1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
16 #![feature(rustc_diagnostic_macros)]
22 extern crate syntax_pos;
23 extern crate rustc_errors as errors;
28 use self::Namespace::*;
29 use self::TypeParameters::*;
32 use rustc::hir::map::{Definitions, DefCollector};
33 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
34 use rustc::middle::cstore::CrateLoader;
35 use rustc::session::Session;
37 use rustc::hir::def::*;
38 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
40 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
41 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
43 use syntax::codemap::{dummy_spanned, respan};
44 use syntax::ext::hygiene::{Mark, SyntaxContext};
45 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
46 use syntax::ext::base::SyntaxExtension;
47 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
48 use syntax::ext::base::MacroKind;
49 use syntax::symbol::{Symbol, keywords};
50 use syntax::util::lev_distance::find_best_match_for_name;
52 use syntax::visit::{self, FnKind, Visitor};
54 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
55 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
56 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
57 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
58 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
59 use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
61 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
62 use errors::DiagnosticBuilder;
64 use std::cell::{Cell, RefCell};
66 use std::collections::BTreeSet;
68 use std::mem::replace;
71 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
72 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
74 // NB: This module needs to be declared first so diagnostics are
75 // registered before they are used.
80 mod build_reduced_graph;
83 /// A free importable items suggested in case of resolution failure.
84 struct ImportSuggestion {
88 /// A field or associated item from self type suggested in case of resolution failure.
89 enum AssocSuggestion {
98 origin: BTreeSet<Span>,
99 target: BTreeSet<Span>,
102 impl PartialOrd for BindingError {
103 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
104 Some(self.cmp(other))
108 impl PartialEq for BindingError {
109 fn eq(&self, other: &BindingError) -> bool {
110 self.name == other.name
114 impl Ord for BindingError {
115 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
116 self.name.cmp(&other.name)
120 enum ResolutionError<'a> {
121 /// error E0401: can't use type parameters from outer function
122 TypeParametersFromOuterFunction,
123 /// error E0403: the name is already used for a type parameter in this type parameter list
124 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
125 /// error E0407: method is not a member of trait
126 MethodNotMemberOfTrait(Name, &'a str),
127 /// error E0437: type is not a member of trait
128 TypeNotMemberOfTrait(Name, &'a str),
129 /// error E0438: const is not a member of trait
130 ConstNotMemberOfTrait(Name, &'a str),
131 /// error E0408: variable `{}` is not bound in all patterns
132 VariableNotBoundInPattern(&'a BindingError),
133 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
134 VariableBoundWithDifferentMode(Name, Span),
135 /// error E0415: identifier is bound more than once in this parameter list
136 IdentifierBoundMoreThanOnceInParameterList(&'a str),
137 /// error E0416: identifier is bound more than once in the same pattern
138 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
139 /// error E0426: use of undeclared label
140 UndeclaredLabel(&'a str),
141 /// error E0429: `self` imports are only allowed within a { } list
142 SelfImportsOnlyAllowedWithin,
143 /// error E0430: `self` import can only appear once in the list
144 SelfImportCanOnlyAppearOnceInTheList,
145 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
146 SelfImportOnlyInImportListWithNonEmptyPrefix,
147 /// error E0432: unresolved import
148 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
149 /// error E0433: failed to resolve
150 FailedToResolve(&'a str),
151 /// error E0434: can't capture dynamic environment in a fn item
152 CannotCaptureDynamicEnvironmentInFnItem,
153 /// error E0435: attempt to use a non-constant value in a constant
154 AttemptToUseNonConstantValueInConstant,
155 /// error E0530: X bindings cannot shadow Ys
156 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
157 /// error E0128: type parameters with a default cannot use forward declared identifiers
158 ForwardDeclaredTyParam,
161 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
163 resolution_error: ResolutionError<'a>) {
164 resolve_struct_error(resolver, span, resolution_error).emit();
167 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
169 resolution_error: ResolutionError<'a>)
170 -> DiagnosticBuilder<'sess> {
171 match resolution_error {
172 ResolutionError::TypeParametersFromOuterFunction => {
173 let mut err = struct_span_err!(resolver.session,
176 "can't use type parameters from outer function; \
177 try using a local type parameter instead");
178 err.span_label(span, "use of type variable from outer function");
181 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
182 let mut err = struct_span_err!(resolver.session,
185 "the name `{}` is already used for a type parameter \
186 in this type parameter list",
188 err.span_label(span, "already used");
189 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
192 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
193 let mut err = struct_span_err!(resolver.session,
196 "method `{}` is not a member of trait `{}`",
199 err.span_label(span, format!("not a member of trait `{}`", trait_));
202 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
203 let mut err = struct_span_err!(resolver.session,
206 "type `{}` is not a member of trait `{}`",
209 err.span_label(span, format!("not a member of trait `{}`", trait_));
212 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
213 let mut err = struct_span_err!(resolver.session,
216 "const `{}` is not a member of trait `{}`",
219 err.span_label(span, format!("not a member of trait `{}`", trait_));
222 ResolutionError::VariableNotBoundInPattern(binding_error) => {
223 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
224 let msp = MultiSpan::from_spans(target_sp.clone());
225 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
226 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
227 for sp in target_sp {
228 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
230 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
231 for sp in origin_sp {
232 err.span_label(sp, "variable not in all patterns");
236 ResolutionError::VariableBoundWithDifferentMode(variable_name,
237 first_binding_span) => {
238 let mut err = struct_span_err!(resolver.session,
241 "variable `{}` is bound in inconsistent \
242 ways within the same match arm",
244 err.span_label(span, "bound in different ways");
245 err.span_label(first_binding_span, "first binding");
248 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
249 let mut err = struct_span_err!(resolver.session,
252 "identifier `{}` is bound more than once in this parameter list",
254 err.span_label(span, "used as parameter more than once");
257 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
258 let mut err = struct_span_err!(resolver.session,
261 "identifier `{}` is bound more than once in the same pattern",
263 err.span_label(span, "used in a pattern more than once");
266 ResolutionError::UndeclaredLabel(name) => {
267 let mut err = struct_span_err!(resolver.session,
270 "use of undeclared label `{}`",
272 err.span_label(span, format!("undeclared label `{}`", name));
275 ResolutionError::SelfImportsOnlyAllowedWithin => {
276 struct_span_err!(resolver.session,
280 "`self` imports are only allowed within a { } list")
282 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
283 struct_span_err!(resolver.session,
286 "`self` import can only appear once in the list")
288 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
289 struct_span_err!(resolver.session,
292 "`self` import can only appear in an import list with a \
295 ResolutionError::UnresolvedImport(name) => {
296 let (span, msg) = match name {
297 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
298 None => (span, "unresolved import".to_owned()),
300 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
301 if let Some((_, _, p)) = name {
302 err.span_label(span, p);
306 ResolutionError::FailedToResolve(msg) => {
307 let mut err = struct_span_err!(resolver.session, span, E0433,
308 "failed to resolve. {}", msg);
309 err.span_label(span, msg);
312 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
313 struct_span_err!(resolver.session,
317 "can't capture dynamic environment in a fn item; use the || { ... } \
318 closure form instead")
320 ResolutionError::AttemptToUseNonConstantValueInConstant => {
321 let mut err = struct_span_err!(resolver.session,
324 "attempt to use a non-constant value in a constant");
325 err.span_label(span, "non-constant value");
328 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
329 let shadows_what = PathResolution::new(binding.def()).kind_name();
330 let mut err = struct_span_err!(resolver.session,
333 "{}s cannot shadow {}s", what_binding, shadows_what);
334 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
335 let participle = if binding.is_import() { "imported" } else { "defined" };
336 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
337 err.span_label(binding.span, msg);
340 ResolutionError::ForwardDeclaredTyParam => {
341 let mut err = struct_span_err!(resolver.session, span, E0128,
342 "type parameters with a default cannot use \
343 forward declared identifiers");
344 err.span_label(span, format!("defaulted type parameters \
345 cannot be forward declared"));
351 #[derive(Copy, Clone, Debug)]
354 binding_mode: BindingMode,
357 // Map from the name in a pattern to its binding mode.
358 type BindingMap = FxHashMap<Ident, BindingInfo>;
360 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
371 fn is_refutable(self) -> bool {
373 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
374 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
377 fn descr(self) -> &'static str {
379 PatternSource::Match => "match binding",
380 PatternSource::IfLet => "if let binding",
381 PatternSource::WhileLet => "while let binding",
382 PatternSource::Let => "let binding",
383 PatternSource::For => "for binding",
384 PatternSource::FnParam => "function parameter",
389 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
390 enum PathSource<'a> {
391 // Type paths `Path`.
393 // Trait paths in bounds or impls.
395 // Expression paths `path`, with optional parent context.
396 Expr(Option<&'a Expr>),
397 // Paths in path patterns `Path`.
399 // Paths in struct expressions and patterns `Path { .. }`.
401 // Paths in tuple struct patterns `Path(..)`.
403 // `m::A::B` in `<T as m::A>::B::C`.
404 TraitItem(Namespace),
405 // Path in `pub(path)`
407 // Path in `use a::b::{...};`
411 impl<'a> PathSource<'a> {
412 fn namespace(self) -> Namespace {
414 PathSource::Type | PathSource::Trait | PathSource::Struct |
415 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
416 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
417 PathSource::TraitItem(ns) => ns,
421 fn global_by_default(self) -> bool {
423 PathSource::Visibility | PathSource::ImportPrefix => true,
424 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
425 PathSource::Struct | PathSource::TupleStruct |
426 PathSource::Trait | PathSource::TraitItem(..) => false,
430 fn defer_to_typeck(self) -> bool {
432 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
433 PathSource::Struct | PathSource::TupleStruct => true,
434 PathSource::Trait | PathSource::TraitItem(..) |
435 PathSource::Visibility | PathSource::ImportPrefix => false,
439 fn descr_expected(self) -> &'static str {
441 PathSource::Type => "type",
442 PathSource::Trait => "trait",
443 PathSource::Pat => "unit struct/variant or constant",
444 PathSource::Struct => "struct, variant or union type",
445 PathSource::TupleStruct => "tuple struct/variant",
446 PathSource::Visibility => "module",
447 PathSource::ImportPrefix => "module or enum",
448 PathSource::TraitItem(ns) => match ns {
449 TypeNS => "associated type",
450 ValueNS => "method or associated constant",
451 MacroNS => bug!("associated macro"),
453 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
454 // "function" here means "anything callable" rather than `Def::Fn`,
455 // this is not precise but usually more helpful than just "value".
456 Some(&ExprKind::Call(..)) => "function",
462 fn is_expected(self, def: Def) -> bool {
464 PathSource::Type => match def {
465 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
466 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
467 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
470 PathSource::Trait => match def {
471 Def::Trait(..) => true,
474 PathSource::Expr(..) => match def {
475 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
476 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
477 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
478 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
481 PathSource::Pat => match def {
482 Def::StructCtor(_, CtorKind::Const) |
483 Def::VariantCtor(_, CtorKind::Const) |
484 Def::Const(..) | Def::AssociatedConst(..) => true,
487 PathSource::TupleStruct => match def {
488 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
491 PathSource::Struct => match def {
492 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
493 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
496 PathSource::TraitItem(ns) => match def {
497 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
498 Def::AssociatedTy(..) if ns == TypeNS => true,
501 PathSource::ImportPrefix => match def {
502 Def::Mod(..) | Def::Enum(..) => true,
505 PathSource::Visibility => match def {
506 Def::Mod(..) => true,
512 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
513 __diagnostic_used!(E0404);
514 __diagnostic_used!(E0405);
515 __diagnostic_used!(E0412);
516 __diagnostic_used!(E0422);
517 __diagnostic_used!(E0423);
518 __diagnostic_used!(E0425);
519 __diagnostic_used!(E0531);
520 __diagnostic_used!(E0532);
521 __diagnostic_used!(E0573);
522 __diagnostic_used!(E0574);
523 __diagnostic_used!(E0575);
524 __diagnostic_used!(E0576);
525 __diagnostic_used!(E0577);
526 __diagnostic_used!(E0578);
527 match (self, has_unexpected_resolution) {
528 (PathSource::Trait, true) => "E0404",
529 (PathSource::Trait, false) => "E0405",
530 (PathSource::Type, true) => "E0573",
531 (PathSource::Type, false) => "E0412",
532 (PathSource::Struct, true) => "E0574",
533 (PathSource::Struct, false) => "E0422",
534 (PathSource::Expr(..), true) => "E0423",
535 (PathSource::Expr(..), false) => "E0425",
536 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
537 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
538 (PathSource::TraitItem(..), true) => "E0575",
539 (PathSource::TraitItem(..), false) => "E0576",
540 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
541 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
546 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
553 #[derive(Clone, Default, Debug)]
554 pub struct PerNS<T> {
560 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
562 fn index(&self, ns: Namespace) -> &T {
564 ValueNS => &self.value_ns,
565 TypeNS => &self.type_ns,
566 MacroNS => self.macro_ns.as_ref().unwrap(),
571 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
572 fn index_mut(&mut self, ns: Namespace) -> &mut T {
574 ValueNS => &mut self.value_ns,
575 TypeNS => &mut self.type_ns,
576 MacroNS => self.macro_ns.as_mut().unwrap(),
581 struct UsePlacementFinder {
582 target_module: NodeId,
587 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
590 module: &'tcx ast::Mod,
592 _: &[ast::Attribute],
595 if self.span.is_some() {
598 if node_id != self.target_module {
599 visit::walk_mod(self, module);
602 // find a use statement
603 for item in &module.items {
605 ItemKind::Use(..) => {
606 // don't suggest placing a use before the prelude
607 // import or other generated ones
608 if item.span == DUMMY_SP {
609 self.span = Some(item.span.with_hi(item.span.lo()));
610 self.found_use = true;
614 // don't place use before extern crate
615 ItemKind::ExternCrate(_) => {}
616 // but place them before the first other item
617 _ => if self.span.map_or(true, |span| item.span < span ) {
618 self.span = Some(item.span.with_hi(item.span.lo()));
622 assert!(self.span.is_some(), "a file can't have no items and emit suggestions");
626 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
627 fn visit_item(&mut self, item: &'tcx Item) {
628 self.resolve_item(item);
630 fn visit_arm(&mut self, arm: &'tcx Arm) {
631 self.resolve_arm(arm);
633 fn visit_block(&mut self, block: &'tcx Block) {
634 self.resolve_block(block);
636 fn visit_expr(&mut self, expr: &'tcx Expr) {
637 self.resolve_expr(expr, None);
639 fn visit_local(&mut self, local: &'tcx Local) {
640 self.resolve_local(local);
642 fn visit_ty(&mut self, ty: &'tcx Ty) {
644 TyKind::Path(ref qself, ref path) => {
645 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
647 TyKind::ImplicitSelf => {
648 let self_ty = keywords::SelfType.ident();
649 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
650 .map_or(Def::Err, |d| d.def());
651 self.record_def(ty.id, PathResolution::new(def));
653 TyKind::Array(ref element, ref length) => {
654 self.visit_ty(element);
655 self.with_constant_rib(|this| {
656 this.visit_expr(length);
662 visit::walk_ty(self, ty);
664 fn visit_poly_trait_ref(&mut self,
665 tref: &'tcx ast::PolyTraitRef,
666 m: &'tcx ast::TraitBoundModifier) {
667 self.smart_resolve_path(tref.trait_ref.ref_id, None,
668 &tref.trait_ref.path, PathSource::Trait);
669 visit::walk_poly_trait_ref(self, tref, m);
671 fn visit_variant(&mut self,
672 variant: &'tcx ast::Variant,
673 generics: &'tcx Generics,
674 item_id: ast::NodeId) {
675 if let Some(ref dis_expr) = variant.node.disr_expr {
676 // resolve the discriminator expr as a constant
677 self.with_constant_rib(|this| {
678 this.visit_expr(dis_expr);
682 // `visit::walk_variant` without the discriminant expression.
683 self.visit_variant_data(&variant.node.data,
689 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
690 let type_parameters = match foreign_item.node {
691 ForeignItemKind::Fn(_, ref generics) => {
692 HasTypeParameters(generics, ItemRibKind)
694 ForeignItemKind::Static(..) => NoTypeParameters,
696 self.with_type_parameter_rib(type_parameters, |this| {
697 visit::walk_foreign_item(this, foreign_item);
700 fn visit_fn(&mut self,
701 function_kind: FnKind<'tcx>,
702 declaration: &'tcx FnDecl,
705 let rib_kind = match function_kind {
706 FnKind::ItemFn(_, generics, ..) => {
707 self.visit_generics(generics);
710 FnKind::Method(_, sig, _, _) => {
711 self.visit_generics(&sig.generics);
712 MethodRibKind(!sig.decl.has_self())
714 FnKind::Closure(_) => ClosureRibKind(node_id),
717 // Create a value rib for the function.
718 self.ribs[ValueNS].push(Rib::new(rib_kind));
720 // Create a label rib for the function.
721 self.label_ribs.push(Rib::new(rib_kind));
723 // Add each argument to the rib.
724 let mut bindings_list = FxHashMap();
725 for argument in &declaration.inputs {
726 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
728 self.visit_ty(&argument.ty);
730 debug!("(resolving function) recorded argument");
732 visit::walk_fn_ret_ty(self, &declaration.output);
734 // Resolve the function body.
735 match function_kind {
736 FnKind::ItemFn(.., body) |
737 FnKind::Method(.., body) => {
738 self.visit_block(body);
740 FnKind::Closure(body) => {
741 self.visit_expr(body);
745 debug!("(resolving function) leaving function");
747 self.label_ribs.pop();
748 self.ribs[ValueNS].pop();
750 fn visit_generics(&mut self, generics: &'tcx Generics) {
751 // For type parameter defaults, we have to ban access
752 // to following type parameters, as the Substs can only
753 // provide previous type parameters as they're built.
754 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
755 default_ban_rib.bindings.extend(generics.ty_params.iter()
756 .skip_while(|p| p.default.is_none())
757 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
759 for param in &generics.ty_params {
760 for bound in ¶m.bounds {
761 self.visit_ty_param_bound(bound);
764 if let Some(ref ty) = param.default {
765 self.ribs[TypeNS].push(default_ban_rib);
767 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
770 // Allow all following defaults to refer to this type parameter.
771 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
773 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
774 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
778 #[derive(Copy, Clone)]
779 enum TypeParameters<'a, 'b> {
781 HasTypeParameters(// Type parameters.
784 // The kind of the rib used for type parameters.
788 // The rib kind controls the translation of local
789 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
790 #[derive(Copy, Clone, Debug)]
792 // No translation needs to be applied.
795 // We passed through a closure scope at the given node ID.
796 // Translate upvars as appropriate.
797 ClosureRibKind(NodeId /* func id */),
799 // We passed through an impl or trait and are now in one of its
800 // methods. Allow references to ty params that impl or trait
801 // binds. Disallow any other upvars (including other ty params that are
804 // The boolean value represents the fact that this method is static or not.
807 // We passed through an item scope. Disallow upvars.
810 // We're in a constant item. Can't refer to dynamic stuff.
813 // We passed through a module.
814 ModuleRibKind(Module<'a>),
816 // We passed through a `macro_rules!` statement
817 MacroDefinition(DefId),
819 // All bindings in this rib are type parameters that can't be used
820 // from the default of a type parameter because they're not declared
821 // before said type parameter. Also see the `visit_generics` override.
822 ForwardTyParamBanRibKind,
828 bindings: FxHashMap<Ident, Def>,
833 fn new(kind: RibKind<'a>) -> Rib<'a> {
835 bindings: FxHashMap(),
841 enum LexicalScopeBinding<'a> {
842 Item(&'a NameBinding<'a>),
846 impl<'a> LexicalScopeBinding<'a> {
847 fn item(self) -> Option<&'a NameBinding<'a>> {
849 LexicalScopeBinding::Item(binding) => Some(binding),
854 fn def(self) -> Def {
856 LexicalScopeBinding::Item(binding) => binding.def(),
857 LexicalScopeBinding::Def(def) => def,
863 enum PathResult<'a> {
865 NonModule(PathResolution),
867 Failed(Span, String, bool /* is the error from the last segment? */),
875 /// One node in the tree of modules.
876 pub struct ModuleData<'a> {
877 parent: Option<Module<'a>>,
880 // The def id of the closest normal module (`mod`) ancestor (including this module).
881 normal_ancestor_id: DefId,
883 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
884 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
885 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
887 // Macro invocations that can expand into items in this module.
888 unresolved_invocations: RefCell<FxHashSet<Mark>>,
890 no_implicit_prelude: bool,
892 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
893 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
895 // Used to memoize the traits in this module for faster searches through all traits in scope.
896 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
898 // Whether this module is populated. If not populated, any attempt to
899 // access the children must be preceded with a
900 // `populate_module_if_necessary` call.
901 populated: Cell<bool>,
903 /// Span of the module itself. Used for error reporting.
909 type Module<'a> = &'a ModuleData<'a>;
911 impl<'a> ModuleData<'a> {
912 fn new(parent: Option<Module<'a>>,
914 normal_ancestor_id: DefId,
916 span: Span) -> Self {
921 resolutions: RefCell::new(FxHashMap()),
922 legacy_macro_resolutions: RefCell::new(Vec::new()),
923 macro_resolutions: RefCell::new(Vec::new()),
924 unresolved_invocations: RefCell::new(FxHashSet()),
925 no_implicit_prelude: false,
926 glob_importers: RefCell::new(Vec::new()),
927 globs: RefCell::new((Vec::new())),
928 traits: RefCell::new(None),
929 populated: Cell::new(normal_ancestor_id.is_local()),
935 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
936 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
937 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
941 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
942 let resolutions = self.resolutions.borrow();
943 let mut resolutions = resolutions.iter().map(|(&(ident, ns), &resolution)| {
944 // Pre-compute keys for sorting
945 (ident.name.as_str(), ns, ident, resolution)
947 .collect::<Vec<_>>();
948 resolutions.sort_unstable_by_key(|&(str, ns, ..)| (str, ns));
949 for &(_, ns, ident, resolution) in resolutions.iter() {
950 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
954 fn def(&self) -> Option<Def> {
956 ModuleKind::Def(def, _) => Some(def),
961 fn def_id(&self) -> Option<DefId> {
962 self.def().as_ref().map(Def::def_id)
965 // `self` resolves to the first module ancestor that `is_normal`.
966 fn is_normal(&self) -> bool {
968 ModuleKind::Def(Def::Mod(_), _) => true,
973 fn is_trait(&self) -> bool {
975 ModuleKind::Def(Def::Trait(_), _) => true,
980 fn is_local(&self) -> bool {
981 self.normal_ancestor_id.is_local()
984 fn nearest_item_scope(&'a self) -> Module<'a> {
985 if self.is_trait() { self.parent.unwrap() } else { self }
989 impl<'a> fmt::Debug for ModuleData<'a> {
990 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
991 write!(f, "{:?}", self.def())
995 // Records a possibly-private value, type, or module definition.
996 #[derive(Clone, Debug)]
997 pub struct NameBinding<'a> {
998 kind: NameBindingKind<'a>,
1001 vis: ty::Visibility,
1004 pub trait ToNameBinding<'a> {
1005 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1008 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1009 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1014 #[derive(Clone, Debug)]
1015 enum NameBindingKind<'a> {
1019 binding: &'a NameBinding<'a>,
1020 directive: &'a ImportDirective<'a>,
1022 legacy_self_import: bool,
1025 b1: &'a NameBinding<'a>,
1026 b2: &'a NameBinding<'a>,
1031 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1033 struct UseError<'a> {
1034 err: DiagnosticBuilder<'a>,
1035 /// Attach `use` statements for these candidates
1036 candidates: Vec<ImportSuggestion>,
1037 /// The node id of the module to place the use statements in
1039 /// Whether the diagnostic should state that it's "better"
1043 struct AmbiguityError<'a> {
1047 b1: &'a NameBinding<'a>,
1048 b2: &'a NameBinding<'a>,
1052 impl<'a> NameBinding<'a> {
1053 fn module(&self) -> Option<Module<'a>> {
1055 NameBindingKind::Module(module) => Some(module),
1056 NameBindingKind::Import { binding, .. } => binding.module(),
1057 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1062 fn def(&self) -> Def {
1064 NameBindingKind::Def(def) => def,
1065 NameBindingKind::Module(module) => module.def().unwrap(),
1066 NameBindingKind::Import { binding, .. } => binding.def(),
1067 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1068 NameBindingKind::Ambiguity { .. } => Def::Err,
1072 fn def_ignoring_ambiguity(&self) -> Def {
1074 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1075 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1080 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
1081 resolver.get_macro(self.def_ignoring_ambiguity())
1084 // We sometimes need to treat variants as `pub` for backwards compatibility
1085 fn pseudo_vis(&self) -> ty::Visibility {
1086 if self.is_variant() { ty::Visibility::Public } else { self.vis }
1089 fn is_variant(&self) -> bool {
1091 NameBindingKind::Def(Def::Variant(..)) |
1092 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1097 fn is_extern_crate(&self) -> bool {
1099 NameBindingKind::Import {
1100 directive: &ImportDirective {
1101 subclass: ImportDirectiveSubclass::ExternCrate, ..
1108 fn is_import(&self) -> bool {
1110 NameBindingKind::Import { .. } => true,
1115 fn is_glob_import(&self) -> bool {
1117 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1118 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1123 fn is_importable(&self) -> bool {
1125 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1130 fn is_macro_def(&self) -> bool {
1132 NameBindingKind::Def(Def::Macro(..)) => true,
1137 fn descr(&self) -> &'static str {
1138 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1142 /// Interns the names of the primitive types.
1143 struct PrimitiveTypeTable {
1144 primitive_types: FxHashMap<Name, PrimTy>,
1147 impl PrimitiveTypeTable {
1148 fn new() -> PrimitiveTypeTable {
1149 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1151 table.intern("bool", TyBool);
1152 table.intern("char", TyChar);
1153 table.intern("f32", TyFloat(FloatTy::F32));
1154 table.intern("f64", TyFloat(FloatTy::F64));
1155 table.intern("isize", TyInt(IntTy::Is));
1156 table.intern("i8", TyInt(IntTy::I8));
1157 table.intern("i16", TyInt(IntTy::I16));
1158 table.intern("i32", TyInt(IntTy::I32));
1159 table.intern("i64", TyInt(IntTy::I64));
1160 table.intern("i128", TyInt(IntTy::I128));
1161 table.intern("str", TyStr);
1162 table.intern("usize", TyUint(UintTy::Us));
1163 table.intern("u8", TyUint(UintTy::U8));
1164 table.intern("u16", TyUint(UintTy::U16));
1165 table.intern("u32", TyUint(UintTy::U32));
1166 table.intern("u64", TyUint(UintTy::U64));
1167 table.intern("u128", TyUint(UintTy::U128));
1171 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1172 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1176 /// The main resolver class.
1177 pub struct Resolver<'a> {
1178 session: &'a Session,
1180 pub definitions: Definitions,
1182 graph_root: Module<'a>,
1184 prelude: Option<Module<'a>>,
1186 // n.b. This is used only for better diagnostics, not name resolution itself.
1187 has_self: FxHashSet<DefId>,
1189 // Names of fields of an item `DefId` accessible with dot syntax.
1190 // Used for hints during error reporting.
1191 field_names: FxHashMap<DefId, Vec<Name>>,
1193 // All imports known to succeed or fail.
1194 determined_imports: Vec<&'a ImportDirective<'a>>,
1196 // All non-determined imports.
1197 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1199 // The module that represents the current item scope.
1200 current_module: Module<'a>,
1202 // The current set of local scopes for types and values.
1203 // FIXME #4948: Reuse ribs to avoid allocation.
1204 ribs: PerNS<Vec<Rib<'a>>>,
1206 // The current set of local scopes, for labels.
1207 label_ribs: Vec<Rib<'a>>,
1209 // The trait that the current context can refer to.
1210 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1212 // The current self type if inside an impl (used for better errors).
1213 current_self_type: Option<Ty>,
1215 // The idents for the primitive types.
1216 primitive_type_table: PrimitiveTypeTable,
1219 pub freevars: FreevarMap,
1220 freevars_seen: NodeMap<NodeMap<usize>>,
1221 pub export_map: ExportMap,
1222 pub trait_map: TraitMap,
1224 // A map from nodes to anonymous modules.
1225 // Anonymous modules are pseudo-modules that are implicitly created around items
1226 // contained within blocks.
1228 // For example, if we have this:
1236 // There will be an anonymous module created around `g` with the ID of the
1237 // entry block for `f`.
1238 block_map: NodeMap<Module<'a>>,
1239 module_map: FxHashMap<DefId, Module<'a>>,
1240 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1242 pub make_glob_map: bool,
1243 /// Maps imports to the names of items actually imported (this actually maps
1244 /// all imports, but only glob imports are actually interesting).
1245 pub glob_map: GlobMap,
1247 used_imports: FxHashSet<(NodeId, Namespace)>,
1248 pub maybe_unused_trait_imports: NodeSet,
1249 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1251 /// privacy errors are delayed until the end in order to deduplicate them
1252 privacy_errors: Vec<PrivacyError<'a>>,
1253 /// ambiguity errors are delayed for deduplication
1254 ambiguity_errors: Vec<AmbiguityError<'a>>,
1255 /// `use` injections are delayed for better placement and deduplication
1256 use_injections: Vec<UseError<'a>>,
1258 gated_errors: FxHashSet<Span>,
1259 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1261 arenas: &'a ResolverArenas<'a>,
1262 dummy_binding: &'a NameBinding<'a>,
1263 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1265 crate_loader: &'a mut CrateLoader,
1266 macro_names: FxHashSet<Ident>,
1267 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1268 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1269 macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
1270 macro_defs: FxHashMap<Mark, DefId>,
1271 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1272 macro_exports: Vec<Export>,
1273 pub whitelisted_legacy_custom_derives: Vec<Name>,
1274 pub found_unresolved_macro: bool,
1276 // List of crate local macros that we need to warn about as being unused.
1277 // Right now this only includes macro_rules! macros, and macros 2.0.
1278 unused_macros: FxHashSet<DefId>,
1280 // Maps the `Mark` of an expansion to its containing module or block.
1281 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1283 // Avoid duplicated errors for "name already defined".
1284 name_already_seen: FxHashMap<Name, Span>,
1286 // If `#![feature(proc_macro)]` is set
1287 proc_macro_enabled: bool,
1289 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1290 warned_proc_macros: FxHashSet<Name>,
1292 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1294 // This table maps struct IDs into struct constructor IDs,
1295 // it's not used during normal resolution, only for better error reporting.
1296 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1298 // Only used for better errors on `fn(): fn()`
1299 current_type_ascription: Vec<Span>,
1302 pub struct ResolverArenas<'a> {
1303 modules: arena::TypedArena<ModuleData<'a>>,
1304 local_modules: RefCell<Vec<Module<'a>>>,
1305 name_bindings: arena::TypedArena<NameBinding<'a>>,
1306 import_directives: arena::TypedArena<ImportDirective<'a>>,
1307 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1308 invocation_data: arena::TypedArena<InvocationData<'a>>,
1309 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1312 impl<'a> ResolverArenas<'a> {
1313 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1314 let module = self.modules.alloc(module);
1315 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1316 self.local_modules.borrow_mut().push(module);
1320 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1321 self.local_modules.borrow()
1323 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1324 self.name_bindings.alloc(name_binding)
1326 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1327 -> &'a ImportDirective {
1328 self.import_directives.alloc(import_directive)
1330 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1331 self.name_resolutions.alloc(Default::default())
1333 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1334 -> &'a InvocationData<'a> {
1335 self.invocation_data.alloc(expansion_data)
1337 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1338 self.legacy_bindings.alloc(binding)
1342 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1343 fn parent(self, id: DefId) -> Option<DefId> {
1345 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1346 _ => self.session.cstore.def_key(id).parent,
1347 }.map(|index| DefId { index: index, ..id })
1351 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1352 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1353 let namespace = if is_value { ValueNS } else { TypeNS };
1354 let hir::Path { ref segments, span, ref mut def } = *path;
1355 let path: Vec<SpannedIdent> = segments.iter()
1356 .map(|seg| respan(span, Ident::with_empty_ctxt(seg.name)))
1358 match self.resolve_path(&path, Some(namespace), true, span) {
1359 PathResult::Module(module) => *def = module.def().unwrap(),
1360 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1361 *def = path_res.base_def(),
1362 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1363 PathResult::Failed(span, msg, _) => {
1364 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1368 PathResult::Indeterminate => unreachable!(),
1369 PathResult::Failed(span, msg, _) => {
1370 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1375 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1376 self.def_map.get(&id).cloned()
1379 fn definitions(&mut self) -> &mut Definitions {
1380 &mut self.definitions
1384 impl<'a> Resolver<'a> {
1385 pub fn new(session: &'a Session,
1388 make_glob_map: MakeGlobMap,
1389 crate_loader: &'a mut CrateLoader,
1390 arenas: &'a ResolverArenas<'a>)
1392 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1393 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1394 let graph_root = arenas.alloc_module(ModuleData {
1395 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1396 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1398 let mut module_map = FxHashMap();
1399 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1401 let mut definitions = Definitions::new();
1402 DefCollector::new(&mut definitions, Mark::root())
1403 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1405 let mut invocations = FxHashMap();
1406 invocations.insert(Mark::root(),
1407 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1409 let features = session.features.borrow();
1411 let mut macro_defs = FxHashMap();
1412 macro_defs.insert(Mark::root(), root_def_id);
1419 // The outermost module has def ID 0; this is not reflected in the
1424 has_self: FxHashSet(),
1425 field_names: FxHashMap(),
1427 determined_imports: Vec::new(),
1428 indeterminate_imports: Vec::new(),
1430 current_module: graph_root,
1432 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1433 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1434 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1436 label_ribs: Vec::new(),
1438 current_trait_ref: None,
1439 current_self_type: None,
1441 primitive_type_table: PrimitiveTypeTable::new(),
1444 freevars: NodeMap(),
1445 freevars_seen: NodeMap(),
1446 export_map: NodeMap(),
1447 trait_map: NodeMap(),
1449 block_map: NodeMap(),
1450 extern_module_map: FxHashMap(),
1452 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1453 glob_map: NodeMap(),
1455 used_imports: FxHashSet(),
1456 maybe_unused_trait_imports: NodeSet(),
1457 maybe_unused_extern_crates: Vec::new(),
1459 privacy_errors: Vec::new(),
1460 ambiguity_errors: Vec::new(),
1461 use_injections: Vec::new(),
1462 gated_errors: FxHashSet(),
1463 disallowed_shadowing: Vec::new(),
1466 dummy_binding: arenas.alloc_name_binding(NameBinding {
1467 kind: NameBindingKind::Def(Def::Err),
1468 expansion: Mark::root(),
1470 vis: ty::Visibility::Public,
1473 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1475 features.use_extern_macros || features.proc_macro || features.decl_macro,
1478 macro_names: FxHashSet(),
1479 global_macros: FxHashMap(),
1480 lexical_macro_resolutions: Vec::new(),
1481 macro_map: FxHashMap(),
1482 macro_exports: Vec::new(),
1485 local_macro_def_scopes: FxHashMap(),
1486 name_already_seen: FxHashMap(),
1487 whitelisted_legacy_custom_derives: Vec::new(),
1488 proc_macro_enabled: features.proc_macro,
1489 warned_proc_macros: FxHashSet(),
1490 potentially_unused_imports: Vec::new(),
1491 struct_constructors: DefIdMap(),
1492 found_unresolved_macro: false,
1493 unused_macros: FxHashSet(),
1494 current_type_ascription: Vec::new(),
1498 pub fn arenas() -> ResolverArenas<'a> {
1500 modules: arena::TypedArena::new(),
1501 local_modules: RefCell::new(Vec::new()),
1502 name_bindings: arena::TypedArena::new(),
1503 import_directives: arena::TypedArena::new(),
1504 name_resolutions: arena::TypedArena::new(),
1505 invocation_data: arena::TypedArena::new(),
1506 legacy_bindings: arena::TypedArena::new(),
1510 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1512 type_ns: f(self, TypeNS),
1513 value_ns: f(self, ValueNS),
1514 macro_ns: match self.use_extern_macros {
1515 true => Some(f(self, MacroNS)),
1521 /// Entry point to crate resolution.
1522 pub fn resolve_crate(&mut self, krate: &Crate) {
1523 ImportResolver { resolver: self }.finalize_imports();
1524 self.current_module = self.graph_root;
1525 self.finalize_current_module_macro_resolutions();
1527 visit::walk_crate(self, krate);
1529 check_unused::check_crate(self, krate);
1530 self.report_errors(krate);
1531 self.crate_loader.postprocess(krate);
1538 normal_ancestor_id: DefId,
1542 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1543 self.arenas.alloc_module(module)
1546 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1547 -> bool /* true if an error was reported */ {
1548 match binding.kind {
1549 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1552 directive.used.set(true);
1553 if legacy_self_import {
1554 self.warn_legacy_self_import(directive);
1557 self.used_imports.insert((directive.id, ns));
1558 self.add_to_glob_map(directive.id, ident);
1559 self.record_use(ident, ns, binding, span)
1561 NameBindingKind::Import { .. } => false,
1562 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1563 self.ambiguity_errors.push(AmbiguityError {
1564 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy,
1567 self.record_use(ident, ns, b1, span);
1575 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1576 if self.make_glob_map {
1577 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1581 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1582 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1583 /// `ident` in the first scope that defines it (or None if no scopes define it).
1585 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1586 /// the items are defined in the block. For example,
1589 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1592 /// g(); // This resolves to the local variable `g` since it shadows the item.
1596 /// Invariant: This must only be called during main resolution, not during
1597 /// import resolution.
1598 fn resolve_ident_in_lexical_scope(&mut self,
1603 -> Option<LexicalScopeBinding<'a>> {
1605 ident.ctxt = if ident.name == keywords::SelfType.name() {
1606 SyntaxContext::empty() // FIXME(jseyfried) improve `Self` hygiene
1612 // Walk backwards up the ribs in scope.
1613 let mut module = self.graph_root;
1614 for i in (0 .. self.ribs[ns].len()).rev() {
1615 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1616 // The ident resolves to a type parameter or local variable.
1617 return Some(LexicalScopeBinding::Def(
1618 self.adjust_local_def(ns, i, def, record_used, path_span)
1622 module = match self.ribs[ns][i].kind {
1623 ModuleRibKind(module) => module,
1624 MacroDefinition(def) if def == self.macro_defs[&ident.ctxt.outer()] => {
1625 // If an invocation of this macro created `ident`, give up on `ident`
1626 // and switch to `ident`'s source from the macro definition.
1627 ident.ctxt.remove_mark();
1633 let item = self.resolve_ident_in_module_unadjusted(
1634 module, ident, ns, false, record_used, path_span,
1636 if let Ok(binding) = item {
1637 // The ident resolves to an item.
1638 return Some(LexicalScopeBinding::Item(binding));
1642 ModuleKind::Block(..) => {}, // We can see through blocks
1647 ident.ctxt = ident.ctxt.modern();
1649 module = unwrap_or!(self.hygienic_lexical_parent(module, &mut ident.ctxt), break);
1650 let orig_current_module = self.current_module;
1651 self.current_module = module; // Lexical resolutions can never be a privacy error.
1652 let result = self.resolve_ident_in_module_unadjusted(
1653 module, ident, ns, false, record_used, path_span,
1655 self.current_module = orig_current_module;
1658 Ok(binding) => return Some(LexicalScopeBinding::Item(binding)),
1659 Err(Undetermined) => return None,
1660 Err(Determined) => {}
1664 match self.prelude {
1665 Some(prelude) if !module.no_implicit_prelude => {
1666 self.resolve_ident_in_module_unadjusted(prelude, ident, ns, false, false, path_span)
1667 .ok().map(LexicalScopeBinding::Item)
1673 fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, ctxt: &mut SyntaxContext)
1674 -> Option<Module<'a>> {
1675 if !module.expansion.is_descendant_of(ctxt.outer()) {
1676 return Some(self.macro_def_scope(ctxt.remove_mark()));
1679 if let ModuleKind::Block(..) = module.kind {
1680 return Some(module.parent.unwrap());
1683 let mut module_expansion = module.expansion.modern(); // for backward compatibility
1684 while let Some(parent) = module.parent {
1685 let parent_expansion = parent.expansion.modern();
1686 if module_expansion.is_descendant_of(parent_expansion) &&
1687 parent_expansion != module_expansion {
1688 return if parent_expansion.is_descendant_of(ctxt.outer()) {
1695 module_expansion = parent_expansion;
1701 fn resolve_ident_in_module(&mut self,
1705 ignore_unresolved_invocations: bool,
1708 -> Result<&'a NameBinding<'a>, Determinacy> {
1709 ident.ctxt = ident.ctxt.modern();
1710 let orig_current_module = self.current_module;
1711 if let Some(def) = ident.ctxt.adjust(module.expansion) {
1712 self.current_module = self.macro_def_scope(def);
1714 let result = self.resolve_ident_in_module_unadjusted(
1715 module, ident, ns, ignore_unresolved_invocations, record_used, span,
1717 self.current_module = orig_current_module;
1721 fn resolve_crate_root(&mut self, mut ctxt: SyntaxContext) -> Module<'a> {
1722 let module = match ctxt.adjust(Mark::root()) {
1723 Some(def) => self.macro_def_scope(def),
1724 None => return self.graph_root,
1726 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1729 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1730 let mut module = self.get_module(module.normal_ancestor_id);
1731 while module.span.ctxt().modern() != *ctxt {
1732 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1733 module = self.get_module(parent.normal_ancestor_id);
1740 // We maintain a list of value ribs and type ribs.
1742 // Simultaneously, we keep track of the current position in the module
1743 // graph in the `current_module` pointer. When we go to resolve a name in
1744 // the value or type namespaces, we first look through all the ribs and
1745 // then query the module graph. When we resolve a name in the module
1746 // namespace, we can skip all the ribs (since nested modules are not
1747 // allowed within blocks in Rust) and jump straight to the current module
1750 // Named implementations are handled separately. When we find a method
1751 // call, we consult the module node to find all of the implementations in
1752 // scope. This information is lazily cached in the module node. We then
1753 // generate a fake "implementation scope" containing all the
1754 // implementations thus found, for compatibility with old resolve pass.
1756 fn with_scope<F>(&mut self, id: NodeId, f: F)
1757 where F: FnOnce(&mut Resolver)
1759 let id = self.definitions.local_def_id(id);
1760 let module = self.module_map.get(&id).cloned(); // clones a reference
1761 if let Some(module) = module {
1762 // Move down in the graph.
1763 let orig_module = replace(&mut self.current_module, module);
1764 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1765 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1767 self.finalize_current_module_macro_resolutions();
1770 self.current_module = orig_module;
1771 self.ribs[ValueNS].pop();
1772 self.ribs[TypeNS].pop();
1778 /// Searches the current set of local scopes for labels.
1779 /// Stops after meeting a closure.
1780 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1781 for rib in self.label_ribs.iter().rev() {
1784 // If an invocation of this macro created `ident`, give up on `ident`
1785 // and switch to `ident`'s source from the macro definition.
1786 MacroDefinition(def) => {
1787 if def == self.macro_defs[&ident.ctxt.outer()] {
1788 ident.ctxt.remove_mark();
1792 // Do not resolve labels across function boundary
1796 let result = rib.bindings.get(&ident).cloned();
1797 if result.is_some() {
1804 fn resolve_item(&mut self, item: &Item) {
1805 let name = item.ident.name;
1807 debug!("(resolving item) resolving {}", name);
1809 self.check_proc_macro_attrs(&item.attrs);
1812 ItemKind::Enum(_, ref generics) |
1813 ItemKind::Ty(_, ref generics) |
1814 ItemKind::Struct(_, ref generics) |
1815 ItemKind::Union(_, ref generics) |
1816 ItemKind::Fn(.., ref generics, _) => {
1817 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1818 |this| visit::walk_item(this, item));
1821 ItemKind::DefaultImpl(_, ref trait_ref) => {
1822 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1823 // Resolve type arguments in trait path
1824 visit::walk_trait_ref(this, trait_ref);
1827 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1828 self.resolve_implementation(generics,
1834 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1835 // Create a new rib for the trait-wide type parameters.
1836 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1837 let local_def_id = this.definitions.local_def_id(item.id);
1838 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1839 this.visit_generics(generics);
1840 walk_list!(this, visit_ty_param_bound, bounds);
1842 for trait_item in trait_items {
1843 this.check_proc_macro_attrs(&trait_item.attrs);
1845 match trait_item.node {
1846 TraitItemKind::Const(ref ty, ref default) => {
1849 // Only impose the restrictions of
1850 // ConstRibKind for an actual constant
1851 // expression in a provided default.
1852 if let Some(ref expr) = *default{
1853 this.with_constant_rib(|this| {
1854 this.visit_expr(expr);
1858 TraitItemKind::Method(ref sig, _) => {
1859 let type_parameters =
1860 HasTypeParameters(&sig.generics,
1861 MethodRibKind(!sig.decl.has_self()));
1862 this.with_type_parameter_rib(type_parameters, |this| {
1863 visit::walk_trait_item(this, trait_item)
1866 TraitItemKind::Type(..) => {
1867 this.with_type_parameter_rib(NoTypeParameters, |this| {
1868 visit::walk_trait_item(this, trait_item)
1871 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1878 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1879 self.with_scope(item.id, |this| {
1880 visit::walk_item(this, item);
1884 ItemKind::Static(ref ty, _, ref expr) |
1885 ItemKind::Const(ref ty, ref expr) => {
1886 self.with_item_rib(|this| {
1888 this.with_constant_rib(|this| {
1889 this.visit_expr(expr);
1894 ItemKind::Use(ref view_path) => {
1895 match view_path.node {
1896 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1897 // Resolve prefix of an import with empty braces (issue #28388).
1898 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1904 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1905 // do nothing, these are just around to be encoded
1908 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1912 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1913 where F: FnOnce(&mut Resolver)
1915 match type_parameters {
1916 HasTypeParameters(generics, rib_kind) => {
1917 let mut function_type_rib = Rib::new(rib_kind);
1918 let mut seen_bindings = FxHashMap();
1919 for type_parameter in &generics.ty_params {
1920 let ident = type_parameter.ident.modern();
1921 debug!("with_type_parameter_rib: {}", type_parameter.id);
1923 if seen_bindings.contains_key(&ident) {
1924 let span = seen_bindings.get(&ident).unwrap();
1926 ResolutionError::NameAlreadyUsedInTypeParameterList(ident.name, span);
1927 resolve_error(self, type_parameter.span, err);
1929 seen_bindings.entry(ident).or_insert(type_parameter.span);
1931 // plain insert (no renaming)
1932 let def_id = self.definitions.local_def_id(type_parameter.id);
1933 let def = Def::TyParam(def_id);
1934 function_type_rib.bindings.insert(ident, def);
1935 self.record_def(type_parameter.id, PathResolution::new(def));
1937 self.ribs[TypeNS].push(function_type_rib);
1940 NoTypeParameters => {
1947 if let HasTypeParameters(..) = type_parameters {
1948 self.ribs[TypeNS].pop();
1952 fn with_label_rib<F>(&mut self, f: F)
1953 where F: FnOnce(&mut Resolver)
1955 self.label_ribs.push(Rib::new(NormalRibKind));
1957 self.label_ribs.pop();
1960 fn with_item_rib<F>(&mut self, f: F)
1961 where F: FnOnce(&mut Resolver)
1963 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
1964 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
1966 self.ribs[TypeNS].pop();
1967 self.ribs[ValueNS].pop();
1970 fn with_constant_rib<F>(&mut self, f: F)
1971 where F: FnOnce(&mut Resolver)
1973 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1975 self.ribs[ValueNS].pop();
1978 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1979 where F: FnOnce(&mut Resolver) -> T
1981 // Handle nested impls (inside fn bodies)
1982 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1983 let result = f(self);
1984 self.current_self_type = previous_value;
1988 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1989 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1991 let mut new_val = None;
1992 let mut new_id = None;
1993 if let Some(trait_ref) = opt_trait_ref {
1994 let path: Vec<_> = trait_ref.path.segments.iter()
1995 .map(|seg| respan(seg.span, seg.identifier))
1997 let def = self.smart_resolve_path_fragment(trait_ref.ref_id,
2000 trait_ref.path.span,
2001 trait_ref.path.segments.last().unwrap().span,
2004 if def != Def::Err {
2005 new_id = Some(def.def_id());
2006 let span = trait_ref.path.span;
2007 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span) {
2008 new_val = Some((module, trait_ref.clone()));
2012 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2013 let result = f(self, new_id);
2014 self.current_trait_ref = original_trait_ref;
2018 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2019 where F: FnOnce(&mut Resolver)
2021 let mut self_type_rib = Rib::new(NormalRibKind);
2023 // plain insert (no renaming, types are not currently hygienic....)
2024 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2025 self.ribs[TypeNS].push(self_type_rib);
2027 self.ribs[TypeNS].pop();
2030 fn resolve_implementation(&mut self,
2031 generics: &Generics,
2032 opt_trait_reference: &Option<TraitRef>,
2035 impl_items: &[ImplItem]) {
2036 // If applicable, create a rib for the type parameters.
2037 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2038 // Dummy self type for better errors if `Self` is used in the trait path.
2039 this.with_self_rib(Def::SelfTy(None, None), |this| {
2040 // Resolve the trait reference, if necessary.
2041 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2042 let item_def_id = this.definitions.local_def_id(item_id);
2043 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2044 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2045 // Resolve type arguments in trait path
2046 visit::walk_trait_ref(this, trait_ref);
2048 // Resolve the self type.
2049 this.visit_ty(self_type);
2050 // Resolve the type parameters.
2051 this.visit_generics(generics);
2052 this.with_current_self_type(self_type, |this| {
2053 for impl_item in impl_items {
2054 this.check_proc_macro_attrs(&impl_item.attrs);
2055 this.resolve_visibility(&impl_item.vis);
2056 match impl_item.node {
2057 ImplItemKind::Const(..) => {
2058 // If this is a trait impl, ensure the const
2060 this.check_trait_item(impl_item.ident,
2063 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
2064 visit::walk_impl_item(this, impl_item);
2066 ImplItemKind::Method(ref sig, _) => {
2067 // If this is a trait impl, ensure the method
2069 this.check_trait_item(impl_item.ident,
2072 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
2074 // We also need a new scope for the method-
2075 // specific type parameters.
2076 let type_parameters =
2077 HasTypeParameters(&sig.generics,
2078 MethodRibKind(!sig.decl.has_self()));
2079 this.with_type_parameter_rib(type_parameters, |this| {
2080 visit::walk_impl_item(this, impl_item);
2083 ImplItemKind::Type(ref ty) => {
2084 // If this is a trait impl, ensure the type
2086 this.check_trait_item(impl_item.ident,
2089 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
2093 ImplItemKind::Macro(_) =>
2094 panic!("unexpanded macro in resolve!"),
2104 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2105 where F: FnOnce(Name, &str) -> ResolutionError
2107 // If there is a TraitRef in scope for an impl, then the method must be in the
2109 if let Some((module, _)) = self.current_trait_ref {
2110 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2111 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2112 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2117 fn resolve_local(&mut self, local: &Local) {
2118 // Resolve the type.
2119 walk_list!(self, visit_ty, &local.ty);
2121 // Resolve the initializer.
2122 walk_list!(self, visit_expr, &local.init);
2124 // Resolve the pattern.
2125 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2128 // build a map from pattern identifiers to binding-info's.
2129 // this is done hygienically. This could arise for a macro
2130 // that expands into an or-pattern where one 'x' was from the
2131 // user and one 'x' came from the macro.
2132 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2133 let mut binding_map = FxHashMap();
2135 pat.walk(&mut |pat| {
2136 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2137 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2138 Some(Def::Local(..)) => true,
2141 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2142 binding_map.insert(ident.node, binding_info);
2151 // check that all of the arms in an or-pattern have exactly the
2152 // same set of bindings, with the same binding modes for each.
2153 fn check_consistent_bindings(&mut self, arm: &Arm) {
2154 if arm.pats.is_empty() {
2158 let mut missing_vars = FxHashMap();
2159 let mut inconsistent_vars = FxHashMap();
2160 for (i, p) in arm.pats.iter().enumerate() {
2161 let map_i = self.binding_mode_map(&p);
2163 for (j, q) in arm.pats.iter().enumerate() {
2168 let map_j = self.binding_mode_map(&q);
2169 for (&key, &binding_i) in &map_i {
2170 if map_j.len() == 0 { // Account for missing bindings when
2171 let binding_error = missing_vars // map_j has none.
2173 .or_insert(BindingError {
2175 origin: BTreeSet::new(),
2176 target: BTreeSet::new(),
2178 binding_error.origin.insert(binding_i.span);
2179 binding_error.target.insert(q.span);
2181 for (&key_j, &binding_j) in &map_j {
2182 match map_i.get(&key_j) {
2183 None => { // missing binding
2184 let binding_error = missing_vars
2186 .or_insert(BindingError {
2188 origin: BTreeSet::new(),
2189 target: BTreeSet::new(),
2191 binding_error.origin.insert(binding_j.span);
2192 binding_error.target.insert(p.span);
2194 Some(binding_i) => { // check consistent binding
2195 if binding_i.binding_mode != binding_j.binding_mode {
2198 .or_insert((binding_j.span, binding_i.span));
2206 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2207 missing_vars.sort();
2208 for (_, v) in missing_vars {
2210 *v.origin.iter().next().unwrap(),
2211 ResolutionError::VariableNotBoundInPattern(v));
2213 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2214 inconsistent_vars.sort();
2215 for (name, v) in inconsistent_vars {
2216 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2220 fn resolve_arm(&mut self, arm: &Arm) {
2221 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2223 let mut bindings_list = FxHashMap();
2224 for pattern in &arm.pats {
2225 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2228 // This has to happen *after* we determine which
2229 // pat_idents are variants
2230 self.check_consistent_bindings(arm);
2232 walk_list!(self, visit_expr, &arm.guard);
2233 self.visit_expr(&arm.body);
2235 self.ribs[ValueNS].pop();
2238 fn resolve_block(&mut self, block: &Block) {
2239 debug!("(resolving block) entering block");
2240 // Move down in the graph, if there's an anonymous module rooted here.
2241 let orig_module = self.current_module;
2242 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2244 let mut num_macro_definition_ribs = 0;
2245 if let Some(anonymous_module) = anonymous_module {
2246 debug!("(resolving block) found anonymous module, moving down");
2247 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2248 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2249 self.current_module = anonymous_module;
2250 self.finalize_current_module_macro_resolutions();
2252 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2255 // Descend into the block.
2256 for stmt in &block.stmts {
2257 if let ast::StmtKind::Item(ref item) = stmt.node {
2258 if let ast::ItemKind::MacroDef(..) = item.node {
2259 num_macro_definition_ribs += 1;
2260 let def = self.definitions.local_def_id(item.id);
2261 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2262 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2266 self.visit_stmt(stmt);
2270 self.current_module = orig_module;
2271 for _ in 0 .. num_macro_definition_ribs {
2272 self.ribs[ValueNS].pop();
2273 self.label_ribs.pop();
2275 self.ribs[ValueNS].pop();
2276 if let Some(_) = anonymous_module {
2277 self.ribs[TypeNS].pop();
2279 debug!("(resolving block) leaving block");
2282 fn fresh_binding(&mut self,
2283 ident: &SpannedIdent,
2285 outer_pat_id: NodeId,
2286 pat_src: PatternSource,
2287 bindings: &mut FxHashMap<Ident, NodeId>)
2289 // Add the binding to the local ribs, if it
2290 // doesn't already exist in the bindings map. (We
2291 // must not add it if it's in the bindings map
2292 // because that breaks the assumptions later
2293 // passes make about or-patterns.)
2294 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2295 match bindings.get(&ident.node).cloned() {
2296 Some(id) if id == outer_pat_id => {
2297 // `Variant(a, a)`, error
2301 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2302 &ident.node.name.as_str())
2305 Some(..) if pat_src == PatternSource::FnParam => {
2306 // `fn f(a: u8, a: u8)`, error
2310 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2311 &ident.node.name.as_str())
2314 Some(..) if pat_src == PatternSource::Match => {
2315 // `Variant1(a) | Variant2(a)`, ok
2316 // Reuse definition from the first `a`.
2317 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2320 span_bug!(ident.span, "two bindings with the same name from \
2321 unexpected pattern source {:?}", pat_src);
2324 // A completely fresh binding, add to the lists if it's valid.
2325 if ident.node.name != keywords::Invalid.name() {
2326 bindings.insert(ident.node, outer_pat_id);
2327 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2332 PathResolution::new(def)
2335 fn resolve_pattern(&mut self,
2337 pat_src: PatternSource,
2338 // Maps idents to the node ID for the
2339 // outermost pattern that binds them.
2340 bindings: &mut FxHashMap<Ident, NodeId>) {
2341 // Visit all direct subpatterns of this pattern.
2342 let outer_pat_id = pat.id;
2343 pat.walk(&mut |pat| {
2345 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2346 // First try to resolve the identifier as some existing
2347 // entity, then fall back to a fresh binding.
2348 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2350 .and_then(LexicalScopeBinding::item);
2351 let resolution = binding.map(NameBinding::def).and_then(|def| {
2352 let ivmode = BindingMode::ByValue(Mutability::Immutable);
2353 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2356 Def::StructCtor(_, CtorKind::Const) |
2357 Def::VariantCtor(_, CtorKind::Const) |
2358 Def::Const(..) if !always_binding => {
2359 // A unit struct/variant or constant pattern.
2360 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2361 Some(PathResolution::new(def))
2363 Def::StructCtor(..) | Def::VariantCtor(..) |
2364 Def::Const(..) | Def::Static(..) => {
2365 // A fresh binding that shadows something unacceptable.
2369 ResolutionError::BindingShadowsSomethingUnacceptable(
2370 pat_src.descr(), ident.node.name, binding.unwrap())
2374 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2375 // These entities are explicitly allowed
2376 // to be shadowed by fresh bindings.
2380 span_bug!(ident.span, "unexpected definition for an \
2381 identifier in pattern: {:?}", def);
2384 }).unwrap_or_else(|| {
2385 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2388 self.record_def(pat.id, resolution);
2391 PatKind::TupleStruct(ref path, ..) => {
2392 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2395 PatKind::Path(ref qself, ref path) => {
2396 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2399 PatKind::Struct(ref path, ..) => {
2400 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2408 visit::walk_pat(self, pat);
2411 // High-level and context dependent path resolution routine.
2412 // Resolves the path and records the resolution into definition map.
2413 // If resolution fails tries several techniques to find likely
2414 // resolution candidates, suggest imports or other help, and report
2415 // errors in user friendly way.
2416 fn smart_resolve_path(&mut self,
2418 qself: Option<&QSelf>,
2422 let segments = &path.segments.iter()
2423 .map(|seg| respan(seg.span, seg.identifier))
2424 .collect::<Vec<_>>();
2425 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2426 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2429 fn smart_resolve_path_fragment(&mut self,
2431 qself: Option<&QSelf>,
2432 path: &[SpannedIdent],
2437 let ns = source.namespace();
2438 let is_expected = &|def| source.is_expected(def);
2439 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2441 // Base error is amended with one short label and possibly some longer helps/notes.
2442 let report_errors = |this: &mut Self, def: Option<Def>| {
2443 // Make the base error.
2444 let expected = source.descr_expected();
2445 let path_str = names_to_string(path);
2446 let code = source.error_code(def.is_some());
2447 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2448 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2449 format!("not a {}", expected), span)
2451 let item_str = path[path.len() - 1].node;
2452 let item_span = path[path.len() - 1].span;
2453 let (mod_prefix, mod_str) = if path.len() == 1 {
2454 (format!(""), format!("this scope"))
2455 } else if path.len() == 2 && path[0].node.name == keywords::CrateRoot.name() {
2456 (format!(""), format!("the crate root"))
2458 let mod_path = &path[..path.len() - 1];
2459 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2460 PathResult::Module(module) => module.def(),
2462 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2463 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2465 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2466 format!("not found in {}", mod_str), item_span)
2468 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2470 // Emit special messages for unresolved `Self` and `self`.
2471 if is_self_type(path, ns) {
2472 __diagnostic_used!(E0411);
2473 err.code("E0411".into());
2474 err.span_label(span, "`Self` is only available in traits and impls");
2475 return (err, Vec::new());
2477 if is_self_value(path, ns) {
2478 __diagnostic_used!(E0424);
2479 err.code("E0424".into());
2480 err.span_label(span, format!("`self` value is only available in \
2481 methods with `self` parameter"));
2482 return (err, Vec::new());
2485 // Try to lookup the name in more relaxed fashion for better error reporting.
2486 let ident = *path.last().unwrap();
2487 let candidates = this.lookup_import_candidates(ident.node.name, ns, is_expected);
2488 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2489 let enum_candidates =
2490 this.lookup_import_candidates(ident.node.name, ns, is_enum_variant);
2491 let mut enum_candidates = enum_candidates.iter()
2492 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2493 enum_candidates.sort();
2494 for (sp, variant_path, enum_path) in enum_candidates {
2496 let msg = format!("there is an enum variant `{}`, \
2502 err.span_suggestion(span, "you can try using the variant's enum",
2507 if path.len() == 1 && this.self_type_is_available(span) {
2508 if let Some(candidate) = this.lookup_assoc_candidate(ident.node, ns, is_expected) {
2509 let self_is_available = this.self_value_is_available(path[0].node.ctxt, span);
2511 AssocSuggestion::Field => {
2512 err.span_suggestion(span, "try",
2513 format!("self.{}", path_str));
2514 if !self_is_available {
2515 err.span_label(span, format!("`self` value is only available in \
2516 methods with `self` parameter"));
2519 AssocSuggestion::MethodWithSelf if self_is_available => {
2520 err.span_suggestion(span, "try",
2521 format!("self.{}", path_str));
2523 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2524 err.span_suggestion(span, "try",
2525 format!("Self::{}", path_str));
2528 return (err, candidates);
2532 let mut levenshtein_worked = false;
2535 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2536 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2537 levenshtein_worked = true;
2540 // Try context dependent help if relaxed lookup didn't work.
2541 if let Some(def) = def {
2542 match (def, source) {
2543 (Def::Macro(..), _) => {
2544 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2545 return (err, candidates);
2547 (Def::TyAlias(..), PathSource::Trait) => {
2548 err.span_label(span, "type aliases cannot be used for traits");
2549 return (err, candidates);
2551 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2552 ExprKind::Field(_, ident) => {
2553 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2554 path_str, ident.node));
2555 return (err, candidates);
2557 ExprKind::MethodCall(ref segment, ..) => {
2558 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2559 path_str, segment.identifier));
2560 return (err, candidates);
2564 _ if ns == ValueNS && is_struct_like(def) => {
2565 if let Def::Struct(def_id) = def {
2566 if let Some((ctor_def, ctor_vis))
2567 = this.struct_constructors.get(&def_id).cloned() {
2568 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2569 err.span_label(span, format!("constructor is not visible \
2570 here due to private fields"));
2574 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2576 return (err, candidates);
2583 if !levenshtein_worked {
2584 err.span_label(base_span, fallback_label);
2585 this.type_ascription_suggestion(&mut err, base_span);
2589 let report_errors = |this: &mut Self, def: Option<Def>| {
2590 let (err, candidates) = report_errors(this, def);
2591 let def_id = this.current_module.normal_ancestor_id;
2592 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
2593 let better = def.is_some();
2594 this.use_injections.push(UseError { err, candidates, node_id, better });
2595 err_path_resolution()
2598 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2599 source.defer_to_typeck(),
2600 source.global_by_default()) {
2601 Some(resolution) if resolution.unresolved_segments() == 0 => {
2602 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2605 // Add a temporary hack to smooth the transition to new struct ctor
2606 // visibility rules. See #38932 for more details.
2608 if let Def::Struct(def_id) = resolution.base_def() {
2609 if let Some((ctor_def, ctor_vis))
2610 = self.struct_constructors.get(&def_id).cloned() {
2611 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2612 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2613 self.session.buffer_lint(lint, id, span,
2614 "private struct constructors are not usable through \
2615 reexports in outer modules",
2617 res = Some(PathResolution::new(ctor_def));
2622 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2625 Some(resolution) if source.defer_to_typeck() => {
2626 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2627 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2628 // it needs to be added to the trait map.
2630 let item_name = path.last().unwrap().node;
2631 let traits = self.get_traits_containing_item(item_name, ns);
2632 self.trait_map.insert(id, traits);
2636 _ => report_errors(self, None)
2639 if let PathSource::TraitItem(..) = source {} else {
2640 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2641 self.record_def(id, resolution);
2646 fn type_ascription_suggestion(&self,
2647 err: &mut DiagnosticBuilder,
2649 debug!("type_ascription_suggetion {:?}", base_span);
2650 let cm = self.session.codemap();
2651 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
2652 if let Some(sp) = self.current_type_ascription.last() {
2654 loop { // try to find the `:`, bail on first non-':'/non-whitespace
2655 sp = sp.next_point();
2656 if let Ok(snippet) = cm.span_to_snippet(sp.to(sp.next_point())) {
2657 debug!("snippet {:?}", snippet);
2658 let line_sp = cm.lookup_char_pos(sp.hi()).line;
2659 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
2660 debug!("{:?} {:?}", line_sp, line_base_sp);
2662 err.span_label(base_span,
2663 "expecting a type here because of type ascription");
2664 if line_sp != line_base_sp {
2665 err.span_suggestion_short(sp,
2666 "did you mean to use `;` here instead?",
2670 } else if snippet.trim().len() != 0 {
2671 debug!("tried to find type ascription `:` token, couldn't find it");
2681 fn self_type_is_available(&mut self, span: Span) -> bool {
2682 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2683 TypeNS, false, span);
2684 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2687 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2688 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2689 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2690 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2693 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2694 fn resolve_qpath_anywhere(&mut self,
2696 qself: Option<&QSelf>,
2697 path: &[SpannedIdent],
2698 primary_ns: Namespace,
2700 defer_to_typeck: bool,
2701 global_by_default: bool)
2702 -> Option<PathResolution> {
2703 let mut fin_res = None;
2704 // FIXME: can't resolve paths in macro namespace yet, macros are
2705 // processed by the little special hack below.
2706 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2707 if i == 0 || ns != primary_ns {
2708 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2709 // If defer_to_typeck, then resolution > no resolution,
2710 // otherwise full resolution > partial resolution > no resolution.
2711 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2713 res => if fin_res.is_none() { fin_res = res },
2717 let is_global = self.global_macros.get(&path[0].node.name).cloned()
2718 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2719 if primary_ns != MacroNS && (is_global ||
2720 self.macro_names.contains(&path[0].node.modern())) {
2721 // Return some dummy definition, it's enough for error reporting.
2723 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2729 /// Handles paths that may refer to associated items.
2730 fn resolve_qpath(&mut self,
2732 qself: Option<&QSelf>,
2733 path: &[SpannedIdent],
2736 global_by_default: bool)
2737 -> Option<PathResolution> {
2738 if let Some(qself) = qself {
2739 if qself.position == 0 {
2740 // FIXME: Create some fake resolution that can't possibly be a type.
2741 return Some(PathResolution::with_unresolved_segments(
2742 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2745 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2746 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2747 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2748 span, span, PathSource::TraitItem(ns));
2749 return Some(PathResolution::with_unresolved_segments(
2750 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2754 let result = match self.resolve_path(&path, Some(ns), true, span) {
2755 PathResult::NonModule(path_res) => path_res,
2756 PathResult::Module(module) if !module.is_normal() => {
2757 PathResolution::new(module.def().unwrap())
2759 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2760 // don't report an error right away, but try to fallback to a primitive type.
2761 // So, we are still able to successfully resolve something like
2763 // use std::u8; // bring module u8 in scope
2764 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2765 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2766 // // not to non-existent std::u8::max_value
2769 // Such behavior is required for backward compatibility.
2770 // The same fallback is used when `a` resolves to nothing.
2771 PathResult::Module(..) | PathResult::Failed(..)
2772 if (ns == TypeNS || path.len() > 1) &&
2773 self.primitive_type_table.primitive_types
2774 .contains_key(&path[0].node.name) => {
2775 let prim = self.primitive_type_table.primitive_types[&path[0].node.name];
2777 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2778 if !self.session.features.borrow().i128_type {
2779 emit_feature_err(&self.session.parse_sess,
2780 "i128_type", span, GateIssue::Language,
2781 "128-bit type is unstable");
2787 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2789 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2790 PathResult::Failed(span, msg, false) => {
2791 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2792 err_path_resolution()
2794 PathResult::Failed(..) => return None,
2795 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2798 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2799 path[0].node.name != keywords::CrateRoot.name() &&
2800 path[0].node.name != keywords::DollarCrate.name() {
2801 let unqualified_result = {
2802 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2803 PathResult::NonModule(path_res) => path_res.base_def(),
2804 PathResult::Module(module) => module.def().unwrap(),
2805 _ => return Some(result),
2808 if result.base_def() == unqualified_result {
2809 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2810 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
2817 fn resolve_path(&mut self,
2818 path: &[SpannedIdent],
2819 opt_ns: Option<Namespace>, // `None` indicates a module path
2823 let mut module = None;
2824 let mut allow_super = true;
2826 for (i, &ident) in path.iter().enumerate() {
2827 debug!("resolve_path ident {} {:?}", i, ident);
2828 let is_last = i == path.len() - 1;
2829 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2831 if i == 0 && ns == TypeNS && ident.node.name == keywords::SelfValue.name() {
2832 let mut ctxt = ident.node.ctxt.modern();
2833 module = Some(self.resolve_self(&mut ctxt, self.current_module));
2835 } else if allow_super && ns == TypeNS && ident.node.name == keywords::Super.name() {
2836 let mut ctxt = ident.node.ctxt.modern();
2837 let self_module = match i {
2838 0 => self.resolve_self(&mut ctxt, self.current_module),
2839 _ => module.unwrap(),
2841 if let Some(parent) = self_module.parent {
2842 module = Some(self.resolve_self(&mut ctxt, parent));
2845 let msg = "There are too many initial `super`s.".to_string();
2846 return PathResult::Failed(ident.span, msg, false);
2849 allow_super = false;
2851 if i == 0 && ns == TypeNS && ident.node.name == keywords::CrateRoot.name() {
2852 module = Some(self.resolve_crate_root(ident.node.ctxt.modern()));
2854 } else if i == 0 && ns == TypeNS && ident.node.name == keywords::DollarCrate.name() {
2855 module = Some(self.resolve_crate_root(ident.node.ctxt));
2859 let binding = if let Some(module) = module {
2860 self.resolve_ident_in_module(module, ident.node, ns, false, record_used, path_span)
2861 } else if opt_ns == Some(MacroNS) {
2862 self.resolve_lexical_macro_path_segment(ident.node, ns, record_used, path_span)
2863 .map(MacroBinding::binding)
2865 match self.resolve_ident_in_lexical_scope(ident.node, ns, record_used, path_span) {
2866 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2867 Some(LexicalScopeBinding::Def(def))
2868 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2869 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2873 _ => Err(if record_used { Determined } else { Undetermined }),
2879 let def = binding.def();
2880 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2881 if let Some(next_module) = binding.module() {
2882 module = Some(next_module);
2883 } else if def == Def::Err {
2884 return PathResult::NonModule(err_path_resolution());
2885 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2886 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2887 def, path.len() - i - 1
2890 return PathResult::Failed(ident.span,
2891 format!("Not a module `{}`", ident.node),
2895 Err(Undetermined) => return PathResult::Indeterminate,
2896 Err(Determined) => {
2897 if let Some(module) = module {
2898 if opt_ns.is_some() && !module.is_normal() {
2899 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2900 module.def().unwrap(), path.len() - i
2904 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2905 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2906 let mut candidates =
2907 self.lookup_import_candidates(ident.node.name, TypeNS, is_mod);
2908 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2909 if let Some(candidate) = candidates.get(0) {
2910 format!("Did you mean `{}`?", candidate.path)
2912 format!("Maybe a missing `extern crate {};`?", ident.node)
2915 format!("Use of undeclared type or module `{}`", ident.node)
2917 format!("Could not find `{}` in `{}`", ident.node, path[i - 1].node)
2919 return PathResult::Failed(ident.span, msg, is_last);
2924 PathResult::Module(module.unwrap_or(self.graph_root))
2927 // Resolve a local definition, potentially adjusting for closures.
2928 fn adjust_local_def(&mut self,
2933 span: Span) -> Def {
2934 let ribs = &self.ribs[ns][rib_index + 1..];
2936 // An invalid forward use of a type parameter from a previous default.
2937 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2939 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
2941 assert_eq!(def, Def::Err);
2947 span_bug!(span, "unexpected {:?} in bindings", def)
2949 Def::Local(def_id) => {
2952 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2953 ForwardTyParamBanRibKind => {
2954 // Nothing to do. Continue.
2956 ClosureRibKind(function_id) => {
2958 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2960 let seen = self.freevars_seen
2962 .or_insert_with(|| NodeMap());
2963 if let Some(&index) = seen.get(&node_id) {
2964 def = Def::Upvar(def_id, index, function_id);
2967 let vec = self.freevars
2969 .or_insert_with(|| vec![]);
2970 let depth = vec.len();
2971 def = Def::Upvar(def_id, depth, function_id);
2978 seen.insert(node_id, depth);
2981 ItemRibKind | MethodRibKind(_) => {
2982 // This was an attempt to access an upvar inside a
2983 // named function item. This is not allowed, so we
2986 resolve_error(self, span,
2987 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2991 ConstantItemRibKind => {
2992 // Still doesn't deal with upvars
2994 resolve_error(self, span,
2995 ResolutionError::AttemptToUseNonConstantValueInConstant);
3002 Def::TyParam(..) | Def::SelfTy(..) => {
3005 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
3006 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3007 ConstantItemRibKind => {
3008 // Nothing to do. Continue.
3011 // This was an attempt to use a type parameter outside
3014 resolve_error(self, span,
3015 ResolutionError::TypeParametersFromOuterFunction);
3027 fn lookup_assoc_candidate<FilterFn>(&mut self,
3030 filter_fn: FilterFn)
3031 -> Option<AssocSuggestion>
3032 where FilterFn: Fn(Def) -> bool
3034 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3036 TyKind::Path(None, _) => Some(t.id),
3037 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3038 // This doesn't handle the remaining `Ty` variants as they are not
3039 // that commonly the self_type, it might be interesting to provide
3040 // support for those in future.
3045 // Fields are generally expected in the same contexts as locals.
3046 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
3047 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3048 // Look for a field with the same name in the current self_type.
3049 if let Some(resolution) = self.def_map.get(&node_id) {
3050 match resolution.base_def() {
3051 Def::Struct(did) | Def::Union(did)
3052 if resolution.unresolved_segments() == 0 => {
3053 if let Some(field_names) = self.field_names.get(&did) {
3054 if field_names.iter().any(|&field_name| ident.name == field_name) {
3055 return Some(AssocSuggestion::Field);
3065 // Look for associated items in the current trait.
3066 if let Some((module, _)) = self.current_trait_ref {
3067 if let Ok(binding) =
3068 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3069 let def = binding.def();
3071 return Some(if self.has_self.contains(&def.def_id()) {
3072 AssocSuggestion::MethodWithSelf
3074 AssocSuggestion::AssocItem
3083 fn lookup_typo_candidate<FilterFn>(&mut self,
3084 path: &[SpannedIdent],
3086 filter_fn: FilterFn,
3089 where FilterFn: Fn(Def) -> bool
3091 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3092 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3093 if let Some(binding) = resolution.borrow().binding {
3094 if filter_fn(binding.def()) {
3095 names.push(ident.name);
3101 let mut names = Vec::new();
3102 if path.len() == 1 {
3103 // Search in lexical scope.
3104 // Walk backwards up the ribs in scope and collect candidates.
3105 for rib in self.ribs[ns].iter().rev() {
3106 // Locals and type parameters
3107 for (ident, def) in &rib.bindings {
3108 if filter_fn(*def) {
3109 names.push(ident.name);
3113 if let ModuleRibKind(module) = rib.kind {
3114 // Items from this module
3115 add_module_candidates(module, &mut names);
3117 if let ModuleKind::Block(..) = module.kind {
3118 // We can see through blocks
3120 // Items from the prelude
3121 if let Some(prelude) = self.prelude {
3122 if !module.no_implicit_prelude {
3123 add_module_candidates(prelude, &mut names);
3130 // Add primitive types to the mix
3131 if filter_fn(Def::PrimTy(TyBool)) {
3132 for (name, _) in &self.primitive_type_table.primitive_types {
3137 // Search in module.
3138 let mod_path = &path[..path.len() - 1];
3139 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3141 add_module_candidates(module, &mut names);
3145 let name = path[path.len() - 1].node.name;
3146 // Make sure error reporting is deterministic.
3147 names.sort_by_key(|name| name.as_str());
3148 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3149 Some(found) if found != name => Some(found),
3154 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
3155 where F: FnOnce(&mut Resolver)
3157 if let Some(label) = label {
3158 let def = Def::Label(id);
3159 self.with_label_rib(|this| {
3160 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
3168 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
3169 self.with_resolved_label(label, id, |this| this.visit_block(block));
3172 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3173 // First, record candidate traits for this expression if it could
3174 // result in the invocation of a method call.
3176 self.record_candidate_traits_for_expr_if_necessary(expr);
3178 // Next, resolve the node.
3180 ExprKind::Path(ref qself, ref path) => {
3181 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3182 visit::walk_expr(self, expr);
3185 ExprKind::Struct(ref path, ..) => {
3186 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3187 visit::walk_expr(self, expr);
3190 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3191 match self.search_label(label.node) {
3193 self.record_def(expr.id, err_path_resolution());
3196 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
3198 Some(def @ Def::Label(_)) => {
3199 // Since this def is a label, it is never read.
3200 self.record_def(expr.id, PathResolution::new(def));
3203 span_bug!(expr.span, "label wasn't mapped to a label def!");
3207 // visit `break` argument if any
3208 visit::walk_expr(self, expr);
3211 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
3212 self.visit_expr(subexpression);
3214 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3215 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
3216 self.visit_block(if_block);
3217 self.ribs[ValueNS].pop();
3219 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3222 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3224 ExprKind::While(ref subexpression, ref block, label) => {
3225 self.with_resolved_label(label, expr.id, |this| {
3226 this.visit_expr(subexpression);
3227 this.visit_block(block);
3231 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3232 self.with_resolved_label(label, expr.id, |this| {
3233 this.visit_expr(subexpression);
3234 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3235 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3236 this.visit_block(block);
3237 this.ribs[ValueNS].pop();
3241 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3242 self.visit_expr(subexpression);
3243 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3244 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3246 self.resolve_labeled_block(label, expr.id, block);
3248 self.ribs[ValueNS].pop();
3251 // Equivalent to `visit::walk_expr` + passing some context to children.
3252 ExprKind::Field(ref subexpression, _) => {
3253 self.resolve_expr(subexpression, Some(expr));
3255 ExprKind::MethodCall(ref segment, ref arguments) => {
3256 let mut arguments = arguments.iter();
3257 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3258 for argument in arguments {
3259 self.resolve_expr(argument, None);
3261 self.visit_path_segment(expr.span, segment);
3264 ExprKind::Repeat(ref element, ref count) => {
3265 self.visit_expr(element);
3266 self.with_constant_rib(|this| {
3267 this.visit_expr(count);
3270 ExprKind::Call(ref callee, ref arguments) => {
3271 self.resolve_expr(callee, Some(expr));
3272 for argument in arguments {
3273 self.resolve_expr(argument, None);
3276 ExprKind::Type(ref type_expr, _) => {
3277 self.current_type_ascription.push(type_expr.span);
3278 visit::walk_expr(self, expr);
3279 self.current_type_ascription.pop();
3282 visit::walk_expr(self, expr);
3287 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3289 ExprKind::Field(_, name) => {
3290 // FIXME(#6890): Even though you can't treat a method like a
3291 // field, we need to add any trait methods we find that match
3292 // the field name so that we can do some nice error reporting
3293 // later on in typeck.
3294 let traits = self.get_traits_containing_item(name.node, ValueNS);
3295 self.trait_map.insert(expr.id, traits);
3297 ExprKind::MethodCall(ref segment, ..) => {
3298 debug!("(recording candidate traits for expr) recording traits for {}",
3300 let traits = self.get_traits_containing_item(segment.identifier, ValueNS);
3301 self.trait_map.insert(expr.id, traits);
3309 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
3310 -> Vec<TraitCandidate> {
3311 debug!("(getting traits containing item) looking for '{}'", ident.name);
3313 let mut found_traits = Vec::new();
3314 // Look for the current trait.
3315 if let Some((module, _)) = self.current_trait_ref {
3316 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3317 let def_id = module.def_id().unwrap();
3318 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3322 ident.ctxt = ident.ctxt.modern();
3323 let mut search_module = self.current_module;
3325 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3327 unwrap_or!(self.hygienic_lexical_parent(search_module, &mut ident.ctxt), break);
3330 if let Some(prelude) = self.prelude {
3331 if !search_module.no_implicit_prelude {
3332 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3339 fn get_traits_in_module_containing_item(&mut self,
3343 found_traits: &mut Vec<TraitCandidate>) {
3344 let mut traits = module.traits.borrow_mut();
3345 if traits.is_none() {
3346 let mut collected_traits = Vec::new();
3347 module.for_each_child(|name, ns, binding| {
3348 if ns != TypeNS { return }
3349 if let Def::Trait(_) = binding.def() {
3350 collected_traits.push((name, binding));
3353 *traits = Some(collected_traits.into_boxed_slice());
3356 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3357 let module = binding.module().unwrap();
3358 let mut ident = ident;
3359 if ident.ctxt.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
3362 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
3364 let import_id = match binding.kind {
3365 NameBindingKind::Import { directive, .. } => {
3366 self.maybe_unused_trait_imports.insert(directive.id);
3367 self.add_to_glob_map(directive.id, trait_name);
3372 let trait_def_id = module.def_id().unwrap();
3373 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3378 /// When name resolution fails, this method can be used to look up candidate
3379 /// entities with the expected name. It allows filtering them using the
3380 /// supplied predicate (which should be used to only accept the types of
3381 /// definitions expected e.g. traits). The lookup spans across all crates.
3383 /// NOTE: The method does not look into imports, but this is not a problem,
3384 /// since we report the definitions (thus, the de-aliased imports).
3385 fn lookup_import_candidates<FilterFn>(&mut self,
3387 namespace: Namespace,
3388 filter_fn: FilterFn)
3389 -> Vec<ImportSuggestion>
3390 where FilterFn: Fn(Def) -> bool
3392 let mut candidates = Vec::new();
3393 let mut worklist = Vec::new();
3394 let mut seen_modules = FxHashSet();
3395 worklist.push((self.graph_root, Vec::new(), false));
3397 while let Some((in_module,
3399 in_module_is_extern)) = worklist.pop() {
3400 self.populate_module_if_necessary(in_module);
3402 // We have to visit module children in deterministic order to avoid
3403 // instabilities in reported imports (#43552).
3404 in_module.for_each_child_stable(|ident, ns, name_binding| {
3405 // avoid imports entirely
3406 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3407 // avoid non-importable candidates as well
3408 if !name_binding.is_importable() { return; }
3410 // collect results based on the filter function
3411 if ident.name == lookup_name && ns == namespace {
3412 if filter_fn(name_binding.def()) {
3414 let mut segms = path_segments.clone();
3415 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3417 span: name_binding.span,
3420 // the entity is accessible in the following cases:
3421 // 1. if it's defined in the same crate, it's always
3422 // accessible (since private entities can be made public)
3423 // 2. if it's defined in another crate, it's accessible
3424 // only if both the module is public and the entity is
3425 // declared as public (due to pruning, we don't explore
3426 // outside crate private modules => no need to check this)
3427 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3428 candidates.push(ImportSuggestion { path: path });
3433 // collect submodules to explore
3434 if let Some(module) = name_binding.module() {
3436 let mut path_segments = path_segments.clone();
3437 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3439 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3440 // add the module to the lookup
3441 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3442 if seen_modules.insert(module.def_id().unwrap()) {
3443 worklist.push((module, path_segments, is_extern));
3453 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3454 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3455 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3456 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3460 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3462 ast::Visibility::Public => ty::Visibility::Public,
3463 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3464 ast::Visibility::Inherited => {
3465 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3467 ast::Visibility::Restricted { ref path, id } => {
3468 let def = self.smart_resolve_path(id, None, path,
3469 PathSource::Visibility).base_def();
3470 if def == Def::Err {
3471 ty::Visibility::Public
3473 let vis = ty::Visibility::Restricted(def.def_id());
3474 if self.is_accessible(vis) {
3477 self.session.span_err(path.span, "visibilities can only be restricted \
3478 to ancestor modules");
3479 ty::Visibility::Public
3486 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3487 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3490 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3491 vis.is_accessible_from(module.normal_ancestor_id, self)
3494 fn report_errors(&mut self, krate: &Crate) {
3495 self.report_shadowing_errors();
3496 self.report_with_use_injections(krate);
3497 let mut reported_spans = FxHashSet();
3499 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3500 if !reported_spans.insert(span) { continue }
3501 let participle = |binding: &NameBinding| {
3502 if binding.is_import() { "imported" } else { "defined" }
3504 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3505 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3506 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3507 format!("consider adding an explicit import of `{}` to disambiguate", name)
3508 } else if let Def::Macro(..) = b1.def() {
3509 format!("macro-expanded {} do not shadow",
3510 if b1.is_import() { "macro imports" } else { "macros" })
3512 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3513 if b1.is_import() { "imports" } else { "items" })
3516 let id = match b2.kind {
3517 NameBindingKind::Import { directive, .. } => directive.id,
3518 _ => unreachable!(),
3520 let mut span = MultiSpan::from_span(span);
3521 span.push_span_label(b1.span, msg1);
3522 span.push_span_label(b2.span, msg2);
3523 let msg = format!("`{}` is ambiguous", name);
3524 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, &msg);
3527 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3528 err.span_note(b1.span, &msg1);
3530 Def::Macro(..) if b2.span == DUMMY_SP =>
3531 err.note(&format!("`{}` is also a builtin macro", name)),
3532 _ => err.span_note(b2.span, &msg2),
3534 err.note(¬e).emit();
3538 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3539 if !reported_spans.insert(span) { continue }
3540 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
3544 fn report_with_use_injections(&mut self, krate: &Crate) {
3545 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
3546 let mut finder = UsePlacementFinder {
3547 target_module: node_id,
3551 visit::walk_crate(&mut finder, krate);
3552 if !candidates.is_empty() {
3553 let span = finder.span.expect("did not find module");
3554 show_candidates(&mut err, span, &candidates, better, finder.found_use);
3560 fn report_shadowing_errors(&mut self) {
3561 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3562 self.resolve_legacy_scope(scope, ident, true);
3565 let mut reported_errors = FxHashSet();
3566 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3567 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
3568 reported_errors.insert((binding.ident, binding.span)) {
3569 let msg = format!("`{}` is already in scope", binding.ident);
3570 self.session.struct_span_err(binding.span, &msg)
3571 .note("macro-expanded `macro_rules!`s may not shadow \
3572 existing macros (see RFC 1560)")
3578 fn report_conflict(&mut self,
3582 new_binding: &NameBinding,
3583 old_binding: &NameBinding) {
3584 // Error on the second of two conflicting names
3585 if old_binding.span.lo() > new_binding.span.lo() {
3586 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3589 let container = match parent.kind {
3590 ModuleKind::Def(Def::Mod(_), _) => "module",
3591 ModuleKind::Def(Def::Trait(_), _) => "trait",
3592 ModuleKind::Block(..) => "block",
3596 let old_noun = match old_binding.is_import() {
3598 false => "definition",
3601 let new_participle = match new_binding.is_import() {
3606 let (name, span) = (ident.name, new_binding.span);
3608 if let Some(s) = self.name_already_seen.get(&name) {
3614 let old_kind = match (ns, old_binding.module()) {
3615 (ValueNS, _) => "value",
3616 (MacroNS, _) => "macro",
3617 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3618 (TypeNS, Some(module)) if module.is_normal() => "module",
3619 (TypeNS, Some(module)) if module.is_trait() => "trait",
3620 (TypeNS, _) => "type",
3623 let namespace = match ns {
3629 let msg = format!("the name `{}` is defined multiple times", name);
3631 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3632 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3633 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3634 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3635 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3637 _ => match (old_binding.is_import(), new_binding.is_import()) {
3638 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3639 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3640 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3644 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
3649 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3650 if old_binding.span != syntax_pos::DUMMY_SP {
3651 err.span_label(old_binding.span, format!("previous {} of the {} `{}` here",
3652 old_noun, old_kind, name));
3656 self.name_already_seen.insert(name, span);
3659 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3660 let (id, span) = (directive.id, directive.span);
3661 let msg = "`self` no longer imports values";
3662 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3665 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3666 if self.proc_macro_enabled { return; }
3669 if attr.path.segments.len() > 1 {
3672 let ident = attr.path.segments[0].identifier;
3673 let result = self.resolve_lexical_macro_path_segment(ident,
3677 if let Ok(binding) = result {
3678 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3679 attr::mark_known(attr);
3681 let msg = "attribute procedural macros are experimental";
3682 let feature = "proc_macro";
3684 feature_err(&self.session.parse_sess, feature,
3685 attr.span, GateIssue::Language, msg)
3686 .span_note(binding.span(), "procedural macro imported here")
3694 fn is_struct_like(def: Def) -> bool {
3696 Def::VariantCtor(_, CtorKind::Fictive) => true,
3697 _ => PathSource::Struct.is_expected(def),
3701 fn is_self_type(path: &[SpannedIdent], namespace: Namespace) -> bool {
3702 namespace == TypeNS && path.len() == 1 && path[0].node.name == keywords::SelfType.name()
3705 fn is_self_value(path: &[SpannedIdent], namespace: Namespace) -> bool {
3706 namespace == ValueNS && path.len() == 1 && path[0].node.name == keywords::SelfValue.name()
3709 fn names_to_string(idents: &[SpannedIdent]) -> String {
3710 let mut result = String::new();
3711 for (i, ident) in idents.iter()
3712 .filter(|i| i.node.name != keywords::CrateRoot.name())
3715 result.push_str("::");
3717 result.push_str(&ident.node.name.as_str());
3722 fn path_names_to_string(path: &Path) -> String {
3723 names_to_string(&path.segments.iter()
3724 .map(|seg| respan(seg.span, seg.identifier))
3725 .collect::<Vec<_>>())
3728 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3729 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3730 let variant_path = &suggestion.path;
3731 let variant_path_string = path_names_to_string(variant_path);
3733 let path_len = suggestion.path.segments.len();
3734 let enum_path = ast::Path {
3735 span: suggestion.path.span,
3736 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3738 let enum_path_string = path_names_to_string(&enum_path);
3740 (suggestion.path.span, variant_path_string, enum_path_string)
3744 /// When an entity with a given name is not available in scope, we search for
3745 /// entities with that name in all crates. This method allows outputting the
3746 /// results of this search in a programmer-friendly way
3747 fn show_candidates(err: &mut DiagnosticBuilder,
3749 candidates: &[ImportSuggestion],
3753 // we want consistent results across executions, but candidates are produced
3754 // by iterating through a hash map, so make sure they are ordered:
3755 let mut path_strings: Vec<_> =
3756 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3757 path_strings.sort();
3759 let better = if better { "better " } else { "" };
3760 let msg_diff = match path_strings.len() {
3761 1 => " is found in another module, you can import it",
3762 _ => "s are found in other modules, you can import them",
3764 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3766 for candidate in &mut path_strings {
3767 // produce an additional newline to separate the new use statement
3768 // from the directly following item.
3769 let additional_newline = if found_use {
3774 *candidate = format!("use {};\n{}", candidate, additional_newline);
3777 err.span_suggestions(span, &msg, path_strings);
3780 /// A somewhat inefficient routine to obtain the name of a module.
3781 fn module_to_string(module: Module) -> String {
3782 let mut names = Vec::new();
3784 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3785 if let ModuleKind::Def(_, name) = module.kind {
3786 if let Some(parent) = module.parent {
3787 names.push(Ident::with_empty_ctxt(name));
3788 collect_mod(names, parent);
3791 // danger, shouldn't be ident?
3792 names.push(Ident::from_str("<opaque>"));
3793 collect_mod(names, module.parent.unwrap());
3796 collect_mod(&mut names, module);
3798 if names.is_empty() {
3799 return "???".to_string();
3801 names_to_string(&names.into_iter()
3803 .map(|n| dummy_spanned(n))
3804 .collect::<Vec<_>>())
3807 fn err_path_resolution() -> PathResolution {
3808 PathResolution::new(Def::Err)
3811 #[derive(PartialEq,Copy, Clone)]
3812 pub enum MakeGlobMap {
3817 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }