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 #![feature(rustc_diagnostic_macros)]
18 #![feature(slice_sort_by_cached_key)]
24 extern crate syntax_pos;
25 extern crate rustc_errors as errors;
29 extern crate rustc_data_structures;
30 extern crate rustc_metadata;
32 pub use rustc::hir::def::{Namespace, PerNS};
34 use self::TypeParameters::*;
37 use rustc::hir::map::{Definitions, DefCollector};
38 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
39 use rustc::middle::cstore::CrateStore;
40 use rustc::session::Session;
42 use rustc::hir::def::*;
43 use rustc::hir::def::Namespace::*;
44 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
46 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
47 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
49 use rustc_metadata::creader::CrateLoader;
50 use rustc_metadata::cstore::CStore;
52 use syntax::codemap::CodeMap;
53 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
54 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
55 use syntax::ext::base::SyntaxExtension;
56 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
57 use syntax::ext::base::MacroKind;
58 use syntax::symbol::{Symbol, keywords};
59 use syntax::util::lev_distance::find_best_match_for_name;
61 use syntax::visit::{self, FnKind, Visitor};
63 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
64 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
65 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
66 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
67 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
68 use syntax::feature_gate::{feature_err, GateIssue};
71 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
72 use errors::{DiagnosticBuilder, DiagnosticId};
74 use std::cell::{Cell, RefCell};
76 use std::collections::BTreeSet;
79 use std::mem::replace;
80 use rustc_data_structures::sync::Lrc;
82 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
83 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
85 // NB: This module needs to be declared first so diagnostics are
86 // registered before they are used.
91 mod build_reduced_graph;
94 fn is_known_tool(name: Name) -> bool {
95 ["clippy", "rustfmt"].contains(&&*name.as_str())
98 /// A free importable items suggested in case of resolution failure.
99 struct ImportSuggestion {
103 /// A field or associated item from self type suggested in case of resolution failure.
104 enum AssocSuggestion {
111 struct BindingError {
113 origin: BTreeSet<Span>,
114 target: BTreeSet<Span>,
117 impl PartialOrd for BindingError {
118 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
119 Some(self.cmp(other))
123 impl PartialEq for BindingError {
124 fn eq(&self, other: &BindingError) -> bool {
125 self.name == other.name
129 impl Ord for BindingError {
130 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
131 self.name.cmp(&other.name)
135 enum ResolutionError<'a> {
136 /// error E0401: can't use type parameters from outer function
137 TypeParametersFromOuterFunction(Def),
138 /// error E0403: the name is already used for a type parameter in this type parameter list
139 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
140 /// error E0407: method is not a member of trait
141 MethodNotMemberOfTrait(Name, &'a str),
142 /// error E0437: type is not a member of trait
143 TypeNotMemberOfTrait(Name, &'a str),
144 /// error E0438: const is not a member of trait
145 ConstNotMemberOfTrait(Name, &'a str),
146 /// error E0408: variable `{}` is not bound in all patterns
147 VariableNotBoundInPattern(&'a BindingError),
148 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
149 VariableBoundWithDifferentMode(Name, Span),
150 /// error E0415: identifier is bound more than once in this parameter list
151 IdentifierBoundMoreThanOnceInParameterList(&'a str),
152 /// error E0416: identifier is bound more than once in the same pattern
153 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
154 /// error E0426: use of undeclared label
155 UndeclaredLabel(&'a str, Option<Name>),
156 /// error E0429: `self` imports are only allowed within a { } list
157 SelfImportsOnlyAllowedWithin,
158 /// error E0430: `self` import can only appear once in the list
159 SelfImportCanOnlyAppearOnceInTheList,
160 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
161 SelfImportOnlyInImportListWithNonEmptyPrefix,
162 /// error E0432: unresolved import
163 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
164 /// error E0433: failed to resolve
165 FailedToResolve(&'a str),
166 /// error E0434: can't capture dynamic environment in a fn item
167 CannotCaptureDynamicEnvironmentInFnItem,
168 /// error E0435: attempt to use a non-constant value in a constant
169 AttemptToUseNonConstantValueInConstant,
170 /// error E0530: X bindings cannot shadow Ys
171 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
172 /// error E0128: type parameters with a default cannot use forward declared identifiers
173 ForwardDeclaredTyParam,
176 /// Combines an error with provided span and emits it
178 /// This takes the error provided, combines it with the span and any additional spans inside the
179 /// error and emits it.
180 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
182 resolution_error: ResolutionError<'a>) {
183 resolve_struct_error(resolver, span, resolution_error).emit();
186 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
188 resolution_error: ResolutionError<'a>)
189 -> DiagnosticBuilder<'sess> {
190 match resolution_error {
191 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
192 let mut err = struct_span_err!(resolver.session,
195 "can't use type parameters from outer function");
196 err.span_label(span, "use of type variable from outer function");
198 let cm = resolver.session.codemap();
200 Def::SelfTy(_, maybe_impl_defid) => {
201 if let Some(impl_span) = maybe_impl_defid.map_or(None,
202 |def_id| resolver.definitions.opt_span(def_id)) {
203 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
204 "`Self` type implicitely declared here, on the `impl`");
207 Def::TyParam(typaram_defid) => {
208 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
209 err.span_label(typaram_span, "type variable from outer function");
213 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
218 // Try to retrieve the span of the function signature and generate a new message with
219 // a local type parameter
220 let sugg_msg = "try using a local type parameter instead";
221 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
222 // Suggest the modification to the user
223 err.span_suggestion(sugg_span,
226 } else if let Some(sp) = cm.generate_fn_name_span(span) {
227 err.span_label(sp, "try adding a local type parameter in this method instead");
229 err.help("try using a local type parameter instead");
234 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
235 let mut err = struct_span_err!(resolver.session,
238 "the name `{}` is already used for a type parameter \
239 in this type parameter list",
241 err.span_label(span, "already used");
242 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
245 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
246 let mut err = struct_span_err!(resolver.session,
249 "method `{}` is not a member of trait `{}`",
252 err.span_label(span, format!("not a member of trait `{}`", trait_));
255 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
256 let mut err = struct_span_err!(resolver.session,
259 "type `{}` is not a member of trait `{}`",
262 err.span_label(span, format!("not a member of trait `{}`", trait_));
265 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
266 let mut err = struct_span_err!(resolver.session,
269 "const `{}` is not a member of trait `{}`",
272 err.span_label(span, format!("not a member of trait `{}`", trait_));
275 ResolutionError::VariableNotBoundInPattern(binding_error) => {
276 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
277 let msp = MultiSpan::from_spans(target_sp.clone());
278 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
279 let mut err = resolver.session.struct_span_err_with_code(
282 DiagnosticId::Error("E0408".into()),
284 for sp in target_sp {
285 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
287 let origin_sp = binding_error.origin.iter().cloned();
288 for sp in origin_sp {
289 err.span_label(sp, "variable not in all patterns");
293 ResolutionError::VariableBoundWithDifferentMode(variable_name,
294 first_binding_span) => {
295 let mut err = struct_span_err!(resolver.session,
298 "variable `{}` is bound in inconsistent \
299 ways within the same match arm",
301 err.span_label(span, "bound in different ways");
302 err.span_label(first_binding_span, "first binding");
305 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
306 let mut err = struct_span_err!(resolver.session,
309 "identifier `{}` is bound more than once in this parameter list",
311 err.span_label(span, "used as parameter more than once");
314 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
315 let mut err = struct_span_err!(resolver.session,
318 "identifier `{}` is bound more than once in the same pattern",
320 err.span_label(span, "used in a pattern more than once");
323 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
324 let mut err = struct_span_err!(resolver.session,
327 "use of undeclared label `{}`",
329 if let Some(lev_candidate) = lev_candidate {
330 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
332 err.span_label(span, format!("undeclared label `{}`", name));
336 ResolutionError::SelfImportsOnlyAllowedWithin => {
337 struct_span_err!(resolver.session,
341 "`self` imports are only allowed within a { } list")
343 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
344 let mut err = struct_span_err!(resolver.session, span, E0430,
345 "`self` import can only appear once in an import list");
346 err.span_label(span, "can only appear once in an import list");
349 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
350 let mut err = struct_span_err!(resolver.session, span, E0431,
351 "`self` import can only appear in an import list with \
352 a non-empty prefix");
353 err.span_label(span, "can only appear in an import list with a non-empty prefix");
356 ResolutionError::UnresolvedImport(name) => {
357 let (span, msg) = match name {
358 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
359 None => (span, "unresolved import".to_owned()),
361 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
362 if let Some((_, _, p)) = name {
363 err.span_label(span, p);
367 ResolutionError::FailedToResolve(msg) => {
368 let mut err = struct_span_err!(resolver.session, span, E0433,
369 "failed to resolve. {}", msg);
370 err.span_label(span, msg);
373 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
374 let mut err = struct_span_err!(resolver.session,
378 "can't capture dynamic environment in a fn item");
379 err.help("use the `|| { ... }` closure form instead");
382 ResolutionError::AttemptToUseNonConstantValueInConstant => {
383 let mut err = struct_span_err!(resolver.session, span, E0435,
384 "attempt to use a non-constant value in a constant");
385 err.span_label(span, "non-constant value");
388 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
389 let shadows_what = PathResolution::new(binding.def()).kind_name();
390 let mut err = struct_span_err!(resolver.session,
393 "{}s cannot shadow {}s", what_binding, shadows_what);
394 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
395 let participle = if binding.is_import() { "imported" } else { "defined" };
396 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
397 err.span_label(binding.span, msg);
400 ResolutionError::ForwardDeclaredTyParam => {
401 let mut err = struct_span_err!(resolver.session, span, E0128,
402 "type parameters with a default cannot use \
403 forward declared identifiers");
405 span, "defaulted type parameters cannot be forward declared".to_string());
411 /// Adjust the impl span so that just the `impl` keyword is taken by removing
412 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
413 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
415 /// Attention: The method used is very fragile since it essentially duplicates the work of the
416 /// parser. If you need to use this function or something similar, please consider updating the
417 /// codemap functions and this function to something more robust.
418 fn reduce_impl_span_to_impl_keyword(cm: &CodeMap, impl_span: Span) -> Span {
419 let impl_span = cm.span_until_char(impl_span, '<');
420 let impl_span = cm.span_until_whitespace(impl_span);
424 #[derive(Copy, Clone, Debug)]
427 binding_mode: BindingMode,
430 /// Map from the name in a pattern to its binding mode.
431 type BindingMap = FxHashMap<Ident, BindingInfo>;
433 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
444 fn descr(self) -> &'static str {
446 PatternSource::Match => "match binding",
447 PatternSource::IfLet => "if let binding",
448 PatternSource::WhileLet => "while let binding",
449 PatternSource::Let => "let binding",
450 PatternSource::For => "for binding",
451 PatternSource::FnParam => "function parameter",
456 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
457 enum AliasPossibility {
462 #[derive(Copy, Clone, Debug)]
463 enum PathSource<'a> {
464 // Type paths `Path`.
466 // Trait paths in bounds or impls.
467 Trait(AliasPossibility),
468 // Expression paths `path`, with optional parent context.
469 Expr(Option<&'a Expr>),
470 // Paths in path patterns `Path`.
472 // Paths in struct expressions and patterns `Path { .. }`.
474 // Paths in tuple struct patterns `Path(..)`.
476 // `m::A::B` in `<T as m::A>::B::C`.
477 TraitItem(Namespace),
478 // Path in `pub(path)`
480 // Path in `use a::b::{...};`
484 impl<'a> PathSource<'a> {
485 fn namespace(self) -> Namespace {
487 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
488 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
489 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
490 PathSource::TraitItem(ns) => ns,
494 fn global_by_default(self) -> bool {
496 PathSource::Visibility | PathSource::ImportPrefix => true,
497 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
498 PathSource::Struct | PathSource::TupleStruct |
499 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
503 fn defer_to_typeck(self) -> bool {
505 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
506 PathSource::Struct | PathSource::TupleStruct => true,
507 PathSource::Trait(_) | PathSource::TraitItem(..) |
508 PathSource::Visibility | PathSource::ImportPrefix => false,
512 fn descr_expected(self) -> &'static str {
514 PathSource::Type => "type",
515 PathSource::Trait(_) => "trait",
516 PathSource::Pat => "unit struct/variant or constant",
517 PathSource::Struct => "struct, variant or union type",
518 PathSource::TupleStruct => "tuple struct/variant",
519 PathSource::Visibility => "module",
520 PathSource::ImportPrefix => "module or enum",
521 PathSource::TraitItem(ns) => match ns {
522 TypeNS => "associated type",
523 ValueNS => "method or associated constant",
524 MacroNS => bug!("associated macro"),
526 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
527 // "function" here means "anything callable" rather than `Def::Fn`,
528 // this is not precise but usually more helpful than just "value".
529 Some(&ExprKind::Call(..)) => "function",
535 fn is_expected(self, def: Def) -> bool {
537 PathSource::Type => match def {
538 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
539 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
540 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
541 Def::Existential(..) |
542 Def::TyForeign(..) => true,
545 PathSource::Trait(AliasPossibility::No) => match def {
546 Def::Trait(..) => true,
549 PathSource::Trait(AliasPossibility::Maybe) => match def {
550 Def::Trait(..) => true,
551 Def::TraitAlias(..) => true,
554 PathSource::Expr(..) => match def {
555 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
556 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
557 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
558 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
561 PathSource::Pat => match def {
562 Def::StructCtor(_, CtorKind::Const) |
563 Def::VariantCtor(_, CtorKind::Const) |
564 Def::Const(..) | Def::AssociatedConst(..) => true,
567 PathSource::TupleStruct => match def {
568 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
571 PathSource::Struct => match def {
572 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
573 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
576 PathSource::TraitItem(ns) => match def {
577 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
578 Def::AssociatedTy(..) if ns == TypeNS => true,
581 PathSource::ImportPrefix => match def {
582 Def::Mod(..) | Def::Enum(..) => true,
585 PathSource::Visibility => match def {
586 Def::Mod(..) => true,
592 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
593 __diagnostic_used!(E0404);
594 __diagnostic_used!(E0405);
595 __diagnostic_used!(E0412);
596 __diagnostic_used!(E0422);
597 __diagnostic_used!(E0423);
598 __diagnostic_used!(E0425);
599 __diagnostic_used!(E0531);
600 __diagnostic_used!(E0532);
601 __diagnostic_used!(E0573);
602 __diagnostic_used!(E0574);
603 __diagnostic_used!(E0575);
604 __diagnostic_used!(E0576);
605 __diagnostic_used!(E0577);
606 __diagnostic_used!(E0578);
607 match (self, has_unexpected_resolution) {
608 (PathSource::Trait(_), true) => "E0404",
609 (PathSource::Trait(_), false) => "E0405",
610 (PathSource::Type, true) => "E0573",
611 (PathSource::Type, false) => "E0412",
612 (PathSource::Struct, true) => "E0574",
613 (PathSource::Struct, false) => "E0422",
614 (PathSource::Expr(..), true) => "E0423",
615 (PathSource::Expr(..), false) => "E0425",
616 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
617 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
618 (PathSource::TraitItem(..), true) => "E0575",
619 (PathSource::TraitItem(..), false) => "E0576",
620 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
621 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
626 struct UsePlacementFinder {
627 target_module: NodeId,
632 impl UsePlacementFinder {
633 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
634 let mut finder = UsePlacementFinder {
639 visit::walk_crate(&mut finder, krate);
640 (finder.span, finder.found_use)
644 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
647 module: &'tcx ast::Mod,
649 _: &[ast::Attribute],
652 if self.span.is_some() {
655 if node_id != self.target_module {
656 visit::walk_mod(self, module);
659 // find a use statement
660 for item in &module.items {
662 ItemKind::Use(..) => {
663 // don't suggest placing a use before the prelude
664 // import or other generated ones
665 if item.span.ctxt().outer().expn_info().is_none() {
666 self.span = Some(item.span.shrink_to_lo());
667 self.found_use = true;
671 // don't place use before extern crate
672 ItemKind::ExternCrate(_) => {}
673 // but place them before the first other item
674 _ => if self.span.map_or(true, |span| item.span < span ) {
675 if item.span.ctxt().outer().expn_info().is_none() {
676 // don't insert between attributes and an item
677 if item.attrs.is_empty() {
678 self.span = Some(item.span.shrink_to_lo());
680 // find the first attribute on the item
681 for attr in &item.attrs {
682 if self.span.map_or(true, |span| attr.span < span) {
683 self.span = Some(attr.span.shrink_to_lo());
694 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
695 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
696 fn visit_item(&mut self, item: &'tcx Item) {
697 self.resolve_item(item);
699 fn visit_arm(&mut self, arm: &'tcx Arm) {
700 self.resolve_arm(arm);
702 fn visit_block(&mut self, block: &'tcx Block) {
703 self.resolve_block(block);
705 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
706 self.with_constant_rib(|this| {
707 visit::walk_anon_const(this, constant);
710 fn visit_expr(&mut self, expr: &'tcx Expr) {
711 self.resolve_expr(expr, None);
713 fn visit_local(&mut self, local: &'tcx Local) {
714 self.resolve_local(local);
716 fn visit_ty(&mut self, ty: &'tcx Ty) {
718 TyKind::Path(ref qself, ref path) => {
719 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
721 TyKind::ImplicitSelf => {
722 let self_ty = keywords::SelfType.ident();
723 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
724 .map_or(Def::Err, |d| d.def());
725 self.record_def(ty.id, PathResolution::new(def));
729 visit::walk_ty(self, ty);
731 fn visit_poly_trait_ref(&mut self,
732 tref: &'tcx ast::PolyTraitRef,
733 m: &'tcx ast::TraitBoundModifier) {
734 self.smart_resolve_path(tref.trait_ref.ref_id, None,
735 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
736 visit::walk_poly_trait_ref(self, tref, m);
738 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
739 let type_parameters = match foreign_item.node {
740 ForeignItemKind::Fn(_, ref generics) => {
741 HasTypeParameters(generics, ItemRibKind)
743 ForeignItemKind::Static(..) => NoTypeParameters,
744 ForeignItemKind::Ty => NoTypeParameters,
745 ForeignItemKind::Macro(..) => NoTypeParameters,
747 self.with_type_parameter_rib(type_parameters, |this| {
748 visit::walk_foreign_item(this, foreign_item);
751 fn visit_fn(&mut self,
752 function_kind: FnKind<'tcx>,
753 declaration: &'tcx FnDecl,
757 let (rib_kind, asyncness) = match function_kind {
758 FnKind::ItemFn(_, ref header, ..) =>
759 (ItemRibKind, header.asyncness),
760 FnKind::Method(_, ref sig, _, _) =>
761 (TraitOrImplItemRibKind, sig.header.asyncness),
762 FnKind::Closure(_) =>
763 // Async closures aren't resolved through `visit_fn`-- they're
764 // processed separately
765 (ClosureRibKind(node_id), IsAsync::NotAsync),
768 // Create a value rib for the function.
769 self.ribs[ValueNS].push(Rib::new(rib_kind));
771 // Create a label rib for the function.
772 self.label_ribs.push(Rib::new(rib_kind));
774 // Add each argument to the rib.
775 let mut bindings_list = FxHashMap();
776 for argument in &declaration.inputs {
777 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
779 self.visit_ty(&argument.ty);
781 debug!("(resolving function) recorded argument");
783 visit::walk_fn_ret_ty(self, &declaration.output);
785 // Resolve the function body, potentially inside the body of an async closure
786 if let IsAsync::Async { closure_id, .. } = asyncness {
787 let rib_kind = ClosureRibKind(closure_id);
788 self.ribs[ValueNS].push(Rib::new(rib_kind));
789 self.label_ribs.push(Rib::new(rib_kind));
792 match function_kind {
793 FnKind::ItemFn(.., body) |
794 FnKind::Method(.., body) => {
795 self.visit_block(body);
797 FnKind::Closure(body) => {
798 self.visit_expr(body);
802 // Leave the body of the async closure
803 if asyncness.is_async() {
804 self.label_ribs.pop();
805 self.ribs[ValueNS].pop();
808 debug!("(resolving function) leaving function");
810 self.label_ribs.pop();
811 self.ribs[ValueNS].pop();
813 fn visit_generics(&mut self, generics: &'tcx Generics) {
814 // For type parameter defaults, we have to ban access
815 // to following type parameters, as the Substs can only
816 // provide previous type parameters as they're built. We
817 // put all the parameters on the ban list and then remove
818 // them one by one as they are processed and become available.
819 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
820 let mut found_default = false;
821 default_ban_rib.bindings.extend(generics.params.iter()
822 .filter_map(|param| match param.kind {
823 GenericParamKind::Lifetime { .. } => None,
824 GenericParamKind::Type { ref default, .. } => {
825 if found_default || default.is_some() {
826 found_default = true;
827 return Some((Ident::with_empty_ctxt(param.ident.name), Def::Err));
833 for param in &generics.params {
835 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
836 GenericParamKind::Type { ref default, .. } => {
837 for bound in ¶m.bounds {
838 self.visit_param_bound(bound);
841 if let Some(ref ty) = default {
842 self.ribs[TypeNS].push(default_ban_rib);
844 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
847 // Allow all following defaults to refer to this type parameter.
848 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
852 for p in &generics.where_clause.predicates {
853 self.visit_where_predicate(p);
858 #[derive(Copy, Clone)]
859 enum TypeParameters<'a, 'b> {
861 HasTypeParameters(// Type parameters.
864 // The kind of the rib used for type parameters.
868 /// The rib kind controls the translation of local
869 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
870 #[derive(Copy, Clone, Debug)]
872 /// No translation needs to be applied.
875 /// We passed through a closure scope at the given node ID.
876 /// Translate upvars as appropriate.
877 ClosureRibKind(NodeId /* func id */),
879 /// We passed through an impl or trait and are now in one of its
880 /// methods or associated types. Allow references to ty params that impl or trait
881 /// binds. Disallow any other upvars (including other ty params that are
883 TraitOrImplItemRibKind,
885 /// We passed through an item scope. Disallow upvars.
888 /// We're in a constant item. Can't refer to dynamic stuff.
891 /// We passed through a module.
892 ModuleRibKind(Module<'a>),
894 /// We passed through a `macro_rules!` statement
895 MacroDefinition(DefId),
897 /// All bindings in this rib are type parameters that can't be used
898 /// from the default of a type parameter because they're not declared
899 /// before said type parameter. Also see the `visit_generics` override.
900 ForwardTyParamBanRibKind,
905 /// A rib represents a scope names can live in. Note that these appear in many places, not just
906 /// around braces. At any place where the list of accessible names (of the given namespace)
907 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
908 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
911 /// Different [rib kinds](enum.RibKind) are transparent for different names.
913 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
914 /// resolving, the name is looked up from inside out.
917 bindings: FxHashMap<Ident, Def>,
922 fn new(kind: RibKind<'a>) -> Rib<'a> {
924 bindings: FxHashMap(),
930 /// An intermediate resolution result.
932 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
933 /// items are visible in their whole block, while defs only from the place they are defined
935 enum LexicalScopeBinding<'a> {
936 Item(&'a NameBinding<'a>),
940 impl<'a> LexicalScopeBinding<'a> {
941 fn item(self) -> Option<&'a NameBinding<'a>> {
943 LexicalScopeBinding::Item(binding) => Some(binding),
948 fn def(self) -> Def {
950 LexicalScopeBinding::Item(binding) => binding.def(),
951 LexicalScopeBinding::Def(def) => def,
956 #[derive(Copy, Clone, Debug)]
957 pub enum ModuleOrUniformRoot<'a> {
961 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
962 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
963 /// but *not* `extern`), in the Rust 2018 edition.
967 #[derive(Clone, Debug)]
968 enum PathResult<'a> {
969 Module(ModuleOrUniformRoot<'a>),
970 NonModule(PathResolution),
972 Failed(Span, String, bool /* is the error from the last segment? */),
976 /// An anonymous module, eg. just a block.
981 /// { // This is an anonymous module
982 /// f(); // This resolves to (2) as we are inside the block.
985 /// f(); // Resolves to (1)
989 /// Any module with a name.
993 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
994 /// * A trait or an enum (it implicitly contains associated types, methods and variant
999 /// One node in the tree of modules.
1000 pub struct ModuleData<'a> {
1001 parent: Option<Module<'a>>,
1004 // The def id of the closest normal module (`mod`) ancestor (including this module).
1005 normal_ancestor_id: DefId,
1007 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1008 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, MacroKind, Option<Def>)>>,
1009 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1011 // Macro invocations that can expand into items in this module.
1012 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1014 no_implicit_prelude: bool,
1016 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1017 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1019 // Used to memoize the traits in this module for faster searches through all traits in scope.
1020 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1022 // Whether this module is populated. If not populated, any attempt to
1023 // access the children must be preceded with a
1024 // `populate_module_if_necessary` call.
1025 populated: Cell<bool>,
1027 /// Span of the module itself. Used for error reporting.
1033 type Module<'a> = &'a ModuleData<'a>;
1035 impl<'a> ModuleData<'a> {
1036 fn new(parent: Option<Module<'a>>,
1038 normal_ancestor_id: DefId,
1040 span: Span) -> Self {
1045 resolutions: RefCell::new(FxHashMap()),
1046 legacy_macro_resolutions: RefCell::new(Vec::new()),
1047 macro_resolutions: RefCell::new(Vec::new()),
1048 unresolved_invocations: RefCell::new(FxHashSet()),
1049 no_implicit_prelude: false,
1050 glob_importers: RefCell::new(Vec::new()),
1051 globs: RefCell::new(Vec::new()),
1052 traits: RefCell::new(None),
1053 populated: Cell::new(normal_ancestor_id.is_local()),
1059 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1060 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1061 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1065 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1066 let resolutions = self.resolutions.borrow();
1067 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1068 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1069 for &(&(ident, ns), &resolution) in resolutions.iter() {
1070 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1074 fn def(&self) -> Option<Def> {
1076 ModuleKind::Def(def, _) => Some(def),
1081 fn def_id(&self) -> Option<DefId> {
1082 self.def().as_ref().map(Def::def_id)
1085 // `self` resolves to the first module ancestor that `is_normal`.
1086 fn is_normal(&self) -> bool {
1088 ModuleKind::Def(Def::Mod(_), _) => true,
1093 fn is_trait(&self) -> bool {
1095 ModuleKind::Def(Def::Trait(_), _) => true,
1100 fn is_local(&self) -> bool {
1101 self.normal_ancestor_id.is_local()
1104 fn nearest_item_scope(&'a self) -> Module<'a> {
1105 if self.is_trait() { self.parent.unwrap() } else { self }
1109 impl<'a> fmt::Debug for ModuleData<'a> {
1110 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1111 write!(f, "{:?}", self.def())
1115 /// Records a possibly-private value, type, or module definition.
1116 #[derive(Clone, Debug)]
1117 pub struct NameBinding<'a> {
1118 kind: NameBindingKind<'a>,
1121 vis: ty::Visibility,
1124 pub trait ToNameBinding<'a> {
1125 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1128 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1129 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1134 #[derive(Clone, Debug)]
1135 enum NameBindingKind<'a> {
1136 Def(Def, /* is_macro_export */ bool),
1139 binding: &'a NameBinding<'a>,
1140 directive: &'a ImportDirective<'a>,
1144 b1: &'a NameBinding<'a>,
1145 b2: &'a NameBinding<'a>,
1149 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1151 struct UseError<'a> {
1152 err: DiagnosticBuilder<'a>,
1153 /// Attach `use` statements for these candidates
1154 candidates: Vec<ImportSuggestion>,
1155 /// The node id of the module to place the use statements in
1157 /// Whether the diagnostic should state that it's "better"
1161 struct AmbiguityError<'a> {
1165 b1: &'a NameBinding<'a>,
1166 b2: &'a NameBinding<'a>,
1169 impl<'a> NameBinding<'a> {
1170 fn module(&self) -> Option<Module<'a>> {
1172 NameBindingKind::Module(module) => Some(module),
1173 NameBindingKind::Import { binding, .. } => binding.module(),
1178 fn def(&self) -> Def {
1180 NameBindingKind::Def(def, _) => def,
1181 NameBindingKind::Module(module) => module.def().unwrap(),
1182 NameBindingKind::Import { binding, .. } => binding.def(),
1183 NameBindingKind::Ambiguity { .. } => Def::Err,
1187 fn def_ignoring_ambiguity(&self) -> Def {
1189 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1190 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1195 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1196 resolver.get_macro(self.def_ignoring_ambiguity())
1199 // We sometimes need to treat variants as `pub` for backwards compatibility
1200 fn pseudo_vis(&self) -> ty::Visibility {
1201 if self.is_variant() && self.def().def_id().is_local() {
1202 ty::Visibility::Public
1208 fn is_variant(&self) -> bool {
1210 NameBindingKind::Def(Def::Variant(..), _) |
1211 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1216 fn is_extern_crate(&self) -> bool {
1218 NameBindingKind::Import {
1219 directive: &ImportDirective {
1220 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1227 fn is_import(&self) -> bool {
1229 NameBindingKind::Import { .. } => true,
1234 fn is_renamed_extern_crate(&self) -> bool {
1235 if let NameBindingKind::Import { directive, ..} = self.kind {
1236 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1243 fn is_glob_import(&self) -> bool {
1245 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1246 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1251 fn is_importable(&self) -> bool {
1253 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1258 fn is_macro_def(&self) -> bool {
1260 NameBindingKind::Def(Def::Macro(..), _) => true,
1265 fn descr(&self) -> &'static str {
1266 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1270 /// Interns the names of the primitive types.
1272 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1273 /// special handling, since they have no place of origin.
1274 struct PrimitiveTypeTable {
1275 primitive_types: FxHashMap<Name, PrimTy>,
1278 impl PrimitiveTypeTable {
1279 fn new() -> PrimitiveTypeTable {
1280 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1282 table.intern("bool", TyBool);
1283 table.intern("char", TyChar);
1284 table.intern("f32", TyFloat(FloatTy::F32));
1285 table.intern("f64", TyFloat(FloatTy::F64));
1286 table.intern("isize", TyInt(IntTy::Isize));
1287 table.intern("i8", TyInt(IntTy::I8));
1288 table.intern("i16", TyInt(IntTy::I16));
1289 table.intern("i32", TyInt(IntTy::I32));
1290 table.intern("i64", TyInt(IntTy::I64));
1291 table.intern("i128", TyInt(IntTy::I128));
1292 table.intern("str", TyStr);
1293 table.intern("usize", TyUint(UintTy::Usize));
1294 table.intern("u8", TyUint(UintTy::U8));
1295 table.intern("u16", TyUint(UintTy::U16));
1296 table.intern("u32", TyUint(UintTy::U32));
1297 table.intern("u64", TyUint(UintTy::U64));
1298 table.intern("u128", TyUint(UintTy::U128));
1302 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1303 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1307 /// The main resolver class.
1309 /// This is the visitor that walks the whole crate.
1310 pub struct Resolver<'a, 'b: 'a> {
1311 session: &'a Session,
1314 pub definitions: Definitions,
1316 graph_root: Module<'a>,
1318 prelude: Option<Module<'a>>,
1319 extern_prelude: FxHashSet<Name>,
1321 /// n.b. This is used only for better diagnostics, not name resolution itself.
1322 has_self: FxHashSet<DefId>,
1324 /// Names of fields of an item `DefId` accessible with dot syntax.
1325 /// Used for hints during error reporting.
1326 field_names: FxHashMap<DefId, Vec<Name>>,
1328 /// All imports known to succeed or fail.
1329 determined_imports: Vec<&'a ImportDirective<'a>>,
1331 /// All non-determined imports.
1332 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1334 /// The module that represents the current item scope.
1335 current_module: Module<'a>,
1337 /// The current set of local scopes for types and values.
1338 /// FIXME #4948: Reuse ribs to avoid allocation.
1339 ribs: PerNS<Vec<Rib<'a>>>,
1341 /// The current set of local scopes, for labels.
1342 label_ribs: Vec<Rib<'a>>,
1344 /// The trait that the current context can refer to.
1345 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1347 /// The current self type if inside an impl (used for better errors).
1348 current_self_type: Option<Ty>,
1350 /// The idents for the primitive types.
1351 primitive_type_table: PrimitiveTypeTable,
1354 import_map: ImportMap,
1355 pub freevars: FreevarMap,
1356 freevars_seen: NodeMap<NodeMap<usize>>,
1357 pub export_map: ExportMap,
1358 pub trait_map: TraitMap,
1360 /// A map from nodes to anonymous modules.
1361 /// Anonymous modules are pseudo-modules that are implicitly created around items
1362 /// contained within blocks.
1364 /// For example, if we have this:
1372 /// There will be an anonymous module created around `g` with the ID of the
1373 /// entry block for `f`.
1374 block_map: NodeMap<Module<'a>>,
1375 module_map: FxHashMap<DefId, Module<'a>>,
1376 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1378 pub make_glob_map: bool,
1379 /// Maps imports to the names of items actually imported (this actually maps
1380 /// all imports, but only glob imports are actually interesting).
1381 pub glob_map: GlobMap,
1383 used_imports: FxHashSet<(NodeId, Namespace)>,
1384 pub maybe_unused_trait_imports: NodeSet,
1385 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1387 /// A list of labels as of yet unused. Labels will be removed from this map when
1388 /// they are used (in a `break` or `continue` statement)
1389 pub unused_labels: FxHashMap<NodeId, Span>,
1391 /// privacy errors are delayed until the end in order to deduplicate them
1392 privacy_errors: Vec<PrivacyError<'a>>,
1393 /// ambiguity errors are delayed for deduplication
1394 ambiguity_errors: Vec<AmbiguityError<'a>>,
1395 /// `use` injections are delayed for better placement and deduplication
1396 use_injections: Vec<UseError<'a>>,
1397 /// `use` injections for proc macros wrongly imported with #[macro_use]
1398 proc_mac_errors: Vec<macros::ProcMacError>,
1399 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1400 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1402 gated_errors: FxHashSet<Span>,
1403 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1405 arenas: &'a ResolverArenas<'a>,
1406 dummy_binding: &'a NameBinding<'a>,
1407 /// true if `#![feature(use_extern_macros)]`
1408 use_extern_macros: bool,
1410 crate_loader: &'a mut CrateLoader<'b>,
1411 macro_names: FxHashSet<Ident>,
1412 macro_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1413 pub all_macros: FxHashMap<Name, Def>,
1414 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1415 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1416 macro_defs: FxHashMap<Mark, DefId>,
1417 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1418 macro_exports: Vec<Export>, // FIXME: Remove when `use_extern_macros` is stabilized
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 features = session.features_untracked();
1662 let mut macro_defs = FxHashMap();
1663 macro_defs.insert(Mark::root(), root_def_id);
1672 // The outermost module has def ID 0; this is not reflected in the
1678 has_self: FxHashSet(),
1679 field_names: FxHashMap(),
1681 determined_imports: Vec::new(),
1682 indeterminate_imports: Vec::new(),
1684 current_module: graph_root,
1686 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1687 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1688 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1690 label_ribs: Vec::new(),
1692 current_trait_ref: None,
1693 current_self_type: None,
1695 primitive_type_table: PrimitiveTypeTable::new(),
1698 import_map: NodeMap(),
1699 freevars: NodeMap(),
1700 freevars_seen: NodeMap(),
1701 export_map: FxHashMap(),
1702 trait_map: NodeMap(),
1704 block_map: NodeMap(),
1705 extern_module_map: FxHashMap(),
1707 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1708 glob_map: NodeMap(),
1710 used_imports: FxHashSet(),
1711 maybe_unused_trait_imports: NodeSet(),
1712 maybe_unused_extern_crates: Vec::new(),
1714 unused_labels: FxHashMap(),
1716 privacy_errors: Vec::new(),
1717 ambiguity_errors: Vec::new(),
1718 use_injections: Vec::new(),
1719 proc_mac_errors: Vec::new(),
1720 gated_errors: FxHashSet(),
1721 disallowed_shadowing: Vec::new(),
1722 macro_expanded_macro_export_errors: BTreeSet::new(),
1725 dummy_binding: arenas.alloc_name_binding(NameBinding {
1726 kind: NameBindingKind::Def(Def::Err, false),
1727 expansion: Mark::root(),
1729 vis: ty::Visibility::Public,
1732 use_extern_macros: features.use_extern_macros(),
1735 macro_names: FxHashSet(),
1736 macro_prelude: FxHashMap(),
1737 all_macros: FxHashMap(),
1738 lexical_macro_resolutions: Vec::new(),
1739 macro_map: FxHashMap(),
1740 macro_exports: Vec::new(),
1743 local_macro_def_scopes: FxHashMap(),
1744 name_already_seen: FxHashMap(),
1745 whitelisted_legacy_custom_derives: Vec::new(),
1746 warned_proc_macros: FxHashSet(),
1747 potentially_unused_imports: Vec::new(),
1748 struct_constructors: DefIdMap(),
1749 found_unresolved_macro: false,
1750 unused_macros: FxHashSet(),
1751 current_type_ascription: Vec::new(),
1752 injected_crate: None,
1753 ignore_extern_prelude_feature: false,
1757 pub fn arenas() -> ResolverArenas<'a> {
1759 modules: arena::TypedArena::new(),
1760 local_modules: RefCell::new(Vec::new()),
1761 name_bindings: arena::TypedArena::new(),
1762 import_directives: arena::TypedArena::new(),
1763 name_resolutions: arena::TypedArena::new(),
1764 invocation_data: arena::TypedArena::new(),
1765 legacy_bindings: arena::TypedArena::new(),
1769 /// Runs the function on each namespace.
1770 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1773 if self.use_extern_macros {
1778 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1780 match self.macro_defs.get(&ctxt.outer()) {
1781 Some(&def_id) => return def_id,
1782 None => ctxt.remove_mark(),
1787 /// Entry point to crate resolution.
1788 pub fn resolve_crate(&mut self, krate: &Crate) {
1789 ImportResolver { resolver: self }.finalize_imports();
1790 self.current_module = self.graph_root;
1791 self.finalize_current_module_macro_resolutions();
1793 visit::walk_crate(self, krate);
1795 check_unused::check_crate(self, krate);
1796 self.report_errors(krate);
1797 self.crate_loader.postprocess(krate);
1804 normal_ancestor_id: DefId,
1808 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1809 self.arenas.alloc_module(module)
1812 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1813 -> bool /* true if an error was reported */ {
1814 match binding.kind {
1815 NameBindingKind::Import { directive, binding, ref used }
1818 directive.used.set(true);
1819 self.used_imports.insert((directive.id, ns));
1820 self.add_to_glob_map(directive.id, ident);
1821 self.record_use(ident, ns, binding, span)
1823 NameBindingKind::Import { .. } => false,
1824 NameBindingKind::Ambiguity { b1, b2 } => {
1825 self.ambiguity_errors.push(AmbiguityError {
1826 span, name: ident.name, lexical: false, b1, b2,
1834 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1835 if self.make_glob_map {
1836 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1840 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1841 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1842 /// `ident` in the first scope that defines it (or None if no scopes define it).
1844 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1845 /// the items are defined in the block. For example,
1848 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1851 /// g(); // This resolves to the local variable `g` since it shadows the item.
1855 /// Invariant: This must only be called during main resolution, not during
1856 /// import resolution.
1857 fn resolve_ident_in_lexical_scope(&mut self,
1860 record_used_id: Option<NodeId>,
1862 -> Option<LexicalScopeBinding<'a>> {
1863 let record_used = record_used_id.is_some();
1864 assert!(ns == TypeNS || ns == ValueNS);
1866 ident.span = if ident.name == keywords::SelfType.name() {
1867 // FIXME(jseyfried) improve `Self` hygiene
1868 ident.span.with_ctxt(SyntaxContext::empty())
1873 ident = ident.modern_and_legacy();
1876 // Walk backwards up the ribs in scope.
1877 let mut module = self.graph_root;
1878 for i in (0 .. self.ribs[ns].len()).rev() {
1879 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1880 // The ident resolves to a type parameter or local variable.
1881 return Some(LexicalScopeBinding::Def(
1882 self.adjust_local_def(ns, i, def, record_used, path_span)
1886 module = match self.ribs[ns][i].kind {
1887 ModuleRibKind(module) => module,
1888 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1889 // If an invocation of this macro created `ident`, give up on `ident`
1890 // and switch to `ident`'s source from the macro definition.
1891 ident.span.remove_mark();
1897 let item = self.resolve_ident_in_module_unadjusted(
1898 ModuleOrUniformRoot::Module(module),
1905 if let Ok(binding) = item {
1906 // The ident resolves to an item.
1907 return Some(LexicalScopeBinding::Item(binding));
1911 ModuleKind::Block(..) => {}, // We can see through blocks
1916 ident.span = ident.span.modern();
1918 let (opt_module, poisoned) = if let Some(node_id) = record_used_id {
1919 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1922 (self.hygienic_lexical_parent(module, &mut ident.span), None)
1924 module = unwrap_or!(opt_module, break);
1925 let orig_current_module = self.current_module;
1926 self.current_module = module; // Lexical resolutions can never be a privacy error.
1927 let result = self.resolve_ident_in_module_unadjusted(
1928 ModuleOrUniformRoot::Module(module),
1935 self.current_module = orig_current_module;
1939 if let Some(node_id) = poisoned {
1940 self.session.buffer_lint_with_diagnostic(
1941 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1942 node_id, ident.span,
1943 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1944 lint::builtin::BuiltinLintDiagnostics::
1945 ProcMacroDeriveResolutionFallback(ident.span),
1948 return Some(LexicalScopeBinding::Item(binding))
1950 _ if poisoned.is_some() => break,
1951 Err(Determined) => continue,
1952 Err(Undetermined) =>
1953 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1957 if !module.no_implicit_prelude {
1958 // `record_used` means that we don't try to load crates during speculative resolution
1959 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1960 if !self.session.features_untracked().extern_prelude &&
1961 !self.ignore_extern_prelude_feature {
1962 feature_err(&self.session.parse_sess, "extern_prelude",
1963 ident.span, GateIssue::Language,
1964 "access to extern crates through prelude is experimental").emit();
1967 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1968 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1969 self.populate_module_if_necessary(crate_root);
1971 let binding = (crate_root, ty::Visibility::Public,
1972 ident.span, Mark::root()).to_name_binding(self.arenas);
1973 return Some(LexicalScopeBinding::Item(binding));
1975 if ns == TypeNS && is_known_tool(ident.name) {
1976 let binding = (Def::ToolMod, ty::Visibility::Public,
1977 ident.span, Mark::root()).to_name_binding(self.arenas);
1978 return Some(LexicalScopeBinding::Item(binding));
1980 if let Some(prelude) = self.prelude {
1981 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1982 ModuleOrUniformRoot::Module(prelude),
1989 return Some(LexicalScopeBinding::Item(binding));
1997 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
1998 -> Option<Module<'a>> {
1999 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2000 return Some(self.macro_def_scope(span.remove_mark()));
2003 if let ModuleKind::Block(..) = module.kind {
2004 return Some(module.parent.unwrap());
2010 fn hygienic_lexical_parent_with_compatibility_fallback(
2011 &mut self, module: Module<'a>, span: &mut Span, node_id: NodeId
2012 ) -> (Option<Module<'a>>, /* poisoned */ Option<NodeId>)
2014 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2015 return (module, None);
2018 // We need to support the next case under a deprecation warning
2021 // ---- begin: this comes from a proc macro derive
2022 // mod implementation_details {
2023 // // Note that `MyStruct` is not in scope here.
2024 // impl SomeTrait for MyStruct { ... }
2028 // So we have to fall back to the module's parent during lexical resolution in this case.
2029 if let Some(parent) = module.parent {
2030 // Inner module is inside the macro, parent module is outside of the macro.
2031 if module.expansion != parent.expansion &&
2032 module.expansion.is_descendant_of(parent.expansion) {
2033 // The macro is a proc macro derive
2034 if module.expansion.looks_like_proc_macro_derive() {
2035 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2036 return (module.parent, Some(node_id));
2045 fn resolve_ident_in_module(&mut self,
2046 module: ModuleOrUniformRoot<'a>,
2051 -> Result<&'a NameBinding<'a>, Determinacy> {
2052 ident.span = ident.span.modern();
2053 let orig_current_module = self.current_module;
2054 if let ModuleOrUniformRoot::Module(module) = module {
2055 if let Some(def) = ident.span.adjust(module.expansion) {
2056 self.current_module = self.macro_def_scope(def);
2059 let result = self.resolve_ident_in_module_unadjusted(
2060 module, ident, ns, false, record_used, span,
2062 self.current_module = orig_current_module;
2066 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2067 let mut ctxt = ident.span.ctxt();
2068 let mark = if ident.name == keywords::DollarCrate.name() {
2069 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2070 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2071 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2072 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2073 // definitions actually produced by `macro` and `macro` definitions produced by
2074 // `macro_rules!`, but at least such configurations are not stable yet.
2075 ctxt = ctxt.modern_and_legacy();
2076 let mut iter = ctxt.marks().into_iter().rev().peekable();
2077 let mut result = None;
2078 // Find the last modern mark from the end if it exists.
2079 while let Some(&(mark, transparency)) = iter.peek() {
2080 if transparency == Transparency::Opaque {
2081 result = Some(mark);
2087 // Then find the last legacy mark from the end if it exists.
2088 for (mark, transparency) in iter {
2089 if transparency == Transparency::SemiTransparent {
2090 result = Some(mark);
2097 ctxt = ctxt.modern();
2098 ctxt.adjust(Mark::root())
2100 let module = match mark {
2101 Some(def) => self.macro_def_scope(def),
2102 None => return self.graph_root,
2104 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2107 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2108 let mut module = self.get_module(module.normal_ancestor_id);
2109 while module.span.ctxt().modern() != *ctxt {
2110 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2111 module = self.get_module(parent.normal_ancestor_id);
2118 // We maintain a list of value ribs and type ribs.
2120 // Simultaneously, we keep track of the current position in the module
2121 // graph in the `current_module` pointer. When we go to resolve a name in
2122 // the value or type namespaces, we first look through all the ribs and
2123 // then query the module graph. When we resolve a name in the module
2124 // namespace, we can skip all the ribs (since nested modules are not
2125 // allowed within blocks in Rust) and jump straight to the current module
2128 // Named implementations are handled separately. When we find a method
2129 // call, we consult the module node to find all of the implementations in
2130 // scope. This information is lazily cached in the module node. We then
2131 // generate a fake "implementation scope" containing all the
2132 // implementations thus found, for compatibility with old resolve pass.
2134 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2135 where F: FnOnce(&mut Resolver) -> T
2137 let id = self.definitions.local_def_id(id);
2138 let module = self.module_map.get(&id).cloned(); // clones a reference
2139 if let Some(module) = module {
2140 // Move down in the graph.
2141 let orig_module = replace(&mut self.current_module, module);
2142 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2143 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2145 self.finalize_current_module_macro_resolutions();
2148 self.current_module = orig_module;
2149 self.ribs[ValueNS].pop();
2150 self.ribs[TypeNS].pop();
2157 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2158 /// is returned by the given predicate function
2160 /// Stops after meeting a closure.
2161 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2162 where P: Fn(&Rib, Ident) -> Option<R>
2164 for rib in self.label_ribs.iter().rev() {
2167 // If an invocation of this macro created `ident`, give up on `ident`
2168 // and switch to `ident`'s source from the macro definition.
2169 MacroDefinition(def) => {
2170 if def == self.macro_def(ident.span.ctxt()) {
2171 ident.span.remove_mark();
2175 // Do not resolve labels across function boundary
2179 let r = pred(rib, ident);
2187 fn resolve_item(&mut self, item: &Item) {
2188 let name = item.ident.name;
2190 debug!("(resolving item) resolving {}", name);
2192 self.check_proc_macro_attrs(&item.attrs);
2195 ItemKind::Enum(_, ref generics) |
2196 ItemKind::Ty(_, ref generics) |
2197 ItemKind::Existential(_, ref generics) |
2198 ItemKind::Struct(_, ref generics) |
2199 ItemKind::Union(_, ref generics) |
2200 ItemKind::Fn(_, _, ref generics, _) => {
2201 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2202 |this| visit::walk_item(this, item));
2205 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2206 self.resolve_implementation(generics,
2212 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2213 // Create a new rib for the trait-wide type parameters.
2214 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2215 let local_def_id = this.definitions.local_def_id(item.id);
2216 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2217 this.visit_generics(generics);
2218 walk_list!(this, visit_param_bound, bounds);
2220 for trait_item in trait_items {
2221 this.check_proc_macro_attrs(&trait_item.attrs);
2223 let type_parameters = HasTypeParameters(&trait_item.generics,
2224 TraitOrImplItemRibKind);
2225 this.with_type_parameter_rib(type_parameters, |this| {
2226 match trait_item.node {
2227 TraitItemKind::Const(ref ty, ref default) => {
2230 // Only impose the restrictions of
2231 // ConstRibKind for an actual constant
2232 // expression in a provided default.
2233 if let Some(ref expr) = *default{
2234 this.with_constant_rib(|this| {
2235 this.visit_expr(expr);
2239 TraitItemKind::Method(_, _) => {
2240 visit::walk_trait_item(this, trait_item)
2242 TraitItemKind::Type(..) => {
2243 visit::walk_trait_item(this, trait_item)
2245 TraitItemKind::Macro(_) => {
2246 panic!("unexpanded macro in resolve!")
2255 ItemKind::TraitAlias(ref generics, ref bounds) => {
2256 // Create a new rib for the trait-wide type parameters.
2257 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2258 let local_def_id = this.definitions.local_def_id(item.id);
2259 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2260 this.visit_generics(generics);
2261 walk_list!(this, visit_param_bound, bounds);
2266 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2267 self.with_scope(item.id, |this| {
2268 visit::walk_item(this, item);
2272 ItemKind::Static(ref ty, _, ref expr) |
2273 ItemKind::Const(ref ty, ref expr) => {
2274 self.with_item_rib(|this| {
2276 this.with_constant_rib(|this| {
2277 this.visit_expr(expr);
2282 ItemKind::Use(ref use_tree) => {
2283 // Imports are resolved as global by default, add starting root segment.
2285 segments: use_tree.prefix.make_root().into_iter().collect(),
2286 span: use_tree.span,
2288 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2291 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2292 // do nothing, these are just around to be encoded
2295 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2299 /// For the most part, use trees are desugared into `ImportDirective` instances
2300 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2301 /// there is one special case we handle here: an empty nested import like
2302 /// `a::{b::{}}`, which desugares into...no import directives.
2303 fn resolve_use_tree(
2308 use_tree: &ast::UseTree,
2311 match use_tree.kind {
2312 ast::UseTreeKind::Nested(ref items) => {
2314 segments: prefix.segments
2316 .chain(use_tree.prefix.segments.iter())
2319 span: prefix.span.to(use_tree.prefix.span),
2322 if items.len() == 0 {
2323 // Resolve prefix of an import with empty braces (issue #28388).
2324 self.smart_resolve_path_with_crate_lint(
2328 PathSource::ImportPrefix,
2329 CrateLint::UsePath { root_id, root_span },
2332 for &(ref tree, nested_id) in items {
2333 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2337 ast::UseTreeKind::Simple(..) => {},
2338 ast::UseTreeKind::Glob => {},
2342 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2343 where F: FnOnce(&mut Resolver)
2345 match type_parameters {
2346 HasTypeParameters(generics, rib_kind) => {
2347 let mut function_type_rib = Rib::new(rib_kind);
2348 let mut seen_bindings = FxHashMap();
2349 generics.params.iter().for_each(|param| match param.kind {
2350 GenericParamKind::Lifetime { .. } => {}
2351 GenericParamKind::Type { .. } => {
2352 let ident = param.ident.modern();
2353 debug!("with_type_parameter_rib: {}", param.id);
2355 if seen_bindings.contains_key(&ident) {
2356 let span = seen_bindings.get(&ident).unwrap();
2357 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2361 resolve_error(self, param.ident.span, err);
2363 seen_bindings.entry(ident).or_insert(param.ident.span);
2365 // Plain insert (no renaming).
2366 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2367 function_type_rib.bindings.insert(ident, def);
2368 self.record_def(param.id, PathResolution::new(def));
2371 self.ribs[TypeNS].push(function_type_rib);
2374 NoTypeParameters => {
2381 if let HasTypeParameters(..) = type_parameters {
2382 self.ribs[TypeNS].pop();
2386 fn with_label_rib<F>(&mut self, f: F)
2387 where F: FnOnce(&mut Resolver)
2389 self.label_ribs.push(Rib::new(NormalRibKind));
2391 self.label_ribs.pop();
2394 fn with_item_rib<F>(&mut self, f: F)
2395 where F: FnOnce(&mut Resolver)
2397 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2398 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2400 self.ribs[TypeNS].pop();
2401 self.ribs[ValueNS].pop();
2404 fn with_constant_rib<F>(&mut self, f: F)
2405 where F: FnOnce(&mut Resolver)
2407 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2408 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2410 self.label_ribs.pop();
2411 self.ribs[ValueNS].pop();
2414 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2415 where F: FnOnce(&mut Resolver) -> T
2417 // Handle nested impls (inside fn bodies)
2418 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2419 let result = f(self);
2420 self.current_self_type = previous_value;
2424 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2425 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2426 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2428 let mut new_val = None;
2429 let mut new_id = None;
2430 if let Some(trait_ref) = opt_trait_ref {
2431 let path: Vec<_> = trait_ref.path.segments.iter()
2432 .map(|seg| seg.ident)
2434 let def = self.smart_resolve_path_fragment(
2438 trait_ref.path.span,
2439 PathSource::Trait(AliasPossibility::No),
2440 CrateLint::SimplePath(trait_ref.ref_id),
2442 if def != Def::Err {
2443 new_id = Some(def.def_id());
2444 let span = trait_ref.path.span;
2445 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2452 CrateLint::SimplePath(trait_ref.ref_id),
2455 new_val = Some((module, trait_ref.clone()));
2459 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2460 let result = f(self, new_id);
2461 self.current_trait_ref = original_trait_ref;
2465 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2466 where F: FnOnce(&mut Resolver)
2468 let mut self_type_rib = Rib::new(NormalRibKind);
2470 // plain insert (no renaming, types are not currently hygienic....)
2471 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2472 self.ribs[TypeNS].push(self_type_rib);
2474 self.ribs[TypeNS].pop();
2477 fn resolve_implementation(&mut self,
2478 generics: &Generics,
2479 opt_trait_reference: &Option<TraitRef>,
2482 impl_items: &[ImplItem]) {
2483 // If applicable, create a rib for the type parameters.
2484 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2485 // Dummy self type for better errors if `Self` is used in the trait path.
2486 this.with_self_rib(Def::SelfTy(None, None), |this| {
2487 // Resolve the trait reference, if necessary.
2488 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2489 let item_def_id = this.definitions.local_def_id(item_id);
2490 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2491 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2492 // Resolve type arguments in trait path
2493 visit::walk_trait_ref(this, trait_ref);
2495 // Resolve the self type.
2496 this.visit_ty(self_type);
2497 // Resolve the type parameters.
2498 this.visit_generics(generics);
2499 this.with_current_self_type(self_type, |this| {
2500 for impl_item in impl_items {
2501 this.check_proc_macro_attrs(&impl_item.attrs);
2502 this.resolve_visibility(&impl_item.vis);
2504 // We also need a new scope for the impl item type parameters.
2505 let type_parameters = HasTypeParameters(&impl_item.generics,
2506 TraitOrImplItemRibKind);
2507 this.with_type_parameter_rib(type_parameters, |this| {
2508 use self::ResolutionError::*;
2509 match impl_item.node {
2510 ImplItemKind::Const(..) => {
2511 // If this is a trait impl, ensure the const
2513 this.check_trait_item(impl_item.ident,
2516 |n, s| ConstNotMemberOfTrait(n, s));
2517 this.with_constant_rib(|this|
2518 visit::walk_impl_item(this, impl_item)
2521 ImplItemKind::Method(..) => {
2522 // If this is a trait impl, ensure the method
2524 this.check_trait_item(impl_item.ident,
2527 |n, s| MethodNotMemberOfTrait(n, s));
2529 visit::walk_impl_item(this, impl_item);
2531 ImplItemKind::Type(ref ty) => {
2532 // If this is a trait impl, ensure the type
2534 this.check_trait_item(impl_item.ident,
2537 |n, s| TypeNotMemberOfTrait(n, s));
2541 ImplItemKind::Existential(ref bounds) => {
2542 // If this is a trait impl, ensure the type
2544 this.check_trait_item(impl_item.ident,
2547 |n, s| TypeNotMemberOfTrait(n, s));
2549 for bound in bounds {
2550 this.visit_param_bound(bound);
2553 ImplItemKind::Macro(_) =>
2554 panic!("unexpanded macro in resolve!"),
2565 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2566 where F: FnOnce(Name, &str) -> ResolutionError
2568 // If there is a TraitRef in scope for an impl, then the method must be in the
2570 if let Some((module, _)) = self.current_trait_ref {
2571 if self.resolve_ident_in_module(
2572 ModuleOrUniformRoot::Module(module),
2578 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2579 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2584 fn resolve_local(&mut self, local: &Local) {
2585 // Resolve the type.
2586 walk_list!(self, visit_ty, &local.ty);
2588 // Resolve the initializer.
2589 walk_list!(self, visit_expr, &local.init);
2591 // Resolve the pattern.
2592 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2595 // build a map from pattern identifiers to binding-info's.
2596 // this is done hygienically. This could arise for a macro
2597 // that expands into an or-pattern where one 'x' was from the
2598 // user and one 'x' came from the macro.
2599 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2600 let mut binding_map = FxHashMap();
2602 pat.walk(&mut |pat| {
2603 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2604 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2605 Some(Def::Local(..)) => true,
2608 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2609 binding_map.insert(ident, binding_info);
2618 // check that all of the arms in an or-pattern have exactly the
2619 // same set of bindings, with the same binding modes for each.
2620 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2621 if pats.is_empty() {
2625 let mut missing_vars = FxHashMap();
2626 let mut inconsistent_vars = FxHashMap();
2627 for (i, p) in pats.iter().enumerate() {
2628 let map_i = self.binding_mode_map(&p);
2630 for (j, q) in pats.iter().enumerate() {
2635 let map_j = self.binding_mode_map(&q);
2636 for (&key, &binding_i) in &map_i {
2637 if map_j.len() == 0 { // Account for missing bindings when
2638 let binding_error = missing_vars // map_j has none.
2640 .or_insert(BindingError {
2642 origin: BTreeSet::new(),
2643 target: BTreeSet::new(),
2645 binding_error.origin.insert(binding_i.span);
2646 binding_error.target.insert(q.span);
2648 for (&key_j, &binding_j) in &map_j {
2649 match map_i.get(&key_j) {
2650 None => { // missing binding
2651 let binding_error = missing_vars
2653 .or_insert(BindingError {
2655 origin: BTreeSet::new(),
2656 target: BTreeSet::new(),
2658 binding_error.origin.insert(binding_j.span);
2659 binding_error.target.insert(p.span);
2661 Some(binding_i) => { // check consistent binding
2662 if binding_i.binding_mode != binding_j.binding_mode {
2665 .or_insert((binding_j.span, binding_i.span));
2673 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2674 missing_vars.sort();
2675 for (_, v) in missing_vars {
2677 *v.origin.iter().next().unwrap(),
2678 ResolutionError::VariableNotBoundInPattern(v));
2680 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2681 inconsistent_vars.sort();
2682 for (name, v) in inconsistent_vars {
2683 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2687 fn resolve_arm(&mut self, arm: &Arm) {
2688 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2690 let mut bindings_list = FxHashMap();
2691 for pattern in &arm.pats {
2692 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2695 // This has to happen *after* we determine which pat_idents are variants
2696 self.check_consistent_bindings(&arm.pats);
2698 walk_list!(self, visit_expr, &arm.guard);
2699 self.visit_expr(&arm.body);
2701 self.ribs[ValueNS].pop();
2704 fn resolve_block(&mut self, block: &Block) {
2705 debug!("(resolving block) entering block");
2706 // Move down in the graph, if there's an anonymous module rooted here.
2707 let orig_module = self.current_module;
2708 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2710 let mut num_macro_definition_ribs = 0;
2711 if let Some(anonymous_module) = anonymous_module {
2712 debug!("(resolving block) found anonymous module, moving down");
2713 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2714 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2715 self.current_module = anonymous_module;
2716 self.finalize_current_module_macro_resolutions();
2718 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2721 // Descend into the block.
2722 for stmt in &block.stmts {
2723 if let ast::StmtKind::Item(ref item) = stmt.node {
2724 if let ast::ItemKind::MacroDef(..) = item.node {
2725 num_macro_definition_ribs += 1;
2726 let def = self.definitions.local_def_id(item.id);
2727 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2728 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2732 self.visit_stmt(stmt);
2736 self.current_module = orig_module;
2737 for _ in 0 .. num_macro_definition_ribs {
2738 self.ribs[ValueNS].pop();
2739 self.label_ribs.pop();
2741 self.ribs[ValueNS].pop();
2742 if anonymous_module.is_some() {
2743 self.ribs[TypeNS].pop();
2745 debug!("(resolving block) leaving block");
2748 fn fresh_binding(&mut self,
2751 outer_pat_id: NodeId,
2752 pat_src: PatternSource,
2753 bindings: &mut FxHashMap<Ident, NodeId>)
2755 // Add the binding to the local ribs, if it
2756 // doesn't already exist in the bindings map. (We
2757 // must not add it if it's in the bindings map
2758 // because that breaks the assumptions later
2759 // passes make about or-patterns.)
2760 let ident = ident.modern_and_legacy();
2761 let mut def = Def::Local(pat_id);
2762 match bindings.get(&ident).cloned() {
2763 Some(id) if id == outer_pat_id => {
2764 // `Variant(a, a)`, error
2768 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2772 Some(..) if pat_src == PatternSource::FnParam => {
2773 // `fn f(a: u8, a: u8)`, error
2777 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2781 Some(..) if pat_src == PatternSource::Match ||
2782 pat_src == PatternSource::IfLet ||
2783 pat_src == PatternSource::WhileLet => {
2784 // `Variant1(a) | Variant2(a)`, ok
2785 // Reuse definition from the first `a`.
2786 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2789 span_bug!(ident.span, "two bindings with the same name from \
2790 unexpected pattern source {:?}", pat_src);
2793 // A completely fresh binding, add to the lists if it's valid.
2794 if ident.name != keywords::Invalid.name() {
2795 bindings.insert(ident, outer_pat_id);
2796 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2801 PathResolution::new(def)
2804 fn resolve_pattern(&mut self,
2806 pat_src: PatternSource,
2807 // Maps idents to the node ID for the
2808 // outermost pattern that binds them.
2809 bindings: &mut FxHashMap<Ident, NodeId>) {
2810 // Visit all direct subpatterns of this pattern.
2811 let outer_pat_id = pat.id;
2812 pat.walk(&mut |pat| {
2814 PatKind::Ident(bmode, ident, ref opt_pat) => {
2815 // First try to resolve the identifier as some existing
2816 // entity, then fall back to a fresh binding.
2817 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2819 .and_then(LexicalScopeBinding::item);
2820 let resolution = binding.map(NameBinding::def).and_then(|def| {
2821 let is_syntactic_ambiguity = opt_pat.is_none() &&
2822 bmode == BindingMode::ByValue(Mutability::Immutable);
2824 Def::StructCtor(_, CtorKind::Const) |
2825 Def::VariantCtor(_, CtorKind::Const) |
2826 Def::Const(..) if is_syntactic_ambiguity => {
2827 // Disambiguate in favor of a unit struct/variant
2828 // or constant pattern.
2829 self.record_use(ident, ValueNS, binding.unwrap(), ident.span);
2830 Some(PathResolution::new(def))
2832 Def::StructCtor(..) | Def::VariantCtor(..) |
2833 Def::Const(..) | Def::Static(..) => {
2834 // This is unambiguously a fresh binding, either syntactically
2835 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2836 // to something unusable as a pattern (e.g. constructor function),
2837 // but we still conservatively report an error, see
2838 // issues/33118#issuecomment-233962221 for one reason why.
2842 ResolutionError::BindingShadowsSomethingUnacceptable(
2843 pat_src.descr(), ident.name, binding.unwrap())
2847 Def::Fn(..) | Def::Err => {
2848 // These entities are explicitly allowed
2849 // to be shadowed by fresh bindings.
2853 span_bug!(ident.span, "unexpected definition for an \
2854 identifier in pattern: {:?}", def);
2857 }).unwrap_or_else(|| {
2858 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2861 self.record_def(pat.id, resolution);
2864 PatKind::TupleStruct(ref path, ..) => {
2865 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2868 PatKind::Path(ref qself, ref path) => {
2869 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2872 PatKind::Struct(ref path, ..) => {
2873 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2881 visit::walk_pat(self, pat);
2884 // High-level and context dependent path resolution routine.
2885 // Resolves the path and records the resolution into definition map.
2886 // If resolution fails tries several techniques to find likely
2887 // resolution candidates, suggest imports or other help, and report
2888 // errors in user friendly way.
2889 fn smart_resolve_path(&mut self,
2891 qself: Option<&QSelf>,
2895 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2898 /// A variant of `smart_resolve_path` where you also specify extra
2899 /// information about where the path came from; this extra info is
2900 /// sometimes needed for the lint that recommends rewriting
2901 /// absolute paths to `crate`, so that it knows how to frame the
2902 /// suggestion. If you are just resolving a path like `foo::bar`
2903 /// that appears...somewhere, though, then you just want
2904 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2905 /// already provides.
2906 fn smart_resolve_path_with_crate_lint(
2909 qself: Option<&QSelf>,
2912 crate_lint: CrateLint
2913 ) -> PathResolution {
2914 let segments = &path.segments.iter()
2915 .map(|seg| seg.ident)
2916 .collect::<Vec<_>>();
2917 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2920 fn smart_resolve_path_fragment(&mut self,
2922 qself: Option<&QSelf>,
2926 crate_lint: CrateLint)
2928 let ident_span = path.last().map_or(span, |ident| ident.span);
2929 let ns = source.namespace();
2930 let is_expected = &|def| source.is_expected(def);
2931 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2933 // Base error is amended with one short label and possibly some longer helps/notes.
2934 let report_errors = |this: &mut Self, def: Option<Def>| {
2935 // Make the base error.
2936 let expected = source.descr_expected();
2937 let path_str = names_to_string(path);
2938 let code = source.error_code(def.is_some());
2939 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2940 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2941 format!("not a {}", expected),
2944 let item_str = path[path.len() - 1];
2945 let item_span = path[path.len() - 1].span;
2946 let (mod_prefix, mod_str) = if path.len() == 1 {
2947 (String::new(), "this scope".to_string())
2948 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2949 (String::new(), "the crate root".to_string())
2951 let mod_path = &path[..path.len() - 1];
2952 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2953 false, span, CrateLint::No) {
2954 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
2957 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
2958 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2960 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2961 format!("not found in {}", mod_str),
2964 let code = DiagnosticId::Error(code.into());
2965 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2967 // Emit special messages for unresolved `Self` and `self`.
2968 if is_self_type(path, ns) {
2969 __diagnostic_used!(E0411);
2970 err.code(DiagnosticId::Error("E0411".into()));
2971 err.span_label(span, "`Self` is only available in traits and impls");
2972 return (err, Vec::new());
2974 if is_self_value(path, ns) {
2975 __diagnostic_used!(E0424);
2976 err.code(DiagnosticId::Error("E0424".into()));
2977 err.span_label(span, format!("`self` value is only available in \
2978 methods with `self` parameter"));
2979 return (err, Vec::new());
2982 // Try to lookup the name in more relaxed fashion for better error reporting.
2983 let ident = *path.last().unwrap();
2984 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2985 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2986 let enum_candidates =
2987 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
2988 let mut enum_candidates = enum_candidates.iter()
2989 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2990 enum_candidates.sort();
2991 for (sp, variant_path, enum_path) in enum_candidates {
2993 let msg = format!("there is an enum variant `{}`, \
2999 err.span_suggestion(span, "you can try using the variant's enum",
3004 if path.len() == 1 && this.self_type_is_available(span) {
3005 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3006 let self_is_available = this.self_value_is_available(path[0].span, span);
3008 AssocSuggestion::Field => {
3009 err.span_suggestion(span, "try",
3010 format!("self.{}", path_str));
3011 if !self_is_available {
3012 err.span_label(span, format!("`self` value is only available in \
3013 methods with `self` parameter"));
3016 AssocSuggestion::MethodWithSelf if self_is_available => {
3017 err.span_suggestion(span, "try",
3018 format!("self.{}", path_str));
3020 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3021 err.span_suggestion(span, "try",
3022 format!("Self::{}", path_str));
3025 return (err, candidates);
3029 let mut levenshtein_worked = false;
3032 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3033 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3034 levenshtein_worked = true;
3037 // Try context dependent help if relaxed lookup didn't work.
3038 if let Some(def) = def {
3039 match (def, source) {
3040 (Def::Macro(..), _) => {
3041 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3042 return (err, candidates);
3044 (Def::TyAlias(..), PathSource::Trait(_)) => {
3045 err.span_label(span, "type aliases cannot be used for traits");
3046 return (err, candidates);
3048 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3049 ExprKind::Field(_, ident) => {
3050 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3052 return (err, candidates);
3054 ExprKind::MethodCall(ref segment, ..) => {
3055 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3056 path_str, segment.ident));
3057 return (err, candidates);
3061 (Def::Enum(..), PathSource::TupleStruct)
3062 | (Def::Enum(..), PathSource::Expr(..)) => {
3063 if let Some(variants) = this.collect_enum_variants(def) {
3064 err.note(&format!("did you mean to use one \
3065 of the following variants?\n{}",
3067 .map(|suggestion| path_names_to_string(suggestion))
3068 .map(|suggestion| format!("- `{}`", suggestion))
3069 .collect::<Vec<_>>()
3073 err.note("did you mean to use one of the enum's variants?");
3075 return (err, candidates);
3077 (Def::Struct(def_id), _) if ns == ValueNS => {
3078 if let Some((ctor_def, ctor_vis))
3079 = this.struct_constructors.get(&def_id).cloned() {
3080 let accessible_ctor = this.is_accessible(ctor_vis);
3081 if is_expected(ctor_def) && !accessible_ctor {
3082 err.span_label(span, format!("constructor is not visible \
3083 here due to private fields"));
3086 // HACK(estebank): find a better way to figure out that this was a
3087 // parser issue where a struct literal is being used on an expression
3088 // where a brace being opened means a block is being started. Look
3089 // ahead for the next text to see if `span` is followed by a `{`.
3090 let cm = this.session.codemap();
3093 sp = cm.next_point(sp);
3094 match cm.span_to_snippet(sp) {
3095 Ok(ref snippet) => {
3096 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3103 let followed_by_brace = match cm.span_to_snippet(sp) {
3104 Ok(ref snippet) if snippet == "{" => true,
3107 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3110 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3115 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3119 return (err, candidates);
3121 (Def::Union(..), _) |
3122 (Def::Variant(..), _) |
3123 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3124 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3126 return (err, candidates);
3128 (Def::SelfTy(..), _) if ns == ValueNS => {
3129 err.span_label(span, fallback_label);
3130 err.note("can't use `Self` as a constructor, you must use the \
3131 implemented struct");
3132 return (err, candidates);
3134 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3135 err.note("can't use a type alias as a constructor");
3136 return (err, candidates);
3143 if !levenshtein_worked {
3144 err.span_label(base_span, fallback_label);
3145 this.type_ascription_suggestion(&mut err, base_span);
3149 let report_errors = |this: &mut Self, def: Option<Def>| {
3150 let (err, candidates) = report_errors(this, def);
3151 let def_id = this.current_module.normal_ancestor_id;
3152 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3153 let better = def.is_some();
3154 this.use_injections.push(UseError { err, candidates, node_id, better });
3155 err_path_resolution()
3158 let resolution = match self.resolve_qpath_anywhere(
3164 source.defer_to_typeck(),
3165 source.global_by_default(),
3168 Some(resolution) if resolution.unresolved_segments() == 0 => {
3169 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3172 // Add a temporary hack to smooth the transition to new struct ctor
3173 // visibility rules. See #38932 for more details.
3175 if let Def::Struct(def_id) = resolution.base_def() {
3176 if let Some((ctor_def, ctor_vis))
3177 = self.struct_constructors.get(&def_id).cloned() {
3178 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3179 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3180 self.session.buffer_lint(lint, id, span,
3181 "private struct constructors are not usable through \
3182 re-exports in outer modules",
3184 res = Some(PathResolution::new(ctor_def));
3189 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3192 Some(resolution) if source.defer_to_typeck() => {
3193 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3194 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3195 // it needs to be added to the trait map.
3197 let item_name = *path.last().unwrap();
3198 let traits = self.get_traits_containing_item(item_name, ns);
3199 self.trait_map.insert(id, traits);
3203 _ => report_errors(self, None)
3206 if let PathSource::TraitItem(..) = source {} else {
3207 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3208 self.record_def(id, resolution);
3213 fn type_ascription_suggestion(&self,
3214 err: &mut DiagnosticBuilder,
3216 debug!("type_ascription_suggetion {:?}", base_span);
3217 let cm = self.session.codemap();
3218 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3219 if let Some(sp) = self.current_type_ascription.last() {
3221 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3222 sp = cm.next_point(sp);
3223 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3224 debug!("snippet {:?}", snippet);
3225 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3226 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3227 debug!("{:?} {:?}", line_sp, line_base_sp);
3229 err.span_label(base_span,
3230 "expecting a type here because of type ascription");
3231 if line_sp != line_base_sp {
3232 err.span_suggestion_short(sp,
3233 "did you mean to use `;` here instead?",
3237 } else if snippet.trim().len() != 0 {
3238 debug!("tried to find type ascription `:` token, couldn't find it");
3248 fn self_type_is_available(&mut self, span: Span) -> bool {
3249 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3250 TypeNS, None, span);
3251 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3254 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3255 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3256 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3257 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3260 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3261 fn resolve_qpath_anywhere(&mut self,
3263 qself: Option<&QSelf>,
3265 primary_ns: Namespace,
3267 defer_to_typeck: bool,
3268 global_by_default: bool,
3269 crate_lint: CrateLint)
3270 -> Option<PathResolution> {
3271 let mut fin_res = None;
3272 // FIXME: can't resolve paths in macro namespace yet, macros are
3273 // processed by the little special hack below.
3274 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3275 if i == 0 || ns != primary_ns {
3276 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3277 // If defer_to_typeck, then resolution > no resolution,
3278 // otherwise full resolution > partial resolution > no resolution.
3279 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3281 res => if fin_res.is_none() { fin_res = res },
3285 let is_global = self.macro_prelude.get(&path[0].name).cloned()
3286 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3287 if primary_ns != MacroNS && (is_global ||
3288 self.macro_names.contains(&path[0].modern())) {
3289 // Return some dummy definition, it's enough for error reporting.
3291 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3297 /// Handles paths that may refer to associated items.
3298 fn resolve_qpath(&mut self,
3300 qself: Option<&QSelf>,
3304 global_by_default: bool,
3305 crate_lint: CrateLint)
3306 -> Option<PathResolution> {
3308 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3309 ns={:?}, span={:?}, global_by_default={:?})",
3318 if let Some(qself) = qself {
3319 if qself.position == 0 {
3320 // This is a case like `<T>::B`, where there is no
3321 // trait to resolve. In that case, we leave the `B`
3322 // segment to be resolved by type-check.
3323 return Some(PathResolution::with_unresolved_segments(
3324 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3328 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3330 // Currently, `path` names the full item (`A::B::C`, in
3331 // our example). so we extract the prefix of that that is
3332 // the trait (the slice upto and including
3333 // `qself.position`). And then we recursively resolve that,
3334 // but with `qself` set to `None`.
3336 // However, setting `qself` to none (but not changing the
3337 // span) loses the information about where this path
3338 // *actually* appears, so for the purposes of the crate
3339 // lint we pass along information that this is the trait
3340 // name from a fully qualified path, and this also
3341 // contains the full span (the `CrateLint::QPathTrait`).
3342 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3343 let res = self.smart_resolve_path_fragment(
3346 &path[..qself.position + 1],
3348 PathSource::TraitItem(ns),
3349 CrateLint::QPathTrait {
3351 qpath_span: qself.path_span,
3355 // The remaining segments (the `C` in our example) will
3356 // have to be resolved by type-check, since that requires doing
3357 // trait resolution.
3358 return Some(PathResolution::with_unresolved_segments(
3359 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3363 let result = match self.resolve_path(
3371 PathResult::NonModule(path_res) => path_res,
3372 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3373 PathResolution::new(module.def().unwrap())
3375 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3376 // don't report an error right away, but try to fallback to a primitive type.
3377 // So, we are still able to successfully resolve something like
3379 // use std::u8; // bring module u8 in scope
3380 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3381 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3382 // // not to non-existent std::u8::max_value
3385 // Such behavior is required for backward compatibility.
3386 // The same fallback is used when `a` resolves to nothing.
3387 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3388 PathResult::Failed(..)
3389 if (ns == TypeNS || path.len() > 1) &&
3390 self.primitive_type_table.primitive_types
3391 .contains_key(&path[0].name) => {
3392 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3393 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3395 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3396 PathResolution::new(module.def().unwrap()),
3397 PathResult::Failed(span, msg, false) => {
3398 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3399 err_path_resolution()
3401 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3402 PathResult::Failed(..) => return None,
3403 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3406 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3407 path[0].name != keywords::CrateRoot.name() &&
3408 path[0].name != keywords::DollarCrate.name() {
3409 let unqualified_result = {
3410 match self.resolve_path(
3412 &[*path.last().unwrap()],
3418 PathResult::NonModule(path_res) => path_res.base_def(),
3419 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3420 module.def().unwrap(),
3421 _ => return Some(result),
3424 if result.base_def() == unqualified_result {
3425 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3426 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3435 base_module: Option<ModuleOrUniformRoot<'a>>,
3437 opt_ns: Option<Namespace>, // `None` indicates a module path
3440 crate_lint: CrateLint,
3441 ) -> PathResult<'a> {
3442 let mut module = base_module;
3443 let mut allow_super = true;
3444 let mut second_binding = None;
3447 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3448 path_span={:?}, crate_lint={:?})",
3456 for (i, &ident) in path.iter().enumerate() {
3457 debug!("resolve_path ident {} {:?}", i, ident);
3458 let is_last = i == path.len() - 1;
3459 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3460 let name = ident.name;
3462 if i == 0 && ns == TypeNS && name == keywords::SelfValue.name() {
3463 let mut ctxt = ident.span.ctxt().modern();
3464 module = Some(ModuleOrUniformRoot::Module(
3465 self.resolve_self(&mut ctxt, self.current_module)));
3467 } else if allow_super && ns == TypeNS && name == keywords::Super.name() {
3468 let mut ctxt = ident.span.ctxt().modern();
3469 let self_module_parent = match i {
3470 0 => self.resolve_self(&mut ctxt, self.current_module).parent,
3472 Some(ModuleOrUniformRoot::Module(module)) => module.parent,
3476 if let Some(parent) = self_module_parent {
3477 module = Some(ModuleOrUniformRoot::Module(
3478 self.resolve_self(&mut ctxt, parent)));
3481 let msg = "There are too many initial `super`s.".to_string();
3482 return PathResult::Failed(ident.span, msg, false);
3485 allow_super = false;
3489 if name == keywords::Extern.name() ||
3490 name == keywords::CrateRoot.name() &&
3491 self.session.features_untracked().extern_absolute_paths &&
3492 self.session.rust_2018() {
3493 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3497 if (i == 0 && name == keywords::CrateRoot.name()) ||
3498 (i == 0 && name == keywords::Crate.name()) ||
3499 (i == 0 && name == keywords::DollarCrate.name()) ||
3500 (i == 1 && name == keywords::Crate.name() &&
3501 path[0].name == keywords::CrateRoot.name()) {
3502 // `::a::b`, `crate::a::b`, `::crate::a::b` or `$crate::a::b`
3503 module = Some(ModuleOrUniformRoot::Module(
3504 self.resolve_crate_root(ident)));
3509 // Report special messages for path segment keywords in wrong positions.
3510 if name == keywords::CrateRoot.name() && i != 0 ||
3511 name == keywords::DollarCrate.name() && i != 0 ||
3512 name == keywords::SelfValue.name() && i != 0 ||
3513 name == keywords::SelfType.name() && i != 0 ||
3514 name == keywords::Super.name() && i != 0 ||
3515 name == keywords::Extern.name() && i != 0 ||
3516 // we allow crate::foo and ::crate::foo but nothing else
3517 name == keywords::Crate.name() && i > 1 &&
3518 path[0].name != keywords::CrateRoot.name() ||
3519 name == keywords::Crate.name() && path.len() == 1 {
3520 let name_str = if name == keywords::CrateRoot.name() {
3521 "crate root".to_string()
3523 format!("`{}`", name)
3525 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3526 format!("global paths cannot start with {}", name_str)
3528 format!("{} in paths can only be used in start position", name_str)
3530 return PathResult::Failed(ident.span, msg, false);
3533 let binding = if let Some(module) = module {
3534 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3535 } else if opt_ns == Some(MacroNS) {
3536 assert!(ns == TypeNS);
3537 self.resolve_lexical_macro_path_segment(ident, ns, record_used, record_used,
3538 false, path_span).map(MacroBinding::binding)
3540 let record_used_id =
3541 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3542 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3543 // we found a locally-imported or available item/module
3544 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3545 // we found a local variable or type param
3546 Some(LexicalScopeBinding::Def(def))
3547 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3548 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3552 _ => Err(if record_used { Determined } else { Undetermined }),
3559 second_binding = Some(binding);
3561 let def = binding.def();
3562 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3563 if let Some(next_module) = binding.module() {
3564 module = Some(ModuleOrUniformRoot::Module(next_module));
3565 } else if def == Def::ToolMod && i + 1 != path.len() {
3566 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3567 return PathResult::NonModule(PathResolution::new(def));
3568 } else if def == Def::Err {
3569 return PathResult::NonModule(err_path_resolution());
3570 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3571 self.lint_if_path_starts_with_module(
3577 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3578 def, path.len() - i - 1
3581 return PathResult::Failed(ident.span,
3582 format!("Not a module `{}`", ident),
3586 Err(Undetermined) => return PathResult::Indeterminate,
3587 Err(Determined) => {
3588 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3589 if opt_ns.is_some() && !module.is_normal() {
3590 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3591 module.def().unwrap(), path.len() - i
3595 let module_def = match module {
3596 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3599 let msg = if module_def == self.graph_root.def() {
3600 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3601 let mut candidates =
3602 self.lookup_import_candidates(name, TypeNS, is_mod);
3603 candidates.sort_by_cached_key(|c| {
3604 (c.path.segments.len(), c.path.to_string())
3606 if let Some(candidate) = candidates.get(0) {
3607 format!("Did you mean `{}`?", candidate.path)
3609 format!("Maybe a missing `extern crate {};`?", ident)
3612 format!("Use of undeclared type or module `{}`", ident)
3614 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3616 return PathResult::Failed(ident.span, msg, is_last);
3621 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3623 PathResult::Module(module.unwrap_or_else(|| {
3624 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3629 fn lint_if_path_starts_with_module(
3631 crate_lint: CrateLint,
3634 second_binding: Option<&NameBinding>,
3636 // In the 2018 edition this lint is a hard error, so nothing to do
3637 if self.session.rust_2018() {
3641 // In the 2015 edition there's no use in emitting lints unless the
3642 // crate's already enabled the feature that we're going to suggest
3643 if !self.session.features_untracked().crate_in_paths {
3647 let (diag_id, diag_span) = match crate_lint {
3648 CrateLint::No => return,
3649 CrateLint::SimplePath(id) => (id, path_span),
3650 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3651 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3654 let first_name = match path.get(0) {
3655 Some(ident) => ident.name,
3659 // We're only interested in `use` paths which should start with
3660 // `{{root}}` or `extern` currently.
3661 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3666 // If this import looks like `crate::...` it's already good
3667 Some(ident) if ident.name == keywords::Crate.name() => return,
3668 // Otherwise go below to see if it's an extern crate
3670 // If the path has length one (and it's `CrateRoot` most likely)
3671 // then we don't know whether we're gonna be importing a crate or an
3672 // item in our crate. Defer this lint to elsewhere
3676 // If the first element of our path was actually resolved to an
3677 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3678 // warning, this looks all good!
3679 if let Some(binding) = second_binding {
3680 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3681 // Careful: we still want to rewrite paths from
3682 // renamed extern crates.
3683 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3689 let diag = lint::builtin::BuiltinLintDiagnostics
3690 ::AbsPathWithModule(diag_span);
3691 self.session.buffer_lint_with_diagnostic(
3692 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3694 "absolute paths must start with `self`, `super`, \
3695 `crate`, or an external crate name in the 2018 edition",
3699 // Resolve a local definition, potentially adjusting for closures.
3700 fn adjust_local_def(&mut self,
3705 span: Span) -> Def {
3706 let ribs = &self.ribs[ns][rib_index + 1..];
3708 // An invalid forward use of a type parameter from a previous default.
3709 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3711 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3713 assert_eq!(def, Def::Err);
3719 span_bug!(span, "unexpected {:?} in bindings", def)
3721 Def::Local(node_id) => {
3724 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3725 ForwardTyParamBanRibKind => {
3726 // Nothing to do. Continue.
3728 ClosureRibKind(function_id) => {
3731 let seen = self.freevars_seen
3733 .or_insert_with(|| NodeMap());
3734 if let Some(&index) = seen.get(&node_id) {
3735 def = Def::Upvar(node_id, index, function_id);
3738 let vec = self.freevars
3740 .or_insert_with(|| vec![]);
3741 let depth = vec.len();
3742 def = Def::Upvar(node_id, depth, function_id);
3749 seen.insert(node_id, depth);
3752 ItemRibKind | TraitOrImplItemRibKind => {
3753 // This was an attempt to access an upvar inside a
3754 // named function item. This is not allowed, so we
3757 resolve_error(self, span,
3758 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3762 ConstantItemRibKind => {
3763 // Still doesn't deal with upvars
3765 resolve_error(self, span,
3766 ResolutionError::AttemptToUseNonConstantValueInConstant);
3773 Def::TyParam(..) | Def::SelfTy(..) => {
3776 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3777 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3778 ConstantItemRibKind => {
3779 // Nothing to do. Continue.
3782 // This was an attempt to use a type parameter outside
3785 resolve_error(self, span,
3786 ResolutionError::TypeParametersFromOuterFunction(def));
3798 fn lookup_assoc_candidate<FilterFn>(&mut self,
3801 filter_fn: FilterFn)
3802 -> Option<AssocSuggestion>
3803 where FilterFn: Fn(Def) -> bool
3805 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3807 TyKind::Path(None, _) => Some(t.id),
3808 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3809 // This doesn't handle the remaining `Ty` variants as they are not
3810 // that commonly the self_type, it might be interesting to provide
3811 // support for those in future.
3816 // Fields are generally expected in the same contexts as locals.
3817 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3818 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3819 // Look for a field with the same name in the current self_type.
3820 if let Some(resolution) = self.def_map.get(&node_id) {
3821 match resolution.base_def() {
3822 Def::Struct(did) | Def::Union(did)
3823 if resolution.unresolved_segments() == 0 => {
3824 if let Some(field_names) = self.field_names.get(&did) {
3825 if field_names.iter().any(|&field_name| ident.name == field_name) {
3826 return Some(AssocSuggestion::Field);
3836 // Look for associated items in the current trait.
3837 if let Some((module, _)) = self.current_trait_ref {
3838 if let Ok(binding) = self.resolve_ident_in_module(
3839 ModuleOrUniformRoot::Module(module),
3845 let def = binding.def();
3847 return Some(if self.has_self.contains(&def.def_id()) {
3848 AssocSuggestion::MethodWithSelf
3850 AssocSuggestion::AssocItem
3859 fn lookup_typo_candidate<FilterFn>(&mut self,
3862 filter_fn: FilterFn,
3865 where FilterFn: Fn(Def) -> bool
3867 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3868 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3869 if let Some(binding) = resolution.borrow().binding {
3870 if filter_fn(binding.def()) {
3871 names.push(ident.name);
3877 let mut names = Vec::new();
3878 if path.len() == 1 {
3879 // Search in lexical scope.
3880 // Walk backwards up the ribs in scope and collect candidates.
3881 for rib in self.ribs[ns].iter().rev() {
3882 // Locals and type parameters
3883 for (ident, def) in &rib.bindings {
3884 if filter_fn(*def) {
3885 names.push(ident.name);
3889 if let ModuleRibKind(module) = rib.kind {
3890 // Items from this module
3891 add_module_candidates(module, &mut names);
3893 if let ModuleKind::Block(..) = module.kind {
3894 // We can see through blocks
3896 // Items from the prelude
3897 if !module.no_implicit_prelude {
3898 names.extend(self.extern_prelude.iter().cloned());
3899 if let Some(prelude) = self.prelude {
3900 add_module_candidates(prelude, &mut names);
3907 // Add primitive types to the mix
3908 if filter_fn(Def::PrimTy(TyBool)) {
3910 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3914 // Search in module.
3915 let mod_path = &path[..path.len() - 1];
3916 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
3917 false, span, CrateLint::No) {
3918 if let ModuleOrUniformRoot::Module(module) = module {
3919 add_module_candidates(module, &mut names);
3924 let name = path[path.len() - 1].name;
3925 // Make sure error reporting is deterministic.
3926 names.sort_by_cached_key(|name| name.as_str());
3927 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3928 Some(found) if found != name => Some(found),
3933 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3934 where F: FnOnce(&mut Resolver)
3936 if let Some(label) = label {
3937 self.unused_labels.insert(id, label.ident.span);
3938 let def = Def::Label(id);
3939 self.with_label_rib(|this| {
3940 let ident = label.ident.modern_and_legacy();
3941 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
3949 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3950 self.with_resolved_label(label, id, |this| this.visit_block(block));
3953 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3954 // First, record candidate traits for this expression if it could
3955 // result in the invocation of a method call.
3957 self.record_candidate_traits_for_expr_if_necessary(expr);
3959 // Next, resolve the node.
3961 ExprKind::Path(ref qself, ref path) => {
3962 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3963 visit::walk_expr(self, expr);
3966 ExprKind::Struct(ref path, ..) => {
3967 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3968 visit::walk_expr(self, expr);
3971 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3972 let def = self.search_label(label.ident, |rib, ident| {
3973 rib.bindings.get(&ident.modern_and_legacy()).cloned()
3977 // Search again for close matches...
3978 // Picks the first label that is "close enough", which is not necessarily
3979 // the closest match
3980 let close_match = self.search_label(label.ident, |rib, ident| {
3981 let names = rib.bindings.iter().map(|(id, _)| &id.name);
3982 find_best_match_for_name(names, &*ident.as_str(), None)
3984 self.record_def(expr.id, err_path_resolution());
3987 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
3990 Some(Def::Label(id)) => {
3991 // Since this def is a label, it is never read.
3992 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
3993 self.unused_labels.remove(&id);
3996 span_bug!(expr.span, "label wasn't mapped to a label def!");
4000 // visit `break` argument if any
4001 visit::walk_expr(self, expr);
4004 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4005 self.visit_expr(subexpression);
4007 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4008 let mut bindings_list = FxHashMap();
4010 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4012 // This has to happen *after* we determine which pat_idents are variants
4013 self.check_consistent_bindings(pats);
4014 self.visit_block(if_block);
4015 self.ribs[ValueNS].pop();
4017 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4020 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4022 ExprKind::While(ref subexpression, ref block, label) => {
4023 self.with_resolved_label(label, expr.id, |this| {
4024 this.visit_expr(subexpression);
4025 this.visit_block(block);
4029 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4030 self.with_resolved_label(label, expr.id, |this| {
4031 this.visit_expr(subexpression);
4032 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4033 let mut bindings_list = FxHashMap();
4035 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4037 // This has to happen *after* we determine which pat_idents are variants
4038 this.check_consistent_bindings(pats);
4039 this.visit_block(block);
4040 this.ribs[ValueNS].pop();
4044 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4045 self.visit_expr(subexpression);
4046 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4047 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4049 self.resolve_labeled_block(label, expr.id, block);
4051 self.ribs[ValueNS].pop();
4054 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4056 // Equivalent to `visit::walk_expr` + passing some context to children.
4057 ExprKind::Field(ref subexpression, _) => {
4058 self.resolve_expr(subexpression, Some(expr));
4060 ExprKind::MethodCall(ref segment, ref arguments) => {
4061 let mut arguments = arguments.iter();
4062 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4063 for argument in arguments {
4064 self.resolve_expr(argument, None);
4066 self.visit_path_segment(expr.span, segment);
4069 ExprKind::Call(ref callee, ref arguments) => {
4070 self.resolve_expr(callee, Some(expr));
4071 for argument in arguments {
4072 self.resolve_expr(argument, None);
4075 ExprKind::Type(ref type_expr, _) => {
4076 self.current_type_ascription.push(type_expr.span);
4077 visit::walk_expr(self, expr);
4078 self.current_type_ascription.pop();
4080 // Resolve the body of async exprs inside the async closure to which they desugar
4081 ExprKind::Async(_, async_closure_id, ref block) => {
4082 let rib_kind = ClosureRibKind(async_closure_id);
4083 self.ribs[ValueNS].push(Rib::new(rib_kind));
4084 self.label_ribs.push(Rib::new(rib_kind));
4085 self.visit_block(&block);
4086 self.label_ribs.pop();
4087 self.ribs[ValueNS].pop();
4089 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4090 // resolve the arguments within the proper scopes so that usages of them inside the
4091 // closure are detected as upvars rather than normal closure arg usages.
4093 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4094 ref fn_decl, ref body, _span,
4096 let rib_kind = ClosureRibKind(expr.id);
4097 self.ribs[ValueNS].push(Rib::new(rib_kind));
4098 self.label_ribs.push(Rib::new(rib_kind));
4099 // Resolve arguments:
4100 let mut bindings_list = FxHashMap();
4101 for argument in &fn_decl.inputs {
4102 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4103 self.visit_ty(&argument.ty);
4105 // No need to resolve return type-- the outer closure return type is
4106 // FunctionRetTy::Default
4108 // Now resolve the inner closure
4110 let rib_kind = ClosureRibKind(inner_closure_id);
4111 self.ribs[ValueNS].push(Rib::new(rib_kind));
4112 self.label_ribs.push(Rib::new(rib_kind));
4113 // No need to resolve arguments: the inner closure has none.
4114 // Resolve the return type:
4115 visit::walk_fn_ret_ty(self, &fn_decl.output);
4117 self.visit_expr(body);
4118 self.label_ribs.pop();
4119 self.ribs[ValueNS].pop();
4121 self.label_ribs.pop();
4122 self.ribs[ValueNS].pop();
4125 visit::walk_expr(self, expr);
4130 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4132 ExprKind::Field(_, ident) => {
4133 // FIXME(#6890): Even though you can't treat a method like a
4134 // field, we need to add any trait methods we find that match
4135 // the field name so that we can do some nice error reporting
4136 // later on in typeck.
4137 let traits = self.get_traits_containing_item(ident, ValueNS);
4138 self.trait_map.insert(expr.id, traits);
4140 ExprKind::MethodCall(ref segment, ..) => {
4141 debug!("(recording candidate traits for expr) recording traits for {}",
4143 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4144 self.trait_map.insert(expr.id, traits);
4152 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4153 -> Vec<TraitCandidate> {
4154 debug!("(getting traits containing item) looking for '{}'", ident.name);
4156 let mut found_traits = Vec::new();
4157 // Look for the current trait.
4158 if let Some((module, _)) = self.current_trait_ref {
4159 if self.resolve_ident_in_module(
4160 ModuleOrUniformRoot::Module(module),
4166 let def_id = module.def_id().unwrap();
4167 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4171 ident.span = ident.span.modern();
4172 let mut search_module = self.current_module;
4174 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4175 search_module = unwrap_or!(
4176 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4180 if let Some(prelude) = self.prelude {
4181 if !search_module.no_implicit_prelude {
4182 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4189 fn get_traits_in_module_containing_item(&mut self,
4193 found_traits: &mut Vec<TraitCandidate>) {
4194 assert!(ns == TypeNS || ns == ValueNS);
4195 let mut traits = module.traits.borrow_mut();
4196 if traits.is_none() {
4197 let mut collected_traits = Vec::new();
4198 module.for_each_child(|name, ns, binding| {
4199 if ns != TypeNS { return }
4200 if let Def::Trait(_) = binding.def() {
4201 collected_traits.push((name, binding));
4204 *traits = Some(collected_traits.into_boxed_slice());
4207 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4208 let module = binding.module().unwrap();
4209 let mut ident = ident;
4210 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4213 if self.resolve_ident_in_module_unadjusted(
4214 ModuleOrUniformRoot::Module(module),
4221 let import_id = match binding.kind {
4222 NameBindingKind::Import { directive, .. } => {
4223 self.maybe_unused_trait_imports.insert(directive.id);
4224 self.add_to_glob_map(directive.id, trait_name);
4229 let trait_def_id = module.def_id().unwrap();
4230 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4235 /// When name resolution fails, this method can be used to look up candidate
4236 /// entities with the expected name. It allows filtering them using the
4237 /// supplied predicate (which should be used to only accept the types of
4238 /// definitions expected e.g. traits). The lookup spans across all crates.
4240 /// NOTE: The method does not look into imports, but this is not a problem,
4241 /// since we report the definitions (thus, the de-aliased imports).
4242 fn lookup_import_candidates<FilterFn>(&mut self,
4244 namespace: Namespace,
4245 filter_fn: FilterFn)
4246 -> Vec<ImportSuggestion>
4247 where FilterFn: Fn(Def) -> bool
4249 let mut candidates = Vec::new();
4250 let mut worklist = Vec::new();
4251 let mut seen_modules = FxHashSet();
4252 worklist.push((self.graph_root, Vec::new(), false));
4254 while let Some((in_module,
4256 in_module_is_extern)) = worklist.pop() {
4257 self.populate_module_if_necessary(in_module);
4259 // We have to visit module children in deterministic order to avoid
4260 // instabilities in reported imports (#43552).
4261 in_module.for_each_child_stable(|ident, ns, name_binding| {
4262 // avoid imports entirely
4263 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4264 // avoid non-importable candidates as well
4265 if !name_binding.is_importable() { return; }
4267 // collect results based on the filter function
4268 if ident.name == lookup_name && ns == namespace {
4269 if filter_fn(name_binding.def()) {
4271 let mut segms = if self.session.rust_2018() && !in_module_is_extern {
4272 // crate-local absolute paths start with `crate::` in edition 2018
4273 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4274 let mut full_segms = vec![
4275 ast::PathSegment::from_ident(keywords::Crate.ident())
4277 full_segms.extend(path_segments.clone());
4280 path_segments.clone()
4283 segms.push(ast::PathSegment::from_ident(ident));
4285 span: name_binding.span,
4288 // the entity is accessible in the following cases:
4289 // 1. if it's defined in the same crate, it's always
4290 // accessible (since private entities can be made public)
4291 // 2. if it's defined in another crate, it's accessible
4292 // only if both the module is public and the entity is
4293 // declared as public (due to pruning, we don't explore
4294 // outside crate private modules => no need to check this)
4295 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4296 candidates.push(ImportSuggestion { path: path });
4301 // collect submodules to explore
4302 if let Some(module) = name_binding.module() {
4304 let mut path_segments = path_segments.clone();
4305 path_segments.push(ast::PathSegment::from_ident(ident));
4307 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4308 // add the module to the lookup
4309 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4310 if seen_modules.insert(module.def_id().unwrap()) {
4311 worklist.push((module, path_segments, is_extern));
4321 fn find_module(&mut self,
4323 -> Option<(Module<'a>, ImportSuggestion)>
4325 let mut result = None;
4326 let mut worklist = Vec::new();
4327 let mut seen_modules = FxHashSet();
4328 worklist.push((self.graph_root, Vec::new()));
4330 while let Some((in_module, path_segments)) = worklist.pop() {
4331 // abort if the module is already found
4332 if result.is_some() { break; }
4334 self.populate_module_if_necessary(in_module);
4336 in_module.for_each_child_stable(|ident, _, name_binding| {
4337 // abort if the module is already found or if name_binding is private external
4338 if result.is_some() || !name_binding.vis.is_visible_locally() {
4341 if let Some(module) = name_binding.module() {
4343 let mut path_segments = path_segments.clone();
4344 path_segments.push(ast::PathSegment::from_ident(ident));
4345 if module.def() == Some(module_def) {
4347 span: name_binding.span,
4348 segments: path_segments,
4350 result = Some((module, ImportSuggestion { path: path }));
4352 // add the module to the lookup
4353 if seen_modules.insert(module.def_id().unwrap()) {
4354 worklist.push((module, path_segments));
4364 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4365 if let Def::Enum(..) = enum_def {} else {
4366 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4369 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4370 self.populate_module_if_necessary(enum_module);
4372 let mut variants = Vec::new();
4373 enum_module.for_each_child_stable(|ident, _, name_binding| {
4374 if let Def::Variant(..) = name_binding.def() {
4375 let mut segms = enum_import_suggestion.path.segments.clone();
4376 segms.push(ast::PathSegment::from_ident(ident));
4377 variants.push(Path {
4378 span: name_binding.span,
4387 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4388 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4389 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4390 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4394 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4396 ast::VisibilityKind::Public => ty::Visibility::Public,
4397 ast::VisibilityKind::Crate(..) => {
4398 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4400 ast::VisibilityKind::Inherited => {
4401 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4403 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4404 // Visibilities are resolved as global by default, add starting root segment.
4405 let segments = path.make_root().iter().chain(path.segments.iter())
4406 .map(|seg| seg.ident)
4407 .collect::<Vec<_>>();
4408 let def = self.smart_resolve_path_fragment(
4413 PathSource::Visibility,
4414 CrateLint::SimplePath(id),
4416 if def == Def::Err {
4417 ty::Visibility::Public
4419 let vis = ty::Visibility::Restricted(def.def_id());
4420 if self.is_accessible(vis) {
4423 self.session.span_err(path.span, "visibilities can only be restricted \
4424 to ancestor modules");
4425 ty::Visibility::Public
4432 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4433 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4436 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4437 vis.is_accessible_from(module.normal_ancestor_id, self)
4440 fn report_errors(&mut self, krate: &Crate) {
4441 self.report_shadowing_errors();
4442 self.report_with_use_injections(krate);
4443 self.report_proc_macro_import(krate);
4444 let mut reported_spans = FxHashSet();
4446 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4447 let msg = "macro-expanded `macro_export` macros from the current crate \
4448 cannot be referred to by absolute paths";
4449 self.session.struct_span_err(span_use, msg)
4450 .span_note(span_def, "the macro is defined here")
4454 for &AmbiguityError { span, name, b1, b2, lexical } in &self.ambiguity_errors {
4455 if !reported_spans.insert(span) { continue }
4456 let participle = |binding: &NameBinding| {
4457 if binding.is_import() { "imported" } else { "defined" }
4459 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
4460 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
4461 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
4462 format!("consider adding an explicit import of `{}` to disambiguate", name)
4463 } else if let Def::Macro(..) = b1.def() {
4464 format!("macro-expanded {} do not shadow",
4465 if b1.is_import() { "macro imports" } else { "macros" })
4467 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4468 if b1.is_import() { "imports" } else { "items" })
4471 let mut err = struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
4472 err.span_note(b1.span, &msg1);
4474 Def::Macro(..) if b2.span.is_dummy() =>
4475 err.note(&format!("`{}` is also a builtin macro", name)),
4476 _ => err.span_note(b2.span, &msg2),
4478 err.note(¬e).emit();
4481 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4482 if !reported_spans.insert(span) { continue }
4483 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4487 fn report_with_use_injections(&mut self, krate: &Crate) {
4488 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4489 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4490 if !candidates.is_empty() {
4491 show_candidates(&mut err, span, &candidates, better, found_use);
4497 fn report_shadowing_errors(&mut self) {
4498 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
4499 self.resolve_legacy_scope(scope, ident, true);
4502 let mut reported_errors = FxHashSet();
4503 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4504 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4505 reported_errors.insert((binding.ident, binding.span)) {
4506 let msg = format!("`{}` is already in scope", binding.ident);
4507 self.session.struct_span_err(binding.span, &msg)
4508 .note("macro-expanded `macro_rules!`s may not shadow \
4509 existing macros (see RFC 1560)")
4515 fn report_conflict<'b>(&mut self,
4519 new_binding: &NameBinding<'b>,
4520 old_binding: &NameBinding<'b>) {
4521 // Error on the second of two conflicting names
4522 if old_binding.span.lo() > new_binding.span.lo() {
4523 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4526 let container = match parent.kind {
4527 ModuleKind::Def(Def::Mod(_), _) => "module",
4528 ModuleKind::Def(Def::Trait(_), _) => "trait",
4529 ModuleKind::Block(..) => "block",
4533 let old_noun = match old_binding.is_import() {
4535 false => "definition",
4538 let new_participle = match new_binding.is_import() {
4543 let (name, span) = (ident.name, self.session.codemap().def_span(new_binding.span));
4545 if let Some(s) = self.name_already_seen.get(&name) {
4551 let old_kind = match (ns, old_binding.module()) {
4552 (ValueNS, _) => "value",
4553 (MacroNS, _) => "macro",
4554 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4555 (TypeNS, Some(module)) if module.is_normal() => "module",
4556 (TypeNS, Some(module)) if module.is_trait() => "trait",
4557 (TypeNS, _) => "type",
4560 let msg = format!("the name `{}` is defined multiple times", name);
4562 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4563 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4564 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4565 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4566 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4568 _ => match (old_binding.is_import(), new_binding.is_import()) {
4569 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4570 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4571 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4575 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4580 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4581 if !old_binding.span.is_dummy() {
4582 err.span_label(self.session.codemap().def_span(old_binding.span),
4583 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4586 // See https://github.com/rust-lang/rust/issues/32354
4587 if old_binding.is_import() || new_binding.is_import() {
4588 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4594 let cm = self.session.codemap();
4595 let rename_msg = "You can use `as` to change the binding name of the import";
4597 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4598 binding.is_renamed_extern_crate()) {
4599 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4600 format!("Other{}", name)
4602 format!("other_{}", name)
4605 err.span_suggestion(binding.span,
4607 if snippet.ends_with(';') {
4608 format!("{} as {};",
4609 &snippet[..snippet.len()-1],
4612 format!("{} as {}", snippet, suggested_name)
4615 err.span_label(binding.span, rename_msg);
4620 self.name_already_seen.insert(name, span);
4623 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
4624 if self.use_extern_macros { return; }
4627 if attr.path.segments.len() > 1 {
4630 let ident = attr.path.segments[0].ident;
4631 let result = self.resolve_lexical_macro_path_segment(ident,
4637 if let Ok(binding) = result {
4638 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
4639 attr::mark_known(attr);
4641 let msg = "attribute procedural macros are experimental";
4642 let feature = "use_extern_macros";
4644 feature_err(&self.session.parse_sess, feature,
4645 attr.span, GateIssue::Language, msg)
4646 .span_label(binding.span(), "procedural macro imported here")
4654 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4655 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4658 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4659 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4662 fn names_to_string(idents: &[Ident]) -> String {
4663 let mut result = String::new();
4664 for (i, ident) in idents.iter()
4665 .filter(|ident| ident.name != keywords::CrateRoot.name())
4668 result.push_str("::");
4670 result.push_str(&ident.as_str());
4675 fn path_names_to_string(path: &Path) -> String {
4676 names_to_string(&path.segments.iter()
4677 .map(|seg| seg.ident)
4678 .collect::<Vec<_>>())
4681 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4682 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4683 let variant_path = &suggestion.path;
4684 let variant_path_string = path_names_to_string(variant_path);
4686 let path_len = suggestion.path.segments.len();
4687 let enum_path = ast::Path {
4688 span: suggestion.path.span,
4689 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4691 let enum_path_string = path_names_to_string(&enum_path);
4693 (suggestion.path.span, variant_path_string, enum_path_string)
4697 /// When an entity with a given name is not available in scope, we search for
4698 /// entities with that name in all crates. This method allows outputting the
4699 /// results of this search in a programmer-friendly way
4700 fn show_candidates(err: &mut DiagnosticBuilder,
4701 // This is `None` if all placement locations are inside expansions
4703 candidates: &[ImportSuggestion],
4707 // we want consistent results across executions, but candidates are produced
4708 // by iterating through a hash map, so make sure they are ordered:
4709 let mut path_strings: Vec<_> =
4710 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4711 path_strings.sort();
4713 let better = if better { "better " } else { "" };
4714 let msg_diff = match path_strings.len() {
4715 1 => " is found in another module, you can import it",
4716 _ => "s are found in other modules, you can import them",
4718 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4720 if let Some(span) = span {
4721 for candidate in &mut path_strings {
4722 // produce an additional newline to separate the new use statement
4723 // from the directly following item.
4724 let additional_newline = if found_use {
4729 *candidate = format!("use {};\n{}", candidate, additional_newline);
4732 err.span_suggestions(span, &msg, path_strings);
4736 for candidate in path_strings {
4738 msg.push_str(&candidate);
4743 /// A somewhat inefficient routine to obtain the name of a module.
4744 fn module_to_string(module: Module) -> Option<String> {
4745 let mut names = Vec::new();
4747 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4748 if let ModuleKind::Def(_, name) = module.kind {
4749 if let Some(parent) = module.parent {
4750 names.push(Ident::with_empty_ctxt(name));
4751 collect_mod(names, parent);
4754 // danger, shouldn't be ident?
4755 names.push(Ident::from_str("<opaque>"));
4756 collect_mod(names, module.parent.unwrap());
4759 collect_mod(&mut names, module);
4761 if names.is_empty() {
4764 Some(names_to_string(&names.into_iter()
4766 .collect::<Vec<_>>()))
4769 fn err_path_resolution() -> PathResolution {
4770 PathResolution::new(Def::Err)
4773 #[derive(PartialEq,Copy, Clone)]
4774 pub enum MakeGlobMap {
4779 #[derive(Copy, Clone, Debug)]
4781 /// Do not issue the lint
4784 /// This lint applies to some random path like `impl ::foo::Bar`
4785 /// or whatever. In this case, we can take the span of that path.
4788 /// This lint comes from a `use` statement. In this case, what we
4789 /// care about really is the *root* `use` statement; e.g., if we
4790 /// have nested things like `use a::{b, c}`, we care about the
4792 UsePath { root_id: NodeId, root_span: Span },
4794 /// This is the "trait item" from a fully qualified path. For example,
4795 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4796 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4797 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4801 fn node_id(&self) -> Option<NodeId> {
4803 CrateLint::No => None,
4804 CrateLint::SimplePath(id) |
4805 CrateLint::UsePath { root_id: id, .. } |
4806 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4811 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }