1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
16 #![feature(label_break_value)]
18 #![feature(rustc_diagnostic_macros)]
19 #![feature(slice_sort_by_cached_key)]
22 extern crate bitflags;
27 extern crate syntax_pos;
28 extern crate rustc_errors as errors;
32 extern crate rustc_data_structures;
33 extern crate rustc_metadata;
35 pub use rustc::hir::def::{Namespace, PerNS};
37 use self::TypeParameters::*;
40 use rustc::hir::map::{Definitions, DefCollector};
41 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
42 use rustc::middle::cstore::CrateStore;
43 use rustc::session::Session;
45 use rustc::hir::def::*;
46 use rustc::hir::def::Namespace::*;
47 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
48 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
49 use rustc::session::config::nightly_options;
51 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
53 use rustc_metadata::creader::CrateLoader;
54 use rustc_metadata::cstore::CStore;
56 use syntax::source_map::SourceMap;
57 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
58 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
59 use syntax::ext::base::SyntaxExtension;
60 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
61 use syntax::ext::base::MacroKind;
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())
111 /// A free importable items suggested in case of resolution failure.
112 struct ImportSuggestion {
116 /// A field or associated item from self type suggested in case of resolution failure.
117 enum AssocSuggestion {
124 struct BindingError {
126 origin: BTreeSet<Span>,
127 target: BTreeSet<Span>,
130 impl PartialOrd for BindingError {
131 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
132 Some(self.cmp(other))
136 impl PartialEq for BindingError {
137 fn eq(&self, other: &BindingError) -> bool {
138 self.name == other.name
142 impl Ord for BindingError {
143 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
144 self.name.cmp(&other.name)
148 enum ResolutionError<'a> {
149 /// error E0401: can't use type parameters from outer function
150 TypeParametersFromOuterFunction(Def),
151 /// error E0403: the name is already used for a type parameter in this type parameter list
152 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
153 /// error E0407: method is not a member of trait
154 MethodNotMemberOfTrait(Name, &'a str),
155 /// error E0437: type is not a member of trait
156 TypeNotMemberOfTrait(Name, &'a str),
157 /// error E0438: const is not a member of trait
158 ConstNotMemberOfTrait(Name, &'a str),
159 /// error E0408: variable `{}` is not bound in all patterns
160 VariableNotBoundInPattern(&'a BindingError),
161 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
162 VariableBoundWithDifferentMode(Name, Span),
163 /// error E0415: identifier is bound more than once in this parameter list
164 IdentifierBoundMoreThanOnceInParameterList(&'a str),
165 /// error E0416: identifier is bound more than once in the same pattern
166 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
167 /// error E0426: use of undeclared label
168 UndeclaredLabel(&'a str, Option<Name>),
169 /// error E0429: `self` imports are only allowed within a { } list
170 SelfImportsOnlyAllowedWithin,
171 /// error E0430: `self` import can only appear once in the list
172 SelfImportCanOnlyAppearOnceInTheList,
173 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
174 SelfImportOnlyInImportListWithNonEmptyPrefix,
175 /// error E0433: failed to resolve
176 FailedToResolve(&'a str),
177 /// error E0434: can't capture dynamic environment in a fn item
178 CannotCaptureDynamicEnvironmentInFnItem,
179 /// error E0435: attempt to use a non-constant value in a constant
180 AttemptToUseNonConstantValueInConstant,
181 /// error E0530: X bindings cannot shadow Ys
182 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
183 /// error E0128: type parameters with a default cannot use forward declared identifiers
184 ForwardDeclaredTyParam,
187 /// Combines an error with provided span and emits it
189 /// This takes the error provided, combines it with the span and any additional spans inside the
190 /// error and emits it.
191 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
193 resolution_error: ResolutionError<'a>) {
194 resolve_struct_error(resolver, span, resolution_error).emit();
197 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
199 resolution_error: ResolutionError<'a>)
200 -> DiagnosticBuilder<'sess> {
201 match resolution_error {
202 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
203 let mut err = struct_span_err!(resolver.session,
206 "can't use type parameters from outer function");
207 err.span_label(span, "use of type variable from outer function");
209 let cm = resolver.session.source_map();
211 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
212 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
213 resolver.definitions.opt_span(def_id)
216 reduce_impl_span_to_impl_keyword(cm, impl_span),
217 "`Self` type implicitly declared here, by this `impl`",
220 match (maybe_trait_defid, maybe_impl_defid) {
222 err.span_label(span, "can't use `Self` here");
225 err.span_label(span, "use a type here instead");
227 (None, None) => bug!("`impl` without trait nor type?"),
231 Def::TyParam(typaram_defid) => {
232 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
233 err.span_label(typaram_span, "type variable from outer function");
237 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
242 // Try to retrieve the span of the function signature and generate a new message with
243 // a local type parameter
244 let sugg_msg = "try using a local type parameter instead";
245 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
246 // Suggest the modification to the user
247 err.span_suggestion_with_applicability(
251 Applicability::MachineApplicable,
253 } else if let Some(sp) = cm.generate_fn_name_span(span) {
254 err.span_label(sp, "try adding a local type parameter in this method instead");
256 err.help("try using a local type parameter instead");
261 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
262 let mut err = struct_span_err!(resolver.session,
265 "the name `{}` is already used for a type parameter \
266 in this type parameter list",
268 err.span_label(span, "already used");
269 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
272 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
273 let mut err = struct_span_err!(resolver.session,
276 "method `{}` is not a member of trait `{}`",
279 err.span_label(span, format!("not a member of trait `{}`", trait_));
282 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
283 let mut err = struct_span_err!(resolver.session,
286 "type `{}` is not a member of trait `{}`",
289 err.span_label(span, format!("not a member of trait `{}`", trait_));
292 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
293 let mut err = struct_span_err!(resolver.session,
296 "const `{}` is not a member of trait `{}`",
299 err.span_label(span, format!("not a member of trait `{}`", trait_));
302 ResolutionError::VariableNotBoundInPattern(binding_error) => {
303 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
304 let msp = MultiSpan::from_spans(target_sp.clone());
305 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
306 let mut err = resolver.session.struct_span_err_with_code(
309 DiagnosticId::Error("E0408".into()),
311 for sp in target_sp {
312 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
314 let origin_sp = binding_error.origin.iter().cloned();
315 for sp in origin_sp {
316 err.span_label(sp, "variable not in all patterns");
320 ResolutionError::VariableBoundWithDifferentMode(variable_name,
321 first_binding_span) => {
322 let mut err = struct_span_err!(resolver.session,
325 "variable `{}` is bound in inconsistent \
326 ways within the same match arm",
328 err.span_label(span, "bound in different ways");
329 err.span_label(first_binding_span, "first binding");
332 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
333 let mut err = struct_span_err!(resolver.session,
336 "identifier `{}` is bound more than once in this parameter list",
338 err.span_label(span, "used as parameter more than once");
341 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
342 let mut err = struct_span_err!(resolver.session,
345 "identifier `{}` is bound more than once in the same pattern",
347 err.span_label(span, "used in a pattern more than once");
350 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
351 let mut err = struct_span_err!(resolver.session,
354 "use of undeclared label `{}`",
356 if let Some(lev_candidate) = lev_candidate {
357 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
359 err.span_label(span, format!("undeclared label `{}`", name));
363 ResolutionError::SelfImportsOnlyAllowedWithin => {
364 struct_span_err!(resolver.session,
368 "`self` imports are only allowed within a { } list")
370 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
371 let mut err = struct_span_err!(resolver.session, span, E0430,
372 "`self` import can only appear once in an import list");
373 err.span_label(span, "can only appear once in an import list");
376 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
377 let mut err = struct_span_err!(resolver.session, span, E0431,
378 "`self` import can only appear in an import list with \
379 a non-empty prefix");
380 err.span_label(span, "can only appear in an import list with a non-empty prefix");
383 ResolutionError::FailedToResolve(msg) => {
384 let mut err = struct_span_err!(resolver.session, span, E0433,
385 "failed to resolve: {}", msg);
386 err.span_label(span, msg);
389 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
390 let mut err = struct_span_err!(resolver.session,
394 "can't capture dynamic environment in a fn item");
395 err.help("use the `|| { ... }` closure form instead");
398 ResolutionError::AttemptToUseNonConstantValueInConstant => {
399 let mut err = struct_span_err!(resolver.session, span, E0435,
400 "attempt to use a non-constant value in a constant");
401 err.span_label(span, "non-constant value");
404 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
405 let shadows_what = binding.descr();
406 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
407 what_binding, shadows_what);
408 err.span_label(span, format!("cannot be named the same as {} {}",
409 binding.article(), shadows_what));
410 let participle = if binding.is_import() { "imported" } else { "defined" };
411 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
412 err.span_label(binding.span, msg);
415 ResolutionError::ForwardDeclaredTyParam => {
416 let mut err = struct_span_err!(resolver.session, span, E0128,
417 "type parameters with a default cannot use \
418 forward declared identifiers");
420 span, "defaulted type parameters cannot be forward declared".to_string());
426 /// Adjust the impl span so that just the `impl` keyword is taken by removing
427 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
428 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
430 /// Attention: The method used is very fragile since it essentially duplicates the work of the
431 /// parser. If you need to use this function or something similar, please consider updating the
432 /// source_map functions and this function to something more robust.
433 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
434 let impl_span = cm.span_until_char(impl_span, '<');
435 let impl_span = cm.span_until_whitespace(impl_span);
439 #[derive(Copy, Clone, Debug)]
442 binding_mode: BindingMode,
445 /// Map from the name in a pattern to its binding mode.
446 type BindingMap = FxHashMap<Ident, BindingInfo>;
448 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
459 fn descr(self) -> &'static str {
461 PatternSource::Match => "match binding",
462 PatternSource::IfLet => "if let binding",
463 PatternSource::WhileLet => "while let binding",
464 PatternSource::Let => "let binding",
465 PatternSource::For => "for binding",
466 PatternSource::FnParam => "function parameter",
471 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
472 enum AliasPossibility {
477 #[derive(Copy, Clone, Debug)]
478 enum PathSource<'a> {
479 // Type paths `Path`.
481 // Trait paths in bounds or impls.
482 Trait(AliasPossibility),
483 // Expression paths `path`, with optional parent context.
484 Expr(Option<&'a Expr>),
485 // Paths in path patterns `Path`.
487 // Paths in struct expressions and patterns `Path { .. }`.
489 // Paths in tuple struct patterns `Path(..)`.
491 // `m::A::B` in `<T as m::A>::B::C`.
492 TraitItem(Namespace),
493 // Path in `pub(path)`
497 impl<'a> PathSource<'a> {
498 fn namespace(self) -> Namespace {
500 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
501 PathSource::Visibility => TypeNS,
502 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
503 PathSource::TraitItem(ns) => ns,
507 fn global_by_default(self) -> bool {
509 PathSource::Visibility => true,
510 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
511 PathSource::Struct | PathSource::TupleStruct |
512 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
516 fn defer_to_typeck(self) -> bool {
518 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
519 PathSource::Struct | PathSource::TupleStruct => true,
520 PathSource::Trait(_) | PathSource::TraitItem(..) |
521 PathSource::Visibility => false,
525 fn descr_expected(self) -> &'static str {
527 PathSource::Type => "type",
528 PathSource::Trait(_) => "trait",
529 PathSource::Pat => "unit struct/variant or constant",
530 PathSource::Struct => "struct, variant or union type",
531 PathSource::TupleStruct => "tuple struct/variant",
532 PathSource::Visibility => "module",
533 PathSource::TraitItem(ns) => match ns {
534 TypeNS => "associated type",
535 ValueNS => "method or associated constant",
536 MacroNS => bug!("associated macro"),
538 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
539 // "function" here means "anything callable" rather than `Def::Fn`,
540 // this is not precise but usually more helpful than just "value".
541 Some(&ExprKind::Call(..)) => "function",
547 fn is_expected(self, def: Def) -> bool {
549 PathSource::Type => match def {
550 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
551 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
552 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
553 Def::SelfTy(..) | Def::Existential(..) |
554 Def::ForeignTy(..) => true,
557 PathSource::Trait(AliasPossibility::No) => match def {
558 Def::Trait(..) => true,
561 PathSource::Trait(AliasPossibility::Maybe) => match def {
562 Def::Trait(..) => true,
563 Def::TraitAlias(..) => true,
566 PathSource::Expr(..) => match def {
567 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
568 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
569 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
570 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
571 Def::SelfCtor(..) => true,
574 PathSource::Pat => match def {
575 Def::StructCtor(_, CtorKind::Const) |
576 Def::VariantCtor(_, CtorKind::Const) |
577 Def::Const(..) | Def::AssociatedConst(..) |
578 Def::SelfCtor(..) => true,
581 PathSource::TupleStruct => match def {
582 Def::StructCtor(_, CtorKind::Fn) |
583 Def::VariantCtor(_, CtorKind::Fn) |
584 Def::SelfCtor(..) => true,
587 PathSource::Struct => match def {
588 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
589 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
592 PathSource::TraitItem(ns) => match def {
593 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
594 Def::AssociatedTy(..) if ns == TypeNS => true,
597 PathSource::Visibility => match def {
598 Def::Mod(..) => true,
604 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
605 __diagnostic_used!(E0404);
606 __diagnostic_used!(E0405);
607 __diagnostic_used!(E0412);
608 __diagnostic_used!(E0422);
609 __diagnostic_used!(E0423);
610 __diagnostic_used!(E0425);
611 __diagnostic_used!(E0531);
612 __diagnostic_used!(E0532);
613 __diagnostic_used!(E0573);
614 __diagnostic_used!(E0574);
615 __diagnostic_used!(E0575);
616 __diagnostic_used!(E0576);
617 __diagnostic_used!(E0577);
618 __diagnostic_used!(E0578);
619 match (self, has_unexpected_resolution) {
620 (PathSource::Trait(_), true) => "E0404",
621 (PathSource::Trait(_), false) => "E0405",
622 (PathSource::Type, true) => "E0573",
623 (PathSource::Type, false) => "E0412",
624 (PathSource::Struct, true) => "E0574",
625 (PathSource::Struct, false) => "E0422",
626 (PathSource::Expr(..), true) => "E0423",
627 (PathSource::Expr(..), false) => "E0425",
628 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
629 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
630 (PathSource::TraitItem(..), true) => "E0575",
631 (PathSource::TraitItem(..), false) => "E0576",
632 (PathSource::Visibility, true) => "E0577",
633 (PathSource::Visibility, false) => "E0578",
638 // A minimal representation of a path segment. We use this in resolve because
639 // we synthesize 'path segments' which don't have the rest of an AST or HIR
641 #[derive(Clone, Copy, Debug)]
648 fn from_path(path: &Path) -> Vec<Segment> {
649 path.segments.iter().map(|s| s.into()).collect()
652 fn from_ident(ident: Ident) -> Segment {
659 fn names_to_string(segments: &[Segment]) -> String {
660 names_to_string(&segments.iter()
661 .map(|seg| seg.ident)
662 .collect::<Vec<_>>())
666 impl<'a> From<&'a ast::PathSegment> for Segment {
667 fn from(seg: &'a ast::PathSegment) -> Segment {
675 struct UsePlacementFinder {
676 target_module: NodeId,
681 impl UsePlacementFinder {
682 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
683 let mut finder = UsePlacementFinder {
688 visit::walk_crate(&mut finder, krate);
689 (finder.span, finder.found_use)
693 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
696 module: &'tcx ast::Mod,
698 _: &[ast::Attribute],
701 if self.span.is_some() {
704 if node_id != self.target_module {
705 visit::walk_mod(self, module);
708 // find a use statement
709 for item in &module.items {
711 ItemKind::Use(..) => {
712 // don't suggest placing a use before the prelude
713 // import or other generated ones
714 if item.span.ctxt().outer().expn_info().is_none() {
715 self.span = Some(item.span.shrink_to_lo());
716 self.found_use = true;
720 // don't place use before extern crate
721 ItemKind::ExternCrate(_) => {}
722 // but place them before the first other item
723 _ => if self.span.map_or(true, |span| item.span < span ) {
724 if item.span.ctxt().outer().expn_info().is_none() {
725 // don't insert between attributes and an item
726 if item.attrs.is_empty() {
727 self.span = Some(item.span.shrink_to_lo());
729 // find the first attribute on the item
730 for attr in &item.attrs {
731 if self.span.map_or(true, |span| attr.span < span) {
732 self.span = Some(attr.span.shrink_to_lo());
743 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
744 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
745 fn visit_item(&mut self, item: &'tcx Item) {
746 self.resolve_item(item);
748 fn visit_arm(&mut self, arm: &'tcx Arm) {
749 self.resolve_arm(arm);
751 fn visit_block(&mut self, block: &'tcx Block) {
752 self.resolve_block(block);
754 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
755 self.with_constant_rib(|this| {
756 visit::walk_anon_const(this, constant);
759 fn visit_expr(&mut self, expr: &'tcx Expr) {
760 self.resolve_expr(expr, None);
762 fn visit_local(&mut self, local: &'tcx Local) {
763 self.resolve_local(local);
765 fn visit_ty(&mut self, ty: &'tcx Ty) {
767 TyKind::Path(ref qself, ref path) => {
768 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
770 TyKind::ImplicitSelf => {
771 let self_ty = keywords::SelfType.ident();
772 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
773 .map_or(Def::Err, |d| d.def());
774 self.record_def(ty.id, PathResolution::new(def));
778 visit::walk_ty(self, ty);
780 fn visit_poly_trait_ref(&mut self,
781 tref: &'tcx ast::PolyTraitRef,
782 m: &'tcx ast::TraitBoundModifier) {
783 self.smart_resolve_path(tref.trait_ref.ref_id, None,
784 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
785 visit::walk_poly_trait_ref(self, tref, m);
787 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
788 let type_parameters = match foreign_item.node {
789 ForeignItemKind::Fn(_, ref generics) => {
790 HasTypeParameters(generics, ItemRibKind)
792 ForeignItemKind::Static(..) => NoTypeParameters,
793 ForeignItemKind::Ty => NoTypeParameters,
794 ForeignItemKind::Macro(..) => NoTypeParameters,
796 self.with_type_parameter_rib(type_parameters, |this| {
797 visit::walk_foreign_item(this, foreign_item);
800 fn visit_fn(&mut self,
801 function_kind: FnKind<'tcx>,
802 declaration: &'tcx FnDecl,
806 let (rib_kind, asyncness) = match function_kind {
807 FnKind::ItemFn(_, ref header, ..) =>
808 (ItemRibKind, header.asyncness),
809 FnKind::Method(_, ref sig, _, _) =>
810 (TraitOrImplItemRibKind, sig.header.asyncness),
811 FnKind::Closure(_) =>
812 // Async closures aren't resolved through `visit_fn`-- they're
813 // processed separately
814 (ClosureRibKind(node_id), IsAsync::NotAsync),
817 // Create a value rib for the function.
818 self.ribs[ValueNS].push(Rib::new(rib_kind));
820 // Create a label rib for the function.
821 self.label_ribs.push(Rib::new(rib_kind));
823 // Add each argument to the rib.
824 let mut bindings_list = FxHashMap::default();
825 for argument in &declaration.inputs {
826 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
828 self.visit_ty(&argument.ty);
830 debug!("(resolving function) recorded argument");
832 visit::walk_fn_ret_ty(self, &declaration.output);
834 // Resolve the function body, potentially inside the body of an async closure
835 if let IsAsync::Async { closure_id, .. } = asyncness {
836 let rib_kind = ClosureRibKind(closure_id);
837 self.ribs[ValueNS].push(Rib::new(rib_kind));
838 self.label_ribs.push(Rib::new(rib_kind));
841 match function_kind {
842 FnKind::ItemFn(.., body) |
843 FnKind::Method(.., body) => {
844 self.visit_block(body);
846 FnKind::Closure(body) => {
847 self.visit_expr(body);
851 // Leave the body of the async closure
852 if asyncness.is_async() {
853 self.label_ribs.pop();
854 self.ribs[ValueNS].pop();
857 debug!("(resolving function) leaving function");
859 self.label_ribs.pop();
860 self.ribs[ValueNS].pop();
862 fn visit_generics(&mut self, generics: &'tcx Generics) {
863 // For type parameter defaults, we have to ban access
864 // to following type parameters, as the Substs can only
865 // provide previous type parameters as they're built. We
866 // put all the parameters on the ban list and then remove
867 // them one by one as they are processed and become available.
868 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
869 let mut found_default = false;
870 default_ban_rib.bindings.extend(generics.params.iter()
871 .filter_map(|param| match param.kind {
872 GenericParamKind::Lifetime { .. } => None,
873 GenericParamKind::Type { ref default, .. } => {
874 found_default |= default.is_some();
876 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
883 for param in &generics.params {
885 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
886 GenericParamKind::Type { ref default, .. } => {
887 for bound in ¶m.bounds {
888 self.visit_param_bound(bound);
891 if let Some(ref ty) = default {
892 self.ribs[TypeNS].push(default_ban_rib);
894 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
897 // Allow all following defaults to refer to this type parameter.
898 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
902 for p in &generics.where_clause.predicates {
903 self.visit_where_predicate(p);
908 #[derive(Copy, Clone)]
909 enum TypeParameters<'a, 'b> {
911 HasTypeParameters(// Type parameters.
914 // The kind of the rib used for type parameters.
918 /// The rib kind controls the translation of local
919 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
920 #[derive(Copy, Clone, Debug)]
922 /// No translation needs to be applied.
925 /// We passed through a closure scope at the given node ID.
926 /// Translate upvars as appropriate.
927 ClosureRibKind(NodeId /* func id */),
929 /// We passed through an impl or trait and are now in one of its
930 /// methods or associated types. Allow references to ty params that impl or trait
931 /// binds. Disallow any other upvars (including other ty params that are
933 TraitOrImplItemRibKind,
935 /// We passed through an item scope. Disallow upvars.
938 /// We're in a constant item. Can't refer to dynamic stuff.
941 /// We passed through a module.
942 ModuleRibKind(Module<'a>),
944 /// We passed through a `macro_rules!` statement
945 MacroDefinition(DefId),
947 /// All bindings in this rib are type parameters that can't be used
948 /// from the default of a type parameter because they're not declared
949 /// before said type parameter. Also see the `visit_generics` override.
950 ForwardTyParamBanRibKind,
955 /// A rib represents a scope names can live in. Note that these appear in many places, not just
956 /// around braces. At any place where the list of accessible names (of the given namespace)
957 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
958 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
961 /// Different [rib kinds](enum.RibKind) are transparent for different names.
963 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
964 /// resolving, the name is looked up from inside out.
967 bindings: FxHashMap<Ident, Def>,
972 fn new(kind: RibKind<'a>) -> Rib<'a> {
974 bindings: Default::default(),
980 /// An intermediate resolution result.
982 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
983 /// items are visible in their whole block, while defs only from the place they are defined
985 enum LexicalScopeBinding<'a> {
986 Item(&'a NameBinding<'a>),
990 impl<'a> LexicalScopeBinding<'a> {
991 fn item(self) -> Option<&'a NameBinding<'a>> {
993 LexicalScopeBinding::Item(binding) => Some(binding),
998 fn def(self) -> Def {
1000 LexicalScopeBinding::Item(binding) => binding.def(),
1001 LexicalScopeBinding::Def(def) => def,
1006 #[derive(Copy, Clone, Debug)]
1007 enum ModuleOrUniformRoot<'a> {
1011 /// Virtual module that denotes resolution in extern prelude.
1012 /// Used for paths starting with `::` on 2018 edition or `extern::`.
1015 /// Virtual module that denotes resolution in current scope.
1016 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1017 /// are always split into two parts, the first of which should be some kind of module.
1021 impl<'a> PartialEq for ModuleOrUniformRoot<'a> {
1022 fn eq(&self, other: &Self) -> bool {
1023 match (*self, *other) {
1024 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) =>
1026 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) => true,
1027 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1033 #[derive(Clone, Debug)]
1034 enum PathResult<'a> {
1035 Module(ModuleOrUniformRoot<'a>),
1036 NonModule(PathResolution),
1038 Failed(Span, String, bool /* is the error from the last segment? */),
1042 /// An anonymous module, eg. just a block.
1046 /// fn f() {} // (1)
1047 /// { // This is an anonymous module
1048 /// f(); // This resolves to (2) as we are inside the block.
1049 /// fn f() {} // (2)
1051 /// f(); // Resolves to (1)
1055 /// Any module with a name.
1059 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1060 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1065 /// One node in the tree of modules.
1066 pub struct ModuleData<'a> {
1067 parent: Option<Module<'a>>,
1070 // The def id of the closest normal module (`mod`) ancestor (including this module).
1071 normal_ancestor_id: DefId,
1073 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1074 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1075 Option<&'a NameBinding<'a>>)>>,
1076 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1078 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1080 // Macro invocations that can expand into items in this module.
1081 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1083 no_implicit_prelude: bool,
1085 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1086 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1088 // Used to memoize the traits in this module for faster searches through all traits in scope.
1089 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1091 // Whether this module is populated. If not populated, any attempt to
1092 // access the children must be preceded with a
1093 // `populate_module_if_necessary` call.
1094 populated: Cell<bool>,
1096 /// Span of the module itself. Used for error reporting.
1102 type Module<'a> = &'a ModuleData<'a>;
1104 impl<'a> ModuleData<'a> {
1105 fn new(parent: Option<Module<'a>>,
1107 normal_ancestor_id: DefId,
1109 span: Span) -> Self {
1114 resolutions: Default::default(),
1115 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1116 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1117 builtin_attrs: RefCell::new(Vec::new()),
1118 unresolved_invocations: Default::default(),
1119 no_implicit_prelude: false,
1120 glob_importers: RefCell::new(Vec::new()),
1121 globs: RefCell::new(Vec::new()),
1122 traits: RefCell::new(None),
1123 populated: Cell::new(normal_ancestor_id.is_local()),
1129 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1130 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1131 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1135 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1136 let resolutions = self.resolutions.borrow();
1137 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1138 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1139 for &(&(ident, ns), &resolution) in resolutions.iter() {
1140 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1144 fn def(&self) -> Option<Def> {
1146 ModuleKind::Def(def, _) => Some(def),
1151 fn def_id(&self) -> Option<DefId> {
1152 self.def().as_ref().map(Def::def_id)
1155 // `self` resolves to the first module ancestor that `is_normal`.
1156 fn is_normal(&self) -> bool {
1158 ModuleKind::Def(Def::Mod(_), _) => true,
1163 fn is_trait(&self) -> bool {
1165 ModuleKind::Def(Def::Trait(_), _) => true,
1170 fn is_local(&self) -> bool {
1171 self.normal_ancestor_id.is_local()
1174 fn nearest_item_scope(&'a self) -> Module<'a> {
1175 if self.is_trait() { self.parent.unwrap() } else { self }
1178 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1179 while !ptr::eq(self, other) {
1180 if let Some(parent) = other.parent {
1190 impl<'a> fmt::Debug for ModuleData<'a> {
1191 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1192 write!(f, "{:?}", self.def())
1196 /// Records a possibly-private value, type, or module definition.
1197 #[derive(Clone, Debug)]
1198 pub struct NameBinding<'a> {
1199 kind: NameBindingKind<'a>,
1202 vis: ty::Visibility,
1205 pub trait ToNameBinding<'a> {
1206 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1209 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1210 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1215 #[derive(Clone, Debug)]
1216 enum NameBindingKind<'a> {
1217 Def(Def, /* is_macro_export */ bool),
1220 binding: &'a NameBinding<'a>,
1221 directive: &'a ImportDirective<'a>,
1225 kind: AmbiguityKind,
1226 b1: &'a NameBinding<'a>,
1227 b2: &'a NameBinding<'a>,
1231 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1233 struct UseError<'a> {
1234 err: DiagnosticBuilder<'a>,
1235 /// Attach `use` statements for these candidates
1236 candidates: Vec<ImportSuggestion>,
1237 /// The node id of the module to place the use statements in
1239 /// Whether the diagnostic should state that it's "better"
1243 #[derive(Clone, Copy, PartialEq, Debug)]
1244 enum AmbiguityKind {
1248 LegacyHelperVsPrelude,
1253 MoreExpandedVsOuter,
1256 impl AmbiguityKind {
1257 fn descr(self) -> &'static str {
1259 AmbiguityKind::Import =>
1260 "name vs any other name during import resolution",
1261 AmbiguityKind::BuiltinAttr =>
1262 "built-in attribute vs any other name",
1263 AmbiguityKind::DeriveHelper =>
1264 "derive helper attribute vs any other name",
1265 AmbiguityKind::LegacyHelperVsPrelude =>
1266 "legacy plugin helper attribute vs name from prelude",
1267 AmbiguityKind::LegacyVsModern =>
1268 "`macro_rules` vs non-`macro_rules` from other module",
1269 AmbiguityKind::GlobVsOuter =>
1270 "glob import vs any other name from outer scope during import/macro resolution",
1271 AmbiguityKind::GlobVsGlob =>
1272 "glob import vs glob import in the same module",
1273 AmbiguityKind::GlobVsExpanded =>
1274 "glob import vs macro-expanded name in the same \
1275 module during import/macro resolution",
1276 AmbiguityKind::MoreExpandedVsOuter =>
1277 "macro-expanded name vs less macro-expanded name \
1278 from outer scope during import/macro resolution",
1283 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1284 #[derive(Clone, Copy, PartialEq)]
1285 enum AmbiguityErrorMisc {
1291 struct AmbiguityError<'a> {
1292 kind: AmbiguityKind,
1294 b1: &'a NameBinding<'a>,
1295 b2: &'a NameBinding<'a>,
1296 misc1: AmbiguityErrorMisc,
1297 misc2: AmbiguityErrorMisc,
1300 impl<'a> NameBinding<'a> {
1301 fn module(&self) -> Option<Module<'a>> {
1303 NameBindingKind::Module(module) => Some(module),
1304 NameBindingKind::Import { binding, .. } => binding.module(),
1309 fn def(&self) -> Def {
1311 NameBindingKind::Def(def, _) => def,
1312 NameBindingKind::Module(module) => module.def().unwrap(),
1313 NameBindingKind::Import { binding, .. } => binding.def(),
1314 NameBindingKind::Ambiguity { .. } => Def::Err,
1318 fn def_ignoring_ambiguity(&self) -> Def {
1320 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1321 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1326 // We sometimes need to treat variants as `pub` for backwards compatibility
1327 fn pseudo_vis(&self) -> ty::Visibility {
1328 if self.is_variant() && self.def().def_id().is_local() {
1329 ty::Visibility::Public
1335 fn is_variant(&self) -> bool {
1337 NameBindingKind::Def(Def::Variant(..), _) |
1338 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1343 fn is_extern_crate(&self) -> bool {
1345 NameBindingKind::Import {
1346 directive: &ImportDirective {
1347 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1350 NameBindingKind::Module(
1351 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1352 ) => def_id.index == CRATE_DEF_INDEX,
1357 fn is_import(&self) -> bool {
1359 NameBindingKind::Import { .. } => true,
1364 fn is_glob_import(&self) -> bool {
1366 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1367 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1372 fn is_importable(&self) -> bool {
1374 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1379 fn is_macro_def(&self) -> bool {
1381 NameBindingKind::Def(Def::Macro(..), _) => true,
1386 fn macro_kind(&self) -> Option<MacroKind> {
1387 match self.def_ignoring_ambiguity() {
1388 Def::Macro(_, kind) => Some(kind),
1389 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1394 fn descr(&self) -> &'static str {
1395 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1398 fn article(&self) -> &'static str {
1399 if self.is_extern_crate() { "an" } else { self.def().article() }
1402 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1403 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1404 // Then this function returns `true` if `self` may emerge from a macro *after* that
1405 // in some later round and screw up our previously found resolution.
1406 // See more detailed explanation in
1407 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1408 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1409 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1410 // Expansions are partially ordered, so "may appear after" is an inversion of
1411 // "certainly appears before or simultaneously" and includes unordered cases.
1412 let self_parent_expansion = self.expansion;
1413 let other_parent_expansion = binding.expansion;
1414 let certainly_before_other_or_simultaneously =
1415 other_parent_expansion.is_descendant_of(self_parent_expansion);
1416 let certainly_before_invoc_or_simultaneously =
1417 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1418 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1422 /// Interns the names of the primitive types.
1424 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1425 /// special handling, since they have no place of origin.
1427 struct PrimitiveTypeTable {
1428 primitive_types: FxHashMap<Name, PrimTy>,
1431 impl PrimitiveTypeTable {
1432 fn new() -> PrimitiveTypeTable {
1433 let mut table = PrimitiveTypeTable::default();
1435 table.intern("bool", Bool);
1436 table.intern("char", Char);
1437 table.intern("f32", Float(FloatTy::F32));
1438 table.intern("f64", Float(FloatTy::F64));
1439 table.intern("isize", Int(IntTy::Isize));
1440 table.intern("i8", Int(IntTy::I8));
1441 table.intern("i16", Int(IntTy::I16));
1442 table.intern("i32", Int(IntTy::I32));
1443 table.intern("i64", Int(IntTy::I64));
1444 table.intern("i128", Int(IntTy::I128));
1445 table.intern("str", Str);
1446 table.intern("usize", Uint(UintTy::Usize));
1447 table.intern("u8", Uint(UintTy::U8));
1448 table.intern("u16", Uint(UintTy::U16));
1449 table.intern("u32", Uint(UintTy::U32));
1450 table.intern("u64", Uint(UintTy::U64));
1451 table.intern("u128", Uint(UintTy::U128));
1455 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1456 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1460 #[derive(Default, Clone)]
1461 pub struct ExternPreludeEntry<'a> {
1462 extern_crate_item: Option<&'a NameBinding<'a>>,
1463 pub introduced_by_item: bool,
1466 /// The main resolver class.
1468 /// This is the visitor that walks the whole crate.
1469 pub struct Resolver<'a, 'b: 'a> {
1470 session: &'a Session,
1473 pub definitions: Definitions,
1475 graph_root: Module<'a>,
1477 prelude: Option<Module<'a>>,
1478 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1480 /// n.b. This is used only for better diagnostics, not name resolution itself.
1481 has_self: FxHashSet<DefId>,
1483 /// Names of fields of an item `DefId` accessible with dot syntax.
1484 /// Used for hints during error reporting.
1485 field_names: FxHashMap<DefId, Vec<Name>>,
1487 /// All imports known to succeed or fail.
1488 determined_imports: Vec<&'a ImportDirective<'a>>,
1490 /// All non-determined imports.
1491 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1493 /// The module that represents the current item scope.
1494 current_module: Module<'a>,
1496 /// The current set of local scopes for types and values.
1497 /// FIXME #4948: Reuse ribs to avoid allocation.
1498 ribs: PerNS<Vec<Rib<'a>>>,
1500 /// The current set of local scopes, for labels.
1501 label_ribs: Vec<Rib<'a>>,
1503 /// The trait that the current context can refer to.
1504 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1506 /// The current self type if inside an impl (used for better errors).
1507 current_self_type: Option<Ty>,
1509 /// The current self item if inside an ADT (used for better errors).
1510 current_self_item: Option<NodeId>,
1512 /// FIXME: Refactor things so that this is passed through arguments and not resolver.
1513 last_import_segment: bool,
1515 /// The idents for the primitive types.
1516 primitive_type_table: PrimitiveTypeTable,
1519 import_map: ImportMap,
1520 pub freevars: FreevarMap,
1521 freevars_seen: NodeMap<NodeMap<usize>>,
1522 pub export_map: ExportMap,
1523 pub trait_map: TraitMap,
1525 /// A map from nodes to anonymous modules.
1526 /// Anonymous modules are pseudo-modules that are implicitly created around items
1527 /// contained within blocks.
1529 /// For example, if we have this:
1537 /// There will be an anonymous module created around `g` with the ID of the
1538 /// entry block for `f`.
1539 block_map: NodeMap<Module<'a>>,
1540 module_map: FxHashMap<DefId, Module<'a>>,
1541 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1542 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1544 pub make_glob_map: bool,
1545 /// Maps imports to the names of items actually imported (this actually maps
1546 /// all imports, but only glob imports are actually interesting).
1547 pub glob_map: GlobMap,
1549 used_imports: FxHashSet<(NodeId, Namespace)>,
1550 pub maybe_unused_trait_imports: NodeSet,
1551 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1553 /// A list of labels as of yet unused. Labels will be removed from this map when
1554 /// they are used (in a `break` or `continue` statement)
1555 pub unused_labels: FxHashMap<NodeId, Span>,
1557 /// privacy errors are delayed until the end in order to deduplicate them
1558 privacy_errors: Vec<PrivacyError<'a>>,
1559 /// ambiguity errors are delayed for deduplication
1560 ambiguity_errors: Vec<AmbiguityError<'a>>,
1561 /// `use` injections are delayed for better placement and deduplication
1562 use_injections: Vec<UseError<'a>>,
1563 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1564 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1566 arenas: &'a ResolverArenas<'a>,
1567 dummy_binding: &'a NameBinding<'a>,
1569 crate_loader: &'a mut CrateLoader<'b>,
1570 macro_names: FxHashSet<Ident>,
1571 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1572 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1573 pub all_macros: FxHashMap<Name, Def>,
1574 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1575 macro_defs: FxHashMap<Mark, DefId>,
1576 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1577 pub whitelisted_legacy_custom_derives: Vec<Name>,
1578 pub found_unresolved_macro: bool,
1580 /// List of crate local macros that we need to warn about as being unused.
1581 /// Right now this only includes macro_rules! macros, and macros 2.0.
1582 unused_macros: FxHashSet<DefId>,
1584 /// Maps the `Mark` of an expansion to its containing module or block.
1585 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1587 /// Avoid duplicated errors for "name already defined".
1588 name_already_seen: FxHashMap<Name, Span>,
1590 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1592 /// This table maps struct IDs into struct constructor IDs,
1593 /// it's not used during normal resolution, only for better error reporting.
1594 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1596 /// Only used for better errors on `fn(): fn()`
1597 current_type_ascription: Vec<Span>,
1599 injected_crate: Option<Module<'a>>,
1602 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1604 pub struct ResolverArenas<'a> {
1605 modules: arena::TypedArena<ModuleData<'a>>,
1606 local_modules: RefCell<Vec<Module<'a>>>,
1607 name_bindings: arena::TypedArena<NameBinding<'a>>,
1608 import_directives: arena::TypedArena<ImportDirective<'a>>,
1609 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1610 invocation_data: arena::TypedArena<InvocationData<'a>>,
1611 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1614 impl<'a> ResolverArenas<'a> {
1615 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1616 let module = self.modules.alloc(module);
1617 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1618 self.local_modules.borrow_mut().push(module);
1622 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1623 self.local_modules.borrow()
1625 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1626 self.name_bindings.alloc(name_binding)
1628 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1629 -> &'a ImportDirective {
1630 self.import_directives.alloc(import_directive)
1632 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1633 self.name_resolutions.alloc(Default::default())
1635 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1636 -> &'a InvocationData<'a> {
1637 self.invocation_data.alloc(expansion_data)
1639 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1640 self.legacy_bindings.alloc(binding)
1644 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1645 fn parent(self, id: DefId) -> Option<DefId> {
1647 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1648 _ => self.cstore.def_key(id).parent,
1649 }.map(|index| DefId { index, ..id })
1653 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1654 /// the resolver is no longer needed as all the relevant information is inline.
1655 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1656 fn resolve_hir_path(
1661 self.resolve_hir_path_cb(path, is_value,
1662 |resolver, span, error| resolve_error(resolver, span, error))
1665 fn resolve_str_path(
1668 crate_root: Option<&str>,
1669 components: &[&str],
1672 let segments = iter::once(keywords::CrateRoot.ident())
1674 crate_root.into_iter()
1675 .chain(components.iter().cloned())
1676 .map(Ident::from_str)
1677 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1680 let path = ast::Path {
1685 self.resolve_hir_path(&path, is_value)
1688 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1689 self.def_map.get(&id).cloned()
1692 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1693 self.import_map.get(&id).cloned().unwrap_or_default()
1696 fn definitions(&mut self) -> &mut Definitions {
1697 &mut self.definitions
1701 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1702 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1703 /// isn't something that can be returned because it can't be made to live that long,
1704 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1705 /// just that an error occurred.
1706 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1707 -> Result<hir::Path, ()> {
1709 let mut errored = false;
1711 let path = if path_str.starts_with("::") {
1714 segments: iter::once(keywords::CrateRoot.ident())
1716 path_str.split("::").skip(1).map(Ident::from_str)
1718 .map(|i| self.new_ast_path_segment(i))
1726 .map(Ident::from_str)
1727 .map(|i| self.new_ast_path_segment(i))
1731 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1732 if errored || path.def == Def::Err {
1739 /// resolve_hir_path, but takes a callback in case there was an error
1740 fn resolve_hir_path_cb<F>(
1746 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1748 let namespace = if is_value { ValueNS } else { TypeNS };
1749 let span = path.span;
1750 let segments = &path.segments;
1751 let path = Segment::from_path(&path);
1752 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1753 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1754 span, CrateLint::No) {
1755 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1756 module.def().unwrap(),
1757 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1758 path_res.base_def(),
1759 PathResult::NonModule(..) => {
1760 let msg = "type-relative paths are not supported in this context";
1761 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1764 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1765 PathResult::Failed(span, msg, _) => {
1766 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1771 let segments: Vec<_> = segments.iter().map(|seg| {
1772 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1773 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1779 segments: segments.into(),
1783 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1784 let mut seg = ast::PathSegment::from_ident(ident);
1785 seg.id = self.session.next_node_id();
1790 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1791 pub fn new(session: &'a Session,
1795 make_glob_map: MakeGlobMap,
1796 crate_loader: &'a mut CrateLoader<'crateloader>,
1797 arenas: &'a ResolverArenas<'a>)
1798 -> Resolver<'a, 'crateloader> {
1799 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1800 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1801 let graph_root = arenas.alloc_module(ModuleData {
1802 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1803 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1805 let mut module_map = FxHashMap::default();
1806 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1808 let mut definitions = Definitions::new();
1809 DefCollector::new(&mut definitions, Mark::root())
1810 .collect_root(crate_name, session.local_crate_disambiguator());
1812 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1813 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1816 if !attr::contains_name(&krate.attrs, "no_core") {
1817 extern_prelude.insert(Ident::from_str("core"), Default::default());
1818 if !attr::contains_name(&krate.attrs, "no_std") {
1819 extern_prelude.insert(Ident::from_str("std"), Default::default());
1820 if session.rust_2018() {
1821 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1826 let mut invocations = FxHashMap::default();
1827 invocations.insert(Mark::root(),
1828 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1830 let mut macro_defs = FxHashMap::default();
1831 macro_defs.insert(Mark::root(), root_def_id);
1840 // The outermost module has def ID 0; this is not reflected in the
1846 has_self: FxHashSet::default(),
1847 field_names: FxHashMap::default(),
1849 determined_imports: Vec::new(),
1850 indeterminate_imports: Vec::new(),
1852 current_module: graph_root,
1854 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1855 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1856 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1858 label_ribs: Vec::new(),
1860 current_trait_ref: None,
1861 current_self_type: None,
1862 current_self_item: None,
1863 last_import_segment: false,
1865 primitive_type_table: PrimitiveTypeTable::new(),
1867 def_map: Default::default(),
1868 import_map: Default::default(),
1869 freevars: Default::default(),
1870 freevars_seen: Default::default(),
1871 export_map: FxHashMap::default(),
1872 trait_map: Default::default(),
1874 block_map: Default::default(),
1875 extern_module_map: FxHashMap::default(),
1876 binding_parent_modules: FxHashMap::default(),
1878 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1879 glob_map: Default::default(),
1881 used_imports: FxHashSet::default(),
1882 maybe_unused_trait_imports: Default::default(),
1883 maybe_unused_extern_crates: Vec::new(),
1885 unused_labels: FxHashMap::default(),
1887 privacy_errors: Vec::new(),
1888 ambiguity_errors: Vec::new(),
1889 use_injections: Vec::new(),
1890 macro_expanded_macro_export_errors: BTreeSet::new(),
1893 dummy_binding: arenas.alloc_name_binding(NameBinding {
1894 kind: NameBindingKind::Def(Def::Err, false),
1895 expansion: Mark::root(),
1897 vis: ty::Visibility::Public,
1901 macro_names: FxHashSet::default(),
1902 builtin_macros: FxHashMap::default(),
1903 macro_use_prelude: FxHashMap::default(),
1904 all_macros: FxHashMap::default(),
1905 macro_map: FxHashMap::default(),
1908 local_macro_def_scopes: FxHashMap::default(),
1909 name_already_seen: FxHashMap::default(),
1910 whitelisted_legacy_custom_derives: Vec::new(),
1911 potentially_unused_imports: Vec::new(),
1912 struct_constructors: Default::default(),
1913 found_unresolved_macro: false,
1914 unused_macros: FxHashSet::default(),
1915 current_type_ascription: Vec::new(),
1916 injected_crate: None,
1920 pub fn arenas() -> ResolverArenas<'a> {
1924 /// Runs the function on each namespace.
1925 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1931 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1933 match self.macro_defs.get(&ctxt.outer()) {
1934 Some(&def_id) => return def_id,
1935 None => ctxt.remove_mark(),
1940 /// Entry point to crate resolution.
1941 pub fn resolve_crate(&mut self, krate: &Crate) {
1942 ImportResolver { resolver: self }.finalize_imports();
1943 self.current_module = self.graph_root;
1944 self.finalize_current_module_macro_resolutions();
1946 visit::walk_crate(self, krate);
1948 check_unused::check_crate(self, krate);
1949 self.report_errors(krate);
1950 self.crate_loader.postprocess(krate);
1957 normal_ancestor_id: DefId,
1961 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1962 self.arenas.alloc_module(module)
1965 fn record_use(&mut self, ident: Ident, ns: Namespace,
1966 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1967 match used_binding.kind {
1968 NameBindingKind::Import { directive, binding, ref used } if !used.get() => {
1969 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1970 // but not introduce it, as used if they are accessed from lexical scope.
1971 if is_lexical_scope {
1972 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1973 if let Some(crate_item) = entry.extern_crate_item {
1974 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1981 directive.used.set(true);
1982 self.used_imports.insert((directive.id, ns));
1983 self.add_to_glob_map(directive.id, ident);
1984 self.record_use(ident, ns, binding, false);
1986 NameBindingKind::Ambiguity { kind, b1, b2 } => {
1987 self.ambiguity_errors.push(AmbiguityError {
1988 kind, ident, b1, b2,
1989 misc1: AmbiguityErrorMisc::None,
1990 misc2: AmbiguityErrorMisc::None,
1997 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1998 if self.make_glob_map {
1999 self.glob_map.entry(id).or_default().insert(ident.name);
2003 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2004 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2005 /// `ident` in the first scope that defines it (or None if no scopes define it).
2007 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2008 /// the items are defined in the block. For example,
2011 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2014 /// g(); // This resolves to the local variable `g` since it shadows the item.
2018 /// Invariant: This must only be called during main resolution, not during
2019 /// import resolution.
2020 fn resolve_ident_in_lexical_scope(&mut self,
2023 record_used_id: Option<NodeId>,
2025 -> Option<LexicalScopeBinding<'a>> {
2026 let record_used = record_used_id.is_some();
2027 assert!(ns == TypeNS || ns == ValueNS);
2029 ident.span = if ident.name == keywords::SelfType.name() {
2030 // FIXME(jseyfried) improve `Self` hygiene
2031 ident.span.with_ctxt(SyntaxContext::empty())
2036 ident = ident.modern_and_legacy();
2039 // Walk backwards up the ribs in scope.
2040 let mut module = self.graph_root;
2041 for i in (0 .. self.ribs[ns].len()).rev() {
2042 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2043 // The ident resolves to a type parameter or local variable.
2044 return Some(LexicalScopeBinding::Def(
2045 self.adjust_local_def(ns, i, def, record_used, path_span)
2049 module = match self.ribs[ns][i].kind {
2050 ModuleRibKind(module) => module,
2051 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2052 // If an invocation of this macro created `ident`, give up on `ident`
2053 // and switch to `ident`'s source from the macro definition.
2054 ident.span.remove_mark();
2060 let item = self.resolve_ident_in_module_unadjusted(
2061 ModuleOrUniformRoot::Module(module),
2067 if let Ok(binding) = item {
2068 // The ident resolves to an item.
2069 return Some(LexicalScopeBinding::Item(binding));
2073 ModuleKind::Block(..) => {}, // We can see through blocks
2078 ident.span = ident.span.modern();
2079 let mut poisoned = None;
2081 let opt_module = if let Some(node_id) = record_used_id {
2082 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2083 node_id, &mut poisoned)
2085 self.hygienic_lexical_parent(module, &mut ident.span)
2087 module = unwrap_or!(opt_module, break);
2088 let orig_current_module = self.current_module;
2089 self.current_module = module; // Lexical resolutions can never be a privacy error.
2090 let result = self.resolve_ident_in_module_unadjusted(
2091 ModuleOrUniformRoot::Module(module),
2097 self.current_module = orig_current_module;
2101 if let Some(node_id) = poisoned {
2102 self.session.buffer_lint_with_diagnostic(
2103 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2104 node_id, ident.span,
2105 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2106 lint::builtin::BuiltinLintDiagnostics::
2107 ProcMacroDeriveResolutionFallback(ident.span),
2110 return Some(LexicalScopeBinding::Item(binding))
2112 Err(Determined) => continue,
2113 Err(Undetermined) =>
2114 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2118 if !module.no_implicit_prelude {
2120 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2121 return Some(LexicalScopeBinding::Item(binding));
2124 if ns == TypeNS && is_known_tool(ident.name) {
2125 let binding = (Def::ToolMod, ty::Visibility::Public,
2126 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2127 return Some(LexicalScopeBinding::Item(binding));
2129 if let Some(prelude) = self.prelude {
2130 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2131 ModuleOrUniformRoot::Module(prelude),
2137 return Some(LexicalScopeBinding::Item(binding));
2145 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2146 -> Option<Module<'a>> {
2147 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2148 return Some(self.macro_def_scope(span.remove_mark()));
2151 if let ModuleKind::Block(..) = module.kind {
2152 return Some(module.parent.unwrap());
2158 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2159 span: &mut Span, node_id: NodeId,
2160 poisoned: &mut Option<NodeId>)
2161 -> Option<Module<'a>> {
2162 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2166 // We need to support the next case under a deprecation warning
2169 // ---- begin: this comes from a proc macro derive
2170 // mod implementation_details {
2171 // // Note that `MyStruct` is not in scope here.
2172 // impl SomeTrait for MyStruct { ... }
2176 // So we have to fall back to the module's parent during lexical resolution in this case.
2177 if let Some(parent) = module.parent {
2178 // Inner module is inside the macro, parent module is outside of the macro.
2179 if module.expansion != parent.expansion &&
2180 module.expansion.is_descendant_of(parent.expansion) {
2181 // The macro is a proc macro derive
2182 if module.expansion.looks_like_proc_macro_derive() {
2183 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2184 *poisoned = Some(node_id);
2185 return module.parent;
2194 fn resolve_ident_in_module(
2196 module: ModuleOrUniformRoot<'a>,
2199 parent_scope: Option<&ParentScope<'a>>,
2202 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2203 self.resolve_ident_in_module_ext(
2204 module, ident, ns, parent_scope, record_used, path_span
2205 ).map_err(|(determinacy, _)| determinacy)
2208 fn resolve_ident_in_module_ext(
2210 module: ModuleOrUniformRoot<'a>,
2213 parent_scope: Option<&ParentScope<'a>>,
2216 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2217 let orig_current_module = self.current_module;
2219 ModuleOrUniformRoot::Module(module) => {
2220 ident.span = ident.span.modern();
2221 if let Some(def) = ident.span.adjust(module.expansion) {
2222 self.current_module = self.macro_def_scope(def);
2225 ModuleOrUniformRoot::ExternPrelude => {
2226 ident.span = ident.span.modern();
2227 ident.span.adjust(Mark::root());
2229 ModuleOrUniformRoot::CurrentScope => {
2233 let result = self.resolve_ident_in_module_unadjusted_ext(
2234 module, ident, ns, parent_scope, false, record_used, path_span,
2236 self.current_module = orig_current_module;
2240 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2241 let mut ctxt = ident.span.ctxt();
2242 let mark = if ident.name == keywords::DollarCrate.name() {
2243 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2244 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2245 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2246 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2247 // definitions actually produced by `macro` and `macro` definitions produced by
2248 // `macro_rules!`, but at least such configurations are not stable yet.
2249 ctxt = ctxt.modern_and_legacy();
2250 let mut iter = ctxt.marks().into_iter().rev().peekable();
2251 let mut result = None;
2252 // Find the last modern mark from the end if it exists.
2253 while let Some(&(mark, transparency)) = iter.peek() {
2254 if transparency == Transparency::Opaque {
2255 result = Some(mark);
2261 // Then find the last legacy mark from the end if it exists.
2262 for (mark, transparency) in iter {
2263 if transparency == Transparency::SemiTransparent {
2264 result = Some(mark);
2271 ctxt = ctxt.modern();
2272 ctxt.adjust(Mark::root())
2274 let module = match mark {
2275 Some(def) => self.macro_def_scope(def),
2276 None => return self.graph_root,
2278 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2281 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2282 let mut module = self.get_module(module.normal_ancestor_id);
2283 while module.span.ctxt().modern() != *ctxt {
2284 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2285 module = self.get_module(parent.normal_ancestor_id);
2292 // We maintain a list of value ribs and type ribs.
2294 // Simultaneously, we keep track of the current position in the module
2295 // graph in the `current_module` pointer. When we go to resolve a name in
2296 // the value or type namespaces, we first look through all the ribs and
2297 // then query the module graph. When we resolve a name in the module
2298 // namespace, we can skip all the ribs (since nested modules are not
2299 // allowed within blocks in Rust) and jump straight to the current module
2302 // Named implementations are handled separately. When we find a method
2303 // call, we consult the module node to find all of the implementations in
2304 // scope. This information is lazily cached in the module node. We then
2305 // generate a fake "implementation scope" containing all the
2306 // implementations thus found, for compatibility with old resolve pass.
2308 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2309 where F: FnOnce(&mut Resolver) -> T
2311 let id = self.definitions.local_def_id(id);
2312 let module = self.module_map.get(&id).cloned(); // clones a reference
2313 if let Some(module) = module {
2314 // Move down in the graph.
2315 let orig_module = replace(&mut self.current_module, module);
2316 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2317 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2319 self.finalize_current_module_macro_resolutions();
2322 self.current_module = orig_module;
2323 self.ribs[ValueNS].pop();
2324 self.ribs[TypeNS].pop();
2331 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2332 /// is returned by the given predicate function
2334 /// Stops after meeting a closure.
2335 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2336 where P: Fn(&Rib, Ident) -> Option<R>
2338 for rib in self.label_ribs.iter().rev() {
2341 // If an invocation of this macro created `ident`, give up on `ident`
2342 // and switch to `ident`'s source from the macro definition.
2343 MacroDefinition(def) => {
2344 if def == self.macro_def(ident.span.ctxt()) {
2345 ident.span.remove_mark();
2349 // Do not resolve labels across function boundary
2353 let r = pred(rib, ident);
2361 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2362 self.with_current_self_item(item, |this| {
2363 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2364 let item_def_id = this.definitions.local_def_id(item.id);
2365 if this.session.features_untracked().self_in_typedefs {
2366 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2367 visit::walk_item(this, item);
2370 visit::walk_item(this, item);
2376 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2377 let segments = &use_tree.prefix.segments;
2378 if !segments.is_empty() {
2379 let ident = segments[0].ident;
2380 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2384 let nss = match use_tree.kind {
2385 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2389 if let Some(LexicalScopeBinding::Def(..)) =
2390 self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2391 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2392 self.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2395 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2396 for (use_tree, _) in use_trees {
2397 self.future_proof_import(use_tree);
2402 fn resolve_item(&mut self, item: &Item) {
2403 let name = item.ident.name;
2404 debug!("(resolving item) resolving {}", name);
2407 ItemKind::Ty(_, ref generics) |
2408 ItemKind::Fn(_, _, ref generics, _) |
2409 ItemKind::Existential(_, ref generics) => {
2410 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2411 |this| visit::walk_item(this, item));
2414 ItemKind::Enum(_, ref generics) |
2415 ItemKind::Struct(_, ref generics) |
2416 ItemKind::Union(_, ref generics) => {
2417 self.resolve_adt(item, generics);
2420 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2421 self.resolve_implementation(generics,
2427 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2428 // Create a new rib for the trait-wide type parameters.
2429 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2430 let local_def_id = this.definitions.local_def_id(item.id);
2431 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2432 this.visit_generics(generics);
2433 walk_list!(this, visit_param_bound, bounds);
2435 for trait_item in trait_items {
2436 let type_parameters = HasTypeParameters(&trait_item.generics,
2437 TraitOrImplItemRibKind);
2438 this.with_type_parameter_rib(type_parameters, |this| {
2439 match trait_item.node {
2440 TraitItemKind::Const(ref ty, ref default) => {
2443 // Only impose the restrictions of
2444 // ConstRibKind for an actual constant
2445 // expression in a provided default.
2446 if let Some(ref expr) = *default{
2447 this.with_constant_rib(|this| {
2448 this.visit_expr(expr);
2452 TraitItemKind::Method(_, _) => {
2453 visit::walk_trait_item(this, trait_item)
2455 TraitItemKind::Type(..) => {
2456 visit::walk_trait_item(this, trait_item)
2458 TraitItemKind::Macro(_) => {
2459 panic!("unexpanded macro in resolve!")
2468 ItemKind::TraitAlias(ref generics, ref bounds) => {
2469 // Create a new rib for the trait-wide type parameters.
2470 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2471 let local_def_id = this.definitions.local_def_id(item.id);
2472 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2473 this.visit_generics(generics);
2474 walk_list!(this, visit_param_bound, bounds);
2479 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2480 self.with_scope(item.id, |this| {
2481 visit::walk_item(this, item);
2485 ItemKind::Static(ref ty, _, ref expr) |
2486 ItemKind::Const(ref ty, ref expr) => {
2487 self.with_item_rib(|this| {
2489 this.with_constant_rib(|this| {
2490 this.visit_expr(expr);
2495 ItemKind::Use(ref use_tree) => {
2496 self.future_proof_import(use_tree);
2499 ItemKind::ExternCrate(..) |
2500 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2501 // do nothing, these are just around to be encoded
2504 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2508 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2509 where F: FnOnce(&mut Resolver)
2511 match type_parameters {
2512 HasTypeParameters(generics, rib_kind) => {
2513 let mut function_type_rib = Rib::new(rib_kind);
2514 let mut seen_bindings = FxHashMap::default();
2515 for param in &generics.params {
2517 GenericParamKind::Lifetime { .. } => {}
2518 GenericParamKind::Type { .. } => {
2519 let ident = param.ident.modern();
2520 debug!("with_type_parameter_rib: {}", param.id);
2522 if seen_bindings.contains_key(&ident) {
2523 let span = seen_bindings.get(&ident).unwrap();
2524 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2528 resolve_error(self, param.ident.span, err);
2530 seen_bindings.entry(ident).or_insert(param.ident.span);
2532 // Plain insert (no renaming).
2533 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2534 function_type_rib.bindings.insert(ident, def);
2535 self.record_def(param.id, PathResolution::new(def));
2539 self.ribs[TypeNS].push(function_type_rib);
2542 NoTypeParameters => {
2549 if let HasTypeParameters(..) = type_parameters {
2550 self.ribs[TypeNS].pop();
2554 fn with_label_rib<F>(&mut self, f: F)
2555 where F: FnOnce(&mut Resolver)
2557 self.label_ribs.push(Rib::new(NormalRibKind));
2559 self.label_ribs.pop();
2562 fn with_item_rib<F>(&mut self, f: F)
2563 where F: FnOnce(&mut Resolver)
2565 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2566 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2568 self.ribs[TypeNS].pop();
2569 self.ribs[ValueNS].pop();
2572 fn with_constant_rib<F>(&mut self, f: F)
2573 where F: FnOnce(&mut Resolver)
2575 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2576 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2578 self.label_ribs.pop();
2579 self.ribs[ValueNS].pop();
2582 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2583 where F: FnOnce(&mut Resolver) -> T
2585 // Handle nested impls (inside fn bodies)
2586 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2587 let result = f(self);
2588 self.current_self_type = previous_value;
2592 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2593 where F: FnOnce(&mut Resolver) -> T
2595 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2596 let result = f(self);
2597 self.current_self_item = previous_value;
2601 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2602 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2603 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2605 let mut new_val = None;
2606 let mut new_id = None;
2607 if let Some(trait_ref) = opt_trait_ref {
2608 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2609 let def = self.smart_resolve_path_fragment(
2613 trait_ref.path.span,
2614 PathSource::Trait(AliasPossibility::No),
2615 CrateLint::SimplePath(trait_ref.ref_id),
2617 if def != Def::Err {
2618 new_id = Some(def.def_id());
2619 let span = trait_ref.path.span;
2620 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2621 self.resolve_path_without_parent_scope(
2626 CrateLint::SimplePath(trait_ref.ref_id),
2629 new_val = Some((module, trait_ref.clone()));
2633 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2634 let result = f(self, new_id);
2635 self.current_trait_ref = original_trait_ref;
2639 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2640 where F: FnOnce(&mut Resolver)
2642 let mut self_type_rib = Rib::new(NormalRibKind);
2644 // plain insert (no renaming, types are not currently hygienic....)
2645 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2646 self.ribs[TypeNS].push(self_type_rib);
2648 self.ribs[TypeNS].pop();
2651 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2652 where F: FnOnce(&mut Resolver)
2654 let self_def = Def::SelfCtor(impl_id);
2655 let mut self_type_rib = Rib::new(NormalRibKind);
2656 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2657 self.ribs[ValueNS].push(self_type_rib);
2659 self.ribs[ValueNS].pop();
2662 fn resolve_implementation(&mut self,
2663 generics: &Generics,
2664 opt_trait_reference: &Option<TraitRef>,
2667 impl_items: &[ImplItem]) {
2668 // If applicable, create a rib for the type parameters.
2669 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2670 // Dummy self type for better errors if `Self` is used in the trait path.
2671 this.with_self_rib(Def::SelfTy(None, None), |this| {
2672 // Resolve the trait reference, if necessary.
2673 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2674 let item_def_id = this.definitions.local_def_id(item_id);
2675 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2676 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2677 // Resolve type arguments in the trait path.
2678 visit::walk_trait_ref(this, trait_ref);
2680 // Resolve the self type.
2681 this.visit_ty(self_type);
2682 // Resolve the type parameters.
2683 this.visit_generics(generics);
2684 // Resolve the items within the impl.
2685 this.with_current_self_type(self_type, |this| {
2686 this.with_self_struct_ctor_rib(item_def_id, |this| {
2687 for impl_item in impl_items {
2688 this.resolve_visibility(&impl_item.vis);
2690 // We also need a new scope for the impl item type parameters.
2691 let type_parameters = HasTypeParameters(&impl_item.generics,
2692 TraitOrImplItemRibKind);
2693 this.with_type_parameter_rib(type_parameters, |this| {
2694 use self::ResolutionError::*;
2695 match impl_item.node {
2696 ImplItemKind::Const(..) => {
2697 // If this is a trait impl, ensure the const
2699 this.check_trait_item(impl_item.ident,
2702 |n, s| ConstNotMemberOfTrait(n, s));
2703 this.with_constant_rib(|this|
2704 visit::walk_impl_item(this, impl_item)
2707 ImplItemKind::Method(..) => {
2708 // If this is a trait impl, ensure the method
2710 this.check_trait_item(impl_item.ident,
2713 |n, s| MethodNotMemberOfTrait(n, s));
2715 visit::walk_impl_item(this, impl_item);
2717 ImplItemKind::Type(ref ty) => {
2718 // If this is a trait impl, ensure the type
2720 this.check_trait_item(impl_item.ident,
2723 |n, s| TypeNotMemberOfTrait(n, s));
2727 ImplItemKind::Existential(ref bounds) => {
2728 // If this is a trait impl, ensure the type
2730 this.check_trait_item(impl_item.ident,
2733 |n, s| TypeNotMemberOfTrait(n, s));
2735 for bound in bounds {
2736 this.visit_param_bound(bound);
2739 ImplItemKind::Macro(_) =>
2740 panic!("unexpanded macro in resolve!"),
2752 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2753 where F: FnOnce(Name, &str) -> ResolutionError
2755 // If there is a TraitRef in scope for an impl, then the method must be in the
2757 if let Some((module, _)) = self.current_trait_ref {
2758 if self.resolve_ident_in_module(
2759 ModuleOrUniformRoot::Module(module),
2766 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2767 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2772 fn resolve_local(&mut self, local: &Local) {
2773 // Resolve the type.
2774 walk_list!(self, visit_ty, &local.ty);
2776 // Resolve the initializer.
2777 walk_list!(self, visit_expr, &local.init);
2779 // Resolve the pattern.
2780 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2783 // build a map from pattern identifiers to binding-info's.
2784 // this is done hygienically. This could arise for a macro
2785 // that expands into an or-pattern where one 'x' was from the
2786 // user and one 'x' came from the macro.
2787 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2788 let mut binding_map = FxHashMap::default();
2790 pat.walk(&mut |pat| {
2791 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2792 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2793 Some(Def::Local(..)) => true,
2796 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2797 binding_map.insert(ident, binding_info);
2806 // check that all of the arms in an or-pattern have exactly the
2807 // same set of bindings, with the same binding modes for each.
2808 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2809 if pats.is_empty() {
2813 let mut missing_vars = FxHashMap::default();
2814 let mut inconsistent_vars = FxHashMap::default();
2815 for (i, p) in pats.iter().enumerate() {
2816 let map_i = self.binding_mode_map(&p);
2818 for (j, q) in pats.iter().enumerate() {
2823 let map_j = self.binding_mode_map(&q);
2824 for (&key, &binding_i) in &map_i {
2825 if map_j.is_empty() { // Account for missing bindings when
2826 let binding_error = missing_vars // map_j has none.
2828 .or_insert(BindingError {
2830 origin: BTreeSet::new(),
2831 target: BTreeSet::new(),
2833 binding_error.origin.insert(binding_i.span);
2834 binding_error.target.insert(q.span);
2836 for (&key_j, &binding_j) in &map_j {
2837 match map_i.get(&key_j) {
2838 None => { // missing binding
2839 let binding_error = missing_vars
2841 .or_insert(BindingError {
2843 origin: BTreeSet::new(),
2844 target: BTreeSet::new(),
2846 binding_error.origin.insert(binding_j.span);
2847 binding_error.target.insert(p.span);
2849 Some(binding_i) => { // check consistent binding
2850 if binding_i.binding_mode != binding_j.binding_mode {
2853 .or_insert((binding_j.span, binding_i.span));
2861 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2862 missing_vars.sort();
2863 for (_, v) in missing_vars {
2865 *v.origin.iter().next().unwrap(),
2866 ResolutionError::VariableNotBoundInPattern(v));
2868 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2869 inconsistent_vars.sort();
2870 for (name, v) in inconsistent_vars {
2871 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2875 fn resolve_arm(&mut self, arm: &Arm) {
2876 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2878 let mut bindings_list = FxHashMap::default();
2879 for pattern in &arm.pats {
2880 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2883 // This has to happen *after* we determine which pat_idents are variants
2884 self.check_consistent_bindings(&arm.pats);
2886 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2887 self.visit_expr(expr)
2889 self.visit_expr(&arm.body);
2891 self.ribs[ValueNS].pop();
2894 fn resolve_block(&mut self, block: &Block) {
2895 debug!("(resolving block) entering block");
2896 // Move down in the graph, if there's an anonymous module rooted here.
2897 let orig_module = self.current_module;
2898 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2900 let mut num_macro_definition_ribs = 0;
2901 if let Some(anonymous_module) = anonymous_module {
2902 debug!("(resolving block) found anonymous module, moving down");
2903 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2904 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2905 self.current_module = anonymous_module;
2906 self.finalize_current_module_macro_resolutions();
2908 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2911 // Descend into the block.
2912 for stmt in &block.stmts {
2913 if let ast::StmtKind::Item(ref item) = stmt.node {
2914 if let ast::ItemKind::MacroDef(..) = item.node {
2915 num_macro_definition_ribs += 1;
2916 let def = self.definitions.local_def_id(item.id);
2917 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2918 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2922 self.visit_stmt(stmt);
2926 self.current_module = orig_module;
2927 for _ in 0 .. num_macro_definition_ribs {
2928 self.ribs[ValueNS].pop();
2929 self.label_ribs.pop();
2931 self.ribs[ValueNS].pop();
2932 if anonymous_module.is_some() {
2933 self.ribs[TypeNS].pop();
2935 debug!("(resolving block) leaving block");
2938 fn fresh_binding(&mut self,
2941 outer_pat_id: NodeId,
2942 pat_src: PatternSource,
2943 bindings: &mut FxHashMap<Ident, NodeId>)
2945 // Add the binding to the local ribs, if it
2946 // doesn't already exist in the bindings map. (We
2947 // must not add it if it's in the bindings map
2948 // because that breaks the assumptions later
2949 // passes make about or-patterns.)
2950 let ident = ident.modern_and_legacy();
2951 let mut def = Def::Local(pat_id);
2952 match bindings.get(&ident).cloned() {
2953 Some(id) if id == outer_pat_id => {
2954 // `Variant(a, a)`, error
2958 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2962 Some(..) if pat_src == PatternSource::FnParam => {
2963 // `fn f(a: u8, a: u8)`, error
2967 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2971 Some(..) if pat_src == PatternSource::Match ||
2972 pat_src == PatternSource::IfLet ||
2973 pat_src == PatternSource::WhileLet => {
2974 // `Variant1(a) | Variant2(a)`, ok
2975 // Reuse definition from the first `a`.
2976 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2979 span_bug!(ident.span, "two bindings with the same name from \
2980 unexpected pattern source {:?}", pat_src);
2983 // A completely fresh binding, add to the lists if it's valid.
2984 if ident.name != keywords::Invalid.name() {
2985 bindings.insert(ident, outer_pat_id);
2986 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2991 PathResolution::new(def)
2994 fn resolve_pattern(&mut self,
2996 pat_src: PatternSource,
2997 // Maps idents to the node ID for the
2998 // outermost pattern that binds them.
2999 bindings: &mut FxHashMap<Ident, NodeId>) {
3000 // Visit all direct subpatterns of this pattern.
3001 let outer_pat_id = pat.id;
3002 pat.walk(&mut |pat| {
3004 PatKind::Ident(bmode, ident, ref opt_pat) => {
3005 // First try to resolve the identifier as some existing
3006 // entity, then fall back to a fresh binding.
3007 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3009 .and_then(LexicalScopeBinding::item);
3010 let resolution = binding.map(NameBinding::def).and_then(|def| {
3011 let is_syntactic_ambiguity = opt_pat.is_none() &&
3012 bmode == BindingMode::ByValue(Mutability::Immutable);
3014 Def::StructCtor(_, CtorKind::Const) |
3015 Def::VariantCtor(_, CtorKind::Const) |
3016 Def::Const(..) if is_syntactic_ambiguity => {
3017 // Disambiguate in favor of a unit struct/variant
3018 // or constant pattern.
3019 self.record_use(ident, ValueNS, binding.unwrap(), false);
3020 Some(PathResolution::new(def))
3022 Def::StructCtor(..) | Def::VariantCtor(..) |
3023 Def::Const(..) | Def::Static(..) => {
3024 // This is unambiguously a fresh binding, either syntactically
3025 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3026 // to something unusable as a pattern (e.g. constructor function),
3027 // but we still conservatively report an error, see
3028 // issues/33118#issuecomment-233962221 for one reason why.
3032 ResolutionError::BindingShadowsSomethingUnacceptable(
3033 pat_src.descr(), ident.name, binding.unwrap())
3037 Def::Fn(..) | Def::Err => {
3038 // These entities are explicitly allowed
3039 // to be shadowed by fresh bindings.
3043 span_bug!(ident.span, "unexpected definition for an \
3044 identifier in pattern: {:?}", def);
3047 }).unwrap_or_else(|| {
3048 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3051 self.record_def(pat.id, resolution);
3054 PatKind::TupleStruct(ref path, ..) => {
3055 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3058 PatKind::Path(ref qself, ref path) => {
3059 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3062 PatKind::Struct(ref path, ..) => {
3063 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3071 visit::walk_pat(self, pat);
3074 // High-level and context dependent path resolution routine.
3075 // Resolves the path and records the resolution into definition map.
3076 // If resolution fails tries several techniques to find likely
3077 // resolution candidates, suggest imports or other help, and report
3078 // errors in user friendly way.
3079 fn smart_resolve_path(&mut self,
3081 qself: Option<&QSelf>,
3085 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3088 /// A variant of `smart_resolve_path` where you also specify extra
3089 /// information about where the path came from; this extra info is
3090 /// sometimes needed for the lint that recommends rewriting
3091 /// absolute paths to `crate`, so that it knows how to frame the
3092 /// suggestion. If you are just resolving a path like `foo::bar`
3093 /// that appears...somewhere, though, then you just want
3094 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3095 /// already provides.
3096 fn smart_resolve_path_with_crate_lint(
3099 qself: Option<&QSelf>,
3102 crate_lint: CrateLint
3103 ) -> PathResolution {
3104 self.smart_resolve_path_fragment(
3107 &Segment::from_path(path),
3114 fn smart_resolve_path_fragment(&mut self,
3116 qself: Option<&QSelf>,
3120 crate_lint: CrateLint)
3122 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3123 let ns = source.namespace();
3124 let is_expected = &|def| source.is_expected(def);
3125 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3127 // Base error is amended with one short label and possibly some longer helps/notes.
3128 let report_errors = |this: &mut Self, def: Option<Def>| {
3129 // Make the base error.
3130 let expected = source.descr_expected();
3131 let path_str = Segment::names_to_string(path);
3132 let item_str = path.last().unwrap().ident;
3133 let code = source.error_code(def.is_some());
3134 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3135 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3136 format!("not a {}", expected),
3139 let item_span = path.last().unwrap().ident.span;
3140 let (mod_prefix, mod_str) = if path.len() == 1 {
3141 (String::new(), "this scope".to_string())
3142 } else if path.len() == 2 && path[0].ident.name == keywords::CrateRoot.name() {
3143 (String::new(), "the crate root".to_string())
3145 let mod_path = &path[..path.len() - 1];
3146 let mod_prefix = match this.resolve_path_without_parent_scope(
3147 mod_path, Some(TypeNS), false, span, CrateLint::No
3149 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3152 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3153 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3155 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3156 format!("not found in {}", mod_str),
3159 let code = DiagnosticId::Error(code.into());
3160 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3162 // Emit help message for fake-self from other languages like `this`(javascript)
3163 if ["this", "my"].contains(&&*item_str.as_str())
3164 && this.self_value_is_available(path[0].ident.span, span) {
3165 err.span_suggestion_with_applicability(
3169 Applicability::MaybeIncorrect,
3173 // Emit special messages for unresolved `Self` and `self`.
3174 if is_self_type(path, ns) {
3175 __diagnostic_used!(E0411);
3176 err.code(DiagnosticId::Error("E0411".into()));
3177 let available_in = if this.session.features_untracked().self_in_typedefs {
3178 "impls, traits, and type definitions"
3182 err.span_label(span, format!("`Self` is only available in {}", available_in));
3183 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3184 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3187 return (err, Vec::new());
3189 if is_self_value(path, ns) {
3190 __diagnostic_used!(E0424);
3191 err.code(DiagnosticId::Error("E0424".into()));
3192 err.span_label(span, format!("`self` value is a keyword \
3194 methods with `self` parameter"));
3195 return (err, Vec::new());
3198 // Try to lookup the name in more relaxed fashion for better error reporting.
3199 let ident = path.last().unwrap().ident;
3200 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3201 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3202 let enum_candidates =
3203 this.lookup_import_candidates(ident, ns, is_enum_variant);
3204 let mut enum_candidates = enum_candidates.iter()
3205 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3206 enum_candidates.sort();
3207 for (sp, variant_path, enum_path) in enum_candidates {
3209 let msg = format!("there is an enum variant `{}`, \
3215 err.span_suggestion_with_applicability(
3217 "you can try using the variant's enum",
3219 Applicability::MachineApplicable,
3224 if path.len() == 1 && this.self_type_is_available(span) {
3225 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3226 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3228 AssocSuggestion::Field => {
3229 err.span_suggestion_with_applicability(
3232 format!("self.{}", path_str),
3233 Applicability::MachineApplicable,
3235 if !self_is_available {
3236 err.span_label(span, format!("`self` value is a keyword \
3238 methods with `self` parameter"));
3241 AssocSuggestion::MethodWithSelf if self_is_available => {
3242 err.span_suggestion_with_applicability(
3245 format!("self.{}", path_str),
3246 Applicability::MachineApplicable,
3249 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3250 err.span_suggestion_with_applicability(
3253 format!("Self::{}", path_str),
3254 Applicability::MachineApplicable,
3258 return (err, candidates);
3262 let mut levenshtein_worked = false;
3265 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3266 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3267 levenshtein_worked = true;
3270 // Try context dependent help if relaxed lookup didn't work.
3271 if let Some(def) = def {
3272 match (def, source) {
3273 (Def::Macro(..), _) => {
3274 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3275 return (err, candidates);
3277 (Def::TyAlias(..), PathSource::Trait(_)) => {
3278 err.span_label(span, "type aliases cannot be used as traits");
3279 if nightly_options::is_nightly_build() {
3280 err.note("did you mean to use a trait alias?");
3282 return (err, candidates);
3284 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3285 ExprKind::Field(_, ident) => {
3286 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3288 return (err, candidates);
3290 ExprKind::MethodCall(ref segment, ..) => {
3291 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3292 path_str, segment.ident));
3293 return (err, candidates);
3297 (Def::Enum(..), PathSource::TupleStruct)
3298 | (Def::Enum(..), PathSource::Expr(..)) => {
3299 if let Some(variants) = this.collect_enum_variants(def) {
3300 err.note(&format!("did you mean to use one \
3301 of the following variants?\n{}",
3303 .map(|suggestion| path_names_to_string(suggestion))
3304 .map(|suggestion| format!("- `{}`", suggestion))
3305 .collect::<Vec<_>>()
3309 err.note("did you mean to use one of the enum's variants?");
3311 return (err, candidates);
3313 (Def::Struct(def_id), _) if ns == ValueNS => {
3314 if let Some((ctor_def, ctor_vis))
3315 = this.struct_constructors.get(&def_id).cloned() {
3316 let accessible_ctor = this.is_accessible(ctor_vis);
3317 if is_expected(ctor_def) && !accessible_ctor {
3318 err.span_label(span, format!("constructor is not visible \
3319 here due to private fields"));
3322 // HACK(estebank): find a better way to figure out that this was a
3323 // parser issue where a struct literal is being used on an expression
3324 // where a brace being opened means a block is being started. Look
3325 // ahead for the next text to see if `span` is followed by a `{`.
3326 let sm = this.session.source_map();
3329 sp = sm.next_point(sp);
3330 match sm.span_to_snippet(sp) {
3331 Ok(ref snippet) => {
3332 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3339 let followed_by_brace = match sm.span_to_snippet(sp) {
3340 Ok(ref snippet) if snippet == "{" => true,
3344 PathSource::Expr(Some(parent)) => {
3346 ExprKind::MethodCall(ref path_assignment, _) => {
3347 err.span_suggestion_with_applicability(
3348 sm.start_point(parent.span)
3349 .to(path_assignment.ident.span),
3350 "use `::` to access an associated function",
3353 path_assignment.ident),
3354 Applicability::MaybeIncorrect
3356 return (err, candidates);
3361 format!("did you mean `{} {{ /* fields */ }}`?",
3364 return (err, candidates);
3368 PathSource::Expr(None) if followed_by_brace == true => {
3371 format!("did you mean `({} {{ /* fields */ }})`?",
3374 return (err, candidates);
3379 format!("did you mean `{} {{ /* fields */ }}`?",
3382 return (err, candidates);
3386 return (err, candidates);
3388 (Def::Union(..), _) |
3389 (Def::Variant(..), _) |
3390 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3391 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3393 return (err, candidates);
3395 (Def::SelfTy(..), _) if ns == ValueNS => {
3396 err.span_label(span, fallback_label);
3397 err.note("can't use `Self` as a constructor, you must use the \
3398 implemented struct");
3399 return (err, candidates);
3401 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3402 err.note("can't use a type alias as a constructor");
3403 return (err, candidates);
3410 if !levenshtein_worked {
3411 err.span_label(base_span, fallback_label);
3412 this.type_ascription_suggestion(&mut err, base_span);
3416 let report_errors = |this: &mut Self, def: Option<Def>| {
3417 let (err, candidates) = report_errors(this, def);
3418 let def_id = this.current_module.normal_ancestor_id;
3419 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3420 let better = def.is_some();
3421 this.use_injections.push(UseError { err, candidates, node_id, better });
3422 err_path_resolution()
3425 let resolution = match self.resolve_qpath_anywhere(
3431 source.defer_to_typeck(),
3432 source.global_by_default(),
3435 Some(resolution) if resolution.unresolved_segments() == 0 => {
3436 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3439 // Add a temporary hack to smooth the transition to new struct ctor
3440 // visibility rules. See #38932 for more details.
3442 if let Def::Struct(def_id) = resolution.base_def() {
3443 if let Some((ctor_def, ctor_vis))
3444 = self.struct_constructors.get(&def_id).cloned() {
3445 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3446 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3447 self.session.buffer_lint(lint, id, span,
3448 "private struct constructors are not usable through \
3449 re-exports in outer modules",
3451 res = Some(PathResolution::new(ctor_def));
3456 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3459 Some(resolution) if source.defer_to_typeck() => {
3460 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3461 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3462 // it needs to be added to the trait map.
3464 let item_name = path.last().unwrap().ident;
3465 let traits = self.get_traits_containing_item(item_name, ns);
3466 self.trait_map.insert(id, traits);
3470 _ => report_errors(self, None)
3473 if let PathSource::TraitItem(..) = source {} else {
3474 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3475 self.record_def(id, resolution);
3480 fn type_ascription_suggestion(&self,
3481 err: &mut DiagnosticBuilder,
3483 debug!("type_ascription_suggetion {:?}", base_span);
3484 let cm = self.session.source_map();
3485 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3486 if let Some(sp) = self.current_type_ascription.last() {
3488 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3489 sp = cm.next_point(sp);
3490 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3491 debug!("snippet {:?}", snippet);
3492 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3493 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3494 debug!("{:?} {:?}", line_sp, line_base_sp);
3496 err.span_label(base_span,
3497 "expecting a type here because of type ascription");
3498 if line_sp != line_base_sp {
3499 err.span_suggestion_short_with_applicability(
3501 "did you mean to use `;` here instead?",
3503 Applicability::MaybeIncorrect,
3507 } else if !snippet.trim().is_empty() {
3508 debug!("tried to find type ascription `:` token, couldn't find it");
3518 fn self_type_is_available(&mut self, span: Span) -> bool {
3519 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3520 TypeNS, None, span);
3521 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3524 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3525 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3526 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3527 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3530 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3531 fn resolve_qpath_anywhere(&mut self,
3533 qself: Option<&QSelf>,
3535 primary_ns: Namespace,
3537 defer_to_typeck: bool,
3538 global_by_default: bool,
3539 crate_lint: CrateLint)
3540 -> Option<PathResolution> {
3541 let mut fin_res = None;
3542 // FIXME: can't resolve paths in macro namespace yet, macros are
3543 // processed by the little special hack below.
3544 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3545 if i == 0 || ns != primary_ns {
3546 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3547 // If defer_to_typeck, then resolution > no resolution,
3548 // otherwise full resolution > partial resolution > no resolution.
3549 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3551 res => if fin_res.is_none() { fin_res = res },
3555 if primary_ns != MacroNS &&
3556 (self.macro_names.contains(&path[0].ident.modern()) ||
3557 self.builtin_macros.get(&path[0].ident.name).cloned()
3558 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3559 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3560 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3561 // Return some dummy definition, it's enough for error reporting.
3563 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3569 /// Handles paths that may refer to associated items.
3570 fn resolve_qpath(&mut self,
3572 qself: Option<&QSelf>,
3576 global_by_default: bool,
3577 crate_lint: CrateLint)
3578 -> Option<PathResolution> {
3580 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3581 ns={:?}, span={:?}, global_by_default={:?})",
3590 if let Some(qself) = qself {
3591 if qself.position == 0 {
3592 // This is a case like `<T>::B`, where there is no
3593 // trait to resolve. In that case, we leave the `B`
3594 // segment to be resolved by type-check.
3595 return Some(PathResolution::with_unresolved_segments(
3596 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3600 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3602 // Currently, `path` names the full item (`A::B::C`, in
3603 // our example). so we extract the prefix of that that is
3604 // the trait (the slice upto and including
3605 // `qself.position`). And then we recursively resolve that,
3606 // but with `qself` set to `None`.
3608 // However, setting `qself` to none (but not changing the
3609 // span) loses the information about where this path
3610 // *actually* appears, so for the purposes of the crate
3611 // lint we pass along information that this is the trait
3612 // name from a fully qualified path, and this also
3613 // contains the full span (the `CrateLint::QPathTrait`).
3614 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3615 let res = self.smart_resolve_path_fragment(
3618 &path[..qself.position + 1],
3620 PathSource::TraitItem(ns),
3621 CrateLint::QPathTrait {
3623 qpath_span: qself.path_span,
3627 // The remaining segments (the `C` in our example) will
3628 // have to be resolved by type-check, since that requires doing
3629 // trait resolution.
3630 return Some(PathResolution::with_unresolved_segments(
3631 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3635 let result = match self.resolve_path_without_parent_scope(
3642 PathResult::NonModule(path_res) => path_res,
3643 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3644 PathResolution::new(module.def().unwrap())
3646 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3647 // don't report an error right away, but try to fallback to a primitive type.
3648 // So, we are still able to successfully resolve something like
3650 // use std::u8; // bring module u8 in scope
3651 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3652 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3653 // // not to non-existent std::u8::max_value
3656 // Such behavior is required for backward compatibility.
3657 // The same fallback is used when `a` resolves to nothing.
3658 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3659 PathResult::Failed(..)
3660 if (ns == TypeNS || path.len() > 1) &&
3661 self.primitive_type_table.primitive_types
3662 .contains_key(&path[0].ident.name) => {
3663 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3664 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3666 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3667 PathResolution::new(module.def().unwrap()),
3668 PathResult::Failed(span, msg, false) => {
3669 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3670 err_path_resolution()
3672 PathResult::Module(..) | PathResult::Failed(..) => return None,
3673 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3676 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3677 path[0].ident.name != keywords::CrateRoot.name() &&
3678 path[0].ident.name != keywords::DollarCrate.name() {
3679 let unqualified_result = {
3680 match self.resolve_path_without_parent_scope(
3681 &[*path.last().unwrap()],
3687 PathResult::NonModule(path_res) => path_res.base_def(),
3688 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3689 module.def().unwrap(),
3690 _ => return Some(result),
3693 if result.base_def() == unqualified_result {
3694 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3695 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3702 fn resolve_path_without_parent_scope(
3705 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3708 crate_lint: CrateLint,
3709 ) -> PathResult<'a> {
3710 // Macro and import paths must have full parent scope available during resolution,
3711 // other paths will do okay with parent module alone.
3712 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3713 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3714 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3720 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3721 parent_scope: &ParentScope<'a>,
3724 crate_lint: CrateLint,
3725 ) -> PathResult<'a> {
3726 let mut module = None;
3727 let mut allow_super = true;
3728 let mut second_binding = None;
3729 self.current_module = parent_scope.module;
3732 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3733 path_span={:?}, crate_lint={:?})",
3741 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3742 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3743 let record_segment_def = |this: &mut Self, def| {
3745 if let Some(id) = id {
3746 if !this.def_map.contains_key(&id) {
3747 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3748 this.record_def(id, PathResolution::new(def));
3754 let is_last = i == path.len() - 1;
3755 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3756 let name = ident.name;
3758 allow_super &= ns == TypeNS &&
3759 (name == keywords::SelfValue.name() ||
3760 name == keywords::Super.name());
3763 if allow_super && name == keywords::Super.name() {
3764 let mut ctxt = ident.span.ctxt().modern();
3765 let self_module = match i {
3766 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3768 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3772 if let Some(self_module) = self_module {
3773 if let Some(parent) = self_module.parent {
3774 module = Some(ModuleOrUniformRoot::Module(
3775 self.resolve_self(&mut ctxt, parent)));
3779 let msg = "there are too many initial `super`s.".to_string();
3780 return PathResult::Failed(ident.span, msg, false);
3783 if name == keywords::SelfValue.name() {
3784 let mut ctxt = ident.span.ctxt().modern();
3785 module = Some(ModuleOrUniformRoot::Module(
3786 self.resolve_self(&mut ctxt, self.current_module)));
3789 if name == keywords::Extern.name() ||
3790 name == keywords::CrateRoot.name() && ident.span.rust_2018() {
3791 module = Some(ModuleOrUniformRoot::ExternPrelude);
3794 if name == keywords::CrateRoot.name() ||
3795 name == keywords::Crate.name() ||
3796 name == keywords::DollarCrate.name() {
3797 // `::a::b`, `crate::a::b` or `$crate::a::b`
3798 module = Some(ModuleOrUniformRoot::Module(
3799 self.resolve_crate_root(ident)));
3805 // Report special messages for path segment keywords in wrong positions.
3806 if ident.is_path_segment_keyword() && i != 0 {
3807 let name_str = if name == keywords::CrateRoot.name() {
3808 "crate root".to_string()
3810 format!("`{}`", name)
3812 let msg = if i == 1 && path[0].ident.name == keywords::CrateRoot.name() {
3813 format!("global paths cannot start with {}", name_str)
3815 format!("{} in paths can only be used in start position", name_str)
3817 return PathResult::Failed(ident.span, msg, false);
3820 let binding = if let Some(module) = module {
3821 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3822 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3823 assert!(ns == TypeNS);
3824 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3825 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3826 record_used, path_span)
3828 let record_used_id =
3829 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3830 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3831 // we found a locally-imported or available item/module
3832 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3833 // we found a local variable or type param
3834 Some(LexicalScopeBinding::Def(def))
3835 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3836 record_segment_def(self, def);
3837 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3841 _ => Err(Determinacy::determined(record_used)),
3848 second_binding = Some(binding);
3850 let def = binding.def();
3851 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3852 if let Some(next_module) = binding.module() {
3853 module = Some(ModuleOrUniformRoot::Module(next_module));
3854 record_segment_def(self, def);
3855 } else if def == Def::ToolMod && i + 1 != path.len() {
3856 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3857 return PathResult::NonModule(PathResolution::new(def));
3858 } else if def == Def::Err {
3859 return PathResult::NonModule(err_path_resolution());
3860 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3861 self.lint_if_path_starts_with_module(
3867 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3868 def, path.len() - i - 1
3871 return PathResult::Failed(ident.span,
3872 format!("not a module `{}`", ident),
3876 Err(Undetermined) => return PathResult::Indeterminate,
3877 Err(Determined) => {
3878 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3879 if opt_ns.is_some() && !module.is_normal() {
3880 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3881 module.def().unwrap(), path.len() - i
3885 let module_def = match module {
3886 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3889 let msg = if module_def == self.graph_root.def() {
3890 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3891 let mut candidates =
3892 self.lookup_import_candidates(ident, TypeNS, is_mod);
3893 candidates.sort_by_cached_key(|c| {
3894 (c.path.segments.len(), c.path.to_string())
3896 if let Some(candidate) = candidates.get(0) {
3897 format!("did you mean `{}`?", candidate.path)
3899 format!("maybe a missing `extern crate {};`?", ident)
3902 format!("use of undeclared type or module `{}`", ident)
3904 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
3906 return PathResult::Failed(ident.span, msg, is_last);
3911 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3913 PathResult::Module(match module {
3914 Some(module) => module,
3915 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3916 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3920 fn lint_if_path_starts_with_module(
3922 crate_lint: CrateLint,
3925 second_binding: Option<&NameBinding>,
3927 let (diag_id, diag_span) = match crate_lint {
3928 CrateLint::No => return,
3929 CrateLint::SimplePath(id) => (id, path_span),
3930 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3931 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3934 let first_name = match path.get(0) {
3935 // In the 2018 edition this lint is a hard error, so nothing to do
3936 Some(seg) if seg.ident.span.rust_2015() => seg.ident.name,
3940 // We're only interested in `use` paths which should start with
3941 // `{{root}}` or `extern` currently.
3942 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3947 // If this import looks like `crate::...` it's already good
3948 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3949 // Otherwise go below to see if it's an extern crate
3951 // If the path has length one (and it's `CrateRoot` most likely)
3952 // then we don't know whether we're gonna be importing a crate or an
3953 // item in our crate. Defer this lint to elsewhere
3957 // If the first element of our path was actually resolved to an
3958 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3959 // warning, this looks all good!
3960 if let Some(binding) = second_binding {
3961 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3962 // Careful: we still want to rewrite paths from
3963 // renamed extern crates.
3964 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3970 let diag = lint::builtin::BuiltinLintDiagnostics
3971 ::AbsPathWithModule(diag_span);
3972 self.session.buffer_lint_with_diagnostic(
3973 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3975 "absolute paths must start with `self`, `super`, \
3976 `crate`, or an external crate name in the 2018 edition",
3980 // Resolve a local definition, potentially adjusting for closures.
3981 fn adjust_local_def(&mut self,
3986 span: Span) -> Def {
3987 let ribs = &self.ribs[ns][rib_index + 1..];
3989 // An invalid forward use of a type parameter from a previous default.
3990 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3992 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3994 assert_eq!(def, Def::Err);
4000 span_bug!(span, "unexpected {:?} in bindings", def)
4002 Def::Local(node_id) => {
4005 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4006 ForwardTyParamBanRibKind => {
4007 // Nothing to do. Continue.
4009 ClosureRibKind(function_id) => {
4012 let seen = self.freevars_seen
4015 if let Some(&index) = seen.get(&node_id) {
4016 def = Def::Upvar(node_id, index, function_id);
4019 let vec = self.freevars
4022 let depth = vec.len();
4023 def = Def::Upvar(node_id, depth, function_id);
4030 seen.insert(node_id, depth);
4033 ItemRibKind | TraitOrImplItemRibKind => {
4034 // This was an attempt to access an upvar inside a
4035 // named function item. This is not allowed, so we
4038 resolve_error(self, span,
4039 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4043 ConstantItemRibKind => {
4044 // Still doesn't deal with upvars
4046 resolve_error(self, span,
4047 ResolutionError::AttemptToUseNonConstantValueInConstant);
4054 Def::TyParam(..) | Def::SelfTy(..) => {
4057 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4058 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4059 ConstantItemRibKind => {
4060 // Nothing to do. Continue.
4063 // This was an attempt to use a type parameter outside
4066 resolve_error(self, span,
4067 ResolutionError::TypeParametersFromOuterFunction(def));
4079 fn lookup_assoc_candidate<FilterFn>(&mut self,
4082 filter_fn: FilterFn)
4083 -> Option<AssocSuggestion>
4084 where FilterFn: Fn(Def) -> bool
4086 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4088 TyKind::Path(None, _) => Some(t.id),
4089 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4090 // This doesn't handle the remaining `Ty` variants as they are not
4091 // that commonly the self_type, it might be interesting to provide
4092 // support for those in future.
4097 // Fields are generally expected in the same contexts as locals.
4098 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4099 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4100 // Look for a field with the same name in the current self_type.
4101 if let Some(resolution) = self.def_map.get(&node_id) {
4102 match resolution.base_def() {
4103 Def::Struct(did) | Def::Union(did)
4104 if resolution.unresolved_segments() == 0 => {
4105 if let Some(field_names) = self.field_names.get(&did) {
4106 if field_names.iter().any(|&field_name| ident.name == field_name) {
4107 return Some(AssocSuggestion::Field);
4117 // Look for associated items in the current trait.
4118 if let Some((module, _)) = self.current_trait_ref {
4119 if let Ok(binding) = self.resolve_ident_in_module(
4120 ModuleOrUniformRoot::Module(module),
4127 let def = binding.def();
4129 return Some(if self.has_self.contains(&def.def_id()) {
4130 AssocSuggestion::MethodWithSelf
4132 AssocSuggestion::AssocItem
4141 fn lookup_typo_candidate<FilterFn>(&mut self,
4144 filter_fn: FilterFn,
4147 where FilterFn: Fn(Def) -> bool
4149 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4150 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4151 if let Some(binding) = resolution.borrow().binding {
4152 if filter_fn(binding.def()) {
4153 names.push(ident.name);
4159 let mut names = Vec::new();
4160 if path.len() == 1 {
4161 // Search in lexical scope.
4162 // Walk backwards up the ribs in scope and collect candidates.
4163 for rib in self.ribs[ns].iter().rev() {
4164 // Locals and type parameters
4165 for (ident, def) in &rib.bindings {
4166 if filter_fn(*def) {
4167 names.push(ident.name);
4171 if let ModuleRibKind(module) = rib.kind {
4172 // Items from this module
4173 add_module_candidates(module, &mut names);
4175 if let ModuleKind::Block(..) = module.kind {
4176 // We can see through blocks
4178 // Items from the prelude
4179 if !module.no_implicit_prelude {
4180 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4181 if let Some(prelude) = self.prelude {
4182 add_module_candidates(prelude, &mut names);
4189 // Add primitive types to the mix
4190 if filter_fn(Def::PrimTy(Bool)) {
4192 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4196 // Search in module.
4197 let mod_path = &path[..path.len() - 1];
4198 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4199 mod_path, Some(TypeNS), false, span, CrateLint::No
4201 if let ModuleOrUniformRoot::Module(module) = module {
4202 add_module_candidates(module, &mut names);
4207 let name = path[path.len() - 1].ident.name;
4208 // Make sure error reporting is deterministic.
4209 names.sort_by_cached_key(|name| name.as_str());
4210 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4211 Some(found) if found != name => Some(found),
4216 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4217 where F: FnOnce(&mut Resolver)
4219 if let Some(label) = label {
4220 self.unused_labels.insert(id, label.ident.span);
4221 let def = Def::Label(id);
4222 self.with_label_rib(|this| {
4223 let ident = label.ident.modern_and_legacy();
4224 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4232 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4233 self.with_resolved_label(label, id, |this| this.visit_block(block));
4236 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4237 // First, record candidate traits for this expression if it could
4238 // result in the invocation of a method call.
4240 self.record_candidate_traits_for_expr_if_necessary(expr);
4242 // Next, resolve the node.
4244 ExprKind::Path(ref qself, ref path) => {
4245 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4246 visit::walk_expr(self, expr);
4249 ExprKind::Struct(ref path, ..) => {
4250 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4251 visit::walk_expr(self, expr);
4254 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4255 let def = self.search_label(label.ident, |rib, ident| {
4256 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4260 // Search again for close matches...
4261 // Picks the first label that is "close enough", which is not necessarily
4262 // the closest match
4263 let close_match = self.search_label(label.ident, |rib, ident| {
4264 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4265 find_best_match_for_name(names, &*ident.as_str(), None)
4267 self.record_def(expr.id, err_path_resolution());
4270 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4273 Some(Def::Label(id)) => {
4274 // Since this def is a label, it is never read.
4275 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4276 self.unused_labels.remove(&id);
4279 span_bug!(expr.span, "label wasn't mapped to a label def!");
4283 // visit `break` argument if any
4284 visit::walk_expr(self, expr);
4287 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4288 self.visit_expr(subexpression);
4290 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4291 let mut bindings_list = FxHashMap::default();
4293 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4295 // This has to happen *after* we determine which pat_idents are variants
4296 self.check_consistent_bindings(pats);
4297 self.visit_block(if_block);
4298 self.ribs[ValueNS].pop();
4300 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4303 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4305 ExprKind::While(ref subexpression, ref block, label) => {
4306 self.with_resolved_label(label, expr.id, |this| {
4307 this.visit_expr(subexpression);
4308 this.visit_block(block);
4312 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4313 self.with_resolved_label(label, expr.id, |this| {
4314 this.visit_expr(subexpression);
4315 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4316 let mut bindings_list = FxHashMap::default();
4318 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4320 // This has to happen *after* we determine which pat_idents are variants
4321 this.check_consistent_bindings(pats);
4322 this.visit_block(block);
4323 this.ribs[ValueNS].pop();
4327 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4328 self.visit_expr(subexpression);
4329 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4330 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4332 self.resolve_labeled_block(label, expr.id, block);
4334 self.ribs[ValueNS].pop();
4337 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4339 // Equivalent to `visit::walk_expr` + passing some context to children.
4340 ExprKind::Field(ref subexpression, _) => {
4341 self.resolve_expr(subexpression, Some(expr));
4343 ExprKind::MethodCall(ref segment, ref arguments) => {
4344 let mut arguments = arguments.iter();
4345 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4346 for argument in arguments {
4347 self.resolve_expr(argument, None);
4349 self.visit_path_segment(expr.span, segment);
4352 ExprKind::Call(ref callee, ref arguments) => {
4353 self.resolve_expr(callee, Some(expr));
4354 for argument in arguments {
4355 self.resolve_expr(argument, None);
4358 ExprKind::Type(ref type_expr, _) => {
4359 self.current_type_ascription.push(type_expr.span);
4360 visit::walk_expr(self, expr);
4361 self.current_type_ascription.pop();
4363 // Resolve the body of async exprs inside the async closure to which they desugar
4364 ExprKind::Async(_, async_closure_id, ref block) => {
4365 let rib_kind = ClosureRibKind(async_closure_id);
4366 self.ribs[ValueNS].push(Rib::new(rib_kind));
4367 self.label_ribs.push(Rib::new(rib_kind));
4368 self.visit_block(&block);
4369 self.label_ribs.pop();
4370 self.ribs[ValueNS].pop();
4372 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4373 // resolve the arguments within the proper scopes so that usages of them inside the
4374 // closure are detected as upvars rather than normal closure arg usages.
4376 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4377 ref fn_decl, ref body, _span,
4379 let rib_kind = ClosureRibKind(expr.id);
4380 self.ribs[ValueNS].push(Rib::new(rib_kind));
4381 self.label_ribs.push(Rib::new(rib_kind));
4382 // Resolve arguments:
4383 let mut bindings_list = FxHashMap::default();
4384 for argument in &fn_decl.inputs {
4385 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4386 self.visit_ty(&argument.ty);
4388 // No need to resolve return type-- the outer closure return type is
4389 // FunctionRetTy::Default
4391 // Now resolve the inner closure
4393 let rib_kind = ClosureRibKind(inner_closure_id);
4394 self.ribs[ValueNS].push(Rib::new(rib_kind));
4395 self.label_ribs.push(Rib::new(rib_kind));
4396 // No need to resolve arguments: the inner closure has none.
4397 // Resolve the return type:
4398 visit::walk_fn_ret_ty(self, &fn_decl.output);
4400 self.visit_expr(body);
4401 self.label_ribs.pop();
4402 self.ribs[ValueNS].pop();
4404 self.label_ribs.pop();
4405 self.ribs[ValueNS].pop();
4408 visit::walk_expr(self, expr);
4413 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4415 ExprKind::Field(_, ident) => {
4416 // FIXME(#6890): Even though you can't treat a method like a
4417 // field, we need to add any trait methods we find that match
4418 // the field name so that we can do some nice error reporting
4419 // later on in typeck.
4420 let traits = self.get_traits_containing_item(ident, ValueNS);
4421 self.trait_map.insert(expr.id, traits);
4423 ExprKind::MethodCall(ref segment, ..) => {
4424 debug!("(recording candidate traits for expr) recording traits for {}",
4426 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4427 self.trait_map.insert(expr.id, traits);
4435 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4436 -> Vec<TraitCandidate> {
4437 debug!("(getting traits containing item) looking for '{}'", ident.name);
4439 let mut found_traits = Vec::new();
4440 // Look for the current trait.
4441 if let Some((module, _)) = self.current_trait_ref {
4442 if self.resolve_ident_in_module(
4443 ModuleOrUniformRoot::Module(module),
4450 let def_id = module.def_id().unwrap();
4451 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4455 ident.span = ident.span.modern();
4456 let mut search_module = self.current_module;
4458 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4459 search_module = unwrap_or!(
4460 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4464 if let Some(prelude) = self.prelude {
4465 if !search_module.no_implicit_prelude {
4466 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4473 fn get_traits_in_module_containing_item(&mut self,
4477 found_traits: &mut Vec<TraitCandidate>) {
4478 assert!(ns == TypeNS || ns == ValueNS);
4479 let mut traits = module.traits.borrow_mut();
4480 if traits.is_none() {
4481 let mut collected_traits = Vec::new();
4482 module.for_each_child(|name, ns, binding| {
4483 if ns != TypeNS { return }
4484 if let Def::Trait(_) = binding.def() {
4485 collected_traits.push((name, binding));
4488 *traits = Some(collected_traits.into_boxed_slice());
4491 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4492 let module = binding.module().unwrap();
4493 let mut ident = ident;
4494 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4497 if self.resolve_ident_in_module_unadjusted(
4498 ModuleOrUniformRoot::Module(module),
4504 let import_id = match binding.kind {
4505 NameBindingKind::Import { directive, .. } => {
4506 self.maybe_unused_trait_imports.insert(directive.id);
4507 self.add_to_glob_map(directive.id, trait_name);
4512 let trait_def_id = module.def_id().unwrap();
4513 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4518 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4519 lookup_ident: Ident,
4520 namespace: Namespace,
4521 start_module: &'a ModuleData<'a>,
4523 filter_fn: FilterFn)
4524 -> Vec<ImportSuggestion>
4525 where FilterFn: Fn(Def) -> bool
4527 let mut candidates = Vec::new();
4528 let mut seen_modules = FxHashSet::default();
4529 let not_local_module = crate_name != keywords::Crate.ident();
4530 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4532 while let Some((in_module,
4534 in_module_is_extern)) = worklist.pop() {
4535 self.populate_module_if_necessary(in_module);
4537 // We have to visit module children in deterministic order to avoid
4538 // instabilities in reported imports (#43552).
4539 in_module.for_each_child_stable(|ident, ns, name_binding| {
4540 // avoid imports entirely
4541 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4542 // avoid non-importable candidates as well
4543 if !name_binding.is_importable() { return; }
4545 // collect results based on the filter function
4546 if ident.name == lookup_ident.name && ns == namespace {
4547 if filter_fn(name_binding.def()) {
4549 let mut segms = path_segments.clone();
4550 if lookup_ident.span.rust_2018() {
4551 // crate-local absolute paths start with `crate::` in edition 2018
4552 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4554 0, ast::PathSegment::from_ident(crate_name)
4558 segms.push(ast::PathSegment::from_ident(ident));
4560 span: name_binding.span,
4563 // the entity is accessible in the following cases:
4564 // 1. if it's defined in the same crate, it's always
4565 // accessible (since private entities can be made public)
4566 // 2. if it's defined in another crate, it's accessible
4567 // only if both the module is public and the entity is
4568 // declared as public (due to pruning, we don't explore
4569 // outside crate private modules => no need to check this)
4570 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4571 candidates.push(ImportSuggestion { path });
4576 // collect submodules to explore
4577 if let Some(module) = name_binding.module() {
4579 let mut path_segments = path_segments.clone();
4580 path_segments.push(ast::PathSegment::from_ident(ident));
4582 let is_extern_crate_that_also_appears_in_prelude =
4583 name_binding.is_extern_crate() &&
4584 lookup_ident.span.rust_2018();
4586 let is_visible_to_user =
4587 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4589 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4590 // add the module to the lookup
4591 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4592 if seen_modules.insert(module.def_id().unwrap()) {
4593 worklist.push((module, path_segments, is_extern));
4603 /// When name resolution fails, this method can be used to look up candidate
4604 /// entities with the expected name. It allows filtering them using the
4605 /// supplied predicate (which should be used to only accept the types of
4606 /// definitions expected e.g. traits). The lookup spans across all crates.
4608 /// NOTE: The method does not look into imports, but this is not a problem,
4609 /// since we report the definitions (thus, the de-aliased imports).
4610 fn lookup_import_candidates<FilterFn>(&mut self,
4611 lookup_ident: Ident,
4612 namespace: Namespace,
4613 filter_fn: FilterFn)
4614 -> Vec<ImportSuggestion>
4615 where FilterFn: Fn(Def) -> bool
4617 let mut suggestions = self.lookup_import_candidates_from_module(
4618 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4620 if lookup_ident.span.rust_2018() {
4621 let extern_prelude_names = self.extern_prelude.clone();
4622 for (ident, _) in extern_prelude_names.into_iter() {
4623 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4625 let crate_root = self.get_module(DefId {
4627 index: CRATE_DEF_INDEX,
4629 self.populate_module_if_necessary(&crate_root);
4631 suggestions.extend(self.lookup_import_candidates_from_module(
4632 lookup_ident, namespace, crate_root, ident, &filter_fn));
4640 fn find_module(&mut self,
4642 -> Option<(Module<'a>, ImportSuggestion)>
4644 let mut result = None;
4645 let mut seen_modules = FxHashSet::default();
4646 let mut worklist = vec![(self.graph_root, Vec::new())];
4648 while let Some((in_module, path_segments)) = worklist.pop() {
4649 // abort if the module is already found
4650 if result.is_some() { break; }
4652 self.populate_module_if_necessary(in_module);
4654 in_module.for_each_child_stable(|ident, _, name_binding| {
4655 // abort if the module is already found or if name_binding is private external
4656 if result.is_some() || !name_binding.vis.is_visible_locally() {
4659 if let Some(module) = name_binding.module() {
4661 let mut path_segments = path_segments.clone();
4662 path_segments.push(ast::PathSegment::from_ident(ident));
4663 if module.def() == Some(module_def) {
4665 span: name_binding.span,
4666 segments: path_segments,
4668 result = Some((module, ImportSuggestion { path }));
4670 // add the module to the lookup
4671 if seen_modules.insert(module.def_id().unwrap()) {
4672 worklist.push((module, path_segments));
4682 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4683 if let Def::Enum(..) = enum_def {} else {
4684 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4687 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4688 self.populate_module_if_necessary(enum_module);
4690 let mut variants = Vec::new();
4691 enum_module.for_each_child_stable(|ident, _, name_binding| {
4692 if let Def::Variant(..) = name_binding.def() {
4693 let mut segms = enum_import_suggestion.path.segments.clone();
4694 segms.push(ast::PathSegment::from_ident(ident));
4695 variants.push(Path {
4696 span: name_binding.span,
4705 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4706 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4707 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4708 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4712 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4714 ast::VisibilityKind::Public => ty::Visibility::Public,
4715 ast::VisibilityKind::Crate(..) => {
4716 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4718 ast::VisibilityKind::Inherited => {
4719 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4721 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4722 // For visibilities we are not ready to provide correct implementation of "uniform
4723 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4724 // On 2015 edition visibilities are resolved as crate-relative by default,
4725 // so we are prepending a root segment if necessary.
4726 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4727 let crate_root = if ident.is_path_segment_keyword() {
4729 } else if ident.span.rust_2018() {
4730 let msg = "relative paths are not supported in visibilities on 2018 edition";
4731 self.session.struct_span_err(ident.span, msg)
4732 .span_suggestion(path.span, "try", format!("crate::{}", path))
4734 return ty::Visibility::Public;
4736 let ctxt = ident.span.ctxt();
4737 Some(Segment::from_ident(Ident::new(
4738 keywords::CrateRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4742 let segments = crate_root.into_iter()
4743 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4744 let def = self.smart_resolve_path_fragment(
4749 PathSource::Visibility,
4750 CrateLint::SimplePath(id),
4752 if def == Def::Err {
4753 ty::Visibility::Public
4755 let vis = ty::Visibility::Restricted(def.def_id());
4756 if self.is_accessible(vis) {
4759 self.session.span_err(path.span, "visibilities can only be restricted \
4760 to ancestor modules");
4761 ty::Visibility::Public
4768 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4769 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4772 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4773 vis.is_accessible_from(module.normal_ancestor_id, self)
4776 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4777 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4778 if !ptr::eq(module, old_module) {
4779 span_bug!(binding.span, "parent module is reset for binding");
4784 fn disambiguate_legacy_vs_modern(
4786 legacy: &'a NameBinding<'a>,
4787 modern: &'a NameBinding<'a>,
4789 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4790 // is disambiguated to mitigate regressions from macro modularization.
4791 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4792 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4793 self.binding_parent_modules.get(&PtrKey(modern))) {
4794 (Some(legacy), Some(modern)) =>
4795 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4796 modern.is_ancestor_of(legacy),
4801 fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
4802 if b.span.is_dummy() {
4803 let add_built_in = match b.def() {
4804 // These already contain the "built-in" prefix or look bad with it.
4805 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4808 let (built_in, from) = if from_prelude {
4809 ("", " from prelude")
4810 } else if b.is_extern_crate() && !b.is_import() &&
4811 self.session.opts.externs.get(&ident.as_str()).is_some() {
4812 ("", " passed with `--extern`")
4813 } else if add_built_in {
4819 let article = if built_in.is_empty() { b.article() } else { "a" };
4820 format!("{a}{built_in} {thing}{from}",
4821 a = article, thing = b.descr(), built_in = built_in, from = from)
4823 let introduced = if b.is_import() { "imported" } else { "defined" };
4824 format!("the {thing} {introduced} here",
4825 thing = b.descr(), introduced = introduced)
4829 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
4830 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4831 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4832 // We have to print the span-less alternative first, otherwise formatting looks bad.
4833 (b2, b1, misc2, misc1, true)
4835 (b1, b2, misc1, misc2, false)
4838 let mut err = struct_span_err!(self.session, ident.span, E0659,
4839 "`{ident}` is ambiguous ({why})",
4840 ident = ident, why = kind.descr());
4841 err.span_label(ident.span, "ambiguous name");
4843 let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
4844 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4845 let note_msg = format!("`{ident}` could{also} refer to {what}",
4846 ident = ident, also = also, what = what);
4848 let mut help_msgs = Vec::new();
4849 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4850 kind == AmbiguityKind::GlobVsExpanded ||
4851 kind == AmbiguityKind::GlobVsOuter &&
4852 swapped != also.is_empty()) {
4853 help_msgs.push(format!("consider adding an explicit import of \
4854 `{ident}` to disambiguate", ident = ident))
4856 if b.is_extern_crate() && ident.span.rust_2018() {
4857 help_msgs.push(format!("use `::{ident}` to refer to this {thing} unambiguously",
4858 ident = ident, thing = b.descr()))
4860 if misc == AmbiguityErrorMisc::SuggestSelf {
4861 help_msgs.push(format!("use `self::{ident}` to refer to this {thing} unambiguously",
4862 ident = ident, thing = b.descr()))
4865 if b.span.is_dummy() {
4866 err.note(¬e_msg);
4868 err.span_note(b.span, ¬e_msg);
4870 for (i, help_msg) in help_msgs.iter().enumerate() {
4871 let or = if i == 0 { "" } else { "or " };
4872 err.help(&format!("{}{}", or, help_msg));
4876 could_refer_to(b1, misc1, "");
4877 could_refer_to(b2, misc2, " also");
4881 fn report_errors(&mut self, krate: &Crate) {
4882 self.report_with_use_injections(krate);
4884 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4885 let msg = "macro-expanded `macro_export` macros from the current crate \
4886 cannot be referred to by absolute paths";
4887 self.session.buffer_lint_with_diagnostic(
4888 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4889 CRATE_NODE_ID, span_use, msg,
4890 lint::builtin::BuiltinLintDiagnostics::
4891 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4895 for ambiguity_error in &self.ambiguity_errors {
4896 self.report_ambiguity_error(ambiguity_error);
4899 let mut reported_spans = FxHashSet::default();
4900 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4901 if reported_spans.insert(dedup_span) {
4902 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4903 binding.descr(), ident.name);
4908 fn report_with_use_injections(&mut self, krate: &Crate) {
4909 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4910 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4911 if !candidates.is_empty() {
4912 show_candidates(&mut err, span, &candidates, better, found_use);
4918 fn report_conflict<'b>(&mut self,
4922 new_binding: &NameBinding<'b>,
4923 old_binding: &NameBinding<'b>) {
4924 // Error on the second of two conflicting names
4925 if old_binding.span.lo() > new_binding.span.lo() {
4926 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4929 let container = match parent.kind {
4930 ModuleKind::Def(Def::Mod(_), _) => "module",
4931 ModuleKind::Def(Def::Trait(_), _) => "trait",
4932 ModuleKind::Block(..) => "block",
4936 let old_noun = match old_binding.is_import() {
4938 false => "definition",
4941 let new_participle = match new_binding.is_import() {
4946 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4948 if let Some(s) = self.name_already_seen.get(&name) {
4954 let old_kind = match (ns, old_binding.module()) {
4955 (ValueNS, _) => "value",
4956 (MacroNS, _) => "macro",
4957 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4958 (TypeNS, Some(module)) if module.is_normal() => "module",
4959 (TypeNS, Some(module)) if module.is_trait() => "trait",
4960 (TypeNS, _) => "type",
4963 let msg = format!("the name `{}` is defined multiple times", name);
4965 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4966 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4967 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4968 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4969 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4971 _ => match (old_binding.is_import(), new_binding.is_import()) {
4972 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4973 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4974 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4978 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4983 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4984 if !old_binding.span.is_dummy() {
4985 err.span_label(self.session.source_map().def_span(old_binding.span),
4986 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4989 // See https://github.com/rust-lang/rust/issues/32354
4990 if old_binding.is_import() || new_binding.is_import() {
4991 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4997 let cm = self.session.source_map();
4998 let rename_msg = "you can use `as` to change the binding name of the import";
5002 NameBindingKind::Import { directive, ..},
5005 cm.span_to_snippet(binding.span),
5006 binding.kind.clone(),
5007 binding.span.is_dummy(),
5009 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5010 format!("Other{}", name)
5012 format!("other_{}", name)
5015 err.span_suggestion_with_applicability(
5018 match directive.subclass {
5019 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5020 format!("self as {}", suggested_name),
5021 ImportDirectiveSubclass::SingleImport { source, .. } =>
5024 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
5026 if snippet.ends_with(";") {
5032 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5034 "extern crate {} as {};",
5035 source.unwrap_or(target.name),
5038 _ => unreachable!(),
5040 Applicability::MaybeIncorrect,
5043 err.span_label(binding.span, rename_msg);
5048 self.name_already_seen.insert(name, span);
5051 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5052 -> Option<&'a NameBinding<'a>> {
5053 if ident.is_path_segment_keyword() {
5054 // Make sure `self`, `super` etc produce an error when passed to here.
5057 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5058 if let Some(binding) = entry.extern_crate_item {
5061 let crate_id = if !speculative {
5062 self.crate_loader.process_path_extern(ident.name, ident.span)
5063 } else if let Some(crate_id) =
5064 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5069 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5070 self.populate_module_if_necessary(&crate_root);
5071 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5072 .to_name_binding(self.arenas))
5078 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5079 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfType.name()
5082 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5083 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfValue.name()
5086 fn names_to_string(idents: &[Ident]) -> String {
5087 let mut result = String::new();
5088 for (i, ident) in idents.iter()
5089 .filter(|ident| ident.name != keywords::CrateRoot.name())
5092 result.push_str("::");
5094 result.push_str(&ident.as_str());
5099 fn path_names_to_string(path: &Path) -> String {
5100 names_to_string(&path.segments.iter()
5101 .map(|seg| seg.ident)
5102 .collect::<Vec<_>>())
5105 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
5106 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
5107 let variant_path = &suggestion.path;
5108 let variant_path_string = path_names_to_string(variant_path);
5110 let path_len = suggestion.path.segments.len();
5111 let enum_path = ast::Path {
5112 span: suggestion.path.span,
5113 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5115 let enum_path_string = path_names_to_string(&enum_path);
5117 (suggestion.path.span, variant_path_string, enum_path_string)
5121 /// When an entity with a given name is not available in scope, we search for
5122 /// entities with that name in all crates. This method allows outputting the
5123 /// results of this search in a programmer-friendly way
5124 fn show_candidates(err: &mut DiagnosticBuilder,
5125 // This is `None` if all placement locations are inside expansions
5127 candidates: &[ImportSuggestion],
5131 // we want consistent results across executions, but candidates are produced
5132 // by iterating through a hash map, so make sure they are ordered:
5133 let mut path_strings: Vec<_> =
5134 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5135 path_strings.sort();
5137 let better = if better { "better " } else { "" };
5138 let msg_diff = match path_strings.len() {
5139 1 => " is found in another module, you can import it",
5140 _ => "s are found in other modules, you can import them",
5142 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5144 if let Some(span) = span {
5145 for candidate in &mut path_strings {
5146 // produce an additional newline to separate the new use statement
5147 // from the directly following item.
5148 let additional_newline = if found_use {
5153 *candidate = format!("use {};\n{}", candidate, additional_newline);
5156 err.span_suggestions_with_applicability(
5159 path_strings.into_iter(),
5160 Applicability::Unspecified,
5165 for candidate in path_strings {
5167 msg.push_str(&candidate);
5172 /// A somewhat inefficient routine to obtain the name of a module.
5173 fn module_to_string(module: Module) -> Option<String> {
5174 let mut names = Vec::new();
5176 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5177 if let ModuleKind::Def(_, name) = module.kind {
5178 if let Some(parent) = module.parent {
5179 names.push(Ident::with_empty_ctxt(name));
5180 collect_mod(names, parent);
5183 // danger, shouldn't be ident?
5184 names.push(Ident::from_str("<opaque>"));
5185 collect_mod(names, module.parent.unwrap());
5188 collect_mod(&mut names, module);
5190 if names.is_empty() {
5193 Some(names_to_string(&names.into_iter()
5195 .collect::<Vec<_>>()))
5198 fn err_path_resolution() -> PathResolution {
5199 PathResolution::new(Def::Err)
5202 #[derive(PartialEq,Copy, Clone)]
5203 pub enum MakeGlobMap {
5208 #[derive(Copy, Clone, Debug)]
5210 /// Do not issue the lint
5213 /// This lint applies to some random path like `impl ::foo::Bar`
5214 /// or whatever. In this case, we can take the span of that path.
5217 /// This lint comes from a `use` statement. In this case, what we
5218 /// care about really is the *root* `use` statement; e.g., if we
5219 /// have nested things like `use a::{b, c}`, we care about the
5221 UsePath { root_id: NodeId, root_span: Span },
5223 /// This is the "trait item" from a fully qualified path. For example,
5224 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5225 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5226 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5230 fn node_id(&self) -> Option<NodeId> {
5232 CrateLint::No => None,
5233 CrateLint::SimplePath(id) |
5234 CrateLint::UsePath { root_id: id, .. } |
5235 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5240 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }