1 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
3 #![feature(crate_visibility_modifier)]
4 #![feature(label_break_value)]
5 #![feature(rustc_diagnostic_macros)]
6 #![feature(slice_sort_by_cached_key)]
8 #![recursion_limit="256"]
10 #![deny(rust_2018_idioms)]
12 use rustc_errors as errors;
14 pub use rustc::hir::def::{Namespace, PerNS};
16 use GenericParameters::*;
19 use rustc::hir::map::{Definitions, DefCollector};
20 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
21 use rustc::middle::cstore::CrateStore;
22 use rustc::session::Session;
24 use rustc::hir::def::*;
25 use rustc::hir::def::Namespace::*;
26 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
27 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
28 use rustc::session::config::nightly_options;
30 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
31 use rustc::{bug, span_bug};
33 use rustc_metadata::creader::CrateLoader;
34 use rustc_metadata::cstore::CStore;
36 use syntax::source_map::SourceMap;
37 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
38 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
39 use syntax::ext::base::SyntaxExtension;
40 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
41 use syntax::ext::base::MacroKind;
42 use syntax::symbol::{Symbol, keywords};
43 use syntax::util::lev_distance::find_best_match_for_name;
45 use syntax::visit::{self, FnKind, Visitor};
47 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
48 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
49 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
50 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
51 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
53 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
55 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
56 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
60 use std::cell::{Cell, RefCell};
61 use std::{cmp, fmt, iter, mem, ptr};
62 use std::collections::BTreeSet;
63 use std::mem::replace;
64 use rustc_data_structures::ptr_key::PtrKey;
65 use rustc_data_structures::sync::Lrc;
67 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
68 use macros::{InvocationData, LegacyBinding, ParentScope};
70 // N.B., this module needs to be declared first so diagnostics are
71 // registered before they are used.
76 mod build_reduced_graph;
79 fn is_known_tool(name: Name) -> bool {
80 ["clippy", "rustfmt"].contains(&&*name.as_str())
90 AbsolutePath(Namespace),
95 /// A free importable items suggested in case of resolution failure.
96 struct ImportSuggestion {
100 /// A field or associated item from self type suggested in case of resolution failure.
101 enum AssocSuggestion {
108 struct BindingError {
110 origin: BTreeSet<Span>,
111 target: BTreeSet<Span>,
114 struct TypoSuggestion {
117 /// The kind of the binding ("crate", "module", etc.)
120 /// An appropriate article to refer to the binding ("a", "an", etc.)
121 article: &'static str,
124 impl PartialOrd for BindingError {
125 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
126 Some(self.cmp(other))
130 impl PartialEq for BindingError {
131 fn eq(&self, other: &BindingError) -> bool {
132 self.name == other.name
136 impl Ord for BindingError {
137 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
138 self.name.cmp(&other.name)
142 enum ResolutionError<'a> {
143 /// error E0401: can't use type or const parameters from outer function
144 GenericParamsFromOuterFunction(Def),
145 /// error E0403: the name is already used for a type/const parameter in this list of
146 /// generic parameters
147 NameAlreadyUsedInParameterList(Name, &'a Span),
148 /// error E0407: method is not a member of trait
149 MethodNotMemberOfTrait(Name, &'a str),
150 /// error E0437: type is not a member of trait
151 TypeNotMemberOfTrait(Name, &'a str),
152 /// error E0438: const is not a member of trait
153 ConstNotMemberOfTrait(Name, &'a str),
154 /// error E0408: variable `{}` is not bound in all patterns
155 VariableNotBoundInPattern(&'a BindingError),
156 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
157 VariableBoundWithDifferentMode(Name, Span),
158 /// error E0415: identifier is bound more than once in this parameter list
159 IdentifierBoundMoreThanOnceInParameterList(&'a str),
160 /// error E0416: identifier is bound more than once in the same pattern
161 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
162 /// error E0426: use of undeclared label
163 UndeclaredLabel(&'a str, Option<Name>),
164 /// error E0429: `self` imports are only allowed within a { } list
165 SelfImportsOnlyAllowedWithin,
166 /// error E0430: `self` import can only appear once in the list
167 SelfImportCanOnlyAppearOnceInTheList,
168 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
169 SelfImportOnlyInImportListWithNonEmptyPrefix,
170 /// error E0433: failed to resolve
171 FailedToResolve(&'a str),
172 /// error E0434: can't capture dynamic environment in a fn item
173 CannotCaptureDynamicEnvironmentInFnItem,
174 /// error E0435: attempt to use a non-constant value in a constant
175 AttemptToUseNonConstantValueInConstant,
176 /// error E0530: X bindings cannot shadow Ys
177 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
178 /// error E0128: type parameters with a default cannot use forward declared identifiers
179 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
182 /// Combines an error with provided span and emits it
184 /// This takes the error provided, combines it with the span and any additional spans inside the
185 /// error and emits it.
186 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
188 resolution_error: ResolutionError<'a>) {
189 resolve_struct_error(resolver, span, resolution_error).emit();
192 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
194 resolution_error: ResolutionError<'a>)
195 -> DiagnosticBuilder<'sess> {
196 match resolution_error {
197 ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
198 let mut err = struct_span_err!(resolver.session,
201 "can't use generic parameters from outer function",
203 err.span_label(span, format!("use of generic parameter from outer function"));
205 let cm = resolver.session.source_map();
207 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
208 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
209 resolver.definitions.opt_span(def_id)
212 reduce_impl_span_to_impl_keyword(cm, impl_span),
213 "`Self` type implicitly declared here, by this `impl`",
216 match (maybe_trait_defid, maybe_impl_defid) {
218 err.span_label(span, "can't use `Self` here");
221 err.span_label(span, "use a type here instead");
223 (None, None) => bug!("`impl` without trait nor type?"),
227 Def::TyParam(def_id) => {
228 if let Some(span) = resolver.definitions.opt_span(def_id) {
229 err.span_label(span, "type variable from outer function");
232 Def::ConstParam(def_id) => {
233 if let Some(span) = resolver.definitions.opt_span(def_id) {
234 err.span_label(span, "const variable from outer function");
238 bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
243 // Try to retrieve the span of the function signature and generate a new message with
244 // a local type or const parameter.
245 let sugg_msg = &format!("try using a local generic parameter instead");
246 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
247 // Suggest the modification to the user
252 Applicability::MachineApplicable,
254 } else if let Some(sp) = cm.generate_fn_name_span(span) {
256 format!("try adding a local generic parameter in this method instead"));
258 err.help(&format!("try using a local generic parameter instead"));
263 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
264 let mut err = struct_span_err!(resolver.session,
267 "the name `{}` is already used for a generic \
268 parameter in this list of generic parameters",
270 err.span_label(span, "already used");
271 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
274 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
275 let mut err = struct_span_err!(resolver.session,
278 "method `{}` is not a member of trait `{}`",
281 err.span_label(span, format!("not a member of trait `{}`", trait_));
284 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
285 let mut err = struct_span_err!(resolver.session,
288 "type `{}` is not a member of trait `{}`",
291 err.span_label(span, format!("not a member of trait `{}`", trait_));
294 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
295 let mut err = struct_span_err!(resolver.session,
298 "const `{}` is not a member of trait `{}`",
301 err.span_label(span, format!("not a member of trait `{}`", trait_));
304 ResolutionError::VariableNotBoundInPattern(binding_error) => {
305 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
306 let msp = MultiSpan::from_spans(target_sp.clone());
307 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
308 let mut err = resolver.session.struct_span_err_with_code(
311 DiagnosticId::Error("E0408".into()),
313 for sp in target_sp {
314 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
316 let origin_sp = binding_error.origin.iter().cloned();
317 for sp in origin_sp {
318 err.span_label(sp, "variable not in all patterns");
322 ResolutionError::VariableBoundWithDifferentMode(variable_name,
323 first_binding_span) => {
324 let mut err = struct_span_err!(resolver.session,
327 "variable `{}` is bound in inconsistent \
328 ways within the same match arm",
330 err.span_label(span, "bound in different ways");
331 err.span_label(first_binding_span, "first binding");
334 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
335 let mut err = struct_span_err!(resolver.session,
338 "identifier `{}` is bound more than once in this parameter list",
340 err.span_label(span, "used as parameter more than once");
343 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
344 let mut err = struct_span_err!(resolver.session,
347 "identifier `{}` is bound more than once in the same pattern",
349 err.span_label(span, "used in a pattern more than once");
352 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
353 let mut err = struct_span_err!(resolver.session,
356 "use of undeclared label `{}`",
358 if let Some(lev_candidate) = lev_candidate {
359 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
361 err.span_label(span, format!("undeclared label `{}`", name));
365 ResolutionError::SelfImportsOnlyAllowedWithin => {
366 struct_span_err!(resolver.session,
370 "`self` imports are only allowed within a { } list")
372 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
373 let mut err = struct_span_err!(resolver.session, span, E0430,
374 "`self` import can only appear once in an import list");
375 err.span_label(span, "can only appear once in an import list");
378 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
379 let mut err = struct_span_err!(resolver.session, span, E0431,
380 "`self` import can only appear in an import list with \
381 a non-empty prefix");
382 err.span_label(span, "can only appear in an import list with a non-empty prefix");
385 ResolutionError::FailedToResolve(msg) => {
386 let mut err = struct_span_err!(resolver.session, span, E0433,
387 "failed to resolve: {}", msg);
388 err.span_label(span, msg);
391 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
392 let mut err = struct_span_err!(resolver.session,
396 "can't capture dynamic environment in a fn item");
397 err.help("use the `|| { ... }` closure form instead");
400 ResolutionError::AttemptToUseNonConstantValueInConstant => {
401 let mut err = struct_span_err!(resolver.session, span, E0435,
402 "attempt to use a non-constant value in a constant");
403 err.span_label(span, "non-constant value");
406 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
407 let shadows_what = binding.descr();
408 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
409 what_binding, shadows_what);
410 err.span_label(span, format!("cannot be named the same as {} {}",
411 binding.article(), shadows_what));
412 let participle = if binding.is_import() { "imported" } else { "defined" };
413 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
414 err.span_label(binding.span, msg);
417 ResolutionError::ForwardDeclaredTyParam => {
418 let mut err = struct_span_err!(resolver.session, span, E0128,
419 "type parameters with a default cannot use \
420 forward declared identifiers");
422 span, "defaulted type parameters cannot be forward declared".to_string());
428 /// Adjust the impl span so that just the `impl` keyword is taken by removing
429 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
430 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
432 /// Attention: The method used is very fragile since it essentially duplicates the work of the
433 /// parser. If you need to use this function or something similar, please consider updating the
434 /// source_map functions and this function to something more robust.
435 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
436 let impl_span = cm.span_until_char(impl_span, '<');
437 let impl_span = cm.span_until_whitespace(impl_span);
441 #[derive(Copy, Clone, Debug)]
444 binding_mode: BindingMode,
447 /// Map from the name in a pattern to its binding mode.
448 type BindingMap = FxHashMap<Ident, BindingInfo>;
450 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
461 fn descr(self) -> &'static str {
463 PatternSource::Match => "match binding",
464 PatternSource::IfLet => "if let binding",
465 PatternSource::WhileLet => "while let binding",
466 PatternSource::Let => "let binding",
467 PatternSource::For => "for binding",
468 PatternSource::FnParam => "function parameter",
473 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
474 enum AliasPossibility {
479 #[derive(Copy, Clone, Debug)]
480 enum PathSource<'a> {
481 // Type paths `Path`.
483 // Trait paths in bounds or impls.
484 Trait(AliasPossibility),
485 // Expression paths `path`, with optional parent context.
486 Expr(Option<&'a Expr>),
487 // Paths in path patterns `Path`.
489 // Paths in struct expressions and patterns `Path { .. }`.
491 // Paths in tuple struct patterns `Path(..)`.
493 // `m::A::B` in `<T as m::A>::B::C`.
494 TraitItem(Namespace),
495 // Path in `pub(path)`
499 impl<'a> PathSource<'a> {
500 fn namespace(self) -> Namespace {
502 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
503 PathSource::Visibility => TypeNS,
504 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
505 PathSource::TraitItem(ns) => ns,
509 fn global_by_default(self) -> bool {
511 PathSource::Visibility => true,
512 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
513 PathSource::Struct | PathSource::TupleStruct |
514 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
518 fn defer_to_typeck(self) -> bool {
520 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
521 PathSource::Struct | PathSource::TupleStruct => true,
522 PathSource::Trait(_) | PathSource::TraitItem(..) |
523 PathSource::Visibility => false,
527 fn descr_expected(self) -> &'static str {
529 PathSource::Type => "type",
530 PathSource::Trait(_) => "trait",
531 PathSource::Pat => "unit struct/variant or constant",
532 PathSource::Struct => "struct, variant or union type",
533 PathSource::TupleStruct => "tuple struct/variant",
534 PathSource::Visibility => "module",
535 PathSource::TraitItem(ns) => match ns {
536 TypeNS => "associated type",
537 ValueNS => "method or associated constant",
538 MacroNS => bug!("associated macro"),
540 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
541 // "function" here means "anything callable" rather than `Def::Fn`,
542 // this is not precise but usually more helpful than just "value".
543 Some(&ExprKind::Call(..)) => "function",
549 fn is_expected(self, def: Def) -> bool {
551 PathSource::Type => match def {
552 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
553 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
554 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
555 Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
558 PathSource::Trait(AliasPossibility::No) => match def {
559 Def::Trait(..) => true,
562 PathSource::Trait(AliasPossibility::Maybe) => match def {
563 Def::Trait(..) => true,
564 Def::TraitAlias(..) => true,
567 PathSource::Expr(..) => match def {
568 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
569 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
570 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
571 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
572 Def::SelfCtor(..) | Def::ConstParam(..) => true,
575 PathSource::Pat => match def {
576 Def::StructCtor(_, CtorKind::Const) |
577 Def::VariantCtor(_, CtorKind::Const) |
578 Def::Const(..) | Def::AssociatedConst(..) |
579 Def::SelfCtor(..) => true,
582 PathSource::TupleStruct => match def {
583 Def::StructCtor(_, CtorKind::Fn) |
584 Def::VariantCtor(_, CtorKind::Fn) |
585 Def::SelfCtor(..) => true,
588 PathSource::Struct => match def {
589 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
590 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
593 PathSource::TraitItem(ns) => match def {
594 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
595 Def::AssociatedTy(..) if ns == TypeNS => true,
598 PathSource::Visibility => match def {
599 Def::Mod(..) => true,
605 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
606 __diagnostic_used!(E0404);
607 __diagnostic_used!(E0405);
608 __diagnostic_used!(E0412);
609 __diagnostic_used!(E0422);
610 __diagnostic_used!(E0423);
611 __diagnostic_used!(E0425);
612 __diagnostic_used!(E0531);
613 __diagnostic_used!(E0532);
614 __diagnostic_used!(E0573);
615 __diagnostic_used!(E0574);
616 __diagnostic_used!(E0575);
617 __diagnostic_used!(E0576);
618 __diagnostic_used!(E0577);
619 __diagnostic_used!(E0578);
620 match (self, has_unexpected_resolution) {
621 (PathSource::Trait(_), true) => "E0404",
622 (PathSource::Trait(_), false) => "E0405",
623 (PathSource::Type, true) => "E0573",
624 (PathSource::Type, false) => "E0412",
625 (PathSource::Struct, true) => "E0574",
626 (PathSource::Struct, false) => "E0422",
627 (PathSource::Expr(..), true) => "E0423",
628 (PathSource::Expr(..), false) => "E0425",
629 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
630 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
631 (PathSource::TraitItem(..), true) => "E0575",
632 (PathSource::TraitItem(..), false) => "E0576",
633 (PathSource::Visibility, true) => "E0577",
634 (PathSource::Visibility, false) => "E0578",
639 // A minimal representation of a path segment. We use this in resolve because
640 // we synthesize 'path segments' which don't have the rest of an AST or HIR
642 #[derive(Clone, Copy, Debug)]
649 fn from_path(path: &Path) -> Vec<Segment> {
650 path.segments.iter().map(|s| s.into()).collect()
653 fn from_ident(ident: Ident) -> Segment {
660 fn names_to_string(segments: &[Segment]) -> String {
661 names_to_string(&segments.iter()
662 .map(|seg| seg.ident)
663 .collect::<Vec<_>>())
667 impl<'a> From<&'a ast::PathSegment> for Segment {
668 fn from(seg: &'a ast::PathSegment) -> Segment {
676 struct UsePlacementFinder {
677 target_module: NodeId,
682 impl UsePlacementFinder {
683 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
684 let mut finder = UsePlacementFinder {
689 visit::walk_crate(&mut finder, krate);
690 (finder.span, finder.found_use)
694 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
697 module: &'tcx ast::Mod,
699 _: &[ast::Attribute],
702 if self.span.is_some() {
705 if node_id != self.target_module {
706 visit::walk_mod(self, module);
709 // find a use statement
710 for item in &module.items {
712 ItemKind::Use(..) => {
713 // don't suggest placing a use before the prelude
714 // import or other generated ones
715 if item.span.ctxt().outer().expn_info().is_none() {
716 self.span = Some(item.span.shrink_to_lo());
717 self.found_use = true;
721 // don't place use before extern crate
722 ItemKind::ExternCrate(_) => {}
723 // but place them before the first other item
724 _ => if self.span.map_or(true, |span| item.span < span ) {
725 if item.span.ctxt().outer().expn_info().is_none() {
726 // don't insert between attributes and an item
727 if item.attrs.is_empty() {
728 self.span = Some(item.span.shrink_to_lo());
730 // find the first attribute on the item
731 for attr in &item.attrs {
732 if self.span.map_or(true, |span| attr.span < span) {
733 self.span = Some(attr.span.shrink_to_lo());
744 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
745 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
746 fn visit_item(&mut self, item: &'tcx Item) {
747 self.resolve_item(item);
749 fn visit_arm(&mut self, arm: &'tcx Arm) {
750 self.resolve_arm(arm);
752 fn visit_block(&mut self, block: &'tcx Block) {
753 self.resolve_block(block);
755 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
756 debug!("visit_anon_const {:?}", constant);
757 self.with_constant_rib(|this| {
758 visit::walk_anon_const(this, constant);
761 fn visit_expr(&mut self, expr: &'tcx Expr) {
762 self.resolve_expr(expr, None);
764 fn visit_local(&mut self, local: &'tcx Local) {
765 self.resolve_local(local);
767 fn visit_ty(&mut self, ty: &'tcx Ty) {
769 TyKind::Path(ref qself, ref path) => {
770 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
772 TyKind::ImplicitSelf => {
773 let self_ty = keywords::SelfUpper.ident();
774 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
775 .map_or(Def::Err, |d| d.def());
776 self.record_def(ty.id, PathResolution::new(def));
780 visit::walk_ty(self, ty);
782 fn visit_poly_trait_ref(&mut self,
783 tref: &'tcx ast::PolyTraitRef,
784 m: &'tcx ast::TraitBoundModifier) {
785 self.smart_resolve_path(tref.trait_ref.ref_id, None,
786 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
787 visit::walk_poly_trait_ref(self, tref, m);
789 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
790 let generic_params = match foreign_item.node {
791 ForeignItemKind::Fn(_, ref generics) => {
792 HasGenericParams(generics, ItemRibKind)
794 ForeignItemKind::Static(..) => NoGenericParams,
795 ForeignItemKind::Ty => NoGenericParams,
796 ForeignItemKind::Macro(..) => NoGenericParams,
798 self.with_generic_param_rib(generic_params, |this| {
799 visit::walk_foreign_item(this, foreign_item);
802 fn visit_fn(&mut self,
803 function_kind: FnKind<'tcx>,
804 declaration: &'tcx FnDecl,
808 debug!("(resolving function) entering function");
809 let (rib_kind, asyncness) = match function_kind {
810 FnKind::ItemFn(_, ref header, ..) =>
811 (ItemRibKind, header.asyncness),
812 FnKind::Method(_, ref sig, _, _) =>
813 (TraitOrImplItemRibKind, sig.header.asyncness),
814 FnKind::Closure(_) =>
815 // Async closures aren't resolved through `visit_fn`-- they're
816 // processed separately
817 (ClosureRibKind(node_id), IsAsync::NotAsync),
820 // Create a value rib for the function.
821 self.ribs[ValueNS].push(Rib::new(rib_kind));
823 // Create a label rib for the function.
824 self.label_ribs.push(Rib::new(rib_kind));
826 // Add each argument to the rib.
827 let mut bindings_list = FxHashMap::default();
828 for argument in &declaration.inputs {
829 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
831 self.visit_ty(&argument.ty);
833 debug!("(resolving function) recorded argument");
835 visit::walk_fn_ret_ty(self, &declaration.output);
837 // Resolve the function body, potentially inside the body of an async closure
838 if let IsAsync::Async { closure_id, .. } = asyncness {
839 let rib_kind = ClosureRibKind(closure_id);
840 self.ribs[ValueNS].push(Rib::new(rib_kind));
841 self.label_ribs.push(Rib::new(rib_kind));
844 match function_kind {
845 FnKind::ItemFn(.., body) |
846 FnKind::Method(.., body) => {
847 self.visit_block(body);
849 FnKind::Closure(body) => {
850 self.visit_expr(body);
854 // Leave the body of the async closure
855 if asyncness.is_async() {
856 self.label_ribs.pop();
857 self.ribs[ValueNS].pop();
860 debug!("(resolving function) leaving function");
862 self.label_ribs.pop();
863 self.ribs[ValueNS].pop();
866 fn visit_generics(&mut self, generics: &'tcx Generics) {
867 // For type parameter defaults, we have to ban access
868 // to following type parameters, as the Substs can only
869 // provide previous type parameters as they're built. We
870 // put all the parameters on the ban list and then remove
871 // them one by one as they are processed and become available.
872 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
873 let mut found_default = false;
874 default_ban_rib.bindings.extend(generics.params.iter()
875 .filter_map(|param| match param.kind {
876 GenericParamKind::Const { .. } |
877 GenericParamKind::Lifetime { .. } => None,
878 GenericParamKind::Type { ref default, .. } => {
879 found_default |= default.is_some();
881 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
888 for param in &generics.params {
890 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
891 GenericParamKind::Type { ref default, .. } => {
892 for bound in ¶m.bounds {
893 self.visit_param_bound(bound);
896 if let Some(ref ty) = default {
897 self.ribs[TypeNS].push(default_ban_rib);
899 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
902 // Allow all following defaults to refer to this type parameter.
903 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
905 GenericParamKind::Const { ref ty } => {
906 for bound in ¶m.bounds {
907 self.visit_param_bound(bound);
914 for p in &generics.where_clause.predicates {
915 self.visit_where_predicate(p);
920 #[derive(Copy, Clone)]
921 enum GenericParameters<'a, 'b> {
923 HasGenericParams(// Type parameters.
926 // The kind of the rib used for type parameters.
930 /// The rib kind controls the translation of local
931 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
932 #[derive(Copy, Clone, Debug)]
934 /// No translation needs to be applied.
937 /// We passed through a closure scope at the given node ID.
938 /// Translate upvars as appropriate.
939 ClosureRibKind(NodeId /* func id */),
941 /// We passed through an impl or trait and are now in one of its
942 /// methods or associated types. Allow references to ty params that impl or trait
943 /// binds. Disallow any other upvars (including other ty params that are
945 TraitOrImplItemRibKind,
947 /// We passed through an item scope. Disallow upvars.
950 /// We're in a constant item. Can't refer to dynamic stuff.
953 /// We passed through a module.
954 ModuleRibKind(Module<'a>),
956 /// We passed through a `macro_rules!` statement
957 MacroDefinition(DefId),
959 /// All bindings in this rib are type parameters that can't be used
960 /// from the default of a type parameter because they're not declared
961 /// before said type parameter. Also see the `visit_generics` override.
962 ForwardTyParamBanRibKind,
967 /// A rib represents a scope names can live in. Note that these appear in many places, not just
968 /// around braces. At any place where the list of accessible names (of the given namespace)
969 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
970 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
973 /// Different [rib kinds](enum.RibKind) are transparent for different names.
975 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
976 /// resolving, the name is looked up from inside out.
979 bindings: FxHashMap<Ident, Def>,
984 fn new(kind: RibKind<'a>) -> Rib<'a> {
986 bindings: Default::default(),
992 /// An intermediate resolution result.
994 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
995 /// items are visible in their whole block, while defs only from the place they are defined
997 enum LexicalScopeBinding<'a> {
998 Item(&'a NameBinding<'a>),
1002 impl<'a> LexicalScopeBinding<'a> {
1003 fn item(self) -> Option<&'a NameBinding<'a>> {
1005 LexicalScopeBinding::Item(binding) => Some(binding),
1010 fn def(self) -> Def {
1012 LexicalScopeBinding::Item(binding) => binding.def(),
1013 LexicalScopeBinding::Def(def) => def,
1018 #[derive(Copy, Clone, Debug)]
1019 enum ModuleOrUniformRoot<'a> {
1023 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1024 CrateRootAndExternPrelude,
1026 /// Virtual module that denotes resolution in extern prelude.
1027 /// Used for paths starting with `::` on 2018 edition.
1030 /// Virtual module that denotes resolution in current scope.
1031 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1032 /// are always split into two parts, the first of which should be some kind of module.
1036 impl ModuleOrUniformRoot<'_> {
1037 fn same_def(lhs: Self, rhs: Self) -> bool {
1039 (ModuleOrUniformRoot::Module(lhs),
1040 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1041 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1042 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1043 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1044 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1050 #[derive(Clone, Debug)]
1051 enum PathResult<'a> {
1052 Module(ModuleOrUniformRoot<'a>),
1053 NonModule(PathResolution),
1055 Failed(Span, String, bool /* is the error from the last segment? */),
1059 /// An anonymous module, eg. just a block.
1063 /// fn f() {} // (1)
1064 /// { // This is an anonymous module
1065 /// f(); // This resolves to (2) as we are inside the block.
1066 /// fn f() {} // (2)
1068 /// f(); // Resolves to (1)
1072 /// Any module with a name.
1076 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1077 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1082 /// One node in the tree of modules.
1083 pub struct ModuleData<'a> {
1084 parent: Option<Module<'a>>,
1087 // The def id of the closest normal module (`mod`) ancestor (including this module).
1088 normal_ancestor_id: DefId,
1090 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1091 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1092 Option<&'a NameBinding<'a>>)>>,
1093 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1095 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1097 // Macro invocations that can expand into items in this module.
1098 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1100 no_implicit_prelude: bool,
1102 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1103 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1105 // Used to memoize the traits in this module for faster searches through all traits in scope.
1106 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1108 // Whether this module is populated. If not populated, any attempt to
1109 // access the children must be preceded with a
1110 // `populate_module_if_necessary` call.
1111 populated: Cell<bool>,
1113 /// Span of the module itself. Used for error reporting.
1119 type Module<'a> = &'a ModuleData<'a>;
1121 impl<'a> ModuleData<'a> {
1122 fn new(parent: Option<Module<'a>>,
1124 normal_ancestor_id: DefId,
1126 span: Span) -> Self {
1131 resolutions: Default::default(),
1132 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1133 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1134 builtin_attrs: RefCell::new(Vec::new()),
1135 unresolved_invocations: Default::default(),
1136 no_implicit_prelude: false,
1137 glob_importers: RefCell::new(Vec::new()),
1138 globs: RefCell::new(Vec::new()),
1139 traits: RefCell::new(None),
1140 populated: Cell::new(normal_ancestor_id.is_local()),
1146 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1147 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1148 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1152 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1153 let resolutions = self.resolutions.borrow();
1154 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1155 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1156 for &(&(ident, ns), &resolution) in resolutions.iter() {
1157 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1161 fn def(&self) -> Option<Def> {
1163 ModuleKind::Def(def, _) => Some(def),
1168 fn def_id(&self) -> Option<DefId> {
1169 self.def().as_ref().map(Def::def_id)
1172 // `self` resolves to the first module ancestor that `is_normal`.
1173 fn is_normal(&self) -> bool {
1175 ModuleKind::Def(Def::Mod(_), _) => true,
1180 fn is_trait(&self) -> bool {
1182 ModuleKind::Def(Def::Trait(_), _) => true,
1187 fn nearest_item_scope(&'a self) -> Module<'a> {
1188 if self.is_trait() { self.parent.unwrap() } else { self }
1191 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1192 while !ptr::eq(self, other) {
1193 if let Some(parent) = other.parent {
1203 impl<'a> fmt::Debug for ModuleData<'a> {
1204 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1205 write!(f, "{:?}", self.def())
1209 /// Records a possibly-private value, type, or module definition.
1210 #[derive(Clone, Debug)]
1211 pub struct NameBinding<'a> {
1212 kind: NameBindingKind<'a>,
1213 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1216 vis: ty::Visibility,
1219 pub trait ToNameBinding<'a> {
1220 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1223 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1224 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1229 #[derive(Clone, Debug)]
1230 enum NameBindingKind<'a> {
1231 Def(Def, /* is_macro_export */ bool),
1234 binding: &'a NameBinding<'a>,
1235 directive: &'a ImportDirective<'a>,
1240 impl<'a> NameBindingKind<'a> {
1241 /// Is this a name binding of a import?
1242 fn is_import(&self) -> bool {
1244 NameBindingKind::Import { .. } => true,
1250 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1252 struct UseError<'a> {
1253 err: DiagnosticBuilder<'a>,
1254 /// Attach `use` statements for these candidates
1255 candidates: Vec<ImportSuggestion>,
1256 /// The node id of the module to place the use statements in
1258 /// Whether the diagnostic should state that it's "better"
1262 #[derive(Clone, Copy, PartialEq, Debug)]
1263 enum AmbiguityKind {
1268 LegacyHelperVsPrelude,
1273 MoreExpandedVsOuter,
1276 impl AmbiguityKind {
1277 fn descr(self) -> &'static str {
1279 AmbiguityKind::Import =>
1280 "name vs any other name during import resolution",
1281 AmbiguityKind::AbsolutePath =>
1282 "name in the crate root vs extern crate during absolute path resolution",
1283 AmbiguityKind::BuiltinAttr =>
1284 "built-in attribute vs any other name",
1285 AmbiguityKind::DeriveHelper =>
1286 "derive helper attribute vs any other name",
1287 AmbiguityKind::LegacyHelperVsPrelude =>
1288 "legacy plugin helper attribute vs name from prelude",
1289 AmbiguityKind::LegacyVsModern =>
1290 "`macro_rules` vs non-`macro_rules` from other module",
1291 AmbiguityKind::GlobVsOuter =>
1292 "glob import vs any other name from outer scope during import/macro resolution",
1293 AmbiguityKind::GlobVsGlob =>
1294 "glob import vs glob import in the same module",
1295 AmbiguityKind::GlobVsExpanded =>
1296 "glob import vs macro-expanded name in the same \
1297 module during import/macro resolution",
1298 AmbiguityKind::MoreExpandedVsOuter =>
1299 "macro-expanded name vs less macro-expanded name \
1300 from outer scope during import/macro resolution",
1305 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1306 #[derive(Clone, Copy, PartialEq)]
1307 enum AmbiguityErrorMisc {
1314 struct AmbiguityError<'a> {
1315 kind: AmbiguityKind,
1317 b1: &'a NameBinding<'a>,
1318 b2: &'a NameBinding<'a>,
1319 misc1: AmbiguityErrorMisc,
1320 misc2: AmbiguityErrorMisc,
1323 impl<'a> NameBinding<'a> {
1324 fn module(&self) -> Option<Module<'a>> {
1326 NameBindingKind::Module(module) => Some(module),
1327 NameBindingKind::Import { binding, .. } => binding.module(),
1332 fn def(&self) -> Def {
1334 NameBindingKind::Def(def, _) => def,
1335 NameBindingKind::Module(module) => module.def().unwrap(),
1336 NameBindingKind::Import { binding, .. } => binding.def(),
1340 fn is_ambiguity(&self) -> bool {
1341 self.ambiguity.is_some() || match self.kind {
1342 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1347 // We sometimes need to treat variants as `pub` for backwards compatibility
1348 fn pseudo_vis(&self) -> ty::Visibility {
1349 if self.is_variant() && self.def().def_id().is_local() {
1350 ty::Visibility::Public
1356 fn is_variant(&self) -> bool {
1358 NameBindingKind::Def(Def::Variant(..), _) |
1359 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1364 fn is_extern_crate(&self) -> bool {
1366 NameBindingKind::Import {
1367 directive: &ImportDirective {
1368 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1371 NameBindingKind::Module(
1372 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1373 ) => def_id.index == CRATE_DEF_INDEX,
1378 fn is_import(&self) -> bool {
1380 NameBindingKind::Import { .. } => true,
1385 fn is_glob_import(&self) -> bool {
1387 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1392 fn is_importable(&self) -> bool {
1394 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1399 fn is_macro_def(&self) -> bool {
1401 NameBindingKind::Def(Def::Macro(..), _) => true,
1406 fn macro_kind(&self) -> Option<MacroKind> {
1408 Def::Macro(_, kind) => Some(kind),
1409 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1414 fn descr(&self) -> &'static str {
1415 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1418 fn article(&self) -> &'static str {
1419 if self.is_extern_crate() { "an" } else { self.def().article() }
1422 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1423 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1424 // Then this function returns `true` if `self` may emerge from a macro *after* that
1425 // in some later round and screw up our previously found resolution.
1426 // See more detailed explanation in
1427 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1428 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1429 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1430 // Expansions are partially ordered, so "may appear after" is an inversion of
1431 // "certainly appears before or simultaneously" and includes unordered cases.
1432 let self_parent_expansion = self.expansion;
1433 let other_parent_expansion = binding.expansion;
1434 let certainly_before_other_or_simultaneously =
1435 other_parent_expansion.is_descendant_of(self_parent_expansion);
1436 let certainly_before_invoc_or_simultaneously =
1437 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1438 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1442 /// Interns the names of the primitive types.
1444 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1445 /// special handling, since they have no place of origin.
1447 struct PrimitiveTypeTable {
1448 primitive_types: FxHashMap<Name, PrimTy>,
1451 impl PrimitiveTypeTable {
1452 fn new() -> PrimitiveTypeTable {
1453 let mut table = PrimitiveTypeTable::default();
1455 table.intern("bool", Bool);
1456 table.intern("char", Char);
1457 table.intern("f32", Float(FloatTy::F32));
1458 table.intern("f64", Float(FloatTy::F64));
1459 table.intern("isize", Int(IntTy::Isize));
1460 table.intern("i8", Int(IntTy::I8));
1461 table.intern("i16", Int(IntTy::I16));
1462 table.intern("i32", Int(IntTy::I32));
1463 table.intern("i64", Int(IntTy::I64));
1464 table.intern("i128", Int(IntTy::I128));
1465 table.intern("str", Str);
1466 table.intern("usize", Uint(UintTy::Usize));
1467 table.intern("u8", Uint(UintTy::U8));
1468 table.intern("u16", Uint(UintTy::U16));
1469 table.intern("u32", Uint(UintTy::U32));
1470 table.intern("u64", Uint(UintTy::U64));
1471 table.intern("u128", Uint(UintTy::U128));
1475 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1476 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1480 #[derive(Debug, Default, Clone)]
1481 pub struct ExternPreludeEntry<'a> {
1482 extern_crate_item: Option<&'a NameBinding<'a>>,
1483 pub introduced_by_item: bool,
1486 /// The main resolver class.
1488 /// This is the visitor that walks the whole crate.
1489 pub struct Resolver<'a> {
1490 session: &'a Session,
1493 pub definitions: Definitions,
1495 graph_root: Module<'a>,
1497 prelude: Option<Module<'a>>,
1498 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1500 /// n.b. This is used only for better diagnostics, not name resolution itself.
1501 has_self: FxHashSet<DefId>,
1503 /// Names of fields of an item `DefId` accessible with dot syntax.
1504 /// Used for hints during error reporting.
1505 field_names: FxHashMap<DefId, Vec<Name>>,
1507 /// All imports known to succeed or fail.
1508 determined_imports: Vec<&'a ImportDirective<'a>>,
1510 /// All non-determined imports.
1511 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1513 /// The module that represents the current item scope.
1514 current_module: Module<'a>,
1516 /// The current set of local scopes for types and values.
1517 /// FIXME #4948: Reuse ribs to avoid allocation.
1518 ribs: PerNS<Vec<Rib<'a>>>,
1520 /// The current set of local scopes, for labels.
1521 label_ribs: Vec<Rib<'a>>,
1523 /// The trait that the current context can refer to.
1524 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1526 /// The current self type if inside an impl (used for better errors).
1527 current_self_type: Option<Ty>,
1529 /// The current self item if inside an ADT (used for better errors).
1530 current_self_item: Option<NodeId>,
1532 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1533 /// We are resolving a last import segment during import validation.
1534 last_import_segment: bool,
1535 /// This binding should be ignored during in-module resolution, so that we don't get
1536 /// "self-confirming" import resolutions during import validation.
1537 blacklisted_binding: Option<&'a NameBinding<'a>>,
1539 /// The idents for the primitive types.
1540 primitive_type_table: PrimitiveTypeTable,
1543 import_map: ImportMap,
1544 pub freevars: FreevarMap,
1545 freevars_seen: NodeMap<NodeMap<usize>>,
1546 pub export_map: ExportMap,
1547 pub trait_map: TraitMap,
1549 /// A map from nodes to anonymous modules.
1550 /// Anonymous modules are pseudo-modules that are implicitly created around items
1551 /// contained within blocks.
1553 /// For example, if we have this:
1561 /// There will be an anonymous module created around `g` with the ID of the
1562 /// entry block for `f`.
1563 block_map: NodeMap<Module<'a>>,
1564 module_map: FxHashMap<DefId, Module<'a>>,
1565 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1566 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1568 /// Maps glob imports to the names of items actually imported.
1569 pub glob_map: GlobMap,
1571 used_imports: FxHashSet<(NodeId, Namespace)>,
1572 pub maybe_unused_trait_imports: NodeSet,
1573 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1575 /// A list of labels as of yet unused. Labels will be removed from this map when
1576 /// they are used (in a `break` or `continue` statement)
1577 pub unused_labels: FxHashMap<NodeId, Span>,
1579 /// privacy errors are delayed until the end in order to deduplicate them
1580 privacy_errors: Vec<PrivacyError<'a>>,
1581 /// ambiguity errors are delayed for deduplication
1582 ambiguity_errors: Vec<AmbiguityError<'a>>,
1583 /// `use` injections are delayed for better placement and deduplication
1584 use_injections: Vec<UseError<'a>>,
1585 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1586 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1588 arenas: &'a ResolverArenas<'a>,
1589 dummy_binding: &'a NameBinding<'a>,
1591 crate_loader: &'a mut CrateLoader<'a>,
1592 macro_names: FxHashSet<Ident>,
1593 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1594 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1595 pub all_macros: FxHashMap<Name, Def>,
1596 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1597 macro_defs: FxHashMap<Mark, DefId>,
1598 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1600 /// List of crate local macros that we need to warn about as being unused.
1601 /// Right now this only includes macro_rules! macros, and macros 2.0.
1602 unused_macros: FxHashSet<DefId>,
1604 /// Maps the `Mark` of an expansion to its containing module or block.
1605 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1607 /// Avoid duplicated errors for "name already defined".
1608 name_already_seen: FxHashMap<Name, Span>,
1610 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1612 /// This table maps struct IDs into struct constructor IDs,
1613 /// it's not used during normal resolution, only for better error reporting.
1614 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1616 /// Only used for better errors on `fn(): fn()`
1617 current_type_ascription: Vec<Span>,
1619 injected_crate: Option<Module<'a>>,
1622 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1624 pub struct ResolverArenas<'a> {
1625 modules: arena::TypedArena<ModuleData<'a>>,
1626 local_modules: RefCell<Vec<Module<'a>>>,
1627 name_bindings: arena::TypedArena<NameBinding<'a>>,
1628 import_directives: arena::TypedArena<ImportDirective<'a>>,
1629 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1630 invocation_data: arena::TypedArena<InvocationData<'a>>,
1631 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1634 impl<'a> ResolverArenas<'a> {
1635 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1636 let module = self.modules.alloc(module);
1637 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1638 self.local_modules.borrow_mut().push(module);
1642 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1643 self.local_modules.borrow()
1645 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1646 self.name_bindings.alloc(name_binding)
1648 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1649 -> &'a ImportDirective<'_> {
1650 self.import_directives.alloc(import_directive)
1652 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1653 self.name_resolutions.alloc(Default::default())
1655 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1656 -> &'a InvocationData<'a> {
1657 self.invocation_data.alloc(expansion_data)
1659 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1660 self.legacy_bindings.alloc(binding)
1664 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1665 fn parent(self, id: DefId) -> Option<DefId> {
1667 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1668 _ => self.cstore.def_key(id).parent,
1669 }.map(|index| DefId { index, ..id })
1673 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1674 /// the resolver is no longer needed as all the relevant information is inline.
1675 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1676 fn resolve_hir_path(
1681 self.resolve_hir_path_cb(path, is_value,
1682 |resolver, span, error| resolve_error(resolver, span, error))
1685 fn resolve_str_path(
1688 crate_root: Option<&str>,
1689 components: &[&str],
1692 let segments = iter::once(keywords::PathRoot.ident())
1694 crate_root.into_iter()
1695 .chain(components.iter().cloned())
1696 .map(Ident::from_str)
1697 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1700 let path = ast::Path {
1705 self.resolve_hir_path(&path, is_value)
1708 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1709 self.def_map.get(&id).cloned()
1712 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1713 self.import_map.get(&id).cloned().unwrap_or_default()
1716 fn definitions(&mut self) -> &mut Definitions {
1717 &mut self.definitions
1721 impl<'a> Resolver<'a> {
1722 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1723 /// isn't something that can be returned because it can't be made to live that long,
1724 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1725 /// just that an error occurred.
1726 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1727 -> Result<hir::Path, ()> {
1729 let mut errored = false;
1731 let path = if path_str.starts_with("::") {
1734 segments: iter::once(keywords::PathRoot.ident())
1736 path_str.split("::").skip(1).map(Ident::from_str)
1738 .map(|i| self.new_ast_path_segment(i))
1746 .map(Ident::from_str)
1747 .map(|i| self.new_ast_path_segment(i))
1751 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1752 if errored || path.def == Def::Err {
1759 /// resolve_hir_path, but takes a callback in case there was an error
1760 fn resolve_hir_path_cb<F>(
1766 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1768 let namespace = if is_value { ValueNS } else { TypeNS };
1769 let span = path.span;
1770 let segments = &path.segments;
1771 let path = Segment::from_path(&path);
1772 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1773 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1774 span, CrateLint::No) {
1775 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1776 module.def().unwrap(),
1777 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1778 path_res.base_def(),
1779 PathResult::NonModule(..) => {
1780 let msg = "type-relative paths are not supported in this context";
1781 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1784 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1785 PathResult::Failed(span, msg, _) => {
1786 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1791 let segments: Vec<_> = segments.iter().map(|seg| {
1792 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1793 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1799 segments: segments.into(),
1803 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1804 let mut seg = ast::PathSegment::from_ident(ident);
1805 seg.id = self.session.next_node_id();
1810 impl<'a> Resolver<'a> {
1811 pub fn new(session: &'a Session,
1815 crate_loader: &'a mut CrateLoader<'a>,
1816 arenas: &'a ResolverArenas<'a>)
1818 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1819 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1820 let graph_root = arenas.alloc_module(ModuleData {
1821 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1822 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1824 let mut module_map = FxHashMap::default();
1825 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1827 let mut definitions = Definitions::new();
1828 DefCollector::new(&mut definitions, Mark::root())
1829 .collect_root(crate_name, session.local_crate_disambiguator());
1831 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1832 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1835 if !attr::contains_name(&krate.attrs, "no_core") {
1836 extern_prelude.insert(Ident::from_str("core"), Default::default());
1837 if !attr::contains_name(&krate.attrs, "no_std") {
1838 extern_prelude.insert(Ident::from_str("std"), Default::default());
1839 if session.rust_2018() {
1840 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1845 let mut invocations = FxHashMap::default();
1846 invocations.insert(Mark::root(),
1847 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1849 let mut macro_defs = FxHashMap::default();
1850 macro_defs.insert(Mark::root(), root_def_id);
1859 // The outermost module has def ID 0; this is not reflected in the
1865 has_self: FxHashSet::default(),
1866 field_names: FxHashMap::default(),
1868 determined_imports: Vec::new(),
1869 indeterminate_imports: Vec::new(),
1871 current_module: graph_root,
1873 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1874 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1875 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1877 label_ribs: Vec::new(),
1879 current_trait_ref: None,
1880 current_self_type: None,
1881 current_self_item: None,
1882 last_import_segment: false,
1883 blacklisted_binding: None,
1885 primitive_type_table: PrimitiveTypeTable::new(),
1887 def_map: Default::default(),
1888 import_map: Default::default(),
1889 freevars: Default::default(),
1890 freevars_seen: Default::default(),
1891 export_map: FxHashMap::default(),
1892 trait_map: Default::default(),
1894 block_map: Default::default(),
1895 extern_module_map: FxHashMap::default(),
1896 binding_parent_modules: FxHashMap::default(),
1898 glob_map: Default::default(),
1900 used_imports: FxHashSet::default(),
1901 maybe_unused_trait_imports: Default::default(),
1902 maybe_unused_extern_crates: Vec::new(),
1904 unused_labels: FxHashMap::default(),
1906 privacy_errors: Vec::new(),
1907 ambiguity_errors: Vec::new(),
1908 use_injections: Vec::new(),
1909 macro_expanded_macro_export_errors: BTreeSet::new(),
1912 dummy_binding: arenas.alloc_name_binding(NameBinding {
1913 kind: NameBindingKind::Def(Def::Err, false),
1915 expansion: Mark::root(),
1917 vis: ty::Visibility::Public,
1921 macro_names: FxHashSet::default(),
1922 builtin_macros: FxHashMap::default(),
1923 macro_use_prelude: FxHashMap::default(),
1924 all_macros: FxHashMap::default(),
1925 macro_map: FxHashMap::default(),
1928 local_macro_def_scopes: FxHashMap::default(),
1929 name_already_seen: FxHashMap::default(),
1930 potentially_unused_imports: Vec::new(),
1931 struct_constructors: Default::default(),
1932 unused_macros: FxHashSet::default(),
1933 current_type_ascription: Vec::new(),
1934 injected_crate: None,
1938 pub fn arenas() -> ResolverArenas<'a> {
1942 /// Runs the function on each namespace.
1943 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1949 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1951 match self.macro_defs.get(&ctxt.outer()) {
1952 Some(&def_id) => return def_id,
1953 None => ctxt.remove_mark(),
1958 /// Entry point to crate resolution.
1959 pub fn resolve_crate(&mut self, krate: &Crate) {
1960 ImportResolver { resolver: self }.finalize_imports();
1961 self.current_module = self.graph_root;
1962 self.finalize_current_module_macro_resolutions();
1964 visit::walk_crate(self, krate);
1966 check_unused::check_crate(self, krate);
1967 self.report_errors(krate);
1968 self.crate_loader.postprocess(krate);
1975 normal_ancestor_id: DefId,
1979 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1980 self.arenas.alloc_module(module)
1983 fn record_use(&mut self, ident: Ident, ns: Namespace,
1984 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1985 if let Some((b2, kind)) = used_binding.ambiguity {
1986 self.ambiguity_errors.push(AmbiguityError {
1987 kind, ident, b1: used_binding, b2,
1988 misc1: AmbiguityErrorMisc::None,
1989 misc2: AmbiguityErrorMisc::None,
1992 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1993 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1994 // but not introduce it, as used if they are accessed from lexical scope.
1995 if is_lexical_scope {
1996 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1997 if let Some(crate_item) = entry.extern_crate_item {
1998 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2005 directive.used.set(true);
2006 self.used_imports.insert((directive.id, ns));
2007 self.add_to_glob_map(&directive, ident);
2008 self.record_use(ident, ns, binding, false);
2013 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2014 if directive.is_glob() {
2015 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2019 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2020 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2021 /// `ident` in the first scope that defines it (or None if no scopes define it).
2023 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2024 /// the items are defined in the block. For example,
2027 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2030 /// g(); // This resolves to the local variable `g` since it shadows the item.
2034 /// Invariant: This must only be called during main resolution, not during
2035 /// import resolution.
2036 fn resolve_ident_in_lexical_scope(&mut self,
2039 record_used_id: Option<NodeId>,
2041 -> Option<LexicalScopeBinding<'a>> {
2042 assert!(ns == TypeNS || ns == ValueNS);
2043 if ident.name == keywords::Invalid.name() {
2044 return Some(LexicalScopeBinding::Def(Def::Err));
2046 ident.span = if ident.name == keywords::SelfUpper.name() {
2047 // FIXME(jseyfried) improve `Self` hygiene
2048 ident.span.with_ctxt(SyntaxContext::empty())
2049 } else if ns == TypeNS {
2052 ident.span.modern_and_legacy()
2055 // Walk backwards up the ribs in scope.
2056 let record_used = record_used_id.is_some();
2057 let mut module = self.graph_root;
2058 for i in (0 .. self.ribs[ns].len()).rev() {
2059 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2060 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2061 // The ident resolves to a type parameter or local variable.
2062 return Some(LexicalScopeBinding::Def(
2063 self.adjust_local_def(ns, i, def, record_used, path_span)
2067 module = match self.ribs[ns][i].kind {
2068 ModuleRibKind(module) => module,
2069 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2070 // If an invocation of this macro created `ident`, give up on `ident`
2071 // and switch to `ident`'s source from the macro definition.
2072 ident.span.remove_mark();
2078 let item = self.resolve_ident_in_module_unadjusted(
2079 ModuleOrUniformRoot::Module(module),
2085 if let Ok(binding) = item {
2086 // The ident resolves to an item.
2087 return Some(LexicalScopeBinding::Item(binding));
2091 ModuleKind::Block(..) => {}, // We can see through blocks
2096 ident.span = ident.span.modern();
2097 let mut poisoned = None;
2099 let opt_module = if let Some(node_id) = record_used_id {
2100 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2101 node_id, &mut poisoned)
2103 self.hygienic_lexical_parent(module, &mut ident.span)
2105 module = unwrap_or!(opt_module, break);
2106 let orig_current_module = self.current_module;
2107 self.current_module = module; // Lexical resolutions can never be a privacy error.
2108 let result = self.resolve_ident_in_module_unadjusted(
2109 ModuleOrUniformRoot::Module(module),
2115 self.current_module = orig_current_module;
2119 if let Some(node_id) = poisoned {
2120 self.session.buffer_lint_with_diagnostic(
2121 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2122 node_id, ident.span,
2123 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2124 lint::builtin::BuiltinLintDiagnostics::
2125 ProcMacroDeriveResolutionFallback(ident.span),
2128 return Some(LexicalScopeBinding::Item(binding))
2130 Err(Determined) => continue,
2131 Err(Undetermined) =>
2132 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2136 if !module.no_implicit_prelude {
2138 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2139 return Some(LexicalScopeBinding::Item(binding));
2142 if ns == TypeNS && is_known_tool(ident.name) {
2143 let binding = (Def::ToolMod, ty::Visibility::Public,
2144 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2145 return Some(LexicalScopeBinding::Item(binding));
2147 if let Some(prelude) = self.prelude {
2148 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2149 ModuleOrUniformRoot::Module(prelude),
2155 return Some(LexicalScopeBinding::Item(binding));
2163 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2164 -> Option<Module<'a>> {
2165 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2166 return Some(self.macro_def_scope(span.remove_mark()));
2169 if let ModuleKind::Block(..) = module.kind {
2170 return Some(module.parent.unwrap());
2176 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2177 span: &mut Span, node_id: NodeId,
2178 poisoned: &mut Option<NodeId>)
2179 -> Option<Module<'a>> {
2180 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2184 // We need to support the next case under a deprecation warning
2187 // ---- begin: this comes from a proc macro derive
2188 // mod implementation_details {
2189 // // Note that `MyStruct` is not in scope here.
2190 // impl SomeTrait for MyStruct { ... }
2194 // So we have to fall back to the module's parent during lexical resolution in this case.
2195 if let Some(parent) = module.parent {
2196 // Inner module is inside the macro, parent module is outside of the macro.
2197 if module.expansion != parent.expansion &&
2198 module.expansion.is_descendant_of(parent.expansion) {
2199 // The macro is a proc macro derive
2200 if module.expansion.looks_like_proc_macro_derive() {
2201 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2202 *poisoned = Some(node_id);
2203 return module.parent;
2212 fn resolve_ident_in_module(
2214 module: ModuleOrUniformRoot<'a>,
2217 parent_scope: Option<&ParentScope<'a>>,
2220 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2221 self.resolve_ident_in_module_ext(
2222 module, ident, ns, parent_scope, record_used, path_span
2223 ).map_err(|(determinacy, _)| determinacy)
2226 fn resolve_ident_in_module_ext(
2228 module: ModuleOrUniformRoot<'a>,
2231 parent_scope: Option<&ParentScope<'a>>,
2234 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2235 let orig_current_module = self.current_module;
2237 ModuleOrUniformRoot::Module(module) => {
2238 ident.span = ident.span.modern();
2239 if let Some(def) = ident.span.adjust(module.expansion) {
2240 self.current_module = self.macro_def_scope(def);
2243 ModuleOrUniformRoot::ExternPrelude => {
2244 ident.span = ident.span.modern();
2245 ident.span.adjust(Mark::root());
2247 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2248 ModuleOrUniformRoot::CurrentScope => {
2252 let result = self.resolve_ident_in_module_unadjusted_ext(
2253 module, ident, ns, parent_scope, false, record_used, path_span,
2255 self.current_module = orig_current_module;
2259 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2260 let mut ctxt = ident.span.ctxt();
2261 let mark = if ident.name == keywords::DollarCrate.name() {
2262 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2263 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2264 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2265 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2266 // definitions actually produced by `macro` and `macro` definitions produced by
2267 // `macro_rules!`, but at least such configurations are not stable yet.
2268 ctxt = ctxt.modern_and_legacy();
2269 let mut iter = ctxt.marks().into_iter().rev().peekable();
2270 let mut result = None;
2271 // Find the last modern mark from the end if it exists.
2272 while let Some(&(mark, transparency)) = iter.peek() {
2273 if transparency == Transparency::Opaque {
2274 result = Some(mark);
2280 // Then find the last legacy mark from the end if it exists.
2281 for (mark, transparency) in iter {
2282 if transparency == Transparency::SemiTransparent {
2283 result = Some(mark);
2290 ctxt = ctxt.modern();
2291 ctxt.adjust(Mark::root())
2293 let module = match mark {
2294 Some(def) => self.macro_def_scope(def),
2295 None => return self.graph_root,
2297 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2300 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2301 let mut module = self.get_module(module.normal_ancestor_id);
2302 while module.span.ctxt().modern() != *ctxt {
2303 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2304 module = self.get_module(parent.normal_ancestor_id);
2311 // We maintain a list of value ribs and type ribs.
2313 // Simultaneously, we keep track of the current position in the module
2314 // graph in the `current_module` pointer. When we go to resolve a name in
2315 // the value or type namespaces, we first look through all the ribs and
2316 // then query the module graph. When we resolve a name in the module
2317 // namespace, we can skip all the ribs (since nested modules are not
2318 // allowed within blocks in Rust) and jump straight to the current module
2321 // Named implementations are handled separately. When we find a method
2322 // call, we consult the module node to find all of the implementations in
2323 // scope. This information is lazily cached in the module node. We then
2324 // generate a fake "implementation scope" containing all the
2325 // implementations thus found, for compatibility with old resolve pass.
2327 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2328 where F: FnOnce(&mut Resolver<'_>) -> T
2330 let id = self.definitions.local_def_id(id);
2331 let module = self.module_map.get(&id).cloned(); // clones a reference
2332 if let Some(module) = module {
2333 // Move down in the graph.
2334 let orig_module = replace(&mut self.current_module, module);
2335 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2336 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2338 self.finalize_current_module_macro_resolutions();
2341 self.current_module = orig_module;
2342 self.ribs[ValueNS].pop();
2343 self.ribs[TypeNS].pop();
2350 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2351 /// is returned by the given predicate function
2353 /// Stops after meeting a closure.
2354 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2355 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2357 for rib in self.label_ribs.iter().rev() {
2360 // If an invocation of this macro created `ident`, give up on `ident`
2361 // and switch to `ident`'s source from the macro definition.
2362 MacroDefinition(def) => {
2363 if def == self.macro_def(ident.span.ctxt()) {
2364 ident.span.remove_mark();
2368 // Do not resolve labels across function boundary
2372 let r = pred(rib, ident);
2380 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2381 debug!("resolve_adt");
2382 self.with_current_self_item(item, |this| {
2383 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2384 let item_def_id = this.definitions.local_def_id(item.id);
2385 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2386 visit::walk_item(this, item);
2392 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2393 let segments = &use_tree.prefix.segments;
2394 if !segments.is_empty() {
2395 let ident = segments[0].ident;
2396 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2400 let nss = match use_tree.kind {
2401 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2404 let report_error = |this: &Self, ns| {
2405 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2406 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2410 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2411 Some(LexicalScopeBinding::Def(..)) => {
2412 report_error(self, ns);
2414 Some(LexicalScopeBinding::Item(binding)) => {
2415 let orig_blacklisted_binding =
2416 mem::replace(&mut self.blacklisted_binding, Some(binding));
2417 if let Some(LexicalScopeBinding::Def(..)) =
2418 self.resolve_ident_in_lexical_scope(ident, ns, None,
2419 use_tree.prefix.span) {
2420 report_error(self, ns);
2422 self.blacklisted_binding = orig_blacklisted_binding;
2427 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2428 for (use_tree, _) in use_trees {
2429 self.future_proof_import(use_tree);
2434 fn resolve_item(&mut self, item: &Item) {
2435 let name = item.ident.name;
2436 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2439 ItemKind::Ty(_, ref generics) |
2440 ItemKind::Fn(_, _, ref generics, _) |
2441 ItemKind::Existential(_, ref generics) => {
2442 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2443 |this| visit::walk_item(this, item));
2446 ItemKind::Enum(_, ref generics) |
2447 ItemKind::Struct(_, ref generics) |
2448 ItemKind::Union(_, ref generics) => {
2449 self.resolve_adt(item, generics);
2452 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2453 self.resolve_implementation(generics,
2459 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2460 // Create a new rib for the trait-wide type parameters.
2461 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2462 let local_def_id = this.definitions.local_def_id(item.id);
2463 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2464 this.visit_generics(generics);
2465 walk_list!(this, visit_param_bound, bounds);
2467 for trait_item in trait_items {
2468 let generic_params = HasGenericParams(&trait_item.generics,
2469 TraitOrImplItemRibKind);
2470 this.with_generic_param_rib(generic_params, |this| {
2471 match trait_item.node {
2472 TraitItemKind::Const(ref ty, ref default) => {
2475 // Only impose the restrictions of
2476 // ConstRibKind for an actual constant
2477 // expression in a provided default.
2478 if let Some(ref expr) = *default{
2479 this.with_constant_rib(|this| {
2480 this.visit_expr(expr);
2484 TraitItemKind::Method(_, _) => {
2485 visit::walk_trait_item(this, trait_item)
2487 TraitItemKind::Type(..) => {
2488 visit::walk_trait_item(this, trait_item)
2490 TraitItemKind::Macro(_) => {
2491 panic!("unexpanded macro in resolve!")
2500 ItemKind::TraitAlias(ref generics, ref bounds) => {
2501 // Create a new rib for the trait-wide type parameters.
2502 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2503 let local_def_id = this.definitions.local_def_id(item.id);
2504 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2505 this.visit_generics(generics);
2506 walk_list!(this, visit_param_bound, bounds);
2511 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2512 self.with_scope(item.id, |this| {
2513 visit::walk_item(this, item);
2517 ItemKind::Static(ref ty, _, ref expr) |
2518 ItemKind::Const(ref ty, ref expr) => {
2519 debug!("resolve_item ItemKind::Const");
2520 self.with_item_rib(|this| {
2522 this.with_constant_rib(|this| {
2523 this.visit_expr(expr);
2528 ItemKind::Use(ref use_tree) => {
2529 self.future_proof_import(use_tree);
2532 ItemKind::ExternCrate(..) |
2533 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2534 // do nothing, these are just around to be encoded
2537 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2541 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2542 where F: FnOnce(&mut Resolver<'_>)
2544 debug!("with_generic_param_rib");
2545 match generic_params {
2546 HasGenericParams(generics, rib_kind) => {
2547 let mut function_type_rib = Rib::new(rib_kind);
2548 let mut function_value_rib = Rib::new(rib_kind);
2549 let mut seen_bindings = FxHashMap::default();
2550 for param in &generics.params {
2552 GenericParamKind::Lifetime { .. } => {}
2553 GenericParamKind::Type { .. } => {
2554 let ident = param.ident.modern();
2555 debug!("with_generic_param_rib: {}", param.id);
2557 if seen_bindings.contains_key(&ident) {
2558 let span = seen_bindings.get(&ident).unwrap();
2559 let err = ResolutionError::NameAlreadyUsedInParameterList(
2563 resolve_error(self, param.ident.span, err);
2565 seen_bindings.entry(ident).or_insert(param.ident.span);
2567 // Plain insert (no renaming).
2568 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2569 function_type_rib.bindings.insert(ident, def);
2570 self.record_def(param.id, PathResolution::new(def));
2572 GenericParamKind::Const { .. } => {
2573 let ident = param.ident.modern();
2574 debug!("with_generic_param_rib: {}", param.id);
2576 if seen_bindings.contains_key(&ident) {
2577 let span = seen_bindings.get(&ident).unwrap();
2578 let err = ResolutionError::NameAlreadyUsedInParameterList(
2582 resolve_error(self, param.ident.span, err);
2584 seen_bindings.entry(ident).or_insert(param.ident.span);
2586 let def = Def::ConstParam(self.definitions.local_def_id(param.id));
2587 function_value_rib.bindings.insert(ident, def);
2588 self.record_def(param.id, PathResolution::new(def));
2592 self.ribs[ValueNS].push(function_value_rib);
2593 self.ribs[TypeNS].push(function_type_rib);
2596 NoGenericParams => {
2603 if let HasGenericParams(..) = generic_params {
2604 self.ribs[TypeNS].pop();
2605 self.ribs[ValueNS].pop();
2609 fn with_label_rib<F>(&mut self, f: F)
2610 where F: FnOnce(&mut Resolver<'_>)
2612 self.label_ribs.push(Rib::new(NormalRibKind));
2614 self.label_ribs.pop();
2617 fn with_item_rib<F>(&mut self, f: F)
2618 where F: FnOnce(&mut Resolver<'_>)
2620 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2621 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2623 self.ribs[TypeNS].pop();
2624 self.ribs[ValueNS].pop();
2627 fn with_constant_rib<F>(&mut self, f: F)
2628 where F: FnOnce(&mut Resolver<'_>)
2630 debug!("with_constant_rib");
2631 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2632 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2634 self.label_ribs.pop();
2635 self.ribs[ValueNS].pop();
2638 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2639 where F: FnOnce(&mut Resolver<'_>) -> T
2641 // Handle nested impls (inside fn bodies)
2642 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2643 let result = f(self);
2644 self.current_self_type = previous_value;
2648 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2649 where F: FnOnce(&mut Resolver<'_>) -> T
2651 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2652 let result = f(self);
2653 self.current_self_item = previous_value;
2657 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2658 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2659 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2661 let mut new_val = None;
2662 let mut new_id = None;
2663 if let Some(trait_ref) = opt_trait_ref {
2664 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2665 let def = self.smart_resolve_path_fragment(
2669 trait_ref.path.span,
2670 PathSource::Trait(AliasPossibility::No),
2671 CrateLint::SimplePath(trait_ref.ref_id),
2673 if def != Def::Err {
2674 new_id = Some(def.def_id());
2675 let span = trait_ref.path.span;
2676 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2677 self.resolve_path_without_parent_scope(
2682 CrateLint::SimplePath(trait_ref.ref_id),
2685 new_val = Some((module, trait_ref.clone()));
2689 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2690 let result = f(self, new_id);
2691 self.current_trait_ref = original_trait_ref;
2695 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2696 where F: FnOnce(&mut Resolver<'_>)
2698 let mut self_type_rib = Rib::new(NormalRibKind);
2700 // plain insert (no renaming, types are not currently hygienic....)
2701 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2702 self.ribs[TypeNS].push(self_type_rib);
2704 self.ribs[TypeNS].pop();
2707 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2708 where F: FnOnce(&mut Resolver<'_>)
2710 let self_def = Def::SelfCtor(impl_id);
2711 let mut self_type_rib = Rib::new(NormalRibKind);
2712 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2713 self.ribs[ValueNS].push(self_type_rib);
2715 self.ribs[ValueNS].pop();
2718 fn resolve_implementation(&mut self,
2719 generics: &Generics,
2720 opt_trait_reference: &Option<TraitRef>,
2723 impl_items: &[ImplItem]) {
2724 debug!("resolve_implementation");
2725 // If applicable, create a rib for the type parameters.
2726 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2727 // Dummy self type for better errors if `Self` is used in the trait path.
2728 this.with_self_rib(Def::SelfTy(None, None), |this| {
2729 // Resolve the trait reference, if necessary.
2730 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2731 let item_def_id = this.definitions.local_def_id(item_id);
2732 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2733 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2734 // Resolve type arguments in the trait path.
2735 visit::walk_trait_ref(this, trait_ref);
2737 // Resolve the self type.
2738 this.visit_ty(self_type);
2739 // Resolve the generic parameters.
2740 this.visit_generics(generics);
2741 // Resolve the items within the impl.
2742 this.with_current_self_type(self_type, |this| {
2743 this.with_self_struct_ctor_rib(item_def_id, |this| {
2744 debug!("resolve_implementation with_self_struct_ctor_rib");
2745 for impl_item in impl_items {
2746 this.resolve_visibility(&impl_item.vis);
2748 // We also need a new scope for the impl item type parameters.
2749 let generic_params = HasGenericParams(&impl_item.generics,
2750 TraitOrImplItemRibKind);
2751 this.with_generic_param_rib(generic_params, |this| {
2752 use self::ResolutionError::*;
2753 match impl_item.node {
2754 ImplItemKind::Const(..) => {
2756 "resolve_implementation ImplItemKind::Const",
2758 // If this is a trait impl, ensure the const
2760 this.check_trait_item(
2764 |n, s| ConstNotMemberOfTrait(n, s),
2767 this.with_constant_rib(|this| {
2768 visit::walk_impl_item(this, impl_item)
2771 ImplItemKind::Method(..) => {
2772 // If this is a trait impl, ensure the method
2774 this.check_trait_item(impl_item.ident,
2777 |n, s| MethodNotMemberOfTrait(n, s));
2779 visit::walk_impl_item(this, impl_item);
2781 ImplItemKind::Type(ref ty) => {
2782 // If this is a trait impl, ensure the type
2784 this.check_trait_item(impl_item.ident,
2787 |n, s| TypeNotMemberOfTrait(n, s));
2791 ImplItemKind::Existential(ref bounds) => {
2792 // If this is a trait impl, ensure the type
2794 this.check_trait_item(impl_item.ident,
2797 |n, s| TypeNotMemberOfTrait(n, s));
2799 for bound in bounds {
2800 this.visit_param_bound(bound);
2803 ImplItemKind::Macro(_) =>
2804 panic!("unexpanded macro in resolve!"),
2816 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2817 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2819 // If there is a TraitRef in scope for an impl, then the method must be in the
2821 if let Some((module, _)) = self.current_trait_ref {
2822 if self.resolve_ident_in_module(
2823 ModuleOrUniformRoot::Module(module),
2830 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2831 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2836 fn resolve_local(&mut self, local: &Local) {
2837 // Resolve the type.
2838 walk_list!(self, visit_ty, &local.ty);
2840 // Resolve the initializer.
2841 walk_list!(self, visit_expr, &local.init);
2843 // Resolve the pattern.
2844 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2847 // build a map from pattern identifiers to binding-info's.
2848 // this is done hygienically. This could arise for a macro
2849 // that expands into an or-pattern where one 'x' was from the
2850 // user and one 'x' came from the macro.
2851 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2852 let mut binding_map = FxHashMap::default();
2854 pat.walk(&mut |pat| {
2855 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2856 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2857 Some(Def::Local(..)) => true,
2860 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2861 binding_map.insert(ident, binding_info);
2870 // check that all of the arms in an or-pattern have exactly the
2871 // same set of bindings, with the same binding modes for each.
2872 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2873 if pats.is_empty() {
2877 let mut missing_vars = FxHashMap::default();
2878 let mut inconsistent_vars = FxHashMap::default();
2879 for (i, p) in pats.iter().enumerate() {
2880 let map_i = self.binding_mode_map(&p);
2882 for (j, q) in pats.iter().enumerate() {
2887 let map_j = self.binding_mode_map(&q);
2888 for (&key, &binding_i) in &map_i {
2889 if map_j.is_empty() { // Account for missing bindings when
2890 let binding_error = missing_vars // map_j has none.
2892 .or_insert(BindingError {
2894 origin: BTreeSet::new(),
2895 target: BTreeSet::new(),
2897 binding_error.origin.insert(binding_i.span);
2898 binding_error.target.insert(q.span);
2900 for (&key_j, &binding_j) in &map_j {
2901 match map_i.get(&key_j) {
2902 None => { // missing binding
2903 let binding_error = missing_vars
2905 .or_insert(BindingError {
2907 origin: BTreeSet::new(),
2908 target: BTreeSet::new(),
2910 binding_error.origin.insert(binding_j.span);
2911 binding_error.target.insert(p.span);
2913 Some(binding_i) => { // check consistent binding
2914 if binding_i.binding_mode != binding_j.binding_mode {
2917 .or_insert((binding_j.span, binding_i.span));
2925 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2926 missing_vars.sort();
2927 for (_, v) in missing_vars {
2929 *v.origin.iter().next().unwrap(),
2930 ResolutionError::VariableNotBoundInPattern(v));
2932 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2933 inconsistent_vars.sort();
2934 for (name, v) in inconsistent_vars {
2935 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2939 fn resolve_arm(&mut self, arm: &Arm) {
2940 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2942 let mut bindings_list = FxHashMap::default();
2943 for pattern in &arm.pats {
2944 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2947 // This has to happen *after* we determine which pat_idents are variants.
2948 self.check_consistent_bindings(&arm.pats);
2950 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2951 self.visit_expr(expr)
2953 self.visit_expr(&arm.body);
2955 self.ribs[ValueNS].pop();
2958 fn resolve_block(&mut self, block: &Block) {
2959 debug!("(resolving block) entering block");
2960 // Move down in the graph, if there's an anonymous module rooted here.
2961 let orig_module = self.current_module;
2962 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2964 let mut num_macro_definition_ribs = 0;
2965 if let Some(anonymous_module) = anonymous_module {
2966 debug!("(resolving block) found anonymous module, moving down");
2967 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2968 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2969 self.current_module = anonymous_module;
2970 self.finalize_current_module_macro_resolutions();
2972 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2975 // Descend into the block.
2976 for stmt in &block.stmts {
2977 if let ast::StmtKind::Item(ref item) = stmt.node {
2978 if let ast::ItemKind::MacroDef(..) = item.node {
2979 num_macro_definition_ribs += 1;
2980 let def = self.definitions.local_def_id(item.id);
2981 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2982 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2986 self.visit_stmt(stmt);
2990 self.current_module = orig_module;
2991 for _ in 0 .. num_macro_definition_ribs {
2992 self.ribs[ValueNS].pop();
2993 self.label_ribs.pop();
2995 self.ribs[ValueNS].pop();
2996 if anonymous_module.is_some() {
2997 self.ribs[TypeNS].pop();
2999 debug!("(resolving block) leaving block");
3002 fn fresh_binding(&mut self,
3005 outer_pat_id: NodeId,
3006 pat_src: PatternSource,
3007 bindings: &mut FxHashMap<Ident, NodeId>)
3009 // Add the binding to the local ribs, if it
3010 // doesn't already exist in the bindings map. (We
3011 // must not add it if it's in the bindings map
3012 // because that breaks the assumptions later
3013 // passes make about or-patterns.)
3014 let ident = ident.modern_and_legacy();
3015 let mut def = Def::Local(pat_id);
3016 match bindings.get(&ident).cloned() {
3017 Some(id) if id == outer_pat_id => {
3018 // `Variant(a, a)`, error
3022 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3026 Some(..) if pat_src == PatternSource::FnParam => {
3027 // `fn f(a: u8, a: u8)`, error
3031 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3035 Some(..) if pat_src == PatternSource::Match ||
3036 pat_src == PatternSource::IfLet ||
3037 pat_src == PatternSource::WhileLet => {
3038 // `Variant1(a) | Variant2(a)`, ok
3039 // Reuse definition from the first `a`.
3040 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3043 span_bug!(ident.span, "two bindings with the same name from \
3044 unexpected pattern source {:?}", pat_src);
3047 // A completely fresh binding, add to the lists if it's valid.
3048 if ident.name != keywords::Invalid.name() {
3049 bindings.insert(ident, outer_pat_id);
3050 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3055 PathResolution::new(def)
3058 fn resolve_pattern(&mut self,
3060 pat_src: PatternSource,
3061 // Maps idents to the node ID for the
3062 // outermost pattern that binds them.
3063 bindings: &mut FxHashMap<Ident, NodeId>) {
3064 // Visit all direct subpatterns of this pattern.
3065 let outer_pat_id = pat.id;
3066 pat.walk(&mut |pat| {
3067 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3069 PatKind::Ident(bmode, ident, ref opt_pat) => {
3070 // First try to resolve the identifier as some existing
3071 // entity, then fall back to a fresh binding.
3072 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3074 .and_then(LexicalScopeBinding::item);
3075 let resolution = binding.map(NameBinding::def).and_then(|def| {
3076 let is_syntactic_ambiguity = opt_pat.is_none() &&
3077 bmode == BindingMode::ByValue(Mutability::Immutable);
3079 Def::StructCtor(_, CtorKind::Const) |
3080 Def::VariantCtor(_, CtorKind::Const) |
3081 Def::Const(..) if is_syntactic_ambiguity => {
3082 // Disambiguate in favor of a unit struct/variant
3083 // or constant pattern.
3084 self.record_use(ident, ValueNS, binding.unwrap(), false);
3085 Some(PathResolution::new(def))
3087 Def::StructCtor(..) | Def::VariantCtor(..) |
3088 Def::Const(..) | Def::Static(..) => {
3089 // This is unambiguously a fresh binding, either syntactically
3090 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3091 // to something unusable as a pattern (e.g., constructor function),
3092 // but we still conservatively report an error, see
3093 // issues/33118#issuecomment-233962221 for one reason why.
3097 ResolutionError::BindingShadowsSomethingUnacceptable(
3098 pat_src.descr(), ident.name, binding.unwrap())
3102 Def::Fn(..) | Def::Err => {
3103 // These entities are explicitly allowed
3104 // to be shadowed by fresh bindings.
3108 span_bug!(ident.span, "unexpected definition for an \
3109 identifier in pattern: {:?}", def);
3112 }).unwrap_or_else(|| {
3113 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3116 self.record_def(pat.id, resolution);
3119 PatKind::TupleStruct(ref path, ..) => {
3120 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3123 PatKind::Path(ref qself, ref path) => {
3124 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3127 PatKind::Struct(ref path, ..) => {
3128 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3136 visit::walk_pat(self, pat);
3139 // High-level and context dependent path resolution routine.
3140 // Resolves the path and records the resolution into definition map.
3141 // If resolution fails tries several techniques to find likely
3142 // resolution candidates, suggest imports or other help, and report
3143 // errors in user friendly way.
3144 fn smart_resolve_path(&mut self,
3146 qself: Option<&QSelf>,
3148 source: PathSource<'_>)
3150 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3153 /// A variant of `smart_resolve_path` where you also specify extra
3154 /// information about where the path came from; this extra info is
3155 /// sometimes needed for the lint that recommends rewriting
3156 /// absolute paths to `crate`, so that it knows how to frame the
3157 /// suggestion. If you are just resolving a path like `foo::bar`
3158 /// that appears...somewhere, though, then you just want
3159 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3160 /// already provides.
3161 fn smart_resolve_path_with_crate_lint(
3164 qself: Option<&QSelf>,
3166 source: PathSource<'_>,
3167 crate_lint: CrateLint
3168 ) -> PathResolution {
3169 self.smart_resolve_path_fragment(
3172 &Segment::from_path(path),
3179 fn smart_resolve_path_fragment(&mut self,
3181 qself: Option<&QSelf>,
3184 source: PathSource<'_>,
3185 crate_lint: CrateLint)
3187 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3188 let ns = source.namespace();
3189 let is_expected = &|def| source.is_expected(def);
3190 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3192 // Base error is amended with one short label and possibly some longer helps/notes.
3193 let report_errors = |this: &mut Self, def: Option<Def>| {
3194 // Make the base error.
3195 let expected = source.descr_expected();
3196 let path_str = Segment::names_to_string(path);
3197 let item_str = path.last().unwrap().ident;
3198 let code = source.error_code(def.is_some());
3199 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3200 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3201 format!("not a {}", expected),
3204 let item_span = path.last().unwrap().ident.span;
3205 let (mod_prefix, mod_str) = if path.len() == 1 {
3206 (String::new(), "this scope".to_string())
3207 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3208 (String::new(), "the crate root".to_string())
3210 let mod_path = &path[..path.len() - 1];
3211 let mod_prefix = match this.resolve_path_without_parent_scope(
3212 mod_path, Some(TypeNS), false, span, CrateLint::No
3214 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3217 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3218 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3220 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3221 format!("not found in {}", mod_str),
3225 let code = DiagnosticId::Error(code.into());
3226 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3228 // Emit help message for fake-self from other languages like `this`(javascript)
3229 if ["this", "my"].contains(&&*item_str.as_str())
3230 && this.self_value_is_available(path[0].ident.span, span) {
3231 err.span_suggestion(
3235 Applicability::MaybeIncorrect,
3239 // Emit special messages for unresolved `Self` and `self`.
3240 if is_self_type(path, ns) {
3241 __diagnostic_used!(E0411);
3242 err.code(DiagnosticId::Error("E0411".into()));
3243 err.span_label(span, format!("`Self` is only available in impls, traits, \
3244 and type definitions"));
3245 return (err, Vec::new());
3247 if is_self_value(path, ns) {
3248 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3250 __diagnostic_used!(E0424);
3251 err.code(DiagnosticId::Error("E0424".into()));
3252 err.span_label(span, match source {
3253 PathSource::Pat => {
3254 format!("`self` value is a keyword \
3255 and may not be bound to \
3256 variables or shadowed")
3259 format!("`self` value is a keyword \
3260 only available in methods \
3261 with `self` parameter")
3264 return (err, Vec::new());
3267 // Try to lookup the name in more relaxed fashion for better error reporting.
3268 let ident = path.last().unwrap().ident;
3269 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3270 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3271 let enum_candidates =
3272 this.lookup_import_candidates(ident, ns, is_enum_variant);
3273 let mut enum_candidates = enum_candidates.iter()
3275 import_candidate_to_enum_paths(&suggestion)
3276 }).collect::<Vec<_>>();
3277 enum_candidates.sort();
3279 if !enum_candidates.is_empty() {
3280 // contextualize for E0412 "cannot find type", but don't belabor the point
3281 // (that it's a variant) for E0573 "expected type, found variant"
3282 let preamble = if def.is_none() {
3283 let others = match enum_candidates.len() {
3285 2 => " and 1 other".to_owned(),
3286 n => format!(" and {} others", n)
3288 format!("there is an enum variant `{}`{}; ",
3289 enum_candidates[0].0, others)
3293 let msg = format!("{}try using the variant's enum", preamble);
3295 err.span_suggestions(
3298 enum_candidates.into_iter()
3299 .map(|(_variant_path, enum_ty_path)| enum_ty_path)
3300 // variants reëxported in prelude doesn't mean `prelude::v1` is the
3301 // type name! FIXME: is there a more principled way to do this that
3302 // would work for other reëxports?
3303 .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
3304 // also say `Option` rather than `std::prelude::v1::Option`
3305 .map(|enum_ty_path| {
3306 // FIXME #56861: DRYer prelude filtering
3307 enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
3309 Applicability::MachineApplicable,
3313 if path.len() == 1 && this.self_type_is_available(span) {
3314 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3315 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3317 AssocSuggestion::Field => {
3318 err.span_suggestion(
3321 format!("self.{}", path_str),
3322 Applicability::MachineApplicable,
3324 if !self_is_available {
3325 err.span_label(span, format!("`self` value is a keyword \
3327 methods with `self` parameter"));
3330 AssocSuggestion::MethodWithSelf if self_is_available => {
3331 err.span_suggestion(
3334 format!("self.{}", path_str),
3335 Applicability::MachineApplicable,
3338 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3339 err.span_suggestion(
3342 format!("Self::{}", path_str),
3343 Applicability::MachineApplicable,
3347 return (err, candidates);
3351 let mut levenshtein_worked = false;
3353 // Try Levenshtein algorithm.
3354 let suggestion = this.lookup_typo_candidate(path, ns, is_expected, span);
3355 if let Some(suggestion) = suggestion {
3357 "{} {} with a similar name exists",
3358 suggestion.article, suggestion.kind
3360 err.span_suggestion(
3363 suggestion.candidate.to_string(),
3364 Applicability::MaybeIncorrect,
3367 levenshtein_worked = true;
3370 // Try context dependent help if relaxed lookup didn't work.
3371 if let Some(def) = def {
3372 match (def, source) {
3373 (Def::Macro(..), _) => {
3374 err.span_suggestion(
3376 "use `!` to invoke the macro",
3377 format!("{}!", path_str),
3378 Applicability::MaybeIncorrect,
3380 return (err, candidates);
3382 (Def::TyAlias(..), PathSource::Trait(_)) => {
3383 err.span_label(span, "type aliases cannot be used as traits");
3384 if nightly_options::is_nightly_build() {
3385 err.note("did you mean to use a trait alias?");
3387 return (err, candidates);
3389 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3390 ExprKind::Field(_, ident) => {
3391 err.span_suggestion(
3393 "use the path separator to refer to an item",
3394 format!("{}::{}", path_str, ident),
3395 Applicability::MaybeIncorrect,
3397 return (err, candidates);
3399 ExprKind::MethodCall(ref segment, ..) => {
3400 let span = parent.span.with_hi(segment.ident.span.hi());
3401 err.span_suggestion(
3403 "use the path separator to refer to an item",
3404 format!("{}::{}", path_str, segment.ident),
3405 Applicability::MaybeIncorrect,
3407 return (err, candidates);
3411 (Def::Enum(..), PathSource::TupleStruct)
3412 | (Def::Enum(..), PathSource::Expr(..)) => {
3413 if let Some(variants) = this.collect_enum_variants(def) {
3414 err.note(&format!("did you mean to use one \
3415 of the following variants?\n{}",
3417 .map(|suggestion| path_names_to_string(suggestion))
3418 .map(|suggestion| format!("- `{}`", suggestion))
3419 .collect::<Vec<_>>()
3423 err.note("did you mean to use one of the enum's variants?");
3425 return (err, candidates);
3427 (Def::Struct(def_id), _) if ns == ValueNS => {
3428 if let Some((ctor_def, ctor_vis))
3429 = this.struct_constructors.get(&def_id).cloned() {
3430 let accessible_ctor = this.is_accessible(ctor_vis);
3431 if is_expected(ctor_def) && !accessible_ctor {
3432 err.span_label(span, format!("constructor is not visible \
3433 here due to private fields"));
3436 // HACK(estebank): find a better way to figure out that this was a
3437 // parser issue where a struct literal is being used on an expression
3438 // where a brace being opened means a block is being started. Look
3439 // ahead for the next text to see if `span` is followed by a `{`.
3440 let sm = this.session.source_map();
3443 sp = sm.next_point(sp);
3444 match sm.span_to_snippet(sp) {
3445 Ok(ref snippet) => {
3446 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3453 let followed_by_brace = match sm.span_to_snippet(sp) {
3454 Ok(ref snippet) if snippet == "{" => true,
3457 // In case this could be a struct literal that needs to be surrounded
3458 // by parenthesis, find the appropriate span.
3460 let mut closing_brace = None;
3462 sp = sm.next_point(sp);
3463 match sm.span_to_snippet(sp) {
3464 Ok(ref snippet) => {
3466 let sp = span.to(sp);
3467 if let Ok(snippet) = sm.span_to_snippet(sp) {
3468 closing_brace = Some((sp, snippet));
3476 if i > 100 { // The bigger the span the more likely we're
3477 break; // incorrect. Bound it to 100 chars long.
3481 PathSource::Expr(Some(parent)) => {
3483 ExprKind::MethodCall(ref path_assignment, _) => {
3484 err.span_suggestion(
3485 sm.start_point(parent.span)
3486 .to(path_assignment.ident.span),
3487 "use `::` to access an associated function",
3490 path_assignment.ident),
3491 Applicability::MaybeIncorrect
3493 return (err, candidates);
3498 format!("did you mean `{} {{ /* fields */ }}`?",
3501 return (err, candidates);
3505 PathSource::Expr(None) if followed_by_brace == true => {
3506 if let Some((sp, snippet)) = closing_brace {
3507 err.span_suggestion(
3509 "surround the struct literal with parenthesis",
3510 format!("({})", snippet),
3511 Applicability::MaybeIncorrect,
3516 format!("did you mean `({} {{ /* fields */ }})`?",
3520 return (err, candidates);
3525 format!("did you mean `{} {{ /* fields */ }}`?",
3528 return (err, candidates);
3532 return (err, candidates);
3534 (Def::Union(..), _) |
3535 (Def::Variant(..), _) |
3536 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3537 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3539 return (err, candidates);
3541 (Def::SelfTy(..), _) if ns == ValueNS => {
3542 err.span_label(span, fallback_label);
3543 err.note("can't use `Self` as a constructor, you must use the \
3544 implemented struct");
3545 return (err, candidates);
3547 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3548 err.note("can't use a type alias as a constructor");
3549 return (err, candidates);
3556 if !levenshtein_worked {
3557 err.span_label(base_span, fallback_label);
3558 this.type_ascription_suggestion(&mut err, base_span);
3562 let report_errors = |this: &mut Self, def: Option<Def>| {
3563 let (err, candidates) = report_errors(this, def);
3564 let def_id = this.current_module.normal_ancestor_id;
3565 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3566 let better = def.is_some();
3567 this.use_injections.push(UseError { err, candidates, node_id, better });
3568 err_path_resolution()
3571 let resolution = match self.resolve_qpath_anywhere(
3577 source.defer_to_typeck(),
3578 source.global_by_default(),
3581 Some(resolution) if resolution.unresolved_segments() == 0 => {
3582 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3585 // Add a temporary hack to smooth the transition to new struct ctor
3586 // visibility rules. See #38932 for more details.
3588 if let Def::Struct(def_id) = resolution.base_def() {
3589 if let Some((ctor_def, ctor_vis))
3590 = self.struct_constructors.get(&def_id).cloned() {
3591 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3592 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3593 self.session.buffer_lint(lint, id, span,
3594 "private struct constructors are not usable through \
3595 re-exports in outer modules",
3597 res = Some(PathResolution::new(ctor_def));
3602 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3605 Some(resolution) if source.defer_to_typeck() => {
3606 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3607 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3608 // it needs to be added to the trait map.
3610 let item_name = path.last().unwrap().ident;
3611 let traits = self.get_traits_containing_item(item_name, ns);
3612 self.trait_map.insert(id, traits);
3616 _ => report_errors(self, None)
3619 if let PathSource::TraitItem(..) = source {} else {
3620 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3621 self.record_def(id, resolution);
3626 fn type_ascription_suggestion(&self,
3627 err: &mut DiagnosticBuilder<'_>,
3629 debug!("type_ascription_suggetion {:?}", base_span);
3630 let cm = self.session.source_map();
3631 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3632 if let Some(sp) = self.current_type_ascription.last() {
3634 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3635 sp = cm.next_point(sp);
3636 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3637 debug!("snippet {:?}", snippet);
3638 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3639 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3640 debug!("{:?} {:?}", line_sp, line_base_sp);
3642 err.span_label(base_span,
3643 "expecting a type here because of type ascription");
3644 if line_sp != line_base_sp {
3645 err.span_suggestion_short(
3647 "did you mean to use `;` here instead?",
3649 Applicability::MaybeIncorrect,
3653 } else if !snippet.trim().is_empty() {
3654 debug!("tried to find type ascription `:` token, couldn't find it");
3664 fn self_type_is_available(&mut self, span: Span) -> bool {
3665 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3666 TypeNS, None, span);
3667 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3670 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3671 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3672 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3673 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3676 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3677 fn resolve_qpath_anywhere(&mut self,
3679 qself: Option<&QSelf>,
3681 primary_ns: Namespace,
3683 defer_to_typeck: bool,
3684 global_by_default: bool,
3685 crate_lint: CrateLint)
3686 -> Option<PathResolution> {
3687 let mut fin_res = None;
3688 // FIXME: can't resolve paths in macro namespace yet, macros are
3689 // processed by the little special hack below.
3690 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3691 if i == 0 || ns != primary_ns {
3692 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3693 // If defer_to_typeck, then resolution > no resolution,
3694 // otherwise full resolution > partial resolution > no resolution.
3695 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3697 res => if fin_res.is_none() { fin_res = res },
3701 if primary_ns != MacroNS &&
3702 (self.macro_names.contains(&path[0].ident.modern()) ||
3703 self.builtin_macros.get(&path[0].ident.name).cloned()
3704 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3705 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3706 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3707 // Return some dummy definition, it's enough for error reporting.
3709 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3715 /// Handles paths that may refer to associated items.
3716 fn resolve_qpath(&mut self,
3718 qself: Option<&QSelf>,
3722 global_by_default: bool,
3723 crate_lint: CrateLint)
3724 -> Option<PathResolution> {
3726 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3727 ns={:?}, span={:?}, global_by_default={:?})",
3736 if let Some(qself) = qself {
3737 if qself.position == 0 {
3738 // This is a case like `<T>::B`, where there is no
3739 // trait to resolve. In that case, we leave the `B`
3740 // segment to be resolved by type-check.
3741 return Some(PathResolution::with_unresolved_segments(
3742 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3746 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3748 // Currently, `path` names the full item (`A::B::C`, in
3749 // our example). so we extract the prefix of that that is
3750 // the trait (the slice upto and including
3751 // `qself.position`). And then we recursively resolve that,
3752 // but with `qself` set to `None`.
3754 // However, setting `qself` to none (but not changing the
3755 // span) loses the information about where this path
3756 // *actually* appears, so for the purposes of the crate
3757 // lint we pass along information that this is the trait
3758 // name from a fully qualified path, and this also
3759 // contains the full span (the `CrateLint::QPathTrait`).
3760 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3761 let res = self.smart_resolve_path_fragment(
3764 &path[..=qself.position],
3766 PathSource::TraitItem(ns),
3767 CrateLint::QPathTrait {
3769 qpath_span: qself.path_span,
3773 // The remaining segments (the `C` in our example) will
3774 // have to be resolved by type-check, since that requires doing
3775 // trait resolution.
3776 return Some(PathResolution::with_unresolved_segments(
3777 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3781 let result = match self.resolve_path_without_parent_scope(
3788 PathResult::NonModule(path_res) => path_res,
3789 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3790 PathResolution::new(module.def().unwrap())
3792 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3793 // don't report an error right away, but try to fallback to a primitive type.
3794 // So, we are still able to successfully resolve something like
3796 // use std::u8; // bring module u8 in scope
3797 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3798 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3799 // // not to non-existent std::u8::max_value
3802 // Such behavior is required for backward compatibility.
3803 // The same fallback is used when `a` resolves to nothing.
3804 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3805 PathResult::Failed(..)
3806 if (ns == TypeNS || path.len() > 1) &&
3807 self.primitive_type_table.primitive_types
3808 .contains_key(&path[0].ident.name) => {
3809 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3810 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3812 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3813 PathResolution::new(module.def().unwrap()),
3814 PathResult::Failed(span, msg, false) => {
3815 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3816 err_path_resolution()
3818 PathResult::Module(..) | PathResult::Failed(..) => return None,
3819 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3822 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3823 path[0].ident.name != keywords::PathRoot.name() &&
3824 path[0].ident.name != keywords::DollarCrate.name() {
3825 let unqualified_result = {
3826 match self.resolve_path_without_parent_scope(
3827 &[*path.last().unwrap()],
3833 PathResult::NonModule(path_res) => path_res.base_def(),
3834 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3835 module.def().unwrap(),
3836 _ => return Some(result),
3839 if result.base_def() == unqualified_result {
3840 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3841 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3848 fn resolve_path_without_parent_scope(
3851 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3854 crate_lint: CrateLint,
3855 ) -> PathResult<'a> {
3856 // Macro and import paths must have full parent scope available during resolution,
3857 // other paths will do okay with parent module alone.
3858 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3859 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3860 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3866 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3867 parent_scope: &ParentScope<'a>,
3870 crate_lint: CrateLint,
3871 ) -> PathResult<'a> {
3872 let mut module = None;
3873 let mut allow_super = true;
3874 let mut second_binding = None;
3875 self.current_module = parent_scope.module;
3878 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3879 path_span={:?}, crate_lint={:?})",
3887 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3888 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3889 let record_segment_def = |this: &mut Self, def| {
3891 if let Some(id) = id {
3892 if !this.def_map.contains_key(&id) {
3893 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3894 this.record_def(id, PathResolution::new(def));
3900 let is_last = i == path.len() - 1;
3901 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3902 let name = ident.name;
3904 allow_super &= ns == TypeNS &&
3905 (name == keywords::SelfLower.name() ||
3906 name == keywords::Super.name());
3909 if allow_super && name == keywords::Super.name() {
3910 let mut ctxt = ident.span.ctxt().modern();
3911 let self_module = match i {
3912 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3914 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3918 if let Some(self_module) = self_module {
3919 if let Some(parent) = self_module.parent {
3920 module = Some(ModuleOrUniformRoot::Module(
3921 self.resolve_self(&mut ctxt, parent)));
3925 let msg = "there are too many initial `super`s.".to_string();
3926 return PathResult::Failed(ident.span, msg, false);
3929 if name == keywords::SelfLower.name() {
3930 let mut ctxt = ident.span.ctxt().modern();
3931 module = Some(ModuleOrUniformRoot::Module(
3932 self.resolve_self(&mut ctxt, self.current_module)));
3935 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3936 module = Some(ModuleOrUniformRoot::ExternPrelude);
3939 if name == keywords::PathRoot.name() &&
3940 ident.span.rust_2015() && self.session.rust_2018() {
3941 // `::a::b` from 2015 macro on 2018 global edition
3942 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3945 if name == keywords::PathRoot.name() ||
3946 name == keywords::Crate.name() ||
3947 name == keywords::DollarCrate.name() {
3948 // `::a::b`, `crate::a::b` or `$crate::a::b`
3949 module = Some(ModuleOrUniformRoot::Module(
3950 self.resolve_crate_root(ident)));
3956 // Report special messages for path segment keywords in wrong positions.
3957 if ident.is_path_segment_keyword() && i != 0 {
3958 let name_str = if name == keywords::PathRoot.name() {
3959 "crate root".to_string()
3961 format!("`{}`", name)
3963 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3964 format!("global paths cannot start with {}", name_str)
3966 format!("{} in paths can only be used in start position", name_str)
3968 return PathResult::Failed(ident.span, msg, false);
3971 let binding = if let Some(module) = module {
3972 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3973 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3974 assert!(ns == TypeNS);
3975 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3976 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3977 record_used, path_span)
3979 let record_used_id =
3980 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3981 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3982 // we found a locally-imported or available item/module
3983 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3984 // we found a local variable or type param
3985 Some(LexicalScopeBinding::Def(def))
3986 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3987 record_segment_def(self, def);
3988 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3992 _ => Err(Determinacy::determined(record_used)),
3999 second_binding = Some(binding);
4001 let def = binding.def();
4002 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
4003 if let Some(next_module) = binding.module() {
4004 module = Some(ModuleOrUniformRoot::Module(next_module));
4005 record_segment_def(self, def);
4006 } else if def == Def::ToolMod && i + 1 != path.len() {
4007 if binding.is_import() {
4008 self.session.struct_span_err(
4009 ident.span, "cannot use a tool module through an import"
4011 binding.span, "the tool module imported here"
4014 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
4015 return PathResult::NonModule(PathResolution::new(def));
4016 } else if def == Def::Err {
4017 return PathResult::NonModule(err_path_resolution());
4018 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
4019 self.lint_if_path_starts_with_module(
4025 return PathResult::NonModule(PathResolution::with_unresolved_segments(
4026 def, path.len() - i - 1
4029 return PathResult::Failed(ident.span,
4030 format!("not a module `{}`", ident),
4034 Err(Undetermined) => return PathResult::Indeterminate,
4035 Err(Determined) => {
4036 if let Some(ModuleOrUniformRoot::Module(module)) = module {
4037 if opt_ns.is_some() && !module.is_normal() {
4038 return PathResult::NonModule(PathResolution::with_unresolved_segments(
4039 module.def().unwrap(), path.len() - i
4043 let module_def = match module {
4044 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
4047 let msg = if module_def == self.graph_root.def() {
4048 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
4049 let mut candidates =
4050 self.lookup_import_candidates(ident, TypeNS, is_mod);
4051 candidates.sort_by_cached_key(|c| {
4052 (c.path.segments.len(), c.path.to_string())
4054 if let Some(candidate) = candidates.get(0) {
4055 format!("did you mean `{}`?", candidate.path)
4056 } else if !ident.is_reserved() {
4057 format!("maybe a missing `extern crate {};`?", ident)
4059 // the parser will already have complained about the keyword being used
4060 return PathResult::NonModule(err_path_resolution());
4063 format!("use of undeclared type or module `{}`", ident)
4065 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
4067 return PathResult::Failed(ident.span, msg, is_last);
4072 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
4074 PathResult::Module(match module {
4075 Some(module) => module,
4076 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
4077 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
4081 fn lint_if_path_starts_with_module(
4083 crate_lint: CrateLint,
4086 second_binding: Option<&NameBinding<'_>>,
4088 let (diag_id, diag_span) = match crate_lint {
4089 CrateLint::No => return,
4090 CrateLint::SimplePath(id) => (id, path_span),
4091 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
4092 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
4095 let first_name = match path.get(0) {
4096 // In the 2018 edition this lint is a hard error, so nothing to do
4097 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
4101 // We're only interested in `use` paths which should start with
4102 // `{{root}}` currently.
4103 if first_name != keywords::PathRoot.name() {
4108 // If this import looks like `crate::...` it's already good
4109 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
4110 // Otherwise go below to see if it's an extern crate
4112 // If the path has length one (and it's `PathRoot` most likely)
4113 // then we don't know whether we're gonna be importing a crate or an
4114 // item in our crate. Defer this lint to elsewhere
4118 // If the first element of our path was actually resolved to an
4119 // `ExternCrate` (also used for `crate::...`) then no need to issue a
4120 // warning, this looks all good!
4121 if let Some(binding) = second_binding {
4122 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
4123 // Careful: we still want to rewrite paths from
4124 // renamed extern crates.
4125 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
4131 let diag = lint::builtin::BuiltinLintDiagnostics
4132 ::AbsPathWithModule(diag_span);
4133 self.session.buffer_lint_with_diagnostic(
4134 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
4136 "absolute paths must start with `self`, `super`, \
4137 `crate`, or an external crate name in the 2018 edition",
4141 // Resolve a local definition, potentially adjusting for closures.
4142 fn adjust_local_def(&mut self,
4147 span: Span) -> Def {
4148 debug!("adjust_local_def");
4149 let ribs = &self.ribs[ns][rib_index + 1..];
4151 // An invalid forward use of a type parameter from a previous default.
4152 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4154 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4156 assert_eq!(def, Def::Err);
4162 span_bug!(span, "unexpected {:?} in bindings", def)
4164 Def::Local(node_id) => {
4165 use ResolutionError::*;
4166 let mut res_err = None;
4170 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4171 ForwardTyParamBanRibKind => {
4172 // Nothing to do. Continue.
4174 ClosureRibKind(function_id) => {
4177 let seen = self.freevars_seen
4180 if let Some(&index) = seen.get(&node_id) {
4181 def = Def::Upvar(node_id, index, function_id);
4184 let vec = self.freevars
4187 let depth = vec.len();
4188 def = Def::Upvar(node_id, depth, function_id);
4195 seen.insert(node_id, depth);
4198 ItemRibKind | TraitOrImplItemRibKind => {
4199 // This was an attempt to access an upvar inside a
4200 // named function item. This is not allowed, so we
4203 // We don't immediately trigger a resolve error, because
4204 // we want certain other resolution errors (namely those
4205 // emitted for `ConstantItemRibKind` below) to take
4207 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
4210 ConstantItemRibKind => {
4211 // Still doesn't deal with upvars
4213 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
4219 if let Some(res_err) = res_err {
4220 resolve_error(self, span, res_err);
4224 Def::TyParam(..) | Def::SelfTy(..) => {
4227 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4228 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4229 ConstantItemRibKind => {
4230 // Nothing to do. Continue.
4233 // This was an attempt to use a type parameter outside its scope.
4238 ResolutionError::GenericParamsFromOuterFunction(def),
4246 Def::ConstParam(..) => {
4247 // A const param is always declared in a signature, which is always followed by
4248 // some kind of function rib kind (specifically, ItemRibKind in the case of a
4249 // normal function), so we can skip the first rib as it will be guaranteed to
4250 // (spuriously) conflict with the const param.
4251 for rib in &ribs[1..] {
4252 if let ItemRibKind = rib.kind {
4253 // This was an attempt to use a const parameter outside its scope.
4258 ResolutionError::GenericParamsFromOuterFunction(def),
4270 fn lookup_assoc_candidate<FilterFn>(&mut self,
4273 filter_fn: FilterFn)
4274 -> Option<AssocSuggestion>
4275 where FilterFn: Fn(Def) -> bool
4277 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4279 TyKind::Path(None, _) => Some(t.id),
4280 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4281 // This doesn't handle the remaining `Ty` variants as they are not
4282 // that commonly the self_type, it might be interesting to provide
4283 // support for those in future.
4288 // Fields are generally expected in the same contexts as locals.
4289 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4290 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4291 // Look for a field with the same name in the current self_type.
4292 if let Some(resolution) = self.def_map.get(&node_id) {
4293 match resolution.base_def() {
4294 Def::Struct(did) | Def::Union(did)
4295 if resolution.unresolved_segments() == 0 => {
4296 if let Some(field_names) = self.field_names.get(&did) {
4297 if field_names.iter().any(|&field_name| ident.name == field_name) {
4298 return Some(AssocSuggestion::Field);
4308 // Look for associated items in the current trait.
4309 if let Some((module, _)) = self.current_trait_ref {
4310 if let Ok(binding) = self.resolve_ident_in_module(
4311 ModuleOrUniformRoot::Module(module),
4318 let def = binding.def();
4320 return Some(if self.has_self.contains(&def.def_id()) {
4321 AssocSuggestion::MethodWithSelf
4323 AssocSuggestion::AssocItem
4332 fn lookup_typo_candidate<FilterFn>(
4336 filter_fn: FilterFn,
4338 ) -> Option<TypoSuggestion>
4340 FilterFn: Fn(Def) -> bool,
4342 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4343 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4344 if let Some(binding) = resolution.borrow().binding {
4345 if filter_fn(binding.def()) {
4346 names.push(TypoSuggestion {
4347 candidate: ident.name,
4348 article: binding.def().article(),
4349 kind: binding.def().kind_name(),
4356 let mut names = Vec::new();
4357 if path.len() == 1 {
4358 // Search in lexical scope.
4359 // Walk backwards up the ribs in scope and collect candidates.
4360 for rib in self.ribs[ns].iter().rev() {
4361 // Locals and type parameters
4362 for (ident, def) in &rib.bindings {
4363 if filter_fn(*def) {
4364 names.push(TypoSuggestion {
4365 candidate: ident.name,
4366 article: def.article(),
4367 kind: def.kind_name(),
4372 if let ModuleRibKind(module) = rib.kind {
4373 // Items from this module
4374 add_module_candidates(module, &mut names);
4376 if let ModuleKind::Block(..) = module.kind {
4377 // We can see through blocks
4379 // Items from the prelude
4380 if !module.no_implicit_prelude {
4381 names.extend(self.extern_prelude.iter().map(|(ident, _)| {
4383 candidate: ident.name,
4388 if let Some(prelude) = self.prelude {
4389 add_module_candidates(prelude, &mut names);
4396 // Add primitive types to the mix
4397 if filter_fn(Def::PrimTy(Bool)) {
4399 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4403 kind: "primitive type",
4409 // Search in module.
4410 let mod_path = &path[..path.len() - 1];
4411 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4412 mod_path, Some(TypeNS), false, span, CrateLint::No
4414 if let ModuleOrUniformRoot::Module(module) = module {
4415 add_module_candidates(module, &mut names);
4420 let name = path[path.len() - 1].ident.name;
4421 // Make sure error reporting is deterministic.
4422 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4424 match find_best_match_for_name(
4425 names.iter().map(|suggestion| &suggestion.candidate),
4429 Some(found) if found != name => names
4431 .find(|suggestion| suggestion.candidate == found),
4436 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4437 where F: FnOnce(&mut Resolver<'_>)
4439 if let Some(label) = label {
4440 self.unused_labels.insert(id, label.ident.span);
4441 let def = Def::Label(id);
4442 self.with_label_rib(|this| {
4443 let ident = label.ident.modern_and_legacy();
4444 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4452 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4453 self.with_resolved_label(label, id, |this| this.visit_block(block));
4456 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4457 // First, record candidate traits for this expression if it could
4458 // result in the invocation of a method call.
4460 self.record_candidate_traits_for_expr_if_necessary(expr);
4462 // Next, resolve the node.
4464 ExprKind::Path(ref qself, ref path) => {
4465 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4466 visit::walk_expr(self, expr);
4469 ExprKind::Struct(ref path, ..) => {
4470 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4471 visit::walk_expr(self, expr);
4474 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4475 let def = self.search_label(label.ident, |rib, ident| {
4476 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4480 // Search again for close matches...
4481 // Picks the first label that is "close enough", which is not necessarily
4482 // the closest match
4483 let close_match = self.search_label(label.ident, |rib, ident| {
4484 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4485 find_best_match_for_name(names, &*ident.as_str(), None)
4487 self.record_def(expr.id, err_path_resolution());
4490 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4493 Some(Def::Label(id)) => {
4494 // Since this def is a label, it is never read.
4495 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4496 self.unused_labels.remove(&id);
4499 span_bug!(expr.span, "label wasn't mapped to a label def!");
4503 // visit `break` argument if any
4504 visit::walk_expr(self, expr);
4507 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4508 self.visit_expr(subexpression);
4510 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4511 let mut bindings_list = FxHashMap::default();
4513 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4515 // This has to happen *after* we determine which pat_idents are variants
4516 self.check_consistent_bindings(pats);
4517 self.visit_block(if_block);
4518 self.ribs[ValueNS].pop();
4520 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4523 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4525 ExprKind::While(ref subexpression, ref block, label) => {
4526 self.with_resolved_label(label, expr.id, |this| {
4527 this.visit_expr(subexpression);
4528 this.visit_block(block);
4532 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4533 self.with_resolved_label(label, expr.id, |this| {
4534 this.visit_expr(subexpression);
4535 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4536 let mut bindings_list = FxHashMap::default();
4538 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4540 // This has to happen *after* we determine which pat_idents are variants.
4541 this.check_consistent_bindings(pats);
4542 this.visit_block(block);
4543 this.ribs[ValueNS].pop();
4547 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4548 self.visit_expr(subexpression);
4549 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4550 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4552 self.resolve_labeled_block(label, expr.id, block);
4554 self.ribs[ValueNS].pop();
4557 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4559 // Equivalent to `visit::walk_expr` + passing some context to children.
4560 ExprKind::Field(ref subexpression, _) => {
4561 self.resolve_expr(subexpression, Some(expr));
4563 ExprKind::MethodCall(ref segment, ref arguments) => {
4564 let mut arguments = arguments.iter();
4565 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4566 for argument in arguments {
4567 self.resolve_expr(argument, None);
4569 self.visit_path_segment(expr.span, segment);
4572 ExprKind::Call(ref callee, ref arguments) => {
4573 self.resolve_expr(callee, Some(expr));
4574 for argument in arguments {
4575 self.resolve_expr(argument, None);
4578 ExprKind::Type(ref type_expr, _) => {
4579 self.current_type_ascription.push(type_expr.span);
4580 visit::walk_expr(self, expr);
4581 self.current_type_ascription.pop();
4583 // Resolve the body of async exprs inside the async closure to which they desugar
4584 ExprKind::Async(_, async_closure_id, ref block) => {
4585 let rib_kind = ClosureRibKind(async_closure_id);
4586 self.ribs[ValueNS].push(Rib::new(rib_kind));
4587 self.label_ribs.push(Rib::new(rib_kind));
4588 self.visit_block(&block);
4589 self.label_ribs.pop();
4590 self.ribs[ValueNS].pop();
4592 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4593 // resolve the arguments within the proper scopes so that usages of them inside the
4594 // closure are detected as upvars rather than normal closure arg usages.
4596 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4597 ref fn_decl, ref body, _span,
4599 let rib_kind = ClosureRibKind(expr.id);
4600 self.ribs[ValueNS].push(Rib::new(rib_kind));
4601 self.label_ribs.push(Rib::new(rib_kind));
4602 // Resolve arguments:
4603 let mut bindings_list = FxHashMap::default();
4604 for argument in &fn_decl.inputs {
4605 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4606 self.visit_ty(&argument.ty);
4608 // No need to resolve return type-- the outer closure return type is
4609 // FunctionRetTy::Default
4611 // Now resolve the inner closure
4613 let rib_kind = ClosureRibKind(inner_closure_id);
4614 self.ribs[ValueNS].push(Rib::new(rib_kind));
4615 self.label_ribs.push(Rib::new(rib_kind));
4616 // No need to resolve arguments: the inner closure has none.
4617 // Resolve the return type:
4618 visit::walk_fn_ret_ty(self, &fn_decl.output);
4620 self.visit_expr(body);
4621 self.label_ribs.pop();
4622 self.ribs[ValueNS].pop();
4624 self.label_ribs.pop();
4625 self.ribs[ValueNS].pop();
4628 visit::walk_expr(self, expr);
4633 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4635 ExprKind::Field(_, ident) => {
4636 // FIXME(#6890): Even though you can't treat a method like a
4637 // field, we need to add any trait methods we find that match
4638 // the field name so that we can do some nice error reporting
4639 // later on in typeck.
4640 let traits = self.get_traits_containing_item(ident, ValueNS);
4641 self.trait_map.insert(expr.id, traits);
4643 ExprKind::MethodCall(ref segment, ..) => {
4644 debug!("(recording candidate traits for expr) recording traits for {}",
4646 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4647 self.trait_map.insert(expr.id, traits);
4655 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4656 -> Vec<TraitCandidate> {
4657 debug!("(getting traits containing item) looking for '{}'", ident.name);
4659 let mut found_traits = Vec::new();
4660 // Look for the current trait.
4661 if let Some((module, _)) = self.current_trait_ref {
4662 if self.resolve_ident_in_module(
4663 ModuleOrUniformRoot::Module(module),
4670 let def_id = module.def_id().unwrap();
4671 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4675 ident.span = ident.span.modern();
4676 let mut search_module = self.current_module;
4678 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4679 search_module = unwrap_or!(
4680 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4684 if let Some(prelude) = self.prelude {
4685 if !search_module.no_implicit_prelude {
4686 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4693 fn get_traits_in_module_containing_item(&mut self,
4697 found_traits: &mut Vec<TraitCandidate>) {
4698 assert!(ns == TypeNS || ns == ValueNS);
4699 let mut traits = module.traits.borrow_mut();
4700 if traits.is_none() {
4701 let mut collected_traits = Vec::new();
4702 module.for_each_child(|name, ns, binding| {
4703 if ns != TypeNS { return }
4704 if let Def::Trait(_) = binding.def() {
4705 collected_traits.push((name, binding));
4708 *traits = Some(collected_traits.into_boxed_slice());
4711 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4712 let module = binding.module().unwrap();
4713 let mut ident = ident;
4714 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4717 if self.resolve_ident_in_module_unadjusted(
4718 ModuleOrUniformRoot::Module(module),
4724 let import_id = match binding.kind {
4725 NameBindingKind::Import { directive, .. } => {
4726 self.maybe_unused_trait_imports.insert(directive.id);
4727 self.add_to_glob_map(&directive, trait_name);
4732 let trait_def_id = module.def_id().unwrap();
4733 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4738 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4739 lookup_ident: Ident,
4740 namespace: Namespace,
4741 start_module: &'a ModuleData<'a>,
4743 filter_fn: FilterFn)
4744 -> Vec<ImportSuggestion>
4745 where FilterFn: Fn(Def) -> bool
4747 let mut candidates = Vec::new();
4748 let mut seen_modules = FxHashSet::default();
4749 let not_local_module = crate_name != keywords::Crate.ident();
4750 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4752 while let Some((in_module,
4754 in_module_is_extern)) = worklist.pop() {
4755 self.populate_module_if_necessary(in_module);
4757 // We have to visit module children in deterministic order to avoid
4758 // instabilities in reported imports (#43552).
4759 in_module.for_each_child_stable(|ident, ns, name_binding| {
4760 // avoid imports entirely
4761 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4762 // avoid non-importable candidates as well
4763 if !name_binding.is_importable() { return; }
4765 // collect results based on the filter function
4766 if ident.name == lookup_ident.name && ns == namespace {
4767 if filter_fn(name_binding.def()) {
4769 let mut segms = path_segments.clone();
4770 if lookup_ident.span.rust_2018() {
4771 // crate-local absolute paths start with `crate::` in edition 2018
4772 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4774 0, ast::PathSegment::from_ident(crate_name)
4778 segms.push(ast::PathSegment::from_ident(ident));
4780 span: name_binding.span,
4783 // the entity is accessible in the following cases:
4784 // 1. if it's defined in the same crate, it's always
4785 // accessible (since private entities can be made public)
4786 // 2. if it's defined in another crate, it's accessible
4787 // only if both the module is public and the entity is
4788 // declared as public (due to pruning, we don't explore
4789 // outside crate private modules => no need to check this)
4790 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4791 candidates.push(ImportSuggestion { path });
4796 // collect submodules to explore
4797 if let Some(module) = name_binding.module() {
4799 let mut path_segments = path_segments.clone();
4800 path_segments.push(ast::PathSegment::from_ident(ident));
4802 let is_extern_crate_that_also_appears_in_prelude =
4803 name_binding.is_extern_crate() &&
4804 lookup_ident.span.rust_2018();
4806 let is_visible_to_user =
4807 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4809 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4810 // add the module to the lookup
4811 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4812 if seen_modules.insert(module.def_id().unwrap()) {
4813 worklist.push((module, path_segments, is_extern));
4823 /// When name resolution fails, this method can be used to look up candidate
4824 /// entities with the expected name. It allows filtering them using the
4825 /// supplied predicate (which should be used to only accept the types of
4826 /// definitions expected e.g., traits). The lookup spans across all crates.
4828 /// NOTE: The method does not look into imports, but this is not a problem,
4829 /// since we report the definitions (thus, the de-aliased imports).
4830 fn lookup_import_candidates<FilterFn>(&mut self,
4831 lookup_ident: Ident,
4832 namespace: Namespace,
4833 filter_fn: FilterFn)
4834 -> Vec<ImportSuggestion>
4835 where FilterFn: Fn(Def) -> bool
4837 let mut suggestions = self.lookup_import_candidates_from_module(
4838 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4840 if lookup_ident.span.rust_2018() {
4841 let extern_prelude_names = self.extern_prelude.clone();
4842 for (ident, _) in extern_prelude_names.into_iter() {
4843 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4845 let crate_root = self.get_module(DefId {
4847 index: CRATE_DEF_INDEX,
4849 self.populate_module_if_necessary(&crate_root);
4851 suggestions.extend(self.lookup_import_candidates_from_module(
4852 lookup_ident, namespace, crate_root, ident, &filter_fn));
4860 fn find_module(&mut self,
4862 -> Option<(Module<'a>, ImportSuggestion)>
4864 let mut result = None;
4865 let mut seen_modules = FxHashSet::default();
4866 let mut worklist = vec![(self.graph_root, Vec::new())];
4868 while let Some((in_module, path_segments)) = worklist.pop() {
4869 // abort if the module is already found
4870 if result.is_some() { break; }
4872 self.populate_module_if_necessary(in_module);
4874 in_module.for_each_child_stable(|ident, _, name_binding| {
4875 // abort if the module is already found or if name_binding is private external
4876 if result.is_some() || !name_binding.vis.is_visible_locally() {
4879 if let Some(module) = name_binding.module() {
4881 let mut path_segments = path_segments.clone();
4882 path_segments.push(ast::PathSegment::from_ident(ident));
4883 if module.def() == Some(module_def) {
4885 span: name_binding.span,
4886 segments: path_segments,
4888 result = Some((module, ImportSuggestion { path }));
4890 // add the module to the lookup
4891 if seen_modules.insert(module.def_id().unwrap()) {
4892 worklist.push((module, path_segments));
4902 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4903 if let Def::Enum(..) = enum_def {} else {
4904 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4907 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4908 self.populate_module_if_necessary(enum_module);
4910 let mut variants = Vec::new();
4911 enum_module.for_each_child_stable(|ident, _, name_binding| {
4912 if let Def::Variant(..) = name_binding.def() {
4913 let mut segms = enum_import_suggestion.path.segments.clone();
4914 segms.push(ast::PathSegment::from_ident(ident));
4915 variants.push(Path {
4916 span: name_binding.span,
4925 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4926 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4927 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4928 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4932 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4934 ast::VisibilityKind::Public => ty::Visibility::Public,
4935 ast::VisibilityKind::Crate(..) => {
4936 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4938 ast::VisibilityKind::Inherited => {
4939 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4941 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4942 // For visibilities we are not ready to provide correct implementation of "uniform
4943 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4944 // On 2015 edition visibilities are resolved as crate-relative by default,
4945 // so we are prepending a root segment if necessary.
4946 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4947 let crate_root = if ident.is_path_segment_keyword() {
4949 } else if ident.span.rust_2018() {
4950 let msg = "relative paths are not supported in visibilities on 2018 edition";
4951 self.session.struct_span_err(ident.span, msg)
4955 format!("crate::{}", path),
4956 Applicability::MaybeIncorrect,
4959 return ty::Visibility::Public;
4961 let ctxt = ident.span.ctxt();
4962 Some(Segment::from_ident(Ident::new(
4963 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4967 let segments = crate_root.into_iter()
4968 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4969 let def = self.smart_resolve_path_fragment(
4974 PathSource::Visibility,
4975 CrateLint::SimplePath(id),
4977 if def == Def::Err {
4978 ty::Visibility::Public
4980 let vis = ty::Visibility::Restricted(def.def_id());
4981 if self.is_accessible(vis) {
4984 self.session.span_err(path.span, "visibilities can only be restricted \
4985 to ancestor modules");
4986 ty::Visibility::Public
4993 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4994 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4997 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4998 vis.is_accessible_from(module.normal_ancestor_id, self)
5001 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
5002 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
5003 if !ptr::eq(module, old_module) {
5004 span_bug!(binding.span, "parent module is reset for binding");
5009 fn disambiguate_legacy_vs_modern(
5011 legacy: &'a NameBinding<'a>,
5012 modern: &'a NameBinding<'a>,
5014 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
5015 // is disambiguated to mitigate regressions from macro modularization.
5016 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
5017 match (self.binding_parent_modules.get(&PtrKey(legacy)),
5018 self.binding_parent_modules.get(&PtrKey(modern))) {
5019 (Some(legacy), Some(modern)) =>
5020 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
5021 modern.is_ancestor_of(legacy),
5026 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
5027 if b.span.is_dummy() {
5028 let add_built_in = match b.def() {
5029 // These already contain the "built-in" prefix or look bad with it.
5030 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
5033 let (built_in, from) = if from_prelude {
5034 ("", " from prelude")
5035 } else if b.is_extern_crate() && !b.is_import() &&
5036 self.session.opts.externs.get(&ident.as_str()).is_some() {
5037 ("", " passed with `--extern`")
5038 } else if add_built_in {
5044 let article = if built_in.is_empty() { b.article() } else { "a" };
5045 format!("{a}{built_in} {thing}{from}",
5046 a = article, thing = b.descr(), built_in = built_in, from = from)
5048 let introduced = if b.is_import() { "imported" } else { "defined" };
5049 format!("the {thing} {introduced} here",
5050 thing = b.descr(), introduced = introduced)
5054 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
5055 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
5056 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
5057 // We have to print the span-less alternative first, otherwise formatting looks bad.
5058 (b2, b1, misc2, misc1, true)
5060 (b1, b2, misc1, misc2, false)
5063 let mut err = struct_span_err!(self.session, ident.span, E0659,
5064 "`{ident}` is ambiguous ({why})",
5065 ident = ident, why = kind.descr());
5066 err.span_label(ident.span, "ambiguous name");
5068 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
5069 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
5070 let note_msg = format!("`{ident}` could{also} refer to {what}",
5071 ident = ident, also = also, what = what);
5073 let mut help_msgs = Vec::new();
5074 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
5075 kind == AmbiguityKind::GlobVsExpanded ||
5076 kind == AmbiguityKind::GlobVsOuter &&
5077 swapped != also.is_empty()) {
5078 help_msgs.push(format!("consider adding an explicit import of \
5079 `{ident}` to disambiguate", ident = ident))
5081 if b.is_extern_crate() && ident.span.rust_2018() {
5082 help_msgs.push(format!(
5083 "use `::{ident}` to refer to this {thing} unambiguously",
5084 ident = ident, thing = b.descr(),
5087 if misc == AmbiguityErrorMisc::SuggestCrate {
5088 help_msgs.push(format!(
5089 "use `crate::{ident}` to refer to this {thing} unambiguously",
5090 ident = ident, thing = b.descr(),
5092 } else if misc == AmbiguityErrorMisc::SuggestSelf {
5093 help_msgs.push(format!(
5094 "use `self::{ident}` to refer to this {thing} unambiguously",
5095 ident = ident, thing = b.descr(),
5099 err.span_note(b.span, ¬e_msg);
5100 for (i, help_msg) in help_msgs.iter().enumerate() {
5101 let or = if i == 0 { "" } else { "or " };
5102 err.help(&format!("{}{}", or, help_msg));
5106 could_refer_to(b1, misc1, "");
5107 could_refer_to(b2, misc2, " also");
5111 fn report_errors(&mut self, krate: &Crate) {
5112 self.report_with_use_injections(krate);
5114 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
5115 let msg = "macro-expanded `macro_export` macros from the current crate \
5116 cannot be referred to by absolute paths";
5117 self.session.buffer_lint_with_diagnostic(
5118 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
5119 CRATE_NODE_ID, span_use, msg,
5120 lint::builtin::BuiltinLintDiagnostics::
5121 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
5125 for ambiguity_error in &self.ambiguity_errors {
5126 self.report_ambiguity_error(ambiguity_error);
5129 let mut reported_spans = FxHashSet::default();
5130 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
5131 if reported_spans.insert(dedup_span) {
5132 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
5133 binding.descr(), ident.name);
5138 fn report_with_use_injections(&mut self, krate: &Crate) {
5139 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5140 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5141 if !candidates.is_empty() {
5142 show_candidates(&mut err, span, &candidates, better, found_use);
5148 fn report_conflict<'b>(&mut self,
5152 new_binding: &NameBinding<'b>,
5153 old_binding: &NameBinding<'b>) {
5154 // Error on the second of two conflicting names
5155 if old_binding.span.lo() > new_binding.span.lo() {
5156 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5159 let container = match parent.kind {
5160 ModuleKind::Def(Def::Mod(_), _) => "module",
5161 ModuleKind::Def(Def::Trait(_), _) => "trait",
5162 ModuleKind::Block(..) => "block",
5166 let old_noun = match old_binding.is_import() {
5168 false => "definition",
5171 let new_participle = match new_binding.is_import() {
5176 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5178 if let Some(s) = self.name_already_seen.get(&name) {
5184 let old_kind = match (ns, old_binding.module()) {
5185 (ValueNS, _) => "value",
5186 (MacroNS, _) => "macro",
5187 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5188 (TypeNS, Some(module)) if module.is_normal() => "module",
5189 (TypeNS, Some(module)) if module.is_trait() => "trait",
5190 (TypeNS, _) => "type",
5193 let msg = format!("the name `{}` is defined multiple times", name);
5195 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5196 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5197 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5198 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5199 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5201 _ => match (old_binding.is_import(), new_binding.is_import()) {
5202 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5203 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5204 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5208 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5213 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5215 self.session.source_map().def_span(old_binding.span),
5216 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5219 // See https://github.com/rust-lang/rust/issues/32354
5220 use NameBindingKind::Import;
5221 let directive = match (&new_binding.kind, &old_binding.kind) {
5222 // If there are two imports where one or both have attributes then prefer removing the
5223 // import without attributes.
5224 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5225 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5226 (new.has_attributes || old.has_attributes)
5228 if old.has_attributes {
5229 Some((new, new_binding.span, true))
5231 Some((old, old_binding.span, true))
5234 // Otherwise prioritize the new binding.
5235 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5236 Some((directive, new_binding.span, other.is_import())),
5237 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5238 Some((directive, old_binding.span, other.is_import())),
5242 // Check if the target of the use for both bindings is the same.
5243 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5244 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5245 let from_item = self.extern_prelude.get(&ident)
5246 .map(|entry| entry.introduced_by_item)
5248 // Only suggest removing an import if both bindings are to the same def, if both spans
5249 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5250 // been introduced by a item.
5251 let should_remove_import = duplicate && !has_dummy_span &&
5252 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5255 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5256 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5257 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5258 // Simple case - remove the entire import. Due to the above match arm, this can
5259 // only be a single use so just remove it entirely.
5260 err.span_suggestion(
5261 directive.use_span_with_attributes,
5262 "remove unnecessary import",
5264 Applicability::MaybeIncorrect,
5267 Some((directive, span, _)) =>
5268 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5273 self.name_already_seen.insert(name, span);
5276 /// This function adds a suggestion to change the binding name of a new import that conflicts
5277 /// with an existing import.
5279 /// ```ignore (diagnostic)
5280 /// help: you can use `as` to change the binding name of the import
5282 /// LL | use foo::bar as other_bar;
5283 /// | ^^^^^^^^^^^^^^^^^^^^^
5285 fn add_suggestion_for_rename_of_use(
5287 err: &mut DiagnosticBuilder<'_>,
5289 directive: &ImportDirective<'_>,
5292 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5293 format!("Other{}", name)
5295 format!("other_{}", name)
5298 let mut suggestion = None;
5299 match directive.subclass {
5300 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5301 suggestion = Some(format!("self as {}", suggested_name)),
5302 ImportDirectiveSubclass::SingleImport { source, .. } => {
5303 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5304 .map(|pos| pos as usize) {
5305 if let Ok(snippet) = self.session.source_map()
5306 .span_to_snippet(binding_span) {
5307 if pos <= snippet.len() {
5308 suggestion = Some(format!(
5312 if snippet.ends_with(";") { ";" } else { "" }
5318 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5319 suggestion = Some(format!(
5320 "extern crate {} as {};",
5321 source.unwrap_or(target.name),
5324 _ => unreachable!(),
5327 let rename_msg = "you can use `as` to change the binding name of the import";
5328 if let Some(suggestion) = suggestion {
5329 err.span_suggestion(
5333 Applicability::MaybeIncorrect,
5336 err.span_label(binding_span, rename_msg);
5340 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5341 /// nested. In the following example, this function will be invoked to remove the `a` binding
5342 /// in the second use statement:
5344 /// ```ignore (diagnostic)
5345 /// use issue_52891::a;
5346 /// use issue_52891::{d, a, e};
5349 /// The following suggestion will be added:
5351 /// ```ignore (diagnostic)
5352 /// use issue_52891::{d, a, e};
5353 /// ^-- help: remove unnecessary import
5356 /// If the nested use contains only one import then the suggestion will remove the entire
5359 /// It is expected that the directive provided is a nested import - this isn't checked by the
5360 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5361 /// as characters expected by span manipulations won't be present.
5362 fn add_suggestion_for_duplicate_nested_use(
5364 err: &mut DiagnosticBuilder<'_>,
5365 directive: &ImportDirective<'_>,
5368 assert!(directive.is_nested());
5369 let message = "remove unnecessary import";
5370 let source_map = self.session.source_map();
5372 // Two examples will be used to illustrate the span manipulations we're doing:
5374 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5375 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5376 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5377 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5379 // Find the span of everything after the binding.
5380 // ie. `a, e};` or `a};`
5381 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5383 // Find everything after the binding but not including the binding.
5384 // ie. `, e};` or `};`
5385 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5387 // Keep characters in the span until we encounter something that isn't a comma or
5391 // Also note whether a closing brace character was encountered. If there
5392 // was, then later go backwards to remove any trailing commas that are left.
5393 let mut found_closing_brace = false;
5394 let after_binding_until_next_binding = source_map.span_take_while(
5395 after_binding_until_end,
5397 if ch == '}' { found_closing_brace = true; }
5398 ch == ' ' || ch == ','
5402 // Combine the two spans.
5403 // ie. `a, ` or `a`.
5405 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5406 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5408 // If there was a closing brace then identify the span to remove any trailing commas from
5409 // previous imports.
5410 if found_closing_brace {
5411 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5412 // `prev_source` will contain all of the source that came before the span.
5413 // Then split based on a command and take the first (ie. closest to our span)
5414 // snippet. In the example, this is a space.
5415 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5416 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5417 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5418 let prev_comma = prev_comma.first().unwrap();
5419 let prev_starting_brace = prev_starting_brace.first().unwrap();
5421 // If the amount of source code before the comma is greater than
5422 // the amount of source code before the starting brace then we've only
5423 // got one item in the nested item (eg. `issue_52891::{self}`).
5424 if prev_comma.len() > prev_starting_brace.len() {
5425 // So just remove the entire line...
5426 err.span_suggestion(
5427 directive.use_span_with_attributes,
5430 Applicability::MaybeIncorrect,
5435 let span = span.with_lo(BytePos(
5436 // Take away the number of bytes for the characters we've found and an
5437 // extra for the comma.
5438 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5440 err.span_suggestion(
5441 span, message, String::new(), Applicability::MaybeIncorrect,
5448 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5451 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5452 -> Option<&'a NameBinding<'a>> {
5453 if ident.is_path_segment_keyword() {
5454 // Make sure `self`, `super` etc produce an error when passed to here.
5457 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5458 if let Some(binding) = entry.extern_crate_item {
5459 if !speculative && entry.introduced_by_item {
5460 self.record_use(ident, TypeNS, binding, false);
5464 let crate_id = if !speculative {
5465 self.crate_loader.process_path_extern(ident.name, ident.span)
5466 } else if let Some(crate_id) =
5467 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5472 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5473 self.populate_module_if_necessary(&crate_root);
5474 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5475 .to_name_binding(self.arenas))
5481 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5482 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5485 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5486 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5489 fn names_to_string(idents: &[Ident]) -> String {
5490 let mut result = String::new();
5491 for (i, ident) in idents.iter()
5492 .filter(|ident| ident.name != keywords::PathRoot.name())
5495 result.push_str("::");
5497 result.push_str(&ident.as_str());
5502 fn path_names_to_string(path: &Path) -> String {
5503 names_to_string(&path.segments.iter()
5504 .map(|seg| seg.ident)
5505 .collect::<Vec<_>>())
5508 /// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5509 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5510 let variant_path = &suggestion.path;
5511 let variant_path_string = path_names_to_string(variant_path);
5513 let path_len = suggestion.path.segments.len();
5514 let enum_path = ast::Path {
5515 span: suggestion.path.span,
5516 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5518 let enum_path_string = path_names_to_string(&enum_path);
5520 (variant_path_string, enum_path_string)
5524 /// When an entity with a given name is not available in scope, we search for
5525 /// entities with that name in all crates. This method allows outputting the
5526 /// results of this search in a programmer-friendly way
5527 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5528 // This is `None` if all placement locations are inside expansions
5530 candidates: &[ImportSuggestion],
5534 // we want consistent results across executions, but candidates are produced
5535 // by iterating through a hash map, so make sure they are ordered:
5536 let mut path_strings: Vec<_> =
5537 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5538 path_strings.sort();
5540 let better = if better { "better " } else { "" };
5541 let msg_diff = match path_strings.len() {
5542 1 => " is found in another module, you can import it",
5543 _ => "s are found in other modules, you can import them",
5545 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5547 if let Some(span) = span {
5548 for candidate in &mut path_strings {
5549 // produce an additional newline to separate the new use statement
5550 // from the directly following item.
5551 let additional_newline = if found_use {
5556 *candidate = format!("use {};\n{}", candidate, additional_newline);
5559 err.span_suggestions(
5562 path_strings.into_iter(),
5563 Applicability::Unspecified,
5568 for candidate in path_strings {
5570 msg.push_str(&candidate);
5575 /// A somewhat inefficient routine to obtain the name of a module.
5576 fn module_to_string(module: Module<'_>) -> Option<String> {
5577 let mut names = Vec::new();
5579 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5580 if let ModuleKind::Def(_, name) = module.kind {
5581 if let Some(parent) = module.parent {
5582 names.push(Ident::with_empty_ctxt(name));
5583 collect_mod(names, parent);
5586 // danger, shouldn't be ident?
5587 names.push(Ident::from_str("<opaque>"));
5588 collect_mod(names, module.parent.unwrap());
5591 collect_mod(&mut names, module);
5593 if names.is_empty() {
5596 Some(names_to_string(&names.into_iter()
5598 .collect::<Vec<_>>()))
5601 fn err_path_resolution() -> PathResolution {
5602 PathResolution::new(Def::Err)
5605 #[derive(Copy, Clone, Debug)]
5607 /// Do not issue the lint
5610 /// This lint applies to some random path like `impl ::foo::Bar`
5611 /// or whatever. In this case, we can take the span of that path.
5614 /// This lint comes from a `use` statement. In this case, what we
5615 /// care about really is the *root* `use` statement; e.g., if we
5616 /// have nested things like `use a::{b, c}`, we care about the
5618 UsePath { root_id: NodeId, root_span: Span },
5620 /// This is the "trait item" from a fully qualified path. For example,
5621 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5622 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5623 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5627 fn node_id(&self) -> Option<NodeId> {
5629 CrateLint::No => None,
5630 CrateLint::SimplePath(id) |
5631 CrateLint::UsePath { root_id: id, .. } |
5632 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5637 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }