1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
16 #![feature(rustc_diagnostic_macros)]
22 extern crate syntax_pos;
23 extern crate rustc_errors as errors;
27 extern crate rustc_data_structures;
29 use self::Namespace::*;
30 use self::TypeParameters::*;
33 use rustc::hir::map::{Definitions, DefCollector};
34 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
35 use rustc::middle::cstore::{CrateStore, CrateLoader};
36 use rustc::session::Session;
38 use rustc::hir::def::*;
39 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
41 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
42 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
44 use syntax::codemap::{dummy_spanned, respan, BytePos, CodeMap};
45 use syntax::ext::hygiene::{Mark, MarkKind, SyntaxContext};
46 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
47 use syntax::ext::base::SyntaxExtension;
48 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
49 use syntax::ext::base::MacroKind;
50 use syntax::symbol::{Symbol, keywords};
51 use syntax::util::lev_distance::find_best_match_for_name;
53 use syntax::visit::{self, FnKind, Visitor};
55 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
56 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParam, Generics};
57 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
58 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
59 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
60 use syntax::feature_gate::{feature_err, GateIssue};
61 use syntax::parse::token;
64 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
65 use errors::{DiagnosticBuilder, DiagnosticId};
67 use std::cell::{Cell, RefCell};
69 use std::collections::BTreeSet;
72 use std::mem::replace;
73 use rustc_data_structures::sync::Lrc;
75 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
76 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
78 // NB: This module needs to be declared first so diagnostics are
79 // registered before they are used.
84 mod build_reduced_graph;
87 /// A free importable items suggested in case of resolution failure.
88 struct ImportSuggestion {
92 /// A field or associated item from self type suggested in case of resolution failure.
93 enum AssocSuggestion {
100 struct BindingError {
102 origin: BTreeSet<Span>,
103 target: BTreeSet<Span>,
106 impl PartialOrd for BindingError {
107 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
108 Some(self.cmp(other))
112 impl PartialEq for BindingError {
113 fn eq(&self, other: &BindingError) -> bool {
114 self.name == other.name
118 impl Ord for BindingError {
119 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
120 self.name.cmp(&other.name)
124 enum ResolutionError<'a> {
125 /// error E0401: can't use type parameters from outer function
126 TypeParametersFromOuterFunction(Def),
127 /// error E0403: the name is already used for a type parameter in this type parameter list
128 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
129 /// error E0407: method is not a member of trait
130 MethodNotMemberOfTrait(Name, &'a str),
131 /// error E0437: type is not a member of trait
132 TypeNotMemberOfTrait(Name, &'a str),
133 /// error E0438: const is not a member of trait
134 ConstNotMemberOfTrait(Name, &'a str),
135 /// error E0408: variable `{}` is not bound in all patterns
136 VariableNotBoundInPattern(&'a BindingError),
137 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
138 VariableBoundWithDifferentMode(Name, Span),
139 /// error E0415: identifier is bound more than once in this parameter list
140 IdentifierBoundMoreThanOnceInParameterList(&'a str),
141 /// error E0416: identifier is bound more than once in the same pattern
142 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
143 /// error E0426: use of undeclared label
144 UndeclaredLabel(&'a str, Option<Name>),
145 /// error E0429: `self` imports are only allowed within a { } list
146 SelfImportsOnlyAllowedWithin,
147 /// error E0430: `self` import can only appear once in the list
148 SelfImportCanOnlyAppearOnceInTheList,
149 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
150 SelfImportOnlyInImportListWithNonEmptyPrefix,
151 /// error E0432: unresolved import
152 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
153 /// error E0433: failed to resolve
154 FailedToResolve(&'a str),
155 /// error E0434: can't capture dynamic environment in a fn item
156 CannotCaptureDynamicEnvironmentInFnItem,
157 /// error E0435: attempt to use a non-constant value in a constant
158 AttemptToUseNonConstantValueInConstant,
159 /// error E0530: X bindings cannot shadow Ys
160 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
161 /// error E0128: type parameters with a default cannot use forward declared identifiers
162 ForwardDeclaredTyParam,
165 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
167 resolution_error: ResolutionError<'a>) {
168 resolve_struct_error(resolver, span, resolution_error).emit();
171 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
173 resolution_error: ResolutionError<'a>)
174 -> DiagnosticBuilder<'sess> {
175 match resolution_error {
176 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
177 let mut err = struct_span_err!(resolver.session,
180 "can't use type parameters from outer function");
181 err.span_label(span, "use of type variable from outer function");
183 let cm = resolver.session.codemap();
185 Def::SelfTy(_, maybe_impl_defid) => {
186 if let Some(impl_span) = maybe_impl_defid.map_or(None,
187 |def_id| resolver.definitions.opt_span(def_id)) {
188 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
189 "`Self` type implicitely declared here, on the `impl`");
192 Def::TyParam(typaram_defid) => {
193 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
194 err.span_label(typaram_span, "type variable from outer function");
197 Def::Mod(..) | Def::Struct(..) | Def::Union(..) | Def::Enum(..) | Def::Variant(..) |
198 Def::Trait(..) | Def::TyAlias(..) | Def::TyForeign(..) | Def::TraitAlias(..) |
199 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::Fn(..) | Def::Const(..) |
200 Def::Static(..) | Def::StructCtor(..) | Def::VariantCtor(..) | Def::Method(..) |
201 Def::AssociatedConst(..) | Def::Local(..) | Def::Upvar(..) | Def::Label(..) |
202 Def::Macro(..) | Def::GlobalAsm(..) | Def::Err =>
203 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
207 // Try to retrieve the span of the function signature and generate a new message with
208 // a local type parameter
209 let sugg_msg = "try using a local type parameter instead";
210 if let Some((sugg_span, new_snippet)) = generate_local_type_param_snippet(cm, span) {
211 // Suggest the modification to the user
212 err.span_suggestion(sugg_span,
215 } else if let Some(sp) = generate_fn_name_span(cm, span) {
216 err.span_label(sp, "try adding a local type parameter in this method instead");
218 err.help("try using a local type parameter instead");
223 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
224 let mut err = struct_span_err!(resolver.session,
227 "the name `{}` is already used for a type parameter \
228 in this type parameter list",
230 err.span_label(span, "already used");
231 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
234 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
235 let mut err = struct_span_err!(resolver.session,
238 "method `{}` is not a member of trait `{}`",
241 err.span_label(span, format!("not a member of trait `{}`", trait_));
244 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
245 let mut err = struct_span_err!(resolver.session,
248 "type `{}` is not a member of trait `{}`",
251 err.span_label(span, format!("not a member of trait `{}`", trait_));
254 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
255 let mut err = struct_span_err!(resolver.session,
258 "const `{}` is not a member of trait `{}`",
261 err.span_label(span, format!("not a member of trait `{}`", trait_));
264 ResolutionError::VariableNotBoundInPattern(binding_error) => {
265 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
266 let msp = MultiSpan::from_spans(target_sp.clone());
267 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
268 let mut err = resolver.session.struct_span_err_with_code(
271 DiagnosticId::Error("E0408".into()),
273 for sp in target_sp {
274 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
276 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
277 for sp in origin_sp {
278 err.span_label(sp, "variable not in all patterns");
282 ResolutionError::VariableBoundWithDifferentMode(variable_name,
283 first_binding_span) => {
284 let mut err = struct_span_err!(resolver.session,
287 "variable `{}` is bound in inconsistent \
288 ways within the same match arm",
290 err.span_label(span, "bound in different ways");
291 err.span_label(first_binding_span, "first binding");
294 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
295 let mut err = struct_span_err!(resolver.session,
298 "identifier `{}` is bound more than once in this parameter list",
300 err.span_label(span, "used as parameter more than once");
303 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
304 let mut err = struct_span_err!(resolver.session,
307 "identifier `{}` is bound more than once in the same pattern",
309 err.span_label(span, "used in a pattern more than once");
312 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
313 let mut err = struct_span_err!(resolver.session,
316 "use of undeclared label `{}`",
318 if let Some(lev_candidate) = lev_candidate {
319 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
321 err.span_label(span, format!("undeclared label `{}`", name));
325 ResolutionError::SelfImportsOnlyAllowedWithin => {
326 struct_span_err!(resolver.session,
330 "`self` imports are only allowed within a { } list")
332 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
333 let mut err = struct_span_err!(resolver.session, span, E0430,
334 "`self` import can only appear once in an import list");
335 err.span_label(span, "can only appear once in an import list");
338 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
339 let mut err = struct_span_err!(resolver.session, span, E0431,
340 "`self` import can only appear in an import list with \
341 a non-empty prefix");
342 err.span_label(span, "can only appear in an import list with a non-empty prefix");
345 ResolutionError::UnresolvedImport(name) => {
346 let (span, msg) = match name {
347 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
348 None => (span, "unresolved import".to_owned()),
350 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
351 if let Some((_, _, p)) = name {
352 err.span_label(span, p);
356 ResolutionError::FailedToResolve(msg) => {
357 let mut err = struct_span_err!(resolver.session, span, E0433,
358 "failed to resolve. {}", msg);
359 err.span_label(span, msg);
362 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
363 let mut err = struct_span_err!(resolver.session,
367 "can't capture dynamic environment in a fn item");
368 err.help("use the `|| { ... }` closure form instead");
371 ResolutionError::AttemptToUseNonConstantValueInConstant => {
372 let mut err = struct_span_err!(resolver.session, span, E0435,
373 "attempt to use a non-constant value in a constant");
374 err.span_label(span, "non-constant value");
377 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
378 let shadows_what = PathResolution::new(binding.def()).kind_name();
379 let mut err = struct_span_err!(resolver.session,
382 "{}s cannot shadow {}s", what_binding, shadows_what);
383 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
384 let participle = if binding.is_import() { "imported" } else { "defined" };
385 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
386 err.span_label(binding.span, msg);
389 ResolutionError::ForwardDeclaredTyParam => {
390 let mut err = struct_span_err!(resolver.session, span, E0128,
391 "type parameters with a default cannot use \
392 forward declared identifiers");
393 err.span_label(span, format!("defaulted type parameters cannot be forward declared"));
399 /// Adjust the impl span so that just the `impl` keyword is taken by removing
400 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
401 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
403 /// Attention: The method used is very fragile since it essentially duplicates the work of the
404 /// parser. If you need to use this function or something similar, please consider updating the
405 /// codemap functions and this function to something more robust.
406 fn reduce_impl_span_to_impl_keyword(cm: &CodeMap, impl_span: Span) -> Span {
407 let impl_span = cm.span_until_char(impl_span, '<');
408 let impl_span = cm.span_until_whitespace(impl_span);
412 fn generate_fn_name_span(cm: &CodeMap, span: Span) -> Option<Span> {
413 let prev_span = cm.span_extend_to_prev_str(span, "fn", true);
414 cm.span_to_snippet(prev_span).map(|snippet| {
415 let len = snippet.find(|c: char| !c.is_alphanumeric() && c != '_')
416 .expect("no label after fn");
417 prev_span.with_hi(BytePos(prev_span.lo().0 + len as u32))
421 /// Take the span of a type parameter in a function signature and try to generate a span for the
422 /// function name (with generics) and a new snippet for this span with the pointed type parameter as
423 /// a new local type parameter.
428 /// fn my_function(param: T)
432 /// fn my_function(param: T)
433 /// ^^^^^^^^^^^ Generated span with snippet `my_function<T>`
436 /// Attention: The method used is very fragile since it essentially duplicates the work of the
437 /// parser. If you need to use this function or something similar, please consider updating the
438 /// codemap functions and this function to something more robust.
439 fn generate_local_type_param_snippet(cm: &CodeMap, span: Span) -> Option<(Span, String)> {
440 // Try to extend the span to the previous "fn" keyword to retrieve the function
442 let sugg_span = cm.span_extend_to_prev_str(span, "fn", false);
443 if sugg_span != span {
444 if let Ok(snippet) = cm.span_to_snippet(sugg_span) {
445 // Consume the function name
446 let mut offset = snippet.find(|c: char| !c.is_alphanumeric() && c != '_')
447 .expect("no label after fn");
449 // Consume the generics part of the function signature
450 let mut bracket_counter = 0;
451 let mut last_char = None;
452 for c in snippet[offset..].chars() {
454 '<' => bracket_counter += 1,
455 '>' => bracket_counter -= 1,
456 '(' => if bracket_counter == 0 { break; }
459 offset += c.len_utf8();
463 // Adjust the suggestion span to encompass the function name with its generics
464 let sugg_span = sugg_span.with_hi(BytePos(sugg_span.lo().0 + offset as u32));
466 // Prepare the new suggested snippet to append the type parameter that triggered
467 // the error in the generics of the function signature
468 let mut new_snippet = if last_char == Some('>') {
469 format!("{}, ", &snippet[..(offset - '>'.len_utf8())])
471 format!("{}<", &snippet[..offset])
473 new_snippet.push_str(&cm.span_to_snippet(span).unwrap_or("T".to_string()));
474 new_snippet.push('>');
476 return Some((sugg_span, new_snippet));
483 #[derive(Copy, Clone, Debug)]
486 binding_mode: BindingMode,
489 // Map from the name in a pattern to its binding mode.
490 type BindingMap = FxHashMap<Ident, BindingInfo>;
492 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
503 fn descr(self) -> &'static str {
505 PatternSource::Match => "match binding",
506 PatternSource::IfLet => "if let binding",
507 PatternSource::WhileLet => "while let binding",
508 PatternSource::Let => "let binding",
509 PatternSource::For => "for binding",
510 PatternSource::FnParam => "function parameter",
515 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
516 enum AliasPossibility {
521 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
522 enum PathSource<'a> {
523 // Type paths `Path`.
525 // Trait paths in bounds or impls.
526 Trait(AliasPossibility),
527 // Expression paths `path`, with optional parent context.
528 Expr(Option<&'a Expr>),
529 // Paths in path patterns `Path`.
531 // Paths in struct expressions and patterns `Path { .. }`.
533 // Paths in tuple struct patterns `Path(..)`.
535 // `m::A::B` in `<T as m::A>::B::C`.
536 TraitItem(Namespace),
537 // Path in `pub(path)`
539 // Path in `use a::b::{...};`
543 impl<'a> PathSource<'a> {
544 fn namespace(self) -> Namespace {
546 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
547 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
548 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
549 PathSource::TraitItem(ns) => ns,
553 fn global_by_default(self) -> bool {
555 PathSource::Visibility | PathSource::ImportPrefix => true,
556 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
557 PathSource::Struct | PathSource::TupleStruct |
558 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
562 fn defer_to_typeck(self) -> bool {
564 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
565 PathSource::Struct | PathSource::TupleStruct => true,
566 PathSource::Trait(_) | PathSource::TraitItem(..) |
567 PathSource::Visibility | PathSource::ImportPrefix => false,
571 fn descr_expected(self) -> &'static str {
573 PathSource::Type => "type",
574 PathSource::Trait(_) => "trait",
575 PathSource::Pat => "unit struct/variant or constant",
576 PathSource::Struct => "struct, variant or union type",
577 PathSource::TupleStruct => "tuple struct/variant",
578 PathSource::Visibility => "module",
579 PathSource::ImportPrefix => "module or enum",
580 PathSource::TraitItem(ns) => match ns {
581 TypeNS => "associated type",
582 ValueNS => "method or associated constant",
583 MacroNS => bug!("associated macro"),
585 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
586 // "function" here means "anything callable" rather than `Def::Fn`,
587 // this is not precise but usually more helpful than just "value".
588 Some(&ExprKind::Call(..)) => "function",
594 fn is_expected(self, def: Def) -> bool {
596 PathSource::Type => match def {
597 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
598 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
599 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
600 Def::TyForeign(..) => true,
603 PathSource::Trait(AliasPossibility::No) => match def {
604 Def::Trait(..) => true,
607 PathSource::Trait(AliasPossibility::Maybe) => match def {
608 Def::Trait(..) => true,
609 Def::TraitAlias(..) => true,
612 PathSource::Expr(..) => match def {
613 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
614 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
615 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
616 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
619 PathSource::Pat => match def {
620 Def::StructCtor(_, CtorKind::Const) |
621 Def::VariantCtor(_, CtorKind::Const) |
622 Def::Const(..) | Def::AssociatedConst(..) => true,
625 PathSource::TupleStruct => match def {
626 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
629 PathSource::Struct => match def {
630 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
631 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
634 PathSource::TraitItem(ns) => match def {
635 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
636 Def::AssociatedTy(..) if ns == TypeNS => true,
639 PathSource::ImportPrefix => match def {
640 Def::Mod(..) | Def::Enum(..) => true,
643 PathSource::Visibility => match def {
644 Def::Mod(..) => true,
650 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
651 __diagnostic_used!(E0404);
652 __diagnostic_used!(E0405);
653 __diagnostic_used!(E0412);
654 __diagnostic_used!(E0422);
655 __diagnostic_used!(E0423);
656 __diagnostic_used!(E0425);
657 __diagnostic_used!(E0531);
658 __diagnostic_used!(E0532);
659 __diagnostic_used!(E0573);
660 __diagnostic_used!(E0574);
661 __diagnostic_used!(E0575);
662 __diagnostic_used!(E0576);
663 __diagnostic_used!(E0577);
664 __diagnostic_used!(E0578);
665 match (self, has_unexpected_resolution) {
666 (PathSource::Trait(_), true) => "E0404",
667 (PathSource::Trait(_), false) => "E0405",
668 (PathSource::Type, true) => "E0573",
669 (PathSource::Type, false) => "E0412",
670 (PathSource::Struct, true) => "E0574",
671 (PathSource::Struct, false) => "E0422",
672 (PathSource::Expr(..), true) => "E0423",
673 (PathSource::Expr(..), false) => "E0425",
674 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
675 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
676 (PathSource::TraitItem(..), true) => "E0575",
677 (PathSource::TraitItem(..), false) => "E0576",
678 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
679 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
684 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
691 #[derive(Clone, Default, Debug)]
692 pub struct PerNS<T> {
698 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
700 fn index(&self, ns: Namespace) -> &T {
702 ValueNS => &self.value_ns,
703 TypeNS => &self.type_ns,
704 MacroNS => self.macro_ns.as_ref().unwrap(),
709 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
710 fn index_mut(&mut self, ns: Namespace) -> &mut T {
712 ValueNS => &mut self.value_ns,
713 TypeNS => &mut self.type_ns,
714 MacroNS => self.macro_ns.as_mut().unwrap(),
719 struct UsePlacementFinder {
720 target_module: NodeId,
725 impl UsePlacementFinder {
726 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
727 let mut finder = UsePlacementFinder {
732 visit::walk_crate(&mut finder, krate);
733 (finder.span, finder.found_use)
737 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
740 module: &'tcx ast::Mod,
742 _: &[ast::Attribute],
745 if self.span.is_some() {
748 if node_id != self.target_module {
749 visit::walk_mod(self, module);
752 // find a use statement
753 for item in &module.items {
755 ItemKind::Use(..) => {
756 // don't suggest placing a use before the prelude
757 // import or other generated ones
758 if item.span.ctxt().outer().expn_info().is_none() {
759 self.span = Some(item.span.shrink_to_lo());
760 self.found_use = true;
764 // don't place use before extern crate
765 ItemKind::ExternCrate(_) => {}
766 // but place them before the first other item
767 _ => if self.span.map_or(true, |span| item.span < span ) {
768 if item.span.ctxt().outer().expn_info().is_none() {
769 // don't insert between attributes and an item
770 if item.attrs.is_empty() {
771 self.span = Some(item.span.shrink_to_lo());
773 // find the first attribute on the item
774 for attr in &item.attrs {
775 if self.span.map_or(true, |span| attr.span < span) {
776 self.span = Some(attr.span.shrink_to_lo());
787 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
788 fn visit_item(&mut self, item: &'tcx Item) {
789 self.resolve_item(item);
791 fn visit_arm(&mut self, arm: &'tcx Arm) {
792 self.resolve_arm(arm);
794 fn visit_block(&mut self, block: &'tcx Block) {
795 self.resolve_block(block);
797 fn visit_expr(&mut self, expr: &'tcx Expr) {
798 self.resolve_expr(expr, None);
800 fn visit_local(&mut self, local: &'tcx Local) {
801 self.resolve_local(local);
803 fn visit_ty(&mut self, ty: &'tcx Ty) {
805 TyKind::Path(ref qself, ref path) => {
806 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
808 TyKind::ImplicitSelf => {
809 let self_ty = keywords::SelfType.ident();
810 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
811 .map_or(Def::Err, |d| d.def());
812 self.record_def(ty.id, PathResolution::new(def));
814 TyKind::Array(ref element, ref length) => {
815 self.visit_ty(element);
816 self.with_constant_rib(|this| {
817 this.visit_expr(length);
823 visit::walk_ty(self, ty);
825 fn visit_poly_trait_ref(&mut self,
826 tref: &'tcx ast::PolyTraitRef,
827 m: &'tcx ast::TraitBoundModifier) {
828 self.smart_resolve_path(tref.trait_ref.ref_id, None,
829 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
830 visit::walk_poly_trait_ref(self, tref, m);
832 fn visit_variant(&mut self,
833 variant: &'tcx ast::Variant,
834 generics: &'tcx Generics,
835 item_id: ast::NodeId) {
836 if let Some(ref dis_expr) = variant.node.disr_expr {
837 // resolve the discriminator expr as a constant
838 self.with_constant_rib(|this| {
839 this.visit_expr(dis_expr);
843 // `visit::walk_variant` without the discriminant expression.
844 self.visit_variant_data(&variant.node.data,
850 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
851 let type_parameters = match foreign_item.node {
852 ForeignItemKind::Fn(_, ref generics) => {
853 HasTypeParameters(generics, ItemRibKind)
855 ForeignItemKind::Static(..) => NoTypeParameters,
856 ForeignItemKind::Ty => NoTypeParameters,
858 self.with_type_parameter_rib(type_parameters, |this| {
859 visit::walk_foreign_item(this, foreign_item);
862 fn visit_fn(&mut self,
863 function_kind: FnKind<'tcx>,
864 declaration: &'tcx FnDecl,
867 let rib_kind = match function_kind {
868 FnKind::ItemFn(..) => {
871 FnKind::Method(_, _, _, _) => {
872 TraitOrImplItemRibKind
874 FnKind::Closure(_) => ClosureRibKind(node_id),
877 // Create a value rib for the function.
878 self.ribs[ValueNS].push(Rib::new(rib_kind));
880 // Create a label rib for the function.
881 self.label_ribs.push(Rib::new(rib_kind));
883 // Add each argument to the rib.
884 let mut bindings_list = FxHashMap();
885 for argument in &declaration.inputs {
886 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
888 self.visit_ty(&argument.ty);
890 debug!("(resolving function) recorded argument");
892 visit::walk_fn_ret_ty(self, &declaration.output);
894 // Resolve the function body.
895 match function_kind {
896 FnKind::ItemFn(.., body) |
897 FnKind::Method(.., body) => {
898 self.visit_block(body);
900 FnKind::Closure(body) => {
901 self.visit_expr(body);
905 debug!("(resolving function) leaving function");
907 self.label_ribs.pop();
908 self.ribs[ValueNS].pop();
910 fn visit_generics(&mut self, generics: &'tcx Generics) {
911 // For type parameter defaults, we have to ban access
912 // to following type parameters, as the Substs can only
913 // provide previous type parameters as they're built.
914 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
915 default_ban_rib.bindings.extend(generics.params.iter()
916 .filter_map(|p| if let GenericParam::Type(ref tp) = *p { Some(tp) } else { None })
917 .skip_while(|p| p.default.is_none())
918 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
920 for param in &generics.params {
922 GenericParam::Lifetime(_) => self.visit_generic_param(param),
923 GenericParam::Type(ref ty_param) => {
924 for bound in &ty_param.bounds {
925 self.visit_ty_param_bound(bound);
928 if let Some(ref ty) = ty_param.default {
929 self.ribs[TypeNS].push(default_ban_rib);
931 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
934 // Allow all following defaults to refer to this type parameter.
935 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(ty_param.ident.name));
939 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
943 #[derive(Copy, Clone)]
944 enum TypeParameters<'a, 'b> {
946 HasTypeParameters(// Type parameters.
949 // The kind of the rib used for type parameters.
953 // The rib kind controls the translation of local
954 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
955 #[derive(Copy, Clone, Debug)]
957 // No translation needs to be applied.
960 // We passed through a closure scope at the given node ID.
961 // Translate upvars as appropriate.
962 ClosureRibKind(NodeId /* func id */),
964 // We passed through an impl or trait and are now in one of its
965 // methods or associated types. Allow references to ty params that impl or trait
966 // binds. Disallow any other upvars (including other ty params that are
968 TraitOrImplItemRibKind,
970 // We passed through an item scope. Disallow upvars.
973 // We're in a constant item. Can't refer to dynamic stuff.
976 // We passed through a module.
977 ModuleRibKind(Module<'a>),
979 // We passed through a `macro_rules!` statement
980 MacroDefinition(DefId),
982 // All bindings in this rib are type parameters that can't be used
983 // from the default of a type parameter because they're not declared
984 // before said type parameter. Also see the `visit_generics` override.
985 ForwardTyParamBanRibKind,
991 bindings: FxHashMap<Ident, Def>,
996 fn new(kind: RibKind<'a>) -> Rib<'a> {
998 bindings: FxHashMap(),
1004 enum LexicalScopeBinding<'a> {
1005 Item(&'a NameBinding<'a>),
1009 impl<'a> LexicalScopeBinding<'a> {
1010 fn item(self) -> Option<&'a NameBinding<'a>> {
1012 LexicalScopeBinding::Item(binding) => Some(binding),
1017 fn def(self) -> Def {
1019 LexicalScopeBinding::Item(binding) => binding.def(),
1020 LexicalScopeBinding::Def(def) => def,
1025 #[derive(Clone, Debug)]
1026 enum PathResult<'a> {
1028 NonModule(PathResolution),
1030 Failed(Span, String, bool /* is the error from the last segment? */),
1038 /// One node in the tree of modules.
1039 pub struct ModuleData<'a> {
1040 parent: Option<Module<'a>>,
1043 // The def id of the closest normal module (`mod`) ancestor (including this module).
1044 normal_ancestor_id: DefId,
1046 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1047 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
1048 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1050 // Macro invocations that can expand into items in this module.
1051 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1053 no_implicit_prelude: bool,
1055 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1056 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1058 // Used to memoize the traits in this module for faster searches through all traits in scope.
1059 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1061 // Whether this module is populated. If not populated, any attempt to
1062 // access the children must be preceded with a
1063 // `populate_module_if_necessary` call.
1064 populated: Cell<bool>,
1066 /// Span of the module itself. Used for error reporting.
1072 type Module<'a> = &'a ModuleData<'a>;
1074 impl<'a> ModuleData<'a> {
1075 fn new(parent: Option<Module<'a>>,
1077 normal_ancestor_id: DefId,
1079 span: Span) -> Self {
1084 resolutions: RefCell::new(FxHashMap()),
1085 legacy_macro_resolutions: RefCell::new(Vec::new()),
1086 macro_resolutions: RefCell::new(Vec::new()),
1087 unresolved_invocations: RefCell::new(FxHashSet()),
1088 no_implicit_prelude: false,
1089 glob_importers: RefCell::new(Vec::new()),
1090 globs: RefCell::new(Vec::new()),
1091 traits: RefCell::new(None),
1092 populated: Cell::new(normal_ancestor_id.is_local()),
1098 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1099 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1100 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1104 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1105 let resolutions = self.resolutions.borrow();
1106 let mut resolutions = resolutions.iter().map(|(&(ident, ns), &resolution)| {
1107 // Pre-compute keys for sorting
1108 (ident.name.as_str(), ns, ident, resolution)
1110 .collect::<Vec<_>>();
1111 resolutions.sort_unstable_by_key(|&(str, ns, ..)| (str, ns));
1112 for &(_, ns, ident, resolution) in resolutions.iter() {
1113 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1117 fn def(&self) -> Option<Def> {
1119 ModuleKind::Def(def, _) => Some(def),
1124 fn def_id(&self) -> Option<DefId> {
1125 self.def().as_ref().map(Def::def_id)
1128 // `self` resolves to the first module ancestor that `is_normal`.
1129 fn is_normal(&self) -> bool {
1131 ModuleKind::Def(Def::Mod(_), _) => true,
1136 fn is_trait(&self) -> bool {
1138 ModuleKind::Def(Def::Trait(_), _) => true,
1143 fn is_local(&self) -> bool {
1144 self.normal_ancestor_id.is_local()
1147 fn nearest_item_scope(&'a self) -> Module<'a> {
1148 if self.is_trait() { self.parent.unwrap() } else { self }
1152 impl<'a> fmt::Debug for ModuleData<'a> {
1153 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1154 write!(f, "{:?}", self.def())
1158 // Records a possibly-private value, type, or module definition.
1159 #[derive(Clone, Debug)]
1160 pub struct NameBinding<'a> {
1161 kind: NameBindingKind<'a>,
1164 vis: ty::Visibility,
1167 pub trait ToNameBinding<'a> {
1168 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1171 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1172 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1177 #[derive(Clone, Debug)]
1178 enum NameBindingKind<'a> {
1182 binding: &'a NameBinding<'a>,
1183 directive: &'a ImportDirective<'a>,
1185 legacy_self_import: bool,
1188 b1: &'a NameBinding<'a>,
1189 b2: &'a NameBinding<'a>,
1194 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1196 struct UseError<'a> {
1197 err: DiagnosticBuilder<'a>,
1198 /// Attach `use` statements for these candidates
1199 candidates: Vec<ImportSuggestion>,
1200 /// The node id of the module to place the use statements in
1202 /// Whether the diagnostic should state that it's "better"
1206 struct AmbiguityError<'a> {
1210 b1: &'a NameBinding<'a>,
1211 b2: &'a NameBinding<'a>,
1215 impl<'a> NameBinding<'a> {
1216 fn module(&self) -> Option<Module<'a>> {
1218 NameBindingKind::Module(module) => Some(module),
1219 NameBindingKind::Import { binding, .. } => binding.module(),
1220 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1225 fn def(&self) -> Def {
1227 NameBindingKind::Def(def) => def,
1228 NameBindingKind::Module(module) => module.def().unwrap(),
1229 NameBindingKind::Import { binding, .. } => binding.def(),
1230 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1231 NameBindingKind::Ambiguity { .. } => Def::Err,
1235 fn def_ignoring_ambiguity(&self) -> Def {
1237 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1238 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1243 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Lrc<SyntaxExtension> {
1244 resolver.get_macro(self.def_ignoring_ambiguity())
1247 // We sometimes need to treat variants as `pub` for backwards compatibility
1248 fn pseudo_vis(&self) -> ty::Visibility {
1249 if self.is_variant() && self.def().def_id().is_local() {
1250 ty::Visibility::Public
1256 fn is_variant(&self) -> bool {
1258 NameBindingKind::Def(Def::Variant(..)) |
1259 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1264 fn is_extern_crate(&self) -> bool {
1266 NameBindingKind::Import {
1267 directive: &ImportDirective {
1268 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1275 fn is_import(&self) -> bool {
1277 NameBindingKind::Import { .. } => true,
1282 fn is_renamed_extern_crate(&self) -> bool {
1283 if let NameBindingKind::Import { directive, ..} = self.kind {
1284 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1291 fn is_glob_import(&self) -> bool {
1293 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1294 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1299 fn is_importable(&self) -> bool {
1301 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1306 fn is_macro_def(&self) -> bool {
1308 NameBindingKind::Def(Def::Macro(..)) => true,
1313 fn descr(&self) -> &'static str {
1314 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1318 /// Interns the names of the primitive types.
1319 struct PrimitiveTypeTable {
1320 primitive_types: FxHashMap<Name, PrimTy>,
1323 impl PrimitiveTypeTable {
1324 fn new() -> PrimitiveTypeTable {
1325 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1327 table.intern("bool", TyBool);
1328 table.intern("char", TyChar);
1329 table.intern("f32", TyFloat(FloatTy::F32));
1330 table.intern("f64", TyFloat(FloatTy::F64));
1331 table.intern("isize", TyInt(IntTy::Isize));
1332 table.intern("i8", TyInt(IntTy::I8));
1333 table.intern("i16", TyInt(IntTy::I16));
1334 table.intern("i32", TyInt(IntTy::I32));
1335 table.intern("i64", TyInt(IntTy::I64));
1336 table.intern("i128", TyInt(IntTy::I128));
1337 table.intern("str", TyStr);
1338 table.intern("usize", TyUint(UintTy::Usize));
1339 table.intern("u8", TyUint(UintTy::U8));
1340 table.intern("u16", TyUint(UintTy::U16));
1341 table.intern("u32", TyUint(UintTy::U32));
1342 table.intern("u64", TyUint(UintTy::U64));
1343 table.intern("u128", TyUint(UintTy::U128));
1347 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1348 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1352 /// The main resolver class.
1353 pub struct Resolver<'a> {
1354 session: &'a Session,
1355 cstore: &'a CrateStore,
1357 pub definitions: Definitions,
1359 graph_root: Module<'a>,
1361 prelude: Option<Module<'a>>,
1363 // n.b. This is used only for better diagnostics, not name resolution itself.
1364 has_self: FxHashSet<DefId>,
1366 // Names of fields of an item `DefId` accessible with dot syntax.
1367 // Used for hints during error reporting.
1368 field_names: FxHashMap<DefId, Vec<Name>>,
1370 // All imports known to succeed or fail.
1371 determined_imports: Vec<&'a ImportDirective<'a>>,
1373 // All non-determined imports.
1374 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1376 // The module that represents the current item scope.
1377 current_module: Module<'a>,
1379 // The current set of local scopes for types and values.
1380 // FIXME #4948: Reuse ribs to avoid allocation.
1381 ribs: PerNS<Vec<Rib<'a>>>,
1383 // The current set of local scopes, for labels.
1384 label_ribs: Vec<Rib<'a>>,
1386 // The trait that the current context can refer to.
1387 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1389 // The current self type if inside an impl (used for better errors).
1390 current_self_type: Option<Ty>,
1392 // The idents for the primitive types.
1393 primitive_type_table: PrimitiveTypeTable,
1396 pub freevars: FreevarMap,
1397 freevars_seen: NodeMap<NodeMap<usize>>,
1398 pub export_map: ExportMap,
1399 pub trait_map: TraitMap,
1401 // A map from nodes to anonymous modules.
1402 // Anonymous modules are pseudo-modules that are implicitly created around items
1403 // contained within blocks.
1405 // For example, if we have this:
1413 // There will be an anonymous module created around `g` with the ID of the
1414 // entry block for `f`.
1415 block_map: NodeMap<Module<'a>>,
1416 module_map: FxHashMap<DefId, Module<'a>>,
1417 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1419 pub make_glob_map: bool,
1420 /// Maps imports to the names of items actually imported (this actually maps
1421 /// all imports, but only glob imports are actually interesting).
1422 pub glob_map: GlobMap,
1424 used_imports: FxHashSet<(NodeId, Namespace)>,
1425 pub maybe_unused_trait_imports: NodeSet,
1426 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1428 /// privacy errors are delayed until the end in order to deduplicate them
1429 privacy_errors: Vec<PrivacyError<'a>>,
1430 /// ambiguity errors are delayed for deduplication
1431 ambiguity_errors: Vec<AmbiguityError<'a>>,
1432 /// `use` injections are delayed for better placement and deduplication
1433 use_injections: Vec<UseError<'a>>,
1434 /// `use` injections for proc macros wrongly imported with #[macro_use]
1435 proc_mac_errors: Vec<macros::ProcMacError>,
1437 gated_errors: FxHashSet<Span>,
1438 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1440 arenas: &'a ResolverArenas<'a>,
1441 dummy_binding: &'a NameBinding<'a>,
1442 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1444 crate_loader: &'a mut CrateLoader,
1445 macro_names: FxHashSet<Ident>,
1446 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1447 pub all_macros: FxHashMap<Name, Def>,
1448 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1449 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1450 macro_defs: FxHashMap<Mark, DefId>,
1451 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1452 macro_exports: Vec<Export>,
1453 pub whitelisted_legacy_custom_derives: Vec<Name>,
1454 pub found_unresolved_macro: bool,
1456 // List of crate local macros that we need to warn about as being unused.
1457 // Right now this only includes macro_rules! macros, and macros 2.0.
1458 unused_macros: FxHashSet<DefId>,
1460 // Maps the `Mark` of an expansion to its containing module or block.
1461 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1463 // Avoid duplicated errors for "name already defined".
1464 name_already_seen: FxHashMap<Name, Span>,
1466 // If `#![feature(proc_macro)]` is set
1467 proc_macro_enabled: bool,
1469 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1470 warned_proc_macros: FxHashSet<Name>,
1472 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1474 // This table maps struct IDs into struct constructor IDs,
1475 // it's not used during normal resolution, only for better error reporting.
1476 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1478 // Only used for better errors on `fn(): fn()`
1479 current_type_ascription: Vec<Span>,
1481 injected_crate: Option<Module<'a>>,
1484 pub struct ResolverArenas<'a> {
1485 modules: arena::TypedArena<ModuleData<'a>>,
1486 local_modules: RefCell<Vec<Module<'a>>>,
1487 name_bindings: arena::TypedArena<NameBinding<'a>>,
1488 import_directives: arena::TypedArena<ImportDirective<'a>>,
1489 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1490 invocation_data: arena::TypedArena<InvocationData<'a>>,
1491 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1494 impl<'a> ResolverArenas<'a> {
1495 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1496 let module = self.modules.alloc(module);
1497 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1498 self.local_modules.borrow_mut().push(module);
1502 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1503 self.local_modules.borrow()
1505 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1506 self.name_bindings.alloc(name_binding)
1508 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1509 -> &'a ImportDirective {
1510 self.import_directives.alloc(import_directive)
1512 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1513 self.name_resolutions.alloc(Default::default())
1515 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1516 -> &'a InvocationData<'a> {
1517 self.invocation_data.alloc(expansion_data)
1519 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1520 self.legacy_bindings.alloc(binding)
1524 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1525 fn parent(self, id: DefId) -> Option<DefId> {
1527 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1528 _ => self.cstore.def_key(id).parent,
1529 }.map(|index| DefId { index: index, ..id })
1533 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1534 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1535 self.resolve_hir_path_cb(path, is_value,
1536 |resolver, span, error| resolve_error(resolver, span, error))
1539 fn resolve_str_path(&mut self, span: Span, crate_root: Option<&str>,
1540 components: &[&str], is_value: bool) -> hir::Path {
1541 let mut path = hir::Path {
1544 segments: iter::once(keywords::CrateRoot.name()).chain({
1545 crate_root.into_iter().chain(components.iter().cloned()).map(Symbol::intern)
1546 }).map(hir::PathSegment::from_name).collect(),
1549 self.resolve_hir_path(&mut path, is_value);
1553 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1554 self.def_map.get(&id).cloned()
1557 fn definitions(&mut self) -> &mut Definitions {
1558 &mut self.definitions
1562 impl<'a> Resolver<'a> {
1563 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1564 /// isn't something that can be returned because it can't be made to live that long,
1565 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1566 /// just that an error occurred.
1567 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1568 -> Result<hir::Path, ()> {
1570 let mut errored = false;
1572 let mut path = if path_str.starts_with("::") {
1576 segments: iter::once(keywords::CrateRoot.name()).chain({
1577 path_str.split("::").skip(1).map(Symbol::intern)
1578 }).map(hir::PathSegment::from_name).collect(),
1584 segments: path_str.split("::").map(Symbol::intern)
1585 .map(hir::PathSegment::from_name).collect(),
1588 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1589 if errored || path.def == Def::Err {
1596 /// resolve_hir_path, but takes a callback in case there was an error
1597 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1598 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1600 let namespace = if is_value { ValueNS } else { TypeNS };
1601 let hir::Path { ref segments, span, ref mut def } = *path;
1602 let path: Vec<SpannedIdent> = segments.iter()
1603 .map(|seg| respan(span, Ident::with_empty_ctxt(seg.name)))
1605 match self.resolve_path(&path, Some(namespace), true, span) {
1606 PathResult::Module(module) => *def = module.def().unwrap(),
1607 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1608 *def = path_res.base_def(),
1609 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1610 PathResult::Failed(span, msg, _) => {
1611 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1615 PathResult::Indeterminate => unreachable!(),
1616 PathResult::Failed(span, msg, _) => {
1617 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1623 impl<'a> Resolver<'a> {
1624 pub fn new(session: &'a Session,
1625 cstore: &'a CrateStore,
1628 make_glob_map: MakeGlobMap,
1629 crate_loader: &'a mut CrateLoader,
1630 arenas: &'a ResolverArenas<'a>)
1632 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1633 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1634 let graph_root = arenas.alloc_module(ModuleData {
1635 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1636 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1638 let mut module_map = FxHashMap();
1639 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1641 let mut definitions = Definitions::new();
1642 DefCollector::new(&mut definitions, Mark::root())
1643 .collect_root(crate_name, session.local_crate_disambiguator());
1645 let mut invocations = FxHashMap();
1646 invocations.insert(Mark::root(),
1647 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1649 let features = session.features_untracked();
1651 let mut macro_defs = FxHashMap();
1652 macro_defs.insert(Mark::root(), root_def_id);
1661 // The outermost module has def ID 0; this is not reflected in the
1666 has_self: FxHashSet(),
1667 field_names: FxHashMap(),
1669 determined_imports: Vec::new(),
1670 indeterminate_imports: Vec::new(),
1672 current_module: graph_root,
1674 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1675 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1676 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1678 label_ribs: Vec::new(),
1680 current_trait_ref: None,
1681 current_self_type: None,
1683 primitive_type_table: PrimitiveTypeTable::new(),
1686 freevars: NodeMap(),
1687 freevars_seen: NodeMap(),
1688 export_map: FxHashMap(),
1689 trait_map: NodeMap(),
1691 block_map: NodeMap(),
1692 extern_module_map: FxHashMap(),
1694 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1695 glob_map: NodeMap(),
1697 used_imports: FxHashSet(),
1698 maybe_unused_trait_imports: NodeSet(),
1699 maybe_unused_extern_crates: Vec::new(),
1701 privacy_errors: Vec::new(),
1702 ambiguity_errors: Vec::new(),
1703 use_injections: Vec::new(),
1704 proc_mac_errors: Vec::new(),
1705 gated_errors: FxHashSet(),
1706 disallowed_shadowing: Vec::new(),
1709 dummy_binding: arenas.alloc_name_binding(NameBinding {
1710 kind: NameBindingKind::Def(Def::Err),
1711 expansion: Mark::root(),
1713 vis: ty::Visibility::Public,
1716 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1718 features.use_extern_macros || features.proc_macro || features.decl_macro,
1721 macro_names: FxHashSet(),
1722 global_macros: FxHashMap(),
1723 all_macros: FxHashMap(),
1724 lexical_macro_resolutions: Vec::new(),
1725 macro_map: FxHashMap(),
1726 macro_exports: Vec::new(),
1729 local_macro_def_scopes: FxHashMap(),
1730 name_already_seen: FxHashMap(),
1731 whitelisted_legacy_custom_derives: Vec::new(),
1732 proc_macro_enabled: features.proc_macro,
1733 warned_proc_macros: FxHashSet(),
1734 potentially_unused_imports: Vec::new(),
1735 struct_constructors: DefIdMap(),
1736 found_unresolved_macro: false,
1737 unused_macros: FxHashSet(),
1738 current_type_ascription: Vec::new(),
1739 injected_crate: None,
1743 pub fn arenas() -> ResolverArenas<'a> {
1745 modules: arena::TypedArena::new(),
1746 local_modules: RefCell::new(Vec::new()),
1747 name_bindings: arena::TypedArena::new(),
1748 import_directives: arena::TypedArena::new(),
1749 name_resolutions: arena::TypedArena::new(),
1750 invocation_data: arena::TypedArena::new(),
1751 legacy_bindings: arena::TypedArena::new(),
1755 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1757 type_ns: f(self, TypeNS),
1758 value_ns: f(self, ValueNS),
1759 macro_ns: match self.use_extern_macros {
1760 true => Some(f(self, MacroNS)),
1766 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1768 match self.macro_defs.get(&ctxt.outer()) {
1769 Some(&def_id) => return def_id,
1770 None => ctxt.remove_mark(),
1775 /// Entry point to crate resolution.
1776 pub fn resolve_crate(&mut self, krate: &Crate) {
1777 ImportResolver { resolver: self }.finalize_imports();
1778 self.current_module = self.graph_root;
1779 self.finalize_current_module_macro_resolutions();
1781 visit::walk_crate(self, krate);
1783 check_unused::check_crate(self, krate);
1784 self.report_errors(krate);
1785 self.crate_loader.postprocess(krate);
1792 normal_ancestor_id: DefId,
1796 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1797 self.arenas.alloc_module(module)
1800 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1801 -> bool /* true if an error was reported */ {
1802 match binding.kind {
1803 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1806 directive.used.set(true);
1807 if legacy_self_import {
1808 self.warn_legacy_self_import(directive);
1811 self.used_imports.insert((directive.id, ns));
1812 self.add_to_glob_map(directive.id, ident);
1813 self.record_use(ident, ns, binding, span)
1815 NameBindingKind::Import { .. } => false,
1816 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1817 self.ambiguity_errors.push(AmbiguityError {
1818 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy,
1821 self.record_use(ident, ns, b1, span);
1829 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1830 if self.make_glob_map {
1831 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1835 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1836 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1837 /// `ident` in the first scope that defines it (or None if no scopes define it).
1839 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1840 /// the items are defined in the block. For example,
1843 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1846 /// g(); // This resolves to the local variable `g` since it shadows the item.
1850 /// Invariant: This must only be called during main resolution, not during
1851 /// import resolution.
1852 fn resolve_ident_in_lexical_scope(&mut self,
1857 -> Option<LexicalScopeBinding<'a>> {
1859 ident.ctxt = if ident.name == keywords::SelfType.name() {
1860 SyntaxContext::empty() // FIXME(jseyfried) improve `Self` hygiene
1866 // Walk backwards up the ribs in scope.
1867 let mut module = self.graph_root;
1868 for i in (0 .. self.ribs[ns].len()).rev() {
1869 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1870 // The ident resolves to a type parameter or local variable.
1871 return Some(LexicalScopeBinding::Def(
1872 self.adjust_local_def(ns, i, def, record_used, path_span)
1876 module = match self.ribs[ns][i].kind {
1877 ModuleRibKind(module) => module,
1878 MacroDefinition(def) if def == self.macro_def(ident.ctxt) => {
1879 // If an invocation of this macro created `ident`, give up on `ident`
1880 // and switch to `ident`'s source from the macro definition.
1881 ident.ctxt.remove_mark();
1887 let item = self.resolve_ident_in_module_unadjusted(
1888 module, ident, ns, false, record_used, path_span,
1890 if let Ok(binding) = item {
1891 // The ident resolves to an item.
1892 return Some(LexicalScopeBinding::Item(binding));
1896 ModuleKind::Block(..) => {}, // We can see through blocks
1901 ident.ctxt = ident.ctxt.modern();
1903 module = unwrap_or!(self.hygienic_lexical_parent(module, &mut ident.ctxt), break);
1904 let orig_current_module = self.current_module;
1905 self.current_module = module; // Lexical resolutions can never be a privacy error.
1906 let result = self.resolve_ident_in_module_unadjusted(
1907 module, ident, ns, false, record_used, path_span,
1909 self.current_module = orig_current_module;
1912 Ok(binding) => return Some(LexicalScopeBinding::Item(binding)),
1913 Err(Undetermined) => return None,
1914 Err(Determined) => {}
1918 match self.prelude {
1919 Some(prelude) if !module.no_implicit_prelude => {
1920 self.resolve_ident_in_module_unadjusted(prelude, ident, ns, false, false, path_span)
1921 .ok().map(LexicalScopeBinding::Item)
1927 fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, ctxt: &mut SyntaxContext)
1928 -> Option<Module<'a>> {
1929 if !module.expansion.is_descendant_of(ctxt.outer()) {
1930 return Some(self.macro_def_scope(ctxt.remove_mark()));
1933 if let ModuleKind::Block(..) = module.kind {
1934 return Some(module.parent.unwrap());
1937 let mut module_expansion = module.expansion.modern(); // for backward compatibility
1938 while let Some(parent) = module.parent {
1939 let parent_expansion = parent.expansion.modern();
1940 if module_expansion.is_descendant_of(parent_expansion) &&
1941 parent_expansion != module_expansion {
1942 return if parent_expansion.is_descendant_of(ctxt.outer()) {
1949 module_expansion = parent_expansion;
1955 fn resolve_ident_in_module(&mut self,
1959 ignore_unresolved_invocations: bool,
1962 -> Result<&'a NameBinding<'a>, Determinacy> {
1963 ident.ctxt = ident.ctxt.modern();
1964 let orig_current_module = self.current_module;
1965 if let Some(def) = ident.ctxt.adjust(module.expansion) {
1966 self.current_module = self.macro_def_scope(def);
1968 let result = self.resolve_ident_in_module_unadjusted(
1969 module, ident, ns, ignore_unresolved_invocations, record_used, span,
1971 self.current_module = orig_current_module;
1975 fn resolve_crate_root(&mut self, mut ctxt: SyntaxContext, legacy: bool) -> Module<'a> {
1976 let mark = if legacy {
1977 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1978 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1979 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
1980 ctxt.marks().into_iter().find(|&mark| mark.kind() != MarkKind::Modern)
1982 ctxt = ctxt.modern();
1983 ctxt.adjust(Mark::root())
1985 let module = match mark {
1986 Some(def) => self.macro_def_scope(def),
1987 None => return self.graph_root,
1989 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1992 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1993 let mut module = self.get_module(module.normal_ancestor_id);
1994 while module.span.ctxt().modern() != *ctxt {
1995 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1996 module = self.get_module(parent.normal_ancestor_id);
2003 // We maintain a list of value ribs and type ribs.
2005 // Simultaneously, we keep track of the current position in the module
2006 // graph in the `current_module` pointer. When we go to resolve a name in
2007 // the value or type namespaces, we first look through all the ribs and
2008 // then query the module graph. When we resolve a name in the module
2009 // namespace, we can skip all the ribs (since nested modules are not
2010 // allowed within blocks in Rust) and jump straight to the current module
2013 // Named implementations are handled separately. When we find a method
2014 // call, we consult the module node to find all of the implementations in
2015 // scope. This information is lazily cached in the module node. We then
2016 // generate a fake "implementation scope" containing all the
2017 // implementations thus found, for compatibility with old resolve pass.
2019 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2020 where F: FnOnce(&mut Resolver) -> T
2022 let id = self.definitions.local_def_id(id);
2023 let module = self.module_map.get(&id).cloned(); // clones a reference
2024 if let Some(module) = module {
2025 // Move down in the graph.
2026 let orig_module = replace(&mut self.current_module, module);
2027 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2028 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2030 self.finalize_current_module_macro_resolutions();
2033 self.current_module = orig_module;
2034 self.ribs[ValueNS].pop();
2035 self.ribs[TypeNS].pop();
2042 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2043 /// is returned by the given predicate function
2045 /// Stops after meeting a closure.
2046 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2047 where P: Fn(&Rib, Ident) -> Option<R>
2049 for rib in self.label_ribs.iter().rev() {
2052 // If an invocation of this macro created `ident`, give up on `ident`
2053 // and switch to `ident`'s source from the macro definition.
2054 MacroDefinition(def) => {
2055 if def == self.macro_def(ident.ctxt) {
2056 ident.ctxt.remove_mark();
2060 // Do not resolve labels across function boundary
2064 let r = pred(rib, ident);
2072 fn resolve_item(&mut self, item: &Item) {
2073 let name = item.ident.name;
2075 debug!("(resolving item) resolving {}", name);
2077 self.check_proc_macro_attrs(&item.attrs);
2080 ItemKind::Enum(_, ref generics) |
2081 ItemKind::Ty(_, ref generics) |
2082 ItemKind::Struct(_, ref generics) |
2083 ItemKind::Union(_, ref generics) |
2084 ItemKind::Fn(.., ref generics, _) => {
2085 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2086 |this| visit::walk_item(this, item));
2089 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2090 self.resolve_implementation(generics,
2096 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2097 // Create a new rib for the trait-wide type parameters.
2098 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2099 let local_def_id = this.definitions.local_def_id(item.id);
2100 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2101 this.visit_generics(generics);
2102 walk_list!(this, visit_ty_param_bound, bounds);
2104 for trait_item in trait_items {
2105 this.check_proc_macro_attrs(&trait_item.attrs);
2107 let type_parameters = HasTypeParameters(&trait_item.generics,
2108 TraitOrImplItemRibKind);
2109 this.with_type_parameter_rib(type_parameters, |this| {
2110 match trait_item.node {
2111 TraitItemKind::Const(ref ty, ref default) => {
2114 // Only impose the restrictions of
2115 // ConstRibKind for an actual constant
2116 // expression in a provided default.
2117 if let Some(ref expr) = *default{
2118 this.with_constant_rib(|this| {
2119 this.visit_expr(expr);
2123 TraitItemKind::Method(_, _) => {
2124 visit::walk_trait_item(this, trait_item)
2126 TraitItemKind::Type(..) => {
2127 visit::walk_trait_item(this, trait_item)
2129 TraitItemKind::Macro(_) => {
2130 panic!("unexpanded macro in resolve!")
2139 ItemKind::TraitAlias(ref generics, ref bounds) => {
2140 // Create a new rib for the trait-wide type parameters.
2141 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2142 let local_def_id = this.definitions.local_def_id(item.id);
2143 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2144 this.visit_generics(generics);
2145 walk_list!(this, visit_ty_param_bound, bounds);
2150 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2151 self.with_scope(item.id, |this| {
2152 visit::walk_item(this, item);
2156 ItemKind::Static(ref ty, _, ref expr) |
2157 ItemKind::Const(ref ty, ref expr) => {
2158 self.with_item_rib(|this| {
2160 this.with_constant_rib(|this| {
2161 this.visit_expr(expr);
2166 ItemKind::Use(ref use_tree) => {
2167 // Imports are resolved as global by default, add starting root segment.
2169 segments: use_tree.prefix.make_root().into_iter().collect(),
2170 span: use_tree.span,
2172 self.resolve_use_tree(item.id, use_tree, &path);
2175 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2176 // do nothing, these are just around to be encoded
2179 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2183 fn resolve_use_tree(&mut self, id: NodeId, use_tree: &ast::UseTree, prefix: &Path) {
2184 match use_tree.kind {
2185 ast::UseTreeKind::Nested(ref items) => {
2187 segments: prefix.segments
2189 .chain(use_tree.prefix.segments.iter())
2192 span: prefix.span.to(use_tree.prefix.span),
2195 if items.len() == 0 {
2196 // Resolve prefix of an import with empty braces (issue #28388).
2197 self.smart_resolve_path(id, None, &path, PathSource::ImportPrefix);
2199 for &(ref tree, nested_id) in items {
2200 self.resolve_use_tree(nested_id, tree, &path);
2204 ast::UseTreeKind::Simple(_) => {},
2205 ast::UseTreeKind::Glob => {},
2209 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2210 where F: FnOnce(&mut Resolver)
2212 match type_parameters {
2213 HasTypeParameters(generics, rib_kind) => {
2214 let mut function_type_rib = Rib::new(rib_kind);
2215 let mut seen_bindings = FxHashMap();
2216 for param in &generics.params {
2217 if let GenericParam::Type(ref type_parameter) = *param {
2218 let ident = type_parameter.ident.modern();
2219 debug!("with_type_parameter_rib: {}", type_parameter.id);
2221 if seen_bindings.contains_key(&ident) {
2222 let span = seen_bindings.get(&ident).unwrap();
2223 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2227 resolve_error(self, type_parameter.span, err);
2229 seen_bindings.entry(ident).or_insert(type_parameter.span);
2231 // plain insert (no renaming)
2232 let def_id = self.definitions.local_def_id(type_parameter.id);
2233 let def = Def::TyParam(def_id);
2234 function_type_rib.bindings.insert(ident, def);
2235 self.record_def(type_parameter.id, PathResolution::new(def));
2238 self.ribs[TypeNS].push(function_type_rib);
2241 NoTypeParameters => {
2248 if let HasTypeParameters(..) = type_parameters {
2249 self.ribs[TypeNS].pop();
2253 fn with_label_rib<F>(&mut self, f: F)
2254 where F: FnOnce(&mut Resolver)
2256 self.label_ribs.push(Rib::new(NormalRibKind));
2258 self.label_ribs.pop();
2261 fn with_item_rib<F>(&mut self, f: F)
2262 where F: FnOnce(&mut Resolver)
2264 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2265 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2267 self.ribs[TypeNS].pop();
2268 self.ribs[ValueNS].pop();
2271 fn with_constant_rib<F>(&mut self, f: F)
2272 where F: FnOnce(&mut Resolver)
2274 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2276 self.ribs[ValueNS].pop();
2279 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2280 where F: FnOnce(&mut Resolver) -> T
2282 // Handle nested impls (inside fn bodies)
2283 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2284 let result = f(self);
2285 self.current_self_type = previous_value;
2289 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2290 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2291 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2293 let mut new_val = None;
2294 let mut new_id = None;
2295 if let Some(trait_ref) = opt_trait_ref {
2296 let path: Vec<_> = trait_ref.path.segments.iter()
2297 .map(|seg| respan(seg.span, seg.identifier))
2299 let def = self.smart_resolve_path_fragment(
2303 trait_ref.path.span,
2304 PathSource::Trait(AliasPossibility::No)
2306 if def != Def::Err {
2307 new_id = Some(def.def_id());
2308 let span = trait_ref.path.span;
2309 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span) {
2310 new_val = Some((module, trait_ref.clone()));
2314 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2315 let result = f(self, new_id);
2316 self.current_trait_ref = original_trait_ref;
2320 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2321 where F: FnOnce(&mut Resolver)
2323 let mut self_type_rib = Rib::new(NormalRibKind);
2325 // plain insert (no renaming, types are not currently hygienic....)
2326 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2327 self.ribs[TypeNS].push(self_type_rib);
2329 self.ribs[TypeNS].pop();
2332 fn resolve_implementation(&mut self,
2333 generics: &Generics,
2334 opt_trait_reference: &Option<TraitRef>,
2337 impl_items: &[ImplItem]) {
2338 // If applicable, create a rib for the type parameters.
2339 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2340 // Dummy self type for better errors if `Self` is used in the trait path.
2341 this.with_self_rib(Def::SelfTy(None, None), |this| {
2342 // Resolve the trait reference, if necessary.
2343 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2344 let item_def_id = this.definitions.local_def_id(item_id);
2345 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2346 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2347 // Resolve type arguments in trait path
2348 visit::walk_trait_ref(this, trait_ref);
2350 // Resolve the self type.
2351 this.visit_ty(self_type);
2352 // Resolve the type parameters.
2353 this.visit_generics(generics);
2354 this.with_current_self_type(self_type, |this| {
2355 for impl_item in impl_items {
2356 this.check_proc_macro_attrs(&impl_item.attrs);
2357 this.resolve_visibility(&impl_item.vis);
2359 // We also need a new scope for the impl item type parameters.
2360 let type_parameters = HasTypeParameters(&impl_item.generics,
2361 TraitOrImplItemRibKind);
2362 this.with_type_parameter_rib(type_parameters, |this| {
2363 use self::ResolutionError::*;
2364 match impl_item.node {
2365 ImplItemKind::Const(..) => {
2366 // If this is a trait impl, ensure the const
2368 this.check_trait_item(impl_item.ident,
2371 |n, s| ConstNotMemberOfTrait(n, s));
2372 this.with_constant_rib(|this|
2373 visit::walk_impl_item(this, impl_item)
2376 ImplItemKind::Method(_, _) => {
2377 // If this is a trait impl, ensure the method
2379 this.check_trait_item(impl_item.ident,
2382 |n, s| MethodNotMemberOfTrait(n, s));
2384 visit::walk_impl_item(this, impl_item);
2386 ImplItemKind::Type(ref ty) => {
2387 // If this is a trait impl, ensure the type
2389 this.check_trait_item(impl_item.ident,
2392 |n, s| TypeNotMemberOfTrait(n, s));
2396 ImplItemKind::Macro(_) =>
2397 panic!("unexpanded macro in resolve!"),
2408 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2409 where F: FnOnce(Name, &str) -> ResolutionError
2411 // If there is a TraitRef in scope for an impl, then the method must be in the
2413 if let Some((module, _)) = self.current_trait_ref {
2414 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2415 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2416 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2421 fn resolve_local(&mut self, local: &Local) {
2422 // Resolve the type.
2423 walk_list!(self, visit_ty, &local.ty);
2425 // Resolve the initializer.
2426 walk_list!(self, visit_expr, &local.init);
2428 // Resolve the pattern.
2429 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2432 // build a map from pattern identifiers to binding-info's.
2433 // this is done hygienically. This could arise for a macro
2434 // that expands into an or-pattern where one 'x' was from the
2435 // user and one 'x' came from the macro.
2436 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2437 let mut binding_map = FxHashMap();
2439 pat.walk(&mut |pat| {
2440 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2441 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2442 Some(Def::Local(..)) => true,
2445 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2446 binding_map.insert(ident.node, binding_info);
2455 // check that all of the arms in an or-pattern have exactly the
2456 // same set of bindings, with the same binding modes for each.
2457 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2458 if pats.is_empty() {
2462 let mut missing_vars = FxHashMap();
2463 let mut inconsistent_vars = FxHashMap();
2464 for (i, p) in pats.iter().enumerate() {
2465 let map_i = self.binding_mode_map(&p);
2467 for (j, q) in pats.iter().enumerate() {
2472 let map_j = self.binding_mode_map(&q);
2473 for (&key, &binding_i) in &map_i {
2474 if map_j.len() == 0 { // Account for missing bindings when
2475 let binding_error = missing_vars // map_j has none.
2477 .or_insert(BindingError {
2479 origin: BTreeSet::new(),
2480 target: BTreeSet::new(),
2482 binding_error.origin.insert(binding_i.span);
2483 binding_error.target.insert(q.span);
2485 for (&key_j, &binding_j) in &map_j {
2486 match map_i.get(&key_j) {
2487 None => { // missing binding
2488 let binding_error = missing_vars
2490 .or_insert(BindingError {
2492 origin: BTreeSet::new(),
2493 target: BTreeSet::new(),
2495 binding_error.origin.insert(binding_j.span);
2496 binding_error.target.insert(p.span);
2498 Some(binding_i) => { // check consistent binding
2499 if binding_i.binding_mode != binding_j.binding_mode {
2502 .or_insert((binding_j.span, binding_i.span));
2510 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2511 missing_vars.sort();
2512 for (_, v) in missing_vars {
2514 *v.origin.iter().next().unwrap(),
2515 ResolutionError::VariableNotBoundInPattern(v));
2517 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2518 inconsistent_vars.sort();
2519 for (name, v) in inconsistent_vars {
2520 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2524 fn resolve_arm(&mut self, arm: &Arm) {
2525 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2527 let mut bindings_list = FxHashMap();
2528 for pattern in &arm.pats {
2529 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2532 // This has to happen *after* we determine which pat_idents are variants
2533 self.check_consistent_bindings(&arm.pats);
2535 walk_list!(self, visit_expr, &arm.guard);
2536 self.visit_expr(&arm.body);
2538 self.ribs[ValueNS].pop();
2541 fn resolve_block(&mut self, block: &Block) {
2542 debug!("(resolving block) entering block");
2543 // Move down in the graph, if there's an anonymous module rooted here.
2544 let orig_module = self.current_module;
2545 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2547 let mut num_macro_definition_ribs = 0;
2548 if let Some(anonymous_module) = anonymous_module {
2549 debug!("(resolving block) found anonymous module, moving down");
2550 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2551 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2552 self.current_module = anonymous_module;
2553 self.finalize_current_module_macro_resolutions();
2555 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2558 // Descend into the block.
2559 for stmt in &block.stmts {
2560 if let ast::StmtKind::Item(ref item) = stmt.node {
2561 if let ast::ItemKind::MacroDef(..) = item.node {
2562 num_macro_definition_ribs += 1;
2563 let def = self.definitions.local_def_id(item.id);
2564 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2565 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2569 self.visit_stmt(stmt);
2573 self.current_module = orig_module;
2574 for _ in 0 .. num_macro_definition_ribs {
2575 self.ribs[ValueNS].pop();
2576 self.label_ribs.pop();
2578 self.ribs[ValueNS].pop();
2579 if let Some(_) = anonymous_module {
2580 self.ribs[TypeNS].pop();
2582 debug!("(resolving block) leaving block");
2585 fn fresh_binding(&mut self,
2586 ident: &SpannedIdent,
2588 outer_pat_id: NodeId,
2589 pat_src: PatternSource,
2590 bindings: &mut FxHashMap<Ident, NodeId>)
2592 // Add the binding to the local ribs, if it
2593 // doesn't already exist in the bindings map. (We
2594 // must not add it if it's in the bindings map
2595 // because that breaks the assumptions later
2596 // passes make about or-patterns.)
2597 let mut def = Def::Local(pat_id);
2598 match bindings.get(&ident.node).cloned() {
2599 Some(id) if id == outer_pat_id => {
2600 // `Variant(a, a)`, error
2604 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2605 &ident.node.name.as_str())
2608 Some(..) if pat_src == PatternSource::FnParam => {
2609 // `fn f(a: u8, a: u8)`, error
2613 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2614 &ident.node.name.as_str())
2617 Some(..) if pat_src == PatternSource::Match ||
2618 pat_src == PatternSource::IfLet ||
2619 pat_src == PatternSource::WhileLet => {
2620 // `Variant1(a) | Variant2(a)`, ok
2621 // Reuse definition from the first `a`.
2622 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2625 span_bug!(ident.span, "two bindings with the same name from \
2626 unexpected pattern source {:?}", pat_src);
2629 // A completely fresh binding, add to the lists if it's valid.
2630 if ident.node.name != keywords::Invalid.name() {
2631 bindings.insert(ident.node, outer_pat_id);
2632 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2637 PathResolution::new(def)
2640 fn resolve_pattern(&mut self,
2642 pat_src: PatternSource,
2643 // Maps idents to the node ID for the
2644 // outermost pattern that binds them.
2645 bindings: &mut FxHashMap<Ident, NodeId>) {
2646 // Visit all direct subpatterns of this pattern.
2647 let outer_pat_id = pat.id;
2648 pat.walk(&mut |pat| {
2650 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2651 // First try to resolve the identifier as some existing
2652 // entity, then fall back to a fresh binding.
2653 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2655 .and_then(LexicalScopeBinding::item);
2656 let resolution = binding.map(NameBinding::def).and_then(|def| {
2657 let is_syntactic_ambiguity = opt_pat.is_none() &&
2658 bmode == BindingMode::ByValue(Mutability::Immutable);
2660 Def::StructCtor(_, CtorKind::Const) |
2661 Def::VariantCtor(_, CtorKind::Const) |
2662 Def::Const(..) if is_syntactic_ambiguity => {
2663 // Disambiguate in favor of a unit struct/variant
2664 // or constant pattern.
2665 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2666 Some(PathResolution::new(def))
2668 Def::StructCtor(..) | Def::VariantCtor(..) |
2669 Def::Const(..) | Def::Static(..) => {
2670 // This is unambiguously a fresh binding, either syntactically
2671 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2672 // to something unusable as a pattern (e.g. constructor function),
2673 // but we still conservatively report an error, see
2674 // issues/33118#issuecomment-233962221 for one reason why.
2678 ResolutionError::BindingShadowsSomethingUnacceptable(
2679 pat_src.descr(), ident.node.name, binding.unwrap())
2683 Def::Fn(..) | Def::Err => {
2684 // These entities are explicitly allowed
2685 // to be shadowed by fresh bindings.
2689 span_bug!(ident.span, "unexpected definition for an \
2690 identifier in pattern: {:?}", def);
2693 }).unwrap_or_else(|| {
2694 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2697 self.record_def(pat.id, resolution);
2700 PatKind::TupleStruct(ref path, ..) => {
2701 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2704 PatKind::Path(ref qself, ref path) => {
2705 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2708 PatKind::Struct(ref path, ..) => {
2709 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2717 visit::walk_pat(self, pat);
2720 // High-level and context dependent path resolution routine.
2721 // Resolves the path and records the resolution into definition map.
2722 // If resolution fails tries several techniques to find likely
2723 // resolution candidates, suggest imports or other help, and report
2724 // errors in user friendly way.
2725 fn smart_resolve_path(&mut self,
2727 qself: Option<&QSelf>,
2731 let segments = &path.segments.iter()
2732 .map(|seg| respan(seg.span, seg.identifier))
2733 .collect::<Vec<_>>();
2734 self.smart_resolve_path_fragment(id, qself, segments, path.span, source)
2737 fn smart_resolve_path_fragment(&mut self,
2739 qself: Option<&QSelf>,
2740 path: &[SpannedIdent],
2744 let ident_span = path.last().map_or(span, |ident| ident.span);
2745 let ns = source.namespace();
2746 let is_expected = &|def| source.is_expected(def);
2747 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2749 // Base error is amended with one short label and possibly some longer helps/notes.
2750 let report_errors = |this: &mut Self, def: Option<Def>| {
2751 // Make the base error.
2752 let expected = source.descr_expected();
2753 let path_str = names_to_string(path);
2754 let code = source.error_code(def.is_some());
2755 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2756 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2757 format!("not a {}", expected),
2760 let item_str = path[path.len() - 1].node;
2761 let item_span = path[path.len() - 1].span;
2762 let (mod_prefix, mod_str) = if path.len() == 1 {
2763 (format!(""), format!("this scope"))
2764 } else if path.len() == 2 && path[0].node.name == keywords::CrateRoot.name() {
2765 (format!(""), format!("the crate root"))
2767 let mod_path = &path[..path.len() - 1];
2768 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2769 PathResult::Module(module) => module.def(),
2771 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2772 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2774 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2775 format!("not found in {}", mod_str),
2778 let code = DiagnosticId::Error(code.into());
2779 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2781 // Emit special messages for unresolved `Self` and `self`.
2782 if is_self_type(path, ns) {
2783 __diagnostic_used!(E0411);
2784 err.code(DiagnosticId::Error("E0411".into()));
2785 err.span_label(span, "`Self` is only available in traits and impls");
2786 return (err, Vec::new());
2788 if is_self_value(path, ns) {
2789 __diagnostic_used!(E0424);
2790 err.code(DiagnosticId::Error("E0424".into()));
2791 err.span_label(span, format!("`self` value is only available in \
2792 methods with `self` parameter"));
2793 return (err, Vec::new());
2796 // Try to lookup the name in more relaxed fashion for better error reporting.
2797 let ident = *path.last().unwrap();
2798 let candidates = this.lookup_import_candidates(ident.node.name, ns, is_expected);
2799 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2800 let enum_candidates =
2801 this.lookup_import_candidates(ident.node.name, ns, is_enum_variant);
2802 let mut enum_candidates = enum_candidates.iter()
2803 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2804 enum_candidates.sort();
2805 for (sp, variant_path, enum_path) in enum_candidates {
2807 let msg = format!("there is an enum variant `{}`, \
2813 err.span_suggestion(span, "you can try using the variant's enum",
2818 if path.len() == 1 && this.self_type_is_available(span) {
2819 if let Some(candidate) = this.lookup_assoc_candidate(ident.node, ns, is_expected) {
2820 let self_is_available = this.self_value_is_available(path[0].node.ctxt, span);
2822 AssocSuggestion::Field => {
2823 err.span_suggestion(span, "try",
2824 format!("self.{}", path_str));
2825 if !self_is_available {
2826 err.span_label(span, format!("`self` value is only available in \
2827 methods with `self` parameter"));
2830 AssocSuggestion::MethodWithSelf if self_is_available => {
2831 err.span_suggestion(span, "try",
2832 format!("self.{}", path_str));
2834 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2835 err.span_suggestion(span, "try",
2836 format!("Self::{}", path_str));
2839 return (err, candidates);
2843 let mut levenshtein_worked = false;
2846 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2847 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2848 levenshtein_worked = true;
2851 // Try context dependent help if relaxed lookup didn't work.
2852 if let Some(def) = def {
2853 match (def, source) {
2854 (Def::Macro(..), _) => {
2855 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2856 return (err, candidates);
2858 (Def::TyAlias(..), PathSource::Trait(_)) => {
2859 err.span_label(span, "type aliases cannot be used for traits");
2860 return (err, candidates);
2862 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2863 ExprKind::Field(_, ident) => {
2864 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2865 path_str, ident.node));
2866 return (err, candidates);
2868 ExprKind::MethodCall(ref segment, ..) => {
2869 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2870 path_str, segment.identifier));
2871 return (err, candidates);
2875 (Def::Enum(..), PathSource::TupleStruct)
2876 | (Def::Enum(..), PathSource::Expr(..)) => {
2877 if let Some(variants) = this.collect_enum_variants(def) {
2878 err.note(&format!("did you mean to use one \
2879 of the following variants?\n{}",
2881 .map(|suggestion| path_names_to_string(suggestion))
2882 .map(|suggestion| format!("- `{}`", suggestion))
2883 .collect::<Vec<_>>()
2887 err.note("did you mean to use one of the enum's variants?");
2889 return (err, candidates);
2891 (Def::Struct(def_id), _) if ns == ValueNS => {
2892 if let Some((ctor_def, ctor_vis))
2893 = this.struct_constructors.get(&def_id).cloned() {
2894 let accessible_ctor = this.is_accessible(ctor_vis);
2895 if is_expected(ctor_def) && !accessible_ctor {
2896 err.span_label(span, format!("constructor is not visible \
2897 here due to private fields"));
2900 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2903 return (err, candidates);
2905 (Def::Union(..), _) |
2906 (Def::Variant(..), _) |
2907 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
2908 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2910 return (err, candidates);
2912 (Def::SelfTy(..), _) if ns == ValueNS => {
2913 err.span_label(span, fallback_label);
2914 err.note("can't use `Self` as a constructor, you must use the \
2915 implemented struct");
2916 return (err, candidates);
2918 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
2919 err.note("can't use a type alias as a constructor");
2920 return (err, candidates);
2927 if !levenshtein_worked {
2928 err.span_label(base_span, fallback_label);
2929 this.type_ascription_suggestion(&mut err, base_span);
2933 let report_errors = |this: &mut Self, def: Option<Def>| {
2934 let (err, candidates) = report_errors(this, def);
2935 let def_id = this.current_module.normal_ancestor_id;
2936 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
2937 let better = def.is_some();
2938 this.use_injections.push(UseError { err, candidates, node_id, better });
2939 err_path_resolution()
2942 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2943 source.defer_to_typeck(),
2944 source.global_by_default()) {
2945 Some(resolution) if resolution.unresolved_segments() == 0 => {
2946 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2949 // Add a temporary hack to smooth the transition to new struct ctor
2950 // visibility rules. See #38932 for more details.
2952 if let Def::Struct(def_id) = resolution.base_def() {
2953 if let Some((ctor_def, ctor_vis))
2954 = self.struct_constructors.get(&def_id).cloned() {
2955 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2956 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2957 self.session.buffer_lint(lint, id, span,
2958 "private struct constructors are not usable through \
2959 re-exports in outer modules",
2961 res = Some(PathResolution::new(ctor_def));
2966 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2969 Some(resolution) if source.defer_to_typeck() => {
2970 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2971 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2972 // it needs to be added to the trait map.
2974 let item_name = path.last().unwrap().node;
2975 let traits = self.get_traits_containing_item(item_name, ns);
2976 self.trait_map.insert(id, traits);
2980 _ => report_errors(self, None)
2983 if let PathSource::TraitItem(..) = source {} else {
2984 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2985 self.record_def(id, resolution);
2990 fn type_ascription_suggestion(&self,
2991 err: &mut DiagnosticBuilder,
2993 debug!("type_ascription_suggetion {:?}", base_span);
2994 let cm = self.session.codemap();
2995 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
2996 if let Some(sp) = self.current_type_ascription.last() {
2998 loop { // try to find the `:`, bail on first non-':'/non-whitespace
2999 sp = cm.next_point(sp);
3000 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3001 debug!("snippet {:?}", snippet);
3002 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3003 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3004 debug!("{:?} {:?}", line_sp, line_base_sp);
3006 err.span_label(base_span,
3007 "expecting a type here because of type ascription");
3008 if line_sp != line_base_sp {
3009 err.span_suggestion_short(sp,
3010 "did you mean to use `;` here instead?",
3014 } else if snippet.trim().len() != 0 {
3015 debug!("tried to find type ascription `:` token, couldn't find it");
3025 fn self_type_is_available(&mut self, span: Span) -> bool {
3026 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3027 TypeNS, false, span);
3028 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3031 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
3032 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
3033 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
3034 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3037 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3038 fn resolve_qpath_anywhere(&mut self,
3040 qself: Option<&QSelf>,
3041 path: &[SpannedIdent],
3042 primary_ns: Namespace,
3044 defer_to_typeck: bool,
3045 global_by_default: bool)
3046 -> Option<PathResolution> {
3047 let mut fin_res = None;
3048 // FIXME: can't resolve paths in macro namespace yet, macros are
3049 // processed by the little special hack below.
3050 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3051 if i == 0 || ns != primary_ns {
3052 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
3053 // If defer_to_typeck, then resolution > no resolution,
3054 // otherwise full resolution > partial resolution > no resolution.
3055 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3057 res => if fin_res.is_none() { fin_res = res },
3061 let is_global = self.global_macros.get(&path[0].node.name).cloned()
3062 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3063 if primary_ns != MacroNS && (is_global ||
3064 self.macro_names.contains(&path[0].node.modern())) {
3065 // Return some dummy definition, it's enough for error reporting.
3067 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3073 /// Handles paths that may refer to associated items.
3074 fn resolve_qpath(&mut self,
3076 qself: Option<&QSelf>,
3077 path: &[SpannedIdent],
3080 global_by_default: bool)
3081 -> Option<PathResolution> {
3082 if let Some(qself) = qself {
3083 if qself.position == 0 {
3084 // FIXME: Create some fake resolution that can't possibly be a type.
3085 return Some(PathResolution::with_unresolved_segments(
3086 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3089 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
3090 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3091 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
3092 span, PathSource::TraitItem(ns));
3093 return Some(PathResolution::with_unresolved_segments(
3094 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3098 let result = match self.resolve_path(&path, Some(ns), true, span) {
3099 PathResult::NonModule(path_res) => path_res,
3100 PathResult::Module(module) if !module.is_normal() => {
3101 PathResolution::new(module.def().unwrap())
3103 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3104 // don't report an error right away, but try to fallback to a primitive type.
3105 // So, we are still able to successfully resolve something like
3107 // use std::u8; // bring module u8 in scope
3108 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3109 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3110 // // not to non-existent std::u8::max_value
3113 // Such behavior is required for backward compatibility.
3114 // The same fallback is used when `a` resolves to nothing.
3115 PathResult::Module(..) | PathResult::Failed(..)
3116 if (ns == TypeNS || path.len() > 1) &&
3117 self.primitive_type_table.primitive_types
3118 .contains_key(&path[0].node.name) => {
3119 let prim = self.primitive_type_table.primitive_types[&path[0].node.name];
3120 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3122 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
3123 PathResult::Failed(span, msg, false) => {
3124 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3125 err_path_resolution()
3127 PathResult::Failed(..) => return None,
3128 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3131 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3132 path[0].node.name != keywords::CrateRoot.name() &&
3133 path[0].node.name != keywords::DollarCrate.name() {
3134 let unqualified_result = {
3135 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
3136 PathResult::NonModule(path_res) => path_res.base_def(),
3137 PathResult::Module(module) => module.def().unwrap(),
3138 _ => return Some(result),
3141 if result.base_def() == unqualified_result {
3142 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3143 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3150 fn resolve_path(&mut self,
3151 path: &[SpannedIdent],
3152 opt_ns: Option<Namespace>, // `None` indicates a module path
3156 let mut module = None;
3157 let mut allow_super = true;
3159 for (i, &ident) in path.iter().enumerate() {
3160 debug!("resolve_path ident {} {:?}", i, ident);
3161 let is_last = i == path.len() - 1;
3162 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3163 let name = ident.node.name;
3165 if i == 0 && ns == TypeNS && name == keywords::SelfValue.name() {
3166 let mut ctxt = ident.node.ctxt.modern();
3167 module = Some(self.resolve_self(&mut ctxt, self.current_module));
3169 } else if allow_super && ns == TypeNS && name == keywords::Super.name() {
3170 let mut ctxt = ident.node.ctxt.modern();
3171 let self_module = match i {
3172 0 => self.resolve_self(&mut ctxt, self.current_module),
3173 _ => module.unwrap(),
3175 if let Some(parent) = self_module.parent {
3176 module = Some(self.resolve_self(&mut ctxt, parent));
3179 let msg = "There are too many initial `super`s.".to_string();
3180 return PathResult::Failed(ident.span, msg, false);
3182 } else if i == 0 && ns == TypeNS && name == keywords::Extern.name() {
3185 allow_super = false;
3188 if (i == 0 && name == keywords::CrateRoot.name()) ||
3189 (i == 1 && name == keywords::Crate.name() &&
3190 path[0].node.name == keywords::CrateRoot.name()) {
3191 // `::a::b` or `::crate::a::b`
3192 module = Some(self.resolve_crate_root(ident.node.ctxt, false));
3194 } else if i == 0 && name == keywords::DollarCrate.name() {
3196 module = Some(self.resolve_crate_root(ident.node.ctxt, true));
3198 } else if i == 1 && !token::is_path_segment_keyword(ident.node) {
3199 let prev_name = path[0].node.name;
3200 if prev_name == keywords::Extern.name() ||
3201 prev_name == keywords::CrateRoot.name() &&
3202 self.session.features_untracked().extern_absolute_paths {
3203 // `::extern_crate::a::b`
3204 let crate_id = self.crate_loader.resolve_crate_from_path(name, ident.span);
3206 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3207 self.populate_module_if_necessary(crate_root);
3208 module = Some(crate_root);
3214 // Report special messages for path segment keywords in wrong positions.
3215 if name == keywords::CrateRoot.name() && i != 0 ||
3216 name == keywords::DollarCrate.name() && i != 0 ||
3217 name == keywords::SelfValue.name() && i != 0 ||
3218 name == keywords::SelfType.name() && i != 0 ||
3219 name == keywords::Super.name() && i != 0 ||
3220 name == keywords::Extern.name() && i != 0 ||
3221 name == keywords::Crate.name() && i != 1 &&
3222 path[0].node.name != keywords::CrateRoot.name() {
3223 let name_str = if name == keywords::CrateRoot.name() {
3224 format!("crate root")
3226 format!("`{}`", name)
3228 let msg = if i == 1 && path[0].node.name == keywords::CrateRoot.name() {
3229 format!("global paths cannot start with {}", name_str)
3230 } else if i == 0 && name == keywords::Crate.name() {
3231 format!("{} can only be used in absolute paths", name_str)
3233 format!("{} in paths can only be used in start position", name_str)
3235 return PathResult::Failed(ident.span, msg, false);
3238 let binding = if let Some(module) = module {
3239 self.resolve_ident_in_module(module, ident.node, ns, false, record_used, path_span)
3240 } else if opt_ns == Some(MacroNS) {
3241 self.resolve_lexical_macro_path_segment(ident.node, ns, record_used, path_span)
3242 .map(MacroBinding::binding)
3244 match self.resolve_ident_in_lexical_scope(ident.node, ns, record_used, path_span) {
3245 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3246 Some(LexicalScopeBinding::Def(def))
3247 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3248 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3252 _ => Err(if record_used { Determined } else { Undetermined }),
3258 let def = binding.def();
3259 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3260 if let Some(next_module) = binding.module() {
3261 module = Some(next_module);
3262 } else if def == Def::Err {
3263 return PathResult::NonModule(err_path_resolution());
3264 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3265 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3266 def, path.len() - i - 1
3269 return PathResult::Failed(ident.span,
3270 format!("Not a module `{}`", ident.node),
3274 Err(Undetermined) => return PathResult::Indeterminate,
3275 Err(Determined) => {
3276 if let Some(module) = module {
3277 if opt_ns.is_some() && !module.is_normal() {
3278 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3279 module.def().unwrap(), path.len() - i
3283 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
3284 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3285 let mut candidates =
3286 self.lookup_import_candidates(name, TypeNS, is_mod);
3287 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
3288 if let Some(candidate) = candidates.get(0) {
3289 format!("Did you mean `{}`?", candidate.path)
3291 format!("Maybe a missing `extern crate {};`?", ident.node)
3294 format!("Use of undeclared type or module `{}`", ident.node)
3296 format!("Could not find `{}` in `{}`", ident.node, path[i - 1].node)
3298 return PathResult::Failed(ident.span, msg, is_last);
3303 PathResult::Module(module.unwrap_or(self.graph_root))
3306 // Resolve a local definition, potentially adjusting for closures.
3307 fn adjust_local_def(&mut self,
3312 span: Span) -> Def {
3313 let ribs = &self.ribs[ns][rib_index + 1..];
3315 // An invalid forward use of a type parameter from a previous default.
3316 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3318 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3320 assert_eq!(def, Def::Err);
3326 span_bug!(span, "unexpected {:?} in bindings", def)
3328 Def::Local(node_id) => {
3331 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3332 ForwardTyParamBanRibKind => {
3333 // Nothing to do. Continue.
3335 ClosureRibKind(function_id) => {
3338 let seen = self.freevars_seen
3340 .or_insert_with(|| NodeMap());
3341 if let Some(&index) = seen.get(&node_id) {
3342 def = Def::Upvar(node_id, index, function_id);
3345 let vec = self.freevars
3347 .or_insert_with(|| vec![]);
3348 let depth = vec.len();
3349 def = Def::Upvar(node_id, depth, function_id);
3356 seen.insert(node_id, depth);
3359 ItemRibKind | TraitOrImplItemRibKind => {
3360 // This was an attempt to access an upvar inside a
3361 // named function item. This is not allowed, so we
3364 resolve_error(self, span,
3365 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3369 ConstantItemRibKind => {
3370 // Still doesn't deal with upvars
3372 resolve_error(self, span,
3373 ResolutionError::AttemptToUseNonConstantValueInConstant);
3380 Def::TyParam(..) | Def::SelfTy(..) => {
3383 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3384 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3385 ConstantItemRibKind => {
3386 // Nothing to do. Continue.
3389 // This was an attempt to use a type parameter outside
3392 resolve_error(self, span,
3393 ResolutionError::TypeParametersFromOuterFunction(def));
3405 fn lookup_assoc_candidate<FilterFn>(&mut self,
3408 filter_fn: FilterFn)
3409 -> Option<AssocSuggestion>
3410 where FilterFn: Fn(Def) -> bool
3412 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3414 TyKind::Path(None, _) => Some(t.id),
3415 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3416 // This doesn't handle the remaining `Ty` variants as they are not
3417 // that commonly the self_type, it might be interesting to provide
3418 // support for those in future.
3423 // Fields are generally expected in the same contexts as locals.
3424 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3425 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3426 // Look for a field with the same name in the current self_type.
3427 if let Some(resolution) = self.def_map.get(&node_id) {
3428 match resolution.base_def() {
3429 Def::Struct(did) | Def::Union(did)
3430 if resolution.unresolved_segments() == 0 => {
3431 if let Some(field_names) = self.field_names.get(&did) {
3432 if field_names.iter().any(|&field_name| ident.name == field_name) {
3433 return Some(AssocSuggestion::Field);
3443 // Look for associated items in the current trait.
3444 if let Some((module, _)) = self.current_trait_ref {
3445 if let Ok(binding) =
3446 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3447 let def = binding.def();
3449 return Some(if self.has_self.contains(&def.def_id()) {
3450 AssocSuggestion::MethodWithSelf
3452 AssocSuggestion::AssocItem
3461 fn lookup_typo_candidate<FilterFn>(&mut self,
3462 path: &[SpannedIdent],
3464 filter_fn: FilterFn,
3467 where FilterFn: Fn(Def) -> bool
3469 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3470 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3471 if let Some(binding) = resolution.borrow().binding {
3472 if filter_fn(binding.def()) {
3473 names.push(ident.name);
3479 let mut names = Vec::new();
3480 if path.len() == 1 {
3481 // Search in lexical scope.
3482 // Walk backwards up the ribs in scope and collect candidates.
3483 for rib in self.ribs[ns].iter().rev() {
3484 // Locals and type parameters
3485 for (ident, def) in &rib.bindings {
3486 if filter_fn(*def) {
3487 names.push(ident.name);
3491 if let ModuleRibKind(module) = rib.kind {
3492 // Items from this module
3493 add_module_candidates(module, &mut names);
3495 if let ModuleKind::Block(..) = module.kind {
3496 // We can see through blocks
3498 // Items from the prelude
3499 if let Some(prelude) = self.prelude {
3500 if !module.no_implicit_prelude {
3501 add_module_candidates(prelude, &mut names);
3508 // Add primitive types to the mix
3509 if filter_fn(Def::PrimTy(TyBool)) {
3510 for (name, _) in &self.primitive_type_table.primitive_types {
3515 // Search in module.
3516 let mod_path = &path[..path.len() - 1];
3517 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3519 add_module_candidates(module, &mut names);
3523 let name = path[path.len() - 1].node.name;
3524 // Make sure error reporting is deterministic.
3525 names.sort_by_key(|name| name.as_str());
3526 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3527 Some(found) if found != name => Some(found),
3532 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3533 where F: FnOnce(&mut Resolver)
3535 if let Some(label) = label {
3536 let def = Def::Label(id);
3537 self.with_label_rib(|this| {
3538 this.label_ribs.last_mut().unwrap().bindings.insert(label.ident, def);
3546 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3547 self.with_resolved_label(label, id, |this| this.visit_block(block));
3550 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3551 // First, record candidate traits for this expression if it could
3552 // result in the invocation of a method call.
3554 self.record_candidate_traits_for_expr_if_necessary(expr);
3556 // Next, resolve the node.
3558 ExprKind::Path(ref qself, ref path) => {
3559 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3560 visit::walk_expr(self, expr);
3563 ExprKind::Struct(ref path, ..) => {
3564 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3565 visit::walk_expr(self, expr);
3568 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3569 match self.search_label(label.ident, |rib, id| rib.bindings.get(&id).cloned()) {
3571 // Search again for close matches...
3572 // Picks the first label that is "close enough", which is not necessarily
3573 // the closest match
3574 let close_match = self.search_label(label.ident, |rib, ident| {
3575 let names = rib.bindings.iter().map(|(id, _)| &id.name);
3576 find_best_match_for_name(names, &*ident.name.as_str(), None)
3578 self.record_def(expr.id, err_path_resolution());
3581 ResolutionError::UndeclaredLabel(&label.ident.name.as_str(),
3584 Some(def @ Def::Label(_)) => {
3585 // Since this def is a label, it is never read.
3586 self.record_def(expr.id, PathResolution::new(def));
3589 span_bug!(expr.span, "label wasn't mapped to a label def!");
3593 // visit `break` argument if any
3594 visit::walk_expr(self, expr);
3597 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
3598 self.visit_expr(subexpression);
3600 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3601 let mut bindings_list = FxHashMap();
3603 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
3605 // This has to happen *after* we determine which pat_idents are variants
3606 self.check_consistent_bindings(pats);
3607 self.visit_block(if_block);
3608 self.ribs[ValueNS].pop();
3610 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3613 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3615 ExprKind::While(ref subexpression, ref block, label) => {
3616 self.with_resolved_label(label, expr.id, |this| {
3617 this.visit_expr(subexpression);
3618 this.visit_block(block);
3622 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
3623 self.with_resolved_label(label, expr.id, |this| {
3624 this.visit_expr(subexpression);
3625 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3626 let mut bindings_list = FxHashMap();
3628 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
3630 // This has to happen *after* we determine which pat_idents are variants
3631 this.check_consistent_bindings(pats);
3632 this.visit_block(block);
3633 this.ribs[ValueNS].pop();
3637 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3638 self.visit_expr(subexpression);
3639 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3640 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3642 self.resolve_labeled_block(label, expr.id, block);
3644 self.ribs[ValueNS].pop();
3647 // Equivalent to `visit::walk_expr` + passing some context to children.
3648 ExprKind::Field(ref subexpression, _) => {
3649 self.resolve_expr(subexpression, Some(expr));
3651 ExprKind::MethodCall(ref segment, ref arguments) => {
3652 let mut arguments = arguments.iter();
3653 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3654 for argument in arguments {
3655 self.resolve_expr(argument, None);
3657 self.visit_path_segment(expr.span, segment);
3660 ExprKind::Repeat(ref element, ref count) => {
3661 self.visit_expr(element);
3662 self.with_constant_rib(|this| {
3663 this.visit_expr(count);
3666 ExprKind::Call(ref callee, ref arguments) => {
3667 self.resolve_expr(callee, Some(expr));
3668 for argument in arguments {
3669 self.resolve_expr(argument, None);
3672 ExprKind::Type(ref type_expr, _) => {
3673 self.current_type_ascription.push(type_expr.span);
3674 visit::walk_expr(self, expr);
3675 self.current_type_ascription.pop();
3678 visit::walk_expr(self, expr);
3683 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3685 ExprKind::Field(_, name) => {
3686 // FIXME(#6890): Even though you can't treat a method like a
3687 // field, we need to add any trait methods we find that match
3688 // the field name so that we can do some nice error reporting
3689 // later on in typeck.
3690 let traits = self.get_traits_containing_item(name.node, ValueNS);
3691 self.trait_map.insert(expr.id, traits);
3693 ExprKind::MethodCall(ref segment, ..) => {
3694 debug!("(recording candidate traits for expr) recording traits for {}",
3696 let traits = self.get_traits_containing_item(segment.identifier, ValueNS);
3697 self.trait_map.insert(expr.id, traits);
3705 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
3706 -> Vec<TraitCandidate> {
3707 debug!("(getting traits containing item) looking for '{}'", ident.name);
3709 let mut found_traits = Vec::new();
3710 // Look for the current trait.
3711 if let Some((module, _)) = self.current_trait_ref {
3712 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3713 let def_id = module.def_id().unwrap();
3714 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3718 ident.ctxt = ident.ctxt.modern();
3719 let mut search_module = self.current_module;
3721 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3723 unwrap_or!(self.hygienic_lexical_parent(search_module, &mut ident.ctxt), break);
3726 if let Some(prelude) = self.prelude {
3727 if !search_module.no_implicit_prelude {
3728 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3735 fn get_traits_in_module_containing_item(&mut self,
3739 found_traits: &mut Vec<TraitCandidate>) {
3740 let mut traits = module.traits.borrow_mut();
3741 if traits.is_none() {
3742 let mut collected_traits = Vec::new();
3743 module.for_each_child(|name, ns, binding| {
3744 if ns != TypeNS { return }
3745 if let Def::Trait(_) = binding.def() {
3746 collected_traits.push((name, binding));
3749 *traits = Some(collected_traits.into_boxed_slice());
3752 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3753 let module = binding.module().unwrap();
3754 let mut ident = ident;
3755 if ident.ctxt.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
3758 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
3760 let import_id = match binding.kind {
3761 NameBindingKind::Import { directive, .. } => {
3762 self.maybe_unused_trait_imports.insert(directive.id);
3763 self.add_to_glob_map(directive.id, trait_name);
3768 let trait_def_id = module.def_id().unwrap();
3769 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3774 /// When name resolution fails, this method can be used to look up candidate
3775 /// entities with the expected name. It allows filtering them using the
3776 /// supplied predicate (which should be used to only accept the types of
3777 /// definitions expected e.g. traits). The lookup spans across all crates.
3779 /// NOTE: The method does not look into imports, but this is not a problem,
3780 /// since we report the definitions (thus, the de-aliased imports).
3781 fn lookup_import_candidates<FilterFn>(&mut self,
3783 namespace: Namespace,
3784 filter_fn: FilterFn)
3785 -> Vec<ImportSuggestion>
3786 where FilterFn: Fn(Def) -> bool
3788 let mut candidates = Vec::new();
3789 let mut worklist = Vec::new();
3790 let mut seen_modules = FxHashSet();
3791 worklist.push((self.graph_root, Vec::new(), false));
3793 while let Some((in_module,
3795 in_module_is_extern)) = worklist.pop() {
3796 self.populate_module_if_necessary(in_module);
3798 // We have to visit module children in deterministic order to avoid
3799 // instabilities in reported imports (#43552).
3800 in_module.for_each_child_stable(|ident, ns, name_binding| {
3801 // avoid imports entirely
3802 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3803 // avoid non-importable candidates as well
3804 if !name_binding.is_importable() { return; }
3806 // collect results based on the filter function
3807 if ident.name == lookup_name && ns == namespace {
3808 if filter_fn(name_binding.def()) {
3810 let mut segms = path_segments.clone();
3811 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3813 span: name_binding.span,
3816 // the entity is accessible in the following cases:
3817 // 1. if it's defined in the same crate, it's always
3818 // accessible (since private entities can be made public)
3819 // 2. if it's defined in another crate, it's accessible
3820 // only if both the module is public and the entity is
3821 // declared as public (due to pruning, we don't explore
3822 // outside crate private modules => no need to check this)
3823 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3824 candidates.push(ImportSuggestion { path: path });
3829 // collect submodules to explore
3830 if let Some(module) = name_binding.module() {
3832 let mut path_segments = path_segments.clone();
3833 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3835 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3836 // add the module to the lookup
3837 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3838 if seen_modules.insert(module.def_id().unwrap()) {
3839 worklist.push((module, path_segments, is_extern));
3849 fn find_module(&mut self,
3851 -> Option<(Module<'a>, ImportSuggestion)>
3853 let mut result = None;
3854 let mut worklist = Vec::new();
3855 let mut seen_modules = FxHashSet();
3856 worklist.push((self.graph_root, Vec::new()));
3858 while let Some((in_module, path_segments)) = worklist.pop() {
3859 // abort if the module is already found
3860 if let Some(_) = result { break; }
3862 self.populate_module_if_necessary(in_module);
3864 in_module.for_each_child_stable(|ident, _, name_binding| {
3865 // abort if the module is already found or if name_binding is private external
3866 if result.is_some() || !name_binding.vis.is_visible_locally() {
3869 if let Some(module) = name_binding.module() {
3871 let mut path_segments = path_segments.clone();
3872 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3873 if module.def() == Some(module_def) {
3875 span: name_binding.span,
3876 segments: path_segments,
3878 result = Some((module, ImportSuggestion { path: path }));
3880 // add the module to the lookup
3881 if seen_modules.insert(module.def_id().unwrap()) {
3882 worklist.push((module, path_segments));
3892 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
3893 if let Def::Enum(..) = enum_def {} else {
3894 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
3897 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
3898 self.populate_module_if_necessary(enum_module);
3900 let mut variants = Vec::new();
3901 enum_module.for_each_child_stable(|ident, _, name_binding| {
3902 if let Def::Variant(..) = name_binding.def() {
3903 let mut segms = enum_import_suggestion.path.segments.clone();
3904 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3905 variants.push(Path {
3906 span: name_binding.span,
3915 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3916 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3917 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3918 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3922 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3924 ast::VisibilityKind::Public => ty::Visibility::Public,
3925 ast::VisibilityKind::Crate(..) => {
3926 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
3928 ast::VisibilityKind::Inherited => {
3929 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3931 ast::VisibilityKind::Restricted { ref path, id, .. } => {
3932 // Visibilities are resolved as global by default, add starting root segment.
3933 let segments = path.make_root().iter().chain(path.segments.iter())
3934 .map(|seg| respan(seg.span, seg.identifier))
3935 .collect::<Vec<_>>();
3936 let def = self.smart_resolve_path_fragment(id, None, &segments, path.span,
3937 PathSource::Visibility).base_def();
3938 if def == Def::Err {
3939 ty::Visibility::Public
3941 let vis = ty::Visibility::Restricted(def.def_id());
3942 if self.is_accessible(vis) {
3945 self.session.span_err(path.span, "visibilities can only be restricted \
3946 to ancestor modules");
3947 ty::Visibility::Public
3954 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3955 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3958 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3959 vis.is_accessible_from(module.normal_ancestor_id, self)
3962 fn report_errors(&mut self, krate: &Crate) {
3963 self.report_shadowing_errors();
3964 self.report_with_use_injections(krate);
3965 self.report_proc_macro_import(krate);
3966 let mut reported_spans = FxHashSet();
3968 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3969 if !reported_spans.insert(span) { continue }
3970 let participle = |binding: &NameBinding| {
3971 if binding.is_import() { "imported" } else { "defined" }
3973 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3974 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3975 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3976 format!("consider adding an explicit import of `{}` to disambiguate", name)
3977 } else if let Def::Macro(..) = b1.def() {
3978 format!("macro-expanded {} do not shadow",
3979 if b1.is_import() { "macro imports" } else { "macros" })
3981 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3982 if b1.is_import() { "imports" } else { "items" })
3985 let id = match b2.kind {
3986 NameBindingKind::Import { directive, .. } => directive.id,
3987 _ => unreachable!(),
3989 let mut span = MultiSpan::from_span(span);
3990 span.push_span_label(b1.span, msg1);
3991 span.push_span_label(b2.span, msg2);
3992 let msg = format!("`{}` is ambiguous", name);
3993 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, &msg);
3996 struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
3997 err.span_note(b1.span, &msg1);
3999 Def::Macro(..) if b2.span == DUMMY_SP =>
4000 err.note(&format!("`{}` is also a builtin macro", name)),
4001 _ => err.span_note(b2.span, &msg2),
4003 err.note(¬e).emit();
4007 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4008 if !reported_spans.insert(span) { continue }
4009 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4013 fn report_with_use_injections(&mut self, krate: &Crate) {
4014 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4015 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4016 if !candidates.is_empty() {
4017 show_candidates(&mut err, span, &candidates, better, found_use);
4023 fn report_shadowing_errors(&mut self) {
4024 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
4025 self.resolve_legacy_scope(scope, ident, true);
4028 let mut reported_errors = FxHashSet();
4029 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4030 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4031 reported_errors.insert((binding.ident, binding.span)) {
4032 let msg = format!("`{}` is already in scope", binding.ident);
4033 self.session.struct_span_err(binding.span, &msg)
4034 .note("macro-expanded `macro_rules!`s may not shadow \
4035 existing macros (see RFC 1560)")
4041 fn report_conflict<'b>(&mut self,
4045 new_binding: &NameBinding<'b>,
4046 old_binding: &NameBinding<'b>) {
4047 // Error on the second of two conflicting names
4048 if old_binding.span.lo() > new_binding.span.lo() {
4049 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4052 let container = match parent.kind {
4053 ModuleKind::Def(Def::Mod(_), _) => "module",
4054 ModuleKind::Def(Def::Trait(_), _) => "trait",
4055 ModuleKind::Block(..) => "block",
4059 let old_noun = match old_binding.is_import() {
4061 false => "definition",
4064 let new_participle = match new_binding.is_import() {
4069 let (name, span) = (ident.name, self.session.codemap().def_span(new_binding.span));
4071 if let Some(s) = self.name_already_seen.get(&name) {
4077 let old_kind = match (ns, old_binding.module()) {
4078 (ValueNS, _) => "value",
4079 (MacroNS, _) => "macro",
4080 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4081 (TypeNS, Some(module)) if module.is_normal() => "module",
4082 (TypeNS, Some(module)) if module.is_trait() => "trait",
4083 (TypeNS, _) => "type",
4086 let namespace = match ns {
4092 let msg = format!("the name `{}` is defined multiple times", name);
4094 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4095 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4096 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4097 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4098 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4100 _ => match (old_binding.is_import(), new_binding.is_import()) {
4101 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4102 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4103 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4107 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4112 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4113 if old_binding.span != DUMMY_SP {
4114 err.span_label(self.session.codemap().def_span(old_binding.span),
4115 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4118 // See https://github.com/rust-lang/rust/issues/32354
4119 if old_binding.is_import() || new_binding.is_import() {
4120 let binding = if new_binding.is_import() && new_binding.span != DUMMY_SP {
4126 let cm = self.session.codemap();
4127 let rename_msg = "You can use `as` to change the binding name of the import";
4129 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4130 binding.is_renamed_extern_crate()) {
4131 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4132 format!("Other{}", name)
4134 format!("other_{}", name)
4137 err.span_suggestion(binding.span,
4139 if snippet.ends_with(';') {
4140 format!("{} as {};",
4141 &snippet[..snippet.len()-1],
4144 format!("{} as {}", snippet, suggested_name)
4147 err.span_label(binding.span, rename_msg);
4152 self.name_already_seen.insert(name, span);
4155 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
4156 let (id, span) = (directive.id, directive.span);
4157 let msg = "`self` no longer imports values";
4158 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
4161 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
4162 if self.proc_macro_enabled { return; }
4165 if attr.path.segments.len() > 1 {
4168 let ident = attr.path.segments[0].identifier;
4169 let result = self.resolve_lexical_macro_path_segment(ident,
4173 if let Ok(binding) = result {
4174 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
4175 attr::mark_known(attr);
4177 let msg = "attribute procedural macros are experimental";
4178 let feature = "proc_macro";
4180 feature_err(&self.session.parse_sess, feature,
4181 attr.span, GateIssue::Language, msg)
4182 .span_label(binding.span(), "procedural macro imported here")
4190 fn is_self_type(path: &[SpannedIdent], namespace: Namespace) -> bool {
4191 namespace == TypeNS && path.len() == 1 && path[0].node.name == keywords::SelfType.name()
4194 fn is_self_value(path: &[SpannedIdent], namespace: Namespace) -> bool {
4195 namespace == ValueNS && path.len() == 1 && path[0].node.name == keywords::SelfValue.name()
4198 fn names_to_string(idents: &[SpannedIdent]) -> String {
4199 let mut result = String::new();
4200 for (i, ident) in idents.iter()
4201 .filter(|i| i.node.name != keywords::CrateRoot.name())
4204 result.push_str("::");
4206 result.push_str(&ident.node.name.as_str());
4211 fn path_names_to_string(path: &Path) -> String {
4212 names_to_string(&path.segments.iter()
4213 .map(|seg| respan(seg.span, seg.identifier))
4214 .collect::<Vec<_>>())
4217 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4218 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4219 let variant_path = &suggestion.path;
4220 let variant_path_string = path_names_to_string(variant_path);
4222 let path_len = suggestion.path.segments.len();
4223 let enum_path = ast::Path {
4224 span: suggestion.path.span,
4225 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4227 let enum_path_string = path_names_to_string(&enum_path);
4229 (suggestion.path.span, variant_path_string, enum_path_string)
4233 /// When an entity with a given name is not available in scope, we search for
4234 /// entities with that name in all crates. This method allows outputting the
4235 /// results of this search in a programmer-friendly way
4236 fn show_candidates(err: &mut DiagnosticBuilder,
4237 // This is `None` if all placement locations are inside expansions
4239 candidates: &[ImportSuggestion],
4243 // we want consistent results across executions, but candidates are produced
4244 // by iterating through a hash map, so make sure they are ordered:
4245 let mut path_strings: Vec<_> =
4246 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4247 path_strings.sort();
4249 let better = if better { "better " } else { "" };
4250 let msg_diff = match path_strings.len() {
4251 1 => " is found in another module, you can import it",
4252 _ => "s are found in other modules, you can import them",
4254 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4256 if let Some(span) = span {
4257 for candidate in &mut path_strings {
4258 // produce an additional newline to separate the new use statement
4259 // from the directly following item.
4260 let additional_newline = if found_use {
4265 *candidate = format!("use {};\n{}", candidate, additional_newline);
4268 err.span_suggestions(span, &msg, path_strings);
4272 for candidate in path_strings {
4274 msg.push_str(&candidate);
4279 /// A somewhat inefficient routine to obtain the name of a module.
4280 fn module_to_string(module: Module) -> Option<String> {
4281 let mut names = Vec::new();
4283 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4284 if let ModuleKind::Def(_, name) = module.kind {
4285 if let Some(parent) = module.parent {
4286 names.push(Ident::with_empty_ctxt(name));
4287 collect_mod(names, parent);
4290 // danger, shouldn't be ident?
4291 names.push(Ident::from_str("<opaque>"));
4292 collect_mod(names, module.parent.unwrap());
4295 collect_mod(&mut names, module);
4297 if names.is_empty() {
4300 Some(names_to_string(&names.into_iter()
4302 .map(|n| dummy_spanned(n))
4303 .collect::<Vec<_>>()))
4306 fn err_path_resolution() -> PathResolution {
4307 PathResolution::new(Def::Err)
4310 #[derive(PartialEq,Copy, Clone)]
4311 pub enum MakeGlobMap {
4316 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }