1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
16 #![feature(label_break_value)]
18 #![feature(rustc_diagnostic_macros)]
19 #![feature(slice_sort_by_cached_key)]
22 extern crate bitflags;
27 extern crate syntax_pos;
28 extern crate rustc_errors as errors;
32 extern crate rustc_data_structures;
33 extern crate rustc_metadata;
35 pub use rustc::hir::def::{Namespace, PerNS};
37 use self::TypeParameters::*;
40 use rustc::hir::map::{Definitions, DefCollector};
41 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
42 use rustc::middle::cstore::CrateStore;
43 use rustc::session::Session;
45 use rustc::hir::def::*;
46 use rustc::hir::def::Namespace::*;
47 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
48 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
49 use rustc::session::config::nightly_options;
51 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
53 use rustc_metadata::creader::CrateLoader;
54 use rustc_metadata::cstore::CStore;
56 use syntax::source_map::SourceMap;
57 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
58 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
59 use syntax::ext::base::SyntaxExtension;
60 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
61 use syntax::ext::base::MacroKind;
62 use syntax::symbol::{Symbol, keywords};
63 use syntax::util::lev_distance::find_best_match_for_name;
65 use syntax::visit::{self, FnKind, Visitor};
67 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
68 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
69 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
70 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
71 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
74 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
75 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
77 use std::cell::{Cell, RefCell};
78 use std::{cmp, fmt, iter, ptr};
79 use std::collections::BTreeSet;
80 use std::mem::replace;
81 use rustc_data_structures::ptr_key::PtrKey;
82 use rustc_data_structures::sync::Lrc;
84 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
85 use macros::{InvocationData, LegacyBinding, ParentScope};
87 // N.B., this module needs to be declared first so diagnostics are
88 // registered before they are used.
93 mod build_reduced_graph;
96 fn is_known_tool(name: Name) -> bool {
97 ["clippy", "rustfmt"].contains(&&*name.as_str())
107 AbsolutePath(Namespace),
112 /// A free importable items suggested in case of resolution failure.
113 struct ImportSuggestion {
117 /// A field or associated item from self type suggested in case of resolution failure.
118 enum AssocSuggestion {
125 struct BindingError {
127 origin: BTreeSet<Span>,
128 target: BTreeSet<Span>,
131 impl PartialOrd for BindingError {
132 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
133 Some(self.cmp(other))
137 impl PartialEq for BindingError {
138 fn eq(&self, other: &BindingError) -> bool {
139 self.name == other.name
143 impl Ord for BindingError {
144 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
145 self.name.cmp(&other.name)
149 enum ResolutionError<'a> {
150 /// error E0401: can't use type parameters from outer function
151 TypeParametersFromOuterFunction(Def),
152 /// error E0403: the name is already used for a type parameter in this type parameter list
153 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
154 /// error E0407: method is not a member of trait
155 MethodNotMemberOfTrait(Name, &'a str),
156 /// error E0437: type is not a member of trait
157 TypeNotMemberOfTrait(Name, &'a str),
158 /// error E0438: const is not a member of trait
159 ConstNotMemberOfTrait(Name, &'a str),
160 /// error E0408: variable `{}` is not bound in all patterns
161 VariableNotBoundInPattern(&'a BindingError),
162 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
163 VariableBoundWithDifferentMode(Name, Span),
164 /// error E0415: identifier is bound more than once in this parameter list
165 IdentifierBoundMoreThanOnceInParameterList(&'a str),
166 /// error E0416: identifier is bound more than once in the same pattern
167 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
168 /// error E0426: use of undeclared label
169 UndeclaredLabel(&'a str, Option<Name>),
170 /// error E0429: `self` imports are only allowed within a { } list
171 SelfImportsOnlyAllowedWithin,
172 /// error E0430: `self` import can only appear once in the list
173 SelfImportCanOnlyAppearOnceInTheList,
174 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
175 SelfImportOnlyInImportListWithNonEmptyPrefix,
176 /// error E0433: failed to resolve
177 FailedToResolve(&'a str),
178 /// error E0434: can't capture dynamic environment in a fn item
179 CannotCaptureDynamicEnvironmentInFnItem,
180 /// error E0435: attempt to use a non-constant value in a constant
181 AttemptToUseNonConstantValueInConstant,
182 /// error E0530: X bindings cannot shadow Ys
183 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
184 /// error E0128: type parameters with a default cannot use forward declared identifiers
185 ForwardDeclaredTyParam,
188 /// Combines an error with provided span and emits it
190 /// This takes the error provided, combines it with the span and any additional spans inside the
191 /// error and emits it.
192 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
194 resolution_error: ResolutionError<'a>) {
195 resolve_struct_error(resolver, span, resolution_error).emit();
198 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
200 resolution_error: ResolutionError<'a>)
201 -> DiagnosticBuilder<'sess> {
202 match resolution_error {
203 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
204 let mut err = struct_span_err!(resolver.session,
207 "can't use type parameters from outer function");
208 err.span_label(span, "use of type variable from outer function");
210 let cm = resolver.session.source_map();
212 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
213 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
214 resolver.definitions.opt_span(def_id)
217 reduce_impl_span_to_impl_keyword(cm, impl_span),
218 "`Self` type implicitly declared here, by this `impl`",
221 match (maybe_trait_defid, maybe_impl_defid) {
223 err.span_label(span, "can't use `Self` here");
226 err.span_label(span, "use a type here instead");
228 (None, None) => bug!("`impl` without trait nor type?"),
232 Def::TyParam(typaram_defid) => {
233 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
234 err.span_label(typaram_span, "type variable from outer function");
238 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
243 // Try to retrieve the span of the function signature and generate a new message with
244 // a local type parameter
245 let sugg_msg = "try using a local type parameter instead";
246 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
247 // Suggest the modification to the user
248 err.span_suggestion_with_applicability(
252 Applicability::MachineApplicable,
254 } else if let Some(sp) = cm.generate_fn_name_span(span) {
255 err.span_label(sp, "try adding a local type parameter in this method instead");
257 err.help("try using a local type parameter instead");
262 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
263 let mut err = struct_span_err!(resolver.session,
266 "the name `{}` is already used for a type parameter \
267 in this type parameter list",
269 err.span_label(span, "already used");
270 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
273 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
274 let mut err = struct_span_err!(resolver.session,
277 "method `{}` is not a member of trait `{}`",
280 err.span_label(span, format!("not a member of trait `{}`", trait_));
283 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
284 let mut err = struct_span_err!(resolver.session,
287 "type `{}` is not a member of trait `{}`",
290 err.span_label(span, format!("not a member of trait `{}`", trait_));
293 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
294 let mut err = struct_span_err!(resolver.session,
297 "const `{}` is not a member of trait `{}`",
300 err.span_label(span, format!("not a member of trait `{}`", trait_));
303 ResolutionError::VariableNotBoundInPattern(binding_error) => {
304 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
305 let msp = MultiSpan::from_spans(target_sp.clone());
306 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
307 let mut err = resolver.session.struct_span_err_with_code(
310 DiagnosticId::Error("E0408".into()),
312 for sp in target_sp {
313 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
315 let origin_sp = binding_error.origin.iter().cloned();
316 for sp in origin_sp {
317 err.span_label(sp, "variable not in all patterns");
321 ResolutionError::VariableBoundWithDifferentMode(variable_name,
322 first_binding_span) => {
323 let mut err = struct_span_err!(resolver.session,
326 "variable `{}` is bound in inconsistent \
327 ways within the same match arm",
329 err.span_label(span, "bound in different ways");
330 err.span_label(first_binding_span, "first binding");
333 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
334 let mut err = struct_span_err!(resolver.session,
337 "identifier `{}` is bound more than once in this parameter list",
339 err.span_label(span, "used as parameter more than once");
342 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
343 let mut err = struct_span_err!(resolver.session,
346 "identifier `{}` is bound more than once in the same pattern",
348 err.span_label(span, "used in a pattern more than once");
351 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
352 let mut err = struct_span_err!(resolver.session,
355 "use of undeclared label `{}`",
357 if let Some(lev_candidate) = lev_candidate {
358 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
360 err.span_label(span, format!("undeclared label `{}`", name));
364 ResolutionError::SelfImportsOnlyAllowedWithin => {
365 struct_span_err!(resolver.session,
369 "`self` imports are only allowed within a { } list")
371 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
372 let mut err = struct_span_err!(resolver.session, span, E0430,
373 "`self` import can only appear once in an import list");
374 err.span_label(span, "can only appear once in an import list");
377 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
378 let mut err = struct_span_err!(resolver.session, span, E0431,
379 "`self` import can only appear in an import list with \
380 a non-empty prefix");
381 err.span_label(span, "can only appear in an import list with a non-empty prefix");
384 ResolutionError::FailedToResolve(msg) => {
385 let mut err = struct_span_err!(resolver.session, span, E0433,
386 "failed to resolve: {}", msg);
387 err.span_label(span, msg);
390 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
391 let mut err = struct_span_err!(resolver.session,
395 "can't capture dynamic environment in a fn item");
396 err.help("use the `|| { ... }` closure form instead");
399 ResolutionError::AttemptToUseNonConstantValueInConstant => {
400 let mut err = struct_span_err!(resolver.session, span, E0435,
401 "attempt to use a non-constant value in a constant");
402 err.span_label(span, "non-constant value");
405 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
406 let shadows_what = binding.descr();
407 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
408 what_binding, shadows_what);
409 err.span_label(span, format!("cannot be named the same as {} {}",
410 binding.article(), shadows_what));
411 let participle = if binding.is_import() { "imported" } else { "defined" };
412 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
413 err.span_label(binding.span, msg);
416 ResolutionError::ForwardDeclaredTyParam => {
417 let mut err = struct_span_err!(resolver.session, span, E0128,
418 "type parameters with a default cannot use \
419 forward declared identifiers");
421 span, "defaulted type parameters cannot be forward declared".to_string());
427 /// Adjust the impl span so that just the `impl` keyword is taken by removing
428 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
429 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
431 /// Attention: The method used is very fragile since it essentially duplicates the work of the
432 /// parser. If you need to use this function or something similar, please consider updating the
433 /// source_map functions and this function to something more robust.
434 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
435 let impl_span = cm.span_until_char(impl_span, '<');
436 let impl_span = cm.span_until_whitespace(impl_span);
440 #[derive(Copy, Clone, Debug)]
443 binding_mode: BindingMode,
446 /// Map from the name in a pattern to its binding mode.
447 type BindingMap = FxHashMap<Ident, BindingInfo>;
449 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
460 fn descr(self) -> &'static str {
462 PatternSource::Match => "match binding",
463 PatternSource::IfLet => "if let binding",
464 PatternSource::WhileLet => "while let binding",
465 PatternSource::Let => "let binding",
466 PatternSource::For => "for binding",
467 PatternSource::FnParam => "function parameter",
472 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
473 enum AliasPossibility {
478 #[derive(Copy, Clone, Debug)]
479 enum PathSource<'a> {
480 // Type paths `Path`.
482 // Trait paths in bounds or impls.
483 Trait(AliasPossibility),
484 // Expression paths `path`, with optional parent context.
485 Expr(Option<&'a Expr>),
486 // Paths in path patterns `Path`.
488 // Paths in struct expressions and patterns `Path { .. }`.
490 // Paths in tuple struct patterns `Path(..)`.
492 // `m::A::B` in `<T as m::A>::B::C`.
493 TraitItem(Namespace),
494 // Path in `pub(path)`
498 impl<'a> PathSource<'a> {
499 fn namespace(self) -> Namespace {
501 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
502 PathSource::Visibility => TypeNS,
503 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
504 PathSource::TraitItem(ns) => ns,
508 fn global_by_default(self) -> bool {
510 PathSource::Visibility => true,
511 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
512 PathSource::Struct | PathSource::TupleStruct |
513 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
517 fn defer_to_typeck(self) -> bool {
519 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
520 PathSource::Struct | PathSource::TupleStruct => true,
521 PathSource::Trait(_) | PathSource::TraitItem(..) |
522 PathSource::Visibility => false,
526 fn descr_expected(self) -> &'static str {
528 PathSource::Type => "type",
529 PathSource::Trait(_) => "trait",
530 PathSource::Pat => "unit struct/variant or constant",
531 PathSource::Struct => "struct, variant or union type",
532 PathSource::TupleStruct => "tuple struct/variant",
533 PathSource::Visibility => "module",
534 PathSource::TraitItem(ns) => match ns {
535 TypeNS => "associated type",
536 ValueNS => "method or associated constant",
537 MacroNS => bug!("associated macro"),
539 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
540 // "function" here means "anything callable" rather than `Def::Fn`,
541 // this is not precise but usually more helpful than just "value".
542 Some(&ExprKind::Call(..)) => "function",
548 fn is_expected(self, def: Def) -> bool {
550 PathSource::Type => match def {
551 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
552 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
553 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
554 Def::SelfTy(..) | Def::Existential(..) |
555 Def::ForeignTy(..) => true,
558 PathSource::Trait(AliasPossibility::No) => match def {
559 Def::Trait(..) => true,
562 PathSource::Trait(AliasPossibility::Maybe) => match def {
563 Def::Trait(..) => true,
564 Def::TraitAlias(..) => true,
567 PathSource::Expr(..) => match def {
568 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
569 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
570 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
571 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
572 Def::SelfCtor(..) => true,
575 PathSource::Pat => match def {
576 Def::StructCtor(_, CtorKind::Const) |
577 Def::VariantCtor(_, CtorKind::Const) |
578 Def::Const(..) | Def::AssociatedConst(..) |
579 Def::SelfCtor(..) => true,
582 PathSource::TupleStruct => match def {
583 Def::StructCtor(_, CtorKind::Fn) |
584 Def::VariantCtor(_, CtorKind::Fn) |
585 Def::SelfCtor(..) => true,
588 PathSource::Struct => match def {
589 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
590 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
593 PathSource::TraitItem(ns) => match def {
594 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
595 Def::AssociatedTy(..) if ns == TypeNS => true,
598 PathSource::Visibility => match def {
599 Def::Mod(..) => true,
605 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
606 __diagnostic_used!(E0404);
607 __diagnostic_used!(E0405);
608 __diagnostic_used!(E0412);
609 __diagnostic_used!(E0422);
610 __diagnostic_used!(E0423);
611 __diagnostic_used!(E0425);
612 __diagnostic_used!(E0531);
613 __diagnostic_used!(E0532);
614 __diagnostic_used!(E0573);
615 __diagnostic_used!(E0574);
616 __diagnostic_used!(E0575);
617 __diagnostic_used!(E0576);
618 __diagnostic_used!(E0577);
619 __diagnostic_used!(E0578);
620 match (self, has_unexpected_resolution) {
621 (PathSource::Trait(_), true) => "E0404",
622 (PathSource::Trait(_), false) => "E0405",
623 (PathSource::Type, true) => "E0573",
624 (PathSource::Type, false) => "E0412",
625 (PathSource::Struct, true) => "E0574",
626 (PathSource::Struct, false) => "E0422",
627 (PathSource::Expr(..), true) => "E0423",
628 (PathSource::Expr(..), false) => "E0425",
629 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
630 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
631 (PathSource::TraitItem(..), true) => "E0575",
632 (PathSource::TraitItem(..), false) => "E0576",
633 (PathSource::Visibility, true) => "E0577",
634 (PathSource::Visibility, false) => "E0578",
639 // A minimal representation of a path segment. We use this in resolve because
640 // we synthesize 'path segments' which don't have the rest of an AST or HIR
642 #[derive(Clone, Copy, Debug)]
649 fn from_path(path: &Path) -> Vec<Segment> {
650 path.segments.iter().map(|s| s.into()).collect()
653 fn from_ident(ident: Ident) -> Segment {
660 fn names_to_string(segments: &[Segment]) -> String {
661 names_to_string(&segments.iter()
662 .map(|seg| seg.ident)
663 .collect::<Vec<_>>())
667 impl<'a> From<&'a ast::PathSegment> for Segment {
668 fn from(seg: &'a ast::PathSegment) -> Segment {
676 struct UsePlacementFinder {
677 target_module: NodeId,
682 impl UsePlacementFinder {
683 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
684 let mut finder = UsePlacementFinder {
689 visit::walk_crate(&mut finder, krate);
690 (finder.span, finder.found_use)
694 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
697 module: &'tcx ast::Mod,
699 _: &[ast::Attribute],
702 if self.span.is_some() {
705 if node_id != self.target_module {
706 visit::walk_mod(self, module);
709 // find a use statement
710 for item in &module.items {
712 ItemKind::Use(..) => {
713 // don't suggest placing a use before the prelude
714 // import or other generated ones
715 if item.span.ctxt().outer().expn_info().is_none() {
716 self.span = Some(item.span.shrink_to_lo());
717 self.found_use = true;
721 // don't place use before extern crate
722 ItemKind::ExternCrate(_) => {}
723 // but place them before the first other item
724 _ => if self.span.map_or(true, |span| item.span < span ) {
725 if item.span.ctxt().outer().expn_info().is_none() {
726 // don't insert between attributes and an item
727 if item.attrs.is_empty() {
728 self.span = Some(item.span.shrink_to_lo());
730 // find the first attribute on the item
731 for attr in &item.attrs {
732 if self.span.map_or(true, |span| attr.span < span) {
733 self.span = Some(attr.span.shrink_to_lo());
744 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
745 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
746 fn visit_item(&mut self, item: &'tcx Item) {
747 self.resolve_item(item);
749 fn visit_arm(&mut self, arm: &'tcx Arm) {
750 self.resolve_arm(arm);
752 fn visit_block(&mut self, block: &'tcx Block) {
753 self.resolve_block(block);
755 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
756 self.with_constant_rib(|this| {
757 visit::walk_anon_const(this, constant);
760 fn visit_expr(&mut self, expr: &'tcx Expr) {
761 self.resolve_expr(expr, None);
763 fn visit_local(&mut self, local: &'tcx Local) {
764 self.resolve_local(local);
766 fn visit_ty(&mut self, ty: &'tcx Ty) {
768 TyKind::Path(ref qself, ref path) => {
769 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
771 TyKind::ImplicitSelf => {
772 let self_ty = keywords::SelfUpper.ident();
773 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
774 .map_or(Def::Err, |d| d.def());
775 self.record_def(ty.id, PathResolution::new(def));
779 visit::walk_ty(self, ty);
781 fn visit_poly_trait_ref(&mut self,
782 tref: &'tcx ast::PolyTraitRef,
783 m: &'tcx ast::TraitBoundModifier) {
784 self.smart_resolve_path(tref.trait_ref.ref_id, None,
785 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
786 visit::walk_poly_trait_ref(self, tref, m);
788 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
789 let type_parameters = match foreign_item.node {
790 ForeignItemKind::Fn(_, ref generics) => {
791 HasTypeParameters(generics, ItemRibKind)
793 ForeignItemKind::Static(..) => NoTypeParameters,
794 ForeignItemKind::Ty => NoTypeParameters,
795 ForeignItemKind::Macro(..) => NoTypeParameters,
797 self.with_type_parameter_rib(type_parameters, |this| {
798 visit::walk_foreign_item(this, foreign_item);
801 fn visit_fn(&mut self,
802 function_kind: FnKind<'tcx>,
803 declaration: &'tcx FnDecl,
807 let (rib_kind, asyncness) = match function_kind {
808 FnKind::ItemFn(_, ref header, ..) =>
809 (ItemRibKind, header.asyncness),
810 FnKind::Method(_, ref sig, _, _) =>
811 (TraitOrImplItemRibKind, sig.header.asyncness),
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();
863 fn visit_generics(&mut self, generics: &'tcx Generics) {
864 // For type parameter defaults, we have to ban access
865 // to following type parameters, as the Substs can only
866 // provide previous type parameters as they're built. We
867 // put all the parameters on the ban list and then remove
868 // them one by one as they are processed and become available.
869 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
870 let mut found_default = false;
871 default_ban_rib.bindings.extend(generics.params.iter()
872 .filter_map(|param| match param.kind {
873 GenericParamKind::Lifetime { .. } => None,
874 GenericParamKind::Type { ref default, .. } => {
875 found_default |= default.is_some();
877 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
884 for param in &generics.params {
886 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
887 GenericParamKind::Type { ref default, .. } => {
888 for bound in ¶m.bounds {
889 self.visit_param_bound(bound);
892 if let Some(ref ty) = default {
893 self.ribs[TypeNS].push(default_ban_rib);
895 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
898 // Allow all following defaults to refer to this type parameter.
899 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
903 for p in &generics.where_clause.predicates {
904 self.visit_where_predicate(p);
909 #[derive(Copy, Clone)]
910 enum TypeParameters<'a, 'b> {
912 HasTypeParameters(// Type parameters.
915 // The kind of the rib used for type parameters.
919 /// The rib kind controls the translation of local
920 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
921 #[derive(Copy, Clone, Debug)]
923 /// No translation needs to be applied.
926 /// We passed through a closure scope at the given node ID.
927 /// Translate upvars as appropriate.
928 ClosureRibKind(NodeId /* func id */),
930 /// We passed through an impl or trait and are now in one of its
931 /// methods or associated types. Allow references to ty params that impl or trait
932 /// binds. Disallow any other upvars (including other ty params that are
934 TraitOrImplItemRibKind,
936 /// We passed through an item scope. Disallow upvars.
939 /// We're in a constant item. Can't refer to dynamic stuff.
942 /// We passed through a module.
943 ModuleRibKind(Module<'a>),
945 /// We passed through a `macro_rules!` statement
946 MacroDefinition(DefId),
948 /// All bindings in this rib are type parameters that can't be used
949 /// from the default of a type parameter because they're not declared
950 /// before said type parameter. Also see the `visit_generics` override.
951 ForwardTyParamBanRibKind,
956 /// A rib represents a scope names can live in. Note that these appear in many places, not just
957 /// around braces. At any place where the list of accessible names (of the given namespace)
958 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
959 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
962 /// Different [rib kinds](enum.RibKind) are transparent for different names.
964 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
965 /// resolving, the name is looked up from inside out.
968 bindings: FxHashMap<Ident, Def>,
973 fn new(kind: RibKind<'a>) -> Rib<'a> {
975 bindings: Default::default(),
981 /// An intermediate resolution result.
983 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
984 /// items are visible in their whole block, while defs only from the place they are defined
986 enum LexicalScopeBinding<'a> {
987 Item(&'a NameBinding<'a>),
991 impl<'a> LexicalScopeBinding<'a> {
992 fn item(self) -> Option<&'a NameBinding<'a>> {
994 LexicalScopeBinding::Item(binding) => Some(binding),
999 fn def(self) -> Def {
1001 LexicalScopeBinding::Item(binding) => binding.def(),
1002 LexicalScopeBinding::Def(def) => def,
1007 #[derive(Copy, Clone, Debug)]
1008 enum ModuleOrUniformRoot<'a> {
1012 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1013 CrateRootAndExternPrelude,
1015 /// Virtual module that denotes resolution in extern prelude.
1016 /// Used for paths starting with `::` on 2018 edition or `extern::`.
1019 /// Virtual module that denotes resolution in current scope.
1020 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1021 /// are always split into two parts, the first of which should be some kind of module.
1025 impl<'a> PartialEq for ModuleOrUniformRoot<'a> {
1026 fn eq(&self, other: &Self) -> bool {
1027 match (*self, *other) {
1028 (ModuleOrUniformRoot::Module(lhs),
1029 ModuleOrUniformRoot::Module(rhs)) => ptr::eq(lhs, rhs),
1030 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1031 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1032 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1033 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1039 #[derive(Clone, Debug)]
1040 enum PathResult<'a> {
1041 Module(ModuleOrUniformRoot<'a>),
1042 NonModule(PathResolution),
1044 Failed(Span, String, bool /* is the error from the last segment? */),
1048 /// An anonymous module, eg. just a block.
1052 /// fn f() {} // (1)
1053 /// { // This is an anonymous module
1054 /// f(); // This resolves to (2) as we are inside the block.
1055 /// fn f() {} // (2)
1057 /// f(); // Resolves to (1)
1061 /// Any module with a name.
1065 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1066 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1071 /// One node in the tree of modules.
1072 pub struct ModuleData<'a> {
1073 parent: Option<Module<'a>>,
1076 // The def id of the closest normal module (`mod`) ancestor (including this module).
1077 normal_ancestor_id: DefId,
1079 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1080 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1081 Option<&'a NameBinding<'a>>)>>,
1082 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1084 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1086 // Macro invocations that can expand into items in this module.
1087 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1089 no_implicit_prelude: bool,
1091 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1092 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1094 // Used to memoize the traits in this module for faster searches through all traits in scope.
1095 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1097 // Whether this module is populated. If not populated, any attempt to
1098 // access the children must be preceded with a
1099 // `populate_module_if_necessary` call.
1100 populated: Cell<bool>,
1102 /// Span of the module itself. Used for error reporting.
1108 type Module<'a> = &'a ModuleData<'a>;
1110 impl<'a> ModuleData<'a> {
1111 fn new(parent: Option<Module<'a>>,
1113 normal_ancestor_id: DefId,
1115 span: Span) -> Self {
1120 resolutions: Default::default(),
1121 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1122 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1123 builtin_attrs: RefCell::new(Vec::new()),
1124 unresolved_invocations: Default::default(),
1125 no_implicit_prelude: false,
1126 glob_importers: RefCell::new(Vec::new()),
1127 globs: RefCell::new(Vec::new()),
1128 traits: RefCell::new(None),
1129 populated: Cell::new(normal_ancestor_id.is_local()),
1135 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1136 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1137 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1141 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1142 let resolutions = self.resolutions.borrow();
1143 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1144 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1145 for &(&(ident, ns), &resolution) in resolutions.iter() {
1146 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1150 fn def(&self) -> Option<Def> {
1152 ModuleKind::Def(def, _) => Some(def),
1157 fn def_id(&self) -> Option<DefId> {
1158 self.def().as_ref().map(Def::def_id)
1161 // `self` resolves to the first module ancestor that `is_normal`.
1162 fn is_normal(&self) -> bool {
1164 ModuleKind::Def(Def::Mod(_), _) => true,
1169 fn is_trait(&self) -> bool {
1171 ModuleKind::Def(Def::Trait(_), _) => true,
1176 fn nearest_item_scope(&'a self) -> Module<'a> {
1177 if self.is_trait() { self.parent.unwrap() } else { self }
1180 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1181 while !ptr::eq(self, other) {
1182 if let Some(parent) = other.parent {
1192 impl<'a> fmt::Debug for ModuleData<'a> {
1193 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1194 write!(f, "{:?}", self.def())
1198 /// Records a possibly-private value, type, or module definition.
1199 #[derive(Clone, Debug)]
1200 pub struct NameBinding<'a> {
1201 kind: NameBindingKind<'a>,
1204 vis: ty::Visibility,
1207 pub trait ToNameBinding<'a> {
1208 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1211 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1212 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1217 #[derive(Clone, Debug)]
1218 enum NameBindingKind<'a> {
1219 Def(Def, /* is_macro_export */ bool),
1222 binding: &'a NameBinding<'a>,
1223 directive: &'a ImportDirective<'a>,
1227 kind: AmbiguityKind,
1228 b1: &'a NameBinding<'a>,
1229 b2: &'a NameBinding<'a>,
1233 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1235 struct UseError<'a> {
1236 err: DiagnosticBuilder<'a>,
1237 /// Attach `use` statements for these candidates
1238 candidates: Vec<ImportSuggestion>,
1239 /// The node id of the module to place the use statements in
1241 /// Whether the diagnostic should state that it's "better"
1245 #[derive(Clone, Copy, PartialEq, Debug)]
1246 enum AmbiguityKind {
1251 LegacyHelperVsPrelude,
1256 MoreExpandedVsOuter,
1259 impl AmbiguityKind {
1260 fn descr(self) -> &'static str {
1262 AmbiguityKind::Import =>
1263 "name vs any other name during import resolution",
1264 AmbiguityKind::AbsolutePath =>
1265 "name in the crate root vs extern crate during absolute path resolution",
1266 AmbiguityKind::BuiltinAttr =>
1267 "built-in attribute vs any other name",
1268 AmbiguityKind::DeriveHelper =>
1269 "derive helper attribute vs any other name",
1270 AmbiguityKind::LegacyHelperVsPrelude =>
1271 "legacy plugin helper attribute vs name from prelude",
1272 AmbiguityKind::LegacyVsModern =>
1273 "`macro_rules` vs non-`macro_rules` from other module",
1274 AmbiguityKind::GlobVsOuter =>
1275 "glob import vs any other name from outer scope during import/macro resolution",
1276 AmbiguityKind::GlobVsGlob =>
1277 "glob import vs glob import in the same module",
1278 AmbiguityKind::GlobVsExpanded =>
1279 "glob import vs macro-expanded name in the same \
1280 module during import/macro resolution",
1281 AmbiguityKind::MoreExpandedVsOuter =>
1282 "macro-expanded name vs less macro-expanded name \
1283 from outer scope during import/macro resolution",
1288 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1289 #[derive(Clone, Copy, PartialEq)]
1290 enum AmbiguityErrorMisc {
1297 struct AmbiguityError<'a> {
1298 kind: AmbiguityKind,
1300 b1: &'a NameBinding<'a>,
1301 b2: &'a NameBinding<'a>,
1302 misc1: AmbiguityErrorMisc,
1303 misc2: AmbiguityErrorMisc,
1306 impl<'a> NameBinding<'a> {
1307 fn module(&self) -> Option<Module<'a>> {
1309 NameBindingKind::Module(module) => Some(module),
1310 NameBindingKind::Import { binding, .. } => binding.module(),
1315 fn def(&self) -> Def {
1317 NameBindingKind::Def(def, _) => def,
1318 NameBindingKind::Module(module) => module.def().unwrap(),
1319 NameBindingKind::Import { binding, .. } => binding.def(),
1320 NameBindingKind::Ambiguity { .. } => Def::Err,
1324 fn def_ignoring_ambiguity(&self) -> Def {
1326 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1327 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1332 // We sometimes need to treat variants as `pub` for backwards compatibility
1333 fn pseudo_vis(&self) -> ty::Visibility {
1334 if self.is_variant() && self.def().def_id().is_local() {
1335 ty::Visibility::Public
1341 fn is_variant(&self) -> bool {
1343 NameBindingKind::Def(Def::Variant(..), _) |
1344 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1349 fn is_extern_crate(&self) -> bool {
1351 NameBindingKind::Import {
1352 directive: &ImportDirective {
1353 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1356 NameBindingKind::Module(
1357 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1358 ) => def_id.index == CRATE_DEF_INDEX,
1363 fn is_import(&self) -> bool {
1365 NameBindingKind::Import { .. } => true,
1370 fn is_glob_import(&self) -> bool {
1372 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1373 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1378 fn is_importable(&self) -> bool {
1380 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1385 fn is_macro_def(&self) -> bool {
1387 NameBindingKind::Def(Def::Macro(..), _) => true,
1392 fn macro_kind(&self) -> Option<MacroKind> {
1393 match self.def_ignoring_ambiguity() {
1394 Def::Macro(_, kind) => Some(kind),
1395 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1400 fn descr(&self) -> &'static str {
1401 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1404 fn article(&self) -> &'static str {
1405 if self.is_extern_crate() { "an" } else { self.def().article() }
1408 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1409 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1410 // Then this function returns `true` if `self` may emerge from a macro *after* that
1411 // in some later round and screw up our previously found resolution.
1412 // See more detailed explanation in
1413 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1414 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1415 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1416 // Expansions are partially ordered, so "may appear after" is an inversion of
1417 // "certainly appears before or simultaneously" and includes unordered cases.
1418 let self_parent_expansion = self.expansion;
1419 let other_parent_expansion = binding.expansion;
1420 let certainly_before_other_or_simultaneously =
1421 other_parent_expansion.is_descendant_of(self_parent_expansion);
1422 let certainly_before_invoc_or_simultaneously =
1423 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1424 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1428 /// Interns the names of the primitive types.
1430 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1431 /// special handling, since they have no place of origin.
1433 struct PrimitiveTypeTable {
1434 primitive_types: FxHashMap<Name, PrimTy>,
1437 impl PrimitiveTypeTable {
1438 fn new() -> PrimitiveTypeTable {
1439 let mut table = PrimitiveTypeTable::default();
1441 table.intern("bool", Bool);
1442 table.intern("char", Char);
1443 table.intern("f32", Float(FloatTy::F32));
1444 table.intern("f64", Float(FloatTy::F64));
1445 table.intern("isize", Int(IntTy::Isize));
1446 table.intern("i8", Int(IntTy::I8));
1447 table.intern("i16", Int(IntTy::I16));
1448 table.intern("i32", Int(IntTy::I32));
1449 table.intern("i64", Int(IntTy::I64));
1450 table.intern("i128", Int(IntTy::I128));
1451 table.intern("str", Str);
1452 table.intern("usize", Uint(UintTy::Usize));
1453 table.intern("u8", Uint(UintTy::U8));
1454 table.intern("u16", Uint(UintTy::U16));
1455 table.intern("u32", Uint(UintTy::U32));
1456 table.intern("u64", Uint(UintTy::U64));
1457 table.intern("u128", Uint(UintTy::U128));
1461 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1462 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1466 #[derive(Default, Clone)]
1467 pub struct ExternPreludeEntry<'a> {
1468 extern_crate_item: Option<&'a NameBinding<'a>>,
1469 pub introduced_by_item: bool,
1472 /// The main resolver class.
1474 /// This is the visitor that walks the whole crate.
1475 pub struct Resolver<'a> {
1476 session: &'a Session,
1479 pub definitions: Definitions,
1481 graph_root: Module<'a>,
1483 prelude: Option<Module<'a>>,
1484 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1486 /// n.b. This is used only for better diagnostics, not name resolution itself.
1487 has_self: FxHashSet<DefId>,
1489 /// Names of fields of an item `DefId` accessible with dot syntax.
1490 /// Used for hints during error reporting.
1491 field_names: FxHashMap<DefId, Vec<Name>>,
1493 /// All imports known to succeed or fail.
1494 determined_imports: Vec<&'a ImportDirective<'a>>,
1496 /// All non-determined imports.
1497 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1499 /// The module that represents the current item scope.
1500 current_module: Module<'a>,
1502 /// The current set of local scopes for types and values.
1503 /// FIXME #4948: Reuse ribs to avoid allocation.
1504 ribs: PerNS<Vec<Rib<'a>>>,
1506 /// The current set of local scopes, for labels.
1507 label_ribs: Vec<Rib<'a>>,
1509 /// The trait that the current context can refer to.
1510 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1512 /// The current self type if inside an impl (used for better errors).
1513 current_self_type: Option<Ty>,
1515 /// The current self item if inside an ADT (used for better errors).
1516 current_self_item: Option<NodeId>,
1518 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1519 /// We are resolving a last import segment during import validation.
1520 last_import_segment: bool,
1521 /// This binding should be ignored during in-module resolution, so that we don't get
1522 /// "self-confirming" import resolutions during import validation.
1523 blacklisted_binding: Option<&'a NameBinding<'a>>,
1525 /// The idents for the primitive types.
1526 primitive_type_table: PrimitiveTypeTable,
1529 import_map: ImportMap,
1530 pub freevars: FreevarMap,
1531 freevars_seen: NodeMap<NodeMap<usize>>,
1532 pub export_map: ExportMap,
1533 pub trait_map: TraitMap,
1535 /// A map from nodes to anonymous modules.
1536 /// Anonymous modules are pseudo-modules that are implicitly created around items
1537 /// contained within blocks.
1539 /// For example, if we have this:
1547 /// There will be an anonymous module created around `g` with the ID of the
1548 /// entry block for `f`.
1549 block_map: NodeMap<Module<'a>>,
1550 module_map: FxHashMap<DefId, Module<'a>>,
1551 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1552 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1554 pub make_glob_map: bool,
1555 /// Maps imports to the names of items actually imported (this actually maps
1556 /// all imports, but only glob imports are actually interesting).
1557 pub glob_map: GlobMap,
1559 used_imports: FxHashSet<(NodeId, Namespace)>,
1560 pub maybe_unused_trait_imports: NodeSet,
1561 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1563 /// A list of labels as of yet unused. Labels will be removed from this map when
1564 /// they are used (in a `break` or `continue` statement)
1565 pub unused_labels: FxHashMap<NodeId, Span>,
1567 /// privacy errors are delayed until the end in order to deduplicate them
1568 privacy_errors: Vec<PrivacyError<'a>>,
1569 /// ambiguity errors are delayed for deduplication
1570 ambiguity_errors: Vec<AmbiguityError<'a>>,
1571 /// `use` injections are delayed for better placement and deduplication
1572 use_injections: Vec<UseError<'a>>,
1573 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1574 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1576 arenas: &'a ResolverArenas<'a>,
1577 dummy_binding: &'a NameBinding<'a>,
1579 crate_loader: &'a mut CrateLoader<'a>,
1580 macro_names: FxHashSet<Ident>,
1581 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1582 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1583 pub all_macros: FxHashMap<Name, Def>,
1584 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1585 macro_defs: FxHashMap<Mark, DefId>,
1586 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1587 pub found_unresolved_macro: bool,
1589 /// List of crate local macros that we need to warn about as being unused.
1590 /// Right now this only includes macro_rules! macros, and macros 2.0.
1591 unused_macros: FxHashSet<DefId>,
1593 /// Maps the `Mark` of an expansion to its containing module or block.
1594 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1596 /// Avoid duplicated errors for "name already defined".
1597 name_already_seen: FxHashMap<Name, Span>,
1599 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1601 /// This table maps struct IDs into struct constructor IDs,
1602 /// it's not used during normal resolution, only for better error reporting.
1603 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1605 /// Only used for better errors on `fn(): fn()`
1606 current_type_ascription: Vec<Span>,
1608 injected_crate: Option<Module<'a>>,
1611 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1613 pub struct ResolverArenas<'a> {
1614 modules: arena::TypedArena<ModuleData<'a>>,
1615 local_modules: RefCell<Vec<Module<'a>>>,
1616 name_bindings: arena::TypedArena<NameBinding<'a>>,
1617 import_directives: arena::TypedArena<ImportDirective<'a>>,
1618 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1619 invocation_data: arena::TypedArena<InvocationData<'a>>,
1620 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1623 impl<'a> ResolverArenas<'a> {
1624 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1625 let module = self.modules.alloc(module);
1626 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1627 self.local_modules.borrow_mut().push(module);
1631 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1632 self.local_modules.borrow()
1634 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1635 self.name_bindings.alloc(name_binding)
1637 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1638 -> &'a ImportDirective {
1639 self.import_directives.alloc(import_directive)
1641 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1642 self.name_resolutions.alloc(Default::default())
1644 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1645 -> &'a InvocationData<'a> {
1646 self.invocation_data.alloc(expansion_data)
1648 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1649 self.legacy_bindings.alloc(binding)
1653 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1654 fn parent(self, id: DefId) -> Option<DefId> {
1656 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1657 _ => self.cstore.def_key(id).parent,
1658 }.map(|index| DefId { index, ..id })
1662 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1663 /// the resolver is no longer needed as all the relevant information is inline.
1664 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1665 fn resolve_hir_path(
1670 self.resolve_hir_path_cb(path, is_value,
1671 |resolver, span, error| resolve_error(resolver, span, error))
1674 fn resolve_str_path(
1677 crate_root: Option<&str>,
1678 components: &[&str],
1681 let segments = iter::once(keywords::PathRoot.ident())
1683 crate_root.into_iter()
1684 .chain(components.iter().cloned())
1685 .map(Ident::from_str)
1686 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1689 let path = ast::Path {
1694 self.resolve_hir_path(&path, is_value)
1697 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1698 self.def_map.get(&id).cloned()
1701 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1702 self.import_map.get(&id).cloned().unwrap_or_default()
1705 fn definitions(&mut self) -> &mut Definitions {
1706 &mut self.definitions
1710 impl<'a> Resolver<'a> {
1711 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1712 /// isn't something that can be returned because it can't be made to live that long,
1713 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1714 /// just that an error occurred.
1715 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1716 -> Result<hir::Path, ()> {
1718 let mut errored = false;
1720 let path = if path_str.starts_with("::") {
1723 segments: iter::once(keywords::PathRoot.ident())
1725 path_str.split("::").skip(1).map(Ident::from_str)
1727 .map(|i| self.new_ast_path_segment(i))
1735 .map(Ident::from_str)
1736 .map(|i| self.new_ast_path_segment(i))
1740 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1741 if errored || path.def == Def::Err {
1748 /// resolve_hir_path, but takes a callback in case there was an error
1749 fn resolve_hir_path_cb<F>(
1755 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1757 let namespace = if is_value { ValueNS } else { TypeNS };
1758 let span = path.span;
1759 let segments = &path.segments;
1760 let path = Segment::from_path(&path);
1761 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1762 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1763 span, CrateLint::No) {
1764 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1765 module.def().unwrap(),
1766 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1767 path_res.base_def(),
1768 PathResult::NonModule(..) => {
1769 let msg = "type-relative paths are not supported in this context";
1770 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1773 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1774 PathResult::Failed(span, msg, _) => {
1775 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1780 let segments: Vec<_> = segments.iter().map(|seg| {
1781 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1782 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1788 segments: segments.into(),
1792 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1793 let mut seg = ast::PathSegment::from_ident(ident);
1794 seg.id = self.session.next_node_id();
1799 impl<'a> Resolver<'a> {
1800 pub fn new(session: &'a Session,
1804 make_glob_map: MakeGlobMap,
1805 crate_loader: &'a mut CrateLoader<'a>,
1806 arenas: &'a ResolverArenas<'a>)
1808 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1809 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1810 let graph_root = arenas.alloc_module(ModuleData {
1811 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1812 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1814 let mut module_map = FxHashMap::default();
1815 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1817 let mut definitions = Definitions::new();
1818 DefCollector::new(&mut definitions, Mark::root())
1819 .collect_root(crate_name, session.local_crate_disambiguator());
1821 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1822 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1825 if !attr::contains_name(&krate.attrs, "no_core") {
1826 extern_prelude.insert(Ident::from_str("core"), Default::default());
1827 if !attr::contains_name(&krate.attrs, "no_std") {
1828 extern_prelude.insert(Ident::from_str("std"), Default::default());
1829 if session.rust_2018() {
1830 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1835 let mut invocations = FxHashMap::default();
1836 invocations.insert(Mark::root(),
1837 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1839 let mut macro_defs = FxHashMap::default();
1840 macro_defs.insert(Mark::root(), root_def_id);
1849 // The outermost module has def ID 0; this is not reflected in the
1855 has_self: FxHashSet::default(),
1856 field_names: FxHashMap::default(),
1858 determined_imports: Vec::new(),
1859 indeterminate_imports: Vec::new(),
1861 current_module: graph_root,
1863 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1864 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1865 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1867 label_ribs: Vec::new(),
1869 current_trait_ref: None,
1870 current_self_type: None,
1871 current_self_item: None,
1872 last_import_segment: false,
1873 blacklisted_binding: None,
1875 primitive_type_table: PrimitiveTypeTable::new(),
1877 def_map: Default::default(),
1878 import_map: Default::default(),
1879 freevars: Default::default(),
1880 freevars_seen: Default::default(),
1881 export_map: FxHashMap::default(),
1882 trait_map: Default::default(),
1884 block_map: Default::default(),
1885 extern_module_map: FxHashMap::default(),
1886 binding_parent_modules: FxHashMap::default(),
1888 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1889 glob_map: Default::default(),
1891 used_imports: FxHashSet::default(),
1892 maybe_unused_trait_imports: Default::default(),
1893 maybe_unused_extern_crates: Vec::new(),
1895 unused_labels: FxHashMap::default(),
1897 privacy_errors: Vec::new(),
1898 ambiguity_errors: Vec::new(),
1899 use_injections: Vec::new(),
1900 macro_expanded_macro_export_errors: BTreeSet::new(),
1903 dummy_binding: arenas.alloc_name_binding(NameBinding {
1904 kind: NameBindingKind::Def(Def::Err, false),
1905 expansion: Mark::root(),
1907 vis: ty::Visibility::Public,
1911 macro_names: FxHashSet::default(),
1912 builtin_macros: FxHashMap::default(),
1913 macro_use_prelude: FxHashMap::default(),
1914 all_macros: FxHashMap::default(),
1915 macro_map: FxHashMap::default(),
1918 local_macro_def_scopes: FxHashMap::default(),
1919 name_already_seen: FxHashMap::default(),
1920 potentially_unused_imports: Vec::new(),
1921 struct_constructors: Default::default(),
1922 found_unresolved_macro: false,
1923 unused_macros: FxHashSet::default(),
1924 current_type_ascription: Vec::new(),
1925 injected_crate: None,
1929 pub fn arenas() -> ResolverArenas<'a> {
1933 /// Runs the function on each namespace.
1934 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1940 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1942 match self.macro_defs.get(&ctxt.outer()) {
1943 Some(&def_id) => return def_id,
1944 None => ctxt.remove_mark(),
1949 /// Entry point to crate resolution.
1950 pub fn resolve_crate(&mut self, krate: &Crate) {
1951 ImportResolver { resolver: self }.finalize_imports();
1952 self.current_module = self.graph_root;
1953 self.finalize_current_module_macro_resolutions();
1955 visit::walk_crate(self, krate);
1957 check_unused::check_crate(self, krate);
1958 self.report_errors(krate);
1959 self.crate_loader.postprocess(krate);
1966 normal_ancestor_id: DefId,
1970 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1971 self.arenas.alloc_module(module)
1974 fn record_use(&mut self, ident: Ident, ns: Namespace,
1975 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1976 match used_binding.kind {
1977 NameBindingKind::Import { directive, binding, ref used } if !used.get() => {
1978 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1979 // but not introduce it, as used if they are accessed from lexical scope.
1980 if is_lexical_scope {
1981 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1982 if let Some(crate_item) = entry.extern_crate_item {
1983 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1990 directive.used.set(true);
1991 self.used_imports.insert((directive.id, ns));
1992 self.add_to_glob_map(directive.id, ident);
1993 self.record_use(ident, ns, binding, false);
1995 NameBindingKind::Ambiguity { kind, b1, b2 } => {
1996 self.ambiguity_errors.push(AmbiguityError {
1997 kind, ident, b1, b2,
1998 misc1: AmbiguityErrorMisc::None,
1999 misc2: AmbiguityErrorMisc::None,
2006 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
2007 if self.make_glob_map {
2008 self.glob_map.entry(id).or_default().insert(ident.name);
2012 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2013 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2014 /// `ident` in the first scope that defines it (or None if no scopes define it).
2016 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2017 /// the items are defined in the block. For example,
2020 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2023 /// g(); // This resolves to the local variable `g` since it shadows the item.
2027 /// Invariant: This must only be called during main resolution, not during
2028 /// import resolution.
2029 fn resolve_ident_in_lexical_scope(&mut self,
2032 record_used_id: Option<NodeId>,
2034 -> Option<LexicalScopeBinding<'a>> {
2035 let record_used = record_used_id.is_some();
2036 assert!(ns == TypeNS || ns == ValueNS);
2038 ident.span = if ident.name == keywords::SelfUpper.name() {
2039 // FIXME(jseyfried) improve `Self` hygiene
2040 ident.span.with_ctxt(SyntaxContext::empty())
2045 ident = ident.modern_and_legacy();
2048 // Walk backwards up the ribs in scope.
2049 let mut module = self.graph_root;
2050 for i in (0 .. self.ribs[ns].len()).rev() {
2051 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2052 // The ident resolves to a type parameter or local variable.
2053 return Some(LexicalScopeBinding::Def(
2054 self.adjust_local_def(ns, i, def, record_used, path_span)
2058 module = match self.ribs[ns][i].kind {
2059 ModuleRibKind(module) => module,
2060 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2061 // If an invocation of this macro created `ident`, give up on `ident`
2062 // and switch to `ident`'s source from the macro definition.
2063 ident.span.remove_mark();
2069 let item = self.resolve_ident_in_module_unadjusted(
2070 ModuleOrUniformRoot::Module(module),
2076 if let Ok(binding) = item {
2077 // The ident resolves to an item.
2078 return Some(LexicalScopeBinding::Item(binding));
2082 ModuleKind::Block(..) => {}, // We can see through blocks
2087 ident.span = ident.span.modern();
2088 let mut poisoned = None;
2090 let opt_module = if let Some(node_id) = record_used_id {
2091 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2092 node_id, &mut poisoned)
2094 self.hygienic_lexical_parent(module, &mut ident.span)
2096 module = unwrap_or!(opt_module, break);
2097 let orig_current_module = self.current_module;
2098 self.current_module = module; // Lexical resolutions can never be a privacy error.
2099 let result = self.resolve_ident_in_module_unadjusted(
2100 ModuleOrUniformRoot::Module(module),
2106 self.current_module = orig_current_module;
2110 if let Some(node_id) = poisoned {
2111 self.session.buffer_lint_with_diagnostic(
2112 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2113 node_id, ident.span,
2114 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2115 lint::builtin::BuiltinLintDiagnostics::
2116 ProcMacroDeriveResolutionFallback(ident.span),
2119 return Some(LexicalScopeBinding::Item(binding))
2121 Err(Determined) => continue,
2122 Err(Undetermined) =>
2123 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2127 if !module.no_implicit_prelude {
2129 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2130 return Some(LexicalScopeBinding::Item(binding));
2133 if ns == TypeNS && is_known_tool(ident.name) {
2134 let binding = (Def::ToolMod, ty::Visibility::Public,
2135 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2136 return Some(LexicalScopeBinding::Item(binding));
2138 if let Some(prelude) = self.prelude {
2139 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2140 ModuleOrUniformRoot::Module(prelude),
2146 return Some(LexicalScopeBinding::Item(binding));
2154 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2155 -> Option<Module<'a>> {
2156 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2157 return Some(self.macro_def_scope(span.remove_mark()));
2160 if let ModuleKind::Block(..) = module.kind {
2161 return Some(module.parent.unwrap());
2167 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2168 span: &mut Span, node_id: NodeId,
2169 poisoned: &mut Option<NodeId>)
2170 -> Option<Module<'a>> {
2171 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2175 // We need to support the next case under a deprecation warning
2178 // ---- begin: this comes from a proc macro derive
2179 // mod implementation_details {
2180 // // Note that `MyStruct` is not in scope here.
2181 // impl SomeTrait for MyStruct { ... }
2185 // So we have to fall back to the module's parent during lexical resolution in this case.
2186 if let Some(parent) = module.parent {
2187 // Inner module is inside the macro, parent module is outside of the macro.
2188 if module.expansion != parent.expansion &&
2189 module.expansion.is_descendant_of(parent.expansion) {
2190 // The macro is a proc macro derive
2191 if module.expansion.looks_like_proc_macro_derive() {
2192 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2193 *poisoned = Some(node_id);
2194 return module.parent;
2203 fn resolve_ident_in_module(
2205 module: ModuleOrUniformRoot<'a>,
2208 parent_scope: Option<&ParentScope<'a>>,
2211 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2212 self.resolve_ident_in_module_ext(
2213 module, ident, ns, parent_scope, record_used, path_span
2214 ).map_err(|(determinacy, _)| determinacy)
2217 fn resolve_ident_in_module_ext(
2219 module: ModuleOrUniformRoot<'a>,
2222 parent_scope: Option<&ParentScope<'a>>,
2225 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2226 let orig_current_module = self.current_module;
2228 ModuleOrUniformRoot::Module(module) => {
2229 ident.span = ident.span.modern();
2230 if let Some(def) = ident.span.adjust(module.expansion) {
2231 self.current_module = self.macro_def_scope(def);
2234 ModuleOrUniformRoot::ExternPrelude => {
2235 ident.span = ident.span.modern();
2236 ident.span.adjust(Mark::root());
2238 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2239 ModuleOrUniformRoot::CurrentScope => {
2243 let result = self.resolve_ident_in_module_unadjusted_ext(
2244 module, ident, ns, parent_scope, false, record_used, path_span,
2246 self.current_module = orig_current_module;
2250 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2251 let mut ctxt = ident.span.ctxt();
2252 let mark = if ident.name == keywords::DollarCrate.name() {
2253 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2254 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2255 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2256 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2257 // definitions actually produced by `macro` and `macro` definitions produced by
2258 // `macro_rules!`, but at least such configurations are not stable yet.
2259 ctxt = ctxt.modern_and_legacy();
2260 let mut iter = ctxt.marks().into_iter().rev().peekable();
2261 let mut result = None;
2262 // Find the last modern mark from the end if it exists.
2263 while let Some(&(mark, transparency)) = iter.peek() {
2264 if transparency == Transparency::Opaque {
2265 result = Some(mark);
2271 // Then find the last legacy mark from the end if it exists.
2272 for (mark, transparency) in iter {
2273 if transparency == Transparency::SemiTransparent {
2274 result = Some(mark);
2281 ctxt = ctxt.modern();
2282 ctxt.adjust(Mark::root())
2284 let module = match mark {
2285 Some(def) => self.macro_def_scope(def),
2286 None => return self.graph_root,
2288 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2291 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2292 let mut module = self.get_module(module.normal_ancestor_id);
2293 while module.span.ctxt().modern() != *ctxt {
2294 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2295 module = self.get_module(parent.normal_ancestor_id);
2302 // We maintain a list of value ribs and type ribs.
2304 // Simultaneously, we keep track of the current position in the module
2305 // graph in the `current_module` pointer. When we go to resolve a name in
2306 // the value or type namespaces, we first look through all the ribs and
2307 // then query the module graph. When we resolve a name in the module
2308 // namespace, we can skip all the ribs (since nested modules are not
2309 // allowed within blocks in Rust) and jump straight to the current module
2312 // Named implementations are handled separately. When we find a method
2313 // call, we consult the module node to find all of the implementations in
2314 // scope. This information is lazily cached in the module node. We then
2315 // generate a fake "implementation scope" containing all the
2316 // implementations thus found, for compatibility with old resolve pass.
2318 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2319 where F: FnOnce(&mut Resolver) -> T
2321 let id = self.definitions.local_def_id(id);
2322 let module = self.module_map.get(&id).cloned(); // clones a reference
2323 if let Some(module) = module {
2324 // Move down in the graph.
2325 let orig_module = replace(&mut self.current_module, module);
2326 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2327 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2329 self.finalize_current_module_macro_resolutions();
2332 self.current_module = orig_module;
2333 self.ribs[ValueNS].pop();
2334 self.ribs[TypeNS].pop();
2341 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2342 /// is returned by the given predicate function
2344 /// Stops after meeting a closure.
2345 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2346 where P: Fn(&Rib, Ident) -> Option<R>
2348 for rib in self.label_ribs.iter().rev() {
2351 // If an invocation of this macro created `ident`, give up on `ident`
2352 // and switch to `ident`'s source from the macro definition.
2353 MacroDefinition(def) => {
2354 if def == self.macro_def(ident.span.ctxt()) {
2355 ident.span.remove_mark();
2359 // Do not resolve labels across function boundary
2363 let r = pred(rib, ident);
2371 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2372 self.with_current_self_item(item, |this| {
2373 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2374 let item_def_id = this.definitions.local_def_id(item.id);
2375 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2376 visit::walk_item(this, item);
2382 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2383 let segments = &use_tree.prefix.segments;
2384 if !segments.is_empty() {
2385 let ident = segments[0].ident;
2386 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2390 let nss = match use_tree.kind {
2391 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2395 if let Some(LexicalScopeBinding::Def(..)) =
2396 self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2397 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2398 self.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2401 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2402 for (use_tree, _) in use_trees {
2403 self.future_proof_import(use_tree);
2408 fn resolve_item(&mut self, item: &Item) {
2409 let name = item.ident.name;
2410 debug!("(resolving item) resolving {}", name);
2413 ItemKind::Ty(_, ref generics) |
2414 ItemKind::Fn(_, _, ref generics, _) |
2415 ItemKind::Existential(_, ref generics) => {
2416 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2417 |this| visit::walk_item(this, item));
2420 ItemKind::Enum(_, ref generics) |
2421 ItemKind::Struct(_, ref generics) |
2422 ItemKind::Union(_, ref generics) => {
2423 self.resolve_adt(item, generics);
2426 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2427 self.resolve_implementation(generics,
2433 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2434 // Create a new rib for the trait-wide type parameters.
2435 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2436 let local_def_id = this.definitions.local_def_id(item.id);
2437 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2438 this.visit_generics(generics);
2439 walk_list!(this, visit_param_bound, bounds);
2441 for trait_item in trait_items {
2442 let type_parameters = HasTypeParameters(&trait_item.generics,
2443 TraitOrImplItemRibKind);
2444 this.with_type_parameter_rib(type_parameters, |this| {
2445 match trait_item.node {
2446 TraitItemKind::Const(ref ty, ref default) => {
2449 // Only impose the restrictions of
2450 // ConstRibKind for an actual constant
2451 // expression in a provided default.
2452 if let Some(ref expr) = *default{
2453 this.with_constant_rib(|this| {
2454 this.visit_expr(expr);
2458 TraitItemKind::Method(_, _) => {
2459 visit::walk_trait_item(this, trait_item)
2461 TraitItemKind::Type(..) => {
2462 visit::walk_trait_item(this, trait_item)
2464 TraitItemKind::Macro(_) => {
2465 panic!("unexpanded macro in resolve!")
2474 ItemKind::TraitAlias(ref generics, ref bounds) => {
2475 // Create a new rib for the trait-wide type parameters.
2476 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2477 let local_def_id = this.definitions.local_def_id(item.id);
2478 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2479 this.visit_generics(generics);
2480 walk_list!(this, visit_param_bound, bounds);
2485 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2486 self.with_scope(item.id, |this| {
2487 visit::walk_item(this, item);
2491 ItemKind::Static(ref ty, _, ref expr) |
2492 ItemKind::Const(ref ty, ref expr) => {
2493 self.with_item_rib(|this| {
2495 this.with_constant_rib(|this| {
2496 this.visit_expr(expr);
2501 ItemKind::Use(ref use_tree) => {
2502 self.future_proof_import(use_tree);
2505 ItemKind::ExternCrate(..) |
2506 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2507 // do nothing, these are just around to be encoded
2510 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2514 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2515 where F: FnOnce(&mut Resolver)
2517 match type_parameters {
2518 HasTypeParameters(generics, rib_kind) => {
2519 let mut function_type_rib = Rib::new(rib_kind);
2520 let mut seen_bindings = FxHashMap::default();
2521 for param in &generics.params {
2523 GenericParamKind::Lifetime { .. } => {}
2524 GenericParamKind::Type { .. } => {
2525 let ident = param.ident.modern();
2526 debug!("with_type_parameter_rib: {}", param.id);
2528 if seen_bindings.contains_key(&ident) {
2529 let span = seen_bindings.get(&ident).unwrap();
2530 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2534 resolve_error(self, param.ident.span, err);
2536 seen_bindings.entry(ident).or_insert(param.ident.span);
2538 // Plain insert (no renaming).
2539 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2540 function_type_rib.bindings.insert(ident, def);
2541 self.record_def(param.id, PathResolution::new(def));
2545 self.ribs[TypeNS].push(function_type_rib);
2548 NoTypeParameters => {
2555 if let HasTypeParameters(..) = type_parameters {
2556 self.ribs[TypeNS].pop();
2560 fn with_label_rib<F>(&mut self, f: F)
2561 where F: FnOnce(&mut Resolver)
2563 self.label_ribs.push(Rib::new(NormalRibKind));
2565 self.label_ribs.pop();
2568 fn with_item_rib<F>(&mut self, f: F)
2569 where F: FnOnce(&mut Resolver)
2571 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2572 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2574 self.ribs[TypeNS].pop();
2575 self.ribs[ValueNS].pop();
2578 fn with_constant_rib<F>(&mut self, f: F)
2579 where F: FnOnce(&mut Resolver)
2581 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2582 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2584 self.label_ribs.pop();
2585 self.ribs[ValueNS].pop();
2588 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2589 where F: FnOnce(&mut Resolver) -> T
2591 // Handle nested impls (inside fn bodies)
2592 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2593 let result = f(self);
2594 self.current_self_type = previous_value;
2598 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2599 where F: FnOnce(&mut Resolver) -> T
2601 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2602 let result = f(self);
2603 self.current_self_item = previous_value;
2607 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2608 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2609 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2611 let mut new_val = None;
2612 let mut new_id = None;
2613 if let Some(trait_ref) = opt_trait_ref {
2614 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2615 let def = self.smart_resolve_path_fragment(
2619 trait_ref.path.span,
2620 PathSource::Trait(AliasPossibility::No),
2621 CrateLint::SimplePath(trait_ref.ref_id),
2623 if def != Def::Err {
2624 new_id = Some(def.def_id());
2625 let span = trait_ref.path.span;
2626 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2627 self.resolve_path_without_parent_scope(
2632 CrateLint::SimplePath(trait_ref.ref_id),
2635 new_val = Some((module, trait_ref.clone()));
2639 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2640 let result = f(self, new_id);
2641 self.current_trait_ref = original_trait_ref;
2645 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2646 where F: FnOnce(&mut Resolver)
2648 let mut self_type_rib = Rib::new(NormalRibKind);
2650 // plain insert (no renaming, types are not currently hygienic....)
2651 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2652 self.ribs[TypeNS].push(self_type_rib);
2654 self.ribs[TypeNS].pop();
2657 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2658 where F: FnOnce(&mut Resolver)
2660 let self_def = Def::SelfCtor(impl_id);
2661 let mut self_type_rib = Rib::new(NormalRibKind);
2662 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2663 self.ribs[ValueNS].push(self_type_rib);
2665 self.ribs[ValueNS].pop();
2668 fn resolve_implementation(&mut self,
2669 generics: &Generics,
2670 opt_trait_reference: &Option<TraitRef>,
2673 impl_items: &[ImplItem]) {
2674 // If applicable, create a rib for the type parameters.
2675 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2676 // Dummy self type for better errors if `Self` is used in the trait path.
2677 this.with_self_rib(Def::SelfTy(None, None), |this| {
2678 // Resolve the trait reference, if necessary.
2679 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2680 let item_def_id = this.definitions.local_def_id(item_id);
2681 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2682 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2683 // Resolve type arguments in the trait path.
2684 visit::walk_trait_ref(this, trait_ref);
2686 // Resolve the self type.
2687 this.visit_ty(self_type);
2688 // Resolve the type parameters.
2689 this.visit_generics(generics);
2690 // Resolve the items within the impl.
2691 this.with_current_self_type(self_type, |this| {
2692 this.with_self_struct_ctor_rib(item_def_id, |this| {
2693 for impl_item in impl_items {
2694 this.resolve_visibility(&impl_item.vis);
2696 // We also need a new scope for the impl item type parameters.
2697 let type_parameters = HasTypeParameters(&impl_item.generics,
2698 TraitOrImplItemRibKind);
2699 this.with_type_parameter_rib(type_parameters, |this| {
2700 use self::ResolutionError::*;
2701 match impl_item.node {
2702 ImplItemKind::Const(..) => {
2703 // If this is a trait impl, ensure the const
2705 this.check_trait_item(impl_item.ident,
2708 |n, s| ConstNotMemberOfTrait(n, s));
2709 this.with_constant_rib(|this|
2710 visit::walk_impl_item(this, impl_item)
2713 ImplItemKind::Method(..) => {
2714 // If this is a trait impl, ensure the method
2716 this.check_trait_item(impl_item.ident,
2719 |n, s| MethodNotMemberOfTrait(n, s));
2721 visit::walk_impl_item(this, impl_item);
2723 ImplItemKind::Type(ref ty) => {
2724 // If this is a trait impl, ensure the type
2726 this.check_trait_item(impl_item.ident,
2729 |n, s| TypeNotMemberOfTrait(n, s));
2733 ImplItemKind::Existential(ref bounds) => {
2734 // If this is a trait impl, ensure the type
2736 this.check_trait_item(impl_item.ident,
2739 |n, s| TypeNotMemberOfTrait(n, s));
2741 for bound in bounds {
2742 this.visit_param_bound(bound);
2745 ImplItemKind::Macro(_) =>
2746 panic!("unexpanded macro in resolve!"),
2758 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2759 where F: FnOnce(Name, &str) -> ResolutionError
2761 // If there is a TraitRef in scope for an impl, then the method must be in the
2763 if let Some((module, _)) = self.current_trait_ref {
2764 if self.resolve_ident_in_module(
2765 ModuleOrUniformRoot::Module(module),
2772 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2773 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2778 fn resolve_local(&mut self, local: &Local) {
2779 // Resolve the type.
2780 walk_list!(self, visit_ty, &local.ty);
2782 // Resolve the initializer.
2783 walk_list!(self, visit_expr, &local.init);
2785 // Resolve the pattern.
2786 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2789 // build a map from pattern identifiers to binding-info's.
2790 // this is done hygienically. This could arise for a macro
2791 // that expands into an or-pattern where one 'x' was from the
2792 // user and one 'x' came from the macro.
2793 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2794 let mut binding_map = FxHashMap::default();
2796 pat.walk(&mut |pat| {
2797 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2798 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2799 Some(Def::Local(..)) => true,
2802 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2803 binding_map.insert(ident, binding_info);
2812 // check that all of the arms in an or-pattern have exactly the
2813 // same set of bindings, with the same binding modes for each.
2814 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2815 if pats.is_empty() {
2819 let mut missing_vars = FxHashMap::default();
2820 let mut inconsistent_vars = FxHashMap::default();
2821 for (i, p) in pats.iter().enumerate() {
2822 let map_i = self.binding_mode_map(&p);
2824 for (j, q) in pats.iter().enumerate() {
2829 let map_j = self.binding_mode_map(&q);
2830 for (&key, &binding_i) in &map_i {
2831 if map_j.is_empty() { // Account for missing bindings when
2832 let binding_error = missing_vars // map_j has none.
2834 .or_insert(BindingError {
2836 origin: BTreeSet::new(),
2837 target: BTreeSet::new(),
2839 binding_error.origin.insert(binding_i.span);
2840 binding_error.target.insert(q.span);
2842 for (&key_j, &binding_j) in &map_j {
2843 match map_i.get(&key_j) {
2844 None => { // missing binding
2845 let binding_error = missing_vars
2847 .or_insert(BindingError {
2849 origin: BTreeSet::new(),
2850 target: BTreeSet::new(),
2852 binding_error.origin.insert(binding_j.span);
2853 binding_error.target.insert(p.span);
2855 Some(binding_i) => { // check consistent binding
2856 if binding_i.binding_mode != binding_j.binding_mode {
2859 .or_insert((binding_j.span, binding_i.span));
2867 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2868 missing_vars.sort();
2869 for (_, v) in missing_vars {
2871 *v.origin.iter().next().unwrap(),
2872 ResolutionError::VariableNotBoundInPattern(v));
2874 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2875 inconsistent_vars.sort();
2876 for (name, v) in inconsistent_vars {
2877 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2881 fn resolve_arm(&mut self, arm: &Arm) {
2882 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2884 let mut bindings_list = FxHashMap::default();
2885 for pattern in &arm.pats {
2886 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2889 // This has to happen *after* we determine which pat_idents are variants.
2890 self.check_consistent_bindings(&arm.pats);
2892 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2893 self.visit_expr(expr)
2895 self.visit_expr(&arm.body);
2897 self.ribs[ValueNS].pop();
2900 fn resolve_block(&mut self, block: &Block) {
2901 debug!("(resolving block) entering block");
2902 // Move down in the graph, if there's an anonymous module rooted here.
2903 let orig_module = self.current_module;
2904 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2906 let mut num_macro_definition_ribs = 0;
2907 if let Some(anonymous_module) = anonymous_module {
2908 debug!("(resolving block) found anonymous module, moving down");
2909 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2910 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2911 self.current_module = anonymous_module;
2912 self.finalize_current_module_macro_resolutions();
2914 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2917 // Descend into the block.
2918 for stmt in &block.stmts {
2919 if let ast::StmtKind::Item(ref item) = stmt.node {
2920 if let ast::ItemKind::MacroDef(..) = item.node {
2921 num_macro_definition_ribs += 1;
2922 let def = self.definitions.local_def_id(item.id);
2923 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2924 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2928 self.visit_stmt(stmt);
2932 self.current_module = orig_module;
2933 for _ in 0 .. num_macro_definition_ribs {
2934 self.ribs[ValueNS].pop();
2935 self.label_ribs.pop();
2937 self.ribs[ValueNS].pop();
2938 if anonymous_module.is_some() {
2939 self.ribs[TypeNS].pop();
2941 debug!("(resolving block) leaving block");
2944 fn fresh_binding(&mut self,
2947 outer_pat_id: NodeId,
2948 pat_src: PatternSource,
2949 bindings: &mut FxHashMap<Ident, NodeId>)
2951 // Add the binding to the local ribs, if it
2952 // doesn't already exist in the bindings map. (We
2953 // must not add it if it's in the bindings map
2954 // because that breaks the assumptions later
2955 // passes make about or-patterns.)
2956 let ident = ident.modern_and_legacy();
2957 let mut def = Def::Local(pat_id);
2958 match bindings.get(&ident).cloned() {
2959 Some(id) if id == outer_pat_id => {
2960 // `Variant(a, a)`, error
2964 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2968 Some(..) if pat_src == PatternSource::FnParam => {
2969 // `fn f(a: u8, a: u8)`, error
2973 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2977 Some(..) if pat_src == PatternSource::Match ||
2978 pat_src == PatternSource::IfLet ||
2979 pat_src == PatternSource::WhileLet => {
2980 // `Variant1(a) | Variant2(a)`, ok
2981 // Reuse definition from the first `a`.
2982 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2985 span_bug!(ident.span, "two bindings with the same name from \
2986 unexpected pattern source {:?}", pat_src);
2989 // A completely fresh binding, add to the lists if it's valid.
2990 if ident.name != keywords::Invalid.name() {
2991 bindings.insert(ident, outer_pat_id);
2992 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2997 PathResolution::new(def)
3000 fn resolve_pattern(&mut self,
3002 pat_src: PatternSource,
3003 // Maps idents to the node ID for the
3004 // outermost pattern that binds them.
3005 bindings: &mut FxHashMap<Ident, NodeId>) {
3006 // Visit all direct subpatterns of this pattern.
3007 let outer_pat_id = pat.id;
3008 pat.walk(&mut |pat| {
3009 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3011 PatKind::Ident(bmode, ident, ref opt_pat) => {
3012 // First try to resolve the identifier as some existing
3013 // entity, then fall back to a fresh binding.
3014 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3016 .and_then(LexicalScopeBinding::item);
3017 let resolution = binding.map(NameBinding::def).and_then(|def| {
3018 let is_syntactic_ambiguity = opt_pat.is_none() &&
3019 bmode == BindingMode::ByValue(Mutability::Immutable);
3021 Def::StructCtor(_, CtorKind::Const) |
3022 Def::VariantCtor(_, CtorKind::Const) |
3023 Def::Const(..) if is_syntactic_ambiguity => {
3024 // Disambiguate in favor of a unit struct/variant
3025 // or constant pattern.
3026 self.record_use(ident, ValueNS, binding.unwrap(), false);
3027 Some(PathResolution::new(def))
3029 Def::StructCtor(..) | Def::VariantCtor(..) |
3030 Def::Const(..) | Def::Static(..) => {
3031 // This is unambiguously a fresh binding, either syntactically
3032 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3033 // to something unusable as a pattern (e.g., constructor function),
3034 // but we still conservatively report an error, see
3035 // issues/33118#issuecomment-233962221 for one reason why.
3039 ResolutionError::BindingShadowsSomethingUnacceptable(
3040 pat_src.descr(), ident.name, binding.unwrap())
3044 Def::Fn(..) | Def::Err => {
3045 // These entities are explicitly allowed
3046 // to be shadowed by fresh bindings.
3050 span_bug!(ident.span, "unexpected definition for an \
3051 identifier in pattern: {:?}", def);
3054 }).unwrap_or_else(|| {
3055 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3058 self.record_def(pat.id, resolution);
3061 PatKind::TupleStruct(ref path, ..) => {
3062 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3065 PatKind::Path(ref qself, ref path) => {
3066 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3069 PatKind::Struct(ref path, ..) => {
3070 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3078 visit::walk_pat(self, pat);
3081 // High-level and context dependent path resolution routine.
3082 // Resolves the path and records the resolution into definition map.
3083 // If resolution fails tries several techniques to find likely
3084 // resolution candidates, suggest imports or other help, and report
3085 // errors in user friendly way.
3086 fn smart_resolve_path(&mut self,
3088 qself: Option<&QSelf>,
3092 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3095 /// A variant of `smart_resolve_path` where you also specify extra
3096 /// information about where the path came from; this extra info is
3097 /// sometimes needed for the lint that recommends rewriting
3098 /// absolute paths to `crate`, so that it knows how to frame the
3099 /// suggestion. If you are just resolving a path like `foo::bar`
3100 /// that appears...somewhere, though, then you just want
3101 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3102 /// already provides.
3103 fn smart_resolve_path_with_crate_lint(
3106 qself: Option<&QSelf>,
3109 crate_lint: CrateLint
3110 ) -> PathResolution {
3111 self.smart_resolve_path_fragment(
3114 &Segment::from_path(path),
3121 fn smart_resolve_path_fragment(&mut self,
3123 qself: Option<&QSelf>,
3127 crate_lint: CrateLint)
3129 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3130 let ns = source.namespace();
3131 let is_expected = &|def| source.is_expected(def);
3132 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3134 // Base error is amended with one short label and possibly some longer helps/notes.
3135 let report_errors = |this: &mut Self, def: Option<Def>| {
3136 // Make the base error.
3137 let expected = source.descr_expected();
3138 let path_str = Segment::names_to_string(path);
3139 let item_str = path.last().unwrap().ident;
3140 let code = source.error_code(def.is_some());
3141 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3142 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3143 format!("not a {}", expected),
3146 let item_span = path.last().unwrap().ident.span;
3147 let (mod_prefix, mod_str) = if path.len() == 1 {
3148 (String::new(), "this scope".to_string())
3149 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3150 (String::new(), "the crate root".to_string())
3152 let mod_path = &path[..path.len() - 1];
3153 let mod_prefix = match this.resolve_path_without_parent_scope(
3154 mod_path, Some(TypeNS), false, span, CrateLint::No
3156 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3159 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3160 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3162 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3163 format!("not found in {}", mod_str),
3167 let code = DiagnosticId::Error(code.into());
3168 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3170 // Emit help message for fake-self from other languages like `this`(javascript)
3171 if ["this", "my"].contains(&&*item_str.as_str())
3172 && this.self_value_is_available(path[0].ident.span, span) {
3173 err.span_suggestion_with_applicability(
3177 Applicability::MaybeIncorrect,
3181 // Emit special messages for unresolved `Self` and `self`.
3182 if is_self_type(path, ns) {
3183 __diagnostic_used!(E0411);
3184 err.code(DiagnosticId::Error("E0411".into()));
3185 err.span_label(span, format!("`Self` is only available in impls, traits, \
3186 and type definitions"));
3187 return (err, Vec::new());
3189 if is_self_value(path, ns) {
3190 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3192 __diagnostic_used!(E0424);
3193 err.code(DiagnosticId::Error("E0424".into()));
3194 err.span_label(span, match source {
3195 PathSource::Pat => {
3196 format!("`self` value is a keyword \
3197 and may not be bound to \
3198 variables or shadowed")
3201 format!("`self` value is a keyword \
3202 only available in methods \
3203 with `self` parameter")
3206 return (err, Vec::new());
3209 // Try to lookup the name in more relaxed fashion for better error reporting.
3210 let ident = path.last().unwrap().ident;
3211 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3212 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3213 let enum_candidates =
3214 this.lookup_import_candidates(ident, ns, is_enum_variant);
3215 let mut enum_candidates = enum_candidates.iter()
3216 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3217 enum_candidates.sort();
3218 for (sp, variant_path, enum_path) in enum_candidates {
3220 let msg = format!("there is an enum variant `{}`, \
3226 err.span_suggestion_with_applicability(
3228 "you can try using the variant's enum",
3230 Applicability::MachineApplicable,
3235 if path.len() == 1 && this.self_type_is_available(span) {
3236 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3237 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3239 AssocSuggestion::Field => {
3240 err.span_suggestion_with_applicability(
3243 format!("self.{}", path_str),
3244 Applicability::MachineApplicable,
3246 if !self_is_available {
3247 err.span_label(span, format!("`self` value is a keyword \
3249 methods with `self` parameter"));
3252 AssocSuggestion::MethodWithSelf if self_is_available => {
3253 err.span_suggestion_with_applicability(
3256 format!("self.{}", path_str),
3257 Applicability::MachineApplicable,
3260 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3261 err.span_suggestion_with_applicability(
3264 format!("Self::{}", path_str),
3265 Applicability::MachineApplicable,
3269 return (err, candidates);
3273 let mut levenshtein_worked = false;
3275 // Try Levenshtein algorithm.
3276 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3277 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3278 levenshtein_worked = true;
3281 // Try context dependent help if relaxed lookup didn't work.
3282 if let Some(def) = def {
3283 match (def, source) {
3284 (Def::Macro(..), _) => {
3285 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3286 return (err, candidates);
3288 (Def::TyAlias(..), PathSource::Trait(_)) => {
3289 err.span_label(span, "type aliases cannot be used as traits");
3290 if nightly_options::is_nightly_build() {
3291 err.note("did you mean to use a trait alias?");
3293 return (err, candidates);
3295 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3296 ExprKind::Field(_, ident) => {
3297 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3299 return (err, candidates);
3301 ExprKind::MethodCall(ref segment, ..) => {
3302 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3303 path_str, segment.ident));
3304 return (err, candidates);
3308 (Def::Enum(..), PathSource::TupleStruct)
3309 | (Def::Enum(..), PathSource::Expr(..)) => {
3310 if let Some(variants) = this.collect_enum_variants(def) {
3311 err.note(&format!("did you mean to use one \
3312 of the following variants?\n{}",
3314 .map(|suggestion| path_names_to_string(suggestion))
3315 .map(|suggestion| format!("- `{}`", suggestion))
3316 .collect::<Vec<_>>()
3320 err.note("did you mean to use one of the enum's variants?");
3322 return (err, candidates);
3324 (Def::Struct(def_id), _) if ns == ValueNS => {
3325 if let Some((ctor_def, ctor_vis))
3326 = this.struct_constructors.get(&def_id).cloned() {
3327 let accessible_ctor = this.is_accessible(ctor_vis);
3328 if is_expected(ctor_def) && !accessible_ctor {
3329 err.span_label(span, format!("constructor is not visible \
3330 here due to private fields"));
3333 // HACK(estebank): find a better way to figure out that this was a
3334 // parser issue where a struct literal is being used on an expression
3335 // where a brace being opened means a block is being started. Look
3336 // ahead for the next text to see if `span` is followed by a `{`.
3337 let sm = this.session.source_map();
3340 sp = sm.next_point(sp);
3341 match sm.span_to_snippet(sp) {
3342 Ok(ref snippet) => {
3343 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3350 let followed_by_brace = match sm.span_to_snippet(sp) {
3351 Ok(ref snippet) if snippet == "{" => true,
3355 PathSource::Expr(Some(parent)) => {
3357 ExprKind::MethodCall(ref path_assignment, _) => {
3358 err.span_suggestion_with_applicability(
3359 sm.start_point(parent.span)
3360 .to(path_assignment.ident.span),
3361 "use `::` to access an associated function",
3364 path_assignment.ident),
3365 Applicability::MaybeIncorrect
3367 return (err, candidates);
3372 format!("did you mean `{} {{ /* fields */ }}`?",
3375 return (err, candidates);
3379 PathSource::Expr(None) if followed_by_brace == true => {
3382 format!("did you mean `({} {{ /* fields */ }})`?",
3385 return (err, candidates);
3390 format!("did you mean `{} {{ /* fields */ }}`?",
3393 return (err, candidates);
3397 return (err, candidates);
3399 (Def::Union(..), _) |
3400 (Def::Variant(..), _) |
3401 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3402 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3404 return (err, candidates);
3406 (Def::SelfTy(..), _) if ns == ValueNS => {
3407 err.span_label(span, fallback_label);
3408 err.note("can't use `Self` as a constructor, you must use the \
3409 implemented struct");
3410 return (err, candidates);
3412 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3413 err.note("can't use a type alias as a constructor");
3414 return (err, candidates);
3421 if !levenshtein_worked {
3422 err.span_label(base_span, fallback_label);
3423 this.type_ascription_suggestion(&mut err, base_span);
3427 let report_errors = |this: &mut Self, def: Option<Def>| {
3428 let (err, candidates) = report_errors(this, def);
3429 let def_id = this.current_module.normal_ancestor_id;
3430 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3431 let better = def.is_some();
3432 this.use_injections.push(UseError { err, candidates, node_id, better });
3433 err_path_resolution()
3436 let resolution = match self.resolve_qpath_anywhere(
3442 source.defer_to_typeck(),
3443 source.global_by_default(),
3446 Some(resolution) if resolution.unresolved_segments() == 0 => {
3447 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3450 // Add a temporary hack to smooth the transition to new struct ctor
3451 // visibility rules. See #38932 for more details.
3453 if let Def::Struct(def_id) = resolution.base_def() {
3454 if let Some((ctor_def, ctor_vis))
3455 = self.struct_constructors.get(&def_id).cloned() {
3456 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3457 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3458 self.session.buffer_lint(lint, id, span,
3459 "private struct constructors are not usable through \
3460 re-exports in outer modules",
3462 res = Some(PathResolution::new(ctor_def));
3467 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3470 Some(resolution) if source.defer_to_typeck() => {
3471 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3472 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3473 // it needs to be added to the trait map.
3475 let item_name = path.last().unwrap().ident;
3476 let traits = self.get_traits_containing_item(item_name, ns);
3477 self.trait_map.insert(id, traits);
3481 _ => report_errors(self, None)
3484 if let PathSource::TraitItem(..) = source {} else {
3485 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3486 self.record_def(id, resolution);
3491 fn type_ascription_suggestion(&self,
3492 err: &mut DiagnosticBuilder,
3494 debug!("type_ascription_suggetion {:?}", base_span);
3495 let cm = self.session.source_map();
3496 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3497 if let Some(sp) = self.current_type_ascription.last() {
3499 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3500 sp = cm.next_point(sp);
3501 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3502 debug!("snippet {:?}", snippet);
3503 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3504 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3505 debug!("{:?} {:?}", line_sp, line_base_sp);
3507 err.span_label(base_span,
3508 "expecting a type here because of type ascription");
3509 if line_sp != line_base_sp {
3510 err.span_suggestion_short_with_applicability(
3512 "did you mean to use `;` here instead?",
3514 Applicability::MaybeIncorrect,
3518 } else if !snippet.trim().is_empty() {
3519 debug!("tried to find type ascription `:` token, couldn't find it");
3529 fn self_type_is_available(&mut self, span: Span) -> bool {
3530 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3531 TypeNS, None, span);
3532 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3535 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3536 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3537 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3538 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3541 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3542 fn resolve_qpath_anywhere(&mut self,
3544 qself: Option<&QSelf>,
3546 primary_ns: Namespace,
3548 defer_to_typeck: bool,
3549 global_by_default: bool,
3550 crate_lint: CrateLint)
3551 -> Option<PathResolution> {
3552 let mut fin_res = None;
3553 // FIXME: can't resolve paths in macro namespace yet, macros are
3554 // processed by the little special hack below.
3555 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3556 if i == 0 || ns != primary_ns {
3557 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3558 // If defer_to_typeck, then resolution > no resolution,
3559 // otherwise full resolution > partial resolution > no resolution.
3560 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3562 res => if fin_res.is_none() { fin_res = res },
3566 if primary_ns != MacroNS &&
3567 (self.macro_names.contains(&path[0].ident.modern()) ||
3568 self.builtin_macros.get(&path[0].ident.name).cloned()
3569 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3570 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3571 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3572 // Return some dummy definition, it's enough for error reporting.
3574 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3580 /// Handles paths that may refer to associated items.
3581 fn resolve_qpath(&mut self,
3583 qself: Option<&QSelf>,
3587 global_by_default: bool,
3588 crate_lint: CrateLint)
3589 -> Option<PathResolution> {
3591 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3592 ns={:?}, span={:?}, global_by_default={:?})",
3601 if let Some(qself) = qself {
3602 if qself.position == 0 {
3603 // This is a case like `<T>::B`, where there is no
3604 // trait to resolve. In that case, we leave the `B`
3605 // segment to be resolved by type-check.
3606 return Some(PathResolution::with_unresolved_segments(
3607 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3611 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3613 // Currently, `path` names the full item (`A::B::C`, in
3614 // our example). so we extract the prefix of that that is
3615 // the trait (the slice upto and including
3616 // `qself.position`). And then we recursively resolve that,
3617 // but with `qself` set to `None`.
3619 // However, setting `qself` to none (but not changing the
3620 // span) loses the information about where this path
3621 // *actually* appears, so for the purposes of the crate
3622 // lint we pass along information that this is the trait
3623 // name from a fully qualified path, and this also
3624 // contains the full span (the `CrateLint::QPathTrait`).
3625 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3626 let res = self.smart_resolve_path_fragment(
3629 &path[..=qself.position],
3631 PathSource::TraitItem(ns),
3632 CrateLint::QPathTrait {
3634 qpath_span: qself.path_span,
3638 // The remaining segments (the `C` in our example) will
3639 // have to be resolved by type-check, since that requires doing
3640 // trait resolution.
3641 return Some(PathResolution::with_unresolved_segments(
3642 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3646 let result = match self.resolve_path_without_parent_scope(
3653 PathResult::NonModule(path_res) => path_res,
3654 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3655 PathResolution::new(module.def().unwrap())
3657 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3658 // don't report an error right away, but try to fallback to a primitive type.
3659 // So, we are still able to successfully resolve something like
3661 // use std::u8; // bring module u8 in scope
3662 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3663 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3664 // // not to non-existent std::u8::max_value
3667 // Such behavior is required for backward compatibility.
3668 // The same fallback is used when `a` resolves to nothing.
3669 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3670 PathResult::Failed(..)
3671 if (ns == TypeNS || path.len() > 1) &&
3672 self.primitive_type_table.primitive_types
3673 .contains_key(&path[0].ident.name) => {
3674 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3675 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3677 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3678 PathResolution::new(module.def().unwrap()),
3679 PathResult::Failed(span, msg, false) => {
3680 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3681 err_path_resolution()
3683 PathResult::Module(..) | PathResult::Failed(..) => return None,
3684 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3687 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3688 path[0].ident.name != keywords::PathRoot.name() &&
3689 path[0].ident.name != keywords::DollarCrate.name() {
3690 let unqualified_result = {
3691 match self.resolve_path_without_parent_scope(
3692 &[*path.last().unwrap()],
3698 PathResult::NonModule(path_res) => path_res.base_def(),
3699 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3700 module.def().unwrap(),
3701 _ => return Some(result),
3704 if result.base_def() == unqualified_result {
3705 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3706 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3713 fn resolve_path_without_parent_scope(
3716 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3719 crate_lint: CrateLint,
3720 ) -> PathResult<'a> {
3721 // Macro and import paths must have full parent scope available during resolution,
3722 // other paths will do okay with parent module alone.
3723 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3724 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3725 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3731 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3732 parent_scope: &ParentScope<'a>,
3735 crate_lint: CrateLint,
3736 ) -> PathResult<'a> {
3737 let mut module = None;
3738 let mut allow_super = true;
3739 let mut second_binding = None;
3740 self.current_module = parent_scope.module;
3743 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3744 path_span={:?}, crate_lint={:?})",
3752 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3753 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3754 let record_segment_def = |this: &mut Self, def| {
3756 if let Some(id) = id {
3757 if !this.def_map.contains_key(&id) {
3758 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3759 this.record_def(id, PathResolution::new(def));
3765 let is_last = i == path.len() - 1;
3766 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3767 let name = ident.name;
3769 allow_super &= ns == TypeNS &&
3770 (name == keywords::SelfLower.name() ||
3771 name == keywords::Super.name());
3774 if allow_super && name == keywords::Super.name() {
3775 let mut ctxt = ident.span.ctxt().modern();
3776 let self_module = match i {
3777 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3779 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3783 if let Some(self_module) = self_module {
3784 if let Some(parent) = self_module.parent {
3785 module = Some(ModuleOrUniformRoot::Module(
3786 self.resolve_self(&mut ctxt, parent)));
3790 let msg = "there are too many initial `super`s.".to_string();
3791 return PathResult::Failed(ident.span, msg, false);
3794 if name == keywords::SelfLower.name() {
3795 let mut ctxt = ident.span.ctxt().modern();
3796 module = Some(ModuleOrUniformRoot::Module(
3797 self.resolve_self(&mut ctxt, self.current_module)));
3800 if name == keywords::Extern.name() ||
3801 name == keywords::PathRoot.name() && ident.span.rust_2018() {
3802 module = Some(ModuleOrUniformRoot::ExternPrelude);
3805 if name == keywords::PathRoot.name() &&
3806 ident.span.rust_2015() && self.session.rust_2018() {
3807 // `::a::b` from 2015 macro on 2018 global edition
3808 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3811 if name == keywords::PathRoot.name() ||
3812 name == keywords::Crate.name() ||
3813 name == keywords::DollarCrate.name() {
3814 // `::a::b`, `crate::a::b` or `$crate::a::b`
3815 module = Some(ModuleOrUniformRoot::Module(
3816 self.resolve_crate_root(ident)));
3822 // Report special messages for path segment keywords in wrong positions.
3823 if ident.is_path_segment_keyword() && i != 0 {
3824 let name_str = if name == keywords::PathRoot.name() {
3825 "crate root".to_string()
3827 format!("`{}`", name)
3829 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3830 format!("global paths cannot start with {}", name_str)
3832 format!("{} in paths can only be used in start position", name_str)
3834 return PathResult::Failed(ident.span, msg, false);
3837 let binding = if let Some(module) = module {
3838 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3839 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3840 assert!(ns == TypeNS);
3841 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3842 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3843 record_used, path_span)
3845 let record_used_id =
3846 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3847 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3848 // we found a locally-imported or available item/module
3849 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3850 // we found a local variable or type param
3851 Some(LexicalScopeBinding::Def(def))
3852 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3853 record_segment_def(self, def);
3854 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3858 _ => Err(Determinacy::determined(record_used)),
3865 second_binding = Some(binding);
3867 let def = binding.def();
3868 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3869 if let Some(next_module) = binding.module() {
3870 module = Some(ModuleOrUniformRoot::Module(next_module));
3871 record_segment_def(self, def);
3872 } else if def == Def::ToolMod && i + 1 != path.len() {
3873 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3874 return PathResult::NonModule(PathResolution::new(def));
3875 } else if def == Def::Err {
3876 return PathResult::NonModule(err_path_resolution());
3877 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3878 self.lint_if_path_starts_with_module(
3884 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3885 def, path.len() - i - 1
3888 return PathResult::Failed(ident.span,
3889 format!("not a module `{}`", ident),
3893 Err(Undetermined) => return PathResult::Indeterminate,
3894 Err(Determined) => {
3895 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3896 if opt_ns.is_some() && !module.is_normal() {
3897 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3898 module.def().unwrap(), path.len() - i
3902 let module_def = match module {
3903 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3906 let msg = if module_def == self.graph_root.def() {
3907 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3908 let mut candidates =
3909 self.lookup_import_candidates(ident, TypeNS, is_mod);
3910 candidates.sort_by_cached_key(|c| {
3911 (c.path.segments.len(), c.path.to_string())
3913 if let Some(candidate) = candidates.get(0) {
3914 format!("did you mean `{}`?", candidate.path)
3916 format!("maybe a missing `extern crate {};`?", ident)
3919 format!("use of undeclared type or module `{}`", ident)
3921 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
3923 return PathResult::Failed(ident.span, msg, is_last);
3928 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3930 PathResult::Module(match module {
3931 Some(module) => module,
3932 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3933 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3937 fn lint_if_path_starts_with_module(
3939 crate_lint: CrateLint,
3942 second_binding: Option<&NameBinding>,
3944 let (diag_id, diag_span) = match crate_lint {
3945 CrateLint::No => return,
3946 CrateLint::SimplePath(id) => (id, path_span),
3947 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3948 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3951 let first_name = match path.get(0) {
3952 // In the 2018 edition this lint is a hard error, so nothing to do
3953 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3957 // We're only interested in `use` paths which should start with
3958 // `{{root}}` or `extern` currently.
3959 if first_name != keywords::Extern.name() && first_name != keywords::PathRoot.name() {
3964 // If this import looks like `crate::...` it's already good
3965 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3966 // Otherwise go below to see if it's an extern crate
3968 // If the path has length one (and it's `PathRoot` most likely)
3969 // then we don't know whether we're gonna be importing a crate or an
3970 // item in our crate. Defer this lint to elsewhere
3974 // If the first element of our path was actually resolved to an
3975 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3976 // warning, this looks all good!
3977 if let Some(binding) = second_binding {
3978 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3979 // Careful: we still want to rewrite paths from
3980 // renamed extern crates.
3981 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3987 let diag = lint::builtin::BuiltinLintDiagnostics
3988 ::AbsPathWithModule(diag_span);
3989 self.session.buffer_lint_with_diagnostic(
3990 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3992 "absolute paths must start with `self`, `super`, \
3993 `crate`, or an external crate name in the 2018 edition",
3997 // Resolve a local definition, potentially adjusting for closures.
3998 fn adjust_local_def(&mut self,
4003 span: Span) -> Def {
4004 let ribs = &self.ribs[ns][rib_index + 1..];
4006 // An invalid forward use of a type parameter from a previous default.
4007 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4009 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4011 assert_eq!(def, Def::Err);
4017 span_bug!(span, "unexpected {:?} in bindings", def)
4019 Def::Local(node_id) => {
4022 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4023 ForwardTyParamBanRibKind => {
4024 // Nothing to do. Continue.
4026 ClosureRibKind(function_id) => {
4029 let seen = self.freevars_seen
4032 if let Some(&index) = seen.get(&node_id) {
4033 def = Def::Upvar(node_id, index, function_id);
4036 let vec = self.freevars
4039 let depth = vec.len();
4040 def = Def::Upvar(node_id, depth, function_id);
4047 seen.insert(node_id, depth);
4050 ItemRibKind | TraitOrImplItemRibKind => {
4051 // This was an attempt to access an upvar inside a
4052 // named function item. This is not allowed, so we
4055 resolve_error(self, span,
4056 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4060 ConstantItemRibKind => {
4061 // Still doesn't deal with upvars
4063 resolve_error(self, span,
4064 ResolutionError::AttemptToUseNonConstantValueInConstant);
4071 Def::TyParam(..) | Def::SelfTy(..) => {
4074 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4075 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4076 ConstantItemRibKind => {
4077 // Nothing to do. Continue.
4080 // This was an attempt to use a type parameter outside
4083 resolve_error(self, span,
4084 ResolutionError::TypeParametersFromOuterFunction(def));
4096 fn lookup_assoc_candidate<FilterFn>(&mut self,
4099 filter_fn: FilterFn)
4100 -> Option<AssocSuggestion>
4101 where FilterFn: Fn(Def) -> bool
4103 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4105 TyKind::Path(None, _) => Some(t.id),
4106 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4107 // This doesn't handle the remaining `Ty` variants as they are not
4108 // that commonly the self_type, it might be interesting to provide
4109 // support for those in future.
4114 // Fields are generally expected in the same contexts as locals.
4115 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4116 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4117 // Look for a field with the same name in the current self_type.
4118 if let Some(resolution) = self.def_map.get(&node_id) {
4119 match resolution.base_def() {
4120 Def::Struct(did) | Def::Union(did)
4121 if resolution.unresolved_segments() == 0 => {
4122 if let Some(field_names) = self.field_names.get(&did) {
4123 if field_names.iter().any(|&field_name| ident.name == field_name) {
4124 return Some(AssocSuggestion::Field);
4134 // Look for associated items in the current trait.
4135 if let Some((module, _)) = self.current_trait_ref {
4136 if let Ok(binding) = self.resolve_ident_in_module(
4137 ModuleOrUniformRoot::Module(module),
4144 let def = binding.def();
4146 return Some(if self.has_self.contains(&def.def_id()) {
4147 AssocSuggestion::MethodWithSelf
4149 AssocSuggestion::AssocItem
4158 fn lookup_typo_candidate<FilterFn>(&mut self,
4161 filter_fn: FilterFn,
4164 where FilterFn: Fn(Def) -> bool
4166 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4167 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4168 if let Some(binding) = resolution.borrow().binding {
4169 if filter_fn(binding.def()) {
4170 names.push(ident.name);
4176 let mut names = Vec::new();
4177 if path.len() == 1 {
4178 // Search in lexical scope.
4179 // Walk backwards up the ribs in scope and collect candidates.
4180 for rib in self.ribs[ns].iter().rev() {
4181 // Locals and type parameters
4182 for (ident, def) in &rib.bindings {
4183 if filter_fn(*def) {
4184 names.push(ident.name);
4188 if let ModuleRibKind(module) = rib.kind {
4189 // Items from this module
4190 add_module_candidates(module, &mut names);
4192 if let ModuleKind::Block(..) = module.kind {
4193 // We can see through blocks
4195 // Items from the prelude
4196 if !module.no_implicit_prelude {
4197 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4198 if let Some(prelude) = self.prelude {
4199 add_module_candidates(prelude, &mut names);
4206 // Add primitive types to the mix
4207 if filter_fn(Def::PrimTy(Bool)) {
4209 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4213 // Search in module.
4214 let mod_path = &path[..path.len() - 1];
4215 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4216 mod_path, Some(TypeNS), false, span, CrateLint::No
4218 if let ModuleOrUniformRoot::Module(module) = module {
4219 add_module_candidates(module, &mut names);
4224 let name = path[path.len() - 1].ident.name;
4225 // Make sure error reporting is deterministic.
4226 names.sort_by_cached_key(|name| name.as_str());
4227 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4228 Some(found) if found != name => Some(found),
4233 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4234 where F: FnOnce(&mut Resolver)
4236 if let Some(label) = label {
4237 self.unused_labels.insert(id, label.ident.span);
4238 let def = Def::Label(id);
4239 self.with_label_rib(|this| {
4240 let ident = label.ident.modern_and_legacy();
4241 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4249 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4250 self.with_resolved_label(label, id, |this| this.visit_block(block));
4253 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4254 // First, record candidate traits for this expression if it could
4255 // result in the invocation of a method call.
4257 self.record_candidate_traits_for_expr_if_necessary(expr);
4259 // Next, resolve the node.
4261 ExprKind::Path(ref qself, ref path) => {
4262 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4263 visit::walk_expr(self, expr);
4266 ExprKind::Struct(ref path, ..) => {
4267 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4268 visit::walk_expr(self, expr);
4271 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4272 let def = self.search_label(label.ident, |rib, ident| {
4273 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4277 // Search again for close matches...
4278 // Picks the first label that is "close enough", which is not necessarily
4279 // the closest match
4280 let close_match = self.search_label(label.ident, |rib, ident| {
4281 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4282 find_best_match_for_name(names, &*ident.as_str(), None)
4284 self.record_def(expr.id, err_path_resolution());
4287 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4290 Some(Def::Label(id)) => {
4291 // Since this def is a label, it is never read.
4292 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4293 self.unused_labels.remove(&id);
4296 span_bug!(expr.span, "label wasn't mapped to a label def!");
4300 // visit `break` argument if any
4301 visit::walk_expr(self, expr);
4304 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4305 self.visit_expr(subexpression);
4307 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4308 let mut bindings_list = FxHashMap::default();
4310 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4312 // This has to happen *after* we determine which pat_idents are variants
4313 self.check_consistent_bindings(pats);
4314 self.visit_block(if_block);
4315 self.ribs[ValueNS].pop();
4317 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4320 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4322 ExprKind::While(ref subexpression, ref block, label) => {
4323 self.with_resolved_label(label, expr.id, |this| {
4324 this.visit_expr(subexpression);
4325 this.visit_block(block);
4329 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4330 self.with_resolved_label(label, expr.id, |this| {
4331 this.visit_expr(subexpression);
4332 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4333 let mut bindings_list = FxHashMap::default();
4335 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4337 // This has to happen *after* we determine which pat_idents are variants.
4338 this.check_consistent_bindings(pats);
4339 this.visit_block(block);
4340 this.ribs[ValueNS].pop();
4344 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4345 self.visit_expr(subexpression);
4346 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4347 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4349 self.resolve_labeled_block(label, expr.id, block);
4351 self.ribs[ValueNS].pop();
4354 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4356 // Equivalent to `visit::walk_expr` + passing some context to children.
4357 ExprKind::Field(ref subexpression, _) => {
4358 self.resolve_expr(subexpression, Some(expr));
4360 ExprKind::MethodCall(ref segment, ref arguments) => {
4361 let mut arguments = arguments.iter();
4362 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4363 for argument in arguments {
4364 self.resolve_expr(argument, None);
4366 self.visit_path_segment(expr.span, segment);
4369 ExprKind::Call(ref callee, ref arguments) => {
4370 self.resolve_expr(callee, Some(expr));
4371 for argument in arguments {
4372 self.resolve_expr(argument, None);
4375 ExprKind::Type(ref type_expr, _) => {
4376 self.current_type_ascription.push(type_expr.span);
4377 visit::walk_expr(self, expr);
4378 self.current_type_ascription.pop();
4380 // Resolve the body of async exprs inside the async closure to which they desugar
4381 ExprKind::Async(_, async_closure_id, ref block) => {
4382 let rib_kind = ClosureRibKind(async_closure_id);
4383 self.ribs[ValueNS].push(Rib::new(rib_kind));
4384 self.label_ribs.push(Rib::new(rib_kind));
4385 self.visit_block(&block);
4386 self.label_ribs.pop();
4387 self.ribs[ValueNS].pop();
4389 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4390 // resolve the arguments within the proper scopes so that usages of them inside the
4391 // closure are detected as upvars rather than normal closure arg usages.
4393 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4394 ref fn_decl, ref body, _span,
4396 let rib_kind = ClosureRibKind(expr.id);
4397 self.ribs[ValueNS].push(Rib::new(rib_kind));
4398 self.label_ribs.push(Rib::new(rib_kind));
4399 // Resolve arguments:
4400 let mut bindings_list = FxHashMap::default();
4401 for argument in &fn_decl.inputs {
4402 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4403 self.visit_ty(&argument.ty);
4405 // No need to resolve return type-- the outer closure return type is
4406 // FunctionRetTy::Default
4408 // Now resolve the inner closure
4410 let rib_kind = ClosureRibKind(inner_closure_id);
4411 self.ribs[ValueNS].push(Rib::new(rib_kind));
4412 self.label_ribs.push(Rib::new(rib_kind));
4413 // No need to resolve arguments: the inner closure has none.
4414 // Resolve the return type:
4415 visit::walk_fn_ret_ty(self, &fn_decl.output);
4417 self.visit_expr(body);
4418 self.label_ribs.pop();
4419 self.ribs[ValueNS].pop();
4421 self.label_ribs.pop();
4422 self.ribs[ValueNS].pop();
4425 visit::walk_expr(self, expr);
4430 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4432 ExprKind::Field(_, ident) => {
4433 // FIXME(#6890): Even though you can't treat a method like a
4434 // field, we need to add any trait methods we find that match
4435 // the field name so that we can do some nice error reporting
4436 // later on in typeck.
4437 let traits = self.get_traits_containing_item(ident, ValueNS);
4438 self.trait_map.insert(expr.id, traits);
4440 ExprKind::MethodCall(ref segment, ..) => {
4441 debug!("(recording candidate traits for expr) recording traits for {}",
4443 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4444 self.trait_map.insert(expr.id, traits);
4452 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4453 -> Vec<TraitCandidate> {
4454 debug!("(getting traits containing item) looking for '{}'", ident.name);
4456 let mut found_traits = Vec::new();
4457 // Look for the current trait.
4458 if let Some((module, _)) = self.current_trait_ref {
4459 if self.resolve_ident_in_module(
4460 ModuleOrUniformRoot::Module(module),
4467 let def_id = module.def_id().unwrap();
4468 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4472 ident.span = ident.span.modern();
4473 let mut search_module = self.current_module;
4475 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4476 search_module = unwrap_or!(
4477 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4481 if let Some(prelude) = self.prelude {
4482 if !search_module.no_implicit_prelude {
4483 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4490 fn get_traits_in_module_containing_item(&mut self,
4494 found_traits: &mut Vec<TraitCandidate>) {
4495 assert!(ns == TypeNS || ns == ValueNS);
4496 let mut traits = module.traits.borrow_mut();
4497 if traits.is_none() {
4498 let mut collected_traits = Vec::new();
4499 module.for_each_child(|name, ns, binding| {
4500 if ns != TypeNS { return }
4501 if let Def::Trait(_) = binding.def() {
4502 collected_traits.push((name, binding));
4505 *traits = Some(collected_traits.into_boxed_slice());
4508 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4509 let module = binding.module().unwrap();
4510 let mut ident = ident;
4511 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4514 if self.resolve_ident_in_module_unadjusted(
4515 ModuleOrUniformRoot::Module(module),
4521 let import_id = match binding.kind {
4522 NameBindingKind::Import { directive, .. } => {
4523 self.maybe_unused_trait_imports.insert(directive.id);
4524 self.add_to_glob_map(directive.id, trait_name);
4529 let trait_def_id = module.def_id().unwrap();
4530 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4535 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4536 lookup_ident: Ident,
4537 namespace: Namespace,
4538 start_module: &'a ModuleData<'a>,
4540 filter_fn: FilterFn)
4541 -> Vec<ImportSuggestion>
4542 where FilterFn: Fn(Def) -> bool
4544 let mut candidates = Vec::new();
4545 let mut seen_modules = FxHashSet::default();
4546 let not_local_module = crate_name != keywords::Crate.ident();
4547 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4549 while let Some((in_module,
4551 in_module_is_extern)) = worklist.pop() {
4552 self.populate_module_if_necessary(in_module);
4554 // We have to visit module children in deterministic order to avoid
4555 // instabilities in reported imports (#43552).
4556 in_module.for_each_child_stable(|ident, ns, name_binding| {
4557 // avoid imports entirely
4558 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4559 // avoid non-importable candidates as well
4560 if !name_binding.is_importable() { return; }
4562 // collect results based on the filter function
4563 if ident.name == lookup_ident.name && ns == namespace {
4564 if filter_fn(name_binding.def()) {
4566 let mut segms = path_segments.clone();
4567 if lookup_ident.span.rust_2018() {
4568 // crate-local absolute paths start with `crate::` in edition 2018
4569 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4571 0, ast::PathSegment::from_ident(crate_name)
4575 segms.push(ast::PathSegment::from_ident(ident));
4577 span: name_binding.span,
4580 // the entity is accessible in the following cases:
4581 // 1. if it's defined in the same crate, it's always
4582 // accessible (since private entities can be made public)
4583 // 2. if it's defined in another crate, it's accessible
4584 // only if both the module is public and the entity is
4585 // declared as public (due to pruning, we don't explore
4586 // outside crate private modules => no need to check this)
4587 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4588 candidates.push(ImportSuggestion { path });
4593 // collect submodules to explore
4594 if let Some(module) = name_binding.module() {
4596 let mut path_segments = path_segments.clone();
4597 path_segments.push(ast::PathSegment::from_ident(ident));
4599 let is_extern_crate_that_also_appears_in_prelude =
4600 name_binding.is_extern_crate() &&
4601 lookup_ident.span.rust_2018();
4603 let is_visible_to_user =
4604 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4606 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4607 // add the module to the lookup
4608 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4609 if seen_modules.insert(module.def_id().unwrap()) {
4610 worklist.push((module, path_segments, is_extern));
4620 /// When name resolution fails, this method can be used to look up candidate
4621 /// entities with the expected name. It allows filtering them using the
4622 /// supplied predicate (which should be used to only accept the types of
4623 /// definitions expected e.g., traits). The lookup spans across all crates.
4625 /// NOTE: The method does not look into imports, but this is not a problem,
4626 /// since we report the definitions (thus, the de-aliased imports).
4627 fn lookup_import_candidates<FilterFn>(&mut self,
4628 lookup_ident: Ident,
4629 namespace: Namespace,
4630 filter_fn: FilterFn)
4631 -> Vec<ImportSuggestion>
4632 where FilterFn: Fn(Def) -> bool
4634 let mut suggestions = self.lookup_import_candidates_from_module(
4635 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4637 if lookup_ident.span.rust_2018() {
4638 let extern_prelude_names = self.extern_prelude.clone();
4639 for (ident, _) in extern_prelude_names.into_iter() {
4640 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4642 let crate_root = self.get_module(DefId {
4644 index: CRATE_DEF_INDEX,
4646 self.populate_module_if_necessary(&crate_root);
4648 suggestions.extend(self.lookup_import_candidates_from_module(
4649 lookup_ident, namespace, crate_root, ident, &filter_fn));
4657 fn find_module(&mut self,
4659 -> Option<(Module<'a>, ImportSuggestion)>
4661 let mut result = None;
4662 let mut seen_modules = FxHashSet::default();
4663 let mut worklist = vec![(self.graph_root, Vec::new())];
4665 while let Some((in_module, path_segments)) = worklist.pop() {
4666 // abort if the module is already found
4667 if result.is_some() { break; }
4669 self.populate_module_if_necessary(in_module);
4671 in_module.for_each_child_stable(|ident, _, name_binding| {
4672 // abort if the module is already found or if name_binding is private external
4673 if result.is_some() || !name_binding.vis.is_visible_locally() {
4676 if let Some(module) = name_binding.module() {
4678 let mut path_segments = path_segments.clone();
4679 path_segments.push(ast::PathSegment::from_ident(ident));
4680 if module.def() == Some(module_def) {
4682 span: name_binding.span,
4683 segments: path_segments,
4685 result = Some((module, ImportSuggestion { path }));
4687 // add the module to the lookup
4688 if seen_modules.insert(module.def_id().unwrap()) {
4689 worklist.push((module, path_segments));
4699 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4700 if let Def::Enum(..) = enum_def {} else {
4701 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4704 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4705 self.populate_module_if_necessary(enum_module);
4707 let mut variants = Vec::new();
4708 enum_module.for_each_child_stable(|ident, _, name_binding| {
4709 if let Def::Variant(..) = name_binding.def() {
4710 let mut segms = enum_import_suggestion.path.segments.clone();
4711 segms.push(ast::PathSegment::from_ident(ident));
4712 variants.push(Path {
4713 span: name_binding.span,
4722 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4723 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4724 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4725 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4729 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4731 ast::VisibilityKind::Public => ty::Visibility::Public,
4732 ast::VisibilityKind::Crate(..) => {
4733 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4735 ast::VisibilityKind::Inherited => {
4736 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4738 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4739 // For visibilities we are not ready to provide correct implementation of "uniform
4740 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4741 // On 2015 edition visibilities are resolved as crate-relative by default,
4742 // so we are prepending a root segment if necessary.
4743 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4744 let crate_root = if ident.is_path_segment_keyword() {
4746 } else if ident.span.rust_2018() {
4747 let msg = "relative paths are not supported in visibilities on 2018 edition";
4748 self.session.struct_span_err(ident.span, msg)
4749 .span_suggestion(path.span, "try", format!("crate::{}", path))
4751 return ty::Visibility::Public;
4753 let ctxt = ident.span.ctxt();
4754 Some(Segment::from_ident(Ident::new(
4755 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4759 let segments = crate_root.into_iter()
4760 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4761 let def = self.smart_resolve_path_fragment(
4766 PathSource::Visibility,
4767 CrateLint::SimplePath(id),
4769 if def == Def::Err {
4770 ty::Visibility::Public
4772 let vis = ty::Visibility::Restricted(def.def_id());
4773 if self.is_accessible(vis) {
4776 self.session.span_err(path.span, "visibilities can only be restricted \
4777 to ancestor modules");
4778 ty::Visibility::Public
4785 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4786 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4789 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4790 vis.is_accessible_from(module.normal_ancestor_id, self)
4793 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4794 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4795 if !ptr::eq(module, old_module) {
4796 span_bug!(binding.span, "parent module is reset for binding");
4801 fn disambiguate_legacy_vs_modern(
4803 legacy: &'a NameBinding<'a>,
4804 modern: &'a NameBinding<'a>,
4806 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4807 // is disambiguated to mitigate regressions from macro modularization.
4808 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4809 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4810 self.binding_parent_modules.get(&PtrKey(modern))) {
4811 (Some(legacy), Some(modern)) =>
4812 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4813 modern.is_ancestor_of(legacy),
4818 fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
4819 if b.span.is_dummy() {
4820 let add_built_in = match b.def() {
4821 // These already contain the "built-in" prefix or look bad with it.
4822 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4825 let (built_in, from) = if from_prelude {
4826 ("", " from prelude")
4827 } else if b.is_extern_crate() && !b.is_import() &&
4828 self.session.opts.externs.get(&ident.as_str()).is_some() {
4829 ("", " passed with `--extern`")
4830 } else if add_built_in {
4836 let article = if built_in.is_empty() { b.article() } else { "a" };
4837 format!("{a}{built_in} {thing}{from}",
4838 a = article, thing = b.descr(), built_in = built_in, from = from)
4840 let introduced = if b.is_import() { "imported" } else { "defined" };
4841 format!("the {thing} {introduced} here",
4842 thing = b.descr(), introduced = introduced)
4846 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
4847 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4848 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4849 // We have to print the span-less alternative first, otherwise formatting looks bad.
4850 (b2, b1, misc2, misc1, true)
4852 (b1, b2, misc1, misc2, false)
4855 let mut err = struct_span_err!(self.session, ident.span, E0659,
4856 "`{ident}` is ambiguous ({why})",
4857 ident = ident, why = kind.descr());
4858 err.span_label(ident.span, "ambiguous name");
4860 let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
4861 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4862 let note_msg = format!("`{ident}` could{also} refer to {what}",
4863 ident = ident, also = also, what = what);
4865 let mut help_msgs = Vec::new();
4866 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4867 kind == AmbiguityKind::GlobVsExpanded ||
4868 kind == AmbiguityKind::GlobVsOuter &&
4869 swapped != also.is_empty()) {
4870 help_msgs.push(format!("consider adding an explicit import of \
4871 `{ident}` to disambiguate", ident = ident))
4873 if b.is_extern_crate() && ident.span.rust_2018() {
4874 help_msgs.push(format!(
4875 "use `::{ident}` to refer to this {thing} unambiguously",
4876 ident = ident, thing = b.descr(),
4879 if misc == AmbiguityErrorMisc::SuggestCrate {
4880 help_msgs.push(format!(
4881 "use `crate::{ident}` to refer to this {thing} unambiguously",
4882 ident = ident, thing = b.descr(),
4884 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4885 help_msgs.push(format!(
4886 "use `self::{ident}` to refer to this {thing} unambiguously",
4887 ident = ident, thing = b.descr(),
4891 if b.span.is_dummy() {
4892 err.note(¬e_msg);
4894 err.span_note(b.span, ¬e_msg);
4896 for (i, help_msg) in help_msgs.iter().enumerate() {
4897 let or = if i == 0 { "" } else { "or " };
4898 err.help(&format!("{}{}", or, help_msg));
4902 could_refer_to(b1, misc1, "");
4903 could_refer_to(b2, misc2, " also");
4907 fn report_errors(&mut self, krate: &Crate) {
4908 self.report_with_use_injections(krate);
4910 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4911 let msg = "macro-expanded `macro_export` macros from the current crate \
4912 cannot be referred to by absolute paths";
4913 self.session.buffer_lint_with_diagnostic(
4914 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4915 CRATE_NODE_ID, span_use, msg,
4916 lint::builtin::BuiltinLintDiagnostics::
4917 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4921 for ambiguity_error in &self.ambiguity_errors {
4922 self.report_ambiguity_error(ambiguity_error);
4925 let mut reported_spans = FxHashSet::default();
4926 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4927 if reported_spans.insert(dedup_span) {
4928 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4929 binding.descr(), ident.name);
4934 fn report_with_use_injections(&mut self, krate: &Crate) {
4935 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4936 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4937 if !candidates.is_empty() {
4938 show_candidates(&mut err, span, &candidates, better, found_use);
4944 fn report_conflict<'b>(&mut self,
4948 new_binding: &NameBinding<'b>,
4949 old_binding: &NameBinding<'b>) {
4950 // Error on the second of two conflicting names
4951 if old_binding.span.lo() > new_binding.span.lo() {
4952 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4955 let container = match parent.kind {
4956 ModuleKind::Def(Def::Mod(_), _) => "module",
4957 ModuleKind::Def(Def::Trait(_), _) => "trait",
4958 ModuleKind::Block(..) => "block",
4962 let old_noun = match old_binding.is_import() {
4964 false => "definition",
4967 let new_participle = match new_binding.is_import() {
4972 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4974 if let Some(s) = self.name_already_seen.get(&name) {
4980 let old_kind = match (ns, old_binding.module()) {
4981 (ValueNS, _) => "value",
4982 (MacroNS, _) => "macro",
4983 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4984 (TypeNS, Some(module)) if module.is_normal() => "module",
4985 (TypeNS, Some(module)) if module.is_trait() => "trait",
4986 (TypeNS, _) => "type",
4989 let msg = format!("the name `{}` is defined multiple times", name);
4991 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4992 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4993 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4994 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4995 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4997 _ => match (old_binding.is_import(), new_binding.is_import()) {
4998 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4999 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5000 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5004 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5009 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5010 if !old_binding.span.is_dummy() {
5011 err.span_label(self.session.source_map().def_span(old_binding.span),
5012 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
5015 // See https://github.com/rust-lang/rust/issues/32354
5016 if old_binding.is_import() || new_binding.is_import() {
5017 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
5023 let cm = self.session.source_map();
5024 let rename_msg = "you can use `as` to change the binding name of the import";
5028 NameBindingKind::Import { directive, ..},
5031 cm.span_to_snippet(binding.span),
5032 binding.kind.clone(),
5033 binding.span.is_dummy(),
5035 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5036 format!("Other{}", name)
5038 format!("other_{}", name)
5041 err.span_suggestion_with_applicability(
5044 match directive.subclass {
5045 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5046 format!("self as {}", suggested_name),
5047 ImportDirectiveSubclass::SingleImport { source, .. } =>
5050 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
5052 if snippet.ends_with(";") {
5058 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5060 "extern crate {} as {};",
5061 source.unwrap_or(target.name),
5064 _ => unreachable!(),
5066 Applicability::MaybeIncorrect,
5069 err.span_label(binding.span, rename_msg);
5074 self.name_already_seen.insert(name, span);
5077 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5078 -> Option<&'a NameBinding<'a>> {
5079 if ident.is_path_segment_keyword() {
5080 // Make sure `self`, `super` etc produce an error when passed to here.
5083 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5084 if let Some(binding) = entry.extern_crate_item {
5087 let crate_id = if !speculative {
5088 self.crate_loader.process_path_extern(ident.name, ident.span)
5089 } else if let Some(crate_id) =
5090 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5095 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5096 self.populate_module_if_necessary(&crate_root);
5097 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5098 .to_name_binding(self.arenas))
5104 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5105 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5108 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5109 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5112 fn names_to_string(idents: &[Ident]) -> String {
5113 let mut result = String::new();
5114 for (i, ident) in idents.iter()
5115 .filter(|ident| ident.name != keywords::PathRoot.name())
5118 result.push_str("::");
5120 result.push_str(&ident.as_str());
5125 fn path_names_to_string(path: &Path) -> String {
5126 names_to_string(&path.segments.iter()
5127 .map(|seg| seg.ident)
5128 .collect::<Vec<_>>())
5131 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
5132 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
5133 let variant_path = &suggestion.path;
5134 let variant_path_string = path_names_to_string(variant_path);
5136 let path_len = suggestion.path.segments.len();
5137 let enum_path = ast::Path {
5138 span: suggestion.path.span,
5139 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5141 let enum_path_string = path_names_to_string(&enum_path);
5143 (suggestion.path.span, variant_path_string, enum_path_string)
5147 /// When an entity with a given name is not available in scope, we search for
5148 /// entities with that name in all crates. This method allows outputting the
5149 /// results of this search in a programmer-friendly way
5150 fn show_candidates(err: &mut DiagnosticBuilder,
5151 // This is `None` if all placement locations are inside expansions
5153 candidates: &[ImportSuggestion],
5157 // we want consistent results across executions, but candidates are produced
5158 // by iterating through a hash map, so make sure they are ordered:
5159 let mut path_strings: Vec<_> =
5160 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5161 path_strings.sort();
5163 let better = if better { "better " } else { "" };
5164 let msg_diff = match path_strings.len() {
5165 1 => " is found in another module, you can import it",
5166 _ => "s are found in other modules, you can import them",
5168 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5170 if let Some(span) = span {
5171 for candidate in &mut path_strings {
5172 // produce an additional newline to separate the new use statement
5173 // from the directly following item.
5174 let additional_newline = if found_use {
5179 *candidate = format!("use {};\n{}", candidate, additional_newline);
5182 err.span_suggestions_with_applicability(
5185 path_strings.into_iter(),
5186 Applicability::Unspecified,
5191 for candidate in path_strings {
5193 msg.push_str(&candidate);
5198 /// A somewhat inefficient routine to obtain the name of a module.
5199 fn module_to_string(module: Module) -> Option<String> {
5200 let mut names = Vec::new();
5202 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5203 if let ModuleKind::Def(_, name) = module.kind {
5204 if let Some(parent) = module.parent {
5205 names.push(Ident::with_empty_ctxt(name));
5206 collect_mod(names, parent);
5209 // danger, shouldn't be ident?
5210 names.push(Ident::from_str("<opaque>"));
5211 collect_mod(names, module.parent.unwrap());
5214 collect_mod(&mut names, module);
5216 if names.is_empty() {
5219 Some(names_to_string(&names.into_iter()
5221 .collect::<Vec<_>>()))
5224 fn err_path_resolution() -> PathResolution {
5225 PathResolution::new(Def::Err)
5228 #[derive(PartialEq,Copy, Clone)]
5229 pub enum MakeGlobMap {
5234 #[derive(Copy, Clone, Debug)]
5236 /// Do not issue the lint
5239 /// This lint applies to some random path like `impl ::foo::Bar`
5240 /// or whatever. In this case, we can take the span of that path.
5243 /// This lint comes from a `use` statement. In this case, what we
5244 /// care about really is the *root* `use` statement; e.g., if we
5245 /// have nested things like `use a::{b, c}`, we care about the
5247 UsePath { root_id: NodeId, root_span: Span },
5249 /// This is the "trait item" from a fully qualified path. For example,
5250 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5251 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5252 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5256 fn node_id(&self) -> Option<NodeId> {
5258 CrateLint::No => None,
5259 CrateLint::SimplePath(id) |
5260 CrateLint::UsePath { root_id: id, .. } |
5261 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5266 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }