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, ParentScope};
85 // NB: This module needs to be declared first so diagnostics are
86 // registered before they are used.
91 mod build_reduced_graph;
94 fn is_known_tool(name: Name) -> bool {
95 ["clippy", "rustfmt"].contains(&&*name.as_str())
98 /// A free importable items suggested in case of resolution failure.
99 struct ImportSuggestion {
103 /// A field or associated item from self type suggested in case of resolution failure.
104 enum AssocSuggestion {
111 struct BindingError {
113 origin: BTreeSet<Span>,
114 target: BTreeSet<Span>,
117 impl PartialOrd for BindingError {
118 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
119 Some(self.cmp(other))
123 impl PartialEq for BindingError {
124 fn eq(&self, other: &BindingError) -> bool {
125 self.name == other.name
129 impl Ord for BindingError {
130 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
131 self.name.cmp(&other.name)
135 enum ResolutionError<'a> {
136 /// error E0401: can't use type parameters from outer function
137 TypeParametersFromOuterFunction(Def),
138 /// error E0403: the name is already used for a type parameter in this type parameter list
139 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
140 /// error E0407: method is not a member of trait
141 MethodNotMemberOfTrait(Name, &'a str),
142 /// error E0437: type is not a member of trait
143 TypeNotMemberOfTrait(Name, &'a str),
144 /// error E0438: const is not a member of trait
145 ConstNotMemberOfTrait(Name, &'a str),
146 /// error E0408: variable `{}` is not bound in all patterns
147 VariableNotBoundInPattern(&'a BindingError),
148 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
149 VariableBoundWithDifferentMode(Name, Span),
150 /// error E0415: identifier is bound more than once in this parameter list
151 IdentifierBoundMoreThanOnceInParameterList(&'a str),
152 /// error E0416: identifier is bound more than once in the same pattern
153 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
154 /// error E0426: use of undeclared label
155 UndeclaredLabel(&'a str, Option<Name>),
156 /// error E0429: `self` imports are only allowed within a { } list
157 SelfImportsOnlyAllowedWithin,
158 /// error E0430: `self` import can only appear once in the list
159 SelfImportCanOnlyAppearOnceInTheList,
160 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
161 SelfImportOnlyInImportListWithNonEmptyPrefix,
162 /// error E0433: failed to resolve
163 FailedToResolve(&'a str),
164 /// error E0434: can't capture dynamic environment in a fn item
165 CannotCaptureDynamicEnvironmentInFnItem,
166 /// error E0435: attempt to use a non-constant value in a constant
167 AttemptToUseNonConstantValueInConstant,
168 /// error E0530: X bindings cannot shadow Ys
169 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
170 /// error E0128: type parameters with a default cannot use forward declared identifiers
171 ForwardDeclaredTyParam,
174 /// Combines an error with provided span and emits it
176 /// This takes the error provided, combines it with the span and any additional spans inside the
177 /// error and emits it.
178 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
180 resolution_error: ResolutionError<'a>) {
181 resolve_struct_error(resolver, span, resolution_error).emit();
184 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
186 resolution_error: ResolutionError<'a>)
187 -> DiagnosticBuilder<'sess> {
188 match resolution_error {
189 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
190 let mut err = struct_span_err!(resolver.session,
193 "can't use type parameters from outer function");
194 err.span_label(span, "use of type variable from outer function");
196 let cm = resolver.session.source_map();
198 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
199 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
200 resolver.definitions.opt_span(def_id)
203 reduce_impl_span_to_impl_keyword(cm, impl_span),
204 "`Self` type implicitly declared here, by this `impl`",
207 match (maybe_trait_defid, maybe_impl_defid) {
209 err.span_label(span, "can't use `Self` here");
212 err.span_label(span, "use a type here instead");
214 (None, None) => bug!("`impl` without trait nor type?"),
218 Def::TyParam(typaram_defid) => {
219 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
220 err.span_label(typaram_span, "type variable from outer function");
224 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
229 // Try to retrieve the span of the function signature and generate a new message with
230 // a local type parameter
231 let sugg_msg = "try using a local type parameter instead";
232 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
233 // Suggest the modification to the user
234 err.span_suggestion_with_applicability(
238 Applicability::MachineApplicable,
240 } else if let Some(sp) = cm.generate_fn_name_span(span) {
241 err.span_label(sp, "try adding a local type parameter in this method instead");
243 err.help("try using a local type parameter instead");
248 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
249 let mut err = struct_span_err!(resolver.session,
252 "the name `{}` is already used for a type parameter \
253 in this type parameter list",
255 err.span_label(span, "already used");
256 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
259 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
260 let mut err = struct_span_err!(resolver.session,
263 "method `{}` is not a member of trait `{}`",
266 err.span_label(span, format!("not a member of trait `{}`", trait_));
269 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
270 let mut err = struct_span_err!(resolver.session,
273 "type `{}` is not a member of trait `{}`",
276 err.span_label(span, format!("not a member of trait `{}`", trait_));
279 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
280 let mut err = struct_span_err!(resolver.session,
283 "const `{}` is not a member of trait `{}`",
286 err.span_label(span, format!("not a member of trait `{}`", trait_));
289 ResolutionError::VariableNotBoundInPattern(binding_error) => {
290 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
291 let msp = MultiSpan::from_spans(target_sp.clone());
292 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
293 let mut err = resolver.session.struct_span_err_with_code(
296 DiagnosticId::Error("E0408".into()),
298 for sp in target_sp {
299 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
301 let origin_sp = binding_error.origin.iter().cloned();
302 for sp in origin_sp {
303 err.span_label(sp, "variable not in all patterns");
307 ResolutionError::VariableBoundWithDifferentMode(variable_name,
308 first_binding_span) => {
309 let mut err = struct_span_err!(resolver.session,
312 "variable `{}` is bound in inconsistent \
313 ways within the same match arm",
315 err.span_label(span, "bound in different ways");
316 err.span_label(first_binding_span, "first binding");
319 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
320 let mut err = struct_span_err!(resolver.session,
323 "identifier `{}` is bound more than once in this parameter list",
325 err.span_label(span, "used as parameter more than once");
328 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
329 let mut err = struct_span_err!(resolver.session,
332 "identifier `{}` is bound more than once in the same pattern",
334 err.span_label(span, "used in a pattern more than once");
337 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
338 let mut err = struct_span_err!(resolver.session,
341 "use of undeclared label `{}`",
343 if let Some(lev_candidate) = lev_candidate {
344 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
346 err.span_label(span, format!("undeclared label `{}`", name));
350 ResolutionError::SelfImportsOnlyAllowedWithin => {
351 struct_span_err!(resolver.session,
355 "`self` imports are only allowed within a { } list")
357 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
358 let mut err = struct_span_err!(resolver.session, span, E0430,
359 "`self` import can only appear once in an import list");
360 err.span_label(span, "can only appear once in an import list");
363 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
364 let mut err = struct_span_err!(resolver.session, span, E0431,
365 "`self` import can only appear in an import list with \
366 a non-empty prefix");
367 err.span_label(span, "can only appear in an import list with a non-empty prefix");
370 ResolutionError::FailedToResolve(msg) => {
371 let mut err = struct_span_err!(resolver.session, span, E0433,
372 "failed to resolve. {}", msg);
373 err.span_label(span, msg);
376 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
377 let mut err = struct_span_err!(resolver.session,
381 "can't capture dynamic environment in a fn item");
382 err.help("use the `|| { ... }` closure form instead");
385 ResolutionError::AttemptToUseNonConstantValueInConstant => {
386 let mut err = struct_span_err!(resolver.session, span, E0435,
387 "attempt to use a non-constant value in a constant");
388 err.span_label(span, "non-constant value");
391 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
392 let shadows_what = PathResolution::new(binding.def()).kind_name();
393 let mut err = struct_span_err!(resolver.session,
396 "{}s cannot shadow {}s", what_binding, shadows_what);
397 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
398 let participle = if binding.is_import() { "imported" } else { "defined" };
399 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
400 err.span_label(binding.span, msg);
403 ResolutionError::ForwardDeclaredTyParam => {
404 let mut err = struct_span_err!(resolver.session, span, E0128,
405 "type parameters with a default cannot use \
406 forward declared identifiers");
408 span, "defaulted type parameters cannot be forward declared".to_string());
414 /// Adjust the impl span so that just the `impl` keyword is taken by removing
415 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
416 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
418 /// Attention: The method used is very fragile since it essentially duplicates the work of the
419 /// parser. If you need to use this function or something similar, please consider updating the
420 /// source_map functions and this function to something more robust.
421 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
422 let impl_span = cm.span_until_char(impl_span, '<');
423 let impl_span = cm.span_until_whitespace(impl_span);
427 #[derive(Copy, Clone, Debug)]
430 binding_mode: BindingMode,
433 /// Map from the name in a pattern to its binding mode.
434 type BindingMap = FxHashMap<Ident, BindingInfo>;
436 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
447 fn descr(self) -> &'static str {
449 PatternSource::Match => "match binding",
450 PatternSource::IfLet => "if let binding",
451 PatternSource::WhileLet => "while let binding",
452 PatternSource::Let => "let binding",
453 PatternSource::For => "for binding",
454 PatternSource::FnParam => "function parameter",
459 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
460 enum AliasPossibility {
465 #[derive(Copy, Clone, Debug)]
466 enum PathSource<'a> {
467 // Type paths `Path`.
469 // Trait paths in bounds or impls.
470 Trait(AliasPossibility),
471 // Expression paths `path`, with optional parent context.
472 Expr(Option<&'a Expr>),
473 // Paths in path patterns `Path`.
475 // Paths in struct expressions and patterns `Path { .. }`.
477 // Paths in tuple struct patterns `Path(..)`.
479 // `m::A::B` in `<T as m::A>::B::C`.
480 TraitItem(Namespace),
481 // Path in `pub(path)`
483 // Path in `use a::b::{...};`
487 impl<'a> PathSource<'a> {
488 fn namespace(self) -> Namespace {
490 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
491 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
492 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
493 PathSource::TraitItem(ns) => ns,
497 fn global_by_default(self) -> bool {
499 PathSource::Visibility | PathSource::ImportPrefix => true,
500 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
501 PathSource::Struct | PathSource::TupleStruct |
502 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
506 fn defer_to_typeck(self) -> bool {
508 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
509 PathSource::Struct | PathSource::TupleStruct => true,
510 PathSource::Trait(_) | PathSource::TraitItem(..) |
511 PathSource::Visibility | PathSource::ImportPrefix => false,
515 fn descr_expected(self) -> &'static str {
517 PathSource::Type => "type",
518 PathSource::Trait(_) => "trait",
519 PathSource::Pat => "unit struct/variant or constant",
520 PathSource::Struct => "struct, variant or union type",
521 PathSource::TupleStruct => "tuple struct/variant",
522 PathSource::Visibility => "module",
523 PathSource::ImportPrefix => "module or enum",
524 PathSource::TraitItem(ns) => match ns {
525 TypeNS => "associated type",
526 ValueNS => "method or associated constant",
527 MacroNS => bug!("associated macro"),
529 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
530 // "function" here means "anything callable" rather than `Def::Fn`,
531 // this is not precise but usually more helpful than just "value".
532 Some(&ExprKind::Call(..)) => "function",
538 fn is_expected(self, def: Def) -> bool {
540 PathSource::Type => match def {
541 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
542 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
543 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
544 Def::Existential(..) |
545 Def::ForeignTy(..) => true,
548 PathSource::Trait(AliasPossibility::No) => match def {
549 Def::Trait(..) => true,
552 PathSource::Trait(AliasPossibility::Maybe) => match def {
553 Def::Trait(..) => true,
554 Def::TraitAlias(..) => true,
557 PathSource::Expr(..) => match def {
558 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
559 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
560 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
561 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
562 Def::SelfCtor(..) => true,
565 PathSource::Pat => match def {
566 Def::StructCtor(_, CtorKind::Const) |
567 Def::VariantCtor(_, CtorKind::Const) |
568 Def::Const(..) | Def::AssociatedConst(..) |
569 Def::SelfCtor(..) => true,
572 PathSource::TupleStruct => match def {
573 Def::StructCtor(_, CtorKind::Fn) |
574 Def::VariantCtor(_, CtorKind::Fn) |
575 Def::SelfCtor(..) => true,
578 PathSource::Struct => match def {
579 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
580 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
583 PathSource::TraitItem(ns) => match def {
584 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
585 Def::AssociatedTy(..) if ns == TypeNS => true,
588 PathSource::ImportPrefix => match def {
589 Def::Mod(..) | Def::Enum(..) => true,
592 PathSource::Visibility => match def {
593 Def::Mod(..) => true,
599 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
600 __diagnostic_used!(E0404);
601 __diagnostic_used!(E0405);
602 __diagnostic_used!(E0412);
603 __diagnostic_used!(E0422);
604 __diagnostic_used!(E0423);
605 __diagnostic_used!(E0425);
606 __diagnostic_used!(E0531);
607 __diagnostic_used!(E0532);
608 __diagnostic_used!(E0573);
609 __diagnostic_used!(E0574);
610 __diagnostic_used!(E0575);
611 __diagnostic_used!(E0576);
612 __diagnostic_used!(E0577);
613 __diagnostic_used!(E0578);
614 match (self, has_unexpected_resolution) {
615 (PathSource::Trait(_), true) => "E0404",
616 (PathSource::Trait(_), false) => "E0405",
617 (PathSource::Type, true) => "E0573",
618 (PathSource::Type, false) => "E0412",
619 (PathSource::Struct, true) => "E0574",
620 (PathSource::Struct, false) => "E0422",
621 (PathSource::Expr(..), true) => "E0423",
622 (PathSource::Expr(..), false) => "E0425",
623 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
624 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
625 (PathSource::TraitItem(..), true) => "E0575",
626 (PathSource::TraitItem(..), false) => "E0576",
627 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
628 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
633 struct UsePlacementFinder {
634 target_module: NodeId,
639 impl UsePlacementFinder {
640 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
641 let mut finder = UsePlacementFinder {
646 visit::walk_crate(&mut finder, krate);
647 (finder.span, finder.found_use)
651 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
654 module: &'tcx ast::Mod,
656 _: &[ast::Attribute],
659 if self.span.is_some() {
662 if node_id != self.target_module {
663 visit::walk_mod(self, module);
666 // find a use statement
667 for item in &module.items {
669 ItemKind::Use(..) => {
670 // don't suggest placing a use before the prelude
671 // import or other generated ones
672 if item.span.ctxt().outer().expn_info().is_none() {
673 self.span = Some(item.span.shrink_to_lo());
674 self.found_use = true;
678 // don't place use before extern crate
679 ItemKind::ExternCrate(_) => {}
680 // but place them before the first other item
681 _ => if self.span.map_or(true, |span| item.span < span ) {
682 if item.span.ctxt().outer().expn_info().is_none() {
683 // don't insert between attributes and an item
684 if item.attrs.is_empty() {
685 self.span = Some(item.span.shrink_to_lo());
687 // find the first attribute on the item
688 for attr in &item.attrs {
689 if self.span.map_or(true, |span| attr.span < span) {
690 self.span = Some(attr.span.shrink_to_lo());
701 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
702 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
703 fn visit_item(&mut self, item: &'tcx Item) {
704 self.resolve_item(item);
706 fn visit_arm(&mut self, arm: &'tcx Arm) {
707 self.resolve_arm(arm);
709 fn visit_block(&mut self, block: &'tcx Block) {
710 self.resolve_block(block);
712 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
713 self.with_constant_rib(|this| {
714 visit::walk_anon_const(this, constant);
717 fn visit_expr(&mut self, expr: &'tcx Expr) {
718 self.resolve_expr(expr, None);
720 fn visit_local(&mut self, local: &'tcx Local) {
721 self.resolve_local(local);
723 fn visit_ty(&mut self, ty: &'tcx Ty) {
725 TyKind::Path(ref qself, ref path) => {
726 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
728 TyKind::ImplicitSelf => {
729 let self_ty = keywords::SelfType.ident();
730 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
731 .map_or(Def::Err, |d| d.def());
732 self.record_def(ty.id, PathResolution::new(def));
736 visit::walk_ty(self, ty);
738 fn visit_poly_trait_ref(&mut self,
739 tref: &'tcx ast::PolyTraitRef,
740 m: &'tcx ast::TraitBoundModifier) {
741 self.smart_resolve_path(tref.trait_ref.ref_id, None,
742 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
743 visit::walk_poly_trait_ref(self, tref, m);
745 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
746 let type_parameters = match foreign_item.node {
747 ForeignItemKind::Fn(_, ref generics) => {
748 HasTypeParameters(generics, ItemRibKind)
750 ForeignItemKind::Static(..) => NoTypeParameters,
751 ForeignItemKind::Ty => NoTypeParameters,
752 ForeignItemKind::Macro(..) => NoTypeParameters,
754 self.with_type_parameter_rib(type_parameters, |this| {
755 visit::walk_foreign_item(this, foreign_item);
758 fn visit_fn(&mut self,
759 function_kind: FnKind<'tcx>,
760 declaration: &'tcx FnDecl,
764 let (rib_kind, asyncness) = match function_kind {
765 FnKind::ItemFn(_, ref header, ..) =>
766 (ItemRibKind, header.asyncness),
767 FnKind::Method(_, ref sig, _, _) =>
768 (TraitOrImplItemRibKind, sig.header.asyncness),
769 FnKind::Closure(_) =>
770 // Async closures aren't resolved through `visit_fn`-- they're
771 // processed separately
772 (ClosureRibKind(node_id), IsAsync::NotAsync),
775 // Create a value rib for the function.
776 self.ribs[ValueNS].push(Rib::new(rib_kind));
778 // Create a label rib for the function.
779 self.label_ribs.push(Rib::new(rib_kind));
781 // Add each argument to the rib.
782 let mut bindings_list = FxHashMap();
783 for argument in &declaration.inputs {
784 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
786 self.visit_ty(&argument.ty);
788 debug!("(resolving function) recorded argument");
790 visit::walk_fn_ret_ty(self, &declaration.output);
792 // Resolve the function body, potentially inside the body of an async closure
793 if let IsAsync::Async { closure_id, .. } = asyncness {
794 let rib_kind = ClosureRibKind(closure_id);
795 self.ribs[ValueNS].push(Rib::new(rib_kind));
796 self.label_ribs.push(Rib::new(rib_kind));
799 match function_kind {
800 FnKind::ItemFn(.., body) |
801 FnKind::Method(.., body) => {
802 self.visit_block(body);
804 FnKind::Closure(body) => {
805 self.visit_expr(body);
809 // Leave the body of the async closure
810 if asyncness.is_async() {
811 self.label_ribs.pop();
812 self.ribs[ValueNS].pop();
815 debug!("(resolving function) leaving function");
817 self.label_ribs.pop();
818 self.ribs[ValueNS].pop();
820 fn visit_generics(&mut self, generics: &'tcx Generics) {
821 // For type parameter defaults, we have to ban access
822 // to following type parameters, as the Substs can only
823 // provide previous type parameters as they're built. We
824 // put all the parameters on the ban list and then remove
825 // them one by one as they are processed and become available.
826 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
827 let mut found_default = false;
828 default_ban_rib.bindings.extend(generics.params.iter()
829 .filter_map(|param| match param.kind {
830 GenericParamKind::Lifetime { .. } => None,
831 GenericParamKind::Type { ref default, .. } => {
832 found_default |= default.is_some();
834 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
841 for param in &generics.params {
843 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
844 GenericParamKind::Type { ref default, .. } => {
845 for bound in ¶m.bounds {
846 self.visit_param_bound(bound);
849 if let Some(ref ty) = default {
850 self.ribs[TypeNS].push(default_ban_rib);
852 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
855 // Allow all following defaults to refer to this type parameter.
856 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
860 for p in &generics.where_clause.predicates {
861 self.visit_where_predicate(p);
866 #[derive(Copy, Clone)]
867 enum TypeParameters<'a, 'b> {
869 HasTypeParameters(// Type parameters.
872 // The kind of the rib used for type parameters.
876 /// The rib kind controls the translation of local
877 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
878 #[derive(Copy, Clone, Debug)]
880 /// No translation needs to be applied.
883 /// We passed through a closure scope at the given node ID.
884 /// Translate upvars as appropriate.
885 ClosureRibKind(NodeId /* func id */),
887 /// We passed through an impl or trait and are now in one of its
888 /// methods or associated types. Allow references to ty params that impl or trait
889 /// binds. Disallow any other upvars (including other ty params that are
891 TraitOrImplItemRibKind,
893 /// We passed through an item scope. Disallow upvars.
896 /// We're in a constant item. Can't refer to dynamic stuff.
899 /// We passed through a module.
900 ModuleRibKind(Module<'a>),
902 /// We passed through a `macro_rules!` statement
903 MacroDefinition(DefId),
905 /// All bindings in this rib are type parameters that can't be used
906 /// from the default of a type parameter because they're not declared
907 /// before said type parameter. Also see the `visit_generics` override.
908 ForwardTyParamBanRibKind,
913 /// A rib represents a scope names can live in. Note that these appear in many places, not just
914 /// around braces. At any place where the list of accessible names (of the given namespace)
915 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
916 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
919 /// Different [rib kinds](enum.RibKind) are transparent for different names.
921 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
922 /// resolving, the name is looked up from inside out.
925 bindings: FxHashMap<Ident, Def>,
930 fn new(kind: RibKind<'a>) -> Rib<'a> {
932 bindings: FxHashMap(),
938 /// An intermediate resolution result.
940 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
941 /// items are visible in their whole block, while defs only from the place they are defined
943 enum LexicalScopeBinding<'a> {
944 Item(&'a NameBinding<'a>),
948 impl<'a> LexicalScopeBinding<'a> {
949 fn item(self) -> Option<&'a NameBinding<'a>> {
951 LexicalScopeBinding::Item(binding) => Some(binding),
956 fn def(self) -> Def {
958 LexicalScopeBinding::Item(binding) => binding.def(),
959 LexicalScopeBinding::Def(def) => def,
964 #[derive(Copy, Clone, Debug)]
965 pub enum ModuleOrUniformRoot<'a> {
969 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
970 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
971 /// but *not* `extern`), in the Rust 2018 edition.
975 #[derive(Clone, Debug)]
976 enum PathResult<'a> {
977 Module(ModuleOrUniformRoot<'a>),
978 NonModule(PathResolution),
980 Failed(Span, String, bool /* is the error from the last segment? */),
984 /// An anonymous module, eg. just a block.
989 /// { // This is an anonymous module
990 /// f(); // This resolves to (2) as we are inside the block.
993 /// f(); // Resolves to (1)
997 /// Any module with a name.
1001 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1002 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1007 /// One node in the tree of modules.
1008 pub struct ModuleData<'a> {
1009 parent: Option<Module<'a>>,
1012 // The def id of the closest normal module (`mod`) ancestor (including this module).
1013 normal_ancestor_id: DefId,
1015 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1016 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>, Option<Def>)>>,
1017 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1018 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1020 // Macro invocations that can expand into items in this module.
1021 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1023 no_implicit_prelude: bool,
1025 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1026 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1028 // Used to memoize the traits in this module for faster searches through all traits in scope.
1029 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1031 // Whether this module is populated. If not populated, any attempt to
1032 // access the children must be preceded with a
1033 // `populate_module_if_necessary` call.
1034 populated: Cell<bool>,
1036 /// Span of the module itself. Used for error reporting.
1042 type Module<'a> = &'a ModuleData<'a>;
1044 impl<'a> ModuleData<'a> {
1045 fn new(parent: Option<Module<'a>>,
1047 normal_ancestor_id: DefId,
1049 span: Span) -> Self {
1054 resolutions: RefCell::new(FxHashMap()),
1055 legacy_macro_resolutions: RefCell::new(Vec::new()),
1056 macro_resolutions: RefCell::new(Vec::new()),
1057 builtin_attrs: RefCell::new(Vec::new()),
1058 unresolved_invocations: RefCell::new(FxHashSet()),
1059 no_implicit_prelude: false,
1060 glob_importers: RefCell::new(Vec::new()),
1061 globs: RefCell::new(Vec::new()),
1062 traits: RefCell::new(None),
1063 populated: Cell::new(normal_ancestor_id.is_local()),
1069 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1070 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1071 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1075 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1076 let resolutions = self.resolutions.borrow();
1077 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1078 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1079 for &(&(ident, ns), &resolution) in resolutions.iter() {
1080 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1084 fn def(&self) -> Option<Def> {
1086 ModuleKind::Def(def, _) => Some(def),
1091 fn def_id(&self) -> Option<DefId> {
1092 self.def().as_ref().map(Def::def_id)
1095 // `self` resolves to the first module ancestor that `is_normal`.
1096 fn is_normal(&self) -> bool {
1098 ModuleKind::Def(Def::Mod(_), _) => true,
1103 fn is_trait(&self) -> bool {
1105 ModuleKind::Def(Def::Trait(_), _) => true,
1110 fn is_local(&self) -> bool {
1111 self.normal_ancestor_id.is_local()
1114 fn nearest_item_scope(&'a self) -> Module<'a> {
1115 if self.is_trait() { self.parent.unwrap() } else { self }
1119 impl<'a> fmt::Debug for ModuleData<'a> {
1120 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1121 write!(f, "{:?}", self.def())
1125 /// Records a possibly-private value, type, or module definition.
1126 #[derive(Clone, Debug)]
1127 pub struct NameBinding<'a> {
1128 kind: NameBindingKind<'a>,
1131 vis: ty::Visibility,
1134 pub trait ToNameBinding<'a> {
1135 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1138 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1139 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1144 #[derive(Clone, Debug)]
1145 enum NameBindingKind<'a> {
1146 Def(Def, /* is_macro_export */ bool),
1149 binding: &'a NameBinding<'a>,
1150 directive: &'a ImportDirective<'a>,
1154 b1: &'a NameBinding<'a>,
1155 b2: &'a NameBinding<'a>,
1159 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1161 struct UseError<'a> {
1162 err: DiagnosticBuilder<'a>,
1163 /// Attach `use` statements for these candidates
1164 candidates: Vec<ImportSuggestion>,
1165 /// The node id of the module to place the use statements in
1167 /// Whether the diagnostic should state that it's "better"
1171 struct AmbiguityError<'a> {
1173 b1: &'a NameBinding<'a>,
1174 b2: &'a NameBinding<'a>,
1177 impl<'a> NameBinding<'a> {
1178 fn module(&self) -> Option<Module<'a>> {
1180 NameBindingKind::Module(module) => Some(module),
1181 NameBindingKind::Import { binding, .. } => binding.module(),
1186 fn def(&self) -> Def {
1188 NameBindingKind::Def(def, _) => def,
1189 NameBindingKind::Module(module) => module.def().unwrap(),
1190 NameBindingKind::Import { binding, .. } => binding.def(),
1191 NameBindingKind::Ambiguity { .. } => Def::Err,
1195 fn def_ignoring_ambiguity(&self) -> Def {
1197 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1198 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1203 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1204 resolver.get_macro(self.def_ignoring_ambiguity())
1207 // We sometimes need to treat variants as `pub` for backwards compatibility
1208 fn pseudo_vis(&self) -> ty::Visibility {
1209 if self.is_variant() && self.def().def_id().is_local() {
1210 ty::Visibility::Public
1216 fn is_variant(&self) -> bool {
1218 NameBindingKind::Def(Def::Variant(..), _) |
1219 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1224 fn is_extern_crate(&self) -> bool {
1226 NameBindingKind::Import {
1227 directive: &ImportDirective {
1228 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1235 fn is_import(&self) -> bool {
1237 NameBindingKind::Import { .. } => true,
1242 fn is_renamed_extern_crate(&self) -> bool {
1243 if let NameBindingKind::Import { directive, ..} = self.kind {
1244 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1251 fn is_glob_import(&self) -> bool {
1253 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1254 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1259 fn is_importable(&self) -> bool {
1261 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1266 fn is_macro_def(&self) -> bool {
1268 NameBindingKind::Def(Def::Macro(..), _) => true,
1273 fn macro_kind(&self) -> Option<MacroKind> {
1274 match self.def_ignoring_ambiguity() {
1275 Def::Macro(_, kind) => Some(kind),
1276 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1281 fn descr(&self) -> &'static str {
1282 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1285 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1286 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1287 // Then this function returns `true` if `self` may emerge from a macro *after* that
1288 // in some later round and screw up our previously found resolution.
1289 // See more detailed explanation in
1290 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1291 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1292 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1293 // Expansions are partially ordered, so "may appear after" is an inversion of
1294 // "certainly appears before or simultaneously" and includes unordered cases.
1295 let self_parent_expansion = self.expansion;
1296 let other_parent_expansion = binding.expansion;
1297 let certainly_before_other_or_simultaneously =
1298 other_parent_expansion.is_descendant_of(self_parent_expansion);
1299 let certainly_before_invoc_or_simultaneously =
1300 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1301 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1305 /// Interns the names of the primitive types.
1307 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1308 /// special handling, since they have no place of origin.
1309 struct PrimitiveTypeTable {
1310 primitive_types: FxHashMap<Name, PrimTy>,
1313 impl PrimitiveTypeTable {
1314 fn new() -> PrimitiveTypeTable {
1315 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1317 table.intern("bool", Bool);
1318 table.intern("char", Char);
1319 table.intern("f32", Float(FloatTy::F32));
1320 table.intern("f64", Float(FloatTy::F64));
1321 table.intern("isize", Int(IntTy::Isize));
1322 table.intern("i8", Int(IntTy::I8));
1323 table.intern("i16", Int(IntTy::I16));
1324 table.intern("i32", Int(IntTy::I32));
1325 table.intern("i64", Int(IntTy::I64));
1326 table.intern("i128", Int(IntTy::I128));
1327 table.intern("str", Str);
1328 table.intern("usize", Uint(UintTy::Usize));
1329 table.intern("u8", Uint(UintTy::U8));
1330 table.intern("u16", Uint(UintTy::U16));
1331 table.intern("u32", Uint(UintTy::U32));
1332 table.intern("u64", Uint(UintTy::U64));
1333 table.intern("u128", Uint(UintTy::U128));
1337 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1338 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1342 /// The main resolver class.
1344 /// This is the visitor that walks the whole crate.
1345 pub struct Resolver<'a, 'b: 'a> {
1346 session: &'a Session,
1349 pub definitions: Definitions,
1351 graph_root: Module<'a>,
1353 prelude: Option<Module<'a>>,
1354 extern_prelude: FxHashSet<Name>,
1356 /// n.b. This is used only for better diagnostics, not name resolution itself.
1357 has_self: FxHashSet<DefId>,
1359 /// Names of fields of an item `DefId` accessible with dot syntax.
1360 /// Used for hints during error reporting.
1361 field_names: FxHashMap<DefId, Vec<Name>>,
1363 /// All imports known to succeed or fail.
1364 determined_imports: Vec<&'a ImportDirective<'a>>,
1366 /// All non-determined imports.
1367 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1369 /// The module that represents the current item scope.
1370 current_module: Module<'a>,
1372 /// The current set of local scopes for types and values.
1373 /// FIXME #4948: Reuse ribs to avoid allocation.
1374 ribs: PerNS<Vec<Rib<'a>>>,
1376 /// The current set of local scopes, for labels.
1377 label_ribs: Vec<Rib<'a>>,
1379 /// The trait that the current context can refer to.
1380 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1382 /// The current self type if inside an impl (used for better errors).
1383 current_self_type: Option<Ty>,
1385 /// The idents for the primitive types.
1386 primitive_type_table: PrimitiveTypeTable,
1389 import_map: ImportMap,
1390 pub freevars: FreevarMap,
1391 freevars_seen: NodeMap<NodeMap<usize>>,
1392 pub export_map: ExportMap,
1393 pub trait_map: TraitMap,
1395 /// A map from nodes to anonymous modules.
1396 /// Anonymous modules are pseudo-modules that are implicitly created around items
1397 /// contained within blocks.
1399 /// For example, if we have this:
1407 /// There will be an anonymous module created around `g` with the ID of the
1408 /// entry block for `f`.
1409 block_map: NodeMap<Module<'a>>,
1410 module_map: FxHashMap<DefId, Module<'a>>,
1411 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1413 pub make_glob_map: bool,
1414 /// Maps imports to the names of items actually imported (this actually maps
1415 /// all imports, but only glob imports are actually interesting).
1416 pub glob_map: GlobMap,
1418 used_imports: FxHashSet<(NodeId, Namespace)>,
1419 pub maybe_unused_trait_imports: NodeSet,
1420 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1422 /// A list of labels as of yet unused. Labels will be removed from this map when
1423 /// they are used (in a `break` or `continue` statement)
1424 pub unused_labels: FxHashMap<NodeId, Span>,
1426 /// privacy errors are delayed until the end in order to deduplicate them
1427 privacy_errors: Vec<PrivacyError<'a>>,
1428 /// ambiguity errors are delayed for deduplication
1429 ambiguity_errors: Vec<AmbiguityError<'a>>,
1430 /// `use` injections are delayed for better placement and deduplication
1431 use_injections: Vec<UseError<'a>>,
1432 /// `use` injections for proc macros wrongly imported with #[macro_use]
1433 proc_mac_errors: Vec<macros::ProcMacError>,
1434 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1435 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1437 arenas: &'a ResolverArenas<'a>,
1438 dummy_binding: &'a NameBinding<'a>,
1440 crate_loader: &'a mut CrateLoader<'b>,
1441 macro_names: FxHashSet<Ident>,
1442 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1443 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1444 pub all_macros: FxHashMap<Name, Def>,
1445 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1446 macro_defs: FxHashMap<Mark, DefId>,
1447 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1448 pub whitelisted_legacy_custom_derives: Vec<Name>,
1449 pub found_unresolved_macro: bool,
1451 /// List of crate local macros that we need to warn about as being unused.
1452 /// Right now this only includes macro_rules! macros, and macros 2.0.
1453 unused_macros: FxHashSet<DefId>,
1455 /// Maps the `Mark` of an expansion to its containing module or block.
1456 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1458 /// Avoid duplicated errors for "name already defined".
1459 name_already_seen: FxHashMap<Name, Span>,
1461 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1462 warned_proc_macros: FxHashSet<Name>,
1464 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1466 /// This table maps struct IDs into struct constructor IDs,
1467 /// it's not used during normal resolution, only for better error reporting.
1468 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1470 /// Only used for better errors on `fn(): fn()`
1471 current_type_ascription: Vec<Span>,
1473 injected_crate: Option<Module<'a>>,
1475 /// Only supposed to be used by rustdoc, otherwise should be false.
1476 pub ignore_extern_prelude_feature: bool,
1479 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1480 pub struct ResolverArenas<'a> {
1481 modules: arena::TypedArena<ModuleData<'a>>,
1482 local_modules: RefCell<Vec<Module<'a>>>,
1483 name_bindings: arena::TypedArena<NameBinding<'a>>,
1484 import_directives: arena::TypedArena<ImportDirective<'a>>,
1485 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1486 invocation_data: arena::TypedArena<InvocationData<'a>>,
1487 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1490 impl<'a> ResolverArenas<'a> {
1491 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1492 let module = self.modules.alloc(module);
1493 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1494 self.local_modules.borrow_mut().push(module);
1498 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1499 self.local_modules.borrow()
1501 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1502 self.name_bindings.alloc(name_binding)
1504 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1505 -> &'a ImportDirective {
1506 self.import_directives.alloc(import_directive)
1508 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1509 self.name_resolutions.alloc(Default::default())
1511 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1512 -> &'a InvocationData<'a> {
1513 self.invocation_data.alloc(expansion_data)
1515 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1516 self.legacy_bindings.alloc(binding)
1520 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1521 fn parent(self, id: DefId) -> Option<DefId> {
1523 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1524 _ => self.cstore.def_key(id).parent,
1525 }.map(|index| DefId { index, ..id })
1529 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1530 /// the resolver is no longer needed as all the relevant information is inline.
1531 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1532 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1533 self.resolve_hir_path_cb(path, is_value,
1534 |resolver, span, error| resolve_error(resolver, span, error))
1537 fn resolve_str_path(
1540 crate_root: Option<&str>,
1541 components: &[&str],
1542 args: Option<P<hir::GenericArgs>>,
1545 let mut segments = iter::once(keywords::CrateRoot.ident())
1547 crate_root.into_iter()
1548 .chain(components.iter().cloned())
1549 .map(Ident::from_str)
1550 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1552 if let Some(args) = args {
1553 let ident = segments.last().unwrap().ident;
1554 *segments.last_mut().unwrap() = hir::PathSegment {
1561 let mut path = hir::Path {
1564 segments: segments.into(),
1567 self.resolve_hir_path(&mut path, is_value);
1571 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1572 self.def_map.get(&id).cloned()
1575 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1576 self.import_map.get(&id).cloned().unwrap_or_default()
1579 fn definitions(&mut self) -> &mut Definitions {
1580 &mut self.definitions
1584 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1585 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1586 /// isn't something that can be returned because it can't be made to live that long,
1587 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1588 /// just that an error occurred.
1589 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1590 -> Result<hir::Path, ()> {
1592 let mut errored = false;
1594 let mut path = if path_str.starts_with("::") {
1598 segments: iter::once(keywords::CrateRoot.ident()).chain({
1599 path_str.split("::").skip(1).map(Ident::from_str)
1600 }).map(hir::PathSegment::from_ident).collect(),
1606 segments: path_str.split("::").map(Ident::from_str)
1607 .map(hir::PathSegment::from_ident).collect(),
1610 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1611 if errored || path.def == Def::Err {
1618 /// resolve_hir_path, but takes a callback in case there was an error
1619 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1620 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1622 let namespace = if is_value { ValueNS } else { TypeNS };
1623 let hir::Path { ref segments, span, ref mut def } = *path;
1624 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1625 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1626 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1627 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1628 *def = module.def().unwrap(),
1629 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1630 *def = path_res.base_def(),
1631 PathResult::NonModule(..) => match self.resolve_path(
1639 PathResult::Failed(span, msg, _) => {
1640 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1644 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1645 PathResult::Indeterminate => unreachable!(),
1646 PathResult::Failed(span, msg, _) => {
1647 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1653 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1654 pub fn new(session: &'a Session,
1658 make_glob_map: MakeGlobMap,
1659 crate_loader: &'a mut CrateLoader<'crateloader>,
1660 arenas: &'a ResolverArenas<'a>)
1661 -> Resolver<'a, 'crateloader> {
1662 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1663 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1664 let graph_root = arenas.alloc_module(ModuleData {
1665 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1666 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1668 let mut module_map = FxHashMap();
1669 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1671 let mut definitions = Definitions::new();
1672 DefCollector::new(&mut definitions, Mark::root())
1673 .collect_root(crate_name, session.local_crate_disambiguator());
1675 let mut extern_prelude: FxHashSet<Name> =
1676 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1678 // HACK(eddyb) this ignore the `no_{core,std}` attributes.
1679 // FIXME(eddyb) warn (elsewhere) if core/std is used with `no_{core,std}`.
1680 // if !attr::contains_name(&krate.attrs, "no_core") {
1681 // if !attr::contains_name(&krate.attrs, "no_std") {
1682 extern_prelude.insert(Symbol::intern("core"));
1683 extern_prelude.insert(Symbol::intern("std"));
1684 extern_prelude.insert(Symbol::intern("meta"));
1686 let mut invocations = FxHashMap();
1687 invocations.insert(Mark::root(),
1688 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1690 let mut macro_defs = FxHashMap();
1691 macro_defs.insert(Mark::root(), root_def_id);
1700 // The outermost module has def ID 0; this is not reflected in the
1706 has_self: FxHashSet(),
1707 field_names: FxHashMap(),
1709 determined_imports: Vec::new(),
1710 indeterminate_imports: Vec::new(),
1712 current_module: graph_root,
1714 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1715 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1716 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1718 label_ribs: Vec::new(),
1720 current_trait_ref: None,
1721 current_self_type: None,
1723 primitive_type_table: PrimitiveTypeTable::new(),
1726 import_map: NodeMap(),
1727 freevars: NodeMap(),
1728 freevars_seen: NodeMap(),
1729 export_map: FxHashMap(),
1730 trait_map: NodeMap(),
1732 block_map: NodeMap(),
1733 extern_module_map: FxHashMap(),
1735 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1736 glob_map: NodeMap(),
1738 used_imports: FxHashSet(),
1739 maybe_unused_trait_imports: NodeSet(),
1740 maybe_unused_extern_crates: Vec::new(),
1742 unused_labels: FxHashMap(),
1744 privacy_errors: Vec::new(),
1745 ambiguity_errors: Vec::new(),
1746 use_injections: Vec::new(),
1747 proc_mac_errors: Vec::new(),
1748 macro_expanded_macro_export_errors: BTreeSet::new(),
1751 dummy_binding: arenas.alloc_name_binding(NameBinding {
1752 kind: NameBindingKind::Def(Def::Err, false),
1753 expansion: Mark::root(),
1755 vis: ty::Visibility::Public,
1759 macro_names: FxHashSet(),
1760 builtin_macros: FxHashMap(),
1761 macro_use_prelude: FxHashMap(),
1762 all_macros: FxHashMap(),
1763 macro_map: FxHashMap(),
1766 local_macro_def_scopes: FxHashMap(),
1767 name_already_seen: FxHashMap(),
1768 whitelisted_legacy_custom_derives: Vec::new(),
1769 warned_proc_macros: FxHashSet(),
1770 potentially_unused_imports: Vec::new(),
1771 struct_constructors: DefIdMap(),
1772 found_unresolved_macro: false,
1773 unused_macros: FxHashSet(),
1774 current_type_ascription: Vec::new(),
1775 injected_crate: None,
1776 ignore_extern_prelude_feature: false,
1780 pub fn arenas() -> ResolverArenas<'a> {
1782 modules: arena::TypedArena::new(),
1783 local_modules: RefCell::new(Vec::new()),
1784 name_bindings: arena::TypedArena::new(),
1785 import_directives: arena::TypedArena::new(),
1786 name_resolutions: arena::TypedArena::new(),
1787 invocation_data: arena::TypedArena::new(),
1788 legacy_bindings: arena::TypedArena::new(),
1792 /// Runs the function on each namespace.
1793 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1799 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1801 match self.macro_defs.get(&ctxt.outer()) {
1802 Some(&def_id) => return def_id,
1803 None => ctxt.remove_mark(),
1808 /// Entry point to crate resolution.
1809 pub fn resolve_crate(&mut self, krate: &Crate) {
1810 ImportResolver { resolver: self }.finalize_imports();
1811 self.current_module = self.graph_root;
1812 self.finalize_current_module_macro_resolutions();
1814 visit::walk_crate(self, krate);
1816 check_unused::check_crate(self, krate);
1817 self.report_errors(krate);
1818 self.crate_loader.postprocess(krate);
1825 normal_ancestor_id: DefId,
1829 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1830 self.arenas.alloc_module(module)
1833 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1834 -> bool /* true if an error was reported */ {
1835 match binding.kind {
1836 NameBindingKind::Import { directive, binding, ref used }
1839 directive.used.set(true);
1840 self.used_imports.insert((directive.id, ns));
1841 self.add_to_glob_map(directive.id, ident);
1842 self.record_use(ident, ns, binding)
1844 NameBindingKind::Import { .. } => false,
1845 NameBindingKind::Ambiguity { b1, b2 } => {
1846 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1853 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1854 if self.make_glob_map {
1855 self.glob_map.entry(id).or_default().insert(ident.name);
1859 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1860 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1861 /// `ident` in the first scope that defines it (or None if no scopes define it).
1863 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1864 /// the items are defined in the block. For example,
1867 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1870 /// g(); // This resolves to the local variable `g` since it shadows the item.
1874 /// Invariant: This must only be called during main resolution, not during
1875 /// import resolution.
1876 fn resolve_ident_in_lexical_scope(&mut self,
1879 record_used_id: Option<NodeId>,
1881 -> Option<LexicalScopeBinding<'a>> {
1882 let record_used = record_used_id.is_some();
1883 assert!(ns == TypeNS || ns == ValueNS);
1885 ident.span = if ident.name == keywords::SelfType.name() {
1886 // FIXME(jseyfried) improve `Self` hygiene
1887 ident.span.with_ctxt(SyntaxContext::empty())
1892 ident = ident.modern_and_legacy();
1895 // Walk backwards up the ribs in scope.
1896 let mut module = self.graph_root;
1897 for i in (0 .. self.ribs[ns].len()).rev() {
1898 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1899 // The ident resolves to a type parameter or local variable.
1900 return Some(LexicalScopeBinding::Def(
1901 self.adjust_local_def(ns, i, def, record_used, path_span)
1905 module = match self.ribs[ns][i].kind {
1906 ModuleRibKind(module) => module,
1907 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1908 // If an invocation of this macro created `ident`, give up on `ident`
1909 // and switch to `ident`'s source from the macro definition.
1910 ident.span.remove_mark();
1916 let item = self.resolve_ident_in_module_unadjusted(
1917 ModuleOrUniformRoot::Module(module),
1924 if let Ok(binding) = item {
1925 // The ident resolves to an item.
1926 return Some(LexicalScopeBinding::Item(binding));
1930 ModuleKind::Block(..) => {}, // We can see through blocks
1935 ident.span = ident.span.modern();
1936 let mut poisoned = None;
1938 let opt_module = if let Some(node_id) = record_used_id {
1939 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1940 node_id, &mut poisoned)
1942 self.hygienic_lexical_parent(module, &mut ident.span)
1944 module = unwrap_or!(opt_module, break);
1945 let orig_current_module = self.current_module;
1946 self.current_module = module; // Lexical resolutions can never be a privacy error.
1947 let result = self.resolve_ident_in_module_unadjusted(
1948 ModuleOrUniformRoot::Module(module),
1955 self.current_module = orig_current_module;
1959 if let Some(node_id) = poisoned {
1960 self.session.buffer_lint_with_diagnostic(
1961 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1962 node_id, ident.span,
1963 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1964 lint::builtin::BuiltinLintDiagnostics::
1965 ProcMacroDeriveResolutionFallback(ident.span),
1968 return Some(LexicalScopeBinding::Item(binding))
1970 Err(Determined) => continue,
1971 Err(Undetermined) =>
1972 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1976 if !module.no_implicit_prelude {
1977 // `record_used` means that we don't try to load crates during speculative resolution
1978 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1979 if !self.session.features_untracked().extern_prelude &&
1980 !self.ignore_extern_prelude_feature {
1981 feature_err(&self.session.parse_sess, "extern_prelude",
1982 ident.span, GateIssue::Language,
1983 "access to extern crates through prelude is experimental").emit();
1986 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1987 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1988 self.populate_module_if_necessary(&crate_root);
1990 let binding = (crate_root, ty::Visibility::Public,
1991 ident.span, Mark::root()).to_name_binding(self.arenas);
1992 return Some(LexicalScopeBinding::Item(binding));
1994 if ns == TypeNS && is_known_tool(ident.name) {
1995 let binding = (Def::ToolMod, ty::Visibility::Public,
1996 ident.span, Mark::root()).to_name_binding(self.arenas);
1997 return Some(LexicalScopeBinding::Item(binding));
1999 if let Some(prelude) = self.prelude {
2000 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2001 ModuleOrUniformRoot::Module(prelude),
2008 return Some(LexicalScopeBinding::Item(binding));
2016 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2017 -> Option<Module<'a>> {
2018 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2019 return Some(self.macro_def_scope(span.remove_mark()));
2022 if let ModuleKind::Block(..) = module.kind {
2023 return Some(module.parent.unwrap());
2029 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2030 span: &mut Span, node_id: NodeId,
2031 poisoned: &mut Option<NodeId>)
2032 -> Option<Module<'a>> {
2033 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2037 // We need to support the next case under a deprecation warning
2040 // ---- begin: this comes from a proc macro derive
2041 // mod implementation_details {
2042 // // Note that `MyStruct` is not in scope here.
2043 // impl SomeTrait for MyStruct { ... }
2047 // So we have to fall back to the module's parent during lexical resolution in this case.
2048 if let Some(parent) = module.parent {
2049 // Inner module is inside the macro, parent module is outside of the macro.
2050 if module.expansion != parent.expansion &&
2051 module.expansion.is_descendant_of(parent.expansion) {
2052 // The macro is a proc macro derive
2053 if module.expansion.looks_like_proc_macro_derive() {
2054 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2055 *poisoned = Some(node_id);
2056 return module.parent;
2065 fn resolve_ident_in_module(&mut self,
2066 module: ModuleOrUniformRoot<'a>,
2071 -> Result<&'a NameBinding<'a>, Determinacy> {
2072 ident.span = ident.span.modern();
2073 let orig_current_module = self.current_module;
2074 if let ModuleOrUniformRoot::Module(module) = module {
2075 if let Some(def) = ident.span.adjust(module.expansion) {
2076 self.current_module = self.macro_def_scope(def);
2079 let result = self.resolve_ident_in_module_unadjusted(
2080 module, ident, ns, false, record_used, span,
2082 self.current_module = orig_current_module;
2086 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2087 let mut ctxt = ident.span.ctxt();
2088 let mark = if ident.name == keywords::DollarCrate.name() {
2089 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2090 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2091 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2092 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2093 // definitions actually produced by `macro` and `macro` definitions produced by
2094 // `macro_rules!`, but at least such configurations are not stable yet.
2095 ctxt = ctxt.modern_and_legacy();
2096 let mut iter = ctxt.marks().into_iter().rev().peekable();
2097 let mut result = None;
2098 // Find the last modern mark from the end if it exists.
2099 while let Some(&(mark, transparency)) = iter.peek() {
2100 if transparency == Transparency::Opaque {
2101 result = Some(mark);
2107 // Then find the last legacy mark from the end if it exists.
2108 for (mark, transparency) in iter {
2109 if transparency == Transparency::SemiTransparent {
2110 result = Some(mark);
2117 ctxt = ctxt.modern();
2118 ctxt.adjust(Mark::root())
2120 let module = match mark {
2121 Some(def) => self.macro_def_scope(def),
2122 None => return self.graph_root,
2124 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2127 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2128 let mut module = self.get_module(module.normal_ancestor_id);
2129 while module.span.ctxt().modern() != *ctxt {
2130 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2131 module = self.get_module(parent.normal_ancestor_id);
2138 // We maintain a list of value ribs and type ribs.
2140 // Simultaneously, we keep track of the current position in the module
2141 // graph in the `current_module` pointer. When we go to resolve a name in
2142 // the value or type namespaces, we first look through all the ribs and
2143 // then query the module graph. When we resolve a name in the module
2144 // namespace, we can skip all the ribs (since nested modules are not
2145 // allowed within blocks in Rust) and jump straight to the current module
2148 // Named implementations are handled separately. When we find a method
2149 // call, we consult the module node to find all of the implementations in
2150 // scope. This information is lazily cached in the module node. We then
2151 // generate a fake "implementation scope" containing all the
2152 // implementations thus found, for compatibility with old resolve pass.
2154 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2155 where F: FnOnce(&mut Resolver) -> T
2157 let id = self.definitions.local_def_id(id);
2158 let module = self.module_map.get(&id).cloned(); // clones a reference
2159 if let Some(module) = module {
2160 // Move down in the graph.
2161 let orig_module = replace(&mut self.current_module, module);
2162 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2163 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2165 self.finalize_current_module_macro_resolutions();
2168 self.current_module = orig_module;
2169 self.ribs[ValueNS].pop();
2170 self.ribs[TypeNS].pop();
2177 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2178 /// is returned by the given predicate function
2180 /// Stops after meeting a closure.
2181 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2182 where P: Fn(&Rib, Ident) -> Option<R>
2184 for rib in self.label_ribs.iter().rev() {
2187 // If an invocation of this macro created `ident`, give up on `ident`
2188 // and switch to `ident`'s source from the macro definition.
2189 MacroDefinition(def) => {
2190 if def == self.macro_def(ident.span.ctxt()) {
2191 ident.span.remove_mark();
2195 // Do not resolve labels across function boundary
2199 let r = pred(rib, ident);
2207 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2208 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2209 let item_def_id = this.definitions.local_def_id(item.id);
2210 if this.session.features_untracked().self_in_typedefs {
2211 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2212 visit::walk_item(this, item);
2215 visit::walk_item(this, item);
2220 fn resolve_item(&mut self, item: &Item) {
2221 let name = item.ident.name;
2222 debug!("(resolving item) resolving {}", name);
2225 ItemKind::Ty(_, ref generics) |
2226 ItemKind::Fn(_, _, ref generics, _) |
2227 ItemKind::Existential(_, ref generics) => {
2228 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2229 |this| visit::walk_item(this, item));
2232 ItemKind::Enum(_, ref generics) |
2233 ItemKind::Struct(_, ref generics) |
2234 ItemKind::Union(_, ref generics) => {
2235 self.resolve_adt(item, generics);
2238 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2239 self.resolve_implementation(generics,
2245 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2246 // Create a new rib for the trait-wide type parameters.
2247 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2248 let local_def_id = this.definitions.local_def_id(item.id);
2249 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2250 this.visit_generics(generics);
2251 walk_list!(this, visit_param_bound, bounds);
2253 for trait_item in trait_items {
2254 let type_parameters = HasTypeParameters(&trait_item.generics,
2255 TraitOrImplItemRibKind);
2256 this.with_type_parameter_rib(type_parameters, |this| {
2257 match trait_item.node {
2258 TraitItemKind::Const(ref ty, ref default) => {
2261 // Only impose the restrictions of
2262 // ConstRibKind for an actual constant
2263 // expression in a provided default.
2264 if let Some(ref expr) = *default{
2265 this.with_constant_rib(|this| {
2266 this.visit_expr(expr);
2270 TraitItemKind::Method(_, _) => {
2271 visit::walk_trait_item(this, trait_item)
2273 TraitItemKind::Type(..) => {
2274 visit::walk_trait_item(this, trait_item)
2276 TraitItemKind::Macro(_) => {
2277 panic!("unexpanded macro in resolve!")
2286 ItemKind::TraitAlias(ref generics, ref bounds) => {
2287 // Create a new rib for the trait-wide type parameters.
2288 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2289 let local_def_id = this.definitions.local_def_id(item.id);
2290 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2291 this.visit_generics(generics);
2292 walk_list!(this, visit_param_bound, bounds);
2297 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2298 self.with_scope(item.id, |this| {
2299 visit::walk_item(this, item);
2303 ItemKind::Static(ref ty, _, ref expr) |
2304 ItemKind::Const(ref ty, ref expr) => {
2305 self.with_item_rib(|this| {
2307 this.with_constant_rib(|this| {
2308 this.visit_expr(expr);
2313 ItemKind::Use(ref use_tree) => {
2314 // Imports are resolved as global by default, add starting root segment.
2316 segments: use_tree.prefix.make_root().into_iter().collect(),
2317 span: use_tree.span,
2319 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2322 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2323 // do nothing, these are just around to be encoded
2326 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2330 /// For the most part, use trees are desugared into `ImportDirective` instances
2331 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2332 /// there is one special case we handle here: an empty nested import like
2333 /// `a::{b::{}}`, which desugares into...no import directives.
2334 fn resolve_use_tree(
2339 use_tree: &ast::UseTree,
2342 match use_tree.kind {
2343 ast::UseTreeKind::Nested(ref items) => {
2345 segments: prefix.segments
2347 .chain(use_tree.prefix.segments.iter())
2350 span: prefix.span.to(use_tree.prefix.span),
2353 if items.len() == 0 {
2354 // Resolve prefix of an import with empty braces (issue #28388).
2355 self.smart_resolve_path_with_crate_lint(
2359 PathSource::ImportPrefix,
2360 CrateLint::UsePath { root_id, root_span },
2363 for &(ref tree, nested_id) in items {
2364 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2368 ast::UseTreeKind::Simple(..) => {},
2369 ast::UseTreeKind::Glob => {},
2373 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2374 where F: FnOnce(&mut Resolver)
2376 match type_parameters {
2377 HasTypeParameters(generics, rib_kind) => {
2378 let mut function_type_rib = Rib::new(rib_kind);
2379 let mut seen_bindings = FxHashMap();
2380 for param in &generics.params {
2382 GenericParamKind::Lifetime { .. } => {}
2383 GenericParamKind::Type { .. } => {
2384 let ident = param.ident.modern();
2385 debug!("with_type_parameter_rib: {}", param.id);
2387 if seen_bindings.contains_key(&ident) {
2388 let span = seen_bindings.get(&ident).unwrap();
2389 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2393 resolve_error(self, param.ident.span, err);
2395 seen_bindings.entry(ident).or_insert(param.ident.span);
2397 // Plain insert (no renaming).
2398 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2399 function_type_rib.bindings.insert(ident, def);
2400 self.record_def(param.id, PathResolution::new(def));
2404 self.ribs[TypeNS].push(function_type_rib);
2407 NoTypeParameters => {
2414 if let HasTypeParameters(..) = type_parameters {
2415 self.ribs[TypeNS].pop();
2419 fn with_label_rib<F>(&mut self, f: F)
2420 where F: FnOnce(&mut Resolver)
2422 self.label_ribs.push(Rib::new(NormalRibKind));
2424 self.label_ribs.pop();
2427 fn with_item_rib<F>(&mut self, f: F)
2428 where F: FnOnce(&mut Resolver)
2430 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2431 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2433 self.ribs[TypeNS].pop();
2434 self.ribs[ValueNS].pop();
2437 fn with_constant_rib<F>(&mut self, f: F)
2438 where F: FnOnce(&mut Resolver)
2440 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2441 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2443 self.label_ribs.pop();
2444 self.ribs[ValueNS].pop();
2447 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2448 where F: FnOnce(&mut Resolver) -> T
2450 // Handle nested impls (inside fn bodies)
2451 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2452 let result = f(self);
2453 self.current_self_type = previous_value;
2457 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2458 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2459 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2461 let mut new_val = None;
2462 let mut new_id = None;
2463 if let Some(trait_ref) = opt_trait_ref {
2464 let path: Vec<_> = trait_ref.path.segments.iter()
2465 .map(|seg| seg.ident)
2467 let def = self.smart_resolve_path_fragment(
2471 trait_ref.path.span,
2472 PathSource::Trait(AliasPossibility::No),
2473 CrateLint::SimplePath(trait_ref.ref_id),
2475 if def != Def::Err {
2476 new_id = Some(def.def_id());
2477 let span = trait_ref.path.span;
2478 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2485 CrateLint::SimplePath(trait_ref.ref_id),
2488 new_val = Some((module, trait_ref.clone()));
2492 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2493 let result = f(self, new_id);
2494 self.current_trait_ref = original_trait_ref;
2498 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2499 where F: FnOnce(&mut Resolver)
2501 let mut self_type_rib = Rib::new(NormalRibKind);
2503 // plain insert (no renaming, types are not currently hygienic....)
2504 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2505 self.ribs[TypeNS].push(self_type_rib);
2507 self.ribs[TypeNS].pop();
2510 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2511 where F: FnOnce(&mut Resolver)
2513 let self_def = Def::SelfCtor(impl_id);
2514 let mut self_type_rib = Rib::new(NormalRibKind);
2515 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2516 self.ribs[ValueNS].push(self_type_rib);
2518 self.ribs[ValueNS].pop();
2521 fn resolve_implementation(&mut self,
2522 generics: &Generics,
2523 opt_trait_reference: &Option<TraitRef>,
2526 impl_items: &[ImplItem]) {
2527 // If applicable, create a rib for the type parameters.
2528 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2529 // Dummy self type for better errors if `Self` is used in the trait path.
2530 this.with_self_rib(Def::SelfTy(None, None), |this| {
2531 // Resolve the trait reference, if necessary.
2532 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2533 let item_def_id = this.definitions.local_def_id(item_id);
2534 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2535 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2536 // Resolve type arguments in the trait path.
2537 visit::walk_trait_ref(this, trait_ref);
2539 // Resolve the self type.
2540 this.visit_ty(self_type);
2541 // Resolve the type parameters.
2542 this.visit_generics(generics);
2543 // Resolve the items within the impl.
2544 this.with_current_self_type(self_type, |this| {
2545 this.with_self_struct_ctor_rib(item_def_id, |this| {
2546 for impl_item in impl_items {
2547 this.resolve_visibility(&impl_item.vis);
2549 // We also need a new scope for the impl item type parameters.
2550 let type_parameters = HasTypeParameters(&impl_item.generics,
2551 TraitOrImplItemRibKind);
2552 this.with_type_parameter_rib(type_parameters, |this| {
2553 use self::ResolutionError::*;
2554 match impl_item.node {
2555 ImplItemKind::Const(..) => {
2556 // If this is a trait impl, ensure the const
2558 this.check_trait_item(impl_item.ident,
2561 |n, s| ConstNotMemberOfTrait(n, s));
2562 this.with_constant_rib(|this|
2563 visit::walk_impl_item(this, impl_item)
2566 ImplItemKind::Method(..) => {
2567 // If this is a trait impl, ensure the method
2569 this.check_trait_item(impl_item.ident,
2572 |n, s| MethodNotMemberOfTrait(n, s));
2574 visit::walk_impl_item(this, impl_item);
2576 ImplItemKind::Type(ref ty) => {
2577 // If this is a trait impl, ensure the type
2579 this.check_trait_item(impl_item.ident,
2582 |n, s| TypeNotMemberOfTrait(n, s));
2586 ImplItemKind::Existential(ref bounds) => {
2587 // If this is a trait impl, ensure the type
2589 this.check_trait_item(impl_item.ident,
2592 |n, s| TypeNotMemberOfTrait(n, s));
2594 for bound in bounds {
2595 this.visit_param_bound(bound);
2598 ImplItemKind::Macro(_) =>
2599 panic!("unexpanded macro in resolve!"),
2611 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2612 where F: FnOnce(Name, &str) -> ResolutionError
2614 // If there is a TraitRef in scope for an impl, then the method must be in the
2616 if let Some((module, _)) = self.current_trait_ref {
2617 if self.resolve_ident_in_module(
2618 ModuleOrUniformRoot::Module(module),
2624 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2625 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2630 fn resolve_local(&mut self, local: &Local) {
2631 // Resolve the type.
2632 walk_list!(self, visit_ty, &local.ty);
2634 // Resolve the initializer.
2635 walk_list!(self, visit_expr, &local.init);
2637 // Resolve the pattern.
2638 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2641 // build a map from pattern identifiers to binding-info's.
2642 // this is done hygienically. This could arise for a macro
2643 // that expands into an or-pattern where one 'x' was from the
2644 // user and one 'x' came from the macro.
2645 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2646 let mut binding_map = FxHashMap();
2648 pat.walk(&mut |pat| {
2649 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2650 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2651 Some(Def::Local(..)) => true,
2654 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2655 binding_map.insert(ident, binding_info);
2664 // check that all of the arms in an or-pattern have exactly the
2665 // same set of bindings, with the same binding modes for each.
2666 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2667 if pats.is_empty() {
2671 let mut missing_vars = FxHashMap();
2672 let mut inconsistent_vars = FxHashMap();
2673 for (i, p) in pats.iter().enumerate() {
2674 let map_i = self.binding_mode_map(&p);
2676 for (j, q) in pats.iter().enumerate() {
2681 let map_j = self.binding_mode_map(&q);
2682 for (&key, &binding_i) in &map_i {
2683 if map_j.len() == 0 { // Account for missing bindings when
2684 let binding_error = missing_vars // map_j has none.
2686 .or_insert(BindingError {
2688 origin: BTreeSet::new(),
2689 target: BTreeSet::new(),
2691 binding_error.origin.insert(binding_i.span);
2692 binding_error.target.insert(q.span);
2694 for (&key_j, &binding_j) in &map_j {
2695 match map_i.get(&key_j) {
2696 None => { // missing binding
2697 let binding_error = missing_vars
2699 .or_insert(BindingError {
2701 origin: BTreeSet::new(),
2702 target: BTreeSet::new(),
2704 binding_error.origin.insert(binding_j.span);
2705 binding_error.target.insert(p.span);
2707 Some(binding_i) => { // check consistent binding
2708 if binding_i.binding_mode != binding_j.binding_mode {
2711 .or_insert((binding_j.span, binding_i.span));
2719 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2720 missing_vars.sort();
2721 for (_, v) in missing_vars {
2723 *v.origin.iter().next().unwrap(),
2724 ResolutionError::VariableNotBoundInPattern(v));
2726 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2727 inconsistent_vars.sort();
2728 for (name, v) in inconsistent_vars {
2729 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2733 fn resolve_arm(&mut self, arm: &Arm) {
2734 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2736 let mut bindings_list = FxHashMap();
2737 for pattern in &arm.pats {
2738 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2741 // This has to happen *after* we determine which pat_idents are variants
2742 self.check_consistent_bindings(&arm.pats);
2745 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2748 self.visit_expr(&arm.body);
2750 self.ribs[ValueNS].pop();
2753 fn resolve_block(&mut self, block: &Block) {
2754 debug!("(resolving block) entering block");
2755 // Move down in the graph, if there's an anonymous module rooted here.
2756 let orig_module = self.current_module;
2757 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2759 let mut num_macro_definition_ribs = 0;
2760 if let Some(anonymous_module) = anonymous_module {
2761 debug!("(resolving block) found anonymous module, moving down");
2762 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2763 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2764 self.current_module = anonymous_module;
2765 self.finalize_current_module_macro_resolutions();
2767 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2770 // Descend into the block.
2771 for stmt in &block.stmts {
2772 if let ast::StmtKind::Item(ref item) = stmt.node {
2773 if let ast::ItemKind::MacroDef(..) = item.node {
2774 num_macro_definition_ribs += 1;
2775 let def = self.definitions.local_def_id(item.id);
2776 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2777 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2781 self.visit_stmt(stmt);
2785 self.current_module = orig_module;
2786 for _ in 0 .. num_macro_definition_ribs {
2787 self.ribs[ValueNS].pop();
2788 self.label_ribs.pop();
2790 self.ribs[ValueNS].pop();
2791 if anonymous_module.is_some() {
2792 self.ribs[TypeNS].pop();
2794 debug!("(resolving block) leaving block");
2797 fn fresh_binding(&mut self,
2800 outer_pat_id: NodeId,
2801 pat_src: PatternSource,
2802 bindings: &mut FxHashMap<Ident, NodeId>)
2804 // Add the binding to the local ribs, if it
2805 // doesn't already exist in the bindings map. (We
2806 // must not add it if it's in the bindings map
2807 // because that breaks the assumptions later
2808 // passes make about or-patterns.)
2809 let ident = ident.modern_and_legacy();
2810 let mut def = Def::Local(pat_id);
2811 match bindings.get(&ident).cloned() {
2812 Some(id) if id == outer_pat_id => {
2813 // `Variant(a, a)`, error
2817 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2821 Some(..) if pat_src == PatternSource::FnParam => {
2822 // `fn f(a: u8, a: u8)`, error
2826 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2830 Some(..) if pat_src == PatternSource::Match ||
2831 pat_src == PatternSource::IfLet ||
2832 pat_src == PatternSource::WhileLet => {
2833 // `Variant1(a) | Variant2(a)`, ok
2834 // Reuse definition from the first `a`.
2835 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2838 span_bug!(ident.span, "two bindings with the same name from \
2839 unexpected pattern source {:?}", pat_src);
2842 // A completely fresh binding, add to the lists if it's valid.
2843 if ident.name != keywords::Invalid.name() {
2844 bindings.insert(ident, outer_pat_id);
2845 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2850 PathResolution::new(def)
2853 fn resolve_pattern(&mut self,
2855 pat_src: PatternSource,
2856 // Maps idents to the node ID for the
2857 // outermost pattern that binds them.
2858 bindings: &mut FxHashMap<Ident, NodeId>) {
2859 // Visit all direct subpatterns of this pattern.
2860 let outer_pat_id = pat.id;
2861 pat.walk(&mut |pat| {
2863 PatKind::Ident(bmode, ident, ref opt_pat) => {
2864 // First try to resolve the identifier as some existing
2865 // entity, then fall back to a fresh binding.
2866 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2868 .and_then(LexicalScopeBinding::item);
2869 let resolution = binding.map(NameBinding::def).and_then(|def| {
2870 let is_syntactic_ambiguity = opt_pat.is_none() &&
2871 bmode == BindingMode::ByValue(Mutability::Immutable);
2873 Def::StructCtor(_, CtorKind::Const) |
2874 Def::VariantCtor(_, CtorKind::Const) |
2875 Def::Const(..) if is_syntactic_ambiguity => {
2876 // Disambiguate in favor of a unit struct/variant
2877 // or constant pattern.
2878 self.record_use(ident, ValueNS, binding.unwrap());
2879 Some(PathResolution::new(def))
2881 Def::StructCtor(..) | Def::VariantCtor(..) |
2882 Def::Const(..) | Def::Static(..) => {
2883 // This is unambiguously a fresh binding, either syntactically
2884 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2885 // to something unusable as a pattern (e.g. constructor function),
2886 // but we still conservatively report an error, see
2887 // issues/33118#issuecomment-233962221 for one reason why.
2891 ResolutionError::BindingShadowsSomethingUnacceptable(
2892 pat_src.descr(), ident.name, binding.unwrap())
2896 Def::Fn(..) | Def::Err => {
2897 // These entities are explicitly allowed
2898 // to be shadowed by fresh bindings.
2902 span_bug!(ident.span, "unexpected definition for an \
2903 identifier in pattern: {:?}", def);
2906 }).unwrap_or_else(|| {
2907 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2910 self.record_def(pat.id, resolution);
2913 PatKind::TupleStruct(ref path, ..) => {
2914 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2917 PatKind::Path(ref qself, ref path) => {
2918 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2921 PatKind::Struct(ref path, ..) => {
2922 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2930 visit::walk_pat(self, pat);
2933 // High-level and context dependent path resolution routine.
2934 // Resolves the path and records the resolution into definition map.
2935 // If resolution fails tries several techniques to find likely
2936 // resolution candidates, suggest imports or other help, and report
2937 // errors in user friendly way.
2938 fn smart_resolve_path(&mut self,
2940 qself: Option<&QSelf>,
2944 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2947 /// A variant of `smart_resolve_path` where you also specify extra
2948 /// information about where the path came from; this extra info is
2949 /// sometimes needed for the lint that recommends rewriting
2950 /// absolute paths to `crate`, so that it knows how to frame the
2951 /// suggestion. If you are just resolving a path like `foo::bar`
2952 /// that appears...somewhere, though, then you just want
2953 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2954 /// already provides.
2955 fn smart_resolve_path_with_crate_lint(
2958 qself: Option<&QSelf>,
2961 crate_lint: CrateLint
2962 ) -> PathResolution {
2963 let segments = &path.segments.iter()
2964 .map(|seg| seg.ident)
2965 .collect::<Vec<_>>();
2966 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2969 fn smart_resolve_path_fragment(&mut self,
2971 qself: Option<&QSelf>,
2975 crate_lint: CrateLint)
2977 let ident_span = path.last().map_or(span, |ident| ident.span);
2978 let ns = source.namespace();
2979 let is_expected = &|def| source.is_expected(def);
2980 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2982 // Base error is amended with one short label and possibly some longer helps/notes.
2983 let report_errors = |this: &mut Self, def: Option<Def>| {
2984 // Make the base error.
2985 let expected = source.descr_expected();
2986 let path_str = names_to_string(path);
2987 let code = source.error_code(def.is_some());
2988 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2989 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2990 format!("not a {}", expected),
2993 let item_str = path[path.len() - 1];
2994 let item_span = path[path.len() - 1].span;
2995 let (mod_prefix, mod_str) = if path.len() == 1 {
2996 (String::new(), "this scope".to_string())
2997 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2998 (String::new(), "the crate root".to_string())
3000 let mod_path = &path[..path.len() - 1];
3001 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
3002 false, span, CrateLint::No) {
3003 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3006 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3007 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
3009 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3010 format!("not found in {}", mod_str),
3013 let code = DiagnosticId::Error(code.into());
3014 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3016 // Emit special messages for unresolved `Self` and `self`.
3017 if is_self_type(path, ns) {
3018 __diagnostic_used!(E0411);
3019 err.code(DiagnosticId::Error("E0411".into()));
3020 let available_in = if this.session.features_untracked().self_in_typedefs {
3021 "impls, traits, and type definitions"
3025 err.span_label(span, format!("`Self` is only available in {}", available_in));
3026 return (err, Vec::new());
3028 if is_self_value(path, ns) {
3029 __diagnostic_used!(E0424);
3030 err.code(DiagnosticId::Error("E0424".into()));
3031 err.span_label(span, format!("`self` value is only available in \
3032 methods with `self` parameter"));
3033 return (err, Vec::new());
3036 // Try to lookup the name in more relaxed fashion for better error reporting.
3037 let ident = *path.last().unwrap();
3038 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3039 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3040 let enum_candidates =
3041 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3042 let mut enum_candidates = enum_candidates.iter()
3043 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3044 enum_candidates.sort();
3045 for (sp, variant_path, enum_path) in enum_candidates {
3047 let msg = format!("there is an enum variant `{}`, \
3053 err.span_suggestion_with_applicability(
3055 "you can try using the variant's enum",
3057 Applicability::MachineApplicable,
3062 if path.len() == 1 && this.self_type_is_available(span) {
3063 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3064 let self_is_available = this.self_value_is_available(path[0].span, span);
3066 AssocSuggestion::Field => {
3067 err.span_suggestion_with_applicability(
3070 format!("self.{}", path_str),
3071 Applicability::MachineApplicable,
3073 if !self_is_available {
3074 err.span_label(span, format!("`self` value is only available in \
3075 methods with `self` parameter"));
3078 AssocSuggestion::MethodWithSelf if self_is_available => {
3079 err.span_suggestion_with_applicability(
3082 format!("self.{}", path_str),
3083 Applicability::MachineApplicable,
3086 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3087 err.span_suggestion_with_applicability(
3090 format!("Self::{}", path_str),
3091 Applicability::MachineApplicable,
3095 return (err, candidates);
3099 let mut levenshtein_worked = false;
3102 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3103 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3104 levenshtein_worked = true;
3107 // Try context dependent help if relaxed lookup didn't work.
3108 if let Some(def) = def {
3109 match (def, source) {
3110 (Def::Macro(..), _) => {
3111 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3112 return (err, candidates);
3114 (Def::TyAlias(..), PathSource::Trait(_)) => {
3115 err.span_label(span, "type aliases cannot be used for traits");
3116 return (err, candidates);
3118 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3119 ExprKind::Field(_, ident) => {
3120 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3122 return (err, candidates);
3124 ExprKind::MethodCall(ref segment, ..) => {
3125 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3126 path_str, segment.ident));
3127 return (err, candidates);
3131 (Def::Enum(..), PathSource::TupleStruct)
3132 | (Def::Enum(..), PathSource::Expr(..)) => {
3133 if let Some(variants) = this.collect_enum_variants(def) {
3134 err.note(&format!("did you mean to use one \
3135 of the following variants?\n{}",
3137 .map(|suggestion| path_names_to_string(suggestion))
3138 .map(|suggestion| format!("- `{}`", suggestion))
3139 .collect::<Vec<_>>()
3143 err.note("did you mean to use one of the enum's variants?");
3145 return (err, candidates);
3147 (Def::Struct(def_id), _) if ns == ValueNS => {
3148 if let Some((ctor_def, ctor_vis))
3149 = this.struct_constructors.get(&def_id).cloned() {
3150 let accessible_ctor = this.is_accessible(ctor_vis);
3151 if is_expected(ctor_def) && !accessible_ctor {
3152 err.span_label(span, format!("constructor is not visible \
3153 here due to private fields"));
3156 // HACK(estebank): find a better way to figure out that this was a
3157 // parser issue where a struct literal is being used on an expression
3158 // where a brace being opened means a block is being started. Look
3159 // ahead for the next text to see if `span` is followed by a `{`.
3160 let cm = this.session.source_map();
3163 sp = cm.next_point(sp);
3164 match cm.span_to_snippet(sp) {
3165 Ok(ref snippet) => {
3166 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3173 let followed_by_brace = match cm.span_to_snippet(sp) {
3174 Ok(ref snippet) if snippet == "{" => true,
3177 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3180 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3185 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3189 return (err, candidates);
3191 (Def::Union(..), _) |
3192 (Def::Variant(..), _) |
3193 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3194 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3196 return (err, candidates);
3198 (Def::SelfTy(..), _) if ns == ValueNS => {
3199 err.span_label(span, fallback_label);
3200 err.note("can't use `Self` as a constructor, you must use the \
3201 implemented struct");
3202 return (err, candidates);
3204 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3205 err.note("can't use a type alias as a constructor");
3206 return (err, candidates);
3213 if !levenshtein_worked {
3214 err.span_label(base_span, fallback_label);
3215 this.type_ascription_suggestion(&mut err, base_span);
3219 let report_errors = |this: &mut Self, def: Option<Def>| {
3220 let (err, candidates) = report_errors(this, def);
3221 let def_id = this.current_module.normal_ancestor_id;
3222 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3223 let better = def.is_some();
3224 this.use_injections.push(UseError { err, candidates, node_id, better });
3225 err_path_resolution()
3228 let resolution = match self.resolve_qpath_anywhere(
3234 source.defer_to_typeck(),
3235 source.global_by_default(),
3238 Some(resolution) if resolution.unresolved_segments() == 0 => {
3239 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3242 // Add a temporary hack to smooth the transition to new struct ctor
3243 // visibility rules. See #38932 for more details.
3245 if let Def::Struct(def_id) = resolution.base_def() {
3246 if let Some((ctor_def, ctor_vis))
3247 = self.struct_constructors.get(&def_id).cloned() {
3248 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3249 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3250 self.session.buffer_lint(lint, id, span,
3251 "private struct constructors are not usable through \
3252 re-exports in outer modules",
3254 res = Some(PathResolution::new(ctor_def));
3259 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3262 Some(resolution) if source.defer_to_typeck() => {
3263 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3264 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3265 // it needs to be added to the trait map.
3267 let item_name = *path.last().unwrap();
3268 let traits = self.get_traits_containing_item(item_name, ns);
3269 self.trait_map.insert(id, traits);
3273 _ => report_errors(self, None)
3276 if let PathSource::TraitItem(..) = source {} else {
3277 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3278 self.record_def(id, resolution);
3283 fn type_ascription_suggestion(&self,
3284 err: &mut DiagnosticBuilder,
3286 debug!("type_ascription_suggetion {:?}", base_span);
3287 let cm = self.session.source_map();
3288 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3289 if let Some(sp) = self.current_type_ascription.last() {
3291 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3292 sp = cm.next_point(sp);
3293 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3294 debug!("snippet {:?}", snippet);
3295 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3296 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3297 debug!("{:?} {:?}", line_sp, line_base_sp);
3299 err.span_label(base_span,
3300 "expecting a type here because of type ascription");
3301 if line_sp != line_base_sp {
3302 err.span_suggestion_short_with_applicability(
3304 "did you mean to use `;` here instead?",
3306 Applicability::MaybeIncorrect,
3310 } else if snippet.trim().len() != 0 {
3311 debug!("tried to find type ascription `:` token, couldn't find it");
3321 fn self_type_is_available(&mut self, span: Span) -> bool {
3322 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3323 TypeNS, None, span);
3324 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3327 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3328 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3329 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3330 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3333 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3334 fn resolve_qpath_anywhere(&mut self,
3336 qself: Option<&QSelf>,
3338 primary_ns: Namespace,
3340 defer_to_typeck: bool,
3341 global_by_default: bool,
3342 crate_lint: CrateLint)
3343 -> Option<PathResolution> {
3344 let mut fin_res = None;
3345 // FIXME: can't resolve paths in macro namespace yet, macros are
3346 // processed by the little special hack below.
3347 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3348 if i == 0 || ns != primary_ns {
3349 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3350 // If defer_to_typeck, then resolution > no resolution,
3351 // otherwise full resolution > partial resolution > no resolution.
3352 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3354 res => if fin_res.is_none() { fin_res = res },
3358 if primary_ns != MacroNS &&
3359 (self.macro_names.contains(&path[0].modern()) ||
3360 self.builtin_macros.get(&path[0].name).cloned()
3361 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3362 self.macro_use_prelude.get(&path[0].name).cloned()
3363 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3364 // Return some dummy definition, it's enough for error reporting.
3366 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3372 /// Handles paths that may refer to associated items.
3373 fn resolve_qpath(&mut self,
3375 qself: Option<&QSelf>,
3379 global_by_default: bool,
3380 crate_lint: CrateLint)
3381 -> Option<PathResolution> {
3383 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3384 ns={:?}, span={:?}, global_by_default={:?})",
3393 if let Some(qself) = qself {
3394 if qself.position == 0 {
3395 // This is a case like `<T>::B`, where there is no
3396 // trait to resolve. In that case, we leave the `B`
3397 // segment to be resolved by type-check.
3398 return Some(PathResolution::with_unresolved_segments(
3399 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3403 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3405 // Currently, `path` names the full item (`A::B::C`, in
3406 // our example). so we extract the prefix of that that is
3407 // the trait (the slice upto and including
3408 // `qself.position`). And then we recursively resolve that,
3409 // but with `qself` set to `None`.
3411 // However, setting `qself` to none (but not changing the
3412 // span) loses the information about where this path
3413 // *actually* appears, so for the purposes of the crate
3414 // lint we pass along information that this is the trait
3415 // name from a fully qualified path, and this also
3416 // contains the full span (the `CrateLint::QPathTrait`).
3417 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3418 let res = self.smart_resolve_path_fragment(
3421 &path[..qself.position + 1],
3423 PathSource::TraitItem(ns),
3424 CrateLint::QPathTrait {
3426 qpath_span: qself.path_span,
3430 // The remaining segments (the `C` in our example) will
3431 // have to be resolved by type-check, since that requires doing
3432 // trait resolution.
3433 return Some(PathResolution::with_unresolved_segments(
3434 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3438 let result = match self.resolve_path(
3446 PathResult::NonModule(path_res) => path_res,
3447 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3448 PathResolution::new(module.def().unwrap())
3450 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3451 // don't report an error right away, but try to fallback to a primitive type.
3452 // So, we are still able to successfully resolve something like
3454 // use std::u8; // bring module u8 in scope
3455 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3456 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3457 // // not to non-existent std::u8::max_value
3460 // Such behavior is required for backward compatibility.
3461 // The same fallback is used when `a` resolves to nothing.
3462 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3463 PathResult::Failed(..)
3464 if (ns == TypeNS || path.len() > 1) &&
3465 self.primitive_type_table.primitive_types
3466 .contains_key(&path[0].name) => {
3467 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3468 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3470 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3471 PathResolution::new(module.def().unwrap()),
3472 PathResult::Failed(span, msg, false) => {
3473 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3474 err_path_resolution()
3476 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3477 PathResult::Failed(..) => return None,
3478 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3481 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3482 path[0].name != keywords::CrateRoot.name() &&
3483 path[0].name != keywords::DollarCrate.name() {
3484 let unqualified_result = {
3485 match self.resolve_path(
3487 &[*path.last().unwrap()],
3493 PathResult::NonModule(path_res) => path_res.base_def(),
3494 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3495 module.def().unwrap(),
3496 _ => return Some(result),
3499 if result.base_def() == unqualified_result {
3500 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3501 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3510 base_module: Option<ModuleOrUniformRoot<'a>>,
3512 opt_ns: Option<Namespace>, // `None` indicates a module path
3515 crate_lint: CrateLint,
3516 ) -> PathResult<'a> {
3517 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3518 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3519 record_used, path_span, crate_lint)
3522 fn resolve_path_with_parent_scope(
3524 base_module: Option<ModuleOrUniformRoot<'a>>,
3526 opt_ns: Option<Namespace>, // `None` indicates a module path
3527 parent_scope: &ParentScope<'a>,
3530 crate_lint: CrateLint,
3531 ) -> PathResult<'a> {
3532 let mut module = base_module;
3533 let mut allow_super = true;
3534 let mut second_binding = None;
3535 self.current_module = parent_scope.module;
3538 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3539 path_span={:?}, crate_lint={:?})",
3547 for (i, &ident) in path.iter().enumerate() {
3548 debug!("resolve_path ident {} {:?}", i, ident);
3549 let is_last = i == path.len() - 1;
3550 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3551 let name = ident.name;
3553 allow_super &= ns == TypeNS &&
3554 (name == keywords::SelfValue.name() ||
3555 name == keywords::Super.name());
3558 if allow_super && name == keywords::Super.name() {
3559 let mut ctxt = ident.span.ctxt().modern();
3560 let self_module = match i {
3561 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3563 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3567 if let Some(self_module) = self_module {
3568 if let Some(parent) = self_module.parent {
3569 module = Some(ModuleOrUniformRoot::Module(
3570 self.resolve_self(&mut ctxt, parent)));
3574 let msg = "There are too many initial `super`s.".to_string();
3575 return PathResult::Failed(ident.span, msg, false);
3578 if name == keywords::SelfValue.name() {
3579 let mut ctxt = ident.span.ctxt().modern();
3580 module = Some(ModuleOrUniformRoot::Module(
3581 self.resolve_self(&mut ctxt, self.current_module)));
3584 if name == keywords::Extern.name() ||
3585 name == keywords::CrateRoot.name() &&
3586 self.session.features_untracked().extern_absolute_paths &&
3587 self.session.rust_2018() {
3588 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3591 if name == keywords::CrateRoot.name() ||
3592 name == keywords::Crate.name() ||
3593 name == keywords::DollarCrate.name() {
3594 // `::a::b`, `crate::a::b` or `$crate::a::b`
3595 module = Some(ModuleOrUniformRoot::Module(
3596 self.resolve_crate_root(ident)));
3602 // Report special messages for path segment keywords in wrong positions.
3603 if ident.is_path_segment_keyword() && i != 0 {
3604 let name_str = if name == keywords::CrateRoot.name() {
3605 "crate root".to_string()
3607 format!("`{}`", name)
3609 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3610 format!("global paths cannot start with {}", name_str)
3612 format!("{} in paths can only be used in start position", name_str)
3614 return PathResult::Failed(ident.span, msg, false);
3617 let binding = if let Some(module) = module {
3618 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3619 } else if opt_ns == Some(MacroNS) {
3620 assert!(ns == TypeNS);
3621 self.resolve_lexical_macro_path_segment(ident, ns, None, parent_scope, record_used,
3622 record_used, path_span).map(|(b, _)| b)
3624 let record_used_id =
3625 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3626 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3627 // we found a locally-imported or available item/module
3628 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3629 // we found a local variable or type param
3630 Some(LexicalScopeBinding::Def(def))
3631 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3632 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3636 _ => Err(if record_used { Determined } else { Undetermined }),
3643 second_binding = Some(binding);
3645 let def = binding.def();
3646 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3647 if let Some(next_module) = binding.module() {
3648 module = Some(ModuleOrUniformRoot::Module(next_module));
3649 } else if def == Def::ToolMod && i + 1 != path.len() {
3650 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3651 return PathResult::NonModule(PathResolution::new(def));
3652 } else if def == Def::Err {
3653 return PathResult::NonModule(err_path_resolution());
3654 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3655 self.lint_if_path_starts_with_module(
3661 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3662 def, path.len() - i - 1
3665 return PathResult::Failed(ident.span,
3666 format!("Not a module `{}`", ident),
3670 Err(Undetermined) => return PathResult::Indeterminate,
3671 Err(Determined) => {
3672 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3673 if opt_ns.is_some() && !module.is_normal() {
3674 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3675 module.def().unwrap(), path.len() - i
3679 let module_def = match module {
3680 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3683 let msg = if module_def == self.graph_root.def() {
3684 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3685 let mut candidates =
3686 self.lookup_import_candidates(name, TypeNS, is_mod);
3687 candidates.sort_by_cached_key(|c| {
3688 (c.path.segments.len(), c.path.to_string())
3690 if let Some(candidate) = candidates.get(0) {
3691 format!("Did you mean `{}`?", candidate.path)
3693 format!("Maybe a missing `extern crate {};`?", ident)
3696 format!("Use of undeclared type or module `{}`", ident)
3698 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3700 return PathResult::Failed(ident.span, msg, is_last);
3705 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3707 PathResult::Module(module.unwrap_or_else(|| {
3708 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3713 fn lint_if_path_starts_with_module(
3715 crate_lint: CrateLint,
3718 second_binding: Option<&NameBinding>,
3720 // In the 2018 edition this lint is a hard error, so nothing to do
3721 if self.session.rust_2018() {
3725 // In the 2015 edition there's no use in emitting lints unless the
3726 // crate's already enabled the feature that we're going to suggest
3727 if !self.session.features_untracked().crate_in_paths {
3731 let (diag_id, diag_span) = match crate_lint {
3732 CrateLint::No => return,
3733 CrateLint::SimplePath(id) => (id, path_span),
3734 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3735 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3738 let first_name = match path.get(0) {
3739 Some(ident) => ident.name,
3743 // We're only interested in `use` paths which should start with
3744 // `{{root}}` or `extern` currently.
3745 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3750 // If this import looks like `crate::...` it's already good
3751 Some(ident) if ident.name == keywords::Crate.name() => return,
3752 // Otherwise go below to see if it's an extern crate
3754 // If the path has length one (and it's `CrateRoot` most likely)
3755 // then we don't know whether we're gonna be importing a crate or an
3756 // item in our crate. Defer this lint to elsewhere
3760 // If the first element of our path was actually resolved to an
3761 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3762 // warning, this looks all good!
3763 if let Some(binding) = second_binding {
3764 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3765 // Careful: we still want to rewrite paths from
3766 // renamed extern crates.
3767 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3773 let diag = lint::builtin::BuiltinLintDiagnostics
3774 ::AbsPathWithModule(diag_span);
3775 self.session.buffer_lint_with_diagnostic(
3776 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3778 "absolute paths must start with `self`, `super`, \
3779 `crate`, or an external crate name in the 2018 edition",
3783 // Resolve a local definition, potentially adjusting for closures.
3784 fn adjust_local_def(&mut self,
3789 span: Span) -> Def {
3790 let ribs = &self.ribs[ns][rib_index + 1..];
3792 // An invalid forward use of a type parameter from a previous default.
3793 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3795 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3797 assert_eq!(def, Def::Err);
3803 span_bug!(span, "unexpected {:?} in bindings", def)
3805 Def::Local(node_id) => {
3808 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3809 ForwardTyParamBanRibKind => {
3810 // Nothing to do. Continue.
3812 ClosureRibKind(function_id) => {
3815 let seen = self.freevars_seen
3818 if let Some(&index) = seen.get(&node_id) {
3819 def = Def::Upvar(node_id, index, function_id);
3822 let vec = self.freevars
3825 let depth = vec.len();
3826 def = Def::Upvar(node_id, depth, function_id);
3833 seen.insert(node_id, depth);
3836 ItemRibKind | TraitOrImplItemRibKind => {
3837 // This was an attempt to access an upvar inside a
3838 // named function item. This is not allowed, so we
3841 resolve_error(self, span,
3842 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3846 ConstantItemRibKind => {
3847 // Still doesn't deal with upvars
3849 resolve_error(self, span,
3850 ResolutionError::AttemptToUseNonConstantValueInConstant);
3857 Def::TyParam(..) | Def::SelfTy(..) => {
3860 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3861 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3862 ConstantItemRibKind => {
3863 // Nothing to do. Continue.
3866 // This was an attempt to use a type parameter outside
3869 resolve_error(self, span,
3870 ResolutionError::TypeParametersFromOuterFunction(def));
3882 fn lookup_assoc_candidate<FilterFn>(&mut self,
3885 filter_fn: FilterFn)
3886 -> Option<AssocSuggestion>
3887 where FilterFn: Fn(Def) -> bool
3889 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3891 TyKind::Path(None, _) => Some(t.id),
3892 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3893 // This doesn't handle the remaining `Ty` variants as they are not
3894 // that commonly the self_type, it might be interesting to provide
3895 // support for those in future.
3900 // Fields are generally expected in the same contexts as locals.
3901 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3902 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3903 // Look for a field with the same name in the current self_type.
3904 if let Some(resolution) = self.def_map.get(&node_id) {
3905 match resolution.base_def() {
3906 Def::Struct(did) | Def::Union(did)
3907 if resolution.unresolved_segments() == 0 => {
3908 if let Some(field_names) = self.field_names.get(&did) {
3909 if field_names.iter().any(|&field_name| ident.name == field_name) {
3910 return Some(AssocSuggestion::Field);
3920 // Look for associated items in the current trait.
3921 if let Some((module, _)) = self.current_trait_ref {
3922 if let Ok(binding) = self.resolve_ident_in_module(
3923 ModuleOrUniformRoot::Module(module),
3929 let def = binding.def();
3931 return Some(if self.has_self.contains(&def.def_id()) {
3932 AssocSuggestion::MethodWithSelf
3934 AssocSuggestion::AssocItem
3943 fn lookup_typo_candidate<FilterFn>(&mut self,
3946 filter_fn: FilterFn,
3949 where FilterFn: Fn(Def) -> bool
3951 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3952 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3953 if let Some(binding) = resolution.borrow().binding {
3954 if filter_fn(binding.def()) {
3955 names.push(ident.name);
3961 let mut names = Vec::new();
3962 if path.len() == 1 {
3963 // Search in lexical scope.
3964 // Walk backwards up the ribs in scope and collect candidates.
3965 for rib in self.ribs[ns].iter().rev() {
3966 // Locals and type parameters
3967 for (ident, def) in &rib.bindings {
3968 if filter_fn(*def) {
3969 names.push(ident.name);
3973 if let ModuleRibKind(module) = rib.kind {
3974 // Items from this module
3975 add_module_candidates(module, &mut names);
3977 if let ModuleKind::Block(..) = module.kind {
3978 // We can see through blocks
3980 // Items from the prelude
3981 if !module.no_implicit_prelude {
3982 names.extend(self.extern_prelude.iter().cloned());
3983 if let Some(prelude) = self.prelude {
3984 add_module_candidates(prelude, &mut names);
3991 // Add primitive types to the mix
3992 if filter_fn(Def::PrimTy(Bool)) {
3994 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3998 // Search in module.
3999 let mod_path = &path[..path.len() - 1];
4000 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
4001 false, span, CrateLint::No) {
4002 if let ModuleOrUniformRoot::Module(module) = module {
4003 add_module_candidates(module, &mut names);
4008 let name = path[path.len() - 1].name;
4009 // Make sure error reporting is deterministic.
4010 names.sort_by_cached_key(|name| name.as_str());
4011 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4012 Some(found) if found != name => Some(found),
4017 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4018 where F: FnOnce(&mut Resolver)
4020 if let Some(label) = label {
4021 self.unused_labels.insert(id, label.ident.span);
4022 let def = Def::Label(id);
4023 self.with_label_rib(|this| {
4024 let ident = label.ident.modern_and_legacy();
4025 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4033 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4034 self.with_resolved_label(label, id, |this| this.visit_block(block));
4037 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4038 // First, record candidate traits for this expression if it could
4039 // result in the invocation of a method call.
4041 self.record_candidate_traits_for_expr_if_necessary(expr);
4043 // Next, resolve the node.
4045 ExprKind::Path(ref qself, ref path) => {
4046 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4047 visit::walk_expr(self, expr);
4050 ExprKind::Struct(ref path, ..) => {
4051 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4052 visit::walk_expr(self, expr);
4055 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4056 let def = self.search_label(label.ident, |rib, ident| {
4057 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4061 // Search again for close matches...
4062 // Picks the first label that is "close enough", which is not necessarily
4063 // the closest match
4064 let close_match = self.search_label(label.ident, |rib, ident| {
4065 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4066 find_best_match_for_name(names, &*ident.as_str(), None)
4068 self.record_def(expr.id, err_path_resolution());
4071 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4074 Some(Def::Label(id)) => {
4075 // Since this def is a label, it is never read.
4076 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4077 self.unused_labels.remove(&id);
4080 span_bug!(expr.span, "label wasn't mapped to a label def!");
4084 // visit `break` argument if any
4085 visit::walk_expr(self, expr);
4088 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4089 self.visit_expr(subexpression);
4091 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4092 let mut bindings_list = FxHashMap();
4094 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4096 // This has to happen *after* we determine which pat_idents are variants
4097 self.check_consistent_bindings(pats);
4098 self.visit_block(if_block);
4099 self.ribs[ValueNS].pop();
4101 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4104 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4106 ExprKind::While(ref subexpression, ref block, label) => {
4107 self.with_resolved_label(label, expr.id, |this| {
4108 this.visit_expr(subexpression);
4109 this.visit_block(block);
4113 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4114 self.with_resolved_label(label, expr.id, |this| {
4115 this.visit_expr(subexpression);
4116 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4117 let mut bindings_list = FxHashMap();
4119 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4121 // This has to happen *after* we determine which pat_idents are variants
4122 this.check_consistent_bindings(pats);
4123 this.visit_block(block);
4124 this.ribs[ValueNS].pop();
4128 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4129 self.visit_expr(subexpression);
4130 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4131 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4133 self.resolve_labeled_block(label, expr.id, block);
4135 self.ribs[ValueNS].pop();
4138 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4140 // Equivalent to `visit::walk_expr` + passing some context to children.
4141 ExprKind::Field(ref subexpression, _) => {
4142 self.resolve_expr(subexpression, Some(expr));
4144 ExprKind::MethodCall(ref segment, ref arguments) => {
4145 let mut arguments = arguments.iter();
4146 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4147 for argument in arguments {
4148 self.resolve_expr(argument, None);
4150 self.visit_path_segment(expr.span, segment);
4153 ExprKind::Call(ref callee, ref arguments) => {
4154 self.resolve_expr(callee, Some(expr));
4155 for argument in arguments {
4156 self.resolve_expr(argument, None);
4159 ExprKind::Type(ref type_expr, _) => {
4160 self.current_type_ascription.push(type_expr.span);
4161 visit::walk_expr(self, expr);
4162 self.current_type_ascription.pop();
4164 // Resolve the body of async exprs inside the async closure to which they desugar
4165 ExprKind::Async(_, async_closure_id, ref block) => {
4166 let rib_kind = ClosureRibKind(async_closure_id);
4167 self.ribs[ValueNS].push(Rib::new(rib_kind));
4168 self.label_ribs.push(Rib::new(rib_kind));
4169 self.visit_block(&block);
4170 self.label_ribs.pop();
4171 self.ribs[ValueNS].pop();
4173 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4174 // resolve the arguments within the proper scopes so that usages of them inside the
4175 // closure are detected as upvars rather than normal closure arg usages.
4177 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4178 ref fn_decl, ref body, _span,
4180 let rib_kind = ClosureRibKind(expr.id);
4181 self.ribs[ValueNS].push(Rib::new(rib_kind));
4182 self.label_ribs.push(Rib::new(rib_kind));
4183 // Resolve arguments:
4184 let mut bindings_list = FxHashMap();
4185 for argument in &fn_decl.inputs {
4186 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4187 self.visit_ty(&argument.ty);
4189 // No need to resolve return type-- the outer closure return type is
4190 // FunctionRetTy::Default
4192 // Now resolve the inner closure
4194 let rib_kind = ClosureRibKind(inner_closure_id);
4195 self.ribs[ValueNS].push(Rib::new(rib_kind));
4196 self.label_ribs.push(Rib::new(rib_kind));
4197 // No need to resolve arguments: the inner closure has none.
4198 // Resolve the return type:
4199 visit::walk_fn_ret_ty(self, &fn_decl.output);
4201 self.visit_expr(body);
4202 self.label_ribs.pop();
4203 self.ribs[ValueNS].pop();
4205 self.label_ribs.pop();
4206 self.ribs[ValueNS].pop();
4209 visit::walk_expr(self, expr);
4214 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4216 ExprKind::Field(_, ident) => {
4217 // FIXME(#6890): Even though you can't treat a method like a
4218 // field, we need to add any trait methods we find that match
4219 // the field name so that we can do some nice error reporting
4220 // later on in typeck.
4221 let traits = self.get_traits_containing_item(ident, ValueNS);
4222 self.trait_map.insert(expr.id, traits);
4224 ExprKind::MethodCall(ref segment, ..) => {
4225 debug!("(recording candidate traits for expr) recording traits for {}",
4227 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4228 self.trait_map.insert(expr.id, traits);
4236 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4237 -> Vec<TraitCandidate> {
4238 debug!("(getting traits containing item) looking for '{}'", ident.name);
4240 let mut found_traits = Vec::new();
4241 // Look for the current trait.
4242 if let Some((module, _)) = self.current_trait_ref {
4243 if self.resolve_ident_in_module(
4244 ModuleOrUniformRoot::Module(module),
4250 let def_id = module.def_id().unwrap();
4251 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4255 ident.span = ident.span.modern();
4256 let mut search_module = self.current_module;
4258 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4259 search_module = unwrap_or!(
4260 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4264 if let Some(prelude) = self.prelude {
4265 if !search_module.no_implicit_prelude {
4266 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4273 fn get_traits_in_module_containing_item(&mut self,
4277 found_traits: &mut Vec<TraitCandidate>) {
4278 assert!(ns == TypeNS || ns == ValueNS);
4279 let mut traits = module.traits.borrow_mut();
4280 if traits.is_none() {
4281 let mut collected_traits = Vec::new();
4282 module.for_each_child(|name, ns, binding| {
4283 if ns != TypeNS { return }
4284 if let Def::Trait(_) = binding.def() {
4285 collected_traits.push((name, binding));
4288 *traits = Some(collected_traits.into_boxed_slice());
4291 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4292 let module = binding.module().unwrap();
4293 let mut ident = ident;
4294 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4297 if self.resolve_ident_in_module_unadjusted(
4298 ModuleOrUniformRoot::Module(module),
4305 let import_id = match binding.kind {
4306 NameBindingKind::Import { directive, .. } => {
4307 self.maybe_unused_trait_imports.insert(directive.id);
4308 self.add_to_glob_map(directive.id, trait_name);
4313 let trait_def_id = module.def_id().unwrap();
4314 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4319 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4321 namespace: Namespace,
4322 start_module: &'a ModuleData<'a>,
4324 filter_fn: FilterFn)
4325 -> Vec<ImportSuggestion>
4326 where FilterFn: Fn(Def) -> bool
4328 let mut candidates = Vec::new();
4329 let mut worklist = Vec::new();
4330 let mut seen_modules = FxHashSet();
4331 let not_local_module = crate_name != keywords::Crate.ident();
4332 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4334 while let Some((in_module,
4336 in_module_is_extern)) = worklist.pop() {
4337 self.populate_module_if_necessary(in_module);
4339 // We have to visit module children in deterministic order to avoid
4340 // instabilities in reported imports (#43552).
4341 in_module.for_each_child_stable(|ident, ns, name_binding| {
4342 // avoid imports entirely
4343 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4344 // avoid non-importable candidates as well
4345 if !name_binding.is_importable() { return; }
4347 // collect results based on the filter function
4348 if ident.name == lookup_name && ns == namespace {
4349 if filter_fn(name_binding.def()) {
4351 let mut segms = path_segments.clone();
4352 if self.session.rust_2018() {
4353 // crate-local absolute paths start with `crate::` in edition 2018
4354 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4356 0, ast::PathSegment::from_ident(crate_name)
4360 segms.push(ast::PathSegment::from_ident(ident));
4362 span: name_binding.span,
4365 // the entity is accessible in the following cases:
4366 // 1. if it's defined in the same crate, it's always
4367 // accessible (since private entities can be made public)
4368 // 2. if it's defined in another crate, it's accessible
4369 // only if both the module is public and the entity is
4370 // declared as public (due to pruning, we don't explore
4371 // outside crate private modules => no need to check this)
4372 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4373 candidates.push(ImportSuggestion { path: path });
4378 // collect submodules to explore
4379 if let Some(module) = name_binding.module() {
4381 let mut path_segments = path_segments.clone();
4382 path_segments.push(ast::PathSegment::from_ident(ident));
4384 let is_extern_crate_that_also_appears_in_prelude =
4385 name_binding.is_extern_crate() &&
4386 self.session.rust_2018();
4388 let is_visible_to_user =
4389 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4391 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4392 // add the module to the lookup
4393 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4394 if seen_modules.insert(module.def_id().unwrap()) {
4395 worklist.push((module, path_segments, is_extern));
4405 /// When name resolution fails, this method can be used to look up candidate
4406 /// entities with the expected name. It allows filtering them using the
4407 /// supplied predicate (which should be used to only accept the types of
4408 /// definitions expected e.g. traits). The lookup spans across all crates.
4410 /// NOTE: The method does not look into imports, but this is not a problem,
4411 /// since we report the definitions (thus, the de-aliased imports).
4412 fn lookup_import_candidates<FilterFn>(&mut self,
4414 namespace: Namespace,
4415 filter_fn: FilterFn)
4416 -> Vec<ImportSuggestion>
4417 where FilterFn: Fn(Def) -> bool
4419 let mut suggestions = vec![];
4422 self.lookup_import_candidates_from_module(
4423 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4427 if self.session.features_untracked().extern_prelude {
4428 let extern_prelude_names = self.extern_prelude.clone();
4429 for &name in extern_prelude_names.iter() {
4430 let ident = Ident::with_empty_ctxt(name);
4431 match self.crate_loader.maybe_process_path_extern(name, ident.span) {
4433 let crate_root = self.get_module(DefId {
4435 index: CRATE_DEF_INDEX,
4437 self.populate_module_if_necessary(&crate_root);
4440 self.lookup_import_candidates_from_module(
4441 lookup_name, namespace, crate_root, ident, &filter_fn
4453 fn find_module(&mut self,
4455 -> Option<(Module<'a>, ImportSuggestion)>
4457 let mut result = None;
4458 let mut worklist = Vec::new();
4459 let mut seen_modules = FxHashSet();
4460 worklist.push((self.graph_root, Vec::new()));
4462 while let Some((in_module, path_segments)) = worklist.pop() {
4463 // abort if the module is already found
4464 if result.is_some() { break; }
4466 self.populate_module_if_necessary(in_module);
4468 in_module.for_each_child_stable(|ident, _, name_binding| {
4469 // abort if the module is already found or if name_binding is private external
4470 if result.is_some() || !name_binding.vis.is_visible_locally() {
4473 if let Some(module) = name_binding.module() {
4475 let mut path_segments = path_segments.clone();
4476 path_segments.push(ast::PathSegment::from_ident(ident));
4477 if module.def() == Some(module_def) {
4479 span: name_binding.span,
4480 segments: path_segments,
4482 result = Some((module, ImportSuggestion { path: path }));
4484 // add the module to the lookup
4485 if seen_modules.insert(module.def_id().unwrap()) {
4486 worklist.push((module, path_segments));
4496 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4497 if let Def::Enum(..) = enum_def {} else {
4498 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4501 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4502 self.populate_module_if_necessary(enum_module);
4504 let mut variants = Vec::new();
4505 enum_module.for_each_child_stable(|ident, _, name_binding| {
4506 if let Def::Variant(..) = name_binding.def() {
4507 let mut segms = enum_import_suggestion.path.segments.clone();
4508 segms.push(ast::PathSegment::from_ident(ident));
4509 variants.push(Path {
4510 span: name_binding.span,
4519 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4520 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4521 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4522 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4526 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4528 ast::VisibilityKind::Public => ty::Visibility::Public,
4529 ast::VisibilityKind::Crate(..) => {
4530 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4532 ast::VisibilityKind::Inherited => {
4533 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4535 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4536 // Visibilities are resolved as global by default, add starting root segment.
4537 let segments = path.make_root().iter().chain(path.segments.iter())
4538 .map(|seg| seg.ident)
4539 .collect::<Vec<_>>();
4540 let def = self.smart_resolve_path_fragment(
4545 PathSource::Visibility,
4546 CrateLint::SimplePath(id),
4548 if def == Def::Err {
4549 ty::Visibility::Public
4551 let vis = ty::Visibility::Restricted(def.def_id());
4552 if self.is_accessible(vis) {
4555 self.session.span_err(path.span, "visibilities can only be restricted \
4556 to ancestor modules");
4557 ty::Visibility::Public
4564 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4565 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4568 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4569 vis.is_accessible_from(module.normal_ancestor_id, self)
4572 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4573 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4575 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4577 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4578 let note = if b1.expansion != Mark::root() {
4579 Some(if let Def::Macro(..) = b1.def() {
4580 format!("macro-expanded {} do not shadow",
4581 if b1.is_import() { "macro imports" } else { "macros" })
4583 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4584 if b1.is_import() { "imports" } else { "items" })
4586 } else if b1.is_glob_import() {
4587 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4592 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4593 err.span_label(ident.span, "ambiguous name");
4594 err.span_note(b1.span, &msg1);
4596 Def::Macro(..) if b2.span.is_dummy() =>
4597 err.note(&format!("`{}` is also a builtin macro", ident)),
4598 _ => err.span_note(b2.span, &msg2),
4600 if let Some(note) = note {
4606 fn report_errors(&mut self, krate: &Crate) {
4607 self.report_with_use_injections(krate);
4608 self.report_proc_macro_import(krate);
4609 let mut reported_spans = FxHashSet();
4611 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4612 let msg = "macro-expanded `macro_export` macros from the current crate \
4613 cannot be referred to by absolute paths";
4614 self.session.buffer_lint_with_diagnostic(
4615 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4616 CRATE_NODE_ID, span_use, msg,
4617 lint::builtin::BuiltinLintDiagnostics::
4618 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4622 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4623 if reported_spans.insert(ident.span) {
4624 self.report_ambiguity_error(ident, b1, b2);
4628 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4629 if !reported_spans.insert(span) { continue }
4630 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4634 fn report_with_use_injections(&mut self, krate: &Crate) {
4635 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4636 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4637 if !candidates.is_empty() {
4638 show_candidates(&mut err, span, &candidates, better, found_use);
4644 fn report_conflict<'b>(&mut self,
4648 new_binding: &NameBinding<'b>,
4649 old_binding: &NameBinding<'b>) {
4650 // Error on the second of two conflicting names
4651 if old_binding.span.lo() > new_binding.span.lo() {
4652 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4655 let container = match parent.kind {
4656 ModuleKind::Def(Def::Mod(_), _) => "module",
4657 ModuleKind::Def(Def::Trait(_), _) => "trait",
4658 ModuleKind::Block(..) => "block",
4662 let old_noun = match old_binding.is_import() {
4664 false => "definition",
4667 let new_participle = match new_binding.is_import() {
4672 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4674 if let Some(s) = self.name_already_seen.get(&name) {
4680 let old_kind = match (ns, old_binding.module()) {
4681 (ValueNS, _) => "value",
4682 (MacroNS, _) => "macro",
4683 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4684 (TypeNS, Some(module)) if module.is_normal() => "module",
4685 (TypeNS, Some(module)) if module.is_trait() => "trait",
4686 (TypeNS, _) => "type",
4689 let msg = format!("the name `{}` is defined multiple times", name);
4691 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4692 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4693 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4694 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4695 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4697 _ => match (old_binding.is_import(), new_binding.is_import()) {
4698 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4699 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4700 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4704 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4709 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4710 if !old_binding.span.is_dummy() {
4711 err.span_label(self.session.source_map().def_span(old_binding.span),
4712 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4715 // See https://github.com/rust-lang/rust/issues/32354
4716 if old_binding.is_import() || new_binding.is_import() {
4717 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4723 let cm = self.session.source_map();
4724 let rename_msg = "You can use `as` to change the binding name of the import";
4726 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4727 binding.is_renamed_extern_crate()) {
4728 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4729 format!("Other{}", name)
4731 format!("other_{}", name)
4734 err.span_suggestion_with_applicability(
4737 if snippet.ends_with(';') {
4738 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4740 format!("{} as {}", snippet, suggested_name)
4742 Applicability::MachineApplicable,
4745 err.span_label(binding.span, rename_msg);
4750 self.name_already_seen.insert(name, span);
4754 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4755 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4758 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4759 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4762 fn names_to_string(idents: &[Ident]) -> String {
4763 let mut result = String::new();
4764 for (i, ident) in idents.iter()
4765 .filter(|ident| ident.name != keywords::CrateRoot.name())
4768 result.push_str("::");
4770 result.push_str(&ident.as_str());
4775 fn path_names_to_string(path: &Path) -> String {
4776 names_to_string(&path.segments.iter()
4777 .map(|seg| seg.ident)
4778 .collect::<Vec<_>>())
4781 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4782 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4783 let variant_path = &suggestion.path;
4784 let variant_path_string = path_names_to_string(variant_path);
4786 let path_len = suggestion.path.segments.len();
4787 let enum_path = ast::Path {
4788 span: suggestion.path.span,
4789 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4791 let enum_path_string = path_names_to_string(&enum_path);
4793 (suggestion.path.span, variant_path_string, enum_path_string)
4797 /// When an entity with a given name is not available in scope, we search for
4798 /// entities with that name in all crates. This method allows outputting the
4799 /// results of this search in a programmer-friendly way
4800 fn show_candidates(err: &mut DiagnosticBuilder,
4801 // This is `None` if all placement locations are inside expansions
4803 candidates: &[ImportSuggestion],
4807 // we want consistent results across executions, but candidates are produced
4808 // by iterating through a hash map, so make sure they are ordered:
4809 let mut path_strings: Vec<_> =
4810 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4811 path_strings.sort();
4813 let better = if better { "better " } else { "" };
4814 let msg_diff = match path_strings.len() {
4815 1 => " is found in another module, you can import it",
4816 _ => "s are found in other modules, you can import them",
4818 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4820 if let Some(span) = span {
4821 for candidate in &mut path_strings {
4822 // produce an additional newline to separate the new use statement
4823 // from the directly following item.
4824 let additional_newline = if found_use {
4829 *candidate = format!("use {};\n{}", candidate, additional_newline);
4832 err.span_suggestions_with_applicability(
4836 Applicability::Unspecified,
4841 for candidate in path_strings {
4843 msg.push_str(&candidate);
4848 /// A somewhat inefficient routine to obtain the name of a module.
4849 fn module_to_string(module: Module) -> Option<String> {
4850 let mut names = Vec::new();
4852 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4853 if let ModuleKind::Def(_, name) = module.kind {
4854 if let Some(parent) = module.parent {
4855 names.push(Ident::with_empty_ctxt(name));
4856 collect_mod(names, parent);
4859 // danger, shouldn't be ident?
4860 names.push(Ident::from_str("<opaque>"));
4861 collect_mod(names, module.parent.unwrap());
4864 collect_mod(&mut names, module);
4866 if names.is_empty() {
4869 Some(names_to_string(&names.into_iter()
4871 .collect::<Vec<_>>()))
4874 fn err_path_resolution() -> PathResolution {
4875 PathResolution::new(Def::Err)
4878 #[derive(PartialEq,Copy, Clone)]
4879 pub enum MakeGlobMap {
4884 #[derive(Copy, Clone, Debug)]
4886 /// Do not issue the lint
4889 /// This lint applies to some random path like `impl ::foo::Bar`
4890 /// or whatever. In this case, we can take the span of that path.
4893 /// This lint comes from a `use` statement. In this case, what we
4894 /// care about really is the *root* `use` statement; e.g., if we
4895 /// have nested things like `use a::{b, c}`, we care about the
4897 UsePath { root_id: NodeId, root_span: Span },
4899 /// This is the "trait item" from a fully qualified path. For example,
4900 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4901 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4902 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4906 fn node_id(&self) -> Option<NodeId> {
4908 CrateLint::No => None,
4909 CrateLint::SimplePath(id) |
4910 CrateLint::UsePath { root_id: id, .. } |
4911 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4916 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }