1 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
3 #![feature(crate_visibility_modifier)]
4 #![feature(label_break_value)]
6 #![feature(rustc_diagnostic_macros)]
8 #![recursion_limit="256"]
10 #![deny(rust_2018_idioms)]
11 #![cfg_attr(not(stage0), deny(internal))]
13 pub use rustc::hir::def::{Namespace, PerNS};
15 use GenericParameters::*;
18 use rustc::hir::map::{Definitions, DefCollector};
19 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
20 use rustc::middle::cstore::CrateStore;
21 use rustc::session::Session;
23 use rustc::hir::def::*;
24 use rustc::hir::def::Namespace::*;
25 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
26 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
27 use rustc::ty::{self, DefIdTree};
28 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
29 use rustc::{bug, span_bug};
31 use rustc_metadata::creader::CrateLoader;
32 use rustc_metadata::cstore::CStore;
34 use syntax::source_map::SourceMap;
35 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
36 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
37 use syntax::ext::base::SyntaxExtension;
38 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
39 use syntax::ext::base::MacroKind;
40 use syntax::symbol::{Symbol, keywords};
41 use syntax::util::lev_distance::find_best_match_for_name;
43 use syntax::visit::{self, FnKind, Visitor};
45 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
46 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
47 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
48 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
49 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
51 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
53 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
54 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
58 use std::cell::{Cell, RefCell};
59 use std::{cmp, fmt, iter, mem, ptr};
60 use std::collections::BTreeSet;
61 use std::mem::replace;
62 use rustc_data_structures::ptr_key::PtrKey;
63 use rustc_data_structures::sync::Lrc;
65 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
66 use macros::{InvocationData, LegacyBinding, ParentScope};
68 // N.B., this module needs to be declared first so diagnostics are
69 // registered before they are used.
74 mod build_reduced_graph;
77 fn is_known_tool(name: Name) -> bool {
78 ["clippy", "rustfmt"].contains(&&*name.as_str())
88 AbsolutePath(Namespace),
93 /// A free importable items suggested in case of resolution failure.
94 struct ImportSuggestion {
99 /// A field or associated item from self type suggested in case of resolution failure.
100 enum AssocSuggestion {
107 struct BindingError {
109 origin: BTreeSet<Span>,
110 target: BTreeSet<Span>,
113 struct TypoSuggestion {
116 /// The kind of the binding ("crate", "module", etc.)
119 /// An appropriate article to refer to the binding ("a", "an", etc.)
120 article: &'static str,
123 impl PartialOrd for BindingError {
124 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
125 Some(self.cmp(other))
129 impl PartialEq for BindingError {
130 fn eq(&self, other: &BindingError) -> bool {
131 self.name == other.name
135 impl Ord for BindingError {
136 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
137 self.name.cmp(&other.name)
141 /// A span, message, replacement text, and applicability.
142 type Suggestion = (Span, String, String, Applicability);
144 enum ResolutionError<'a> {
145 /// Error E0401: can't use type or const parameters from outer function.
146 GenericParamsFromOuterFunction(Def),
147 /// Error E0403: the name is already used for a type or const parameter in this generic
149 NameAlreadyUsedInParameterList(Name, &'a Span),
150 /// Error E0407: method is not a member of trait.
151 MethodNotMemberOfTrait(Name, &'a str),
152 /// Error E0437: type is not a member of trait.
153 TypeNotMemberOfTrait(Name, &'a str),
154 /// Error E0438: const is not a member of trait.
155 ConstNotMemberOfTrait(Name, &'a str),
156 /// Error E0408: variable `{}` is not bound in all patterns.
157 VariableNotBoundInPattern(&'a BindingError),
158 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
159 VariableBoundWithDifferentMode(Name, Span),
160 /// Error E0415: identifier is bound more than once in this parameter list.
161 IdentifierBoundMoreThanOnceInParameterList(&'a str),
162 /// Error E0416: identifier is bound more than once in the same pattern.
163 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
164 /// Error E0426: use of undeclared label.
165 UndeclaredLabel(&'a str, Option<Name>),
166 /// Error E0429: `self` imports are only allowed within a `{ }` list.
167 SelfImportsOnlyAllowedWithin,
168 /// Error E0430: `self` import can only appear once in the list.
169 SelfImportCanOnlyAppearOnceInTheList,
170 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
171 SelfImportOnlyInImportListWithNonEmptyPrefix,
172 /// Error E0433: failed to resolve.
173 FailedToResolve { label: String, suggestion: Option<Suggestion> },
174 /// Error E0434: can't capture dynamic environment in a fn item.
175 CannotCaptureDynamicEnvironmentInFnItem,
176 /// Error E0435: attempt to use a non-constant value in a constant.
177 AttemptToUseNonConstantValueInConstant,
178 /// Error E0530: `X` bindings cannot shadow `Y`s.
179 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
180 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
181 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
184 /// Combines an error with provided span and emits it.
186 /// This takes the error provided, combines it with the span and any additional spans inside the
187 /// error and emits it.
188 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
190 resolution_error: ResolutionError<'a>) {
191 resolve_struct_error(resolver, span, resolution_error).emit();
194 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
196 resolution_error: ResolutionError<'a>)
197 -> DiagnosticBuilder<'sess> {
198 match resolution_error {
199 ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
200 let mut err = struct_span_err!(resolver.session,
203 "can't use generic parameters from outer function",
205 err.span_label(span, format!("use of generic parameter from outer function"));
207 let cm = resolver.session.source_map();
209 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
210 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
211 resolver.definitions.opt_span(def_id)
214 reduce_impl_span_to_impl_keyword(cm, impl_span),
215 "`Self` type implicitly declared here, by this `impl`",
218 match (maybe_trait_defid, maybe_impl_defid) {
220 err.span_label(span, "can't use `Self` here");
223 err.span_label(span, "use a type here instead");
225 (None, None) => bug!("`impl` without trait nor type?"),
229 Def::TyParam(def_id) => {
230 if let Some(span) = resolver.definitions.opt_span(def_id) {
231 err.span_label(span, "type variable from outer function");
234 Def::ConstParam(def_id) => {
235 if let Some(span) = resolver.definitions.opt_span(def_id) {
236 err.span_label(span, "const variable from outer function");
240 bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
245 // Try to retrieve the span of the function signature and generate a new message with
246 // a local type or const parameter.
247 let sugg_msg = &format!("try using a local generic parameter instead");
248 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
249 // Suggest the modification to the user
254 Applicability::MachineApplicable,
256 } else if let Some(sp) = cm.generate_fn_name_span(span) {
258 format!("try adding a local generic parameter in this method instead"));
260 err.help(&format!("try using a local generic parameter instead"));
265 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
266 let mut err = struct_span_err!(resolver.session,
269 "the name `{}` is already used for a generic \
270 parameter in this list of generic parameters",
272 err.span_label(span, "already used");
273 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
276 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
277 let mut err = struct_span_err!(resolver.session,
280 "method `{}` is not a member of trait `{}`",
283 err.span_label(span, format!("not a member of trait `{}`", trait_));
286 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
287 let mut err = struct_span_err!(resolver.session,
290 "type `{}` is not a member of trait `{}`",
293 err.span_label(span, format!("not a member of trait `{}`", trait_));
296 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
297 let mut err = struct_span_err!(resolver.session,
300 "const `{}` is not a member of trait `{}`",
303 err.span_label(span, format!("not a member of trait `{}`", trait_));
306 ResolutionError::VariableNotBoundInPattern(binding_error) => {
307 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
308 let msp = MultiSpan::from_spans(target_sp.clone());
309 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
310 let mut err = resolver.session.struct_span_err_with_code(
313 DiagnosticId::Error("E0408".into()),
315 for sp in target_sp {
316 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
318 let origin_sp = binding_error.origin.iter().cloned();
319 for sp in origin_sp {
320 err.span_label(sp, "variable not in all patterns");
324 ResolutionError::VariableBoundWithDifferentMode(variable_name,
325 first_binding_span) => {
326 let mut err = struct_span_err!(resolver.session,
329 "variable `{}` is bound in inconsistent \
330 ways within the same match arm",
332 err.span_label(span, "bound in different ways");
333 err.span_label(first_binding_span, "first binding");
336 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
337 let mut err = struct_span_err!(resolver.session,
340 "identifier `{}` is bound more than once in this parameter list",
342 err.span_label(span, "used as parameter more than once");
345 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
346 let mut err = struct_span_err!(resolver.session,
349 "identifier `{}` is bound more than once in the same pattern",
351 err.span_label(span, "used in a pattern more than once");
354 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
355 let mut err = struct_span_err!(resolver.session,
358 "use of undeclared label `{}`",
360 if let Some(lev_candidate) = lev_candidate {
361 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
363 err.span_label(span, format!("undeclared label `{}`", name));
367 ResolutionError::SelfImportsOnlyAllowedWithin => {
368 struct_span_err!(resolver.session,
372 "`self` imports are only allowed within a { } list")
374 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
375 let mut err = struct_span_err!(resolver.session, span, E0430,
376 "`self` import can only appear once in an import list");
377 err.span_label(span, "can only appear once in an import list");
380 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
381 let mut err = struct_span_err!(resolver.session, span, E0431,
382 "`self` import can only appear in an import list with \
383 a non-empty prefix");
384 err.span_label(span, "can only appear in an import list with a non-empty prefix");
387 ResolutionError::FailedToResolve { label, suggestion } => {
388 let mut err = struct_span_err!(resolver.session, span, E0433,
389 "failed to resolve: {}", &label);
390 err.span_label(span, label);
392 if let Some((span, msg, suggestion, applicability)) = suggestion {
393 err.span_suggestion(span, &msg, suggestion, applicability);
398 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
399 let mut err = struct_span_err!(resolver.session,
403 "can't capture dynamic environment in a fn item");
404 err.help("use the `|| { ... }` closure form instead");
407 ResolutionError::AttemptToUseNonConstantValueInConstant => {
408 let mut err = struct_span_err!(resolver.session, span, E0435,
409 "attempt to use a non-constant value in a constant");
410 err.span_label(span, "non-constant value");
413 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
414 let shadows_what = binding.descr();
415 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
416 what_binding, shadows_what);
417 err.span_label(span, format!("cannot be named the same as {} {}",
418 binding.article(), shadows_what));
419 let participle = if binding.is_import() { "imported" } else { "defined" };
420 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
421 err.span_label(binding.span, msg);
424 ResolutionError::ForwardDeclaredTyParam => {
425 let mut err = struct_span_err!(resolver.session, span, E0128,
426 "type parameters with a default cannot use \
427 forward declared identifiers");
429 span, "defaulted type parameters cannot be forward declared".to_string());
435 /// Adjust the impl span so that just the `impl` keyword is taken by removing
436 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
437 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
439 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
440 /// parser. If you need to use this function or something similar, please consider updating the
441 /// `source_map` functions and this function to something more robust.
442 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
443 let impl_span = cm.span_until_char(impl_span, '<');
444 let impl_span = cm.span_until_whitespace(impl_span);
448 #[derive(Copy, Clone, Debug)]
451 binding_mode: BindingMode,
454 /// Map from the name in a pattern to its binding mode.
455 type BindingMap = FxHashMap<Ident, BindingInfo>;
457 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
468 fn descr(self) -> &'static str {
470 PatternSource::Match => "match binding",
471 PatternSource::IfLet => "if let binding",
472 PatternSource::WhileLet => "while let binding",
473 PatternSource::Let => "let binding",
474 PatternSource::For => "for binding",
475 PatternSource::FnParam => "function parameter",
480 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
481 enum AliasPossibility {
486 #[derive(Copy, Clone, Debug)]
487 enum PathSource<'a> {
488 // Type paths `Path`.
490 // Trait paths in bounds or impls.
491 Trait(AliasPossibility),
492 // Expression paths `path`, with optional parent context.
493 Expr(Option<&'a Expr>),
494 // Paths in path patterns `Path`.
496 // Paths in struct expressions and patterns `Path { .. }`.
498 // Paths in tuple struct patterns `Path(..)`.
500 // `m::A::B` in `<T as m::A>::B::C`.
501 TraitItem(Namespace),
502 // Path in `pub(path)`
506 impl<'a> PathSource<'a> {
507 fn namespace(self) -> Namespace {
509 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
510 PathSource::Visibility => TypeNS,
511 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
512 PathSource::TraitItem(ns) => ns,
516 fn global_by_default(self) -> bool {
518 PathSource::Visibility => true,
519 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
520 PathSource::Struct | PathSource::TupleStruct |
521 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
525 fn defer_to_typeck(self) -> bool {
527 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
528 PathSource::Struct | PathSource::TupleStruct => true,
529 PathSource::Trait(_) | PathSource::TraitItem(..) |
530 PathSource::Visibility => false,
534 fn descr_expected(self) -> &'static str {
536 PathSource::Type => "type",
537 PathSource::Trait(_) => "trait",
538 PathSource::Pat => "unit struct/variant or constant",
539 PathSource::Struct => "struct, variant or union type",
540 PathSource::TupleStruct => "tuple struct/variant",
541 PathSource::Visibility => "module",
542 PathSource::TraitItem(ns) => match ns {
543 TypeNS => "associated type",
544 ValueNS => "method or associated constant",
545 MacroNS => bug!("associated macro"),
547 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
548 // "function" here means "anything callable" rather than `Def::Fn`,
549 // this is not precise but usually more helpful than just "value".
550 Some(&ExprKind::Call(..)) => "function",
556 fn is_expected(self, def: Def) -> bool {
558 PathSource::Type => match def {
559 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
560 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
561 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
562 Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
565 PathSource::Trait(AliasPossibility::No) => match def {
566 Def::Trait(..) => true,
569 PathSource::Trait(AliasPossibility::Maybe) => match def {
570 Def::Trait(..) => true,
571 Def::TraitAlias(..) => true,
574 PathSource::Expr(..) => match def {
575 Def::Ctor(_, _, CtorKind::Const) | Def::Ctor(_, _, CtorKind::Fn) |
576 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
577 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
578 Def::SelfCtor(..) | Def::ConstParam(..) => true,
581 PathSource::Pat => match def {
582 Def::Ctor(_, _, CtorKind::Const) |
583 Def::Const(..) | Def::AssociatedConst(..) |
584 Def::SelfCtor(..) => true,
587 PathSource::TupleStruct => match def {
588 Def::Ctor(_, _, CtorKind::Fn) | Def::SelfCtor(..) => true,
591 PathSource::Struct => match def {
592 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
593 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
596 PathSource::TraitItem(ns) => match def {
597 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
598 Def::AssociatedTy(..) if ns == TypeNS => true,
601 PathSource::Visibility => match def {
602 Def::Mod(..) => true,
608 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
609 __diagnostic_used!(E0404);
610 __diagnostic_used!(E0405);
611 __diagnostic_used!(E0412);
612 __diagnostic_used!(E0422);
613 __diagnostic_used!(E0423);
614 __diagnostic_used!(E0425);
615 __diagnostic_used!(E0531);
616 __diagnostic_used!(E0532);
617 __diagnostic_used!(E0573);
618 __diagnostic_used!(E0574);
619 __diagnostic_used!(E0575);
620 __diagnostic_used!(E0576);
621 __diagnostic_used!(E0577);
622 __diagnostic_used!(E0578);
623 match (self, has_unexpected_resolution) {
624 (PathSource::Trait(_), true) => "E0404",
625 (PathSource::Trait(_), false) => "E0405",
626 (PathSource::Type, true) => "E0573",
627 (PathSource::Type, false) => "E0412",
628 (PathSource::Struct, true) => "E0574",
629 (PathSource::Struct, false) => "E0422",
630 (PathSource::Expr(..), true) => "E0423",
631 (PathSource::Expr(..), false) => "E0425",
632 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
633 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
634 (PathSource::TraitItem(..), true) => "E0575",
635 (PathSource::TraitItem(..), false) => "E0576",
636 (PathSource::Visibility, true) => "E0577",
637 (PathSource::Visibility, false) => "E0578",
642 // A minimal representation of a path segment. We use this in resolve because
643 // we synthesize 'path segments' which don't have the rest of an AST or HIR
645 #[derive(Clone, Copy, Debug)]
652 fn from_path(path: &Path) -> Vec<Segment> {
653 path.segments.iter().map(|s| s.into()).collect()
656 fn from_ident(ident: Ident) -> Segment {
663 fn names_to_string(segments: &[Segment]) -> String {
664 names_to_string(&segments.iter()
665 .map(|seg| seg.ident)
666 .collect::<Vec<_>>())
670 impl<'a> From<&'a ast::PathSegment> for Segment {
671 fn from(seg: &'a ast::PathSegment) -> Segment {
679 struct UsePlacementFinder {
680 target_module: NodeId,
685 impl UsePlacementFinder {
686 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
687 let mut finder = UsePlacementFinder {
692 visit::walk_crate(&mut finder, krate);
693 (finder.span, finder.found_use)
697 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
700 module: &'tcx ast::Mod,
702 _: &[ast::Attribute],
705 if self.span.is_some() {
708 if node_id != self.target_module {
709 visit::walk_mod(self, module);
712 // find a use statement
713 for item in &module.items {
715 ItemKind::Use(..) => {
716 // don't suggest placing a use before the prelude
717 // import or other generated ones
718 if item.span.ctxt().outer().expn_info().is_none() {
719 self.span = Some(item.span.shrink_to_lo());
720 self.found_use = true;
724 // don't place use before extern crate
725 ItemKind::ExternCrate(_) => {}
726 // but place them before the first other item
727 _ => if self.span.map_or(true, |span| item.span < span ) {
728 if item.span.ctxt().outer().expn_info().is_none() {
729 // don't insert between attributes and an item
730 if item.attrs.is_empty() {
731 self.span = Some(item.span.shrink_to_lo());
733 // find the first attribute on the item
734 for attr in &item.attrs {
735 if self.span.map_or(true, |span| attr.span < span) {
736 self.span = Some(attr.span.shrink_to_lo());
747 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
748 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
749 fn visit_item(&mut self, item: &'tcx Item) {
750 self.resolve_item(item);
752 fn visit_arm(&mut self, arm: &'tcx Arm) {
753 self.resolve_arm(arm);
755 fn visit_block(&mut self, block: &'tcx Block) {
756 self.resolve_block(block);
758 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
759 debug!("visit_anon_const {:?}", constant);
760 self.with_constant_rib(|this| {
761 visit::walk_anon_const(this, constant);
764 fn visit_expr(&mut self, expr: &'tcx Expr) {
765 self.resolve_expr(expr, None);
767 fn visit_local(&mut self, local: &'tcx Local) {
768 self.resolve_local(local);
770 fn visit_ty(&mut self, ty: &'tcx Ty) {
772 TyKind::Path(ref qself, ref path) => {
773 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
775 TyKind::ImplicitSelf => {
776 let self_ty = keywords::SelfUpper.ident();
777 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
778 .map_or(Def::Err, |d| d.def());
779 self.record_def(ty.id, PathResolution::new(def));
783 visit::walk_ty(self, ty);
785 fn visit_poly_trait_ref(&mut self,
786 tref: &'tcx ast::PolyTraitRef,
787 m: &'tcx ast::TraitBoundModifier) {
788 self.smart_resolve_path(tref.trait_ref.ref_id, None,
789 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
790 visit::walk_poly_trait_ref(self, tref, m);
792 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
793 let generic_params = match foreign_item.node {
794 ForeignItemKind::Fn(_, ref generics) => {
795 HasGenericParams(generics, ItemRibKind)
797 ForeignItemKind::Static(..) => NoGenericParams,
798 ForeignItemKind::Ty => NoGenericParams,
799 ForeignItemKind::Macro(..) => NoGenericParams,
801 self.with_generic_param_rib(generic_params, |this| {
802 visit::walk_foreign_item(this, foreign_item);
805 fn visit_fn(&mut self,
806 function_kind: FnKind<'tcx>,
807 declaration: &'tcx FnDecl,
811 debug!("(resolving function) entering function");
812 let (rib_kind, asyncness) = match function_kind {
813 FnKind::ItemFn(_, ref header, ..) =>
814 (FnItemRibKind, header.asyncness.node),
815 FnKind::Method(_, ref sig, _, _) =>
816 (TraitOrImplItemRibKind, sig.header.asyncness.node),
817 FnKind::Closure(_) =>
818 // Async closures aren't resolved through `visit_fn`-- they're
819 // processed separately
820 (ClosureRibKind(node_id), IsAsync::NotAsync),
823 // Create a value rib for the function.
824 self.ribs[ValueNS].push(Rib::new(rib_kind));
826 // Create a label rib for the function.
827 self.label_ribs.push(Rib::new(rib_kind));
829 // Add each argument to the rib.
830 let mut bindings_list = FxHashMap::default();
831 for argument in &declaration.inputs {
832 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
834 self.visit_ty(&argument.ty);
836 debug!("(resolving function) recorded argument");
838 visit::walk_fn_ret_ty(self, &declaration.output);
840 // Resolve the function body, potentially inside the body of an async closure
841 if let IsAsync::Async { closure_id, .. } = asyncness {
842 let rib_kind = ClosureRibKind(closure_id);
843 self.ribs[ValueNS].push(Rib::new(rib_kind));
844 self.label_ribs.push(Rib::new(rib_kind));
847 match function_kind {
848 FnKind::ItemFn(.., body) |
849 FnKind::Method(.., body) => {
850 self.visit_block(body);
852 FnKind::Closure(body) => {
853 self.visit_expr(body);
857 // Leave the body of the async closure
858 if asyncness.is_async() {
859 self.label_ribs.pop();
860 self.ribs[ValueNS].pop();
863 debug!("(resolving function) leaving function");
865 self.label_ribs.pop();
866 self.ribs[ValueNS].pop();
869 fn visit_generics(&mut self, generics: &'tcx Generics) {
870 // For type parameter defaults, we have to ban access
871 // to following type parameters, as the InternalSubsts can only
872 // provide previous type parameters as they're built. We
873 // put all the parameters on the ban list and then remove
874 // them one by one as they are processed and become available.
875 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
876 let mut found_default = false;
877 default_ban_rib.bindings.extend(generics.params.iter()
878 .filter_map(|param| match param.kind {
879 GenericParamKind::Const { .. } |
880 GenericParamKind::Lifetime { .. } => None,
881 GenericParamKind::Type { ref default, .. } => {
882 found_default |= default.is_some();
884 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
891 for param in &generics.params {
893 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
894 GenericParamKind::Type { ref default, .. } => {
895 for bound in ¶m.bounds {
896 self.visit_param_bound(bound);
899 if let Some(ref ty) = default {
900 self.ribs[TypeNS].push(default_ban_rib);
902 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
905 // Allow all following defaults to refer to this type parameter.
906 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
908 GenericParamKind::Const { ref ty } => {
909 for bound in ¶m.bounds {
910 self.visit_param_bound(bound);
917 for p in &generics.where_clause.predicates {
918 self.visit_where_predicate(p);
923 #[derive(Copy, Clone)]
924 enum GenericParameters<'a, 'b> {
926 HasGenericParams(// Type parameters.
929 // The kind of the rib used for type parameters.
933 /// The rib kind controls the translation of local
934 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
935 #[derive(Copy, Clone, Debug)]
937 /// No translation needs to be applied.
940 /// We passed through a closure scope at the given `NodeId`.
941 /// Translate upvars as appropriate.
942 ClosureRibKind(NodeId /* func id */),
944 /// We passed through an impl or trait and are now in one of its
945 /// methods or associated types. Allow references to ty params that impl or trait
946 /// binds. Disallow any other upvars (including other ty params that are
948 TraitOrImplItemRibKind,
950 /// We passed through a function definition. Disallow upvars.
951 /// Permit only those const parameters that are specified in the function's generics.
954 /// We passed through an item scope. Disallow upvars.
957 /// We're in a constant item. Can't refer to dynamic stuff.
960 /// We passed through a module.
961 ModuleRibKind(Module<'a>),
963 /// We passed through a `macro_rules!` statement
964 MacroDefinition(DefId),
966 /// All bindings in this rib are type parameters that can't be used
967 /// from the default of a type parameter because they're not declared
968 /// before said type parameter. Also see the `visit_generics` override.
969 ForwardTyParamBanRibKind,
972 /// A single local scope.
974 /// A rib represents a scope names can live in. Note that these appear in many places, not just
975 /// around braces. At any place where the list of accessible names (of the given namespace)
976 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
977 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
980 /// Different [rib kinds](enum.RibKind) are transparent for different names.
982 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
983 /// resolving, the name is looked up from inside out.
986 bindings: FxHashMap<Ident, Def>,
991 fn new(kind: RibKind<'a>) -> Rib<'a> {
993 bindings: Default::default(),
999 /// An intermediate resolution result.
1001 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
1002 /// items are visible in their whole block, while defs only from the place they are defined
1004 enum LexicalScopeBinding<'a> {
1005 Item(&'a NameBinding<'a>),
1009 impl<'a> LexicalScopeBinding<'a> {
1010 fn item(self) -> Option<&'a NameBinding<'a>> {
1012 LexicalScopeBinding::Item(binding) => Some(binding),
1017 fn def(self) -> Def {
1019 LexicalScopeBinding::Item(binding) => binding.def(),
1020 LexicalScopeBinding::Def(def) => def,
1025 #[derive(Copy, Clone, Debug)]
1026 enum ModuleOrUniformRoot<'a> {
1030 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1031 CrateRootAndExternPrelude,
1033 /// Virtual module that denotes resolution in extern prelude.
1034 /// Used for paths starting with `::` on 2018 edition.
1037 /// Virtual module that denotes resolution in current scope.
1038 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1039 /// are always split into two parts, the first of which should be some kind of module.
1043 impl ModuleOrUniformRoot<'_> {
1044 fn same_def(lhs: Self, rhs: Self) -> bool {
1046 (ModuleOrUniformRoot::Module(lhs),
1047 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1048 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1049 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1050 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1051 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1057 #[derive(Clone, Debug)]
1058 enum PathResult<'a> {
1059 Module(ModuleOrUniformRoot<'a>),
1060 NonModule(PathResolution),
1065 suggestion: Option<Suggestion>,
1066 is_error_from_last_segment: bool,
1071 /// An anonymous module; e.g., just a block.
1075 /// fn f() {} // (1)
1076 /// { // This is an anonymous module
1077 /// f(); // This resolves to (2) as we are inside the block.
1078 /// fn f() {} // (2)
1080 /// f(); // Resolves to (1)
1084 /// Any module with a name.
1088 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1089 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1094 /// One node in the tree of modules.
1095 pub struct ModuleData<'a> {
1096 parent: Option<Module<'a>>,
1099 // The def id of the closest normal module (`mod`) ancestor (including this module).
1100 normal_ancestor_id: DefId,
1102 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1103 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1104 Option<&'a NameBinding<'a>>)>>,
1105 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1107 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1109 // Macro invocations that can expand into items in this module.
1110 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1112 no_implicit_prelude: bool,
1114 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1115 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1117 // Used to memoize the traits in this module for faster searches through all traits in scope.
1118 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1120 // Whether this module is populated. If not populated, any attempt to
1121 // access the children must be preceded with a
1122 // `populate_module_if_necessary` call.
1123 populated: Cell<bool>,
1125 /// Span of the module itself. Used for error reporting.
1131 type Module<'a> = &'a ModuleData<'a>;
1133 impl<'a> ModuleData<'a> {
1134 fn new(parent: Option<Module<'a>>,
1136 normal_ancestor_id: DefId,
1138 span: Span) -> Self {
1143 resolutions: Default::default(),
1144 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1145 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1146 builtin_attrs: RefCell::new(Vec::new()),
1147 unresolved_invocations: Default::default(),
1148 no_implicit_prelude: false,
1149 glob_importers: RefCell::new(Vec::new()),
1150 globs: RefCell::new(Vec::new()),
1151 traits: RefCell::new(None),
1152 populated: Cell::new(normal_ancestor_id.is_local()),
1158 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1159 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1160 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1164 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1165 let resolutions = self.resolutions.borrow();
1166 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1167 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1168 for &(&(ident, ns), &resolution) in resolutions.iter() {
1169 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1173 fn def(&self) -> Option<Def> {
1175 ModuleKind::Def(def, _) => Some(def),
1180 fn def_id(&self) -> Option<DefId> {
1181 self.def().as_ref().map(Def::def_id)
1184 // `self` resolves to the first module ancestor that `is_normal`.
1185 fn is_normal(&self) -> bool {
1187 ModuleKind::Def(Def::Mod(_), _) => true,
1192 fn is_trait(&self) -> bool {
1194 ModuleKind::Def(Def::Trait(_), _) => true,
1199 fn nearest_item_scope(&'a self) -> Module<'a> {
1200 if self.is_trait() { self.parent.unwrap() } else { self }
1203 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1204 while !ptr::eq(self, other) {
1205 if let Some(parent) = other.parent {
1215 impl<'a> fmt::Debug for ModuleData<'a> {
1216 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1217 write!(f, "{:?}", self.def())
1221 /// Records a possibly-private value, type, or module definition.
1222 #[derive(Clone, Debug)]
1223 pub struct NameBinding<'a> {
1224 kind: NameBindingKind<'a>,
1225 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1228 vis: ty::Visibility,
1231 pub trait ToNameBinding<'a> {
1232 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1235 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1236 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1241 #[derive(Clone, Debug)]
1242 enum NameBindingKind<'a> {
1243 Def(Def, /* is_macro_export */ bool),
1246 binding: &'a NameBinding<'a>,
1247 directive: &'a ImportDirective<'a>,
1252 impl<'a> NameBindingKind<'a> {
1253 /// Is this a name binding of a import?
1254 fn is_import(&self) -> bool {
1256 NameBindingKind::Import { .. } => true,
1262 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1264 struct UseError<'a> {
1265 err: DiagnosticBuilder<'a>,
1266 /// Attach `use` statements for these candidates.
1267 candidates: Vec<ImportSuggestion>,
1268 /// The `NodeId` of the module to place the use-statements in.
1270 /// Whether the diagnostic should state that it's "better".
1274 #[derive(Clone, Copy, PartialEq, Debug)]
1275 enum AmbiguityKind {
1279 LegacyHelperVsPrelude,
1284 MoreExpandedVsOuter,
1287 impl AmbiguityKind {
1288 fn descr(self) -> &'static str {
1290 AmbiguityKind::Import =>
1291 "name vs any other name during import resolution",
1292 AmbiguityKind::BuiltinAttr =>
1293 "built-in attribute vs any other name",
1294 AmbiguityKind::DeriveHelper =>
1295 "derive helper attribute vs any other name",
1296 AmbiguityKind::LegacyHelperVsPrelude =>
1297 "legacy plugin helper attribute vs name from prelude",
1298 AmbiguityKind::LegacyVsModern =>
1299 "`macro_rules` vs non-`macro_rules` from other module",
1300 AmbiguityKind::GlobVsOuter =>
1301 "glob import vs any other name from outer scope during import/macro resolution",
1302 AmbiguityKind::GlobVsGlob =>
1303 "glob import vs glob import in the same module",
1304 AmbiguityKind::GlobVsExpanded =>
1305 "glob import vs macro-expanded name in the same \
1306 module during import/macro resolution",
1307 AmbiguityKind::MoreExpandedVsOuter =>
1308 "macro-expanded name vs less macro-expanded name \
1309 from outer scope during import/macro resolution",
1314 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1315 #[derive(Clone, Copy, PartialEq)]
1316 enum AmbiguityErrorMisc {
1323 struct AmbiguityError<'a> {
1324 kind: AmbiguityKind,
1326 b1: &'a NameBinding<'a>,
1327 b2: &'a NameBinding<'a>,
1328 misc1: AmbiguityErrorMisc,
1329 misc2: AmbiguityErrorMisc,
1332 impl<'a> NameBinding<'a> {
1333 fn module(&self) -> Option<Module<'a>> {
1335 NameBindingKind::Module(module) => Some(module),
1336 NameBindingKind::Import { binding, .. } => binding.module(),
1341 fn def(&self) -> Def {
1343 NameBindingKind::Def(def, _) => def,
1344 NameBindingKind::Module(module) => module.def().unwrap(),
1345 NameBindingKind::Import { binding, .. } => binding.def(),
1349 fn is_ambiguity(&self) -> bool {
1350 self.ambiguity.is_some() || match self.kind {
1351 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1356 // We sometimes need to treat variants as `pub` for backwards compatibility.
1357 fn pseudo_vis(&self) -> ty::Visibility {
1358 if self.is_variant() && self.def().def_id().is_local() {
1359 ty::Visibility::Public
1365 fn is_variant(&self) -> bool {
1367 NameBindingKind::Def(Def::Variant(..), _) |
1368 NameBindingKind::Def(Def::Ctor(_, CtorOf::Variant, ..), _) => true,
1373 fn is_extern_crate(&self) -> bool {
1375 NameBindingKind::Import {
1376 directive: &ImportDirective {
1377 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1380 NameBindingKind::Module(
1381 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1382 ) => def_id.index == CRATE_DEF_INDEX,
1387 fn is_import(&self) -> bool {
1389 NameBindingKind::Import { .. } => true,
1394 fn is_glob_import(&self) -> bool {
1396 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1401 fn is_importable(&self) -> bool {
1403 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1408 fn is_macro_def(&self) -> bool {
1410 NameBindingKind::Def(Def::Macro(..), _) => true,
1415 fn macro_kind(&self) -> Option<MacroKind> {
1417 Def::Macro(_, kind) => Some(kind),
1418 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1423 fn descr(&self) -> &'static str {
1424 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1427 fn article(&self) -> &'static str {
1428 if self.is_extern_crate() { "an" } else { self.def().article() }
1431 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1432 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1433 // Then this function returns `true` if `self` may emerge from a macro *after* that
1434 // in some later round and screw up our previously found resolution.
1435 // See more detailed explanation in
1436 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1437 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1438 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1439 // Expansions are partially ordered, so "may appear after" is an inversion of
1440 // "certainly appears before or simultaneously" and includes unordered cases.
1441 let self_parent_expansion = self.expansion;
1442 let other_parent_expansion = binding.expansion;
1443 let certainly_before_other_or_simultaneously =
1444 other_parent_expansion.is_descendant_of(self_parent_expansion);
1445 let certainly_before_invoc_or_simultaneously =
1446 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1447 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1451 /// Interns the names of the primitive types.
1453 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1454 /// special handling, since they have no place of origin.
1456 struct PrimitiveTypeTable {
1457 primitive_types: FxHashMap<Name, PrimTy>,
1460 impl PrimitiveTypeTable {
1461 fn new() -> PrimitiveTypeTable {
1462 let mut table = PrimitiveTypeTable::default();
1464 table.intern("bool", Bool);
1465 table.intern("char", Char);
1466 table.intern("f32", Float(FloatTy::F32));
1467 table.intern("f64", Float(FloatTy::F64));
1468 table.intern("isize", Int(IntTy::Isize));
1469 table.intern("i8", Int(IntTy::I8));
1470 table.intern("i16", Int(IntTy::I16));
1471 table.intern("i32", Int(IntTy::I32));
1472 table.intern("i64", Int(IntTy::I64));
1473 table.intern("i128", Int(IntTy::I128));
1474 table.intern("str", Str);
1475 table.intern("usize", Uint(UintTy::Usize));
1476 table.intern("u8", Uint(UintTy::U8));
1477 table.intern("u16", Uint(UintTy::U16));
1478 table.intern("u32", Uint(UintTy::U32));
1479 table.intern("u64", Uint(UintTy::U64));
1480 table.intern("u128", Uint(UintTy::U128));
1484 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1485 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1489 #[derive(Debug, Default, Clone)]
1490 pub struct ExternPreludeEntry<'a> {
1491 extern_crate_item: Option<&'a NameBinding<'a>>,
1492 pub introduced_by_item: bool,
1495 /// The main resolver class.
1497 /// This is the visitor that walks the whole crate.
1498 pub struct Resolver<'a> {
1499 session: &'a Session,
1502 pub definitions: Definitions,
1504 graph_root: Module<'a>,
1506 prelude: Option<Module<'a>>,
1507 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1509 /// N.B., this is used only for better diagnostics, not name resolution itself.
1510 has_self: FxHashSet<DefId>,
1512 /// Names of fields of an item `DefId` accessible with dot syntax.
1513 /// Used for hints during error reporting.
1514 field_names: FxHashMap<DefId, Vec<Name>>,
1516 /// All imports known to succeed or fail.
1517 determined_imports: Vec<&'a ImportDirective<'a>>,
1519 /// All non-determined imports.
1520 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1522 /// The module that represents the current item scope.
1523 current_module: Module<'a>,
1525 /// The current set of local scopes for types and values.
1526 /// FIXME #4948: Reuse ribs to avoid allocation.
1527 ribs: PerNS<Vec<Rib<'a>>>,
1529 /// The current set of local scopes, for labels.
1530 label_ribs: Vec<Rib<'a>>,
1532 /// The trait that the current context can refer to.
1533 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1535 /// The current self type if inside an impl (used for better errors).
1536 current_self_type: Option<Ty>,
1538 /// The current self item if inside an ADT (used for better errors).
1539 current_self_item: Option<NodeId>,
1541 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1542 /// We are resolving a last import segment during import validation.
1543 last_import_segment: bool,
1544 /// This binding should be ignored during in-module resolution, so that we don't get
1545 /// "self-confirming" import resolutions during import validation.
1546 blacklisted_binding: Option<&'a NameBinding<'a>>,
1548 /// The idents for the primitive types.
1549 primitive_type_table: PrimitiveTypeTable,
1552 import_map: ImportMap,
1553 pub freevars: FreevarMap,
1554 freevars_seen: NodeMap<NodeMap<usize>>,
1555 pub export_map: ExportMap,
1556 pub trait_map: TraitMap,
1558 /// A map from nodes to anonymous modules.
1559 /// Anonymous modules are pseudo-modules that are implicitly created around items
1560 /// contained within blocks.
1562 /// For example, if we have this:
1570 /// There will be an anonymous module created around `g` with the ID of the
1571 /// entry block for `f`.
1572 block_map: NodeMap<Module<'a>>,
1573 module_map: FxHashMap<DefId, Module<'a>>,
1574 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1575 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1577 /// Maps glob imports to the names of items actually imported.
1578 pub glob_map: GlobMap,
1580 used_imports: FxHashSet<(NodeId, Namespace)>,
1581 pub maybe_unused_trait_imports: NodeSet,
1582 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1584 /// A list of labels as of yet unused. Labels will be removed from this map when
1585 /// they are used (in a `break` or `continue` statement)
1586 pub unused_labels: FxHashMap<NodeId, Span>,
1588 /// Privacy errors are delayed until the end in order to deduplicate them.
1589 privacy_errors: Vec<PrivacyError<'a>>,
1590 /// Ambiguity errors are delayed for deduplication.
1591 ambiguity_errors: Vec<AmbiguityError<'a>>,
1592 /// `use` injections are delayed for better placement and deduplication.
1593 use_injections: Vec<UseError<'a>>,
1594 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1595 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1597 arenas: &'a ResolverArenas<'a>,
1598 dummy_binding: &'a NameBinding<'a>,
1600 crate_loader: &'a mut CrateLoader<'a>,
1601 macro_names: FxHashSet<Ident>,
1602 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1603 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1604 pub all_macros: FxHashMap<Name, Def>,
1605 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1606 macro_defs: FxHashMap<Mark, DefId>,
1607 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1609 /// List of crate local macros that we need to warn about as being unused.
1610 /// Right now this only includes macro_rules! macros, and macros 2.0.
1611 unused_macros: FxHashSet<DefId>,
1613 /// Maps the `Mark` of an expansion to its containing module or block.
1614 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1616 /// Avoid duplicated errors for "name already defined".
1617 name_already_seen: FxHashMap<Name, Span>,
1619 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1621 /// Table for mapping struct IDs into struct constructor IDs,
1622 /// it's not used during normal resolution, only for better error reporting.
1623 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1625 /// Only used for better errors on `fn(): fn()`.
1626 current_type_ascription: Vec<Span>,
1628 injected_crate: Option<Module<'a>>,
1631 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1633 pub struct ResolverArenas<'a> {
1634 modules: arena::TypedArena<ModuleData<'a>>,
1635 local_modules: RefCell<Vec<Module<'a>>>,
1636 name_bindings: arena::TypedArena<NameBinding<'a>>,
1637 import_directives: arena::TypedArena<ImportDirective<'a>>,
1638 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1639 invocation_data: arena::TypedArena<InvocationData<'a>>,
1640 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1643 impl<'a> ResolverArenas<'a> {
1644 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1645 let module = self.modules.alloc(module);
1646 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1647 self.local_modules.borrow_mut().push(module);
1651 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1652 self.local_modules.borrow()
1654 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1655 self.name_bindings.alloc(name_binding)
1657 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1658 -> &'a ImportDirective<'_> {
1659 self.import_directives.alloc(import_directive)
1661 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1662 self.name_resolutions.alloc(Default::default())
1664 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1665 -> &'a InvocationData<'a> {
1666 self.invocation_data.alloc(expansion_data)
1668 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1669 self.legacy_bindings.alloc(binding)
1673 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1674 fn parent(self, id: DefId) -> Option<DefId> {
1676 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1677 _ => self.cstore.def_key(id).parent,
1678 }.map(|index| DefId { index, ..id })
1682 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1683 /// the resolver is no longer needed as all the relevant information is inline.
1684 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1685 fn resolve_hir_path(
1690 self.resolve_hir_path_cb(path, is_value,
1691 |resolver, span, error| resolve_error(resolver, span, error))
1694 fn resolve_str_path(
1697 crate_root: Option<&str>,
1698 components: &[&str],
1701 let root = if crate_root.is_some() {
1706 let segments = iter::once(root.ident())
1708 crate_root.into_iter()
1709 .chain(components.iter().cloned())
1710 .map(Ident::from_str)
1711 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1714 let path = ast::Path {
1719 self.resolve_hir_path(&path, is_value)
1722 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1723 self.def_map.get(&id).cloned()
1726 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1727 self.import_map.get(&id).cloned().unwrap_or_default()
1730 fn definitions(&mut self) -> &mut Definitions {
1731 &mut self.definitions
1735 impl<'a> Resolver<'a> {
1736 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1737 /// isn't something that can be returned because it can't be made to live that long,
1738 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1739 /// just that an error occurred.
1740 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1741 -> Result<hir::Path, ()> {
1742 let mut errored = false;
1744 let path = if path_str.starts_with("::") {
1747 segments: iter::once(keywords::PathRoot.ident())
1749 path_str.split("::").skip(1).map(Ident::from_str)
1751 .map(|i| self.new_ast_path_segment(i))
1759 .map(Ident::from_str)
1760 .map(|i| self.new_ast_path_segment(i))
1764 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1765 if errored || path.def == Def::Err {
1772 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1773 fn resolve_hir_path_cb<F>(
1779 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1781 let namespace = if is_value { ValueNS } else { TypeNS };
1782 let span = path.span;
1783 let segments = &path.segments;
1784 let path = Segment::from_path(&path);
1785 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1786 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1787 span, CrateLint::No) {
1788 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1789 module.def().unwrap(),
1790 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1791 path_res.base_def(),
1792 PathResult::NonModule(..) => {
1793 error_callback(self, span, ResolutionError::FailedToResolve {
1794 label: String::from("type-relative paths are not supported in this context"),
1799 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1800 PathResult::Failed { span, label, suggestion, .. } => {
1801 error_callback(self, span, ResolutionError::FailedToResolve {
1809 let segments: Vec<_> = segments.iter().map(|seg| {
1810 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1811 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1817 segments: segments.into(),
1821 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1822 let mut seg = ast::PathSegment::from_ident(ident);
1823 seg.id = self.session.next_node_id();
1828 impl<'a> Resolver<'a> {
1829 pub fn new(session: &'a Session,
1833 crate_loader: &'a mut CrateLoader<'a>,
1834 arenas: &'a ResolverArenas<'a>)
1836 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1837 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1838 let graph_root = arenas.alloc_module(ModuleData {
1839 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1840 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1842 let mut module_map = FxHashMap::default();
1843 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1845 let mut definitions = Definitions::new();
1846 DefCollector::new(&mut definitions, Mark::root())
1847 .collect_root(crate_name, session.local_crate_disambiguator());
1849 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1850 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1853 if !attr::contains_name(&krate.attrs, "no_core") {
1854 extern_prelude.insert(Ident::from_str("core"), Default::default());
1855 if !attr::contains_name(&krate.attrs, "no_std") {
1856 extern_prelude.insert(Ident::from_str("std"), Default::default());
1857 if session.rust_2018() {
1858 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1863 let mut invocations = FxHashMap::default();
1864 invocations.insert(Mark::root(),
1865 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1867 let mut macro_defs = FxHashMap::default();
1868 macro_defs.insert(Mark::root(), root_def_id);
1877 // The outermost module has def ID 0; this is not reflected in the
1883 has_self: FxHashSet::default(),
1884 field_names: FxHashMap::default(),
1886 determined_imports: Vec::new(),
1887 indeterminate_imports: Vec::new(),
1889 current_module: graph_root,
1891 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1892 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1893 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1895 label_ribs: Vec::new(),
1897 current_trait_ref: None,
1898 current_self_type: None,
1899 current_self_item: None,
1900 last_import_segment: false,
1901 blacklisted_binding: None,
1903 primitive_type_table: PrimitiveTypeTable::new(),
1905 def_map: Default::default(),
1906 import_map: Default::default(),
1907 freevars: Default::default(),
1908 freevars_seen: Default::default(),
1909 export_map: FxHashMap::default(),
1910 trait_map: Default::default(),
1912 block_map: Default::default(),
1913 extern_module_map: FxHashMap::default(),
1914 binding_parent_modules: FxHashMap::default(),
1916 glob_map: Default::default(),
1918 used_imports: FxHashSet::default(),
1919 maybe_unused_trait_imports: Default::default(),
1920 maybe_unused_extern_crates: Vec::new(),
1922 unused_labels: FxHashMap::default(),
1924 privacy_errors: Vec::new(),
1925 ambiguity_errors: Vec::new(),
1926 use_injections: Vec::new(),
1927 macro_expanded_macro_export_errors: BTreeSet::new(),
1930 dummy_binding: arenas.alloc_name_binding(NameBinding {
1931 kind: NameBindingKind::Def(Def::Err, false),
1933 expansion: Mark::root(),
1935 vis: ty::Visibility::Public,
1939 macro_names: FxHashSet::default(),
1940 builtin_macros: FxHashMap::default(),
1941 macro_use_prelude: FxHashMap::default(),
1942 all_macros: FxHashMap::default(),
1943 macro_map: FxHashMap::default(),
1946 local_macro_def_scopes: FxHashMap::default(),
1947 name_already_seen: FxHashMap::default(),
1948 potentially_unused_imports: Vec::new(),
1949 struct_constructors: Default::default(),
1950 unused_macros: FxHashSet::default(),
1951 current_type_ascription: Vec::new(),
1952 injected_crate: None,
1956 pub fn arenas() -> ResolverArenas<'a> {
1960 /// Runs the function on each namespace.
1961 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1967 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1969 match self.macro_defs.get(&ctxt.outer()) {
1970 Some(&def_id) => return def_id,
1971 None => ctxt.remove_mark(),
1976 /// Entry point to crate resolution.
1977 pub fn resolve_crate(&mut self, krate: &Crate) {
1978 ImportResolver { resolver: self }.finalize_imports();
1979 self.current_module = self.graph_root;
1980 self.finalize_current_module_macro_resolutions();
1982 visit::walk_crate(self, krate);
1984 check_unused::check_crate(self, krate);
1985 self.report_errors(krate);
1986 self.crate_loader.postprocess(krate);
1993 normal_ancestor_id: DefId,
1997 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1998 self.arenas.alloc_module(module)
2001 fn record_use(&mut self, ident: Ident, ns: Namespace,
2002 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
2003 if let Some((b2, kind)) = used_binding.ambiguity {
2004 self.ambiguity_errors.push(AmbiguityError {
2005 kind, ident, b1: used_binding, b2,
2006 misc1: AmbiguityErrorMisc::None,
2007 misc2: AmbiguityErrorMisc::None,
2010 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
2011 // Avoid marking `extern crate` items that refer to a name from extern prelude,
2012 // but not introduce it, as used if they are accessed from lexical scope.
2013 if is_lexical_scope {
2014 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
2015 if let Some(crate_item) = entry.extern_crate_item {
2016 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2023 directive.used.set(true);
2024 self.used_imports.insert((directive.id, ns));
2025 self.add_to_glob_map(&directive, ident);
2026 self.record_use(ident, ns, binding, false);
2031 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2032 if directive.is_glob() {
2033 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2037 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2038 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2039 /// `ident` in the first scope that defines it (or None if no scopes define it).
2041 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2042 /// the items are defined in the block. For example,
2045 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2048 /// g(); // This resolves to the local variable `g` since it shadows the item.
2052 /// Invariant: This must only be called during main resolution, not during
2053 /// import resolution.
2054 fn resolve_ident_in_lexical_scope(&mut self,
2057 record_used_id: Option<NodeId>,
2059 -> Option<LexicalScopeBinding<'a>> {
2060 assert!(ns == TypeNS || ns == ValueNS);
2061 if ident.name == keywords::Invalid.name() {
2062 return Some(LexicalScopeBinding::Def(Def::Err));
2064 ident.span = if ident.name == keywords::SelfUpper.name() {
2065 // FIXME(jseyfried) improve `Self` hygiene
2066 ident.span.with_ctxt(SyntaxContext::empty())
2067 } else if ns == TypeNS {
2070 ident.span.modern_and_legacy()
2073 // Walk backwards up the ribs in scope.
2074 let record_used = record_used_id.is_some();
2075 let mut module = self.graph_root;
2076 for i in (0 .. self.ribs[ns].len()).rev() {
2077 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2078 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2079 // The ident resolves to a type parameter or local variable.
2080 return Some(LexicalScopeBinding::Def(
2081 self.adjust_local_def(ns, i, def, record_used, path_span)
2085 module = match self.ribs[ns][i].kind {
2086 ModuleRibKind(module) => module,
2087 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2088 // If an invocation of this macro created `ident`, give up on `ident`
2089 // and switch to `ident`'s source from the macro definition.
2090 ident.span.remove_mark();
2096 let item = self.resolve_ident_in_module_unadjusted(
2097 ModuleOrUniformRoot::Module(module),
2103 if let Ok(binding) = item {
2104 // The ident resolves to an item.
2105 return Some(LexicalScopeBinding::Item(binding));
2109 ModuleKind::Block(..) => {}, // We can see through blocks
2114 ident.span = ident.span.modern();
2115 let mut poisoned = None;
2117 let opt_module = if let Some(node_id) = record_used_id {
2118 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2119 node_id, &mut poisoned)
2121 self.hygienic_lexical_parent(module, &mut ident.span)
2123 module = unwrap_or!(opt_module, break);
2124 let orig_current_module = self.current_module;
2125 self.current_module = module; // Lexical resolutions can never be a privacy error.
2126 let result = self.resolve_ident_in_module_unadjusted(
2127 ModuleOrUniformRoot::Module(module),
2133 self.current_module = orig_current_module;
2137 if let Some(node_id) = poisoned {
2138 self.session.buffer_lint_with_diagnostic(
2139 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2140 node_id, ident.span,
2141 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2142 lint::builtin::BuiltinLintDiagnostics::
2143 ProcMacroDeriveResolutionFallback(ident.span),
2146 return Some(LexicalScopeBinding::Item(binding))
2148 Err(Determined) => continue,
2149 Err(Undetermined) =>
2150 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2154 if !module.no_implicit_prelude {
2156 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2157 return Some(LexicalScopeBinding::Item(binding));
2160 if ns == TypeNS && is_known_tool(ident.name) {
2161 let binding = (Def::ToolMod, ty::Visibility::Public,
2162 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2163 return Some(LexicalScopeBinding::Item(binding));
2165 if let Some(prelude) = self.prelude {
2166 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2167 ModuleOrUniformRoot::Module(prelude),
2173 return Some(LexicalScopeBinding::Item(binding));
2181 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2182 -> Option<Module<'a>> {
2183 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2184 return Some(self.macro_def_scope(span.remove_mark()));
2187 if let ModuleKind::Block(..) = module.kind {
2188 return Some(module.parent.unwrap());
2194 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2195 span: &mut Span, node_id: NodeId,
2196 poisoned: &mut Option<NodeId>)
2197 -> Option<Module<'a>> {
2198 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2202 // We need to support the next case under a deprecation warning
2205 // ---- begin: this comes from a proc macro derive
2206 // mod implementation_details {
2207 // // Note that `MyStruct` is not in scope here.
2208 // impl SomeTrait for MyStruct { ... }
2212 // So we have to fall back to the module's parent during lexical resolution in this case.
2213 if let Some(parent) = module.parent {
2214 // Inner module is inside the macro, parent module is outside of the macro.
2215 if module.expansion != parent.expansion &&
2216 module.expansion.is_descendant_of(parent.expansion) {
2217 // The macro is a proc macro derive
2218 if module.expansion.looks_like_proc_macro_derive() {
2219 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2220 *poisoned = Some(node_id);
2221 return module.parent;
2230 fn resolve_ident_in_module(
2232 module: ModuleOrUniformRoot<'a>,
2235 parent_scope: Option<&ParentScope<'a>>,
2238 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2239 self.resolve_ident_in_module_ext(
2240 module, ident, ns, parent_scope, record_used, path_span
2241 ).map_err(|(determinacy, _)| determinacy)
2244 fn resolve_ident_in_module_ext(
2246 module: ModuleOrUniformRoot<'a>,
2249 parent_scope: Option<&ParentScope<'a>>,
2252 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2253 let orig_current_module = self.current_module;
2255 ModuleOrUniformRoot::Module(module) => {
2256 ident.span = ident.span.modern();
2257 if let Some(def) = ident.span.adjust(module.expansion) {
2258 self.current_module = self.macro_def_scope(def);
2261 ModuleOrUniformRoot::ExternPrelude => {
2262 ident.span = ident.span.modern();
2263 ident.span.adjust(Mark::root());
2265 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2266 ModuleOrUniformRoot::CurrentScope => {
2270 let result = self.resolve_ident_in_module_unadjusted_ext(
2271 module, ident, ns, parent_scope, false, record_used, path_span,
2273 self.current_module = orig_current_module;
2277 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2278 let mut ctxt = ident.span.ctxt();
2279 let mark = if ident.name == keywords::DollarCrate.name() {
2280 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2281 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2282 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2283 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2284 // definitions actually produced by `macro` and `macro` definitions produced by
2285 // `macro_rules!`, but at least such configurations are not stable yet.
2286 ctxt = ctxt.modern_and_legacy();
2287 let mut iter = ctxt.marks().into_iter().rev().peekable();
2288 let mut result = None;
2289 // Find the last modern mark from the end if it exists.
2290 while let Some(&(mark, transparency)) = iter.peek() {
2291 if transparency == Transparency::Opaque {
2292 result = Some(mark);
2298 // Then find the last legacy mark from the end if it exists.
2299 for (mark, transparency) in iter {
2300 if transparency == Transparency::SemiTransparent {
2301 result = Some(mark);
2308 ctxt = ctxt.modern();
2309 ctxt.adjust(Mark::root())
2311 let module = match mark {
2312 Some(def) => self.macro_def_scope(def),
2313 None => return self.graph_root,
2315 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2318 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2319 let mut module = self.get_module(module.normal_ancestor_id);
2320 while module.span.ctxt().modern() != *ctxt {
2321 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2322 module = self.get_module(parent.normal_ancestor_id);
2329 // We maintain a list of value ribs and type ribs.
2331 // Simultaneously, we keep track of the current position in the module
2332 // graph in the `current_module` pointer. When we go to resolve a name in
2333 // the value or type namespaces, we first look through all the ribs and
2334 // then query the module graph. When we resolve a name in the module
2335 // namespace, we can skip all the ribs (since nested modules are not
2336 // allowed within blocks in Rust) and jump straight to the current module
2339 // Named implementations are handled separately. When we find a method
2340 // call, we consult the module node to find all of the implementations in
2341 // scope. This information is lazily cached in the module node. We then
2342 // generate a fake "implementation scope" containing all the
2343 // implementations thus found, for compatibility with old resolve pass.
2345 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2346 where F: FnOnce(&mut Resolver<'_>) -> T
2348 let id = self.definitions.local_def_id(id);
2349 let module = self.module_map.get(&id).cloned(); // clones a reference
2350 if let Some(module) = module {
2351 // Move down in the graph.
2352 let orig_module = replace(&mut self.current_module, module);
2353 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2354 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2356 self.finalize_current_module_macro_resolutions();
2359 self.current_module = orig_module;
2360 self.ribs[ValueNS].pop();
2361 self.ribs[TypeNS].pop();
2368 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2369 /// is returned by the given predicate function
2371 /// Stops after meeting a closure.
2372 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2373 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2375 for rib in self.label_ribs.iter().rev() {
2378 // If an invocation of this macro created `ident`, give up on `ident`
2379 // and switch to `ident`'s source from the macro definition.
2380 MacroDefinition(def) => {
2381 if def == self.macro_def(ident.span.ctxt()) {
2382 ident.span.remove_mark();
2386 // Do not resolve labels across function boundary
2390 let r = pred(rib, ident);
2398 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2399 debug!("resolve_adt");
2400 self.with_current_self_item(item, |this| {
2401 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2402 let item_def_id = this.definitions.local_def_id(item.id);
2403 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2404 visit::walk_item(this, item);
2410 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2411 let segments = &use_tree.prefix.segments;
2412 if !segments.is_empty() {
2413 let ident = segments[0].ident;
2414 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2418 let nss = match use_tree.kind {
2419 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2422 let report_error = |this: &Self, ns| {
2423 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2424 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2428 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2429 Some(LexicalScopeBinding::Def(..)) => {
2430 report_error(self, ns);
2432 Some(LexicalScopeBinding::Item(binding)) => {
2433 let orig_blacklisted_binding =
2434 mem::replace(&mut self.blacklisted_binding, Some(binding));
2435 if let Some(LexicalScopeBinding::Def(..)) =
2436 self.resolve_ident_in_lexical_scope(ident, ns, None,
2437 use_tree.prefix.span) {
2438 report_error(self, ns);
2440 self.blacklisted_binding = orig_blacklisted_binding;
2445 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2446 for (use_tree, _) in use_trees {
2447 self.future_proof_import(use_tree);
2452 fn resolve_item(&mut self, item: &Item) {
2453 let name = item.ident.name;
2454 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2457 ItemKind::Ty(_, ref generics) |
2458 ItemKind::Fn(_, _, ref generics, _) |
2459 ItemKind::Existential(_, ref generics) => {
2460 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2461 |this| visit::walk_item(this, item));
2464 ItemKind::Enum(_, ref generics) |
2465 ItemKind::Struct(_, ref generics) |
2466 ItemKind::Union(_, ref generics) => {
2467 self.resolve_adt(item, generics);
2470 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2471 self.resolve_implementation(generics,
2477 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2478 // Create a new rib for the trait-wide type parameters.
2479 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2480 let local_def_id = this.definitions.local_def_id(item.id);
2481 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2482 this.visit_generics(generics);
2483 walk_list!(this, visit_param_bound, bounds);
2485 for trait_item in trait_items {
2486 let generic_params = HasGenericParams(&trait_item.generics,
2487 TraitOrImplItemRibKind);
2488 this.with_generic_param_rib(generic_params, |this| {
2489 match trait_item.node {
2490 TraitItemKind::Const(ref ty, ref default) => {
2493 // Only impose the restrictions of
2494 // ConstRibKind for an actual constant
2495 // expression in a provided default.
2496 if let Some(ref expr) = *default{
2497 this.with_constant_rib(|this| {
2498 this.visit_expr(expr);
2502 TraitItemKind::Method(_, _) => {
2503 visit::walk_trait_item(this, trait_item)
2505 TraitItemKind::Type(..) => {
2506 visit::walk_trait_item(this, trait_item)
2508 TraitItemKind::Macro(_) => {
2509 panic!("unexpanded macro in resolve!")
2518 ItemKind::TraitAlias(ref generics, ref bounds) => {
2519 // Create a new rib for the trait-wide type parameters.
2520 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2521 let local_def_id = this.definitions.local_def_id(item.id);
2522 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2523 this.visit_generics(generics);
2524 walk_list!(this, visit_param_bound, bounds);
2529 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2530 self.with_scope(item.id, |this| {
2531 visit::walk_item(this, item);
2535 ItemKind::Static(ref ty, _, ref expr) |
2536 ItemKind::Const(ref ty, ref expr) => {
2537 debug!("resolve_item ItemKind::Const");
2538 self.with_item_rib(|this| {
2540 this.with_constant_rib(|this| {
2541 this.visit_expr(expr);
2546 ItemKind::Use(ref use_tree) => {
2547 self.future_proof_import(use_tree);
2550 ItemKind::ExternCrate(..) |
2551 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2552 // do nothing, these are just around to be encoded
2555 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2559 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2560 where F: FnOnce(&mut Resolver<'_>)
2562 debug!("with_generic_param_rib");
2563 match generic_params {
2564 HasGenericParams(generics, rib_kind) => {
2565 let mut function_type_rib = Rib::new(rib_kind);
2566 let mut function_value_rib = Rib::new(rib_kind);
2567 let mut seen_bindings = FxHashMap::default();
2568 for param in &generics.params {
2570 GenericParamKind::Lifetime { .. } => {}
2571 GenericParamKind::Type { .. } => {
2572 let ident = param.ident.modern();
2573 debug!("with_generic_param_rib: {}", param.id);
2575 if seen_bindings.contains_key(&ident) {
2576 let span = seen_bindings.get(&ident).unwrap();
2577 let err = ResolutionError::NameAlreadyUsedInParameterList(
2581 resolve_error(self, param.ident.span, err);
2583 seen_bindings.entry(ident).or_insert(param.ident.span);
2585 // Plain insert (no renaming).
2586 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2587 function_type_rib.bindings.insert(ident, def);
2588 self.record_def(param.id, PathResolution::new(def));
2590 GenericParamKind::Const { .. } => {
2591 let ident = param.ident.modern();
2592 debug!("with_generic_param_rib: {}", param.id);
2594 if seen_bindings.contains_key(&ident) {
2595 let span = seen_bindings.get(&ident).unwrap();
2596 let err = ResolutionError::NameAlreadyUsedInParameterList(
2600 resolve_error(self, param.ident.span, err);
2602 seen_bindings.entry(ident).or_insert(param.ident.span);
2604 let def = Def::ConstParam(self.definitions.local_def_id(param.id));
2605 function_value_rib.bindings.insert(ident, def);
2606 self.record_def(param.id, PathResolution::new(def));
2610 self.ribs[ValueNS].push(function_value_rib);
2611 self.ribs[TypeNS].push(function_type_rib);
2614 NoGenericParams => {
2621 if let HasGenericParams(..) = generic_params {
2622 self.ribs[TypeNS].pop();
2623 self.ribs[ValueNS].pop();
2627 fn with_label_rib<F>(&mut self, f: F)
2628 where F: FnOnce(&mut Resolver<'_>)
2630 self.label_ribs.push(Rib::new(NormalRibKind));
2632 self.label_ribs.pop();
2635 fn with_item_rib<F>(&mut self, f: F)
2636 where F: FnOnce(&mut Resolver<'_>)
2638 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2639 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2641 self.ribs[TypeNS].pop();
2642 self.ribs[ValueNS].pop();
2645 fn with_constant_rib<F>(&mut self, f: F)
2646 where F: FnOnce(&mut Resolver<'_>)
2648 debug!("with_constant_rib");
2649 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2650 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2652 self.label_ribs.pop();
2653 self.ribs[ValueNS].pop();
2656 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2657 where F: FnOnce(&mut Resolver<'_>) -> T
2659 // Handle nested impls (inside fn bodies)
2660 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2661 let result = f(self);
2662 self.current_self_type = previous_value;
2666 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2667 where F: FnOnce(&mut Resolver<'_>) -> T
2669 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2670 let result = f(self);
2671 self.current_self_item = previous_value;
2675 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2676 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2677 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2679 let mut new_val = None;
2680 let mut new_id = None;
2681 if let Some(trait_ref) = opt_trait_ref {
2682 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2683 let def = self.smart_resolve_path_fragment(
2687 trait_ref.path.span,
2688 PathSource::Trait(AliasPossibility::No),
2689 CrateLint::SimplePath(trait_ref.ref_id),
2691 if def != Def::Err {
2692 new_id = Some(def.def_id());
2693 let span = trait_ref.path.span;
2694 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2695 self.resolve_path_without_parent_scope(
2700 CrateLint::SimplePath(trait_ref.ref_id),
2703 new_val = Some((module, trait_ref.clone()));
2707 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2708 let result = f(self, new_id);
2709 self.current_trait_ref = original_trait_ref;
2713 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2714 where F: FnOnce(&mut Resolver<'_>)
2716 let mut self_type_rib = Rib::new(NormalRibKind);
2718 // Plain insert (no renaming, since types are not currently hygienic)
2719 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2720 self.ribs[TypeNS].push(self_type_rib);
2722 self.ribs[TypeNS].pop();
2725 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2726 where F: FnOnce(&mut Resolver<'_>)
2728 let self_def = Def::SelfCtor(impl_id);
2729 let mut self_type_rib = Rib::new(NormalRibKind);
2730 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2731 self.ribs[ValueNS].push(self_type_rib);
2733 self.ribs[ValueNS].pop();
2736 fn resolve_implementation(&mut self,
2737 generics: &Generics,
2738 opt_trait_reference: &Option<TraitRef>,
2741 impl_items: &[ImplItem]) {
2742 debug!("resolve_implementation");
2743 // If applicable, create a rib for the type parameters.
2744 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2745 // Dummy self type for better errors if `Self` is used in the trait path.
2746 this.with_self_rib(Def::SelfTy(None, None), |this| {
2747 // Resolve the trait reference, if necessary.
2748 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2749 let item_def_id = this.definitions.local_def_id(item_id);
2750 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2751 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2752 // Resolve type arguments in the trait path.
2753 visit::walk_trait_ref(this, trait_ref);
2755 // Resolve the self type.
2756 this.visit_ty(self_type);
2757 // Resolve the generic parameters.
2758 this.visit_generics(generics);
2759 // Resolve the items within the impl.
2760 this.with_current_self_type(self_type, |this| {
2761 this.with_self_struct_ctor_rib(item_def_id, |this| {
2762 debug!("resolve_implementation with_self_struct_ctor_rib");
2763 for impl_item in impl_items {
2764 this.resolve_visibility(&impl_item.vis);
2766 // We also need a new scope for the impl item type parameters.
2767 let generic_params = HasGenericParams(&impl_item.generics,
2768 TraitOrImplItemRibKind);
2769 this.with_generic_param_rib(generic_params, |this| {
2770 use self::ResolutionError::*;
2771 match impl_item.node {
2772 ImplItemKind::Const(..) => {
2774 "resolve_implementation ImplItemKind::Const",
2776 // If this is a trait impl, ensure the const
2778 this.check_trait_item(
2782 |n, s| ConstNotMemberOfTrait(n, s),
2785 this.with_constant_rib(|this| {
2786 visit::walk_impl_item(this, impl_item)
2789 ImplItemKind::Method(..) => {
2790 // If this is a trait impl, ensure the method
2792 this.check_trait_item(impl_item.ident,
2795 |n, s| MethodNotMemberOfTrait(n, s));
2797 visit::walk_impl_item(this, impl_item);
2799 ImplItemKind::Type(ref ty) => {
2800 // If this is a trait impl, ensure the type
2802 this.check_trait_item(impl_item.ident,
2805 |n, s| TypeNotMemberOfTrait(n, s));
2809 ImplItemKind::Existential(ref bounds) => {
2810 // If this is a trait impl, ensure the type
2812 this.check_trait_item(impl_item.ident,
2815 |n, s| TypeNotMemberOfTrait(n, s));
2817 for bound in bounds {
2818 this.visit_param_bound(bound);
2821 ImplItemKind::Macro(_) =>
2822 panic!("unexpanded macro in resolve!"),
2834 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2835 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2837 // If there is a TraitRef in scope for an impl, then the method must be in the
2839 if let Some((module, _)) = self.current_trait_ref {
2840 if self.resolve_ident_in_module(
2841 ModuleOrUniformRoot::Module(module),
2848 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2849 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2854 fn resolve_local(&mut self, local: &Local) {
2855 // Resolve the type.
2856 walk_list!(self, visit_ty, &local.ty);
2858 // Resolve the initializer.
2859 walk_list!(self, visit_expr, &local.init);
2861 // Resolve the pattern.
2862 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2865 // build a map from pattern identifiers to binding-info's.
2866 // this is done hygienically. This could arise for a macro
2867 // that expands into an or-pattern where one 'x' was from the
2868 // user and one 'x' came from the macro.
2869 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2870 let mut binding_map = FxHashMap::default();
2872 pat.walk(&mut |pat| {
2873 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2874 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2875 Some(Def::Local(..)) => true,
2878 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2879 binding_map.insert(ident, binding_info);
2888 // check that all of the arms in an or-pattern have exactly the
2889 // same set of bindings, with the same binding modes for each.
2890 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2891 if pats.is_empty() {
2895 let mut missing_vars = FxHashMap::default();
2896 let mut inconsistent_vars = FxHashMap::default();
2897 for (i, p) in pats.iter().enumerate() {
2898 let map_i = self.binding_mode_map(&p);
2900 for (j, q) in pats.iter().enumerate() {
2905 let map_j = self.binding_mode_map(&q);
2906 for (&key, &binding_i) in &map_i {
2907 if map_j.is_empty() { // Account for missing bindings when
2908 let binding_error = missing_vars // map_j has none.
2910 .or_insert(BindingError {
2912 origin: BTreeSet::new(),
2913 target: BTreeSet::new(),
2915 binding_error.origin.insert(binding_i.span);
2916 binding_error.target.insert(q.span);
2918 for (&key_j, &binding_j) in &map_j {
2919 match map_i.get(&key_j) {
2920 None => { // missing binding
2921 let binding_error = missing_vars
2923 .or_insert(BindingError {
2925 origin: BTreeSet::new(),
2926 target: BTreeSet::new(),
2928 binding_error.origin.insert(binding_j.span);
2929 binding_error.target.insert(p.span);
2931 Some(binding_i) => { // check consistent binding
2932 if binding_i.binding_mode != binding_j.binding_mode {
2935 .or_insert((binding_j.span, binding_i.span));
2943 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2944 missing_vars.sort();
2945 for (_, v) in missing_vars {
2947 *v.origin.iter().next().unwrap(),
2948 ResolutionError::VariableNotBoundInPattern(v));
2950 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2951 inconsistent_vars.sort();
2952 for (name, v) in inconsistent_vars {
2953 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2957 fn resolve_arm(&mut self, arm: &Arm) {
2958 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2960 let mut bindings_list = FxHashMap::default();
2961 for pattern in &arm.pats {
2962 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2965 // This has to happen *after* we determine which pat_idents are variants.
2966 self.check_consistent_bindings(&arm.pats);
2968 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2969 self.visit_expr(expr)
2971 self.visit_expr(&arm.body);
2973 self.ribs[ValueNS].pop();
2976 fn resolve_block(&mut self, block: &Block) {
2977 debug!("(resolving block) entering block");
2978 // Move down in the graph, if there's an anonymous module rooted here.
2979 let orig_module = self.current_module;
2980 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2982 let mut num_macro_definition_ribs = 0;
2983 if let Some(anonymous_module) = anonymous_module {
2984 debug!("(resolving block) found anonymous module, moving down");
2985 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2986 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2987 self.current_module = anonymous_module;
2988 self.finalize_current_module_macro_resolutions();
2990 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2993 // Descend into the block.
2994 for stmt in &block.stmts {
2995 if let ast::StmtKind::Item(ref item) = stmt.node {
2996 if let ast::ItemKind::MacroDef(..) = item.node {
2997 num_macro_definition_ribs += 1;
2998 let def = self.definitions.local_def_id(item.id);
2999 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
3000 self.label_ribs.push(Rib::new(MacroDefinition(def)));
3004 self.visit_stmt(stmt);
3008 self.current_module = orig_module;
3009 for _ in 0 .. num_macro_definition_ribs {
3010 self.ribs[ValueNS].pop();
3011 self.label_ribs.pop();
3013 self.ribs[ValueNS].pop();
3014 if anonymous_module.is_some() {
3015 self.ribs[TypeNS].pop();
3017 debug!("(resolving block) leaving block");
3020 fn fresh_binding(&mut self,
3023 outer_pat_id: NodeId,
3024 pat_src: PatternSource,
3025 bindings: &mut FxHashMap<Ident, NodeId>)
3027 // Add the binding to the local ribs, if it
3028 // doesn't already exist in the bindings map. (We
3029 // must not add it if it's in the bindings map
3030 // because that breaks the assumptions later
3031 // passes make about or-patterns.)
3032 let ident = ident.modern_and_legacy();
3033 let mut def = Def::Local(pat_id);
3034 match bindings.get(&ident).cloned() {
3035 Some(id) if id == outer_pat_id => {
3036 // `Variant(a, a)`, error
3040 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3044 Some(..) if pat_src == PatternSource::FnParam => {
3045 // `fn f(a: u8, a: u8)`, error
3049 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3053 Some(..) if pat_src == PatternSource::Match ||
3054 pat_src == PatternSource::IfLet ||
3055 pat_src == PatternSource::WhileLet => {
3056 // `Variant1(a) | Variant2(a)`, ok
3057 // Reuse definition from the first `a`.
3058 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3061 span_bug!(ident.span, "two bindings with the same name from \
3062 unexpected pattern source {:?}", pat_src);
3065 // A completely fresh binding, add to the lists if it's valid.
3066 if ident.name != keywords::Invalid.name() {
3067 bindings.insert(ident, outer_pat_id);
3068 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3073 PathResolution::new(def)
3076 fn resolve_pattern(&mut self,
3078 pat_src: PatternSource,
3079 // Maps idents to the node ID for the
3080 // outermost pattern that binds them.
3081 bindings: &mut FxHashMap<Ident, NodeId>) {
3082 // Visit all direct subpatterns of this pattern.
3083 let outer_pat_id = pat.id;
3084 pat.walk(&mut |pat| {
3085 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3087 PatKind::Ident(bmode, ident, ref opt_pat) => {
3088 // First try to resolve the identifier as some existing
3089 // entity, then fall back to a fresh binding.
3090 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3092 .and_then(LexicalScopeBinding::item);
3093 let resolution = binding.map(NameBinding::def).and_then(|def| {
3094 let is_syntactic_ambiguity = opt_pat.is_none() &&
3095 bmode == BindingMode::ByValue(Mutability::Immutable);
3097 Def::Ctor(_, _, CtorKind::Const) |
3098 Def::Const(..) if is_syntactic_ambiguity => {
3099 // Disambiguate in favor of a unit struct/variant
3100 // or constant pattern.
3101 self.record_use(ident, ValueNS, binding.unwrap(), false);
3102 Some(PathResolution::new(def))
3104 Def::Ctor(..) | Def::Const(..) | Def::Static(..) => {
3105 // This is unambiguously a fresh binding, either syntactically
3106 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3107 // to something unusable as a pattern (e.g., constructor function),
3108 // but we still conservatively report an error, see
3109 // issues/33118#issuecomment-233962221 for one reason why.
3113 ResolutionError::BindingShadowsSomethingUnacceptable(
3114 pat_src.descr(), ident.name, binding.unwrap())
3118 Def::Fn(..) | Def::Err => {
3119 // These entities are explicitly allowed
3120 // to be shadowed by fresh bindings.
3124 span_bug!(ident.span, "unexpected definition for an \
3125 identifier in pattern: {:?}", def);
3128 }).unwrap_or_else(|| {
3129 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3132 self.record_def(pat.id, resolution);
3135 PatKind::TupleStruct(ref path, ..) => {
3136 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3139 PatKind::Path(ref qself, ref path) => {
3140 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3143 PatKind::Struct(ref path, ..) => {
3144 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3152 visit::walk_pat(self, pat);
3155 // High-level and context dependent path resolution routine.
3156 // Resolves the path and records the resolution into definition map.
3157 // If resolution fails tries several techniques to find likely
3158 // resolution candidates, suggest imports or other help, and report
3159 // errors in user friendly way.
3160 fn smart_resolve_path(&mut self,
3162 qself: Option<&QSelf>,
3164 source: PathSource<'_>)
3166 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3169 /// A variant of `smart_resolve_path` where you also specify extra
3170 /// information about where the path came from; this extra info is
3171 /// sometimes needed for the lint that recommends rewriting
3172 /// absolute paths to `crate`, so that it knows how to frame the
3173 /// suggestion. If you are just resolving a path like `foo::bar`
3174 /// that appears in an arbitrary location, then you just want
3175 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3176 /// already provides.
3177 fn smart_resolve_path_with_crate_lint(
3180 qself: Option<&QSelf>,
3182 source: PathSource<'_>,
3183 crate_lint: CrateLint
3184 ) -> PathResolution {
3185 self.smart_resolve_path_fragment(
3188 &Segment::from_path(path),
3195 fn smart_resolve_path_fragment(&mut self,
3197 qself: Option<&QSelf>,
3200 source: PathSource<'_>,
3201 crate_lint: CrateLint)
3203 let ns = source.namespace();
3204 let is_expected = &|def| source.is_expected(def);
3206 let report_errors = |this: &mut Self, def: Option<Def>| {
3207 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, def);
3208 let def_id = this.current_module.normal_ancestor_id;
3209 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3210 let better = def.is_some();
3211 this.use_injections.push(UseError { err, candidates, node_id, better });
3212 err_path_resolution()
3215 let resolution = match self.resolve_qpath_anywhere(
3221 source.defer_to_typeck(),
3222 source.global_by_default(),
3225 Some(resolution) if resolution.unresolved_segments() == 0 => {
3226 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3229 // Add a temporary hack to smooth the transition to new struct ctor
3230 // visibility rules. See #38932 for more details.
3232 if let Def::Struct(def_id) = resolution.base_def() {
3233 if let Some((ctor_def, ctor_vis))
3234 = self.struct_constructors.get(&def_id).cloned() {
3235 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3236 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3237 self.session.buffer_lint(lint, id, span,
3238 "private struct constructors are not usable through \
3239 re-exports in outer modules",
3241 res = Some(PathResolution::new(ctor_def));
3246 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3249 Some(resolution) if source.defer_to_typeck() => {
3250 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3251 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3252 // it needs to be added to the trait map.
3254 let item_name = path.last().unwrap().ident;
3255 let traits = self.get_traits_containing_item(item_name, ns);
3256 self.trait_map.insert(id, traits);
3260 _ => report_errors(self, None)
3263 if let PathSource::TraitItem(..) = source {} else {
3264 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3265 self.record_def(id, resolution);
3270 /// Only used in a specific case of type ascription suggestions
3272 fn get_colon_suggestion_span(&self, start: Span) -> Span {
3273 let cm = self.session.source_map();
3274 start.to(cm.next_point(start))
3277 fn type_ascription_suggestion(
3279 err: &mut DiagnosticBuilder<'_>,
3282 debug!("type_ascription_suggetion {:?}", base_span);
3283 let cm = self.session.source_map();
3284 let base_snippet = cm.span_to_snippet(base_span);
3285 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3286 if let Some(sp) = self.current_type_ascription.last() {
3289 // Try to find the `:`; bail on first non-':' / non-whitespace.
3290 sp = cm.next_point(sp);
3291 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3292 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3293 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3295 let mut show_label = true;
3296 if line_sp != line_base_sp {
3297 err.span_suggestion_short(
3299 "did you mean to use `;` here instead?",
3301 Applicability::MaybeIncorrect,
3304 let colon_sp = self.get_colon_suggestion_span(sp);
3305 let after_colon_sp = self.get_colon_suggestion_span(
3306 colon_sp.shrink_to_hi(),
3308 if !cm.span_to_snippet(after_colon_sp).map(|s| s == " ")
3311 err.span_suggestion(
3313 "maybe you meant to write a path separator here",
3315 Applicability::MaybeIncorrect,
3319 if let Ok(base_snippet) = base_snippet {
3320 let mut sp = after_colon_sp;
3322 // Try to find an assignment
3323 sp = cm.next_point(sp);
3324 let snippet = cm.span_to_snippet(sp.to(cm.next_point(sp)));
3326 Ok(ref x) if x.as_str() == "=" => {
3327 err.span_suggestion(
3329 "maybe you meant to write an assignment here",
3330 format!("let {}", base_snippet),
3331 Applicability::MaybeIncorrect,
3336 Ok(ref x) if x.as_str() == "\n" => break,
3344 err.span_label(base_span,
3345 "expecting a type here because of type ascription");
3348 } else if !snippet.trim().is_empty() {
3349 debug!("tried to find type ascription `:` token, couldn't find it");
3359 fn self_type_is_available(&mut self, span: Span) -> bool {
3360 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3361 TypeNS, None, span);
3362 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3365 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3366 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3367 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3368 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3371 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3372 fn resolve_qpath_anywhere(&mut self,
3374 qself: Option<&QSelf>,
3376 primary_ns: Namespace,
3378 defer_to_typeck: bool,
3379 global_by_default: bool,
3380 crate_lint: CrateLint)
3381 -> Option<PathResolution> {
3382 let mut fin_res = None;
3383 // FIXME: can't resolve paths in macro namespace yet, macros are
3384 // processed by the little special hack below.
3385 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3386 if i == 0 || ns != primary_ns {
3387 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3388 // If defer_to_typeck, then resolution > no resolution,
3389 // otherwise full resolution > partial resolution > no resolution.
3390 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3392 res => if fin_res.is_none() { fin_res = res },
3396 if primary_ns != MacroNS &&
3397 (self.macro_names.contains(&path[0].ident.modern()) ||
3398 self.builtin_macros.get(&path[0].ident.name).cloned()
3399 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3400 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3401 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3402 // Return some dummy definition, it's enough for error reporting.
3404 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3410 /// Handles paths that may refer to associated items.
3411 fn resolve_qpath(&mut self,
3413 qself: Option<&QSelf>,
3417 global_by_default: bool,
3418 crate_lint: CrateLint)
3419 -> Option<PathResolution> {
3421 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3422 ns={:?}, span={:?}, global_by_default={:?})",
3431 if let Some(qself) = qself {
3432 if qself.position == 0 {
3433 // This is a case like `<T>::B`, where there is no
3434 // trait to resolve. In that case, we leave the `B`
3435 // segment to be resolved by type-check.
3436 return Some(PathResolution::with_unresolved_segments(
3437 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3441 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3443 // Currently, `path` names the full item (`A::B::C`, in
3444 // our example). so we extract the prefix of that that is
3445 // the trait (the slice upto and including
3446 // `qself.position`). And then we recursively resolve that,
3447 // but with `qself` set to `None`.
3449 // However, setting `qself` to none (but not changing the
3450 // span) loses the information about where this path
3451 // *actually* appears, so for the purposes of the crate
3452 // lint we pass along information that this is the trait
3453 // name from a fully qualified path, and this also
3454 // contains the full span (the `CrateLint::QPathTrait`).
3455 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3456 let res = self.smart_resolve_path_fragment(
3459 &path[..=qself.position],
3461 PathSource::TraitItem(ns),
3462 CrateLint::QPathTrait {
3464 qpath_span: qself.path_span,
3468 // The remaining segments (the `C` in our example) will
3469 // have to be resolved by type-check, since that requires doing
3470 // trait resolution.
3471 return Some(PathResolution::with_unresolved_segments(
3472 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3476 let result = match self.resolve_path_without_parent_scope(
3483 PathResult::NonModule(path_res) => path_res,
3484 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3485 PathResolution::new(module.def().unwrap())
3487 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3488 // don't report an error right away, but try to fallback to a primitive type.
3489 // So, we are still able to successfully resolve something like
3491 // use std::u8; // bring module u8 in scope
3492 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3493 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3494 // // not to non-existent std::u8::max_value
3497 // Such behavior is required for backward compatibility.
3498 // The same fallback is used when `a` resolves to nothing.
3499 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3500 PathResult::Failed { .. }
3501 if (ns == TypeNS || path.len() > 1) &&
3502 self.primitive_type_table.primitive_types
3503 .contains_key(&path[0].ident.name) => {
3504 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3505 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3507 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3508 PathResolution::new(module.def().unwrap()),
3509 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
3510 resolve_error(self, span, ResolutionError::FailedToResolve { label, suggestion });
3511 err_path_resolution()
3513 PathResult::Module(..) | PathResult::Failed { .. } => return None,
3514 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3517 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3518 path[0].ident.name != keywords::PathRoot.name() &&
3519 path[0].ident.name != keywords::DollarCrate.name() {
3520 let unqualified_result = {
3521 match self.resolve_path_without_parent_scope(
3522 &[*path.last().unwrap()],
3528 PathResult::NonModule(path_res) => path_res.base_def(),
3529 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3530 module.def().unwrap(),
3531 _ => return Some(result),
3534 if result.base_def() == unqualified_result {
3535 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3536 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3543 fn resolve_path_without_parent_scope(
3546 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3549 crate_lint: CrateLint,
3550 ) -> PathResult<'a> {
3551 // Macro and import paths must have full parent scope available during resolution,
3552 // other paths will do okay with parent module alone.
3553 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3554 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3555 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3561 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3562 parent_scope: &ParentScope<'a>,
3565 crate_lint: CrateLint,
3566 ) -> PathResult<'a> {
3567 let mut module = None;
3568 let mut allow_super = true;
3569 let mut second_binding = None;
3570 self.current_module = parent_scope.module;
3573 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3574 path_span={:?}, crate_lint={:?})",
3582 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3583 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3584 let record_segment_def = |this: &mut Self, def| {
3586 if let Some(id) = id {
3587 if !this.def_map.contains_key(&id) {
3588 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3589 this.record_def(id, PathResolution::new(def));
3595 let is_last = i == path.len() - 1;
3596 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3597 let name = ident.name;
3599 allow_super &= ns == TypeNS &&
3600 (name == keywords::SelfLower.name() ||
3601 name == keywords::Super.name());
3604 if allow_super && name == keywords::Super.name() {
3605 let mut ctxt = ident.span.ctxt().modern();
3606 let self_module = match i {
3607 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3609 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3613 if let Some(self_module) = self_module {
3614 if let Some(parent) = self_module.parent {
3615 module = Some(ModuleOrUniformRoot::Module(
3616 self.resolve_self(&mut ctxt, parent)));
3620 let msg = "there are too many initial `super`s.".to_string();
3621 return PathResult::Failed {
3625 is_error_from_last_segment: false,
3629 if name == keywords::SelfLower.name() {
3630 let mut ctxt = ident.span.ctxt().modern();
3631 module = Some(ModuleOrUniformRoot::Module(
3632 self.resolve_self(&mut ctxt, self.current_module)));
3635 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3636 module = Some(ModuleOrUniformRoot::ExternPrelude);
3639 if name == keywords::PathRoot.name() &&
3640 ident.span.rust_2015() && self.session.rust_2018() {
3641 // `::a::b` from 2015 macro on 2018 global edition
3642 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3645 if name == keywords::PathRoot.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::PathRoot.name() {
3659 "crate root".to_string()
3661 format!("`{}`", name)
3663 let label = if i == 1 && path[0].ident.name == keywords::PathRoot.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 {
3672 is_error_from_last_segment: false,
3676 let binding = if let Some(module) = module {
3677 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3678 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3679 assert!(ns == TypeNS);
3680 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3681 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3682 record_used, path_span)
3684 let record_used_id =
3685 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3686 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3687 // we found a locally-imported or available item/module
3688 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3689 // we found a local variable or type param
3690 Some(LexicalScopeBinding::Def(def))
3691 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3692 record_segment_def(self, def);
3693 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3697 _ => Err(Determinacy::determined(record_used)),
3704 second_binding = Some(binding);
3706 let def = binding.def();
3707 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3708 if let Some(next_module) = binding.module() {
3709 module = Some(ModuleOrUniformRoot::Module(next_module));
3710 record_segment_def(self, def);
3711 } else if def == Def::ToolMod && i + 1 != path.len() {
3712 if binding.is_import() {
3713 self.session.struct_span_err(
3714 ident.span, "cannot use a tool module through an import"
3716 binding.span, "the tool module imported here"
3719 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3720 return PathResult::NonModule(PathResolution::new(def));
3721 } else if def == Def::Err {
3722 return PathResult::NonModule(err_path_resolution());
3723 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3724 self.lint_if_path_starts_with_module(
3730 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3731 def, path.len() - i - 1
3734 return PathResult::Failed {
3736 label: format!("not a module `{}`", ident),
3738 is_error_from_last_segment: is_last,
3742 Err(Undetermined) => return PathResult::Indeterminate,
3743 Err(Determined) => {
3744 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3745 if opt_ns.is_some() && !module.is_normal() {
3746 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3747 module.def().unwrap(), path.len() - i
3751 let module_def = match module {
3752 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3755 let (label, suggestion) = if module_def == self.graph_root.def() {
3756 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3757 let mut candidates =
3758 self.lookup_import_candidates(ident, TypeNS, is_mod);
3759 candidates.sort_by_cached_key(|c| {
3760 (c.path.segments.len(), c.path.to_string())
3762 if let Some(candidate) = candidates.get(0) {
3764 String::from("unresolved import"),
3767 String::from("a similar path exists"),
3768 candidate.path.to_string(),
3769 Applicability::MaybeIncorrect,
3772 } else if !ident.is_reserved() {
3773 (format!("maybe a missing `extern crate {};`?", ident), None)
3775 // the parser will already have complained about the keyword being used
3776 return PathResult::NonModule(err_path_resolution());
3779 (format!("use of undeclared type or module `{}`", ident), None)
3781 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
3783 return PathResult::Failed {
3787 is_error_from_last_segment: is_last,
3793 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3795 PathResult::Module(match module {
3796 Some(module) => module,
3797 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3798 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3802 fn lint_if_path_starts_with_module(
3804 crate_lint: CrateLint,
3807 second_binding: Option<&NameBinding<'_>>,
3809 let (diag_id, diag_span) = match crate_lint {
3810 CrateLint::No => return,
3811 CrateLint::SimplePath(id) => (id, path_span),
3812 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3813 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3816 let first_name = match path.get(0) {
3817 // In the 2018 edition this lint is a hard error, so nothing to do
3818 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3822 // We're only interested in `use` paths which should start with
3823 // `{{root}}` currently.
3824 if first_name != keywords::PathRoot.name() {
3829 // If this import looks like `crate::...` it's already good
3830 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3831 // Otherwise go below to see if it's an extern crate
3833 // If the path has length one (and it's `PathRoot` most likely)
3834 // then we don't know whether we're gonna be importing a crate or an
3835 // item in our crate. Defer this lint to elsewhere
3839 // If the first element of our path was actually resolved to an
3840 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3841 // warning, this looks all good!
3842 if let Some(binding) = second_binding {
3843 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3844 // Careful: we still want to rewrite paths from
3845 // renamed extern crates.
3846 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3852 let diag = lint::builtin::BuiltinLintDiagnostics
3853 ::AbsPathWithModule(diag_span);
3854 self.session.buffer_lint_with_diagnostic(
3855 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3857 "absolute paths must start with `self`, `super`, \
3858 `crate`, or an external crate name in the 2018 edition",
3862 // Resolve a local definition, potentially adjusting for closures.
3863 fn adjust_local_def(&mut self,
3868 span: Span) -> Def {
3869 debug!("adjust_local_def");
3870 let ribs = &self.ribs[ns][rib_index + 1..];
3872 // An invalid forward use of a type parameter from a previous default.
3873 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3875 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3877 assert_eq!(def, Def::Err);
3883 span_bug!(span, "unexpected {:?} in bindings", def)
3885 Def::Local(node_id) => {
3886 use ResolutionError::*;
3887 let mut res_err = None;
3891 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3892 ForwardTyParamBanRibKind => {
3893 // Nothing to do. Continue.
3895 ClosureRibKind(function_id) => {
3898 let seen = self.freevars_seen
3901 if let Some(&index) = seen.get(&node_id) {
3902 def = Def::Upvar(node_id, index, function_id);
3905 let vec = self.freevars
3908 let depth = vec.len();
3909 def = Def::Upvar(node_id, depth, function_id);
3916 seen.insert(node_id, depth);
3919 ItemRibKind | FnItemRibKind | TraitOrImplItemRibKind => {
3920 // This was an attempt to access an upvar inside a
3921 // named function item. This is not allowed, so we
3924 // We don't immediately trigger a resolve error, because
3925 // we want certain other resolution errors (namely those
3926 // emitted for `ConstantItemRibKind` below) to take
3928 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
3931 ConstantItemRibKind => {
3932 // Still doesn't deal with upvars
3934 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
3940 if let Some(res_err) = res_err {
3941 resolve_error(self, span, res_err);
3945 Def::TyParam(..) | Def::SelfTy(..) => {
3948 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3949 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3950 ConstantItemRibKind => {
3951 // Nothing to do. Continue.
3953 ItemRibKind | FnItemRibKind => {
3954 // This was an attempt to use a type parameter outside its scope.
3959 ResolutionError::GenericParamsFromOuterFunction(def),
3967 Def::ConstParam(..) => {
3968 let mut ribs = ribs.iter().peekable();
3969 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
3970 // When declaring const parameters inside function signatures, the first rib
3971 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
3972 // (spuriously) conflicting with the const param.
3976 if let ItemRibKind | FnItemRibKind = rib.kind {
3977 // This was an attempt to use a const parameter outside its scope.
3982 ResolutionError::GenericParamsFromOuterFunction(def),
3994 fn lookup_assoc_candidate<FilterFn>(&mut self,
3997 filter_fn: FilterFn)
3998 -> Option<AssocSuggestion>
3999 where FilterFn: Fn(Def) -> bool
4001 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4003 TyKind::Path(None, _) => Some(t.id),
4004 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4005 // This doesn't handle the remaining `Ty` variants as they are not
4006 // that commonly the self_type, it might be interesting to provide
4007 // support for those in future.
4012 // Fields are generally expected in the same contexts as locals.
4013 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4014 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4015 // Look for a field with the same name in the current self_type.
4016 if let Some(resolution) = self.def_map.get(&node_id) {
4017 match resolution.base_def() {
4018 Def::Struct(did) | Def::Union(did)
4019 if resolution.unresolved_segments() == 0 => {
4020 if let Some(field_names) = self.field_names.get(&did) {
4021 if field_names.iter().any(|&field_name| ident.name == field_name) {
4022 return Some(AssocSuggestion::Field);
4032 // Look for associated items in the current trait.
4033 if let Some((module, _)) = self.current_trait_ref {
4034 if let Ok(binding) = self.resolve_ident_in_module(
4035 ModuleOrUniformRoot::Module(module),
4042 let def = binding.def();
4044 return Some(if self.has_self.contains(&def.def_id()) {
4045 AssocSuggestion::MethodWithSelf
4047 AssocSuggestion::AssocItem
4056 fn lookup_typo_candidate<FilterFn>(
4060 filter_fn: FilterFn,
4062 ) -> Option<TypoSuggestion>
4064 FilterFn: Fn(Def) -> bool,
4066 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4067 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4068 if let Some(binding) = resolution.borrow().binding {
4069 if filter_fn(binding.def()) {
4070 names.push(TypoSuggestion {
4071 candidate: ident.name,
4072 article: binding.def().article(),
4073 kind: binding.def().kind_name(),
4080 let mut names = Vec::new();
4081 if path.len() == 1 {
4082 // Search in lexical scope.
4083 // Walk backwards up the ribs in scope and collect candidates.
4084 for rib in self.ribs[ns].iter().rev() {
4085 // Locals and type parameters
4086 for (ident, def) in &rib.bindings {
4087 if filter_fn(*def) {
4088 names.push(TypoSuggestion {
4089 candidate: ident.name,
4090 article: def.article(),
4091 kind: def.kind_name(),
4096 if let ModuleRibKind(module) = rib.kind {
4097 // Items from this module
4098 add_module_candidates(module, &mut names);
4100 if let ModuleKind::Block(..) = module.kind {
4101 // We can see through blocks
4103 // Items from the prelude
4104 if !module.no_implicit_prelude {
4105 names.extend(self.extern_prelude.clone().iter().flat_map(|(ident, _)| {
4107 .maybe_process_path_extern(ident.name, ident.span)
4108 .and_then(|crate_id| {
4109 let crate_mod = Def::Mod(DefId {
4111 index: CRATE_DEF_INDEX,
4114 if filter_fn(crate_mod) {
4115 Some(TypoSuggestion {
4116 candidate: ident.name,
4126 if let Some(prelude) = self.prelude {
4127 add_module_candidates(prelude, &mut names);
4134 // Add primitive types to the mix
4135 if filter_fn(Def::PrimTy(Bool)) {
4137 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4141 kind: "primitive type",
4147 // Search in module.
4148 let mod_path = &path[..path.len() - 1];
4149 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4150 mod_path, Some(TypeNS), false, span, CrateLint::No
4152 if let ModuleOrUniformRoot::Module(module) = module {
4153 add_module_candidates(module, &mut names);
4158 let name = path[path.len() - 1].ident.name;
4159 // Make sure error reporting is deterministic.
4160 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4162 match find_best_match_for_name(
4163 names.iter().map(|suggestion| &suggestion.candidate),
4167 Some(found) if found != name => names
4169 .find(|suggestion| suggestion.candidate == found),
4174 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4175 where F: FnOnce(&mut Resolver<'_>)
4177 if let Some(label) = label {
4178 self.unused_labels.insert(id, label.ident.span);
4179 let def = Def::Label(id);
4180 self.with_label_rib(|this| {
4181 let ident = label.ident.modern_and_legacy();
4182 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4190 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4191 self.with_resolved_label(label, id, |this| this.visit_block(block));
4194 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4195 // First, record candidate traits for this expression if it could
4196 // result in the invocation of a method call.
4198 self.record_candidate_traits_for_expr_if_necessary(expr);
4200 // Next, resolve the node.
4202 ExprKind::Path(ref qself, ref path) => {
4203 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4204 visit::walk_expr(self, expr);
4207 ExprKind::Struct(ref path, ..) => {
4208 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4209 visit::walk_expr(self, expr);
4212 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4213 let def = self.search_label(label.ident, |rib, ident| {
4214 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4218 // Search again for close matches...
4219 // Picks the first label that is "close enough", which is not necessarily
4220 // the closest match
4221 let close_match = self.search_label(label.ident, |rib, ident| {
4222 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4223 find_best_match_for_name(names, &*ident.as_str(), None)
4225 self.record_def(expr.id, err_path_resolution());
4228 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4231 Some(Def::Label(id)) => {
4232 // Since this def is a label, it is never read.
4233 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4234 self.unused_labels.remove(&id);
4237 span_bug!(expr.span, "label wasn't mapped to a label def!");
4241 // visit `break` argument if any
4242 visit::walk_expr(self, expr);
4245 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4246 self.visit_expr(subexpression);
4248 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4249 let mut bindings_list = FxHashMap::default();
4251 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4253 // This has to happen *after* we determine which pat_idents are variants
4254 self.check_consistent_bindings(pats);
4255 self.visit_block(if_block);
4256 self.ribs[ValueNS].pop();
4258 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4261 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4263 ExprKind::While(ref subexpression, ref block, label) => {
4264 self.with_resolved_label(label, expr.id, |this| {
4265 this.visit_expr(subexpression);
4266 this.visit_block(block);
4270 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4271 self.with_resolved_label(label, expr.id, |this| {
4272 this.visit_expr(subexpression);
4273 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4274 let mut bindings_list = FxHashMap::default();
4276 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4278 // This has to happen *after* we determine which pat_idents are variants.
4279 this.check_consistent_bindings(pats);
4280 this.visit_block(block);
4281 this.ribs[ValueNS].pop();
4285 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4286 self.visit_expr(subexpression);
4287 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4288 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4290 self.resolve_labeled_block(label, expr.id, block);
4292 self.ribs[ValueNS].pop();
4295 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4297 // Equivalent to `visit::walk_expr` + passing some context to children.
4298 ExprKind::Field(ref subexpression, _) => {
4299 self.resolve_expr(subexpression, Some(expr));
4301 ExprKind::MethodCall(ref segment, ref arguments) => {
4302 let mut arguments = arguments.iter();
4303 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4304 for argument in arguments {
4305 self.resolve_expr(argument, None);
4307 self.visit_path_segment(expr.span, segment);
4310 ExprKind::Call(ref callee, ref arguments) => {
4311 self.resolve_expr(callee, Some(expr));
4312 for argument in arguments {
4313 self.resolve_expr(argument, None);
4316 ExprKind::Type(ref type_expr, _) => {
4317 self.current_type_ascription.push(type_expr.span);
4318 visit::walk_expr(self, expr);
4319 self.current_type_ascription.pop();
4321 // Resolve the body of async exprs inside the async closure to which they desugar
4322 ExprKind::Async(_, async_closure_id, ref block) => {
4323 let rib_kind = ClosureRibKind(async_closure_id);
4324 self.ribs[ValueNS].push(Rib::new(rib_kind));
4325 self.label_ribs.push(Rib::new(rib_kind));
4326 self.visit_block(&block);
4327 self.label_ribs.pop();
4328 self.ribs[ValueNS].pop();
4330 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4331 // resolve the arguments within the proper scopes so that usages of them inside the
4332 // closure are detected as upvars rather than normal closure arg usages.
4334 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4335 ref fn_decl, ref body, _span,
4337 let rib_kind = ClosureRibKind(expr.id);
4338 self.ribs[ValueNS].push(Rib::new(rib_kind));
4339 self.label_ribs.push(Rib::new(rib_kind));
4340 // Resolve arguments:
4341 let mut bindings_list = FxHashMap::default();
4342 for argument in &fn_decl.inputs {
4343 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4344 self.visit_ty(&argument.ty);
4346 // No need to resolve return type-- the outer closure return type is
4347 // FunctionRetTy::Default
4349 // Now resolve the inner closure
4351 let rib_kind = ClosureRibKind(inner_closure_id);
4352 self.ribs[ValueNS].push(Rib::new(rib_kind));
4353 self.label_ribs.push(Rib::new(rib_kind));
4354 // No need to resolve arguments: the inner closure has none.
4355 // Resolve the return type:
4356 visit::walk_fn_ret_ty(self, &fn_decl.output);
4358 self.visit_expr(body);
4359 self.label_ribs.pop();
4360 self.ribs[ValueNS].pop();
4362 self.label_ribs.pop();
4363 self.ribs[ValueNS].pop();
4366 visit::walk_expr(self, expr);
4371 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4373 ExprKind::Field(_, ident) => {
4374 // FIXME(#6890): Even though you can't treat a method like a
4375 // field, we need to add any trait methods we find that match
4376 // the field name so that we can do some nice error reporting
4377 // later on in typeck.
4378 let traits = self.get_traits_containing_item(ident, ValueNS);
4379 self.trait_map.insert(expr.id, traits);
4381 ExprKind::MethodCall(ref segment, ..) => {
4382 debug!("(recording candidate traits for expr) recording traits for {}",
4384 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4385 self.trait_map.insert(expr.id, traits);
4393 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4394 -> Vec<TraitCandidate> {
4395 debug!("(getting traits containing item) looking for '{}'", ident.name);
4397 let mut found_traits = Vec::new();
4398 // Look for the current trait.
4399 if let Some((module, _)) = self.current_trait_ref {
4400 if self.resolve_ident_in_module(
4401 ModuleOrUniformRoot::Module(module),
4408 let def_id = module.def_id().unwrap();
4409 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4413 ident.span = ident.span.modern();
4414 let mut search_module = self.current_module;
4416 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4417 search_module = unwrap_or!(
4418 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4422 if let Some(prelude) = self.prelude {
4423 if !search_module.no_implicit_prelude {
4424 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4431 fn get_traits_in_module_containing_item(&mut self,
4435 found_traits: &mut Vec<TraitCandidate>) {
4436 assert!(ns == TypeNS || ns == ValueNS);
4437 let mut traits = module.traits.borrow_mut();
4438 if traits.is_none() {
4439 let mut collected_traits = Vec::new();
4440 module.for_each_child(|name, ns, binding| {
4441 if ns != TypeNS { return }
4442 match binding.def() {
4444 Def::TraitAlias(_) => collected_traits.push((name, binding)),
4448 *traits = Some(collected_traits.into_boxed_slice());
4451 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4452 // Traits have pseudo-modules that can be used to search for the given ident.
4453 if let Some(module) = binding.module() {
4454 let mut ident = ident;
4455 if ident.span.glob_adjust(
4457 binding.span.ctxt().modern(),
4461 if self.resolve_ident_in_module_unadjusted(
4462 ModuleOrUniformRoot::Module(module),
4468 let import_id = match binding.kind {
4469 NameBindingKind::Import { directive, .. } => {
4470 self.maybe_unused_trait_imports.insert(directive.id);
4471 self.add_to_glob_map(&directive, trait_name);
4476 let trait_def_id = module.def_id().unwrap();
4477 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id });
4479 } else if let Def::TraitAlias(_) = binding.def() {
4480 // For now, just treat all trait aliases as possible candidates, since we don't
4481 // know if the ident is somewhere in the transitive bounds.
4483 let import_id = match binding.kind {
4484 NameBindingKind::Import { directive, .. } => {
4485 self.maybe_unused_trait_imports.insert(directive.id);
4486 self.add_to_glob_map(&directive, trait_name);
4491 let trait_def_id = binding.def().def_id();
4492 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id });
4494 bug!("candidate is not trait or trait alias?")
4499 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4500 lookup_ident: Ident,
4501 namespace: Namespace,
4502 start_module: &'a ModuleData<'a>,
4504 filter_fn: FilterFn)
4505 -> Vec<ImportSuggestion>
4506 where FilterFn: Fn(Def) -> bool
4508 let mut candidates = Vec::new();
4509 let mut seen_modules = FxHashSet::default();
4510 let not_local_module = crate_name != keywords::Crate.ident();
4511 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4513 while let Some((in_module,
4515 in_module_is_extern)) = worklist.pop() {
4516 self.populate_module_if_necessary(in_module);
4518 // We have to visit module children in deterministic order to avoid
4519 // instabilities in reported imports (#43552).
4520 in_module.for_each_child_stable(|ident, ns, name_binding| {
4521 // avoid imports entirely
4522 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4523 // avoid non-importable candidates as well
4524 if !name_binding.is_importable() { return; }
4526 // collect results based on the filter function
4527 if ident.name == lookup_ident.name && ns == namespace {
4528 let def = name_binding.def();
4531 let mut segms = path_segments.clone();
4532 if lookup_ident.span.rust_2018() {
4533 // crate-local absolute paths start with `crate::` in edition 2018
4534 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4536 0, ast::PathSegment::from_ident(crate_name)
4540 segms.push(ast::PathSegment::from_ident(ident));
4542 span: name_binding.span,
4545 // the entity is accessible in the following cases:
4546 // 1. if it's defined in the same crate, it's always
4547 // accessible (since private entities can be made public)
4548 // 2. if it's defined in another crate, it's accessible
4549 // only if both the module is public and the entity is
4550 // declared as public (due to pruning, we don't explore
4551 // outside crate private modules => no need to check this)
4552 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4553 let did = match def {
4554 Def::Ctor(did, ..) => self.parent(did),
4555 _ => def.opt_def_id(),
4557 candidates.push(ImportSuggestion { did, path });
4562 // collect submodules to explore
4563 if let Some(module) = name_binding.module() {
4565 let mut path_segments = path_segments.clone();
4566 path_segments.push(ast::PathSegment::from_ident(ident));
4568 let is_extern_crate_that_also_appears_in_prelude =
4569 name_binding.is_extern_crate() &&
4570 lookup_ident.span.rust_2018();
4572 let is_visible_to_user =
4573 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4575 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4576 // add the module to the lookup
4577 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4578 if seen_modules.insert(module.def_id().unwrap()) {
4579 worklist.push((module, path_segments, is_extern));
4589 /// When name resolution fails, this method can be used to look up candidate
4590 /// entities with the expected name. It allows filtering them using the
4591 /// supplied predicate (which should be used to only accept the types of
4592 /// definitions expected, e.g., traits). The lookup spans across all crates.
4594 /// N.B., the method does not look into imports, but this is not a problem,
4595 /// since we report the definitions (thus, the de-aliased imports).
4596 fn lookup_import_candidates<FilterFn>(&mut self,
4597 lookup_ident: Ident,
4598 namespace: Namespace,
4599 filter_fn: FilterFn)
4600 -> Vec<ImportSuggestion>
4601 where FilterFn: Fn(Def) -> bool
4603 let mut suggestions = self.lookup_import_candidates_from_module(
4604 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4606 if lookup_ident.span.rust_2018() {
4607 let extern_prelude_names = self.extern_prelude.clone();
4608 for (ident, _) in extern_prelude_names.into_iter() {
4609 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4611 let crate_root = self.get_module(DefId {
4613 index: CRATE_DEF_INDEX,
4615 self.populate_module_if_necessary(&crate_root);
4617 suggestions.extend(self.lookup_import_candidates_from_module(
4618 lookup_ident, namespace, crate_root, ident, &filter_fn));
4626 fn find_module(&mut self,
4628 -> Option<(Module<'a>, ImportSuggestion)>
4630 let mut result = None;
4631 let mut seen_modules = FxHashSet::default();
4632 let mut worklist = vec![(self.graph_root, Vec::new())];
4634 while let Some((in_module, path_segments)) = worklist.pop() {
4635 // abort if the module is already found
4636 if result.is_some() { break; }
4638 self.populate_module_if_necessary(in_module);
4640 in_module.for_each_child_stable(|ident, _, name_binding| {
4641 // abort if the module is already found or if name_binding is private external
4642 if result.is_some() || !name_binding.vis.is_visible_locally() {
4645 if let Some(module) = name_binding.module() {
4647 let mut path_segments = path_segments.clone();
4648 path_segments.push(ast::PathSegment::from_ident(ident));
4649 if module.def() == Some(module_def) {
4651 span: name_binding.span,
4652 segments: path_segments,
4654 let did = module.def().and_then(|def| def.opt_def_id());
4655 result = Some((module, ImportSuggestion { did, path }));
4657 // add the module to the lookup
4658 if seen_modules.insert(module.def_id().unwrap()) {
4659 worklist.push((module, path_segments));
4669 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4670 if let Def::Enum(..) = enum_def {} else {
4671 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4674 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4675 self.populate_module_if_necessary(enum_module);
4677 let mut variants = Vec::new();
4678 enum_module.for_each_child_stable(|ident, _, name_binding| {
4679 if let Def::Variant(..) = name_binding.def() {
4680 let mut segms = enum_import_suggestion.path.segments.clone();
4681 segms.push(ast::PathSegment::from_ident(ident));
4682 variants.push(Path {
4683 span: name_binding.span,
4692 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4693 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4694 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4695 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4699 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4701 ast::VisibilityKind::Public => ty::Visibility::Public,
4702 ast::VisibilityKind::Crate(..) => {
4703 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4705 ast::VisibilityKind::Inherited => {
4706 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4708 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4709 // For visibilities we are not ready to provide correct implementation of "uniform
4710 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4711 // On 2015 edition visibilities are resolved as crate-relative by default,
4712 // so we are prepending a root segment if necessary.
4713 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4714 let crate_root = if ident.is_path_segment_keyword() {
4716 } else if ident.span.rust_2018() {
4717 let msg = "relative paths are not supported in visibilities on 2018 edition";
4718 self.session.struct_span_err(ident.span, msg)
4722 format!("crate::{}", path),
4723 Applicability::MaybeIncorrect,
4726 return ty::Visibility::Public;
4728 let ctxt = ident.span.ctxt();
4729 Some(Segment::from_ident(Ident::new(
4730 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4734 let segments = crate_root.into_iter()
4735 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4736 let def = self.smart_resolve_path_fragment(
4741 PathSource::Visibility,
4742 CrateLint::SimplePath(id),
4744 if def == Def::Err {
4745 ty::Visibility::Public
4747 let vis = ty::Visibility::Restricted(def.def_id());
4748 if self.is_accessible(vis) {
4751 self.session.span_err(path.span, "visibilities can only be restricted \
4752 to ancestor modules");
4753 ty::Visibility::Public
4760 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4761 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4764 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4765 vis.is_accessible_from(module.normal_ancestor_id, self)
4768 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4769 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4770 if !ptr::eq(module, old_module) {
4771 span_bug!(binding.span, "parent module is reset for binding");
4776 fn disambiguate_legacy_vs_modern(
4778 legacy: &'a NameBinding<'a>,
4779 modern: &'a NameBinding<'a>,
4781 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4782 // is disambiguated to mitigate regressions from macro modularization.
4783 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4784 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4785 self.binding_parent_modules.get(&PtrKey(modern))) {
4786 (Some(legacy), Some(modern)) =>
4787 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4788 modern.is_ancestor_of(legacy),
4793 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4794 if b.span.is_dummy() {
4795 let add_built_in = match b.def() {
4796 // These already contain the "built-in" prefix or look bad with it.
4797 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4800 let (built_in, from) = if from_prelude {
4801 ("", " from prelude")
4802 } else if b.is_extern_crate() && !b.is_import() &&
4803 self.session.opts.externs.get(&ident.as_str()).is_some() {
4804 ("", " passed with `--extern`")
4805 } else if add_built_in {
4811 let article = if built_in.is_empty() { b.article() } else { "a" };
4812 format!("{a}{built_in} {thing}{from}",
4813 a = article, thing = b.descr(), built_in = built_in, from = from)
4815 let introduced = if b.is_import() { "imported" } else { "defined" };
4816 format!("the {thing} {introduced} here",
4817 thing = b.descr(), introduced = introduced)
4821 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4822 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4823 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4824 // We have to print the span-less alternative first, otherwise formatting looks bad.
4825 (b2, b1, misc2, misc1, true)
4827 (b1, b2, misc1, misc2, false)
4830 let mut err = struct_span_err!(self.session, ident.span, E0659,
4831 "`{ident}` is ambiguous ({why})",
4832 ident = ident, why = kind.descr());
4833 err.span_label(ident.span, "ambiguous name");
4835 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4836 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4837 let note_msg = format!("`{ident}` could{also} refer to {what}",
4838 ident = ident, also = also, what = what);
4840 let mut help_msgs = Vec::new();
4841 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4842 kind == AmbiguityKind::GlobVsExpanded ||
4843 kind == AmbiguityKind::GlobVsOuter &&
4844 swapped != also.is_empty()) {
4845 help_msgs.push(format!("consider adding an explicit import of \
4846 `{ident}` to disambiguate", ident = ident))
4848 if b.is_extern_crate() && ident.span.rust_2018() {
4849 help_msgs.push(format!(
4850 "use `::{ident}` to refer to this {thing} unambiguously",
4851 ident = ident, thing = b.descr(),
4854 if misc == AmbiguityErrorMisc::SuggestCrate {
4855 help_msgs.push(format!(
4856 "use `crate::{ident}` to refer to this {thing} unambiguously",
4857 ident = ident, thing = b.descr(),
4859 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4860 help_msgs.push(format!(
4861 "use `self::{ident}` to refer to this {thing} unambiguously",
4862 ident = ident, thing = b.descr(),
4866 err.span_note(b.span, ¬e_msg);
4867 for (i, help_msg) in help_msgs.iter().enumerate() {
4868 let or = if i == 0 { "" } else { "or " };
4869 err.help(&format!("{}{}", or, help_msg));
4873 could_refer_to(b1, misc1, "");
4874 could_refer_to(b2, misc2, " also");
4878 fn report_errors(&mut self, krate: &Crate) {
4879 self.report_with_use_injections(krate);
4881 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4882 let msg = "macro-expanded `macro_export` macros from the current crate \
4883 cannot be referred to by absolute paths";
4884 self.session.buffer_lint_with_diagnostic(
4885 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4886 CRATE_NODE_ID, span_use, msg,
4887 lint::builtin::BuiltinLintDiagnostics::
4888 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4892 for ambiguity_error in &self.ambiguity_errors {
4893 self.report_ambiguity_error(ambiguity_error);
4896 let mut reported_spans = FxHashSet::default();
4897 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4898 if reported_spans.insert(dedup_span) {
4899 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4900 binding.descr(), ident.name);
4905 fn report_with_use_injections(&mut self, krate: &Crate) {
4906 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4907 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4908 if !candidates.is_empty() {
4909 show_candidates(&mut err, span, &candidates, better, found_use);
4915 fn report_conflict<'b>(&mut self,
4919 new_binding: &NameBinding<'b>,
4920 old_binding: &NameBinding<'b>) {
4921 // Error on the second of two conflicting names
4922 if old_binding.span.lo() > new_binding.span.lo() {
4923 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4926 let container = match parent.kind {
4927 ModuleKind::Def(Def::Mod(_), _) => "module",
4928 ModuleKind::Def(Def::Trait(_), _) => "trait",
4929 ModuleKind::Block(..) => "block",
4933 let old_noun = match old_binding.is_import() {
4935 false => "definition",
4938 let new_participle = match new_binding.is_import() {
4943 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4945 if let Some(s) = self.name_already_seen.get(&name) {
4951 let old_kind = match (ns, old_binding.module()) {
4952 (ValueNS, _) => "value",
4953 (MacroNS, _) => "macro",
4954 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4955 (TypeNS, Some(module)) if module.is_normal() => "module",
4956 (TypeNS, Some(module)) if module.is_trait() => "trait",
4957 (TypeNS, _) => "type",
4960 let msg = format!("the name `{}` is defined multiple times", name);
4962 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4963 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4964 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4965 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4966 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4968 _ => match (old_binding.is_import(), new_binding.is_import()) {
4969 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4970 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4971 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4975 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4980 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4982 self.session.source_map().def_span(old_binding.span),
4983 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
4986 // See https://github.com/rust-lang/rust/issues/32354
4987 use NameBindingKind::Import;
4988 let directive = match (&new_binding.kind, &old_binding.kind) {
4989 // If there are two imports where one or both have attributes then prefer removing the
4990 // import without attributes.
4991 (Import { directive: new, .. }, Import { directive: old, .. }) if {
4992 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
4993 (new.has_attributes || old.has_attributes)
4995 if old.has_attributes {
4996 Some((new, new_binding.span, true))
4998 Some((old, old_binding.span, true))
5001 // Otherwise prioritize the new binding.
5002 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5003 Some((directive, new_binding.span, other.is_import())),
5004 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5005 Some((directive, old_binding.span, other.is_import())),
5009 // Check if the target of the use for both bindings is the same.
5010 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5011 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5012 let from_item = self.extern_prelude.get(&ident)
5013 .map(|entry| entry.introduced_by_item)
5015 // Only suggest removing an import if both bindings are to the same def, if both spans
5016 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5017 // been introduced by a item.
5018 let should_remove_import = duplicate && !has_dummy_span &&
5019 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5022 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5023 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5024 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5025 // Simple case - remove the entire import. Due to the above match arm, this can
5026 // only be a single use so just remove it entirely.
5027 err.tool_only_span_suggestion(
5028 directive.use_span_with_attributes,
5029 "remove unnecessary import",
5031 Applicability::MaybeIncorrect,
5034 Some((directive, span, _)) =>
5035 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5040 self.name_already_seen.insert(name, span);
5043 /// This function adds a suggestion to change the binding name of a new import that conflicts
5044 /// with an existing import.
5046 /// ```ignore (diagnostic)
5047 /// help: you can use `as` to change the binding name of the import
5049 /// LL | use foo::bar as other_bar;
5050 /// | ^^^^^^^^^^^^^^^^^^^^^
5052 fn add_suggestion_for_rename_of_use(
5054 err: &mut DiagnosticBuilder<'_>,
5056 directive: &ImportDirective<'_>,
5059 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5060 format!("Other{}", name)
5062 format!("other_{}", name)
5065 let mut suggestion = None;
5066 match directive.subclass {
5067 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5068 suggestion = Some(format!("self as {}", suggested_name)),
5069 ImportDirectiveSubclass::SingleImport { source, .. } => {
5070 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5071 .map(|pos| pos as usize) {
5072 if let Ok(snippet) = self.session.source_map()
5073 .span_to_snippet(binding_span) {
5074 if pos <= snippet.len() {
5075 suggestion = Some(format!(
5079 if snippet.ends_with(";") { ";" } else { "" }
5085 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5086 suggestion = Some(format!(
5087 "extern crate {} as {};",
5088 source.unwrap_or(target.name),
5091 _ => unreachable!(),
5094 let rename_msg = "you can use `as` to change the binding name of the import";
5095 if let Some(suggestion) = suggestion {
5096 err.span_suggestion(
5100 Applicability::MaybeIncorrect,
5103 err.span_label(binding_span, rename_msg);
5107 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5108 /// nested. In the following example, this function will be invoked to remove the `a` binding
5109 /// in the second use statement:
5111 /// ```ignore (diagnostic)
5112 /// use issue_52891::a;
5113 /// use issue_52891::{d, a, e};
5116 /// The following suggestion will be added:
5118 /// ```ignore (diagnostic)
5119 /// use issue_52891::{d, a, e};
5120 /// ^-- help: remove unnecessary import
5123 /// If the nested use contains only one import then the suggestion will remove the entire
5126 /// It is expected that the directive provided is a nested import - this isn't checked by the
5127 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5128 /// as characters expected by span manipulations won't be present.
5129 fn add_suggestion_for_duplicate_nested_use(
5131 err: &mut DiagnosticBuilder<'_>,
5132 directive: &ImportDirective<'_>,
5135 assert!(directive.is_nested());
5136 let message = "remove unnecessary import";
5137 let source_map = self.session.source_map();
5139 // Two examples will be used to illustrate the span manipulations we're doing:
5141 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5142 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5143 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5144 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5146 // Find the span of everything after the binding.
5147 // ie. `a, e};` or `a};`
5148 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5150 // Find everything after the binding but not including the binding.
5151 // ie. `, e};` or `};`
5152 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5154 // Keep characters in the span until we encounter something that isn't a comma or
5158 // Also note whether a closing brace character was encountered. If there
5159 // was, then later go backwards to remove any trailing commas that are left.
5160 let mut found_closing_brace = false;
5161 let after_binding_until_next_binding = source_map.span_take_while(
5162 after_binding_until_end,
5164 if ch == '}' { found_closing_brace = true; }
5165 ch == ' ' || ch == ','
5169 // Combine the two spans.
5170 // ie. `a, ` or `a`.
5172 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5173 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5175 // If there was a closing brace then identify the span to remove any trailing commas from
5176 // previous imports.
5177 if found_closing_brace {
5178 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5179 // `prev_source` will contain all of the source that came before the span.
5180 // Then split based on a command and take the first (ie. closest to our span)
5181 // snippet. In the example, this is a space.
5182 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5183 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5184 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5185 let prev_comma = prev_comma.first().unwrap();
5186 let prev_starting_brace = prev_starting_brace.first().unwrap();
5188 // If the amount of source code before the comma is greater than
5189 // the amount of source code before the starting brace then we've only
5190 // got one item in the nested item (eg. `issue_52891::{self}`).
5191 if prev_comma.len() > prev_starting_brace.len() {
5192 // So just remove the entire line...
5193 err.span_suggestion(
5194 directive.use_span_with_attributes,
5197 Applicability::MaybeIncorrect,
5202 let span = span.with_lo(BytePos(
5203 // Take away the number of bytes for the characters we've found and an
5204 // extra for the comma.
5205 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5207 err.tool_only_span_suggestion(
5208 span, message, String::new(), Applicability::MaybeIncorrect,
5215 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5218 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5219 -> Option<&'a NameBinding<'a>> {
5220 if ident.is_path_segment_keyword() {
5221 // Make sure `self`, `super` etc produce an error when passed to here.
5224 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5225 if let Some(binding) = entry.extern_crate_item {
5226 if !speculative && entry.introduced_by_item {
5227 self.record_use(ident, TypeNS, binding, false);
5231 let crate_id = if !speculative {
5232 self.crate_loader.process_path_extern(ident.name, ident.span)
5233 } else if let Some(crate_id) =
5234 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5239 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5240 self.populate_module_if_necessary(&crate_root);
5241 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5242 .to_name_binding(self.arenas))
5248 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5249 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5252 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5253 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5256 fn names_to_string(idents: &[Ident]) -> String {
5257 let mut result = String::new();
5258 for (i, ident) in idents.iter()
5259 .filter(|ident| ident.name != keywords::PathRoot.name())
5262 result.push_str("::");
5264 result.push_str(&ident.as_str());
5269 fn path_names_to_string(path: &Path) -> String {
5270 names_to_string(&path.segments.iter()
5271 .map(|seg| seg.ident)
5272 .collect::<Vec<_>>())
5275 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5276 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5277 let variant_path = &suggestion.path;
5278 let variant_path_string = path_names_to_string(variant_path);
5280 let path_len = suggestion.path.segments.len();
5281 let enum_path = ast::Path {
5282 span: suggestion.path.span,
5283 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5285 let enum_path_string = path_names_to_string(&enum_path);
5287 (variant_path_string, enum_path_string)
5290 /// When an entity with a given name is not available in scope, we search for
5291 /// entities with that name in all crates. This method allows outputting the
5292 /// results of this search in a programmer-friendly way
5293 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5294 // This is `None` if all placement locations are inside expansions
5296 candidates: &[ImportSuggestion],
5300 // we want consistent results across executions, but candidates are produced
5301 // by iterating through a hash map, so make sure they are ordered:
5302 let mut path_strings: Vec<_> =
5303 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5304 path_strings.sort();
5306 let better = if better { "better " } else { "" };
5307 let msg_diff = match path_strings.len() {
5308 1 => " is found in another module, you can import it",
5309 _ => "s are found in other modules, you can import them",
5311 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5313 if let Some(span) = span {
5314 for candidate in &mut path_strings {
5315 // produce an additional newline to separate the new use statement
5316 // from the directly following item.
5317 let additional_newline = if found_use {
5322 *candidate = format!("use {};\n{}", candidate, additional_newline);
5325 err.span_suggestions(
5328 path_strings.into_iter(),
5329 Applicability::Unspecified,
5334 for candidate in path_strings {
5336 msg.push_str(&candidate);
5341 /// A somewhat inefficient routine to obtain the name of a module.
5342 fn module_to_string(module: Module<'_>) -> Option<String> {
5343 let mut names = Vec::new();
5345 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5346 if let ModuleKind::Def(_, name) = module.kind {
5347 if let Some(parent) = module.parent {
5348 names.push(Ident::with_empty_ctxt(name));
5349 collect_mod(names, parent);
5352 // danger, shouldn't be ident?
5353 names.push(Ident::from_str("<opaque>"));
5354 collect_mod(names, module.parent.unwrap());
5357 collect_mod(&mut names, module);
5359 if names.is_empty() {
5362 Some(names_to_string(&names.into_iter()
5364 .collect::<Vec<_>>()))
5367 fn err_path_resolution() -> PathResolution {
5368 PathResolution::new(Def::Err)
5371 #[derive(Copy, Clone, Debug)]
5373 /// Do not issue the lint.
5376 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5377 /// In this case, we can take the span of that path.
5380 /// This lint comes from a `use` statement. In this case, what we
5381 /// care about really is the *root* `use` statement; e.g., if we
5382 /// have nested things like `use a::{b, c}`, we care about the
5384 UsePath { root_id: NodeId, root_span: Span },
5386 /// This is the "trait item" from a fully qualified path. For example,
5387 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5388 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5389 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5393 fn node_id(&self) -> Option<NodeId> {
5395 CrateLint::No => None,
5396 CrateLint::SimplePath(id) |
5397 CrateLint::UsePath { root_id: id, .. } |
5398 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5403 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }