1 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
3 #![feature(crate_visibility_modifier)]
4 #![feature(label_break_value)]
6 #![feature(rustc_diagnostic_macros)]
7 #![feature(type_alias_enum_variants)]
9 #![recursion_limit="256"]
11 #![deny(rust_2018_idioms)]
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 self, PathResolution, CtorKind, CtorOf, NonMacroAttrKind, DefMap, ImportMap, ExportMap
27 use rustc::hir::def::Namespace::*;
28 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
29 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
30 use rustc::ty::{self, DefIdTree};
31 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
32 use rustc::{bug, span_bug};
34 use rustc_metadata::creader::CrateLoader;
35 use rustc_metadata::cstore::CStore;
37 use syntax::source_map::SourceMap;
38 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
39 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
40 use syntax::ext::base::SyntaxExtension;
41 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
42 use syntax::ext::base::MacroKind;
43 use syntax::symbol::{Symbol, keywords};
44 use syntax::util::lev_distance::find_best_match_for_name;
46 use syntax::visit::{self, FnKind, Visitor};
48 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
49 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
50 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
51 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
52 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
54 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
56 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
57 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
61 use std::cell::{Cell, RefCell};
62 use std::{cmp, fmt, iter, mem, ptr};
63 use std::collections::BTreeSet;
64 use std::mem::replace;
65 use rustc_data_structures::ptr_key::PtrKey;
66 use rustc_data_structures::sync::Lrc;
68 use error_reporting::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
69 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
70 use macros::{InvocationData, LegacyBinding, ParentScope};
72 type Def = def::Def<NodeId>;
74 // N.B., this module needs to be declared first so diagnostics are
75 // registered before they are used.
80 mod build_reduced_graph;
83 fn is_known_tool(name: Name) -> bool {
84 ["clippy", "rustfmt"].contains(&&*name.as_str())
94 AbsolutePath(Namespace),
99 /// A free importable items suggested in case of resolution failure.
100 struct ImportSuggestion {
105 /// A field or associated item from self type suggested in case of resolution failure.
106 enum AssocSuggestion {
113 struct BindingError {
115 origin: BTreeSet<Span>,
116 target: BTreeSet<Span>,
119 struct TypoSuggestion {
122 /// The kind of the binding ("crate", "module", etc.)
125 /// An appropriate article to refer to the binding ("a", "an", etc.)
126 article: &'static str,
129 impl PartialOrd for BindingError {
130 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
131 Some(self.cmp(other))
135 impl PartialEq for BindingError {
136 fn eq(&self, other: &BindingError) -> bool {
137 self.name == other.name
141 impl Ord for BindingError {
142 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
143 self.name.cmp(&other.name)
147 /// A vector of spans and replacements, a message and applicability.
148 type Suggestion = (Vec<(Span, String)>, String, Applicability);
150 enum ResolutionError<'a> {
151 /// Error E0401: can't use type or const parameters from outer function.
152 GenericParamsFromOuterFunction(Def),
153 /// Error E0403: the name is already used for a type or const parameter in this generic
155 NameAlreadyUsedInParameterList(Name, &'a Span),
156 /// Error E0407: method is not a member of trait.
157 MethodNotMemberOfTrait(Name, &'a str),
158 /// Error E0437: type is not a member of trait.
159 TypeNotMemberOfTrait(Name, &'a str),
160 /// Error E0438: const is not a member of trait.
161 ConstNotMemberOfTrait(Name, &'a str),
162 /// Error E0408: variable `{}` is not bound in all patterns.
163 VariableNotBoundInPattern(&'a BindingError),
164 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
165 VariableBoundWithDifferentMode(Name, Span),
166 /// Error E0415: identifier is bound more than once in this parameter list.
167 IdentifierBoundMoreThanOnceInParameterList(&'a str),
168 /// Error E0416: identifier is bound more than once in the same pattern.
169 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
170 /// Error E0426: use of undeclared label.
171 UndeclaredLabel(&'a str, Option<Name>),
172 /// Error E0429: `self` imports are only allowed within a `{ }` list.
173 SelfImportsOnlyAllowedWithin,
174 /// Error E0430: `self` import can only appear once in the list.
175 SelfImportCanOnlyAppearOnceInTheList,
176 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
177 SelfImportOnlyInImportListWithNonEmptyPrefix,
178 /// Error E0433: failed to resolve.
179 FailedToResolve { label: String, suggestion: Option<Suggestion> },
180 /// Error E0434: can't capture dynamic environment in a fn item.
181 CannotCaptureDynamicEnvironmentInFnItem,
182 /// Error E0435: attempt to use a non-constant value in a constant.
183 AttemptToUseNonConstantValueInConstant,
184 /// Error E0530: `X` bindings cannot shadow `Y`s.
185 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
186 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
187 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
190 /// Combines an error with provided span and emits it.
192 /// This takes the error provided, combines it with the span and any additional spans inside the
193 /// error and emits it.
194 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
196 resolution_error: ResolutionError<'a>) {
197 resolve_struct_error(resolver, span, resolution_error).emit();
200 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
202 resolution_error: ResolutionError<'a>)
203 -> DiagnosticBuilder<'sess> {
204 match resolution_error {
205 ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
206 let mut err = struct_span_err!(resolver.session,
209 "can't use generic parameters from outer function",
211 err.span_label(span, format!("use of generic parameter from outer function"));
213 let cm = resolver.session.source_map();
215 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
216 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
217 resolver.definitions.opt_span(def_id)
220 reduce_impl_span_to_impl_keyword(cm, impl_span),
221 "`Self` type implicitly declared here, by this `impl`",
224 match (maybe_trait_defid, maybe_impl_defid) {
226 err.span_label(span, "can't use `Self` here");
229 err.span_label(span, "use a type here instead");
231 (None, None) => bug!("`impl` without trait nor type?"),
235 Def::TyParam(def_id) => {
236 if let Some(span) = resolver.definitions.opt_span(def_id) {
237 err.span_label(span, "type variable from outer function");
240 Def::ConstParam(def_id) => {
241 if let Some(span) = resolver.definitions.opt_span(def_id) {
242 err.span_label(span, "const variable from outer function");
246 bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
251 // Try to retrieve the span of the function signature and generate a new message with
252 // a local type or const parameter.
253 let sugg_msg = &format!("try using a local generic parameter instead");
254 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
255 // Suggest the modification to the user
260 Applicability::MachineApplicable,
262 } else if let Some(sp) = cm.generate_fn_name_span(span) {
264 format!("try adding a local generic parameter in this method instead"));
266 err.help(&format!("try using a local generic parameter instead"));
271 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
272 let mut err = struct_span_err!(resolver.session,
275 "the name `{}` is already used for a generic \
276 parameter in this list of generic parameters",
278 err.span_label(span, "already used");
279 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
282 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
283 let mut err = struct_span_err!(resolver.session,
286 "method `{}` is not a member of trait `{}`",
289 err.span_label(span, format!("not a member of trait `{}`", trait_));
292 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
293 let mut err = struct_span_err!(resolver.session,
296 "type `{}` is not a member of trait `{}`",
299 err.span_label(span, format!("not a member of trait `{}`", trait_));
302 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
303 let mut err = struct_span_err!(resolver.session,
306 "const `{}` is not a member of trait `{}`",
309 err.span_label(span, format!("not a member of trait `{}`", trait_));
312 ResolutionError::VariableNotBoundInPattern(binding_error) => {
313 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
314 let msp = MultiSpan::from_spans(target_sp.clone());
315 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
316 let mut err = resolver.session.struct_span_err_with_code(
319 DiagnosticId::Error("E0408".into()),
321 for sp in target_sp {
322 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
324 let origin_sp = binding_error.origin.iter().cloned();
325 for sp in origin_sp {
326 err.span_label(sp, "variable not in all patterns");
330 ResolutionError::VariableBoundWithDifferentMode(variable_name,
331 first_binding_span) => {
332 let mut err = struct_span_err!(resolver.session,
335 "variable `{}` is bound in inconsistent \
336 ways within the same match arm",
338 err.span_label(span, "bound in different ways");
339 err.span_label(first_binding_span, "first binding");
342 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
343 let mut err = struct_span_err!(resolver.session,
346 "identifier `{}` is bound more than once in this parameter list",
348 err.span_label(span, "used as parameter more than once");
351 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
352 let mut err = struct_span_err!(resolver.session,
355 "identifier `{}` is bound more than once in the same pattern",
357 err.span_label(span, "used in a pattern more than once");
360 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
361 let mut err = struct_span_err!(resolver.session,
364 "use of undeclared label `{}`",
366 if let Some(lev_candidate) = lev_candidate {
367 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
369 err.span_label(span, format!("undeclared label `{}`", name));
373 ResolutionError::SelfImportsOnlyAllowedWithin => {
374 struct_span_err!(resolver.session,
378 "`self` imports are only allowed within a { } list")
380 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
381 let mut err = struct_span_err!(resolver.session, span, E0430,
382 "`self` import can only appear once in an import list");
383 err.span_label(span, "can only appear once in an import list");
386 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
387 let mut err = struct_span_err!(resolver.session, span, E0431,
388 "`self` import can only appear in an import list with \
389 a non-empty prefix");
390 err.span_label(span, "can only appear in an import list with a non-empty prefix");
393 ResolutionError::FailedToResolve { label, suggestion } => {
394 let mut err = struct_span_err!(resolver.session, span, E0433,
395 "failed to resolve: {}", &label);
396 err.span_label(span, label);
398 if let Some((suggestions, msg, applicability)) = suggestion {
399 err.multipart_suggestion(&msg, suggestions, applicability);
404 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
405 let mut err = struct_span_err!(resolver.session,
409 "can't capture dynamic environment in a fn item");
410 err.help("use the `|| { ... }` closure form instead");
413 ResolutionError::AttemptToUseNonConstantValueInConstant => {
414 let mut err = struct_span_err!(resolver.session, span, E0435,
415 "attempt to use a non-constant value in a constant");
416 err.span_label(span, "non-constant value");
419 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
420 let shadows_what = binding.descr();
421 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
422 what_binding, shadows_what);
423 err.span_label(span, format!("cannot be named the same as {} {}",
424 binding.article(), shadows_what));
425 let participle = if binding.is_import() { "imported" } else { "defined" };
426 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
427 err.span_label(binding.span, msg);
430 ResolutionError::ForwardDeclaredTyParam => {
431 let mut err = struct_span_err!(resolver.session, span, E0128,
432 "type parameters with a default cannot use \
433 forward declared identifiers");
435 span, "defaulted type parameters cannot be forward declared".to_string());
441 /// Adjust the impl span so that just the `impl` keyword is taken by removing
442 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
443 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
445 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
446 /// parser. If you need to use this function or something similar, please consider updating the
447 /// `source_map` functions and this function to something more robust.
448 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
449 let impl_span = cm.span_until_char(impl_span, '<');
450 let impl_span = cm.span_until_whitespace(impl_span);
454 #[derive(Copy, Clone, Debug)]
457 binding_mode: BindingMode,
460 /// Map from the name in a pattern to its binding mode.
461 type BindingMap = FxHashMap<Ident, BindingInfo>;
463 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
474 fn descr(self) -> &'static str {
476 PatternSource::Match => "match binding",
477 PatternSource::IfLet => "if let binding",
478 PatternSource::WhileLet => "while let binding",
479 PatternSource::Let => "let binding",
480 PatternSource::For => "for binding",
481 PatternSource::FnParam => "function parameter",
486 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
487 enum AliasPossibility {
492 #[derive(Copy, Clone, Debug)]
493 enum PathSource<'a> {
494 // Type paths `Path`.
496 // Trait paths in bounds or impls.
497 Trait(AliasPossibility),
498 // Expression paths `path`, with optional parent context.
499 Expr(Option<&'a Expr>),
500 // Paths in path patterns `Path`.
502 // Paths in struct expressions and patterns `Path { .. }`.
504 // Paths in tuple struct patterns `Path(..)`.
506 // `m::A::B` in `<T as m::A>::B::C`.
507 TraitItem(Namespace),
508 // Path in `pub(path)`
512 impl<'a> PathSource<'a> {
513 fn namespace(self) -> Namespace {
515 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
516 PathSource::Visibility => TypeNS,
517 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
518 PathSource::TraitItem(ns) => ns,
522 fn global_by_default(self) -> bool {
524 PathSource::Visibility => true,
525 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
526 PathSource::Struct | PathSource::TupleStruct |
527 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
531 fn defer_to_typeck(self) -> bool {
533 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
534 PathSource::Struct | PathSource::TupleStruct => true,
535 PathSource::Trait(_) | PathSource::TraitItem(..) |
536 PathSource::Visibility => false,
540 fn descr_expected(self) -> &'static str {
542 PathSource::Type => "type",
543 PathSource::Trait(_) => "trait",
544 PathSource::Pat => "unit struct/variant or constant",
545 PathSource::Struct => "struct, variant or union type",
546 PathSource::TupleStruct => "tuple struct/variant",
547 PathSource::Visibility => "module",
548 PathSource::TraitItem(ns) => match ns {
549 TypeNS => "associated type",
550 ValueNS => "method or associated constant",
551 MacroNS => bug!("associated macro"),
553 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
554 // "function" here means "anything callable" rather than `Def::Fn`,
555 // this is not precise but usually more helpful than just "value".
556 Some(&ExprKind::Call(..)) => "function",
562 fn is_expected(self, def: Def) -> bool {
564 PathSource::Type => match def {
565 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
566 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
567 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
568 Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
571 PathSource::Trait(AliasPossibility::No) => match def {
572 Def::Trait(..) => true,
575 PathSource::Trait(AliasPossibility::Maybe) => match def {
576 Def::Trait(..) => true,
577 Def::TraitAlias(..) => true,
580 PathSource::Expr(..) => match def {
581 Def::Ctor(_, _, CtorKind::Const) | Def::Ctor(_, _, CtorKind::Fn) |
582 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
583 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
584 Def::SelfCtor(..) | Def::ConstParam(..) => true,
587 PathSource::Pat => match def {
588 Def::Ctor(_, _, CtorKind::Const) |
589 Def::Const(..) | Def::AssociatedConst(..) |
590 Def::SelfCtor(..) => true,
593 PathSource::TupleStruct => match def {
594 Def::Ctor(_, _, CtorKind::Fn) | Def::SelfCtor(..) => true,
597 PathSource::Struct => match def {
598 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
599 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
602 PathSource::TraitItem(ns) => match def {
603 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
604 Def::AssociatedTy(..) if ns == TypeNS => true,
607 PathSource::Visibility => match def {
608 Def::Mod(..) => true,
614 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
615 __diagnostic_used!(E0404);
616 __diagnostic_used!(E0405);
617 __diagnostic_used!(E0412);
618 __diagnostic_used!(E0422);
619 __diagnostic_used!(E0423);
620 __diagnostic_used!(E0425);
621 __diagnostic_used!(E0531);
622 __diagnostic_used!(E0532);
623 __diagnostic_used!(E0573);
624 __diagnostic_used!(E0574);
625 __diagnostic_used!(E0575);
626 __diagnostic_used!(E0576);
627 __diagnostic_used!(E0577);
628 __diagnostic_used!(E0578);
629 match (self, has_unexpected_resolution) {
630 (PathSource::Trait(_), true) => "E0404",
631 (PathSource::Trait(_), false) => "E0405",
632 (PathSource::Type, true) => "E0573",
633 (PathSource::Type, false) => "E0412",
634 (PathSource::Struct, true) => "E0574",
635 (PathSource::Struct, false) => "E0422",
636 (PathSource::Expr(..), true) => "E0423",
637 (PathSource::Expr(..), false) => "E0425",
638 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
639 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
640 (PathSource::TraitItem(..), true) => "E0575",
641 (PathSource::TraitItem(..), false) => "E0576",
642 (PathSource::Visibility, true) => "E0577",
643 (PathSource::Visibility, false) => "E0578",
648 // A minimal representation of a path segment. We use this in resolve because
649 // we synthesize 'path segments' which don't have the rest of an AST or HIR
651 #[derive(Clone, Copy, Debug)]
658 fn from_path(path: &Path) -> Vec<Segment> {
659 path.segments.iter().map(|s| s.into()).collect()
662 fn from_ident(ident: Ident) -> Segment {
669 fn names_to_string(segments: &[Segment]) -> String {
670 names_to_string(&segments.iter()
671 .map(|seg| seg.ident)
672 .collect::<Vec<_>>())
676 impl<'a> From<&'a ast::PathSegment> for Segment {
677 fn from(seg: &'a ast::PathSegment) -> Segment {
685 struct UsePlacementFinder {
686 target_module: NodeId,
691 impl UsePlacementFinder {
692 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
693 let mut finder = UsePlacementFinder {
698 visit::walk_crate(&mut finder, krate);
699 (finder.span, finder.found_use)
703 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
706 module: &'tcx ast::Mod,
708 _: &[ast::Attribute],
711 if self.span.is_some() {
714 if node_id != self.target_module {
715 visit::walk_mod(self, module);
718 // find a use statement
719 for item in &module.items {
721 ItemKind::Use(..) => {
722 // don't suggest placing a use before the prelude
723 // import or other generated ones
724 if item.span.ctxt().outer().expn_info().is_none() {
725 self.span = Some(item.span.shrink_to_lo());
726 self.found_use = true;
730 // don't place use before extern crate
731 ItemKind::ExternCrate(_) => {}
732 // but place them before the first other item
733 _ => if self.span.map_or(true, |span| item.span < span ) {
734 if item.span.ctxt().outer().expn_info().is_none() {
735 // don't insert between attributes and an item
736 if item.attrs.is_empty() {
737 self.span = Some(item.span.shrink_to_lo());
739 // find the first attribute on the item
740 for attr in &item.attrs {
741 if self.span.map_or(true, |span| attr.span < span) {
742 self.span = Some(attr.span.shrink_to_lo());
753 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
754 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
755 fn visit_item(&mut self, item: &'tcx Item) {
756 self.resolve_item(item);
758 fn visit_arm(&mut self, arm: &'tcx Arm) {
759 self.resolve_arm(arm);
761 fn visit_block(&mut self, block: &'tcx Block) {
762 self.resolve_block(block);
764 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
765 debug!("visit_anon_const {:?}", constant);
766 self.with_constant_rib(|this| {
767 visit::walk_anon_const(this, constant);
770 fn visit_expr(&mut self, expr: &'tcx Expr) {
771 self.resolve_expr(expr, None);
773 fn visit_local(&mut self, local: &'tcx Local) {
774 self.resolve_local(local);
776 fn visit_ty(&mut self, ty: &'tcx Ty) {
778 TyKind::Path(ref qself, ref path) => {
779 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
781 TyKind::ImplicitSelf => {
782 let self_ty = keywords::SelfUpper.ident();
783 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
784 .map_or(Def::Err, |d| d.def());
785 self.record_def(ty.id, PathResolution::new(def));
789 visit::walk_ty(self, ty);
791 fn visit_poly_trait_ref(&mut self,
792 tref: &'tcx ast::PolyTraitRef,
793 m: &'tcx ast::TraitBoundModifier) {
794 self.smart_resolve_path(tref.trait_ref.ref_id, None,
795 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
796 visit::walk_poly_trait_ref(self, tref, m);
798 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
799 let generic_params = match foreign_item.node {
800 ForeignItemKind::Fn(_, ref generics) => {
801 HasGenericParams(generics, ItemRibKind)
803 ForeignItemKind::Static(..) => NoGenericParams,
804 ForeignItemKind::Ty => NoGenericParams,
805 ForeignItemKind::Macro(..) => NoGenericParams,
807 self.with_generic_param_rib(generic_params, |this| {
808 visit::walk_foreign_item(this, foreign_item);
811 fn visit_fn(&mut self,
812 function_kind: FnKind<'tcx>,
813 declaration: &'tcx FnDecl,
817 debug!("(resolving function) entering function");
818 let (rib_kind, asyncness) = match function_kind {
819 FnKind::ItemFn(_, ref header, ..) =>
820 (FnItemRibKind, header.asyncness.node),
821 FnKind::Method(_, ref sig, _, _) =>
822 (TraitOrImplItemRibKind, sig.header.asyncness.node),
823 FnKind::Closure(_) =>
824 // Async closures aren't resolved through `visit_fn`-- they're
825 // processed separately
826 (ClosureRibKind(node_id), IsAsync::NotAsync),
829 // Create a value rib for the function.
830 self.ribs[ValueNS].push(Rib::new(rib_kind));
832 // Create a label rib for the function.
833 self.label_ribs.push(Rib::new(rib_kind));
835 // Add each argument to the rib.
836 let mut bindings_list = FxHashMap::default();
837 for argument in &declaration.inputs {
838 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
840 self.visit_ty(&argument.ty);
842 debug!("(resolving function) recorded argument");
844 visit::walk_fn_ret_ty(self, &declaration.output);
846 // Resolve the function body, potentially inside the body of an async closure
847 if let IsAsync::Async { closure_id, .. } = asyncness {
848 let rib_kind = ClosureRibKind(closure_id);
849 self.ribs[ValueNS].push(Rib::new(rib_kind));
850 self.label_ribs.push(Rib::new(rib_kind));
853 match function_kind {
854 FnKind::ItemFn(.., body) |
855 FnKind::Method(.., body) => {
856 self.visit_block(body);
858 FnKind::Closure(body) => {
859 self.visit_expr(body);
863 // Leave the body of the async closure
864 if asyncness.is_async() {
865 self.label_ribs.pop();
866 self.ribs[ValueNS].pop();
869 debug!("(resolving function) leaving function");
871 self.label_ribs.pop();
872 self.ribs[ValueNS].pop();
875 fn visit_generics(&mut self, generics: &'tcx Generics) {
876 // For type parameter defaults, we have to ban access
877 // to following type parameters, as the InternalSubsts can only
878 // provide previous type parameters as they're built. We
879 // put all the parameters on the ban list and then remove
880 // them one by one as they are processed and become available.
881 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
882 let mut found_default = false;
883 default_ban_rib.bindings.extend(generics.params.iter()
884 .filter_map(|param| match param.kind {
885 GenericParamKind::Const { .. } |
886 GenericParamKind::Lifetime { .. } => None,
887 GenericParamKind::Type { ref default, .. } => {
888 found_default |= default.is_some();
890 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
897 for param in &generics.params {
899 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
900 GenericParamKind::Type { ref default, .. } => {
901 for bound in ¶m.bounds {
902 self.visit_param_bound(bound);
905 if let Some(ref ty) = default {
906 self.ribs[TypeNS].push(default_ban_rib);
908 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
911 // Allow all following defaults to refer to this type parameter.
912 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
914 GenericParamKind::Const { ref ty } => {
915 for bound in ¶m.bounds {
916 self.visit_param_bound(bound);
923 for p in &generics.where_clause.predicates {
924 self.visit_where_predicate(p);
929 #[derive(Copy, Clone)]
930 enum GenericParameters<'a, 'b> {
932 HasGenericParams(// Type parameters.
935 // The kind of the rib used for type parameters.
939 /// The rib kind controls the translation of local
940 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
941 #[derive(Copy, Clone, Debug)]
943 /// No translation needs to be applied.
946 /// We passed through a closure scope at the given `NodeId`.
947 /// Translate upvars as appropriate.
948 ClosureRibKind(NodeId /* func id */),
950 /// We passed through an impl or trait and are now in one of its
951 /// methods or associated types. Allow references to ty params that impl or trait
952 /// binds. Disallow any other upvars (including other ty params that are
954 TraitOrImplItemRibKind,
956 /// We passed through a function definition. Disallow upvars.
957 /// Permit only those const parameters that are specified in the function's generics.
960 /// We passed through an item scope. Disallow upvars.
963 /// We're in a constant item. Can't refer to dynamic stuff.
966 /// We passed through a module.
967 ModuleRibKind(Module<'a>),
969 /// We passed through a `macro_rules!` statement
970 MacroDefinition(DefId),
972 /// All bindings in this rib are type parameters that can't be used
973 /// from the default of a type parameter because they're not declared
974 /// before said type parameter. Also see the `visit_generics` override.
975 ForwardTyParamBanRibKind,
978 /// A single local scope.
980 /// A rib represents a scope names can live in. Note that these appear in many places, not just
981 /// around braces. At any place where the list of accessible names (of the given namespace)
982 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
983 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
986 /// Different [rib kinds](enum.RibKind) are transparent for different names.
988 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
989 /// resolving, the name is looked up from inside out.
992 bindings: FxHashMap<Ident, Def>,
997 fn new(kind: RibKind<'a>) -> Rib<'a> {
999 bindings: Default::default(),
1005 /// An intermediate resolution result.
1007 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
1008 /// items are visible in their whole block, while defs only from the place they are defined
1010 enum LexicalScopeBinding<'a> {
1011 Item(&'a NameBinding<'a>),
1015 impl<'a> LexicalScopeBinding<'a> {
1016 fn item(self) -> Option<&'a NameBinding<'a>> {
1018 LexicalScopeBinding::Item(binding) => Some(binding),
1023 fn def(self) -> Def {
1025 LexicalScopeBinding::Item(binding) => binding.def(),
1026 LexicalScopeBinding::Def(def) => def,
1031 #[derive(Copy, Clone, Debug)]
1032 enum ModuleOrUniformRoot<'a> {
1036 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1037 CrateRootAndExternPrelude,
1039 /// Virtual module that denotes resolution in extern prelude.
1040 /// Used for paths starting with `::` on 2018 edition.
1043 /// Virtual module that denotes resolution in current scope.
1044 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1045 /// are always split into two parts, the first of which should be some kind of module.
1049 impl ModuleOrUniformRoot<'_> {
1050 fn same_def(lhs: Self, rhs: Self) -> bool {
1052 (ModuleOrUniformRoot::Module(lhs),
1053 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1054 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1055 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1056 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1057 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1063 #[derive(Clone, Debug)]
1064 enum PathResult<'a> {
1065 Module(ModuleOrUniformRoot<'a>),
1066 NonModule(PathResolution),
1071 suggestion: Option<Suggestion>,
1072 is_error_from_last_segment: bool,
1077 /// An anonymous module; e.g., just a block.
1081 /// fn f() {} // (1)
1082 /// { // This is an anonymous module
1083 /// f(); // This resolves to (2) as we are inside the block.
1084 /// fn f() {} // (2)
1086 /// f(); // Resolves to (1)
1090 /// Any module with a name.
1094 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1095 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1101 /// Get name of the module.
1102 pub fn name(&self) -> Option<Name> {
1104 ModuleKind::Block(..) => None,
1105 ModuleKind::Def(_, name) => Some(*name),
1110 /// One node in the tree of modules.
1111 pub struct ModuleData<'a> {
1112 parent: Option<Module<'a>>,
1115 // The def id of the closest normal module (`mod`) ancestor (including this module).
1116 normal_ancestor_id: DefId,
1118 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1119 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1120 Option<&'a NameBinding<'a>>)>>,
1121 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1123 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1125 // Macro invocations that can expand into items in this module.
1126 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1128 no_implicit_prelude: bool,
1130 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1131 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1133 // Used to memoize the traits in this module for faster searches through all traits in scope.
1134 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1136 // Whether this module is populated. If not populated, any attempt to
1137 // access the children must be preceded with a
1138 // `populate_module_if_necessary` call.
1139 populated: Cell<bool>,
1141 /// Span of the module itself. Used for error reporting.
1147 type Module<'a> = &'a ModuleData<'a>;
1149 impl<'a> ModuleData<'a> {
1150 fn new(parent: Option<Module<'a>>,
1152 normal_ancestor_id: DefId,
1154 span: Span) -> Self {
1159 resolutions: Default::default(),
1160 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1161 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1162 builtin_attrs: RefCell::new(Vec::new()),
1163 unresolved_invocations: Default::default(),
1164 no_implicit_prelude: false,
1165 glob_importers: RefCell::new(Vec::new()),
1166 globs: RefCell::new(Vec::new()),
1167 traits: RefCell::new(None),
1168 populated: Cell::new(normal_ancestor_id.is_local()),
1174 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1175 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1176 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1180 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1181 let resolutions = self.resolutions.borrow();
1182 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1183 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1184 for &(&(ident, ns), &resolution) in resolutions.iter() {
1185 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1189 fn def(&self) -> Option<Def> {
1191 ModuleKind::Def(def, _) => Some(def),
1196 fn def_id(&self) -> Option<DefId> {
1197 self.def().as_ref().map(Def::def_id)
1200 // `self` resolves to the first module ancestor that `is_normal`.
1201 fn is_normal(&self) -> bool {
1203 ModuleKind::Def(Def::Mod(_), _) => true,
1208 fn is_trait(&self) -> bool {
1210 ModuleKind::Def(Def::Trait(_), _) => true,
1215 fn nearest_item_scope(&'a self) -> Module<'a> {
1216 if self.is_trait() { self.parent.unwrap() } else { self }
1219 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1220 while !ptr::eq(self, other) {
1221 if let Some(parent) = other.parent {
1231 impl<'a> fmt::Debug for ModuleData<'a> {
1232 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1233 write!(f, "{:?}", self.def())
1237 /// Records a possibly-private value, type, or module definition.
1238 #[derive(Clone, Debug)]
1239 pub struct NameBinding<'a> {
1240 kind: NameBindingKind<'a>,
1241 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1244 vis: ty::Visibility,
1247 pub trait ToNameBinding<'a> {
1248 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1251 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1252 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1257 #[derive(Clone, Debug)]
1258 enum NameBindingKind<'a> {
1259 Def(Def, /* is_macro_export */ bool),
1262 binding: &'a NameBinding<'a>,
1263 directive: &'a ImportDirective<'a>,
1268 impl<'a> NameBindingKind<'a> {
1269 /// Is this a name binding of a import?
1270 fn is_import(&self) -> bool {
1272 NameBindingKind::Import { .. } => true,
1278 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1280 struct UseError<'a> {
1281 err: DiagnosticBuilder<'a>,
1282 /// Attach `use` statements for these candidates.
1283 candidates: Vec<ImportSuggestion>,
1284 /// The `NodeId` of the module to place the use-statements in.
1286 /// Whether the diagnostic should state that it's "better".
1290 #[derive(Clone, Copy, PartialEq, Debug)]
1291 enum AmbiguityKind {
1295 LegacyHelperVsPrelude,
1300 MoreExpandedVsOuter,
1303 impl AmbiguityKind {
1304 fn descr(self) -> &'static str {
1306 AmbiguityKind::Import =>
1307 "name vs any other name during import resolution",
1308 AmbiguityKind::BuiltinAttr =>
1309 "built-in attribute vs any other name",
1310 AmbiguityKind::DeriveHelper =>
1311 "derive helper attribute vs any other name",
1312 AmbiguityKind::LegacyHelperVsPrelude =>
1313 "legacy plugin helper attribute vs name from prelude",
1314 AmbiguityKind::LegacyVsModern =>
1315 "`macro_rules` vs non-`macro_rules` from other module",
1316 AmbiguityKind::GlobVsOuter =>
1317 "glob import vs any other name from outer scope during import/macro resolution",
1318 AmbiguityKind::GlobVsGlob =>
1319 "glob import vs glob import in the same module",
1320 AmbiguityKind::GlobVsExpanded =>
1321 "glob import vs macro-expanded name in the same \
1322 module during import/macro resolution",
1323 AmbiguityKind::MoreExpandedVsOuter =>
1324 "macro-expanded name vs less macro-expanded name \
1325 from outer scope during import/macro resolution",
1330 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1331 #[derive(Clone, Copy, PartialEq)]
1332 enum AmbiguityErrorMisc {
1339 struct AmbiguityError<'a> {
1340 kind: AmbiguityKind,
1342 b1: &'a NameBinding<'a>,
1343 b2: &'a NameBinding<'a>,
1344 misc1: AmbiguityErrorMisc,
1345 misc2: AmbiguityErrorMisc,
1348 impl<'a> NameBinding<'a> {
1349 fn module(&self) -> Option<Module<'a>> {
1351 NameBindingKind::Module(module) => Some(module),
1352 NameBindingKind::Import { binding, .. } => binding.module(),
1357 fn def(&self) -> Def {
1359 NameBindingKind::Def(def, _) => def,
1360 NameBindingKind::Module(module) => module.def().unwrap(),
1361 NameBindingKind::Import { binding, .. } => binding.def(),
1365 fn is_ambiguity(&self) -> bool {
1366 self.ambiguity.is_some() || match self.kind {
1367 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1372 // We sometimes need to treat variants as `pub` for backwards compatibility.
1373 fn pseudo_vis(&self) -> ty::Visibility {
1374 if self.is_variant() && self.def().def_id().is_local() {
1375 ty::Visibility::Public
1381 fn is_variant(&self) -> bool {
1383 NameBindingKind::Def(Def::Variant(..), _) |
1384 NameBindingKind::Def(Def::Ctor(_, CtorOf::Variant, ..), _) => true,
1389 fn is_extern_crate(&self) -> bool {
1391 NameBindingKind::Import {
1392 directive: &ImportDirective {
1393 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1396 NameBindingKind::Module(
1397 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1398 ) => def_id.index == CRATE_DEF_INDEX,
1403 fn is_import(&self) -> bool {
1405 NameBindingKind::Import { .. } => true,
1410 fn is_glob_import(&self) -> bool {
1412 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1417 fn is_importable(&self) -> bool {
1419 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1424 fn is_macro_def(&self) -> bool {
1426 NameBindingKind::Def(Def::Macro(..), _) => true,
1431 fn macro_kind(&self) -> Option<MacroKind> {
1433 Def::Macro(_, kind) => Some(kind),
1434 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1439 fn descr(&self) -> &'static str {
1440 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1443 fn article(&self) -> &'static str {
1444 if self.is_extern_crate() { "an" } else { self.def().article() }
1447 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1448 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1449 // Then this function returns `true` if `self` may emerge from a macro *after* that
1450 // in some later round and screw up our previously found resolution.
1451 // See more detailed explanation in
1452 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1453 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1454 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1455 // Expansions are partially ordered, so "may appear after" is an inversion of
1456 // "certainly appears before or simultaneously" and includes unordered cases.
1457 let self_parent_expansion = self.expansion;
1458 let other_parent_expansion = binding.expansion;
1459 let certainly_before_other_or_simultaneously =
1460 other_parent_expansion.is_descendant_of(self_parent_expansion);
1461 let certainly_before_invoc_or_simultaneously =
1462 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1463 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1467 /// Interns the names of the primitive types.
1469 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1470 /// special handling, since they have no place of origin.
1472 struct PrimitiveTypeTable {
1473 primitive_types: FxHashMap<Name, PrimTy>,
1476 impl PrimitiveTypeTable {
1477 fn new() -> PrimitiveTypeTable {
1478 let mut table = PrimitiveTypeTable::default();
1480 table.intern("bool", Bool);
1481 table.intern("char", Char);
1482 table.intern("f32", Float(FloatTy::F32));
1483 table.intern("f64", Float(FloatTy::F64));
1484 table.intern("isize", Int(IntTy::Isize));
1485 table.intern("i8", Int(IntTy::I8));
1486 table.intern("i16", Int(IntTy::I16));
1487 table.intern("i32", Int(IntTy::I32));
1488 table.intern("i64", Int(IntTy::I64));
1489 table.intern("i128", Int(IntTy::I128));
1490 table.intern("str", Str);
1491 table.intern("usize", Uint(UintTy::Usize));
1492 table.intern("u8", Uint(UintTy::U8));
1493 table.intern("u16", Uint(UintTy::U16));
1494 table.intern("u32", Uint(UintTy::U32));
1495 table.intern("u64", Uint(UintTy::U64));
1496 table.intern("u128", Uint(UintTy::U128));
1500 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1501 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1505 #[derive(Debug, Default, Clone)]
1506 pub struct ExternPreludeEntry<'a> {
1507 extern_crate_item: Option<&'a NameBinding<'a>>,
1508 pub introduced_by_item: bool,
1511 /// The main resolver class.
1513 /// This is the visitor that walks the whole crate.
1514 pub struct Resolver<'a> {
1515 session: &'a Session,
1518 pub definitions: Definitions,
1520 graph_root: Module<'a>,
1522 prelude: Option<Module<'a>>,
1523 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1525 /// N.B., this is used only for better diagnostics, not name resolution itself.
1526 has_self: FxHashSet<DefId>,
1528 /// Names of fields of an item `DefId` accessible with dot syntax.
1529 /// Used for hints during error reporting.
1530 field_names: FxHashMap<DefId, Vec<Name>>,
1532 /// All imports known to succeed or fail.
1533 determined_imports: Vec<&'a ImportDirective<'a>>,
1535 /// All non-determined imports.
1536 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1538 /// The module that represents the current item scope.
1539 current_module: Module<'a>,
1541 /// The current set of local scopes for types and values.
1542 /// FIXME #4948: Reuse ribs to avoid allocation.
1543 ribs: PerNS<Vec<Rib<'a>>>,
1545 /// The current set of local scopes, for labels.
1546 label_ribs: Vec<Rib<'a>>,
1548 /// The trait that the current context can refer to.
1549 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1551 /// The current self type if inside an impl (used for better errors).
1552 current_self_type: Option<Ty>,
1554 /// The current self item if inside an ADT (used for better errors).
1555 current_self_item: Option<NodeId>,
1557 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1558 /// We are resolving a last import segment during import validation.
1559 last_import_segment: bool,
1560 /// This binding should be ignored during in-module resolution, so that we don't get
1561 /// "self-confirming" import resolutions during import validation.
1562 blacklisted_binding: Option<&'a NameBinding<'a>>,
1564 /// The idents for the primitive types.
1565 primitive_type_table: PrimitiveTypeTable,
1568 import_map: ImportMap,
1569 pub freevars: FreevarMap,
1570 freevars_seen: NodeMap<NodeMap<usize>>,
1571 pub export_map: ExportMap<NodeId>,
1572 pub trait_map: TraitMap,
1574 /// A map from nodes to anonymous modules.
1575 /// Anonymous modules are pseudo-modules that are implicitly created around items
1576 /// contained within blocks.
1578 /// For example, if we have this:
1586 /// There will be an anonymous module created around `g` with the ID of the
1587 /// entry block for `f`.
1588 block_map: NodeMap<Module<'a>>,
1589 module_map: FxHashMap<DefId, Module<'a>>,
1590 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1591 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1593 /// Maps glob imports to the names of items actually imported.
1594 pub glob_map: GlobMap,
1596 used_imports: FxHashSet<(NodeId, Namespace)>,
1597 pub maybe_unused_trait_imports: NodeSet,
1598 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1600 /// A list of labels as of yet unused. Labels will be removed from this map when
1601 /// they are used (in a `break` or `continue` statement)
1602 pub unused_labels: FxHashMap<NodeId, Span>,
1604 /// Privacy errors are delayed until the end in order to deduplicate them.
1605 privacy_errors: Vec<PrivacyError<'a>>,
1606 /// Ambiguity errors are delayed for deduplication.
1607 ambiguity_errors: Vec<AmbiguityError<'a>>,
1608 /// `use` injections are delayed for better placement and deduplication.
1609 use_injections: Vec<UseError<'a>>,
1610 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1611 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1613 arenas: &'a ResolverArenas<'a>,
1614 dummy_binding: &'a NameBinding<'a>,
1616 crate_loader: &'a mut CrateLoader<'a>,
1617 macro_names: FxHashSet<Ident>,
1618 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1619 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1620 pub all_macros: FxHashMap<Name, Def>,
1621 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1622 macro_defs: FxHashMap<Mark, DefId>,
1623 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1625 /// List of crate local macros that we need to warn about as being unused.
1626 /// Right now this only includes macro_rules! macros, and macros 2.0.
1627 unused_macros: FxHashSet<DefId>,
1629 /// Maps the `Mark` of an expansion to its containing module or block.
1630 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1632 /// Avoid duplicated errors for "name already defined".
1633 name_already_seen: FxHashMap<Name, Span>,
1635 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1637 /// Table for mapping struct IDs into struct constructor IDs,
1638 /// it's not used during normal resolution, only for better error reporting.
1639 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1641 /// Only used for better errors on `fn(): fn()`.
1642 current_type_ascription: Vec<Span>,
1644 injected_crate: Option<Module<'a>>,
1647 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1649 pub struct ResolverArenas<'a> {
1650 modules: arena::TypedArena<ModuleData<'a>>,
1651 local_modules: RefCell<Vec<Module<'a>>>,
1652 name_bindings: arena::TypedArena<NameBinding<'a>>,
1653 import_directives: arena::TypedArena<ImportDirective<'a>>,
1654 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1655 invocation_data: arena::TypedArena<InvocationData<'a>>,
1656 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1659 impl<'a> ResolverArenas<'a> {
1660 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1661 let module = self.modules.alloc(module);
1662 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1663 self.local_modules.borrow_mut().push(module);
1667 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1668 self.local_modules.borrow()
1670 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1671 self.name_bindings.alloc(name_binding)
1673 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1674 -> &'a ImportDirective<'_> {
1675 self.import_directives.alloc(import_directive)
1677 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1678 self.name_resolutions.alloc(Default::default())
1680 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1681 -> &'a InvocationData<'a> {
1682 self.invocation_data.alloc(expansion_data)
1684 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1685 self.legacy_bindings.alloc(binding)
1689 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1690 fn parent(self, id: DefId) -> Option<DefId> {
1692 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1693 _ => self.cstore.def_key(id).parent,
1694 }.map(|index| DefId { index, ..id })
1698 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1699 /// the resolver is no longer needed as all the relevant information is inline.
1700 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1701 fn resolve_hir_path(
1706 self.resolve_hir_path_cb(path, is_value,
1707 |resolver, span, error| resolve_error(resolver, span, error))
1710 fn resolve_str_path(
1713 crate_root: Option<&str>,
1714 components: &[&str],
1717 let root = if crate_root.is_some() {
1722 let segments = iter::once(root.ident())
1724 crate_root.into_iter()
1725 .chain(components.iter().cloned())
1726 .map(Ident::from_str)
1727 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1730 let path = ast::Path {
1735 self.resolve_hir_path(&path, is_value)
1738 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1739 self.def_map.get(&id).cloned()
1742 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1743 self.import_map.get(&id).cloned().unwrap_or_default()
1746 fn definitions(&mut self) -> &mut Definitions {
1747 &mut self.definitions
1751 impl<'a> Resolver<'a> {
1752 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1753 /// isn't something that can be returned because it can't be made to live that long,
1754 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1755 /// just that an error occurred.
1756 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1757 -> Result<hir::Path, ()> {
1758 let mut errored = false;
1760 let path = if path_str.starts_with("::") {
1763 segments: iter::once(keywords::PathRoot.ident())
1765 path_str.split("::").skip(1).map(Ident::from_str)
1767 .map(|i| self.new_ast_path_segment(i))
1775 .map(Ident::from_str)
1776 .map(|i| self.new_ast_path_segment(i))
1780 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1781 if errored || path.def == def::Def::Err {
1788 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1789 fn resolve_hir_path_cb<F>(
1795 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1797 let namespace = if is_value { ValueNS } else { TypeNS };
1798 let span = path.span;
1799 let segments = &path.segments;
1800 let path = Segment::from_path(&path);
1801 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1802 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1803 span, CrateLint::No) {
1804 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1805 module.def().unwrap(),
1806 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1807 path_res.base_def(),
1808 PathResult::NonModule(..) => {
1809 error_callback(self, span, ResolutionError::FailedToResolve {
1810 label: String::from("type-relative paths are not supported in this context"),
1815 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1816 PathResult::Failed { span, label, suggestion, .. } => {
1817 error_callback(self, span, ResolutionError::FailedToResolve {
1825 let segments: Vec<_> = segments.iter().map(|seg| {
1826 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1827 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(def::Def::Err, |p| {
1828 p.base_def().map_id(|_| panic!("unexpected node_id"))
1834 def: def.map_id(|_| panic!("unexpected node_id")),
1835 segments: segments.into(),
1839 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1840 let mut seg = ast::PathSegment::from_ident(ident);
1841 seg.id = self.session.next_node_id();
1846 impl<'a> Resolver<'a> {
1847 pub fn new(session: &'a Session,
1851 crate_loader: &'a mut CrateLoader<'a>,
1852 arenas: &'a ResolverArenas<'a>)
1854 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1855 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1856 let graph_root = arenas.alloc_module(ModuleData {
1857 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1858 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1860 let mut module_map = FxHashMap::default();
1861 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1863 let mut definitions = Definitions::new();
1864 DefCollector::new(&mut definitions, Mark::root())
1865 .collect_root(crate_name, session.local_crate_disambiguator());
1867 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1868 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1871 if !attr::contains_name(&krate.attrs, "no_core") {
1872 extern_prelude.insert(Ident::from_str("core"), Default::default());
1873 if !attr::contains_name(&krate.attrs, "no_std") {
1874 extern_prelude.insert(Ident::from_str("std"), Default::default());
1875 if session.rust_2018() {
1876 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1881 let mut invocations = FxHashMap::default();
1882 invocations.insert(Mark::root(),
1883 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1885 let mut macro_defs = FxHashMap::default();
1886 macro_defs.insert(Mark::root(), root_def_id);
1895 // The outermost module has def ID 0; this is not reflected in the
1901 has_self: FxHashSet::default(),
1902 field_names: FxHashMap::default(),
1904 determined_imports: Vec::new(),
1905 indeterminate_imports: Vec::new(),
1907 current_module: graph_root,
1909 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1910 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1911 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1913 label_ribs: Vec::new(),
1915 current_trait_ref: None,
1916 current_self_type: None,
1917 current_self_item: None,
1918 last_import_segment: false,
1919 blacklisted_binding: None,
1921 primitive_type_table: PrimitiveTypeTable::new(),
1923 def_map: Default::default(),
1924 import_map: Default::default(),
1925 freevars: Default::default(),
1926 freevars_seen: Default::default(),
1927 export_map: FxHashMap::default(),
1928 trait_map: Default::default(),
1930 block_map: Default::default(),
1931 extern_module_map: FxHashMap::default(),
1932 binding_parent_modules: FxHashMap::default(),
1934 glob_map: Default::default(),
1936 used_imports: FxHashSet::default(),
1937 maybe_unused_trait_imports: Default::default(),
1938 maybe_unused_extern_crates: Vec::new(),
1940 unused_labels: FxHashMap::default(),
1942 privacy_errors: Vec::new(),
1943 ambiguity_errors: Vec::new(),
1944 use_injections: Vec::new(),
1945 macro_expanded_macro_export_errors: BTreeSet::new(),
1948 dummy_binding: arenas.alloc_name_binding(NameBinding {
1949 kind: NameBindingKind::Def(Def::Err, false),
1951 expansion: Mark::root(),
1953 vis: ty::Visibility::Public,
1957 macro_names: FxHashSet::default(),
1958 builtin_macros: FxHashMap::default(),
1959 macro_use_prelude: FxHashMap::default(),
1960 all_macros: FxHashMap::default(),
1961 macro_map: FxHashMap::default(),
1964 local_macro_def_scopes: FxHashMap::default(),
1965 name_already_seen: FxHashMap::default(),
1966 potentially_unused_imports: Vec::new(),
1967 struct_constructors: Default::default(),
1968 unused_macros: FxHashSet::default(),
1969 current_type_ascription: Vec::new(),
1970 injected_crate: None,
1974 pub fn arenas() -> ResolverArenas<'a> {
1978 /// Runs the function on each namespace.
1979 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1985 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1987 match self.macro_defs.get(&ctxt.outer()) {
1988 Some(&def_id) => return def_id,
1989 None => ctxt.remove_mark(),
1994 /// Entry point to crate resolution.
1995 pub fn resolve_crate(&mut self, krate: &Crate) {
1996 ImportResolver { resolver: self }.finalize_imports();
1997 self.current_module = self.graph_root;
1998 self.finalize_current_module_macro_resolutions();
2000 visit::walk_crate(self, krate);
2002 check_unused::check_crate(self, krate);
2003 self.report_errors(krate);
2004 self.crate_loader.postprocess(krate);
2011 normal_ancestor_id: DefId,
2015 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
2016 self.arenas.alloc_module(module)
2019 fn record_use(&mut self, ident: Ident, ns: Namespace,
2020 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
2021 if let Some((b2, kind)) = used_binding.ambiguity {
2022 self.ambiguity_errors.push(AmbiguityError {
2023 kind, ident, b1: used_binding, b2,
2024 misc1: AmbiguityErrorMisc::None,
2025 misc2: AmbiguityErrorMisc::None,
2028 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
2029 // Avoid marking `extern crate` items that refer to a name from extern prelude,
2030 // but not introduce it, as used if they are accessed from lexical scope.
2031 if is_lexical_scope {
2032 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
2033 if let Some(crate_item) = entry.extern_crate_item {
2034 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2041 directive.used.set(true);
2042 self.used_imports.insert((directive.id, ns));
2043 self.add_to_glob_map(&directive, ident);
2044 self.record_use(ident, ns, binding, false);
2049 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2050 if directive.is_glob() {
2051 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2055 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2056 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2057 /// `ident` in the first scope that defines it (or None if no scopes define it).
2059 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2060 /// the items are defined in the block. For example,
2063 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2066 /// g(); // This resolves to the local variable `g` since it shadows the item.
2070 /// Invariant: This must only be called during main resolution, not during
2071 /// import resolution.
2072 fn resolve_ident_in_lexical_scope(&mut self,
2075 record_used_id: Option<NodeId>,
2077 -> Option<LexicalScopeBinding<'a>> {
2078 assert!(ns == TypeNS || ns == ValueNS);
2079 if ident.name == keywords::Invalid.name() {
2080 return Some(LexicalScopeBinding::Def(Def::Err));
2082 ident.span = if ident.name == keywords::SelfUpper.name() {
2083 // FIXME(jseyfried) improve `Self` hygiene
2084 ident.span.with_ctxt(SyntaxContext::empty())
2085 } else if ns == TypeNS {
2088 ident.span.modern_and_legacy()
2091 // Walk backwards up the ribs in scope.
2092 let record_used = record_used_id.is_some();
2093 let mut module = self.graph_root;
2094 for i in (0 .. self.ribs[ns].len()).rev() {
2095 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2096 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2097 // The ident resolves to a type parameter or local variable.
2098 return Some(LexicalScopeBinding::Def(
2099 self.adjust_local_def(ns, i, def, record_used, path_span)
2103 module = match self.ribs[ns][i].kind {
2104 ModuleRibKind(module) => module,
2105 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2106 // If an invocation of this macro created `ident`, give up on `ident`
2107 // and switch to `ident`'s source from the macro definition.
2108 ident.span.remove_mark();
2114 let item = self.resolve_ident_in_module_unadjusted(
2115 ModuleOrUniformRoot::Module(module),
2121 if let Ok(binding) = item {
2122 // The ident resolves to an item.
2123 return Some(LexicalScopeBinding::Item(binding));
2127 ModuleKind::Block(..) => {}, // We can see through blocks
2132 ident.span = ident.span.modern();
2133 let mut poisoned = None;
2135 let opt_module = if let Some(node_id) = record_used_id {
2136 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2137 node_id, &mut poisoned)
2139 self.hygienic_lexical_parent(module, &mut ident.span)
2141 module = unwrap_or!(opt_module, break);
2142 let orig_current_module = self.current_module;
2143 self.current_module = module; // Lexical resolutions can never be a privacy error.
2144 let result = self.resolve_ident_in_module_unadjusted(
2145 ModuleOrUniformRoot::Module(module),
2151 self.current_module = orig_current_module;
2155 if let Some(node_id) = poisoned {
2156 self.session.buffer_lint_with_diagnostic(
2157 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2158 node_id, ident.span,
2159 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2160 lint::builtin::BuiltinLintDiagnostics::
2161 ProcMacroDeriveResolutionFallback(ident.span),
2164 return Some(LexicalScopeBinding::Item(binding))
2166 Err(Determined) => continue,
2167 Err(Undetermined) =>
2168 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2172 if !module.no_implicit_prelude {
2174 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2175 return Some(LexicalScopeBinding::Item(binding));
2178 if ns == TypeNS && is_known_tool(ident.name) {
2179 let binding = (Def::ToolMod, ty::Visibility::Public,
2180 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2181 return Some(LexicalScopeBinding::Item(binding));
2183 if let Some(prelude) = self.prelude {
2184 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2185 ModuleOrUniformRoot::Module(prelude),
2191 return Some(LexicalScopeBinding::Item(binding));
2199 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2200 -> Option<Module<'a>> {
2201 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2202 return Some(self.macro_def_scope(span.remove_mark()));
2205 if let ModuleKind::Block(..) = module.kind {
2206 return Some(module.parent.unwrap());
2212 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2213 span: &mut Span, node_id: NodeId,
2214 poisoned: &mut Option<NodeId>)
2215 -> Option<Module<'a>> {
2216 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2220 // We need to support the next case under a deprecation warning
2223 // ---- begin: this comes from a proc macro derive
2224 // mod implementation_details {
2225 // // Note that `MyStruct` is not in scope here.
2226 // impl SomeTrait for MyStruct { ... }
2230 // So we have to fall back to the module's parent during lexical resolution in this case.
2231 if let Some(parent) = module.parent {
2232 // Inner module is inside the macro, parent module is outside of the macro.
2233 if module.expansion != parent.expansion &&
2234 module.expansion.is_descendant_of(parent.expansion) {
2235 // The macro is a proc macro derive
2236 if module.expansion.looks_like_proc_macro_derive() {
2237 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2238 *poisoned = Some(node_id);
2239 return module.parent;
2248 fn resolve_ident_in_module(
2250 module: ModuleOrUniformRoot<'a>,
2253 parent_scope: Option<&ParentScope<'a>>,
2256 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2257 self.resolve_ident_in_module_ext(
2258 module, ident, ns, parent_scope, record_used, path_span
2259 ).map_err(|(determinacy, _)| determinacy)
2262 fn resolve_ident_in_module_ext(
2264 module: ModuleOrUniformRoot<'a>,
2267 parent_scope: Option<&ParentScope<'a>>,
2270 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2271 let orig_current_module = self.current_module;
2273 ModuleOrUniformRoot::Module(module) => {
2274 ident.span = ident.span.modern();
2275 if let Some(def) = ident.span.adjust(module.expansion) {
2276 self.current_module = self.macro_def_scope(def);
2279 ModuleOrUniformRoot::ExternPrelude => {
2280 ident.span = ident.span.modern();
2281 ident.span.adjust(Mark::root());
2283 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2284 ModuleOrUniformRoot::CurrentScope => {
2288 let result = self.resolve_ident_in_module_unadjusted_ext(
2289 module, ident, ns, parent_scope, false, record_used, path_span,
2291 self.current_module = orig_current_module;
2295 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2296 let mut ctxt = ident.span.ctxt();
2297 let mark = if ident.name == keywords::DollarCrate.name() {
2298 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2299 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2300 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2301 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2302 // definitions actually produced by `macro` and `macro` definitions produced by
2303 // `macro_rules!`, but at least such configurations are not stable yet.
2304 ctxt = ctxt.modern_and_legacy();
2305 let mut iter = ctxt.marks().into_iter().rev().peekable();
2306 let mut result = None;
2307 // Find the last modern mark from the end if it exists.
2308 while let Some(&(mark, transparency)) = iter.peek() {
2309 if transparency == Transparency::Opaque {
2310 result = Some(mark);
2316 // Then find the last legacy mark from the end if it exists.
2317 for (mark, transparency) in iter {
2318 if transparency == Transparency::SemiTransparent {
2319 result = Some(mark);
2326 ctxt = ctxt.modern();
2327 ctxt.adjust(Mark::root())
2329 let module = match mark {
2330 Some(def) => self.macro_def_scope(def),
2331 None => return self.graph_root,
2333 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2336 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2337 let mut module = self.get_module(module.normal_ancestor_id);
2338 while module.span.ctxt().modern() != *ctxt {
2339 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2340 module = self.get_module(parent.normal_ancestor_id);
2347 // We maintain a list of value ribs and type ribs.
2349 // Simultaneously, we keep track of the current position in the module
2350 // graph in the `current_module` pointer. When we go to resolve a name in
2351 // the value or type namespaces, we first look through all the ribs and
2352 // then query the module graph. When we resolve a name in the module
2353 // namespace, we can skip all the ribs (since nested modules are not
2354 // allowed within blocks in Rust) and jump straight to the current module
2357 // Named implementations are handled separately. When we find a method
2358 // call, we consult the module node to find all of the implementations in
2359 // scope. This information is lazily cached in the module node. We then
2360 // generate a fake "implementation scope" containing all the
2361 // implementations thus found, for compatibility with old resolve pass.
2363 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2364 where F: FnOnce(&mut Resolver<'_>) -> T
2366 let id = self.definitions.local_def_id(id);
2367 let module = self.module_map.get(&id).cloned(); // clones a reference
2368 if let Some(module) = module {
2369 // Move down in the graph.
2370 let orig_module = replace(&mut self.current_module, module);
2371 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2372 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2374 self.finalize_current_module_macro_resolutions();
2377 self.current_module = orig_module;
2378 self.ribs[ValueNS].pop();
2379 self.ribs[TypeNS].pop();
2386 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2387 /// is returned by the given predicate function
2389 /// Stops after meeting a closure.
2390 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2391 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2393 for rib in self.label_ribs.iter().rev() {
2396 // If an invocation of this macro created `ident`, give up on `ident`
2397 // and switch to `ident`'s source from the macro definition.
2398 MacroDefinition(def) => {
2399 if def == self.macro_def(ident.span.ctxt()) {
2400 ident.span.remove_mark();
2404 // Do not resolve labels across function boundary
2408 let r = pred(rib, ident);
2416 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2417 debug!("resolve_adt");
2418 self.with_current_self_item(item, |this| {
2419 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2420 let item_def_id = this.definitions.local_def_id(item.id);
2421 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2422 visit::walk_item(this, item);
2428 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2429 let segments = &use_tree.prefix.segments;
2430 if !segments.is_empty() {
2431 let ident = segments[0].ident;
2432 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2436 let nss = match use_tree.kind {
2437 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2440 let report_error = |this: &Self, ns| {
2441 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2442 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2446 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2447 Some(LexicalScopeBinding::Def(..)) => {
2448 report_error(self, ns);
2450 Some(LexicalScopeBinding::Item(binding)) => {
2451 let orig_blacklisted_binding =
2452 mem::replace(&mut self.blacklisted_binding, Some(binding));
2453 if let Some(LexicalScopeBinding::Def(..)) =
2454 self.resolve_ident_in_lexical_scope(ident, ns, None,
2455 use_tree.prefix.span) {
2456 report_error(self, ns);
2458 self.blacklisted_binding = orig_blacklisted_binding;
2463 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2464 for (use_tree, _) in use_trees {
2465 self.future_proof_import(use_tree);
2470 fn resolve_item(&mut self, item: &Item) {
2471 let name = item.ident.name;
2472 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2475 ItemKind::Ty(_, ref generics) |
2476 ItemKind::Fn(_, _, ref generics, _) |
2477 ItemKind::Existential(_, ref generics) => {
2478 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2479 |this| visit::walk_item(this, item));
2482 ItemKind::Enum(_, ref generics) |
2483 ItemKind::Struct(_, ref generics) |
2484 ItemKind::Union(_, ref generics) => {
2485 self.resolve_adt(item, generics);
2488 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2489 self.resolve_implementation(generics,
2495 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2496 // Create a new rib for the trait-wide type parameters.
2497 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2498 let local_def_id = this.definitions.local_def_id(item.id);
2499 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2500 this.visit_generics(generics);
2501 walk_list!(this, visit_param_bound, bounds);
2503 for trait_item in trait_items {
2504 let generic_params = HasGenericParams(&trait_item.generics,
2505 TraitOrImplItemRibKind);
2506 this.with_generic_param_rib(generic_params, |this| {
2507 match trait_item.node {
2508 TraitItemKind::Const(ref ty, ref default) => {
2511 // Only impose the restrictions of
2512 // ConstRibKind for an actual constant
2513 // expression in a provided default.
2514 if let Some(ref expr) = *default{
2515 this.with_constant_rib(|this| {
2516 this.visit_expr(expr);
2520 TraitItemKind::Method(_, _) => {
2521 visit::walk_trait_item(this, trait_item)
2523 TraitItemKind::Type(..) => {
2524 visit::walk_trait_item(this, trait_item)
2526 TraitItemKind::Macro(_) => {
2527 panic!("unexpanded macro in resolve!")
2536 ItemKind::TraitAlias(ref generics, ref bounds) => {
2537 // Create a new rib for the trait-wide type parameters.
2538 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2539 let local_def_id = this.definitions.local_def_id(item.id);
2540 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2541 this.visit_generics(generics);
2542 walk_list!(this, visit_param_bound, bounds);
2547 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2548 self.with_scope(item.id, |this| {
2549 visit::walk_item(this, item);
2553 ItemKind::Static(ref ty, _, ref expr) |
2554 ItemKind::Const(ref ty, ref expr) => {
2555 debug!("resolve_item ItemKind::Const");
2556 self.with_item_rib(|this| {
2558 this.with_constant_rib(|this| {
2559 this.visit_expr(expr);
2564 ItemKind::Use(ref use_tree) => {
2565 self.future_proof_import(use_tree);
2568 ItemKind::ExternCrate(..) |
2569 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2570 // do nothing, these are just around to be encoded
2573 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2577 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2578 where F: FnOnce(&mut Resolver<'_>)
2580 debug!("with_generic_param_rib");
2581 match generic_params {
2582 HasGenericParams(generics, rib_kind) => {
2583 let mut function_type_rib = Rib::new(rib_kind);
2584 let mut function_value_rib = Rib::new(rib_kind);
2585 let mut seen_bindings = FxHashMap::default();
2586 for param in &generics.params {
2588 GenericParamKind::Lifetime { .. } => {}
2589 GenericParamKind::Type { .. } => {
2590 let ident = param.ident.modern();
2591 debug!("with_generic_param_rib: {}", param.id);
2593 if seen_bindings.contains_key(&ident) {
2594 let span = seen_bindings.get(&ident).unwrap();
2595 let err = ResolutionError::NameAlreadyUsedInParameterList(
2599 resolve_error(self, param.ident.span, err);
2601 seen_bindings.entry(ident).or_insert(param.ident.span);
2603 // Plain insert (no renaming).
2604 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2605 function_type_rib.bindings.insert(ident, def);
2606 self.record_def(param.id, PathResolution::new(def));
2608 GenericParamKind::Const { .. } => {
2609 let ident = param.ident.modern();
2610 debug!("with_generic_param_rib: {}", param.id);
2612 if seen_bindings.contains_key(&ident) {
2613 let span = seen_bindings.get(&ident).unwrap();
2614 let err = ResolutionError::NameAlreadyUsedInParameterList(
2618 resolve_error(self, param.ident.span, err);
2620 seen_bindings.entry(ident).or_insert(param.ident.span);
2622 let def = Def::ConstParam(self.definitions.local_def_id(param.id));
2623 function_value_rib.bindings.insert(ident, def);
2624 self.record_def(param.id, PathResolution::new(def));
2628 self.ribs[ValueNS].push(function_value_rib);
2629 self.ribs[TypeNS].push(function_type_rib);
2632 NoGenericParams => {
2639 if let HasGenericParams(..) = generic_params {
2640 self.ribs[TypeNS].pop();
2641 self.ribs[ValueNS].pop();
2645 fn with_label_rib<F>(&mut self, f: F)
2646 where F: FnOnce(&mut Resolver<'_>)
2648 self.label_ribs.push(Rib::new(NormalRibKind));
2650 self.label_ribs.pop();
2653 fn with_item_rib<F>(&mut self, f: F)
2654 where F: FnOnce(&mut Resolver<'_>)
2656 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2657 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2659 self.ribs[TypeNS].pop();
2660 self.ribs[ValueNS].pop();
2663 fn with_constant_rib<F>(&mut self, f: F)
2664 where F: FnOnce(&mut Resolver<'_>)
2666 debug!("with_constant_rib");
2667 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2668 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2670 self.label_ribs.pop();
2671 self.ribs[ValueNS].pop();
2674 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2675 where F: FnOnce(&mut Resolver<'_>) -> T
2677 // Handle nested impls (inside fn bodies)
2678 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2679 let result = f(self);
2680 self.current_self_type = previous_value;
2684 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2685 where F: FnOnce(&mut Resolver<'_>) -> T
2687 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2688 let result = f(self);
2689 self.current_self_item = previous_value;
2693 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2694 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2695 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2697 let mut new_val = None;
2698 let mut new_id = None;
2699 if let Some(trait_ref) = opt_trait_ref {
2700 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2701 let def = self.smart_resolve_path_fragment(
2705 trait_ref.path.span,
2706 PathSource::Trait(AliasPossibility::No),
2707 CrateLint::SimplePath(trait_ref.ref_id),
2709 if def != Def::Err {
2710 new_id = Some(def.def_id());
2711 let span = trait_ref.path.span;
2712 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2713 self.resolve_path_without_parent_scope(
2718 CrateLint::SimplePath(trait_ref.ref_id),
2721 new_val = Some((module, trait_ref.clone()));
2725 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2726 let result = f(self, new_id);
2727 self.current_trait_ref = original_trait_ref;
2731 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2732 where F: FnOnce(&mut Resolver<'_>)
2734 let mut self_type_rib = Rib::new(NormalRibKind);
2736 // Plain insert (no renaming, since types are not currently hygienic)
2737 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2738 self.ribs[TypeNS].push(self_type_rib);
2740 self.ribs[TypeNS].pop();
2743 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2744 where F: FnOnce(&mut Resolver<'_>)
2746 let self_def = Def::SelfCtor(impl_id);
2747 let mut self_type_rib = Rib::new(NormalRibKind);
2748 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2749 self.ribs[ValueNS].push(self_type_rib);
2751 self.ribs[ValueNS].pop();
2754 fn resolve_implementation(&mut self,
2755 generics: &Generics,
2756 opt_trait_reference: &Option<TraitRef>,
2759 impl_items: &[ImplItem]) {
2760 debug!("resolve_implementation");
2761 // If applicable, create a rib for the type parameters.
2762 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2763 // Dummy self type for better errors if `Self` is used in the trait path.
2764 this.with_self_rib(Def::SelfTy(None, None), |this| {
2765 // Resolve the trait reference, if necessary.
2766 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2767 let item_def_id = this.definitions.local_def_id(item_id);
2768 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2769 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2770 // Resolve type arguments in the trait path.
2771 visit::walk_trait_ref(this, trait_ref);
2773 // Resolve the self type.
2774 this.visit_ty(self_type);
2775 // Resolve the generic parameters.
2776 this.visit_generics(generics);
2777 // Resolve the items within the impl.
2778 this.with_current_self_type(self_type, |this| {
2779 this.with_self_struct_ctor_rib(item_def_id, |this| {
2780 debug!("resolve_implementation with_self_struct_ctor_rib");
2781 for impl_item in impl_items {
2782 this.resolve_visibility(&impl_item.vis);
2784 // We also need a new scope for the impl item type parameters.
2785 let generic_params = HasGenericParams(&impl_item.generics,
2786 TraitOrImplItemRibKind);
2787 this.with_generic_param_rib(generic_params, |this| {
2788 use self::ResolutionError::*;
2789 match impl_item.node {
2790 ImplItemKind::Const(..) => {
2792 "resolve_implementation ImplItemKind::Const",
2794 // If this is a trait impl, ensure the const
2796 this.check_trait_item(
2800 |n, s| ConstNotMemberOfTrait(n, s),
2803 this.with_constant_rib(|this| {
2804 visit::walk_impl_item(this, impl_item)
2807 ImplItemKind::Method(..) => {
2808 // If this is a trait impl, ensure the method
2810 this.check_trait_item(impl_item.ident,
2813 |n, s| MethodNotMemberOfTrait(n, s));
2815 visit::walk_impl_item(this, impl_item);
2817 ImplItemKind::Type(ref ty) => {
2818 // If this is a trait impl, ensure the type
2820 this.check_trait_item(impl_item.ident,
2823 |n, s| TypeNotMemberOfTrait(n, s));
2827 ImplItemKind::Existential(ref bounds) => {
2828 // If this is a trait impl, ensure the type
2830 this.check_trait_item(impl_item.ident,
2833 |n, s| TypeNotMemberOfTrait(n, s));
2835 for bound in bounds {
2836 this.visit_param_bound(bound);
2839 ImplItemKind::Macro(_) =>
2840 panic!("unexpanded macro in resolve!"),
2852 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2853 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2855 // If there is a TraitRef in scope for an impl, then the method must be in the
2857 if let Some((module, _)) = self.current_trait_ref {
2858 if self.resolve_ident_in_module(
2859 ModuleOrUniformRoot::Module(module),
2866 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2867 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2872 fn resolve_local(&mut self, local: &Local) {
2873 // Resolve the type.
2874 walk_list!(self, visit_ty, &local.ty);
2876 // Resolve the initializer.
2877 walk_list!(self, visit_expr, &local.init);
2879 // Resolve the pattern.
2880 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2883 // build a map from pattern identifiers to binding-info's.
2884 // this is done hygienically. This could arise for a macro
2885 // that expands into an or-pattern where one 'x' was from the
2886 // user and one 'x' came from the macro.
2887 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2888 let mut binding_map = FxHashMap::default();
2890 pat.walk(&mut |pat| {
2891 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2892 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2893 Some(Def::Local(..)) => true,
2896 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2897 binding_map.insert(ident, binding_info);
2906 // check that all of the arms in an or-pattern have exactly the
2907 // same set of bindings, with the same binding modes for each.
2908 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2909 if pats.is_empty() {
2913 let mut missing_vars = FxHashMap::default();
2914 let mut inconsistent_vars = FxHashMap::default();
2915 for (i, p) in pats.iter().enumerate() {
2916 let map_i = self.binding_mode_map(&p);
2918 for (j, q) in pats.iter().enumerate() {
2923 let map_j = self.binding_mode_map(&q);
2924 for (&key, &binding_i) in &map_i {
2925 if map_j.is_empty() { // Account for missing bindings when
2926 let binding_error = missing_vars // map_j has none.
2928 .or_insert(BindingError {
2930 origin: BTreeSet::new(),
2931 target: BTreeSet::new(),
2933 binding_error.origin.insert(binding_i.span);
2934 binding_error.target.insert(q.span);
2936 for (&key_j, &binding_j) in &map_j {
2937 match map_i.get(&key_j) {
2938 None => { // missing binding
2939 let binding_error = missing_vars
2941 .or_insert(BindingError {
2943 origin: BTreeSet::new(),
2944 target: BTreeSet::new(),
2946 binding_error.origin.insert(binding_j.span);
2947 binding_error.target.insert(p.span);
2949 Some(binding_i) => { // check consistent binding
2950 if binding_i.binding_mode != binding_j.binding_mode {
2953 .or_insert((binding_j.span, binding_i.span));
2961 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2962 missing_vars.sort();
2963 for (_, v) in missing_vars {
2965 *v.origin.iter().next().unwrap(),
2966 ResolutionError::VariableNotBoundInPattern(v));
2968 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2969 inconsistent_vars.sort();
2970 for (name, v) in inconsistent_vars {
2971 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2975 fn resolve_arm(&mut self, arm: &Arm) {
2976 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2978 let mut bindings_list = FxHashMap::default();
2979 for pattern in &arm.pats {
2980 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2983 // This has to happen *after* we determine which pat_idents are variants.
2984 self.check_consistent_bindings(&arm.pats);
2986 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2987 self.visit_expr(expr)
2989 self.visit_expr(&arm.body);
2991 self.ribs[ValueNS].pop();
2994 fn resolve_block(&mut self, block: &Block) {
2995 debug!("(resolving block) entering block");
2996 // Move down in the graph, if there's an anonymous module rooted here.
2997 let orig_module = self.current_module;
2998 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
3000 let mut num_macro_definition_ribs = 0;
3001 if let Some(anonymous_module) = anonymous_module {
3002 debug!("(resolving block) found anonymous module, moving down");
3003 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3004 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
3005 self.current_module = anonymous_module;
3006 self.finalize_current_module_macro_resolutions();
3008 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3011 // Descend into the block.
3012 for stmt in &block.stmts {
3013 if let ast::StmtKind::Item(ref item) = stmt.node {
3014 if let ast::ItemKind::MacroDef(..) = item.node {
3015 num_macro_definition_ribs += 1;
3016 let def = self.definitions.local_def_id(item.id);
3017 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
3018 self.label_ribs.push(Rib::new(MacroDefinition(def)));
3022 self.visit_stmt(stmt);
3026 self.current_module = orig_module;
3027 for _ in 0 .. num_macro_definition_ribs {
3028 self.ribs[ValueNS].pop();
3029 self.label_ribs.pop();
3031 self.ribs[ValueNS].pop();
3032 if anonymous_module.is_some() {
3033 self.ribs[TypeNS].pop();
3035 debug!("(resolving block) leaving block");
3038 fn fresh_binding(&mut self,
3041 outer_pat_id: NodeId,
3042 pat_src: PatternSource,
3043 bindings: &mut FxHashMap<Ident, NodeId>)
3045 // Add the binding to the local ribs, if it
3046 // doesn't already exist in the bindings map. (We
3047 // must not add it if it's in the bindings map
3048 // because that breaks the assumptions later
3049 // passes make about or-patterns.)
3050 let ident = ident.modern_and_legacy();
3051 let mut def = Def::Local(pat_id);
3052 match bindings.get(&ident).cloned() {
3053 Some(id) if id == outer_pat_id => {
3054 // `Variant(a, a)`, error
3058 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3062 Some(..) if pat_src == PatternSource::FnParam => {
3063 // `fn f(a: u8, a: u8)`, error
3067 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3071 Some(..) if pat_src == PatternSource::Match ||
3072 pat_src == PatternSource::IfLet ||
3073 pat_src == PatternSource::WhileLet => {
3074 // `Variant1(a) | Variant2(a)`, ok
3075 // Reuse definition from the first `a`.
3076 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3079 span_bug!(ident.span, "two bindings with the same name from \
3080 unexpected pattern source {:?}", pat_src);
3083 // A completely fresh binding, add to the lists if it's valid.
3084 if ident.name != keywords::Invalid.name() {
3085 bindings.insert(ident, outer_pat_id);
3086 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3091 PathResolution::new(def)
3094 fn resolve_pattern(&mut self,
3096 pat_src: PatternSource,
3097 // Maps idents to the node ID for the
3098 // outermost pattern that binds them.
3099 bindings: &mut FxHashMap<Ident, NodeId>) {
3100 // Visit all direct subpatterns of this pattern.
3101 let outer_pat_id = pat.id;
3102 pat.walk(&mut |pat| {
3103 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3105 PatKind::Ident(bmode, ident, ref opt_pat) => {
3106 // First try to resolve the identifier as some existing
3107 // entity, then fall back to a fresh binding.
3108 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3110 .and_then(LexicalScopeBinding::item);
3111 let resolution = binding.map(NameBinding::def).and_then(|def| {
3112 let is_syntactic_ambiguity = opt_pat.is_none() &&
3113 bmode == BindingMode::ByValue(Mutability::Immutable);
3115 Def::Ctor(_, _, CtorKind::Const) |
3116 Def::Const(..) if is_syntactic_ambiguity => {
3117 // Disambiguate in favor of a unit struct/variant
3118 // or constant pattern.
3119 self.record_use(ident, ValueNS, binding.unwrap(), false);
3120 Some(PathResolution::new(def))
3122 Def::Ctor(..) | Def::Const(..) | Def::Static(..) => {
3123 // This is unambiguously a fresh binding, either syntactically
3124 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3125 // to something unusable as a pattern (e.g., constructor function),
3126 // but we still conservatively report an error, see
3127 // issues/33118#issuecomment-233962221 for one reason why.
3131 ResolutionError::BindingShadowsSomethingUnacceptable(
3132 pat_src.descr(), ident.name, binding.unwrap())
3136 Def::Fn(..) | Def::Err => {
3137 // These entities are explicitly allowed
3138 // to be shadowed by fresh bindings.
3142 span_bug!(ident.span, "unexpected definition for an \
3143 identifier in pattern: {:?}", def);
3146 }).unwrap_or_else(|| {
3147 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3150 self.record_def(pat.id, resolution);
3153 PatKind::TupleStruct(ref path, ..) => {
3154 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3157 PatKind::Path(ref qself, ref path) => {
3158 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3161 PatKind::Struct(ref path, ..) => {
3162 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3170 visit::walk_pat(self, pat);
3173 // High-level and context dependent path resolution routine.
3174 // Resolves the path and records the resolution into definition map.
3175 // If resolution fails tries several techniques to find likely
3176 // resolution candidates, suggest imports or other help, and report
3177 // errors in user friendly way.
3178 fn smart_resolve_path(&mut self,
3180 qself: Option<&QSelf>,
3182 source: PathSource<'_>)
3184 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3187 /// A variant of `smart_resolve_path` where you also specify extra
3188 /// information about where the path came from; this extra info is
3189 /// sometimes needed for the lint that recommends rewriting
3190 /// absolute paths to `crate`, so that it knows how to frame the
3191 /// suggestion. If you are just resolving a path like `foo::bar`
3192 /// that appears in an arbitrary location, then you just want
3193 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3194 /// already provides.
3195 fn smart_resolve_path_with_crate_lint(
3198 qself: Option<&QSelf>,
3200 source: PathSource<'_>,
3201 crate_lint: CrateLint
3202 ) -> PathResolution {
3203 self.smart_resolve_path_fragment(
3206 &Segment::from_path(path),
3213 fn smart_resolve_path_fragment(&mut self,
3215 qself: Option<&QSelf>,
3218 source: PathSource<'_>,
3219 crate_lint: CrateLint)
3221 let ns = source.namespace();
3222 let is_expected = &|def| source.is_expected(def);
3224 let report_errors = |this: &mut Self, def: Option<Def>| {
3225 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, def);
3226 let def_id = this.current_module.normal_ancestor_id;
3227 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3228 let better = def.is_some();
3229 this.use_injections.push(UseError { err, candidates, node_id, better });
3230 err_path_resolution()
3233 let resolution = match self.resolve_qpath_anywhere(
3239 source.defer_to_typeck(),
3240 source.global_by_default(),
3243 Some(resolution) if resolution.unresolved_segments() == 0 => {
3244 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3247 // Add a temporary hack to smooth the transition to new struct ctor
3248 // visibility rules. See #38932 for more details.
3250 if let Def::Struct(def_id) = resolution.base_def() {
3251 if let Some((ctor_def, ctor_vis))
3252 = self.struct_constructors.get(&def_id).cloned() {
3253 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3254 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3255 self.session.buffer_lint(lint, id, span,
3256 "private struct constructors are not usable through \
3257 re-exports in outer modules",
3259 res = Some(PathResolution::new(ctor_def));
3264 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3267 Some(resolution) if source.defer_to_typeck() => {
3268 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3269 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3270 // it needs to be added to the trait map.
3272 let item_name = path.last().unwrap().ident;
3273 let traits = self.get_traits_containing_item(item_name, ns);
3274 self.trait_map.insert(id, traits);
3278 _ => report_errors(self, None)
3281 if let PathSource::TraitItem(..) = source {} else {
3282 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3283 self.record_def(id, resolution);
3288 /// Only used in a specific case of type ascription suggestions
3290 fn get_colon_suggestion_span(&self, start: Span) -> Span {
3291 let cm = self.session.source_map();
3292 start.to(cm.next_point(start))
3295 fn type_ascription_suggestion(
3297 err: &mut DiagnosticBuilder<'_>,
3300 debug!("type_ascription_suggetion {:?}", base_span);
3301 let cm = self.session.source_map();
3302 let base_snippet = cm.span_to_snippet(base_span);
3303 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3304 if let Some(sp) = self.current_type_ascription.last() {
3307 // Try to find the `:`; bail on first non-':' / non-whitespace.
3308 sp = cm.next_point(sp);
3309 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3310 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3311 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3313 let mut show_label = true;
3314 if line_sp != line_base_sp {
3315 err.span_suggestion_short(
3317 "did you mean to use `;` here instead?",
3319 Applicability::MaybeIncorrect,
3322 let colon_sp = self.get_colon_suggestion_span(sp);
3323 let after_colon_sp = self.get_colon_suggestion_span(
3324 colon_sp.shrink_to_hi(),
3326 if !cm.span_to_snippet(after_colon_sp).map(|s| s == " ")
3329 err.span_suggestion(
3331 "maybe you meant to write a path separator here",
3333 Applicability::MaybeIncorrect,
3337 if let Ok(base_snippet) = base_snippet {
3338 let mut sp = after_colon_sp;
3340 // Try to find an assignment
3341 sp = cm.next_point(sp);
3342 let snippet = cm.span_to_snippet(sp.to(cm.next_point(sp)));
3344 Ok(ref x) if x.as_str() == "=" => {
3345 err.span_suggestion(
3347 "maybe you meant to write an assignment here",
3348 format!("let {}", base_snippet),
3349 Applicability::MaybeIncorrect,
3354 Ok(ref x) if x.as_str() == "\n" => break,
3362 err.span_label(base_span,
3363 "expecting a type here because of type ascription");
3366 } else if !snippet.trim().is_empty() {
3367 debug!("tried to find type ascription `:` token, couldn't find it");
3377 fn self_type_is_available(&mut self, span: Span) -> bool {
3378 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3379 TypeNS, None, span);
3380 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3383 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3384 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3385 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3386 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3389 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3390 fn resolve_qpath_anywhere(&mut self,
3392 qself: Option<&QSelf>,
3394 primary_ns: Namespace,
3396 defer_to_typeck: bool,
3397 global_by_default: bool,
3398 crate_lint: CrateLint)
3399 -> Option<PathResolution> {
3400 let mut fin_res = None;
3401 // FIXME: can't resolve paths in macro namespace yet, macros are
3402 // processed by the little special hack below.
3403 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3404 if i == 0 || ns != primary_ns {
3405 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3406 // If defer_to_typeck, then resolution > no resolution,
3407 // otherwise full resolution > partial resolution > no resolution.
3408 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3410 res => if fin_res.is_none() { fin_res = res },
3414 if primary_ns != MacroNS &&
3415 (self.macro_names.contains(&path[0].ident.modern()) ||
3416 self.builtin_macros.get(&path[0].ident.name).cloned()
3417 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3418 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3419 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3420 // Return some dummy definition, it's enough for error reporting.
3422 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3428 /// Handles paths that may refer to associated items.
3429 fn resolve_qpath(&mut self,
3431 qself: Option<&QSelf>,
3435 global_by_default: bool,
3436 crate_lint: CrateLint)
3437 -> Option<PathResolution> {
3439 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3440 ns={:?}, span={:?}, global_by_default={:?})",
3449 if let Some(qself) = qself {
3450 if qself.position == 0 {
3451 // This is a case like `<T>::B`, where there is no
3452 // trait to resolve. In that case, we leave the `B`
3453 // segment to be resolved by type-check.
3454 return Some(PathResolution::with_unresolved_segments(
3455 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3459 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3461 // Currently, `path` names the full item (`A::B::C`, in
3462 // our example). so we extract the prefix of that that is
3463 // the trait (the slice upto and including
3464 // `qself.position`). And then we recursively resolve that,
3465 // but with `qself` set to `None`.
3467 // However, setting `qself` to none (but not changing the
3468 // span) loses the information about where this path
3469 // *actually* appears, so for the purposes of the crate
3470 // lint we pass along information that this is the trait
3471 // name from a fully qualified path, and this also
3472 // contains the full span (the `CrateLint::QPathTrait`).
3473 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3474 let res = self.smart_resolve_path_fragment(
3477 &path[..=qself.position],
3479 PathSource::TraitItem(ns),
3480 CrateLint::QPathTrait {
3482 qpath_span: qself.path_span,
3486 // The remaining segments (the `C` in our example) will
3487 // have to be resolved by type-check, since that requires doing
3488 // trait resolution.
3489 return Some(PathResolution::with_unresolved_segments(
3490 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3494 let result = match self.resolve_path_without_parent_scope(
3501 PathResult::NonModule(path_res) => path_res,
3502 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3503 PathResolution::new(module.def().unwrap())
3505 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3506 // don't report an error right away, but try to fallback to a primitive type.
3507 // So, we are still able to successfully resolve something like
3509 // use std::u8; // bring module u8 in scope
3510 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3511 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3512 // // not to non-existent std::u8::max_value
3515 // Such behavior is required for backward compatibility.
3516 // The same fallback is used when `a` resolves to nothing.
3517 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3518 PathResult::Failed { .. }
3519 if (ns == TypeNS || path.len() > 1) &&
3520 self.primitive_type_table.primitive_types
3521 .contains_key(&path[0].ident.name) => {
3522 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3523 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3525 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3526 PathResolution::new(module.def().unwrap()),
3527 PathResult::Failed { is_error_from_last_segment: false, span, label, suggestion } => {
3528 resolve_error(self, span, ResolutionError::FailedToResolve { label, suggestion });
3529 err_path_resolution()
3531 PathResult::Module(..) | PathResult::Failed { .. } => return None,
3532 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3535 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3536 path[0].ident.name != keywords::PathRoot.name() &&
3537 path[0].ident.name != keywords::DollarCrate.name() {
3538 let unqualified_result = {
3539 match self.resolve_path_without_parent_scope(
3540 &[*path.last().unwrap()],
3546 PathResult::NonModule(path_res) => path_res.base_def(),
3547 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3548 module.def().unwrap(),
3549 _ => return Some(result),
3552 if result.base_def() == unqualified_result {
3553 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3554 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3561 fn resolve_path_without_parent_scope(
3564 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3567 crate_lint: CrateLint,
3568 ) -> PathResult<'a> {
3569 // Macro and import paths must have full parent scope available during resolution,
3570 // other paths will do okay with parent module alone.
3571 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3572 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3573 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3579 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3580 parent_scope: &ParentScope<'a>,
3583 crate_lint: CrateLint,
3584 ) -> PathResult<'a> {
3585 let mut module = None;
3586 let mut allow_super = true;
3587 let mut second_binding = None;
3588 self.current_module = parent_scope.module;
3591 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3592 path_span={:?}, crate_lint={:?})",
3600 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3601 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3602 let record_segment_def = |this: &mut Self, def| {
3604 if let Some(id) = id {
3605 if !this.def_map.contains_key(&id) {
3606 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3607 this.record_def(id, PathResolution::new(def));
3613 let is_last = i == path.len() - 1;
3614 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3615 let name = ident.name;
3617 allow_super &= ns == TypeNS &&
3618 (name == keywords::SelfLower.name() ||
3619 name == keywords::Super.name());
3622 if allow_super && name == keywords::Super.name() {
3623 let mut ctxt = ident.span.ctxt().modern();
3624 let self_module = match i {
3625 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3627 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3631 if let Some(self_module) = self_module {
3632 if let Some(parent) = self_module.parent {
3633 module = Some(ModuleOrUniformRoot::Module(
3634 self.resolve_self(&mut ctxt, parent)));
3638 let msg = "there are too many initial `super`s.".to_string();
3639 return PathResult::Failed {
3643 is_error_from_last_segment: false,
3647 if name == keywords::SelfLower.name() {
3648 let mut ctxt = ident.span.ctxt().modern();
3649 module = Some(ModuleOrUniformRoot::Module(
3650 self.resolve_self(&mut ctxt, self.current_module)));
3653 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3654 module = Some(ModuleOrUniformRoot::ExternPrelude);
3657 if name == keywords::PathRoot.name() &&
3658 ident.span.rust_2015() && self.session.rust_2018() {
3659 // `::a::b` from 2015 macro on 2018 global edition
3660 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3663 if name == keywords::PathRoot.name() ||
3664 name == keywords::Crate.name() ||
3665 name == keywords::DollarCrate.name() {
3666 // `::a::b`, `crate::a::b` or `$crate::a::b`
3667 module = Some(ModuleOrUniformRoot::Module(
3668 self.resolve_crate_root(ident)));
3674 // Report special messages for path segment keywords in wrong positions.
3675 if ident.is_path_segment_keyword() && i != 0 {
3676 let name_str = if name == keywords::PathRoot.name() {
3677 "crate root".to_string()
3679 format!("`{}`", name)
3681 let label = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3682 format!("global paths cannot start with {}", name_str)
3684 format!("{} in paths can only be used in start position", name_str)
3686 return PathResult::Failed {
3690 is_error_from_last_segment: false,
3694 let binding = if let Some(module) = module {
3695 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3696 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3697 assert!(ns == TypeNS);
3698 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3699 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3700 record_used, path_span)
3702 let record_used_id =
3703 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3704 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3705 // we found a locally-imported or available item/module
3706 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3707 // we found a local variable or type param
3708 Some(LexicalScopeBinding::Def(def))
3709 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3710 record_segment_def(self, def);
3711 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3715 _ => Err(Determinacy::determined(record_used)),
3722 second_binding = Some(binding);
3724 let def = binding.def();
3725 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3726 if let Some(next_module) = binding.module() {
3727 module = Some(ModuleOrUniformRoot::Module(next_module));
3728 record_segment_def(self, def);
3729 } else if def == Def::ToolMod && i + 1 != path.len() {
3730 if binding.is_import() {
3731 self.session.struct_span_err(
3732 ident.span, "cannot use a tool module through an import"
3734 binding.span, "the tool module imported here"
3737 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3738 return PathResult::NonModule(PathResolution::new(def));
3739 } else if def == Def::Err {
3740 return PathResult::NonModule(err_path_resolution());
3741 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3742 self.lint_if_path_starts_with_module(
3748 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3749 def, path.len() - i - 1
3752 let label = format!(
3753 "`{}` is {} {}, not a module",
3759 return PathResult::Failed {
3763 is_error_from_last_segment: is_last,
3767 Err(Undetermined) => return PathResult::Indeterminate,
3768 Err(Determined) => {
3769 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3770 if opt_ns.is_some() && !module.is_normal() {
3771 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3772 module.def().unwrap(), path.len() - i
3776 let module_def = match module {
3777 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3780 let (label, suggestion) = if module_def == self.graph_root.def() {
3781 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3782 let mut candidates =
3783 self.lookup_import_candidates(ident, TypeNS, is_mod);
3784 candidates.sort_by_cached_key(|c| {
3785 (c.path.segments.len(), c.path.to_string())
3787 if let Some(candidate) = candidates.get(0) {
3789 String::from("unresolved import"),
3791 vec![(ident.span, candidate.path.to_string())],
3792 String::from("a similar path exists"),
3793 Applicability::MaybeIncorrect,
3796 } else if !ident.is_reserved() {
3797 (format!("maybe a missing `extern crate {};`?", ident), None)
3799 // the parser will already have complained about the keyword being used
3800 return PathResult::NonModule(err_path_resolution());
3803 (format!("use of undeclared type or module `{}`", ident), None)
3805 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
3807 return PathResult::Failed {
3811 is_error_from_last_segment: is_last,
3817 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3819 PathResult::Module(match module {
3820 Some(module) => module,
3821 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3822 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3826 fn lint_if_path_starts_with_module(
3828 crate_lint: CrateLint,
3831 second_binding: Option<&NameBinding<'_>>,
3833 let (diag_id, diag_span) = match crate_lint {
3834 CrateLint::No => return,
3835 CrateLint::SimplePath(id) => (id, path_span),
3836 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3837 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3840 let first_name = match path.get(0) {
3841 // In the 2018 edition this lint is a hard error, so nothing to do
3842 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3846 // We're only interested in `use` paths which should start with
3847 // `{{root}}` currently.
3848 if first_name != keywords::PathRoot.name() {
3853 // If this import looks like `crate::...` it's already good
3854 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3855 // Otherwise go below to see if it's an extern crate
3857 // If the path has length one (and it's `PathRoot` most likely)
3858 // then we don't know whether we're gonna be importing a crate or an
3859 // item in our crate. Defer this lint to elsewhere
3863 // If the first element of our path was actually resolved to an
3864 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3865 // warning, this looks all good!
3866 if let Some(binding) = second_binding {
3867 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3868 // Careful: we still want to rewrite paths from
3869 // renamed extern crates.
3870 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3876 let diag = lint::builtin::BuiltinLintDiagnostics
3877 ::AbsPathWithModule(diag_span);
3878 self.session.buffer_lint_with_diagnostic(
3879 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3881 "absolute paths must start with `self`, `super`, \
3882 `crate`, or an external crate name in the 2018 edition",
3886 // Resolve a local definition, potentially adjusting for closures.
3887 fn adjust_local_def(&mut self,
3892 span: Span) -> Def {
3893 debug!("adjust_local_def");
3894 let ribs = &self.ribs[ns][rib_index + 1..];
3896 // An invalid forward use of a type parameter from a previous default.
3897 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3899 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3901 assert_eq!(def, Def::Err);
3907 span_bug!(span, "unexpected {:?} in bindings", def)
3909 Def::Local(node_id) => {
3910 use ResolutionError::*;
3911 let mut res_err = None;
3915 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3916 ForwardTyParamBanRibKind => {
3917 // Nothing to do. Continue.
3919 ClosureRibKind(function_id) => {
3922 let seen = self.freevars_seen
3925 if let Some(&index) = seen.get(&node_id) {
3926 def = Def::Upvar(node_id, index, function_id);
3929 let vec = self.freevars
3932 let depth = vec.len();
3933 def = Def::Upvar(node_id, depth, function_id);
3940 seen.insert(node_id, depth);
3943 ItemRibKind | FnItemRibKind | TraitOrImplItemRibKind => {
3944 // This was an attempt to access an upvar inside a
3945 // named function item. This is not allowed, so we
3948 // We don't immediately trigger a resolve error, because
3949 // we want certain other resolution errors (namely those
3950 // emitted for `ConstantItemRibKind` below) to take
3952 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
3955 ConstantItemRibKind => {
3956 // Still doesn't deal with upvars
3958 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
3964 if let Some(res_err) = res_err {
3965 resolve_error(self, span, res_err);
3969 Def::TyParam(..) | Def::SelfTy(..) => {
3972 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3973 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3974 ConstantItemRibKind => {
3975 // Nothing to do. Continue.
3977 ItemRibKind | FnItemRibKind => {
3978 // This was an attempt to use a type parameter outside its scope.
3983 ResolutionError::GenericParamsFromOuterFunction(def),
3991 Def::ConstParam(..) => {
3992 let mut ribs = ribs.iter().peekable();
3993 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
3994 // When declaring const parameters inside function signatures, the first rib
3995 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
3996 // (spuriously) conflicting with the const param.
4000 if let ItemRibKind | FnItemRibKind = rib.kind {
4001 // This was an attempt to use a const parameter outside its scope.
4006 ResolutionError::GenericParamsFromOuterFunction(def),
4018 fn lookup_assoc_candidate<FilterFn>(&mut self,
4021 filter_fn: FilterFn)
4022 -> Option<AssocSuggestion>
4023 where FilterFn: Fn(Def) -> bool
4025 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4027 TyKind::Path(None, _) => Some(t.id),
4028 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4029 // This doesn't handle the remaining `Ty` variants as they are not
4030 // that commonly the self_type, it might be interesting to provide
4031 // support for those in future.
4036 // Fields are generally expected in the same contexts as locals.
4037 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4038 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4039 // Look for a field with the same name in the current self_type.
4040 if let Some(resolution) = self.def_map.get(&node_id) {
4041 match resolution.base_def() {
4042 Def::Struct(did) | Def::Union(did)
4043 if resolution.unresolved_segments() == 0 => {
4044 if let Some(field_names) = self.field_names.get(&did) {
4045 if field_names.iter().any(|&field_name| ident.name == field_name) {
4046 return Some(AssocSuggestion::Field);
4056 // Look for associated items in the current trait.
4057 if let Some((module, _)) = self.current_trait_ref {
4058 if let Ok(binding) = self.resolve_ident_in_module(
4059 ModuleOrUniformRoot::Module(module),
4066 let def = binding.def();
4068 return Some(if self.has_self.contains(&def.def_id()) {
4069 AssocSuggestion::MethodWithSelf
4071 AssocSuggestion::AssocItem
4080 fn lookup_typo_candidate<FilterFn>(
4084 filter_fn: FilterFn,
4086 ) -> Option<TypoSuggestion>
4088 FilterFn: Fn(Def) -> bool,
4090 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4091 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4092 if let Some(binding) = resolution.borrow().binding {
4093 if filter_fn(binding.def()) {
4094 names.push(TypoSuggestion {
4095 candidate: ident.name,
4096 article: binding.def().article(),
4097 kind: binding.def().kind_name(),
4104 let mut names = Vec::new();
4105 if path.len() == 1 {
4106 // Search in lexical scope.
4107 // Walk backwards up the ribs in scope and collect candidates.
4108 for rib in self.ribs[ns].iter().rev() {
4109 // Locals and type parameters
4110 for (ident, def) in &rib.bindings {
4111 if filter_fn(*def) {
4112 names.push(TypoSuggestion {
4113 candidate: ident.name,
4114 article: def.article(),
4115 kind: def.kind_name(),
4120 if let ModuleRibKind(module) = rib.kind {
4121 // Items from this module
4122 add_module_candidates(module, &mut names);
4124 if let ModuleKind::Block(..) = module.kind {
4125 // We can see through blocks
4127 // Items from the prelude
4128 if !module.no_implicit_prelude {
4129 names.extend(self.extern_prelude.clone().iter().flat_map(|(ident, _)| {
4131 .maybe_process_path_extern(ident.name, ident.span)
4132 .and_then(|crate_id| {
4133 let crate_mod = Def::Mod(DefId {
4135 index: CRATE_DEF_INDEX,
4138 if filter_fn(crate_mod) {
4139 Some(TypoSuggestion {
4140 candidate: ident.name,
4150 if let Some(prelude) = self.prelude {
4151 add_module_candidates(prelude, &mut names);
4158 // Add primitive types to the mix
4159 if filter_fn(Def::PrimTy(Bool)) {
4161 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4165 kind: "primitive type",
4171 // Search in module.
4172 let mod_path = &path[..path.len() - 1];
4173 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4174 mod_path, Some(TypeNS), false, span, CrateLint::No
4176 if let ModuleOrUniformRoot::Module(module) = module {
4177 add_module_candidates(module, &mut names);
4182 let name = path[path.len() - 1].ident.name;
4183 // Make sure error reporting is deterministic.
4184 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4186 match find_best_match_for_name(
4187 names.iter().map(|suggestion| &suggestion.candidate),
4191 Some(found) if found != name => names
4193 .find(|suggestion| suggestion.candidate == found),
4198 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4199 where F: FnOnce(&mut Resolver<'_>)
4201 if let Some(label) = label {
4202 self.unused_labels.insert(id, label.ident.span);
4203 let def = Def::Label(id);
4204 self.with_label_rib(|this| {
4205 let ident = label.ident.modern_and_legacy();
4206 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4214 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4215 self.with_resolved_label(label, id, |this| this.visit_block(block));
4218 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4219 // First, record candidate traits for this expression if it could
4220 // result in the invocation of a method call.
4222 self.record_candidate_traits_for_expr_if_necessary(expr);
4224 // Next, resolve the node.
4226 ExprKind::Path(ref qself, ref path) => {
4227 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4228 visit::walk_expr(self, expr);
4231 ExprKind::Struct(ref path, ..) => {
4232 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4233 visit::walk_expr(self, expr);
4236 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4237 let def = self.search_label(label.ident, |rib, ident| {
4238 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4242 // Search again for close matches...
4243 // Picks the first label that is "close enough", which is not necessarily
4244 // the closest match
4245 let close_match = self.search_label(label.ident, |rib, ident| {
4246 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4247 find_best_match_for_name(names, &*ident.as_str(), None)
4249 self.record_def(expr.id, err_path_resolution());
4252 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4255 Some(Def::Label(id)) => {
4256 // Since this def is a label, it is never read.
4257 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4258 self.unused_labels.remove(&id);
4261 span_bug!(expr.span, "label wasn't mapped to a label def!");
4265 // visit `break` argument if any
4266 visit::walk_expr(self, expr);
4269 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4270 self.visit_expr(subexpression);
4272 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4273 let mut bindings_list = FxHashMap::default();
4275 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4277 // This has to happen *after* we determine which pat_idents are variants
4278 self.check_consistent_bindings(pats);
4279 self.visit_block(if_block);
4280 self.ribs[ValueNS].pop();
4282 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4285 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4287 ExprKind::While(ref subexpression, ref block, label) => {
4288 self.with_resolved_label(label, expr.id, |this| {
4289 this.visit_expr(subexpression);
4290 this.visit_block(block);
4294 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4295 self.with_resolved_label(label, expr.id, |this| {
4296 this.visit_expr(subexpression);
4297 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4298 let mut bindings_list = FxHashMap::default();
4300 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4302 // This has to happen *after* we determine which pat_idents are variants.
4303 this.check_consistent_bindings(pats);
4304 this.visit_block(block);
4305 this.ribs[ValueNS].pop();
4309 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4310 self.visit_expr(subexpression);
4311 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4312 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4314 self.resolve_labeled_block(label, expr.id, block);
4316 self.ribs[ValueNS].pop();
4319 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4321 // Equivalent to `visit::walk_expr` + passing some context to children.
4322 ExprKind::Field(ref subexpression, _) => {
4323 self.resolve_expr(subexpression, Some(expr));
4325 ExprKind::MethodCall(ref segment, ref arguments) => {
4326 let mut arguments = arguments.iter();
4327 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4328 for argument in arguments {
4329 self.resolve_expr(argument, None);
4331 self.visit_path_segment(expr.span, segment);
4334 ExprKind::Call(ref callee, ref arguments) => {
4335 self.resolve_expr(callee, Some(expr));
4336 for argument in arguments {
4337 self.resolve_expr(argument, None);
4340 ExprKind::Type(ref type_expr, _) => {
4341 self.current_type_ascription.push(type_expr.span);
4342 visit::walk_expr(self, expr);
4343 self.current_type_ascription.pop();
4345 // Resolve the body of async exprs inside the async closure to which they desugar
4346 ExprKind::Async(_, async_closure_id, ref block) => {
4347 let rib_kind = ClosureRibKind(async_closure_id);
4348 self.ribs[ValueNS].push(Rib::new(rib_kind));
4349 self.label_ribs.push(Rib::new(rib_kind));
4350 self.visit_block(&block);
4351 self.label_ribs.pop();
4352 self.ribs[ValueNS].pop();
4354 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4355 // resolve the arguments within the proper scopes so that usages of them inside the
4356 // closure are detected as upvars rather than normal closure arg usages.
4358 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4359 ref fn_decl, ref body, _span,
4361 let rib_kind = ClosureRibKind(expr.id);
4362 self.ribs[ValueNS].push(Rib::new(rib_kind));
4363 self.label_ribs.push(Rib::new(rib_kind));
4364 // Resolve arguments:
4365 let mut bindings_list = FxHashMap::default();
4366 for argument in &fn_decl.inputs {
4367 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4368 self.visit_ty(&argument.ty);
4370 // No need to resolve return type-- the outer closure return type is
4371 // FunctionRetTy::Default
4373 // Now resolve the inner closure
4375 let rib_kind = ClosureRibKind(inner_closure_id);
4376 self.ribs[ValueNS].push(Rib::new(rib_kind));
4377 self.label_ribs.push(Rib::new(rib_kind));
4378 // No need to resolve arguments: the inner closure has none.
4379 // Resolve the return type:
4380 visit::walk_fn_ret_ty(self, &fn_decl.output);
4382 self.visit_expr(body);
4383 self.label_ribs.pop();
4384 self.ribs[ValueNS].pop();
4386 self.label_ribs.pop();
4387 self.ribs[ValueNS].pop();
4390 visit::walk_expr(self, expr);
4395 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4397 ExprKind::Field(_, ident) => {
4398 // FIXME(#6890): Even though you can't treat a method like a
4399 // field, we need to add any trait methods we find that match
4400 // the field name so that we can do some nice error reporting
4401 // later on in typeck.
4402 let traits = self.get_traits_containing_item(ident, ValueNS);
4403 self.trait_map.insert(expr.id, traits);
4405 ExprKind::MethodCall(ref segment, ..) => {
4406 debug!("(recording candidate traits for expr) recording traits for {}",
4408 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4409 self.trait_map.insert(expr.id, traits);
4417 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4418 -> Vec<TraitCandidate> {
4419 debug!("(getting traits containing item) looking for '{}'", ident.name);
4421 let mut found_traits = Vec::new();
4422 // Look for the current trait.
4423 if let Some((module, _)) = self.current_trait_ref {
4424 if self.resolve_ident_in_module(
4425 ModuleOrUniformRoot::Module(module),
4432 let def_id = module.def_id().unwrap();
4433 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4437 ident.span = ident.span.modern();
4438 let mut search_module = self.current_module;
4440 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4441 search_module = unwrap_or!(
4442 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4446 if let Some(prelude) = self.prelude {
4447 if !search_module.no_implicit_prelude {
4448 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4455 fn get_traits_in_module_containing_item(&mut self,
4459 found_traits: &mut Vec<TraitCandidate>) {
4460 assert!(ns == TypeNS || ns == ValueNS);
4461 let mut traits = module.traits.borrow_mut();
4462 if traits.is_none() {
4463 let mut collected_traits = Vec::new();
4464 module.for_each_child(|name, ns, binding| {
4465 if ns != TypeNS { return }
4466 match binding.def() {
4468 Def::TraitAlias(_) => collected_traits.push((name, binding)),
4472 *traits = Some(collected_traits.into_boxed_slice());
4475 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4476 // Traits have pseudo-modules that can be used to search for the given ident.
4477 if let Some(module) = binding.module() {
4478 let mut ident = ident;
4479 if ident.span.glob_adjust(
4481 binding.span.ctxt().modern(),
4485 if self.resolve_ident_in_module_unadjusted(
4486 ModuleOrUniformRoot::Module(module),
4492 let import_id = match binding.kind {
4493 NameBindingKind::Import { directive, .. } => {
4494 self.maybe_unused_trait_imports.insert(directive.id);
4495 self.add_to_glob_map(&directive, trait_name);
4500 let trait_def_id = module.def_id().unwrap();
4501 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id });
4503 } else if let Def::TraitAlias(_) = binding.def() {
4504 // For now, just treat all trait aliases as possible candidates, since we don't
4505 // know if the ident is somewhere in the transitive bounds.
4507 let import_id = match binding.kind {
4508 NameBindingKind::Import { directive, .. } => {
4509 self.maybe_unused_trait_imports.insert(directive.id);
4510 self.add_to_glob_map(&directive, trait_name);
4515 let trait_def_id = binding.def().def_id();
4516 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id });
4518 bug!("candidate is not trait or trait alias?")
4523 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4524 lookup_ident: Ident,
4525 namespace: Namespace,
4526 start_module: &'a ModuleData<'a>,
4528 filter_fn: FilterFn)
4529 -> Vec<ImportSuggestion>
4530 where FilterFn: Fn(Def) -> bool
4532 let mut candidates = Vec::new();
4533 let mut seen_modules = FxHashSet::default();
4534 let not_local_module = crate_name != keywords::Crate.ident();
4535 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4537 while let Some((in_module,
4539 in_module_is_extern)) = worklist.pop() {
4540 self.populate_module_if_necessary(in_module);
4542 // We have to visit module children in deterministic order to avoid
4543 // instabilities in reported imports (#43552).
4544 in_module.for_each_child_stable(|ident, ns, name_binding| {
4545 // avoid imports entirely
4546 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4547 // avoid non-importable candidates as well
4548 if !name_binding.is_importable() { return; }
4550 // collect results based on the filter function
4551 if ident.name == lookup_ident.name && ns == namespace {
4552 let def = name_binding.def();
4555 let mut segms = path_segments.clone();
4556 if lookup_ident.span.rust_2018() {
4557 // crate-local absolute paths start with `crate::` in edition 2018
4558 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4560 0, ast::PathSegment::from_ident(crate_name)
4564 segms.push(ast::PathSegment::from_ident(ident));
4566 span: name_binding.span,
4569 // the entity is accessible in the following cases:
4570 // 1. if it's defined in the same crate, it's always
4571 // accessible (since private entities can be made public)
4572 // 2. if it's defined in another crate, it's accessible
4573 // only if both the module is public and the entity is
4574 // declared as public (due to pruning, we don't explore
4575 // outside crate private modules => no need to check this)
4576 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4577 let did = match def {
4578 Def::Ctor(did, ..) => self.parent(did),
4579 _ => def.opt_def_id(),
4581 candidates.push(ImportSuggestion { did, path });
4586 // collect submodules to explore
4587 if let Some(module) = name_binding.module() {
4589 let mut path_segments = path_segments.clone();
4590 path_segments.push(ast::PathSegment::from_ident(ident));
4592 let is_extern_crate_that_also_appears_in_prelude =
4593 name_binding.is_extern_crate() &&
4594 lookup_ident.span.rust_2018();
4596 let is_visible_to_user =
4597 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4599 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4600 // add the module to the lookup
4601 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4602 if seen_modules.insert(module.def_id().unwrap()) {
4603 worklist.push((module, path_segments, is_extern));
4613 /// When name resolution fails, this method can be used to look up candidate
4614 /// entities with the expected name. It allows filtering them using the
4615 /// supplied predicate (which should be used to only accept the types of
4616 /// definitions expected, e.g., traits). The lookup spans across all crates.
4618 /// N.B., the method does not look into imports, but this is not a problem,
4619 /// since we report the definitions (thus, the de-aliased imports).
4620 fn lookup_import_candidates<FilterFn>(&mut self,
4621 lookup_ident: Ident,
4622 namespace: Namespace,
4623 filter_fn: FilterFn)
4624 -> Vec<ImportSuggestion>
4625 where FilterFn: Fn(Def) -> bool
4627 let mut suggestions = self.lookup_import_candidates_from_module(
4628 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4630 if lookup_ident.span.rust_2018() {
4631 let extern_prelude_names = self.extern_prelude.clone();
4632 for (ident, _) in extern_prelude_names.into_iter() {
4633 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4635 let crate_root = self.get_module(DefId {
4637 index: CRATE_DEF_INDEX,
4639 self.populate_module_if_necessary(&crate_root);
4641 suggestions.extend(self.lookup_import_candidates_from_module(
4642 lookup_ident, namespace, crate_root, ident, &filter_fn));
4650 fn find_module(&mut self,
4652 -> Option<(Module<'a>, ImportSuggestion)>
4654 let mut result = None;
4655 let mut seen_modules = FxHashSet::default();
4656 let mut worklist = vec![(self.graph_root, Vec::new())];
4658 while let Some((in_module, path_segments)) = worklist.pop() {
4659 // abort if the module is already found
4660 if result.is_some() { break; }
4662 self.populate_module_if_necessary(in_module);
4664 in_module.for_each_child_stable(|ident, _, name_binding| {
4665 // abort if the module is already found or if name_binding is private external
4666 if result.is_some() || !name_binding.vis.is_visible_locally() {
4669 if let Some(module) = name_binding.module() {
4671 let mut path_segments = path_segments.clone();
4672 path_segments.push(ast::PathSegment::from_ident(ident));
4673 if module.def() == Some(module_def) {
4675 span: name_binding.span,
4676 segments: path_segments,
4678 let did = module.def().and_then(|def| def.opt_def_id());
4679 result = Some((module, ImportSuggestion { did, path }));
4681 // add the module to the lookup
4682 if seen_modules.insert(module.def_id().unwrap()) {
4683 worklist.push((module, path_segments));
4693 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4694 if let Def::Enum(..) = enum_def {} else {
4695 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4698 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4699 self.populate_module_if_necessary(enum_module);
4701 let mut variants = Vec::new();
4702 enum_module.for_each_child_stable(|ident, _, name_binding| {
4703 if let Def::Variant(..) = name_binding.def() {
4704 let mut segms = enum_import_suggestion.path.segments.clone();
4705 segms.push(ast::PathSegment::from_ident(ident));
4706 variants.push(Path {
4707 span: name_binding.span,
4716 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4717 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4718 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4719 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4723 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4725 ast::VisibilityKind::Public => ty::Visibility::Public,
4726 ast::VisibilityKind::Crate(..) => {
4727 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4729 ast::VisibilityKind::Inherited => {
4730 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4732 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4733 // For visibilities we are not ready to provide correct implementation of "uniform
4734 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4735 // On 2015 edition visibilities are resolved as crate-relative by default,
4736 // so we are prepending a root segment if necessary.
4737 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4738 let crate_root = if ident.is_path_segment_keyword() {
4740 } else if ident.span.rust_2018() {
4741 let msg = "relative paths are not supported in visibilities on 2018 edition";
4742 self.session.struct_span_err(ident.span, msg)
4746 format!("crate::{}", path),
4747 Applicability::MaybeIncorrect,
4750 return ty::Visibility::Public;
4752 let ctxt = ident.span.ctxt();
4753 Some(Segment::from_ident(Ident::new(
4754 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4758 let segments = crate_root.into_iter()
4759 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4760 let def = self.smart_resolve_path_fragment(
4765 PathSource::Visibility,
4766 CrateLint::SimplePath(id),
4768 if def == Def::Err {
4769 ty::Visibility::Public
4771 let vis = ty::Visibility::Restricted(def.def_id());
4772 if self.is_accessible(vis) {
4775 self.session.span_err(path.span, "visibilities can only be restricted \
4776 to ancestor modules");
4777 ty::Visibility::Public
4784 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4785 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4788 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4789 vis.is_accessible_from(module.normal_ancestor_id, self)
4792 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4793 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4794 if !ptr::eq(module, old_module) {
4795 span_bug!(binding.span, "parent module is reset for binding");
4800 fn disambiguate_legacy_vs_modern(
4802 legacy: &'a NameBinding<'a>,
4803 modern: &'a NameBinding<'a>,
4805 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4806 // is disambiguated to mitigate regressions from macro modularization.
4807 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4808 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4809 self.binding_parent_modules.get(&PtrKey(modern))) {
4810 (Some(legacy), Some(modern)) =>
4811 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4812 modern.is_ancestor_of(legacy),
4817 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4818 if b.span.is_dummy() {
4819 let add_built_in = match b.def() {
4820 // These already contain the "built-in" prefix or look bad with it.
4821 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4824 let (built_in, from) = if from_prelude {
4825 ("", " from prelude")
4826 } else if b.is_extern_crate() && !b.is_import() &&
4827 self.session.opts.externs.get(&ident.as_str()).is_some() {
4828 ("", " passed with `--extern`")
4829 } else if add_built_in {
4835 let article = if built_in.is_empty() { b.article() } else { "a" };
4836 format!("{a}{built_in} {thing}{from}",
4837 a = article, thing = b.descr(), built_in = built_in, from = from)
4839 let introduced = if b.is_import() { "imported" } else { "defined" };
4840 format!("the {thing} {introduced} here",
4841 thing = b.descr(), introduced = introduced)
4845 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4846 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4847 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4848 // We have to print the span-less alternative first, otherwise formatting looks bad.
4849 (b2, b1, misc2, misc1, true)
4851 (b1, b2, misc1, misc2, false)
4854 let mut err = struct_span_err!(self.session, ident.span, E0659,
4855 "`{ident}` is ambiguous ({why})",
4856 ident = ident, why = kind.descr());
4857 err.span_label(ident.span, "ambiguous name");
4859 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4860 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4861 let note_msg = format!("`{ident}` could{also} refer to {what}",
4862 ident = ident, also = also, what = what);
4864 let mut help_msgs = Vec::new();
4865 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4866 kind == AmbiguityKind::GlobVsExpanded ||
4867 kind == AmbiguityKind::GlobVsOuter &&
4868 swapped != also.is_empty()) {
4869 help_msgs.push(format!("consider adding an explicit import of \
4870 `{ident}` to disambiguate", ident = ident))
4872 if b.is_extern_crate() && ident.span.rust_2018() {
4873 help_msgs.push(format!(
4874 "use `::{ident}` to refer to this {thing} unambiguously",
4875 ident = ident, thing = b.descr(),
4878 if misc == AmbiguityErrorMisc::SuggestCrate {
4879 help_msgs.push(format!(
4880 "use `crate::{ident}` to refer to this {thing} unambiguously",
4881 ident = ident, thing = b.descr(),
4883 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4884 help_msgs.push(format!(
4885 "use `self::{ident}` to refer to this {thing} unambiguously",
4886 ident = ident, thing = b.descr(),
4890 err.span_note(b.span, ¬e_msg);
4891 for (i, help_msg) in help_msgs.iter().enumerate() {
4892 let or = if i == 0 { "" } else { "or " };
4893 err.help(&format!("{}{}", or, help_msg));
4897 could_refer_to(b1, misc1, "");
4898 could_refer_to(b2, misc2, " also");
4902 fn report_errors(&mut self, krate: &Crate) {
4903 self.report_with_use_injections(krate);
4905 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4906 let msg = "macro-expanded `macro_export` macros from the current crate \
4907 cannot be referred to by absolute paths";
4908 self.session.buffer_lint_with_diagnostic(
4909 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4910 CRATE_NODE_ID, span_use, msg,
4911 lint::builtin::BuiltinLintDiagnostics::
4912 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4916 for ambiguity_error in &self.ambiguity_errors {
4917 self.report_ambiguity_error(ambiguity_error);
4920 let mut reported_spans = FxHashSet::default();
4921 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4922 if reported_spans.insert(dedup_span) {
4923 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4924 binding.descr(), ident.name);
4929 fn report_with_use_injections(&mut self, krate: &Crate) {
4930 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4931 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4932 if !candidates.is_empty() {
4933 show_candidates(&mut err, span, &candidates, better, found_use);
4939 fn report_conflict<'b>(&mut self,
4943 new_binding: &NameBinding<'b>,
4944 old_binding: &NameBinding<'b>) {
4945 // Error on the second of two conflicting names
4946 if old_binding.span.lo() > new_binding.span.lo() {
4947 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4950 let container = match parent.kind {
4951 ModuleKind::Def(Def::Mod(_), _) => "module",
4952 ModuleKind::Def(Def::Trait(_), _) => "trait",
4953 ModuleKind::Block(..) => "block",
4957 let old_noun = match old_binding.is_import() {
4959 false => "definition",
4962 let new_participle = match new_binding.is_import() {
4967 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4969 if let Some(s) = self.name_already_seen.get(&name) {
4975 let old_kind = match (ns, old_binding.module()) {
4976 (ValueNS, _) => "value",
4977 (MacroNS, _) => "macro",
4978 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4979 (TypeNS, Some(module)) if module.is_normal() => "module",
4980 (TypeNS, Some(module)) if module.is_trait() => "trait",
4981 (TypeNS, _) => "type",
4984 let msg = format!("the name `{}` is defined multiple times", name);
4986 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4987 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4988 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4989 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4990 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4992 _ => match (old_binding.is_import(), new_binding.is_import()) {
4993 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4994 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4995 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4999 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5004 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5006 self.session.source_map().def_span(old_binding.span),
5007 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5010 // See https://github.com/rust-lang/rust/issues/32354
5011 use NameBindingKind::Import;
5012 let directive = match (&new_binding.kind, &old_binding.kind) {
5013 // If there are two imports where one or both have attributes then prefer removing the
5014 // import without attributes.
5015 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5016 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5017 (new.has_attributes || old.has_attributes)
5019 if old.has_attributes {
5020 Some((new, new_binding.span, true))
5022 Some((old, old_binding.span, true))
5025 // Otherwise prioritize the new binding.
5026 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5027 Some((directive, new_binding.span, other.is_import())),
5028 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5029 Some((directive, old_binding.span, other.is_import())),
5033 // Check if the target of the use for both bindings is the same.
5034 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5035 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5036 let from_item = self.extern_prelude.get(&ident)
5037 .map(|entry| entry.introduced_by_item)
5039 // Only suggest removing an import if both bindings are to the same def, if both spans
5040 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5041 // been introduced by a item.
5042 let should_remove_import = duplicate && !has_dummy_span &&
5043 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5046 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5047 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5048 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5049 // Simple case - remove the entire import. Due to the above match arm, this can
5050 // only be a single use so just remove it entirely.
5051 err.tool_only_span_suggestion(
5052 directive.use_span_with_attributes,
5053 "remove unnecessary import",
5055 Applicability::MaybeIncorrect,
5058 Some((directive, span, _)) =>
5059 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5064 self.name_already_seen.insert(name, span);
5067 /// This function adds a suggestion to change the binding name of a new import that conflicts
5068 /// with an existing import.
5070 /// ```ignore (diagnostic)
5071 /// help: you can use `as` to change the binding name of the import
5073 /// LL | use foo::bar as other_bar;
5074 /// | ^^^^^^^^^^^^^^^^^^^^^
5076 fn add_suggestion_for_rename_of_use(
5078 err: &mut DiagnosticBuilder<'_>,
5080 directive: &ImportDirective<'_>,
5083 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5084 format!("Other{}", name)
5086 format!("other_{}", name)
5089 let mut suggestion = None;
5090 match directive.subclass {
5091 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5092 suggestion = Some(format!("self as {}", suggested_name)),
5093 ImportDirectiveSubclass::SingleImport { source, .. } => {
5094 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5095 .map(|pos| pos as usize) {
5096 if let Ok(snippet) = self.session.source_map()
5097 .span_to_snippet(binding_span) {
5098 if pos <= snippet.len() {
5099 suggestion = Some(format!(
5103 if snippet.ends_with(";") { ";" } else { "" }
5109 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5110 suggestion = Some(format!(
5111 "extern crate {} as {};",
5112 source.unwrap_or(target.name),
5115 _ => unreachable!(),
5118 let rename_msg = "you can use `as` to change the binding name of the import";
5119 if let Some(suggestion) = suggestion {
5120 err.span_suggestion(
5124 Applicability::MaybeIncorrect,
5127 err.span_label(binding_span, rename_msg);
5131 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5132 /// nested. In the following example, this function will be invoked to remove the `a` binding
5133 /// in the second use statement:
5135 /// ```ignore (diagnostic)
5136 /// use issue_52891::a;
5137 /// use issue_52891::{d, a, e};
5140 /// The following suggestion will be added:
5142 /// ```ignore (diagnostic)
5143 /// use issue_52891::{d, a, e};
5144 /// ^-- help: remove unnecessary import
5147 /// If the nested use contains only one import then the suggestion will remove the entire
5150 /// It is expected that the directive provided is a nested import - this isn't checked by the
5151 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5152 /// as characters expected by span manipulations won't be present.
5153 fn add_suggestion_for_duplicate_nested_use(
5155 err: &mut DiagnosticBuilder<'_>,
5156 directive: &ImportDirective<'_>,
5159 assert!(directive.is_nested());
5160 let message = "remove unnecessary import";
5162 // Two examples will be used to illustrate the span manipulations we're doing:
5164 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5165 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5166 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5167 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5169 let (found_closing_brace, span) = find_span_of_binding_until_next_binding(
5170 self.session, binding_span, directive.use_span,
5173 // If there was a closing brace then identify the span to remove any trailing commas from
5174 // previous imports.
5175 if found_closing_brace {
5176 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
5177 err.tool_only_span_suggestion(span, message, String::new(),
5178 Applicability::MaybeIncorrect);
5180 // Remove the entire line if we cannot extend the span back, this indicates a
5181 // `issue_52891::{self}` case.
5182 err.span_suggestion(directive.use_span_with_attributes, message, String::new(),
5183 Applicability::MaybeIncorrect);
5189 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5192 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5193 -> Option<&'a NameBinding<'a>> {
5194 if ident.is_path_segment_keyword() {
5195 // Make sure `self`, `super` etc produce an error when passed to here.
5198 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5199 if let Some(binding) = entry.extern_crate_item {
5200 if !speculative && entry.introduced_by_item {
5201 self.record_use(ident, TypeNS, binding, false);
5205 let crate_id = if !speculative {
5206 self.crate_loader.process_path_extern(ident.name, ident.span)
5207 } else if let Some(crate_id) =
5208 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5213 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5214 self.populate_module_if_necessary(&crate_root);
5215 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5216 .to_name_binding(self.arenas))
5222 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5223 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5226 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5227 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5230 fn names_to_string(idents: &[Ident]) -> String {
5231 let mut result = String::new();
5232 for (i, ident) in idents.iter()
5233 .filter(|ident| ident.name != keywords::PathRoot.name())
5236 result.push_str("::");
5238 result.push_str(&ident.as_str());
5243 fn path_names_to_string(path: &Path) -> String {
5244 names_to_string(&path.segments.iter()
5245 .map(|seg| seg.ident)
5246 .collect::<Vec<_>>())
5249 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5250 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5251 let variant_path = &suggestion.path;
5252 let variant_path_string = path_names_to_string(variant_path);
5254 let path_len = suggestion.path.segments.len();
5255 let enum_path = ast::Path {
5256 span: suggestion.path.span,
5257 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5259 let enum_path_string = path_names_to_string(&enum_path);
5261 (variant_path_string, enum_path_string)
5264 /// When an entity with a given name is not available in scope, we search for
5265 /// entities with that name in all crates. This method allows outputting the
5266 /// results of this search in a programmer-friendly way
5267 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5268 // This is `None` if all placement locations are inside expansions
5270 candidates: &[ImportSuggestion],
5274 // we want consistent results across executions, but candidates are produced
5275 // by iterating through a hash map, so make sure they are ordered:
5276 let mut path_strings: Vec<_> =
5277 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5278 path_strings.sort();
5280 let better = if better { "better " } else { "" };
5281 let msg_diff = match path_strings.len() {
5282 1 => " is found in another module, you can import it",
5283 _ => "s are found in other modules, you can import them",
5285 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5287 if let Some(span) = span {
5288 for candidate in &mut path_strings {
5289 // produce an additional newline to separate the new use statement
5290 // from the directly following item.
5291 let additional_newline = if found_use {
5296 *candidate = format!("use {};\n{}", candidate, additional_newline);
5299 err.span_suggestions(
5302 path_strings.into_iter(),
5303 Applicability::Unspecified,
5308 for candidate in path_strings {
5310 msg.push_str(&candidate);
5315 /// A somewhat inefficient routine to obtain the name of a module.
5316 fn module_to_string(module: Module<'_>) -> Option<String> {
5317 let mut names = Vec::new();
5319 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5320 if let ModuleKind::Def(_, name) = module.kind {
5321 if let Some(parent) = module.parent {
5322 names.push(Ident::with_empty_ctxt(name));
5323 collect_mod(names, parent);
5326 // danger, shouldn't be ident?
5327 names.push(Ident::from_str("<opaque>"));
5328 collect_mod(names, module.parent.unwrap());
5331 collect_mod(&mut names, module);
5333 if names.is_empty() {
5336 Some(names_to_string(&names.into_iter()
5338 .collect::<Vec<_>>()))
5341 fn err_path_resolution() -> PathResolution {
5342 PathResolution::new(Def::Err)
5345 #[derive(Copy, Clone, Debug)]
5347 /// Do not issue the lint.
5350 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5351 /// In this case, we can take the span of that path.
5354 /// This lint comes from a `use` statement. In this case, what we
5355 /// care about really is the *root* `use` statement; e.g., if we
5356 /// have nested things like `use a::{b, c}`, we care about the
5358 UsePath { root_id: NodeId, root_span: Span },
5360 /// This is the "trait item" from a fully qualified path. For example,
5361 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5362 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5363 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5367 fn node_id(&self) -> Option<NodeId> {
5369 CrateLint::No => None,
5370 CrateLint::SimplePath(id) |
5371 CrateLint::UsePath { root_id: id, .. } |
5372 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5377 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }