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 #![cfg_attr(not(stage0), feature(nll))]
17 #![cfg_attr(not(stage0), feature(infer_outlives_requirements))]
18 #![feature(rustc_diagnostic_macros)]
19 #![feature(slice_sort_by_cached_key)]
25 extern crate syntax_pos;
26 extern crate rustc_errors as errors;
30 extern crate rustc_data_structures;
31 extern crate rustc_metadata;
33 pub use rustc::hir::def::{Namespace, PerNS};
35 use self::TypeParameters::*;
38 use rustc::hir::map::{Definitions, DefCollector};
39 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
40 use rustc::middle::cstore::CrateStore;
41 use rustc::session::Session;
43 use rustc::hir::def::*;
44 use rustc::hir::def::Namespace::*;
45 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
47 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
48 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
50 use rustc_metadata::creader::CrateLoader;
51 use rustc_metadata::cstore::CStore;
53 use syntax::source_map::SourceMap;
54 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
55 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
56 use syntax::ext::base::SyntaxExtension;
57 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
58 use syntax::ext::base::MacroKind;
59 use syntax::symbol::{Symbol, keywords};
60 use syntax::util::lev_distance::find_best_match_for_name;
62 use syntax::visit::{self, FnKind, Visitor};
64 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
65 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
66 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
67 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
68 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
69 use syntax::feature_gate::{feature_err, GateIssue};
72 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
73 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
75 use std::cell::{Cell, RefCell};
77 use std::collections::BTreeSet;
80 use std::mem::replace;
81 use rustc_data_structures::sync::Lrc;
83 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
84 use macros::{InvocationData, LegacyBinding};
86 // NB: This module needs to be declared first so diagnostics are
87 // registered before they are used.
92 mod build_reduced_graph;
95 fn is_known_tool(name: Name) -> bool {
96 ["clippy", "rustfmt"].contains(&&*name.as_str())
99 /// A free importable items suggested in case of resolution failure.
100 struct ImportSuggestion {
104 /// A field or associated item from self type suggested in case of resolution failure.
105 enum AssocSuggestion {
112 struct BindingError {
114 origin: BTreeSet<Span>,
115 target: BTreeSet<Span>,
118 impl PartialOrd for BindingError {
119 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
120 Some(self.cmp(other))
124 impl PartialEq for BindingError {
125 fn eq(&self, other: &BindingError) -> bool {
126 self.name == other.name
130 impl Ord for BindingError {
131 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
132 self.name.cmp(&other.name)
136 enum ResolutionError<'a> {
137 /// error E0401: can't use type parameters from outer function
138 TypeParametersFromOuterFunction(Def),
139 /// error E0403: the name is already used for a type parameter in this type parameter list
140 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
141 /// error E0407: method is not a member of trait
142 MethodNotMemberOfTrait(Name, &'a str),
143 /// error E0437: type is not a member of trait
144 TypeNotMemberOfTrait(Name, &'a str),
145 /// error E0438: const is not a member of trait
146 ConstNotMemberOfTrait(Name, &'a str),
147 /// error E0408: variable `{}` is not bound in all patterns
148 VariableNotBoundInPattern(&'a BindingError),
149 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
150 VariableBoundWithDifferentMode(Name, Span),
151 /// error E0415: identifier is bound more than once in this parameter list
152 IdentifierBoundMoreThanOnceInParameterList(&'a str),
153 /// error E0416: identifier is bound more than once in the same pattern
154 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
155 /// error E0426: use of undeclared label
156 UndeclaredLabel(&'a str, Option<Name>),
157 /// error E0429: `self` imports are only allowed within a { } list
158 SelfImportsOnlyAllowedWithin,
159 /// error E0430: `self` import can only appear once in the list
160 SelfImportCanOnlyAppearOnceInTheList,
161 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
162 SelfImportOnlyInImportListWithNonEmptyPrefix,
163 /// error E0432: unresolved import
164 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
165 /// error E0433: failed to resolve
166 FailedToResolve(&'a str),
167 /// error E0434: can't capture dynamic environment in a fn item
168 CannotCaptureDynamicEnvironmentInFnItem,
169 /// error E0435: attempt to use a non-constant value in a constant
170 AttemptToUseNonConstantValueInConstant,
171 /// error E0530: X bindings cannot shadow Ys
172 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
173 /// error E0128: type parameters with a default cannot use forward declared identifiers
174 ForwardDeclaredTyParam,
177 /// Combines an error with provided span and emits it
179 /// This takes the error provided, combines it with the span and any additional spans inside the
180 /// error and emits it.
181 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
183 resolution_error: ResolutionError<'a>) {
184 resolve_struct_error(resolver, span, resolution_error).emit();
187 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
189 resolution_error: ResolutionError<'a>)
190 -> DiagnosticBuilder<'sess> {
191 match resolution_error {
192 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
193 let mut err = struct_span_err!(resolver.session,
196 "can't use type parameters from outer function");
197 err.span_label(span, "use of type variable from outer function");
199 let cm = resolver.session.source_map();
201 Def::SelfTy(_, maybe_impl_defid) => {
202 if let Some(impl_span) = maybe_impl_defid.map_or(None,
203 |def_id| resolver.definitions.opt_span(def_id)) {
204 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
205 "`Self` type implicitly declared here, on the `impl`");
208 Def::TyParam(typaram_defid) => {
209 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
210 err.span_label(typaram_span, "type variable from outer function");
214 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
219 // Try to retrieve the span of the function signature and generate a new message with
220 // a local type parameter
221 let sugg_msg = "try using a local type parameter instead";
222 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
223 // Suggest the modification to the user
224 err.span_suggestion_with_applicability(
228 Applicability::MachineApplicable,
230 } else if let Some(sp) = cm.generate_fn_name_span(span) {
231 err.span_label(sp, "try adding a local type parameter in this method instead");
233 err.help("try using a local type parameter instead");
238 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
239 let mut err = struct_span_err!(resolver.session,
242 "the name `{}` is already used for a type parameter \
243 in this type parameter list",
245 err.span_label(span, "already used");
246 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
249 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
250 let mut err = struct_span_err!(resolver.session,
253 "method `{}` is not a member of trait `{}`",
256 err.span_label(span, format!("not a member of trait `{}`", trait_));
259 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
260 let mut err = struct_span_err!(resolver.session,
263 "type `{}` is not a member of trait `{}`",
266 err.span_label(span, format!("not a member of trait `{}`", trait_));
269 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
270 let mut err = struct_span_err!(resolver.session,
273 "const `{}` is not a member of trait `{}`",
276 err.span_label(span, format!("not a member of trait `{}`", trait_));
279 ResolutionError::VariableNotBoundInPattern(binding_error) => {
280 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
281 let msp = MultiSpan::from_spans(target_sp.clone());
282 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
283 let mut err = resolver.session.struct_span_err_with_code(
286 DiagnosticId::Error("E0408".into()),
288 for sp in target_sp {
289 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
291 let origin_sp = binding_error.origin.iter().cloned();
292 for sp in origin_sp {
293 err.span_label(sp, "variable not in all patterns");
297 ResolutionError::VariableBoundWithDifferentMode(variable_name,
298 first_binding_span) => {
299 let mut err = struct_span_err!(resolver.session,
302 "variable `{}` is bound in inconsistent \
303 ways within the same match arm",
305 err.span_label(span, "bound in different ways");
306 err.span_label(first_binding_span, "first binding");
309 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
310 let mut err = struct_span_err!(resolver.session,
313 "identifier `{}` is bound more than once in this parameter list",
315 err.span_label(span, "used as parameter more than once");
318 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
319 let mut err = struct_span_err!(resolver.session,
322 "identifier `{}` is bound more than once in the same pattern",
324 err.span_label(span, "used in a pattern more than once");
327 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
328 let mut err = struct_span_err!(resolver.session,
331 "use of undeclared label `{}`",
333 if let Some(lev_candidate) = lev_candidate {
334 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
336 err.span_label(span, format!("undeclared label `{}`", name));
340 ResolutionError::SelfImportsOnlyAllowedWithin => {
341 struct_span_err!(resolver.session,
345 "`self` imports are only allowed within a { } list")
347 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
348 let mut err = struct_span_err!(resolver.session, span, E0430,
349 "`self` import can only appear once in an import list");
350 err.span_label(span, "can only appear once in an import list");
353 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
354 let mut err = struct_span_err!(resolver.session, span, E0431,
355 "`self` import can only appear in an import list with \
356 a non-empty prefix");
357 err.span_label(span, "can only appear in an import list with a non-empty prefix");
360 ResolutionError::UnresolvedImport(name) => {
361 let (span, msg) = match name {
362 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
363 None => (span, "unresolved import".to_owned()),
365 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
366 if let Some((_, _, p)) = name {
367 err.span_label(span, p);
371 ResolutionError::FailedToResolve(msg) => {
372 let mut err = struct_span_err!(resolver.session, span, E0433,
373 "failed to resolve. {}", msg);
374 err.span_label(span, msg);
377 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
378 let mut err = struct_span_err!(resolver.session,
382 "can't capture dynamic environment in a fn item");
383 err.help("use the `|| { ... }` closure form instead");
386 ResolutionError::AttemptToUseNonConstantValueInConstant => {
387 let mut err = struct_span_err!(resolver.session, span, E0435,
388 "attempt to use a non-constant value in a constant");
389 err.span_label(span, "non-constant value");
392 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
393 let shadows_what = PathResolution::new(binding.def()).kind_name();
394 let mut err = struct_span_err!(resolver.session,
397 "{}s cannot shadow {}s", what_binding, shadows_what);
398 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
399 let participle = if binding.is_import() { "imported" } else { "defined" };
400 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
401 err.span_label(binding.span, msg);
404 ResolutionError::ForwardDeclaredTyParam => {
405 let mut err = struct_span_err!(resolver.session, span, E0128,
406 "type parameters with a default cannot use \
407 forward declared identifiers");
409 span, "defaulted type parameters cannot be forward declared".to_string());
415 /// Adjust the impl span so that just the `impl` keyword is taken by removing
416 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
417 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
419 /// Attention: The method used is very fragile since it essentially duplicates the work of the
420 /// parser. If you need to use this function or something similar, please consider updating the
421 /// source_map functions and this function to something more robust.
422 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
423 let impl_span = cm.span_until_char(impl_span, '<');
424 let impl_span = cm.span_until_whitespace(impl_span);
428 #[derive(Copy, Clone, Debug)]
431 binding_mode: BindingMode,
434 /// Map from the name in a pattern to its binding mode.
435 type BindingMap = FxHashMap<Ident, BindingInfo>;
437 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
448 fn descr(self) -> &'static str {
450 PatternSource::Match => "match binding",
451 PatternSource::IfLet => "if let binding",
452 PatternSource::WhileLet => "while let binding",
453 PatternSource::Let => "let binding",
454 PatternSource::For => "for binding",
455 PatternSource::FnParam => "function parameter",
460 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
461 enum AliasPossibility {
466 #[derive(Copy, Clone, Debug)]
467 enum PathSource<'a> {
468 // Type paths `Path`.
470 // Trait paths in bounds or impls.
471 Trait(AliasPossibility),
472 // Expression paths `path`, with optional parent context.
473 Expr(Option<&'a Expr>),
474 // Paths in path patterns `Path`.
476 // Paths in struct expressions and patterns `Path { .. }`.
478 // Paths in tuple struct patterns `Path(..)`.
480 // `m::A::B` in `<T as m::A>::B::C`.
481 TraitItem(Namespace),
482 // Path in `pub(path)`
484 // Path in `use a::b::{...};`
488 impl<'a> PathSource<'a> {
489 fn namespace(self) -> Namespace {
491 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
492 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
493 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
494 PathSource::TraitItem(ns) => ns,
498 fn global_by_default(self) -> bool {
500 PathSource::Visibility | PathSource::ImportPrefix => true,
501 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
502 PathSource::Struct | PathSource::TupleStruct |
503 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
507 fn defer_to_typeck(self) -> bool {
509 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
510 PathSource::Struct | PathSource::TupleStruct => true,
511 PathSource::Trait(_) | PathSource::TraitItem(..) |
512 PathSource::Visibility | PathSource::ImportPrefix => false,
516 fn descr_expected(self) -> &'static str {
518 PathSource::Type => "type",
519 PathSource::Trait(_) => "trait",
520 PathSource::Pat => "unit struct/variant or constant",
521 PathSource::Struct => "struct, variant or union type",
522 PathSource::TupleStruct => "tuple struct/variant",
523 PathSource::Visibility => "module",
524 PathSource::ImportPrefix => "module or enum",
525 PathSource::TraitItem(ns) => match ns {
526 TypeNS => "associated type",
527 ValueNS => "method or associated constant",
528 MacroNS => bug!("associated macro"),
530 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
531 // "function" here means "anything callable" rather than `Def::Fn`,
532 // this is not precise but usually more helpful than just "value".
533 Some(&ExprKind::Call(..)) => "function",
539 fn is_expected(self, def: Def) -> bool {
541 PathSource::Type => match def {
542 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
543 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
544 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
545 Def::Existential(..) |
546 Def::ForeignTy(..) => true,
549 PathSource::Trait(AliasPossibility::No) => match def {
550 Def::Trait(..) => true,
553 PathSource::Trait(AliasPossibility::Maybe) => match def {
554 Def::Trait(..) => true,
555 Def::TraitAlias(..) => true,
558 PathSource::Expr(..) => match def {
559 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
560 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
561 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
562 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
565 PathSource::Pat => match def {
566 Def::StructCtor(_, CtorKind::Const) |
567 Def::VariantCtor(_, CtorKind::Const) |
568 Def::Const(..) | Def::AssociatedConst(..) => true,
571 PathSource::TupleStruct => match def {
572 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
575 PathSource::Struct => match def {
576 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
577 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
580 PathSource::TraitItem(ns) => match def {
581 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
582 Def::AssociatedTy(..) if ns == TypeNS => true,
585 PathSource::ImportPrefix => match def {
586 Def::Mod(..) | Def::Enum(..) => true,
589 PathSource::Visibility => match def {
590 Def::Mod(..) => true,
596 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
597 __diagnostic_used!(E0404);
598 __diagnostic_used!(E0405);
599 __diagnostic_used!(E0412);
600 __diagnostic_used!(E0422);
601 __diagnostic_used!(E0423);
602 __diagnostic_used!(E0425);
603 __diagnostic_used!(E0531);
604 __diagnostic_used!(E0532);
605 __diagnostic_used!(E0573);
606 __diagnostic_used!(E0574);
607 __diagnostic_used!(E0575);
608 __diagnostic_used!(E0576);
609 __diagnostic_used!(E0577);
610 __diagnostic_used!(E0578);
611 match (self, has_unexpected_resolution) {
612 (PathSource::Trait(_), true) => "E0404",
613 (PathSource::Trait(_), false) => "E0405",
614 (PathSource::Type, true) => "E0573",
615 (PathSource::Type, false) => "E0412",
616 (PathSource::Struct, true) => "E0574",
617 (PathSource::Struct, false) => "E0422",
618 (PathSource::Expr(..), true) => "E0423",
619 (PathSource::Expr(..), false) => "E0425",
620 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
621 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
622 (PathSource::TraitItem(..), true) => "E0575",
623 (PathSource::TraitItem(..), false) => "E0576",
624 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
625 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
630 struct UsePlacementFinder {
631 target_module: NodeId,
636 impl UsePlacementFinder {
637 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
638 let mut finder = UsePlacementFinder {
643 visit::walk_crate(&mut finder, krate);
644 (finder.span, finder.found_use)
648 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
651 module: &'tcx ast::Mod,
653 _: &[ast::Attribute],
656 if self.span.is_some() {
659 if node_id != self.target_module {
660 visit::walk_mod(self, module);
663 // find a use statement
664 for item in &module.items {
666 ItemKind::Use(..) => {
667 // don't suggest placing a use before the prelude
668 // import or other generated ones
669 if item.span.ctxt().outer().expn_info().is_none() {
670 self.span = Some(item.span.shrink_to_lo());
671 self.found_use = true;
675 // don't place use before extern crate
676 ItemKind::ExternCrate(_) => {}
677 // but place them before the first other item
678 _ => if self.span.map_or(true, |span| item.span < span ) {
679 if item.span.ctxt().outer().expn_info().is_none() {
680 // don't insert between attributes and an item
681 if item.attrs.is_empty() {
682 self.span = Some(item.span.shrink_to_lo());
684 // find the first attribute on the item
685 for attr in &item.attrs {
686 if self.span.map_or(true, |span| attr.span < span) {
687 self.span = Some(attr.span.shrink_to_lo());
698 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
699 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
700 fn visit_item(&mut self, item: &'tcx Item) {
701 self.resolve_item(item);
703 fn visit_arm(&mut self, arm: &'tcx Arm) {
704 self.resolve_arm(arm);
706 fn visit_block(&mut self, block: &'tcx Block) {
707 self.resolve_block(block);
709 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
710 self.with_constant_rib(|this| {
711 visit::walk_anon_const(this, constant);
714 fn visit_expr(&mut self, expr: &'tcx Expr) {
715 self.resolve_expr(expr, None);
717 fn visit_local(&mut self, local: &'tcx Local) {
718 self.resolve_local(local);
720 fn visit_ty(&mut self, ty: &'tcx Ty) {
722 TyKind::Path(ref qself, ref path) => {
723 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
725 TyKind::ImplicitSelf => {
726 let self_ty = keywords::SelfType.ident();
727 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
728 .map_or(Def::Err, |d| d.def());
729 self.record_def(ty.id, PathResolution::new(def));
733 visit::walk_ty(self, ty);
735 fn visit_poly_trait_ref(&mut self,
736 tref: &'tcx ast::PolyTraitRef,
737 m: &'tcx ast::TraitBoundModifier) {
738 self.smart_resolve_path(tref.trait_ref.ref_id, None,
739 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
740 visit::walk_poly_trait_ref(self, tref, m);
742 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
743 let type_parameters = match foreign_item.node {
744 ForeignItemKind::Fn(_, ref generics) => {
745 HasTypeParameters(generics, ItemRibKind)
747 ForeignItemKind::Static(..) => NoTypeParameters,
748 ForeignItemKind::Ty => NoTypeParameters,
749 ForeignItemKind::Macro(..) => NoTypeParameters,
751 self.with_type_parameter_rib(type_parameters, |this| {
752 visit::walk_foreign_item(this, foreign_item);
755 fn visit_fn(&mut self,
756 function_kind: FnKind<'tcx>,
757 declaration: &'tcx FnDecl,
761 let (rib_kind, asyncness) = match function_kind {
762 FnKind::ItemFn(_, ref header, ..) =>
763 (ItemRibKind, header.asyncness),
764 FnKind::Method(_, ref sig, _, _) =>
765 (TraitOrImplItemRibKind, sig.header.asyncness),
766 FnKind::Closure(_) =>
767 // Async closures aren't resolved through `visit_fn`-- they're
768 // processed separately
769 (ClosureRibKind(node_id), IsAsync::NotAsync),
772 // Create a value rib for the function.
773 self.ribs[ValueNS].push(Rib::new(rib_kind));
775 // Create a label rib for the function.
776 self.label_ribs.push(Rib::new(rib_kind));
778 // Add each argument to the rib.
779 let mut bindings_list = FxHashMap();
780 for argument in &declaration.inputs {
781 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
783 self.visit_ty(&argument.ty);
785 debug!("(resolving function) recorded argument");
787 visit::walk_fn_ret_ty(self, &declaration.output);
789 // Resolve the function body, potentially inside the body of an async closure
790 if let IsAsync::Async { closure_id, .. } = asyncness {
791 let rib_kind = ClosureRibKind(closure_id);
792 self.ribs[ValueNS].push(Rib::new(rib_kind));
793 self.label_ribs.push(Rib::new(rib_kind));
796 match function_kind {
797 FnKind::ItemFn(.., body) |
798 FnKind::Method(.., body) => {
799 self.visit_block(body);
801 FnKind::Closure(body) => {
802 self.visit_expr(body);
806 // Leave the body of the async closure
807 if asyncness.is_async() {
808 self.label_ribs.pop();
809 self.ribs[ValueNS].pop();
812 debug!("(resolving function) leaving function");
814 self.label_ribs.pop();
815 self.ribs[ValueNS].pop();
817 fn visit_generics(&mut self, generics: &'tcx Generics) {
818 // For type parameter defaults, we have to ban access
819 // to following type parameters, as the Substs can only
820 // provide previous type parameters as they're built. We
821 // put all the parameters on the ban list and then remove
822 // them one by one as they are processed and become available.
823 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
824 let mut found_default = false;
825 default_ban_rib.bindings.extend(generics.params.iter()
826 .filter_map(|param| match param.kind {
827 GenericParamKind::Lifetime { .. } => None,
828 GenericParamKind::Type { ref default, .. } => {
829 found_default |= default.is_some();
831 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
838 for param in &generics.params {
840 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
841 GenericParamKind::Type { ref default, .. } => {
842 for bound in ¶m.bounds {
843 self.visit_param_bound(bound);
846 if let Some(ref ty) = default {
847 self.ribs[TypeNS].push(default_ban_rib);
849 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
852 // Allow all following defaults to refer to this type parameter.
853 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
857 for p in &generics.where_clause.predicates {
858 self.visit_where_predicate(p);
863 #[derive(Copy, Clone)]
864 enum TypeParameters<'a, 'b> {
866 HasTypeParameters(// Type parameters.
869 // The kind of the rib used for type parameters.
873 /// The rib kind controls the translation of local
874 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
875 #[derive(Copy, Clone, Debug)]
877 /// No translation needs to be applied.
880 /// We passed through a closure scope at the given node ID.
881 /// Translate upvars as appropriate.
882 ClosureRibKind(NodeId /* func id */),
884 /// We passed through an impl or trait and are now in one of its
885 /// methods or associated types. Allow references to ty params that impl or trait
886 /// binds. Disallow any other upvars (including other ty params that are
888 TraitOrImplItemRibKind,
890 /// We passed through an item scope. Disallow upvars.
893 /// We're in a constant item. Can't refer to dynamic stuff.
896 /// We passed through a module.
897 ModuleRibKind(Module<'a>),
899 /// We passed through a `macro_rules!` statement
900 MacroDefinition(DefId),
902 /// All bindings in this rib are type parameters that can't be used
903 /// from the default of a type parameter because they're not declared
904 /// before said type parameter. Also see the `visit_generics` override.
905 ForwardTyParamBanRibKind,
910 /// A rib represents a scope names can live in. Note that these appear in many places, not just
911 /// around braces. At any place where the list of accessible names (of the given namespace)
912 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
913 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
916 /// Different [rib kinds](enum.RibKind) are transparent for different names.
918 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
919 /// resolving, the name is looked up from inside out.
922 bindings: FxHashMap<Ident, Def>,
927 fn new(kind: RibKind<'a>) -> Rib<'a> {
929 bindings: FxHashMap(),
935 /// An intermediate resolution result.
937 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
938 /// items are visible in their whole block, while defs only from the place they are defined
940 enum LexicalScopeBinding<'a> {
941 Item(&'a NameBinding<'a>),
945 impl<'a> LexicalScopeBinding<'a> {
946 fn item(self) -> Option<&'a NameBinding<'a>> {
948 LexicalScopeBinding::Item(binding) => Some(binding),
953 fn def(self) -> Def {
955 LexicalScopeBinding::Item(binding) => binding.def(),
956 LexicalScopeBinding::Def(def) => def,
961 #[derive(Copy, Clone, Debug)]
962 pub enum ModuleOrUniformRoot<'a> {
966 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
967 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
968 /// but *not* `extern`), in the Rust 2018 edition.
972 #[derive(Clone, Debug)]
973 enum PathResult<'a> {
974 Module(ModuleOrUniformRoot<'a>),
975 NonModule(PathResolution),
977 Failed(Span, String, bool /* is the error from the last segment? */),
981 /// An anonymous module, eg. just a block.
986 /// { // This is an anonymous module
987 /// f(); // This resolves to (2) as we are inside the block.
990 /// f(); // Resolves to (1)
994 /// Any module with a name.
998 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
999 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1004 /// One node in the tree of modules.
1005 pub struct ModuleData<'a> {
1006 parent: Option<Module<'a>>,
1009 // The def id of the closest normal module (`mod`) ancestor (including this module).
1010 normal_ancestor_id: DefId,
1012 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1013 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, MacroKind, Option<Def>)>>,
1014 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1016 // Macro invocations that can expand into items in this module.
1017 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1019 no_implicit_prelude: bool,
1021 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1022 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1024 // Used to memoize the traits in this module for faster searches through all traits in scope.
1025 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1027 // Whether this module is populated. If not populated, any attempt to
1028 // access the children must be preceded with a
1029 // `populate_module_if_necessary` call.
1030 populated: Cell<bool>,
1032 /// Span of the module itself. Used for error reporting.
1038 type Module<'a> = &'a ModuleData<'a>;
1040 impl<'a> ModuleData<'a> {
1041 fn new(parent: Option<Module<'a>>,
1043 normal_ancestor_id: DefId,
1045 span: Span) -> Self {
1050 resolutions: RefCell::new(FxHashMap()),
1051 legacy_macro_resolutions: RefCell::new(Vec::new()),
1052 macro_resolutions: RefCell::new(Vec::new()),
1053 unresolved_invocations: RefCell::new(FxHashSet()),
1054 no_implicit_prelude: false,
1055 glob_importers: RefCell::new(Vec::new()),
1056 globs: RefCell::new(Vec::new()),
1057 traits: RefCell::new(None),
1058 populated: Cell::new(normal_ancestor_id.is_local()),
1064 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1065 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1066 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1070 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1071 let resolutions = self.resolutions.borrow();
1072 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1073 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1074 for &(&(ident, ns), &resolution) in resolutions.iter() {
1075 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1079 fn def(&self) -> Option<Def> {
1081 ModuleKind::Def(def, _) => Some(def),
1086 fn def_id(&self) -> Option<DefId> {
1087 self.def().as_ref().map(Def::def_id)
1090 // `self` resolves to the first module ancestor that `is_normal`.
1091 fn is_normal(&self) -> bool {
1093 ModuleKind::Def(Def::Mod(_), _) => true,
1098 fn is_trait(&self) -> bool {
1100 ModuleKind::Def(Def::Trait(_), _) => true,
1105 fn is_local(&self) -> bool {
1106 self.normal_ancestor_id.is_local()
1109 fn nearest_item_scope(&'a self) -> Module<'a> {
1110 if self.is_trait() { self.parent.unwrap() } else { self }
1114 impl<'a> fmt::Debug for ModuleData<'a> {
1115 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1116 write!(f, "{:?}", self.def())
1120 /// Records a possibly-private value, type, or module definition.
1121 #[derive(Clone, Debug)]
1122 pub struct NameBinding<'a> {
1123 kind: NameBindingKind<'a>,
1126 vis: ty::Visibility,
1129 pub trait ToNameBinding<'a> {
1130 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1133 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1134 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1139 #[derive(Clone, Debug)]
1140 enum NameBindingKind<'a> {
1141 Def(Def, /* is_macro_export */ bool),
1144 binding: &'a NameBinding<'a>,
1145 directive: &'a ImportDirective<'a>,
1149 b1: &'a NameBinding<'a>,
1150 b2: &'a NameBinding<'a>,
1154 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1156 struct UseError<'a> {
1157 err: DiagnosticBuilder<'a>,
1158 /// Attach `use` statements for these candidates
1159 candidates: Vec<ImportSuggestion>,
1160 /// The node id of the module to place the use statements in
1162 /// Whether the diagnostic should state that it's "better"
1166 struct AmbiguityError<'a> {
1170 b1: &'a NameBinding<'a>,
1171 b2: &'a NameBinding<'a>,
1174 impl<'a> NameBinding<'a> {
1175 fn module(&self) -> Option<Module<'a>> {
1177 NameBindingKind::Module(module) => Some(module),
1178 NameBindingKind::Import { binding, .. } => binding.module(),
1183 fn def(&self) -> Def {
1185 NameBindingKind::Def(def, _) => def,
1186 NameBindingKind::Module(module) => module.def().unwrap(),
1187 NameBindingKind::Import { binding, .. } => binding.def(),
1188 NameBindingKind::Ambiguity { .. } => Def::Err,
1192 fn def_ignoring_ambiguity(&self) -> Def {
1194 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1195 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1200 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1201 resolver.get_macro(self.def_ignoring_ambiguity())
1204 // We sometimes need to treat variants as `pub` for backwards compatibility
1205 fn pseudo_vis(&self) -> ty::Visibility {
1206 if self.is_variant() && self.def().def_id().is_local() {
1207 ty::Visibility::Public
1213 fn is_variant(&self) -> bool {
1215 NameBindingKind::Def(Def::Variant(..), _) |
1216 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1221 fn is_extern_crate(&self) -> bool {
1223 NameBindingKind::Import {
1224 directive: &ImportDirective {
1225 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1232 fn is_import(&self) -> bool {
1234 NameBindingKind::Import { .. } => true,
1239 fn is_renamed_extern_crate(&self) -> bool {
1240 if let NameBindingKind::Import { directive, ..} = self.kind {
1241 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1248 fn is_glob_import(&self) -> bool {
1250 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1251 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1256 fn is_importable(&self) -> bool {
1258 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1263 fn is_macro_def(&self) -> bool {
1265 NameBindingKind::Def(Def::Macro(..), _) => true,
1270 fn descr(&self) -> &'static str {
1271 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1275 /// Interns the names of the primitive types.
1277 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1278 /// special handling, since they have no place of origin.
1279 struct PrimitiveTypeTable {
1280 primitive_types: FxHashMap<Name, PrimTy>,
1283 impl PrimitiveTypeTable {
1284 fn new() -> PrimitiveTypeTable {
1285 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1287 table.intern("bool", Bool);
1288 table.intern("char", Char);
1289 table.intern("f32", Float(FloatTy::F32));
1290 table.intern("f64", Float(FloatTy::F64));
1291 table.intern("isize", Int(IntTy::Isize));
1292 table.intern("i8", Int(IntTy::I8));
1293 table.intern("i16", Int(IntTy::I16));
1294 table.intern("i32", Int(IntTy::I32));
1295 table.intern("i64", Int(IntTy::I64));
1296 table.intern("i128", Int(IntTy::I128));
1297 table.intern("str", Str);
1298 table.intern("usize", Uint(UintTy::Usize));
1299 table.intern("u8", Uint(UintTy::U8));
1300 table.intern("u16", Uint(UintTy::U16));
1301 table.intern("u32", Uint(UintTy::U32));
1302 table.intern("u64", Uint(UintTy::U64));
1303 table.intern("u128", Uint(UintTy::U128));
1307 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1308 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1312 /// The main resolver class.
1314 /// This is the visitor that walks the whole crate.
1315 pub struct Resolver<'a, 'b: 'a> {
1316 session: &'a Session,
1319 pub definitions: Definitions,
1321 graph_root: Module<'a>,
1323 prelude: Option<Module<'a>>,
1324 extern_prelude: FxHashSet<Name>,
1326 /// n.b. This is used only for better diagnostics, not name resolution itself.
1327 has_self: FxHashSet<DefId>,
1329 /// Names of fields of an item `DefId` accessible with dot syntax.
1330 /// Used for hints during error reporting.
1331 field_names: FxHashMap<DefId, Vec<Name>>,
1333 /// All imports known to succeed or fail.
1334 determined_imports: Vec<&'a ImportDirective<'a>>,
1336 /// All non-determined imports.
1337 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1339 /// The module that represents the current item scope.
1340 current_module: Module<'a>,
1342 /// The current set of local scopes for types and values.
1343 /// FIXME #4948: Reuse ribs to avoid allocation.
1344 ribs: PerNS<Vec<Rib<'a>>>,
1346 /// The current set of local scopes, for labels.
1347 label_ribs: Vec<Rib<'a>>,
1349 /// The trait that the current context can refer to.
1350 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1352 /// The current self type if inside an impl (used for better errors).
1353 current_self_type: Option<Ty>,
1355 /// The idents for the primitive types.
1356 primitive_type_table: PrimitiveTypeTable,
1359 import_map: ImportMap,
1360 pub freevars: FreevarMap,
1361 freevars_seen: NodeMap<NodeMap<usize>>,
1362 pub export_map: ExportMap,
1363 pub trait_map: TraitMap,
1365 /// A map from nodes to anonymous modules.
1366 /// Anonymous modules are pseudo-modules that are implicitly created around items
1367 /// contained within blocks.
1369 /// For example, if we have this:
1377 /// There will be an anonymous module created around `g` with the ID of the
1378 /// entry block for `f`.
1379 block_map: NodeMap<Module<'a>>,
1380 module_map: FxHashMap<DefId, Module<'a>>,
1381 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1383 pub make_glob_map: bool,
1384 /// Maps imports to the names of items actually imported (this actually maps
1385 /// all imports, but only glob imports are actually interesting).
1386 pub glob_map: GlobMap,
1388 used_imports: FxHashSet<(NodeId, Namespace)>,
1389 pub maybe_unused_trait_imports: NodeSet,
1390 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1392 /// A list of labels as of yet unused. Labels will be removed from this map when
1393 /// they are used (in a `break` or `continue` statement)
1394 pub unused_labels: FxHashMap<NodeId, Span>,
1396 /// privacy errors are delayed until the end in order to deduplicate them
1397 privacy_errors: Vec<PrivacyError<'a>>,
1398 /// ambiguity errors are delayed for deduplication
1399 ambiguity_errors: Vec<AmbiguityError<'a>>,
1400 /// `use` injections are delayed for better placement and deduplication
1401 use_injections: Vec<UseError<'a>>,
1402 /// `use` injections for proc macros wrongly imported with #[macro_use]
1403 proc_mac_errors: Vec<macros::ProcMacError>,
1404 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1405 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1406 /// macro-expanded `macro_rules` shadowing existing macros
1407 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1409 arenas: &'a ResolverArenas<'a>,
1410 dummy_binding: &'a NameBinding<'a>,
1412 crate_loader: &'a mut CrateLoader<'b>,
1413 macro_names: FxHashSet<Ident>,
1414 macro_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1415 pub all_macros: FxHashMap<Name, Def>,
1416 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1417 macro_defs: FxHashMap<Mark, DefId>,
1418 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1419 pub whitelisted_legacy_custom_derives: Vec<Name>,
1420 pub found_unresolved_macro: bool,
1422 /// List of crate local macros that we need to warn about as being unused.
1423 /// Right now this only includes macro_rules! macros, and macros 2.0.
1424 unused_macros: FxHashSet<DefId>,
1426 /// Maps the `Mark` of an expansion to its containing module or block.
1427 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1429 /// Avoid duplicated errors for "name already defined".
1430 name_already_seen: FxHashMap<Name, Span>,
1432 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1433 warned_proc_macros: FxHashSet<Name>,
1435 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1437 /// This table maps struct IDs into struct constructor IDs,
1438 /// it's not used during normal resolution, only for better error reporting.
1439 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1441 /// Only used for better errors on `fn(): fn()`
1442 current_type_ascription: Vec<Span>,
1444 injected_crate: Option<Module<'a>>,
1446 /// Only supposed to be used by rustdoc, otherwise should be false.
1447 pub ignore_extern_prelude_feature: bool,
1450 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1451 pub struct ResolverArenas<'a> {
1452 modules: arena::TypedArena<ModuleData<'a>>,
1453 local_modules: RefCell<Vec<Module<'a>>>,
1454 name_bindings: arena::TypedArena<NameBinding<'a>>,
1455 import_directives: arena::TypedArena<ImportDirective<'a>>,
1456 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1457 invocation_data: arena::TypedArena<InvocationData<'a>>,
1458 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1461 impl<'a> ResolverArenas<'a> {
1462 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1463 let module = self.modules.alloc(module);
1464 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1465 self.local_modules.borrow_mut().push(module);
1469 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1470 self.local_modules.borrow()
1472 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1473 self.name_bindings.alloc(name_binding)
1475 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1476 -> &'a ImportDirective {
1477 self.import_directives.alloc(import_directive)
1479 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1480 self.name_resolutions.alloc(Default::default())
1482 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1483 -> &'a InvocationData<'a> {
1484 self.invocation_data.alloc(expansion_data)
1486 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1487 self.legacy_bindings.alloc(binding)
1491 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1492 fn parent(self, id: DefId) -> Option<DefId> {
1494 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1495 _ => self.cstore.def_key(id).parent,
1496 }.map(|index| DefId { index, ..id })
1500 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1501 /// the resolver is no longer needed as all the relevant information is inline.
1502 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1503 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1504 self.resolve_hir_path_cb(path, is_value,
1505 |resolver, span, error| resolve_error(resolver, span, error))
1508 fn resolve_str_path(
1511 crate_root: Option<&str>,
1512 components: &[&str],
1513 args: Option<P<hir::GenericArgs>>,
1516 let mut segments = iter::once(keywords::CrateRoot.ident())
1518 crate_root.into_iter()
1519 .chain(components.iter().cloned())
1520 .map(Ident::from_str)
1521 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1523 if let Some(args) = args {
1524 let ident = segments.last().unwrap().ident;
1525 *segments.last_mut().unwrap() = hir::PathSegment {
1532 let mut path = hir::Path {
1535 segments: segments.into(),
1538 self.resolve_hir_path(&mut path, is_value);
1542 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1543 self.def_map.get(&id).cloned()
1546 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1547 self.import_map.get(&id).cloned().unwrap_or_default()
1550 fn definitions(&mut self) -> &mut Definitions {
1551 &mut self.definitions
1555 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1556 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1557 /// isn't something that can be returned because it can't be made to live that long,
1558 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1559 /// just that an error occurred.
1560 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1561 -> Result<hir::Path, ()> {
1563 let mut errored = false;
1565 let mut path = if path_str.starts_with("::") {
1569 segments: iter::once(keywords::CrateRoot.ident()).chain({
1570 path_str.split("::").skip(1).map(Ident::from_str)
1571 }).map(hir::PathSegment::from_ident).collect(),
1577 segments: path_str.split("::").map(Ident::from_str)
1578 .map(hir::PathSegment::from_ident).collect(),
1581 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1582 if errored || path.def == Def::Err {
1589 /// resolve_hir_path, but takes a callback in case there was an error
1590 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1591 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1593 let namespace = if is_value { ValueNS } else { TypeNS };
1594 let hir::Path { ref segments, span, ref mut def } = *path;
1595 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1596 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1597 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1598 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1599 *def = module.def().unwrap(),
1600 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1601 *def = path_res.base_def(),
1602 PathResult::NonModule(..) => match self.resolve_path(
1610 PathResult::Failed(span, msg, _) => {
1611 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1615 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1616 PathResult::Indeterminate => unreachable!(),
1617 PathResult::Failed(span, msg, _) => {
1618 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1624 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1625 pub fn new(session: &'a Session,
1629 make_glob_map: MakeGlobMap,
1630 crate_loader: &'a mut CrateLoader<'crateloader>,
1631 arenas: &'a ResolverArenas<'a>)
1632 -> Resolver<'a, 'crateloader> {
1633 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1634 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1635 let graph_root = arenas.alloc_module(ModuleData {
1636 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1637 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1639 let mut module_map = FxHashMap();
1640 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1642 let mut definitions = Definitions::new();
1643 DefCollector::new(&mut definitions, Mark::root())
1644 .collect_root(crate_name, session.local_crate_disambiguator());
1646 let mut extern_prelude: FxHashSet<Name> =
1647 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1648 if !attr::contains_name(&krate.attrs, "no_core") {
1649 if !attr::contains_name(&krate.attrs, "no_std") {
1650 extern_prelude.insert(Symbol::intern("std"));
1652 extern_prelude.insert(Symbol::intern("core"));
1656 let mut invocations = FxHashMap();
1657 invocations.insert(Mark::root(),
1658 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1660 let mut macro_defs = FxHashMap();
1661 macro_defs.insert(Mark::root(), root_def_id);
1670 // The outermost module has def ID 0; this is not reflected in the
1676 has_self: FxHashSet(),
1677 field_names: FxHashMap(),
1679 determined_imports: Vec::new(),
1680 indeterminate_imports: Vec::new(),
1682 current_module: graph_root,
1684 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1685 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1686 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1688 label_ribs: Vec::new(),
1690 current_trait_ref: None,
1691 current_self_type: None,
1693 primitive_type_table: PrimitiveTypeTable::new(),
1696 import_map: NodeMap(),
1697 freevars: NodeMap(),
1698 freevars_seen: NodeMap(),
1699 export_map: FxHashMap(),
1700 trait_map: NodeMap(),
1702 block_map: NodeMap(),
1703 extern_module_map: FxHashMap(),
1705 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1706 glob_map: NodeMap(),
1708 used_imports: FxHashSet(),
1709 maybe_unused_trait_imports: NodeSet(),
1710 maybe_unused_extern_crates: Vec::new(),
1712 unused_labels: FxHashMap(),
1714 privacy_errors: Vec::new(),
1715 ambiguity_errors: Vec::new(),
1716 use_injections: Vec::new(),
1717 proc_mac_errors: Vec::new(),
1718 disallowed_shadowing: Vec::new(),
1719 macro_expanded_macro_export_errors: BTreeSet::new(),
1722 dummy_binding: arenas.alloc_name_binding(NameBinding {
1723 kind: NameBindingKind::Def(Def::Err, false),
1724 expansion: Mark::root(),
1726 vis: ty::Visibility::Public,
1730 macro_names: FxHashSet(),
1731 macro_prelude: FxHashMap(),
1732 all_macros: FxHashMap(),
1733 macro_map: FxHashMap(),
1736 local_macro_def_scopes: FxHashMap(),
1737 name_already_seen: FxHashMap(),
1738 whitelisted_legacy_custom_derives: Vec::new(),
1739 warned_proc_macros: FxHashSet(),
1740 potentially_unused_imports: Vec::new(),
1741 struct_constructors: DefIdMap(),
1742 found_unresolved_macro: false,
1743 unused_macros: FxHashSet(),
1744 current_type_ascription: Vec::new(),
1745 injected_crate: None,
1746 ignore_extern_prelude_feature: false,
1750 pub fn arenas() -> ResolverArenas<'a> {
1752 modules: arena::TypedArena::new(),
1753 local_modules: RefCell::new(Vec::new()),
1754 name_bindings: arena::TypedArena::new(),
1755 import_directives: arena::TypedArena::new(),
1756 name_resolutions: arena::TypedArena::new(),
1757 invocation_data: arena::TypedArena::new(),
1758 legacy_bindings: arena::TypedArena::new(),
1762 /// Runs the function on each namespace.
1763 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1769 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1771 match self.macro_defs.get(&ctxt.outer()) {
1772 Some(&def_id) => return def_id,
1773 None => ctxt.remove_mark(),
1778 /// Entry point to crate resolution.
1779 pub fn resolve_crate(&mut self, krate: &Crate) {
1780 ImportResolver { resolver: self }.finalize_imports();
1781 self.current_module = self.graph_root;
1782 self.finalize_current_module_macro_resolutions();
1784 visit::walk_crate(self, krate);
1786 check_unused::check_crate(self, krate);
1787 self.report_errors(krate);
1788 self.crate_loader.postprocess(krate);
1795 normal_ancestor_id: DefId,
1799 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1800 self.arenas.alloc_module(module)
1803 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1804 -> bool /* true if an error was reported */ {
1805 match binding.kind {
1806 NameBindingKind::Import { directive, binding, ref used }
1809 directive.used.set(true);
1810 self.used_imports.insert((directive.id, ns));
1811 self.add_to_glob_map(directive.id, ident);
1812 self.record_use(ident, ns, binding, span)
1814 NameBindingKind::Import { .. } => false,
1815 NameBindingKind::Ambiguity { b1, b2 } => {
1816 self.ambiguity_errors.push(AmbiguityError {
1817 span, name: ident.name, lexical: false, b1, b2,
1825 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1826 if self.make_glob_map {
1827 self.glob_map.entry(id).or_default().insert(ident.name);
1831 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1832 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1833 /// `ident` in the first scope that defines it (or None if no scopes define it).
1835 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1836 /// the items are defined in the block. For example,
1839 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1842 /// g(); // This resolves to the local variable `g` since it shadows the item.
1846 /// Invariant: This must only be called during main resolution, not during
1847 /// import resolution.
1848 fn resolve_ident_in_lexical_scope(&mut self,
1851 record_used_id: Option<NodeId>,
1853 -> Option<LexicalScopeBinding<'a>> {
1854 let record_used = record_used_id.is_some();
1855 assert!(ns == TypeNS || ns == ValueNS);
1857 ident.span = if ident.name == keywords::SelfType.name() {
1858 // FIXME(jseyfried) improve `Self` hygiene
1859 ident.span.with_ctxt(SyntaxContext::empty())
1864 ident = ident.modern_and_legacy();
1867 // Walk backwards up the ribs in scope.
1868 let mut module = self.graph_root;
1869 for i in (0 .. self.ribs[ns].len()).rev() {
1870 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1871 // The ident resolves to a type parameter or local variable.
1872 return Some(LexicalScopeBinding::Def(
1873 self.adjust_local_def(ns, i, def, record_used, path_span)
1877 module = match self.ribs[ns][i].kind {
1878 ModuleRibKind(module) => module,
1879 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1880 // If an invocation of this macro created `ident`, give up on `ident`
1881 // and switch to `ident`'s source from the macro definition.
1882 ident.span.remove_mark();
1888 let item = self.resolve_ident_in_module_unadjusted(
1889 ModuleOrUniformRoot::Module(module),
1896 if let Ok(binding) = item {
1897 // The ident resolves to an item.
1898 return Some(LexicalScopeBinding::Item(binding));
1902 ModuleKind::Block(..) => {}, // We can see through blocks
1907 ident.span = ident.span.modern();
1908 let mut poisoned = None;
1910 let opt_module = if let Some(node_id) = record_used_id {
1911 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1912 node_id, &mut poisoned)
1914 self.hygienic_lexical_parent(module, &mut ident.span)
1916 module = unwrap_or!(opt_module, break);
1917 let orig_current_module = self.current_module;
1918 self.current_module = module; // Lexical resolutions can never be a privacy error.
1919 let result = self.resolve_ident_in_module_unadjusted(
1920 ModuleOrUniformRoot::Module(module),
1927 self.current_module = orig_current_module;
1931 if let Some(node_id) = poisoned {
1932 self.session.buffer_lint_with_diagnostic(
1933 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1934 node_id, ident.span,
1935 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1936 lint::builtin::BuiltinLintDiagnostics::
1937 ProcMacroDeriveResolutionFallback(ident.span),
1940 return Some(LexicalScopeBinding::Item(binding))
1942 Err(Determined) => continue,
1943 Err(Undetermined) =>
1944 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1948 if !module.no_implicit_prelude {
1949 // `record_used` means that we don't try to load crates during speculative resolution
1950 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1951 if !self.session.features_untracked().extern_prelude &&
1952 !self.ignore_extern_prelude_feature {
1953 feature_err(&self.session.parse_sess, "extern_prelude",
1954 ident.span, GateIssue::Language,
1955 "access to extern crates through prelude is experimental").emit();
1958 let crate_root = self.load_extern_prelude_crate_if_needed(ident);
1960 let binding = (crate_root, ty::Visibility::Public,
1961 ident.span, Mark::root()).to_name_binding(self.arenas);
1962 return Some(LexicalScopeBinding::Item(binding));
1964 if ns == TypeNS && is_known_tool(ident.name) {
1965 let binding = (Def::ToolMod, ty::Visibility::Public,
1966 ident.span, Mark::root()).to_name_binding(self.arenas);
1967 return Some(LexicalScopeBinding::Item(binding));
1969 if let Some(prelude) = self.prelude {
1970 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1971 ModuleOrUniformRoot::Module(prelude),
1978 return Some(LexicalScopeBinding::Item(binding));
1986 fn load_extern_prelude_crate_if_needed(&mut self, ident: Ident) -> Module<'a> {
1987 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1988 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1989 self.populate_module_if_necessary(&crate_root);
1993 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
1994 -> Option<Module<'a>> {
1995 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
1996 return Some(self.macro_def_scope(span.remove_mark()));
1999 if let ModuleKind::Block(..) = module.kind {
2000 return Some(module.parent.unwrap());
2006 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2007 span: &mut Span, node_id: NodeId,
2008 poisoned: &mut Option<NodeId>)
2009 -> Option<Module<'a>> {
2010 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2014 // We need to support the next case under a deprecation warning
2017 // ---- begin: this comes from a proc macro derive
2018 // mod implementation_details {
2019 // // Note that `MyStruct` is not in scope here.
2020 // impl SomeTrait for MyStruct { ... }
2024 // So we have to fall back to the module's parent during lexical resolution in this case.
2025 if let Some(parent) = module.parent {
2026 // Inner module is inside the macro, parent module is outside of the macro.
2027 if module.expansion != parent.expansion &&
2028 module.expansion.is_descendant_of(parent.expansion) {
2029 // The macro is a proc macro derive
2030 if module.expansion.looks_like_proc_macro_derive() {
2031 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2032 *poisoned = Some(node_id);
2033 return module.parent;
2042 fn resolve_ident_in_module(&mut self,
2043 module: ModuleOrUniformRoot<'a>,
2048 -> Result<&'a NameBinding<'a>, Determinacy> {
2049 ident.span = ident.span.modern();
2050 let orig_current_module = self.current_module;
2051 if let ModuleOrUniformRoot::Module(module) = module {
2052 if let Some(def) = ident.span.adjust(module.expansion) {
2053 self.current_module = self.macro_def_scope(def);
2056 let result = self.resolve_ident_in_module_unadjusted(
2057 module, ident, ns, false, record_used, span,
2059 self.current_module = orig_current_module;
2063 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2064 let mut ctxt = ident.span.ctxt();
2065 let mark = if ident.name == keywords::DollarCrate.name() {
2066 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2067 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2068 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2069 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2070 // definitions actually produced by `macro` and `macro` definitions produced by
2071 // `macro_rules!`, but at least such configurations are not stable yet.
2072 ctxt = ctxt.modern_and_legacy();
2073 let mut iter = ctxt.marks().into_iter().rev().peekable();
2074 let mut result = None;
2075 // Find the last modern mark from the end if it exists.
2076 while let Some(&(mark, transparency)) = iter.peek() {
2077 if transparency == Transparency::Opaque {
2078 result = Some(mark);
2084 // Then find the last legacy mark from the end if it exists.
2085 for (mark, transparency) in iter {
2086 if transparency == Transparency::SemiTransparent {
2087 result = Some(mark);
2094 ctxt = ctxt.modern();
2095 ctxt.adjust(Mark::root())
2097 let module = match mark {
2098 Some(def) => self.macro_def_scope(def),
2099 None => return self.graph_root,
2101 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2104 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2105 let mut module = self.get_module(module.normal_ancestor_id);
2106 while module.span.ctxt().modern() != *ctxt {
2107 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2108 module = self.get_module(parent.normal_ancestor_id);
2115 // We maintain a list of value ribs and type ribs.
2117 // Simultaneously, we keep track of the current position in the module
2118 // graph in the `current_module` pointer. When we go to resolve a name in
2119 // the value or type namespaces, we first look through all the ribs and
2120 // then query the module graph. When we resolve a name in the module
2121 // namespace, we can skip all the ribs (since nested modules are not
2122 // allowed within blocks in Rust) and jump straight to the current module
2125 // Named implementations are handled separately. When we find a method
2126 // call, we consult the module node to find all of the implementations in
2127 // scope. This information is lazily cached in the module node. We then
2128 // generate a fake "implementation scope" containing all the
2129 // implementations thus found, for compatibility with old resolve pass.
2131 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2132 where F: FnOnce(&mut Resolver) -> T
2134 let id = self.definitions.local_def_id(id);
2135 let module = self.module_map.get(&id).cloned(); // clones a reference
2136 if let Some(module) = module {
2137 // Move down in the graph.
2138 let orig_module = replace(&mut self.current_module, module);
2139 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2140 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2142 self.finalize_current_module_macro_resolutions();
2145 self.current_module = orig_module;
2146 self.ribs[ValueNS].pop();
2147 self.ribs[TypeNS].pop();
2154 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2155 /// is returned by the given predicate function
2157 /// Stops after meeting a closure.
2158 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2159 where P: Fn(&Rib, Ident) -> Option<R>
2161 for rib in self.label_ribs.iter().rev() {
2164 // If an invocation of this macro created `ident`, give up on `ident`
2165 // and switch to `ident`'s source from the macro definition.
2166 MacroDefinition(def) => {
2167 if def == self.macro_def(ident.span.ctxt()) {
2168 ident.span.remove_mark();
2172 // Do not resolve labels across function boundary
2176 let r = pred(rib, ident);
2184 fn resolve_item(&mut self, item: &Item) {
2185 let name = item.ident.name;
2186 debug!("(resolving item) resolving {}", name);
2189 ItemKind::Ty(_, ref generics) |
2190 ItemKind::Fn(_, _, ref generics, _) |
2191 ItemKind::Existential(_, ref generics) => {
2192 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2193 |this| visit::walk_item(this, item));
2196 ItemKind::Enum(_, ref generics) |
2197 ItemKind::Struct(_, ref generics) |
2198 ItemKind::Union(_, ref generics) => {
2199 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2200 let item_def_id = this.definitions.local_def_id(item.id);
2201 if this.session.features_untracked().self_in_typedefs {
2202 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2203 visit::walk_item(this, item);
2206 visit::walk_item(this, item);
2211 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2212 self.resolve_implementation(generics,
2218 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2219 // Create a new rib for the trait-wide type parameters.
2220 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2221 let local_def_id = this.definitions.local_def_id(item.id);
2222 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2223 this.visit_generics(generics);
2224 walk_list!(this, visit_param_bound, bounds);
2226 for trait_item in trait_items {
2227 let type_parameters = HasTypeParameters(&trait_item.generics,
2228 TraitOrImplItemRibKind);
2229 this.with_type_parameter_rib(type_parameters, |this| {
2230 match trait_item.node {
2231 TraitItemKind::Const(ref ty, ref default) => {
2234 // Only impose the restrictions of
2235 // ConstRibKind for an actual constant
2236 // expression in a provided default.
2237 if let Some(ref expr) = *default{
2238 this.with_constant_rib(|this| {
2239 this.visit_expr(expr);
2243 TraitItemKind::Method(_, _) => {
2244 visit::walk_trait_item(this, trait_item)
2246 TraitItemKind::Type(..) => {
2247 visit::walk_trait_item(this, trait_item)
2249 TraitItemKind::Macro(_) => {
2250 panic!("unexpanded macro in resolve!")
2259 ItemKind::TraitAlias(ref generics, ref bounds) => {
2260 // Create a new rib for the trait-wide type parameters.
2261 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2262 let local_def_id = this.definitions.local_def_id(item.id);
2263 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2264 this.visit_generics(generics);
2265 walk_list!(this, visit_param_bound, bounds);
2270 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2271 self.with_scope(item.id, |this| {
2272 visit::walk_item(this, item);
2276 ItemKind::Static(ref ty, _, ref expr) |
2277 ItemKind::Const(ref ty, ref expr) => {
2278 self.with_item_rib(|this| {
2280 this.with_constant_rib(|this| {
2281 this.visit_expr(expr);
2286 ItemKind::Use(ref use_tree) => {
2287 // Imports are resolved as global by default, add starting root segment.
2289 segments: use_tree.prefix.make_root().into_iter().collect(),
2290 span: use_tree.span,
2292 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2295 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2296 // do nothing, these are just around to be encoded
2299 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2303 /// For the most part, use trees are desugared into `ImportDirective` instances
2304 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2305 /// there is one special case we handle here: an empty nested import like
2306 /// `a::{b::{}}`, which desugares into...no import directives.
2307 fn resolve_use_tree(
2312 use_tree: &ast::UseTree,
2315 match use_tree.kind {
2316 ast::UseTreeKind::Nested(ref items) => {
2318 segments: prefix.segments
2320 .chain(use_tree.prefix.segments.iter())
2323 span: prefix.span.to(use_tree.prefix.span),
2326 if items.len() == 0 {
2327 // Resolve prefix of an import with empty braces (issue #28388).
2328 self.smart_resolve_path_with_crate_lint(
2332 PathSource::ImportPrefix,
2333 CrateLint::UsePath { root_id, root_span },
2336 for &(ref tree, nested_id) in items {
2337 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2341 ast::UseTreeKind::Simple(..) => {},
2342 ast::UseTreeKind::Glob => {},
2346 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2347 where F: FnOnce(&mut Resolver)
2349 match type_parameters {
2350 HasTypeParameters(generics, rib_kind) => {
2351 let mut function_type_rib = Rib::new(rib_kind);
2352 let mut seen_bindings = FxHashMap();
2353 for param in &generics.params {
2355 GenericParamKind::Lifetime { .. } => {}
2356 GenericParamKind::Type { .. } => {
2357 let ident = param.ident.modern();
2358 debug!("with_type_parameter_rib: {}", param.id);
2360 if seen_bindings.contains_key(&ident) {
2361 let span = seen_bindings.get(&ident).unwrap();
2362 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2366 resolve_error(self, param.ident.span, err);
2368 seen_bindings.entry(ident).or_insert(param.ident.span);
2370 // Plain insert (no renaming).
2371 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2372 function_type_rib.bindings.insert(ident, def);
2373 self.record_def(param.id, PathResolution::new(def));
2377 self.ribs[TypeNS].push(function_type_rib);
2380 NoTypeParameters => {
2387 if let HasTypeParameters(..) = type_parameters {
2388 self.ribs[TypeNS].pop();
2392 fn with_label_rib<F>(&mut self, f: F)
2393 where F: FnOnce(&mut Resolver)
2395 self.label_ribs.push(Rib::new(NormalRibKind));
2397 self.label_ribs.pop();
2400 fn with_item_rib<F>(&mut self, f: F)
2401 where F: FnOnce(&mut Resolver)
2403 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2404 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2406 self.ribs[TypeNS].pop();
2407 self.ribs[ValueNS].pop();
2410 fn with_constant_rib<F>(&mut self, f: F)
2411 where F: FnOnce(&mut Resolver)
2413 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2414 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2416 self.label_ribs.pop();
2417 self.ribs[ValueNS].pop();
2420 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2421 where F: FnOnce(&mut Resolver) -> T
2423 // Handle nested impls (inside fn bodies)
2424 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2425 let result = f(self);
2426 self.current_self_type = previous_value;
2430 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2431 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2432 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2434 let mut new_val = None;
2435 let mut new_id = None;
2436 if let Some(trait_ref) = opt_trait_ref {
2437 let path: Vec<_> = trait_ref.path.segments.iter()
2438 .map(|seg| seg.ident)
2440 let def = self.smart_resolve_path_fragment(
2444 trait_ref.path.span,
2445 PathSource::Trait(AliasPossibility::No),
2446 CrateLint::SimplePath(trait_ref.ref_id),
2448 if def != Def::Err {
2449 new_id = Some(def.def_id());
2450 let span = trait_ref.path.span;
2451 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2458 CrateLint::SimplePath(trait_ref.ref_id),
2461 new_val = Some((module, trait_ref.clone()));
2465 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2466 let result = f(self, new_id);
2467 self.current_trait_ref = original_trait_ref;
2471 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2472 where F: FnOnce(&mut Resolver)
2474 let mut self_type_rib = Rib::new(NormalRibKind);
2476 // plain insert (no renaming, types are not currently hygienic....)
2477 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2478 self.ribs[TypeNS].push(self_type_rib);
2480 self.ribs[TypeNS].pop();
2483 fn resolve_implementation(&mut self,
2484 generics: &Generics,
2485 opt_trait_reference: &Option<TraitRef>,
2488 impl_items: &[ImplItem]) {
2489 // If applicable, create a rib for the type parameters.
2490 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2491 // Dummy self type for better errors if `Self` is used in the trait path.
2492 this.with_self_rib(Def::SelfTy(None, None), |this| {
2493 // Resolve the trait reference, if necessary.
2494 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2495 let item_def_id = this.definitions.local_def_id(item_id);
2496 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2497 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2498 // Resolve type arguments in the trait path.
2499 visit::walk_trait_ref(this, trait_ref);
2501 // Resolve the self type.
2502 this.visit_ty(self_type);
2503 // Resolve the type parameters.
2504 this.visit_generics(generics);
2505 // Resolve the items within the impl.
2506 this.with_current_self_type(self_type, |this| {
2507 for impl_item in impl_items {
2508 this.resolve_visibility(&impl_item.vis);
2510 // We also need a new scope for the impl item type parameters.
2511 let type_parameters = HasTypeParameters(&impl_item.generics,
2512 TraitOrImplItemRibKind);
2513 this.with_type_parameter_rib(type_parameters, |this| {
2514 use self::ResolutionError::*;
2515 match impl_item.node {
2516 ImplItemKind::Const(..) => {
2517 // If this is a trait impl, ensure the const
2519 this.check_trait_item(impl_item.ident,
2522 |n, s| ConstNotMemberOfTrait(n, s));
2523 this.with_constant_rib(|this|
2524 visit::walk_impl_item(this, impl_item)
2527 ImplItemKind::Method(..) => {
2528 // If this is a trait impl, ensure the method
2530 this.check_trait_item(impl_item.ident,
2533 |n, s| MethodNotMemberOfTrait(n, s));
2535 visit::walk_impl_item(this, impl_item);
2537 ImplItemKind::Type(ref ty) => {
2538 // If this is a trait impl, ensure the type
2540 this.check_trait_item(impl_item.ident,
2543 |n, s| TypeNotMemberOfTrait(n, s));
2547 ImplItemKind::Existential(ref bounds) => {
2548 // If this is a trait impl, ensure the type
2550 this.check_trait_item(impl_item.ident,
2553 |n, s| TypeNotMemberOfTrait(n, s));
2555 for bound in bounds {
2556 this.visit_param_bound(bound);
2559 ImplItemKind::Macro(_) =>
2560 panic!("unexpanded macro in resolve!"),
2571 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2572 where F: FnOnce(Name, &str) -> ResolutionError
2574 // If there is a TraitRef in scope for an impl, then the method must be in the
2576 if let Some((module, _)) = self.current_trait_ref {
2577 if self.resolve_ident_in_module(
2578 ModuleOrUniformRoot::Module(module),
2584 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2585 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2590 fn resolve_local(&mut self, local: &Local) {
2591 // Resolve the type.
2592 walk_list!(self, visit_ty, &local.ty);
2594 // Resolve the initializer.
2595 walk_list!(self, visit_expr, &local.init);
2597 // Resolve the pattern.
2598 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2601 // build a map from pattern identifiers to binding-info's.
2602 // this is done hygienically. This could arise for a macro
2603 // that expands into an or-pattern where one 'x' was from the
2604 // user and one 'x' came from the macro.
2605 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2606 let mut binding_map = FxHashMap();
2608 pat.walk(&mut |pat| {
2609 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2610 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2611 Some(Def::Local(..)) => true,
2614 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2615 binding_map.insert(ident, binding_info);
2624 // check that all of the arms in an or-pattern have exactly the
2625 // same set of bindings, with the same binding modes for each.
2626 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2627 if pats.is_empty() {
2631 let mut missing_vars = FxHashMap();
2632 let mut inconsistent_vars = FxHashMap();
2633 for (i, p) in pats.iter().enumerate() {
2634 let map_i = self.binding_mode_map(&p);
2636 for (j, q) in pats.iter().enumerate() {
2641 let map_j = self.binding_mode_map(&q);
2642 for (&key, &binding_i) in &map_i {
2643 if map_j.len() == 0 { // Account for missing bindings when
2644 let binding_error = missing_vars // map_j has none.
2646 .or_insert(BindingError {
2648 origin: BTreeSet::new(),
2649 target: BTreeSet::new(),
2651 binding_error.origin.insert(binding_i.span);
2652 binding_error.target.insert(q.span);
2654 for (&key_j, &binding_j) in &map_j {
2655 match map_i.get(&key_j) {
2656 None => { // missing binding
2657 let binding_error = missing_vars
2659 .or_insert(BindingError {
2661 origin: BTreeSet::new(),
2662 target: BTreeSet::new(),
2664 binding_error.origin.insert(binding_j.span);
2665 binding_error.target.insert(p.span);
2667 Some(binding_i) => { // check consistent binding
2668 if binding_i.binding_mode != binding_j.binding_mode {
2671 .or_insert((binding_j.span, binding_i.span));
2679 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2680 missing_vars.sort();
2681 for (_, v) in missing_vars {
2683 *v.origin.iter().next().unwrap(),
2684 ResolutionError::VariableNotBoundInPattern(v));
2686 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2687 inconsistent_vars.sort();
2688 for (name, v) in inconsistent_vars {
2689 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2693 fn resolve_arm(&mut self, arm: &Arm) {
2694 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2696 let mut bindings_list = FxHashMap();
2697 for pattern in &arm.pats {
2698 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2701 // This has to happen *after* we determine which pat_idents are variants
2702 self.check_consistent_bindings(&arm.pats);
2705 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2708 self.visit_expr(&arm.body);
2710 self.ribs[ValueNS].pop();
2713 fn resolve_block(&mut self, block: &Block) {
2714 debug!("(resolving block) entering block");
2715 // Move down in the graph, if there's an anonymous module rooted here.
2716 let orig_module = self.current_module;
2717 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2719 let mut num_macro_definition_ribs = 0;
2720 if let Some(anonymous_module) = anonymous_module {
2721 debug!("(resolving block) found anonymous module, moving down");
2722 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2723 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2724 self.current_module = anonymous_module;
2725 self.finalize_current_module_macro_resolutions();
2727 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2730 // Descend into the block.
2731 for stmt in &block.stmts {
2732 if let ast::StmtKind::Item(ref item) = stmt.node {
2733 if let ast::ItemKind::MacroDef(..) = item.node {
2734 num_macro_definition_ribs += 1;
2735 let def = self.definitions.local_def_id(item.id);
2736 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2737 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2741 self.visit_stmt(stmt);
2745 self.current_module = orig_module;
2746 for _ in 0 .. num_macro_definition_ribs {
2747 self.ribs[ValueNS].pop();
2748 self.label_ribs.pop();
2750 self.ribs[ValueNS].pop();
2751 if anonymous_module.is_some() {
2752 self.ribs[TypeNS].pop();
2754 debug!("(resolving block) leaving block");
2757 fn fresh_binding(&mut self,
2760 outer_pat_id: NodeId,
2761 pat_src: PatternSource,
2762 bindings: &mut FxHashMap<Ident, NodeId>)
2764 // Add the binding to the local ribs, if it
2765 // doesn't already exist in the bindings map. (We
2766 // must not add it if it's in the bindings map
2767 // because that breaks the assumptions later
2768 // passes make about or-patterns.)
2769 let ident = ident.modern_and_legacy();
2770 let mut def = Def::Local(pat_id);
2771 match bindings.get(&ident).cloned() {
2772 Some(id) if id == outer_pat_id => {
2773 // `Variant(a, a)`, error
2777 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2781 Some(..) if pat_src == PatternSource::FnParam => {
2782 // `fn f(a: u8, a: u8)`, error
2786 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2790 Some(..) if pat_src == PatternSource::Match ||
2791 pat_src == PatternSource::IfLet ||
2792 pat_src == PatternSource::WhileLet => {
2793 // `Variant1(a) | Variant2(a)`, ok
2794 // Reuse definition from the first `a`.
2795 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2798 span_bug!(ident.span, "two bindings with the same name from \
2799 unexpected pattern source {:?}", pat_src);
2802 // A completely fresh binding, add to the lists if it's valid.
2803 if ident.name != keywords::Invalid.name() {
2804 bindings.insert(ident, outer_pat_id);
2805 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2810 PathResolution::new(def)
2813 fn resolve_pattern(&mut self,
2815 pat_src: PatternSource,
2816 // Maps idents to the node ID for the
2817 // outermost pattern that binds them.
2818 bindings: &mut FxHashMap<Ident, NodeId>) {
2819 // Visit all direct subpatterns of this pattern.
2820 let outer_pat_id = pat.id;
2821 pat.walk(&mut |pat| {
2823 PatKind::Ident(bmode, ident, ref opt_pat) => {
2824 // First try to resolve the identifier as some existing
2825 // entity, then fall back to a fresh binding.
2826 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2828 .and_then(LexicalScopeBinding::item);
2829 let resolution = binding.map(NameBinding::def).and_then(|def| {
2830 let is_syntactic_ambiguity = opt_pat.is_none() &&
2831 bmode == BindingMode::ByValue(Mutability::Immutable);
2833 Def::StructCtor(_, CtorKind::Const) |
2834 Def::VariantCtor(_, CtorKind::Const) |
2835 Def::Const(..) if is_syntactic_ambiguity => {
2836 // Disambiguate in favor of a unit struct/variant
2837 // or constant pattern.
2838 self.record_use(ident, ValueNS, binding.unwrap(), ident.span);
2839 Some(PathResolution::new(def))
2841 Def::StructCtor(..) | Def::VariantCtor(..) |
2842 Def::Const(..) | Def::Static(..) => {
2843 // This is unambiguously a fresh binding, either syntactically
2844 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2845 // to something unusable as a pattern (e.g. constructor function),
2846 // but we still conservatively report an error, see
2847 // issues/33118#issuecomment-233962221 for one reason why.
2851 ResolutionError::BindingShadowsSomethingUnacceptable(
2852 pat_src.descr(), ident.name, binding.unwrap())
2856 Def::Fn(..) | Def::Err => {
2857 // These entities are explicitly allowed
2858 // to be shadowed by fresh bindings.
2862 span_bug!(ident.span, "unexpected definition for an \
2863 identifier in pattern: {:?}", def);
2866 }).unwrap_or_else(|| {
2867 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2870 self.record_def(pat.id, resolution);
2873 PatKind::TupleStruct(ref path, ..) => {
2874 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2877 PatKind::Path(ref qself, ref path) => {
2878 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2881 PatKind::Struct(ref path, ..) => {
2882 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2890 visit::walk_pat(self, pat);
2893 // High-level and context dependent path resolution routine.
2894 // Resolves the path and records the resolution into definition map.
2895 // If resolution fails tries several techniques to find likely
2896 // resolution candidates, suggest imports or other help, and report
2897 // errors in user friendly way.
2898 fn smart_resolve_path(&mut self,
2900 qself: Option<&QSelf>,
2904 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2907 /// A variant of `smart_resolve_path` where you also specify extra
2908 /// information about where the path came from; this extra info is
2909 /// sometimes needed for the lint that recommends rewriting
2910 /// absolute paths to `crate`, so that it knows how to frame the
2911 /// suggestion. If you are just resolving a path like `foo::bar`
2912 /// that appears...somewhere, though, then you just want
2913 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2914 /// already provides.
2915 fn smart_resolve_path_with_crate_lint(
2918 qself: Option<&QSelf>,
2921 crate_lint: CrateLint
2922 ) -> PathResolution {
2923 let segments = &path.segments.iter()
2924 .map(|seg| seg.ident)
2925 .collect::<Vec<_>>();
2926 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2929 fn smart_resolve_path_fragment(&mut self,
2931 qself: Option<&QSelf>,
2935 crate_lint: CrateLint)
2937 let ident_span = path.last().map_or(span, |ident| ident.span);
2938 let ns = source.namespace();
2939 let is_expected = &|def| source.is_expected(def);
2940 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2942 // Base error is amended with one short label and possibly some longer helps/notes.
2943 let report_errors = |this: &mut Self, def: Option<Def>| {
2944 // Make the base error.
2945 let expected = source.descr_expected();
2946 let path_str = names_to_string(path);
2947 let code = source.error_code(def.is_some());
2948 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2949 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2950 format!("not a {}", expected),
2953 let item_str = path[path.len() - 1];
2954 let item_span = path[path.len() - 1].span;
2955 let (mod_prefix, mod_str) = if path.len() == 1 {
2956 (String::new(), "this scope".to_string())
2957 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2958 (String::new(), "the crate root".to_string())
2960 let mod_path = &path[..path.len() - 1];
2961 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2962 false, span, CrateLint::No) {
2963 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
2966 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
2967 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2969 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2970 format!("not found in {}", mod_str),
2973 let code = DiagnosticId::Error(code.into());
2974 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2976 // Emit special messages for unresolved `Self` and `self`.
2977 if is_self_type(path, ns) {
2978 __diagnostic_used!(E0411);
2979 err.code(DiagnosticId::Error("E0411".into()));
2980 let available_in = if this.session.features_untracked().self_in_typedefs {
2981 "impls, traits, and type definitions"
2985 err.span_label(span, format!("`Self` is only available in {}", available_in));
2986 return (err, Vec::new());
2988 if is_self_value(path, ns) {
2989 __diagnostic_used!(E0424);
2990 err.code(DiagnosticId::Error("E0424".into()));
2991 err.span_label(span, format!("`self` value is only available in \
2992 methods with `self` parameter"));
2993 return (err, Vec::new());
2996 // Try to lookup the name in more relaxed fashion for better error reporting.
2997 let ident = *path.last().unwrap();
2998 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2999 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3000 let enum_candidates =
3001 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3002 let mut enum_candidates = enum_candidates.iter()
3003 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3004 enum_candidates.sort();
3005 for (sp, variant_path, enum_path) in enum_candidates {
3007 let msg = format!("there is an enum variant `{}`, \
3013 err.span_suggestion_with_applicability(
3015 "you can try using the variant's enum",
3017 Applicability::MachineApplicable,
3022 if path.len() == 1 && this.self_type_is_available(span) {
3023 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3024 let self_is_available = this.self_value_is_available(path[0].span, span);
3026 AssocSuggestion::Field => {
3027 err.span_suggestion_with_applicability(
3030 format!("self.{}", path_str),
3031 Applicability::MachineApplicable,
3033 if !self_is_available {
3034 err.span_label(span, format!("`self` value is only available in \
3035 methods with `self` parameter"));
3038 AssocSuggestion::MethodWithSelf if self_is_available => {
3039 err.span_suggestion_with_applicability(
3042 format!("self.{}", path_str),
3043 Applicability::MachineApplicable,
3046 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3047 err.span_suggestion_with_applicability(
3050 format!("Self::{}", path_str),
3051 Applicability::MachineApplicable,
3055 return (err, candidates);
3059 let mut levenshtein_worked = false;
3062 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3063 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3064 levenshtein_worked = true;
3067 // Try context dependent help if relaxed lookup didn't work.
3068 if let Some(def) = def {
3069 match (def, source) {
3070 (Def::Macro(..), _) => {
3071 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3072 return (err, candidates);
3074 (Def::TyAlias(..), PathSource::Trait(_)) => {
3075 err.span_label(span, "type aliases cannot be used for traits");
3076 return (err, candidates);
3078 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3079 ExprKind::Field(_, ident) => {
3080 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3082 return (err, candidates);
3084 ExprKind::MethodCall(ref segment, ..) => {
3085 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3086 path_str, segment.ident));
3087 return (err, candidates);
3091 (Def::Enum(..), PathSource::TupleStruct)
3092 | (Def::Enum(..), PathSource::Expr(..)) => {
3093 if let Some(variants) = this.collect_enum_variants(def) {
3094 err.note(&format!("did you mean to use one \
3095 of the following variants?\n{}",
3097 .map(|suggestion| path_names_to_string(suggestion))
3098 .map(|suggestion| format!("- `{}`", suggestion))
3099 .collect::<Vec<_>>()
3103 err.note("did you mean to use one of the enum's variants?");
3105 return (err, candidates);
3107 (Def::Struct(def_id), _) if ns == ValueNS => {
3108 if let Some((ctor_def, ctor_vis))
3109 = this.struct_constructors.get(&def_id).cloned() {
3110 let accessible_ctor = this.is_accessible(ctor_vis);
3111 if is_expected(ctor_def) && !accessible_ctor {
3112 err.span_label(span, format!("constructor is not visible \
3113 here due to private fields"));
3116 // HACK(estebank): find a better way to figure out that this was a
3117 // parser issue where a struct literal is being used on an expression
3118 // where a brace being opened means a block is being started. Look
3119 // ahead for the next text to see if `span` is followed by a `{`.
3120 let cm = this.session.source_map();
3123 sp = cm.next_point(sp);
3124 match cm.span_to_snippet(sp) {
3125 Ok(ref snippet) => {
3126 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3133 let followed_by_brace = match cm.span_to_snippet(sp) {
3134 Ok(ref snippet) if snippet == "{" => true,
3137 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3140 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3145 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3149 return (err, candidates);
3151 (Def::Union(..), _) |
3152 (Def::Variant(..), _) |
3153 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3154 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3156 return (err, candidates);
3158 (Def::SelfTy(..), _) if ns == ValueNS => {
3159 err.span_label(span, fallback_label);
3160 err.note("can't use `Self` as a constructor, you must use the \
3161 implemented struct");
3162 return (err, candidates);
3164 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3165 err.note("can't use a type alias as a constructor");
3166 return (err, candidates);
3173 if !levenshtein_worked {
3174 err.span_label(base_span, fallback_label);
3175 this.type_ascription_suggestion(&mut err, base_span);
3179 let report_errors = |this: &mut Self, def: Option<Def>| {
3180 let (err, candidates) = report_errors(this, def);
3181 let def_id = this.current_module.normal_ancestor_id;
3182 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3183 let better = def.is_some();
3184 this.use_injections.push(UseError { err, candidates, node_id, better });
3185 err_path_resolution()
3188 let resolution = match self.resolve_qpath_anywhere(
3194 source.defer_to_typeck(),
3195 source.global_by_default(),
3198 Some(resolution) if resolution.unresolved_segments() == 0 => {
3199 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3202 // Add a temporary hack to smooth the transition to new struct ctor
3203 // visibility rules. See #38932 for more details.
3205 if let Def::Struct(def_id) = resolution.base_def() {
3206 if let Some((ctor_def, ctor_vis))
3207 = self.struct_constructors.get(&def_id).cloned() {
3208 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3209 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3210 self.session.buffer_lint(lint, id, span,
3211 "private struct constructors are not usable through \
3212 re-exports in outer modules",
3214 res = Some(PathResolution::new(ctor_def));
3219 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3222 Some(resolution) if source.defer_to_typeck() => {
3223 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3224 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3225 // it needs to be added to the trait map.
3227 let item_name = *path.last().unwrap();
3228 let traits = self.get_traits_containing_item(item_name, ns);
3229 self.trait_map.insert(id, traits);
3233 _ => report_errors(self, None)
3236 if let PathSource::TraitItem(..) = source {} else {
3237 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3238 self.record_def(id, resolution);
3243 fn type_ascription_suggestion(&self,
3244 err: &mut DiagnosticBuilder,
3246 debug!("type_ascription_suggetion {:?}", base_span);
3247 let cm = self.session.source_map();
3248 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3249 if let Some(sp) = self.current_type_ascription.last() {
3251 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3252 sp = cm.next_point(sp);
3253 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3254 debug!("snippet {:?}", snippet);
3255 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3256 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3257 debug!("{:?} {:?}", line_sp, line_base_sp);
3259 err.span_label(base_span,
3260 "expecting a type here because of type ascription");
3261 if line_sp != line_base_sp {
3262 err.span_suggestion_short(sp,
3263 "did you mean to use `;` here instead?",
3267 } else if snippet.trim().len() != 0 {
3268 debug!("tried to find type ascription `:` token, couldn't find it");
3278 fn self_type_is_available(&mut self, span: Span) -> bool {
3279 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3280 TypeNS, None, span);
3281 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3284 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3285 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3286 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3287 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3290 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3291 fn resolve_qpath_anywhere(&mut self,
3293 qself: Option<&QSelf>,
3295 primary_ns: Namespace,
3297 defer_to_typeck: bool,
3298 global_by_default: bool,
3299 crate_lint: CrateLint)
3300 -> Option<PathResolution> {
3301 let mut fin_res = None;
3302 // FIXME: can't resolve paths in macro namespace yet, macros are
3303 // processed by the little special hack below.
3304 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3305 if i == 0 || ns != primary_ns {
3306 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3307 // If defer_to_typeck, then resolution > no resolution,
3308 // otherwise full resolution > partial resolution > no resolution.
3309 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3311 res => if fin_res.is_none() { fin_res = res },
3315 let is_global = self.macro_prelude.get(&path[0].name).cloned()
3316 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3317 if primary_ns != MacroNS && (is_global ||
3318 self.macro_names.contains(&path[0].modern())) {
3319 // Return some dummy definition, it's enough for error reporting.
3321 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3327 /// Handles paths that may refer to associated items.
3328 fn resolve_qpath(&mut self,
3330 qself: Option<&QSelf>,
3334 global_by_default: bool,
3335 crate_lint: CrateLint)
3336 -> Option<PathResolution> {
3338 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3339 ns={:?}, span={:?}, global_by_default={:?})",
3348 if let Some(qself) = qself {
3349 if qself.position == 0 {
3350 // This is a case like `<T>::B`, where there is no
3351 // trait to resolve. In that case, we leave the `B`
3352 // segment to be resolved by type-check.
3353 return Some(PathResolution::with_unresolved_segments(
3354 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3358 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3360 // Currently, `path` names the full item (`A::B::C`, in
3361 // our example). so we extract the prefix of that that is
3362 // the trait (the slice upto and including
3363 // `qself.position`). And then we recursively resolve that,
3364 // but with `qself` set to `None`.
3366 // However, setting `qself` to none (but not changing the
3367 // span) loses the information about where this path
3368 // *actually* appears, so for the purposes of the crate
3369 // lint we pass along information that this is the trait
3370 // name from a fully qualified path, and this also
3371 // contains the full span (the `CrateLint::QPathTrait`).
3372 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3373 let res = self.smart_resolve_path_fragment(
3376 &path[..qself.position + 1],
3378 PathSource::TraitItem(ns),
3379 CrateLint::QPathTrait {
3381 qpath_span: qself.path_span,
3385 // The remaining segments (the `C` in our example) will
3386 // have to be resolved by type-check, since that requires doing
3387 // trait resolution.
3388 return Some(PathResolution::with_unresolved_segments(
3389 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3393 let result = match self.resolve_path(
3401 PathResult::NonModule(path_res) => path_res,
3402 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3403 PathResolution::new(module.def().unwrap())
3405 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3406 // don't report an error right away, but try to fallback to a primitive type.
3407 // So, we are still able to successfully resolve something like
3409 // use std::u8; // bring module u8 in scope
3410 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3411 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3412 // // not to non-existent std::u8::max_value
3415 // Such behavior is required for backward compatibility.
3416 // The same fallback is used when `a` resolves to nothing.
3417 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3418 PathResult::Failed(..)
3419 if (ns == TypeNS || path.len() > 1) &&
3420 self.primitive_type_table.primitive_types
3421 .contains_key(&path[0].name) => {
3422 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3423 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3425 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3426 PathResolution::new(module.def().unwrap()),
3427 PathResult::Failed(span, msg, false) => {
3428 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3429 err_path_resolution()
3431 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3432 PathResult::Failed(..) => return None,
3433 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3436 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3437 path[0].name != keywords::CrateRoot.name() &&
3438 path[0].name != keywords::DollarCrate.name() {
3439 let unqualified_result = {
3440 match self.resolve_path(
3442 &[*path.last().unwrap()],
3448 PathResult::NonModule(path_res) => path_res.base_def(),
3449 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3450 module.def().unwrap(),
3451 _ => return Some(result),
3454 if result.base_def() == unqualified_result {
3455 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3456 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3465 base_module: Option<ModuleOrUniformRoot<'a>>,
3467 opt_ns: Option<Namespace>, // `None` indicates a module path
3470 crate_lint: CrateLint,
3471 ) -> PathResult<'a> {
3472 let mut module = base_module;
3473 let mut allow_super = true;
3474 let mut second_binding = None;
3477 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3478 path_span={:?}, crate_lint={:?})",
3486 for (i, &ident) in path.iter().enumerate() {
3487 debug!("resolve_path ident {} {:?}", i, ident);
3488 let is_last = i == path.len() - 1;
3489 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3490 let name = ident.name;
3492 allow_super &= ns == TypeNS &&
3493 (name == keywords::SelfValue.name() ||
3494 name == keywords::Super.name());
3497 if allow_super && name == keywords::Super.name() {
3498 let mut ctxt = ident.span.ctxt().modern();
3499 let self_module = match i {
3500 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3502 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3506 if let Some(self_module) = self_module {
3507 if let Some(parent) = self_module.parent {
3508 module = Some(ModuleOrUniformRoot::Module(
3509 self.resolve_self(&mut ctxt, parent)));
3513 let msg = "There are too many initial `super`s.".to_string();
3514 return PathResult::Failed(ident.span, msg, false);
3517 if name == keywords::SelfValue.name() {
3518 let mut ctxt = ident.span.ctxt().modern();
3519 module = Some(ModuleOrUniformRoot::Module(
3520 self.resolve_self(&mut ctxt, self.current_module)));
3523 if name == keywords::Extern.name() ||
3524 name == keywords::CrateRoot.name() &&
3525 self.session.features_untracked().extern_absolute_paths &&
3526 self.session.rust_2018() {
3527 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3530 if name == keywords::CrateRoot.name() ||
3531 name == keywords::Crate.name() ||
3532 name == keywords::DollarCrate.name() {
3533 // `::a::b`, `crate::a::b` or `$crate::a::b`
3534 module = Some(ModuleOrUniformRoot::Module(
3535 self.resolve_crate_root(ident)));
3541 // Report special messages for path segment keywords in wrong positions.
3542 if ident.is_path_segment_keyword() && i != 0 {
3543 let name_str = if name == keywords::CrateRoot.name() {
3544 "crate root".to_string()
3546 format!("`{}`", name)
3548 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3549 format!("global paths cannot start with {}", name_str)
3551 format!("{} in paths can only be used in start position", name_str)
3553 return PathResult::Failed(ident.span, msg, false);
3556 let binding = if let Some(module) = module {
3557 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3558 } else if opt_ns == Some(MacroNS) {
3559 assert!(ns == TypeNS);
3560 self.resolve_lexical_macro_path_segment(ident, ns, record_used, record_used,
3561 false, path_span).map(|(b, _)| b)
3563 let record_used_id =
3564 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3565 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3566 // we found a locally-imported or available item/module
3567 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3568 // we found a local variable or type param
3569 Some(LexicalScopeBinding::Def(def))
3570 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3571 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3575 _ => Err(if record_used { Determined } else { Undetermined }),
3582 second_binding = Some(binding);
3584 let def = binding.def();
3585 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3586 if let Some(next_module) = binding.module() {
3587 module = Some(ModuleOrUniformRoot::Module(next_module));
3588 } else if def == Def::ToolMod && i + 1 != path.len() {
3589 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3590 return PathResult::NonModule(PathResolution::new(def));
3591 } else if def == Def::Err {
3592 return PathResult::NonModule(err_path_resolution());
3593 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3594 self.lint_if_path_starts_with_module(
3600 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3601 def, path.len() - i - 1
3604 return PathResult::Failed(ident.span,
3605 format!("Not a module `{}`", ident),
3609 Err(Undetermined) => return PathResult::Indeterminate,
3610 Err(Determined) => {
3611 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3612 if opt_ns.is_some() && !module.is_normal() {
3613 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3614 module.def().unwrap(), path.len() - i
3618 let module_def = match module {
3619 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3622 let msg = if module_def == self.graph_root.def() {
3623 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3624 let mut candidates =
3625 self.lookup_import_candidates(name, TypeNS, is_mod);
3626 candidates.sort_by_cached_key(|c| {
3627 (c.path.segments.len(), c.path.to_string())
3629 if let Some(candidate) = candidates.get(0) {
3630 format!("Did you mean `{}`?", candidate.path)
3632 format!("Maybe a missing `extern crate {};`?", ident)
3635 format!("Use of undeclared type or module `{}`", ident)
3637 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3639 return PathResult::Failed(ident.span, msg, is_last);
3644 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3646 PathResult::Module(module.unwrap_or_else(|| {
3647 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3652 fn lint_if_path_starts_with_module(
3654 crate_lint: CrateLint,
3657 second_binding: Option<&NameBinding>,
3659 // In the 2018 edition this lint is a hard error, so nothing to do
3660 if self.session.rust_2018() {
3664 // In the 2015 edition there's no use in emitting lints unless the
3665 // crate's already enabled the feature that we're going to suggest
3666 if !self.session.features_untracked().crate_in_paths {
3670 let (diag_id, diag_span) = match crate_lint {
3671 CrateLint::No => return,
3672 CrateLint::SimplePath(id) => (id, path_span),
3673 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3674 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3677 let first_name = match path.get(0) {
3678 Some(ident) => ident.name,
3682 // We're only interested in `use` paths which should start with
3683 // `{{root}}` or `extern` currently.
3684 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3689 // If this import looks like `crate::...` it's already good
3690 Some(ident) if ident.name == keywords::Crate.name() => return,
3691 // Otherwise go below to see if it's an extern crate
3693 // If the path has length one (and it's `CrateRoot` most likely)
3694 // then we don't know whether we're gonna be importing a crate or an
3695 // item in our crate. Defer this lint to elsewhere
3699 // If the first element of our path was actually resolved to an
3700 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3701 // warning, this looks all good!
3702 if let Some(binding) = second_binding {
3703 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3704 // Careful: we still want to rewrite paths from
3705 // renamed extern crates.
3706 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3712 let diag = lint::builtin::BuiltinLintDiagnostics
3713 ::AbsPathWithModule(diag_span);
3714 self.session.buffer_lint_with_diagnostic(
3715 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3717 "absolute paths must start with `self`, `super`, \
3718 `crate`, or an external crate name in the 2018 edition",
3722 // Resolve a local definition, potentially adjusting for closures.
3723 fn adjust_local_def(&mut self,
3728 span: Span) -> Def {
3729 let ribs = &self.ribs[ns][rib_index + 1..];
3731 // An invalid forward use of a type parameter from a previous default.
3732 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3734 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3736 assert_eq!(def, Def::Err);
3742 span_bug!(span, "unexpected {:?} in bindings", def)
3744 Def::Local(node_id) => {
3747 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3748 ForwardTyParamBanRibKind => {
3749 // Nothing to do. Continue.
3751 ClosureRibKind(function_id) => {
3754 let seen = self.freevars_seen
3757 if let Some(&index) = seen.get(&node_id) {
3758 def = Def::Upvar(node_id, index, function_id);
3761 let vec = self.freevars
3764 let depth = vec.len();
3765 def = Def::Upvar(node_id, depth, function_id);
3772 seen.insert(node_id, depth);
3775 ItemRibKind | TraitOrImplItemRibKind => {
3776 // This was an attempt to access an upvar inside a
3777 // named function item. This is not allowed, so we
3780 resolve_error(self, span,
3781 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3785 ConstantItemRibKind => {
3786 // Still doesn't deal with upvars
3788 resolve_error(self, span,
3789 ResolutionError::AttemptToUseNonConstantValueInConstant);
3796 Def::TyParam(..) | Def::SelfTy(..) => {
3799 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3800 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3801 ConstantItemRibKind => {
3802 // Nothing to do. Continue.
3805 // This was an attempt to use a type parameter outside
3808 resolve_error(self, span,
3809 ResolutionError::TypeParametersFromOuterFunction(def));
3821 fn lookup_assoc_candidate<FilterFn>(&mut self,
3824 filter_fn: FilterFn)
3825 -> Option<AssocSuggestion>
3826 where FilterFn: Fn(Def) -> bool
3828 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3830 TyKind::Path(None, _) => Some(t.id),
3831 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3832 // This doesn't handle the remaining `Ty` variants as they are not
3833 // that commonly the self_type, it might be interesting to provide
3834 // support for those in future.
3839 // Fields are generally expected in the same contexts as locals.
3840 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3841 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3842 // Look for a field with the same name in the current self_type.
3843 if let Some(resolution) = self.def_map.get(&node_id) {
3844 match resolution.base_def() {
3845 Def::Struct(did) | Def::Union(did)
3846 if resolution.unresolved_segments() == 0 => {
3847 if let Some(field_names) = self.field_names.get(&did) {
3848 if field_names.iter().any(|&field_name| ident.name == field_name) {
3849 return Some(AssocSuggestion::Field);
3859 // Look for associated items in the current trait.
3860 if let Some((module, _)) = self.current_trait_ref {
3861 if let Ok(binding) = self.resolve_ident_in_module(
3862 ModuleOrUniformRoot::Module(module),
3868 let def = binding.def();
3870 return Some(if self.has_self.contains(&def.def_id()) {
3871 AssocSuggestion::MethodWithSelf
3873 AssocSuggestion::AssocItem
3882 fn lookup_typo_candidate<FilterFn>(&mut self,
3885 filter_fn: FilterFn,
3888 where FilterFn: Fn(Def) -> bool
3890 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3891 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3892 if let Some(binding) = resolution.borrow().binding {
3893 if filter_fn(binding.def()) {
3894 names.push(ident.name);
3900 let mut names = Vec::new();
3901 if path.len() == 1 {
3902 // Search in lexical scope.
3903 // Walk backwards up the ribs in scope and collect candidates.
3904 for rib in self.ribs[ns].iter().rev() {
3905 // Locals and type parameters
3906 for (ident, def) in &rib.bindings {
3907 if filter_fn(*def) {
3908 names.push(ident.name);
3912 if let ModuleRibKind(module) = rib.kind {
3913 // Items from this module
3914 add_module_candidates(module, &mut names);
3916 if let ModuleKind::Block(..) = module.kind {
3917 // We can see through blocks
3919 // Items from the prelude
3920 if !module.no_implicit_prelude {
3921 names.extend(self.extern_prelude.iter().cloned());
3922 if let Some(prelude) = self.prelude {
3923 add_module_candidates(prelude, &mut names);
3930 // Add primitive types to the mix
3931 if filter_fn(Def::PrimTy(Bool)) {
3933 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3937 // Search in module.
3938 let mod_path = &path[..path.len() - 1];
3939 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
3940 false, span, CrateLint::No) {
3941 if let ModuleOrUniformRoot::Module(module) = module {
3942 add_module_candidates(module, &mut names);
3947 let name = path[path.len() - 1].name;
3948 // Make sure error reporting is deterministic.
3949 names.sort_by_cached_key(|name| name.as_str());
3950 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3951 Some(found) if found != name => Some(found),
3956 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3957 where F: FnOnce(&mut Resolver)
3959 if let Some(label) = label {
3960 self.unused_labels.insert(id, label.ident.span);
3961 let def = Def::Label(id);
3962 self.with_label_rib(|this| {
3963 let ident = label.ident.modern_and_legacy();
3964 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
3972 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3973 self.with_resolved_label(label, id, |this| this.visit_block(block));
3976 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3977 // First, record candidate traits for this expression if it could
3978 // result in the invocation of a method call.
3980 self.record_candidate_traits_for_expr_if_necessary(expr);
3982 // Next, resolve the node.
3984 ExprKind::Path(ref qself, ref path) => {
3985 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3986 visit::walk_expr(self, expr);
3989 ExprKind::Struct(ref path, ..) => {
3990 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3991 visit::walk_expr(self, expr);
3994 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3995 let def = self.search_label(label.ident, |rib, ident| {
3996 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4000 // Search again for close matches...
4001 // Picks the first label that is "close enough", which is not necessarily
4002 // the closest match
4003 let close_match = self.search_label(label.ident, |rib, ident| {
4004 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4005 find_best_match_for_name(names, &*ident.as_str(), None)
4007 self.record_def(expr.id, err_path_resolution());
4010 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4013 Some(Def::Label(id)) => {
4014 // Since this def is a label, it is never read.
4015 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4016 self.unused_labels.remove(&id);
4019 span_bug!(expr.span, "label wasn't mapped to a label def!");
4023 // visit `break` argument if any
4024 visit::walk_expr(self, expr);
4027 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4028 self.visit_expr(subexpression);
4030 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4031 let mut bindings_list = FxHashMap();
4033 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4035 // This has to happen *after* we determine which pat_idents are variants
4036 self.check_consistent_bindings(pats);
4037 self.visit_block(if_block);
4038 self.ribs[ValueNS].pop();
4040 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4043 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4045 ExprKind::While(ref subexpression, ref block, label) => {
4046 self.with_resolved_label(label, expr.id, |this| {
4047 this.visit_expr(subexpression);
4048 this.visit_block(block);
4052 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4053 self.with_resolved_label(label, expr.id, |this| {
4054 this.visit_expr(subexpression);
4055 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4056 let mut bindings_list = FxHashMap();
4058 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4060 // This has to happen *after* we determine which pat_idents are variants
4061 this.check_consistent_bindings(pats);
4062 this.visit_block(block);
4063 this.ribs[ValueNS].pop();
4067 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4068 self.visit_expr(subexpression);
4069 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4070 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4072 self.resolve_labeled_block(label, expr.id, block);
4074 self.ribs[ValueNS].pop();
4077 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4079 // Equivalent to `visit::walk_expr` + passing some context to children.
4080 ExprKind::Field(ref subexpression, _) => {
4081 self.resolve_expr(subexpression, Some(expr));
4083 ExprKind::MethodCall(ref segment, ref arguments) => {
4084 let mut arguments = arguments.iter();
4085 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4086 for argument in arguments {
4087 self.resolve_expr(argument, None);
4089 self.visit_path_segment(expr.span, segment);
4092 ExprKind::Call(ref callee, ref arguments) => {
4093 self.resolve_expr(callee, Some(expr));
4094 for argument in arguments {
4095 self.resolve_expr(argument, None);
4098 ExprKind::Type(ref type_expr, _) => {
4099 self.current_type_ascription.push(type_expr.span);
4100 visit::walk_expr(self, expr);
4101 self.current_type_ascription.pop();
4103 // Resolve the body of async exprs inside the async closure to which they desugar
4104 ExprKind::Async(_, async_closure_id, ref block) => {
4105 let rib_kind = ClosureRibKind(async_closure_id);
4106 self.ribs[ValueNS].push(Rib::new(rib_kind));
4107 self.label_ribs.push(Rib::new(rib_kind));
4108 self.visit_block(&block);
4109 self.label_ribs.pop();
4110 self.ribs[ValueNS].pop();
4112 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4113 // resolve the arguments within the proper scopes so that usages of them inside the
4114 // closure are detected as upvars rather than normal closure arg usages.
4116 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4117 ref fn_decl, ref body, _span,
4119 let rib_kind = ClosureRibKind(expr.id);
4120 self.ribs[ValueNS].push(Rib::new(rib_kind));
4121 self.label_ribs.push(Rib::new(rib_kind));
4122 // Resolve arguments:
4123 let mut bindings_list = FxHashMap();
4124 for argument in &fn_decl.inputs {
4125 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4126 self.visit_ty(&argument.ty);
4128 // No need to resolve return type-- the outer closure return type is
4129 // FunctionRetTy::Default
4131 // Now resolve the inner closure
4133 let rib_kind = ClosureRibKind(inner_closure_id);
4134 self.ribs[ValueNS].push(Rib::new(rib_kind));
4135 self.label_ribs.push(Rib::new(rib_kind));
4136 // No need to resolve arguments: the inner closure has none.
4137 // Resolve the return type:
4138 visit::walk_fn_ret_ty(self, &fn_decl.output);
4140 self.visit_expr(body);
4141 self.label_ribs.pop();
4142 self.ribs[ValueNS].pop();
4144 self.label_ribs.pop();
4145 self.ribs[ValueNS].pop();
4148 visit::walk_expr(self, expr);
4153 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4155 ExprKind::Field(_, ident) => {
4156 // FIXME(#6890): Even though you can't treat a method like a
4157 // field, we need to add any trait methods we find that match
4158 // the field name so that we can do some nice error reporting
4159 // later on in typeck.
4160 let traits = self.get_traits_containing_item(ident, ValueNS);
4161 self.trait_map.insert(expr.id, traits);
4163 ExprKind::MethodCall(ref segment, ..) => {
4164 debug!("(recording candidate traits for expr) recording traits for {}",
4166 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4167 self.trait_map.insert(expr.id, traits);
4175 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4176 -> Vec<TraitCandidate> {
4177 debug!("(getting traits containing item) looking for '{}'", ident.name);
4179 let mut found_traits = Vec::new();
4180 // Look for the current trait.
4181 if let Some((module, _)) = self.current_trait_ref {
4182 if self.resolve_ident_in_module(
4183 ModuleOrUniformRoot::Module(module),
4189 let def_id = module.def_id().unwrap();
4190 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4194 ident.span = ident.span.modern();
4195 let mut search_module = self.current_module;
4197 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4198 search_module = unwrap_or!(
4199 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4203 if let Some(prelude) = self.prelude {
4204 if !search_module.no_implicit_prelude {
4205 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4212 fn get_traits_in_module_containing_item(&mut self,
4216 found_traits: &mut Vec<TraitCandidate>) {
4217 assert!(ns == TypeNS || ns == ValueNS);
4218 let mut traits = module.traits.borrow_mut();
4219 if traits.is_none() {
4220 let mut collected_traits = Vec::new();
4221 module.for_each_child(|name, ns, binding| {
4222 if ns != TypeNS { return }
4223 if let Def::Trait(_) = binding.def() {
4224 collected_traits.push((name, binding));
4227 *traits = Some(collected_traits.into_boxed_slice());
4230 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4231 let module = binding.module().unwrap();
4232 let mut ident = ident;
4233 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4236 if self.resolve_ident_in_module_unadjusted(
4237 ModuleOrUniformRoot::Module(module),
4244 let import_id = match binding.kind {
4245 NameBindingKind::Import { directive, .. } => {
4246 self.maybe_unused_trait_imports.insert(directive.id);
4247 self.add_to_glob_map(directive.id, trait_name);
4252 let trait_def_id = module.def_id().unwrap();
4253 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4258 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4260 namespace: Namespace,
4261 start_module: &'a ModuleData<'a>,
4263 filter_fn: FilterFn)
4264 -> Vec<ImportSuggestion>
4265 where FilterFn: Fn(Def) -> bool
4267 let mut candidates = Vec::new();
4268 let mut worklist = Vec::new();
4269 let mut seen_modules = FxHashSet();
4270 let not_local_module = crate_name != keywords::Crate.ident();
4271 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4273 while let Some((in_module,
4275 in_module_is_extern)) = worklist.pop() {
4276 self.populate_module_if_necessary(in_module);
4278 // We have to visit module children in deterministic order to avoid
4279 // instabilities in reported imports (#43552).
4280 in_module.for_each_child_stable(|ident, ns, name_binding| {
4281 // avoid imports entirely
4282 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4283 // avoid non-importable candidates as well
4284 if !name_binding.is_importable() { return; }
4286 // collect results based on the filter function
4287 if ident.name == lookup_name && ns == namespace {
4288 if filter_fn(name_binding.def()) {
4290 let mut segms = path_segments.clone();
4291 if self.session.rust_2018() {
4292 // crate-local absolute paths start with `crate::` in edition 2018
4293 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4295 0, ast::PathSegment::from_ident(crate_name)
4299 segms.push(ast::PathSegment::from_ident(ident));
4301 span: name_binding.span,
4304 // the entity is accessible in the following cases:
4305 // 1. if it's defined in the same crate, it's always
4306 // accessible (since private entities can be made public)
4307 // 2. if it's defined in another crate, it's accessible
4308 // only if both the module is public and the entity is
4309 // declared as public (due to pruning, we don't explore
4310 // outside crate private modules => no need to check this)
4311 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4312 candidates.push(ImportSuggestion { path: path });
4317 // collect submodules to explore
4318 if let Some(module) = name_binding.module() {
4320 let mut path_segments = path_segments.clone();
4321 path_segments.push(ast::PathSegment::from_ident(ident));
4323 let is_extern_crate_that_also_appears_in_prelude =
4324 name_binding.is_extern_crate() &&
4325 self.session.rust_2018();
4327 let is_visible_to_user =
4328 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4330 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4331 // add the module to the lookup
4332 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4333 if seen_modules.insert(module.def_id().unwrap()) {
4334 worklist.push((module, path_segments, is_extern));
4344 /// When name resolution fails, this method can be used to look up candidate
4345 /// entities with the expected name. It allows filtering them using the
4346 /// supplied predicate (which should be used to only accept the types of
4347 /// definitions expected e.g. traits). The lookup spans across all crates.
4349 /// NOTE: The method does not look into imports, but this is not a problem,
4350 /// since we report the definitions (thus, the de-aliased imports).
4351 fn lookup_import_candidates<FilterFn>(&mut self,
4353 namespace: Namespace,
4354 filter_fn: FilterFn)
4355 -> Vec<ImportSuggestion>
4356 where FilterFn: Fn(Def) -> bool
4358 let mut suggestions = vec![];
4361 self.lookup_import_candidates_from_module(
4362 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4366 if self.session.features_untracked().extern_prelude {
4367 let extern_prelude_names = self.extern_prelude.clone();
4368 for &krate_name in extern_prelude_names.iter() {
4369 let krate_ident = Ident::with_empty_ctxt(krate_name);
4370 let external_prelude_module = self.load_extern_prelude_crate_if_needed(krate_ident);
4373 self.lookup_import_candidates_from_module(
4374 lookup_name, namespace, external_prelude_module, krate_ident, &filter_fn
4383 fn find_module(&mut self,
4385 -> Option<(Module<'a>, ImportSuggestion)>
4387 let mut result = None;
4388 let mut worklist = Vec::new();
4389 let mut seen_modules = FxHashSet();
4390 worklist.push((self.graph_root, Vec::new()));
4392 while let Some((in_module, path_segments)) = worklist.pop() {
4393 // abort if the module is already found
4394 if result.is_some() { break; }
4396 self.populate_module_if_necessary(in_module);
4398 in_module.for_each_child_stable(|ident, _, name_binding| {
4399 // abort if the module is already found or if name_binding is private external
4400 if result.is_some() || !name_binding.vis.is_visible_locally() {
4403 if let Some(module) = name_binding.module() {
4405 let mut path_segments = path_segments.clone();
4406 path_segments.push(ast::PathSegment::from_ident(ident));
4407 if module.def() == Some(module_def) {
4409 span: name_binding.span,
4410 segments: path_segments,
4412 result = Some((module, ImportSuggestion { path: path }));
4414 // add the module to the lookup
4415 if seen_modules.insert(module.def_id().unwrap()) {
4416 worklist.push((module, path_segments));
4426 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4427 if let Def::Enum(..) = enum_def {} else {
4428 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4431 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4432 self.populate_module_if_necessary(enum_module);
4434 let mut variants = Vec::new();
4435 enum_module.for_each_child_stable(|ident, _, name_binding| {
4436 if let Def::Variant(..) = name_binding.def() {
4437 let mut segms = enum_import_suggestion.path.segments.clone();
4438 segms.push(ast::PathSegment::from_ident(ident));
4439 variants.push(Path {
4440 span: name_binding.span,
4449 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4450 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4451 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4452 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4456 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4458 ast::VisibilityKind::Public => ty::Visibility::Public,
4459 ast::VisibilityKind::Crate(..) => {
4460 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4462 ast::VisibilityKind::Inherited => {
4463 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4465 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4466 // Visibilities are resolved as global by default, add starting root segment.
4467 let segments = path.make_root().iter().chain(path.segments.iter())
4468 .map(|seg| seg.ident)
4469 .collect::<Vec<_>>();
4470 let def = self.smart_resolve_path_fragment(
4475 PathSource::Visibility,
4476 CrateLint::SimplePath(id),
4478 if def == Def::Err {
4479 ty::Visibility::Public
4481 let vis = ty::Visibility::Restricted(def.def_id());
4482 if self.is_accessible(vis) {
4485 self.session.span_err(path.span, "visibilities can only be restricted \
4486 to ancestor modules");
4487 ty::Visibility::Public
4494 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4495 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4498 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4499 vis.is_accessible_from(module.normal_ancestor_id, self)
4502 fn report_ambiguity_error(
4503 &self, name: Name, span: Span, _lexical: bool,
4504 def1: Def, is_import1: bool, is_glob1: bool, from_expansion1: bool, span1: Span,
4505 def2: Def, is_import2: bool, _is_glob2: bool, _from_expansion2: bool, span2: Span,
4507 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4508 let msg1 = format!("`{}` could refer to the name {} here", name, participle(is_import1));
4510 format!("`{}` could also refer to the name {} here", name, participle(is_import2));
4511 let note = if from_expansion1 {
4512 Some(if let Def::Macro(..) = def1 {
4513 format!("macro-expanded {} do not shadow",
4514 if is_import1 { "macro imports" } else { "macros" })
4516 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4517 if is_import1 { "imports" } else { "items" })
4519 } else if is_glob1 {
4520 Some(format!("consider adding an explicit import of `{}` to disambiguate", name))
4525 let mut err = struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
4526 err.span_note(span1, &msg1);
4528 Def::Macro(..) if span2.is_dummy() =>
4529 err.note(&format!("`{}` is also a builtin macro", name)),
4530 _ => err.span_note(span2, &msg2),
4532 if let Some(note) = note {
4538 fn report_errors(&mut self, krate: &Crate) {
4539 self.report_shadowing_errors();
4540 self.report_with_use_injections(krate);
4541 self.report_proc_macro_import(krate);
4542 let mut reported_spans = FxHashSet();
4544 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4545 let msg = "macro-expanded `macro_export` macros from the current crate \
4546 cannot be referred to by absolute paths";
4547 self.session.buffer_lint_with_diagnostic(
4548 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4549 CRATE_NODE_ID, span_use, msg,
4550 lint::builtin::BuiltinLintDiagnostics::
4551 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4555 for &AmbiguityError { span, name, b1, b2, lexical } in &self.ambiguity_errors {
4556 if reported_spans.insert(span) {
4557 self.report_ambiguity_error(
4558 name, span, lexical,
4559 b1.def(), b1.is_import(), b1.is_glob_import(),
4560 b1.expansion != Mark::root(), b1.span,
4561 b2.def(), b2.is_import(), b2.is_glob_import(),
4562 b2.expansion != Mark::root(), b2.span,
4567 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4568 if !reported_spans.insert(span) { continue }
4569 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4573 fn report_with_use_injections(&mut self, krate: &Crate) {
4574 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4575 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4576 if !candidates.is_empty() {
4577 show_candidates(&mut err, span, &candidates, better, found_use);
4583 fn report_shadowing_errors(&mut self) {
4584 let mut reported_errors = FxHashSet();
4585 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4586 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4587 reported_errors.insert((binding.ident, binding.span)) {
4588 let msg = format!("`{}` is already in scope", binding.ident);
4589 self.session.struct_span_err(binding.span, &msg)
4590 .note("macro-expanded `macro_rules!`s may not shadow \
4591 existing macros (see RFC 1560)")
4597 fn report_conflict<'b>(&mut self,
4601 new_binding: &NameBinding<'b>,
4602 old_binding: &NameBinding<'b>) {
4603 // Error on the second of two conflicting names
4604 if old_binding.span.lo() > new_binding.span.lo() {
4605 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4608 let container = match parent.kind {
4609 ModuleKind::Def(Def::Mod(_), _) => "module",
4610 ModuleKind::Def(Def::Trait(_), _) => "trait",
4611 ModuleKind::Block(..) => "block",
4615 let old_noun = match old_binding.is_import() {
4617 false => "definition",
4620 let new_participle = match new_binding.is_import() {
4625 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4627 if let Some(s) = self.name_already_seen.get(&name) {
4633 let old_kind = match (ns, old_binding.module()) {
4634 (ValueNS, _) => "value",
4635 (MacroNS, _) => "macro",
4636 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4637 (TypeNS, Some(module)) if module.is_normal() => "module",
4638 (TypeNS, Some(module)) if module.is_trait() => "trait",
4639 (TypeNS, _) => "type",
4642 let msg = format!("the name `{}` is defined multiple times", name);
4644 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4645 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4646 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4647 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4648 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4650 _ => match (old_binding.is_import(), new_binding.is_import()) {
4651 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4652 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4653 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4657 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4662 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4663 if !old_binding.span.is_dummy() {
4664 err.span_label(self.session.source_map().def_span(old_binding.span),
4665 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4668 // See https://github.com/rust-lang/rust/issues/32354
4669 if old_binding.is_import() || new_binding.is_import() {
4670 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4676 let cm = self.session.source_map();
4677 let rename_msg = "You can use `as` to change the binding name of the import";
4679 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4680 binding.is_renamed_extern_crate()) {
4681 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4682 format!("Other{}", name)
4684 format!("other_{}", name)
4687 err.span_suggestion_with_applicability(
4690 if snippet.ends_with(';') {
4691 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4693 format!("{} as {}", snippet, suggested_name)
4695 Applicability::MachineApplicable,
4698 err.span_label(binding.span, rename_msg);
4703 self.name_already_seen.insert(name, span);
4707 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4708 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4711 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4712 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4715 fn names_to_string(idents: &[Ident]) -> String {
4716 let mut result = String::new();
4717 for (i, ident) in idents.iter()
4718 .filter(|ident| ident.name != keywords::CrateRoot.name())
4721 result.push_str("::");
4723 result.push_str(&ident.as_str());
4728 fn path_names_to_string(path: &Path) -> String {
4729 names_to_string(&path.segments.iter()
4730 .map(|seg| seg.ident)
4731 .collect::<Vec<_>>())
4734 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4735 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4736 let variant_path = &suggestion.path;
4737 let variant_path_string = path_names_to_string(variant_path);
4739 let path_len = suggestion.path.segments.len();
4740 let enum_path = ast::Path {
4741 span: suggestion.path.span,
4742 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4744 let enum_path_string = path_names_to_string(&enum_path);
4746 (suggestion.path.span, variant_path_string, enum_path_string)
4750 /// When an entity with a given name is not available in scope, we search for
4751 /// entities with that name in all crates. This method allows outputting the
4752 /// results of this search in a programmer-friendly way
4753 fn show_candidates(err: &mut DiagnosticBuilder,
4754 // This is `None` if all placement locations are inside expansions
4756 candidates: &[ImportSuggestion],
4760 // we want consistent results across executions, but candidates are produced
4761 // by iterating through a hash map, so make sure they are ordered:
4762 let mut path_strings: Vec<_> =
4763 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4764 path_strings.sort();
4766 let better = if better { "better " } else { "" };
4767 let msg_diff = match path_strings.len() {
4768 1 => " is found in another module, you can import it",
4769 _ => "s are found in other modules, you can import them",
4771 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4773 if let Some(span) = span {
4774 for candidate in &mut path_strings {
4775 // produce an additional newline to separate the new use statement
4776 // from the directly following item.
4777 let additional_newline = if found_use {
4782 *candidate = format!("use {};\n{}", candidate, additional_newline);
4785 err.span_suggestions(span, &msg, path_strings);
4789 for candidate in path_strings {
4791 msg.push_str(&candidate);
4796 /// A somewhat inefficient routine to obtain the name of a module.
4797 fn module_to_string(module: Module) -> Option<String> {
4798 let mut names = Vec::new();
4800 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4801 if let ModuleKind::Def(_, name) = module.kind {
4802 if let Some(parent) = module.parent {
4803 names.push(Ident::with_empty_ctxt(name));
4804 collect_mod(names, parent);
4807 // danger, shouldn't be ident?
4808 names.push(Ident::from_str("<opaque>"));
4809 collect_mod(names, module.parent.unwrap());
4812 collect_mod(&mut names, module);
4814 if names.is_empty() {
4817 Some(names_to_string(&names.into_iter()
4819 .collect::<Vec<_>>()))
4822 fn err_path_resolution() -> PathResolution {
4823 PathResolution::new(Def::Err)
4826 #[derive(PartialEq,Copy, Clone)]
4827 pub enum MakeGlobMap {
4832 #[derive(Copy, Clone, Debug)]
4834 /// Do not issue the lint
4837 /// This lint applies to some random path like `impl ::foo::Bar`
4838 /// or whatever. In this case, we can take the span of that path.
4841 /// This lint comes from a `use` statement. In this case, what we
4842 /// care about really is the *root* `use` statement; e.g., if we
4843 /// have nested things like `use a::{b, c}`, we care about the
4845 UsePath { root_id: NodeId, root_span: Span },
4847 /// This is the "trait item" from a fully qualified path. For example,
4848 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4849 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4850 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4854 fn node_id(&self) -> Option<NodeId> {
4856 CrateLint::No => None,
4857 CrateLint::SimplePath(id) |
4858 CrateLint::UsePath { root_id: id, .. } |
4859 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4864 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }