1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
17 #![feature(rustc_diagnostic_macros)]
18 #![feature(slice_sort_by_cached_key)]
24 extern crate syntax_pos;
25 extern crate rustc_errors as errors;
29 extern crate rustc_data_structures;
30 extern crate rustc_metadata;
32 pub use rustc::hir::def::{Namespace, PerNS};
34 use self::TypeParameters::*;
37 use rustc::hir::map::{Definitions, DefCollector};
38 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
39 use rustc::middle::cstore::CrateStore;
40 use rustc::session::Session;
42 use rustc::hir::def::*;
43 use rustc::hir::def::Namespace::*;
44 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
45 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
46 use rustc::session::config::nightly_options;
48 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
50 use rustc_metadata::creader::CrateLoader;
51 use rustc_metadata::cstore::CStore;
53 use syntax::source_map::SourceMap;
54 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
55 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
56 use syntax::ext::base::SyntaxExtension;
57 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
58 use syntax::ext::base::MacroKind;
59 use syntax::symbol::{Symbol, keywords};
60 use syntax::util::lev_distance::find_best_match_for_name;
62 use syntax::visit::{self, FnKind, Visitor};
64 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
65 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
66 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
67 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
68 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
71 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
72 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
74 use std::cell::{Cell, RefCell};
76 use std::collections::BTreeSet;
79 use std::mem::replace;
80 use rustc_data_structures::sync::Lrc;
82 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
83 use macros::{InvocationData, LegacyBinding, ParentScope};
85 // NB: This module needs to be declared first so diagnostics are
86 // registered before they are used.
91 mod build_reduced_graph;
94 fn is_known_tool(name: Name) -> bool {
95 ["clippy", "rustfmt"].contains(&&*name.as_str())
98 /// A free importable items suggested in case of resolution failure.
99 struct ImportSuggestion {
103 /// A field or associated item from self type suggested in case of resolution failure.
104 enum AssocSuggestion {
111 struct BindingError {
113 origin: BTreeSet<Span>,
114 target: BTreeSet<Span>,
117 impl PartialOrd for BindingError {
118 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
119 Some(self.cmp(other))
123 impl PartialEq for BindingError {
124 fn eq(&self, other: &BindingError) -> bool {
125 self.name == other.name
129 impl Ord for BindingError {
130 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
131 self.name.cmp(&other.name)
135 enum ResolutionError<'a> {
136 /// error E0401: can't use type parameters from outer function
137 TypeParametersFromOuterFunction(Def),
138 /// error E0403: the name is already used for a type parameter in this type parameter list
139 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
140 /// error E0407: method is not a member of trait
141 MethodNotMemberOfTrait(Name, &'a str),
142 /// error E0437: type is not a member of trait
143 TypeNotMemberOfTrait(Name, &'a str),
144 /// error E0438: const is not a member of trait
145 ConstNotMemberOfTrait(Name, &'a str),
146 /// error E0408: variable `{}` is not bound in all patterns
147 VariableNotBoundInPattern(&'a BindingError),
148 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
149 VariableBoundWithDifferentMode(Name, Span),
150 /// error E0415: identifier is bound more than once in this parameter list
151 IdentifierBoundMoreThanOnceInParameterList(&'a str),
152 /// error E0416: identifier is bound more than once in the same pattern
153 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
154 /// error E0426: use of undeclared label
155 UndeclaredLabel(&'a str, Option<Name>),
156 /// error E0429: `self` imports are only allowed within a { } list
157 SelfImportsOnlyAllowedWithin,
158 /// error E0430: `self` import can only appear once in the list
159 SelfImportCanOnlyAppearOnceInTheList,
160 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
161 SelfImportOnlyInImportListWithNonEmptyPrefix,
162 /// error E0433: failed to resolve
163 FailedToResolve(&'a str),
164 /// error E0434: can't capture dynamic environment in a fn item
165 CannotCaptureDynamicEnvironmentInFnItem,
166 /// error E0435: attempt to use a non-constant value in a constant
167 AttemptToUseNonConstantValueInConstant,
168 /// error E0530: X bindings cannot shadow Ys
169 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
170 /// error E0128: type parameters with a default cannot use forward declared identifiers
171 ForwardDeclaredTyParam,
174 /// Combines an error with provided span and emits it
176 /// This takes the error provided, combines it with the span and any additional spans inside the
177 /// error and emits it.
178 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
180 resolution_error: ResolutionError<'a>) {
181 resolve_struct_error(resolver, span, resolution_error).emit();
184 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
186 resolution_error: ResolutionError<'a>)
187 -> DiagnosticBuilder<'sess> {
188 match resolution_error {
189 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
190 let mut err = struct_span_err!(resolver.session,
193 "can't use type parameters from outer function");
194 err.span_label(span, "use of type variable from outer function");
196 let cm = resolver.session.source_map();
198 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
199 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
200 resolver.definitions.opt_span(def_id)
203 reduce_impl_span_to_impl_keyword(cm, impl_span),
204 "`Self` type implicitly declared here, by this `impl`",
207 match (maybe_trait_defid, maybe_impl_defid) {
209 err.span_label(span, "can't use `Self` here");
212 err.span_label(span, "use a type here instead");
214 (None, None) => bug!("`impl` without trait nor type?"),
218 Def::TyParam(typaram_defid) => {
219 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
220 err.span_label(typaram_span, "type variable from outer function");
224 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
229 // Try to retrieve the span of the function signature and generate a new message with
230 // a local type parameter
231 let sugg_msg = "try using a local type parameter instead";
232 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
233 // Suggest the modification to the user
234 err.span_suggestion_with_applicability(
238 Applicability::MachineApplicable,
240 } else if let Some(sp) = cm.generate_fn_name_span(span) {
241 err.span_label(sp, "try adding a local type parameter in this method instead");
243 err.help("try using a local type parameter instead");
248 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
249 let mut err = struct_span_err!(resolver.session,
252 "the name `{}` is already used for a type parameter \
253 in this type parameter list",
255 err.span_label(span, "already used");
256 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
259 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
260 let mut err = struct_span_err!(resolver.session,
263 "method `{}` is not a member of trait `{}`",
266 err.span_label(span, format!("not a member of trait `{}`", trait_));
269 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
270 let mut err = struct_span_err!(resolver.session,
273 "type `{}` is not a member of trait `{}`",
276 err.span_label(span, format!("not a member of trait `{}`", trait_));
279 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
280 let mut err = struct_span_err!(resolver.session,
283 "const `{}` is not a member of trait `{}`",
286 err.span_label(span, format!("not a member of trait `{}`", trait_));
289 ResolutionError::VariableNotBoundInPattern(binding_error) => {
290 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
291 let msp = MultiSpan::from_spans(target_sp.clone());
292 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
293 let mut err = resolver.session.struct_span_err_with_code(
296 DiagnosticId::Error("E0408".into()),
298 for sp in target_sp {
299 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
301 let origin_sp = binding_error.origin.iter().cloned();
302 for sp in origin_sp {
303 err.span_label(sp, "variable not in all patterns");
307 ResolutionError::VariableBoundWithDifferentMode(variable_name,
308 first_binding_span) => {
309 let mut err = struct_span_err!(resolver.session,
312 "variable `{}` is bound in inconsistent \
313 ways within the same match arm",
315 err.span_label(span, "bound in different ways");
316 err.span_label(first_binding_span, "first binding");
319 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
320 let mut err = struct_span_err!(resolver.session,
323 "identifier `{}` is bound more than once in this parameter list",
325 err.span_label(span, "used as parameter more than once");
328 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
329 let mut err = struct_span_err!(resolver.session,
332 "identifier `{}` is bound more than once in the same pattern",
334 err.span_label(span, "used in a pattern more than once");
337 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
338 let mut err = struct_span_err!(resolver.session,
341 "use of undeclared label `{}`",
343 if let Some(lev_candidate) = lev_candidate {
344 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
346 err.span_label(span, format!("undeclared label `{}`", name));
350 ResolutionError::SelfImportsOnlyAllowedWithin => {
351 struct_span_err!(resolver.session,
355 "`self` imports are only allowed within a { } list")
357 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
358 let mut err = struct_span_err!(resolver.session, span, E0430,
359 "`self` import can only appear once in an import list");
360 err.span_label(span, "can only appear once in an import list");
363 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
364 let mut err = struct_span_err!(resolver.session, span, E0431,
365 "`self` import can only appear in an import list with \
366 a non-empty prefix");
367 err.span_label(span, "can only appear in an import list with a non-empty prefix");
370 ResolutionError::FailedToResolve(msg) => {
371 let mut err = struct_span_err!(resolver.session, span, E0433,
372 "failed to resolve. {}", msg);
373 err.span_label(span, msg);
376 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
377 let mut err = struct_span_err!(resolver.session,
381 "can't capture dynamic environment in a fn item");
382 err.help("use the `|| { ... }` closure form instead");
385 ResolutionError::AttemptToUseNonConstantValueInConstant => {
386 let mut err = struct_span_err!(resolver.session, span, E0435,
387 "attempt to use a non-constant value in a constant");
388 err.span_label(span, "non-constant value");
391 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
392 let shadows_what = PathResolution::new(binding.def()).kind_name();
393 let mut err = struct_span_err!(resolver.session,
396 "{}s cannot shadow {}s", what_binding, shadows_what);
397 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
398 let participle = if binding.is_import() { "imported" } else { "defined" };
399 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
400 err.span_label(binding.span, msg);
403 ResolutionError::ForwardDeclaredTyParam => {
404 let mut err = struct_span_err!(resolver.session, span, E0128,
405 "type parameters with a default cannot use \
406 forward declared identifiers");
408 span, "defaulted type parameters cannot be forward declared".to_string());
414 /// Adjust the impl span so that just the `impl` keyword is taken by removing
415 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
416 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
418 /// Attention: The method used is very fragile since it essentially duplicates the work of the
419 /// parser. If you need to use this function or something similar, please consider updating the
420 /// source_map functions and this function to something more robust.
421 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
422 let impl_span = cm.span_until_char(impl_span, '<');
423 let impl_span = cm.span_until_whitespace(impl_span);
427 #[derive(Copy, Clone, Debug)]
430 binding_mode: BindingMode,
433 /// Map from the name in a pattern to its binding mode.
434 type BindingMap = FxHashMap<Ident, BindingInfo>;
436 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
447 fn descr(self) -> &'static str {
449 PatternSource::Match => "match binding",
450 PatternSource::IfLet => "if let binding",
451 PatternSource::WhileLet => "while let binding",
452 PatternSource::Let => "let binding",
453 PatternSource::For => "for binding",
454 PatternSource::FnParam => "function parameter",
459 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
460 enum AliasPossibility {
465 #[derive(Copy, Clone, Debug)]
466 enum PathSource<'a> {
467 // Type paths `Path`.
469 // Trait paths in bounds or impls.
470 Trait(AliasPossibility),
471 // Expression paths `path`, with optional parent context.
472 Expr(Option<&'a Expr>),
473 // Paths in path patterns `Path`.
475 // Paths in struct expressions and patterns `Path { .. }`.
477 // Paths in tuple struct patterns `Path(..)`.
479 // `m::A::B` in `<T as m::A>::B::C`.
480 TraitItem(Namespace),
481 // Path in `pub(path)`
483 // Path in `use a::b::{...};`
487 impl<'a> PathSource<'a> {
488 fn namespace(self) -> Namespace {
490 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
491 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
492 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
493 PathSource::TraitItem(ns) => ns,
497 fn global_by_default(self) -> bool {
499 PathSource::Visibility | PathSource::ImportPrefix => true,
500 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
501 PathSource::Struct | PathSource::TupleStruct |
502 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
506 fn defer_to_typeck(self) -> bool {
508 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
509 PathSource::Struct | PathSource::TupleStruct => true,
510 PathSource::Trait(_) | PathSource::TraitItem(..) |
511 PathSource::Visibility | PathSource::ImportPrefix => false,
515 fn descr_expected(self) -> &'static str {
517 PathSource::Type => "type",
518 PathSource::Trait(_) => "trait",
519 PathSource::Pat => "unit struct/variant or constant",
520 PathSource::Struct => "struct, variant or union type",
521 PathSource::TupleStruct => "tuple struct/variant",
522 PathSource::Visibility => "module",
523 PathSource::ImportPrefix => "module or enum",
524 PathSource::TraitItem(ns) => match ns {
525 TypeNS => "associated type",
526 ValueNS => "method or associated constant",
527 MacroNS => bug!("associated macro"),
529 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
530 // "function" here means "anything callable" rather than `Def::Fn`,
531 // this is not precise but usually more helpful than just "value".
532 Some(&ExprKind::Call(..)) => "function",
538 fn is_expected(self, def: Def) -> bool {
540 PathSource::Type => match def {
541 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
542 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
543 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
544 Def::Existential(..) |
545 Def::ForeignTy(..) => true,
548 PathSource::Trait(AliasPossibility::No) => match def {
549 Def::Trait(..) => true,
552 PathSource::Trait(AliasPossibility::Maybe) => match def {
553 Def::Trait(..) => true,
554 Def::TraitAlias(..) => true,
557 PathSource::Expr(..) => match def {
558 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
559 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
560 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
561 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
562 Def::SelfCtor(..) => true,
565 PathSource::Pat => match def {
566 Def::StructCtor(_, CtorKind::Const) |
567 Def::VariantCtor(_, CtorKind::Const) |
568 Def::Const(..) | Def::AssociatedConst(..) |
569 Def::SelfCtor(..) => true,
572 PathSource::TupleStruct => match def {
573 Def::StructCtor(_, CtorKind::Fn) |
574 Def::VariantCtor(_, CtorKind::Fn) |
575 Def::SelfCtor(..) => true,
578 PathSource::Struct => match def {
579 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
580 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
583 PathSource::TraitItem(ns) => match def {
584 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
585 Def::AssociatedTy(..) if ns == TypeNS => true,
588 PathSource::ImportPrefix => match def {
589 Def::Mod(..) | Def::Enum(..) => true,
592 PathSource::Visibility => match def {
593 Def::Mod(..) => true,
599 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
600 __diagnostic_used!(E0404);
601 __diagnostic_used!(E0405);
602 __diagnostic_used!(E0412);
603 __diagnostic_used!(E0422);
604 __diagnostic_used!(E0423);
605 __diagnostic_used!(E0425);
606 __diagnostic_used!(E0531);
607 __diagnostic_used!(E0532);
608 __diagnostic_used!(E0573);
609 __diagnostic_used!(E0574);
610 __diagnostic_used!(E0575);
611 __diagnostic_used!(E0576);
612 __diagnostic_used!(E0577);
613 __diagnostic_used!(E0578);
614 match (self, has_unexpected_resolution) {
615 (PathSource::Trait(_), true) => "E0404",
616 (PathSource::Trait(_), false) => "E0405",
617 (PathSource::Type, true) => "E0573",
618 (PathSource::Type, false) => "E0412",
619 (PathSource::Struct, true) => "E0574",
620 (PathSource::Struct, false) => "E0422",
621 (PathSource::Expr(..), true) => "E0423",
622 (PathSource::Expr(..), false) => "E0425",
623 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
624 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
625 (PathSource::TraitItem(..), true) => "E0575",
626 (PathSource::TraitItem(..), false) => "E0576",
627 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
628 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
633 struct UsePlacementFinder {
634 target_module: NodeId,
639 impl UsePlacementFinder {
640 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
641 let mut finder = UsePlacementFinder {
646 visit::walk_crate(&mut finder, krate);
647 (finder.span, finder.found_use)
651 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
654 module: &'tcx ast::Mod,
656 _: &[ast::Attribute],
659 if self.span.is_some() {
662 if node_id != self.target_module {
663 visit::walk_mod(self, module);
666 // find a use statement
667 for item in &module.items {
669 ItemKind::Use(..) => {
670 // don't suggest placing a use before the prelude
671 // import or other generated ones
672 if item.span.ctxt().outer().expn_info().is_none() {
673 self.span = Some(item.span.shrink_to_lo());
674 self.found_use = true;
678 // don't place use before extern crate
679 ItemKind::ExternCrate(_) => {}
680 // but place them before the first other item
681 _ => if self.span.map_or(true, |span| item.span < span ) {
682 if item.span.ctxt().outer().expn_info().is_none() {
683 // don't insert between attributes and an item
684 if item.attrs.is_empty() {
685 self.span = Some(item.span.shrink_to_lo());
687 // find the first attribute on the item
688 for attr in &item.attrs {
689 if self.span.map_or(true, |span| attr.span < span) {
690 self.span = Some(attr.span.shrink_to_lo());
701 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
702 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
703 fn visit_item(&mut self, item: &'tcx Item) {
704 self.resolve_item(item);
706 fn visit_arm(&mut self, arm: &'tcx Arm) {
707 self.resolve_arm(arm);
709 fn visit_block(&mut self, block: &'tcx Block) {
710 self.resolve_block(block);
712 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
713 self.with_constant_rib(|this| {
714 visit::walk_anon_const(this, constant);
717 fn visit_expr(&mut self, expr: &'tcx Expr) {
718 self.resolve_expr(expr, None);
720 fn visit_local(&mut self, local: &'tcx Local) {
721 self.resolve_local(local);
723 fn visit_ty(&mut self, ty: &'tcx Ty) {
725 TyKind::Path(ref qself, ref path) => {
726 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
728 TyKind::ImplicitSelf => {
729 let self_ty = keywords::SelfType.ident();
730 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
731 .map_or(Def::Err, |d| d.def());
732 self.record_def(ty.id, PathResolution::new(def));
736 visit::walk_ty(self, ty);
738 fn visit_poly_trait_ref(&mut self,
739 tref: &'tcx ast::PolyTraitRef,
740 m: &'tcx ast::TraitBoundModifier) {
741 self.smart_resolve_path(tref.trait_ref.ref_id, None,
742 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
743 visit::walk_poly_trait_ref(self, tref, m);
745 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
746 let type_parameters = match foreign_item.node {
747 ForeignItemKind::Fn(_, ref generics) => {
748 HasTypeParameters(generics, ItemRibKind)
750 ForeignItemKind::Static(..) => NoTypeParameters,
751 ForeignItemKind::Ty => NoTypeParameters,
752 ForeignItemKind::Macro(..) => NoTypeParameters,
754 self.with_type_parameter_rib(type_parameters, |this| {
755 visit::walk_foreign_item(this, foreign_item);
758 fn visit_fn(&mut self,
759 function_kind: FnKind<'tcx>,
760 declaration: &'tcx FnDecl,
764 let (rib_kind, asyncness) = match function_kind {
765 FnKind::ItemFn(_, ref header, ..) =>
766 (ItemRibKind, header.asyncness),
767 FnKind::Method(_, ref sig, _, _) =>
768 (TraitOrImplItemRibKind, sig.header.asyncness),
769 FnKind::Closure(_) =>
770 // Async closures aren't resolved through `visit_fn`-- they're
771 // processed separately
772 (ClosureRibKind(node_id), IsAsync::NotAsync),
775 // Create a value rib for the function.
776 self.ribs[ValueNS].push(Rib::new(rib_kind));
778 // Create a label rib for the function.
779 self.label_ribs.push(Rib::new(rib_kind));
781 // Add each argument to the rib.
782 let mut bindings_list = FxHashMap();
783 for argument in &declaration.inputs {
784 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
786 self.visit_ty(&argument.ty);
788 debug!("(resolving function) recorded argument");
790 visit::walk_fn_ret_ty(self, &declaration.output);
792 // Resolve the function body, potentially inside the body of an async closure
793 if let IsAsync::Async { closure_id, .. } = asyncness {
794 let rib_kind = ClosureRibKind(closure_id);
795 self.ribs[ValueNS].push(Rib::new(rib_kind));
796 self.label_ribs.push(Rib::new(rib_kind));
799 match function_kind {
800 FnKind::ItemFn(.., body) |
801 FnKind::Method(.., body) => {
802 self.visit_block(body);
804 FnKind::Closure(body) => {
805 self.visit_expr(body);
809 // Leave the body of the async closure
810 if asyncness.is_async() {
811 self.label_ribs.pop();
812 self.ribs[ValueNS].pop();
815 debug!("(resolving function) leaving function");
817 self.label_ribs.pop();
818 self.ribs[ValueNS].pop();
820 fn visit_generics(&mut self, generics: &'tcx Generics) {
821 // For type parameter defaults, we have to ban access
822 // to following type parameters, as the Substs can only
823 // provide previous type parameters as they're built. We
824 // put all the parameters on the ban list and then remove
825 // them one by one as they are processed and become available.
826 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
827 let mut found_default = false;
828 default_ban_rib.bindings.extend(generics.params.iter()
829 .filter_map(|param| match param.kind {
830 GenericParamKind::Lifetime { .. } => None,
831 GenericParamKind::Type { ref default, .. } => {
832 found_default |= default.is_some();
834 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
841 for param in &generics.params {
843 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
844 GenericParamKind::Type { ref default, .. } => {
845 for bound in ¶m.bounds {
846 self.visit_param_bound(bound);
849 if let Some(ref ty) = default {
850 self.ribs[TypeNS].push(default_ban_rib);
852 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
855 // Allow all following defaults to refer to this type parameter.
856 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
860 for p in &generics.where_clause.predicates {
861 self.visit_where_predicate(p);
866 #[derive(Copy, Clone)]
867 enum TypeParameters<'a, 'b> {
869 HasTypeParameters(// Type parameters.
872 // The kind of the rib used for type parameters.
876 /// The rib kind controls the translation of local
877 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
878 #[derive(Copy, Clone, Debug)]
880 /// No translation needs to be applied.
883 /// We passed through a closure scope at the given node ID.
884 /// Translate upvars as appropriate.
885 ClosureRibKind(NodeId /* func id */),
887 /// We passed through an impl or trait and are now in one of its
888 /// methods or associated types. Allow references to ty params that impl or trait
889 /// binds. Disallow any other upvars (including other ty params that are
891 TraitOrImplItemRibKind,
893 /// We passed through an item scope. Disallow upvars.
896 /// We're in a constant item. Can't refer to dynamic stuff.
899 /// We passed through a module.
900 ModuleRibKind(Module<'a>),
902 /// We passed through a `macro_rules!` statement
903 MacroDefinition(DefId),
905 /// All bindings in this rib are type parameters that can't be used
906 /// from the default of a type parameter because they're not declared
907 /// before said type parameter. Also see the `visit_generics` override.
908 ForwardTyParamBanRibKind,
913 /// A rib represents a scope names can live in. Note that these appear in many places, not just
914 /// around braces. At any place where the list of accessible names (of the given namespace)
915 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
916 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
919 /// Different [rib kinds](enum.RibKind) are transparent for different names.
921 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
922 /// resolving, the name is looked up from inside out.
925 bindings: FxHashMap<Ident, Def>,
930 fn new(kind: RibKind<'a>) -> Rib<'a> {
932 bindings: FxHashMap(),
938 /// An intermediate resolution result.
940 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
941 /// items are visible in their whole block, while defs only from the place they are defined
943 enum LexicalScopeBinding<'a> {
944 Item(&'a NameBinding<'a>),
948 impl<'a> LexicalScopeBinding<'a> {
949 fn item(self) -> Option<&'a NameBinding<'a>> {
951 LexicalScopeBinding::Item(binding) => Some(binding),
956 fn def(self) -> Def {
958 LexicalScopeBinding::Item(binding) => binding.def(),
959 LexicalScopeBinding::Def(def) => def,
964 #[derive(Copy, Clone, Debug)]
965 pub enum ModuleOrUniformRoot<'a> {
969 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
970 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
971 /// but *not* `extern`), in the Rust 2018 edition.
975 #[derive(Clone, Debug)]
976 enum PathResult<'a> {
977 Module(ModuleOrUniformRoot<'a>),
978 NonModule(PathResolution),
980 Failed(Span, String, bool /* is the error from the last segment? */),
984 /// An anonymous module, eg. just a block.
989 /// { // This is an anonymous module
990 /// f(); // This resolves to (2) as we are inside the block.
993 /// f(); // Resolves to (1)
997 /// Any module with a name.
1001 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1002 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1007 /// One node in the tree of modules.
1008 pub struct ModuleData<'a> {
1009 parent: Option<Module<'a>>,
1012 // The def id of the closest normal module (`mod`) ancestor (including this module).
1013 normal_ancestor_id: DefId,
1015 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1016 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>, Option<Def>)>>,
1017 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1018 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1020 // Macro invocations that can expand into items in this module.
1021 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1023 no_implicit_prelude: bool,
1025 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1026 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1028 // Used to memoize the traits in this module for faster searches through all traits in scope.
1029 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1031 // Whether this module is populated. If not populated, any attempt to
1032 // access the children must be preceded with a
1033 // `populate_module_if_necessary` call.
1034 populated: Cell<bool>,
1036 /// Span of the module itself. Used for error reporting.
1042 type Module<'a> = &'a ModuleData<'a>;
1044 impl<'a> ModuleData<'a> {
1045 fn new(parent: Option<Module<'a>>,
1047 normal_ancestor_id: DefId,
1049 span: Span) -> Self {
1054 resolutions: RefCell::new(FxHashMap()),
1055 legacy_macro_resolutions: RefCell::new(Vec::new()),
1056 macro_resolutions: RefCell::new(Vec::new()),
1057 builtin_attrs: RefCell::new(Vec::new()),
1058 unresolved_invocations: RefCell::new(FxHashSet()),
1059 no_implicit_prelude: false,
1060 glob_importers: RefCell::new(Vec::new()),
1061 globs: RefCell::new(Vec::new()),
1062 traits: RefCell::new(None),
1063 populated: Cell::new(normal_ancestor_id.is_local()),
1069 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1070 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1071 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1075 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1076 let resolutions = self.resolutions.borrow();
1077 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1078 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1079 for &(&(ident, ns), &resolution) in resolutions.iter() {
1080 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1084 fn def(&self) -> Option<Def> {
1086 ModuleKind::Def(def, _) => Some(def),
1091 fn def_id(&self) -> Option<DefId> {
1092 self.def().as_ref().map(Def::def_id)
1095 // `self` resolves to the first module ancestor that `is_normal`.
1096 fn is_normal(&self) -> bool {
1098 ModuleKind::Def(Def::Mod(_), _) => true,
1103 fn is_trait(&self) -> bool {
1105 ModuleKind::Def(Def::Trait(_), _) => true,
1110 fn is_local(&self) -> bool {
1111 self.normal_ancestor_id.is_local()
1114 fn nearest_item_scope(&'a self) -> Module<'a> {
1115 if self.is_trait() { self.parent.unwrap() } else { self }
1119 impl<'a> fmt::Debug for ModuleData<'a> {
1120 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1121 write!(f, "{:?}", self.def())
1125 /// Records a possibly-private value, type, or module definition.
1126 #[derive(Clone, Debug)]
1127 pub struct NameBinding<'a> {
1128 kind: NameBindingKind<'a>,
1131 vis: ty::Visibility,
1134 pub trait ToNameBinding<'a> {
1135 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1138 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1139 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1144 #[derive(Clone, Debug)]
1145 enum NameBindingKind<'a> {
1146 Def(Def, /* is_macro_export */ bool),
1149 binding: &'a NameBinding<'a>,
1150 directive: &'a ImportDirective<'a>,
1154 b1: &'a NameBinding<'a>,
1155 b2: &'a NameBinding<'a>,
1159 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1161 struct UseError<'a> {
1162 err: DiagnosticBuilder<'a>,
1163 /// Attach `use` statements for these candidates
1164 candidates: Vec<ImportSuggestion>,
1165 /// The node id of the module to place the use statements in
1167 /// Whether the diagnostic should state that it's "better"
1171 struct AmbiguityError<'a> {
1173 b1: &'a NameBinding<'a>,
1174 b2: &'a NameBinding<'a>,
1177 impl<'a> NameBinding<'a> {
1178 fn module(&self) -> Option<Module<'a>> {
1180 NameBindingKind::Module(module) => Some(module),
1181 NameBindingKind::Import { binding, .. } => binding.module(),
1186 fn def(&self) -> Def {
1188 NameBindingKind::Def(def, _) => def,
1189 NameBindingKind::Module(module) => module.def().unwrap(),
1190 NameBindingKind::Import { binding, .. } => binding.def(),
1191 NameBindingKind::Ambiguity { .. } => Def::Err,
1195 fn def_ignoring_ambiguity(&self) -> Def {
1197 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1198 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1203 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1204 resolver.get_macro(self.def_ignoring_ambiguity())
1207 // We sometimes need to treat variants as `pub` for backwards compatibility
1208 fn pseudo_vis(&self) -> ty::Visibility {
1209 if self.is_variant() && self.def().def_id().is_local() {
1210 ty::Visibility::Public
1216 fn is_variant(&self) -> bool {
1218 NameBindingKind::Def(Def::Variant(..), _) |
1219 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1224 fn is_extern_crate(&self) -> bool {
1226 NameBindingKind::Import {
1227 directive: &ImportDirective {
1228 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1235 fn is_import(&self) -> bool {
1237 NameBindingKind::Import { .. } => true,
1242 fn is_renamed_extern_crate(&self) -> bool {
1243 if let NameBindingKind::Import { directive, ..} = self.kind {
1244 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1251 fn is_glob_import(&self) -> bool {
1253 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1254 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1259 fn is_importable(&self) -> bool {
1261 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1266 fn is_macro_def(&self) -> bool {
1268 NameBindingKind::Def(Def::Macro(..), _) => true,
1273 fn macro_kind(&self) -> Option<MacroKind> {
1274 match self.def_ignoring_ambiguity() {
1275 Def::Macro(_, kind) => Some(kind),
1276 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1281 fn descr(&self) -> &'static str {
1282 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1285 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1286 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1287 // Then this function returns `true` if `self` may emerge from a macro *after* that
1288 // in some later round and screw up our previously found resolution.
1289 // See more detailed explanation in
1290 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1291 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1292 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1293 // Expansions are partially ordered, so "may appear after" is an inversion of
1294 // "certainly appears before or simultaneously" and includes unordered cases.
1295 let self_parent_expansion = self.expansion;
1296 let other_parent_expansion = binding.expansion;
1297 let certainly_before_other_or_simultaneously =
1298 other_parent_expansion.is_descendant_of(self_parent_expansion);
1299 let certainly_before_invoc_or_simultaneously =
1300 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1301 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1305 /// Interns the names of the primitive types.
1307 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1308 /// special handling, since they have no place of origin.
1309 struct PrimitiveTypeTable {
1310 primitive_types: FxHashMap<Name, PrimTy>,
1313 impl PrimitiveTypeTable {
1314 fn new() -> PrimitiveTypeTable {
1315 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1317 table.intern("bool", Bool);
1318 table.intern("char", Char);
1319 table.intern("f32", Float(FloatTy::F32));
1320 table.intern("f64", Float(FloatTy::F64));
1321 table.intern("isize", Int(IntTy::Isize));
1322 table.intern("i8", Int(IntTy::I8));
1323 table.intern("i16", Int(IntTy::I16));
1324 table.intern("i32", Int(IntTy::I32));
1325 table.intern("i64", Int(IntTy::I64));
1326 table.intern("i128", Int(IntTy::I128));
1327 table.intern("str", Str);
1328 table.intern("usize", Uint(UintTy::Usize));
1329 table.intern("u8", Uint(UintTy::U8));
1330 table.intern("u16", Uint(UintTy::U16));
1331 table.intern("u32", Uint(UintTy::U32));
1332 table.intern("u64", Uint(UintTy::U64));
1333 table.intern("u128", Uint(UintTy::U128));
1337 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1338 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1342 /// The main resolver class.
1344 /// This is the visitor that walks the whole crate.
1345 pub struct Resolver<'a, 'b: 'a> {
1346 session: &'a Session,
1349 pub definitions: Definitions,
1351 graph_root: Module<'a>,
1353 prelude: Option<Module<'a>>,
1354 extern_prelude: FxHashSet<Name>,
1356 /// n.b. This is used only for better diagnostics, not name resolution itself.
1357 has_self: FxHashSet<DefId>,
1359 /// Names of fields of an item `DefId` accessible with dot syntax.
1360 /// Used for hints during error reporting.
1361 field_names: FxHashMap<DefId, Vec<Name>>,
1363 /// All imports known to succeed or fail.
1364 determined_imports: Vec<&'a ImportDirective<'a>>,
1366 /// All non-determined imports.
1367 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1369 /// The module that represents the current item scope.
1370 current_module: Module<'a>,
1372 /// The current set of local scopes for types and values.
1373 /// FIXME #4948: Reuse ribs to avoid allocation.
1374 ribs: PerNS<Vec<Rib<'a>>>,
1376 /// The current set of local scopes, for labels.
1377 label_ribs: Vec<Rib<'a>>,
1379 /// The trait that the current context can refer to.
1380 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1382 /// The current self type if inside an impl (used for better errors).
1383 current_self_type: Option<Ty>,
1385 /// The current self item if inside an ADT (used for better errors).
1386 current_self_item: Option<NodeId>,
1388 /// The idents for the primitive types.
1389 primitive_type_table: PrimitiveTypeTable,
1392 import_map: ImportMap,
1393 pub freevars: FreevarMap,
1394 freevars_seen: NodeMap<NodeMap<usize>>,
1395 pub export_map: ExportMap,
1396 pub trait_map: TraitMap,
1398 /// A map from nodes to anonymous modules.
1399 /// Anonymous modules are pseudo-modules that are implicitly created around items
1400 /// contained within blocks.
1402 /// For example, if we have this:
1410 /// There will be an anonymous module created around `g` with the ID of the
1411 /// entry block for `f`.
1412 block_map: NodeMap<Module<'a>>,
1413 module_map: FxHashMap<DefId, Module<'a>>,
1414 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1416 pub make_glob_map: bool,
1417 /// Maps imports to the names of items actually imported (this actually maps
1418 /// all imports, but only glob imports are actually interesting).
1419 pub glob_map: GlobMap,
1421 used_imports: FxHashSet<(NodeId, Namespace)>,
1422 pub maybe_unused_trait_imports: NodeSet,
1423 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1425 /// A list of labels as of yet unused. Labels will be removed from this map when
1426 /// they are used (in a `break` or `continue` statement)
1427 pub unused_labels: FxHashMap<NodeId, Span>,
1429 /// privacy errors are delayed until the end in order to deduplicate them
1430 privacy_errors: Vec<PrivacyError<'a>>,
1431 /// ambiguity errors are delayed for deduplication
1432 ambiguity_errors: Vec<AmbiguityError<'a>>,
1433 /// `use` injections are delayed for better placement and deduplication
1434 use_injections: Vec<UseError<'a>>,
1435 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1436 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1438 arenas: &'a ResolverArenas<'a>,
1439 dummy_binding: &'a NameBinding<'a>,
1441 crate_loader: &'a mut CrateLoader<'b>,
1442 macro_names: FxHashSet<Ident>,
1443 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1444 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1445 pub all_macros: FxHashMap<Name, Def>,
1446 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1447 macro_defs: FxHashMap<Mark, DefId>,
1448 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1449 pub whitelisted_legacy_custom_derives: Vec<Name>,
1450 pub found_unresolved_macro: bool,
1452 /// List of crate local macros that we need to warn about as being unused.
1453 /// Right now this only includes macro_rules! macros, and macros 2.0.
1454 unused_macros: FxHashSet<DefId>,
1456 /// Maps the `Mark` of an expansion to its containing module or block.
1457 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1459 /// Avoid duplicated errors for "name already defined".
1460 name_already_seen: FxHashMap<Name, Span>,
1462 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1464 /// This table maps struct IDs into struct constructor IDs,
1465 /// it's not used during normal resolution, only for better error reporting.
1466 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1468 /// Only used for better errors on `fn(): fn()`
1469 current_type_ascription: Vec<Span>,
1471 injected_crate: Option<Module<'a>>,
1474 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1475 pub struct ResolverArenas<'a> {
1476 modules: arena::TypedArena<ModuleData<'a>>,
1477 local_modules: RefCell<Vec<Module<'a>>>,
1478 name_bindings: arena::TypedArena<NameBinding<'a>>,
1479 import_directives: arena::TypedArena<ImportDirective<'a>>,
1480 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1481 invocation_data: arena::TypedArena<InvocationData<'a>>,
1482 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1485 impl<'a> ResolverArenas<'a> {
1486 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1487 let module = self.modules.alloc(module);
1488 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1489 self.local_modules.borrow_mut().push(module);
1493 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1494 self.local_modules.borrow()
1496 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1497 self.name_bindings.alloc(name_binding)
1499 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1500 -> &'a ImportDirective {
1501 self.import_directives.alloc(import_directive)
1503 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1504 self.name_resolutions.alloc(Default::default())
1506 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1507 -> &'a InvocationData<'a> {
1508 self.invocation_data.alloc(expansion_data)
1510 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1511 self.legacy_bindings.alloc(binding)
1515 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1516 fn parent(self, id: DefId) -> Option<DefId> {
1518 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1519 _ => self.cstore.def_key(id).parent,
1520 }.map(|index| DefId { index, ..id })
1524 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1525 /// the resolver is no longer needed as all the relevant information is inline.
1526 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1527 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1528 self.resolve_hir_path_cb(path, is_value,
1529 |resolver, span, error| resolve_error(resolver, span, error))
1532 fn resolve_str_path(
1535 crate_root: Option<&str>,
1536 components: &[&str],
1537 args: Option<P<hir::GenericArgs>>,
1540 let mut segments = iter::once(keywords::CrateRoot.ident())
1542 crate_root.into_iter()
1543 .chain(components.iter().cloned())
1544 .map(Ident::from_str)
1545 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1547 if let Some(args) = args {
1548 let ident = segments.last().unwrap().ident;
1549 *segments.last_mut().unwrap() = hir::PathSegment {
1556 let mut path = hir::Path {
1559 segments: segments.into(),
1562 self.resolve_hir_path(&mut path, is_value);
1566 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1567 self.def_map.get(&id).cloned()
1570 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1571 self.import_map.get(&id).cloned().unwrap_or_default()
1574 fn definitions(&mut self) -> &mut Definitions {
1575 &mut self.definitions
1579 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1580 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1581 /// isn't something that can be returned because it can't be made to live that long,
1582 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1583 /// just that an error occurred.
1584 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1585 -> Result<hir::Path, ()> {
1587 let mut errored = false;
1589 let mut path = if path_str.starts_with("::") {
1593 segments: iter::once(keywords::CrateRoot.ident()).chain({
1594 path_str.split("::").skip(1).map(Ident::from_str)
1595 }).map(hir::PathSegment::from_ident).collect(),
1601 segments: path_str.split("::").map(Ident::from_str)
1602 .map(hir::PathSegment::from_ident).collect(),
1605 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1606 if errored || path.def == Def::Err {
1613 /// resolve_hir_path, but takes a callback in case there was an error
1614 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1615 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1617 let namespace = if is_value { ValueNS } else { TypeNS };
1618 let hir::Path { ref segments, span, ref mut def } = *path;
1619 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1620 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1621 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1622 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1623 *def = module.def().unwrap(),
1624 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1625 *def = path_res.base_def(),
1626 PathResult::NonModule(..) => match self.resolve_path(
1634 PathResult::Failed(span, msg, _) => {
1635 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1639 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1640 PathResult::Indeterminate => unreachable!(),
1641 PathResult::Failed(span, msg, _) => {
1642 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1648 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1649 pub fn new(session: &'a Session,
1653 make_glob_map: MakeGlobMap,
1654 crate_loader: &'a mut CrateLoader<'crateloader>,
1655 arenas: &'a ResolverArenas<'a>)
1656 -> Resolver<'a, 'crateloader> {
1657 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1658 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1659 let graph_root = arenas.alloc_module(ModuleData {
1660 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1661 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1663 let mut module_map = FxHashMap();
1664 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1666 let mut definitions = Definitions::new();
1667 DefCollector::new(&mut definitions, Mark::root())
1668 .collect_root(crate_name, session.local_crate_disambiguator());
1670 let mut extern_prelude: FxHashSet<Name> =
1671 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1673 // HACK(eddyb) this ignore the `no_{core,std}` attributes.
1674 // FIXME(eddyb) warn (elsewhere) if core/std is used with `no_{core,std}`.
1675 // if !attr::contains_name(&krate.attrs, "no_core") {
1676 // if !attr::contains_name(&krate.attrs, "no_std") {
1677 extern_prelude.insert(Symbol::intern("core"));
1678 extern_prelude.insert(Symbol::intern("std"));
1679 extern_prelude.insert(Symbol::intern("meta"));
1681 let mut invocations = FxHashMap();
1682 invocations.insert(Mark::root(),
1683 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1685 let mut macro_defs = FxHashMap();
1686 macro_defs.insert(Mark::root(), root_def_id);
1695 // The outermost module has def ID 0; this is not reflected in the
1701 has_self: FxHashSet(),
1702 field_names: FxHashMap(),
1704 determined_imports: Vec::new(),
1705 indeterminate_imports: Vec::new(),
1707 current_module: graph_root,
1709 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1710 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1711 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1713 label_ribs: Vec::new(),
1715 current_trait_ref: None,
1716 current_self_type: None,
1717 current_self_item: None,
1719 primitive_type_table: PrimitiveTypeTable::new(),
1722 import_map: NodeMap(),
1723 freevars: NodeMap(),
1724 freevars_seen: NodeMap(),
1725 export_map: FxHashMap(),
1726 trait_map: NodeMap(),
1728 block_map: NodeMap(),
1729 extern_module_map: FxHashMap(),
1731 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1732 glob_map: NodeMap(),
1734 used_imports: FxHashSet(),
1735 maybe_unused_trait_imports: NodeSet(),
1736 maybe_unused_extern_crates: Vec::new(),
1738 unused_labels: FxHashMap(),
1740 privacy_errors: Vec::new(),
1741 ambiguity_errors: Vec::new(),
1742 use_injections: Vec::new(),
1743 macro_expanded_macro_export_errors: BTreeSet::new(),
1746 dummy_binding: arenas.alloc_name_binding(NameBinding {
1747 kind: NameBindingKind::Def(Def::Err, false),
1748 expansion: Mark::root(),
1750 vis: ty::Visibility::Public,
1754 macro_names: FxHashSet(),
1755 builtin_macros: FxHashMap(),
1756 macro_use_prelude: FxHashMap(),
1757 all_macros: FxHashMap(),
1758 macro_map: FxHashMap(),
1761 local_macro_def_scopes: FxHashMap(),
1762 name_already_seen: FxHashMap(),
1763 whitelisted_legacy_custom_derives: Vec::new(),
1764 potentially_unused_imports: Vec::new(),
1765 struct_constructors: DefIdMap(),
1766 found_unresolved_macro: false,
1767 unused_macros: FxHashSet(),
1768 current_type_ascription: Vec::new(),
1769 injected_crate: None,
1773 pub fn arenas() -> ResolverArenas<'a> {
1775 modules: arena::TypedArena::new(),
1776 local_modules: RefCell::new(Vec::new()),
1777 name_bindings: arena::TypedArena::new(),
1778 import_directives: arena::TypedArena::new(),
1779 name_resolutions: arena::TypedArena::new(),
1780 invocation_data: arena::TypedArena::new(),
1781 legacy_bindings: arena::TypedArena::new(),
1785 /// Runs the function on each namespace.
1786 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1792 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1794 match self.macro_defs.get(&ctxt.outer()) {
1795 Some(&def_id) => return def_id,
1796 None => ctxt.remove_mark(),
1801 /// Entry point to crate resolution.
1802 pub fn resolve_crate(&mut self, krate: &Crate) {
1803 ImportResolver { resolver: self }.finalize_imports();
1804 self.current_module = self.graph_root;
1805 self.finalize_current_module_macro_resolutions();
1807 visit::walk_crate(self, krate);
1809 check_unused::check_crate(self, krate);
1810 self.report_errors(krate);
1811 self.crate_loader.postprocess(krate);
1818 normal_ancestor_id: DefId,
1822 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1823 self.arenas.alloc_module(module)
1826 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1827 -> bool /* true if an error was reported */ {
1828 match binding.kind {
1829 NameBindingKind::Import { directive, binding, ref used }
1832 directive.used.set(true);
1833 self.used_imports.insert((directive.id, ns));
1834 self.add_to_glob_map(directive.id, ident);
1835 self.record_use(ident, ns, binding)
1837 NameBindingKind::Import { .. } => false,
1838 NameBindingKind::Ambiguity { b1, b2 } => {
1839 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1846 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1847 if self.make_glob_map {
1848 self.glob_map.entry(id).or_default().insert(ident.name);
1852 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1853 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1854 /// `ident` in the first scope that defines it (or None if no scopes define it).
1856 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1857 /// the items are defined in the block. For example,
1860 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1863 /// g(); // This resolves to the local variable `g` since it shadows the item.
1867 /// Invariant: This must only be called during main resolution, not during
1868 /// import resolution.
1869 fn resolve_ident_in_lexical_scope(&mut self,
1872 record_used_id: Option<NodeId>,
1874 -> Option<LexicalScopeBinding<'a>> {
1875 let record_used = record_used_id.is_some();
1876 assert!(ns == TypeNS || ns == ValueNS);
1878 ident.span = if ident.name == keywords::SelfType.name() {
1879 // FIXME(jseyfried) improve `Self` hygiene
1880 ident.span.with_ctxt(SyntaxContext::empty())
1885 ident = ident.modern_and_legacy();
1888 // Walk backwards up the ribs in scope.
1889 let mut module = self.graph_root;
1890 for i in (0 .. self.ribs[ns].len()).rev() {
1891 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1892 // The ident resolves to a type parameter or local variable.
1893 return Some(LexicalScopeBinding::Def(
1894 self.adjust_local_def(ns, i, def, record_used, path_span)
1898 module = match self.ribs[ns][i].kind {
1899 ModuleRibKind(module) => module,
1900 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1901 // If an invocation of this macro created `ident`, give up on `ident`
1902 // and switch to `ident`'s source from the macro definition.
1903 ident.span.remove_mark();
1909 let item = self.resolve_ident_in_module_unadjusted(
1910 ModuleOrUniformRoot::Module(module),
1917 if let Ok(binding) = item {
1918 // The ident resolves to an item.
1919 return Some(LexicalScopeBinding::Item(binding));
1923 ModuleKind::Block(..) => {}, // We can see through blocks
1928 ident.span = ident.span.modern();
1929 let mut poisoned = None;
1931 let opt_module = if let Some(node_id) = record_used_id {
1932 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1933 node_id, &mut poisoned)
1935 self.hygienic_lexical_parent(module, &mut ident.span)
1937 module = unwrap_or!(opt_module, break);
1938 let orig_current_module = self.current_module;
1939 self.current_module = module; // Lexical resolutions can never be a privacy error.
1940 let result = self.resolve_ident_in_module_unadjusted(
1941 ModuleOrUniformRoot::Module(module),
1948 self.current_module = orig_current_module;
1952 if let Some(node_id) = poisoned {
1953 self.session.buffer_lint_with_diagnostic(
1954 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1955 node_id, ident.span,
1956 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1957 lint::builtin::BuiltinLintDiagnostics::
1958 ProcMacroDeriveResolutionFallback(ident.span),
1961 return Some(LexicalScopeBinding::Item(binding))
1963 Err(Determined) => continue,
1964 Err(Undetermined) =>
1965 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1969 if !module.no_implicit_prelude {
1970 // `record_used` means that we don't try to load crates during speculative resolution
1971 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1972 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1973 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1974 self.populate_module_if_necessary(&crate_root);
1976 let binding = (crate_root, ty::Visibility::Public,
1977 ident.span, Mark::root()).to_name_binding(self.arenas);
1978 return Some(LexicalScopeBinding::Item(binding));
1980 if ns == TypeNS && is_known_tool(ident.name) {
1981 let binding = (Def::ToolMod, ty::Visibility::Public,
1982 ident.span, Mark::root()).to_name_binding(self.arenas);
1983 return Some(LexicalScopeBinding::Item(binding));
1985 if let Some(prelude) = self.prelude {
1986 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1987 ModuleOrUniformRoot::Module(prelude),
1994 return Some(LexicalScopeBinding::Item(binding));
2002 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2003 -> Option<Module<'a>> {
2004 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2005 return Some(self.macro_def_scope(span.remove_mark()));
2008 if let ModuleKind::Block(..) = module.kind {
2009 return Some(module.parent.unwrap());
2015 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2016 span: &mut Span, node_id: NodeId,
2017 poisoned: &mut Option<NodeId>)
2018 -> Option<Module<'a>> {
2019 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2023 // We need to support the next case under a deprecation warning
2026 // ---- begin: this comes from a proc macro derive
2027 // mod implementation_details {
2028 // // Note that `MyStruct` is not in scope here.
2029 // impl SomeTrait for MyStruct { ... }
2033 // So we have to fall back to the module's parent during lexical resolution in this case.
2034 if let Some(parent) = module.parent {
2035 // Inner module is inside the macro, parent module is outside of the macro.
2036 if module.expansion != parent.expansion &&
2037 module.expansion.is_descendant_of(parent.expansion) {
2038 // The macro is a proc macro derive
2039 if module.expansion.looks_like_proc_macro_derive() {
2040 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2041 *poisoned = Some(node_id);
2042 return module.parent;
2051 fn resolve_ident_in_module(&mut self,
2052 module: ModuleOrUniformRoot<'a>,
2057 -> Result<&'a NameBinding<'a>, Determinacy> {
2058 ident.span = ident.span.modern();
2059 let orig_current_module = self.current_module;
2060 if let ModuleOrUniformRoot::Module(module) = module {
2061 if let Some(def) = ident.span.adjust(module.expansion) {
2062 self.current_module = self.macro_def_scope(def);
2065 let result = self.resolve_ident_in_module_unadjusted(
2066 module, ident, ns, false, record_used, span,
2068 self.current_module = orig_current_module;
2072 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2073 let mut ctxt = ident.span.ctxt();
2074 let mark = if ident.name == keywords::DollarCrate.name() {
2075 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2076 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2077 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2078 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2079 // definitions actually produced by `macro` and `macro` definitions produced by
2080 // `macro_rules!`, but at least such configurations are not stable yet.
2081 ctxt = ctxt.modern_and_legacy();
2082 let mut iter = ctxt.marks().into_iter().rev().peekable();
2083 let mut result = None;
2084 // Find the last modern mark from the end if it exists.
2085 while let Some(&(mark, transparency)) = iter.peek() {
2086 if transparency == Transparency::Opaque {
2087 result = Some(mark);
2093 // Then find the last legacy mark from the end if it exists.
2094 for (mark, transparency) in iter {
2095 if transparency == Transparency::SemiTransparent {
2096 result = Some(mark);
2103 ctxt = ctxt.modern();
2104 ctxt.adjust(Mark::root())
2106 let module = match mark {
2107 Some(def) => self.macro_def_scope(def),
2108 None => return self.graph_root,
2110 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2113 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2114 let mut module = self.get_module(module.normal_ancestor_id);
2115 while module.span.ctxt().modern() != *ctxt {
2116 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2117 module = self.get_module(parent.normal_ancestor_id);
2124 // We maintain a list of value ribs and type ribs.
2126 // Simultaneously, we keep track of the current position in the module
2127 // graph in the `current_module` pointer. When we go to resolve a name in
2128 // the value or type namespaces, we first look through all the ribs and
2129 // then query the module graph. When we resolve a name in the module
2130 // namespace, we can skip all the ribs (since nested modules are not
2131 // allowed within blocks in Rust) and jump straight to the current module
2134 // Named implementations are handled separately. When we find a method
2135 // call, we consult the module node to find all of the implementations in
2136 // scope. This information is lazily cached in the module node. We then
2137 // generate a fake "implementation scope" containing all the
2138 // implementations thus found, for compatibility with old resolve pass.
2140 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2141 where F: FnOnce(&mut Resolver) -> T
2143 let id = self.definitions.local_def_id(id);
2144 let module = self.module_map.get(&id).cloned(); // clones a reference
2145 if let Some(module) = module {
2146 // Move down in the graph.
2147 let orig_module = replace(&mut self.current_module, module);
2148 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2149 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2151 self.finalize_current_module_macro_resolutions();
2154 self.current_module = orig_module;
2155 self.ribs[ValueNS].pop();
2156 self.ribs[TypeNS].pop();
2163 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2164 /// is returned by the given predicate function
2166 /// Stops after meeting a closure.
2167 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2168 where P: Fn(&Rib, Ident) -> Option<R>
2170 for rib in self.label_ribs.iter().rev() {
2173 // If an invocation of this macro created `ident`, give up on `ident`
2174 // and switch to `ident`'s source from the macro definition.
2175 MacroDefinition(def) => {
2176 if def == self.macro_def(ident.span.ctxt()) {
2177 ident.span.remove_mark();
2181 // Do not resolve labels across function boundary
2185 let r = pred(rib, ident);
2193 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2194 self.with_current_self_item(item, |this| {
2195 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2196 let item_def_id = this.definitions.local_def_id(item.id);
2197 if this.session.features_untracked().self_in_typedefs {
2198 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2199 visit::walk_item(this, item);
2202 visit::walk_item(this, item);
2208 fn resolve_item(&mut self, item: &Item) {
2209 let name = item.ident.name;
2210 debug!("(resolving item) resolving {}", name);
2213 ItemKind::Ty(_, ref generics) |
2214 ItemKind::Fn(_, _, ref generics, _) |
2215 ItemKind::Existential(_, ref generics) => {
2216 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2217 |this| visit::walk_item(this, item));
2220 ItemKind::Enum(_, ref generics) |
2221 ItemKind::Struct(_, ref generics) |
2222 ItemKind::Union(_, ref generics) => {
2223 self.resolve_adt(item, generics);
2226 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2227 self.resolve_implementation(generics,
2233 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2234 // Create a new rib for the trait-wide type parameters.
2235 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2236 let local_def_id = this.definitions.local_def_id(item.id);
2237 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2238 this.visit_generics(generics);
2239 walk_list!(this, visit_param_bound, bounds);
2241 for trait_item in trait_items {
2242 let type_parameters = HasTypeParameters(&trait_item.generics,
2243 TraitOrImplItemRibKind);
2244 this.with_type_parameter_rib(type_parameters, |this| {
2245 match trait_item.node {
2246 TraitItemKind::Const(ref ty, ref default) => {
2249 // Only impose the restrictions of
2250 // ConstRibKind for an actual constant
2251 // expression in a provided default.
2252 if let Some(ref expr) = *default{
2253 this.with_constant_rib(|this| {
2254 this.visit_expr(expr);
2258 TraitItemKind::Method(_, _) => {
2259 visit::walk_trait_item(this, trait_item)
2261 TraitItemKind::Type(..) => {
2262 visit::walk_trait_item(this, trait_item)
2264 TraitItemKind::Macro(_) => {
2265 panic!("unexpanded macro in resolve!")
2274 ItemKind::TraitAlias(ref generics, ref bounds) => {
2275 // Create a new rib for the trait-wide type parameters.
2276 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2277 let local_def_id = this.definitions.local_def_id(item.id);
2278 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2279 this.visit_generics(generics);
2280 walk_list!(this, visit_param_bound, bounds);
2285 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2286 self.with_scope(item.id, |this| {
2287 visit::walk_item(this, item);
2291 ItemKind::Static(ref ty, _, ref expr) |
2292 ItemKind::Const(ref ty, ref expr) => {
2293 self.with_item_rib(|this| {
2295 this.with_constant_rib(|this| {
2296 this.visit_expr(expr);
2301 ItemKind::Use(ref use_tree) => {
2302 // Imports are resolved as global by default, add starting root segment.
2304 segments: use_tree.prefix.make_root().into_iter().collect(),
2305 span: use_tree.span,
2307 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2310 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2311 // do nothing, these are just around to be encoded
2314 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2318 /// For the most part, use trees are desugared into `ImportDirective` instances
2319 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2320 /// there is one special case we handle here: an empty nested import like
2321 /// `a::{b::{}}`, which desugares into...no import directives.
2322 fn resolve_use_tree(
2327 use_tree: &ast::UseTree,
2330 match use_tree.kind {
2331 ast::UseTreeKind::Nested(ref items) => {
2333 segments: prefix.segments
2335 .chain(use_tree.prefix.segments.iter())
2338 span: prefix.span.to(use_tree.prefix.span),
2341 if items.len() == 0 {
2342 // Resolve prefix of an import with empty braces (issue #28388).
2343 self.smart_resolve_path_with_crate_lint(
2347 PathSource::ImportPrefix,
2348 CrateLint::UsePath { root_id, root_span },
2351 for &(ref tree, nested_id) in items {
2352 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2356 ast::UseTreeKind::Simple(..) => {},
2357 ast::UseTreeKind::Glob => {},
2361 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2362 where F: FnOnce(&mut Resolver)
2364 match type_parameters {
2365 HasTypeParameters(generics, rib_kind) => {
2366 let mut function_type_rib = Rib::new(rib_kind);
2367 let mut seen_bindings = FxHashMap();
2368 for param in &generics.params {
2370 GenericParamKind::Lifetime { .. } => {}
2371 GenericParamKind::Type { .. } => {
2372 let ident = param.ident.modern();
2373 debug!("with_type_parameter_rib: {}", param.id);
2375 if seen_bindings.contains_key(&ident) {
2376 let span = seen_bindings.get(&ident).unwrap();
2377 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2381 resolve_error(self, param.ident.span, err);
2383 seen_bindings.entry(ident).or_insert(param.ident.span);
2385 // Plain insert (no renaming).
2386 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2387 function_type_rib.bindings.insert(ident, def);
2388 self.record_def(param.id, PathResolution::new(def));
2392 self.ribs[TypeNS].push(function_type_rib);
2395 NoTypeParameters => {
2402 if let HasTypeParameters(..) = type_parameters {
2403 self.ribs[TypeNS].pop();
2407 fn with_label_rib<F>(&mut self, f: F)
2408 where F: FnOnce(&mut Resolver)
2410 self.label_ribs.push(Rib::new(NormalRibKind));
2412 self.label_ribs.pop();
2415 fn with_item_rib<F>(&mut self, f: F)
2416 where F: FnOnce(&mut Resolver)
2418 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2419 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2421 self.ribs[TypeNS].pop();
2422 self.ribs[ValueNS].pop();
2425 fn with_constant_rib<F>(&mut self, f: F)
2426 where F: FnOnce(&mut Resolver)
2428 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2429 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2431 self.label_ribs.pop();
2432 self.ribs[ValueNS].pop();
2435 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2436 where F: FnOnce(&mut Resolver) -> T
2438 // Handle nested impls (inside fn bodies)
2439 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2440 let result = f(self);
2441 self.current_self_type = previous_value;
2445 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2446 where F: FnOnce(&mut Resolver) -> T
2448 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2449 let result = f(self);
2450 self.current_self_item = previous_value;
2454 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2455 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2456 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2458 let mut new_val = None;
2459 let mut new_id = None;
2460 if let Some(trait_ref) = opt_trait_ref {
2461 let path: Vec<_> = trait_ref.path.segments.iter()
2462 .map(|seg| seg.ident)
2464 let def = self.smart_resolve_path_fragment(
2468 trait_ref.path.span,
2469 PathSource::Trait(AliasPossibility::No),
2470 CrateLint::SimplePath(trait_ref.ref_id),
2472 if def != Def::Err {
2473 new_id = Some(def.def_id());
2474 let span = trait_ref.path.span;
2475 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2482 CrateLint::SimplePath(trait_ref.ref_id),
2485 new_val = Some((module, trait_ref.clone()));
2489 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2490 let result = f(self, new_id);
2491 self.current_trait_ref = original_trait_ref;
2495 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2496 where F: FnOnce(&mut Resolver)
2498 let mut self_type_rib = Rib::new(NormalRibKind);
2500 // plain insert (no renaming, types are not currently hygienic....)
2501 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2502 self.ribs[TypeNS].push(self_type_rib);
2504 self.ribs[TypeNS].pop();
2507 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2508 where F: FnOnce(&mut Resolver)
2510 let self_def = Def::SelfCtor(impl_id);
2511 let mut self_type_rib = Rib::new(NormalRibKind);
2512 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2513 self.ribs[ValueNS].push(self_type_rib);
2515 self.ribs[ValueNS].pop();
2518 fn resolve_implementation(&mut self,
2519 generics: &Generics,
2520 opt_trait_reference: &Option<TraitRef>,
2523 impl_items: &[ImplItem]) {
2524 // If applicable, create a rib for the type parameters.
2525 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2526 // Dummy self type for better errors if `Self` is used in the trait path.
2527 this.with_self_rib(Def::SelfTy(None, None), |this| {
2528 // Resolve the trait reference, if necessary.
2529 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2530 let item_def_id = this.definitions.local_def_id(item_id);
2531 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2532 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2533 // Resolve type arguments in the trait path.
2534 visit::walk_trait_ref(this, trait_ref);
2536 // Resolve the self type.
2537 this.visit_ty(self_type);
2538 // Resolve the type parameters.
2539 this.visit_generics(generics);
2540 // Resolve the items within the impl.
2541 this.with_current_self_type(self_type, |this| {
2542 this.with_self_struct_ctor_rib(item_def_id, |this| {
2543 for impl_item in impl_items {
2544 this.resolve_visibility(&impl_item.vis);
2546 // We also need a new scope for the impl item type parameters.
2547 let type_parameters = HasTypeParameters(&impl_item.generics,
2548 TraitOrImplItemRibKind);
2549 this.with_type_parameter_rib(type_parameters, |this| {
2550 use self::ResolutionError::*;
2551 match impl_item.node {
2552 ImplItemKind::Const(..) => {
2553 // If this is a trait impl, ensure the const
2555 this.check_trait_item(impl_item.ident,
2558 |n, s| ConstNotMemberOfTrait(n, s));
2559 this.with_constant_rib(|this|
2560 visit::walk_impl_item(this, impl_item)
2563 ImplItemKind::Method(..) => {
2564 // If this is a trait impl, ensure the method
2566 this.check_trait_item(impl_item.ident,
2569 |n, s| MethodNotMemberOfTrait(n, s));
2571 visit::walk_impl_item(this, impl_item);
2573 ImplItemKind::Type(ref ty) => {
2574 // If this is a trait impl, ensure the type
2576 this.check_trait_item(impl_item.ident,
2579 |n, s| TypeNotMemberOfTrait(n, s));
2583 ImplItemKind::Existential(ref bounds) => {
2584 // If this is a trait impl, ensure the type
2586 this.check_trait_item(impl_item.ident,
2589 |n, s| TypeNotMemberOfTrait(n, s));
2591 for bound in bounds {
2592 this.visit_param_bound(bound);
2595 ImplItemKind::Macro(_) =>
2596 panic!("unexpanded macro in resolve!"),
2608 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2609 where F: FnOnce(Name, &str) -> ResolutionError
2611 // If there is a TraitRef in scope for an impl, then the method must be in the
2613 if let Some((module, _)) = self.current_trait_ref {
2614 if self.resolve_ident_in_module(
2615 ModuleOrUniformRoot::Module(module),
2621 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2622 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2627 fn resolve_local(&mut self, local: &Local) {
2628 // Resolve the type.
2629 walk_list!(self, visit_ty, &local.ty);
2631 // Resolve the initializer.
2632 walk_list!(self, visit_expr, &local.init);
2634 // Resolve the pattern.
2635 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2638 // build a map from pattern identifiers to binding-info's.
2639 // this is done hygienically. This could arise for a macro
2640 // that expands into an or-pattern where one 'x' was from the
2641 // user and one 'x' came from the macro.
2642 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2643 let mut binding_map = FxHashMap();
2645 pat.walk(&mut |pat| {
2646 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2647 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2648 Some(Def::Local(..)) => true,
2651 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2652 binding_map.insert(ident, binding_info);
2661 // check that all of the arms in an or-pattern have exactly the
2662 // same set of bindings, with the same binding modes for each.
2663 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2664 if pats.is_empty() {
2668 let mut missing_vars = FxHashMap();
2669 let mut inconsistent_vars = FxHashMap();
2670 for (i, p) in pats.iter().enumerate() {
2671 let map_i = self.binding_mode_map(&p);
2673 for (j, q) in pats.iter().enumerate() {
2678 let map_j = self.binding_mode_map(&q);
2679 for (&key, &binding_i) in &map_i {
2680 if map_j.len() == 0 { // Account for missing bindings when
2681 let binding_error = missing_vars // map_j has none.
2683 .or_insert(BindingError {
2685 origin: BTreeSet::new(),
2686 target: BTreeSet::new(),
2688 binding_error.origin.insert(binding_i.span);
2689 binding_error.target.insert(q.span);
2691 for (&key_j, &binding_j) in &map_j {
2692 match map_i.get(&key_j) {
2693 None => { // missing binding
2694 let binding_error = missing_vars
2696 .or_insert(BindingError {
2698 origin: BTreeSet::new(),
2699 target: BTreeSet::new(),
2701 binding_error.origin.insert(binding_j.span);
2702 binding_error.target.insert(p.span);
2704 Some(binding_i) => { // check consistent binding
2705 if binding_i.binding_mode != binding_j.binding_mode {
2708 .or_insert((binding_j.span, binding_i.span));
2716 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2717 missing_vars.sort();
2718 for (_, v) in missing_vars {
2720 *v.origin.iter().next().unwrap(),
2721 ResolutionError::VariableNotBoundInPattern(v));
2723 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2724 inconsistent_vars.sort();
2725 for (name, v) in inconsistent_vars {
2726 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2730 fn resolve_arm(&mut self, arm: &Arm) {
2731 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2733 let mut bindings_list = FxHashMap();
2734 for pattern in &arm.pats {
2735 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2738 // This has to happen *after* we determine which pat_idents are variants
2739 self.check_consistent_bindings(&arm.pats);
2742 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2745 self.visit_expr(&arm.body);
2747 self.ribs[ValueNS].pop();
2750 fn resolve_block(&mut self, block: &Block) {
2751 debug!("(resolving block) entering block");
2752 // Move down in the graph, if there's an anonymous module rooted here.
2753 let orig_module = self.current_module;
2754 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2756 let mut num_macro_definition_ribs = 0;
2757 if let Some(anonymous_module) = anonymous_module {
2758 debug!("(resolving block) found anonymous module, moving down");
2759 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2760 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2761 self.current_module = anonymous_module;
2762 self.finalize_current_module_macro_resolutions();
2764 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2767 // Descend into the block.
2768 for stmt in &block.stmts {
2769 if let ast::StmtKind::Item(ref item) = stmt.node {
2770 if let ast::ItemKind::MacroDef(..) = item.node {
2771 num_macro_definition_ribs += 1;
2772 let def = self.definitions.local_def_id(item.id);
2773 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2774 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2778 self.visit_stmt(stmt);
2782 self.current_module = orig_module;
2783 for _ in 0 .. num_macro_definition_ribs {
2784 self.ribs[ValueNS].pop();
2785 self.label_ribs.pop();
2787 self.ribs[ValueNS].pop();
2788 if anonymous_module.is_some() {
2789 self.ribs[TypeNS].pop();
2791 debug!("(resolving block) leaving block");
2794 fn fresh_binding(&mut self,
2797 outer_pat_id: NodeId,
2798 pat_src: PatternSource,
2799 bindings: &mut FxHashMap<Ident, NodeId>)
2801 // Add the binding to the local ribs, if it
2802 // doesn't already exist in the bindings map. (We
2803 // must not add it if it's in the bindings map
2804 // because that breaks the assumptions later
2805 // passes make about or-patterns.)
2806 let ident = ident.modern_and_legacy();
2807 let mut def = Def::Local(pat_id);
2808 match bindings.get(&ident).cloned() {
2809 Some(id) if id == outer_pat_id => {
2810 // `Variant(a, a)`, error
2814 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2818 Some(..) if pat_src == PatternSource::FnParam => {
2819 // `fn f(a: u8, a: u8)`, error
2823 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2827 Some(..) if pat_src == PatternSource::Match ||
2828 pat_src == PatternSource::IfLet ||
2829 pat_src == PatternSource::WhileLet => {
2830 // `Variant1(a) | Variant2(a)`, ok
2831 // Reuse definition from the first `a`.
2832 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2835 span_bug!(ident.span, "two bindings with the same name from \
2836 unexpected pattern source {:?}", pat_src);
2839 // A completely fresh binding, add to the lists if it's valid.
2840 if ident.name != keywords::Invalid.name() {
2841 bindings.insert(ident, outer_pat_id);
2842 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2847 PathResolution::new(def)
2850 fn resolve_pattern(&mut self,
2852 pat_src: PatternSource,
2853 // Maps idents to the node ID for the
2854 // outermost pattern that binds them.
2855 bindings: &mut FxHashMap<Ident, NodeId>) {
2856 // Visit all direct subpatterns of this pattern.
2857 let outer_pat_id = pat.id;
2858 pat.walk(&mut |pat| {
2860 PatKind::Ident(bmode, ident, ref opt_pat) => {
2861 // First try to resolve the identifier as some existing
2862 // entity, then fall back to a fresh binding.
2863 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2865 .and_then(LexicalScopeBinding::item);
2866 let resolution = binding.map(NameBinding::def).and_then(|def| {
2867 let is_syntactic_ambiguity = opt_pat.is_none() &&
2868 bmode == BindingMode::ByValue(Mutability::Immutable);
2870 Def::StructCtor(_, CtorKind::Const) |
2871 Def::VariantCtor(_, CtorKind::Const) |
2872 Def::Const(..) if is_syntactic_ambiguity => {
2873 // Disambiguate in favor of a unit struct/variant
2874 // or constant pattern.
2875 self.record_use(ident, ValueNS, binding.unwrap());
2876 Some(PathResolution::new(def))
2878 Def::StructCtor(..) | Def::VariantCtor(..) |
2879 Def::Const(..) | Def::Static(..) => {
2880 // This is unambiguously a fresh binding, either syntactically
2881 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2882 // to something unusable as a pattern (e.g. constructor function),
2883 // but we still conservatively report an error, see
2884 // issues/33118#issuecomment-233962221 for one reason why.
2888 ResolutionError::BindingShadowsSomethingUnacceptable(
2889 pat_src.descr(), ident.name, binding.unwrap())
2893 Def::Fn(..) | Def::Err => {
2894 // These entities are explicitly allowed
2895 // to be shadowed by fresh bindings.
2899 span_bug!(ident.span, "unexpected definition for an \
2900 identifier in pattern: {:?}", def);
2903 }).unwrap_or_else(|| {
2904 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2907 self.record_def(pat.id, resolution);
2910 PatKind::TupleStruct(ref path, ..) => {
2911 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2914 PatKind::Path(ref qself, ref path) => {
2915 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2918 PatKind::Struct(ref path, ..) => {
2919 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2927 visit::walk_pat(self, pat);
2930 // High-level and context dependent path resolution routine.
2931 // Resolves the path and records the resolution into definition map.
2932 // If resolution fails tries several techniques to find likely
2933 // resolution candidates, suggest imports or other help, and report
2934 // errors in user friendly way.
2935 fn smart_resolve_path(&mut self,
2937 qself: Option<&QSelf>,
2941 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2944 /// A variant of `smart_resolve_path` where you also specify extra
2945 /// information about where the path came from; this extra info is
2946 /// sometimes needed for the lint that recommends rewriting
2947 /// absolute paths to `crate`, so that it knows how to frame the
2948 /// suggestion. If you are just resolving a path like `foo::bar`
2949 /// that appears...somewhere, though, then you just want
2950 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2951 /// already provides.
2952 fn smart_resolve_path_with_crate_lint(
2955 qself: Option<&QSelf>,
2958 crate_lint: CrateLint
2959 ) -> PathResolution {
2960 let segments = &path.segments.iter()
2961 .map(|seg| seg.ident)
2962 .collect::<Vec<_>>();
2963 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2966 fn smart_resolve_path_fragment(&mut self,
2968 qself: Option<&QSelf>,
2972 crate_lint: CrateLint)
2974 let ident_span = path.last().map_or(span, |ident| ident.span);
2975 let ns = source.namespace();
2976 let is_expected = &|def| source.is_expected(def);
2977 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2979 // Base error is amended with one short label and possibly some longer helps/notes.
2980 let report_errors = |this: &mut Self, def: Option<Def>| {
2981 // Make the base error.
2982 let expected = source.descr_expected();
2983 let path_str = names_to_string(path);
2984 let code = source.error_code(def.is_some());
2985 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2986 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2987 format!("not a {}", expected),
2990 let item_str = path[path.len() - 1];
2991 let item_span = path[path.len() - 1].span;
2992 let (mod_prefix, mod_str) = if path.len() == 1 {
2993 (String::new(), "this scope".to_string())
2994 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2995 (String::new(), "the crate root".to_string())
2997 let mod_path = &path[..path.len() - 1];
2998 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2999 false, span, CrateLint::No) {
3000 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3003 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3004 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
3006 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3007 format!("not found in {}", mod_str),
3010 let code = DiagnosticId::Error(code.into());
3011 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3013 // Emit special messages for unresolved `Self` and `self`.
3014 if is_self_type(path, ns) {
3015 __diagnostic_used!(E0411);
3016 err.code(DiagnosticId::Error("E0411".into()));
3017 let available_in = if this.session.features_untracked().self_in_typedefs {
3018 "impls, traits, and type definitions"
3022 err.span_label(span, format!("`Self` is only available in {}", available_in));
3023 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3024 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3027 return (err, Vec::new());
3029 if is_self_value(path, ns) {
3030 __diagnostic_used!(E0424);
3031 err.code(DiagnosticId::Error("E0424".into()));
3032 err.span_label(span, format!("`self` value is a keyword \
3034 methods with `self` parameter"));
3035 return (err, Vec::new());
3038 // Try to lookup the name in more relaxed fashion for better error reporting.
3039 let ident = *path.last().unwrap();
3040 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3041 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3042 let enum_candidates =
3043 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3044 let mut enum_candidates = enum_candidates.iter()
3045 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3046 enum_candidates.sort();
3047 for (sp, variant_path, enum_path) in enum_candidates {
3049 let msg = format!("there is an enum variant `{}`, \
3055 err.span_suggestion_with_applicability(
3057 "you can try using the variant's enum",
3059 Applicability::MachineApplicable,
3064 if path.len() == 1 && this.self_type_is_available(span) {
3065 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3066 let self_is_available = this.self_value_is_available(path[0].span, span);
3068 AssocSuggestion::Field => {
3069 err.span_suggestion_with_applicability(
3072 format!("self.{}", path_str),
3073 Applicability::MachineApplicable,
3075 if !self_is_available {
3076 err.span_label(span, format!("`self` value is a keyword \
3078 methods with `self` parameter"));
3081 AssocSuggestion::MethodWithSelf if self_is_available => {
3082 err.span_suggestion_with_applicability(
3085 format!("self.{}", path_str),
3086 Applicability::MachineApplicable,
3089 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3090 err.span_suggestion_with_applicability(
3093 format!("Self::{}", path_str),
3094 Applicability::MachineApplicable,
3098 return (err, candidates);
3102 let mut levenshtein_worked = false;
3105 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3106 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3107 levenshtein_worked = true;
3110 // Try context dependent help if relaxed lookup didn't work.
3111 if let Some(def) = def {
3112 match (def, source) {
3113 (Def::Macro(..), _) => {
3114 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3115 return (err, candidates);
3117 (Def::TyAlias(..), PathSource::Trait(_)) => {
3118 err.span_label(span, "type aliases cannot be used for traits");
3119 return (err, candidates);
3121 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3122 ExprKind::Field(_, ident) => {
3123 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3125 return (err, candidates);
3127 ExprKind::MethodCall(ref segment, ..) => {
3128 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3129 path_str, segment.ident));
3130 return (err, candidates);
3134 (Def::Enum(..), PathSource::TupleStruct)
3135 | (Def::Enum(..), PathSource::Expr(..)) => {
3136 if let Some(variants) = this.collect_enum_variants(def) {
3137 err.note(&format!("did you mean to use one \
3138 of the following variants?\n{}",
3140 .map(|suggestion| path_names_to_string(suggestion))
3141 .map(|suggestion| format!("- `{}`", suggestion))
3142 .collect::<Vec<_>>()
3146 err.note("did you mean to use one of the enum's variants?");
3148 return (err, candidates);
3150 (Def::Struct(def_id), _) if ns == ValueNS => {
3151 if let Some((ctor_def, ctor_vis))
3152 = this.struct_constructors.get(&def_id).cloned() {
3153 let accessible_ctor = this.is_accessible(ctor_vis);
3154 if is_expected(ctor_def) && !accessible_ctor {
3155 err.span_label(span, format!("constructor is not visible \
3156 here due to private fields"));
3159 // HACK(estebank): find a better way to figure out that this was a
3160 // parser issue where a struct literal is being used on an expression
3161 // where a brace being opened means a block is being started. Look
3162 // ahead for the next text to see if `span` is followed by a `{`.
3163 let cm = this.session.source_map();
3166 sp = cm.next_point(sp);
3167 match cm.span_to_snippet(sp) {
3168 Ok(ref snippet) => {
3169 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3176 let followed_by_brace = match cm.span_to_snippet(sp) {
3177 Ok(ref snippet) if snippet == "{" => true,
3180 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3183 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3188 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3192 return (err, candidates);
3194 (Def::Union(..), _) |
3195 (Def::Variant(..), _) |
3196 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3197 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3199 return (err, candidates);
3201 (Def::SelfTy(..), _) if ns == ValueNS => {
3202 err.span_label(span, fallback_label);
3203 err.note("can't use `Self` as a constructor, you must use the \
3204 implemented struct");
3205 return (err, candidates);
3207 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3208 err.note("can't use a type alias as a constructor");
3209 return (err, candidates);
3216 if !levenshtein_worked {
3217 err.span_label(base_span, fallback_label);
3218 this.type_ascription_suggestion(&mut err, base_span);
3222 let report_errors = |this: &mut Self, def: Option<Def>| {
3223 let (err, candidates) = report_errors(this, def);
3224 let def_id = this.current_module.normal_ancestor_id;
3225 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3226 let better = def.is_some();
3227 this.use_injections.push(UseError { err, candidates, node_id, better });
3228 err_path_resolution()
3231 let resolution = match self.resolve_qpath_anywhere(
3237 source.defer_to_typeck(),
3238 source.global_by_default(),
3241 Some(resolution) if resolution.unresolved_segments() == 0 => {
3242 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3245 // Add a temporary hack to smooth the transition to new struct ctor
3246 // visibility rules. See #38932 for more details.
3248 if let Def::Struct(def_id) = resolution.base_def() {
3249 if let Some((ctor_def, ctor_vis))
3250 = self.struct_constructors.get(&def_id).cloned() {
3251 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3252 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3253 self.session.buffer_lint(lint, id, span,
3254 "private struct constructors are not usable through \
3255 re-exports in outer modules",
3257 res = Some(PathResolution::new(ctor_def));
3262 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3265 Some(resolution) if source.defer_to_typeck() => {
3266 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3267 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3268 // it needs to be added to the trait map.
3270 let item_name = *path.last().unwrap();
3271 let traits = self.get_traits_containing_item(item_name, ns);
3272 self.trait_map.insert(id, traits);
3276 _ => report_errors(self, None)
3279 if let PathSource::TraitItem(..) = source {} else {
3280 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3281 self.record_def(id, resolution);
3286 fn type_ascription_suggestion(&self,
3287 err: &mut DiagnosticBuilder,
3289 debug!("type_ascription_suggetion {:?}", base_span);
3290 let cm = self.session.source_map();
3291 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3292 if let Some(sp) = self.current_type_ascription.last() {
3294 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3295 sp = cm.next_point(sp);
3296 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3297 debug!("snippet {:?}", snippet);
3298 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3299 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3300 debug!("{:?} {:?}", line_sp, line_base_sp);
3302 err.span_label(base_span,
3303 "expecting a type here because of type ascription");
3304 if line_sp != line_base_sp {
3305 err.span_suggestion_short_with_applicability(
3307 "did you mean to use `;` here instead?",
3309 Applicability::MaybeIncorrect,
3313 } else if snippet.trim().len() != 0 {
3314 debug!("tried to find type ascription `:` token, couldn't find it");
3324 fn self_type_is_available(&mut self, span: Span) -> bool {
3325 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3326 TypeNS, None, span);
3327 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3330 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3331 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3332 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3333 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3336 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3337 fn resolve_qpath_anywhere(&mut self,
3339 qself: Option<&QSelf>,
3341 primary_ns: Namespace,
3343 defer_to_typeck: bool,
3344 global_by_default: bool,
3345 crate_lint: CrateLint)
3346 -> Option<PathResolution> {
3347 let mut fin_res = None;
3348 // FIXME: can't resolve paths in macro namespace yet, macros are
3349 // processed by the little special hack below.
3350 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3351 if i == 0 || ns != primary_ns {
3352 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3353 // If defer_to_typeck, then resolution > no resolution,
3354 // otherwise full resolution > partial resolution > no resolution.
3355 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3357 res => if fin_res.is_none() { fin_res = res },
3361 if primary_ns != MacroNS &&
3362 (self.macro_names.contains(&path[0].modern()) ||
3363 self.builtin_macros.get(&path[0].name).cloned()
3364 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3365 self.macro_use_prelude.get(&path[0].name).cloned()
3366 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3367 // Return some dummy definition, it's enough for error reporting.
3369 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3375 /// Handles paths that may refer to associated items.
3376 fn resolve_qpath(&mut self,
3378 qself: Option<&QSelf>,
3382 global_by_default: bool,
3383 crate_lint: CrateLint)
3384 -> Option<PathResolution> {
3386 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3387 ns={:?}, span={:?}, global_by_default={:?})",
3396 if let Some(qself) = qself {
3397 if qself.position == 0 {
3398 // This is a case like `<T>::B`, where there is no
3399 // trait to resolve. In that case, we leave the `B`
3400 // segment to be resolved by type-check.
3401 return Some(PathResolution::with_unresolved_segments(
3402 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3406 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3408 // Currently, `path` names the full item (`A::B::C`, in
3409 // our example). so we extract the prefix of that that is
3410 // the trait (the slice upto and including
3411 // `qself.position`). And then we recursively resolve that,
3412 // but with `qself` set to `None`.
3414 // However, setting `qself` to none (but not changing the
3415 // span) loses the information about where this path
3416 // *actually* appears, so for the purposes of the crate
3417 // lint we pass along information that this is the trait
3418 // name from a fully qualified path, and this also
3419 // contains the full span (the `CrateLint::QPathTrait`).
3420 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3421 let res = self.smart_resolve_path_fragment(
3424 &path[..qself.position + 1],
3426 PathSource::TraitItem(ns),
3427 CrateLint::QPathTrait {
3429 qpath_span: qself.path_span,
3433 // The remaining segments (the `C` in our example) will
3434 // have to be resolved by type-check, since that requires doing
3435 // trait resolution.
3436 return Some(PathResolution::with_unresolved_segments(
3437 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3441 let result = match self.resolve_path(
3449 PathResult::NonModule(path_res) => path_res,
3450 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3451 PathResolution::new(module.def().unwrap())
3453 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3454 // don't report an error right away, but try to fallback to a primitive type.
3455 // So, we are still able to successfully resolve something like
3457 // use std::u8; // bring module u8 in scope
3458 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3459 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3460 // // not to non-existent std::u8::max_value
3463 // Such behavior is required for backward compatibility.
3464 // The same fallback is used when `a` resolves to nothing.
3465 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3466 PathResult::Failed(..)
3467 if (ns == TypeNS || path.len() > 1) &&
3468 self.primitive_type_table.primitive_types
3469 .contains_key(&path[0].name) => {
3470 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3471 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3473 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3474 PathResolution::new(module.def().unwrap()),
3475 PathResult::Failed(span, msg, false) => {
3476 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3477 err_path_resolution()
3479 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3480 PathResult::Failed(..) => return None,
3481 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3484 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3485 path[0].name != keywords::CrateRoot.name() &&
3486 path[0].name != keywords::DollarCrate.name() {
3487 let unqualified_result = {
3488 match self.resolve_path(
3490 &[*path.last().unwrap()],
3496 PathResult::NonModule(path_res) => path_res.base_def(),
3497 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3498 module.def().unwrap(),
3499 _ => return Some(result),
3502 if result.base_def() == unqualified_result {
3503 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3504 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3513 base_module: Option<ModuleOrUniformRoot<'a>>,
3515 opt_ns: Option<Namespace>, // `None` indicates a module path
3518 crate_lint: CrateLint,
3519 ) -> PathResult<'a> {
3520 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3521 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3522 record_used, path_span, crate_lint)
3525 fn resolve_path_with_parent_scope(
3527 base_module: Option<ModuleOrUniformRoot<'a>>,
3529 opt_ns: Option<Namespace>, // `None` indicates a module path
3530 parent_scope: &ParentScope<'a>,
3533 crate_lint: CrateLint,
3534 ) -> PathResult<'a> {
3535 let mut module = base_module;
3536 let mut allow_super = true;
3537 let mut second_binding = None;
3538 self.current_module = parent_scope.module;
3541 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3542 path_span={:?}, crate_lint={:?})",
3550 for (i, &ident) in path.iter().enumerate() {
3551 debug!("resolve_path ident {} {:?}", i, ident);
3552 let is_last = i == path.len() - 1;
3553 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3554 let name = ident.name;
3556 allow_super &= ns == TypeNS &&
3557 (name == keywords::SelfValue.name() ||
3558 name == keywords::Super.name());
3561 if allow_super && name == keywords::Super.name() {
3562 let mut ctxt = ident.span.ctxt().modern();
3563 let self_module = match i {
3564 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3566 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3570 if let Some(self_module) = self_module {
3571 if let Some(parent) = self_module.parent {
3572 module = Some(ModuleOrUniformRoot::Module(
3573 self.resolve_self(&mut ctxt, parent)));
3577 let msg = "There are too many initial `super`s.".to_string();
3578 return PathResult::Failed(ident.span, msg, false);
3581 if name == keywords::SelfValue.name() {
3582 let mut ctxt = ident.span.ctxt().modern();
3583 module = Some(ModuleOrUniformRoot::Module(
3584 self.resolve_self(&mut ctxt, self.current_module)));
3587 if name == keywords::Extern.name() ||
3588 name == keywords::CrateRoot.name() &&
3589 self.session.rust_2018() {
3590 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3593 if name == keywords::CrateRoot.name() ||
3594 name == keywords::Crate.name() ||
3595 name == keywords::DollarCrate.name() {
3596 // `::a::b`, `crate::a::b` or `$crate::a::b`
3597 module = Some(ModuleOrUniformRoot::Module(
3598 self.resolve_crate_root(ident)));
3604 // Report special messages for path segment keywords in wrong positions.
3605 if ident.is_path_segment_keyword() && i != 0 {
3606 let name_str = if name == keywords::CrateRoot.name() {
3607 "crate root".to_string()
3609 format!("`{}`", name)
3611 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3612 format!("global paths cannot start with {}", name_str)
3614 format!("{} in paths can only be used in start position", name_str)
3616 return PathResult::Failed(ident.span, msg, false);
3619 let binding = if let Some(module) = module {
3620 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3621 } else if opt_ns == Some(MacroNS) {
3622 assert!(ns == TypeNS);
3623 self.resolve_lexical_macro_path_segment(ident, ns, None, parent_scope, record_used,
3624 record_used, path_span).map(|(b, _)| b)
3626 let record_used_id =
3627 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3628 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3629 // we found a locally-imported or available item/module
3630 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3631 // we found a local variable or type param
3632 Some(LexicalScopeBinding::Def(def))
3633 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3634 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3638 _ => Err(if record_used { Determined } else { Undetermined }),
3645 second_binding = Some(binding);
3647 let def = binding.def();
3648 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3649 if let Some(next_module) = binding.module() {
3650 module = Some(ModuleOrUniformRoot::Module(next_module));
3651 } else if def == Def::ToolMod && i + 1 != path.len() {
3652 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3653 return PathResult::NonModule(PathResolution::new(def));
3654 } else if def == Def::Err {
3655 return PathResult::NonModule(err_path_resolution());
3656 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3657 self.lint_if_path_starts_with_module(
3663 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3664 def, path.len() - i - 1
3667 return PathResult::Failed(ident.span,
3668 format!("Not a module `{}`", ident),
3672 Err(Undetermined) => return PathResult::Indeterminate,
3673 Err(Determined) => {
3674 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3675 if opt_ns.is_some() && !module.is_normal() {
3676 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3677 module.def().unwrap(), path.len() - i
3681 let module_def = match module {
3682 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3685 let msg = if module_def == self.graph_root.def() {
3686 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3687 let mut candidates =
3688 self.lookup_import_candidates(name, TypeNS, is_mod);
3689 candidates.sort_by_cached_key(|c| {
3690 (c.path.segments.len(), c.path.to_string())
3692 if let Some(candidate) = candidates.get(0) {
3693 format!("Did you mean `{}`?", candidate.path)
3695 format!("Maybe a missing `extern crate {};`?", ident)
3698 format!("Use of undeclared type or module `{}`", ident)
3700 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3702 return PathResult::Failed(ident.span, msg, is_last);
3707 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3709 PathResult::Module(module.unwrap_or_else(|| {
3710 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3715 fn lint_if_path_starts_with_module(
3717 crate_lint: CrateLint,
3720 second_binding: Option<&NameBinding>,
3722 // In the 2018 edition this lint is a hard error, so nothing to do
3723 if self.session.rust_2018() {
3727 let (diag_id, diag_span) = match crate_lint {
3728 CrateLint::No => return,
3729 CrateLint::SimplePath(id) => (id, path_span),
3730 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3731 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3734 let first_name = match path.get(0) {
3735 Some(ident) => ident.name,
3739 // We're only interested in `use` paths which should start with
3740 // `{{root}}` or `extern` currently.
3741 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3746 // If this import looks like `crate::...` it's already good
3747 Some(ident) if ident.name == keywords::Crate.name() => return,
3748 // Otherwise go below to see if it's an extern crate
3750 // If the path has length one (and it's `CrateRoot` most likely)
3751 // then we don't know whether we're gonna be importing a crate or an
3752 // item in our crate. Defer this lint to elsewhere
3756 // If the first element of our path was actually resolved to an
3757 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3758 // warning, this looks all good!
3759 if let Some(binding) = second_binding {
3760 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3761 // Careful: we still want to rewrite paths from
3762 // renamed extern crates.
3763 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3769 let diag = lint::builtin::BuiltinLintDiagnostics
3770 ::AbsPathWithModule(diag_span);
3771 self.session.buffer_lint_with_diagnostic(
3772 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3774 "absolute paths must start with `self`, `super`, \
3775 `crate`, or an external crate name in the 2018 edition",
3779 // Resolve a local definition, potentially adjusting for closures.
3780 fn adjust_local_def(&mut self,
3785 span: Span) -> Def {
3786 let ribs = &self.ribs[ns][rib_index + 1..];
3788 // An invalid forward use of a type parameter from a previous default.
3789 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3791 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3793 assert_eq!(def, Def::Err);
3799 span_bug!(span, "unexpected {:?} in bindings", def)
3801 Def::Local(node_id) => {
3804 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3805 ForwardTyParamBanRibKind => {
3806 // Nothing to do. Continue.
3808 ClosureRibKind(function_id) => {
3811 let seen = self.freevars_seen
3814 if let Some(&index) = seen.get(&node_id) {
3815 def = Def::Upvar(node_id, index, function_id);
3818 let vec = self.freevars
3821 let depth = vec.len();
3822 def = Def::Upvar(node_id, depth, function_id);
3829 seen.insert(node_id, depth);
3832 ItemRibKind | TraitOrImplItemRibKind => {
3833 // This was an attempt to access an upvar inside a
3834 // named function item. This is not allowed, so we
3837 resolve_error(self, span,
3838 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3842 ConstantItemRibKind => {
3843 // Still doesn't deal with upvars
3845 resolve_error(self, span,
3846 ResolutionError::AttemptToUseNonConstantValueInConstant);
3853 Def::TyParam(..) | Def::SelfTy(..) => {
3856 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3857 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3858 ConstantItemRibKind => {
3859 // Nothing to do. Continue.
3862 // This was an attempt to use a type parameter outside
3865 resolve_error(self, span,
3866 ResolutionError::TypeParametersFromOuterFunction(def));
3878 fn lookup_assoc_candidate<FilterFn>(&mut self,
3881 filter_fn: FilterFn)
3882 -> Option<AssocSuggestion>
3883 where FilterFn: Fn(Def) -> bool
3885 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3887 TyKind::Path(None, _) => Some(t.id),
3888 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3889 // This doesn't handle the remaining `Ty` variants as they are not
3890 // that commonly the self_type, it might be interesting to provide
3891 // support for those in future.
3896 // Fields are generally expected in the same contexts as locals.
3897 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3898 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3899 // Look for a field with the same name in the current self_type.
3900 if let Some(resolution) = self.def_map.get(&node_id) {
3901 match resolution.base_def() {
3902 Def::Struct(did) | Def::Union(did)
3903 if resolution.unresolved_segments() == 0 => {
3904 if let Some(field_names) = self.field_names.get(&did) {
3905 if field_names.iter().any(|&field_name| ident.name == field_name) {
3906 return Some(AssocSuggestion::Field);
3916 // Look for associated items in the current trait.
3917 if let Some((module, _)) = self.current_trait_ref {
3918 if let Ok(binding) = self.resolve_ident_in_module(
3919 ModuleOrUniformRoot::Module(module),
3925 let def = binding.def();
3927 return Some(if self.has_self.contains(&def.def_id()) {
3928 AssocSuggestion::MethodWithSelf
3930 AssocSuggestion::AssocItem
3939 fn lookup_typo_candidate<FilterFn>(&mut self,
3942 filter_fn: FilterFn,
3945 where FilterFn: Fn(Def) -> bool
3947 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3948 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3949 if let Some(binding) = resolution.borrow().binding {
3950 if filter_fn(binding.def()) {
3951 names.push(ident.name);
3957 let mut names = Vec::new();
3958 if path.len() == 1 {
3959 // Search in lexical scope.
3960 // Walk backwards up the ribs in scope and collect candidates.
3961 for rib in self.ribs[ns].iter().rev() {
3962 // Locals and type parameters
3963 for (ident, def) in &rib.bindings {
3964 if filter_fn(*def) {
3965 names.push(ident.name);
3969 if let ModuleRibKind(module) = rib.kind {
3970 // Items from this module
3971 add_module_candidates(module, &mut names);
3973 if let ModuleKind::Block(..) = module.kind {
3974 // We can see through blocks
3976 // Items from the prelude
3977 if !module.no_implicit_prelude {
3978 names.extend(self.extern_prelude.iter().cloned());
3979 if let Some(prelude) = self.prelude {
3980 add_module_candidates(prelude, &mut names);
3987 // Add primitive types to the mix
3988 if filter_fn(Def::PrimTy(Bool)) {
3990 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3994 // Search in module.
3995 let mod_path = &path[..path.len() - 1];
3996 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
3997 false, span, CrateLint::No) {
3998 if let ModuleOrUniformRoot::Module(module) = module {
3999 add_module_candidates(module, &mut names);
4004 let name = path[path.len() - 1].name;
4005 // Make sure error reporting is deterministic.
4006 names.sort_by_cached_key(|name| name.as_str());
4007 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4008 Some(found) if found != name => Some(found),
4013 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4014 where F: FnOnce(&mut Resolver)
4016 if let Some(label) = label {
4017 self.unused_labels.insert(id, label.ident.span);
4018 let def = Def::Label(id);
4019 self.with_label_rib(|this| {
4020 let ident = label.ident.modern_and_legacy();
4021 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4029 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4030 self.with_resolved_label(label, id, |this| this.visit_block(block));
4033 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4034 // First, record candidate traits for this expression if it could
4035 // result in the invocation of a method call.
4037 self.record_candidate_traits_for_expr_if_necessary(expr);
4039 // Next, resolve the node.
4041 ExprKind::Path(ref qself, ref path) => {
4042 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4043 visit::walk_expr(self, expr);
4046 ExprKind::Struct(ref path, ..) => {
4047 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4048 visit::walk_expr(self, expr);
4051 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4052 let def = self.search_label(label.ident, |rib, ident| {
4053 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4057 // Search again for close matches...
4058 // Picks the first label that is "close enough", which is not necessarily
4059 // the closest match
4060 let close_match = self.search_label(label.ident, |rib, ident| {
4061 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4062 find_best_match_for_name(names, &*ident.as_str(), None)
4064 self.record_def(expr.id, err_path_resolution());
4067 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4070 Some(Def::Label(id)) => {
4071 // Since this def is a label, it is never read.
4072 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4073 self.unused_labels.remove(&id);
4076 span_bug!(expr.span, "label wasn't mapped to a label def!");
4080 // visit `break` argument if any
4081 visit::walk_expr(self, expr);
4084 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4085 self.visit_expr(subexpression);
4087 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4088 let mut bindings_list = FxHashMap();
4090 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4092 // This has to happen *after* we determine which pat_idents are variants
4093 self.check_consistent_bindings(pats);
4094 self.visit_block(if_block);
4095 self.ribs[ValueNS].pop();
4097 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4100 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4102 ExprKind::While(ref subexpression, ref block, label) => {
4103 self.with_resolved_label(label, expr.id, |this| {
4104 this.visit_expr(subexpression);
4105 this.visit_block(block);
4109 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4110 self.with_resolved_label(label, expr.id, |this| {
4111 this.visit_expr(subexpression);
4112 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4113 let mut bindings_list = FxHashMap();
4115 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4117 // This has to happen *after* we determine which pat_idents are variants
4118 this.check_consistent_bindings(pats);
4119 this.visit_block(block);
4120 this.ribs[ValueNS].pop();
4124 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4125 self.visit_expr(subexpression);
4126 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4127 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4129 self.resolve_labeled_block(label, expr.id, block);
4131 self.ribs[ValueNS].pop();
4134 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4136 // Equivalent to `visit::walk_expr` + passing some context to children.
4137 ExprKind::Field(ref subexpression, _) => {
4138 self.resolve_expr(subexpression, Some(expr));
4140 ExprKind::MethodCall(ref segment, ref arguments) => {
4141 let mut arguments = arguments.iter();
4142 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4143 for argument in arguments {
4144 self.resolve_expr(argument, None);
4146 self.visit_path_segment(expr.span, segment);
4149 ExprKind::Call(ref callee, ref arguments) => {
4150 self.resolve_expr(callee, Some(expr));
4151 for argument in arguments {
4152 self.resolve_expr(argument, None);
4155 ExprKind::Type(ref type_expr, _) => {
4156 self.current_type_ascription.push(type_expr.span);
4157 visit::walk_expr(self, expr);
4158 self.current_type_ascription.pop();
4160 // Resolve the body of async exprs inside the async closure to which they desugar
4161 ExprKind::Async(_, async_closure_id, ref block) => {
4162 let rib_kind = ClosureRibKind(async_closure_id);
4163 self.ribs[ValueNS].push(Rib::new(rib_kind));
4164 self.label_ribs.push(Rib::new(rib_kind));
4165 self.visit_block(&block);
4166 self.label_ribs.pop();
4167 self.ribs[ValueNS].pop();
4169 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4170 // resolve the arguments within the proper scopes so that usages of them inside the
4171 // closure are detected as upvars rather than normal closure arg usages.
4173 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4174 ref fn_decl, ref body, _span,
4176 let rib_kind = ClosureRibKind(expr.id);
4177 self.ribs[ValueNS].push(Rib::new(rib_kind));
4178 self.label_ribs.push(Rib::new(rib_kind));
4179 // Resolve arguments:
4180 let mut bindings_list = FxHashMap();
4181 for argument in &fn_decl.inputs {
4182 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4183 self.visit_ty(&argument.ty);
4185 // No need to resolve return type-- the outer closure return type is
4186 // FunctionRetTy::Default
4188 // Now resolve the inner closure
4190 let rib_kind = ClosureRibKind(inner_closure_id);
4191 self.ribs[ValueNS].push(Rib::new(rib_kind));
4192 self.label_ribs.push(Rib::new(rib_kind));
4193 // No need to resolve arguments: the inner closure has none.
4194 // Resolve the return type:
4195 visit::walk_fn_ret_ty(self, &fn_decl.output);
4197 self.visit_expr(body);
4198 self.label_ribs.pop();
4199 self.ribs[ValueNS].pop();
4201 self.label_ribs.pop();
4202 self.ribs[ValueNS].pop();
4205 visit::walk_expr(self, expr);
4210 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4212 ExprKind::Field(_, ident) => {
4213 // FIXME(#6890): Even though you can't treat a method like a
4214 // field, we need to add any trait methods we find that match
4215 // the field name so that we can do some nice error reporting
4216 // later on in typeck.
4217 let traits = self.get_traits_containing_item(ident, ValueNS);
4218 self.trait_map.insert(expr.id, traits);
4220 ExprKind::MethodCall(ref segment, ..) => {
4221 debug!("(recording candidate traits for expr) recording traits for {}",
4223 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4224 self.trait_map.insert(expr.id, traits);
4232 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4233 -> Vec<TraitCandidate> {
4234 debug!("(getting traits containing item) looking for '{}'", ident.name);
4236 let mut found_traits = Vec::new();
4237 // Look for the current trait.
4238 if let Some((module, _)) = self.current_trait_ref {
4239 if self.resolve_ident_in_module(
4240 ModuleOrUniformRoot::Module(module),
4246 let def_id = module.def_id().unwrap();
4247 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4251 ident.span = ident.span.modern();
4252 let mut search_module = self.current_module;
4254 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4255 search_module = unwrap_or!(
4256 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4260 if let Some(prelude) = self.prelude {
4261 if !search_module.no_implicit_prelude {
4262 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4269 fn get_traits_in_module_containing_item(&mut self,
4273 found_traits: &mut Vec<TraitCandidate>) {
4274 assert!(ns == TypeNS || ns == ValueNS);
4275 let mut traits = module.traits.borrow_mut();
4276 if traits.is_none() {
4277 let mut collected_traits = Vec::new();
4278 module.for_each_child(|name, ns, binding| {
4279 if ns != TypeNS { return }
4280 if let Def::Trait(_) = binding.def() {
4281 collected_traits.push((name, binding));
4284 *traits = Some(collected_traits.into_boxed_slice());
4287 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4288 let module = binding.module().unwrap();
4289 let mut ident = ident;
4290 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4293 if self.resolve_ident_in_module_unadjusted(
4294 ModuleOrUniformRoot::Module(module),
4301 let import_id = match binding.kind {
4302 NameBindingKind::Import { directive, .. } => {
4303 self.maybe_unused_trait_imports.insert(directive.id);
4304 self.add_to_glob_map(directive.id, trait_name);
4309 let trait_def_id = module.def_id().unwrap();
4310 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4315 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4317 namespace: Namespace,
4318 start_module: &'a ModuleData<'a>,
4320 filter_fn: FilterFn)
4321 -> Vec<ImportSuggestion>
4322 where FilterFn: Fn(Def) -> bool
4324 let mut candidates = Vec::new();
4325 let mut worklist = Vec::new();
4326 let mut seen_modules = FxHashSet();
4327 let not_local_module = crate_name != keywords::Crate.ident();
4328 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4330 while let Some((in_module,
4332 in_module_is_extern)) = worklist.pop() {
4333 self.populate_module_if_necessary(in_module);
4335 // We have to visit module children in deterministic order to avoid
4336 // instabilities in reported imports (#43552).
4337 in_module.for_each_child_stable(|ident, ns, name_binding| {
4338 // avoid imports entirely
4339 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4340 // avoid non-importable candidates as well
4341 if !name_binding.is_importable() { return; }
4343 // collect results based on the filter function
4344 if ident.name == lookup_name && ns == namespace {
4345 if filter_fn(name_binding.def()) {
4347 let mut segms = path_segments.clone();
4348 if self.session.rust_2018() {
4349 // crate-local absolute paths start with `crate::` in edition 2018
4350 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4352 0, ast::PathSegment::from_ident(crate_name)
4356 segms.push(ast::PathSegment::from_ident(ident));
4358 span: name_binding.span,
4361 // the entity is accessible in the following cases:
4362 // 1. if it's defined in the same crate, it's always
4363 // accessible (since private entities can be made public)
4364 // 2. if it's defined in another crate, it's accessible
4365 // only if both the module is public and the entity is
4366 // declared as public (due to pruning, we don't explore
4367 // outside crate private modules => no need to check this)
4368 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4369 candidates.push(ImportSuggestion { path: path });
4374 // collect submodules to explore
4375 if let Some(module) = name_binding.module() {
4377 let mut path_segments = path_segments.clone();
4378 path_segments.push(ast::PathSegment::from_ident(ident));
4380 let is_extern_crate_that_also_appears_in_prelude =
4381 name_binding.is_extern_crate() &&
4382 self.session.rust_2018();
4384 let is_visible_to_user =
4385 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4387 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4388 // add the module to the lookup
4389 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4390 if seen_modules.insert(module.def_id().unwrap()) {
4391 worklist.push((module, path_segments, is_extern));
4401 /// When name resolution fails, this method can be used to look up candidate
4402 /// entities with the expected name. It allows filtering them using the
4403 /// supplied predicate (which should be used to only accept the types of
4404 /// definitions expected e.g. traits). The lookup spans across all crates.
4406 /// NOTE: The method does not look into imports, but this is not a problem,
4407 /// since we report the definitions (thus, the de-aliased imports).
4408 fn lookup_import_candidates<FilterFn>(&mut self,
4410 namespace: Namespace,
4411 filter_fn: FilterFn)
4412 -> Vec<ImportSuggestion>
4413 where FilterFn: Fn(Def) -> bool
4415 let mut suggestions = vec![];
4418 self.lookup_import_candidates_from_module(
4419 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4423 if self.session.rust_2018() {
4424 let extern_prelude_names = self.extern_prelude.clone();
4425 for &name in extern_prelude_names.iter() {
4426 let ident = Ident::with_empty_ctxt(name);
4427 match self.crate_loader.maybe_process_path_extern(name, ident.span) {
4429 let crate_root = self.get_module(DefId {
4431 index: CRATE_DEF_INDEX,
4433 self.populate_module_if_necessary(&crate_root);
4436 self.lookup_import_candidates_from_module(
4437 lookup_name, namespace, crate_root, ident, &filter_fn
4449 fn find_module(&mut self,
4451 -> Option<(Module<'a>, ImportSuggestion)>
4453 let mut result = None;
4454 let mut worklist = Vec::new();
4455 let mut seen_modules = FxHashSet();
4456 worklist.push((self.graph_root, Vec::new()));
4458 while let Some((in_module, path_segments)) = worklist.pop() {
4459 // abort if the module is already found
4460 if result.is_some() { break; }
4462 self.populate_module_if_necessary(in_module);
4464 in_module.for_each_child_stable(|ident, _, name_binding| {
4465 // abort if the module is already found or if name_binding is private external
4466 if result.is_some() || !name_binding.vis.is_visible_locally() {
4469 if let Some(module) = name_binding.module() {
4471 let mut path_segments = path_segments.clone();
4472 path_segments.push(ast::PathSegment::from_ident(ident));
4473 if module.def() == Some(module_def) {
4475 span: name_binding.span,
4476 segments: path_segments,
4478 result = Some((module, ImportSuggestion { path: path }));
4480 // add the module to the lookup
4481 if seen_modules.insert(module.def_id().unwrap()) {
4482 worklist.push((module, path_segments));
4492 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4493 if let Def::Enum(..) = enum_def {} else {
4494 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4497 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4498 self.populate_module_if_necessary(enum_module);
4500 let mut variants = Vec::new();
4501 enum_module.for_each_child_stable(|ident, _, name_binding| {
4502 if let Def::Variant(..) = name_binding.def() {
4503 let mut segms = enum_import_suggestion.path.segments.clone();
4504 segms.push(ast::PathSegment::from_ident(ident));
4505 variants.push(Path {
4506 span: name_binding.span,
4515 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4516 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4517 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4518 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4522 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4524 ast::VisibilityKind::Public => ty::Visibility::Public,
4525 ast::VisibilityKind::Crate(..) => {
4526 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4528 ast::VisibilityKind::Inherited => {
4529 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4531 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4532 // Visibilities are resolved as global by default, add starting root segment.
4533 let segments = path.make_root().iter().chain(path.segments.iter())
4534 .map(|seg| seg.ident)
4535 .collect::<Vec<_>>();
4536 let def = self.smart_resolve_path_fragment(
4541 PathSource::Visibility,
4542 CrateLint::SimplePath(id),
4544 if def == Def::Err {
4545 ty::Visibility::Public
4547 let vis = ty::Visibility::Restricted(def.def_id());
4548 if self.is_accessible(vis) {
4551 self.session.span_err(path.span, "visibilities can only be restricted \
4552 to ancestor modules");
4553 ty::Visibility::Public
4560 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4561 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4564 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4565 vis.is_accessible_from(module.normal_ancestor_id, self)
4568 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4569 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4571 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4573 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4574 let note = if b1.expansion != Mark::root() {
4575 Some(if let Def::Macro(..) = b1.def() {
4576 format!("macro-expanded {} do not shadow",
4577 if b1.is_import() { "macro imports" } else { "macros" })
4579 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4580 if b1.is_import() { "imports" } else { "items" })
4582 } else if b1.is_glob_import() {
4583 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4588 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4589 err.span_label(ident.span, "ambiguous name");
4590 err.span_note(b1.span, &msg1);
4592 Def::Macro(..) if b2.span.is_dummy() =>
4593 err.note(&format!("`{}` is also a builtin macro", ident)),
4594 _ => err.span_note(b2.span, &msg2),
4596 if let Some(note) = note {
4602 fn report_errors(&mut self, krate: &Crate) {
4603 self.report_with_use_injections(krate);
4604 let mut reported_spans = FxHashSet();
4606 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4607 let msg = "macro-expanded `macro_export` macros from the current crate \
4608 cannot be referred to by absolute paths";
4609 self.session.buffer_lint_with_diagnostic(
4610 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4611 CRATE_NODE_ID, span_use, msg,
4612 lint::builtin::BuiltinLintDiagnostics::
4613 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4617 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4618 if reported_spans.insert(ident.span) {
4619 self.report_ambiguity_error(ident, b1, b2);
4623 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4624 if !reported_spans.insert(span) { continue }
4625 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4629 fn report_with_use_injections(&mut self, krate: &Crate) {
4630 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4631 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4632 if !candidates.is_empty() {
4633 show_candidates(&mut err, span, &candidates, better, found_use);
4639 fn report_conflict<'b>(&mut self,
4643 new_binding: &NameBinding<'b>,
4644 old_binding: &NameBinding<'b>) {
4645 // Error on the second of two conflicting names
4646 if old_binding.span.lo() > new_binding.span.lo() {
4647 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4650 let container = match parent.kind {
4651 ModuleKind::Def(Def::Mod(_), _) => "module",
4652 ModuleKind::Def(Def::Trait(_), _) => "trait",
4653 ModuleKind::Block(..) => "block",
4657 let old_noun = match old_binding.is_import() {
4659 false => "definition",
4662 let new_participle = match new_binding.is_import() {
4667 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4669 if let Some(s) = self.name_already_seen.get(&name) {
4675 let old_kind = match (ns, old_binding.module()) {
4676 (ValueNS, _) => "value",
4677 (MacroNS, _) => "macro",
4678 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4679 (TypeNS, Some(module)) if module.is_normal() => "module",
4680 (TypeNS, Some(module)) if module.is_trait() => "trait",
4681 (TypeNS, _) => "type",
4684 let msg = format!("the name `{}` is defined multiple times", name);
4686 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4687 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4688 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4689 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4690 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4692 _ => match (old_binding.is_import(), new_binding.is_import()) {
4693 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4694 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4695 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4699 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4704 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4705 if !old_binding.span.is_dummy() {
4706 err.span_label(self.session.source_map().def_span(old_binding.span),
4707 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4710 // See https://github.com/rust-lang/rust/issues/32354
4711 if old_binding.is_import() || new_binding.is_import() {
4712 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4718 let cm = self.session.source_map();
4719 let rename_msg = "You can use `as` to change the binding name of the import";
4721 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4722 binding.is_renamed_extern_crate()) {
4723 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4724 format!("Other{}", name)
4726 format!("other_{}", name)
4729 err.span_suggestion_with_applicability(
4732 if snippet.ends_with(';') {
4733 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4735 format!("{} as {}", snippet, suggested_name)
4737 Applicability::MachineApplicable,
4740 err.span_label(binding.span, rename_msg);
4745 self.name_already_seen.insert(name, span);
4749 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4750 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4753 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4754 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4757 fn names_to_string(idents: &[Ident]) -> String {
4758 let mut result = String::new();
4759 for (i, ident) in idents.iter()
4760 .filter(|ident| ident.name != keywords::CrateRoot.name())
4763 result.push_str("::");
4765 result.push_str(&ident.as_str());
4770 fn path_names_to_string(path: &Path) -> String {
4771 names_to_string(&path.segments.iter()
4772 .map(|seg| seg.ident)
4773 .collect::<Vec<_>>())
4776 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4777 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4778 let variant_path = &suggestion.path;
4779 let variant_path_string = path_names_to_string(variant_path);
4781 let path_len = suggestion.path.segments.len();
4782 let enum_path = ast::Path {
4783 span: suggestion.path.span,
4784 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4786 let enum_path_string = path_names_to_string(&enum_path);
4788 (suggestion.path.span, variant_path_string, enum_path_string)
4792 /// When an entity with a given name is not available in scope, we search for
4793 /// entities with that name in all crates. This method allows outputting the
4794 /// results of this search in a programmer-friendly way
4795 fn show_candidates(err: &mut DiagnosticBuilder,
4796 // This is `None` if all placement locations are inside expansions
4798 candidates: &[ImportSuggestion],
4802 // we want consistent results across executions, but candidates are produced
4803 // by iterating through a hash map, so make sure they are ordered:
4804 let mut path_strings: Vec<_> =
4805 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4806 path_strings.sort();
4808 let better = if better { "better " } else { "" };
4809 let msg_diff = match path_strings.len() {
4810 1 => " is found in another module, you can import it",
4811 _ => "s are found in other modules, you can import them",
4813 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4815 if let Some(span) = span {
4816 for candidate in &mut path_strings {
4817 // produce an additional newline to separate the new use statement
4818 // from the directly following item.
4819 let additional_newline = if found_use {
4824 *candidate = format!("use {};\n{}", candidate, additional_newline);
4827 err.span_suggestions_with_applicability(
4831 Applicability::Unspecified,
4836 for candidate in path_strings {
4838 msg.push_str(&candidate);
4843 /// A somewhat inefficient routine to obtain the name of a module.
4844 fn module_to_string(module: Module) -> Option<String> {
4845 let mut names = Vec::new();
4847 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4848 if let ModuleKind::Def(_, name) = module.kind {
4849 if let Some(parent) = module.parent {
4850 names.push(Ident::with_empty_ctxt(name));
4851 collect_mod(names, parent);
4854 // danger, shouldn't be ident?
4855 names.push(Ident::from_str("<opaque>"));
4856 collect_mod(names, module.parent.unwrap());
4859 collect_mod(&mut names, module);
4861 if names.is_empty() {
4864 Some(names_to_string(&names.into_iter()
4866 .collect::<Vec<_>>()))
4869 fn err_path_resolution() -> PathResolution {
4870 PathResolution::new(Def::Err)
4873 #[derive(PartialEq,Copy, Clone)]
4874 pub enum MakeGlobMap {
4879 #[derive(Copy, Clone, Debug)]
4881 /// Do not issue the lint
4884 /// This lint applies to some random path like `impl ::foo::Bar`
4885 /// or whatever. In this case, we can take the span of that path.
4888 /// This lint comes from a `use` statement. In this case, what we
4889 /// care about really is the *root* `use` statement; e.g., if we
4890 /// have nested things like `use a::{b, c}`, we care about the
4892 UsePath { root_id: NodeId, root_span: Span },
4894 /// This is the "trait item" from a fully qualified path. For example,
4895 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4896 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4897 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4901 fn node_id(&self) -> Option<NodeId> {
4903 CrateLint::No => None,
4904 CrateLint::SimplePath(id) |
4905 CrateLint::UsePath { root_id: id, .. } |
4906 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4911 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }