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 #![crate_name = "rustc_resolve"]
12 #![unstable(feature = "rustc_private", issue = "27812")]
13 #![crate_type = "dylib"]
14 #![crate_type = "rlib"]
15 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
16 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
17 html_root_url = "https://doc.rust-lang.org/nightly/")]
18 #![cfg_attr(not(stage0), deny(warnings))]
20 #![feature(associated_consts)]
21 #![feature(borrow_state)]
22 #![feature(rustc_diagnostic_macros)]
23 #![feature(rustc_private)]
24 #![feature(staged_api)]
30 extern crate syntax_pos;
31 extern crate rustc_errors as errors;
36 use self::Namespace::*;
37 use self::ResolveResult::*;
38 use self::FallbackSuggestion::*;
39 use self::TypeParameters::*;
41 use self::UseLexicalScopeFlag::*;
42 use self::ModulePrefixResult::*;
43 use self::ParentLink::*;
45 use rustc::hir::map::Definitions;
46 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
47 use rustc::session::Session;
49 use rustc::hir::def::*;
50 use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
52 use rustc::ty::subst::{ParamSpace, FnSpace, TypeSpace};
53 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
54 use rustc::util::nodemap::{NodeMap, NodeSet, FnvHashMap, FnvHashSet};
56 use syntax::ext::mtwt;
57 use syntax::ast::{self, FloatTy};
58 use syntax::ast::{CRATE_NODE_ID, Name, NodeId, CrateNum, IntTy, UintTy};
59 use syntax::parse::token::{self, keywords};
60 use syntax::util::lev_distance::find_best_match_for_name;
62 use syntax::visit::{self, FnKind, Visitor};
63 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
64 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
65 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
66 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
67 use syntax::ast::{PathSegment, PathParameters, QSelf, TraitItemKind, TraitRef, Ty, TyKind};
70 use errors::DiagnosticBuilder;
72 use std::collections::{HashMap, HashSet};
73 use std::cell::{Cell, RefCell};
75 use std::mem::replace;
77 use resolve_imports::{ImportDirective, NameResolution};
79 // NB: This module needs to be declared first so diagnostics are
80 // registered before they are used.
84 mod build_reduced_graph;
89 Function(token::InternedString),
93 /// Candidates for a name resolution failure
94 struct SuggestedCandidates {
96 candidates: Vec<Path>,
99 enum ResolutionError<'a> {
100 /// error E0401: can't use type parameters from outer function
101 TypeParametersFromOuterFunction,
102 /// error E0402: cannot use an outer type parameter in this context
103 OuterTypeParameterContext,
104 /// error E0403: the name is already used for a type parameter in this type parameter list
105 NameAlreadyUsedInTypeParameterList(Name),
106 /// error E0404: is not a trait
107 IsNotATrait(&'a str),
108 /// error E0405: use of undeclared trait name
109 UndeclaredTraitName(&'a str, SuggestedCandidates),
110 /// error E0407: method is not a member of trait
111 MethodNotMemberOfTrait(Name, &'a str),
112 /// error E0437: type is not a member of trait
113 TypeNotMemberOfTrait(Name, &'a str),
114 /// error E0438: const is not a member of trait
115 ConstNotMemberOfTrait(Name, &'a str),
116 /// error E0408: variable `{}` from pattern #{} is not bound in pattern #{}
117 VariableNotBoundInPattern(Name, usize, usize),
118 /// error E0409: variable is bound with different mode in pattern #{} than in pattern #1
119 VariableBoundWithDifferentMode(Name, usize),
120 /// error E0411: use of `Self` outside of an impl or trait
121 SelfUsedOutsideImplOrTrait,
122 /// error E0412: use of undeclared
123 UseOfUndeclared(&'a str, &'a str, SuggestedCandidates),
124 /// error E0415: identifier is bound more than once in this parameter list
125 IdentifierBoundMoreThanOnceInParameterList(&'a str),
126 /// error E0416: identifier is bound more than once in the same pattern
127 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
128 /// error E0422: does not name a struct
129 DoesNotNameAStruct(&'a str),
130 /// error E0423: is a struct variant name, but this expression uses it like a function name
131 StructVariantUsedAsFunction(&'a str),
132 /// error E0424: `self` is not available in a static method
133 SelfNotAvailableInStaticMethod,
134 /// error E0425: unresolved name
138 context: UnresolvedNameContext<'a>,
139 is_static_method: bool,
143 /// error E0426: use of undeclared label
144 UndeclaredLabel(&'a str),
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<(&'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, &'a str, Name),
161 /// error E0531: unresolved pattern path kind `name`
162 PatPathUnresolved(&'a str, &'a Path),
163 /// error E0532: expected pattern path kind, found another pattern path kind
164 PatPathUnexpected(&'a str, &'a str, &'a Path),
167 /// Context of where `ResolutionError::UnresolvedName` arose.
168 #[derive(Clone, PartialEq, Eq, Debug)]
169 enum UnresolvedNameContext<'a> {
170 /// `PathIsMod(parent)` indicates that a given path, used in
171 /// expression context, actually resolved to a module rather than
172 /// a value. The optional expression attached to the variant is the
173 /// the parent of the erroneous path expression.
174 PathIsMod(Option<&'a Expr>),
176 /// `Other` means we have no extra information about the context
177 /// of the unresolved name error. (Maybe we could eliminate all
178 /// such cases; but for now, this is an information-free default.)
182 fn resolve_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
183 span: syntax_pos::Span,
184 resolution_error: ResolutionError<'c>) {
185 resolve_struct_error(resolver, span, resolution_error).emit();
188 fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
189 span: syntax_pos::Span,
190 resolution_error: ResolutionError<'c>)
191 -> DiagnosticBuilder<'a> {
192 if !resolver.emit_errors {
193 return resolver.session.diagnostic().struct_dummy();
196 match resolution_error {
197 ResolutionError::TypeParametersFromOuterFunction => {
198 let mut err = struct_span_err!(resolver.session,
201 "can't use type parameters from outer function; \
202 try using a local type parameter instead");
203 err.span_label(span, &format!("use of type variable from outer function"));
206 ResolutionError::OuterTypeParameterContext => {
207 struct_span_err!(resolver.session,
210 "cannot use an outer type parameter in this context")
212 ResolutionError::NameAlreadyUsedInTypeParameterList(name) => {
213 struct_span_err!(resolver.session,
216 "the name `{}` is already used for a type parameter in this type \
220 ResolutionError::IsNotATrait(name) => {
221 struct_span_err!(resolver.session, span, E0404, "`{}` is not a trait", name)
223 ResolutionError::UndeclaredTraitName(name, candidates) => {
224 let mut err = struct_span_err!(resolver.session,
227 "trait `{}` is not in scope",
229 show_candidates(&mut err, &candidates);
230 err.span_label(span, &format!("`{}` is not in scope", name));
233 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
234 struct_span_err!(resolver.session,
237 "method `{}` is not a member of trait `{}`",
241 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
242 struct_span_err!(resolver.session,
245 "type `{}` is not a member of trait `{}`",
249 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
250 struct_span_err!(resolver.session,
253 "const `{}` is not a member of trait `{}`",
257 ResolutionError::VariableNotBoundInPattern(variable_name, from, to) => {
258 struct_span_err!(resolver.session,
261 "variable `{}` from pattern #{} is not bound in pattern #{}",
266 ResolutionError::VariableBoundWithDifferentMode(variable_name, pattern_number) => {
267 struct_span_err!(resolver.session,
270 "variable `{}` is bound with different mode in pattern #{} than in \
275 ResolutionError::SelfUsedOutsideImplOrTrait => {
276 let mut err = struct_span_err!(resolver.session,
279 "use of `Self` outside of an impl or trait");
280 err.span_label(span, &format!("used outside of impl or trait"));
283 ResolutionError::UseOfUndeclared(kind, name, candidates) => {
284 let mut err = struct_span_err!(resolver.session,
287 "{} `{}` is undefined or not in scope",
290 show_candidates(&mut err, &candidates);
291 err.span_label(span, &format!("undefined or not in scope"));
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, &format!("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, &format!("used in a pattern more than once"));
312 ResolutionError::DoesNotNameAStruct(name) => {
313 struct_span_err!(resolver.session,
316 "`{}` does not name a structure",
319 ResolutionError::StructVariantUsedAsFunction(path_name) => {
320 struct_span_err!(resolver.session,
323 "`{}` is the name of a struct or struct variant, but this expression \
324 uses it like a function name",
327 ResolutionError::SelfNotAvailableInStaticMethod => {
328 struct_span_err!(resolver.session,
331 "`self` is not available in a static method. Maybe a `self` \
332 argument is missing?")
334 ResolutionError::UnresolvedName { path, message: msg, context, is_static_method,
336 let mut err = struct_span_err!(resolver.session,
339 "unresolved name `{}`{}",
343 UnresolvedNameContext::Other => {
344 if msg.is_empty() && is_static_method && is_field {
345 err.help("this is an associated function, you don't have access to \
346 this type's fields or methods");
349 UnresolvedNameContext::PathIsMod(parent) => {
350 err.help(&match parent.map(|parent| &parent.node) {
351 Some(&ExprKind::Field(_, ident)) => {
352 format!("to reference an item from the `{module}` module, \
353 use `{module}::{ident}`",
357 Some(&ExprKind::MethodCall(ident, _, _)) => {
358 format!("to call a function from the `{module}` module, \
359 use `{module}::{ident}(..)`",
364 format!("{def} `{module}` cannot be used as an expression",
365 def = def.kind_name(),
373 ResolutionError::UndeclaredLabel(name) => {
374 struct_span_err!(resolver.session,
377 "use of undeclared label `{}`",
380 ResolutionError::SelfImportsOnlyAllowedWithin => {
381 struct_span_err!(resolver.session,
385 "`self` imports are only allowed within a { } list")
387 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
388 struct_span_err!(resolver.session,
391 "`self` import can only appear once in the list")
393 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
394 struct_span_err!(resolver.session,
397 "`self` import can only appear in an import list with a \
400 ResolutionError::UnresolvedImport(name) => {
401 let msg = match name {
402 Some((n, p)) => format!("unresolved import `{}`{}", n, p),
403 None => "unresolved import".to_owned(),
405 struct_span_err!(resolver.session, span, E0432, "{}", msg)
407 ResolutionError::FailedToResolve(msg) => {
408 struct_span_err!(resolver.session, span, E0433, "failed to resolve. {}", msg)
410 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
411 struct_span_err!(resolver.session,
415 "can't capture dynamic environment in a fn item; use the || { ... } \
416 closure form instead")
418 ResolutionError::AttemptToUseNonConstantValueInConstant => {
419 struct_span_err!(resolver.session,
422 "attempt to use a non-constant value in a constant")
424 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, shadows_what, name) => {
425 let mut err = struct_span_err!(resolver.session,
428 "{}s cannot shadow {}s", what_binding, shadows_what);
429 err.span_label(span, &format!("cannot be named the same as a {}", shadows_what));
430 if let Success(binding) = resolver.current_module.resolve_name(name, ValueNS, true) {
431 let participle = if binding.is_import() { "imported" } else { "defined" };
432 err.span_label(binding.span, &format!("a {} `{}` is {} here",
433 shadows_what, name, participle));
437 ResolutionError::PatPathUnresolved(expected_what, path) => {
438 struct_span_err!(resolver.session,
441 "unresolved {} `{}`",
443 path.segments.last().unwrap().identifier)
445 ResolutionError::PatPathUnexpected(expected_what, found_what, path) => {
446 struct_span_err!(resolver.session,
449 "expected {}, found {} `{}`",
452 path.segments.last().unwrap().identifier)
457 #[derive(Copy, Clone)]
460 binding_mode: BindingMode,
463 // Map from the name in a pattern to its binding mode.
464 type BindingMap = HashMap<Name, BindingInfo>;
466 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
477 fn is_refutable(self) -> bool {
479 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
480 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
483 fn descr(self) -> &'static str {
485 PatternSource::Match => "match binding",
486 PatternSource::IfLet => "if let binding",
487 PatternSource::WhileLet => "while let binding",
488 PatternSource::Let => "let binding",
489 PatternSource::For => "for binding",
490 PatternSource::FnParam => "function parameter",
495 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
501 impl<'a> Visitor for Resolver<'a> {
502 fn visit_item(&mut self, item: &Item) {
503 self.resolve_item(item);
505 fn visit_arm(&mut self, arm: &Arm) {
506 self.resolve_arm(arm);
508 fn visit_block(&mut self, block: &Block) {
509 self.resolve_block(block);
511 fn visit_expr(&mut self, expr: &Expr) {
512 self.resolve_expr(expr, None);
514 fn visit_local(&mut self, local: &Local) {
515 self.resolve_local(local);
517 fn visit_ty(&mut self, ty: &Ty) {
518 self.resolve_type(ty);
520 fn visit_poly_trait_ref(&mut self, tref: &ast::PolyTraitRef, m: &ast::TraitBoundModifier) {
521 match self.resolve_trait_reference(tref.trait_ref.ref_id, &tref.trait_ref.path, 0) {
522 Ok(def) => self.record_def(tref.trait_ref.ref_id, def),
524 // error already reported
525 self.record_def(tref.trait_ref.ref_id, err_path_resolution())
528 visit::walk_poly_trait_ref(self, tref, m);
530 fn visit_variant(&mut self,
531 variant: &ast::Variant,
533 item_id: ast::NodeId) {
534 if let Some(ref dis_expr) = variant.node.disr_expr {
535 // resolve the discriminator expr as a constant
536 self.with_constant_rib(|this| {
537 this.visit_expr(dis_expr);
541 // `visit::walk_variant` without the discriminant expression.
542 self.visit_variant_data(&variant.node.data,
548 fn visit_foreign_item(&mut self, foreign_item: &ForeignItem) {
549 let type_parameters = match foreign_item.node {
550 ForeignItemKind::Fn(_, ref generics) => {
551 HasTypeParameters(generics, FnSpace, ItemRibKind)
553 ForeignItemKind::Static(..) => NoTypeParameters,
555 self.with_type_parameter_rib(type_parameters, |this| {
556 visit::walk_foreign_item(this, foreign_item);
559 fn visit_fn(&mut self,
560 function_kind: FnKind,
561 declaration: &FnDecl,
565 let rib_kind = match function_kind {
566 FnKind::ItemFn(_, generics, _, _, _, _) => {
567 self.visit_generics(generics);
570 FnKind::Method(_, sig, _) => {
571 self.visit_generics(&sig.generics);
572 MethodRibKind(!sig.decl.has_self())
574 FnKind::Closure => ClosureRibKind(node_id),
576 self.resolve_function(rib_kind, declaration, block);
580 pub type ErrorMessage = Option<(Span, String)>;
582 #[derive(Clone, PartialEq, Eq)]
583 pub enum ResolveResult<T> {
584 Failed(ErrorMessage), // Failed to resolve the name, optional helpful error message.
585 Indeterminate, // Couldn't determine due to unresolved globs.
586 Success(T), // Successfully resolved the import.
589 impl<T> ResolveResult<T> {
590 fn and_then<U, F: FnOnce(T) -> ResolveResult<U>>(self, f: F) -> ResolveResult<U> {
592 Failed(msg) => Failed(msg),
593 Indeterminate => Indeterminate,
598 fn success(self) -> Option<T> {
600 Success(t) => Some(t),
606 enum FallbackSuggestion {
613 #[derive(Copy, Clone)]
614 enum TypeParameters<'a, 'b> {
616 HasTypeParameters(// Type parameters.
619 // Identifies the things that these parameters
620 // were declared on (type, fn, etc)
623 // The kind of the rib used for type parameters.
627 // The rib kind controls the translation of local
628 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
629 #[derive(Copy, Clone, Debug)]
631 // No translation needs to be applied.
634 // We passed through a closure scope at the given node ID.
635 // Translate upvars as appropriate.
636 ClosureRibKind(NodeId /* func id */),
638 // We passed through an impl or trait and are now in one of its
639 // methods. Allow references to ty params that impl or trait
640 // binds. Disallow any other upvars (including other ty params that are
643 // The boolean value represents the fact that this method is static or not.
646 // We passed through an item scope. Disallow upvars.
649 // We're in a constant item. Can't refer to dynamic stuff.
652 // We passed through a module.
653 ModuleRibKind(Module<'a>),
656 #[derive(Copy, Clone)]
657 enum UseLexicalScopeFlag {
662 enum ModulePrefixResult<'a> {
664 PrefixFound(Module<'a>, usize),
670 bindings: HashMap<Name, Def>,
675 fn new(kind: RibKind<'a>) -> Rib<'a> {
677 bindings: HashMap::new(),
683 /// A definition along with the index of the rib it was found on
685 ribs: Option<(Namespace, usize)>,
690 fn from_def(def: Def) -> Self {
698 enum LexicalScopeBinding<'a> {
699 Item(&'a NameBinding<'a>),
703 impl<'a> LexicalScopeBinding<'a> {
704 fn local_def(self) -> LocalDef {
706 LexicalScopeBinding::LocalDef(local_def) => local_def,
707 LexicalScopeBinding::Item(binding) => LocalDef::from_def(binding.def().unwrap()),
711 fn module(self) -> Option<Module<'a>> {
713 LexicalScopeBinding::Item(binding) => binding.module(),
719 /// The link from a module up to its nearest parent node.
720 #[derive(Clone,Debug)]
721 enum ParentLink<'a> {
723 ModuleParentLink(Module<'a>, Name),
724 BlockParentLink(Module<'a>, NodeId),
727 /// One node in the tree of modules.
728 pub struct ModuleS<'a> {
729 parent_link: ParentLink<'a>,
732 // If the module is an extern crate, `def` is root of the external crate and `extern_crate_id`
733 // is the NodeId of the local `extern crate` item (otherwise, `extern_crate_id` is None).
734 extern_crate_id: Option<NodeId>,
736 resolutions: RefCell<HashMap<(Name, Namespace), &'a RefCell<NameResolution<'a>>>>,
737 unresolved_imports: RefCell<Vec<&'a ImportDirective<'a>>>,
739 no_implicit_prelude: Cell<bool>,
741 glob_importers: RefCell<Vec<(Module<'a>, &'a ImportDirective<'a>)>>,
742 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
744 // Used to memoize the traits in this module for faster searches through all traits in scope.
745 traits: RefCell<Option<Box<[(Name, &'a NameBinding<'a>)]>>>,
747 // Whether this module is populated. If not populated, any attempt to
748 // access the children must be preceded with a
749 // `populate_module_if_necessary` call.
750 populated: Cell<bool>,
752 arenas: &'a ResolverArenas<'a>,
755 pub type Module<'a> = &'a ModuleS<'a>;
757 impl<'a> ModuleS<'a> {
758 fn new(parent_link: ParentLink<'a>,
761 arenas: &'a ResolverArenas<'a>) -> Self {
763 parent_link: parent_link,
765 extern_crate_id: None,
766 resolutions: RefCell::new(HashMap::new()),
767 unresolved_imports: RefCell::new(Vec::new()),
768 no_implicit_prelude: Cell::new(false),
769 glob_importers: RefCell::new(Vec::new()),
770 globs: RefCell::new((Vec::new())),
771 traits: RefCell::new(None),
772 populated: Cell::new(!external),
777 fn for_each_child<F: FnMut(Name, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
778 for (&(name, ns), name_resolution) in self.resolutions.borrow().iter() {
779 name_resolution.borrow().binding.map(|binding| f(name, ns, binding));
783 fn def_id(&self) -> Option<DefId> {
784 self.def.as_ref().map(Def::def_id)
787 // `self` resolves to the first module ancestor that `is_normal`.
788 fn is_normal(&self) -> bool {
790 Some(Def::Mod(_)) => true,
795 fn is_trait(&self) -> bool {
797 Some(Def::Trait(_)) => true,
803 impl<'a> fmt::Debug for ModuleS<'a> {
804 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
805 write!(f, "{:?}", self.def)
809 // Records a possibly-private value, type, or module definition.
810 #[derive(Clone, Debug)]
811 pub struct NameBinding<'a> {
812 kind: NameBindingKind<'a>,
817 #[derive(Clone, Debug)]
818 enum NameBindingKind<'a> {
822 binding: &'a NameBinding<'a>,
823 directive: &'a ImportDirective<'a>,
824 // Some(error) if using this imported name causes the import to be a privacy error
825 privacy_error: Option<Box<PrivacyError<'a>>>,
829 #[derive(Clone, Debug)]
830 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
832 impl<'a> NameBinding<'a> {
833 fn module(&self) -> Option<Module<'a>> {
835 NameBindingKind::Module(module) => Some(module),
836 NameBindingKind::Def(_) => None,
837 NameBindingKind::Import { binding, .. } => binding.module(),
841 fn def(&self) -> Option<Def> {
843 NameBindingKind::Def(def) => Some(def),
844 NameBindingKind::Module(module) => module.def,
845 NameBindingKind::Import { binding, .. } => binding.def(),
849 fn is_pseudo_public(&self) -> bool {
850 self.pseudo_vis() == ty::Visibility::Public
853 // We sometimes need to treat variants as `pub` for backwards compatibility
854 fn pseudo_vis(&self) -> ty::Visibility {
855 if self.is_variant() { ty::Visibility::Public } else { self.vis }
858 fn is_variant(&self) -> bool {
860 NameBindingKind::Def(Def::Variant(..)) => true,
865 fn is_extern_crate(&self) -> bool {
866 self.module().and_then(|module| module.extern_crate_id).is_some()
869 fn is_import(&self) -> bool {
871 NameBindingKind::Import { .. } => true,
876 fn is_glob_import(&self) -> bool {
878 NameBindingKind::Import { directive, .. } => directive.is_glob(),
883 fn is_importable(&self) -> bool {
884 match self.def().unwrap() {
885 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
891 /// Interns the names of the primitive types.
892 struct PrimitiveTypeTable {
893 primitive_types: HashMap<Name, PrimTy>,
896 impl PrimitiveTypeTable {
897 fn new() -> PrimitiveTypeTable {
898 let mut table = PrimitiveTypeTable { primitive_types: HashMap::new() };
900 table.intern("bool", TyBool);
901 table.intern("char", TyChar);
902 table.intern("f32", TyFloat(FloatTy::F32));
903 table.intern("f64", TyFloat(FloatTy::F64));
904 table.intern("isize", TyInt(IntTy::Is));
905 table.intern("i8", TyInt(IntTy::I8));
906 table.intern("i16", TyInt(IntTy::I16));
907 table.intern("i32", TyInt(IntTy::I32));
908 table.intern("i64", TyInt(IntTy::I64));
909 table.intern("str", TyStr);
910 table.intern("usize", TyUint(UintTy::Us));
911 table.intern("u8", TyUint(UintTy::U8));
912 table.intern("u16", TyUint(UintTy::U16));
913 table.intern("u32", TyUint(UintTy::U32));
914 table.intern("u64", TyUint(UintTy::U64));
919 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
920 self.primitive_types.insert(token::intern(string), primitive_type);
924 /// The main resolver class.
925 pub struct Resolver<'a> {
926 session: &'a Session,
928 pub definitions: Definitions,
930 graph_root: Module<'a>,
932 prelude: Option<Module<'a>>,
934 trait_item_map: FnvHashMap<(Name, DefId), bool /* is static method? */>,
936 structs: FnvHashMap<DefId, Vec<Name>>,
938 // The number of imports that are currently unresolved.
939 unresolved_imports: usize,
941 // The module that represents the current item scope.
942 current_module: Module<'a>,
944 // The current set of local scopes, for values.
945 // FIXME #4948: Reuse ribs to avoid allocation.
946 value_ribs: Vec<Rib<'a>>,
948 // The current set of local scopes, for types.
949 type_ribs: Vec<Rib<'a>>,
951 // The current set of local scopes, for labels.
952 label_ribs: Vec<Rib<'a>>,
954 // The trait that the current context can refer to.
955 current_trait_ref: Option<(DefId, TraitRef)>,
957 // The current self type if inside an impl (used for better errors).
958 current_self_type: Option<Ty>,
960 // The idents for the primitive types.
961 primitive_type_table: PrimitiveTypeTable,
964 pub freevars: FreevarMap,
965 freevars_seen: NodeMap<NodeMap<usize>>,
966 pub export_map: ExportMap,
967 pub trait_map: TraitMap,
969 // A map from nodes to modules, both normal (`mod`) modules and anonymous modules.
970 // Anonymous modules are pseudo-modules that are implicitly created around items
971 // contained within blocks.
973 // For example, if we have this:
981 // There will be an anonymous module created around `g` with the ID of the
982 // entry block for `f`.
983 module_map: NodeMap<Module<'a>>,
985 // Whether or not to print error messages. Can be set to true
986 // when getting additional info for error message suggestions,
987 // so as to avoid printing duplicate errors
990 pub make_glob_map: bool,
991 // Maps imports to the names of items actually imported (this actually maps
992 // all imports, but only glob imports are actually interesting).
993 pub glob_map: GlobMap,
995 used_imports: HashSet<(NodeId, Namespace)>,
996 used_crates: HashSet<CrateNum>,
997 pub maybe_unused_trait_imports: NodeSet,
999 privacy_errors: Vec<PrivacyError<'a>>,
1001 arenas: &'a ResolverArenas<'a>,
1004 pub struct ResolverArenas<'a> {
1005 modules: arena::TypedArena<ModuleS<'a>>,
1006 local_modules: RefCell<Vec<Module<'a>>>,
1007 name_bindings: arena::TypedArena<NameBinding<'a>>,
1008 import_directives: arena::TypedArena<ImportDirective<'a>>,
1009 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1012 impl<'a> ResolverArenas<'a> {
1013 fn alloc_module(&'a self, module: ModuleS<'a>) -> Module<'a> {
1014 let module = self.modules.alloc(module);
1015 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1016 self.local_modules.borrow_mut().push(module);
1020 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1021 self.local_modules.borrow()
1023 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1024 self.name_bindings.alloc(name_binding)
1026 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1027 -> &'a ImportDirective {
1028 self.import_directives.alloc(import_directive)
1030 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1031 self.name_resolutions.alloc(Default::default())
1035 impl<'a> ty::NodeIdTree for Resolver<'a> {
1036 fn is_descendant_of(&self, node: NodeId, ancestor: NodeId) -> bool {
1037 let ancestor = self.definitions.local_def_id(ancestor);
1038 let mut module = *self.module_map.get(&node).unwrap();
1039 while module.def_id() != Some(ancestor) {
1040 let module_parent = match self.get_nearest_normal_module_parent(module) {
1041 Some(parent) => parent,
1042 None => return false,
1044 module = module_parent;
1050 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1051 fn resolve_generated_global_path(&mut self, path: &hir::Path, is_value: bool) -> Def {
1052 let namespace = if is_value { ValueNS } else { TypeNS };
1053 match self.resolve_crate_relative_path(path.span, &path.segments, namespace) {
1054 Ok(binding) => binding.def().unwrap(),
1055 Err(true) => Def::Err,
1057 let path_name = &format!("{}", path);
1059 ResolutionError::UnresolvedName {
1062 context: UnresolvedNameContext::Other,
1063 is_static_method: false,
1067 resolve_error(self, path.span, error);
1073 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1074 self.def_map.get(&id).cloned()
1077 fn record_resolution(&mut self, id: NodeId, def: Def) {
1078 self.def_map.insert(id, PathResolution::new(def));
1081 fn definitions(&mut self) -> Option<&mut Definitions> {
1082 Some(&mut self.definitions)
1087 fn name(&self) -> Name;
1090 impl Named for ast::PathSegment {
1091 fn name(&self) -> Name {
1092 self.identifier.name
1096 impl Named for hir::PathSegment {
1097 fn name(&self) -> Name {
1102 impl<'a> Resolver<'a> {
1103 pub fn new(session: &'a Session, make_glob_map: MakeGlobMap, arenas: &'a ResolverArenas<'a>)
1105 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1107 ModuleS::new(NoParentLink, Some(Def::Mod(root_def_id)), false, arenas);
1108 let graph_root = arenas.alloc_module(graph_root);
1109 let mut module_map = NodeMap();
1110 module_map.insert(CRATE_NODE_ID, graph_root);
1115 definitions: Definitions::new(),
1117 // The outermost module has def ID 0; this is not reflected in the
1119 graph_root: graph_root,
1122 trait_item_map: FnvHashMap(),
1123 structs: FnvHashMap(),
1125 unresolved_imports: 0,
1127 current_module: graph_root,
1128 value_ribs: vec![Rib::new(ModuleRibKind(graph_root))],
1129 type_ribs: vec![Rib::new(ModuleRibKind(graph_root))],
1130 label_ribs: Vec::new(),
1132 current_trait_ref: None,
1133 current_self_type: None,
1135 primitive_type_table: PrimitiveTypeTable::new(),
1138 freevars: NodeMap(),
1139 freevars_seen: NodeMap(),
1140 export_map: NodeMap(),
1141 trait_map: NodeMap(),
1142 module_map: module_map,
1145 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1146 glob_map: NodeMap(),
1148 used_imports: HashSet::new(),
1149 used_crates: HashSet::new(),
1150 maybe_unused_trait_imports: NodeSet(),
1152 privacy_errors: Vec::new(),
1158 pub fn arenas() -> ResolverArenas<'a> {
1160 modules: arena::TypedArena::new(),
1161 local_modules: RefCell::new(Vec::new()),
1162 name_bindings: arena::TypedArena::new(),
1163 import_directives: arena::TypedArena::new(),
1164 name_resolutions: arena::TypedArena::new(),
1168 /// Entry point to crate resolution.
1169 pub fn resolve_crate(&mut self, krate: &Crate) {
1170 // Currently, we ignore the name resolution data structures for
1171 // the purposes of dependency tracking. Instead we will run name
1172 // resolution and include its output in the hash of each item,
1173 // much like we do for macro expansion. In other words, the hash
1174 // reflects not just its contents but the results of name
1175 // resolution on those contents. Hopefully we'll push this back at
1177 let _ignore = self.session.dep_graph.in_ignore();
1179 self.build_reduced_graph(krate);
1180 resolve_imports::resolve_imports(self);
1182 self.current_module = self.graph_root;
1183 visit::walk_crate(self, krate);
1185 check_unused::check_crate(self, krate);
1186 self.report_privacy_errors();
1189 fn new_module(&self, parent_link: ParentLink<'a>, def: Option<Def>, external: bool)
1191 self.arenas.alloc_module(ModuleS::new(parent_link, def, external, self.arenas))
1194 fn new_extern_crate_module(&self, parent_link: ParentLink<'a>, def: Def, local_node_id: NodeId)
1196 let mut module = ModuleS::new(parent_link, Some(def), false, self.arenas);
1197 module.extern_crate_id = Some(local_node_id);
1198 self.arenas.modules.alloc(module)
1201 fn get_ribs<'b>(&'b mut self, ns: Namespace) -> &'b mut Vec<Rib<'a>> {
1202 match ns { ValueNS => &mut self.value_ribs, TypeNS => &mut self.type_ribs }
1206 fn record_use(&mut self, name: Name, binding: &'a NameBinding<'a>) {
1207 // track extern crates for unused_extern_crate lint
1208 if let Some(DefId { krate, .. }) = binding.module().and_then(ModuleS::def_id) {
1209 self.used_crates.insert(krate);
1212 let (directive, privacy_error) = match binding.kind {
1213 NameBindingKind::Import { directive, ref privacy_error, .. } =>
1214 (directive, privacy_error),
1218 if let Some(error) = privacy_error.as_ref() {
1219 self.privacy_errors.push((**error).clone());
1222 if !self.make_glob_map {
1225 if self.glob_map.contains_key(&directive.id) {
1226 self.glob_map.get_mut(&directive.id).unwrap().insert(name);
1230 let mut new_set = FnvHashSet();
1231 new_set.insert(name);
1232 self.glob_map.insert(directive.id, new_set);
1235 /// Resolves the given module path from the given root `module_`.
1236 fn resolve_module_path_from_root(&mut self,
1237 module_: Module<'a>,
1238 module_path: &[Name],
1241 -> ResolveResult<Module<'a>> {
1242 fn search_parent_externals(needle: Name, module: Module) -> Option<Module> {
1243 match module.resolve_name(needle, TypeNS, false) {
1244 Success(binding) if binding.is_extern_crate() => Some(module),
1245 _ => match module.parent_link {
1246 ModuleParentLink(ref parent, _) => {
1247 search_parent_externals(needle, parent)
1254 let mut search_module = module_;
1255 let mut index = index;
1256 let module_path_len = module_path.len();
1258 // Resolve the module part of the path. This does not involve looking
1259 // upward though scope chains; we simply resolve names directly in
1260 // modules as we go.
1261 while index < module_path_len {
1262 let name = module_path[index];
1263 match self.resolve_name_in_module(search_module, name, TypeNS, false, true) {
1265 let segment_name = name.as_str();
1266 let module_name = module_to_string(search_module);
1267 let msg = if "???" == &module_name {
1268 match search_parent_externals(name, &self.current_module) {
1270 let path_str = names_to_string(module_path);
1271 let target_mod_str = module_to_string(&module);
1272 let current_mod_str = module_to_string(&self.current_module);
1274 let prefix = if target_mod_str == current_mod_str {
1275 "self::".to_string()
1277 format!("{}::", target_mod_str)
1280 format!("Did you mean `{}{}`?", prefix, path_str)
1282 None => format!("Maybe a missing `extern crate {}`?", segment_name),
1285 format!("Could not find `{}` in `{}`", segment_name, module_name)
1288 return Failed(Some((span, msg)));
1290 Failed(err) => return Failed(err),
1292 debug!("(resolving module path for import) module resolution is \
1295 return Indeterminate;
1297 Success(binding) => {
1298 // Check to see whether there are type bindings, and, if
1299 // so, whether there is a module within.
1300 if let Some(module_def) = binding.module() {
1301 self.check_privacy(name, binding, span);
1302 search_module = module_def;
1304 let msg = format!("Not a module `{}`", name);
1305 return Failed(Some((span, msg)));
1313 return Success(search_module);
1316 /// Attempts to resolve the module part of an import directive or path
1317 /// rooted at the given module.
1318 fn resolve_module_path(&mut self,
1319 module_path: &[Name],
1320 use_lexical_scope: UseLexicalScopeFlag,
1322 -> ResolveResult<Module<'a>> {
1323 if module_path.len() == 0 {
1324 return Success(self.graph_root) // Use the crate root
1327 debug!("(resolving module path for import) processing `{}` rooted at `{}`",
1328 names_to_string(module_path),
1329 module_to_string(self.current_module));
1331 // Resolve the module prefix, if any.
1332 let module_prefix_result = self.resolve_module_prefix(module_path, span);
1336 match module_prefix_result {
1337 Failed(err) => return Failed(err),
1339 debug!("(resolving module path for import) indeterminate; bailing");
1340 return Indeterminate;
1342 Success(NoPrefixFound) => {
1343 // There was no prefix, so we're considering the first element
1344 // of the path. How we handle this depends on whether we were
1345 // instructed to use lexical scope or not.
1346 match use_lexical_scope {
1347 DontUseLexicalScope => {
1348 // This is a crate-relative path. We will start the
1349 // resolution process at index zero.
1350 search_module = self.graph_root;
1353 UseLexicalScope => {
1354 // This is not a crate-relative path. We resolve the
1355 // first component of the path in the current lexical
1356 // scope and then proceed to resolve below that.
1357 let ident = ast::Ident::with_empty_ctxt(module_path[0]);
1358 match self.resolve_ident_in_lexical_scope(ident, TypeNS, true)
1359 .and_then(LexicalScopeBinding::module) {
1360 None => return Failed(None),
1361 Some(containing_module) => {
1362 search_module = containing_module;
1369 Success(PrefixFound(ref containing_module, index)) => {
1370 search_module = containing_module;
1371 start_index = index;
1375 self.resolve_module_path_from_root(search_module,
1381 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1382 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1383 /// `ident` in the first scope that defines it (or None if no scopes define it).
1385 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1386 /// the items are defined in the block. For example,
1389 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1392 /// g(); // This resolves to the local variable `g` since it shadows the item.
1396 /// Invariant: This must only be called during main resolution, not during
1397 /// import resolution.
1398 fn resolve_ident_in_lexical_scope(&mut self,
1402 -> Option<LexicalScopeBinding<'a>> {
1403 let name = match ns { ValueNS => mtwt::resolve(ident), TypeNS => ident.name };
1405 // Walk backwards up the ribs in scope.
1406 for i in (0 .. self.get_ribs(ns).len()).rev() {
1407 if let Some(def) = self.get_ribs(ns)[i].bindings.get(&name).cloned() {
1408 // The ident resolves to a type parameter or local variable.
1409 return Some(LexicalScopeBinding::LocalDef(LocalDef {
1410 ribs: Some((ns, i)),
1415 if let ModuleRibKind(module) = self.get_ribs(ns)[i].kind {
1416 let name = ident.name;
1417 let item = self.resolve_name_in_module(module, name, ns, true, record_used);
1418 if let Success(binding) = item {
1419 // The ident resolves to an item.
1420 return Some(LexicalScopeBinding::Item(binding));
1423 // We can only see through anonymous modules
1424 if module.def.is_some() {
1425 return match self.prelude {
1426 Some(prelude) if !module.no_implicit_prelude.get() => {
1427 prelude.resolve_name(name, ns, false).success()
1428 .map(LexicalScopeBinding::Item)
1439 /// Returns the nearest normal module parent of the given module.
1440 fn get_nearest_normal_module_parent(&self, module_: Module<'a>) -> Option<Module<'a>> {
1441 let mut module_ = module_;
1443 match module_.parent_link {
1444 NoParentLink => return None,
1445 ModuleParentLink(new_module, _) |
1446 BlockParentLink(new_module, _) => {
1447 let new_module = new_module;
1448 if new_module.is_normal() {
1449 return Some(new_module);
1451 module_ = new_module;
1457 /// Returns the nearest normal module parent of the given module, or the
1458 /// module itself if it is a normal module.
1459 fn get_nearest_normal_module_parent_or_self(&self, module_: Module<'a>) -> Module<'a> {
1460 if module_.is_normal() {
1463 match self.get_nearest_normal_module_parent(module_) {
1465 Some(new_module) => new_module,
1469 /// Resolves a "module prefix". A module prefix is one or both of (a) `self::`;
1470 /// (b) some chain of `super::`.
1471 /// grammar: (SELF MOD_SEP ) ? (SUPER MOD_SEP) *
1472 fn resolve_module_prefix(&mut self, module_path: &[Name], span: Span)
1473 -> ResolveResult<ModulePrefixResult<'a>> {
1474 // Start at the current module if we see `self` or `super`, or at the
1475 // top of the crate otherwise.
1476 let mut i = match &*module_path[0].as_str() {
1479 _ => return Success(NoPrefixFound),
1481 let module_ = self.current_module;
1482 let mut containing_module = self.get_nearest_normal_module_parent_or_self(module_);
1484 // Now loop through all the `super`s we find.
1485 while i < module_path.len() && "super" == module_path[i].as_str() {
1486 debug!("(resolving module prefix) resolving `super` at {}",
1487 module_to_string(&containing_module));
1488 match self.get_nearest_normal_module_parent(containing_module) {
1490 let msg = "There are too many initial `super`s.".into();
1491 return Failed(Some((span, msg)));
1493 Some(new_module) => {
1494 containing_module = new_module;
1500 debug!("(resolving module prefix) finished resolving prefix at {}",
1501 module_to_string(&containing_module));
1503 return Success(PrefixFound(containing_module, i));
1506 /// Attempts to resolve the supplied name in the given module for the
1507 /// given namespace. If successful, returns the binding corresponding to
1509 fn resolve_name_in_module(&mut self,
1512 namespace: Namespace,
1513 use_lexical_scope: bool,
1515 -> ResolveResult<&'a NameBinding<'a>> {
1516 debug!("(resolving name in module) resolving `{}` in `{}`", name, module_to_string(module));
1518 self.populate_module_if_necessary(module);
1519 module.resolve_name(name, namespace, use_lexical_scope).and_then(|binding| {
1521 if let NameBindingKind::Import { directive, .. } = binding.kind {
1522 self.used_imports.insert((directive.id, namespace));
1524 self.record_use(name, binding);
1532 // We maintain a list of value ribs and type ribs.
1534 // Simultaneously, we keep track of the current position in the module
1535 // graph in the `current_module` pointer. When we go to resolve a name in
1536 // the value or type namespaces, we first look through all the ribs and
1537 // then query the module graph. When we resolve a name in the module
1538 // namespace, we can skip all the ribs (since nested modules are not
1539 // allowed within blocks in Rust) and jump straight to the current module
1542 // Named implementations are handled separately. When we find a method
1543 // call, we consult the module node to find all of the implementations in
1544 // scope. This information is lazily cached in the module node. We then
1545 // generate a fake "implementation scope" containing all the
1546 // implementations thus found, for compatibility with old resolve pass.
1548 fn with_scope<F>(&mut self, id: NodeId, f: F)
1549 where F: FnOnce(&mut Resolver)
1551 let module = self.module_map.get(&id).cloned(); // clones a reference
1552 if let Some(module) = module {
1553 // Move down in the graph.
1554 let orig_module = ::std::mem::replace(&mut self.current_module, module);
1555 self.value_ribs.push(Rib::new(ModuleRibKind(module)));
1556 self.type_ribs.push(Rib::new(ModuleRibKind(module)));
1560 self.current_module = orig_module;
1561 self.value_ribs.pop();
1562 self.type_ribs.pop();
1568 /// Searches the current set of local scopes for labels.
1569 /// Stops after meeting a closure.
1570 fn search_label(&self, name: Name) -> Option<Def> {
1571 for rib in self.label_ribs.iter().rev() {
1577 // Do not resolve labels across function boundary
1581 let result = rib.bindings.get(&name).cloned();
1582 if result.is_some() {
1589 fn resolve_item(&mut self, item: &Item) {
1590 let name = item.ident.name;
1592 debug!("(resolving item) resolving {}", name);
1595 ItemKind::Enum(_, ref generics) |
1596 ItemKind::Ty(_, ref generics) |
1597 ItemKind::Struct(_, ref generics) => {
1598 self.with_type_parameter_rib(HasTypeParameters(generics, TypeSpace, ItemRibKind),
1599 |this| visit::walk_item(this, item));
1601 ItemKind::Fn(_, _, _, _, ref generics, _) => {
1602 self.with_type_parameter_rib(HasTypeParameters(generics, FnSpace, ItemRibKind),
1603 |this| visit::walk_item(this, item));
1606 ItemKind::DefaultImpl(_, ref trait_ref) => {
1607 self.with_optional_trait_ref(Some(trait_ref), |_, _| {});
1609 ItemKind::Impl(_, _, ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1610 self.resolve_implementation(generics,
1616 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1617 // Create a new rib for the trait-wide type parameters.
1618 self.with_type_parameter_rib(HasTypeParameters(generics,
1622 let local_def_id = this.definitions.local_def_id(item.id);
1623 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1624 this.visit_generics(generics);
1625 walk_list!(this, visit_ty_param_bound, bounds);
1627 for trait_item in trait_items {
1628 match trait_item.node {
1629 TraitItemKind::Const(_, ref default) => {
1630 // Only impose the restrictions of
1631 // ConstRibKind if there's an actual constant
1632 // expression in a provided default.
1633 if default.is_some() {
1634 this.with_constant_rib(|this| {
1635 visit::walk_trait_item(this, trait_item)
1638 visit::walk_trait_item(this, trait_item)
1641 TraitItemKind::Method(ref sig, _) => {
1642 let type_parameters =
1643 HasTypeParameters(&sig.generics,
1645 MethodRibKind(!sig.decl.has_self()));
1646 this.with_type_parameter_rib(type_parameters, |this| {
1647 visit::walk_trait_item(this, trait_item)
1650 TraitItemKind::Type(..) => {
1651 this.with_type_parameter_rib(NoTypeParameters, |this| {
1652 visit::walk_trait_item(this, trait_item)
1655 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1662 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1663 self.with_scope(item.id, |this| {
1664 visit::walk_item(this, item);
1668 ItemKind::Const(..) | ItemKind::Static(..) => {
1669 self.with_constant_rib(|this| {
1670 visit::walk_item(this, item);
1674 ItemKind::Use(ref view_path) => {
1675 match view_path.node {
1676 ast::ViewPathList(ref prefix, ref items) => {
1677 // Resolve prefix of an import with empty braces (issue #28388)
1678 if items.is_empty() && !prefix.segments.is_empty() {
1679 match self.resolve_crate_relative_path(prefix.span,
1683 let def = binding.def().unwrap();
1684 self.record_def(item.id, PathResolution::new(def));
1686 Err(true) => self.record_def(item.id, err_path_resolution()),
1690 ResolutionError::FailedToResolve(
1691 &path_names_to_string(prefix, 0)));
1692 self.record_def(item.id, err_path_resolution());
1701 ItemKind::ExternCrate(_) => {
1702 // do nothing, these are just around to be encoded
1705 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1709 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1710 where F: FnOnce(&mut Resolver)
1712 match type_parameters {
1713 HasTypeParameters(generics, space, rib_kind) => {
1714 let mut function_type_rib = Rib::new(rib_kind);
1715 let mut seen_bindings = HashSet::new();
1716 for (index, type_parameter) in generics.ty_params.iter().enumerate() {
1717 let name = type_parameter.ident.name;
1718 debug!("with_type_parameter_rib: {}", type_parameter.id);
1720 if seen_bindings.contains(&name) {
1722 type_parameter.span,
1723 ResolutionError::NameAlreadyUsedInTypeParameterList(name));
1725 seen_bindings.insert(name);
1727 // plain insert (no renaming)
1728 let def_id = self.definitions.local_def_id(type_parameter.id);
1729 let def = Def::TyParam(space, index as u32, def_id, name);
1730 function_type_rib.bindings.insert(name, def);
1732 self.type_ribs.push(function_type_rib);
1735 NoTypeParameters => {
1742 if let HasTypeParameters(..) = type_parameters {
1743 self.type_ribs.pop();
1747 fn with_label_rib<F>(&mut self, f: F)
1748 where F: FnOnce(&mut Resolver)
1750 self.label_ribs.push(Rib::new(NormalRibKind));
1752 self.label_ribs.pop();
1755 fn with_constant_rib<F>(&mut self, f: F)
1756 where F: FnOnce(&mut Resolver)
1758 self.value_ribs.push(Rib::new(ConstantItemRibKind));
1759 self.type_ribs.push(Rib::new(ConstantItemRibKind));
1761 self.type_ribs.pop();
1762 self.value_ribs.pop();
1765 fn resolve_function(&mut self,
1766 rib_kind: RibKind<'a>,
1767 declaration: &FnDecl,
1769 // Create a value rib for the function.
1770 self.value_ribs.push(Rib::new(rib_kind));
1772 // Create a label rib for the function.
1773 self.label_ribs.push(Rib::new(rib_kind));
1775 // Add each argument to the rib.
1776 let mut bindings_list = HashMap::new();
1777 for argument in &declaration.inputs {
1778 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
1780 self.visit_ty(&argument.ty);
1782 debug!("(resolving function) recorded argument");
1784 visit::walk_fn_ret_ty(self, &declaration.output);
1786 // Resolve the function body.
1787 self.visit_block(block);
1789 debug!("(resolving function) leaving function");
1791 self.label_ribs.pop();
1792 self.value_ribs.pop();
1795 fn resolve_trait_reference(&mut self,
1799 -> Result<PathResolution, ()> {
1800 self.resolve_path(id, trait_path, path_depth, TypeNS).and_then(|path_res| {
1801 if let Def::Trait(_) = path_res.base_def {
1802 debug!("(resolving trait) found trait def: {:?}", path_res);
1806 resolve_struct_error(self,
1808 ResolutionError::IsNotATrait(&path_names_to_string(trait_path,
1811 // If it's a typedef, give a note
1812 if let Def::TyAlias(..) = path_res.base_def {
1813 let trait_name = trait_path.segments.last().unwrap().identifier.name;
1814 err.span_label(trait_path.span,
1815 &format!("`{}` is not a trait", trait_name));
1817 let definition_site = {
1818 let segments = &trait_path.segments;
1819 if trait_path.global {
1820 self.resolve_crate_relative_path(trait_path.span, segments, TypeNS)
1822 self.resolve_module_relative_path(trait_path.span, segments, TypeNS)
1823 }.map(|binding| binding.span).unwrap_or(syntax_pos::DUMMY_SP)
1826 if definition_site != syntax_pos::DUMMY_SP {
1827 err.span_label(definition_site,
1828 &format!("type aliases cannot be used for traits"));
1834 }).map_err(|error_reported| {
1835 if error_reported { return }
1837 // find possible candidates
1838 let trait_name = trait_path.segments.last().unwrap().identifier.name;
1840 self.lookup_candidates(
1844 Def::Trait(_) => true,
1849 // create error object
1850 let name = &path_names_to_string(trait_path, path_depth);
1852 ResolutionError::UndeclaredTraitName(
1857 resolve_error(self, trait_path.span, error);
1861 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1862 where F: FnOnce(&mut Resolver) -> T
1864 // Handle nested impls (inside fn bodies)
1865 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1866 let result = f(self);
1867 self.current_self_type = previous_value;
1871 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1872 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1874 let mut new_val = None;
1875 let mut new_id = None;
1876 if let Some(trait_ref) = opt_trait_ref {
1877 if let Ok(path_res) = self.resolve_trait_reference(trait_ref.ref_id,
1880 assert!(path_res.depth == 0);
1881 self.record_def(trait_ref.ref_id, path_res);
1882 new_val = Some((path_res.base_def.def_id(), trait_ref.clone()));
1883 new_id = Some(path_res.base_def.def_id());
1885 self.record_def(trait_ref.ref_id, err_path_resolution());
1887 visit::walk_trait_ref(self, trait_ref);
1889 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1890 let result = f(self, new_id);
1891 self.current_trait_ref = original_trait_ref;
1895 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1896 where F: FnOnce(&mut Resolver)
1898 let mut self_type_rib = Rib::new(NormalRibKind);
1900 // plain insert (no renaming, types are not currently hygienic....)
1901 self_type_rib.bindings.insert(keywords::SelfType.name(), self_def);
1902 self.type_ribs.push(self_type_rib);
1904 self.type_ribs.pop();
1907 fn resolve_implementation(&mut self,
1908 generics: &Generics,
1909 opt_trait_reference: &Option<TraitRef>,
1912 impl_items: &[ImplItem]) {
1913 // If applicable, create a rib for the type parameters.
1914 self.with_type_parameter_rib(HasTypeParameters(generics,
1918 // Resolve the type parameters.
1919 this.visit_generics(generics);
1921 // Resolve the trait reference, if necessary.
1922 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1923 // Resolve the self type.
1924 this.visit_ty(self_type);
1926 this.with_self_rib(Def::SelfTy(trait_id, Some(item_id)), |this| {
1927 this.with_current_self_type(self_type, |this| {
1928 for impl_item in impl_items {
1929 this.resolve_visibility(&impl_item.vis);
1930 match impl_item.node {
1931 ImplItemKind::Const(..) => {
1932 // If this is a trait impl, ensure the const
1934 this.check_trait_item(impl_item.ident.name,
1936 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
1937 visit::walk_impl_item(this, impl_item);
1939 ImplItemKind::Method(ref sig, _) => {
1940 // If this is a trait impl, ensure the method
1942 this.check_trait_item(impl_item.ident.name,
1944 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
1946 // We also need a new scope for the method-
1947 // specific type parameters.
1948 let type_parameters =
1949 HasTypeParameters(&sig.generics,
1951 MethodRibKind(!sig.decl.has_self()));
1952 this.with_type_parameter_rib(type_parameters, |this| {
1953 visit::walk_impl_item(this, impl_item);
1956 ImplItemKind::Type(ref ty) => {
1957 // If this is a trait impl, ensure the type
1959 this.check_trait_item(impl_item.ident.name,
1961 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
1965 ImplItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1974 fn check_trait_item<F>(&self, name: Name, span: Span, err: F)
1975 where F: FnOnce(Name, &str) -> ResolutionError
1977 // If there is a TraitRef in scope for an impl, then the method must be in the
1979 if let Some((did, ref trait_ref)) = self.current_trait_ref {
1980 if !self.trait_item_map.contains_key(&(name, did)) {
1981 let path_str = path_names_to_string(&trait_ref.path, 0);
1982 resolve_error(self, span, err(name, &path_str));
1987 fn resolve_local(&mut self, local: &Local) {
1988 // Resolve the type.
1989 walk_list!(self, visit_ty, &local.ty);
1991 // Resolve the initializer.
1992 walk_list!(self, visit_expr, &local.init);
1994 // Resolve the pattern.
1995 self.resolve_pattern(&local.pat, PatternSource::Let, &mut HashMap::new());
1998 // build a map from pattern identifiers to binding-info's.
1999 // this is done hygienically. This could arise for a macro
2000 // that expands into an or-pattern where one 'x' was from the
2001 // user and one 'x' came from the macro.
2002 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2003 let mut binding_map = HashMap::new();
2005 pat.walk(&mut |pat| {
2006 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2007 if sub_pat.is_some() || match self.def_map.get(&pat.id) {
2008 Some(&PathResolution { base_def: Def::Local(..), .. }) => true,
2011 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2012 binding_map.insert(mtwt::resolve(ident.node), binding_info);
2021 // check that all of the arms in an or-pattern have exactly the
2022 // same set of bindings, with the same binding modes for each.
2023 fn check_consistent_bindings(&mut self, arm: &Arm) {
2024 if arm.pats.is_empty() {
2027 let map_0 = self.binding_mode_map(&arm.pats[0]);
2028 for (i, p) in arm.pats.iter().enumerate() {
2029 let map_i = self.binding_mode_map(&p);
2031 for (&key, &binding_0) in &map_0 {
2032 match map_i.get(&key) {
2036 ResolutionError::VariableNotBoundInPattern(key, 1, i + 1));
2038 Some(binding_i) => {
2039 if binding_0.binding_mode != binding_i.binding_mode {
2042 ResolutionError::VariableBoundWithDifferentMode(key,
2049 for (&key, &binding) in &map_i {
2050 if !map_0.contains_key(&key) {
2053 ResolutionError::VariableNotBoundInPattern(key, i + 1, 1));
2059 fn resolve_arm(&mut self, arm: &Arm) {
2060 self.value_ribs.push(Rib::new(NormalRibKind));
2062 let mut bindings_list = HashMap::new();
2063 for pattern in &arm.pats {
2064 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2067 // This has to happen *after* we determine which
2068 // pat_idents are variants
2069 self.check_consistent_bindings(arm);
2071 walk_list!(self, visit_expr, &arm.guard);
2072 self.visit_expr(&arm.body);
2074 self.value_ribs.pop();
2077 fn resolve_block(&mut self, block: &Block) {
2078 debug!("(resolving block) entering block");
2079 // Move down in the graph, if there's an anonymous module rooted here.
2080 let orig_module = self.current_module;
2081 let anonymous_module = self.module_map.get(&block.id).cloned(); // clones a reference
2083 if let Some(anonymous_module) = anonymous_module {
2084 debug!("(resolving block) found anonymous module, moving down");
2085 self.value_ribs.push(Rib::new(ModuleRibKind(anonymous_module)));
2086 self.type_ribs.push(Rib::new(ModuleRibKind(anonymous_module)));
2087 self.current_module = anonymous_module;
2089 self.value_ribs.push(Rib::new(NormalRibKind));
2092 // Descend into the block.
2093 visit::walk_block(self, block);
2096 self.current_module = orig_module;
2097 self.value_ribs.pop();
2098 if let Some(_) = anonymous_module {
2099 self.type_ribs.pop();
2101 debug!("(resolving block) leaving block");
2104 fn resolve_type(&mut self, ty: &Ty) {
2106 TyKind::Path(ref maybe_qself, ref path) => {
2107 // This is a path in the type namespace. Walk through scopes
2109 if let Some(def) = self.resolve_possibly_assoc_item(ty.id, maybe_qself.as_ref(),
2111 match def.base_def {
2112 Def::Mod(..) if def.depth == 0 => {
2113 self.session.span_err(path.span, "expected type, found module");
2114 self.record_def(ty.id, err_path_resolution());
2117 // Write the result into the def map.
2118 debug!("(resolving type) writing resolution for `{}` (id {}) = {:?}",
2119 path_names_to_string(path, 0), ty.id, def);
2120 self.record_def(ty.id, def);
2124 self.record_def(ty.id, err_path_resolution());
2126 // Keep reporting some errors even if they're ignored above.
2127 if let Err(true) = self.resolve_path(ty.id, path, 0, TypeNS) {
2128 // `resolve_path` already reported the error
2130 let kind = if maybe_qself.is_some() {
2136 let is_invalid_self_type_name = path.segments.len() > 0 &&
2137 maybe_qself.is_none() &&
2138 path.segments[0].identifier.name ==
2139 keywords::SelfType.name();
2140 if is_invalid_self_type_name {
2143 ResolutionError::SelfUsedOutsideImplOrTrait);
2145 let segment = path.segments.last();
2146 let segment = segment.expect("missing name in path");
2147 let type_name = segment.identifier.name;
2150 self.lookup_candidates(
2157 Def::TyAlias(_) => true,
2162 // create error object
2163 let name = &path_names_to_string(path, 0);
2165 ResolutionError::UseOfUndeclared(
2171 resolve_error(self, ty.span, error);
2178 // Resolve embedded types.
2179 visit::walk_ty(self, ty);
2182 fn fresh_binding(&mut self,
2183 ident: &ast::SpannedIdent,
2185 outer_pat_id: NodeId,
2186 pat_src: PatternSource,
2187 bindings: &mut HashMap<Name, NodeId>)
2189 // Add the binding to the local ribs, if it
2190 // doesn't already exist in the bindings map. (We
2191 // must not add it if it's in the bindings map
2192 // because that breaks the assumptions later
2193 // passes make about or-patterns.)
2194 let renamed = mtwt::resolve(ident.node);
2195 let def = match bindings.get(&renamed).cloned() {
2196 Some(id) if id == outer_pat_id => {
2197 // `Variant(a, a)`, error
2201 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2202 &ident.node.name.as_str())
2206 Some(..) if pat_src == PatternSource::FnParam => {
2207 // `fn f(a: u8, a: u8)`, error
2211 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2212 &ident.node.name.as_str())
2216 Some(..) if pat_src == PatternSource::Match => {
2217 // `Variant1(a) | Variant2(a)`, ok
2218 // Reuse definition from the first `a`.
2219 self.value_ribs.last_mut().unwrap().bindings[&renamed]
2222 span_bug!(ident.span, "two bindings with the same name from \
2223 unexpected pattern source {:?}", pat_src);
2226 // A completely fresh binding, add to the lists.
2227 // FIXME: Later stages are not ready to deal with `Def::Err` here yet, so
2228 // define `Invalid` bindings as `Def::Local`, just don't add them to the lists.
2229 let def = Def::Local(self.definitions.local_def_id(pat_id), pat_id);
2230 if ident.node.name != keywords::Invalid.name() {
2231 bindings.insert(renamed, outer_pat_id);
2232 self.value_ribs.last_mut().unwrap().bindings.insert(renamed, def);
2238 PathResolution::new(def)
2241 fn resolve_pattern_path<ExpectedFn>(&mut self,
2243 qself: Option<&QSelf>,
2245 namespace: Namespace,
2246 expected_fn: ExpectedFn,
2247 expected_what: &str)
2248 where ExpectedFn: FnOnce(Def) -> bool
2250 let resolution = if let Some(resolution) = self.resolve_possibly_assoc_item(pat_id,
2251 qself, path, namespace) {
2252 if resolution.depth == 0 {
2253 if expected_fn(resolution.base_def) {
2259 ResolutionError::PatPathUnexpected(expected_what,
2260 resolution.kind_name(), path)
2262 err_path_resolution()
2265 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2266 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2267 // it needs to be added to the trait map.
2268 if namespace == ValueNS {
2269 let item_name = path.segments.last().unwrap().identifier.name;
2270 let traits = self.get_traits_containing_item(item_name);
2271 self.trait_map.insert(pat_id, traits);
2276 if let Err(false) = self.resolve_path(pat_id, path, 0, namespace) {
2280 ResolutionError::PatPathUnresolved(expected_what, path)
2283 err_path_resolution()
2286 self.record_def(pat_id, resolution);
2289 fn resolve_pattern(&mut self,
2291 pat_src: PatternSource,
2292 // Maps idents to the node ID for the
2293 // outermost pattern that binds them.
2294 bindings: &mut HashMap<Name, NodeId>) {
2295 // Visit all direct subpatterns of this pattern.
2296 let outer_pat_id = pat.id;
2297 pat.walk(&mut |pat| {
2299 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2300 // First try to resolve the identifier as some existing
2301 // entity, then fall back to a fresh binding.
2302 let local_def = self.resolve_identifier(ident.node, ValueNS, true);
2303 let resolution = if let Some(LocalDef { def, .. }) = local_def {
2304 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2305 bmode != BindingMode::ByValue(Mutability::Immutable);
2307 Def::Struct(..) | Def::Variant(..) |
2308 Def::Const(..) | Def::AssociatedConst(..) if !always_binding => {
2309 // A constant, unit variant, etc pattern.
2310 PathResolution::new(def)
2312 Def::Struct(..) | Def::Variant(..) |
2313 Def::Const(..) | Def::AssociatedConst(..) | Def::Static(..) => {
2314 // A fresh binding that shadows something unacceptable.
2315 let kind_name = PathResolution::new(def).kind_name();
2319 ResolutionError::BindingShadowsSomethingUnacceptable(
2320 pat_src.descr(), kind_name, ident.node.name)
2322 err_path_resolution()
2324 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2325 // These entities are explicitly allowed
2326 // to be shadowed by fresh bindings.
2327 self.fresh_binding(ident, pat.id, outer_pat_id,
2331 span_bug!(ident.span, "unexpected definition for an \
2332 identifier in pattern {:?}", def);
2336 // Fall back to a fresh binding.
2337 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2340 self.record_def(pat.id, resolution);
2343 PatKind::TupleStruct(ref path, _, _) => {
2344 self.resolve_pattern_path(pat.id, None, path, ValueNS, |def| {
2346 Def::Struct(..) | Def::Variant(..) | Def::Err => true,
2349 }, "variant or struct");
2352 PatKind::Path(ref qself, ref path) => {
2353 self.resolve_pattern_path(pat.id, qself.as_ref(), path, ValueNS, |def| {
2355 Def::Struct(..) | Def::Variant(..) |
2356 Def::Const(..) | Def::AssociatedConst(..) | Def::Err => true,
2359 }, "variant, struct or constant");
2362 PatKind::Struct(ref path, _, _) => {
2363 self.resolve_pattern_path(pat.id, None, path, TypeNS, |def| {
2365 Def::Struct(..) | Def::Variant(..) |
2366 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::Err => true,
2369 }, "variant, struct or type alias");
2377 visit::walk_pat(self, pat);
2380 /// Handles paths that may refer to associated items
2381 fn resolve_possibly_assoc_item(&mut self,
2383 maybe_qself: Option<&QSelf>,
2385 namespace: Namespace)
2386 -> Option<PathResolution> {
2387 let max_assoc_types;
2391 if qself.position == 0 {
2392 // FIXME: Create some fake resolution that can't possibly be a type.
2393 return Some(PathResolution {
2394 base_def: Def::Mod(self.definitions.local_def_id(ast::CRATE_NODE_ID)),
2395 depth: path.segments.len(),
2398 max_assoc_types = path.segments.len() - qself.position;
2399 // Make sure the trait is valid.
2400 let _ = self.resolve_trait_reference(id, path, max_assoc_types);
2403 max_assoc_types = path.segments.len();
2407 let mut resolution = self.with_no_errors(|this| {
2408 this.resolve_path(id, path, 0, namespace).ok()
2410 for depth in 1..max_assoc_types {
2411 if resolution.is_some() {
2414 self.with_no_errors(|this| {
2415 let partial_resolution = this.resolve_path(id, path, depth, TypeNS).ok();
2416 if let Some(Def::Mod(..)) = partial_resolution.map(|r| r.base_def) {
2417 // Modules cannot have associated items
2419 resolution = partial_resolution;
2426 /// Skips `path_depth` trailing segments, which is also reflected in the
2427 /// returned value. See `hir::def::PathResolution` for more info.
2428 fn resolve_path(&mut self, id: NodeId, path: &Path, path_depth: usize, namespace: Namespace)
2429 -> Result<PathResolution, bool /* true if an error was reported */ > {
2430 debug!("resolve_path(id={:?} path={:?}, path_depth={:?})", id, path, path_depth);
2432 let span = path.span;
2433 let segments = &path.segments[..path.segments.len() - path_depth];
2435 let mk_res = |def| PathResolution { base_def: def, depth: path_depth };
2438 let binding = self.resolve_crate_relative_path(span, segments, namespace);
2439 return binding.map(|binding| mk_res(binding.def().unwrap()));
2442 // Try to find a path to an item in a module.
2443 let last_ident = segments.last().unwrap().identifier;
2444 // Resolve a single identifier with fallback to primitive types
2445 let resolve_identifier_with_fallback = |this: &mut Self, record_used| {
2446 let def = this.resolve_identifier(last_ident, namespace, record_used);
2448 None | Some(LocalDef{def: Def::Mod(..), ..}) if namespace == TypeNS =>
2449 this.primitive_type_table
2451 .get(&last_ident.name)
2452 .map_or(def, |prim_ty| Some(LocalDef::from_def(Def::PrimTy(*prim_ty)))),
2457 if segments.len() == 1 {
2458 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2459 // don't report an error right away, but try to fallback to a primitive type.
2460 // So, we are still able to successfully resolve something like
2462 // use std::u8; // bring module u8 in scope
2463 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2464 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2465 // // not to non-existent std::u8::max_value
2468 // Such behavior is required for backward compatibility.
2469 // The same fallback is used when `a` resolves to nothing.
2470 let def = resolve_identifier_with_fallback(self, true).ok_or(false);
2471 return def.and_then(|def| self.adjust_local_def(def, span).ok_or(true)).map(mk_res);
2474 let unqualified_def = resolve_identifier_with_fallback(self, false);
2475 let qualified_binding = self.resolve_module_relative_path(span, segments, namespace);
2476 match (qualified_binding, unqualified_def) {
2477 (Ok(binding), Some(ref ud)) if binding.def().unwrap() == ud.def => {
2479 .add_lint(lint::builtin::UNUSED_QUALIFICATIONS,
2482 "unnecessary qualification".to_string());
2487 qualified_binding.map(|binding| mk_res(binding.def().unwrap()))
2490 // Resolve a single identifier
2491 fn resolve_identifier(&mut self,
2492 identifier: ast::Ident,
2493 namespace: Namespace,
2495 -> Option<LocalDef> {
2496 if identifier.name == keywords::Invalid.name() {
2497 return Some(LocalDef::from_def(Def::Err));
2500 self.resolve_ident_in_lexical_scope(identifier, namespace, record_used)
2501 .map(LexicalScopeBinding::local_def)
2504 // Resolve a local definition, potentially adjusting for closures.
2505 fn adjust_local_def(&mut self, local_def: LocalDef, span: Span) -> Option<Def> {
2506 let ribs = match local_def.ribs {
2507 Some((TypeNS, i)) => &self.type_ribs[i + 1..],
2508 Some((ValueNS, i)) => &self.value_ribs[i + 1..],
2511 let mut def = local_def.def;
2514 span_bug!(span, "unexpected {:?} in bindings", def)
2516 Def::Local(_, node_id) => {
2519 NormalRibKind | ModuleRibKind(..) => {
2520 // Nothing to do. Continue.
2522 ClosureRibKind(function_id) => {
2524 let node_def_id = self.definitions.local_def_id(node_id);
2526 let seen = self.freevars_seen
2528 .or_insert_with(|| NodeMap());
2529 if let Some(&index) = seen.get(&node_id) {
2530 def = Def::Upvar(node_def_id, node_id, index, function_id);
2533 let vec = self.freevars
2535 .or_insert_with(|| vec![]);
2536 let depth = vec.len();
2542 def = Def::Upvar(node_def_id, node_id, depth, function_id);
2543 seen.insert(node_id, depth);
2545 ItemRibKind | MethodRibKind(_) => {
2546 // This was an attempt to access an upvar inside a
2547 // named function item. This is not allowed, so we
2551 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2554 ConstantItemRibKind => {
2555 // Still doesn't deal with upvars
2558 ResolutionError::AttemptToUseNonConstantValueInConstant);
2564 Def::TyParam(..) | Def::SelfTy(..) => {
2567 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2568 ModuleRibKind(..) => {
2569 // Nothing to do. Continue.
2572 // This was an attempt to use a type parameter outside
2577 ResolutionError::TypeParametersFromOuterFunction);
2580 ConstantItemRibKind => {
2582 resolve_error(self, span, ResolutionError::OuterTypeParameterContext);
2593 // resolve a "module-relative" path, e.g. a::b::c
2594 fn resolve_module_relative_path(&mut self,
2596 segments: &[ast::PathSegment],
2597 namespace: Namespace)
2598 -> Result<&'a NameBinding<'a>,
2599 bool /* true if an error was reported */> {
2600 let module_path = segments.split_last()
2604 .map(|ps| ps.identifier.name)
2605 .collect::<Vec<_>>();
2607 let containing_module;
2608 match self.resolve_module_path(&module_path, UseLexicalScope, span) {
2610 let (span, msg) = match err {
2611 Some((span, msg)) => (span, msg),
2613 let msg = format!("Use of undeclared type or module `{}`",
2614 names_to_string(&module_path));
2619 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2622 Indeterminate => return Err(false),
2623 Success(resulting_module) => {
2624 containing_module = resulting_module;
2628 let name = segments.last().unwrap().identifier.name;
2629 let result = self.resolve_name_in_module(containing_module, name, namespace, false, true);
2630 result.success().map(|binding| {
2631 self.check_privacy(name, binding, span);
2636 /// Invariant: This must be called only during main resolution, not during
2637 /// import resolution.
2638 fn resolve_crate_relative_path<T>(&mut self, span: Span, segments: &[T], namespace: Namespace)
2639 -> Result<&'a NameBinding<'a>,
2640 bool /* true if an error was reported */>
2643 let module_path = segments.split_last().unwrap().1.iter().map(T::name).collect::<Vec<_>>();
2644 let root_module = self.graph_root;
2646 let containing_module;
2647 match self.resolve_module_path_from_root(root_module,
2652 let (span, msg) = match err {
2653 Some((span, msg)) => (span, msg),
2655 let msg = format!("Use of undeclared module `::{}`",
2656 names_to_string(&module_path));
2661 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2665 Indeterminate => return Err(false),
2667 Success(resulting_module) => {
2668 containing_module = resulting_module;
2672 let name = segments.last().unwrap().name();
2673 let result = self.resolve_name_in_module(containing_module, name, namespace, false, true);
2674 result.success().map(|binding| {
2675 self.check_privacy(name, binding, span);
2680 fn with_no_errors<T, F>(&mut self, f: F) -> T
2681 where F: FnOnce(&mut Resolver) -> T
2683 self.emit_errors = false;
2685 self.emit_errors = true;
2689 fn find_fallback_in_self_type(&mut self, name: Name) -> FallbackSuggestion {
2690 fn extract_node_id(t: &Ty) -> Option<NodeId> {
2692 TyKind::Path(None, _) => Some(t.id),
2693 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
2694 // This doesn't handle the remaining `Ty` variants as they are not
2695 // that commonly the self_type, it might be interesting to provide
2696 // support for those in future.
2701 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
2702 // Look for a field with the same name in the current self_type.
2703 if let Some(resolution) = self.def_map.get(&node_id) {
2704 match resolution.base_def {
2705 Def::Enum(did) | Def::TyAlias(did) |
2706 Def::Struct(did) | Def::Variant(_, did) if resolution.depth == 0 => {
2707 if let Some(fields) = self.structs.get(&did) {
2708 if fields.iter().any(|&field_name| name == field_name) {
2718 // Look for a method in the current trait.
2719 if let Some((trait_did, ref trait_ref)) = self.current_trait_ref {
2720 if let Some(&is_static_method) = self.trait_item_map.get(&(name, trait_did)) {
2721 if is_static_method {
2722 return TraitMethod(path_names_to_string(&trait_ref.path, 0));
2732 fn find_best_match(&mut self, name: &str) -> SuggestionType {
2733 if let Some(macro_name) = self.session.available_macros
2734 .borrow().iter().find(|n| n.as_str() == name) {
2735 return SuggestionType::Macro(format!("{}!", macro_name));
2738 let names = self.value_ribs
2741 .flat_map(|rib| rib.bindings.keys());
2743 if let Some(found) = find_best_match_for_name(names, name, None) {
2745 return SuggestionType::Function(found);
2747 } SuggestionType::NotFound
2750 fn resolve_labeled_block(&mut self, label: Option<ast::Ident>, id: NodeId, block: &Block) {
2751 if let Some(label) = label {
2752 let (label, def) = (mtwt::resolve(label), Def::Label(id));
2753 self.with_label_rib(|this| {
2754 this.label_ribs.last_mut().unwrap().bindings.insert(label, def);
2755 this.visit_block(block);
2758 self.visit_block(block);
2762 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
2763 // First, record candidate traits for this expression if it could
2764 // result in the invocation of a method call.
2766 self.record_candidate_traits_for_expr_if_necessary(expr);
2768 // Next, resolve the node.
2770 ExprKind::Path(ref maybe_qself, ref path) => {
2771 // This is a local path in the value namespace. Walk through
2772 // scopes looking for it.
2773 if let Some(path_res) = self.resolve_possibly_assoc_item(expr.id,
2774 maybe_qself.as_ref(), path, ValueNS) {
2775 // Check if struct variant
2776 let is_struct_variant = if let Def::Variant(_, variant_id) = path_res.base_def {
2777 self.structs.contains_key(&variant_id)
2781 if is_struct_variant {
2782 let _ = self.structs.contains_key(&path_res.base_def.def_id());
2783 let path_name = path_names_to_string(path, 0);
2785 let mut err = resolve_struct_error(self,
2787 ResolutionError::StructVariantUsedAsFunction(&path_name));
2789 let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
2791 if self.emit_errors {
2794 err.span_help(expr.span, &msg);
2797 self.record_def(expr.id, err_path_resolution());
2799 // Write the result into the def map.
2800 debug!("(resolving expr) resolved `{}`",
2801 path_names_to_string(path, 0));
2803 // Partial resolutions will need the set of traits in scope,
2804 // so they can be completed during typeck.
2805 if path_res.depth != 0 {
2806 let method_name = path.segments.last().unwrap().identifier.name;
2807 let traits = self.get_traits_containing_item(method_name);
2808 self.trait_map.insert(expr.id, traits);
2811 self.record_def(expr.id, path_res);
2814 // Be helpful if the name refers to a struct
2815 // (The pattern matching def_tys where the id is in self.structs
2816 // matches on regular structs while excluding tuple- and enum-like
2817 // structs, which wouldn't result in this error.)
2818 let path_name = path_names_to_string(path, 0);
2819 let type_res = self.with_no_errors(|this| {
2820 this.resolve_path(expr.id, path, 0, TypeNS)
2823 self.record_def(expr.id, err_path_resolution());
2825 if let Ok(Def::Struct(..)) = type_res.map(|r| r.base_def) {
2827 ResolutionError::StructVariantUsedAsFunction(&path_name);
2828 let mut err = resolve_struct_error(self, expr.span, error_variant);
2830 let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
2833 if self.emit_errors {
2836 err.span_help(expr.span, &msg);
2840 // Keep reporting some errors even if they're ignored above.
2841 if let Err(true) = self.resolve_path(expr.id, path, 0, ValueNS) {
2842 // `resolve_path` already reported the error
2844 let mut method_scope = false;
2845 let mut is_static = false;
2846 self.value_ribs.iter().rev().all(|rib| {
2847 method_scope = match rib.kind {
2848 MethodRibKind(is_static_) => {
2849 is_static = is_static_;
2852 ItemRibKind | ConstantItemRibKind => false,
2853 _ => return true, // Keep advancing
2855 false // Stop advancing
2859 &path_name[..] == keywords::SelfValue.name().as_str() {
2862 ResolutionError::SelfNotAvailableInStaticMethod);
2864 let last_name = path.segments.last().unwrap().identifier.name;
2865 let (mut msg, is_field) =
2866 match self.find_fallback_in_self_type(last_name) {
2868 // limit search to 5 to reduce the number
2869 // of stupid suggestions
2870 (match self.find_best_match(&path_name) {
2871 SuggestionType::Macro(s) => {
2872 format!("the macro `{}`", s)
2874 SuggestionType::Function(s) => format!("`{}`", s),
2875 SuggestionType::NotFound => "".to_string(),
2879 (if is_static && method_scope {
2882 format!("`self.{}`", path_name)
2885 TraitItem => (format!("to call `self.{}`", path_name), false),
2886 TraitMethod(path_str) =>
2887 (format!("to call `{}::{}`", path_str, path_name), false),
2890 let mut context = UnresolvedNameContext::Other;
2891 let mut def = Def::Err;
2892 if !msg.is_empty() {
2893 msg = format!(". Did you mean {}?", msg);
2895 // we check if this a module and if so, we display a help
2897 let name_path = path.segments.iter()
2898 .map(|seg| seg.identifier.name)
2899 .collect::<Vec<_>>();
2901 match self.resolve_module_path(&name_path[..],
2905 if let Some(def_type) = e.def {
2908 context = UnresolvedNameContext::PathIsMod(parent);
2916 ResolutionError::UnresolvedName {
2920 is_static_method: method_scope && is_static,
2929 visit::walk_expr(self, expr);
2932 ExprKind::Struct(ref path, _, _) => {
2933 // Resolve the path to the structure it goes to. We don't
2934 // check to ensure that the path is actually a structure; that
2935 // is checked later during typeck.
2936 match self.resolve_path(expr.id, path, 0, TypeNS) {
2937 Ok(definition) => self.record_def(expr.id, definition),
2938 Err(true) => self.record_def(expr.id, err_path_resolution()),
2940 debug!("(resolving expression) didn't find struct def",);
2944 ResolutionError::DoesNotNameAStruct(
2945 &path_names_to_string(path, 0))
2947 self.record_def(expr.id, err_path_resolution());
2951 visit::walk_expr(self, expr);
2954 ExprKind::Loop(_, Some(label)) | ExprKind::While(_, _, Some(label)) => {
2955 self.with_label_rib(|this| {
2956 let def = Def::Label(expr.id);
2959 let rib = this.label_ribs.last_mut().unwrap();
2960 rib.bindings.insert(mtwt::resolve(label.node), def);
2963 visit::walk_expr(this, expr);
2967 ExprKind::Break(Some(label)) | ExprKind::Continue(Some(label)) => {
2968 match self.search_label(mtwt::resolve(label.node)) {
2970 self.record_def(expr.id, err_path_resolution());
2973 ResolutionError::UndeclaredLabel(&label.node.name.as_str()))
2975 Some(def @ Def::Label(_)) => {
2976 // Since this def is a label, it is never read.
2977 self.record_def(expr.id, PathResolution::new(def))
2980 span_bug!(expr.span, "label wasn't mapped to a label def!")
2985 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
2986 self.visit_expr(subexpression);
2988 self.value_ribs.push(Rib::new(NormalRibKind));
2989 self.resolve_pattern(pattern, PatternSource::IfLet, &mut HashMap::new());
2990 self.visit_block(if_block);
2991 self.value_ribs.pop();
2993 optional_else.as_ref().map(|expr| self.visit_expr(expr));
2996 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
2997 self.visit_expr(subexpression);
2998 self.value_ribs.push(Rib::new(NormalRibKind));
2999 self.resolve_pattern(pattern, PatternSource::WhileLet, &mut HashMap::new());
3001 self.resolve_labeled_block(label.map(|l| l.node), expr.id, block);
3003 self.value_ribs.pop();
3006 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3007 self.visit_expr(subexpression);
3008 self.value_ribs.push(Rib::new(NormalRibKind));
3009 self.resolve_pattern(pattern, PatternSource::For, &mut HashMap::new());
3011 self.resolve_labeled_block(label.map(|l| l.node), expr.id, block);
3013 self.value_ribs.pop();
3016 ExprKind::Field(ref subexpression, _) => {
3017 self.resolve_expr(subexpression, Some(expr));
3019 ExprKind::MethodCall(_, ref types, ref arguments) => {
3020 let mut arguments = arguments.iter();
3021 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3022 for argument in arguments {
3023 self.resolve_expr(argument, None);
3025 for ty in types.iter() {
3031 visit::walk_expr(self, expr);
3036 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3038 ExprKind::Field(_, name) => {
3039 // FIXME(#6890): Even though you can't treat a method like a
3040 // field, we need to add any trait methods we find that match
3041 // the field name so that we can do some nice error reporting
3042 // later on in typeck.
3043 let traits = self.get_traits_containing_item(name.node.name);
3044 self.trait_map.insert(expr.id, traits);
3046 ExprKind::MethodCall(name, _, _) => {
3047 debug!("(recording candidate traits for expr) recording traits for {}",
3049 let traits = self.get_traits_containing_item(name.node.name);
3050 self.trait_map.insert(expr.id, traits);
3058 fn get_traits_containing_item(&mut self, name: Name) -> Vec<TraitCandidate> {
3059 debug!("(getting traits containing item) looking for '{}'", name);
3061 fn add_trait_info(found_traits: &mut Vec<TraitCandidate>,
3062 trait_def_id: DefId,
3063 import_id: Option<NodeId>,
3065 debug!("(adding trait info) found trait {:?} for method '{}'",
3068 found_traits.push(TraitCandidate {
3069 def_id: trait_def_id,
3070 import_id: import_id,
3074 let mut found_traits = Vec::new();
3075 // Look for the current trait.
3076 if let Some((trait_def_id, _)) = self.current_trait_ref {
3077 if self.trait_item_map.contains_key(&(name, trait_def_id)) {
3078 add_trait_info(&mut found_traits, trait_def_id, None, name);
3082 let mut search_module = self.current_module;
3084 // Look for trait children.
3085 let mut search_in_module = |this: &mut Self, module: Module<'a>| {
3086 let mut traits = module.traits.borrow_mut();
3087 if traits.is_none() {
3088 let mut collected_traits = Vec::new();
3089 module.for_each_child(|name, ns, binding| {
3090 if ns != TypeNS { return }
3091 if let Some(Def::Trait(_)) = binding.def() {
3092 collected_traits.push((name, binding));
3095 *traits = Some(collected_traits.into_boxed_slice());
3098 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3099 let trait_def_id = binding.def().unwrap().def_id();
3100 if this.trait_item_map.contains_key(&(name, trait_def_id)) {
3101 let mut import_id = None;
3102 if let NameBindingKind::Import { directive, .. } = binding.kind {
3103 let id = directive.id;
3104 this.maybe_unused_trait_imports.insert(id);
3105 import_id = Some(id);
3107 add_trait_info(&mut found_traits, trait_def_id, import_id, name);
3108 this.record_use(trait_name, binding);
3112 search_in_module(self, search_module);
3114 match search_module.parent_link {
3115 NoParentLink | ModuleParentLink(..) => {
3116 if !search_module.no_implicit_prelude.get() {
3117 self.prelude.map(|prelude| search_in_module(self, prelude));
3121 BlockParentLink(parent_module, _) => {
3122 search_module = parent_module;
3130 /// When name resolution fails, this method can be used to look up candidate
3131 /// entities with the expected name. It allows filtering them using the
3132 /// supplied predicate (which should be used to only accept the types of
3133 /// definitions expected e.g. traits). The lookup spans across all crates.
3135 /// NOTE: The method does not look into imports, but this is not a problem,
3136 /// since we report the definitions (thus, the de-aliased imports).
3137 fn lookup_candidates<FilterFn>(&mut self,
3139 namespace: Namespace,
3140 filter_fn: FilterFn) -> SuggestedCandidates
3141 where FilterFn: Fn(Def) -> bool {
3143 let mut lookup_results = Vec::new();
3144 let mut worklist = Vec::new();
3145 worklist.push((self.graph_root, Vec::new(), false));
3147 while let Some((in_module,
3149 in_module_is_extern)) = worklist.pop() {
3150 self.populate_module_if_necessary(in_module);
3152 in_module.for_each_child(|name, ns, name_binding| {
3154 // avoid imports entirely
3155 if name_binding.is_import() { return; }
3157 // collect results based on the filter function
3158 if let Some(def) = name_binding.def() {
3159 if name == lookup_name && ns == namespace && filter_fn(def) {
3161 let ident = ast::Ident::with_empty_ctxt(name);
3162 let params = PathParameters::none();
3163 let segment = PathSegment {
3167 let span = name_binding.span;
3168 let mut segms = path_segments.clone();
3169 segms.push(segment);
3175 // the entity is accessible in the following cases:
3176 // 1. if it's defined in the same crate, it's always
3177 // accessible (since private entities can be made public)
3178 // 2. if it's defined in another crate, it's accessible
3179 // only if both the module is public and the entity is
3180 // declared as public (due to pruning, we don't explore
3181 // outside crate private modules => no need to check this)
3182 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3183 lookup_results.push(path);
3188 // collect submodules to explore
3189 if let Some(module) = name_binding.module() {
3191 let path_segments = match module.parent_link {
3192 NoParentLink => path_segments.clone(),
3193 ModuleParentLink(_, name) => {
3194 let mut paths = path_segments.clone();
3195 let ident = ast::Ident::with_empty_ctxt(name);
3196 let params = PathParameters::none();
3197 let segm = PathSegment {
3207 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3208 // add the module to the lookup
3209 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3210 if !worklist.iter().any(|&(m, _, _)| m.def == module.def) {
3211 worklist.push((module, path_segments, is_extern));
3218 SuggestedCandidates {
3219 name: lookup_name.as_str().to_string(),
3220 candidates: lookup_results,
3224 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3225 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3226 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3227 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3231 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3232 let (path, id) = match *vis {
3233 ast::Visibility::Public => return ty::Visibility::Public,
3234 ast::Visibility::Crate(_) => return ty::Visibility::Restricted(ast::CRATE_NODE_ID),
3235 ast::Visibility::Restricted { ref path, id } => (path, id),
3236 ast::Visibility::Inherited => {
3237 let current_module =
3238 self.get_nearest_normal_module_parent_or_self(self.current_module);
3240 self.definitions.as_local_node_id(current_module.def_id().unwrap()).unwrap();
3241 return ty::Visibility::Restricted(id);
3245 let segments: Vec<_> = path.segments.iter().map(|seg| seg.identifier.name).collect();
3246 let mut path_resolution = err_path_resolution();
3247 let vis = match self.resolve_module_path(&segments, DontUseLexicalScope, path.span) {
3248 Success(module) => {
3249 let def = module.def.unwrap();
3250 path_resolution = PathResolution::new(def);
3251 ty::Visibility::Restricted(self.definitions.as_local_node_id(def.def_id()).unwrap())
3253 Failed(Some((span, msg))) => {
3254 self.session.span_err(span, &format!("failed to resolve module path. {}", msg));
3255 ty::Visibility::Public
3258 self.session.span_err(path.span, "unresolved module path");
3259 ty::Visibility::Public
3262 self.def_map.insert(id, path_resolution);
3263 if !self.is_accessible(vis) {
3264 let msg = format!("visibilities can only be restricted to ancestor modules");
3265 self.session.span_err(path.span, &msg);
3270 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3271 let current_module = self.get_nearest_normal_module_parent_or_self(self.current_module);
3272 let node_id = self.definitions.as_local_node_id(current_module.def_id().unwrap()).unwrap();
3273 vis.is_accessible_from(node_id, self)
3276 fn check_privacy(&mut self, name: Name, binding: &'a NameBinding<'a>, span: Span) {
3277 if !self.is_accessible(binding.vis) {
3278 self.privacy_errors.push(PrivacyError(span, name, binding));
3282 fn report_privacy_errors(&self) {
3283 if self.privacy_errors.len() == 0 { return }
3284 let mut reported_spans = HashSet::new();
3285 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3286 if !reported_spans.insert(span) { continue }
3287 if binding.is_extern_crate() {
3288 // Warn when using an inaccessible extern crate.
3289 let node_id = binding.module().unwrap().extern_crate_id.unwrap();
3290 let msg = format!("extern crate `{}` is private", name);
3291 self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
3293 let def = binding.def().unwrap();
3294 self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
3299 fn report_conflict(&self,
3303 binding: &NameBinding,
3304 old_binding: &NameBinding) {
3305 // Error on the second of two conflicting names
3306 if old_binding.span.lo > binding.span.lo {
3307 return self.report_conflict(parent, name, ns, old_binding, binding);
3310 let container = match parent.def {
3311 Some(Def::Mod(_)) => "module",
3312 Some(Def::Trait(_)) => "trait",
3317 let (participle, noun) = match old_binding.is_import() || old_binding.is_extern_crate() {
3318 true => ("imported", "import"),
3319 false => ("defined", "definition"),
3322 let span = binding.span;
3324 let kind = match (ns, old_binding.module()) {
3325 (ValueNS, _) => "a value",
3326 (TypeNS, Some(module)) if module.extern_crate_id.is_some() => "an extern crate",
3327 (TypeNS, Some(module)) if module.is_normal() => "a module",
3328 (TypeNS, Some(module)) if module.is_trait() => "a trait",
3329 (TypeNS, _) => "a type",
3331 format!("{} named `{}` has already been {} in this {}",
3332 kind, name, participle, container)
3335 let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
3336 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3337 (true, _) | (_, true) if binding.is_import() || old_binding.is_import() =>
3338 struct_span_err!(self.session, span, E0254, "{}", msg),
3339 (true, _) | (_, true) => struct_span_err!(self.session, span, E0260, "{}", msg),
3340 _ => match (old_binding.is_import(), binding.is_import()) {
3341 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3342 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3344 let mut e = struct_span_err!(self.session, span, E0255, "{}", msg);
3345 e.span_label(span, &format!("`{}` was already imported", name));
3351 if old_binding.span != syntax_pos::DUMMY_SP {
3352 err.span_label(old_binding.span, &format!("previous {} of `{}` here", noun, name));
3358 fn names_to_string(names: &[Name]) -> String {
3359 let mut first = true;
3360 let mut result = String::new();
3365 result.push_str("::")
3367 result.push_str(&name.as_str());
3372 fn path_names_to_string(path: &Path, depth: usize) -> String {
3373 let names: Vec<ast::Name> = path.segments[..path.segments.len() - depth]
3375 .map(|seg| seg.identifier.name)
3377 names_to_string(&names[..])
3380 /// When an entity with a given name is not available in scope, we search for
3381 /// entities with that name in all crates. This method allows outputting the
3382 /// results of this search in a programmer-friendly way
3383 fn show_candidates(session: &mut DiagnosticBuilder,
3384 candidates: &SuggestedCandidates) {
3386 let paths = &candidates.candidates;
3388 if paths.len() > 0 {
3389 // don't show more than MAX_CANDIDATES results, so
3390 // we're consistent with the trait suggestions
3391 const MAX_CANDIDATES: usize = 5;
3393 // we want consistent results across executions, but candidates are produced
3394 // by iterating through a hash map, so make sure they are ordered:
3395 let mut path_strings: Vec<_> = paths.into_iter()
3396 .map(|p| path_names_to_string(&p, 0))
3398 path_strings.sort();
3400 // behave differently based on how many candidates we have:
3401 if !paths.is_empty() {
3402 if paths.len() == 1 {
3404 &format!("you can import it into scope: `use {};`.",
3408 session.help("you can import several candidates \
3409 into scope (`use ...;`):");
3410 let count = path_strings.len() as isize - MAX_CANDIDATES as isize + 1;
3412 for (idx, path_string) in path_strings.iter().enumerate() {
3413 if idx == MAX_CANDIDATES - 1 && count > 1 {
3415 &format!(" and {} other candidates", count).to_string(),
3420 &format!(" `{}`", path_string).to_string(),
3429 &format!("no candidates by the name of `{}` found in your \
3430 project; maybe you misspelled the name or forgot to import \
3431 an external crate?", candidates.name.to_string()),
3436 /// A somewhat inefficient routine to obtain the name of a module.
3437 fn module_to_string(module: Module) -> String {
3438 let mut names = Vec::new();
3440 fn collect_mod(names: &mut Vec<ast::Name>, module: Module) {
3441 match module.parent_link {
3443 ModuleParentLink(ref module, name) => {
3445 collect_mod(names, module);
3447 BlockParentLink(ref module, _) => {
3448 // danger, shouldn't be ident?
3449 names.push(token::intern("<opaque>"));
3450 collect_mod(names, module);
3454 collect_mod(&mut names, module);
3456 if names.is_empty() {
3457 return "???".to_string();
3459 names_to_string(&names.into_iter().rev().collect::<Vec<ast::Name>>())
3462 fn err_path_resolution() -> PathResolution {
3463 PathResolution::new(Def::Err)
3466 #[derive(PartialEq,Copy, Clone)]
3467 pub enum MakeGlobMap {
3472 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }