1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
17 #![feature(rustc_diagnostic_macros)]
18 #![feature(slice_sort_by_cached_key)]
21 extern crate bitflags;
26 extern crate syntax_pos;
27 extern crate rustc_errors as errors;
31 extern crate rustc_data_structures;
32 extern crate rustc_metadata;
34 pub use rustc::hir::def::{Namespace, PerNS};
36 use self::TypeParameters::*;
39 use rustc::hir::map::{Definitions, DefCollector};
40 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
41 use rustc::middle::cstore::CrateStore;
42 use rustc::session::Session;
44 use rustc::hir::def::*;
45 use rustc::hir::def::Namespace::*;
46 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
47 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
48 use rustc::session::config::nightly_options;
50 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
52 use rustc_metadata::creader::CrateLoader;
53 use rustc_metadata::cstore::CStore;
55 use syntax::source_map::SourceMap;
56 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
57 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
58 use syntax::ext::base::SyntaxExtension;
59 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
60 use syntax::ext::base::MacroKind;
61 use syntax::symbol::{Symbol, keywords};
62 use syntax::util::lev_distance::find_best_match_for_name;
64 use syntax::visit::{self, FnKind, Visitor};
66 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
67 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
68 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
69 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
70 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
73 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
74 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
76 use std::cell::{Cell, RefCell};
77 use std::{cmp, fmt, iter, ptr};
78 use std::collections::BTreeSet;
79 use std::mem::replace;
80 use rustc_data_structures::ptr_key::PtrKey;
81 use rustc_data_structures::sync::Lrc;
83 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
84 use macros::{InvocationData, LegacyBinding, ParentScope};
86 // NB: This module needs to be declared first so diagnostics are
87 // registered before they are used.
92 mod build_reduced_graph;
95 fn is_known_tool(name: Name) -> bool {
96 ["clippy", "rustfmt"].contains(&&*name.as_str())
99 /// A free importable items suggested in case of resolution failure.
100 struct ImportSuggestion {
104 /// A field or associated item from self type suggested in case of resolution failure.
105 enum AssocSuggestion {
112 struct BindingError {
114 origin: BTreeSet<Span>,
115 target: BTreeSet<Span>,
118 impl PartialOrd for BindingError {
119 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
120 Some(self.cmp(other))
124 impl PartialEq for BindingError {
125 fn eq(&self, other: &BindingError) -> bool {
126 self.name == other.name
130 impl Ord for BindingError {
131 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
132 self.name.cmp(&other.name)
136 enum ResolutionError<'a> {
137 /// error E0401: can't use type parameters from outer function
138 TypeParametersFromOuterFunction(Def),
139 /// error E0403: the name is already used for a type parameter in this type parameter list
140 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
141 /// error E0407: method is not a member of trait
142 MethodNotMemberOfTrait(Name, &'a str),
143 /// error E0437: type is not a member of trait
144 TypeNotMemberOfTrait(Name, &'a str),
145 /// error E0438: const is not a member of trait
146 ConstNotMemberOfTrait(Name, &'a str),
147 /// error E0408: variable `{}` is not bound in all patterns
148 VariableNotBoundInPattern(&'a BindingError),
149 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
150 VariableBoundWithDifferentMode(Name, Span),
151 /// error E0415: identifier is bound more than once in this parameter list
152 IdentifierBoundMoreThanOnceInParameterList(&'a str),
153 /// error E0416: identifier is bound more than once in the same pattern
154 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
155 /// error E0426: use of undeclared label
156 UndeclaredLabel(&'a str, Option<Name>),
157 /// error E0429: `self` imports are only allowed within a { } list
158 SelfImportsOnlyAllowedWithin,
159 /// error E0430: `self` import can only appear once in the list
160 SelfImportCanOnlyAppearOnceInTheList,
161 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
162 SelfImportOnlyInImportListWithNonEmptyPrefix,
163 /// error E0433: failed to resolve
164 FailedToResolve(&'a str),
165 /// error E0434: can't capture dynamic environment in a fn item
166 CannotCaptureDynamicEnvironmentInFnItem,
167 /// error E0435: attempt to use a non-constant value in a constant
168 AttemptToUseNonConstantValueInConstant,
169 /// error E0530: X bindings cannot shadow Ys
170 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
171 /// error E0128: type parameters with a default cannot use forward declared identifiers
172 ForwardDeclaredTyParam,
175 /// Combines an error with provided span and emits it
177 /// This takes the error provided, combines it with the span and any additional spans inside the
178 /// error and emits it.
179 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
181 resolution_error: ResolutionError<'a>) {
182 resolve_struct_error(resolver, span, resolution_error).emit();
185 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
187 resolution_error: ResolutionError<'a>)
188 -> DiagnosticBuilder<'sess> {
189 match resolution_error {
190 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
191 let mut err = struct_span_err!(resolver.session,
194 "can't use type parameters from outer function");
195 err.span_label(span, "use of type variable from outer function");
197 let cm = resolver.session.source_map();
199 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
200 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
201 resolver.definitions.opt_span(def_id)
204 reduce_impl_span_to_impl_keyword(cm, impl_span),
205 "`Self` type implicitly declared here, by this `impl`",
208 match (maybe_trait_defid, maybe_impl_defid) {
210 err.span_label(span, "can't use `Self` here");
213 err.span_label(span, "use a type here instead");
215 (None, None) => bug!("`impl` without trait nor type?"),
219 Def::TyParam(typaram_defid) => {
220 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
221 err.span_label(typaram_span, "type variable from outer function");
225 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
230 // Try to retrieve the span of the function signature and generate a new message with
231 // a local type parameter
232 let sugg_msg = "try using a local type parameter instead";
233 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
234 // Suggest the modification to the user
235 err.span_suggestion_with_applicability(
239 Applicability::MachineApplicable,
241 } else if let Some(sp) = cm.generate_fn_name_span(span) {
242 err.span_label(sp, "try adding a local type parameter in this method instead");
244 err.help("try using a local type parameter instead");
249 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
250 let mut err = struct_span_err!(resolver.session,
253 "the name `{}` is already used for a type parameter \
254 in this type parameter list",
256 err.span_label(span, "already used");
257 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
260 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
261 let mut err = struct_span_err!(resolver.session,
264 "method `{}` is not a member of trait `{}`",
267 err.span_label(span, format!("not a member of trait `{}`", trait_));
270 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
271 let mut err = struct_span_err!(resolver.session,
274 "type `{}` is not a member of trait `{}`",
277 err.span_label(span, format!("not a member of trait `{}`", trait_));
280 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
281 let mut err = struct_span_err!(resolver.session,
284 "const `{}` is not a member of trait `{}`",
287 err.span_label(span, format!("not a member of trait `{}`", trait_));
290 ResolutionError::VariableNotBoundInPattern(binding_error) => {
291 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
292 let msp = MultiSpan::from_spans(target_sp.clone());
293 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
294 let mut err = resolver.session.struct_span_err_with_code(
297 DiagnosticId::Error("E0408".into()),
299 for sp in target_sp {
300 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
302 let origin_sp = binding_error.origin.iter().cloned();
303 for sp in origin_sp {
304 err.span_label(sp, "variable not in all patterns");
308 ResolutionError::VariableBoundWithDifferentMode(variable_name,
309 first_binding_span) => {
310 let mut err = struct_span_err!(resolver.session,
313 "variable `{}` is bound in inconsistent \
314 ways within the same match arm",
316 err.span_label(span, "bound in different ways");
317 err.span_label(first_binding_span, "first binding");
320 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
321 let mut err = struct_span_err!(resolver.session,
324 "identifier `{}` is bound more than once in this parameter list",
326 err.span_label(span, "used as parameter more than once");
329 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
330 let mut err = struct_span_err!(resolver.session,
333 "identifier `{}` is bound more than once in the same pattern",
335 err.span_label(span, "used in a pattern more than once");
338 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
339 let mut err = struct_span_err!(resolver.session,
342 "use of undeclared label `{}`",
344 if let Some(lev_candidate) = lev_candidate {
345 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
347 err.span_label(span, format!("undeclared label `{}`", name));
351 ResolutionError::SelfImportsOnlyAllowedWithin => {
352 struct_span_err!(resolver.session,
356 "`self` imports are only allowed within a { } list")
358 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
359 let mut err = struct_span_err!(resolver.session, span, E0430,
360 "`self` import can only appear once in an import list");
361 err.span_label(span, "can only appear once in an import list");
364 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
365 let mut err = struct_span_err!(resolver.session, span, E0431,
366 "`self` import can only appear in an import list with \
367 a non-empty prefix");
368 err.span_label(span, "can only appear in an import list with a non-empty prefix");
371 ResolutionError::FailedToResolve(msg) => {
372 let mut err = struct_span_err!(resolver.session, span, E0433,
373 "failed to resolve. {}", msg);
374 err.span_label(span, msg);
377 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
378 let mut err = struct_span_err!(resolver.session,
382 "can't capture dynamic environment in a fn item");
383 err.help("use the `|| { ... }` closure form instead");
386 ResolutionError::AttemptToUseNonConstantValueInConstant => {
387 let mut err = struct_span_err!(resolver.session, span, E0435,
388 "attempt to use a non-constant value in a constant");
389 err.span_label(span, "non-constant value");
392 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
393 let shadows_what = PathResolution::new(binding.def()).kind_name();
394 let mut err = struct_span_err!(resolver.session,
397 "{}s cannot shadow {}s", what_binding, shadows_what);
398 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
399 let participle = if binding.is_import() { "imported" } else { "defined" };
400 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
401 err.span_label(binding.span, msg);
404 ResolutionError::ForwardDeclaredTyParam => {
405 let mut err = struct_span_err!(resolver.session, span, E0128,
406 "type parameters with a default cannot use \
407 forward declared identifiers");
409 span, "defaulted type parameters cannot be forward declared".to_string());
415 /// Adjust the impl span so that just the `impl` keyword is taken by removing
416 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
417 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
419 /// Attention: The method used is very fragile since it essentially duplicates the work of the
420 /// parser. If you need to use this function or something similar, please consider updating the
421 /// source_map functions and this function to something more robust.
422 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
423 let impl_span = cm.span_until_char(impl_span, '<');
424 let impl_span = cm.span_until_whitespace(impl_span);
428 #[derive(Copy, Clone, Debug)]
431 binding_mode: BindingMode,
434 /// Map from the name in a pattern to its binding mode.
435 type BindingMap = FxHashMap<Ident, BindingInfo>;
437 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
448 fn descr(self) -> &'static str {
450 PatternSource::Match => "match binding",
451 PatternSource::IfLet => "if let binding",
452 PatternSource::WhileLet => "while let binding",
453 PatternSource::Let => "let binding",
454 PatternSource::For => "for binding",
455 PatternSource::FnParam => "function parameter",
460 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
461 enum AliasPossibility {
466 #[derive(Copy, Clone, Debug)]
467 enum PathSource<'a> {
468 // Type paths `Path`.
470 // Trait paths in bounds or impls.
471 Trait(AliasPossibility),
472 // Expression paths `path`, with optional parent context.
473 Expr(Option<&'a Expr>),
474 // Paths in path patterns `Path`.
476 // Paths in struct expressions and patterns `Path { .. }`.
478 // Paths in tuple struct patterns `Path(..)`.
480 // `m::A::B` in `<T as m::A>::B::C`.
481 TraitItem(Namespace),
482 // Path in `pub(path)`
484 // Path in `use a::b::{...};`
488 impl<'a> PathSource<'a> {
489 fn namespace(self) -> Namespace {
491 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
492 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
493 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
494 PathSource::TraitItem(ns) => ns,
498 fn global_by_default(self) -> bool {
500 PathSource::Visibility | PathSource::ImportPrefix => true,
501 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
502 PathSource::Struct | PathSource::TupleStruct |
503 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
507 fn defer_to_typeck(self) -> bool {
509 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
510 PathSource::Struct | PathSource::TupleStruct => true,
511 PathSource::Trait(_) | PathSource::TraitItem(..) |
512 PathSource::Visibility | PathSource::ImportPrefix => false,
516 fn descr_expected(self) -> &'static str {
518 PathSource::Type => "type",
519 PathSource::Trait(_) => "trait",
520 PathSource::Pat => "unit struct/variant or constant",
521 PathSource::Struct => "struct, variant or union type",
522 PathSource::TupleStruct => "tuple struct/variant",
523 PathSource::Visibility => "module",
524 PathSource::ImportPrefix => "module or enum",
525 PathSource::TraitItem(ns) => match ns {
526 TypeNS => "associated type",
527 ValueNS => "method or associated constant",
528 MacroNS => bug!("associated macro"),
530 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
531 // "function" here means "anything callable" rather than `Def::Fn`,
532 // this is not precise but usually more helpful than just "value".
533 Some(&ExprKind::Call(..)) => "function",
539 fn is_expected(self, def: Def) -> bool {
541 PathSource::Type => match def {
542 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
543 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
544 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
545 Def::Existential(..) |
546 Def::ForeignTy(..) => true,
549 PathSource::Trait(AliasPossibility::No) => match def {
550 Def::Trait(..) => true,
553 PathSource::Trait(AliasPossibility::Maybe) => match def {
554 Def::Trait(..) => true,
555 Def::TraitAlias(..) => true,
558 PathSource::Expr(..) => match def {
559 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
560 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
561 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
562 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
563 Def::SelfCtor(..) => true,
566 PathSource::Pat => match def {
567 Def::StructCtor(_, CtorKind::Const) |
568 Def::VariantCtor(_, CtorKind::Const) |
569 Def::Const(..) | Def::AssociatedConst(..) |
570 Def::SelfCtor(..) => true,
573 PathSource::TupleStruct => match def {
574 Def::StructCtor(_, CtorKind::Fn) |
575 Def::VariantCtor(_, CtorKind::Fn) |
576 Def::SelfCtor(..) => true,
579 PathSource::Struct => match def {
580 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
581 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
584 PathSource::TraitItem(ns) => match def {
585 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
586 Def::AssociatedTy(..) if ns == TypeNS => true,
589 PathSource::ImportPrefix => match def {
590 Def::Mod(..) | Def::Enum(..) => true,
593 PathSource::Visibility => match def {
594 Def::Mod(..) => true,
600 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
601 __diagnostic_used!(E0404);
602 __diagnostic_used!(E0405);
603 __diagnostic_used!(E0412);
604 __diagnostic_used!(E0422);
605 __diagnostic_used!(E0423);
606 __diagnostic_used!(E0425);
607 __diagnostic_used!(E0531);
608 __diagnostic_used!(E0532);
609 __diagnostic_used!(E0573);
610 __diagnostic_used!(E0574);
611 __diagnostic_used!(E0575);
612 __diagnostic_used!(E0576);
613 __diagnostic_used!(E0577);
614 __diagnostic_used!(E0578);
615 match (self, has_unexpected_resolution) {
616 (PathSource::Trait(_), true) => "E0404",
617 (PathSource::Trait(_), false) => "E0405",
618 (PathSource::Type, true) => "E0573",
619 (PathSource::Type, false) => "E0412",
620 (PathSource::Struct, true) => "E0574",
621 (PathSource::Struct, false) => "E0422",
622 (PathSource::Expr(..), true) => "E0423",
623 (PathSource::Expr(..), false) => "E0425",
624 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
625 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
626 (PathSource::TraitItem(..), true) => "E0575",
627 (PathSource::TraitItem(..), false) => "E0576",
628 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
629 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
634 struct UsePlacementFinder {
635 target_module: NodeId,
640 impl UsePlacementFinder {
641 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
642 let mut finder = UsePlacementFinder {
647 visit::walk_crate(&mut finder, krate);
648 (finder.span, finder.found_use)
652 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
655 module: &'tcx ast::Mod,
657 _: &[ast::Attribute],
660 if self.span.is_some() {
663 if node_id != self.target_module {
664 visit::walk_mod(self, module);
667 // find a use statement
668 for item in &module.items {
670 ItemKind::Use(..) => {
671 // don't suggest placing a use before the prelude
672 // import or other generated ones
673 if item.span.ctxt().outer().expn_info().is_none() {
674 self.span = Some(item.span.shrink_to_lo());
675 self.found_use = true;
679 // don't place use before extern crate
680 ItemKind::ExternCrate(_) => {}
681 // but place them before the first other item
682 _ => if self.span.map_or(true, |span| item.span < span ) {
683 if item.span.ctxt().outer().expn_info().is_none() {
684 // don't insert between attributes and an item
685 if item.attrs.is_empty() {
686 self.span = Some(item.span.shrink_to_lo());
688 // find the first attribute on the item
689 for attr in &item.attrs {
690 if self.span.map_or(true, |span| attr.span < span) {
691 self.span = Some(attr.span.shrink_to_lo());
702 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
703 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
704 fn visit_item(&mut self, item: &'tcx Item) {
705 self.resolve_item(item);
707 fn visit_arm(&mut self, arm: &'tcx Arm) {
708 self.resolve_arm(arm);
710 fn visit_block(&mut self, block: &'tcx Block) {
711 self.resolve_block(block);
713 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
714 self.with_constant_rib(|this| {
715 visit::walk_anon_const(this, constant);
718 fn visit_expr(&mut self, expr: &'tcx Expr) {
719 self.resolve_expr(expr, None);
721 fn visit_local(&mut self, local: &'tcx Local) {
722 self.resolve_local(local);
724 fn visit_ty(&mut self, ty: &'tcx Ty) {
726 TyKind::Path(ref qself, ref path) => {
727 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
729 TyKind::ImplicitSelf => {
730 let self_ty = keywords::SelfType.ident();
731 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
732 .map_or(Def::Err, |d| d.def());
733 self.record_def(ty.id, PathResolution::new(def));
737 visit::walk_ty(self, ty);
739 fn visit_poly_trait_ref(&mut self,
740 tref: &'tcx ast::PolyTraitRef,
741 m: &'tcx ast::TraitBoundModifier) {
742 self.smart_resolve_path(tref.trait_ref.ref_id, None,
743 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
744 visit::walk_poly_trait_ref(self, tref, m);
746 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
747 let type_parameters = match foreign_item.node {
748 ForeignItemKind::Fn(_, ref generics) => {
749 HasTypeParameters(generics, ItemRibKind)
751 ForeignItemKind::Static(..) => NoTypeParameters,
752 ForeignItemKind::Ty => NoTypeParameters,
753 ForeignItemKind::Macro(..) => NoTypeParameters,
755 self.with_type_parameter_rib(type_parameters, |this| {
756 visit::walk_foreign_item(this, foreign_item);
759 fn visit_fn(&mut self,
760 function_kind: FnKind<'tcx>,
761 declaration: &'tcx FnDecl,
765 let (rib_kind, asyncness) = match function_kind {
766 FnKind::ItemFn(_, ref header, ..) =>
767 (ItemRibKind, header.asyncness),
768 FnKind::Method(_, ref sig, _, _) =>
769 (TraitOrImplItemRibKind, sig.header.asyncness),
770 FnKind::Closure(_) =>
771 // Async closures aren't resolved through `visit_fn`-- they're
772 // processed separately
773 (ClosureRibKind(node_id), IsAsync::NotAsync),
776 // Create a value rib for the function.
777 self.ribs[ValueNS].push(Rib::new(rib_kind));
779 // Create a label rib for the function.
780 self.label_ribs.push(Rib::new(rib_kind));
782 // Add each argument to the rib.
783 let mut bindings_list = FxHashMap::default();
784 for argument in &declaration.inputs {
785 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
787 self.visit_ty(&argument.ty);
789 debug!("(resolving function) recorded argument");
791 visit::walk_fn_ret_ty(self, &declaration.output);
793 // Resolve the function body, potentially inside the body of an async closure
794 if let IsAsync::Async { closure_id, .. } = asyncness {
795 let rib_kind = ClosureRibKind(closure_id);
796 self.ribs[ValueNS].push(Rib::new(rib_kind));
797 self.label_ribs.push(Rib::new(rib_kind));
800 match function_kind {
801 FnKind::ItemFn(.., body) |
802 FnKind::Method(.., body) => {
803 self.visit_block(body);
805 FnKind::Closure(body) => {
806 self.visit_expr(body);
810 // Leave the body of the async closure
811 if asyncness.is_async() {
812 self.label_ribs.pop();
813 self.ribs[ValueNS].pop();
816 debug!("(resolving function) leaving function");
818 self.label_ribs.pop();
819 self.ribs[ValueNS].pop();
821 fn visit_generics(&mut self, generics: &'tcx Generics) {
822 // For type parameter defaults, we have to ban access
823 // to following type parameters, as the Substs can only
824 // provide previous type parameters as they're built. We
825 // put all the parameters on the ban list and then remove
826 // them one by one as they are processed and become available.
827 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
828 let mut found_default = false;
829 default_ban_rib.bindings.extend(generics.params.iter()
830 .filter_map(|param| match param.kind {
831 GenericParamKind::Lifetime { .. } => None,
832 GenericParamKind::Type { ref default, .. } => {
833 found_default |= default.is_some();
835 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
842 for param in &generics.params {
844 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
845 GenericParamKind::Type { ref default, .. } => {
846 for bound in ¶m.bounds {
847 self.visit_param_bound(bound);
850 if let Some(ref ty) = default {
851 self.ribs[TypeNS].push(default_ban_rib);
853 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
856 // Allow all following defaults to refer to this type parameter.
857 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
861 for p in &generics.where_clause.predicates {
862 self.visit_where_predicate(p);
867 #[derive(Copy, Clone)]
868 enum TypeParameters<'a, 'b> {
870 HasTypeParameters(// Type parameters.
873 // The kind of the rib used for type parameters.
877 /// The rib kind controls the translation of local
878 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
879 #[derive(Copy, Clone, Debug)]
881 /// No translation needs to be applied.
884 /// We passed through a closure scope at the given node ID.
885 /// Translate upvars as appropriate.
886 ClosureRibKind(NodeId /* func id */),
888 /// We passed through an impl or trait and are now in one of its
889 /// methods or associated types. Allow references to ty params that impl or trait
890 /// binds. Disallow any other upvars (including other ty params that are
892 TraitOrImplItemRibKind,
894 /// We passed through an item scope. Disallow upvars.
897 /// We're in a constant item. Can't refer to dynamic stuff.
900 /// We passed through a module.
901 ModuleRibKind(Module<'a>),
903 /// We passed through a `macro_rules!` statement
904 MacroDefinition(DefId),
906 /// All bindings in this rib are type parameters that can't be used
907 /// from the default of a type parameter because they're not declared
908 /// before said type parameter. Also see the `visit_generics` override.
909 ForwardTyParamBanRibKind,
914 /// A rib represents a scope names can live in. Note that these appear in many places, not just
915 /// around braces. At any place where the list of accessible names (of the given namespace)
916 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
917 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
920 /// Different [rib kinds](enum.RibKind) are transparent for different names.
922 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
923 /// resolving, the name is looked up from inside out.
926 bindings: FxHashMap<Ident, Def>,
931 fn new(kind: RibKind<'a>) -> Rib<'a> {
933 bindings: Default::default(),
939 /// An intermediate resolution result.
941 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
942 /// items are visible in their whole block, while defs only from the place they are defined
944 enum LexicalScopeBinding<'a> {
945 Item(&'a NameBinding<'a>),
949 impl<'a> LexicalScopeBinding<'a> {
950 fn item(self) -> Option<&'a NameBinding<'a>> {
952 LexicalScopeBinding::Item(binding) => Some(binding),
957 fn def(self) -> Def {
959 LexicalScopeBinding::Item(binding) => binding.def(),
960 LexicalScopeBinding::Def(def) => def,
965 #[derive(Copy, Clone, Debug)]
966 pub enum ModuleOrUniformRoot<'a> {
970 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
971 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
972 /// but *not* `extern`), in the Rust 2018 edition.
976 #[derive(Clone, Debug)]
977 enum PathResult<'a> {
978 Module(ModuleOrUniformRoot<'a>),
979 NonModule(PathResolution),
981 Failed(Span, String, bool /* is the error from the last segment? */),
985 /// An anonymous module, eg. just a block.
990 /// { // This is an anonymous module
991 /// f(); // This resolves to (2) as we are inside the block.
994 /// f(); // Resolves to (1)
998 /// Any module with a name.
1002 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1003 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1008 /// One node in the tree of modules.
1009 pub struct ModuleData<'a> {
1010 parent: Option<Module<'a>>,
1013 // The def id of the closest normal module (`mod`) ancestor (including this module).
1014 normal_ancestor_id: DefId,
1016 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1017 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1018 Option<&'a NameBinding<'a>>)>>,
1019 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1020 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1022 // Macro invocations that can expand into items in this module.
1023 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1025 no_implicit_prelude: bool,
1027 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1028 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1030 // Used to memoize the traits in this module for faster searches through all traits in scope.
1031 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1033 // Whether this module is populated. If not populated, any attempt to
1034 // access the children must be preceded with a
1035 // `populate_module_if_necessary` call.
1036 populated: Cell<bool>,
1038 /// Span of the module itself. Used for error reporting.
1044 type Module<'a> = &'a ModuleData<'a>;
1046 impl<'a> ModuleData<'a> {
1047 fn new(parent: Option<Module<'a>>,
1049 normal_ancestor_id: DefId,
1051 span: Span) -> Self {
1056 resolutions: Default::default(),
1057 legacy_macro_resolutions: RefCell::new(Vec::new()),
1058 macro_resolutions: RefCell::new(Vec::new()),
1059 builtin_attrs: RefCell::new(Vec::new()),
1060 unresolved_invocations: Default::default(),
1061 no_implicit_prelude: false,
1062 glob_importers: RefCell::new(Vec::new()),
1063 globs: RefCell::new(Vec::new()),
1064 traits: RefCell::new(None),
1065 populated: Cell::new(normal_ancestor_id.is_local()),
1071 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1072 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1073 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1077 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1078 let resolutions = self.resolutions.borrow();
1079 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1080 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1081 for &(&(ident, ns), &resolution) in resolutions.iter() {
1082 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1086 fn def(&self) -> Option<Def> {
1088 ModuleKind::Def(def, _) => Some(def),
1093 fn def_id(&self) -> Option<DefId> {
1094 self.def().as_ref().map(Def::def_id)
1097 // `self` resolves to the first module ancestor that `is_normal`.
1098 fn is_normal(&self) -> bool {
1100 ModuleKind::Def(Def::Mod(_), _) => true,
1105 fn is_trait(&self) -> bool {
1107 ModuleKind::Def(Def::Trait(_), _) => true,
1112 fn is_local(&self) -> bool {
1113 self.normal_ancestor_id.is_local()
1116 fn nearest_item_scope(&'a self) -> Module<'a> {
1117 if self.is_trait() { self.parent.unwrap() } else { self }
1120 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1121 while !ptr::eq(self, other) {
1122 if let Some(parent) = other.parent {
1132 impl<'a> fmt::Debug for ModuleData<'a> {
1133 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1134 write!(f, "{:?}", self.def())
1138 /// Records a possibly-private value, type, or module definition.
1139 #[derive(Clone, Debug)]
1140 pub struct NameBinding<'a> {
1141 kind: NameBindingKind<'a>,
1144 vis: ty::Visibility,
1147 pub trait ToNameBinding<'a> {
1148 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1151 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1152 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1157 #[derive(Clone, Debug)]
1158 enum NameBindingKind<'a> {
1159 Def(Def, /* is_macro_export */ bool),
1162 binding: &'a NameBinding<'a>,
1163 directive: &'a ImportDirective<'a>,
1167 b1: &'a NameBinding<'a>,
1168 b2: &'a NameBinding<'a>,
1172 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1174 struct UseError<'a> {
1175 err: DiagnosticBuilder<'a>,
1176 /// Attach `use` statements for these candidates
1177 candidates: Vec<ImportSuggestion>,
1178 /// The node id of the module to place the use statements in
1180 /// Whether the diagnostic should state that it's "better"
1184 struct AmbiguityError<'a> {
1186 b1: &'a NameBinding<'a>,
1187 b2: &'a NameBinding<'a>,
1190 impl<'a> NameBinding<'a> {
1191 fn module(&self) -> Option<Module<'a>> {
1193 NameBindingKind::Module(module) => Some(module),
1194 NameBindingKind::Import { binding, .. } => binding.module(),
1199 fn def(&self) -> Def {
1201 NameBindingKind::Def(def, _) => def,
1202 NameBindingKind::Module(module) => module.def().unwrap(),
1203 NameBindingKind::Import { binding, .. } => binding.def(),
1204 NameBindingKind::Ambiguity { .. } => Def::Err,
1208 fn def_ignoring_ambiguity(&self) -> Def {
1210 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1211 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1216 // We sometimes need to treat variants as `pub` for backwards compatibility
1217 fn pseudo_vis(&self) -> ty::Visibility {
1218 if self.is_variant() && self.def().def_id().is_local() {
1219 ty::Visibility::Public
1225 fn is_variant(&self) -> bool {
1227 NameBindingKind::Def(Def::Variant(..), _) |
1228 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1233 fn is_extern_crate(&self) -> bool {
1235 NameBindingKind::Import {
1236 directive: &ImportDirective {
1237 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1244 fn is_import(&self) -> bool {
1246 NameBindingKind::Import { .. } => true,
1251 fn is_renamed_extern_crate(&self) -> bool {
1252 if let NameBindingKind::Import { directive, ..} = self.kind {
1253 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1260 fn is_glob_import(&self) -> bool {
1262 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1263 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1268 fn is_importable(&self) -> bool {
1270 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1275 fn is_macro_def(&self) -> bool {
1277 NameBindingKind::Def(Def::Macro(..), _) => true,
1282 fn macro_kind(&self) -> Option<MacroKind> {
1283 match self.def_ignoring_ambiguity() {
1284 Def::Macro(_, kind) => Some(kind),
1285 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1290 fn descr(&self) -> &'static str {
1291 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1294 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1295 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1296 // Then this function returns `true` if `self` may emerge from a macro *after* that
1297 // in some later round and screw up our previously found resolution.
1298 // See more detailed explanation in
1299 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1300 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1301 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1302 // Expansions are partially ordered, so "may appear after" is an inversion of
1303 // "certainly appears before or simultaneously" and includes unordered cases.
1304 let self_parent_expansion = self.expansion;
1305 let other_parent_expansion = binding.expansion;
1306 let certainly_before_other_or_simultaneously =
1307 other_parent_expansion.is_descendant_of(self_parent_expansion);
1308 let certainly_before_invoc_or_simultaneously =
1309 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1310 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1314 /// Interns the names of the primitive types.
1316 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1317 /// special handling, since they have no place of origin.
1319 struct PrimitiveTypeTable {
1320 primitive_types: FxHashMap<Name, PrimTy>,
1323 impl PrimitiveTypeTable {
1324 fn new() -> PrimitiveTypeTable {
1325 let mut table = PrimitiveTypeTable::default();
1327 table.intern("bool", Bool);
1328 table.intern("char", Char);
1329 table.intern("f32", Float(FloatTy::F32));
1330 table.intern("f64", Float(FloatTy::F64));
1331 table.intern("isize", Int(IntTy::Isize));
1332 table.intern("i8", Int(IntTy::I8));
1333 table.intern("i16", Int(IntTy::I16));
1334 table.intern("i32", Int(IntTy::I32));
1335 table.intern("i64", Int(IntTy::I64));
1336 table.intern("i128", Int(IntTy::I128));
1337 table.intern("str", Str);
1338 table.intern("usize", Uint(UintTy::Usize));
1339 table.intern("u8", Uint(UintTy::U8));
1340 table.intern("u16", Uint(UintTy::U16));
1341 table.intern("u32", Uint(UintTy::U32));
1342 table.intern("u64", Uint(UintTy::U64));
1343 table.intern("u128", Uint(UintTy::U128));
1347 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1348 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1352 /// The main resolver class.
1354 /// This is the visitor that walks the whole crate.
1355 pub struct Resolver<'a, 'b: 'a> {
1356 session: &'a Session,
1359 pub definitions: Definitions,
1361 graph_root: Module<'a>,
1363 prelude: Option<Module<'a>>,
1364 pub extern_prelude: FxHashSet<Name>,
1366 /// n.b. This is used only for better diagnostics, not name resolution itself.
1367 has_self: FxHashSet<DefId>,
1369 /// Names of fields of an item `DefId` accessible with dot syntax.
1370 /// Used for hints during error reporting.
1371 field_names: FxHashMap<DefId, Vec<Name>>,
1373 /// All imports known to succeed or fail.
1374 determined_imports: Vec<&'a ImportDirective<'a>>,
1376 /// All non-determined imports.
1377 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1379 /// The module that represents the current item scope.
1380 current_module: Module<'a>,
1382 /// The current set of local scopes for types and values.
1383 /// FIXME #4948: Reuse ribs to avoid allocation.
1384 ribs: PerNS<Vec<Rib<'a>>>,
1386 /// The current set of local scopes, for labels.
1387 label_ribs: Vec<Rib<'a>>,
1389 /// The trait that the current context can refer to.
1390 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1392 /// The current self type if inside an impl (used for better errors).
1393 current_self_type: Option<Ty>,
1395 /// The current self item if inside an ADT (used for better errors).
1396 current_self_item: Option<NodeId>,
1398 /// The idents for the primitive types.
1399 primitive_type_table: PrimitiveTypeTable,
1402 import_map: ImportMap,
1403 pub freevars: FreevarMap,
1404 freevars_seen: NodeMap<NodeMap<usize>>,
1405 pub export_map: ExportMap,
1406 pub trait_map: TraitMap,
1408 /// A map from nodes to anonymous modules.
1409 /// Anonymous modules are pseudo-modules that are implicitly created around items
1410 /// contained within blocks.
1412 /// For example, if we have this:
1420 /// There will be an anonymous module created around `g` with the ID of the
1421 /// entry block for `f`.
1422 block_map: NodeMap<Module<'a>>,
1423 module_map: FxHashMap<DefId, Module<'a>>,
1424 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1425 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1427 pub make_glob_map: bool,
1428 /// Maps imports to the names of items actually imported (this actually maps
1429 /// all imports, but only glob imports are actually interesting).
1430 pub glob_map: GlobMap,
1432 used_imports: FxHashSet<(NodeId, Namespace)>,
1433 pub maybe_unused_trait_imports: NodeSet,
1434 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1436 /// A list of labels as of yet unused. Labels will be removed from this map when
1437 /// they are used (in a `break` or `continue` statement)
1438 pub unused_labels: FxHashMap<NodeId, Span>,
1440 /// privacy errors are delayed until the end in order to deduplicate them
1441 privacy_errors: Vec<PrivacyError<'a>>,
1442 /// ambiguity errors are delayed for deduplication
1443 ambiguity_errors: Vec<AmbiguityError<'a>>,
1444 /// `use` injections are delayed for better placement and deduplication
1445 use_injections: Vec<UseError<'a>>,
1446 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1447 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1449 arenas: &'a ResolverArenas<'a>,
1450 dummy_binding: &'a NameBinding<'a>,
1452 crate_loader: &'a mut CrateLoader<'b>,
1453 macro_names: FxHashSet<Ident>,
1454 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1455 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1456 pub all_macros: FxHashMap<Name, Def>,
1457 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1458 macro_defs: FxHashMap<Mark, DefId>,
1459 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1460 pub whitelisted_legacy_custom_derives: Vec<Name>,
1461 pub found_unresolved_macro: bool,
1463 /// List of crate local macros that we need to warn about as being unused.
1464 /// Right now this only includes macro_rules! macros, and macros 2.0.
1465 unused_macros: FxHashSet<DefId>,
1467 /// Maps the `Mark` of an expansion to its containing module or block.
1468 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1470 /// Avoid duplicated errors for "name already defined".
1471 name_already_seen: FxHashMap<Name, Span>,
1473 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1475 /// This table maps struct IDs into struct constructor IDs,
1476 /// it's not used during normal resolution, only for better error reporting.
1477 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1479 /// Only used for better errors on `fn(): fn()`
1480 current_type_ascription: Vec<Span>,
1482 injected_crate: Option<Module<'a>>,
1485 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1487 pub struct ResolverArenas<'a> {
1488 modules: arena::TypedArena<ModuleData<'a>>,
1489 local_modules: RefCell<Vec<Module<'a>>>,
1490 name_bindings: arena::TypedArena<NameBinding<'a>>,
1491 import_directives: arena::TypedArena<ImportDirective<'a>>,
1492 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1493 invocation_data: arena::TypedArena<InvocationData<'a>>,
1494 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1497 impl<'a> ResolverArenas<'a> {
1498 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1499 let module = self.modules.alloc(module);
1500 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1501 self.local_modules.borrow_mut().push(module);
1505 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1506 self.local_modules.borrow()
1508 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1509 self.name_bindings.alloc(name_binding)
1511 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1512 -> &'a ImportDirective {
1513 self.import_directives.alloc(import_directive)
1515 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1516 self.name_resolutions.alloc(Default::default())
1518 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1519 -> &'a InvocationData<'a> {
1520 self.invocation_data.alloc(expansion_data)
1522 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1523 self.legacy_bindings.alloc(binding)
1527 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1528 fn parent(self, id: DefId) -> Option<DefId> {
1530 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1531 _ => self.cstore.def_key(id).parent,
1532 }.map(|index| DefId { index, ..id })
1536 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1537 /// the resolver is no longer needed as all the relevant information is inline.
1538 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1539 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1540 self.resolve_hir_path_cb(path, is_value,
1541 |resolver, span, error| resolve_error(resolver, span, error))
1544 fn resolve_str_path(
1547 crate_root: Option<&str>,
1548 components: &[&str],
1549 args: Option<P<hir::GenericArgs>>,
1552 let mut segments = iter::once(keywords::CrateRoot.ident())
1554 crate_root.into_iter()
1555 .chain(components.iter().cloned())
1556 .map(Ident::from_str)
1557 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1559 if let Some(args) = args {
1560 let ident = segments.last().unwrap().ident;
1561 *segments.last_mut().unwrap() = hir::PathSegment {
1568 let mut path = hir::Path {
1571 segments: segments.into(),
1574 self.resolve_hir_path(&mut path, is_value);
1578 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1579 self.def_map.get(&id).cloned()
1582 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1583 self.import_map.get(&id).cloned().unwrap_or_default()
1586 fn definitions(&mut self) -> &mut Definitions {
1587 &mut self.definitions
1591 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1592 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1593 /// isn't something that can be returned because it can't be made to live that long,
1594 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1595 /// just that an error occurred.
1596 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1597 -> Result<hir::Path, ()> {
1599 let mut errored = false;
1601 let mut path = if path_str.starts_with("::") {
1605 segments: iter::once(keywords::CrateRoot.ident()).chain({
1606 path_str.split("::").skip(1).map(Ident::from_str)
1607 }).map(hir::PathSegment::from_ident).collect(),
1613 segments: path_str.split("::").map(Ident::from_str)
1614 .map(hir::PathSegment::from_ident).collect(),
1617 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1618 if errored || path.def == Def::Err {
1625 /// resolve_hir_path, but takes a callback in case there was an error
1626 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1627 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1629 let namespace = if is_value { ValueNS } else { TypeNS };
1630 let hir::Path { ref segments, span, ref mut def } = *path;
1631 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1632 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1633 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1634 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1635 *def = module.def().unwrap(),
1636 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1637 *def = path_res.base_def(),
1638 PathResult::NonModule(..) =>
1639 if let PathResult::Failed(span, msg, _) = self.resolve_path(
1647 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1649 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1650 PathResult::Indeterminate => unreachable!(),
1651 PathResult::Failed(span, msg, _) => {
1652 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1658 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1659 pub fn new(session: &'a Session,
1663 make_glob_map: MakeGlobMap,
1664 crate_loader: &'a mut CrateLoader<'crateloader>,
1665 arenas: &'a ResolverArenas<'a>)
1666 -> Resolver<'a, 'crateloader> {
1667 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1668 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1669 let graph_root = arenas.alloc_module(ModuleData {
1670 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1671 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1673 let mut module_map = FxHashMap::default();
1674 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1676 let mut definitions = Definitions::new();
1677 DefCollector::new(&mut definitions, Mark::root())
1678 .collect_root(crate_name, session.local_crate_disambiguator());
1680 let mut extern_prelude: FxHashSet<Name> =
1681 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1683 if !attr::contains_name(&krate.attrs, "no_core") {
1684 extern_prelude.insert(Symbol::intern("core"));
1685 if !attr::contains_name(&krate.attrs, "no_std") {
1686 extern_prelude.insert(Symbol::intern("std"));
1687 if session.rust_2018() {
1688 extern_prelude.insert(Symbol::intern("meta"));
1693 let mut invocations = FxHashMap::default();
1694 invocations.insert(Mark::root(),
1695 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1697 let mut macro_defs = FxHashMap::default();
1698 macro_defs.insert(Mark::root(), root_def_id);
1707 // The outermost module has def ID 0; this is not reflected in the
1713 has_self: FxHashSet::default(),
1714 field_names: FxHashMap::default(),
1716 determined_imports: Vec::new(),
1717 indeterminate_imports: Vec::new(),
1719 current_module: graph_root,
1721 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1722 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1723 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1725 label_ribs: Vec::new(),
1727 current_trait_ref: None,
1728 current_self_type: None,
1729 current_self_item: None,
1731 primitive_type_table: PrimitiveTypeTable::new(),
1734 import_map: NodeMap(),
1735 freevars: NodeMap(),
1736 freevars_seen: NodeMap(),
1737 export_map: FxHashMap::default(),
1738 trait_map: NodeMap(),
1740 block_map: NodeMap(),
1741 extern_module_map: FxHashMap::default(),
1742 binding_parent_modules: FxHashMap::default(),
1744 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1745 glob_map: NodeMap(),
1747 used_imports: FxHashSet::default(),
1748 maybe_unused_trait_imports: NodeSet(),
1749 maybe_unused_extern_crates: Vec::new(),
1751 unused_labels: FxHashMap::default(),
1753 privacy_errors: Vec::new(),
1754 ambiguity_errors: Vec::new(),
1755 use_injections: Vec::new(),
1756 macro_expanded_macro_export_errors: BTreeSet::new(),
1759 dummy_binding: arenas.alloc_name_binding(NameBinding {
1760 kind: NameBindingKind::Def(Def::Err, false),
1761 expansion: Mark::root(),
1763 vis: ty::Visibility::Public,
1767 macro_names: FxHashSet::default(),
1768 builtin_macros: FxHashMap::default(),
1769 macro_use_prelude: FxHashMap::default(),
1770 all_macros: FxHashMap::default(),
1771 macro_map: FxHashMap::default(),
1774 local_macro_def_scopes: FxHashMap::default(),
1775 name_already_seen: FxHashMap::default(),
1776 whitelisted_legacy_custom_derives: Vec::new(),
1777 potentially_unused_imports: Vec::new(),
1778 struct_constructors: DefIdMap(),
1779 found_unresolved_macro: false,
1780 unused_macros: FxHashSet::default(),
1781 current_type_ascription: Vec::new(),
1782 injected_crate: None,
1786 pub fn arenas() -> ResolverArenas<'a> {
1790 /// Runs the function on each namespace.
1791 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1797 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1799 match self.macro_defs.get(&ctxt.outer()) {
1800 Some(&def_id) => return def_id,
1801 None => ctxt.remove_mark(),
1806 /// Entry point to crate resolution.
1807 pub fn resolve_crate(&mut self, krate: &Crate) {
1808 ImportResolver { resolver: self }.finalize_imports();
1809 self.current_module = self.graph_root;
1810 self.finalize_current_module_macro_resolutions();
1812 visit::walk_crate(self, krate);
1814 check_unused::check_crate(self, krate);
1815 self.report_errors(krate);
1816 self.crate_loader.postprocess(krate);
1823 normal_ancestor_id: DefId,
1827 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1828 self.arenas.alloc_module(module)
1831 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1832 -> bool /* true if an error was reported */ {
1833 match binding.kind {
1834 NameBindingKind::Import { directive, binding, ref used }
1837 directive.used.set(true);
1838 self.used_imports.insert((directive.id, ns));
1839 self.add_to_glob_map(directive.id, ident);
1840 self.record_use(ident, ns, binding)
1842 NameBindingKind::Import { .. } => false,
1843 NameBindingKind::Ambiguity { b1, b2 } => {
1844 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1851 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1852 if self.make_glob_map {
1853 self.glob_map.entry(id).or_default().insert(ident.name);
1857 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1858 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1859 /// `ident` in the first scope that defines it (or None if no scopes define it).
1861 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1862 /// the items are defined in the block. For example,
1865 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1868 /// g(); // This resolves to the local variable `g` since it shadows the item.
1872 /// Invariant: This must only be called during main resolution, not during
1873 /// import resolution.
1874 fn resolve_ident_in_lexical_scope(&mut self,
1877 record_used_id: Option<NodeId>,
1879 -> Option<LexicalScopeBinding<'a>> {
1880 let record_used = record_used_id.is_some();
1881 assert!(ns == TypeNS || ns == ValueNS);
1883 ident.span = if ident.name == keywords::SelfType.name() {
1884 // FIXME(jseyfried) improve `Self` hygiene
1885 ident.span.with_ctxt(SyntaxContext::empty())
1890 ident = ident.modern_and_legacy();
1893 // Walk backwards up the ribs in scope.
1894 let mut module = self.graph_root;
1895 for i in (0 .. self.ribs[ns].len()).rev() {
1896 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1897 // The ident resolves to a type parameter or local variable.
1898 return Some(LexicalScopeBinding::Def(
1899 self.adjust_local_def(ns, i, def, record_used, path_span)
1903 module = match self.ribs[ns][i].kind {
1904 ModuleRibKind(module) => module,
1905 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1906 // If an invocation of this macro created `ident`, give up on `ident`
1907 // and switch to `ident`'s source from the macro definition.
1908 ident.span.remove_mark();
1914 let item = self.resolve_ident_in_module_unadjusted(
1915 ModuleOrUniformRoot::Module(module),
1922 if let Ok(binding) = item {
1923 // The ident resolves to an item.
1924 return Some(LexicalScopeBinding::Item(binding));
1928 ModuleKind::Block(..) => {}, // We can see through blocks
1933 ident.span = ident.span.modern();
1934 let mut poisoned = None;
1936 let opt_module = if let Some(node_id) = record_used_id {
1937 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1938 node_id, &mut poisoned)
1940 self.hygienic_lexical_parent(module, &mut ident.span)
1942 module = unwrap_or!(opt_module, break);
1943 let orig_current_module = self.current_module;
1944 self.current_module = module; // Lexical resolutions can never be a privacy error.
1945 let result = self.resolve_ident_in_module_unadjusted(
1946 ModuleOrUniformRoot::Module(module),
1953 self.current_module = orig_current_module;
1957 if let Some(node_id) = poisoned {
1958 self.session.buffer_lint_with_diagnostic(
1959 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1960 node_id, ident.span,
1961 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1962 lint::builtin::BuiltinLintDiagnostics::
1963 ProcMacroDeriveResolutionFallback(ident.span),
1966 return Some(LexicalScopeBinding::Item(binding))
1968 Err(Determined) => continue,
1969 Err(Undetermined) =>
1970 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1974 if !module.no_implicit_prelude {
1975 if ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1976 let crate_id = if record_used {
1977 self.crate_loader.process_path_extern(ident.name, ident.span)
1978 } else if let Some(crate_id) =
1979 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
1984 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1985 self.populate_module_if_necessary(&crate_root);
1987 let binding = (crate_root, ty::Visibility::Public,
1988 ident.span, Mark::root()).to_name_binding(self.arenas);
1989 return Some(LexicalScopeBinding::Item(binding));
1991 if ns == TypeNS && is_known_tool(ident.name) {
1992 let binding = (Def::ToolMod, ty::Visibility::Public,
1993 ident.span, Mark::root()).to_name_binding(self.arenas);
1994 return Some(LexicalScopeBinding::Item(binding));
1996 if let Some(prelude) = self.prelude {
1997 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1998 ModuleOrUniformRoot::Module(prelude),
2005 return Some(LexicalScopeBinding::Item(binding));
2013 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2014 -> Option<Module<'a>> {
2015 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2016 return Some(self.macro_def_scope(span.remove_mark()));
2019 if let ModuleKind::Block(..) = module.kind {
2020 return Some(module.parent.unwrap());
2026 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2027 span: &mut Span, node_id: NodeId,
2028 poisoned: &mut Option<NodeId>)
2029 -> Option<Module<'a>> {
2030 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2034 // We need to support the next case under a deprecation warning
2037 // ---- begin: this comes from a proc macro derive
2038 // mod implementation_details {
2039 // // Note that `MyStruct` is not in scope here.
2040 // impl SomeTrait for MyStruct { ... }
2044 // So we have to fall back to the module's parent during lexical resolution in this case.
2045 if let Some(parent) = module.parent {
2046 // Inner module is inside the macro, parent module is outside of the macro.
2047 if module.expansion != parent.expansion &&
2048 module.expansion.is_descendant_of(parent.expansion) {
2049 // The macro is a proc macro derive
2050 if module.expansion.looks_like_proc_macro_derive() {
2051 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2052 *poisoned = Some(node_id);
2053 return module.parent;
2062 fn resolve_ident_in_module(&mut self,
2063 module: ModuleOrUniformRoot<'a>,
2068 -> Result<&'a NameBinding<'a>, Determinacy> {
2069 ident.span = ident.span.modern();
2070 let orig_current_module = self.current_module;
2071 if let ModuleOrUniformRoot::Module(module) = module {
2072 if let Some(def) = ident.span.adjust(module.expansion) {
2073 self.current_module = self.macro_def_scope(def);
2076 let result = self.resolve_ident_in_module_unadjusted(
2077 module, ident, ns, false, record_used, span,
2079 self.current_module = orig_current_module;
2083 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2084 let mut ctxt = ident.span.ctxt();
2085 let mark = if ident.name == keywords::DollarCrate.name() {
2086 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2087 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2088 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2089 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2090 // definitions actually produced by `macro` and `macro` definitions produced by
2091 // `macro_rules!`, but at least such configurations are not stable yet.
2092 ctxt = ctxt.modern_and_legacy();
2093 let mut iter = ctxt.marks().into_iter().rev().peekable();
2094 let mut result = None;
2095 // Find the last modern mark from the end if it exists.
2096 while let Some(&(mark, transparency)) = iter.peek() {
2097 if transparency == Transparency::Opaque {
2098 result = Some(mark);
2104 // Then find the last legacy mark from the end if it exists.
2105 for (mark, transparency) in iter {
2106 if transparency == Transparency::SemiTransparent {
2107 result = Some(mark);
2114 ctxt = ctxt.modern();
2115 ctxt.adjust(Mark::root())
2117 let module = match mark {
2118 Some(def) => self.macro_def_scope(def),
2119 None => return self.graph_root,
2121 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2124 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2125 let mut module = self.get_module(module.normal_ancestor_id);
2126 while module.span.ctxt().modern() != *ctxt {
2127 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2128 module = self.get_module(parent.normal_ancestor_id);
2135 // We maintain a list of value ribs and type ribs.
2137 // Simultaneously, we keep track of the current position in the module
2138 // graph in the `current_module` pointer. When we go to resolve a name in
2139 // the value or type namespaces, we first look through all the ribs and
2140 // then query the module graph. When we resolve a name in the module
2141 // namespace, we can skip all the ribs (since nested modules are not
2142 // allowed within blocks in Rust) and jump straight to the current module
2145 // Named implementations are handled separately. When we find a method
2146 // call, we consult the module node to find all of the implementations in
2147 // scope. This information is lazily cached in the module node. We then
2148 // generate a fake "implementation scope" containing all the
2149 // implementations thus found, for compatibility with old resolve pass.
2151 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2152 where F: FnOnce(&mut Resolver) -> T
2154 let id = self.definitions.local_def_id(id);
2155 let module = self.module_map.get(&id).cloned(); // clones a reference
2156 if let Some(module) = module {
2157 // Move down in the graph.
2158 let orig_module = replace(&mut self.current_module, module);
2159 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2160 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2162 self.finalize_current_module_macro_resolutions();
2165 self.current_module = orig_module;
2166 self.ribs[ValueNS].pop();
2167 self.ribs[TypeNS].pop();
2174 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2175 /// is returned by the given predicate function
2177 /// Stops after meeting a closure.
2178 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2179 where P: Fn(&Rib, Ident) -> Option<R>
2181 for rib in self.label_ribs.iter().rev() {
2184 // If an invocation of this macro created `ident`, give up on `ident`
2185 // and switch to `ident`'s source from the macro definition.
2186 MacroDefinition(def) => {
2187 if def == self.macro_def(ident.span.ctxt()) {
2188 ident.span.remove_mark();
2192 // Do not resolve labels across function boundary
2196 let r = pred(rib, ident);
2204 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2205 self.with_current_self_item(item, |this| {
2206 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2207 let item_def_id = this.definitions.local_def_id(item.id);
2208 if this.session.features_untracked().self_in_typedefs {
2209 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2210 visit::walk_item(this, item);
2213 visit::walk_item(this, item);
2219 fn resolve_item(&mut self, item: &Item) {
2220 let name = item.ident.name;
2221 debug!("(resolving item) resolving {}", name);
2224 ItemKind::Ty(_, ref generics) |
2225 ItemKind::Fn(_, _, ref generics, _) |
2226 ItemKind::Existential(_, ref generics) => {
2227 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2228 |this| visit::walk_item(this, item));
2231 ItemKind::Enum(_, ref generics) |
2232 ItemKind::Struct(_, ref generics) |
2233 ItemKind::Union(_, ref generics) => {
2234 self.resolve_adt(item, generics);
2237 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2238 self.resolve_implementation(generics,
2244 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2245 // Create a new rib for the trait-wide type parameters.
2246 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2247 let local_def_id = this.definitions.local_def_id(item.id);
2248 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2249 this.visit_generics(generics);
2250 walk_list!(this, visit_param_bound, bounds);
2252 for trait_item in trait_items {
2253 let type_parameters = HasTypeParameters(&trait_item.generics,
2254 TraitOrImplItemRibKind);
2255 this.with_type_parameter_rib(type_parameters, |this| {
2256 match trait_item.node {
2257 TraitItemKind::Const(ref ty, ref default) => {
2260 // Only impose the restrictions of
2261 // ConstRibKind for an actual constant
2262 // expression in a provided default.
2263 if let Some(ref expr) = *default{
2264 this.with_constant_rib(|this| {
2265 this.visit_expr(expr);
2269 TraitItemKind::Method(_, _) => {
2270 visit::walk_trait_item(this, trait_item)
2272 TraitItemKind::Type(..) => {
2273 visit::walk_trait_item(this, trait_item)
2275 TraitItemKind::Macro(_) => {
2276 panic!("unexpanded macro in resolve!")
2285 ItemKind::TraitAlias(ref generics, ref bounds) => {
2286 // Create a new rib for the trait-wide type parameters.
2287 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2288 let local_def_id = this.definitions.local_def_id(item.id);
2289 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2290 this.visit_generics(generics);
2291 walk_list!(this, visit_param_bound, bounds);
2296 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2297 self.with_scope(item.id, |this| {
2298 visit::walk_item(this, item);
2302 ItemKind::Static(ref ty, _, ref expr) |
2303 ItemKind::Const(ref ty, ref expr) => {
2304 self.with_item_rib(|this| {
2306 this.with_constant_rib(|this| {
2307 this.visit_expr(expr);
2312 ItemKind::Use(ref use_tree) => {
2313 // Imports are resolved as global by default, add starting root segment.
2315 segments: use_tree.prefix.make_root().into_iter().collect(),
2316 span: use_tree.span,
2318 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2321 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2322 // do nothing, these are just around to be encoded
2325 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2329 /// For the most part, use trees are desugared into `ImportDirective` instances
2330 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2331 /// there is one special case we handle here: an empty nested import like
2332 /// `a::{b::{}}`, which desugares into...no import directives.
2333 fn resolve_use_tree(
2338 use_tree: &ast::UseTree,
2341 match use_tree.kind {
2342 ast::UseTreeKind::Nested(ref items) => {
2344 segments: prefix.segments
2346 .chain(use_tree.prefix.segments.iter())
2349 span: prefix.span.to(use_tree.prefix.span),
2352 if items.is_empty() {
2353 // Resolve prefix of an import with empty braces (issue #28388).
2354 self.smart_resolve_path_with_crate_lint(
2358 PathSource::ImportPrefix,
2359 CrateLint::UsePath { root_id, root_span },
2362 for &(ref tree, nested_id) in items {
2363 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2367 ast::UseTreeKind::Simple(..) => {},
2368 ast::UseTreeKind::Glob => {},
2372 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2373 where F: FnOnce(&mut Resolver)
2375 match type_parameters {
2376 HasTypeParameters(generics, rib_kind) => {
2377 let mut function_type_rib = Rib::new(rib_kind);
2378 let mut seen_bindings = FxHashMap::default();
2379 for param in &generics.params {
2381 GenericParamKind::Lifetime { .. } => {}
2382 GenericParamKind::Type { .. } => {
2383 let ident = param.ident.modern();
2384 debug!("with_type_parameter_rib: {}", param.id);
2386 if seen_bindings.contains_key(&ident) {
2387 let span = seen_bindings.get(&ident).unwrap();
2388 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2392 resolve_error(self, param.ident.span, err);
2394 seen_bindings.entry(ident).or_insert(param.ident.span);
2396 // Plain insert (no renaming).
2397 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2398 function_type_rib.bindings.insert(ident, def);
2399 self.record_def(param.id, PathResolution::new(def));
2403 self.ribs[TypeNS].push(function_type_rib);
2406 NoTypeParameters => {
2413 if let HasTypeParameters(..) = type_parameters {
2414 self.ribs[TypeNS].pop();
2418 fn with_label_rib<F>(&mut self, f: F)
2419 where F: FnOnce(&mut Resolver)
2421 self.label_ribs.push(Rib::new(NormalRibKind));
2423 self.label_ribs.pop();
2426 fn with_item_rib<F>(&mut self, f: F)
2427 where F: FnOnce(&mut Resolver)
2429 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2430 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2432 self.ribs[TypeNS].pop();
2433 self.ribs[ValueNS].pop();
2436 fn with_constant_rib<F>(&mut self, f: F)
2437 where F: FnOnce(&mut Resolver)
2439 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2440 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2442 self.label_ribs.pop();
2443 self.ribs[ValueNS].pop();
2446 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2447 where F: FnOnce(&mut Resolver) -> T
2449 // Handle nested impls (inside fn bodies)
2450 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2451 let result = f(self);
2452 self.current_self_type = previous_value;
2456 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2457 where F: FnOnce(&mut Resolver) -> T
2459 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2460 let result = f(self);
2461 self.current_self_item = previous_value;
2465 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2466 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2467 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2469 let mut new_val = None;
2470 let mut new_id = None;
2471 if let Some(trait_ref) = opt_trait_ref {
2472 let path: Vec<_> = trait_ref.path.segments.iter()
2473 .map(|seg| seg.ident)
2475 let def = self.smart_resolve_path_fragment(
2479 trait_ref.path.span,
2480 PathSource::Trait(AliasPossibility::No),
2481 CrateLint::SimplePath(trait_ref.ref_id),
2483 if def != Def::Err {
2484 new_id = Some(def.def_id());
2485 let span = trait_ref.path.span;
2486 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2493 CrateLint::SimplePath(trait_ref.ref_id),
2496 new_val = Some((module, trait_ref.clone()));
2500 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2501 let result = f(self, new_id);
2502 self.current_trait_ref = original_trait_ref;
2506 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2507 where F: FnOnce(&mut Resolver)
2509 let mut self_type_rib = Rib::new(NormalRibKind);
2511 // plain insert (no renaming, types are not currently hygienic....)
2512 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2513 self.ribs[TypeNS].push(self_type_rib);
2515 self.ribs[TypeNS].pop();
2518 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2519 where F: FnOnce(&mut Resolver)
2521 let self_def = Def::SelfCtor(impl_id);
2522 let mut self_type_rib = Rib::new(NormalRibKind);
2523 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2524 self.ribs[ValueNS].push(self_type_rib);
2526 self.ribs[ValueNS].pop();
2529 fn resolve_implementation(&mut self,
2530 generics: &Generics,
2531 opt_trait_reference: &Option<TraitRef>,
2534 impl_items: &[ImplItem]) {
2535 // If applicable, create a rib for the type parameters.
2536 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2537 // Dummy self type for better errors if `Self` is used in the trait path.
2538 this.with_self_rib(Def::SelfTy(None, None), |this| {
2539 // Resolve the trait reference, if necessary.
2540 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2541 let item_def_id = this.definitions.local_def_id(item_id);
2542 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2543 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2544 // Resolve type arguments in the trait path.
2545 visit::walk_trait_ref(this, trait_ref);
2547 // Resolve the self type.
2548 this.visit_ty(self_type);
2549 // Resolve the type parameters.
2550 this.visit_generics(generics);
2551 // Resolve the items within the impl.
2552 this.with_current_self_type(self_type, |this| {
2553 this.with_self_struct_ctor_rib(item_def_id, |this| {
2554 for impl_item in impl_items {
2555 this.resolve_visibility(&impl_item.vis);
2557 // We also need a new scope for the impl item type parameters.
2558 let type_parameters = HasTypeParameters(&impl_item.generics,
2559 TraitOrImplItemRibKind);
2560 this.with_type_parameter_rib(type_parameters, |this| {
2561 use self::ResolutionError::*;
2562 match impl_item.node {
2563 ImplItemKind::Const(..) => {
2564 // If this is a trait impl, ensure the const
2566 this.check_trait_item(impl_item.ident,
2569 |n, s| ConstNotMemberOfTrait(n, s));
2570 this.with_constant_rib(|this|
2571 visit::walk_impl_item(this, impl_item)
2574 ImplItemKind::Method(..) => {
2575 // If this is a trait impl, ensure the method
2577 this.check_trait_item(impl_item.ident,
2580 |n, s| MethodNotMemberOfTrait(n, s));
2582 visit::walk_impl_item(this, impl_item);
2584 ImplItemKind::Type(ref ty) => {
2585 // If this is a trait impl, ensure the type
2587 this.check_trait_item(impl_item.ident,
2590 |n, s| TypeNotMemberOfTrait(n, s));
2594 ImplItemKind::Existential(ref bounds) => {
2595 // If this is a trait impl, ensure the type
2597 this.check_trait_item(impl_item.ident,
2600 |n, s| TypeNotMemberOfTrait(n, s));
2602 for bound in bounds {
2603 this.visit_param_bound(bound);
2606 ImplItemKind::Macro(_) =>
2607 panic!("unexpanded macro in resolve!"),
2619 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2620 where F: FnOnce(Name, &str) -> ResolutionError
2622 // If there is a TraitRef in scope for an impl, then the method must be in the
2624 if let Some((module, _)) = self.current_trait_ref {
2625 if self.resolve_ident_in_module(
2626 ModuleOrUniformRoot::Module(module),
2632 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2633 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2638 fn resolve_local(&mut self, local: &Local) {
2639 // Resolve the type.
2640 walk_list!(self, visit_ty, &local.ty);
2642 // Resolve the initializer.
2643 walk_list!(self, visit_expr, &local.init);
2645 // Resolve the pattern.
2646 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2649 // build a map from pattern identifiers to binding-info's.
2650 // this is done hygienically. This could arise for a macro
2651 // that expands into an or-pattern where one 'x' was from the
2652 // user and one 'x' came from the macro.
2653 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2654 let mut binding_map = FxHashMap::default();
2656 pat.walk(&mut |pat| {
2657 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2658 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2659 Some(Def::Local(..)) => true,
2662 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2663 binding_map.insert(ident, binding_info);
2672 // check that all of the arms in an or-pattern have exactly the
2673 // same set of bindings, with the same binding modes for each.
2674 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2675 if pats.is_empty() {
2679 let mut missing_vars = FxHashMap::default();
2680 let mut inconsistent_vars = FxHashMap::default();
2681 for (i, p) in pats.iter().enumerate() {
2682 let map_i = self.binding_mode_map(&p);
2684 for (j, q) in pats.iter().enumerate() {
2689 let map_j = self.binding_mode_map(&q);
2690 for (&key, &binding_i) in &map_i {
2691 if map_j.is_empty() { // Account for missing bindings when
2692 let binding_error = missing_vars // map_j has none.
2694 .or_insert(BindingError {
2696 origin: BTreeSet::new(),
2697 target: BTreeSet::new(),
2699 binding_error.origin.insert(binding_i.span);
2700 binding_error.target.insert(q.span);
2702 for (&key_j, &binding_j) in &map_j {
2703 match map_i.get(&key_j) {
2704 None => { // missing binding
2705 let binding_error = missing_vars
2707 .or_insert(BindingError {
2709 origin: BTreeSet::new(),
2710 target: BTreeSet::new(),
2712 binding_error.origin.insert(binding_j.span);
2713 binding_error.target.insert(p.span);
2715 Some(binding_i) => { // check consistent binding
2716 if binding_i.binding_mode != binding_j.binding_mode {
2719 .or_insert((binding_j.span, binding_i.span));
2727 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2728 missing_vars.sort();
2729 for (_, v) in missing_vars {
2731 *v.origin.iter().next().unwrap(),
2732 ResolutionError::VariableNotBoundInPattern(v));
2734 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2735 inconsistent_vars.sort();
2736 for (name, v) in inconsistent_vars {
2737 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2741 fn resolve_arm(&mut self, arm: &Arm) {
2742 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2744 let mut bindings_list = FxHashMap::default();
2745 for pattern in &arm.pats {
2746 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2749 // This has to happen *after* we determine which pat_idents are variants
2750 self.check_consistent_bindings(&arm.pats);
2752 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2753 self.visit_expr(expr)
2755 self.visit_expr(&arm.body);
2757 self.ribs[ValueNS].pop();
2760 fn resolve_block(&mut self, block: &Block) {
2761 debug!("(resolving block) entering block");
2762 // Move down in the graph, if there's an anonymous module rooted here.
2763 let orig_module = self.current_module;
2764 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2766 let mut num_macro_definition_ribs = 0;
2767 if let Some(anonymous_module) = anonymous_module {
2768 debug!("(resolving block) found anonymous module, moving down");
2769 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2770 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2771 self.current_module = anonymous_module;
2772 self.finalize_current_module_macro_resolutions();
2774 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2777 // Descend into the block.
2778 for stmt in &block.stmts {
2779 if let ast::StmtKind::Item(ref item) = stmt.node {
2780 if let ast::ItemKind::MacroDef(..) = item.node {
2781 num_macro_definition_ribs += 1;
2782 let def = self.definitions.local_def_id(item.id);
2783 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2784 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2788 self.visit_stmt(stmt);
2792 self.current_module = orig_module;
2793 for _ in 0 .. num_macro_definition_ribs {
2794 self.ribs[ValueNS].pop();
2795 self.label_ribs.pop();
2797 self.ribs[ValueNS].pop();
2798 if anonymous_module.is_some() {
2799 self.ribs[TypeNS].pop();
2801 debug!("(resolving block) leaving block");
2804 fn fresh_binding(&mut self,
2807 outer_pat_id: NodeId,
2808 pat_src: PatternSource,
2809 bindings: &mut FxHashMap<Ident, NodeId>)
2811 // Add the binding to the local ribs, if it
2812 // doesn't already exist in the bindings map. (We
2813 // must not add it if it's in the bindings map
2814 // because that breaks the assumptions later
2815 // passes make about or-patterns.)
2816 let ident = ident.modern_and_legacy();
2817 let mut def = Def::Local(pat_id);
2818 match bindings.get(&ident).cloned() {
2819 Some(id) if id == outer_pat_id => {
2820 // `Variant(a, a)`, error
2824 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2828 Some(..) if pat_src == PatternSource::FnParam => {
2829 // `fn f(a: u8, a: u8)`, error
2833 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2837 Some(..) if pat_src == PatternSource::Match ||
2838 pat_src == PatternSource::IfLet ||
2839 pat_src == PatternSource::WhileLet => {
2840 // `Variant1(a) | Variant2(a)`, ok
2841 // Reuse definition from the first `a`.
2842 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2845 span_bug!(ident.span, "two bindings with the same name from \
2846 unexpected pattern source {:?}", pat_src);
2849 // A completely fresh binding, add to the lists if it's valid.
2850 if ident.name != keywords::Invalid.name() {
2851 bindings.insert(ident, outer_pat_id);
2852 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2857 PathResolution::new(def)
2860 fn resolve_pattern(&mut self,
2862 pat_src: PatternSource,
2863 // Maps idents to the node ID for the
2864 // outermost pattern that binds them.
2865 bindings: &mut FxHashMap<Ident, NodeId>) {
2866 // Visit all direct subpatterns of this pattern.
2867 let outer_pat_id = pat.id;
2868 pat.walk(&mut |pat| {
2870 PatKind::Ident(bmode, ident, ref opt_pat) => {
2871 // First try to resolve the identifier as some existing
2872 // entity, then fall back to a fresh binding.
2873 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2875 .and_then(LexicalScopeBinding::item);
2876 let resolution = binding.map(NameBinding::def).and_then(|def| {
2877 let is_syntactic_ambiguity = opt_pat.is_none() &&
2878 bmode == BindingMode::ByValue(Mutability::Immutable);
2880 Def::StructCtor(_, CtorKind::Const) |
2881 Def::VariantCtor(_, CtorKind::Const) |
2882 Def::Const(..) if is_syntactic_ambiguity => {
2883 // Disambiguate in favor of a unit struct/variant
2884 // or constant pattern.
2885 self.record_use(ident, ValueNS, binding.unwrap());
2886 Some(PathResolution::new(def))
2888 Def::StructCtor(..) | Def::VariantCtor(..) |
2889 Def::Const(..) | Def::Static(..) => {
2890 // This is unambiguously a fresh binding, either syntactically
2891 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2892 // to something unusable as a pattern (e.g. constructor function),
2893 // but we still conservatively report an error, see
2894 // issues/33118#issuecomment-233962221 for one reason why.
2898 ResolutionError::BindingShadowsSomethingUnacceptable(
2899 pat_src.descr(), ident.name, binding.unwrap())
2903 Def::Fn(..) | Def::Err => {
2904 // These entities are explicitly allowed
2905 // to be shadowed by fresh bindings.
2909 span_bug!(ident.span, "unexpected definition for an \
2910 identifier in pattern: {:?}", def);
2913 }).unwrap_or_else(|| {
2914 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2917 self.record_def(pat.id, resolution);
2920 PatKind::TupleStruct(ref path, ..) => {
2921 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2924 PatKind::Path(ref qself, ref path) => {
2925 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2928 PatKind::Struct(ref path, ..) => {
2929 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2937 visit::walk_pat(self, pat);
2940 // High-level and context dependent path resolution routine.
2941 // Resolves the path and records the resolution into definition map.
2942 // If resolution fails tries several techniques to find likely
2943 // resolution candidates, suggest imports or other help, and report
2944 // errors in user friendly way.
2945 fn smart_resolve_path(&mut self,
2947 qself: Option<&QSelf>,
2951 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2954 /// A variant of `smart_resolve_path` where you also specify extra
2955 /// information about where the path came from; this extra info is
2956 /// sometimes needed for the lint that recommends rewriting
2957 /// absolute paths to `crate`, so that it knows how to frame the
2958 /// suggestion. If you are just resolving a path like `foo::bar`
2959 /// that appears...somewhere, though, then you just want
2960 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2961 /// already provides.
2962 fn smart_resolve_path_with_crate_lint(
2965 qself: Option<&QSelf>,
2968 crate_lint: CrateLint
2969 ) -> PathResolution {
2970 let segments = &path.segments.iter()
2971 .map(|seg| seg.ident)
2972 .collect::<Vec<_>>();
2973 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2976 fn smart_resolve_path_fragment(&mut self,
2978 qself: Option<&QSelf>,
2982 crate_lint: CrateLint)
2984 let ident_span = path.last().map_or(span, |ident| ident.span);
2985 let ns = source.namespace();
2986 let is_expected = &|def| source.is_expected(def);
2987 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2989 // Base error is amended with one short label and possibly some longer helps/notes.
2990 let report_errors = |this: &mut Self, def: Option<Def>| {
2991 // Make the base error.
2992 let expected = source.descr_expected();
2993 let path_str = names_to_string(path);
2994 let item_str = path.last().unwrap();
2995 let code = source.error_code(def.is_some());
2996 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2997 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2998 format!("not a {}", expected),
3001 let item_span = path.last().unwrap().span;
3002 let (mod_prefix, mod_str) = if path.len() == 1 {
3003 (String::new(), "this scope".to_string())
3004 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
3005 (String::new(), "the crate root".to_string())
3007 let mod_path = &path[..path.len() - 1];
3008 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
3009 false, span, CrateLint::No) {
3010 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3013 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3014 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
3016 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3017 format!("not found in {}", mod_str),
3020 let code = DiagnosticId::Error(code.into());
3021 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3023 // Emit help message for fake-self from other languages like `this`(javascript)
3024 if ["this", "my"].contains(&&*item_str.as_str())
3025 && this.self_value_is_available(path[0].span, span) {
3026 err.span_suggestion_with_applicability(
3030 Applicability::MaybeIncorrect,
3034 // Emit special messages for unresolved `Self` and `self`.
3035 if is_self_type(path, ns) {
3036 __diagnostic_used!(E0411);
3037 err.code(DiagnosticId::Error("E0411".into()));
3038 let available_in = if this.session.features_untracked().self_in_typedefs {
3039 "impls, traits, and type definitions"
3043 err.span_label(span, format!("`Self` is only available in {}", available_in));
3044 if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
3045 err.help("add #![feature(self_in_typedefs)] to the crate attributes \
3048 return (err, Vec::new());
3050 if is_self_value(path, ns) {
3051 __diagnostic_used!(E0424);
3052 err.code(DiagnosticId::Error("E0424".into()));
3053 err.span_label(span, format!("`self` value is a keyword \
3055 methods with `self` parameter"));
3056 return (err, Vec::new());
3059 // Try to lookup the name in more relaxed fashion for better error reporting.
3060 let ident = *path.last().unwrap();
3061 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3062 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3063 let enum_candidates =
3064 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3065 let mut enum_candidates = enum_candidates.iter()
3066 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3067 enum_candidates.sort();
3068 for (sp, variant_path, enum_path) in enum_candidates {
3070 let msg = format!("there is an enum variant `{}`, \
3076 err.span_suggestion_with_applicability(
3078 "you can try using the variant's enum",
3080 Applicability::MachineApplicable,
3085 if path.len() == 1 && this.self_type_is_available(span) {
3086 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3087 let self_is_available = this.self_value_is_available(path[0].span, span);
3089 AssocSuggestion::Field => {
3090 err.span_suggestion_with_applicability(
3093 format!("self.{}", path_str),
3094 Applicability::MachineApplicable,
3096 if !self_is_available {
3097 err.span_label(span, format!("`self` value is a keyword \
3099 methods with `self` parameter"));
3102 AssocSuggestion::MethodWithSelf if self_is_available => {
3103 err.span_suggestion_with_applicability(
3106 format!("self.{}", path_str),
3107 Applicability::MachineApplicable,
3110 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3111 err.span_suggestion_with_applicability(
3114 format!("Self::{}", path_str),
3115 Applicability::MachineApplicable,
3119 return (err, candidates);
3123 let mut levenshtein_worked = false;
3126 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3127 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3128 levenshtein_worked = true;
3131 // Try context dependent help if relaxed lookup didn't work.
3132 if let Some(def) = def {
3133 match (def, source) {
3134 (Def::Macro(..), _) => {
3135 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3136 return (err, candidates);
3138 (Def::TyAlias(..), PathSource::Trait(_)) => {
3139 err.span_label(span, "type aliases cannot be used for traits");
3140 return (err, candidates);
3142 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3143 ExprKind::Field(_, ident) => {
3144 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3146 return (err, candidates);
3148 ExprKind::MethodCall(ref segment, ..) => {
3149 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3150 path_str, segment.ident));
3151 return (err, candidates);
3155 (Def::Enum(..), PathSource::TupleStruct)
3156 | (Def::Enum(..), PathSource::Expr(..)) => {
3157 if let Some(variants) = this.collect_enum_variants(def) {
3158 err.note(&format!("did you mean to use one \
3159 of the following variants?\n{}",
3161 .map(|suggestion| path_names_to_string(suggestion))
3162 .map(|suggestion| format!("- `{}`", suggestion))
3163 .collect::<Vec<_>>()
3167 err.note("did you mean to use one of the enum's variants?");
3169 return (err, candidates);
3171 (Def::Struct(def_id), _) if ns == ValueNS => {
3172 if let Some((ctor_def, ctor_vis))
3173 = this.struct_constructors.get(&def_id).cloned() {
3174 let accessible_ctor = this.is_accessible(ctor_vis);
3175 if is_expected(ctor_def) && !accessible_ctor {
3176 err.span_label(span, format!("constructor is not visible \
3177 here due to private fields"));
3180 // HACK(estebank): find a better way to figure out that this was a
3181 // parser issue where a struct literal is being used on an expression
3182 // where a brace being opened means a block is being started. Look
3183 // ahead for the next text to see if `span` is followed by a `{`.
3184 let sm = this.session.source_map();
3187 sp = sm.next_point(sp);
3188 match sm.span_to_snippet(sp) {
3189 Ok(ref snippet) => {
3190 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3197 let followed_by_brace = match sm.span_to_snippet(sp) {
3198 Ok(ref snippet) if snippet == "{" => true,
3202 PathSource::Expr(Some(parent)) => {
3204 ExprKind::MethodCall(ref path_assignment, _) => {
3205 err.span_suggestion_with_applicability(
3206 sm.start_point(parent.span)
3207 .to(path_assignment.ident.span),
3208 "use `::` to access an associated function",
3211 path_assignment.ident),
3212 Applicability::MaybeIncorrect
3214 return (err, candidates);
3219 format!("did you mean `{} {{ /* fields */ }}`?",
3222 return (err, candidates);
3226 PathSource::Expr(None) if followed_by_brace == true => {
3229 format!("did you mean `({} {{ /* fields */ }})`?",
3232 return (err, candidates);
3237 format!("did you mean `{} {{ /* fields */ }}`?",
3240 return (err, candidates);
3244 return (err, candidates);
3246 (Def::Union(..), _) |
3247 (Def::Variant(..), _) |
3248 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3249 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3251 return (err, candidates);
3253 (Def::SelfTy(..), _) if ns == ValueNS => {
3254 err.span_label(span, fallback_label);
3255 err.note("can't use `Self` as a constructor, you must use the \
3256 implemented struct");
3257 return (err, candidates);
3259 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3260 err.note("can't use a type alias as a constructor");
3261 return (err, candidates);
3268 if !levenshtein_worked {
3269 err.span_label(base_span, fallback_label);
3270 this.type_ascription_suggestion(&mut err, base_span);
3274 let report_errors = |this: &mut Self, def: Option<Def>| {
3275 let (err, candidates) = report_errors(this, def);
3276 let def_id = this.current_module.normal_ancestor_id;
3277 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3278 let better = def.is_some();
3279 this.use_injections.push(UseError { err, candidates, node_id, better });
3280 err_path_resolution()
3283 let resolution = match self.resolve_qpath_anywhere(
3289 source.defer_to_typeck(),
3290 source.global_by_default(),
3293 Some(resolution) if resolution.unresolved_segments() == 0 => {
3294 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3297 // Add a temporary hack to smooth the transition to new struct ctor
3298 // visibility rules. See #38932 for more details.
3300 if let Def::Struct(def_id) = resolution.base_def() {
3301 if let Some((ctor_def, ctor_vis))
3302 = self.struct_constructors.get(&def_id).cloned() {
3303 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3304 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3305 self.session.buffer_lint(lint, id, span,
3306 "private struct constructors are not usable through \
3307 re-exports in outer modules",
3309 res = Some(PathResolution::new(ctor_def));
3314 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3317 Some(resolution) if source.defer_to_typeck() => {
3318 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3319 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3320 // it needs to be added to the trait map.
3322 let item_name = *path.last().unwrap();
3323 let traits = self.get_traits_containing_item(item_name, ns);
3324 self.trait_map.insert(id, traits);
3328 _ => report_errors(self, None)
3331 if let PathSource::TraitItem(..) = source {} else {
3332 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3333 self.record_def(id, resolution);
3338 fn type_ascription_suggestion(&self,
3339 err: &mut DiagnosticBuilder,
3341 debug!("type_ascription_suggetion {:?}", base_span);
3342 let cm = self.session.source_map();
3343 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3344 if let Some(sp) = self.current_type_ascription.last() {
3346 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3347 sp = cm.next_point(sp);
3348 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3349 debug!("snippet {:?}", snippet);
3350 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3351 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3352 debug!("{:?} {:?}", line_sp, line_base_sp);
3354 err.span_label(base_span,
3355 "expecting a type here because of type ascription");
3356 if line_sp != line_base_sp {
3357 err.span_suggestion_short_with_applicability(
3359 "did you mean to use `;` here instead?",
3361 Applicability::MaybeIncorrect,
3365 } else if !snippet.trim().is_empty() {
3366 debug!("tried to find type ascription `:` token, couldn't find it");
3376 fn self_type_is_available(&mut self, span: Span) -> bool {
3377 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3378 TypeNS, None, span);
3379 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3382 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3383 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3384 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3385 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3388 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3389 fn resolve_qpath_anywhere(&mut self,
3391 qself: Option<&QSelf>,
3393 primary_ns: Namespace,
3395 defer_to_typeck: bool,
3396 global_by_default: bool,
3397 crate_lint: CrateLint)
3398 -> Option<PathResolution> {
3399 let mut fin_res = None;
3400 // FIXME: can't resolve paths in macro namespace yet, macros are
3401 // processed by the little special hack below.
3402 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3403 if i == 0 || ns != primary_ns {
3404 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3405 // If defer_to_typeck, then resolution > no resolution,
3406 // otherwise full resolution > partial resolution > no resolution.
3407 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3409 res => if fin_res.is_none() { fin_res = res },
3413 if primary_ns != MacroNS &&
3414 (self.macro_names.contains(&path[0].modern()) ||
3415 self.builtin_macros.get(&path[0].name).cloned()
3416 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3417 self.macro_use_prelude.get(&path[0].name).cloned()
3418 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3419 // Return some dummy definition, it's enough for error reporting.
3421 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3427 /// Handles paths that may refer to associated items.
3428 fn resolve_qpath(&mut self,
3430 qself: Option<&QSelf>,
3434 global_by_default: bool,
3435 crate_lint: CrateLint)
3436 -> Option<PathResolution> {
3438 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3439 ns={:?}, span={:?}, global_by_default={:?})",
3448 if let Some(qself) = qself {
3449 if qself.position == 0 {
3450 // This is a case like `<T>::B`, where there is no
3451 // trait to resolve. In that case, we leave the `B`
3452 // segment to be resolved by type-check.
3453 return Some(PathResolution::with_unresolved_segments(
3454 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3458 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3460 // Currently, `path` names the full item (`A::B::C`, in
3461 // our example). so we extract the prefix of that that is
3462 // the trait (the slice upto and including
3463 // `qself.position`). And then we recursively resolve that,
3464 // but with `qself` set to `None`.
3466 // However, setting `qself` to none (but not changing the
3467 // span) loses the information about where this path
3468 // *actually* appears, so for the purposes of the crate
3469 // lint we pass along information that this is the trait
3470 // name from a fully qualified path, and this also
3471 // contains the full span (the `CrateLint::QPathTrait`).
3472 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3473 let res = self.smart_resolve_path_fragment(
3476 &path[..qself.position + 1],
3478 PathSource::TraitItem(ns),
3479 CrateLint::QPathTrait {
3481 qpath_span: qself.path_span,
3485 // The remaining segments (the `C` in our example) will
3486 // have to be resolved by type-check, since that requires doing
3487 // trait resolution.
3488 return Some(PathResolution::with_unresolved_segments(
3489 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3493 let result = match self.resolve_path(
3501 PathResult::NonModule(path_res) => path_res,
3502 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3503 PathResolution::new(module.def().unwrap())
3505 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3506 // don't report an error right away, but try to fallback to a primitive type.
3507 // So, we are still able to successfully resolve something like
3509 // use std::u8; // bring module u8 in scope
3510 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3511 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3512 // // not to non-existent std::u8::max_value
3515 // Such behavior is required for backward compatibility.
3516 // The same fallback is used when `a` resolves to nothing.
3517 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3518 PathResult::Failed(..)
3519 if (ns == TypeNS || path.len() > 1) &&
3520 self.primitive_type_table.primitive_types
3521 .contains_key(&path[0].name) => {
3522 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3523 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3525 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3526 PathResolution::new(module.def().unwrap()),
3527 PathResult::Failed(span, msg, false) => {
3528 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3529 err_path_resolution()
3531 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3532 PathResult::Failed(..) => return None,
3533 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3536 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3537 path[0].name != keywords::CrateRoot.name() &&
3538 path[0].name != keywords::DollarCrate.name() {
3539 let unqualified_result = {
3540 match self.resolve_path(
3542 &[*path.last().unwrap()],
3548 PathResult::NonModule(path_res) => path_res.base_def(),
3549 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3550 module.def().unwrap(),
3551 _ => return Some(result),
3554 if result.base_def() == unqualified_result {
3555 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3556 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3565 base_module: Option<ModuleOrUniformRoot<'a>>,
3567 opt_ns: Option<Namespace>, // `None` indicates a module path
3570 crate_lint: CrateLint,
3571 ) -> PathResult<'a> {
3572 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3573 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3574 record_used, path_span, crate_lint)
3577 fn resolve_path_with_parent_scope(
3579 base_module: Option<ModuleOrUniformRoot<'a>>,
3581 opt_ns: Option<Namespace>, // `None` indicates a module path
3582 parent_scope: &ParentScope<'a>,
3585 crate_lint: CrateLint,
3586 ) -> PathResult<'a> {
3587 let mut module = base_module;
3588 let mut allow_super = true;
3589 let mut second_binding = None;
3590 self.current_module = parent_scope.module;
3593 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3594 path_span={:?}, crate_lint={:?})",
3602 for (i, &ident) in path.iter().enumerate() {
3603 debug!("resolve_path ident {} {:?}", i, ident);
3604 let is_last = i == path.len() - 1;
3605 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3606 let name = ident.name;
3608 allow_super &= ns == TypeNS &&
3609 (name == keywords::SelfValue.name() ||
3610 name == keywords::Super.name());
3613 if allow_super && name == keywords::Super.name() {
3614 let mut ctxt = ident.span.ctxt().modern();
3615 let self_module = match i {
3616 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3618 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3622 if let Some(self_module) = self_module {
3623 if let Some(parent) = self_module.parent {
3624 module = Some(ModuleOrUniformRoot::Module(
3625 self.resolve_self(&mut ctxt, parent)));
3629 let msg = "There are too many initial `super`s.".to_string();
3630 return PathResult::Failed(ident.span, msg, false);
3633 if name == keywords::SelfValue.name() {
3634 let mut ctxt = ident.span.ctxt().modern();
3635 module = Some(ModuleOrUniformRoot::Module(
3636 self.resolve_self(&mut ctxt, self.current_module)));
3639 if name == keywords::Extern.name() ||
3640 name == keywords::CrateRoot.name() &&
3641 self.session.rust_2018() {
3642 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3645 if name == keywords::CrateRoot.name() ||
3646 name == keywords::Crate.name() ||
3647 name == keywords::DollarCrate.name() {
3648 // `::a::b`, `crate::a::b` or `$crate::a::b`
3649 module = Some(ModuleOrUniformRoot::Module(
3650 self.resolve_crate_root(ident)));
3656 // Report special messages for path segment keywords in wrong positions.
3657 if ident.is_path_segment_keyword() && i != 0 {
3658 let name_str = if name == keywords::CrateRoot.name() {
3659 "crate root".to_string()
3661 format!("`{}`", name)
3663 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3664 format!("global paths cannot start with {}", name_str)
3666 format!("{} in paths can only be used in start position", name_str)
3668 return PathResult::Failed(ident.span, msg, false);
3671 let binding = if let Some(module) = module {
3672 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3673 } else if opt_ns == Some(MacroNS) {
3674 assert!(ns == TypeNS);
3675 self.early_resolve_ident_in_lexical_scope(ident, ns, None, parent_scope,
3676 record_used, record_used, path_span)
3678 let record_used_id =
3679 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3680 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3681 // we found a locally-imported or available item/module
3682 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3683 // we found a local variable or type param
3684 Some(LexicalScopeBinding::Def(def))
3685 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3686 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3690 _ => Err(if record_used { Determined } else { Undetermined }),
3697 second_binding = Some(binding);
3699 let def = binding.def();
3700 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3701 if let Some(next_module) = binding.module() {
3702 module = Some(ModuleOrUniformRoot::Module(next_module));
3703 } else if def == Def::ToolMod && i + 1 != path.len() {
3704 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3705 return PathResult::NonModule(PathResolution::new(def));
3706 } else if def == Def::Err {
3707 return PathResult::NonModule(err_path_resolution());
3708 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3709 self.lint_if_path_starts_with_module(
3715 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3716 def, path.len() - i - 1
3719 return PathResult::Failed(ident.span,
3720 format!("Not a module `{}`", ident),
3724 Err(Undetermined) => return PathResult::Indeterminate,
3725 Err(Determined) => {
3726 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3727 if opt_ns.is_some() && !module.is_normal() {
3728 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3729 module.def().unwrap(), path.len() - i
3733 let module_def = match module {
3734 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3737 let msg = if module_def == self.graph_root.def() {
3738 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3739 let mut candidates =
3740 self.lookup_import_candidates(name, TypeNS, is_mod);
3741 candidates.sort_by_cached_key(|c| {
3742 (c.path.segments.len(), c.path.to_string())
3744 if let Some(candidate) = candidates.get(0) {
3745 format!("Did you mean `{}`?", candidate.path)
3747 format!("Maybe a missing `extern crate {};`?", ident)
3750 format!("Use of undeclared type or module `{}`", ident)
3752 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3754 return PathResult::Failed(ident.span, msg, is_last);
3759 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3761 PathResult::Module(module.unwrap_or_else(|| {
3762 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3767 fn lint_if_path_starts_with_module(
3769 crate_lint: CrateLint,
3772 second_binding: Option<&NameBinding>,
3774 // In the 2018 edition this lint is a hard error, so nothing to do
3775 if self.session.rust_2018() {
3779 let (diag_id, diag_span) = match crate_lint {
3780 CrateLint::No => return,
3781 CrateLint::SimplePath(id) => (id, path_span),
3782 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3783 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3786 let first_name = match path.get(0) {
3787 Some(ident) => ident.name,
3791 // We're only interested in `use` paths which should start with
3792 // `{{root}}` or `extern` currently.
3793 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3798 // If this import looks like `crate::...` it's already good
3799 Some(ident) if ident.name == keywords::Crate.name() => return,
3800 // Otherwise go below to see if it's an extern crate
3802 // If the path has length one (and it's `CrateRoot` most likely)
3803 // then we don't know whether we're gonna be importing a crate or an
3804 // item in our crate. Defer this lint to elsewhere
3808 // If the first element of our path was actually resolved to an
3809 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3810 // warning, this looks all good!
3811 if let Some(binding) = second_binding {
3812 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3813 // Careful: we still want to rewrite paths from
3814 // renamed extern crates.
3815 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3821 let diag = lint::builtin::BuiltinLintDiagnostics
3822 ::AbsPathWithModule(diag_span);
3823 self.session.buffer_lint_with_diagnostic(
3824 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3826 "absolute paths must start with `self`, `super`, \
3827 `crate`, or an external crate name in the 2018 edition",
3831 // Resolve a local definition, potentially adjusting for closures.
3832 fn adjust_local_def(&mut self,
3837 span: Span) -> Def {
3838 let ribs = &self.ribs[ns][rib_index + 1..];
3840 // An invalid forward use of a type parameter from a previous default.
3841 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3843 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3845 assert_eq!(def, Def::Err);
3851 span_bug!(span, "unexpected {:?} in bindings", def)
3853 Def::Local(node_id) => {
3856 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3857 ForwardTyParamBanRibKind => {
3858 // Nothing to do. Continue.
3860 ClosureRibKind(function_id) => {
3863 let seen = self.freevars_seen
3866 if let Some(&index) = seen.get(&node_id) {
3867 def = Def::Upvar(node_id, index, function_id);
3870 let vec = self.freevars
3873 let depth = vec.len();
3874 def = Def::Upvar(node_id, depth, function_id);
3881 seen.insert(node_id, depth);
3884 ItemRibKind | TraitOrImplItemRibKind => {
3885 // This was an attempt to access an upvar inside a
3886 // named function item. This is not allowed, so we
3889 resolve_error(self, span,
3890 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3894 ConstantItemRibKind => {
3895 // Still doesn't deal with upvars
3897 resolve_error(self, span,
3898 ResolutionError::AttemptToUseNonConstantValueInConstant);
3905 Def::TyParam(..) | Def::SelfTy(..) => {
3908 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3909 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3910 ConstantItemRibKind => {
3911 // Nothing to do. Continue.
3914 // This was an attempt to use a type parameter outside
3917 resolve_error(self, span,
3918 ResolutionError::TypeParametersFromOuterFunction(def));
3930 fn lookup_assoc_candidate<FilterFn>(&mut self,
3933 filter_fn: FilterFn)
3934 -> Option<AssocSuggestion>
3935 where FilterFn: Fn(Def) -> bool
3937 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3939 TyKind::Path(None, _) => Some(t.id),
3940 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3941 // This doesn't handle the remaining `Ty` variants as they are not
3942 // that commonly the self_type, it might be interesting to provide
3943 // support for those in future.
3948 // Fields are generally expected in the same contexts as locals.
3949 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3950 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3951 // Look for a field with the same name in the current self_type.
3952 if let Some(resolution) = self.def_map.get(&node_id) {
3953 match resolution.base_def() {
3954 Def::Struct(did) | Def::Union(did)
3955 if resolution.unresolved_segments() == 0 => {
3956 if let Some(field_names) = self.field_names.get(&did) {
3957 if field_names.iter().any(|&field_name| ident.name == field_name) {
3958 return Some(AssocSuggestion::Field);
3968 // Look for associated items in the current trait.
3969 if let Some((module, _)) = self.current_trait_ref {
3970 if let Ok(binding) = self.resolve_ident_in_module(
3971 ModuleOrUniformRoot::Module(module),
3977 let def = binding.def();
3979 return Some(if self.has_self.contains(&def.def_id()) {
3980 AssocSuggestion::MethodWithSelf
3982 AssocSuggestion::AssocItem
3991 fn lookup_typo_candidate<FilterFn>(&mut self,
3994 filter_fn: FilterFn,
3997 where FilterFn: Fn(Def) -> bool
3999 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4000 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4001 if let Some(binding) = resolution.borrow().binding {
4002 if filter_fn(binding.def()) {
4003 names.push(ident.name);
4009 let mut names = Vec::new();
4010 if path.len() == 1 {
4011 // Search in lexical scope.
4012 // Walk backwards up the ribs in scope and collect candidates.
4013 for rib in self.ribs[ns].iter().rev() {
4014 // Locals and type parameters
4015 for (ident, def) in &rib.bindings {
4016 if filter_fn(*def) {
4017 names.push(ident.name);
4021 if let ModuleRibKind(module) = rib.kind {
4022 // Items from this module
4023 add_module_candidates(module, &mut names);
4025 if let ModuleKind::Block(..) = module.kind {
4026 // We can see through blocks
4028 // Items from the prelude
4029 if !module.no_implicit_prelude {
4030 names.extend(self.extern_prelude.iter().cloned());
4031 if let Some(prelude) = self.prelude {
4032 add_module_candidates(prelude, &mut names);
4039 // Add primitive types to the mix
4040 if filter_fn(Def::PrimTy(Bool)) {
4042 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4046 // Search in module.
4047 let mod_path = &path[..path.len() - 1];
4048 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
4049 false, span, CrateLint::No) {
4050 if let ModuleOrUniformRoot::Module(module) = module {
4051 add_module_candidates(module, &mut names);
4056 let name = path[path.len() - 1].name;
4057 // Make sure error reporting is deterministic.
4058 names.sort_by_cached_key(|name| name.as_str());
4059 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4060 Some(found) if found != name => Some(found),
4065 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4066 where F: FnOnce(&mut Resolver)
4068 if let Some(label) = label {
4069 self.unused_labels.insert(id, label.ident.span);
4070 let def = Def::Label(id);
4071 self.with_label_rib(|this| {
4072 let ident = label.ident.modern_and_legacy();
4073 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4081 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4082 self.with_resolved_label(label, id, |this| this.visit_block(block));
4085 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4086 // First, record candidate traits for this expression if it could
4087 // result in the invocation of a method call.
4089 self.record_candidate_traits_for_expr_if_necessary(expr);
4091 // Next, resolve the node.
4093 ExprKind::Path(ref qself, ref path) => {
4094 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4095 visit::walk_expr(self, expr);
4098 ExprKind::Struct(ref path, ..) => {
4099 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4100 visit::walk_expr(self, expr);
4103 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4104 let def = self.search_label(label.ident, |rib, ident| {
4105 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4109 // Search again for close matches...
4110 // Picks the first label that is "close enough", which is not necessarily
4111 // the closest match
4112 let close_match = self.search_label(label.ident, |rib, ident| {
4113 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4114 find_best_match_for_name(names, &*ident.as_str(), None)
4116 self.record_def(expr.id, err_path_resolution());
4119 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4122 Some(Def::Label(id)) => {
4123 // Since this def is a label, it is never read.
4124 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4125 self.unused_labels.remove(&id);
4128 span_bug!(expr.span, "label wasn't mapped to a label def!");
4132 // visit `break` argument if any
4133 visit::walk_expr(self, expr);
4136 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4137 self.visit_expr(subexpression);
4139 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4140 let mut bindings_list = FxHashMap::default();
4142 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4144 // This has to happen *after* we determine which pat_idents are variants
4145 self.check_consistent_bindings(pats);
4146 self.visit_block(if_block);
4147 self.ribs[ValueNS].pop();
4149 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4152 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4154 ExprKind::While(ref subexpression, ref block, label) => {
4155 self.with_resolved_label(label, expr.id, |this| {
4156 this.visit_expr(subexpression);
4157 this.visit_block(block);
4161 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4162 self.with_resolved_label(label, expr.id, |this| {
4163 this.visit_expr(subexpression);
4164 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4165 let mut bindings_list = FxHashMap::default();
4167 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4169 // This has to happen *after* we determine which pat_idents are variants
4170 this.check_consistent_bindings(pats);
4171 this.visit_block(block);
4172 this.ribs[ValueNS].pop();
4176 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4177 self.visit_expr(subexpression);
4178 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4179 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4181 self.resolve_labeled_block(label, expr.id, block);
4183 self.ribs[ValueNS].pop();
4186 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4188 // Equivalent to `visit::walk_expr` + passing some context to children.
4189 ExprKind::Field(ref subexpression, _) => {
4190 self.resolve_expr(subexpression, Some(expr));
4192 ExprKind::MethodCall(ref segment, ref arguments) => {
4193 let mut arguments = arguments.iter();
4194 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4195 for argument in arguments {
4196 self.resolve_expr(argument, None);
4198 self.visit_path_segment(expr.span, segment);
4201 ExprKind::Call(ref callee, ref arguments) => {
4202 self.resolve_expr(callee, Some(expr));
4203 for argument in arguments {
4204 self.resolve_expr(argument, None);
4207 ExprKind::Type(ref type_expr, _) => {
4208 self.current_type_ascription.push(type_expr.span);
4209 visit::walk_expr(self, expr);
4210 self.current_type_ascription.pop();
4212 // Resolve the body of async exprs inside the async closure to which they desugar
4213 ExprKind::Async(_, async_closure_id, ref block) => {
4214 let rib_kind = ClosureRibKind(async_closure_id);
4215 self.ribs[ValueNS].push(Rib::new(rib_kind));
4216 self.label_ribs.push(Rib::new(rib_kind));
4217 self.visit_block(&block);
4218 self.label_ribs.pop();
4219 self.ribs[ValueNS].pop();
4221 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4222 // resolve the arguments within the proper scopes so that usages of them inside the
4223 // closure are detected as upvars rather than normal closure arg usages.
4225 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4226 ref fn_decl, ref body, _span,
4228 let rib_kind = ClosureRibKind(expr.id);
4229 self.ribs[ValueNS].push(Rib::new(rib_kind));
4230 self.label_ribs.push(Rib::new(rib_kind));
4231 // Resolve arguments:
4232 let mut bindings_list = FxHashMap::default();
4233 for argument in &fn_decl.inputs {
4234 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4235 self.visit_ty(&argument.ty);
4237 // No need to resolve return type-- the outer closure return type is
4238 // FunctionRetTy::Default
4240 // Now resolve the inner closure
4242 let rib_kind = ClosureRibKind(inner_closure_id);
4243 self.ribs[ValueNS].push(Rib::new(rib_kind));
4244 self.label_ribs.push(Rib::new(rib_kind));
4245 // No need to resolve arguments: the inner closure has none.
4246 // Resolve the return type:
4247 visit::walk_fn_ret_ty(self, &fn_decl.output);
4249 self.visit_expr(body);
4250 self.label_ribs.pop();
4251 self.ribs[ValueNS].pop();
4253 self.label_ribs.pop();
4254 self.ribs[ValueNS].pop();
4257 visit::walk_expr(self, expr);
4262 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4264 ExprKind::Field(_, ident) => {
4265 // FIXME(#6890): Even though you can't treat a method like a
4266 // field, we need to add any trait methods we find that match
4267 // the field name so that we can do some nice error reporting
4268 // later on in typeck.
4269 let traits = self.get_traits_containing_item(ident, ValueNS);
4270 self.trait_map.insert(expr.id, traits);
4272 ExprKind::MethodCall(ref segment, ..) => {
4273 debug!("(recording candidate traits for expr) recording traits for {}",
4275 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4276 self.trait_map.insert(expr.id, traits);
4284 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4285 -> Vec<TraitCandidate> {
4286 debug!("(getting traits containing item) looking for '{}'", ident.name);
4288 let mut found_traits = Vec::new();
4289 // Look for the current trait.
4290 if let Some((module, _)) = self.current_trait_ref {
4291 if self.resolve_ident_in_module(
4292 ModuleOrUniformRoot::Module(module),
4298 let def_id = module.def_id().unwrap();
4299 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4303 ident.span = ident.span.modern();
4304 let mut search_module = self.current_module;
4306 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4307 search_module = unwrap_or!(
4308 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4312 if let Some(prelude) = self.prelude {
4313 if !search_module.no_implicit_prelude {
4314 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4321 fn get_traits_in_module_containing_item(&mut self,
4325 found_traits: &mut Vec<TraitCandidate>) {
4326 assert!(ns == TypeNS || ns == ValueNS);
4327 let mut traits = module.traits.borrow_mut();
4328 if traits.is_none() {
4329 let mut collected_traits = Vec::new();
4330 module.for_each_child(|name, ns, binding| {
4331 if ns != TypeNS { return }
4332 if let Def::Trait(_) = binding.def() {
4333 collected_traits.push((name, binding));
4336 *traits = Some(collected_traits.into_boxed_slice());
4339 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4340 let module = binding.module().unwrap();
4341 let mut ident = ident;
4342 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4345 if self.resolve_ident_in_module_unadjusted(
4346 ModuleOrUniformRoot::Module(module),
4353 let import_id = match binding.kind {
4354 NameBindingKind::Import { directive, .. } => {
4355 self.maybe_unused_trait_imports.insert(directive.id);
4356 self.add_to_glob_map(directive.id, trait_name);
4361 let trait_def_id = module.def_id().unwrap();
4362 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4367 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4369 namespace: Namespace,
4370 start_module: &'a ModuleData<'a>,
4372 filter_fn: FilterFn)
4373 -> Vec<ImportSuggestion>
4374 where FilterFn: Fn(Def) -> bool
4376 let mut candidates = Vec::new();
4377 let mut seen_modules = FxHashSet::default();
4378 let not_local_module = crate_name != keywords::Crate.ident();
4379 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4381 while let Some((in_module,
4383 in_module_is_extern)) = worklist.pop() {
4384 self.populate_module_if_necessary(in_module);
4386 // We have to visit module children in deterministic order to avoid
4387 // instabilities in reported imports (#43552).
4388 in_module.for_each_child_stable(|ident, ns, name_binding| {
4389 // avoid imports entirely
4390 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4391 // avoid non-importable candidates as well
4392 if !name_binding.is_importable() { return; }
4394 // collect results based on the filter function
4395 if ident.name == lookup_name && ns == namespace {
4396 if filter_fn(name_binding.def()) {
4398 let mut segms = path_segments.clone();
4399 if self.session.rust_2018() {
4400 // crate-local absolute paths start with `crate::` in edition 2018
4401 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4403 0, ast::PathSegment::from_ident(crate_name)
4407 segms.push(ast::PathSegment::from_ident(ident));
4409 span: name_binding.span,
4412 // the entity is accessible in the following cases:
4413 // 1. if it's defined in the same crate, it's always
4414 // accessible (since private entities can be made public)
4415 // 2. if it's defined in another crate, it's accessible
4416 // only if both the module is public and the entity is
4417 // declared as public (due to pruning, we don't explore
4418 // outside crate private modules => no need to check this)
4419 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4420 candidates.push(ImportSuggestion { path: path });
4425 // collect submodules to explore
4426 if let Some(module) = name_binding.module() {
4428 let mut path_segments = path_segments.clone();
4429 path_segments.push(ast::PathSegment::from_ident(ident));
4431 let is_extern_crate_that_also_appears_in_prelude =
4432 name_binding.is_extern_crate() &&
4433 self.session.rust_2018();
4435 let is_visible_to_user =
4436 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4438 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4439 // add the module to the lookup
4440 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4441 if seen_modules.insert(module.def_id().unwrap()) {
4442 worklist.push((module, path_segments, is_extern));
4452 /// When name resolution fails, this method can be used to look up candidate
4453 /// entities with the expected name. It allows filtering them using the
4454 /// supplied predicate (which should be used to only accept the types of
4455 /// definitions expected e.g. traits). The lookup spans across all crates.
4457 /// NOTE: The method does not look into imports, but this is not a problem,
4458 /// since we report the definitions (thus, the de-aliased imports).
4459 fn lookup_import_candidates<FilterFn>(&mut self,
4461 namespace: Namespace,
4462 filter_fn: FilterFn)
4463 -> Vec<ImportSuggestion>
4464 where FilterFn: Fn(Def) -> bool
4466 let mut suggestions = self.lookup_import_candidates_from_module(
4467 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4469 if self.session.rust_2018() {
4470 let extern_prelude_names = self.extern_prelude.clone();
4471 for &name in extern_prelude_names.iter() {
4472 let ident = Ident::with_empty_ctxt(name);
4473 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(name,
4476 let crate_root = self.get_module(DefId {
4478 index: CRATE_DEF_INDEX,
4480 self.populate_module_if_necessary(&crate_root);
4482 suggestions.extend(self.lookup_import_candidates_from_module(
4483 lookup_name, namespace, crate_root, ident, &filter_fn));
4491 fn find_module(&mut self,
4493 -> Option<(Module<'a>, ImportSuggestion)>
4495 let mut result = None;
4496 let mut seen_modules = FxHashSet::default();
4497 let mut worklist = vec![(self.graph_root, Vec::new())];
4499 while let Some((in_module, path_segments)) = worklist.pop() {
4500 // abort if the module is already found
4501 if result.is_some() { break; }
4503 self.populate_module_if_necessary(in_module);
4505 in_module.for_each_child_stable(|ident, _, name_binding| {
4506 // abort if the module is already found or if name_binding is private external
4507 if result.is_some() || !name_binding.vis.is_visible_locally() {
4510 if let Some(module) = name_binding.module() {
4512 let mut path_segments = path_segments.clone();
4513 path_segments.push(ast::PathSegment::from_ident(ident));
4514 if module.def() == Some(module_def) {
4516 span: name_binding.span,
4517 segments: path_segments,
4519 result = Some((module, ImportSuggestion { path: path }));
4521 // add the module to the lookup
4522 if seen_modules.insert(module.def_id().unwrap()) {
4523 worklist.push((module, path_segments));
4533 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4534 if let Def::Enum(..) = enum_def {} else {
4535 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4538 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4539 self.populate_module_if_necessary(enum_module);
4541 let mut variants = Vec::new();
4542 enum_module.for_each_child_stable(|ident, _, name_binding| {
4543 if let Def::Variant(..) = name_binding.def() {
4544 let mut segms = enum_import_suggestion.path.segments.clone();
4545 segms.push(ast::PathSegment::from_ident(ident));
4546 variants.push(Path {
4547 span: name_binding.span,
4556 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4557 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4558 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4559 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4563 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4565 ast::VisibilityKind::Public => ty::Visibility::Public,
4566 ast::VisibilityKind::Crate(..) => {
4567 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4569 ast::VisibilityKind::Inherited => {
4570 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4572 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4573 // Visibilities are resolved as global by default, add starting root segment.
4574 let segments = path.make_root().iter().chain(path.segments.iter())
4575 .map(|seg| seg.ident)
4576 .collect::<Vec<_>>();
4577 let def = self.smart_resolve_path_fragment(
4582 PathSource::Visibility,
4583 CrateLint::SimplePath(id),
4585 if def == Def::Err {
4586 ty::Visibility::Public
4588 let vis = ty::Visibility::Restricted(def.def_id());
4589 if self.is_accessible(vis) {
4592 self.session.span_err(path.span, "visibilities can only be restricted \
4593 to ancestor modules");
4594 ty::Visibility::Public
4601 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4602 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4605 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4606 vis.is_accessible_from(module.normal_ancestor_id, self)
4609 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4610 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4611 if !ptr::eq(module, old_module) {
4612 span_bug!(binding.span, "parent module is reset for binding");
4617 fn disambiguate_legacy_vs_modern(
4619 legacy: &'a NameBinding<'a>,
4620 modern: &'a NameBinding<'a>,
4622 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4623 // is disambiguated to mitigate regressions from macro modularization.
4624 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4625 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4626 self.binding_parent_modules.get(&PtrKey(modern))) {
4627 (Some(legacy), Some(modern)) =>
4628 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4629 modern.is_ancestor_of(legacy),
4634 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4635 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4637 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4639 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4640 let note = if b1.expansion != Mark::root() {
4641 Some(if let Def::Macro(..) = b1.def() {
4642 format!("macro-expanded {} do not shadow",
4643 if b1.is_import() { "macro imports" } else { "macros" })
4645 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4646 if b1.is_import() { "imports" } else { "items" })
4648 } else if b1.is_glob_import() {
4649 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4654 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4655 err.span_label(ident.span, "ambiguous name");
4656 err.span_note(b1.span, &msg1);
4658 Def::Macro(..) if b2.span.is_dummy() =>
4659 err.note(&format!("`{}` is also a builtin macro", ident)),
4660 _ => err.span_note(b2.span, &msg2),
4662 if let Some(note) = note {
4668 fn report_errors(&mut self, krate: &Crate) {
4669 self.report_with_use_injections(krate);
4670 let mut reported_spans = FxHashSet::default();
4672 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4673 let msg = "macro-expanded `macro_export` macros from the current crate \
4674 cannot be referred to by absolute paths";
4675 self.session.buffer_lint_with_diagnostic(
4676 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4677 CRATE_NODE_ID, span_use, msg,
4678 lint::builtin::BuiltinLintDiagnostics::
4679 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4683 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4684 if reported_spans.insert(ident.span) {
4685 self.report_ambiguity_error(ident, b1, b2);
4689 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4690 if !reported_spans.insert(span) { continue }
4691 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4695 fn report_with_use_injections(&mut self, krate: &Crate) {
4696 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4697 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4698 if !candidates.is_empty() {
4699 show_candidates(&mut err, span, &candidates, better, found_use);
4705 fn report_conflict<'b>(&mut self,
4709 new_binding: &NameBinding<'b>,
4710 old_binding: &NameBinding<'b>) {
4711 // Error on the second of two conflicting names
4712 if old_binding.span.lo() > new_binding.span.lo() {
4713 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4716 let container = match parent.kind {
4717 ModuleKind::Def(Def::Mod(_), _) => "module",
4718 ModuleKind::Def(Def::Trait(_), _) => "trait",
4719 ModuleKind::Block(..) => "block",
4723 let old_noun = match old_binding.is_import() {
4725 false => "definition",
4728 let new_participle = match new_binding.is_import() {
4733 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4735 if let Some(s) = self.name_already_seen.get(&name) {
4741 let old_kind = match (ns, old_binding.module()) {
4742 (ValueNS, _) => "value",
4743 (MacroNS, _) => "macro",
4744 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4745 (TypeNS, Some(module)) if module.is_normal() => "module",
4746 (TypeNS, Some(module)) if module.is_trait() => "trait",
4747 (TypeNS, _) => "type",
4750 let msg = format!("the name `{}` is defined multiple times", name);
4752 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4753 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4754 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4755 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4756 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4758 _ => match (old_binding.is_import(), new_binding.is_import()) {
4759 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4760 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4761 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4765 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4770 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4771 if !old_binding.span.is_dummy() {
4772 err.span_label(self.session.source_map().def_span(old_binding.span),
4773 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4776 // See https://github.com/rust-lang/rust/issues/32354
4777 if old_binding.is_import() || new_binding.is_import() {
4778 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4784 let cm = self.session.source_map();
4785 let rename_msg = "You can use `as` to change the binding name of the import";
4787 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4788 binding.is_renamed_extern_crate()) {
4789 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4790 format!("Other{}", name)
4792 format!("other_{}", name)
4795 err.span_suggestion_with_applicability(
4798 if snippet.ends_with(';') {
4799 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4801 format!("{} as {}", snippet, suggested_name)
4803 Applicability::MachineApplicable,
4806 err.span_label(binding.span, rename_msg);
4811 self.name_already_seen.insert(name, span);
4815 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4816 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4819 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4820 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4823 fn names_to_string(idents: &[Ident]) -> String {
4824 let mut result = String::new();
4825 for (i, ident) in idents.iter()
4826 .filter(|ident| ident.name != keywords::CrateRoot.name())
4829 result.push_str("::");
4831 result.push_str(&ident.as_str());
4836 fn path_names_to_string(path: &Path) -> String {
4837 names_to_string(&path.segments.iter()
4838 .map(|seg| seg.ident)
4839 .collect::<Vec<_>>())
4842 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4843 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4844 let variant_path = &suggestion.path;
4845 let variant_path_string = path_names_to_string(variant_path);
4847 let path_len = suggestion.path.segments.len();
4848 let enum_path = ast::Path {
4849 span: suggestion.path.span,
4850 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4852 let enum_path_string = path_names_to_string(&enum_path);
4854 (suggestion.path.span, variant_path_string, enum_path_string)
4858 /// When an entity with a given name is not available in scope, we search for
4859 /// entities with that name in all crates. This method allows outputting the
4860 /// results of this search in a programmer-friendly way
4861 fn show_candidates(err: &mut DiagnosticBuilder,
4862 // This is `None` if all placement locations are inside expansions
4864 candidates: &[ImportSuggestion],
4868 // we want consistent results across executions, but candidates are produced
4869 // by iterating through a hash map, so make sure they are ordered:
4870 let mut path_strings: Vec<_> =
4871 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4872 path_strings.sort();
4874 let better = if better { "better " } else { "" };
4875 let msg_diff = match path_strings.len() {
4876 1 => " is found in another module, you can import it",
4877 _ => "s are found in other modules, you can import them",
4879 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4881 if let Some(span) = span {
4882 for candidate in &mut path_strings {
4883 // produce an additional newline to separate the new use statement
4884 // from the directly following item.
4885 let additional_newline = if found_use {
4890 *candidate = format!("use {};\n{}", candidate, additional_newline);
4893 err.span_suggestions_with_applicability(
4897 Applicability::Unspecified,
4902 for candidate in path_strings {
4904 msg.push_str(&candidate);
4909 /// A somewhat inefficient routine to obtain the name of a module.
4910 fn module_to_string(module: Module) -> Option<String> {
4911 let mut names = Vec::new();
4913 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4914 if let ModuleKind::Def(_, name) = module.kind {
4915 if let Some(parent) = module.parent {
4916 names.push(Ident::with_empty_ctxt(name));
4917 collect_mod(names, parent);
4920 // danger, shouldn't be ident?
4921 names.push(Ident::from_str("<opaque>"));
4922 collect_mod(names, module.parent.unwrap());
4925 collect_mod(&mut names, module);
4927 if names.is_empty() {
4930 Some(names_to_string(&names.into_iter()
4932 .collect::<Vec<_>>()))
4935 fn err_path_resolution() -> PathResolution {
4936 PathResolution::new(Def::Err)
4939 #[derive(PartialEq,Copy, Clone)]
4940 pub enum MakeGlobMap {
4945 #[derive(Copy, Clone, Debug)]
4947 /// Do not issue the lint
4950 /// This lint applies to some random path like `impl ::foo::Bar`
4951 /// or whatever. In this case, we can take the span of that path.
4954 /// This lint comes from a `use` statement. In this case, what we
4955 /// care about really is the *root* `use` statement; e.g., if we
4956 /// have nested things like `use a::{b, c}`, we care about the
4958 UsePath { root_id: NodeId, root_span: Span },
4960 /// This is the "trait item" from a fully qualified path. For example,
4961 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4962 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4963 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4967 fn node_id(&self) -> Option<NodeId> {
4969 CrateLint::No => None,
4970 CrateLint::SimplePath(id) |
4971 CrateLint::UsePath { root_id: id, .. } |
4972 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4977 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }