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/")]
15 #![feature(rustc_diagnostic_macros)]
16 #![feature(slice_sort_by_cached_key)]
22 extern crate syntax_pos;
23 extern crate rustc_errors as errors;
27 extern crate rustc_data_structures;
29 use self::Namespace::*;
30 use self::TypeParameters::*;
33 use rustc::hir::map::{Definitions, DefCollector};
34 use rustc::hir::{self, PrimTy, TyBool, TyChar, TyFloat, TyInt, TyUint, TyStr};
35 use rustc::middle::cstore::{CrateStore, CrateLoader};
36 use rustc::session::Session;
38 use rustc::hir::def::*;
39 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
41 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
42 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
44 use syntax::codemap::{BytePos, CodeMap};
45 use syntax::ext::hygiene::{Mark, MarkKind, SyntaxContext};
46 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
47 use syntax::ext::base::SyntaxExtension;
48 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
49 use syntax::ext::base::MacroKind;
50 use syntax::symbol::{Symbol, keywords};
51 use syntax::util::lev_distance::find_best_match_for_name;
53 use syntax::visit::{self, FnKind, Visitor};
55 use syntax::ast::{Arm, BindingMode, Block, Crate, Expr, ExprKind};
56 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParam, Generics};
57 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
58 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
59 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
60 use syntax::feature_gate::{feature_err, GateIssue};
61 use syntax::parse::token;
64 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
65 use errors::{DiagnosticBuilder, DiagnosticId};
67 use std::cell::{Cell, RefCell};
69 use std::collections::BTreeSet;
72 use std::mem::replace;
73 use rustc_data_structures::sync::Lrc;
75 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
76 use macros::{InvocationData, LegacyBinding, LegacyScope, MacroBinding};
78 // NB: This module needs to be declared first so diagnostics are
79 // registered before they are used.
84 mod build_reduced_graph;
87 /// A free importable items suggested in case of resolution failure.
88 struct ImportSuggestion {
92 /// A field or associated item from self type suggested in case of resolution failure.
93 enum AssocSuggestion {
100 struct BindingError {
102 origin: BTreeSet<Span>,
103 target: BTreeSet<Span>,
106 impl PartialOrd for BindingError {
107 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
108 Some(self.cmp(other))
112 impl PartialEq for BindingError {
113 fn eq(&self, other: &BindingError) -> bool {
114 self.name == other.name
118 impl Ord for BindingError {
119 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
120 self.name.cmp(&other.name)
124 enum ResolutionError<'a> {
125 /// error E0401: can't use type parameters from outer function
126 TypeParametersFromOuterFunction(Def),
127 /// error E0403: the name is already used for a type parameter in this type parameter list
128 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
129 /// error E0407: method is not a member of trait
130 MethodNotMemberOfTrait(Name, &'a str),
131 /// error E0437: type is not a member of trait
132 TypeNotMemberOfTrait(Name, &'a str),
133 /// error E0438: const is not a member of trait
134 ConstNotMemberOfTrait(Name, &'a str),
135 /// error E0408: variable `{}` is not bound in all patterns
136 VariableNotBoundInPattern(&'a BindingError),
137 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
138 VariableBoundWithDifferentMode(Name, Span),
139 /// error E0415: identifier is bound more than once in this parameter list
140 IdentifierBoundMoreThanOnceInParameterList(&'a str),
141 /// error E0416: identifier is bound more than once in the same pattern
142 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
143 /// error E0426: use of undeclared label
144 UndeclaredLabel(&'a str, Option<Name>),
145 /// error E0429: `self` imports are only allowed within a { } list
146 SelfImportsOnlyAllowedWithin,
147 /// error E0430: `self` import can only appear once in the list
148 SelfImportCanOnlyAppearOnceInTheList,
149 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
150 SelfImportOnlyInImportListWithNonEmptyPrefix,
151 /// error E0432: unresolved import
152 UnresolvedImport(Option<(Span, &'a str, &'a str)>),
153 /// error E0433: failed to resolve
154 FailedToResolve(&'a str),
155 /// error E0434: can't capture dynamic environment in a fn item
156 CannotCaptureDynamicEnvironmentInFnItem,
157 /// error E0435: attempt to use a non-constant value in a constant
158 AttemptToUseNonConstantValueInConstant,
159 /// error E0530: X bindings cannot shadow Ys
160 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
161 /// error E0128: type parameters with a default cannot use forward declared identifiers
162 ForwardDeclaredTyParam,
165 /// Combines an error with provided span and emits it
167 /// This takes the error provided, combines it with the span and any additional spans inside the
168 /// error and emits it.
169 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
171 resolution_error: ResolutionError<'a>) {
172 resolve_struct_error(resolver, span, resolution_error).emit();
175 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
177 resolution_error: ResolutionError<'a>)
178 -> DiagnosticBuilder<'sess> {
179 match resolution_error {
180 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
181 let mut err = struct_span_err!(resolver.session,
184 "can't use type parameters from outer function");
185 err.span_label(span, "use of type variable from outer function");
187 let cm = resolver.session.codemap();
189 Def::SelfTy(_, maybe_impl_defid) => {
190 if let Some(impl_span) = maybe_impl_defid.map_or(None,
191 |def_id| resolver.definitions.opt_span(def_id)) {
192 err.span_label(reduce_impl_span_to_impl_keyword(cm, impl_span),
193 "`Self` type implicitely declared here, on the `impl`");
196 Def::TyParam(typaram_defid) => {
197 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
198 err.span_label(typaram_span, "type variable from outer function");
201 Def::Mod(..) | Def::Struct(..) | Def::Union(..) | Def::Enum(..) | Def::Variant(..) |
202 Def::Trait(..) | Def::TyAlias(..) | Def::TyForeign(..) | Def::TraitAlias(..) |
203 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::Fn(..) | Def::Const(..) |
204 Def::Static(..) | Def::StructCtor(..) | Def::VariantCtor(..) | Def::Method(..) |
205 Def::AssociatedConst(..) | Def::Local(..) | Def::Upvar(..) | Def::Label(..) |
206 Def::Macro(..) | Def::GlobalAsm(..) | Def::Err =>
207 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
211 // Try to retrieve the span of the function signature and generate a new message with
212 // a local type parameter
213 let sugg_msg = "try using a local type parameter instead";
214 if let Some((sugg_span, new_snippet)) = generate_local_type_param_snippet(cm, span) {
215 // Suggest the modification to the user
216 err.span_suggestion(sugg_span,
219 } else if let Some(sp) = generate_fn_name_span(cm, span) {
220 err.span_label(sp, "try adding a local type parameter in this method instead");
222 err.help("try using a local type parameter instead");
227 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
228 let mut err = struct_span_err!(resolver.session,
231 "the name `{}` is already used for a type parameter \
232 in this type parameter list",
234 err.span_label(span, "already used");
235 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
238 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
239 let mut err = struct_span_err!(resolver.session,
242 "method `{}` is not a member of trait `{}`",
245 err.span_label(span, format!("not a member of trait `{}`", trait_));
248 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
249 let mut err = struct_span_err!(resolver.session,
252 "type `{}` is not a member of trait `{}`",
255 err.span_label(span, format!("not a member of trait `{}`", trait_));
258 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
259 let mut err = struct_span_err!(resolver.session,
262 "const `{}` is not a member of trait `{}`",
265 err.span_label(span, format!("not a member of trait `{}`", trait_));
268 ResolutionError::VariableNotBoundInPattern(binding_error) => {
269 let target_sp = binding_error.target.iter().map(|x| *x).collect::<Vec<_>>();
270 let msp = MultiSpan::from_spans(target_sp.clone());
271 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
272 let mut err = resolver.session.struct_span_err_with_code(
275 DiagnosticId::Error("E0408".into()),
277 for sp in target_sp {
278 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
280 let origin_sp = binding_error.origin.iter().map(|x| *x).collect::<Vec<_>>();
281 for sp in origin_sp {
282 err.span_label(sp, "variable not in all patterns");
286 ResolutionError::VariableBoundWithDifferentMode(variable_name,
287 first_binding_span) => {
288 let mut err = struct_span_err!(resolver.session,
291 "variable `{}` is bound in inconsistent \
292 ways within the same match arm",
294 err.span_label(span, "bound in different ways");
295 err.span_label(first_binding_span, "first binding");
298 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
299 let mut err = struct_span_err!(resolver.session,
302 "identifier `{}` is bound more than once in this parameter list",
304 err.span_label(span, "used as parameter more than once");
307 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
308 let mut err = struct_span_err!(resolver.session,
311 "identifier `{}` is bound more than once in the same pattern",
313 err.span_label(span, "used in a pattern more than once");
316 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
317 let mut err = struct_span_err!(resolver.session,
320 "use of undeclared label `{}`",
322 if let Some(lev_candidate) = lev_candidate {
323 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
325 err.span_label(span, format!("undeclared label `{}`", name));
329 ResolutionError::SelfImportsOnlyAllowedWithin => {
330 struct_span_err!(resolver.session,
334 "`self` imports are only allowed within a { } list")
336 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
337 let mut err = struct_span_err!(resolver.session, span, E0430,
338 "`self` import can only appear once in an import list");
339 err.span_label(span, "can only appear once in an import list");
342 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
343 let mut err = struct_span_err!(resolver.session, span, E0431,
344 "`self` import can only appear in an import list with \
345 a non-empty prefix");
346 err.span_label(span, "can only appear in an import list with a non-empty prefix");
349 ResolutionError::UnresolvedImport(name) => {
350 let (span, msg) = match name {
351 Some((sp, n, _)) => (sp, format!("unresolved import `{}`", n)),
352 None => (span, "unresolved import".to_owned()),
354 let mut err = struct_span_err!(resolver.session, span, E0432, "{}", msg);
355 if let Some((_, _, p)) = name {
356 err.span_label(span, p);
360 ResolutionError::FailedToResolve(msg) => {
361 let mut err = struct_span_err!(resolver.session, span, E0433,
362 "failed to resolve. {}", msg);
363 err.span_label(span, msg);
366 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
367 let mut err = struct_span_err!(resolver.session,
371 "can't capture dynamic environment in a fn item");
372 err.help("use the `|| { ... }` closure form instead");
375 ResolutionError::AttemptToUseNonConstantValueInConstant => {
376 let mut err = struct_span_err!(resolver.session, span, E0435,
377 "attempt to use a non-constant value in a constant");
378 err.span_label(span, "non-constant value");
381 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
382 let shadows_what = PathResolution::new(binding.def()).kind_name();
383 let mut err = struct_span_err!(resolver.session,
386 "{}s cannot shadow {}s", what_binding, shadows_what);
387 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
388 let participle = if binding.is_import() { "imported" } else { "defined" };
389 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
390 err.span_label(binding.span, msg);
393 ResolutionError::ForwardDeclaredTyParam => {
394 let mut err = struct_span_err!(resolver.session, span, E0128,
395 "type parameters with a default cannot use \
396 forward declared identifiers");
397 err.span_label(span, format!("defaulted type parameters cannot be forward declared"));
403 /// Adjust the impl span so that just the `impl` keyword is taken by removing
404 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
405 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
407 /// Attention: The method used is very fragile since it essentially duplicates the work of the
408 /// parser. If you need to use this function or something similar, please consider updating the
409 /// codemap functions and this function to something more robust.
410 fn reduce_impl_span_to_impl_keyword(cm: &CodeMap, impl_span: Span) -> Span {
411 let impl_span = cm.span_until_char(impl_span, '<');
412 let impl_span = cm.span_until_whitespace(impl_span);
416 fn generate_fn_name_span(cm: &CodeMap, span: Span) -> Option<Span> {
417 let prev_span = cm.span_extend_to_prev_str(span, "fn", true);
418 cm.span_to_snippet(prev_span).map(|snippet| {
419 let len = snippet.find(|c: char| !c.is_alphanumeric() && c != '_')
420 .expect("no label after fn");
421 prev_span.with_hi(BytePos(prev_span.lo().0 + len as u32))
425 /// Take the span of a type parameter in a function signature and try to generate a span for the
426 /// function name (with generics) and a new snippet for this span with the pointed type parameter as
427 /// a new local type parameter.
430 /// ```rust,ignore (pseudo-Rust)
432 /// fn my_function(param: T)
433 /// // ^ Original span
436 /// fn my_function(param: T)
437 /// // ^^^^^^^^^^^ Generated span with snippet `my_function<T>`
440 /// Attention: The method used is very fragile since it essentially duplicates the work of the
441 /// parser. If you need to use this function or something similar, please consider updating the
442 /// codemap functions and this function to something more robust.
443 fn generate_local_type_param_snippet(cm: &CodeMap, span: Span) -> Option<(Span, String)> {
444 // Try to extend the span to the previous "fn" keyword to retrieve the function
446 let sugg_span = cm.span_extend_to_prev_str(span, "fn", false);
447 if sugg_span != span {
448 if let Ok(snippet) = cm.span_to_snippet(sugg_span) {
449 // Consume the function name
450 let mut offset = snippet.find(|c: char| !c.is_alphanumeric() && c != '_')
451 .expect("no label after fn");
453 // Consume the generics part of the function signature
454 let mut bracket_counter = 0;
455 let mut last_char = None;
456 for c in snippet[offset..].chars() {
458 '<' => bracket_counter += 1,
459 '>' => bracket_counter -= 1,
460 '(' => if bracket_counter == 0 { break; }
463 offset += c.len_utf8();
467 // Adjust the suggestion span to encompass the function name with its generics
468 let sugg_span = sugg_span.with_hi(BytePos(sugg_span.lo().0 + offset as u32));
470 // Prepare the new suggested snippet to append the type parameter that triggered
471 // the error in the generics of the function signature
472 let mut new_snippet = if last_char == Some('>') {
473 format!("{}, ", &snippet[..(offset - '>'.len_utf8())])
475 format!("{}<", &snippet[..offset])
477 new_snippet.push_str(&cm.span_to_snippet(span).unwrap_or("T".to_string()));
478 new_snippet.push('>');
480 return Some((sugg_span, new_snippet));
487 #[derive(Copy, Clone, Debug)]
490 binding_mode: BindingMode,
493 /// Map from the name in a pattern to its binding mode.
494 type BindingMap = FxHashMap<Ident, BindingInfo>;
496 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
507 fn descr(self) -> &'static str {
509 PatternSource::Match => "match binding",
510 PatternSource::IfLet => "if let binding",
511 PatternSource::WhileLet => "while let binding",
512 PatternSource::Let => "let binding",
513 PatternSource::For => "for binding",
514 PatternSource::FnParam => "function parameter",
519 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
520 enum AliasPossibility {
525 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
526 enum PathSource<'a> {
527 // Type paths `Path`.
529 // Trait paths in bounds or impls.
530 Trait(AliasPossibility),
531 // Expression paths `path`, with optional parent context.
532 Expr(Option<&'a Expr>),
533 // Paths in path patterns `Path`.
535 // Paths in struct expressions and patterns `Path { .. }`.
537 // Paths in tuple struct patterns `Path(..)`.
539 // `m::A::B` in `<T as m::A>::B::C`.
540 TraitItem(Namespace),
541 // Path in `pub(path)`
543 // Path in `use a::b::{...};`
547 impl<'a> PathSource<'a> {
548 fn namespace(self) -> Namespace {
550 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
551 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
552 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
553 PathSource::TraitItem(ns) => ns,
557 fn global_by_default(self) -> bool {
559 PathSource::Visibility | PathSource::ImportPrefix => true,
560 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
561 PathSource::Struct | PathSource::TupleStruct |
562 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
566 fn defer_to_typeck(self) -> bool {
568 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
569 PathSource::Struct | PathSource::TupleStruct => true,
570 PathSource::Trait(_) | PathSource::TraitItem(..) |
571 PathSource::Visibility | PathSource::ImportPrefix => false,
575 fn descr_expected(self) -> &'static str {
577 PathSource::Type => "type",
578 PathSource::Trait(_) => "trait",
579 PathSource::Pat => "unit struct/variant or constant",
580 PathSource::Struct => "struct, variant or union type",
581 PathSource::TupleStruct => "tuple struct/variant",
582 PathSource::Visibility => "module",
583 PathSource::ImportPrefix => "module or enum",
584 PathSource::TraitItem(ns) => match ns {
585 TypeNS => "associated type",
586 ValueNS => "method or associated constant",
587 MacroNS => bug!("associated macro"),
589 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
590 // "function" here means "anything callable" rather than `Def::Fn`,
591 // this is not precise but usually more helpful than just "value".
592 Some(&ExprKind::Call(..)) => "function",
598 fn is_expected(self, def: Def) -> bool {
600 PathSource::Type => match def {
601 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
602 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
603 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
604 Def::TyForeign(..) => true,
607 PathSource::Trait(AliasPossibility::No) => match def {
608 Def::Trait(..) => true,
611 PathSource::Trait(AliasPossibility::Maybe) => match def {
612 Def::Trait(..) => true,
613 Def::TraitAlias(..) => true,
616 PathSource::Expr(..) => match def {
617 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
618 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
619 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
620 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) => true,
623 PathSource::Pat => match def {
624 Def::StructCtor(_, CtorKind::Const) |
625 Def::VariantCtor(_, CtorKind::Const) |
626 Def::Const(..) | Def::AssociatedConst(..) => true,
629 PathSource::TupleStruct => match def {
630 Def::StructCtor(_, CtorKind::Fn) | Def::VariantCtor(_, CtorKind::Fn) => true,
633 PathSource::Struct => match def {
634 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
635 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
638 PathSource::TraitItem(ns) => match def {
639 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
640 Def::AssociatedTy(..) if ns == TypeNS => true,
643 PathSource::ImportPrefix => match def {
644 Def::Mod(..) | Def::Enum(..) => true,
647 PathSource::Visibility => match def {
648 Def::Mod(..) => true,
654 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
655 __diagnostic_used!(E0404);
656 __diagnostic_used!(E0405);
657 __diagnostic_used!(E0412);
658 __diagnostic_used!(E0422);
659 __diagnostic_used!(E0423);
660 __diagnostic_used!(E0425);
661 __diagnostic_used!(E0531);
662 __diagnostic_used!(E0532);
663 __diagnostic_used!(E0573);
664 __diagnostic_used!(E0574);
665 __diagnostic_used!(E0575);
666 __diagnostic_used!(E0576);
667 __diagnostic_used!(E0577);
668 __diagnostic_used!(E0578);
669 match (self, has_unexpected_resolution) {
670 (PathSource::Trait(_), true) => "E0404",
671 (PathSource::Trait(_), false) => "E0405",
672 (PathSource::Type, true) => "E0573",
673 (PathSource::Type, false) => "E0412",
674 (PathSource::Struct, true) => "E0574",
675 (PathSource::Struct, false) => "E0422",
676 (PathSource::Expr(..), true) => "E0423",
677 (PathSource::Expr(..), false) => "E0425",
678 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
679 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
680 (PathSource::TraitItem(..), true) => "E0575",
681 (PathSource::TraitItem(..), false) => "E0576",
682 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
683 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
688 /// Different kinds of symbols don't influence each other.
690 /// Therefore, they have a separate universe (namespace).
691 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
698 /// Just a helper ‒ separate structure for each namespace.
699 #[derive(Clone, Default, Debug)]
700 pub struct PerNS<T> {
706 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
708 fn index(&self, ns: Namespace) -> &T {
710 ValueNS => &self.value_ns,
711 TypeNS => &self.type_ns,
712 MacroNS => &self.macro_ns,
717 impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
718 fn index_mut(&mut self, ns: Namespace) -> &mut T {
720 ValueNS => &mut self.value_ns,
721 TypeNS => &mut self.type_ns,
722 MacroNS => &mut self.macro_ns,
727 struct UsePlacementFinder {
728 target_module: NodeId,
733 impl UsePlacementFinder {
734 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
735 let mut finder = UsePlacementFinder {
740 visit::walk_crate(&mut finder, krate);
741 (finder.span, finder.found_use)
745 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
748 module: &'tcx ast::Mod,
750 _: &[ast::Attribute],
753 if self.span.is_some() {
756 if node_id != self.target_module {
757 visit::walk_mod(self, module);
760 // find a use statement
761 for item in &module.items {
763 ItemKind::Use(..) => {
764 // don't suggest placing a use before the prelude
765 // import or other generated ones
766 if item.span.ctxt().outer().expn_info().is_none() {
767 self.span = Some(item.span.shrink_to_lo());
768 self.found_use = true;
772 // don't place use before extern crate
773 ItemKind::ExternCrate(_) => {}
774 // but place them before the first other item
775 _ => if self.span.map_or(true, |span| item.span < span ) {
776 if item.span.ctxt().outer().expn_info().is_none() {
777 // don't insert between attributes and an item
778 if item.attrs.is_empty() {
779 self.span = Some(item.span.shrink_to_lo());
781 // find the first attribute on the item
782 for attr in &item.attrs {
783 if self.span.map_or(true, |span| attr.span < span) {
784 self.span = Some(attr.span.shrink_to_lo());
795 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
796 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
797 fn visit_item(&mut self, item: &'tcx Item) {
798 self.resolve_item(item);
800 fn visit_arm(&mut self, arm: &'tcx Arm) {
801 self.resolve_arm(arm);
803 fn visit_block(&mut self, block: &'tcx Block) {
804 self.resolve_block(block);
806 fn visit_expr(&mut self, expr: &'tcx Expr) {
807 self.resolve_expr(expr, None);
809 fn visit_local(&mut self, local: &'tcx Local) {
810 self.resolve_local(local);
812 fn visit_ty(&mut self, ty: &'tcx Ty) {
814 TyKind::Path(ref qself, ref path) => {
815 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
817 TyKind::ImplicitSelf => {
818 let self_ty = keywords::SelfType.ident();
819 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, true, ty.span)
820 .map_or(Def::Err, |d| d.def());
821 self.record_def(ty.id, PathResolution::new(def));
823 TyKind::Array(ref element, ref length) => {
824 self.visit_ty(element);
825 self.with_constant_rib(|this| {
826 this.visit_expr(length);
832 visit::walk_ty(self, ty);
834 fn visit_poly_trait_ref(&mut self,
835 tref: &'tcx ast::PolyTraitRef,
836 m: &'tcx ast::TraitBoundModifier) {
837 self.smart_resolve_path(tref.trait_ref.ref_id, None,
838 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
839 visit::walk_poly_trait_ref(self, tref, m);
841 fn visit_variant(&mut self,
842 variant: &'tcx ast::Variant,
843 generics: &'tcx Generics,
844 item_id: ast::NodeId) {
845 if let Some(ref dis_expr) = variant.node.disr_expr {
846 // resolve the discriminator expr as a constant
847 self.with_constant_rib(|this| {
848 this.visit_expr(dis_expr);
852 // `visit::walk_variant` without the discriminant expression.
853 self.visit_variant_data(&variant.node.data,
859 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
860 let type_parameters = match foreign_item.node {
861 ForeignItemKind::Fn(_, ref generics) => {
862 HasTypeParameters(generics, ItemRibKind)
864 ForeignItemKind::Static(..) => NoTypeParameters,
865 ForeignItemKind::Ty => NoTypeParameters,
866 ForeignItemKind::Macro(..) => NoTypeParameters,
868 self.with_type_parameter_rib(type_parameters, |this| {
869 visit::walk_foreign_item(this, foreign_item);
872 fn visit_fn(&mut self,
873 function_kind: FnKind<'tcx>,
874 declaration: &'tcx FnDecl,
877 let rib_kind = match function_kind {
878 FnKind::ItemFn(..) => {
881 FnKind::Method(_, _, _, _) => {
882 TraitOrImplItemRibKind
884 FnKind::Closure(_) => ClosureRibKind(node_id),
887 // Create a value rib for the function.
888 self.ribs[ValueNS].push(Rib::new(rib_kind));
890 // Create a label rib for the function.
891 self.label_ribs.push(Rib::new(rib_kind));
893 // Add each argument to the rib.
894 let mut bindings_list = FxHashMap();
895 for argument in &declaration.inputs {
896 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
898 self.visit_ty(&argument.ty);
900 debug!("(resolving function) recorded argument");
902 visit::walk_fn_ret_ty(self, &declaration.output);
904 // Resolve the function body.
905 match function_kind {
906 FnKind::ItemFn(.., body) |
907 FnKind::Method(.., body) => {
908 self.visit_block(body);
910 FnKind::Closure(body) => {
911 self.visit_expr(body);
915 debug!("(resolving function) leaving function");
917 self.label_ribs.pop();
918 self.ribs[ValueNS].pop();
920 fn visit_generics(&mut self, generics: &'tcx Generics) {
921 // For type parameter defaults, we have to ban access
922 // to following type parameters, as the Substs can only
923 // provide previous type parameters as they're built. We
924 // put all the parameters on the ban list and then remove
925 // them one by one as they are processed and become available.
926 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
927 default_ban_rib.bindings.extend(generics.params.iter()
928 .filter_map(|p| if let GenericParam::Type(ref tp) = *p { Some(tp) } else { None })
929 .skip_while(|p| p.default.is_none())
930 .map(|p| (Ident::with_empty_ctxt(p.ident.name), Def::Err)));
932 for param in &generics.params {
934 GenericParam::Lifetime(_) => self.visit_generic_param(param),
935 GenericParam::Type(ref ty_param) => {
936 for bound in &ty_param.bounds {
937 self.visit_ty_param_bound(bound);
940 if let Some(ref ty) = ty_param.default {
941 self.ribs[TypeNS].push(default_ban_rib);
943 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
946 // Allow all following defaults to refer to this type parameter.
947 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(ty_param.ident.name));
951 for p in &generics.where_clause.predicates { self.visit_where_predicate(p); }
955 #[derive(Copy, Clone)]
956 enum TypeParameters<'a, 'b> {
958 HasTypeParameters(// Type parameters.
961 // The kind of the rib used for type parameters.
965 /// The rib kind controls the translation of local
966 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
967 #[derive(Copy, Clone, Debug)]
969 /// No translation needs to be applied.
972 /// We passed through a closure scope at the given node ID.
973 /// Translate upvars as appropriate.
974 ClosureRibKind(NodeId /* func id */),
976 /// We passed through an impl or trait and are now in one of its
977 /// methods or associated types. Allow references to ty params that impl or trait
978 /// binds. Disallow any other upvars (including other ty params that are
980 TraitOrImplItemRibKind,
982 /// We passed through an item scope. Disallow upvars.
985 /// We're in a constant item. Can't refer to dynamic stuff.
988 /// We passed through a module.
989 ModuleRibKind(Module<'a>),
991 /// We passed through a `macro_rules!` statement
992 MacroDefinition(DefId),
994 /// All bindings in this rib are type parameters that can't be used
995 /// from the default of a type parameter because they're not declared
996 /// before said type parameter. Also see the `visit_generics` override.
997 ForwardTyParamBanRibKind,
1000 /// One local scope.
1002 /// A rib represents a scope names can live in. Note that these appear in many places, not just
1003 /// around braces. At any place where the list of accessible names (of the given namespace)
1004 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
1005 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
1008 /// Different [rib kinds](enum.RibKind) are transparent for different names.
1010 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
1011 /// resolving, the name is looked up from inside out.
1014 bindings: FxHashMap<Ident, Def>,
1019 fn new(kind: RibKind<'a>) -> Rib<'a> {
1021 bindings: FxHashMap(),
1027 /// An intermediate resolution result.
1029 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
1030 /// items are visible in their whole block, while defs only from the place they are defined
1032 enum LexicalScopeBinding<'a> {
1033 Item(&'a NameBinding<'a>),
1037 impl<'a> LexicalScopeBinding<'a> {
1038 fn item(self) -> Option<&'a NameBinding<'a>> {
1040 LexicalScopeBinding::Item(binding) => Some(binding),
1045 fn def(self) -> Def {
1047 LexicalScopeBinding::Item(binding) => binding.def(),
1048 LexicalScopeBinding::Def(def) => def,
1053 #[derive(Clone, Debug)]
1054 enum PathResult<'a> {
1056 NonModule(PathResolution),
1058 Failed(Span, String, bool /* is the error from the last segment? */),
1062 /// An anonymous module, eg. just a block.
1066 /// fn f() {} // (1)
1067 /// { // This is an anonymous module
1068 /// f(); // This resolves to (2) as we are inside the block.
1069 /// fn f() {} // (2)
1071 /// f(); // Resolves to (1)
1075 /// Any module with a name.
1079 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1080 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1085 /// One node in the tree of modules.
1086 pub struct ModuleData<'a> {
1087 parent: Option<Module<'a>>,
1090 // The def id of the closest normal module (`mod`) ancestor (including this module).
1091 normal_ancestor_id: DefId,
1093 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1094 legacy_macro_resolutions: RefCell<Vec<(Mark, Ident, Span, MacroKind)>>,
1095 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1097 // Macro invocations that can expand into items in this module.
1098 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1100 no_implicit_prelude: bool,
1102 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1103 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1105 // Used to memoize the traits in this module for faster searches through all traits in scope.
1106 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1108 // Whether this module is populated. If not populated, any attempt to
1109 // access the children must be preceded with a
1110 // `populate_module_if_necessary` call.
1111 populated: Cell<bool>,
1113 /// Span of the module itself. Used for error reporting.
1119 type Module<'a> = &'a ModuleData<'a>;
1121 impl<'a> ModuleData<'a> {
1122 fn new(parent: Option<Module<'a>>,
1124 normal_ancestor_id: DefId,
1126 span: Span) -> Self {
1131 resolutions: RefCell::new(FxHashMap()),
1132 legacy_macro_resolutions: RefCell::new(Vec::new()),
1133 macro_resolutions: RefCell::new(Vec::new()),
1134 unresolved_invocations: RefCell::new(FxHashSet()),
1135 no_implicit_prelude: false,
1136 glob_importers: RefCell::new(Vec::new()),
1137 globs: RefCell::new(Vec::new()),
1138 traits: RefCell::new(None),
1139 populated: Cell::new(normal_ancestor_id.is_local()),
1145 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1146 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1147 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1151 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1152 let resolutions = self.resolutions.borrow();
1153 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1154 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.name.as_str(), ns));
1155 for &(&(ident, ns), &resolution) in resolutions.iter() {
1156 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1160 fn def(&self) -> Option<Def> {
1162 ModuleKind::Def(def, _) => Some(def),
1167 fn def_id(&self) -> Option<DefId> {
1168 self.def().as_ref().map(Def::def_id)
1171 // `self` resolves to the first module ancestor that `is_normal`.
1172 fn is_normal(&self) -> bool {
1174 ModuleKind::Def(Def::Mod(_), _) => true,
1179 fn is_trait(&self) -> bool {
1181 ModuleKind::Def(Def::Trait(_), _) => true,
1186 fn is_local(&self) -> bool {
1187 self.normal_ancestor_id.is_local()
1190 fn nearest_item_scope(&'a self) -> Module<'a> {
1191 if self.is_trait() { self.parent.unwrap() } else { self }
1195 impl<'a> fmt::Debug for ModuleData<'a> {
1196 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1197 write!(f, "{:?}", self.def())
1201 /// Records a possibly-private value, type, or module definition.
1202 #[derive(Clone, Debug)]
1203 pub struct NameBinding<'a> {
1204 kind: NameBindingKind<'a>,
1207 vis: ty::Visibility,
1210 pub trait ToNameBinding<'a> {
1211 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1214 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1215 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1220 #[derive(Clone, Debug)]
1221 enum NameBindingKind<'a> {
1225 binding: &'a NameBinding<'a>,
1226 directive: &'a ImportDirective<'a>,
1228 legacy_self_import: bool,
1231 b1: &'a NameBinding<'a>,
1232 b2: &'a NameBinding<'a>,
1237 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1239 struct UseError<'a> {
1240 err: DiagnosticBuilder<'a>,
1241 /// Attach `use` statements for these candidates
1242 candidates: Vec<ImportSuggestion>,
1243 /// The node id of the module to place the use statements in
1245 /// Whether the diagnostic should state that it's "better"
1249 struct AmbiguityError<'a> {
1253 b1: &'a NameBinding<'a>,
1254 b2: &'a NameBinding<'a>,
1258 impl<'a> NameBinding<'a> {
1259 fn module(&self) -> Option<Module<'a>> {
1261 NameBindingKind::Module(module) => Some(module),
1262 NameBindingKind::Import { binding, .. } => binding.module(),
1263 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.module(),
1268 fn def(&self) -> Def {
1270 NameBindingKind::Def(def) => def,
1271 NameBindingKind::Module(module) => module.def().unwrap(),
1272 NameBindingKind::Import { binding, .. } => binding.def(),
1273 NameBindingKind::Ambiguity { legacy: true, b1, .. } => b1.def(),
1274 NameBindingKind::Ambiguity { .. } => Def::Err,
1278 fn def_ignoring_ambiguity(&self) -> Def {
1280 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1281 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1286 fn get_macro(&self, resolver: &mut Resolver<'a>) -> Lrc<SyntaxExtension> {
1287 resolver.get_macro(self.def_ignoring_ambiguity())
1290 // We sometimes need to treat variants as `pub` for backwards compatibility
1291 fn pseudo_vis(&self) -> ty::Visibility {
1292 if self.is_variant() && self.def().def_id().is_local() {
1293 ty::Visibility::Public
1299 fn is_variant(&self) -> bool {
1301 NameBindingKind::Def(Def::Variant(..)) |
1302 NameBindingKind::Def(Def::VariantCtor(..)) => true,
1307 fn is_extern_crate(&self) -> bool {
1309 NameBindingKind::Import {
1310 directive: &ImportDirective {
1311 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1318 fn is_import(&self) -> bool {
1320 NameBindingKind::Import { .. } => true,
1325 fn is_renamed_extern_crate(&self) -> bool {
1326 if let NameBindingKind::Import { directive, ..} = self.kind {
1327 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1334 fn is_glob_import(&self) -> bool {
1336 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1337 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1342 fn is_importable(&self) -> bool {
1344 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1349 fn is_macro_def(&self) -> bool {
1351 NameBindingKind::Def(Def::Macro(..)) => true,
1356 fn descr(&self) -> &'static str {
1357 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1361 /// Interns the names of the primitive types.
1363 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1364 /// special handling, since they have no place of origin.
1365 struct PrimitiveTypeTable {
1366 primitive_types: FxHashMap<Name, PrimTy>,
1369 impl PrimitiveTypeTable {
1370 fn new() -> PrimitiveTypeTable {
1371 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1373 table.intern("bool", TyBool);
1374 table.intern("char", TyChar);
1375 table.intern("f32", TyFloat(FloatTy::F32));
1376 table.intern("f64", TyFloat(FloatTy::F64));
1377 table.intern("isize", TyInt(IntTy::Isize));
1378 table.intern("i8", TyInt(IntTy::I8));
1379 table.intern("i16", TyInt(IntTy::I16));
1380 table.intern("i32", TyInt(IntTy::I32));
1381 table.intern("i64", TyInt(IntTy::I64));
1382 table.intern("i128", TyInt(IntTy::I128));
1383 table.intern("str", TyStr);
1384 table.intern("usize", TyUint(UintTy::Usize));
1385 table.intern("u8", TyUint(UintTy::U8));
1386 table.intern("u16", TyUint(UintTy::U16));
1387 table.intern("u32", TyUint(UintTy::U32));
1388 table.intern("u64", TyUint(UintTy::U64));
1389 table.intern("u128", TyUint(UintTy::U128));
1393 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1394 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1398 /// The main resolver class.
1400 /// This is the visitor that walks the whole crate.
1401 pub struct Resolver<'a> {
1402 session: &'a Session,
1403 cstore: &'a CrateStore,
1405 pub definitions: Definitions,
1407 graph_root: Module<'a>,
1409 prelude: Option<Module<'a>>,
1410 extern_prelude: FxHashSet<Name>,
1412 /// n.b. This is used only for better diagnostics, not name resolution itself.
1413 has_self: FxHashSet<DefId>,
1415 /// Names of fields of an item `DefId` accessible with dot syntax.
1416 /// Used for hints during error reporting.
1417 field_names: FxHashMap<DefId, Vec<Name>>,
1419 /// All imports known to succeed or fail.
1420 determined_imports: Vec<&'a ImportDirective<'a>>,
1422 /// All non-determined imports.
1423 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1425 /// The module that represents the current item scope.
1426 current_module: Module<'a>,
1428 /// The current set of local scopes for types and values.
1429 /// FIXME #4948: Reuse ribs to avoid allocation.
1430 ribs: PerNS<Vec<Rib<'a>>>,
1432 /// The current set of local scopes, for labels.
1433 label_ribs: Vec<Rib<'a>>,
1435 /// The trait that the current context can refer to.
1436 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1438 /// The current self type if inside an impl (used for better errors).
1439 current_self_type: Option<Ty>,
1441 /// The idents for the primitive types.
1442 primitive_type_table: PrimitiveTypeTable,
1445 pub freevars: FreevarMap,
1446 freevars_seen: NodeMap<NodeMap<usize>>,
1447 pub export_map: ExportMap,
1448 pub trait_map: TraitMap,
1450 /// A map from nodes to anonymous modules.
1451 /// Anonymous modules are pseudo-modules that are implicitly created around items
1452 /// contained within blocks.
1454 /// For example, if we have this:
1462 /// There will be an anonymous module created around `g` with the ID of the
1463 /// entry block for `f`.
1464 block_map: NodeMap<Module<'a>>,
1465 module_map: FxHashMap<DefId, Module<'a>>,
1466 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1468 pub make_glob_map: bool,
1469 /// Maps imports to the names of items actually imported (this actually maps
1470 /// all imports, but only glob imports are actually interesting).
1471 pub glob_map: GlobMap,
1473 used_imports: FxHashSet<(NodeId, Namespace)>,
1474 pub maybe_unused_trait_imports: NodeSet,
1475 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1477 /// privacy errors are delayed until the end in order to deduplicate them
1478 privacy_errors: Vec<PrivacyError<'a>>,
1479 /// ambiguity errors are delayed for deduplication
1480 ambiguity_errors: Vec<AmbiguityError<'a>>,
1481 /// `use` injections are delayed for better placement and deduplication
1482 use_injections: Vec<UseError<'a>>,
1483 /// `use` injections for proc macros wrongly imported with #[macro_use]
1484 proc_mac_errors: Vec<macros::ProcMacError>,
1486 gated_errors: FxHashSet<Span>,
1487 disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
1489 arenas: &'a ResolverArenas<'a>,
1490 dummy_binding: &'a NameBinding<'a>,
1491 /// true if `#![feature(use_extern_macros)]`
1492 use_extern_macros: bool,
1494 crate_loader: &'a mut CrateLoader,
1495 macro_names: FxHashSet<Ident>,
1496 global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1497 pub all_macros: FxHashMap<Name, Def>,
1498 lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
1499 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1500 macro_defs: FxHashMap<Mark, DefId>,
1501 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1502 macro_exports: Vec<Export>,
1503 pub whitelisted_legacy_custom_derives: Vec<Name>,
1504 pub found_unresolved_macro: bool,
1506 /// List of crate local macros that we need to warn about as being unused.
1507 /// Right now this only includes macro_rules! macros, and macros 2.0.
1508 unused_macros: FxHashSet<DefId>,
1510 /// Maps the `Mark` of an expansion to its containing module or block.
1511 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1513 /// Avoid duplicated errors for "name already defined".
1514 name_already_seen: FxHashMap<Name, Span>,
1516 /// If `#![feature(proc_macro)]` is set
1517 proc_macro_enabled: bool,
1519 /// A set of procedural macros imported by `#[macro_use]` that have already been warned about
1520 warned_proc_macros: FxHashSet<Name>,
1522 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1524 /// This table maps struct IDs into struct constructor IDs,
1525 /// it's not used during normal resolution, only for better error reporting.
1526 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1528 /// Only used for better errors on `fn(): fn()`
1529 current_type_ascription: Vec<Span>,
1531 injected_crate: Option<Module<'a>>,
1534 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1535 pub struct ResolverArenas<'a> {
1536 modules: arena::TypedArena<ModuleData<'a>>,
1537 local_modules: RefCell<Vec<Module<'a>>>,
1538 name_bindings: arena::TypedArena<NameBinding<'a>>,
1539 import_directives: arena::TypedArena<ImportDirective<'a>>,
1540 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1541 invocation_data: arena::TypedArena<InvocationData<'a>>,
1542 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1545 impl<'a> ResolverArenas<'a> {
1546 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1547 let module = self.modules.alloc(module);
1548 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1549 self.local_modules.borrow_mut().push(module);
1553 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1554 self.local_modules.borrow()
1556 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1557 self.name_bindings.alloc(name_binding)
1559 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1560 -> &'a ImportDirective {
1561 self.import_directives.alloc(import_directive)
1563 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1564 self.name_resolutions.alloc(Default::default())
1566 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1567 -> &'a InvocationData<'a> {
1568 self.invocation_data.alloc(expansion_data)
1570 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1571 self.legacy_bindings.alloc(binding)
1575 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1576 fn parent(self, id: DefId) -> Option<DefId> {
1578 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1579 _ => self.cstore.def_key(id).parent,
1580 }.map(|index| DefId { index, ..id })
1584 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1585 /// the resolver is no longer needed as all the relevant information is inline.
1586 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1587 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1588 self.resolve_hir_path_cb(path, is_value,
1589 |resolver, span, error| resolve_error(resolver, span, error))
1592 fn resolve_str_path(&mut self, span: Span, crate_root: Option<&str>,
1593 components: &[&str], is_value: bool) -> hir::Path {
1594 let mut path = hir::Path {
1597 segments: iter::once(keywords::CrateRoot.name()).chain({
1598 crate_root.into_iter().chain(components.iter().cloned()).map(Symbol::intern)
1599 }).map(hir::PathSegment::from_name).collect(),
1602 self.resolve_hir_path(&mut path, is_value);
1606 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1607 self.def_map.get(&id).cloned()
1610 fn definitions(&mut self) -> &mut Definitions {
1611 &mut self.definitions
1615 impl<'a> Resolver<'a> {
1616 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1617 /// isn't something that can be returned because it can't be made to live that long,
1618 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1619 /// just that an error occurred.
1620 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1621 -> Result<hir::Path, ()> {
1623 let mut errored = false;
1625 let mut path = if path_str.starts_with("::") {
1629 segments: iter::once(keywords::CrateRoot.name()).chain({
1630 path_str.split("::").skip(1).map(Symbol::intern)
1631 }).map(hir::PathSegment::from_name).collect(),
1637 segments: path_str.split("::").map(Symbol::intern)
1638 .map(hir::PathSegment::from_name).collect(),
1641 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1642 if errored || path.def == Def::Err {
1649 /// resolve_hir_path, but takes a callback in case there was an error
1650 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1651 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1653 let namespace = if is_value { ValueNS } else { TypeNS };
1654 let hir::Path { ref segments, span, ref mut def } = *path;
1655 let path: Vec<Ident> = segments.iter()
1656 .map(|seg| Ident::new(seg.name, span))
1658 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1659 match self.resolve_path(&path, Some(namespace), true, span, None) {
1660 PathResult::Module(module) => *def = module.def().unwrap(),
1661 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1662 *def = path_res.base_def(),
1663 PathResult::NonModule(..) => match self.resolve_path(&path, None, true, span, None) {
1664 PathResult::Failed(span, msg, _) => {
1665 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1669 PathResult::Indeterminate => unreachable!(),
1670 PathResult::Failed(span, msg, _) => {
1671 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1677 impl<'a> Resolver<'a> {
1678 pub fn new(session: &'a Session,
1679 cstore: &'a CrateStore,
1682 make_glob_map: MakeGlobMap,
1683 crate_loader: &'a mut CrateLoader,
1684 arenas: &'a ResolverArenas<'a>)
1686 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1687 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1688 let graph_root = arenas.alloc_module(ModuleData {
1689 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1690 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1692 let mut module_map = FxHashMap();
1693 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1695 let mut definitions = Definitions::new();
1696 DefCollector::new(&mut definitions, Mark::root())
1697 .collect_root(crate_name, session.local_crate_disambiguator());
1699 let mut invocations = FxHashMap();
1700 invocations.insert(Mark::root(),
1701 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1703 let features = session.features_untracked();
1705 let mut macro_defs = FxHashMap();
1706 macro_defs.insert(Mark::root(), root_def_id);
1715 // The outermost module has def ID 0; this is not reflected in the
1719 extern_prelude: session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect(),
1721 has_self: FxHashSet(),
1722 field_names: FxHashMap(),
1724 determined_imports: Vec::new(),
1725 indeterminate_imports: Vec::new(),
1727 current_module: graph_root,
1729 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1730 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1731 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1733 label_ribs: Vec::new(),
1735 current_trait_ref: None,
1736 current_self_type: None,
1738 primitive_type_table: PrimitiveTypeTable::new(),
1741 freevars: NodeMap(),
1742 freevars_seen: NodeMap(),
1743 export_map: FxHashMap(),
1744 trait_map: NodeMap(),
1746 block_map: NodeMap(),
1747 extern_module_map: FxHashMap(),
1749 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1750 glob_map: NodeMap(),
1752 used_imports: FxHashSet(),
1753 maybe_unused_trait_imports: NodeSet(),
1754 maybe_unused_extern_crates: Vec::new(),
1756 privacy_errors: Vec::new(),
1757 ambiguity_errors: Vec::new(),
1758 use_injections: Vec::new(),
1759 proc_mac_errors: Vec::new(),
1760 gated_errors: FxHashSet(),
1761 disallowed_shadowing: Vec::new(),
1764 dummy_binding: arenas.alloc_name_binding(NameBinding {
1765 kind: NameBindingKind::Def(Def::Err),
1766 expansion: Mark::root(),
1768 vis: ty::Visibility::Public,
1771 // The `proc_macro` and `decl_macro` features imply `use_extern_macros`
1773 features.use_extern_macros || features.proc_macro || features.decl_macro,
1776 macro_names: FxHashSet(),
1777 global_macros: FxHashMap(),
1778 all_macros: FxHashMap(),
1779 lexical_macro_resolutions: Vec::new(),
1780 macro_map: FxHashMap(),
1781 macro_exports: Vec::new(),
1784 local_macro_def_scopes: FxHashMap(),
1785 name_already_seen: FxHashMap(),
1786 whitelisted_legacy_custom_derives: Vec::new(),
1787 proc_macro_enabled: features.proc_macro,
1788 warned_proc_macros: FxHashSet(),
1789 potentially_unused_imports: Vec::new(),
1790 struct_constructors: DefIdMap(),
1791 found_unresolved_macro: false,
1792 unused_macros: FxHashSet(),
1793 current_type_ascription: Vec::new(),
1794 injected_crate: None,
1798 pub fn arenas() -> ResolverArenas<'a> {
1800 modules: arena::TypedArena::new(),
1801 local_modules: RefCell::new(Vec::new()),
1802 name_bindings: arena::TypedArena::new(),
1803 import_directives: arena::TypedArena::new(),
1804 name_resolutions: arena::TypedArena::new(),
1805 invocation_data: arena::TypedArena::new(),
1806 legacy_bindings: arena::TypedArena::new(),
1810 /// Runs the function on each namespace.
1811 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1814 if self.use_extern_macros {
1819 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1821 match self.macro_defs.get(&ctxt.outer()) {
1822 Some(&def_id) => return def_id,
1823 None => ctxt.remove_mark(),
1828 /// Entry point to crate resolution.
1829 pub fn resolve_crate(&mut self, krate: &Crate) {
1830 ImportResolver { resolver: self }.finalize_imports();
1831 self.current_module = self.graph_root;
1832 self.finalize_current_module_macro_resolutions();
1834 visit::walk_crate(self, krate);
1836 check_unused::check_crate(self, krate);
1837 self.report_errors(krate);
1838 self.crate_loader.postprocess(krate);
1845 normal_ancestor_id: DefId,
1849 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1850 self.arenas.alloc_module(module)
1853 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>, span: Span)
1854 -> bool /* true if an error was reported */ {
1855 match binding.kind {
1856 NameBindingKind::Import { directive, binding, ref used, legacy_self_import }
1859 directive.used.set(true);
1860 if legacy_self_import {
1861 self.warn_legacy_self_import(directive);
1864 self.used_imports.insert((directive.id, ns));
1865 self.add_to_glob_map(directive.id, ident);
1866 self.record_use(ident, ns, binding, span)
1868 NameBindingKind::Import { .. } => false,
1869 NameBindingKind::Ambiguity { b1, b2, legacy } => {
1870 self.ambiguity_errors.push(AmbiguityError {
1871 span: span, name: ident.name, lexical: false, b1: b1, b2: b2, legacy,
1874 self.record_use(ident, ns, b1, span);
1882 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1883 if self.make_glob_map {
1884 self.glob_map.entry(id).or_insert_with(FxHashSet).insert(ident.name);
1888 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1889 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1890 /// `ident` in the first scope that defines it (or None if no scopes define it).
1892 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1893 /// the items are defined in the block. For example,
1896 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1899 /// g(); // This resolves to the local variable `g` since it shadows the item.
1903 /// Invariant: This must only be called during main resolution, not during
1904 /// import resolution.
1905 fn resolve_ident_in_lexical_scope(&mut self,
1910 -> Option<LexicalScopeBinding<'a>> {
1912 ident.span = if ident.name == keywords::SelfType.name() {
1913 // FIXME(jseyfried) improve `Self` hygiene
1914 ident.span.with_ctxt(SyntaxContext::empty())
1920 // Walk backwards up the ribs in scope.
1921 let mut module = self.graph_root;
1922 for i in (0 .. self.ribs[ns].len()).rev() {
1923 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1924 // The ident resolves to a type parameter or local variable.
1925 return Some(LexicalScopeBinding::Def(
1926 self.adjust_local_def(ns, i, def, record_used, path_span)
1930 module = match self.ribs[ns][i].kind {
1931 ModuleRibKind(module) => module,
1932 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1933 // If an invocation of this macro created `ident`, give up on `ident`
1934 // and switch to `ident`'s source from the macro definition.
1935 ident.span.remove_mark();
1941 let item = self.resolve_ident_in_module_unadjusted(
1942 module, ident, ns, false, record_used, path_span,
1944 if let Ok(binding) = item {
1945 // The ident resolves to an item.
1946 return Some(LexicalScopeBinding::Item(binding));
1950 ModuleKind::Block(..) => {}, // We can see through blocks
1955 ident.span = ident.span.modern();
1957 module = unwrap_or!(self.hygienic_lexical_parent(module, &mut ident.span), break);
1958 let orig_current_module = self.current_module;
1959 self.current_module = module; // Lexical resolutions can never be a privacy error.
1960 let result = self.resolve_ident_in_module_unadjusted(
1961 module, ident, ns, false, record_used, path_span,
1963 self.current_module = orig_current_module;
1966 Ok(binding) => return Some(LexicalScopeBinding::Item(binding)),
1967 Err(Undetermined) => return None,
1968 Err(Determined) => {}
1972 if !module.no_implicit_prelude {
1973 // `record_used` means that we don't try to load crates during speculative resolution
1974 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1975 if !self.session.features_untracked().extern_prelude {
1976 feature_err(&self.session.parse_sess, "extern_prelude",
1977 ident.span, GateIssue::Language,
1978 "access to extern crates through prelude is experimental").emit();
1981 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1982 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1983 self.populate_module_if_necessary(crate_root);
1985 let binding = (crate_root, ty::Visibility::Public,
1986 ident.span, Mark::root()).to_name_binding(self.arenas);
1987 return Some(LexicalScopeBinding::Item(binding));
1989 if let Some(prelude) = self.prelude {
1990 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(prelude, ident, ns,
1991 false, false, path_span) {
1992 return Some(LexicalScopeBinding::Item(binding));
2000 fn hygienic_lexical_parent(&mut self, mut module: Module<'a>, span: &mut Span)
2001 -> Option<Module<'a>> {
2002 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2003 return Some(self.macro_def_scope(span.remove_mark()));
2006 if let ModuleKind::Block(..) = module.kind {
2007 return Some(module.parent.unwrap());
2010 let mut module_expansion = module.expansion.modern(); // for backward compatibility
2011 while let Some(parent) = module.parent {
2012 let parent_expansion = parent.expansion.modern();
2013 if module_expansion.is_descendant_of(parent_expansion) &&
2014 parent_expansion != module_expansion {
2015 return if parent_expansion.is_descendant_of(span.ctxt().outer()) {
2022 module_expansion = parent_expansion;
2028 fn resolve_ident_in_module(&mut self,
2032 ignore_unresolved_invocations: bool,
2035 -> Result<&'a NameBinding<'a>, Determinacy> {
2036 ident.span = ident.span.modern();
2037 let orig_current_module = self.current_module;
2038 if let Some(def) = ident.span.adjust(module.expansion) {
2039 self.current_module = self.macro_def_scope(def);
2041 let result = self.resolve_ident_in_module_unadjusted(
2042 module, ident, ns, ignore_unresolved_invocations, record_used, span,
2044 self.current_module = orig_current_module;
2048 fn resolve_crate_root(&mut self, mut ctxt: SyntaxContext, legacy: bool) -> Module<'a> {
2049 let mark = if legacy {
2050 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2051 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2052 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2053 ctxt.marks().into_iter().find(|&mark| mark.kind() != MarkKind::Modern)
2055 ctxt = ctxt.modern();
2056 ctxt.adjust(Mark::root())
2058 let module = match mark {
2059 Some(def) => self.macro_def_scope(def),
2060 None => return self.graph_root,
2062 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2065 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2066 let mut module = self.get_module(module.normal_ancestor_id);
2067 while module.span.ctxt().modern() != *ctxt {
2068 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2069 module = self.get_module(parent.normal_ancestor_id);
2076 // We maintain a list of value ribs and type ribs.
2078 // Simultaneously, we keep track of the current position in the module
2079 // graph in the `current_module` pointer. When we go to resolve a name in
2080 // the value or type namespaces, we first look through all the ribs and
2081 // then query the module graph. When we resolve a name in the module
2082 // namespace, we can skip all the ribs (since nested modules are not
2083 // allowed within blocks in Rust) and jump straight to the current module
2086 // Named implementations are handled separately. When we find a method
2087 // call, we consult the module node to find all of the implementations in
2088 // scope. This information is lazily cached in the module node. We then
2089 // generate a fake "implementation scope" containing all the
2090 // implementations thus found, for compatibility with old resolve pass.
2092 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2093 where F: FnOnce(&mut Resolver) -> T
2095 let id = self.definitions.local_def_id(id);
2096 let module = self.module_map.get(&id).cloned(); // clones a reference
2097 if let Some(module) = module {
2098 // Move down in the graph.
2099 let orig_module = replace(&mut self.current_module, module);
2100 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2101 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2103 self.finalize_current_module_macro_resolutions();
2106 self.current_module = orig_module;
2107 self.ribs[ValueNS].pop();
2108 self.ribs[TypeNS].pop();
2115 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2116 /// is returned by the given predicate function
2118 /// Stops after meeting a closure.
2119 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2120 where P: Fn(&Rib, Ident) -> Option<R>
2122 for rib in self.label_ribs.iter().rev() {
2125 // If an invocation of this macro created `ident`, give up on `ident`
2126 // and switch to `ident`'s source from the macro definition.
2127 MacroDefinition(def) => {
2128 if def == self.macro_def(ident.span.ctxt()) {
2129 ident.span.remove_mark();
2133 // Do not resolve labels across function boundary
2137 let r = pred(rib, ident);
2145 fn resolve_item(&mut self, item: &Item) {
2146 let name = item.ident.name;
2148 debug!("(resolving item) resolving {}", name);
2150 self.check_proc_macro_attrs(&item.attrs);
2153 ItemKind::Enum(_, ref generics) |
2154 ItemKind::Ty(_, ref generics) |
2155 ItemKind::Struct(_, ref generics) |
2156 ItemKind::Union(_, ref generics) |
2157 ItemKind::Fn(.., ref generics, _) => {
2158 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2159 |this| visit::walk_item(this, item));
2162 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2163 self.resolve_implementation(generics,
2169 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2170 // Create a new rib for the trait-wide type parameters.
2171 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2172 let local_def_id = this.definitions.local_def_id(item.id);
2173 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2174 this.visit_generics(generics);
2175 walk_list!(this, visit_ty_param_bound, bounds);
2177 for trait_item in trait_items {
2178 this.check_proc_macro_attrs(&trait_item.attrs);
2180 let type_parameters = HasTypeParameters(&trait_item.generics,
2181 TraitOrImplItemRibKind);
2182 this.with_type_parameter_rib(type_parameters, |this| {
2183 match trait_item.node {
2184 TraitItemKind::Const(ref ty, ref default) => {
2187 // Only impose the restrictions of
2188 // ConstRibKind for an actual constant
2189 // expression in a provided default.
2190 if let Some(ref expr) = *default{
2191 this.with_constant_rib(|this| {
2192 this.visit_expr(expr);
2196 TraitItemKind::Method(_, _) => {
2197 visit::walk_trait_item(this, trait_item)
2199 TraitItemKind::Type(..) => {
2200 visit::walk_trait_item(this, trait_item)
2202 TraitItemKind::Macro(_) => {
2203 panic!("unexpanded macro in resolve!")
2212 ItemKind::TraitAlias(ref generics, ref bounds) => {
2213 // Create a new rib for the trait-wide type parameters.
2214 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2215 let local_def_id = this.definitions.local_def_id(item.id);
2216 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2217 this.visit_generics(generics);
2218 walk_list!(this, visit_ty_param_bound, bounds);
2223 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2224 self.with_scope(item.id, |this| {
2225 visit::walk_item(this, item);
2229 ItemKind::Static(ref ty, _, ref expr) |
2230 ItemKind::Const(ref ty, ref expr) => {
2231 self.with_item_rib(|this| {
2233 this.with_constant_rib(|this| {
2234 this.visit_expr(expr);
2239 ItemKind::Use(ref use_tree) => {
2240 // Imports are resolved as global by default, add starting root segment.
2242 segments: use_tree.prefix.make_root().into_iter().collect(),
2243 span: use_tree.span,
2245 self.resolve_use_tree(item.id, use_tree, &path);
2248 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2249 // do nothing, these are just around to be encoded
2252 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2256 fn resolve_use_tree(&mut self, id: NodeId, use_tree: &ast::UseTree, prefix: &Path) {
2257 match use_tree.kind {
2258 ast::UseTreeKind::Nested(ref items) => {
2260 segments: prefix.segments
2262 .chain(use_tree.prefix.segments.iter())
2265 span: prefix.span.to(use_tree.prefix.span),
2268 if items.len() == 0 {
2269 // Resolve prefix of an import with empty braces (issue #28388).
2270 self.smart_resolve_path(id, None, &path, PathSource::ImportPrefix);
2272 for &(ref tree, nested_id) in items {
2273 self.resolve_use_tree(nested_id, tree, &path);
2277 ast::UseTreeKind::Simple(_) => {},
2278 ast::UseTreeKind::Glob => {},
2282 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2283 where F: FnOnce(&mut Resolver)
2285 match type_parameters {
2286 HasTypeParameters(generics, rib_kind) => {
2287 let mut function_type_rib = Rib::new(rib_kind);
2288 let mut seen_bindings = FxHashMap();
2289 for param in &generics.params {
2290 if let GenericParam::Type(ref type_parameter) = *param {
2291 let ident = type_parameter.ident.modern();
2292 debug!("with_type_parameter_rib: {}", type_parameter.id);
2294 if seen_bindings.contains_key(&ident) {
2295 let span = seen_bindings.get(&ident).unwrap();
2296 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2300 resolve_error(self, type_parameter.ident.span, err);
2302 seen_bindings.entry(ident).or_insert(type_parameter.ident.span);
2304 // plain insert (no renaming)
2305 let def_id = self.definitions.local_def_id(type_parameter.id);
2306 let def = Def::TyParam(def_id);
2307 function_type_rib.bindings.insert(ident, def);
2308 self.record_def(type_parameter.id, PathResolution::new(def));
2311 self.ribs[TypeNS].push(function_type_rib);
2314 NoTypeParameters => {
2321 if let HasTypeParameters(..) = type_parameters {
2322 self.ribs[TypeNS].pop();
2326 fn with_label_rib<F>(&mut self, f: F)
2327 where F: FnOnce(&mut Resolver)
2329 self.label_ribs.push(Rib::new(NormalRibKind));
2331 self.label_ribs.pop();
2334 fn with_item_rib<F>(&mut self, f: F)
2335 where F: FnOnce(&mut Resolver)
2337 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2338 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2340 self.ribs[TypeNS].pop();
2341 self.ribs[ValueNS].pop();
2344 fn with_constant_rib<F>(&mut self, f: F)
2345 where F: FnOnce(&mut Resolver)
2347 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2349 self.ribs[ValueNS].pop();
2352 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2353 where F: FnOnce(&mut Resolver) -> T
2355 // Handle nested impls (inside fn bodies)
2356 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2357 let result = f(self);
2358 self.current_self_type = previous_value;
2362 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2363 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2364 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2366 let mut new_val = None;
2367 let mut new_id = None;
2368 if let Some(trait_ref) = opt_trait_ref {
2369 let path: Vec<_> = trait_ref.path.segments.iter()
2370 .map(|seg| seg.ident)
2372 let def = self.smart_resolve_path_fragment(
2376 trait_ref.path.span,
2377 PathSource::Trait(AliasPossibility::No)
2379 if def != Def::Err {
2380 new_id = Some(def.def_id());
2381 let span = trait_ref.path.span;
2382 if let PathResult::Module(module) = self.resolve_path(&path, None, false, span,
2383 Some(trait_ref.ref_id)) {
2384 new_val = Some((module, trait_ref.clone()));
2388 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2389 let result = f(self, new_id);
2390 self.current_trait_ref = original_trait_ref;
2394 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2395 where F: FnOnce(&mut Resolver)
2397 let mut self_type_rib = Rib::new(NormalRibKind);
2399 // plain insert (no renaming, types are not currently hygienic....)
2400 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2401 self.ribs[TypeNS].push(self_type_rib);
2403 self.ribs[TypeNS].pop();
2406 fn resolve_implementation(&mut self,
2407 generics: &Generics,
2408 opt_trait_reference: &Option<TraitRef>,
2411 impl_items: &[ImplItem]) {
2412 // If applicable, create a rib for the type parameters.
2413 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2414 // Dummy self type for better errors if `Self` is used in the trait path.
2415 this.with_self_rib(Def::SelfTy(None, None), |this| {
2416 // Resolve the trait reference, if necessary.
2417 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2418 let item_def_id = this.definitions.local_def_id(item_id);
2419 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2420 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2421 // Resolve type arguments in trait path
2422 visit::walk_trait_ref(this, trait_ref);
2424 // Resolve the self type.
2425 this.visit_ty(self_type);
2426 // Resolve the type parameters.
2427 this.visit_generics(generics);
2428 this.with_current_self_type(self_type, |this| {
2429 for impl_item in impl_items {
2430 this.check_proc_macro_attrs(&impl_item.attrs);
2431 this.resolve_visibility(&impl_item.vis);
2433 // We also need a new scope for the impl item type parameters.
2434 let type_parameters = HasTypeParameters(&impl_item.generics,
2435 TraitOrImplItemRibKind);
2436 this.with_type_parameter_rib(type_parameters, |this| {
2437 use self::ResolutionError::*;
2438 match impl_item.node {
2439 ImplItemKind::Const(..) => {
2440 // If this is a trait impl, ensure the const
2442 this.check_trait_item(impl_item.ident,
2445 |n, s| ConstNotMemberOfTrait(n, s));
2446 this.with_constant_rib(|this|
2447 visit::walk_impl_item(this, impl_item)
2450 ImplItemKind::Method(_, _) => {
2451 // If this is a trait impl, ensure the method
2453 this.check_trait_item(impl_item.ident,
2456 |n, s| MethodNotMemberOfTrait(n, s));
2458 visit::walk_impl_item(this, impl_item);
2460 ImplItemKind::Type(ref ty) => {
2461 // If this is a trait impl, ensure the type
2463 this.check_trait_item(impl_item.ident,
2466 |n, s| TypeNotMemberOfTrait(n, s));
2470 ImplItemKind::Macro(_) =>
2471 panic!("unexpanded macro in resolve!"),
2482 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2483 where F: FnOnce(Name, &str) -> ResolutionError
2485 // If there is a TraitRef in scope for an impl, then the method must be in the
2487 if let Some((module, _)) = self.current_trait_ref {
2488 if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
2489 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2490 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2495 fn resolve_local(&mut self, local: &Local) {
2496 // Resolve the type.
2497 walk_list!(self, visit_ty, &local.ty);
2499 // Resolve the initializer.
2500 walk_list!(self, visit_expr, &local.init);
2502 // Resolve the pattern.
2503 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2506 // build a map from pattern identifiers to binding-info's.
2507 // this is done hygienically. This could arise for a macro
2508 // that expands into an or-pattern where one 'x' was from the
2509 // user and one 'x' came from the macro.
2510 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2511 let mut binding_map = FxHashMap();
2513 pat.walk(&mut |pat| {
2514 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2515 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2516 Some(Def::Local(..)) => true,
2519 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2520 binding_map.insert(ident, binding_info);
2529 // check that all of the arms in an or-pattern have exactly the
2530 // same set of bindings, with the same binding modes for each.
2531 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2532 if pats.is_empty() {
2536 let mut missing_vars = FxHashMap();
2537 let mut inconsistent_vars = FxHashMap();
2538 for (i, p) in pats.iter().enumerate() {
2539 let map_i = self.binding_mode_map(&p);
2541 for (j, q) in pats.iter().enumerate() {
2546 let map_j = self.binding_mode_map(&q);
2547 for (&key, &binding_i) in &map_i {
2548 if map_j.len() == 0 { // Account for missing bindings when
2549 let binding_error = missing_vars // map_j has none.
2551 .or_insert(BindingError {
2553 origin: BTreeSet::new(),
2554 target: BTreeSet::new(),
2556 binding_error.origin.insert(binding_i.span);
2557 binding_error.target.insert(q.span);
2559 for (&key_j, &binding_j) in &map_j {
2560 match map_i.get(&key_j) {
2561 None => { // missing binding
2562 let binding_error = missing_vars
2564 .or_insert(BindingError {
2566 origin: BTreeSet::new(),
2567 target: BTreeSet::new(),
2569 binding_error.origin.insert(binding_j.span);
2570 binding_error.target.insert(p.span);
2572 Some(binding_i) => { // check consistent binding
2573 if binding_i.binding_mode != binding_j.binding_mode {
2576 .or_insert((binding_j.span, binding_i.span));
2584 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2585 missing_vars.sort();
2586 for (_, v) in missing_vars {
2588 *v.origin.iter().next().unwrap(),
2589 ResolutionError::VariableNotBoundInPattern(v));
2591 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2592 inconsistent_vars.sort();
2593 for (name, v) in inconsistent_vars {
2594 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2598 fn resolve_arm(&mut self, arm: &Arm) {
2599 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2601 let mut bindings_list = FxHashMap();
2602 for pattern in &arm.pats {
2603 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2606 // This has to happen *after* we determine which pat_idents are variants
2607 self.check_consistent_bindings(&arm.pats);
2609 walk_list!(self, visit_expr, &arm.guard);
2610 self.visit_expr(&arm.body);
2612 self.ribs[ValueNS].pop();
2615 fn resolve_block(&mut self, block: &Block) {
2616 debug!("(resolving block) entering block");
2617 // Move down in the graph, if there's an anonymous module rooted here.
2618 let orig_module = self.current_module;
2619 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2621 let mut num_macro_definition_ribs = 0;
2622 if let Some(anonymous_module) = anonymous_module {
2623 debug!("(resolving block) found anonymous module, moving down");
2624 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2625 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2626 self.current_module = anonymous_module;
2627 self.finalize_current_module_macro_resolutions();
2629 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2632 // Descend into the block.
2633 for stmt in &block.stmts {
2634 if let ast::StmtKind::Item(ref item) = stmt.node {
2635 if let ast::ItemKind::MacroDef(..) = item.node {
2636 num_macro_definition_ribs += 1;
2637 let def = self.definitions.local_def_id(item.id);
2638 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2639 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2643 self.visit_stmt(stmt);
2647 self.current_module = orig_module;
2648 for _ in 0 .. num_macro_definition_ribs {
2649 self.ribs[ValueNS].pop();
2650 self.label_ribs.pop();
2652 self.ribs[ValueNS].pop();
2653 if let Some(_) = anonymous_module {
2654 self.ribs[TypeNS].pop();
2656 debug!("(resolving block) leaving block");
2659 fn fresh_binding(&mut self,
2662 outer_pat_id: NodeId,
2663 pat_src: PatternSource,
2664 bindings: &mut FxHashMap<Ident, NodeId>)
2666 // Add the binding to the local ribs, if it
2667 // doesn't already exist in the bindings map. (We
2668 // must not add it if it's in the bindings map
2669 // because that breaks the assumptions later
2670 // passes make about or-patterns.)
2671 let mut def = Def::Local(pat_id);
2672 match bindings.get(&ident).cloned() {
2673 Some(id) if id == outer_pat_id => {
2674 // `Variant(a, a)`, error
2678 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2679 &ident.name.as_str())
2682 Some(..) if pat_src == PatternSource::FnParam => {
2683 // `fn f(a: u8, a: u8)`, error
2687 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2688 &ident.name.as_str())
2691 Some(..) if pat_src == PatternSource::Match ||
2692 pat_src == PatternSource::IfLet ||
2693 pat_src == PatternSource::WhileLet => {
2694 // `Variant1(a) | Variant2(a)`, ok
2695 // Reuse definition from the first `a`.
2696 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2699 span_bug!(ident.span, "two bindings with the same name from \
2700 unexpected pattern source {:?}", pat_src);
2703 // A completely fresh binding, add to the lists if it's valid.
2704 if ident.name != keywords::Invalid.name() {
2705 bindings.insert(ident, outer_pat_id);
2706 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2711 PathResolution::new(def)
2714 fn resolve_pattern(&mut self,
2716 pat_src: PatternSource,
2717 // Maps idents to the node ID for the
2718 // outermost pattern that binds them.
2719 bindings: &mut FxHashMap<Ident, NodeId>) {
2720 // Visit all direct subpatterns of this pattern.
2721 let outer_pat_id = pat.id;
2722 pat.walk(&mut |pat| {
2724 PatKind::Ident(bmode, ident, ref opt_pat) => {
2725 // First try to resolve the identifier as some existing
2726 // entity, then fall back to a fresh binding.
2727 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2729 .and_then(LexicalScopeBinding::item);
2730 let resolution = binding.map(NameBinding::def).and_then(|def| {
2731 let is_syntactic_ambiguity = opt_pat.is_none() &&
2732 bmode == BindingMode::ByValue(Mutability::Immutable);
2734 Def::StructCtor(_, CtorKind::Const) |
2735 Def::VariantCtor(_, CtorKind::Const) |
2736 Def::Const(..) if is_syntactic_ambiguity => {
2737 // Disambiguate in favor of a unit struct/variant
2738 // or constant pattern.
2739 self.record_use(ident, ValueNS, binding.unwrap(), ident.span);
2740 Some(PathResolution::new(def))
2742 Def::StructCtor(..) | Def::VariantCtor(..) |
2743 Def::Const(..) | Def::Static(..) => {
2744 // This is unambiguously a fresh binding, either syntactically
2745 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2746 // to something unusable as a pattern (e.g. constructor function),
2747 // but we still conservatively report an error, see
2748 // issues/33118#issuecomment-233962221 for one reason why.
2752 ResolutionError::BindingShadowsSomethingUnacceptable(
2753 pat_src.descr(), ident.name, binding.unwrap())
2757 Def::Fn(..) | Def::Err => {
2758 // These entities are explicitly allowed
2759 // to be shadowed by fresh bindings.
2763 span_bug!(ident.span, "unexpected definition for an \
2764 identifier in pattern: {:?}", def);
2767 }).unwrap_or_else(|| {
2768 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2771 self.record_def(pat.id, resolution);
2774 PatKind::TupleStruct(ref path, ..) => {
2775 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2778 PatKind::Path(ref qself, ref path) => {
2779 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2782 PatKind::Struct(ref path, ..) => {
2783 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2791 visit::walk_pat(self, pat);
2794 // High-level and context dependent path resolution routine.
2795 // Resolves the path and records the resolution into definition map.
2796 // If resolution fails tries several techniques to find likely
2797 // resolution candidates, suggest imports or other help, and report
2798 // errors in user friendly way.
2799 fn smart_resolve_path(&mut self,
2801 qself: Option<&QSelf>,
2805 let segments = &path.segments.iter()
2806 .map(|seg| seg.ident)
2807 .collect::<Vec<_>>();
2808 self.smart_resolve_path_fragment(id, qself, segments, path.span, source)
2811 fn smart_resolve_path_fragment(&mut self,
2813 qself: Option<&QSelf>,
2818 let ident_span = path.last().map_or(span, |ident| ident.span);
2819 let ns = source.namespace();
2820 let is_expected = &|def| source.is_expected(def);
2821 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2823 // Base error is amended with one short label and possibly some longer helps/notes.
2824 let report_errors = |this: &mut Self, def: Option<Def>| {
2825 // Make the base error.
2826 let expected = source.descr_expected();
2827 let path_str = names_to_string(path);
2828 let code = source.error_code(def.is_some());
2829 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2830 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2831 format!("not a {}", expected),
2834 let item_str = path[path.len() - 1];
2835 let item_span = path[path.len() - 1].span;
2836 let (mod_prefix, mod_str) = if path.len() == 1 {
2837 (format!(""), format!("this scope"))
2838 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2839 (format!(""), format!("the crate root"))
2841 let mod_path = &path[..path.len() - 1];
2842 let mod_prefix = match this.resolve_path(mod_path, Some(TypeNS),
2843 false, span, None) {
2844 PathResult::Module(module) => module.def(),
2846 }.map_or(format!(""), |def| format!("{} ", def.kind_name()));
2847 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2849 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2850 format!("not found in {}", mod_str),
2853 let code = DiagnosticId::Error(code.into());
2854 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2856 // Emit special messages for unresolved `Self` and `self`.
2857 if is_self_type(path, ns) {
2858 __diagnostic_used!(E0411);
2859 err.code(DiagnosticId::Error("E0411".into()));
2860 err.span_label(span, "`Self` is only available in traits and impls");
2861 return (err, Vec::new());
2863 if is_self_value(path, ns) {
2864 __diagnostic_used!(E0424);
2865 err.code(DiagnosticId::Error("E0424".into()));
2866 err.span_label(span, format!("`self` value is only available in \
2867 methods with `self` parameter"));
2868 return (err, Vec::new());
2871 // Try to lookup the name in more relaxed fashion for better error reporting.
2872 let ident = *path.last().unwrap();
2873 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
2874 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
2875 let enum_candidates =
2876 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
2877 let mut enum_candidates = enum_candidates.iter()
2878 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
2879 enum_candidates.sort();
2880 for (sp, variant_path, enum_path) in enum_candidates {
2882 let msg = format!("there is an enum variant `{}`, \
2888 err.span_suggestion(span, "you can try using the variant's enum",
2893 if path.len() == 1 && this.self_type_is_available(span) {
2894 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
2895 let self_is_available = this.self_value_is_available(path[0].span, span);
2897 AssocSuggestion::Field => {
2898 err.span_suggestion(span, "try",
2899 format!("self.{}", path_str));
2900 if !self_is_available {
2901 err.span_label(span, format!("`self` value is only available in \
2902 methods with `self` parameter"));
2905 AssocSuggestion::MethodWithSelf if self_is_available => {
2906 err.span_suggestion(span, "try",
2907 format!("self.{}", path_str));
2909 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
2910 err.span_suggestion(span, "try",
2911 format!("Self::{}", path_str));
2914 return (err, candidates);
2918 let mut levenshtein_worked = false;
2921 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
2922 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
2923 levenshtein_worked = true;
2926 // Try context dependent help if relaxed lookup didn't work.
2927 if let Some(def) = def {
2928 match (def, source) {
2929 (Def::Macro(..), _) => {
2930 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
2931 return (err, candidates);
2933 (Def::TyAlias(..), PathSource::Trait(_)) => {
2934 err.span_label(span, "type aliases cannot be used for traits");
2935 return (err, candidates);
2937 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
2938 ExprKind::Field(_, ident) => {
2939 err.span_label(parent.span, format!("did you mean `{}::{}`?",
2941 return (err, candidates);
2943 ExprKind::MethodCall(ref segment, ..) => {
2944 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
2945 path_str, segment.ident));
2946 return (err, candidates);
2950 (Def::Enum(..), PathSource::TupleStruct)
2951 | (Def::Enum(..), PathSource::Expr(..)) => {
2952 if let Some(variants) = this.collect_enum_variants(def) {
2953 err.note(&format!("did you mean to use one \
2954 of the following variants?\n{}",
2956 .map(|suggestion| path_names_to_string(suggestion))
2957 .map(|suggestion| format!("- `{}`", suggestion))
2958 .collect::<Vec<_>>()
2962 err.note("did you mean to use one of the enum's variants?");
2964 return (err, candidates);
2966 (Def::Struct(def_id), _) if ns == ValueNS => {
2967 if let Some((ctor_def, ctor_vis))
2968 = this.struct_constructors.get(&def_id).cloned() {
2969 let accessible_ctor = this.is_accessible(ctor_vis);
2970 if is_expected(ctor_def) && !accessible_ctor {
2971 err.span_label(span, format!("constructor is not visible \
2972 here due to private fields"));
2975 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2978 return (err, candidates);
2980 (Def::Union(..), _) |
2981 (Def::Variant(..), _) |
2982 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
2983 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
2985 return (err, candidates);
2987 (Def::SelfTy(..), _) if ns == ValueNS => {
2988 err.span_label(span, fallback_label);
2989 err.note("can't use `Self` as a constructor, you must use the \
2990 implemented struct");
2991 return (err, candidates);
2993 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
2994 err.note("can't use a type alias as a constructor");
2995 return (err, candidates);
3002 if !levenshtein_worked {
3003 err.span_label(base_span, fallback_label);
3004 this.type_ascription_suggestion(&mut err, base_span);
3008 let report_errors = |this: &mut Self, def: Option<Def>| {
3009 let (err, candidates) = report_errors(this, def);
3010 let def_id = this.current_module.normal_ancestor_id;
3011 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3012 let better = def.is_some();
3013 this.use_injections.push(UseError { err, candidates, node_id, better });
3014 err_path_resolution()
3017 let resolution = match self.resolve_qpath_anywhere(id, qself, path, ns, span,
3018 source.defer_to_typeck(),
3019 source.global_by_default()) {
3020 Some(resolution) if resolution.unresolved_segments() == 0 => {
3021 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3024 // Add a temporary hack to smooth the transition to new struct ctor
3025 // visibility rules. See #38932 for more details.
3027 if let Def::Struct(def_id) = resolution.base_def() {
3028 if let Some((ctor_def, ctor_vis))
3029 = self.struct_constructors.get(&def_id).cloned() {
3030 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3031 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3032 self.session.buffer_lint(lint, id, span,
3033 "private struct constructors are not usable through \
3034 re-exports in outer modules",
3036 res = Some(PathResolution::new(ctor_def));
3041 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3044 Some(resolution) if source.defer_to_typeck() => {
3045 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3046 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3047 // it needs to be added to the trait map.
3049 let item_name = *path.last().unwrap();
3050 let traits = self.get_traits_containing_item(item_name, ns);
3051 self.trait_map.insert(id, traits);
3055 _ => report_errors(self, None)
3058 if let PathSource::TraitItem(..) = source {} else {
3059 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3060 self.record_def(id, resolution);
3065 fn type_ascription_suggestion(&self,
3066 err: &mut DiagnosticBuilder,
3068 debug!("type_ascription_suggetion {:?}", base_span);
3069 let cm = self.session.codemap();
3070 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3071 if let Some(sp) = self.current_type_ascription.last() {
3073 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3074 sp = cm.next_point(sp);
3075 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3076 debug!("snippet {:?}", snippet);
3077 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3078 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3079 debug!("{:?} {:?}", line_sp, line_base_sp);
3081 err.span_label(base_span,
3082 "expecting a type here because of type ascription");
3083 if line_sp != line_base_sp {
3084 err.span_suggestion_short(sp,
3085 "did you mean to use `;` here instead?",
3089 } else if snippet.trim().len() != 0 {
3090 debug!("tried to find type ascription `:` token, couldn't find it");
3100 fn self_type_is_available(&mut self, span: Span) -> bool {
3101 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3102 TypeNS, false, span);
3103 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3106 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3107 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3108 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, false, path_span);
3109 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3112 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3113 fn resolve_qpath_anywhere(&mut self,
3115 qself: Option<&QSelf>,
3117 primary_ns: Namespace,
3119 defer_to_typeck: bool,
3120 global_by_default: bool)
3121 -> Option<PathResolution> {
3122 let mut fin_res = None;
3123 // FIXME: can't resolve paths in macro namespace yet, macros are
3124 // processed by the little special hack below.
3125 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3126 if i == 0 || ns != primary_ns {
3127 match self.resolve_qpath(id, qself, path, ns, span, global_by_default) {
3128 // If defer_to_typeck, then resolution > no resolution,
3129 // otherwise full resolution > partial resolution > no resolution.
3130 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3132 res => if fin_res.is_none() { fin_res = res },
3136 let is_global = self.global_macros.get(&path[0].name).cloned()
3137 .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
3138 if primary_ns != MacroNS && (is_global ||
3139 self.macro_names.contains(&path[0].modern())) {
3140 // Return some dummy definition, it's enough for error reporting.
3142 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3148 /// Handles paths that may refer to associated items.
3149 fn resolve_qpath(&mut self,
3151 qself: Option<&QSelf>,
3155 global_by_default: bool)
3156 -> Option<PathResolution> {
3157 if let Some(qself) = qself {
3158 if qself.position == 0 {
3159 // FIXME: Create some fake resolution that can't possibly be a type.
3160 return Some(PathResolution::with_unresolved_segments(
3161 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3164 // Make sure `A::B` in `<T as A>::B::C` is a trait item.
3165 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3166 let res = self.smart_resolve_path_fragment(id, None, &path[..qself.position + 1],
3167 span, PathSource::TraitItem(ns));
3168 return Some(PathResolution::with_unresolved_segments(
3169 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3173 let result = match self.resolve_path(&path, Some(ns), true, span, Some(id)) {
3174 PathResult::NonModule(path_res) => path_res,
3175 PathResult::Module(module) if !module.is_normal() => {
3176 PathResolution::new(module.def().unwrap())
3178 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3179 // don't report an error right away, but try to fallback to a primitive type.
3180 // So, we are still able to successfully resolve something like
3182 // use std::u8; // bring module u8 in scope
3183 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3184 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3185 // // not to non-existent std::u8::max_value
3188 // Such behavior is required for backward compatibility.
3189 // The same fallback is used when `a` resolves to nothing.
3190 PathResult::Module(..) | PathResult::Failed(..)
3191 if (ns == TypeNS || path.len() > 1) &&
3192 self.primitive_type_table.primitive_types
3193 .contains_key(&path[0].name) => {
3194 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3195 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3197 PathResult::Module(module) => PathResolution::new(module.def().unwrap()),
3198 PathResult::Failed(span, msg, false) => {
3199 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3200 err_path_resolution()
3202 PathResult::Failed(..) => return None,
3203 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3206 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3207 path[0].name != keywords::CrateRoot.name() &&
3208 path[0].name != keywords::DollarCrate.name() {
3209 let unqualified_result = {
3210 match self.resolve_path(&[*path.last().unwrap()], Some(ns), false, span, None) {
3211 PathResult::NonModule(path_res) => path_res.base_def(),
3212 PathResult::Module(module) => module.def().unwrap(),
3213 _ => return Some(result),
3216 if result.base_def() == unqualified_result {
3217 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3218 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3225 fn resolve_path(&mut self,
3227 opt_ns: Option<Namespace>, // `None` indicates a module path
3230 node_id: Option<NodeId>) // None indicates that we don't care about linting
3233 let mut module = None;
3234 let mut allow_super = true;
3236 for (i, &ident) in path.iter().enumerate() {
3237 debug!("resolve_path ident {} {:?}", i, ident);
3238 let is_last = i == path.len() - 1;
3239 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3240 let name = ident.name;
3242 if i == 0 && ns == TypeNS && name == keywords::SelfValue.name() {
3243 let mut ctxt = ident.span.ctxt().modern();
3244 module = Some(self.resolve_self(&mut ctxt, self.current_module));
3246 } else if allow_super && ns == TypeNS && name == keywords::Super.name() {
3247 let mut ctxt = ident.span.ctxt().modern();
3248 let self_module = match i {
3249 0 => self.resolve_self(&mut ctxt, self.current_module),
3250 _ => module.unwrap(),
3252 if let Some(parent) = self_module.parent {
3253 module = Some(self.resolve_self(&mut ctxt, parent));
3256 let msg = "There are too many initial `super`s.".to_string();
3257 return PathResult::Failed(ident.span, msg, false);
3259 } else if i == 0 && ns == TypeNS && name == keywords::Extern.name() {
3262 allow_super = false;
3265 if (i == 0 && name == keywords::CrateRoot.name()) ||
3266 (i == 0 && name == keywords::Crate.name()) ||
3267 (i == 1 && name == keywords::Crate.name() &&
3268 path[0].name == keywords::CrateRoot.name()) {
3269 // `::a::b` or `::crate::a::b`
3270 module = Some(self.resolve_crate_root(ident.span.ctxt(), false));
3272 } else if i == 0 && name == keywords::DollarCrate.name() {
3274 module = Some(self.resolve_crate_root(ident.span.ctxt(), true));
3276 } else if i == 1 && !token::is_path_segment_keyword(ident) {
3277 let prev_name = path[0].name;
3278 if prev_name == keywords::Extern.name() ||
3279 prev_name == keywords::CrateRoot.name() &&
3280 self.session.features_untracked().extern_absolute_paths &&
3281 self.session.rust_2018() {
3282 // `::extern_crate::a::b`
3283 let crate_id = self.crate_loader.process_path_extern(name, ident.span);
3285 self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3286 self.populate_module_if_necessary(crate_root);
3287 module = Some(crate_root);
3293 // Report special messages for path segment keywords in wrong positions.
3294 if name == keywords::CrateRoot.name() && i != 0 ||
3295 name == keywords::DollarCrate.name() && i != 0 ||
3296 name == keywords::SelfValue.name() && i != 0 ||
3297 name == keywords::SelfType.name() && i != 0 ||
3298 name == keywords::Super.name() && i != 0 ||
3299 name == keywords::Extern.name() && i != 0 ||
3300 // we allow crate::foo and ::crate::foo but nothing else
3301 name == keywords::Crate.name() && i > 1 &&
3302 path[0].name != keywords::CrateRoot.name() ||
3303 name == keywords::Crate.name() && path.len() == 1 {
3304 let name_str = if name == keywords::CrateRoot.name() {
3305 format!("crate root")
3307 format!("`{}`", name)
3309 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3310 format!("global paths cannot start with {}", name_str)
3312 format!("{} in paths can only be used in start position", name_str)
3314 return PathResult::Failed(ident.span, msg, false);
3317 let binding = if let Some(module) = module {
3318 self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
3319 } else if opt_ns == Some(MacroNS) {
3320 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
3321 .map(MacroBinding::binding)
3323 match self.resolve_ident_in_lexical_scope(ident, ns, record_used, path_span) {
3324 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3325 Some(LexicalScopeBinding::Def(def))
3326 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3327 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3331 _ => Err(if record_used { Determined } else { Undetermined }),
3337 let def = binding.def();
3338 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3339 if let Some(next_module) = binding.module() {
3340 module = Some(next_module);
3341 } else if def == Def::Err {
3342 return PathResult::NonModule(err_path_resolution());
3343 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3344 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3345 def, path.len() - i - 1
3348 return PathResult::Failed(ident.span,
3349 format!("Not a module `{}`", ident),
3353 if let Some(id) = node_id {
3354 if i == 1 && self.session.features_untracked().crate_in_paths
3355 && !self.session.rust_2018() {
3356 let prev_name = path[0].name;
3357 if prev_name == keywords::Extern.name() ||
3358 prev_name == keywords::CrateRoot.name() {
3359 let mut is_crate = false;
3360 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3361 if let ImportDirectiveSubclass::ExternCrate(..) = d.subclass {
3367 let diag = lint::builtin::BuiltinLintDiagnostics
3368 ::AbsPathWithModule(path_span);
3369 self.session.buffer_lint_with_diagnostic(
3370 lint::builtin::ABSOLUTE_PATH_STARTING_WITH_MODULE,
3372 "Absolute paths must start with `self`, `super`, \
3373 `crate`, or an external crate name in the 2018 edition",
3380 Err(Undetermined) => return PathResult::Indeterminate,
3381 Err(Determined) => {
3382 if let Some(module) = module {
3383 if opt_ns.is_some() && !module.is_normal() {
3384 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3385 module.def().unwrap(), path.len() - i
3389 let msg = if module.and_then(ModuleData::def) == self.graph_root.def() {
3390 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3391 let mut candidates =
3392 self.lookup_import_candidates(name, TypeNS, is_mod);
3393 candidates.sort_by_cached_key(|c| {
3394 (c.path.segments.len(), c.path.to_string())
3396 if let Some(candidate) = candidates.get(0) {
3397 format!("Did you mean `{}`?", candidate.path)
3399 format!("Maybe a missing `extern crate {};`?", ident)
3402 format!("Use of undeclared type or module `{}`", ident)
3404 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3406 return PathResult::Failed(ident.span, msg, is_last);
3411 PathResult::Module(module.unwrap_or(self.graph_root))
3414 // Resolve a local definition, potentially adjusting for closures.
3415 fn adjust_local_def(&mut self,
3420 span: Span) -> Def {
3421 let ribs = &self.ribs[ns][rib_index + 1..];
3423 // An invalid forward use of a type parameter from a previous default.
3424 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3426 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3428 assert_eq!(def, Def::Err);
3434 span_bug!(span, "unexpected {:?} in bindings", def)
3436 Def::Local(node_id) => {
3439 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3440 ForwardTyParamBanRibKind => {
3441 // Nothing to do. Continue.
3443 ClosureRibKind(function_id) => {
3446 let seen = self.freevars_seen
3448 .or_insert_with(|| NodeMap());
3449 if let Some(&index) = seen.get(&node_id) {
3450 def = Def::Upvar(node_id, index, function_id);
3453 let vec = self.freevars
3455 .or_insert_with(|| vec![]);
3456 let depth = vec.len();
3457 def = Def::Upvar(node_id, depth, function_id);
3464 seen.insert(node_id, depth);
3467 ItemRibKind | TraitOrImplItemRibKind => {
3468 // This was an attempt to access an upvar inside a
3469 // named function item. This is not allowed, so we
3472 resolve_error(self, span,
3473 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3477 ConstantItemRibKind => {
3478 // Still doesn't deal with upvars
3480 resolve_error(self, span,
3481 ResolutionError::AttemptToUseNonConstantValueInConstant);
3488 Def::TyParam(..) | Def::SelfTy(..) => {
3491 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3492 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3493 ConstantItemRibKind => {
3494 // Nothing to do. Continue.
3497 // This was an attempt to use a type parameter outside
3500 resolve_error(self, span,
3501 ResolutionError::TypeParametersFromOuterFunction(def));
3513 fn lookup_assoc_candidate<FilterFn>(&mut self,
3516 filter_fn: FilterFn)
3517 -> Option<AssocSuggestion>
3518 where FilterFn: Fn(Def) -> bool
3520 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3522 TyKind::Path(None, _) => Some(t.id),
3523 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3524 // This doesn't handle the remaining `Ty` variants as they are not
3525 // that commonly the self_type, it might be interesting to provide
3526 // support for those in future.
3531 // Fields are generally expected in the same contexts as locals.
3532 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3533 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3534 // Look for a field with the same name in the current self_type.
3535 if let Some(resolution) = self.def_map.get(&node_id) {
3536 match resolution.base_def() {
3537 Def::Struct(did) | Def::Union(did)
3538 if resolution.unresolved_segments() == 0 => {
3539 if let Some(field_names) = self.field_names.get(&did) {
3540 if field_names.iter().any(|&field_name| ident.name == field_name) {
3541 return Some(AssocSuggestion::Field);
3551 // Look for associated items in the current trait.
3552 if let Some((module, _)) = self.current_trait_ref {
3553 if let Ok(binding) =
3554 self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
3555 let def = binding.def();
3557 return Some(if self.has_self.contains(&def.def_id()) {
3558 AssocSuggestion::MethodWithSelf
3560 AssocSuggestion::AssocItem
3569 fn lookup_typo_candidate<FilterFn>(&mut self,
3572 filter_fn: FilterFn,
3575 where FilterFn: Fn(Def) -> bool
3577 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3578 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3579 if let Some(binding) = resolution.borrow().binding {
3580 if filter_fn(binding.def()) {
3581 names.push(ident.name);
3587 let mut names = Vec::new();
3588 if path.len() == 1 {
3589 // Search in lexical scope.
3590 // Walk backwards up the ribs in scope and collect candidates.
3591 for rib in self.ribs[ns].iter().rev() {
3592 // Locals and type parameters
3593 for (ident, def) in &rib.bindings {
3594 if filter_fn(*def) {
3595 names.push(ident.name);
3599 if let ModuleRibKind(module) = rib.kind {
3600 // Items from this module
3601 add_module_candidates(module, &mut names);
3603 if let ModuleKind::Block(..) = module.kind {
3604 // We can see through blocks
3606 // Items from the prelude
3607 if !module.no_implicit_prelude {
3608 names.extend(self.extern_prelude.iter().cloned());
3609 if let Some(prelude) = self.prelude {
3610 add_module_candidates(prelude, &mut names);
3617 // Add primitive types to the mix
3618 if filter_fn(Def::PrimTy(TyBool)) {
3619 for (name, _) in &self.primitive_type_table.primitive_types {
3624 // Search in module.
3625 let mod_path = &path[..path.len() - 1];
3626 if let PathResult::Module(module) = self.resolve_path(mod_path, Some(TypeNS),
3627 false, span, None) {
3628 add_module_candidates(module, &mut names);
3632 let name = path[path.len() - 1].name;
3633 // Make sure error reporting is deterministic.
3634 names.sort_by_cached_key(|name| name.as_str());
3635 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3636 Some(found) if found != name => Some(found),
3641 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3642 where F: FnOnce(&mut Resolver)
3644 if let Some(label) = label {
3645 let def = Def::Label(id);
3646 self.with_label_rib(|this| {
3647 this.label_ribs.last_mut().unwrap().bindings.insert(label.ident, def);
3655 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
3656 self.with_resolved_label(label, id, |this| this.visit_block(block));
3659 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
3660 // First, record candidate traits for this expression if it could
3661 // result in the invocation of a method call.
3663 self.record_candidate_traits_for_expr_if_necessary(expr);
3665 // Next, resolve the node.
3667 ExprKind::Path(ref qself, ref path) => {
3668 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
3669 visit::walk_expr(self, expr);
3672 ExprKind::Struct(ref path, ..) => {
3673 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
3674 visit::walk_expr(self, expr);
3677 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
3678 match self.search_label(label.ident, |rib, id| rib.bindings.get(&id).cloned()) {
3680 // Search again for close matches...
3681 // Picks the first label that is "close enough", which is not necessarily
3682 // the closest match
3683 let close_match = self.search_label(label.ident, |rib, ident| {
3684 let names = rib.bindings.iter().map(|(id, _)| &id.name);
3685 find_best_match_for_name(names, &*ident.name.as_str(), None)
3687 self.record_def(expr.id, err_path_resolution());
3690 ResolutionError::UndeclaredLabel(&label.ident.name.as_str(),
3693 Some(def @ Def::Label(_)) => {
3694 // Since this def is a label, it is never read.
3695 self.record_def(expr.id, PathResolution::new(def));
3698 span_bug!(expr.span, "label wasn't mapped to a label def!");
3702 // visit `break` argument if any
3703 visit::walk_expr(self, expr);
3706 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
3707 self.visit_expr(subexpression);
3709 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3710 let mut bindings_list = FxHashMap();
3712 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
3714 // This has to happen *after* we determine which pat_idents are variants
3715 self.check_consistent_bindings(pats);
3716 self.visit_block(if_block);
3717 self.ribs[ValueNS].pop();
3719 optional_else.as_ref().map(|expr| self.visit_expr(expr));
3722 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
3724 ExprKind::While(ref subexpression, ref block, label) => {
3725 self.with_resolved_label(label, expr.id, |this| {
3726 this.visit_expr(subexpression);
3727 this.visit_block(block);
3731 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
3732 self.with_resolved_label(label, expr.id, |this| {
3733 this.visit_expr(subexpression);
3734 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
3735 let mut bindings_list = FxHashMap();
3737 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
3739 // This has to happen *after* we determine which pat_idents are variants
3740 this.check_consistent_bindings(pats);
3741 this.visit_block(block);
3742 this.ribs[ValueNS].pop();
3746 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
3747 self.visit_expr(subexpression);
3748 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
3749 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
3751 self.resolve_labeled_block(label, expr.id, block);
3753 self.ribs[ValueNS].pop();
3756 // Equivalent to `visit::walk_expr` + passing some context to children.
3757 ExprKind::Field(ref subexpression, _) => {
3758 self.resolve_expr(subexpression, Some(expr));
3760 ExprKind::MethodCall(ref segment, ref arguments) => {
3761 let mut arguments = arguments.iter();
3762 self.resolve_expr(arguments.next().unwrap(), Some(expr));
3763 for argument in arguments {
3764 self.resolve_expr(argument, None);
3766 self.visit_path_segment(expr.span, segment);
3769 ExprKind::Repeat(ref element, ref count) => {
3770 self.visit_expr(element);
3771 self.with_constant_rib(|this| {
3772 this.visit_expr(count);
3775 ExprKind::Call(ref callee, ref arguments) => {
3776 self.resolve_expr(callee, Some(expr));
3777 for argument in arguments {
3778 self.resolve_expr(argument, None);
3781 ExprKind::Type(ref type_expr, _) => {
3782 self.current_type_ascription.push(type_expr.span);
3783 visit::walk_expr(self, expr);
3784 self.current_type_ascription.pop();
3787 visit::walk_expr(self, expr);
3792 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
3794 ExprKind::Field(_, ident) => {
3795 // FIXME(#6890): Even though you can't treat a method like a
3796 // field, we need to add any trait methods we find that match
3797 // the field name so that we can do some nice error reporting
3798 // later on in typeck.
3799 let traits = self.get_traits_containing_item(ident, ValueNS);
3800 self.trait_map.insert(expr.id, traits);
3802 ExprKind::MethodCall(ref segment, ..) => {
3803 debug!("(recording candidate traits for expr) recording traits for {}",
3805 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
3806 self.trait_map.insert(expr.id, traits);
3814 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
3815 -> Vec<TraitCandidate> {
3816 debug!("(getting traits containing item) looking for '{}'", ident.name);
3818 let mut found_traits = Vec::new();
3819 // Look for the current trait.
3820 if let Some((module, _)) = self.current_trait_ref {
3821 if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
3822 let def_id = module.def_id().unwrap();
3823 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
3827 ident.span = ident.span.modern();
3828 let mut search_module = self.current_module;
3830 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
3832 unwrap_or!(self.hygienic_lexical_parent(search_module, &mut ident.span), break);
3835 if let Some(prelude) = self.prelude {
3836 if !search_module.no_implicit_prelude {
3837 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
3844 fn get_traits_in_module_containing_item(&mut self,
3848 found_traits: &mut Vec<TraitCandidate>) {
3849 let mut traits = module.traits.borrow_mut();
3850 if traits.is_none() {
3851 let mut collected_traits = Vec::new();
3852 module.for_each_child(|name, ns, binding| {
3853 if ns != TypeNS { return }
3854 if let Def::Trait(_) = binding.def() {
3855 collected_traits.push((name, binding));
3858 *traits = Some(collected_traits.into_boxed_slice());
3861 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
3862 let module = binding.module().unwrap();
3863 let mut ident = ident;
3864 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
3867 if self.resolve_ident_in_module_unadjusted(module, ident, ns, false, false, module.span)
3869 let import_id = match binding.kind {
3870 NameBindingKind::Import { directive, .. } => {
3871 self.maybe_unused_trait_imports.insert(directive.id);
3872 self.add_to_glob_map(directive.id, trait_name);
3877 let trait_def_id = module.def_id().unwrap();
3878 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
3883 /// When name resolution fails, this method can be used to look up candidate
3884 /// entities with the expected name. It allows filtering them using the
3885 /// supplied predicate (which should be used to only accept the types of
3886 /// definitions expected e.g. traits). The lookup spans across all crates.
3888 /// NOTE: The method does not look into imports, but this is not a problem,
3889 /// since we report the definitions (thus, the de-aliased imports).
3890 fn lookup_import_candidates<FilterFn>(&mut self,
3892 namespace: Namespace,
3893 filter_fn: FilterFn)
3894 -> Vec<ImportSuggestion>
3895 where FilterFn: Fn(Def) -> bool
3897 let mut candidates = Vec::new();
3898 let mut worklist = Vec::new();
3899 let mut seen_modules = FxHashSet();
3900 worklist.push((self.graph_root, Vec::new(), false));
3902 while let Some((in_module,
3904 in_module_is_extern)) = worklist.pop() {
3905 self.populate_module_if_necessary(in_module);
3907 // We have to visit module children in deterministic order to avoid
3908 // instabilities in reported imports (#43552).
3909 in_module.for_each_child_stable(|ident, ns, name_binding| {
3910 // avoid imports entirely
3911 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
3912 // avoid non-importable candidates as well
3913 if !name_binding.is_importable() { return; }
3915 // collect results based on the filter function
3916 if ident.name == lookup_name && ns == namespace {
3917 if filter_fn(name_binding.def()) {
3919 let mut segms = path_segments.clone();
3920 segms.push(ast::PathSegment::from_ident(ident));
3922 span: name_binding.span,
3925 // the entity is accessible in the following cases:
3926 // 1. if it's defined in the same crate, it's always
3927 // accessible (since private entities can be made public)
3928 // 2. if it's defined in another crate, it's accessible
3929 // only if both the module is public and the entity is
3930 // declared as public (due to pruning, we don't explore
3931 // outside crate private modules => no need to check this)
3932 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3933 candidates.push(ImportSuggestion { path: path });
3938 // collect submodules to explore
3939 if let Some(module) = name_binding.module() {
3941 let mut path_segments = path_segments.clone();
3942 path_segments.push(ast::PathSegment::from_ident(ident));
3944 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
3945 // add the module to the lookup
3946 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
3947 if seen_modules.insert(module.def_id().unwrap()) {
3948 worklist.push((module, path_segments, is_extern));
3958 fn find_module(&mut self,
3960 -> Option<(Module<'a>, ImportSuggestion)>
3962 let mut result = None;
3963 let mut worklist = Vec::new();
3964 let mut seen_modules = FxHashSet();
3965 worklist.push((self.graph_root, Vec::new()));
3967 while let Some((in_module, path_segments)) = worklist.pop() {
3968 // abort if the module is already found
3969 if let Some(_) = result { break; }
3971 self.populate_module_if_necessary(in_module);
3973 in_module.for_each_child_stable(|ident, _, name_binding| {
3974 // abort if the module is already found or if name_binding is private external
3975 if result.is_some() || !name_binding.vis.is_visible_locally() {
3978 if let Some(module) = name_binding.module() {
3980 let mut path_segments = path_segments.clone();
3981 path_segments.push(ast::PathSegment::from_ident(ident));
3982 if module.def() == Some(module_def) {
3984 span: name_binding.span,
3985 segments: path_segments,
3987 result = Some((module, ImportSuggestion { path: path }));
3989 // add the module to the lookup
3990 if seen_modules.insert(module.def_id().unwrap()) {
3991 worklist.push((module, path_segments));
4001 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4002 if let Def::Enum(..) = enum_def {} else {
4003 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4006 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4007 self.populate_module_if_necessary(enum_module);
4009 let mut variants = Vec::new();
4010 enum_module.for_each_child_stable(|ident, _, name_binding| {
4011 if let Def::Variant(..) = name_binding.def() {
4012 let mut segms = enum_import_suggestion.path.segments.clone();
4013 segms.push(ast::PathSegment::from_ident(ident));
4014 variants.push(Path {
4015 span: name_binding.span,
4024 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4025 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4026 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4027 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4031 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4033 ast::VisibilityKind::Public => ty::Visibility::Public,
4034 ast::VisibilityKind::Crate(..) => {
4035 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4037 ast::VisibilityKind::Inherited => {
4038 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4040 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4041 // Visibilities are resolved as global by default, add starting root segment.
4042 let segments = path.make_root().iter().chain(path.segments.iter())
4043 .map(|seg| seg.ident)
4044 .collect::<Vec<_>>();
4045 let def = self.smart_resolve_path_fragment(id, None, &segments, path.span,
4046 PathSource::Visibility).base_def();
4047 if def == Def::Err {
4048 ty::Visibility::Public
4050 let vis = ty::Visibility::Restricted(def.def_id());
4051 if self.is_accessible(vis) {
4054 self.session.span_err(path.span, "visibilities can only be restricted \
4055 to ancestor modules");
4056 ty::Visibility::Public
4063 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4064 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4067 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4068 vis.is_accessible_from(module.normal_ancestor_id, self)
4071 fn report_errors(&mut self, krate: &Crate) {
4072 self.report_shadowing_errors();
4073 self.report_with_use_injections(krate);
4074 self.report_proc_macro_import(krate);
4075 let mut reported_spans = FxHashSet();
4077 for &AmbiguityError { span, name, b1, b2, lexical, legacy } in &self.ambiguity_errors {
4078 if !reported_spans.insert(span) { continue }
4079 let participle = |binding: &NameBinding| {
4080 if binding.is_import() { "imported" } else { "defined" }
4082 let msg1 = format!("`{}` could refer to the name {} here", name, participle(b1));
4083 let msg2 = format!("`{}` could also refer to the name {} here", name, participle(b2));
4084 let note = if b1.expansion == Mark::root() || !lexical && b1.is_glob_import() {
4085 format!("consider adding an explicit import of `{}` to disambiguate", name)
4086 } else if let Def::Macro(..) = b1.def() {
4087 format!("macro-expanded {} do not shadow",
4088 if b1.is_import() { "macro imports" } else { "macros" })
4090 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4091 if b1.is_import() { "imports" } else { "items" })
4094 let id = match b2.kind {
4095 NameBindingKind::Import { directive, .. } => directive.id,
4096 _ => unreachable!(),
4098 let mut span = MultiSpan::from_span(span);
4099 span.push_span_label(b1.span, msg1);
4100 span.push_span_label(b2.span, msg2);
4101 let msg = format!("`{}` is ambiguous", name);
4102 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, &msg);
4105 struct_span_err!(self.session, span, E0659, "`{}` is ambiguous", name);
4106 err.span_note(b1.span, &msg1);
4108 Def::Macro(..) if b2.span == DUMMY_SP =>
4109 err.note(&format!("`{}` is also a builtin macro", name)),
4110 _ => err.span_note(b2.span, &msg2),
4112 err.note(¬e).emit();
4116 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4117 if !reported_spans.insert(span) { continue }
4118 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4122 fn report_with_use_injections(&mut self, krate: &Crate) {
4123 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4124 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4125 if !candidates.is_empty() {
4126 show_candidates(&mut err, span, &candidates, better, found_use);
4132 fn report_shadowing_errors(&mut self) {
4133 for (ident, scope) in replace(&mut self.lexical_macro_resolutions, Vec::new()) {
4134 self.resolve_legacy_scope(scope, ident, true);
4137 let mut reported_errors = FxHashSet();
4138 for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
4139 if self.resolve_legacy_scope(&binding.parent, binding.ident, false).is_some() &&
4140 reported_errors.insert((binding.ident, binding.span)) {
4141 let msg = format!("`{}` is already in scope", binding.ident);
4142 self.session.struct_span_err(binding.span, &msg)
4143 .note("macro-expanded `macro_rules!`s may not shadow \
4144 existing macros (see RFC 1560)")
4150 fn report_conflict<'b>(&mut self,
4154 new_binding: &NameBinding<'b>,
4155 old_binding: &NameBinding<'b>) {
4156 // Error on the second of two conflicting names
4157 if old_binding.span.lo() > new_binding.span.lo() {
4158 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4161 let container = match parent.kind {
4162 ModuleKind::Def(Def::Mod(_), _) => "module",
4163 ModuleKind::Def(Def::Trait(_), _) => "trait",
4164 ModuleKind::Block(..) => "block",
4168 let old_noun = match old_binding.is_import() {
4170 false => "definition",
4173 let new_participle = match new_binding.is_import() {
4178 let (name, span) = (ident.name, self.session.codemap().def_span(new_binding.span));
4180 if let Some(s) = self.name_already_seen.get(&name) {
4186 let old_kind = match (ns, old_binding.module()) {
4187 (ValueNS, _) => "value",
4188 (MacroNS, _) => "macro",
4189 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4190 (TypeNS, Some(module)) if module.is_normal() => "module",
4191 (TypeNS, Some(module)) if module.is_trait() => "trait",
4192 (TypeNS, _) => "type",
4195 let namespace = match ns {
4201 let msg = format!("the name `{}` is defined multiple times", name);
4203 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4204 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4205 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4206 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4207 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4209 _ => match (old_binding.is_import(), new_binding.is_import()) {
4210 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4211 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4212 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4216 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4221 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4222 if old_binding.span != DUMMY_SP {
4223 err.span_label(self.session.codemap().def_span(old_binding.span),
4224 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4227 // See https://github.com/rust-lang/rust/issues/32354
4228 if old_binding.is_import() || new_binding.is_import() {
4229 let binding = if new_binding.is_import() && new_binding.span != DUMMY_SP {
4235 let cm = self.session.codemap();
4236 let rename_msg = "You can use `as` to change the binding name of the import";
4238 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4239 binding.is_renamed_extern_crate()) {
4240 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4241 format!("Other{}", name)
4243 format!("other_{}", name)
4246 err.span_suggestion(binding.span,
4248 if snippet.ends_with(';') {
4249 format!("{} as {};",
4250 &snippet[..snippet.len()-1],
4253 format!("{} as {}", snippet, suggested_name)
4256 err.span_label(binding.span, rename_msg);
4261 self.name_already_seen.insert(name, span);
4264 fn warn_legacy_self_import(&self, directive: &'a ImportDirective<'a>) {
4265 let (id, span) = (directive.id, directive.span);
4266 let msg = "`self` no longer imports values";
4267 self.session.buffer_lint(lint::builtin::LEGACY_IMPORTS, id, span, msg);
4270 fn check_proc_macro_attrs(&mut self, attrs: &[ast::Attribute]) {
4271 if self.proc_macro_enabled { return; }
4274 if attr.path.segments.len() > 1 {
4277 let ident = attr.path.segments[0].ident;
4278 let result = self.resolve_lexical_macro_path_segment(ident,
4282 if let Ok(binding) = result {
4283 if let SyntaxExtension::AttrProcMacro(..) = *binding.binding().get_macro(self) {
4284 attr::mark_known(attr);
4286 let msg = "attribute procedural macros are experimental";
4287 let feature = "proc_macro";
4289 feature_err(&self.session.parse_sess, feature,
4290 attr.span, GateIssue::Language, msg)
4291 .span_label(binding.span(), "procedural macro imported here")
4299 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4300 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4303 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4304 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4307 fn names_to_string(idents: &[Ident]) -> String {
4308 let mut result = String::new();
4309 for (i, ident) in idents.iter()
4310 .filter(|ident| ident.name != keywords::CrateRoot.name())
4313 result.push_str("::");
4315 result.push_str(&ident.name.as_str());
4320 fn path_names_to_string(path: &Path) -> String {
4321 names_to_string(&path.segments.iter()
4322 .map(|seg| seg.ident)
4323 .collect::<Vec<_>>())
4326 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4327 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4328 let variant_path = &suggestion.path;
4329 let variant_path_string = path_names_to_string(variant_path);
4331 let path_len = suggestion.path.segments.len();
4332 let enum_path = ast::Path {
4333 span: suggestion.path.span,
4334 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4336 let enum_path_string = path_names_to_string(&enum_path);
4338 (suggestion.path.span, variant_path_string, enum_path_string)
4342 /// When an entity with a given name is not available in scope, we search for
4343 /// entities with that name in all crates. This method allows outputting the
4344 /// results of this search in a programmer-friendly way
4345 fn show_candidates(err: &mut DiagnosticBuilder,
4346 // This is `None` if all placement locations are inside expansions
4348 candidates: &[ImportSuggestion],
4352 // we want consistent results across executions, but candidates are produced
4353 // by iterating through a hash map, so make sure they are ordered:
4354 let mut path_strings: Vec<_> =
4355 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4356 path_strings.sort();
4358 let better = if better { "better " } else { "" };
4359 let msg_diff = match path_strings.len() {
4360 1 => " is found in another module, you can import it",
4361 _ => "s are found in other modules, you can import them",
4363 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4365 if let Some(span) = span {
4366 for candidate in &mut path_strings {
4367 // produce an additional newline to separate the new use statement
4368 // from the directly following item.
4369 let additional_newline = if found_use {
4374 *candidate = format!("use {};\n{}", candidate, additional_newline);
4377 err.span_suggestions(span, &msg, path_strings);
4381 for candidate in path_strings {
4383 msg.push_str(&candidate);
4388 /// A somewhat inefficient routine to obtain the name of a module.
4389 fn module_to_string(module: Module) -> Option<String> {
4390 let mut names = Vec::new();
4392 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4393 if let ModuleKind::Def(_, name) = module.kind {
4394 if let Some(parent) = module.parent {
4395 names.push(Ident::with_empty_ctxt(name));
4396 collect_mod(names, parent);
4399 // danger, shouldn't be ident?
4400 names.push(Ident::from_str("<opaque>"));
4401 collect_mod(names, module.parent.unwrap());
4404 collect_mod(&mut names, module);
4406 if names.is_empty() {
4409 Some(names_to_string(&names.into_iter()
4411 .collect::<Vec<_>>()))
4414 fn err_path_resolution() -> PathResolution {
4415 PathResolution::new(Def::Err)
4418 #[derive(PartialEq,Copy, Clone)]
4419 pub enum MakeGlobMap {
4424 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }