", Bool);
1350 table.intern("char", Char);
1351 table.intern("f32", Float(FloatTy::F32));
1352 table.intern("f64", Float(FloatTy::F64));
1353 table.intern("isize", Int(IntTy::Isize));
1354 table.intern("i8", Int(IntTy::I8));
1355 table.intern("i16", Int(IntTy::I16));
1356 table.intern("i32", Int(IntTy::I32));
1357 table.intern("i64", Int(IntTy::I64));
1358 table.intern("i128", Int(IntTy::I128));
1359 table.intern("str", Str);
1360 table.intern("usize", Uint(UintTy::Usize));
1361 table.intern("u8", Uint(UintTy::U8));
1362 table.intern("u16", Uint(UintTy::U16));
1363 table.intern("u32", Uint(UintTy::U32));
1364 table.intern("u64", Uint(UintTy::U64));
1365 table.intern("u128", Uint(UintTy::U128));
1369 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1370 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1374 #[derive(Default, Clone)]
1375 pub struct ExternPreludeEntry<'a> {
1376 extern_crate_item: Option<&'a NameBinding<'a>>,
1377 pub introduced_by_item: bool,
1380 /// The main resolver class.
1382 /// This is the visitor that walks the whole crate.
1383 pub struct Resolver<'a, 'b: 'a> {
1384 session: &'a Session,
1387 pub definitions: Definitions,
1389 graph_root: Module<'a>,
1391 prelude: Option<Module<'a>>,
1392 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1394 /// n.b. This is used only for better diagnostics, not name resolution itself.
1395 has_self: FxHashSet<DefId>,
1397 /// Names of fields of an item `DefId` accessible with dot syntax.
1398 /// Used for hints during error reporting.
1399 field_names: FxHashMap<DefId, Vec<Name>>,
1401 /// All imports known to succeed or fail.
1402 determined_imports: Vec<&'a ImportDirective<'a>>,
1404 /// All non-determined imports.
1405 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1407 /// The module that represents the current item scope.
1408 current_module: Module<'a>,
1410 /// The current set of local scopes for types and values.
1411 /// FIXME #4948: Reuse ribs to avoid allocation.
1412 ribs: PerNS<Vec<Rib<'a>>>,
1414 /// The current set of local scopes, for labels.
1415 label_ribs: Vec<Rib<'a>>,
1417 /// The trait that the current context can refer to.
1418 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1420 /// The current self type if inside an impl (used for better errors).
1421 current_self_type: Option<Ty>,
1423 /// The current self item if inside an ADT (used for better errors).
1424 current_self_item: Option<NodeId>,
1426 /// The idents for the primitive types.
1427 primitive_type_table: PrimitiveTypeTable,
1430 import_map: ImportMap,
1431 pub freevars: FreevarMap,
1432 freevars_seen: NodeMap<NodeMap<usize>>,
1433 pub export_map: ExportMap,
1434 pub trait_map: TraitMap,
1436 /// A map from nodes to anonymous modules.
1437 /// Anonymous modules are pseudo-modules that are implicitly created around items
1438 /// contained within blocks.
1440 /// For example, if we have this:
1448 /// There will be an anonymous module created around `g` with the ID of the
1449 /// entry block for `f`.
1450 block_map: NodeMap<Module<'a>>,
1451 module_map: FxHashMap<DefId, Module<'a>>,
1452 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1453 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1455 pub make_glob_map: bool,
1456 /// Maps imports to the names of items actually imported (this actually maps
1457 /// all imports, but only glob imports are actually interesting).
1458 pub glob_map: GlobMap,
1460 used_imports: FxHashSet<(NodeId, Namespace)>,
1461 pub maybe_unused_trait_imports: NodeSet,
1462 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1464 /// A list of labels as of yet unused. Labels will be removed from this map when
1465 /// they are used (in a `break` or `continue` statement)
1466 pub unused_labels: FxHashMap<NodeId, Span>,
1468 /// privacy errors are delayed until the end in order to deduplicate them
1469 privacy_errors: Vec<PrivacyError<'a>>,
1470 /// ambiguity errors are delayed for deduplication
1471 ambiguity_errors: Vec<AmbiguityError<'a>>,
1472 /// `use` injections are delayed for better placement and deduplication
1473 use_injections: Vec<UseError<'a>>,
1474 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1475 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1477 arenas: &'a ResolverArenas<'a>,
1478 dummy_binding: &'a NameBinding<'a>,
1480 crate_loader: &'a mut CrateLoader<'b>,
1481 macro_names: FxHashSet<Ident>,
1482 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1483 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1484 pub all_macros: FxHashMap<Name, Def>,
1485 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1486 macro_defs: FxHashMap<Mark, DefId>,
1487 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1488 pub whitelisted_legacy_custom_derives: Vec<Name>,
1489 pub found_unresolved_macro: bool,
1491 /// List of crate local macros that we need to warn about as being unused.
1492 /// Right now this only includes macro_rules! macros, and macros 2.0.
1493 unused_macros: FxHashSet<DefId>,
1495 /// Maps the `Mark` of an expansion to its containing module or block.
1496 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1498 /// Avoid duplicated errors for "name already defined".
1499 name_already_seen: FxHashMap<Name, Span>,
1501 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1503 /// This table maps struct IDs into struct constructor IDs,
1504 /// it's not used during normal resolution, only for better error reporting.
1505 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1507 /// Only used for better errors on `fn(): fn()`
1508 current_type_ascription: Vec<Span>,
1510 injected_crate: Option<Module<'a>>,
1513 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1515 pub struct ResolverArenas<'a> {
1516 modules: arena::TypedArena<ModuleData<'a>>,
1517 local_modules: RefCell<Vec<Module<'a>>>,
1518 name_bindings: arena::TypedArena<NameBinding<'a>>,
1519 import_directives: arena::TypedArena<ImportDirective<'a>>,
1520 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1521 invocation_data: arena::TypedArena<InvocationData<'a>>,
1522 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1525 impl<'a> ResolverArenas<'a> {
1526 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1527 let module = self.modules.alloc(module);
1528 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1529 self.local_modules.borrow_mut().push(module);
1533 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1534 self.local_modules.borrow()
1536 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1537 self.name_bindings.alloc(name_binding)
1539 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1540 -> &'a ImportDirective {
1541 self.import_directives.alloc(import_directive)
1543 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1544 self.name_resolutions.alloc(Default::default())
1546 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1547 -> &'a InvocationData<'a> {
1548 self.invocation_data.alloc(expansion_data)
1550 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1551 self.legacy_bindings.alloc(binding)
1555 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1556 fn parent(self, id: DefId) -> Option<DefId> {
1558 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1559 _ => self.cstore.def_key(id).parent,
1560 }.map(|index| DefId { index, ..id })
1564 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1565 /// the resolver is no longer needed as all the relevant information is inline.
1566 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1567 fn resolve_hir_path(
1572 self.resolve_hir_path_cb(path, is_value,
1573 |resolver, span, error| resolve_error(resolver, span, error))
1576 fn resolve_str_path(
1579 crate_root: Option<&str>,
1580 components: &[&str],
1583 let segments = iter::once(keywords::CrateRoot.ident())
1585 crate_root.into_iter()
1586 .chain(components.iter().cloned())
1587 .map(Ident::from_str)
1588 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1591 let path = ast::Path {
1596 self.resolve_hir_path(&path, is_value)
1599 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1600 self.def_map.get(&id).cloned()
1603 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1604 self.import_map.get(&id).cloned().unwrap_or_default()
1607 fn definitions(&mut self) -> &mut Definitions {
1608 &mut self.definitions
1612 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1613 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1614 /// isn't something that can be returned because it can't be made to live that long,
1615 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1616 /// just that an error occurred.
1617 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1618 -> Result<hir::Path, ()> {
1620 let mut errored = false;
1622 let path = if path_str.starts_with("::") {
1625 segments: iter::once(keywords::CrateRoot.ident())
1627 path_str.split("::").skip(1).map(Ident::from_str)
1629 .map(|i| self.new_ast_path_segment(i))
1637 .map(Ident::from_str)
1638 .map(|i| self.new_ast_path_segment(i))
1642 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1643 if errored || path.def == Def::Err {
1650 /// resolve_hir_path, but takes a callback in case there was an error
1651 fn resolve_hir_path_cb<F>(
1657 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1659 let namespace = if is_value { ValueNS } else { TypeNS };
1660 let span = path.span;
1661 let segments = &path.segments;
1662 let path = Segment::from_path(&path);
1663 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1664 let def = match self.resolve_path_without_parent_scope(None, &path, Some(namespace),
1665 true, span, CrateLint::No) {
1666 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1667 module.def().unwrap(),
1668 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1669 path_res.base_def(),
1670 PathResult::NonModule(..) => {
1671 let msg = "type-relative paths are not supported in this context";
1672 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1675 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1676 PathResult::Indeterminate => unreachable!(),
1677 PathResult::Failed(span, msg, _) => {
1678 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1683 let segments: Vec<_> = segments.iter().map(|seg| {
1684 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1685 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1691 segments: segments.into(),
1695 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1696 let mut seg = ast::PathSegment::from_ident(ident);
1697 seg.id = self.session.next_node_id();
1702 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1703 pub fn new(session: &'a Session,
1707 make_glob_map: MakeGlobMap,
1708 crate_loader: &'a mut CrateLoader<'crateloader>,
1709 arenas: &'a ResolverArenas<'a>)
1710 -> Resolver<'a, 'crateloader> {
1711 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1712 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1713 let graph_root = arenas.alloc_module(ModuleData {
1714 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1715 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1717 let mut module_map = FxHashMap::default();
1718 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1720 let mut definitions = Definitions::new();
1721 DefCollector::new(&mut definitions, Mark::root())
1722 .collect_root(crate_name, session.local_crate_disambiguator());
1724 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1725 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1728 if !attr::contains_name(&krate.attrs, "no_core") {
1729 extern_prelude.insert(Ident::from_str("core"), Default::default());
1730 if !attr::contains_name(&krate.attrs, "no_std") {
1731 extern_prelude.insert(Ident::from_str("std"), Default::default());
1732 if session.rust_2018() {
1733 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1738 let mut invocations = FxHashMap::default();
1739 invocations.insert(Mark::root(),
1740 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1742 let mut macro_defs = FxHashMap::default();
1743 macro_defs.insert(Mark::root(), root_def_id);
1752 // The outermost module has def ID 0; this is not reflected in the
1758 has_self: FxHashSet::default(),
1759 field_names: FxHashMap::default(),
1761 determined_imports: Vec::new(),
1762 indeterminate_imports: Vec::new(),
1764 current_module: graph_root,
1766 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1767 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1768 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1770 label_ribs: Vec::new(),
1772 current_trait_ref: None,
1773 current_self_type: None,
1774 current_self_item: None,
1776 primitive_type_table: PrimitiveTypeTable::new(),
1779 import_map: NodeMap(),
1780 freevars: NodeMap(),
1781 freevars_seen: NodeMap(),
1782 export_map: FxHashMap::default(),
1783 trait_map: NodeMap(),
1785 block_map: NodeMap(),
1786 extern_module_map: FxHashMap::default(),
1787 binding_parent_modules: FxHashMap::default(),
1789 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1790 glob_map: NodeMap(),
1792 used_imports: FxHashSet::default(),
1793 maybe_unused_trait_imports: NodeSet(),
1794 maybe_unused_extern_crates: Vec::new(),
1796 unused_labels: FxHashMap::default(),
1798 privacy_errors: Vec::new(),
1799 ambiguity_errors: Vec::new(),
1800 use_injections: Vec::new(),
1801 macro_expanded_macro_export_errors: BTreeSet::new(),
1804 dummy_binding: arenas.alloc_name_binding(NameBinding {
1805 kind: NameBindingKind::Def(Def::Err, false),
1806 expansion: Mark::root(),
1808 vis: ty::Visibility::Public,
1812 macro_names: FxHashSet::default(),
1813 builtin_macros: FxHashMap::default(),
1814 macro_use_prelude: FxHashMap::default(),
1815 all_macros: FxHashMap::default(),
1816 macro_map: FxHashMap::default(),
1819 local_macro_def_scopes: FxHashMap::default(),
1820 name_already_seen: FxHashMap::default(),
1821 whitelisted_legacy_custom_derives: Vec::new(),
1822 potentially_unused_imports: Vec::new(),
1823 struct_constructors: DefIdMap(),
1824 found_unresolved_macro: false,
1825 unused_macros: FxHashSet::default(),
1826 current_type_ascription: Vec::new(),
1827 injected_crate: None,
1831 pub fn arenas() -> ResolverArenas<'a> {
1835 /// Runs the function on each namespace.
1836 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1842 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1844 match self.macro_defs.get(&ctxt.outer()) {
1845 Some(&def_id) => return def_id,
1846 None => ctxt.remove_mark(),
1851 /// Entry point to crate resolution.
1852 pub fn resolve_crate(&mut self, krate: &Crate) {
1853 ImportResolver { resolver: self }.finalize_imports();
1854 self.current_module = self.graph_root;
1855 self.finalize_current_module_macro_resolutions();
1857 visit::walk_crate(self, krate);
1859 check_unused::check_crate(self, krate);
1860 self.report_errors(krate);
1861 self.crate_loader.postprocess(krate);
1868 normal_ancestor_id: DefId,
1872 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1873 self.arenas.alloc_module(module)
1876 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1877 -> bool /* true if an error was reported */ {
1878 match binding.kind {
1879 NameBindingKind::Import { directive, binding, ref used }
1882 directive.used.set(true);
1883 self.used_imports.insert((directive.id, ns));
1884 self.add_to_glob_map(directive.id, ident);
1885 self.record_use(ident, ns, binding)
1887 NameBindingKind::Import { .. } => false,
1888 NameBindingKind::Ambiguity { b1, b2 } => {
1889 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1896 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1897 if self.make_glob_map {
1898 self.glob_map.entry(id).or_default().insert(ident.name);
1902 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1903 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1904 /// `ident` in the first scope that defines it (or None if no scopes define it).
1906 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1907 /// the items are defined in the block. For example,
1910 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1913 /// g(); // This resolves to the local variable `g` since it shadows the item.
1917 /// Invariant: This must only be called during main resolution, not during
1918 /// import resolution.
1919 fn resolve_ident_in_lexical_scope(&mut self,
1922 record_used_id: Option<NodeId>,
1924 -> Option<LexicalScopeBinding<'a>> {
1925 let record_used = record_used_id.is_some();
1926 assert!(ns == TypeNS || ns == ValueNS);
1928 ident.span = if ident.name == keywords::SelfType.name() {
1929 // FIXME(jseyfried) improve `Self` hygiene
1930 ident.span.with_ctxt(SyntaxContext::empty())
1935 ident = ident.modern_and_legacy();
1938 // Walk backwards up the ribs in scope.
1939 let mut module = self.graph_root;
1940 for i in (0 .. self.ribs[ns].len()).rev() {
1941 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1942 // The ident resolves to a type parameter or local variable.
1943 return Some(LexicalScopeBinding::Def(
1944 self.adjust_local_def(ns, i, def, record_used, path_span)
1948 module = match self.ribs[ns][i].kind {
1949 ModuleRibKind(module) => module,
1950 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1951 // If an invocation of this macro created `ident`, give up on `ident`
1952 // and switch to `ident`'s source from the macro definition.
1953 ident.span.remove_mark();
1959 let item = self.resolve_ident_in_module_unadjusted(
1960 ModuleOrUniformRoot::Module(module),
1967 if let Ok(binding) = item {
1968 // The ident resolves to an item.
1969 return Some(LexicalScopeBinding::Item(binding));
1973 ModuleKind::Block(..) => {}, // We can see through blocks
1978 ident.span = ident.span.modern();
1979 let mut poisoned = None;
1981 let opt_module = if let Some(node_id) = record_used_id {
1982 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1983 node_id, &mut poisoned)
1985 self.hygienic_lexical_parent(module, &mut ident.span)
1987 module = unwrap_or!(opt_module, break);
1988 let orig_current_module = self.current_module;
1989 self.current_module = module; // Lexical resolutions can never be a privacy error.
1990 let result = self.resolve_ident_in_module_unadjusted(
1991 ModuleOrUniformRoot::Module(module),
1998 self.current_module = orig_current_module;
2002 if let Some(node_id) = poisoned {
2003 self.session.buffer_lint_with_diagnostic(
2004 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2005 node_id, ident.span,
2006 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2007 lint::builtin::BuiltinLintDiagnostics::
2008 ProcMacroDeriveResolutionFallback(ident.span),
2011 return Some(LexicalScopeBinding::Item(binding))
2013 Err(Determined) => continue,
2014 Err(Undetermined) =>
2015 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2019 if !module.no_implicit_prelude {
2021 if let Some(binding) = self.extern_prelude_get(ident, !record_used, false) {
2022 return Some(LexicalScopeBinding::Item(binding));
2025 if ns == TypeNS && is_known_tool(ident.name) {
2026 let binding = (Def::ToolMod, ty::Visibility::Public,
2027 ident.span, Mark::root()).to_name_binding(self.arenas);
2028 return Some(LexicalScopeBinding::Item(binding));
2030 if let Some(prelude) = self.prelude {
2031 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2032 ModuleOrUniformRoot::Module(prelude),
2039 return Some(LexicalScopeBinding::Item(binding));
2047 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2048 -> Option<Module<'a>> {
2049 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2050 return Some(self.macro_def_scope(span.remove_mark()));
2053 if let ModuleKind::Block(..) = module.kind {
2054 return Some(module.parent.unwrap());
2060 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2061 span: &mut Span, node_id: NodeId,
2062 poisoned: &mut Option<NodeId>)
2063 -> Option<Module<'a>> {
2064 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2068 // We need to support the next case under a deprecation warning
2071 // ---- begin: this comes from a proc macro derive
2072 // mod implementation_details {
2073 // // Note that `MyStruct` is not in scope here.
2074 // impl SomeTrait for MyStruct { ... }
2078 // So we have to fall back to the module's parent during lexical resolution in this case.
2079 if let Some(parent) = module.parent {
2080 // Inner module is inside the macro, parent module is outside of the macro.
2081 if module.expansion != parent.expansion &&
2082 module.expansion.is_descendant_of(parent.expansion) {
2083 // The macro is a proc macro derive
2084 if module.expansion.looks_like_proc_macro_derive() {
2085 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2086 *poisoned = Some(node_id);
2087 return module.parent;
2096 fn resolve_ident_in_module(&mut self,
2097 module: ModuleOrUniformRoot<'a>,
2102 -> Result<&'a NameBinding<'a>, Determinacy> {
2103 ident.span = ident.span.modern();
2104 let orig_current_module = self.current_module;
2105 if let ModuleOrUniformRoot::Module(module) = module {
2106 if let Some(def) = ident.span.adjust(module.expansion) {
2107 self.current_module = self.macro_def_scope(def);
2110 let result = self.resolve_ident_in_module_unadjusted(
2111 module, ident, ns, false, record_used, span,
2113 self.current_module = orig_current_module;
2117 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2118 let mut ctxt = ident.span.ctxt();
2119 let mark = if ident.name == keywords::DollarCrate.name() {
2120 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2121 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2122 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2123 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2124 // definitions actually produced by `macro` and `macro` definitions produced by
2125 // `macro_rules!`, but at least such configurations are not stable yet.
2126 ctxt = ctxt.modern_and_legacy();
2127 let mut iter = ctxt.marks().into_iter().rev().peekable();
2128 let mut result = None;
2129 // Find the last modern mark from the end if it exists.
2130 while let Some(&(mark, transparency)) = iter.peek() {
2131 if transparency == Transparency::Opaque {
2132 result = Some(mark);
2138 // Then find the last legacy mark from the end if it exists.
2139 for (mark, transparency) in iter {
2140 if transparency == Transparency::SemiTransparent {
2141 result = Some(mark);
2148 ctxt = ctxt.modern();
2149 ctxt.adjust(Mark::root())
2151 let module = match mark {
2152 Some(def) => self.macro_def_scope(def),
2153 None => return self.graph_root,
2155 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2158 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2159 let mut module = self.get_module(module.normal_ancestor_id);
2160 while module.span.ctxt().modern() != *ctxt {
2161 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2162 module = self.get_module(parent.normal_ancestor_id);
2169 // We maintain a list of value ribs and type ribs.
2171 // Simultaneously, we keep track of the current position in the module
2172 // graph in the `current_module` pointer. When we go to resolve a name in
2173 // the value or type namespaces, we first look through all the ribs and
2174 // then query the module graph. When we resolve a name in the module
2175 // namespace, we can skip all the ribs (since nested modules are not
2176 // allowed within blocks in Rust) and jump straight to the current module
2179 // Named implementations are handled separately. When we find a method
2180 // call, we consult the module node to find all of the implementations in
2181 // scope. This information is lazily cached in the module node. We then
2182 // generate a fake "implementation scope" containing all the
2183 // implementations thus found, for compatibility with old resolve pass.
2185 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2186 where F: FnOnce(&mut Resolver) -> T
2188 let id = self.definitions.local_def_id(id);
2189 let module = self.module_map.get(&id).cloned(); // clones a reference
2190 if let Some(module) = module {
2191 // Move down in the graph.
2192 let orig_module = replace(&mut self.current_module, module);
2193 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2194 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2196 self.finalize_current_module_macro_resolutions();
2199 self.current_module = orig_module;
2200 self.ribs[ValueNS].pop();
2201 self.ribs[TypeNS].pop();
2208 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2209 /// is returned by the given predicate function
2211 /// Stops after meeting a closure.
2212 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2213 where P: Fn(&Rib, Ident) -> Option<R>
2215 for rib in self.label_ribs.iter().rev() {
2218 // If an invocation of this macro created `ident`, give up on `ident`
2219 // and switch to `ident`'s source from the macro definition.
2220 MacroDefinition(def) => {
2221 if def == self.macro_def(ident.span.ctxt()) {
2222 ident.span.remove_mark();
2226 // Do not resolve labels across function boundary
2230 let r = pred(rib, ident);
2238 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2239 self.with_current_self_item(item, |this| {
2240 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2241 let item_def_id = this.definitions.local_def_id(item.id);
2242 if this.session.features_untracked().self_in_typedefs {
2243 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2244 visit::walk_item(this, item);
2247 visit::walk_item(this, item);
2253 fn resolve_item(&mut self, item: &Item) {
2254 let name = item.ident.name;
2255 debug!("(resolving item) resolving {}", name);
2258 ItemKind::Ty(_, ref generics) |
2259 ItemKind::Fn(_, _, ref generics, _) |
2260 ItemKind::Existential(_, ref generics) => {
2261 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2262 |this| visit::walk_item(this, item));
2265 ItemKind::Enum(_, ref generics) |
2266 ItemKind::Struct(_, ref generics) |
2267 ItemKind::Union(_, ref generics) => {
2268 self.resolve_adt(item, generics);
2271 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2272 self.resolve_implementation(generics,
2278 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2279 // Create a new rib for the trait-wide type parameters.
2280 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2281 let local_def_id = this.definitions.local_def_id(item.id);
2282 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2283 this.visit_generics(generics);
2284 walk_list!(this, visit_param_bound, bounds);
2286 for trait_item in trait_items {
2287 let type_parameters = HasTypeParameters(&trait_item.generics,
2288 TraitOrImplItemRibKind);
2289 this.with_type_parameter_rib(type_parameters, |this| {
2290 match trait_item.node {
2291 TraitItemKind::Const(ref ty, ref default) => {
2294 // Only impose the restrictions of
2295 // ConstRibKind for an actual constant
2296 // expression in a provided default.
2297 if let Some(ref expr) = *default{
2298 this.with_constant_rib(|this| {
2299 this.visit_expr(expr);
2303 TraitItemKind::Method(_, _) => {
2304 visit::walk_trait_item(this, trait_item)
2306 TraitItemKind::Type(..) => {
2307 visit::walk_trait_item(this, trait_item)
2309 TraitItemKind::Macro(_) => {
2310 panic!("unexpanded macro in resolve!")
2319 ItemKind::TraitAlias(ref generics, ref bounds) => {
2320 // Create a new rib for the trait-wide type parameters.
2321 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2322 let local_def_id = this.definitions.local_def_id(item.id);
2323 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2324 this.visit_generics(generics);
2325 walk_list!(this, visit_param_bound, bounds);
2330 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2331 self.with_scope(item.id, |this| {
2332 visit::walk_item(this, item);
2336 ItemKind::Static(ref ty, _, ref expr) |
2337 ItemKind::Const(ref ty, ref expr) => {
2338 self.with_item_rib(|this| {
2340 this.with_constant_rib(|this| {
2341 this.visit_expr(expr);
2346 ItemKind::Use(..) | ItemKind::ExternCrate(..) |
2347 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2348 // do nothing, these are just around to be encoded
2351 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2355 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2356 where F: FnOnce(&mut Resolver)
2358 match type_parameters {
2359 HasTypeParameters(generics, rib_kind) => {
2360 let mut function_type_rib = Rib::new(rib_kind);
2361 let mut seen_bindings = FxHashMap::default();
2362 for param in &generics.params {
2364 GenericParamKind::Lifetime { .. } => {}
2365 GenericParamKind::Type { .. } => {
2366 let ident = param.ident.modern();
2367 debug!("with_type_parameter_rib: {}", param.id);
2369 if seen_bindings.contains_key(&ident) {
2370 let span = seen_bindings.get(&ident).unwrap();
2371 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2375 resolve_error(self, param.ident.span, err);
2377 seen_bindings.entry(ident).or_insert(param.ident.span);
2379 // Plain insert (no renaming).
2380 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2381 function_type_rib.bindings.insert(ident, def);
2382 self.record_def(param.id, PathResolution::new(def));
2386 self.ribs[TypeNS].push(function_type_rib);
2389 NoTypeParameters => {
2396 if let HasTypeParameters(..) = type_parameters {
2397 self.ribs[TypeNS].pop();
2401 fn with_label_rib<F>(&mut self, f: F)
2402 where F: FnOnce(&mut Resolver)
2404 self.label_ribs.push(Rib::new(NormalRibKind));
2406 self.label_ribs.pop();
2409 fn with_item_rib<F>(&mut self, f: F)
2410 where F: FnOnce(&mut Resolver)
2412 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2413 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2415 self.ribs[TypeNS].pop();
2416 self.ribs[ValueNS].pop();
2419 fn with_constant_rib<F>(&mut self, f: F)
2420 where F: FnOnce(&mut Resolver)
2422 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2423 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2425 self.label_ribs.pop();
2426 self.ribs[ValueNS].pop();
2429 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2430 where F: FnOnce(&mut Resolver) -> T
2432 // Handle nested impls (inside fn bodies)
2433 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2434 let result = f(self);
2435 self.current_self_type = previous_value;
2439 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2440 where F: FnOnce(&mut Resolver) -> T
2442 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2443 let result = f(self);
2444 self.current_self_item = previous_value;
2448 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2449 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2450 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2452 let mut new_val = None;
2453 let mut new_id = None;
2454 if let Some(trait_ref) = opt_trait_ref {
2455 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2456 let def = self.smart_resolve_path_fragment(
2460 trait_ref.path.span,
2461 PathSource::Trait(AliasPossibility::No),
2462 CrateLint::SimplePath(trait_ref.ref_id),
2464 if def != Def::Err {
2465 new_id = Some(def.def_id());
2466 let span = trait_ref.path.span;
2467 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2468 self.resolve_path_without_parent_scope(
2474 CrateLint::SimplePath(trait_ref.ref_id),
2477 new_val = Some((module, trait_ref.clone()));
2481 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2482 let result = f(self, new_id);
2483 self.current_trait_ref = original_trait_ref;
2487 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2488 where F: FnOnce(&mut Resolver)
2490 let mut self_type_rib = Rib::new(NormalRibKind);
2492 // plain insert (no renaming, types are not currently hygienic....)
2493 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2494 self.ribs[TypeNS].push(self_type_rib);
2496 self.ribs[TypeNS].pop();
2499 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2500 where F: FnOnce(&mut Resolver)
2502 let self_def = Def::SelfCtor(impl_id);
2503 let mut self_type_rib = Rib::new(NormalRibKind);
2504 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2505 self.ribs[ValueNS].push(self_type_rib);
2507 self.ribs[ValueNS].pop();
2510 fn resolve_implementation(&mut self,
2511 generics: &Generics,
2512 opt_trait_reference: &Option<TraitRef>,
2515 impl_items: &[ImplItem]) {
2516 // If applicable, create a rib for the type parameters.
2517 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2518 // Dummy self type for better errors if `Self` is used in the trait path.
2519 this.with_self_rib(Def::SelfTy(None, None), |this| {
2520 // Resolve the trait reference, if necessary.
2521 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2522 let item_def_id = this.definitions.local_def_id(item_id);
2523 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2524 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2525 // Resolve type arguments in the trait path.
2526 visit::walk_trait_ref(this, trait_ref);
2528 // Resolve the self type.
2529 this.visit_ty(self_type);
2530 // Resolve the type parameters.
2531 this.visit_generics(generics);
2532 // Resolve the items within the impl.
2533 this.with_current_self_type(self_type, |this| {
2534 this.with_self_struct_ctor_rib(item_def_id, |this| {
2535 for impl_item in impl_items {
2536 this.resolve_visibility(&impl_item.vis);
2538 // We also need a new scope for the impl item type parameters.
2539 let type_parameters = HasTypeParameters(&impl_item.generics,
2540 TraitOrImplItemRibKind);
2541 this.with_type_parameter_rib(type_parameters, |this| {
2542 use self::ResolutionError::*;
2543 match impl_item.node {
2544 ImplItemKind::Const(..) => {
2545 // If this is a trait impl, ensure the const
2547 this.check_trait_item(impl_item.ident,
2550 |n, s| ConstNotMemberOfTrait(n, s));
2551 this.with_constant_rib(|this|
2552 visit::walk_impl_item(this, impl_item)
2555 ImplItemKind::Method(..) => {
2556 // If this is a trait impl, ensure the method
2558 this.check_trait_item(impl_item.ident,
2561 |n, s| MethodNotMemberOfTrait(n, s));
2563 visit::walk_impl_item(this, impl_item);
2565 ImplItemKind::Type(ref ty) => {
2566 // If this is a trait impl, ensure the type
2568 this.check_trait_item(impl_item.ident,
2571 |n, s| TypeNotMemberOfTrait(n, s));
2575 ImplItemKind::Existential(ref bounds) => {
2576 // If this is a trait impl, ensure the type
2578 this.check_trait_item(impl_item.ident,
2581 |n, s| TypeNotMemberOfTrait(n, s));
2583 for bound in bounds {
2584 this.visit_param_bound(bound);
2587 ImplItemKind::Macro(_) =>
2588 panic!("unexpanded macro in resolve!"),
2600 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2601 where F: FnOnce(Name, &str) -> ResolutionError
2603 // If there is a TraitRef in scope for an impl, then the method must be in the
2605 if let Some((module, _)) = self.current_trait_ref {
2606 if self.resolve_ident_in_module(
2607 ModuleOrUniformRoot::Module(module),
2613 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2614 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2619 fn resolve_local(&mut self, local: &Local) {
2620 // Resolve the type.
2621 walk_list!(self, visit_ty, &local.ty);
2623 // Resolve the initializer.
2624 walk_list!(self, visit_expr, &local.init);
2626 // Resolve the pattern.
2627 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2630 // build a map from pattern identifiers to binding-info's.
2631 // this is done hygienically. This could arise for a macro
2632 // that expands into an or-pattern where one 'x' was from the
2633 // user and one 'x' came from the macro.
2634 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2635 let mut binding_map = FxHashMap::default();
2637 pat.walk(&mut |pat| {
2638 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2639 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2640 Some(Def::Local(..)) => true,
2643 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2644 binding_map.insert(ident, binding_info);
2653 // check that all of the arms in an or-pattern have exactly the
2654 // same set of bindings, with the same binding modes for each.
2655 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2656 if pats.is_empty() {
2660 let mut missing_vars = FxHashMap::default();
2661 let mut inconsistent_vars = FxHashMap::default();
2662 for (i, p) in pats.iter().enumerate() {
2663 let map_i = self.binding_mode_map(&p);
2665 for (j, q) in pats.iter().enumerate() {
2670 let map_j = self.binding_mode_map(&q);
2671 for (&key, &binding_i) in &map_i {
2672 if map_j.is_empty() { // Account for missing bindings when
2673 let binding_error = missing_vars // map_j has none.
2675 .or_insert(BindingError {
2677 origin: BTreeSet::new(),
2678 target: BTreeSet::new(),
2680 binding_error.origin.insert(binding_i.span);
2681 binding_error.target.insert(q.span);
2683 for (&key_j, &binding_j) in &map_j {
2684 match map_i.get(&key_j) {
2685 None => { // missing binding
2686 let binding_error = missing_vars
2688 .or_insert(BindingError {
2690 origin: BTreeSet::new(),
2691 target: BTreeSet::new(),
2693 binding_error.origin.insert(binding_j.span);
2694 binding_error.target.insert(p.span);
2696 Some(binding_i) => { // check consistent binding
2697 if binding_i.binding_mode != binding_j.binding_mode {
2700 .or_insert((binding_j.span, binding_i.span));
2708 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2709 missing_vars.sort();
2710 for (_, v) in missing_vars {
2712 *v.origin.iter().next().unwrap(),
2713 ResolutionError::VariableNotBoundInPattern(v));
2715 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2716 inconsistent_vars.sort();
2717 for (name, v) in inconsistent_vars {
2718 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2722 fn resolve_arm(&mut self, arm: &Arm) {
2723 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2725 let mut bindings_list = FxHashMap::default();
2726 for pattern in &arm.pats {
2727 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2730 // This has to happen *after* we determine which pat_idents are variants
2731 self.check_consistent_bindings(&arm.pats);
2733 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2734 self.visit_expr(expr)
2736 self.visit_expr(&arm.body);
2738 self.ribs[ValueNS].pop();
2741 fn resolve_block(&mut self, block: &Block) {
2742 debug!("(resolving block) entering block");
2743 // Move down in the graph, if there's an anonymous module rooted here.
2744 let orig_module = self.current_module;
2745 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2747 let mut num_macro_definition_ribs = 0;
2748 if let Some(anonymous_module) = anonymous_module {
2749 debug!("(resolving block) found anonymous module, moving down");
2750 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2751 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2752 self.current_module = anonymous_module;
2753 self.finalize_current_module_macro_resolutions();
2755 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2758 // Descend into the block.
2759 for stmt in &block.stmts {
2760 if let ast::StmtKind::Item(ref item) = stmt.node {
2761 if let ast::ItemKind::MacroDef(..) = item.node {
2762 num_macro_definition_ribs += 1;
2763 let def = self.definitions.local_def_id(item.id);
2764 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2765 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2769 self.visit_stmt(stmt);
2773 self.current_module = orig_module;
2774 for _ in 0 .. num_macro_definition_ribs {
2775 self.ribs[ValueNS].pop();
2776 self.label_ribs.pop();
2778 self.ribs[ValueNS].pop();
2779 if anonymous_module.is_some() {
2780 self.ribs[TypeNS].pop();
2782 debug!("(resolving block) leaving block");
2785 fn fresh_binding(&mut self,
2788 outer_pat_id: NodeId,
2789 pat_src: PatternSource,
2790 bindings: &mut FxHashMap<Ident, NodeId>)
2792 // Add the binding to the local ribs, if it
2793 // doesn't already exist in the bindings map. (We
2794 // must not add it if it's in the bindings map
2795 // because that breaks the assumptions later
2796 // passes make about or-patterns.)
2797 let ident = ident.modern_and_legacy();
2798 let mut def = Def::Local(pat_id);
2799 match bindings.get(&ident).cloned() {
2800 Some(id) if id == outer_pat_id => {
2801 // `Variant(a, a)`, error
2805 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2809 Some(..) if pat_src == PatternSource::FnParam => {
2810 // `fn f(a: u8, a: u8)`, error
2814 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2818 Some(..) if pat_src == PatternSource::Match ||
2819 pat_src == PatternSource::IfLet ||
2820 pat_src == PatternSource::WhileLet => {
2821 // `Variant1(a) | Variant2(a)`, ok
2822 // Reuse definition from the first `a`.
2823 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2826 span_bug!(ident.span, "two bindings with the same name from \
2827 unexpected pattern source {:?}", pat_src);
2830 // A completely fresh binding, add to the lists if it's valid.
2831 if ident.name != keywords::Invalid.name() {
2832 bindings.insert(ident, outer_pat_id);
2833 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2838 PathResolution::new(def)
2841 fn resolve_pattern(&mut self,
2843 pat_src: PatternSource,
2844 // Maps idents to the node ID for the
2845 // outermost pattern that binds them.
2846 bindings: &mut FxHashMap<Ident, NodeId>) {
2847 // Visit all direct subpatterns of this pattern.
2848 let outer_pat_id = pat.id;
2849 pat.walk(&mut |pat| {
2851 PatKind::Ident(bmode, ident, ref opt_pat) => {
2852 // First try to resolve the identifier as some existing
2853 // entity, then fall back to a fresh binding.
2854 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2856 .and_then(LexicalScopeBinding::item);
2857 let resolution = binding.map(NameBinding::def).and_then(|def| {
2858 let is_syntactic_ambiguity = opt_pat.is_none() &&
2859 bmode == BindingMode::ByValue(Mutability::Immutable);
2861 Def::StructCtor(_, CtorKind::Const) |
2862 Def::VariantCtor(_, CtorKind::Const) |
2863 Def::Const(..) if is_syntactic_ambiguity => {
2864 // Disambiguate in favor of a unit struct/variant
2865 // or constant pattern.
2866 self.record_use(ident, ValueNS, binding.unwrap());
2867 Some(PathResolution::new(def))
2869 Def::StructCtor(..) | Def::VariantCtor(..) |
2870 Def::Const(..) | Def::Static(..) => {
2871 // This is unambiguously a fresh binding, either syntactically
2872 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2873 // to something unusable as a pattern (e.g. constructor function),
2874 // but we still conservatively report an error, see
2875 // issues/33118#issuecomment-233962221 for one reason why.
2879 ResolutionError::BindingShadowsSomethingUnacceptable(
2880 pat_src.descr(), ident.name, binding.unwrap())
2884 Def::Fn(..) | Def::Err => {
2885 // These entities are explicitly allowed
2886 // to be shadowed by fresh bindings.
2890 span_bug!(ident.span, "unexpected definition for an \
2891 identifier in pattern: {:?}", def);
2894 }).unwrap_or_else(|| {
2895 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2898 self.record_def(pat.id, resolution);
2901 PatKind::TupleStruct(ref path, ..) => {
2902 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2905 PatKind::Path(ref qself, ref path) => {
2906 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2909 PatKind::Struct(ref path, ..) => {
2910 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2918 visit::walk_pat(self, pat);
2921 // High-level and context dependent path resolution routine.
2922 // Resolves the path and records the resolution into definition map.
2923 // If resolution fails tries several techniques to find likely
2924 // resolution candidates, suggest imports or other help, and report
2925 // errors in user friendly way.
2926 fn smart_resolve_path(&mut self,
2928 qself: Option<&QSelf>,
2932 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2935 /// A variant of `smart_resolve_path` where you also specify extra
2936 /// information about where the path came from; this extra info is
2937 /// sometimes needed for the lint that recommends rewriting
2938 /// absolute paths to `crate`, so that it knows how to frame the
2939 /// suggestion. If you are just resolving a path like `foo::bar`
2940 /// that appears...somewhere, though, then you just want
2941 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2942 /// already provides.
2943 fn smart_resolve_path_with_crate_lint(
2946 qself: Option<&QSelf>,
2949 crate_lint: CrateLint
2950 ) -> PathResolution {
2951 self.smart_resolve_path_fragment(
2954 &Segment::from_path(path),
2961 fn smart_resolve_path_fragment(&mut self,
2963 qself: Option<&QSelf>,
2967 crate_lint: CrateLint)
2969 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
2970 let ns = source.namespace();
2971 let is_expected = &|def| source.is_expected(def);
2972 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2974 // Base error is amended with one short label and possibly some longer helps/notes.
2975 let report_errors = |this: &mut Self, def: Option<Def>| {
2976 // Make the base error.
2977 let expected = source.descr_expected();
2978 let path_str = Segment::names_to_string(path);
2979 let item_str = path.last().unwrap().ident;
2980 let code = source.error_code(def.is_some());
2981 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2982 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2983 format!("not a {}", expected),
2986 let item_span = path.last().unwrap().ident.span;
2987 let (mod_prefix, mod_str) = if path.len() == 1 {
2988 (String::new(), "this scope".to_string())
2989 } else if path.len() == 2 && path[0].ident.name == keywords::CrateRoot.name() {
2990 (String::new(), "the crate root".to_string())
2992 let mod_path = &path[..path.len() - 1];
2993 let mod_prefix = match this.resolve_path_without_parent_scope(
2994 None, mod_path, Some(TypeNS), false, span, CrateLint::No
2996 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
2999 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3000 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3002 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3003 format!("not found in {}", mod_str),
3006 let code = DiagnosticId::Error(code.into());
3007 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3009 // Emit help message for fake-self from other languages like `this`(javascript)
3010 if ["this", "my"].contains(&&*item_str.as_str())
3011 && this.self_value_is_available(path[0].ident.span, span) {
3012 err.span_suggestion_with_applicability(
3016 Applicability::MaybeIncorrect,
3020 // Emit special messages for unresolved `Self` and `self`.
3021 if is_self_type(path, ns) {
3022 __diagnostic_used!(E0411);
3023 err.code(DiagnosticId::Error("E0411".into()));
3024 let available_in = if this.session.features_untracked().self_in_typedefs {
3025 "impls, traits, and type definitions"
3029 err.span_label(span, format!("`Self` is only available in {}", available_in));
3030 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3031 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3034 return (err, Vec::new());
3036 if is_self_value(path, ns) {
3037 __diagnostic_used!(E0424);
3038 err.code(DiagnosticId::Error("E0424".into()));
3039 err.span_label(span, format!("`self` value is a keyword \
3041 methods with `self` parameter"));
3042 return (err, Vec::new());
3045 // Try to lookup the name in more relaxed fashion for better error reporting.
3046 let ident = path.last().unwrap().ident;
3047 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3048 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3049 let enum_candidates =
3050 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3051 let mut enum_candidates = enum_candidates.iter()
3052 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3053 enum_candidates.sort();
3054 for (sp, variant_path, enum_path) in enum_candidates {
3056 let msg = format!("there is an enum variant `{}`, \
3062 err.span_suggestion_with_applicability(
3064 "you can try using the variant's enum",
3066 Applicability::MachineApplicable,
3071 if path.len() == 1 && this.self_type_is_available(span) {
3072 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3073 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3075 AssocSuggestion::Field => {
3076 err.span_suggestion_with_applicability(
3079 format!("self.{}", path_str),
3080 Applicability::MachineApplicable,
3082 if !self_is_available {
3083 err.span_label(span, format!("`self` value is a keyword \
3085 methods with `self` parameter"));
3088 AssocSuggestion::MethodWithSelf if self_is_available => {
3089 err.span_suggestion_with_applicability(
3092 format!("self.{}", path_str),
3093 Applicability::MachineApplicable,
3096 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3097 err.span_suggestion_with_applicability(
3100 format!("Self::{}", path_str),
3101 Applicability::MachineApplicable,
3105 return (err, candidates);
3109 let mut levenshtein_worked = false;
3112 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3113 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3114 levenshtein_worked = true;
3117 // Try context dependent help if relaxed lookup didn't work.
3118 if let Some(def) = def {
3119 match (def, source) {
3120 (Def::Macro(..), _) => {
3121 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3122 return (err, candidates);
3124 (Def::TyAlias(..), PathSource::Trait(_)) => {
3125 err.span_label(span, "type aliases cannot be used as traits");
3126 if nightly_options::is_nightly_build() {
3127 err.note("did you mean to use a trait alias?");
3129 return (err, candidates);
3131 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3132 ExprKind::Field(_, ident) => {
3133 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3135 return (err, candidates);
3137 ExprKind::MethodCall(ref segment, ..) => {
3138 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3139 path_str, segment.ident));
3140 return (err, candidates);
3144 (Def::Enum(..), PathSource::TupleStruct)
3145 | (Def::Enum(..), PathSource::Expr(..)) => {
3146 if let Some(variants) = this.collect_enum_variants(def) {
3147 err.note(&format!("did you mean to use one \
3148 of the following variants?\n{}",
3150 .map(|suggestion| path_names_to_string(suggestion))
3151 .map(|suggestion| format!("- `{}`", suggestion))
3152 .collect::<Vec<_>>()
3156 err.note("did you mean to use one of the enum's variants?");
3158 return (err, candidates);
3160 (Def::Struct(def_id), _) if ns == ValueNS => {
3161 if let Some((ctor_def, ctor_vis))
3162 = this.struct_constructors.get(&def_id).cloned() {
3163 let accessible_ctor = this.is_accessible(ctor_vis);
3164 if is_expected(ctor_def) && !accessible_ctor {
3165 err.span_label(span, format!("constructor is not visible \
3166 here due to private fields"));
3169 // HACK(estebank): find a better way to figure out that this was a
3170 // parser issue where a struct literal is being used on an expression
3171 // where a brace being opened means a block is being started. Look
3172 // ahead for the next text to see if `span` is followed by a `{`.
3173 let sm = this.session.source_map();
3176 sp = sm.next_point(sp);
3177 match sm.span_to_snippet(sp) {
3178 Ok(ref snippet) => {
3179 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3186 let followed_by_brace = match sm.span_to_snippet(sp) {
3187 Ok(ref snippet) if snippet == "{" => true,
3191 PathSource::Expr(Some(parent)) => {
3193 ExprKind::MethodCall(ref path_assignment, _) => {
3194 err.span_suggestion_with_applicability(
3195 sm.start_point(parent.span)
3196 .to(path_assignment.ident.span),
3197 "use `::` to access an associated function",
3200 path_assignment.ident),
3201 Applicability::MaybeIncorrect
3203 return (err, candidates);
3208 format!("did you mean `{} {{ /* fields */ }}`?",
3211 return (err, candidates);
3215 PathSource::Expr(None) if followed_by_brace == true => {
3218 format!("did you mean `({} {{ /* fields */ }})`?",
3221 return (err, candidates);
3226 format!("did you mean `{} {{ /* fields */ }}`?",
3229 return (err, candidates);
3233 return (err, candidates);
3235 (Def::Union(..), _) |
3236 (Def::Variant(..), _) |
3237 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3238 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3240 return (err, candidates);
3242 (Def::SelfTy(..), _) if ns == ValueNS => {
3243 err.span_label(span, fallback_label);
3244 err.note("can't use `Self` as a constructor, you must use the \
3245 implemented struct");
3246 return (err, candidates);
3248 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3249 err.note("can't use a type alias as a constructor");
3250 return (err, candidates);
3257 if !levenshtein_worked {
3258 err.span_label(base_span, fallback_label);
3259 this.type_ascription_suggestion(&mut err, base_span);
3263 let report_errors = |this: &mut Self, def: Option<Def>| {
3264 let (err, candidates) = report_errors(this, def);
3265 let def_id = this.current_module.normal_ancestor_id;
3266 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3267 let better = def.is_some();
3268 this.use_injections.push(UseError { err, candidates, node_id, better });
3269 err_path_resolution()
3272 let resolution = match self.resolve_qpath_anywhere(
3278 source.defer_to_typeck(),
3279 source.global_by_default(),
3282 Some(resolution) if resolution.unresolved_segments() == 0 => {
3283 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3286 // Add a temporary hack to smooth the transition to new struct ctor
3287 // visibility rules. See #38932 for more details.
3289 if let Def::Struct(def_id) = resolution.base_def() {
3290 if let Some((ctor_def, ctor_vis))
3291 = self.struct_constructors.get(&def_id).cloned() {
3292 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3293 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3294 self.session.buffer_lint(lint, id, span,
3295 "private struct constructors are not usable through \
3296 re-exports in outer modules",
3298 res = Some(PathResolution::new(ctor_def));
3303 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3306 Some(resolution) if source.defer_to_typeck() => {
3307 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3308 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3309 // it needs to be added to the trait map.
3311 let item_name = path.last().unwrap().ident;
3312 let traits = self.get_traits_containing_item(item_name, ns);
3313 self.trait_map.insert(id, traits);
3317 _ => report_errors(self, None)
3320 if let PathSource::TraitItem(..) = source {} else {
3321 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3322 self.record_def(id, resolution);
3327 fn type_ascription_suggestion(&self,
3328 err: &mut DiagnosticBuilder,
3330 debug!("type_ascription_suggetion {:?}", base_span);
3331 let cm = self.session.source_map();
3332 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3333 if let Some(sp) = self.current_type_ascription.last() {
3335 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3336 sp = cm.next_point(sp);
3337 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3338 debug!("snippet {:?}", snippet);
3339 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3340 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3341 debug!("{:?} {:?}", line_sp, line_base_sp);
3343 err.span_label(base_span,
3344 "expecting a type here because of type ascription");
3345 if line_sp != line_base_sp {
3346 err.span_suggestion_short_with_applicability(
3348 "did you mean to use `;` here instead?",
3350 Applicability::MaybeIncorrect,
3354 } else if !snippet.trim().is_empty() {
3355 debug!("tried to find type ascription `:` token, couldn't find it");
3365 fn self_type_is_available(&mut self, span: Span) -> bool {
3366 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3367 TypeNS, None, span);
3368 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3371 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3372 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3373 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3374 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3377 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3378 fn resolve_qpath_anywhere(&mut self,
3380 qself: Option<&QSelf>,
3382 primary_ns: Namespace,
3384 defer_to_typeck: bool,
3385 global_by_default: bool,
3386 crate_lint: CrateLint)
3387 -> Option<PathResolution> {
3388 let mut fin_res = None;
3389 // FIXME: can't resolve paths in macro namespace yet, macros are
3390 // processed by the little special hack below.
3391 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3392 if i == 0 || ns != primary_ns {
3393 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3394 // If defer_to_typeck, then resolution > no resolution,
3395 // otherwise full resolution > partial resolution > no resolution.
3396 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3398 res => if fin_res.is_none() { fin_res = res },
3402 if primary_ns != MacroNS &&
3403 (self.macro_names.contains(&path[0].ident.modern()) ||
3404 self.builtin_macros.get(&path[0].ident.name).cloned()
3405 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3406 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3407 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3408 // Return some dummy definition, it's enough for error reporting.
3410 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3416 /// Handles paths that may refer to associated items.
3417 fn resolve_qpath(&mut self,
3419 qself: Option<&QSelf>,
3423 global_by_default: bool,
3424 crate_lint: CrateLint)
3425 -> Option<PathResolution> {
3427 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3428 ns={:?}, span={:?}, global_by_default={:?})",
3437 if let Some(qself) = qself {
3438 if qself.position == 0 {
3439 // This is a case like `<T>::B`, where there is no
3440 // trait to resolve. In that case, we leave the `B`
3441 // segment to be resolved by type-check.
3442 return Some(PathResolution::with_unresolved_segments(
3443 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3447 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3449 // Currently, `path` names the full item (`A::B::C`, in
3450 // our example). so we extract the prefix of that that is
3451 // the trait (the slice upto and including
3452 // `qself.position`). And then we recursively resolve that,
3453 // but with `qself` set to `None`.
3455 // However, setting `qself` to none (but not changing the
3456 // span) loses the information about where this path
3457 // *actually* appears, so for the purposes of the crate
3458 // lint we pass along information that this is the trait
3459 // name from a fully qualified path, and this also
3460 // contains the full span (the `CrateLint::QPathTrait`).
3461 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3462 let res = self.smart_resolve_path_fragment(
3465 &path[..qself.position + 1],
3467 PathSource::TraitItem(ns),
3468 CrateLint::QPathTrait {
3470 qpath_span: qself.path_span,
3474 // The remaining segments (the `C` in our example) will
3475 // have to be resolved by type-check, since that requires doing
3476 // trait resolution.
3477 return Some(PathResolution::with_unresolved_segments(
3478 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3482 let result = match self.resolve_path_without_parent_scope(
3490 PathResult::NonModule(path_res) => path_res,
3491 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3492 PathResolution::new(module.def().unwrap())
3494 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3495 // don't report an error right away, but try to fallback to a primitive type.
3496 // So, we are still able to successfully resolve something like
3498 // use std::u8; // bring module u8 in scope
3499 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3500 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3501 // // not to non-existent std::u8::max_value
3504 // Such behavior is required for backward compatibility.
3505 // The same fallback is used when `a` resolves to nothing.
3506 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3507 PathResult::Failed(..)
3508 if (ns == TypeNS || path.len() > 1) &&
3509 self.primitive_type_table.primitive_types
3510 .contains_key(&path[0].ident.name) => {
3511 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3512 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3514 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3515 PathResolution::new(module.def().unwrap()),
3516 PathResult::Failed(span, msg, false) => {
3517 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3518 err_path_resolution()
3520 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3521 PathResult::Failed(..) => return None,
3522 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3525 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3526 path[0].ident.name != keywords::CrateRoot.name() &&
3527 path[0].ident.name != keywords::DollarCrate.name() {
3528 let unqualified_result = {
3529 match self.resolve_path_without_parent_scope(
3531 &[*path.last().unwrap()],
3537 PathResult::NonModule(path_res) => path_res.base_def(),
3538 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3539 module.def().unwrap(),
3540 _ => return Some(result),
3543 if result.base_def() == unqualified_result {
3544 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3545 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3552 fn resolve_path_without_parent_scope(
3554 base_module: Option<ModuleOrUniformRoot<'a>>,
3556 opt_ns: Option<Namespace>, // `None` indicates a module path
3559 crate_lint: CrateLint,
3560 ) -> PathResult<'a> {
3561 // Macro and import paths must have full parent scope available during resolution,
3562 // other paths will do okay with parent module alone.
3563 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3564 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3565 self.resolve_path(base_module, path, opt_ns, &parent_scope,
3566 record_used, path_span, crate_lint)
3571 base_module: Option<ModuleOrUniformRoot<'a>>,
3573 opt_ns: Option<Namespace>, // `None` indicates a module path
3574 parent_scope: &ParentScope<'a>,
3577 crate_lint: CrateLint,
3578 ) -> PathResult<'a> {
3579 let mut module = base_module;
3580 let mut allow_super = true;
3581 let mut second_binding = None;
3582 self.current_module = parent_scope.module;
3585 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3586 path_span={:?}, crate_lint={:?})",
3594 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3595 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3596 let record_segment_def = |this: &mut Self, def| {
3598 if let Some(id) = id {
3599 if !this.def_map.contains_key(&id) {
3600 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3601 this.record_def(id, PathResolution::new(def));
3607 let is_last = i == path.len() - 1;
3608 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3609 let name = ident.name;
3611 allow_super &= ns == TypeNS &&
3612 (name == keywords::SelfValue.name() ||
3613 name == keywords::Super.name());
3616 if allow_super && name == keywords::Super.name() {
3617 let mut ctxt = ident.span.ctxt().modern();
3618 let self_module = match i {
3619 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3621 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3625 if let Some(self_module) = self_module {
3626 if let Some(parent) = self_module.parent {
3627 module = Some(ModuleOrUniformRoot::Module(
3628 self.resolve_self(&mut ctxt, parent)));
3632 let msg = "There are too many initial `super`s.".to_string();
3633 return PathResult::Failed(ident.span, msg, false);
3636 if name == keywords::SelfValue.name() {
3637 let mut ctxt = ident.span.ctxt().modern();
3638 module = Some(ModuleOrUniformRoot::Module(
3639 self.resolve_self(&mut ctxt, self.current_module)));
3642 if name == keywords::Extern.name() ||
3643 name == keywords::CrateRoot.name() &&
3644 self.session.rust_2018() {
3645 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3648 if name == keywords::CrateRoot.name() ||
3649 name == keywords::Crate.name() ||
3650 name == keywords::DollarCrate.name() {
3651 // `::a::b`, `crate::a::b` or `$crate::a::b`
3652 module = Some(ModuleOrUniformRoot::Module(
3653 self.resolve_crate_root(ident)));
3659 // Report special messages for path segment keywords in wrong positions.
3660 if ident.is_path_segment_keyword() && i != 0 {
3661 let name_str = if name == keywords::CrateRoot.name() {
3662 "crate root".to_string()
3664 format!("`{}`", name)
3666 let msg = if i == 1 && path[0].ident.name == keywords::CrateRoot.name() {
3667 format!("global paths cannot start with {}", name_str)
3669 format!("{} in paths can only be used in start position", name_str)
3671 return PathResult::Failed(ident.span, msg, false);
3674 let binding = if let Some(module) = module {
3675 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3676 } else if opt_ns == Some(MacroNS) {
3677 assert!(ns == TypeNS);
3678 self.early_resolve_ident_in_lexical_scope(ident, ns, None, parent_scope,
3679 record_used, record_used, path_span)
3681 let record_used_id =
3682 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3683 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3684 // we found a locally-imported or available item/module
3685 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3686 // we found a local variable or type param
3687 Some(LexicalScopeBinding::Def(def))
3688 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3689 record_segment_def(self, def);
3690 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3694 _ => Err(if record_used { Determined } else { Undetermined }),
3701 second_binding = Some(binding);
3703 let def = binding.def();
3704 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3705 if let Some(next_module) = binding.module() {
3706 module = Some(ModuleOrUniformRoot::Module(next_module));
3707 record_segment_def(self, def);
3708 } else if def == Def::ToolMod && i + 1 != path.len() {
3709 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3710 return PathResult::NonModule(PathResolution::new(def));
3711 } else if def == Def::Err {
3712 return PathResult::NonModule(err_path_resolution());
3713 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3714 self.lint_if_path_starts_with_module(
3720 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3721 def, path.len() - i - 1
3724 return PathResult::Failed(ident.span,
3725 format!("Not a module `{}`", ident),
3729 Err(Undetermined) => return PathResult::Indeterminate,
3730 Err(Determined) => {
3731 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3732 if opt_ns.is_some() && !module.is_normal() {
3733 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3734 module.def().unwrap(), path.len() - i
3738 let module_def = match module {
3739 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3742 let msg = if module_def == self.graph_root.def() {
3743 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3744 let mut candidates =
3745 self.lookup_import_candidates(name, TypeNS, is_mod);
3746 candidates.sort_by_cached_key(|c| {
3747 (c.path.segments.len(), c.path.to_string())
3749 if let Some(candidate) = candidates.get(0) {
3750 format!("Did you mean `{}`?", candidate.path)
3752 format!("Maybe a missing `extern crate {};`?", ident)
3755 format!("Use of undeclared type or module `{}`", ident)
3757 format!("Could not find `{}` in `{}`", ident, path[i - 1].ident)
3759 return PathResult::Failed(ident.span, msg, is_last);
3764 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3766 PathResult::Module(module.unwrap_or_else(|| {
3767 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3771 fn lint_if_path_starts_with_module(
3773 crate_lint: CrateLint,
3776 second_binding: Option<&NameBinding>,
3778 // In the 2018 edition this lint is a hard error, so nothing to do
3779 if self.session.rust_2018() {
3783 let (diag_id, diag_span) = match crate_lint {
3784 CrateLint::No => return,
3785 CrateLint::SimplePath(id) => (id, path_span),
3786 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3787 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3790 let first_name = match path.get(0) {
3791 Some(ident) => ident.ident.name,
3795 // We're only interested in `use` paths which should start with
3796 // `{{root}}` or `extern` currently.
3797 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3802 // If this import looks like `crate::...` it's already good
3803 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3804 // Otherwise go below to see if it's an extern crate
3806 // If the path has length one (and it's `CrateRoot` most likely)
3807 // then we don't know whether we're gonna be importing a crate or an
3808 // item in our crate. Defer this lint to elsewhere
3812 // If the first element of our path was actually resolved to an
3813 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3814 // warning, this looks all good!
3815 if let Some(binding) = second_binding {
3816 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3817 // Careful: we still want to rewrite paths from
3818 // renamed extern crates.
3819 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3825 let diag = lint::builtin::BuiltinLintDiagnostics
3826 ::AbsPathWithModule(diag_span);
3827 self.session.buffer_lint_with_diagnostic(
3828 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3830 "absolute paths must start with `self`, `super`, \
3831 `crate`, or an external crate name in the 2018 edition",
3835 // Resolve a local definition, potentially adjusting for closures.
3836 fn adjust_local_def(&mut self,
3841 span: Span) -> Def {
3842 let ribs = &self.ribs[ns][rib_index + 1..];
3844 // An invalid forward use of a type parameter from a previous default.
3845 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3847 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3849 assert_eq!(def, Def::Err);
3855 span_bug!(span, "unexpected {:?} in bindings", def)
3857 Def::Local(node_id) => {
3860 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3861 ForwardTyParamBanRibKind => {
3862 // Nothing to do. Continue.
3864 ClosureRibKind(function_id) => {
3867 let seen = self.freevars_seen
3870 if let Some(&index) = seen.get(&node_id) {
3871 def = Def::Upvar(node_id, index, function_id);
3874 let vec = self.freevars
3877 let depth = vec.len();
3878 def = Def::Upvar(node_id, depth, function_id);
3885 seen.insert(node_id, depth);
3888 ItemRibKind | TraitOrImplItemRibKind => {
3889 // This was an attempt to access an upvar inside a
3890 // named function item. This is not allowed, so we
3893 resolve_error(self, span,
3894 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3898 ConstantItemRibKind => {
3899 // Still doesn't deal with upvars
3901 resolve_error(self, span,
3902 ResolutionError::AttemptToUseNonConstantValueInConstant);
3909 Def::TyParam(..) | Def::SelfTy(..) => {
3912 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3913 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3914 ConstantItemRibKind => {
3915 // Nothing to do. Continue.
3918 // This was an attempt to use a type parameter outside
3921 resolve_error(self, span,
3922 ResolutionError::TypeParametersFromOuterFunction(def));
3934 fn lookup_assoc_candidate<FilterFn>(&mut self,
3937 filter_fn: FilterFn)
3938 -> Option<AssocSuggestion>
3939 where FilterFn: Fn(Def) -> bool
3941 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3943 TyKind::Path(None, _) => Some(t.id),
3944 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3945 // This doesn't handle the remaining `Ty` variants as they are not
3946 // that commonly the self_type, it might be interesting to provide
3947 // support for those in future.
3952 // Fields are generally expected in the same contexts as locals.
3953 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3954 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3955 // Look for a field with the same name in the current self_type.
3956 if let Some(resolution) = self.def_map.get(&node_id) {
3957 match resolution.base_def() {
3958 Def::Struct(did) | Def::Union(did)
3959 if resolution.unresolved_segments() == 0 => {
3960 if let Some(field_names) = self.field_names.get(&did) {
3961 if field_names.iter().any(|&field_name| ident.name == field_name) {
3962 return Some(AssocSuggestion::Field);
3972 // Look for associated items in the current trait.
3973 if let Some((module, _)) = self.current_trait_ref {
3974 if let Ok(binding) = self.resolve_ident_in_module(
3975 ModuleOrUniformRoot::Module(module),
3981 let def = binding.def();
3983 return Some(if self.has_self.contains(&def.def_id()) {
3984 AssocSuggestion::MethodWithSelf
3986 AssocSuggestion::AssocItem
3995 fn lookup_typo_candidate<FilterFn>(&mut self,
3998 filter_fn: FilterFn,
4001 where FilterFn: Fn(Def) -> bool
4003 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4004 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4005 if let Some(binding) = resolution.borrow().binding {
4006 if filter_fn(binding.def()) {
4007 names.push(ident.name);
4013 let mut names = Vec::new();
4014 if path.len() == 1 {
4015 // Search in lexical scope.
4016 // Walk backwards up the ribs in scope and collect candidates.
4017 for rib in self.ribs[ns].iter().rev() {
4018 // Locals and type parameters
4019 for (ident, def) in &rib.bindings {
4020 if filter_fn(*def) {
4021 names.push(ident.name);
4025 if let ModuleRibKind(module) = rib.kind {
4026 // Items from this module
4027 add_module_candidates(module, &mut names);
4029 if let ModuleKind::Block(..) = module.kind {
4030 // We can see through blocks
4032 // Items from the prelude
4033 if !module.no_implicit_prelude {
4034 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4035 if let Some(prelude) = self.prelude {
4036 add_module_candidates(prelude, &mut names);
4043 // Add primitive types to the mix
4044 if filter_fn(Def::PrimTy(Bool)) {
4046 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4050 // Search in module.
4051 let mod_path = &path[..path.len() - 1];
4052 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4053 None, mod_path, Some(TypeNS), false, span, CrateLint::No
4055 if let ModuleOrUniformRoot::Module(module) = module {
4056 add_module_candidates(module, &mut names);
4061 let name = path[path.len() - 1].ident.name;
4062 // Make sure error reporting is deterministic.
4063 names.sort_by_cached_key(|name| name.as_str());
4064 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4065 Some(found) if found != name => Some(found),
4070 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4071 where F: FnOnce(&mut Resolver)
4073 if let Some(label) = label {
4074 self.unused_labels.insert(id, label.ident.span);
4075 let def = Def::Label(id);
4076 self.with_label_rib(|this| {
4077 let ident = label.ident.modern_and_legacy();
4078 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4086 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4087 self.with_resolved_label(label, id, |this| this.visit_block(block));
4090 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4091 // First, record candidate traits for this expression if it could
4092 // result in the invocation of a method call.
4094 self.record_candidate_traits_for_expr_if_necessary(expr);
4096 // Next, resolve the node.
4098 ExprKind::Path(ref qself, ref path) => {
4099 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4100 visit::walk_expr(self, expr);
4103 ExprKind::Struct(ref path, ..) => {
4104 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4105 visit::walk_expr(self, expr);
4108 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4109 let def = self.search_label(label.ident, |rib, ident| {
4110 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4114 // Search again for close matches...
4115 // Picks the first label that is "close enough", which is not necessarily
4116 // the closest match
4117 let close_match = self.search_label(label.ident, |rib, ident| {
4118 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4119 find_best_match_for_name(names, &*ident.as_str(), None)
4121 self.record_def(expr.id, err_path_resolution());
4124 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4127 Some(Def::Label(id)) => {
4128 // Since this def is a label, it is never read.
4129 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4130 self.unused_labels.remove(&id);
4133 span_bug!(expr.span, "label wasn't mapped to a label def!");
4137 // visit `break` argument if any
4138 visit::walk_expr(self, expr);
4141 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4142 self.visit_expr(subexpression);
4144 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4145 let mut bindings_list = FxHashMap::default();
4147 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4149 // This has to happen *after* we determine which pat_idents are variants
4150 self.check_consistent_bindings(pats);
4151 self.visit_block(if_block);
4152 self.ribs[ValueNS].pop();
4154 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4157 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4159 ExprKind::While(ref subexpression, ref block, label) => {
4160 self.with_resolved_label(label, expr.id, |this| {
4161 this.visit_expr(subexpression);
4162 this.visit_block(block);
4166 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4167 self.with_resolved_label(label, expr.id, |this| {
4168 this.visit_expr(subexpression);
4169 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4170 let mut bindings_list = FxHashMap::default();
4172 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4174 // This has to happen *after* we determine which pat_idents are variants
4175 this.check_consistent_bindings(pats);
4176 this.visit_block(block);
4177 this.ribs[ValueNS].pop();
4181 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4182 self.visit_expr(subexpression);
4183 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4184 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4186 self.resolve_labeled_block(label, expr.id, block);
4188 self.ribs[ValueNS].pop();
4191 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4193 // Equivalent to `visit::walk_expr` + passing some context to children.
4194 ExprKind::Field(ref subexpression, _) => {
4195 self.resolve_expr(subexpression, Some(expr));
4197 ExprKind::MethodCall(ref segment, ref arguments) => {
4198 let mut arguments = arguments.iter();
4199 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4200 for argument in arguments {
4201 self.resolve_expr(argument, None);
4203 self.visit_path_segment(expr.span, segment);
4206 ExprKind::Call(ref callee, ref arguments) => {
4207 self.resolve_expr(callee, Some(expr));
4208 for argument in arguments {
4209 self.resolve_expr(argument, None);
4212 ExprKind::Type(ref type_expr, _) => {
4213 self.current_type_ascription.push(type_expr.span);
4214 visit::walk_expr(self, expr);
4215 self.current_type_ascription.pop();
4217 // Resolve the body of async exprs inside the async closure to which they desugar
4218 ExprKind::Async(_, async_closure_id, ref block) => {
4219 let rib_kind = ClosureRibKind(async_closure_id);
4220 self.ribs[ValueNS].push(Rib::new(rib_kind));
4221 self.label_ribs.push(Rib::new(rib_kind));
4222 self.visit_block(&block);
4223 self.label_ribs.pop();
4224 self.ribs[ValueNS].pop();
4226 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4227 // resolve the arguments within the proper scopes so that usages of them inside the
4228 // closure are detected as upvars rather than normal closure arg usages.
4230 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4231 ref fn_decl, ref body, _span,
4233 let rib_kind = ClosureRibKind(expr.id);
4234 self.ribs[ValueNS].push(Rib::new(rib_kind));
4235 self.label_ribs.push(Rib::new(rib_kind));
4236 // Resolve arguments:
4237 let mut bindings_list = FxHashMap::default();
4238 for argument in &fn_decl.inputs {
4239 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4240 self.visit_ty(&argument.ty);
4242 // No need to resolve return type-- the outer closure return type is
4243 // FunctionRetTy::Default
4245 // Now resolve the inner closure
4247 let rib_kind = ClosureRibKind(inner_closure_id);
4248 self.ribs[ValueNS].push(Rib::new(rib_kind));
4249 self.label_ribs.push(Rib::new(rib_kind));
4250 // No need to resolve arguments: the inner closure has none.
4251 // Resolve the return type:
4252 visit::walk_fn_ret_ty(self, &fn_decl.output);
4254 self.visit_expr(body);
4255 self.label_ribs.pop();
4256 self.ribs[ValueNS].pop();
4258 self.label_ribs.pop();
4259 self.ribs[ValueNS].pop();
4262 visit::walk_expr(self, expr);
4267 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4269 ExprKind::Field(_, ident) => {
4270 // FIXME(#6890): Even though you can't treat a method like a
4271 // field, we need to add any trait methods we find that match
4272 // the field name so that we can do some nice error reporting
4273 // later on in typeck.
4274 let traits = self.get_traits_containing_item(ident, ValueNS);
4275 self.trait_map.insert(expr.id, traits);
4277 ExprKind::MethodCall(ref segment, ..) => {
4278 debug!("(recording candidate traits for expr) recording traits for {}",
4280 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4281 self.trait_map.insert(expr.id, traits);
4289 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4290 -> Vec<TraitCandidate> {
4291 debug!("(getting traits containing item) looking for '{}'", ident.name);
4293 let mut found_traits = Vec::new();
4294 // Look for the current trait.
4295 if let Some((module, _)) = self.current_trait_ref {
4296 if self.resolve_ident_in_module(
4297 ModuleOrUniformRoot::Module(module),
4303 let def_id = module.def_id().unwrap();
4304 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4308 ident.span = ident.span.modern();
4309 let mut search_module = self.current_module;
4311 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4312 search_module = unwrap_or!(
4313 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4317 if let Some(prelude) = self.prelude {
4318 if !search_module.no_implicit_prelude {
4319 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4326 fn get_traits_in_module_containing_item(&mut self,
4330 found_traits: &mut Vec<TraitCandidate>) {
4331 assert!(ns == TypeNS || ns == ValueNS);
4332 let mut traits = module.traits.borrow_mut();
4333 if traits.is_none() {
4334 let mut collected_traits = Vec::new();
4335 module.for_each_child(|name, ns, binding| {
4336 if ns != TypeNS { return }
4337 if let Def::Trait(_) = binding.def() {
4338 collected_traits.push((name, binding));
4341 *traits = Some(collected_traits.into_boxed_slice());
4344 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4345 let module = binding.module().unwrap();
4346 let mut ident = ident;
4347 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4350 if self.resolve_ident_in_module_unadjusted(
4351 ModuleOrUniformRoot::Module(module),
4358 let import_id = match binding.kind {
4359 NameBindingKind::Import { directive, .. } => {
4360 self.maybe_unused_trait_imports.insert(directive.id);
4361 self.add_to_glob_map(directive.id, trait_name);
4366 let trait_def_id = module.def_id().unwrap();
4367 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4372 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4374 namespace: Namespace,
4375 start_module: &'a ModuleData<'a>,
4377 filter_fn: FilterFn)
4378 -> Vec<ImportSuggestion>
4379 where FilterFn: Fn(Def) -> bool
4381 let mut candidates = Vec::new();
4382 let mut seen_modules = FxHashSet::default();
4383 let not_local_module = crate_name != keywords::Crate.ident();
4384 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4386 while let Some((in_module,
4388 in_module_is_extern)) = worklist.pop() {
4389 self.populate_module_if_necessary(in_module);
4391 // We have to visit module children in deterministic order to avoid
4392 // instabilities in reported imports (#43552).
4393 in_module.for_each_child_stable(|ident, ns, name_binding| {
4394 // avoid imports entirely
4395 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4396 // avoid non-importable candidates as well
4397 if !name_binding.is_importable() { return; }
4399 // collect results based on the filter function
4400 if ident.name == lookup_name && ns == namespace {
4401 if filter_fn(name_binding.def()) {
4403 let mut segms = path_segments.clone();
4404 if self.session.rust_2018() {
4405 // crate-local absolute paths start with `crate::` in edition 2018
4406 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4408 0, ast::PathSegment::from_ident(crate_name)
4412 segms.push(ast::PathSegment::from_ident(ident));
4414 span: name_binding.span,
4417 // the entity is accessible in the following cases:
4418 // 1. if it's defined in the same crate, it's always
4419 // accessible (since private entities can be made public)
4420 // 2. if it's defined in another crate, it's accessible
4421 // only if both the module is public and the entity is
4422 // declared as public (due to pruning, we don't explore
4423 // outside crate private modules => no need to check this)
4424 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4425 candidates.push(ImportSuggestion { path: path });
4430 // collect submodules to explore
4431 if let Some(module) = name_binding.module() {
4433 let mut path_segments = path_segments.clone();
4434 path_segments.push(ast::PathSegment::from_ident(ident));
4436 let is_extern_crate_that_also_appears_in_prelude =
4437 name_binding.is_extern_crate() &&
4438 self.session.rust_2018();
4440 let is_visible_to_user =
4441 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4443 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4444 // add the module to the lookup
4445 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4446 if seen_modules.insert(module.def_id().unwrap()) {
4447 worklist.push((module, path_segments, is_extern));
4457 /// When name resolution fails, this method can be used to look up candidate
4458 /// entities with the expected name. It allows filtering them using the
4459 /// supplied predicate (which should be used to only accept the types of
4460 /// definitions expected e.g. traits). The lookup spans across all crates.
4462 /// NOTE: The method does not look into imports, but this is not a problem,
4463 /// since we report the definitions (thus, the de-aliased imports).
4464 fn lookup_import_candidates<FilterFn>(&mut self,
4466 namespace: Namespace,
4467 filter_fn: FilterFn)
4468 -> Vec<ImportSuggestion>
4469 where FilterFn: Fn(Def) -> bool
4471 let mut suggestions = self.lookup_import_candidates_from_module(
4472 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4474 if self.session.rust_2018() {
4475 let extern_prelude_names = self.extern_prelude.clone();
4476 for (ident, _) in extern_prelude_names.into_iter() {
4477 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4479 let crate_root = self.get_module(DefId {
4481 index: CRATE_DEF_INDEX,
4483 self.populate_module_if_necessary(&crate_root);
4485 suggestions.extend(self.lookup_import_candidates_from_module(
4486 lookup_name, namespace, crate_root, ident, &filter_fn));
4494 fn find_module(&mut self,
4496 -> Option<(Module<'a>, ImportSuggestion)>
4498 let mut result = None;
4499 let mut seen_modules = FxHashSet::default();
4500 let mut worklist = vec![(self.graph_root, Vec::new())];
4502 while let Some((in_module, path_segments)) = worklist.pop() {
4503 // abort if the module is already found
4504 if result.is_some() { break; }
4506 self.populate_module_if_necessary(in_module);
4508 in_module.for_each_child_stable(|ident, _, name_binding| {
4509 // abort if the module is already found or if name_binding is private external
4510 if result.is_some() || !name_binding.vis.is_visible_locally() {
4513 if let Some(module) = name_binding.module() {
4515 let mut path_segments = path_segments.clone();
4516 path_segments.push(ast::PathSegment::from_ident(ident));
4517 if module.def() == Some(module_def) {
4519 span: name_binding.span,
4520 segments: path_segments,
4522 result = Some((module, ImportSuggestion { path: path }));
4524 // add the module to the lookup
4525 if seen_modules.insert(module.def_id().unwrap()) {
4526 worklist.push((module, path_segments));
4536 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4537 if let Def::Enum(..) = enum_def {} else {
4538 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4541 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4542 self.populate_module_if_necessary(enum_module);
4544 let mut variants = Vec::new();
4545 enum_module.for_each_child_stable(|ident, _, name_binding| {
4546 if let Def::Variant(..) = name_binding.def() {
4547 let mut segms = enum_import_suggestion.path.segments.clone();
4548 segms.push(ast::PathSegment::from_ident(ident));
4549 variants.push(Path {
4550 span: name_binding.span,
4559 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4560 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4561 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4562 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4566 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4568 ast::VisibilityKind::Public => ty::Visibility::Public,
4569 ast::VisibilityKind::Crate(..) => {
4570 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4572 ast::VisibilityKind::Inherited => {
4573 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4575 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4576 // Visibilities are resolved as global by default, add starting root segment.
4577 let segments = path.make_root().iter().chain(path.segments.iter())
4578 .map(|seg| Segment { ident: seg.ident, id: Some(seg.id) })
4579 .collect::<Vec<_>>();
4580 let def = self.smart_resolve_path_fragment(
4585 PathSource::Visibility,
4586 CrateLint::SimplePath(id),
4588 if def == Def::Err {
4589 ty::Visibility::Public
4591 let vis = ty::Visibility::Restricted(def.def_id());
4592 if self.is_accessible(vis) {
4595 self.session.span_err(path.span, "visibilities can only be restricted \
4596 to ancestor modules");
4597 ty::Visibility::Public
4604 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4605 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4608 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4609 vis.is_accessible_from(module.normal_ancestor_id, self)
4612 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4613 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4614 if !ptr::eq(module, old_module) {
4615 span_bug!(binding.span, "parent module is reset for binding");
4620 fn disambiguate_legacy_vs_modern(
4622 legacy: &'a NameBinding<'a>,
4623 modern: &'a NameBinding<'a>,
4625 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4626 // is disambiguated to mitigate regressions from macro modularization.
4627 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4628 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4629 self.binding_parent_modules.get(&PtrKey(modern))) {
4630 (Some(legacy), Some(modern)) =>
4631 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4632 modern.is_ancestor_of(legacy),
4637 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4638 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4640 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4642 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4643 let note = if b1.expansion != Mark::root() {
4644 Some(if let Def::Macro(..) = b1.def() {
4645 format!("macro-expanded {} do not shadow",
4646 if b1.is_import() { "macro imports" } else { "macros" })
4648 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4649 if b1.is_import() { "imports" } else { "items" })
4651 } else if b1.is_glob_import() {
4652 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4657 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4658 err.span_label(ident.span, "ambiguous name");
4659 err.span_note(b1.span, &msg1);
4661 Def::Macro(..) if b2.span.is_dummy() =>
4662 err.note(&format!("`{}` is also a builtin macro", ident)),
4663 _ => err.span_note(b2.span, &msg2),
4665 if let Some(note) = note {
4671 fn report_errors(&mut self, krate: &Crate) {
4672 self.report_with_use_injections(krate);
4673 let mut reported_spans = FxHashSet::default();
4675 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4676 let msg = "macro-expanded `macro_export` macros from the current crate \
4677 cannot be referred to by absolute paths";
4678 self.session.buffer_lint_with_diagnostic(
4679 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4680 CRATE_NODE_ID, span_use, msg,
4681 lint::builtin::BuiltinLintDiagnostics::
4682 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4686 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4687 if reported_spans.insert(ident.span) {
4688 self.report_ambiguity_error(ident, b1, b2);
4692 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4693 if reported_spans.insert(dedup_span) {
4694 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4695 binding.descr(), ident.name);
4700 fn report_with_use_injections(&mut self, krate: &Crate) {
4701 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4702 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4703 if !candidates.is_empty() {
4704 show_candidates(&mut err, span, &candidates, better, found_use);
4710 fn report_conflict<'b>(&mut self,
4714 new_binding: &NameBinding<'b>,
4715 old_binding: &NameBinding<'b>) {
4716 // Error on the second of two conflicting names
4717 if old_binding.span.lo() > new_binding.span.lo() {
4718 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4721 let container = match parent.kind {
4722 ModuleKind::Def(Def::Mod(_), _) => "module",
4723 ModuleKind::Def(Def::Trait(_), _) => "trait",
4724 ModuleKind::Block(..) => "block",
4728 let old_noun = match old_binding.is_import() {
4730 false => "definition",
4733 let new_participle = match new_binding.is_import() {
4738 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4740 if let Some(s) = self.name_already_seen.get(&name) {
4746 let old_kind = match (ns, old_binding.module()) {
4747 (ValueNS, _) => "value",
4748 (MacroNS, _) => "macro",
4749 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4750 (TypeNS, Some(module)) if module.is_normal() => "module",
4751 (TypeNS, Some(module)) if module.is_trait() => "trait",
4752 (TypeNS, _) => "type",
4755 let msg = format!("the name `{}` is defined multiple times", name);
4757 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4758 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4759 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4760 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4761 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4763 _ => match (old_binding.is_import(), new_binding.is_import()) {
4764 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4765 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4766 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4770 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4775 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4776 if !old_binding.span.is_dummy() {
4777 err.span_label(self.session.source_map().def_span(old_binding.span),
4778 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4781 // See https://github.com/rust-lang/rust/issues/32354
4782 if old_binding.is_import() || new_binding.is_import() {
4783 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4789 let cm = self.session.source_map();
4790 let rename_msg = "you can use `as` to change the binding name of the import";
4794 NameBindingKind::Import { directive, ..},
4797 cm.span_to_snippet(binding.span),
4798 binding.kind.clone(),
4799 binding.span.is_dummy(),
4801 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4802 format!("Other{}", name)
4804 format!("other_{}", name)
4807 err.span_suggestion_with_applicability(
4810 match (&directive.subclass, snippet.as_ref()) {
4811 (ImportDirectiveSubclass::SingleImport { .. }, "self") =>
4812 format!("self as {}", suggested_name),
4813 (ImportDirectiveSubclass::SingleImport { source, .. }, _) =>
4816 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
4818 if snippet.ends_with(";") {
4824 (ImportDirectiveSubclass::ExternCrate { source, target, .. }, _) =>
4826 "extern crate {} as {};",
4827 source.unwrap_or(target.name),
4830 (_, _) => unreachable!(),
4832 Applicability::MaybeIncorrect,
4835 err.span_label(binding.span, rename_msg);
4840 self.name_already_seen.insert(name, span);
4843 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool, skip_feature_gate: bool)
4844 -> Option<&'a NameBinding<'a>> {
4845 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
4846 if let Some(binding) = entry.extern_crate_item {
4847 if !speculative && !skip_feature_gate && entry.introduced_by_item &&
4848 !self.session.features_untracked().extern_crate_item_prelude {
4849 emit_feature_err(&self.session.parse_sess, "extern_crate_item_prelude",
4850 ident.span, GateIssue::Language,
4851 "use of extern prelude names introduced \
4852 with `extern crate` items is unstable");
4856 let crate_id = if !speculative {
4857 self.crate_loader.process_path_extern(ident.name, ident.span)
4858 } else if let Some(crate_id) =
4859 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
4864 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
4865 self.populate_module_if_necessary(&crate_root);
4866 Some((crate_root, ty::Visibility::Public, ident.span, Mark::root())
4867 .to_name_binding(self.arenas))
4873 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
4874 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfType.name()
4877 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
4878 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfValue.name()
4881 fn names_to_string(idents: &[Ident]) -> String {
4882 let mut result = String::new();
4883 for (i, ident) in idents.iter()
4884 .filter(|ident| ident.name != keywords::CrateRoot.name())
4887 result.push_str("::");
4889 result.push_str(&ident.as_str());
4894 fn path_names_to_string(path: &Path) -> String {
4895 names_to_string(&path.segments.iter()
4896 .map(|seg| seg.ident)
4897 .collect::<Vec<_>>())
4900 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4901 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4902 let variant_path = &suggestion.path;
4903 let variant_path_string = path_names_to_string(variant_path);
4905 let path_len = suggestion.path.segments.len();
4906 let enum_path = ast::Path {
4907 span: suggestion.path.span,
4908 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4910 let enum_path_string = path_names_to_string(&enum_path);
4912 (suggestion.path.span, variant_path_string, enum_path_string)
4916 /// When an entity with a given name is not available in scope, we search for
4917 /// entities with that name in all crates. This method allows outputting the
4918 /// results of this search in a programmer-friendly way
4919 fn show_candidates(err: &mut DiagnosticBuilder,
4920 // This is `None` if all placement locations are inside expansions
4922 candidates: &[ImportSuggestion],
4926 // we want consistent results across executions, but candidates are produced
4927 // by iterating through a hash map, so make sure they are ordered:
4928 let mut path_strings: Vec<_> =
4929 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4930 path_strings.sort();
4932 let better = if better { "better " } else { "" };
4933 let msg_diff = match path_strings.len() {
4934 1 => " is found in another module, you can import it",
4935 _ => "s are found in other modules, you can import them",
4937 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4939 if let Some(span) = span {
4940 for candidate in &mut path_strings {
4941 // produce an additional newline to separate the new use statement
4942 // from the directly following item.
4943 let additional_newline = if found_use {
4948 *candidate = format!("use {};\n{}", candidate, additional_newline);
4951 err.span_suggestions_with_applicability(
4954 path_strings.into_iter(),
4955 Applicability::Unspecified,
4960 for candidate in path_strings {
4962 msg.push_str(&candidate);
4967 /// A somewhat inefficient routine to obtain the name of a module.
4968 fn module_to_string(module: Module) -> Option<String> {
4969 let mut names = Vec::new();
4971 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4972 if let ModuleKind::Def(_, name) = module.kind {
4973 if let Some(parent) = module.parent {
4974 names.push(Ident::with_empty_ctxt(name));
4975 collect_mod(names, parent);
4978 // danger, shouldn't be ident?
4979 names.push(Ident::from_str("<opaque>"));
4980 collect_mod(names, module.parent.unwrap());
4983 collect_mod(&mut names, module);
4985 if names.is_empty() {
4988 Some(names_to_string(&names.into_iter()
4990 .collect::<Vec<_>>()))
4993 fn err_path_resolution() -> PathResolution {
4994 PathResolution::new(Def::Err)
4997 #[derive(PartialEq,Copy, Clone)]
4998 pub enum MakeGlobMap {
5003 #[derive(Copy, Clone, Debug)]
5005 /// Do not issue the lint
5008 /// This lint applies to some random path like `impl ::foo::Bar`
5009 /// or whatever. In this case, we can take the span of that path.
5012 /// This lint comes from a `use` statement. In this case, what we
5013 /// care about really is the *root* `use` statement; e.g., if we
5014 /// have nested things like `use a::{b, c}`, we care about the
5016 UsePath { root_id: NodeId, root_span: Span },
5018 /// This is the "trait item" from a fully qualified path. For example,
5019 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5020 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5021 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5025 fn node_id(&self) -> Option<NodeId> {
5027 CrateLint::No => None,
5028 CrateLint::SimplePath(id) |
5029 CrateLint::UsePath { root_id: id, .. } |
5030 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5035 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }