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 #![unstable(feature = "rustc_private", issue = "27812")]
13 #![crate_type = "dylib"]
14 #![crate_type = "rlib"]
15 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
16 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
17 html_root_url = "https://doc.rust-lang.org/nightly/")]
20 #![feature(associated_consts)]
21 #![feature(rustc_diagnostic_macros)]
22 #![feature(rustc_private)]
23 #![feature(staged_api)]
29 extern crate syntax_pos;
30 extern crate rustc_errors as errors;
35 use self::Namespace::*;
36 use self::TypeParameters::*;
39 use rustc::hir::map::{Definitions, DefCollector};
40 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
41 use rustc::middle::cstore::CrateLoader;
42 use rustc::session::Session;
44 use rustc::hir::def::*;
45 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
47 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
48 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
50 use syntax::ext::hygiene::{Mark, SyntaxContext};
51 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
52 use syntax::ext::base::SyntaxExtension;
53 use syntax::ext::base::Determinacy::{Determined, Undetermined};
54 use syntax::ext::base::MacroKind;
55 use syntax::symbol::{Symbol, keywords};
56 use syntax::util::lev_distance::find_best_match_for_name;
58 use syntax::visit::{self, FnKind, Visitor};
60 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
61 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
62 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
63 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
64 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
65 use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
67 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
68 use errors::DiagnosticBuilder;
70 use std::cell::{Cell, RefCell};
72 use std::collections::BTreeSet;
74 use std::mem::replace;
77 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
78 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
80 // NB: This module needs to be declared first so diagnostics are
81 // registered before they are used.
86 mod build_reduced_graph;
89 /// A free importable items suggested in case of resolution failure.
90 struct ImportSuggestion {
94 /// A field or associated item from self type suggested in case of resolution failure.
95 enum AssocSuggestion {
102 struct BindingError {
104 origin: BTreeSet<Span>,
105 target: BTreeSet<Span>,
108 impl PartialOrd for BindingError {
109 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
110 Some(self.cmp(other))
114 impl PartialEq for BindingError {
115 fn eq(&self, other: &BindingError) -> bool {
116 self.name == other.name
120 impl Ord for BindingError {
121 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
122 self.name.cmp(&other.name)
126 enum ResolutionError<'a> {
127 /// error E0401: can't use type parameters from outer function
128 TypeParametersFromOuterFunction,
129 /// error E0402: cannot use an outer type parameter in this context
130 OuterTypeParameterContext,
131 /// error E0403: the name is already used for a type parameter in this type parameter list
132 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
133 /// error E0407: method is not a member of trait
134 MethodNotMemberOfTrait(Name, &'a str),
135 /// error E0437: type is not a member of trait
136 TypeNotMemberOfTrait(Name, &'a str),
137 /// error E0438: const is not a member of trait
138 ConstNotMemberOfTrait(Name, &'a str),
139 /// error E0408: variable `{}` is not bound in all patterns
140 VariableNotBoundInPattern(&'a BindingError),
141 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
142 VariableBoundWithDifferentMode(Name, Span),
143 /// error E0415: identifier is bound more than once in this parameter list
144 IdentifierBoundMoreThanOnceInParameterList(&'a str),
145 /// error E0416: identifier is bound more than once in the same pattern
146 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
147 /// error E0426: use of undeclared label
148 UndeclaredLabel(&'a str),
149 /// error E0429: `self` imports are only allowed within a { } list
150 SelfImportsOnlyAllowedWithin,
151 /// error E0430: `self` import can only appear once in the list
152 SelfImportCanOnlyAppearOnceInTheList,
153 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
154 SelfImportOnlyInImportListWithNonEmptyPrefix,
155 /// error E0432: unresolved import
156 UnresolvedImport(Option<(&'a str, &'a str)>),
157 /// error E0433: failed to resolve
158 FailedToResolve(&'a str),
159 /// error E0434: can't capture dynamic environment in a fn item
160 CannotCaptureDynamicEnvironmentInFnItem,
161 /// error E0435: attempt to use a non-constant value in a constant
162 AttemptToUseNonConstantValueInConstant,
163 /// error E0530: X bindings cannot shadow Ys
164 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
165 /// error E0128: type parameters with a default cannot use forward declared identifiers
166 ForwardDeclaredTyParam,
169 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
171 resolution_error: ResolutionError<'a>) {
172 resolve_struct_error(resolver, span, resolution_error).emit();
175 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
177 resolution_error: ResolutionError<'a>)
178 -> DiagnosticBuilder<'sess> {
179 match resolution_error {
180 ResolutionError::TypeParametersFromOuterFunction => {
181 let mut err = struct_span_err!(resolver.session,
184 "can't use type parameters from outer function; \
185 try using a local type parameter instead");
186 err.span_label(span, &format!("use of type variable from outer function"));
189 ResolutionError::OuterTypeParameterContext => {
190 struct_span_err!(resolver.session,
193 "cannot use an outer type parameter in this context")
195 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
196 let mut err = struct_span_err!(resolver.session,
199 "the name `{}` is already used for a type parameter \
200 in this type parameter list",
202 err.span_label(span, &format!("already used"));
203 err.span_label(first_use_span.clone(), &format!("first use of `{}`", name));
206 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
207 let mut err = struct_span_err!(resolver.session,
210 "method `{}` is not a member of trait `{}`",
213 err.span_label(span, &format!("not a member of trait `{}`", trait_));
216 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
217 let mut err = struct_span_err!(resolver.session,
220 "type `{}` is not a member of trait `{}`",
223 err.span_label(span, &format!("not a member of trait `{}`", trait_));
226 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
227 let mut err = struct_span_err!(resolver.session,
230 "const `{}` is not a member of trait `{}`",
233 err.span_label(span, &format!("not a member of trait `{}`", trait_));
236 ResolutionError::VariableNotBoundInPattern(binding_error) => {
237 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
238 let msp = MultiSpan::from_spans(target_sp.clone());
239 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
240 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
241 for sp in target_sp {
242 err.span_label(sp, &format!("pattern doesn't bind `{}`", binding_error.name));
244 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
245 for sp in origin_sp {
246 err.span_label(sp, &"variable not in all patterns");
250 ResolutionError::VariableBoundWithDifferentMode(variable_name,
251 first_binding_span) => {
252 let mut err = struct_span_err!(resolver.session,
255 "variable `{}` is bound in inconsistent \
256 ways within the same match arm",
258 err.span_label(span, &format!("bound in different ways"));
259 err.span_label(first_binding_span, &format!("first binding"));
262 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
263 let mut err = struct_span_err!(resolver.session,
266 "identifier `{}` is bound more than once in this parameter list",
268 err.span_label(span, &format!("used as parameter more than once"));
271 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
272 let mut err = struct_span_err!(resolver.session,
275 "identifier `{}` is bound more than once in the same pattern",
277 err.span_label(span, &format!("used in a pattern more than once"));
280 ResolutionError::UndeclaredLabel(name) => {
281 let mut err = struct_span_err!(resolver.session,
284 "use of undeclared label `{}`",
286 err.span_label(span, &format!("undeclared label `{}`",&name));
289 ResolutionError::SelfImportsOnlyAllowedWithin => {
290 struct_span_err!(resolver.session,
294 "`self` imports are only allowed within a { } list")
296 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
297 struct_span_err!(resolver.session,
300 "`self` import can only appear once in the list")
302 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
303 struct_span_err!(resolver.session,
306 "`self` import can only appear in an import list with a \
309 ResolutionError::UnresolvedImport(name) => {
310 let msg = match name {
311 Some((n, _)) => format!("unresolved import `{}`", n),
312 None => "unresolved import".to_owned(),
314 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
315 if let Some((_, p)) = name {
316 err.span_label(span, &p);
320 ResolutionError::FailedToResolve(msg) => {
321 let mut err = struct_span_err!(resolver.session, span, E0433,
322 "failed to resolve. {}", msg);
323 err.span_label(span, &msg);
326 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
327 struct_span_err!(resolver.session,
331 "can't capture dynamic environment in a fn item; use the || { ... } \
332 closure form instead")
334 ResolutionError::AttemptToUseNonConstantValueInConstant => {
335 let mut err = struct_span_err!(resolver.session,
338 "attempt to use a non-constant value in a constant");
339 err.span_label(span, &format!("non-constant used with constant"));
342 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
343 let shadows_what = PathResolution::new(binding.def()).kind_name();
344 let mut err = struct_span_err!(resolver.session,
347 "{}s cannot shadow {}s", what_binding, shadows_what);
348 err.span_label(span, &format!("cannot be named the same as a {}", shadows_what));
349 let participle = if binding.is_import() { "imported" } else { "defined" };
350 let msg = &format!("a {} `{}` is {} here", shadows_what, name, participle);
351 err.span_label(binding.span, msg);
354 ResolutionError::ForwardDeclaredTyParam => {
355 let mut err = struct_span_err!(resolver.session, span, E0128,
356 "type parameters with a default cannot use \
357 forward declared identifiers");
358 err.span_label(span, &format!("defaulted type parameters \
359 cannot be forward declared"));
365 #[derive(Copy, Clone, Debug)]
368 binding_mode: BindingMode,
371 // Map from the name in a pattern to its binding mode.
372 type BindingMap = FxHashMap<Ident, BindingInfo>;
374 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
385 fn is_refutable(self) -> bool {
387 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
388 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
391 fn descr(self) -> &'static str {
393 PatternSource::Match => "match binding",
394 PatternSource::IfLet => "if let binding",
395 PatternSource::WhileLet => "while let binding",
396 PatternSource::Let => "let binding",
397 PatternSource::For => "for binding",
398 PatternSource::FnParam => "function parameter",
403 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
404 enum PathSource<'a> {
405 // Type paths `Path`.
407 // Trait paths in bounds or impls.
409 // Expression paths `path`, with optional parent context.
410 Expr(Option<&'a Expr>),
411 // Paths in path patterns `Path`.
413 // Paths in struct expressions and patterns `Path { .. }`.
415 // Paths in tuple struct patterns `Path(..)`.
417 // `m::A::B` in `<T as m::A>::B::C`.
418 TraitItem(Namespace),
419 // Path in `pub(path)`
421 // Path in `use a::b::{...};`
425 impl<'a> PathSource<'a> {
426 fn namespace(self) -> Namespace {
428 PathSource::Type | PathSource::Trait | PathSource::Struct |
429 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
430 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
431 PathSource::TraitItem(ns) => ns,
435 fn global_by_default(self) -> bool {
437 PathSource::Visibility | PathSource::ImportPrefix => true,
438 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
439 PathSource::Struct | PathSource::TupleStruct |
440 PathSource::Trait | PathSource::TraitItem(..) => false,
444 fn defer_to_typeck(self) -> bool {
446 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
447 PathSource::Struct | PathSource::TupleStruct => true,
448 PathSource::Trait | PathSource::TraitItem(..) |
449 PathSource::Visibility | PathSource::ImportPrefix => false,
453 fn descr_expected(self) -> &'static str {
455 PathSource::Type => "type",
456 PathSource::Trait => "trait",
457 PathSource::Pat => "unit struct/variant or constant",
458 PathSource::Struct => "struct, variant or union type",
459 PathSource::TupleStruct => "tuple struct/variant",
460 PathSource::Visibility => "module",
461 PathSource::ImportPrefix => "module or enum",
462 PathSource::TraitItem(ns) => match ns {
463 TypeNS => "associated type",
464 ValueNS => "method or associated constant",
465 MacroNS => bug!("associated macro"),
467 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
468 // "function" here means "anything callable" rather than `Def::Fn`,
469 // this is not precise but usually more helpful than just "value".
470 Some(&ExprKind::Call(..)) => "function",
476 fn is_expected(self, def: Def) -> bool {
478 PathSource::Type => match def {
479 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
480 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
481 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
484 PathSource::Trait => match def {
485 Def::Trait(..) => true,
488 PathSource::Expr(..) => match def {
489 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
490 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
491 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
492 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
495 PathSource::Pat => match def {
496 Def::StructCtor(_, CtorKind::Const) |
497 Def::VariantCtor(_, CtorKind::Const) |
498 Def::Const(..) | Def::AssociatedConst(..) => true,
501 PathSource::TupleStruct => match def {
502 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
505 PathSource::Struct => match def {
506 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
507 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
510 PathSource::TraitItem(ns) => match def {
511 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
512 Def::AssociatedTy(..) if ns == TypeNS => true,
515 PathSource::ImportPrefix => match def {
516 Def::Mod(..) | Def::Enum(..) => true,
519 PathSource::Visibility => match def {
520 Def::Mod(..) => true,
526 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
527 __diagnostic_used!(E0404);
528 __diagnostic_used!(E0405);
529 __diagnostic_used!(E0412);
530 __diagnostic_used!(E0422);
531 __diagnostic_used!(E0423);
532 __diagnostic_used!(E0425);
533 __diagnostic_used!(E0531);
534 __diagnostic_used!(E0532);
535 __diagnostic_used!(E0573);
536 __diagnostic_used!(E0574);
537 __diagnostic_used!(E0575);
538 __diagnostic_used!(E0576);
539 __diagnostic_used!(E0577);
540 __diagnostic_used!(E0578);
541 match (self, has_unexpected_resolution) {
542 (PathSource::Trait, true) => "E0404",
543 (PathSource::Trait, false) => "E0405",
544 (PathSource::Type, true) => "E0573",
545 (PathSource::Type, false) => "E0412",
546 (PathSource::Struct, true) => "E0574",
547 (PathSource::Struct, false) => "E0422",
548 (PathSource::Expr(..), true) => "E0423",
549 (PathSource::Expr(..), false) => "E0425",
550 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
551 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
552 (PathSource::TraitItem(..), true) => "E0575",
553 (PathSource::TraitItem(..), false) => "E0576",
554 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
555 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
560 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
567 #[derive(Clone, Default, Debug)]
568 pub struct PerNS<T> {
574 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
576 fn index(&self, ns: Namespace) -> &T {
578 ValueNS => &self.value_ns,
579 TypeNS => &self.type_ns,
580 MacroNS => self.macro_ns.as_ref().unwrap(),
585 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
586 fn index_mut(&mut self, ns: Namespace) -> &mut T {
588 ValueNS => &mut self.value_ns,
589 TypeNS => &mut self.type_ns,
590 MacroNS => self.macro_ns.as_mut().unwrap(),
595 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
596 fn visit_item(&mut self, item: &'tcx Item) {
597 self.resolve_item(item);
599 fn visit_arm(&mut self, arm: &'tcx Arm) {
600 self.resolve_arm(arm);
602 fn visit_block(&mut self, block: &'tcx Block) {
603 self.resolve_block(block);
605 fn visit_expr(&mut self, expr: &'tcx Expr) {
606 self.resolve_expr(expr, None);
608 fn visit_local(&mut self, local: &'tcx Local) {
609 self.resolve_local(local);
611 fn visit_ty(&mut self, ty: &'tcx Ty) {
612 if let TyKind::Path(ref qself, ref path) = ty.node {
613 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
614 } else if let TyKind::ImplicitSelf = ty.node {
615 let self_ty = keywords::SelfType.ident();
616 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.span))
617 .map_or(Def::Err, |d| d.def());
618 self.record_def(ty.id, PathResolution::new(def));
619 } else if let TyKind::Array(ref element, ref length) = ty.node {
620 self.visit_ty(element);
621 self.with_constant_rib(|this| {
622 this.visit_expr(length);
626 visit::walk_ty(self, ty);
628 fn visit_poly_trait_ref(&mut self,
629 tref: &'tcx ast::PolyTraitRef,
630 m: &'tcx ast::TraitBoundModifier) {
631 self.smart_resolve_path(tref.trait_ref.ref_id, None,
632 &tref.trait_ref.path, PathSource::Trait);
633 visit::walk_poly_trait_ref(self, tref, m);
635 fn visit_variant(&mut self,
636 variant: &'tcx ast::Variant,
637 generics: &'tcx Generics,
638 item_id: ast::NodeId) {
639 if let Some(ref dis_expr) = variant.node.disr_expr {
640 // resolve the discriminator expr as a constant
641 self.with_constant_rib(|this| {
642 this.visit_expr(dis_expr);
646 // `visit::walk_variant` without the discriminant expression.
647 self.visit_variant_data(&variant.node.data,
653 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
654 let type_parameters = match foreign_item.node {
655 ForeignItemKind::Fn(_, ref generics) => {
656 HasTypeParameters(generics, ItemRibKind)
658 ForeignItemKind::Static(..) => NoTypeParameters,
660 self.with_type_parameter_rib(type_parameters, |this| {
661 visit::walk_foreign_item(this, foreign_item);
664 fn visit_fn(&mut self,
665 function_kind: FnKind<'tcx>,
666 declaration: &'tcx FnDecl,
669 let rib_kind = match function_kind {
670 FnKind::ItemFn(_, generics, ..) => {
671 self.visit_generics(generics);
674 FnKind::Method(_, sig, _, _) => {
675 self.visit_generics(&sig.generics);
676 MethodRibKind(!sig.decl.has_self())
678 FnKind::Closure(_) => ClosureRibKind(node_id),
681 // Create a value rib for the function.
682 self.ribs[ValueNS].push(Rib::new(rib_kind));
684 // Create a label rib for the function.
685 self.label_ribs.push(Rib::new(rib_kind));
687 // Add each argument to the rib.
688 let mut bindings_list = FxHashMap();
689 for argument in &declaration.inputs {
690 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
692 self.visit_ty(&argument.ty);
694 debug!("(resolving function) recorded argument");
696 visit::walk_fn_ret_ty(self, &declaration.output);
698 // Resolve the function body.
699 match function_kind {
700 FnKind::ItemFn(.., body) |
701 FnKind::Method(.., body) => {
702 self.visit_block(body);
704 FnKind::Closure(body) => {
705 self.visit_expr(body);
709 debug!("(resolving function) leaving function");
711 self.label_ribs.pop();
712 self.ribs[ValueNS].pop();
714 fn visit_generics(&mut self, generics: &'tcx Generics) {
715 // For type parameter defaults, we have to ban access
716 // to following type parameters, as the Substs can only
717 // provide previous type parameters as they're built.
718 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
719 default_ban_rib.bindings.extend(generics.ty_params.iter()
720 .skip_while(|p| p.default.is_none())
721 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
723 for param in &generics.ty_params {
724 for bound in ¶m.bounds {
725 self.visit_ty_param_bound(bound);
728 if let Some(ref ty) = param.default {
729 self.ribs[TypeNS].push(default_ban_rib);
731 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
734 // Allow all following defaults to refer to this type parameter.
735 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
737 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
738 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
742 pub type ErrorMessage = Option<(Span, String)>;
744 #[derive(Copy, Clone)]
745 enum TypeParameters<'a, 'b> {
747 HasTypeParameters(// Type parameters.
750 // The kind of the rib used for type parameters.
754 // The rib kind controls the translation of local
755 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
756 #[derive(Copy, Clone, Debug)]
758 // No translation needs to be applied.
761 // We passed through a closure scope at the given node ID.
762 // Translate upvars as appropriate.
763 ClosureRibKind(NodeId /* func id */),
765 // We passed through an impl or trait and are now in one of its
766 // methods. Allow references to ty params that impl or trait
767 // binds. Disallow any other upvars (including other ty params that are
770 // The boolean value represents the fact that this method is static or not.
773 // We passed through an item scope. Disallow upvars.
776 // We're in a constant item. Can't refer to dynamic stuff.
779 // We passed through a module.
780 ModuleRibKind(Module<'a>),
782 // We passed through a `macro_rules!` statement
783 MacroDefinition(DefId),
785 // All bindings in this rib are type parameters that can't be used
786 // from the default of a type parameter because they're not declared
787 // before said type parameter. Also see the `visit_generics` override.
788 ForwardTyParamBanRibKind,
794 bindings: FxHashMap<Ident, Def>,
799 fn new(kind: RibKind<'a>) -> Rib<'a> {
801 bindings: FxHashMap(),
807 enum LexicalScopeBinding<'a> {
808 Item(&'a NameBinding<'a>),
812 impl<'a> LexicalScopeBinding<'a> {
813 fn item(self) -> Option<&'a NameBinding<'a>> {
815 LexicalScopeBinding::Item(binding) => Some(binding),
820 fn def(self) -> Def {
822 LexicalScopeBinding::Item(binding) => binding.def(),
823 LexicalScopeBinding::Def(def) => def,
829 enum PathResult<'a> {
831 NonModule(PathResolution),
833 Failed(String, bool /* is the error from the last segment? */),
841 /// One node in the tree of modules.
842 pub struct ModuleData<'a> {
843 parent: Option<Module<'a>>,
846 // The def id of the closest normal module (`mod`) ancestor (including this module).
847 normal_ancestor_id: DefId,
849 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
850 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
851 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
853 // Macro invocations that can expand into items in this module.
854 unresolved_invocations: RefCell<FxHashSet<Mark>>,
856 no_implicit_prelude: bool,
858 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
859 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
861 // Used to memoize the traits in this module for faster searches through all traits in scope.
862 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
864 // Whether this module is populated. If not populated, any attempt to
865 // access the children must be preceded with a
866 // `populate_module_if_necessary` call.
867 populated: Cell<bool>,
870 pub type Module<'a> = &'a ModuleData<'a>;
872 impl<'a> ModuleData<'a> {
873 fn new(parent: Option<Module<'a>>, kind: ModuleKind, normal_ancestor_id: DefId) -> Self {
877 normal_ancestor_id: normal_ancestor_id,
878 resolutions: RefCell::new(FxHashMap()),
879 legacy_macro_resolutions: RefCell::new(Vec::new()),
880 macro_resolutions: RefCell::new(Vec::new()),
881 unresolved_invocations: RefCell::new(FxHashSet()),
882 no_implicit_prelude: false,
883 glob_importers: RefCell::new(Vec::new()),
884 globs: RefCell::new((Vec::new())),
885 traits: RefCell::new(None),
886 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 // Maps the `Mark` of an expansion to its containing module or block.
1191 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1193 // Avoid duplicated errors for "name already defined".
1194 name_already_seen: FxHashMap<Name, Span>,
1196 // If `#![feature(proc_macro)]` is set
1197 proc_macro_enabled: bool,
1199 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1200 warned_proc_macros: FxHashSet<Name>,
1202 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1204 // This table maps struct IDs into struct constructor IDs,
1205 // it's not used during normal resolution, only for better error reporting.
1206 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1209 pub struct ResolverArenas<'a> {
1210 modules: arena::TypedArena<ModuleData<'a>>,
1211 local_modules: RefCell<Vec<Module<'a>>>,
1212 name_bindings: arena::TypedArena<NameBinding<'a>>,
1213 import_directives: arena::TypedArena<ImportDirective<'a>>,
1214 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1215 invocation_data: arena::TypedArena<InvocationData<'a>>,
1216 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1219 impl<'a> ResolverArenas<'a> {
1220 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1221 let module = self.modules.alloc(module);
1222 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1223 self.local_modules.borrow_mut().push(module);
1227 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1228 self.local_modules.borrow()
1230 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1231 self.name_bindings.alloc(name_binding)
1233 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1234 -> &'a ImportDirective {
1235 self.import_directives.alloc(import_directive)
1237 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1238 self.name_resolutions.alloc(Default::default())
1240 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1241 -> &'a InvocationData<'a> {
1242 self.invocation_data.alloc(expansion_data)
1244 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1245 self.legacy_bindings.alloc(binding)
1249 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1250 fn parent(self, id: DefId) -> Option<DefId> {
1252 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1253 _ => self.session.cstore.def_key(id).parent,
1254 }.map(|index| DefId { index: index, ..id })
1258 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1259 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1260 let namespace = if is_value { ValueNS } else { TypeNS };
1261 let hir::Path { ref segments, span, ref mut def } = *path;
1262 let path: Vec<_> = segments.iter().map(|seg| Ident::with_empty_ctxt(seg.name)).collect();
1263 match self.resolve_path(&path, Some(namespace), Some(span)) {
1264 PathResult::Module(module) => *def = module.def().unwrap(),
1265 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1266 *def = path_res.base_def(),
1267 PathResult::NonModule(..) => match self.resolve_path(&path, None, Some(span)) {
1268 PathResult::Failed(msg, _) => {
1269 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1273 PathResult::Indeterminate => unreachable!(),
1274 PathResult::Failed(msg, _) => {
1275 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1280 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1281 self.def_map.get(&id).cloned()
1284 fn definitions(&mut self) -> &mut Definitions {
1285 &mut self.definitions
1289 impl<'a> Resolver<'a> {
1290 pub fn new(session: &'a Session,
1292 make_glob_map: MakeGlobMap,
1293 crate_loader: &'a mut CrateLoader,
1294 arenas: &'a ResolverArenas<'a>)
1296 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1297 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1298 let graph_root = arenas.alloc_module(ModuleData {
1299 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1300 ..ModuleData::new(None, root_module_kind, root_def_id)
1302 let mut module_map = FxHashMap();
1303 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1305 let mut definitions = Definitions::new();
1306 DefCollector::new(&mut definitions).collect_root();
1308 let mut invocations = FxHashMap();
1309 invocations.insert(Mark::root(),
1310 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1312 let features = session.features.borrow();
1314 let mut macro_defs = FxHashMap();
1315 macro_defs.insert(Mark::root(), root_def_id);
1320 definitions: definitions,
1322 // The outermost module has def ID 0; this is not reflected in the
1324 graph_root: graph_root,
1327 trait_item_map: FxHashMap(),
1328 field_names: FxHashMap(),
1330 determined_imports: Vec::new(),
1331 indeterminate_imports: Vec::new(),
1333 current_module: graph_root,
1335 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1336 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1337 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1339 label_ribs: Vec::new(),
1341 current_trait_ref: None,
1342 current_self_type: None,
1344 primitive_type_table: PrimitiveTypeTable::new(),
1347 freevars: NodeMap(),
1348 freevars_seen: NodeMap(),
1349 export_map: NodeMap(),
1350 trait_map: NodeMap(),
1351 module_map: module_map,
1352 block_map: NodeMap(),
1353 extern_crate_roots: FxHashMap(),
1355 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1356 glob_map: NodeMap(),
1358 used_imports: FxHashSet(),
1359 maybe_unused_trait_imports: NodeSet(),
1361 privacy_errors: Vec::new(),
1362 ambiguity_errors: Vec::new(),
1363 gated_errors: FxHashSet(),
1364 disallowed_shadowing: Vec::new(),
1367 dummy_binding: arenas.alloc_name_binding(NameBinding {
1368 kind: NameBindingKind::Def(Def::Err),
1369 expansion: Mark::root(),
1371 vis: ty::Visibility::Public,
1374 // `#![feature(proc_macro)]` implies `#[feature(extern_macros)]`
1375 use_extern_macros: features.use_extern_macros || features.proc_macro,
1377 crate_loader: crate_loader,
1378 macro_names: FxHashSet(),
1379 global_macros: FxHashMap(),
1380 lexical_macro_resolutions: Vec::new(),
1381 macro_map: FxHashMap(),
1382 macro_exports: Vec::new(),
1383 invocations: invocations,
1384 macro_defs: macro_defs,
1385 local_macro_def_scopes: FxHashMap(),
1386 name_already_seen: FxHashMap(),
1387 whitelisted_legacy_custom_derives: Vec::new(),
1388 proc_macro_enabled: features.proc_macro,
1389 warned_proc_macros: FxHashSet(),
1390 potentially_unused_imports: Vec::new(),
1391 struct_constructors: DefIdMap(),
1392 found_unresolved_macro: false,
1396 pub fn arenas() -> ResolverArenas<'a> {
1398 modules: arena::TypedArena::new(),
1399 local_modules: RefCell::new(Vec::new()),
1400 name_bindings: arena::TypedArena::new(),
1401 import_directives: arena::TypedArena::new(),
1402 name_resolutions: arena::TypedArena::new(),
1403 invocation_data: arena::TypedArena::new(),
1404 legacy_bindings: arena::TypedArena::new(),
1408 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1410 type_ns: f(self, TypeNS),
1411 value_ns: f(self, ValueNS),
1412 macro_ns: match self.use_extern_macros {
1413 true => Some(f(self, MacroNS)),
1419 /// Entry point to crate resolution.
1420 pub fn resolve_crate(&mut self, krate: &Crate) {
1421 ImportResolver { resolver: self }.finalize_imports();
1422 self.current_module = self.graph_root;
1423 self.finalize_current_module_macro_resolutions();
1424 visit::walk_crate(self, krate);
1426 check_unused::check_crate(self, krate);
1427 self.report_errors();
1428 self.crate_loader.postprocess(krate);
1431 fn new_module(&self, parent: Module<'a>, kind: ModuleKind, normal_ancestor_id: DefId)
1433 self.arenas.alloc_module(ModuleData::new(Some(parent), kind, normal_ancestor_id))
1436 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1437 -> bool /* true if an error was reported */ {
1438 match binding.kind {
1439 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1442 directive.used.set(true);
1443 if legacy_self_import {
1444 self.warn_legacy_self_import(directive);
1447 self.used_imports.insert((directive.id, ns));
1448 self.add_to_glob_map(directive.id, ident);
1449 self.record_use(ident, ns, binding, span)
1451 NameBindingKind::Import { .. } => false,
1452 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1453 self.ambiguity_errors.push(AmbiguityError {
1454 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy: legacy,
1457 self.record_use(ident, ns, b1, span);
1465 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1466 if self.make_glob_map {
1467 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1471 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1472 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1473 /// `ident` in the first scope that defines it (or None if no scopes define it).
1475 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1476 /// the items are defined in the block. For example,
1479 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1482 /// g(); // This resolves to the local variable `g` since it shadows the item.
1486 /// Invariant: This must only be called during main resolution, not during
1487 /// import resolution.
1488 fn resolve_ident_in_lexical_scope(&mut self,
1491 record_used: Option<Span>)
1492 -> Option<LexicalScopeBinding<'a>> {
1494 ident = ident.unhygienize();
1497 // Walk backwards up the ribs in scope.
1498 for i in (0 .. self.ribs[ns].len()).rev() {
1499 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1500 // The ident resolves to a type parameter or local variable.
1501 return Some(LexicalScopeBinding::Def(
1502 self.adjust_local_def(ns, i, def, record_used)
1506 if let ModuleRibKind(module) = self.ribs[ns][i].kind {
1507 let item = self.resolve_ident_in_module(module, ident, ns, false, record_used);
1508 if let Ok(binding) = item {
1509 // The ident resolves to an item.
1510 return Some(LexicalScopeBinding::Item(binding));
1513 if let ModuleKind::Block(..) = module.kind { // We can see through blocks
1514 } else if !module.no_implicit_prelude {
1515 return self.prelude.and_then(|prelude| {
1516 self.resolve_ident_in_module(prelude, ident, ns, false, None).ok()
1517 }).map(LexicalScopeBinding::Item)
1523 if let MacroDefinition(def) = self.ribs[ns][i].kind {
1524 // If an invocation of this macro created `ident`, give up on `ident`
1525 // and switch to `ident`'s source from the macro definition.
1526 let ctxt_data = ident.ctxt.data();
1527 if def == self.macro_defs[&ctxt_data.outer_mark] {
1528 ident.ctxt = ctxt_data.prev_ctxt;
1536 fn resolve_crate_var(&mut self, crate_var_ctxt: SyntaxContext) -> Module<'a> {
1537 let mut ctxt_data = crate_var_ctxt.data();
1538 while ctxt_data.prev_ctxt != SyntaxContext::empty() {
1539 ctxt_data = ctxt_data.prev_ctxt.data();
1541 let module = self.macro_def_scope(ctxt_data.outer_mark);
1542 if module.is_local() { self.graph_root } else { module }
1547 // We maintain a list of value ribs and type ribs.
1549 // Simultaneously, we keep track of the current position in the module
1550 // graph in the `current_module` pointer. When we go to resolve a name in
1551 // the value or type namespaces, we first look through all the ribs and
1552 // then query the module graph. When we resolve a name in the module
1553 // namespace, we can skip all the ribs (since nested modules are not
1554 // allowed within blocks in Rust) and jump straight to the current module
1557 // Named implementations are handled separately. When we find a method
1558 // call, we consult the module node to find all of the implementations in
1559 // scope. This information is lazily cached in the module node. We then
1560 // generate a fake "implementation scope" containing all the
1561 // implementations thus found, for compatibility with old resolve pass.
1563 fn with_scope<F>(&mut self, id: NodeId, f: F)
1564 where F: FnOnce(&mut Resolver)
1566 let id = self.definitions.local_def_id(id);
1567 let module = self.module_map.get(&id).cloned(); // clones a reference
1568 if let Some(module) = module {
1569 // Move down in the graph.
1570 let orig_module = replace(&mut self.current_module, module);
1571 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1572 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1574 self.finalize_current_module_macro_resolutions();
1577 self.current_module = orig_module;
1578 self.ribs[ValueNS].pop();
1579 self.ribs[TypeNS].pop();
1585 /// Searches the current set of local scopes for labels.
1586 /// Stops after meeting a closure.
1587 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1588 for rib in self.label_ribs.iter().rev() {
1593 MacroDefinition(def) => {
1594 // If an invocation of this macro created `ident`, give up on `ident`
1595 // and switch to `ident`'s source from the macro definition.
1596 let ctxt_data = ident.ctxt.data();
1597 if def == self.macro_defs[&ctxt_data.outer_mark] {
1598 ident.ctxt = ctxt_data.prev_ctxt;
1602 // Do not resolve labels across function boundary
1606 let result = rib.bindings.get(&ident).cloned();
1607 if result.is_some() {
1614 fn resolve_item(&mut self, item: &Item) {
1615 let name = item.ident.name;
1617 debug!("(resolving item) resolving {}", name);
1619 self.check_proc_macro_attrs(&item.attrs);
1622 ItemKind::Enum(_, ref generics) |
1623 ItemKind::Ty(_, ref generics) |
1624 ItemKind::Struct(_, ref generics) |
1625 ItemKind::Union(_, ref generics) |
1626 ItemKind::Fn(.., ref generics, _) => {
1627 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1628 |this| visit::walk_item(this, item));
1631 ItemKind::DefaultImpl(_, ref trait_ref) => {
1632 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1633 // Resolve type arguments in trait path
1634 visit::walk_trait_ref(this, trait_ref);
1637 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1638 self.resolve_implementation(generics,
1644 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1645 // Create a new rib for the trait-wide type parameters.
1646 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1647 let local_def_id = this.definitions.local_def_id(item.id);
1648 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1649 this.visit_generics(generics);
1650 walk_list!(this, visit_ty_param_bound, bounds);
1652 for trait_item in trait_items {
1653 this.check_proc_macro_attrs(&trait_item.attrs);
1655 match trait_item.node {
1656 TraitItemKind::Const(_, ref default) => {
1657 // Only impose the restrictions of
1658 // ConstRibKind if there's an actual constant
1659 // expression in a provided default.
1660 if default.is_some() {
1661 this.with_constant_rib(|this| {
1662 visit::walk_trait_item(this, trait_item)
1665 visit::walk_trait_item(this, trait_item)
1668 TraitItemKind::Method(ref sig, _) => {
1669 let type_parameters =
1670 HasTypeParameters(&sig.generics,
1671 MethodRibKind(!sig.decl.has_self()));
1672 this.with_type_parameter_rib(type_parameters, |this| {
1673 visit::walk_trait_item(this, trait_item)
1676 TraitItemKind::Type(..) => {
1677 this.with_type_parameter_rib(NoTypeParameters, |this| {
1678 visit::walk_trait_item(this, trait_item)
1681 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1688 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1689 self.with_scope(item.id, |this| {
1690 visit::walk_item(this, item);
1694 ItemKind::Const(..) | ItemKind::Static(..) => {
1695 self.with_constant_rib(|this| {
1696 visit::walk_item(this, item);
1700 ItemKind::Use(ref view_path) => {
1701 match view_path.node {
1702 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1703 // Resolve prefix of an import with empty braces (issue #28388).
1704 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1710 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) => {
1711 // do nothing, these are just around to be encoded
1714 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1718 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1719 where F: FnOnce(&mut Resolver)
1721 match type_parameters {
1722 HasTypeParameters(generics, rib_kind) => {
1723 let mut function_type_rib = Rib::new(rib_kind);
1724 let mut seen_bindings = FxHashMap();
1725 for type_parameter in &generics.ty_params {
1726 let name = type_parameter.ident.name;
1727 debug!("with_type_parameter_rib: {}", type_parameter.id);
1729 if seen_bindings.contains_key(&name) {
1730 let span = seen_bindings.get(&name).unwrap();
1732 type_parameter.span,
1733 ResolutionError::NameAlreadyUsedInTypeParameterList(name,
1736 seen_bindings.entry(name).or_insert(type_parameter.span);
1738 // plain insert (no renaming)
1739 let def_id = self.definitions.local_def_id(type_parameter.id);
1740 let def = Def::TyParam(def_id);
1741 function_type_rib.bindings.insert(Ident::with_empty_ctxt(name), def);
1742 self.record_def(type_parameter.id, PathResolution::new(def));
1744 self.ribs[TypeNS].push(function_type_rib);
1747 NoTypeParameters => {
1754 if let HasTypeParameters(..) = type_parameters {
1755 self.ribs[TypeNS].pop();
1759 fn with_label_rib<F>(&mut self, f: F)
1760 where F: FnOnce(&mut Resolver)
1762 self.label_ribs.push(Rib::new(NormalRibKind));
1764 self.label_ribs.pop();
1767 fn with_constant_rib<F>(&mut self, f: F)
1768 where F: FnOnce(&mut Resolver)
1770 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1771 self.ribs[TypeNS].push(Rib::new(ConstantItemRibKind));
1773 self.ribs[TypeNS].pop();
1774 self.ribs[ValueNS].pop();
1777 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1778 where F: FnOnce(&mut Resolver) -> T
1780 // Handle nested impls (inside fn bodies)
1781 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1782 let result = f(self);
1783 self.current_self_type = previous_value;
1787 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1788 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1790 let mut new_val = None;
1791 let mut new_id = None;
1792 if let Some(trait_ref) = opt_trait_ref {
1793 let def = self.smart_resolve_path(trait_ref.ref_id, None,
1794 &trait_ref.path, PathSource::Trait).base_def();
1795 if def != Def::Err {
1796 new_val = Some((def.def_id(), trait_ref.clone()));
1797 new_id = Some(def.def_id());
1800 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
1801 let result = f(self, new_id);
1802 self.current_trait_ref = original_trait_ref;
1806 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
1807 where F: FnOnce(&mut Resolver)
1809 let mut self_type_rib = Rib::new(NormalRibKind);
1811 // plain insert (no renaming, types are not currently hygienic....)
1812 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
1813 self.ribs[TypeNS].push(self_type_rib);
1815 self.ribs[TypeNS].pop();
1818 fn resolve_implementation(&mut self,
1819 generics: &Generics,
1820 opt_trait_reference: &Option<TraitRef>,
1823 impl_items: &[ImplItem]) {
1824 // If applicable, create a rib for the type parameters.
1825 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1826 // Dummy self type for better errors if `Self` is used in the trait path.
1827 this.with_self_rib(Def::SelfTy(None, None), |this| {
1828 // Resolve the trait reference, if necessary.
1829 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
1830 let item_def_id = this.definitions.local_def_id(item_id);
1831 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
1832 if let Some(trait_ref) = opt_trait_reference.as_ref() {
1833 // Resolve type arguments in trait path
1834 visit::walk_trait_ref(this, trait_ref);
1836 // Resolve the self type.
1837 this.visit_ty(self_type);
1838 // Resolve the type parameters.
1839 this.visit_generics(generics);
1840 this.with_current_self_type(self_type, |this| {
1841 for impl_item in impl_items {
1842 this.check_proc_macro_attrs(&impl_item.attrs);
1843 this.resolve_visibility(&impl_item.vis);
1844 match impl_item.node {
1845 ImplItemKind::Const(..) => {
1846 // If this is a trait impl, ensure the const
1848 this.check_trait_item(impl_item.ident.name,
1851 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
1852 visit::walk_impl_item(this, impl_item);
1854 ImplItemKind::Method(ref sig, _) => {
1855 // If this is a trait impl, ensure the method
1857 this.check_trait_item(impl_item.ident.name,
1860 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
1862 // We also need a new scope for the method-
1863 // specific type parameters.
1864 let type_parameters =
1865 HasTypeParameters(&sig.generics,
1866 MethodRibKind(!sig.decl.has_self()));
1867 this.with_type_parameter_rib(type_parameters, |this| {
1868 visit::walk_impl_item(this, impl_item);
1871 ImplItemKind::Type(ref ty) => {
1872 // If this is a trait impl, ensure the type
1874 this.check_trait_item(impl_item.ident.name,
1877 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
1881 ImplItemKind::Macro(_) =>
1882 panic!("unexpanded macro in resolve!"),
1892 fn check_trait_item<F>(&self, name: Name, ns: Namespace, span: Span, err: F)
1893 where F: FnOnce(Name, &str) -> ResolutionError
1895 // If there is a TraitRef in scope for an impl, then the method must be in the
1897 if let Some((did, ref trait_ref)) = self.current_trait_ref {
1898 if !self.trait_item_map.contains_key(&(did, name, ns)) {
1899 let path_str = path_names_to_string(&trait_ref.path);
1900 resolve_error(self, span, err(name, &path_str));
1905 fn resolve_local(&mut self, local: &Local) {
1906 // Resolve the type.
1907 walk_list!(self, visit_ty, &local.ty);
1909 // Resolve the initializer.
1910 walk_list!(self, visit_expr, &local.init);
1912 // Resolve the pattern.
1913 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
1916 // build a map from pattern identifiers to binding-info's.
1917 // this is done hygienically. This could arise for a macro
1918 // that expands into an or-pattern where one 'x' was from the
1919 // user and one 'x' came from the macro.
1920 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
1921 let mut binding_map = FxHashMap();
1923 pat.walk(&mut |pat| {
1924 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
1925 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
1926 Some(Def::Local(..)) => true,
1929 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
1930 binding_map.insert(ident.node, binding_info);
1939 // check that all of the arms in an or-pattern have exactly the
1940 // same set of bindings, with the same binding modes for each.
1941 fn check_consistent_bindings(&mut self, arm: &Arm) {
1942 if arm.pats.is_empty() {
1946 let mut missing_vars = FxHashMap();
1947 let mut inconsistent_vars = FxHashMap();
1948 for (i, p) in arm.pats.iter().enumerate() {
1949 let map_i = self.binding_mode_map(&p);
1951 for (j, q) in arm.pats.iter().enumerate() {
1956 let map_j = self.binding_mode_map(&q);
1957 for (&key, &binding_i) in &map_i {
1958 if map_j.len() == 0 { // Account for missing bindings when
1959 let binding_error = missing_vars // map_j has none.
1961 .or_insert(BindingError {
1963 origin: BTreeSet::new(),
1964 target: BTreeSet::new(),
1966 binding_error.origin.insert(binding_i.span);
1967 binding_error.target.insert(q.span);
1969 for (&key_j, &binding_j) in &map_j {
1970 match map_i.get(&key_j) {
1971 None => { // missing binding
1972 let binding_error = missing_vars
1974 .or_insert(BindingError {
1976 origin: BTreeSet::new(),
1977 target: BTreeSet::new(),
1979 binding_error.origin.insert(binding_j.span);
1980 binding_error.target.insert(p.span);
1982 Some(binding_i) => { // check consistent binding
1983 if binding_i.binding_mode != binding_j.binding_mode {
1986 .or_insert((binding_j.span, binding_i.span));
1994 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
1995 missing_vars.sort();
1996 for (_, v) in missing_vars {
1998 *v.origin.iter().next().unwrap(),
1999 ResolutionError::VariableNotBoundInPattern(v));
2001 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2002 inconsistent_vars.sort();
2003 for (name, v) in inconsistent_vars {
2004 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2008 fn resolve_arm(&mut self, arm: &Arm) {
2009 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2011 let mut bindings_list = FxHashMap();
2012 for pattern in &arm.pats {
2013 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2016 // This has to happen *after* we determine which
2017 // pat_idents are variants
2018 self.check_consistent_bindings(arm);
2020 walk_list!(self, visit_expr, &arm.guard);
2021 self.visit_expr(&arm.body);
2023 self.ribs[ValueNS].pop();
2026 fn resolve_block(&mut self, block: &Block) {
2027 debug!("(resolving block) entering block");
2028 // Move down in the graph, if there's an anonymous module rooted here.
2029 let orig_module = self.current_module;
2030 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2032 let mut num_macro_definition_ribs = 0;
2033 if let Some(anonymous_module) = anonymous_module {
2034 debug!("(resolving block) found anonymous module, moving down");
2035 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2036 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2037 self.current_module = anonymous_module;
2038 self.finalize_current_module_macro_resolutions();
2040 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2043 // Descend into the block.
2044 for stmt in &block.stmts {
2045 if let ast::StmtKind::Item(ref item) = stmt.node {
2046 if let ast::ItemKind::MacroDef(..) = item.node {
2047 num_macro_definition_ribs += 1;
2048 let def = self.definitions.local_def_id(item.id);
2049 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2050 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2054 self.visit_stmt(stmt);
2058 self.current_module = orig_module;
2059 for _ in 0 .. num_macro_definition_ribs {
2060 self.ribs[ValueNS].pop();
2061 self.label_ribs.pop();
2063 self.ribs[ValueNS].pop();
2064 if let Some(_) = anonymous_module {
2065 self.ribs[TypeNS].pop();
2067 debug!("(resolving block) leaving block");
2070 fn fresh_binding(&mut self,
2071 ident: &SpannedIdent,
2073 outer_pat_id: NodeId,
2074 pat_src: PatternSource,
2075 bindings: &mut FxHashMap<Ident, NodeId>)
2077 // Add the binding to the local ribs, if it
2078 // doesn't already exist in the bindings map. (We
2079 // must not add it if it's in the bindings map
2080 // because that breaks the assumptions later
2081 // passes make about or-patterns.)
2082 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2083 match bindings.get(&ident.node).cloned() {
2084 Some(id) if id == outer_pat_id => {
2085 // `Variant(a, a)`, error
2089 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2090 &ident.node.name.as_str())
2093 Some(..) if pat_src == PatternSource::FnParam => {
2094 // `fn f(a: u8, a: u8)`, error
2098 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2099 &ident.node.name.as_str())
2102 Some(..) if pat_src == PatternSource::Match => {
2103 // `Variant1(a) | Variant2(a)`, ok
2104 // Reuse definition from the first `a`.
2105 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2108 span_bug!(ident.span, "two bindings with the same name from \
2109 unexpected pattern source {:?}", pat_src);
2112 // A completely fresh binding, add to the lists if it's valid.
2113 if ident.node.name != keywords::Invalid.name() {
2114 bindings.insert(ident.node, outer_pat_id);
2115 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2120 PathResolution::new(def)
2123 fn resolve_pattern(&mut self,
2125 pat_src: PatternSource,
2126 // Maps idents to the node ID for the
2127 // outermost pattern that binds them.
2128 bindings: &mut FxHashMap<Ident, NodeId>) {
2129 // Visit all direct subpatterns of this pattern.
2130 let outer_pat_id = pat.id;
2131 pat.walk(&mut |pat| {
2133 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2134 // First try to resolve the identifier as some existing
2135 // entity, then fall back to a fresh binding.
2136 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS, None)
2137 .and_then(LexicalScopeBinding::item);
2138 let resolution = binding.map(NameBinding::def).and_then(|def| {
2139 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2140 bmode != BindingMode::ByValue(Mutability::Immutable);
2142 Def::StructCtor(_, CtorKind::Const) |
2143 Def::VariantCtor(_, CtorKind::Const) |
2144 Def::Const(..) if !always_binding => {
2145 // A unit struct/variant or constant pattern.
2146 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2147 Some(PathResolution::new(def))
2149 Def::StructCtor(..) | Def::VariantCtor(..) |
2150 Def::Const(..) | Def::Static(..) => {
2151 // A fresh binding that shadows something unacceptable.
2155 ResolutionError::BindingShadowsSomethingUnacceptable(
2156 pat_src.descr(), ident.node.name, binding.unwrap())
2160 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2161 // These entities are explicitly allowed
2162 // to be shadowed by fresh bindings.
2166 span_bug!(ident.span, "unexpected definition for an \
2167 identifier in pattern: {:?}", def);
2170 }).unwrap_or_else(|| {
2171 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2174 self.record_def(pat.id, resolution);
2177 PatKind::TupleStruct(ref path, ..) => {
2178 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2181 PatKind::Path(ref qself, ref path) => {
2182 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2185 PatKind::Struct(ref path, ..) => {
2186 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2194 visit::walk_pat(self, pat);
2197 // High-level and context dependent path resolution routine.
2198 // Resolves the path and records the resolution into definition map.
2199 // If resolution fails tries several techniques to find likely
2200 // resolution candidates, suggest imports or other help, and report
2201 // errors in user friendly way.
2202 fn smart_resolve_path(&mut self,
2204 qself: Option<&QSelf>,
2208 let segments = &path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>();
2209 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2210 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2213 fn smart_resolve_path_fragment(&mut self,
2215 qself: Option<&QSelf>,
2221 let ns = source.namespace();
2222 let is_expected = &|def| source.is_expected(def);
2224 // Base error is amended with one short label and possibly some longer helps/notes.
2225 let report_errors = |this: &mut Self, def: Option<Def>| {
2226 // Make the base error.
2227 let expected = source.descr_expected();
2228 let path_str = names_to_string(path);
2229 let code = source.error_code(def.is_some());
2230 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2231 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2232 format!("not a {}", expected), span)
2234 let item_str = path[path.len() - 1];
2235 let (mod_prefix, mod_str) = if path.len() == 1 {
2236 (format!(""), format!("this scope"))
2237 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2238 (format!(""), format!("the crate root"))
2240 let mod_path = &path[..path.len() - 1];
2241 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), None) {
2242 PathResult::Module(module) => module.def(),
2244 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2245 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2247 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2248 format!("not found in {}", mod_str), ident_span)
2250 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2252 // Emit special messages for unresolved `Self` and `self`.
2253 if is_self_type(path, ns) {
2254 __diagnostic_used!(E0411);
2255 err.code("E0411".into());
2256 err.span_label(span, &format!("`Self` is only available in traits and impls"));
2259 if is_self_value(path, ns) {
2260 __diagnostic_used!(E0424);
2261 err.code("E0424".into());
2262 err.span_label(span, &format!("`self` value is only available in \
2263 methods with `self` parameter"));
2267 // Try to lookup the name in more relaxed fashion for better error reporting.
2268 let name = path.last().unwrap().name;
2269 let candidates = this.lookup_import_candidates(name, ns, is_expected);
2270 if !candidates.is_empty() {
2271 // Report import candidates as help and proceed searching for labels.
2272 show_candidates(&mut err, &candidates, def.is_some());
2274 if path.len() == 1 && this.self_type_is_available() {
2275 if let Some(candidate) = this.lookup_assoc_candidate(name, ns, is_expected) {
2276 let self_is_available = this.self_value_is_available(path[0].ctxt);
2278 AssocSuggestion::Field => {
2279 err.span_label(span, &format!("did you mean `self.{}`?", path_str));
2280 if !self_is_available {
2281 err.span_label(span, &format!("`self` value is only available in \
2282 methods with `self` parameter"));
2285 AssocSuggestion::MethodWithSelf if self_is_available => {
2286 err.span_label(span, &format!("did you mean `self.{}(...)`?",
2289 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2290 err.span_label(span, &format!("did you mean `Self::{}`?", path_str));
2297 // Try context dependent help if relaxed lookup didn't work.
2298 if let Some(def) = def {
2299 match (def, source) {
2300 (Def::Macro(..), _) => {
2301 err.span_label(span, &format!("did you mean `{}!(...)`?", path_str));
2304 (Def::TyAlias(..), PathSource::Trait) => {
2305 err.span_label(span, &format!("type aliases cannot be used for traits"));
2308 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2309 ExprKind::Field(_, ident) => {
2310 err.span_label(parent.span, &format!("did you mean `{}::{}`?",
2311 path_str, ident.node));
2314 ExprKind::MethodCall(ident, ..) => {
2315 err.span_label(parent.span, &format!("did you mean `{}::{}(...)`?",
2316 path_str, ident.node));
2321 _ if ns == ValueNS && is_struct_like(def) => {
2322 if let Def::Struct(def_id) = def {
2323 if let Some((ctor_def, ctor_vis))
2324 = this.struct_constructors.get(&def_id).cloned() {
2325 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2326 err.span_label(span, &format!("constructor is not visible \
2327 here due to private fields"));
2331 err.span_label(span, &format!("did you mean `{} {{ /* fields */ }}`?",
2339 // Try Levenshtein if nothing else worked.
2340 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected) {
2341 err.span_label(ident_span, &format!("did you mean `{}`?", candidate));
2346 err.span_label(base_span, &fallback_label);
2349 let report_errors = |this: &mut Self, def: Option<Def>| {
2350 report_errors(this, def).emit();
2351 err_path_resolution()
2354 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2355 source.defer_to_typeck(),
2356 source.global_by_default()) {
2357 Some(resolution) if resolution.unresolved_segments() == 0 => {
2358 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2361 // Add a temporary hack to smooth the transition to new struct ctor
2362 // visibility rules. See #38932 for more details.
2364 if let Def::Struct(def_id) = resolution.base_def() {
2365 if let Some((ctor_def, ctor_vis))
2366 = self.struct_constructors.get(&def_id).cloned() {
2367 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2368 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2369 self.session.add_lint(lint, id, span,
2370 "private struct constructors are not usable through \
2371 reexports in outer modules".to_string());
2372 res = Some(PathResolution::new(ctor_def));
2377 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2380 Some(resolution) if source.defer_to_typeck() => {
2381 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2382 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2383 // it needs to be added to the trait map.
2385 let item_name = path.last().unwrap().name;
2386 let traits = self.get_traits_containing_item(item_name, ns);
2387 self.trait_map.insert(id, traits);
2391 _ => report_errors(self, None)
2394 if let PathSource::TraitItem(..) = source {} else {
2395 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2396 self.record_def(id, resolution);
2401 fn self_type_is_available(&mut self) -> bool {
2402 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(), TypeNS, None);
2403 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2406 fn self_value_is_available(&mut self, ctxt: SyntaxContext) -> bool {
2407 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2408 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None);
2409 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2412 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2413 fn resolve_qpath_anywhere(&mut self,
2415 qself: Option<&QSelf>,
2417 primary_ns: Namespace,
2419 defer_to_typeck: bool,
2420 global_by_default: bool)
2421 -> Option<PathResolution> {
2422 let mut fin_res = None;
2423 // FIXME: can't resolve paths in macro namespace yet, macros are
2424 // processed by the little special hack below.
2425 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2426 if i == 0 || ns != primary_ns {
2427 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2428 // If defer_to_typeck, then resolution > no resolution,
2429 // otherwise full resolution > partial resolution > no resolution.
2430 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2432 res => if fin_res.is_none() { fin_res = res },
2436 let is_global = self.global_macros.get(&path[0].name).cloned()
2437 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2438 if primary_ns != MacroNS && (is_global || self.macro_names.contains(&path[0].name)) {
2439 // Return some dummy definition, it's enough for error reporting.
2441 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2447 /// Handles paths that may refer to associated items.
2448 fn resolve_qpath(&mut self,
2450 qself: Option<&QSelf>,
2454 global_by_default: bool)
2455 -> Option<PathResolution> {
2456 if let Some(qself) = qself {
2457 if qself.position == 0 {
2458 // FIXME: Create some fake resolution that can't possibly be a type.
2459 return Some(PathResolution::with_unresolved_segments(
2460 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2463 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2464 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2465 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2466 span, span, PathSource::TraitItem(ns));
2467 return Some(PathResolution::with_unresolved_segments(
2468 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2472 let result = match self.resolve_path(&path, Some(ns), Some(span)) {
2473 PathResult::NonModule(path_res) => path_res,
2474 PathResult::Module(module) if !module.is_normal() => {
2475 PathResolution::new(module.def().unwrap())
2477 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2478 // don't report an error right away, but try to fallback to a primitive type.
2479 // So, we are still able to successfully resolve something like
2481 // use std::u8; // bring module u8 in scope
2482 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2483 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2484 // // not to non-existent std::u8::max_value
2487 // Such behavior is required for backward compatibility.
2488 // The same fallback is used when `a` resolves to nothing.
2489 PathResult::Module(..) | PathResult::Failed(..)
2490 if (ns == TypeNS || path.len() > 1) &&
2491 self.primitive_type_table.primitive_types.contains_key(&path[0].name) => {
2492 let prim = self.primitive_type_table.primitive_types[&path[0].name];
2494 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2495 if !self.session.features.borrow().i128_type {
2496 emit_feature_err(&self.session.parse_sess,
2497 "i128_type", span, GateIssue::Language,
2498 "128-bit type is unstable");
2504 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2506 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2507 PathResult::Failed(msg, false) => {
2508 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2509 err_path_resolution()
2511 PathResult::Failed(..) => return None,
2512 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2515 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2516 path[0].name != keywords::CrateRoot.name() && path[0].name != "$crate" {
2517 let unqualified_result = {
2518 match self.resolve_path(&[*path.last().unwrap()], Some(ns), None) {
2519 PathResult::NonModule(path_res) => path_res.base_def(),
2520 PathResult::Module(module) => module.def().unwrap(),
2521 _ => return Some(result),
2524 if result.base_def() == unqualified_result {
2525 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2526 self.session.add_lint(lint, id, span, "unnecessary qualification".to_string());
2533 fn resolve_path(&mut self,
2535 opt_ns: Option<Namespace>, // `None` indicates a module path
2536 record_used: Option<Span>)
2538 let mut module = None;
2539 let mut allow_super = true;
2541 for (i, &ident) in path.iter().enumerate() {
2542 let is_last = i == path.len() - 1;
2543 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2545 if i == 0 && ns == TypeNS && ident.name == keywords::SelfValue.name() {
2546 module = Some(self.module_map[&self.current_module.normal_ancestor_id]);
2548 } else if allow_super && ns == TypeNS && ident.name == keywords::Super.name() {
2549 let current_module = if i == 0 { self.current_module } else { module.unwrap() };
2550 let self_module = self.module_map[¤t_module.normal_ancestor_id];
2551 if let Some(parent) = self_module.parent {
2552 module = Some(self.module_map[&parent.normal_ancestor_id]);
2555 let msg = "There are too many initial `super`s.".to_string();
2556 return PathResult::Failed(msg, false);
2559 allow_super = false;
2561 if i == 0 && ns == TypeNS && ident.name == keywords::CrateRoot.name() {
2562 module = Some(self.graph_root);
2564 } else if i == 0 && ns == TypeNS && ident.name == "$crate" {
2565 module = Some(self.resolve_crate_var(ident.ctxt));
2569 let binding = if let Some(module) = module {
2570 self.resolve_ident_in_module(module, ident, ns, false, record_used)
2571 } else if opt_ns == Some(MacroNS) {
2572 self.resolve_lexical_macro_path_segment(ident, ns, record_used)
2573 .map(MacroBinding::binding)
2575 match self.resolve_ident_in_lexical_scope(ident, ns, record_used) {
2576 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2577 Some(LexicalScopeBinding::Def(def))
2578 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2579 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2583 _ => Err(if record_used.is_some() { Determined } else { Undetermined }),
2589 let def = binding.def();
2590 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2591 if let Some(next_module) = binding.module() {
2592 module = Some(next_module);
2593 } else if def == Def::Err {
2594 return PathResult::NonModule(err_path_resolution());
2595 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2596 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2597 def, path.len() - i - 1
2600 return PathResult::Failed(format!("Not a module `{}`", ident), is_last);
2603 Err(Undetermined) => return PathResult::Indeterminate,
2604 Err(Determined) => {
2605 if let Some(module) = module {
2606 if opt_ns.is_some() && !module.is_normal() {
2607 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2608 module.def().unwrap(), path.len() - i
2612 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2613 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2614 let mut candidates =
2615 self.lookup_import_candidates(ident.name, TypeNS, is_mod);
2616 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2617 if let Some(candidate) = candidates.get(0) {
2618 format!("Did you mean `{}`?", candidate.path)
2620 format!("Maybe a missing `extern crate {};`?", ident)
2623 format!("Use of undeclared type or module `{}`", ident)
2625 format!("Could not find `{}` in `{}`", ident, path[i - 1])
2627 return PathResult::Failed(msg, is_last);
2632 PathResult::Module(module.unwrap_or(self.graph_root))
2635 // Resolve a local definition, potentially adjusting for closures.
2636 fn adjust_local_def(&mut self,
2640 record_used: Option<Span>) -> Def {
2641 let ribs = &self.ribs[ns][rib_index + 1..];
2643 // An invalid forward use of a type parameter from a previous default.
2644 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2645 if let Some(span) = record_used {
2646 resolve_error(self, span,
2647 ResolutionError::ForwardDeclaredTyParam);
2649 assert_eq!(def, Def::Err);
2655 span_bug!(record_used.unwrap_or(DUMMY_SP), "unexpected {:?} in bindings", def)
2657 Def::Local(def_id) => {
2660 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2661 ForwardTyParamBanRibKind => {
2662 // Nothing to do. Continue.
2664 ClosureRibKind(function_id) => {
2666 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2668 let seen = self.freevars_seen
2670 .or_insert_with(|| NodeMap());
2671 if let Some(&index) = seen.get(&node_id) {
2672 def = Def::Upvar(def_id, index, function_id);
2675 let vec = self.freevars
2677 .or_insert_with(|| vec![]);
2678 let depth = vec.len();
2679 def = Def::Upvar(def_id, depth, function_id);
2681 if let Some(span) = record_used {
2686 seen.insert(node_id, depth);
2689 ItemRibKind | MethodRibKind(_) => {
2690 // This was an attempt to access an upvar inside a
2691 // named function item. This is not allowed, so we
2693 if let Some(span) = record_used {
2694 resolve_error(self, span,
2695 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2699 ConstantItemRibKind => {
2700 // Still doesn't deal with upvars
2701 if let Some(span) = record_used {
2702 resolve_error(self, span,
2703 ResolutionError::AttemptToUseNonConstantValueInConstant);
2710 Def::TyParam(..) | Def::SelfTy(..) => {
2713 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
2714 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind => {
2715 // Nothing to do. Continue.
2718 // This was an attempt to use a type parameter outside
2720 if let Some(span) = record_used {
2721 resolve_error(self, span,
2722 ResolutionError::TypeParametersFromOuterFunction);
2726 ConstantItemRibKind => {
2728 if let Some(span) = record_used {
2729 resolve_error(self, span,
2730 ResolutionError::OuterTypeParameterContext);
2742 // Calls `f` with a `Resolver` whose current lexical scope is `module`'s lexical scope,
2743 // i.e. the module's items and the prelude (unless the module is `#[no_implicit_prelude]`).
2744 // FIXME #34673: This needs testing.
2745 pub fn with_module_lexical_scope<T, F>(&mut self, module: Module<'a>, f: F) -> T
2746 where F: FnOnce(&mut Resolver<'a>) -> T,
2748 self.with_empty_ribs(|this| {
2749 this.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2750 this.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2755 fn with_empty_ribs<T, F>(&mut self, f: F) -> T
2756 where F: FnOnce(&mut Resolver<'a>) -> T,
2758 let ribs = replace(&mut self.ribs, PerNS::<Vec<Rib>>::default());
2759 let label_ribs = replace(&mut self.label_ribs, Vec::new());
2761 let result = f(self);
2763 self.label_ribs = label_ribs;
2767 fn lookup_assoc_candidate<FilterFn>(&mut self,
2770 filter_fn: FilterFn)
2771 -> Option<AssocSuggestion>
2772 where FilterFn: Fn(Def) -> bool
2774 fn extract_node_id(t: &Ty) -> Option<NodeId> {
2776 TyKind::Path(None, _) => Some(t.id),
2777 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
2778 // This doesn't handle the remaining `Ty` variants as they are not
2779 // that commonly the self_type, it might be interesting to provide
2780 // support for those in future.
2785 // Fields are generally expected in the same contexts as locals.
2786 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
2787 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
2788 // Look for a field with the same name in the current self_type.
2789 if let Some(resolution) = self.def_map.get(&node_id) {
2790 match resolution.base_def() {
2791 Def::Struct(did) | Def::Union(did)
2792 if resolution.unresolved_segments() == 0 => {
2793 if let Some(field_names) = self.field_names.get(&did) {
2794 if field_names.iter().any(|&field_name| name == field_name) {
2795 return Some(AssocSuggestion::Field);
2805 // Look for associated items in the current trait.
2806 if let Some((trait_did, _)) = self.current_trait_ref {
2807 if let Some(&(def, has_self)) = self.trait_item_map.get(&(trait_did, name, ns)) {
2809 return Some(if has_self {
2810 AssocSuggestion::MethodWithSelf
2812 AssocSuggestion::AssocItem
2821 fn lookup_typo_candidate<FilterFn>(&mut self,
2824 filter_fn: FilterFn)
2826 where FilterFn: Fn(Def) -> bool
2828 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
2829 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
2830 if let Some(binding) = resolution.borrow().binding {
2831 if filter_fn(binding.def()) {
2832 names.push(ident.name);
2838 let mut names = Vec::new();
2839 if path.len() == 1 {
2840 // Search in lexical scope.
2841 // Walk backwards up the ribs in scope and collect candidates.
2842 for rib in self.ribs[ns].iter().rev() {
2843 // Locals and type parameters
2844 for (ident, def) in &rib.bindings {
2845 if filter_fn(*def) {
2846 names.push(ident.name);
2850 if let ModuleRibKind(module) = rib.kind {
2851 // Items from this module
2852 add_module_candidates(module, &mut names);
2854 if let ModuleKind::Block(..) = module.kind {
2855 // We can see through blocks
2857 // Items from the prelude
2858 if let Some(prelude) = self.prelude {
2859 if !module.no_implicit_prelude {
2860 add_module_candidates(prelude, &mut names);
2867 // Add primitive types to the mix
2868 if filter_fn(Def::PrimTy(TyBool)) {
2869 for (name, _) in &self.primitive_type_table.primitive_types {
2874 // Search in module.
2875 let mod_path = &path[..path.len() - 1];
2876 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS), None) {
2877 add_module_candidates(module, &mut names);
2881 let name = path[path.len() - 1].name;
2882 // Make sure error reporting is deterministic.
2883 names.sort_by_key(|name| name.as_str());
2884 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
2885 Some(found) if found != name => Some(found),
2890 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
2891 where F: FnOnce(&mut Resolver)
2893 if let Some(label) = label {
2894 let def = Def::Label(id);
2895 self.with_label_rib(|this| {
2896 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
2904 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
2905 self.with_resolved_label(label, id, |this| this.visit_block(block));
2908 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
2909 // First, record candidate traits for this expression if it could
2910 // result in the invocation of a method call.
2912 self.record_candidate_traits_for_expr_if_necessary(expr);
2914 // Next, resolve the node.
2916 ExprKind::Path(ref qself, ref path) => {
2917 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
2918 visit::walk_expr(self, expr);
2921 ExprKind::Struct(ref path, ..) => {
2922 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
2923 visit::walk_expr(self, expr);
2926 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
2927 match self.search_label(label.node) {
2929 self.record_def(expr.id, err_path_resolution());
2932 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
2934 Some(def @ Def::Label(_)) => {
2935 // Since this def is a label, it is never read.
2936 self.record_def(expr.id, PathResolution::new(def));
2939 span_bug!(expr.span, "label wasn't mapped to a label def!");
2943 // visit `break` argument if any
2944 visit::walk_expr(self, expr);
2947 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
2948 self.visit_expr(subexpression);
2950 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2951 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
2952 self.visit_block(if_block);
2953 self.ribs[ValueNS].pop();
2955 optional_else.as_ref().map(|expr| self.visit_expr(expr));
2958 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
2960 ExprKind::While(ref subexpression, ref block, label) => {
2961 self.with_resolved_label(label, expr.id, |this| {
2962 this.visit_expr(subexpression);
2963 this.visit_block(block);
2967 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
2968 self.with_resolved_label(label, expr.id, |this| {
2969 this.visit_expr(subexpression);
2970 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
2971 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
2972 this.visit_block(block);
2973 this.ribs[ValueNS].pop();
2977 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
2978 self.visit_expr(subexpression);
2979 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2980 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
2982 self.resolve_labeled_block(label, expr.id, block);
2984 self.ribs[ValueNS].pop();
2987 // Equivalent to `visit::walk_expr` + passing some context to children.
2988 ExprKind::Field(ref subexpression, _) => {
2989 self.resolve_expr(subexpression, Some(expr));
2991 ExprKind::MethodCall(_, ref types, ref arguments) => {
2992 let mut arguments = arguments.iter();
2993 self.resolve_expr(arguments.next().unwrap(), Some(expr));
2994 for argument in arguments {
2995 self.resolve_expr(argument, None);
2997 for ty in types.iter() {
3002 ExprKind::Repeat(ref element, ref count) => {
3003 self.visit_expr(element);
3004 self.with_constant_rib(|this| {
3005 this.visit_expr(count);
3008 ExprKind::Call(ref callee, ref arguments) => {
3009 self.resolve_expr(callee, Some(expr));
3010 for argument in arguments {
3011 self.resolve_expr(argument, None);
3016 visit::walk_expr(self, expr);
3021 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3023 ExprKind::Field(_, name) => {
3024 // FIXME(#6890): Even though you can't treat a method like a
3025 // field, we need to add any trait methods we find that match
3026 // the field name so that we can do some nice error reporting
3027 // later on in typeck.
3028 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3029 self.trait_map.insert(expr.id, traits);
3031 ExprKind::MethodCall(name, ..) => {
3032 debug!("(recording candidate traits for expr) recording traits for {}",
3034 let traits = self.get_traits_containing_item(name.node.name, ValueNS);
3035 self.trait_map.insert(expr.id, traits);
3043 fn get_traits_containing_item(&mut self, name: Name, ns: Namespace) -> Vec<TraitCandidate> {
3044 debug!("(getting traits containing item) looking for '{}'", name);
3046 let mut found_traits = Vec::new();
3047 // Look for the current trait.
3048 if let Some((trait_def_id, _)) = self.current_trait_ref {
3049 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3050 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: None });
3054 let mut search_module = self.current_module;
3056 self.get_traits_in_module_containing_item(name, ns, search_module, &mut found_traits);
3057 match search_module.kind {
3058 ModuleKind::Block(..) => search_module = search_module.parent.unwrap(),
3063 if let Some(prelude) = self.prelude {
3064 if !search_module.no_implicit_prelude {
3065 self.get_traits_in_module_containing_item(name, ns, prelude, &mut found_traits);
3072 fn get_traits_in_module_containing_item(&mut self,
3076 found_traits: &mut Vec<TraitCandidate>) {
3077 let mut traits = module.traits.borrow_mut();
3078 if traits.is_none() {
3079 let mut collected_traits = Vec::new();
3080 module.for_each_child(|name, ns, binding| {
3081 if ns != TypeNS { return }
3082 if let Def::Trait(_) = binding.def() {
3083 collected_traits.push((name, binding));
3086 *traits = Some(collected_traits.into_boxed_slice());
3089 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3090 let trait_def_id = binding.def().def_id();
3091 if self.trait_item_map.contains_key(&(trait_def_id, name, ns)) {
3092 let import_id = match binding.kind {
3093 NameBindingKind::Import { directive, .. } => {
3094 self.maybe_unused_trait_imports.insert(directive.id);
3095 self.add_to_glob_map(directive.id, trait_name);
3100 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3105 /// When name resolution fails, this method can be used to look up candidate
3106 /// entities with the expected name. It allows filtering them using the
3107 /// supplied predicate (which should be used to only accept the types of
3108 /// definitions expected e.g. traits). The lookup spans across all crates.
3110 /// NOTE: The method does not look into imports, but this is not a problem,
3111 /// since we report the definitions (thus, the de-aliased imports).
3112 fn lookup_import_candidates<FilterFn>(&mut self,
3114 namespace: Namespace,
3115 filter_fn: FilterFn)
3116 -> Vec<ImportSuggestion>
3117 where FilterFn: Fn(Def) -> bool
3119 let mut candidates = Vec::new();
3120 let mut worklist = Vec::new();
3121 let mut seen_modules = FxHashSet();
3122 worklist.push((self.graph_root, Vec::new(), false));
3124 while let Some((in_module,
3126 in_module_is_extern)) = worklist.pop() {
3127 self.populate_module_if_necessary(in_module);
3129 in_module.for_each_child(|ident, ns, name_binding| {
3131 // avoid imports entirely
3132 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3133 // avoid non-importable candidates as well
3134 if !name_binding.is_importable() { return; }
3136 // collect results based on the filter function
3137 if ident.name == lookup_name && ns == namespace {
3138 if filter_fn(name_binding.def()) {
3140 let mut segms = path_segments.clone();
3141 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3143 span: name_binding.span,
3146 // the entity is accessible in the following cases:
3147 // 1. if it's defined in the same crate, it's always
3148 // accessible (since private entities can be made public)
3149 // 2. if it's defined in another crate, it's accessible
3150 // only if both the module is public and the entity is
3151 // declared as public (due to pruning, we don't explore
3152 // outside crate private modules => no need to check this)
3153 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3154 candidates.push(ImportSuggestion { path: path });
3159 // collect submodules to explore
3160 if let Some(module) = name_binding.module() {
3162 let mut path_segments = path_segments.clone();
3163 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3165 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3166 // add the module to the lookup
3167 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3168 if seen_modules.insert(module.def_id().unwrap()) {
3169 worklist.push((module, path_segments, is_extern));
3179 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3180 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3181 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3182 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3186 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3188 ast::Visibility::Public => ty::Visibility::Public,
3189 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3190 ast::Visibility::Inherited => {
3191 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3193 ast::Visibility::Restricted { ref path, id } => {
3194 let def = self.smart_resolve_path(id, None, path,
3195 PathSource::Visibility).base_def();
3196 if def == Def::Err {
3197 ty::Visibility::Public
3199 let vis = ty::Visibility::Restricted(def.def_id());
3200 if self.is_accessible(vis) {
3203 self.session.span_err(path.span, "visibilities can only be restricted \
3204 to ancestor modules");
3205 ty::Visibility::Public
3212 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3213 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3216 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3217 vis.is_accessible_from(module.normal_ancestor_id, self)
3220 fn report_errors(&mut self) {
3221 self.report_shadowing_errors();
3222 let mut reported_spans = FxHashSet();
3224 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3225 if !reported_spans.insert(span) { continue }
3226 let participle = |binding: &NameBinding| {
3227 if binding.is_import() { "imported" } else { "defined" }
3229 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3230 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3231 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3232 format!("consider adding an explicit import of `{}` to disambiguate", name)
3233 } else if let Def::Macro(..) = b1.def() {
3234 format!("macro-expanded {} do not shadow",
3235 if b1.is_import() { "macro imports" } else { "macros" })
3237 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3238 if b1.is_import() { "imports" } else { "items" })
3241 let id = match b2.kind {
3242 NameBindingKind::Import { directive, .. } => directive.id,
3243 _ => unreachable!(),
3245 let mut span = MultiSpan::from_span(span);
3246 span.push_span_label(b1.span, msg1);
3247 span.push_span_label(b2.span, msg2);
3248 let msg = format!("`{}` is ambiguous", name);
3249 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3252 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3253 err.span_note(b1.span, &msg1);
3255 Def::Macro(..) if b2.span == DUMMY_SP =>
3256 err.note(&format!("`{}` is also a builtin macro", name)),
3257 _ => err.span_note(b2.span, &msg2),
3259 err.note(¬e).emit();
3263 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3264 if !reported_spans.insert(span) { continue }
3265 if binding.is_extern_crate() {
3266 // Warn when using an inaccessible extern crate.
3267 let node_id = match binding.kind {
3268 NameBindingKind::Import { directive, .. } => directive.id,
3269 _ => unreachable!(),
3271 let msg = format!("extern crate `{}` is private", name);
3272 self.session.add_lint(lint::builtin::INACCESSIBLE_EXTERN_CRATE, node_id, span, msg);
3274 let def = binding.def();
3275 self.session.span_err(span, &format!("{} `{}` is private", def.kind_name(), name));
3280 fn report_shadowing_errors(&mut self) {
3281 for (name, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3282 self.resolve_legacy_scope(scope, name, true);
3285 let mut reported_errors = FxHashSet();
3286 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3287 if self.resolve_legacy_scope(&binding.parent, binding.name, false).is_some() &&
3288 reported_errors.insert((binding.name, binding.span)) {
3289 let msg = format!("`{}` is already in scope", binding.name);
3290 self.session.struct_span_err(binding.span, &msg)
3291 .note("macro-expanded `macro_rules!`s may not shadow \
3292 existing macros (see RFC 1560)")
3298 fn report_conflict(&mut self,
3302 binding: &NameBinding,
3303 old_binding: &NameBinding) {
3304 // Error on the second of two conflicting names
3305 if old_binding.span.lo > binding.span.lo {
3306 return self.report_conflict(parent, ident, ns, old_binding, binding);
3309 let container = match parent.kind {
3310 ModuleKind::Def(Def::Mod(_), _) => "module",
3311 ModuleKind::Def(Def::Trait(_), _) => "trait",
3312 ModuleKind::Block(..) => "block",
3316 let (participle, noun) = match old_binding.is_import() {
3317 true => ("imported", "import"),
3318 false => ("defined", "definition"),
3321 let (name, span) = (ident.name, binding.span);
3323 if let Some(s) = self.name_already_seen.get(&name) {
3330 let kind = match (ns, old_binding.module()) {
3331 (ValueNS, _) => "a value",
3332 (MacroNS, _) => "a macro",
3333 (TypeNS, _) if old_binding.is_extern_crate() => "an extern crate",
3334 (TypeNS, Some(module)) if module.is_normal() => "a module",
3335 (TypeNS, Some(module)) if module.is_trait() => "a trait",
3336 (TypeNS, _) => "a type",
3338 format!("{} named `{}` has already been {} in this {}",
3339 kind, name, participle, container)
3342 let mut err = match (old_binding.is_extern_crate(), binding.is_extern_crate()) {
3343 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3344 (true, _) | (_, true) => match binding.is_import() && old_binding.is_import() {
3345 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3346 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3348 _ => match (old_binding.is_import(), binding.is_import()) {
3349 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3350 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3351 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3355 err.span_label(span, &format!("`{}` already {}", name, participle));
3356 if old_binding.span != syntax_pos::DUMMY_SP {
3357 err.span_label(old_binding.span, &format!("previous {} of `{}` here", noun, name));
3360 self.name_already_seen.insert(name, span);
3363 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3364 let (id, span) = (directive.id, directive.span);
3365 let msg = "`self` no longer imports values".to_string();
3366 self.session.add_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3369 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3370 if self.proc_macro_enabled { return; }
3373 if attr.path.segments.len() > 1 {
3376 let ident = attr.path.segments[0].identifier;
3377 let result = self.resolve_lexical_macro_path_segment(ident, MacroNS, None);
3378 if let Ok(binding) = result {
3379 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3380 attr::mark_known(attr);
3382 let msg = "attribute procedural macros are experimental";
3383 let feature = "proc_macro";
3385 feature_err(&self.session.parse_sess, feature,
3386 attr.span, GateIssue::Language, msg)
3387 .span_note(binding.span(), "procedural macro imported here")
3395 fn is_struct_like(def: Def) -> bool {
3397 Def::VariantCtor(_, CtorKind::Fictive) => true,
3398 _ => PathSource::Struct.is_expected(def),
3402 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
3403 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
3406 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
3407 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
3410 fn names_to_string(idents: &[Ident]) -> String {
3411 let mut result = String::new();
3412 for (i, ident) in idents.iter().filter(|i| i.name != keywords::CrateRoot.name()).enumerate() {
3414 result.push_str("::");
3416 result.push_str(&ident.name.as_str());
3421 fn path_names_to_string(path: &Path) -> String {
3422 names_to_string(&path.segments.iter().map(|seg| seg.identifier).collect::<Vec<_>>())
3425 /// When an entity with a given name is not available in scope, we search for
3426 /// entities with that name in all crates. This method allows outputting the
3427 /// results of this search in a programmer-friendly way
3428 fn show_candidates(session: &mut DiagnosticBuilder,
3429 candidates: &[ImportSuggestion],
3431 // don't show more than MAX_CANDIDATES results, so
3432 // we're consistent with the trait suggestions
3433 const MAX_CANDIDATES: usize = 4;
3435 // we want consistent results across executions, but candidates are produced
3436 // by iterating through a hash map, so make sure they are ordered:
3437 let mut path_strings: Vec<_> =
3438 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3439 path_strings.sort();
3441 let better = if better { "better " } else { "" };
3442 let msg_diff = match path_strings.len() {
3443 1 => " is found in another module, you can import it",
3444 _ => "s are found in other modules, you can import them",
3447 let end = cmp::min(MAX_CANDIDATES, path_strings.len());
3448 session.help(&format!("possible {}candidate{} into scope:{}{}",
3451 &path_strings[0..end].iter().map(|candidate| {
3452 format!("\n `use {};`", candidate)
3453 }).collect::<String>(),
3454 if path_strings.len() > MAX_CANDIDATES {
3455 format!("\nand {} other candidates",
3456 path_strings.len() - MAX_CANDIDATES)
3463 /// A somewhat inefficient routine to obtain the name of a module.
3464 fn module_to_string(module: Module) -> String {
3465 let mut names = Vec::new();
3467 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3468 if let ModuleKind::Def(_, name) = module.kind {
3469 if let Some(parent) = module.parent {
3470 names.push(Ident::with_empty_ctxt(name));
3471 collect_mod(names, parent);
3474 // danger, shouldn't be ident?
3475 names.push(Ident::from_str("<opaque>"));
3476 collect_mod(names, module.parent.unwrap());
3479 collect_mod(&mut names, module);
3481 if names.is_empty() {
3482 return "???".to_string();
3484 names_to_string(&names.into_iter().rev().collect::<Vec<_>>())
3487 fn err_path_resolution() -> PathResolution {
3488 PathResolution::new(Def::Err)
3491 #[derive(PartialEq,Copy, Clone)]
3492 pub enum MakeGlobMap {
3497 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }