1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![crate_name = "rustc_resolve"]
12 #![crate_type = "dylib"]
13 #![crate_type = "rlib"]
14 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
15 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
16 html_root_url = "https://doc.rust-lang.org/nightly/")]
19 #![feature(associated_consts)]
20 #![feature(rustc_diagnostic_macros)]
22 #![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
23 #![cfg_attr(stage0, feature(rustc_private))]
24 #![cfg_attr(stage0, feature(staged_api))]
30 extern crate syntax_pos;
31 extern crate rustc_errors as errors;
36 use self::Namespace::*;
37 use self::TypeParameters::*;
40 use rustc::hir::map::{Definitions, DefCollector};
41 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
42 use rustc::middle::cstore::CrateLoader;
43 use rustc::session::Session;
45 use rustc::hir::def::*;
46 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
48 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
49 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
51 use syntax::ext::hygiene::{Mark, SyntaxContext};
52 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
53 use syntax::ext::base::SyntaxExtension;
54 use syntax::ext::base::Determinacy::{Determined, Undetermined};
55 use syntax::ext::base::MacroKind;
56 use syntax::symbol::{Symbol, keywords};
57 use syntax::util::lev_distance::find_best_match_for_name;
59 use syntax::visit::{self, FnKind, Visitor};
61 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
62 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
63 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
64 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
65 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
66 use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
68 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
69 use errors::DiagnosticBuilder;
71 use std::cell::{Cell, RefCell};
73 use std::collections::BTreeSet;
75 use std::mem::replace;
78 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
79 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
81 // NB: This module needs to be declared first so diagnostics are
82 // registered before they are used.
87 mod build_reduced_graph;
90 /// A free importable items suggested in case of resolution failure.
91 struct ImportSuggestion {
95 /// A field or associated item from self type suggested in case of resolution failure.
96 enum AssocSuggestion {
103 struct BindingError {
105 origin: BTreeSet<Span>,
106 target: BTreeSet<Span>,
109 impl PartialOrd for BindingError {
110 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
111 Some(self.cmp(other))
115 impl PartialEq for BindingError {
116 fn eq(&self, other: &BindingError) -> bool {
117 self.name == other.name
121 impl Ord for BindingError {
122 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
123 self.name.cmp(&other.name)
127 enum ResolutionError<'a> {
128 /// error E0401: can't use type parameters from outer function
129 TypeParametersFromOuterFunction,
130 /// error E0402: cannot use an outer type parameter in this context
131 OuterTypeParameterContext,
132 /// error E0403: the name is already used for a type parameter in this type parameter list
133 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
134 /// error E0407: method is not a member of trait
135 MethodNotMemberOfTrait(Name, &'a str),
136 /// error E0437: type is not a member of trait
137 TypeNotMemberOfTrait(Name, &'a str),
138 /// error E0438: const is not a member of trait
139 ConstNotMemberOfTrait(Name, &'a str),
140 /// error E0408: variable `{}` is not bound in all patterns
141 VariableNotBoundInPattern(&'a BindingError),
142 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
143 VariableBoundWithDifferentMode(Name, Span),
144 /// error E0415: identifier is bound more than once in this parameter list
145 IdentifierBoundMoreThanOnceInParameterList(&'a str),
146 /// error E0416: identifier is bound more than once in the same pattern
147 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
148 /// error E0426: use of undeclared label
149 UndeclaredLabel(&'a str),
150 /// error E0429: `self` imports are only allowed within a { } list
151 SelfImportsOnlyAllowedWithin,
152 /// error E0430: `self` import can only appear once in the list
153 SelfImportCanOnlyAppearOnceInTheList,
154 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
155 SelfImportOnlyInImportListWithNonEmptyPrefix,
156 /// error E0432: unresolved import
157 UnresolvedImport(Option<(&'a str, &'a str)>),
158 /// error E0433: failed to resolve
159 FailedToResolve(&'a str),
160 /// error E0434: can't capture dynamic environment in a fn item
161 CannotCaptureDynamicEnvironmentInFnItem,
162 /// error E0435: attempt to use a non-constant value in a constant
163 AttemptToUseNonConstantValueInConstant,
164 /// error E0530: X bindings cannot shadow Ys
165 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
166 /// error E0128: type parameters with a default cannot use forward declared identifiers
167 ForwardDeclaredTyParam,
170 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
172 resolution_error: ResolutionError<'a>) {
173 resolve_struct_error(resolver, span, resolution_error).emit();
176 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
178 resolution_error: ResolutionError<'a>)
179 -> DiagnosticBuilder<'sess> {
180 match resolution_error {
181 ResolutionError::TypeParametersFromOuterFunction => {
182 let mut err = struct_span_err!(resolver.session,
185 "can't use type parameters from outer function; \
186 try using a local type parameter instead");
187 err.span_label(span, "use of type variable from outer function");
190 ResolutionError::OuterTypeParameterContext => {
191 struct_span_err!(resolver.session,
194 "cannot use an outer type parameter in this context")
196 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
197 let mut err = struct_span_err!(resolver.session,
200 "the name `{}` is already used for a type parameter \
201 in this type parameter list",
203 err.span_label(span, "already used");
204 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
207 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
208 let mut err = struct_span_err!(resolver.session,
211 "method `{}` is not a member of trait `{}`",
214 err.span_label(span, format!("not a member of trait `{}`", trait_));
217 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
218 let mut err = struct_span_err!(resolver.session,
221 "type `{}` is not a member of trait `{}`",
224 err.span_label(span, format!("not a member of trait `{}`", trait_));
227 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
228 let mut err = struct_span_err!(resolver.session,
231 "const `{}` is not a member of trait `{}`",
234 err.span_label(span, format!("not a member of trait `{}`", trait_));
237 ResolutionError::VariableNotBoundInPattern(binding_error) => {
238 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
239 let msp = MultiSpan::from_spans(target_sp.clone());
240 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
241 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
242 for sp in target_sp {
243 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
245 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
246 for sp in origin_sp {
247 err.span_label(sp, "variable not in all patterns");
251 ResolutionError::VariableBoundWithDifferentMode(variable_name,
252 first_binding_span) => {
253 let mut err = struct_span_err!(resolver.session,
256 "variable `{}` is bound in inconsistent \
257 ways within the same match arm",
259 err.span_label(span, "bound in different ways");
260 err.span_label(first_binding_span, "first binding");
263 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
264 let mut err = struct_span_err!(resolver.session,
267 "identifier `{}` is bound more than once in this parameter list",
269 err.span_label(span, "used as parameter more than once");
272 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
273 let mut err = struct_span_err!(resolver.session,
276 "identifier `{}` is bound more than once in the same pattern",
278 err.span_label(span, "used in a pattern more than once");
281 ResolutionError::UndeclaredLabel(name) => {
282 let mut err = struct_span_err!(resolver.session,
285 "use of undeclared label `{}`",
287 err.span_label(span, format!("undeclared label `{}`", name));
290 ResolutionError::SelfImportsOnlyAllowedWithin => {
291 struct_span_err!(resolver.session,
295 "`self` imports are only allowed within a { } list")
297 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
298 struct_span_err!(resolver.session,
301 "`self` import can only appear once in the list")
303 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
304 struct_span_err!(resolver.session,
307 "`self` import can only appear in an import list with a \
310 ResolutionError::UnresolvedImport(name) => {
311 let msg = match name {
312 Some((n, _)) => format!("unresolved import `{}`", n),
313 None => "unresolved import".to_owned(),
315 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
316 if let Some((_, p)) = name {
317 err.span_label(span, p);
321 ResolutionError::FailedToResolve(msg) => {
322 let mut err = struct_span_err!(resolver.session, span, E0433,
323 "failed to resolve. {}", msg);
324 err.span_label(span, msg);
327 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
328 struct_span_err!(resolver.session,
332 "can't capture dynamic environment in a fn item; use the || { ... } \
333 closure form instead")
335 ResolutionError::AttemptToUseNonConstantValueInConstant => {
336 let mut err = struct_span_err!(resolver.session,
339 "attempt to use a non-constant value in a constant");
340 err.span_label(span, "non-constant used with constant");
343 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
344 let shadows_what = PathResolution::new(binding.def()).kind_name();
345 let mut err = struct_span_err!(resolver.session,
348 "{}s cannot shadow {}s", what_binding, shadows_what);
349 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
350 let participle = if binding.is_import() { "imported" } else { "defined" };
351 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
352 err.span_label(binding.span, msg);
355 ResolutionError::ForwardDeclaredTyParam => {
356 let mut err = struct_span_err!(resolver.session, span, E0128,
357 "type parameters with a default cannot use \
358 forward declared identifiers");
359 err.span_label(span, format!("defaulted type parameters \
360 cannot be forward declared"));
366 #[derive(Copy, Clone, Debug)]
369 binding_mode: BindingMode,
372 // Map from the name in a pattern to its binding mode.
373 type BindingMap = FxHashMap<Ident, BindingInfo>;
375 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
386 fn is_refutable(self) -> bool {
388 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
389 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
392 fn descr(self) -> &'static str {
394 PatternSource::Match => "match binding",
395 PatternSource::IfLet => "if let binding",
396 PatternSource::WhileLet => "while let binding",
397 PatternSource::Let => "let binding",
398 PatternSource::For => "for binding",
399 PatternSource::FnParam => "function parameter",
404 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
405 enum PathSource<'a> {
406 // Type paths `Path`.
408 // Trait paths in bounds or impls.
410 // Expression paths `path`, with optional parent context.
411 Expr(Option<&'a Expr>),
412 // Paths in path patterns `Path`.
414 // Paths in struct expressions and patterns `Path { .. }`.
416 // Paths in tuple struct patterns `Path(..)`.
418 // `m::A::B` in `<T as m::A>::B::C`.
419 TraitItem(Namespace),
420 // Path in `pub(path)`
422 // Path in `use a::b::{...};`
426 impl<'a> PathSource<'a> {
427 fn namespace(self) -> Namespace {
429 PathSource::Type | PathSource::Trait | PathSource::Struct |
430 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
431 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
432 PathSource::TraitItem(ns) => ns,
436 fn global_by_default(self) -> bool {
438 PathSource::Visibility | PathSource::ImportPrefix => true,
439 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
440 PathSource::Struct | PathSource::TupleStruct |
441 PathSource::Trait | PathSource::TraitItem(..) => false,
445 fn defer_to_typeck(self) -> bool {
447 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
448 PathSource::Struct | PathSource::TupleStruct => true,
449 PathSource::Trait | PathSource::TraitItem(..) |
450 PathSource::Visibility | PathSource::ImportPrefix => false,
454 fn descr_expected(self) -> &'static str {
456 PathSource::Type => "type",
457 PathSource::Trait => "trait",
458 PathSource::Pat => "unit struct/variant or constant",
459 PathSource::Struct => "struct, variant or union type",
460 PathSource::TupleStruct => "tuple struct/variant",
461 PathSource::Visibility => "module",
462 PathSource::ImportPrefix => "module or enum",
463 PathSource::TraitItem(ns) => match ns {
464 TypeNS => "associated type",
465 ValueNS => "method or associated constant",
466 MacroNS => bug!("associated macro"),
468 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
469 // "function" here means "anything callable" rather than `Def::Fn`,
470 // this is not precise but usually more helpful than just "value".
471 Some(&ExprKind::Call(..)) => "function",
477 fn is_expected(self, def: Def) -> bool {
479 PathSource::Type => match def {
480 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
481 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
482 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
485 PathSource::Trait => match def {
486 Def::Trait(..) => true,
489 PathSource::Expr(..) => match def {
490 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
491 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
492 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
493 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
496 PathSource::Pat => match def {
497 Def::StructCtor(_, CtorKind::Const) |
498 Def::VariantCtor(_, CtorKind::Const) |
499 Def::Const(..) | Def::AssociatedConst(..) => true,
502 PathSource::TupleStruct => match def {
503 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
506 PathSource::Struct => match def {
507 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
508 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
511 PathSource::TraitItem(ns) => match def {
512 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
513 Def::AssociatedTy(..) if ns == TypeNS => true,
516 PathSource::ImportPrefix => match def {
517 Def::Mod(..) | Def::Enum(..) => true,
520 PathSource::Visibility => match def {
521 Def::Mod(..) => true,
527 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
528 __diagnostic_used!(E0404);
529 __diagnostic_used!(E0405);
530 __diagnostic_used!(E0412);
531 __diagnostic_used!(E0422);
532 __diagnostic_used!(E0423);
533 __diagnostic_used!(E0425);
534 __diagnostic_used!(E0531);
535 __diagnostic_used!(E0532);
536 __diagnostic_used!(E0573);
537 __diagnostic_used!(E0574);
538 __diagnostic_used!(E0575);
539 __diagnostic_used!(E0576);
540 __diagnostic_used!(E0577);
541 __diagnostic_used!(E0578);
542 match (self, has_unexpected_resolution) {
543 (PathSource::Trait, true) => "E0404",
544 (PathSource::Trait, false) => "E0405",
545 (PathSource::Type, true) => "E0573",
546 (PathSource::Type, false) => "E0412",
547 (PathSource::Struct, true) => "E0574",
548 (PathSource::Struct, false) => "E0422",
549 (PathSource::Expr(..), true) => "E0423",
550 (PathSource::Expr(..), false) => "E0425",
551 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
552 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
553 (PathSource::TraitItem(..), true) => "E0575",
554 (PathSource::TraitItem(..), false) => "E0576",
555 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
556 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
561 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
568 #[derive(Clone, Default, Debug)]
569 pub struct PerNS<T> {
575 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
577 fn index(&self, ns: Namespace) -> &T {
579 ValueNS => &self.value_ns,
580 TypeNS => &self.type_ns,
581 MacroNS => self.macro_ns.as_ref().unwrap(),
586 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
587 fn index_mut(&mut self, ns: Namespace) -> &mut T {
589 ValueNS => &mut self.value_ns,
590 TypeNS => &mut self.type_ns,
591 MacroNS => self.macro_ns.as_mut().unwrap(),
596 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
597 fn visit_item(&mut self, item: &'tcx Item) {
598 self.resolve_item(item);
600 fn visit_arm(&mut self, arm: &'tcx Arm) {
601 self.resolve_arm(arm);
603 fn visit_block(&mut self, block: &'tcx Block) {
604 self.resolve_block(block);
606 fn visit_expr(&mut self, expr: &'tcx Expr) {
607 self.resolve_expr(expr, None);
609 fn visit_local(&mut self, local: &'tcx Local) {
610 self.resolve_local(local);
612 fn visit_ty(&mut self, ty: &'tcx Ty) {
613 if let TyKind::Path(ref qself, ref path) = ty.node {
614 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
615 } else if let TyKind::ImplicitSelf = ty.node {
616 let self_ty = keywords::SelfType.ident();
617 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
618 .map_or(Def::Err, |d| d.def());
619 self.record_def(ty.id, PathResolution::new(def));
620 } else if let TyKind::Array(ref element, ref length) = ty.node {
621 self.visit_ty(element);
622 self.with_constant_rib(|this| {
623 this.visit_expr(length);
627 visit::walk_ty(self, ty);
629 fn visit_poly_trait_ref(&mut self,
630 tref: &'tcx ast::PolyTraitRef,
631 m: &'tcx ast::TraitBoundModifier) {
632 self.smart_resolve_path(tref.trait_ref.ref_id, None,
633 &tref.trait_ref.path, PathSource::Trait);
634 visit::walk_poly_trait_ref(self, tref, m);
636 fn visit_variant(&mut self,
637 variant: &'tcx ast::Variant,
638 generics: &'tcx Generics,
639 item_id: ast::NodeId) {
640 if let Some(ref dis_expr) = variant.node.disr_expr {
641 // resolve the discriminator expr as a constant
642 self.with_constant_rib(|this| {
643 this.visit_expr(dis_expr);
647 // `visit::walk_variant` without the discriminant expression.
648 self.visit_variant_data(&variant.node.data,
654 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
655 let type_parameters = match foreign_item.node {
656 ForeignItemKind::Fn(_, ref generics) => {
657 HasTypeParameters(generics, ItemRibKind)
659 ForeignItemKind::Static(..) => NoTypeParameters,
661 self.with_type_parameter_rib(type_parameters, |this| {
662 visit::walk_foreign_item(this, foreign_item);
665 fn visit_fn(&mut self,
666 function_kind: FnKind<'tcx>,
667 declaration: &'tcx FnDecl,
670 let rib_kind = match function_kind {
671 FnKind::ItemFn(_, generics, ..) => {
672 self.visit_generics(generics);
675 FnKind::Method(_, sig, _, _) => {
676 self.visit_generics(&sig.generics);
677 MethodRibKind(!sig.decl.has_self())
679 FnKind::Closure(_) => ClosureRibKind(node_id),
682 // Create a value rib for the function.
683 self.ribs[ValueNS].push(Rib::new(rib_kind));
685 // Create a label rib for the function.
686 self.label_ribs.push(Rib::new(rib_kind));
688 // Add each argument to the rib.
689 let mut bindings_list = FxHashMap();
690 for argument in &declaration.inputs {
691 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
693 self.visit_ty(&argument.ty);
695 debug!("(resolving function) recorded argument");
697 visit::walk_fn_ret_ty(self, &declaration.output);
699 // Resolve the function body.
700 match function_kind {
701 FnKind::ItemFn(.., body) |
702 FnKind::Method(.., body) => {
703 self.visit_block(body);
705 FnKind::Closure(body) => {
706 self.visit_expr(body);
710 debug!("(resolving function) leaving function");
712 self.label_ribs.pop();
713 self.ribs[ValueNS].pop();
715 fn visit_generics(&mut self, generics: &'tcx Generics) {
716 // For type parameter defaults, we have to ban access
717 // to following type parameters, as the Substs can only
718 // provide previous type parameters as they're built.
719 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
720 default_ban_rib.bindings.extend(generics.ty_params.iter()
721 .skip_while(|p| p.default.is_none())
722 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
724 for param in &generics.ty_params {
725 for bound in ¶m.bounds {
726 self.visit_ty_param_bound(bound);
729 if let Some(ref ty) = param.default {
730 self.ribs[TypeNS].push(default_ban_rib);
732 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
735 // Allow all following defaults to refer to this type parameter.
736 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
738 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
739 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
743 pub type ErrorMessage = Option<(Span, String)>;
745 #[derive(Copy, Clone)]
746 enum TypeParameters<'a, 'b> {
748 HasTypeParameters(// Type parameters.
751 // The kind of the rib used for type parameters.
755 // The rib kind controls the translation of local
756 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
757 #[derive(Copy, Clone, Debug)]
759 // No translation needs to be applied.
762 // We passed through a closure scope at the given node ID.
763 // Translate upvars as appropriate.
764 ClosureRibKind(NodeId /* func id */),
766 // We passed through an impl or trait and are now in one of its
767 // methods. Allow references to ty params that impl or trait
768 // binds. Disallow any other upvars (including other ty params that are
771 // The boolean value represents the fact that this method is static or not.
774 // We passed through an item scope. Disallow upvars.
777 // We're in a constant item. Can't refer to dynamic stuff.
780 // We passed through a module.
781 ModuleRibKind(Module<'a>),
783 // We passed through a `macro_rules!` statement
784 MacroDefinition(DefId),
786 // All bindings in this rib are type parameters that can't be used
787 // from the default of a type parameter because they're not declared
788 // before said type parameter. Also see the `visit_generics` override.
789 ForwardTyParamBanRibKind,
795 bindings: FxHashMap<Ident, Def>,
800 fn new(kind: RibKind<'a>) -> Rib<'a> {
802 bindings: FxHashMap(),
808 enum LexicalScopeBinding<'a> {
809 Item(&'a NameBinding<'a>),
813 impl<'a> LexicalScopeBinding<'a> {
814 fn item(self) -> Option<&'a NameBinding<'a>> {
816 LexicalScopeBinding::Item(binding) => Some(binding),
821 fn def(self) -> Def {
823 LexicalScopeBinding::Item(binding) => binding.def(),
824 LexicalScopeBinding::Def(def) => def,
830 enum PathResult<'a> {
832 NonModule(PathResolution),
834 Failed(String, bool /* is the error from the last segment? */),
842 /// One node in the tree of modules.
843 pub struct ModuleData<'a> {
844 parent: Option<Module<'a>>,
847 // The def id of the closest normal module (`mod`) ancestor (including this module).
848 normal_ancestor_id: DefId,
850 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
851 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
852 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
854 // Macro invocations that can expand into items in this module.
855 unresolved_invocations: RefCell<FxHashSet<Mark>>,
857 no_implicit_prelude: bool,
859 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
860 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
862 // Used to memoize the traits in this module for faster searches through all traits in scope.
863 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
865 // Whether this module is populated. If not populated, any attempt to
866 // access the children must be preceded with a
867 // `populate_module_if_necessary` call.
868 populated: Cell<bool>,
870 /// Span of the module itself. Used for error reporting.
874 pub type Module<'a> = &'a ModuleData<'a>;
876 impl<'a> ModuleData<'a> {
877 fn new(parent: Option<Module<'a>>,
879 normal_ancestor_id: DefId,
880 span: Span) -> Self {
884 normal_ancestor_id: normal_ancestor_id,
885 resolutions: RefCell::new(FxHashMap()),
886 legacy_macro_resolutions: RefCell::new(Vec::new()),
887 macro_resolutions: RefCell::new(Vec::new()),
888 unresolved_invocations: RefCell::new(FxHashSet()),
889 no_implicit_prelude: false,
890 glob_importers: RefCell::new(Vec::new()),
891 globs: RefCell::new((Vec::new())),
892 traits: RefCell::new(None),
893 populated: Cell::new(normal_ancestor_id.is_local()),
898 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
899 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
900 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
904 fn def(&self) -> Option<Def> {
906 ModuleKind::Def(def, _) => Some(def),
911 fn def_id(&self) -> Option<DefId> {
912 self.def().as_ref().map(Def::def_id)
915 // `self` resolves to the first module ancestor that `is_normal`.
916 fn is_normal(&self) -> bool {
918 ModuleKind::Def(Def::Mod(_), _) => true,
923 fn is_trait(&self) -> bool {
925 ModuleKind::Def(Def::Trait(_), _) => true,
930 fn is_local(&self) -> bool {
931 self.normal_ancestor_id.is_local()
934 fn nearest_item_scope(&'a self) -> Module<'a> {
935 if self.is_trait() { self.parent.unwrap() } else { self }
939 impl<'a> fmt::Debug for ModuleData<'a> {
940 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
941 write!(f, "{:?}", self.def())
945 // Records a possibly-private value, type, or module definition.
946 #[derive(Clone, Debug)]
947 pub struct NameBinding<'a> {
948 kind: NameBindingKind<'a>,
954 pub trait ToNameBinding<'a> {
955 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
958 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
959 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
964 #[derive(Clone, Debug)]
965 enum NameBindingKind<'a> {
969 binding: &'a NameBinding<'a>,
970 directive: &'a ImportDirective<'a>,
972 legacy_self_import: bool,
975 b1: &'a NameBinding<'a>,
976 b2: &'a NameBinding<'a>,
981 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
983 struct AmbiguityError<'a> {
987 b1: &'a NameBinding<'a>,
988 b2: &'a NameBinding<'a>,
992 impl<'a> NameBinding<'a> {
993 fn module(&self) -> Option<Module<'a>> {
995 NameBindingKind::Module(module) => Some(module),
996 NameBindingKind::Import { binding, .. } => binding.module(),
997 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1002 fn def(&self) -> Def {
1004 NameBindingKind::Def(def) => def,
1005 NameBindingKind::Module(module) => module.def().unwrap(),
1006 NameBindingKind::Import { binding, .. } => binding.def(),
1007 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1008 NameBindingKind::Ambiguity { .. } => Def::Err,
1012 fn def_ignoring_ambiguity(&self) -> Def {
1014 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1015 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1020 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
1021 resolver.get_macro(self.def_ignoring_ambiguity())
1024 // We sometimes need to treat variants as `pub` for backwards compatibility
1025 fn pseudo_vis(&self) -> ty::Visibility {
1026 if self.is_variant() { ty::Visibility::Public } else { self.vis }
1029 fn is_variant(&self) -> bool {
1031 NameBindingKind::Def(Def::Variant(..)) |
1032 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1037 fn is_extern_crate(&self) -> bool {
1039 NameBindingKind::Import {
1040 directive: &ImportDirective {
1041 subclass: ImportDirectiveSubclass::ExternCrate, ..
1048 fn is_import(&self) -> bool {
1050 NameBindingKind::Import { .. } => true,
1055 fn is_glob_import(&self) -> bool {
1057 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1058 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1063 fn is_importable(&self) -> bool {
1065 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1071 /// Interns the names of the primitive types.
1072 struct PrimitiveTypeTable {
1073 primitive_types: FxHashMap<Name, PrimTy>,
1076 impl PrimitiveTypeTable {
1077 fn new() -> PrimitiveTypeTable {
1078 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1080 table.intern("bool", TyBool);
1081 table.intern("char", TyChar);
1082 table.intern("f32", TyFloat(FloatTy::F32));
1083 table.intern("f64", TyFloat(FloatTy::F64));
1084 table.intern("isize", TyInt(IntTy::Is));
1085 table.intern("i8", TyInt(IntTy::I8));
1086 table.intern("i16", TyInt(IntTy::I16));
1087 table.intern("i32", TyInt(IntTy::I32));
1088 table.intern("i64", TyInt(IntTy::I64));
1089 table.intern("i128", TyInt(IntTy::I128));
1090 table.intern("str", TyStr);
1091 table.intern("usize", TyUint(UintTy::Us));
1092 table.intern("u8", TyUint(UintTy::U8));
1093 table.intern("u16", TyUint(UintTy::U16));
1094 table.intern("u32", TyUint(UintTy::U32));
1095 table.intern("u64", TyUint(UintTy::U64));
1096 table.intern("u128", TyUint(UintTy::U128));
1100 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1101 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1105 /// The main resolver class.
1106 pub struct Resolver<'a> {
1107 session: &'a Session,
1109 pub definitions: Definitions,
1111 graph_root: Module<'a>,
1113 prelude: Option<Module<'a>>,
1115 trait_item_map: FxHashMap<(DefId, Name, Namespace), (Def, bool /* has self */)>,
1117 // Names of fields of an item `DefId` accessible with dot syntax.
1118 // Used for hints during error reporting.
1119 field_names: FxHashMap<DefId, Vec<Name>>,
1121 // All imports known to succeed or fail.
1122 determined_imports: Vec<&'a ImportDirective<'a>>,
1124 // All non-determined imports.
1125 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1127 // The module that represents the current item scope.
1128 current_module: Module<'a>,
1130 // The current set of local scopes for types and values.
1131 // FIXME #4948: Reuse ribs to avoid allocation.
1132 ribs: PerNS<Vec<Rib<'a>>>,
1134 // The current set of local scopes, for labels.
1135 label_ribs: Vec<Rib<'a>>,
1137 // The trait that the current context can refer to.
1138 current_trait_ref: Option<(DefId, TraitRef)>,
1140 // The current self type if inside an impl (used for better errors).
1141 current_self_type: Option<Ty>,
1143 // The idents for the primitive types.
1144 primitive_type_table: PrimitiveTypeTable,
1147 pub freevars: FreevarMap,
1148 freevars_seen: NodeMap<NodeMap<usize>>,
1149 pub export_map: ExportMap,
1150 pub trait_map: TraitMap,
1152 // A map from nodes to anonymous modules.
1153 // Anonymous modules are pseudo-modules that are implicitly created around items
1154 // contained within blocks.
1156 // For example, if we have this:
1164 // There will be an anonymous module created around `g` with the ID of the
1165 // entry block for `f`.
1166 block_map: NodeMap<Module<'a>>,
1167 module_map: FxHashMap<DefId, Module<'a>>,
1168 extern_crate_roots: FxHashMap<(CrateNum, bool /* MacrosOnly? */), Module<'a>>,
1170 pub make_glob_map: bool,
1171 // Maps imports to the names of items actually imported (this actually maps
1172 // all imports, but only glob imports are actually interesting).
1173 pub glob_map: GlobMap,
1175 used_imports: FxHashSet<(NodeId, Namespace)>,
1176 pub maybe_unused_trait_imports: NodeSet,
1178 privacy_errors: Vec<PrivacyError<'a>>,
1179 ambiguity_errors: Vec<AmbiguityError<'a>>,
1180 gated_errors: FxHashSet<Span>,
1181 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1183 arenas: &'a ResolverArenas<'a>,
1184 dummy_binding: &'a NameBinding<'a>,
1185 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1187 crate_loader: &'a mut CrateLoader,
1188 macro_names: FxHashSet<Name>,
1189 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1190 lexical_macro_resolutions: Vec<(Name, &'a Cell<LegacyScope<'a>>)>,
1191 macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
1192 macro_defs: FxHashMap<Mark, DefId>,
1193 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1194 macro_exports: Vec<Export>,
1195 pub whitelisted_legacy_custom_derives: Vec<Name>,
1196 pub found_unresolved_macro: bool,
1198 // Maps the `Mark` of an expansion to its containing module or block.
1199 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1201 // Avoid duplicated errors for "name already defined".
1202 name_already_seen: FxHashMap<Name, Span>,
1204 // If `#![feature(proc_macro)]` is set
1205 proc_macro_enabled: bool,
1207 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1208 warned_proc_macros: FxHashSet<Name>,
1210 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1212 // This table maps struct IDs into struct constructor IDs,
1213 // it's not used during normal resolution, only for better error reporting.
1214 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1217 pub struct ResolverArenas<'a> {
1218 modules: arena::TypedArena<ModuleData<'a>>,
1219 local_modules: RefCell<Vec<Module<'a>>>,
1220 name_bindings: arena::TypedArena<NameBinding<'a>>,
1221 import_directives: arena::TypedArena<ImportDirective<'a>>,
1222 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1223 invocation_data: arena::TypedArena<InvocationData<'a>>,
1224 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1227 impl<'a> ResolverArenas<'a> {
1228 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1229 let module = self.modules.alloc(module);
1230 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1231 self.local_modules.borrow_mut().push(module);
1235 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1236 self.local_modules.borrow()
1238 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1239 self.name_bindings.alloc(name_binding)
1241 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1242 -> &'a ImportDirective {
1243 self.import_directives.alloc(import_directive)
1245 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1246 self.name_resolutions.alloc(Default::default())
1248 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1249 -> &'a InvocationData<'a> {
1250 self.invocation_data.alloc(expansion_data)
1252 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1253 self.legacy_bindings.alloc(binding)
1257 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1258 fn parent(self, id: DefId) -> Option<DefId> {
1260 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1261 _ => self.session.cstore.def_key(id).parent,
1262 }.map(|index| DefId { index: index, ..id })
1266 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1267 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1268 let namespace = if is_value { ValueNS } else { TypeNS };
1269 let hir::Path { ref segments, span, ref mut def } = *path;
1270 let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect();
1271 match self.resolve_path(&path, Some(namespace), true, span) {
1272 PathResult::Module(module) => *def = module.def().unwrap(),
1273 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1274 *def = path_res.base_def(),
1275 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1276 PathResult::Failed(msg, _) => {
1277 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1281 PathResult::Indeterminate => unreachable!(),
1282 PathResult::Failed(msg, _) => {
1283 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1288 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1289 self.def_map.get(&id).cloned()
1292 fn definitions(&mut self) -> &mut Definitions {
1293 &mut self.definitions
1297 impl<'a> Resolver<'a> {
1298 pub fn new(session: &'a Session,
1301 make_glob_map: MakeGlobMap,
1302 crate_loader: &'a mut CrateLoader,
1303 arenas: &'a ResolverArenas<'a>)
1305 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1306 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1307 let graph_root = arenas.alloc_module(ModuleData {
1308 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1309 ..ModuleData::new(None, root_module_kind, root_def_id, krate.span)
1311 let mut module_map = FxHashMap();
1312 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1314 let mut definitions = Definitions::new();
1315 DefCollector::new(&mut definitions)
1316 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1318 let mut invocations = FxHashMap();
1319 invocations.insert(Mark::root(),
1320 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1322 let features = session.features.borrow();
1324 let mut macro_defs = FxHashMap();
1325 macro_defs.insert(Mark::root(), root_def_id);
1330 definitions: definitions,
1332 // The outermost module has def ID 0; this is not reflected in the
1334 graph_root: graph_root,
1337 trait_item_map: FxHashMap(),
1338 field_names: FxHashMap(),
1340 determined_imports: Vec::new(),
1341 indeterminate_imports: Vec::new(),
1343 current_module: graph_root,
1345 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1346 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1347 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1349 label_ribs: Vec::new(),
1351 current_trait_ref: None,
1352 current_self_type: None,
1354 primitive_type_table: PrimitiveTypeTable::new(),
1357 freevars: NodeMap(),
1358 freevars_seen: NodeMap(),
1359 export_map: NodeMap(),
1360 trait_map: NodeMap(),
1361 module_map: module_map,
1362 block_map: NodeMap(),
1363 extern_crate_roots: FxHashMap(),
1365 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1366 glob_map: NodeMap(),
1368 used_imports: FxHashSet(),
1369 maybe_unused_trait_imports: NodeSet(),
1371 privacy_errors: Vec::new(),
1372 ambiguity_errors: Vec::new(),
1373 gated_errors: FxHashSet(),
1374 disallowed_shadowing: Vec::new(),
1377 dummy_binding: arenas.alloc_name_binding(NameBinding {
1378 kind: NameBindingKind::Def(Def::Err),
1379 expansion: Mark::root(),
1381 vis: ty::Visibility::Public,
1384 // `#![feature(proc_macro)]` implies `#[feature(extern_macros)]`
1385 use_extern_macros: features.use_extern_macros || features.proc_macro,
1387 crate_loader: crate_loader,
1388 macro_names: FxHashSet(),
1389 global_macros: FxHashMap(),
1390 lexical_macro_resolutions: Vec::new(),
1391 macro_map: FxHashMap(),
1392 macro_exports: Vec::new(),
1393 invocations: invocations,
1394 macro_defs: macro_defs,
1395 local_macro_def_scopes: FxHashMap(),
1396 name_already_seen: FxHashMap(),
1397 whitelisted_legacy_custom_derives: Vec::new(),
1398 proc_macro_enabled: features.proc_macro,
1399 warned_proc_macros: FxHashSet(),
1400 potentially_unused_imports: Vec::new(),
1401 struct_constructors: DefIdMap(),
1402 found_unresolved_macro: false,
1406 pub fn arenas() -> ResolverArenas<'a> {
1408 modules: arena::TypedArena::new(),
1409 local_modules: RefCell::new(Vec::new()),
1410 name_bindings: arena::TypedArena::new(),
1411 import_directives: arena::TypedArena::new(),
1412 name_resolutions: arena::TypedArena::new(),
1413 invocation_data: arena::TypedArena::new(),
1414 legacy_bindings: arena::TypedArena::new(),
1418 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1420 type_ns: f(self, TypeNS),
1421 value_ns: f(self, ValueNS),
1422 macro_ns: match self.use_extern_macros {
1423 true => Some(f(self, MacroNS)),
1429 /// Entry point to crate resolution.
1430 pub fn resolve_crate(&mut self, krate: &Crate) {
1431 ImportResolver { resolver: self }.finalize_imports();
1432 self.current_module = self.graph_root;
1433 self.finalize_current_module_macro_resolutions();
1434 visit::walk_crate(self, krate);
1436 check_unused::check_crate(self, krate);
1437 self.report_errors();
1438 self.crate_loader.postprocess(krate);
1445 normal_ancestor_id: DefId,
1448 self.arenas.alloc_module(ModuleData::new(Some(parent), kind, normal_ancestor_id, span))
1451 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1452 -> bool /* true if an error was reported */ {
1453 match binding.kind {
1454 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1457 directive.used.set(true);
1458 if legacy_self_import {
1459 self.warn_legacy_self_import(directive);
1462 self.used_imports.insert((directive.id, ns));
1463 self.add_to_glob_map(directive.id, ident);
1464 self.record_use(ident, ns, binding, span)
1466 NameBindingKind::Import { .. } => false,
1467 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1468 self.ambiguity_errors.push(AmbiguityError {
1469 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
1472 self.record_use(ident, ns, b1, span);
1480 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1481 if self.make_glob_map {
1482 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1486 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1487 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1488 /// `ident` in the first scope that defines it (or None if no scopes define it).
1490 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1491 /// the items are defined in the block. For example,
1494 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1497 /// g(); // This resolves to the local variable `g` since it shadows the item.
1501 /// Invariant: This must only be called during main resolution, not during
1502 /// import resolution.
1503 fn resolve_ident_in_lexical_scope(&mut self,
1508 -> Option<LexicalScopeBinding<'a>> {
1510 ident = ident.unhygienize();
1513 // Walk backwards up the ribs in scope.
1514 for i in (0 .. self.ribs[ns].len()).rev() {
1515 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1516 // The ident resolves to a type parameter or local variable.
1517 return Some(LexicalScopeBinding::Def(
1518 self.adjust_local_def(ns, i, def, record_used, path_span)
1522 if let ModuleRibKind(module) = self.ribs[ns][i].kind {
1523 let item = self.resolve_ident_in_module(module, ident, ns, false,
1524 record_used, path_span);
1525 if let Ok(binding) = item {
1526 // The ident resolves to an item.
1527 return Some(LexicalScopeBinding::Item(binding));
1530 if let ModuleKind::Block(..) = module.kind { // We can see through blocks
1531 } else if !module.no_implicit_prelude {
1532 return self.prelude.and_then(|prelude| {
1533 self.resolve_ident_in_module(prelude, ident, ns, false,
1534 false, path_span).ok()
1535 }).map(LexicalScopeBinding::Item)
1541 if let MacroDefinition(def) = self.ribs[ns][i].kind {
1542 // If an invocation of this macro created `ident`, give up on `ident`
1543 // and switch to `ident`'s source from the macro definition.
1544 let ctxt_data = ident.ctxt.data();
1545 if def == self.macro_defs[&ctxt_data.outer_mark] {
1546 ident.ctxt = ctxt_data.prev_ctxt;
1554 fn resolve_crate_var(&mut self, crate_var_ctxt: SyntaxContext, span: Span) -> Module<'a> {
1555 let mut ctxt_data = crate_var_ctxt.data();
1556 while ctxt_data.prev_ctxt != SyntaxContext::empty() {
1557 ctxt_data = ctxt_data.prev_ctxt.data();
1559 let module = self.macro_def_scope(ctxt_data.outer_mark, span);
1560 if module.is_local() { self.graph_root } else { module }
1565 // We maintain a list of value ribs and type ribs.
1567 // Simultaneously, we keep track of the current position in the module
1568 // graph in the `current_module` pointer. When we go to resolve a name in
1569 // the value or type namespaces, we first look through all the ribs and
1570 // then query the module graph. When we resolve a name in the module
1571 // namespace, we can skip all the ribs (since nested modules are not
1572 // allowed within blocks in Rust) and jump straight to the current module
1575 // Named implementations are handled separately. When we find a method
1576 // call, we consult the module node to find all of the implementations in
1577 // scope. This information is lazily cached in the module node. We then
1578 // generate a fake "implementation scope" containing all the
1579 // implementations thus found, for compatibility with old resolve pass.
1581 fn with_scope<F>(&mut self, id: NodeId, f: F)
1582 where F: FnOnce(&mut Resolver)
1584 let id = self.definitions.local_def_id(id);
1585 let module = self.module_map.get(&id).cloned(); // clones a reference
1586 if let Some(module) = module {
1587 // Move down in the graph.
1588 let orig_module = replace(&mut self.current_module, module);
1589 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1590 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1592 self.finalize_current_module_macro_resolutions();
1595 self.current_module = orig_module;
1596 self.ribs[ValueNS].pop();
1597 self.ribs[TypeNS].pop();
1603 /// Searches the current set of local scopes for labels.
1604 /// Stops after meeting a closure.
1605 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1606 for rib in self.label_ribs.iter().rev() {
1611 MacroDefinition(def) => {
1612 // If an invocation of this macro created `ident`, give up on `ident`
1613 // and switch to `ident`'s source from the macro definition.
1614 let ctxt_data = ident.ctxt.data();
1615 if def == self.macro_defs[&ctxt_data.outer_mark] {
1616 ident.ctxt = ctxt_data.prev_ctxt;
1620 // Do not resolve labels across function boundary
1624 let result = rib.bindings.get(&ident).cloned();
1625 if result.is_some() {
1632 fn resolve_item(&mut self, item: &Item) {
1633 let name = item.ident.name;
1635 debug!("(resolving item) resolving {}", name);
1637 self.check_proc_macro_attrs(&item.attrs);
1640 ItemKind::Enum(_, ref generics) |
1641 ItemKind::Ty(_, ref generics) |
1642 ItemKind::Struct(_, ref generics) |
1643 ItemKind::Union(_, ref generics) |
1644 ItemKind::Fn(.., ref generics, _) => {
1645 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1646 |this| visit::walk_item(this, item));
1649 ItemKind::DefaultImpl(_, ref trait_ref) => {
1650 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1651 // Resolve type arguments in trait path
1652 visit::walk_trait_ref(this, trait_ref);
1655 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1656 self.resolve_implementation(generics,
1662 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1663 // Create a new rib for the trait-wide type parameters.
1664 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1665 let local_def_id = this.definitions.local_def_id(item.id);
1666 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1667 this.visit_generics(generics);
1668 walk_list!(this, visit_ty_param_bound, bounds);
1670 for trait_item in trait_items {
1671 this.check_proc_macro_attrs(&trait_item.attrs);
1673 match trait_item.node {
1674 TraitItemKind::Const(_, ref default) => {
1675 // Only impose the restrictions of
1676 // ConstRibKind if there's an actual constant
1677 // expression in a provided default.
1678 if default.is_some() {
1679 this.with_constant_rib(|this| {
1680 visit::walk_trait_item(this, trait_item)
1683 visit::walk_trait_item(this, trait_item)
1686 TraitItemKind::Method(ref sig, _) => {
1687 let type_parameters =
1688 HasTypeParameters(&sig.generics,
1689 MethodRibKind(!sig.decl.has_self()));
1690 this.with_type_parameter_rib(type_parameters, |this| {
1691 visit::walk_trait_item(this, trait_item)
1694 TraitItemKind::Type(..) => {
1695 this.with_type_parameter_rib(NoTypeParameters, |this| {
1696 visit::walk_trait_item(this, trait_item)
1699 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1706 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1707 self.with_scope(item.id, |this| {
1708 visit::walk_item(this, item);
1712 ItemKind::Const(..) | ItemKind::Static(..) => {
1713 self.with_constant_rib(|this| {
1714 visit::walk_item(this, item);
1718 ItemKind::Use(ref view_path) => {
1719 match view_path.node {
1720 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1721 // Resolve prefix of an import with empty braces (issue #28388).
1722 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1728 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1729 // do nothing, these are just around to be encoded
1732 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1736 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1737 where F: FnOnce(&mut Resolver)
1739 match type_parameters {
1740 HasTypeParameters(generics, rib_kind) => {
1741 let mut function_type_rib = Rib::new(rib_kind);
1742 let mut seen_bindings = FxHashMap();
1743 for type_parameter in &generics.ty_params {
1744 let name = type_parameter.ident.name;
1745 debug!("with_type_parameter_rib: {}", type_parameter.id);
1747 if seen_bindings.contains_key(&name) {
1748 let span = seen_bindings.get(&name).unwrap();
1750 type_parameter.span,
1751 ResolutionError::NameAlreadyUsedInTypeParameterList(name,
1754 seen_bindings.entry(name).or_insert(type_parameter.span);
1756 // plain insert (no renaming)
1757 let def_id = self.definitions.local_def_id(type_parameter.id);
1758 let def = Def::TyParam(def_id);
1759 function_type_rib.bindings.insert(Ident::with_empty_ctxt(name), def);
1760 self.record_def(type_parameter.id, PathResolution::new(def));
1762 self.ribs[TypeNS].push(function_type_rib);
1765 NoTypeParameters => {
1772 if let HasTypeParameters(..) = type_parameters {
1773 self.ribs[TypeNS].pop();
1777 fn with_label_rib<F>(&mut self, f: F)
1778 where F: FnOnce(&mut Resolver)
1780 self.label_ribs.push(Rib::new(NormalRibKind));
1782 self.label_ribs.pop();
1785 fn with_constant_rib<F>(&mut self, f: F)
1786 where F: FnOnce(&mut Resolver)
1788 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1789 self.ribs[TypeNS].push(Rib::new(ConstantItemRibKind));
1791 self.ribs[TypeNS].pop();
1792 self.ribs[ValueNS].pop();
1795 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1796 where F: FnOnce(&mut Resolver) -> T
1798 // Handle nested impls (inside fn bodies)
1799 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1800 let result = f(self);
1801 self.current_self_type = previous_value;
1805 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1806 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1808 let mut new_val = None;
1809 let mut new_id = None;
1810 if let Some(trait_ref) = opt_trait_ref {
1811 let def = self.smart_resolve_path(trait_ref.ref_id, None,
1812 &trait_ref.path, PathSource::Trait).base_def();
1813 if def != Def::Err {
1814 new_val = Some((def.def_id(), trait_ref.clone()));
1815 new_id = Some(def.def_id());
1818 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1819 let result = f(self, new_id);
1820 self.current_trait_ref = original_trait_ref;
1824 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1825 where F: FnOnce(&mut Resolver)
1827 let mut self_type_rib = Rib::new(NormalRibKind);
1829 // plain insert (no renaming, types are not currently hygienic....)
1830 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
1831 self.ribs[TypeNS].push(self_type_rib);
1833 self.ribs[TypeNS].pop();
1836 fn resolve_implementation(&mut self,
1837 generics: &Generics,
1838 opt_trait_reference: &Option<TraitRef>,
1841 impl_items: &[ImplItem]) {
1842 // If applicable, create a rib for the type parameters.
1843 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1844 // Dummy self type for better errors if `Self` is used in the trait path.
1845 this.with_self_rib(Def::SelfTy(None, None), |this| {
1846 // Resolve the trait reference, if necessary.
1847 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1848 let item_def_id = this.definitions.local_def_id(item_id);
1849 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
1850 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1851 // Resolve type arguments in trait path
1852 visit::walk_trait_ref(this, trait_ref);
1854 // Resolve the self type.
1855 this.visit_ty(self_type);
1856 // Resolve the type parameters.
1857 this.visit_generics(generics);
1858 this.with_current_self_type(self_type, |this| {
1859 for impl_item in impl_items {
1860 this.check_proc_macro_attrs(&impl_item.attrs);
1861 this.resolve_visibility(&impl_item.vis);
1862 match impl_item.node {
1863 ImplItemKind::Const(..) => {
1864 // If this is a trait impl, ensure the const
1866 this.check_trait_item(impl_item.ident.name,
1869 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
1870 visit::walk_impl_item(this, impl_item);
1872 ImplItemKind::Method(ref sig, _) => {
1873 // If this is a trait impl, ensure the method
1875 this.check_trait_item(impl_item.ident.name,
1878 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
1880 // We also need a new scope for the method-
1881 // specific type parameters.
1882 let type_parameters =
1883 HasTypeParameters(&sig.generics,
1884 MethodRibKind(!sig.decl.has_self()));
1885 this.with_type_parameter_rib(type_parameters, |this| {
1886 visit::walk_impl_item(this, impl_item);
1889 ImplItemKind::Type(ref ty) => {
1890 // If this is a trait impl, ensure the type
1892 this.check_trait_item(impl_item.ident.name,
1895 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
1899 ImplItemKind::Macro(_) =>
1900 panic!("unexpanded macro in resolve!"),
1910 fn check_trait_item<F>(&self, name: Name, ns: Namespace, span: Span, err: F)
1911 where F: FnOnce(Name, &str) -> ResolutionError
1913 // If there is a TraitRef in scope for an impl, then the method must be in the
1915 if let Some((did, ref trait_ref)) = self.current_trait_ref {
1916 if !self.trait_item_map.contains_key(&(did, name, ns)) {
1917 let path_str = path_names_to_string(&trait_ref.path);
1918 resolve_error(self, span, err(name, &path_str));
1923 fn resolve_local(&mut self, local: &Local) {
1924 // Resolve the type.
1925 walk_list!(self, visit_ty, &local.ty);
1927 // Resolve the initializer.
1928 walk_list!(self, visit_expr, &local.init);
1930 // Resolve the pattern.
1931 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
1934 // build a map from pattern identifiers to binding-info's.
1935 // this is done hygienically. This could arise for a macro
1936 // that expands into an or-pattern where one 'x' was from the
1937 // user and one 'x' came from the macro.
1938 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
1939 let mut binding_map = FxHashMap();
1941 pat.walk(&mut |pat| {
1942 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
1943 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
1944 Some(Def::Local(..)) => true,
1947 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
1948 binding_map.insert(ident.node, binding_info);
1957 // check that all of the arms in an or-pattern have exactly the
1958 // same set of bindings, with the same binding modes for each.
1959 fn check_consistent_bindings(&mut self, arm: &Arm) {
1960 if arm.pats.is_empty() {
1964 let mut missing_vars = FxHashMap();
1965 let mut inconsistent_vars = FxHashMap();
1966 for (i, p) in arm.pats.iter().enumerate() {
1967 let map_i = self.binding_mode_map(&p);
1969 for (j, q) in arm.pats.iter().enumerate() {
1974 let map_j = self.binding_mode_map(&q);
1975 for (&key, &binding_i) in &map_i {
1976 if map_j.len() == 0 { // Account for missing bindings when
1977 let binding_error = missing_vars // map_j has none.
1979 .or_insert(BindingError {
1981 origin: BTreeSet::new(),
1982 target: BTreeSet::new(),
1984 binding_error.origin.insert(binding_i.span);
1985 binding_error.target.insert(q.span);
1987 for (&key_j, &binding_j) in &map_j {
1988 match map_i.get(&key_j) {
1989 None => { // missing binding
1990 let binding_error = missing_vars
1992 .or_insert(BindingError {
1994 origin: BTreeSet::new(),
1995 target: BTreeSet::new(),
1997 binding_error.origin.insert(binding_j.span);
1998 binding_error.target.insert(p.span);
2000 Some(binding_i) => { // check consistent binding
2001 if binding_i.binding_mode != binding_j.binding_mode {
2004 .or_insert((binding_j.span, binding_i.span));
2012 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2013 missing_vars.sort();
2014 for (_, v) in missing_vars {
2016 *v.origin.iter().next().unwrap(),
2017 ResolutionError::VariableNotBoundInPattern(v));
2019 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2020 inconsistent_vars.sort();
2021 for (name, v) in inconsistent_vars {
2022 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2026 fn resolve_arm(&mut self, arm: &Arm) {
2027 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2029 let mut bindings_list = FxHashMap();
2030 for pattern in &arm.pats {
2031 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2034 // This has to happen *after* we determine which
2035 // pat_idents are variants
2036 self.check_consistent_bindings(arm);
2038 walk_list!(self, visit_expr, &arm.guard);
2039 self.visit_expr(&arm.body);
2041 self.ribs[ValueNS].pop();
2044 fn resolve_block(&mut self, block: &Block) {
2045 debug!("(resolving block) entering block");
2046 // Move down in the graph, if there's an anonymous module rooted here.
2047 let orig_module = self.current_module;
2048 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2050 let mut num_macro_definition_ribs = 0;
2051 if let Some(anonymous_module) = anonymous_module {
2052 debug!("(resolving block) found anonymous module, moving down");
2053 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2054 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2055 self.current_module = anonymous_module;
2056 self.finalize_current_module_macro_resolutions();
2058 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2061 // Descend into the block.
2062 for stmt in &block.stmts {
2063 if let ast::StmtKind::Item(ref item) = stmt.node {
2064 if let ast::ItemKind::MacroDef(..) = item.node {
2065 num_macro_definition_ribs += 1;
2066 let def = self.definitions.local_def_id(item.id);
2067 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2068 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2072 self.visit_stmt(stmt);
2076 self.current_module = orig_module;
2077 for _ in 0 .. num_macro_definition_ribs {
2078 self.ribs[ValueNS].pop();
2079 self.label_ribs.pop();
2081 self.ribs[ValueNS].pop();
2082 if let Some(_) = anonymous_module {
2083 self.ribs[TypeNS].pop();
2085 debug!("(resolving block) leaving block");
2088 fn fresh_binding(&mut self,
2089 ident: &SpannedIdent,
2091 outer_pat_id: NodeId,
2092 pat_src: PatternSource,
2093 bindings: &mut FxHashMap<Ident, NodeId>)
2095 // Add the binding to the local ribs, if it
2096 // doesn't already exist in the bindings map. (We
2097 // must not add it if it's in the bindings map
2098 // because that breaks the assumptions later
2099 // passes make about or-patterns.)
2100 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2101 match bindings.get(&ident.node).cloned() {
2102 Some(id) if id == outer_pat_id => {
2103 // `Variant(a, a)`, error
2107 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2108 &ident.node.name.as_str())
2111 Some(..) if pat_src == PatternSource::FnParam => {
2112 // `fn f(a: u8, a: u8)`, error
2116 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2117 &ident.node.name.as_str())
2120 Some(..) if pat_src == PatternSource::Match => {
2121 // `Variant1(a) | Variant2(a)`, ok
2122 // Reuse definition from the first `a`.
2123 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2126 span_bug!(ident.span, "two bindings with the same name from \
2127 unexpected pattern source {:?}", pat_src);
2130 // A completely fresh binding, add to the lists if it's valid.
2131 if ident.node.name != keywords::Invalid.name() {
2132 bindings.insert(ident.node, outer_pat_id);
2133 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2138 PathResolution::new(def)
2141 fn resolve_pattern(&mut self,
2143 pat_src: PatternSource,
2144 // Maps idents to the node ID for the
2145 // outermost pattern that binds them.
2146 bindings: &mut FxHashMap<Ident, NodeId>) {
2147 // Visit all direct subpatterns of this pattern.
2148 let outer_pat_id = pat.id;
2149 pat.walk(&mut |pat| {
2151 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2152 // First try to resolve the identifier as some existing
2153 // entity, then fall back to a fresh binding.
2154 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2156 .and_then(LexicalScopeBinding::item);
2157 let resolution = binding.map(NameBinding::def).and_then(|def| {
2158 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2159 bmode != BindingMode::ByValue(Mutability::Immutable);
2161 Def::StructCtor(_, CtorKind::Const) |
2162 Def::VariantCtor(_, CtorKind::Const) |
2163 Def::Const(..) if !always_binding => {
2164 // A unit struct/variant or constant pattern.
2165 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2166 Some(PathResolution::new(def))
2168 Def::StructCtor(..) | Def::VariantCtor(..) |
2169 Def::Const(..) | Def::Static(..) => {
2170 // A fresh binding that shadows something unacceptable.
2174 ResolutionError::BindingShadowsSomethingUnacceptable(
2175 pat_src.descr(), ident.node.name, binding.unwrap())
2179 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2180 // These entities are explicitly allowed
2181 // to be shadowed by fresh bindings.
2185 span_bug!(ident.span, "unexpected definition for an \
2186 identifier in pattern: {:?}", def);
2189 }).unwrap_or_else(|| {
2190 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2193 self.record_def(pat.id, resolution);
2196 PatKind::TupleStruct(ref path, ..) => {
2197 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2200 PatKind::Path(ref qself, ref path) => {
2201 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2204 PatKind::Struct(ref path, ..) => {
2205 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2213 visit::walk_pat(self, pat);
2216 // High-level and context dependent path resolution routine.
2217 // Resolves the path and records the resolution into definition map.
2218 // If resolution fails tries several techniques to find likely
2219 // resolution candidates, suggest imports or other help, and report
2220 // errors in user friendly way.
2221 fn smart_resolve_path(&mut self,
2223 qself: Option<&QSelf>,
2227 let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
2228 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2229 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2232 fn smart_resolve_path_fragment(&mut self,
2234 qself: Option<&QSelf>,
2240 let ns = source.namespace();
2241 let is_expected = &|def| source.is_expected(def);
2242 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2244 // Base error is amended with one short label and possibly some longer helps/notes.
2245 let report_errors = |this: &mut Self, def: Option<Def>| {
2246 // Make the base error.
2247 let expected = source.descr_expected();
2248 let path_str = names_to_string(path);
2249 let code = source.error_code(def.is_some());
2250 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2251 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2252 format!("not a {}", expected), span)
2254 let item_str = path[path.len() - 1];
2255 let (mod_prefix, mod_str) = if path.len() == 1 {
2256 (format!(""), format!("this scope"))
2257 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2258 (format!(""), format!("the crate root"))
2260 let mod_path = &path[..path.len() - 1];
2261 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2262 PathResult::Module(module) => module.def(),
2264 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2265 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2267 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2268 format!("not found in {}", mod_str), ident_span)
2270 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2272 // Emit special messages for unresolved `Self` and `self`.
2273 if is_self_type(path, ns) {
2274 __diagnostic_used!(E0411);
2275 err.code("E0411".into());
2276 err.span_label(span, "`Self` is only available in traits and impls");
2279 if is_self_value(path, ns) {
2280 __diagnostic_used!(E0424);
2281 err.code("E0424".into());
2282 err.span_label(span, format!("`self` value is only available in \
2283 methods with `self` parameter"));
2287 // Try to lookup the name in more relaxed fashion for better error reporting.
2288 let name = path.last().unwrap().name;
2289 let candidates = this.lookup_import_candidates(name, ns, is_expected);
2290 if !candidates.is_empty() {
2291 let mut module_span = this.current_module.span;
2292 module_span.hi = module_span.lo;
2293 // Report import candidates as help and proceed searching for labels.
2294 show_candidates(&mut err, module_span, &candidates, def.is_some());
2295 } else if is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2296 let enum_candidates = this.lookup_import_candidates(name, ns, is_enum_variant);
2297 let mut enum_candidates = enum_candidates.iter()
2298 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2299 enum_candidates.sort();
2300 for (sp, variant_path, enum_path) in enum_candidates {
2301 let msg = format!("there is an enum variant `{}`, did you mean to use `{}`?",
2307 err.span_help(sp, &msg);
2311 if path.len() == 1 && this.self_type_is_available(span) {
2312 if let Some(candidate) = this.lookup_assoc_candidate(name, ns, is_expected) {
2313 let self_is_available = this.self_value_is_available(path[0].ctxt, span);
2315 AssocSuggestion::Field => {
2316 err.span_label(span, format!("did you mean `self.{}`?", path_str));
2317 if !self_is_available {
2318 err.span_label(span, format!("`self` value is only available in \
2319 methods with `self` parameter"));
2322 AssocSuggestion::MethodWithSelf if self_is_available => {
2323 err.span_label(span, format!("did you mean `self.{}(...)`?",
2326 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2327 err.span_label(span, format!("did you mean `Self::{}`?", path_str));
2334 let mut levenshtein_worked = false;
2337 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2338 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2339 levenshtein_worked = true;
2342 // Try context dependent help if relaxed lookup didn't work.
2343 if let Some(def) = def {
2344 match (def, source) {
2345 (Def::Macro(..), _) => {
2346 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2349 (Def::TyAlias(..), PathSource::Trait) => {
2350 err.span_label(span, "type aliases cannot be used for traits");
2353 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2354 ExprKind::Field(_, ident) => {
2355 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2356 path_str, ident.node));
2359 ExprKind::MethodCall(ident, ..) => {
2360 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2361 path_str, ident.node));
2366 _ if ns == ValueNS && is_struct_like(def) => {
2367 if let Def::Struct(def_id) = def {
2368 if let Some((ctor_def, ctor_vis))
2369 = this.struct_constructors.get(&def_id).cloned() {
2370 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2371 err.span_label(span, format!("constructor is not visible \
2372 here due to private fields"));
2376 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2385 if !levenshtein_worked {
2386 err.span_label(base_span, fallback_label);
2390 let report_errors = |this: &mut Self, def: Option<Def>| {
2391 report_errors(this, def).emit();
2392 err_path_resolution()
2395 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2396 source.defer_to_typeck(),
2397 source.global_by_default()) {
2398 Some(resolution) if resolution.unresolved_segments() == 0 => {
2399 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2402 // Add a temporary hack to smooth the transition to new struct ctor
2403 // visibility rules. See #38932 for more details.
2405 if let Def::Struct(def_id) = resolution.base_def() {
2406 if let Some((ctor_def, ctor_vis))
2407 = self.struct_constructors.get(&def_id).cloned() {
2408 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2409 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2410 self.session.add_lint(lint, id, span,
2411 "private struct constructors are not usable through \
2412 reexports in outer modules".to_string());
2413 res = Some(PathResolution::new(ctor_def));
2418 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2421 Some(resolution) if source.defer_to_typeck() => {
2422 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2423 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2424 // it needs to be added to the trait map.
2426 let item_name = path.last().unwrap().name;
2427 let traits = self.get_traits_containing_item(item_name, ns);
2428 self.trait_map.insert(id, traits);
2432 _ => report_errors(self, None)
2435 if let PathSource::TraitItem(..) = source {} else {
2436 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2437 self.record_def(id, resolution);
2442 fn self_type_is_available(&mut self, span: Span) -> bool {
2443 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2444 TypeNS, false, span);
2445 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2448 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2449 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2450 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2451 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2454 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2455 fn resolve_qpath_anywhere(&mut self,
2457 qself: Option<&QSelf>,
2459 primary_ns: Namespace,
2461 defer_to_typeck: bool,
2462 global_by_default: bool)
2463 -> Option<PathResolution> {
2464 let mut fin_res = None;
2465 // FIXME: can't resolve paths in macro namespace yet, macros are
2466 // processed by the little special hack below.
2467 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2468 if i == 0 || ns != primary_ns {
2469 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2470 // If defer_to_typeck, then resolution > no resolution,
2471 // otherwise full resolution > partial resolution > no resolution.
2472 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2474 res => if fin_res.is_none() { fin_res = res },
2478 let is_global = self.global_macros.get(&path[0].name).cloned()
2479 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2480 if primary_ns != MacroNS && (is_global || self.macro_names.contains(&path[0].name)) {
2481 // Return some dummy definition, it's enough for error reporting.
2483 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2489 /// Handles paths that may refer to associated items.
2490 fn resolve_qpath(&mut self,
2492 qself: Option<&QSelf>,
2496 global_by_default: bool)
2497 -> Option<PathResolution> {
2498 if let Some(qself) = qself {
2499 if qself.position == 0 {
2500 // FIXME: Create some fake resolution that can't possibly be a type.
2501 return Some(PathResolution::with_unresolved_segments(
2502 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2505 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2506 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2507 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2508 span, span, PathSource::TraitItem(ns));
2509 return Some(PathResolution::with_unresolved_segments(
2510 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2514 let result = match self.resolve_path(&path, Some(ns), true, span) {
2515 PathResult::NonModule(path_res) => path_res,
2516 PathResult::Module(module) if !module.is_normal() => {
2517 PathResolution::new(module.def().unwrap())
2519 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2520 // don't report an error right away, but try to fallback to a primitive type.
2521 // So, we are still able to successfully resolve something like
2523 // use std::u8; // bring module u8 in scope
2524 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2525 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2526 // // not to non-existent std::u8::max_value
2529 // Such behavior is required for backward compatibility.
2530 // The same fallback is used when `a` resolves to nothing.
2531 PathResult::Module(..) | PathResult::Failed(..)
2532 if (ns == TypeNS || path.len() > 1) &&
2533 self.primitive_type_table.primitive_types.contains_key(&path[0].name) => {
2534 let prim = self.primitive_type_table.primitive_types[&path[0].name];
2536 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2537 if !self.session.features.borrow().i128_type {
2538 emit_feature_err(&self.session.parse_sess,
2539 "i128_type", span, GateIssue::Language,
2540 "128-bit type is unstable");
2546 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2548 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2549 PathResult::Failed(msg, false) => {
2550 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2551 err_path_resolution()
2553 PathResult::Failed(..) => return None,
2554 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2557 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2558 path[0].name != keywords::CrateRoot.name() && path[0].name != "$crate" {
2559 let unqualified_result = {
2560 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2561 PathResult::NonModule(path_res) => path_res.base_def(),
2562 PathResult::Module(module) => module.def().unwrap(),
2563 _ => return Some(result),
2566 if result.base_def() == unqualified_result {
2567 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2568 self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
2575 fn resolve_path(&mut self,
2577 opt_ns: Option<Namespace>, // `None` indicates a module path
2581 let mut module = None;
2582 let mut allow_super = true;
2584 for (i, &ident) in path.iter().enumerate() {
2585 let is_last = i == path.len() - 1;
2586 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2588 if i == 0 && ns == TypeNS && ident.name == keywords::SelfValue.name() {
2589 module = Some(self.module_map[&self.current_module.normal_ancestor_id]);
2591 } else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() {
2592 let current_module = if i == 0 { self.current_module } else { module.unwrap() };
2593 let self_module = self.module_map[¤t_module.normal_ancestor_id];
2594 if let Some(parent) = self_module.parent {
2595 module = Some(self.module_map[&parent.normal_ancestor_id]);
2598 let msg = "There are too many initial `super`s.".to_string();
2599 return PathResult::Failed(msg, false);
2602 allow_super = false;
2604 if i == 0 && ns == TypeNS && ident.name == keywords::CrateRoot.name() {
2605 module = Some(self.graph_root);
2607 } else if i == 0 && ns == TypeNS && ident.name == "$crate" {
2608 module = Some(self.resolve_crate_var(ident.ctxt, path_span));
2612 let binding = if let Some(module) = module {
2613 self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
2614 } else if opt_ns == Some(MacroNS) {
2615 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
2616 .map(MacroBinding::binding)
2618 match self.resolve_ident_in_lexical_scope(ident, ns, record_used, path_span) {
2619 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2620 Some(LexicalScopeBinding::Def(def))
2621 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2622 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2626 _ => Err(if record_used { Determined } else { Undetermined }),
2632 let def = binding.def();
2633 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2634 if let Some(next_module) = binding.module() {
2635 module = Some(next_module);
2636 } else if def == Def::Err {
2637 return PathResult::NonModule(err_path_resolution());
2638 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2639 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2640 def, path.len() - i - 1
2643 return PathResult::Failed(format!("Not a module `{}`", ident), is_last);
2646 Err(Undetermined) => return PathResult::Indeterminate,
2647 Err(Determined) => {
2648 if let Some(module) = module {
2649 if opt_ns.is_some() && !module.is_normal() {
2650 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2651 module.def().unwrap(), path.len() - i
2655 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2656 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2657 let mut candidates =
2658 self.lookup_import_candidates(ident.name, TypeNS, is_mod);
2659 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2660 if let Some(candidate) = candidates.get(0) {
2661 format!("Did you mean `{}`?", candidate.path)
2663 format!("Maybe a missing `extern crate {};`?", ident)
2666 format!("Use of undeclared type or module `{}`", ident)
2668 format!("Could not find `{}` in `{}`", ident, path[i - 1])
2670 return PathResult::Failed(msg, is_last);
2675 PathResult::Module(module.unwrap_or(self.graph_root))
2678 // Resolve a local definition, potentially adjusting for closures.
2679 fn adjust_local_def(&mut self,
2684 span: Span) -> Def {
2685 let ribs = &self.ribs[ns][rib_index + 1..];
2687 // An invalid forward use of a type parameter from a previous default.
2688 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2690 resolve_error(self, span,
2691 ResolutionError::ForwardDeclaredTyParam);
2693 assert_eq!(def, Def::Err);
2699 span_bug!(span, "unexpected {:?} in bindings", def)
2701 Def::Local(def_id) => {
2704 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2705 ForwardTyParamBanRibKind => {
2706 // Nothing to do. Continue.
2708 ClosureRibKind(function_id) => {
2710 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2712 let seen = self.freevars_seen
2714 .or_insert_with(|| NodeMap());
2715 if let Some(&index) = seen.get(&node_id) {
2716 def = Def::Upvar(def_id, index, function_id);
2719 let vec = self.freevars
2721 .or_insert_with(|| vec![]);
2722 let depth = vec.len();
2723 def = Def::Upvar(def_id, depth, function_id);
2730 seen.insert(node_id, depth);
2733 ItemRibKind | MethodRibKind(_) => {
2734 // This was an attempt to access an upvar inside a
2735 // named function item. This is not allowed, so we
2738 resolve_error(self, span,
2739 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2743 ConstantItemRibKind => {
2744 // Still doesn't deal with upvars
2746 resolve_error(self, span,
2747 ResolutionError::AttemptToUseNonConstantValueInConstant);
2754 Def::TyParam(..) | Def::SelfTy(..) => {
2757 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2758 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind => {
2759 // Nothing to do. Continue.
2762 // This was an attempt to use a type parameter outside
2765 resolve_error(self, span,
2766 ResolutionError::TypeParametersFromOuterFunction);
2770 ConstantItemRibKind => {
2773 resolve_error(self, span,
2774 ResolutionError::OuterTypeParameterContext);
2786 // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
2787 // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
2788 // FIXME #34673: This needs testing.
2789 pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
2790 where F: FnOnce(&mut Resolver<'a>) -> T,
2792 self.with_empty_ribs(|this| {
2793 this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2794 this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2799 fn with_empty_ribs<T, F>(&mut self, f: F) -> T
2800 where F: FnOnce(&mut Resolver<'a>) -> T,
2802 let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
2803 let label_ribs = replace(&mut self.label_ribs, Vec::new());
2805 let result = f(self);
2807 self.label_ribs = label_ribs;
2811 fn lookup_assoc_candidate<FilterFn>(&mut self,
2814 filter_fn: FilterFn)
2815 -> Option<AssocSuggestion>
2816 where FilterFn: Fn(Def) -> bool
2818 fn extract_node_id(t: &Ty) -> Option<NodeId> {
2820 TyKind::Path(None, _) => Some(t.id),
2821 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
2822 // This doesn't handle the remaining `Ty` variants as they are not
2823 // that commonly the self_type, it might be interesting to provide
2824 // support for those in future.
2829 // Fields are generally expected in the same contexts as locals.
2830 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
2831 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
2832 // Look for a field with the same name in the current self_type.
2833 if let Some(resolution) = self.def_map.get(&node_id) {
2834 match resolution.base_def() {
2835 Def::Struct(did) | Def::Union(did)
2836 if resolution.unresolved_segments() == 0 => {
2837 if let Some(field_names) = self.field_names.get(&did) {
2838 if field_names.iter().any(|&field_name| name == field_name) {
2839 return Some(AssocSuggestion::Field);
2849 // Look for associated items in the current trait.
2850 if let Some((trait_did, _)) = self.current_trait_ref {
2851 if let Some(&(def, has_self)) = self.trait_item_map.get(&(trait_did, name, ns)) {
2853 return Some(if has_self {
2854 AssocSuggestion::MethodWithSelf
2856 AssocSuggestion::AssocItem
2865 fn lookup_typo_candidate<FilterFn>(&mut self,
2868 filter_fn: FilterFn,
2871 where FilterFn: Fn(Def) -> bool
2873 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
2874 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
2875 if let Some(binding) = resolution.borrow().binding {
2876 if filter_fn(binding.def()) {
2877 names.push(ident.name);
2883 let mut names = Vec::new();
2884 if path.len() == 1 {
2885 // Search in lexical scope.
2886 // Walk backwards up the ribs in scope and collect candidates.
2887 for rib in self.ribs[ns].iter().rev() {
2888 // Locals and type parameters
2889 for (ident, def) in &rib.bindings {
2890 if filter_fn(*def) {
2891 names.push(ident.name);
2895 if let ModuleRibKind(module) = rib.kind {
2896 // Items from this module
2897 add_module_candidates(module, &mut names);
2899 if let ModuleKind::Block(..) = module.kind {
2900 // We can see through blocks
2902 // Items from the prelude
2903 if let Some(prelude) = self.prelude {
2904 if !module.no_implicit_prelude {
2905 add_module_candidates(prelude, &mut names);
2912 // Add primitive types to the mix
2913 if filter_fn(Def::PrimTy(TyBool)) {
2914 for (name, _) in &self.primitive_type_table.primitive_types {
2919 // Search in module.
2920 let mod_path = &path[..path.len() - 1];
2921 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
2923 add_module_candidates(module, &mut names);
2927 let name = path[path.len() - 1].name;
2928 // Make sure error reporting is deterministic.
2929 names.sort_by_key(|name| name.as_str());
2930 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
2931 Some(found) if found != name => Some(found),
2936 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
2937 where F: FnOnce(&mut Resolver)
2939 if let Some(label) = label {
2940 let def = Def::Label(id);
2941 self.with_label_rib(|this| {
2942 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
2950 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
2951 self.with_resolved_label(label, id, |this| this.visit_block(block));
2954 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
2955 // First, record candidate traits for this expression if it could
2956 // result in the invocation of a method call.
2958 self.record_candidate_traits_for_expr_if_necessary(expr);
2960 // Next, resolve the node.
2962 ExprKind::Path(ref qself, ref path) => {
2963 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
2964 visit::walk_expr(self, expr);
2967 ExprKind::Struct(ref path, ..) => {
2968 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
2969 visit::walk_expr(self, expr);
2972 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
2973 match self.search_label(label.node) {
2975 self.record_def(expr.id, err_path_resolution());
2978 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
2980 Some(def @ Def::Label(_)) => {
2981 // Since this def is a label, it is never read.
2982 self.record_def(expr.id, PathResolution::new(def));
2985 span_bug!(expr.span, "label wasn't mapped to a label def!");
2989 // visit `break` argument if any
2990 visit::walk_expr(self, expr);
2993 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
2994 self.visit_expr(subexpression);
2996 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2997 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
2998 self.visit_block(if_block);
2999 self.ribs[ValueNS].pop();
3001 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3004 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3006 ExprKind::While(ref subexpression, ref block, label) => {
3007 self.with_resolved_label(label, expr.id, |this| {
3008 this.visit_expr(subexpression);
3009 this.visit_block(block);
3013 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3014 self.with_resolved_label(label, expr.id, |this| {
3015 this.visit_expr(subexpression);
3016 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3017 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3018 this.visit_block(block);
3019 this.ribs[ValueNS].pop();
3023 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3024 self.visit_expr(subexpression);
3025 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3026 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3028 self.resolve_labeled_block(label, expr.id, block);
3030 self.ribs[ValueNS].pop();
3033 // Equivalent to `visit::walk_expr` + passing some context to children.
3034 ExprKind::Field(ref subexpression, _) => {
3035 self.resolve_expr(subexpression, Some(expr));
3037 ExprKind::MethodCall(_, ref types, ref arguments) => {
3038 let mut arguments = arguments.iter();
3039 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3040 for argument in arguments {
3041 self.resolve_expr(argument, None);
3043 for ty in types.iter() {
3048 ExprKind::Repeat(ref element, ref count) => {
3049 self.visit_expr(element);
3050 self.with_constant_rib(|this| {
3051 this.visit_expr(count);
3054 ExprKind::Call(ref callee, ref arguments) => {
3055 self.resolve_expr(callee, Some(expr));
3056 for argument in arguments {
3057 self.resolve_expr(argument, None);
3062 visit::walk_expr(self, expr);
3067 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3069 ExprKind::Field(_, name) => {
3070 // FIXME(#6890): Even though you can't treat a method like a
3071 // field, we need to add any trait methods we find that match
3072 // the field name so that we can do some nice error reporting
3073 // later on in typeck.
3074 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3075 self.trait_map.insert(expr.id, traits);
3077 ExprKind::MethodCall(name, ..) => {
3078 debug!("(recording candidate traits for expr) recording traits for {}",
3080 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3081 self.trait_map.insert(expr.id, traits);
3089 fn get_traits_containing_item(&mut self, name: Name, ns: Namespace) -> Vec<TraitCandidate> {
3090 debug!("(getting traits containing item) looking for '{}'", name);
3092 let mut found_traits = Vec::new();
3093 // Look for the current trait.
3094 if let Some((trait_def_id, _)) = self.current_trait_ref {
3095 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3096 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: None });
3100 let mut search_module = self.current_module;
3102 self.get_traits_in_module_containing_item(name, ns, search_module, &mut found_traits);
3103 match search_module.kind {
3104 ModuleKind::Block(..) => search_module = search_module.parent.unwrap(),
3109 if let Some(prelude) = self.prelude {
3110 if !search_module.no_implicit_prelude {
3111 self.get_traits_in_module_containing_item(name, ns, prelude, &mut found_traits);
3118 fn get_traits_in_module_containing_item(&mut self,
3122 found_traits: &mut Vec<TraitCandidate>) {
3123 let mut traits = module.traits.borrow_mut();
3124 if traits.is_none() {
3125 let mut collected_traits = Vec::new();
3126 module.for_each_child(|name, ns, binding| {
3127 if ns != TypeNS { return }
3128 if let Def::Trait(_) = binding.def() {
3129 collected_traits.push((name, binding));
3132 *traits = Some(collected_traits.into_boxed_slice());
3135 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3136 let trait_def_id = binding.def().def_id();
3137 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3138 let import_id = match binding.kind {
3139 NameBindingKind::Import { directive, .. } => {
3140 self.maybe_unused_trait_imports.insert(directive.id);
3141 self.add_to_glob_map(directive.id, trait_name);
3146 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3151 /// When name resolution fails, this method can be used to look up candidate
3152 /// entities with the expected name. It allows filtering them using the
3153 /// supplied predicate (which should be used to only accept the types of
3154 /// definitions expected e.g. traits). The lookup spans across all crates.
3156 /// NOTE: The method does not look into imports, but this is not a problem,
3157 /// since we report the definitions (thus, the de-aliased imports).
3158 fn lookup_import_candidates<FilterFn>(&mut self,
3160 namespace: Namespace,
3161 filter_fn: FilterFn)
3162 -> Vec<ImportSuggestion>
3163 where FilterFn: Fn(Def) -> bool
3165 let mut candidates = Vec::new();
3166 let mut worklist = Vec::new();
3167 let mut seen_modules = FxHashSet();
3168 worklist.push((self.graph_root, Vec::new(), false));
3170 while let Some((in_module,
3172 in_module_is_extern)) = worklist.pop() {
3173 self.populate_module_if_necessary(in_module);
3175 in_module.for_each_child(|ident, ns, name_binding| {
3177 // avoid imports entirely
3178 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3179 // avoid non-importable candidates as well
3180 if !name_binding.is_importable() { return; }
3182 // collect results based on the filter function
3183 if ident.name == lookup_name && ns == namespace {
3184 if filter_fn(name_binding.def()) {
3186 let mut segms = path_segments.clone();
3187 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3189 span: name_binding.span,
3192 // the entity is accessible in the following cases:
3193 // 1. if it's defined in the same crate, it's always
3194 // accessible (since private entities can be made public)
3195 // 2. if it's defined in another crate, it's accessible
3196 // only if both the module is public and the entity is
3197 // declared as public (due to pruning, we don't explore
3198 // outside crate private modules => no need to check this)
3199 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3200 candidates.push(ImportSuggestion { path: path });
3205 // collect submodules to explore
3206 if let Some(module) = name_binding.module() {
3208 let mut path_segments = path_segments.clone();
3209 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3211 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3212 // add the module to the lookup
3213 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3214 if seen_modules.insert(module.def_id().unwrap()) {
3215 worklist.push((module, path_segments, is_extern));
3225 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3226 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3227 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3228 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3232 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3234 ast::Visibility::Public => ty::Visibility::Public,
3235 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3236 ast::Visibility::Inherited => {
3237 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3239 ast::Visibility::Restricted { ref path, id } => {
3240 let def = self.smart_resolve_path(id, None, path,
3241 PathSource::Visibility).base_def();
3242 if def == Def::Err {
3243 ty::Visibility::Public
3245 let vis = ty::Visibility::Restricted(def.def_id());
3246 if self.is_accessible(vis) {
3249 self.session.span_err(path.span, "visibilities can only be restricted \
3250 to ancestor modules");
3251 ty::Visibility::Public
3258 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3259 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3262 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3263 vis.is_accessible_from(module.normal_ancestor_id, self)
3266 fn report_errors(&mut self) {
3267 self.report_shadowing_errors();
3268 let mut reported_spans = FxHashSet();
3270 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3271 if !reported_spans.insert(span) { continue }
3272 let participle = |binding: &NameBinding| {
3273 if binding.is_import() { "imported" } else { "defined" }
3275 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3276 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3277 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3278 format!("consider adding an explicit import of `{}` to disambiguate", name)
3279 } else if let Def::Macro(..) = b1.def() {
3280 format!("macro-expanded {} do not shadow",
3281 if b1.is_import() { "macro imports" } else { "macros" })
3283 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3284 if b1.is_import() { "imports" } else { "items" })
3287 let id = match b2.kind {
3288 NameBindingKind::Import { directive, .. } => directive.id,
3289 _ => unreachable!(),
3291 let mut span = MultiSpan::from_span(span);
3292 span.push_span_label(b1.span, msg1);
3293 span.push_span_label(b2.span, msg2);
3294 let msg = format!("`{}` is ambiguous", name);
3295 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3298 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3299 err.span_note(b1.span, &msg1);
3301 Def::Macro(..) if b2.span == DUMMY_SP =>
3302 err.note(&format!("`{}` is also a builtin macro", name)),
3303 _ => err.span_note(b2.span, &msg2),
3305 err.note(¬e).emit();
3309 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3310 if !reported_spans.insert(span) { continue }
3311 if binding.is_extern_crate() {
3312 // Warn when using an inaccessible extern crate.
3313 let node_id = match binding.kind {
3314 NameBindingKind::Import { directive, .. } => directive.id,
3315 _ => unreachable!(),
3317 let msg = format!("extern crate `{}` is private", name);
3318 self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
3320 let def = binding.def();
3321 self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
3326 fn report_shadowing_errors(&mut self) {
3327 for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3328 self.resolve_legacy_scope(scope, name, true);
3331 let mut reported_errors = FxHashSet();
3332 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3333 if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() &&
3334 reported_errors.insert((binding.name, binding.span)) {
3335 let msg = format!("`{}` is already in scope", binding.name);
3336 self.session.struct_span_err(binding.span, &msg)
3337 .note("macro-expanded `macro_rules!`s may not shadow \
3338 existing macros (see RFC 1560)")
3344 fn report_conflict(&mut self,
3348 binding: &NameBinding,
3349 old_binding: &NameBinding) {
3350 // Error on the second of two conflicting names
3351 if old_binding.span.lo > binding.span.lo {
3352 return self.report_conflict(parent, ident, ns, old_binding, binding);
3355 let container = match parent.kind {
3356 ModuleKind::Def(Def::Mod(_), _) => "module",
3357 ModuleKind::Def(Def::Trait(_), _) => "trait",
3358 ModuleKind::Block(..) => "block",
3362 let (participle, noun) = match old_binding.is_import() {
3363 true => ("imported", "import"),
3364 false => ("defined", "definition"),
3367 let (name, span) = (ident.name, binding.span);
3369 if let Some(s) = self.name_already_seen.get(&name) {
3376 let kind = match (ns, old_binding.module()) {
3377 (ValueNS, _) => "a value",
3378 (MacroNS, _) => "a macro",
3379 (TypeNS, _) if old_binding.is_extern_crate() => "an extern crate",
3380 (TypeNS, Some(module)) if module.is_normal() => "a module",
3381 (TypeNS, Some(module)) if module.is_trait() => "a trait",
3382 (TypeNS, _) => "a type",
3384 format!("{} named `{}` has already been {} in this {}",
3385 kind, name, participle, container)
3388 let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
3389 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3390 (true, _) | (_, true) => match binding.is_import() && old_binding.is_import() {
3391 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3392 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3394 _ => match (old_binding.is_import(), binding.is_import()) {
3395 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3396 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3397 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3401 err.span_label(span, format!("`{}` already {}", name, participle));
3402 if old_binding.span != syntax_pos::DUMMY_SP {
3403 err.span_label(old_binding.span, format!("previous {} of `{}` here", noun, name));
3406 self.name_already_seen.insert(name, span);
3409 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3410 let (id, span) = (directive.id, directive.span);
3411 let msg = "`self` no longer imports values".to_string();
3412 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3415 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3416 if self.proc_macro_enabled { return; }
3419 if attr.path.segments.len() > 1 {
3422 let ident = attr.path.segments[0].identifier;
3423 let result = self.resolve_lexical_macro_path_segment(ident,
3427 if let Ok(binding) = result {
3428 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3429 attr::mark_known(attr);
3431 let msg = "attribute procedural macros are experimental";
3432 let feature = "proc_macro";
3434 feature_err(&self.session.parse_sess, feature,
3435 attr.span, GateIssue::Language, msg)
3436 .span_note(binding.span(), "procedural macro imported here")
3444 fn is_struct_like(def: Def) -> bool {
3446 Def::VariantCtor(_, CtorKind::Fictive) => true,
3447 _ => PathSource::Struct.is_expected(def),
3451 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
3452 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
3455 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
3456 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
3459 fn names_to_string(idents: &[Ident]) -> String {
3460 let mut result = String::new();
3461 for (i, ident) in idents.iter().filter(|i| i.name != keywords::CrateRoot.name()).enumerate() {
3463 result.push_str("::");
3465 result.push_str(&ident.name.as_str());
3470 fn path_names_to_string(path: &Path) -> String {
3471 names_to_string(&path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>())
3474 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3475 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3476 let variant_path = &suggestion.path;
3477 let variant_path_string = path_names_to_string(variant_path);
3479 let path_len = suggestion.path.segments.len();
3480 let enum_path = ast::Path {
3481 span: suggestion.path.span,
3482 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3484 let enum_path_string = path_names_to_string(&enum_path);
3486 (suggestion.path.span, variant_path_string, enum_path_string)
3490 /// When an entity with a given name is not available in scope, we search for
3491 /// entities with that name in all crates. This method allows outputting the
3492 /// results of this search in a programmer-friendly way
3493 fn show_candidates(err: &mut DiagnosticBuilder,
3495 candidates: &[ImportSuggestion],
3498 // we want consistent results across executions, but candidates are produced
3499 // by iterating through a hash map, so make sure they are ordered:
3500 let mut path_strings: Vec<_> =
3501 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3502 path_strings.sort();
3504 let better = if better { "better " } else { "" };
3505 let msg_diff = match path_strings.len() {
3506 1 => " is found in another module, you can import it",
3507 _ => "s are found in other modules, you can import them",
3509 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3511 for candidate in &mut path_strings {
3512 *candidate = format!("use {};\n", candidate);
3515 err.span_suggestions(span, &msg, path_strings);
3518 /// A somewhat inefficient routine to obtain the name of a module.
3519 fn module_to_string(module: Module) -> String {
3520 let mut names = Vec::new();
3522 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3523 if let ModuleKind::Def(_, name) = module.kind {
3524 if let Some(parent) = module.parent {
3525 names.push(Ident::with_empty_ctxt(name));
3526 collect_mod(names, parent);
3529 // danger, shouldn't be ident?
3530 names.push(Ident::from_str("<opaque>"));
3531 collect_mod(names, module.parent.unwrap());
3534 collect_mod(&mut names, module);
3536 if names.is_empty() {
3537 return "???".to_string();
3539 names_to_string(&names.into_iter().rev().collect::<Vec<_>>())
3542 fn err_path_resolution() -> PathResolution {
3543 PathResolution::new(Def::Err)
3546 #[derive(PartialEq,Copy, Clone)]
3547 pub enum MakeGlobMap {
3552 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }