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 E0403: the name is already used for a type parameter in this type parameter list
131 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
132 /// error E0407: method is not a member of trait
133 MethodNotMemberOfTrait(Name, &'a str),
134 /// error E0437: type is not a member of trait
135 TypeNotMemberOfTrait(Name, &'a str),
136 /// error E0438: const is not a member of trait
137 ConstNotMemberOfTrait(Name, &'a str),
138 /// error E0408: variable `{}` is not bound in all patterns
139 VariableNotBoundInPattern(&'a BindingError),
140 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
141 VariableBoundWithDifferentMode(Name, Span),
142 /// error E0415: identifier is bound more than once in this parameter list
143 IdentifierBoundMoreThanOnceInParameterList(&'a str),
144 /// error E0416: identifier is bound more than once in the same pattern
145 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
146 /// error E0426: use of undeclared label
147 UndeclaredLabel(&'a str),
148 /// error E0429: `self` imports are only allowed within a { } list
149 SelfImportsOnlyAllowedWithin,
150 /// error E0430: `self` import can only appear once in the list
151 SelfImportCanOnlyAppearOnceInTheList,
152 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
153 SelfImportOnlyInImportListWithNonEmptyPrefix,
154 /// error E0432: unresolved import
155 UnresolvedImport(Option<(&'a str, &'a str)>),
156 /// error E0433: failed to resolve
157 FailedToResolve(&'a str),
158 /// error E0434: can't capture dynamic environment in a fn item
159 CannotCaptureDynamicEnvironmentInFnItem,
160 /// error E0435: attempt to use a non-constant value in a constant
161 AttemptToUseNonConstantValueInConstant,
162 /// error E0530: X bindings cannot shadow Ys
163 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
164 /// error E0128: type parameters with a default cannot use forward declared identifiers
165 ForwardDeclaredTyParam,
168 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
170 resolution_error: ResolutionError<'a>) {
171 resolve_struct_error(resolver, span, resolution_error).emit();
174 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
176 resolution_error: ResolutionError<'a>)
177 -> DiagnosticBuilder<'sess> {
178 match resolution_error {
179 ResolutionError::TypeParametersFromOuterFunction => {
180 let mut err = struct_span_err!(resolver.session,
183 "can't use type parameters from outer function; \
184 try using a local type parameter instead");
185 err.span_label(span, "use of type variable from outer function");
188 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
189 let mut err = struct_span_err!(resolver.session,
192 "the name `{}` is already used for a type parameter \
193 in this type parameter list",
195 err.span_label(span, "already used");
196 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
199 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
200 let mut err = struct_span_err!(resolver.session,
203 "method `{}` is not a member of trait `{}`",
206 err.span_label(span, format!("not a member of trait `{}`", trait_));
209 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
210 let mut err = struct_span_err!(resolver.session,
213 "type `{}` is not a member of trait `{}`",
216 err.span_label(span, format!("not a member of trait `{}`", trait_));
219 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
220 let mut err = struct_span_err!(resolver.session,
223 "const `{}` is not a member of trait `{}`",
226 err.span_label(span, format!("not a member of trait `{}`", trait_));
229 ResolutionError::VariableNotBoundInPattern(binding_error) => {
230 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
231 let msp = MultiSpan::from_spans(target_sp.clone());
232 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
233 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
234 for sp in target_sp {
235 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
237 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
238 for sp in origin_sp {
239 err.span_label(sp, "variable not in all patterns");
243 ResolutionError::VariableBoundWithDifferentMode(variable_name,
244 first_binding_span) => {
245 let mut err = struct_span_err!(resolver.session,
248 "variable `{}` is bound in inconsistent \
249 ways within the same match arm",
251 err.span_label(span, "bound in different ways");
252 err.span_label(first_binding_span, "first binding");
255 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
256 let mut err = struct_span_err!(resolver.session,
259 "identifier `{}` is bound more than once in this parameter list",
261 err.span_label(span, "used as parameter more than once");
264 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
265 let mut err = struct_span_err!(resolver.session,
268 "identifier `{}` is bound more than once in the same pattern",
270 err.span_label(span, "used in a pattern more than once");
273 ResolutionError::UndeclaredLabel(name) => {
274 let mut err = struct_span_err!(resolver.session,
277 "use of undeclared label `{}`",
279 err.span_label(span, format!("undeclared label `{}`", name));
282 ResolutionError::SelfImportsOnlyAllowedWithin => {
283 struct_span_err!(resolver.session,
287 "`self` imports are only allowed within a { } list")
289 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
290 struct_span_err!(resolver.session,
293 "`self` import can only appear once in the list")
295 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
296 struct_span_err!(resolver.session,
299 "`self` import can only appear in an import list with a \
302 ResolutionError::UnresolvedImport(name) => {
303 let msg = match name {
304 Some((n, _)) => format!("unresolved import `{}`", n),
305 None => "unresolved import".to_owned(),
307 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
308 if let Some((_, p)) = name {
309 err.span_label(span, p);
313 ResolutionError::FailedToResolve(msg) => {
314 let mut err = struct_span_err!(resolver.session, span, E0433,
315 "failed to resolve. {}", msg);
316 err.span_label(span, msg);
319 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
320 struct_span_err!(resolver.session,
324 "can't capture dynamic environment in a fn item; use the || { ... } \
325 closure form instead")
327 ResolutionError::AttemptToUseNonConstantValueInConstant => {
328 let mut err = struct_span_err!(resolver.session,
331 "attempt to use a non-constant value in a constant");
332 err.span_label(span, "non-constant used with constant");
335 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
336 let shadows_what = PathResolution::new(binding.def()).kind_name();
337 let mut err = struct_span_err!(resolver.session,
340 "{}s cannot shadow {}s", what_binding, shadows_what);
341 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
342 let participle = if binding.is_import() { "imported" } else { "defined" };
343 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
344 err.span_label(binding.span, msg);
347 ResolutionError::ForwardDeclaredTyParam => {
348 let mut err = struct_span_err!(resolver.session, span, E0128,
349 "type parameters with a default cannot use \
350 forward declared identifiers");
351 err.span_label(span, format!("defaulted type parameters \
352 cannot be forward declared"));
358 #[derive(Copy, Clone, Debug)]
361 binding_mode: BindingMode,
364 // Map from the name in a pattern to its binding mode.
365 type BindingMap = FxHashMap<Ident, BindingInfo>;
367 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
378 fn is_refutable(self) -> bool {
380 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
381 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
384 fn descr(self) -> &'static str {
386 PatternSource::Match => "match binding",
387 PatternSource::IfLet => "if let binding",
388 PatternSource::WhileLet => "while let binding",
389 PatternSource::Let => "let binding",
390 PatternSource::For => "for binding",
391 PatternSource::FnParam => "function parameter",
396 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
397 enum PathSource<'a> {
398 // Type paths `Path`.
400 // Trait paths in bounds or impls.
402 // Expression paths `path`, with optional parent context.
403 Expr(Option<&'a Expr>),
404 // Paths in path patterns `Path`.
406 // Paths in struct expressions and patterns `Path { .. }`.
408 // Paths in tuple struct patterns `Path(..)`.
410 // `m::A::B` in `<T as m::A>::B::C`.
411 TraitItem(Namespace),
412 // Path in `pub(path)`
414 // Path in `use a::b::{...};`
418 impl<'a> PathSource<'a> {
419 fn namespace(self) -> Namespace {
421 PathSource::Type | PathSource::Trait | PathSource::Struct |
422 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
423 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
424 PathSource::TraitItem(ns) => ns,
428 fn global_by_default(self) -> bool {
430 PathSource::Visibility | PathSource::ImportPrefix => true,
431 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
432 PathSource::Struct | PathSource::TupleStruct |
433 PathSource::Trait | PathSource::TraitItem(..) => false,
437 fn defer_to_typeck(self) -> bool {
439 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
440 PathSource::Struct | PathSource::TupleStruct => true,
441 PathSource::Trait | PathSource::TraitItem(..) |
442 PathSource::Visibility | PathSource::ImportPrefix => false,
446 fn descr_expected(self) -> &'static str {
448 PathSource::Type => "type",
449 PathSource::Trait => "trait",
450 PathSource::Pat => "unit struct/variant or constant",
451 PathSource::Struct => "struct, variant or union type",
452 PathSource::TupleStruct => "tuple struct/variant",
453 PathSource::Visibility => "module",
454 PathSource::ImportPrefix => "module or enum",
455 PathSource::TraitItem(ns) => match ns {
456 TypeNS => "associated type",
457 ValueNS => "method or associated constant",
458 MacroNS => bug!("associated macro"),
460 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
461 // "function" here means "anything callable" rather than `Def::Fn`,
462 // this is not precise but usually more helpful than just "value".
463 Some(&ExprKind::Call(..)) => "function",
469 fn is_expected(self, def: Def) -> bool {
471 PathSource::Type => match def {
472 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
473 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
474 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
477 PathSource::Trait => match def {
478 Def::Trait(..) => true,
481 PathSource::Expr(..) => match def {
482 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
483 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
484 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
485 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
488 PathSource::Pat => match def {
489 Def::StructCtor(_, CtorKind::Const) |
490 Def::VariantCtor(_, CtorKind::Const) |
491 Def::Const(..) | Def::AssociatedConst(..) => true,
494 PathSource::TupleStruct => match def {
495 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
498 PathSource::Struct => match def {
499 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
500 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
503 PathSource::TraitItem(ns) => match def {
504 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
505 Def::AssociatedTy(..) if ns == TypeNS => true,
508 PathSource::ImportPrefix => match def {
509 Def::Mod(..) | Def::Enum(..) => true,
512 PathSource::Visibility => match def {
513 Def::Mod(..) => true,
519 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
520 __diagnostic_used!(E0404);
521 __diagnostic_used!(E0405);
522 __diagnostic_used!(E0412);
523 __diagnostic_used!(E0422);
524 __diagnostic_used!(E0423);
525 __diagnostic_used!(E0425);
526 __diagnostic_used!(E0531);
527 __diagnostic_used!(E0532);
528 __diagnostic_used!(E0573);
529 __diagnostic_used!(E0574);
530 __diagnostic_used!(E0575);
531 __diagnostic_used!(E0576);
532 __diagnostic_used!(E0577);
533 __diagnostic_used!(E0578);
534 match (self, has_unexpected_resolution) {
535 (PathSource::Trait, true) => "E0404",
536 (PathSource::Trait, false) => "E0405",
537 (PathSource::Type, true) => "E0573",
538 (PathSource::Type, false) => "E0412",
539 (PathSource::Struct, true) => "E0574",
540 (PathSource::Struct, false) => "E0422",
541 (PathSource::Expr(..), true) => "E0423",
542 (PathSource::Expr(..), false) => "E0425",
543 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
544 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
545 (PathSource::TraitItem(..), true) => "E0575",
546 (PathSource::TraitItem(..), false) => "E0576",
547 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
548 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
553 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
560 #[derive(Clone, Default, Debug)]
561 pub struct PerNS<T> {
567 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
569 fn index(&self, ns: Namespace) -> &T {
571 ValueNS => &self.value_ns,
572 TypeNS => &self.type_ns,
573 MacroNS => self.macro_ns.as_ref().unwrap(),
578 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
579 fn index_mut(&mut self, ns: Namespace) -> &mut T {
581 ValueNS => &mut self.value_ns,
582 TypeNS => &mut self.type_ns,
583 MacroNS => self.macro_ns.as_mut().unwrap(),
588 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
589 fn visit_item(&mut self, item: &'tcx Item) {
590 self.resolve_item(item);
592 fn visit_arm(&mut self, arm: &'tcx Arm) {
593 self.resolve_arm(arm);
595 fn visit_block(&mut self, block: &'tcx Block) {
596 self.resolve_block(block);
598 fn visit_expr(&mut self, expr: &'tcx Expr) {
599 self.resolve_expr(expr, None);
601 fn visit_local(&mut self, local: &'tcx Local) {
602 self.resolve_local(local);
604 fn visit_ty(&mut self, ty: &'tcx Ty) {
605 if let TyKind::Path(ref qself, ref path) = ty.node {
606 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
607 } else if let TyKind::ImplicitSelf = ty.node {
608 let self_ty = keywords::SelfType.ident();
609 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
610 .map_or(Def::Err, |d| d.def());
611 self.record_def(ty.id, PathResolution::new(def));
612 } else if let TyKind::Array(ref element, ref length) = ty.node {
613 self.visit_ty(element);
614 self.with_constant_rib(|this| {
615 this.visit_expr(length);
619 visit::walk_ty(self, ty);
621 fn visit_poly_trait_ref(&mut self,
622 tref: &'tcx ast::PolyTraitRef,
623 m: &'tcx ast::TraitBoundModifier) {
624 self.smart_resolve_path(tref.trait_ref.ref_id, None,
625 &tref.trait_ref.path, PathSource::Trait);
626 visit::walk_poly_trait_ref(self, tref, m);
628 fn visit_variant(&mut self,
629 variant: &'tcx ast::Variant,
630 generics: &'tcx Generics,
631 item_id: ast::NodeId) {
632 if let Some(ref dis_expr) = variant.node.disr_expr {
633 // resolve the discriminator expr as a constant
634 self.with_constant_rib(|this| {
635 this.visit_expr(dis_expr);
639 // `visit::walk_variant` without the discriminant expression.
640 self.visit_variant_data(&variant.node.data,
646 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
647 let type_parameters = match foreign_item.node {
648 ForeignItemKind::Fn(_, ref generics) => {
649 HasTypeParameters(generics, ItemRibKind)
651 ForeignItemKind::Static(..) => NoTypeParameters,
653 self.with_type_parameter_rib(type_parameters, |this| {
654 visit::walk_foreign_item(this, foreign_item);
657 fn visit_fn(&mut self,
658 function_kind: FnKind<'tcx>,
659 declaration: &'tcx FnDecl,
662 let rib_kind = match function_kind {
663 FnKind::ItemFn(_, generics, ..) => {
664 self.visit_generics(generics);
667 FnKind::Method(_, sig, _, _) => {
668 self.visit_generics(&sig.generics);
669 MethodRibKind(!sig.decl.has_self())
671 FnKind::Closure(_) => ClosureRibKind(node_id),
674 // Create a value rib for the function.
675 self.ribs[ValueNS].push(Rib::new(rib_kind));
677 // Create a label rib for the function.
678 self.label_ribs.push(Rib::new(rib_kind));
680 // Add each argument to the rib.
681 let mut bindings_list = FxHashMap();
682 for argument in &declaration.inputs {
683 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
685 self.visit_ty(&argument.ty);
687 debug!("(resolving function) recorded argument");
689 visit::walk_fn_ret_ty(self, &declaration.output);
691 // Resolve the function body.
692 match function_kind {
693 FnKind::ItemFn(.., body) |
694 FnKind::Method(.., body) => {
695 self.visit_block(body);
697 FnKind::Closure(body) => {
698 self.visit_expr(body);
702 debug!("(resolving function) leaving function");
704 self.label_ribs.pop();
705 self.ribs[ValueNS].pop();
707 fn visit_generics(&mut self, generics: &'tcx Generics) {
708 // For type parameter defaults, we have to ban access
709 // to following type parameters, as the Substs can only
710 // provide previous type parameters as they're built.
711 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
712 default_ban_rib.bindings.extend(generics.ty_params.iter()
713 .skip_while(|p| p.default.is_none())
714 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
716 for param in &generics.ty_params {
717 for bound in ¶m.bounds {
718 self.visit_ty_param_bound(bound);
721 if let Some(ref ty) = param.default {
722 self.ribs[TypeNS].push(default_ban_rib);
724 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
727 // Allow all following defaults to refer to this type parameter.
728 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
730 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
731 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
735 pub type ErrorMessage = Option<(Span, String)>;
737 #[derive(Copy, Clone)]
738 enum TypeParameters<'a, 'b> {
740 HasTypeParameters(// Type parameters.
743 // The kind of the rib used for type parameters.
747 // The rib kind controls the translation of local
748 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
749 #[derive(Copy, Clone, Debug)]
751 // No translation needs to be applied.
754 // We passed through a closure scope at the given node ID.
755 // Translate upvars as appropriate.
756 ClosureRibKind(NodeId /* func id */),
758 // We passed through an impl or trait and are now in one of its
759 // methods. Allow references to ty params that impl or trait
760 // binds. Disallow any other upvars (including other ty params that are
763 // The boolean value represents the fact that this method is static or not.
766 // We passed through an item scope. Disallow upvars.
769 // We're in a constant item. Can't refer to dynamic stuff.
772 // We passed through a module.
773 ModuleRibKind(Module<'a>),
775 // We passed through a `macro_rules!` statement
776 MacroDefinition(DefId),
778 // All bindings in this rib are type parameters that can't be used
779 // from the default of a type parameter because they're not declared
780 // before said type parameter. Also see the `visit_generics` override.
781 ForwardTyParamBanRibKind,
787 bindings: FxHashMap<Ident, Def>,
792 fn new(kind: RibKind<'a>) -> Rib<'a> {
794 bindings: FxHashMap(),
800 enum LexicalScopeBinding<'a> {
801 Item(&'a NameBinding<'a>),
805 impl<'a> LexicalScopeBinding<'a> {
806 fn item(self) -> Option<&'a NameBinding<'a>> {
808 LexicalScopeBinding::Item(binding) => Some(binding),
813 fn def(self) -> Def {
815 LexicalScopeBinding::Item(binding) => binding.def(),
816 LexicalScopeBinding::Def(def) => def,
822 enum PathResult<'a> {
824 NonModule(PathResolution),
826 Failed(String, bool /* is the error from the last segment? */),
834 /// One node in the tree of modules.
835 pub struct ModuleData<'a> {
836 parent: Option<Module<'a>>,
839 // The def id of the closest normal module (`mod`) ancestor (including this module).
840 normal_ancestor_id: DefId,
842 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
843 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
844 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
846 // Macro invocations that can expand into items in this module.
847 unresolved_invocations: RefCell<FxHashSet<Mark>>,
849 no_implicit_prelude: bool,
851 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
852 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
854 // Used to memoize the traits in this module for faster searches through all traits in scope.
855 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
857 // Whether this module is populated. If not populated, any attempt to
858 // access the children must be preceded with a
859 // `populate_module_if_necessary` call.
860 populated: Cell<bool>,
862 /// Span of the module itself. Used for error reporting.
866 pub type Module<'a> = &'a ModuleData<'a>;
868 impl<'a> ModuleData<'a> {
869 fn new(parent: Option<Module<'a>>,
871 normal_ancestor_id: DefId,
872 span: Span) -> Self {
876 normal_ancestor_id: normal_ancestor_id,
877 resolutions: RefCell::new(FxHashMap()),
878 legacy_macro_resolutions: RefCell::new(Vec::new()),
879 macro_resolutions: RefCell::new(Vec::new()),
880 unresolved_invocations: RefCell::new(FxHashSet()),
881 no_implicit_prelude: false,
882 glob_importers: RefCell::new(Vec::new()),
883 globs: RefCell::new((Vec::new())),
884 traits: RefCell::new(None),
885 populated: Cell::new(normal_ancestor_id.is_local()),
890 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
891 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
892 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
896 fn def(&self) -> Option<Def> {
898 ModuleKind::Def(def, _) => Some(def),
903 fn def_id(&self) -> Option<DefId> {
904 self.def().as_ref().map(Def::def_id)
907 // `self` resolves to the first module ancestor that `is_normal`.
908 fn is_normal(&self) -> bool {
910 ModuleKind::Def(Def::Mod(_), _) => true,
915 fn is_trait(&self) -> bool {
917 ModuleKind::Def(Def::Trait(_), _) => true,
922 fn is_local(&self) -> bool {
923 self.normal_ancestor_id.is_local()
926 fn nearest_item_scope(&'a self) -> Module<'a> {
927 if self.is_trait() { self.parent.unwrap() } else { self }
931 impl<'a> fmt::Debug for ModuleData<'a> {
932 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
933 write!(f, "{:?}", self.def())
937 // Records a possibly-private value, type, or module definition.
938 #[derive(Clone, Debug)]
939 pub struct NameBinding<'a> {
940 kind: NameBindingKind<'a>,
946 pub trait ToNameBinding<'a> {
947 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
950 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
951 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
956 #[derive(Clone, Debug)]
957 enum NameBindingKind<'a> {
961 binding: &'a NameBinding<'a>,
962 directive: &'a ImportDirective<'a>,
964 legacy_self_import: bool,
967 b1: &'a NameBinding<'a>,
968 b2: &'a NameBinding<'a>,
973 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
975 struct AmbiguityError<'a> {
979 b1: &'a NameBinding<'a>,
980 b2: &'a NameBinding<'a>,
984 impl<'a> NameBinding<'a> {
985 fn module(&self) -> Option<Module<'a>> {
987 NameBindingKind::Module(module) => Some(module),
988 NameBindingKind::Import { binding, .. } => binding.module(),
989 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
994 fn def(&self) -> Def {
996 NameBindingKind::Def(def) => def,
997 NameBindingKind::Module(module) => module.def().unwrap(),
998 NameBindingKind::Import { binding, .. } => binding.def(),
999 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1000 NameBindingKind::Ambiguity { .. } => Def::Err,
1004 fn def_ignoring_ambiguity(&self) -> Def {
1006 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1007 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1012 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
1013 resolver.get_macro(self.def_ignoring_ambiguity())
1016 // We sometimes need to treat variants as `pub` for backwards compatibility
1017 fn pseudo_vis(&self) -> ty::Visibility {
1018 if self.is_variant() { ty::Visibility::Public } else { self.vis }
1021 fn is_variant(&self) -> bool {
1023 NameBindingKind::Def(Def::Variant(..)) |
1024 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1029 fn is_extern_crate(&self) -> bool {
1031 NameBindingKind::Import {
1032 directive: &ImportDirective {
1033 subclass: ImportDirectiveSubclass::ExternCrate, ..
1040 fn is_import(&self) -> bool {
1042 NameBindingKind::Import { .. } => true,
1047 fn is_glob_import(&self) -> bool {
1049 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1050 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1055 fn is_importable(&self) -> bool {
1057 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1062 fn is_macro_def(&self) -> bool {
1064 NameBindingKind::Def(Def::Macro(..)) => true,
1070 /// Interns the names of the primitive types.
1071 struct PrimitiveTypeTable {
1072 primitive_types: FxHashMap<Name, PrimTy>,
1075 impl PrimitiveTypeTable {
1076 fn new() -> PrimitiveTypeTable {
1077 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1079 table.intern("bool", TyBool);
1080 table.intern("char", TyChar);
1081 table.intern("f32", TyFloat(FloatTy::F32));
1082 table.intern("f64", TyFloat(FloatTy::F64));
1083 table.intern("isize", TyInt(IntTy::Is));
1084 table.intern("i8", TyInt(IntTy::I8));
1085 table.intern("i16", TyInt(IntTy::I16));
1086 table.intern("i32", TyInt(IntTy::I32));
1087 table.intern("i64", TyInt(IntTy::I64));
1088 table.intern("i128", TyInt(IntTy::I128));
1089 table.intern("str", TyStr);
1090 table.intern("usize", TyUint(UintTy::Us));
1091 table.intern("u8", TyUint(UintTy::U8));
1092 table.intern("u16", TyUint(UintTy::U16));
1093 table.intern("u32", TyUint(UintTy::U32));
1094 table.intern("u64", TyUint(UintTy::U64));
1095 table.intern("u128", TyUint(UintTy::U128));
1099 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1100 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1104 /// The main resolver class.
1105 pub struct Resolver<'a> {
1106 session: &'a Session,
1108 pub definitions: Definitions,
1110 graph_root: Module<'a>,
1112 prelude: Option<Module<'a>>,
1114 // n.b. This is used only for better diagnostics, not name resolution itself.
1115 has_self: FxHashSet<DefId>,
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<(Module<'a>, 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 // List of crate local macros that we need to warn about as being unused.
1199 // Right now this only includes macro_rules! macros.
1200 unused_macros: FxHashSet<DefId>,
1202 // Maps the `Mark` of an expansion to its containing module or block.
1203 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1205 // Avoid duplicated errors for "name already defined".
1206 name_already_seen: FxHashMap<Name, Span>,
1208 // If `#![feature(proc_macro)]` is set
1209 proc_macro_enabled: bool,
1211 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1212 warned_proc_macros: FxHashSet<Name>,
1214 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1216 // This table maps struct IDs into struct constructor IDs,
1217 // it's not used during normal resolution, only for better error reporting.
1218 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1221 pub struct ResolverArenas<'a> {
1222 modules: arena::TypedArena<ModuleData<'a>>,
1223 local_modules: RefCell<Vec<Module<'a>>>,
1224 name_bindings: arena::TypedArena<NameBinding<'a>>,
1225 import_directives: arena::TypedArena<ImportDirective<'a>>,
1226 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1227 invocation_data: arena::TypedArena<InvocationData<'a>>,
1228 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1231 impl<'a> ResolverArenas<'a> {
1232 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1233 let module = self.modules.alloc(module);
1234 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1235 self.local_modules.borrow_mut().push(module);
1239 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1240 self.local_modules.borrow()
1242 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1243 self.name_bindings.alloc(name_binding)
1245 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1246 -> &'a ImportDirective {
1247 self.import_directives.alloc(import_directive)
1249 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1250 self.name_resolutions.alloc(Default::default())
1252 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1253 -> &'a InvocationData<'a> {
1254 self.invocation_data.alloc(expansion_data)
1256 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1257 self.legacy_bindings.alloc(binding)
1261 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1262 fn parent(self, id: DefId) -> Option<DefId> {
1264 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1265 _ => self.session.cstore.def_key(id).parent,
1266 }.map(|index| DefId { index: index, ..id })
1270 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1271 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1272 let namespace = if is_value { ValueNS } else { TypeNS };
1273 let hir::Path { ref segments, span, ref mut def } = *path;
1274 let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect();
1275 match self.resolve_path(&path, Some(namespace), true, span) {
1276 PathResult::Module(module) => *def = module.def().unwrap(),
1277 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1278 *def = path_res.base_def(),
1279 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1280 PathResult::Failed(msg, _) => {
1281 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1285 PathResult::Indeterminate => unreachable!(),
1286 PathResult::Failed(msg, _) => {
1287 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1292 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1293 self.def_map.get(&id).cloned()
1296 fn definitions(&mut self) -> &mut Definitions {
1297 &mut self.definitions
1301 impl<'a> Resolver<'a> {
1302 pub fn new(session: &'a Session,
1305 make_glob_map: MakeGlobMap,
1306 crate_loader: &'a mut CrateLoader,
1307 arenas: &'a ResolverArenas<'a>)
1309 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1310 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1311 let graph_root = arenas.alloc_module(ModuleData {
1312 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1313 ..ModuleData::new(None, root_module_kind, root_def_id, krate.span)
1315 let mut module_map = FxHashMap();
1316 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1318 let mut definitions = Definitions::new();
1319 DefCollector::new(&mut definitions)
1320 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1322 let mut invocations = FxHashMap();
1323 invocations.insert(Mark::root(),
1324 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1326 let features = session.features.borrow();
1328 let mut macro_defs = FxHashMap();
1329 macro_defs.insert(Mark::root(), root_def_id);
1334 definitions: definitions,
1336 // The outermost module has def ID 0; this is not reflected in the
1338 graph_root: graph_root,
1341 has_self: FxHashSet(),
1342 field_names: FxHashMap(),
1344 determined_imports: Vec::new(),
1345 indeterminate_imports: Vec::new(),
1347 current_module: graph_root,
1349 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1350 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1351 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1353 label_ribs: Vec::new(),
1355 current_trait_ref: None,
1356 current_self_type: None,
1358 primitive_type_table: PrimitiveTypeTable::new(),
1361 freevars: NodeMap(),
1362 freevars_seen: NodeMap(),
1363 export_map: NodeMap(),
1364 trait_map: NodeMap(),
1365 module_map: module_map,
1366 block_map: NodeMap(),
1367 extern_crate_roots: FxHashMap(),
1369 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1370 glob_map: NodeMap(),
1372 used_imports: FxHashSet(),
1373 maybe_unused_trait_imports: NodeSet(),
1375 privacy_errors: Vec::new(),
1376 ambiguity_errors: Vec::new(),
1377 gated_errors: FxHashSet(),
1378 disallowed_shadowing: Vec::new(),
1381 dummy_binding: arenas.alloc_name_binding(NameBinding {
1382 kind: NameBindingKind::Def(Def::Err),
1383 expansion: Mark::root(),
1385 vis: ty::Visibility::Public,
1388 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1390 features.use_extern_macros || features.proc_macro || features.decl_macro,
1392 crate_loader: crate_loader,
1393 macro_names: FxHashSet(),
1394 global_macros: FxHashMap(),
1395 lexical_macro_resolutions: Vec::new(),
1396 macro_map: FxHashMap(),
1397 macro_exports: Vec::new(),
1398 invocations: invocations,
1399 macro_defs: macro_defs,
1400 local_macro_def_scopes: FxHashMap(),
1401 name_already_seen: FxHashMap(),
1402 whitelisted_legacy_custom_derives: Vec::new(),
1403 proc_macro_enabled: features.proc_macro,
1404 warned_proc_macros: FxHashSet(),
1405 potentially_unused_imports: Vec::new(),
1406 struct_constructors: DefIdMap(),
1407 found_unresolved_macro: false,
1408 unused_macros: FxHashSet(),
1412 pub fn arenas() -> ResolverArenas<'a> {
1414 modules: arena::TypedArena::new(),
1415 local_modules: RefCell::new(Vec::new()),
1416 name_bindings: arena::TypedArena::new(),
1417 import_directives: arena::TypedArena::new(),
1418 name_resolutions: arena::TypedArena::new(),
1419 invocation_data: arena::TypedArena::new(),
1420 legacy_bindings: arena::TypedArena::new(),
1424 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1426 type_ns: f(self, TypeNS),
1427 value_ns: f(self, ValueNS),
1428 macro_ns: match self.use_extern_macros {
1429 true => Some(f(self, MacroNS)),
1435 /// Entry point to crate resolution.
1436 pub fn resolve_crate(&mut self, krate: &Crate) {
1437 ImportResolver { resolver: self }.finalize_imports();
1438 self.current_module = self.graph_root;
1439 self.finalize_current_module_macro_resolutions();
1440 visit::walk_crate(self, krate);
1442 check_unused::check_crate(self, krate);
1443 self.report_errors();
1444 self.crate_loader.postprocess(krate);
1451 normal_ancestor_id: DefId,
1454 self.arenas.alloc_module(ModuleData::new(Some(parent), kind, normal_ancestor_id, span))
1457 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1458 -> bool /* true if an error was reported */ {
1459 match binding.kind {
1460 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1463 directive.used.set(true);
1464 if legacy_self_import {
1465 self.warn_legacy_self_import(directive);
1468 self.used_imports.insert((directive.id, ns));
1469 self.add_to_glob_map(directive.id, ident);
1470 self.record_use(ident, ns, binding, span)
1472 NameBindingKind::Import { .. } => false,
1473 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1474 self.ambiguity_errors.push(AmbiguityError {
1475 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
1478 self.record_use(ident, ns, b1, span);
1486 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1487 if self.make_glob_map {
1488 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1492 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1493 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1494 /// `ident` in the first scope that defines it (or None if no scopes define it).
1496 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1497 /// the items are defined in the block. For example,
1500 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1503 /// g(); // This resolves to the local variable `g` since it shadows the item.
1507 /// Invariant: This must only be called during main resolution, not during
1508 /// import resolution.
1509 fn resolve_ident_in_lexical_scope(&mut self,
1514 -> Option<LexicalScopeBinding<'a>> {
1516 ident = ident.unhygienize();
1519 // Walk backwards up the ribs in scope.
1520 for i in (0 .. self.ribs[ns].len()).rev() {
1521 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1522 // The ident resolves to a type parameter or local variable.
1523 return Some(LexicalScopeBinding::Def(
1524 self.adjust_local_def(ns, i, def, record_used, path_span)
1528 if let ModuleRibKind(module) = self.ribs[ns][i].kind {
1529 let item = self.resolve_ident_in_module(module, ident, ns, false,
1530 record_used, path_span);
1531 if let Ok(binding) = item {
1532 // The ident resolves to an item.
1533 return Some(LexicalScopeBinding::Item(binding));
1536 if let ModuleKind::Block(..) = module.kind { // We can see through blocks
1537 } else if !module.no_implicit_prelude {
1538 return self.prelude.and_then(|prelude| {
1539 self.resolve_ident_in_module(prelude, ident, ns, false,
1540 false, path_span).ok()
1541 }).map(LexicalScopeBinding::Item)
1547 if let MacroDefinition(def) = self.ribs[ns][i].kind {
1548 // If an invocation of this macro created `ident`, give up on `ident`
1549 // and switch to `ident`'s source from the macro definition.
1550 let ctxt_data = ident.ctxt.data();
1551 if def == self.macro_defs[&ctxt_data.outer_mark] {
1552 ident.ctxt = ctxt_data.prev_ctxt;
1560 fn resolve_crate_var(&mut self, crate_var_ctxt: SyntaxContext, span: Span) -> Module<'a> {
1561 let mut ctxt_data = crate_var_ctxt.data();
1562 while ctxt_data.prev_ctxt != SyntaxContext::empty() {
1563 ctxt_data = ctxt_data.prev_ctxt.data();
1565 let module = self.macro_def_scope(ctxt_data.outer_mark, span);
1566 if module.is_local() { self.graph_root } else { module }
1571 // We maintain a list of value ribs and type ribs.
1573 // Simultaneously, we keep track of the current position in the module
1574 // graph in the `current_module` pointer. When we go to resolve a name in
1575 // the value or type namespaces, we first look through all the ribs and
1576 // then query the module graph. When we resolve a name in the module
1577 // namespace, we can skip all the ribs (since nested modules are not
1578 // allowed within blocks in Rust) and jump straight to the current module
1581 // Named implementations are handled separately. When we find a method
1582 // call, we consult the module node to find all of the implementations in
1583 // scope. This information is lazily cached in the module node. We then
1584 // generate a fake "implementation scope" containing all the
1585 // implementations thus found, for compatibility with old resolve pass.
1587 fn with_scope<F>(&mut self, id: NodeId, f: F)
1588 where F: FnOnce(&mut Resolver)
1590 let id = self.definitions.local_def_id(id);
1591 let module = self.module_map.get(&id).cloned(); // clones a reference
1592 if let Some(module) = module {
1593 // Move down in the graph.
1594 let orig_module = replace(&mut self.current_module, module);
1595 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1596 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1598 self.finalize_current_module_macro_resolutions();
1601 self.current_module = orig_module;
1602 self.ribs[ValueNS].pop();
1603 self.ribs[TypeNS].pop();
1609 /// Searches the current set of local scopes for labels.
1610 /// Stops after meeting a closure.
1611 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1612 for rib in self.label_ribs.iter().rev() {
1617 MacroDefinition(def) => {
1618 // If an invocation of this macro created `ident`, give up on `ident`
1619 // and switch to `ident`'s source from the macro definition.
1620 let ctxt_data = ident.ctxt.data();
1621 if def == self.macro_defs[&ctxt_data.outer_mark] {
1622 ident.ctxt = ctxt_data.prev_ctxt;
1626 // Do not resolve labels across function boundary
1630 let result = rib.bindings.get(&ident).cloned();
1631 if result.is_some() {
1638 fn resolve_item(&mut self, item: &Item) {
1639 let name = item.ident.name;
1641 debug!("(resolving item) resolving {}", name);
1643 self.check_proc_macro_attrs(&item.attrs);
1646 ItemKind::Enum(_, ref generics) |
1647 ItemKind::Ty(_, ref generics) |
1648 ItemKind::Struct(_, ref generics) |
1649 ItemKind::Union(_, ref generics) |
1650 ItemKind::Fn(.., ref generics, _) => {
1651 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1652 |this| visit::walk_item(this, item));
1655 ItemKind::DefaultImpl(_, ref trait_ref) => {
1656 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1657 // Resolve type arguments in trait path
1658 visit::walk_trait_ref(this, trait_ref);
1661 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1662 self.resolve_implementation(generics,
1668 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1669 // Create a new rib for the trait-wide type parameters.
1670 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1671 let local_def_id = this.definitions.local_def_id(item.id);
1672 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1673 this.visit_generics(generics);
1674 walk_list!(this, visit_ty_param_bound, bounds);
1676 for trait_item in trait_items {
1677 this.check_proc_macro_attrs(&trait_item.attrs);
1679 match trait_item.node {
1680 TraitItemKind::Const(ref ty, ref default) => {
1683 // Only impose the restrictions of
1684 // ConstRibKind for an actual constant
1685 // expression in a provided default.
1686 if let Some(ref expr) = *default{
1687 this.with_constant_rib(|this| {
1688 this.visit_expr(expr);
1692 TraitItemKind::Method(ref sig, _) => {
1693 let type_parameters =
1694 HasTypeParameters(&sig.generics,
1695 MethodRibKind(!sig.decl.has_self()));
1696 this.with_type_parameter_rib(type_parameters, |this| {
1697 visit::walk_trait_item(this, trait_item)
1700 TraitItemKind::Type(..) => {
1701 this.with_type_parameter_rib(NoTypeParameters, |this| {
1702 visit::walk_trait_item(this, trait_item)
1705 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1712 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1713 self.with_scope(item.id, |this| {
1714 visit::walk_item(this, item);
1718 ItemKind::Static(ref ty, _, ref expr) |
1719 ItemKind::Const(ref ty, ref expr) => {
1720 self.with_item_rib(|this| {
1722 this.with_constant_rib(|this| {
1723 this.visit_expr(expr);
1728 ItemKind::Use(ref view_path) => {
1729 match view_path.node {
1730 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1731 // Resolve prefix of an import with empty braces (issue #28388).
1732 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1738 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1739 // do nothing, these are just around to be encoded
1742 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1746 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1747 where F: FnOnce(&mut Resolver)
1749 match type_parameters {
1750 HasTypeParameters(generics, rib_kind) => {
1751 let mut function_type_rib = Rib::new(rib_kind);
1752 let mut seen_bindings = FxHashMap();
1753 for type_parameter in &generics.ty_params {
1754 let ident = type_parameter.ident.unhygienize();
1755 debug!("with_type_parameter_rib: {}", type_parameter.id);
1757 if seen_bindings.contains_key(&ident) {
1758 let span = seen_bindings.get(&ident).unwrap();
1760 ResolutionError::NameAlreadyUsedInTypeParameterList(ident.name, span);
1761 resolve_error(self, type_parameter.span, err);
1763 seen_bindings.entry(ident).or_insert(type_parameter.span);
1765 // plain insert (no renaming)
1766 let def_id = self.definitions.local_def_id(type_parameter.id);
1767 let def = Def::TyParam(def_id);
1768 function_type_rib.bindings.insert(ident, def);
1769 self.record_def(type_parameter.id, PathResolution::new(def));
1771 self.ribs[TypeNS].push(function_type_rib);
1774 NoTypeParameters => {
1781 if let HasTypeParameters(..) = type_parameters {
1782 self.ribs[TypeNS].pop();
1786 fn with_label_rib<F>(&mut self, f: F)
1787 where F: FnOnce(&mut Resolver)
1789 self.label_ribs.push(Rib::new(NormalRibKind));
1791 self.label_ribs.pop();
1794 fn with_item_rib<F>(&mut self, f: F)
1795 where F: FnOnce(&mut Resolver)
1797 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
1798 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
1800 self.ribs[TypeNS].pop();
1801 self.ribs[ValueNS].pop();
1804 fn with_constant_rib<F>(&mut self, f: F)
1805 where F: FnOnce(&mut Resolver)
1807 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1809 self.ribs[ValueNS].pop();
1812 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1813 where F: FnOnce(&mut Resolver) -> T
1815 // Handle nested impls (inside fn bodies)
1816 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1817 let result = f(self);
1818 self.current_self_type = previous_value;
1822 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1823 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1825 let mut new_val = None;
1826 let mut new_id = None;
1827 if let Some(trait_ref) = opt_trait_ref {
1828 let path: Vec<_> = trait_ref.path.segments.iter().map(|seg| seg.identifier).collect();
1829 let def = self.smart_resolve_path_fragment(trait_ref.ref_id,
1832 trait_ref.path.span,
1833 trait_ref.path.segments.last().unwrap().span,
1836 if def != Def::Err {
1837 new_id = Some(def.def_id());
1838 let span = trait_ref.path.span;
1839 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span) {
1840 new_val = Some((module, trait_ref.clone()));
1844 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1845 let result = f(self, new_id);
1846 self.current_trait_ref = original_trait_ref;
1850 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1851 where F: FnOnce(&mut Resolver)
1853 let mut self_type_rib = Rib::new(NormalRibKind);
1855 // plain insert (no renaming, types are not currently hygienic....)
1856 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
1857 self.ribs[TypeNS].push(self_type_rib);
1859 self.ribs[TypeNS].pop();
1862 fn resolve_implementation(&mut self,
1863 generics: &Generics,
1864 opt_trait_reference: &Option<TraitRef>,
1867 impl_items: &[ImplItem]) {
1868 // If applicable, create a rib for the type parameters.
1869 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1870 // Dummy self type for better errors if `Self` is used in the trait path.
1871 this.with_self_rib(Def::SelfTy(None, None), |this| {
1872 // Resolve the trait reference, if necessary.
1873 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1874 let item_def_id = this.definitions.local_def_id(item_id);
1875 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
1876 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1877 // Resolve type arguments in trait path
1878 visit::walk_trait_ref(this, trait_ref);
1880 // Resolve the self type.
1881 this.visit_ty(self_type);
1882 // Resolve the type parameters.
1883 this.visit_generics(generics);
1884 this.with_current_self_type(self_type, |this| {
1885 for impl_item in impl_items {
1886 this.check_proc_macro_attrs(&impl_item.attrs);
1887 this.resolve_visibility(&impl_item.vis);
1888 match impl_item.node {
1889 ImplItemKind::Const(..) => {
1890 // If this is a trait impl, ensure the const
1892 this.check_trait_item(impl_item.ident,
1895 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
1896 visit::walk_impl_item(this, impl_item);
1898 ImplItemKind::Method(ref sig, _) => {
1899 // If this is a trait impl, ensure the method
1901 this.check_trait_item(impl_item.ident,
1904 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
1906 // We also need a new scope for the method-
1907 // specific type parameters.
1908 let type_parameters =
1909 HasTypeParameters(&sig.generics,
1910 MethodRibKind(!sig.decl.has_self()));
1911 this.with_type_parameter_rib(type_parameters, |this| {
1912 visit::walk_impl_item(this, impl_item);
1915 ImplItemKind::Type(ref ty) => {
1916 // If this is a trait impl, ensure the type
1918 this.check_trait_item(impl_item.ident,
1921 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
1925 ImplItemKind::Macro(_) =>
1926 panic!("unexpanded macro in resolve!"),
1936 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
1937 where F: FnOnce(Name, &str) -> ResolutionError
1939 // If there is a TraitRef in scope for an impl, then the method must be in the
1941 if let Some((module, _)) = self.current_trait_ref {
1942 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
1943 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
1944 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
1949 fn resolve_local(&mut self, local: &Local) {
1950 // Resolve the type.
1951 walk_list!(self, visit_ty, &local.ty);
1953 // Resolve the initializer.
1954 walk_list!(self, visit_expr, &local.init);
1956 // Resolve the pattern.
1957 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
1960 // build a map from pattern identifiers to binding-info's.
1961 // this is done hygienically. This could arise for a macro
1962 // that expands into an or-pattern where one 'x' was from the
1963 // user and one 'x' came from the macro.
1964 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
1965 let mut binding_map = FxHashMap();
1967 pat.walk(&mut |pat| {
1968 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
1969 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
1970 Some(Def::Local(..)) => true,
1973 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
1974 binding_map.insert(ident.node, binding_info);
1983 // check that all of the arms in an or-pattern have exactly the
1984 // same set of bindings, with the same binding modes for each.
1985 fn check_consistent_bindings(&mut self, arm: &Arm) {
1986 if arm.pats.is_empty() {
1990 let mut missing_vars = FxHashMap();
1991 let mut inconsistent_vars = FxHashMap();
1992 for (i, p) in arm.pats.iter().enumerate() {
1993 let map_i = self.binding_mode_map(&p);
1995 for (j, q) in arm.pats.iter().enumerate() {
2000 let map_j = self.binding_mode_map(&q);
2001 for (&key, &binding_i) in &map_i {
2002 if map_j.len() == 0 { // Account for missing bindings when
2003 let binding_error = missing_vars // map_j has none.
2005 .or_insert(BindingError {
2007 origin: BTreeSet::new(),
2008 target: BTreeSet::new(),
2010 binding_error.origin.insert(binding_i.span);
2011 binding_error.target.insert(q.span);
2013 for (&key_j, &binding_j) in &map_j {
2014 match map_i.get(&key_j) {
2015 None => { // missing binding
2016 let binding_error = missing_vars
2018 .or_insert(BindingError {
2020 origin: BTreeSet::new(),
2021 target: BTreeSet::new(),
2023 binding_error.origin.insert(binding_j.span);
2024 binding_error.target.insert(p.span);
2026 Some(binding_i) => { // check consistent binding
2027 if binding_i.binding_mode != binding_j.binding_mode {
2030 .or_insert((binding_j.span, binding_i.span));
2038 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2039 missing_vars.sort();
2040 for (_, v) in missing_vars {
2042 *v.origin.iter().next().unwrap(),
2043 ResolutionError::VariableNotBoundInPattern(v));
2045 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2046 inconsistent_vars.sort();
2047 for (name, v) in inconsistent_vars {
2048 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2052 fn resolve_arm(&mut self, arm: &Arm) {
2053 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2055 let mut bindings_list = FxHashMap();
2056 for pattern in &arm.pats {
2057 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2060 // This has to happen *after* we determine which
2061 // pat_idents are variants
2062 self.check_consistent_bindings(arm);
2064 walk_list!(self, visit_expr, &arm.guard);
2065 self.visit_expr(&arm.body);
2067 self.ribs[ValueNS].pop();
2070 fn resolve_block(&mut self, block: &Block) {
2071 debug!("(resolving block) entering block");
2072 // Move down in the graph, if there's an anonymous module rooted here.
2073 let orig_module = self.current_module;
2074 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2076 let mut num_macro_definition_ribs = 0;
2077 if let Some(anonymous_module) = anonymous_module {
2078 debug!("(resolving block) found anonymous module, moving down");
2079 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2080 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2081 self.current_module = anonymous_module;
2082 self.finalize_current_module_macro_resolutions();
2084 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2087 // Descend into the block.
2088 for stmt in &block.stmts {
2089 if let ast::StmtKind::Item(ref item) = stmt.node {
2090 if let ast::ItemKind::MacroDef(..) = item.node {
2091 num_macro_definition_ribs += 1;
2092 let def = self.definitions.local_def_id(item.id);
2093 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2094 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2098 self.visit_stmt(stmt);
2102 self.current_module = orig_module;
2103 for _ in 0 .. num_macro_definition_ribs {
2104 self.ribs[ValueNS].pop();
2105 self.label_ribs.pop();
2107 self.ribs[ValueNS].pop();
2108 if let Some(_) = anonymous_module {
2109 self.ribs[TypeNS].pop();
2111 debug!("(resolving block) leaving block");
2114 fn fresh_binding(&mut self,
2115 ident: &SpannedIdent,
2117 outer_pat_id: NodeId,
2118 pat_src: PatternSource,
2119 bindings: &mut FxHashMap<Ident, NodeId>)
2121 // Add the binding to the local ribs, if it
2122 // doesn't already exist in the bindings map. (We
2123 // must not add it if it's in the bindings map
2124 // because that breaks the assumptions later
2125 // passes make about or-patterns.)
2126 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2127 match bindings.get(&ident.node).cloned() {
2128 Some(id) if id == outer_pat_id => {
2129 // `Variant(a, a)`, error
2133 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2134 &ident.node.name.as_str())
2137 Some(..) if pat_src == PatternSource::FnParam => {
2138 // `fn f(a: u8, a: u8)`, error
2142 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2143 &ident.node.name.as_str())
2146 Some(..) if pat_src == PatternSource::Match => {
2147 // `Variant1(a) | Variant2(a)`, ok
2148 // Reuse definition from the first `a`.
2149 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2152 span_bug!(ident.span, "two bindings with the same name from \
2153 unexpected pattern source {:?}", pat_src);
2156 // A completely fresh binding, add to the lists if it's valid.
2157 if ident.node.name != keywords::Invalid.name() {
2158 bindings.insert(ident.node, outer_pat_id);
2159 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2164 PathResolution::new(def)
2167 fn resolve_pattern(&mut self,
2169 pat_src: PatternSource,
2170 // Maps idents to the node ID for the
2171 // outermost pattern that binds them.
2172 bindings: &mut FxHashMap<Ident, NodeId>) {
2173 // Visit all direct subpatterns of this pattern.
2174 let outer_pat_id = pat.id;
2175 pat.walk(&mut |pat| {
2177 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2178 // First try to resolve the identifier as some existing
2179 // entity, then fall back to a fresh binding.
2180 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2182 .and_then(LexicalScopeBinding::item);
2183 let resolution = binding.map(NameBinding::def).and_then(|def| {
2184 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2185 bmode != BindingMode::ByValue(Mutability::Immutable);
2187 Def::StructCtor(_, CtorKind::Const) |
2188 Def::VariantCtor(_, CtorKind::Const) |
2189 Def::Const(..) if !always_binding => {
2190 // A unit struct/variant or constant pattern.
2191 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2192 Some(PathResolution::new(def))
2194 Def::StructCtor(..) | Def::VariantCtor(..) |
2195 Def::Const(..) | Def::Static(..) => {
2196 // A fresh binding that shadows something unacceptable.
2200 ResolutionError::BindingShadowsSomethingUnacceptable(
2201 pat_src.descr(), ident.node.name, binding.unwrap())
2205 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2206 // These entities are explicitly allowed
2207 // to be shadowed by fresh bindings.
2211 span_bug!(ident.span, "unexpected definition for an \
2212 identifier in pattern: {:?}", def);
2215 }).unwrap_or_else(|| {
2216 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2219 self.record_def(pat.id, resolution);
2222 PatKind::TupleStruct(ref path, ..) => {
2223 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2226 PatKind::Path(ref qself, ref path) => {
2227 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2230 PatKind::Struct(ref path, ..) => {
2231 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2239 visit::walk_pat(self, pat);
2242 // High-level and context dependent path resolution routine.
2243 // Resolves the path and records the resolution into definition map.
2244 // If resolution fails tries several techniques to find likely
2245 // resolution candidates, suggest imports or other help, and report
2246 // errors in user friendly way.
2247 fn smart_resolve_path(&mut self,
2249 qself: Option<&QSelf>,
2253 let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
2254 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2255 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2258 fn smart_resolve_path_fragment(&mut self,
2260 qself: Option<&QSelf>,
2266 let ns = source.namespace();
2267 let is_expected = &|def| source.is_expected(def);
2268 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2270 // Base error is amended with one short label and possibly some longer helps/notes.
2271 let report_errors = |this: &mut Self, def: Option<Def>| {
2272 // Make the base error.
2273 let expected = source.descr_expected();
2274 let path_str = names_to_string(path);
2275 let code = source.error_code(def.is_some());
2276 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2277 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2278 format!("not a {}", expected), span)
2280 let item_str = path[path.len() - 1];
2281 let (mod_prefix, mod_str) = if path.len() == 1 {
2282 (format!(""), format!("this scope"))
2283 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2284 (format!(""), format!("the crate root"))
2286 let mod_path = &path[..path.len() - 1];
2287 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2288 PathResult::Module(module) => module.def(),
2290 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2291 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2293 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2294 format!("not found in {}", mod_str), ident_span)
2296 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2298 // Emit special messages for unresolved `Self` and `self`.
2299 if is_self_type(path, ns) {
2300 __diagnostic_used!(E0411);
2301 err.code("E0411".into());
2302 err.span_label(span, "`Self` is only available in traits and impls");
2305 if is_self_value(path, ns) {
2306 __diagnostic_used!(E0424);
2307 err.code("E0424".into());
2308 err.span_label(span, format!("`self` value is only available in \
2309 methods with `self` parameter"));
2313 // Try to lookup the name in more relaxed fashion for better error reporting.
2314 let ident = *path.last().unwrap();
2315 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2316 if !candidates.is_empty() {
2317 let mut module_span = this.current_module.span;
2318 module_span.hi = module_span.lo;
2319 // Report import candidates as help and proceed searching for labels.
2320 show_candidates(&mut err, module_span, &candidates, def.is_some());
2321 } else if is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2322 let enum_candidates =
2323 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
2324 let mut enum_candidates = enum_candidates.iter()
2325 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2326 enum_candidates.sort();
2327 for (sp, variant_path, enum_path) in enum_candidates {
2328 let msg = format!("there is an enum variant `{}`, did you mean to use `{}`?",
2334 err.span_help(sp, &msg);
2338 if path.len() == 1 && this.self_type_is_available(span) {
2339 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
2340 let self_is_available = this.self_value_is_available(path[0].ctxt, span);
2342 AssocSuggestion::Field => {
2343 err.span_label(span, format!("did you mean `self.{}`?", path_str));
2344 if !self_is_available {
2345 err.span_label(span, format!("`self` value is only available in \
2346 methods with `self` parameter"));
2349 AssocSuggestion::MethodWithSelf if self_is_available => {
2350 err.span_label(span, format!("did you mean `self.{}(...)`?",
2353 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2354 err.span_label(span, format!("did you mean `Self::{}`?", path_str));
2361 let mut levenshtein_worked = false;
2364 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2365 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2366 levenshtein_worked = true;
2369 // Try context dependent help if relaxed lookup didn't work.
2370 if let Some(def) = def {
2371 match (def, source) {
2372 (Def::Macro(..), _) => {
2373 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2376 (Def::TyAlias(..), PathSource::Trait) => {
2377 err.span_label(span, "type aliases cannot be used for traits");
2380 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2381 ExprKind::Field(_, ident) => {
2382 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2383 path_str, ident.node));
2386 ExprKind::MethodCall(ident, ..) => {
2387 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2388 path_str, ident.node));
2393 _ if ns == ValueNS && is_struct_like(def) => {
2394 if let Def::Struct(def_id) = def {
2395 if let Some((ctor_def, ctor_vis))
2396 = this.struct_constructors.get(&def_id).cloned() {
2397 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2398 err.span_label(span, format!("constructor is not visible \
2399 here due to private fields"));
2403 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2412 if !levenshtein_worked {
2413 err.span_label(base_span, fallback_label);
2417 let report_errors = |this: &mut Self, def: Option<Def>| {
2418 report_errors(this, def).emit();
2419 err_path_resolution()
2422 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2423 source.defer_to_typeck(),
2424 source.global_by_default()) {
2425 Some(resolution) if resolution.unresolved_segments() == 0 => {
2426 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2429 // Add a temporary hack to smooth the transition to new struct ctor
2430 // visibility rules. See #38932 for more details.
2432 if let Def::Struct(def_id) = resolution.base_def() {
2433 if let Some((ctor_def, ctor_vis))
2434 = self.struct_constructors.get(&def_id).cloned() {
2435 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2436 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2437 self.session.add_lint(lint, id, span,
2438 "private struct constructors are not usable through \
2439 reexports in outer modules".to_string());
2440 res = Some(PathResolution::new(ctor_def));
2445 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2448 Some(resolution) if source.defer_to_typeck() => {
2449 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2450 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2451 // it needs to be added to the trait map.
2453 let item_name = *path.last().unwrap();
2454 let traits = self.get_traits_containing_item(item_name, ns);
2455 self.trait_map.insert(id, traits);
2459 _ => report_errors(self, None)
2462 if let PathSource::TraitItem(..) = source {} else {
2463 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2464 self.record_def(id, resolution);
2469 fn self_type_is_available(&mut self, span: Span) -> bool {
2470 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2471 TypeNS, false, span);
2472 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2475 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2476 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2477 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2478 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2481 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2482 fn resolve_qpath_anywhere(&mut self,
2484 qself: Option<&QSelf>,
2486 primary_ns: Namespace,
2488 defer_to_typeck: bool,
2489 global_by_default: bool)
2490 -> Option<PathResolution> {
2491 let mut fin_res = None;
2492 // FIXME: can't resolve paths in macro namespace yet, macros are
2493 // processed by the little special hack below.
2494 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2495 if i == 0 || ns != primary_ns {
2496 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2497 // If defer_to_typeck, then resolution > no resolution,
2498 // otherwise full resolution > partial resolution > no resolution.
2499 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2501 res => if fin_res.is_none() { fin_res = res },
2505 let is_global = self.global_macros.get(&path[0].name).cloned()
2506 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2507 if primary_ns != MacroNS && (is_global || self.macro_names.contains(&path[0].name)) {
2508 // Return some dummy definition, it's enough for error reporting.
2510 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2516 /// Handles paths that may refer to associated items.
2517 fn resolve_qpath(&mut self,
2519 qself: Option<&QSelf>,
2523 global_by_default: bool)
2524 -> Option<PathResolution> {
2525 if let Some(qself) = qself {
2526 if qself.position == 0 {
2527 // FIXME: Create some fake resolution that can't possibly be a type.
2528 return Some(PathResolution::with_unresolved_segments(
2529 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2532 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2533 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2534 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2535 span, span, PathSource::TraitItem(ns));
2536 return Some(PathResolution::with_unresolved_segments(
2537 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2541 let result = match self.resolve_path(&path, Some(ns), true, span) {
2542 PathResult::NonModule(path_res) => path_res,
2543 PathResult::Module(module) if !module.is_normal() => {
2544 PathResolution::new(module.def().unwrap())
2546 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2547 // don't report an error right away, but try to fallback to a primitive type.
2548 // So, we are still able to successfully resolve something like
2550 // use std::u8; // bring module u8 in scope
2551 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2552 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2553 // // not to non-existent std::u8::max_value
2556 // Such behavior is required for backward compatibility.
2557 // The same fallback is used when `a` resolves to nothing.
2558 PathResult::Module(..) | PathResult::Failed(..)
2559 if (ns == TypeNS || path.len() > 1) &&
2560 self.primitive_type_table.primitive_types.contains_key(&path[0].name) => {
2561 let prim = self.primitive_type_table.primitive_types[&path[0].name];
2563 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2564 if !self.session.features.borrow().i128_type {
2565 emit_feature_err(&self.session.parse_sess,
2566 "i128_type", span, GateIssue::Language,
2567 "128-bit type is unstable");
2573 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2575 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2576 PathResult::Failed(msg, false) => {
2577 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2578 err_path_resolution()
2580 PathResult::Failed(..) => return None,
2581 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2584 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2585 path[0].name != keywords::CrateRoot.name() && path[0].name != "$crate" {
2586 let unqualified_result = {
2587 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2588 PathResult::NonModule(path_res) => path_res.base_def(),
2589 PathResult::Module(module) => module.def().unwrap(),
2590 _ => return Some(result),
2593 if result.base_def() == unqualified_result {
2594 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2595 self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
2602 fn resolve_path(&mut self,
2604 opt_ns: Option<Namespace>, // `None` indicates a module path
2608 let mut module = None;
2609 let mut allow_super = true;
2611 for (i, &ident) in path.iter().enumerate() {
2612 let is_last = i == path.len() - 1;
2613 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2615 if i == 0 && ns == TypeNS && ident.name == keywords::SelfValue.name() {
2616 module = Some(self.module_map[&self.current_module.normal_ancestor_id]);
2618 } else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() {
2619 let current_module = if i == 0 { self.current_module } else { module.unwrap() };
2620 let self_module = self.module_map[¤t_module.normal_ancestor_id];
2621 if let Some(parent) = self_module.parent {
2622 module = Some(self.module_map[&parent.normal_ancestor_id]);
2625 let msg = "There are too many initial `super`s.".to_string();
2626 return PathResult::Failed(msg, false);
2629 allow_super = false;
2631 if i == 0 && ns == TypeNS && ident.name == keywords::CrateRoot.name() {
2632 module = Some(self.graph_root);
2634 } else if i == 0 && ns == TypeNS && ident.name == "$crate" {
2635 module = Some(self.resolve_crate_var(ident.ctxt, path_span));
2639 let binding = if let Some(module) = module {
2640 self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
2641 } else if opt_ns == Some(MacroNS) {
2642 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
2643 .map(MacroBinding::binding)
2645 match self.resolve_ident_in_lexical_scope(ident, ns, record_used, path_span) {
2646 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2647 Some(LexicalScopeBinding::Def(def))
2648 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2649 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2653 _ => Err(if record_used { Determined } else { Undetermined }),
2659 let def = binding.def();
2660 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2661 if let Some(next_module) = binding.module() {
2662 module = Some(next_module);
2663 } else if def == Def::Err {
2664 return PathResult::NonModule(err_path_resolution());
2665 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2666 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2667 def, path.len() - i - 1
2670 return PathResult::Failed(format!("Not a module `{}`", ident), is_last);
2673 Err(Undetermined) => return PathResult::Indeterminate,
2674 Err(Determined) => {
2675 if let Some(module) = module {
2676 if opt_ns.is_some() && !module.is_normal() {
2677 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2678 module.def().unwrap(), path.len() - i
2682 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2683 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2684 let mut candidates =
2685 self.lookup_import_candidates(ident.name, TypeNS, is_mod);
2686 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2687 if let Some(candidate) = candidates.get(0) {
2688 format!("Did you mean `{}`?", candidate.path)
2690 format!("Maybe a missing `extern crate {};`?", ident)
2693 format!("Use of undeclared type or module `{}`", ident)
2695 format!("Could not find `{}` in `{}`", ident, path[i - 1])
2697 return PathResult::Failed(msg, is_last);
2702 PathResult::Module(module.unwrap_or(self.graph_root))
2705 // Resolve a local definition, potentially adjusting for closures.
2706 fn adjust_local_def(&mut self,
2711 span: Span) -> Def {
2712 let ribs = &self.ribs[ns][rib_index + 1..];
2714 // An invalid forward use of a type parameter from a previous default.
2715 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2717 resolve_error(self, span,
2718 ResolutionError::ForwardDeclaredTyParam);
2720 assert_eq!(def, Def::Err);
2726 span_bug!(span, "unexpected {:?} in bindings", def)
2728 Def::Local(def_id) => {
2731 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2732 ForwardTyParamBanRibKind => {
2733 // Nothing to do. Continue.
2735 ClosureRibKind(function_id) => {
2737 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2739 let seen = self.freevars_seen
2741 .or_insert_with(|| NodeMap());
2742 if let Some(&index) = seen.get(&node_id) {
2743 def = Def::Upvar(def_id, index, function_id);
2746 let vec = self.freevars
2748 .or_insert_with(|| vec![]);
2749 let depth = vec.len();
2750 def = Def::Upvar(def_id, depth, function_id);
2757 seen.insert(node_id, depth);
2760 ItemRibKind | MethodRibKind(_) => {
2761 // This was an attempt to access an upvar inside a
2762 // named function item. This is not allowed, so we
2765 resolve_error(self, span,
2766 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2770 ConstantItemRibKind => {
2771 // Still doesn't deal with upvars
2773 resolve_error(self, span,
2774 ResolutionError::AttemptToUseNonConstantValueInConstant);
2781 Def::TyParam(..) | Def::SelfTy(..) => {
2784 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2785 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
2786 ConstantItemRibKind => {
2787 // Nothing to do. Continue.
2790 // This was an attempt to use a type parameter outside
2793 resolve_error(self, span,
2794 ResolutionError::TypeParametersFromOuterFunction);
2806 // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
2807 // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
2808 // FIXME #34673: This needs testing.
2809 pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
2810 where F: FnOnce(&mut Resolver<'a>) -> T,
2812 self.with_empty_ribs(|this| {
2813 this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2814 this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2819 fn with_empty_ribs<T, F>(&mut self, f: F) -> T
2820 where F: FnOnce(&mut Resolver<'a>) -> T,
2822 let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
2823 let label_ribs = replace(&mut self.label_ribs, Vec::new());
2825 let result = f(self);
2827 self.label_ribs = label_ribs;
2831 fn lookup_assoc_candidate<FilterFn>(&mut self,
2834 filter_fn: FilterFn)
2835 -> Option<AssocSuggestion>
2836 where FilterFn: Fn(Def) -> bool
2838 fn extract_node_id(t: &Ty) -> Option<NodeId> {
2840 TyKind::Path(None, _) => Some(t.id),
2841 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
2842 // This doesn't handle the remaining `Ty` variants as they are not
2843 // that commonly the self_type, it might be interesting to provide
2844 // support for those in future.
2849 // Fields are generally expected in the same contexts as locals.
2850 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
2851 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
2852 // Look for a field with the same name in the current self_type.
2853 if let Some(resolution) = self.def_map.get(&node_id) {
2854 match resolution.base_def() {
2855 Def::Struct(did) | Def::Union(did)
2856 if resolution.unresolved_segments() == 0 => {
2857 if let Some(field_names) = self.field_names.get(&did) {
2858 if field_names.iter().any(|&field_name| ident.name == field_name) {
2859 return Some(AssocSuggestion::Field);
2869 // Look for associated items in the current trait.
2870 if let Some((module, _)) = self.current_trait_ref {
2871 if let Ok(binding) =
2872 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
2873 let def = binding.def();
2875 return Some(if self.has_self.contains(&def.def_id()) {
2876 AssocSuggestion::MethodWithSelf
2878 AssocSuggestion::AssocItem
2887 fn lookup_typo_candidate<FilterFn>(&mut self,
2890 filter_fn: FilterFn,
2893 where FilterFn: Fn(Def) -> bool
2895 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
2896 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
2897 if let Some(binding) = resolution.borrow().binding {
2898 if filter_fn(binding.def()) {
2899 names.push(ident.name);
2905 let mut names = Vec::new();
2906 if path.len() == 1 {
2907 // Search in lexical scope.
2908 // Walk backwards up the ribs in scope and collect candidates.
2909 for rib in self.ribs[ns].iter().rev() {
2910 // Locals and type parameters
2911 for (ident, def) in &rib.bindings {
2912 if filter_fn(*def) {
2913 names.push(ident.name);
2917 if let ModuleRibKind(module) = rib.kind {
2918 // Items from this module
2919 add_module_candidates(module, &mut names);
2921 if let ModuleKind::Block(..) = module.kind {
2922 // We can see through blocks
2924 // Items from the prelude
2925 if let Some(prelude) = self.prelude {
2926 if !module.no_implicit_prelude {
2927 add_module_candidates(prelude, &mut names);
2934 // Add primitive types to the mix
2935 if filter_fn(Def::PrimTy(TyBool)) {
2936 for (name, _) in &self.primitive_type_table.primitive_types {
2941 // Search in module.
2942 let mod_path = &path[..path.len() - 1];
2943 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
2945 add_module_candidates(module, &mut names);
2949 let name = path[path.len() - 1].name;
2950 // Make sure error reporting is deterministic.
2951 names.sort_by_key(|name| name.as_str());
2952 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
2953 Some(found) if found != name => Some(found),
2958 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
2959 where F: FnOnce(&mut Resolver)
2961 if let Some(label) = label {
2962 let def = Def::Label(id);
2963 self.with_label_rib(|this| {
2964 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
2972 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
2973 self.with_resolved_label(label, id, |this| this.visit_block(block));
2976 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
2977 // First, record candidate traits for this expression if it could
2978 // result in the invocation of a method call.
2980 self.record_candidate_traits_for_expr_if_necessary(expr);
2982 // Next, resolve the node.
2984 ExprKind::Path(ref qself, ref path) => {
2985 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
2986 visit::walk_expr(self, expr);
2989 ExprKind::Struct(ref path, ..) => {
2990 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
2991 visit::walk_expr(self, expr);
2994 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
2995 match self.search_label(label.node) {
2997 self.record_def(expr.id, err_path_resolution());
3000 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
3002 Some(def @ Def::Label(_)) => {
3003 // Since this def is a label, it is never read.
3004 self.record_def(expr.id, PathResolution::new(def));
3007 span_bug!(expr.span, "label wasn't mapped to a label def!");
3011 // visit `break` argument if any
3012 visit::walk_expr(self, expr);
3015 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
3016 self.visit_expr(subexpression);
3018 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3019 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
3020 self.visit_block(if_block);
3021 self.ribs[ValueNS].pop();
3023 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3026 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3028 ExprKind::While(ref subexpression, ref block, label) => {
3029 self.with_resolved_label(label, expr.id, |this| {
3030 this.visit_expr(subexpression);
3031 this.visit_block(block);
3035 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3036 self.with_resolved_label(label, expr.id, |this| {
3037 this.visit_expr(subexpression);
3038 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3039 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3040 this.visit_block(block);
3041 this.ribs[ValueNS].pop();
3045 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3046 self.visit_expr(subexpression);
3047 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3048 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3050 self.resolve_labeled_block(label, expr.id, block);
3052 self.ribs[ValueNS].pop();
3055 // Equivalent to `visit::walk_expr` + passing some context to children.
3056 ExprKind::Field(ref subexpression, _) => {
3057 self.resolve_expr(subexpression, Some(expr));
3059 ExprKind::MethodCall(_, ref types, ref arguments) => {
3060 let mut arguments = arguments.iter();
3061 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3062 for argument in arguments {
3063 self.resolve_expr(argument, None);
3065 for ty in types.iter() {
3070 ExprKind::Repeat(ref element, ref count) => {
3071 self.visit_expr(element);
3072 self.with_constant_rib(|this| {
3073 this.visit_expr(count);
3076 ExprKind::Call(ref callee, ref arguments) => {
3077 self.resolve_expr(callee, Some(expr));
3078 for argument in arguments {
3079 self.resolve_expr(argument, None);
3084 visit::walk_expr(self, expr);
3089 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3091 ExprKind::Field(_, name) => {
3092 // FIXME(#6890): Even though you can't treat a method like a
3093 // field, we need to add any trait methods we find that match
3094 // the field name so that we can do some nice error reporting
3095 // later on in typeck.
3096 let traits = self.get_traits_containing_item(name.node, ValueNS);
3097 self.trait_map.insert(expr.id, traits);
3099 ExprKind::MethodCall(name, ..) => {
3100 debug!("(recording candidate traits for expr) recording traits for {}",
3102 let traits = self.get_traits_containing_item(name.node, ValueNS);
3103 self.trait_map.insert(expr.id, traits);
3111 fn get_traits_containing_item(&mut self, ident: Ident, ns: Namespace) -> Vec<TraitCandidate> {
3112 debug!("(getting traits containing item) looking for '{}'", ident.name);
3114 let mut found_traits = Vec::new();
3115 // Look for the current trait.
3116 if let Some((module, _)) = self.current_trait_ref {
3117 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3118 let def_id = module.def_id().unwrap();
3119 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3123 let mut search_module = self.current_module;
3125 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3126 match search_module.kind {
3127 ModuleKind::Block(..) => search_module = search_module.parent.unwrap(),
3132 if let Some(prelude) = self.prelude {
3133 if !search_module.no_implicit_prelude {
3134 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3141 fn get_traits_in_module_containing_item(&mut self,
3145 found_traits: &mut Vec<TraitCandidate>) {
3146 let mut traits = module.traits.borrow_mut();
3147 if traits.is_none() {
3148 let mut collected_traits = Vec::new();
3149 module.for_each_child(|name, ns, binding| {
3150 if ns != TypeNS { return }
3151 if let Def::Trait(_) = binding.def() {
3152 collected_traits.push((name, binding));
3155 *traits = Some(collected_traits.into_boxed_slice());
3158 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3159 let module = binding.module().unwrap();
3160 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3161 let import_id = match binding.kind {
3162 NameBindingKind::Import { directive, .. } => {
3163 self.maybe_unused_trait_imports.insert(directive.id);
3164 self.add_to_glob_map(directive.id, trait_name);
3169 let trait_def_id = module.def_id().unwrap();
3170 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3175 /// When name resolution fails, this method can be used to look up candidate
3176 /// entities with the expected name. It allows filtering them using the
3177 /// supplied predicate (which should be used to only accept the types of
3178 /// definitions expected e.g. traits). The lookup spans across all crates.
3180 /// NOTE: The method does not look into imports, but this is not a problem,
3181 /// since we report the definitions (thus, the de-aliased imports).
3182 fn lookup_import_candidates<FilterFn>(&mut self,
3184 namespace: Namespace,
3185 filter_fn: FilterFn)
3186 -> Vec<ImportSuggestion>
3187 where FilterFn: Fn(Def) -> bool
3189 let mut candidates = Vec::new();
3190 let mut worklist = Vec::new();
3191 let mut seen_modules = FxHashSet();
3192 worklist.push((self.graph_root, Vec::new(), false));
3194 while let Some((in_module,
3196 in_module_is_extern)) = worklist.pop() {
3197 self.populate_module_if_necessary(in_module);
3199 in_module.for_each_child(|ident, ns, name_binding| {
3201 // avoid imports entirely
3202 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3203 // avoid non-importable candidates as well
3204 if !name_binding.is_importable() { return; }
3206 // collect results based on the filter function
3207 if ident.name == lookup_name && ns == namespace {
3208 if filter_fn(name_binding.def()) {
3210 let mut segms = path_segments.clone();
3211 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3213 span: name_binding.span,
3216 // the entity is accessible in the following cases:
3217 // 1. if it's defined in the same crate, it's always
3218 // accessible (since private entities can be made public)
3219 // 2. if it's defined in another crate, it's accessible
3220 // only if both the module is public and the entity is
3221 // declared as public (due to pruning, we don't explore
3222 // outside crate private modules => no need to check this)
3223 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3224 candidates.push(ImportSuggestion { path: path });
3229 // collect submodules to explore
3230 if let Some(module) = name_binding.module() {
3232 let mut path_segments = path_segments.clone();
3233 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3235 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3236 // add the module to the lookup
3237 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3238 if seen_modules.insert(module.def_id().unwrap()) {
3239 worklist.push((module, path_segments, is_extern));
3249 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3250 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3251 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3252 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3256 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3258 ast::Visibility::Public => ty::Visibility::Public,
3259 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3260 ast::Visibility::Inherited => {
3261 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3263 ast::Visibility::Restricted { ref path, id } => {
3264 let def = self.smart_resolve_path(id, None, path,
3265 PathSource::Visibility).base_def();
3266 if def == Def::Err {
3267 ty::Visibility::Public
3269 let vis = ty::Visibility::Restricted(def.def_id());
3270 if self.is_accessible(vis) {
3273 self.session.span_err(path.span, "visibilities can only be restricted \
3274 to ancestor modules");
3275 ty::Visibility::Public
3282 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3283 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3286 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3287 vis.is_accessible_from(module.normal_ancestor_id, self)
3290 fn report_errors(&mut self) {
3291 self.report_shadowing_errors();
3292 let mut reported_spans = FxHashSet();
3294 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3295 if !reported_spans.insert(span) { continue }
3296 let participle = |binding: &NameBinding| {
3297 if binding.is_import() { "imported" } else { "defined" }
3299 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3300 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3301 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3302 format!("consider adding an explicit import of `{}` to disambiguate", name)
3303 } else if let Def::Macro(..) = b1.def() {
3304 format!("macro-expanded {} do not shadow",
3305 if b1.is_import() { "macro imports" } else { "macros" })
3307 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3308 if b1.is_import() { "imports" } else { "items" })
3311 let id = match b2.kind {
3312 NameBindingKind::Import { directive, .. } => directive.id,
3313 _ => unreachable!(),
3315 let mut span = MultiSpan::from_span(span);
3316 span.push_span_label(b1.span, msg1);
3317 span.push_span_label(b2.span, msg2);
3318 let msg = format!("`{}` is ambiguous", name);
3319 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3322 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3323 err.span_note(b1.span, &msg1);
3325 Def::Macro(..) if b2.span == DUMMY_SP =>
3326 err.note(&format!("`{}` is also a builtin macro", name)),
3327 _ => err.span_note(b2.span, &msg2),
3329 err.note(¬e).emit();
3333 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3334 if !reported_spans.insert(span) { continue }
3335 if binding.is_extern_crate() {
3336 // Warn when using an inaccessible extern crate.
3337 let node_id = match binding.kind {
3338 NameBindingKind::Import { directive, .. } => directive.id,
3339 _ => unreachable!(),
3341 let msg = format!("extern crate `{}` is private", name);
3342 self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
3344 let def = binding.def();
3345 self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
3350 fn report_shadowing_errors(&mut self) {
3351 for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3352 self.resolve_legacy_scope(scope, name, true);
3355 let mut reported_errors = FxHashSet();
3356 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3357 if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() &&
3358 reported_errors.insert((binding.name, binding.span)) {
3359 let msg = format!("`{}` is already in scope", binding.name);
3360 self.session.struct_span_err(binding.span, &msg)
3361 .note("macro-expanded `macro_rules!`s may not shadow \
3362 existing macros (see RFC 1560)")
3368 fn report_conflict(&mut self,
3372 binding: &NameBinding,
3373 old_binding: &NameBinding) {
3374 // Error on the second of two conflicting names
3375 if old_binding.span.lo > binding.span.lo {
3376 return self.report_conflict(parent, ident, ns, old_binding, binding);
3379 let container = match parent.kind {
3380 ModuleKind::Def(Def::Mod(_), _) => "module",
3381 ModuleKind::Def(Def::Trait(_), _) => "trait",
3382 ModuleKind::Block(..) => "block",
3386 let (participle, noun) = match old_binding.is_import() {
3387 true => ("imported", "import"),
3388 false => ("defined", "definition"),
3391 let (name, span) = (ident.name, binding.span);
3393 if let Some(s) = self.name_already_seen.get(&name) {
3400 let kind = match (ns, old_binding.module()) {
3401 (ValueNS, _) => "a value",
3402 (MacroNS, _) => "a macro",
3403 (TypeNS, _) if old_binding.is_extern_crate() => "an extern crate",
3404 (TypeNS, Some(module)) if module.is_normal() => "a module",
3405 (TypeNS, Some(module)) if module.is_trait() => "a trait",
3406 (TypeNS, _) => "a type",
3408 format!("{} named `{}` has already been {} in this {}",
3409 kind, name, participle, container)
3412 let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
3413 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3414 (true, _) | (_, true) => match binding.is_import() && old_binding.is_import() {
3415 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3416 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3418 _ => match (old_binding.is_import(), binding.is_import()) {
3419 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3420 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3421 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3425 err.span_label(span, format!("`{}` already {}", name, participle));
3426 if old_binding.span != syntax_pos::DUMMY_SP {
3427 err.span_label(old_binding.span, format!("previous {} of `{}` here", noun, name));
3430 self.name_already_seen.insert(name, span);
3433 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3434 let (id, span) = (directive.id, directive.span);
3435 let msg = "`self` no longer imports values".to_string();
3436 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3439 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3440 if self.proc_macro_enabled { return; }
3443 if attr.path.segments.len() > 1 {
3446 let ident = attr.path.segments[0].identifier;
3447 let result = self.resolve_lexical_macro_path_segment(ident,
3451 if let Ok(binding) = result {
3452 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3453 attr::mark_known(attr);
3455 let msg = "attribute procedural macros are experimental";
3456 let feature = "proc_macro";
3458 feature_err(&self.session.parse_sess, feature,
3459 attr.span, GateIssue::Language, msg)
3460 .span_note(binding.span(), "procedural macro imported here")
3468 fn is_struct_like(def: Def) -> bool {
3470 Def::VariantCtor(_, CtorKind::Fictive) => true,
3471 _ => PathSource::Struct.is_expected(def),
3475 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
3476 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
3479 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
3480 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
3483 fn names_to_string(idents: &[Ident]) -> String {
3484 let mut result = String::new();
3485 for (i, ident) in idents.iter().filter(|i| i.name != keywords::CrateRoot.name()).enumerate() {
3487 result.push_str("::");
3489 result.push_str(&ident.name.as_str());
3494 fn path_names_to_string(path: &Path) -> String {
3495 names_to_string(&path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>())
3498 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3499 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3500 let variant_path = &suggestion.path;
3501 let variant_path_string = path_names_to_string(variant_path);
3503 let path_len = suggestion.path.segments.len();
3504 let enum_path = ast::Path {
3505 span: suggestion.path.span,
3506 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3508 let enum_path_string = path_names_to_string(&enum_path);
3510 (suggestion.path.span, variant_path_string, enum_path_string)
3514 /// When an entity with a given name is not available in scope, we search for
3515 /// entities with that name in all crates. This method allows outputting the
3516 /// results of this search in a programmer-friendly way
3517 fn show_candidates(err: &mut DiagnosticBuilder,
3519 candidates: &[ImportSuggestion],
3522 // we want consistent results across executions, but candidates are produced
3523 // by iterating through a hash map, so make sure they are ordered:
3524 let mut path_strings: Vec<_> =
3525 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3526 path_strings.sort();
3528 let better = if better { "better " } else { "" };
3529 let msg_diff = match path_strings.len() {
3530 1 => " is found in another module, you can import it",
3531 _ => "s are found in other modules, you can import them",
3533 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3535 for candidate in &mut path_strings {
3536 *candidate = format!("use {};\n", candidate);
3539 err.span_suggestions(span, &msg, path_strings);
3542 /// A somewhat inefficient routine to obtain the name of a module.
3543 fn module_to_string(module: Module) -> String {
3544 let mut names = Vec::new();
3546 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3547 if let ModuleKind::Def(_, name) = module.kind {
3548 if let Some(parent) = module.parent {
3549 names.push(Ident::with_empty_ctxt(name));
3550 collect_mod(names, parent);
3553 // danger, shouldn't be ident?
3554 names.push(Ident::from_str("<opaque>"));
3555 collect_mod(names, module.parent.unwrap());
3558 collect_mod(&mut names, module);
3560 if names.is_empty() {
3561 return "???".to_string();
3563 names_to_string(&names.into_iter().rev().collect::<Vec<_>>())
3566 fn err_path_resolution() -> PathResolution {
3567 PathResolution::new(Def::Err)
3570 #[derive(PartialEq,Copy, Clone)]
3571 pub enum MakeGlobMap {
3576 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }