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)`
485 // Path in `use a::b::{...};`
489 impl<'a> PathSource<'a> {
490 fn namespace(self) -> Namespace {
492 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
493 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
494 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
495 PathSource::TraitItem(ns) => ns,
499 fn global_by_default(self) -> bool {
501 PathSource::Visibility | PathSource::ImportPrefix => true,
502 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
503 PathSource::Struct | PathSource::TupleStruct |
504 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
508 fn defer_to_typeck(self) -> bool {
510 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
511 PathSource::Struct | PathSource::TupleStruct => true,
512 PathSource::Trait(_) | PathSource::TraitItem(..) |
513 PathSource::Visibility | PathSource::ImportPrefix => false,
517 fn descr_expected(self) -> &'static str {
519 PathSource::Type => "type",
520 PathSource::Trait(_) => "trait",
521 PathSource::Pat => "unit struct/variant or constant",
522 PathSource::Struct => "struct, variant or union type",
523 PathSource::TupleStruct => "tuple struct/variant",
524 PathSource::Visibility => "module",
525 PathSource::ImportPrefix => "module or enum",
526 PathSource::TraitItem(ns) => match ns {
527 TypeNS => "associated type",
528 ValueNS => "method or associated constant",
529 MacroNS => bug!("associated macro"),
531 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
532 // "function" here means "anything callable" rather than `Def::Fn`,
533 // this is not precise but usually more helpful than just "value".
534 Some(&ExprKind::Call(..)) => "function",
540 fn is_expected(self, def: Def) -> bool {
542 PathSource::Type => match def {
543 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
544 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
545 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
546 Def::Existential(..) |
547 Def::ForeignTy(..) => true,
550 PathSource::Trait(AliasPossibility::No) => match def {
551 Def::Trait(..) => true,
554 PathSource::Trait(AliasPossibility::Maybe) => match def {
555 Def::Trait(..) => true,
556 Def::TraitAlias(..) => true,
559 PathSource::Expr(..) => match def {
560 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
561 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
562 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
563 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
564 Def::SelfCtor(..) => true,
567 PathSource::Pat => match def {
568 Def::StructCtor(_, CtorKind::Const) |
569 Def::VariantCtor(_, CtorKind::Const) |
570 Def::Const(..) | Def::AssociatedConst(..) |
571 Def::SelfCtor(..) => true,
574 PathSource::TupleStruct => match def {
575 Def::StructCtor(_, CtorKind::Fn) |
576 Def::VariantCtor(_, CtorKind::Fn) |
577 Def::SelfCtor(..) => true,
580 PathSource::Struct => match def {
581 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
582 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
585 PathSource::TraitItem(ns) => match def {
586 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
587 Def::AssociatedTy(..) if ns == TypeNS => true,
590 PathSource::ImportPrefix => match def {
591 Def::Mod(..) | Def::Enum(..) => true,
594 PathSource::Visibility => match def {
595 Def::Mod(..) => true,
601 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
602 __diagnostic_used!(E0404);
603 __diagnostic_used!(E0405);
604 __diagnostic_used!(E0412);
605 __diagnostic_used!(E0422);
606 __diagnostic_used!(E0423);
607 __diagnostic_used!(E0425);
608 __diagnostic_used!(E0531);
609 __diagnostic_used!(E0532);
610 __diagnostic_used!(E0573);
611 __diagnostic_used!(E0574);
612 __diagnostic_used!(E0575);
613 __diagnostic_used!(E0576);
614 __diagnostic_used!(E0577);
615 __diagnostic_used!(E0578);
616 match (self, has_unexpected_resolution) {
617 (PathSource::Trait(_), true) => "E0404",
618 (PathSource::Trait(_), false) => "E0405",
619 (PathSource::Type, true) => "E0573",
620 (PathSource::Type, false) => "E0412",
621 (PathSource::Struct, true) => "E0574",
622 (PathSource::Struct, false) => "E0422",
623 (PathSource::Expr(..), true) => "E0423",
624 (PathSource::Expr(..), false) => "E0425",
625 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
626 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
627 (PathSource::TraitItem(..), true) => "E0575",
628 (PathSource::TraitItem(..), false) => "E0576",
629 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
630 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
635 struct UsePlacementFinder {
636 target_module: NodeId,
641 impl UsePlacementFinder {
642 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
643 let mut finder = UsePlacementFinder {
648 visit::walk_crate(&mut finder, krate);
649 (finder.span, finder.found_use)
653 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
656 module: &'tcx ast::Mod,
658 _: &[ast::Attribute],
661 if self.span.is_some() {
664 if node_id != self.target_module {
665 visit::walk_mod(self, module);
668 // find a use statement
669 for item in &module.items {
671 ItemKind::Use(..) => {
672 // don't suggest placing a use before the prelude
673 // import or other generated ones
674 if item.span.ctxt().outer().expn_info().is_none() {
675 self.span = Some(item.span.shrink_to_lo());
676 self.found_use = true;
680 // don't place use before extern crate
681 ItemKind::ExternCrate(_) => {}
682 // but place them before the first other item
683 _ => if self.span.map_or(true, |span| item.span < span ) {
684 if item.span.ctxt().outer().expn_info().is_none() {
685 // don't insert between attributes and an item
686 if item.attrs.is_empty() {
687 self.span = Some(item.span.shrink_to_lo());
689 // find the first attribute on the item
690 for attr in &item.attrs {
691 if self.span.map_or(true, |span| attr.span < span) {
692 self.span = Some(attr.span.shrink_to_lo());
703 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
704 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
705 fn visit_item(&mut self, item: &'tcx Item) {
706 self.resolve_item(item);
708 fn visit_arm(&mut self, arm: &'tcx Arm) {
709 self.resolve_arm(arm);
711 fn visit_block(&mut self, block: &'tcx Block) {
712 self.resolve_block(block);
714 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
715 self.with_constant_rib(|this| {
716 visit::walk_anon_const(this, constant);
719 fn visit_expr(&mut self, expr: &'tcx Expr) {
720 self.resolve_expr(expr, None);
722 fn visit_local(&mut self, local: &'tcx Local) {
723 self.resolve_local(local);
725 fn visit_ty(&mut self, ty: &'tcx Ty) {
727 TyKind::Path(ref qself, ref path) => {
728 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
730 TyKind::ImplicitSelf => {
731 let self_ty = keywords::SelfType.ident();
732 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
733 .map_or(Def::Err, |d| d.def());
734 self.record_def(ty.id, PathResolution::new(def));
738 visit::walk_ty(self, ty);
740 fn visit_poly_trait_ref(&mut self,
741 tref: &'tcx ast::PolyTraitRef,
742 m: &'tcx ast::TraitBoundModifier) {
743 self.smart_resolve_path(tref.trait_ref.ref_id, None,
744 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
745 visit::walk_poly_trait_ref(self, tref, m);
747 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
748 let type_parameters = match foreign_item.node {
749 ForeignItemKind::Fn(_, ref generics) => {
750 HasTypeParameters(generics, ItemRibKind)
752 ForeignItemKind::Static(..) => NoTypeParameters,
753 ForeignItemKind::Ty => NoTypeParameters,
754 ForeignItemKind::Macro(..) => NoTypeParameters,
756 self.with_type_parameter_rib(type_parameters, |this| {
757 visit::walk_foreign_item(this, foreign_item);
760 fn visit_fn(&mut self,
761 function_kind: FnKind<'tcx>,
762 declaration: &'tcx FnDecl,
766 let (rib_kind, asyncness) = match function_kind {
767 FnKind::ItemFn(_, ref header, ..) =>
768 (ItemRibKind, header.asyncness),
769 FnKind::Method(_, ref sig, _, _) =>
770 (TraitOrImplItemRibKind, sig.header.asyncness),
771 FnKind::Closure(_) =>
772 // Async closures aren't resolved through `visit_fn`-- they're
773 // processed separately
774 (ClosureRibKind(node_id), IsAsync::NotAsync),
777 // Create a value rib for the function.
778 self.ribs[ValueNS].push(Rib::new(rib_kind));
780 // Create a label rib for the function.
781 self.label_ribs.push(Rib::new(rib_kind));
783 // Add each argument to the rib.
784 let mut bindings_list = FxHashMap::default();
785 for argument in &declaration.inputs {
786 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
788 self.visit_ty(&argument.ty);
790 debug!("(resolving function) recorded argument");
792 visit::walk_fn_ret_ty(self, &declaration.output);
794 // Resolve the function body, potentially inside the body of an async closure
795 if let IsAsync::Async { closure_id, .. } = asyncness {
796 let rib_kind = ClosureRibKind(closure_id);
797 self.ribs[ValueNS].push(Rib::new(rib_kind));
798 self.label_ribs.push(Rib::new(rib_kind));
801 match function_kind {
802 FnKind::ItemFn(.., body) |
803 FnKind::Method(.., body) => {
804 self.visit_block(body);
806 FnKind::Closure(body) => {
807 self.visit_expr(body);
811 // Leave the body of the async closure
812 if asyncness.is_async() {
813 self.label_ribs.pop();
814 self.ribs[ValueNS].pop();
817 debug!("(resolving function) leaving function");
819 self.label_ribs.pop();
820 self.ribs[ValueNS].pop();
822 fn visit_generics(&mut self, generics: &'tcx Generics) {
823 // For type parameter defaults, we have to ban access
824 // to following type parameters, as the Substs can only
825 // provide previous type parameters as they're built. We
826 // put all the parameters on the ban list and then remove
827 // them one by one as they are processed and become available.
828 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
829 let mut found_default = false;
830 default_ban_rib.bindings.extend(generics.params.iter()
831 .filter_map(|param| match param.kind {
832 GenericParamKind::Lifetime { .. } => None,
833 GenericParamKind::Type { ref default, .. } => {
834 found_default |= default.is_some();
836 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
843 for param in &generics.params {
845 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
846 GenericParamKind::Type { ref default, .. } => {
847 for bound in ¶m.bounds {
848 self.visit_param_bound(bound);
851 if let Some(ref ty) = default {
852 self.ribs[TypeNS].push(default_ban_rib);
854 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
857 // Allow all following defaults to refer to this type parameter.
858 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
862 for p in &generics.where_clause.predicates {
863 self.visit_where_predicate(p);
868 #[derive(Copy, Clone)]
869 enum TypeParameters<'a, 'b> {
871 HasTypeParameters(// Type parameters.
874 // The kind of the rib used for type parameters.
878 /// The rib kind controls the translation of local
879 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
880 #[derive(Copy, Clone, Debug)]
882 /// No translation needs to be applied.
885 /// We passed through a closure scope at the given node ID.
886 /// Translate upvars as appropriate.
887 ClosureRibKind(NodeId /* func id */),
889 /// We passed through an impl or trait and are now in one of its
890 /// methods or associated types. Allow references to ty params that impl or trait
891 /// binds. Disallow any other upvars (including other ty params that are
893 TraitOrImplItemRibKind,
895 /// We passed through an item scope. Disallow upvars.
898 /// We're in a constant item. Can't refer to dynamic stuff.
901 /// We passed through a module.
902 ModuleRibKind(Module<'a>),
904 /// We passed through a `macro_rules!` statement
905 MacroDefinition(DefId),
907 /// All bindings in this rib are type parameters that can't be used
908 /// from the default of a type parameter because they're not declared
909 /// before said type parameter. Also see the `visit_generics` override.
910 ForwardTyParamBanRibKind,
915 /// A rib represents a scope names can live in. Note that these appear in many places, not just
916 /// around braces. At any place where the list of accessible names (of the given namespace)
917 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
918 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
921 /// Different [rib kinds](enum.RibKind) are transparent for different names.
923 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
924 /// resolving, the name is looked up from inside out.
927 bindings: FxHashMap<Ident, Def>,
932 fn new(kind: RibKind<'a>) -> Rib<'a> {
934 bindings: Default::default(),
940 /// An intermediate resolution result.
942 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
943 /// items are visible in their whole block, while defs only from the place they are defined
945 enum LexicalScopeBinding<'a> {
946 Item(&'a NameBinding<'a>),
950 impl<'a> LexicalScopeBinding<'a> {
951 fn item(self) -> Option<&'a NameBinding<'a>> {
953 LexicalScopeBinding::Item(binding) => Some(binding),
958 fn def(self) -> Def {
960 LexicalScopeBinding::Item(binding) => binding.def(),
961 LexicalScopeBinding::Def(def) => def,
966 #[derive(Copy, Clone, Debug)]
967 pub enum ModuleOrUniformRoot<'a> {
971 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
972 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
973 /// but *not* `extern`), in the Rust 2018 edition.
977 #[derive(Clone, Debug)]
978 enum PathResult<'a> {
979 Module(ModuleOrUniformRoot<'a>),
980 NonModule(PathResolution),
982 Failed(Span, String, bool /* is the error from the last segment? */),
986 /// An anonymous module, eg. just a block.
991 /// { // This is an anonymous module
992 /// f(); // This resolves to (2) as we are inside the block.
995 /// f(); // Resolves to (1)
999 /// Any module with a name.
1003 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1004 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1009 /// One node in the tree of modules.
1010 pub struct ModuleData<'a> {
1011 parent: Option<Module<'a>>,
1014 // The def id of the closest normal module (`mod`) ancestor (including this module).
1015 normal_ancestor_id: DefId,
1017 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1018 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1019 Option<&'a NameBinding<'a>>)>>,
1020 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1021 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1023 // Macro invocations that can expand into items in this module.
1024 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1026 no_implicit_prelude: bool,
1028 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1029 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1031 // Used to memoize the traits in this module for faster searches through all traits in scope.
1032 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1034 // Whether this module is populated. If not populated, any attempt to
1035 // access the children must be preceded with a
1036 // `populate_module_if_necessary` call.
1037 populated: Cell<bool>,
1039 /// Span of the module itself. Used for error reporting.
1045 type Module<'a> = &'a ModuleData<'a>;
1047 impl<'a> ModuleData<'a> {
1048 fn new(parent: Option<Module<'a>>,
1050 normal_ancestor_id: DefId,
1052 span: Span) -> Self {
1057 resolutions: Default::default(),
1058 legacy_macro_resolutions: RefCell::new(Vec::new()),
1059 macro_resolutions: RefCell::new(Vec::new()),
1060 builtin_attrs: RefCell::new(Vec::new()),
1061 unresolved_invocations: Default::default(),
1062 no_implicit_prelude: false,
1063 glob_importers: RefCell::new(Vec::new()),
1064 globs: RefCell::new(Vec::new()),
1065 traits: RefCell::new(None),
1066 populated: Cell::new(normal_ancestor_id.is_local()),
1072 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1073 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1074 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1078 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1079 let resolutions = self.resolutions.borrow();
1080 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1081 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1082 for &(&(ident, ns), &resolution) in resolutions.iter() {
1083 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1087 fn def(&self) -> Option<Def> {
1089 ModuleKind::Def(def, _) => Some(def),
1094 fn def_id(&self) -> Option<DefId> {
1095 self.def().as_ref().map(Def::def_id)
1098 // `self` resolves to the first module ancestor that `is_normal`.
1099 fn is_normal(&self) -> bool {
1101 ModuleKind::Def(Def::Mod(_), _) => true,
1106 fn is_trait(&self) -> bool {
1108 ModuleKind::Def(Def::Trait(_), _) => true,
1113 fn is_local(&self) -> bool {
1114 self.normal_ancestor_id.is_local()
1117 fn nearest_item_scope(&'a self) -> Module<'a> {
1118 if self.is_trait() { self.parent.unwrap() } else { self }
1121 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1122 while !ptr::eq(self, other) {
1123 if let Some(parent) = other.parent {
1133 impl<'a> fmt::Debug for ModuleData<'a> {
1134 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1135 write!(f, "{:?}", self.def())
1139 /// Records a possibly-private value, type, or module definition.
1140 #[derive(Clone, Debug)]
1141 pub struct NameBinding<'a> {
1142 kind: NameBindingKind<'a>,
1145 vis: ty::Visibility,
1148 pub trait ToNameBinding<'a> {
1149 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1152 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1153 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1158 #[derive(Clone, Debug)]
1159 enum NameBindingKind<'a> {
1160 Def(Def, /* is_macro_export */ bool),
1163 binding: &'a NameBinding<'a>,
1164 directive: &'a ImportDirective<'a>,
1168 b1: &'a NameBinding<'a>,
1169 b2: &'a NameBinding<'a>,
1173 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1175 struct UseError<'a> {
1176 err: DiagnosticBuilder<'a>,
1177 /// Attach `use` statements for these candidates
1178 candidates: Vec<ImportSuggestion>,
1179 /// The node id of the module to place the use statements in
1181 /// Whether the diagnostic should state that it's "better"
1185 struct AmbiguityError<'a> {
1187 b1: &'a NameBinding<'a>,
1188 b2: &'a NameBinding<'a>,
1191 impl<'a> NameBinding<'a> {
1192 fn module(&self) -> Option<Module<'a>> {
1194 NameBindingKind::Module(module) => Some(module),
1195 NameBindingKind::Import { binding, .. } => binding.module(),
1200 fn def(&self) -> Def {
1202 NameBindingKind::Def(def, _) => def,
1203 NameBindingKind::Module(module) => module.def().unwrap(),
1204 NameBindingKind::Import { binding, .. } => binding.def(),
1205 NameBindingKind::Ambiguity { .. } => Def::Err,
1209 fn def_ignoring_ambiguity(&self) -> Def {
1211 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1212 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1217 // We sometimes need to treat variants as `pub` for backwards compatibility
1218 fn pseudo_vis(&self) -> ty::Visibility {
1219 if self.is_variant() && self.def().def_id().is_local() {
1220 ty::Visibility::Public
1226 fn is_variant(&self) -> bool {
1228 NameBindingKind::Def(Def::Variant(..), _) |
1229 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1234 fn is_extern_crate(&self) -> bool {
1236 NameBindingKind::Import {
1237 directive: &ImportDirective {
1238 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1245 fn is_import(&self) -> bool {
1247 NameBindingKind::Import { .. } => true,
1252 fn is_glob_import(&self) -> bool {
1254 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1255 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1260 fn is_importable(&self) -> bool {
1262 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1267 fn is_macro_def(&self) -> bool {
1269 NameBindingKind::Def(Def::Macro(..), _) => true,
1274 fn macro_kind(&self) -> Option<MacroKind> {
1275 match self.def_ignoring_ambiguity() {
1276 Def::Macro(_, kind) => Some(kind),
1277 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1282 fn descr(&self) -> &'static str {
1283 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1286 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1287 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1288 // Then this function returns `true` if `self` may emerge from a macro *after* that
1289 // in some later round and screw up our previously found resolution.
1290 // See more detailed explanation in
1291 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1292 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1293 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1294 // Expansions are partially ordered, so "may appear after" is an inversion of
1295 // "certainly appears before or simultaneously" and includes unordered cases.
1296 let self_parent_expansion = self.expansion;
1297 let other_parent_expansion = binding.expansion;
1298 let certainly_before_other_or_simultaneously =
1299 other_parent_expansion.is_descendant_of(self_parent_expansion);
1300 let certainly_before_invoc_or_simultaneously =
1301 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1302 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1306 /// Interns the names of the primitive types.
1308 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1309 /// special handling, since they have no place of origin.
1311 struct PrimitiveTypeTable {
1312 primitive_types: FxHashMap<Name, PrimTy>,
1315 impl PrimitiveTypeTable {
1316 fn new() -> PrimitiveTypeTable {
1317 let mut table = PrimitiveTypeTable::default();
1319 table.intern("bool", Bool);
1320 table.intern("char", Char);
1321 table.intern("f32", Float(FloatTy::F32));
1322 table.intern("f64", Float(FloatTy::F64));
1323 table.intern("isize", Int(IntTy::Isize));
1324 table.intern("i8", Int(IntTy::I8));
1325 table.intern("i16", Int(IntTy::I16));
1326 table.intern("i32", Int(IntTy::I32));
1327 table.intern("i64", Int(IntTy::I64));
1328 table.intern("i128", Int(IntTy::I128));
1329 table.intern("str", Str);
1330 table.intern("usize", Uint(UintTy::Usize));
1331 table.intern("u8", Uint(UintTy::U8));
1332 table.intern("u16", Uint(UintTy::U16));
1333 table.intern("u32", Uint(UintTy::U32));
1334 table.intern("u64", Uint(UintTy::U64));
1335 table.intern("u128", Uint(UintTy::U128));
1339 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1340 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1344 #[derive(Default, Clone)]
1345 pub struct ExternPreludeEntry<'a> {
1346 extern_crate_item: Option<&'a NameBinding<'a>>,
1347 pub introduced_by_item: bool,
1350 /// The main resolver class.
1352 /// This is the visitor that walks the whole crate.
1353 pub struct Resolver<'a, 'b: 'a> {
1354 session: &'a Session,
1357 pub definitions: Definitions,
1359 graph_root: Module<'a>,
1361 prelude: Option<Module<'a>>,
1362 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1364 /// n.b. This is used only for better diagnostics, not name resolution itself.
1365 has_self: FxHashSet<DefId>,
1367 /// Names of fields of an item `DefId` accessible with dot syntax.
1368 /// Used for hints during error reporting.
1369 field_names: FxHashMap<DefId, Vec<Name>>,
1371 /// All imports known to succeed or fail.
1372 determined_imports: Vec<&'a ImportDirective<'a>>,
1374 /// All non-determined imports.
1375 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1377 /// The module that represents the current item scope.
1378 current_module: Module<'a>,
1380 /// The current set of local scopes for types and values.
1381 /// FIXME #4948: Reuse ribs to avoid allocation.
1382 ribs: PerNS<Vec<Rib<'a>>>,
1384 /// The current set of local scopes, for labels.
1385 label_ribs: Vec<Rib<'a>>,
1387 /// The trait that the current context can refer to.
1388 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1390 /// The current self type if inside an impl (used for better errors).
1391 current_self_type: Option<Ty>,
1393 /// The current self item if inside an ADT (used for better errors).
1394 current_self_item: Option<NodeId>,
1396 /// The idents for the primitive types.
1397 primitive_type_table: PrimitiveTypeTable,
1400 import_map: ImportMap,
1401 pub freevars: FreevarMap,
1402 freevars_seen: NodeMap<NodeMap<usize>>,
1403 pub export_map: ExportMap,
1404 pub trait_map: TraitMap,
1406 /// A map from nodes to anonymous modules.
1407 /// Anonymous modules are pseudo-modules that are implicitly created around items
1408 /// contained within blocks.
1410 /// For example, if we have this:
1418 /// There will be an anonymous module created around `g` with the ID of the
1419 /// entry block for `f`.
1420 block_map: NodeMap<Module<'a>>,
1421 module_map: FxHashMap<DefId, Module<'a>>,
1422 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1423 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1425 pub make_glob_map: bool,
1426 /// Maps imports to the names of items actually imported (this actually maps
1427 /// all imports, but only glob imports are actually interesting).
1428 pub glob_map: GlobMap,
1430 used_imports: FxHashSet<(NodeId, Namespace)>,
1431 pub maybe_unused_trait_imports: NodeSet,
1432 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1434 /// A list of labels as of yet unused. Labels will be removed from this map when
1435 /// they are used (in a `break` or `continue` statement)
1436 pub unused_labels: FxHashMap<NodeId, Span>,
1438 /// privacy errors are delayed until the end in order to deduplicate them
1439 privacy_errors: Vec<PrivacyError<'a>>,
1440 /// ambiguity errors are delayed for deduplication
1441 ambiguity_errors: Vec<AmbiguityError<'a>>,
1442 /// `use` injections are delayed for better placement and deduplication
1443 use_injections: Vec<UseError<'a>>,
1444 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1445 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1447 arenas: &'a ResolverArenas<'a>,
1448 dummy_binding: &'a NameBinding<'a>,
1450 crate_loader: &'a mut CrateLoader<'b>,
1451 macro_names: FxHashSet<Ident>,
1452 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1453 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1454 pub all_macros: FxHashMap<Name, Def>,
1455 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1456 macro_defs: FxHashMap<Mark, DefId>,
1457 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1458 pub whitelisted_legacy_custom_derives: Vec<Name>,
1459 pub found_unresolved_macro: bool,
1461 /// List of crate local macros that we need to warn about as being unused.
1462 /// Right now this only includes macro_rules! macros, and macros 2.0.
1463 unused_macros: FxHashSet<DefId>,
1465 /// Maps the `Mark` of an expansion to its containing module or block.
1466 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1468 /// Avoid duplicated errors for "name already defined".
1469 name_already_seen: FxHashMap<Name, Span>,
1471 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1473 /// This table maps struct IDs into struct constructor IDs,
1474 /// it's not used during normal resolution, only for better error reporting.
1475 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1477 /// Only used for better errors on `fn(): fn()`
1478 current_type_ascription: Vec<Span>,
1480 injected_crate: Option<Module<'a>>,
1483 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1485 pub struct ResolverArenas<'a> {
1486 modules: arena::TypedArena<ModuleData<'a>>,
1487 local_modules: RefCell<Vec<Module<'a>>>,
1488 name_bindings: arena::TypedArena<NameBinding<'a>>,
1489 import_directives: arena::TypedArena<ImportDirective<'a>>,
1490 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1491 invocation_data: arena::TypedArena<InvocationData<'a>>,
1492 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1495 impl<'a> ResolverArenas<'a> {
1496 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1497 let module = self.modules.alloc(module);
1498 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1499 self.local_modules.borrow_mut().push(module);
1503 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1504 self.local_modules.borrow()
1506 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1507 self.name_bindings.alloc(name_binding)
1509 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1510 -> &'a ImportDirective {
1511 self.import_directives.alloc(import_directive)
1513 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1514 self.name_resolutions.alloc(Default::default())
1516 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1517 -> &'a InvocationData<'a> {
1518 self.invocation_data.alloc(expansion_data)
1520 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1521 self.legacy_bindings.alloc(binding)
1525 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1526 fn parent(self, id: DefId) -> Option<DefId> {
1528 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1529 _ => self.cstore.def_key(id).parent,
1530 }.map(|index| DefId { index, ..id })
1534 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1535 /// the resolver is no longer needed as all the relevant information is inline.
1536 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1537 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1538 self.resolve_hir_path_cb(path, is_value,
1539 |resolver, span, error| resolve_error(resolver, span, error))
1542 fn resolve_str_path(
1545 crate_root: Option<&str>,
1546 components: &[&str],
1547 args: Option<P<hir::GenericArgs>>,
1550 let mut segments = iter::once(keywords::CrateRoot.ident())
1552 crate_root.into_iter()
1553 .chain(components.iter().cloned())
1554 .map(Ident::from_str)
1555 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1557 if let Some(args) = args {
1558 let ident = segments.last().unwrap().ident;
1559 *segments.last_mut().unwrap() = hir::PathSegment {
1566 let mut path = hir::Path {
1569 segments: segments.into(),
1572 self.resolve_hir_path(&mut path, is_value);
1576 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1577 self.def_map.get(&id).cloned()
1580 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1581 self.import_map.get(&id).cloned().unwrap_or_default()
1584 fn definitions(&mut self) -> &mut Definitions {
1585 &mut self.definitions
1589 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1590 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1591 /// isn't something that can be returned because it can't be made to live that long,
1592 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1593 /// just that an error occurred.
1594 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1595 -> Result<hir::Path, ()> {
1597 let mut errored = false;
1599 let mut path = if path_str.starts_with("::") {
1603 segments: iter::once(keywords::CrateRoot.ident()).chain({
1604 path_str.split("::").skip(1).map(Ident::from_str)
1605 }).map(hir::PathSegment::from_ident).collect(),
1611 segments: path_str.split("::").map(Ident::from_str)
1612 .map(hir::PathSegment::from_ident).collect(),
1615 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1616 if errored || path.def == Def::Err {
1623 /// resolve_hir_path, but takes a callback in case there was an error
1624 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1625 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1627 let namespace = if is_value { ValueNS } else { TypeNS };
1628 let hir::Path { ref segments, span, ref mut def } = *path;
1629 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1630 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1631 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1632 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1633 *def = module.def().unwrap(),
1634 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1635 *def = path_res.base_def(),
1636 PathResult::NonModule(..) =>
1637 if let PathResult::Failed(span, msg, _) = self.resolve_path(
1645 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1647 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1648 PathResult::Indeterminate => unreachable!(),
1649 PathResult::Failed(span, msg, _) => {
1650 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1656 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1657 pub fn new(session: &'a Session,
1661 make_glob_map: MakeGlobMap,
1662 crate_loader: &'a mut CrateLoader<'crateloader>,
1663 arenas: &'a ResolverArenas<'a>)
1664 -> Resolver<'a, 'crateloader> {
1665 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1666 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1667 let graph_root = arenas.alloc_module(ModuleData {
1668 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1669 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1671 let mut module_map = FxHashMap::default();
1672 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1674 let mut definitions = Definitions::new();
1675 DefCollector::new(&mut definitions, Mark::root())
1676 .collect_root(crate_name, session.local_crate_disambiguator());
1678 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1679 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1682 if !attr::contains_name(&krate.attrs, "no_core") {
1683 extern_prelude.insert(Ident::from_str("core"), Default::default());
1684 if !attr::contains_name(&krate.attrs, "no_std") {
1685 extern_prelude.insert(Ident::from_str("std"), Default::default());
1686 if session.rust_2018() {
1687 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1692 let mut invocations = FxHashMap::default();
1693 invocations.insert(Mark::root(),
1694 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1696 let mut macro_defs = FxHashMap::default();
1697 macro_defs.insert(Mark::root(), root_def_id);
1706 // The outermost module has def ID 0; this is not reflected in the
1712 has_self: FxHashSet::default(),
1713 field_names: FxHashMap::default(),
1715 determined_imports: Vec::new(),
1716 indeterminate_imports: Vec::new(),
1718 current_module: graph_root,
1720 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1721 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1722 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1724 label_ribs: Vec::new(),
1726 current_trait_ref: None,
1727 current_self_type: None,
1728 current_self_item: None,
1730 primitive_type_table: PrimitiveTypeTable::new(),
1733 import_map: NodeMap(),
1734 freevars: NodeMap(),
1735 freevars_seen: NodeMap(),
1736 export_map: FxHashMap::default(),
1737 trait_map: NodeMap(),
1739 block_map: NodeMap(),
1740 extern_module_map: FxHashMap::default(),
1741 binding_parent_modules: FxHashMap::default(),
1743 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1744 glob_map: NodeMap(),
1746 used_imports: FxHashSet::default(),
1747 maybe_unused_trait_imports: NodeSet(),
1748 maybe_unused_extern_crates: Vec::new(),
1750 unused_labels: FxHashMap::default(),
1752 privacy_errors: Vec::new(),
1753 ambiguity_errors: Vec::new(),
1754 use_injections: Vec::new(),
1755 macro_expanded_macro_export_errors: BTreeSet::new(),
1758 dummy_binding: arenas.alloc_name_binding(NameBinding {
1759 kind: NameBindingKind::Def(Def::Err, false),
1760 expansion: Mark::root(),
1762 vis: ty::Visibility::Public,
1766 macro_names: FxHashSet::default(),
1767 builtin_macros: FxHashMap::default(),
1768 macro_use_prelude: FxHashMap::default(),
1769 all_macros: FxHashMap::default(),
1770 macro_map: FxHashMap::default(),
1773 local_macro_def_scopes: FxHashMap::default(),
1774 name_already_seen: FxHashMap::default(),
1775 whitelisted_legacy_custom_derives: Vec::new(),
1776 potentially_unused_imports: Vec::new(),
1777 struct_constructors: DefIdMap(),
1778 found_unresolved_macro: false,
1779 unused_macros: FxHashSet::default(),
1780 current_type_ascription: Vec::new(),
1781 injected_crate: None,
1785 pub fn arenas() -> ResolverArenas<'a> {
1789 /// Runs the function on each namespace.
1790 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1796 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1798 match self.macro_defs.get(&ctxt.outer()) {
1799 Some(&def_id) => return def_id,
1800 None => ctxt.remove_mark(),
1805 /// Entry point to crate resolution.
1806 pub fn resolve_crate(&mut self, krate: &Crate) {
1807 ImportResolver { resolver: self }.finalize_imports();
1808 self.current_module = self.graph_root;
1809 self.finalize_current_module_macro_resolutions();
1811 visit::walk_crate(self, krate);
1813 check_unused::check_crate(self, krate);
1814 self.report_errors(krate);
1815 self.crate_loader.postprocess(krate);
1822 normal_ancestor_id: DefId,
1826 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1827 self.arenas.alloc_module(module)
1830 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1831 -> bool /* true if an error was reported */ {
1832 match binding.kind {
1833 NameBindingKind::Import { directive, binding, ref used }
1836 directive.used.set(true);
1837 self.used_imports.insert((directive.id, ns));
1838 self.add_to_glob_map(directive.id, ident);
1839 self.record_use(ident, ns, binding)
1841 NameBindingKind::Import { .. } => false,
1842 NameBindingKind::Ambiguity { b1, b2 } => {
1843 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1850 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1851 if self.make_glob_map {
1852 self.glob_map.entry(id).or_default().insert(ident.name);
1856 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1857 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1858 /// `ident` in the first scope that defines it (or None if no scopes define it).
1860 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1861 /// the items are defined in the block. For example,
1864 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1867 /// g(); // This resolves to the local variable `g` since it shadows the item.
1871 /// Invariant: This must only be called during main resolution, not during
1872 /// import resolution.
1873 fn resolve_ident_in_lexical_scope(&mut self,
1876 record_used_id: Option<NodeId>,
1878 -> Option<LexicalScopeBinding<'a>> {
1879 let record_used = record_used_id.is_some();
1880 assert!(ns == TypeNS || ns == ValueNS);
1882 ident.span = if ident.name == keywords::SelfType.name() {
1883 // FIXME(jseyfried) improve `Self` hygiene
1884 ident.span.with_ctxt(SyntaxContext::empty())
1889 ident = ident.modern_and_legacy();
1892 // Walk backwards up the ribs in scope.
1893 let mut module = self.graph_root;
1894 for i in (0 .. self.ribs[ns].len()).rev() {
1895 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1896 // The ident resolves to a type parameter or local variable.
1897 return Some(LexicalScopeBinding::Def(
1898 self.adjust_local_def(ns, i, def, record_used, path_span)
1902 module = match self.ribs[ns][i].kind {
1903 ModuleRibKind(module) => module,
1904 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1905 // If an invocation of this macro created `ident`, give up on `ident`
1906 // and switch to `ident`'s source from the macro definition.
1907 ident.span.remove_mark();
1913 let item = self.resolve_ident_in_module_unadjusted(
1914 ModuleOrUniformRoot::Module(module),
1921 if let Ok(binding) = item {
1922 // The ident resolves to an item.
1923 return Some(LexicalScopeBinding::Item(binding));
1927 ModuleKind::Block(..) => {}, // We can see through blocks
1932 ident.span = ident.span.modern();
1933 let mut poisoned = None;
1935 let opt_module = if let Some(node_id) = record_used_id {
1936 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1937 node_id, &mut poisoned)
1939 self.hygienic_lexical_parent(module, &mut ident.span)
1941 module = unwrap_or!(opt_module, break);
1942 let orig_current_module = self.current_module;
1943 self.current_module = module; // Lexical resolutions can never be a privacy error.
1944 let result = self.resolve_ident_in_module_unadjusted(
1945 ModuleOrUniformRoot::Module(module),
1952 self.current_module = orig_current_module;
1956 if let Some(node_id) = poisoned {
1957 self.session.buffer_lint_with_diagnostic(
1958 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1959 node_id, ident.span,
1960 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1961 lint::builtin::BuiltinLintDiagnostics::
1962 ProcMacroDeriveResolutionFallback(ident.span),
1965 return Some(LexicalScopeBinding::Item(binding))
1967 Err(Determined) => continue,
1968 Err(Undetermined) =>
1969 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1973 if !module.no_implicit_prelude {
1975 if let Some(binding) = self.extern_prelude_get(ident, !record_used, false) {
1976 return Some(LexicalScopeBinding::Item(binding));
1979 if ns == TypeNS && is_known_tool(ident.name) {
1980 let binding = (Def::ToolMod, ty::Visibility::Public,
1981 ident.span, Mark::root()).to_name_binding(self.arenas);
1982 return Some(LexicalScopeBinding::Item(binding));
1984 if let Some(prelude) = self.prelude {
1985 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1986 ModuleOrUniformRoot::Module(prelude),
1993 return Some(LexicalScopeBinding::Item(binding));
2001 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2002 -> Option<Module<'a>> {
2003 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2004 return Some(self.macro_def_scope(span.remove_mark()));
2007 if let ModuleKind::Block(..) = module.kind {
2008 return Some(module.parent.unwrap());
2014 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2015 span: &mut Span, node_id: NodeId,
2016 poisoned: &mut Option<NodeId>)
2017 -> Option<Module<'a>> {
2018 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2022 // We need to support the next case under a deprecation warning
2025 // ---- begin: this comes from a proc macro derive
2026 // mod implementation_details {
2027 // // Note that `MyStruct` is not in scope here.
2028 // impl SomeTrait for MyStruct { ... }
2032 // So we have to fall back to the module's parent during lexical resolution in this case.
2033 if let Some(parent) = module.parent {
2034 // Inner module is inside the macro, parent module is outside of the macro.
2035 if module.expansion != parent.expansion &&
2036 module.expansion.is_descendant_of(parent.expansion) {
2037 // The macro is a proc macro derive
2038 if module.expansion.looks_like_proc_macro_derive() {
2039 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2040 *poisoned = Some(node_id);
2041 return module.parent;
2050 fn resolve_ident_in_module(&mut self,
2051 module: ModuleOrUniformRoot<'a>,
2056 -> Result<&'a NameBinding<'a>, Determinacy> {
2057 ident.span = ident.span.modern();
2058 let orig_current_module = self.current_module;
2059 if let ModuleOrUniformRoot::Module(module) = module {
2060 if let Some(def) = ident.span.adjust(module.expansion) {
2061 self.current_module = self.macro_def_scope(def);
2064 let result = self.resolve_ident_in_module_unadjusted(
2065 module, ident, ns, false, record_used, span,
2067 self.current_module = orig_current_module;
2071 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2072 let mut ctxt = ident.span.ctxt();
2073 let mark = if ident.name == keywords::DollarCrate.name() {
2074 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2075 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2076 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2077 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2078 // definitions actually produced by `macro` and `macro` definitions produced by
2079 // `macro_rules!`, but at least such configurations are not stable yet.
2080 ctxt = ctxt.modern_and_legacy();
2081 let mut iter = ctxt.marks().into_iter().rev().peekable();
2082 let mut result = None;
2083 // Find the last modern mark from the end if it exists.
2084 while let Some(&(mark, transparency)) = iter.peek() {
2085 if transparency == Transparency::Opaque {
2086 result = Some(mark);
2092 // Then find the last legacy mark from the end if it exists.
2093 for (mark, transparency) in iter {
2094 if transparency == Transparency::SemiTransparent {
2095 result = Some(mark);
2102 ctxt = ctxt.modern();
2103 ctxt.adjust(Mark::root())
2105 let module = match mark {
2106 Some(def) => self.macro_def_scope(def),
2107 None => return self.graph_root,
2109 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2112 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2113 let mut module = self.get_module(module.normal_ancestor_id);
2114 while module.span.ctxt().modern() != *ctxt {
2115 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2116 module = self.get_module(parent.normal_ancestor_id);
2123 // We maintain a list of value ribs and type ribs.
2125 // Simultaneously, we keep track of the current position in the module
2126 // graph in the `current_module` pointer. When we go to resolve a name in
2127 // the value or type namespaces, we first look through all the ribs and
2128 // then query the module graph. When we resolve a name in the module
2129 // namespace, we can skip all the ribs (since nested modules are not
2130 // allowed within blocks in Rust) and jump straight to the current module
2133 // Named implementations are handled separately. When we find a method
2134 // call, we consult the module node to find all of the implementations in
2135 // scope. This information is lazily cached in the module node. We then
2136 // generate a fake "implementation scope" containing all the
2137 // implementations thus found, for compatibility with old resolve pass.
2139 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2140 where F: FnOnce(&mut Resolver) -> T
2142 let id = self.definitions.local_def_id(id);
2143 let module = self.module_map.get(&id).cloned(); // clones a reference
2144 if let Some(module) = module {
2145 // Move down in the graph.
2146 let orig_module = replace(&mut self.current_module, module);
2147 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2148 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2150 self.finalize_current_module_macro_resolutions();
2153 self.current_module = orig_module;
2154 self.ribs[ValueNS].pop();
2155 self.ribs[TypeNS].pop();
2162 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2163 /// is returned by the given predicate function
2165 /// Stops after meeting a closure.
2166 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2167 where P: Fn(&Rib, Ident) -> Option<R>
2169 for rib in self.label_ribs.iter().rev() {
2172 // If an invocation of this macro created `ident`, give up on `ident`
2173 // and switch to `ident`'s source from the macro definition.
2174 MacroDefinition(def) => {
2175 if def == self.macro_def(ident.span.ctxt()) {
2176 ident.span.remove_mark();
2180 // Do not resolve labels across function boundary
2184 let r = pred(rib, ident);
2192 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2193 self.with_current_self_item(item, |this| {
2194 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2195 let item_def_id = this.definitions.local_def_id(item.id);
2196 if this.session.features_untracked().self_in_typedefs {
2197 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2198 visit::walk_item(this, item);
2201 visit::walk_item(this, item);
2207 fn resolve_item(&mut self, item: &Item) {
2208 let name = item.ident.name;
2209 debug!("(resolving item) resolving {}", name);
2212 ItemKind::Ty(_, ref generics) |
2213 ItemKind::Fn(_, _, ref generics, _) |
2214 ItemKind::Existential(_, ref generics) => {
2215 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2216 |this| visit::walk_item(this, item));
2219 ItemKind::Enum(_, ref generics) |
2220 ItemKind::Struct(_, ref generics) |
2221 ItemKind::Union(_, ref generics) => {
2222 self.resolve_adt(item, generics);
2225 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2226 self.resolve_implementation(generics,
2232 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2233 // Create a new rib for the trait-wide type parameters.
2234 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2235 let local_def_id = this.definitions.local_def_id(item.id);
2236 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2237 this.visit_generics(generics);
2238 walk_list!(this, visit_param_bound, bounds);
2240 for trait_item in trait_items {
2241 let type_parameters = HasTypeParameters(&trait_item.generics,
2242 TraitOrImplItemRibKind);
2243 this.with_type_parameter_rib(type_parameters, |this| {
2244 match trait_item.node {
2245 TraitItemKind::Const(ref ty, ref default) => {
2248 // Only impose the restrictions of
2249 // ConstRibKind for an actual constant
2250 // expression in a provided default.
2251 if let Some(ref expr) = *default{
2252 this.with_constant_rib(|this| {
2253 this.visit_expr(expr);
2257 TraitItemKind::Method(_, _) => {
2258 visit::walk_trait_item(this, trait_item)
2260 TraitItemKind::Type(..) => {
2261 visit::walk_trait_item(this, trait_item)
2263 TraitItemKind::Macro(_) => {
2264 panic!("unexpanded macro in resolve!")
2273 ItemKind::TraitAlias(ref generics, ref bounds) => {
2274 // Create a new rib for the trait-wide type parameters.
2275 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2276 let local_def_id = this.definitions.local_def_id(item.id);
2277 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2278 this.visit_generics(generics);
2279 walk_list!(this, visit_param_bound, bounds);
2284 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2285 self.with_scope(item.id, |this| {
2286 visit::walk_item(this, item);
2290 ItemKind::Static(ref ty, _, ref expr) |
2291 ItemKind::Const(ref ty, ref expr) => {
2292 self.with_item_rib(|this| {
2294 this.with_constant_rib(|this| {
2295 this.visit_expr(expr);
2300 ItemKind::Use(ref use_tree) => {
2301 // Imports are resolved as global by default, add starting root segment.
2303 segments: use_tree.prefix.make_root().into_iter().collect(),
2304 span: use_tree.span,
2306 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2309 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2310 // do nothing, these are just around to be encoded
2313 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2317 /// For the most part, use trees are desugared into `ImportDirective` instances
2318 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2319 /// there is one special case we handle here: an empty nested import like
2320 /// `a::{b::{}}`, which desugares into...no import directives.
2321 fn resolve_use_tree(
2326 use_tree: &ast::UseTree,
2329 match use_tree.kind {
2330 ast::UseTreeKind::Nested(ref items) => {
2332 segments: prefix.segments
2334 .chain(use_tree.prefix.segments.iter())
2337 span: prefix.span.to(use_tree.prefix.span),
2340 if items.is_empty() {
2341 // Resolve prefix of an import with empty braces (issue #28388).
2342 self.smart_resolve_path_with_crate_lint(
2346 PathSource::ImportPrefix,
2347 CrateLint::UsePath { root_id, root_span },
2350 for &(ref tree, nested_id) in items {
2351 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2355 ast::UseTreeKind::Simple(..) => {},
2356 ast::UseTreeKind::Glob => {},
2360 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2361 where F: FnOnce(&mut Resolver)
2363 match type_parameters {
2364 HasTypeParameters(generics, rib_kind) => {
2365 let mut function_type_rib = Rib::new(rib_kind);
2366 let mut seen_bindings = FxHashMap::default();
2367 for param in &generics.params {
2369 GenericParamKind::Lifetime { .. } => {}
2370 GenericParamKind::Type { .. } => {
2371 let ident = param.ident.modern();
2372 debug!("with_type_parameter_rib: {}", param.id);
2374 if seen_bindings.contains_key(&ident) {
2375 let span = seen_bindings.get(&ident).unwrap();
2376 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2380 resolve_error(self, param.ident.span, err);
2382 seen_bindings.entry(ident).or_insert(param.ident.span);
2384 // Plain insert (no renaming).
2385 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2386 function_type_rib.bindings.insert(ident, def);
2387 self.record_def(param.id, PathResolution::new(def));
2391 self.ribs[TypeNS].push(function_type_rib);
2394 NoTypeParameters => {
2401 if let HasTypeParameters(..) = type_parameters {
2402 self.ribs[TypeNS].pop();
2406 fn with_label_rib<F>(&mut self, f: F)
2407 where F: FnOnce(&mut Resolver)
2409 self.label_ribs.push(Rib::new(NormalRibKind));
2411 self.label_ribs.pop();
2414 fn with_item_rib<F>(&mut self, f: F)
2415 where F: FnOnce(&mut Resolver)
2417 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2418 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2420 self.ribs[TypeNS].pop();
2421 self.ribs[ValueNS].pop();
2424 fn with_constant_rib<F>(&mut self, f: F)
2425 where F: FnOnce(&mut Resolver)
2427 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2428 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2430 self.label_ribs.pop();
2431 self.ribs[ValueNS].pop();
2434 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2435 where F: FnOnce(&mut Resolver) -> T
2437 // Handle nested impls (inside fn bodies)
2438 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2439 let result = f(self);
2440 self.current_self_type = previous_value;
2444 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2445 where F: FnOnce(&mut Resolver) -> T
2447 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2448 let result = f(self);
2449 self.current_self_item = previous_value;
2453 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2454 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2455 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2457 let mut new_val = None;
2458 let mut new_id = None;
2459 if let Some(trait_ref) = opt_trait_ref {
2460 let path: Vec<_> = trait_ref.path.segments.iter()
2461 .map(|seg| seg.ident)
2463 let def = self.smart_resolve_path_fragment(
2467 trait_ref.path.span,
2468 PathSource::Trait(AliasPossibility::No),
2469 CrateLint::SimplePath(trait_ref.ref_id),
2471 if def != Def::Err {
2472 new_id = Some(def.def_id());
2473 let span = trait_ref.path.span;
2474 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2481 CrateLint::SimplePath(trait_ref.ref_id),
2484 new_val = Some((module, trait_ref.clone()));
2488 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2489 let result = f(self, new_id);
2490 self.current_trait_ref = original_trait_ref;
2494 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2495 where F: FnOnce(&mut Resolver)
2497 let mut self_type_rib = Rib::new(NormalRibKind);
2499 // plain insert (no renaming, types are not currently hygienic....)
2500 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2501 self.ribs[TypeNS].push(self_type_rib);
2503 self.ribs[TypeNS].pop();
2506 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2507 where F: FnOnce(&mut Resolver)
2509 let self_def = Def::SelfCtor(impl_id);
2510 let mut self_type_rib = Rib::new(NormalRibKind);
2511 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2512 self.ribs[ValueNS].push(self_type_rib);
2514 self.ribs[ValueNS].pop();
2517 fn resolve_implementation(&mut self,
2518 generics: &Generics,
2519 opt_trait_reference: &Option<TraitRef>,
2522 impl_items: &[ImplItem]) {
2523 // If applicable, create a rib for the type parameters.
2524 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2525 // Dummy self type for better errors if `Self` is used in the trait path.
2526 this.with_self_rib(Def::SelfTy(None, None), |this| {
2527 // Resolve the trait reference, if necessary.
2528 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2529 let item_def_id = this.definitions.local_def_id(item_id);
2530 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2531 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2532 // Resolve type arguments in the trait path.
2533 visit::walk_trait_ref(this, trait_ref);
2535 // Resolve the self type.
2536 this.visit_ty(self_type);
2537 // Resolve the type parameters.
2538 this.visit_generics(generics);
2539 // Resolve the items within the impl.
2540 this.with_current_self_type(self_type, |this| {
2541 this.with_self_struct_ctor_rib(item_def_id, |this| {
2542 for impl_item in impl_items {
2543 this.resolve_visibility(&impl_item.vis);
2545 // We also need a new scope for the impl item type parameters.
2546 let type_parameters = HasTypeParameters(&impl_item.generics,
2547 TraitOrImplItemRibKind);
2548 this.with_type_parameter_rib(type_parameters, |this| {
2549 use self::ResolutionError::*;
2550 match impl_item.node {
2551 ImplItemKind::Const(..) => {
2552 // If this is a trait impl, ensure the const
2554 this.check_trait_item(impl_item.ident,
2557 |n, s| ConstNotMemberOfTrait(n, s));
2558 this.with_constant_rib(|this|
2559 visit::walk_impl_item(this, impl_item)
2562 ImplItemKind::Method(..) => {
2563 // If this is a trait impl, ensure the method
2565 this.check_trait_item(impl_item.ident,
2568 |n, s| MethodNotMemberOfTrait(n, s));
2570 visit::walk_impl_item(this, impl_item);
2572 ImplItemKind::Type(ref ty) => {
2573 // If this is a trait impl, ensure the type
2575 this.check_trait_item(impl_item.ident,
2578 |n, s| TypeNotMemberOfTrait(n, s));
2582 ImplItemKind::Existential(ref bounds) => {
2583 // If this is a trait impl, ensure the type
2585 this.check_trait_item(impl_item.ident,
2588 |n, s| TypeNotMemberOfTrait(n, s));
2590 for bound in bounds {
2591 this.visit_param_bound(bound);
2594 ImplItemKind::Macro(_) =>
2595 panic!("unexpanded macro in resolve!"),
2607 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2608 where F: FnOnce(Name, &str) -> ResolutionError
2610 // If there is a TraitRef in scope for an impl, then the method must be in the
2612 if let Some((module, _)) = self.current_trait_ref {
2613 if self.resolve_ident_in_module(
2614 ModuleOrUniformRoot::Module(module),
2620 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2621 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2626 fn resolve_local(&mut self, local: &Local) {
2627 // Resolve the type.
2628 walk_list!(self, visit_ty, &local.ty);
2630 // Resolve the initializer.
2631 walk_list!(self, visit_expr, &local.init);
2633 // Resolve the pattern.
2634 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2637 // build a map from pattern identifiers to binding-info's.
2638 // this is done hygienically. This could arise for a macro
2639 // that expands into an or-pattern where one 'x' was from the
2640 // user and one 'x' came from the macro.
2641 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2642 let mut binding_map = FxHashMap::default();
2644 pat.walk(&mut |pat| {
2645 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2646 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2647 Some(Def::Local(..)) => true,
2650 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2651 binding_map.insert(ident, binding_info);
2660 // check that all of the arms in an or-pattern have exactly the
2661 // same set of bindings, with the same binding modes for each.
2662 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2663 if pats.is_empty() {
2667 let mut missing_vars = FxHashMap::default();
2668 let mut inconsistent_vars = FxHashMap::default();
2669 for (i, p) in pats.iter().enumerate() {
2670 let map_i = self.binding_mode_map(&p);
2672 for (j, q) in pats.iter().enumerate() {
2677 let map_j = self.binding_mode_map(&q);
2678 for (&key, &binding_i) in &map_i {
2679 if map_j.is_empty() { // Account for missing bindings when
2680 let binding_error = missing_vars // map_j has none.
2682 .or_insert(BindingError {
2684 origin: BTreeSet::new(),
2685 target: BTreeSet::new(),
2687 binding_error.origin.insert(binding_i.span);
2688 binding_error.target.insert(q.span);
2690 for (&key_j, &binding_j) in &map_j {
2691 match map_i.get(&key_j) {
2692 None => { // missing binding
2693 let binding_error = missing_vars
2695 .or_insert(BindingError {
2697 origin: BTreeSet::new(),
2698 target: BTreeSet::new(),
2700 binding_error.origin.insert(binding_j.span);
2701 binding_error.target.insert(p.span);
2703 Some(binding_i) => { // check consistent binding
2704 if binding_i.binding_mode != binding_j.binding_mode {
2707 .or_insert((binding_j.span, binding_i.span));
2715 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2716 missing_vars.sort();
2717 for (_, v) in missing_vars {
2719 *v.origin.iter().next().unwrap(),
2720 ResolutionError::VariableNotBoundInPattern(v));
2722 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2723 inconsistent_vars.sort();
2724 for (name, v) in inconsistent_vars {
2725 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2729 fn resolve_arm(&mut self, arm: &Arm) {
2730 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2732 let mut bindings_list = FxHashMap::default();
2733 for pattern in &arm.pats {
2734 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2737 // This has to happen *after* we determine which pat_idents are variants
2738 self.check_consistent_bindings(&arm.pats);
2740 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2741 self.visit_expr(expr)
2743 self.visit_expr(&arm.body);
2745 self.ribs[ValueNS].pop();
2748 fn resolve_block(&mut self, block: &Block) {
2749 debug!("(resolving block) entering block");
2750 // Move down in the graph, if there's an anonymous module rooted here.
2751 let orig_module = self.current_module;
2752 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2754 let mut num_macro_definition_ribs = 0;
2755 if let Some(anonymous_module) = anonymous_module {
2756 debug!("(resolving block) found anonymous module, moving down");
2757 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2758 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2759 self.current_module = anonymous_module;
2760 self.finalize_current_module_macro_resolutions();
2762 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2765 // Descend into the block.
2766 for stmt in &block.stmts {
2767 if let ast::StmtKind::Item(ref item) = stmt.node {
2768 if let ast::ItemKind::MacroDef(..) = item.node {
2769 num_macro_definition_ribs += 1;
2770 let def = self.definitions.local_def_id(item.id);
2771 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2772 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2776 self.visit_stmt(stmt);
2780 self.current_module = orig_module;
2781 for _ in 0 .. num_macro_definition_ribs {
2782 self.ribs[ValueNS].pop();
2783 self.label_ribs.pop();
2785 self.ribs[ValueNS].pop();
2786 if anonymous_module.is_some() {
2787 self.ribs[TypeNS].pop();
2789 debug!("(resolving block) leaving block");
2792 fn fresh_binding(&mut self,
2795 outer_pat_id: NodeId,
2796 pat_src: PatternSource,
2797 bindings: &mut FxHashMap<Ident, NodeId>)
2799 // Add the binding to the local ribs, if it
2800 // doesn't already exist in the bindings map. (We
2801 // must not add it if it's in the bindings map
2802 // because that breaks the assumptions later
2803 // passes make about or-patterns.)
2804 let ident = ident.modern_and_legacy();
2805 let mut def = Def::Local(pat_id);
2806 match bindings.get(&ident).cloned() {
2807 Some(id) if id == outer_pat_id => {
2808 // `Variant(a, a)`, error
2812 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2816 Some(..) if pat_src == PatternSource::FnParam => {
2817 // `fn f(a: u8, a: u8)`, error
2821 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2825 Some(..) if pat_src == PatternSource::Match ||
2826 pat_src == PatternSource::IfLet ||
2827 pat_src == PatternSource::WhileLet => {
2828 // `Variant1(a) | Variant2(a)`, ok
2829 // Reuse definition from the first `a`.
2830 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2833 span_bug!(ident.span, "two bindings with the same name from \
2834 unexpected pattern source {:?}", pat_src);
2837 // A completely fresh binding, add to the lists if it's valid.
2838 if ident.name != keywords::Invalid.name() {
2839 bindings.insert(ident, outer_pat_id);
2840 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2845 PathResolution::new(def)
2848 fn resolve_pattern(&mut self,
2850 pat_src: PatternSource,
2851 // Maps idents to the node ID for the
2852 // outermost pattern that binds them.
2853 bindings: &mut FxHashMap<Ident, NodeId>) {
2854 // Visit all direct subpatterns of this pattern.
2855 let outer_pat_id = pat.id;
2856 pat.walk(&mut |pat| {
2858 PatKind::Ident(bmode, ident, ref opt_pat) => {
2859 // First try to resolve the identifier as some existing
2860 // entity, then fall back to a fresh binding.
2861 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2863 .and_then(LexicalScopeBinding::item);
2864 let resolution = binding.map(NameBinding::def).and_then(|def| {
2865 let is_syntactic_ambiguity = opt_pat.is_none() &&
2866 bmode == BindingMode::ByValue(Mutability::Immutable);
2868 Def::StructCtor(_, CtorKind::Const) |
2869 Def::VariantCtor(_, CtorKind::Const) |
2870 Def::Const(..) if is_syntactic_ambiguity => {
2871 // Disambiguate in favor of a unit struct/variant
2872 // or constant pattern.
2873 self.record_use(ident, ValueNS, binding.unwrap());
2874 Some(PathResolution::new(def))
2876 Def::StructCtor(..) | Def::VariantCtor(..) |
2877 Def::Const(..) | Def::Static(..) => {
2878 // This is unambiguously a fresh binding, either syntactically
2879 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2880 // to something unusable as a pattern (e.g. constructor function),
2881 // but we still conservatively report an error, see
2882 // issues/33118#issuecomment-233962221 for one reason why.
2886 ResolutionError::BindingShadowsSomethingUnacceptable(
2887 pat_src.descr(), ident.name, binding.unwrap())
2891 Def::Fn(..) | Def::Err => {
2892 // These entities are explicitly allowed
2893 // to be shadowed by fresh bindings.
2897 span_bug!(ident.span, "unexpected definition for an \
2898 identifier in pattern: {:?}", def);
2901 }).unwrap_or_else(|| {
2902 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2905 self.record_def(pat.id, resolution);
2908 PatKind::TupleStruct(ref path, ..) => {
2909 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2912 PatKind::Path(ref qself, ref path) => {
2913 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2916 PatKind::Struct(ref path, ..) => {
2917 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2925 visit::walk_pat(self, pat);
2928 // High-level and context dependent path resolution routine.
2929 // Resolves the path and records the resolution into definition map.
2930 // If resolution fails tries several techniques to find likely
2931 // resolution candidates, suggest imports or other help, and report
2932 // errors in user friendly way.
2933 fn smart_resolve_path(&mut self,
2935 qself: Option<&QSelf>,
2939 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2942 /// A variant of `smart_resolve_path` where you also specify extra
2943 /// information about where the path came from; this extra info is
2944 /// sometimes needed for the lint that recommends rewriting
2945 /// absolute paths to `crate`, so that it knows how to frame the
2946 /// suggestion. If you are just resolving a path like `foo::bar`
2947 /// that appears...somewhere, though, then you just want
2948 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2949 /// already provides.
2950 fn smart_resolve_path_with_crate_lint(
2953 qself: Option<&QSelf>,
2956 crate_lint: CrateLint
2957 ) -> PathResolution {
2958 let segments = &path.segments.iter()
2959 .map(|seg| seg.ident)
2960 .collect::<Vec<_>>();
2961 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2964 fn smart_resolve_path_fragment(&mut self,
2966 qself: Option<&QSelf>,
2970 crate_lint: CrateLint)
2972 let ident_span = path.last().map_or(span, |ident| ident.span);
2973 let ns = source.namespace();
2974 let is_expected = &|def| source.is_expected(def);
2975 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2977 // Base error is amended with one short label and possibly some longer helps/notes.
2978 let report_errors = |this: &mut Self, def: Option<Def>| {
2979 // Make the base error.
2980 let expected = source.descr_expected();
2981 let path_str = names_to_string(path);
2982 let item_str = path.last().unwrap();
2983 let code = source.error_code(def.is_some());
2984 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2985 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2986 format!("not a {}", expected),
2989 let item_span = path.last().unwrap().span;
2990 let (mod_prefix, mod_str) = if path.len() == 1 {
2991 (String::new(), "this scope".to_string())
2992 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2993 (String::new(), "the crate root".to_string())
2995 let mod_path = &path[..path.len() - 1];
2996 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2997 false, span, CrateLint::No) {
2998 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3001 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3002 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
3004 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3005 format!("not found in {}", mod_str),
3008 let code = DiagnosticId::Error(code.into());
3009 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3011 // Emit help message for fake-self from other languages like `this`(javascript)
3012 if ["this", "my"].contains(&&*item_str.as_str())
3013 && this.self_value_is_available(path[0].span, span) {
3014 err.span_suggestion_with_applicability(
3018 Applicability::MaybeIncorrect,
3022 // Emit special messages for unresolved `Self` and `self`.
3023 if is_self_type(path, ns) {
3024 __diagnostic_used!(E0411);
3025 err.code(DiagnosticId::Error("E0411".into()));
3026 let available_in = if this.session.features_untracked().self_in_typedefs {
3027 "impls, traits, and type definitions"
3031 err.span_label(span, format!("`Self` is only available in {}", available_in));
3032 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3033 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3036 return (err, Vec::new());
3038 if is_self_value(path, ns) {
3039 __diagnostic_used!(E0424);
3040 err.code(DiagnosticId::Error("E0424".into()));
3041 err.span_label(span, format!("`self` value is a keyword \
3043 methods with `self` parameter"));
3044 return (err, Vec::new());
3047 // Try to lookup the name in more relaxed fashion for better error reporting.
3048 let ident = *path.last().unwrap();
3049 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3050 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3051 let enum_candidates =
3052 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3053 let mut enum_candidates = enum_candidates.iter()
3054 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3055 enum_candidates.sort();
3056 for (sp, variant_path, enum_path) in enum_candidates {
3058 let msg = format!("there is an enum variant `{}`, \
3064 err.span_suggestion_with_applicability(
3066 "you can try using the variant's enum",
3068 Applicability::MachineApplicable,
3073 if path.len() == 1 && this.self_type_is_available(span) {
3074 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3075 let self_is_available = this.self_value_is_available(path[0].span, span);
3077 AssocSuggestion::Field => {
3078 err.span_suggestion_with_applicability(
3081 format!("self.{}", path_str),
3082 Applicability::MachineApplicable,
3084 if !self_is_available {
3085 err.span_label(span, format!("`self` value is a keyword \
3087 methods with `self` parameter"));
3090 AssocSuggestion::MethodWithSelf if self_is_available => {
3091 err.span_suggestion_with_applicability(
3094 format!("self.{}", path_str),
3095 Applicability::MachineApplicable,
3098 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3099 err.span_suggestion_with_applicability(
3102 format!("Self::{}", path_str),
3103 Applicability::MachineApplicable,
3107 return (err, candidates);
3111 let mut levenshtein_worked = false;
3114 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3115 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3116 levenshtein_worked = true;
3119 // Try context dependent help if relaxed lookup didn't work.
3120 if let Some(def) = def {
3121 match (def, source) {
3122 (Def::Macro(..), _) => {
3123 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3124 return (err, candidates);
3126 (Def::TyAlias(..), PathSource::Trait(_)) => {
3127 err.span_label(span, "type aliases cannot be used for traits");
3128 return (err, candidates);
3130 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3131 ExprKind::Field(_, ident) => {
3132 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3134 return (err, candidates);
3136 ExprKind::MethodCall(ref segment, ..) => {
3137 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3138 path_str, segment.ident));
3139 return (err, candidates);
3143 (Def::Enum(..), PathSource::TupleStruct)
3144 | (Def::Enum(..), PathSource::Expr(..)) => {
3145 if let Some(variants) = this.collect_enum_variants(def) {
3146 err.note(&format!("did you mean to use one \
3147 of the following variants?\n{}",
3149 .map(|suggestion| path_names_to_string(suggestion))
3150 .map(|suggestion| format!("- `{}`", suggestion))
3151 .collect::<Vec<_>>()
3155 err.note("did you mean to use one of the enum's variants?");
3157 return (err, candidates);
3159 (Def::Struct(def_id), _) if ns == ValueNS => {
3160 if let Some((ctor_def, ctor_vis))
3161 = this.struct_constructors.get(&def_id).cloned() {
3162 let accessible_ctor = this.is_accessible(ctor_vis);
3163 if is_expected(ctor_def) && !accessible_ctor {
3164 err.span_label(span, format!("constructor is not visible \
3165 here due to private fields"));
3168 // HACK(estebank): find a better way to figure out that this was a
3169 // parser issue where a struct literal is being used on an expression
3170 // where a brace being opened means a block is being started. Look
3171 // ahead for the next text to see if `span` is followed by a `{`.
3172 let sm = this.session.source_map();
3175 sp = sm.next_point(sp);
3176 match sm.span_to_snippet(sp) {
3177 Ok(ref snippet) => {
3178 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3185 let followed_by_brace = match sm.span_to_snippet(sp) {
3186 Ok(ref snippet) if snippet == "{" => true,
3190 PathSource::Expr(Some(parent)) => {
3192 ExprKind::MethodCall(ref path_assignment, _) => {
3193 err.span_suggestion_with_applicability(
3194 sm.start_point(parent.span)
3195 .to(path_assignment.ident.span),
3196 "use `::` to access an associated function",
3199 path_assignment.ident),
3200 Applicability::MaybeIncorrect
3202 return (err, candidates);
3207 format!("did you mean `{} {{ /* fields */ }}`?",
3210 return (err, candidates);
3214 PathSource::Expr(None) if followed_by_brace == true => {
3217 format!("did you mean `({} {{ /* fields */ }})`?",
3220 return (err, candidates);
3225 format!("did you mean `{} {{ /* fields */ }}`?",
3228 return (err, candidates);
3232 return (err, candidates);
3234 (Def::Union(..), _) |
3235 (Def::Variant(..), _) |
3236 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3237 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3239 return (err, candidates);
3241 (Def::SelfTy(..), _) if ns == ValueNS => {
3242 err.span_label(span, fallback_label);
3243 err.note("can't use `Self` as a constructor, you must use the \
3244 implemented struct");
3245 return (err, candidates);
3247 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3248 err.note("can't use a type alias as a constructor");
3249 return (err, candidates);
3256 if !levenshtein_worked {
3257 err.span_label(base_span, fallback_label);
3258 this.type_ascription_suggestion(&mut err, base_span);
3262 let report_errors = |this: &mut Self, def: Option<Def>| {
3263 let (err, candidates) = report_errors(this, def);
3264 let def_id = this.current_module.normal_ancestor_id;
3265 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3266 let better = def.is_some();
3267 this.use_injections.push(UseError { err, candidates, node_id, better });
3268 err_path_resolution()
3271 let resolution = match self.resolve_qpath_anywhere(
3277 source.defer_to_typeck(),
3278 source.global_by_default(),
3281 Some(resolution) if resolution.unresolved_segments() == 0 => {
3282 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3285 // Add a temporary hack to smooth the transition to new struct ctor
3286 // visibility rules. See #38932 for more details.
3288 if let Def::Struct(def_id) = resolution.base_def() {
3289 if let Some((ctor_def, ctor_vis))
3290 = self.struct_constructors.get(&def_id).cloned() {
3291 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3292 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3293 self.session.buffer_lint(lint, id, span,
3294 "private struct constructors are not usable through \
3295 re-exports in outer modules",
3297 res = Some(PathResolution::new(ctor_def));
3302 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3305 Some(resolution) if source.defer_to_typeck() => {
3306 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3307 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3308 // it needs to be added to the trait map.
3310 let item_name = *path.last().unwrap();
3311 let traits = self.get_traits_containing_item(item_name, ns);
3312 self.trait_map.insert(id, traits);
3316 _ => report_errors(self, None)
3319 if let PathSource::TraitItem(..) = source {} else {
3320 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3321 self.record_def(id, resolution);
3326 fn type_ascription_suggestion(&self,
3327 err: &mut DiagnosticBuilder,
3329 debug!("type_ascription_suggetion {:?}", base_span);
3330 let cm = self.session.source_map();
3331 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3332 if let Some(sp) = self.current_type_ascription.last() {
3334 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3335 sp = cm.next_point(sp);
3336 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3337 debug!("snippet {:?}", snippet);
3338 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3339 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3340 debug!("{:?} {:?}", line_sp, line_base_sp);
3342 err.span_label(base_span,
3343 "expecting a type here because of type ascription");
3344 if line_sp != line_base_sp {
3345 err.span_suggestion_short_with_applicability(
3347 "did you mean to use `;` here instead?",
3349 Applicability::MaybeIncorrect,
3353 } else if !snippet.trim().is_empty() {
3354 debug!("tried to find type ascription `:` token, couldn't find it");
3364 fn self_type_is_available(&mut self, span: Span) -> bool {
3365 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3366 TypeNS, None, span);
3367 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3370 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3371 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3372 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3373 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3376 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3377 fn resolve_qpath_anywhere(&mut self,
3379 qself: Option<&QSelf>,
3381 primary_ns: Namespace,
3383 defer_to_typeck: bool,
3384 global_by_default: bool,
3385 crate_lint: CrateLint)
3386 -> Option<PathResolution> {
3387 let mut fin_res = None;
3388 // FIXME: can't resolve paths in macro namespace yet, macros are
3389 // processed by the little special hack below.
3390 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3391 if i == 0 || ns != primary_ns {
3392 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3393 // If defer_to_typeck, then resolution > no resolution,
3394 // otherwise full resolution > partial resolution > no resolution.
3395 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3397 res => if fin_res.is_none() { fin_res = res },
3401 if primary_ns != MacroNS &&
3402 (self.macro_names.contains(&path[0].modern()) ||
3403 self.builtin_macros.get(&path[0].name).cloned()
3404 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3405 self.macro_use_prelude.get(&path[0].name).cloned()
3406 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3407 // Return some dummy definition, it's enough for error reporting.
3409 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3415 /// Handles paths that may refer to associated items.
3416 fn resolve_qpath(&mut self,
3418 qself: Option<&QSelf>,
3422 global_by_default: bool,
3423 crate_lint: CrateLint)
3424 -> Option<PathResolution> {
3426 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3427 ns={:?}, span={:?}, global_by_default={:?})",
3436 if let Some(qself) = qself {
3437 if qself.position == 0 {
3438 // This is a case like `<T>::B`, where there is no
3439 // trait to resolve. In that case, we leave the `B`
3440 // segment to be resolved by type-check.
3441 return Some(PathResolution::with_unresolved_segments(
3442 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3446 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3448 // Currently, `path` names the full item (`A::B::C`, in
3449 // our example). so we extract the prefix of that that is
3450 // the trait (the slice upto and including
3451 // `qself.position`). And then we recursively resolve that,
3452 // but with `qself` set to `None`.
3454 // However, setting `qself` to none (but not changing the
3455 // span) loses the information about where this path
3456 // *actually* appears, so for the purposes of the crate
3457 // lint we pass along information that this is the trait
3458 // name from a fully qualified path, and this also
3459 // contains the full span (the `CrateLint::QPathTrait`).
3460 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3461 let res = self.smart_resolve_path_fragment(
3464 &path[..qself.position + 1],
3466 PathSource::TraitItem(ns),
3467 CrateLint::QPathTrait {
3469 qpath_span: qself.path_span,
3473 // The remaining segments (the `C` in our example) will
3474 // have to be resolved by type-check, since that requires doing
3475 // trait resolution.
3476 return Some(PathResolution::with_unresolved_segments(
3477 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3481 let result = match self.resolve_path(
3489 PathResult::NonModule(path_res) => path_res,
3490 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3491 PathResolution::new(module.def().unwrap())
3493 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3494 // don't report an error right away, but try to fallback to a primitive type.
3495 // So, we are still able to successfully resolve something like
3497 // use std::u8; // bring module u8 in scope
3498 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3499 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3500 // // not to non-existent std::u8::max_value
3503 // Such behavior is required for backward compatibility.
3504 // The same fallback is used when `a` resolves to nothing.
3505 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3506 PathResult::Failed(..)
3507 if (ns == TypeNS || path.len() > 1) &&
3508 self.primitive_type_table.primitive_types
3509 .contains_key(&path[0].name) => {
3510 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3511 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3513 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3514 PathResolution::new(module.def().unwrap()),
3515 PathResult::Failed(span, msg, false) => {
3516 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3517 err_path_resolution()
3519 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3520 PathResult::Failed(..) => return None,
3521 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3524 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3525 path[0].name != keywords::CrateRoot.name() &&
3526 path[0].name != keywords::DollarCrate.name() {
3527 let unqualified_result = {
3528 match self.resolve_path(
3530 &[*path.last().unwrap()],
3536 PathResult::NonModule(path_res) => path_res.base_def(),
3537 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3538 module.def().unwrap(),
3539 _ => return Some(result),
3542 if result.base_def() == unqualified_result {
3543 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3544 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3553 base_module: Option<ModuleOrUniformRoot<'a>>,
3555 opt_ns: Option<Namespace>, // `None` indicates a module path
3558 crate_lint: CrateLint,
3559 ) -> PathResult<'a> {
3560 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3561 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3562 record_used, path_span, crate_lint)
3565 fn resolve_path_with_parent_scope(
3567 base_module: Option<ModuleOrUniformRoot<'a>>,
3569 opt_ns: Option<Namespace>, // `None` indicates a module path
3570 parent_scope: &ParentScope<'a>,
3573 crate_lint: CrateLint,
3574 ) -> PathResult<'a> {
3575 let mut module = base_module;
3576 let mut allow_super = true;
3577 let mut second_binding = None;
3578 self.current_module = parent_scope.module;
3581 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3582 path_span={:?}, crate_lint={:?})",
3590 for (i, &ident) in path.iter().enumerate() {
3591 debug!("resolve_path ident {} {:?}", i, ident);
3592 let is_last = i == path.len() - 1;
3593 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3594 let name = ident.name;
3596 allow_super &= ns == TypeNS &&
3597 (name == keywords::SelfValue.name() ||
3598 name == keywords::Super.name());
3601 if allow_super && name == keywords::Super.name() {
3602 let mut ctxt = ident.span.ctxt().modern();
3603 let self_module = match i {
3604 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3606 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3610 if let Some(self_module) = self_module {
3611 if let Some(parent) = self_module.parent {
3612 module = Some(ModuleOrUniformRoot::Module(
3613 self.resolve_self(&mut ctxt, parent)));
3617 let msg = "There are too many initial `super`s.".to_string();
3618 return PathResult::Failed(ident.span, msg, false);
3621 if name == keywords::SelfValue.name() {
3622 let mut ctxt = ident.span.ctxt().modern();
3623 module = Some(ModuleOrUniformRoot::Module(
3624 self.resolve_self(&mut ctxt, self.current_module)));
3627 if name == keywords::Extern.name() ||
3628 name == keywords::CrateRoot.name() &&
3629 self.session.rust_2018() {
3630 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3633 if name == keywords::CrateRoot.name() ||
3634 name == keywords::Crate.name() ||
3635 name == keywords::DollarCrate.name() {
3636 // `::a::b`, `crate::a::b` or `$crate::a::b`
3637 module = Some(ModuleOrUniformRoot::Module(
3638 self.resolve_crate_root(ident)));
3644 // Report special messages for path segment keywords in wrong positions.
3645 if ident.is_path_segment_keyword() && i != 0 {
3646 let name_str = if name == keywords::CrateRoot.name() {
3647 "crate root".to_string()
3649 format!("`{}`", name)
3651 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3652 format!("global paths cannot start with {}", name_str)
3654 format!("{} in paths can only be used in start position", name_str)
3656 return PathResult::Failed(ident.span, msg, false);
3659 let binding = if let Some(module) = module {
3660 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3661 } else if opt_ns == Some(MacroNS) {
3662 assert!(ns == TypeNS);
3663 self.early_resolve_ident_in_lexical_scope(ident, ns, None, parent_scope,
3664 record_used, record_used, path_span)
3666 let record_used_id =
3667 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3668 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3669 // we found a locally-imported or available item/module
3670 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3671 // we found a local variable or type param
3672 Some(LexicalScopeBinding::Def(def))
3673 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3674 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3678 _ => Err(if record_used { Determined } else { Undetermined }),
3685 second_binding = Some(binding);
3687 let def = binding.def();
3688 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3689 if let Some(next_module) = binding.module() {
3690 module = Some(ModuleOrUniformRoot::Module(next_module));
3691 } else if def == Def::ToolMod && i + 1 != path.len() {
3692 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3693 return PathResult::NonModule(PathResolution::new(def));
3694 } else if def == Def::Err {
3695 return PathResult::NonModule(err_path_resolution());
3696 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3697 self.lint_if_path_starts_with_module(
3703 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3704 def, path.len() - i - 1
3707 return PathResult::Failed(ident.span,
3708 format!("Not a module `{}`", ident),
3712 Err(Undetermined) => return PathResult::Indeterminate,
3713 Err(Determined) => {
3714 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3715 if opt_ns.is_some() && !module.is_normal() {
3716 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3717 module.def().unwrap(), path.len() - i
3721 let module_def = match module {
3722 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3725 let msg = if module_def == self.graph_root.def() {
3726 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3727 let mut candidates =
3728 self.lookup_import_candidates(name, TypeNS, is_mod);
3729 candidates.sort_by_cached_key(|c| {
3730 (c.path.segments.len(), c.path.to_string())
3732 if let Some(candidate) = candidates.get(0) {
3733 format!("Did you mean `{}`?", candidate.path)
3735 format!("Maybe a missing `extern crate {};`?", ident)
3738 format!("Use of undeclared type or module `{}`", ident)
3740 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3742 return PathResult::Failed(ident.span, msg, is_last);
3747 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3749 PathResult::Module(module.unwrap_or_else(|| {
3750 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3755 fn lint_if_path_starts_with_module(
3757 crate_lint: CrateLint,
3760 second_binding: Option<&NameBinding>,
3762 // In the 2018 edition this lint is a hard error, so nothing to do
3763 if self.session.rust_2018() {
3767 let (diag_id, diag_span) = match crate_lint {
3768 CrateLint::No => return,
3769 CrateLint::SimplePath(id) => (id, path_span),
3770 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3771 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3774 let first_name = match path.get(0) {
3775 Some(ident) => ident.name,
3779 // We're only interested in `use` paths which should start with
3780 // `{{root}}` or `extern` currently.
3781 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3786 // If this import looks like `crate::...` it's already good
3787 Some(ident) if ident.name == keywords::Crate.name() => return,
3788 // Otherwise go below to see if it's an extern crate
3790 // If the path has length one (and it's `CrateRoot` most likely)
3791 // then we don't know whether we're gonna be importing a crate or an
3792 // item in our crate. Defer this lint to elsewhere
3796 // If the first element of our path was actually resolved to an
3797 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3798 // warning, this looks all good!
3799 if let Some(binding) = second_binding {
3800 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3801 // Careful: we still want to rewrite paths from
3802 // renamed extern crates.
3803 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3809 let diag = lint::builtin::BuiltinLintDiagnostics
3810 ::AbsPathWithModule(diag_span);
3811 self.session.buffer_lint_with_diagnostic(
3812 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3814 "absolute paths must start with `self`, `super`, \
3815 `crate`, or an external crate name in the 2018 edition",
3819 // Resolve a local definition, potentially adjusting for closures.
3820 fn adjust_local_def(&mut self,
3825 span: Span) -> Def {
3826 let ribs = &self.ribs[ns][rib_index + 1..];
3828 // An invalid forward use of a type parameter from a previous default.
3829 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3831 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3833 assert_eq!(def, Def::Err);
3839 span_bug!(span, "unexpected {:?} in bindings", def)
3841 Def::Local(node_id) => {
3844 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3845 ForwardTyParamBanRibKind => {
3846 // Nothing to do. Continue.
3848 ClosureRibKind(function_id) => {
3851 let seen = self.freevars_seen
3854 if let Some(&index) = seen.get(&node_id) {
3855 def = Def::Upvar(node_id, index, function_id);
3858 let vec = self.freevars
3861 let depth = vec.len();
3862 def = Def::Upvar(node_id, depth, function_id);
3869 seen.insert(node_id, depth);
3872 ItemRibKind | TraitOrImplItemRibKind => {
3873 // This was an attempt to access an upvar inside a
3874 // named function item. This is not allowed, so we
3877 resolve_error(self, span,
3878 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3882 ConstantItemRibKind => {
3883 // Still doesn't deal with upvars
3885 resolve_error(self, span,
3886 ResolutionError::AttemptToUseNonConstantValueInConstant);
3893 Def::TyParam(..) | Def::SelfTy(..) => {
3896 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3897 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3898 ConstantItemRibKind => {
3899 // Nothing to do. Continue.
3902 // This was an attempt to use a type parameter outside
3905 resolve_error(self, span,
3906 ResolutionError::TypeParametersFromOuterFunction(def));
3918 fn lookup_assoc_candidate<FilterFn>(&mut self,
3921 filter_fn: FilterFn)
3922 -> Option<AssocSuggestion>
3923 where FilterFn: Fn(Def) -> bool
3925 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3927 TyKind::Path(None, _) => Some(t.id),
3928 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3929 // This doesn't handle the remaining `Ty` variants as they are not
3930 // that commonly the self_type, it might be interesting to provide
3931 // support for those in future.
3936 // Fields are generally expected in the same contexts as locals.
3937 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3938 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3939 // Look for a field with the same name in the current self_type.
3940 if let Some(resolution) = self.def_map.get(&node_id) {
3941 match resolution.base_def() {
3942 Def::Struct(did) | Def::Union(did)
3943 if resolution.unresolved_segments() == 0 => {
3944 if let Some(field_names) = self.field_names.get(&did) {
3945 if field_names.iter().any(|&field_name| ident.name == field_name) {
3946 return Some(AssocSuggestion::Field);
3956 // Look for associated items in the current trait.
3957 if let Some((module, _)) = self.current_trait_ref {
3958 if let Ok(binding) = self.resolve_ident_in_module(
3959 ModuleOrUniformRoot::Module(module),
3965 let def = binding.def();
3967 return Some(if self.has_self.contains(&def.def_id()) {
3968 AssocSuggestion::MethodWithSelf
3970 AssocSuggestion::AssocItem
3979 fn lookup_typo_candidate<FilterFn>(&mut self,
3982 filter_fn: FilterFn,
3985 where FilterFn: Fn(Def) -> bool
3987 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3988 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3989 if let Some(binding) = resolution.borrow().binding {
3990 if filter_fn(binding.def()) {
3991 names.push(ident.name);
3997 let mut names = Vec::new();
3998 if path.len() == 1 {
3999 // Search in lexical scope.
4000 // Walk backwards up the ribs in scope and collect candidates.
4001 for rib in self.ribs[ns].iter().rev() {
4002 // Locals and type parameters
4003 for (ident, def) in &rib.bindings {
4004 if filter_fn(*def) {
4005 names.push(ident.name);
4009 if let ModuleRibKind(module) = rib.kind {
4010 // Items from this module
4011 add_module_candidates(module, &mut names);
4013 if let ModuleKind::Block(..) = module.kind {
4014 // We can see through blocks
4016 // Items from the prelude
4017 if !module.no_implicit_prelude {
4018 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4019 if let Some(prelude) = self.prelude {
4020 add_module_candidates(prelude, &mut names);
4027 // Add primitive types to the mix
4028 if filter_fn(Def::PrimTy(Bool)) {
4030 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4034 // Search in module.
4035 let mod_path = &path[..path.len() - 1];
4036 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
4037 false, span, CrateLint::No) {
4038 if let ModuleOrUniformRoot::Module(module) = module {
4039 add_module_candidates(module, &mut names);
4044 let name = path[path.len() - 1].name;
4045 // Make sure error reporting is deterministic.
4046 names.sort_by_cached_key(|name| name.as_str());
4047 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4048 Some(found) if found != name => Some(found),
4053 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4054 where F: FnOnce(&mut Resolver)
4056 if let Some(label) = label {
4057 self.unused_labels.insert(id, label.ident.span);
4058 let def = Def::Label(id);
4059 self.with_label_rib(|this| {
4060 let ident = label.ident.modern_and_legacy();
4061 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4069 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4070 self.with_resolved_label(label, id, |this| this.visit_block(block));
4073 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4074 // First, record candidate traits for this expression if it could
4075 // result in the invocation of a method call.
4077 self.record_candidate_traits_for_expr_if_necessary(expr);
4079 // Next, resolve the node.
4081 ExprKind::Path(ref qself, ref path) => {
4082 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4083 visit::walk_expr(self, expr);
4086 ExprKind::Struct(ref path, ..) => {
4087 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4088 visit::walk_expr(self, expr);
4091 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4092 let def = self.search_label(label.ident, |rib, ident| {
4093 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4097 // Search again for close matches...
4098 // Picks the first label that is "close enough", which is not necessarily
4099 // the closest match
4100 let close_match = self.search_label(label.ident, |rib, ident| {
4101 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4102 find_best_match_for_name(names, &*ident.as_str(), None)
4104 self.record_def(expr.id, err_path_resolution());
4107 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4110 Some(Def::Label(id)) => {
4111 // Since this def is a label, it is never read.
4112 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4113 self.unused_labels.remove(&id);
4116 span_bug!(expr.span, "label wasn't mapped to a label def!");
4120 // visit `break` argument if any
4121 visit::walk_expr(self, expr);
4124 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4125 self.visit_expr(subexpression);
4127 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4128 let mut bindings_list = FxHashMap::default();
4130 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4132 // This has to happen *after* we determine which pat_idents are variants
4133 self.check_consistent_bindings(pats);
4134 self.visit_block(if_block);
4135 self.ribs[ValueNS].pop();
4137 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4140 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4142 ExprKind::While(ref subexpression, ref block, label) => {
4143 self.with_resolved_label(label, expr.id, |this| {
4144 this.visit_expr(subexpression);
4145 this.visit_block(block);
4149 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4150 self.with_resolved_label(label, expr.id, |this| {
4151 this.visit_expr(subexpression);
4152 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4153 let mut bindings_list = FxHashMap::default();
4155 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4157 // This has to happen *after* we determine which pat_idents are variants
4158 this.check_consistent_bindings(pats);
4159 this.visit_block(block);
4160 this.ribs[ValueNS].pop();
4164 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4165 self.visit_expr(subexpression);
4166 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4167 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4169 self.resolve_labeled_block(label, expr.id, block);
4171 self.ribs[ValueNS].pop();
4174 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4176 // Equivalent to `visit::walk_expr` + passing some context to children.
4177 ExprKind::Field(ref subexpression, _) => {
4178 self.resolve_expr(subexpression, Some(expr));
4180 ExprKind::MethodCall(ref segment, ref arguments) => {
4181 let mut arguments = arguments.iter();
4182 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4183 for argument in arguments {
4184 self.resolve_expr(argument, None);
4186 self.visit_path_segment(expr.span, segment);
4189 ExprKind::Call(ref callee, ref arguments) => {
4190 self.resolve_expr(callee, Some(expr));
4191 for argument in arguments {
4192 self.resolve_expr(argument, None);
4195 ExprKind::Type(ref type_expr, _) => {
4196 self.current_type_ascription.push(type_expr.span);
4197 visit::walk_expr(self, expr);
4198 self.current_type_ascription.pop();
4200 // Resolve the body of async exprs inside the async closure to which they desugar
4201 ExprKind::Async(_, async_closure_id, ref block) => {
4202 let rib_kind = ClosureRibKind(async_closure_id);
4203 self.ribs[ValueNS].push(Rib::new(rib_kind));
4204 self.label_ribs.push(Rib::new(rib_kind));
4205 self.visit_block(&block);
4206 self.label_ribs.pop();
4207 self.ribs[ValueNS].pop();
4209 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4210 // resolve the arguments within the proper scopes so that usages of them inside the
4211 // closure are detected as upvars rather than normal closure arg usages.
4213 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4214 ref fn_decl, ref body, _span,
4216 let rib_kind = ClosureRibKind(expr.id);
4217 self.ribs[ValueNS].push(Rib::new(rib_kind));
4218 self.label_ribs.push(Rib::new(rib_kind));
4219 // Resolve arguments:
4220 let mut bindings_list = FxHashMap::default();
4221 for argument in &fn_decl.inputs {
4222 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4223 self.visit_ty(&argument.ty);
4225 // No need to resolve return type-- the outer closure return type is
4226 // FunctionRetTy::Default
4228 // Now resolve the inner closure
4230 let rib_kind = ClosureRibKind(inner_closure_id);
4231 self.ribs[ValueNS].push(Rib::new(rib_kind));
4232 self.label_ribs.push(Rib::new(rib_kind));
4233 // No need to resolve arguments: the inner closure has none.
4234 // Resolve the return type:
4235 visit::walk_fn_ret_ty(self, &fn_decl.output);
4237 self.visit_expr(body);
4238 self.label_ribs.pop();
4239 self.ribs[ValueNS].pop();
4241 self.label_ribs.pop();
4242 self.ribs[ValueNS].pop();
4245 visit::walk_expr(self, expr);
4250 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4252 ExprKind::Field(_, ident) => {
4253 // FIXME(#6890): Even though you can't treat a method like a
4254 // field, we need to add any trait methods we find that match
4255 // the field name so that we can do some nice error reporting
4256 // later on in typeck.
4257 let traits = self.get_traits_containing_item(ident, ValueNS);
4258 self.trait_map.insert(expr.id, traits);
4260 ExprKind::MethodCall(ref segment, ..) => {
4261 debug!("(recording candidate traits for expr) recording traits for {}",
4263 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4264 self.trait_map.insert(expr.id, traits);
4272 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4273 -> Vec<TraitCandidate> {
4274 debug!("(getting traits containing item) looking for '{}'", ident.name);
4276 let mut found_traits = Vec::new();
4277 // Look for the current trait.
4278 if let Some((module, _)) = self.current_trait_ref {
4279 if self.resolve_ident_in_module(
4280 ModuleOrUniformRoot::Module(module),
4286 let def_id = module.def_id().unwrap();
4287 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4291 ident.span = ident.span.modern();
4292 let mut search_module = self.current_module;
4294 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4295 search_module = unwrap_or!(
4296 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4300 if let Some(prelude) = self.prelude {
4301 if !search_module.no_implicit_prelude {
4302 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4309 fn get_traits_in_module_containing_item(&mut self,
4313 found_traits: &mut Vec<TraitCandidate>) {
4314 assert!(ns == TypeNS || ns == ValueNS);
4315 let mut traits = module.traits.borrow_mut();
4316 if traits.is_none() {
4317 let mut collected_traits = Vec::new();
4318 module.for_each_child(|name, ns, binding| {
4319 if ns != TypeNS { return }
4320 if let Def::Trait(_) = binding.def() {
4321 collected_traits.push((name, binding));
4324 *traits = Some(collected_traits.into_boxed_slice());
4327 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4328 let module = binding.module().unwrap();
4329 let mut ident = ident;
4330 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4333 if self.resolve_ident_in_module_unadjusted(
4334 ModuleOrUniformRoot::Module(module),
4341 let import_id = match binding.kind {
4342 NameBindingKind::Import { directive, .. } => {
4343 self.maybe_unused_trait_imports.insert(directive.id);
4344 self.add_to_glob_map(directive.id, trait_name);
4349 let trait_def_id = module.def_id().unwrap();
4350 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4355 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4357 namespace: Namespace,
4358 start_module: &'a ModuleData<'a>,
4360 filter_fn: FilterFn)
4361 -> Vec<ImportSuggestion>
4362 where FilterFn: Fn(Def) -> bool
4364 let mut candidates = Vec::new();
4365 let mut seen_modules = FxHashSet::default();
4366 let not_local_module = crate_name != keywords::Crate.ident();
4367 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4369 while let Some((in_module,
4371 in_module_is_extern)) = worklist.pop() {
4372 self.populate_module_if_necessary(in_module);
4374 // We have to visit module children in deterministic order to avoid
4375 // instabilities in reported imports (#43552).
4376 in_module.for_each_child_stable(|ident, ns, name_binding| {
4377 // avoid imports entirely
4378 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4379 // avoid non-importable candidates as well
4380 if !name_binding.is_importable() { return; }
4382 // collect results based on the filter function
4383 if ident.name == lookup_name && ns == namespace {
4384 if filter_fn(name_binding.def()) {
4386 let mut segms = path_segments.clone();
4387 if self.session.rust_2018() {
4388 // crate-local absolute paths start with `crate::` in edition 2018
4389 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4391 0, ast::PathSegment::from_ident(crate_name)
4395 segms.push(ast::PathSegment::from_ident(ident));
4397 span: name_binding.span,
4400 // the entity is accessible in the following cases:
4401 // 1. if it's defined in the same crate, it's always
4402 // accessible (since private entities can be made public)
4403 // 2. if it's defined in another crate, it's accessible
4404 // only if both the module is public and the entity is
4405 // declared as public (due to pruning, we don't explore
4406 // outside crate private modules => no need to check this)
4407 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4408 candidates.push(ImportSuggestion { path: path });
4413 // collect submodules to explore
4414 if let Some(module) = name_binding.module() {
4416 let mut path_segments = path_segments.clone();
4417 path_segments.push(ast::PathSegment::from_ident(ident));
4419 let is_extern_crate_that_also_appears_in_prelude =
4420 name_binding.is_extern_crate() &&
4421 self.session.rust_2018();
4423 let is_visible_to_user =
4424 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4426 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4427 // add the module to the lookup
4428 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4429 if seen_modules.insert(module.def_id().unwrap()) {
4430 worklist.push((module, path_segments, is_extern));
4440 /// When name resolution fails, this method can be used to look up candidate
4441 /// entities with the expected name. It allows filtering them using the
4442 /// supplied predicate (which should be used to only accept the types of
4443 /// definitions expected e.g. traits). The lookup spans across all crates.
4445 /// NOTE: The method does not look into imports, but this is not a problem,
4446 /// since we report the definitions (thus, the de-aliased imports).
4447 fn lookup_import_candidates<FilterFn>(&mut self,
4449 namespace: Namespace,
4450 filter_fn: FilterFn)
4451 -> Vec<ImportSuggestion>
4452 where FilterFn: Fn(Def) -> bool
4454 let mut suggestions = self.lookup_import_candidates_from_module(
4455 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4457 if self.session.rust_2018() {
4458 let extern_prelude_names = self.extern_prelude.clone();
4459 for (ident, _) in extern_prelude_names.into_iter() {
4460 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4462 let crate_root = self.get_module(DefId {
4464 index: CRATE_DEF_INDEX,
4466 self.populate_module_if_necessary(&crate_root);
4468 suggestions.extend(self.lookup_import_candidates_from_module(
4469 lookup_name, namespace, crate_root, ident, &filter_fn));
4477 fn find_module(&mut self,
4479 -> Option<(Module<'a>, ImportSuggestion)>
4481 let mut result = None;
4482 let mut seen_modules = FxHashSet::default();
4483 let mut worklist = vec![(self.graph_root, Vec::new())];
4485 while let Some((in_module, path_segments)) = worklist.pop() {
4486 // abort if the module is already found
4487 if result.is_some() { break; }
4489 self.populate_module_if_necessary(in_module);
4491 in_module.for_each_child_stable(|ident, _, name_binding| {
4492 // abort if the module is already found or if name_binding is private external
4493 if result.is_some() || !name_binding.vis.is_visible_locally() {
4496 if let Some(module) = name_binding.module() {
4498 let mut path_segments = path_segments.clone();
4499 path_segments.push(ast::PathSegment::from_ident(ident));
4500 if module.def() == Some(module_def) {
4502 span: name_binding.span,
4503 segments: path_segments,
4505 result = Some((module, ImportSuggestion { path: path }));
4507 // add the module to the lookup
4508 if seen_modules.insert(module.def_id().unwrap()) {
4509 worklist.push((module, path_segments));
4519 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4520 if let Def::Enum(..) = enum_def {} else {
4521 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4524 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4525 self.populate_module_if_necessary(enum_module);
4527 let mut variants = Vec::new();
4528 enum_module.for_each_child_stable(|ident, _, name_binding| {
4529 if let Def::Variant(..) = name_binding.def() {
4530 let mut segms = enum_import_suggestion.path.segments.clone();
4531 segms.push(ast::PathSegment::from_ident(ident));
4532 variants.push(Path {
4533 span: name_binding.span,
4542 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4543 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4544 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4545 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4549 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4551 ast::VisibilityKind::Public => ty::Visibility::Public,
4552 ast::VisibilityKind::Crate(..) => {
4553 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4555 ast::VisibilityKind::Inherited => {
4556 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4558 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4559 // Visibilities are resolved as global by default, add starting root segment.
4560 let segments = path.make_root().iter().chain(path.segments.iter())
4561 .map(|seg| seg.ident)
4562 .collect::<Vec<_>>();
4563 let def = self.smart_resolve_path_fragment(
4568 PathSource::Visibility,
4569 CrateLint::SimplePath(id),
4571 if def == Def::Err {
4572 ty::Visibility::Public
4574 let vis = ty::Visibility::Restricted(def.def_id());
4575 if self.is_accessible(vis) {
4578 self.session.span_err(path.span, "visibilities can only be restricted \
4579 to ancestor modules");
4580 ty::Visibility::Public
4587 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4588 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4591 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4592 vis.is_accessible_from(module.normal_ancestor_id, self)
4595 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4596 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4597 if !ptr::eq(module, old_module) {
4598 span_bug!(binding.span, "parent module is reset for binding");
4603 fn disambiguate_legacy_vs_modern(
4605 legacy: &'a NameBinding<'a>,
4606 modern: &'a NameBinding<'a>,
4608 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4609 // is disambiguated to mitigate regressions from macro modularization.
4610 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4611 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4612 self.binding_parent_modules.get(&PtrKey(modern))) {
4613 (Some(legacy), Some(modern)) =>
4614 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4615 modern.is_ancestor_of(legacy),
4620 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4621 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4623 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4625 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4626 let note = if b1.expansion != Mark::root() {
4627 Some(if let Def::Macro(..) = b1.def() {
4628 format!("macro-expanded {} do not shadow",
4629 if b1.is_import() { "macro imports" } else { "macros" })
4631 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4632 if b1.is_import() { "imports" } else { "items" })
4634 } else if b1.is_glob_import() {
4635 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4640 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4641 err.span_label(ident.span, "ambiguous name");
4642 err.span_note(b1.span, &msg1);
4644 Def::Macro(..) if b2.span.is_dummy() =>
4645 err.note(&format!("`{}` is also a builtin macro", ident)),
4646 _ => err.span_note(b2.span, &msg2),
4648 if let Some(note) = note {
4654 fn report_errors(&mut self, krate: &Crate) {
4655 self.report_with_use_injections(krate);
4656 let mut reported_spans = FxHashSet::default();
4658 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4659 let msg = "macro-expanded `macro_export` macros from the current crate \
4660 cannot be referred to by absolute paths";
4661 self.session.buffer_lint_with_diagnostic(
4662 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4663 CRATE_NODE_ID, span_use, msg,
4664 lint::builtin::BuiltinLintDiagnostics::
4665 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4669 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4670 if reported_spans.insert(ident.span) {
4671 self.report_ambiguity_error(ident, b1, b2);
4675 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4676 if !reported_spans.insert(span) { continue }
4677 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4681 fn report_with_use_injections(&mut self, krate: &Crate) {
4682 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4683 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4684 if !candidates.is_empty() {
4685 show_candidates(&mut err, span, &candidates, better, found_use);
4691 fn report_conflict<'b>(&mut self,
4695 new_binding: &NameBinding<'b>,
4696 old_binding: &NameBinding<'b>) {
4697 // Error on the second of two conflicting names
4698 if old_binding.span.lo() > new_binding.span.lo() {
4699 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4702 let container = match parent.kind {
4703 ModuleKind::Def(Def::Mod(_), _) => "module",
4704 ModuleKind::Def(Def::Trait(_), _) => "trait",
4705 ModuleKind::Block(..) => "block",
4709 let old_noun = match old_binding.is_import() {
4711 false => "definition",
4714 let new_participle = match new_binding.is_import() {
4719 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4721 if let Some(s) = self.name_already_seen.get(&name) {
4727 let old_kind = match (ns, old_binding.module()) {
4728 (ValueNS, _) => "value",
4729 (MacroNS, _) => "macro",
4730 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4731 (TypeNS, Some(module)) if module.is_normal() => "module",
4732 (TypeNS, Some(module)) if module.is_trait() => "trait",
4733 (TypeNS, _) => "type",
4736 let msg = format!("the name `{}` is defined multiple times", name);
4738 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4739 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4740 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4741 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4742 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4744 _ => match (old_binding.is_import(), new_binding.is_import()) {
4745 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4746 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4747 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4751 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4756 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4757 if !old_binding.span.is_dummy() {
4758 err.span_label(self.session.source_map().def_span(old_binding.span),
4759 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4762 // See https://github.com/rust-lang/rust/issues/32354
4763 if old_binding.is_import() || new_binding.is_import() {
4764 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4770 let cm = self.session.source_map();
4771 let rename_msg = "you can use `as` to change the binding name of the import";
4775 NameBindingKind::Import { directive, ..},
4778 cm.span_to_snippet(binding.span),
4779 binding.kind.clone(),
4780 binding.span.is_dummy(),
4782 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4783 format!("Other{}", name)
4785 format!("other_{}", name)
4788 err.span_suggestion_with_applicability(
4791 match (&directive.subclass, snippet.as_ref()) {
4792 (ImportDirectiveSubclass::SingleImport { .. }, "self") =>
4793 format!("self as {}", suggested_name),
4794 (ImportDirectiveSubclass::SingleImport { source, .. }, _) =>
4797 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
4799 if snippet.ends_with(";") {
4805 (ImportDirectiveSubclass::ExternCrate { source, target, .. }, _) =>
4807 "extern crate {} as {};",
4808 source.unwrap_or(target.name),
4811 (_, _) => unreachable!(),
4813 Applicability::MaybeIncorrect,
4816 err.span_label(binding.span, rename_msg);
4821 self.name_already_seen.insert(name, span);
4824 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool, skip_feature_gate: bool)
4825 -> Option<&'a NameBinding<'a>> {
4826 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
4827 if let Some(binding) = entry.extern_crate_item {
4828 if !speculative && !skip_feature_gate && entry.introduced_by_item &&
4829 !self.session.features_untracked().extern_crate_item_prelude {
4830 emit_feature_err(&self.session.parse_sess, "extern_crate_item_prelude",
4831 ident.span, GateIssue::Language,
4832 "use of extern prelude names introduced \
4833 with `extern crate` items is unstable");
4837 let crate_id = if !speculative {
4838 self.crate_loader.process_path_extern(ident.name, ident.span)
4839 } else if let Some(crate_id) =
4840 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
4845 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
4846 self.populate_module_if_necessary(&crate_root);
4847 Some((crate_root, ty::Visibility::Public, ident.span, Mark::root())
4848 .to_name_binding(self.arenas))
4854 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4855 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4858 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4859 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4862 fn names_to_string(idents: &[Ident]) -> String {
4863 let mut result = String::new();
4864 for (i, ident) in idents.iter()
4865 .filter(|ident| ident.name != keywords::CrateRoot.name())
4868 result.push_str("::");
4870 result.push_str(&ident.as_str());
4875 fn path_names_to_string(path: &Path) -> String {
4876 names_to_string(&path.segments.iter()
4877 .map(|seg| seg.ident)
4878 .collect::<Vec<_>>())
4881 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4882 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4883 let variant_path = &suggestion.path;
4884 let variant_path_string = path_names_to_string(variant_path);
4886 let path_len = suggestion.path.segments.len();
4887 let enum_path = ast::Path {
4888 span: suggestion.path.span,
4889 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4891 let enum_path_string = path_names_to_string(&enum_path);
4893 (suggestion.path.span, variant_path_string, enum_path_string)
4897 /// When an entity with a given name is not available in scope, we search for
4898 /// entities with that name in all crates. This method allows outputting the
4899 /// results of this search in a programmer-friendly way
4900 fn show_candidates(err: &mut DiagnosticBuilder,
4901 // This is `None` if all placement locations are inside expansions
4903 candidates: &[ImportSuggestion],
4907 // we want consistent results across executions, but candidates are produced
4908 // by iterating through a hash map, so make sure they are ordered:
4909 let mut path_strings: Vec<_> =
4910 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4911 path_strings.sort();
4913 let better = if better { "better " } else { "" };
4914 let msg_diff = match path_strings.len() {
4915 1 => " is found in another module, you can import it",
4916 _ => "s are found in other modules, you can import them",
4918 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4920 if let Some(span) = span {
4921 for candidate in &mut path_strings {
4922 // produce an additional newline to separate the new use statement
4923 // from the directly following item.
4924 let additional_newline = if found_use {
4929 *candidate = format!("use {};\n{}", candidate, additional_newline);
4932 err.span_suggestions_with_applicability(
4936 Applicability::Unspecified,
4941 for candidate in path_strings {
4943 msg.push_str(&candidate);
4948 /// A somewhat inefficient routine to obtain the name of a module.
4949 fn module_to_string(module: Module) -> Option<String> {
4950 let mut names = Vec::new();
4952 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4953 if let ModuleKind::Def(_, name) = module.kind {
4954 if let Some(parent) = module.parent {
4955 names.push(Ident::with_empty_ctxt(name));
4956 collect_mod(names, parent);
4959 // danger, shouldn't be ident?
4960 names.push(Ident::from_str("<opaque>"));
4961 collect_mod(names, module.parent.unwrap());
4964 collect_mod(&mut names, module);
4966 if names.is_empty() {
4969 Some(names_to_string(&names.into_iter()
4971 .collect::<Vec<_>>()))
4974 fn err_path_resolution() -> PathResolution {
4975 PathResolution::new(Def::Err)
4978 #[derive(PartialEq,Copy, Clone)]
4979 pub enum MakeGlobMap {
4984 #[derive(Copy, Clone, Debug)]
4986 /// Do not issue the lint
4989 /// This lint applies to some random path like `impl ::foo::Bar`
4990 /// or whatever. In this case, we can take the span of that path.
4993 /// This lint comes from a `use` statement. In this case, what we
4994 /// care about really is the *root* `use` statement; e.g., if we
4995 /// have nested things like `use a::{b, c}`, we care about the
4997 UsePath { root_id: NodeId, root_span: Span },
4999 /// This is the "trait item" from a fully qualified path. For example,
5000 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5001 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5002 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5006 fn node_id(&self) -> Option<NodeId> {
5008 CrateLint::No => None,
5009 CrateLint::SimplePath(id) |
5010 CrateLint::UsePath { root_id: id, .. } |
5011 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5016 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }