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, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
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 is_local(&self) -> bool {
1177 self.normal_ancestor_id.is_local()
1180 fn nearest_item_scope(&'a self) -> Module<'a> {
1181 if self.is_trait() { self.parent.unwrap() } else { self }
1184 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1185 while !ptr::eq(self, other) {
1186 if let Some(parent) = other.parent {
1196 impl<'a> fmt::Debug for ModuleData<'a> {
1197 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1198 write!(f, "{:?}", self.def())
1202 /// Records a possibly-private value, type, or module definition.
1203 #[derive(Clone, Debug)]
1204 pub struct NameBinding<'a> {
1205 kind: NameBindingKind<'a>,
1208 vis: ty::Visibility,
1211 pub trait ToNameBinding<'a> {
1212 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1215 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1216 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1221 #[derive(Clone, Debug)]
1222 enum NameBindingKind<'a> {
1223 Def(Def, /* is_macro_export */ bool),
1226 binding: &'a NameBinding<'a>,
1227 directive: &'a ImportDirective<'a>,
1231 kind: AmbiguityKind,
1232 b1: &'a NameBinding<'a>,
1233 b2: &'a NameBinding<'a>,
1237 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1239 struct UseError<'a> {
1240 err: DiagnosticBuilder<'a>,
1241 /// Attach `use` statements for these candidates
1242 candidates: Vec<ImportSuggestion>,
1243 /// The node id of the module to place the use statements in
1245 /// Whether the diagnostic should state that it's "better"
1249 #[derive(Clone, Copy, PartialEq, Debug)]
1250 enum AmbiguityKind {
1255 LegacyHelperVsPrelude,
1260 MoreExpandedVsOuter,
1263 impl AmbiguityKind {
1264 fn descr(self) -> &'static str {
1266 AmbiguityKind::Import =>
1267 "name vs any other name during import resolution",
1268 AmbiguityKind::AbsolutePath =>
1269 "name in the crate root vs extern crate during absolute path resolution",
1270 AmbiguityKind::BuiltinAttr =>
1271 "built-in attribute vs any other name",
1272 AmbiguityKind::DeriveHelper =>
1273 "derive helper attribute vs any other name",
1274 AmbiguityKind::LegacyHelperVsPrelude =>
1275 "legacy plugin helper attribute vs name from prelude",
1276 AmbiguityKind::LegacyVsModern =>
1277 "`macro_rules` vs non-`macro_rules` from other module",
1278 AmbiguityKind::GlobVsOuter =>
1279 "glob import vs any other name from outer scope during import/macro resolution",
1280 AmbiguityKind::GlobVsGlob =>
1281 "glob import vs glob import in the same module",
1282 AmbiguityKind::GlobVsExpanded =>
1283 "glob import vs macro-expanded name in the same \
1284 module during import/macro resolution",
1285 AmbiguityKind::MoreExpandedVsOuter =>
1286 "macro-expanded name vs less macro-expanded name \
1287 from outer scope during import/macro resolution",
1292 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1293 #[derive(Clone, Copy, PartialEq)]
1294 enum AmbiguityErrorMisc {
1301 struct AmbiguityError<'a> {
1302 kind: AmbiguityKind,
1304 b1: &'a NameBinding<'a>,
1305 b2: &'a NameBinding<'a>,
1306 misc1: AmbiguityErrorMisc,
1307 misc2: AmbiguityErrorMisc,
1310 impl<'a> NameBinding<'a> {
1311 fn module(&self) -> Option<Module<'a>> {
1313 NameBindingKind::Module(module) => Some(module),
1314 NameBindingKind::Import { binding, .. } => binding.module(),
1319 fn def(&self) -> Def {
1321 NameBindingKind::Def(def, _) => def,
1322 NameBindingKind::Module(module) => module.def().unwrap(),
1323 NameBindingKind::Import { binding, .. } => binding.def(),
1324 NameBindingKind::Ambiguity { .. } => Def::Err,
1328 fn def_ignoring_ambiguity(&self) -> Def {
1330 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1331 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1336 // We sometimes need to treat variants as `pub` for backwards compatibility
1337 fn pseudo_vis(&self) -> ty::Visibility {
1338 if self.is_variant() && self.def().def_id().is_local() {
1339 ty::Visibility::Public
1345 fn is_variant(&self) -> bool {
1347 NameBindingKind::Def(Def::Variant(..), _) |
1348 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1353 fn is_extern_crate(&self) -> bool {
1355 NameBindingKind::Import {
1356 directive: &ImportDirective {
1357 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1360 NameBindingKind::Module(
1361 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1362 ) => def_id.index == CRATE_DEF_INDEX,
1367 fn is_import(&self) -> bool {
1369 NameBindingKind::Import { .. } => true,
1374 fn is_glob_import(&self) -> bool {
1376 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1377 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1382 fn is_importable(&self) -> bool {
1384 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1389 fn is_macro_def(&self) -> bool {
1391 NameBindingKind::Def(Def::Macro(..), _) => true,
1396 fn macro_kind(&self) -> Option<MacroKind> {
1397 match self.def_ignoring_ambiguity() {
1398 Def::Macro(_, kind) => Some(kind),
1399 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1404 fn descr(&self) -> &'static str {
1405 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1408 fn article(&self) -> &'static str {
1409 if self.is_extern_crate() { "an" } else { self.def().article() }
1412 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1413 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1414 // Then this function returns `true` if `self` may emerge from a macro *after* that
1415 // in some later round and screw up our previously found resolution.
1416 // See more detailed explanation in
1417 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1418 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1419 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1420 // Expansions are partially ordered, so "may appear after" is an inversion of
1421 // "certainly appears before or simultaneously" and includes unordered cases.
1422 let self_parent_expansion = self.expansion;
1423 let other_parent_expansion = binding.expansion;
1424 let certainly_before_other_or_simultaneously =
1425 other_parent_expansion.is_descendant_of(self_parent_expansion);
1426 let certainly_before_invoc_or_simultaneously =
1427 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1428 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1432 /// Interns the names of the primitive types.
1434 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1435 /// special handling, since they have no place of origin.
1437 struct PrimitiveTypeTable {
1438 primitive_types: FxHashMap<Name, PrimTy>,
1441 impl PrimitiveTypeTable {
1442 fn new() -> PrimitiveTypeTable {
1443 let mut table = PrimitiveTypeTable::default();
1445 table.intern("bool", Bool);
1446 table.intern("char", Char);
1447 table.intern("f32", Float(FloatTy::F32));
1448 table.intern("f64", Float(FloatTy::F64));
1449 table.intern("isize", Int(IntTy::Isize));
1450 table.intern("i8", Int(IntTy::I8));
1451 table.intern("i16", Int(IntTy::I16));
1452 table.intern("i32", Int(IntTy::I32));
1453 table.intern("i64", Int(IntTy::I64));
1454 table.intern("i128", Int(IntTy::I128));
1455 table.intern("str", Str);
1456 table.intern("usize", Uint(UintTy::Usize));
1457 table.intern("u8", Uint(UintTy::U8));
1458 table.intern("u16", Uint(UintTy::U16));
1459 table.intern("u32", Uint(UintTy::U32));
1460 table.intern("u64", Uint(UintTy::U64));
1461 table.intern("u128", Uint(UintTy::U128));
1465 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1466 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1470 #[derive(Default, Clone)]
1471 pub struct ExternPreludeEntry<'a> {
1472 extern_crate_item: Option<&'a NameBinding<'a>>,
1473 pub introduced_by_item: bool,
1476 /// The main resolver class.
1478 /// This is the visitor that walks the whole crate.
1479 pub struct Resolver<'a, 'b: 'a> {
1480 session: &'a Session,
1483 pub definitions: Definitions,
1485 graph_root: Module<'a>,
1487 prelude: Option<Module<'a>>,
1488 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1490 /// n.b. This is used only for better diagnostics, not name resolution itself.
1491 has_self: FxHashSet<DefId>,
1493 /// Names of fields of an item `DefId` accessible with dot syntax.
1494 /// Used for hints during error reporting.
1495 field_names: FxHashMap<DefId, Vec<Name>>,
1497 /// All imports known to succeed or fail.
1498 determined_imports: Vec<&'a ImportDirective<'a>>,
1500 /// All non-determined imports.
1501 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1503 /// The module that represents the current item scope.
1504 current_module: Module<'a>,
1506 /// The current set of local scopes for types and values.
1507 /// FIXME #4948: Reuse ribs to avoid allocation.
1508 ribs: PerNS<Vec<Rib<'a>>>,
1510 /// The current set of local scopes, for labels.
1511 label_ribs: Vec<Rib<'a>>,
1513 /// The trait that the current context can refer to.
1514 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1516 /// The current self type if inside an impl (used for better errors).
1517 current_self_type: Option<Ty>,
1519 /// The current self item if inside an ADT (used for better errors).
1520 current_self_item: Option<NodeId>,
1522 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1523 /// We are resolving a last import segment during import validation.
1524 last_import_segment: bool,
1525 /// This binding should be ignored during in-module resolution, so that we don't get
1526 /// "self-confirming" import resolutions during import validation.
1527 blacklisted_binding: Option<&'a NameBinding<'a>>,
1529 /// The idents for the primitive types.
1530 primitive_type_table: PrimitiveTypeTable,
1533 import_map: ImportMap,
1534 pub freevars: FreevarMap,
1535 freevars_seen: NodeMap<NodeMap<usize>>,
1536 pub export_map: ExportMap,
1537 pub trait_map: TraitMap,
1539 /// A map from nodes to anonymous modules.
1540 /// Anonymous modules are pseudo-modules that are implicitly created around items
1541 /// contained within blocks.
1543 /// For example, if we have this:
1551 /// There will be an anonymous module created around `g` with the ID of the
1552 /// entry block for `f`.
1553 block_map: NodeMap<Module<'a>>,
1554 module_map: FxHashMap<DefId, Module<'a>>,
1555 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1556 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1558 pub make_glob_map: bool,
1559 /// Maps imports to the names of items actually imported (this actually maps
1560 /// all imports, but only glob imports are actually interesting).
1561 pub glob_map: GlobMap,
1563 used_imports: FxHashSet<(NodeId, Namespace)>,
1564 pub maybe_unused_trait_imports: NodeSet,
1565 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1567 /// A list of labels as of yet unused. Labels will be removed from this map when
1568 /// they are used (in a `break` or `continue` statement)
1569 pub unused_labels: FxHashMap<NodeId, Span>,
1571 /// privacy errors are delayed until the end in order to deduplicate them
1572 privacy_errors: Vec<PrivacyError<'a>>,
1573 /// ambiguity errors are delayed for deduplication
1574 ambiguity_errors: Vec<AmbiguityError<'a>>,
1575 /// `use` injections are delayed for better placement and deduplication
1576 use_injections: Vec<UseError<'a>>,
1577 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1578 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1580 arenas: &'a ResolverArenas<'a>,
1581 dummy_binding: &'a NameBinding<'a>,
1583 crate_loader: &'a mut CrateLoader<'b>,
1584 macro_names: FxHashSet<Ident>,
1585 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1586 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1587 pub all_macros: FxHashMap<Name, Def>,
1588 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1589 macro_defs: FxHashMap<Mark, DefId>,
1590 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1591 pub found_unresolved_macro: bool,
1593 /// List of crate local macros that we need to warn about as being unused.
1594 /// Right now this only includes macro_rules! macros, and macros 2.0.
1595 unused_macros: FxHashSet<DefId>,
1597 /// Maps the `Mark` of an expansion to its containing module or block.
1598 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1600 /// Avoid duplicated errors for "name already defined".
1601 name_already_seen: FxHashMap<Name, Span>,
1603 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1605 /// This table maps struct IDs into struct constructor IDs,
1606 /// it's not used during normal resolution, only for better error reporting.
1607 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1609 /// Only used for better errors on `fn(): fn()`
1610 current_type_ascription: Vec<Span>,
1612 injected_crate: Option<Module<'a>>,
1615 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1617 pub struct ResolverArenas<'a> {
1618 modules: arena::TypedArena<ModuleData<'a>>,
1619 local_modules: RefCell<Vec<Module<'a>>>,
1620 name_bindings: arena::TypedArena<NameBinding<'a>>,
1621 import_directives: arena::TypedArena<ImportDirective<'a>>,
1622 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1623 invocation_data: arena::TypedArena<InvocationData<'a>>,
1624 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1627 impl<'a> ResolverArenas<'a> {
1628 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1629 let module = self.modules.alloc(module);
1630 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1631 self.local_modules.borrow_mut().push(module);
1635 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1636 self.local_modules.borrow()
1638 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1639 self.name_bindings.alloc(name_binding)
1641 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1642 -> &'a ImportDirective {
1643 self.import_directives.alloc(import_directive)
1645 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1646 self.name_resolutions.alloc(Default::default())
1648 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1649 -> &'a InvocationData<'a> {
1650 self.invocation_data.alloc(expansion_data)
1652 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1653 self.legacy_bindings.alloc(binding)
1657 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1658 fn parent(self, id: DefId) -> Option<DefId> {
1660 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1661 _ => self.cstore.def_key(id).parent,
1662 }.map(|index| DefId { index, ..id })
1666 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1667 /// the resolver is no longer needed as all the relevant information is inline.
1668 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1669 fn resolve_hir_path(
1674 self.resolve_hir_path_cb(path, is_value,
1675 |resolver, span, error| resolve_error(resolver, span, error))
1678 fn resolve_str_path(
1681 crate_root: Option<&str>,
1682 components: &[&str],
1685 let segments = iter::once(keywords::PathRoot.ident())
1687 crate_root.into_iter()
1688 .chain(components.iter().cloned())
1689 .map(Ident::from_str)
1690 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1693 let path = ast::Path {
1698 self.resolve_hir_path(&path, is_value)
1701 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1702 self.def_map.get(&id).cloned()
1705 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1706 self.import_map.get(&id).cloned().unwrap_or_default()
1709 fn definitions(&mut self) -> &mut Definitions {
1710 &mut self.definitions
1714 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1715 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1716 /// isn't something that can be returned because it can't be made to live that long,
1717 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1718 /// just that an error occurred.
1719 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1720 -> Result<hir::Path, ()> {
1722 let mut errored = false;
1724 let path = if path_str.starts_with("::") {
1727 segments: iter::once(keywords::PathRoot.ident())
1729 path_str.split("::").skip(1).map(Ident::from_str)
1731 .map(|i| self.new_ast_path_segment(i))
1739 .map(Ident::from_str)
1740 .map(|i| self.new_ast_path_segment(i))
1744 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1745 if errored || path.def == Def::Err {
1752 /// resolve_hir_path, but takes a callback in case there was an error
1753 fn resolve_hir_path_cb<F>(
1759 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1761 let namespace = if is_value { ValueNS } else { TypeNS };
1762 let span = path.span;
1763 let segments = &path.segments;
1764 let path = Segment::from_path(&path);
1765 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1766 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1767 span, CrateLint::No) {
1768 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1769 module.def().unwrap(),
1770 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1771 path_res.base_def(),
1772 PathResult::NonModule(..) => {
1773 let msg = "type-relative paths are not supported in this context";
1774 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1777 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1778 PathResult::Failed(span, msg, _) => {
1779 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1784 let segments: Vec<_> = segments.iter().map(|seg| {
1785 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1786 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1792 segments: segments.into(),
1796 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1797 let mut seg = ast::PathSegment::from_ident(ident);
1798 seg.id = self.session.next_node_id();
1803 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1804 pub fn new(session: &'a Session,
1808 make_glob_map: MakeGlobMap,
1809 crate_loader: &'a mut CrateLoader<'crateloader>,
1810 arenas: &'a ResolverArenas<'a>)
1811 -> Resolver<'a, 'crateloader> {
1812 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1813 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1814 let graph_root = arenas.alloc_module(ModuleData {
1815 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1816 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1818 let mut module_map = FxHashMap::default();
1819 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1821 let mut definitions = Definitions::new();
1822 DefCollector::new(&mut definitions, Mark::root())
1823 .collect_root(crate_name, session.local_crate_disambiguator());
1825 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
1826 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1829 if !attr::contains_name(&krate.attrs, "no_core") {
1830 extern_prelude.insert(Ident::from_str("core"), Default::default());
1831 if !attr::contains_name(&krate.attrs, "no_std") {
1832 extern_prelude.insert(Ident::from_str("std"), Default::default());
1833 if session.rust_2018() {
1834 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1839 let mut invocations = FxHashMap::default();
1840 invocations.insert(Mark::root(),
1841 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1843 let mut macro_defs = FxHashMap::default();
1844 macro_defs.insert(Mark::root(), root_def_id);
1853 // The outermost module has def ID 0; this is not reflected in the
1859 has_self: FxHashSet::default(),
1860 field_names: FxHashMap::default(),
1862 determined_imports: Vec::new(),
1863 indeterminate_imports: Vec::new(),
1865 current_module: graph_root,
1867 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1868 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1869 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1871 label_ribs: Vec::new(),
1873 current_trait_ref: None,
1874 current_self_type: None,
1875 current_self_item: None,
1876 last_import_segment: false,
1877 blacklisted_binding: None,
1879 primitive_type_table: PrimitiveTypeTable::new(),
1881 def_map: Default::default(),
1882 import_map: Default::default(),
1883 freevars: Default::default(),
1884 freevars_seen: Default::default(),
1885 export_map: FxHashMap::default(),
1886 trait_map: Default::default(),
1888 block_map: Default::default(),
1889 extern_module_map: FxHashMap::default(),
1890 binding_parent_modules: FxHashMap::default(),
1892 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1893 glob_map: Default::default(),
1895 used_imports: FxHashSet::default(),
1896 maybe_unused_trait_imports: Default::default(),
1897 maybe_unused_extern_crates: Vec::new(),
1899 unused_labels: FxHashMap::default(),
1901 privacy_errors: Vec::new(),
1902 ambiguity_errors: Vec::new(),
1903 use_injections: Vec::new(),
1904 macro_expanded_macro_export_errors: BTreeSet::new(),
1907 dummy_binding: arenas.alloc_name_binding(NameBinding {
1908 kind: NameBindingKind::Def(Def::Err, false),
1909 expansion: Mark::root(),
1911 vis: ty::Visibility::Public,
1915 macro_names: FxHashSet::default(),
1916 builtin_macros: FxHashMap::default(),
1917 macro_use_prelude: FxHashMap::default(),
1918 all_macros: FxHashMap::default(),
1919 macro_map: FxHashMap::default(),
1922 local_macro_def_scopes: FxHashMap::default(),
1923 name_already_seen: FxHashMap::default(),
1924 potentially_unused_imports: Vec::new(),
1925 struct_constructors: Default::default(),
1926 found_unresolved_macro: false,
1927 unused_macros: FxHashSet::default(),
1928 current_type_ascription: Vec::new(),
1929 injected_crate: None,
1933 pub fn arenas() -> ResolverArenas<'a> {
1937 /// Runs the function on each namespace.
1938 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1944 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1946 match self.macro_defs.get(&ctxt.outer()) {
1947 Some(&def_id) => return def_id,
1948 None => ctxt.remove_mark(),
1953 /// Entry point to crate resolution.
1954 pub fn resolve_crate(&mut self, krate: &Crate) {
1955 ImportResolver { resolver: self }.finalize_imports();
1956 self.current_module = self.graph_root;
1957 self.finalize_current_module_macro_resolutions();
1959 visit::walk_crate(self, krate);
1961 check_unused::check_crate(self, krate);
1962 self.report_errors(krate);
1963 self.crate_loader.postprocess(krate);
1970 normal_ancestor_id: DefId,
1974 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1975 self.arenas.alloc_module(module)
1978 fn record_use(&mut self, ident: Ident, ns: Namespace,
1979 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1980 match used_binding.kind {
1981 NameBindingKind::Import { directive, binding, ref used } if !used.get() => {
1982 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1983 // but not introduce it, as used if they are accessed from lexical scope.
1984 if is_lexical_scope {
1985 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1986 if let Some(crate_item) = entry.extern_crate_item {
1987 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1994 directive.used.set(true);
1995 self.used_imports.insert((directive.id, ns));
1996 self.add_to_glob_map(directive.id, ident);
1997 self.record_use(ident, ns, binding, false);
1999 NameBindingKind::Ambiguity { kind, b1, b2 } => {
2000 self.ambiguity_errors.push(AmbiguityError {
2001 kind, ident, b1, b2,
2002 misc1: AmbiguityErrorMisc::None,
2003 misc2: AmbiguityErrorMisc::None,
2010 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
2011 if self.make_glob_map {
2012 self.glob_map.entry(id).or_default().insert(ident.name);
2016 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2017 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2018 /// `ident` in the first scope that defines it (or None if no scopes define it).
2020 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2021 /// the items are defined in the block. For example,
2024 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2027 /// g(); // This resolves to the local variable `g` since it shadows the item.
2031 /// Invariant: This must only be called during main resolution, not during
2032 /// import resolution.
2033 fn resolve_ident_in_lexical_scope(&mut self,
2036 record_used_id: Option<NodeId>,
2038 -> Option<LexicalScopeBinding<'a>> {
2039 let record_used = record_used_id.is_some();
2040 assert!(ns == TypeNS || ns == ValueNS);
2042 ident.span = if ident.name == keywords::SelfUpper.name() {
2043 // FIXME(jseyfried) improve `Self` hygiene
2044 ident.span.with_ctxt(SyntaxContext::empty())
2049 ident = ident.modern_and_legacy();
2052 // Walk backwards up the ribs in scope.
2053 let mut module = self.graph_root;
2054 for i in (0 .. self.ribs[ns].len()).rev() {
2055 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2056 // The ident resolves to a type parameter or local variable.
2057 return Some(LexicalScopeBinding::Def(
2058 self.adjust_local_def(ns, i, def, record_used, path_span)
2062 module = match self.ribs[ns][i].kind {
2063 ModuleRibKind(module) => module,
2064 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2065 // If an invocation of this macro created `ident`, give up on `ident`
2066 // and switch to `ident`'s source from the macro definition.
2067 ident.span.remove_mark();
2073 let item = self.resolve_ident_in_module_unadjusted(
2074 ModuleOrUniformRoot::Module(module),
2080 if let Ok(binding) = item {
2081 // The ident resolves to an item.
2082 return Some(LexicalScopeBinding::Item(binding));
2086 ModuleKind::Block(..) => {}, // We can see through blocks
2091 ident.span = ident.span.modern();
2092 let mut poisoned = None;
2094 let opt_module = if let Some(node_id) = record_used_id {
2095 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2096 node_id, &mut poisoned)
2098 self.hygienic_lexical_parent(module, &mut ident.span)
2100 module = unwrap_or!(opt_module, break);
2101 let orig_current_module = self.current_module;
2102 self.current_module = module; // Lexical resolutions can never be a privacy error.
2103 let result = self.resolve_ident_in_module_unadjusted(
2104 ModuleOrUniformRoot::Module(module),
2110 self.current_module = orig_current_module;
2114 if let Some(node_id) = poisoned {
2115 self.session.buffer_lint_with_diagnostic(
2116 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2117 node_id, ident.span,
2118 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2119 lint::builtin::BuiltinLintDiagnostics::
2120 ProcMacroDeriveResolutionFallback(ident.span),
2123 return Some(LexicalScopeBinding::Item(binding))
2125 Err(Determined) => continue,
2126 Err(Undetermined) =>
2127 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2131 if !module.no_implicit_prelude {
2133 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2134 return Some(LexicalScopeBinding::Item(binding));
2137 if ns == TypeNS && is_known_tool(ident.name) {
2138 let binding = (Def::ToolMod, ty::Visibility::Public,
2139 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2140 return Some(LexicalScopeBinding::Item(binding));
2142 if let Some(prelude) = self.prelude {
2143 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2144 ModuleOrUniformRoot::Module(prelude),
2150 return Some(LexicalScopeBinding::Item(binding));
2158 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2159 -> Option<Module<'a>> {
2160 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2161 return Some(self.macro_def_scope(span.remove_mark()));
2164 if let ModuleKind::Block(..) = module.kind {
2165 return Some(module.parent.unwrap());
2171 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2172 span: &mut Span, node_id: NodeId,
2173 poisoned: &mut Option<NodeId>)
2174 -> Option<Module<'a>> {
2175 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2179 // We need to support the next case under a deprecation warning
2182 // ---- begin: this comes from a proc macro derive
2183 // mod implementation_details {
2184 // // Note that `MyStruct` is not in scope here.
2185 // impl SomeTrait for MyStruct { ... }
2189 // So we have to fall back to the module's parent during lexical resolution in this case.
2190 if let Some(parent) = module.parent {
2191 // Inner module is inside the macro, parent module is outside of the macro.
2192 if module.expansion != parent.expansion &&
2193 module.expansion.is_descendant_of(parent.expansion) {
2194 // The macro is a proc macro derive
2195 if module.expansion.looks_like_proc_macro_derive() {
2196 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2197 *poisoned = Some(node_id);
2198 return module.parent;
2207 fn resolve_ident_in_module(
2209 module: ModuleOrUniformRoot<'a>,
2212 parent_scope: Option<&ParentScope<'a>>,
2215 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2216 self.resolve_ident_in_module_ext(
2217 module, ident, ns, parent_scope, record_used, path_span
2218 ).map_err(|(determinacy, _)| determinacy)
2221 fn resolve_ident_in_module_ext(
2223 module: ModuleOrUniformRoot<'a>,
2226 parent_scope: Option<&ParentScope<'a>>,
2229 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2230 let orig_current_module = self.current_module;
2232 ModuleOrUniformRoot::Module(module) => {
2233 ident.span = ident.span.modern();
2234 if let Some(def) = ident.span.adjust(module.expansion) {
2235 self.current_module = self.macro_def_scope(def);
2238 ModuleOrUniformRoot::ExternPrelude => {
2239 ident.span = ident.span.modern();
2240 ident.span.adjust(Mark::root());
2242 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2243 ModuleOrUniformRoot::CurrentScope => {
2247 let result = self.resolve_ident_in_module_unadjusted_ext(
2248 module, ident, ns, parent_scope, false, record_used, path_span,
2250 self.current_module = orig_current_module;
2254 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2255 let mut ctxt = ident.span.ctxt();
2256 let mark = if ident.name == keywords::DollarCrate.name() {
2257 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2258 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2259 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2260 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2261 // definitions actually produced by `macro` and `macro` definitions produced by
2262 // `macro_rules!`, but at least such configurations are not stable yet.
2263 ctxt = ctxt.modern_and_legacy();
2264 let mut iter = ctxt.marks().into_iter().rev().peekable();
2265 let mut result = None;
2266 // Find the last modern mark from the end if it exists.
2267 while let Some(&(mark, transparency)) = iter.peek() {
2268 if transparency == Transparency::Opaque {
2269 result = Some(mark);
2275 // Then find the last legacy mark from the end if it exists.
2276 for (mark, transparency) in iter {
2277 if transparency == Transparency::SemiTransparent {
2278 result = Some(mark);
2285 ctxt = ctxt.modern();
2286 ctxt.adjust(Mark::root())
2288 let module = match mark {
2289 Some(def) => self.macro_def_scope(def),
2290 None => return self.graph_root,
2292 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2295 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2296 let mut module = self.get_module(module.normal_ancestor_id);
2297 while module.span.ctxt().modern() != *ctxt {
2298 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2299 module = self.get_module(parent.normal_ancestor_id);
2306 // We maintain a list of value ribs and type ribs.
2308 // Simultaneously, we keep track of the current position in the module
2309 // graph in the `current_module` pointer. When we go to resolve a name in
2310 // the value or type namespaces, we first look through all the ribs and
2311 // then query the module graph. When we resolve a name in the module
2312 // namespace, we can skip all the ribs (since nested modules are not
2313 // allowed within blocks in Rust) and jump straight to the current module
2316 // Named implementations are handled separately. When we find a method
2317 // call, we consult the module node to find all of the implementations in
2318 // scope. This information is lazily cached in the module node. We then
2319 // generate a fake "implementation scope" containing all the
2320 // implementations thus found, for compatibility with old resolve pass.
2322 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2323 where F: FnOnce(&mut Resolver) -> T
2325 let id = self.definitions.local_def_id(id);
2326 let module = self.module_map.get(&id).cloned(); // clones a reference
2327 if let Some(module) = module {
2328 // Move down in the graph.
2329 let orig_module = replace(&mut self.current_module, module);
2330 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2331 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2333 self.finalize_current_module_macro_resolutions();
2336 self.current_module = orig_module;
2337 self.ribs[ValueNS].pop();
2338 self.ribs[TypeNS].pop();
2345 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2346 /// is returned by the given predicate function
2348 /// Stops after meeting a closure.
2349 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2350 where P: Fn(&Rib, Ident) -> Option<R>
2352 for rib in self.label_ribs.iter().rev() {
2355 // If an invocation of this macro created `ident`, give up on `ident`
2356 // and switch to `ident`'s source from the macro definition.
2357 MacroDefinition(def) => {
2358 if def == self.macro_def(ident.span.ctxt()) {
2359 ident.span.remove_mark();
2363 // Do not resolve labels across function boundary
2367 let r = pred(rib, ident);
2375 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2376 self.with_current_self_item(item, |this| {
2377 this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2378 let item_def_id = this.definitions.local_def_id(item.id);
2379 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2380 visit::walk_item(this, item);
2386 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2387 let segments = &use_tree.prefix.segments;
2388 if !segments.is_empty() {
2389 let ident = segments[0].ident;
2390 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2394 let nss = match use_tree.kind {
2395 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2399 if let Some(LexicalScopeBinding::Def(..)) =
2400 self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2401 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2402 self.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2405 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2406 for (use_tree, _) in use_trees {
2407 self.future_proof_import(use_tree);
2412 fn resolve_item(&mut self, item: &Item) {
2413 let name = item.ident.name;
2414 debug!("(resolving item) resolving {}", name);
2417 ItemKind::Ty(_, ref generics) |
2418 ItemKind::Fn(_, _, ref generics, _) |
2419 ItemKind::Existential(_, ref generics) => {
2420 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2421 |this| visit::walk_item(this, item));
2424 ItemKind::Enum(_, ref generics) |
2425 ItemKind::Struct(_, ref generics) |
2426 ItemKind::Union(_, ref generics) => {
2427 self.resolve_adt(item, generics);
2430 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2431 self.resolve_implementation(generics,
2437 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2438 // Create a new rib for the trait-wide type parameters.
2439 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2440 let local_def_id = this.definitions.local_def_id(item.id);
2441 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2442 this.visit_generics(generics);
2443 walk_list!(this, visit_param_bound, bounds);
2445 for trait_item in trait_items {
2446 let type_parameters = HasTypeParameters(&trait_item.generics,
2447 TraitOrImplItemRibKind);
2448 this.with_type_parameter_rib(type_parameters, |this| {
2449 match trait_item.node {
2450 TraitItemKind::Const(ref ty, ref default) => {
2453 // Only impose the restrictions of
2454 // ConstRibKind for an actual constant
2455 // expression in a provided default.
2456 if let Some(ref expr) = *default{
2457 this.with_constant_rib(|this| {
2458 this.visit_expr(expr);
2462 TraitItemKind::Method(_, _) => {
2463 visit::walk_trait_item(this, trait_item)
2465 TraitItemKind::Type(..) => {
2466 visit::walk_trait_item(this, trait_item)
2468 TraitItemKind::Macro(_) => {
2469 panic!("unexpanded macro in resolve!")
2478 ItemKind::TraitAlias(ref generics, ref bounds) => {
2479 // Create a new rib for the trait-wide type parameters.
2480 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2481 let local_def_id = this.definitions.local_def_id(item.id);
2482 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2483 this.visit_generics(generics);
2484 walk_list!(this, visit_param_bound, bounds);
2489 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2490 self.with_scope(item.id, |this| {
2491 visit::walk_item(this, item);
2495 ItemKind::Static(ref ty, _, ref expr) |
2496 ItemKind::Const(ref ty, ref expr) => {
2497 self.with_item_rib(|this| {
2499 this.with_constant_rib(|this| {
2500 this.visit_expr(expr);
2505 ItemKind::Use(ref use_tree) => {
2506 self.future_proof_import(use_tree);
2509 ItemKind::ExternCrate(..) |
2510 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2511 // do nothing, these are just around to be encoded
2514 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2518 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2519 where F: FnOnce(&mut Resolver)
2521 match type_parameters {
2522 HasTypeParameters(generics, rib_kind) => {
2523 let mut function_type_rib = Rib::new(rib_kind);
2524 let mut seen_bindings = FxHashMap::default();
2525 for param in &generics.params {
2527 GenericParamKind::Lifetime { .. } => {}
2528 GenericParamKind::Type { .. } => {
2529 let ident = param.ident.modern();
2530 debug!("with_type_parameter_rib: {}", param.id);
2532 if seen_bindings.contains_key(&ident) {
2533 let span = seen_bindings.get(&ident).unwrap();
2534 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2538 resolve_error(self, param.ident.span, err);
2540 seen_bindings.entry(ident).or_insert(param.ident.span);
2542 // Plain insert (no renaming).
2543 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2544 function_type_rib.bindings.insert(ident, def);
2545 self.record_def(param.id, PathResolution::new(def));
2549 self.ribs[TypeNS].push(function_type_rib);
2552 NoTypeParameters => {
2559 if let HasTypeParameters(..) = type_parameters {
2560 self.ribs[TypeNS].pop();
2564 fn with_label_rib<F>(&mut self, f: F)
2565 where F: FnOnce(&mut Resolver)
2567 self.label_ribs.push(Rib::new(NormalRibKind));
2569 self.label_ribs.pop();
2572 fn with_item_rib<F>(&mut self, f: F)
2573 where F: FnOnce(&mut Resolver)
2575 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2576 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2578 self.ribs[TypeNS].pop();
2579 self.ribs[ValueNS].pop();
2582 fn with_constant_rib<F>(&mut self, f: F)
2583 where F: FnOnce(&mut Resolver)
2585 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2586 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2588 self.label_ribs.pop();
2589 self.ribs[ValueNS].pop();
2592 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2593 where F: FnOnce(&mut Resolver) -> T
2595 // Handle nested impls (inside fn bodies)
2596 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2597 let result = f(self);
2598 self.current_self_type = previous_value;
2602 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2603 where F: FnOnce(&mut Resolver) -> T
2605 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2606 let result = f(self);
2607 self.current_self_item = previous_value;
2611 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2612 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2613 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2615 let mut new_val = None;
2616 let mut new_id = None;
2617 if let Some(trait_ref) = opt_trait_ref {
2618 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2619 let def = self.smart_resolve_path_fragment(
2623 trait_ref.path.span,
2624 PathSource::Trait(AliasPossibility::No),
2625 CrateLint::SimplePath(trait_ref.ref_id),
2627 if def != Def::Err {
2628 new_id = Some(def.def_id());
2629 let span = trait_ref.path.span;
2630 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2631 self.resolve_path_without_parent_scope(
2636 CrateLint::SimplePath(trait_ref.ref_id),
2639 new_val = Some((module, trait_ref.clone()));
2643 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2644 let result = f(self, new_id);
2645 self.current_trait_ref = original_trait_ref;
2649 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2650 where F: FnOnce(&mut Resolver)
2652 let mut self_type_rib = Rib::new(NormalRibKind);
2654 // plain insert (no renaming, types are not currently hygienic....)
2655 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2656 self.ribs[TypeNS].push(self_type_rib);
2658 self.ribs[TypeNS].pop();
2661 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2662 where F: FnOnce(&mut Resolver)
2664 let self_def = Def::SelfCtor(impl_id);
2665 let mut self_type_rib = Rib::new(NormalRibKind);
2666 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2667 self.ribs[ValueNS].push(self_type_rib);
2669 self.ribs[ValueNS].pop();
2672 fn resolve_implementation(&mut self,
2673 generics: &Generics,
2674 opt_trait_reference: &Option<TraitRef>,
2677 impl_items: &[ImplItem]) {
2678 // If applicable, create a rib for the type parameters.
2679 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2680 // Dummy self type for better errors if `Self` is used in the trait path.
2681 this.with_self_rib(Def::SelfTy(None, None), |this| {
2682 // Resolve the trait reference, if necessary.
2683 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2684 let item_def_id = this.definitions.local_def_id(item_id);
2685 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2686 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2687 // Resolve type arguments in the trait path.
2688 visit::walk_trait_ref(this, trait_ref);
2690 // Resolve the self type.
2691 this.visit_ty(self_type);
2692 // Resolve the type parameters.
2693 this.visit_generics(generics);
2694 // Resolve the items within the impl.
2695 this.with_current_self_type(self_type, |this| {
2696 this.with_self_struct_ctor_rib(item_def_id, |this| {
2697 for impl_item in impl_items {
2698 this.resolve_visibility(&impl_item.vis);
2700 // We also need a new scope for the impl item type parameters.
2701 let type_parameters = HasTypeParameters(&impl_item.generics,
2702 TraitOrImplItemRibKind);
2703 this.with_type_parameter_rib(type_parameters, |this| {
2704 use self::ResolutionError::*;
2705 match impl_item.node {
2706 ImplItemKind::Const(..) => {
2707 // If this is a trait impl, ensure the const
2709 this.check_trait_item(impl_item.ident,
2712 |n, s| ConstNotMemberOfTrait(n, s));
2713 this.with_constant_rib(|this|
2714 visit::walk_impl_item(this, impl_item)
2717 ImplItemKind::Method(..) => {
2718 // If this is a trait impl, ensure the method
2720 this.check_trait_item(impl_item.ident,
2723 |n, s| MethodNotMemberOfTrait(n, s));
2725 visit::walk_impl_item(this, impl_item);
2727 ImplItemKind::Type(ref ty) => {
2728 // If this is a trait impl, ensure the type
2730 this.check_trait_item(impl_item.ident,
2733 |n, s| TypeNotMemberOfTrait(n, s));
2737 ImplItemKind::Existential(ref bounds) => {
2738 // If this is a trait impl, ensure the type
2740 this.check_trait_item(impl_item.ident,
2743 |n, s| TypeNotMemberOfTrait(n, s));
2745 for bound in bounds {
2746 this.visit_param_bound(bound);
2749 ImplItemKind::Macro(_) =>
2750 panic!("unexpanded macro in resolve!"),
2762 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2763 where F: FnOnce(Name, &str) -> ResolutionError
2765 // If there is a TraitRef in scope for an impl, then the method must be in the
2767 if let Some((module, _)) = self.current_trait_ref {
2768 if self.resolve_ident_in_module(
2769 ModuleOrUniformRoot::Module(module),
2776 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2777 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2782 fn resolve_local(&mut self, local: &Local) {
2783 // Resolve the type.
2784 walk_list!(self, visit_ty, &local.ty);
2786 // Resolve the initializer.
2787 walk_list!(self, visit_expr, &local.init);
2789 // Resolve the pattern.
2790 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2793 // build a map from pattern identifiers to binding-info's.
2794 // this is done hygienically. This could arise for a macro
2795 // that expands into an or-pattern where one 'x' was from the
2796 // user and one 'x' came from the macro.
2797 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2798 let mut binding_map = FxHashMap::default();
2800 pat.walk(&mut |pat| {
2801 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2802 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2803 Some(Def::Local(..)) => true,
2806 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2807 binding_map.insert(ident, binding_info);
2816 // check that all of the arms in an or-pattern have exactly the
2817 // same set of bindings, with the same binding modes for each.
2818 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2819 if pats.is_empty() {
2823 let mut missing_vars = FxHashMap::default();
2824 let mut inconsistent_vars = FxHashMap::default();
2825 for (i, p) in pats.iter().enumerate() {
2826 let map_i = self.binding_mode_map(&p);
2828 for (j, q) in pats.iter().enumerate() {
2833 let map_j = self.binding_mode_map(&q);
2834 for (&key, &binding_i) in &map_i {
2835 if map_j.is_empty() { // Account for missing bindings when
2836 let binding_error = missing_vars // map_j has none.
2838 .or_insert(BindingError {
2840 origin: BTreeSet::new(),
2841 target: BTreeSet::new(),
2843 binding_error.origin.insert(binding_i.span);
2844 binding_error.target.insert(q.span);
2846 for (&key_j, &binding_j) in &map_j {
2847 match map_i.get(&key_j) {
2848 None => { // missing binding
2849 let binding_error = missing_vars
2851 .or_insert(BindingError {
2853 origin: BTreeSet::new(),
2854 target: BTreeSet::new(),
2856 binding_error.origin.insert(binding_j.span);
2857 binding_error.target.insert(p.span);
2859 Some(binding_i) => { // check consistent binding
2860 if binding_i.binding_mode != binding_j.binding_mode {
2863 .or_insert((binding_j.span, binding_i.span));
2871 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2872 missing_vars.sort();
2873 for (_, v) in missing_vars {
2875 *v.origin.iter().next().unwrap(),
2876 ResolutionError::VariableNotBoundInPattern(v));
2878 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2879 inconsistent_vars.sort();
2880 for (name, v) in inconsistent_vars {
2881 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2885 fn resolve_arm(&mut self, arm: &Arm) {
2886 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2888 let mut bindings_list = FxHashMap::default();
2889 for pattern in &arm.pats {
2890 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2893 // This has to happen *after* we determine which pat_idents are variants.
2894 self.check_consistent_bindings(&arm.pats);
2896 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2897 self.visit_expr(expr)
2899 self.visit_expr(&arm.body);
2901 self.ribs[ValueNS].pop();
2904 fn resolve_block(&mut self, block: &Block) {
2905 debug!("(resolving block) entering block");
2906 // Move down in the graph, if there's an anonymous module rooted here.
2907 let orig_module = self.current_module;
2908 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2910 let mut num_macro_definition_ribs = 0;
2911 if let Some(anonymous_module) = anonymous_module {
2912 debug!("(resolving block) found anonymous module, moving down");
2913 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2914 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2915 self.current_module = anonymous_module;
2916 self.finalize_current_module_macro_resolutions();
2918 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2921 // Descend into the block.
2922 for stmt in &block.stmts {
2923 if let ast::StmtKind::Item(ref item) = stmt.node {
2924 if let ast::ItemKind::MacroDef(..) = item.node {
2925 num_macro_definition_ribs += 1;
2926 let def = self.definitions.local_def_id(item.id);
2927 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2928 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2932 self.visit_stmt(stmt);
2936 self.current_module = orig_module;
2937 for _ in 0 .. num_macro_definition_ribs {
2938 self.ribs[ValueNS].pop();
2939 self.label_ribs.pop();
2941 self.ribs[ValueNS].pop();
2942 if anonymous_module.is_some() {
2943 self.ribs[TypeNS].pop();
2945 debug!("(resolving block) leaving block");
2948 fn fresh_binding(&mut self,
2951 outer_pat_id: NodeId,
2952 pat_src: PatternSource,
2953 bindings: &mut FxHashMap<Ident, NodeId>)
2955 // Add the binding to the local ribs, if it
2956 // doesn't already exist in the bindings map. (We
2957 // must not add it if it's in the bindings map
2958 // because that breaks the assumptions later
2959 // passes make about or-patterns.)
2960 let ident = ident.modern_and_legacy();
2961 let mut def = Def::Local(pat_id);
2962 match bindings.get(&ident).cloned() {
2963 Some(id) if id == outer_pat_id => {
2964 // `Variant(a, a)`, error
2968 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2972 Some(..) if pat_src == PatternSource::FnParam => {
2973 // `fn f(a: u8, a: u8)`, error
2977 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2981 Some(..) if pat_src == PatternSource::Match ||
2982 pat_src == PatternSource::IfLet ||
2983 pat_src == PatternSource::WhileLet => {
2984 // `Variant1(a) | Variant2(a)`, ok
2985 // Reuse definition from the first `a`.
2986 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2989 span_bug!(ident.span, "two bindings with the same name from \
2990 unexpected pattern source {:?}", pat_src);
2993 // A completely fresh binding, add to the lists if it's valid.
2994 if ident.name != keywords::Invalid.name() {
2995 bindings.insert(ident, outer_pat_id);
2996 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3001 PathResolution::new(def)
3004 fn resolve_pattern(&mut self,
3006 pat_src: PatternSource,
3007 // Maps idents to the node ID for the
3008 // outermost pattern that binds them.
3009 bindings: &mut FxHashMap<Ident, NodeId>) {
3010 // Visit all direct subpatterns of this pattern.
3011 let outer_pat_id = pat.id;
3012 pat.walk(&mut |pat| {
3014 PatKind::Ident(bmode, ident, ref opt_pat) => {
3015 // First try to resolve the identifier as some existing
3016 // entity, then fall back to a fresh binding.
3017 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3019 .and_then(LexicalScopeBinding::item);
3020 let resolution = binding.map(NameBinding::def).and_then(|def| {
3021 let is_syntactic_ambiguity = opt_pat.is_none() &&
3022 bmode == BindingMode::ByValue(Mutability::Immutable);
3024 Def::StructCtor(_, CtorKind::Const) |
3025 Def::VariantCtor(_, CtorKind::Const) |
3026 Def::Const(..) if is_syntactic_ambiguity => {
3027 // Disambiguate in favor of a unit struct/variant
3028 // or constant pattern.
3029 self.record_use(ident, ValueNS, binding.unwrap(), false);
3030 Some(PathResolution::new(def))
3032 Def::StructCtor(..) | Def::VariantCtor(..) |
3033 Def::Const(..) | Def::Static(..) => {
3034 // This is unambiguously a fresh binding, either syntactically
3035 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3036 // to something unusable as a pattern (e.g., constructor function),
3037 // but we still conservatively report an error, see
3038 // issues/33118#issuecomment-233962221 for one reason why.
3042 ResolutionError::BindingShadowsSomethingUnacceptable(
3043 pat_src.descr(), ident.name, binding.unwrap())
3047 Def::Fn(..) | Def::Err => {
3048 // These entities are explicitly allowed
3049 // to be shadowed by fresh bindings.
3053 span_bug!(ident.span, "unexpected definition for an \
3054 identifier in pattern: {:?}", def);
3057 }).unwrap_or_else(|| {
3058 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3061 self.record_def(pat.id, resolution);
3064 PatKind::TupleStruct(ref path, ..) => {
3065 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3068 PatKind::Path(ref qself, ref path) => {
3069 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3072 PatKind::Struct(ref path, ..) => {
3073 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3081 visit::walk_pat(self, pat);
3084 // High-level and context dependent path resolution routine.
3085 // Resolves the path and records the resolution into definition map.
3086 // If resolution fails tries several techniques to find likely
3087 // resolution candidates, suggest imports or other help, and report
3088 // errors in user friendly way.
3089 fn smart_resolve_path(&mut self,
3091 qself: Option<&QSelf>,
3095 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3098 /// A variant of `smart_resolve_path` where you also specify extra
3099 /// information about where the path came from; this extra info is
3100 /// sometimes needed for the lint that recommends rewriting
3101 /// absolute paths to `crate`, so that it knows how to frame the
3102 /// suggestion. If you are just resolving a path like `foo::bar`
3103 /// that appears...somewhere, though, then you just want
3104 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3105 /// already provides.
3106 fn smart_resolve_path_with_crate_lint(
3109 qself: Option<&QSelf>,
3112 crate_lint: CrateLint
3113 ) -> PathResolution {
3114 self.smart_resolve_path_fragment(
3117 &Segment::from_path(path),
3124 fn smart_resolve_path_fragment(&mut self,
3126 qself: Option<&QSelf>,
3130 crate_lint: CrateLint)
3132 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3133 let ns = source.namespace();
3134 let is_expected = &|def| source.is_expected(def);
3135 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3137 // Base error is amended with one short label and possibly some longer helps/notes.
3138 let report_errors = |this: &mut Self, def: Option<Def>| {
3139 // Make the base error.
3140 let expected = source.descr_expected();
3141 let path_str = Segment::names_to_string(path);
3142 let item_str = path.last().unwrap().ident;
3143 let code = source.error_code(def.is_some());
3144 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3145 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3146 format!("not a {}", expected),
3149 let item_span = path.last().unwrap().ident.span;
3150 let (mod_prefix, mod_str) = if path.len() == 1 {
3151 (String::new(), "this scope".to_string())
3152 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3153 (String::new(), "the crate root".to_string())
3155 let mod_path = &path[..path.len() - 1];
3156 let mod_prefix = match this.resolve_path_without_parent_scope(
3157 mod_path, Some(TypeNS), false, span, CrateLint::No
3159 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3162 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3163 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3165 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3166 format!("not found in {}", mod_str),
3169 let code = DiagnosticId::Error(code.into());
3170 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3172 // Emit help message for fake-self from other languages like `this`(javascript)
3173 if ["this", "my"].contains(&&*item_str.as_str())
3174 && this.self_value_is_available(path[0].ident.span, span) {
3175 err.span_suggestion_with_applicability(
3179 Applicability::MaybeIncorrect,
3183 // Emit special messages for unresolved `Self` and `self`.
3184 if is_self_type(path, ns) {
3185 __diagnostic_used!(E0411);
3186 err.code(DiagnosticId::Error("E0411".into()));
3187 err.span_label(span, format!("`Self` is only available in impls, traits, \
3188 and type definitions"));
3189 return (err, Vec::new());
3191 if is_self_value(path, ns) {
3192 __diagnostic_used!(E0424);
3193 err.code(DiagnosticId::Error("E0424".into()));
3194 err.span_label(span, format!("`self` value is a keyword \
3196 methods with `self` parameter"));
3197 return (err, Vec::new());
3200 // Try to lookup the name in more relaxed fashion for better error reporting.
3201 let ident = path.last().unwrap().ident;
3202 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3203 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3204 let enum_candidates =
3205 this.lookup_import_candidates(ident, ns, is_enum_variant);
3206 let mut enum_candidates = enum_candidates.iter()
3207 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3208 enum_candidates.sort();
3209 for (sp, variant_path, enum_path) in enum_candidates {
3211 let msg = format!("there is an enum variant `{}`, \
3217 err.span_suggestion_with_applicability(
3219 "you can try using the variant's enum",
3221 Applicability::MachineApplicable,
3226 if path.len() == 1 && this.self_type_is_available(span) {
3227 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3228 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3230 AssocSuggestion::Field => {
3231 err.span_suggestion_with_applicability(
3234 format!("self.{}", path_str),
3235 Applicability::MachineApplicable,
3237 if !self_is_available {
3238 err.span_label(span, format!("`self` value is a keyword \
3240 methods with `self` parameter"));
3243 AssocSuggestion::MethodWithSelf if self_is_available => {
3244 err.span_suggestion_with_applicability(
3247 format!("self.{}", path_str),
3248 Applicability::MachineApplicable,
3251 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3252 err.span_suggestion_with_applicability(
3255 format!("Self::{}", path_str),
3256 Applicability::MachineApplicable,
3260 return (err, candidates);
3264 let mut levenshtein_worked = false;
3266 // Try Levenshtein algorithm.
3267 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3268 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3269 levenshtein_worked = true;
3272 // Try context dependent help if relaxed lookup didn't work.
3273 if let Some(def) = def {
3274 match (def, source) {
3275 (Def::Macro(..), _) => {
3276 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3277 return (err, candidates);
3279 (Def::TyAlias(..), PathSource::Trait(_)) => {
3280 err.span_label(span, "type aliases cannot be used as traits");
3281 if nightly_options::is_nightly_build() {
3282 err.note("did you mean to use a trait alias?");
3284 return (err, candidates);
3286 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3287 ExprKind::Field(_, ident) => {
3288 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3290 return (err, candidates);
3292 ExprKind::MethodCall(ref segment, ..) => {
3293 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3294 path_str, segment.ident));
3295 return (err, candidates);
3299 (Def::Enum(..), PathSource::TupleStruct)
3300 | (Def::Enum(..), PathSource::Expr(..)) => {
3301 if let Some(variants) = this.collect_enum_variants(def) {
3302 err.note(&format!("did you mean to use one \
3303 of the following variants?\n{}",
3305 .map(|suggestion| path_names_to_string(suggestion))
3306 .map(|suggestion| format!("- `{}`", suggestion))
3307 .collect::<Vec<_>>()
3311 err.note("did you mean to use one of the enum's variants?");
3313 return (err, candidates);
3315 (Def::Struct(def_id), _) if ns == ValueNS => {
3316 if let Some((ctor_def, ctor_vis))
3317 = this.struct_constructors.get(&def_id).cloned() {
3318 let accessible_ctor = this.is_accessible(ctor_vis);
3319 if is_expected(ctor_def) && !accessible_ctor {
3320 err.span_label(span, format!("constructor is not visible \
3321 here due to private fields"));
3324 // HACK(estebank): find a better way to figure out that this was a
3325 // parser issue where a struct literal is being used on an expression
3326 // where a brace being opened means a block is being started. Look
3327 // ahead for the next text to see if `span` is followed by a `{`.
3328 let sm = this.session.source_map();
3331 sp = sm.next_point(sp);
3332 match sm.span_to_snippet(sp) {
3333 Ok(ref snippet) => {
3334 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3341 let followed_by_brace = match sm.span_to_snippet(sp) {
3342 Ok(ref snippet) if snippet == "{" => true,
3346 PathSource::Expr(Some(parent)) => {
3348 ExprKind::MethodCall(ref path_assignment, _) => {
3349 err.span_suggestion_with_applicability(
3350 sm.start_point(parent.span)
3351 .to(path_assignment.ident.span),
3352 "use `::` to access an associated function",
3355 path_assignment.ident),
3356 Applicability::MaybeIncorrect
3358 return (err, candidates);
3363 format!("did you mean `{} {{ /* fields */ }}`?",
3366 return (err, candidates);
3370 PathSource::Expr(None) if followed_by_brace == true => {
3373 format!("did you mean `({} {{ /* fields */ }})`?",
3376 return (err, candidates);
3381 format!("did you mean `{} {{ /* fields */ }}`?",
3384 return (err, candidates);
3388 return (err, candidates);
3390 (Def::Union(..), _) |
3391 (Def::Variant(..), _) |
3392 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3393 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3395 return (err, candidates);
3397 (Def::SelfTy(..), _) if ns == ValueNS => {
3398 err.span_label(span, fallback_label);
3399 err.note("can't use `Self` as a constructor, you must use the \
3400 implemented struct");
3401 return (err, candidates);
3403 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3404 err.note("can't use a type alias as a constructor");
3405 return (err, candidates);
3412 if !levenshtein_worked {
3413 err.span_label(base_span, fallback_label);
3414 this.type_ascription_suggestion(&mut err, base_span);
3418 let report_errors = |this: &mut Self, def: Option<Def>| {
3419 let (err, candidates) = report_errors(this, def);
3420 let def_id = this.current_module.normal_ancestor_id;
3421 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3422 let better = def.is_some();
3423 this.use_injections.push(UseError { err, candidates, node_id, better });
3424 err_path_resolution()
3427 let resolution = match self.resolve_qpath_anywhere(
3433 source.defer_to_typeck(),
3434 source.global_by_default(),
3437 Some(resolution) if resolution.unresolved_segments() == 0 => {
3438 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3441 // Add a temporary hack to smooth the transition to new struct ctor
3442 // visibility rules. See #38932 for more details.
3444 if let Def::Struct(def_id) = resolution.base_def() {
3445 if let Some((ctor_def, ctor_vis))
3446 = self.struct_constructors.get(&def_id).cloned() {
3447 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3448 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3449 self.session.buffer_lint(lint, id, span,
3450 "private struct constructors are not usable through \
3451 re-exports in outer modules",
3453 res = Some(PathResolution::new(ctor_def));
3458 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3461 Some(resolution) if source.defer_to_typeck() => {
3462 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3463 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3464 // it needs to be added to the trait map.
3466 let item_name = path.last().unwrap().ident;
3467 let traits = self.get_traits_containing_item(item_name, ns);
3468 self.trait_map.insert(id, traits);
3472 _ => report_errors(self, None)
3475 if let PathSource::TraitItem(..) = source {} else {
3476 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3477 self.record_def(id, resolution);
3482 fn type_ascription_suggestion(&self,
3483 err: &mut DiagnosticBuilder,
3485 debug!("type_ascription_suggetion {:?}", base_span);
3486 let cm = self.session.source_map();
3487 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3488 if let Some(sp) = self.current_type_ascription.last() {
3490 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3491 sp = cm.next_point(sp);
3492 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3493 debug!("snippet {:?}", snippet);
3494 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3495 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3496 debug!("{:?} {:?}", line_sp, line_base_sp);
3498 err.span_label(base_span,
3499 "expecting a type here because of type ascription");
3500 if line_sp != line_base_sp {
3501 err.span_suggestion_short_with_applicability(
3503 "did you mean to use `;` here instead?",
3505 Applicability::MaybeIncorrect,
3509 } else if !snippet.trim().is_empty() {
3510 debug!("tried to find type ascription `:` token, couldn't find it");
3520 fn self_type_is_available(&mut self, span: Span) -> bool {
3521 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3522 TypeNS, None, span);
3523 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3526 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3527 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3528 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3529 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3532 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3533 fn resolve_qpath_anywhere(&mut self,
3535 qself: Option<&QSelf>,
3537 primary_ns: Namespace,
3539 defer_to_typeck: bool,
3540 global_by_default: bool,
3541 crate_lint: CrateLint)
3542 -> Option<PathResolution> {
3543 let mut fin_res = None;
3544 // FIXME: can't resolve paths in macro namespace yet, macros are
3545 // processed by the little special hack below.
3546 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3547 if i == 0 || ns != primary_ns {
3548 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3549 // If defer_to_typeck, then resolution > no resolution,
3550 // otherwise full resolution > partial resolution > no resolution.
3551 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3553 res => if fin_res.is_none() { fin_res = res },
3557 if primary_ns != MacroNS &&
3558 (self.macro_names.contains(&path[0].ident.modern()) ||
3559 self.builtin_macros.get(&path[0].ident.name).cloned()
3560 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3561 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3562 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3563 // Return some dummy definition, it's enough for error reporting.
3565 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3571 /// Handles paths that may refer to associated items.
3572 fn resolve_qpath(&mut self,
3574 qself: Option<&QSelf>,
3578 global_by_default: bool,
3579 crate_lint: CrateLint)
3580 -> Option<PathResolution> {
3582 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3583 ns={:?}, span={:?}, global_by_default={:?})",
3592 if let Some(qself) = qself {
3593 if qself.position == 0 {
3594 // This is a case like `<T>::B`, where there is no
3595 // trait to resolve. In that case, we leave the `B`
3596 // segment to be resolved by type-check.
3597 return Some(PathResolution::with_unresolved_segments(
3598 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3602 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3604 // Currently, `path` names the full item (`A::B::C`, in
3605 // our example). so we extract the prefix of that that is
3606 // the trait (the slice upto and including
3607 // `qself.position`). And then we recursively resolve that,
3608 // but with `qself` set to `None`.
3610 // However, setting `qself` to none (but not changing the
3611 // span) loses the information about where this path
3612 // *actually* appears, so for the purposes of the crate
3613 // lint we pass along information that this is the trait
3614 // name from a fully qualified path, and this also
3615 // contains the full span (the `CrateLint::QPathTrait`).
3616 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3617 let res = self.smart_resolve_path_fragment(
3620 &path[..=qself.position],
3622 PathSource::TraitItem(ns),
3623 CrateLint::QPathTrait {
3625 qpath_span: qself.path_span,
3629 // The remaining segments (the `C` in our example) will
3630 // have to be resolved by type-check, since that requires doing
3631 // trait resolution.
3632 return Some(PathResolution::with_unresolved_segments(
3633 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3637 let result = match self.resolve_path_without_parent_scope(
3644 PathResult::NonModule(path_res) => path_res,
3645 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3646 PathResolution::new(module.def().unwrap())
3648 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3649 // don't report an error right away, but try to fallback to a primitive type.
3650 // So, we are still able to successfully resolve something like
3652 // use std::u8; // bring module u8 in scope
3653 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3654 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3655 // // not to non-existent std::u8::max_value
3658 // Such behavior is required for backward compatibility.
3659 // The same fallback is used when `a` resolves to nothing.
3660 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3661 PathResult::Failed(..)
3662 if (ns == TypeNS || path.len() > 1) &&
3663 self.primitive_type_table.primitive_types
3664 .contains_key(&path[0].ident.name) => {
3665 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3666 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3668 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3669 PathResolution::new(module.def().unwrap()),
3670 PathResult::Failed(span, msg, false) => {
3671 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3672 err_path_resolution()
3674 PathResult::Module(..) | PathResult::Failed(..) => return None,
3675 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3678 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3679 path[0].ident.name != keywords::PathRoot.name() &&
3680 path[0].ident.name != keywords::DollarCrate.name() {
3681 let unqualified_result = {
3682 match self.resolve_path_without_parent_scope(
3683 &[*path.last().unwrap()],
3689 PathResult::NonModule(path_res) => path_res.base_def(),
3690 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3691 module.def().unwrap(),
3692 _ => return Some(result),
3695 if result.base_def() == unqualified_result {
3696 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3697 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3704 fn resolve_path_without_parent_scope(
3707 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3710 crate_lint: CrateLint,
3711 ) -> PathResult<'a> {
3712 // Macro and import paths must have full parent scope available during resolution,
3713 // other paths will do okay with parent module alone.
3714 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3715 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3716 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3722 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3723 parent_scope: &ParentScope<'a>,
3726 crate_lint: CrateLint,
3727 ) -> PathResult<'a> {
3728 let mut module = None;
3729 let mut allow_super = true;
3730 let mut second_binding = None;
3731 self.current_module = parent_scope.module;
3734 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3735 path_span={:?}, crate_lint={:?})",
3743 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3744 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3745 let record_segment_def = |this: &mut Self, def| {
3747 if let Some(id) = id {
3748 if !this.def_map.contains_key(&id) {
3749 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3750 this.record_def(id, PathResolution::new(def));
3756 let is_last = i == path.len() - 1;
3757 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3758 let name = ident.name;
3760 allow_super &= ns == TypeNS &&
3761 (name == keywords::SelfLower.name() ||
3762 name == keywords::Super.name());
3765 if allow_super && name == keywords::Super.name() {
3766 let mut ctxt = ident.span.ctxt().modern();
3767 let self_module = match i {
3768 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3770 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3774 if let Some(self_module) = self_module {
3775 if let Some(parent) = self_module.parent {
3776 module = Some(ModuleOrUniformRoot::Module(
3777 self.resolve_self(&mut ctxt, parent)));
3781 let msg = "there are too many initial `super`s.".to_string();
3782 return PathResult::Failed(ident.span, msg, false);
3785 if name == keywords::SelfLower.name() {
3786 let mut ctxt = ident.span.ctxt().modern();
3787 module = Some(ModuleOrUniformRoot::Module(
3788 self.resolve_self(&mut ctxt, self.current_module)));
3791 if name == keywords::Extern.name() ||
3792 name == keywords::PathRoot.name() && ident.span.rust_2018() {
3793 module = Some(ModuleOrUniformRoot::ExternPrelude);
3796 if name == keywords::PathRoot.name() &&
3797 ident.span.rust_2015() && self.session.rust_2018() {
3798 // `::a::b` from 2015 macro on 2018 global edition
3799 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3802 if name == keywords::PathRoot.name() ||
3803 name == keywords::Crate.name() ||
3804 name == keywords::DollarCrate.name() {
3805 // `::a::b`, `crate::a::b` or `$crate::a::b`
3806 module = Some(ModuleOrUniformRoot::Module(
3807 self.resolve_crate_root(ident)));
3813 // Report special messages for path segment keywords in wrong positions.
3814 if ident.is_path_segment_keyword() && i != 0 {
3815 let name_str = if name == keywords::PathRoot.name() {
3816 "crate root".to_string()
3818 format!("`{}`", name)
3820 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3821 format!("global paths cannot start with {}", name_str)
3823 format!("{} in paths can only be used in start position", name_str)
3825 return PathResult::Failed(ident.span, msg, false);
3828 let binding = if let Some(module) = module {
3829 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3830 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3831 assert!(ns == TypeNS);
3832 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3833 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3834 record_used, path_span)
3836 let record_used_id =
3837 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3838 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3839 // we found a locally-imported or available item/module
3840 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3841 // we found a local variable or type param
3842 Some(LexicalScopeBinding::Def(def))
3843 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3844 record_segment_def(self, def);
3845 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3849 _ => Err(Determinacy::determined(record_used)),
3856 second_binding = Some(binding);
3858 let def = binding.def();
3859 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3860 if let Some(next_module) = binding.module() {
3861 module = Some(ModuleOrUniformRoot::Module(next_module));
3862 record_segment_def(self, def);
3863 } else if def == Def::ToolMod && i + 1 != path.len() {
3864 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3865 return PathResult::NonModule(PathResolution::new(def));
3866 } else if def == Def::Err {
3867 return PathResult::NonModule(err_path_resolution());
3868 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3869 self.lint_if_path_starts_with_module(
3875 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3876 def, path.len() - i - 1
3879 return PathResult::Failed(ident.span,
3880 format!("not a module `{}`", ident),
3884 Err(Undetermined) => return PathResult::Indeterminate,
3885 Err(Determined) => {
3886 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3887 if opt_ns.is_some() && !module.is_normal() {
3888 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3889 module.def().unwrap(), path.len() - i
3893 let module_def = match module {
3894 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3897 let msg = if module_def == self.graph_root.def() {
3898 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3899 let mut candidates =
3900 self.lookup_import_candidates(ident, TypeNS, is_mod);
3901 candidates.sort_by_cached_key(|c| {
3902 (c.path.segments.len(), c.path.to_string())
3904 if let Some(candidate) = candidates.get(0) {
3905 format!("did you mean `{}`?", candidate.path)
3907 format!("maybe a missing `extern crate {};`?", ident)
3910 format!("use of undeclared type or module `{}`", ident)
3912 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
3914 return PathResult::Failed(ident.span, msg, is_last);
3919 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3921 PathResult::Module(match module {
3922 Some(module) => module,
3923 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
3924 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
3928 fn lint_if_path_starts_with_module(
3930 crate_lint: CrateLint,
3933 second_binding: Option<&NameBinding>,
3935 let (diag_id, diag_span) = match crate_lint {
3936 CrateLint::No => return,
3937 CrateLint::SimplePath(id) => (id, path_span),
3938 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3939 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3942 let first_name = match path.get(0) {
3943 // In the 2018 edition this lint is a hard error, so nothing to do
3944 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
3948 // We're only interested in `use` paths which should start with
3949 // `{{root}}` or `extern` currently.
3950 if first_name != keywords::Extern.name() && first_name != keywords::PathRoot.name() {
3955 // If this import looks like `crate::...` it's already good
3956 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
3957 // Otherwise go below to see if it's an extern crate
3959 // If the path has length one (and it's `PathRoot` most likely)
3960 // then we don't know whether we're gonna be importing a crate or an
3961 // item in our crate. Defer this lint to elsewhere
3965 // If the first element of our path was actually resolved to an
3966 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3967 // warning, this looks all good!
3968 if let Some(binding) = second_binding {
3969 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3970 // Careful: we still want to rewrite paths from
3971 // renamed extern crates.
3972 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
3978 let diag = lint::builtin::BuiltinLintDiagnostics
3979 ::AbsPathWithModule(diag_span);
3980 self.session.buffer_lint_with_diagnostic(
3981 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3983 "absolute paths must start with `self`, `super`, \
3984 `crate`, or an external crate name in the 2018 edition",
3988 // Resolve a local definition, potentially adjusting for closures.
3989 fn adjust_local_def(&mut self,
3994 span: Span) -> Def {
3995 let ribs = &self.ribs[ns][rib_index + 1..];
3997 // An invalid forward use of a type parameter from a previous default.
3998 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4000 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4002 assert_eq!(def, Def::Err);
4008 span_bug!(span, "unexpected {:?} in bindings", def)
4010 Def::Local(node_id) => {
4013 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4014 ForwardTyParamBanRibKind => {
4015 // Nothing to do. Continue.
4017 ClosureRibKind(function_id) => {
4020 let seen = self.freevars_seen
4023 if let Some(&index) = seen.get(&node_id) {
4024 def = Def::Upvar(node_id, index, function_id);
4027 let vec = self.freevars
4030 let depth = vec.len();
4031 def = Def::Upvar(node_id, depth, function_id);
4038 seen.insert(node_id, depth);
4041 ItemRibKind | TraitOrImplItemRibKind => {
4042 // This was an attempt to access an upvar inside a
4043 // named function item. This is not allowed, so we
4046 resolve_error(self, span,
4047 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4051 ConstantItemRibKind => {
4052 // Still doesn't deal with upvars
4054 resolve_error(self, span,
4055 ResolutionError::AttemptToUseNonConstantValueInConstant);
4062 Def::TyParam(..) | Def::SelfTy(..) => {
4065 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4066 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4067 ConstantItemRibKind => {
4068 // Nothing to do. Continue.
4071 // This was an attempt to use a type parameter outside
4074 resolve_error(self, span,
4075 ResolutionError::TypeParametersFromOuterFunction(def));
4087 fn lookup_assoc_candidate<FilterFn>(&mut self,
4090 filter_fn: FilterFn)
4091 -> Option<AssocSuggestion>
4092 where FilterFn: Fn(Def) -> bool
4094 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4096 TyKind::Path(None, _) => Some(t.id),
4097 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4098 // This doesn't handle the remaining `Ty` variants as they are not
4099 // that commonly the self_type, it might be interesting to provide
4100 // support for those in future.
4105 // Fields are generally expected in the same contexts as locals.
4106 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4107 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4108 // Look for a field with the same name in the current self_type.
4109 if let Some(resolution) = self.def_map.get(&node_id) {
4110 match resolution.base_def() {
4111 Def::Struct(did) | Def::Union(did)
4112 if resolution.unresolved_segments() == 0 => {
4113 if let Some(field_names) = self.field_names.get(&did) {
4114 if field_names.iter().any(|&field_name| ident.name == field_name) {
4115 return Some(AssocSuggestion::Field);
4125 // Look for associated items in the current trait.
4126 if let Some((module, _)) = self.current_trait_ref {
4127 if let Ok(binding) = self.resolve_ident_in_module(
4128 ModuleOrUniformRoot::Module(module),
4135 let def = binding.def();
4137 return Some(if self.has_self.contains(&def.def_id()) {
4138 AssocSuggestion::MethodWithSelf
4140 AssocSuggestion::AssocItem
4149 fn lookup_typo_candidate<FilterFn>(&mut self,
4152 filter_fn: FilterFn,
4155 where FilterFn: Fn(Def) -> bool
4157 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
4158 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4159 if let Some(binding) = resolution.borrow().binding {
4160 if filter_fn(binding.def()) {
4161 names.push(ident.name);
4167 let mut names = Vec::new();
4168 if path.len() == 1 {
4169 // Search in lexical scope.
4170 // Walk backwards up the ribs in scope and collect candidates.
4171 for rib in self.ribs[ns].iter().rev() {
4172 // Locals and type parameters
4173 for (ident, def) in &rib.bindings {
4174 if filter_fn(*def) {
4175 names.push(ident.name);
4179 if let ModuleRibKind(module) = rib.kind {
4180 // Items from this module
4181 add_module_candidates(module, &mut names);
4183 if let ModuleKind::Block(..) = module.kind {
4184 // We can see through blocks
4186 // Items from the prelude
4187 if !module.no_implicit_prelude {
4188 names.extend(self.extern_prelude.iter().map(|(ident, _)| ident.name));
4189 if let Some(prelude) = self.prelude {
4190 add_module_candidates(prelude, &mut names);
4197 // Add primitive types to the mix
4198 if filter_fn(Def::PrimTy(Bool)) {
4200 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
4204 // Search in module.
4205 let mod_path = &path[..path.len() - 1];
4206 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4207 mod_path, Some(TypeNS), false, span, CrateLint::No
4209 if let ModuleOrUniformRoot::Module(module) = module {
4210 add_module_candidates(module, &mut names);
4215 let name = path[path.len() - 1].ident.name;
4216 // Make sure error reporting is deterministic.
4217 names.sort_by_cached_key(|name| name.as_str());
4218 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
4219 Some(found) if found != name => Some(found),
4224 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4225 where F: FnOnce(&mut Resolver)
4227 if let Some(label) = label {
4228 self.unused_labels.insert(id, label.ident.span);
4229 let def = Def::Label(id);
4230 self.with_label_rib(|this| {
4231 let ident = label.ident.modern_and_legacy();
4232 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4240 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4241 self.with_resolved_label(label, id, |this| this.visit_block(block));
4244 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4245 // First, record candidate traits for this expression if it could
4246 // result in the invocation of a method call.
4248 self.record_candidate_traits_for_expr_if_necessary(expr);
4250 // Next, resolve the node.
4252 ExprKind::Path(ref qself, ref path) => {
4253 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4254 visit::walk_expr(self, expr);
4257 ExprKind::Struct(ref path, ..) => {
4258 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4259 visit::walk_expr(self, expr);
4262 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4263 let def = self.search_label(label.ident, |rib, ident| {
4264 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4268 // Search again for close matches...
4269 // Picks the first label that is "close enough", which is not necessarily
4270 // the closest match
4271 let close_match = self.search_label(label.ident, |rib, ident| {
4272 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4273 find_best_match_for_name(names, &*ident.as_str(), None)
4275 self.record_def(expr.id, err_path_resolution());
4278 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4281 Some(Def::Label(id)) => {
4282 // Since this def is a label, it is never read.
4283 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4284 self.unused_labels.remove(&id);
4287 span_bug!(expr.span, "label wasn't mapped to a label def!");
4291 // visit `break` argument if any
4292 visit::walk_expr(self, expr);
4295 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4296 self.visit_expr(subexpression);
4298 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4299 let mut bindings_list = FxHashMap::default();
4301 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4303 // This has to happen *after* we determine which pat_idents are variants
4304 self.check_consistent_bindings(pats);
4305 self.visit_block(if_block);
4306 self.ribs[ValueNS].pop();
4308 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4311 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4313 ExprKind::While(ref subexpression, ref block, label) => {
4314 self.with_resolved_label(label, expr.id, |this| {
4315 this.visit_expr(subexpression);
4316 this.visit_block(block);
4320 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4321 self.with_resolved_label(label, expr.id, |this| {
4322 this.visit_expr(subexpression);
4323 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4324 let mut bindings_list = FxHashMap::default();
4326 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4328 // This has to happen *after* we determine which pat_idents are variants.
4329 this.check_consistent_bindings(pats);
4330 this.visit_block(block);
4331 this.ribs[ValueNS].pop();
4335 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4336 self.visit_expr(subexpression);
4337 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4338 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4340 self.resolve_labeled_block(label, expr.id, block);
4342 self.ribs[ValueNS].pop();
4345 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4347 // Equivalent to `visit::walk_expr` + passing some context to children.
4348 ExprKind::Field(ref subexpression, _) => {
4349 self.resolve_expr(subexpression, Some(expr));
4351 ExprKind::MethodCall(ref segment, ref arguments) => {
4352 let mut arguments = arguments.iter();
4353 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4354 for argument in arguments {
4355 self.resolve_expr(argument, None);
4357 self.visit_path_segment(expr.span, segment);
4360 ExprKind::Call(ref callee, ref arguments) => {
4361 self.resolve_expr(callee, Some(expr));
4362 for argument in arguments {
4363 self.resolve_expr(argument, None);
4366 ExprKind::Type(ref type_expr, _) => {
4367 self.current_type_ascription.push(type_expr.span);
4368 visit::walk_expr(self, expr);
4369 self.current_type_ascription.pop();
4371 // Resolve the body of async exprs inside the async closure to which they desugar
4372 ExprKind::Async(_, async_closure_id, ref block) => {
4373 let rib_kind = ClosureRibKind(async_closure_id);
4374 self.ribs[ValueNS].push(Rib::new(rib_kind));
4375 self.label_ribs.push(Rib::new(rib_kind));
4376 self.visit_block(&block);
4377 self.label_ribs.pop();
4378 self.ribs[ValueNS].pop();
4380 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4381 // resolve the arguments within the proper scopes so that usages of them inside the
4382 // closure are detected as upvars rather than normal closure arg usages.
4384 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4385 ref fn_decl, ref body, _span,
4387 let rib_kind = ClosureRibKind(expr.id);
4388 self.ribs[ValueNS].push(Rib::new(rib_kind));
4389 self.label_ribs.push(Rib::new(rib_kind));
4390 // Resolve arguments:
4391 let mut bindings_list = FxHashMap::default();
4392 for argument in &fn_decl.inputs {
4393 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4394 self.visit_ty(&argument.ty);
4396 // No need to resolve return type-- the outer closure return type is
4397 // FunctionRetTy::Default
4399 // Now resolve the inner closure
4401 let rib_kind = ClosureRibKind(inner_closure_id);
4402 self.ribs[ValueNS].push(Rib::new(rib_kind));
4403 self.label_ribs.push(Rib::new(rib_kind));
4404 // No need to resolve arguments: the inner closure has none.
4405 // Resolve the return type:
4406 visit::walk_fn_ret_ty(self, &fn_decl.output);
4408 self.visit_expr(body);
4409 self.label_ribs.pop();
4410 self.ribs[ValueNS].pop();
4412 self.label_ribs.pop();
4413 self.ribs[ValueNS].pop();
4416 visit::walk_expr(self, expr);
4421 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4423 ExprKind::Field(_, ident) => {
4424 // FIXME(#6890): Even though you can't treat a method like a
4425 // field, we need to add any trait methods we find that match
4426 // the field name so that we can do some nice error reporting
4427 // later on in typeck.
4428 let traits = self.get_traits_containing_item(ident, ValueNS);
4429 self.trait_map.insert(expr.id, traits);
4431 ExprKind::MethodCall(ref segment, ..) => {
4432 debug!("(recording candidate traits for expr) recording traits for {}",
4434 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4435 self.trait_map.insert(expr.id, traits);
4443 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4444 -> Vec<TraitCandidate> {
4445 debug!("(getting traits containing item) looking for '{}'", ident.name);
4447 let mut found_traits = Vec::new();
4448 // Look for the current trait.
4449 if let Some((module, _)) = self.current_trait_ref {
4450 if self.resolve_ident_in_module(
4451 ModuleOrUniformRoot::Module(module),
4458 let def_id = module.def_id().unwrap();
4459 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4463 ident.span = ident.span.modern();
4464 let mut search_module = self.current_module;
4466 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4467 search_module = unwrap_or!(
4468 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4472 if let Some(prelude) = self.prelude {
4473 if !search_module.no_implicit_prelude {
4474 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4481 fn get_traits_in_module_containing_item(&mut self,
4485 found_traits: &mut Vec<TraitCandidate>) {
4486 assert!(ns == TypeNS || ns == ValueNS);
4487 let mut traits = module.traits.borrow_mut();
4488 if traits.is_none() {
4489 let mut collected_traits = Vec::new();
4490 module.for_each_child(|name, ns, binding| {
4491 if ns != TypeNS { return }
4492 if let Def::Trait(_) = binding.def() {
4493 collected_traits.push((name, binding));
4496 *traits = Some(collected_traits.into_boxed_slice());
4499 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4500 let module = binding.module().unwrap();
4501 let mut ident = ident;
4502 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4505 if self.resolve_ident_in_module_unadjusted(
4506 ModuleOrUniformRoot::Module(module),
4512 let import_id = match binding.kind {
4513 NameBindingKind::Import { directive, .. } => {
4514 self.maybe_unused_trait_imports.insert(directive.id);
4515 self.add_to_glob_map(directive.id, trait_name);
4520 let trait_def_id = module.def_id().unwrap();
4521 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4526 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4527 lookup_ident: Ident,
4528 namespace: Namespace,
4529 start_module: &'a ModuleData<'a>,
4531 filter_fn: FilterFn)
4532 -> Vec<ImportSuggestion>
4533 where FilterFn: Fn(Def) -> bool
4535 let mut candidates = Vec::new();
4536 let mut seen_modules = FxHashSet::default();
4537 let not_local_module = crate_name != keywords::Crate.ident();
4538 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4540 while let Some((in_module,
4542 in_module_is_extern)) = worklist.pop() {
4543 self.populate_module_if_necessary(in_module);
4545 // We have to visit module children in deterministic order to avoid
4546 // instabilities in reported imports (#43552).
4547 in_module.for_each_child_stable(|ident, ns, name_binding| {
4548 // avoid imports entirely
4549 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4550 // avoid non-importable candidates as well
4551 if !name_binding.is_importable() { return; }
4553 // collect results based on the filter function
4554 if ident.name == lookup_ident.name && ns == namespace {
4555 if filter_fn(name_binding.def()) {
4557 let mut segms = path_segments.clone();
4558 if lookup_ident.span.rust_2018() {
4559 // crate-local absolute paths start with `crate::` in edition 2018
4560 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4562 0, ast::PathSegment::from_ident(crate_name)
4566 segms.push(ast::PathSegment::from_ident(ident));
4568 span: name_binding.span,
4571 // the entity is accessible in the following cases:
4572 // 1. if it's defined in the same crate, it's always
4573 // accessible (since private entities can be made public)
4574 // 2. if it's defined in another crate, it's accessible
4575 // only if both the module is public and the entity is
4576 // declared as public (due to pruning, we don't explore
4577 // outside crate private modules => no need to check this)
4578 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4579 candidates.push(ImportSuggestion { path });
4584 // collect submodules to explore
4585 if let Some(module) = name_binding.module() {
4587 let mut path_segments = path_segments.clone();
4588 path_segments.push(ast::PathSegment::from_ident(ident));
4590 let is_extern_crate_that_also_appears_in_prelude =
4591 name_binding.is_extern_crate() &&
4592 lookup_ident.span.rust_2018();
4594 let is_visible_to_user =
4595 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4597 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4598 // add the module to the lookup
4599 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4600 if seen_modules.insert(module.def_id().unwrap()) {
4601 worklist.push((module, path_segments, is_extern));
4611 /// When name resolution fails, this method can be used to look up candidate
4612 /// entities with the expected name. It allows filtering them using the
4613 /// supplied predicate (which should be used to only accept the types of
4614 /// definitions expected e.g., traits). The lookup spans across all crates.
4616 /// NOTE: The method does not look into imports, but this is not a problem,
4617 /// since we report the definitions (thus, the de-aliased imports).
4618 fn lookup_import_candidates<FilterFn>(&mut self,
4619 lookup_ident: Ident,
4620 namespace: Namespace,
4621 filter_fn: FilterFn)
4622 -> Vec<ImportSuggestion>
4623 where FilterFn: Fn(Def) -> bool
4625 let mut suggestions = self.lookup_import_candidates_from_module(
4626 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4628 if lookup_ident.span.rust_2018() {
4629 let extern_prelude_names = self.extern_prelude.clone();
4630 for (ident, _) in extern_prelude_names.into_iter() {
4631 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4633 let crate_root = self.get_module(DefId {
4635 index: CRATE_DEF_INDEX,
4637 self.populate_module_if_necessary(&crate_root);
4639 suggestions.extend(self.lookup_import_candidates_from_module(
4640 lookup_ident, namespace, crate_root, ident, &filter_fn));
4648 fn find_module(&mut self,
4650 -> Option<(Module<'a>, ImportSuggestion)>
4652 let mut result = None;
4653 let mut seen_modules = FxHashSet::default();
4654 let mut worklist = vec![(self.graph_root, Vec::new())];
4656 while let Some((in_module, path_segments)) = worklist.pop() {
4657 // abort if the module is already found
4658 if result.is_some() { break; }
4660 self.populate_module_if_necessary(in_module);
4662 in_module.for_each_child_stable(|ident, _, name_binding| {
4663 // abort if the module is already found or if name_binding is private external
4664 if result.is_some() || !name_binding.vis.is_visible_locally() {
4667 if let Some(module) = name_binding.module() {
4669 let mut path_segments = path_segments.clone();
4670 path_segments.push(ast::PathSegment::from_ident(ident));
4671 if module.def() == Some(module_def) {
4673 span: name_binding.span,
4674 segments: path_segments,
4676 result = Some((module, ImportSuggestion { path }));
4678 // add the module to the lookup
4679 if seen_modules.insert(module.def_id().unwrap()) {
4680 worklist.push((module, path_segments));
4690 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4691 if let Def::Enum(..) = enum_def {} else {
4692 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4695 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4696 self.populate_module_if_necessary(enum_module);
4698 let mut variants = Vec::new();
4699 enum_module.for_each_child_stable(|ident, _, name_binding| {
4700 if let Def::Variant(..) = name_binding.def() {
4701 let mut segms = enum_import_suggestion.path.segments.clone();
4702 segms.push(ast::PathSegment::from_ident(ident));
4703 variants.push(Path {
4704 span: name_binding.span,
4713 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4714 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4715 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4716 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4720 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4722 ast::VisibilityKind::Public => ty::Visibility::Public,
4723 ast::VisibilityKind::Crate(..) => {
4724 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4726 ast::VisibilityKind::Inherited => {
4727 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4729 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4730 // For visibilities we are not ready to provide correct implementation of "uniform
4731 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4732 // On 2015 edition visibilities are resolved as crate-relative by default,
4733 // so we are prepending a root segment if necessary.
4734 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4735 let crate_root = if ident.is_path_segment_keyword() {
4737 } else if ident.span.rust_2018() {
4738 let msg = "relative paths are not supported in visibilities on 2018 edition";
4739 self.session.struct_span_err(ident.span, msg)
4740 .span_suggestion(path.span, "try", format!("crate::{}", path))
4742 return ty::Visibility::Public;
4744 let ctxt = ident.span.ctxt();
4745 Some(Segment::from_ident(Ident::new(
4746 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4750 let segments = crate_root.into_iter()
4751 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4752 let def = self.smart_resolve_path_fragment(
4757 PathSource::Visibility,
4758 CrateLint::SimplePath(id),
4760 if def == Def::Err {
4761 ty::Visibility::Public
4763 let vis = ty::Visibility::Restricted(def.def_id());
4764 if self.is_accessible(vis) {
4767 self.session.span_err(path.span, "visibilities can only be restricted \
4768 to ancestor modules");
4769 ty::Visibility::Public
4776 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4777 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4780 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4781 vis.is_accessible_from(module.normal_ancestor_id, self)
4784 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4785 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4786 if !ptr::eq(module, old_module) {
4787 span_bug!(binding.span, "parent module is reset for binding");
4792 fn disambiguate_legacy_vs_modern(
4794 legacy: &'a NameBinding<'a>,
4795 modern: &'a NameBinding<'a>,
4797 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
4798 // is disambiguated to mitigate regressions from macro modularization.
4799 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
4800 match (self.binding_parent_modules.get(&PtrKey(legacy)),
4801 self.binding_parent_modules.get(&PtrKey(modern))) {
4802 (Some(legacy), Some(modern)) =>
4803 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
4804 modern.is_ancestor_of(legacy),
4809 fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
4810 if b.span.is_dummy() {
4811 let add_built_in = match b.def() {
4812 // These already contain the "built-in" prefix or look bad with it.
4813 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
4816 let (built_in, from) = if from_prelude {
4817 ("", " from prelude")
4818 } else if b.is_extern_crate() && !b.is_import() &&
4819 self.session.opts.externs.get(&ident.as_str()).is_some() {
4820 ("", " passed with `--extern`")
4821 } else if add_built_in {
4827 let article = if built_in.is_empty() { b.article() } else { "a" };
4828 format!("{a}{built_in} {thing}{from}",
4829 a = article, thing = b.descr(), built_in = built_in, from = from)
4831 let introduced = if b.is_import() { "imported" } else { "defined" };
4832 format!("the {thing} {introduced} here",
4833 thing = b.descr(), introduced = introduced)
4837 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
4838 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
4839 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
4840 // We have to print the span-less alternative first, otherwise formatting looks bad.
4841 (b2, b1, misc2, misc1, true)
4843 (b1, b2, misc1, misc2, false)
4846 let mut err = struct_span_err!(self.session, ident.span, E0659,
4847 "`{ident}` is ambiguous ({why})",
4848 ident = ident, why = kind.descr());
4849 err.span_label(ident.span, "ambiguous name");
4851 let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
4852 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
4853 let note_msg = format!("`{ident}` could{also} refer to {what}",
4854 ident = ident, also = also, what = what);
4856 let mut help_msgs = Vec::new();
4857 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
4858 kind == AmbiguityKind::GlobVsExpanded ||
4859 kind == AmbiguityKind::GlobVsOuter &&
4860 swapped != also.is_empty()) {
4861 help_msgs.push(format!("consider adding an explicit import of \
4862 `{ident}` to disambiguate", ident = ident))
4864 if b.is_extern_crate() && ident.span.rust_2018() {
4865 help_msgs.push(format!(
4866 "use `::{ident}` to refer to this {thing} unambiguously",
4867 ident = ident, thing = b.descr(),
4870 if misc == AmbiguityErrorMisc::SuggestCrate {
4871 help_msgs.push(format!(
4872 "use `crate::{ident}` to refer to this {thing} unambiguously",
4873 ident = ident, thing = b.descr(),
4875 } else if misc == AmbiguityErrorMisc::SuggestSelf {
4876 help_msgs.push(format!(
4877 "use `self::{ident}` to refer to this {thing} unambiguously",
4878 ident = ident, thing = b.descr(),
4882 if b.span.is_dummy() {
4883 err.note(¬e_msg);
4885 err.span_note(b.span, ¬e_msg);
4887 for (i, help_msg) in help_msgs.iter().enumerate() {
4888 let or = if i == 0 { "" } else { "or " };
4889 err.help(&format!("{}{}", or, help_msg));
4893 could_refer_to(b1, misc1, "");
4894 could_refer_to(b2, misc2, " also");
4898 fn report_errors(&mut self, krate: &Crate) {
4899 self.report_with_use_injections(krate);
4901 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4902 let msg = "macro-expanded `macro_export` macros from the current crate \
4903 cannot be referred to by absolute paths";
4904 self.session.buffer_lint_with_diagnostic(
4905 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4906 CRATE_NODE_ID, span_use, msg,
4907 lint::builtin::BuiltinLintDiagnostics::
4908 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4912 for ambiguity_error in &self.ambiguity_errors {
4913 self.report_ambiguity_error(ambiguity_error);
4916 let mut reported_spans = FxHashSet::default();
4917 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
4918 if reported_spans.insert(dedup_span) {
4919 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
4920 binding.descr(), ident.name);
4925 fn report_with_use_injections(&mut self, krate: &Crate) {
4926 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4927 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4928 if !candidates.is_empty() {
4929 show_candidates(&mut err, span, &candidates, better, found_use);
4935 fn report_conflict<'b>(&mut self,
4939 new_binding: &NameBinding<'b>,
4940 old_binding: &NameBinding<'b>) {
4941 // Error on the second of two conflicting names
4942 if old_binding.span.lo() > new_binding.span.lo() {
4943 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4946 let container = match parent.kind {
4947 ModuleKind::Def(Def::Mod(_), _) => "module",
4948 ModuleKind::Def(Def::Trait(_), _) => "trait",
4949 ModuleKind::Block(..) => "block",
4953 let old_noun = match old_binding.is_import() {
4955 false => "definition",
4958 let new_participle = match new_binding.is_import() {
4963 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4965 if let Some(s) = self.name_already_seen.get(&name) {
4971 let old_kind = match (ns, old_binding.module()) {
4972 (ValueNS, _) => "value",
4973 (MacroNS, _) => "macro",
4974 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4975 (TypeNS, Some(module)) if module.is_normal() => "module",
4976 (TypeNS, Some(module)) if module.is_trait() => "trait",
4977 (TypeNS, _) => "type",
4980 let msg = format!("the name `{}` is defined multiple times", name);
4982 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4983 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4984 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4985 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4986 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4988 _ => match (old_binding.is_import(), new_binding.is_import()) {
4989 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4990 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4991 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4995 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5000 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5001 if !old_binding.span.is_dummy() {
5002 err.span_label(self.session.source_map().def_span(old_binding.span),
5003 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
5006 // See https://github.com/rust-lang/rust/issues/32354
5007 if old_binding.is_import() || new_binding.is_import() {
5008 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
5014 let cm = self.session.source_map();
5015 let rename_msg = "you can use `as` to change the binding name of the import";
5019 NameBindingKind::Import { directive, ..},
5022 cm.span_to_snippet(binding.span),
5023 binding.kind.clone(),
5024 binding.span.is_dummy(),
5026 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5027 format!("Other{}", name)
5029 format!("other_{}", name)
5032 err.span_suggestion_with_applicability(
5035 match directive.subclass {
5036 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5037 format!("self as {}", suggested_name),
5038 ImportDirectiveSubclass::SingleImport { source, .. } =>
5041 &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
5043 if snippet.ends_with(";") {
5049 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5051 "extern crate {} as {};",
5052 source.unwrap_or(target.name),
5055 _ => unreachable!(),
5057 Applicability::MaybeIncorrect,
5060 err.span_label(binding.span, rename_msg);
5065 self.name_already_seen.insert(name, span);
5068 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5069 -> Option<&'a NameBinding<'a>> {
5070 if ident.is_path_segment_keyword() {
5071 // Make sure `self`, `super` etc produce an error when passed to here.
5074 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5075 if let Some(binding) = entry.extern_crate_item {
5078 let crate_id = if !speculative {
5079 self.crate_loader.process_path_extern(ident.name, ident.span)
5080 } else if let Some(crate_id) =
5081 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5086 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5087 self.populate_module_if_necessary(&crate_root);
5088 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5089 .to_name_binding(self.arenas))
5095 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5096 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5099 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5100 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5103 fn names_to_string(idents: &[Ident]) -> String {
5104 let mut result = String::new();
5105 for (i, ident) in idents.iter()
5106 .filter(|ident| ident.name != keywords::PathRoot.name())
5109 result.push_str("::");
5111 result.push_str(&ident.as_str());
5116 fn path_names_to_string(path: &Path) -> String {
5117 names_to_string(&path.segments.iter()
5118 .map(|seg| seg.ident)
5119 .collect::<Vec<_>>())
5122 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
5123 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
5124 let variant_path = &suggestion.path;
5125 let variant_path_string = path_names_to_string(variant_path);
5127 let path_len = suggestion.path.segments.len();
5128 let enum_path = ast::Path {
5129 span: suggestion.path.span,
5130 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5132 let enum_path_string = path_names_to_string(&enum_path);
5134 (suggestion.path.span, variant_path_string, enum_path_string)
5138 /// When an entity with a given name is not available in scope, we search for
5139 /// entities with that name in all crates. This method allows outputting the
5140 /// results of this search in a programmer-friendly way
5141 fn show_candidates(err: &mut DiagnosticBuilder,
5142 // This is `None` if all placement locations are inside expansions
5144 candidates: &[ImportSuggestion],
5148 // we want consistent results across executions, but candidates are produced
5149 // by iterating through a hash map, so make sure they are ordered:
5150 let mut path_strings: Vec<_> =
5151 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5152 path_strings.sort();
5154 let better = if better { "better " } else { "" };
5155 let msg_diff = match path_strings.len() {
5156 1 => " is found in another module, you can import it",
5157 _ => "s are found in other modules, you can import them",
5159 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5161 if let Some(span) = span {
5162 for candidate in &mut path_strings {
5163 // produce an additional newline to separate the new use statement
5164 // from the directly following item.
5165 let additional_newline = if found_use {
5170 *candidate = format!("use {};\n{}", candidate, additional_newline);
5173 err.span_suggestions_with_applicability(
5176 path_strings.into_iter(),
5177 Applicability::Unspecified,
5182 for candidate in path_strings {
5184 msg.push_str(&candidate);
5189 /// A somewhat inefficient routine to obtain the name of a module.
5190 fn module_to_string(module: Module) -> Option<String> {
5191 let mut names = Vec::new();
5193 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
5194 if let ModuleKind::Def(_, name) = module.kind {
5195 if let Some(parent) = module.parent {
5196 names.push(Ident::with_empty_ctxt(name));
5197 collect_mod(names, parent);
5200 // danger, shouldn't be ident?
5201 names.push(Ident::from_str("<opaque>"));
5202 collect_mod(names, module.parent.unwrap());
5205 collect_mod(&mut names, module);
5207 if names.is_empty() {
5210 Some(names_to_string(&names.into_iter()
5212 .collect::<Vec<_>>()))
5215 fn err_path_resolution() -> PathResolution {
5216 PathResolution::new(Def::Err)
5219 #[derive(PartialEq,Copy, Clone)]
5220 pub enum MakeGlobMap {
5225 #[derive(Copy, Clone, Debug)]
5227 /// Do not issue the lint
5230 /// This lint applies to some random path like `impl ::foo::Bar`
5231 /// or whatever. In this case, we can take the span of that path.
5234 /// This lint comes from a `use` statement. In this case, what we
5235 /// care about really is the *root* `use` statement; e.g., if we
5236 /// have nested things like `use a::{b, c}`, we care about the
5238 UsePath { root_id: NodeId, root_span: Span },
5240 /// This is the "trait item" from a fully qualified path. For example,
5241 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5242 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5243 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5247 fn node_id(&self) -> Option<NodeId> {
5249 CrateLint::No => None,
5250 CrateLint::SimplePath(id) |
5251 CrateLint::UsePath { root_id: id, .. } |
5252 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5257 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }