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,
1063 /// Interns the names of the primitive types.
1064 struct PrimitiveTypeTable {
1065 primitive_types: FxHashMap<Name, PrimTy>,
1068 impl PrimitiveTypeTable {
1069 fn new() -> PrimitiveTypeTable {
1070 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1072 table.intern("bool", TyBool);
1073 table.intern("char", TyChar);
1074 table.intern("f32", TyFloat(FloatTy::F32));
1075 table.intern("f64", TyFloat(FloatTy::F64));
1076 table.intern("isize", TyInt(IntTy::Is));
1077 table.intern("i8", TyInt(IntTy::I8));
1078 table.intern("i16", TyInt(IntTy::I16));
1079 table.intern("i32", TyInt(IntTy::I32));
1080 table.intern("i64", TyInt(IntTy::I64));
1081 table.intern("i128", TyInt(IntTy::I128));
1082 table.intern("str", TyStr);
1083 table.intern("usize", TyUint(UintTy::Us));
1084 table.intern("u8", TyUint(UintTy::U8));
1085 table.intern("u16", TyUint(UintTy::U16));
1086 table.intern("u32", TyUint(UintTy::U32));
1087 table.intern("u64", TyUint(UintTy::U64));
1088 table.intern("u128", TyUint(UintTy::U128));
1092 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1093 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1097 /// The main resolver class.
1098 pub struct Resolver<'a> {
1099 session: &'a Session,
1101 pub definitions: Definitions,
1103 graph_root: Module<'a>,
1105 prelude: Option<Module<'a>>,
1107 trait_item_map: FxHashMap<(DefId, Name, Namespace), (Def, bool /* has self */)>,
1109 // Names of fields of an item `DefId` accessible with dot syntax.
1110 // Used for hints during error reporting.
1111 field_names: FxHashMap<DefId, Vec<Name>>,
1113 // All imports known to succeed or fail.
1114 determined_imports: Vec<&'a ImportDirective<'a>>,
1116 // All non-determined imports.
1117 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1119 // The module that represents the current item scope.
1120 current_module: Module<'a>,
1122 // The current set of local scopes for types and values.
1123 // FIXME #4948: Reuse ribs to avoid allocation.
1124 ribs: PerNS<Vec<Rib<'a>>>,
1126 // The current set of local scopes, for labels.
1127 label_ribs: Vec<Rib<'a>>,
1129 // The trait that the current context can refer to.
1130 current_trait_ref: Option<(DefId, TraitRef)>,
1132 // The current self type if inside an impl (used for better errors).
1133 current_self_type: Option<Ty>,
1135 // The idents for the primitive types.
1136 primitive_type_table: PrimitiveTypeTable,
1139 pub freevars: FreevarMap,
1140 freevars_seen: NodeMap<NodeMap<usize>>,
1141 pub export_map: ExportMap,
1142 pub trait_map: TraitMap,
1144 // A map from nodes to anonymous modules.
1145 // Anonymous modules are pseudo-modules that are implicitly created around items
1146 // contained within blocks.
1148 // For example, if we have this:
1156 // There will be an anonymous module created around `g` with the ID of the
1157 // entry block for `f`.
1158 block_map: NodeMap<Module<'a>>,
1159 module_map: FxHashMap<DefId, Module<'a>>,
1160 extern_crate_roots: FxHashMap<(CrateNum, bool /* MacrosOnly? */), Module<'a>>,
1162 pub make_glob_map: bool,
1163 // Maps imports to the names of items actually imported (this actually maps
1164 // all imports, but only glob imports are actually interesting).
1165 pub glob_map: GlobMap,
1167 used_imports: FxHashSet<(NodeId, Namespace)>,
1168 pub maybe_unused_trait_imports: NodeSet,
1170 privacy_errors: Vec<PrivacyError<'a>>,
1171 ambiguity_errors: Vec<AmbiguityError<'a>>,
1172 gated_errors: FxHashSet<Span>,
1173 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1175 arenas: &'a ResolverArenas<'a>,
1176 dummy_binding: &'a NameBinding<'a>,
1177 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1179 crate_loader: &'a mut CrateLoader,
1180 macro_names: FxHashSet<Name>,
1181 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1182 lexical_macro_resolutions: Vec<(Name, &'a Cell<LegacyScope<'a>>)>,
1183 macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
1184 macro_defs: FxHashMap<Mark, DefId>,
1185 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1186 macro_exports: Vec<Export>,
1187 pub whitelisted_legacy_custom_derives: Vec<Name>,
1188 pub found_unresolved_macro: bool,
1190 // List of crate local macros that we need to warn about as being unused.
1191 // Right now this only includes macro_rules! macros.
1192 unused_macros: FxHashSet<DefId>,
1194 // Maps the `Mark` of an expansion to its containing module or block.
1195 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1197 // Avoid duplicated errors for "name already defined".
1198 name_already_seen: FxHashMap<Name, Span>,
1200 // If `#![feature(proc_macro)]` is set
1201 proc_macro_enabled: bool,
1203 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1204 warned_proc_macros: FxHashSet<Name>,
1206 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1208 // This table maps struct IDs into struct constructor IDs,
1209 // it's not used during normal resolution, only for better error reporting.
1210 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1213 pub struct ResolverArenas<'a> {
1214 modules: arena::TypedArena<ModuleData<'a>>,
1215 local_modules: RefCell<Vec<Module<'a>>>,
1216 name_bindings: arena::TypedArena<NameBinding<'a>>,
1217 import_directives: arena::TypedArena<ImportDirective<'a>>,
1218 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1219 invocation_data: arena::TypedArena<InvocationData<'a>>,
1220 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1223 impl<'a> ResolverArenas<'a> {
1224 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1225 let module = self.modules.alloc(module);
1226 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1227 self.local_modules.borrow_mut().push(module);
1231 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1232 self.local_modules.borrow()
1234 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1235 self.name_bindings.alloc(name_binding)
1237 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1238 -> &'a ImportDirective {
1239 self.import_directives.alloc(import_directive)
1241 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1242 self.name_resolutions.alloc(Default::default())
1244 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1245 -> &'a InvocationData<'a> {
1246 self.invocation_data.alloc(expansion_data)
1248 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1249 self.legacy_bindings.alloc(binding)
1253 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1254 fn parent(self, id: DefId) -> Option<DefId> {
1256 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1257 _ => self.session.cstore.def_key(id).parent,
1258 }.map(|index| DefId { index: index, ..id })
1262 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1263 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1264 let namespace = if is_value { ValueNS } else { TypeNS };
1265 let hir::Path { ref segments, span, ref mut def } = *path;
1266 let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect();
1267 match self.resolve_path(&path, Some(namespace), true, span) {
1268 PathResult::Module(module) => *def = module.def().unwrap(),
1269 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1270 *def = path_res.base_def(),
1271 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1272 PathResult::Failed(msg, _) => {
1273 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1277 PathResult::Indeterminate => unreachable!(),
1278 PathResult::Failed(msg, _) => {
1279 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1284 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1285 self.def_map.get(&id).cloned()
1288 fn definitions(&mut self) -> &mut Definitions {
1289 &mut self.definitions
1293 impl<'a> Resolver<'a> {
1294 pub fn new(session: &'a Session,
1297 make_glob_map: MakeGlobMap,
1298 crate_loader: &'a mut CrateLoader,
1299 arenas: &'a ResolverArenas<'a>)
1301 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1302 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1303 let graph_root = arenas.alloc_module(ModuleData {
1304 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1305 ..ModuleData::new(None, root_module_kind, root_def_id, krate.span)
1307 let mut module_map = FxHashMap();
1308 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1310 let mut definitions = Definitions::new();
1311 DefCollector::new(&mut definitions)
1312 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1314 let mut invocations = FxHashMap();
1315 invocations.insert(Mark::root(),
1316 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1318 let features = session.features.borrow();
1320 let mut macro_defs = FxHashMap();
1321 macro_defs.insert(Mark::root(), root_def_id);
1326 definitions: definitions,
1328 // The outermost module has def ID 0; this is not reflected in the
1330 graph_root: graph_root,
1333 trait_item_map: FxHashMap(),
1334 field_names: FxHashMap(),
1336 determined_imports: Vec::new(),
1337 indeterminate_imports: Vec::new(),
1339 current_module: graph_root,
1341 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1342 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1343 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1345 label_ribs: Vec::new(),
1347 current_trait_ref: None,
1348 current_self_type: None,
1350 primitive_type_table: PrimitiveTypeTable::new(),
1353 freevars: NodeMap(),
1354 freevars_seen: NodeMap(),
1355 export_map: NodeMap(),
1356 trait_map: NodeMap(),
1357 module_map: module_map,
1358 block_map: NodeMap(),
1359 extern_crate_roots: FxHashMap(),
1361 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1362 glob_map: NodeMap(),
1364 used_imports: FxHashSet(),
1365 maybe_unused_trait_imports: NodeSet(),
1367 privacy_errors: Vec::new(),
1368 ambiguity_errors: Vec::new(),
1369 gated_errors: FxHashSet(),
1370 disallowed_shadowing: Vec::new(),
1373 dummy_binding: arenas.alloc_name_binding(NameBinding {
1374 kind: NameBindingKind::Def(Def::Err),
1375 expansion: Mark::root(),
1377 vis: ty::Visibility::Public,
1380 // `#![feature(proc_macro)]` implies `#[feature(extern_macros)]`
1381 use_extern_macros: features.use_extern_macros || features.proc_macro,
1383 crate_loader: crate_loader,
1384 macro_names: FxHashSet(),
1385 global_macros: FxHashMap(),
1386 lexical_macro_resolutions: Vec::new(),
1387 macro_map: FxHashMap(),
1388 macro_exports: Vec::new(),
1389 invocations: invocations,
1390 macro_defs: macro_defs,
1391 local_macro_def_scopes: FxHashMap(),
1392 name_already_seen: FxHashMap(),
1393 whitelisted_legacy_custom_derives: Vec::new(),
1394 proc_macro_enabled: features.proc_macro,
1395 warned_proc_macros: FxHashSet(),
1396 potentially_unused_imports: Vec::new(),
1397 struct_constructors: DefIdMap(),
1398 found_unresolved_macro: false,
1399 unused_macros: FxHashSet(),
1403 pub fn arenas() -> ResolverArenas<'a> {
1405 modules: arena::TypedArena::new(),
1406 local_modules: RefCell::new(Vec::new()),
1407 name_bindings: arena::TypedArena::new(),
1408 import_directives: arena::TypedArena::new(),
1409 name_resolutions: arena::TypedArena::new(),
1410 invocation_data: arena::TypedArena::new(),
1411 legacy_bindings: arena::TypedArena::new(),
1415 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1417 type_ns: f(self, TypeNS),
1418 value_ns: f(self, ValueNS),
1419 macro_ns: match self.use_extern_macros {
1420 true => Some(f(self, MacroNS)),
1426 /// Entry point to crate resolution.
1427 pub fn resolve_crate(&mut self, krate: &Crate) {
1428 ImportResolver { resolver: self }.finalize_imports();
1429 self.current_module = self.graph_root;
1430 self.finalize_current_module_macro_resolutions();
1431 visit::walk_crate(self, krate);
1433 check_unused::check_crate(self, krate);
1434 self.report_errors();
1435 self.crate_loader.postprocess(krate);
1442 normal_ancestor_id: DefId,
1445 self.arenas.alloc_module(ModuleData::new(Some(parent), kind, normal_ancestor_id, span))
1448 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1449 -> bool /* true if an error was reported */ {
1450 match binding.kind {
1451 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1454 directive.used.set(true);
1455 if legacy_self_import {
1456 self.warn_legacy_self_import(directive);
1459 self.used_imports.insert((directive.id, ns));
1460 self.add_to_glob_map(directive.id, ident);
1461 self.record_use(ident, ns, binding, span)
1463 NameBindingKind::Import { .. } => false,
1464 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1465 self.ambiguity_errors.push(AmbiguityError {
1466 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
1469 self.record_use(ident, ns, b1, span);
1477 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1478 if self.make_glob_map {
1479 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1483 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1484 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1485 /// `ident` in the first scope that defines it (or None if no scopes define it).
1487 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1488 /// the items are defined in the block. For example,
1491 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1494 /// g(); // This resolves to the local variable `g` since it shadows the item.
1498 /// Invariant: This must only be called during main resolution, not during
1499 /// import resolution.
1500 fn resolve_ident_in_lexical_scope(&mut self,
1505 -> Option<LexicalScopeBinding<'a>> {
1507 ident = ident.unhygienize();
1510 // Walk backwards up the ribs in scope.
1511 for i in (0 .. self.ribs[ns].len()).rev() {
1512 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1513 // The ident resolves to a type parameter or local variable.
1514 return Some(LexicalScopeBinding::Def(
1515 self.adjust_local_def(ns, i, def, record_used, path_span)
1519 if let ModuleRibKind(module) = self.ribs[ns][i].kind {
1520 let item = self.resolve_ident_in_module(module, ident, ns, false,
1521 record_used, path_span);
1522 if let Ok(binding) = item {
1523 // The ident resolves to an item.
1524 return Some(LexicalScopeBinding::Item(binding));
1527 if let ModuleKind::Block(..) = module.kind { // We can see through blocks
1528 } else if !module.no_implicit_prelude {
1529 return self.prelude.and_then(|prelude| {
1530 self.resolve_ident_in_module(prelude, ident, ns, false,
1531 false, path_span).ok()
1532 }).map(LexicalScopeBinding::Item)
1538 if let MacroDefinition(def) = self.ribs[ns][i].kind {
1539 // If an invocation of this macro created `ident`, give up on `ident`
1540 // and switch to `ident`'s source from the macro definition.
1541 let ctxt_data = ident.ctxt.data();
1542 if def == self.macro_defs[&ctxt_data.outer_mark] {
1543 ident.ctxt = ctxt_data.prev_ctxt;
1551 fn resolve_crate_var(&mut self, crate_var_ctxt: SyntaxContext, span: Span) -> Module<'a> {
1552 let mut ctxt_data = crate_var_ctxt.data();
1553 while ctxt_data.prev_ctxt != SyntaxContext::empty() {
1554 ctxt_data = ctxt_data.prev_ctxt.data();
1556 let module = self.macro_def_scope(ctxt_data.outer_mark, span);
1557 if module.is_local() { self.graph_root } else { module }
1562 // We maintain a list of value ribs and type ribs.
1564 // Simultaneously, we keep track of the current position in the module
1565 // graph in the `current_module` pointer. When we go to resolve a name in
1566 // the value or type namespaces, we first look through all the ribs and
1567 // then query the module graph. When we resolve a name in the module
1568 // namespace, we can skip all the ribs (since nested modules are not
1569 // allowed within blocks in Rust) and jump straight to the current module
1572 // Named implementations are handled separately. When we find a method
1573 // call, we consult the module node to find all of the implementations in
1574 // scope. This information is lazily cached in the module node. We then
1575 // generate a fake "implementation scope" containing all the
1576 // implementations thus found, for compatibility with old resolve pass.
1578 fn with_scope<F>(&mut self, id: NodeId, f: F)
1579 where F: FnOnce(&mut Resolver)
1581 let id = self.definitions.local_def_id(id);
1582 let module = self.module_map.get(&id).cloned(); // clones a reference
1583 if let Some(module) = module {
1584 // Move down in the graph.
1585 let orig_module = replace(&mut self.current_module, module);
1586 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1587 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1589 self.finalize_current_module_macro_resolutions();
1592 self.current_module = orig_module;
1593 self.ribs[ValueNS].pop();
1594 self.ribs[TypeNS].pop();
1600 /// Searches the current set of local scopes for labels.
1601 /// Stops after meeting a closure.
1602 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1603 for rib in self.label_ribs.iter().rev() {
1608 MacroDefinition(def) => {
1609 // If an invocation of this macro created `ident`, give up on `ident`
1610 // and switch to `ident`'s source from the macro definition.
1611 let ctxt_data = ident.ctxt.data();
1612 if def == self.macro_defs[&ctxt_data.outer_mark] {
1613 ident.ctxt = ctxt_data.prev_ctxt;
1617 // Do not resolve labels across function boundary
1621 let result = rib.bindings.get(&ident).cloned();
1622 if result.is_some() {
1629 fn resolve_item(&mut self, item: &Item) {
1630 let name = item.ident.name;
1632 debug!("(resolving item) resolving {}", name);
1634 self.check_proc_macro_attrs(&item.attrs);
1637 ItemKind::Enum(_, ref generics) |
1638 ItemKind::Ty(_, ref generics) |
1639 ItemKind::Struct(_, ref generics) |
1640 ItemKind::Union(_, ref generics) |
1641 ItemKind::Fn(.., ref generics, _) => {
1642 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1643 |this| visit::walk_item(this, item));
1646 ItemKind::DefaultImpl(_, ref trait_ref) => {
1647 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1648 // Resolve type arguments in trait path
1649 visit::walk_trait_ref(this, trait_ref);
1652 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1653 self.resolve_implementation(generics,
1659 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1660 // Create a new rib for the trait-wide type parameters.
1661 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1662 let local_def_id = this.definitions.local_def_id(item.id);
1663 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1664 this.visit_generics(generics);
1665 walk_list!(this, visit_ty_param_bound, bounds);
1667 for trait_item in trait_items {
1668 this.check_proc_macro_attrs(&trait_item.attrs);
1670 match trait_item.node {
1671 TraitItemKind::Const(ref ty, ref default) => {
1674 // Only impose the restrictions of
1675 // ConstRibKind for an actual constant
1676 // expression in a provided default.
1677 if let Some(ref expr) = *default{
1678 this.with_constant_rib(|this| {
1679 this.visit_expr(expr);
1683 TraitItemKind::Method(ref sig, _) => {
1684 let type_parameters =
1685 HasTypeParameters(&sig.generics,
1686 MethodRibKind(!sig.decl.has_self()));
1687 this.with_type_parameter_rib(type_parameters, |this| {
1688 visit::walk_trait_item(this, trait_item)
1691 TraitItemKind::Type(..) => {
1692 this.with_type_parameter_rib(NoTypeParameters, |this| {
1693 visit::walk_trait_item(this, trait_item)
1696 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1703 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1704 self.with_scope(item.id, |this| {
1705 visit::walk_item(this, item);
1709 ItemKind::Static(ref ty, _, ref expr) |
1710 ItemKind::Const(ref ty, ref expr) => {
1711 self.with_item_rib(|this| {
1713 this.with_constant_rib(|this| {
1714 this.visit_expr(expr);
1719 ItemKind::Use(ref view_path) => {
1720 match view_path.node {
1721 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1722 // Resolve prefix of an import with empty braces (issue #28388).
1723 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1729 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1730 // do nothing, these are just around to be encoded
1733 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1737 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1738 where F: FnOnce(&mut Resolver)
1740 match type_parameters {
1741 HasTypeParameters(generics, rib_kind) => {
1742 let mut function_type_rib = Rib::new(rib_kind);
1743 let mut seen_bindings = FxHashMap();
1744 for type_parameter in &generics.ty_params {
1745 let name = type_parameter.ident.name;
1746 debug!("with_type_parameter_rib: {}", type_parameter.id);
1748 if seen_bindings.contains_key(&name) {
1749 let span = seen_bindings.get(&name).unwrap();
1751 type_parameter.span,
1752 ResolutionError::NameAlreadyUsedInTypeParameterList(name,
1755 seen_bindings.entry(name).or_insert(type_parameter.span);
1757 // plain insert (no renaming)
1758 let def_id = self.definitions.local_def_id(type_parameter.id);
1759 let def = Def::TyParam(def_id);
1760 function_type_rib.bindings.insert(Ident::with_empty_ctxt(name), def);
1761 self.record_def(type_parameter.id, PathResolution::new(def));
1763 self.ribs[TypeNS].push(function_type_rib);
1766 NoTypeParameters => {
1773 if let HasTypeParameters(..) = type_parameters {
1774 self.ribs[TypeNS].pop();
1778 fn with_label_rib<F>(&mut self, f: F)
1779 where F: FnOnce(&mut Resolver)
1781 self.label_ribs.push(Rib::new(NormalRibKind));
1783 self.label_ribs.pop();
1786 fn with_item_rib<F>(&mut self, f: F)
1787 where F: FnOnce(&mut Resolver)
1789 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
1790 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
1792 self.ribs[TypeNS].pop();
1793 self.ribs[ValueNS].pop();
1796 fn with_constant_rib<F>(&mut self, f: F)
1797 where F: FnOnce(&mut Resolver)
1799 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1801 self.ribs[ValueNS].pop();
1804 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1805 where F: FnOnce(&mut Resolver) -> T
1807 // Handle nested impls (inside fn bodies)
1808 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1809 let result = f(self);
1810 self.current_self_type = previous_value;
1814 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1815 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1817 let mut new_val = None;
1818 let mut new_id = None;
1819 if let Some(trait_ref) = opt_trait_ref {
1820 let def = self.smart_resolve_path(trait_ref.ref_id, None,
1821 &trait_ref.path, PathSource::Trait).base_def();
1822 if def != Def::Err {
1823 new_val = Some((def.def_id(), trait_ref.clone()));
1824 new_id = Some(def.def_id());
1827 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1828 let result = f(self, new_id);
1829 self.current_trait_ref = original_trait_ref;
1833 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1834 where F: FnOnce(&mut Resolver)
1836 let mut self_type_rib = Rib::new(NormalRibKind);
1838 // plain insert (no renaming, types are not currently hygienic....)
1839 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
1840 self.ribs[TypeNS].push(self_type_rib);
1842 self.ribs[TypeNS].pop();
1845 fn resolve_implementation(&mut self,
1846 generics: &Generics,
1847 opt_trait_reference: &Option<TraitRef>,
1850 impl_items: &[ImplItem]) {
1851 // If applicable, create a rib for the type parameters.
1852 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1853 // Dummy self type for better errors if `Self` is used in the trait path.
1854 this.with_self_rib(Def::SelfTy(None, None), |this| {
1855 // Resolve the trait reference, if necessary.
1856 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1857 let item_def_id = this.definitions.local_def_id(item_id);
1858 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
1859 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1860 // Resolve type arguments in trait path
1861 visit::walk_trait_ref(this, trait_ref);
1863 // Resolve the self type.
1864 this.visit_ty(self_type);
1865 // Resolve the type parameters.
1866 this.visit_generics(generics);
1867 this.with_current_self_type(self_type, |this| {
1868 for impl_item in impl_items {
1869 this.check_proc_macro_attrs(&impl_item.attrs);
1870 this.resolve_visibility(&impl_item.vis);
1871 match impl_item.node {
1872 ImplItemKind::Const(..) => {
1873 // If this is a trait impl, ensure the const
1875 this.check_trait_item(impl_item.ident.name,
1878 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
1879 visit::walk_impl_item(this, impl_item);
1881 ImplItemKind::Method(ref sig, _) => {
1882 // If this is a trait impl, ensure the method
1884 this.check_trait_item(impl_item.ident.name,
1887 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
1889 // We also need a new scope for the method-
1890 // specific type parameters.
1891 let type_parameters =
1892 HasTypeParameters(&sig.generics,
1893 MethodRibKind(!sig.decl.has_self()));
1894 this.with_type_parameter_rib(type_parameters, |this| {
1895 visit::walk_impl_item(this, impl_item);
1898 ImplItemKind::Type(ref ty) => {
1899 // If this is a trait impl, ensure the type
1901 this.check_trait_item(impl_item.ident.name,
1904 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
1908 ImplItemKind::Macro(_) =>
1909 panic!("unexpanded macro in resolve!"),
1919 fn check_trait_item<F>(&self, name: Name, ns: Namespace, span: Span, err: F)
1920 where F: FnOnce(Name, &str) -> ResolutionError
1922 // If there is a TraitRef in scope for an impl, then the method must be in the
1924 if let Some((did, ref trait_ref)) = self.current_trait_ref {
1925 if !self.trait_item_map.contains_key(&(did, name, ns)) {
1926 let path_str = path_names_to_string(&trait_ref.path);
1927 resolve_error(self, span, err(name, &path_str));
1932 fn resolve_local(&mut self, local: &Local) {
1933 // Resolve the type.
1934 walk_list!(self, visit_ty, &local.ty);
1936 // Resolve the initializer.
1937 walk_list!(self, visit_expr, &local.init);
1939 // Resolve the pattern.
1940 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
1943 // build a map from pattern identifiers to binding-info's.
1944 // this is done hygienically. This could arise for a macro
1945 // that expands into an or-pattern where one 'x' was from the
1946 // user and one 'x' came from the macro.
1947 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
1948 let mut binding_map = FxHashMap();
1950 pat.walk(&mut |pat| {
1951 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
1952 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
1953 Some(Def::Local(..)) => true,
1956 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
1957 binding_map.insert(ident.node, binding_info);
1966 // check that all of the arms in an or-pattern have exactly the
1967 // same set of bindings, with the same binding modes for each.
1968 fn check_consistent_bindings(&mut self, arm: &Arm) {
1969 if arm.pats.is_empty() {
1973 let mut missing_vars = FxHashMap();
1974 let mut inconsistent_vars = FxHashMap();
1975 for (i, p) in arm.pats.iter().enumerate() {
1976 let map_i = self.binding_mode_map(&p);
1978 for (j, q) in arm.pats.iter().enumerate() {
1983 let map_j = self.binding_mode_map(&q);
1984 for (&key, &binding_i) in &map_i {
1985 if map_j.len() == 0 { // Account for missing bindings when
1986 let binding_error = missing_vars // map_j has none.
1988 .or_insert(BindingError {
1990 origin: BTreeSet::new(),
1991 target: BTreeSet::new(),
1993 binding_error.origin.insert(binding_i.span);
1994 binding_error.target.insert(q.span);
1996 for (&key_j, &binding_j) in &map_j {
1997 match map_i.get(&key_j) {
1998 None => { // missing binding
1999 let binding_error = missing_vars
2001 .or_insert(BindingError {
2003 origin: BTreeSet::new(),
2004 target: BTreeSet::new(),
2006 binding_error.origin.insert(binding_j.span);
2007 binding_error.target.insert(p.span);
2009 Some(binding_i) => { // check consistent binding
2010 if binding_i.binding_mode != binding_j.binding_mode {
2013 .or_insert((binding_j.span, binding_i.span));
2021 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2022 missing_vars.sort();
2023 for (_, v) in missing_vars {
2025 *v.origin.iter().next().unwrap(),
2026 ResolutionError::VariableNotBoundInPattern(v));
2028 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2029 inconsistent_vars.sort();
2030 for (name, v) in inconsistent_vars {
2031 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2035 fn resolve_arm(&mut self, arm: &Arm) {
2036 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2038 let mut bindings_list = FxHashMap();
2039 for pattern in &arm.pats {
2040 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2043 // This has to happen *after* we determine which
2044 // pat_idents are variants
2045 self.check_consistent_bindings(arm);
2047 walk_list!(self, visit_expr, &arm.guard);
2048 self.visit_expr(&arm.body);
2050 self.ribs[ValueNS].pop();
2053 fn resolve_block(&mut self, block: &Block) {
2054 debug!("(resolving block) entering block");
2055 // Move down in the graph, if there's an anonymous module rooted here.
2056 let orig_module = self.current_module;
2057 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2059 let mut num_macro_definition_ribs = 0;
2060 if let Some(anonymous_module) = anonymous_module {
2061 debug!("(resolving block) found anonymous module, moving down");
2062 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2063 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2064 self.current_module = anonymous_module;
2065 self.finalize_current_module_macro_resolutions();
2067 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2070 // Descend into the block.
2071 for stmt in &block.stmts {
2072 if let ast::StmtKind::Item(ref item) = stmt.node {
2073 if let ast::ItemKind::MacroDef(..) = item.node {
2074 num_macro_definition_ribs += 1;
2075 let def = self.definitions.local_def_id(item.id);
2076 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2077 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2081 self.visit_stmt(stmt);
2085 self.current_module = orig_module;
2086 for _ in 0 .. num_macro_definition_ribs {
2087 self.ribs[ValueNS].pop();
2088 self.label_ribs.pop();
2090 self.ribs[ValueNS].pop();
2091 if let Some(_) = anonymous_module {
2092 self.ribs[TypeNS].pop();
2094 debug!("(resolving block) leaving block");
2097 fn fresh_binding(&mut self,
2098 ident: &SpannedIdent,
2100 outer_pat_id: NodeId,
2101 pat_src: PatternSource,
2102 bindings: &mut FxHashMap<Ident, NodeId>)
2104 // Add the binding to the local ribs, if it
2105 // doesn't already exist in the bindings map. (We
2106 // must not add it if it's in the bindings map
2107 // because that breaks the assumptions later
2108 // passes make about or-patterns.)
2109 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2110 match bindings.get(&ident.node).cloned() {
2111 Some(id) if id == outer_pat_id => {
2112 // `Variant(a, a)`, error
2116 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2117 &ident.node.name.as_str())
2120 Some(..) if pat_src == PatternSource::FnParam => {
2121 // `fn f(a: u8, a: u8)`, error
2125 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2126 &ident.node.name.as_str())
2129 Some(..) if pat_src == PatternSource::Match => {
2130 // `Variant1(a) | Variant2(a)`, ok
2131 // Reuse definition from the first `a`.
2132 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2135 span_bug!(ident.span, "two bindings with the same name from \
2136 unexpected pattern source {:?}", pat_src);
2139 // A completely fresh binding, add to the lists if it's valid.
2140 if ident.node.name != keywords::Invalid.name() {
2141 bindings.insert(ident.node, outer_pat_id);
2142 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2147 PathResolution::new(def)
2150 fn resolve_pattern(&mut self,
2152 pat_src: PatternSource,
2153 // Maps idents to the node ID for the
2154 // outermost pattern that binds them.
2155 bindings: &mut FxHashMap<Ident, NodeId>) {
2156 // Visit all direct subpatterns of this pattern.
2157 let outer_pat_id = pat.id;
2158 pat.walk(&mut |pat| {
2160 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2161 // First try to resolve the identifier as some existing
2162 // entity, then fall back to a fresh binding.
2163 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2165 .and_then(LexicalScopeBinding::item);
2166 let resolution = binding.map(NameBinding::def).and_then(|def| {
2167 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2168 bmode != BindingMode::ByValue(Mutability::Immutable);
2170 Def::StructCtor(_, CtorKind::Const) |
2171 Def::VariantCtor(_, CtorKind::Const) |
2172 Def::Const(..) if !always_binding => {
2173 // A unit struct/variant or constant pattern.
2174 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2175 Some(PathResolution::new(def))
2177 Def::StructCtor(..) | Def::VariantCtor(..) |
2178 Def::Const(..) | Def::Static(..) => {
2179 // A fresh binding that shadows something unacceptable.
2183 ResolutionError::BindingShadowsSomethingUnacceptable(
2184 pat_src.descr(), ident.node.name, binding.unwrap())
2188 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2189 // These entities are explicitly allowed
2190 // to be shadowed by fresh bindings.
2194 span_bug!(ident.span, "unexpected definition for an \
2195 identifier in pattern: {:?}", def);
2198 }).unwrap_or_else(|| {
2199 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2202 self.record_def(pat.id, resolution);
2205 PatKind::TupleStruct(ref path, ..) => {
2206 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2209 PatKind::Path(ref qself, ref path) => {
2210 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2213 PatKind::Struct(ref path, ..) => {
2214 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2222 visit::walk_pat(self, pat);
2225 // High-level and context dependent path resolution routine.
2226 // Resolves the path and records the resolution into definition map.
2227 // If resolution fails tries several techniques to find likely
2228 // resolution candidates, suggest imports or other help, and report
2229 // errors in user friendly way.
2230 fn smart_resolve_path(&mut self,
2232 qself: Option<&QSelf>,
2236 let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
2237 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2238 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2241 fn smart_resolve_path_fragment(&mut self,
2243 qself: Option<&QSelf>,
2249 let ns = source.namespace();
2250 let is_expected = &|def| source.is_expected(def);
2251 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2253 // Base error is amended with one short label and possibly some longer helps/notes.
2254 let report_errors = |this: &mut Self, def: Option<Def>| {
2255 // Make the base error.
2256 let expected = source.descr_expected();
2257 let path_str = names_to_string(path);
2258 let code = source.error_code(def.is_some());
2259 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2260 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2261 format!("not a {}", expected), span)
2263 let item_str = path[path.len() - 1];
2264 let (mod_prefix, mod_str) = if path.len() == 1 {
2265 (format!(""), format!("this scope"))
2266 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2267 (format!(""), format!("the crate root"))
2269 let mod_path = &path[..path.len() - 1];
2270 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2271 PathResult::Module(module) => module.def(),
2273 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2274 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2276 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2277 format!("not found in {}", mod_str), ident_span)
2279 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2281 // Emit special messages for unresolved `Self` and `self`.
2282 if is_self_type(path, ns) {
2283 __diagnostic_used!(E0411);
2284 err.code("E0411".into());
2285 err.span_label(span, "`Self` is only available in traits and impls");
2288 if is_self_value(path, ns) {
2289 __diagnostic_used!(E0424);
2290 err.code("E0424".into());
2291 err.span_label(span, format!("`self` value is only available in \
2292 methods with `self` parameter"));
2296 // Try to lookup the name in more relaxed fashion for better error reporting.
2297 let name = path.last().unwrap().name;
2298 let candidates = this.lookup_import_candidates(name, ns, is_expected);
2299 if !candidates.is_empty() {
2300 let mut module_span = this.current_module.span;
2301 module_span.hi = module_span.lo;
2302 // Report import candidates as help and proceed searching for labels.
2303 show_candidates(&mut err, module_span, &candidates, def.is_some());
2304 } else if is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2305 let enum_candidates = this.lookup_import_candidates(name, ns, is_enum_variant);
2306 let mut enum_candidates = enum_candidates.iter()
2307 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2308 enum_candidates.sort();
2309 for (sp, variant_path, enum_path) in enum_candidates {
2310 let msg = format!("there is an enum variant `{}`, did you mean to use `{}`?",
2316 err.span_help(sp, &msg);
2320 if path.len() == 1 && this.self_type_is_available(span) {
2321 if let Some(candidate) = this.lookup_assoc_candidate(name, ns, is_expected) {
2322 let self_is_available = this.self_value_is_available(path[0].ctxt, span);
2324 AssocSuggestion::Field => {
2325 err.span_label(span, format!("did you mean `self.{}`?", path_str));
2326 if !self_is_available {
2327 err.span_label(span, format!("`self` value is only available in \
2328 methods with `self` parameter"));
2331 AssocSuggestion::MethodWithSelf if self_is_available => {
2332 err.span_label(span, format!("did you mean `self.{}(...)`?",
2335 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2336 err.span_label(span, format!("did you mean `Self::{}`?", path_str));
2343 let mut levenshtein_worked = false;
2346 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2347 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2348 levenshtein_worked = true;
2351 // Try context dependent help if relaxed lookup didn't work.
2352 if let Some(def) = def {
2353 match (def, source) {
2354 (Def::Macro(..), _) => {
2355 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2358 (Def::TyAlias(..), PathSource::Trait) => {
2359 err.span_label(span, "type aliases cannot be used for traits");
2362 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2363 ExprKind::Field(_, ident) => {
2364 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2365 path_str, ident.node));
2368 ExprKind::MethodCall(ident, ..) => {
2369 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2370 path_str, ident.node));
2375 _ if ns == ValueNS && is_struct_like(def) => {
2376 if let Def::Struct(def_id) = def {
2377 if let Some((ctor_def, ctor_vis))
2378 = this.struct_constructors.get(&def_id).cloned() {
2379 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2380 err.span_label(span, format!("constructor is not visible \
2381 here due to private fields"));
2385 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2394 if !levenshtein_worked {
2395 err.span_label(base_span, fallback_label);
2399 let report_errors = |this: &mut Self, def: Option<Def>| {
2400 report_errors(this, def).emit();
2401 err_path_resolution()
2404 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2405 source.defer_to_typeck(),
2406 source.global_by_default()) {
2407 Some(resolution) if resolution.unresolved_segments() == 0 => {
2408 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2411 // Add a temporary hack to smooth the transition to new struct ctor
2412 // visibility rules. See #38932 for more details.
2414 if let Def::Struct(def_id) = resolution.base_def() {
2415 if let Some((ctor_def, ctor_vis))
2416 = self.struct_constructors.get(&def_id).cloned() {
2417 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2418 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2419 self.session.add_lint(lint, id, span,
2420 "private struct constructors are not usable through \
2421 reexports in outer modules".to_string());
2422 res = Some(PathResolution::new(ctor_def));
2427 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2430 Some(resolution) if source.defer_to_typeck() => {
2431 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2432 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2433 // it needs to be added to the trait map.
2435 let item_name = path.last().unwrap().name;
2436 let traits = self.get_traits_containing_item(item_name, ns);
2437 self.trait_map.insert(id, traits);
2441 _ => report_errors(self, None)
2444 if let PathSource::TraitItem(..) = source {} else {
2445 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2446 self.record_def(id, resolution);
2451 fn self_type_is_available(&mut self, span: Span) -> bool {
2452 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2453 TypeNS, false, span);
2454 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2457 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2458 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2459 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2460 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2463 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2464 fn resolve_qpath_anywhere(&mut self,
2466 qself: Option<&QSelf>,
2468 primary_ns: Namespace,
2470 defer_to_typeck: bool,
2471 global_by_default: bool)
2472 -> Option<PathResolution> {
2473 let mut fin_res = None;
2474 // FIXME: can't resolve paths in macro namespace yet, macros are
2475 // processed by the little special hack below.
2476 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2477 if i == 0 || ns != primary_ns {
2478 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2479 // If defer_to_typeck, then resolution > no resolution,
2480 // otherwise full resolution > partial resolution > no resolution.
2481 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2483 res => if fin_res.is_none() { fin_res = res },
2487 let is_global = self.global_macros.get(&path[0].name).cloned()
2488 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2489 if primary_ns != MacroNS && (is_global || self.macro_names.contains(&path[0].name)) {
2490 // Return some dummy definition, it's enough for error reporting.
2492 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2498 /// Handles paths that may refer to associated items.
2499 fn resolve_qpath(&mut self,
2501 qself: Option<&QSelf>,
2505 global_by_default: bool)
2506 -> Option<PathResolution> {
2507 if let Some(qself) = qself {
2508 if qself.position == 0 {
2509 // FIXME: Create some fake resolution that can't possibly be a type.
2510 return Some(PathResolution::with_unresolved_segments(
2511 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2514 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2515 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2516 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2517 span, span, PathSource::TraitItem(ns));
2518 return Some(PathResolution::with_unresolved_segments(
2519 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2523 let result = match self.resolve_path(&path, Some(ns), true, span) {
2524 PathResult::NonModule(path_res) => path_res,
2525 PathResult::Module(module) if !module.is_normal() => {
2526 PathResolution::new(module.def().unwrap())
2528 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2529 // don't report an error right away, but try to fallback to a primitive type.
2530 // So, we are still able to successfully resolve something like
2532 // use std::u8; // bring module u8 in scope
2533 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2534 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2535 // // not to non-existent std::u8::max_value
2538 // Such behavior is required for backward compatibility.
2539 // The same fallback is used when `a` resolves to nothing.
2540 PathResult::Module(..) | PathResult::Failed(..)
2541 if (ns == TypeNS || path.len() > 1) &&
2542 self.primitive_type_table.primitive_types.contains_key(&path[0].name) => {
2543 let prim = self.primitive_type_table.primitive_types[&path[0].name];
2545 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2546 if !self.session.features.borrow().i128_type {
2547 emit_feature_err(&self.session.parse_sess,
2548 "i128_type", span, GateIssue::Language,
2549 "128-bit type is unstable");
2555 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2557 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2558 PathResult::Failed(msg, false) => {
2559 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2560 err_path_resolution()
2562 PathResult::Failed(..) => return None,
2563 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2566 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2567 path[0].name != keywords::CrateRoot.name() && path[0].name != "$crate" {
2568 let unqualified_result = {
2569 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2570 PathResult::NonModule(path_res) => path_res.base_def(),
2571 PathResult::Module(module) => module.def().unwrap(),
2572 _ => return Some(result),
2575 if result.base_def() == unqualified_result {
2576 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2577 self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
2584 fn resolve_path(&mut self,
2586 opt_ns: Option<Namespace>, // `None` indicates a module path
2590 let mut module = None;
2591 let mut allow_super = true;
2593 for (i, &ident) in path.iter().enumerate() {
2594 let is_last = i == path.len() - 1;
2595 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2597 if i == 0 && ns == TypeNS && ident.name == keywords::SelfValue.name() {
2598 module = Some(self.module_map[&self.current_module.normal_ancestor_id]);
2600 } else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() {
2601 let current_module = if i == 0 { self.current_module } else { module.unwrap() };
2602 let self_module = self.module_map[¤t_module.normal_ancestor_id];
2603 if let Some(parent) = self_module.parent {
2604 module = Some(self.module_map[&parent.normal_ancestor_id]);
2607 let msg = "There are too many initial `super`s.".to_string();
2608 return PathResult::Failed(msg, false);
2611 allow_super = false;
2613 if i == 0 && ns == TypeNS && ident.name == keywords::CrateRoot.name() {
2614 module = Some(self.graph_root);
2616 } else if i == 0 && ns == TypeNS && ident.name == "$crate" {
2617 module = Some(self.resolve_crate_var(ident.ctxt, path_span));
2621 let binding = if let Some(module) = module {
2622 self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
2623 } else if opt_ns == Some(MacroNS) {
2624 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
2625 .map(MacroBinding::binding)
2627 match self.resolve_ident_in_lexical_scope(ident, ns, record_used, path_span) {
2628 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2629 Some(LexicalScopeBinding::Def(def))
2630 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2631 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2635 _ => Err(if record_used { Determined } else { Undetermined }),
2641 let def = binding.def();
2642 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2643 if let Some(next_module) = binding.module() {
2644 module = Some(next_module);
2645 } else if def == Def::Err {
2646 return PathResult::NonModule(err_path_resolution());
2647 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2648 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2649 def, path.len() - i - 1
2652 return PathResult::Failed(format!("Not a module `{}`", ident), is_last);
2655 Err(Undetermined) => return PathResult::Indeterminate,
2656 Err(Determined) => {
2657 if let Some(module) = module {
2658 if opt_ns.is_some() && !module.is_normal() {
2659 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2660 module.def().unwrap(), path.len() - i
2664 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2665 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2666 let mut candidates =
2667 self.lookup_import_candidates(ident.name, TypeNS, is_mod);
2668 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2669 if let Some(candidate) = candidates.get(0) {
2670 format!("Did you mean `{}`?", candidate.path)
2672 format!("Maybe a missing `extern crate {};`?", ident)
2675 format!("Use of undeclared type or module `{}`", ident)
2677 format!("Could not find `{}` in `{}`", ident, path[i - 1])
2679 return PathResult::Failed(msg, is_last);
2684 PathResult::Module(module.unwrap_or(self.graph_root))
2687 // Resolve a local definition, potentially adjusting for closures.
2688 fn adjust_local_def(&mut self,
2693 span: Span) -> Def {
2694 let ribs = &self.ribs[ns][rib_index + 1..];
2696 // An invalid forward use of a type parameter from a previous default.
2697 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2699 resolve_error(self, span,
2700 ResolutionError::ForwardDeclaredTyParam);
2702 assert_eq!(def, Def::Err);
2708 span_bug!(span, "unexpected {:?} in bindings", def)
2710 Def::Local(def_id) => {
2713 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2714 ForwardTyParamBanRibKind => {
2715 // Nothing to do. Continue.
2717 ClosureRibKind(function_id) => {
2719 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2721 let seen = self.freevars_seen
2723 .or_insert_with(|| NodeMap());
2724 if let Some(&index) = seen.get(&node_id) {
2725 def = Def::Upvar(def_id, index, function_id);
2728 let vec = self.freevars
2730 .or_insert_with(|| vec![]);
2731 let depth = vec.len();
2732 def = Def::Upvar(def_id, depth, function_id);
2739 seen.insert(node_id, depth);
2742 ItemRibKind | MethodRibKind(_) => {
2743 // This was an attempt to access an upvar inside a
2744 // named function item. This is not allowed, so we
2747 resolve_error(self, span,
2748 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2752 ConstantItemRibKind => {
2753 // Still doesn't deal with upvars
2755 resolve_error(self, span,
2756 ResolutionError::AttemptToUseNonConstantValueInConstant);
2763 Def::TyParam(..) | Def::SelfTy(..) => {
2766 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2767 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
2768 ConstantItemRibKind => {
2769 // Nothing to do. Continue.
2772 // This was an attempt to use a type parameter outside
2775 resolve_error(self, span,
2776 ResolutionError::TypeParametersFromOuterFunction);
2788 // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
2789 // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
2790 // FIXME #34673: This needs testing.
2791 pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
2792 where F: FnOnce(&mut Resolver<'a>) -> T,
2794 self.with_empty_ribs(|this| {
2795 this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2796 this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2801 fn with_empty_ribs<T, F>(&mut self, f: F) -> T
2802 where F: FnOnce(&mut Resolver<'a>) -> T,
2804 let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
2805 let label_ribs = replace(&mut self.label_ribs, Vec::new());
2807 let result = f(self);
2809 self.label_ribs = label_ribs;
2813 fn lookup_assoc_candidate<FilterFn>(&mut self,
2816 filter_fn: FilterFn)
2817 -> Option<AssocSuggestion>
2818 where FilterFn: Fn(Def) -> bool
2820 fn extract_node_id(t: &Ty) -> Option<NodeId> {
2822 TyKind::Path(None, _) => Some(t.id),
2823 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
2824 // This doesn't handle the remaining `Ty` variants as they are not
2825 // that commonly the self_type, it might be interesting to provide
2826 // support for those in future.
2831 // Fields are generally expected in the same contexts as locals.
2832 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
2833 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
2834 // Look for a field with the same name in the current self_type.
2835 if let Some(resolution) = self.def_map.get(&node_id) {
2836 match resolution.base_def() {
2837 Def::Struct(did) | Def::Union(did)
2838 if resolution.unresolved_segments() == 0 => {
2839 if let Some(field_names) = self.field_names.get(&did) {
2840 if field_names.iter().any(|&field_name| name == field_name) {
2841 return Some(AssocSuggestion::Field);
2851 // Look for associated items in the current trait.
2852 if let Some((trait_did, _)) = self.current_trait_ref {
2853 if let Some(&(def, has_self)) = self.trait_item_map.get(&(trait_did, name, ns)) {
2855 return Some(if has_self {
2856 AssocSuggestion::MethodWithSelf
2858 AssocSuggestion::AssocItem
2867 fn lookup_typo_candidate<FilterFn>(&mut self,
2870 filter_fn: FilterFn,
2873 where FilterFn: Fn(Def) -> bool
2875 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
2876 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
2877 if let Some(binding) = resolution.borrow().binding {
2878 if filter_fn(binding.def()) {
2879 names.push(ident.name);
2885 let mut names = Vec::new();
2886 if path.len() == 1 {
2887 // Search in lexical scope.
2888 // Walk backwards up the ribs in scope and collect candidates.
2889 for rib in self.ribs[ns].iter().rev() {
2890 // Locals and type parameters
2891 for (ident, def) in &rib.bindings {
2892 if filter_fn(*def) {
2893 names.push(ident.name);
2897 if let ModuleRibKind(module) = rib.kind {
2898 // Items from this module
2899 add_module_candidates(module, &mut names);
2901 if let ModuleKind::Block(..) = module.kind {
2902 // We can see through blocks
2904 // Items from the prelude
2905 if let Some(prelude) = self.prelude {
2906 if !module.no_implicit_prelude {
2907 add_module_candidates(prelude, &mut names);
2914 // Add primitive types to the mix
2915 if filter_fn(Def::PrimTy(TyBool)) {
2916 for (name, _) in &self.primitive_type_table.primitive_types {
2921 // Search in module.
2922 let mod_path = &path[..path.len() - 1];
2923 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
2925 add_module_candidates(module, &mut names);
2929 let name = path[path.len() - 1].name;
2930 // Make sure error reporting is deterministic.
2931 names.sort_by_key(|name| name.as_str());
2932 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
2933 Some(found) if found != name => Some(found),
2938 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
2939 where F: FnOnce(&mut Resolver)
2941 if let Some(label) = label {
2942 let def = Def::Label(id);
2943 self.with_label_rib(|this| {
2944 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
2952 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
2953 self.with_resolved_label(label, id, |this| this.visit_block(block));
2956 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
2957 // First, record candidate traits for this expression if it could
2958 // result in the invocation of a method call.
2960 self.record_candidate_traits_for_expr_if_necessary(expr);
2962 // Next, resolve the node.
2964 ExprKind::Path(ref qself, ref path) => {
2965 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
2966 visit::walk_expr(self, expr);
2969 ExprKind::Struct(ref path, ..) => {
2970 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
2971 visit::walk_expr(self, expr);
2974 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
2975 match self.search_label(label.node) {
2977 self.record_def(expr.id, err_path_resolution());
2980 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
2982 Some(def @ Def::Label(_)) => {
2983 // Since this def is a label, it is never read.
2984 self.record_def(expr.id, PathResolution::new(def));
2987 span_bug!(expr.span, "label wasn't mapped to a label def!");
2991 // visit `break` argument if any
2992 visit::walk_expr(self, expr);
2995 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
2996 self.visit_expr(subexpression);
2998 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2999 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
3000 self.visit_block(if_block);
3001 self.ribs[ValueNS].pop();
3003 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3006 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3008 ExprKind::While(ref subexpression, ref block, label) => {
3009 self.with_resolved_label(label, expr.id, |this| {
3010 this.visit_expr(subexpression);
3011 this.visit_block(block);
3015 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3016 self.with_resolved_label(label, expr.id, |this| {
3017 this.visit_expr(subexpression);
3018 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3019 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3020 this.visit_block(block);
3021 this.ribs[ValueNS].pop();
3025 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3026 self.visit_expr(subexpression);
3027 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3028 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3030 self.resolve_labeled_block(label, expr.id, block);
3032 self.ribs[ValueNS].pop();
3035 // Equivalent to `visit::walk_expr` + passing some context to children.
3036 ExprKind::Field(ref subexpression, _) => {
3037 self.resolve_expr(subexpression, Some(expr));
3039 ExprKind::MethodCall(_, ref types, ref arguments) => {
3040 let mut arguments = arguments.iter();
3041 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3042 for argument in arguments {
3043 self.resolve_expr(argument, None);
3045 for ty in types.iter() {
3050 ExprKind::Repeat(ref element, ref count) => {
3051 self.visit_expr(element);
3052 self.with_constant_rib(|this| {
3053 this.visit_expr(count);
3056 ExprKind::Call(ref callee, ref arguments) => {
3057 self.resolve_expr(callee, Some(expr));
3058 for argument in arguments {
3059 self.resolve_expr(argument, None);
3064 visit::walk_expr(self, expr);
3069 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3071 ExprKind::Field(_, name) => {
3072 // FIXME(#6890): Even though you can't treat a method like a
3073 // field, we need to add any trait methods we find that match
3074 // the field name so that we can do some nice error reporting
3075 // later on in typeck.
3076 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3077 self.trait_map.insert(expr.id, traits);
3079 ExprKind::MethodCall(name, ..) => {
3080 debug!("(recording candidate traits for expr) recording traits for {}",
3082 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3083 self.trait_map.insert(expr.id, traits);
3091 fn get_traits_containing_item(&mut self, name: Name, ns: Namespace) -> Vec<TraitCandidate> {
3092 debug!("(getting traits containing item) looking for '{}'", name);
3094 let mut found_traits = Vec::new();
3095 // Look for the current trait.
3096 if let Some((trait_def_id, _)) = self.current_trait_ref {
3097 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3098 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: None });
3102 let mut search_module = self.current_module;
3104 self.get_traits_in_module_containing_item(name, ns, search_module, &mut found_traits);
3105 match search_module.kind {
3106 ModuleKind::Block(..) => search_module = search_module.parent.unwrap(),
3111 if let Some(prelude) = self.prelude {
3112 if !search_module.no_implicit_prelude {
3113 self.get_traits_in_module_containing_item(name, ns, prelude, &mut found_traits);
3120 fn get_traits_in_module_containing_item(&mut self,
3124 found_traits: &mut Vec<TraitCandidate>) {
3125 let mut traits = module.traits.borrow_mut();
3126 if traits.is_none() {
3127 let mut collected_traits = Vec::new();
3128 module.for_each_child(|name, ns, binding| {
3129 if ns != TypeNS { return }
3130 if let Def::Trait(_) = binding.def() {
3131 collected_traits.push((name, binding));
3134 *traits = Some(collected_traits.into_boxed_slice());
3137 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3138 let trait_def_id = binding.def().def_id();
3139 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3140 let import_id = match binding.kind {
3141 NameBindingKind::Import { directive, .. } => {
3142 self.maybe_unused_trait_imports.insert(directive.id);
3143 self.add_to_glob_map(directive.id, trait_name);
3148 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3153 /// When name resolution fails, this method can be used to look up candidate
3154 /// entities with the expected name. It allows filtering them using the
3155 /// supplied predicate (which should be used to only accept the types of
3156 /// definitions expected e.g. traits). The lookup spans across all crates.
3158 /// NOTE: The method does not look into imports, but this is not a problem,
3159 /// since we report the definitions (thus, the de-aliased imports).
3160 fn lookup_import_candidates<FilterFn>(&mut self,
3162 namespace: Namespace,
3163 filter_fn: FilterFn)
3164 -> Vec<ImportSuggestion>
3165 where FilterFn: Fn(Def) -> bool
3167 let mut candidates = Vec::new();
3168 let mut worklist = Vec::new();
3169 let mut seen_modules = FxHashSet();
3170 worklist.push((self.graph_root, Vec::new(), false));
3172 while let Some((in_module,
3174 in_module_is_extern)) = worklist.pop() {
3175 self.populate_module_if_necessary(in_module);
3177 in_module.for_each_child(|ident, ns, name_binding| {
3179 // avoid imports entirely
3180 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3181 // avoid non-importable candidates as well
3182 if !name_binding.is_importable() { return; }
3184 // collect results based on the filter function
3185 if ident.name == lookup_name && ns == namespace {
3186 if filter_fn(name_binding.def()) {
3188 let mut segms = path_segments.clone();
3189 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3191 span: name_binding.span,
3194 // the entity is accessible in the following cases:
3195 // 1. if it's defined in the same crate, it's always
3196 // accessible (since private entities can be made public)
3197 // 2. if it's defined in another crate, it's accessible
3198 // only if both the module is public and the entity is
3199 // declared as public (due to pruning, we don't explore
3200 // outside crate private modules => no need to check this)
3201 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3202 candidates.push(ImportSuggestion { path: path });
3207 // collect submodules to explore
3208 if let Some(module) = name_binding.module() {
3210 let mut path_segments = path_segments.clone();
3211 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3213 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3214 // add the module to the lookup
3215 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3216 if seen_modules.insert(module.def_id().unwrap()) {
3217 worklist.push((module, path_segments, is_extern));
3227 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3228 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3229 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3230 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3234 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3236 ast::Visibility::Public => ty::Visibility::Public,
3237 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3238 ast::Visibility::Inherited => {
3239 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3241 ast::Visibility::Restricted { ref path, id } => {
3242 let def = self.smart_resolve_path(id, None, path,
3243 PathSource::Visibility).base_def();
3244 if def == Def::Err {
3245 ty::Visibility::Public
3247 let vis = ty::Visibility::Restricted(def.def_id());
3248 if self.is_accessible(vis) {
3251 self.session.span_err(path.span, "visibilities can only be restricted \
3252 to ancestor modules");
3253 ty::Visibility::Public
3260 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3261 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3264 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3265 vis.is_accessible_from(module.normal_ancestor_id, self)
3268 fn report_errors(&mut self) {
3269 self.report_shadowing_errors();
3270 let mut reported_spans = FxHashSet();
3272 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3273 if !reported_spans.insert(span) { continue }
3274 let participle = |binding: &NameBinding| {
3275 if binding.is_import() { "imported" } else { "defined" }
3277 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3278 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3279 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3280 format!("consider adding an explicit import of `{}` to disambiguate", name)
3281 } else if let Def::Macro(..) = b1.def() {
3282 format!("macro-expanded {} do not shadow",
3283 if b1.is_import() { "macro imports" } else { "macros" })
3285 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3286 if b1.is_import() { "imports" } else { "items" })
3289 let id = match b2.kind {
3290 NameBindingKind::Import { directive, .. } => directive.id,
3291 _ => unreachable!(),
3293 let mut span = MultiSpan::from_span(span);
3294 span.push_span_label(b1.span, msg1);
3295 span.push_span_label(b2.span, msg2);
3296 let msg = format!("`{}` is ambiguous", name);
3297 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3300 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3301 err.span_note(b1.span, &msg1);
3303 Def::Macro(..) if b2.span == DUMMY_SP =>
3304 err.note(&format!("`{}` is also a builtin macro", name)),
3305 _ => err.span_note(b2.span, &msg2),
3307 err.note(¬e).emit();
3311 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3312 if !reported_spans.insert(span) { continue }
3313 if binding.is_extern_crate() {
3314 // Warn when using an inaccessible extern crate.
3315 let node_id = match binding.kind {
3316 NameBindingKind::Import { directive, .. } => directive.id,
3317 _ => unreachable!(),
3319 let msg = format!("extern crate `{}` is private", name);
3320 self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
3322 let def = binding.def();
3323 self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
3328 fn report_shadowing_errors(&mut self) {
3329 for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3330 self.resolve_legacy_scope(scope, name, true);
3333 let mut reported_errors = FxHashSet();
3334 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3335 if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() &&
3336 reported_errors.insert((binding.name, binding.span)) {
3337 let msg = format!("`{}` is already in scope", binding.name);
3338 self.session.struct_span_err(binding.span, &msg)
3339 .note("macro-expanded `macro_rules!`s may not shadow \
3340 existing macros (see RFC 1560)")
3346 fn report_conflict(&mut self,
3350 binding: &NameBinding,
3351 old_binding: &NameBinding) {
3352 // Error on the second of two conflicting names
3353 if old_binding.span.lo > binding.span.lo {
3354 return self.report_conflict(parent, ident, ns, old_binding, binding);
3357 let container = match parent.kind {
3358 ModuleKind::Def(Def::Mod(_), _) => "module",
3359 ModuleKind::Def(Def::Trait(_), _) => "trait",
3360 ModuleKind::Block(..) => "block",
3364 let (participle, noun) = match old_binding.is_import() {
3365 true => ("imported", "import"),
3366 false => ("defined", "definition"),
3369 let (name, span) = (ident.name, binding.span);
3371 if let Some(s) = self.name_already_seen.get(&name) {
3378 let kind = match (ns, old_binding.module()) {
3379 (ValueNS, _) => "a value",
3380 (MacroNS, _) => "a macro",
3381 (TypeNS, _) if old_binding.is_extern_crate() => "an extern crate",
3382 (TypeNS, Some(module)) if module.is_normal() => "a module",
3383 (TypeNS, Some(module)) if module.is_trait() => "a trait",
3384 (TypeNS, _) => "a type",
3386 format!("{} named `{}` has already been {} in this {}",
3387 kind, name, participle, container)
3390 let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
3391 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3392 (true, _) | (_, true) => match binding.is_import() && old_binding.is_import() {
3393 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3394 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3396 _ => match (old_binding.is_import(), binding.is_import()) {
3397 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3398 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3399 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3403 err.span_label(span, format!("`{}` already {}", name, participle));
3404 if old_binding.span != syntax_pos::DUMMY_SP {
3405 err.span_label(old_binding.span, format!("previous {} of `{}` here", noun, name));
3408 self.name_already_seen.insert(name, span);
3411 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3412 let (id, span) = (directive.id, directive.span);
3413 let msg = "`self` no longer imports values".to_string();
3414 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3417 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3418 if self.proc_macro_enabled { return; }
3421 if attr.path.segments.len() > 1 {
3424 let ident = attr.path.segments[0].identifier;
3425 let result = self.resolve_lexical_macro_path_segment(ident,
3429 if let Ok(binding) = result {
3430 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3431 attr::mark_known(attr);
3433 let msg = "attribute procedural macros are experimental";
3434 let feature = "proc_macro";
3436 feature_err(&self.session.parse_sess, feature,
3437 attr.span, GateIssue::Language, msg)
3438 .span_note(binding.span(), "procedural macro imported here")
3446 fn is_struct_like(def: Def) -> bool {
3448 Def::VariantCtor(_, CtorKind::Fictive) => true,
3449 _ => PathSource::Struct.is_expected(def),
3453 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
3454 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
3457 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
3458 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
3461 fn names_to_string(idents: &[Ident]) -> String {
3462 let mut result = String::new();
3463 for (i, ident) in idents.iter().filter(|i| i.name != keywords::CrateRoot.name()).enumerate() {
3465 result.push_str("::");
3467 result.push_str(&ident.name.as_str());
3472 fn path_names_to_string(path: &Path) -> String {
3473 names_to_string(&path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>())
3476 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3477 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3478 let variant_path = &suggestion.path;
3479 let variant_path_string = path_names_to_string(variant_path);
3481 let path_len = suggestion.path.segments.len();
3482 let enum_path = ast::Path {
3483 span: suggestion.path.span,
3484 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3486 let enum_path_string = path_names_to_string(&enum_path);
3488 (suggestion.path.span, variant_path_string, enum_path_string)
3492 /// When an entity with a given name is not available in scope, we search for
3493 /// entities with that name in all crates. This method allows outputting the
3494 /// results of this search in a programmer-friendly way
3495 fn show_candidates(err: &mut DiagnosticBuilder,
3497 candidates: &[ImportSuggestion],
3500 // we want consistent results across executions, but candidates are produced
3501 // by iterating through a hash map, so make sure they are ordered:
3502 let mut path_strings: Vec<_> =
3503 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3504 path_strings.sort();
3506 let better = if better { "better " } else { "" };
3507 let msg_diff = match path_strings.len() {
3508 1 => " is found in another module, you can import it",
3509 _ => "s are found in other modules, you can import them",
3511 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3513 for candidate in &mut path_strings {
3514 *candidate = format!("use {};\n", candidate);
3517 err.span_suggestions(span, &msg, path_strings);
3520 /// A somewhat inefficient routine to obtain the name of a module.
3521 fn module_to_string(module: Module) -> String {
3522 let mut names = Vec::new();
3524 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3525 if let ModuleKind::Def(_, name) = module.kind {
3526 if let Some(parent) = module.parent {
3527 names.push(Ident::with_empty_ctxt(name));
3528 collect_mod(names, parent);
3531 // danger, shouldn't be ident?
3532 names.push(Ident::from_str("<opaque>"));
3533 collect_mod(names, module.parent.unwrap());
3536 collect_mod(&mut names, module);
3538 if names.is_empty() {
3539 return "???".to_string();
3541 names_to_string(&names.into_iter().rev().collect::<Vec<_>>())
3544 fn err_path_resolution() -> PathResolution {
3545 PathResolution::new(Def::Err)
3548 #[derive(PartialEq,Copy, Clone)]
3549 pub enum MakeGlobMap {
3554 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }