1 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
3 #![feature(crate_visibility_modifier)]
4 #![feature(label_break_value)]
6 #![feature(rustc_diagnostic_macros)]
8 #![recursion_limit="256"]
10 #![deny(rust_2018_idioms)]
12 pub use rustc::hir::def::{Namespace, PerNS};
14 use GenericParameters::*;
17 use rustc::hir::map::{Definitions, DefCollector};
18 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
19 use rustc::middle::cstore::CrateStore;
20 use rustc::session::Session;
22 use rustc::hir::def::*;
23 use rustc::hir::def::Namespace::*;
24 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
25 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
26 use rustc::ty::{self, DefIdTree};
27 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
28 use rustc::{bug, span_bug};
30 use rustc_metadata::creader::CrateLoader;
31 use rustc_metadata::cstore::CStore;
33 use syntax::source_map::SourceMap;
34 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
35 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
36 use syntax::ext::base::SyntaxExtension;
37 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
38 use syntax::ext::base::MacroKind;
39 use syntax::symbol::{Symbol, keywords};
40 use syntax::util::lev_distance::find_best_match_for_name;
42 use syntax::visit::{self, FnKind, Visitor};
44 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
45 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
46 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
47 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
48 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
50 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
52 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
53 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
57 use std::cell::{Cell, RefCell};
58 use std::{cmp, fmt, iter, mem, ptr};
59 use std::collections::BTreeSet;
60 use std::mem::replace;
61 use rustc_data_structures::ptr_key::PtrKey;
62 use rustc_data_structures::sync::Lrc;
64 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
65 use macros::{InvocationData, LegacyBinding, ParentScope};
67 // N.B., this module needs to be declared first so diagnostics are
68 // registered before they are used.
73 mod build_reduced_graph;
76 fn is_known_tool(name: Name) -> bool {
77 ["clippy", "rustfmt"].contains(&&*name.as_str())
87 AbsolutePath(Namespace),
92 /// A free importable items suggested in case of resolution failure.
93 struct ImportSuggestion {
98 /// A field or associated item from self type suggested in case of resolution failure.
99 enum AssocSuggestion {
106 struct BindingError {
108 origin: BTreeSet<Span>,
109 target: BTreeSet<Span>,
112 struct TypoSuggestion {
115 /// The kind of the binding ("crate", "module", etc.)
118 /// An appropriate article to refer to the binding ("a", "an", etc.)
119 article: &'static str,
122 impl PartialOrd for BindingError {
123 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
124 Some(self.cmp(other))
128 impl PartialEq for BindingError {
129 fn eq(&self, other: &BindingError) -> bool {
130 self.name == other.name
134 impl Ord for BindingError {
135 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
136 self.name.cmp(&other.name)
140 enum ResolutionError<'a> {
141 /// Error E0401: can't use type or const parameters from outer function.
142 GenericParamsFromOuterFunction(Def),
143 /// Error E0403: the name is already used for a type or const parameter in this generic
145 NameAlreadyUsedInParameterList(Name, &'a Span),
146 /// Error E0407: method is not a member of trait.
147 MethodNotMemberOfTrait(Name, &'a str),
148 /// Error E0437: type is not a member of trait.
149 TypeNotMemberOfTrait(Name, &'a str),
150 /// Error E0438: const is not a member of trait.
151 ConstNotMemberOfTrait(Name, &'a str),
152 /// Error E0408: variable `{}` is not bound in all patterns.
153 VariableNotBoundInPattern(&'a BindingError),
154 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
155 VariableBoundWithDifferentMode(Name, Span),
156 /// Error E0415: identifier is bound more than once in this parameter list.
157 IdentifierBoundMoreThanOnceInParameterList(&'a str),
158 /// Error E0416: identifier is bound more than once in the same pattern.
159 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
160 /// Error E0426: use of undeclared label.
161 UndeclaredLabel(&'a str, Option<Name>),
162 /// Error E0429: `self` imports are only allowed within a `{ }` list.
163 SelfImportsOnlyAllowedWithin,
164 /// Error E0430: `self` import can only appear once in the list.
165 SelfImportCanOnlyAppearOnceInTheList,
166 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
167 SelfImportOnlyInImportListWithNonEmptyPrefix,
168 /// Error E0433: failed to resolve.
169 FailedToResolve(&'a str),
170 /// Error E0434: can't capture dynamic environment in a fn item.
171 CannotCaptureDynamicEnvironmentInFnItem,
172 /// Error E0435: attempt to use a non-constant value in a constant.
173 AttemptToUseNonConstantValueInConstant,
174 /// Error E0530: `X` bindings cannot shadow `Y`s.
175 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
176 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
177 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
180 /// Combines an error with provided span and emits it.
182 /// This takes the error provided, combines it with the span and any additional spans inside the
183 /// error and emits it.
184 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
186 resolution_error: ResolutionError<'a>) {
187 resolve_struct_error(resolver, span, resolution_error).emit();
190 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
192 resolution_error: ResolutionError<'a>)
193 -> DiagnosticBuilder<'sess> {
194 match resolution_error {
195 ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
196 let mut err = struct_span_err!(resolver.session,
199 "can't use generic parameters from outer function",
201 err.span_label(span, format!("use of generic parameter from outer function"));
203 let cm = resolver.session.source_map();
205 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
206 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
207 resolver.definitions.opt_span(def_id)
210 reduce_impl_span_to_impl_keyword(cm, impl_span),
211 "`Self` type implicitly declared here, by this `impl`",
214 match (maybe_trait_defid, maybe_impl_defid) {
216 err.span_label(span, "can't use `Self` here");
219 err.span_label(span, "use a type here instead");
221 (None, None) => bug!("`impl` without trait nor type?"),
225 Def::TyParam(def_id) => {
226 if let Some(span) = resolver.definitions.opt_span(def_id) {
227 err.span_label(span, "type variable from outer function");
230 Def::ConstParam(def_id) => {
231 if let Some(span) = resolver.definitions.opt_span(def_id) {
232 err.span_label(span, "const variable from outer function");
236 bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
241 // Try to retrieve the span of the function signature and generate a new message with
242 // a local type or const parameter.
243 let sugg_msg = &format!("try using a local generic parameter instead");
244 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
245 // Suggest the modification to the user
250 Applicability::MachineApplicable,
252 } else if let Some(sp) = cm.generate_fn_name_span(span) {
254 format!("try adding a local generic parameter in this method instead"));
256 err.help(&format!("try using a local generic parameter instead"));
261 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
262 let mut err = struct_span_err!(resolver.session,
265 "the name `{}` is already used for a generic \
266 parameter in this list of generic parameters",
268 err.span_label(span, "already used");
269 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
272 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
273 let mut err = struct_span_err!(resolver.session,
276 "method `{}` is not a member of trait `{}`",
279 err.span_label(span, format!("not a member of trait `{}`", trait_));
282 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
283 let mut err = struct_span_err!(resolver.session,
286 "type `{}` is not a member of trait `{}`",
289 err.span_label(span, format!("not a member of trait `{}`", trait_));
292 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
293 let mut err = struct_span_err!(resolver.session,
296 "const `{}` is not a member of trait `{}`",
299 err.span_label(span, format!("not a member of trait `{}`", trait_));
302 ResolutionError::VariableNotBoundInPattern(binding_error) => {
303 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
304 let msp = MultiSpan::from_spans(target_sp.clone());
305 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
306 let mut err = resolver.session.struct_span_err_with_code(
309 DiagnosticId::Error("E0408".into()),
311 for sp in target_sp {
312 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
314 let origin_sp = binding_error.origin.iter().cloned();
315 for sp in origin_sp {
316 err.span_label(sp, "variable not in all patterns");
320 ResolutionError::VariableBoundWithDifferentMode(variable_name,
321 first_binding_span) => {
322 let mut err = struct_span_err!(resolver.session,
325 "variable `{}` is bound in inconsistent \
326 ways within the same match arm",
328 err.span_label(span, "bound in different ways");
329 err.span_label(first_binding_span, "first binding");
332 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
333 let mut err = struct_span_err!(resolver.session,
336 "identifier `{}` is bound more than once in this parameter list",
338 err.span_label(span, "used as parameter more than once");
341 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
342 let mut err = struct_span_err!(resolver.session,
345 "identifier `{}` is bound more than once in the same pattern",
347 err.span_label(span, "used in a pattern more than once");
350 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
351 let mut err = struct_span_err!(resolver.session,
354 "use of undeclared label `{}`",
356 if let Some(lev_candidate) = lev_candidate {
357 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
359 err.span_label(span, format!("undeclared label `{}`", name));
363 ResolutionError::SelfImportsOnlyAllowedWithin => {
364 struct_span_err!(resolver.session,
368 "`self` imports are only allowed within a { } list")
370 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
371 let mut err = struct_span_err!(resolver.session, span, E0430,
372 "`self` import can only appear once in an import list");
373 err.span_label(span, "can only appear once in an import list");
376 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
377 let mut err = struct_span_err!(resolver.session, span, E0431,
378 "`self` import can only appear in an import list with \
379 a non-empty prefix");
380 err.span_label(span, "can only appear in an import list with a non-empty prefix");
383 ResolutionError::FailedToResolve(msg) => {
384 let mut err = struct_span_err!(resolver.session, span, E0433,
385 "failed to resolve: {}", msg);
386 err.span_label(span, msg);
389 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
390 let mut err = struct_span_err!(resolver.session,
394 "can't capture dynamic environment in a fn item");
395 err.help("use the `|| { ... }` closure form instead");
398 ResolutionError::AttemptToUseNonConstantValueInConstant => {
399 let mut err = struct_span_err!(resolver.session, span, E0435,
400 "attempt to use a non-constant value in a constant");
401 err.span_label(span, "non-constant value");
404 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
405 let shadows_what = binding.descr();
406 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
407 what_binding, shadows_what);
408 err.span_label(span, format!("cannot be named the same as {} {}",
409 binding.article(), shadows_what));
410 let participle = if binding.is_import() { "imported" } else { "defined" };
411 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
412 err.span_label(binding.span, msg);
415 ResolutionError::ForwardDeclaredTyParam => {
416 let mut err = struct_span_err!(resolver.session, span, E0128,
417 "type parameters with a default cannot use \
418 forward declared identifiers");
420 span, "defaulted type parameters cannot be forward declared".to_string());
426 /// Adjust the impl span so that just the `impl` keyword is taken by removing
427 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
428 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
430 /// *Attention*: the method used is very fragile since it essentially duplicates the work of the
431 /// parser. If you need to use this function or something similar, please consider updating the
432 /// `source_map` functions and this function to something more robust.
433 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
434 let impl_span = cm.span_until_char(impl_span, '<');
435 let impl_span = cm.span_until_whitespace(impl_span);
439 #[derive(Copy, Clone, Debug)]
442 binding_mode: BindingMode,
445 /// Map from the name in a pattern to its binding mode.
446 type BindingMap = FxHashMap<Ident, BindingInfo>;
448 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
459 fn descr(self) -> &'static str {
461 PatternSource::Match => "match binding",
462 PatternSource::IfLet => "if let binding",
463 PatternSource::WhileLet => "while let binding",
464 PatternSource::Let => "let binding",
465 PatternSource::For => "for binding",
466 PatternSource::FnParam => "function parameter",
471 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
472 enum AliasPossibility {
477 #[derive(Copy, Clone, Debug)]
478 enum PathSource<'a> {
479 // Type paths `Path`.
481 // Trait paths in bounds or impls.
482 Trait(AliasPossibility),
483 // Expression paths `path`, with optional parent context.
484 Expr(Option<&'a Expr>),
485 // Paths in path patterns `Path`.
487 // Paths in struct expressions and patterns `Path { .. }`.
489 // Paths in tuple struct patterns `Path(..)`.
491 // `m::A::B` in `<T as m::A>::B::C`.
492 TraitItem(Namespace),
493 // Path in `pub(path)`
497 impl<'a> PathSource<'a> {
498 fn namespace(self) -> Namespace {
500 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
501 PathSource::Visibility => TypeNS,
502 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
503 PathSource::TraitItem(ns) => ns,
507 fn global_by_default(self) -> bool {
509 PathSource::Visibility => true,
510 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
511 PathSource::Struct | PathSource::TupleStruct |
512 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
516 fn defer_to_typeck(self) -> bool {
518 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
519 PathSource::Struct | PathSource::TupleStruct => true,
520 PathSource::Trait(_) | PathSource::TraitItem(..) |
521 PathSource::Visibility => false,
525 fn descr_expected(self) -> &'static str {
527 PathSource::Type => "type",
528 PathSource::Trait(_) => "trait",
529 PathSource::Pat => "unit struct/variant or constant",
530 PathSource::Struct => "struct, variant or union type",
531 PathSource::TupleStruct => "tuple struct/variant",
532 PathSource::Visibility => "module",
533 PathSource::TraitItem(ns) => match ns {
534 TypeNS => "associated type",
535 ValueNS => "method or associated constant",
536 MacroNS => bug!("associated macro"),
538 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
539 // "function" here means "anything callable" rather than `Def::Fn`,
540 // this is not precise but usually more helpful than just "value".
541 Some(&ExprKind::Call(..)) => "function",
547 fn is_expected(self, def: Def) -> bool {
549 PathSource::Type => match def {
550 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
551 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
552 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
553 Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
556 PathSource::Trait(AliasPossibility::No) => match def {
557 Def::Trait(..) => true,
560 PathSource::Trait(AliasPossibility::Maybe) => match def {
561 Def::Trait(..) => true,
562 Def::TraitAlias(..) => true,
565 PathSource::Expr(..) => match def {
566 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
567 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
568 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
569 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
570 Def::SelfCtor(..) | Def::ConstParam(..) => true,
573 PathSource::Pat => match def {
574 Def::StructCtor(_, CtorKind::Const) |
575 Def::VariantCtor(_, CtorKind::Const) |
576 Def::Const(..) | Def::AssociatedConst(..) |
577 Def::SelfCtor(..) => true,
580 PathSource::TupleStruct => match def {
581 Def::StructCtor(_, CtorKind::Fn) |
582 Def::VariantCtor(_, CtorKind::Fn) |
583 Def::SelfCtor(..) => true,
586 PathSource::Struct => match def {
587 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
588 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
591 PathSource::TraitItem(ns) => match def {
592 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
593 Def::AssociatedTy(..) if ns == TypeNS => true,
596 PathSource::Visibility => match def {
597 Def::Mod(..) => true,
603 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
604 __diagnostic_used!(E0404);
605 __diagnostic_used!(E0405);
606 __diagnostic_used!(E0412);
607 __diagnostic_used!(E0422);
608 __diagnostic_used!(E0423);
609 __diagnostic_used!(E0425);
610 __diagnostic_used!(E0531);
611 __diagnostic_used!(E0532);
612 __diagnostic_used!(E0573);
613 __diagnostic_used!(E0574);
614 __diagnostic_used!(E0575);
615 __diagnostic_used!(E0576);
616 __diagnostic_used!(E0577);
617 __diagnostic_used!(E0578);
618 match (self, has_unexpected_resolution) {
619 (PathSource::Trait(_), true) => "E0404",
620 (PathSource::Trait(_), false) => "E0405",
621 (PathSource::Type, true) => "E0573",
622 (PathSource::Type, false) => "E0412",
623 (PathSource::Struct, true) => "E0574",
624 (PathSource::Struct, false) => "E0422",
625 (PathSource::Expr(..), true) => "E0423",
626 (PathSource::Expr(..), false) => "E0425",
627 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
628 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
629 (PathSource::TraitItem(..), true) => "E0575",
630 (PathSource::TraitItem(..), false) => "E0576",
631 (PathSource::Visibility, true) => "E0577",
632 (PathSource::Visibility, false) => "E0578",
637 // A minimal representation of a path segment. We use this in resolve because
638 // we synthesize 'path segments' which don't have the rest of an AST or HIR
640 #[derive(Clone, Copy, Debug)]
647 fn from_path(path: &Path) -> Vec<Segment> {
648 path.segments.iter().map(|s| s.into()).collect()
651 fn from_ident(ident: Ident) -> Segment {
658 fn names_to_string(segments: &[Segment]) -> String {
659 names_to_string(&segments.iter()
660 .map(|seg| seg.ident)
661 .collect::<Vec<_>>())
665 impl<'a> From<&'a ast::PathSegment> for Segment {
666 fn from(seg: &'a ast::PathSegment) -> Segment {
674 struct UsePlacementFinder {
675 target_module: NodeId,
680 impl UsePlacementFinder {
681 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
682 let mut finder = UsePlacementFinder {
687 visit::walk_crate(&mut finder, krate);
688 (finder.span, finder.found_use)
692 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
695 module: &'tcx ast::Mod,
697 _: &[ast::Attribute],
700 if self.span.is_some() {
703 if node_id != self.target_module {
704 visit::walk_mod(self, module);
707 // find a use statement
708 for item in &module.items {
710 ItemKind::Use(..) => {
711 // don't suggest placing a use before the prelude
712 // import or other generated ones
713 if item.span.ctxt().outer().expn_info().is_none() {
714 self.span = Some(item.span.shrink_to_lo());
715 self.found_use = true;
719 // don't place use before extern crate
720 ItemKind::ExternCrate(_) => {}
721 // but place them before the first other item
722 _ => if self.span.map_or(true, |span| item.span < span ) {
723 if item.span.ctxt().outer().expn_info().is_none() {
724 // don't insert between attributes and an item
725 if item.attrs.is_empty() {
726 self.span = Some(item.span.shrink_to_lo());
728 // find the first attribute on the item
729 for attr in &item.attrs {
730 if self.span.map_or(true, |span| attr.span < span) {
731 self.span = Some(attr.span.shrink_to_lo());
742 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
743 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
744 fn visit_item(&mut self, item: &'tcx Item) {
745 self.resolve_item(item);
747 fn visit_arm(&mut self, arm: &'tcx Arm) {
748 self.resolve_arm(arm);
750 fn visit_block(&mut self, block: &'tcx Block) {
751 self.resolve_block(block);
753 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
754 debug!("visit_anon_const {:?}", constant);
755 self.with_constant_rib(|this| {
756 visit::walk_anon_const(this, constant);
759 fn visit_expr(&mut self, expr: &'tcx Expr) {
760 self.resolve_expr(expr, None);
762 fn visit_local(&mut self, local: &'tcx Local) {
763 self.resolve_local(local);
765 fn visit_ty(&mut self, ty: &'tcx Ty) {
767 TyKind::Path(ref qself, ref path) => {
768 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
770 TyKind::ImplicitSelf => {
771 let self_ty = keywords::SelfUpper.ident();
772 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
773 .map_or(Def::Err, |d| d.def());
774 self.record_def(ty.id, PathResolution::new(def));
778 visit::walk_ty(self, ty);
780 fn visit_poly_trait_ref(&mut self,
781 tref: &'tcx ast::PolyTraitRef,
782 m: &'tcx ast::TraitBoundModifier) {
783 self.smart_resolve_path(tref.trait_ref.ref_id, None,
784 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
785 visit::walk_poly_trait_ref(self, tref, m);
787 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
788 let generic_params = match foreign_item.node {
789 ForeignItemKind::Fn(_, ref generics) => {
790 HasGenericParams(generics, ItemRibKind)
792 ForeignItemKind::Static(..) => NoGenericParams,
793 ForeignItemKind::Ty => NoGenericParams,
794 ForeignItemKind::Macro(..) => NoGenericParams,
796 self.with_generic_param_rib(generic_params, |this| {
797 visit::walk_foreign_item(this, foreign_item);
800 fn visit_fn(&mut self,
801 function_kind: FnKind<'tcx>,
802 declaration: &'tcx FnDecl,
806 debug!("(resolving function) entering function");
807 let (rib_kind, asyncness) = match function_kind {
808 FnKind::ItemFn(_, ref header, ..) =>
809 (ItemRibKind, header.asyncness.node),
810 FnKind::Method(_, ref sig, _, _) =>
811 (TraitOrImplItemRibKind, sig.header.asyncness.node),
812 FnKind::Closure(_) =>
813 // Async closures aren't resolved through `visit_fn`-- they're
814 // processed separately
815 (ClosureRibKind(node_id), IsAsync::NotAsync),
818 // Create a value rib for the function.
819 self.ribs[ValueNS].push(Rib::new(rib_kind));
821 // Create a label rib for the function.
822 self.label_ribs.push(Rib::new(rib_kind));
824 // Add each argument to the rib.
825 let mut bindings_list = FxHashMap::default();
826 for argument in &declaration.inputs {
827 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
829 self.visit_ty(&argument.ty);
831 debug!("(resolving function) recorded argument");
833 visit::walk_fn_ret_ty(self, &declaration.output);
835 // Resolve the function body, potentially inside the body of an async closure
836 if let IsAsync::Async { closure_id, .. } = asyncness {
837 let rib_kind = ClosureRibKind(closure_id);
838 self.ribs[ValueNS].push(Rib::new(rib_kind));
839 self.label_ribs.push(Rib::new(rib_kind));
842 match function_kind {
843 FnKind::ItemFn(.., body) |
844 FnKind::Method(.., body) => {
845 self.visit_block(body);
847 FnKind::Closure(body) => {
848 self.visit_expr(body);
852 // Leave the body of the async closure
853 if asyncness.is_async() {
854 self.label_ribs.pop();
855 self.ribs[ValueNS].pop();
858 debug!("(resolving function) leaving function");
860 self.label_ribs.pop();
861 self.ribs[ValueNS].pop();
864 fn visit_generics(&mut self, generics: &'tcx Generics) {
865 // For type parameter defaults, we have to ban access
866 // to following type parameters, as the InternalSubsts can only
867 // provide previous type parameters as they're built. We
868 // put all the parameters on the ban list and then remove
869 // them one by one as they are processed and become available.
870 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
871 let mut found_default = false;
872 default_ban_rib.bindings.extend(generics.params.iter()
873 .filter_map(|param| match param.kind {
874 GenericParamKind::Const { .. } |
875 GenericParamKind::Lifetime { .. } => None,
876 GenericParamKind::Type { ref default, .. } => {
877 found_default |= default.is_some();
879 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
886 for param in &generics.params {
888 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
889 GenericParamKind::Type { ref default, .. } => {
890 for bound in ¶m.bounds {
891 self.visit_param_bound(bound);
894 if let Some(ref ty) = default {
895 self.ribs[TypeNS].push(default_ban_rib);
897 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
900 // Allow all following defaults to refer to this type parameter.
901 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
903 GenericParamKind::Const { ref ty } => {
904 for bound in ¶m.bounds {
905 self.visit_param_bound(bound);
912 for p in &generics.where_clause.predicates {
913 self.visit_where_predicate(p);
918 #[derive(Copy, Clone)]
919 enum GenericParameters<'a, 'b> {
921 HasGenericParams(// Type parameters.
924 // The kind of the rib used for type parameters.
928 /// The rib kind controls the translation of local
929 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
930 #[derive(Copy, Clone, Debug)]
932 /// No translation needs to be applied.
935 /// We passed through a closure scope at the given `NodeId`.
936 /// Translate upvars as appropriate.
937 ClosureRibKind(NodeId /* func id */),
939 /// We passed through an impl or trait and are now in one of its
940 /// methods or associated types. Allow references to ty params that impl or trait
941 /// binds. Disallow any other upvars (including other ty params that are
943 TraitOrImplItemRibKind,
945 /// We passed through an item scope. Disallow upvars.
948 /// We're in a constant item. Can't refer to dynamic stuff.
951 /// We passed through a module.
952 ModuleRibKind(Module<'a>),
954 /// We passed through a `macro_rules!` statement
955 MacroDefinition(DefId),
957 /// All bindings in this rib are type parameters that can't be used
958 /// from the default of a type parameter because they're not declared
959 /// before said type parameter. Also see the `visit_generics` override.
960 ForwardTyParamBanRibKind,
963 /// A single local scope.
965 /// A rib represents a scope names can live in. Note that these appear in many places, not just
966 /// around braces. At any place where the list of accessible names (of the given namespace)
967 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
968 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
971 /// Different [rib kinds](enum.RibKind) are transparent for different names.
973 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
974 /// resolving, the name is looked up from inside out.
977 bindings: FxHashMap<Ident, Def>,
982 fn new(kind: RibKind<'a>) -> Rib<'a> {
984 bindings: Default::default(),
990 /// An intermediate resolution result.
992 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
993 /// items are visible in their whole block, while defs only from the place they are defined
995 enum LexicalScopeBinding<'a> {
996 Item(&'a NameBinding<'a>),
1000 impl<'a> LexicalScopeBinding<'a> {
1001 fn item(self) -> Option<&'a NameBinding<'a>> {
1003 LexicalScopeBinding::Item(binding) => Some(binding),
1008 fn def(self) -> Def {
1010 LexicalScopeBinding::Item(binding) => binding.def(),
1011 LexicalScopeBinding::Def(def) => def,
1016 #[derive(Copy, Clone, Debug)]
1017 enum ModuleOrUniformRoot<'a> {
1021 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1022 CrateRootAndExternPrelude,
1024 /// Virtual module that denotes resolution in extern prelude.
1025 /// Used for paths starting with `::` on 2018 edition.
1028 /// Virtual module that denotes resolution in current scope.
1029 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1030 /// are always split into two parts, the first of which should be some kind of module.
1034 impl ModuleOrUniformRoot<'_> {
1035 fn same_def(lhs: Self, rhs: Self) -> bool {
1037 (ModuleOrUniformRoot::Module(lhs),
1038 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1039 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1040 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1041 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1042 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1048 #[derive(Clone, Debug)]
1049 enum PathResult<'a> {
1050 Module(ModuleOrUniformRoot<'a>),
1051 NonModule(PathResolution),
1053 Failed(Span, String, bool /* is the error from the last segment? */),
1057 /// An anonymous module; e.g., just a block.
1061 /// fn f() {} // (1)
1062 /// { // This is an anonymous module
1063 /// f(); // This resolves to (2) as we are inside the block.
1064 /// fn f() {} // (2)
1066 /// f(); // Resolves to (1)
1070 /// Any module with a name.
1074 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1075 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1080 /// One node in the tree of modules.
1081 pub struct ModuleData<'a> {
1082 parent: Option<Module<'a>>,
1085 // The def id of the closest normal module (`mod`) ancestor (including this module).
1086 normal_ancestor_id: DefId,
1088 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1089 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1090 Option<&'a NameBinding<'a>>)>>,
1091 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1093 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1095 // Macro invocations that can expand into items in this module.
1096 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1098 no_implicit_prelude: bool,
1100 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1101 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1103 // Used to memoize the traits in this module for faster searches through all traits in scope.
1104 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1106 // Whether this module is populated. If not populated, any attempt to
1107 // access the children must be preceded with a
1108 // `populate_module_if_necessary` call.
1109 populated: Cell<bool>,
1111 /// Span of the module itself. Used for error reporting.
1117 type Module<'a> = &'a ModuleData<'a>;
1119 impl<'a> ModuleData<'a> {
1120 fn new(parent: Option<Module<'a>>,
1122 normal_ancestor_id: DefId,
1124 span: Span) -> Self {
1129 resolutions: Default::default(),
1130 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1131 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1132 builtin_attrs: RefCell::new(Vec::new()),
1133 unresolved_invocations: Default::default(),
1134 no_implicit_prelude: false,
1135 glob_importers: RefCell::new(Vec::new()),
1136 globs: RefCell::new(Vec::new()),
1137 traits: RefCell::new(None),
1138 populated: Cell::new(normal_ancestor_id.is_local()),
1144 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1145 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1146 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1150 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1151 let resolutions = self.resolutions.borrow();
1152 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1153 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1154 for &(&(ident, ns), &resolution) in resolutions.iter() {
1155 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1159 fn def(&self) -> Option<Def> {
1161 ModuleKind::Def(def, _) => Some(def),
1166 fn def_id(&self) -> Option<DefId> {
1167 self.def().as_ref().map(Def::def_id)
1170 // `self` resolves to the first module ancestor that `is_normal`.
1171 fn is_normal(&self) -> bool {
1173 ModuleKind::Def(Def::Mod(_), _) => true,
1178 fn is_trait(&self) -> bool {
1180 ModuleKind::Def(Def::Trait(_), _) => true,
1185 fn nearest_item_scope(&'a self) -> Module<'a> {
1186 if self.is_trait() { self.parent.unwrap() } else { self }
1189 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1190 while !ptr::eq(self, other) {
1191 if let Some(parent) = other.parent {
1201 impl<'a> fmt::Debug for ModuleData<'a> {
1202 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1203 write!(f, "{:?}", self.def())
1207 /// Records a possibly-private value, type, or module definition.
1208 #[derive(Clone, Debug)]
1209 pub struct NameBinding<'a> {
1210 kind: NameBindingKind<'a>,
1211 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1214 vis: ty::Visibility,
1217 pub trait ToNameBinding<'a> {
1218 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1221 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1222 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1227 #[derive(Clone, Debug)]
1228 enum NameBindingKind<'a> {
1229 Def(Def, /* is_macro_export */ bool),
1232 binding: &'a NameBinding<'a>,
1233 directive: &'a ImportDirective<'a>,
1238 impl<'a> NameBindingKind<'a> {
1239 /// Is this a name binding of a import?
1240 fn is_import(&self) -> bool {
1242 NameBindingKind::Import { .. } => true,
1248 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1250 struct UseError<'a> {
1251 err: DiagnosticBuilder<'a>,
1252 /// Attach `use` statements for these candidates.
1253 candidates: Vec<ImportSuggestion>,
1254 /// The `NodeId` of the module to place the use-statements in.
1256 /// Whether the diagnostic should state that it's "better".
1260 #[derive(Clone, Copy, PartialEq, Debug)]
1261 enum AmbiguityKind {
1266 LegacyHelperVsPrelude,
1271 MoreExpandedVsOuter,
1274 impl AmbiguityKind {
1275 fn descr(self) -> &'static str {
1277 AmbiguityKind::Import =>
1278 "name vs any other name during import resolution",
1279 AmbiguityKind::AbsolutePath =>
1280 "name in the crate root vs extern crate during absolute path resolution",
1281 AmbiguityKind::BuiltinAttr =>
1282 "built-in attribute vs any other name",
1283 AmbiguityKind::DeriveHelper =>
1284 "derive helper attribute vs any other name",
1285 AmbiguityKind::LegacyHelperVsPrelude =>
1286 "legacy plugin helper attribute vs name from prelude",
1287 AmbiguityKind::LegacyVsModern =>
1288 "`macro_rules` vs non-`macro_rules` from other module",
1289 AmbiguityKind::GlobVsOuter =>
1290 "glob import vs any other name from outer scope during import/macro resolution",
1291 AmbiguityKind::GlobVsGlob =>
1292 "glob import vs glob import in the same module",
1293 AmbiguityKind::GlobVsExpanded =>
1294 "glob import vs macro-expanded name in the same \
1295 module during import/macro resolution",
1296 AmbiguityKind::MoreExpandedVsOuter =>
1297 "macro-expanded name vs less macro-expanded name \
1298 from outer scope during import/macro resolution",
1303 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1304 #[derive(Clone, Copy, PartialEq)]
1305 enum AmbiguityErrorMisc {
1312 struct AmbiguityError<'a> {
1313 kind: AmbiguityKind,
1315 b1: &'a NameBinding<'a>,
1316 b2: &'a NameBinding<'a>,
1317 misc1: AmbiguityErrorMisc,
1318 misc2: AmbiguityErrorMisc,
1321 impl<'a> NameBinding<'a> {
1322 fn module(&self) -> Option<Module<'a>> {
1324 NameBindingKind::Module(module) => Some(module),
1325 NameBindingKind::Import { binding, .. } => binding.module(),
1330 fn def(&self) -> Def {
1332 NameBindingKind::Def(def, _) => def,
1333 NameBindingKind::Module(module) => module.def().unwrap(),
1334 NameBindingKind::Import { binding, .. } => binding.def(),
1338 fn is_ambiguity(&self) -> bool {
1339 self.ambiguity.is_some() || match self.kind {
1340 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1345 // We sometimes need to treat variants as `pub` for backwards compatibility
1346 fn pseudo_vis(&self) -> ty::Visibility {
1347 if self.is_variant() && self.def().def_id().is_local() {
1348 ty::Visibility::Public
1354 fn is_variant(&self) -> bool {
1356 NameBindingKind::Def(Def::Variant(..), _) |
1357 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1362 fn is_extern_crate(&self) -> bool {
1364 NameBindingKind::Import {
1365 directive: &ImportDirective {
1366 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1369 NameBindingKind::Module(
1370 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1371 ) => def_id.index == CRATE_DEF_INDEX,
1376 fn is_import(&self) -> bool {
1378 NameBindingKind::Import { .. } => true,
1383 fn is_glob_import(&self) -> bool {
1385 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1390 fn is_importable(&self) -> bool {
1392 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1397 fn is_macro_def(&self) -> bool {
1399 NameBindingKind::Def(Def::Macro(..), _) => true,
1404 fn macro_kind(&self) -> Option<MacroKind> {
1406 Def::Macro(_, kind) => Some(kind),
1407 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1412 fn descr(&self) -> &'static str {
1413 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1416 fn article(&self) -> &'static str {
1417 if self.is_extern_crate() { "an" } else { self.def().article() }
1420 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1421 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1422 // Then this function returns `true` if `self` may emerge from a macro *after* that
1423 // in some later round and screw up our previously found resolution.
1424 // See more detailed explanation in
1425 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1426 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1427 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1428 // Expansions are partially ordered, so "may appear after" is an inversion of
1429 // "certainly appears before or simultaneously" and includes unordered cases.
1430 let self_parent_expansion = self.expansion;
1431 let other_parent_expansion = binding.expansion;
1432 let certainly_before_other_or_simultaneously =
1433 other_parent_expansion.is_descendant_of(self_parent_expansion);
1434 let certainly_before_invoc_or_simultaneously =
1435 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1436 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1440 /// Interns the names of the primitive types.
1442 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1443 /// special handling, since they have no place of origin.
1445 struct PrimitiveTypeTable {
1446 primitive_types: FxHashMap<Name, PrimTy>,
1449 impl PrimitiveTypeTable {
1450 fn new() -> PrimitiveTypeTable {
1451 let mut table = PrimitiveTypeTable::default();
1453 table.intern("bool", Bool);
1454 table.intern("char", Char);
1455 table.intern("f32", Float(FloatTy::F32));
1456 table.intern("f64", Float(FloatTy::F64));
1457 table.intern("isize", Int(IntTy::Isize));
1458 table.intern("i8", Int(IntTy::I8));
1459 table.intern("i16", Int(IntTy::I16));
1460 table.intern("i32", Int(IntTy::I32));
1461 table.intern("i64", Int(IntTy::I64));
1462 table.intern("i128", Int(IntTy::I128));
1463 table.intern("str", Str);
1464 table.intern("usize", Uint(UintTy::Usize));
1465 table.intern("u8", Uint(UintTy::U8));
1466 table.intern("u16", Uint(UintTy::U16));
1467 table.intern("u32", Uint(UintTy::U32));
1468 table.intern("u64", Uint(UintTy::U64));
1469 table.intern("u128", Uint(UintTy::U128));
1473 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1474 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1478 #[derive(Debug, Default, Clone)]
1479 pub struct ExternPreludeEntry<'a> {
1480 extern_crate_item: Option<&'a NameBinding<'a>>,
1481 pub introduced_by_item: bool,
1484 /// The main resolver class.
1486 /// This is the visitor that walks the whole crate.
1487 pub struct Resolver<'a> {
1488 session: &'a Session,
1491 pub definitions: Definitions,
1493 graph_root: Module<'a>,
1495 prelude: Option<Module<'a>>,
1496 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1498 /// N.B., this is used only for better diagnostics, not name resolution itself.
1499 has_self: FxHashSet<DefId>,
1501 /// Names of fields of an item `DefId` accessible with dot syntax.
1502 /// Used for hints during error reporting.
1503 field_names: FxHashMap<DefId, Vec<Name>>,
1505 /// All imports known to succeed or fail.
1506 determined_imports: Vec<&'a ImportDirective<'a>>,
1508 /// All non-determined imports.
1509 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1511 /// The module that represents the current item scope.
1512 current_module: Module<'a>,
1514 /// The current set of local scopes for types and values.
1515 /// FIXME #4948: Reuse ribs to avoid allocation.
1516 ribs: PerNS<Vec<Rib<'a>>>,
1518 /// The current set of local scopes, for labels.
1519 label_ribs: Vec<Rib<'a>>,
1521 /// The trait that the current context can refer to.
1522 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1524 /// The current self type if inside an impl (used for better errors).
1525 current_self_type: Option<Ty>,
1527 /// The current self item if inside an ADT (used for better errors).
1528 current_self_item: Option<NodeId>,
1530 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1531 /// We are resolving a last import segment during import validation.
1532 last_import_segment: bool,
1533 /// This binding should be ignored during in-module resolution, so that we don't get
1534 /// "self-confirming" import resolutions during import validation.
1535 blacklisted_binding: Option<&'a NameBinding<'a>>,
1537 /// The idents for the primitive types.
1538 primitive_type_table: PrimitiveTypeTable,
1541 import_map: ImportMap,
1542 pub freevars: FreevarMap,
1543 freevars_seen: NodeMap<NodeMap<usize>>,
1544 pub export_map: ExportMap,
1545 pub trait_map: TraitMap,
1547 /// A map from nodes to anonymous modules.
1548 /// Anonymous modules are pseudo-modules that are implicitly created around items
1549 /// contained within blocks.
1551 /// For example, if we have this:
1559 /// There will be an anonymous module created around `g` with the ID of the
1560 /// entry block for `f`.
1561 block_map: NodeMap<Module<'a>>,
1562 module_map: FxHashMap<DefId, Module<'a>>,
1563 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1564 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1566 /// Maps glob imports to the names of items actually imported.
1567 pub glob_map: GlobMap,
1569 used_imports: FxHashSet<(NodeId, Namespace)>,
1570 pub maybe_unused_trait_imports: NodeSet,
1571 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1573 /// A list of labels as of yet unused. Labels will be removed from this map when
1574 /// they are used (in a `break` or `continue` statement)
1575 pub unused_labels: FxHashMap<NodeId, Span>,
1577 /// Privacy errors are delayed until the end in order to deduplicate them.
1578 privacy_errors: Vec<PrivacyError<'a>>,
1579 /// Ambiguity errors are delayed for deduplication.
1580 ambiguity_errors: Vec<AmbiguityError<'a>>,
1581 /// `use` injections are delayed for better placement and deduplication.
1582 use_injections: Vec<UseError<'a>>,
1583 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
1584 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1586 arenas: &'a ResolverArenas<'a>,
1587 dummy_binding: &'a NameBinding<'a>,
1589 crate_loader: &'a mut CrateLoader<'a>,
1590 macro_names: FxHashSet<Ident>,
1591 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1592 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1593 pub all_macros: FxHashMap<Name, Def>,
1594 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1595 macro_defs: FxHashMap<Mark, DefId>,
1596 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1598 /// List of crate local macros that we need to warn about as being unused.
1599 /// Right now this only includes macro_rules! macros, and macros 2.0.
1600 unused_macros: FxHashSet<DefId>,
1602 /// Maps the `Mark` of an expansion to its containing module or block.
1603 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1605 /// Avoid duplicated errors for "name already defined".
1606 name_already_seen: FxHashMap<Name, Span>,
1608 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1610 /// Table for mapping struct IDs into struct constructor IDs,
1611 /// it's not used during normal resolution, only for better error reporting.
1612 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1614 /// Only used for better errors on `fn(): fn()`.
1615 current_type_ascription: Vec<Span>,
1617 injected_crate: Option<Module<'a>>,
1620 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1622 pub struct ResolverArenas<'a> {
1623 modules: arena::TypedArena<ModuleData<'a>>,
1624 local_modules: RefCell<Vec<Module<'a>>>,
1625 name_bindings: arena::TypedArena<NameBinding<'a>>,
1626 import_directives: arena::TypedArena<ImportDirective<'a>>,
1627 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1628 invocation_data: arena::TypedArena<InvocationData<'a>>,
1629 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1632 impl<'a> ResolverArenas<'a> {
1633 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1634 let module = self.modules.alloc(module);
1635 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1636 self.local_modules.borrow_mut().push(module);
1640 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1641 self.local_modules.borrow()
1643 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1644 self.name_bindings.alloc(name_binding)
1646 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1647 -> &'a ImportDirective<'_> {
1648 self.import_directives.alloc(import_directive)
1650 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1651 self.name_resolutions.alloc(Default::default())
1653 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1654 -> &'a InvocationData<'a> {
1655 self.invocation_data.alloc(expansion_data)
1657 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1658 self.legacy_bindings.alloc(binding)
1662 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1663 fn parent(self, id: DefId) -> Option<DefId> {
1665 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1666 _ => self.cstore.def_key(id).parent,
1667 }.map(|index| DefId { index, ..id })
1671 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1672 /// the resolver is no longer needed as all the relevant information is inline.
1673 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1674 fn resolve_hir_path(
1679 self.resolve_hir_path_cb(path, is_value,
1680 |resolver, span, error| resolve_error(resolver, span, error))
1683 fn resolve_str_path(
1686 crate_root: Option<&str>,
1687 components: &[&str],
1690 let segments = iter::once(keywords::PathRoot.ident())
1692 crate_root.into_iter()
1693 .chain(components.iter().cloned())
1694 .map(Ident::from_str)
1695 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1698 let path = ast::Path {
1703 self.resolve_hir_path(&path, is_value)
1706 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1707 self.def_map.get(&id).cloned()
1710 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1711 self.import_map.get(&id).cloned().unwrap_or_default()
1714 fn definitions(&mut self) -> &mut Definitions {
1715 &mut self.definitions
1719 impl<'a> Resolver<'a> {
1720 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
1721 /// isn't something that can be returned because it can't be made to live that long,
1722 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1723 /// just that an error occurred.
1724 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1725 -> Result<hir::Path, ()> {
1727 let mut errored = false;
1729 let path = if path_str.starts_with("::") {
1732 segments: iter::once(keywords::PathRoot.ident())
1734 path_str.split("::").skip(1).map(Ident::from_str)
1736 .map(|i| self.new_ast_path_segment(i))
1744 .map(Ident::from_str)
1745 .map(|i| self.new_ast_path_segment(i))
1749 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1750 if errored || path.def == Def::Err {
1757 /// Like `resolve_hir_path`, but takes a callback in case there was an error.
1758 fn resolve_hir_path_cb<F>(
1764 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1766 let namespace = if is_value { ValueNS } else { TypeNS };
1767 let span = path.span;
1768 let segments = &path.segments;
1769 let path = Segment::from_path(&path);
1770 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
1771 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1772 span, CrateLint::No) {
1773 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1774 module.def().unwrap(),
1775 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1776 path_res.base_def(),
1777 PathResult::NonModule(..) => {
1778 let msg = "type-relative paths are not supported in this context";
1779 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1782 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1783 PathResult::Failed(span, msg, _) => {
1784 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1789 let segments: Vec<_> = segments.iter().map(|seg| {
1790 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1791 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1797 segments: segments.into(),
1801 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1802 let mut seg = ast::PathSegment::from_ident(ident);
1803 seg.id = self.session.next_node_id();
1808 impl<'a> Resolver<'a> {
1809 pub fn new(session: &'a Session,
1813 crate_loader: &'a mut CrateLoader<'a>,
1814 arenas: &'a ResolverArenas<'a>)
1816 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1817 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1818 let graph_root = arenas.alloc_module(ModuleData {
1819 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1820 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1822 let mut module_map = FxHashMap::default();
1823 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1825 let mut definitions = Definitions::new();
1826 DefCollector::new(&mut definitions, Mark::root())
1827 .collect_root(crate_name, session.local_crate_disambiguator());
1829 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1830 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1833 if !attr::contains_name(&krate.attrs, "no_core") {
1834 extern_prelude.insert(Ident::from_str("core"), Default::default());
1835 if !attr::contains_name(&krate.attrs, "no_std") {
1836 extern_prelude.insert(Ident::from_str("std"), Default::default());
1837 if session.rust_2018() {
1838 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1843 let mut invocations = FxHashMap::default();
1844 invocations.insert(Mark::root(),
1845 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1847 let mut macro_defs = FxHashMap::default();
1848 macro_defs.insert(Mark::root(), root_def_id);
1857 // The outermost module has def ID 0; this is not reflected in the
1863 has_self: FxHashSet::default(),
1864 field_names: FxHashMap::default(),
1866 determined_imports: Vec::new(),
1867 indeterminate_imports: Vec::new(),
1869 current_module: graph_root,
1871 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1872 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1873 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1875 label_ribs: Vec::new(),
1877 current_trait_ref: None,
1878 current_self_type: None,
1879 current_self_item: None,
1880 last_import_segment: false,
1881 blacklisted_binding: None,
1883 primitive_type_table: PrimitiveTypeTable::new(),
1885 def_map: Default::default(),
1886 import_map: Default::default(),
1887 freevars: Default::default(),
1888 freevars_seen: Default::default(),
1889 export_map: FxHashMap::default(),
1890 trait_map: Default::default(),
1892 block_map: Default::default(),
1893 extern_module_map: FxHashMap::default(),
1894 binding_parent_modules: FxHashMap::default(),
1896 glob_map: Default::default(),
1898 used_imports: FxHashSet::default(),
1899 maybe_unused_trait_imports: Default::default(),
1900 maybe_unused_extern_crates: Vec::new(),
1902 unused_labels: FxHashMap::default(),
1904 privacy_errors: Vec::new(),
1905 ambiguity_errors: Vec::new(),
1906 use_injections: Vec::new(),
1907 macro_expanded_macro_export_errors: BTreeSet::new(),
1910 dummy_binding: arenas.alloc_name_binding(NameBinding {
1911 kind: NameBindingKind::Def(Def::Err, false),
1913 expansion: Mark::root(),
1915 vis: ty::Visibility::Public,
1919 macro_names: FxHashSet::default(),
1920 builtin_macros: FxHashMap::default(),
1921 macro_use_prelude: FxHashMap::default(),
1922 all_macros: FxHashMap::default(),
1923 macro_map: FxHashMap::default(),
1926 local_macro_def_scopes: FxHashMap::default(),
1927 name_already_seen: FxHashMap::default(),
1928 potentially_unused_imports: Vec::new(),
1929 struct_constructors: Default::default(),
1930 unused_macros: FxHashSet::default(),
1931 current_type_ascription: Vec::new(),
1932 injected_crate: None,
1936 pub fn arenas() -> ResolverArenas<'a> {
1940 /// Runs the function on each namespace.
1941 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1947 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1949 match self.macro_defs.get(&ctxt.outer()) {
1950 Some(&def_id) => return def_id,
1951 None => ctxt.remove_mark(),
1956 /// Entry point to crate resolution.
1957 pub fn resolve_crate(&mut self, krate: &Crate) {
1958 ImportResolver { resolver: self }.finalize_imports();
1959 self.current_module = self.graph_root;
1960 self.finalize_current_module_macro_resolutions();
1962 visit::walk_crate(self, krate);
1964 check_unused::check_crate(self, krate);
1965 self.report_errors(krate);
1966 self.crate_loader.postprocess(krate);
1973 normal_ancestor_id: DefId,
1977 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1978 self.arenas.alloc_module(module)
1981 fn record_use(&mut self, ident: Ident, ns: Namespace,
1982 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1983 if let Some((b2, kind)) = used_binding.ambiguity {
1984 self.ambiguity_errors.push(AmbiguityError {
1985 kind, ident, b1: used_binding, b2,
1986 misc1: AmbiguityErrorMisc::None,
1987 misc2: AmbiguityErrorMisc::None,
1990 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1991 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1992 // but not introduce it, as used if they are accessed from lexical scope.
1993 if is_lexical_scope {
1994 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1995 if let Some(crate_item) = entry.extern_crate_item {
1996 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2003 directive.used.set(true);
2004 self.used_imports.insert((directive.id, ns));
2005 self.add_to_glob_map(&directive, ident);
2006 self.record_use(ident, ns, binding, false);
2011 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2012 if directive.is_glob() {
2013 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2017 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2018 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2019 /// `ident` in the first scope that defines it (or None if no scopes define it).
2021 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2022 /// the items are defined in the block. For example,
2025 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2028 /// g(); // This resolves to the local variable `g` since it shadows the item.
2032 /// Invariant: This must only be called during main resolution, not during
2033 /// import resolution.
2034 fn resolve_ident_in_lexical_scope(&mut self,
2037 record_used_id: Option<NodeId>,
2039 -> Option<LexicalScopeBinding<'a>> {
2040 assert!(ns == TypeNS || ns == ValueNS);
2041 if ident.name == keywords::Invalid.name() {
2042 return Some(LexicalScopeBinding::Def(Def::Err));
2044 ident.span = if ident.name == keywords::SelfUpper.name() {
2045 // FIXME(jseyfried) improve `Self` hygiene
2046 ident.span.with_ctxt(SyntaxContext::empty())
2047 } else if ns == TypeNS {
2050 ident.span.modern_and_legacy()
2053 // Walk backwards up the ribs in scope.
2054 let record_used = record_used_id.is_some();
2055 let mut module = self.graph_root;
2056 for i in (0 .. self.ribs[ns].len()).rev() {
2057 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2058 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2059 // The ident resolves to a type parameter or local variable.
2060 return Some(LexicalScopeBinding::Def(
2061 self.adjust_local_def(ns, i, def, record_used, path_span)
2065 module = match self.ribs[ns][i].kind {
2066 ModuleRibKind(module) => module,
2067 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2068 // If an invocation of this macro created `ident`, give up on `ident`
2069 // and switch to `ident`'s source from the macro definition.
2070 ident.span.remove_mark();
2076 let item = self.resolve_ident_in_module_unadjusted(
2077 ModuleOrUniformRoot::Module(module),
2083 if let Ok(binding) = item {
2084 // The ident resolves to an item.
2085 return Some(LexicalScopeBinding::Item(binding));
2089 ModuleKind::Block(..) => {}, // We can see through blocks
2094 ident.span = ident.span.modern();
2095 let mut poisoned = None;
2097 let opt_module = if let Some(node_id) = record_used_id {
2098 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2099 node_id, &mut poisoned)
2101 self.hygienic_lexical_parent(module, &mut ident.span)
2103 module = unwrap_or!(opt_module, break);
2104 let orig_current_module = self.current_module;
2105 self.current_module = module; // Lexical resolutions can never be a privacy error.
2106 let result = self.resolve_ident_in_module_unadjusted(
2107 ModuleOrUniformRoot::Module(module),
2113 self.current_module = orig_current_module;
2117 if let Some(node_id) = poisoned {
2118 self.session.buffer_lint_with_diagnostic(
2119 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2120 node_id, ident.span,
2121 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2122 lint::builtin::BuiltinLintDiagnostics::
2123 ProcMacroDeriveResolutionFallback(ident.span),
2126 return Some(LexicalScopeBinding::Item(binding))
2128 Err(Determined) => continue,
2129 Err(Undetermined) =>
2130 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2134 if !module.no_implicit_prelude {
2136 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2137 return Some(LexicalScopeBinding::Item(binding));
2140 if ns == TypeNS && is_known_tool(ident.name) {
2141 let binding = (Def::ToolMod, ty::Visibility::Public,
2142 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2143 return Some(LexicalScopeBinding::Item(binding));
2145 if let Some(prelude) = self.prelude {
2146 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2147 ModuleOrUniformRoot::Module(prelude),
2153 return Some(LexicalScopeBinding::Item(binding));
2161 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2162 -> Option<Module<'a>> {
2163 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2164 return Some(self.macro_def_scope(span.remove_mark()));
2167 if let ModuleKind::Block(..) = module.kind {
2168 return Some(module.parent.unwrap());
2174 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2175 span: &mut Span, node_id: NodeId,
2176 poisoned: &mut Option<NodeId>)
2177 -> Option<Module<'a>> {
2178 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2182 // We need to support the next case under a deprecation warning
2185 // ---- begin: this comes from a proc macro derive
2186 // mod implementation_details {
2187 // // Note that `MyStruct` is not in scope here.
2188 // impl SomeTrait for MyStruct { ... }
2192 // So we have to fall back to the module's parent during lexical resolution in this case.
2193 if let Some(parent) = module.parent {
2194 // Inner module is inside the macro, parent module is outside of the macro.
2195 if module.expansion != parent.expansion &&
2196 module.expansion.is_descendant_of(parent.expansion) {
2197 // The macro is a proc macro derive
2198 if module.expansion.looks_like_proc_macro_derive() {
2199 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2200 *poisoned = Some(node_id);
2201 return module.parent;
2210 fn resolve_ident_in_module(
2212 module: ModuleOrUniformRoot<'a>,
2215 parent_scope: Option<&ParentScope<'a>>,
2218 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2219 self.resolve_ident_in_module_ext(
2220 module, ident, ns, parent_scope, record_used, path_span
2221 ).map_err(|(determinacy, _)| determinacy)
2224 fn resolve_ident_in_module_ext(
2226 module: ModuleOrUniformRoot<'a>,
2229 parent_scope: Option<&ParentScope<'a>>,
2232 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2233 let orig_current_module = self.current_module;
2235 ModuleOrUniformRoot::Module(module) => {
2236 ident.span = ident.span.modern();
2237 if let Some(def) = ident.span.adjust(module.expansion) {
2238 self.current_module = self.macro_def_scope(def);
2241 ModuleOrUniformRoot::ExternPrelude => {
2242 ident.span = ident.span.modern();
2243 ident.span.adjust(Mark::root());
2245 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2246 ModuleOrUniformRoot::CurrentScope => {
2250 let result = self.resolve_ident_in_module_unadjusted_ext(
2251 module, ident, ns, parent_scope, false, record_used, path_span,
2253 self.current_module = orig_current_module;
2257 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2258 let mut ctxt = ident.span.ctxt();
2259 let mark = if ident.name == keywords::DollarCrate.name() {
2260 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2261 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2262 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2263 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2264 // definitions actually produced by `macro` and `macro` definitions produced by
2265 // `macro_rules!`, but at least such configurations are not stable yet.
2266 ctxt = ctxt.modern_and_legacy();
2267 let mut iter = ctxt.marks().into_iter().rev().peekable();
2268 let mut result = None;
2269 // Find the last modern mark from the end if it exists.
2270 while let Some(&(mark, transparency)) = iter.peek() {
2271 if transparency == Transparency::Opaque {
2272 result = Some(mark);
2278 // Then find the last legacy mark from the end if it exists.
2279 for (mark, transparency) in iter {
2280 if transparency == Transparency::SemiTransparent {
2281 result = Some(mark);
2288 ctxt = ctxt.modern();
2289 ctxt.adjust(Mark::root())
2291 let module = match mark {
2292 Some(def) => self.macro_def_scope(def),
2293 None => return self.graph_root,
2295 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2298 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2299 let mut module = self.get_module(module.normal_ancestor_id);
2300 while module.span.ctxt().modern() != *ctxt {
2301 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2302 module = self.get_module(parent.normal_ancestor_id);
2309 // We maintain a list of value ribs and type ribs.
2311 // Simultaneously, we keep track of the current position in the module
2312 // graph in the `current_module` pointer. When we go to resolve a name in
2313 // the value or type namespaces, we first look through all the ribs and
2314 // then query the module graph. When we resolve a name in the module
2315 // namespace, we can skip all the ribs (since nested modules are not
2316 // allowed within blocks in Rust) and jump straight to the current module
2319 // Named implementations are handled separately. When we find a method
2320 // call, we consult the module node to find all of the implementations in
2321 // scope. This information is lazily cached in the module node. We then
2322 // generate a fake "implementation scope" containing all the
2323 // implementations thus found, for compatibility with old resolve pass.
2325 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2326 where F: FnOnce(&mut Resolver<'_>) -> T
2328 let id = self.definitions.local_def_id(id);
2329 let module = self.module_map.get(&id).cloned(); // clones a reference
2330 if let Some(module) = module {
2331 // Move down in the graph.
2332 let orig_module = replace(&mut self.current_module, module);
2333 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2334 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2336 self.finalize_current_module_macro_resolutions();
2339 self.current_module = orig_module;
2340 self.ribs[ValueNS].pop();
2341 self.ribs[TypeNS].pop();
2348 /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
2349 /// is returned by the given predicate function
2351 /// Stops after meeting a closure.
2352 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2353 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2355 for rib in self.label_ribs.iter().rev() {
2358 // If an invocation of this macro created `ident`, give up on `ident`
2359 // and switch to `ident`'s source from the macro definition.
2360 MacroDefinition(def) => {
2361 if def == self.macro_def(ident.span.ctxt()) {
2362 ident.span.remove_mark();
2366 // Do not resolve labels across function boundary
2370 let r = pred(rib, ident);
2378 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2379 debug!("resolve_adt");
2380 self.with_current_self_item(item, |this| {
2381 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2382 let item_def_id = this.definitions.local_def_id(item.id);
2383 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2384 visit::walk_item(this, item);
2390 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2391 let segments = &use_tree.prefix.segments;
2392 if !segments.is_empty() {
2393 let ident = segments[0].ident;
2394 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2398 let nss = match use_tree.kind {
2399 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2402 let report_error = |this: &Self, ns| {
2403 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2404 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2408 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2409 Some(LexicalScopeBinding::Def(..)) => {
2410 report_error(self, ns);
2412 Some(LexicalScopeBinding::Item(binding)) => {
2413 let orig_blacklisted_binding =
2414 mem::replace(&mut self.blacklisted_binding, Some(binding));
2415 if let Some(LexicalScopeBinding::Def(..)) =
2416 self.resolve_ident_in_lexical_scope(ident, ns, None,
2417 use_tree.prefix.span) {
2418 report_error(self, ns);
2420 self.blacklisted_binding = orig_blacklisted_binding;
2425 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2426 for (use_tree, _) in use_trees {
2427 self.future_proof_import(use_tree);
2432 fn resolve_item(&mut self, item: &Item) {
2433 let name = item.ident.name;
2434 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2437 ItemKind::Ty(_, ref generics) |
2438 ItemKind::Fn(_, _, ref generics, _) |
2439 ItemKind::Existential(_, ref generics) => {
2440 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2441 |this| visit::walk_item(this, item));
2444 ItemKind::Enum(_, ref generics) |
2445 ItemKind::Struct(_, ref generics) |
2446 ItemKind::Union(_, ref generics) => {
2447 self.resolve_adt(item, generics);
2450 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2451 self.resolve_implementation(generics,
2457 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2458 // Create a new rib for the trait-wide type parameters.
2459 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2460 let local_def_id = this.definitions.local_def_id(item.id);
2461 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2462 this.visit_generics(generics);
2463 walk_list!(this, visit_param_bound, bounds);
2465 for trait_item in trait_items {
2466 let generic_params = HasGenericParams(&trait_item.generics,
2467 TraitOrImplItemRibKind);
2468 this.with_generic_param_rib(generic_params, |this| {
2469 match trait_item.node {
2470 TraitItemKind::Const(ref ty, ref default) => {
2473 // Only impose the restrictions of
2474 // ConstRibKind for an actual constant
2475 // expression in a provided default.
2476 if let Some(ref expr) = *default{
2477 this.with_constant_rib(|this| {
2478 this.visit_expr(expr);
2482 TraitItemKind::Method(_, _) => {
2483 visit::walk_trait_item(this, trait_item)
2485 TraitItemKind::Type(..) => {
2486 visit::walk_trait_item(this, trait_item)
2488 TraitItemKind::Macro(_) => {
2489 panic!("unexpanded macro in resolve!")
2498 ItemKind::TraitAlias(ref generics, ref bounds) => {
2499 // Create a new rib for the trait-wide type parameters.
2500 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2501 let local_def_id = this.definitions.local_def_id(item.id);
2502 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2503 this.visit_generics(generics);
2504 walk_list!(this, visit_param_bound, bounds);
2509 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2510 self.with_scope(item.id, |this| {
2511 visit::walk_item(this, item);
2515 ItemKind::Static(ref ty, _, ref expr) |
2516 ItemKind::Const(ref ty, ref expr) => {
2517 debug!("resolve_item ItemKind::Const");
2518 self.with_item_rib(|this| {
2520 this.with_constant_rib(|this| {
2521 this.visit_expr(expr);
2526 ItemKind::Use(ref use_tree) => {
2527 self.future_proof_import(use_tree);
2530 ItemKind::ExternCrate(..) |
2531 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2532 // do nothing, these are just around to be encoded
2535 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2539 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2540 where F: FnOnce(&mut Resolver<'_>)
2542 debug!("with_generic_param_rib");
2543 match generic_params {
2544 HasGenericParams(generics, rib_kind) => {
2545 let mut function_type_rib = Rib::new(rib_kind);
2546 let mut function_value_rib = Rib::new(rib_kind);
2547 let mut seen_bindings = FxHashMap::default();
2548 for param in &generics.params {
2550 GenericParamKind::Lifetime { .. } => {}
2551 GenericParamKind::Type { .. } => {
2552 let ident = param.ident.modern();
2553 debug!("with_generic_param_rib: {}", param.id);
2555 if seen_bindings.contains_key(&ident) {
2556 let span = seen_bindings.get(&ident).unwrap();
2557 let err = ResolutionError::NameAlreadyUsedInParameterList(
2561 resolve_error(self, param.ident.span, err);
2563 seen_bindings.entry(ident).or_insert(param.ident.span);
2565 // Plain insert (no renaming).
2566 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2567 function_type_rib.bindings.insert(ident, def);
2568 self.record_def(param.id, PathResolution::new(def));
2570 GenericParamKind::Const { .. } => {
2571 let ident = param.ident.modern();
2572 debug!("with_generic_param_rib: {}", param.id);
2574 if seen_bindings.contains_key(&ident) {
2575 let span = seen_bindings.get(&ident).unwrap();
2576 let err = ResolutionError::NameAlreadyUsedInParameterList(
2580 resolve_error(self, param.ident.span, err);
2582 seen_bindings.entry(ident).or_insert(param.ident.span);
2584 let def = Def::ConstParam(self.definitions.local_def_id(param.id));
2585 function_value_rib.bindings.insert(ident, def);
2586 self.record_def(param.id, PathResolution::new(def));
2590 self.ribs[ValueNS].push(function_value_rib);
2591 self.ribs[TypeNS].push(function_type_rib);
2594 NoGenericParams => {
2601 if let HasGenericParams(..) = generic_params {
2602 self.ribs[TypeNS].pop();
2603 self.ribs[ValueNS].pop();
2607 fn with_label_rib<F>(&mut self, f: F)
2608 where F: FnOnce(&mut Resolver<'_>)
2610 self.label_ribs.push(Rib::new(NormalRibKind));
2612 self.label_ribs.pop();
2615 fn with_item_rib<F>(&mut self, f: F)
2616 where F: FnOnce(&mut Resolver<'_>)
2618 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2619 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2621 self.ribs[TypeNS].pop();
2622 self.ribs[ValueNS].pop();
2625 fn with_constant_rib<F>(&mut self, f: F)
2626 where F: FnOnce(&mut Resolver<'_>)
2628 debug!("with_constant_rib");
2629 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2630 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2632 self.label_ribs.pop();
2633 self.ribs[ValueNS].pop();
2636 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2637 where F: FnOnce(&mut Resolver<'_>) -> T
2639 // Handle nested impls (inside fn bodies)
2640 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2641 let result = f(self);
2642 self.current_self_type = previous_value;
2646 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2647 where F: FnOnce(&mut Resolver<'_>) -> T
2649 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2650 let result = f(self);
2651 self.current_self_item = previous_value;
2655 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
2656 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2657 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2659 let mut new_val = None;
2660 let mut new_id = None;
2661 if let Some(trait_ref) = opt_trait_ref {
2662 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2663 let def = self.smart_resolve_path_fragment(
2667 trait_ref.path.span,
2668 PathSource::Trait(AliasPossibility::No),
2669 CrateLint::SimplePath(trait_ref.ref_id),
2671 if def != Def::Err {
2672 new_id = Some(def.def_id());
2673 let span = trait_ref.path.span;
2674 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2675 self.resolve_path_without_parent_scope(
2680 CrateLint::SimplePath(trait_ref.ref_id),
2683 new_val = Some((module, trait_ref.clone()));
2687 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2688 let result = f(self, new_id);
2689 self.current_trait_ref = original_trait_ref;
2693 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2694 where F: FnOnce(&mut Resolver<'_>)
2696 let mut self_type_rib = Rib::new(NormalRibKind);
2698 // plain insert (no renaming, types are not currently hygienic....)
2699 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2700 self.ribs[TypeNS].push(self_type_rib);
2702 self.ribs[TypeNS].pop();
2705 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2706 where F: FnOnce(&mut Resolver<'_>)
2708 let self_def = Def::SelfCtor(impl_id);
2709 let mut self_type_rib = Rib::new(NormalRibKind);
2710 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2711 self.ribs[ValueNS].push(self_type_rib);
2713 self.ribs[ValueNS].pop();
2716 fn resolve_implementation(&mut self,
2717 generics: &Generics,
2718 opt_trait_reference: &Option<TraitRef>,
2721 impl_items: &[ImplItem]) {
2722 debug!("resolve_implementation");
2723 // If applicable, create a rib for the type parameters.
2724 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2725 // Dummy self type for better errors if `Self` is used in the trait path.
2726 this.with_self_rib(Def::SelfTy(None, None), |this| {
2727 // Resolve the trait reference, if necessary.
2728 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2729 let item_def_id = this.definitions.local_def_id(item_id);
2730 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2731 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2732 // Resolve type arguments in the trait path.
2733 visit::walk_trait_ref(this, trait_ref);
2735 // Resolve the self type.
2736 this.visit_ty(self_type);
2737 // Resolve the generic parameters.
2738 this.visit_generics(generics);
2739 // Resolve the items within the impl.
2740 this.with_current_self_type(self_type, |this| {
2741 this.with_self_struct_ctor_rib(item_def_id, |this| {
2742 debug!("resolve_implementation with_self_struct_ctor_rib");
2743 for impl_item in impl_items {
2744 this.resolve_visibility(&impl_item.vis);
2746 // We also need a new scope for the impl item type parameters.
2747 let generic_params = HasGenericParams(&impl_item.generics,
2748 TraitOrImplItemRibKind);
2749 this.with_generic_param_rib(generic_params, |this| {
2750 use self::ResolutionError::*;
2751 match impl_item.node {
2752 ImplItemKind::Const(..) => {
2754 "resolve_implementation ImplItemKind::Const",
2756 // If this is a trait impl, ensure the const
2758 this.check_trait_item(
2762 |n, s| ConstNotMemberOfTrait(n, s),
2765 this.with_constant_rib(|this| {
2766 visit::walk_impl_item(this, impl_item)
2769 ImplItemKind::Method(..) => {
2770 // If this is a trait impl, ensure the method
2772 this.check_trait_item(impl_item.ident,
2775 |n, s| MethodNotMemberOfTrait(n, s));
2777 visit::walk_impl_item(this, impl_item);
2779 ImplItemKind::Type(ref ty) => {
2780 // If this is a trait impl, ensure the type
2782 this.check_trait_item(impl_item.ident,
2785 |n, s| TypeNotMemberOfTrait(n, s));
2789 ImplItemKind::Existential(ref bounds) => {
2790 // If this is a trait impl, ensure the type
2792 this.check_trait_item(impl_item.ident,
2795 |n, s| TypeNotMemberOfTrait(n, s));
2797 for bound in bounds {
2798 this.visit_param_bound(bound);
2801 ImplItemKind::Macro(_) =>
2802 panic!("unexpanded macro in resolve!"),
2814 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2815 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2817 // If there is a TraitRef in scope for an impl, then the method must be in the
2819 if let Some((module, _)) = self.current_trait_ref {
2820 if self.resolve_ident_in_module(
2821 ModuleOrUniformRoot::Module(module),
2828 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2829 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2834 fn resolve_local(&mut self, local: &Local) {
2835 // Resolve the type.
2836 walk_list!(self, visit_ty, &local.ty);
2838 // Resolve the initializer.
2839 walk_list!(self, visit_expr, &local.init);
2841 // Resolve the pattern.
2842 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2845 // build a map from pattern identifiers to binding-info's.
2846 // this is done hygienically. This could arise for a macro
2847 // that expands into an or-pattern where one 'x' was from the
2848 // user and one 'x' came from the macro.
2849 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2850 let mut binding_map = FxHashMap::default();
2852 pat.walk(&mut |pat| {
2853 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2854 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2855 Some(Def::Local(..)) => true,
2858 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2859 binding_map.insert(ident, binding_info);
2868 // check that all of the arms in an or-pattern have exactly the
2869 // same set of bindings, with the same binding modes for each.
2870 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2871 if pats.is_empty() {
2875 let mut missing_vars = FxHashMap::default();
2876 let mut inconsistent_vars = FxHashMap::default();
2877 for (i, p) in pats.iter().enumerate() {
2878 let map_i = self.binding_mode_map(&p);
2880 for (j, q) in pats.iter().enumerate() {
2885 let map_j = self.binding_mode_map(&q);
2886 for (&key, &binding_i) in &map_i {
2887 if map_j.is_empty() { // Account for missing bindings when
2888 let binding_error = missing_vars // map_j has none.
2890 .or_insert(BindingError {
2892 origin: BTreeSet::new(),
2893 target: BTreeSet::new(),
2895 binding_error.origin.insert(binding_i.span);
2896 binding_error.target.insert(q.span);
2898 for (&key_j, &binding_j) in &map_j {
2899 match map_i.get(&key_j) {
2900 None => { // missing binding
2901 let binding_error = missing_vars
2903 .or_insert(BindingError {
2905 origin: BTreeSet::new(),
2906 target: BTreeSet::new(),
2908 binding_error.origin.insert(binding_j.span);
2909 binding_error.target.insert(p.span);
2911 Some(binding_i) => { // check consistent binding
2912 if binding_i.binding_mode != binding_j.binding_mode {
2915 .or_insert((binding_j.span, binding_i.span));
2923 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2924 missing_vars.sort();
2925 for (_, v) in missing_vars {
2927 *v.origin.iter().next().unwrap(),
2928 ResolutionError::VariableNotBoundInPattern(v));
2930 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2931 inconsistent_vars.sort();
2932 for (name, v) in inconsistent_vars {
2933 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2937 fn resolve_arm(&mut self, arm: &Arm) {
2938 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2940 let mut bindings_list = FxHashMap::default();
2941 for pattern in &arm.pats {
2942 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2945 // This has to happen *after* we determine which pat_idents are variants.
2946 self.check_consistent_bindings(&arm.pats);
2948 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2949 self.visit_expr(expr)
2951 self.visit_expr(&arm.body);
2953 self.ribs[ValueNS].pop();
2956 fn resolve_block(&mut self, block: &Block) {
2957 debug!("(resolving block) entering block");
2958 // Move down in the graph, if there's an anonymous module rooted here.
2959 let orig_module = self.current_module;
2960 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2962 let mut num_macro_definition_ribs = 0;
2963 if let Some(anonymous_module) = anonymous_module {
2964 debug!("(resolving block) found anonymous module, moving down");
2965 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2966 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2967 self.current_module = anonymous_module;
2968 self.finalize_current_module_macro_resolutions();
2970 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2973 // Descend into the block.
2974 for stmt in &block.stmts {
2975 if let ast::StmtKind::Item(ref item) = stmt.node {
2976 if let ast::ItemKind::MacroDef(..) = item.node {
2977 num_macro_definition_ribs += 1;
2978 let def = self.definitions.local_def_id(item.id);
2979 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2980 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2984 self.visit_stmt(stmt);
2988 self.current_module = orig_module;
2989 for _ in 0 .. num_macro_definition_ribs {
2990 self.ribs[ValueNS].pop();
2991 self.label_ribs.pop();
2993 self.ribs[ValueNS].pop();
2994 if anonymous_module.is_some() {
2995 self.ribs[TypeNS].pop();
2997 debug!("(resolving block) leaving block");
3000 fn fresh_binding(&mut self,
3003 outer_pat_id: NodeId,
3004 pat_src: PatternSource,
3005 bindings: &mut FxHashMap<Ident, NodeId>)
3007 // Add the binding to the local ribs, if it
3008 // doesn't already exist in the bindings map. (We
3009 // must not add it if it's in the bindings map
3010 // because that breaks the assumptions later
3011 // passes make about or-patterns.)
3012 let ident = ident.modern_and_legacy();
3013 let mut def = Def::Local(pat_id);
3014 match bindings.get(&ident).cloned() {
3015 Some(id) if id == outer_pat_id => {
3016 // `Variant(a, a)`, error
3020 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3024 Some(..) if pat_src == PatternSource::FnParam => {
3025 // `fn f(a: u8, a: u8)`, error
3029 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3033 Some(..) if pat_src == PatternSource::Match ||
3034 pat_src == PatternSource::IfLet ||
3035 pat_src == PatternSource::WhileLet => {
3036 // `Variant1(a) | Variant2(a)`, ok
3037 // Reuse definition from the first `a`.
3038 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3041 span_bug!(ident.span, "two bindings with the same name from \
3042 unexpected pattern source {:?}", pat_src);
3045 // A completely fresh binding, add to the lists if it's valid.
3046 if ident.name != keywords::Invalid.name() {
3047 bindings.insert(ident, outer_pat_id);
3048 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3053 PathResolution::new(def)
3056 fn resolve_pattern(&mut self,
3058 pat_src: PatternSource,
3059 // Maps idents to the node ID for the
3060 // outermost pattern that binds them.
3061 bindings: &mut FxHashMap<Ident, NodeId>) {
3062 // Visit all direct subpatterns of this pattern.
3063 let outer_pat_id = pat.id;
3064 pat.walk(&mut |pat| {
3065 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3067 PatKind::Ident(bmode, ident, ref opt_pat) => {
3068 // First try to resolve the identifier as some existing
3069 // entity, then fall back to a fresh binding.
3070 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3072 .and_then(LexicalScopeBinding::item);
3073 let resolution = binding.map(NameBinding::def).and_then(|def| {
3074 let is_syntactic_ambiguity = opt_pat.is_none() &&
3075 bmode == BindingMode::ByValue(Mutability::Immutable);
3077 Def::StructCtor(_, CtorKind::Const) |
3078 Def::VariantCtor(_, CtorKind::Const) |
3079 Def::Const(..) if is_syntactic_ambiguity => {
3080 // Disambiguate in favor of a unit struct/variant
3081 // or constant pattern.
3082 self.record_use(ident, ValueNS, binding.unwrap(), false);
3083 Some(PathResolution::new(def))
3085 Def::StructCtor(..) | Def::VariantCtor(..) |
3086 Def::Const(..) | Def::Static(..) => {
3087 // This is unambiguously a fresh binding, either syntactically
3088 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3089 // to something unusable as a pattern (e.g., constructor function),
3090 // but we still conservatively report an error, see
3091 // issues/33118#issuecomment-233962221 for one reason why.
3095 ResolutionError::BindingShadowsSomethingUnacceptable(
3096 pat_src.descr(), ident.name, binding.unwrap())
3100 Def::Fn(..) | Def::Err => {
3101 // These entities are explicitly allowed
3102 // to be shadowed by fresh bindings.
3106 span_bug!(ident.span, "unexpected definition for an \
3107 identifier in pattern: {:?}", def);
3110 }).unwrap_or_else(|| {
3111 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3114 self.record_def(pat.id, resolution);
3117 PatKind::TupleStruct(ref path, ..) => {
3118 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3121 PatKind::Path(ref qself, ref path) => {
3122 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3125 PatKind::Struct(ref path, ..) => {
3126 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3134 visit::walk_pat(self, pat);
3137 // High-level and context dependent path resolution routine.
3138 // Resolves the path and records the resolution into definition map.
3139 // If resolution fails tries several techniques to find likely
3140 // resolution candidates, suggest imports or other help, and report
3141 // errors in user friendly way.
3142 fn smart_resolve_path(&mut self,
3144 qself: Option<&QSelf>,
3146 source: PathSource<'_>)
3148 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3151 /// A variant of `smart_resolve_path` where you also specify extra
3152 /// information about where the path came from; this extra info is
3153 /// sometimes needed for the lint that recommends rewriting
3154 /// absolute paths to `crate`, so that it knows how to frame the
3155 /// suggestion. If you are just resolving a path like `foo::bar`
3156 /// that appears in an arbitrary location, then you just want
3157 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3158 /// already provides.
3159 fn smart_resolve_path_with_crate_lint(
3162 qself: Option<&QSelf>,
3164 source: PathSource<'_>,
3165 crate_lint: CrateLint
3166 ) -> PathResolution {
3167 self.smart_resolve_path_fragment(
3170 &Segment::from_path(path),
3177 fn smart_resolve_path_fragment(&mut self,
3179 qself: Option<&QSelf>,
3182 source: PathSource<'_>,
3183 crate_lint: CrateLint)
3185 let ns = source.namespace();
3186 let is_expected = &|def| source.is_expected(def);
3188 let report_errors = |this: &mut Self, def: Option<Def>| {
3189 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, def);
3190 let def_id = this.current_module.normal_ancestor_id;
3191 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3192 let better = def.is_some();
3193 this.use_injections.push(UseError { err, candidates, node_id, better });
3194 err_path_resolution()
3197 let resolution = match self.resolve_qpath_anywhere(
3203 source.defer_to_typeck(),
3204 source.global_by_default(),
3207 Some(resolution) if resolution.unresolved_segments() == 0 => {
3208 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3211 // Add a temporary hack to smooth the transition to new struct ctor
3212 // visibility rules. See #38932 for more details.
3214 if let Def::Struct(def_id) = resolution.base_def() {
3215 if let Some((ctor_def, ctor_vis))
3216 = self.struct_constructors.get(&def_id).cloned() {
3217 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3218 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3219 self.session.buffer_lint(lint, id, span,
3220 "private struct constructors are not usable through \
3221 re-exports in outer modules",
3223 res = Some(PathResolution::new(ctor_def));
3228 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3231 Some(resolution) if source.defer_to_typeck() => {
3232 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3233 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3234 // it needs to be added to the trait map.
3236 let item_name = path.last().unwrap().ident;
3237 let traits = self.get_traits_containing_item(item_name, ns);
3238 self.trait_map.insert(id, traits);
3242 _ => report_errors(self, None)
3245 if let PathSource::TraitItem(..) = source {} else {
3246 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3247 self.record_def(id, resolution);
3252 fn type_ascription_suggestion(&self,
3253 err: &mut DiagnosticBuilder<'_>,
3255 debug!("type_ascription_suggetion {:?}", base_span);
3256 let cm = self.session.source_map();
3257 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3258 if let Some(sp) = self.current_type_ascription.last() {
3261 // Try to find the `:`; bail on first non-':' / non-whitespace.
3262 sp = cm.next_point(sp);
3263 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3264 debug!("snippet {:?}", snippet);
3265 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3266 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3267 debug!("{:?} {:?}", line_sp, line_base_sp);
3269 err.span_label(base_span,
3270 "expecting a type here because of type ascription");
3271 if line_sp != line_base_sp {
3272 err.span_suggestion_short(
3274 "did you mean to use `;` here instead?",
3276 Applicability::MaybeIncorrect,
3280 } else if !snippet.trim().is_empty() {
3281 debug!("tried to find type ascription `:` token, couldn't find it");
3291 fn self_type_is_available(&mut self, span: Span) -> bool {
3292 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3293 TypeNS, None, span);
3294 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3297 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3298 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3299 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3300 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3303 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3304 fn resolve_qpath_anywhere(&mut self,
3306 qself: Option<&QSelf>,
3308 primary_ns: Namespace,
3310 defer_to_typeck: bool,
3311 global_by_default: bool,
3312 crate_lint: CrateLint)
3313 -> Option<PathResolution> {
3314 let mut fin_res = None;
3315 // FIXME: can't resolve paths in macro namespace yet, macros are
3316 // processed by the little special hack below.
3317 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3318 if i == 0 || ns != primary_ns {
3319 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3320 // If defer_to_typeck, then resolution > no resolution,
3321 // otherwise full resolution > partial resolution > no resolution.
3322 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3324 res => if fin_res.is_none() { fin_res = res },
3328 if primary_ns != MacroNS &&
3329 (self.macro_names.contains(&path[0].ident.modern()) ||
3330 self.builtin_macros.get(&path[0].ident.name).cloned()
3331 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3332 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3333 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3334 // Return some dummy definition, it's enough for error reporting.
3336 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3342 /// Handles paths that may refer to associated items.
3343 fn resolve_qpath(&mut self,
3345 qself: Option<&QSelf>,
3349 global_by_default: bool,
3350 crate_lint: CrateLint)
3351 -> Option<PathResolution> {
3353 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3354 ns={:?}, span={:?}, global_by_default={:?})",
3363 if let Some(qself) = qself {
3364 if qself.position == 0 {
3365 // This is a case like `<T>::B`, where there is no
3366 // trait to resolve. In that case, we leave the `B`
3367 // segment to be resolved by type-check.
3368 return Some(PathResolution::with_unresolved_segments(
3369 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3373 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3375 // Currently, `path` names the full item (`A::B::C`, in
3376 // our example). so we extract the prefix of that that is
3377 // the trait (the slice upto and including
3378 // `qself.position`). And then we recursively resolve that,
3379 // but with `qself` set to `None`.
3381 // However, setting `qself` to none (but not changing the
3382 // span) loses the information about where this path
3383 // *actually* appears, so for the purposes of the crate
3384 // lint we pass along information that this is the trait
3385 // name from a fully qualified path, and this also
3386 // contains the full span (the `CrateLint::QPathTrait`).
3387 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3388 let res = self.smart_resolve_path_fragment(
3391 &path[..=qself.position],
3393 PathSource::TraitItem(ns),
3394 CrateLint::QPathTrait {
3396 qpath_span: qself.path_span,
3400 // The remaining segments (the `C` in our example) will
3401 // have to be resolved by type-check, since that requires doing
3402 // trait resolution.
3403 return Some(PathResolution::with_unresolved_segments(
3404 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3408 let result = match self.resolve_path_without_parent_scope(
3415 PathResult::NonModule(path_res) => path_res,
3416 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3417 PathResolution::new(module.def().unwrap())
3419 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3420 // don't report an error right away, but try to fallback to a primitive type.
3421 // So, we are still able to successfully resolve something like
3423 // use std::u8; // bring module u8 in scope
3424 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3425 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3426 // // not to non-existent std::u8::max_value
3429 // Such behavior is required for backward compatibility.
3430 // The same fallback is used when `a` resolves to nothing.
3431 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3432 PathResult::Failed(..)
3433 if (ns == TypeNS || path.len() > 1) &&
3434 self.primitive_type_table.primitive_types
3435 .contains_key(&path[0].ident.name) => {
3436 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3437 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3439 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3440 PathResolution::new(module.def().unwrap()),
3441 PathResult::Failed(span, msg, false) => {
3442 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3443 err_path_resolution()
3445 PathResult::Module(..) | PathResult::Failed(..) => return None,
3446 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3449 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3450 path[0].ident.name != keywords::PathRoot.name() &&
3451 path[0].ident.name != keywords::DollarCrate.name() {
3452 let unqualified_result = {
3453 match self.resolve_path_without_parent_scope(
3454 &[*path.last().unwrap()],
3460 PathResult::NonModule(path_res) => path_res.base_def(),
3461 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3462 module.def().unwrap(),
3463 _ => return Some(result),
3466 if result.base_def() == unqualified_result {
3467 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3468 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3475 fn resolve_path_without_parent_scope(
3478 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3481 crate_lint: CrateLint,
3482 ) -> PathResult<'a> {
3483 // Macro and import paths must have full parent scope available during resolution,
3484 // other paths will do okay with parent module alone.
3485 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3486 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3487 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3493 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3494 parent_scope: &ParentScope<'a>,
3497 crate_lint: CrateLint,
3498 ) -> PathResult<'a> {
3499 let mut module = None;
3500 let mut allow_super = true;
3501 let mut second_binding = None;
3502 self.current_module = parent_scope.module;
3505 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3506 path_span={:?}, crate_lint={:?})",
3514 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3515 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3516 let record_segment_def = |this: &mut Self, def| {
3518 if let Some(id) = id {
3519 if !this.def_map.contains_key(&id) {
3520 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3521 this.record_def(id, PathResolution::new(def));
3527 let is_last = i == path.len() - 1;
3528 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3529 let name = ident.name;
3531 allow_super &= ns == TypeNS &&
3532 (name == keywords::SelfLower.name() ||
3533 name == keywords::Super.name());
3536 if allow_super && name == keywords::Super.name() {
3537 let mut ctxt = ident.span.ctxt().modern();
3538 let self_module = match i {
3539 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3541 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3545 if let Some(self_module) = self_module {
3546 if let Some(parent) = self_module.parent {
3547 module = Some(ModuleOrUniformRoot::Module(
3548 self.resolve_self(&mut ctxt, parent)));
3552 let msg = "there are too many initial `super`s.".to_string();
3553 return PathResult::Failed(ident.span, msg, false);
3556 if name == keywords::SelfLower.name() {
3557 let mut ctxt = ident.span.ctxt().modern();
3558 module = Some(ModuleOrUniformRoot::Module(
3559 self.resolve_self(&mut ctxt, self.current_module)));
3562 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3563 module = Some(ModuleOrUniformRoot::ExternPrelude);
3566 if name == keywords::PathRoot.name() &&
3567 ident.span.rust_2015() && self.session.rust_2018() {
3568 // `::a::b` from 2015 macro on 2018 global edition
3569 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3572 if name == keywords::PathRoot.name() ||
3573 name == keywords::Crate.name() ||
3574 name == keywords::DollarCrate.name() {
3575 // `::a::b`, `crate::a::b` or `$crate::a::b`
3576 module = Some(ModuleOrUniformRoot::Module(
3577 self.resolve_crate_root(ident)));
3583 // Report special messages for path segment keywords in wrong positions.
3584 if ident.is_path_segment_keyword() && i != 0 {
3585 let name_str = if name == keywords::PathRoot.name() {
3586 "crate root".to_string()
3588 format!("`{}`", name)
3590 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3591 format!("global paths cannot start with {}", name_str)
3593 format!("{} in paths can only be used in start position", name_str)
3595 return PathResult::Failed(ident.span, msg, false);
3598 let binding = if let Some(module) = module {
3599 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3600 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3601 assert!(ns == TypeNS);
3602 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3603 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3604 record_used, path_span)
3606 let record_used_id =
3607 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3608 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3609 // we found a locally-imported or available item/module
3610 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3611 // we found a local variable or type param
3612 Some(LexicalScopeBinding::Def(def))
3613 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3614 record_segment_def(self, def);
3615 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3619 _ => Err(Determinacy::determined(record_used)),
3626 second_binding = Some(binding);
3628 let def = binding.def();
3629 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3630 if let Some(next_module) = binding.module() {
3631 module = Some(ModuleOrUniformRoot::Module(next_module));
3632 record_segment_def(self, def);
3633 } else if def == Def::ToolMod && i + 1 != path.len() {
3634 if binding.is_import() {
3635 self.session.struct_span_err(
3636 ident.span, "cannot use a tool module through an import"
3638 binding.span, "the tool module imported here"
3641 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3642 return PathResult::NonModule(PathResolution::new(def));
3643 } else if def == Def::Err {
3644 return PathResult::NonModule(err_path_resolution());
3645 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3646 self.lint_if_path_starts_with_module(
3652 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3653 def, path.len() - i - 1
3656 return PathResult::Failed(ident.span,
3657 format!("not a module `{}`", ident),
3661 Err(Undetermined) => return PathResult::Indeterminate,
3662 Err(Determined) => {
3663 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3664 if opt_ns.is_some() && !module.is_normal() {
3665 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3666 module.def().unwrap(), path.len() - i
3670 let module_def = match module {
3671 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3674 let msg = if module_def == self.graph_root.def() {
3675 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3676 let mut candidates =
3677 self.lookup_import_candidates(ident, TypeNS, is_mod);
3678 candidates.sort_by_cached_key(|c| {
3679 (c.path.segments.len(), c.path.to_string())
3681 if let Some(candidate) = candidates.get(0) {
3682 format!("did you mean `{}`?", candidate.path)
3683 } else if !ident.is_reserved() {
3684 format!("maybe a missing `extern crate {};`?", ident)
3686 // the parser will already have complained about the keyword being used
3687 return PathResult::NonModule(err_path_resolution());
3690 format!("use of undeclared type or module `{}`", ident)
3692 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
3694 return PathResult::Failed(ident.span, msg, is_last);
3699 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3701 PathResult::Module(match module {
3702 Some(module) => module,
3703 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3704 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3708 fn lint_if_path_starts_with_module(
3710 crate_lint: CrateLint,
3713 second_binding: Option<&NameBinding<'_>>,
3715 let (diag_id, diag_span) = match crate_lint {
3716 CrateLint::No => return,
3717 CrateLint::SimplePath(id) => (id, path_span),
3718 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3719 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3722 let first_name = match path.get(0) {
3723 // In the 2018 edition this lint is a hard error, so nothing to do
3724 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3728 // We're only interested in `use` paths which should start with
3729 // `{{root}}` currently.
3730 if first_name != keywords::PathRoot.name() {
3735 // If this import looks like `crate::...` it's already good
3736 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3737 // Otherwise go below to see if it's an extern crate
3739 // If the path has length one (and it's `PathRoot` most likely)
3740 // then we don't know whether we're gonna be importing a crate or an
3741 // item in our crate. Defer this lint to elsewhere
3745 // If the first element of our path was actually resolved to an
3746 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3747 // warning, this looks all good!
3748 if let Some(binding) = second_binding {
3749 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3750 // Careful: we still want to rewrite paths from
3751 // renamed extern crates.
3752 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3758 let diag = lint::builtin::BuiltinLintDiagnostics
3759 ::AbsPathWithModule(diag_span);
3760 self.session.buffer_lint_with_diagnostic(
3761 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3763 "absolute paths must start with `self`, `super`, \
3764 `crate`, or an external crate name in the 2018 edition",
3768 // Resolve a local definition, potentially adjusting for closures.
3769 fn adjust_local_def(&mut self,
3774 span: Span) -> Def {
3775 debug!("adjust_local_def");
3776 let ribs = &self.ribs[ns][rib_index + 1..];
3778 // An invalid forward use of a type parameter from a previous default.
3779 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3781 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3783 assert_eq!(def, Def::Err);
3789 span_bug!(span, "unexpected {:?} in bindings", def)
3791 Def::Local(node_id) => {
3792 use ResolutionError::*;
3793 let mut res_err = None;
3797 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3798 ForwardTyParamBanRibKind => {
3799 // Nothing to do. Continue.
3801 ClosureRibKind(function_id) => {
3804 let seen = self.freevars_seen
3807 if let Some(&index) = seen.get(&node_id) {
3808 def = Def::Upvar(node_id, index, function_id);
3811 let vec = self.freevars
3814 let depth = vec.len();
3815 def = Def::Upvar(node_id, depth, function_id);
3822 seen.insert(node_id, depth);
3825 ItemRibKind | TraitOrImplItemRibKind => {
3826 // This was an attempt to access an upvar inside a
3827 // named function item. This is not allowed, so we
3830 // We don't immediately trigger a resolve error, because
3831 // we want certain other resolution errors (namely those
3832 // emitted for `ConstantItemRibKind` below) to take
3834 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
3837 ConstantItemRibKind => {
3838 // Still doesn't deal with upvars
3840 resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
3846 if let Some(res_err) = res_err {
3847 resolve_error(self, span, res_err);
3851 Def::TyParam(..) | Def::SelfTy(..) => {
3854 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3855 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3856 ConstantItemRibKind => {
3857 // Nothing to do. Continue.
3860 // This was an attempt to use a type parameter outside its scope.
3865 ResolutionError::GenericParamsFromOuterFunction(def),
3873 Def::ConstParam(..) => {
3874 // A const param is always declared in a signature, which is always followed by
3875 // some kind of function rib kind (specifically, ItemRibKind in the case of a
3876 // normal function), so we can skip the first rib as it will be guaranteed to
3877 // (spuriously) conflict with the const param.
3878 for rib in &ribs[1..] {
3879 if let ItemRibKind = rib.kind {
3880 // This was an attempt to use a const parameter outside its scope.
3885 ResolutionError::GenericParamsFromOuterFunction(def),
3897 fn lookup_assoc_candidate<FilterFn>(&mut self,
3900 filter_fn: FilterFn)
3901 -> Option<AssocSuggestion>
3902 where FilterFn: Fn(Def) -> bool
3904 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3906 TyKind::Path(None, _) => Some(t.id),
3907 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3908 // This doesn't handle the remaining `Ty` variants as they are not
3909 // that commonly the self_type, it might be interesting to provide
3910 // support for those in future.
3915 // Fields are generally expected in the same contexts as locals.
3916 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3917 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3918 // Look for a field with the same name in the current self_type.
3919 if let Some(resolution) = self.def_map.get(&node_id) {
3920 match resolution.base_def() {
3921 Def::Struct(did) | Def::Union(did)
3922 if resolution.unresolved_segments() == 0 => {
3923 if let Some(field_names) = self.field_names.get(&did) {
3924 if field_names.iter().any(|&field_name| ident.name == field_name) {
3925 return Some(AssocSuggestion::Field);
3935 // Look for associated items in the current trait.
3936 if let Some((module, _)) = self.current_trait_ref {
3937 if let Ok(binding) = self.resolve_ident_in_module(
3938 ModuleOrUniformRoot::Module(module),
3945 let def = binding.def();
3947 return Some(if self.has_self.contains(&def.def_id()) {
3948 AssocSuggestion::MethodWithSelf
3950 AssocSuggestion::AssocItem
3959 fn lookup_typo_candidate<FilterFn>(
3963 filter_fn: FilterFn,
3965 ) -> Option<TypoSuggestion>
3967 FilterFn: Fn(Def) -> bool,
3969 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
3970 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3971 if let Some(binding) = resolution.borrow().binding {
3972 if filter_fn(binding.def()) {
3973 names.push(TypoSuggestion {
3974 candidate: ident.name,
3975 article: binding.def().article(),
3976 kind: binding.def().kind_name(),
3983 let mut names = Vec::new();
3984 if path.len() == 1 {
3985 // Search in lexical scope.
3986 // Walk backwards up the ribs in scope and collect candidates.
3987 for rib in self.ribs[ns].iter().rev() {
3988 // Locals and type parameters
3989 for (ident, def) in &rib.bindings {
3990 if filter_fn(*def) {
3991 names.push(TypoSuggestion {
3992 candidate: ident.name,
3993 article: def.article(),
3994 kind: def.kind_name(),
3999 if let ModuleRibKind(module) = rib.kind {
4000 // Items from this module
4001 add_module_candidates(module, &mut names);
4003 if let ModuleKind::Block(..) = module.kind {
4004 // We can see through blocks
4006 // Items from the prelude
4007 if !module.no_implicit_prelude {
4008 names.extend(self.extern_prelude.iter().map(|(ident, _)| {
4010 candidate: ident.name,
4015 if let Some(prelude) = self.prelude {
4016 add_module_candidates(prelude, &mut names);
4023 // Add primitive types to the mix
4024 if filter_fn(Def::PrimTy(Bool)) {
4026 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4030 kind: "primitive type",
4036 // Search in module.
4037 let mod_path = &path[..path.len() - 1];
4038 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4039 mod_path, Some(TypeNS), false, span, CrateLint::No
4041 if let ModuleOrUniformRoot::Module(module) = module {
4042 add_module_candidates(module, &mut names);
4047 let name = path[path.len() - 1].ident.name;
4048 // Make sure error reporting is deterministic.
4049 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4051 match find_best_match_for_name(
4052 names.iter().map(|suggestion| &suggestion.candidate),
4056 Some(found) if found != name => names
4058 .find(|suggestion| suggestion.candidate == found),
4063 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4064 where F: FnOnce(&mut Resolver<'_>)
4066 if let Some(label) = label {
4067 self.unused_labels.insert(id, label.ident.span);
4068 let def = Def::Label(id);
4069 self.with_label_rib(|this| {
4070 let ident = label.ident.modern_and_legacy();
4071 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4079 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4080 self.with_resolved_label(label, id, |this| this.visit_block(block));
4083 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4084 // First, record candidate traits for this expression if it could
4085 // result in the invocation of a method call.
4087 self.record_candidate_traits_for_expr_if_necessary(expr);
4089 // Next, resolve the node.
4091 ExprKind::Path(ref qself, ref path) => {
4092 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4093 visit::walk_expr(self, expr);
4096 ExprKind::Struct(ref path, ..) => {
4097 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4098 visit::walk_expr(self, expr);
4101 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4102 let def = self.search_label(label.ident, |rib, ident| {
4103 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4107 // Search again for close matches...
4108 // Picks the first label that is "close enough", which is not necessarily
4109 // the closest match
4110 let close_match = self.search_label(label.ident, |rib, ident| {
4111 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4112 find_best_match_for_name(names, &*ident.as_str(), None)
4114 self.record_def(expr.id, err_path_resolution());
4117 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4120 Some(Def::Label(id)) => {
4121 // Since this def is a label, it is never read.
4122 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4123 self.unused_labels.remove(&id);
4126 span_bug!(expr.span, "label wasn't mapped to a label def!");
4130 // visit `break` argument if any
4131 visit::walk_expr(self, expr);
4134 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4135 self.visit_expr(subexpression);
4137 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4138 let mut bindings_list = FxHashMap::default();
4140 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4142 // This has to happen *after* we determine which pat_idents are variants
4143 self.check_consistent_bindings(pats);
4144 self.visit_block(if_block);
4145 self.ribs[ValueNS].pop();
4147 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4150 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4152 ExprKind::While(ref subexpression, ref block, label) => {
4153 self.with_resolved_label(label, expr.id, |this| {
4154 this.visit_expr(subexpression);
4155 this.visit_block(block);
4159 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4160 self.with_resolved_label(label, expr.id, |this| {
4161 this.visit_expr(subexpression);
4162 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4163 let mut bindings_list = FxHashMap::default();
4165 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4167 // This has to happen *after* we determine which pat_idents are variants.
4168 this.check_consistent_bindings(pats);
4169 this.visit_block(block);
4170 this.ribs[ValueNS].pop();
4174 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4175 self.visit_expr(subexpression);
4176 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4177 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4179 self.resolve_labeled_block(label, expr.id, block);
4181 self.ribs[ValueNS].pop();
4184 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4186 // Equivalent to `visit::walk_expr` + passing some context to children.
4187 ExprKind::Field(ref subexpression, _) => {
4188 self.resolve_expr(subexpression, Some(expr));
4190 ExprKind::MethodCall(ref segment, ref arguments) => {
4191 let mut arguments = arguments.iter();
4192 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4193 for argument in arguments {
4194 self.resolve_expr(argument, None);
4196 self.visit_path_segment(expr.span, segment);
4199 ExprKind::Call(ref callee, ref arguments) => {
4200 self.resolve_expr(callee, Some(expr));
4201 for argument in arguments {
4202 self.resolve_expr(argument, None);
4205 ExprKind::Type(ref type_expr, _) => {
4206 self.current_type_ascription.push(type_expr.span);
4207 visit::walk_expr(self, expr);
4208 self.current_type_ascription.pop();
4210 // Resolve the body of async exprs inside the async closure to which they desugar
4211 ExprKind::Async(_, async_closure_id, ref block) => {
4212 let rib_kind = ClosureRibKind(async_closure_id);
4213 self.ribs[ValueNS].push(Rib::new(rib_kind));
4214 self.label_ribs.push(Rib::new(rib_kind));
4215 self.visit_block(&block);
4216 self.label_ribs.pop();
4217 self.ribs[ValueNS].pop();
4219 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4220 // resolve the arguments within the proper scopes so that usages of them inside the
4221 // closure are detected as upvars rather than normal closure arg usages.
4223 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4224 ref fn_decl, ref body, _span,
4226 let rib_kind = ClosureRibKind(expr.id);
4227 self.ribs[ValueNS].push(Rib::new(rib_kind));
4228 self.label_ribs.push(Rib::new(rib_kind));
4229 // Resolve arguments:
4230 let mut bindings_list = FxHashMap::default();
4231 for argument in &fn_decl.inputs {
4232 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4233 self.visit_ty(&argument.ty);
4235 // No need to resolve return type-- the outer closure return type is
4236 // FunctionRetTy::Default
4238 // Now resolve the inner closure
4240 let rib_kind = ClosureRibKind(inner_closure_id);
4241 self.ribs[ValueNS].push(Rib::new(rib_kind));
4242 self.label_ribs.push(Rib::new(rib_kind));
4243 // No need to resolve arguments: the inner closure has none.
4244 // Resolve the return type:
4245 visit::walk_fn_ret_ty(self, &fn_decl.output);
4247 self.visit_expr(body);
4248 self.label_ribs.pop();
4249 self.ribs[ValueNS].pop();
4251 self.label_ribs.pop();
4252 self.ribs[ValueNS].pop();
4255 visit::walk_expr(self, expr);
4260 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4262 ExprKind::Field(_, ident) => {
4263 // FIXME(#6890): Even though you can't treat a method like a
4264 // field, we need to add any trait methods we find that match
4265 // the field name so that we can do some nice error reporting
4266 // later on in typeck.
4267 let traits = self.get_traits_containing_item(ident, ValueNS);
4268 self.trait_map.insert(expr.id, traits);
4270 ExprKind::MethodCall(ref segment, ..) => {
4271 debug!("(recording candidate traits for expr) recording traits for {}",
4273 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4274 self.trait_map.insert(expr.id, traits);
4282 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4283 -> Vec<TraitCandidate> {
4284 debug!("(getting traits containing item) looking for '{}'", ident.name);
4286 let mut found_traits = Vec::new();
4287 // Look for the current trait.
4288 if let Some((module, _)) = self.current_trait_ref {
4289 if self.resolve_ident_in_module(
4290 ModuleOrUniformRoot::Module(module),
4297 let def_id = module.def_id().unwrap();
4298 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4302 ident.span = ident.span.modern();
4303 let mut search_module = self.current_module;
4305 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4306 search_module = unwrap_or!(
4307 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4311 if let Some(prelude) = self.prelude {
4312 if !search_module.no_implicit_prelude {
4313 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4320 fn get_traits_in_module_containing_item(&mut self,
4324 found_traits: &mut Vec<TraitCandidate>) {
4325 assert!(ns == TypeNS || ns == ValueNS);
4326 let mut traits = module.traits.borrow_mut();
4327 if traits.is_none() {
4328 let mut collected_traits = Vec::new();
4329 module.for_each_child(|name, ns, binding| {
4330 if ns != TypeNS { return }
4331 if let Def::Trait(_) = binding.def() {
4332 collected_traits.push((name, binding));
4335 *traits = Some(collected_traits.into_boxed_slice());
4338 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4339 let module = binding.module().unwrap();
4340 let mut ident = ident;
4341 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4344 if self.resolve_ident_in_module_unadjusted(
4345 ModuleOrUniformRoot::Module(module),
4351 let import_id = match binding.kind {
4352 NameBindingKind::Import { directive, .. } => {
4353 self.maybe_unused_trait_imports.insert(directive.id);
4354 self.add_to_glob_map(&directive, trait_name);
4359 let trait_def_id = module.def_id().unwrap();
4360 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4365 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4366 lookup_ident: Ident,
4367 namespace: Namespace,
4368 start_module: &'a ModuleData<'a>,
4370 filter_fn: FilterFn)
4371 -> Vec<ImportSuggestion>
4372 where FilterFn: Fn(Def) -> bool
4374 let mut candidates = Vec::new();
4375 let mut seen_modules = FxHashSet::default();
4376 let not_local_module = crate_name != keywords::Crate.ident();
4377 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4379 while let Some((in_module,
4381 in_module_is_extern)) = worklist.pop() {
4382 self.populate_module_if_necessary(in_module);
4384 // We have to visit module children in deterministic order to avoid
4385 // instabilities in reported imports (#43552).
4386 in_module.for_each_child_stable(|ident, ns, name_binding| {
4387 // avoid imports entirely
4388 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4389 // avoid non-importable candidates as well
4390 if !name_binding.is_importable() { return; }
4392 // collect results based on the filter function
4393 if ident.name == lookup_ident.name && ns == namespace {
4394 let def = name_binding.def();
4397 let mut segms = path_segments.clone();
4398 if lookup_ident.span.rust_2018() {
4399 // crate-local absolute paths start with `crate::` in edition 2018
4400 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4402 0, ast::PathSegment::from_ident(crate_name)
4406 segms.push(ast::PathSegment::from_ident(ident));
4408 span: name_binding.span,
4411 // the entity is accessible in the following cases:
4412 // 1. if it's defined in the same crate, it's always
4413 // accessible (since private entities can be made public)
4414 // 2. if it's defined in another crate, it's accessible
4415 // only if both the module is public and the entity is
4416 // declared as public (due to pruning, we don't explore
4417 // outside crate private modules => no need to check this)
4418 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4419 let did = match def {
4420 Def::StructCtor(did, _) | Def::VariantCtor(did, _) =>
4422 _ => def.opt_def_id(),
4424 candidates.push(ImportSuggestion { did, path });
4429 // collect submodules to explore
4430 if let Some(module) = name_binding.module() {
4432 let mut path_segments = path_segments.clone();
4433 path_segments.push(ast::PathSegment::from_ident(ident));
4435 let is_extern_crate_that_also_appears_in_prelude =
4436 name_binding.is_extern_crate() &&
4437 lookup_ident.span.rust_2018();
4439 let is_visible_to_user =
4440 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4442 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4443 // add the module to the lookup
4444 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4445 if seen_modules.insert(module.def_id().unwrap()) {
4446 worklist.push((module, path_segments, is_extern));
4456 /// When name resolution fails, this method can be used to look up candidate
4457 /// entities with the expected name. It allows filtering them using the
4458 /// supplied predicate (which should be used to only accept the types of
4459 /// definitions expected, e.g., traits). The lookup spans across all crates.
4461 /// N.B., the method does not look into imports, but this is not a problem,
4462 /// since we report the definitions (thus, the de-aliased imports).
4463 fn lookup_import_candidates<FilterFn>(&mut self,
4464 lookup_ident: Ident,
4465 namespace: Namespace,
4466 filter_fn: FilterFn)
4467 -> Vec<ImportSuggestion>
4468 where FilterFn: Fn(Def) -> bool
4470 let mut suggestions = self.lookup_import_candidates_from_module(
4471 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4473 if lookup_ident.span.rust_2018() {
4474 let extern_prelude_names = self.extern_prelude.clone();
4475 for (ident, _) in extern_prelude_names.into_iter() {
4476 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4478 let crate_root = self.get_module(DefId {
4480 index: CRATE_DEF_INDEX,
4482 self.populate_module_if_necessary(&crate_root);
4484 suggestions.extend(self.lookup_import_candidates_from_module(
4485 lookup_ident, namespace, crate_root, ident, &filter_fn));
4493 fn find_module(&mut self,
4495 -> Option<(Module<'a>, ImportSuggestion)>
4497 let mut result = None;
4498 let mut seen_modules = FxHashSet::default();
4499 let mut worklist = vec![(self.graph_root, Vec::new())];
4501 while let Some((in_module, path_segments)) = worklist.pop() {
4502 // abort if the module is already found
4503 if result.is_some() { break; }
4505 self.populate_module_if_necessary(in_module);
4507 in_module.for_each_child_stable(|ident, _, name_binding| {
4508 // abort if the module is already found or if name_binding is private external
4509 if result.is_some() || !name_binding.vis.is_visible_locally() {
4512 if let Some(module) = name_binding.module() {
4514 let mut path_segments = path_segments.clone();
4515 path_segments.push(ast::PathSegment::from_ident(ident));
4516 if module.def() == Some(module_def) {
4518 span: name_binding.span,
4519 segments: path_segments,
4521 let did = module.def().and_then(|def| def.opt_def_id());
4522 result = Some((module, ImportSuggestion { did, path }));
4524 // add the module to the lookup
4525 if seen_modules.insert(module.def_id().unwrap()) {
4526 worklist.push((module, path_segments));
4536 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4537 if let Def::Enum(..) = enum_def {} else {
4538 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4541 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4542 self.populate_module_if_necessary(enum_module);
4544 let mut variants = Vec::new();
4545 enum_module.for_each_child_stable(|ident, _, name_binding| {
4546 if let Def::Variant(..) = name_binding.def() {
4547 let mut segms = enum_import_suggestion.path.segments.clone();
4548 segms.push(ast::PathSegment::from_ident(ident));
4549 variants.push(Path {
4550 span: name_binding.span,
4559 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4560 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4561 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4562 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4566 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4568 ast::VisibilityKind::Public => ty::Visibility::Public,
4569 ast::VisibilityKind::Crate(..) => {
4570 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4572 ast::VisibilityKind::Inherited => {
4573 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4575 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4576 // For visibilities we are not ready to provide correct implementation of "uniform
4577 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4578 // On 2015 edition visibilities are resolved as crate-relative by default,
4579 // so we are prepending a root segment if necessary.
4580 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4581 let crate_root = if ident.is_path_segment_keyword() {
4583 } else if ident.span.rust_2018() {
4584 let msg = "relative paths are not supported in visibilities on 2018 edition";
4585 self.session.struct_span_err(ident.span, msg)
4589 format!("crate::{}", path),
4590 Applicability::MaybeIncorrect,
4593 return ty::Visibility::Public;
4595 let ctxt = ident.span.ctxt();
4596 Some(Segment::from_ident(Ident::new(
4597 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4601 let segments = crate_root.into_iter()
4602 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4603 let def = self.smart_resolve_path_fragment(
4608 PathSource::Visibility,
4609 CrateLint::SimplePath(id),
4611 if def == Def::Err {
4612 ty::Visibility::Public
4614 let vis = ty::Visibility::Restricted(def.def_id());
4615 if self.is_accessible(vis) {
4618 self.session.span_err(path.span, "visibilities can only be restricted \
4619 to ancestor modules");
4620 ty::Visibility::Public
4627 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4628 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4631 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4632 vis.is_accessible_from(module.normal_ancestor_id, self)
4635 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4636 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4637 if !ptr::eq(module, old_module) {
4638 span_bug!(binding.span, "parent module is reset for binding");
4643 fn disambiguate_legacy_vs_modern(
4645 legacy: &'a NameBinding<'a>,
4646 modern: &'a NameBinding<'a>,
4648 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4649 // is disambiguated to mitigate regressions from macro modularization.
4650 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4651 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4652 self.binding_parent_modules.get(&PtrKey(modern))) {
4653 (Some(legacy), Some(modern)) =>
4654 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4655 modern.is_ancestor_of(legacy),
4660 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
4661 if b.span.is_dummy() {
4662 let add_built_in = match b.def() {
4663 // These already contain the "built-in" prefix or look bad with it.
4664 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4667 let (built_in, from) = if from_prelude {
4668 ("", " from prelude")
4669 } else if b.is_extern_crate() && !b.is_import() &&
4670 self.session.opts.externs.get(&ident.as_str()).is_some() {
4671 ("", " passed with `--extern`")
4672 } else if add_built_in {
4678 let article = if built_in.is_empty() { b.article() } else { "a" };
4679 format!("{a}{built_in} {thing}{from}",
4680 a = article, thing = b.descr(), built_in = built_in, from = from)
4682 let introduced = if b.is_import() { "imported" } else { "defined" };
4683 format!("the {thing} {introduced} here",
4684 thing = b.descr(), introduced = introduced)
4688 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
4689 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4690 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4691 // We have to print the span-less alternative first, otherwise formatting looks bad.
4692 (b2, b1, misc2, misc1, true)
4694 (b1, b2, misc1, misc2, false)
4697 let mut err = struct_span_err!(self.session, ident.span, E0659,
4698 "`{ident}` is ambiguous ({why})",
4699 ident = ident, why = kind.descr());
4700 err.span_label(ident.span, "ambiguous name");
4702 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
4703 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4704 let note_msg = format!("`{ident}` could{also} refer to {what}",
4705 ident = ident, also = also, what = what);
4707 let mut help_msgs = Vec::new();
4708 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4709 kind == AmbiguityKind::GlobVsExpanded ||
4710 kind == AmbiguityKind::GlobVsOuter &&
4711 swapped != also.is_empty()) {
4712 help_msgs.push(format!("consider adding an explicit import of \
4713 `{ident}` to disambiguate", ident = ident))
4715 if b.is_extern_crate() && ident.span.rust_2018() {
4716 help_msgs.push(format!(
4717 "use `::{ident}` to refer to this {thing} unambiguously",
4718 ident = ident, thing = b.descr(),
4721 if misc == AmbiguityErrorMisc::SuggestCrate {
4722 help_msgs.push(format!(
4723 "use `crate::{ident}` to refer to this {thing} unambiguously",
4724 ident = ident, thing = b.descr(),
4726 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4727 help_msgs.push(format!(
4728 "use `self::{ident}` to refer to this {thing} unambiguously",
4729 ident = ident, thing = b.descr(),
4733 err.span_note(b.span, ¬e_msg);
4734 for (i, help_msg) in help_msgs.iter().enumerate() {
4735 let or = if i == 0 { "" } else { "or " };
4736 err.help(&format!("{}{}", or, help_msg));
4740 could_refer_to(b1, misc1, "");
4741 could_refer_to(b2, misc2, " also");
4745 fn report_errors(&mut self, krate: &Crate) {
4746 self.report_with_use_injections(krate);
4748 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4749 let msg = "macro-expanded `macro_export` macros from the current crate \
4750 cannot be referred to by absolute paths";
4751 self.session.buffer_lint_with_diagnostic(
4752 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4753 CRATE_NODE_ID, span_use, msg,
4754 lint::builtin::BuiltinLintDiagnostics::
4755 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4759 for ambiguity_error in &self.ambiguity_errors {
4760 self.report_ambiguity_error(ambiguity_error);
4763 let mut reported_spans = FxHashSet::default();
4764 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4765 if reported_spans.insert(dedup_span) {
4766 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4767 binding.descr(), ident.name);
4772 fn report_with_use_injections(&mut self, krate: &Crate) {
4773 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4774 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4775 if !candidates.is_empty() {
4776 show_candidates(&mut err, span, &candidates, better, found_use);
4782 fn report_conflict<'b>(&mut self,
4786 new_binding: &NameBinding<'b>,
4787 old_binding: &NameBinding<'b>) {
4788 // Error on the second of two conflicting names
4789 if old_binding.span.lo() > new_binding.span.lo() {
4790 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4793 let container = match parent.kind {
4794 ModuleKind::Def(Def::Mod(_), _) => "module",
4795 ModuleKind::Def(Def::Trait(_), _) => "trait",
4796 ModuleKind::Block(..) => "block",
4800 let old_noun = match old_binding.is_import() {
4802 false => "definition",
4805 let new_participle = match new_binding.is_import() {
4810 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4812 if let Some(s) = self.name_already_seen.get(&name) {
4818 let old_kind = match (ns, old_binding.module()) {
4819 (ValueNS, _) => "value",
4820 (MacroNS, _) => "macro",
4821 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4822 (TypeNS, Some(module)) if module.is_normal() => "module",
4823 (TypeNS, Some(module)) if module.is_trait() => "trait",
4824 (TypeNS, _) => "type",
4827 let msg = format!("the name `{}` is defined multiple times", name);
4829 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4830 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4831 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4832 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4833 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4835 _ => match (old_binding.is_import(), new_binding.is_import()) {
4836 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4837 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4838 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4842 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4847 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4849 self.session.source_map().def_span(old_binding.span),
4850 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
4853 // See https://github.com/rust-lang/rust/issues/32354
4854 use NameBindingKind::Import;
4855 let directive = match (&new_binding.kind, &old_binding.kind) {
4856 // If there are two imports where one or both have attributes then prefer removing the
4857 // import without attributes.
4858 (Import { directive: new, .. }, Import { directive: old, .. }) if {
4859 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
4860 (new.has_attributes || old.has_attributes)
4862 if old.has_attributes {
4863 Some((new, new_binding.span, true))
4865 Some((old, old_binding.span, true))
4868 // Otherwise prioritize the new binding.
4869 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
4870 Some((directive, new_binding.span, other.is_import())),
4871 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
4872 Some((directive, old_binding.span, other.is_import())),
4876 // Check if the target of the use for both bindings is the same.
4877 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
4878 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
4879 let from_item = self.extern_prelude.get(&ident)
4880 .map(|entry| entry.introduced_by_item)
4882 // Only suggest removing an import if both bindings are to the same def, if both spans
4883 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
4884 // been introduced by a item.
4885 let should_remove_import = duplicate && !has_dummy_span &&
4886 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
4889 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
4890 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
4891 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
4892 // Simple case - remove the entire import. Due to the above match arm, this can
4893 // only be a single use so just remove it entirely.
4894 err.span_suggestion(
4895 directive.use_span_with_attributes,
4896 "remove unnecessary import",
4898 Applicability::MaybeIncorrect,
4901 Some((directive, span, _)) =>
4902 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
4907 self.name_already_seen.insert(name, span);
4910 /// This function adds a suggestion to change the binding name of a new import that conflicts
4911 /// with an existing import.
4913 /// ```ignore (diagnostic)
4914 /// help: you can use `as` to change the binding name of the import
4916 /// LL | use foo::bar as other_bar;
4917 /// | ^^^^^^^^^^^^^^^^^^^^^
4919 fn add_suggestion_for_rename_of_use(
4921 err: &mut DiagnosticBuilder<'_>,
4923 directive: &ImportDirective<'_>,
4926 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4927 format!("Other{}", name)
4929 format!("other_{}", name)
4932 let mut suggestion = None;
4933 match directive.subclass {
4934 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
4935 suggestion = Some(format!("self as {}", suggested_name)),
4936 ImportDirectiveSubclass::SingleImport { source, .. } => {
4937 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
4938 .map(|pos| pos as usize) {
4939 if let Ok(snippet) = self.session.source_map()
4940 .span_to_snippet(binding_span) {
4941 if pos <= snippet.len() {
4942 suggestion = Some(format!(
4946 if snippet.ends_with(";") { ";" } else { "" }
4952 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
4953 suggestion = Some(format!(
4954 "extern crate {} as {};",
4955 source.unwrap_or(target.name),
4958 _ => unreachable!(),
4961 let rename_msg = "you can use `as` to change the binding name of the import";
4962 if let Some(suggestion) = suggestion {
4963 err.span_suggestion(
4967 Applicability::MaybeIncorrect,
4970 err.span_label(binding_span, rename_msg);
4974 /// This function adds a suggestion to remove a unnecessary binding from an import that is
4975 /// nested. In the following example, this function will be invoked to remove the `a` binding
4976 /// in the second use statement:
4978 /// ```ignore (diagnostic)
4979 /// use issue_52891::a;
4980 /// use issue_52891::{d, a, e};
4983 /// The following suggestion will be added:
4985 /// ```ignore (diagnostic)
4986 /// use issue_52891::{d, a, e};
4987 /// ^-- help: remove unnecessary import
4990 /// If the nested use contains only one import then the suggestion will remove the entire
4993 /// It is expected that the directive provided is a nested import - this isn't checked by the
4994 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
4995 /// as characters expected by span manipulations won't be present.
4996 fn add_suggestion_for_duplicate_nested_use(
4998 err: &mut DiagnosticBuilder<'_>,
4999 directive: &ImportDirective<'_>,
5002 assert!(directive.is_nested());
5003 let message = "remove unnecessary import";
5004 let source_map = self.session.source_map();
5006 // Two examples will be used to illustrate the span manipulations we're doing:
5008 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5009 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5010 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5011 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5013 // Find the span of everything after the binding.
5014 // ie. `a, e};` or `a};`
5015 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5017 // Find everything after the binding but not including the binding.
5018 // ie. `, e};` or `};`
5019 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5021 // Keep characters in the span until we encounter something that isn't a comma or
5025 // Also note whether a closing brace character was encountered. If there
5026 // was, then later go backwards to remove any trailing commas that are left.
5027 let mut found_closing_brace = false;
5028 let after_binding_until_next_binding = source_map.span_take_while(
5029 after_binding_until_end,
5031 if ch == '}' { found_closing_brace = true; }
5032 ch == ' ' || ch == ','
5036 // Combine the two spans.
5037 // ie. `a, ` or `a`.
5039 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5040 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5042 // If there was a closing brace then identify the span to remove any trailing commas from
5043 // previous imports.
5044 if found_closing_brace {
5045 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5046 // `prev_source` will contain all of the source that came before the span.
5047 // Then split based on a command and take the first (ie. closest to our span)
5048 // snippet. In the example, this is a space.
5049 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5050 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5051 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5052 let prev_comma = prev_comma.first().unwrap();
5053 let prev_starting_brace = prev_starting_brace.first().unwrap();
5055 // If the amount of source code before the comma is greater than
5056 // the amount of source code before the starting brace then we've only
5057 // got one item in the nested item (eg. `issue_52891::{self}`).
5058 if prev_comma.len() > prev_starting_brace.len() {
5059 // So just remove the entire line...
5060 err.span_suggestion(
5061 directive.use_span_with_attributes,
5064 Applicability::MaybeIncorrect,
5069 let span = span.with_lo(BytePos(
5070 // Take away the number of bytes for the characters we've found and an
5071 // extra for the comma.
5072 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5074 err.span_suggestion(
5075 span, message, String::new(), Applicability::MaybeIncorrect,
5082 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5085 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5086 -> Option<&'a NameBinding<'a>> {
5087 if ident.is_path_segment_keyword() {
5088 // Make sure `self`, `super` etc produce an error when passed to here.
5091 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5092 if let Some(binding) = entry.extern_crate_item {
5093 if !speculative && entry.introduced_by_item {
5094 self.record_use(ident, TypeNS, binding, false);
5098 let crate_id = if !speculative {
5099 self.crate_loader.process_path_extern(ident.name, ident.span)
5100 } else if let Some(crate_id) =
5101 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5106 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5107 self.populate_module_if_necessary(&crate_root);
5108 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5109 .to_name_binding(self.arenas))
5115 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5116 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5119 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5120 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5123 fn names_to_string(idents: &[Ident]) -> String {
5124 let mut result = String::new();
5125 for (i, ident) in idents.iter()
5126 .filter(|ident| ident.name != keywords::PathRoot.name())
5129 result.push_str("::");
5131 result.push_str(&ident.as_str());
5136 fn path_names_to_string(path: &Path) -> String {
5137 names_to_string(&path.segments.iter()
5138 .map(|seg| seg.ident)
5139 .collect::<Vec<_>>())
5142 /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5143 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5144 let variant_path = &suggestion.path;
5145 let variant_path_string = path_names_to_string(variant_path);
5147 let path_len = suggestion.path.segments.len();
5148 let enum_path = ast::Path {
5149 span: suggestion.path.span,
5150 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5152 let enum_path_string = path_names_to_string(&enum_path);
5154 (variant_path_string, enum_path_string)
5157 /// When an entity with a given name is not available in scope, we search for
5158 /// entities with that name in all crates. This method allows outputting the
5159 /// results of this search in a programmer-friendly way
5160 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5161 // This is `None` if all placement locations are inside expansions
5163 candidates: &[ImportSuggestion],
5167 // we want consistent results across executions, but candidates are produced
5168 // by iterating through a hash map, so make sure they are ordered:
5169 let mut path_strings: Vec<_> =
5170 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5171 path_strings.sort();
5173 let better = if better { "better " } else { "" };
5174 let msg_diff = match path_strings.len() {
5175 1 => " is found in another module, you can import it",
5176 _ => "s are found in other modules, you can import them",
5178 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5180 if let Some(span) = span {
5181 for candidate in &mut path_strings {
5182 // produce an additional newline to separate the new use statement
5183 // from the directly following item.
5184 let additional_newline = if found_use {
5189 *candidate = format!("use {};\n{}", candidate, additional_newline);
5192 err.span_suggestions(
5195 path_strings.into_iter(),
5196 Applicability::Unspecified,
5201 for candidate in path_strings {
5203 msg.push_str(&candidate);
5208 /// A somewhat inefficient routine to obtain the name of a module.
5209 fn module_to_string(module: Module<'_>) -> Option<String> {
5210 let mut names = Vec::new();
5212 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5213 if let ModuleKind::Def(_, name) = module.kind {
5214 if let Some(parent) = module.parent {
5215 names.push(Ident::with_empty_ctxt(name));
5216 collect_mod(names, parent);
5219 // danger, shouldn't be ident?
5220 names.push(Ident::from_str("<opaque>"));
5221 collect_mod(names, module.parent.unwrap());
5224 collect_mod(&mut names, module);
5226 if names.is_empty() {
5229 Some(names_to_string(&names.into_iter()
5231 .collect::<Vec<_>>()))
5234 fn err_path_resolution() -> PathResolution {
5235 PathResolution::new(Def::Err)
5238 #[derive(Copy, Clone, Debug)]
5240 /// Do not issue the lint.
5243 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
5244 /// In this case, we can take the span of that path.
5247 /// This lint comes from a `use` statement. In this case, what we
5248 /// care about really is the *root* `use` statement; e.g., if we
5249 /// have nested things like `use a::{b, c}`, we care about the
5251 UsePath { root_id: NodeId, root_span: Span },
5253 /// This is the "trait item" from a fully qualified path. For example,
5254 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5255 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5256 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5260 fn node_id(&self) -> Option<NodeId> {
5262 CrateLint::No => None,
5263 CrateLint::SimplePath(id) |
5264 CrateLint::UsePath { root_id: id, .. } |
5265 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5270 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }