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(..) => true,
564 PathSource::Pat => match def {
565 Def::StructCtor(_, CtorKind::Const) |
566 Def::VariantCtor(_, CtorKind::Const) |
567 Def::Const(..) | Def::AssociatedConst(..) => true,
570 PathSource::TupleStruct => match def {
571 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
574 PathSource::Struct => match def {
575 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
576 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
579 PathSource::TraitItem(ns) => match def {
580 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
581 Def::AssociatedTy(..) if ns == TypeNS => true,
584 PathSource::ImportPrefix => match def {
585 Def::Mod(..) | Def::Enum(..) => true,
588 PathSource::Visibility => match def {
589 Def::Mod(..) => true,
595 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
596 __diagnostic_used!(E0404);
597 __diagnostic_used!(E0405);
598 __diagnostic_used!(E0412);
599 __diagnostic_used!(E0422);
600 __diagnostic_used!(E0423);
601 __diagnostic_used!(E0425);
602 __diagnostic_used!(E0531);
603 __diagnostic_used!(E0532);
604 __diagnostic_used!(E0573);
605 __diagnostic_used!(E0574);
606 __diagnostic_used!(E0575);
607 __diagnostic_used!(E0576);
608 __diagnostic_used!(E0577);
609 __diagnostic_used!(E0578);
610 match (self, has_unexpected_resolution) {
611 (PathSource::Trait(_), true) => "E0404",
612 (PathSource::Trait(_), false) => "E0405",
613 (PathSource::Type, true) => "E0573",
614 (PathSource::Type, false) => "E0412",
615 (PathSource::Struct, true) => "E0574",
616 (PathSource::Struct, false) => "E0422",
617 (PathSource::Expr(..), true) => "E0423",
618 (PathSource::Expr(..), false) => "E0425",
619 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
620 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
621 (PathSource::TraitItem(..), true) => "E0575",
622 (PathSource::TraitItem(..), false) => "E0576",
623 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
624 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
629 struct UsePlacementFinder {
630 target_module: NodeId,
635 impl UsePlacementFinder {
636 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
637 let mut finder = UsePlacementFinder {
642 visit::walk_crate(&mut finder, krate);
643 (finder.span, finder.found_use)
647 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
650 module: &'tcx ast::Mod,
652 _: &[ast::Attribute],
655 if self.span.is_some() {
658 if node_id != self.target_module {
659 visit::walk_mod(self, module);
662 // find a use statement
663 for item in &module.items {
665 ItemKind::Use(..) => {
666 // don't suggest placing a use before the prelude
667 // import or other generated ones
668 if item.span.ctxt().outer().expn_info().is_none() {
669 self.span = Some(item.span.shrink_to_lo());
670 self.found_use = true;
674 // don't place use before extern crate
675 ItemKind::ExternCrate(_) => {}
676 // but place them before the first other item
677 _ => if self.span.map_or(true, |span| item.span < span ) {
678 if item.span.ctxt().outer().expn_info().is_none() {
679 // don't insert between attributes and an item
680 if item.attrs.is_empty() {
681 self.span = Some(item.span.shrink_to_lo());
683 // find the first attribute on the item
684 for attr in &item.attrs {
685 if self.span.map_or(true, |span| attr.span < span) {
686 self.span = Some(attr.span.shrink_to_lo());
697 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
698 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
699 fn visit_item(&mut self, item: &'tcx Item) {
700 self.resolve_item(item);
702 fn visit_arm(&mut self, arm: &'tcx Arm) {
703 self.resolve_arm(arm);
705 fn visit_block(&mut self, block: &'tcx Block) {
706 self.resolve_block(block);
708 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
709 self.with_constant_rib(|this| {
710 visit::walk_anon_const(this, constant);
713 fn visit_expr(&mut self, expr: &'tcx Expr) {
714 self.resolve_expr(expr, None);
716 fn visit_local(&mut self, local: &'tcx Local) {
717 self.resolve_local(local);
719 fn visit_ty(&mut self, ty: &'tcx Ty) {
721 TyKind::Path(ref qself, ref path) => {
722 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
724 TyKind::ImplicitSelf => {
725 let self_ty = keywords::SelfType.ident();
726 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
727 .map_or(Def::Err, |d| d.def());
728 self.record_def(ty.id, PathResolution::new(def));
732 visit::walk_ty(self, ty);
734 fn visit_poly_trait_ref(&mut self,
735 tref: &'tcx ast::PolyTraitRef,
736 m: &'tcx ast::TraitBoundModifier) {
737 self.smart_resolve_path(tref.trait_ref.ref_id, None,
738 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
739 visit::walk_poly_trait_ref(self, tref, m);
741 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
742 let type_parameters = match foreign_item.node {
743 ForeignItemKind::Fn(_, ref generics) => {
744 HasTypeParameters(generics, ItemRibKind)
746 ForeignItemKind::Static(..) => NoTypeParameters,
747 ForeignItemKind::Ty => NoTypeParameters,
748 ForeignItemKind::Macro(..) => NoTypeParameters,
750 self.with_type_parameter_rib(type_parameters, |this| {
751 visit::walk_foreign_item(this, foreign_item);
754 fn visit_fn(&mut self,
755 function_kind: FnKind<'tcx>,
756 declaration: &'tcx FnDecl,
760 let (rib_kind, asyncness) = match function_kind {
761 FnKind::ItemFn(_, ref header, ..) =>
762 (ItemRibKind, header.asyncness),
763 FnKind::Method(_, ref sig, _, _) =>
764 (TraitOrImplItemRibKind, sig.header.asyncness),
765 FnKind::Closure(_) =>
766 // Async closures aren't resolved through `visit_fn`-- they're
767 // processed separately
768 (ClosureRibKind(node_id), IsAsync::NotAsync),
771 // Create a value rib for the function.
772 self.ribs[ValueNS].push(Rib::new(rib_kind));
774 // Create a label rib for the function.
775 self.label_ribs.push(Rib::new(rib_kind));
777 // Add each argument to the rib.
778 let mut bindings_list = FxHashMap();
779 for argument in &declaration.inputs {
780 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
782 self.visit_ty(&argument.ty);
784 debug!("(resolving function) recorded argument");
786 visit::walk_fn_ret_ty(self, &declaration.output);
788 // Resolve the function body, potentially inside the body of an async closure
789 if let IsAsync::Async { closure_id, .. } = asyncness {
790 let rib_kind = ClosureRibKind(closure_id);
791 self.ribs[ValueNS].push(Rib::new(rib_kind));
792 self.label_ribs.push(Rib::new(rib_kind));
795 match function_kind {
796 FnKind::ItemFn(.., body) |
797 FnKind::Method(.., body) => {
798 self.visit_block(body);
800 FnKind::Closure(body) => {
801 self.visit_expr(body);
805 // Leave the body of the async closure
806 if asyncness.is_async() {
807 self.label_ribs.pop();
808 self.ribs[ValueNS].pop();
811 debug!("(resolving function) leaving function");
813 self.label_ribs.pop();
814 self.ribs[ValueNS].pop();
816 fn visit_generics(&mut self, generics: &'tcx Generics) {
817 // For type parameter defaults, we have to ban access
818 // to following type parameters, as the Substs can only
819 // provide previous type parameters as they're built. We
820 // put all the parameters on the ban list and then remove
821 // them one by one as they are processed and become available.
822 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
823 let mut found_default = false;
824 default_ban_rib.bindings.extend(generics.params.iter()
825 .filter_map(|param| match param.kind {
826 GenericParamKind::Lifetime { .. } => None,
827 GenericParamKind::Type { ref default, .. } => {
828 found_default |= default.is_some();
830 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
837 for param in &generics.params {
839 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
840 GenericParamKind::Type { ref default, .. } => {
841 for bound in ¶m.bounds {
842 self.visit_param_bound(bound);
845 if let Some(ref ty) = default {
846 self.ribs[TypeNS].push(default_ban_rib);
848 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
851 // Allow all following defaults to refer to this type parameter.
852 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
856 for p in &generics.where_clause.predicates {
857 self.visit_where_predicate(p);
862 #[derive(Copy, Clone)]
863 enum TypeParameters<'a, 'b> {
865 HasTypeParameters(// Type parameters.
868 // The kind of the rib used for type parameters.
872 /// The rib kind controls the translation of local
873 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
874 #[derive(Copy, Clone, Debug)]
876 /// No translation needs to be applied.
879 /// We passed through a closure scope at the given node ID.
880 /// Translate upvars as appropriate.
881 ClosureRibKind(NodeId /* func id */),
883 /// We passed through an impl or trait and are now in one of its
884 /// methods or associated types. Allow references to ty params that impl or trait
885 /// binds. Disallow any other upvars (including other ty params that are
887 TraitOrImplItemRibKind,
889 /// We passed through an item scope. Disallow upvars.
892 /// We're in a constant item. Can't refer to dynamic stuff.
895 /// We passed through a module.
896 ModuleRibKind(Module<'a>),
898 /// We passed through a `macro_rules!` statement
899 MacroDefinition(DefId),
901 /// All bindings in this rib are type parameters that can't be used
902 /// from the default of a type parameter because they're not declared
903 /// before said type parameter. Also see the `visit_generics` override.
904 ForwardTyParamBanRibKind,
909 /// A rib represents a scope names can live in. Note that these appear in many places, not just
910 /// around braces. At any place where the list of accessible names (of the given namespace)
911 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
912 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
915 /// Different [rib kinds](enum.RibKind) are transparent for different names.
917 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
918 /// resolving, the name is looked up from inside out.
921 bindings: FxHashMap<Ident, Def>,
926 fn new(kind: RibKind<'a>) -> Rib<'a> {
928 bindings: FxHashMap(),
934 /// An intermediate resolution result.
936 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
937 /// items are visible in their whole block, while defs only from the place they are defined
939 enum LexicalScopeBinding<'a> {
940 Item(&'a NameBinding<'a>),
944 impl<'a> LexicalScopeBinding<'a> {
945 fn item(self) -> Option<&'a NameBinding<'a>> {
947 LexicalScopeBinding::Item(binding) => Some(binding),
952 fn def(self) -> Def {
954 LexicalScopeBinding::Item(binding) => binding.def(),
955 LexicalScopeBinding::Def(def) => def,
960 #[derive(Copy, Clone, Debug)]
961 pub enum ModuleOrUniformRoot<'a> {
965 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
966 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
967 /// but *not* `extern`), in the Rust 2018 edition.
971 #[derive(Clone, Debug)]
972 enum PathResult<'a> {
973 Module(ModuleOrUniformRoot<'a>),
974 NonModule(PathResolution),
976 Failed(Span, String, bool /* is the error from the last segment? */),
980 /// An anonymous module, eg. just a block.
985 /// { // This is an anonymous module
986 /// f(); // This resolves to (2) as we are inside the block.
989 /// f(); // Resolves to (1)
993 /// Any module with a name.
997 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
998 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1003 /// One node in the tree of modules.
1004 pub struct ModuleData<'a> {
1005 parent: Option<Module<'a>>,
1008 // The def id of the closest normal module (`mod`) ancestor (including this module).
1009 normal_ancestor_id: DefId,
1011 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1012 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>, Option<Def>)>>,
1013 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1014 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1016 // Macro invocations that can expand into items in this module.
1017 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1019 no_implicit_prelude: bool,
1021 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1022 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1024 // Used to memoize the traits in this module for faster searches through all traits in scope.
1025 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1027 // Whether this module is populated. If not populated, any attempt to
1028 // access the children must be preceded with a
1029 // `populate_module_if_necessary` call.
1030 populated: Cell<bool>,
1032 /// Span of the module itself. Used for error reporting.
1038 type Module<'a> = &'a ModuleData<'a>;
1040 impl<'a> ModuleData<'a> {
1041 fn new(parent: Option<Module<'a>>,
1043 normal_ancestor_id: DefId,
1045 span: Span) -> Self {
1050 resolutions: RefCell::new(FxHashMap()),
1051 legacy_macro_resolutions: RefCell::new(Vec::new()),
1052 macro_resolutions: RefCell::new(Vec::new()),
1053 builtin_attrs: RefCell::new(Vec::new()),
1054 unresolved_invocations: RefCell::new(FxHashSet()),
1055 no_implicit_prelude: false,
1056 glob_importers: RefCell::new(Vec::new()),
1057 globs: RefCell::new(Vec::new()),
1058 traits: RefCell::new(None),
1059 populated: Cell::new(normal_ancestor_id.is_local()),
1065 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1066 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1067 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1071 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1072 let resolutions = self.resolutions.borrow();
1073 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1074 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1075 for &(&(ident, ns), &resolution) in resolutions.iter() {
1076 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1080 fn def(&self) -> Option<Def> {
1082 ModuleKind::Def(def, _) => Some(def),
1087 fn def_id(&self) -> Option<DefId> {
1088 self.def().as_ref().map(Def::def_id)
1091 // `self` resolves to the first module ancestor that `is_normal`.
1092 fn is_normal(&self) -> bool {
1094 ModuleKind::Def(Def::Mod(_), _) => true,
1099 fn is_trait(&self) -> bool {
1101 ModuleKind::Def(Def::Trait(_), _) => true,
1106 fn is_local(&self) -> bool {
1107 self.normal_ancestor_id.is_local()
1110 fn nearest_item_scope(&'a self) -> Module<'a> {
1111 if self.is_trait() { self.parent.unwrap() } else { self }
1115 impl<'a> fmt::Debug for ModuleData<'a> {
1116 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1117 write!(f, "{:?}", self.def())
1121 /// Records a possibly-private value, type, or module definition.
1122 #[derive(Clone, Debug)]
1123 pub struct NameBinding<'a> {
1124 kind: NameBindingKind<'a>,
1127 vis: ty::Visibility,
1130 pub trait ToNameBinding<'a> {
1131 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1134 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1135 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1140 #[derive(Clone, Debug)]
1141 enum NameBindingKind<'a> {
1142 Def(Def, /* is_macro_export */ bool),
1145 binding: &'a NameBinding<'a>,
1146 directive: &'a ImportDirective<'a>,
1150 b1: &'a NameBinding<'a>,
1151 b2: &'a NameBinding<'a>,
1155 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1157 struct UseError<'a> {
1158 err: DiagnosticBuilder<'a>,
1159 /// Attach `use` statements for these candidates
1160 candidates: Vec<ImportSuggestion>,
1161 /// The node id of the module to place the use statements in
1163 /// Whether the diagnostic should state that it's "better"
1167 struct AmbiguityError<'a> {
1169 b1: &'a NameBinding<'a>,
1170 b2: &'a NameBinding<'a>,
1173 impl<'a> NameBinding<'a> {
1174 fn module(&self) -> Option<Module<'a>> {
1176 NameBindingKind::Module(module) => Some(module),
1177 NameBindingKind::Import { binding, .. } => binding.module(),
1182 fn def(&self) -> Def {
1184 NameBindingKind::Def(def, _) => def,
1185 NameBindingKind::Module(module) => module.def().unwrap(),
1186 NameBindingKind::Import { binding, .. } => binding.def(),
1187 NameBindingKind::Ambiguity { .. } => Def::Err,
1191 fn def_ignoring_ambiguity(&self) -> Def {
1193 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1194 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1199 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1200 resolver.get_macro(self.def_ignoring_ambiguity())
1203 // We sometimes need to treat variants as `pub` for backwards compatibility
1204 fn pseudo_vis(&self) -> ty::Visibility {
1205 if self.is_variant() && self.def().def_id().is_local() {
1206 ty::Visibility::Public
1212 fn is_variant(&self) -> bool {
1214 NameBindingKind::Def(Def::Variant(..), _) |
1215 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1220 fn is_extern_crate(&self) -> bool {
1222 NameBindingKind::Import {
1223 directive: &ImportDirective {
1224 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1231 fn is_import(&self) -> bool {
1233 NameBindingKind::Import { .. } => true,
1238 fn is_renamed_extern_crate(&self) -> bool {
1239 if let NameBindingKind::Import { directive, ..} = self.kind {
1240 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1247 fn is_glob_import(&self) -> bool {
1249 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1250 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1255 fn is_importable(&self) -> bool {
1257 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1262 fn is_macro_def(&self) -> bool {
1264 NameBindingKind::Def(Def::Macro(..), _) => true,
1269 fn macro_kind(&self) -> Option<MacroKind> {
1270 match self.def_ignoring_ambiguity() {
1271 Def::Macro(_, kind) => Some(kind),
1272 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1277 fn descr(&self) -> &'static str {
1278 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1281 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1282 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1283 // Then this function returns `true` if `self` may emerge from a macro *after* that
1284 // in some later round and screw up our previously found resolution.
1285 // See more detailed explanation in
1286 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1287 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1288 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1289 // Expansions are partially ordered, so "may appear after" is an inversion of
1290 // "certainly appears before or simultaneously" and includes unordered cases.
1291 let self_parent_expansion = self.expansion;
1292 let other_parent_expansion = binding.expansion;
1293 let certainly_before_other_or_simultaneously =
1294 other_parent_expansion.is_descendant_of(self_parent_expansion);
1295 let certainly_before_invoc_or_simultaneously =
1296 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1297 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1301 /// Interns the names of the primitive types.
1303 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1304 /// special handling, since they have no place of origin.
1305 struct PrimitiveTypeTable {
1306 primitive_types: FxHashMap<Name, PrimTy>,
1309 impl PrimitiveTypeTable {
1310 fn new() -> PrimitiveTypeTable {
1311 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1313 table.intern("bool", Bool);
1314 table.intern("char", Char);
1315 table.intern("f32", Float(FloatTy::F32));
1316 table.intern("f64", Float(FloatTy::F64));
1317 table.intern("isize", Int(IntTy::Isize));
1318 table.intern("i8", Int(IntTy::I8));
1319 table.intern("i16", Int(IntTy::I16));
1320 table.intern("i32", Int(IntTy::I32));
1321 table.intern("i64", Int(IntTy::I64));
1322 table.intern("i128", Int(IntTy::I128));
1323 table.intern("str", Str);
1324 table.intern("usize", Uint(UintTy::Usize));
1325 table.intern("u8", Uint(UintTy::U8));
1326 table.intern("u16", Uint(UintTy::U16));
1327 table.intern("u32", Uint(UintTy::U32));
1328 table.intern("u64", Uint(UintTy::U64));
1329 table.intern("u128", Uint(UintTy::U128));
1333 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1334 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1338 /// The main resolver class.
1340 /// This is the visitor that walks the whole crate.
1341 pub struct Resolver<'a, 'b: 'a> {
1342 session: &'a Session,
1345 pub definitions: Definitions,
1347 graph_root: Module<'a>,
1349 prelude: Option<Module<'a>>,
1350 extern_prelude: FxHashSet<Name>,
1352 /// n.b. This is used only for better diagnostics, not name resolution itself.
1353 has_self: FxHashSet<DefId>,
1355 /// Names of fields of an item `DefId` accessible with dot syntax.
1356 /// Used for hints during error reporting.
1357 field_names: FxHashMap<DefId, Vec<Name>>,
1359 /// All imports known to succeed or fail.
1360 determined_imports: Vec<&'a ImportDirective<'a>>,
1362 /// All non-determined imports.
1363 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1365 /// The module that represents the current item scope.
1366 current_module: Module<'a>,
1368 /// The current set of local scopes for types and values.
1369 /// FIXME #4948: Reuse ribs to avoid allocation.
1370 ribs: PerNS<Vec<Rib<'a>>>,
1372 /// The current set of local scopes, for labels.
1373 label_ribs: Vec<Rib<'a>>,
1375 /// The trait that the current context can refer to.
1376 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1378 /// The current self type if inside an impl (used for better errors).
1379 current_self_type: Option<Ty>,
1381 /// The idents for the primitive types.
1382 primitive_type_table: PrimitiveTypeTable,
1385 import_map: ImportMap,
1386 pub freevars: FreevarMap,
1387 freevars_seen: NodeMap<NodeMap<usize>>,
1388 pub export_map: ExportMap,
1389 pub trait_map: TraitMap,
1391 /// A map from nodes to anonymous modules.
1392 /// Anonymous modules are pseudo-modules that are implicitly created around items
1393 /// contained within blocks.
1395 /// For example, if we have this:
1403 /// There will be an anonymous module created around `g` with the ID of the
1404 /// entry block for `f`.
1405 block_map: NodeMap<Module<'a>>,
1406 module_map: FxHashMap<DefId, Module<'a>>,
1407 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1409 pub make_glob_map: bool,
1410 /// Maps imports to the names of items actually imported (this actually maps
1411 /// all imports, but only glob imports are actually interesting).
1412 pub glob_map: GlobMap,
1414 used_imports: FxHashSet<(NodeId, Namespace)>,
1415 pub maybe_unused_trait_imports: NodeSet,
1416 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1418 /// A list of labels as of yet unused. Labels will be removed from this map when
1419 /// they are used (in a `break` or `continue` statement)
1420 pub unused_labels: FxHashMap<NodeId, Span>,
1422 /// privacy errors are delayed until the end in order to deduplicate them
1423 privacy_errors: Vec<PrivacyError<'a>>,
1424 /// ambiguity errors are delayed for deduplication
1425 ambiguity_errors: Vec<AmbiguityError<'a>>,
1426 /// `use` injections are delayed for better placement and deduplication
1427 use_injections: Vec<UseError<'a>>,
1428 /// `use` injections for proc macros wrongly imported with #[macro_use]
1429 proc_mac_errors: Vec<macros::ProcMacError>,
1430 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1431 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1433 arenas: &'a ResolverArenas<'a>,
1434 dummy_binding: &'a NameBinding<'a>,
1436 crate_loader: &'a mut CrateLoader<'b>,
1437 macro_names: FxHashSet<Ident>,
1438 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1439 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1440 pub all_macros: FxHashMap<Name, Def>,
1441 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1442 macro_defs: FxHashMap<Mark, DefId>,
1443 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1444 pub whitelisted_legacy_custom_derives: Vec<Name>,
1445 pub found_unresolved_macro: bool,
1447 /// List of crate local macros that we need to warn about as being unused.
1448 /// Right now this only includes macro_rules! macros, and macros 2.0.
1449 unused_macros: FxHashSet<DefId>,
1451 /// Maps the `Mark` of an expansion to its containing module or block.
1452 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1454 /// Avoid duplicated errors for "name already defined".
1455 name_already_seen: FxHashMap<Name, Span>,
1457 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1458 warned_proc_macros: FxHashSet<Name>,
1460 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1462 /// This table maps struct IDs into struct constructor IDs,
1463 /// it's not used during normal resolution, only for better error reporting.
1464 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1466 /// Only used for better errors on `fn(): fn()`
1467 current_type_ascription: Vec<Span>,
1469 injected_crate: Option<Module<'a>>,
1471 /// Only supposed to be used by rustdoc, otherwise should be false.
1472 pub ignore_extern_prelude_feature: bool,
1475 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1476 pub struct ResolverArenas<'a> {
1477 modules: arena::TypedArena<ModuleData<'a>>,
1478 local_modules: RefCell<Vec<Module<'a>>>,
1479 name_bindings: arena::TypedArena<NameBinding<'a>>,
1480 import_directives: arena::TypedArena<ImportDirective<'a>>,
1481 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1482 invocation_data: arena::TypedArena<InvocationData<'a>>,
1483 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1486 impl<'a> ResolverArenas<'a> {
1487 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1488 let module = self.modules.alloc(module);
1489 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1490 self.local_modules.borrow_mut().push(module);
1494 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1495 self.local_modules.borrow()
1497 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1498 self.name_bindings.alloc(name_binding)
1500 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1501 -> &'a ImportDirective {
1502 self.import_directives.alloc(import_directive)
1504 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1505 self.name_resolutions.alloc(Default::default())
1507 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1508 -> &'a InvocationData<'a> {
1509 self.invocation_data.alloc(expansion_data)
1511 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1512 self.legacy_bindings.alloc(binding)
1516 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1517 fn parent(self, id: DefId) -> Option<DefId> {
1519 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1520 _ => self.cstore.def_key(id).parent,
1521 }.map(|index| DefId { index, ..id })
1525 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1526 /// the resolver is no longer needed as all the relevant information is inline.
1527 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1528 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1529 self.resolve_hir_path_cb(path, is_value,
1530 |resolver, span, error| resolve_error(resolver, span, error))
1533 fn resolve_str_path(
1536 crate_root: Option<&str>,
1537 components: &[&str],
1538 args: Option<P<hir::GenericArgs>>,
1541 let mut segments = iter::once(keywords::CrateRoot.ident())
1543 crate_root.into_iter()
1544 .chain(components.iter().cloned())
1545 .map(Ident::from_str)
1546 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1548 if let Some(args) = args {
1549 let ident = segments.last().unwrap().ident;
1550 *segments.last_mut().unwrap() = hir::PathSegment {
1557 let mut path = hir::Path {
1560 segments: segments.into(),
1563 self.resolve_hir_path(&mut path, is_value);
1567 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1568 self.def_map.get(&id).cloned()
1571 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1572 self.import_map.get(&id).cloned().unwrap_or_default()
1575 fn definitions(&mut self) -> &mut Definitions {
1576 &mut self.definitions
1580 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1581 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1582 /// isn't something that can be returned because it can't be made to live that long,
1583 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1584 /// just that an error occurred.
1585 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1586 -> Result<hir::Path, ()> {
1588 let mut errored = false;
1590 let mut path = if path_str.starts_with("::") {
1594 segments: iter::once(keywords::CrateRoot.ident()).chain({
1595 path_str.split("::").skip(1).map(Ident::from_str)
1596 }).map(hir::PathSegment::from_ident).collect(),
1602 segments: path_str.split("::").map(Ident::from_str)
1603 .map(hir::PathSegment::from_ident).collect(),
1606 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1607 if errored || path.def == Def::Err {
1614 /// resolve_hir_path, but takes a callback in case there was an error
1615 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1616 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1618 let namespace = if is_value { ValueNS } else { TypeNS };
1619 let hir::Path { ref segments, span, ref mut def } = *path;
1620 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1621 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1622 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1623 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1624 *def = module.def().unwrap(),
1625 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1626 *def = path_res.base_def(),
1627 PathResult::NonModule(..) => match self.resolve_path(
1635 PathResult::Failed(span, msg, _) => {
1636 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1640 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1641 PathResult::Indeterminate => unreachable!(),
1642 PathResult::Failed(span, msg, _) => {
1643 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1649 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1650 pub fn new(session: &'a Session,
1654 make_glob_map: MakeGlobMap,
1655 crate_loader: &'a mut CrateLoader<'crateloader>,
1656 arenas: &'a ResolverArenas<'a>)
1657 -> Resolver<'a, 'crateloader> {
1658 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1659 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1660 let graph_root = arenas.alloc_module(ModuleData {
1661 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1662 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1664 let mut module_map = FxHashMap();
1665 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1667 let mut definitions = Definitions::new();
1668 DefCollector::new(&mut definitions, Mark::root())
1669 .collect_root(crate_name, session.local_crate_disambiguator());
1671 let mut extern_prelude: FxHashSet<Name> =
1672 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1673 if !attr::contains_name(&krate.attrs, "no_core") {
1674 if !attr::contains_name(&krate.attrs, "no_std") {
1675 extern_prelude.insert(Symbol::intern("std"));
1677 extern_prelude.insert(Symbol::intern("core"));
1681 let mut invocations = FxHashMap();
1682 invocations.insert(Mark::root(),
1683 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1685 let mut macro_defs = FxHashMap();
1686 macro_defs.insert(Mark::root(), root_def_id);
1695 // The outermost module has def ID 0; this is not reflected in the
1701 has_self: FxHashSet(),
1702 field_names: FxHashMap(),
1704 determined_imports: Vec::new(),
1705 indeterminate_imports: Vec::new(),
1707 current_module: graph_root,
1709 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1710 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1711 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1713 label_ribs: Vec::new(),
1715 current_trait_ref: None,
1716 current_self_type: None,
1718 primitive_type_table: PrimitiveTypeTable::new(),
1721 import_map: NodeMap(),
1722 freevars: NodeMap(),
1723 freevars_seen: NodeMap(),
1724 export_map: FxHashMap(),
1725 trait_map: NodeMap(),
1727 block_map: NodeMap(),
1728 extern_module_map: FxHashMap(),
1730 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1731 glob_map: NodeMap(),
1733 used_imports: FxHashSet(),
1734 maybe_unused_trait_imports: NodeSet(),
1735 maybe_unused_extern_crates: Vec::new(),
1737 unused_labels: FxHashMap(),
1739 privacy_errors: Vec::new(),
1740 ambiguity_errors: Vec::new(),
1741 use_injections: Vec::new(),
1742 proc_mac_errors: Vec::new(),
1743 macro_expanded_macro_export_errors: BTreeSet::new(),
1746 dummy_binding: arenas.alloc_name_binding(NameBinding {
1747 kind: NameBindingKind::Def(Def::Err, false),
1748 expansion: Mark::root(),
1750 vis: ty::Visibility::Public,
1754 macro_names: FxHashSet(),
1755 builtin_macros: FxHashMap(),
1756 macro_use_prelude: FxHashMap(),
1757 all_macros: FxHashMap(),
1758 macro_map: FxHashMap(),
1761 local_macro_def_scopes: FxHashMap(),
1762 name_already_seen: FxHashMap(),
1763 whitelisted_legacy_custom_derives: Vec::new(),
1764 warned_proc_macros: FxHashSet(),
1765 potentially_unused_imports: Vec::new(),
1766 struct_constructors: DefIdMap(),
1767 found_unresolved_macro: false,
1768 unused_macros: FxHashSet(),
1769 current_type_ascription: Vec::new(),
1770 injected_crate: None,
1771 ignore_extern_prelude_feature: false,
1775 pub fn arenas() -> ResolverArenas<'a> {
1777 modules: arena::TypedArena::new(),
1778 local_modules: RefCell::new(Vec::new()),
1779 name_bindings: arena::TypedArena::new(),
1780 import_directives: arena::TypedArena::new(),
1781 name_resolutions: arena::TypedArena::new(),
1782 invocation_data: arena::TypedArena::new(),
1783 legacy_bindings: arena::TypedArena::new(),
1787 /// Runs the function on each namespace.
1788 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1794 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1796 match self.macro_defs.get(&ctxt.outer()) {
1797 Some(&def_id) => return def_id,
1798 None => ctxt.remove_mark(),
1803 /// Entry point to crate resolution.
1804 pub fn resolve_crate(&mut self, krate: &Crate) {
1805 ImportResolver { resolver: self }.finalize_imports();
1806 self.current_module = self.graph_root;
1807 self.finalize_current_module_macro_resolutions();
1809 visit::walk_crate(self, krate);
1811 check_unused::check_crate(self, krate);
1812 self.report_errors(krate);
1813 self.crate_loader.postprocess(krate);
1820 normal_ancestor_id: DefId,
1824 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1825 self.arenas.alloc_module(module)
1828 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1829 -> bool /* true if an error was reported */ {
1830 match binding.kind {
1831 NameBindingKind::Import { directive, binding, ref used }
1834 directive.used.set(true);
1835 self.used_imports.insert((directive.id, ns));
1836 self.add_to_glob_map(directive.id, ident);
1837 self.record_use(ident, ns, binding)
1839 NameBindingKind::Import { .. } => false,
1840 NameBindingKind::Ambiguity { b1, b2 } => {
1841 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1848 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1849 if self.make_glob_map {
1850 self.glob_map.entry(id).or_default().insert(ident.name);
1854 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1855 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1856 /// `ident` in the first scope that defines it (or None if no scopes define it).
1858 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1859 /// the items are defined in the block. For example,
1862 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1865 /// g(); // This resolves to the local variable `g` since it shadows the item.
1869 /// Invariant: This must only be called during main resolution, not during
1870 /// import resolution.
1871 fn resolve_ident_in_lexical_scope(&mut self,
1874 record_used_id: Option<NodeId>,
1876 -> Option<LexicalScopeBinding<'a>> {
1877 let record_used = record_used_id.is_some();
1878 assert!(ns == TypeNS || ns == ValueNS);
1880 ident.span = if ident.name == keywords::SelfType.name() {
1881 // FIXME(jseyfried) improve `Self` hygiene
1882 ident.span.with_ctxt(SyntaxContext::empty())
1887 ident = ident.modern_and_legacy();
1890 // Walk backwards up the ribs in scope.
1891 let mut module = self.graph_root;
1892 for i in (0 .. self.ribs[ns].len()).rev() {
1893 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1894 // The ident resolves to a type parameter or local variable.
1895 return Some(LexicalScopeBinding::Def(
1896 self.adjust_local_def(ns, i, def, record_used, path_span)
1900 module = match self.ribs[ns][i].kind {
1901 ModuleRibKind(module) => module,
1902 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1903 // If an invocation of this macro created `ident`, give up on `ident`
1904 // and switch to `ident`'s source from the macro definition.
1905 ident.span.remove_mark();
1911 let item = self.resolve_ident_in_module_unadjusted(
1912 ModuleOrUniformRoot::Module(module),
1919 if let Ok(binding) = item {
1920 // The ident resolves to an item.
1921 return Some(LexicalScopeBinding::Item(binding));
1925 ModuleKind::Block(..) => {}, // We can see through blocks
1930 ident.span = ident.span.modern();
1931 let mut poisoned = None;
1933 let opt_module = if let Some(node_id) = record_used_id {
1934 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1935 node_id, &mut poisoned)
1937 self.hygienic_lexical_parent(module, &mut ident.span)
1939 module = unwrap_or!(opt_module, break);
1940 let orig_current_module = self.current_module;
1941 self.current_module = module; // Lexical resolutions can never be a privacy error.
1942 let result = self.resolve_ident_in_module_unadjusted(
1943 ModuleOrUniformRoot::Module(module),
1950 self.current_module = orig_current_module;
1954 if let Some(node_id) = poisoned {
1955 self.session.buffer_lint_with_diagnostic(
1956 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1957 node_id, ident.span,
1958 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1959 lint::builtin::BuiltinLintDiagnostics::
1960 ProcMacroDeriveResolutionFallback(ident.span),
1963 return Some(LexicalScopeBinding::Item(binding))
1965 Err(Determined) => continue,
1966 Err(Undetermined) =>
1967 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1971 if !module.no_implicit_prelude {
1972 // `record_used` means that we don't try to load crates during speculative resolution
1973 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1974 if !self.session.features_untracked().extern_prelude &&
1975 !self.ignore_extern_prelude_feature {
1976 feature_err(&self.session.parse_sess, "extern_prelude",
1977 ident.span, GateIssue::Language,
1978 "access to extern crates through prelude is experimental").emit();
1981 let crate_root = self.load_extern_prelude_crate_if_needed(ident);
1983 let binding = (crate_root, ty::Visibility::Public,
1984 ident.span, Mark::root()).to_name_binding(self.arenas);
1985 return Some(LexicalScopeBinding::Item(binding));
1987 if ns == TypeNS && is_known_tool(ident.name) {
1988 let binding = (Def::ToolMod, ty::Visibility::Public,
1989 ident.span, Mark::root()).to_name_binding(self.arenas);
1990 return Some(LexicalScopeBinding::Item(binding));
1992 if let Some(prelude) = self.prelude {
1993 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1994 ModuleOrUniformRoot::Module(prelude),
2001 return Some(LexicalScopeBinding::Item(binding));
2009 fn load_extern_prelude_crate_if_needed(&mut self, ident: Ident) -> Module<'a> {
2010 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
2011 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2012 self.populate_module_if_necessary(&crate_root);
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_item(&mut self, item: &Item) {
2208 let name = item.ident.name;
2209 debug!("(resolving item) resolving {}", name);
2212 ItemKind::Ty(_, ref generics) |
2213 ItemKind::Fn(_, _, ref generics, _) |
2214 ItemKind::Existential(_, ref generics) => {
2215 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2216 |this| visit::walk_item(this, item));
2219 ItemKind::Enum(_, ref generics) |
2220 ItemKind::Struct(_, ref generics) |
2221 ItemKind::Union(_, ref generics) => {
2222 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2223 let item_def_id = this.definitions.local_def_id(item.id);
2224 if this.session.features_untracked().self_in_typedefs {
2225 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2226 visit::walk_item(this, item);
2229 visit::walk_item(this, item);
2234 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2235 self.resolve_implementation(generics,
2241 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2242 // Create a new rib for the trait-wide type parameters.
2243 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2244 let local_def_id = this.definitions.local_def_id(item.id);
2245 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2246 this.visit_generics(generics);
2247 walk_list!(this, visit_param_bound, bounds);
2249 for trait_item in trait_items {
2250 let type_parameters = HasTypeParameters(&trait_item.generics,
2251 TraitOrImplItemRibKind);
2252 this.with_type_parameter_rib(type_parameters, |this| {
2253 match trait_item.node {
2254 TraitItemKind::Const(ref ty, ref default) => {
2257 // Only impose the restrictions of
2258 // ConstRibKind for an actual constant
2259 // expression in a provided default.
2260 if let Some(ref expr) = *default{
2261 this.with_constant_rib(|this| {
2262 this.visit_expr(expr);
2266 TraitItemKind::Method(_, _) => {
2267 visit::walk_trait_item(this, trait_item)
2269 TraitItemKind::Type(..) => {
2270 visit::walk_trait_item(this, trait_item)
2272 TraitItemKind::Macro(_) => {
2273 panic!("unexpanded macro in resolve!")
2282 ItemKind::TraitAlias(ref generics, ref bounds) => {
2283 // Create a new rib for the trait-wide type parameters.
2284 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2285 let local_def_id = this.definitions.local_def_id(item.id);
2286 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2287 this.visit_generics(generics);
2288 walk_list!(this, visit_param_bound, bounds);
2293 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2294 self.with_scope(item.id, |this| {
2295 visit::walk_item(this, item);
2299 ItemKind::Static(ref ty, _, ref expr) |
2300 ItemKind::Const(ref ty, ref expr) => {
2301 self.with_item_rib(|this| {
2303 this.with_constant_rib(|this| {
2304 this.visit_expr(expr);
2309 ItemKind::Use(ref use_tree) => {
2310 // Imports are resolved as global by default, add starting root segment.
2312 segments: use_tree.prefix.make_root().into_iter().collect(),
2313 span: use_tree.span,
2315 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2318 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2319 // do nothing, these are just around to be encoded
2322 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2326 /// For the most part, use trees are desugared into `ImportDirective` instances
2327 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2328 /// there is one special case we handle here: an empty nested import like
2329 /// `a::{b::{}}`, which desugares into...no import directives.
2330 fn resolve_use_tree(
2335 use_tree: &ast::UseTree,
2338 match use_tree.kind {
2339 ast::UseTreeKind::Nested(ref items) => {
2341 segments: prefix.segments
2343 .chain(use_tree.prefix.segments.iter())
2346 span: prefix.span.to(use_tree.prefix.span),
2349 if items.len() == 0 {
2350 // Resolve prefix of an import with empty braces (issue #28388).
2351 self.smart_resolve_path_with_crate_lint(
2355 PathSource::ImportPrefix,
2356 CrateLint::UsePath { root_id, root_span },
2359 for &(ref tree, nested_id) in items {
2360 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2364 ast::UseTreeKind::Simple(..) => {},
2365 ast::UseTreeKind::Glob => {},
2369 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2370 where F: FnOnce(&mut Resolver)
2372 match type_parameters {
2373 HasTypeParameters(generics, rib_kind) => {
2374 let mut function_type_rib = Rib::new(rib_kind);
2375 let mut seen_bindings = FxHashMap();
2376 for param in &generics.params {
2378 GenericParamKind::Lifetime { .. } => {}
2379 GenericParamKind::Type { .. } => {
2380 let ident = param.ident.modern();
2381 debug!("with_type_parameter_rib: {}", param.id);
2383 if seen_bindings.contains_key(&ident) {
2384 let span = seen_bindings.get(&ident).unwrap();
2385 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2389 resolve_error(self, param.ident.span, err);
2391 seen_bindings.entry(ident).or_insert(param.ident.span);
2393 // Plain insert (no renaming).
2394 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2395 function_type_rib.bindings.insert(ident, def);
2396 self.record_def(param.id, PathResolution::new(def));
2400 self.ribs[TypeNS].push(function_type_rib);
2403 NoTypeParameters => {
2410 if let HasTypeParameters(..) = type_parameters {
2411 self.ribs[TypeNS].pop();
2415 fn with_label_rib<F>(&mut self, f: F)
2416 where F: FnOnce(&mut Resolver)
2418 self.label_ribs.push(Rib::new(NormalRibKind));
2420 self.label_ribs.pop();
2423 fn with_item_rib<F>(&mut self, f: F)
2424 where F: FnOnce(&mut Resolver)
2426 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2427 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2429 self.ribs[TypeNS].pop();
2430 self.ribs[ValueNS].pop();
2433 fn with_constant_rib<F>(&mut self, f: F)
2434 where F: FnOnce(&mut Resolver)
2436 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2437 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2439 self.label_ribs.pop();
2440 self.ribs[ValueNS].pop();
2443 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2444 where F: FnOnce(&mut Resolver) -> T
2446 // Handle nested impls (inside fn bodies)
2447 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2448 let result = f(self);
2449 self.current_self_type = previous_value;
2453 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2454 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2455 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2457 let mut new_val = None;
2458 let mut new_id = None;
2459 if let Some(trait_ref) = opt_trait_ref {
2460 let path: Vec<_> = trait_ref.path.segments.iter()
2461 .map(|seg| seg.ident)
2463 let def = self.smart_resolve_path_fragment(
2467 trait_ref.path.span,
2468 PathSource::Trait(AliasPossibility::No),
2469 CrateLint::SimplePath(trait_ref.ref_id),
2471 if def != Def::Err {
2472 new_id = Some(def.def_id());
2473 let span = trait_ref.path.span;
2474 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2481 CrateLint::SimplePath(trait_ref.ref_id),
2484 new_val = Some((module, trait_ref.clone()));
2488 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2489 let result = f(self, new_id);
2490 self.current_trait_ref = original_trait_ref;
2494 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2495 where F: FnOnce(&mut Resolver)
2497 let mut self_type_rib = Rib::new(NormalRibKind);
2499 // plain insert (no renaming, types are not currently hygienic....)
2500 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2501 self.ribs[TypeNS].push(self_type_rib);
2503 self.ribs[TypeNS].pop();
2506 fn resolve_implementation(&mut self,
2507 generics: &Generics,
2508 opt_trait_reference: &Option<TraitRef>,
2511 impl_items: &[ImplItem]) {
2512 // If applicable, create a rib for the type parameters.
2513 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2514 // Dummy self type for better errors if `Self` is used in the trait path.
2515 this.with_self_rib(Def::SelfTy(None, None), |this| {
2516 // Resolve the trait reference, if necessary.
2517 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2518 let item_def_id = this.definitions.local_def_id(item_id);
2519 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2520 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2521 // Resolve type arguments in the trait path.
2522 visit::walk_trait_ref(this, trait_ref);
2524 // Resolve the self type.
2525 this.visit_ty(self_type);
2526 // Resolve the type parameters.
2527 this.visit_generics(generics);
2528 // Resolve the items within the impl.
2529 this.with_current_self_type(self_type, |this| {
2530 for impl_item in impl_items {
2531 this.resolve_visibility(&impl_item.vis);
2533 // We also need a new scope for the impl item type parameters.
2534 let type_parameters = HasTypeParameters(&impl_item.generics,
2535 TraitOrImplItemRibKind);
2536 this.with_type_parameter_rib(type_parameters, |this| {
2537 use self::ResolutionError::*;
2538 match impl_item.node {
2539 ImplItemKind::Const(..) => {
2540 // If this is a trait impl, ensure the const
2542 this.check_trait_item(impl_item.ident,
2545 |n, s| ConstNotMemberOfTrait(n, s));
2546 this.with_constant_rib(|this|
2547 visit::walk_impl_item(this, impl_item)
2550 ImplItemKind::Method(..) => {
2551 // If this is a trait impl, ensure the method
2553 this.check_trait_item(impl_item.ident,
2556 |n, s| MethodNotMemberOfTrait(n, s));
2558 visit::walk_impl_item(this, impl_item);
2560 ImplItemKind::Type(ref ty) => {
2561 // If this is a trait impl, ensure the type
2563 this.check_trait_item(impl_item.ident,
2566 |n, s| TypeNotMemberOfTrait(n, s));
2570 ImplItemKind::Existential(ref bounds) => {
2571 // If this is a trait impl, ensure the type
2573 this.check_trait_item(impl_item.ident,
2576 |n, s| TypeNotMemberOfTrait(n, s));
2578 for bound in bounds {
2579 this.visit_param_bound(bound);
2582 ImplItemKind::Macro(_) =>
2583 panic!("unexpanded macro in resolve!"),
2594 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2595 where F: FnOnce(Name, &str) -> ResolutionError
2597 // If there is a TraitRef in scope for an impl, then the method must be in the
2599 if let Some((module, _)) = self.current_trait_ref {
2600 if self.resolve_ident_in_module(
2601 ModuleOrUniformRoot::Module(module),
2607 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2608 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2613 fn resolve_local(&mut self, local: &Local) {
2614 // Resolve the type.
2615 walk_list!(self, visit_ty, &local.ty);
2617 // Resolve the initializer.
2618 walk_list!(self, visit_expr, &local.init);
2620 // Resolve the pattern.
2621 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2624 // build a map from pattern identifiers to binding-info's.
2625 // this is done hygienically. This could arise for a macro
2626 // that expands into an or-pattern where one 'x' was from the
2627 // user and one 'x' came from the macro.
2628 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2629 let mut binding_map = FxHashMap();
2631 pat.walk(&mut |pat| {
2632 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2633 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2634 Some(Def::Local(..)) => true,
2637 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2638 binding_map.insert(ident, binding_info);
2647 // check that all of the arms in an or-pattern have exactly the
2648 // same set of bindings, with the same binding modes for each.
2649 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2650 if pats.is_empty() {
2654 let mut missing_vars = FxHashMap();
2655 let mut inconsistent_vars = FxHashMap();
2656 for (i, p) in pats.iter().enumerate() {
2657 let map_i = self.binding_mode_map(&p);
2659 for (j, q) in pats.iter().enumerate() {
2664 let map_j = self.binding_mode_map(&q);
2665 for (&key, &binding_i) in &map_i {
2666 if map_j.len() == 0 { // Account for missing bindings when
2667 let binding_error = missing_vars // map_j has none.
2669 .or_insert(BindingError {
2671 origin: BTreeSet::new(),
2672 target: BTreeSet::new(),
2674 binding_error.origin.insert(binding_i.span);
2675 binding_error.target.insert(q.span);
2677 for (&key_j, &binding_j) in &map_j {
2678 match map_i.get(&key_j) {
2679 None => { // missing binding
2680 let binding_error = missing_vars
2682 .or_insert(BindingError {
2684 origin: BTreeSet::new(),
2685 target: BTreeSet::new(),
2687 binding_error.origin.insert(binding_j.span);
2688 binding_error.target.insert(p.span);
2690 Some(binding_i) => { // check consistent binding
2691 if binding_i.binding_mode != binding_j.binding_mode {
2694 .or_insert((binding_j.span, binding_i.span));
2702 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2703 missing_vars.sort();
2704 for (_, v) in missing_vars {
2706 *v.origin.iter().next().unwrap(),
2707 ResolutionError::VariableNotBoundInPattern(v));
2709 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2710 inconsistent_vars.sort();
2711 for (name, v) in inconsistent_vars {
2712 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2716 fn resolve_arm(&mut self, arm: &Arm) {
2717 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2719 let mut bindings_list = FxHashMap();
2720 for pattern in &arm.pats {
2721 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2724 // This has to happen *after* we determine which pat_idents are variants
2725 self.check_consistent_bindings(&arm.pats);
2728 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2731 self.visit_expr(&arm.body);
2733 self.ribs[ValueNS].pop();
2736 fn resolve_block(&mut self, block: &Block) {
2737 debug!("(resolving block) entering block");
2738 // Move down in the graph, if there's an anonymous module rooted here.
2739 let orig_module = self.current_module;
2740 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2742 let mut num_macro_definition_ribs = 0;
2743 if let Some(anonymous_module) = anonymous_module {
2744 debug!("(resolving block) found anonymous module, moving down");
2745 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2746 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2747 self.current_module = anonymous_module;
2748 self.finalize_current_module_macro_resolutions();
2750 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2753 // Descend into the block.
2754 for stmt in &block.stmts {
2755 if let ast::StmtKind::Item(ref item) = stmt.node {
2756 if let ast::ItemKind::MacroDef(..) = item.node {
2757 num_macro_definition_ribs += 1;
2758 let def = self.definitions.local_def_id(item.id);
2759 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2760 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2764 self.visit_stmt(stmt);
2768 self.current_module = orig_module;
2769 for _ in 0 .. num_macro_definition_ribs {
2770 self.ribs[ValueNS].pop();
2771 self.label_ribs.pop();
2773 self.ribs[ValueNS].pop();
2774 if anonymous_module.is_some() {
2775 self.ribs[TypeNS].pop();
2777 debug!("(resolving block) leaving block");
2780 fn fresh_binding(&mut self,
2783 outer_pat_id: NodeId,
2784 pat_src: PatternSource,
2785 bindings: &mut FxHashMap<Ident, NodeId>)
2787 // Add the binding to the local ribs, if it
2788 // doesn't already exist in the bindings map. (We
2789 // must not add it if it's in the bindings map
2790 // because that breaks the assumptions later
2791 // passes make about or-patterns.)
2792 let ident = ident.modern_and_legacy();
2793 let mut def = Def::Local(pat_id);
2794 match bindings.get(&ident).cloned() {
2795 Some(id) if id == outer_pat_id => {
2796 // `Variant(a, a)`, error
2800 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2804 Some(..) if pat_src == PatternSource::FnParam => {
2805 // `fn f(a: u8, a: u8)`, error
2809 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2813 Some(..) if pat_src == PatternSource::Match ||
2814 pat_src == PatternSource::IfLet ||
2815 pat_src == PatternSource::WhileLet => {
2816 // `Variant1(a) | Variant2(a)`, ok
2817 // Reuse definition from the first `a`.
2818 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2821 span_bug!(ident.span, "two bindings with the same name from \
2822 unexpected pattern source {:?}", pat_src);
2825 // A completely fresh binding, add to the lists if it's valid.
2826 if ident.name != keywords::Invalid.name() {
2827 bindings.insert(ident, outer_pat_id);
2828 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2833 PathResolution::new(def)
2836 fn resolve_pattern(&mut self,
2838 pat_src: PatternSource,
2839 // Maps idents to the node ID for the
2840 // outermost pattern that binds them.
2841 bindings: &mut FxHashMap<Ident, NodeId>) {
2842 // Visit all direct subpatterns of this pattern.
2843 let outer_pat_id = pat.id;
2844 pat.walk(&mut |pat| {
2846 PatKind::Ident(bmode, ident, ref opt_pat) => {
2847 // First try to resolve the identifier as some existing
2848 // entity, then fall back to a fresh binding.
2849 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2851 .and_then(LexicalScopeBinding::item);
2852 let resolution = binding.map(NameBinding::def).and_then(|def| {
2853 let is_syntactic_ambiguity = opt_pat.is_none() &&
2854 bmode == BindingMode::ByValue(Mutability::Immutable);
2856 Def::StructCtor(_, CtorKind::Const) |
2857 Def::VariantCtor(_, CtorKind::Const) |
2858 Def::Const(..) if is_syntactic_ambiguity => {
2859 // Disambiguate in favor of a unit struct/variant
2860 // or constant pattern.
2861 self.record_use(ident, ValueNS, binding.unwrap());
2862 Some(PathResolution::new(def))
2864 Def::StructCtor(..) | Def::VariantCtor(..) |
2865 Def::Const(..) | Def::Static(..) => {
2866 // This is unambiguously a fresh binding, either syntactically
2867 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2868 // to something unusable as a pattern (e.g. constructor function),
2869 // but we still conservatively report an error, see
2870 // issues/33118#issuecomment-233962221 for one reason why.
2874 ResolutionError::BindingShadowsSomethingUnacceptable(
2875 pat_src.descr(), ident.name, binding.unwrap())
2879 Def::Fn(..) | Def::Err => {
2880 // These entities are explicitly allowed
2881 // to be shadowed by fresh bindings.
2885 span_bug!(ident.span, "unexpected definition for an \
2886 identifier in pattern: {:?}", def);
2889 }).unwrap_or_else(|| {
2890 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2893 self.record_def(pat.id, resolution);
2896 PatKind::TupleStruct(ref path, ..) => {
2897 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2900 PatKind::Path(ref qself, ref path) => {
2901 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2904 PatKind::Struct(ref path, ..) => {
2905 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2913 visit::walk_pat(self, pat);
2916 // High-level and context dependent path resolution routine.
2917 // Resolves the path and records the resolution into definition map.
2918 // If resolution fails tries several techniques to find likely
2919 // resolution candidates, suggest imports or other help, and report
2920 // errors in user friendly way.
2921 fn smart_resolve_path(&mut self,
2923 qself: Option<&QSelf>,
2927 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2930 /// A variant of `smart_resolve_path` where you also specify extra
2931 /// information about where the path came from; this extra info is
2932 /// sometimes needed for the lint that recommends rewriting
2933 /// absolute paths to `crate`, so that it knows how to frame the
2934 /// suggestion. If you are just resolving a path like `foo::bar`
2935 /// that appears...somewhere, though, then you just want
2936 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2937 /// already provides.
2938 fn smart_resolve_path_with_crate_lint(
2941 qself: Option<&QSelf>,
2944 crate_lint: CrateLint
2945 ) -> PathResolution {
2946 let segments = &path.segments.iter()
2947 .map(|seg| seg.ident)
2948 .collect::<Vec<_>>();
2949 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2952 fn smart_resolve_path_fragment(&mut self,
2954 qself: Option<&QSelf>,
2958 crate_lint: CrateLint)
2960 let ident_span = path.last().map_or(span, |ident| ident.span);
2961 let ns = source.namespace();
2962 let is_expected = &|def| source.is_expected(def);
2963 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2965 // Base error is amended with one short label and possibly some longer helps/notes.
2966 let report_errors = |this: &mut Self, def: Option<Def>| {
2967 // Make the base error.
2968 let expected = source.descr_expected();
2969 let path_str = names_to_string(path);
2970 let code = source.error_code(def.is_some());
2971 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2972 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2973 format!("not a {}", expected),
2976 let item_str = path[path.len() - 1];
2977 let item_span = path[path.len() - 1].span;
2978 let (mod_prefix, mod_str) = if path.len() == 1 {
2979 (String::new(), "this scope".to_string())
2980 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2981 (String::new(), "the crate root".to_string())
2983 let mod_path = &path[..path.len() - 1];
2984 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2985 false, span, CrateLint::No) {
2986 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
2989 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
2990 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2992 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2993 format!("not found in {}", mod_str),
2996 let code = DiagnosticId::Error(code.into());
2997 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2999 // Emit special messages for unresolved `Self` and `self`.
3000 if is_self_type(path, ns) {
3001 __diagnostic_used!(E0411);
3002 err.code(DiagnosticId::Error("E0411".into()));
3003 let available_in = if this.session.features_untracked().self_in_typedefs {
3004 "impls, traits, and type definitions"
3008 err.span_label(span, format!("`Self` is only available in {}", available_in));
3009 return (err, Vec::new());
3011 if is_self_value(path, ns) {
3012 __diagnostic_used!(E0424);
3013 err.code(DiagnosticId::Error("E0424".into()));
3014 err.span_label(span, format!("`self` value is only available in \
3015 methods with `self` parameter"));
3016 return (err, Vec::new());
3019 // Try to lookup the name in more relaxed fashion for better error reporting.
3020 let ident = *path.last().unwrap();
3021 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3022 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3023 let enum_candidates =
3024 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3025 let mut enum_candidates = enum_candidates.iter()
3026 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3027 enum_candidates.sort();
3028 for (sp, variant_path, enum_path) in enum_candidates {
3030 let msg = format!("there is an enum variant `{}`, \
3036 err.span_suggestion_with_applicability(
3038 "you can try using the variant's enum",
3040 Applicability::MachineApplicable,
3045 if path.len() == 1 && this.self_type_is_available(span) {
3046 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3047 let self_is_available = this.self_value_is_available(path[0].span, span);
3049 AssocSuggestion::Field => {
3050 err.span_suggestion_with_applicability(
3053 format!("self.{}", path_str),
3054 Applicability::MachineApplicable,
3056 if !self_is_available {
3057 err.span_label(span, format!("`self` value is only available in \
3058 methods with `self` parameter"));
3061 AssocSuggestion::MethodWithSelf if self_is_available => {
3062 err.span_suggestion_with_applicability(
3065 format!("self.{}", path_str),
3066 Applicability::MachineApplicable,
3069 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3070 err.span_suggestion_with_applicability(
3073 format!("Self::{}", path_str),
3074 Applicability::MachineApplicable,
3078 return (err, candidates);
3082 let mut levenshtein_worked = false;
3085 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3086 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3087 levenshtein_worked = true;
3090 // Try context dependent help if relaxed lookup didn't work.
3091 if let Some(def) = def {
3092 match (def, source) {
3093 (Def::Macro(..), _) => {
3094 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3095 return (err, candidates);
3097 (Def::TyAlias(..), PathSource::Trait(_)) => {
3098 err.span_label(span, "type aliases cannot be used for traits");
3099 return (err, candidates);
3101 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3102 ExprKind::Field(_, ident) => {
3103 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3105 return (err, candidates);
3107 ExprKind::MethodCall(ref segment, ..) => {
3108 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3109 path_str, segment.ident));
3110 return (err, candidates);
3114 (Def::Enum(..), PathSource::TupleStruct)
3115 | (Def::Enum(..), PathSource::Expr(..)) => {
3116 if let Some(variants) = this.collect_enum_variants(def) {
3117 err.note(&format!("did you mean to use one \
3118 of the following variants?\n{}",
3120 .map(|suggestion| path_names_to_string(suggestion))
3121 .map(|suggestion| format!("- `{}`", suggestion))
3122 .collect::<Vec<_>>()
3126 err.note("did you mean to use one of the enum's variants?");
3128 return (err, candidates);
3130 (Def::Struct(def_id), _) if ns == ValueNS => {
3131 if let Some((ctor_def, ctor_vis))
3132 = this.struct_constructors.get(&def_id).cloned() {
3133 let accessible_ctor = this.is_accessible(ctor_vis);
3134 if is_expected(ctor_def) && !accessible_ctor {
3135 err.span_label(span, format!("constructor is not visible \
3136 here due to private fields"));
3139 // HACK(estebank): find a better way to figure out that this was a
3140 // parser issue where a struct literal is being used on an expression
3141 // where a brace being opened means a block is being started. Look
3142 // ahead for the next text to see if `span` is followed by a `{`.
3143 let cm = this.session.source_map();
3146 sp = cm.next_point(sp);
3147 match cm.span_to_snippet(sp) {
3148 Ok(ref snippet) => {
3149 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3156 let followed_by_brace = match cm.span_to_snippet(sp) {
3157 Ok(ref snippet) if snippet == "{" => true,
3160 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3163 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3168 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3172 return (err, candidates);
3174 (Def::Union(..), _) |
3175 (Def::Variant(..), _) |
3176 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3177 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3179 return (err, candidates);
3181 (Def::SelfTy(..), _) if ns == ValueNS => {
3182 err.span_label(span, fallback_label);
3183 err.note("can't use `Self` as a constructor, you must use the \
3184 implemented struct");
3185 return (err, candidates);
3187 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3188 err.note("can't use a type alias as a constructor");
3189 return (err, candidates);
3196 if !levenshtein_worked {
3197 err.span_label(base_span, fallback_label);
3198 this.type_ascription_suggestion(&mut err, base_span);
3202 let report_errors = |this: &mut Self, def: Option<Def>| {
3203 let (err, candidates) = report_errors(this, def);
3204 let def_id = this.current_module.normal_ancestor_id;
3205 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3206 let better = def.is_some();
3207 this.use_injections.push(UseError { err, candidates, node_id, better });
3208 err_path_resolution()
3211 let resolution = match self.resolve_qpath_anywhere(
3217 source.defer_to_typeck(),
3218 source.global_by_default(),
3221 Some(resolution) if resolution.unresolved_segments() == 0 => {
3222 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3225 // Add a temporary hack to smooth the transition to new struct ctor
3226 // visibility rules. See #38932 for more details.
3228 if let Def::Struct(def_id) = resolution.base_def() {
3229 if let Some((ctor_def, ctor_vis))
3230 = self.struct_constructors.get(&def_id).cloned() {
3231 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3232 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3233 self.session.buffer_lint(lint, id, span,
3234 "private struct constructors are not usable through \
3235 re-exports in outer modules",
3237 res = Some(PathResolution::new(ctor_def));
3242 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3245 Some(resolution) if source.defer_to_typeck() => {
3246 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3247 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3248 // it needs to be added to the trait map.
3250 let item_name = *path.last().unwrap();
3251 let traits = self.get_traits_containing_item(item_name, ns);
3252 self.trait_map.insert(id, traits);
3256 _ => report_errors(self, None)
3259 if let PathSource::TraitItem(..) = source {} else {
3260 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3261 self.record_def(id, resolution);
3266 fn type_ascription_suggestion(&self,
3267 err: &mut DiagnosticBuilder,
3269 debug!("type_ascription_suggetion {:?}", base_span);
3270 let cm = self.session.source_map();
3271 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3272 if let Some(sp) = self.current_type_ascription.last() {
3274 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3275 sp = cm.next_point(sp);
3276 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3277 debug!("snippet {:?}", snippet);
3278 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3279 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3280 debug!("{:?} {:?}", line_sp, line_base_sp);
3282 err.span_label(base_span,
3283 "expecting a type here because of type ascription");
3284 if line_sp != line_base_sp {
3285 err.span_suggestion_short(sp,
3286 "did you mean to use `;` here instead?",
3290 } else if snippet.trim().len() != 0 {
3291 debug!("tried to find type ascription `:` token, couldn't find it");
3301 fn self_type_is_available(&mut self, span: Span) -> bool {
3302 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3303 TypeNS, None, span);
3304 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3307 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3308 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3309 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3310 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3313 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3314 fn resolve_qpath_anywhere(&mut self,
3316 qself: Option<&QSelf>,
3318 primary_ns: Namespace,
3320 defer_to_typeck: bool,
3321 global_by_default: bool,
3322 crate_lint: CrateLint)
3323 -> Option<PathResolution> {
3324 let mut fin_res = None;
3325 // FIXME: can't resolve paths in macro namespace yet, macros are
3326 // processed by the little special hack below.
3327 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3328 if i == 0 || ns != primary_ns {
3329 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3330 // If defer_to_typeck, then resolution > no resolution,
3331 // otherwise full resolution > partial resolution > no resolution.
3332 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3334 res => if fin_res.is_none() { fin_res = res },
3338 if primary_ns != MacroNS &&
3339 (self.macro_names.contains(&path[0].modern()) ||
3340 self.builtin_macros.get(&path[0].name).cloned()
3341 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3342 self.macro_use_prelude.get(&path[0].name).cloned()
3343 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3344 // Return some dummy definition, it's enough for error reporting.
3346 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3352 /// Handles paths that may refer to associated items.
3353 fn resolve_qpath(&mut self,
3355 qself: Option<&QSelf>,
3359 global_by_default: bool,
3360 crate_lint: CrateLint)
3361 -> Option<PathResolution> {
3363 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3364 ns={:?}, span={:?}, global_by_default={:?})",
3373 if let Some(qself) = qself {
3374 if qself.position == 0 {
3375 // This is a case like `<T>::B`, where there is no
3376 // trait to resolve. In that case, we leave the `B`
3377 // segment to be resolved by type-check.
3378 return Some(PathResolution::with_unresolved_segments(
3379 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3383 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3385 // Currently, `path` names the full item (`A::B::C`, in
3386 // our example). so we extract the prefix of that that is
3387 // the trait (the slice upto and including
3388 // `qself.position`). And then we recursively resolve that,
3389 // but with `qself` set to `None`.
3391 // However, setting `qself` to none (but not changing the
3392 // span) loses the information about where this path
3393 // *actually* appears, so for the purposes of the crate
3394 // lint we pass along information that this is the trait
3395 // name from a fully qualified path, and this also
3396 // contains the full span (the `CrateLint::QPathTrait`).
3397 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3398 let res = self.smart_resolve_path_fragment(
3401 &path[..qself.position + 1],
3403 PathSource::TraitItem(ns),
3404 CrateLint::QPathTrait {
3406 qpath_span: qself.path_span,
3410 // The remaining segments (the `C` in our example) will
3411 // have to be resolved by type-check, since that requires doing
3412 // trait resolution.
3413 return Some(PathResolution::with_unresolved_segments(
3414 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3418 let result = match self.resolve_path(
3426 PathResult::NonModule(path_res) => path_res,
3427 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3428 PathResolution::new(module.def().unwrap())
3430 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3431 // don't report an error right away, but try to fallback to a primitive type.
3432 // So, we are still able to successfully resolve something like
3434 // use std::u8; // bring module u8 in scope
3435 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3436 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3437 // // not to non-existent std::u8::max_value
3440 // Such behavior is required for backward compatibility.
3441 // The same fallback is used when `a` resolves to nothing.
3442 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3443 PathResult::Failed(..)
3444 if (ns == TypeNS || path.len() > 1) &&
3445 self.primitive_type_table.primitive_types
3446 .contains_key(&path[0].name) => {
3447 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3448 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3450 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3451 PathResolution::new(module.def().unwrap()),
3452 PathResult::Failed(span, msg, false) => {
3453 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3454 err_path_resolution()
3456 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3457 PathResult::Failed(..) => return None,
3458 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3461 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3462 path[0].name != keywords::CrateRoot.name() &&
3463 path[0].name != keywords::DollarCrate.name() {
3464 let unqualified_result = {
3465 match self.resolve_path(
3467 &[*path.last().unwrap()],
3473 PathResult::NonModule(path_res) => path_res.base_def(),
3474 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3475 module.def().unwrap(),
3476 _ => return Some(result),
3479 if result.base_def() == unqualified_result {
3480 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3481 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3490 base_module: Option<ModuleOrUniformRoot<'a>>,
3492 opt_ns: Option<Namespace>, // `None` indicates a module path
3495 crate_lint: CrateLint,
3496 ) -> PathResult<'a> {
3497 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3498 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3499 record_used, path_span, crate_lint)
3502 fn resolve_path_with_parent_scope(
3504 base_module: Option<ModuleOrUniformRoot<'a>>,
3506 opt_ns: Option<Namespace>, // `None` indicates a module path
3507 parent_scope: &ParentScope<'a>,
3510 crate_lint: CrateLint,
3511 ) -> PathResult<'a> {
3512 let mut module = base_module;
3513 let mut allow_super = true;
3514 let mut second_binding = None;
3515 self.current_module = parent_scope.module;
3518 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3519 path_span={:?}, crate_lint={:?})",
3527 for (i, &ident) in path.iter().enumerate() {
3528 debug!("resolve_path ident {} {:?}", i, ident);
3529 let is_last = i == path.len() - 1;
3530 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3531 let name = ident.name;
3533 allow_super &= ns == TypeNS &&
3534 (name == keywords::SelfValue.name() ||
3535 name == keywords::Super.name());
3538 if allow_super && name == keywords::Super.name() {
3539 let mut ctxt = ident.span.ctxt().modern();
3540 let self_module = match i {
3541 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3543 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3547 if let Some(self_module) = self_module {
3548 if let Some(parent) = self_module.parent {
3549 module = Some(ModuleOrUniformRoot::Module(
3550 self.resolve_self(&mut ctxt, parent)));
3554 let msg = "There are too many initial `super`s.".to_string();
3555 return PathResult::Failed(ident.span, msg, false);
3558 if name == keywords::SelfValue.name() {
3559 let mut ctxt = ident.span.ctxt().modern();
3560 module = Some(ModuleOrUniformRoot::Module(
3561 self.resolve_self(&mut ctxt, self.current_module)));
3564 if name == keywords::Extern.name() ||
3565 name == keywords::CrateRoot.name() &&
3566 self.session.features_untracked().extern_absolute_paths &&
3567 self.session.rust_2018() {
3568 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3571 if name == keywords::CrateRoot.name() ||
3572 name == keywords::Crate.name() ||
3573 name == keywords::DollarCrate.name() {
3574 // `::a::b`, `crate::a::b` or `$crate::a::b`
3575 module = Some(ModuleOrUniformRoot::Module(
3576 self.resolve_crate_root(ident)));
3582 // Report special messages for path segment keywords in wrong positions.
3583 if ident.is_path_segment_keyword() && i != 0 {
3584 let name_str = if name == keywords::CrateRoot.name() {
3585 "crate root".to_string()
3587 format!("`{}`", name)
3589 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3590 format!("global paths cannot start with {}", name_str)
3592 format!("{} in paths can only be used in start position", name_str)
3594 return PathResult::Failed(ident.span, msg, false);
3597 let binding = if let Some(module) = module {
3598 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3599 } else if opt_ns == Some(MacroNS) {
3600 assert!(ns == TypeNS);
3601 self.resolve_lexical_macro_path_segment(ident, ns, None, parent_scope, record_used,
3602 record_used, path_span).map(|(b, _)| b)
3604 let record_used_id =
3605 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3606 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3607 // we found a locally-imported or available item/module
3608 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3609 // we found a local variable or type param
3610 Some(LexicalScopeBinding::Def(def))
3611 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3612 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3616 _ => Err(if record_used { Determined } else { Undetermined }),
3623 second_binding = Some(binding);
3625 let def = binding.def();
3626 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3627 if let Some(next_module) = binding.module() {
3628 module = Some(ModuleOrUniformRoot::Module(next_module));
3629 } else if def == Def::ToolMod && i + 1 != path.len() {
3630 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3631 return PathResult::NonModule(PathResolution::new(def));
3632 } else if def == Def::Err {
3633 return PathResult::NonModule(err_path_resolution());
3634 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3635 self.lint_if_path_starts_with_module(
3641 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3642 def, path.len() - i - 1
3645 return PathResult::Failed(ident.span,
3646 format!("Not a module `{}`", ident),
3650 Err(Undetermined) => return PathResult::Indeterminate,
3651 Err(Determined) => {
3652 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3653 if opt_ns.is_some() && !module.is_normal() {
3654 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3655 module.def().unwrap(), path.len() - i
3659 let module_def = match module {
3660 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3663 let msg = if module_def == self.graph_root.def() {
3664 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3665 let mut candidates =
3666 self.lookup_import_candidates(name, TypeNS, is_mod);
3667 candidates.sort_by_cached_key(|c| {
3668 (c.path.segments.len(), c.path.to_string())
3670 if let Some(candidate) = candidates.get(0) {
3671 format!("Did you mean `{}`?", candidate.path)
3673 format!("Maybe a missing `extern crate {};`?", ident)
3676 format!("Use of undeclared type or module `{}`", ident)
3678 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3680 return PathResult::Failed(ident.span, msg, is_last);
3685 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3687 PathResult::Module(module.unwrap_or_else(|| {
3688 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3693 fn lint_if_path_starts_with_module(
3695 crate_lint: CrateLint,
3698 second_binding: Option<&NameBinding>,
3700 // In the 2018 edition this lint is a hard error, so nothing to do
3701 if self.session.rust_2018() {
3705 // In the 2015 edition there's no use in emitting lints unless the
3706 // crate's already enabled the feature that we're going to suggest
3707 if !self.session.features_untracked().crate_in_paths {
3711 let (diag_id, diag_span) = match crate_lint {
3712 CrateLint::No => return,
3713 CrateLint::SimplePath(id) => (id, path_span),
3714 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3715 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3718 let first_name = match path.get(0) {
3719 Some(ident) => ident.name,
3723 // We're only interested in `use` paths which should start with
3724 // `{{root}}` or `extern` currently.
3725 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3730 // If this import looks like `crate::...` it's already good
3731 Some(ident) if ident.name == keywords::Crate.name() => return,
3732 // Otherwise go below to see if it's an extern crate
3734 // If the path has length one (and it's `CrateRoot` most likely)
3735 // then we don't know whether we're gonna be importing a crate or an
3736 // item in our crate. Defer this lint to elsewhere
3740 // If the first element of our path was actually resolved to an
3741 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3742 // warning, this looks all good!
3743 if let Some(binding) = second_binding {
3744 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3745 // Careful: we still want to rewrite paths from
3746 // renamed extern crates.
3747 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3753 let diag = lint::builtin::BuiltinLintDiagnostics
3754 ::AbsPathWithModule(diag_span);
3755 self.session.buffer_lint_with_diagnostic(
3756 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3758 "absolute paths must start with `self`, `super`, \
3759 `crate`, or an external crate name in the 2018 edition",
3763 // Resolve a local definition, potentially adjusting for closures.
3764 fn adjust_local_def(&mut self,
3769 span: Span) -> Def {
3770 let ribs = &self.ribs[ns][rib_index + 1..];
3772 // An invalid forward use of a type parameter from a previous default.
3773 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3775 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3777 assert_eq!(def, Def::Err);
3783 span_bug!(span, "unexpected {:?} in bindings", def)
3785 Def::Local(node_id) => {
3788 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3789 ForwardTyParamBanRibKind => {
3790 // Nothing to do. Continue.
3792 ClosureRibKind(function_id) => {
3795 let seen = self.freevars_seen
3798 if let Some(&index) = seen.get(&node_id) {
3799 def = Def::Upvar(node_id, index, function_id);
3802 let vec = self.freevars
3805 let depth = vec.len();
3806 def = Def::Upvar(node_id, depth, function_id);
3813 seen.insert(node_id, depth);
3816 ItemRibKind | TraitOrImplItemRibKind => {
3817 // This was an attempt to access an upvar inside a
3818 // named function item. This is not allowed, so we
3821 resolve_error(self, span,
3822 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3826 ConstantItemRibKind => {
3827 // Still doesn't deal with upvars
3829 resolve_error(self, span,
3830 ResolutionError::AttemptToUseNonConstantValueInConstant);
3837 Def::TyParam(..) | Def::SelfTy(..) => {
3840 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3841 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3842 ConstantItemRibKind => {
3843 // Nothing to do. Continue.
3846 // This was an attempt to use a type parameter outside
3849 resolve_error(self, span,
3850 ResolutionError::TypeParametersFromOuterFunction(def));
3862 fn lookup_assoc_candidate<FilterFn>(&mut self,
3865 filter_fn: FilterFn)
3866 -> Option<AssocSuggestion>
3867 where FilterFn: Fn(Def) -> bool
3869 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3871 TyKind::Path(None, _) => Some(t.id),
3872 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3873 // This doesn't handle the remaining `Ty` variants as they are not
3874 // that commonly the self_type, it might be interesting to provide
3875 // support for those in future.
3880 // Fields are generally expected in the same contexts as locals.
3881 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3882 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3883 // Look for a field with the same name in the current self_type.
3884 if let Some(resolution) = self.def_map.get(&node_id) {
3885 match resolution.base_def() {
3886 Def::Struct(did) | Def::Union(did)
3887 if resolution.unresolved_segments() == 0 => {
3888 if let Some(field_names) = self.field_names.get(&did) {
3889 if field_names.iter().any(|&field_name| ident.name == field_name) {
3890 return Some(AssocSuggestion::Field);
3900 // Look for associated items in the current trait.
3901 if let Some((module, _)) = self.current_trait_ref {
3902 if let Ok(binding) = self.resolve_ident_in_module(
3903 ModuleOrUniformRoot::Module(module),
3909 let def = binding.def();
3911 return Some(if self.has_self.contains(&def.def_id()) {
3912 AssocSuggestion::MethodWithSelf
3914 AssocSuggestion::AssocItem
3923 fn lookup_typo_candidate<FilterFn>(&mut self,
3926 filter_fn: FilterFn,
3929 where FilterFn: Fn(Def) -> bool
3931 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3932 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3933 if let Some(binding) = resolution.borrow().binding {
3934 if filter_fn(binding.def()) {
3935 names.push(ident.name);
3941 let mut names = Vec::new();
3942 if path.len() == 1 {
3943 // Search in lexical scope.
3944 // Walk backwards up the ribs in scope and collect candidates.
3945 for rib in self.ribs[ns].iter().rev() {
3946 // Locals and type parameters
3947 for (ident, def) in &rib.bindings {
3948 if filter_fn(*def) {
3949 names.push(ident.name);
3953 if let ModuleRibKind(module) = rib.kind {
3954 // Items from this module
3955 add_module_candidates(module, &mut names);
3957 if let ModuleKind::Block(..) = module.kind {
3958 // We can see through blocks
3960 // Items from the prelude
3961 if !module.no_implicit_prelude {
3962 names.extend(self.extern_prelude.iter().cloned());
3963 if let Some(prelude) = self.prelude {
3964 add_module_candidates(prelude, &mut names);
3971 // Add primitive types to the mix
3972 if filter_fn(Def::PrimTy(Bool)) {
3974 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3978 // Search in module.
3979 let mod_path = &path[..path.len() - 1];
3980 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
3981 false, span, CrateLint::No) {
3982 if let ModuleOrUniformRoot::Module(module) = module {
3983 add_module_candidates(module, &mut names);
3988 let name = path[path.len() - 1].name;
3989 // Make sure error reporting is deterministic.
3990 names.sort_by_cached_key(|name| name.as_str());
3991 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3992 Some(found) if found != name => Some(found),
3997 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3998 where F: FnOnce(&mut Resolver)
4000 if let Some(label) = label {
4001 self.unused_labels.insert(id, label.ident.span);
4002 let def = Def::Label(id);
4003 self.with_label_rib(|this| {
4004 let ident = label.ident.modern_and_legacy();
4005 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4013 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4014 self.with_resolved_label(label, id, |this| this.visit_block(block));
4017 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4018 // First, record candidate traits for this expression if it could
4019 // result in the invocation of a method call.
4021 self.record_candidate_traits_for_expr_if_necessary(expr);
4023 // Next, resolve the node.
4025 ExprKind::Path(ref qself, ref path) => {
4026 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4027 visit::walk_expr(self, expr);
4030 ExprKind::Struct(ref path, ..) => {
4031 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4032 visit::walk_expr(self, expr);
4035 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4036 let def = self.search_label(label.ident, |rib, ident| {
4037 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4041 // Search again for close matches...
4042 // Picks the first label that is "close enough", which is not necessarily
4043 // the closest match
4044 let close_match = self.search_label(label.ident, |rib, ident| {
4045 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4046 find_best_match_for_name(names, &*ident.as_str(), None)
4048 self.record_def(expr.id, err_path_resolution());
4051 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4054 Some(Def::Label(id)) => {
4055 // Since this def is a label, it is never read.
4056 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4057 self.unused_labels.remove(&id);
4060 span_bug!(expr.span, "label wasn't mapped to a label def!");
4064 // visit `break` argument if any
4065 visit::walk_expr(self, expr);
4068 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4069 self.visit_expr(subexpression);
4071 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4072 let mut bindings_list = FxHashMap();
4074 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4076 // This has to happen *after* we determine which pat_idents are variants
4077 self.check_consistent_bindings(pats);
4078 self.visit_block(if_block);
4079 self.ribs[ValueNS].pop();
4081 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4084 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4086 ExprKind::While(ref subexpression, ref block, label) => {
4087 self.with_resolved_label(label, expr.id, |this| {
4088 this.visit_expr(subexpression);
4089 this.visit_block(block);
4093 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4094 self.with_resolved_label(label, expr.id, |this| {
4095 this.visit_expr(subexpression);
4096 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4097 let mut bindings_list = FxHashMap();
4099 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4101 // This has to happen *after* we determine which pat_idents are variants
4102 this.check_consistent_bindings(pats);
4103 this.visit_block(block);
4104 this.ribs[ValueNS].pop();
4108 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4109 self.visit_expr(subexpression);
4110 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4111 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4113 self.resolve_labeled_block(label, expr.id, block);
4115 self.ribs[ValueNS].pop();
4118 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4120 // Equivalent to `visit::walk_expr` + passing some context to children.
4121 ExprKind::Field(ref subexpression, _) => {
4122 self.resolve_expr(subexpression, Some(expr));
4124 ExprKind::MethodCall(ref segment, ref arguments) => {
4125 let mut arguments = arguments.iter();
4126 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4127 for argument in arguments {
4128 self.resolve_expr(argument, None);
4130 self.visit_path_segment(expr.span, segment);
4133 ExprKind::Call(ref callee, ref arguments) => {
4134 self.resolve_expr(callee, Some(expr));
4135 for argument in arguments {
4136 self.resolve_expr(argument, None);
4139 ExprKind::Type(ref type_expr, _) => {
4140 self.current_type_ascription.push(type_expr.span);
4141 visit::walk_expr(self, expr);
4142 self.current_type_ascription.pop();
4144 // Resolve the body of async exprs inside the async closure to which they desugar
4145 ExprKind::Async(_, async_closure_id, ref block) => {
4146 let rib_kind = ClosureRibKind(async_closure_id);
4147 self.ribs[ValueNS].push(Rib::new(rib_kind));
4148 self.label_ribs.push(Rib::new(rib_kind));
4149 self.visit_block(&block);
4150 self.label_ribs.pop();
4151 self.ribs[ValueNS].pop();
4153 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4154 // resolve the arguments within the proper scopes so that usages of them inside the
4155 // closure are detected as upvars rather than normal closure arg usages.
4157 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4158 ref fn_decl, ref body, _span,
4160 let rib_kind = ClosureRibKind(expr.id);
4161 self.ribs[ValueNS].push(Rib::new(rib_kind));
4162 self.label_ribs.push(Rib::new(rib_kind));
4163 // Resolve arguments:
4164 let mut bindings_list = FxHashMap();
4165 for argument in &fn_decl.inputs {
4166 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4167 self.visit_ty(&argument.ty);
4169 // No need to resolve return type-- the outer closure return type is
4170 // FunctionRetTy::Default
4172 // Now resolve the inner closure
4174 let rib_kind = ClosureRibKind(inner_closure_id);
4175 self.ribs[ValueNS].push(Rib::new(rib_kind));
4176 self.label_ribs.push(Rib::new(rib_kind));
4177 // No need to resolve arguments: the inner closure has none.
4178 // Resolve the return type:
4179 visit::walk_fn_ret_ty(self, &fn_decl.output);
4181 self.visit_expr(body);
4182 self.label_ribs.pop();
4183 self.ribs[ValueNS].pop();
4185 self.label_ribs.pop();
4186 self.ribs[ValueNS].pop();
4189 visit::walk_expr(self, expr);
4194 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4196 ExprKind::Field(_, ident) => {
4197 // FIXME(#6890): Even though you can't treat a method like a
4198 // field, we need to add any trait methods we find that match
4199 // the field name so that we can do some nice error reporting
4200 // later on in typeck.
4201 let traits = self.get_traits_containing_item(ident, ValueNS);
4202 self.trait_map.insert(expr.id, traits);
4204 ExprKind::MethodCall(ref segment, ..) => {
4205 debug!("(recording candidate traits for expr) recording traits for {}",
4207 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4208 self.trait_map.insert(expr.id, traits);
4216 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4217 -> Vec<TraitCandidate> {
4218 debug!("(getting traits containing item) looking for '{}'", ident.name);
4220 let mut found_traits = Vec::new();
4221 // Look for the current trait.
4222 if let Some((module, _)) = self.current_trait_ref {
4223 if self.resolve_ident_in_module(
4224 ModuleOrUniformRoot::Module(module),
4230 let def_id = module.def_id().unwrap();
4231 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4235 ident.span = ident.span.modern();
4236 let mut search_module = self.current_module;
4238 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4239 search_module = unwrap_or!(
4240 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4244 if let Some(prelude) = self.prelude {
4245 if !search_module.no_implicit_prelude {
4246 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4253 fn get_traits_in_module_containing_item(&mut self,
4257 found_traits: &mut Vec<TraitCandidate>) {
4258 assert!(ns == TypeNS || ns == ValueNS);
4259 let mut traits = module.traits.borrow_mut();
4260 if traits.is_none() {
4261 let mut collected_traits = Vec::new();
4262 module.for_each_child(|name, ns, binding| {
4263 if ns != TypeNS { return }
4264 if let Def::Trait(_) = binding.def() {
4265 collected_traits.push((name, binding));
4268 *traits = Some(collected_traits.into_boxed_slice());
4271 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4272 let module = binding.module().unwrap();
4273 let mut ident = ident;
4274 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4277 if self.resolve_ident_in_module_unadjusted(
4278 ModuleOrUniformRoot::Module(module),
4285 let import_id = match binding.kind {
4286 NameBindingKind::Import { directive, .. } => {
4287 self.maybe_unused_trait_imports.insert(directive.id);
4288 self.add_to_glob_map(directive.id, trait_name);
4293 let trait_def_id = module.def_id().unwrap();
4294 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4299 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4301 namespace: Namespace,
4302 start_module: &'a ModuleData<'a>,
4304 filter_fn: FilterFn)
4305 -> Vec<ImportSuggestion>
4306 where FilterFn: Fn(Def) -> bool
4308 let mut candidates = Vec::new();
4309 let mut worklist = Vec::new();
4310 let mut seen_modules = FxHashSet();
4311 let not_local_module = crate_name != keywords::Crate.ident();
4312 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4314 while let Some((in_module,
4316 in_module_is_extern)) = worklist.pop() {
4317 self.populate_module_if_necessary(in_module);
4319 // We have to visit module children in deterministic order to avoid
4320 // instabilities in reported imports (#43552).
4321 in_module.for_each_child_stable(|ident, ns, name_binding| {
4322 // avoid imports entirely
4323 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4324 // avoid non-importable candidates as well
4325 if !name_binding.is_importable() { return; }
4327 // collect results based on the filter function
4328 if ident.name == lookup_name && ns == namespace {
4329 if filter_fn(name_binding.def()) {
4331 let mut segms = path_segments.clone();
4332 if self.session.rust_2018() {
4333 // crate-local absolute paths start with `crate::` in edition 2018
4334 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4336 0, ast::PathSegment::from_ident(crate_name)
4340 segms.push(ast::PathSegment::from_ident(ident));
4342 span: name_binding.span,
4345 // the entity is accessible in the following cases:
4346 // 1. if it's defined in the same crate, it's always
4347 // accessible (since private entities can be made public)
4348 // 2. if it's defined in another crate, it's accessible
4349 // only if both the module is public and the entity is
4350 // declared as public (due to pruning, we don't explore
4351 // outside crate private modules => no need to check this)
4352 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4353 candidates.push(ImportSuggestion { path: path });
4358 // collect submodules to explore
4359 if let Some(module) = name_binding.module() {
4361 let mut path_segments = path_segments.clone();
4362 path_segments.push(ast::PathSegment::from_ident(ident));
4364 let is_extern_crate_that_also_appears_in_prelude =
4365 name_binding.is_extern_crate() &&
4366 self.session.rust_2018();
4368 let is_visible_to_user =
4369 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4371 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4372 // add the module to the lookup
4373 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4374 if seen_modules.insert(module.def_id().unwrap()) {
4375 worklist.push((module, path_segments, is_extern));
4385 /// When name resolution fails, this method can be used to look up candidate
4386 /// entities with the expected name. It allows filtering them using the
4387 /// supplied predicate (which should be used to only accept the types of
4388 /// definitions expected e.g. traits). The lookup spans across all crates.
4390 /// NOTE: The method does not look into imports, but this is not a problem,
4391 /// since we report the definitions (thus, the de-aliased imports).
4392 fn lookup_import_candidates<FilterFn>(&mut self,
4394 namespace: Namespace,
4395 filter_fn: FilterFn)
4396 -> Vec<ImportSuggestion>
4397 where FilterFn: Fn(Def) -> bool
4399 let mut suggestions = vec![];
4402 self.lookup_import_candidates_from_module(
4403 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4407 if self.session.features_untracked().extern_prelude {
4408 let extern_prelude_names = self.extern_prelude.clone();
4409 for &krate_name in extern_prelude_names.iter() {
4410 let krate_ident = Ident::with_empty_ctxt(krate_name);
4411 let external_prelude_module = self.load_extern_prelude_crate_if_needed(krate_ident);
4414 self.lookup_import_candidates_from_module(
4415 lookup_name, namespace, external_prelude_module, krate_ident, &filter_fn
4424 fn find_module(&mut self,
4426 -> Option<(Module<'a>, ImportSuggestion)>
4428 let mut result = None;
4429 let mut worklist = Vec::new();
4430 let mut seen_modules = FxHashSet();
4431 worklist.push((self.graph_root, Vec::new()));
4433 while let Some((in_module, path_segments)) = worklist.pop() {
4434 // abort if the module is already found
4435 if result.is_some() { break; }
4437 self.populate_module_if_necessary(in_module);
4439 in_module.for_each_child_stable(|ident, _, name_binding| {
4440 // abort if the module is already found or if name_binding is private external
4441 if result.is_some() || !name_binding.vis.is_visible_locally() {
4444 if let Some(module) = name_binding.module() {
4446 let mut path_segments = path_segments.clone();
4447 path_segments.push(ast::PathSegment::from_ident(ident));
4448 if module.def() == Some(module_def) {
4450 span: name_binding.span,
4451 segments: path_segments,
4453 result = Some((module, ImportSuggestion { path: path }));
4455 // add the module to the lookup
4456 if seen_modules.insert(module.def_id().unwrap()) {
4457 worklist.push((module, path_segments));
4467 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4468 if let Def::Enum(..) = enum_def {} else {
4469 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4472 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4473 self.populate_module_if_necessary(enum_module);
4475 let mut variants = Vec::new();
4476 enum_module.for_each_child_stable(|ident, _, name_binding| {
4477 if let Def::Variant(..) = name_binding.def() {
4478 let mut segms = enum_import_suggestion.path.segments.clone();
4479 segms.push(ast::PathSegment::from_ident(ident));
4480 variants.push(Path {
4481 span: name_binding.span,
4490 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4491 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4492 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4493 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4497 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4499 ast::VisibilityKind::Public => ty::Visibility::Public,
4500 ast::VisibilityKind::Crate(..) => {
4501 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4503 ast::VisibilityKind::Inherited => {
4504 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4506 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4507 // Visibilities are resolved as global by default, add starting root segment.
4508 let segments = path.make_root().iter().chain(path.segments.iter())
4509 .map(|seg| seg.ident)
4510 .collect::<Vec<_>>();
4511 let def = self.smart_resolve_path_fragment(
4516 PathSource::Visibility,
4517 CrateLint::SimplePath(id),
4519 if def == Def::Err {
4520 ty::Visibility::Public
4522 let vis = ty::Visibility::Restricted(def.def_id());
4523 if self.is_accessible(vis) {
4526 self.session.span_err(path.span, "visibilities can only be restricted \
4527 to ancestor modules");
4528 ty::Visibility::Public
4535 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4536 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4539 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4540 vis.is_accessible_from(module.normal_ancestor_id, self)
4543 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4544 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4546 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4548 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4549 let note = if b1.expansion != Mark::root() {
4550 Some(if let Def::Macro(..) = b1.def() {
4551 format!("macro-expanded {} do not shadow",
4552 if b1.is_import() { "macro imports" } else { "macros" })
4554 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4555 if b1.is_import() { "imports" } else { "items" })
4557 } else if b1.is_glob_import() {
4558 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4563 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4564 err.span_label(ident.span, "ambiguous name");
4565 err.span_note(b1.span, &msg1);
4567 Def::Macro(..) if b2.span.is_dummy() =>
4568 err.note(&format!("`{}` is also a builtin macro", ident)),
4569 _ => err.span_note(b2.span, &msg2),
4571 if let Some(note) = note {
4577 fn report_errors(&mut self, krate: &Crate) {
4578 self.report_with_use_injections(krate);
4579 self.report_proc_macro_import(krate);
4580 let mut reported_spans = FxHashSet();
4582 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4583 let msg = "macro-expanded `macro_export` macros from the current crate \
4584 cannot be referred to by absolute paths";
4585 self.session.buffer_lint_with_diagnostic(
4586 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4587 CRATE_NODE_ID, span_use, msg,
4588 lint::builtin::BuiltinLintDiagnostics::
4589 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4593 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4594 if reported_spans.insert(ident.span) {
4595 self.report_ambiguity_error(ident, b1, b2);
4599 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4600 if !reported_spans.insert(span) { continue }
4601 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4605 fn report_with_use_injections(&mut self, krate: &Crate) {
4606 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4607 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4608 if !candidates.is_empty() {
4609 show_candidates(&mut err, span, &candidates, better, found_use);
4615 fn report_conflict<'b>(&mut self,
4619 new_binding: &NameBinding<'b>,
4620 old_binding: &NameBinding<'b>) {
4621 // Error on the second of two conflicting names
4622 if old_binding.span.lo() > new_binding.span.lo() {
4623 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4626 let container = match parent.kind {
4627 ModuleKind::Def(Def::Mod(_), _) => "module",
4628 ModuleKind::Def(Def::Trait(_), _) => "trait",
4629 ModuleKind::Block(..) => "block",
4633 let old_noun = match old_binding.is_import() {
4635 false => "definition",
4638 let new_participle = match new_binding.is_import() {
4643 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4645 if let Some(s) = self.name_already_seen.get(&name) {
4651 let old_kind = match (ns, old_binding.module()) {
4652 (ValueNS, _) => "value",
4653 (MacroNS, _) => "macro",
4654 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4655 (TypeNS, Some(module)) if module.is_normal() => "module",
4656 (TypeNS, Some(module)) if module.is_trait() => "trait",
4657 (TypeNS, _) => "type",
4660 let msg = format!("the name `{}` is defined multiple times", name);
4662 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4663 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4664 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4665 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4666 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4668 _ => match (old_binding.is_import(), new_binding.is_import()) {
4669 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4670 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4671 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4675 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4680 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4681 if !old_binding.span.is_dummy() {
4682 err.span_label(self.session.source_map().def_span(old_binding.span),
4683 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4686 // See https://github.com/rust-lang/rust/issues/32354
4687 if old_binding.is_import() || new_binding.is_import() {
4688 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4694 let cm = self.session.source_map();
4695 let rename_msg = "You can use `as` to change the binding name of the import";
4697 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4698 binding.is_renamed_extern_crate()) {
4699 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4700 format!("Other{}", name)
4702 format!("other_{}", name)
4705 err.span_suggestion_with_applicability(
4708 if snippet.ends_with(';') {
4709 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4711 format!("{} as {}", snippet, suggested_name)
4713 Applicability::MachineApplicable,
4716 err.span_label(binding.span, rename_msg);
4721 self.name_already_seen.insert(name, span);
4725 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4726 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4729 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4730 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4733 fn names_to_string(idents: &[Ident]) -> String {
4734 let mut result = String::new();
4735 for (i, ident) in idents.iter()
4736 .filter(|ident| ident.name != keywords::CrateRoot.name())
4739 result.push_str("::");
4741 result.push_str(&ident.as_str());
4746 fn path_names_to_string(path: &Path) -> String {
4747 names_to_string(&path.segments.iter()
4748 .map(|seg| seg.ident)
4749 .collect::<Vec<_>>())
4752 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4753 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4754 let variant_path = &suggestion.path;
4755 let variant_path_string = path_names_to_string(variant_path);
4757 let path_len = suggestion.path.segments.len();
4758 let enum_path = ast::Path {
4759 span: suggestion.path.span,
4760 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4762 let enum_path_string = path_names_to_string(&enum_path);
4764 (suggestion.path.span, variant_path_string, enum_path_string)
4768 /// When an entity with a given name is not available in scope, we search for
4769 /// entities with that name in all crates. This method allows outputting the
4770 /// results of this search in a programmer-friendly way
4771 fn show_candidates(err: &mut DiagnosticBuilder,
4772 // This is `None` if all placement locations are inside expansions
4774 candidates: &[ImportSuggestion],
4778 // we want consistent results across executions, but candidates are produced
4779 // by iterating through a hash map, so make sure they are ordered:
4780 let mut path_strings: Vec<_> =
4781 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4782 path_strings.sort();
4784 let better = if better { "better " } else { "" };
4785 let msg_diff = match path_strings.len() {
4786 1 => " is found in another module, you can import it",
4787 _ => "s are found in other modules, you can import them",
4789 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4791 if let Some(span) = span {
4792 for candidate in &mut path_strings {
4793 // produce an additional newline to separate the new use statement
4794 // from the directly following item.
4795 let additional_newline = if found_use {
4800 *candidate = format!("use {};\n{}", candidate, additional_newline);
4803 err.span_suggestions(span, &msg, path_strings);
4807 for candidate in path_strings {
4809 msg.push_str(&candidate);
4814 /// A somewhat inefficient routine to obtain the name of a module.
4815 fn module_to_string(module: Module) -> Option<String> {
4816 let mut names = Vec::new();
4818 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4819 if let ModuleKind::Def(_, name) = module.kind {
4820 if let Some(parent) = module.parent {
4821 names.push(Ident::with_empty_ctxt(name));
4822 collect_mod(names, parent);
4825 // danger, shouldn't be ident?
4826 names.push(Ident::from_str("<opaque>"));
4827 collect_mod(names, module.parent.unwrap());
4830 collect_mod(&mut names, module);
4832 if names.is_empty() {
4835 Some(names_to_string(&names.into_iter()
4837 .collect::<Vec<_>>()))
4840 fn err_path_resolution() -> PathResolution {
4841 PathResolution::new(Def::Err)
4844 #[derive(PartialEq,Copy, Clone)]
4845 pub enum MakeGlobMap {
4850 #[derive(Copy, Clone, Debug)]
4852 /// Do not issue the lint
4855 /// This lint applies to some random path like `impl ::foo::Bar`
4856 /// or whatever. In this case, we can take the span of that path.
4859 /// This lint comes from a `use` statement. In this case, what we
4860 /// care about really is the *root* `use` statement; e.g., if we
4861 /// have nested things like `use a::{b, c}`, we care about the
4863 UsePath { root_id: NodeId, root_span: Span },
4865 /// This is the "trait item" from a fully qualified path. For example,
4866 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4867 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4868 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4872 fn node_id(&self) -> Option<NodeId> {
4874 CrateLint::No => None,
4875 CrateLint::SimplePath(id) |
4876 CrateLint::UsePath { root_id: id, .. } |
4877 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4882 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }