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 #![crate_type = "dylib"]
13 #![crate_type = "rlib"]
14 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
15 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
16 html_root_url = "https://doc.rust-lang.org/nightly/")]
19 #![feature(rustc_diagnostic_macros)]
25 extern crate syntax_pos;
26 extern crate rustc_errors as errors;
31 use self::Namespace::*;
32 use self::TypeParameters::*;
35 use rustc::hir::map::{Definitions, DefCollector};
36 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
37 use rustc::middle::cstore::CrateLoader;
38 use rustc::session::Session;
40 use rustc::hir::def::*;
41 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
43 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
44 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
46 use syntax::codemap::{dummy_spanned, respan};
47 use syntax::ext::hygiene::{Mark, SyntaxContext};
48 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
49 use syntax::ext::base::SyntaxExtension;
50 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
51 use syntax::ext::base::MacroKind;
52 use syntax::symbol::{Symbol, keywords};
53 use syntax::util::lev_distance::find_best_match_for_name;
55 use syntax::visit::{self, FnKind, Visitor};
57 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
58 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
59 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
60 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
61 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
62 use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
64 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
65 use errors::DiagnosticBuilder;
67 use std::cell::{Cell, RefCell};
69 use std::collections::BTreeSet;
71 use std::mem::replace;
74 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
75 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
77 // NB: This module needs to be declared first so diagnostics are
78 // registered before they are used.
83 mod build_reduced_graph;
86 /// A free importable items suggested in case of resolution failure.
87 struct ImportSuggestion {
91 /// A field or associated item from self type suggested in case of resolution failure.
92 enum AssocSuggestion {
101 origin: BTreeSet<Span>,
102 target: BTreeSet<Span>,
105 impl PartialOrd for BindingError {
106 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
107 Some(self.cmp(other))
111 impl PartialEq for BindingError {
112 fn eq(&self, other: &BindingError) -> bool {
113 self.name == other.name
117 impl Ord for BindingError {
118 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
119 self.name.cmp(&other.name)
123 enum ResolutionError<'a> {
124 /// error E0401: can't use type parameters from outer function
125 TypeParametersFromOuterFunction,
126 /// error E0403: the name is already used for a type parameter in this type parameter list
127 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
128 /// error E0407: method is not a member of trait
129 MethodNotMemberOfTrait(Name, &'a str),
130 /// error E0437: type is not a member of trait
131 TypeNotMemberOfTrait(Name, &'a str),
132 /// error E0438: const is not a member of trait
133 ConstNotMemberOfTrait(Name, &'a str),
134 /// error E0408: variable `{}` is not bound in all patterns
135 VariableNotBoundInPattern(&'a BindingError),
136 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
137 VariableBoundWithDifferentMode(Name, Span),
138 /// error E0415: identifier is bound more than once in this parameter list
139 IdentifierBoundMoreThanOnceInParameterList(&'a str),
140 /// error E0416: identifier is bound more than once in the same pattern
141 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
142 /// error E0426: use of undeclared label
143 UndeclaredLabel(&'a str),
144 /// error E0429: `self` imports are only allowed within a { } list
145 SelfImportsOnlyAllowedWithin,
146 /// error E0430: `self` import can only appear once in the list
147 SelfImportCanOnlyAppearOnceInTheList,
148 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
149 SelfImportOnlyInImportListWithNonEmptyPrefix,
150 /// error E0432: unresolved import
151 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
152 /// error E0433: failed to resolve
153 FailedToResolve(&'a str),
154 /// error E0434: can't capture dynamic environment in a fn item
155 CannotCaptureDynamicEnvironmentInFnItem,
156 /// error E0435: attempt to use a non-constant value in a constant
157 AttemptToUseNonConstantValueInConstant,
158 /// error E0530: X bindings cannot shadow Ys
159 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
160 /// error E0128: type parameters with a default cannot use forward declared identifiers
161 ForwardDeclaredTyParam,
164 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
166 resolution_error: ResolutionError<'a>) {
167 resolve_struct_error(resolver, span, resolution_error).emit();
170 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
172 resolution_error: ResolutionError<'a>)
173 -> DiagnosticBuilder<'sess> {
174 match resolution_error {
175 ResolutionError::TypeParametersFromOuterFunction => {
176 let mut err = struct_span_err!(resolver.session,
179 "can't use type parameters from outer function; \
180 try using a local type parameter instead");
181 err.span_label(span, "use of type variable from outer function");
184 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
185 let mut err = struct_span_err!(resolver.session,
188 "the name `{}` is already used for a type parameter \
189 in this type parameter list",
191 err.span_label(span, "already used");
192 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
195 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
196 let mut err = struct_span_err!(resolver.session,
199 "method `{}` is not a member of trait `{}`",
202 err.span_label(span, format!("not a member of trait `{}`", trait_));
205 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
206 let mut err = struct_span_err!(resolver.session,
209 "type `{}` is not a member of trait `{}`",
212 err.span_label(span, format!("not a member of trait `{}`", trait_));
215 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
216 let mut err = struct_span_err!(resolver.session,
219 "const `{}` is not a member of trait `{}`",
222 err.span_label(span, format!("not a member of trait `{}`", trait_));
225 ResolutionError::VariableNotBoundInPattern(binding_error) => {
226 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
227 let msp = MultiSpan::from_spans(target_sp.clone());
228 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
229 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
230 for sp in target_sp {
231 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
233 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
234 for sp in origin_sp {
235 err.span_label(sp, "variable not in all patterns");
239 ResolutionError::VariableBoundWithDifferentMode(variable_name,
240 first_binding_span) => {
241 let mut err = struct_span_err!(resolver.session,
244 "variable `{}` is bound in inconsistent \
245 ways within the same match arm",
247 err.span_label(span, "bound in different ways");
248 err.span_label(first_binding_span, "first binding");
251 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
252 let mut err = struct_span_err!(resolver.session,
255 "identifier `{}` is bound more than once in this parameter list",
257 err.span_label(span, "used as parameter more than once");
260 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
261 let mut err = struct_span_err!(resolver.session,
264 "identifier `{}` is bound more than once in the same pattern",
266 err.span_label(span, "used in a pattern more than once");
269 ResolutionError::UndeclaredLabel(name) => {
270 let mut err = struct_span_err!(resolver.session,
273 "use of undeclared label `{}`",
275 err.span_label(span, format!("undeclared label `{}`", name));
278 ResolutionError::SelfImportsOnlyAllowedWithin => {
279 struct_span_err!(resolver.session,
283 "`self` imports are only allowed within a { } list")
285 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
286 struct_span_err!(resolver.session,
289 "`self` import can only appear once in the list")
291 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
292 struct_span_err!(resolver.session,
295 "`self` import can only appear in an import list with a \
298 ResolutionError::UnresolvedImport(name) => {
299 let (span, msg) = match name {
300 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
301 None => (span, "unresolved import".to_owned()),
303 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
304 if let Some((_, _, p)) = name {
305 err.span_label(span, p);
309 ResolutionError::FailedToResolve(msg) => {
310 let mut err = struct_span_err!(resolver.session, span, E0433,
311 "failed to resolve. {}", msg);
312 err.span_label(span, msg);
315 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
316 struct_span_err!(resolver.session,
320 "can't capture dynamic environment in a fn item; use the || { ... } \
321 closure form instead")
323 ResolutionError::AttemptToUseNonConstantValueInConstant => {
324 let mut err = struct_span_err!(resolver.session,
327 "attempt to use a non-constant value in a constant");
328 err.span_label(span, "non-constant value");
331 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
332 let shadows_what = PathResolution::new(binding.def()).kind_name();
333 let mut err = struct_span_err!(resolver.session,
336 "{}s cannot shadow {}s", what_binding, shadows_what);
337 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
338 let participle = if binding.is_import() { "imported" } else { "defined" };
339 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
340 err.span_label(binding.span, msg);
343 ResolutionError::ForwardDeclaredTyParam => {
344 let mut err = struct_span_err!(resolver.session, span, E0128,
345 "type parameters with a default cannot use \
346 forward declared identifiers");
347 err.span_label(span, format!("defaulted type parameters \
348 cannot be forward declared"));
354 #[derive(Copy, Clone, Debug)]
357 binding_mode: BindingMode,
360 // Map from the name in a pattern to its binding mode.
361 type BindingMap = FxHashMap<Ident, BindingInfo>;
363 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
374 fn is_refutable(self) -> bool {
376 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
377 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
380 fn descr(self) -> &'static str {
382 PatternSource::Match => "match binding",
383 PatternSource::IfLet => "if let binding",
384 PatternSource::WhileLet => "while let binding",
385 PatternSource::Let => "let binding",
386 PatternSource::For => "for binding",
387 PatternSource::FnParam => "function parameter",
392 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
393 enum PathSource<'a> {
394 // Type paths `Path`.
396 // Trait paths in bounds or impls.
398 // Expression paths `path`, with optional parent context.
399 Expr(Option<&'a Expr>),
400 // Paths in path patterns `Path`.
402 // Paths in struct expressions and patterns `Path { .. }`.
404 // Paths in tuple struct patterns `Path(..)`.
406 // `m::A::B` in `<T as m::A>::B::C`.
407 TraitItem(Namespace),
408 // Path in `pub(path)`
410 // Path in `use a::b::{...};`
414 impl<'a> PathSource<'a> {
415 fn namespace(self) -> Namespace {
417 PathSource::Type | PathSource::Trait | PathSource::Struct |
418 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
419 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
420 PathSource::TraitItem(ns) => ns,
424 fn global_by_default(self) -> bool {
426 PathSource::Visibility | PathSource::ImportPrefix => true,
427 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
428 PathSource::Struct | PathSource::TupleStruct |
429 PathSource::Trait | PathSource::TraitItem(..) => false,
433 fn defer_to_typeck(self) -> bool {
435 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
436 PathSource::Struct | PathSource::TupleStruct => true,
437 PathSource::Trait | PathSource::TraitItem(..) |
438 PathSource::Visibility | PathSource::ImportPrefix => false,
442 fn descr_expected(self) -> &'static str {
444 PathSource::Type => "type",
445 PathSource::Trait => "trait",
446 PathSource::Pat => "unit struct/variant or constant",
447 PathSource::Struct => "struct, variant or union type",
448 PathSource::TupleStruct => "tuple struct/variant",
449 PathSource::Visibility => "module",
450 PathSource::ImportPrefix => "module or enum",
451 PathSource::TraitItem(ns) => match ns {
452 TypeNS => "associated type",
453 ValueNS => "method or associated constant",
454 MacroNS => bug!("associated macro"),
456 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
457 // "function" here means "anything callable" rather than `Def::Fn`,
458 // this is not precise but usually more helpful than just "value".
459 Some(&ExprKind::Call(..)) => "function",
465 fn is_expected(self, def: Def) -> bool {
467 PathSource::Type => match def {
468 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
469 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
470 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
473 PathSource::Trait => match def {
474 Def::Trait(..) => true,
477 PathSource::Expr(..) => match def {
478 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
479 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
480 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
481 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
484 PathSource::Pat => match def {
485 Def::StructCtor(_, CtorKind::Const) |
486 Def::VariantCtor(_, CtorKind::Const) |
487 Def::Const(..) | Def::AssociatedConst(..) => true,
490 PathSource::TupleStruct => match def {
491 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
494 PathSource::Struct => match def {
495 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
496 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
499 PathSource::TraitItem(ns) => match def {
500 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
501 Def::AssociatedTy(..) if ns == TypeNS => true,
504 PathSource::ImportPrefix => match def {
505 Def::Mod(..) | Def::Enum(..) => true,
508 PathSource::Visibility => match def {
509 Def::Mod(..) => true,
515 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
516 __diagnostic_used!(E0404);
517 __diagnostic_used!(E0405);
518 __diagnostic_used!(E0412);
519 __diagnostic_used!(E0422);
520 __diagnostic_used!(E0423);
521 __diagnostic_used!(E0425);
522 __diagnostic_used!(E0531);
523 __diagnostic_used!(E0532);
524 __diagnostic_used!(E0573);
525 __diagnostic_used!(E0574);
526 __diagnostic_used!(E0575);
527 __diagnostic_used!(E0576);
528 __diagnostic_used!(E0577);
529 __diagnostic_used!(E0578);
530 match (self, has_unexpected_resolution) {
531 (PathSource::Trait, true) => "E0404",
532 (PathSource::Trait, false) => "E0405",
533 (PathSource::Type, true) => "E0573",
534 (PathSource::Type, false) => "E0412",
535 (PathSource::Struct, true) => "E0574",
536 (PathSource::Struct, false) => "E0422",
537 (PathSource::Expr(..), true) => "E0423",
538 (PathSource::Expr(..), false) => "E0425",
539 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
540 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
541 (PathSource::TraitItem(..), true) => "E0575",
542 (PathSource::TraitItem(..), false) => "E0576",
543 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
544 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
549 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
556 #[derive(Clone, Default, Debug)]
557 pub struct PerNS<T> {
563 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
565 fn index(&self, ns: Namespace) -> &T {
567 ValueNS => &self.value_ns,
568 TypeNS => &self.type_ns,
569 MacroNS => self.macro_ns.as_ref().unwrap(),
574 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
575 fn index_mut(&mut self, ns: Namespace) -> &mut T {
577 ValueNS => &mut self.value_ns,
578 TypeNS => &mut self.type_ns,
579 MacroNS => self.macro_ns.as_mut().unwrap(),
584 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
585 fn visit_item(&mut self, item: &'tcx Item) {
586 self.resolve_item(item);
588 fn visit_arm(&mut self, arm: &'tcx Arm) {
589 self.resolve_arm(arm);
591 fn visit_block(&mut self, block: &'tcx Block) {
592 self.resolve_block(block);
594 fn visit_expr(&mut self, expr: &'tcx Expr) {
595 self.resolve_expr(expr, None);
597 fn visit_local(&mut self, local: &'tcx Local) {
598 self.resolve_local(local);
600 fn visit_ty(&mut self, ty: &'tcx Ty) {
602 TyKind::Path(ref qself, ref path) => {
603 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
605 TyKind::ImplicitSelf => {
606 let self_ty = keywords::SelfType.ident();
607 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
608 .map_or(Def::Err, |d| d.def());
609 self.record_def(ty.id, PathResolution::new(def));
611 TyKind::Array(ref element, ref length) => {
612 self.visit_ty(element);
613 self.with_constant_rib(|this| {
614 this.visit_expr(length);
620 visit::walk_ty(self, ty);
622 fn visit_poly_trait_ref(&mut self,
623 tref: &'tcx ast::PolyTraitRef,
624 m: &'tcx ast::TraitBoundModifier) {
625 self.smart_resolve_path(tref.trait_ref.ref_id, None,
626 &tref.trait_ref.path, PathSource::Trait);
627 visit::walk_poly_trait_ref(self, tref, m);
629 fn visit_variant(&mut self,
630 variant: &'tcx ast::Variant,
631 generics: &'tcx Generics,
632 item_id: ast::NodeId) {
633 if let Some(ref dis_expr) = variant.node.disr_expr {
634 // resolve the discriminator expr as a constant
635 self.with_constant_rib(|this| {
636 this.visit_expr(dis_expr);
640 // `visit::walk_variant` without the discriminant expression.
641 self.visit_variant_data(&variant.node.data,
647 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
648 let type_parameters = match foreign_item.node {
649 ForeignItemKind::Fn(_, ref generics) => {
650 HasTypeParameters(generics, ItemRibKind)
652 ForeignItemKind::Static(..) => NoTypeParameters,
654 self.with_type_parameter_rib(type_parameters, |this| {
655 visit::walk_foreign_item(this, foreign_item);
658 fn visit_fn(&mut self,
659 function_kind: FnKind<'tcx>,
660 declaration: &'tcx FnDecl,
663 let rib_kind = match function_kind {
664 FnKind::ItemFn(_, generics, ..) => {
665 self.visit_generics(generics);
668 FnKind::Method(_, sig, _, _) => {
669 self.visit_generics(&sig.generics);
670 MethodRibKind(!sig.decl.has_self())
672 FnKind::Closure(_) => ClosureRibKind(node_id),
675 // Create a value rib for the function.
676 self.ribs[ValueNS].push(Rib::new(rib_kind));
678 // Create a label rib for the function.
679 self.label_ribs.push(Rib::new(rib_kind));
681 // Add each argument to the rib.
682 let mut bindings_list = FxHashMap();
683 for argument in &declaration.inputs {
684 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
686 self.visit_ty(&argument.ty);
688 debug!("(resolving function) recorded argument");
690 visit::walk_fn_ret_ty(self, &declaration.output);
692 // Resolve the function body.
693 match function_kind {
694 FnKind::ItemFn(.., body) |
695 FnKind::Method(.., body) => {
696 self.visit_block(body);
698 FnKind::Closure(body) => {
699 self.visit_expr(body);
703 debug!("(resolving function) leaving function");
705 self.label_ribs.pop();
706 self.ribs[ValueNS].pop();
708 fn visit_generics(&mut self, generics: &'tcx Generics) {
709 // For type parameter defaults, we have to ban access
710 // to following type parameters, as the Substs can only
711 // provide previous type parameters as they're built.
712 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
713 default_ban_rib.bindings.extend(generics.ty_params.iter()
714 .skip_while(|p| p.default.is_none())
715 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
717 for param in &generics.ty_params {
718 for bound in ¶m.bounds {
719 self.visit_ty_param_bound(bound);
722 if let Some(ref ty) = param.default {
723 self.ribs[TypeNS].push(default_ban_rib);
725 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
728 // Allow all following defaults to refer to this type parameter.
729 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
731 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
732 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
736 pub type ErrorMessage = Option<(Span, String)>;
738 #[derive(Copy, Clone)]
739 enum TypeParameters<'a, 'b> {
741 HasTypeParameters(// Type parameters.
744 // The kind of the rib used for type parameters.
748 // The rib kind controls the translation of local
749 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
750 #[derive(Copy, Clone, Debug)]
752 // No translation needs to be applied.
755 // We passed through a closure scope at the given node ID.
756 // Translate upvars as appropriate.
757 ClosureRibKind(NodeId /* func id */),
759 // We passed through an impl or trait and are now in one of its
760 // methods. Allow references to ty params that impl or trait
761 // binds. Disallow any other upvars (including other ty params that are
764 // The boolean value represents the fact that this method is static or not.
767 // We passed through an item scope. Disallow upvars.
770 // We're in a constant item. Can't refer to dynamic stuff.
773 // We passed through a module.
774 ModuleRibKind(Module<'a>),
776 // We passed through a `macro_rules!` statement
777 MacroDefinition(DefId),
779 // All bindings in this rib are type parameters that can't be used
780 // from the default of a type parameter because they're not declared
781 // before said type parameter. Also see the `visit_generics` override.
782 ForwardTyParamBanRibKind,
788 bindings: FxHashMap<Ident, Def>,
793 fn new(kind: RibKind<'a>) -> Rib<'a> {
795 bindings: FxHashMap(),
801 enum LexicalScopeBinding<'a> {
802 Item(&'a NameBinding<'a>),
806 impl<'a> LexicalScopeBinding<'a> {
807 fn item(self) -> Option<&'a NameBinding<'a>> {
809 LexicalScopeBinding::Item(binding) => Some(binding),
814 fn def(self) -> Def {
816 LexicalScopeBinding::Item(binding) => binding.def(),
817 LexicalScopeBinding::Def(def) => def,
823 enum PathResult<'a> {
825 NonModule(PathResolution),
827 Failed(Span, String, bool /* is the error from the last segment? */),
835 /// One node in the tree of modules.
836 pub struct ModuleData<'a> {
837 parent: Option<Module<'a>>,
840 // The def id of the closest normal module (`mod`) ancestor (including this module).
841 normal_ancestor_id: DefId,
843 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
844 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
845 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
847 // Macro invocations that can expand into items in this module.
848 unresolved_invocations: RefCell<FxHashSet<Mark>>,
850 no_implicit_prelude: bool,
852 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
853 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
855 // Used to memoize the traits in this module for faster searches through all traits in scope.
856 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
858 // Whether this module is populated. If not populated, any attempt to
859 // access the children must be preceded with a
860 // `populate_module_if_necessary` call.
861 populated: Cell<bool>,
863 /// Span of the module itself. Used for error reporting.
869 pub type Module<'a> = &'a ModuleData<'a>;
871 impl<'a> ModuleData<'a> {
872 fn new(parent: Option<Module<'a>>,
874 normal_ancestor_id: DefId,
876 span: Span) -> Self {
880 normal_ancestor_id: normal_ancestor_id,
881 resolutions: RefCell::new(FxHashMap()),
882 legacy_macro_resolutions: RefCell::new(Vec::new()),
883 macro_resolutions: RefCell::new(Vec::new()),
884 unresolved_invocations: RefCell::new(FxHashSet()),
885 no_implicit_prelude: false,
886 glob_importers: RefCell::new(Vec::new()),
887 globs: RefCell::new((Vec::new())),
888 traits: RefCell::new(None),
889 populated: Cell::new(normal_ancestor_id.is_local()),
891 expansion: expansion,
895 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
896 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
897 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
901 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
902 let resolutions = self.resolutions.borrow();
903 let mut resolutions = resolutions.iter().map(|(&(ident, ns), &resolution)| {
904 // Pre-compute keys for sorting
905 (ident.name.as_str(), ns, ident, resolution)
907 .collect::<Vec<_>>();
908 resolutions.sort_unstable_by_key(|&(str, ns, ..)| (str, ns));
909 for &(_, ns, ident, resolution) in resolutions.iter() {
910 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
914 fn def(&self) -> Option<Def> {
916 ModuleKind::Def(def, _) => Some(def),
921 fn def_id(&self) -> Option<DefId> {
922 self.def().as_ref().map(Def::def_id)
925 // `self` resolves to the first module ancestor that `is_normal`.
926 fn is_normal(&self) -> bool {
928 ModuleKind::Def(Def::Mod(_), _) => true,
933 fn is_trait(&self) -> bool {
935 ModuleKind::Def(Def::Trait(_), _) => true,
940 fn is_local(&self) -> bool {
941 self.normal_ancestor_id.is_local()
944 fn nearest_item_scope(&'a self) -> Module<'a> {
945 if self.is_trait() { self.parent.unwrap() } else { self }
949 impl<'a> fmt::Debug for ModuleData<'a> {
950 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
951 write!(f, "{:?}", self.def())
955 // Records a possibly-private value, type, or module definition.
956 #[derive(Clone, Debug)]
957 pub struct NameBinding<'a> {
958 kind: NameBindingKind<'a>,
964 pub trait ToNameBinding<'a> {
965 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
968 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
969 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
974 #[derive(Clone, Debug)]
975 enum NameBindingKind<'a> {
979 binding: &'a NameBinding<'a>,
980 directive: &'a ImportDirective<'a>,
982 legacy_self_import: bool,
985 b1: &'a NameBinding<'a>,
986 b2: &'a NameBinding<'a>,
991 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
993 struct AmbiguityError<'a> {
997 b1: &'a NameBinding<'a>,
998 b2: &'a NameBinding<'a>,
1002 impl<'a> NameBinding<'a> {
1003 fn module(&self) -> Option<Module<'a>> {
1005 NameBindingKind::Module(module) => Some(module),
1006 NameBindingKind::Import { binding, .. } => binding.module(),
1007 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1012 fn def(&self) -> Def {
1014 NameBindingKind::Def(def) => def,
1015 NameBindingKind::Module(module) => module.def().unwrap(),
1016 NameBindingKind::Import { binding, .. } => binding.def(),
1017 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1018 NameBindingKind::Ambiguity { .. } => Def::Err,
1022 fn def_ignoring_ambiguity(&self) -> Def {
1024 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1025 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1030 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
1031 resolver.get_macro(self.def_ignoring_ambiguity())
1034 // We sometimes need to treat variants as `pub` for backwards compatibility
1035 fn pseudo_vis(&self) -> ty::Visibility {
1036 if self.is_variant() { ty::Visibility::Public } else { self.vis }
1039 fn is_variant(&self) -> bool {
1041 NameBindingKind::Def(Def::Variant(..)) |
1042 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1047 fn is_extern_crate(&self) -> bool {
1049 NameBindingKind::Import {
1050 directive: &ImportDirective {
1051 subclass: ImportDirectiveSubclass::ExternCrate, ..
1058 fn is_import(&self) -> bool {
1060 NameBindingKind::Import { .. } => true,
1065 fn is_glob_import(&self) -> bool {
1067 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1068 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1073 fn is_importable(&self) -> bool {
1075 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1080 fn is_macro_def(&self) -> bool {
1082 NameBindingKind::Def(Def::Macro(..)) => true,
1087 fn descr(&self) -> &'static str {
1088 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1092 /// Interns the names of the primitive types.
1093 struct PrimitiveTypeTable {
1094 primitive_types: FxHashMap<Name, PrimTy>,
1097 impl PrimitiveTypeTable {
1098 fn new() -> PrimitiveTypeTable {
1099 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1101 table.intern("bool", TyBool);
1102 table.intern("char", TyChar);
1103 table.intern("f32", TyFloat(FloatTy::F32));
1104 table.intern("f64", TyFloat(FloatTy::F64));
1105 table.intern("isize", TyInt(IntTy::Is));
1106 table.intern("i8", TyInt(IntTy::I8));
1107 table.intern("i16", TyInt(IntTy::I16));
1108 table.intern("i32", TyInt(IntTy::I32));
1109 table.intern("i64", TyInt(IntTy::I64));
1110 table.intern("i128", TyInt(IntTy::I128));
1111 table.intern("str", TyStr);
1112 table.intern("usize", TyUint(UintTy::Us));
1113 table.intern("u8", TyUint(UintTy::U8));
1114 table.intern("u16", TyUint(UintTy::U16));
1115 table.intern("u32", TyUint(UintTy::U32));
1116 table.intern("u64", TyUint(UintTy::U64));
1117 table.intern("u128", TyUint(UintTy::U128));
1121 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1122 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1126 /// The main resolver class.
1127 pub struct Resolver<'a> {
1128 session: &'a Session,
1130 pub definitions: Definitions,
1132 graph_root: Module<'a>,
1134 prelude: Option<Module<'a>>,
1136 // n.b. This is used only for better diagnostics, not name resolution itself.
1137 has_self: FxHashSet<DefId>,
1139 // Names of fields of an item `DefId` accessible with dot syntax.
1140 // Used for hints during error reporting.
1141 field_names: FxHashMap<DefId, Vec<Name>>,
1143 // All imports known to succeed or fail.
1144 determined_imports: Vec<&'a ImportDirective<'a>>,
1146 // All non-determined imports.
1147 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1149 // The module that represents the current item scope.
1150 current_module: Module<'a>,
1152 // The current set of local scopes for types and values.
1153 // FIXME #4948: Reuse ribs to avoid allocation.
1154 ribs: PerNS<Vec<Rib<'a>>>,
1156 // The current set of local scopes, for labels.
1157 label_ribs: Vec<Rib<'a>>,
1159 // The trait that the current context can refer to.
1160 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1162 // The current self type if inside an impl (used for better errors).
1163 current_self_type: Option<Ty>,
1165 // The idents for the primitive types.
1166 primitive_type_table: PrimitiveTypeTable,
1169 pub freevars: FreevarMap,
1170 freevars_seen: NodeMap<NodeMap<usize>>,
1171 pub export_map: ExportMap,
1172 pub trait_map: TraitMap,
1174 // A map from nodes to anonymous modules.
1175 // Anonymous modules are pseudo-modules that are implicitly created around items
1176 // contained within blocks.
1178 // For example, if we have this:
1186 // There will be an anonymous module created around `g` with the ID of the
1187 // entry block for `f`.
1188 block_map: NodeMap<Module<'a>>,
1189 module_map: FxHashMap<DefId, Module<'a>>,
1190 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1192 pub make_glob_map: bool,
1193 // Maps imports to the names of items actually imported (this actually maps
1194 // all imports, but only glob imports are actually interesting).
1195 pub glob_map: GlobMap,
1197 used_imports: FxHashSet<(NodeId, Namespace)>,
1198 pub maybe_unused_trait_imports: NodeSet,
1200 privacy_errors: Vec<PrivacyError<'a>>,
1201 ambiguity_errors: Vec<AmbiguityError<'a>>,
1202 gated_errors: FxHashSet<Span>,
1203 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1205 arenas: &'a ResolverArenas<'a>,
1206 dummy_binding: &'a NameBinding<'a>,
1207 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1209 crate_loader: &'a mut CrateLoader,
1210 macro_names: FxHashSet<Ident>,
1211 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1212 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1213 macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
1214 macro_defs: FxHashMap<Mark, DefId>,
1215 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1216 macro_exports: Vec<Export>,
1217 pub whitelisted_legacy_custom_derives: Vec<Name>,
1218 pub found_unresolved_macro: bool,
1220 // List of crate local macros that we need to warn about as being unused.
1221 // Right now this only includes macro_rules! macros, and macros 2.0.
1222 unused_macros: FxHashSet<DefId>,
1224 // Maps the `Mark` of an expansion to its containing module or block.
1225 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1227 // Avoid duplicated errors for "name already defined".
1228 name_already_seen: FxHashMap<Name, Span>,
1230 // If `#![feature(proc_macro)]` is set
1231 proc_macro_enabled: bool,
1233 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1234 warned_proc_macros: FxHashSet<Name>,
1236 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1238 // This table maps struct IDs into struct constructor IDs,
1239 // it's not used during normal resolution, only for better error reporting.
1240 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1242 // Only used for better errors on `fn(): fn()`
1243 current_type_ascription: Vec<Span>,
1246 pub struct ResolverArenas<'a> {
1247 modules: arena::TypedArena<ModuleData<'a>>,
1248 local_modules: RefCell<Vec<Module<'a>>>,
1249 name_bindings: arena::TypedArena<NameBinding<'a>>,
1250 import_directives: arena::TypedArena<ImportDirective<'a>>,
1251 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1252 invocation_data: arena::TypedArena<InvocationData<'a>>,
1253 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1256 impl<'a> ResolverArenas<'a> {
1257 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1258 let module = self.modules.alloc(module);
1259 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1260 self.local_modules.borrow_mut().push(module);
1264 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1265 self.local_modules.borrow()
1267 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1268 self.name_bindings.alloc(name_binding)
1270 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1271 -> &'a ImportDirective {
1272 self.import_directives.alloc(import_directive)
1274 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1275 self.name_resolutions.alloc(Default::default())
1277 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1278 -> &'a InvocationData<'a> {
1279 self.invocation_data.alloc(expansion_data)
1281 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1282 self.legacy_bindings.alloc(binding)
1286 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1287 fn parent(self, id: DefId) -> Option<DefId> {
1289 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1290 _ => self.session.cstore.def_key(id).parent,
1291 }.map(|index| DefId { index: index, ..id })
1295 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1296 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1297 let namespace = if is_value { ValueNS } else { TypeNS };
1298 let hir::Path { ref segments, span, ref mut def } = *path;
1299 let path: Vec<SpannedIdent> = segments.iter()
1300 .map(|seg| respan(span, Ident::with_empty_ctxt(seg.name)))
1302 match self.resolve_path(&path, Some(namespace), true, span) {
1303 PathResult::Module(module) => *def = module.def().unwrap(),
1304 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1305 *def = path_res.base_def(),
1306 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1307 PathResult::Failed(span, msg, _) => {
1308 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1312 PathResult::Indeterminate => unreachable!(),
1313 PathResult::Failed(span, msg, _) => {
1314 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1319 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1320 self.def_map.get(&id).cloned()
1323 fn definitions(&mut self) -> &mut Definitions {
1324 &mut self.definitions
1328 impl<'a> Resolver<'a> {
1329 pub fn new(session: &'a Session,
1332 make_glob_map: MakeGlobMap,
1333 crate_loader: &'a mut CrateLoader,
1334 arenas: &'a ResolverArenas<'a>)
1336 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1337 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1338 let graph_root = arenas.alloc_module(ModuleData {
1339 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1340 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1342 let mut module_map = FxHashMap();
1343 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1345 let mut definitions = Definitions::new();
1346 DefCollector::new(&mut definitions, Mark::root())
1347 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1349 let mut invocations = FxHashMap();
1350 invocations.insert(Mark::root(),
1351 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1353 let features = session.features.borrow();
1355 let mut macro_defs = FxHashMap();
1356 macro_defs.insert(Mark::root(), root_def_id);
1361 definitions: definitions,
1363 // The outermost module has def ID 0; this is not reflected in the
1365 graph_root: graph_root,
1368 has_self: FxHashSet(),
1369 field_names: FxHashMap(),
1371 determined_imports: Vec::new(),
1372 indeterminate_imports: Vec::new(),
1374 current_module: graph_root,
1376 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1377 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1378 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1380 label_ribs: Vec::new(),
1382 current_trait_ref: None,
1383 current_self_type: None,
1385 primitive_type_table: PrimitiveTypeTable::new(),
1388 freevars: NodeMap(),
1389 freevars_seen: NodeMap(),
1390 export_map: NodeMap(),
1391 trait_map: NodeMap(),
1392 module_map: module_map,
1393 block_map: NodeMap(),
1394 extern_module_map: FxHashMap(),
1396 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1397 glob_map: NodeMap(),
1399 used_imports: FxHashSet(),
1400 maybe_unused_trait_imports: NodeSet(),
1402 privacy_errors: Vec::new(),
1403 ambiguity_errors: Vec::new(),
1404 gated_errors: FxHashSet(),
1405 disallowed_shadowing: Vec::new(),
1408 dummy_binding: arenas.alloc_name_binding(NameBinding {
1409 kind: NameBindingKind::Def(Def::Err),
1410 expansion: Mark::root(),
1412 vis: ty::Visibility::Public,
1415 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1417 features.use_extern_macros || features.proc_macro || features.decl_macro,
1419 crate_loader: crate_loader,
1420 macro_names: FxHashSet(),
1421 global_macros: FxHashMap(),
1422 lexical_macro_resolutions: Vec::new(),
1423 macro_map: FxHashMap(),
1424 macro_exports: Vec::new(),
1425 invocations: invocations,
1426 macro_defs: macro_defs,
1427 local_macro_def_scopes: FxHashMap(),
1428 name_already_seen: FxHashMap(),
1429 whitelisted_legacy_custom_derives: Vec::new(),
1430 proc_macro_enabled: features.proc_macro,
1431 warned_proc_macros: FxHashSet(),
1432 potentially_unused_imports: Vec::new(),
1433 struct_constructors: DefIdMap(),
1434 found_unresolved_macro: false,
1435 unused_macros: FxHashSet(),
1436 current_type_ascription: Vec::new(),
1440 pub fn arenas() -> ResolverArenas<'a> {
1442 modules: arena::TypedArena::new(),
1443 local_modules: RefCell::new(Vec::new()),
1444 name_bindings: arena::TypedArena::new(),
1445 import_directives: arena::TypedArena::new(),
1446 name_resolutions: arena::TypedArena::new(),
1447 invocation_data: arena::TypedArena::new(),
1448 legacy_bindings: arena::TypedArena::new(),
1452 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1454 type_ns: f(self, TypeNS),
1455 value_ns: f(self, ValueNS),
1456 macro_ns: match self.use_extern_macros {
1457 true => Some(f(self, MacroNS)),
1463 /// Entry point to crate resolution.
1464 pub fn resolve_crate(&mut self, krate: &Crate) {
1465 ImportResolver { resolver: self }.finalize_imports();
1466 self.current_module = self.graph_root;
1467 self.finalize_current_module_macro_resolutions();
1468 visit::walk_crate(self, krate);
1470 check_unused::check_crate(self, krate);
1471 self.report_errors();
1472 self.crate_loader.postprocess(krate);
1479 normal_ancestor_id: DefId,
1483 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1484 self.arenas.alloc_module(module)
1487 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1488 -> bool /* true if an error was reported */ {
1489 match binding.kind {
1490 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1493 directive.used.set(true);
1494 if legacy_self_import {
1495 self.warn_legacy_self_import(directive);
1498 self.used_imports.insert((directive.id, ns));
1499 self.add_to_glob_map(directive.id, ident);
1500 self.record_use(ident, ns, binding, span)
1502 NameBindingKind::Import { .. } => false,
1503 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1504 self.ambiguity_errors.push(AmbiguityError {
1505 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
1508 self.record_use(ident, ns, b1, span);
1516 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1517 if self.make_glob_map {
1518 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1522 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1523 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1524 /// `ident` in the first scope that defines it (or None if no scopes define it).
1526 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1527 /// the items are defined in the block. For example,
1530 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1533 /// g(); // This resolves to the local variable `g` since it shadows the item.
1537 /// Invariant: This must only be called during main resolution, not during
1538 /// import resolution.
1539 fn resolve_ident_in_lexical_scope(&mut self,
1544 -> Option<LexicalScopeBinding<'a>> {
1546 ident.ctxt = if ident.name == keywords::SelfType.name() {
1547 SyntaxContext::empty() // FIXME(jseyfried) improve `Self` hygiene
1553 // Walk backwards up the ribs in scope.
1554 let mut module = self.graph_root;
1555 for i in (0 .. self.ribs[ns].len()).rev() {
1556 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1557 // The ident resolves to a type parameter or local variable.
1558 return Some(LexicalScopeBinding::Def(
1559 self.adjust_local_def(ns, i, def, record_used, path_span)
1563 module = match self.ribs[ns][i].kind {
1564 ModuleRibKind(module) => module,
1565 MacroDefinition(def) if def == self.macro_defs[&ident.ctxt.outer()] => {
1566 // If an invocation of this macro created `ident`, give up on `ident`
1567 // and switch to `ident`'s source from the macro definition.
1568 ident.ctxt.remove_mark();
1574 let item = self.resolve_ident_in_module_unadjusted(
1575 module, ident, ns, false, record_used, path_span,
1577 if let Ok(binding) = item {
1578 // The ident resolves to an item.
1579 return Some(LexicalScopeBinding::Item(binding));
1583 ModuleKind::Block(..) => {}, // We can see through blocks
1588 ident.ctxt = ident.ctxt.modern();
1590 module = unwrap_or!(self.hygienic_lexical_parent(module, &mut ident.ctxt), break);
1591 let orig_current_module = self.current_module;
1592 self.current_module = module; // Lexical resolutions can never be a privacy error.
1593 let result = self.resolve_ident_in_module_unadjusted(
1594 module, ident, ns, false, record_used, path_span,
1596 self.current_module = orig_current_module;
1599 Ok(binding) => return Some(LexicalScopeBinding::Item(binding)),
1600 Err(Undetermined) => return None,
1601 Err(Determined) => {}
1605 match self.prelude {
1606 Some(prelude) if !module.no_implicit_prelude => {
1607 self.resolve_ident_in_module_unadjusted(prelude, ident, ns, false, false, path_span)
1608 .ok().map(LexicalScopeBinding::Item)
1614 fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, ctxt: &mut SyntaxContext)
1615 -> Option<Module<'a>> {
1616 if !module.expansion.is_descendant_of(ctxt.outer()) {
1617 return Some(self.macro_def_scope(ctxt.remove_mark()));
1620 if let ModuleKind::Block(..) = module.kind {
1621 return Some(module.parent.unwrap());
1624 let mut module_expansion = module.expansion.modern(); // for backward compatability
1625 while let Some(parent) = module.parent {
1626 let parent_expansion = parent.expansion.modern();
1627 if module_expansion.is_descendant_of(parent_expansion) &&
1628 parent_expansion != module_expansion {
1629 return if parent_expansion.is_descendant_of(ctxt.outer()) {
1636 module_expansion = parent_expansion;
1642 fn resolve_ident_in_module(&mut self,
1646 ignore_unresolved_invocations: bool,
1649 -> Result<&'a NameBinding<'a>, Determinacy> {
1650 ident.ctxt = ident.ctxt.modern();
1651 let orig_current_module = self.current_module;
1652 if let Some(def) = ident.ctxt.adjust(module.expansion) {
1653 self.current_module = self.macro_def_scope(def);
1655 let result = self.resolve_ident_in_module_unadjusted(
1656 module, ident, ns, ignore_unresolved_invocations, record_used, span,
1658 self.current_module = orig_current_module;
1662 fn resolve_crate_root(&mut self, mut ctxt: SyntaxContext) -> Module<'a> {
1663 let module = match ctxt.adjust(Mark::root()) {
1664 Some(def) => self.macro_def_scope(def),
1665 None => return self.graph_root,
1667 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1670 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1671 let mut module = self.get_module(module.normal_ancestor_id);
1672 while module.span.ctxt.modern() != *ctxt {
1673 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1674 module = self.get_module(parent.normal_ancestor_id);
1681 // We maintain a list of value ribs and type ribs.
1683 // Simultaneously, we keep track of the current position in the module
1684 // graph in the `current_module` pointer. When we go to resolve a name in
1685 // the value or type namespaces, we first look through all the ribs and
1686 // then query the module graph. When we resolve a name in the module
1687 // namespace, we can skip all the ribs (since nested modules are not
1688 // allowed within blocks in Rust) and jump straight to the current module
1691 // Named implementations are handled separately. When we find a method
1692 // call, we consult the module node to find all of the implementations in
1693 // scope. This information is lazily cached in the module node. We then
1694 // generate a fake "implementation scope" containing all the
1695 // implementations thus found, for compatibility with old resolve pass.
1697 fn with_scope<F>(&mut self, id: NodeId, f: F)
1698 where F: FnOnce(&mut Resolver)
1700 let id = self.definitions.local_def_id(id);
1701 let module = self.module_map.get(&id).cloned(); // clones a reference
1702 if let Some(module) = module {
1703 // Move down in the graph.
1704 let orig_module = replace(&mut self.current_module, module);
1705 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1706 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1708 self.finalize_current_module_macro_resolutions();
1711 self.current_module = orig_module;
1712 self.ribs[ValueNS].pop();
1713 self.ribs[TypeNS].pop();
1719 /// Searches the current set of local scopes for labels.
1720 /// Stops after meeting a closure.
1721 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1722 for rib in self.label_ribs.iter().rev() {
1725 // If an invocation of this macro created `ident`, give up on `ident`
1726 // and switch to `ident`'s source from the macro definition.
1727 MacroDefinition(def) => {
1728 if def == self.macro_defs[&ident.ctxt.outer()] {
1729 ident.ctxt.remove_mark();
1733 // Do not resolve labels across function boundary
1737 let result = rib.bindings.get(&ident).cloned();
1738 if result.is_some() {
1745 fn resolve_item(&mut self, item: &Item) {
1746 let name = item.ident.name;
1748 debug!("(resolving item) resolving {}", name);
1750 self.check_proc_macro_attrs(&item.attrs);
1753 ItemKind::Enum(_, ref generics) |
1754 ItemKind::Ty(_, ref generics) |
1755 ItemKind::Struct(_, ref generics) |
1756 ItemKind::Union(_, ref generics) |
1757 ItemKind::Fn(.., ref generics, _) => {
1758 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1759 |this| visit::walk_item(this, item));
1762 ItemKind::DefaultImpl(_, ref trait_ref) => {
1763 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1764 // Resolve type arguments in trait path
1765 visit::walk_trait_ref(this, trait_ref);
1768 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1769 self.resolve_implementation(generics,
1775 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1776 // Create a new rib for the trait-wide type parameters.
1777 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1778 let local_def_id = this.definitions.local_def_id(item.id);
1779 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1780 this.visit_generics(generics);
1781 walk_list!(this, visit_ty_param_bound, bounds);
1783 for trait_item in trait_items {
1784 this.check_proc_macro_attrs(&trait_item.attrs);
1786 match trait_item.node {
1787 TraitItemKind::Const(ref ty, ref default) => {
1790 // Only impose the restrictions of
1791 // ConstRibKind for an actual constant
1792 // expression in a provided default.
1793 if let Some(ref expr) = *default{
1794 this.with_constant_rib(|this| {
1795 this.visit_expr(expr);
1799 TraitItemKind::Method(ref sig, _) => {
1800 let type_parameters =
1801 HasTypeParameters(&sig.generics,
1802 MethodRibKind(!sig.decl.has_self()));
1803 this.with_type_parameter_rib(type_parameters, |this| {
1804 visit::walk_trait_item(this, trait_item)
1807 TraitItemKind::Type(..) => {
1808 this.with_type_parameter_rib(NoTypeParameters, |this| {
1809 visit::walk_trait_item(this, trait_item)
1812 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1819 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1820 self.with_scope(item.id, |this| {
1821 visit::walk_item(this, item);
1825 ItemKind::Static(ref ty, _, ref expr) |
1826 ItemKind::Const(ref ty, ref expr) => {
1827 self.with_item_rib(|this| {
1829 this.with_constant_rib(|this| {
1830 this.visit_expr(expr);
1835 ItemKind::Use(ref view_path) => {
1836 match view_path.node {
1837 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1838 // Resolve prefix of an import with empty braces (issue #28388).
1839 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1845 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1846 // do nothing, these are just around to be encoded
1849 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1853 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1854 where F: FnOnce(&mut Resolver)
1856 match type_parameters {
1857 HasTypeParameters(generics, rib_kind) => {
1858 let mut function_type_rib = Rib::new(rib_kind);
1859 let mut seen_bindings = FxHashMap();
1860 for type_parameter in &generics.ty_params {
1861 let ident = type_parameter.ident.modern();
1862 debug!("with_type_parameter_rib: {}", type_parameter.id);
1864 if seen_bindings.contains_key(&ident) {
1865 let span = seen_bindings.get(&ident).unwrap();
1867 ResolutionError::NameAlreadyUsedInTypeParameterList(ident.name, span);
1868 resolve_error(self, type_parameter.span, err);
1870 seen_bindings.entry(ident).or_insert(type_parameter.span);
1872 // plain insert (no renaming)
1873 let def_id = self.definitions.local_def_id(type_parameter.id);
1874 let def = Def::TyParam(def_id);
1875 function_type_rib.bindings.insert(ident, def);
1876 self.record_def(type_parameter.id, PathResolution::new(def));
1878 self.ribs[TypeNS].push(function_type_rib);
1881 NoTypeParameters => {
1888 if let HasTypeParameters(..) = type_parameters {
1889 self.ribs[TypeNS].pop();
1893 fn with_label_rib<F>(&mut self, f: F)
1894 where F: FnOnce(&mut Resolver)
1896 self.label_ribs.push(Rib::new(NormalRibKind));
1898 self.label_ribs.pop();
1901 fn with_item_rib<F>(&mut self, f: F)
1902 where F: FnOnce(&mut Resolver)
1904 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
1905 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
1907 self.ribs[TypeNS].pop();
1908 self.ribs[ValueNS].pop();
1911 fn with_constant_rib<F>(&mut self, f: F)
1912 where F: FnOnce(&mut Resolver)
1914 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1916 self.ribs[ValueNS].pop();
1919 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1920 where F: FnOnce(&mut Resolver) -> T
1922 // Handle nested impls (inside fn bodies)
1923 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1924 let result = f(self);
1925 self.current_self_type = previous_value;
1929 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1930 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1932 let mut new_val = None;
1933 let mut new_id = None;
1934 if let Some(trait_ref) = opt_trait_ref {
1935 let path: Vec<_> = trait_ref.path.segments.iter()
1936 .map(|seg| respan(seg.span, seg.identifier))
1938 let def = self.smart_resolve_path_fragment(trait_ref.ref_id,
1941 trait_ref.path.span,
1942 trait_ref.path.segments.last().unwrap().span,
1945 if def != Def::Err {
1946 new_id = Some(def.def_id());
1947 let span = trait_ref.path.span;
1948 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span) {
1949 new_val = Some((module, trait_ref.clone()));
1953 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1954 let result = f(self, new_id);
1955 self.current_trait_ref = original_trait_ref;
1959 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1960 where F: FnOnce(&mut Resolver)
1962 let mut self_type_rib = Rib::new(NormalRibKind);
1964 // plain insert (no renaming, types are not currently hygienic....)
1965 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
1966 self.ribs[TypeNS].push(self_type_rib);
1968 self.ribs[TypeNS].pop();
1971 fn resolve_implementation(&mut self,
1972 generics: &Generics,
1973 opt_trait_reference: &Option<TraitRef>,
1976 impl_items: &[ImplItem]) {
1977 // If applicable, create a rib for the type parameters.
1978 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1979 // Dummy self type for better errors if `Self` is used in the trait path.
1980 this.with_self_rib(Def::SelfTy(None, None), |this| {
1981 // Resolve the trait reference, if necessary.
1982 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1983 let item_def_id = this.definitions.local_def_id(item_id);
1984 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
1985 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1986 // Resolve type arguments in trait path
1987 visit::walk_trait_ref(this, trait_ref);
1989 // Resolve the self type.
1990 this.visit_ty(self_type);
1991 // Resolve the type parameters.
1992 this.visit_generics(generics);
1993 this.with_current_self_type(self_type, |this| {
1994 for impl_item in impl_items {
1995 this.check_proc_macro_attrs(&impl_item.attrs);
1996 this.resolve_visibility(&impl_item.vis);
1997 match impl_item.node {
1998 ImplItemKind::Const(..) => {
1999 // If this is a trait impl, ensure the const
2001 this.check_trait_item(impl_item.ident,
2004 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
2005 visit::walk_impl_item(this, impl_item);
2007 ImplItemKind::Method(ref sig, _) => {
2008 // If this is a trait impl, ensure the method
2010 this.check_trait_item(impl_item.ident,
2013 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
2015 // We also need a new scope for the method-
2016 // specific type parameters.
2017 let type_parameters =
2018 HasTypeParameters(&sig.generics,
2019 MethodRibKind(!sig.decl.has_self()));
2020 this.with_type_parameter_rib(type_parameters, |this| {
2021 visit::walk_impl_item(this, impl_item);
2024 ImplItemKind::Type(ref ty) => {
2025 // If this is a trait impl, ensure the type
2027 this.check_trait_item(impl_item.ident,
2030 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
2034 ImplItemKind::Macro(_) =>
2035 panic!("unexpanded macro in resolve!"),
2045 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2046 where F: FnOnce(Name, &str) -> ResolutionError
2048 // If there is a TraitRef in scope for an impl, then the method must be in the
2050 if let Some((module, _)) = self.current_trait_ref {
2051 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2052 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2053 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2058 fn resolve_local(&mut self, local: &Local) {
2059 // Resolve the type.
2060 walk_list!(self, visit_ty, &local.ty);
2062 // Resolve the initializer.
2063 walk_list!(self, visit_expr, &local.init);
2065 // Resolve the pattern.
2066 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2069 // build a map from pattern identifiers to binding-info's.
2070 // this is done hygienically. This could arise for a macro
2071 // that expands into an or-pattern where one 'x' was from the
2072 // user and one 'x' came from the macro.
2073 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2074 let mut binding_map = FxHashMap();
2076 pat.walk(&mut |pat| {
2077 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2078 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2079 Some(Def::Local(..)) => true,
2082 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2083 binding_map.insert(ident.node, binding_info);
2092 // check that all of the arms in an or-pattern have exactly the
2093 // same set of bindings, with the same binding modes for each.
2094 fn check_consistent_bindings(&mut self, arm: &Arm) {
2095 if arm.pats.is_empty() {
2099 let mut missing_vars = FxHashMap();
2100 let mut inconsistent_vars = FxHashMap();
2101 for (i, p) in arm.pats.iter().enumerate() {
2102 let map_i = self.binding_mode_map(&p);
2104 for (j, q) in arm.pats.iter().enumerate() {
2109 let map_j = self.binding_mode_map(&q);
2110 for (&key, &binding_i) in &map_i {
2111 if map_j.len() == 0 { // Account for missing bindings when
2112 let binding_error = missing_vars // map_j has none.
2114 .or_insert(BindingError {
2116 origin: BTreeSet::new(),
2117 target: BTreeSet::new(),
2119 binding_error.origin.insert(binding_i.span);
2120 binding_error.target.insert(q.span);
2122 for (&key_j, &binding_j) in &map_j {
2123 match map_i.get(&key_j) {
2124 None => { // missing binding
2125 let binding_error = missing_vars
2127 .or_insert(BindingError {
2129 origin: BTreeSet::new(),
2130 target: BTreeSet::new(),
2132 binding_error.origin.insert(binding_j.span);
2133 binding_error.target.insert(p.span);
2135 Some(binding_i) => { // check consistent binding
2136 if binding_i.binding_mode != binding_j.binding_mode {
2139 .or_insert((binding_j.span, binding_i.span));
2147 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2148 missing_vars.sort();
2149 for (_, v) in missing_vars {
2151 *v.origin.iter().next().unwrap(),
2152 ResolutionError::VariableNotBoundInPattern(v));
2154 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2155 inconsistent_vars.sort();
2156 for (name, v) in inconsistent_vars {
2157 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2161 fn resolve_arm(&mut self, arm: &Arm) {
2162 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2164 let mut bindings_list = FxHashMap();
2165 for pattern in &arm.pats {
2166 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2169 // This has to happen *after* we determine which
2170 // pat_idents are variants
2171 self.check_consistent_bindings(arm);
2173 walk_list!(self, visit_expr, &arm.guard);
2174 self.visit_expr(&arm.body);
2176 self.ribs[ValueNS].pop();
2179 fn resolve_block(&mut self, block: &Block) {
2180 debug!("(resolving block) entering block");
2181 // Move down in the graph, if there's an anonymous module rooted here.
2182 let orig_module = self.current_module;
2183 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2185 let mut num_macro_definition_ribs = 0;
2186 if let Some(anonymous_module) = anonymous_module {
2187 debug!("(resolving block) found anonymous module, moving down");
2188 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2189 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2190 self.current_module = anonymous_module;
2191 self.finalize_current_module_macro_resolutions();
2193 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2196 // Descend into the block.
2197 for stmt in &block.stmts {
2198 if let ast::StmtKind::Item(ref item) = stmt.node {
2199 if let ast::ItemKind::MacroDef(..) = item.node {
2200 num_macro_definition_ribs += 1;
2201 let def = self.definitions.local_def_id(item.id);
2202 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2203 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2207 self.visit_stmt(stmt);
2211 self.current_module = orig_module;
2212 for _ in 0 .. num_macro_definition_ribs {
2213 self.ribs[ValueNS].pop();
2214 self.label_ribs.pop();
2216 self.ribs[ValueNS].pop();
2217 if let Some(_) = anonymous_module {
2218 self.ribs[TypeNS].pop();
2220 debug!("(resolving block) leaving block");
2223 fn fresh_binding(&mut self,
2224 ident: &SpannedIdent,
2226 outer_pat_id: NodeId,
2227 pat_src: PatternSource,
2228 bindings: &mut FxHashMap<Ident, NodeId>)
2230 // Add the binding to the local ribs, if it
2231 // doesn't already exist in the bindings map. (We
2232 // must not add it if it's in the bindings map
2233 // because that breaks the assumptions later
2234 // passes make about or-patterns.)
2235 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2236 match bindings.get(&ident.node).cloned() {
2237 Some(id) if id == outer_pat_id => {
2238 // `Variant(a, a)`, error
2242 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2243 &ident.node.name.as_str())
2246 Some(..) if pat_src == PatternSource::FnParam => {
2247 // `fn f(a: u8, a: u8)`, error
2251 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2252 &ident.node.name.as_str())
2255 Some(..) if pat_src == PatternSource::Match => {
2256 // `Variant1(a) | Variant2(a)`, ok
2257 // Reuse definition from the first `a`.
2258 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2261 span_bug!(ident.span, "two bindings with the same name from \
2262 unexpected pattern source {:?}", pat_src);
2265 // A completely fresh binding, add to the lists if it's valid.
2266 if ident.node.name != keywords::Invalid.name() {
2267 bindings.insert(ident.node, outer_pat_id);
2268 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2273 PathResolution::new(def)
2276 fn resolve_pattern(&mut self,
2278 pat_src: PatternSource,
2279 // Maps idents to the node ID for the
2280 // outermost pattern that binds them.
2281 bindings: &mut FxHashMap<Ident, NodeId>) {
2282 // Visit all direct subpatterns of this pattern.
2283 let outer_pat_id = pat.id;
2284 pat.walk(&mut |pat| {
2286 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2287 // First try to resolve the identifier as some existing
2288 // entity, then fall back to a fresh binding.
2289 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2291 .and_then(LexicalScopeBinding::item);
2292 let resolution = binding.map(NameBinding::def).and_then(|def| {
2293 let ivmode = BindingMode::ByValue(Mutability::Immutable);
2294 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2297 Def::StructCtor(_, CtorKind::Const) |
2298 Def::VariantCtor(_, CtorKind::Const) |
2299 Def::Const(..) if !always_binding => {
2300 // A unit struct/variant or constant pattern.
2301 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2302 Some(PathResolution::new(def))
2304 Def::StructCtor(..) | Def::VariantCtor(..) |
2305 Def::Const(..) | Def::Static(..) => {
2306 // A fresh binding that shadows something unacceptable.
2310 ResolutionError::BindingShadowsSomethingUnacceptable(
2311 pat_src.descr(), ident.node.name, binding.unwrap())
2315 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2316 // These entities are explicitly allowed
2317 // to be shadowed by fresh bindings.
2321 span_bug!(ident.span, "unexpected definition for an \
2322 identifier in pattern: {:?}", def);
2325 }).unwrap_or_else(|| {
2326 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2329 self.record_def(pat.id, resolution);
2332 PatKind::TupleStruct(ref path, ..) => {
2333 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2336 PatKind::Path(ref qself, ref path) => {
2337 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2340 PatKind::Struct(ref path, ..) => {
2341 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2349 visit::walk_pat(self, pat);
2352 // High-level and context dependent path resolution routine.
2353 // Resolves the path and records the resolution into definition map.
2354 // If resolution fails tries several techniques to find likely
2355 // resolution candidates, suggest imports or other help, and report
2356 // errors in user friendly way.
2357 fn smart_resolve_path(&mut self,
2359 qself: Option<&QSelf>,
2363 let segments = &path.segments.iter()
2364 .map(|seg| respan(seg.span, seg.identifier))
2365 .collect::<Vec<_>>();
2366 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2367 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2370 fn smart_resolve_path_fragment(&mut self,
2372 qself: Option<&QSelf>,
2373 path: &[SpannedIdent],
2378 let ns = source.namespace();
2379 let is_expected = &|def| source.is_expected(def);
2380 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2382 // Base error is amended with one short label and possibly some longer helps/notes.
2383 let report_errors = |this: &mut Self, def: Option<Def>| {
2384 // Make the base error.
2385 let expected = source.descr_expected();
2386 let path_str = names_to_string(path);
2387 let code = source.error_code(def.is_some());
2388 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2389 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2390 format!("not a {}", expected), span)
2392 let item_str = path[path.len() - 1].node;
2393 let item_span = path[path.len() - 1].span;
2394 let (mod_prefix, mod_str) = if path.len() == 1 {
2395 (format!(""), format!("this scope"))
2396 } else if path.len() == 2 && path[0].node.name == keywords::CrateRoot.name() {
2397 (format!(""), format!("the crate root"))
2399 let mod_path = &path[..path.len() - 1];
2400 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2401 PathResult::Module(module) => module.def(),
2403 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2404 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2406 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2407 format!("not found in {}", mod_str), item_span)
2409 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2411 // Emit special messages for unresolved `Self` and `self`.
2412 if is_self_type(path, ns) {
2413 __diagnostic_used!(E0411);
2414 err.code("E0411".into());
2415 err.span_label(span, "`Self` is only available in traits and impls");
2418 if is_self_value(path, ns) {
2419 __diagnostic_used!(E0424);
2420 err.code("E0424".into());
2421 err.span_label(span, format!("`self` value is only available in \
2422 methods with `self` parameter"));
2426 // Try to lookup the name in more relaxed fashion for better error reporting.
2427 let ident = *path.last().unwrap();
2428 let candidates = this.lookup_import_candidates(ident.node.name, ns, is_expected);
2429 if !candidates.is_empty() {
2430 let mut module_span = this.current_module.span;
2431 module_span.hi = module_span.lo;
2432 // Report import candidates as help and proceed searching for labels.
2433 show_candidates(&mut err, module_span, &candidates, def.is_some());
2434 } else if is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2435 let enum_candidates =
2436 this.lookup_import_candidates(ident.node.name, ns, is_enum_variant);
2437 let mut enum_candidates = enum_candidates.iter()
2438 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2439 enum_candidates.sort();
2440 for (sp, variant_path, enum_path) in enum_candidates {
2442 let msg = format!("there is an enum variant `{}`, \
2448 err.span_suggestion(span, "you can try using the variant's enum",
2453 if path.len() == 1 && this.self_type_is_available(span) {
2454 if let Some(candidate) = this.lookup_assoc_candidate(ident.node, ns, is_expected) {
2455 let self_is_available = this.self_value_is_available(path[0].node.ctxt, span);
2457 AssocSuggestion::Field => {
2458 err.span_suggestion(span, "try",
2459 format!("self.{}", path_str));
2460 if !self_is_available {
2461 err.span_label(span, format!("`self` value is only available in \
2462 methods with `self` parameter"));
2465 AssocSuggestion::MethodWithSelf if self_is_available => {
2466 err.span_suggestion(span, "try",
2467 format!("self.{}", path_str));
2469 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2470 err.span_suggestion(span, "try",
2471 format!("Self::{}", path_str));
2478 let mut levenshtein_worked = false;
2481 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2482 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2483 levenshtein_worked = true;
2486 // Try context dependent help if relaxed lookup didn't work.
2487 if let Some(def) = def {
2488 match (def, source) {
2489 (Def::Macro(..), _) => {
2490 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2493 (Def::TyAlias(..), PathSource::Trait) => {
2494 err.span_label(span, "type aliases cannot be used for traits");
2497 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2498 ExprKind::Field(_, ident) => {
2499 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2500 path_str, ident.node));
2503 ExprKind::MethodCall(ref segment, ..) => {
2504 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2505 path_str, segment.identifier));
2510 _ if ns == ValueNS && is_struct_like(def) => {
2511 if let Def::Struct(def_id) = def {
2512 if let Some((ctor_def, ctor_vis))
2513 = this.struct_constructors.get(&def_id).cloned() {
2514 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2515 err.span_label(span, format!("constructor is not visible \
2516 here due to private fields"));
2520 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2529 if !levenshtein_worked {
2530 err.span_label(base_span, fallback_label);
2531 this.type_ascription_suggestion(&mut err, base_span);
2535 let report_errors = |this: &mut Self, def: Option<Def>| {
2536 report_errors(this, def).emit();
2537 err_path_resolution()
2540 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2541 source.defer_to_typeck(),
2542 source.global_by_default()) {
2543 Some(resolution) if resolution.unresolved_segments() == 0 => {
2544 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2547 // Add a temporary hack to smooth the transition to new struct ctor
2548 // visibility rules. See #38932 for more details.
2550 if let Def::Struct(def_id) = resolution.base_def() {
2551 if let Some((ctor_def, ctor_vis))
2552 = self.struct_constructors.get(&def_id).cloned() {
2553 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2554 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2555 self.session.add_lint(lint, id, span,
2556 "private struct constructors are not usable through \
2557 reexports in outer modules".to_string());
2558 res = Some(PathResolution::new(ctor_def));
2563 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2566 Some(resolution) if source.defer_to_typeck() => {
2567 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2568 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2569 // it needs to be added to the trait map.
2571 let item_name = path.last().unwrap().node;
2572 let traits = self.get_traits_containing_item(item_name, ns);
2573 self.trait_map.insert(id, traits);
2577 _ => report_errors(self, None)
2580 if let PathSource::TraitItem(..) = source {} else {
2581 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2582 self.record_def(id, resolution);
2587 fn type_ascription_suggestion(&self,
2588 err: &mut DiagnosticBuilder,
2590 debug!("type_ascription_suggetion {:?}", base_span);
2591 let cm = self.session.codemap();
2592 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
2593 if let Some(sp) = self.current_type_ascription.last() {
2595 loop { // try to find the `:`, bail on first non-':'/non-whitespace
2596 sp = sp.next_point();
2597 if let Ok(snippet) = cm.span_to_snippet(sp.to(sp.next_point())) {
2598 debug!("snippet {:?}", snippet);
2599 let line_sp = cm.lookup_char_pos(sp.hi).line;
2600 let line_base_sp = cm.lookup_char_pos(base_span.lo).line;
2601 debug!("{:?} {:?}", line_sp, line_base_sp);
2603 err.span_label(base_span,
2604 "expecting a type here because of type ascription");
2605 if line_sp != line_base_sp {
2606 err.span_suggestion_short(sp,
2607 "did you mean to use `;` here instead?",
2611 } else if snippet.trim().len() != 0 {
2612 debug!("tried to find type ascription `:` token, couldn't find it");
2622 fn self_type_is_available(&mut self, span: Span) -> bool {
2623 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2624 TypeNS, false, span);
2625 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2628 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2629 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2630 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2631 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2634 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2635 fn resolve_qpath_anywhere(&mut self,
2637 qself: Option<&QSelf>,
2638 path: &[SpannedIdent],
2639 primary_ns: Namespace,
2641 defer_to_typeck: bool,
2642 global_by_default: bool)
2643 -> Option<PathResolution> {
2644 let mut fin_res = None;
2645 // FIXME: can't resolve paths in macro namespace yet, macros are
2646 // processed by the little special hack below.
2647 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2648 if i == 0 || ns != primary_ns {
2649 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2650 // If defer_to_typeck, then resolution > no resolution,
2651 // otherwise full resolution > partial resolution > no resolution.
2652 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2654 res => if fin_res.is_none() { fin_res = res },
2658 let is_global = self.global_macros.get(&path[0].node.name).cloned()
2659 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2660 if primary_ns != MacroNS && (is_global ||
2661 self.macro_names.contains(&path[0].node.modern())) {
2662 // Return some dummy definition, it's enough for error reporting.
2664 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2670 /// Handles paths that may refer to associated items.
2671 fn resolve_qpath(&mut self,
2673 qself: Option<&QSelf>,
2674 path: &[SpannedIdent],
2677 global_by_default: bool)
2678 -> Option<PathResolution> {
2679 if let Some(qself) = qself {
2680 if qself.position == 0 {
2681 // FIXME: Create some fake resolution that can't possibly be a type.
2682 return Some(PathResolution::with_unresolved_segments(
2683 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2686 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2687 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2688 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2689 span, span, PathSource::TraitItem(ns));
2690 return Some(PathResolution::with_unresolved_segments(
2691 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2695 let result = match self.resolve_path(&path, Some(ns), true, span) {
2696 PathResult::NonModule(path_res) => path_res,
2697 PathResult::Module(module) if !module.is_normal() => {
2698 PathResolution::new(module.def().unwrap())
2700 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2701 // don't report an error right away, but try to fallback to a primitive type.
2702 // So, we are still able to successfully resolve something like
2704 // use std::u8; // bring module u8 in scope
2705 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2706 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2707 // // not to non-existent std::u8::max_value
2710 // Such behavior is required for backward compatibility.
2711 // The same fallback is used when `a` resolves to nothing.
2712 PathResult::Module(..) | PathResult::Failed(..)
2713 if (ns == TypeNS || path.len() > 1) &&
2714 self.primitive_type_table.primitive_types
2715 .contains_key(&path[0].node.name) => {
2716 let prim = self.primitive_type_table.primitive_types[&path[0].node.name];
2718 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2719 if !self.session.features.borrow().i128_type {
2720 emit_feature_err(&self.session.parse_sess,
2721 "i128_type", span, GateIssue::Language,
2722 "128-bit type is unstable");
2728 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2730 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2731 PathResult::Failed(span, msg, false) => {
2732 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2733 err_path_resolution()
2735 PathResult::Failed(..) => return None,
2736 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2739 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2740 path[0].node.name != keywords::CrateRoot.name() &&
2741 path[0].node.name != keywords::DollarCrate.name() {
2742 let unqualified_result = {
2743 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2744 PathResult::NonModule(path_res) => path_res.base_def(),
2745 PathResult::Module(module) => module.def().unwrap(),
2746 _ => return Some(result),
2749 if result.base_def() == unqualified_result {
2750 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2751 self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
2758 fn resolve_path(&mut self,
2759 path: &[SpannedIdent],
2760 opt_ns: Option<Namespace>, // `None` indicates a module path
2764 let mut module = None;
2765 let mut allow_super = true;
2767 for (i, &ident) in path.iter().enumerate() {
2768 debug!("resolve_path ident {} {:?}", i, ident);
2769 let is_last = i == path.len() - 1;
2770 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2772 if i == 0 && ns == TypeNS && ident.node.name == keywords::SelfValue.name() {
2773 let mut ctxt = ident.node.ctxt.modern();
2774 module = Some(self.resolve_self(&mut ctxt, self.current_module));
2776 } else if allow_super && ns == TypeNS && ident.node.name == keywords::Super.name() {
2777 let mut ctxt = ident.node.ctxt.modern();
2778 let self_module = match i {
2779 0 => self.resolve_self(&mut ctxt, self.current_module),
2780 _ => module.unwrap(),
2782 if let Some(parent) = self_module.parent {
2783 module = Some(self.resolve_self(&mut ctxt, parent));
2786 let msg = "There are too many initial `super`s.".to_string();
2787 return PathResult::Failed(ident.span, msg, false);
2790 allow_super = false;
2792 if i == 0 && ns == TypeNS && ident.node.name == keywords::CrateRoot.name() {
2793 module = Some(self.resolve_crate_root(ident.node.ctxt.modern()));
2795 } else if i == 0 && ns == TypeNS && ident.node.name == keywords::DollarCrate.name() {
2796 module = Some(self.resolve_crate_root(ident.node.ctxt));
2800 let binding = if let Some(module) = module {
2801 self.resolve_ident_in_module(module, ident.node, ns, false, record_used, path_span)
2802 } else if opt_ns == Some(MacroNS) {
2803 self.resolve_lexical_macro_path_segment(ident.node, ns, record_used, path_span)
2804 .map(MacroBinding::binding)
2806 match self.resolve_ident_in_lexical_scope(ident.node, ns, record_used, path_span) {
2807 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2808 Some(LexicalScopeBinding::Def(def))
2809 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2810 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2814 _ => Err(if record_used { Determined } else { Undetermined }),
2820 let def = binding.def();
2821 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2822 if let Some(next_module) = binding.module() {
2823 module = Some(next_module);
2824 } else if def == Def::Err {
2825 return PathResult::NonModule(err_path_resolution());
2826 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2827 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2828 def, path.len() - i - 1
2831 return PathResult::Failed(ident.span,
2832 format!("Not a module `{}`", ident.node),
2836 Err(Undetermined) => return PathResult::Indeterminate,
2837 Err(Determined) => {
2838 if let Some(module) = module {
2839 if opt_ns.is_some() && !module.is_normal() {
2840 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2841 module.def().unwrap(), path.len() - i
2845 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2846 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2847 let mut candidates =
2848 self.lookup_import_candidates(ident.node.name, TypeNS, is_mod);
2849 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2850 if let Some(candidate) = candidates.get(0) {
2851 format!("Did you mean `{}`?", candidate.path)
2853 format!("Maybe a missing `extern crate {};`?", ident.node)
2856 format!("Use of undeclared type or module `{}`", ident.node)
2858 format!("Could not find `{}` in `{}`", ident.node, path[i - 1].node)
2860 return PathResult::Failed(ident.span, msg, is_last);
2865 PathResult::Module(module.unwrap_or(self.graph_root))
2868 // Resolve a local definition, potentially adjusting for closures.
2869 fn adjust_local_def(&mut self,
2874 span: Span) -> Def {
2875 let ribs = &self.ribs[ns][rib_index + 1..];
2877 // An invalid forward use of a type parameter from a previous default.
2878 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2880 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
2882 assert_eq!(def, Def::Err);
2888 span_bug!(span, "unexpected {:?} in bindings", def)
2890 Def::Local(def_id) => {
2893 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2894 ForwardTyParamBanRibKind => {
2895 // Nothing to do. Continue.
2897 ClosureRibKind(function_id) => {
2899 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2901 let seen = self.freevars_seen
2903 .or_insert_with(|| NodeMap());
2904 if let Some(&index) = seen.get(&node_id) {
2905 def = Def::Upvar(def_id, index, function_id);
2908 let vec = self.freevars
2910 .or_insert_with(|| vec![]);
2911 let depth = vec.len();
2912 def = Def::Upvar(def_id, depth, function_id);
2919 seen.insert(node_id, depth);
2922 ItemRibKind | MethodRibKind(_) => {
2923 // This was an attempt to access an upvar inside a
2924 // named function item. This is not allowed, so we
2927 resolve_error(self, span,
2928 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2932 ConstantItemRibKind => {
2933 // Still doesn't deal with upvars
2935 resolve_error(self, span,
2936 ResolutionError::AttemptToUseNonConstantValueInConstant);
2943 Def::TyParam(..) | Def::SelfTy(..) => {
2946 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2947 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
2948 ConstantItemRibKind => {
2949 // Nothing to do. Continue.
2952 // This was an attempt to use a type parameter outside
2955 resolve_error(self, span,
2956 ResolutionError::TypeParametersFromOuterFunction);
2968 // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
2969 // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
2970 // FIXME #34673: This needs testing.
2971 pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
2972 where F: FnOnce(&mut Resolver<'a>) -> T,
2974 self.with_empty_ribs(|this| {
2975 this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2976 this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2981 fn with_empty_ribs<T, F>(&mut self, f: F) -> T
2982 where F: FnOnce(&mut Resolver<'a>) -> T,
2984 let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
2985 let label_ribs = replace(&mut self.label_ribs, Vec::new());
2987 let result = f(self);
2989 self.label_ribs = label_ribs;
2993 fn lookup_assoc_candidate<FilterFn>(&mut self,
2996 filter_fn: FilterFn)
2997 -> Option<AssocSuggestion>
2998 where FilterFn: Fn(Def) -> bool
3000 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3002 TyKind::Path(None, _) => Some(t.id),
3003 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3004 // This doesn't handle the remaining `Ty` variants as they are not
3005 // that commonly the self_type, it might be interesting to provide
3006 // support for those in future.
3011 // Fields are generally expected in the same contexts as locals.
3012 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
3013 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3014 // Look for a field with the same name in the current self_type.
3015 if let Some(resolution) = self.def_map.get(&node_id) {
3016 match resolution.base_def() {
3017 Def::Struct(did) | Def::Union(did)
3018 if resolution.unresolved_segments() == 0 => {
3019 if let Some(field_names) = self.field_names.get(&did) {
3020 if field_names.iter().any(|&field_name| ident.name == field_name) {
3021 return Some(AssocSuggestion::Field);
3031 // Look for associated items in the current trait.
3032 if let Some((module, _)) = self.current_trait_ref {
3033 if let Ok(binding) =
3034 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3035 let def = binding.def();
3037 return Some(if self.has_self.contains(&def.def_id()) {
3038 AssocSuggestion::MethodWithSelf
3040 AssocSuggestion::AssocItem
3049 fn lookup_typo_candidate<FilterFn>(&mut self,
3050 path: &[SpannedIdent],
3052 filter_fn: FilterFn,
3055 where FilterFn: Fn(Def) -> bool
3057 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3058 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3059 if let Some(binding) = resolution.borrow().binding {
3060 if filter_fn(binding.def()) {
3061 names.push(ident.name);
3067 let mut names = Vec::new();
3068 if path.len() == 1 {
3069 // Search in lexical scope.
3070 // Walk backwards up the ribs in scope and collect candidates.
3071 for rib in self.ribs[ns].iter().rev() {
3072 // Locals and type parameters
3073 for (ident, def) in &rib.bindings {
3074 if filter_fn(*def) {
3075 names.push(ident.name);
3079 if let ModuleRibKind(module) = rib.kind {
3080 // Items from this module
3081 add_module_candidates(module, &mut names);
3083 if let ModuleKind::Block(..) = module.kind {
3084 // We can see through blocks
3086 // Items from the prelude
3087 if let Some(prelude) = self.prelude {
3088 if !module.no_implicit_prelude {
3089 add_module_candidates(prelude, &mut names);
3096 // Add primitive types to the mix
3097 if filter_fn(Def::PrimTy(TyBool)) {
3098 for (name, _) in &self.primitive_type_table.primitive_types {
3103 // Search in module.
3104 let mod_path = &path[..path.len() - 1];
3105 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3107 add_module_candidates(module, &mut names);
3111 let name = path[path.len() - 1].node.name;
3112 // Make sure error reporting is deterministic.
3113 names.sort_by_key(|name| name.as_str());
3114 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3115 Some(found) if found != name => Some(found),
3120 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
3121 where F: FnOnce(&mut Resolver)
3123 if let Some(label) = label {
3124 let def = Def::Label(id);
3125 self.with_label_rib(|this| {
3126 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
3134 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
3135 self.with_resolved_label(label, id, |this| this.visit_block(block));
3138 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3139 // First, record candidate traits for this expression if it could
3140 // result in the invocation of a method call.
3142 self.record_candidate_traits_for_expr_if_necessary(expr);
3144 // Next, resolve the node.
3146 ExprKind::Path(ref qself, ref path) => {
3147 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3148 visit::walk_expr(self, expr);
3151 ExprKind::Struct(ref path, ..) => {
3152 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3153 visit::walk_expr(self, expr);
3156 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3157 match self.search_label(label.node) {
3159 self.record_def(expr.id, err_path_resolution());
3162 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
3164 Some(def @ Def::Label(_)) => {
3165 // Since this def is a label, it is never read.
3166 self.record_def(expr.id, PathResolution::new(def));
3169 span_bug!(expr.span, "label wasn't mapped to a label def!");
3173 // visit `break` argument if any
3174 visit::walk_expr(self, expr);
3177 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
3178 self.visit_expr(subexpression);
3180 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3181 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
3182 self.visit_block(if_block);
3183 self.ribs[ValueNS].pop();
3185 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3188 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3190 ExprKind::While(ref subexpression, ref block, label) => {
3191 self.with_resolved_label(label, expr.id, |this| {
3192 this.visit_expr(subexpression);
3193 this.visit_block(block);
3197 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3198 self.with_resolved_label(label, expr.id, |this| {
3199 this.visit_expr(subexpression);
3200 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3201 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3202 this.visit_block(block);
3203 this.ribs[ValueNS].pop();
3207 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3208 self.visit_expr(subexpression);
3209 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3210 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3212 self.resolve_labeled_block(label, expr.id, block);
3214 self.ribs[ValueNS].pop();
3217 // Equivalent to `visit::walk_expr` + passing some context to children.
3218 ExprKind::Field(ref subexpression, _) => {
3219 self.resolve_expr(subexpression, Some(expr));
3221 ExprKind::MethodCall(ref segment, ref arguments) => {
3222 let mut arguments = arguments.iter();
3223 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3224 for argument in arguments {
3225 self.resolve_expr(argument, None);
3227 self.visit_path_segment(expr.span, segment);
3230 ExprKind::Repeat(ref element, ref count) => {
3231 self.visit_expr(element);
3232 self.with_constant_rib(|this| {
3233 this.visit_expr(count);
3236 ExprKind::Call(ref callee, ref arguments) => {
3237 self.resolve_expr(callee, Some(expr));
3238 for argument in arguments {
3239 self.resolve_expr(argument, None);
3242 ExprKind::Type(ref type_expr, _) => {
3243 self.current_type_ascription.push(type_expr.span);
3244 visit::walk_expr(self, expr);
3245 self.current_type_ascription.pop();
3248 visit::walk_expr(self, expr);
3253 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3255 ExprKind::Field(_, name) => {
3256 // FIXME(#6890): Even though you can't treat a method like a
3257 // field, we need to add any trait methods we find that match
3258 // the field name so that we can do some nice error reporting
3259 // later on in typeck.
3260 let traits = self.get_traits_containing_item(name.node, ValueNS);
3261 self.trait_map.insert(expr.id, traits);
3263 ExprKind::MethodCall(ref segment, ..) => {
3264 debug!("(recording candidate traits for expr) recording traits for {}",
3266 let traits = self.get_traits_containing_item(segment.identifier, ValueNS);
3267 self.trait_map.insert(expr.id, traits);
3275 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
3276 -> Vec<TraitCandidate> {
3277 debug!("(getting traits containing item) looking for '{}'", ident.name);
3279 let mut found_traits = Vec::new();
3280 // Look for the current trait.
3281 if let Some((module, _)) = self.current_trait_ref {
3282 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3283 let def_id = module.def_id().unwrap();
3284 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3288 ident.ctxt = ident.ctxt.modern();
3289 let mut search_module = self.current_module;
3291 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3293 unwrap_or!(self.hygienic_lexical_parent(search_module, &mut ident.ctxt), break);
3296 if let Some(prelude) = self.prelude {
3297 if !search_module.no_implicit_prelude {
3298 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3305 fn get_traits_in_module_containing_item(&mut self,
3309 found_traits: &mut Vec<TraitCandidate>) {
3310 let mut traits = module.traits.borrow_mut();
3311 if traits.is_none() {
3312 let mut collected_traits = Vec::new();
3313 module.for_each_child(|name, ns, binding| {
3314 if ns != TypeNS { return }
3315 if let Def::Trait(_) = binding.def() {
3316 collected_traits.push((name, binding));
3319 *traits = Some(collected_traits.into_boxed_slice());
3322 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3323 let module = binding.module().unwrap();
3324 let mut ident = ident;
3325 if ident.ctxt.glob_adjust(module.expansion, binding.span.ctxt.modern()).is_none() {
3328 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
3330 let import_id = match binding.kind {
3331 NameBindingKind::Import { directive, .. } => {
3332 self.maybe_unused_trait_imports.insert(directive.id);
3333 self.add_to_glob_map(directive.id, trait_name);
3338 let trait_def_id = module.def_id().unwrap();
3339 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3344 /// When name resolution fails, this method can be used to look up candidate
3345 /// entities with the expected name. It allows filtering them using the
3346 /// supplied predicate (which should be used to only accept the types of
3347 /// definitions expected e.g. traits). The lookup spans across all crates.
3349 /// NOTE: The method does not look into imports, but this is not a problem,
3350 /// since we report the definitions (thus, the de-aliased imports).
3351 fn lookup_import_candidates<FilterFn>(&mut self,
3353 namespace: Namespace,
3354 filter_fn: FilterFn)
3355 -> Vec<ImportSuggestion>
3356 where FilterFn: Fn(Def) -> bool
3358 let mut candidates = Vec::new();
3359 let mut worklist = Vec::new();
3360 let mut seen_modules = FxHashSet();
3361 worklist.push((self.graph_root, Vec::new(), false));
3363 while let Some((in_module,
3365 in_module_is_extern)) = worklist.pop() {
3366 self.populate_module_if_necessary(in_module);
3368 // We have to visit module children in deterministic order to avoid
3369 // instabilities in reported imports (#43552).
3370 in_module.for_each_child_stable(|ident, ns, name_binding| {
3371 // avoid imports entirely
3372 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3373 // avoid non-importable candidates as well
3374 if !name_binding.is_importable() { return; }
3376 // collect results based on the filter function
3377 if ident.name == lookup_name && ns == namespace {
3378 if filter_fn(name_binding.def()) {
3380 let mut segms = path_segments.clone();
3381 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3383 span: name_binding.span,
3386 // the entity is accessible in the following cases:
3387 // 1. if it's defined in the same crate, it's always
3388 // accessible (since private entities can be made public)
3389 // 2. if it's defined in another crate, it's accessible
3390 // only if both the module is public and the entity is
3391 // declared as public (due to pruning, we don't explore
3392 // outside crate private modules => no need to check this)
3393 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3394 candidates.push(ImportSuggestion { path: path });
3399 // collect submodules to explore
3400 if let Some(module) = name_binding.module() {
3402 let mut path_segments = path_segments.clone();
3403 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3405 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3406 // add the module to the lookup
3407 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3408 if seen_modules.insert(module.def_id().unwrap()) {
3409 worklist.push((module, path_segments, is_extern));
3419 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3420 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3421 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3422 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3426 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3428 ast::Visibility::Public => ty::Visibility::Public,
3429 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3430 ast::Visibility::Inherited => {
3431 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3433 ast::Visibility::Restricted { ref path, id } => {
3434 let def = self.smart_resolve_path(id, None, path,
3435 PathSource::Visibility).base_def();
3436 if def == Def::Err {
3437 ty::Visibility::Public
3439 let vis = ty::Visibility::Restricted(def.def_id());
3440 if self.is_accessible(vis) {
3443 self.session.span_err(path.span, "visibilities can only be restricted \
3444 to ancestor modules");
3445 ty::Visibility::Public
3452 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3453 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3456 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3457 vis.is_accessible_from(module.normal_ancestor_id, self)
3460 fn report_errors(&mut self) {
3461 self.report_shadowing_errors();
3462 let mut reported_spans = FxHashSet();
3464 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3465 if !reported_spans.insert(span) { continue }
3466 let participle = |binding: &NameBinding| {
3467 if binding.is_import() { "imported" } else { "defined" }
3469 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3470 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3471 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3472 format!("consider adding an explicit import of `{}` to disambiguate", name)
3473 } else if let Def::Macro(..) = b1.def() {
3474 format!("macro-expanded {} do not shadow",
3475 if b1.is_import() { "macro imports" } else { "macros" })
3477 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3478 if b1.is_import() { "imports" } else { "items" })
3481 let id = match b2.kind {
3482 NameBindingKind::Import { directive, .. } => directive.id,
3483 _ => unreachable!(),
3485 let mut span = MultiSpan::from_span(span);
3486 span.push_span_label(b1.span, msg1);
3487 span.push_span_label(b2.span, msg2);
3488 let msg = format!("`{}` is ambiguous", name);
3489 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3492 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3493 err.span_note(b1.span, &msg1);
3495 Def::Macro(..) if b2.span == DUMMY_SP =>
3496 err.note(&format!("`{}` is also a builtin macro", name)),
3497 _ => err.span_note(b2.span, &msg2),
3499 err.note(¬e).emit();
3503 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3504 if !reported_spans.insert(span) { continue }
3505 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
3509 fn report_shadowing_errors(&mut self) {
3510 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3511 self.resolve_legacy_scope(scope, ident, true);
3514 let mut reported_errors = FxHashSet();
3515 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3516 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
3517 reported_errors.insert((binding.ident, binding.span)) {
3518 let msg = format!("`{}` is already in scope", binding.ident);
3519 self.session.struct_span_err(binding.span, &msg)
3520 .note("macro-expanded `macro_rules!`s may not shadow \
3521 existing macros (see RFC 1560)")
3527 fn report_conflict(&mut self,
3531 new_binding: &NameBinding,
3532 old_binding: &NameBinding) {
3533 // Error on the second of two conflicting names
3534 if old_binding.span.lo > new_binding.span.lo {
3535 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3538 let container = match parent.kind {
3539 ModuleKind::Def(Def::Mod(_), _) => "module",
3540 ModuleKind::Def(Def::Trait(_), _) => "trait",
3541 ModuleKind::Block(..) => "block",
3545 let old_noun = match old_binding.is_import() {
3547 false => "definition",
3550 let new_participle = match new_binding.is_import() {
3555 let (name, span) = (ident.name, new_binding.span);
3557 if let Some(s) = self.name_already_seen.get(&name) {
3563 let old_kind = match (ns, old_binding.module()) {
3564 (ValueNS, _) => "value",
3565 (MacroNS, _) => "macro",
3566 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3567 (TypeNS, Some(module)) if module.is_normal() => "module",
3568 (TypeNS, Some(module)) if module.is_trait() => "trait",
3569 (TypeNS, _) => "type",
3572 let namespace = match ns {
3578 let msg = format!("the name `{}` is defined multiple times", name);
3580 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3581 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3582 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3583 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3584 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3586 _ => match (old_binding.is_import(), new_binding.is_import()) {
3587 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3588 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3589 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3593 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
3598 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3599 if old_binding.span != syntax_pos::DUMMY_SP {
3600 err.span_label(old_binding.span, format!("previous {} of the {} `{}` here",
3601 old_noun, old_kind, name));
3605 self.name_already_seen.insert(name, span);
3608 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3609 let (id, span) = (directive.id, directive.span);
3610 let msg = "`self` no longer imports values".to_string();
3611 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3614 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3615 if self.proc_macro_enabled { return; }
3618 if attr.path.segments.len() > 1 {
3621 let ident = attr.path.segments[0].identifier;
3622 let result = self.resolve_lexical_macro_path_segment(ident,
3626 if let Ok(binding) = result {
3627 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3628 attr::mark_known(attr);
3630 let msg = "attribute procedural macros are experimental";
3631 let feature = "proc_macro";
3633 feature_err(&self.session.parse_sess, feature,
3634 attr.span, GateIssue::Language, msg)
3635 .span_note(binding.span(), "procedural macro imported here")
3643 fn is_struct_like(def: Def) -> bool {
3645 Def::VariantCtor(_, CtorKind::Fictive) => true,
3646 _ => PathSource::Struct.is_expected(def),
3650 fn is_self_type(path: &[SpannedIdent], namespace: Namespace) -> bool {
3651 namespace == TypeNS && path.len() == 1 && path[0].node.name == keywords::SelfType.name()
3654 fn is_self_value(path: &[SpannedIdent], namespace: Namespace) -> bool {
3655 namespace == ValueNS && path.len() == 1 && path[0].node.name == keywords::SelfValue.name()
3658 fn names_to_string(idents: &[SpannedIdent]) -> String {
3659 let mut result = String::new();
3660 for (i, ident) in idents.iter()
3661 .filter(|i| i.node.name != keywords::CrateRoot.name())
3664 result.push_str("::");
3666 result.push_str(&ident.node.name.as_str());
3671 fn path_names_to_string(path: &Path) -> String {
3672 names_to_string(&path.segments.iter()
3673 .map(|seg| respan(seg.span, seg.identifier))
3674 .collect::<Vec<_>>())
3677 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3678 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3679 let variant_path = &suggestion.path;
3680 let variant_path_string = path_names_to_string(variant_path);
3682 let path_len = suggestion.path.segments.len();
3683 let enum_path = ast::Path {
3684 span: suggestion.path.span,
3685 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3687 let enum_path_string = path_names_to_string(&enum_path);
3689 (suggestion.path.span, variant_path_string, enum_path_string)
3693 /// When an entity with a given name is not available in scope, we search for
3694 /// entities with that name in all crates. This method allows outputting the
3695 /// results of this search in a programmer-friendly way
3696 fn show_candidates(err: &mut DiagnosticBuilder,
3698 candidates: &[ImportSuggestion],
3701 // we want consistent results across executions, but candidates are produced
3702 // by iterating through a hash map, so make sure they are ordered:
3703 let mut path_strings: Vec<_> =
3704 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3705 path_strings.sort();
3707 let better = if better { "better " } else { "" };
3708 let msg_diff = match path_strings.len() {
3709 1 => " is found in another module, you can import it",
3710 _ => "s are found in other modules, you can import them",
3712 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3714 for candidate in &mut path_strings {
3715 *candidate = format!("use {};\n", candidate);
3718 err.span_suggestions(span, &msg, path_strings);
3721 /// A somewhat inefficient routine to obtain the name of a module.
3722 fn module_to_string(module: Module) -> String {
3723 let mut names = Vec::new();
3725 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3726 if let ModuleKind::Def(_, name) = module.kind {
3727 if let Some(parent) = module.parent {
3728 names.push(Ident::with_empty_ctxt(name));
3729 collect_mod(names, parent);
3732 // danger, shouldn't be ident?
3733 names.push(Ident::from_str("<opaque>"));
3734 collect_mod(names, module.parent.unwrap());
3737 collect_mod(&mut names, module);
3739 if names.is_empty() {
3740 return "???".to_string();
3742 names_to_string(&names.into_iter()
3744 .map(|n| dummy_spanned(n))
3745 .collect::<Vec<_>>())
3748 fn err_path_resolution() -> PathResolution {
3749 PathResolution::new(Def::Err)
3752 #[derive(PartialEq,Copy, Clone)]
3753 pub enum MakeGlobMap {
3758 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }