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 #![deny(bare_trait_objects)]
13 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
14 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
15 html_root_url = "https://doc.rust-lang.org/nightly/")]
17 #![feature(crate_visibility_modifier)]
18 #![feature(rustc_diagnostic_macros)]
19 #![feature(slice_sort_by_cached_key)]
25 extern crate syntax_pos;
26 extern crate rustc_errors as errors;
30 extern crate rustc_data_structures;
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, CrateLoader};
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 syntax::codemap::CodeMap;
50 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
51 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
52 use syntax::ext::base::SyntaxExtension;
53 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
54 use syntax::ext::base::MacroKind;
55 use syntax::symbol::{Symbol, keywords};
56 use syntax::util::lev_distance::find_best_match_for_name;
58 use syntax::visit::{self, FnKind, Visitor};
60 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
61 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
62 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
63 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
64 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
65 use syntax::feature_gate::{feature_err, GateIssue};
68 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
69 use errors::{DiagnosticBuilder, DiagnosticId};
71 use std::cell::{Cell, RefCell};
73 use std::collections::BTreeSet;
76 use std::mem::replace;
77 use rustc_data_structures::sync::Lrc;
79 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
80 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
82 // NB: This module needs to be declared first so diagnostics are
83 // registered before they are used.
88 mod build_reduced_graph;
91 /// A free importable items suggested in case of resolution failure.
92 struct ImportSuggestion {
96 /// A field or associated item from self type suggested in case of resolution failure.
97 enum AssocSuggestion {
104 struct BindingError {
106 origin: BTreeSet<Span>,
107 target: BTreeSet<Span>,
110 impl PartialOrd for BindingError {
111 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
112 Some(self.cmp(other))
116 impl PartialEq for BindingError {
117 fn eq(&self, other: &BindingError) -> bool {
118 self.name == other.name
122 impl Ord for BindingError {
123 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
124 self.name.cmp(&other.name)
128 enum ResolutionError<'a> {
129 /// error E0401: can't use type parameters from outer function
130 TypeParametersFromOuterFunction(Def),
131 /// error E0403: the name is already used for a type parameter in this type parameter list
132 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
133 /// error E0407: method is not a member of trait
134 MethodNotMemberOfTrait(Name, &'a str),
135 /// error E0437: type is not a member of trait
136 TypeNotMemberOfTrait(Name, &'a str),
137 /// error E0438: const is not a member of trait
138 ConstNotMemberOfTrait(Name, &'a str),
139 /// error E0408: variable `{}` is not bound in all patterns
140 VariableNotBoundInPattern(&'a BindingError),
141 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
142 VariableBoundWithDifferentMode(Name, Span),
143 /// error E0415: identifier is bound more than once in this parameter list
144 IdentifierBoundMoreThanOnceInParameterList(&'a str),
145 /// error E0416: identifier is bound more than once in the same pattern
146 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
147 /// error E0426: use of undeclared label
148 UndeclaredLabel(&'a str, Option<Name>),
149 /// error E0429: `self` imports are only allowed within a { } list
150 SelfImportsOnlyAllowedWithin,
151 /// error E0430: `self` import can only appear once in the list
152 SelfImportCanOnlyAppearOnceInTheList,
153 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
154 SelfImportOnlyInImportListWithNonEmptyPrefix,
155 /// error E0432: unresolved import
156 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
157 /// error E0433: failed to resolve
158 FailedToResolve(&'a str),
159 /// error E0434: can't capture dynamic environment in a fn item
160 CannotCaptureDynamicEnvironmentInFnItem,
161 /// error E0435: attempt to use a non-constant value in a constant
162 AttemptToUseNonConstantValueInConstant,
163 /// error E0530: X bindings cannot shadow Ys
164 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
165 /// error E0128: type parameters with a default cannot use forward declared identifiers
166 ForwardDeclaredTyParam,
169 /// Combines an error with provided span and emits it
171 /// This takes the error provided, combines it with the span and any additional spans inside the
172 /// error and emits it.
173 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
175 resolution_error: ResolutionError<'a>) {
176 resolve_struct_error(resolver, span, resolution_error).emit();
179 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
181 resolution_error: ResolutionError<'a>)
182 -> DiagnosticBuilder<'sess> {
183 match resolution_error {
184 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
185 let mut err = struct_span_err!(resolver.session,
188 "can't use type parameters from outer function");
189 err.span_label(span, "use of type variable from outer function");
191 let cm = resolver.session.codemap();
193 Def::SelfTy(_, maybe_impl_defid) => {
194 if let Some(impl_span) = maybe_impl_defid.map_or(None,
195 |def_id| resolver.definitions.opt_span(def_id)) {
196 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
197 "`Self` type implicitely declared here, on the `impl`");
200 Def::TyParam(typaram_defid) => {
201 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
202 err.span_label(typaram_span, "type variable from outer function");
205 Def::Mod(..) | Def::Struct(..) | Def::Union(..) | Def::Enum(..) | Def::Variant(..) |
206 Def::Trait(..) | Def::TyAlias(..) | Def::TyForeign(..) | Def::TraitAlias(..) |
207 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::Fn(..) | Def::Const(..) |
208 Def::Static(..) | Def::StructCtor(..) | Def::VariantCtor(..) | Def::Method(..) |
209 Def::AssociatedConst(..) | Def::Local(..) | Def::Upvar(..) | Def::Label(..) |
210 Def::Existential(..) | Def::AssociatedExistential(..) |
211 Def::Macro(..) | Def::GlobalAsm(..) | Def::Err =>
212 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
216 // Try to retrieve the span of the function signature and generate a new message with
217 // a local type parameter
218 let sugg_msg = "try using a local type parameter instead";
219 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
220 // Suggest the modification to the user
221 err.span_suggestion(sugg_span,
224 } else if let Some(sp) = cm.generate_fn_name_span(span) {
225 err.span_label(sp, "try adding a local type parameter in this method instead");
227 err.help("try using a local type parameter instead");
232 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
233 let mut err = struct_span_err!(resolver.session,
236 "the name `{}` is already used for a type parameter \
237 in this type parameter list",
239 err.span_label(span, "already used");
240 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
243 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
244 let mut err = struct_span_err!(resolver.session,
247 "method `{}` is not a member of trait `{}`",
250 err.span_label(span, format!("not a member of trait `{}`", trait_));
253 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
254 let mut err = struct_span_err!(resolver.session,
257 "type `{}` is not a member of trait `{}`",
260 err.span_label(span, format!("not a member of trait `{}`", trait_));
263 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
264 let mut err = struct_span_err!(resolver.session,
267 "const `{}` is not a member of trait `{}`",
270 err.span_label(span, format!("not a member of trait `{}`", trait_));
273 ResolutionError::VariableNotBoundInPattern(binding_error) => {
274 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
275 let msp = MultiSpan::from_spans(target_sp.clone());
276 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
277 let mut err = resolver.session.struct_span_err_with_code(
280 DiagnosticId::Error("E0408".into()),
282 for sp in target_sp {
283 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
285 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
286 for sp in origin_sp {
287 err.span_label(sp, "variable not in all patterns");
291 ResolutionError::VariableBoundWithDifferentMode(variable_name,
292 first_binding_span) => {
293 let mut err = struct_span_err!(resolver.session,
296 "variable `{}` is bound in inconsistent \
297 ways within the same match arm",
299 err.span_label(span, "bound in different ways");
300 err.span_label(first_binding_span, "first binding");
303 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
304 let mut err = struct_span_err!(resolver.session,
307 "identifier `{}` is bound more than once in this parameter list",
309 err.span_label(span, "used as parameter more than once");
312 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
313 let mut err = struct_span_err!(resolver.session,
316 "identifier `{}` is bound more than once in the same pattern",
318 err.span_label(span, "used in a pattern more than once");
321 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
322 let mut err = struct_span_err!(resolver.session,
325 "use of undeclared label `{}`",
327 if let Some(lev_candidate) = lev_candidate {
328 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
330 err.span_label(span, format!("undeclared label `{}`", name));
334 ResolutionError::SelfImportsOnlyAllowedWithin => {
335 struct_span_err!(resolver.session,
339 "`self` imports are only allowed within a { } list")
341 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
342 let mut err = struct_span_err!(resolver.session, span, E0430,
343 "`self` import can only appear once in an import list");
344 err.span_label(span, "can only appear once in an import list");
347 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
348 let mut err = struct_span_err!(resolver.session, span, E0431,
349 "`self` import can only appear in an import list with \
350 a non-empty prefix");
351 err.span_label(span, "can only appear in an import list with a non-empty prefix");
354 ResolutionError::UnresolvedImport(name) => {
355 let (span, msg) = match name {
356 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
357 None => (span, "unresolved import".to_owned()),
359 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
360 if let Some((_, _, p)) = name {
361 err.span_label(span, p);
365 ResolutionError::FailedToResolve(msg) => {
366 let mut err = struct_span_err!(resolver.session, span, E0433,
367 "failed to resolve. {}", msg);
368 err.span_label(span, msg);
371 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
372 let mut err = struct_span_err!(resolver.session,
376 "can't capture dynamic environment in a fn item");
377 err.help("use the `|| { ... }` closure form instead");
380 ResolutionError::AttemptToUseNonConstantValueInConstant => {
381 let mut err = struct_span_err!(resolver.session, span, E0435,
382 "attempt to use a non-constant value in a constant");
383 err.span_label(span, "non-constant value");
386 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
387 let shadows_what = PathResolution::new(binding.def()).kind_name();
388 let mut err = struct_span_err!(resolver.session,
391 "{}s cannot shadow {}s", what_binding, shadows_what);
392 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
393 let participle = if binding.is_import() { "imported" } else { "defined" };
394 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
395 err.span_label(binding.span, msg);
398 ResolutionError::ForwardDeclaredTyParam => {
399 let mut err = struct_span_err!(resolver.session, span, E0128,
400 "type parameters with a default cannot use \
401 forward declared identifiers");
402 err.span_label(span, format!("defaulted type parameters cannot be forward declared"));
408 /// Adjust the impl span so that just the `impl` keyword is taken by removing
409 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
410 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
412 /// Attention: The method used is very fragile since it essentially duplicates the work of the
413 /// parser. If you need to use this function or something similar, please consider updating the
414 /// codemap functions and this function to something more robust.
415 fn reduce_impl_span_to_impl_keyword(cm: &CodeMap, impl_span: Span) -> Span {
416 let impl_span = cm.span_until_char(impl_span, '<');
417 let impl_span = cm.span_until_whitespace(impl_span);
421 #[derive(Copy, Clone, Debug)]
424 binding_mode: BindingMode,
427 /// Map from the name in a pattern to its binding mode.
428 type BindingMap = FxHashMap<Ident, BindingInfo>;
430 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
441 fn descr(self) -> &'static str {
443 PatternSource::Match => "match binding",
444 PatternSource::IfLet => "if let binding",
445 PatternSource::WhileLet => "while let binding",
446 PatternSource::Let => "let binding",
447 PatternSource::For => "for binding",
448 PatternSource::FnParam => "function parameter",
453 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
454 enum AliasPossibility {
459 #[derive(Copy, Clone, Debug)]
460 enum PathSource<'a> {
461 // Type paths `Path`.
463 // Trait paths in bounds or impls.
464 Trait(AliasPossibility),
465 // Expression paths `path`, with optional parent context.
466 Expr(Option<&'a Expr>),
467 // Paths in path patterns `Path`.
469 // Paths in struct expressions and patterns `Path { .. }`.
471 // Paths in tuple struct patterns `Path(..)`.
473 // `m::A::B` in `<T as m::A>::B::C`.
474 TraitItem(Namespace),
475 // Path in `pub(path)`
477 // Path in `use a::b::{...};`
481 impl<'a> PathSource<'a> {
482 fn namespace(self) -> Namespace {
484 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
485 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
486 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
487 PathSource::TraitItem(ns) => ns,
491 fn global_by_default(self) -> bool {
493 PathSource::Visibility | PathSource::ImportPrefix => true,
494 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
495 PathSource::Struct | PathSource::TupleStruct |
496 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
500 fn defer_to_typeck(self) -> bool {
502 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
503 PathSource::Struct | PathSource::TupleStruct => true,
504 PathSource::Trait(_) | PathSource::TraitItem(..) |
505 PathSource::Visibility | PathSource::ImportPrefix => false,
509 fn descr_expected(self) -> &'static str {
511 PathSource::Type => "type",
512 PathSource::Trait(_) => "trait",
513 PathSource::Pat => "unit struct/variant or constant",
514 PathSource::Struct => "struct, variant or union type",
515 PathSource::TupleStruct => "tuple struct/variant",
516 PathSource::Visibility => "module",
517 PathSource::ImportPrefix => "module or enum",
518 PathSource::TraitItem(ns) => match ns {
519 TypeNS => "associated type",
520 ValueNS => "method or associated constant",
521 MacroNS => bug!("associated macro"),
523 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
524 // "function" here means "anything callable" rather than `Def::Fn`,
525 // this is not precise but usually more helpful than just "value".
526 Some(&ExprKind::Call(..)) => "function",
532 fn is_expected(self, def: Def) -> bool {
534 PathSource::Type => match def {
535 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
536 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
537 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
538 Def::Existential(..) |
539 Def::TyForeign(..) => true,
542 PathSource::Trait(AliasPossibility::No) => match def {
543 Def::Trait(..) => true,
546 PathSource::Trait(AliasPossibility::Maybe) => match def {
547 Def::Trait(..) => true,
548 Def::TraitAlias(..) => true,
551 PathSource::Expr(..) => match def {
552 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
553 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
554 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
555 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
558 PathSource::Pat => match def {
559 Def::StructCtor(_, CtorKind::Const) |
560 Def::VariantCtor(_, CtorKind::Const) |
561 Def::Const(..) | Def::AssociatedConst(..) => true,
564 PathSource::TupleStruct => match def {
565 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
568 PathSource::Struct => match def {
569 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
570 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
573 PathSource::TraitItem(ns) => match def {
574 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
575 Def::AssociatedTy(..) if ns == TypeNS => true,
578 PathSource::ImportPrefix => match def {
579 Def::Mod(..) | Def::Enum(..) => true,
582 PathSource::Visibility => match def {
583 Def::Mod(..) => true,
589 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
590 __diagnostic_used!(E0404);
591 __diagnostic_used!(E0405);
592 __diagnostic_used!(E0412);
593 __diagnostic_used!(E0422);
594 __diagnostic_used!(E0423);
595 __diagnostic_used!(E0425);
596 __diagnostic_used!(E0531);
597 __diagnostic_used!(E0532);
598 __diagnostic_used!(E0573);
599 __diagnostic_used!(E0574);
600 __diagnostic_used!(E0575);
601 __diagnostic_used!(E0576);
602 __diagnostic_used!(E0577);
603 __diagnostic_used!(E0578);
604 match (self, has_unexpected_resolution) {
605 (PathSource::Trait(_), true) => "E0404",
606 (PathSource::Trait(_), false) => "E0405",
607 (PathSource::Type, true) => "E0573",
608 (PathSource::Type, false) => "E0412",
609 (PathSource::Struct, true) => "E0574",
610 (PathSource::Struct, false) => "E0422",
611 (PathSource::Expr(..), true) => "E0423",
612 (PathSource::Expr(..), false) => "E0425",
613 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
614 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
615 (PathSource::TraitItem(..), true) => "E0575",
616 (PathSource::TraitItem(..), false) => "E0576",
617 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
618 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
623 struct UsePlacementFinder {
624 target_module: NodeId,
629 impl UsePlacementFinder {
630 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
631 let mut finder = UsePlacementFinder {
636 visit::walk_crate(&mut finder, krate);
637 (finder.span, finder.found_use)
641 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
644 module: &'tcx ast::Mod,
646 _: &[ast::Attribute],
649 if self.span.is_some() {
652 if node_id != self.target_module {
653 visit::walk_mod(self, module);
656 // find a use statement
657 for item in &module.items {
659 ItemKind::Use(..) => {
660 // don't suggest placing a use before the prelude
661 // import or other generated ones
662 if item.span.ctxt().outer().expn_info().is_none() {
663 self.span = Some(item.span.shrink_to_lo());
664 self.found_use = true;
668 // don't place use before extern crate
669 ItemKind::ExternCrate(_) => {}
670 // but place them before the first other item
671 _ => if self.span.map_or(true, |span| item.span < span ) {
672 if item.span.ctxt().outer().expn_info().is_none() {
673 // don't insert between attributes and an item
674 if item.attrs.is_empty() {
675 self.span = Some(item.span.shrink_to_lo());
677 // find the first attribute on the item
678 for attr in &item.attrs {
679 if self.span.map_or(true, |span| attr.span < span) {
680 self.span = Some(attr.span.shrink_to_lo());
691 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
692 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
693 fn visit_item(&mut self, item: &'tcx Item) {
694 self.resolve_item(item);
696 fn visit_arm(&mut self, arm: &'tcx Arm) {
697 self.resolve_arm(arm);
699 fn visit_block(&mut self, block: &'tcx Block) {
700 self.resolve_block(block);
702 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
703 self.with_constant_rib(|this| {
704 visit::walk_anon_const(this, constant);
707 fn visit_expr(&mut self, expr: &'tcx Expr) {
708 self.resolve_expr(expr, None);
710 fn visit_local(&mut self, local: &'tcx Local) {
711 self.resolve_local(local);
713 fn visit_ty(&mut self, ty: &'tcx Ty) {
715 TyKind::Path(ref qself, ref path) => {
716 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
718 TyKind::ImplicitSelf => {
719 let self_ty = keywords::SelfType.ident();
720 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
721 .map_or(Def::Err, |d| d.def());
722 self.record_def(ty.id, PathResolution::new(def));
726 visit::walk_ty(self, ty);
728 fn visit_poly_trait_ref(&mut self,
729 tref: &'tcx ast::PolyTraitRef,
730 m: &'tcx ast::TraitBoundModifier) {
731 self.smart_resolve_path(tref.trait_ref.ref_id, None,
732 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
733 visit::walk_poly_trait_ref(self, tref, m);
735 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
736 let type_parameters = match foreign_item.node {
737 ForeignItemKind::Fn(_, ref generics) => {
738 HasTypeParameters(generics, ItemRibKind)
740 ForeignItemKind::Static(..) => NoTypeParameters,
741 ForeignItemKind::Ty => NoTypeParameters,
742 ForeignItemKind::Macro(..) => NoTypeParameters,
744 self.with_type_parameter_rib(type_parameters, |this| {
745 visit::walk_foreign_item(this, foreign_item);
748 fn visit_fn(&mut self,
749 function_kind: FnKind<'tcx>,
750 declaration: &'tcx FnDecl,
754 let (rib_kind, asyncness) = match function_kind {
755 FnKind::ItemFn(_, ref header, ..) =>
756 (ItemRibKind, header.asyncness),
757 FnKind::Method(_, ref sig, _, _) =>
758 (TraitOrImplItemRibKind, sig.header.asyncness),
759 FnKind::Closure(_) =>
760 // Async closures aren't resolved through `visit_fn`-- they're
761 // processed separately
762 (ClosureRibKind(node_id), IsAsync::NotAsync),
765 // Create a value rib for the function.
766 self.ribs[ValueNS].push(Rib::new(rib_kind));
768 // Create a label rib for the function.
769 self.label_ribs.push(Rib::new(rib_kind));
771 // Add each argument to the rib.
772 let mut bindings_list = FxHashMap();
773 for argument in &declaration.inputs {
774 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
776 self.visit_ty(&argument.ty);
778 debug!("(resolving function) recorded argument");
780 visit::walk_fn_ret_ty(self, &declaration.output);
782 // Resolve the function body, potentially inside the body of an async closure
783 if let IsAsync::Async { closure_id, .. } = asyncness {
784 let rib_kind = ClosureRibKind(closure_id);
785 self.ribs[ValueNS].push(Rib::new(rib_kind));
786 self.label_ribs.push(Rib::new(rib_kind));
789 match function_kind {
790 FnKind::ItemFn(.., body) |
791 FnKind::Method(.., body) => {
792 self.visit_block(body);
794 FnKind::Closure(body) => {
795 self.visit_expr(body);
799 // Leave the body of the async closure
800 if asyncness.is_async() {
801 self.label_ribs.pop();
802 self.ribs[ValueNS].pop();
805 debug!("(resolving function) leaving function");
807 self.label_ribs.pop();
808 self.ribs[ValueNS].pop();
810 fn visit_generics(&mut self, generics: &'tcx Generics) {
811 // For type parameter defaults, we have to ban access
812 // to following type parameters, as the Substs can only
813 // provide previous type parameters as they're built. We
814 // put all the parameters on the ban list and then remove
815 // them one by one as they are processed and become available.
816 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
817 let mut found_default = false;
818 default_ban_rib.bindings.extend(generics.params.iter()
819 .filter_map(|param| match param.kind {
820 GenericParamKind::Lifetime { .. } => None,
821 GenericParamKind::Type { ref default, .. } => {
822 if found_default || default.is_some() {
823 found_default = true;
824 return Some((Ident::with_empty_ctxt(param.ident.name), Def::Err));
830 for param in &generics.params {
832 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
833 GenericParamKind::Type { ref default, .. } => {
834 for bound in ¶m.bounds {
835 self.visit_param_bound(bound);
838 if let Some(ref ty) = default {
839 self.ribs[TypeNS].push(default_ban_rib);
841 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
844 // Allow all following defaults to refer to this type parameter.
845 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
849 for p in &generics.where_clause.predicates {
850 self.visit_where_predicate(p);
855 #[derive(Copy, Clone)]
856 enum TypeParameters<'a, 'b> {
858 HasTypeParameters(// Type parameters.
861 // The kind of the rib used for type parameters.
865 /// The rib kind controls the translation of local
866 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
867 #[derive(Copy, Clone, Debug)]
869 /// No translation needs to be applied.
872 /// We passed through a closure scope at the given node ID.
873 /// Translate upvars as appropriate.
874 ClosureRibKind(NodeId /* func id */),
876 /// We passed through an impl or trait and are now in one of its
877 /// methods or associated types. Allow references to ty params that impl or trait
878 /// binds. Disallow any other upvars (including other ty params that are
880 TraitOrImplItemRibKind,
882 /// We passed through an item scope. Disallow upvars.
885 /// We're in a constant item. Can't refer to dynamic stuff.
888 /// We passed through a module.
889 ModuleRibKind(Module<'a>),
891 /// We passed through a `macro_rules!` statement
892 MacroDefinition(DefId),
894 /// All bindings in this rib are type parameters that can't be used
895 /// from the default of a type parameter because they're not declared
896 /// before said type parameter. Also see the `visit_generics` override.
897 ForwardTyParamBanRibKind,
902 /// A rib represents a scope names can live in. Note that these appear in many places, not just
903 /// around braces. At any place where the list of accessible names (of the given namespace)
904 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
905 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
908 /// Different [rib kinds](enum.RibKind) are transparent for different names.
910 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
911 /// resolving, the name is looked up from inside out.
914 bindings: FxHashMap<Ident, Def>,
919 fn new(kind: RibKind<'a>) -> Rib<'a> {
921 bindings: FxHashMap(),
927 /// An intermediate resolution result.
929 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
930 /// items are visible in their whole block, while defs only from the place they are defined
932 enum LexicalScopeBinding<'a> {
933 Item(&'a NameBinding<'a>),
937 impl<'a> LexicalScopeBinding<'a> {
938 fn item(self) -> Option<&'a NameBinding<'a>> {
940 LexicalScopeBinding::Item(binding) => Some(binding),
945 fn def(self) -> Def {
947 LexicalScopeBinding::Item(binding) => binding.def(),
948 LexicalScopeBinding::Def(def) => def,
953 #[derive(Clone, Debug)]
954 enum PathResult<'a> {
956 NonModule(PathResolution),
958 Failed(Span, String, bool /* is the error from the last segment? */),
962 /// An anonymous module, eg. just a block.
967 /// { // This is an anonymous module
968 /// f(); // This resolves to (2) as we are inside the block.
971 /// f(); // Resolves to (1)
975 /// Any module with a name.
979 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
980 /// * A trait or an enum (it implicitly contains associated types, methods and variant
985 /// One node in the tree of modules.
986 pub struct ModuleData<'a> {
987 parent: Option<Module<'a>>,
990 // The def id of the closest normal module (`mod`) ancestor (including this module).
991 normal_ancestor_id: DefId,
993 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
994 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, MacroKind, Option<Def>)>>,
995 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
997 // Macro invocations that can expand into items in this module.
998 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1000 no_implicit_prelude: bool,
1002 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1003 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1005 // Used to memoize the traits in this module for faster searches through all traits in scope.
1006 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1008 // Whether this module is populated. If not populated, any attempt to
1009 // access the children must be preceded with a
1010 // `populate_module_if_necessary` call.
1011 populated: Cell<bool>,
1013 /// Span of the module itself. Used for error reporting.
1019 type Module<'a> = &'a ModuleData<'a>;
1021 impl<'a> ModuleData<'a> {
1022 fn new(parent: Option<Module<'a>>,
1024 normal_ancestor_id: DefId,
1026 span: Span) -> Self {
1031 resolutions: RefCell::new(FxHashMap()),
1032 legacy_macro_resolutions: RefCell::new(Vec::new()),
1033 macro_resolutions: RefCell::new(Vec::new()),
1034 unresolved_invocations: RefCell::new(FxHashSet()),
1035 no_implicit_prelude: false,
1036 glob_importers: RefCell::new(Vec::new()),
1037 globs: RefCell::new(Vec::new()),
1038 traits: RefCell::new(None),
1039 populated: Cell::new(normal_ancestor_id.is_local()),
1045 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1046 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1047 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1051 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1052 let resolutions = self.resolutions.borrow();
1053 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1054 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1055 for &(&(ident, ns), &resolution) in resolutions.iter() {
1056 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1060 fn def(&self) -> Option<Def> {
1062 ModuleKind::Def(def, _) => Some(def),
1067 fn def_id(&self) -> Option<DefId> {
1068 self.def().as_ref().map(Def::def_id)
1071 // `self` resolves to the first module ancestor that `is_normal`.
1072 fn is_normal(&self) -> bool {
1074 ModuleKind::Def(Def::Mod(_), _) => true,
1079 fn is_trait(&self) -> bool {
1081 ModuleKind::Def(Def::Trait(_), _) => true,
1086 fn is_local(&self) -> bool {
1087 self.normal_ancestor_id.is_local()
1090 fn nearest_item_scope(&'a self) -> Module<'a> {
1091 if self.is_trait() { self.parent.unwrap() } else { self }
1095 impl<'a> fmt::Debug for ModuleData<'a> {
1096 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1097 write!(f, "{:?}", self.def())
1101 /// Records a possibly-private value, type, or module definition.
1102 #[derive(Clone, Debug)]
1103 pub struct NameBinding<'a> {
1104 kind: NameBindingKind<'a>,
1107 vis: ty::Visibility,
1110 pub trait ToNameBinding<'a> {
1111 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1114 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1115 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1120 #[derive(Clone, Debug)]
1121 enum NameBindingKind<'a> {
1125 binding: &'a NameBinding<'a>,
1126 directive: &'a ImportDirective<'a>,
1130 b1: &'a NameBinding<'a>,
1131 b2: &'a NameBinding<'a>,
1135 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1137 struct UseError<'a> {
1138 err: DiagnosticBuilder<'a>,
1139 /// Attach `use` statements for these candidates
1140 candidates: Vec<ImportSuggestion>,
1141 /// The node id of the module to place the use statements in
1143 /// Whether the diagnostic should state that it's "better"
1147 struct AmbiguityError<'a> {
1151 b1: &'a NameBinding<'a>,
1152 b2: &'a NameBinding<'a>,
1155 impl<'a> NameBinding<'a> {
1156 fn module(&self) -> Option<Module<'a>> {
1158 NameBindingKind::Module(module) => Some(module),
1159 NameBindingKind::Import { binding, .. } => binding.module(),
1164 fn def(&self) -> Def {
1166 NameBindingKind::Def(def) => def,
1167 NameBindingKind::Module(module) => module.def().unwrap(),
1168 NameBindingKind::Import { binding, .. } => binding.def(),
1169 NameBindingKind::Ambiguity { .. } => Def::Err,
1173 fn def_ignoring_ambiguity(&self) -> Def {
1175 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1176 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1181 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Lrc<SyntaxExtension> {
1182 resolver.get_macro(self.def_ignoring_ambiguity())
1185 // We sometimes need to treat variants as `pub` for backwards compatibility
1186 fn pseudo_vis(&self) -> ty::Visibility {
1187 if self.is_variant() && self.def().def_id().is_local() {
1188 ty::Visibility::Public
1194 fn is_variant(&self) -> bool {
1196 NameBindingKind::Def(Def::Variant(..)) |
1197 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1202 fn is_extern_crate(&self) -> bool {
1204 NameBindingKind::Import {
1205 directive: &ImportDirective {
1206 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1213 fn is_import(&self) -> bool {
1215 NameBindingKind::Import { .. } => true,
1220 fn is_renamed_extern_crate(&self) -> bool {
1221 if let NameBindingKind::Import { directive, ..} = self.kind {
1222 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1229 fn is_glob_import(&self) -> bool {
1231 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1232 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1237 fn is_importable(&self) -> bool {
1239 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1244 fn is_macro_def(&self) -> bool {
1246 NameBindingKind::Def(Def::Macro(..)) => true,
1251 fn descr(&self) -> &'static str {
1252 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1256 /// Interns the names of the primitive types.
1258 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1259 /// special handling, since they have no place of origin.
1260 struct PrimitiveTypeTable {
1261 primitive_types: FxHashMap<Name, PrimTy>,
1264 impl PrimitiveTypeTable {
1265 fn new() -> PrimitiveTypeTable {
1266 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1268 table.intern("bool", TyBool);
1269 table.intern("char", TyChar);
1270 table.intern("f32", TyFloat(FloatTy::F32));
1271 table.intern("f64", TyFloat(FloatTy::F64));
1272 table.intern("isize", TyInt(IntTy::Isize));
1273 table.intern("i8", TyInt(IntTy::I8));
1274 table.intern("i16", TyInt(IntTy::I16));
1275 table.intern("i32", TyInt(IntTy::I32));
1276 table.intern("i64", TyInt(IntTy::I64));
1277 table.intern("i128", TyInt(IntTy::I128));
1278 table.intern("str", TyStr);
1279 table.intern("usize", TyUint(UintTy::Usize));
1280 table.intern("u8", TyUint(UintTy::U8));
1281 table.intern("u16", TyUint(UintTy::U16));
1282 table.intern("u32", TyUint(UintTy::U32));
1283 table.intern("u64", TyUint(UintTy::U64));
1284 table.intern("u128", TyUint(UintTy::U128));
1288 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1289 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1293 /// The main resolver class.
1295 /// This is the visitor that walks the whole crate.
1296 pub struct Resolver<'a> {
1297 session: &'a Session,
1298 cstore: &'a dyn CrateStore,
1300 pub definitions: Definitions,
1302 graph_root: Module<'a>,
1304 prelude: Option<Module<'a>>,
1305 extern_prelude: FxHashSet<Name>,
1307 /// n.b. This is used only for better diagnostics, not name resolution itself.
1308 has_self: FxHashSet<DefId>,
1310 /// Names of fields of an item `DefId` accessible with dot syntax.
1311 /// Used for hints during error reporting.
1312 field_names: FxHashMap<DefId, Vec<Name>>,
1314 /// All imports known to succeed or fail.
1315 determined_imports: Vec<&'a ImportDirective<'a>>,
1317 /// All non-determined imports.
1318 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1320 /// The module that represents the current item scope.
1321 current_module: Module<'a>,
1323 /// The current set of local scopes for types and values.
1324 /// FIXME #4948: Reuse ribs to avoid allocation.
1325 ribs: PerNS<Vec<Rib<'a>>>,
1327 /// The current set of local scopes, for labels.
1328 label_ribs: Vec<Rib<'a>>,
1330 /// The trait that the current context can refer to.
1331 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1333 /// The current self type if inside an impl (used for better errors).
1334 current_self_type: Option<Ty>,
1336 /// The idents for the primitive types.
1337 primitive_type_table: PrimitiveTypeTable,
1340 import_map: ImportMap,
1341 pub freevars: FreevarMap,
1342 freevars_seen: NodeMap<NodeMap<usize>>,
1343 pub export_map: ExportMap,
1344 pub trait_map: TraitMap,
1346 /// A map from nodes to anonymous modules.
1347 /// Anonymous modules are pseudo-modules that are implicitly created around items
1348 /// contained within blocks.
1350 /// For example, if we have this:
1358 /// There will be an anonymous module created around `g` with the ID of the
1359 /// entry block for `f`.
1360 block_map: NodeMap<Module<'a>>,
1361 module_map: FxHashMap<DefId, Module<'a>>,
1362 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1364 pub make_glob_map: bool,
1365 /// Maps imports to the names of items actually imported (this actually maps
1366 /// all imports, but only glob imports are actually interesting).
1367 pub glob_map: GlobMap,
1369 used_imports: FxHashSet<(NodeId, Namespace)>,
1370 pub maybe_unused_trait_imports: NodeSet,
1371 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1373 /// A list of labels as of yet unused. Labels will be removed from this map when
1374 /// they are used (in a `break` or `continue` statement)
1375 pub unused_labels: FxHashMap<NodeId, Span>,
1377 /// privacy errors are delayed until the end in order to deduplicate them
1378 privacy_errors: Vec<PrivacyError<'a>>,
1379 /// ambiguity errors are delayed for deduplication
1380 ambiguity_errors: Vec<AmbiguityError<'a>>,
1381 /// `use` injections are delayed for better placement and deduplication
1382 use_injections: Vec<UseError<'a>>,
1383 /// `use` injections for proc macros wrongly imported with #[macro_use]
1384 proc_mac_errors: Vec<macros::ProcMacError>,
1386 gated_errors: FxHashSet<Span>,
1387 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1389 arenas: &'a ResolverArenas<'a>,
1390 dummy_binding: &'a NameBinding<'a>,
1391 /// true if `#![feature(use_extern_macros)]`
1392 use_extern_macros: bool,
1394 crate_loader: &'a mut dyn CrateLoader,
1395 macro_names: FxHashSet<Ident>,
1396 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1397 pub all_macros: FxHashMap<Name, Def>,
1398 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1399 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1400 macro_defs: FxHashMap<Mark, DefId>,
1401 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1402 macro_exports: Vec<Export>,
1403 pub whitelisted_legacy_custom_derives: Vec<Name>,
1404 pub found_unresolved_macro: bool,
1406 /// List of crate local macros that we need to warn about as being unused.
1407 /// Right now this only includes macro_rules! macros, and macros 2.0.
1408 unused_macros: FxHashSet<DefId>,
1410 /// Maps the `Mark` of an expansion to its containing module or block.
1411 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1413 /// Avoid duplicated errors for "name already defined".
1414 name_already_seen: FxHashMap<Name, Span>,
1416 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1417 warned_proc_macros: FxHashSet<Name>,
1419 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1421 /// This table maps struct IDs into struct constructor IDs,
1422 /// it's not used during normal resolution, only for better error reporting.
1423 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1425 /// Only used for better errors on `fn(): fn()`
1426 current_type_ascription: Vec<Span>,
1428 injected_crate: Option<Module<'a>>,
1430 /// Only supposed to be used by rustdoc, otherwise should be false.
1431 pub ignore_extern_prelude_feature: bool,
1434 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1435 pub struct ResolverArenas<'a> {
1436 modules: arena::TypedArena<ModuleData<'a>>,
1437 local_modules: RefCell<Vec<Module<'a>>>,
1438 name_bindings: arena::TypedArena<NameBinding<'a>>,
1439 import_directives: arena::TypedArena<ImportDirective<'a>>,
1440 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1441 invocation_data: arena::TypedArena<InvocationData<'a>>,
1442 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1445 impl<'a> ResolverArenas<'a> {
1446 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1447 let module = self.modules.alloc(module);
1448 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1449 self.local_modules.borrow_mut().push(module);
1453 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1454 self.local_modules.borrow()
1456 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1457 self.name_bindings.alloc(name_binding)
1459 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1460 -> &'a ImportDirective {
1461 self.import_directives.alloc(import_directive)
1463 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1464 self.name_resolutions.alloc(Default::default())
1466 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1467 -> &'a InvocationData<'a> {
1468 self.invocation_data.alloc(expansion_data)
1470 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1471 self.legacy_bindings.alloc(binding)
1475 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1476 fn parent(self, id: DefId) -> Option<DefId> {
1478 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1479 _ => self.cstore.def_key(id).parent,
1480 }.map(|index| DefId { index, ..id })
1484 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1485 /// the resolver is no longer needed as all the relevant information is inline.
1486 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1487 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1488 self.resolve_hir_path_cb(path, is_value,
1489 |resolver, span, error| resolve_error(resolver, span, error))
1492 fn resolve_str_path(
1495 crate_root: Option<&str>,
1496 components: &[&str],
1497 args: Option<P<hir::GenericArgs>>,
1500 let mut segments = iter::once(keywords::CrateRoot.ident())
1502 crate_root.into_iter()
1503 .chain(components.iter().cloned())
1504 .map(Ident::from_str)
1505 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1507 if let Some(args) = args {
1508 let ident = segments.last().unwrap().ident;
1509 *segments.last_mut().unwrap() = hir::PathSegment {
1516 let mut path = hir::Path {
1519 segments: segments.into(),
1522 self.resolve_hir_path(&mut path, is_value);
1526 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1527 self.def_map.get(&id).cloned()
1530 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1531 self.import_map.get(&id).cloned().unwrap_or_default()
1534 fn definitions(&mut self) -> &mut Definitions {
1535 &mut self.definitions
1539 impl<'a> Resolver<'a> {
1540 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1541 /// isn't something that can be returned because it can't be made to live that long,
1542 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1543 /// just that an error occurred.
1544 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1545 -> Result<hir::Path, ()> {
1547 let mut errored = false;
1549 let mut path = if path_str.starts_with("::") {
1553 segments: iter::once(keywords::CrateRoot.ident()).chain({
1554 path_str.split("::").skip(1).map(Ident::from_str)
1555 }).map(hir::PathSegment::from_ident).collect(),
1561 segments: path_str.split("::").map(Ident::from_str)
1562 .map(hir::PathSegment::from_ident).collect(),
1565 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1566 if errored || path.def == Def::Err {
1573 /// resolve_hir_path, but takes a callback in case there was an error
1574 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1575 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1577 let namespace = if is_value { ValueNS } else { TypeNS };
1578 let hir::Path { ref segments, span, ref mut def } = *path;
1579 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1580 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1581 match self.resolve_path(&path, Some(namespace), true, span, CrateLint::No) {
1582 PathResult::Module(module) => *def = module.def().unwrap(),
1583 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1584 *def = path_res.base_def(),
1585 PathResult::NonModule(..) => match self.resolve_path(
1592 PathResult::Failed(span, msg, _) => {
1593 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1597 PathResult::Indeterminate => unreachable!(),
1598 PathResult::Failed(span, msg, _) => {
1599 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1605 impl<'a> Resolver<'a> {
1606 pub fn new(session: &'a Session,
1607 cstore: &'a dyn CrateStore,
1610 make_glob_map: MakeGlobMap,
1611 crate_loader: &'a mut dyn CrateLoader,
1612 arenas: &'a ResolverArenas<'a>)
1614 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1615 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1616 let graph_root = arenas.alloc_module(ModuleData {
1617 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1618 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1620 let mut module_map = FxHashMap();
1621 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1623 let mut definitions = Definitions::new();
1624 DefCollector::new(&mut definitions, Mark::root())
1625 .collect_root(crate_name, session.local_crate_disambiguator());
1627 let mut extern_prelude: FxHashSet<Name> =
1628 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1629 if !attr::contains_name(&krate.attrs, "no_core") {
1630 if !attr::contains_name(&krate.attrs, "no_std") {
1631 extern_prelude.insert(Symbol::intern("std"));
1633 extern_prelude.insert(Symbol::intern("core"));
1637 let mut invocations = FxHashMap();
1638 invocations.insert(Mark::root(),
1639 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1641 let features = session.features_untracked();
1643 let mut macro_defs = FxHashMap();
1644 macro_defs.insert(Mark::root(), root_def_id);
1653 // The outermost module has def ID 0; this is not reflected in the
1659 has_self: FxHashSet(),
1660 field_names: FxHashMap(),
1662 determined_imports: Vec::new(),
1663 indeterminate_imports: Vec::new(),
1665 current_module: graph_root,
1667 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1668 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1669 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1671 label_ribs: Vec::new(),
1673 current_trait_ref: None,
1674 current_self_type: None,
1676 primitive_type_table: PrimitiveTypeTable::new(),
1679 import_map: NodeMap(),
1680 freevars: NodeMap(),
1681 freevars_seen: NodeMap(),
1682 export_map: FxHashMap(),
1683 trait_map: NodeMap(),
1685 block_map: NodeMap(),
1686 extern_module_map: FxHashMap(),
1688 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1689 glob_map: NodeMap(),
1691 used_imports: FxHashSet(),
1692 maybe_unused_trait_imports: NodeSet(),
1693 maybe_unused_extern_crates: Vec::new(),
1695 unused_labels: FxHashMap(),
1697 privacy_errors: Vec::new(),
1698 ambiguity_errors: Vec::new(),
1699 use_injections: Vec::new(),
1700 proc_mac_errors: Vec::new(),
1701 gated_errors: FxHashSet(),
1702 disallowed_shadowing: Vec::new(),
1705 dummy_binding: arenas.alloc_name_binding(NameBinding {
1706 kind: NameBindingKind::Def(Def::Err),
1707 expansion: Mark::root(),
1709 vis: ty::Visibility::Public,
1712 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1714 features.use_extern_macros || features.decl_macro,
1717 macro_names: FxHashSet(),
1718 global_macros: FxHashMap(),
1719 all_macros: FxHashMap(),
1720 lexical_macro_resolutions: Vec::new(),
1721 macro_map: FxHashMap(),
1722 macro_exports: Vec::new(),
1725 local_macro_def_scopes: FxHashMap(),
1726 name_already_seen: FxHashMap(),
1727 whitelisted_legacy_custom_derives: Vec::new(),
1728 warned_proc_macros: FxHashSet(),
1729 potentially_unused_imports: Vec::new(),
1730 struct_constructors: DefIdMap(),
1731 found_unresolved_macro: false,
1732 unused_macros: FxHashSet(),
1733 current_type_ascription: Vec::new(),
1734 injected_crate: None,
1735 ignore_extern_prelude_feature: false,
1739 pub fn arenas() -> ResolverArenas<'a> {
1741 modules: arena::TypedArena::new(),
1742 local_modules: RefCell::new(Vec::new()),
1743 name_bindings: arena::TypedArena::new(),
1744 import_directives: arena::TypedArena::new(),
1745 name_resolutions: arena::TypedArena::new(),
1746 invocation_data: arena::TypedArena::new(),
1747 legacy_bindings: arena::TypedArena::new(),
1751 /// Runs the function on each namespace.
1752 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1755 if self.use_extern_macros {
1760 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1762 match self.macro_defs.get(&ctxt.outer()) {
1763 Some(&def_id) => return def_id,
1764 None => ctxt.remove_mark(),
1769 /// Entry point to crate resolution.
1770 pub fn resolve_crate(&mut self, krate: &Crate) {
1771 ImportResolver { resolver: self }.finalize_imports();
1772 self.current_module = self.graph_root;
1773 self.finalize_current_module_macro_resolutions();
1775 visit::walk_crate(self, krate);
1777 check_unused::check_crate(self, krate);
1778 self.report_errors(krate);
1779 self.crate_loader.postprocess(krate);
1786 normal_ancestor_id: DefId,
1790 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1791 self.arenas.alloc_module(module)
1794 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1795 -> bool /* true if an error was reported */ {
1796 match binding.kind {
1797 NameBindingKind::Import { directive, binding, ref used }
1800 directive.used.set(true);
1801 self.used_imports.insert((directive.id, ns));
1802 self.add_to_glob_map(directive.id, ident);
1803 self.record_use(ident, ns, binding, span)
1805 NameBindingKind::Import { .. } => false,
1806 NameBindingKind::Ambiguity { b1, b2 } => {
1807 self.ambiguity_errors.push(AmbiguityError {
1808 span, name: ident.name, lexical: false, b1, b2,
1816 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1817 if self.make_glob_map {
1818 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1822 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1823 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1824 /// `ident` in the first scope that defines it (or None if no scopes define it).
1826 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1827 /// the items are defined in the block. For example,
1830 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1833 /// g(); // This resolves to the local variable `g` since it shadows the item.
1837 /// Invariant: This must only be called during main resolution, not during
1838 /// import resolution.
1839 fn resolve_ident_in_lexical_scope(&mut self,
1844 -> Option<LexicalScopeBinding<'a>> {
1846 ident.span = if ident.name == keywords::SelfType.name() {
1847 // FIXME(jseyfried) improve `Self` hygiene
1848 ident.span.with_ctxt(SyntaxContext::empty())
1853 ident = ident.modern_and_legacy();
1856 // Walk backwards up the ribs in scope.
1857 let mut module = self.graph_root;
1858 for i in (0 .. self.ribs[ns].len()).rev() {
1859 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1860 // The ident resolves to a type parameter or local variable.
1861 return Some(LexicalScopeBinding::Def(
1862 self.adjust_local_def(ns, i, def, record_used, path_span)
1866 module = match self.ribs[ns][i].kind {
1867 ModuleRibKind(module) => module,
1868 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1869 // If an invocation of this macro created `ident`, give up on `ident`
1870 // and switch to `ident`'s source from the macro definition.
1871 ident.span.remove_mark();
1877 let item = self.resolve_ident_in_module_unadjusted(
1878 module, ident, ns, false, record_used, path_span,
1880 if let Ok(binding) = item {
1881 // The ident resolves to an item.
1882 return Some(LexicalScopeBinding::Item(binding));
1886 ModuleKind::Block(..) => {}, // We can see through blocks
1891 ident.span = ident.span.modern();
1893 let (opt_module, poisoned) = if record_used {
1894 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span)
1896 (self.hygienic_lexical_parent(module, &mut ident.span), false)
1898 module = unwrap_or!(opt_module, break);
1899 let orig_current_module = self.current_module;
1900 self.current_module = module; // Lexical resolutions can never be a privacy error.
1901 let result = self.resolve_ident_in_module_unadjusted(
1902 module, ident, ns, false, record_used, path_span,
1904 self.current_module = orig_current_module;
1909 self.session.buffer_lint_with_diagnostic(
1910 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1911 CRATE_NODE_ID, ident.span,
1912 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1913 lint::builtin::BuiltinLintDiagnostics::
1914 ProcMacroDeriveResolutionFallback(ident.span),
1917 return Some(LexicalScopeBinding::Item(binding))
1919 _ if poisoned => break,
1920 Err(Undetermined) => return None,
1921 Err(Determined) => {}
1925 if !module.no_implicit_prelude {
1926 // `record_used` means that we don't try to load crates during speculative resolution
1927 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1928 if !self.session.features_untracked().extern_prelude &&
1929 !self.ignore_extern_prelude_feature {
1930 feature_err(&self.session.parse_sess, "extern_prelude",
1931 ident.span, GateIssue::Language,
1932 "access to extern crates through prelude is experimental").emit();
1935 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1936 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1937 self.populate_module_if_necessary(crate_root);
1939 let binding = (crate_root, ty::Visibility::Public,
1940 ident.span, Mark::root()).to_name_binding(self.arenas);
1941 return Some(LexicalScopeBinding::Item(binding));
1943 if let Some(prelude) = self.prelude {
1944 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(prelude, ident, ns,
1945 false, false, path_span) {
1946 return Some(LexicalScopeBinding::Item(binding));
1954 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
1955 -> Option<Module<'a>> {
1956 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
1957 return Some(self.macro_def_scope(span.remove_mark()));
1960 if let ModuleKind::Block(..) = module.kind {
1961 return Some(module.parent.unwrap());
1967 fn hygienic_lexical_parent_with_compatibility_fallback(
1968 &mut self, module: Module<'a>, span: &mut Span) -> (Option<Module<'a>>, /* poisoned */ bool
1970 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1971 return (module, false);
1974 // We need to support the next case under a deprecation warning
1977 // ---- begin: this comes from a proc macro derive
1978 // mod implementation_details {
1979 // // Note that `MyStruct` is not in scope here.
1980 // impl SomeTrait for MyStruct { ... }
1984 // So we have to fall back to the module's parent during lexical resolution in this case.
1985 if let Some(parent) = module.parent {
1986 // Inner module is inside the macro, parent module is outside of the macro.
1987 if module.expansion != parent.expansion &&
1988 module.expansion.is_descendant_of(parent.expansion) {
1989 // The macro is a proc macro derive
1990 if module.expansion.looks_like_proc_macro_derive() {
1991 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
1992 return (module.parent, true);
2001 fn resolve_ident_in_module(&mut self,
2005 ignore_unresolved_invocations: bool,
2008 -> Result<&'a NameBinding<'a>, Determinacy> {
2009 ident.span = ident.span.modern();
2010 let orig_current_module = self.current_module;
2011 if let Some(def) = ident.span.adjust(module.expansion) {
2012 self.current_module = self.macro_def_scope(def);
2014 let result = self.resolve_ident_in_module_unadjusted(
2015 module, ident, ns, ignore_unresolved_invocations, record_used, span,
2017 self.current_module = orig_current_module;
2021 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2022 let mut ctxt = ident.span.ctxt();
2023 let mark = if ident.name == keywords::DollarCrate.name() {
2024 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2025 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2026 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2027 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2028 // definitions actually produced by `macro` and `macro` definitions produced by
2029 // `macro_rules!`, but at least such configurations are not stable yet.
2030 ctxt = ctxt.modern_and_legacy();
2031 let mut iter = ctxt.marks().into_iter().rev().peekable();
2032 let mut result = None;
2033 // Find the last modern mark from the end if it exists.
2034 while let Some(&(mark, transparency)) = iter.peek() {
2035 if transparency == Transparency::Opaque {
2036 result = Some(mark);
2042 // Then find the last legacy mark from the end if it exists.
2043 for (mark, transparency) in iter {
2044 if transparency == Transparency::SemiTransparent {
2045 result = Some(mark);
2052 ctxt = ctxt.modern();
2053 ctxt.adjust(Mark::root())
2055 let module = match mark {
2056 Some(def) => self.macro_def_scope(def),
2057 None => return self.graph_root,
2059 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2062 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2063 let mut module = self.get_module(module.normal_ancestor_id);
2064 while module.span.ctxt().modern() != *ctxt {
2065 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2066 module = self.get_module(parent.normal_ancestor_id);
2073 // We maintain a list of value ribs and type ribs.
2075 // Simultaneously, we keep track of the current position in the module
2076 // graph in the `current_module` pointer. When we go to resolve a name in
2077 // the value or type namespaces, we first look through all the ribs and
2078 // then query the module graph. When we resolve a name in the module
2079 // namespace, we can skip all the ribs (since nested modules are not
2080 // allowed within blocks in Rust) and jump straight to the current module
2083 // Named implementations are handled separately. When we find a method
2084 // call, we consult the module node to find all of the implementations in
2085 // scope. This information is lazily cached in the module node. We then
2086 // generate a fake "implementation scope" containing all the
2087 // implementations thus found, for compatibility with old resolve pass.
2089 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2090 where F: FnOnce(&mut Resolver) -> T
2092 let id = self.definitions.local_def_id(id);
2093 let module = self.module_map.get(&id).cloned(); // clones a reference
2094 if let Some(module) = module {
2095 // Move down in the graph.
2096 let orig_module = replace(&mut self.current_module, module);
2097 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2098 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2100 self.finalize_current_module_macro_resolutions();
2103 self.current_module = orig_module;
2104 self.ribs[ValueNS].pop();
2105 self.ribs[TypeNS].pop();
2112 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2113 /// is returned by the given predicate function
2115 /// Stops after meeting a closure.
2116 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2117 where P: Fn(&Rib, Ident) -> Option<R>
2119 for rib in self.label_ribs.iter().rev() {
2122 // If an invocation of this macro created `ident`, give up on `ident`
2123 // and switch to `ident`'s source from the macro definition.
2124 MacroDefinition(def) => {
2125 if def == self.macro_def(ident.span.ctxt()) {
2126 ident.span.remove_mark();
2130 // Do not resolve labels across function boundary
2134 let r = pred(rib, ident);
2142 fn resolve_item(&mut self, item: &Item) {
2143 let name = item.ident.name;
2145 debug!("(resolving item) resolving {}", name);
2147 self.check_proc_macro_attrs(&item.attrs);
2150 ItemKind::Enum(_, ref generics) |
2151 ItemKind::Ty(_, ref generics) |
2152 ItemKind::Existential(_, ref generics) |
2153 ItemKind::Struct(_, ref generics) |
2154 ItemKind::Union(_, ref generics) |
2155 ItemKind::Fn(_, _, ref generics, _) => {
2156 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2157 |this| visit::walk_item(this, item));
2160 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2161 self.resolve_implementation(generics,
2167 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2168 // Create a new rib for the trait-wide type parameters.
2169 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2170 let local_def_id = this.definitions.local_def_id(item.id);
2171 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2172 this.visit_generics(generics);
2173 walk_list!(this, visit_param_bound, bounds);
2175 for trait_item in trait_items {
2176 this.check_proc_macro_attrs(&trait_item.attrs);
2178 let type_parameters = HasTypeParameters(&trait_item.generics,
2179 TraitOrImplItemRibKind);
2180 this.with_type_parameter_rib(type_parameters, |this| {
2181 match trait_item.node {
2182 TraitItemKind::Const(ref ty, ref default) => {
2185 // Only impose the restrictions of
2186 // ConstRibKind for an actual constant
2187 // expression in a provided default.
2188 if let Some(ref expr) = *default{
2189 this.with_constant_rib(|this| {
2190 this.visit_expr(expr);
2194 TraitItemKind::Method(_, _) => {
2195 visit::walk_trait_item(this, trait_item)
2197 TraitItemKind::Type(..) => {
2198 visit::walk_trait_item(this, trait_item)
2200 TraitItemKind::Macro(_) => {
2201 panic!("unexpanded macro in resolve!")
2210 ItemKind::TraitAlias(ref generics, ref bounds) => {
2211 // Create a new rib for the trait-wide type parameters.
2212 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2213 let local_def_id = this.definitions.local_def_id(item.id);
2214 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2215 this.visit_generics(generics);
2216 walk_list!(this, visit_param_bound, bounds);
2221 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2222 self.with_scope(item.id, |this| {
2223 visit::walk_item(this, item);
2227 ItemKind::Static(ref ty, _, ref expr) |
2228 ItemKind::Const(ref ty, ref expr) => {
2229 self.with_item_rib(|this| {
2231 this.with_constant_rib(|this| {
2232 this.visit_expr(expr);
2237 ItemKind::Use(ref use_tree) => {
2238 // Imports are resolved as global by default, add starting root segment.
2240 segments: use_tree.prefix.make_root().into_iter().collect(),
2241 span: use_tree.span,
2243 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2246 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2247 // do nothing, these are just around to be encoded
2250 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2254 /// For the most part, use trees are desugared into `ImportDirective` instances
2255 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2256 /// there is one special case we handle here: an empty nested import like
2257 /// `a::{b::{}}`, which desugares into...no import directives.
2258 fn resolve_use_tree(
2263 use_tree: &ast::UseTree,
2266 match use_tree.kind {
2267 ast::UseTreeKind::Nested(ref items) => {
2269 segments: prefix.segments
2271 .chain(use_tree.prefix.segments.iter())
2274 span: prefix.span.to(use_tree.prefix.span),
2277 if items.len() == 0 {
2278 // Resolve prefix of an import with empty braces (issue #28388).
2279 self.smart_resolve_path_with_crate_lint(
2283 PathSource::ImportPrefix,
2284 CrateLint::UsePath { root_id, root_span },
2287 for &(ref tree, nested_id) in items {
2288 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2292 ast::UseTreeKind::Simple(..) => {},
2293 ast::UseTreeKind::Glob => {},
2297 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2298 where F: FnOnce(&mut Resolver)
2300 match type_parameters {
2301 HasTypeParameters(generics, rib_kind) => {
2302 let mut function_type_rib = Rib::new(rib_kind);
2303 let mut seen_bindings = FxHashMap();
2304 generics.params.iter().for_each(|param| match param.kind {
2305 GenericParamKind::Lifetime { .. } => {}
2306 GenericParamKind::Type { .. } => {
2307 let ident = param.ident.modern();
2308 debug!("with_type_parameter_rib: {}", param.id);
2310 if seen_bindings.contains_key(&ident) {
2311 let span = seen_bindings.get(&ident).unwrap();
2312 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2316 resolve_error(self, param.ident.span, err);
2318 seen_bindings.entry(ident).or_insert(param.ident.span);
2320 // Plain insert (no renaming).
2321 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2322 function_type_rib.bindings.insert(ident, def);
2323 self.record_def(param.id, PathResolution::new(def));
2326 self.ribs[TypeNS].push(function_type_rib);
2329 NoTypeParameters => {
2336 if let HasTypeParameters(..) = type_parameters {
2337 self.ribs[TypeNS].pop();
2341 fn with_label_rib<F>(&mut self, f: F)
2342 where F: FnOnce(&mut Resolver)
2344 self.label_ribs.push(Rib::new(NormalRibKind));
2346 self.label_ribs.pop();
2349 fn with_item_rib<F>(&mut self, f: F)
2350 where F: FnOnce(&mut Resolver)
2352 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2353 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2355 self.ribs[TypeNS].pop();
2356 self.ribs[ValueNS].pop();
2359 fn with_constant_rib<F>(&mut self, f: F)
2360 where F: FnOnce(&mut Resolver)
2362 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2364 self.ribs[ValueNS].pop();
2367 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2368 where F: FnOnce(&mut Resolver) -> T
2370 // Handle nested impls (inside fn bodies)
2371 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2372 let result = f(self);
2373 self.current_self_type = previous_value;
2377 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2378 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2379 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2381 let mut new_val = None;
2382 let mut new_id = None;
2383 if let Some(trait_ref) = opt_trait_ref {
2384 let path: Vec<_> = trait_ref.path.segments.iter()
2385 .map(|seg| seg.ident)
2387 let def = self.smart_resolve_path_fragment(
2391 trait_ref.path.span,
2392 PathSource::Trait(AliasPossibility::No),
2393 CrateLint::SimplePath(trait_ref.ref_id),
2395 if def != Def::Err {
2396 new_id = Some(def.def_id());
2397 let span = trait_ref.path.span;
2398 if let PathResult::Module(module) = self.resolve_path(
2403 CrateLint::SimplePath(trait_ref.ref_id),
2405 new_val = Some((module, trait_ref.clone()));
2409 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2410 let result = f(self, new_id);
2411 self.current_trait_ref = original_trait_ref;
2415 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2416 where F: FnOnce(&mut Resolver)
2418 let mut self_type_rib = Rib::new(NormalRibKind);
2420 // plain insert (no renaming, types are not currently hygienic....)
2421 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2422 self.ribs[TypeNS].push(self_type_rib);
2424 self.ribs[TypeNS].pop();
2427 fn resolve_implementation(&mut self,
2428 generics: &Generics,
2429 opt_trait_reference: &Option<TraitRef>,
2432 impl_items: &[ImplItem]) {
2433 // If applicable, create a rib for the type parameters.
2434 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2435 // Dummy self type for better errors if `Self` is used in the trait path.
2436 this.with_self_rib(Def::SelfTy(None, None), |this| {
2437 // Resolve the trait reference, if necessary.
2438 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2439 let item_def_id = this.definitions.local_def_id(item_id);
2440 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2441 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2442 // Resolve type arguments in trait path
2443 visit::walk_trait_ref(this, trait_ref);
2445 // Resolve the self type.
2446 this.visit_ty(self_type);
2447 // Resolve the type parameters.
2448 this.visit_generics(generics);
2449 this.with_current_self_type(self_type, |this| {
2450 for impl_item in impl_items {
2451 this.check_proc_macro_attrs(&impl_item.attrs);
2452 this.resolve_visibility(&impl_item.vis);
2454 // We also need a new scope for the impl item type parameters.
2455 let type_parameters = HasTypeParameters(&impl_item.generics,
2456 TraitOrImplItemRibKind);
2457 this.with_type_parameter_rib(type_parameters, |this| {
2458 use self::ResolutionError::*;
2459 match impl_item.node {
2460 ImplItemKind::Const(..) => {
2461 // If this is a trait impl, ensure the const
2463 this.check_trait_item(impl_item.ident,
2466 |n, s| ConstNotMemberOfTrait(n, s));
2467 this.with_constant_rib(|this|
2468 visit::walk_impl_item(this, impl_item)
2471 ImplItemKind::Method(..) => {
2472 // If this is a trait impl, ensure the method
2474 this.check_trait_item(impl_item.ident,
2477 |n, s| MethodNotMemberOfTrait(n, s));
2479 visit::walk_impl_item(this, impl_item);
2481 ImplItemKind::Type(ref ty) => {
2482 // If this is a trait impl, ensure the type
2484 this.check_trait_item(impl_item.ident,
2487 |n, s| TypeNotMemberOfTrait(n, s));
2491 ImplItemKind::Existential(ref bounds) => {
2492 // If this is a trait impl, ensure the type
2494 this.check_trait_item(impl_item.ident,
2497 |n, s| TypeNotMemberOfTrait(n, s));
2499 for bound in bounds {
2500 this.visit_param_bound(bound);
2503 ImplItemKind::Macro(_) =>
2504 panic!("unexpanded macro in resolve!"),
2515 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2516 where F: FnOnce(Name, &str) -> ResolutionError
2518 // If there is a TraitRef in scope for an impl, then the method must be in the
2520 if let Some((module, _)) = self.current_trait_ref {
2521 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2522 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2523 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2528 fn resolve_local(&mut self, local: &Local) {
2529 // Resolve the type.
2530 walk_list!(self, visit_ty, &local.ty);
2532 // Resolve the initializer.
2533 walk_list!(self, visit_expr, &local.init);
2535 // Resolve the pattern.
2536 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2539 // build a map from pattern identifiers to binding-info's.
2540 // this is done hygienically. This could arise for a macro
2541 // that expands into an or-pattern where one 'x' was from the
2542 // user and one 'x' came from the macro.
2543 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2544 let mut binding_map = FxHashMap();
2546 pat.walk(&mut |pat| {
2547 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2548 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2549 Some(Def::Local(..)) => true,
2552 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2553 binding_map.insert(ident, binding_info);
2562 // check that all of the arms in an or-pattern have exactly the
2563 // same set of bindings, with the same binding modes for each.
2564 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2565 if pats.is_empty() {
2569 let mut missing_vars = FxHashMap();
2570 let mut inconsistent_vars = FxHashMap();
2571 for (i, p) in pats.iter().enumerate() {
2572 let map_i = self.binding_mode_map(&p);
2574 for (j, q) in pats.iter().enumerate() {
2579 let map_j = self.binding_mode_map(&q);
2580 for (&key, &binding_i) in &map_i {
2581 if map_j.len() == 0 { // Account for missing bindings when
2582 let binding_error = missing_vars // map_j has none.
2584 .or_insert(BindingError {
2586 origin: BTreeSet::new(),
2587 target: BTreeSet::new(),
2589 binding_error.origin.insert(binding_i.span);
2590 binding_error.target.insert(q.span);
2592 for (&key_j, &binding_j) in &map_j {
2593 match map_i.get(&key_j) {
2594 None => { // missing binding
2595 let binding_error = missing_vars
2597 .or_insert(BindingError {
2599 origin: BTreeSet::new(),
2600 target: BTreeSet::new(),
2602 binding_error.origin.insert(binding_j.span);
2603 binding_error.target.insert(p.span);
2605 Some(binding_i) => { // check consistent binding
2606 if binding_i.binding_mode != binding_j.binding_mode {
2609 .or_insert((binding_j.span, binding_i.span));
2617 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2618 missing_vars.sort();
2619 for (_, v) in missing_vars {
2621 *v.origin.iter().next().unwrap(),
2622 ResolutionError::VariableNotBoundInPattern(v));
2624 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2625 inconsistent_vars.sort();
2626 for (name, v) in inconsistent_vars {
2627 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2631 fn resolve_arm(&mut self, arm: &Arm) {
2632 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2634 let mut bindings_list = FxHashMap();
2635 for pattern in &arm.pats {
2636 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2639 // This has to happen *after* we determine which pat_idents are variants
2640 self.check_consistent_bindings(&arm.pats);
2642 walk_list!(self, visit_expr, &arm.guard);
2643 self.visit_expr(&arm.body);
2645 self.ribs[ValueNS].pop();
2648 fn resolve_block(&mut self, block: &Block) {
2649 debug!("(resolving block) entering block");
2650 // Move down in the graph, if there's an anonymous module rooted here.
2651 let orig_module = self.current_module;
2652 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2654 let mut num_macro_definition_ribs = 0;
2655 if let Some(anonymous_module) = anonymous_module {
2656 debug!("(resolving block) found anonymous module, moving down");
2657 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2658 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2659 self.current_module = anonymous_module;
2660 self.finalize_current_module_macro_resolutions();
2662 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2665 // Descend into the block.
2666 for stmt in &block.stmts {
2667 if let ast::StmtKind::Item(ref item) = stmt.node {
2668 if let ast::ItemKind::MacroDef(..) = item.node {
2669 num_macro_definition_ribs += 1;
2670 let def = self.definitions.local_def_id(item.id);
2671 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2672 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2676 self.visit_stmt(stmt);
2680 self.current_module = orig_module;
2681 for _ in 0 .. num_macro_definition_ribs {
2682 self.ribs[ValueNS].pop();
2683 self.label_ribs.pop();
2685 self.ribs[ValueNS].pop();
2686 if let Some(_) = anonymous_module {
2687 self.ribs[TypeNS].pop();
2689 debug!("(resolving block) leaving block");
2692 fn fresh_binding(&mut self,
2695 outer_pat_id: NodeId,
2696 pat_src: PatternSource,
2697 bindings: &mut FxHashMap<Ident, NodeId>)
2699 // Add the binding to the local ribs, if it
2700 // doesn't already exist in the bindings map. (We
2701 // must not add it if it's in the bindings map
2702 // because that breaks the assumptions later
2703 // passes make about or-patterns.)
2704 let ident = ident.modern_and_legacy();
2705 let mut def = Def::Local(pat_id);
2706 match bindings.get(&ident).cloned() {
2707 Some(id) if id == outer_pat_id => {
2708 // `Variant(a, a)`, error
2712 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2716 Some(..) if pat_src == PatternSource::FnParam => {
2717 // `fn f(a: u8, a: u8)`, error
2721 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2725 Some(..) if pat_src == PatternSource::Match ||
2726 pat_src == PatternSource::IfLet ||
2727 pat_src == PatternSource::WhileLet => {
2728 // `Variant1(a) | Variant2(a)`, ok
2729 // Reuse definition from the first `a`.
2730 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2733 span_bug!(ident.span, "two bindings with the same name from \
2734 unexpected pattern source {:?}", pat_src);
2737 // A completely fresh binding, add to the lists if it's valid.
2738 if ident.name != keywords::Invalid.name() {
2739 bindings.insert(ident, outer_pat_id);
2740 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2745 PathResolution::new(def)
2748 fn resolve_pattern(&mut self,
2750 pat_src: PatternSource,
2751 // Maps idents to the node ID for the
2752 // outermost pattern that binds them.
2753 bindings: &mut FxHashMap<Ident, NodeId>) {
2754 // Visit all direct subpatterns of this pattern.
2755 let outer_pat_id = pat.id;
2756 pat.walk(&mut |pat| {
2758 PatKind::Ident(bmode, ident, ref opt_pat) => {
2759 // First try to resolve the identifier as some existing
2760 // entity, then fall back to a fresh binding.
2761 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2763 .and_then(LexicalScopeBinding::item);
2764 let resolution = binding.map(NameBinding::def).and_then(|def| {
2765 let is_syntactic_ambiguity = opt_pat.is_none() &&
2766 bmode == BindingMode::ByValue(Mutability::Immutable);
2768 Def::StructCtor(_, CtorKind::Const) |
2769 Def::VariantCtor(_, CtorKind::Const) |
2770 Def::Const(..) if is_syntactic_ambiguity => {
2771 // Disambiguate in favor of a unit struct/variant
2772 // or constant pattern.
2773 self.record_use(ident, ValueNS, binding.unwrap(), ident.span);
2774 Some(PathResolution::new(def))
2776 Def::StructCtor(..) | Def::VariantCtor(..) |
2777 Def::Const(..) | Def::Static(..) => {
2778 // This is unambiguously a fresh binding, either syntactically
2779 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2780 // to something unusable as a pattern (e.g. constructor function),
2781 // but we still conservatively report an error, see
2782 // issues/33118#issuecomment-233962221 for one reason why.
2786 ResolutionError::BindingShadowsSomethingUnacceptable(
2787 pat_src.descr(), ident.name, binding.unwrap())
2791 Def::Fn(..) | Def::Err => {
2792 // These entities are explicitly allowed
2793 // to be shadowed by fresh bindings.
2797 span_bug!(ident.span, "unexpected definition for an \
2798 identifier in pattern: {:?}", def);
2801 }).unwrap_or_else(|| {
2802 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2805 self.record_def(pat.id, resolution);
2808 PatKind::TupleStruct(ref path, ..) => {
2809 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2812 PatKind::Path(ref qself, ref path) => {
2813 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2816 PatKind::Struct(ref path, ..) => {
2817 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2825 visit::walk_pat(self, pat);
2828 // High-level and context dependent path resolution routine.
2829 // Resolves the path and records the resolution into definition map.
2830 // If resolution fails tries several techniques to find likely
2831 // resolution candidates, suggest imports or other help, and report
2832 // errors in user friendly way.
2833 fn smart_resolve_path(&mut self,
2835 qself: Option<&QSelf>,
2839 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2842 /// A variant of `smart_resolve_path` where you also specify extra
2843 /// information about where the path came from; this extra info is
2844 /// sometimes needed for the lint that recommends rewriting
2845 /// absolute paths to `crate`, so that it knows how to frame the
2846 /// suggestion. If you are just resolving a path like `foo::bar`
2847 /// that appears...somewhere, though, then you just want
2848 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2849 /// already provides.
2850 fn smart_resolve_path_with_crate_lint(
2853 qself: Option<&QSelf>,
2856 crate_lint: CrateLint
2857 ) -> PathResolution {
2858 let segments = &path.segments.iter()
2859 .map(|seg| seg.ident)
2860 .collect::<Vec<_>>();
2861 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2864 fn smart_resolve_path_fragment(&mut self,
2866 qself: Option<&QSelf>,
2870 crate_lint: CrateLint)
2872 let ident_span = path.last().map_or(span, |ident| ident.span);
2873 let ns = source.namespace();
2874 let is_expected = &|def| source.is_expected(def);
2875 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2877 // Base error is amended with one short label and possibly some longer helps/notes.
2878 let report_errors = |this: &mut Self, def: Option<Def>| {
2879 // Make the base error.
2880 let expected = source.descr_expected();
2881 let path_str = names_to_string(path);
2882 let code = source.error_code(def.is_some());
2883 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2884 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2885 format!("not a {}", expected),
2888 let item_str = path[path.len() - 1];
2889 let item_span = path[path.len() - 1].span;
2890 let (mod_prefix, mod_str) = if path.len() == 1 {
2891 (format!(""), format!("this scope"))
2892 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2893 (format!(""), format!("the crate root"))
2895 let mod_path = &path[..path.len() - 1];
2896 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS),
2897 false, span, CrateLint::No) {
2898 PathResult::Module(module) => module.def(),
2900 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2901 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2903 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2904 format!("not found in {}", mod_str),
2907 let code = DiagnosticId::Error(code.into());
2908 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2910 // Emit special messages for unresolved `Self` and `self`.
2911 if is_self_type(path, ns) {
2912 __diagnostic_used!(E0411);
2913 err.code(DiagnosticId::Error("E0411".into()));
2914 err.span_label(span, "`Self` is only available in traits and impls");
2915 return (err, Vec::new());
2917 if is_self_value(path, ns) {
2918 __diagnostic_used!(E0424);
2919 err.code(DiagnosticId::Error("E0424".into()));
2920 err.span_label(span, format!("`self` value is only available in \
2921 methods with `self` parameter"));
2922 return (err, Vec::new());
2925 // Try to lookup the name in more relaxed fashion for better error reporting.
2926 let ident = *path.last().unwrap();
2927 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2928 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2929 let enum_candidates =
2930 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
2931 let mut enum_candidates = enum_candidates.iter()
2932 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2933 enum_candidates.sort();
2934 for (sp, variant_path, enum_path) in enum_candidates {
2936 let msg = format!("there is an enum variant `{}`, \
2942 err.span_suggestion(span, "you can try using the variant's enum",
2947 if path.len() == 1 && this.self_type_is_available(span) {
2948 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
2949 let self_is_available = this.self_value_is_available(path[0].span, span);
2951 AssocSuggestion::Field => {
2952 err.span_suggestion(span, "try",
2953 format!("self.{}", path_str));
2954 if !self_is_available {
2955 err.span_label(span, format!("`self` value is only available in \
2956 methods with `self` parameter"));
2959 AssocSuggestion::MethodWithSelf if self_is_available => {
2960 err.span_suggestion(span, "try",
2961 format!("self.{}", path_str));
2963 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2964 err.span_suggestion(span, "try",
2965 format!("Self::{}", path_str));
2968 return (err, candidates);
2972 let mut levenshtein_worked = false;
2975 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2976 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2977 levenshtein_worked = true;
2980 // Try context dependent help if relaxed lookup didn't work.
2981 if let Some(def) = def {
2982 match (def, source) {
2983 (Def::Macro(..), _) => {
2984 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2985 return (err, candidates);
2987 (Def::TyAlias(..), PathSource::Trait(_)) => {
2988 err.span_label(span, "type aliases cannot be used for traits");
2989 return (err, candidates);
2991 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2992 ExprKind::Field(_, ident) => {
2993 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2995 return (err, candidates);
2997 ExprKind::MethodCall(ref segment, ..) => {
2998 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2999 path_str, segment.ident));
3000 return (err, candidates);
3004 (Def::Enum(..), PathSource::TupleStruct)
3005 | (Def::Enum(..), PathSource::Expr(..)) => {
3006 if let Some(variants) = this.collect_enum_variants(def) {
3007 err.note(&format!("did you mean to use one \
3008 of the following variants?\n{}",
3010 .map(|suggestion| path_names_to_string(suggestion))
3011 .map(|suggestion| format!("- `{}`", suggestion))
3012 .collect::<Vec<_>>()
3016 err.note("did you mean to use one of the enum's variants?");
3018 return (err, candidates);
3020 (Def::Struct(def_id), _) if ns == ValueNS => {
3021 if let Some((ctor_def, ctor_vis))
3022 = this.struct_constructors.get(&def_id).cloned() {
3023 let accessible_ctor = this.is_accessible(ctor_vis);
3024 if is_expected(ctor_def) && !accessible_ctor {
3025 err.span_label(span, format!("constructor is not visible \
3026 here due to private fields"));
3029 // HACK(estebank): find a better way to figure out that this was a
3030 // parser issue where a struct literal is being used on an expression
3031 // where a brace being opened means a block is being started. Look
3032 // ahead for the next text to see if `span` is followed by a `{`.
3033 let cm = this.session.codemap();
3036 sp = cm.next_point(sp);
3037 match cm.span_to_snippet(sp) {
3038 Ok(ref snippet) => {
3039 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3046 let followed_by_brace = match cm.span_to_snippet(sp) {
3047 Ok(ref snippet) if snippet == "{" => true,
3050 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3053 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3058 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3062 return (err, candidates);
3064 (Def::Union(..), _) |
3065 (Def::Variant(..), _) |
3066 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3067 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3069 return (err, candidates);
3071 (Def::SelfTy(..), _) if ns == ValueNS => {
3072 err.span_label(span, fallback_label);
3073 err.note("can't use `Self` as a constructor, you must use the \
3074 implemented struct");
3075 return (err, candidates);
3077 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3078 err.note("can't use a type alias as a constructor");
3079 return (err, candidates);
3086 if !levenshtein_worked {
3087 err.span_label(base_span, fallback_label);
3088 this.type_ascription_suggestion(&mut err, base_span);
3092 let report_errors = |this: &mut Self, def: Option<Def>| {
3093 let (err, candidates) = report_errors(this, def);
3094 let def_id = this.current_module.normal_ancestor_id;
3095 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3096 let better = def.is_some();
3097 this.use_injections.push(UseError { err, candidates, node_id, better });
3098 err_path_resolution()
3101 let resolution = match self.resolve_qpath_anywhere(
3107 source.defer_to_typeck(),
3108 source.global_by_default(),
3111 Some(resolution) if resolution.unresolved_segments() == 0 => {
3112 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3115 // Add a temporary hack to smooth the transition to new struct ctor
3116 // visibility rules. See #38932 for more details.
3118 if let Def::Struct(def_id) = resolution.base_def() {
3119 if let Some((ctor_def, ctor_vis))
3120 = self.struct_constructors.get(&def_id).cloned() {
3121 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3122 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3123 self.session.buffer_lint(lint, id, span,
3124 "private struct constructors are not usable through \
3125 re-exports in outer modules",
3127 res = Some(PathResolution::new(ctor_def));
3132 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3135 Some(resolution) if source.defer_to_typeck() => {
3136 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3137 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3138 // it needs to be added to the trait map.
3140 let item_name = *path.last().unwrap();
3141 let traits = self.get_traits_containing_item(item_name, ns);
3142 self.trait_map.insert(id, traits);
3146 _ => report_errors(self, None)
3149 if let PathSource::TraitItem(..) = source {} else {
3150 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3151 self.record_def(id, resolution);
3156 fn type_ascription_suggestion(&self,
3157 err: &mut DiagnosticBuilder,
3159 debug!("type_ascription_suggetion {:?}", base_span);
3160 let cm = self.session.codemap();
3161 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3162 if let Some(sp) = self.current_type_ascription.last() {
3164 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3165 sp = cm.next_point(sp);
3166 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3167 debug!("snippet {:?}", snippet);
3168 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3169 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3170 debug!("{:?} {:?}", line_sp, line_base_sp);
3172 err.span_label(base_span,
3173 "expecting a type here because of type ascription");
3174 if line_sp != line_base_sp {
3175 err.span_suggestion_short(sp,
3176 "did you mean to use `;` here instead?",
3180 } else if snippet.trim().len() != 0 {
3181 debug!("tried to find type ascription `:` token, couldn't find it");
3191 fn self_type_is_available(&mut self, span: Span) -> bool {
3192 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3193 TypeNS, false, span);
3194 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3197 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3198 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3199 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, path_span);
3200 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3203 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3204 fn resolve_qpath_anywhere(&mut self,
3206 qself: Option<&QSelf>,
3208 primary_ns: Namespace,
3210 defer_to_typeck: bool,
3211 global_by_default: bool,
3212 crate_lint: CrateLint)
3213 -> Option<PathResolution> {
3214 let mut fin_res = None;
3215 // FIXME: can't resolve paths in macro namespace yet, macros are
3216 // processed by the little special hack below.
3217 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3218 if i == 0 || ns != primary_ns {
3219 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3220 // If defer_to_typeck, then resolution > no resolution,
3221 // otherwise full resolution > partial resolution > no resolution.
3222 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3224 res => if fin_res.is_none() { fin_res = res },
3228 let is_global = self.global_macros.get(&path[0].name).cloned()
3229 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3230 if primary_ns != MacroNS && (is_global ||
3231 self.macro_names.contains(&path[0].modern())) {
3232 // Return some dummy definition, it's enough for error reporting.
3234 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3240 /// Handles paths that may refer to associated items.
3241 fn resolve_qpath(&mut self,
3243 qself: Option<&QSelf>,
3247 global_by_default: bool,
3248 crate_lint: CrateLint)
3249 -> Option<PathResolution> {
3251 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3252 ns={:?}, span={:?}, global_by_default={:?})",
3261 if let Some(qself) = qself {
3262 if qself.position == 0 {
3263 // This is a case like `<T>::B`, where there is no
3264 // trait to resolve. In that case, we leave the `B`
3265 // segment to be resolved by type-check.
3266 return Some(PathResolution::with_unresolved_segments(
3267 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3271 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3273 // Currently, `path` names the full item (`A::B::C`, in
3274 // our example). so we extract the prefix of that that is
3275 // the trait (the slice upto and including
3276 // `qself.position`). And then we recursively resolve that,
3277 // but with `qself` set to `None`.
3279 // However, setting `qself` to none (but not changing the
3280 // span) loses the information about where this path
3281 // *actually* appears, so for the purposes of the crate
3282 // lint we pass along information that this is the trait
3283 // name from a fully qualified path, and this also
3284 // contains the full span (the `CrateLint::QPathTrait`).
3285 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3286 let res = self.smart_resolve_path_fragment(
3289 &path[..qself.position + 1],
3291 PathSource::TraitItem(ns),
3292 CrateLint::QPathTrait {
3294 qpath_span: qself.path_span,
3298 // The remaining segments (the `C` in our example) will
3299 // have to be resolved by type-check, since that requires doing
3300 // trait resolution.
3301 return Some(PathResolution::with_unresolved_segments(
3302 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3306 let result = match self.resolve_path(
3313 PathResult::NonModule(path_res) => path_res,
3314 PathResult::Module(module) if !module.is_normal() => {
3315 PathResolution::new(module.def().unwrap())
3317 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3318 // don't report an error right away, but try to fallback to a primitive type.
3319 // So, we are still able to successfully resolve something like
3321 // use std::u8; // bring module u8 in scope
3322 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3323 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3324 // // not to non-existent std::u8::max_value
3327 // Such behavior is required for backward compatibility.
3328 // The same fallback is used when `a` resolves to nothing.
3329 PathResult::Module(..) | PathResult::Failed(..)
3330 if (ns == TypeNS || path.len() > 1) &&
3331 self.primitive_type_table.primitive_types
3332 .contains_key(&path[0].name) => {
3333 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3334 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3336 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
3337 PathResult::Failed(span, msg, false) => {
3338 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3339 err_path_resolution()
3341 PathResult::Failed(..) => return None,
3342 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3345 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3346 path[0].name != keywords::CrateRoot.name() &&
3347 path[0].name != keywords::DollarCrate.name() {
3348 let unqualified_result = {
3349 match self.resolve_path(
3350 &[*path.last().unwrap()],
3356 PathResult::NonModule(path_res) => path_res.base_def(),
3357 PathResult::Module(module) => module.def().unwrap(),
3358 _ => return Some(result),
3361 if result.base_def() == unqualified_result {
3362 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3363 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3373 opt_ns: Option<Namespace>, // `None` indicates a module path
3376 crate_lint: CrateLint,
3377 ) -> PathResult<'a> {
3378 let mut module = None;
3379 let mut allow_super = true;
3380 let mut second_binding = None;
3383 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3384 path_span={:?}, crate_lint={:?})",
3392 for (i, &ident) in path.iter().enumerate() {
3393 debug!("resolve_path ident {} {:?}", i, ident);
3394 let is_last = i == path.len() - 1;
3395 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3396 let name = ident.name;
3398 if i == 0 && ns == TypeNS && name == keywords::SelfValue.name() {
3399 let mut ctxt = ident.span.ctxt().modern();
3400 module = Some(self.resolve_self(&mut ctxt, self.current_module));
3402 } else if allow_super && ns == TypeNS && name == keywords::Super.name() {
3403 let mut ctxt = ident.span.ctxt().modern();
3404 let self_module = match i {
3405 0 => self.resolve_self(&mut ctxt, self.current_module),
3406 _ => module.unwrap(),
3408 if let Some(parent) = self_module.parent {
3409 module = Some(self.resolve_self(&mut ctxt, parent));
3412 let msg = "There are too many initial `super`s.".to_string();
3413 return PathResult::Failed(ident.span, msg, false);
3415 } else if i == 0 && ns == TypeNS && name == keywords::Extern.name() {
3418 allow_super = false;
3421 if (i == 0 && name == keywords::CrateRoot.name()) ||
3422 (i == 0 && name == keywords::Crate.name()) ||
3423 (i == 0 && name == keywords::DollarCrate.name()) ||
3424 (i == 1 && name == keywords::Crate.name() &&
3425 path[0].name == keywords::CrateRoot.name()) {
3426 // `::a::b`, `crate::a::b`, `::crate::a::b` or `$crate::a::b`
3427 module = Some(self.resolve_crate_root(ident));
3429 } else if i == 1 && !ident.is_path_segment_keyword() {
3430 let prev_name = path[0].name;
3431 if prev_name == keywords::Extern.name() ||
3432 prev_name == keywords::CrateRoot.name() &&
3433 self.session.features_untracked().extern_absolute_paths &&
3434 self.session.rust_2018() {
3435 // `::extern_crate::a::b`
3436 let crate_id = self.crate_loader.process_path_extern(name, ident.span);
3438 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3439 self.populate_module_if_necessary(crate_root);
3440 module = Some(crate_root);
3446 // Report special messages for path segment keywords in wrong positions.
3447 if name == keywords::CrateRoot.name() && i != 0 ||
3448 name == keywords::DollarCrate.name() && i != 0 ||
3449 name == keywords::SelfValue.name() && i != 0 ||
3450 name == keywords::SelfType.name() && i != 0 ||
3451 name == keywords::Super.name() && i != 0 ||
3452 name == keywords::Extern.name() && i != 0 ||
3453 // we allow crate::foo and ::crate::foo but nothing else
3454 name == keywords::Crate.name() && i > 1 &&
3455 path[0].name != keywords::CrateRoot.name() ||
3456 name == keywords::Crate.name() && path.len() == 1 {
3457 let name_str = if name == keywords::CrateRoot.name() {
3458 format!("crate root")
3460 format!("`{}`", name)
3462 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3463 format!("global paths cannot start with {}", name_str)
3465 format!("{} in paths can only be used in start position", name_str)
3467 return PathResult::Failed(ident.span, msg, false);
3470 let binding = if let Some(module) = module {
3471 self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
3472 } else if opt_ns == Some(MacroNS) {
3473 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
3474 .map(MacroBinding::binding)
3476 match self.resolve_ident_in_lexical_scope(ident, ns, record_used, path_span) {
3477 // we found a locally-imported or available item/module
3478 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3479 // we found a local variable or type param
3480 Some(LexicalScopeBinding::Def(def))
3481 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3482 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3486 _ => Err(if record_used { Determined } else { Undetermined }),
3493 second_binding = Some(binding);
3495 let def = binding.def();
3496 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3497 if let Some(next_module) = binding.module() {
3498 module = Some(next_module);
3499 } else if def == Def::Err {
3500 return PathResult::NonModule(err_path_resolution());
3501 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3502 self.lint_if_path_starts_with_module(
3508 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3509 def, path.len() - i - 1
3512 return PathResult::Failed(ident.span,
3513 format!("Not a module `{}`", ident),
3517 Err(Undetermined) => return PathResult::Indeterminate,
3518 Err(Determined) => {
3519 if let Some(module) = module {
3520 if opt_ns.is_some() && !module.is_normal() {
3521 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3522 module.def().unwrap(), path.len() - i
3526 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
3527 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3528 let mut candidates =
3529 self.lookup_import_candidates(name, TypeNS, is_mod);
3530 candidates.sort_by_cached_key(|c| {
3531 (c.path.segments.len(), c.path.to_string())
3533 if let Some(candidate) = candidates.get(0) {
3534 format!("Did you mean `{}`?", candidate.path)
3536 format!("Maybe a missing `extern crate {};`?", ident)
3539 format!("Use of undeclared type or module `{}`", ident)
3541 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3543 return PathResult::Failed(ident.span, msg, is_last);
3548 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3550 PathResult::Module(module.unwrap_or(self.graph_root))
3553 fn lint_if_path_starts_with_module(
3555 crate_lint: CrateLint,
3558 second_binding: Option<&NameBinding>,
3560 let (diag_id, diag_span) = match crate_lint {
3561 CrateLint::No => return,
3562 CrateLint::SimplePath(id) => (id, path_span),
3563 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3564 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3567 let first_name = match path.get(0) {
3568 Some(ident) => ident.name,
3572 // We're only interested in `use` paths which should start with
3573 // `{{root}}` or `extern` currently.
3574 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3579 // If this import looks like `crate::...` it's already good
3580 Some(ident) if ident.name == keywords::Crate.name() => return,
3581 // Otherwise go below to see if it's an extern crate
3583 // If the path has length one (and it's `CrateRoot` most likely)
3584 // then we don't know whether we're gonna be importing a crate or an
3585 // item in our crate. Defer this lint to elsewhere
3589 // If the first element of our path was actually resolved to an
3590 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3591 // warning, this looks all good!
3592 if let Some(binding) = second_binding {
3593 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3594 // Careful: we still want to rewrite paths from
3595 // renamed extern crates.
3596 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3602 self.lint_path_starts_with_module(diag_id, diag_span);
3605 fn lint_path_starts_with_module(&self, id: NodeId, span: Span) {
3606 // In the 2018 edition this lint is a hard error, so nothing to do
3607 if self.session.rust_2018() {
3610 // In the 2015 edition there's no use in emitting lints unless the
3611 // crate's already enabled the feature that we're going to suggest
3612 if !self.session.features_untracked().crate_in_paths {
3615 let diag = lint::builtin::BuiltinLintDiagnostics
3616 ::AbsPathWithModule(span);
3617 self.session.buffer_lint_with_diagnostic(
3618 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3620 "absolute paths must start with `self`, `super`, \
3621 `crate`, or an external crate name in the 2018 edition",
3625 // Resolve a local definition, potentially adjusting for closures.
3626 fn adjust_local_def(&mut self,
3631 span: Span) -> Def {
3632 let ribs = &self.ribs[ns][rib_index + 1..];
3634 // An invalid forward use of a type parameter from a previous default.
3635 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3637 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3639 assert_eq!(def, Def::Err);
3645 span_bug!(span, "unexpected {:?} in bindings", def)
3647 Def::Local(node_id) => {
3650 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3651 ForwardTyParamBanRibKind => {
3652 // Nothing to do. Continue.
3654 ClosureRibKind(function_id) => {
3657 let seen = self.freevars_seen
3659 .or_insert_with(|| NodeMap());
3660 if let Some(&index) = seen.get(&node_id) {
3661 def = Def::Upvar(node_id, index, function_id);
3664 let vec = self.freevars
3666 .or_insert_with(|| vec![]);
3667 let depth = vec.len();
3668 def = Def::Upvar(node_id, depth, function_id);
3675 seen.insert(node_id, depth);
3678 ItemRibKind | TraitOrImplItemRibKind => {
3679 // This was an attempt to access an upvar inside a
3680 // named function item. This is not allowed, so we
3683 resolve_error(self, span,
3684 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3688 ConstantItemRibKind => {
3689 // Still doesn't deal with upvars
3691 resolve_error(self, span,
3692 ResolutionError::AttemptToUseNonConstantValueInConstant);
3699 Def::TyParam(..) | Def::SelfTy(..) => {
3702 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3703 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3704 ConstantItemRibKind => {
3705 // Nothing to do. Continue.
3708 // This was an attempt to use a type parameter outside
3711 resolve_error(self, span,
3712 ResolutionError::TypeParametersFromOuterFunction(def));
3724 fn lookup_assoc_candidate<FilterFn>(&mut self,
3727 filter_fn: FilterFn)
3728 -> Option<AssocSuggestion>
3729 where FilterFn: Fn(Def) -> bool
3731 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3733 TyKind::Path(None, _) => Some(t.id),
3734 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3735 // This doesn't handle the remaining `Ty` variants as they are not
3736 // that commonly the self_type, it might be interesting to provide
3737 // support for those in future.
3742 // Fields are generally expected in the same contexts as locals.
3743 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3744 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3745 // Look for a field with the same name in the current self_type.
3746 if let Some(resolution) = self.def_map.get(&node_id) {
3747 match resolution.base_def() {
3748 Def::Struct(did) | Def::Union(did)
3749 if resolution.unresolved_segments() == 0 => {
3750 if let Some(field_names) = self.field_names.get(&did) {
3751 if field_names.iter().any(|&field_name| ident.name == field_name) {
3752 return Some(AssocSuggestion::Field);
3762 // Look for associated items in the current trait.
3763 if let Some((module, _)) = self.current_trait_ref {
3764 if let Ok(binding) =
3765 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3766 let def = binding.def();
3768 return Some(if self.has_self.contains(&def.def_id()) {
3769 AssocSuggestion::MethodWithSelf
3771 AssocSuggestion::AssocItem
3780 fn lookup_typo_candidate<FilterFn>(&mut self,
3783 filter_fn: FilterFn,
3786 where FilterFn: Fn(Def) -> bool
3788 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3789 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3790 if let Some(binding) = resolution.borrow().binding {
3791 if filter_fn(binding.def()) {
3792 names.push(ident.name);
3798 let mut names = Vec::new();
3799 if path.len() == 1 {
3800 // Search in lexical scope.
3801 // Walk backwards up the ribs in scope and collect candidates.
3802 for rib in self.ribs[ns].iter().rev() {
3803 // Locals and type parameters
3804 for (ident, def) in &rib.bindings {
3805 if filter_fn(*def) {
3806 names.push(ident.name);
3810 if let ModuleRibKind(module) = rib.kind {
3811 // Items from this module
3812 add_module_candidates(module, &mut names);
3814 if let ModuleKind::Block(..) = module.kind {
3815 // We can see through blocks
3817 // Items from the prelude
3818 if !module.no_implicit_prelude {
3819 names.extend(self.extern_prelude.iter().cloned());
3820 if let Some(prelude) = self.prelude {
3821 add_module_candidates(prelude, &mut names);
3828 // Add primitive types to the mix
3829 if filter_fn(Def::PrimTy(TyBool)) {
3830 for (name, _) in &self.primitive_type_table.primitive_types {
3835 // Search in module.
3836 let mod_path = &path[..path.len() - 1];
3837 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3838 false, span, CrateLint::No) {
3839 add_module_candidates(module, &mut names);
3843 let name = path[path.len() - 1].name;
3844 // Make sure error reporting is deterministic.
3845 names.sort_by_cached_key(|name| name.as_str());
3846 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3847 Some(found) if found != name => Some(found),
3852 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3853 where F: FnOnce(&mut Resolver)
3855 if let Some(label) = label {
3856 self.unused_labels.insert(id, label.ident.span);
3857 let def = Def::Label(id);
3858 self.with_label_rib(|this| {
3859 let ident = label.ident.modern_and_legacy();
3860 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
3868 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3869 self.with_resolved_label(label, id, |this| this.visit_block(block));
3872 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3873 // First, record candidate traits for this expression if it could
3874 // result in the invocation of a method call.
3876 self.record_candidate_traits_for_expr_if_necessary(expr);
3878 // Next, resolve the node.
3880 ExprKind::Path(ref qself, ref path) => {
3881 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3882 visit::walk_expr(self, expr);
3885 ExprKind::Struct(ref path, ..) => {
3886 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3887 visit::walk_expr(self, expr);
3890 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3891 let def = self.search_label(label.ident, |rib, ident| {
3892 rib.bindings.get(&ident.modern_and_legacy()).cloned()
3896 // Search again for close matches...
3897 // Picks the first label that is "close enough", which is not necessarily
3898 // the closest match
3899 let close_match = self.search_label(label.ident, |rib, ident| {
3900 let names = rib.bindings.iter().map(|(id, _)| &id.name);
3901 find_best_match_for_name(names, &*ident.as_str(), None)
3903 self.record_def(expr.id, err_path_resolution());
3906 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
3909 Some(Def::Label(id)) => {
3910 // Since this def is a label, it is never read.
3911 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
3912 self.unused_labels.remove(&id);
3915 span_bug!(expr.span, "label wasn't mapped to a label def!");
3919 // visit `break` argument if any
3920 visit::walk_expr(self, expr);
3923 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
3924 self.visit_expr(subexpression);
3926 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3927 let mut bindings_list = FxHashMap();
3929 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
3931 // This has to happen *after* we determine which pat_idents are variants
3932 self.check_consistent_bindings(pats);
3933 self.visit_block(if_block);
3934 self.ribs[ValueNS].pop();
3936 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3939 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3941 ExprKind::While(ref subexpression, ref block, label) => {
3942 self.with_resolved_label(label, expr.id, |this| {
3943 this.visit_expr(subexpression);
3944 this.visit_block(block);
3948 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
3949 self.with_resolved_label(label, expr.id, |this| {
3950 this.visit_expr(subexpression);
3951 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3952 let mut bindings_list = FxHashMap();
3954 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
3956 // This has to happen *after* we determine which pat_idents are variants
3957 this.check_consistent_bindings(pats);
3958 this.visit_block(block);
3959 this.ribs[ValueNS].pop();
3963 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3964 self.visit_expr(subexpression);
3965 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3966 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3968 self.resolve_labeled_block(label, expr.id, block);
3970 self.ribs[ValueNS].pop();
3973 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
3975 // Equivalent to `visit::walk_expr` + passing some context to children.
3976 ExprKind::Field(ref subexpression, _) => {
3977 self.resolve_expr(subexpression, Some(expr));
3979 ExprKind::MethodCall(ref segment, ref arguments) => {
3980 let mut arguments = arguments.iter();
3981 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3982 for argument in arguments {
3983 self.resolve_expr(argument, None);
3985 self.visit_path_segment(expr.span, segment);
3988 ExprKind::Call(ref callee, ref arguments) => {
3989 self.resolve_expr(callee, Some(expr));
3990 for argument in arguments {
3991 self.resolve_expr(argument, None);
3994 ExprKind::Type(ref type_expr, _) => {
3995 self.current_type_ascription.push(type_expr.span);
3996 visit::walk_expr(self, expr);
3997 self.current_type_ascription.pop();
3999 // Resolve the body of async exprs inside the async closure to which they desugar
4000 ExprKind::Async(_, async_closure_id, ref block) => {
4001 let rib_kind = ClosureRibKind(async_closure_id);
4002 self.ribs[ValueNS].push(Rib::new(rib_kind));
4003 self.label_ribs.push(Rib::new(rib_kind));
4004 self.visit_block(&block);
4005 self.label_ribs.pop();
4006 self.ribs[ValueNS].pop();
4008 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4009 // resolve the arguments within the proper scopes so that usages of them inside the
4010 // closure are detected as upvars rather than normal closure arg usages.
4012 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4013 ref fn_decl, ref body, _span,
4015 let rib_kind = ClosureRibKind(expr.id);
4016 self.ribs[ValueNS].push(Rib::new(rib_kind));
4017 self.label_ribs.push(Rib::new(rib_kind));
4018 // Resolve arguments:
4019 let mut bindings_list = FxHashMap();
4020 for argument in &fn_decl.inputs {
4021 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4022 self.visit_ty(&argument.ty);
4024 // No need to resolve return type-- the outer closure return type is
4025 // FunctionRetTy::Default
4027 // Now resolve the inner closure
4029 let rib_kind = ClosureRibKind(inner_closure_id);
4030 self.ribs[ValueNS].push(Rib::new(rib_kind));
4031 self.label_ribs.push(Rib::new(rib_kind));
4032 // No need to resolve arguments: the inner closure has none.
4033 // Resolve the return type:
4034 visit::walk_fn_ret_ty(self, &fn_decl.output);
4036 self.visit_expr(body);
4037 self.label_ribs.pop();
4038 self.ribs[ValueNS].pop();
4040 self.label_ribs.pop();
4041 self.ribs[ValueNS].pop();
4044 visit::walk_expr(self, expr);
4049 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4051 ExprKind::Field(_, ident) => {
4052 // FIXME(#6890): Even though you can't treat a method like a
4053 // field, we need to add any trait methods we find that match
4054 // the field name so that we can do some nice error reporting
4055 // later on in typeck.
4056 let traits = self.get_traits_containing_item(ident, ValueNS);
4057 self.trait_map.insert(expr.id, traits);
4059 ExprKind::MethodCall(ref segment, ..) => {
4060 debug!("(recording candidate traits for expr) recording traits for {}",
4062 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4063 self.trait_map.insert(expr.id, traits);
4071 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4072 -> Vec<TraitCandidate> {
4073 debug!("(getting traits containing item) looking for '{}'", ident.name);
4075 let mut found_traits = Vec::new();
4076 // Look for the current trait.
4077 if let Some((module, _)) = self.current_trait_ref {
4078 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
4079 let def_id = module.def_id().unwrap();
4080 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4084 ident.span = ident.span.modern();
4085 let mut search_module = self.current_module;
4087 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4088 search_module = unwrap_or!(
4089 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4093 if let Some(prelude) = self.prelude {
4094 if !search_module.no_implicit_prelude {
4095 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4102 fn get_traits_in_module_containing_item(&mut self,
4106 found_traits: &mut Vec<TraitCandidate>) {
4107 let mut traits = module.traits.borrow_mut();
4108 if traits.is_none() {
4109 let mut collected_traits = Vec::new();
4110 module.for_each_child(|name, ns, binding| {
4111 if ns != TypeNS { return }
4112 if let Def::Trait(_) = binding.def() {
4113 collected_traits.push((name, binding));
4116 *traits = Some(collected_traits.into_boxed_slice());
4119 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4120 let module = binding.module().unwrap();
4121 let mut ident = ident;
4122 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4125 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
4127 let import_id = match binding.kind {
4128 NameBindingKind::Import { directive, .. } => {
4129 self.maybe_unused_trait_imports.insert(directive.id);
4130 self.add_to_glob_map(directive.id, trait_name);
4135 let trait_def_id = module.def_id().unwrap();
4136 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4141 /// When name resolution fails, this method can be used to look up candidate
4142 /// entities with the expected name. It allows filtering them using the
4143 /// supplied predicate (which should be used to only accept the types of
4144 /// definitions expected e.g. traits). The lookup spans across all crates.
4146 /// NOTE: The method does not look into imports, but this is not a problem,
4147 /// since we report the definitions (thus, the de-aliased imports).
4148 fn lookup_import_candidates<FilterFn>(&mut self,
4150 namespace: Namespace,
4151 filter_fn: FilterFn)
4152 -> Vec<ImportSuggestion>
4153 where FilterFn: Fn(Def) -> bool
4155 let mut candidates = Vec::new();
4156 let mut worklist = Vec::new();
4157 let mut seen_modules = FxHashSet();
4158 worklist.push((self.graph_root, Vec::new(), false));
4160 while let Some((in_module,
4162 in_module_is_extern)) = worklist.pop() {
4163 self.populate_module_if_necessary(in_module);
4165 // We have to visit module children in deterministic order to avoid
4166 // instabilities in reported imports (#43552).
4167 in_module.for_each_child_stable(|ident, ns, name_binding| {
4168 // avoid imports entirely
4169 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4170 // avoid non-importable candidates as well
4171 if !name_binding.is_importable() { return; }
4173 // collect results based on the filter function
4174 if ident.name == lookup_name && ns == namespace {
4175 if filter_fn(name_binding.def()) {
4177 let mut segms = if self.session.rust_2018() && !in_module_is_extern {
4178 // crate-local absolute paths start with `crate::` in edition 2018
4179 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4180 let mut full_segms = vec![
4181 ast::PathSegment::from_ident(keywords::Crate.ident())
4183 full_segms.extend(path_segments.clone());
4186 path_segments.clone()
4189 segms.push(ast::PathSegment::from_ident(ident));
4191 span: name_binding.span,
4194 // the entity is accessible in the following cases:
4195 // 1. if it's defined in the same crate, it's always
4196 // accessible (since private entities can be made public)
4197 // 2. if it's defined in another crate, it's accessible
4198 // only if both the module is public and the entity is
4199 // declared as public (due to pruning, we don't explore
4200 // outside crate private modules => no need to check this)
4201 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4202 candidates.push(ImportSuggestion { path: path });
4207 // collect submodules to explore
4208 if let Some(module) = name_binding.module() {
4210 let mut path_segments = path_segments.clone();
4211 path_segments.push(ast::PathSegment::from_ident(ident));
4213 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4214 // add the module to the lookup
4215 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4216 if seen_modules.insert(module.def_id().unwrap()) {
4217 worklist.push((module, path_segments, is_extern));
4227 fn find_module(&mut self,
4229 -> Option<(Module<'a>, ImportSuggestion)>
4231 let mut result = None;
4232 let mut worklist = Vec::new();
4233 let mut seen_modules = FxHashSet();
4234 worklist.push((self.graph_root, Vec::new()));
4236 while let Some((in_module, path_segments)) = worklist.pop() {
4237 // abort if the module is already found
4238 if let Some(_) = result { break; }
4240 self.populate_module_if_necessary(in_module);
4242 in_module.for_each_child_stable(|ident, _, name_binding| {
4243 // abort if the module is already found or if name_binding is private external
4244 if result.is_some() || !name_binding.vis.is_visible_locally() {
4247 if let Some(module) = name_binding.module() {
4249 let mut path_segments = path_segments.clone();
4250 path_segments.push(ast::PathSegment::from_ident(ident));
4251 if module.def() == Some(module_def) {
4253 span: name_binding.span,
4254 segments: path_segments,
4256 result = Some((module, ImportSuggestion { path: path }));
4258 // add the module to the lookup
4259 if seen_modules.insert(module.def_id().unwrap()) {
4260 worklist.push((module, path_segments));
4270 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4271 if let Def::Enum(..) = enum_def {} else {
4272 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4275 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4276 self.populate_module_if_necessary(enum_module);
4278 let mut variants = Vec::new();
4279 enum_module.for_each_child_stable(|ident, _, name_binding| {
4280 if let Def::Variant(..) = name_binding.def() {
4281 let mut segms = enum_import_suggestion.path.segments.clone();
4282 segms.push(ast::PathSegment::from_ident(ident));
4283 variants.push(Path {
4284 span: name_binding.span,
4293 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4294 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4295 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4296 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4300 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4302 ast::VisibilityKind::Public => ty::Visibility::Public,
4303 ast::VisibilityKind::Crate(..) => {
4304 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4306 ast::VisibilityKind::Inherited => {
4307 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4309 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4310 // Visibilities are resolved as global by default, add starting root segment.
4311 let segments = path.make_root().iter().chain(path.segments.iter())
4312 .map(|seg| seg.ident)
4313 .collect::<Vec<_>>();
4314 let def = self.smart_resolve_path_fragment(
4319 PathSource::Visibility,
4320 CrateLint::SimplePath(id),
4322 if def == Def::Err {
4323 ty::Visibility::Public
4325 let vis = ty::Visibility::Restricted(def.def_id());
4326 if self.is_accessible(vis) {
4329 self.session.span_err(path.span, "visibilities can only be restricted \
4330 to ancestor modules");
4331 ty::Visibility::Public
4338 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4339 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4342 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4343 vis.is_accessible_from(module.normal_ancestor_id, self)
4346 fn report_errors(&mut self, krate: &Crate) {
4347 self.report_shadowing_errors();
4348 self.report_with_use_injections(krate);
4349 self.report_proc_macro_import(krate);
4350 let mut reported_spans = FxHashSet();
4352 for &AmbiguityError { span, name, b1, b2, lexical } in &self.ambiguity_errors {
4353 if !reported_spans.insert(span) { continue }
4354 let participle = |binding: &NameBinding| {
4355 if binding.is_import() { "imported" } else { "defined" }
4357 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
4358 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
4359 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
4360 format!("consider adding an explicit import of `{}` to disambiguate", name)
4361 } else if let Def::Macro(..) = b1.def() {
4362 format!("macro-expanded {} do not shadow",
4363 if b1.is_import() { "macro imports" } else { "macros" })
4365 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4366 if b1.is_import() { "imports" } else { "items" })
4369 let mut err = struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
4370 err.span_note(b1.span, &msg1);
4372 Def::Macro(..) if b2.span.is_dummy() =>
4373 err.note(&format!("`{}` is also a builtin macro", name)),
4374 _ => err.span_note(b2.span, &msg2),
4376 err.note(¬e).emit();
4379 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4380 if !reported_spans.insert(span) { continue }
4381 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4385 fn report_with_use_injections(&mut self, krate: &Crate) {
4386 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4387 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4388 if !candidates.is_empty() {
4389 show_candidates(&mut err, span, &candidates, better, found_use);
4395 fn report_shadowing_errors(&mut self) {
4396 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
4397 self.resolve_legacy_scope(scope, ident, true);
4400 let mut reported_errors = FxHashSet();
4401 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4402 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4403 reported_errors.insert((binding.ident, binding.span)) {
4404 let msg = format!("`{}` is already in scope", binding.ident);
4405 self.session.struct_span_err(binding.span, &msg)
4406 .note("macro-expanded `macro_rules!`s may not shadow \
4407 existing macros (see RFC 1560)")
4413 fn report_conflict<'b>(&mut self,
4417 new_binding: &NameBinding<'b>,
4418 old_binding: &NameBinding<'b>) {
4419 // Error on the second of two conflicting names
4420 if old_binding.span.lo() > new_binding.span.lo() {
4421 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4424 let container = match parent.kind {
4425 ModuleKind::Def(Def::Mod(_), _) => "module",
4426 ModuleKind::Def(Def::Trait(_), _) => "trait",
4427 ModuleKind::Block(..) => "block",
4431 let old_noun = match old_binding.is_import() {
4433 false => "definition",
4436 let new_participle = match new_binding.is_import() {
4441 let (name, span) = (ident.name, self.session.codemap().def_span(new_binding.span));
4443 if let Some(s) = self.name_already_seen.get(&name) {
4449 let old_kind = match (ns, old_binding.module()) {
4450 (ValueNS, _) => "value",
4451 (MacroNS, _) => "macro",
4452 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4453 (TypeNS, Some(module)) if module.is_normal() => "module",
4454 (TypeNS, Some(module)) if module.is_trait() => "trait",
4455 (TypeNS, _) => "type",
4458 let msg = format!("the name `{}` is defined multiple times", name);
4460 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4461 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4462 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4463 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4464 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4466 _ => match (old_binding.is_import(), new_binding.is_import()) {
4467 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4468 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4469 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4473 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4478 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4479 if !old_binding.span.is_dummy() {
4480 err.span_label(self.session.codemap().def_span(old_binding.span),
4481 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4484 // See https://github.com/rust-lang/rust/issues/32354
4485 if old_binding.is_import() || new_binding.is_import() {
4486 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4492 let cm = self.session.codemap();
4493 let rename_msg = "You can use `as` to change the binding name of the import";
4495 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4496 binding.is_renamed_extern_crate()) {
4497 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4498 format!("Other{}", name)
4500 format!("other_{}", name)
4503 err.span_suggestion(binding.span,
4505 if snippet.ends_with(';') {
4506 format!("{} as {};",
4507 &snippet[..snippet.len()-1],
4510 format!("{} as {}", snippet, suggested_name)
4513 err.span_label(binding.span, rename_msg);
4518 self.name_already_seen.insert(name, span);
4521 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
4522 if self.use_extern_macros { return; }
4525 if attr.path.segments.len() > 1 {
4528 let ident = attr.path.segments[0].ident;
4529 let result = self.resolve_lexical_macro_path_segment(ident,
4533 if let Ok(binding) = result {
4534 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
4535 attr::mark_known(attr);
4537 let msg = "attribute procedural macros are experimental";
4538 let feature = "proc_macro";
4540 feature_err(&self.session.parse_sess, feature,
4541 attr.span, GateIssue::Language, msg)
4542 .span_label(binding.span(), "procedural macro imported here")
4550 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4551 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4554 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4555 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4558 fn names_to_string(idents: &[Ident]) -> String {
4559 let mut result = String::new();
4560 for (i, ident) in idents.iter()
4561 .filter(|ident| ident.name != keywords::CrateRoot.name())
4564 result.push_str("::");
4566 result.push_str(&ident.as_str());
4571 fn path_names_to_string(path: &Path) -> String {
4572 names_to_string(&path.segments.iter()
4573 .map(|seg| seg.ident)
4574 .collect::<Vec<_>>())
4577 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4578 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4579 let variant_path = &suggestion.path;
4580 let variant_path_string = path_names_to_string(variant_path);
4582 let path_len = suggestion.path.segments.len();
4583 let enum_path = ast::Path {
4584 span: suggestion.path.span,
4585 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4587 let enum_path_string = path_names_to_string(&enum_path);
4589 (suggestion.path.span, variant_path_string, enum_path_string)
4593 /// When an entity with a given name is not available in scope, we search for
4594 /// entities with that name in all crates. This method allows outputting the
4595 /// results of this search in a programmer-friendly way
4596 fn show_candidates(err: &mut DiagnosticBuilder,
4597 // This is `None` if all placement locations are inside expansions
4599 candidates: &[ImportSuggestion],
4603 // we want consistent results across executions, but candidates are produced
4604 // by iterating through a hash map, so make sure they are ordered:
4605 let mut path_strings: Vec<_> =
4606 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4607 path_strings.sort();
4609 let better = if better { "better " } else { "" };
4610 let msg_diff = match path_strings.len() {
4611 1 => " is found in another module, you can import it",
4612 _ => "s are found in other modules, you can import them",
4614 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4616 if let Some(span) = span {
4617 for candidate in &mut path_strings {
4618 // produce an additional newline to separate the new use statement
4619 // from the directly following item.
4620 let additional_newline = if found_use {
4625 *candidate = format!("use {};\n{}", candidate, additional_newline);
4628 err.span_suggestions(span, &msg, path_strings);
4632 for candidate in path_strings {
4634 msg.push_str(&candidate);
4639 /// A somewhat inefficient routine to obtain the name of a module.
4640 fn module_to_string(module: Module) -> Option<String> {
4641 let mut names = Vec::new();
4643 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4644 if let ModuleKind::Def(_, name) = module.kind {
4645 if let Some(parent) = module.parent {
4646 names.push(Ident::with_empty_ctxt(name));
4647 collect_mod(names, parent);
4650 // danger, shouldn't be ident?
4651 names.push(Ident::from_str("<opaque>"));
4652 collect_mod(names, module.parent.unwrap());
4655 collect_mod(&mut names, module);
4657 if names.is_empty() {
4660 Some(names_to_string(&names.into_iter()
4662 .collect::<Vec<_>>()))
4665 fn err_path_resolution() -> PathResolution {
4666 PathResolution::new(Def::Err)
4669 #[derive(PartialEq,Copy, Clone)]
4670 pub enum MakeGlobMap {
4675 #[derive(Copy, Clone, Debug)]
4677 /// Do not issue the lint
4680 /// This lint applies to some random path like `impl ::foo::Bar`
4681 /// or whatever. In this case, we can take the span of that path.
4684 /// This lint comes from a `use` statement. In this case, what we
4685 /// care about really is the *root* `use` statement; e.g., if we
4686 /// have nested things like `use a::{b, c}`, we care about the
4688 UsePath { root_id: NodeId, root_span: Span },
4690 /// This is the "trait item" from a fully qualified path. For example,
4691 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4692 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4693 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4696 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }