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 // A minimal representation of a path segment. We use this in resolve because
636 // we synthesize 'path segments' which don't have the rest of an AST or HIR
638 #[derive(Clone, Copy, Debug)]
645 fn from_path(path: &Path) -> Vec<Segment> {
646 path.segments.iter().map(|s| s.into()).collect()
649 fn from_ident(ident: Ident) -> Segment {
656 fn names_to_string(segments: &[Segment]) -> String {
657 names_to_string(&segments.iter()
658 .map(|seg| seg.ident)
659 .collect::<Vec<_>>())
663 impl<'a> From<&'a ast::PathSegment> for Segment {
664 fn from(seg: &'a ast::PathSegment) -> Segment {
672 struct UsePlacementFinder {
673 target_module: NodeId,
678 impl UsePlacementFinder {
679 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
680 let mut finder = UsePlacementFinder {
685 visit::walk_crate(&mut finder, krate);
686 (finder.span, finder.found_use)
690 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
693 module: &'tcx ast::Mod,
695 _: &[ast::Attribute],
698 if self.span.is_some() {
701 if node_id != self.target_module {
702 visit::walk_mod(self, module);
705 // find a use statement
706 for item in &module.items {
708 ItemKind::Use(..) => {
709 // don't suggest placing a use before the prelude
710 // import or other generated ones
711 if item.span.ctxt().outer().expn_info().is_none() {
712 self.span = Some(item.span.shrink_to_lo());
713 self.found_use = true;
717 // don't place use before extern crate
718 ItemKind::ExternCrate(_) => {}
719 // but place them before the first other item
720 _ => if self.span.map_or(true, |span| item.span < span ) {
721 if item.span.ctxt().outer().expn_info().is_none() {
722 // don't insert between attributes and an item
723 if item.attrs.is_empty() {
724 self.span = Some(item.span.shrink_to_lo());
726 // find the first attribute on the item
727 for attr in &item.attrs {
728 if self.span.map_or(true, |span| attr.span < span) {
729 self.span = Some(attr.span.shrink_to_lo());
740 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
741 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
742 fn visit_item(&mut self, item: &'tcx Item) {
743 self.resolve_item(item);
745 fn visit_arm(&mut self, arm: &'tcx Arm) {
746 self.resolve_arm(arm);
748 fn visit_block(&mut self, block: &'tcx Block) {
749 self.resolve_block(block);
751 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
752 self.with_constant_rib(|this| {
753 visit::walk_anon_const(this, constant);
756 fn visit_expr(&mut self, expr: &'tcx Expr) {
757 self.resolve_expr(expr, None);
759 fn visit_local(&mut self, local: &'tcx Local) {
760 self.resolve_local(local);
762 fn visit_ty(&mut self, ty: &'tcx Ty) {
764 TyKind::Path(ref qself, ref path) => {
765 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
767 TyKind::ImplicitSelf => {
768 let self_ty = keywords::SelfType.ident();
769 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
770 .map_or(Def::Err, |d| d.def());
771 self.record_def(ty.id, PathResolution::new(def));
775 visit::walk_ty(self, ty);
777 fn visit_poly_trait_ref(&mut self,
778 tref: &'tcx ast::PolyTraitRef,
779 m: &'tcx ast::TraitBoundModifier) {
780 self.smart_resolve_path(tref.trait_ref.ref_id, None,
781 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
782 visit::walk_poly_trait_ref(self, tref, m);
784 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
785 let type_parameters = match foreign_item.node {
786 ForeignItemKind::Fn(_, ref generics) => {
787 HasTypeParameters(generics, ItemRibKind)
789 ForeignItemKind::Static(..) => NoTypeParameters,
790 ForeignItemKind::Ty => NoTypeParameters,
791 ForeignItemKind::Macro(..) => NoTypeParameters,
793 self.with_type_parameter_rib(type_parameters, |this| {
794 visit::walk_foreign_item(this, foreign_item);
797 fn visit_fn(&mut self,
798 function_kind: FnKind<'tcx>,
799 declaration: &'tcx FnDecl,
803 let (rib_kind, asyncness) = match function_kind {
804 FnKind::ItemFn(_, ref header, ..) =>
805 (ItemRibKind, header.asyncness),
806 FnKind::Method(_, ref sig, _, _) =>
807 (TraitOrImplItemRibKind, sig.header.asyncness),
808 FnKind::Closure(_) =>
809 // Async closures aren't resolved through `visit_fn`-- they're
810 // processed separately
811 (ClosureRibKind(node_id), IsAsync::NotAsync),
814 // Create a value rib for the function.
815 self.ribs[ValueNS].push(Rib::new(rib_kind));
817 // Create a label rib for the function.
818 self.label_ribs.push(Rib::new(rib_kind));
820 // Add each argument to the rib.
821 let mut bindings_list = FxHashMap::default();
822 for argument in &declaration.inputs {
823 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
825 self.visit_ty(&argument.ty);
827 debug!("(resolving function) recorded argument");
829 visit::walk_fn_ret_ty(self, &declaration.output);
831 // Resolve the function body, potentially inside the body of an async closure
832 if let IsAsync::Async { closure_id, .. } = asyncness {
833 let rib_kind = ClosureRibKind(closure_id);
834 self.ribs[ValueNS].push(Rib::new(rib_kind));
835 self.label_ribs.push(Rib::new(rib_kind));
838 match function_kind {
839 FnKind::ItemFn(.., body) |
840 FnKind::Method(.., body) => {
841 self.visit_block(body);
843 FnKind::Closure(body) => {
844 self.visit_expr(body);
848 // Leave the body of the async closure
849 if asyncness.is_async() {
850 self.label_ribs.pop();
851 self.ribs[ValueNS].pop();
854 debug!("(resolving function) leaving function");
856 self.label_ribs.pop();
857 self.ribs[ValueNS].pop();
859 fn visit_generics(&mut self, generics: &'tcx Generics) {
860 // For type parameter defaults, we have to ban access
861 // to following type parameters, as the Substs can only
862 // provide previous type parameters as they're built. We
863 // put all the parameters on the ban list and then remove
864 // them one by one as they are processed and become available.
865 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
866 let mut found_default = false;
867 default_ban_rib.bindings.extend(generics.params.iter()
868 .filter_map(|param| match param.kind {
869 GenericParamKind::Lifetime { .. } => None,
870 GenericParamKind::Type { ref default, .. } => {
871 found_default |= default.is_some();
873 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
880 for param in &generics.params {
882 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
883 GenericParamKind::Type { ref default, .. } => {
884 for bound in ¶m.bounds {
885 self.visit_param_bound(bound);
888 if let Some(ref ty) = default {
889 self.ribs[TypeNS].push(default_ban_rib);
891 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
894 // Allow all following defaults to refer to this type parameter.
895 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
899 for p in &generics.where_clause.predicates {
900 self.visit_where_predicate(p);
905 #[derive(Copy, Clone)]
906 enum TypeParameters<'a, 'b> {
908 HasTypeParameters(// Type parameters.
911 // The kind of the rib used for type parameters.
915 /// The rib kind controls the translation of local
916 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
917 #[derive(Copy, Clone, Debug)]
919 /// No translation needs to be applied.
922 /// We passed through a closure scope at the given node ID.
923 /// Translate upvars as appropriate.
924 ClosureRibKind(NodeId /* func id */),
926 /// We passed through an impl or trait and are now in one of its
927 /// methods or associated types. Allow references to ty params that impl or trait
928 /// binds. Disallow any other upvars (including other ty params that are
930 TraitOrImplItemRibKind,
932 /// We passed through an item scope. Disallow upvars.
935 /// We're in a constant item. Can't refer to dynamic stuff.
938 /// We passed through a module.
939 ModuleRibKind(Module<'a>),
941 /// We passed through a `macro_rules!` statement
942 MacroDefinition(DefId),
944 /// All bindings in this rib are type parameters that can't be used
945 /// from the default of a type parameter because they're not declared
946 /// before said type parameter. Also see the `visit_generics` override.
947 ForwardTyParamBanRibKind,
952 /// A rib represents a scope names can live in. Note that these appear in many places, not just
953 /// around braces. At any place where the list of accessible names (of the given namespace)
954 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
955 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
958 /// Different [rib kinds](enum.RibKind) are transparent for different names.
960 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
961 /// resolving, the name is looked up from inside out.
964 bindings: FxHashMap<Ident, Def>,
969 fn new(kind: RibKind<'a>) -> Rib<'a> {
971 bindings: Default::default(),
977 /// An intermediate resolution result.
979 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
980 /// items are visible in their whole block, while defs only from the place they are defined
982 enum LexicalScopeBinding<'a> {
983 Item(&'a NameBinding<'a>),
987 impl<'a> LexicalScopeBinding<'a> {
988 fn item(self) -> Option<&'a NameBinding<'a>> {
990 LexicalScopeBinding::Item(binding) => Some(binding),
995 fn def(self) -> Def {
997 LexicalScopeBinding::Item(binding) => binding.def(),
998 LexicalScopeBinding::Def(def) => def,
1003 #[derive(Copy, Clone, Debug)]
1004 pub enum ModuleOrUniformRoot<'a> {
1008 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
1009 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
1010 /// but *not* `extern`), in the Rust 2018 edition.
1014 #[derive(Clone, Debug)]
1015 enum PathResult<'a> {
1016 Module(ModuleOrUniformRoot<'a>),
1017 NonModule(PathResolution),
1019 Failed(Span, String, bool /* is the error from the last segment? */),
1023 /// An anonymous module, eg. just a block.
1027 /// fn f() {} // (1)
1028 /// { // This is an anonymous module
1029 /// f(); // This resolves to (2) as we are inside the block.
1030 /// fn f() {} // (2)
1032 /// f(); // Resolves to (1)
1036 /// Any module with a name.
1040 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1041 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1046 /// One node in the tree of modules.
1047 pub struct ModuleData<'a> {
1048 parent: Option<Module<'a>>,
1051 // The def id of the closest normal module (`mod`) ancestor (including this module).
1052 normal_ancestor_id: DefId,
1054 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1055 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1056 Option<&'a NameBinding<'a>>)>>,
1057 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1058 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1060 // Macro invocations that can expand into items in this module.
1061 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1063 no_implicit_prelude: bool,
1065 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1066 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1068 // Used to memoize the traits in this module for faster searches through all traits in scope.
1069 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1071 // Whether this module is populated. If not populated, any attempt to
1072 // access the children must be preceded with a
1073 // `populate_module_if_necessary` call.
1074 populated: Cell<bool>,
1076 /// Span of the module itself. Used for error reporting.
1082 type Module<'a> = &'a ModuleData<'a>;
1084 impl<'a> ModuleData<'a> {
1085 fn new(parent: Option<Module<'a>>,
1087 normal_ancestor_id: DefId,
1089 span: Span) -> Self {
1094 resolutions: Default::default(),
1095 legacy_macro_resolutions: RefCell::new(Vec::new()),
1096 macro_resolutions: RefCell::new(Vec::new()),
1097 builtin_attrs: RefCell::new(Vec::new()),
1098 unresolved_invocations: Default::default(),
1099 no_implicit_prelude: false,
1100 glob_importers: RefCell::new(Vec::new()),
1101 globs: RefCell::new(Vec::new()),
1102 traits: RefCell::new(None),
1103 populated: Cell::new(normal_ancestor_id.is_local()),
1109 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1110 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1111 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1115 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1116 let resolutions = self.resolutions.borrow();
1117 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1118 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1119 for &(&(ident, ns), &resolution) in resolutions.iter() {
1120 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1124 fn def(&self) -> Option<Def> {
1126 ModuleKind::Def(def, _) => Some(def),
1131 fn def_id(&self) -> Option<DefId> {
1132 self.def().as_ref().map(Def::def_id)
1135 // `self` resolves to the first module ancestor that `is_normal`.
1136 fn is_normal(&self) -> bool {
1138 ModuleKind::Def(Def::Mod(_), _) => true,
1143 fn is_trait(&self) -> bool {
1145 ModuleKind::Def(Def::Trait(_), _) => true,
1150 fn is_local(&self) -> bool {
1151 self.normal_ancestor_id.is_local()
1154 fn nearest_item_scope(&'a self) -> Module<'a> {
1155 if self.is_trait() { self.parent.unwrap() } else { self }
1158 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1159 while !ptr::eq(self, other) {
1160 if let Some(parent) = other.parent {
1170 impl<'a> fmt::Debug for ModuleData<'a> {
1171 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1172 write!(f, "{:?}", self.def())
1176 /// Records a possibly-private value, type, or module definition.
1177 #[derive(Clone, Debug)]
1178 pub struct NameBinding<'a> {
1179 kind: NameBindingKind<'a>,
1182 vis: ty::Visibility,
1185 pub trait ToNameBinding<'a> {
1186 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1189 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1190 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1195 #[derive(Clone, Debug)]
1196 enum NameBindingKind<'a> {
1197 Def(Def, /* is_macro_export */ bool),
1200 binding: &'a NameBinding<'a>,
1201 directive: &'a ImportDirective<'a>,
1205 b1: &'a NameBinding<'a>,
1206 b2: &'a NameBinding<'a>,
1210 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1212 struct UseError<'a> {
1213 err: DiagnosticBuilder<'a>,
1214 /// Attach `use` statements for these candidates
1215 candidates: Vec<ImportSuggestion>,
1216 /// The node id of the module to place the use statements in
1218 /// Whether the diagnostic should state that it's "better"
1222 struct AmbiguityError<'a> {
1224 b1: &'a NameBinding<'a>,
1225 b2: &'a NameBinding<'a>,
1228 impl<'a> NameBinding<'a> {
1229 fn module(&self) -> Option<Module<'a>> {
1231 NameBindingKind::Module(module) => Some(module),
1232 NameBindingKind::Import { binding, .. } => binding.module(),
1237 fn def(&self) -> Def {
1239 NameBindingKind::Def(def, _) => def,
1240 NameBindingKind::Module(module) => module.def().unwrap(),
1241 NameBindingKind::Import { binding, .. } => binding.def(),
1242 NameBindingKind::Ambiguity { .. } => Def::Err,
1246 fn def_ignoring_ambiguity(&self) -> Def {
1248 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1249 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1254 // We sometimes need to treat variants as `pub` for backwards compatibility
1255 fn pseudo_vis(&self) -> ty::Visibility {
1256 if self.is_variant() && self.def().def_id().is_local() {
1257 ty::Visibility::Public
1263 fn is_variant(&self) -> bool {
1265 NameBindingKind::Def(Def::Variant(..), _) |
1266 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1271 fn is_extern_crate(&self) -> bool {
1273 NameBindingKind::Import {
1274 directive: &ImportDirective {
1275 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1282 fn is_import(&self) -> bool {
1284 NameBindingKind::Import { .. } => true,
1289 fn is_glob_import(&self) -> bool {
1291 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1292 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1297 fn is_importable(&self) -> bool {
1299 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1304 fn is_macro_def(&self) -> bool {
1306 NameBindingKind::Def(Def::Macro(..), _) => true,
1311 fn macro_kind(&self) -> Option<MacroKind> {
1312 match self.def_ignoring_ambiguity() {
1313 Def::Macro(_, kind) => Some(kind),
1314 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1319 fn descr(&self) -> &'static str {
1320 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1323 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1324 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1325 // Then this function returns `true` if `self` may emerge from a macro *after* that
1326 // in some later round and screw up our previously found resolution.
1327 // See more detailed explanation in
1328 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1329 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1330 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1331 // Expansions are partially ordered, so "may appear after" is an inversion of
1332 // "certainly appears before or simultaneously" and includes unordered cases.
1333 let self_parent_expansion = self.expansion;
1334 let other_parent_expansion = binding.expansion;
1335 let certainly_before_other_or_simultaneously =
1336 other_parent_expansion.is_descendant_of(self_parent_expansion);
1337 let certainly_before_invoc_or_simultaneously =
1338 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1339 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1343 /// Interns the names of the primitive types.
1345 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1346 /// special handling, since they have no place of origin.
1348 struct PrimitiveTypeTable {
1349 primitive_types: FxHashMap<Name, PrimTy>,
1352 impl PrimitiveTypeTable {
1353 fn new() -> PrimitiveTypeTable {
1354 let mut table = PrimitiveTypeTable::default();
1356 table.intern("bool", Bool);
1357 table.intern("char", Char);
1358 table.intern("f32", Float(FloatTy::F32));
1359 table.intern("f64", Float(FloatTy::F64));
1360 table.intern("isize", Int(IntTy::Isize));
1361 table.intern("i8", Int(IntTy::I8));
1362 table.intern("i16", Int(IntTy::I16));
1363 table.intern("i32", Int(IntTy::I32));
1364 table.intern("i64", Int(IntTy::I64));
1365 table.intern("i128", Int(IntTy::I128));
1366 table.intern("str", Str);
1367 table.intern("usize", Uint(UintTy::Usize));
1368 table.intern("u8", Uint(UintTy::U8));
1369 table.intern("u16", Uint(UintTy::U16));
1370 table.intern("u32", Uint(UintTy::U32));
1371 table.intern("u64", Uint(UintTy::U64));
1372 table.intern("u128", Uint(UintTy::U128));
1376 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1377 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1381 #[derive(Default, Clone)]
1382 pub struct ExternPreludeEntry<'a> {
1383 extern_crate_item: Option<&'a NameBinding<'a>>,
1384 pub introduced_by_item: bool,
1387 /// The main resolver class.
1389 /// This is the visitor that walks the whole crate.
1390 pub struct Resolver<'a, 'b: 'a> {
1391 session: &'a Session,
1394 pub definitions: Definitions,
1396 graph_root: Module<'a>,
1398 prelude: Option<Module<'a>>,
1399 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1401 /// n.b. This is used only for better diagnostics, not name resolution itself.
1402 has_self: FxHashSet<DefId>,
1404 /// Names of fields of an item `DefId` accessible with dot syntax.
1405 /// Used for hints during error reporting.
1406 field_names: FxHashMap<DefId, Vec<Name>>,
1408 /// All imports known to succeed or fail.
1409 determined_imports: Vec<&'a ImportDirective<'a>>,
1411 /// All non-determined imports.
1412 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1414 /// The module that represents the current item scope.
1415 current_module: Module<'a>,
1417 /// The current set of local scopes for types and values.
1418 /// FIXME #4948: Reuse ribs to avoid allocation.
1419 ribs: PerNS<Vec<Rib<'a>>>,
1421 /// The current set of local scopes, for labels.
1422 label_ribs: Vec<Rib<'a>>,
1424 /// The trait that the current context can refer to.
1425 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1427 /// The current self type if inside an impl (used for better errors).
1428 current_self_type: Option<Ty>,
1430 /// The current self item if inside an ADT (used for better errors).
1431 current_self_item: Option<NodeId>,
1433 /// The idents for the primitive types.
1434 primitive_type_table: PrimitiveTypeTable,
1437 import_map: ImportMap,
1438 pub freevars: FreevarMap,
1439 freevars_seen: NodeMap<NodeMap<usize>>,
1440 pub export_map: ExportMap,
1441 pub trait_map: TraitMap,
1443 /// A map from nodes to anonymous modules.
1444 /// Anonymous modules are pseudo-modules that are implicitly created around items
1445 /// contained within blocks.
1447 /// For example, if we have this:
1455 /// There will be an anonymous module created around `g` with the ID of the
1456 /// entry block for `f`.
1457 block_map: NodeMap<Module<'a>>,
1458 module_map: FxHashMap<DefId, Module<'a>>,
1459 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1460 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1462 pub make_glob_map: bool,
1463 /// Maps imports to the names of items actually imported (this actually maps
1464 /// all imports, but only glob imports are actually interesting).
1465 pub glob_map: GlobMap,
1467 used_imports: FxHashSet<(NodeId, Namespace)>,
1468 pub maybe_unused_trait_imports: NodeSet,
1469 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1471 /// A list of labels as of yet unused. Labels will be removed from this map when
1472 /// they are used (in a `break` or `continue` statement)
1473 pub unused_labels: FxHashMap<NodeId, Span>,
1475 /// privacy errors are delayed until the end in order to deduplicate them
1476 privacy_errors: Vec<PrivacyError<'a>>,
1477 /// ambiguity errors are delayed for deduplication
1478 ambiguity_errors: Vec<AmbiguityError<'a>>,
1479 /// `use` injections are delayed for better placement and deduplication
1480 use_injections: Vec<UseError<'a>>,
1481 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1482 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1484 arenas: &'a ResolverArenas<'a>,
1485 dummy_binding: &'a NameBinding<'a>,
1487 crate_loader: &'a mut CrateLoader<'b>,
1488 macro_names: FxHashSet<Ident>,
1489 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1490 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1491 pub all_macros: FxHashMap<Name, Def>,
1492 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1493 macro_defs: FxHashMap<Mark, DefId>,
1494 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1495 pub whitelisted_legacy_custom_derives: Vec<Name>,
1496 pub found_unresolved_macro: bool,
1498 /// List of crate local macros that we need to warn about as being unused.
1499 /// Right now this only includes macro_rules! macros, and macros 2.0.
1500 unused_macros: FxHashSet<DefId>,
1502 /// Maps the `Mark` of an expansion to its containing module or block.
1503 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1505 /// Avoid duplicated errors for "name already defined".
1506 name_already_seen: FxHashMap<Name, Span>,
1508 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1510 /// This table maps struct IDs into struct constructor IDs,
1511 /// it's not used during normal resolution, only for better error reporting.
1512 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1514 /// Only used for better errors on `fn(): fn()`
1515 current_type_ascription: Vec<Span>,
1517 injected_crate: Option<Module<'a>>,
1520 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1522 pub struct ResolverArenas<'a> {
1523 modules: arena::TypedArena<ModuleData<'a>>,
1524 local_modules: RefCell<Vec<Module<'a>>>,
1525 name_bindings: arena::TypedArena<NameBinding<'a>>,
1526 import_directives: arena::TypedArena<ImportDirective<'a>>,
1527 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1528 invocation_data: arena::TypedArena<InvocationData<'a>>,
1529 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1532 impl<'a> ResolverArenas<'a> {
1533 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1534 let module = self.modules.alloc(module);
1535 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1536 self.local_modules.borrow_mut().push(module);
1540 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1541 self.local_modules.borrow()
1543 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1544 self.name_bindings.alloc(name_binding)
1546 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1547 -> &'a ImportDirective {
1548 self.import_directives.alloc(import_directive)
1550 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1551 self.name_resolutions.alloc(Default::default())
1553 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1554 -> &'a InvocationData<'a> {
1555 self.invocation_data.alloc(expansion_data)
1557 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1558 self.legacy_bindings.alloc(binding)
1562 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1563 fn parent(self, id: DefId) -> Option<DefId> {
1565 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1566 _ => self.cstore.def_key(id).parent,
1567 }.map(|index| DefId { index, ..id })
1571 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1572 /// the resolver is no longer needed as all the relevant information is inline.
1573 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1574 fn resolve_hir_path(
1577 args: Option<P<hir::GenericArgs>>,
1580 self.resolve_hir_path_cb(path, args, is_value,
1581 |resolver, span, error| resolve_error(resolver, span, error))
1584 fn resolve_str_path(
1587 crate_root: Option<&str>,
1588 components: &[&str],
1589 args: Option<P<hir::GenericArgs>>,
1592 let segments = iter::once(keywords::CrateRoot.ident())
1594 crate_root.into_iter()
1595 .chain(components.iter().cloned())
1596 .map(Ident::from_str)
1597 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1600 let path = ast::Path {
1605 self.resolve_hir_path(&path, args, is_value)
1608 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1609 self.def_map.get(&id).cloned()
1612 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1613 self.import_map.get(&id).cloned().unwrap_or_default()
1616 fn definitions(&mut self) -> &mut Definitions {
1617 &mut self.definitions
1621 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1622 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1623 /// isn't something that can be returned because it can't be made to live that long,
1624 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1625 /// just that an error occurred.
1626 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1627 -> Result<hir::Path, ()> {
1629 let mut errored = false;
1631 let path = if path_str.starts_with("::") {
1634 segments: iter::once(keywords::CrateRoot.ident())
1636 path_str.split("::").skip(1).map(Ident::from_str)
1638 .map(|i| self.new_ast_path_segment(i))
1646 .map(Ident::from_str)
1647 .map(|i| self.new_ast_path_segment(i))
1651 let path = self.resolve_hir_path_cb(&path, None, is_value, |_, _, _| errored = true);
1652 if errored || path.def == Def::Err {
1659 /// resolve_hir_path, but takes a callback in case there was an error
1660 fn resolve_hir_path_cb<F>(
1663 args: Option<P<hir::GenericArgs>>,
1667 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1669 let namespace = if is_value { ValueNS } else { TypeNS };
1670 let span = path.span;
1671 let segments = &path.segments;
1672 let path = Segment::from_path(&path);
1673 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1674 let def = match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1675 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1676 module.def().unwrap(),
1677 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1678 *def = path_res.base_def(),
1679 PathResult::NonModule(..) =>
1680 if let PathResult::Failed(span, msg, _) = self.resolve_path(
1688 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1690 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1691 PathResult::Indeterminate => unreachable!(),
1692 PathResult::Failed(span, msg, _) => {
1693 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1698 let mut segments: Vec<_> = segments.iter().map(|seg| {
1699 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1700 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1703 segments.last_mut().unwrap().args = args;
1707 segments: segments.into(),
1711 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1712 let mut seg = ast::PathSegment::from_ident(ident);
1713 seg.id = self.session.next_node_id();
1718 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1719 pub fn new(session: &'a Session,
1723 make_glob_map: MakeGlobMap,
1724 crate_loader: &'a mut CrateLoader<'crateloader>,
1725 arenas: &'a ResolverArenas<'a>)
1726 -> Resolver<'a, 'crateloader> {
1727 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1728 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1729 let graph_root = arenas.alloc_module(ModuleData {
1730 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1731 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1733 let mut module_map = FxHashMap::default();
1734 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1736 let mut definitions = Definitions::new();
1737 DefCollector::new(&mut definitions, Mark::root())
1738 .collect_root(crate_name, session.local_crate_disambiguator());
1740 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1741 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1744 if !attr::contains_name(&krate.attrs, "no_core") {
1745 extern_prelude.insert(Ident::from_str("core"), Default::default());
1746 if !attr::contains_name(&krate.attrs, "no_std") {
1747 extern_prelude.insert(Ident::from_str("std"), Default::default());
1748 if session.rust_2018() {
1749 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1754 let mut invocations = FxHashMap::default();
1755 invocations.insert(Mark::root(),
1756 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1758 let mut macro_defs = FxHashMap::default();
1759 macro_defs.insert(Mark::root(), root_def_id);
1768 // The outermost module has def ID 0; this is not reflected in the
1774 has_self: FxHashSet::default(),
1775 field_names: FxHashMap::default(),
1777 determined_imports: Vec::new(),
1778 indeterminate_imports: Vec::new(),
1780 current_module: graph_root,
1782 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1783 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1784 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1786 label_ribs: Vec::new(),
1788 current_trait_ref: None,
1789 current_self_type: None,
1790 current_self_item: None,
1792 primitive_type_table: PrimitiveTypeTable::new(),
1795 import_map: NodeMap(),
1796 freevars: NodeMap(),
1797 freevars_seen: NodeMap(),
1798 export_map: FxHashMap::default(),
1799 trait_map: NodeMap(),
1801 block_map: NodeMap(),
1802 extern_module_map: FxHashMap::default(),
1803 binding_parent_modules: FxHashMap::default(),
1805 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1806 glob_map: NodeMap(),
1808 used_imports: FxHashSet::default(),
1809 maybe_unused_trait_imports: NodeSet(),
1810 maybe_unused_extern_crates: Vec::new(),
1812 unused_labels: FxHashMap::default(),
1814 privacy_errors: Vec::new(),
1815 ambiguity_errors: Vec::new(),
1816 use_injections: Vec::new(),
1817 macro_expanded_macro_export_errors: BTreeSet::new(),
1820 dummy_binding: arenas.alloc_name_binding(NameBinding {
1821 kind: NameBindingKind::Def(Def::Err, false),
1822 expansion: Mark::root(),
1824 vis: ty::Visibility::Public,
1828 macro_names: FxHashSet::default(),
1829 builtin_macros: FxHashMap::default(),
1830 macro_use_prelude: FxHashMap::default(),
1831 all_macros: FxHashMap::default(),
1832 macro_map: FxHashMap::default(),
1835 local_macro_def_scopes: FxHashMap::default(),
1836 name_already_seen: FxHashMap::default(),
1837 whitelisted_legacy_custom_derives: Vec::new(),
1838 potentially_unused_imports: Vec::new(),
1839 struct_constructors: DefIdMap(),
1840 found_unresolved_macro: false,
1841 unused_macros: FxHashSet::default(),
1842 current_type_ascription: Vec::new(),
1843 injected_crate: None,
1847 pub fn arenas() -> ResolverArenas<'a> {
1851 /// Runs the function on each namespace.
1852 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1858 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1860 match self.macro_defs.get(&ctxt.outer()) {
1861 Some(&def_id) => return def_id,
1862 None => ctxt.remove_mark(),
1867 /// Entry point to crate resolution.
1868 pub fn resolve_crate(&mut self, krate: &Crate) {
1869 ImportResolver { resolver: self }.finalize_imports();
1870 self.current_module = self.graph_root;
1871 self.finalize_current_module_macro_resolutions();
1873 visit::walk_crate(self, krate);
1875 check_unused::check_crate(self, krate);
1876 self.report_errors(krate);
1877 self.crate_loader.postprocess(krate);
1884 normal_ancestor_id: DefId,
1888 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1889 self.arenas.alloc_module(module)
1892 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1893 -> bool /* true if an error was reported */ {
1894 match binding.kind {
1895 NameBindingKind::Import { directive, binding, ref used }
1898 directive.used.set(true);
1899 self.used_imports.insert((directive.id, ns));
1900 self.add_to_glob_map(directive.id, ident);
1901 self.record_use(ident, ns, binding)
1903 NameBindingKind::Import { .. } => false,
1904 NameBindingKind::Ambiguity { b1, b2 } => {
1905 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1912 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1913 if self.make_glob_map {
1914 self.glob_map.entry(id).or_default().insert(ident.name);
1918 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1919 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1920 /// `ident` in the first scope that defines it (or None if no scopes define it).
1922 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1923 /// the items are defined in the block. For example,
1926 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1929 /// g(); // This resolves to the local variable `g` since it shadows the item.
1933 /// Invariant: This must only be called during main resolution, not during
1934 /// import resolution.
1935 fn resolve_ident_in_lexical_scope(&mut self,
1938 record_used_id: Option<NodeId>,
1940 -> Option<LexicalScopeBinding<'a>> {
1941 let record_used = record_used_id.is_some();
1942 assert!(ns == TypeNS || ns == ValueNS);
1944 ident.span = if ident.name == keywords::SelfType.name() {
1945 // FIXME(jseyfried) improve `Self` hygiene
1946 ident.span.with_ctxt(SyntaxContext::empty())
1951 ident = ident.modern_and_legacy();
1954 // Walk backwards up the ribs in scope.
1955 let mut module = self.graph_root;
1956 for i in (0 .. self.ribs[ns].len()).rev() {
1957 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1958 // The ident resolves to a type parameter or local variable.
1959 return Some(LexicalScopeBinding::Def(
1960 self.adjust_local_def(ns, i, def, record_used, path_span)
1964 module = match self.ribs[ns][i].kind {
1965 ModuleRibKind(module) => module,
1966 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1967 // If an invocation of this macro created `ident`, give up on `ident`
1968 // and switch to `ident`'s source from the macro definition.
1969 ident.span.remove_mark();
1975 let item = self.resolve_ident_in_module_unadjusted(
1976 ModuleOrUniformRoot::Module(module),
1983 if let Ok(binding) = item {
1984 // The ident resolves to an item.
1985 return Some(LexicalScopeBinding::Item(binding));
1989 ModuleKind::Block(..) => {}, // We can see through blocks
1994 ident.span = ident.span.modern();
1995 let mut poisoned = None;
1997 let opt_module = if let Some(node_id) = record_used_id {
1998 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1999 node_id, &mut poisoned)
2001 self.hygienic_lexical_parent(module, &mut ident.span)
2003 module = unwrap_or!(opt_module, break);
2004 let orig_current_module = self.current_module;
2005 self.current_module = module; // Lexical resolutions can never be a privacy error.
2006 let result = self.resolve_ident_in_module_unadjusted(
2007 ModuleOrUniformRoot::Module(module),
2014 self.current_module = orig_current_module;
2018 if let Some(node_id) = poisoned {
2019 self.session.buffer_lint_with_diagnostic(
2020 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2021 node_id, ident.span,
2022 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2023 lint::builtin::BuiltinLintDiagnostics::
2024 ProcMacroDeriveResolutionFallback(ident.span),
2027 return Some(LexicalScopeBinding::Item(binding))
2029 Err(Determined) => continue,
2030 Err(Undetermined) =>
2031 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2035 if !module.no_implicit_prelude {
2037 if let Some(binding) = self.extern_prelude_get(ident, !record_used, false) {
2038 return Some(LexicalScopeBinding::Item(binding));
2041 if ns == TypeNS && is_known_tool(ident.name) {
2042 let binding = (Def::ToolMod, ty::Visibility::Public,
2043 ident.span, Mark::root()).to_name_binding(self.arenas);
2044 return Some(LexicalScopeBinding::Item(binding));
2046 if let Some(prelude) = self.prelude {
2047 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2048 ModuleOrUniformRoot::Module(prelude),
2055 return Some(LexicalScopeBinding::Item(binding));
2063 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2064 -> Option<Module<'a>> {
2065 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2066 return Some(self.macro_def_scope(span.remove_mark()));
2069 if let ModuleKind::Block(..) = module.kind {
2070 return Some(module.parent.unwrap());
2076 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2077 span: &mut Span, node_id: NodeId,
2078 poisoned: &mut Option<NodeId>)
2079 -> Option<Module<'a>> {
2080 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2084 // We need to support the next case under a deprecation warning
2087 // ---- begin: this comes from a proc macro derive
2088 // mod implementation_details {
2089 // // Note that `MyStruct` is not in scope here.
2090 // impl SomeTrait for MyStruct { ... }
2094 // So we have to fall back to the module's parent during lexical resolution in this case.
2095 if let Some(parent) = module.parent {
2096 // Inner module is inside the macro, parent module is outside of the macro.
2097 if module.expansion != parent.expansion &&
2098 module.expansion.is_descendant_of(parent.expansion) {
2099 // The macro is a proc macro derive
2100 if module.expansion.looks_like_proc_macro_derive() {
2101 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2102 *poisoned = Some(node_id);
2103 return module.parent;
2112 fn resolve_ident_in_module(&mut self,
2113 module: ModuleOrUniformRoot<'a>,
2118 -> Result<&'a NameBinding<'a>, Determinacy> {
2119 ident.span = ident.span.modern();
2120 let orig_current_module = self.current_module;
2121 if let ModuleOrUniformRoot::Module(module) = module {
2122 if let Some(def) = ident.span.adjust(module.expansion) {
2123 self.current_module = self.macro_def_scope(def);
2126 let result = self.resolve_ident_in_module_unadjusted(
2127 module, ident, ns, false, record_used, span,
2129 self.current_module = orig_current_module;
2133 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2134 let mut ctxt = ident.span.ctxt();
2135 let mark = if ident.name == keywords::DollarCrate.name() {
2136 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2137 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2138 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2139 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2140 // definitions actually produced by `macro` and `macro` definitions produced by
2141 // `macro_rules!`, but at least such configurations are not stable yet.
2142 ctxt = ctxt.modern_and_legacy();
2143 let mut iter = ctxt.marks().into_iter().rev().peekable();
2144 let mut result = None;
2145 // Find the last modern mark from the end if it exists.
2146 while let Some(&(mark, transparency)) = iter.peek() {
2147 if transparency == Transparency::Opaque {
2148 result = Some(mark);
2154 // Then find the last legacy mark from the end if it exists.
2155 for (mark, transparency) in iter {
2156 if transparency == Transparency::SemiTransparent {
2157 result = Some(mark);
2164 ctxt = ctxt.modern();
2165 ctxt.adjust(Mark::root())
2167 let module = match mark {
2168 Some(def) => self.macro_def_scope(def),
2169 None => return self.graph_root,
2171 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2174 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2175 let mut module = self.get_module(module.normal_ancestor_id);
2176 while module.span.ctxt().modern() != *ctxt {
2177 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2178 module = self.get_module(parent.normal_ancestor_id);
2185 // We maintain a list of value ribs and type ribs.
2187 // Simultaneously, we keep track of the current position in the module
2188 // graph in the `current_module` pointer. When we go to resolve a name in
2189 // the value or type namespaces, we first look through all the ribs and
2190 // then query the module graph. When we resolve a name in the module
2191 // namespace, we can skip all the ribs (since nested modules are not
2192 // allowed within blocks in Rust) and jump straight to the current module
2195 // Named implementations are handled separately. When we find a method
2196 // call, we consult the module node to find all of the implementations in
2197 // scope. This information is lazily cached in the module node. We then
2198 // generate a fake "implementation scope" containing all the
2199 // implementations thus found, for compatibility with old resolve pass.
2201 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2202 where F: FnOnce(&mut Resolver) -> T
2204 let id = self.definitions.local_def_id(id);
2205 let module = self.module_map.get(&id).cloned(); // clones a reference
2206 if let Some(module) = module {
2207 // Move down in the graph.
2208 let orig_module = replace(&mut self.current_module, module);
2209 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2210 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2212 self.finalize_current_module_macro_resolutions();
2215 self.current_module = orig_module;
2216 self.ribs[ValueNS].pop();
2217 self.ribs[TypeNS].pop();
2224 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2225 /// is returned by the given predicate function
2227 /// Stops after meeting a closure.
2228 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2229 where P: Fn(&Rib, Ident) -> Option<R>
2231 for rib in self.label_ribs.iter().rev() {
2234 // If an invocation of this macro created `ident`, give up on `ident`
2235 // and switch to `ident`'s source from the macro definition.
2236 MacroDefinition(def) => {
2237 if def == self.macro_def(ident.span.ctxt()) {
2238 ident.span.remove_mark();
2242 // Do not resolve labels across function boundary
2246 let r = pred(rib, ident);
2254 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2255 self.with_current_self_item(item, |this| {
2256 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2257 let item_def_id = this.definitions.local_def_id(item.id);
2258 if this.session.features_untracked().self_in_typedefs {
2259 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2260 visit::walk_item(this, item);
2263 visit::walk_item(this, item);
2269 fn resolve_item(&mut self, item: &Item) {
2270 let name = item.ident.name;
2271 debug!("(resolving item) resolving {}", name);
2274 ItemKind::Ty(_, ref generics) |
2275 ItemKind::Fn(_, _, ref generics, _) |
2276 ItemKind::Existential(_, ref generics) => {
2277 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2278 |this| visit::walk_item(this, item));
2281 ItemKind::Enum(_, ref generics) |
2282 ItemKind::Struct(_, ref generics) |
2283 ItemKind::Union(_, ref generics) => {
2284 self.resolve_adt(item, generics);
2287 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2288 self.resolve_implementation(generics,
2294 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2295 // Create a new rib for the trait-wide type parameters.
2296 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2297 let local_def_id = this.definitions.local_def_id(item.id);
2298 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2299 this.visit_generics(generics);
2300 walk_list!(this, visit_param_bound, bounds);
2302 for trait_item in trait_items {
2303 let type_parameters = HasTypeParameters(&trait_item.generics,
2304 TraitOrImplItemRibKind);
2305 this.with_type_parameter_rib(type_parameters, |this| {
2306 match trait_item.node {
2307 TraitItemKind::Const(ref ty, ref default) => {
2310 // Only impose the restrictions of
2311 // ConstRibKind for an actual constant
2312 // expression in a provided default.
2313 if let Some(ref expr) = *default{
2314 this.with_constant_rib(|this| {
2315 this.visit_expr(expr);
2319 TraitItemKind::Method(_, _) => {
2320 visit::walk_trait_item(this, trait_item)
2322 TraitItemKind::Type(..) => {
2323 visit::walk_trait_item(this, trait_item)
2325 TraitItemKind::Macro(_) => {
2326 panic!("unexpanded macro in resolve!")
2335 ItemKind::TraitAlias(ref generics, ref bounds) => {
2336 // Create a new rib for the trait-wide type parameters.
2337 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2338 let local_def_id = this.definitions.local_def_id(item.id);
2339 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2340 this.visit_generics(generics);
2341 walk_list!(this, visit_param_bound, bounds);
2346 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2347 self.with_scope(item.id, |this| {
2348 visit::walk_item(this, item);
2352 ItemKind::Static(ref ty, _, ref expr) |
2353 ItemKind::Const(ref ty, ref expr) => {
2354 self.with_item_rib(|this| {
2356 this.with_constant_rib(|this| {
2357 this.visit_expr(expr);
2362 ItemKind::Use(ref use_tree) => {
2363 // Imports are resolved as global by default, add starting root segment.
2365 segments: use_tree.prefix.make_root().into_iter().collect(),
2366 span: use_tree.span,
2368 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2371 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2372 // do nothing, these are just around to be encoded
2375 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2379 /// For the most part, use trees are desugared into `ImportDirective` instances
2380 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2381 /// there is one special case we handle here: an empty nested import like
2382 /// `a::{b::{}}`, which desugares into...no import directives.
2383 fn resolve_use_tree(
2388 use_tree: &ast::UseTree,
2391 match use_tree.kind {
2392 ast::UseTreeKind::Nested(ref items) => {
2394 segments: prefix.segments
2396 .chain(use_tree.prefix.segments.iter())
2399 span: prefix.span.to(use_tree.prefix.span),
2402 if items.is_empty() {
2403 // Resolve prefix of an import with empty braces (issue #28388).
2404 self.smart_resolve_path_with_crate_lint(
2408 PathSource::ImportPrefix,
2409 CrateLint::UsePath { root_id, root_span },
2412 for &(ref tree, nested_id) in items {
2413 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2417 ast::UseTreeKind::Simple(..) => {},
2418 ast::UseTreeKind::Glob => {},
2422 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2423 where F: FnOnce(&mut Resolver)
2425 match type_parameters {
2426 HasTypeParameters(generics, rib_kind) => {
2427 let mut function_type_rib = Rib::new(rib_kind);
2428 let mut seen_bindings = FxHashMap::default();
2429 for param in &generics.params {
2431 GenericParamKind::Lifetime { .. } => {}
2432 GenericParamKind::Type { .. } => {
2433 let ident = param.ident.modern();
2434 debug!("with_type_parameter_rib: {}", param.id);
2436 if seen_bindings.contains_key(&ident) {
2437 let span = seen_bindings.get(&ident).unwrap();
2438 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2442 resolve_error(self, param.ident.span, err);
2444 seen_bindings.entry(ident).or_insert(param.ident.span);
2446 // Plain insert (no renaming).
2447 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2448 function_type_rib.bindings.insert(ident, def);
2449 self.record_def(param.id, PathResolution::new(def));
2453 self.ribs[TypeNS].push(function_type_rib);
2456 NoTypeParameters => {
2463 if let HasTypeParameters(..) = type_parameters {
2464 self.ribs[TypeNS].pop();
2468 fn with_label_rib<F>(&mut self, f: F)
2469 where F: FnOnce(&mut Resolver)
2471 self.label_ribs.push(Rib::new(NormalRibKind));
2473 self.label_ribs.pop();
2476 fn with_item_rib<F>(&mut self, f: F)
2477 where F: FnOnce(&mut Resolver)
2479 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2480 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2482 self.ribs[TypeNS].pop();
2483 self.ribs[ValueNS].pop();
2486 fn with_constant_rib<F>(&mut self, f: F)
2487 where F: FnOnce(&mut Resolver)
2489 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2490 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2492 self.label_ribs.pop();
2493 self.ribs[ValueNS].pop();
2496 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2497 where F: FnOnce(&mut Resolver) -> T
2499 // Handle nested impls (inside fn bodies)
2500 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2501 let result = f(self);
2502 self.current_self_type = previous_value;
2506 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2507 where F: FnOnce(&mut Resolver) -> T
2509 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2510 let result = f(self);
2511 self.current_self_item = previous_value;
2515 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2516 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2517 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2519 let mut new_val = None;
2520 let mut new_id = None;
2521 if let Some(trait_ref) = opt_trait_ref {
2522 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2523 let def = self.smart_resolve_path_fragment(
2527 trait_ref.path.span,
2528 PathSource::Trait(AliasPossibility::No),
2529 CrateLint::SimplePath(trait_ref.ref_id),
2531 if def != Def::Err {
2532 new_id = Some(def.def_id());
2533 let span = trait_ref.path.span;
2534 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2541 CrateLint::SimplePath(trait_ref.ref_id),
2544 new_val = Some((module, trait_ref.clone()));
2548 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2549 let result = f(self, new_id);
2550 self.current_trait_ref = original_trait_ref;
2554 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2555 where F: FnOnce(&mut Resolver)
2557 let mut self_type_rib = Rib::new(NormalRibKind);
2559 // plain insert (no renaming, types are not currently hygienic....)
2560 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2561 self.ribs[TypeNS].push(self_type_rib);
2563 self.ribs[TypeNS].pop();
2566 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2567 where F: FnOnce(&mut Resolver)
2569 let self_def = Def::SelfCtor(impl_id);
2570 let mut self_type_rib = Rib::new(NormalRibKind);
2571 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2572 self.ribs[ValueNS].push(self_type_rib);
2574 self.ribs[ValueNS].pop();
2577 fn resolve_implementation(&mut self,
2578 generics: &Generics,
2579 opt_trait_reference: &Option<TraitRef>,
2582 impl_items: &[ImplItem]) {
2583 // If applicable, create a rib for the type parameters.
2584 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2585 // Dummy self type for better errors if `Self` is used in the trait path.
2586 this.with_self_rib(Def::SelfTy(None, None), |this| {
2587 // Resolve the trait reference, if necessary.
2588 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2589 let item_def_id = this.definitions.local_def_id(item_id);
2590 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2591 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2592 // Resolve type arguments in the trait path.
2593 visit::walk_trait_ref(this, trait_ref);
2595 // Resolve the self type.
2596 this.visit_ty(self_type);
2597 // Resolve the type parameters.
2598 this.visit_generics(generics);
2599 // Resolve the items within the impl.
2600 this.with_current_self_type(self_type, |this| {
2601 this.with_self_struct_ctor_rib(item_def_id, |this| {
2602 for impl_item in impl_items {
2603 this.resolve_visibility(&impl_item.vis);
2605 // We also need a new scope for the impl item type parameters.
2606 let type_parameters = HasTypeParameters(&impl_item.generics,
2607 TraitOrImplItemRibKind);
2608 this.with_type_parameter_rib(type_parameters, |this| {
2609 use self::ResolutionError::*;
2610 match impl_item.node {
2611 ImplItemKind::Const(..) => {
2612 // If this is a trait impl, ensure the const
2614 this.check_trait_item(impl_item.ident,
2617 |n, s| ConstNotMemberOfTrait(n, s));
2618 this.with_constant_rib(|this|
2619 visit::walk_impl_item(this, impl_item)
2622 ImplItemKind::Method(..) => {
2623 // If this is a trait impl, ensure the method
2625 this.check_trait_item(impl_item.ident,
2628 |n, s| MethodNotMemberOfTrait(n, s));
2630 visit::walk_impl_item(this, impl_item);
2632 ImplItemKind::Type(ref ty) => {
2633 // If this is a trait impl, ensure the type
2635 this.check_trait_item(impl_item.ident,
2638 |n, s| TypeNotMemberOfTrait(n, s));
2642 ImplItemKind::Existential(ref bounds) => {
2643 // If this is a trait impl, ensure the type
2645 this.check_trait_item(impl_item.ident,
2648 |n, s| TypeNotMemberOfTrait(n, s));
2650 for bound in bounds {
2651 this.visit_param_bound(bound);
2654 ImplItemKind::Macro(_) =>
2655 panic!("unexpanded macro in resolve!"),
2667 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2668 where F: FnOnce(Name, &str) -> ResolutionError
2670 // If there is a TraitRef in scope for an impl, then the method must be in the
2672 if let Some((module, _)) = self.current_trait_ref {
2673 if self.resolve_ident_in_module(
2674 ModuleOrUniformRoot::Module(module),
2680 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2681 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2686 fn resolve_local(&mut self, local: &Local) {
2687 // Resolve the type.
2688 walk_list!(self, visit_ty, &local.ty);
2690 // Resolve the initializer.
2691 walk_list!(self, visit_expr, &local.init);
2693 // Resolve the pattern.
2694 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2697 // build a map from pattern identifiers to binding-info's.
2698 // this is done hygienically. This could arise for a macro
2699 // that expands into an or-pattern where one 'x' was from the
2700 // user and one 'x' came from the macro.
2701 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2702 let mut binding_map = FxHashMap::default();
2704 pat.walk(&mut |pat| {
2705 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2706 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2707 Some(Def::Local(..)) => true,
2710 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2711 binding_map.insert(ident, binding_info);
2720 // check that all of the arms in an or-pattern have exactly the
2721 // same set of bindings, with the same binding modes for each.
2722 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2723 if pats.is_empty() {
2727 let mut missing_vars = FxHashMap::default();
2728 let mut inconsistent_vars = FxHashMap::default();
2729 for (i, p) in pats.iter().enumerate() {
2730 let map_i = self.binding_mode_map(&p);
2732 for (j, q) in pats.iter().enumerate() {
2737 let map_j = self.binding_mode_map(&q);
2738 for (&key, &binding_i) in &map_i {
2739 if map_j.is_empty() { // Account for missing bindings when
2740 let binding_error = missing_vars // map_j has none.
2742 .or_insert(BindingError {
2744 origin: BTreeSet::new(),
2745 target: BTreeSet::new(),
2747 binding_error.origin.insert(binding_i.span);
2748 binding_error.target.insert(q.span);
2750 for (&key_j, &binding_j) in &map_j {
2751 match map_i.get(&key_j) {
2752 None => { // missing binding
2753 let binding_error = missing_vars
2755 .or_insert(BindingError {
2757 origin: BTreeSet::new(),
2758 target: BTreeSet::new(),
2760 binding_error.origin.insert(binding_j.span);
2761 binding_error.target.insert(p.span);
2763 Some(binding_i) => { // check consistent binding
2764 if binding_i.binding_mode != binding_j.binding_mode {
2767 .or_insert((binding_j.span, binding_i.span));
2775 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2776 missing_vars.sort();
2777 for (_, v) in missing_vars {
2779 *v.origin.iter().next().unwrap(),
2780 ResolutionError::VariableNotBoundInPattern(v));
2782 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2783 inconsistent_vars.sort();
2784 for (name, v) in inconsistent_vars {
2785 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2789 fn resolve_arm(&mut self, arm: &Arm) {
2790 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2792 let mut bindings_list = FxHashMap::default();
2793 for pattern in &arm.pats {
2794 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2797 // This has to happen *after* we determine which pat_idents are variants
2798 self.check_consistent_bindings(&arm.pats);
2800 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2801 self.visit_expr(expr)
2803 self.visit_expr(&arm.body);
2805 self.ribs[ValueNS].pop();
2808 fn resolve_block(&mut self, block: &Block) {
2809 debug!("(resolving block) entering block");
2810 // Move down in the graph, if there's an anonymous module rooted here.
2811 let orig_module = self.current_module;
2812 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2814 let mut num_macro_definition_ribs = 0;
2815 if let Some(anonymous_module) = anonymous_module {
2816 debug!("(resolving block) found anonymous module, moving down");
2817 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2818 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2819 self.current_module = anonymous_module;
2820 self.finalize_current_module_macro_resolutions();
2822 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2825 // Descend into the block.
2826 for stmt in &block.stmts {
2827 if let ast::StmtKind::Item(ref item) = stmt.node {
2828 if let ast::ItemKind::MacroDef(..) = item.node {
2829 num_macro_definition_ribs += 1;
2830 let def = self.definitions.local_def_id(item.id);
2831 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2832 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2836 self.visit_stmt(stmt);
2840 self.current_module = orig_module;
2841 for _ in 0 .. num_macro_definition_ribs {
2842 self.ribs[ValueNS].pop();
2843 self.label_ribs.pop();
2845 self.ribs[ValueNS].pop();
2846 if anonymous_module.is_some() {
2847 self.ribs[TypeNS].pop();
2849 debug!("(resolving block) leaving block");
2852 fn fresh_binding(&mut self,
2855 outer_pat_id: NodeId,
2856 pat_src: PatternSource,
2857 bindings: &mut FxHashMap<Ident, NodeId>)
2859 // Add the binding to the local ribs, if it
2860 // doesn't already exist in the bindings map. (We
2861 // must not add it if it's in the bindings map
2862 // because that breaks the assumptions later
2863 // passes make about or-patterns.)
2864 let ident = ident.modern_and_legacy();
2865 let mut def = Def::Local(pat_id);
2866 match bindings.get(&ident).cloned() {
2867 Some(id) if id == outer_pat_id => {
2868 // `Variant(a, a)`, error
2872 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2876 Some(..) if pat_src == PatternSource::FnParam => {
2877 // `fn f(a: u8, a: u8)`, error
2881 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2885 Some(..) if pat_src == PatternSource::Match ||
2886 pat_src == PatternSource::IfLet ||
2887 pat_src == PatternSource::WhileLet => {
2888 // `Variant1(a) | Variant2(a)`, ok
2889 // Reuse definition from the first `a`.
2890 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2893 span_bug!(ident.span, "two bindings with the same name from \
2894 unexpected pattern source {:?}", pat_src);
2897 // A completely fresh binding, add to the lists if it's valid.
2898 if ident.name != keywords::Invalid.name() {
2899 bindings.insert(ident, outer_pat_id);
2900 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2905 PathResolution::new(def)
2908 fn resolve_pattern(&mut self,
2910 pat_src: PatternSource,
2911 // Maps idents to the node ID for the
2912 // outermost pattern that binds them.
2913 bindings: &mut FxHashMap<Ident, NodeId>) {
2914 // Visit all direct subpatterns of this pattern.
2915 let outer_pat_id = pat.id;
2916 pat.walk(&mut |pat| {
2918 PatKind::Ident(bmode, ident, ref opt_pat) => {
2919 // First try to resolve the identifier as some existing
2920 // entity, then fall back to a fresh binding.
2921 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2923 .and_then(LexicalScopeBinding::item);
2924 let resolution = binding.map(NameBinding::def).and_then(|def| {
2925 let is_syntactic_ambiguity = opt_pat.is_none() &&
2926 bmode == BindingMode::ByValue(Mutability::Immutable);
2928 Def::StructCtor(_, CtorKind::Const) |
2929 Def::VariantCtor(_, CtorKind::Const) |
2930 Def::Const(..) if is_syntactic_ambiguity => {
2931 // Disambiguate in favor of a unit struct/variant
2932 // or constant pattern.
2933 self.record_use(ident, ValueNS, binding.unwrap());
2934 Some(PathResolution::new(def))
2936 Def::StructCtor(..) | Def::VariantCtor(..) |
2937 Def::Const(..) | Def::Static(..) => {
2938 // This is unambiguously a fresh binding, either syntactically
2939 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2940 // to something unusable as a pattern (e.g. constructor function),
2941 // but we still conservatively report an error, see
2942 // issues/33118#issuecomment-233962221 for one reason why.
2946 ResolutionError::BindingShadowsSomethingUnacceptable(
2947 pat_src.descr(), ident.name, binding.unwrap())
2951 Def::Fn(..) | Def::Err => {
2952 // These entities are explicitly allowed
2953 // to be shadowed by fresh bindings.
2957 span_bug!(ident.span, "unexpected definition for an \
2958 identifier in pattern: {:?}", def);
2961 }).unwrap_or_else(|| {
2962 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2965 self.record_def(pat.id, resolution);
2968 PatKind::TupleStruct(ref path, ..) => {
2969 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2972 PatKind::Path(ref qself, ref path) => {
2973 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2976 PatKind::Struct(ref path, ..) => {
2977 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2985 visit::walk_pat(self, pat);
2988 // High-level and context dependent path resolution routine.
2989 // Resolves the path and records the resolution into definition map.
2990 // If resolution fails tries several techniques to find likely
2991 // resolution candidates, suggest imports or other help, and report
2992 // errors in user friendly way.
2993 fn smart_resolve_path(&mut self,
2995 qself: Option<&QSelf>,
2999 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3002 /// A variant of `smart_resolve_path` where you also specify extra
3003 /// information about where the path came from; this extra info is
3004 /// sometimes needed for the lint that recommends rewriting
3005 /// absolute paths to `crate`, so that it knows how to frame the
3006 /// suggestion. If you are just resolving a path like `foo::bar`
3007 /// that appears...somewhere, though, then you just want
3008 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3009 /// already provides.
3010 fn smart_resolve_path_with_crate_lint(
3013 qself: Option<&QSelf>,
3016 crate_lint: CrateLint
3017 ) -> PathResolution {
3018 self.smart_resolve_path_fragment(
3021 &Segment::from_path(path),
3028 fn smart_resolve_path_fragment(&mut self,
3030 qself: Option<&QSelf>,
3034 crate_lint: CrateLint)
3036 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3037 let ns = source.namespace();
3038 let is_expected = &|def| source.is_expected(def);
3039 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3041 // Base error is amended with one short label and possibly some longer helps/notes.
3042 let report_errors = |this: &mut Self, def: Option<Def>| {
3043 // Make the base error.
3044 let expected = source.descr_expected();
3045 let path_str = names_to_string(path);
3046 let item_str = path.last().unwrap().ident;
3047 let code = source.error_code(def.is_some());
3048 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3049 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3050 format!("not a {}", expected),
3053 let item_span = path.last().unwrap().ident.span;
3054 let (mod_prefix, mod_str) = if path.len() == 1 {
3055 (String::new(), "this scope".to_string())
3056 } else if path.len() == 2 && path[0].ident.name == keywords::CrateRoot.name() {
3057 (String::new(), "the crate root".to_string())
3059 let mod_path = &path[..path.len() - 1];
3060 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
3061 false, span, CrateLint::No) {
3062 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3065 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3066 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3068 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3069 format!("not found in {}", mod_str),
3072 let code = DiagnosticId::Error(code.into());
3073 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3075 // Emit help message for fake-self from other languages like `this`(javascript)
3076 if ["this", "my"].contains(&&*item_str.as_str())
3077 && this.self_value_is_available(path[0].ident.span, span) {
3078 err.span_suggestion_with_applicability(
3082 Applicability::MaybeIncorrect,
3086 // Emit special messages for unresolved `Self` and `self`.
3087 if is_self_type(path, ns) {
3088 __diagnostic_used!(E0411);
3089 err.code(DiagnosticId::Error("E0411".into()));
3090 let available_in = if this.session.features_untracked().self_in_typedefs {
3091 "impls, traits, and type definitions"
3095 err.span_label(span, format!("`Self` is only available in {}", available_in));
3096 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3097 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3100 return (err, Vec::new());
3102 if is_self_value(path, ns) {
3103 __diagnostic_used!(E0424);
3104 err.code(DiagnosticId::Error("E0424".into()));
3105 err.span_label(span, format!("`self` value is a keyword \
3107 methods with `self` parameter"));
3108 return (err, Vec::new());
3111 // Try to lookup the name in more relaxed fashion for better error reporting.
3112 let ident = path.last().unwrap().ident;
3113 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3114 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3115 let enum_candidates =
3116 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3117 let mut enum_candidates = enum_candidates.iter()
3118 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3119 enum_candidates.sort();
3120 for (sp, variant_path, enum_path) in enum_candidates {
3122 let msg = format!("there is an enum variant `{}`, \
3128 err.span_suggestion_with_applicability(
3130 "you can try using the variant's enum",
3132 Applicability::MachineApplicable,
3137 if path.len() == 1 && this.self_type_is_available(span) {
3138 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3139 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3141 AssocSuggestion::Field => {
3142 err.span_suggestion_with_applicability(
3145 format!("self.{}", path_str),
3146 Applicability::MachineApplicable,
3148 if !self_is_available {
3149 err.span_label(span, format!("`self` value is a keyword \
3151 methods with `self` parameter"));
3154 AssocSuggestion::MethodWithSelf if self_is_available => {
3155 err.span_suggestion_with_applicability(
3158 format!("self.{}", path_str),
3159 Applicability::MachineApplicable,
3162 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3163 err.span_suggestion_with_applicability(
3166 format!("Self::{}", path_str),
3167 Applicability::MachineApplicable,
3171 return (err, candidates);
3175 let mut levenshtein_worked = false;
3178 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3179 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3180 levenshtein_worked = true;
3183 // Try context dependent help if relaxed lookup didn't work.
3184 if let Some(def) = def {
3185 match (def, source) {
3186 (Def::Macro(..), _) => {
3187 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3188 return (err, candidates);
3190 (Def::TyAlias(..), PathSource::Trait(_)) => {
3191 err.span_label(span, "type aliases cannot be used for traits");
3192 return (err, candidates);
3194 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3195 ExprKind::Field(_, ident) => {
3196 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3198 return (err, candidates);
3200 ExprKind::MethodCall(ref segment, ..) => {
3201 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3202 path_str, segment.ident));
3203 return (err, candidates);
3207 (Def::Enum(..), PathSource::TupleStruct)
3208 | (Def::Enum(..), PathSource::Expr(..)) => {
3209 if let Some(variants) = this.collect_enum_variants(def) {
3210 err.note(&format!("did you mean to use one \
3211 of the following variants?\n{}",
3213 .map(|suggestion| path_names_to_string(suggestion))
3214 .map(|suggestion| format!("- `{}`", suggestion))
3215 .collect::<Vec<_>>()
3219 err.note("did you mean to use one of the enum's variants?");
3221 return (err, candidates);
3223 (Def::Struct(def_id), _) if ns == ValueNS => {
3224 if let Some((ctor_def, ctor_vis))
3225 = this.struct_constructors.get(&def_id).cloned() {
3226 let accessible_ctor = this.is_accessible(ctor_vis);
3227 if is_expected(ctor_def) && !accessible_ctor {
3228 err.span_label(span, format!("constructor is not visible \
3229 here due to private fields"));
3232 // HACK(estebank): find a better way to figure out that this was a
3233 // parser issue where a struct literal is being used on an expression
3234 // where a brace being opened means a block is being started. Look
3235 // ahead for the next text to see if `span` is followed by a `{`.
3236 let sm = this.session.source_map();
3239 sp = sm.next_point(sp);
3240 match sm.span_to_snippet(sp) {
3241 Ok(ref snippet) => {
3242 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3249 let followed_by_brace = match sm.span_to_snippet(sp) {
3250 Ok(ref snippet) if snippet == "{" => true,
3254 PathSource::Expr(Some(parent)) => {
3256 ExprKind::MethodCall(ref path_assignment, _) => {
3257 err.span_suggestion_with_applicability(
3258 sm.start_point(parent.span)
3259 .to(path_assignment.ident.span),
3260 "use `::` to access an associated function",
3263 path_assignment.ident),
3264 Applicability::MaybeIncorrect
3266 return (err, candidates);
3271 format!("did you mean `{} {{ /* fields */ }}`?",
3274 return (err, candidates);
3278 PathSource::Expr(None) if followed_by_brace == true => {
3281 format!("did you mean `({} {{ /* fields */ }})`?",
3284 return (err, candidates);
3289 format!("did you mean `{} {{ /* fields */ }}`?",
3292 return (err, candidates);
3296 return (err, candidates);
3298 (Def::Union(..), _) |
3299 (Def::Variant(..), _) |
3300 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3301 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3303 return (err, candidates);
3305 (Def::SelfTy(..), _) if ns == ValueNS => {
3306 err.span_label(span, fallback_label);
3307 err.note("can't use `Self` as a constructor, you must use the \
3308 implemented struct");
3309 return (err, candidates);
3311 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3312 err.note("can't use a type alias as a constructor");
3313 return (err, candidates);
3320 if !levenshtein_worked {
3321 err.span_label(base_span, fallback_label);
3322 this.type_ascription_suggestion(&mut err, base_span);
3326 let report_errors = |this: &mut Self, def: Option<Def>| {
3327 let (err, candidates) = report_errors(this, def);
3328 let def_id = this.current_module.normal_ancestor_id;
3329 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3330 let better = def.is_some();
3331 this.use_injections.push(UseError { err, candidates, node_id, better });
3332 err_path_resolution()
3335 let resolution = match self.resolve_qpath_anywhere(
3341 source.defer_to_typeck(),
3342 source.global_by_default(),
3345 Some(resolution) if resolution.unresolved_segments() == 0 => {
3346 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3349 // Add a temporary hack to smooth the transition to new struct ctor
3350 // visibility rules. See #38932 for more details.
3352 if let Def::Struct(def_id) = resolution.base_def() {
3353 if let Some((ctor_def, ctor_vis))
3354 = self.struct_constructors.get(&def_id).cloned() {
3355 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3356 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3357 self.session.buffer_lint(lint, id, span,
3358 "private struct constructors are not usable through \
3359 re-exports in outer modules",
3361 res = Some(PathResolution::new(ctor_def));
3366 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3369 Some(resolution) if source.defer_to_typeck() => {
3370 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3371 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3372 // it needs to be added to the trait map.
3374 let item_name = path.last().unwrap().ident;
3375 let traits = self.get_traits_containing_item(item_name, ns);
3376 self.trait_map.insert(id, traits);
3380 _ => report_errors(self, None)
3383 if let PathSource::TraitItem(..) = source {} else {
3384 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3385 self.record_def(id, resolution);
3390 fn type_ascription_suggestion(&self,
3391 err: &mut DiagnosticBuilder,
3393 debug!("type_ascription_suggetion {:?}", base_span);
3394 let cm = self.session.source_map();
3395 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3396 if let Some(sp) = self.current_type_ascription.last() {
3398 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3399 sp = cm.next_point(sp);
3400 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3401 debug!("snippet {:?}", snippet);
3402 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3403 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3404 debug!("{:?} {:?}", line_sp, line_base_sp);
3406 err.span_label(base_span,
3407 "expecting a type here because of type ascription");
3408 if line_sp != line_base_sp {
3409 err.span_suggestion_short_with_applicability(
3411 "did you mean to use `;` here instead?",
3413 Applicability::MaybeIncorrect,
3417 } else if !snippet.trim().is_empty() {
3418 debug!("tried to find type ascription `:` token, couldn't find it");
3428 fn self_type_is_available(&mut self, span: Span) -> bool {
3429 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3430 TypeNS, None, span);
3431 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3434 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3435 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3436 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3437 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3440 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3441 fn resolve_qpath_anywhere(&mut self,
3443 qself: Option<&QSelf>,
3445 primary_ns: Namespace,
3447 defer_to_typeck: bool,
3448 global_by_default: bool,
3449 crate_lint: CrateLint)
3450 -> Option<PathResolution> {
3451 let mut fin_res = None;
3452 // FIXME: can't resolve paths in macro namespace yet, macros are
3453 // processed by the little special hack below.
3454 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3455 if i == 0 || ns != primary_ns {
3456 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3457 // If defer_to_typeck, then resolution > no resolution,
3458 // otherwise full resolution > partial resolution > no resolution.
3459 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3461 res => if fin_res.is_none() { fin_res = res },
3465 if primary_ns != MacroNS &&
3466 (self.macro_names.contains(&path[0].ident.modern()) ||
3467 self.builtin_macros.get(&path[0].ident.name).cloned()
3468 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3469 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3470 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3471 // Return some dummy definition, it's enough for error reporting.
3473 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3479 /// Handles paths that may refer to associated items.
3480 fn resolve_qpath(&mut self,
3482 qself: Option<&QSelf>,
3486 global_by_default: bool,
3487 crate_lint: CrateLint)
3488 -> Option<PathResolution> {
3490 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3491 ns={:?}, span={:?}, global_by_default={:?})",
3500 if let Some(qself) = qself {
3501 if qself.position == 0 {
3502 // This is a case like `<T>::B`, where there is no
3503 // trait to resolve. In that case, we leave the `B`
3504 // segment to be resolved by type-check.
3505 return Some(PathResolution::with_unresolved_segments(
3506 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3510 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3512 // Currently, `path` names the full item (`A::B::C`, in
3513 // our example). so we extract the prefix of that that is
3514 // the trait (the slice upto and including
3515 // `qself.position`). And then we recursively resolve that,
3516 // but with `qself` set to `None`.
3518 // However, setting `qself` to none (but not changing the
3519 // span) loses the information about where this path
3520 // *actually* appears, so for the purposes of the crate
3521 // lint we pass along information that this is the trait
3522 // name from a fully qualified path, and this also
3523 // contains the full span (the `CrateLint::QPathTrait`).
3524 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3525 let res = self.smart_resolve_path_fragment(
3528 &path[..qself.position + 1],
3530 PathSource::TraitItem(ns),
3531 CrateLint::QPathTrait {
3533 qpath_span: qself.path_span,
3537 // The remaining segments (the `C` in our example) will
3538 // have to be resolved by type-check, since that requires doing
3539 // trait resolution.
3540 return Some(PathResolution::with_unresolved_segments(
3541 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3545 let result = match self.resolve_path(
3553 PathResult::NonModule(path_res) => path_res,
3554 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3555 PathResolution::new(module.def().unwrap())
3557 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3558 // don't report an error right away, but try to fallback to a primitive type.
3559 // So, we are still able to successfully resolve something like
3561 // use std::u8; // bring module u8 in scope
3562 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3563 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3564 // // not to non-existent std::u8::max_value
3567 // Such behavior is required for backward compatibility.
3568 // The same fallback is used when `a` resolves to nothing.
3569 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3570 PathResult::Failed(..)
3571 if (ns == TypeNS || path.len() > 1) &&
3572 self.primitive_type_table.primitive_types
3573 .contains_key(&path[0].ident.name) => {
3574 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3575 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3577 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3578 PathResolution::new(module.def().unwrap()),
3579 PathResult::Failed(span, msg, false) => {
3580 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3581 err_path_resolution()
3583 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3584 PathResult::Failed(..) => return None,
3585 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3588 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3589 path[0].ident.name != keywords::CrateRoot.name() &&
3590 path[0].ident.name != keywords::DollarCrate.name() {
3591 let unqualified_result = {
3592 match self.resolve_path(
3594 &[*path.last().unwrap()],
3600 PathResult::NonModule(path_res) => path_res.base_def(),
3601 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3602 module.def().unwrap(),
3603 _ => return Some(result),
3606 if result.base_def() == unqualified_result {
3607 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3608 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3617 base_module: Option<ModuleOrUniformRoot<'a>>,
3619 opt_ns: Option<Namespace>, // `None` indicates a module path
3622 crate_lint: CrateLint,
3623 ) -> PathResult<'a> {
3624 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3625 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3626 record_used, path_span, crate_lint)
3629 fn resolve_path_with_parent_scope(
3631 base_module: Option<ModuleOrUniformRoot<'a>>,
3633 opt_ns: Option<Namespace>, // `None` indicates a module path
3634 parent_scope: &ParentScope<'a>,
3637 crate_lint: CrateLint,
3638 ) -> PathResult<'a> {
3639 let mut module = base_module;
3640 let mut allow_super = true;
3641 let mut second_binding = None;
3642 self.current_module = parent_scope.module;
3645 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3646 path_span={:?}, crate_lint={:?})",
3654 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3655 debug!("resolve_path ident {} {:?}", i, ident);
3657 let is_last = i == path.len() - 1;
3658 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3659 let name = ident.name;
3661 allow_super &= ns == TypeNS &&
3662 (name == keywords::SelfValue.name() ||
3663 name == keywords::Super.name());
3666 if allow_super && name == keywords::Super.name() {
3667 let mut ctxt = ident.span.ctxt().modern();
3668 let self_module = match i {
3669 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3671 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3675 if let Some(self_module) = self_module {
3676 if let Some(parent) = self_module.parent {
3677 module = Some(ModuleOrUniformRoot::Module(
3678 self.resolve_self(&mut ctxt, parent)));
3682 let msg = "There are too many initial `super`s.".to_string();
3683 return PathResult::Failed(ident.span, msg, false);
3686 if name == keywords::SelfValue.name() {
3687 let mut ctxt = ident.span.ctxt().modern();
3688 module = Some(ModuleOrUniformRoot::Module(
3689 self.resolve_self(&mut ctxt, self.current_module)));
3692 if name == keywords::Extern.name() ||
3693 name == keywords::CrateRoot.name() &&
3694 self.session.rust_2018() {
3695 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3698 if name == keywords::CrateRoot.name() ||
3699 name == keywords::Crate.name() ||
3700 name == keywords::DollarCrate.name() {
3701 // `::a::b`, `crate::a::b` or `$crate::a::b`
3702 module = Some(ModuleOrUniformRoot::Module(
3703 self.resolve_crate_root(ident)));
3709 // Report special messages for path segment keywords in wrong positions.
3710 if ident.is_path_segment_keyword() && i != 0 {
3711 let name_str = if name == keywords::CrateRoot.name() {
3712 "crate root".to_string()
3714 format!("`{}`", name)
3716 let msg = if i == 1 && path[0].ident.name == keywords::CrateRoot.name() {
3717 format!("global paths cannot start with {}", name_str)
3719 format!("{} in paths can only be used in start position", name_str)
3721 return PathResult::Failed(ident.span, msg, false);
3724 let binding = if let Some(module) = module {
3725 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3726 } else if opt_ns == Some(MacroNS) {
3727 assert!(ns == TypeNS);
3728 self.early_resolve_ident_in_lexical_scope(ident, ns, None, parent_scope,
3729 record_used, record_used, path_span)
3731 let record_used_id =
3732 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3733 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3734 // we found a locally-imported or available item/module
3735 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3736 // we found a local variable or type param
3737 Some(LexicalScopeBinding::Def(def))
3738 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3739 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3743 _ => Err(if record_used { Determined } else { Undetermined }),
3750 second_binding = Some(binding);
3752 let def = binding.def();
3753 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3754 if let Some(next_module) = binding.module() {
3755 module = Some(ModuleOrUniformRoot::Module(next_module));
3757 if let Some(id) = id {
3758 if !self.def_map.contains_key(&id) {
3759 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3760 self.record_def(id, PathResolution::new(def));
3764 } else if def == Def::ToolMod && i + 1 != path.len() {
3765 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3766 return PathResult::NonModule(PathResolution::new(def));
3767 } else if def == Def::Err {
3768 return PathResult::NonModule(err_path_resolution());
3769 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3770 self.lint_if_path_starts_with_module(
3776 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3777 def, path.len() - i - 1
3780 return PathResult::Failed(ident.span,
3781 format!("Not a module `{}`", ident),
3785 Err(Undetermined) => return PathResult::Indeterminate,
3786 Err(Determined) => {
3787 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3788 if opt_ns.is_some() && !module.is_normal() {
3789 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3790 module.def().unwrap(), path.len() - i
3794 let module_def = match module {
3795 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3798 let msg = if module_def == self.graph_root.def() {
3799 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3800 let mut candidates =
3801 self.lookup_import_candidates(name, TypeNS, is_mod);
3802 candidates.sort_by_cached_key(|c| {
3803 (c.path.segments.len(), c.path.to_string())
3805 if let Some(candidate) = candidates.get(0) {
3806 format!("Did you mean `{}`?", candidate.path)
3808 format!("Maybe a missing `extern crate {};`?", ident)
3811 format!("Use of undeclared type or module `{}`", ident)
3813 format!("Could not find `{}` in `{}`", ident, path[i - 1].ident)
3815 return PathResult::Failed(ident.span, msg, is_last);
3820 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3822 PathResult::Module(module.unwrap_or_else(|| {
3823 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3828 fn lint_if_path_starts_with_module(
3830 crate_lint: CrateLint,
3833 second_binding: Option<&NameBinding>,
3835 // In the 2018 edition this lint is a hard error, so nothing to do
3836 if self.session.rust_2018() {
3840 let (diag_id, diag_span) = match crate_lint {
3841 CrateLint::No => return,
3842 CrateLint::SimplePath(id) => (id, path_span),
3843 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3844 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3847 let first_name = match path.get(0) {
3848 Some(ident) => ident.ident.name,
3852 // We're only interested in `use` paths which should start with
3853 // `{{root}}` or `extern` currently.
3854 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3859 // If this import looks like `crate::...` it's already good
3860 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3861 // Otherwise go below to see if it's an extern crate
3863 // If the path has length one (and it's `CrateRoot` most likely)
3864 // then we don't know whether we're gonna be importing a crate or an
3865 // item in our crate. Defer this lint to elsewhere
3869 // If the first element of our path was actually resolved to an
3870 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3871 // warning, this looks all good!
3872 if let Some(binding) = second_binding {
3873 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3874 // Careful: we still want to rewrite paths from
3875 // renamed extern crates.
3876 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3882 let diag = lint::builtin::BuiltinLintDiagnostics
3883 ::AbsPathWithModule(diag_span);
3884 self.session.buffer_lint_with_diagnostic(
3885 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3887 "absolute paths must start with `self`, `super`, \
3888 `crate`, or an external crate name in the 2018 edition",
3892 // Resolve a local definition, potentially adjusting for closures.
3893 fn adjust_local_def(&mut self,
3898 span: Span) -> Def {
3899 let ribs = &self.ribs[ns][rib_index + 1..];
3901 // An invalid forward use of a type parameter from a previous default.
3902 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3904 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3906 assert_eq!(def, Def::Err);
3912 span_bug!(span, "unexpected {:?} in bindings", def)
3914 Def::Local(node_id) => {
3917 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3918 ForwardTyParamBanRibKind => {
3919 // Nothing to do. Continue.
3921 ClosureRibKind(function_id) => {
3924 let seen = self.freevars_seen
3927 if let Some(&index) = seen.get(&node_id) {
3928 def = Def::Upvar(node_id, index, function_id);
3931 let vec = self.freevars
3934 let depth = vec.len();
3935 def = Def::Upvar(node_id, depth, function_id);
3942 seen.insert(node_id, depth);
3945 ItemRibKind | TraitOrImplItemRibKind => {
3946 // This was an attempt to access an upvar inside a
3947 // named function item. This is not allowed, so we
3950 resolve_error(self, span,
3951 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3955 ConstantItemRibKind => {
3956 // Still doesn't deal with upvars
3958 resolve_error(self, span,
3959 ResolutionError::AttemptToUseNonConstantValueInConstant);
3966 Def::TyParam(..) | Def::SelfTy(..) => {
3969 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3970 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3971 ConstantItemRibKind => {
3972 // Nothing to do. Continue.
3975 // This was an attempt to use a type parameter outside
3978 resolve_error(self, span,
3979 ResolutionError::TypeParametersFromOuterFunction(def));
3991 fn lookup_assoc_candidate<FilterFn>(&mut self,
3994 filter_fn: FilterFn)
3995 -> Option<AssocSuggestion>
3996 where FilterFn: Fn(Def) -> bool
3998 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4000 TyKind::Path(None, _) => Some(t.id),
4001 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4002 // This doesn't handle the remaining `Ty` variants as they are not
4003 // that commonly the self_type, it might be interesting to provide
4004 // support for those in future.
4009 // Fields are generally expected in the same contexts as locals.
4010 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4011 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4012 // Look for a field with the same name in the current self_type.
4013 if let Some(resolution) = self.def_map.get(&node_id) {
4014 match resolution.base_def() {
4015 Def::Struct(did) | Def::Union(did)
4016 if resolution.unresolved_segments() == 0 => {
4017 if let Some(field_names) = self.field_names.get(&did) {
4018 if field_names.iter().any(|&field_name| ident.name == field_name) {
4019 return Some(AssocSuggestion::Field);
4029 // Look for associated items in the current trait.
4030 if let Some((module, _)) = self.current_trait_ref {
4031 if let Ok(binding) = self.resolve_ident_in_module(
4032 ModuleOrUniformRoot::Module(module),
4038 let def = binding.def();
4040 return Some(if self.has_self.contains(&def.def_id()) {
4041 AssocSuggestion::MethodWithSelf
4043 AssocSuggestion::AssocItem
4052 fn lookup_typo_candidate<FilterFn>(&mut self,
4055 filter_fn: FilterFn,
4058 where FilterFn: Fn(Def) -> bool
4060 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4061 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4062 if let Some(binding) = resolution.borrow().binding {
4063 if filter_fn(binding.def()) {
4064 names.push(ident.name);
4070 let mut names = Vec::new();
4071 if path.len() == 1 {
4072 // Search in lexical scope.
4073 // Walk backwards up the ribs in scope and collect candidates.
4074 for rib in self.ribs[ns].iter().rev() {
4075 // Locals and type parameters
4076 for (ident, def) in &rib.bindings {
4077 if filter_fn(*def) {
4078 names.push(ident.name);
4082 if let ModuleRibKind(module) = rib.kind {
4083 // Items from this module
4084 add_module_candidates(module, &mut names);
4086 if let ModuleKind::Block(..) = module.kind {
4087 // We can see through blocks
4089 // Items from the prelude
4090 if !module.no_implicit_prelude {
4091 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4092 if let Some(prelude) = self.prelude {
4093 add_module_candidates(prelude, &mut names);
4100 // Add primitive types to the mix
4101 if filter_fn(Def::PrimTy(Bool)) {
4103 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4107 // Search in module.
4108 let mod_path = &path[..path.len() - 1];
4109 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
4110 false, span, CrateLint::No) {
4111 if let ModuleOrUniformRoot::Module(module) = module {
4112 add_module_candidates(module, &mut names);
4117 let name = path[path.len() - 1].ident.name;
4118 // Make sure error reporting is deterministic.
4119 names.sort_by_cached_key(|name| name.as_str());
4120 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4121 Some(found) if found != name => Some(found),
4126 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4127 where F: FnOnce(&mut Resolver)
4129 if let Some(label) = label {
4130 self.unused_labels.insert(id, label.ident.span);
4131 let def = Def::Label(id);
4132 self.with_label_rib(|this| {
4133 let ident = label.ident.modern_and_legacy();
4134 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4142 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4143 self.with_resolved_label(label, id, |this| this.visit_block(block));
4146 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4147 // First, record candidate traits for this expression if it could
4148 // result in the invocation of a method call.
4150 self.record_candidate_traits_for_expr_if_necessary(expr);
4152 // Next, resolve the node.
4154 ExprKind::Path(ref qself, ref path) => {
4155 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4156 visit::walk_expr(self, expr);
4159 ExprKind::Struct(ref path, ..) => {
4160 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4161 visit::walk_expr(self, expr);
4164 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4165 let def = self.search_label(label.ident, |rib, ident| {
4166 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4170 // Search again for close matches...
4171 // Picks the first label that is "close enough", which is not necessarily
4172 // the closest match
4173 let close_match = self.search_label(label.ident, |rib, ident| {
4174 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4175 find_best_match_for_name(names, &*ident.as_str(), None)
4177 self.record_def(expr.id, err_path_resolution());
4180 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4183 Some(Def::Label(id)) => {
4184 // Since this def is a label, it is never read.
4185 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4186 self.unused_labels.remove(&id);
4189 span_bug!(expr.span, "label wasn't mapped to a label def!");
4193 // visit `break` argument if any
4194 visit::walk_expr(self, expr);
4197 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4198 self.visit_expr(subexpression);
4200 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4201 let mut bindings_list = FxHashMap::default();
4203 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4205 // This has to happen *after* we determine which pat_idents are variants
4206 self.check_consistent_bindings(pats);
4207 self.visit_block(if_block);
4208 self.ribs[ValueNS].pop();
4210 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4213 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4215 ExprKind::While(ref subexpression, ref block, label) => {
4216 self.with_resolved_label(label, expr.id, |this| {
4217 this.visit_expr(subexpression);
4218 this.visit_block(block);
4222 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4223 self.with_resolved_label(label, expr.id, |this| {
4224 this.visit_expr(subexpression);
4225 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4226 let mut bindings_list = FxHashMap::default();
4228 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4230 // This has to happen *after* we determine which pat_idents are variants
4231 this.check_consistent_bindings(pats);
4232 this.visit_block(block);
4233 this.ribs[ValueNS].pop();
4237 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4238 self.visit_expr(subexpression);
4239 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4240 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4242 self.resolve_labeled_block(label, expr.id, block);
4244 self.ribs[ValueNS].pop();
4247 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4249 // Equivalent to `visit::walk_expr` + passing some context to children.
4250 ExprKind::Field(ref subexpression, _) => {
4251 self.resolve_expr(subexpression, Some(expr));
4253 ExprKind::MethodCall(ref segment, ref arguments) => {
4254 let mut arguments = arguments.iter();
4255 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4256 for argument in arguments {
4257 self.resolve_expr(argument, None);
4259 self.visit_path_segment(expr.span, segment);
4262 ExprKind::Call(ref callee, ref arguments) => {
4263 self.resolve_expr(callee, Some(expr));
4264 for argument in arguments {
4265 self.resolve_expr(argument, None);
4268 ExprKind::Type(ref type_expr, _) => {
4269 self.current_type_ascription.push(type_expr.span);
4270 visit::walk_expr(self, expr);
4271 self.current_type_ascription.pop();
4273 // Resolve the body of async exprs inside the async closure to which they desugar
4274 ExprKind::Async(_, async_closure_id, ref block) => {
4275 let rib_kind = ClosureRibKind(async_closure_id);
4276 self.ribs[ValueNS].push(Rib::new(rib_kind));
4277 self.label_ribs.push(Rib::new(rib_kind));
4278 self.visit_block(&block);
4279 self.label_ribs.pop();
4280 self.ribs[ValueNS].pop();
4282 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4283 // resolve the arguments within the proper scopes so that usages of them inside the
4284 // closure are detected as upvars rather than normal closure arg usages.
4286 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4287 ref fn_decl, ref body, _span,
4289 let rib_kind = ClosureRibKind(expr.id);
4290 self.ribs[ValueNS].push(Rib::new(rib_kind));
4291 self.label_ribs.push(Rib::new(rib_kind));
4292 // Resolve arguments:
4293 let mut bindings_list = FxHashMap::default();
4294 for argument in &fn_decl.inputs {
4295 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4296 self.visit_ty(&argument.ty);
4298 // No need to resolve return type-- the outer closure return type is
4299 // FunctionRetTy::Default
4301 // Now resolve the inner closure
4303 let rib_kind = ClosureRibKind(inner_closure_id);
4304 self.ribs[ValueNS].push(Rib::new(rib_kind));
4305 self.label_ribs.push(Rib::new(rib_kind));
4306 // No need to resolve arguments: the inner closure has none.
4307 // Resolve the return type:
4308 visit::walk_fn_ret_ty(self, &fn_decl.output);
4310 self.visit_expr(body);
4311 self.label_ribs.pop();
4312 self.ribs[ValueNS].pop();
4314 self.label_ribs.pop();
4315 self.ribs[ValueNS].pop();
4318 visit::walk_expr(self, expr);
4323 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4325 ExprKind::Field(_, ident) => {
4326 // FIXME(#6890): Even though you can't treat a method like a
4327 // field, we need to add any trait methods we find that match
4328 // the field name so that we can do some nice error reporting
4329 // later on in typeck.
4330 let traits = self.get_traits_containing_item(ident, ValueNS);
4331 self.trait_map.insert(expr.id, traits);
4333 ExprKind::MethodCall(ref segment, ..) => {
4334 debug!("(recording candidate traits for expr) recording traits for {}",
4336 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4337 self.trait_map.insert(expr.id, traits);
4345 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4346 -> Vec<TraitCandidate> {
4347 debug!("(getting traits containing item) looking for '{}'", ident.name);
4349 let mut found_traits = Vec::new();
4350 // Look for the current trait.
4351 if let Some((module, _)) = self.current_trait_ref {
4352 if self.resolve_ident_in_module(
4353 ModuleOrUniformRoot::Module(module),
4359 let def_id = module.def_id().unwrap();
4360 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4364 ident.span = ident.span.modern();
4365 let mut search_module = self.current_module;
4367 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4368 search_module = unwrap_or!(
4369 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4373 if let Some(prelude) = self.prelude {
4374 if !search_module.no_implicit_prelude {
4375 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4382 fn get_traits_in_module_containing_item(&mut self,
4386 found_traits: &mut Vec<TraitCandidate>) {
4387 assert!(ns == TypeNS || ns == ValueNS);
4388 let mut traits = module.traits.borrow_mut();
4389 if traits.is_none() {
4390 let mut collected_traits = Vec::new();
4391 module.for_each_child(|name, ns, binding| {
4392 if ns != TypeNS { return }
4393 if let Def::Trait(_) = binding.def() {
4394 collected_traits.push((name, binding));
4397 *traits = Some(collected_traits.into_boxed_slice());
4400 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4401 let module = binding.module().unwrap();
4402 let mut ident = ident;
4403 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4406 if self.resolve_ident_in_module_unadjusted(
4407 ModuleOrUniformRoot::Module(module),
4414 let import_id = match binding.kind {
4415 NameBindingKind::Import { directive, .. } => {
4416 self.maybe_unused_trait_imports.insert(directive.id);
4417 self.add_to_glob_map(directive.id, trait_name);
4422 let trait_def_id = module.def_id().unwrap();
4423 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4428 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4430 namespace: Namespace,
4431 start_module: &'a ModuleData<'a>,
4433 filter_fn: FilterFn)
4434 -> Vec<ImportSuggestion>
4435 where FilterFn: Fn(Def) -> bool
4437 let mut candidates = Vec::new();
4438 let mut seen_modules = FxHashSet::default();
4439 let not_local_module = crate_name != keywords::Crate.ident();
4440 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4442 while let Some((in_module,
4444 in_module_is_extern)) = worklist.pop() {
4445 self.populate_module_if_necessary(in_module);
4447 // We have to visit module children in deterministic order to avoid
4448 // instabilities in reported imports (#43552).
4449 in_module.for_each_child_stable(|ident, ns, name_binding| {
4450 // avoid imports entirely
4451 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4452 // avoid non-importable candidates as well
4453 if !name_binding.is_importable() { return; }
4455 // collect results based on the filter function
4456 if ident.name == lookup_name && ns == namespace {
4457 if filter_fn(name_binding.def()) {
4459 let mut segms = path_segments.clone();
4460 if self.session.rust_2018() {
4461 // crate-local absolute paths start with `crate::` in edition 2018
4462 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4464 0, ast::PathSegment::from_ident(crate_name)
4468 segms.push(ast::PathSegment::from_ident(ident));
4470 span: name_binding.span,
4473 // the entity is accessible in the following cases:
4474 // 1. if it's defined in the same crate, it's always
4475 // accessible (since private entities can be made public)
4476 // 2. if it's defined in another crate, it's accessible
4477 // only if both the module is public and the entity is
4478 // declared as public (due to pruning, we don't explore
4479 // outside crate private modules => no need to check this)
4480 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4481 candidates.push(ImportSuggestion { path: path });
4486 // collect submodules to explore
4487 if let Some(module) = name_binding.module() {
4489 let mut path_segments = path_segments.clone();
4490 path_segments.push(ast::PathSegment::from_ident(ident));
4492 let is_extern_crate_that_also_appears_in_prelude =
4493 name_binding.is_extern_crate() &&
4494 self.session.rust_2018();
4496 let is_visible_to_user =
4497 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4499 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4500 // add the module to the lookup
4501 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4502 if seen_modules.insert(module.def_id().unwrap()) {
4503 worklist.push((module, path_segments, is_extern));
4513 /// When name resolution fails, this method can be used to look up candidate
4514 /// entities with the expected name. It allows filtering them using the
4515 /// supplied predicate (which should be used to only accept the types of
4516 /// definitions expected e.g. traits). The lookup spans across all crates.
4518 /// NOTE: The method does not look into imports, but this is not a problem,
4519 /// since we report the definitions (thus, the de-aliased imports).
4520 fn lookup_import_candidates<FilterFn>(&mut self,
4522 namespace: Namespace,
4523 filter_fn: FilterFn)
4524 -> Vec<ImportSuggestion>
4525 where FilterFn: Fn(Def) -> bool
4527 let mut suggestions = self.lookup_import_candidates_from_module(
4528 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4530 if self.session.rust_2018() {
4531 let extern_prelude_names = self.extern_prelude.clone();
4532 for (ident, _) in extern_prelude_names.into_iter() {
4533 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4535 let crate_root = self.get_module(DefId {
4537 index: CRATE_DEF_INDEX,
4539 self.populate_module_if_necessary(&crate_root);
4541 suggestions.extend(self.lookup_import_candidates_from_module(
4542 lookup_name, namespace, crate_root, ident, &filter_fn));
4550 fn find_module(&mut self,
4552 -> Option<(Module<'a>, ImportSuggestion)>
4554 let mut result = None;
4555 let mut seen_modules = FxHashSet::default();
4556 let mut worklist = vec![(self.graph_root, Vec::new())];
4558 while let Some((in_module, path_segments)) = worklist.pop() {
4559 // abort if the module is already found
4560 if result.is_some() { break; }
4562 self.populate_module_if_necessary(in_module);
4564 in_module.for_each_child_stable(|ident, _, name_binding| {
4565 // abort if the module is already found or if name_binding is private external
4566 if result.is_some() || !name_binding.vis.is_visible_locally() {
4569 if let Some(module) = name_binding.module() {
4571 let mut path_segments = path_segments.clone();
4572 path_segments.push(ast::PathSegment::from_ident(ident));
4573 if module.def() == Some(module_def) {
4575 span: name_binding.span,
4576 segments: path_segments,
4578 result = Some((module, ImportSuggestion { path: path }));
4580 // add the module to the lookup
4581 if seen_modules.insert(module.def_id().unwrap()) {
4582 worklist.push((module, path_segments));
4592 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4593 if let Def::Enum(..) = enum_def {} else {
4594 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4597 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4598 self.populate_module_if_necessary(enum_module);
4600 let mut variants = Vec::new();
4601 enum_module.for_each_child_stable(|ident, _, name_binding| {
4602 if let Def::Variant(..) = name_binding.def() {
4603 let mut segms = enum_import_suggestion.path.segments.clone();
4604 segms.push(ast::PathSegment::from_ident(ident));
4605 variants.push(Path {
4606 span: name_binding.span,
4615 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4616 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4617 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4618 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4622 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4624 ast::VisibilityKind::Public => ty::Visibility::Public,
4625 ast::VisibilityKind::Crate(..) => {
4626 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4628 ast::VisibilityKind::Inherited => {
4629 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4631 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4632 // Visibilities are resolved as global by default, add starting root segment.
4633 let segments = path.make_root().iter().chain(path.segments.iter())
4634 .map(|seg| Segment { ident: seg.ident, id: Some(seg.id) })
4635 .collect::<Vec<_>>();
4636 let def = self.smart_resolve_path_fragment(
4641 PathSource::Visibility,
4642 CrateLint::SimplePath(id),
4644 if def == Def::Err {
4645 ty::Visibility::Public
4647 let vis = ty::Visibility::Restricted(def.def_id());
4648 if self.is_accessible(vis) {
4651 self.session.span_err(path.span, "visibilities can only be restricted \
4652 to ancestor modules");
4653 ty::Visibility::Public
4660 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4661 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4664 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4665 vis.is_accessible_from(module.normal_ancestor_id, self)
4668 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4669 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4670 if !ptr::eq(module, old_module) {
4671 span_bug!(binding.span, "parent module is reset for binding");
4676 fn disambiguate_legacy_vs_modern(
4678 legacy: &'a NameBinding<'a>,
4679 modern: &'a NameBinding<'a>,
4681 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4682 // is disambiguated to mitigate regressions from macro modularization.
4683 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4684 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4685 self.binding_parent_modules.get(&PtrKey(modern))) {
4686 (Some(legacy), Some(modern)) =>
4687 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4688 modern.is_ancestor_of(legacy),
4693 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4694 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4696 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4698 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4699 let note = if b1.expansion != Mark::root() {
4700 Some(if let Def::Macro(..) = b1.def() {
4701 format!("macro-expanded {} do not shadow",
4702 if b1.is_import() { "macro imports" } else { "macros" })
4704 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4705 if b1.is_import() { "imports" } else { "items" })
4707 } else if b1.is_glob_import() {
4708 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4713 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4714 err.span_label(ident.span, "ambiguous name");
4715 err.span_note(b1.span, &msg1);
4717 Def::Macro(..) if b2.span.is_dummy() =>
4718 err.note(&format!("`{}` is also a builtin macro", ident)),
4719 _ => err.span_note(b2.span, &msg2),
4721 if let Some(note) = note {
4727 fn report_errors(&mut self, krate: &Crate) {
4728 self.report_with_use_injections(krate);
4729 let mut reported_spans = FxHashSet::default();
4731 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4732 let msg = "macro-expanded `macro_export` macros from the current crate \
4733 cannot be referred to by absolute paths";
4734 self.session.buffer_lint_with_diagnostic(
4735 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4736 CRATE_NODE_ID, span_use, msg,
4737 lint::builtin::BuiltinLintDiagnostics::
4738 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4742 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4743 if reported_spans.insert(ident.span) {
4744 self.report_ambiguity_error(ident, b1, b2);
4748 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4749 if !reported_spans.insert(span) { continue }
4750 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4754 fn report_with_use_injections(&mut self, krate: &Crate) {
4755 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4756 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4757 if !candidates.is_empty() {
4758 show_candidates(&mut err, span, &candidates, better, found_use);
4764 fn report_conflict<'b>(&mut self,
4768 new_binding: &NameBinding<'b>,
4769 old_binding: &NameBinding<'b>) {
4770 // Error on the second of two conflicting names
4771 if old_binding.span.lo() > new_binding.span.lo() {
4772 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4775 let container = match parent.kind {
4776 ModuleKind::Def(Def::Mod(_), _) => "module",
4777 ModuleKind::Def(Def::Trait(_), _) => "trait",
4778 ModuleKind::Block(..) => "block",
4782 let old_noun = match old_binding.is_import() {
4784 false => "definition",
4787 let new_participle = match new_binding.is_import() {
4792 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4794 if let Some(s) = self.name_already_seen.get(&name) {
4800 let old_kind = match (ns, old_binding.module()) {
4801 (ValueNS, _) => "value",
4802 (MacroNS, _) => "macro",
4803 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4804 (TypeNS, Some(module)) if module.is_normal() => "module",
4805 (TypeNS, Some(module)) if module.is_trait() => "trait",
4806 (TypeNS, _) => "type",
4809 let msg = format!("the name `{}` is defined multiple times", name);
4811 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4812 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4813 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4814 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4815 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4817 _ => match (old_binding.is_import(), new_binding.is_import()) {
4818 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4819 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4820 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4824 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4829 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4830 if !old_binding.span.is_dummy() {
4831 err.span_label(self.session.source_map().def_span(old_binding.span),
4832 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4835 // See https://github.com/rust-lang/rust/issues/32354
4836 if old_binding.is_import() || new_binding.is_import() {
4837 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4843 let cm = self.session.source_map();
4844 let rename_msg = "you can use `as` to change the binding name of the import";
4848 NameBindingKind::Import { directive, ..},
4851 cm.span_to_snippet(binding.span),
4852 binding.kind.clone(),
4853 binding.span.is_dummy(),
4855 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4856 format!("Other{}", name)
4858 format!("other_{}", name)
4861 err.span_suggestion_with_applicability(
4864 match (&directive.subclass, snippet.as_ref()) {
4865 (ImportDirectiveSubclass::SingleImport { .. }, "self") =>
4866 format!("self as {}", suggested_name),
4867 (ImportDirectiveSubclass::SingleImport { source, .. }, _) =>
4870 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
4872 if snippet.ends_with(";") {
4878 (ImportDirectiveSubclass::ExternCrate { source, target, .. }, _) =>
4880 "extern crate {} as {};",
4881 source.unwrap_or(target.name),
4884 (_, _) => unreachable!(),
4886 Applicability::MaybeIncorrect,
4889 err.span_label(binding.span, rename_msg);
4894 self.name_already_seen.insert(name, span);
4897 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool, skip_feature_gate: bool)
4898 -> Option<&'a NameBinding<'a>> {
4899 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
4900 if let Some(binding) = entry.extern_crate_item {
4901 if !speculative && !skip_feature_gate && entry.introduced_by_item &&
4902 !self.session.features_untracked().extern_crate_item_prelude {
4903 emit_feature_err(&self.session.parse_sess, "extern_crate_item_prelude",
4904 ident.span, GateIssue::Language,
4905 "use of extern prelude names introduced \
4906 with `extern crate` items is unstable");
4910 let crate_id = if !speculative {
4911 self.crate_loader.process_path_extern(ident.name, ident.span)
4912 } else if let Some(crate_id) =
4913 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
4918 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
4919 self.populate_module_if_necessary(&crate_root);
4920 Some((crate_root, ty::Visibility::Public, ident.span, Mark::root())
4921 .to_name_binding(self.arenas))
4927 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
4928 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfType.name()
4931 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
4932 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfValue.name()
4935 fn names_to_string(idents: &[Ident]) -> String {
4936 let mut result = String::new();
4937 for (i, ident) in idents.iter()
4938 .filter(|ident| ident.name != keywords::CrateRoot.name())
4941 result.push_str("::");
4943 result.push_str(&ident.as_str());
4948 fn path_names_to_string(path: &Path) -> String {
4949 names_to_string(&path.segments.iter()
4950 .map(|seg| seg.ident)
4951 .collect::<Vec<_>>())
4954 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4955 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4956 let variant_path = &suggestion.path;
4957 let variant_path_string = path_names_to_string(variant_path);
4959 let path_len = suggestion.path.segments.len();
4960 let enum_path = ast::Path {
4961 span: suggestion.path.span,
4962 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4964 let enum_path_string = path_names_to_string(&enum_path);
4966 (suggestion.path.span, variant_path_string, enum_path_string)
4970 /// When an entity with a given name is not available in scope, we search for
4971 /// entities with that name in all crates. This method allows outputting the
4972 /// results of this search in a programmer-friendly way
4973 fn show_candidates(err: &mut DiagnosticBuilder,
4974 // This is `None` if all placement locations are inside expansions
4976 candidates: &[ImportSuggestion],
4980 // we want consistent results across executions, but candidates are produced
4981 // by iterating through a hash map, so make sure they are ordered:
4982 let mut path_strings: Vec<_> =
4983 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4984 path_strings.sort();
4986 let better = if better { "better " } else { "" };
4987 let msg_diff = match path_strings.len() {
4988 1 => " is found in another module, you can import it",
4989 _ => "s are found in other modules, you can import them",
4991 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4993 if let Some(span) = span {
4994 for candidate in &mut path_strings {
4995 // produce an additional newline to separate the new use statement
4996 // from the directly following item.
4997 let additional_newline = if found_use {
5002 *candidate = format!("use {};\n{}", candidate, additional_newline);
5005 err.span_suggestions_with_applicability(
5009 Applicability::Unspecified,
5014 for candidate in path_strings {
5016 msg.push_str(&candidate);
5021 /// A somewhat inefficient routine to obtain the name of a module.
5022 fn module_to_string(module: Module) -> Option<String> {
5023 let mut names = Vec::new();
5025 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5026 if let ModuleKind::Def(_, name) = module.kind {
5027 if let Some(parent) = module.parent {
5028 names.push(Ident::with_empty_ctxt(name));
5029 collect_mod(names, parent);
5032 // danger, shouldn't be ident?
5033 names.push(Ident::from_str("<opaque>"));
5034 collect_mod(names, module.parent.unwrap());
5037 collect_mod(&mut names, module);
5039 if names.is_empty() {
5042 Some(names_to_string(&names.into_iter()
5044 .collect::<Vec<_>>()))
5047 fn err_path_resolution() -> PathResolution {
5048 PathResolution::new(Def::Err)
5051 #[derive(PartialEq,Copy, Clone)]
5052 pub enum MakeGlobMap {
5057 #[derive(Copy, Clone, Debug)]
5059 /// Do not issue the lint
5062 /// This lint applies to some random path like `impl ::foo::Bar`
5063 /// or whatever. In this case, we can take the span of that path.
5066 /// This lint comes from a `use` statement. In this case, what we
5067 /// care about really is the *root* `use` statement; e.g., if we
5068 /// have nested things like `use a::{b, c}`, we care about the
5070 UsePath { root_id: NodeId, root_span: Span },
5072 /// This is the "trait item" from a fully qualified path. For example,
5073 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5074 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5075 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5079 fn node_id(&self) -> Option<NodeId> {
5081 CrateLint::No => None,
5082 CrateLint::SimplePath(id) |
5083 CrateLint::UsePath { root_id: id, .. } |
5084 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5089 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }