1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
16 #![feature(rustc_diagnostic_macros)]
22 extern crate syntax_pos;
23 extern crate rustc_errors as errors;
28 use self::Namespace::*;
29 use self::TypeParameters::*;
32 use rustc::hir::map::{Definitions, DefCollector};
33 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
34 use rustc::middle::cstore::CrateLoader;
35 use rustc::session::Session;
37 use rustc::hir::def::*;
38 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
40 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
41 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
43 use syntax::codemap::{dummy_spanned, respan};
44 use syntax::ext::hygiene::{Mark, SyntaxContext};
45 use syntax::ast::{self, Name, NodeId, Ident, SpannedIdent, FloatTy, IntTy, UintTy};
46 use syntax::ext::base::SyntaxExtension;
47 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
48 use syntax::ext::base::MacroKind;
49 use syntax::symbol::{Symbol, keywords};
50 use syntax::util::lev_distance::find_best_match_for_name;
52 use syntax::visit::{self, FnKind, Visitor};
54 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
55 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, Generics};
56 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
57 use syntax::ast::{Local, Mutability, Pat, PatKind, Path};
58 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
59 use syntax::feature_gate::{feature_err, emit_feature_err, GateIssue};
61 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
62 use errors::DiagnosticBuilder;
64 use std::cell::{Cell, RefCell};
66 use std::collections::BTreeSet;
68 use std::mem::replace;
71 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
72 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
74 // NB: This module needs to be declared first so diagnostics are
75 // registered before they are used.
80 mod build_reduced_graph;
83 /// A free importable items suggested in case of resolution failure.
84 struct ImportSuggestion {
88 /// A field or associated item from self type suggested in case of resolution failure.
89 enum AssocSuggestion {
98 origin: BTreeSet<Span>,
99 target: BTreeSet<Span>,
102 impl PartialOrd for BindingError {
103 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
104 Some(self.cmp(other))
108 impl PartialEq for BindingError {
109 fn eq(&self, other: &BindingError) -> bool {
110 self.name == other.name
114 impl Ord for BindingError {
115 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
116 self.name.cmp(&other.name)
120 enum ResolutionError<'a> {
121 /// error E0401: can't use type parameters from outer function
122 TypeParametersFromOuterFunction,
123 /// error E0403: the name is already used for a type parameter in this type parameter list
124 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
125 /// error E0407: method is not a member of trait
126 MethodNotMemberOfTrait(Name, &'a str),
127 /// error E0437: type is not a member of trait
128 TypeNotMemberOfTrait(Name, &'a str),
129 /// error E0438: const is not a member of trait
130 ConstNotMemberOfTrait(Name, &'a str),
131 /// error E0408: variable `{}` is not bound in all patterns
132 VariableNotBoundInPattern(&'a BindingError),
133 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
134 VariableBoundWithDifferentMode(Name, Span),
135 /// error E0415: identifier is bound more than once in this parameter list
136 IdentifierBoundMoreThanOnceInParameterList(&'a str),
137 /// error E0416: identifier is bound more than once in the same pattern
138 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
139 /// error E0426: use of undeclared label
140 UndeclaredLabel(&'a str),
141 /// error E0429: `self` imports are only allowed within a { } list
142 SelfImportsOnlyAllowedWithin,
143 /// error E0430: `self` import can only appear once in the list
144 SelfImportCanOnlyAppearOnceInTheList,
145 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
146 SelfImportOnlyInImportListWithNonEmptyPrefix,
147 /// error E0432: unresolved import
148 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
149 /// error E0433: failed to resolve
150 FailedToResolve(&'a str),
151 /// error E0434: can't capture dynamic environment in a fn item
152 CannotCaptureDynamicEnvironmentInFnItem,
153 /// error E0435: attempt to use a non-constant value in a constant
154 AttemptToUseNonConstantValueInConstant,
155 /// error E0530: X bindings cannot shadow Ys
156 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
157 /// error E0128: type parameters with a default cannot use forward declared identifiers
158 ForwardDeclaredTyParam,
161 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
163 resolution_error: ResolutionError<'a>) {
164 resolve_struct_error(resolver, span, resolution_error).emit();
167 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
169 resolution_error: ResolutionError<'a>)
170 -> DiagnosticBuilder<'sess> {
171 match resolution_error {
172 ResolutionError::TypeParametersFromOuterFunction => {
173 let mut err = struct_span_err!(resolver.session,
176 "can't use type parameters from outer function; \
177 try using a local type parameter instead");
178 err.span_label(span, "use of type variable from outer function");
181 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
182 let mut err = struct_span_err!(resolver.session,
185 "the name `{}` is already used for a type parameter \
186 in this type parameter list",
188 err.span_label(span, "already used");
189 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
192 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
193 let mut err = struct_span_err!(resolver.session,
196 "method `{}` is not a member of trait `{}`",
199 err.span_label(span, format!("not a member of trait `{}`", trait_));
202 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
203 let mut err = struct_span_err!(resolver.session,
206 "type `{}` is not a member of trait `{}`",
209 err.span_label(span, format!("not a member of trait `{}`", trait_));
212 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
213 let mut err = struct_span_err!(resolver.session,
216 "const `{}` is not a member of trait `{}`",
219 err.span_label(span, format!("not a member of trait `{}`", trait_));
222 ResolutionError::VariableNotBoundInPattern(binding_error) => {
223 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
224 let msp = MultiSpan::from_spans(target_sp.clone());
225 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
226 let mut err = resolver.session.struct_span_err_with_code(msp, &msg, "E0408");
227 for sp in target_sp {
228 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
230 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
231 for sp in origin_sp {
232 err.span_label(sp, "variable not in all patterns");
236 ResolutionError::VariableBoundWithDifferentMode(variable_name,
237 first_binding_span) => {
238 let mut err = struct_span_err!(resolver.session,
241 "variable `{}` is bound in inconsistent \
242 ways within the same match arm",
244 err.span_label(span, "bound in different ways");
245 err.span_label(first_binding_span, "first binding");
248 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
249 let mut err = struct_span_err!(resolver.session,
252 "identifier `{}` is bound more than once in this parameter list",
254 err.span_label(span, "used as parameter more than once");
257 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
258 let mut err = struct_span_err!(resolver.session,
261 "identifier `{}` is bound more than once in the same pattern",
263 err.span_label(span, "used in a pattern more than once");
266 ResolutionError::UndeclaredLabel(name) => {
267 let mut err = struct_span_err!(resolver.session,
270 "use of undeclared label `{}`",
272 err.span_label(span, format!("undeclared label `{}`", name));
275 ResolutionError::SelfImportsOnlyAllowedWithin => {
276 struct_span_err!(resolver.session,
280 "`self` imports are only allowed within a { } list")
282 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
283 struct_span_err!(resolver.session,
286 "`self` import can only appear once in the list")
288 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
289 struct_span_err!(resolver.session,
292 "`self` import can only appear in an import list with a \
295 ResolutionError::UnresolvedImport(name) => {
296 let (span, msg) = match name {
297 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
298 None => (span, "unresolved import".to_owned()),
300 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
301 if let Some((_, _, p)) = name {
302 err.span_label(span, p);
306 ResolutionError::FailedToResolve(msg) => {
307 let mut err = struct_span_err!(resolver.session, span, E0433,
308 "failed to resolve. {}", msg);
309 err.span_label(span, msg);
312 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
313 struct_span_err!(resolver.session,
317 "can't capture dynamic environment in a fn item; use the || { ... } \
318 closure form instead")
320 ResolutionError::AttemptToUseNonConstantValueInConstant => {
321 let mut err = struct_span_err!(resolver.session,
324 "attempt to use a non-constant value in a constant");
325 err.span_label(span, "non-constant value");
328 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
329 let shadows_what = PathResolution::new(binding.def()).kind_name();
330 let mut err = struct_span_err!(resolver.session,
333 "{}s cannot shadow {}s", what_binding, shadows_what);
334 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
335 let participle = if binding.is_import() { "imported" } else { "defined" };
336 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
337 err.span_label(binding.span, msg);
340 ResolutionError::ForwardDeclaredTyParam => {
341 let mut err = struct_span_err!(resolver.session, span, E0128,
342 "type parameters with a default cannot use \
343 forward declared identifiers");
344 err.span_label(span, format!("defaulted type parameters \
345 cannot be forward declared"));
351 #[derive(Copy, Clone, Debug)]
354 binding_mode: BindingMode,
357 // Map from the name in a pattern to its binding mode.
358 type BindingMap = FxHashMap<Ident, BindingInfo>;
360 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
371 fn is_refutable(self) -> bool {
373 PatternSource::Match | PatternSource::IfLet | PatternSource::WhileLet => true,
374 PatternSource::Let | PatternSource::For | PatternSource::FnParam => false,
377 fn descr(self) -> &'static str {
379 PatternSource::Match => "match binding",
380 PatternSource::IfLet => "if let binding",
381 PatternSource::WhileLet => "while let binding",
382 PatternSource::Let => "let binding",
383 PatternSource::For => "for binding",
384 PatternSource::FnParam => "function parameter",
389 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
390 enum PathSource<'a> {
391 // Type paths `Path`.
393 // Trait paths in bounds or impls.
395 // Expression paths `path`, with optional parent context.
396 Expr(Option<&'a Expr>),
397 // Paths in path patterns `Path`.
399 // Paths in struct expressions and patterns `Path { .. }`.
401 // Paths in tuple struct patterns `Path(..)`.
403 // `m::A::B` in `<T as m::A>::B::C`.
404 TraitItem(Namespace),
405 // Path in `pub(path)`
407 // Path in `use a::b::{...};`
411 impl<'a> PathSource<'a> {
412 fn namespace(self) -> Namespace {
414 PathSource::Type | PathSource::Trait | PathSource::Struct |
415 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
416 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
417 PathSource::TraitItem(ns) => ns,
421 fn global_by_default(self) -> bool {
423 PathSource::Visibility | PathSource::ImportPrefix => true,
424 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
425 PathSource::Struct | PathSource::TupleStruct |
426 PathSource::Trait | PathSource::TraitItem(..) => false,
430 fn defer_to_typeck(self) -> bool {
432 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
433 PathSource::Struct | PathSource::TupleStruct => true,
434 PathSource::Trait | PathSource::TraitItem(..) |
435 PathSource::Visibility | PathSource::ImportPrefix => false,
439 fn descr_expected(self) -> &'static str {
441 PathSource::Type => "type",
442 PathSource::Trait => "trait",
443 PathSource::Pat => "unit struct/variant or constant",
444 PathSource::Struct => "struct, variant or union type",
445 PathSource::TupleStruct => "tuple struct/variant",
446 PathSource::Visibility => "module",
447 PathSource::ImportPrefix => "module or enum",
448 PathSource::TraitItem(ns) => match ns {
449 TypeNS => "associated type",
450 ValueNS => "method or associated constant",
451 MacroNS => bug!("associated macro"),
453 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
454 // "function" here means "anything callable" rather than `Def::Fn`,
455 // this is not precise but usually more helpful than just "value".
456 Some(&ExprKind::Call(..)) => "function",
462 fn is_expected(self, def: Def) -> bool {
464 PathSource::Type => match def {
465 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
466 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
467 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) => true,
470 PathSource::Trait => match def {
471 Def::Trait(..) => true,
474 PathSource::Expr(..) => match def {
475 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
476 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
477 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
478 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
481 PathSource::Pat => match def {
482 Def::StructCtor(_, CtorKind::Const) |
483 Def::VariantCtor(_, CtorKind::Const) |
484 Def::Const(..) | Def::AssociatedConst(..) => true,
487 PathSource::TupleStruct => match def {
488 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
491 PathSource::Struct => match def {
492 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
493 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
496 PathSource::TraitItem(ns) => match def {
497 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
498 Def::AssociatedTy(..) if ns == TypeNS => true,
501 PathSource::ImportPrefix => match def {
502 Def::Mod(..) | Def::Enum(..) => true,
505 PathSource::Visibility => match def {
506 Def::Mod(..) => true,
512 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
513 __diagnostic_used!(E0404);
514 __diagnostic_used!(E0405);
515 __diagnostic_used!(E0412);
516 __diagnostic_used!(E0422);
517 __diagnostic_used!(E0423);
518 __diagnostic_used!(E0425);
519 __diagnostic_used!(E0531);
520 __diagnostic_used!(E0532);
521 __diagnostic_used!(E0573);
522 __diagnostic_used!(E0574);
523 __diagnostic_used!(E0575);
524 __diagnostic_used!(E0576);
525 __diagnostic_used!(E0577);
526 __diagnostic_used!(E0578);
527 match (self, has_unexpected_resolution) {
528 (PathSource::Trait, true) => "E0404",
529 (PathSource::Trait, false) => "E0405",
530 (PathSource::Type, true) => "E0573",
531 (PathSource::Type, false) => "E0412",
532 (PathSource::Struct, true) => "E0574",
533 (PathSource::Struct, false) => "E0422",
534 (PathSource::Expr(..), true) => "E0423",
535 (PathSource::Expr(..), false) => "E0425",
536 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
537 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
538 (PathSource::TraitItem(..), true) => "E0575",
539 (PathSource::TraitItem(..), false) => "E0576",
540 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
541 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
546 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
553 #[derive(Clone, Default, Debug)]
554 pub struct PerNS<T> {
560 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
562 fn index(&self, ns: Namespace) -> &T {
564 ValueNS => &self.value_ns,
565 TypeNS => &self.type_ns,
566 MacroNS => self.macro_ns.as_ref().unwrap(),
571 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
572 fn index_mut(&mut self, ns: Namespace) -> &mut T {
574 ValueNS => &mut self.value_ns,
575 TypeNS => &mut self.type_ns,
576 MacroNS => self.macro_ns.as_mut().unwrap(),
581 struct UsePlacementFinder {
582 target_module: NodeId,
587 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
590 module: &'tcx ast::Mod,
592 _: &[ast::Attribute],
595 if self.span.is_some() {
598 if node_id != self.target_module {
599 visit::walk_mod(self, module);
602 // find a use statement
603 for item in &module.items {
605 ItemKind::Use(..) => {
606 // don't suggest placing a use before the prelude
607 // import or other generated ones
608 if item.span == DUMMY_SP {
609 let mut span = item.span;
611 self.span = Some(span);
612 self.found_use = true;
616 // don't place use before extern crate
617 ItemKind::ExternCrate(_) => {}
618 // but place them before the first other item
619 _ => if self.span.map_or(true, |span| item.span < span ) {
620 let mut span = item.span;
622 self.span = Some(span);
626 assert!(self.span.is_some(), "a file can't have no items and emit suggestions");
630 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
631 fn visit_item(&mut self, item: &'tcx Item) {
632 self.resolve_item(item);
634 fn visit_arm(&mut self, arm: &'tcx Arm) {
635 self.resolve_arm(arm);
637 fn visit_block(&mut self, block: &'tcx Block) {
638 self.resolve_block(block);
640 fn visit_expr(&mut self, expr: &'tcx Expr) {
641 self.resolve_expr(expr, None);
643 fn visit_local(&mut self, local: &'tcx Local) {
644 self.resolve_local(local);
646 fn visit_ty(&mut self, ty: &'tcx Ty) {
648 TyKind::Path(ref qself, ref path) => {
649 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
651 TyKind::ImplicitSelf => {
652 let self_ty = keywords::SelfType.ident();
653 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
654 .map_or(Def::Err, |d| d.def());
655 self.record_def(ty.id, PathResolution::new(def));
657 TyKind::Array(ref element, ref length) => {
658 self.visit_ty(element);
659 self.with_constant_rib(|this| {
660 this.visit_expr(length);
666 visit::walk_ty(self, ty);
668 fn visit_poly_trait_ref(&mut self,
669 tref: &'tcx ast::PolyTraitRef,
670 m: &'tcx ast::TraitBoundModifier) {
671 self.smart_resolve_path(tref.trait_ref.ref_id, None,
672 &tref.trait_ref.path, PathSource::Trait);
673 visit::walk_poly_trait_ref(self, tref, m);
675 fn visit_variant(&mut self,
676 variant: &'tcx ast::Variant,
677 generics: &'tcx Generics,
678 item_id: ast::NodeId) {
679 if let Some(ref dis_expr) = variant.node.disr_expr {
680 // resolve the discriminator expr as a constant
681 self.with_constant_rib(|this| {
682 this.visit_expr(dis_expr);
686 // `visit::walk_variant` without the discriminant expression.
687 self.visit_variant_data(&variant.node.data,
693 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
694 let type_parameters = match foreign_item.node {
695 ForeignItemKind::Fn(_, ref generics) => {
696 HasTypeParameters(generics, ItemRibKind)
698 ForeignItemKind::Static(..) => NoTypeParameters,
700 self.with_type_parameter_rib(type_parameters, |this| {
701 visit::walk_foreign_item(this, foreign_item);
704 fn visit_fn(&mut self,
705 function_kind: FnKind<'tcx>,
706 declaration: &'tcx FnDecl,
709 let rib_kind = match function_kind {
710 FnKind::ItemFn(_, generics, ..) => {
711 self.visit_generics(generics);
714 FnKind::Method(_, sig, _, _) => {
715 self.visit_generics(&sig.generics);
716 MethodRibKind(!sig.decl.has_self())
718 FnKind::Closure(_) => ClosureRibKind(node_id),
721 // Create a value rib for the function.
722 self.ribs[ValueNS].push(Rib::new(rib_kind));
724 // Create a label rib for the function.
725 self.label_ribs.push(Rib::new(rib_kind));
727 // Add each argument to the rib.
728 let mut bindings_list = FxHashMap();
729 for argument in &declaration.inputs {
730 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
732 self.visit_ty(&argument.ty);
734 debug!("(resolving function) recorded argument");
736 visit::walk_fn_ret_ty(self, &declaration.output);
738 // Resolve the function body.
739 match function_kind {
740 FnKind::ItemFn(.., body) |
741 FnKind::Method(.., body) => {
742 self.visit_block(body);
744 FnKind::Closure(body) => {
745 self.visit_expr(body);
749 debug!("(resolving function) leaving function");
751 self.label_ribs.pop();
752 self.ribs[ValueNS].pop();
754 fn visit_generics(&mut self, generics: &'tcx Generics) {
755 // For type parameter defaults, we have to ban access
756 // to following type parameters, as the Substs can only
757 // provide previous type parameters as they're built.
758 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
759 default_ban_rib.bindings.extend(generics.ty_params.iter()
760 .skip_while(|p| p.default.is_none())
761 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
763 for param in &generics.ty_params {
764 for bound in ¶m.bounds {
765 self.visit_ty_param_bound(bound);
768 if let Some(ref ty) = param.default {
769 self.ribs[TypeNS].push(default_ban_rib);
771 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
774 // Allow all following defaults to refer to this type parameter.
775 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
777 for lt in &generics.lifetimes { self.visit_lifetime_def(lt); }
778 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
782 #[derive(Copy, Clone)]
783 enum TypeParameters<'a, 'b> {
785 HasTypeParameters(// Type parameters.
788 // The kind of the rib used for type parameters.
792 // The rib kind controls the translation of local
793 // definitions (`Def::Local`) to upvars (`Def::Upvar`).
794 #[derive(Copy, Clone, Debug)]
796 // No translation needs to be applied.
799 // We passed through a closure scope at the given node ID.
800 // Translate upvars as appropriate.
801 ClosureRibKind(NodeId /* func id */),
803 // We passed through an impl or trait and are now in one of its
804 // methods. Allow references to ty params that impl or trait
805 // binds. Disallow any other upvars (including other ty params that are
808 // The boolean value represents the fact that this method is static or not.
811 // We passed through an item scope. Disallow upvars.
814 // We're in a constant item. Can't refer to dynamic stuff.
817 // We passed through a module.
818 ModuleRibKind(Module<'a>),
820 // We passed through a `macro_rules!` statement
821 MacroDefinition(DefId),
823 // All bindings in this rib are type parameters that can't be used
824 // from the default of a type parameter because they're not declared
825 // before said type parameter. Also see the `visit_generics` override.
826 ForwardTyParamBanRibKind,
832 bindings: FxHashMap<Ident, Def>,
837 fn new(kind: RibKind<'a>) -> Rib<'a> {
839 bindings: FxHashMap(),
845 enum LexicalScopeBinding<'a> {
846 Item(&'a NameBinding<'a>),
850 impl<'a> LexicalScopeBinding<'a> {
851 fn item(self) -> Option<&'a NameBinding<'a>> {
853 LexicalScopeBinding::Item(binding) => Some(binding),
858 fn def(self) -> Def {
860 LexicalScopeBinding::Item(binding) => binding.def(),
861 LexicalScopeBinding::Def(def) => def,
867 enum PathResult<'a> {
869 NonModule(PathResolution),
871 Failed(Span, String, bool /* is the error from the last segment? */),
879 /// One node in the tree of modules.
880 pub struct ModuleData<'a> {
881 parent: Option<Module<'a>>,
884 // The def id of the closest normal module (`mod`) ancestor (including this module).
885 normal_ancestor_id: DefId,
887 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
888 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
889 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
891 // Macro invocations that can expand into items in this module.
892 unresolved_invocations: RefCell<FxHashSet<Mark>>,
894 no_implicit_prelude: bool,
896 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
897 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
899 // Used to memoize the traits in this module for faster searches through all traits in scope.
900 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
902 // Whether this module is populated. If not populated, any attempt to
903 // access the children must be preceded with a
904 // `populate_module_if_necessary` call.
905 populated: Cell<bool>,
907 /// Span of the module itself. Used for error reporting.
913 type Module<'a> = &'a ModuleData<'a>;
915 impl<'a> ModuleData<'a> {
916 fn new(parent: Option<Module<'a>>,
918 normal_ancestor_id: DefId,
920 span: Span) -> Self {
925 resolutions: RefCell::new(FxHashMap()),
926 legacy_macro_resolutions: RefCell::new(Vec::new()),
927 macro_resolutions: RefCell::new(Vec::new()),
928 unresolved_invocations: RefCell::new(FxHashSet()),
929 no_implicit_prelude: false,
930 glob_importers: RefCell::new(Vec::new()),
931 globs: RefCell::new((Vec::new())),
932 traits: RefCell::new(None),
933 populated: Cell::new(normal_ancestor_id.is_local()),
939 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
940 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
941 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
945 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
946 let resolutions = self.resolutions.borrow();
947 let mut resolutions = resolutions.iter().map(|(&(ident, ns), &resolution)| {
948 // Pre-compute keys for sorting
949 (ident.name.as_str(), ns, ident, resolution)
951 .collect::<Vec<_>>();
952 resolutions.sort_unstable_by_key(|&(str, ns, ..)| (str, ns));
953 for &(_, ns, ident, resolution) in resolutions.iter() {
954 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
958 fn def(&self) -> Option<Def> {
960 ModuleKind::Def(def, _) => Some(def),
965 fn def_id(&self) -> Option<DefId> {
966 self.def().as_ref().map(Def::def_id)
969 // `self` resolves to the first module ancestor that `is_normal`.
970 fn is_normal(&self) -> bool {
972 ModuleKind::Def(Def::Mod(_), _) => true,
977 fn is_trait(&self) -> bool {
979 ModuleKind::Def(Def::Trait(_), _) => true,
984 fn is_local(&self) -> bool {
985 self.normal_ancestor_id.is_local()
988 fn nearest_item_scope(&'a self) -> Module<'a> {
989 if self.is_trait() { self.parent.unwrap() } else { self }
993 impl<'a> fmt::Debug for ModuleData<'a> {
994 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
995 write!(f, "{:?}", self.def())
999 // Records a possibly-private value, type, or module definition.
1000 #[derive(Clone, Debug)]
1001 pub struct NameBinding<'a> {
1002 kind: NameBindingKind<'a>,
1005 vis: ty::Visibility,
1008 pub trait ToNameBinding<'a> {
1009 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1012 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1013 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1018 #[derive(Clone, Debug)]
1019 enum NameBindingKind<'a> {
1023 binding: &'a NameBinding<'a>,
1024 directive: &'a ImportDirective<'a>,
1026 legacy_self_import: bool,
1029 b1: &'a NameBinding<'a>,
1030 b2: &'a NameBinding<'a>,
1035 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1037 struct UseError<'a> {
1038 err: DiagnosticBuilder<'a>,
1039 /// Attach `use` statements for these candidates
1040 candidates: Vec<ImportSuggestion>,
1041 /// The node id of the module to place the use statements in
1043 /// Whether the diagnostic should state that it's "better"
1047 struct AmbiguityError<'a> {
1051 b1: &'a NameBinding<'a>,
1052 b2: &'a NameBinding<'a>,
1056 impl<'a> NameBinding<'a> {
1057 fn module(&self) -> Option<Module<'a>> {
1059 NameBindingKind::Module(module) => Some(module),
1060 NameBindingKind::Import { binding, .. } => binding.module(),
1061 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1066 fn def(&self) -> Def {
1068 NameBindingKind::Def(def) => def,
1069 NameBindingKind::Module(module) => module.def().unwrap(),
1070 NameBindingKind::Import { binding, .. } => binding.def(),
1071 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1072 NameBindingKind::Ambiguity { .. } => Def::Err,
1076 fn def_ignoring_ambiguity(&self) -> Def {
1078 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1079 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1084 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Rc<SyntaxExtension> {
1085 resolver.get_macro(self.def_ignoring_ambiguity())
1088 // We sometimes need to treat variants as `pub` for backwards compatibility
1089 fn pseudo_vis(&self) -> ty::Visibility {
1090 if self.is_variant() { ty::Visibility::Public } else { self.vis }
1093 fn is_variant(&self) -> bool {
1095 NameBindingKind::Def(Def::Variant(..)) |
1096 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1101 fn is_extern_crate(&self) -> bool {
1103 NameBindingKind::Import {
1104 directive: &ImportDirective {
1105 subclass: ImportDirectiveSubclass::ExternCrate, ..
1112 fn is_import(&self) -> bool {
1114 NameBindingKind::Import { .. } => true,
1119 fn is_glob_import(&self) -> bool {
1121 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1122 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1127 fn is_importable(&self) -> bool {
1129 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1134 fn is_macro_def(&self) -> bool {
1136 NameBindingKind::Def(Def::Macro(..)) => true,
1141 fn descr(&self) -> &'static str {
1142 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1146 /// Interns the names of the primitive types.
1147 struct PrimitiveTypeTable {
1148 primitive_types: FxHashMap<Name, PrimTy>,
1151 impl PrimitiveTypeTable {
1152 fn new() -> PrimitiveTypeTable {
1153 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1155 table.intern("bool", TyBool);
1156 table.intern("char", TyChar);
1157 table.intern("f32", TyFloat(FloatTy::F32));
1158 table.intern("f64", TyFloat(FloatTy::F64));
1159 table.intern("isize", TyInt(IntTy::Is));
1160 table.intern("i8", TyInt(IntTy::I8));
1161 table.intern("i16", TyInt(IntTy::I16));
1162 table.intern("i32", TyInt(IntTy::I32));
1163 table.intern("i64", TyInt(IntTy::I64));
1164 table.intern("i128", TyInt(IntTy::I128));
1165 table.intern("str", TyStr);
1166 table.intern("usize", TyUint(UintTy::Us));
1167 table.intern("u8", TyUint(UintTy::U8));
1168 table.intern("u16", TyUint(UintTy::U16));
1169 table.intern("u32", TyUint(UintTy::U32));
1170 table.intern("u64", TyUint(UintTy::U64));
1171 table.intern("u128", TyUint(UintTy::U128));
1175 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1176 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1180 /// The main resolver class.
1181 pub struct Resolver<'a> {
1182 session: &'a Session,
1184 pub definitions: Definitions,
1186 graph_root: Module<'a>,
1188 prelude: Option<Module<'a>>,
1190 // n.b. This is used only for better diagnostics, not name resolution itself.
1191 has_self: FxHashSet<DefId>,
1193 // Names of fields of an item `DefId` accessible with dot syntax.
1194 // Used for hints during error reporting.
1195 field_names: FxHashMap<DefId, Vec<Name>>,
1197 // All imports known to succeed or fail.
1198 determined_imports: Vec<&'a ImportDirective<'a>>,
1200 // All non-determined imports.
1201 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1203 // The module that represents the current item scope.
1204 current_module: Module<'a>,
1206 // The current set of local scopes for types and values.
1207 // FIXME #4948: Reuse ribs to avoid allocation.
1208 ribs: PerNS<Vec<Rib<'a>>>,
1210 // The current set of local scopes, for labels.
1211 label_ribs: Vec<Rib<'a>>,
1213 // The trait that the current context can refer to.
1214 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1216 // The current self type if inside an impl (used for better errors).
1217 current_self_type: Option<Ty>,
1219 // The idents for the primitive types.
1220 primitive_type_table: PrimitiveTypeTable,
1223 pub freevars: FreevarMap,
1224 freevars_seen: NodeMap<NodeMap<usize>>,
1225 pub export_map: ExportMap,
1226 pub trait_map: TraitMap,
1228 // A map from nodes to anonymous modules.
1229 // Anonymous modules are pseudo-modules that are implicitly created around items
1230 // contained within blocks.
1232 // For example, if we have this:
1240 // There will be an anonymous module created around `g` with the ID of the
1241 // entry block for `f`.
1242 block_map: NodeMap<Module<'a>>,
1243 module_map: FxHashMap<DefId, Module<'a>>,
1244 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1246 pub make_glob_map: bool,
1247 /// Maps imports to the names of items actually imported (this actually maps
1248 /// all imports, but only glob imports are actually interesting).
1249 pub glob_map: GlobMap,
1251 used_imports: FxHashSet<(NodeId, Namespace)>,
1252 pub maybe_unused_trait_imports: NodeSet,
1254 /// privacy errors are delayed until the end in order to deduplicate them
1255 privacy_errors: Vec<PrivacyError<'a>>,
1256 /// ambiguity errors are delayed for deduplication
1257 ambiguity_errors: Vec<AmbiguityError<'a>>,
1258 /// `use` injections are delayed for better placement and deduplication
1259 use_injections: Vec<UseError<'a>>,
1261 gated_errors: FxHashSet<Span>,
1262 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1264 arenas: &'a ResolverArenas<'a>,
1265 dummy_binding: &'a NameBinding<'a>,
1266 use_extern_macros: bool, // true if `#![feature(use_extern_macros)]`
1268 crate_loader: &'a mut CrateLoader,
1269 macro_names: FxHashSet<Ident>,
1270 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1271 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1272 macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
1273 macro_defs: FxHashMap<Mark, DefId>,
1274 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1275 macro_exports: Vec<Export>,
1276 pub whitelisted_legacy_custom_derives: Vec<Name>,
1277 pub found_unresolved_macro: bool,
1279 // List of crate local macros that we need to warn about as being unused.
1280 // Right now this only includes macro_rules! macros, and macros 2.0.
1281 unused_macros: FxHashSet<DefId>,
1283 // Maps the `Mark` of an expansion to its containing module or block.
1284 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1286 // Avoid duplicated errors for "name already defined".
1287 name_already_seen: FxHashMap<Name, Span>,
1289 // If `#![feature(proc_macro)]` is set
1290 proc_macro_enabled: bool,
1292 // A set of procedural macros imported by `#[macro_use]` that have already been warned about
1293 warned_proc_macros: FxHashSet<Name>,
1295 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1297 // This table maps struct IDs into struct constructor IDs,
1298 // it's not used during normal resolution, only for better error reporting.
1299 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1301 // Only used for better errors on `fn(): fn()`
1302 current_type_ascription: Vec<Span>,
1305 pub struct ResolverArenas<'a> {
1306 modules: arena::TypedArena<ModuleData<'a>>,
1307 local_modules: RefCell<Vec<Module<'a>>>,
1308 name_bindings: arena::TypedArena<NameBinding<'a>>,
1309 import_directives: arena::TypedArena<ImportDirective<'a>>,
1310 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1311 invocation_data: arena::TypedArena<InvocationData<'a>>,
1312 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1315 impl<'a> ResolverArenas<'a> {
1316 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1317 let module = self.modules.alloc(module);
1318 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1319 self.local_modules.borrow_mut().push(module);
1323 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1324 self.local_modules.borrow()
1326 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1327 self.name_bindings.alloc(name_binding)
1329 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1330 -> &'a ImportDirective {
1331 self.import_directives.alloc(import_directive)
1333 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1334 self.name_resolutions.alloc(Default::default())
1336 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1337 -> &'a InvocationData<'a> {
1338 self.invocation_data.alloc(expansion_data)
1340 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1341 self.legacy_bindings.alloc(binding)
1345 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1346 fn parent(self, id: DefId) -> Option<DefId> {
1348 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1349 _ => self.session.cstore.def_key(id).parent,
1350 }.map(|index| DefId { index: index, ..id })
1354 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1355 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1356 let namespace = if is_value { ValueNS } else { TypeNS };
1357 let hir::Path { ref segments, span, ref mut def } = *path;
1358 let path: Vec<SpannedIdent> = segments.iter()
1359 .map(|seg| respan(span, Ident::with_empty_ctxt(seg.name)))
1361 match self.resolve_path(&path, Some(namespace), true, span) {
1362 PathResult::Module(module) => *def = module.def().unwrap(),
1363 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1364 *def = path_res.base_def(),
1365 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span) {
1366 PathResult::Failed(span, msg, _) => {
1367 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1371 PathResult::Indeterminate => unreachable!(),
1372 PathResult::Failed(span, msg, _) => {
1373 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
1378 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1379 self.def_map.get(&id).cloned()
1382 fn definitions(&mut self) -> &mut Definitions {
1383 &mut self.definitions
1387 impl<'a> Resolver<'a> {
1388 pub fn new(session: &'a Session,
1391 make_glob_map: MakeGlobMap,
1392 crate_loader: &'a mut CrateLoader,
1393 arenas: &'a ResolverArenas<'a>)
1395 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1396 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1397 let graph_root = arenas.alloc_module(ModuleData {
1398 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1399 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1401 let mut module_map = FxHashMap();
1402 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1404 let mut definitions = Definitions::new();
1405 DefCollector::new(&mut definitions, Mark::root())
1406 .collect_root(crate_name, &session.local_crate_disambiguator().as_str());
1408 let mut invocations = FxHashMap();
1409 invocations.insert(Mark::root(),
1410 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1412 let features = session.features.borrow();
1414 let mut macro_defs = FxHashMap();
1415 macro_defs.insert(Mark::root(), root_def_id);
1422 // The outermost module has def ID 0; this is not reflected in the
1427 has_self: FxHashSet(),
1428 field_names: FxHashMap(),
1430 determined_imports: Vec::new(),
1431 indeterminate_imports: Vec::new(),
1433 current_module: graph_root,
1435 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1436 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1437 macro_ns: Some(vec![Rib::new(ModuleRibKind(graph_root))]),
1439 label_ribs: Vec::new(),
1441 current_trait_ref: None,
1442 current_self_type: None,
1444 primitive_type_table: PrimitiveTypeTable::new(),
1447 freevars: NodeMap(),
1448 freevars_seen: NodeMap(),
1449 export_map: NodeMap(),
1450 trait_map: NodeMap(),
1452 block_map: NodeMap(),
1453 extern_module_map: FxHashMap(),
1455 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1456 glob_map: NodeMap(),
1458 used_imports: FxHashSet(),
1459 maybe_unused_trait_imports: NodeSet(),
1461 privacy_errors: Vec::new(),
1462 ambiguity_errors: Vec::new(),
1463 use_injections: Vec::new(),
1464 gated_errors: FxHashSet(),
1465 disallowed_shadowing: Vec::new(),
1468 dummy_binding: arenas.alloc_name_binding(NameBinding {
1469 kind: NameBindingKind::Def(Def::Err),
1470 expansion: Mark::root(),
1472 vis: ty::Visibility::Public,
1475 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1477 features.use_extern_macros || features.proc_macro || features.decl_macro,
1480 macro_names: FxHashSet(),
1481 global_macros: FxHashMap(),
1482 lexical_macro_resolutions: Vec::new(),
1483 macro_map: FxHashMap(),
1484 macro_exports: Vec::new(),
1487 local_macro_def_scopes: FxHashMap(),
1488 name_already_seen: FxHashMap(),
1489 whitelisted_legacy_custom_derives: Vec::new(),
1490 proc_macro_enabled: features.proc_macro,
1491 warned_proc_macros: FxHashSet(),
1492 potentially_unused_imports: Vec::new(),
1493 struct_constructors: DefIdMap(),
1494 found_unresolved_macro: false,
1495 unused_macros: FxHashSet(),
1496 current_type_ascription: Vec::new(),
1500 pub fn arenas() -> ResolverArenas<'a> {
1502 modules: arena::TypedArena::new(),
1503 local_modules: RefCell::new(Vec::new()),
1504 name_bindings: arena::TypedArena::new(),
1505 import_directives: arena::TypedArena::new(),
1506 name_resolutions: arena::TypedArena::new(),
1507 invocation_data: arena::TypedArena::new(),
1508 legacy_bindings: arena::TypedArena::new(),
1512 fn per_ns<T, F: FnMut(&mut Self, Namespace) -> T>(&mut self, mut f: F) -> PerNS<T> {
1514 type_ns: f(self, TypeNS),
1515 value_ns: f(self, ValueNS),
1516 macro_ns: match self.use_extern_macros {
1517 true => Some(f(self, MacroNS)),
1523 /// Entry point to crate resolution.
1524 pub fn resolve_crate(&mut self, krate: &Crate) {
1525 ImportResolver { resolver: self }.finalize_imports();
1526 self.current_module = self.graph_root;
1527 self.finalize_current_module_macro_resolutions();
1529 visit::walk_crate(self, krate);
1531 check_unused::check_crate(self, krate);
1532 self.report_errors(krate);
1533 self.crate_loader.postprocess(krate);
1540 normal_ancestor_id: DefId,
1544 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1545 self.arenas.alloc_module(module)
1548 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1549 -> bool /* true if an error was reported */ {
1550 match binding.kind {
1551 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1554 directive.used.set(true);
1555 if legacy_self_import {
1556 self.warn_legacy_self_import(directive);
1559 self.used_imports.insert((directive.id, ns));
1560 self.add_to_glob_map(directive.id, ident);
1561 self.record_use(ident, ns, binding, span)
1563 NameBindingKind::Import { .. } => false,
1564 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1565 self.ambiguity_errors.push(AmbiguityError {
1566 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy,
1569 self.record_use(ident, ns, b1, span);
1577 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1578 if self.make_glob_map {
1579 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1583 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1584 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1585 /// `ident` in the first scope that defines it (or None if no scopes define it).
1587 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1588 /// the items are defined in the block. For example,
1591 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1594 /// g(); // This resolves to the local variable `g` since it shadows the item.
1598 /// Invariant: This must only be called during main resolution, not during
1599 /// import resolution.
1600 fn resolve_ident_in_lexical_scope(&mut self,
1605 -> Option<LexicalScopeBinding<'a>> {
1607 ident.ctxt = if ident.name == keywords::SelfType.name() {
1608 SyntaxContext::empty() // FIXME(jseyfried) improve `Self` hygiene
1614 // Walk backwards up the ribs in scope.
1615 let mut module = self.graph_root;
1616 for i in (0 .. self.ribs[ns].len()).rev() {
1617 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1618 // The ident resolves to a type parameter or local variable.
1619 return Some(LexicalScopeBinding::Def(
1620 self.adjust_local_def(ns, i, def, record_used, path_span)
1624 module = match self.ribs[ns][i].kind {
1625 ModuleRibKind(module) => module,
1626 MacroDefinition(def) if def == self.macro_defs[&ident.ctxt.outer()] => {
1627 // If an invocation of this macro created `ident`, give up on `ident`
1628 // and switch to `ident`'s source from the macro definition.
1629 ident.ctxt.remove_mark();
1635 let item = self.resolve_ident_in_module_unadjusted(
1636 module, ident, ns, false, record_used, path_span,
1638 if let Ok(binding) = item {
1639 // The ident resolves to an item.
1640 return Some(LexicalScopeBinding::Item(binding));
1644 ModuleKind::Block(..) => {}, // We can see through blocks
1649 ident.ctxt = ident.ctxt.modern();
1651 module = unwrap_or!(self.hygienic_lexical_parent(module, &mut ident.ctxt), break);
1652 let orig_current_module = self.current_module;
1653 self.current_module = module; // Lexical resolutions can never be a privacy error.
1654 let result = self.resolve_ident_in_module_unadjusted(
1655 module, ident, ns, false, record_used, path_span,
1657 self.current_module = orig_current_module;
1660 Ok(binding) => return Some(LexicalScopeBinding::Item(binding)),
1661 Err(Undetermined) => return None,
1662 Err(Determined) => {}
1666 match self.prelude {
1667 Some(prelude) if !module.no_implicit_prelude => {
1668 self.resolve_ident_in_module_unadjusted(prelude, ident, ns, false, false, path_span)
1669 .ok().map(LexicalScopeBinding::Item)
1675 fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, ctxt: &mut SyntaxContext)
1676 -> Option<Module<'a>> {
1677 if !module.expansion.is_descendant_of(ctxt.outer()) {
1678 return Some(self.macro_def_scope(ctxt.remove_mark()));
1681 if let ModuleKind::Block(..) = module.kind {
1682 return Some(module.parent.unwrap());
1685 let mut module_expansion = module.expansion.modern(); // for backward compatibility
1686 while let Some(parent) = module.parent {
1687 let parent_expansion = parent.expansion.modern();
1688 if module_expansion.is_descendant_of(parent_expansion) &&
1689 parent_expansion != module_expansion {
1690 return if parent_expansion.is_descendant_of(ctxt.outer()) {
1697 module_expansion = parent_expansion;
1703 fn resolve_ident_in_module(&mut self,
1707 ignore_unresolved_invocations: bool,
1710 -> Result<&'a NameBinding<'a>, Determinacy> {
1711 ident.ctxt = ident.ctxt.modern();
1712 let orig_current_module = self.current_module;
1713 if let Some(def) = ident.ctxt.adjust(module.expansion) {
1714 self.current_module = self.macro_def_scope(def);
1716 let result = self.resolve_ident_in_module_unadjusted(
1717 module, ident, ns, ignore_unresolved_invocations, record_used, span,
1719 self.current_module = orig_current_module;
1723 fn resolve_crate_root(&mut self, mut ctxt: SyntaxContext) -> Module<'a> {
1724 let module = match ctxt.adjust(Mark::root()) {
1725 Some(def) => self.macro_def_scope(def),
1726 None => return self.graph_root,
1728 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1731 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1732 let mut module = self.get_module(module.normal_ancestor_id);
1733 while module.span.ctxt.modern() != *ctxt {
1734 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1735 module = self.get_module(parent.normal_ancestor_id);
1742 // We maintain a list of value ribs and type ribs.
1744 // Simultaneously, we keep track of the current position in the module
1745 // graph in the `current_module` pointer. When we go to resolve a name in
1746 // the value or type namespaces, we first look through all the ribs and
1747 // then query the module graph. When we resolve a name in the module
1748 // namespace, we can skip all the ribs (since nested modules are not
1749 // allowed within blocks in Rust) and jump straight to the current module
1752 // Named implementations are handled separately. When we find a method
1753 // call, we consult the module node to find all of the implementations in
1754 // scope. This information is lazily cached in the module node. We then
1755 // generate a fake "implementation scope" containing all the
1756 // implementations thus found, for compatibility with old resolve pass.
1758 fn with_scope<F>(&mut self, id: NodeId, f: F)
1759 where F: FnOnce(&mut Resolver)
1761 let id = self.definitions.local_def_id(id);
1762 let module = self.module_map.get(&id).cloned(); // clones a reference
1763 if let Some(module) = module {
1764 // Move down in the graph.
1765 let orig_module = replace(&mut self.current_module, module);
1766 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
1767 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
1769 self.finalize_current_module_macro_resolutions();
1772 self.current_module = orig_module;
1773 self.ribs[ValueNS].pop();
1774 self.ribs[TypeNS].pop();
1780 /// Searches the current set of local scopes for labels.
1781 /// Stops after meeting a closure.
1782 fn search_label(&self, mut ident: Ident) -> Option<Def> {
1783 for rib in self.label_ribs.iter().rev() {
1786 // If an invocation of this macro created `ident`, give up on `ident`
1787 // and switch to `ident`'s source from the macro definition.
1788 MacroDefinition(def) => {
1789 if def == self.macro_defs[&ident.ctxt.outer()] {
1790 ident.ctxt.remove_mark();
1794 // Do not resolve labels across function boundary
1798 let result = rib.bindings.get(&ident).cloned();
1799 if result.is_some() {
1806 fn resolve_item(&mut self, item: &Item) {
1807 let name = item.ident.name;
1809 debug!("(resolving item) resolving {}", name);
1811 self.check_proc_macro_attrs(&item.attrs);
1814 ItemKind::Enum(_, ref generics) |
1815 ItemKind::Ty(_, ref generics) |
1816 ItemKind::Struct(_, ref generics) |
1817 ItemKind::Union(_, ref generics) |
1818 ItemKind::Fn(.., ref generics, _) => {
1819 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
1820 |this| visit::walk_item(this, item));
1823 ItemKind::DefaultImpl(_, ref trait_ref) => {
1824 self.with_optional_trait_ref(Some(trait_ref), |this, _| {
1825 // Resolve type arguments in trait path
1826 visit::walk_trait_ref(this, trait_ref);
1829 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
1830 self.resolve_implementation(generics,
1836 ItemKind::Trait(_, ref generics, ref bounds, ref trait_items) => {
1837 // Create a new rib for the trait-wide type parameters.
1838 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
1839 let local_def_id = this.definitions.local_def_id(item.id);
1840 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
1841 this.visit_generics(generics);
1842 walk_list!(this, visit_ty_param_bound, bounds);
1844 for trait_item in trait_items {
1845 this.check_proc_macro_attrs(&trait_item.attrs);
1847 match trait_item.node {
1848 TraitItemKind::Const(ref ty, ref default) => {
1851 // Only impose the restrictions of
1852 // ConstRibKind for an actual constant
1853 // expression in a provided default.
1854 if let Some(ref expr) = *default{
1855 this.with_constant_rib(|this| {
1856 this.visit_expr(expr);
1860 TraitItemKind::Method(ref sig, _) => {
1861 let type_parameters =
1862 HasTypeParameters(&sig.generics,
1863 MethodRibKind(!sig.decl.has_self()));
1864 this.with_type_parameter_rib(type_parameters, |this| {
1865 visit::walk_trait_item(this, trait_item)
1868 TraitItemKind::Type(..) => {
1869 this.with_type_parameter_rib(NoTypeParameters, |this| {
1870 visit::walk_trait_item(this, trait_item)
1873 TraitItemKind::Macro(_) => panic!("unexpanded macro in resolve!"),
1880 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
1881 self.with_scope(item.id, |this| {
1882 visit::walk_item(this, item);
1886 ItemKind::Static(ref ty, _, ref expr) |
1887 ItemKind::Const(ref ty, ref expr) => {
1888 self.with_item_rib(|this| {
1890 this.with_constant_rib(|this| {
1891 this.visit_expr(expr);
1896 ItemKind::Use(ref view_path) => {
1897 match view_path.node {
1898 ast::ViewPathList(ref prefix, ref items) if items.is_empty() => {
1899 // Resolve prefix of an import with empty braces (issue #28388).
1900 self.smart_resolve_path(item.id, None, prefix, PathSource::ImportPrefix);
1906 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_)=> {
1907 // do nothing, these are just around to be encoded
1910 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
1914 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
1915 where F: FnOnce(&mut Resolver)
1917 match type_parameters {
1918 HasTypeParameters(generics, rib_kind) => {
1919 let mut function_type_rib = Rib::new(rib_kind);
1920 let mut seen_bindings = FxHashMap();
1921 for type_parameter in &generics.ty_params {
1922 let ident = type_parameter.ident.modern();
1923 debug!("with_type_parameter_rib: {}", type_parameter.id);
1925 if seen_bindings.contains_key(&ident) {
1926 let span = seen_bindings.get(&ident).unwrap();
1928 ResolutionError::NameAlreadyUsedInTypeParameterList(ident.name, span);
1929 resolve_error(self, type_parameter.span, err);
1931 seen_bindings.entry(ident).or_insert(type_parameter.span);
1933 // plain insert (no renaming)
1934 let def_id = self.definitions.local_def_id(type_parameter.id);
1935 let def = Def::TyParam(def_id);
1936 function_type_rib.bindings.insert(ident, def);
1937 self.record_def(type_parameter.id, PathResolution::new(def));
1939 self.ribs[TypeNS].push(function_type_rib);
1942 NoTypeParameters => {
1949 if let HasTypeParameters(..) = type_parameters {
1950 self.ribs[TypeNS].pop();
1954 fn with_label_rib<F>(&mut self, f: F)
1955 where F: FnOnce(&mut Resolver)
1957 self.label_ribs.push(Rib::new(NormalRibKind));
1959 self.label_ribs.pop();
1962 fn with_item_rib<F>(&mut self, f: F)
1963 where F: FnOnce(&mut Resolver)
1965 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
1966 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
1968 self.ribs[TypeNS].pop();
1969 self.ribs[ValueNS].pop();
1972 fn with_constant_rib<F>(&mut self, f: F)
1973 where F: FnOnce(&mut Resolver)
1975 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
1977 self.ribs[ValueNS].pop();
1980 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
1981 where F: FnOnce(&mut Resolver) -> T
1983 // Handle nested impls (inside fn bodies)
1984 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
1985 let result = f(self);
1986 self.current_self_type = previous_value;
1990 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
1991 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
1993 let mut new_val = None;
1994 let mut new_id = None;
1995 if let Some(trait_ref) = opt_trait_ref {
1996 let path: Vec<_> = trait_ref.path.segments.iter()
1997 .map(|seg| respan(seg.span, seg.identifier))
1999 let def = self.smart_resolve_path_fragment(trait_ref.ref_id,
2002 trait_ref.path.span,
2003 trait_ref.path.segments.last().unwrap().span,
2006 if def != Def::Err {
2007 new_id = Some(def.def_id());
2008 let span = trait_ref.path.span;
2009 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span) {
2010 new_val = Some((module, trait_ref.clone()));
2014 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2015 let result = f(self, new_id);
2016 self.current_trait_ref = original_trait_ref;
2020 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2021 where F: FnOnce(&mut Resolver)
2023 let mut self_type_rib = Rib::new(NormalRibKind);
2025 // plain insert (no renaming, types are not currently hygienic....)
2026 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2027 self.ribs[TypeNS].push(self_type_rib);
2029 self.ribs[TypeNS].pop();
2032 fn resolve_implementation(&mut self,
2033 generics: &Generics,
2034 opt_trait_reference: &Option<TraitRef>,
2037 impl_items: &[ImplItem]) {
2038 // If applicable, create a rib for the type parameters.
2039 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2040 // Dummy self type for better errors if `Self` is used in the trait path.
2041 this.with_self_rib(Def::SelfTy(None, None), |this| {
2042 // Resolve the trait reference, if necessary.
2043 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2044 let item_def_id = this.definitions.local_def_id(item_id);
2045 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2046 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2047 // Resolve type arguments in trait path
2048 visit::walk_trait_ref(this, trait_ref);
2050 // Resolve the self type.
2051 this.visit_ty(self_type);
2052 // Resolve the type parameters.
2053 this.visit_generics(generics);
2054 this.with_current_self_type(self_type, |this| {
2055 for impl_item in impl_items {
2056 this.check_proc_macro_attrs(&impl_item.attrs);
2057 this.resolve_visibility(&impl_item.vis);
2058 match impl_item.node {
2059 ImplItemKind::Const(..) => {
2060 // If this is a trait impl, ensure the const
2062 this.check_trait_item(impl_item.ident,
2065 |n, s| ResolutionError::ConstNotMemberOfTrait(n, s));
2066 visit::walk_impl_item(this, impl_item);
2068 ImplItemKind::Method(ref sig, _) => {
2069 // If this is a trait impl, ensure the method
2071 this.check_trait_item(impl_item.ident,
2074 |n, s| ResolutionError::MethodNotMemberOfTrait(n, s));
2076 // We also need a new scope for the method-
2077 // specific type parameters.
2078 let type_parameters =
2079 HasTypeParameters(&sig.generics,
2080 MethodRibKind(!sig.decl.has_self()));
2081 this.with_type_parameter_rib(type_parameters, |this| {
2082 visit::walk_impl_item(this, impl_item);
2085 ImplItemKind::Type(ref ty) => {
2086 // If this is a trait impl, ensure the type
2088 this.check_trait_item(impl_item.ident,
2091 |n, s| ResolutionError::TypeNotMemberOfTrait(n, s));
2095 ImplItemKind::Macro(_) =>
2096 panic!("unexpanded macro in resolve!"),
2106 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2107 where F: FnOnce(Name, &str) -> ResolutionError
2109 // If there is a TraitRef in scope for an impl, then the method must be in the
2111 if let Some((module, _)) = self.current_trait_ref {
2112 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2113 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2114 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2119 fn resolve_local(&mut self, local: &Local) {
2120 // Resolve the type.
2121 walk_list!(self, visit_ty, &local.ty);
2123 // Resolve the initializer.
2124 walk_list!(self, visit_expr, &local.init);
2126 // Resolve the pattern.
2127 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2130 // build a map from pattern identifiers to binding-info's.
2131 // this is done hygienically. This could arise for a macro
2132 // that expands into an or-pattern where one 'x' was from the
2133 // user and one 'x' came from the macro.
2134 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2135 let mut binding_map = FxHashMap();
2137 pat.walk(&mut |pat| {
2138 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2139 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2140 Some(Def::Local(..)) => true,
2143 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2144 binding_map.insert(ident.node, binding_info);
2153 // check that all of the arms in an or-pattern have exactly the
2154 // same set of bindings, with the same binding modes for each.
2155 fn check_consistent_bindings(&mut self, arm: &Arm) {
2156 if arm.pats.is_empty() {
2160 let mut missing_vars = FxHashMap();
2161 let mut inconsistent_vars = FxHashMap();
2162 for (i, p) in arm.pats.iter().enumerate() {
2163 let map_i = self.binding_mode_map(&p);
2165 for (j, q) in arm.pats.iter().enumerate() {
2170 let map_j = self.binding_mode_map(&q);
2171 for (&key, &binding_i) in &map_i {
2172 if map_j.len() == 0 { // Account for missing bindings when
2173 let binding_error = missing_vars // map_j has none.
2175 .or_insert(BindingError {
2177 origin: BTreeSet::new(),
2178 target: BTreeSet::new(),
2180 binding_error.origin.insert(binding_i.span);
2181 binding_error.target.insert(q.span);
2183 for (&key_j, &binding_j) in &map_j {
2184 match map_i.get(&key_j) {
2185 None => { // missing binding
2186 let binding_error = missing_vars
2188 .or_insert(BindingError {
2190 origin: BTreeSet::new(),
2191 target: BTreeSet::new(),
2193 binding_error.origin.insert(binding_j.span);
2194 binding_error.target.insert(p.span);
2196 Some(binding_i) => { // check consistent binding
2197 if binding_i.binding_mode != binding_j.binding_mode {
2200 .or_insert((binding_j.span, binding_i.span));
2208 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2209 missing_vars.sort();
2210 for (_, v) in missing_vars {
2212 *v.origin.iter().next().unwrap(),
2213 ResolutionError::VariableNotBoundInPattern(v));
2215 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2216 inconsistent_vars.sort();
2217 for (name, v) in inconsistent_vars {
2218 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2222 fn resolve_arm(&mut self, arm: &Arm) {
2223 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2225 let mut bindings_list = FxHashMap();
2226 for pattern in &arm.pats {
2227 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2230 // This has to happen *after* we determine which
2231 // pat_idents are variants
2232 self.check_consistent_bindings(arm);
2234 walk_list!(self, visit_expr, &arm.guard);
2235 self.visit_expr(&arm.body);
2237 self.ribs[ValueNS].pop();
2240 fn resolve_block(&mut self, block: &Block) {
2241 debug!("(resolving block) entering block");
2242 // Move down in the graph, if there's an anonymous module rooted here.
2243 let orig_module = self.current_module;
2244 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2246 let mut num_macro_definition_ribs = 0;
2247 if let Some(anonymous_module) = anonymous_module {
2248 debug!("(resolving block) found anonymous module, moving down");
2249 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2250 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2251 self.current_module = anonymous_module;
2252 self.finalize_current_module_macro_resolutions();
2254 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2257 // Descend into the block.
2258 for stmt in &block.stmts {
2259 if let ast::StmtKind::Item(ref item) = stmt.node {
2260 if let ast::ItemKind::MacroDef(..) = item.node {
2261 num_macro_definition_ribs += 1;
2262 let def = self.definitions.local_def_id(item.id);
2263 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2264 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2268 self.visit_stmt(stmt);
2272 self.current_module = orig_module;
2273 for _ in 0 .. num_macro_definition_ribs {
2274 self.ribs[ValueNS].pop();
2275 self.label_ribs.pop();
2277 self.ribs[ValueNS].pop();
2278 if let Some(_) = anonymous_module {
2279 self.ribs[TypeNS].pop();
2281 debug!("(resolving block) leaving block");
2284 fn fresh_binding(&mut self,
2285 ident: &SpannedIdent,
2287 outer_pat_id: NodeId,
2288 pat_src: PatternSource,
2289 bindings: &mut FxHashMap<Ident, NodeId>)
2291 // Add the binding to the local ribs, if it
2292 // doesn't already exist in the bindings map. (We
2293 // must not add it if it's in the bindings map
2294 // because that breaks the assumptions later
2295 // passes make about or-patterns.)
2296 let mut def = Def::Local(self.definitions.local_def_id(pat_id));
2297 match bindings.get(&ident.node).cloned() {
2298 Some(id) if id == outer_pat_id => {
2299 // `Variant(a, a)`, error
2303 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2304 &ident.node.name.as_str())
2307 Some(..) if pat_src == PatternSource::FnParam => {
2308 // `fn f(a: u8, a: u8)`, error
2312 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2313 &ident.node.name.as_str())
2316 Some(..) if pat_src == PatternSource::Match => {
2317 // `Variant1(a) | Variant2(a)`, ok
2318 // Reuse definition from the first `a`.
2319 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident.node];
2322 span_bug!(ident.span, "two bindings with the same name from \
2323 unexpected pattern source {:?}", pat_src);
2326 // A completely fresh binding, add to the lists if it's valid.
2327 if ident.node.name != keywords::Invalid.name() {
2328 bindings.insert(ident.node, outer_pat_id);
2329 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident.node, def);
2334 PathResolution::new(def)
2337 fn resolve_pattern(&mut self,
2339 pat_src: PatternSource,
2340 // Maps idents to the node ID for the
2341 // outermost pattern that binds them.
2342 bindings: &mut FxHashMap<Ident, NodeId>) {
2343 // Visit all direct subpatterns of this pattern.
2344 let outer_pat_id = pat.id;
2345 pat.walk(&mut |pat| {
2347 PatKind::Ident(bmode, ref ident, ref opt_pat) => {
2348 // First try to resolve the identifier as some existing
2349 // entity, then fall back to a fresh binding.
2350 let binding = self.resolve_ident_in_lexical_scope(ident.node, ValueNS,
2352 .and_then(LexicalScopeBinding::item);
2353 let resolution = binding.map(NameBinding::def).and_then(|def| {
2354 let ivmode = BindingMode::ByValue(Mutability::Immutable);
2355 let always_binding = !pat_src.is_refutable() || opt_pat.is_some() ||
2358 Def::StructCtor(_, CtorKind::Const) |
2359 Def::VariantCtor(_, CtorKind::Const) |
2360 Def::Const(..) if !always_binding => {
2361 // A unit struct/variant or constant pattern.
2362 self.record_use(ident.node, ValueNS, binding.unwrap(), ident.span);
2363 Some(PathResolution::new(def))
2365 Def::StructCtor(..) | Def::VariantCtor(..) |
2366 Def::Const(..) | Def::Static(..) => {
2367 // A fresh binding that shadows something unacceptable.
2371 ResolutionError::BindingShadowsSomethingUnacceptable(
2372 pat_src.descr(), ident.node.name, binding.unwrap())
2376 Def::Local(..) | Def::Upvar(..) | Def::Fn(..) | Def::Err => {
2377 // These entities are explicitly allowed
2378 // to be shadowed by fresh bindings.
2382 span_bug!(ident.span, "unexpected definition for an \
2383 identifier in pattern: {:?}", def);
2386 }).unwrap_or_else(|| {
2387 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2390 self.record_def(pat.id, resolution);
2393 PatKind::TupleStruct(ref path, ..) => {
2394 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2397 PatKind::Path(ref qself, ref path) => {
2398 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2401 PatKind::Struct(ref path, ..) => {
2402 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2410 visit::walk_pat(self, pat);
2413 // High-level and context dependent path resolution routine.
2414 // Resolves the path and records the resolution into definition map.
2415 // If resolution fails tries several techniques to find likely
2416 // resolution candidates, suggest imports or other help, and report
2417 // errors in user friendly way.
2418 fn smart_resolve_path(&mut self,
2420 qself: Option<&QSelf>,
2424 let segments = &path.segments.iter()
2425 .map(|seg| respan(seg.span, seg.identifier))
2426 .collect::<Vec<_>>();
2427 let ident_span = path.segments.last().map_or(path.span, |seg| seg.span);
2428 self.smart_resolve_path_fragment(id, qself, segments, path.span, ident_span, source)
2431 fn smart_resolve_path_fragment(&mut self,
2433 qself: Option<&QSelf>,
2434 path: &[SpannedIdent],
2439 let ns = source.namespace();
2440 let is_expected = &|def| source.is_expected(def);
2441 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2443 // Base error is amended with one short label and possibly some longer helps/notes.
2444 let report_errors = |this: &mut Self, def: Option<Def>| {
2445 // Make the base error.
2446 let expected = source.descr_expected();
2447 let path_str = names_to_string(path);
2448 let code = source.error_code(def.is_some());
2449 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2450 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2451 format!("not a {}", expected), span)
2453 let item_str = path[path.len() - 1].node;
2454 let item_span = path[path.len() - 1].span;
2455 let (mod_prefix, mod_str) = if path.len() == 1 {
2456 (format!(""), format!("this scope"))
2457 } else if path.len() == 2 && path[0].node.name == keywords::CrateRoot.name() {
2458 (format!(""), format!("the crate root"))
2460 let mod_path = &path[..path.len() - 1];
2461 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS), false, span) {
2462 PathResult::Module(module) => module.def(),
2464 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2465 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2467 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2468 format!("not found in {}", mod_str), item_span)
2470 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2472 // Emit special messages for unresolved `Self` and `self`.
2473 if is_self_type(path, ns) {
2474 __diagnostic_used!(E0411);
2475 err.code("E0411".into());
2476 err.span_label(span, "`Self` is only available in traits and impls");
2477 return (err, Vec::new());
2479 if is_self_value(path, ns) {
2480 __diagnostic_used!(E0424);
2481 err.code("E0424".into());
2482 err.span_label(span, format!("`self` value is only available in \
2483 methods with `self` parameter"));
2484 return (err, Vec::new());
2487 // Try to lookup the name in more relaxed fashion for better error reporting.
2488 let ident = *path.last().unwrap();
2489 let candidates = this.lookup_import_candidates(ident.node.name, ns, is_expected);
2490 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2491 let enum_candidates =
2492 this.lookup_import_candidates(ident.node.name, ns, is_enum_variant);
2493 let mut enum_candidates = enum_candidates.iter()
2494 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2495 enum_candidates.sort();
2496 for (sp, variant_path, enum_path) in enum_candidates {
2498 let msg = format!("there is an enum variant `{}`, \
2504 err.span_suggestion(span, "you can try using the variant's enum",
2509 if path.len() == 1 && this.self_type_is_available(span) {
2510 if let Some(candidate) = this.lookup_assoc_candidate(ident.node, ns, is_expected) {
2511 let self_is_available = this.self_value_is_available(path[0].node.ctxt, span);
2513 AssocSuggestion::Field => {
2514 err.span_suggestion(span, "try",
2515 format!("self.{}", path_str));
2516 if !self_is_available {
2517 err.span_label(span, format!("`self` value is only available in \
2518 methods with `self` parameter"));
2521 AssocSuggestion::MethodWithSelf if self_is_available => {
2522 err.span_suggestion(span, "try",
2523 format!("self.{}", path_str));
2525 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2526 err.span_suggestion(span, "try",
2527 format!("Self::{}", path_str));
2530 return (err, candidates);
2534 let mut levenshtein_worked = false;
2537 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2538 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2539 levenshtein_worked = true;
2542 // Try context dependent help if relaxed lookup didn't work.
2543 if let Some(def) = def {
2544 match (def, source) {
2545 (Def::Macro(..), _) => {
2546 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2547 return (err, candidates);
2549 (Def::TyAlias(..), PathSource::Trait) => {
2550 err.span_label(span, "type aliases cannot be used for traits");
2551 return (err, candidates);
2553 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2554 ExprKind::Field(_, ident) => {
2555 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2556 path_str, ident.node));
2557 return (err, candidates);
2559 ExprKind::MethodCall(ref segment, ..) => {
2560 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2561 path_str, segment.identifier));
2562 return (err, candidates);
2566 _ if ns == ValueNS && is_struct_like(def) => {
2567 if let Def::Struct(def_id) = def {
2568 if let Some((ctor_def, ctor_vis))
2569 = this.struct_constructors.get(&def_id).cloned() {
2570 if is_expected(ctor_def) && !this.is_accessible(ctor_vis) {
2571 err.span_label(span, format!("constructor is not visible \
2572 here due to private fields"));
2576 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2578 return (err, candidates);
2585 if !levenshtein_worked {
2586 err.span_label(base_span, fallback_label);
2587 this.type_ascription_suggestion(&mut err, base_span);
2591 let report_errors = |this: &mut Self, def: Option<Def>| {
2592 let (err, candidates) = report_errors(this, def);
2593 let def_id = this.current_module.normal_ancestor_id;
2594 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
2595 let better = def.is_some();
2596 this.use_injections.push(UseError { err, candidates, node_id, better });
2597 err_path_resolution()
2600 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
2601 source.defer_to_typeck(),
2602 source.global_by_default()) {
2603 Some(resolution) if resolution.unresolved_segments() == 0 => {
2604 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
2607 // Add a temporary hack to smooth the transition to new struct ctor
2608 // visibility rules. See #38932 for more details.
2610 if let Def::Struct(def_id) = resolution.base_def() {
2611 if let Some((ctor_def, ctor_vis))
2612 = self.struct_constructors.get(&def_id).cloned() {
2613 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
2614 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
2615 self.session.buffer_lint(lint, id, span,
2616 "private struct constructors are not usable through \
2617 reexports in outer modules",
2619 res = Some(PathResolution::new(ctor_def));
2624 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
2627 Some(resolution) if source.defer_to_typeck() => {
2628 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
2629 // or `<T>::A::B`. If `B` should be resolved in value namespace then
2630 // it needs to be added to the trait map.
2632 let item_name = path.last().unwrap().node;
2633 let traits = self.get_traits_containing_item(item_name, ns);
2634 self.trait_map.insert(id, traits);
2638 _ => report_errors(self, None)
2641 if let PathSource::TraitItem(..) = source {} else {
2642 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
2643 self.record_def(id, resolution);
2648 fn type_ascription_suggestion(&self,
2649 err: &mut DiagnosticBuilder,
2651 debug!("type_ascription_suggetion {:?}", base_span);
2652 let cm = self.session.codemap();
2653 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
2654 if let Some(sp) = self.current_type_ascription.last() {
2656 loop { // try to find the `:`, bail on first non-':'/non-whitespace
2657 sp = sp.next_point();
2658 if let Ok(snippet) = cm.span_to_snippet(sp.to(sp.next_point())) {
2659 debug!("snippet {:?}", snippet);
2660 let line_sp = cm.lookup_char_pos(sp.hi).line;
2661 let line_base_sp = cm.lookup_char_pos(base_span.lo).line;
2662 debug!("{:?} {:?}", line_sp, line_base_sp);
2664 err.span_label(base_span,
2665 "expecting a type here because of type ascription");
2666 if line_sp != line_base_sp {
2667 err.span_suggestion_short(sp,
2668 "did you mean to use `;` here instead?",
2672 } else if snippet.trim().len() != 0 {
2673 debug!("tried to find type ascription `:` token, couldn't find it");
2683 fn self_type_is_available(&mut self, span: Span) -> bool {
2684 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
2685 TypeNS, false, span);
2686 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2689 fn self_value_is_available(&mut self, ctxt: SyntaxContext, span: Span) -> bool {
2690 let ident = Ident { name: keywords::SelfValue.name(), ctxt: ctxt };
2691 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, span);
2692 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
2695 // Resolve in alternative namespaces if resolution in the primary namespace fails.
2696 fn resolve_qpath_anywhere(&mut self,
2698 qself: Option<&QSelf>,
2699 path: &[SpannedIdent],
2700 primary_ns: Namespace,
2702 defer_to_typeck: bool,
2703 global_by_default: bool)
2704 -> Option<PathResolution> {
2705 let mut fin_res = None;
2706 // FIXME: can't resolve paths in macro namespace yet, macros are
2707 // processed by the little special hack below.
2708 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
2709 if i == 0 || ns != primary_ns {
2710 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
2711 // If defer_to_typeck, then resolution > no resolution,
2712 // otherwise full resolution > partial resolution > no resolution.
2713 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
2715 res => if fin_res.is_none() { fin_res = res },
2719 let is_global = self.global_macros.get(&path[0].node.name).cloned()
2720 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
2721 if primary_ns != MacroNS && (is_global ||
2722 self.macro_names.contains(&path[0].node.modern())) {
2723 // Return some dummy definition, it's enough for error reporting.
2725 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
2731 /// Handles paths that may refer to associated items.
2732 fn resolve_qpath(&mut self,
2734 qself: Option<&QSelf>,
2735 path: &[SpannedIdent],
2738 global_by_default: bool)
2739 -> Option<PathResolution> {
2740 if let Some(qself) = qself {
2741 if qself.position == 0 {
2742 // FIXME: Create some fake resolution that can't possibly be a type.
2743 return Some(PathResolution::with_unresolved_segments(
2744 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
2747 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
2748 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
2749 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
2750 span, span, PathSource::TraitItem(ns));
2751 return Some(PathResolution::with_unresolved_segments(
2752 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
2756 let result = match self.resolve_path(&path, Some(ns), true, span) {
2757 PathResult::NonModule(path_res) => path_res,
2758 PathResult::Module(module) if !module.is_normal() => {
2759 PathResolution::new(module.def().unwrap())
2761 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
2762 // don't report an error right away, but try to fallback to a primitive type.
2763 // So, we are still able to successfully resolve something like
2765 // use std::u8; // bring module u8 in scope
2766 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
2767 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
2768 // // not to non-existent std::u8::max_value
2771 // Such behavior is required for backward compatibility.
2772 // The same fallback is used when `a` resolves to nothing.
2773 PathResult::Module(..) | PathResult::Failed(..)
2774 if (ns == TypeNS || path.len() > 1) &&
2775 self.primitive_type_table.primitive_types
2776 .contains_key(&path[0].node.name) => {
2777 let prim = self.primitive_type_table.primitive_types[&path[0].node.name];
2779 TyUint(UintTy::U128) | TyInt(IntTy::I128) => {
2780 if !self.session.features.borrow().i128_type {
2781 emit_feature_err(&self.session.parse_sess,
2782 "i128_type", span, GateIssue::Language,
2783 "128-bit type is unstable");
2789 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
2791 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
2792 PathResult::Failed(span, msg, false) => {
2793 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
2794 err_path_resolution()
2796 PathResult::Failed(..) => return None,
2797 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
2800 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
2801 path[0].node.name != keywords::CrateRoot.name() &&
2802 path[0].node.name != keywords::DollarCrate.name() {
2803 let unqualified_result = {
2804 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span) {
2805 PathResult::NonModule(path_res) => path_res.base_def(),
2806 PathResult::Module(module) => module.def().unwrap(),
2807 _ => return Some(result),
2810 if result.base_def() == unqualified_result {
2811 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
2812 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
2819 fn resolve_path(&mut self,
2820 path: &[SpannedIdent],
2821 opt_ns: Option<Namespace>, // `None` indicates a module path
2825 let mut module = None;
2826 let mut allow_super = true;
2828 for (i, &ident) in path.iter().enumerate() {
2829 debug!("resolve_path ident {} {:?}", i, ident);
2830 let is_last = i == path.len() - 1;
2831 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2833 if i == 0 && ns == TypeNS && ident.node.name == keywords::SelfValue.name() {
2834 let mut ctxt = ident.node.ctxt.modern();
2835 module = Some(self.resolve_self(&mut ctxt, self.current_module));
2837 } else if allow_super && ns == TypeNS && ident.node.name == keywords::Super.name() {
2838 let mut ctxt = ident.node.ctxt.modern();
2839 let self_module = match i {
2840 0 => self.resolve_self(&mut ctxt, self.current_module),
2841 _ => module.unwrap(),
2843 if let Some(parent) = self_module.parent {
2844 module = Some(self.resolve_self(&mut ctxt, parent));
2847 let msg = "There are too many initial `super`s.".to_string();
2848 return PathResult::Failed(ident.span, msg, false);
2851 allow_super = false;
2853 if i == 0 && ns == TypeNS && ident.node.name == keywords::CrateRoot.name() {
2854 module = Some(self.resolve_crate_root(ident.node.ctxt.modern()));
2856 } else if i == 0 && ns == TypeNS && ident.node.name == keywords::DollarCrate.name() {
2857 module = Some(self.resolve_crate_root(ident.node.ctxt));
2861 let binding = if let Some(module) = module {
2862 self.resolve_ident_in_module(module, ident.node, ns, false, record_used, path_span)
2863 } else if opt_ns == Some(MacroNS) {
2864 self.resolve_lexical_macro_path_segment(ident.node, ns, record_used, path_span)
2865 .map(MacroBinding::binding)
2867 match self.resolve_ident_in_lexical_scope(ident.node, ns, record_used, path_span) {
2868 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2869 Some(LexicalScopeBinding::Def(def))
2870 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
2871 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2875 _ => Err(if record_used { Determined } else { Undetermined }),
2881 let def = binding.def();
2882 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
2883 if let Some(next_module) = binding.module() {
2884 module = Some(next_module);
2885 } else if def == Def::Err {
2886 return PathResult::NonModule(err_path_resolution());
2887 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2888 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2889 def, path.len() - i - 1
2892 return PathResult::Failed(ident.span,
2893 format!("Not a module `{}`", ident.node),
2897 Err(Undetermined) => return PathResult::Indeterminate,
2898 Err(Determined) => {
2899 if let Some(module) = module {
2900 if opt_ns.is_some() && !module.is_normal() {
2901 return PathResult::NonModule(PathResolution::with_unresolved_segments(
2902 module.def().unwrap(), path.len() - i
2906 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
2907 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
2908 let mut candidates =
2909 self.lookup_import_candidates(ident.node.name, TypeNS, is_mod);
2910 candidates.sort_by_key(|c| (c.path.segments.len(), c.path.to_string()));
2911 if let Some(candidate) = candidates.get(0) {
2912 format!("Did you mean `{}`?", candidate.path)
2914 format!("Maybe a missing `extern crate {};`?", ident.node)
2917 format!("Use of undeclared type or module `{}`", ident.node)
2919 format!("Could not find `{}` in `{}`", ident.node, path[i - 1].node)
2921 return PathResult::Failed(ident.span, msg, is_last);
2926 PathResult::Module(module.unwrap_or(self.graph_root))
2929 // Resolve a local definition, potentially adjusting for closures.
2930 fn adjust_local_def(&mut self,
2935 span: Span) -> Def {
2936 let ribs = &self.ribs[ns][rib_index + 1..];
2938 // An invalid forward use of a type parameter from a previous default.
2939 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
2941 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
2943 assert_eq!(def, Def::Err);
2949 span_bug!(span, "unexpected {:?} in bindings", def)
2951 Def::Local(def_id) => {
2954 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
2955 ForwardTyParamBanRibKind => {
2956 // Nothing to do. Continue.
2958 ClosureRibKind(function_id) => {
2960 let node_id = self.definitions.as_local_node_id(def_id).unwrap();
2962 let seen = self.freevars_seen
2964 .or_insert_with(|| NodeMap());
2965 if let Some(&index) = seen.get(&node_id) {
2966 def = Def::Upvar(def_id, index, function_id);
2969 let vec = self.freevars
2971 .or_insert_with(|| vec![]);
2972 let depth = vec.len();
2973 def = Def::Upvar(def_id, depth, function_id);
2980 seen.insert(node_id, depth);
2983 ItemRibKind | MethodRibKind(_) => {
2984 // This was an attempt to access an upvar inside a
2985 // named function item. This is not allowed, so we
2988 resolve_error(self, span,
2989 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
2993 ConstantItemRibKind => {
2994 // Still doesn't deal with upvars
2996 resolve_error(self, span,
2997 ResolutionError::AttemptToUseNonConstantValueInConstant);
3004 Def::TyParam(..) | Def::SelfTy(..) => {
3007 NormalRibKind | MethodRibKind(_) | ClosureRibKind(..) |
3008 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3009 ConstantItemRibKind => {
3010 // Nothing to do. Continue.
3013 // This was an attempt to use a type parameter outside
3016 resolve_error(self, span,
3017 ResolutionError::TypeParametersFromOuterFunction);
3029 fn lookup_assoc_candidate<FilterFn>(&mut self,
3032 filter_fn: FilterFn)
3033 -> Option<AssocSuggestion>
3034 where FilterFn: Fn(Def) -> bool
3036 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3038 TyKind::Path(None, _) => Some(t.id),
3039 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3040 // This doesn't handle the remaining `Ty` variants as they are not
3041 // that commonly the self_type, it might be interesting to provide
3042 // support for those in future.
3047 // Fields are generally expected in the same contexts as locals.
3048 if filter_fn(Def::Local(DefId::local(CRATE_DEF_INDEX))) {
3049 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3050 // Look for a field with the same name in the current self_type.
3051 if let Some(resolution) = self.def_map.get(&node_id) {
3052 match resolution.base_def() {
3053 Def::Struct(did) | Def::Union(did)
3054 if resolution.unresolved_segments() == 0 => {
3055 if let Some(field_names) = self.field_names.get(&did) {
3056 if field_names.iter().any(|&field_name| ident.name == field_name) {
3057 return Some(AssocSuggestion::Field);
3067 // Look for associated items in the current trait.
3068 if let Some((module, _)) = self.current_trait_ref {
3069 if let Ok(binding) =
3070 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3071 let def = binding.def();
3073 return Some(if self.has_self.contains(&def.def_id()) {
3074 AssocSuggestion::MethodWithSelf
3076 AssocSuggestion::AssocItem
3085 fn lookup_typo_candidate<FilterFn>(&mut self,
3086 path: &[SpannedIdent],
3088 filter_fn: FilterFn,
3091 where FilterFn: Fn(Def) -> bool
3093 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3094 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3095 if let Some(binding) = resolution.borrow().binding {
3096 if filter_fn(binding.def()) {
3097 names.push(ident.name);
3103 let mut names = Vec::new();
3104 if path.len() == 1 {
3105 // Search in lexical scope.
3106 // Walk backwards up the ribs in scope and collect candidates.
3107 for rib in self.ribs[ns].iter().rev() {
3108 // Locals and type parameters
3109 for (ident, def) in &rib.bindings {
3110 if filter_fn(*def) {
3111 names.push(ident.name);
3115 if let ModuleRibKind(module) = rib.kind {
3116 // Items from this module
3117 add_module_candidates(module, &mut names);
3119 if let ModuleKind::Block(..) = module.kind {
3120 // We can see through blocks
3122 // Items from the prelude
3123 if let Some(prelude) = self.prelude {
3124 if !module.no_implicit_prelude {
3125 add_module_candidates(prelude, &mut names);
3132 // Add primitive types to the mix
3133 if filter_fn(Def::PrimTy(TyBool)) {
3134 for (name, _) in &self.primitive_type_table.primitive_types {
3139 // Search in module.
3140 let mod_path = &path[..path.len() - 1];
3141 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3143 add_module_candidates(module, &mut names);
3147 let name = path[path.len() - 1].node.name;
3148 // Make sure error reporting is deterministic.
3149 names.sort_by_key(|name| name.as_str());
3150 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3151 Some(found) if found != name => Some(found),
3156 fn with_resolved_label<F>(&mut self, label: Option<SpannedIdent>, id: NodeId, f: F)
3157 where F: FnOnce(&mut Resolver)
3159 if let Some(label) = label {
3160 let def = Def::Label(id);
3161 self.with_label_rib(|this| {
3162 this.label_ribs.last_mut().unwrap().bindings.insert(label.node, def);
3170 fn resolve_labeled_block(&mut self, label: Option<SpannedIdent>, id: NodeId, block: &Block) {
3171 self.with_resolved_label(label, id, |this| this.visit_block(block));
3174 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3175 // First, record candidate traits for this expression if it could
3176 // result in the invocation of a method call.
3178 self.record_candidate_traits_for_expr_if_necessary(expr);
3180 // Next, resolve the node.
3182 ExprKind::Path(ref qself, ref path) => {
3183 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3184 visit::walk_expr(self, expr);
3187 ExprKind::Struct(ref path, ..) => {
3188 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3189 visit::walk_expr(self, expr);
3192 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3193 match self.search_label(label.node) {
3195 self.record_def(expr.id, err_path_resolution());
3198 ResolutionError::UndeclaredLabel(&label.node.name.as_str()));
3200 Some(def @ Def::Label(_)) => {
3201 // Since this def is a label, it is never read.
3202 self.record_def(expr.id, PathResolution::new(def));
3205 span_bug!(expr.span, "label wasn't mapped to a label def!");
3209 // visit `break` argument if any
3210 visit::walk_expr(self, expr);
3213 ExprKind::IfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
3214 self.visit_expr(subexpression);
3216 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3217 self.resolve_pattern(pattern, PatternSource::IfLet, &mut FxHashMap());
3218 self.visit_block(if_block);
3219 self.ribs[ValueNS].pop();
3221 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3224 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3226 ExprKind::While(ref subexpression, ref block, label) => {
3227 self.with_resolved_label(label, expr.id, |this| {
3228 this.visit_expr(subexpression);
3229 this.visit_block(block);
3233 ExprKind::WhileLet(ref pattern, ref subexpression, ref block, label) => {
3234 self.with_resolved_label(label, expr.id, |this| {
3235 this.visit_expr(subexpression);
3236 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3237 this.resolve_pattern(pattern, PatternSource::WhileLet, &mut FxHashMap());
3238 this.visit_block(block);
3239 this.ribs[ValueNS].pop();
3243 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3244 self.visit_expr(subexpression);
3245 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3246 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3248 self.resolve_labeled_block(label, expr.id, block);
3250 self.ribs[ValueNS].pop();
3253 // Equivalent to `visit::walk_expr` + passing some context to children.
3254 ExprKind::Field(ref subexpression, _) => {
3255 self.resolve_expr(subexpression, Some(expr));
3257 ExprKind::MethodCall(ref segment, ref arguments) => {
3258 let mut arguments = arguments.iter();
3259 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3260 for argument in arguments {
3261 self.resolve_expr(argument, None);
3263 self.visit_path_segment(expr.span, segment);
3266 ExprKind::Repeat(ref element, ref count) => {
3267 self.visit_expr(element);
3268 self.with_constant_rib(|this| {
3269 this.visit_expr(count);
3272 ExprKind::Call(ref callee, ref arguments) => {
3273 self.resolve_expr(callee, Some(expr));
3274 for argument in arguments {
3275 self.resolve_expr(argument, None);
3278 ExprKind::Type(ref type_expr, _) => {
3279 self.current_type_ascription.push(type_expr.span);
3280 visit::walk_expr(self, expr);
3281 self.current_type_ascription.pop();
3284 visit::walk_expr(self, expr);
3289 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3291 ExprKind::Field(_, name) => {
3292 // FIXME(#6890): Even though you can't treat a method like a
3293 // field, we need to add any trait methods we find that match
3294 // the field name so that we can do some nice error reporting
3295 // later on in typeck.
3296 let traits = self.get_traits_containing_item(name.node, ValueNS);
3297 self.trait_map.insert(expr.id, traits);
3299 ExprKind::MethodCall(ref segment, ..) => {
3300 debug!("(recording candidate traits for expr) recording traits for {}",
3302 let traits = self.get_traits_containing_item(segment.identifier, ValueNS);
3303 self.trait_map.insert(expr.id, traits);
3311 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
3312 -> Vec<TraitCandidate> {
3313 debug!("(getting traits containing item) looking for '{}'", ident.name);
3315 let mut found_traits = Vec::new();
3316 // Look for the current trait.
3317 if let Some((module, _)) = self.current_trait_ref {
3318 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3319 let def_id = module.def_id().unwrap();
3320 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3324 ident.ctxt = ident.ctxt.modern();
3325 let mut search_module = self.current_module;
3327 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3329 unwrap_or!(self.hygienic_lexical_parent(search_module, &mut ident.ctxt), break);
3332 if let Some(prelude) = self.prelude {
3333 if !search_module.no_implicit_prelude {
3334 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3341 fn get_traits_in_module_containing_item(&mut self,
3345 found_traits: &mut Vec<TraitCandidate>) {
3346 let mut traits = module.traits.borrow_mut();
3347 if traits.is_none() {
3348 let mut collected_traits = Vec::new();
3349 module.for_each_child(|name, ns, binding| {
3350 if ns != TypeNS { return }
3351 if let Def::Trait(_) = binding.def() {
3352 collected_traits.push((name, binding));
3355 *traits = Some(collected_traits.into_boxed_slice());
3358 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3359 let module = binding.module().unwrap();
3360 let mut ident = ident;
3361 if ident.ctxt.glob_adjust(module.expansion, binding.span.ctxt.modern()).is_none() {
3364 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
3366 let import_id = match binding.kind {
3367 NameBindingKind::Import { directive, .. } => {
3368 self.maybe_unused_trait_imports.insert(directive.id);
3369 self.add_to_glob_map(directive.id, trait_name);
3374 let trait_def_id = module.def_id().unwrap();
3375 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3380 /// When name resolution fails, this method can be used to look up candidate
3381 /// entities with the expected name. It allows filtering them using the
3382 /// supplied predicate (which should be used to only accept the types of
3383 /// definitions expected e.g. traits). The lookup spans across all crates.
3385 /// NOTE: The method does not look into imports, but this is not a problem,
3386 /// since we report the definitions (thus, the de-aliased imports).
3387 fn lookup_import_candidates<FilterFn>(&mut self,
3389 namespace: Namespace,
3390 filter_fn: FilterFn)
3391 -> Vec<ImportSuggestion>
3392 where FilterFn: Fn(Def) -> bool
3394 let mut candidates = Vec::new();
3395 let mut worklist = Vec::new();
3396 let mut seen_modules = FxHashSet();
3397 worklist.push((self.graph_root, Vec::new(), false));
3399 while let Some((in_module,
3401 in_module_is_extern)) = worklist.pop() {
3402 self.populate_module_if_necessary(in_module);
3404 // We have to visit module children in deterministic order to avoid
3405 // instabilities in reported imports (#43552).
3406 in_module.for_each_child_stable(|ident, ns, name_binding| {
3407 // avoid imports entirely
3408 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3409 // avoid non-importable candidates as well
3410 if !name_binding.is_importable() { return; }
3412 // collect results based on the filter function
3413 if ident.name == lookup_name && ns == namespace {
3414 if filter_fn(name_binding.def()) {
3416 let mut segms = path_segments.clone();
3417 segms.push(ast::PathSegment::from_ident(ident, name_binding.span));
3419 span: name_binding.span,
3422 // the entity is accessible in the following cases:
3423 // 1. if it's defined in the same crate, it's always
3424 // accessible (since private entities can be made public)
3425 // 2. if it's defined in another crate, it's accessible
3426 // only if both the module is public and the entity is
3427 // declared as public (due to pruning, we don't explore
3428 // outside crate private modules => no need to check this)
3429 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3430 candidates.push(ImportSuggestion { path: path });
3435 // collect submodules to explore
3436 if let Some(module) = name_binding.module() {
3438 let mut path_segments = path_segments.clone();
3439 path_segments.push(ast::PathSegment::from_ident(ident, name_binding.span));
3441 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3442 // add the module to the lookup
3443 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3444 if seen_modules.insert(module.def_id().unwrap()) {
3445 worklist.push((module, path_segments, is_extern));
3455 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
3456 debug!("(recording def) recording {:?} for {}", resolution, node_id);
3457 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
3458 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
3462 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
3464 ast::Visibility::Public => ty::Visibility::Public,
3465 ast::Visibility::Crate(..) => ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
3466 ast::Visibility::Inherited => {
3467 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
3469 ast::Visibility::Restricted { ref path, id } => {
3470 let def = self.smart_resolve_path(id, None, path,
3471 PathSource::Visibility).base_def();
3472 if def == Def::Err {
3473 ty::Visibility::Public
3475 let vis = ty::Visibility::Restricted(def.def_id());
3476 if self.is_accessible(vis) {
3479 self.session.span_err(path.span, "visibilities can only be restricted \
3480 to ancestor modules");
3481 ty::Visibility::Public
3488 fn is_accessible(&self, vis: ty::Visibility) -> bool {
3489 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
3492 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
3493 vis.is_accessible_from(module.normal_ancestor_id, self)
3496 fn report_errors(&mut self, krate: &Crate) {
3497 self.report_shadowing_errors();
3498 self.report_with_use_injections(krate);
3499 let mut reported_spans = FxHashSet();
3501 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
3502 if !reported_spans.insert(span) { continue }
3503 let participle = |binding: &NameBinding| {
3504 if binding.is_import() { "imported" } else { "defined" }
3506 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
3507 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
3508 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
3509 format!("consider adding an explicit import of `{}` to disambiguate", name)
3510 } else if let Def::Macro(..) = b1.def() {
3511 format!("macro-expanded {} do not shadow",
3512 if b1.is_import() { "macro imports" } else { "macros" })
3514 format!("macro-expanded {} do not shadow when used in a macro invocation path",
3515 if b1.is_import() { "imports" } else { "items" })
3518 let id = match b2.kind {
3519 NameBindingKind::Import { directive, .. } => directive.id,
3520 _ => unreachable!(),
3522 let mut span = MultiSpan::from_span(span);
3523 span.push_span_label(b1.span, msg1);
3524 span.push_span_label(b2.span, msg2);
3525 let msg = format!("`{}` is ambiguous", name);
3526 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, &msg);
3529 self.session.struct_span_err(span, &format!("`{}` is ambiguous", name));
3530 err.span_note(b1.span, &msg1);
3532 Def::Macro(..) if b2.span == DUMMY_SP =>
3533 err.note(&format!("`{}` is also a builtin macro", name)),
3534 _ => err.span_note(b2.span, &msg2),
3536 err.note(¬e).emit();
3540 for &PrivacyError(span, name, binding) in &self.privacy_errors {
3541 if !reported_spans.insert(span) { continue }
3542 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
3546 fn report_with_use_injections(&mut self, krate: &Crate) {
3547 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
3548 let mut finder = UsePlacementFinder {
3549 target_module: node_id,
3553 visit::walk_crate(&mut finder, krate);
3554 if !candidates.is_empty() {
3555 let span = finder.span.expect("did not find module");
3556 show_candidates(&mut err, span, &candidates, better, finder.found_use);
3562 fn report_shadowing_errors(&mut self) {
3563 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
3564 self.resolve_legacy_scope(scope, ident, true);
3567 let mut reported_errors = FxHashSet();
3568 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
3569 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
3570 reported_errors.insert((binding.ident, binding.span)) {
3571 let msg = format!("`{}` is already in scope", binding.ident);
3572 self.session.struct_span_err(binding.span, &msg)
3573 .note("macro-expanded `macro_rules!`s may not shadow \
3574 existing macros (see RFC 1560)")
3580 fn report_conflict(&mut self,
3584 new_binding: &NameBinding,
3585 old_binding: &NameBinding) {
3586 // Error on the second of two conflicting names
3587 if old_binding.span.lo > new_binding.span.lo {
3588 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3591 let container = match parent.kind {
3592 ModuleKind::Def(Def::Mod(_), _) => "module",
3593 ModuleKind::Def(Def::Trait(_), _) => "trait",
3594 ModuleKind::Block(..) => "block",
3598 let old_noun = match old_binding.is_import() {
3600 false => "definition",
3603 let new_participle = match new_binding.is_import() {
3608 let (name, span) = (ident.name, new_binding.span);
3610 if let Some(s) = self.name_already_seen.get(&name) {
3616 let old_kind = match (ns, old_binding.module()) {
3617 (ValueNS, _) => "value",
3618 (MacroNS, _) => "macro",
3619 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3620 (TypeNS, Some(module)) if module.is_normal() => "module",
3621 (TypeNS, Some(module)) if module.is_trait() => "trait",
3622 (TypeNS, _) => "type",
3625 let namespace = match ns {
3631 let msg = format!("the name `{}` is defined multiple times", name);
3633 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3634 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3635 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3636 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3637 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3639 _ => match (old_binding.is_import(), new_binding.is_import()) {
3640 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3641 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3642 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3646 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
3651 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3652 if old_binding.span != syntax_pos::DUMMY_SP {
3653 err.span_label(old_binding.span, format!("previous {} of the {} `{}` here",
3654 old_noun, old_kind, name));
3658 self.name_already_seen.insert(name, span);
3661 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
3662 let (id, span) = (directive.id, directive.span);
3663 let msg = "`self` no longer imports values";
3664 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
3667 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
3668 if self.proc_macro_enabled { return; }
3671 if attr.path.segments.len() > 1 {
3674 let ident = attr.path.segments[0].identifier;
3675 let result = self.resolve_lexical_macro_path_segment(ident,
3679 if let Ok(binding) = result {
3680 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
3681 attr::mark_known(attr);
3683 let msg = "attribute procedural macros are experimental";
3684 let feature = "proc_macro";
3686 feature_err(&self.session.parse_sess, feature,
3687 attr.span, GateIssue::Language, msg)
3688 .span_note(binding.span(), "procedural macro imported here")
3696 fn is_struct_like(def: Def) -> bool {
3698 Def::VariantCtor(_, CtorKind::Fictive) => true,
3699 _ => PathSource::Struct.is_expected(def),
3703 fn is_self_type(path: &[SpannedIdent], namespace: Namespace) -> bool {
3704 namespace == TypeNS && path.len() == 1 && path[0].node.name == keywords::SelfType.name()
3707 fn is_self_value(path: &[SpannedIdent], namespace: Namespace) -> bool {
3708 namespace == ValueNS && path.len() == 1 && path[0].node.name == keywords::SelfValue.name()
3711 fn names_to_string(idents: &[SpannedIdent]) -> String {
3712 let mut result = String::new();
3713 for (i, ident) in idents.iter()
3714 .filter(|i| i.node.name != keywords::CrateRoot.name())
3717 result.push_str("::");
3719 result.push_str(&ident.node.name.as_str());
3724 fn path_names_to_string(path: &Path) -> String {
3725 names_to_string(&path.segments.iter()
3726 .map(|seg| respan(seg.span, seg.identifier))
3727 .collect::<Vec<_>>())
3730 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
3731 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
3732 let variant_path = &suggestion.path;
3733 let variant_path_string = path_names_to_string(variant_path);
3735 let path_len = suggestion.path.segments.len();
3736 let enum_path = ast::Path {
3737 span: suggestion.path.span,
3738 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
3740 let enum_path_string = path_names_to_string(&enum_path);
3742 (suggestion.path.span, variant_path_string, enum_path_string)
3746 /// When an entity with a given name is not available in scope, we search for
3747 /// entities with that name in all crates. This method allows outputting the
3748 /// results of this search in a programmer-friendly way
3749 fn show_candidates(err: &mut DiagnosticBuilder,
3751 candidates: &[ImportSuggestion],
3755 // we want consistent results across executions, but candidates are produced
3756 // by iterating through a hash map, so make sure they are ordered:
3757 let mut path_strings: Vec<_> =
3758 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
3759 path_strings.sort();
3761 let better = if better { "better " } else { "" };
3762 let msg_diff = match path_strings.len() {
3763 1 => " is found in another module, you can import it",
3764 _ => "s are found in other modules, you can import them",
3766 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
3768 for candidate in &mut path_strings {
3769 // produce an additional newline to separate the new use statement
3770 // from the directly following item.
3771 let additional_newline = if found_use {
3776 *candidate = format!("use {};\n{}", candidate, additional_newline);
3779 err.span_suggestions(span, &msg, path_strings);
3782 /// A somewhat inefficient routine to obtain the name of a module.
3783 fn module_to_string(module: Module) -> String {
3784 let mut names = Vec::new();
3786 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
3787 if let ModuleKind::Def(_, name) = module.kind {
3788 if let Some(parent) = module.parent {
3789 names.push(Ident::with_empty_ctxt(name));
3790 collect_mod(names, parent);
3793 // danger, shouldn't be ident?
3794 names.push(Ident::from_str("<opaque>"));
3795 collect_mod(names, module.parent.unwrap());
3798 collect_mod(&mut names, module);
3800 if names.is_empty() {
3801 return "???".to_string();
3803 names_to_string(&names.into_iter()
3805 .map(|n| dummy_spanned(n))
3806 .collect::<Vec<_>>())
3809 fn err_path_resolution() -> PathResolution {
3810 PathResolution::new(Def::Err)
3813 #[derive(PartialEq,Copy, Clone)]
3814 pub enum MakeGlobMap {
3819 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }