1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
16 #![cfg_attr(not(stage0), feature(nll))]
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};
46 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
47 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
49 use rustc_metadata::creader::CrateLoader;
50 use rustc_metadata::cstore::CStore;
52 use syntax::source_map::SourceMap;
53 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
54 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
55 use syntax::ext::base::SyntaxExtension;
56 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
57 use syntax::ext::base::MacroKind;
58 use syntax::symbol::{Symbol, keywords};
59 use syntax::util::lev_distance::find_best_match_for_name;
61 use syntax::visit::{self, FnKind, Visitor};
63 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
64 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
65 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
66 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
67 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
68 use syntax::feature_gate::{feature_err, GateIssue};
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, LegacyScope};
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(..) => true,
564 PathSource::Pat => match def {
565 Def::StructCtor(_, CtorKind::Const) |
566 Def::VariantCtor(_, CtorKind::Const) |
567 Def::Const(..) | Def::AssociatedConst(..) => true,
570 PathSource::TupleStruct => match def {
571 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
574 PathSource::Struct => match def {
575 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
576 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
579 PathSource::TraitItem(ns) => match def {
580 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
581 Def::AssociatedTy(..) if ns == TypeNS => true,
584 PathSource::ImportPrefix => match def {
585 Def::Mod(..) | Def::Enum(..) => true,
588 PathSource::Visibility => match def {
589 Def::Mod(..) => true,
595 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
596 __diagnostic_used!(E0404);
597 __diagnostic_used!(E0405);
598 __diagnostic_used!(E0412);
599 __diagnostic_used!(E0422);
600 __diagnostic_used!(E0423);
601 __diagnostic_used!(E0425);
602 __diagnostic_used!(E0531);
603 __diagnostic_used!(E0532);
604 __diagnostic_used!(E0573);
605 __diagnostic_used!(E0574);
606 __diagnostic_used!(E0575);
607 __diagnostic_used!(E0576);
608 __diagnostic_used!(E0577);
609 __diagnostic_used!(E0578);
610 match (self, has_unexpected_resolution) {
611 (PathSource::Trait(_), true) => "E0404",
612 (PathSource::Trait(_), false) => "E0405",
613 (PathSource::Type, true) => "E0573",
614 (PathSource::Type, false) => "E0412",
615 (PathSource::Struct, true) => "E0574",
616 (PathSource::Struct, false) => "E0422",
617 (PathSource::Expr(..), true) => "E0423",
618 (PathSource::Expr(..), false) => "E0425",
619 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
620 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
621 (PathSource::TraitItem(..), true) => "E0575",
622 (PathSource::TraitItem(..), false) => "E0576",
623 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
624 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
629 struct UsePlacementFinder {
630 target_module: NodeId,
635 impl UsePlacementFinder {
636 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
637 let mut finder = UsePlacementFinder {
642 visit::walk_crate(&mut finder, krate);
643 (finder.span, finder.found_use)
647 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
650 module: &'tcx ast::Mod,
652 _: &[ast::Attribute],
655 if self.span.is_some() {
658 if node_id != self.target_module {
659 visit::walk_mod(self, module);
662 // find a use statement
663 for item in &module.items {
665 ItemKind::Use(..) => {
666 // don't suggest placing a use before the prelude
667 // import or other generated ones
668 if item.span.ctxt().outer().expn_info().is_none() {
669 self.span = Some(item.span.shrink_to_lo());
670 self.found_use = true;
674 // don't place use before extern crate
675 ItemKind::ExternCrate(_) => {}
676 // but place them before the first other item
677 _ => if self.span.map_or(true, |span| item.span < span ) {
678 if item.span.ctxt().outer().expn_info().is_none() {
679 // don't insert between attributes and an item
680 if item.attrs.is_empty() {
681 self.span = Some(item.span.shrink_to_lo());
683 // find the first attribute on the item
684 for attr in &item.attrs {
685 if self.span.map_or(true, |span| attr.span < span) {
686 self.span = Some(attr.span.shrink_to_lo());
697 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
698 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
699 fn visit_item(&mut self, item: &'tcx Item) {
700 self.resolve_item(item);
702 fn visit_arm(&mut self, arm: &'tcx Arm) {
703 self.resolve_arm(arm);
705 fn visit_block(&mut self, block: &'tcx Block) {
706 self.resolve_block(block);
708 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
709 self.with_constant_rib(|this| {
710 visit::walk_anon_const(this, constant);
713 fn visit_expr(&mut self, expr: &'tcx Expr) {
714 self.resolve_expr(expr, None);
716 fn visit_local(&mut self, local: &'tcx Local) {
717 self.resolve_local(local);
719 fn visit_ty(&mut self, ty: &'tcx Ty) {
721 TyKind::Path(ref qself, ref path) => {
722 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
724 TyKind::ImplicitSelf => {
725 let self_ty = keywords::SelfType.ident();
726 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
727 .map_or(Def::Err, |d| d.def());
728 self.record_def(ty.id, PathResolution::new(def));
732 visit::walk_ty(self, ty);
734 fn visit_poly_trait_ref(&mut self,
735 tref: &'tcx ast::PolyTraitRef,
736 m: &'tcx ast::TraitBoundModifier) {
737 self.smart_resolve_path(tref.trait_ref.ref_id, None,
738 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
739 visit::walk_poly_trait_ref(self, tref, m);
741 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
742 let type_parameters = match foreign_item.node {
743 ForeignItemKind::Fn(_, ref generics) => {
744 HasTypeParameters(generics, ItemRibKind)
746 ForeignItemKind::Static(..) => NoTypeParameters,
747 ForeignItemKind::Ty => NoTypeParameters,
748 ForeignItemKind::Macro(..) => NoTypeParameters,
750 self.with_type_parameter_rib(type_parameters, |this| {
751 visit::walk_foreign_item(this, foreign_item);
754 fn visit_fn(&mut self,
755 function_kind: FnKind<'tcx>,
756 declaration: &'tcx FnDecl,
760 let (rib_kind, asyncness) = match function_kind {
761 FnKind::ItemFn(_, ref header, ..) =>
762 (ItemRibKind, header.asyncness),
763 FnKind::Method(_, ref sig, _, _) =>
764 (TraitOrImplItemRibKind, sig.header.asyncness),
765 FnKind::Closure(_) =>
766 // Async closures aren't resolved through `visit_fn`-- they're
767 // processed separately
768 (ClosureRibKind(node_id), IsAsync::NotAsync),
771 // Create a value rib for the function.
772 self.ribs[ValueNS].push(Rib::new(rib_kind));
774 // Create a label rib for the function.
775 self.label_ribs.push(Rib::new(rib_kind));
777 // Add each argument to the rib.
778 let mut bindings_list = FxHashMap();
779 for argument in &declaration.inputs {
780 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
782 self.visit_ty(&argument.ty);
784 debug!("(resolving function) recorded argument");
786 visit::walk_fn_ret_ty(self, &declaration.output);
788 // Resolve the function body, potentially inside the body of an async closure
789 if let IsAsync::Async { closure_id, .. } = asyncness {
790 let rib_kind = ClosureRibKind(closure_id);
791 self.ribs[ValueNS].push(Rib::new(rib_kind));
792 self.label_ribs.push(Rib::new(rib_kind));
795 match function_kind {
796 FnKind::ItemFn(.., body) |
797 FnKind::Method(.., body) => {
798 self.visit_block(body);
800 FnKind::Closure(body) => {
801 self.visit_expr(body);
805 // Leave the body of the async closure
806 if asyncness.is_async() {
807 self.label_ribs.pop();
808 self.ribs[ValueNS].pop();
811 debug!("(resolving function) leaving function");
813 self.label_ribs.pop();
814 self.ribs[ValueNS].pop();
816 fn visit_generics(&mut self, generics: &'tcx Generics) {
817 // For type parameter defaults, we have to ban access
818 // to following type parameters, as the Substs can only
819 // provide previous type parameters as they're built. We
820 // put all the parameters on the ban list and then remove
821 // them one by one as they are processed and become available.
822 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
823 let mut found_default = false;
824 default_ban_rib.bindings.extend(generics.params.iter()
825 .filter_map(|param| match param.kind {
826 GenericParamKind::Lifetime { .. } => None,
827 GenericParamKind::Type { ref default, .. } => {
828 found_default |= default.is_some();
830 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
837 for param in &generics.params {
839 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
840 GenericParamKind::Type { ref default, .. } => {
841 for bound in ¶m.bounds {
842 self.visit_param_bound(bound);
845 if let Some(ref ty) = default {
846 self.ribs[TypeNS].push(default_ban_rib);
848 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
851 // Allow all following defaults to refer to this type parameter.
852 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
856 for p in &generics.where_clause.predicates {
857 self.visit_where_predicate(p);
862 #[derive(Copy, Clone)]
863 enum TypeParameters<'a, 'b> {
865 HasTypeParameters(// Type parameters.
868 // The kind of the rib used for type parameters.
872 /// The rib kind controls the translation of local
873 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
874 #[derive(Copy, Clone, Debug)]
876 /// No translation needs to be applied.
879 /// We passed through a closure scope at the given node ID.
880 /// Translate upvars as appropriate.
881 ClosureRibKind(NodeId /* func id */),
883 /// We passed through an impl or trait and are now in one of its
884 /// methods or associated types. Allow references to ty params that impl or trait
885 /// binds. Disallow any other upvars (including other ty params that are
887 TraitOrImplItemRibKind,
889 /// We passed through an item scope. Disallow upvars.
892 /// We're in a constant item. Can't refer to dynamic stuff.
895 /// We passed through a module.
896 ModuleRibKind(Module<'a>),
898 /// We passed through a `macro_rules!` statement
899 MacroDefinition(DefId),
901 /// All bindings in this rib are type parameters that can't be used
902 /// from the default of a type parameter because they're not declared
903 /// before said type parameter. Also see the `visit_generics` override.
904 ForwardTyParamBanRibKind,
909 /// A rib represents a scope names can live in. Note that these appear in many places, not just
910 /// around braces. At any place where the list of accessible names (of the given namespace)
911 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
912 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
915 /// Different [rib kinds](enum.RibKind) are transparent for different names.
917 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
918 /// resolving, the name is looked up from inside out.
921 bindings: FxHashMap<Ident, Def>,
926 fn new(kind: RibKind<'a>) -> Rib<'a> {
928 bindings: FxHashMap(),
934 /// An intermediate resolution result.
936 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
937 /// items are visible in their whole block, while defs only from the place they are defined
939 enum LexicalScopeBinding<'a> {
940 Item(&'a NameBinding<'a>),
944 impl<'a> LexicalScopeBinding<'a> {
945 fn item(self) -> Option<&'a NameBinding<'a>> {
947 LexicalScopeBinding::Item(binding) => Some(binding),
952 fn def(self) -> Def {
954 LexicalScopeBinding::Item(binding) => binding.def(),
955 LexicalScopeBinding::Def(def) => def,
960 #[derive(Copy, Clone, Debug)]
961 pub enum ModuleOrUniformRoot<'a> {
965 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
966 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
967 /// but *not* `extern`), in the Rust 2018 edition.
971 #[derive(Clone, Debug)]
972 enum PathResult<'a> {
973 Module(ModuleOrUniformRoot<'a>),
974 NonModule(PathResolution),
976 Failed(Span, String, bool /* is the error from the last segment? */),
980 /// An anonymous module, eg. just a block.
985 /// { // This is an anonymous module
986 /// f(); // This resolves to (2) as we are inside the block.
989 /// f(); // Resolves to (1)
993 /// Any module with a name.
997 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
998 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1003 /// One node in the tree of modules.
1004 pub struct ModuleData<'a> {
1005 parent: Option<Module<'a>>,
1008 // The def id of the closest normal module (`mod`) ancestor (including this module).
1009 normal_ancestor_id: DefId,
1011 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1012 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, Mark, LegacyScope<'a>, Option<Def>)>>,
1013 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1014 builtin_attrs: RefCell<Vec<(Ident, Mark, LegacyScope<'a>)>>,
1016 // Macro invocations that can expand into items in this module.
1017 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1019 no_implicit_prelude: bool,
1021 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1022 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1024 // Used to memoize the traits in this module for faster searches through all traits in scope.
1025 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1027 // Whether this module is populated. If not populated, any attempt to
1028 // access the children must be preceded with a
1029 // `populate_module_if_necessary` call.
1030 populated: Cell<bool>,
1032 /// Span of the module itself. Used for error reporting.
1038 type Module<'a> = &'a ModuleData<'a>;
1040 impl<'a> ModuleData<'a> {
1041 fn new(parent: Option<Module<'a>>,
1043 normal_ancestor_id: DefId,
1045 span: Span) -> Self {
1050 resolutions: RefCell::new(FxHashMap()),
1051 legacy_macro_resolutions: RefCell::new(Vec::new()),
1052 macro_resolutions: RefCell::new(Vec::new()),
1053 builtin_attrs: RefCell::new(Vec::new()),
1054 unresolved_invocations: RefCell::new(FxHashSet()),
1055 no_implicit_prelude: false,
1056 glob_importers: RefCell::new(Vec::new()),
1057 globs: RefCell::new(Vec::new()),
1058 traits: RefCell::new(None),
1059 populated: Cell::new(normal_ancestor_id.is_local()),
1065 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1066 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1067 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1071 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1072 let resolutions = self.resolutions.borrow();
1073 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1074 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1075 for &(&(ident, ns), &resolution) in resolutions.iter() {
1076 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1080 fn def(&self) -> Option<Def> {
1082 ModuleKind::Def(def, _) => Some(def),
1087 fn def_id(&self) -> Option<DefId> {
1088 self.def().as_ref().map(Def::def_id)
1091 // `self` resolves to the first module ancestor that `is_normal`.
1092 fn is_normal(&self) -> bool {
1094 ModuleKind::Def(Def::Mod(_), _) => true,
1099 fn is_trait(&self) -> bool {
1101 ModuleKind::Def(Def::Trait(_), _) => true,
1106 fn is_local(&self) -> bool {
1107 self.normal_ancestor_id.is_local()
1110 fn nearest_item_scope(&'a self) -> Module<'a> {
1111 if self.is_trait() { self.parent.unwrap() } else { self }
1115 impl<'a> fmt::Debug for ModuleData<'a> {
1116 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1117 write!(f, "{:?}", self.def())
1121 /// Records a possibly-private value, type, or module definition.
1122 #[derive(Clone, Debug)]
1123 pub struct NameBinding<'a> {
1124 kind: NameBindingKind<'a>,
1127 vis: ty::Visibility,
1130 pub trait ToNameBinding<'a> {
1131 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1134 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1135 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1140 #[derive(Clone, Debug)]
1141 enum NameBindingKind<'a> {
1142 Def(Def, /* is_macro_export */ bool),
1145 binding: &'a NameBinding<'a>,
1146 directive: &'a ImportDirective<'a>,
1150 b1: &'a NameBinding<'a>,
1151 b2: &'a NameBinding<'a>,
1155 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1157 struct UseError<'a> {
1158 err: DiagnosticBuilder<'a>,
1159 /// Attach `use` statements for these candidates
1160 candidates: Vec<ImportSuggestion>,
1161 /// The node id of the module to place the use statements in
1163 /// Whether the diagnostic should state that it's "better"
1167 struct AmbiguityError<'a> {
1169 b1: &'a NameBinding<'a>,
1170 b2: &'a NameBinding<'a>,
1173 impl<'a> NameBinding<'a> {
1174 fn module(&self) -> Option<Module<'a>> {
1176 NameBindingKind::Module(module) => Some(module),
1177 NameBindingKind::Import { binding, .. } => binding.module(),
1182 fn def(&self) -> Def {
1184 NameBindingKind::Def(def, _) => def,
1185 NameBindingKind::Module(module) => module.def().unwrap(),
1186 NameBindingKind::Import { binding, .. } => binding.def(),
1187 NameBindingKind::Ambiguity { .. } => Def::Err,
1191 fn def_ignoring_ambiguity(&self) -> Def {
1193 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1194 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1199 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1200 resolver.get_macro(self.def_ignoring_ambiguity())
1203 // We sometimes need to treat variants as `pub` for backwards compatibility
1204 fn pseudo_vis(&self) -> ty::Visibility {
1205 if self.is_variant() && self.def().def_id().is_local() {
1206 ty::Visibility::Public
1212 fn is_variant(&self) -> bool {
1214 NameBindingKind::Def(Def::Variant(..), _) |
1215 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1220 fn is_extern_crate(&self) -> bool {
1222 NameBindingKind::Import {
1223 directive: &ImportDirective {
1224 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1231 fn is_import(&self) -> bool {
1233 NameBindingKind::Import { .. } => true,
1238 fn is_renamed_extern_crate(&self) -> bool {
1239 if let NameBindingKind::Import { directive, ..} = self.kind {
1240 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1247 fn is_glob_import(&self) -> bool {
1249 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1250 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1255 fn is_importable(&self) -> bool {
1257 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1262 fn is_macro_def(&self) -> bool {
1264 NameBindingKind::Def(Def::Macro(..), _) => true,
1269 fn macro_kind(&self) -> Option<MacroKind> {
1270 match self.def_ignoring_ambiguity() {
1271 Def::Macro(_, kind) => Some(kind),
1272 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1277 fn descr(&self) -> &'static str {
1278 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1281 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1282 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1283 // Then this function returns `true` if `self` may emerge from a macro *after* that
1284 // in some later round and screw up our previously found resolution.
1285 // See more detailed explanation in
1286 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1287 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1288 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1289 // Expansions are partially ordered, so "may appear after" is an inversion of
1290 // "certainly appears before or simultaneously" and includes unordered cases.
1291 let self_parent_expansion = self.expansion;
1292 let other_parent_expansion = binding.expansion;
1293 let certainly_before_other_or_simultaneously =
1294 other_parent_expansion.is_descendant_of(self_parent_expansion);
1295 let certainly_before_invoc_or_simultaneously =
1296 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1297 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1301 /// Interns the names of the primitive types.
1303 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1304 /// special handling, since they have no place of origin.
1305 struct PrimitiveTypeTable {
1306 primitive_types: FxHashMap<Name, PrimTy>,
1309 impl PrimitiveTypeTable {
1310 fn new() -> PrimitiveTypeTable {
1311 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1313 table.intern("bool", Bool);
1314 table.intern("char", Char);
1315 table.intern("f32", Float(FloatTy::F32));
1316 table.intern("f64", Float(FloatTy::F64));
1317 table.intern("isize", Int(IntTy::Isize));
1318 table.intern("i8", Int(IntTy::I8));
1319 table.intern("i16", Int(IntTy::I16));
1320 table.intern("i32", Int(IntTy::I32));
1321 table.intern("i64", Int(IntTy::I64));
1322 table.intern("i128", Int(IntTy::I128));
1323 table.intern("str", Str);
1324 table.intern("usize", Uint(UintTy::Usize));
1325 table.intern("u8", Uint(UintTy::U8));
1326 table.intern("u16", Uint(UintTy::U16));
1327 table.intern("u32", Uint(UintTy::U32));
1328 table.intern("u64", Uint(UintTy::U64));
1329 table.intern("u128", Uint(UintTy::U128));
1333 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1334 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1338 /// The main resolver class.
1340 /// This is the visitor that walks the whole crate.
1341 pub struct Resolver<'a, 'b: 'a> {
1342 session: &'a Session,
1345 pub definitions: Definitions,
1347 graph_root: Module<'a>,
1349 prelude: Option<Module<'a>>,
1350 extern_prelude: FxHashSet<Name>,
1352 /// n.b. This is used only for better diagnostics, not name resolution itself.
1353 has_self: FxHashSet<DefId>,
1355 /// Names of fields of an item `DefId` accessible with dot syntax.
1356 /// Used for hints during error reporting.
1357 field_names: FxHashMap<DefId, Vec<Name>>,
1359 /// All imports known to succeed or fail.
1360 determined_imports: Vec<&'a ImportDirective<'a>>,
1362 /// All non-determined imports.
1363 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1365 /// The module that represents the current item scope.
1366 current_module: Module<'a>,
1368 /// The current set of local scopes for types and values.
1369 /// FIXME #4948: Reuse ribs to avoid allocation.
1370 ribs: PerNS<Vec<Rib<'a>>>,
1372 /// The current set of local scopes, for labels.
1373 label_ribs: Vec<Rib<'a>>,
1375 /// The trait that the current context can refer to.
1376 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1378 /// The current self type if inside an impl (used for better errors).
1379 current_self_type: Option<Ty>,
1381 /// The idents for the primitive types.
1382 primitive_type_table: PrimitiveTypeTable,
1385 import_map: ImportMap,
1386 pub freevars: FreevarMap,
1387 freevars_seen: NodeMap<NodeMap<usize>>,
1388 pub export_map: ExportMap,
1389 pub trait_map: TraitMap,
1391 /// A map from nodes to anonymous modules.
1392 /// Anonymous modules are pseudo-modules that are implicitly created around items
1393 /// contained within blocks.
1395 /// For example, if we have this:
1403 /// There will be an anonymous module created around `g` with the ID of the
1404 /// entry block for `f`.
1405 block_map: NodeMap<Module<'a>>,
1406 module_map: FxHashMap<DefId, Module<'a>>,
1407 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1409 pub make_glob_map: bool,
1410 /// Maps imports to the names of items actually imported (this actually maps
1411 /// all imports, but only glob imports are actually interesting).
1412 pub glob_map: GlobMap,
1414 used_imports: FxHashSet<(NodeId, Namespace)>,
1415 pub maybe_unused_trait_imports: NodeSet,
1416 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1418 /// A list of labels as of yet unused. Labels will be removed from this map when
1419 /// they are used (in a `break` or `continue` statement)
1420 pub unused_labels: FxHashMap<NodeId, Span>,
1422 /// privacy errors are delayed until the end in order to deduplicate them
1423 privacy_errors: Vec<PrivacyError<'a>>,
1424 /// ambiguity errors are delayed for deduplication
1425 ambiguity_errors: Vec<AmbiguityError<'a>>,
1426 /// `use` injections are delayed for better placement and deduplication
1427 use_injections: Vec<UseError<'a>>,
1428 /// `use` injections for proc macros wrongly imported with #[macro_use]
1429 proc_mac_errors: Vec<macros::ProcMacError>,
1430 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1431 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1433 arenas: &'a ResolverArenas<'a>,
1434 dummy_binding: &'a NameBinding<'a>,
1436 crate_loader: &'a mut CrateLoader<'b>,
1437 macro_names: FxHashSet<Ident>,
1438 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1439 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1440 pub all_macros: FxHashMap<Name, Def>,
1441 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1442 macro_defs: FxHashMap<Mark, DefId>,
1443 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1444 pub whitelisted_legacy_custom_derives: Vec<Name>,
1445 pub found_unresolved_macro: bool,
1447 /// List of crate local macros that we need to warn about as being unused.
1448 /// Right now this only includes macro_rules! macros, and macros 2.0.
1449 unused_macros: FxHashSet<DefId>,
1451 /// Maps the `Mark` of an expansion to its containing module or block.
1452 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1454 /// Avoid duplicated errors for "name already defined".
1455 name_already_seen: FxHashMap<Name, Span>,
1457 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1458 warned_proc_macros: FxHashSet<Name>,
1460 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1462 /// This table maps struct IDs into struct constructor IDs,
1463 /// it's not used during normal resolution, only for better error reporting.
1464 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1466 /// Map from tuple struct's DefId to VariantData's Def
1467 tuple_structs: DefIdMap<Def>,
1469 /// Only used for better errors on `fn(): fn()`
1470 current_type_ascription: Vec<Span>,
1472 injected_crate: Option<Module<'a>>,
1474 /// Only supposed to be used by rustdoc, otherwise should be false.
1475 pub ignore_extern_prelude_feature: bool,
1478 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1479 pub struct ResolverArenas<'a> {
1480 modules: arena::TypedArena<ModuleData<'a>>,
1481 local_modules: RefCell<Vec<Module<'a>>>,
1482 name_bindings: arena::TypedArena<NameBinding<'a>>,
1483 import_directives: arena::TypedArena<ImportDirective<'a>>,
1484 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1485 invocation_data: arena::TypedArena<InvocationData<'a>>,
1486 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1489 impl<'a> ResolverArenas<'a> {
1490 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1491 let module = self.modules.alloc(module);
1492 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1493 self.local_modules.borrow_mut().push(module);
1497 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1498 self.local_modules.borrow()
1500 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1501 self.name_bindings.alloc(name_binding)
1503 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1504 -> &'a ImportDirective {
1505 self.import_directives.alloc(import_directive)
1507 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1508 self.name_resolutions.alloc(Default::default())
1510 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1511 -> &'a InvocationData<'a> {
1512 self.invocation_data.alloc(expansion_data)
1514 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1515 self.legacy_bindings.alloc(binding)
1519 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1520 fn parent(self, id: DefId) -> Option<DefId> {
1522 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1523 _ => self.cstore.def_key(id).parent,
1524 }.map(|index| DefId { index, ..id })
1528 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1529 /// the resolver is no longer needed as all the relevant information is inline.
1530 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1531 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1532 self.resolve_hir_path_cb(path, is_value,
1533 |resolver, span, error| resolve_error(resolver, span, error))
1536 fn resolve_str_path(
1539 crate_root: Option<&str>,
1540 components: &[&str],
1541 args: Option<P<hir::GenericArgs>>,
1544 let mut segments = iter::once(keywords::CrateRoot.ident())
1546 crate_root.into_iter()
1547 .chain(components.iter().cloned())
1548 .map(Ident::from_str)
1549 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1551 if let Some(args) = args {
1552 let ident = segments.last().unwrap().ident;
1553 *segments.last_mut().unwrap() = hir::PathSegment {
1560 let mut path = hir::Path {
1563 segments: segments.into(),
1566 self.resolve_hir_path(&mut path, is_value);
1570 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1571 self.def_map.get(&id).cloned()
1574 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1575 self.import_map.get(&id).cloned().unwrap_or_default()
1578 fn definitions(&mut self) -> &mut Definitions {
1579 &mut self.definitions
1583 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1584 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1585 /// isn't something that can be returned because it can't be made to live that long,
1586 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1587 /// just that an error occurred.
1588 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1589 -> Result<hir::Path, ()> {
1591 let mut errored = false;
1593 let mut path = if path_str.starts_with("::") {
1597 segments: iter::once(keywords::CrateRoot.ident()).chain({
1598 path_str.split("::").skip(1).map(Ident::from_str)
1599 }).map(hir::PathSegment::from_ident).collect(),
1605 segments: path_str.split("::").map(Ident::from_str)
1606 .map(hir::PathSegment::from_ident).collect(),
1609 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1610 if errored || path.def == Def::Err {
1617 /// resolve_hir_path, but takes a callback in case there was an error
1618 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1619 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1621 let namespace = if is_value { ValueNS } else { TypeNS };
1622 let hir::Path { ref segments, span, ref mut def } = *path;
1623 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1624 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1625 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1626 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1627 *def = module.def().unwrap(),
1628 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1629 *def = path_res.base_def(),
1630 PathResult::NonModule(..) => match self.resolve_path(
1638 PathResult::Failed(span, msg, _) => {
1639 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1643 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1644 PathResult::Indeterminate => unreachable!(),
1645 PathResult::Failed(span, msg, _) => {
1646 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1652 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1653 pub fn new(session: &'a Session,
1657 make_glob_map: MakeGlobMap,
1658 crate_loader: &'a mut CrateLoader<'crateloader>,
1659 arenas: &'a ResolverArenas<'a>)
1660 -> Resolver<'a, 'crateloader> {
1661 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1662 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1663 let graph_root = arenas.alloc_module(ModuleData {
1664 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1665 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1667 let mut module_map = FxHashMap();
1668 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1670 let mut definitions = Definitions::new();
1671 DefCollector::new(&mut definitions, Mark::root())
1672 .collect_root(crate_name, session.local_crate_disambiguator());
1674 let mut extern_prelude: FxHashSet<Name> =
1675 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1676 if !attr::contains_name(&krate.attrs, "no_core") {
1677 if !attr::contains_name(&krate.attrs, "no_std") {
1678 extern_prelude.insert(Symbol::intern("std"));
1680 extern_prelude.insert(Symbol::intern("core"));
1684 let mut invocations = FxHashMap();
1685 invocations.insert(Mark::root(),
1686 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1688 let mut macro_defs = FxHashMap();
1689 macro_defs.insert(Mark::root(), root_def_id);
1698 // The outermost module has def ID 0; this is not reflected in the
1704 has_self: FxHashSet(),
1705 field_names: FxHashMap(),
1707 determined_imports: Vec::new(),
1708 indeterminate_imports: Vec::new(),
1710 current_module: graph_root,
1712 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1713 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1714 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1716 label_ribs: Vec::new(),
1718 current_trait_ref: None,
1719 current_self_type: None,
1721 primitive_type_table: PrimitiveTypeTable::new(),
1724 import_map: NodeMap(),
1725 freevars: NodeMap(),
1726 freevars_seen: NodeMap(),
1727 export_map: FxHashMap(),
1728 trait_map: NodeMap(),
1730 block_map: NodeMap(),
1731 extern_module_map: FxHashMap(),
1733 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1734 glob_map: NodeMap(),
1736 used_imports: FxHashSet(),
1737 maybe_unused_trait_imports: NodeSet(),
1738 maybe_unused_extern_crates: Vec::new(),
1740 unused_labels: FxHashMap(),
1742 privacy_errors: Vec::new(),
1743 ambiguity_errors: Vec::new(),
1744 use_injections: Vec::new(),
1745 proc_mac_errors: Vec::new(),
1746 macro_expanded_macro_export_errors: BTreeSet::new(),
1749 dummy_binding: arenas.alloc_name_binding(NameBinding {
1750 kind: NameBindingKind::Def(Def::Err, false),
1751 expansion: Mark::root(),
1753 vis: ty::Visibility::Public,
1757 macro_names: FxHashSet(),
1758 builtin_macros: FxHashMap(),
1759 macro_use_prelude: FxHashMap(),
1760 all_macros: FxHashMap(),
1761 macro_map: FxHashMap(),
1764 local_macro_def_scopes: FxHashMap(),
1765 name_already_seen: FxHashMap(),
1766 whitelisted_legacy_custom_derives: Vec::new(),
1767 warned_proc_macros: FxHashSet(),
1768 potentially_unused_imports: Vec::new(),
1769 struct_constructors: DefIdMap(),
1770 tuple_structs: DefIdMap(),
1771 found_unresolved_macro: false,
1772 unused_macros: FxHashSet(),
1773 current_type_ascription: Vec::new(),
1774 injected_crate: None,
1775 ignore_extern_prelude_feature: false,
1779 pub fn arenas() -> ResolverArenas<'a> {
1781 modules: arena::TypedArena::new(),
1782 local_modules: RefCell::new(Vec::new()),
1783 name_bindings: arena::TypedArena::new(),
1784 import_directives: arena::TypedArena::new(),
1785 name_resolutions: arena::TypedArena::new(),
1786 invocation_data: arena::TypedArena::new(),
1787 legacy_bindings: arena::TypedArena::new(),
1791 /// Runs the function on each namespace.
1792 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1798 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1800 match self.macro_defs.get(&ctxt.outer()) {
1801 Some(&def_id) => return def_id,
1802 None => ctxt.remove_mark(),
1807 /// Entry point to crate resolution.
1808 pub fn resolve_crate(&mut self, krate: &Crate) {
1809 ImportResolver { resolver: self }.finalize_imports();
1810 self.current_module = self.graph_root;
1811 self.finalize_current_module_macro_resolutions();
1813 visit::walk_crate(self, krate);
1815 check_unused::check_crate(self, krate);
1816 self.report_errors(krate);
1817 self.crate_loader.postprocess(krate);
1824 normal_ancestor_id: DefId,
1828 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1829 self.arenas.alloc_module(module)
1832 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1833 -> bool /* true if an error was reported */ {
1834 match binding.kind {
1835 NameBindingKind::Import { directive, binding, ref used }
1838 directive.used.set(true);
1839 self.used_imports.insert((directive.id, ns));
1840 self.add_to_glob_map(directive.id, ident);
1841 self.record_use(ident, ns, binding)
1843 NameBindingKind::Import { .. } => false,
1844 NameBindingKind::Ambiguity { b1, b2 } => {
1845 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1852 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1853 if self.make_glob_map {
1854 self.glob_map.entry(id).or_default().insert(ident.name);
1858 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1859 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1860 /// `ident` in the first scope that defines it (or None if no scopes define it).
1862 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1863 /// the items are defined in the block. For example,
1866 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1869 /// g(); // This resolves to the local variable `g` since it shadows the item.
1873 /// Invariant: This must only be called during main resolution, not during
1874 /// import resolution.
1875 fn resolve_ident_in_lexical_scope(&mut self,
1878 record_used_id: Option<NodeId>,
1880 -> Option<LexicalScopeBinding<'a>> {
1881 let record_used = record_used_id.is_some();
1882 assert!(ns == TypeNS || ns == ValueNS);
1884 ident.span = if ident.name == keywords::SelfType.name() {
1885 // FIXME(jseyfried) improve `Self` hygiene
1886 ident.span.with_ctxt(SyntaxContext::empty())
1891 ident = ident.modern_and_legacy();
1894 // Walk backwards up the ribs in scope.
1895 let mut module = self.graph_root;
1896 for i in (0 .. self.ribs[ns].len()).rev() {
1897 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1898 // The ident resolves to a type parameter or local variable.
1899 return Some(LexicalScopeBinding::Def(
1900 self.adjust_local_def(ns, i, def, record_used, path_span)
1904 module = match self.ribs[ns][i].kind {
1905 ModuleRibKind(module) => module,
1906 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1907 // If an invocation of this macro created `ident`, give up on `ident`
1908 // and switch to `ident`'s source from the macro definition.
1909 ident.span.remove_mark();
1915 let item = self.resolve_ident_in_module_unadjusted(
1916 ModuleOrUniformRoot::Module(module),
1923 if let Ok(binding) = item {
1924 // The ident resolves to an item.
1925 return Some(LexicalScopeBinding::Item(binding));
1929 ModuleKind::Block(..) => {}, // We can see through blocks
1934 ident.span = ident.span.modern();
1935 let mut poisoned = None;
1937 let opt_module = if let Some(node_id) = record_used_id {
1938 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1939 node_id, &mut poisoned)
1941 self.hygienic_lexical_parent(module, &mut ident.span)
1943 module = unwrap_or!(opt_module, break);
1944 let orig_current_module = self.current_module;
1945 self.current_module = module; // Lexical resolutions can never be a privacy error.
1946 let result = self.resolve_ident_in_module_unadjusted(
1947 ModuleOrUniformRoot::Module(module),
1954 self.current_module = orig_current_module;
1958 if let Some(node_id) = poisoned {
1959 self.session.buffer_lint_with_diagnostic(
1960 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1961 node_id, ident.span,
1962 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1963 lint::builtin::BuiltinLintDiagnostics::
1964 ProcMacroDeriveResolutionFallback(ident.span),
1967 return Some(LexicalScopeBinding::Item(binding))
1969 Err(Determined) => continue,
1970 Err(Undetermined) =>
1971 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1975 if !module.no_implicit_prelude {
1976 // `record_used` means that we don't try to load crates during speculative resolution
1977 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1978 if !self.session.features_untracked().extern_prelude &&
1979 !self.ignore_extern_prelude_feature {
1980 feature_err(&self.session.parse_sess, "extern_prelude",
1981 ident.span, GateIssue::Language,
1982 "access to extern crates through prelude is experimental").emit();
1985 let crate_root = self.load_extern_prelude_crate_if_needed(ident);
1987 let binding = (crate_root, ty::Visibility::Public,
1988 ident.span, Mark::root()).to_name_binding(self.arenas);
1989 return Some(LexicalScopeBinding::Item(binding));
1991 if ns == TypeNS && is_known_tool(ident.name) {
1992 let binding = (Def::ToolMod, ty::Visibility::Public,
1993 ident.span, Mark::root()).to_name_binding(self.arenas);
1994 return Some(LexicalScopeBinding::Item(binding));
1996 if let Some(prelude) = self.prelude {
1997 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1998 ModuleOrUniformRoot::Module(prelude),
2005 return Some(LexicalScopeBinding::Item(binding));
2013 fn load_extern_prelude_crate_if_needed(&mut self, ident: Ident) -> Module<'a> {
2014 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
2015 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2016 self.populate_module_if_necessary(&crate_root);
2020 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2021 -> Option<Module<'a>> {
2022 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2023 return Some(self.macro_def_scope(span.remove_mark()));
2026 if let ModuleKind::Block(..) = module.kind {
2027 return Some(module.parent.unwrap());
2033 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2034 span: &mut Span, node_id: NodeId,
2035 poisoned: &mut Option<NodeId>)
2036 -> Option<Module<'a>> {
2037 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2041 // We need to support the next case under a deprecation warning
2044 // ---- begin: this comes from a proc macro derive
2045 // mod implementation_details {
2046 // // Note that `MyStruct` is not in scope here.
2047 // impl SomeTrait for MyStruct { ... }
2051 // So we have to fall back to the module's parent during lexical resolution in this case.
2052 if let Some(parent) = module.parent {
2053 // Inner module is inside the macro, parent module is outside of the macro.
2054 if module.expansion != parent.expansion &&
2055 module.expansion.is_descendant_of(parent.expansion) {
2056 // The macro is a proc macro derive
2057 if module.expansion.looks_like_proc_macro_derive() {
2058 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2059 *poisoned = Some(node_id);
2060 return module.parent;
2069 fn resolve_ident_in_module(&mut self,
2070 module: ModuleOrUniformRoot<'a>,
2075 -> Result<&'a NameBinding<'a>, Determinacy> {
2076 ident.span = ident.span.modern();
2077 let orig_current_module = self.current_module;
2078 if let ModuleOrUniformRoot::Module(module) = module {
2079 if let Some(def) = ident.span.adjust(module.expansion) {
2080 self.current_module = self.macro_def_scope(def);
2083 let result = self.resolve_ident_in_module_unadjusted(
2084 module, ident, ns, false, record_used, span,
2086 self.current_module = orig_current_module;
2090 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2091 let mut ctxt = ident.span.ctxt();
2092 let mark = if ident.name == keywords::DollarCrate.name() {
2093 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2094 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2095 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2096 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2097 // definitions actually produced by `macro` and `macro` definitions produced by
2098 // `macro_rules!`, but at least such configurations are not stable yet.
2099 ctxt = ctxt.modern_and_legacy();
2100 let mut iter = ctxt.marks().into_iter().rev().peekable();
2101 let mut result = None;
2102 // Find the last modern mark from the end if it exists.
2103 while let Some(&(mark, transparency)) = iter.peek() {
2104 if transparency == Transparency::Opaque {
2105 result = Some(mark);
2111 // Then find the last legacy mark from the end if it exists.
2112 for (mark, transparency) in iter {
2113 if transparency == Transparency::SemiTransparent {
2114 result = Some(mark);
2121 ctxt = ctxt.modern();
2122 ctxt.adjust(Mark::root())
2124 let module = match mark {
2125 Some(def) => self.macro_def_scope(def),
2126 None => return self.graph_root,
2128 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2131 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2132 let mut module = self.get_module(module.normal_ancestor_id);
2133 while module.span.ctxt().modern() != *ctxt {
2134 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2135 module = self.get_module(parent.normal_ancestor_id);
2142 // We maintain a list of value ribs and type ribs.
2144 // Simultaneously, we keep track of the current position in the module
2145 // graph in the `current_module` pointer. When we go to resolve a name in
2146 // the value or type namespaces, we first look through all the ribs and
2147 // then query the module graph. When we resolve a name in the module
2148 // namespace, we can skip all the ribs (since nested modules are not
2149 // allowed within blocks in Rust) and jump straight to the current module
2152 // Named implementations are handled separately. When we find a method
2153 // call, we consult the module node to find all of the implementations in
2154 // scope. This information is lazily cached in the module node. We then
2155 // generate a fake "implementation scope" containing all the
2156 // implementations thus found, for compatibility with old resolve pass.
2158 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2159 where F: FnOnce(&mut Resolver) -> T
2161 let id = self.definitions.local_def_id(id);
2162 let module = self.module_map.get(&id).cloned(); // clones a reference
2163 if let Some(module) = module {
2164 // Move down in the graph.
2165 let orig_module = replace(&mut self.current_module, module);
2166 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2167 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2169 self.finalize_current_module_macro_resolutions();
2172 self.current_module = orig_module;
2173 self.ribs[ValueNS].pop();
2174 self.ribs[TypeNS].pop();
2181 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2182 /// is returned by the given predicate function
2184 /// Stops after meeting a closure.
2185 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2186 where P: Fn(&Rib, Ident) -> Option<R>
2188 for rib in self.label_ribs.iter().rev() {
2191 // If an invocation of this macro created `ident`, give up on `ident`
2192 // and switch to `ident`'s source from the macro definition.
2193 MacroDefinition(def) => {
2194 if def == self.macro_def(ident.span.ctxt()) {
2195 ident.span.remove_mark();
2199 // Do not resolve labels across function boundary
2203 let r = pred(rib, ident);
2211 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2212 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2213 let item_def_id = this.definitions.local_def_id(item.id);
2214 if this.session.features_untracked().self_in_typedefs {
2215 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2216 visit::walk_item(this, item);
2219 visit::walk_item(this, item);
2224 fn resolve_item(&mut self, item: &Item) {
2225 let name = item.ident.name;
2226 debug!("(resolving item) resolving {}", name);
2229 ItemKind::Ty(_, ref generics) |
2230 ItemKind::Fn(_, _, ref generics, _) |
2231 ItemKind::Existential(_, ref generics) => {
2232 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2233 |this| visit::walk_item(this, item));
2236 ItemKind::Struct(ref variant, ref generics) => {
2237 if variant.is_tuple() || variant.is_unit() {
2238 if let Some(def_id) = self.definitions.opt_local_def_id(item.id) {
2239 if let Some(variant_id) = self.definitions.opt_local_def_id(variant.id()) {
2240 let variant_def = if variant.is_tuple() {
2241 Def::StructCtor(variant_id, CtorKind::Fn)
2243 Def::StructCtor(variant_id, CtorKind::Const)
2245 self.tuple_structs.insert(def_id, variant_def);
2249 self.resolve_adt(item, generics);
2252 ItemKind::Enum(_, ref generics) |
2253 ItemKind::Union(_, ref generics) => {
2254 self.resolve_adt(item, generics);
2257 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2258 self.resolve_implementation(generics,
2264 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2265 // Create a new rib for the trait-wide type parameters.
2266 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2267 let local_def_id = this.definitions.local_def_id(item.id);
2268 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2269 this.visit_generics(generics);
2270 walk_list!(this, visit_param_bound, bounds);
2272 for trait_item in trait_items {
2273 let type_parameters = HasTypeParameters(&trait_item.generics,
2274 TraitOrImplItemRibKind);
2275 this.with_type_parameter_rib(type_parameters, |this| {
2276 match trait_item.node {
2277 TraitItemKind::Const(ref ty, ref default) => {
2280 // Only impose the restrictions of
2281 // ConstRibKind for an actual constant
2282 // expression in a provided default.
2283 if let Some(ref expr) = *default{
2284 this.with_constant_rib(|this| {
2285 this.visit_expr(expr);
2289 TraitItemKind::Method(_, _) => {
2290 visit::walk_trait_item(this, trait_item)
2292 TraitItemKind::Type(..) => {
2293 visit::walk_trait_item(this, trait_item)
2295 TraitItemKind::Macro(_) => {
2296 panic!("unexpanded macro in resolve!")
2305 ItemKind::TraitAlias(ref generics, ref bounds) => {
2306 // Create a new rib for the trait-wide type parameters.
2307 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2308 let local_def_id = this.definitions.local_def_id(item.id);
2309 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2310 this.visit_generics(generics);
2311 walk_list!(this, visit_param_bound, bounds);
2316 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2317 self.with_scope(item.id, |this| {
2318 visit::walk_item(this, item);
2322 ItemKind::Static(ref ty, _, ref expr) |
2323 ItemKind::Const(ref ty, ref expr) => {
2324 self.with_item_rib(|this| {
2326 this.with_constant_rib(|this| {
2327 this.visit_expr(expr);
2332 ItemKind::Use(ref use_tree) => {
2333 // Imports are resolved as global by default, add starting root segment.
2335 segments: use_tree.prefix.make_root().into_iter().collect(),
2336 span: use_tree.span,
2338 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2341 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2342 // do nothing, these are just around to be encoded
2345 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2349 /// For the most part, use trees are desugared into `ImportDirective` instances
2350 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2351 /// there is one special case we handle here: an empty nested import like
2352 /// `a::{b::{}}`, which desugares into...no import directives.
2353 fn resolve_use_tree(
2358 use_tree: &ast::UseTree,
2361 match use_tree.kind {
2362 ast::UseTreeKind::Nested(ref items) => {
2364 segments: prefix.segments
2366 .chain(use_tree.prefix.segments.iter())
2369 span: prefix.span.to(use_tree.prefix.span),
2372 if items.len() == 0 {
2373 // Resolve prefix of an import with empty braces (issue #28388).
2374 self.smart_resolve_path_with_crate_lint(
2378 PathSource::ImportPrefix,
2379 CrateLint::UsePath { root_id, root_span },
2382 for &(ref tree, nested_id) in items {
2383 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2387 ast::UseTreeKind::Simple(..) => {},
2388 ast::UseTreeKind::Glob => {},
2392 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2393 where F: FnOnce(&mut Resolver)
2395 match type_parameters {
2396 HasTypeParameters(generics, rib_kind) => {
2397 let mut function_type_rib = Rib::new(rib_kind);
2398 let mut seen_bindings = FxHashMap();
2399 for param in &generics.params {
2401 GenericParamKind::Lifetime { .. } => {}
2402 GenericParamKind::Type { .. } => {
2403 let ident = param.ident.modern();
2404 debug!("with_type_parameter_rib: {}", param.id);
2406 if seen_bindings.contains_key(&ident) {
2407 let span = seen_bindings.get(&ident).unwrap();
2408 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2412 resolve_error(self, param.ident.span, err);
2414 seen_bindings.entry(ident).or_insert(param.ident.span);
2416 // Plain insert (no renaming).
2417 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2418 function_type_rib.bindings.insert(ident, def);
2419 self.record_def(param.id, PathResolution::new(def));
2423 self.ribs[TypeNS].push(function_type_rib);
2426 NoTypeParameters => {
2433 if let HasTypeParameters(..) = type_parameters {
2434 self.ribs[TypeNS].pop();
2438 fn with_label_rib<F>(&mut self, f: F)
2439 where F: FnOnce(&mut Resolver)
2441 self.label_ribs.push(Rib::new(NormalRibKind));
2443 self.label_ribs.pop();
2446 fn with_item_rib<F>(&mut self, f: F)
2447 where F: FnOnce(&mut Resolver)
2449 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2450 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2452 self.ribs[TypeNS].pop();
2453 self.ribs[ValueNS].pop();
2456 fn with_constant_rib<F>(&mut self, f: F)
2457 where F: FnOnce(&mut Resolver)
2459 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2460 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2462 self.label_ribs.pop();
2463 self.ribs[ValueNS].pop();
2466 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2467 where F: FnOnce(&mut Resolver) -> T
2469 // Handle nested impls (inside fn bodies)
2470 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2471 let result = f(self);
2472 self.current_self_type = previous_value;
2476 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2477 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2478 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2480 let mut new_val = None;
2481 let mut new_id = None;
2482 if let Some(trait_ref) = opt_trait_ref {
2483 let path: Vec<_> = trait_ref.path.segments.iter()
2484 .map(|seg| seg.ident)
2486 let def = self.smart_resolve_path_fragment(
2490 trait_ref.path.span,
2491 PathSource::Trait(AliasPossibility::No),
2492 CrateLint::SimplePath(trait_ref.ref_id),
2494 if def != Def::Err {
2495 new_id = Some(def.def_id());
2496 let span = trait_ref.path.span;
2497 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2504 CrateLint::SimplePath(trait_ref.ref_id),
2507 new_val = Some((module, trait_ref.clone()));
2511 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2512 let result = f(self, new_id);
2513 self.current_trait_ref = original_trait_ref;
2517 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2518 where F: FnOnce(&mut Resolver)
2520 let mut self_type_rib = Rib::new(NormalRibKind);
2522 // plain insert (no renaming, types are not currently hygienic....)
2523 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2524 self.ribs[TypeNS].push(self_type_rib);
2526 self.ribs[TypeNS].pop();
2529 fn with_tuple_struct_self_ctor_rib<F>(&mut self, self_ty: &Ty, f: F)
2530 where F: FnOnce(&mut Resolver)
2532 let variant_def = if self.session.features_untracked().tuple_struct_self_ctor {
2533 let base_def = self.def_map.get(&self_ty.id).map(|r| r.base_def());
2534 if let Some(Def::Struct(ref def_id)) = base_def {
2535 self.tuple_structs.get(def_id).cloned()
2543 // when feature gate is enabled and `Self` is a tuple struct
2544 if let Some(variant_def) = variant_def {
2545 let mut self_type_rib = Rib::new(NormalRibKind);
2546 self_type_rib.bindings.insert(keywords::SelfType.ident(), variant_def);
2547 self.ribs[ValueNS].push(self_type_rib);
2549 self.ribs[ValueNS].pop();
2555 fn resolve_implementation(&mut self,
2556 generics: &Generics,
2557 opt_trait_reference: &Option<TraitRef>,
2560 impl_items: &[ImplItem]) {
2561 // If applicable, create a rib for the type parameters.
2562 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2563 // Dummy self type for better errors if `Self` is used in the trait path.
2564 this.with_self_rib(Def::SelfTy(None, None), |this| {
2565 // Resolve the trait reference, if necessary.
2566 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2567 let item_def_id = this.definitions.local_def_id(item_id);
2568 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2569 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2570 // Resolve type arguments in the trait path.
2571 visit::walk_trait_ref(this, trait_ref);
2573 // Resolve the self type.
2574 this.visit_ty(self_type);
2575 // Resolve the type parameters.
2576 this.visit_generics(generics);
2577 // Resolve the items within the impl.
2578 this.with_current_self_type(self_type, |this| {
2579 for impl_item in impl_items {
2580 this.resolve_visibility(&impl_item.vis);
2582 // We also need a new scope for the impl item type parameters.
2583 let type_parameters = HasTypeParameters(&impl_item.generics,
2584 TraitOrImplItemRibKind);
2585 this.with_type_parameter_rib(type_parameters, |this| {
2586 use self::ResolutionError::*;
2587 match impl_item.node {
2588 ImplItemKind::Const(..) => {
2589 // If this is a trait impl, ensure the const
2591 this.check_trait_item(impl_item.ident,
2594 |n, s| ConstNotMemberOfTrait(n, s));
2595 this.with_constant_rib(|this|
2596 visit::walk_impl_item(this, impl_item)
2599 ImplItemKind::Method(..) => {
2600 // If this is a trait impl, ensure the method
2602 this.check_trait_item(impl_item.ident,
2605 |n, s| MethodNotMemberOfTrait(n, s));
2606 this.with_tuple_struct_self_ctor_rib(self_type, |this| {
2607 visit::walk_impl_item(this, impl_item);
2610 ImplItemKind::Type(ref ty) => {
2611 // If this is a trait impl, ensure the type
2613 this.check_trait_item(impl_item.ident,
2616 |n, s| TypeNotMemberOfTrait(n, s));
2620 ImplItemKind::Existential(ref bounds) => {
2621 // If this is a trait impl, ensure the type
2623 this.check_trait_item(impl_item.ident,
2626 |n, s| TypeNotMemberOfTrait(n, s));
2628 for bound in bounds {
2629 this.visit_param_bound(bound);
2632 ImplItemKind::Macro(_) =>
2633 panic!("unexpanded macro in resolve!"),
2644 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2645 where F: FnOnce(Name, &str) -> ResolutionError
2647 // If there is a TraitRef in scope for an impl, then the method must be in the
2649 if let Some((module, _)) = self.current_trait_ref {
2650 if self.resolve_ident_in_module(
2651 ModuleOrUniformRoot::Module(module),
2657 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2658 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2663 fn resolve_local(&mut self, local: &Local) {
2664 // Resolve the type.
2665 walk_list!(self, visit_ty, &local.ty);
2667 // Resolve the initializer.
2668 walk_list!(self, visit_expr, &local.init);
2670 // Resolve the pattern.
2671 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2674 // build a map from pattern identifiers to binding-info's.
2675 // this is done hygienically. This could arise for a macro
2676 // that expands into an or-pattern where one 'x' was from the
2677 // user and one 'x' came from the macro.
2678 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2679 let mut binding_map = FxHashMap();
2681 pat.walk(&mut |pat| {
2682 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2683 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2684 Some(Def::Local(..)) => true,
2687 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2688 binding_map.insert(ident, binding_info);
2697 // check that all of the arms in an or-pattern have exactly the
2698 // same set of bindings, with the same binding modes for each.
2699 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2700 if pats.is_empty() {
2704 let mut missing_vars = FxHashMap();
2705 let mut inconsistent_vars = FxHashMap();
2706 for (i, p) in pats.iter().enumerate() {
2707 let map_i = self.binding_mode_map(&p);
2709 for (j, q) in pats.iter().enumerate() {
2714 let map_j = self.binding_mode_map(&q);
2715 for (&key, &binding_i) in &map_i {
2716 if map_j.len() == 0 { // Account for missing bindings when
2717 let binding_error = missing_vars // map_j has none.
2719 .or_insert(BindingError {
2721 origin: BTreeSet::new(),
2722 target: BTreeSet::new(),
2724 binding_error.origin.insert(binding_i.span);
2725 binding_error.target.insert(q.span);
2727 for (&key_j, &binding_j) in &map_j {
2728 match map_i.get(&key_j) {
2729 None => { // missing binding
2730 let binding_error = missing_vars
2732 .or_insert(BindingError {
2734 origin: BTreeSet::new(),
2735 target: BTreeSet::new(),
2737 binding_error.origin.insert(binding_j.span);
2738 binding_error.target.insert(p.span);
2740 Some(binding_i) => { // check consistent binding
2741 if binding_i.binding_mode != binding_j.binding_mode {
2744 .or_insert((binding_j.span, binding_i.span));
2752 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2753 missing_vars.sort();
2754 for (_, v) in missing_vars {
2756 *v.origin.iter().next().unwrap(),
2757 ResolutionError::VariableNotBoundInPattern(v));
2759 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2760 inconsistent_vars.sort();
2761 for (name, v) in inconsistent_vars {
2762 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2766 fn resolve_arm(&mut self, arm: &Arm) {
2767 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2769 let mut bindings_list = FxHashMap();
2770 for pattern in &arm.pats {
2771 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2774 // This has to happen *after* we determine which pat_idents are variants
2775 self.check_consistent_bindings(&arm.pats);
2778 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2781 self.visit_expr(&arm.body);
2783 self.ribs[ValueNS].pop();
2786 fn resolve_block(&mut self, block: &Block) {
2787 debug!("(resolving block) entering block");
2788 // Move down in the graph, if there's an anonymous module rooted here.
2789 let orig_module = self.current_module;
2790 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2792 let mut num_macro_definition_ribs = 0;
2793 if let Some(anonymous_module) = anonymous_module {
2794 debug!("(resolving block) found anonymous module, moving down");
2795 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2796 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2797 self.current_module = anonymous_module;
2798 self.finalize_current_module_macro_resolutions();
2800 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2803 // Descend into the block.
2804 for stmt in &block.stmts {
2805 if let ast::StmtKind::Item(ref item) = stmt.node {
2806 if let ast::ItemKind::MacroDef(..) = item.node {
2807 num_macro_definition_ribs += 1;
2808 let def = self.definitions.local_def_id(item.id);
2809 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2810 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2814 self.visit_stmt(stmt);
2818 self.current_module = orig_module;
2819 for _ in 0 .. num_macro_definition_ribs {
2820 self.ribs[ValueNS].pop();
2821 self.label_ribs.pop();
2823 self.ribs[ValueNS].pop();
2824 if anonymous_module.is_some() {
2825 self.ribs[TypeNS].pop();
2827 debug!("(resolving block) leaving block");
2830 fn fresh_binding(&mut self,
2833 outer_pat_id: NodeId,
2834 pat_src: PatternSource,
2835 bindings: &mut FxHashMap<Ident, NodeId>)
2837 // Add the binding to the local ribs, if it
2838 // doesn't already exist in the bindings map. (We
2839 // must not add it if it's in the bindings map
2840 // because that breaks the assumptions later
2841 // passes make about or-patterns.)
2842 let ident = ident.modern_and_legacy();
2843 let mut def = Def::Local(pat_id);
2844 match bindings.get(&ident).cloned() {
2845 Some(id) if id == outer_pat_id => {
2846 // `Variant(a, a)`, error
2850 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2854 Some(..) if pat_src == PatternSource::FnParam => {
2855 // `fn f(a: u8, a: u8)`, error
2859 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2863 Some(..) if pat_src == PatternSource::Match ||
2864 pat_src == PatternSource::IfLet ||
2865 pat_src == PatternSource::WhileLet => {
2866 // `Variant1(a) | Variant2(a)`, ok
2867 // Reuse definition from the first `a`.
2868 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2871 span_bug!(ident.span, "two bindings with the same name from \
2872 unexpected pattern source {:?}", pat_src);
2875 // A completely fresh binding, add to the lists if it's valid.
2876 if ident.name != keywords::Invalid.name() {
2877 bindings.insert(ident, outer_pat_id);
2878 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2883 PathResolution::new(def)
2886 fn resolve_pattern(&mut self,
2888 pat_src: PatternSource,
2889 // Maps idents to the node ID for the
2890 // outermost pattern that binds them.
2891 bindings: &mut FxHashMap<Ident, NodeId>) {
2892 // Visit all direct subpatterns of this pattern.
2893 let outer_pat_id = pat.id;
2894 pat.walk(&mut |pat| {
2896 PatKind::Ident(bmode, ident, ref opt_pat) => {
2897 // First try to resolve the identifier as some existing
2898 // entity, then fall back to a fresh binding.
2899 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2901 .and_then(LexicalScopeBinding::item);
2902 let resolution = binding.map(NameBinding::def).and_then(|def| {
2903 let is_syntactic_ambiguity = opt_pat.is_none() &&
2904 bmode == BindingMode::ByValue(Mutability::Immutable);
2906 Def::StructCtor(_, CtorKind::Const) |
2907 Def::VariantCtor(_, CtorKind::Const) |
2908 Def::Const(..) if is_syntactic_ambiguity => {
2909 // Disambiguate in favor of a unit struct/variant
2910 // or constant pattern.
2911 self.record_use(ident, ValueNS, binding.unwrap());
2912 Some(PathResolution::new(def))
2914 Def::StructCtor(..) | Def::VariantCtor(..) |
2915 Def::Const(..) | Def::Static(..) => {
2916 // This is unambiguously a fresh binding, either syntactically
2917 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2918 // to something unusable as a pattern (e.g. constructor function),
2919 // but we still conservatively report an error, see
2920 // issues/33118#issuecomment-233962221 for one reason why.
2924 ResolutionError::BindingShadowsSomethingUnacceptable(
2925 pat_src.descr(), ident.name, binding.unwrap())
2929 Def::Fn(..) | Def::Err => {
2930 // These entities are explicitly allowed
2931 // to be shadowed by fresh bindings.
2935 span_bug!(ident.span, "unexpected definition for an \
2936 identifier in pattern: {:?}", def);
2939 }).unwrap_or_else(|| {
2940 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2943 self.record_def(pat.id, resolution);
2946 PatKind::TupleStruct(ref path, ..) => {
2947 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2950 PatKind::Path(ref qself, ref path) => {
2951 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2954 PatKind::Struct(ref path, ..) => {
2955 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2963 visit::walk_pat(self, pat);
2966 // High-level and context dependent path resolution routine.
2967 // Resolves the path and records the resolution into definition map.
2968 // If resolution fails tries several techniques to find likely
2969 // resolution candidates, suggest imports or other help, and report
2970 // errors in user friendly way.
2971 fn smart_resolve_path(&mut self,
2973 qself: Option<&QSelf>,
2977 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2980 /// A variant of `smart_resolve_path` where you also specify extra
2981 /// information about where the path came from; this extra info is
2982 /// sometimes needed for the lint that recommends rewriting
2983 /// absolute paths to `crate`, so that it knows how to frame the
2984 /// suggestion. If you are just resolving a path like `foo::bar`
2985 /// that appears...somewhere, though, then you just want
2986 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2987 /// already provides.
2988 fn smart_resolve_path_with_crate_lint(
2991 qself: Option<&QSelf>,
2994 crate_lint: CrateLint
2995 ) -> PathResolution {
2996 let segments = &path.segments.iter()
2997 .map(|seg| seg.ident)
2998 .collect::<Vec<_>>();
2999 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
3002 fn smart_resolve_path_fragment(&mut self,
3004 qself: Option<&QSelf>,
3008 crate_lint: CrateLint)
3010 let ident_span = path.last().map_or(span, |ident| ident.span);
3011 let ns = source.namespace();
3012 let is_expected = &|def| source.is_expected(def);
3013 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3015 // Base error is amended with one short label and possibly some longer helps/notes.
3016 let report_errors = |this: &mut Self, def: Option<Def>| {
3017 // Make the base error.
3018 let expected = source.descr_expected();
3019 let path_str = names_to_string(path);
3020 let code = source.error_code(def.is_some());
3021 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3022 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3023 format!("not a {}", expected),
3026 let item_str = path[path.len() - 1];
3027 let item_span = path[path.len() - 1].span;
3028 let (mod_prefix, mod_str) = if path.len() == 1 {
3029 (String::new(), "this scope".to_string())
3030 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
3031 (String::new(), "the crate root".to_string())
3033 let mod_path = &path[..path.len() - 1];
3034 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
3035 false, span, CrateLint::No) {
3036 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3039 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3040 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
3042 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3043 format!("not found in {}", mod_str),
3046 let code = DiagnosticId::Error(code.into());
3047 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3049 // Emit special messages for unresolved `Self` and `self`.
3050 if is_self_type(path, ns) {
3051 __diagnostic_used!(E0411);
3052 err.code(DiagnosticId::Error("E0411".into()));
3053 let available_in = if this.session.features_untracked().self_in_typedefs {
3054 "impls, traits, and type definitions"
3058 err.span_label(span, format!("`Self` is only available in {}", available_in));
3059 return (err, Vec::new());
3061 if is_self_value(path, ns) {
3062 __diagnostic_used!(E0424);
3063 err.code(DiagnosticId::Error("E0424".into()));
3064 err.span_label(span, format!("`self` value is only available in \
3065 methods with `self` parameter"));
3066 return (err, Vec::new());
3069 // Try to lookup the name in more relaxed fashion for better error reporting.
3070 let ident = *path.last().unwrap();
3071 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3072 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3073 let enum_candidates =
3074 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3075 let mut enum_candidates = enum_candidates.iter()
3076 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3077 enum_candidates.sort();
3078 for (sp, variant_path, enum_path) in enum_candidates {
3080 let msg = format!("there is an enum variant `{}`, \
3086 err.span_suggestion_with_applicability(
3088 "you can try using the variant's enum",
3090 Applicability::MachineApplicable,
3095 if path.len() == 1 && this.self_type_is_available(span) {
3096 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3097 let self_is_available = this.self_value_is_available(path[0].span, span);
3099 AssocSuggestion::Field => {
3100 err.span_suggestion_with_applicability(
3103 format!("self.{}", path_str),
3104 Applicability::MachineApplicable,
3106 if !self_is_available {
3107 err.span_label(span, format!("`self` value is only available in \
3108 methods with `self` parameter"));
3111 AssocSuggestion::MethodWithSelf if self_is_available => {
3112 err.span_suggestion_with_applicability(
3115 format!("self.{}", path_str),
3116 Applicability::MachineApplicable,
3119 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3120 err.span_suggestion_with_applicability(
3123 format!("Self::{}", path_str),
3124 Applicability::MachineApplicable,
3128 return (err, candidates);
3132 let mut levenshtein_worked = false;
3135 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3136 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3137 levenshtein_worked = true;
3140 // Try context dependent help if relaxed lookup didn't work.
3141 if let Some(def) = def {
3142 match (def, source) {
3143 (Def::Macro(..), _) => {
3144 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3145 return (err, candidates);
3147 (Def::TyAlias(..), PathSource::Trait(_)) => {
3148 err.span_label(span, "type aliases cannot be used for traits");
3149 return (err, candidates);
3151 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3152 ExprKind::Field(_, ident) => {
3153 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3155 return (err, candidates);
3157 ExprKind::MethodCall(ref segment, ..) => {
3158 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3159 path_str, segment.ident));
3160 return (err, candidates);
3164 (Def::Enum(..), PathSource::TupleStruct)
3165 | (Def::Enum(..), PathSource::Expr(..)) => {
3166 if let Some(variants) = this.collect_enum_variants(def) {
3167 err.note(&format!("did you mean to use one \
3168 of the following variants?\n{}",
3170 .map(|suggestion| path_names_to_string(suggestion))
3171 .map(|suggestion| format!("- `{}`", suggestion))
3172 .collect::<Vec<_>>()
3176 err.note("did you mean to use one of the enum's variants?");
3178 return (err, candidates);
3180 (Def::Struct(def_id), _) if ns == ValueNS => {
3181 if let Some((ctor_def, ctor_vis))
3182 = this.struct_constructors.get(&def_id).cloned() {
3183 let accessible_ctor = this.is_accessible(ctor_vis);
3184 if is_expected(ctor_def) && !accessible_ctor {
3185 err.span_label(span, format!("constructor is not visible \
3186 here due to private fields"));
3189 // HACK(estebank): find a better way to figure out that this was a
3190 // parser issue where a struct literal is being used on an expression
3191 // where a brace being opened means a block is being started. Look
3192 // ahead for the next text to see if `span` is followed by a `{`.
3193 let cm = this.session.source_map();
3196 sp = cm.next_point(sp);
3197 match cm.span_to_snippet(sp) {
3198 Ok(ref snippet) => {
3199 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3206 let followed_by_brace = match cm.span_to_snippet(sp) {
3207 Ok(ref snippet) if snippet == "{" => true,
3210 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3213 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3218 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3222 return (err, candidates);
3224 (Def::Union(..), _) |
3225 (Def::Variant(..), _) |
3226 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3227 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3229 return (err, candidates);
3231 (Def::SelfTy(..), _) if ns == ValueNS => {
3232 err.span_label(span, fallback_label);
3233 err.note("can't use `Self` as a constructor, you must use the \
3234 implemented struct");
3235 return (err, candidates);
3237 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3238 err.note("can't use a type alias as a constructor");
3239 return (err, candidates);
3246 if !levenshtein_worked {
3247 err.span_label(base_span, fallback_label);
3248 this.type_ascription_suggestion(&mut err, base_span);
3252 let report_errors = |this: &mut Self, def: Option<Def>| {
3253 let (err, candidates) = report_errors(this, def);
3254 let def_id = this.current_module.normal_ancestor_id;
3255 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3256 let better = def.is_some();
3257 this.use_injections.push(UseError { err, candidates, node_id, better });
3258 err_path_resolution()
3261 let resolution = match self.resolve_qpath_anywhere(
3267 source.defer_to_typeck(),
3268 source.global_by_default(),
3271 Some(resolution) if resolution.unresolved_segments() == 0 => {
3272 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3275 // Add a temporary hack to smooth the transition to new struct ctor
3276 // visibility rules. See #38932 for more details.
3278 if let Def::Struct(def_id) = resolution.base_def() {
3279 if let Some((ctor_def, ctor_vis))
3280 = self.struct_constructors.get(&def_id).cloned() {
3281 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3282 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3283 self.session.buffer_lint(lint, id, span,
3284 "private struct constructors are not usable through \
3285 re-exports in outer modules",
3287 res = Some(PathResolution::new(ctor_def));
3292 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3295 Some(resolution) if source.defer_to_typeck() => {
3296 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3297 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3298 // it needs to be added to the trait map.
3300 let item_name = *path.last().unwrap();
3301 let traits = self.get_traits_containing_item(item_name, ns);
3302 self.trait_map.insert(id, traits);
3306 _ => report_errors(self, None)
3309 if let PathSource::TraitItem(..) = source {} else {
3310 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3311 self.record_def(id, resolution);
3316 fn type_ascription_suggestion(&self,
3317 err: &mut DiagnosticBuilder,
3319 debug!("type_ascription_suggetion {:?}", base_span);
3320 let cm = self.session.source_map();
3321 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3322 if let Some(sp) = self.current_type_ascription.last() {
3324 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3325 sp = cm.next_point(sp);
3326 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3327 debug!("snippet {:?}", snippet);
3328 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3329 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3330 debug!("{:?} {:?}", line_sp, line_base_sp);
3332 err.span_label(base_span,
3333 "expecting a type here because of type ascription");
3334 if line_sp != line_base_sp {
3335 err.span_suggestion_short(sp,
3336 "did you mean to use `;` here instead?",
3340 } else if snippet.trim().len() != 0 {
3341 debug!("tried to find type ascription `:` token, couldn't find it");
3351 fn self_type_is_available(&mut self, span: Span) -> bool {
3352 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3353 TypeNS, None, span);
3354 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3357 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3358 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3359 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3360 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3363 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3364 fn resolve_qpath_anywhere(&mut self,
3366 qself: Option<&QSelf>,
3368 primary_ns: Namespace,
3370 defer_to_typeck: bool,
3371 global_by_default: bool,
3372 crate_lint: CrateLint)
3373 -> Option<PathResolution> {
3374 let mut fin_res = None;
3375 // FIXME: can't resolve paths in macro namespace yet, macros are
3376 // processed by the little special hack below.
3377 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3378 if i == 0 || ns != primary_ns {
3379 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3380 // If defer_to_typeck, then resolution > no resolution,
3381 // otherwise full resolution > partial resolution > no resolution.
3382 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3384 res => if fin_res.is_none() { fin_res = res },
3388 if primary_ns != MacroNS &&
3389 (self.macro_names.contains(&path[0].modern()) ||
3390 self.builtin_macros.get(&path[0].name).cloned()
3391 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3392 self.macro_use_prelude.get(&path[0].name).cloned()
3393 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3394 // Return some dummy definition, it's enough for error reporting.
3396 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3402 /// Handles paths that may refer to associated items.
3403 fn resolve_qpath(&mut self,
3405 qself: Option<&QSelf>,
3409 global_by_default: bool,
3410 crate_lint: CrateLint)
3411 -> Option<PathResolution> {
3413 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3414 ns={:?}, span={:?}, global_by_default={:?})",
3423 if let Some(qself) = qself {
3424 if qself.position == 0 {
3425 // This is a case like `<T>::B`, where there is no
3426 // trait to resolve. In that case, we leave the `B`
3427 // segment to be resolved by type-check.
3428 return Some(PathResolution::with_unresolved_segments(
3429 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3433 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3435 // Currently, `path` names the full item (`A::B::C`, in
3436 // our example). so we extract the prefix of that that is
3437 // the trait (the slice upto and including
3438 // `qself.position`). And then we recursively resolve that,
3439 // but with `qself` set to `None`.
3441 // However, setting `qself` to none (but not changing the
3442 // span) loses the information about where this path
3443 // *actually* appears, so for the purposes of the crate
3444 // lint we pass along information that this is the trait
3445 // name from a fully qualified path, and this also
3446 // contains the full span (the `CrateLint::QPathTrait`).
3447 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3448 let res = self.smart_resolve_path_fragment(
3451 &path[..qself.position + 1],
3453 PathSource::TraitItem(ns),
3454 CrateLint::QPathTrait {
3456 qpath_span: qself.path_span,
3460 // The remaining segments (the `C` in our example) will
3461 // have to be resolved by type-check, since that requires doing
3462 // trait resolution.
3463 return Some(PathResolution::with_unresolved_segments(
3464 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3468 let result = match self.resolve_path(
3476 PathResult::NonModule(path_res) => path_res,
3477 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3478 PathResolution::new(module.def().unwrap())
3480 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3481 // don't report an error right away, but try to fallback to a primitive type.
3482 // So, we are still able to successfully resolve something like
3484 // use std::u8; // bring module u8 in scope
3485 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3486 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3487 // // not to non-existent std::u8::max_value
3490 // Such behavior is required for backward compatibility.
3491 // The same fallback is used when `a` resolves to nothing.
3492 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3493 PathResult::Failed(..)
3494 if (ns == TypeNS || path.len() > 1) &&
3495 self.primitive_type_table.primitive_types
3496 .contains_key(&path[0].name) => {
3497 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3498 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3500 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3501 PathResolution::new(module.def().unwrap()),
3502 PathResult::Failed(span, msg, false) => {
3503 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3504 err_path_resolution()
3506 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3507 PathResult::Failed(..) => return None,
3508 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3511 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3512 path[0].name != keywords::CrateRoot.name() &&
3513 path[0].name != keywords::DollarCrate.name() {
3514 let unqualified_result = {
3515 match self.resolve_path(
3517 &[*path.last().unwrap()],
3523 PathResult::NonModule(path_res) => path_res.base_def(),
3524 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3525 module.def().unwrap(),
3526 _ => return Some(result),
3529 if result.base_def() == unqualified_result {
3530 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3531 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3540 base_module: Option<ModuleOrUniformRoot<'a>>,
3542 opt_ns: Option<Namespace>, // `None` indicates a module path
3545 crate_lint: CrateLint,
3546 ) -> PathResult<'a> {
3547 self.resolve_path_with_parent_expansion(base_module, path, opt_ns, Mark::root(),
3548 record_used, path_span, crate_lint)
3551 fn resolve_path_with_parent_expansion(
3553 base_module: Option<ModuleOrUniformRoot<'a>>,
3555 opt_ns: Option<Namespace>, // `None` indicates a module path
3556 parent_expansion: Mark,
3559 crate_lint: CrateLint,
3560 ) -> PathResult<'a> {
3561 let mut module = base_module;
3562 let mut allow_super = true;
3563 let mut second_binding = None;
3566 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3567 path_span={:?}, crate_lint={:?})",
3575 for (i, &ident) in path.iter().enumerate() {
3576 debug!("resolve_path ident {} {:?}", i, ident);
3577 let is_last = i == path.len() - 1;
3578 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3579 let name = ident.name;
3581 allow_super &= ns == TypeNS &&
3582 (name == keywords::SelfValue.name() ||
3583 name == keywords::Super.name());
3586 if allow_super && name == keywords::Super.name() {
3587 let mut ctxt = ident.span.ctxt().modern();
3588 let self_module = match i {
3589 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3591 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3595 if let Some(self_module) = self_module {
3596 if let Some(parent) = self_module.parent {
3597 module = Some(ModuleOrUniformRoot::Module(
3598 self.resolve_self(&mut ctxt, parent)));
3602 let msg = "There are too many initial `super`s.".to_string();
3603 return PathResult::Failed(ident.span, msg, false);
3606 if name == keywords::SelfValue.name() {
3607 let mut ctxt = ident.span.ctxt().modern();
3608 module = Some(ModuleOrUniformRoot::Module(
3609 self.resolve_self(&mut ctxt, self.current_module)));
3612 if name == keywords::Extern.name() ||
3613 name == keywords::CrateRoot.name() &&
3614 self.session.features_untracked().extern_absolute_paths &&
3615 self.session.rust_2018() {
3616 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3619 if name == keywords::CrateRoot.name() ||
3620 name == keywords::Crate.name() ||
3621 name == keywords::DollarCrate.name() {
3622 // `::a::b`, `crate::a::b` or `$crate::a::b`
3623 module = Some(ModuleOrUniformRoot::Module(
3624 self.resolve_crate_root(ident)));
3630 // Report special messages for path segment keywords in wrong positions.
3631 if ident.is_path_segment_keyword() && i != 0 {
3632 let name_str = if name == keywords::CrateRoot.name() {
3633 "crate root".to_string()
3635 format!("`{}`", name)
3637 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3638 format!("global paths cannot start with {}", name_str)
3640 format!("{} in paths can only be used in start position", name_str)
3642 return PathResult::Failed(ident.span, msg, false);
3645 let binding = if let Some(module) = module {
3646 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3647 } else if opt_ns == Some(MacroNS) {
3648 assert!(ns == TypeNS);
3649 self.resolve_lexical_macro_path_segment(ident, ns, None, parent_expansion,
3650 record_used, record_used, path_span)
3651 .map(|(binding, _)| binding)
3653 let record_used_id =
3654 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3655 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3656 // we found a locally-imported or available item/module
3657 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3658 // we found a local variable or type param
3659 Some(LexicalScopeBinding::Def(def))
3660 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3661 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3665 _ => Err(if record_used { Determined } else { Undetermined }),
3672 second_binding = Some(binding);
3674 let def = binding.def();
3675 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3676 if let Some(next_module) = binding.module() {
3677 module = Some(ModuleOrUniformRoot::Module(next_module));
3678 } else if def == Def::ToolMod && i + 1 != path.len() {
3679 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3680 return PathResult::NonModule(PathResolution::new(def));
3681 } else if def == Def::Err {
3682 return PathResult::NonModule(err_path_resolution());
3683 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3684 self.lint_if_path_starts_with_module(
3690 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3691 def, path.len() - i - 1
3694 return PathResult::Failed(ident.span,
3695 format!("Not a module `{}`", ident),
3699 Err(Undetermined) => return PathResult::Indeterminate,
3700 Err(Determined) => {
3701 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3702 if opt_ns.is_some() && !module.is_normal() {
3703 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3704 module.def().unwrap(), path.len() - i
3708 let module_def = match module {
3709 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3712 let msg = if module_def == self.graph_root.def() {
3713 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3714 let mut candidates =
3715 self.lookup_import_candidates(name, TypeNS, is_mod);
3716 candidates.sort_by_cached_key(|c| {
3717 (c.path.segments.len(), c.path.to_string())
3719 if let Some(candidate) = candidates.get(0) {
3720 format!("Did you mean `{}`?", candidate.path)
3722 format!("Maybe a missing `extern crate {};`?", ident)
3725 format!("Use of undeclared type or module `{}`", ident)
3727 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3729 return PathResult::Failed(ident.span, msg, is_last);
3734 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3736 PathResult::Module(module.unwrap_or_else(|| {
3737 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3742 fn lint_if_path_starts_with_module(
3744 crate_lint: CrateLint,
3747 second_binding: Option<&NameBinding>,
3749 // In the 2018 edition this lint is a hard error, so nothing to do
3750 if self.session.rust_2018() {
3754 // In the 2015 edition there's no use in emitting lints unless the
3755 // crate's already enabled the feature that we're going to suggest
3756 if !self.session.features_untracked().crate_in_paths {
3760 let (diag_id, diag_span) = match crate_lint {
3761 CrateLint::No => return,
3762 CrateLint::SimplePath(id) => (id, path_span),
3763 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3764 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3767 let first_name = match path.get(0) {
3768 Some(ident) => ident.name,
3772 // We're only interested in `use` paths which should start with
3773 // `{{root}}` or `extern` currently.
3774 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3779 // If this import looks like `crate::...` it's already good
3780 Some(ident) if ident.name == keywords::Crate.name() => return,
3781 // Otherwise go below to see if it's an extern crate
3783 // If the path has length one (and it's `CrateRoot` most likely)
3784 // then we don't know whether we're gonna be importing a crate or an
3785 // item in our crate. Defer this lint to elsewhere
3789 // If the first element of our path was actually resolved to an
3790 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3791 // warning, this looks all good!
3792 if let Some(binding) = second_binding {
3793 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3794 // Careful: we still want to rewrite paths from
3795 // renamed extern crates.
3796 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3802 let diag = lint::builtin::BuiltinLintDiagnostics
3803 ::AbsPathWithModule(diag_span);
3804 self.session.buffer_lint_with_diagnostic(
3805 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3807 "absolute paths must start with `self`, `super`, \
3808 `crate`, or an external crate name in the 2018 edition",
3812 // Resolve a local definition, potentially adjusting for closures.
3813 fn adjust_local_def(&mut self,
3818 span: Span) -> Def {
3819 let ribs = &self.ribs[ns][rib_index + 1..];
3821 // An invalid forward use of a type parameter from a previous default.
3822 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3824 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3826 assert_eq!(def, Def::Err);
3832 span_bug!(span, "unexpected {:?} in bindings", def)
3834 Def::Local(node_id) => {
3837 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3838 ForwardTyParamBanRibKind => {
3839 // Nothing to do. Continue.
3841 ClosureRibKind(function_id) => {
3844 let seen = self.freevars_seen
3847 if let Some(&index) = seen.get(&node_id) {
3848 def = Def::Upvar(node_id, index, function_id);
3851 let vec = self.freevars
3854 let depth = vec.len();
3855 def = Def::Upvar(node_id, depth, function_id);
3862 seen.insert(node_id, depth);
3865 ItemRibKind | TraitOrImplItemRibKind => {
3866 // This was an attempt to access an upvar inside a
3867 // named function item. This is not allowed, so we
3870 resolve_error(self, span,
3871 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3875 ConstantItemRibKind => {
3876 // Still doesn't deal with upvars
3878 resolve_error(self, span,
3879 ResolutionError::AttemptToUseNonConstantValueInConstant);
3886 Def::TyParam(..) | Def::SelfTy(..) => {
3889 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3890 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3891 ConstantItemRibKind => {
3892 // Nothing to do. Continue.
3895 // This was an attempt to use a type parameter outside
3898 resolve_error(self, span,
3899 ResolutionError::TypeParametersFromOuterFunction(def));
3911 fn lookup_assoc_candidate<FilterFn>(&mut self,
3914 filter_fn: FilterFn)
3915 -> Option<AssocSuggestion>
3916 where FilterFn: Fn(Def) -> bool
3918 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3920 TyKind::Path(None, _) => Some(t.id),
3921 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3922 // This doesn't handle the remaining `Ty` variants as they are not
3923 // that commonly the self_type, it might be interesting to provide
3924 // support for those in future.
3929 // Fields are generally expected in the same contexts as locals.
3930 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3931 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3932 // Look for a field with the same name in the current self_type.
3933 if let Some(resolution) = self.def_map.get(&node_id) {
3934 match resolution.base_def() {
3935 Def::Struct(did) | Def::Union(did)
3936 if resolution.unresolved_segments() == 0 => {
3937 if let Some(field_names) = self.field_names.get(&did) {
3938 if field_names.iter().any(|&field_name| ident.name == field_name) {
3939 return Some(AssocSuggestion::Field);
3949 // Look for associated items in the current trait.
3950 if let Some((module, _)) = self.current_trait_ref {
3951 if let Ok(binding) = self.resolve_ident_in_module(
3952 ModuleOrUniformRoot::Module(module),
3958 let def = binding.def();
3960 return Some(if self.has_self.contains(&def.def_id()) {
3961 AssocSuggestion::MethodWithSelf
3963 AssocSuggestion::AssocItem
3972 fn lookup_typo_candidate<FilterFn>(&mut self,
3975 filter_fn: FilterFn,
3978 where FilterFn: Fn(Def) -> bool
3980 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3981 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3982 if let Some(binding) = resolution.borrow().binding {
3983 if filter_fn(binding.def()) {
3984 names.push(ident.name);
3990 let mut names = Vec::new();
3991 if path.len() == 1 {
3992 // Search in lexical scope.
3993 // Walk backwards up the ribs in scope and collect candidates.
3994 for rib in self.ribs[ns].iter().rev() {
3995 // Locals and type parameters
3996 for (ident, def) in &rib.bindings {
3997 if filter_fn(*def) {
3998 names.push(ident.name);
4002 if let ModuleRibKind(module) = rib.kind {
4003 // Items from this module
4004 add_module_candidates(module, &mut names);
4006 if let ModuleKind::Block(..) = module.kind {
4007 // We can see through blocks
4009 // Items from the prelude
4010 if !module.no_implicit_prelude {
4011 names.extend(self.extern_prelude.iter().cloned());
4012 if let Some(prelude) = self.prelude {
4013 add_module_candidates(prelude, &mut names);
4020 // Add primitive types to the mix
4021 if filter_fn(Def::PrimTy(Bool)) {
4023 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4027 // Search in module.
4028 let mod_path = &path[..path.len() - 1];
4029 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
4030 false, span, CrateLint::No) {
4031 if let ModuleOrUniformRoot::Module(module) = module {
4032 add_module_candidates(module, &mut names);
4037 let name = path[path.len() - 1].name;
4038 // Make sure error reporting is deterministic.
4039 names.sort_by_cached_key(|name| name.as_str());
4040 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4041 Some(found) if found != name => Some(found),
4046 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4047 where F: FnOnce(&mut Resolver)
4049 if let Some(label) = label {
4050 self.unused_labels.insert(id, label.ident.span);
4051 let def = Def::Label(id);
4052 self.with_label_rib(|this| {
4053 let ident = label.ident.modern_and_legacy();
4054 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4062 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4063 self.with_resolved_label(label, id, |this| this.visit_block(block));
4066 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4067 // First, record candidate traits for this expression if it could
4068 // result in the invocation of a method call.
4070 self.record_candidate_traits_for_expr_if_necessary(expr);
4072 // Next, resolve the node.
4074 ExprKind::Path(ref qself, ref path) => {
4075 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4076 visit::walk_expr(self, expr);
4079 ExprKind::Struct(ref path, ..) => {
4080 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4081 visit::walk_expr(self, expr);
4084 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4085 let def = self.search_label(label.ident, |rib, ident| {
4086 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4090 // Search again for close matches...
4091 // Picks the first label that is "close enough", which is not necessarily
4092 // the closest match
4093 let close_match = self.search_label(label.ident, |rib, ident| {
4094 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4095 find_best_match_for_name(names, &*ident.as_str(), None)
4097 self.record_def(expr.id, err_path_resolution());
4100 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4103 Some(Def::Label(id)) => {
4104 // Since this def is a label, it is never read.
4105 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4106 self.unused_labels.remove(&id);
4109 span_bug!(expr.span, "label wasn't mapped to a label def!");
4113 // visit `break` argument if any
4114 visit::walk_expr(self, expr);
4117 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4118 self.visit_expr(subexpression);
4120 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4121 let mut bindings_list = FxHashMap();
4123 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4125 // This has to happen *after* we determine which pat_idents are variants
4126 self.check_consistent_bindings(pats);
4127 self.visit_block(if_block);
4128 self.ribs[ValueNS].pop();
4130 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4133 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4135 ExprKind::While(ref subexpression, ref block, label) => {
4136 self.with_resolved_label(label, expr.id, |this| {
4137 this.visit_expr(subexpression);
4138 this.visit_block(block);
4142 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4143 self.with_resolved_label(label, expr.id, |this| {
4144 this.visit_expr(subexpression);
4145 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4146 let mut bindings_list = FxHashMap();
4148 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4150 // This has to happen *after* we determine which pat_idents are variants
4151 this.check_consistent_bindings(pats);
4152 this.visit_block(block);
4153 this.ribs[ValueNS].pop();
4157 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4158 self.visit_expr(subexpression);
4159 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4160 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4162 self.resolve_labeled_block(label, expr.id, block);
4164 self.ribs[ValueNS].pop();
4167 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4169 // Equivalent to `visit::walk_expr` + passing some context to children.
4170 ExprKind::Field(ref subexpression, _) => {
4171 self.resolve_expr(subexpression, Some(expr));
4173 ExprKind::MethodCall(ref segment, ref arguments) => {
4174 let mut arguments = arguments.iter();
4175 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4176 for argument in arguments {
4177 self.resolve_expr(argument, None);
4179 self.visit_path_segment(expr.span, segment);
4182 ExprKind::Call(ref callee, ref arguments) => {
4183 self.resolve_expr(callee, Some(expr));
4184 for argument in arguments {
4185 self.resolve_expr(argument, None);
4188 ExprKind::Type(ref type_expr, _) => {
4189 self.current_type_ascription.push(type_expr.span);
4190 visit::walk_expr(self, expr);
4191 self.current_type_ascription.pop();
4193 // Resolve the body of async exprs inside the async closure to which they desugar
4194 ExprKind::Async(_, async_closure_id, ref block) => {
4195 let rib_kind = ClosureRibKind(async_closure_id);
4196 self.ribs[ValueNS].push(Rib::new(rib_kind));
4197 self.label_ribs.push(Rib::new(rib_kind));
4198 self.visit_block(&block);
4199 self.label_ribs.pop();
4200 self.ribs[ValueNS].pop();
4202 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4203 // resolve the arguments within the proper scopes so that usages of them inside the
4204 // closure are detected as upvars rather than normal closure arg usages.
4206 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4207 ref fn_decl, ref body, _span,
4209 let rib_kind = ClosureRibKind(expr.id);
4210 self.ribs[ValueNS].push(Rib::new(rib_kind));
4211 self.label_ribs.push(Rib::new(rib_kind));
4212 // Resolve arguments:
4213 let mut bindings_list = FxHashMap();
4214 for argument in &fn_decl.inputs {
4215 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4216 self.visit_ty(&argument.ty);
4218 // No need to resolve return type-- the outer closure return type is
4219 // FunctionRetTy::Default
4221 // Now resolve the inner closure
4223 let rib_kind = ClosureRibKind(inner_closure_id);
4224 self.ribs[ValueNS].push(Rib::new(rib_kind));
4225 self.label_ribs.push(Rib::new(rib_kind));
4226 // No need to resolve arguments: the inner closure has none.
4227 // Resolve the return type:
4228 visit::walk_fn_ret_ty(self, &fn_decl.output);
4230 self.visit_expr(body);
4231 self.label_ribs.pop();
4232 self.ribs[ValueNS].pop();
4234 self.label_ribs.pop();
4235 self.ribs[ValueNS].pop();
4238 visit::walk_expr(self, expr);
4243 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4245 ExprKind::Field(_, ident) => {
4246 // FIXME(#6890): Even though you can't treat a method like a
4247 // field, we need to add any trait methods we find that match
4248 // the field name so that we can do some nice error reporting
4249 // later on in typeck.
4250 let traits = self.get_traits_containing_item(ident, ValueNS);
4251 self.trait_map.insert(expr.id, traits);
4253 ExprKind::MethodCall(ref segment, ..) => {
4254 debug!("(recording candidate traits for expr) recording traits for {}",
4256 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4257 self.trait_map.insert(expr.id, traits);
4265 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4266 -> Vec<TraitCandidate> {
4267 debug!("(getting traits containing item) looking for '{}'", ident.name);
4269 let mut found_traits = Vec::new();
4270 // Look for the current trait.
4271 if let Some((module, _)) = self.current_trait_ref {
4272 if self.resolve_ident_in_module(
4273 ModuleOrUniformRoot::Module(module),
4279 let def_id = module.def_id().unwrap();
4280 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4284 ident.span = ident.span.modern();
4285 let mut search_module = self.current_module;
4287 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4288 search_module = unwrap_or!(
4289 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4293 if let Some(prelude) = self.prelude {
4294 if !search_module.no_implicit_prelude {
4295 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4302 fn get_traits_in_module_containing_item(&mut self,
4306 found_traits: &mut Vec<TraitCandidate>) {
4307 assert!(ns == TypeNS || ns == ValueNS);
4308 let mut traits = module.traits.borrow_mut();
4309 if traits.is_none() {
4310 let mut collected_traits = Vec::new();
4311 module.for_each_child(|name, ns, binding| {
4312 if ns != TypeNS { return }
4313 if let Def::Trait(_) = binding.def() {
4314 collected_traits.push((name, binding));
4317 *traits = Some(collected_traits.into_boxed_slice());
4320 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4321 let module = binding.module().unwrap();
4322 let mut ident = ident;
4323 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4326 if self.resolve_ident_in_module_unadjusted(
4327 ModuleOrUniformRoot::Module(module),
4334 let import_id = match binding.kind {
4335 NameBindingKind::Import { directive, .. } => {
4336 self.maybe_unused_trait_imports.insert(directive.id);
4337 self.add_to_glob_map(directive.id, trait_name);
4342 let trait_def_id = module.def_id().unwrap();
4343 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4348 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4350 namespace: Namespace,
4351 start_module: &'a ModuleData<'a>,
4353 filter_fn: FilterFn)
4354 -> Vec<ImportSuggestion>
4355 where FilterFn: Fn(Def) -> bool
4357 let mut candidates = Vec::new();
4358 let mut worklist = Vec::new();
4359 let mut seen_modules = FxHashSet();
4360 let not_local_module = crate_name != keywords::Crate.ident();
4361 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4363 while let Some((in_module,
4365 in_module_is_extern)) = worklist.pop() {
4366 self.populate_module_if_necessary(in_module);
4368 // We have to visit module children in deterministic order to avoid
4369 // instabilities in reported imports (#43552).
4370 in_module.for_each_child_stable(|ident, ns, name_binding| {
4371 // avoid imports entirely
4372 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4373 // avoid non-importable candidates as well
4374 if !name_binding.is_importable() { return; }
4376 // collect results based on the filter function
4377 if ident.name == lookup_name && ns == namespace {
4378 if filter_fn(name_binding.def()) {
4380 let mut segms = path_segments.clone();
4381 if self.session.rust_2018() {
4382 // crate-local absolute paths start with `crate::` in edition 2018
4383 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4385 0, ast::PathSegment::from_ident(crate_name)
4389 segms.push(ast::PathSegment::from_ident(ident));
4391 span: name_binding.span,
4394 // the entity is accessible in the following cases:
4395 // 1. if it's defined in the same crate, it's always
4396 // accessible (since private entities can be made public)
4397 // 2. if it's defined in another crate, it's accessible
4398 // only if both the module is public and the entity is
4399 // declared as public (due to pruning, we don't explore
4400 // outside crate private modules => no need to check this)
4401 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4402 candidates.push(ImportSuggestion { path: path });
4407 // collect submodules to explore
4408 if let Some(module) = name_binding.module() {
4410 let mut path_segments = path_segments.clone();
4411 path_segments.push(ast::PathSegment::from_ident(ident));
4413 let is_extern_crate_that_also_appears_in_prelude =
4414 name_binding.is_extern_crate() &&
4415 self.session.rust_2018();
4417 let is_visible_to_user =
4418 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4420 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4421 // add the module to the lookup
4422 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4423 if seen_modules.insert(module.def_id().unwrap()) {
4424 worklist.push((module, path_segments, is_extern));
4434 /// When name resolution fails, this method can be used to look up candidate
4435 /// entities with the expected name. It allows filtering them using the
4436 /// supplied predicate (which should be used to only accept the types of
4437 /// definitions expected e.g. traits). The lookup spans across all crates.
4439 /// NOTE: The method does not look into imports, but this is not a problem,
4440 /// since we report the definitions (thus, the de-aliased imports).
4441 fn lookup_import_candidates<FilterFn>(&mut self,
4443 namespace: Namespace,
4444 filter_fn: FilterFn)
4445 -> Vec<ImportSuggestion>
4446 where FilterFn: Fn(Def) -> bool
4448 let mut suggestions = vec![];
4451 self.lookup_import_candidates_from_module(
4452 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4456 if self.session.features_untracked().extern_prelude {
4457 let extern_prelude_names = self.extern_prelude.clone();
4458 for &krate_name in extern_prelude_names.iter() {
4459 let krate_ident = Ident::with_empty_ctxt(krate_name);
4460 let external_prelude_module = self.load_extern_prelude_crate_if_needed(krate_ident);
4463 self.lookup_import_candidates_from_module(
4464 lookup_name, namespace, external_prelude_module, krate_ident, &filter_fn
4473 fn find_module(&mut self,
4475 -> Option<(Module<'a>, ImportSuggestion)>
4477 let mut result = None;
4478 let mut worklist = Vec::new();
4479 let mut seen_modules = FxHashSet();
4480 worklist.push((self.graph_root, Vec::new()));
4482 while let Some((in_module, path_segments)) = worklist.pop() {
4483 // abort if the module is already found
4484 if result.is_some() { break; }
4486 self.populate_module_if_necessary(in_module);
4488 in_module.for_each_child_stable(|ident, _, name_binding| {
4489 // abort if the module is already found or if name_binding is private external
4490 if result.is_some() || !name_binding.vis.is_visible_locally() {
4493 if let Some(module) = name_binding.module() {
4495 let mut path_segments = path_segments.clone();
4496 path_segments.push(ast::PathSegment::from_ident(ident));
4497 if module.def() == Some(module_def) {
4499 span: name_binding.span,
4500 segments: path_segments,
4502 result = Some((module, ImportSuggestion { path: path }));
4504 // add the module to the lookup
4505 if seen_modules.insert(module.def_id().unwrap()) {
4506 worklist.push((module, path_segments));
4516 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4517 if let Def::Enum(..) = enum_def {} else {
4518 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4521 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4522 self.populate_module_if_necessary(enum_module);
4524 let mut variants = Vec::new();
4525 enum_module.for_each_child_stable(|ident, _, name_binding| {
4526 if let Def::Variant(..) = name_binding.def() {
4527 let mut segms = enum_import_suggestion.path.segments.clone();
4528 segms.push(ast::PathSegment::from_ident(ident));
4529 variants.push(Path {
4530 span: name_binding.span,
4539 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4540 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4541 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4542 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4546 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4548 ast::VisibilityKind::Public => ty::Visibility::Public,
4549 ast::VisibilityKind::Crate(..) => {
4550 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4552 ast::VisibilityKind::Inherited => {
4553 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4555 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4556 // Visibilities are resolved as global by default, add starting root segment.
4557 let segments = path.make_root().iter().chain(path.segments.iter())
4558 .map(|seg| seg.ident)
4559 .collect::<Vec<_>>();
4560 let def = self.smart_resolve_path_fragment(
4565 PathSource::Visibility,
4566 CrateLint::SimplePath(id),
4568 if def == Def::Err {
4569 ty::Visibility::Public
4571 let vis = ty::Visibility::Restricted(def.def_id());
4572 if self.is_accessible(vis) {
4575 self.session.span_err(path.span, "visibilities can only be restricted \
4576 to ancestor modules");
4577 ty::Visibility::Public
4584 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4585 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4588 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4589 vis.is_accessible_from(module.normal_ancestor_id, self)
4592 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4593 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4595 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4597 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4598 let note = if b1.expansion != Mark::root() {
4599 Some(if let Def::Macro(..) = b1.def() {
4600 format!("macro-expanded {} do not shadow",
4601 if b1.is_import() { "macro imports" } else { "macros" })
4603 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4604 if b1.is_import() { "imports" } else { "items" })
4606 } else if b1.is_glob_import() {
4607 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4612 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4613 err.span_label(ident.span, "ambiguous name");
4614 err.span_note(b1.span, &msg1);
4616 Def::Macro(..) if b2.span.is_dummy() =>
4617 err.note(&format!("`{}` is also a builtin macro", ident)),
4618 _ => err.span_note(b2.span, &msg2),
4620 if let Some(note) = note {
4626 fn report_errors(&mut self, krate: &Crate) {
4627 self.report_with_use_injections(krate);
4628 self.report_proc_macro_import(krate);
4629 let mut reported_spans = FxHashSet();
4631 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4632 let msg = "macro-expanded `macro_export` macros from the current crate \
4633 cannot be referred to by absolute paths";
4634 self.session.buffer_lint_with_diagnostic(
4635 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4636 CRATE_NODE_ID, span_use, msg,
4637 lint::builtin::BuiltinLintDiagnostics::
4638 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4642 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4643 if reported_spans.insert(ident.span) {
4644 self.report_ambiguity_error(ident, b1, b2);
4648 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4649 if !reported_spans.insert(span) { continue }
4650 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4654 fn report_with_use_injections(&mut self, krate: &Crate) {
4655 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4656 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4657 if !candidates.is_empty() {
4658 show_candidates(&mut err, span, &candidates, better, found_use);
4664 fn report_conflict<'b>(&mut self,
4668 new_binding: &NameBinding<'b>,
4669 old_binding: &NameBinding<'b>) {
4670 // Error on the second of two conflicting names
4671 if old_binding.span.lo() > new_binding.span.lo() {
4672 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4675 let container = match parent.kind {
4676 ModuleKind::Def(Def::Mod(_), _) => "module",
4677 ModuleKind::Def(Def::Trait(_), _) => "trait",
4678 ModuleKind::Block(..) => "block",
4682 let old_noun = match old_binding.is_import() {
4684 false => "definition",
4687 let new_participle = match new_binding.is_import() {
4692 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4694 if let Some(s) = self.name_already_seen.get(&name) {
4700 let old_kind = match (ns, old_binding.module()) {
4701 (ValueNS, _) => "value",
4702 (MacroNS, _) => "macro",
4703 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4704 (TypeNS, Some(module)) if module.is_normal() => "module",
4705 (TypeNS, Some(module)) if module.is_trait() => "trait",
4706 (TypeNS, _) => "type",
4709 let msg = format!("the name `{}` is defined multiple times", name);
4711 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4712 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4713 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4714 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4715 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4717 _ => match (old_binding.is_import(), new_binding.is_import()) {
4718 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4719 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4720 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4724 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4729 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4730 if !old_binding.span.is_dummy() {
4731 err.span_label(self.session.source_map().def_span(old_binding.span),
4732 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4735 // See https://github.com/rust-lang/rust/issues/32354
4736 if old_binding.is_import() || new_binding.is_import() {
4737 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4743 let cm = self.session.source_map();
4744 let rename_msg = "You can use `as` to change the binding name of the import";
4746 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4747 binding.is_renamed_extern_crate()) {
4748 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4749 format!("Other{}", name)
4751 format!("other_{}", name)
4754 err.span_suggestion_with_applicability(
4757 if snippet.ends_with(';') {
4758 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4760 format!("{} as {}", snippet, suggested_name)
4762 Applicability::MachineApplicable,
4765 err.span_label(binding.span, rename_msg);
4770 self.name_already_seen.insert(name, span);
4774 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4775 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4778 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4779 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4782 fn names_to_string(idents: &[Ident]) -> String {
4783 let mut result = String::new();
4784 for (i, ident) in idents.iter()
4785 .filter(|ident| ident.name != keywords::CrateRoot.name())
4788 result.push_str("::");
4790 result.push_str(&ident.as_str());
4795 fn path_names_to_string(path: &Path) -> String {
4796 names_to_string(&path.segments.iter()
4797 .map(|seg| seg.ident)
4798 .collect::<Vec<_>>())
4801 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4802 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4803 let variant_path = &suggestion.path;
4804 let variant_path_string = path_names_to_string(variant_path);
4806 let path_len = suggestion.path.segments.len();
4807 let enum_path = ast::Path {
4808 span: suggestion.path.span,
4809 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4811 let enum_path_string = path_names_to_string(&enum_path);
4813 (suggestion.path.span, variant_path_string, enum_path_string)
4817 /// When an entity with a given name is not available in scope, we search for
4818 /// entities with that name in all crates. This method allows outputting the
4819 /// results of this search in a programmer-friendly way
4820 fn show_candidates(err: &mut DiagnosticBuilder,
4821 // This is `None` if all placement locations are inside expansions
4823 candidates: &[ImportSuggestion],
4827 // we want consistent results across executions, but candidates are produced
4828 // by iterating through a hash map, so make sure they are ordered:
4829 let mut path_strings: Vec<_> =
4830 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4831 path_strings.sort();
4833 let better = if better { "better " } else { "" };
4834 let msg_diff = match path_strings.len() {
4835 1 => " is found in another module, you can import it",
4836 _ => "s are found in other modules, you can import them",
4838 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4840 if let Some(span) = span {
4841 for candidate in &mut path_strings {
4842 // produce an additional newline to separate the new use statement
4843 // from the directly following item.
4844 let additional_newline = if found_use {
4849 *candidate = format!("use {};\n{}", candidate, additional_newline);
4852 err.span_suggestions(span, &msg, path_strings);
4856 for candidate in path_strings {
4858 msg.push_str(&candidate);
4863 /// A somewhat inefficient routine to obtain the name of a module.
4864 fn module_to_string(module: Module) -> Option<String> {
4865 let mut names = Vec::new();
4867 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4868 if let ModuleKind::Def(_, name) = module.kind {
4869 if let Some(parent) = module.parent {
4870 names.push(Ident::with_empty_ctxt(name));
4871 collect_mod(names, parent);
4874 // danger, shouldn't be ident?
4875 names.push(Ident::from_str("<opaque>"));
4876 collect_mod(names, module.parent.unwrap());
4879 collect_mod(&mut names, module);
4881 if names.is_empty() {
4884 Some(names_to_string(&names.into_iter()
4886 .collect::<Vec<_>>()))
4889 fn err_path_resolution() -> PathResolution {
4890 PathResolution::new(Def::Err)
4893 #[derive(PartialEq,Copy, Clone)]
4894 pub enum MakeGlobMap {
4899 #[derive(Copy, Clone, Debug)]
4901 /// Do not issue the lint
4904 /// This lint applies to some random path like `impl ::foo::Bar`
4905 /// or whatever. In this case, we can take the span of that path.
4908 /// This lint comes from a `use` statement. In this case, what we
4909 /// care about really is the *root* `use` statement; e.g., if we
4910 /// have nested things like `use a::{b, c}`, we care about the
4912 UsePath { root_id: NodeId, root_span: Span },
4914 /// This is the "trait item" from a fully qualified path. For example,
4915 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4916 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4917 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4921 fn node_id(&self) -> Option<NodeId> {
4923 CrateLint::No => None,
4924 CrateLint::SimplePath(id) |
4925 CrateLint::UsePath { root_id: id, .. } |
4926 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4931 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }