1 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
2 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
3 html_root_url = "https://doc.rust-lang.org/nightly/")]
5 #![feature(crate_visibility_modifier)]
6 #![feature(label_break_value)]
7 #![feature(rustc_diagnostic_macros)]
8 #![feature(slice_sort_by_cached_key)]
10 #![recursion_limit="256"]
12 #![deny(rust_2018_idioms)]
14 use rustc_errors as errors;
16 pub use rustc::hir::def::{Namespace, PerNS};
18 use GenericParameters::*;
21 use rustc::hir::map::{Definitions, DefCollector};
22 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
23 use rustc::middle::cstore::CrateStore;
24 use rustc::session::Session;
26 use rustc::hir::def::*;
27 use rustc::hir::def::Namespace::*;
28 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
29 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
30 use rustc::session::config::nightly_options;
32 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
33 use rustc::{bug, span_bug};
35 use rustc_metadata::creader::CrateLoader;
36 use rustc_metadata::cstore::CStore;
38 use syntax::source_map::SourceMap;
39 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
40 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
41 use syntax::ext::base::SyntaxExtension;
42 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
43 use syntax::ext::base::MacroKind;
44 use syntax::symbol::{Symbol, keywords};
45 use syntax::util::lev_distance::find_best_match_for_name;
47 use syntax::visit::{self, FnKind, Visitor};
49 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
50 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
51 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
52 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
53 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
55 use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
57 use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
58 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
62 use std::cell::{Cell, RefCell};
63 use std::{cmp, fmt, iter, mem, ptr};
64 use std::collections::BTreeSet;
65 use std::mem::replace;
66 use rustc_data_structures::ptr_key::PtrKey;
67 use rustc_data_structures::sync::Lrc;
69 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
70 use macros::{InvocationData, LegacyBinding, ParentScope};
72 // N.B., this module needs to be declared first so diagnostics are
73 // registered before they are used.
78 mod build_reduced_graph;
81 fn is_known_tool(name: Name) -> bool {
82 ["clippy", "rustfmt"].contains(&&*name.as_str())
92 AbsolutePath(Namespace),
97 /// A free importable items suggested in case of resolution failure.
98 struct ImportSuggestion {
102 /// A field or associated item from self type suggested in case of resolution failure.
103 enum AssocSuggestion {
110 struct BindingError {
112 origin: BTreeSet<Span>,
113 target: BTreeSet<Span>,
116 struct TypoSuggestion {
119 /// The kind of the binding ("crate", "module", etc.)
122 /// An appropriate article to refer to the binding ("a", "an", etc.)
123 article: &'static str,
126 impl PartialOrd for BindingError {
127 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
128 Some(self.cmp(other))
132 impl PartialEq for BindingError {
133 fn eq(&self, other: &BindingError) -> bool {
134 self.name == other.name
138 impl Ord for BindingError {
139 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
140 self.name.cmp(&other.name)
144 enum ResolutionError<'a> {
145 /// error E0401: can't use type or const parameters from outer function
146 GenericParamsFromOuterFunction(Def),
147 /// error E0403: the name is already used for a type/const parameter in this list of
148 /// generic parameters
149 NameAlreadyUsedInParameterList(Name, &'a Span),
150 /// error E0407: method is not a member of trait
151 MethodNotMemberOfTrait(Name, &'a str),
152 /// error E0437: type is not a member of trait
153 TypeNotMemberOfTrait(Name, &'a str),
154 /// error E0438: const is not a member of trait
155 ConstNotMemberOfTrait(Name, &'a str),
156 /// error E0408: variable `{}` is not bound in all patterns
157 VariableNotBoundInPattern(&'a BindingError),
158 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
159 VariableBoundWithDifferentMode(Name, Span),
160 /// error E0415: identifier is bound more than once in this parameter list
161 IdentifierBoundMoreThanOnceInParameterList(&'a str),
162 /// error E0416: identifier is bound more than once in the same pattern
163 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
164 /// error E0426: use of undeclared label
165 UndeclaredLabel(&'a str, Option<Name>),
166 /// error E0429: `self` imports are only allowed within a { } list
167 SelfImportsOnlyAllowedWithin,
168 /// error E0430: `self` import can only appear once in the list
169 SelfImportCanOnlyAppearOnceInTheList,
170 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
171 SelfImportOnlyInImportListWithNonEmptyPrefix,
172 /// error E0433: failed to resolve
173 FailedToResolve(&'a str),
174 /// error E0434: can't capture dynamic environment in a fn item
175 CannotCaptureDynamicEnvironmentInFnItem,
176 /// error E0435: attempt to use a non-constant value in a constant
177 AttemptToUseNonConstantValueInConstant,
178 /// error E0530: X bindings cannot shadow Ys
179 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
180 /// error E0128: type parameters with a default cannot use forward declared identifiers
181 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
184 /// Combines an error with provided span and emits it
186 /// This takes the error provided, combines it with the span and any additional spans inside the
187 /// error and emits it.
188 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
190 resolution_error: ResolutionError<'a>) {
191 resolve_struct_error(resolver, span, resolution_error).emit();
194 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
196 resolution_error: ResolutionError<'a>)
197 -> DiagnosticBuilder<'sess> {
198 match resolution_error {
199 ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
200 let mut err = struct_span_err!(resolver.session,
203 "can't use generic parameters from outer function",
205 err.span_label(span, format!("use of generic parameter from outer function"));
207 let cm = resolver.session.source_map();
209 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
210 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
211 resolver.definitions.opt_span(def_id)
214 reduce_impl_span_to_impl_keyword(cm, impl_span),
215 "`Self` type implicitly declared here, by this `impl`",
218 match (maybe_trait_defid, maybe_impl_defid) {
220 err.span_label(span, "can't use `Self` here");
223 err.span_label(span, "use a type here instead");
225 (None, None) => bug!("`impl` without trait nor type?"),
229 Def::TyParam(def_id) => {
230 if let Some(span) = resolver.definitions.opt_span(def_id) {
231 err.span_label(span, "type variable from outer function");
234 Def::ConstParam(def_id) => {
235 if let Some(span) = resolver.definitions.opt_span(def_id) {
236 err.span_label(span, "const variable from outer function");
240 bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
245 // Try to retrieve the span of the function signature and generate a new message with
246 // a local type or const parameter.
247 let sugg_msg = &format!("try using a local generic parameter instead");
248 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
249 // Suggest the modification to the user
254 Applicability::MachineApplicable,
256 } else if let Some(sp) = cm.generate_fn_name_span(span) {
258 format!("try adding a local generic parameter in this method instead"));
260 err.help(&format!("try using a local generic parameter instead"));
265 ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
266 let mut err = struct_span_err!(resolver.session,
269 "the name `{}` is already used for a generic \
270 parameter in this list of generic parameters",
272 err.span_label(span, "already used");
273 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
276 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
277 let mut err = struct_span_err!(resolver.session,
280 "method `{}` is not a member of trait `{}`",
283 err.span_label(span, format!("not a member of trait `{}`", trait_));
286 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
287 let mut err = struct_span_err!(resolver.session,
290 "type `{}` is not a member of trait `{}`",
293 err.span_label(span, format!("not a member of trait `{}`", trait_));
296 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
297 let mut err = struct_span_err!(resolver.session,
300 "const `{}` is not a member of trait `{}`",
303 err.span_label(span, format!("not a member of trait `{}`", trait_));
306 ResolutionError::VariableNotBoundInPattern(binding_error) => {
307 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
308 let msp = MultiSpan::from_spans(target_sp.clone());
309 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
310 let mut err = resolver.session.struct_span_err_with_code(
313 DiagnosticId::Error("E0408".into()),
315 for sp in target_sp {
316 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
318 let origin_sp = binding_error.origin.iter().cloned();
319 for sp in origin_sp {
320 err.span_label(sp, "variable not in all patterns");
324 ResolutionError::VariableBoundWithDifferentMode(variable_name,
325 first_binding_span) => {
326 let mut err = struct_span_err!(resolver.session,
329 "variable `{}` is bound in inconsistent \
330 ways within the same match arm",
332 err.span_label(span, "bound in different ways");
333 err.span_label(first_binding_span, "first binding");
336 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
337 let mut err = struct_span_err!(resolver.session,
340 "identifier `{}` is bound more than once in this parameter list",
342 err.span_label(span, "used as parameter more than once");
345 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
346 let mut err = struct_span_err!(resolver.session,
349 "identifier `{}` is bound more than once in the same pattern",
351 err.span_label(span, "used in a pattern more than once");
354 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
355 let mut err = struct_span_err!(resolver.session,
358 "use of undeclared label `{}`",
360 if let Some(lev_candidate) = lev_candidate {
361 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
363 err.span_label(span, format!("undeclared label `{}`", name));
367 ResolutionError::SelfImportsOnlyAllowedWithin => {
368 struct_span_err!(resolver.session,
372 "`self` imports are only allowed within a { } list")
374 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
375 let mut err = struct_span_err!(resolver.session, span, E0430,
376 "`self` import can only appear once in an import list");
377 err.span_label(span, "can only appear once in an import list");
380 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
381 let mut err = struct_span_err!(resolver.session, span, E0431,
382 "`self` import can only appear in an import list with \
383 a non-empty prefix");
384 err.span_label(span, "can only appear in an import list with a non-empty prefix");
387 ResolutionError::FailedToResolve(msg) => {
388 let mut err = struct_span_err!(resolver.session, span, E0433,
389 "failed to resolve: {}", msg);
390 err.span_label(span, msg);
393 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
394 let mut err = struct_span_err!(resolver.session,
398 "can't capture dynamic environment in a fn item");
399 err.help("use the `|| { ... }` closure form instead");
402 ResolutionError::AttemptToUseNonConstantValueInConstant => {
403 let mut err = struct_span_err!(resolver.session, span, E0435,
404 "attempt to use a non-constant value in a constant");
405 err.span_label(span, "non-constant value");
408 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
409 let shadows_what = binding.descr();
410 let mut err = struct_span_err!(resolver.session, span, E0530, "{}s cannot shadow {}s",
411 what_binding, shadows_what);
412 err.span_label(span, format!("cannot be named the same as {} {}",
413 binding.article(), shadows_what));
414 let participle = if binding.is_import() { "imported" } else { "defined" };
415 let msg = format!("the {} `{}` is {} here", shadows_what, name, participle);
416 err.span_label(binding.span, msg);
419 ResolutionError::ForwardDeclaredTyParam => {
420 let mut err = struct_span_err!(resolver.session, span, E0128,
421 "type parameters with a default cannot use \
422 forward declared identifiers");
424 span, "defaulted type parameters cannot be forward declared".to_string());
430 /// Adjust the impl span so that just the `impl` keyword is taken by removing
431 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
432 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
434 /// Attention: The method used is very fragile since it essentially duplicates the work of the
435 /// parser. If you need to use this function or something similar, please consider updating the
436 /// source_map functions and this function to something more robust.
437 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
438 let impl_span = cm.span_until_char(impl_span, '<');
439 let impl_span = cm.span_until_whitespace(impl_span);
443 #[derive(Copy, Clone, Debug)]
446 binding_mode: BindingMode,
449 /// Map from the name in a pattern to its binding mode.
450 type BindingMap = FxHashMap<Ident, BindingInfo>;
452 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
463 fn descr(self) -> &'static str {
465 PatternSource::Match => "match binding",
466 PatternSource::IfLet => "if let binding",
467 PatternSource::WhileLet => "while let binding",
468 PatternSource::Let => "let binding",
469 PatternSource::For => "for binding",
470 PatternSource::FnParam => "function parameter",
475 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
476 enum AliasPossibility {
481 #[derive(Copy, Clone, Debug)]
482 enum PathSource<'a> {
483 // Type paths `Path`.
485 // Trait paths in bounds or impls.
486 Trait(AliasPossibility),
487 // Expression paths `path`, with optional parent context.
488 Expr(Option<&'a Expr>),
489 // Paths in path patterns `Path`.
491 // Paths in struct expressions and patterns `Path { .. }`.
493 // Paths in tuple struct patterns `Path(..)`.
495 // `m::A::B` in `<T as m::A>::B::C`.
496 TraitItem(Namespace),
497 // Path in `pub(path)`
501 impl<'a> PathSource<'a> {
502 fn namespace(self) -> Namespace {
504 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
505 PathSource::Visibility => TypeNS,
506 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
507 PathSource::TraitItem(ns) => ns,
511 fn global_by_default(self) -> bool {
513 PathSource::Visibility => true,
514 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
515 PathSource::Struct | PathSource::TupleStruct |
516 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
520 fn defer_to_typeck(self) -> bool {
522 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
523 PathSource::Struct | PathSource::TupleStruct => true,
524 PathSource::Trait(_) | PathSource::TraitItem(..) |
525 PathSource::Visibility => false,
529 fn descr_expected(self) -> &'static str {
531 PathSource::Type => "type",
532 PathSource::Trait(_) => "trait",
533 PathSource::Pat => "unit struct/variant or constant",
534 PathSource::Struct => "struct, variant or union type",
535 PathSource::TupleStruct => "tuple struct/variant",
536 PathSource::Visibility => "module",
537 PathSource::TraitItem(ns) => match ns {
538 TypeNS => "associated type",
539 ValueNS => "method or associated constant",
540 MacroNS => bug!("associated macro"),
542 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
543 // "function" here means "anything callable" rather than `Def::Fn`,
544 // this is not precise but usually more helpful than just "value".
545 Some(&ExprKind::Call(..)) => "function",
551 fn is_expected(self, def: Def) -> bool {
553 PathSource::Type => match def {
554 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
555 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
556 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
557 Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
560 PathSource::Trait(AliasPossibility::No) => match def {
561 Def::Trait(..) => true,
564 PathSource::Trait(AliasPossibility::Maybe) => match def {
565 Def::Trait(..) => true,
566 Def::TraitAlias(..) => true,
569 PathSource::Expr(..) => match def {
570 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
571 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
572 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
573 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
574 Def::SelfCtor(..) | Def::ConstParam(..) => true,
577 PathSource::Pat => match def {
578 Def::StructCtor(_, CtorKind::Const) |
579 Def::VariantCtor(_, CtorKind::Const) |
580 Def::Const(..) | Def::AssociatedConst(..) |
581 Def::SelfCtor(..) => true,
584 PathSource::TupleStruct => match def {
585 Def::StructCtor(_, CtorKind::Fn) |
586 Def::VariantCtor(_, CtorKind::Fn) |
587 Def::SelfCtor(..) => true,
590 PathSource::Struct => match def {
591 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
592 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
595 PathSource::TraitItem(ns) => match def {
596 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
597 Def::AssociatedTy(..) if ns == TypeNS => true,
600 PathSource::Visibility => match def {
601 Def::Mod(..) => true,
607 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
608 __diagnostic_used!(E0404);
609 __diagnostic_used!(E0405);
610 __diagnostic_used!(E0412);
611 __diagnostic_used!(E0422);
612 __diagnostic_used!(E0423);
613 __diagnostic_used!(E0425);
614 __diagnostic_used!(E0531);
615 __diagnostic_used!(E0532);
616 __diagnostic_used!(E0573);
617 __diagnostic_used!(E0574);
618 __diagnostic_used!(E0575);
619 __diagnostic_used!(E0576);
620 __diagnostic_used!(E0577);
621 __diagnostic_used!(E0578);
622 match (self, has_unexpected_resolution) {
623 (PathSource::Trait(_), true) => "E0404",
624 (PathSource::Trait(_), false) => "E0405",
625 (PathSource::Type, true) => "E0573",
626 (PathSource::Type, false) => "E0412",
627 (PathSource::Struct, true) => "E0574",
628 (PathSource::Struct, false) => "E0422",
629 (PathSource::Expr(..), true) => "E0423",
630 (PathSource::Expr(..), false) => "E0425",
631 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
632 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
633 (PathSource::TraitItem(..), true) => "E0575",
634 (PathSource::TraitItem(..), false) => "E0576",
635 (PathSource::Visibility, true) => "E0577",
636 (PathSource::Visibility, false) => "E0578",
641 // A minimal representation of a path segment. We use this in resolve because
642 // we synthesize 'path segments' which don't have the rest of an AST or HIR
644 #[derive(Clone, Copy, Debug)]
651 fn from_path(path: &Path) -> Vec<Segment> {
652 path.segments.iter().map(|s| s.into()).collect()
655 fn from_ident(ident: Ident) -> Segment {
662 fn names_to_string(segments: &[Segment]) -> String {
663 names_to_string(&segments.iter()
664 .map(|seg| seg.ident)
665 .collect::<Vec<_>>())
669 impl<'a> From<&'a ast::PathSegment> for Segment {
670 fn from(seg: &'a ast::PathSegment) -> Segment {
678 struct UsePlacementFinder {
679 target_module: NodeId,
684 impl UsePlacementFinder {
685 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
686 let mut finder = UsePlacementFinder {
691 visit::walk_crate(&mut finder, krate);
692 (finder.span, finder.found_use)
696 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
699 module: &'tcx ast::Mod,
701 _: &[ast::Attribute],
704 if self.span.is_some() {
707 if node_id != self.target_module {
708 visit::walk_mod(self, module);
711 // find a use statement
712 for item in &module.items {
714 ItemKind::Use(..) => {
715 // don't suggest placing a use before the prelude
716 // import or other generated ones
717 if item.span.ctxt().outer().expn_info().is_none() {
718 self.span = Some(item.span.shrink_to_lo());
719 self.found_use = true;
723 // don't place use before extern crate
724 ItemKind::ExternCrate(_) => {}
725 // but place them before the first other item
726 _ => if self.span.map_or(true, |span| item.span < span ) {
727 if item.span.ctxt().outer().expn_info().is_none() {
728 // don't insert between attributes and an item
729 if item.attrs.is_empty() {
730 self.span = Some(item.span.shrink_to_lo());
732 // find the first attribute on the item
733 for attr in &item.attrs {
734 if self.span.map_or(true, |span| attr.span < span) {
735 self.span = Some(attr.span.shrink_to_lo());
746 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
747 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
748 fn visit_item(&mut self, item: &'tcx Item) {
749 self.resolve_item(item);
751 fn visit_arm(&mut self, arm: &'tcx Arm) {
752 self.resolve_arm(arm);
754 fn visit_block(&mut self, block: &'tcx Block) {
755 self.resolve_block(block);
757 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
758 debug!("visit_anon_const {:?}", constant);
759 self.with_constant_rib(|this| {
760 visit::walk_anon_const(this, constant);
763 fn visit_expr(&mut self, expr: &'tcx Expr) {
764 self.resolve_expr(expr, None);
766 fn visit_local(&mut self, local: &'tcx Local) {
767 self.resolve_local(local);
769 fn visit_ty(&mut self, ty: &'tcx Ty) {
771 TyKind::Path(ref qself, ref path) => {
772 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
774 TyKind::ImplicitSelf => {
775 let self_ty = keywords::SelfUpper.ident();
776 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
777 .map_or(Def::Err, |d| d.def());
778 self.record_def(ty.id, PathResolution::new(def));
782 visit::walk_ty(self, ty);
784 fn visit_poly_trait_ref(&mut self,
785 tref: &'tcx ast::PolyTraitRef,
786 m: &'tcx ast::TraitBoundModifier) {
787 self.smart_resolve_path(tref.trait_ref.ref_id, None,
788 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
789 visit::walk_poly_trait_ref(self, tref, m);
791 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
792 let generic_params = match foreign_item.node {
793 ForeignItemKind::Fn(_, ref generics) => {
794 HasGenericParams(generics, ItemRibKind)
796 ForeignItemKind::Static(..) => NoGenericParams,
797 ForeignItemKind::Ty => NoGenericParams,
798 ForeignItemKind::Macro(..) => NoGenericParams,
800 self.with_generic_param_rib(generic_params, |this| {
801 visit::walk_foreign_item(this, foreign_item);
804 fn visit_fn(&mut self,
805 function_kind: FnKind<'tcx>,
806 declaration: &'tcx FnDecl,
810 debug!("(resolving function) entering function");
811 let (rib_kind, asyncness) = match function_kind {
812 FnKind::ItemFn(_, ref header, ..) =>
813 (ItemRibKind, header.asyncness),
814 FnKind::Method(_, ref sig, _, _) =>
815 (TraitOrImplItemRibKind, sig.header.asyncness),
816 FnKind::Closure(_) =>
817 // Async closures aren't resolved through `visit_fn`-- they're
818 // processed separately
819 (ClosureRibKind(node_id), IsAsync::NotAsync),
822 // Create a value rib for the function.
823 self.ribs[ValueNS].push(Rib::new(rib_kind));
825 // Create a label rib for the function.
826 self.label_ribs.push(Rib::new(rib_kind));
828 // Add each argument to the rib.
829 let mut bindings_list = FxHashMap::default();
830 for argument in &declaration.inputs {
831 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
833 self.visit_ty(&argument.ty);
835 debug!("(resolving function) recorded argument");
837 visit::walk_fn_ret_ty(self, &declaration.output);
839 // Resolve the function body, potentially inside the body of an async closure
840 if let IsAsync::Async { closure_id, .. } = asyncness {
841 let rib_kind = ClosureRibKind(closure_id);
842 self.ribs[ValueNS].push(Rib::new(rib_kind));
843 self.label_ribs.push(Rib::new(rib_kind));
846 match function_kind {
847 FnKind::ItemFn(.., body) |
848 FnKind::Method(.., body) => {
849 self.visit_block(body);
851 FnKind::Closure(body) => {
852 self.visit_expr(body);
856 // Leave the body of the async closure
857 if asyncness.is_async() {
858 self.label_ribs.pop();
859 self.ribs[ValueNS].pop();
862 debug!("(resolving function) leaving function");
864 self.label_ribs.pop();
865 self.ribs[ValueNS].pop();
868 fn visit_generics(&mut self, generics: &'tcx Generics) {
869 // For type parameter defaults, we have to ban access
870 // to following type parameters, as the Substs can only
871 // provide previous type parameters as they're built. We
872 // put all the parameters on the ban list and then remove
873 // them one by one as they are processed and become available.
874 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
875 let mut found_default = false;
876 default_ban_rib.bindings.extend(generics.params.iter()
877 .filter_map(|param| match param.kind {
878 GenericParamKind::Const { .. } |
879 GenericParamKind::Lifetime { .. } => None,
880 GenericParamKind::Type { ref default, .. } => {
881 found_default |= default.is_some();
883 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
890 for param in &generics.params {
892 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
893 GenericParamKind::Type { ref default, .. } => {
894 for bound in ¶m.bounds {
895 self.visit_param_bound(bound);
898 if let Some(ref ty) = default {
899 self.ribs[TypeNS].push(default_ban_rib);
901 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
904 // Allow all following defaults to refer to this type parameter.
905 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
907 GenericParamKind::Const { ref ty } => {
908 for bound in ¶m.bounds {
909 self.visit_param_bound(bound);
916 for p in &generics.where_clause.predicates {
917 self.visit_where_predicate(p);
922 #[derive(Copy, Clone)]
923 enum GenericParameters<'a, 'b> {
925 HasGenericParams(// Type parameters.
928 // The kind of the rib used for type parameters.
932 /// The rib kind controls the translation of local
933 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
934 #[derive(Copy, Clone, Debug)]
936 /// No translation needs to be applied.
939 /// We passed through a closure scope at the given node ID.
940 /// Translate upvars as appropriate.
941 ClosureRibKind(NodeId /* func id */),
943 /// We passed through an impl or trait and are now in one of its
944 /// methods or associated types. Allow references to ty params that impl or trait
945 /// binds. Disallow any other upvars (including other ty params that are
947 TraitOrImplItemRibKind,
949 /// We passed through an item scope. Disallow upvars.
952 /// We're in a constant item. Can't refer to dynamic stuff.
955 /// We passed through a module.
956 ModuleRibKind(Module<'a>),
958 /// We passed through a `macro_rules!` statement
959 MacroDefinition(DefId),
961 /// All bindings in this rib are type parameters that can't be used
962 /// from the default of a type parameter because they're not declared
963 /// before said type parameter. Also see the `visit_generics` override.
964 ForwardTyParamBanRibKind,
969 /// A rib represents a scope names can live in. Note that these appear in many places, not just
970 /// around braces. At any place where the list of accessible names (of the given namespace)
971 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
972 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
975 /// Different [rib kinds](enum.RibKind) are transparent for different names.
977 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
978 /// resolving, the name is looked up from inside out.
981 bindings: FxHashMap<Ident, Def>,
986 fn new(kind: RibKind<'a>) -> Rib<'a> {
988 bindings: Default::default(),
994 /// An intermediate resolution result.
996 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
997 /// items are visible in their whole block, while defs only from the place they are defined
999 enum LexicalScopeBinding<'a> {
1000 Item(&'a NameBinding<'a>),
1004 impl<'a> LexicalScopeBinding<'a> {
1005 fn item(self) -> Option<&'a NameBinding<'a>> {
1007 LexicalScopeBinding::Item(binding) => Some(binding),
1012 fn def(self) -> Def {
1014 LexicalScopeBinding::Item(binding) => binding.def(),
1015 LexicalScopeBinding::Def(def) => def,
1020 #[derive(Copy, Clone, Debug)]
1021 enum ModuleOrUniformRoot<'a> {
1025 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
1026 CrateRootAndExternPrelude,
1028 /// Virtual module that denotes resolution in extern prelude.
1029 /// Used for paths starting with `::` on 2018 edition.
1032 /// Virtual module that denotes resolution in current scope.
1033 /// Used only for resolving single-segment imports. The reason it exists is that import paths
1034 /// are always split into two parts, the first of which should be some kind of module.
1038 impl ModuleOrUniformRoot<'_> {
1039 fn same_def(lhs: Self, rhs: Self) -> bool {
1041 (ModuleOrUniformRoot::Module(lhs),
1042 ModuleOrUniformRoot::Module(rhs)) => lhs.def() == rhs.def(),
1043 (ModuleOrUniformRoot::CrateRootAndExternPrelude,
1044 ModuleOrUniformRoot::CrateRootAndExternPrelude) |
1045 (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) |
1046 (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
1052 #[derive(Clone, Debug)]
1053 enum PathResult<'a> {
1054 Module(ModuleOrUniformRoot<'a>),
1055 NonModule(PathResolution),
1057 Failed(Span, String, bool /* is the error from the last segment? */),
1061 /// An anonymous module, eg. just a block.
1065 /// fn f() {} // (1)
1066 /// { // This is an anonymous module
1067 /// f(); // This resolves to (2) as we are inside the block.
1068 /// fn f() {} // (2)
1070 /// f(); // Resolves to (1)
1074 /// Any module with a name.
1078 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1079 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1084 /// One node in the tree of modules.
1085 pub struct ModuleData<'a> {
1086 parent: Option<Module<'a>>,
1089 // The def id of the closest normal module (`mod`) ancestor (including this module).
1090 normal_ancestor_id: DefId,
1092 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1093 single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
1094 Option<&'a NameBinding<'a>>)>>,
1095 multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
1097 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1099 // Macro invocations that can expand into items in this module.
1100 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1102 no_implicit_prelude: bool,
1104 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1105 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1107 // Used to memoize the traits in this module for faster searches through all traits in scope.
1108 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1110 // Whether this module is populated. If not populated, any attempt to
1111 // access the children must be preceded with a
1112 // `populate_module_if_necessary` call.
1113 populated: Cell<bool>,
1115 /// Span of the module itself. Used for error reporting.
1121 type Module<'a> = &'a ModuleData<'a>;
1123 impl<'a> ModuleData<'a> {
1124 fn new(parent: Option<Module<'a>>,
1126 normal_ancestor_id: DefId,
1128 span: Span) -> Self {
1133 resolutions: Default::default(),
1134 single_segment_macro_resolutions: RefCell::new(Vec::new()),
1135 multi_segment_macro_resolutions: RefCell::new(Vec::new()),
1136 builtin_attrs: RefCell::new(Vec::new()),
1137 unresolved_invocations: Default::default(),
1138 no_implicit_prelude: false,
1139 glob_importers: RefCell::new(Vec::new()),
1140 globs: RefCell::new(Vec::new()),
1141 traits: RefCell::new(None),
1142 populated: Cell::new(normal_ancestor_id.is_local()),
1148 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1149 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1150 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1154 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1155 let resolutions = self.resolutions.borrow();
1156 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1157 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1158 for &(&(ident, ns), &resolution) in resolutions.iter() {
1159 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1163 fn def(&self) -> Option<Def> {
1165 ModuleKind::Def(def, _) => Some(def),
1170 fn def_id(&self) -> Option<DefId> {
1171 self.def().as_ref().map(Def::def_id)
1174 // `self` resolves to the first module ancestor that `is_normal`.
1175 fn is_normal(&self) -> bool {
1177 ModuleKind::Def(Def::Mod(_), _) => true,
1182 fn is_trait(&self) -> bool {
1184 ModuleKind::Def(Def::Trait(_), _) => true,
1189 fn nearest_item_scope(&'a self) -> Module<'a> {
1190 if self.is_trait() { self.parent.unwrap() } else { self }
1193 fn is_ancestor_of(&self, mut other: &Self) -> bool {
1194 while !ptr::eq(self, other) {
1195 if let Some(parent) = other.parent {
1205 impl<'a> fmt::Debug for ModuleData<'a> {
1206 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1207 write!(f, "{:?}", self.def())
1211 /// Records a possibly-private value, type, or module definition.
1212 #[derive(Clone, Debug)]
1213 pub struct NameBinding<'a> {
1214 kind: NameBindingKind<'a>,
1215 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
1218 vis: ty::Visibility,
1221 pub trait ToNameBinding<'a> {
1222 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1225 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1226 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1231 #[derive(Clone, Debug)]
1232 enum NameBindingKind<'a> {
1233 Def(Def, /* is_macro_export */ bool),
1236 binding: &'a NameBinding<'a>,
1237 directive: &'a ImportDirective<'a>,
1242 impl<'a> NameBindingKind<'a> {
1243 /// Is this a name binding of a import?
1244 fn is_import(&self) -> bool {
1246 NameBindingKind::Import { .. } => true,
1252 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
1254 struct UseError<'a> {
1255 err: DiagnosticBuilder<'a>,
1256 /// Attach `use` statements for these candidates
1257 candidates: Vec<ImportSuggestion>,
1258 /// The node id of the module to place the use statements in
1260 /// Whether the diagnostic should state that it's "better"
1264 #[derive(Clone, Copy, PartialEq, Debug)]
1265 enum AmbiguityKind {
1270 LegacyHelperVsPrelude,
1275 MoreExpandedVsOuter,
1278 impl AmbiguityKind {
1279 fn descr(self) -> &'static str {
1281 AmbiguityKind::Import =>
1282 "name vs any other name during import resolution",
1283 AmbiguityKind::AbsolutePath =>
1284 "name in the crate root vs extern crate during absolute path resolution",
1285 AmbiguityKind::BuiltinAttr =>
1286 "built-in attribute vs any other name",
1287 AmbiguityKind::DeriveHelper =>
1288 "derive helper attribute vs any other name",
1289 AmbiguityKind::LegacyHelperVsPrelude =>
1290 "legacy plugin helper attribute vs name from prelude",
1291 AmbiguityKind::LegacyVsModern =>
1292 "`macro_rules` vs non-`macro_rules` from other module",
1293 AmbiguityKind::GlobVsOuter =>
1294 "glob import vs any other name from outer scope during import/macro resolution",
1295 AmbiguityKind::GlobVsGlob =>
1296 "glob import vs glob import in the same module",
1297 AmbiguityKind::GlobVsExpanded =>
1298 "glob import vs macro-expanded name in the same \
1299 module during import/macro resolution",
1300 AmbiguityKind::MoreExpandedVsOuter =>
1301 "macro-expanded name vs less macro-expanded name \
1302 from outer scope during import/macro resolution",
1307 /// Miscellaneous bits of metadata for better ambiguity error reporting.
1308 #[derive(Clone, Copy, PartialEq)]
1309 enum AmbiguityErrorMisc {
1316 struct AmbiguityError<'a> {
1317 kind: AmbiguityKind,
1319 b1: &'a NameBinding<'a>,
1320 b2: &'a NameBinding<'a>,
1321 misc1: AmbiguityErrorMisc,
1322 misc2: AmbiguityErrorMisc,
1325 impl<'a> NameBinding<'a> {
1326 fn module(&self) -> Option<Module<'a>> {
1328 NameBindingKind::Module(module) => Some(module),
1329 NameBindingKind::Import { binding, .. } => binding.module(),
1334 fn def(&self) -> Def {
1336 NameBindingKind::Def(def, _) => def,
1337 NameBindingKind::Module(module) => module.def().unwrap(),
1338 NameBindingKind::Import { binding, .. } => binding.def(),
1342 fn is_ambiguity(&self) -> bool {
1343 self.ambiguity.is_some() || match self.kind {
1344 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
1349 // We sometimes need to treat variants as `pub` for backwards compatibility
1350 fn pseudo_vis(&self) -> ty::Visibility {
1351 if self.is_variant() && self.def().def_id().is_local() {
1352 ty::Visibility::Public
1358 fn is_variant(&self) -> bool {
1360 NameBindingKind::Def(Def::Variant(..), _) |
1361 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1366 fn is_extern_crate(&self) -> bool {
1368 NameBindingKind::Import {
1369 directive: &ImportDirective {
1370 subclass: ImportDirectiveSubclass::ExternCrate { .. }, ..
1373 NameBindingKind::Module(
1374 &ModuleData { kind: ModuleKind::Def(Def::Mod(def_id), _), .. }
1375 ) => def_id.index == CRATE_DEF_INDEX,
1380 fn is_import(&self) -> bool {
1382 NameBindingKind::Import { .. } => true,
1387 fn is_glob_import(&self) -> bool {
1389 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1394 fn is_importable(&self) -> bool {
1396 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1401 fn is_macro_def(&self) -> bool {
1403 NameBindingKind::Def(Def::Macro(..), _) => true,
1408 fn macro_kind(&self) -> Option<MacroKind> {
1410 Def::Macro(_, kind) => Some(kind),
1411 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1416 fn descr(&self) -> &'static str {
1417 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1420 fn article(&self) -> &'static str {
1421 if self.is_extern_crate() { "an" } else { self.def().article() }
1424 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1425 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1426 // Then this function returns `true` if `self` may emerge from a macro *after* that
1427 // in some later round and screw up our previously found resolution.
1428 // See more detailed explanation in
1429 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1430 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
1431 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1432 // Expansions are partially ordered, so "may appear after" is an inversion of
1433 // "certainly appears before or simultaneously" and includes unordered cases.
1434 let self_parent_expansion = self.expansion;
1435 let other_parent_expansion = binding.expansion;
1436 let certainly_before_other_or_simultaneously =
1437 other_parent_expansion.is_descendant_of(self_parent_expansion);
1438 let certainly_before_invoc_or_simultaneously =
1439 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1440 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1444 /// Interns the names of the primitive types.
1446 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1447 /// special handling, since they have no place of origin.
1449 struct PrimitiveTypeTable {
1450 primitive_types: FxHashMap<Name, PrimTy>,
1453 impl PrimitiveTypeTable {
1454 fn new() -> PrimitiveTypeTable {
1455 let mut table = PrimitiveTypeTable::default();
1457 table.intern("bool", Bool);
1458 table.intern("char", Char);
1459 table.intern("f32", Float(FloatTy::F32));
1460 table.intern("f64", Float(FloatTy::F64));
1461 table.intern("isize", Int(IntTy::Isize));
1462 table.intern("i8", Int(IntTy::I8));
1463 table.intern("i16", Int(IntTy::I16));
1464 table.intern("i32", Int(IntTy::I32));
1465 table.intern("i64", Int(IntTy::I64));
1466 table.intern("i128", Int(IntTy::I128));
1467 table.intern("str", Str);
1468 table.intern("usize", Uint(UintTy::Usize));
1469 table.intern("u8", Uint(UintTy::U8));
1470 table.intern("u16", Uint(UintTy::U16));
1471 table.intern("u32", Uint(UintTy::U32));
1472 table.intern("u64", Uint(UintTy::U64));
1473 table.intern("u128", Uint(UintTy::U128));
1477 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1478 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1482 #[derive(Debug, Default, Clone)]
1483 pub struct ExternPreludeEntry<'a> {
1484 extern_crate_item: Option<&'a NameBinding<'a>>,
1485 pub introduced_by_item: bool,
1488 /// The main resolver class.
1490 /// This is the visitor that walks the whole crate.
1491 pub struct Resolver<'a> {
1492 session: &'a Session,
1495 pub definitions: Definitions,
1497 graph_root: Module<'a>,
1499 prelude: Option<Module<'a>>,
1500 pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
1502 /// n.b. This is used only for better diagnostics, not name resolution itself.
1503 has_self: FxHashSet<DefId>,
1505 /// Names of fields of an item `DefId` accessible with dot syntax.
1506 /// Used for hints during error reporting.
1507 field_names: FxHashMap<DefId, Vec<Name>>,
1509 /// All imports known to succeed or fail.
1510 determined_imports: Vec<&'a ImportDirective<'a>>,
1512 /// All non-determined imports.
1513 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1515 /// The module that represents the current item scope.
1516 current_module: Module<'a>,
1518 /// The current set of local scopes for types and values.
1519 /// FIXME #4948: Reuse ribs to avoid allocation.
1520 ribs: PerNS<Vec<Rib<'a>>>,
1522 /// The current set of local scopes, for labels.
1523 label_ribs: Vec<Rib<'a>>,
1525 /// The trait that the current context can refer to.
1526 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1528 /// The current self type if inside an impl (used for better errors).
1529 current_self_type: Option<Ty>,
1531 /// The current self item if inside an ADT (used for better errors).
1532 current_self_item: Option<NodeId>,
1534 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
1535 /// We are resolving a last import segment during import validation.
1536 last_import_segment: bool,
1537 /// This binding should be ignored during in-module resolution, so that we don't get
1538 /// "self-confirming" import resolutions during import validation.
1539 blacklisted_binding: Option<&'a NameBinding<'a>>,
1541 /// The idents for the primitive types.
1542 primitive_type_table: PrimitiveTypeTable,
1545 import_map: ImportMap,
1546 pub freevars: FreevarMap,
1547 freevars_seen: NodeMap<NodeMap<usize>>,
1548 pub export_map: ExportMap,
1549 pub trait_map: TraitMap,
1551 /// A map from nodes to anonymous modules.
1552 /// Anonymous modules are pseudo-modules that are implicitly created around items
1553 /// contained within blocks.
1555 /// For example, if we have this:
1563 /// There will be an anonymous module created around `g` with the ID of the
1564 /// entry block for `f`.
1565 block_map: NodeMap<Module<'a>>,
1566 module_map: FxHashMap<DefId, Module<'a>>,
1567 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1568 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
1570 /// Maps glob imports to the names of items actually imported.
1571 pub glob_map: GlobMap,
1573 used_imports: FxHashSet<(NodeId, Namespace)>,
1574 pub maybe_unused_trait_imports: NodeSet,
1575 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1577 /// A list of labels as of yet unused. Labels will be removed from this map when
1578 /// they are used (in a `break` or `continue` statement)
1579 pub unused_labels: FxHashMap<NodeId, Span>,
1581 /// privacy errors are delayed until the end in order to deduplicate them
1582 privacy_errors: Vec<PrivacyError<'a>>,
1583 /// ambiguity errors are delayed for deduplication
1584 ambiguity_errors: Vec<AmbiguityError<'a>>,
1585 /// `use` injections are delayed for better placement and deduplication
1586 use_injections: Vec<UseError<'a>>,
1587 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1588 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1590 arenas: &'a ResolverArenas<'a>,
1591 dummy_binding: &'a NameBinding<'a>,
1593 crate_loader: &'a mut CrateLoader<'a>,
1594 macro_names: FxHashSet<Ident>,
1595 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1596 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1597 pub all_macros: FxHashMap<Name, Def>,
1598 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1599 macro_defs: FxHashMap<Mark, DefId>,
1600 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1602 /// List of crate local macros that we need to warn about as being unused.
1603 /// Right now this only includes macro_rules! macros, and macros 2.0.
1604 unused_macros: FxHashSet<DefId>,
1606 /// Maps the `Mark` of an expansion to its containing module or block.
1607 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1609 /// Avoid duplicated errors for "name already defined".
1610 name_already_seen: FxHashMap<Name, Span>,
1612 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1614 /// This table maps struct IDs into struct constructor IDs,
1615 /// it's not used during normal resolution, only for better error reporting.
1616 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1618 /// Only used for better errors on `fn(): fn()`
1619 current_type_ascription: Vec<Span>,
1621 injected_crate: Option<Module<'a>>,
1624 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1626 pub struct ResolverArenas<'a> {
1627 modules: arena::TypedArena<ModuleData<'a>>,
1628 local_modules: RefCell<Vec<Module<'a>>>,
1629 name_bindings: arena::TypedArena<NameBinding<'a>>,
1630 import_directives: arena::TypedArena<ImportDirective<'a>>,
1631 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1632 invocation_data: arena::TypedArena<InvocationData<'a>>,
1633 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1636 impl<'a> ResolverArenas<'a> {
1637 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1638 let module = self.modules.alloc(module);
1639 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1640 self.local_modules.borrow_mut().push(module);
1644 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1645 self.local_modules.borrow()
1647 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1648 self.name_bindings.alloc(name_binding)
1650 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1651 -> &'a ImportDirective<'_> {
1652 self.import_directives.alloc(import_directive)
1654 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1655 self.name_resolutions.alloc(Default::default())
1657 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1658 -> &'a InvocationData<'a> {
1659 self.invocation_data.alloc(expansion_data)
1661 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1662 self.legacy_bindings.alloc(binding)
1666 impl<'a, 'b: 'a> ty::DefIdTree for &'a Resolver<'b> {
1667 fn parent(self, id: DefId) -> Option<DefId> {
1669 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1670 _ => self.cstore.def_key(id).parent,
1671 }.map(|index| DefId { index, ..id })
1675 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1676 /// the resolver is no longer needed as all the relevant information is inline.
1677 impl<'a> hir::lowering::Resolver for Resolver<'a> {
1678 fn resolve_hir_path(
1683 self.resolve_hir_path_cb(path, is_value,
1684 |resolver, span, error| resolve_error(resolver, span, error))
1687 fn resolve_str_path(
1690 crate_root: Option<&str>,
1691 components: &[&str],
1694 let segments = iter::once(keywords::PathRoot.ident())
1696 crate_root.into_iter()
1697 .chain(components.iter().cloned())
1698 .map(Ident::from_str)
1699 ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
1702 let path = ast::Path {
1707 self.resolve_hir_path(&path, is_value)
1710 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1711 self.def_map.get(&id).cloned()
1714 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1715 self.import_map.get(&id).cloned().unwrap_or_default()
1718 fn definitions(&mut self) -> &mut Definitions {
1719 &mut self.definitions
1723 impl<'a> Resolver<'a> {
1724 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1725 /// isn't something that can be returned because it can't be made to live that long,
1726 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1727 /// just that an error occurred.
1728 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1729 -> Result<hir::Path, ()> {
1731 let mut errored = false;
1733 let path = if path_str.starts_with("::") {
1736 segments: iter::once(keywords::PathRoot.ident())
1738 path_str.split("::").skip(1).map(Ident::from_str)
1740 .map(|i| self.new_ast_path_segment(i))
1748 .map(Ident::from_str)
1749 .map(|i| self.new_ast_path_segment(i))
1753 let path = self.resolve_hir_path_cb(&path, is_value, |_, _, _| errored = true);
1754 if errored || path.def == Def::Err {
1761 /// resolve_hir_path, but takes a callback in case there was an error
1762 fn resolve_hir_path_cb<F>(
1768 where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
1770 let namespace = if is_value { ValueNS } else { TypeNS };
1771 let span = path.span;
1772 let segments = &path.segments;
1773 let path = Segment::from_path(&path);
1774 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1775 let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
1776 span, CrateLint::No) {
1777 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1778 module.def().unwrap(),
1779 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1780 path_res.base_def(),
1781 PathResult::NonModule(..) => {
1782 let msg = "type-relative paths are not supported in this context";
1783 error_callback(self, span, ResolutionError::FailedToResolve(msg));
1786 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1787 PathResult::Failed(span, msg, _) => {
1788 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1793 let segments: Vec<_> = segments.iter().map(|seg| {
1794 let mut hir_seg = hir::PathSegment::from_ident(seg.ident);
1795 hir_seg.def = Some(self.def_map.get(&seg.id).map_or(Def::Err, |p| p.base_def()));
1801 segments: segments.into(),
1805 fn new_ast_path_segment(&self, ident: Ident) -> ast::PathSegment {
1806 let mut seg = ast::PathSegment::from_ident(ident);
1807 seg.id = self.session.next_node_id();
1812 impl<'a> Resolver<'a> {
1813 pub fn new(session: &'a Session,
1817 crate_loader: &'a mut CrateLoader<'a>,
1818 arenas: &'a ResolverArenas<'a>)
1820 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1821 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1822 let graph_root = arenas.alloc_module(ModuleData {
1823 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1824 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1826 let mut module_map = FxHashMap::default();
1827 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1829 let mut definitions = Definitions::new();
1830 DefCollector::new(&mut definitions, Mark::root())
1831 .collect_root(crate_name, session.local_crate_disambiguator());
1833 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
1834 session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
1837 if !attr::contains_name(&krate.attrs, "no_core") {
1838 extern_prelude.insert(Ident::from_str("core"), Default::default());
1839 if !attr::contains_name(&krate.attrs, "no_std") {
1840 extern_prelude.insert(Ident::from_str("std"), Default::default());
1841 if session.rust_2018() {
1842 extern_prelude.insert(Ident::from_str("meta"), Default::default());
1847 let mut invocations = FxHashMap::default();
1848 invocations.insert(Mark::root(),
1849 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1851 let mut macro_defs = FxHashMap::default();
1852 macro_defs.insert(Mark::root(), root_def_id);
1861 // The outermost module has def ID 0; this is not reflected in the
1867 has_self: FxHashSet::default(),
1868 field_names: FxHashMap::default(),
1870 determined_imports: Vec::new(),
1871 indeterminate_imports: Vec::new(),
1873 current_module: graph_root,
1875 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1876 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1877 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1879 label_ribs: Vec::new(),
1881 current_trait_ref: None,
1882 current_self_type: None,
1883 current_self_item: None,
1884 last_import_segment: false,
1885 blacklisted_binding: None,
1887 primitive_type_table: PrimitiveTypeTable::new(),
1889 def_map: Default::default(),
1890 import_map: Default::default(),
1891 freevars: Default::default(),
1892 freevars_seen: Default::default(),
1893 export_map: FxHashMap::default(),
1894 trait_map: Default::default(),
1896 block_map: Default::default(),
1897 extern_module_map: FxHashMap::default(),
1898 binding_parent_modules: FxHashMap::default(),
1900 glob_map: Default::default(),
1902 used_imports: FxHashSet::default(),
1903 maybe_unused_trait_imports: Default::default(),
1904 maybe_unused_extern_crates: Vec::new(),
1906 unused_labels: FxHashMap::default(),
1908 privacy_errors: Vec::new(),
1909 ambiguity_errors: Vec::new(),
1910 use_injections: Vec::new(),
1911 macro_expanded_macro_export_errors: BTreeSet::new(),
1914 dummy_binding: arenas.alloc_name_binding(NameBinding {
1915 kind: NameBindingKind::Def(Def::Err, false),
1917 expansion: Mark::root(),
1919 vis: ty::Visibility::Public,
1923 macro_names: FxHashSet::default(),
1924 builtin_macros: FxHashMap::default(),
1925 macro_use_prelude: FxHashMap::default(),
1926 all_macros: FxHashMap::default(),
1927 macro_map: FxHashMap::default(),
1930 local_macro_def_scopes: FxHashMap::default(),
1931 name_already_seen: FxHashMap::default(),
1932 potentially_unused_imports: Vec::new(),
1933 struct_constructors: Default::default(),
1934 unused_macros: FxHashSet::default(),
1935 current_type_ascription: Vec::new(),
1936 injected_crate: None,
1940 pub fn arenas() -> ResolverArenas<'a> {
1944 /// Runs the function on each namespace.
1945 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1951 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1953 match self.macro_defs.get(&ctxt.outer()) {
1954 Some(&def_id) => return def_id,
1955 None => ctxt.remove_mark(),
1960 /// Entry point to crate resolution.
1961 pub fn resolve_crate(&mut self, krate: &Crate) {
1962 ImportResolver { resolver: self }.finalize_imports();
1963 self.current_module = self.graph_root;
1964 self.finalize_current_module_macro_resolutions();
1966 visit::walk_crate(self, krate);
1968 check_unused::check_crate(self, krate);
1969 self.report_errors(krate);
1970 self.crate_loader.postprocess(krate);
1977 normal_ancestor_id: DefId,
1981 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1982 self.arenas.alloc_module(module)
1985 fn record_use(&mut self, ident: Ident, ns: Namespace,
1986 used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
1987 if let Some((b2, kind)) = used_binding.ambiguity {
1988 self.ambiguity_errors.push(AmbiguityError {
1989 kind, ident, b1: used_binding, b2,
1990 misc1: AmbiguityErrorMisc::None,
1991 misc2: AmbiguityErrorMisc::None,
1994 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1995 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1996 // but not introduce it, as used if they are accessed from lexical scope.
1997 if is_lexical_scope {
1998 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1999 if let Some(crate_item) = entry.extern_crate_item {
2000 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
2007 directive.used.set(true);
2008 self.used_imports.insert((directive.id, ns));
2009 self.add_to_glob_map(&directive, ident);
2010 self.record_use(ident, ns, binding, false);
2015 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
2016 if directive.is_glob() {
2017 self.glob_map.entry(directive.id).or_default().insert(ident.name);
2021 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
2022 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
2023 /// `ident` in the first scope that defines it (or None if no scopes define it).
2025 /// A block's items are above its local variables in the scope hierarchy, regardless of where
2026 /// the items are defined in the block. For example,
2029 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
2032 /// g(); // This resolves to the local variable `g` since it shadows the item.
2036 /// Invariant: This must only be called during main resolution, not during
2037 /// import resolution.
2038 fn resolve_ident_in_lexical_scope(&mut self,
2041 record_used_id: Option<NodeId>,
2043 -> Option<LexicalScopeBinding<'a>> {
2044 assert!(ns == TypeNS || ns == ValueNS);
2045 if ident.name == keywords::Invalid.name() {
2046 return Some(LexicalScopeBinding::Def(Def::Err));
2048 ident.span = if ident.name == keywords::SelfUpper.name() {
2049 // FIXME(jseyfried) improve `Self` hygiene
2050 ident.span.with_ctxt(SyntaxContext::empty())
2051 } else if ns == TypeNS {
2054 ident.span.modern_and_legacy()
2057 // Walk backwards up the ribs in scope.
2058 let record_used = record_used_id.is_some();
2059 let mut module = self.graph_root;
2060 for i in (0 .. self.ribs[ns].len()).rev() {
2061 debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
2062 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
2063 // The ident resolves to a type parameter or local variable.
2064 return Some(LexicalScopeBinding::Def(
2065 self.adjust_local_def(ns, i, def, record_used, path_span)
2069 module = match self.ribs[ns][i].kind {
2070 ModuleRibKind(module) => module,
2071 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2072 // If an invocation of this macro created `ident`, give up on `ident`
2073 // and switch to `ident`'s source from the macro definition.
2074 ident.span.remove_mark();
2080 let item = self.resolve_ident_in_module_unadjusted(
2081 ModuleOrUniformRoot::Module(module),
2087 if let Ok(binding) = item {
2088 // The ident resolves to an item.
2089 return Some(LexicalScopeBinding::Item(binding));
2093 ModuleKind::Block(..) => {}, // We can see through blocks
2098 ident.span = ident.span.modern();
2099 let mut poisoned = None;
2101 let opt_module = if let Some(node_id) = record_used_id {
2102 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
2103 node_id, &mut poisoned)
2105 self.hygienic_lexical_parent(module, &mut ident.span)
2107 module = unwrap_or!(opt_module, break);
2108 let orig_current_module = self.current_module;
2109 self.current_module = module; // Lexical resolutions can never be a privacy error.
2110 let result = self.resolve_ident_in_module_unadjusted(
2111 ModuleOrUniformRoot::Module(module),
2117 self.current_module = orig_current_module;
2121 if let Some(node_id) = poisoned {
2122 self.session.buffer_lint_with_diagnostic(
2123 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
2124 node_id, ident.span,
2125 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
2126 lint::builtin::BuiltinLintDiagnostics::
2127 ProcMacroDeriveResolutionFallback(ident.span),
2130 return Some(LexicalScopeBinding::Item(binding))
2132 Err(Determined) => continue,
2133 Err(Undetermined) =>
2134 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
2138 if !module.no_implicit_prelude {
2140 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
2141 return Some(LexicalScopeBinding::Item(binding));
2144 if ns == TypeNS && is_known_tool(ident.name) {
2145 let binding = (Def::ToolMod, ty::Visibility::Public,
2146 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
2147 return Some(LexicalScopeBinding::Item(binding));
2149 if let Some(prelude) = self.prelude {
2150 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
2151 ModuleOrUniformRoot::Module(prelude),
2157 return Some(LexicalScopeBinding::Item(binding));
2165 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
2166 -> Option<Module<'a>> {
2167 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2168 return Some(self.macro_def_scope(span.remove_mark()));
2171 if let ModuleKind::Block(..) = module.kind {
2172 return Some(module.parent.unwrap());
2178 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2179 span: &mut Span, node_id: NodeId,
2180 poisoned: &mut Option<NodeId>)
2181 -> Option<Module<'a>> {
2182 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2186 // We need to support the next case under a deprecation warning
2189 // ---- begin: this comes from a proc macro derive
2190 // mod implementation_details {
2191 // // Note that `MyStruct` is not in scope here.
2192 // impl SomeTrait for MyStruct { ... }
2196 // So we have to fall back to the module's parent during lexical resolution in this case.
2197 if let Some(parent) = module.parent {
2198 // Inner module is inside the macro, parent module is outside of the macro.
2199 if module.expansion != parent.expansion &&
2200 module.expansion.is_descendant_of(parent.expansion) {
2201 // The macro is a proc macro derive
2202 if module.expansion.looks_like_proc_macro_derive() {
2203 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2204 *poisoned = Some(node_id);
2205 return module.parent;
2214 fn resolve_ident_in_module(
2216 module: ModuleOrUniformRoot<'a>,
2219 parent_scope: Option<&ParentScope<'a>>,
2222 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2223 self.resolve_ident_in_module_ext(
2224 module, ident, ns, parent_scope, record_used, path_span
2225 ).map_err(|(determinacy, _)| determinacy)
2228 fn resolve_ident_in_module_ext(
2230 module: ModuleOrUniformRoot<'a>,
2233 parent_scope: Option<&ParentScope<'a>>,
2236 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2237 let orig_current_module = self.current_module;
2239 ModuleOrUniformRoot::Module(module) => {
2240 ident.span = ident.span.modern();
2241 if let Some(def) = ident.span.adjust(module.expansion) {
2242 self.current_module = self.macro_def_scope(def);
2245 ModuleOrUniformRoot::ExternPrelude => {
2246 ident.span = ident.span.modern();
2247 ident.span.adjust(Mark::root());
2249 ModuleOrUniformRoot::CrateRootAndExternPrelude |
2250 ModuleOrUniformRoot::CurrentScope => {
2254 let result = self.resolve_ident_in_module_unadjusted_ext(
2255 module, ident, ns, parent_scope, false, record_used, path_span,
2257 self.current_module = orig_current_module;
2261 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2262 let mut ctxt = ident.span.ctxt();
2263 let mark = if ident.name == keywords::DollarCrate.name() {
2264 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2265 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2266 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2267 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2268 // definitions actually produced by `macro` and `macro` definitions produced by
2269 // `macro_rules!`, but at least such configurations are not stable yet.
2270 ctxt = ctxt.modern_and_legacy();
2271 let mut iter = ctxt.marks().into_iter().rev().peekable();
2272 let mut result = None;
2273 // Find the last modern mark from the end if it exists.
2274 while let Some(&(mark, transparency)) = iter.peek() {
2275 if transparency == Transparency::Opaque {
2276 result = Some(mark);
2282 // Then find the last legacy mark from the end if it exists.
2283 for (mark, transparency) in iter {
2284 if transparency == Transparency::SemiTransparent {
2285 result = Some(mark);
2292 ctxt = ctxt.modern();
2293 ctxt.adjust(Mark::root())
2295 let module = match mark {
2296 Some(def) => self.macro_def_scope(def),
2297 None => return self.graph_root,
2299 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2302 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2303 let mut module = self.get_module(module.normal_ancestor_id);
2304 while module.span.ctxt().modern() != *ctxt {
2305 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2306 module = self.get_module(parent.normal_ancestor_id);
2313 // We maintain a list of value ribs and type ribs.
2315 // Simultaneously, we keep track of the current position in the module
2316 // graph in the `current_module` pointer. When we go to resolve a name in
2317 // the value or type namespaces, we first look through all the ribs and
2318 // then query the module graph. When we resolve a name in the module
2319 // namespace, we can skip all the ribs (since nested modules are not
2320 // allowed within blocks in Rust) and jump straight to the current module
2323 // Named implementations are handled separately. When we find a method
2324 // call, we consult the module node to find all of the implementations in
2325 // scope. This information is lazily cached in the module node. We then
2326 // generate a fake "implementation scope" containing all the
2327 // implementations thus found, for compatibility with old resolve pass.
2329 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2330 where F: FnOnce(&mut Resolver<'_>) -> T
2332 let id = self.definitions.local_def_id(id);
2333 let module = self.module_map.get(&id).cloned(); // clones a reference
2334 if let Some(module) = module {
2335 // Move down in the graph.
2336 let orig_module = replace(&mut self.current_module, module);
2337 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2338 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2340 self.finalize_current_module_macro_resolutions();
2343 self.current_module = orig_module;
2344 self.ribs[ValueNS].pop();
2345 self.ribs[TypeNS].pop();
2352 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2353 /// is returned by the given predicate function
2355 /// Stops after meeting a closure.
2356 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2357 where P: Fn(&Rib<'_>, Ident) -> Option<R>
2359 for rib in self.label_ribs.iter().rev() {
2362 // If an invocation of this macro created `ident`, give up on `ident`
2363 // and switch to `ident`'s source from the macro definition.
2364 MacroDefinition(def) => {
2365 if def == self.macro_def(ident.span.ctxt()) {
2366 ident.span.remove_mark();
2370 // Do not resolve labels across function boundary
2374 let r = pred(rib, ident);
2382 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2383 debug!("resolve_adt");
2384 self.with_current_self_item(item, |this| {
2385 this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2386 let item_def_id = this.definitions.local_def_id(item.id);
2387 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2388 visit::walk_item(this, item);
2394 fn future_proof_import(&mut self, use_tree: &ast::UseTree) {
2395 let segments = &use_tree.prefix.segments;
2396 if !segments.is_empty() {
2397 let ident = segments[0].ident;
2398 if ident.is_path_segment_keyword() || ident.span.rust_2015() {
2402 let nss = match use_tree.kind {
2403 ast::UseTreeKind::Simple(..) if segments.len() == 1 => &[TypeNS, ValueNS][..],
2406 let report_error = |this: &Self, ns| {
2407 let what = if ns == TypeNS { "type parameters" } else { "local variables" };
2408 this.session.span_err(ident.span, &format!("imports cannot refer to {}", what));
2412 match self.resolve_ident_in_lexical_scope(ident, ns, None, use_tree.prefix.span) {
2413 Some(LexicalScopeBinding::Def(..)) => {
2414 report_error(self, ns);
2416 Some(LexicalScopeBinding::Item(binding)) => {
2417 let orig_blacklisted_binding =
2418 mem::replace(&mut self.blacklisted_binding, Some(binding));
2419 if let Some(LexicalScopeBinding::Def(..)) =
2420 self.resolve_ident_in_lexical_scope(ident, ns, None,
2421 use_tree.prefix.span) {
2422 report_error(self, ns);
2424 self.blacklisted_binding = orig_blacklisted_binding;
2429 } else if let ast::UseTreeKind::Nested(use_trees) = &use_tree.kind {
2430 for (use_tree, _) in use_trees {
2431 self.future_proof_import(use_tree);
2436 fn resolve_item(&mut self, item: &Item) {
2437 let name = item.ident.name;
2438 debug!("(resolving item) resolving {} ({:?})", name, item.node);
2441 ItemKind::Ty(_, ref generics) |
2442 ItemKind::Fn(_, _, ref generics, _) |
2443 ItemKind::Existential(_, ref generics) => {
2444 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
2445 |this| visit::walk_item(this, item));
2448 ItemKind::Enum(_, ref generics) |
2449 ItemKind::Struct(_, ref generics) |
2450 ItemKind::Union(_, ref generics) => {
2451 self.resolve_adt(item, generics);
2454 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2455 self.resolve_implementation(generics,
2461 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2462 // Create a new rib for the trait-wide type parameters.
2463 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2464 let local_def_id = this.definitions.local_def_id(item.id);
2465 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2466 this.visit_generics(generics);
2467 walk_list!(this, visit_param_bound, bounds);
2469 for trait_item in trait_items {
2470 let generic_params = HasGenericParams(&trait_item.generics,
2471 TraitOrImplItemRibKind);
2472 this.with_generic_param_rib(generic_params, |this| {
2473 match trait_item.node {
2474 TraitItemKind::Const(ref ty, ref default) => {
2477 // Only impose the restrictions of
2478 // ConstRibKind for an actual constant
2479 // expression in a provided default.
2480 if let Some(ref expr) = *default{
2481 this.with_constant_rib(|this| {
2482 this.visit_expr(expr);
2486 TraitItemKind::Method(_, _) => {
2487 visit::walk_trait_item(this, trait_item)
2489 TraitItemKind::Type(..) => {
2490 visit::walk_trait_item(this, trait_item)
2492 TraitItemKind::Macro(_) => {
2493 panic!("unexpanded macro in resolve!")
2502 ItemKind::TraitAlias(ref generics, ref bounds) => {
2503 // Create a new rib for the trait-wide type parameters.
2504 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2505 let local_def_id = this.definitions.local_def_id(item.id);
2506 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2507 this.visit_generics(generics);
2508 walk_list!(this, visit_param_bound, bounds);
2513 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2514 self.with_scope(item.id, |this| {
2515 visit::walk_item(this, item);
2519 ItemKind::Static(ref ty, _, ref expr) |
2520 ItemKind::Const(ref ty, ref expr) => {
2521 debug!("resolve_item ItemKind::Const");
2522 self.with_item_rib(|this| {
2524 this.with_constant_rib(|this| {
2525 this.visit_expr(expr);
2530 ItemKind::Use(ref use_tree) => {
2531 self.future_proof_import(use_tree);
2534 ItemKind::ExternCrate(..) |
2535 ItemKind::MacroDef(..) | ItemKind::GlobalAsm(..) => {
2536 // do nothing, these are just around to be encoded
2539 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2543 fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
2544 where F: FnOnce(&mut Resolver<'_>)
2546 debug!("with_generic_param_rib");
2547 match generic_params {
2548 HasGenericParams(generics, rib_kind) => {
2549 let mut function_type_rib = Rib::new(rib_kind);
2550 let mut function_value_rib = Rib::new(rib_kind);
2551 let mut seen_bindings = FxHashMap::default();
2552 for param in &generics.params {
2554 GenericParamKind::Lifetime { .. } => {}
2555 GenericParamKind::Type { .. } => {
2556 let ident = param.ident.modern();
2557 debug!("with_generic_param_rib: {}", param.id);
2559 if seen_bindings.contains_key(&ident) {
2560 let span = seen_bindings.get(&ident).unwrap();
2561 let err = ResolutionError::NameAlreadyUsedInParameterList(
2565 resolve_error(self, param.ident.span, err);
2567 seen_bindings.entry(ident).or_insert(param.ident.span);
2569 // Plain insert (no renaming).
2570 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2571 function_type_rib.bindings.insert(ident, def);
2572 self.record_def(param.id, PathResolution::new(def));
2574 GenericParamKind::Const { .. } => {
2575 let ident = param.ident.modern();
2576 debug!("with_generic_param_rib: {}", param.id);
2578 if seen_bindings.contains_key(&ident) {
2579 let span = seen_bindings.get(&ident).unwrap();
2580 let err = ResolutionError::NameAlreadyUsedInParameterList(
2584 resolve_error(self, param.ident.span, err);
2586 seen_bindings.entry(ident).or_insert(param.ident.span);
2588 let def = Def::ConstParam(self.definitions.local_def_id(param.id));
2589 function_value_rib.bindings.insert(ident, def);
2590 self.record_def(param.id, PathResolution::new(def));
2594 self.ribs[ValueNS].push(function_value_rib);
2595 self.ribs[TypeNS].push(function_type_rib);
2598 NoGenericParams => {
2605 if let HasGenericParams(..) = generic_params {
2606 self.ribs[TypeNS].pop();
2607 self.ribs[ValueNS].pop();
2611 fn with_label_rib<F>(&mut self, f: F)
2612 where F: FnOnce(&mut Resolver<'_>)
2614 self.label_ribs.push(Rib::new(NormalRibKind));
2616 self.label_ribs.pop();
2619 fn with_item_rib<F>(&mut self, f: F)
2620 where F: FnOnce(&mut Resolver<'_>)
2622 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2623 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2625 self.ribs[TypeNS].pop();
2626 self.ribs[ValueNS].pop();
2629 fn with_constant_rib<F>(&mut self, f: F)
2630 where F: FnOnce(&mut Resolver<'_>)
2632 debug!("with_constant_rib");
2633 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2634 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2636 self.label_ribs.pop();
2637 self.ribs[ValueNS].pop();
2640 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2641 where F: FnOnce(&mut Resolver<'_>) -> T
2643 // Handle nested impls (inside fn bodies)
2644 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2645 let result = f(self);
2646 self.current_self_type = previous_value;
2650 fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
2651 where F: FnOnce(&mut Resolver<'_>) -> T
2653 let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
2654 let result = f(self);
2655 self.current_self_item = previous_value;
2659 /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
2660 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2661 where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
2663 let mut new_val = None;
2664 let mut new_id = None;
2665 if let Some(trait_ref) = opt_trait_ref {
2666 let path: Vec<_> = Segment::from_path(&trait_ref.path);
2667 let def = self.smart_resolve_path_fragment(
2671 trait_ref.path.span,
2672 PathSource::Trait(AliasPossibility::No),
2673 CrateLint::SimplePath(trait_ref.ref_id),
2675 if def != Def::Err {
2676 new_id = Some(def.def_id());
2677 let span = trait_ref.path.span;
2678 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2679 self.resolve_path_without_parent_scope(
2684 CrateLint::SimplePath(trait_ref.ref_id),
2687 new_val = Some((module, trait_ref.clone()));
2691 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2692 let result = f(self, new_id);
2693 self.current_trait_ref = original_trait_ref;
2697 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2698 where F: FnOnce(&mut Resolver<'_>)
2700 let mut self_type_rib = Rib::new(NormalRibKind);
2702 // plain insert (no renaming, types are not currently hygienic....)
2703 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2704 self.ribs[TypeNS].push(self_type_rib);
2706 self.ribs[TypeNS].pop();
2709 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2710 where F: FnOnce(&mut Resolver<'_>)
2712 let self_def = Def::SelfCtor(impl_id);
2713 let mut self_type_rib = Rib::new(NormalRibKind);
2714 self_type_rib.bindings.insert(keywords::SelfUpper.ident(), self_def);
2715 self.ribs[ValueNS].push(self_type_rib);
2717 self.ribs[ValueNS].pop();
2720 fn resolve_implementation(&mut self,
2721 generics: &Generics,
2722 opt_trait_reference: &Option<TraitRef>,
2725 impl_items: &[ImplItem]) {
2726 debug!("resolve_implementation");
2727 // If applicable, create a rib for the type parameters.
2728 self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
2729 // Dummy self type for better errors if `Self` is used in the trait path.
2730 this.with_self_rib(Def::SelfTy(None, None), |this| {
2731 // Resolve the trait reference, if necessary.
2732 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2733 let item_def_id = this.definitions.local_def_id(item_id);
2734 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2735 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2736 // Resolve type arguments in the trait path.
2737 visit::walk_trait_ref(this, trait_ref);
2739 // Resolve the self type.
2740 this.visit_ty(self_type);
2741 // Resolve the generic parameters.
2742 this.visit_generics(generics);
2743 // Resolve the items within the impl.
2744 this.with_current_self_type(self_type, |this| {
2745 this.with_self_struct_ctor_rib(item_def_id, |this| {
2746 debug!("resolve_implementation with_self_struct_ctor_rib");
2747 for impl_item in impl_items {
2748 this.resolve_visibility(&impl_item.vis);
2750 // We also need a new scope for the impl item type parameters.
2751 let generic_params = HasGenericParams(&impl_item.generics,
2752 TraitOrImplItemRibKind);
2753 this.with_generic_param_rib(generic_params, |this| {
2754 use self::ResolutionError::*;
2755 match impl_item.node {
2756 ImplItemKind::Const(..) => {
2758 "resolve_implementation ImplItemKind::Const",
2760 // If this is a trait impl, ensure the const
2762 this.check_trait_item(
2766 |n, s| ConstNotMemberOfTrait(n, s),
2769 this.with_constant_rib(|this| {
2770 visit::walk_impl_item(this, impl_item)
2773 ImplItemKind::Method(..) => {
2774 // If this is a trait impl, ensure the method
2776 this.check_trait_item(impl_item.ident,
2779 |n, s| MethodNotMemberOfTrait(n, s));
2781 visit::walk_impl_item(this, impl_item);
2783 ImplItemKind::Type(ref ty) => {
2784 // If this is a trait impl, ensure the type
2786 this.check_trait_item(impl_item.ident,
2789 |n, s| TypeNotMemberOfTrait(n, s));
2793 ImplItemKind::Existential(ref bounds) => {
2794 // If this is a trait impl, ensure the type
2796 this.check_trait_item(impl_item.ident,
2799 |n, s| TypeNotMemberOfTrait(n, s));
2801 for bound in bounds {
2802 this.visit_param_bound(bound);
2805 ImplItemKind::Macro(_) =>
2806 panic!("unexpanded macro in resolve!"),
2818 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2819 where F: FnOnce(Name, &str) -> ResolutionError<'_>
2821 // If there is a TraitRef in scope for an impl, then the method must be in the
2823 if let Some((module, _)) = self.current_trait_ref {
2824 if self.resolve_ident_in_module(
2825 ModuleOrUniformRoot::Module(module),
2832 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2833 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2838 fn resolve_local(&mut self, local: &Local) {
2839 // Resolve the type.
2840 walk_list!(self, visit_ty, &local.ty);
2842 // Resolve the initializer.
2843 walk_list!(self, visit_expr, &local.init);
2845 // Resolve the pattern.
2846 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap::default());
2849 // build a map from pattern identifiers to binding-info's.
2850 // this is done hygienically. This could arise for a macro
2851 // that expands into an or-pattern where one 'x' was from the
2852 // user and one 'x' came from the macro.
2853 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2854 let mut binding_map = FxHashMap::default();
2856 pat.walk(&mut |pat| {
2857 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2858 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2859 Some(Def::Local(..)) => true,
2862 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2863 binding_map.insert(ident, binding_info);
2872 // check that all of the arms in an or-pattern have exactly the
2873 // same set of bindings, with the same binding modes for each.
2874 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2875 if pats.is_empty() {
2879 let mut missing_vars = FxHashMap::default();
2880 let mut inconsistent_vars = FxHashMap::default();
2881 for (i, p) in pats.iter().enumerate() {
2882 let map_i = self.binding_mode_map(&p);
2884 for (j, q) in pats.iter().enumerate() {
2889 let map_j = self.binding_mode_map(&q);
2890 for (&key, &binding_i) in &map_i {
2891 if map_j.is_empty() { // Account for missing bindings when
2892 let binding_error = missing_vars // map_j has none.
2894 .or_insert(BindingError {
2896 origin: BTreeSet::new(),
2897 target: BTreeSet::new(),
2899 binding_error.origin.insert(binding_i.span);
2900 binding_error.target.insert(q.span);
2902 for (&key_j, &binding_j) in &map_j {
2903 match map_i.get(&key_j) {
2904 None => { // missing binding
2905 let binding_error = missing_vars
2907 .or_insert(BindingError {
2909 origin: BTreeSet::new(),
2910 target: BTreeSet::new(),
2912 binding_error.origin.insert(binding_j.span);
2913 binding_error.target.insert(p.span);
2915 Some(binding_i) => { // check consistent binding
2916 if binding_i.binding_mode != binding_j.binding_mode {
2919 .or_insert((binding_j.span, binding_i.span));
2927 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2928 missing_vars.sort();
2929 for (_, v) in missing_vars {
2931 *v.origin.iter().next().unwrap(),
2932 ResolutionError::VariableNotBoundInPattern(v));
2934 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2935 inconsistent_vars.sort();
2936 for (name, v) in inconsistent_vars {
2937 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2941 fn resolve_arm(&mut self, arm: &Arm) {
2942 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2944 let mut bindings_list = FxHashMap::default();
2945 for pattern in &arm.pats {
2946 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2949 // This has to happen *after* we determine which pat_idents are variants.
2950 self.check_consistent_bindings(&arm.pats);
2952 if let Some(ast::Guard::If(ref expr)) = arm.guard {
2953 self.visit_expr(expr)
2955 self.visit_expr(&arm.body);
2957 self.ribs[ValueNS].pop();
2960 fn resolve_block(&mut self, block: &Block) {
2961 debug!("(resolving block) entering block");
2962 // Move down in the graph, if there's an anonymous module rooted here.
2963 let orig_module = self.current_module;
2964 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2966 let mut num_macro_definition_ribs = 0;
2967 if let Some(anonymous_module) = anonymous_module {
2968 debug!("(resolving block) found anonymous module, moving down");
2969 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2970 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2971 self.current_module = anonymous_module;
2972 self.finalize_current_module_macro_resolutions();
2974 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2977 // Descend into the block.
2978 for stmt in &block.stmts {
2979 if let ast::StmtKind::Item(ref item) = stmt.node {
2980 if let ast::ItemKind::MacroDef(..) = item.node {
2981 num_macro_definition_ribs += 1;
2982 let def = self.definitions.local_def_id(item.id);
2983 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2984 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2988 self.visit_stmt(stmt);
2992 self.current_module = orig_module;
2993 for _ in 0 .. num_macro_definition_ribs {
2994 self.ribs[ValueNS].pop();
2995 self.label_ribs.pop();
2997 self.ribs[ValueNS].pop();
2998 if anonymous_module.is_some() {
2999 self.ribs[TypeNS].pop();
3001 debug!("(resolving block) leaving block");
3004 fn fresh_binding(&mut self,
3007 outer_pat_id: NodeId,
3008 pat_src: PatternSource,
3009 bindings: &mut FxHashMap<Ident, NodeId>)
3011 // Add the binding to the local ribs, if it
3012 // doesn't already exist in the bindings map. (We
3013 // must not add it if it's in the bindings map
3014 // because that breaks the assumptions later
3015 // passes make about or-patterns.)
3016 let ident = ident.modern_and_legacy();
3017 let mut def = Def::Local(pat_id);
3018 match bindings.get(&ident).cloned() {
3019 Some(id) if id == outer_pat_id => {
3020 // `Variant(a, a)`, error
3024 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
3028 Some(..) if pat_src == PatternSource::FnParam => {
3029 // `fn f(a: u8, a: u8)`, error
3033 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
3037 Some(..) if pat_src == PatternSource::Match ||
3038 pat_src == PatternSource::IfLet ||
3039 pat_src == PatternSource::WhileLet => {
3040 // `Variant1(a) | Variant2(a)`, ok
3041 // Reuse definition from the first `a`.
3042 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
3045 span_bug!(ident.span, "two bindings with the same name from \
3046 unexpected pattern source {:?}", pat_src);
3049 // A completely fresh binding, add to the lists if it's valid.
3050 if ident.name != keywords::Invalid.name() {
3051 bindings.insert(ident, outer_pat_id);
3052 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
3057 PathResolution::new(def)
3060 fn resolve_pattern(&mut self,
3062 pat_src: PatternSource,
3063 // Maps idents to the node ID for the
3064 // outermost pattern that binds them.
3065 bindings: &mut FxHashMap<Ident, NodeId>) {
3066 // Visit all direct subpatterns of this pattern.
3067 let outer_pat_id = pat.id;
3068 pat.walk(&mut |pat| {
3069 debug!("resolve_pattern pat={:?} node={:?}", pat, pat.node);
3071 PatKind::Ident(bmode, ident, ref opt_pat) => {
3072 // First try to resolve the identifier as some existing
3073 // entity, then fall back to a fresh binding.
3074 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
3076 .and_then(LexicalScopeBinding::item);
3077 let resolution = binding.map(NameBinding::def).and_then(|def| {
3078 let is_syntactic_ambiguity = opt_pat.is_none() &&
3079 bmode == BindingMode::ByValue(Mutability::Immutable);
3081 Def::StructCtor(_, CtorKind::Const) |
3082 Def::VariantCtor(_, CtorKind::Const) |
3083 Def::Const(..) if is_syntactic_ambiguity => {
3084 // Disambiguate in favor of a unit struct/variant
3085 // or constant pattern.
3086 self.record_use(ident, ValueNS, binding.unwrap(), false);
3087 Some(PathResolution::new(def))
3089 Def::StructCtor(..) | Def::VariantCtor(..) |
3090 Def::Const(..) | Def::Static(..) => {
3091 // This is unambiguously a fresh binding, either syntactically
3092 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
3093 // to something unusable as a pattern (e.g., constructor function),
3094 // but we still conservatively report an error, see
3095 // issues/33118#issuecomment-233962221 for one reason why.
3099 ResolutionError::BindingShadowsSomethingUnacceptable(
3100 pat_src.descr(), ident.name, binding.unwrap())
3104 Def::Fn(..) | Def::Err => {
3105 // These entities are explicitly allowed
3106 // to be shadowed by fresh bindings.
3110 span_bug!(ident.span, "unexpected definition for an \
3111 identifier in pattern: {:?}", def);
3114 }).unwrap_or_else(|| {
3115 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
3118 self.record_def(pat.id, resolution);
3121 PatKind::TupleStruct(ref path, ..) => {
3122 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
3125 PatKind::Path(ref qself, ref path) => {
3126 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
3129 PatKind::Struct(ref path, ..) => {
3130 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
3138 visit::walk_pat(self, pat);
3141 // High-level and context dependent path resolution routine.
3142 // Resolves the path and records the resolution into definition map.
3143 // If resolution fails tries several techniques to find likely
3144 // resolution candidates, suggest imports or other help, and report
3145 // errors in user friendly way.
3146 fn smart_resolve_path(&mut self,
3148 qself: Option<&QSelf>,
3150 source: PathSource<'_>)
3152 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
3155 /// A variant of `smart_resolve_path` where you also specify extra
3156 /// information about where the path came from; this extra info is
3157 /// sometimes needed for the lint that recommends rewriting
3158 /// absolute paths to `crate`, so that it knows how to frame the
3159 /// suggestion. If you are just resolving a path like `foo::bar`
3160 /// that appears...somewhere, though, then you just want
3161 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
3162 /// already provides.
3163 fn smart_resolve_path_with_crate_lint(
3166 qself: Option<&QSelf>,
3168 source: PathSource<'_>,
3169 crate_lint: CrateLint
3170 ) -> PathResolution {
3171 self.smart_resolve_path_fragment(
3174 &Segment::from_path(path),
3181 fn smart_resolve_path_fragment(&mut self,
3183 qself: Option<&QSelf>,
3186 source: PathSource<'_>,
3187 crate_lint: CrateLint)
3189 let ident_span = path.last().map_or(span, |ident| ident.ident.span);
3190 let ns = source.namespace();
3191 let is_expected = &|def| source.is_expected(def);
3192 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
3194 // Base error is amended with one short label and possibly some longer helps/notes.
3195 let report_errors = |this: &mut Self, def: Option<Def>| {
3196 // Make the base error.
3197 let expected = source.descr_expected();
3198 let path_str = Segment::names_to_string(path);
3199 let item_str = path.last().unwrap().ident;
3200 let code = source.error_code(def.is_some());
3201 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
3202 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
3203 format!("not a {}", expected),
3206 let item_span = path.last().unwrap().ident.span;
3207 let (mod_prefix, mod_str) = if path.len() == 1 {
3208 (String::new(), "this scope".to_string())
3209 } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
3210 (String::new(), "the crate root".to_string())
3212 let mod_path = &path[..path.len() - 1];
3213 let mod_prefix = match this.resolve_path_without_parent_scope(
3214 mod_path, Some(TypeNS), false, span, CrateLint::No
3216 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3219 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
3220 (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
3222 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
3223 format!("not found in {}", mod_str),
3227 let code = DiagnosticId::Error(code.into());
3228 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
3230 // Emit help message for fake-self from other languages like `this`(javascript)
3231 if ["this", "my"].contains(&&*item_str.as_str())
3232 && this.self_value_is_available(path[0].ident.span, span) {
3233 err.span_suggestion(
3237 Applicability::MaybeIncorrect,
3241 // Emit special messages for unresolved `Self` and `self`.
3242 if is_self_type(path, ns) {
3243 __diagnostic_used!(E0411);
3244 err.code(DiagnosticId::Error("E0411".into()));
3245 err.span_label(span, format!("`Self` is only available in impls, traits, \
3246 and type definitions"));
3247 return (err, Vec::new());
3249 if is_self_value(path, ns) {
3250 debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
3252 __diagnostic_used!(E0424);
3253 err.code(DiagnosticId::Error("E0424".into()));
3254 err.span_label(span, match source {
3255 PathSource::Pat => {
3256 format!("`self` value is a keyword \
3257 and may not be bound to \
3258 variables or shadowed")
3261 format!("`self` value is a keyword \
3262 only available in methods \
3263 with `self` parameter")
3266 return (err, Vec::new());
3269 // Try to lookup the name in more relaxed fashion for better error reporting.
3270 let ident = path.last().unwrap().ident;
3271 let candidates = this.lookup_import_candidates(ident, ns, is_expected);
3272 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3273 let enum_candidates =
3274 this.lookup_import_candidates(ident, ns, is_enum_variant);
3275 let mut enum_candidates = enum_candidates.iter()
3277 import_candidate_to_enum_paths(&suggestion)
3278 }).collect::<Vec<_>>();
3279 enum_candidates.sort();
3281 if !enum_candidates.is_empty() {
3282 // contextualize for E0412 "cannot find type", but don't belabor the point
3283 // (that it's a variant) for E0573 "expected type, found variant"
3284 let preamble = if def.is_none() {
3285 let others = match enum_candidates.len() {
3287 2 => " and 1 other".to_owned(),
3288 n => format!(" and {} others", n)
3290 format!("there is an enum variant `{}`{}; ",
3291 enum_candidates[0].0, others)
3295 let msg = format!("{}try using the variant's enum", preamble);
3297 err.span_suggestions(
3300 enum_candidates.into_iter()
3301 .map(|(_variant_path, enum_ty_path)| enum_ty_path)
3302 // variants reëxported in prelude doesn't mean `prelude::v1` is the
3303 // type name! FIXME: is there a more principled way to do this that
3304 // would work for other reëxports?
3305 .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
3306 // also say `Option` rather than `std::prelude::v1::Option`
3307 .map(|enum_ty_path| {
3308 // FIXME #56861: DRYer prelude filtering
3309 enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
3311 Applicability::MachineApplicable,
3315 if path.len() == 1 && this.self_type_is_available(span) {
3316 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3317 let self_is_available = this.self_value_is_available(path[0].ident.span, span);
3319 AssocSuggestion::Field => {
3320 err.span_suggestion(
3323 format!("self.{}", path_str),
3324 Applicability::MachineApplicable,
3326 if !self_is_available {
3327 err.span_label(span, format!("`self` value is a keyword \
3329 methods with `self` parameter"));
3332 AssocSuggestion::MethodWithSelf if self_is_available => {
3333 err.span_suggestion(
3336 format!("self.{}", path_str),
3337 Applicability::MachineApplicable,
3340 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3341 err.span_suggestion(
3344 format!("Self::{}", path_str),
3345 Applicability::MachineApplicable,
3349 return (err, candidates);
3353 let mut levenshtein_worked = false;
3355 // Try Levenshtein algorithm.
3356 let suggestion = this.lookup_typo_candidate(path, ns, is_expected, span);
3357 if let Some(suggestion) = suggestion {
3359 "{} {} with a similar name exists",
3360 suggestion.article, suggestion.kind
3362 err.span_suggestion(
3365 suggestion.candidate.to_string(),
3366 Applicability::MaybeIncorrect,
3369 levenshtein_worked = true;
3372 // Try context dependent help if relaxed lookup didn't work.
3373 if let Some(def) = def {
3374 match (def, source) {
3375 (Def::Macro(..), _) => {
3376 err.span_suggestion(
3378 "use `!` to invoke the macro",
3379 format!("{}!", path_str),
3380 Applicability::MaybeIncorrect,
3382 return (err, candidates);
3384 (Def::TyAlias(..), PathSource::Trait(_)) => {
3385 err.span_label(span, "type aliases cannot be used as traits");
3386 if nightly_options::is_nightly_build() {
3387 err.note("did you mean to use a trait alias?");
3389 return (err, candidates);
3391 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3392 ExprKind::Field(_, ident) => {
3393 err.span_suggestion(
3395 "use the path separator to refer to an item",
3396 format!("{}::{}", path_str, ident),
3397 Applicability::MaybeIncorrect,
3399 return (err, candidates);
3401 ExprKind::MethodCall(ref segment, ..) => {
3402 let span = parent.span.with_hi(segment.ident.span.hi());
3403 err.span_suggestion(
3405 "use the path separator to refer to an item",
3406 format!("{}::{}", path_str, segment.ident),
3407 Applicability::MaybeIncorrect,
3409 return (err, candidates);
3413 (Def::Enum(..), PathSource::TupleStruct)
3414 | (Def::Enum(..), PathSource::Expr(..)) => {
3415 if let Some(variants) = this.collect_enum_variants(def) {
3416 err.note(&format!("did you mean to use one \
3417 of the following variants?\n{}",
3419 .map(|suggestion| path_names_to_string(suggestion))
3420 .map(|suggestion| format!("- `{}`", suggestion))
3421 .collect::<Vec<_>>()
3425 err.note("did you mean to use one of the enum's variants?");
3427 return (err, candidates);
3429 (Def::Struct(def_id), _) if ns == ValueNS => {
3430 if let Some((ctor_def, ctor_vis))
3431 = this.struct_constructors.get(&def_id).cloned() {
3432 let accessible_ctor = this.is_accessible(ctor_vis);
3433 if is_expected(ctor_def) && !accessible_ctor {
3434 err.span_label(span, format!("constructor is not visible \
3435 here due to private fields"));
3438 // HACK(estebank): find a better way to figure out that this was a
3439 // parser issue where a struct literal is being used on an expression
3440 // where a brace being opened means a block is being started. Look
3441 // ahead for the next text to see if `span` is followed by a `{`.
3442 let sm = this.session.source_map();
3445 sp = sm.next_point(sp);
3446 match sm.span_to_snippet(sp) {
3447 Ok(ref snippet) => {
3448 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3455 let followed_by_brace = match sm.span_to_snippet(sp) {
3456 Ok(ref snippet) if snippet == "{" => true,
3459 // In case this could be a struct literal that needs to be surrounded
3460 // by parenthesis, find the appropriate span.
3462 let mut closing_brace = None;
3464 sp = sm.next_point(sp);
3465 match sm.span_to_snippet(sp) {
3466 Ok(ref snippet) => {
3468 let sp = span.to(sp);
3469 if let Ok(snippet) = sm.span_to_snippet(sp) {
3470 closing_brace = Some((sp, snippet));
3478 if i > 100 { // The bigger the span the more likely we're
3479 break; // incorrect. Bound it to 100 chars long.
3483 PathSource::Expr(Some(parent)) => {
3485 ExprKind::MethodCall(ref path_assignment, _) => {
3486 err.span_suggestion(
3487 sm.start_point(parent.span)
3488 .to(path_assignment.ident.span),
3489 "use `::` to access an associated function",
3492 path_assignment.ident),
3493 Applicability::MaybeIncorrect
3495 return (err, candidates);
3500 format!("did you mean `{} {{ /* fields */ }}`?",
3503 return (err, candidates);
3507 PathSource::Expr(None) if followed_by_brace == true => {
3508 if let Some((sp, snippet)) = closing_brace {
3509 err.span_suggestion(
3511 "surround the struct literal with parenthesis",
3512 format!("({})", snippet),
3513 Applicability::MaybeIncorrect,
3518 format!("did you mean `({} {{ /* fields */ }})`?",
3522 return (err, candidates);
3527 format!("did you mean `{} {{ /* fields */ }}`?",
3530 return (err, candidates);
3534 return (err, candidates);
3536 (Def::Union(..), _) |
3537 (Def::Variant(..), _) |
3538 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3539 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3541 return (err, candidates);
3543 (Def::SelfTy(..), _) if ns == ValueNS => {
3544 err.span_label(span, fallback_label);
3545 err.note("can't use `Self` as a constructor, you must use the \
3546 implemented struct");
3547 return (err, candidates);
3549 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3550 err.note("can't use a type alias as a constructor");
3551 return (err, candidates);
3558 if !levenshtein_worked {
3559 err.span_label(base_span, fallback_label);
3560 this.type_ascription_suggestion(&mut err, base_span);
3564 let report_errors = |this: &mut Self, def: Option<Def>| {
3565 let (err, candidates) = report_errors(this, def);
3566 let def_id = this.current_module.normal_ancestor_id;
3567 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3568 let better = def.is_some();
3569 this.use_injections.push(UseError { err, candidates, node_id, better });
3570 err_path_resolution()
3573 let resolution = match self.resolve_qpath_anywhere(
3579 source.defer_to_typeck(),
3580 source.global_by_default(),
3583 Some(resolution) if resolution.unresolved_segments() == 0 => {
3584 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3587 // Add a temporary hack to smooth the transition to new struct ctor
3588 // visibility rules. See #38932 for more details.
3590 if let Def::Struct(def_id) = resolution.base_def() {
3591 if let Some((ctor_def, ctor_vis))
3592 = self.struct_constructors.get(&def_id).cloned() {
3593 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3594 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3595 self.session.buffer_lint(lint, id, span,
3596 "private struct constructors are not usable through \
3597 re-exports in outer modules",
3599 res = Some(PathResolution::new(ctor_def));
3604 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3607 Some(resolution) if source.defer_to_typeck() => {
3608 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3609 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3610 // it needs to be added to the trait map.
3612 let item_name = path.last().unwrap().ident;
3613 let traits = self.get_traits_containing_item(item_name, ns);
3614 self.trait_map.insert(id, traits);
3618 _ => report_errors(self, None)
3621 if let PathSource::TraitItem(..) = source {} else {
3622 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3623 self.record_def(id, resolution);
3628 fn type_ascription_suggestion(&self,
3629 err: &mut DiagnosticBuilder<'_>,
3631 debug!("type_ascription_suggetion {:?}", base_span);
3632 let cm = self.session.source_map();
3633 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3634 if let Some(sp) = self.current_type_ascription.last() {
3636 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3637 sp = cm.next_point(sp);
3638 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3639 debug!("snippet {:?}", snippet);
3640 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3641 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3642 debug!("{:?} {:?}", line_sp, line_base_sp);
3644 err.span_label(base_span,
3645 "expecting a type here because of type ascription");
3646 if line_sp != line_base_sp {
3647 err.span_suggestion_short(
3649 "did you mean to use `;` here instead?",
3651 Applicability::MaybeIncorrect,
3655 } else if !snippet.trim().is_empty() {
3656 debug!("tried to find type ascription `:` token, couldn't find it");
3666 fn self_type_is_available(&mut self, span: Span) -> bool {
3667 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfUpper.ident(),
3668 TypeNS, None, span);
3669 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3672 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3673 let ident = Ident::new(keywords::SelfLower.name(), self_span);
3674 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3675 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3678 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3679 fn resolve_qpath_anywhere(&mut self,
3681 qself: Option<&QSelf>,
3683 primary_ns: Namespace,
3685 defer_to_typeck: bool,
3686 global_by_default: bool,
3687 crate_lint: CrateLint)
3688 -> Option<PathResolution> {
3689 let mut fin_res = None;
3690 // FIXME: can't resolve paths in macro namespace yet, macros are
3691 // processed by the little special hack below.
3692 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3693 if i == 0 || ns != primary_ns {
3694 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3695 // If defer_to_typeck, then resolution > no resolution,
3696 // otherwise full resolution > partial resolution > no resolution.
3697 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3699 res => if fin_res.is_none() { fin_res = res },
3703 if primary_ns != MacroNS &&
3704 (self.macro_names.contains(&path[0].ident.modern()) ||
3705 self.builtin_macros.get(&path[0].ident.name).cloned()
3706 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3707 self.macro_use_prelude.get(&path[0].ident.name).cloned()
3708 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3709 // Return some dummy definition, it's enough for error reporting.
3711 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3717 /// Handles paths that may refer to associated items.
3718 fn resolve_qpath(&mut self,
3720 qself: Option<&QSelf>,
3724 global_by_default: bool,
3725 crate_lint: CrateLint)
3726 -> Option<PathResolution> {
3728 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3729 ns={:?}, span={:?}, global_by_default={:?})",
3738 if let Some(qself) = qself {
3739 if qself.position == 0 {
3740 // This is a case like `<T>::B`, where there is no
3741 // trait to resolve. In that case, we leave the `B`
3742 // segment to be resolved by type-check.
3743 return Some(PathResolution::with_unresolved_segments(
3744 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3748 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3750 // Currently, `path` names the full item (`A::B::C`, in
3751 // our example). so we extract the prefix of that that is
3752 // the trait (the slice upto and including
3753 // `qself.position`). And then we recursively resolve that,
3754 // but with `qself` set to `None`.
3756 // However, setting `qself` to none (but not changing the
3757 // span) loses the information about where this path
3758 // *actually* appears, so for the purposes of the crate
3759 // lint we pass along information that this is the trait
3760 // name from a fully qualified path, and this also
3761 // contains the full span (the `CrateLint::QPathTrait`).
3762 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3763 let res = self.smart_resolve_path_fragment(
3766 &path[..=qself.position],
3768 PathSource::TraitItem(ns),
3769 CrateLint::QPathTrait {
3771 qpath_span: qself.path_span,
3775 // The remaining segments (the `C` in our example) will
3776 // have to be resolved by type-check, since that requires doing
3777 // trait resolution.
3778 return Some(PathResolution::with_unresolved_segments(
3779 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3783 let result = match self.resolve_path_without_parent_scope(
3790 PathResult::NonModule(path_res) => path_res,
3791 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3792 PathResolution::new(module.def().unwrap())
3794 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3795 // don't report an error right away, but try to fallback to a primitive type.
3796 // So, we are still able to successfully resolve something like
3798 // use std::u8; // bring module u8 in scope
3799 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3800 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3801 // // not to non-existent std::u8::max_value
3804 // Such behavior is required for backward compatibility.
3805 // The same fallback is used when `a` resolves to nothing.
3806 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3807 PathResult::Failed(..)
3808 if (ns == TypeNS || path.len() > 1) &&
3809 self.primitive_type_table.primitive_types
3810 .contains_key(&path[0].ident.name) => {
3811 let prim = self.primitive_type_table.primitive_types[&path[0].ident.name];
3812 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3814 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3815 PathResolution::new(module.def().unwrap()),
3816 PathResult::Failed(span, msg, false) => {
3817 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3818 err_path_resolution()
3820 PathResult::Module(..) | PathResult::Failed(..) => return None,
3821 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3824 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3825 path[0].ident.name != keywords::PathRoot.name() &&
3826 path[0].ident.name != keywords::DollarCrate.name() {
3827 let unqualified_result = {
3828 match self.resolve_path_without_parent_scope(
3829 &[*path.last().unwrap()],
3835 PathResult::NonModule(path_res) => path_res.base_def(),
3836 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3837 module.def().unwrap(),
3838 _ => return Some(result),
3841 if result.base_def() == unqualified_result {
3842 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3843 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3850 fn resolve_path_without_parent_scope(
3853 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3856 crate_lint: CrateLint,
3857 ) -> PathResult<'a> {
3858 // Macro and import paths must have full parent scope available during resolution,
3859 // other paths will do okay with parent module alone.
3860 assert!(opt_ns != None && opt_ns != Some(MacroNS));
3861 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3862 self.resolve_path(path, opt_ns, &parent_scope, record_used, path_span, crate_lint)
3868 opt_ns: Option<Namespace>, // `None` indicates a module path in import
3869 parent_scope: &ParentScope<'a>,
3872 crate_lint: CrateLint,
3873 ) -> PathResult<'a> {
3874 let mut module = None;
3875 let mut allow_super = true;
3876 let mut second_binding = None;
3877 self.current_module = parent_scope.module;
3880 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3881 path_span={:?}, crate_lint={:?})",
3889 for (i, &Segment { ident, id }) in path.iter().enumerate() {
3890 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
3891 let record_segment_def = |this: &mut Self, def| {
3893 if let Some(id) = id {
3894 if !this.def_map.contains_key(&id) {
3895 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
3896 this.record_def(id, PathResolution::new(def));
3902 let is_last = i == path.len() - 1;
3903 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3904 let name = ident.name;
3906 allow_super &= ns == TypeNS &&
3907 (name == keywords::SelfLower.name() ||
3908 name == keywords::Super.name());
3911 if allow_super && name == keywords::Super.name() {
3912 let mut ctxt = ident.span.ctxt().modern();
3913 let self_module = match i {
3914 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3916 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3920 if let Some(self_module) = self_module {
3921 if let Some(parent) = self_module.parent {
3922 module = Some(ModuleOrUniformRoot::Module(
3923 self.resolve_self(&mut ctxt, parent)));
3927 let msg = "there are too many initial `super`s.".to_string();
3928 return PathResult::Failed(ident.span, msg, false);
3931 if name == keywords::SelfLower.name() {
3932 let mut ctxt = ident.span.ctxt().modern();
3933 module = Some(ModuleOrUniformRoot::Module(
3934 self.resolve_self(&mut ctxt, self.current_module)));
3937 if name == keywords::PathRoot.name() && ident.span.rust_2018() {
3938 module = Some(ModuleOrUniformRoot::ExternPrelude);
3941 if name == keywords::PathRoot.name() &&
3942 ident.span.rust_2015() && self.session.rust_2018() {
3943 // `::a::b` from 2015 macro on 2018 global edition
3944 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
3947 if name == keywords::PathRoot.name() ||
3948 name == keywords::Crate.name() ||
3949 name == keywords::DollarCrate.name() {
3950 // `::a::b`, `crate::a::b` or `$crate::a::b`
3951 module = Some(ModuleOrUniformRoot::Module(
3952 self.resolve_crate_root(ident)));
3958 // Report special messages for path segment keywords in wrong positions.
3959 if ident.is_path_segment_keyword() && i != 0 {
3960 let name_str = if name == keywords::PathRoot.name() {
3961 "crate root".to_string()
3963 format!("`{}`", name)
3965 let msg = if i == 1 && path[0].ident.name == keywords::PathRoot.name() {
3966 format!("global paths cannot start with {}", name_str)
3968 format!("{} in paths can only be used in start position", name_str)
3970 return PathResult::Failed(ident.span, msg, false);
3973 let binding = if let Some(module) = module {
3974 self.resolve_ident_in_module(module, ident, ns, None, record_used, path_span)
3975 } else if opt_ns.is_none() || opt_ns == Some(MacroNS) {
3976 assert!(ns == TypeNS);
3977 let scopes = if opt_ns.is_none() { ScopeSet::Import(ns) } else { ScopeSet::Module };
3978 self.early_resolve_ident_in_lexical_scope(ident, scopes, parent_scope, record_used,
3979 record_used, path_span)
3981 let record_used_id =
3982 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3983 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3984 // we found a locally-imported or available item/module
3985 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3986 // we found a local variable or type param
3987 Some(LexicalScopeBinding::Def(def))
3988 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3989 record_segment_def(self, def);
3990 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3994 _ => Err(Determinacy::determined(record_used)),
4001 second_binding = Some(binding);
4003 let def = binding.def();
4004 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
4005 if let Some(next_module) = binding.module() {
4006 module = Some(ModuleOrUniformRoot::Module(next_module));
4007 record_segment_def(self, def);
4008 } else if def == Def::ToolMod && i + 1 != path.len() {
4009 if binding.is_import() {
4010 self.session.struct_span_err(
4011 ident.span, "cannot use a tool module through an import"
4013 binding.span, "the tool module imported here"
4016 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
4017 return PathResult::NonModule(PathResolution::new(def));
4018 } else if def == Def::Err {
4019 return PathResult::NonModule(err_path_resolution());
4020 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
4021 self.lint_if_path_starts_with_module(
4027 return PathResult::NonModule(PathResolution::with_unresolved_segments(
4028 def, path.len() - i - 1
4031 return PathResult::Failed(ident.span,
4032 format!("not a module `{}`", ident),
4036 Err(Undetermined) => return PathResult::Indeterminate,
4037 Err(Determined) => {
4038 if let Some(ModuleOrUniformRoot::Module(module)) = module {
4039 if opt_ns.is_some() && !module.is_normal() {
4040 return PathResult::NonModule(PathResolution::with_unresolved_segments(
4041 module.def().unwrap(), path.len() - i
4045 let module_def = match module {
4046 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
4049 let msg = if module_def == self.graph_root.def() {
4050 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
4051 let mut candidates =
4052 self.lookup_import_candidates(ident, TypeNS, is_mod);
4053 candidates.sort_by_cached_key(|c| {
4054 (c.path.segments.len(), c.path.to_string())
4056 if let Some(candidate) = candidates.get(0) {
4057 format!("did you mean `{}`?", candidate.path)
4058 } else if !ident.is_reserved() {
4059 format!("maybe a missing `extern crate {};`?", ident)
4061 // the parser will already have complained about the keyword being used
4062 return PathResult::NonModule(err_path_resolution());
4065 format!("use of undeclared type or module `{}`", ident)
4067 format!("could not find `{}` in `{}`", ident, path[i - 1].ident)
4069 return PathResult::Failed(ident.span, msg, is_last);
4074 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
4076 PathResult::Module(match module {
4077 Some(module) => module,
4078 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
4079 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
4083 fn lint_if_path_starts_with_module(
4085 crate_lint: CrateLint,
4088 second_binding: Option<&NameBinding<'_>>,
4090 let (diag_id, diag_span) = match crate_lint {
4091 CrateLint::No => return,
4092 CrateLint::SimplePath(id) => (id, path_span),
4093 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
4094 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
4097 let first_name = match path.get(0) {
4098 // In the 2018 edition this lint is a hard error, so nothing to do
4099 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
4103 // We're only interested in `use` paths which should start with
4104 // `{{root}}` currently.
4105 if first_name != keywords::PathRoot.name() {
4110 // If this import looks like `crate::...` it's already good
4111 Some(Segment { ident, .. }) if ident.name == keywords::Crate.name() => return,
4112 // Otherwise go below to see if it's an extern crate
4114 // If the path has length one (and it's `PathRoot` most likely)
4115 // then we don't know whether we're gonna be importing a crate or an
4116 // item in our crate. Defer this lint to elsewhere
4120 // If the first element of our path was actually resolved to an
4121 // `ExternCrate` (also used for `crate::...`) then no need to issue a
4122 // warning, this looks all good!
4123 if let Some(binding) = second_binding {
4124 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
4125 // Careful: we still want to rewrite paths from
4126 // renamed extern crates.
4127 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
4133 let diag = lint::builtin::BuiltinLintDiagnostics
4134 ::AbsPathWithModule(diag_span);
4135 self.session.buffer_lint_with_diagnostic(
4136 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
4138 "absolute paths must start with `self`, `super`, \
4139 `crate`, or an external crate name in the 2018 edition",
4143 // Resolve a local definition, potentially adjusting for closures.
4144 fn adjust_local_def(&mut self,
4149 span: Span) -> Def {
4150 debug!("adjust_local_def");
4151 let ribs = &self.ribs[ns][rib_index + 1..];
4153 // An invalid forward use of a type parameter from a previous default.
4154 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
4156 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
4158 assert_eq!(def, Def::Err);
4164 span_bug!(span, "unexpected {:?} in bindings", def)
4166 Def::Local(node_id) => {
4169 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
4170 ForwardTyParamBanRibKind => {
4171 // Nothing to do. Continue.
4173 ClosureRibKind(function_id) => {
4176 let seen = self.freevars_seen
4179 if let Some(&index) = seen.get(&node_id) {
4180 def = Def::Upvar(node_id, index, function_id);
4183 let vec = self.freevars
4186 let depth = vec.len();
4187 def = Def::Upvar(node_id, depth, function_id);
4194 seen.insert(node_id, depth);
4197 ItemRibKind | TraitOrImplItemRibKind => {
4198 // This was an attempt to access an upvar inside a
4199 // named function item. This is not allowed, so we
4202 resolve_error(self, span,
4203 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
4207 ConstantItemRibKind => {
4208 // Still doesn't deal with upvars
4210 resolve_error(self, span,
4211 ResolutionError::AttemptToUseNonConstantValueInConstant);
4218 Def::TyParam(..) | Def::SelfTy(..) => {
4221 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
4222 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
4223 ConstantItemRibKind => {
4224 // Nothing to do. Continue.
4227 // This was an attempt to use a type parameter outside its scope.
4232 ResolutionError::GenericParamsFromOuterFunction(def),
4240 Def::ConstParam(..) => {
4241 // A const param is always declared in a signature, which is always followed by
4242 // some kind of function rib kind (specifically, ItemRibKind in the case of a
4243 // normal function), so we can skip the first rib as it will be guaranteed to
4244 // (spuriously) conflict with the const param.
4245 for rib in &ribs[1..] {
4246 if let ItemRibKind = rib.kind {
4247 // This was an attempt to use a const parameter outside its scope.
4252 ResolutionError::GenericParamsFromOuterFunction(def),
4264 fn lookup_assoc_candidate<FilterFn>(&mut self,
4267 filter_fn: FilterFn)
4268 -> Option<AssocSuggestion>
4269 where FilterFn: Fn(Def) -> bool
4271 fn extract_node_id(t: &Ty) -> Option<NodeId> {
4273 TyKind::Path(None, _) => Some(t.id),
4274 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
4275 // This doesn't handle the remaining `Ty` variants as they are not
4276 // that commonly the self_type, it might be interesting to provide
4277 // support for those in future.
4282 // Fields are generally expected in the same contexts as locals.
4283 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
4284 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
4285 // Look for a field with the same name in the current self_type.
4286 if let Some(resolution) = self.def_map.get(&node_id) {
4287 match resolution.base_def() {
4288 Def::Struct(did) | Def::Union(did)
4289 if resolution.unresolved_segments() == 0 => {
4290 if let Some(field_names) = self.field_names.get(&did) {
4291 if field_names.iter().any(|&field_name| ident.name == field_name) {
4292 return Some(AssocSuggestion::Field);
4302 // Look for associated items in the current trait.
4303 if let Some((module, _)) = self.current_trait_ref {
4304 if let Ok(binding) = self.resolve_ident_in_module(
4305 ModuleOrUniformRoot::Module(module),
4312 let def = binding.def();
4314 return Some(if self.has_self.contains(&def.def_id()) {
4315 AssocSuggestion::MethodWithSelf
4317 AssocSuggestion::AssocItem
4326 fn lookup_typo_candidate<FilterFn>(
4330 filter_fn: FilterFn,
4332 ) -> Option<TypoSuggestion>
4334 FilterFn: Fn(Def) -> bool,
4336 let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
4337 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
4338 if let Some(binding) = resolution.borrow().binding {
4339 if filter_fn(binding.def()) {
4340 names.push(TypoSuggestion {
4341 candidate: ident.name,
4342 article: binding.def().article(),
4343 kind: binding.def().kind_name(),
4350 let mut names = Vec::new();
4351 if path.len() == 1 {
4352 // Search in lexical scope.
4353 // Walk backwards up the ribs in scope and collect candidates.
4354 for rib in self.ribs[ns].iter().rev() {
4355 // Locals and type parameters
4356 for (ident, def) in &rib.bindings {
4357 if filter_fn(*def) {
4358 names.push(TypoSuggestion {
4359 candidate: ident.name,
4360 article: def.article(),
4361 kind: def.kind_name(),
4366 if let ModuleRibKind(module) = rib.kind {
4367 // Items from this module
4368 add_module_candidates(module, &mut names);
4370 if let ModuleKind::Block(..) = module.kind {
4371 // We can see through blocks
4373 // Items from the prelude
4374 if !module.no_implicit_prelude {
4375 names.extend(self.extern_prelude.iter().map(|(ident, _)| {
4377 candidate: ident.name,
4382 if let Some(prelude) = self.prelude {
4383 add_module_candidates(prelude, &mut names);
4390 // Add primitive types to the mix
4391 if filter_fn(Def::PrimTy(Bool)) {
4393 self.primitive_type_table.primitive_types.iter().map(|(name, _)| {
4397 kind: "primitive type",
4403 // Search in module.
4404 let mod_path = &path[..path.len() - 1];
4405 if let PathResult::Module(module) = self.resolve_path_without_parent_scope(
4406 mod_path, Some(TypeNS), false, span, CrateLint::No
4408 if let ModuleOrUniformRoot::Module(module) = module {
4409 add_module_candidates(module, &mut names);
4414 let name = path[path.len() - 1].ident.name;
4415 // Make sure error reporting is deterministic.
4416 names.sort_by_cached_key(|suggestion| suggestion.candidate.as_str());
4418 match find_best_match_for_name(
4419 names.iter().map(|suggestion| &suggestion.candidate),
4423 Some(found) if found != name => names
4425 .find(|suggestion| suggestion.candidate == found),
4430 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
4431 where F: FnOnce(&mut Resolver<'_>)
4433 if let Some(label) = label {
4434 self.unused_labels.insert(id, label.ident.span);
4435 let def = Def::Label(id);
4436 self.with_label_rib(|this| {
4437 let ident = label.ident.modern_and_legacy();
4438 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4446 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4447 self.with_resolved_label(label, id, |this| this.visit_block(block));
4450 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4451 // First, record candidate traits for this expression if it could
4452 // result in the invocation of a method call.
4454 self.record_candidate_traits_for_expr_if_necessary(expr);
4456 // Next, resolve the node.
4458 ExprKind::Path(ref qself, ref path) => {
4459 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4460 visit::walk_expr(self, expr);
4463 ExprKind::Struct(ref path, ..) => {
4464 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4465 visit::walk_expr(self, expr);
4468 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4469 let def = self.search_label(label.ident, |rib, ident| {
4470 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4474 // Search again for close matches...
4475 // Picks the first label that is "close enough", which is not necessarily
4476 // the closest match
4477 let close_match = self.search_label(label.ident, |rib, ident| {
4478 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4479 find_best_match_for_name(names, &*ident.as_str(), None)
4481 self.record_def(expr.id, err_path_resolution());
4484 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4487 Some(Def::Label(id)) => {
4488 // Since this def is a label, it is never read.
4489 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4490 self.unused_labels.remove(&id);
4493 span_bug!(expr.span, "label wasn't mapped to a label def!");
4497 // visit `break` argument if any
4498 visit::walk_expr(self, expr);
4501 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4502 self.visit_expr(subexpression);
4504 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4505 let mut bindings_list = FxHashMap::default();
4507 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4509 // This has to happen *after* we determine which pat_idents are variants
4510 self.check_consistent_bindings(pats);
4511 self.visit_block(if_block);
4512 self.ribs[ValueNS].pop();
4514 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4517 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4519 ExprKind::While(ref subexpression, ref block, label) => {
4520 self.with_resolved_label(label, expr.id, |this| {
4521 this.visit_expr(subexpression);
4522 this.visit_block(block);
4526 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4527 self.with_resolved_label(label, expr.id, |this| {
4528 this.visit_expr(subexpression);
4529 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4530 let mut bindings_list = FxHashMap::default();
4532 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4534 // This has to happen *after* we determine which pat_idents are variants.
4535 this.check_consistent_bindings(pats);
4536 this.visit_block(block);
4537 this.ribs[ValueNS].pop();
4541 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4542 self.visit_expr(subexpression);
4543 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4544 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap::default());
4546 self.resolve_labeled_block(label, expr.id, block);
4548 self.ribs[ValueNS].pop();
4551 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4553 // Equivalent to `visit::walk_expr` + passing some context to children.
4554 ExprKind::Field(ref subexpression, _) => {
4555 self.resolve_expr(subexpression, Some(expr));
4557 ExprKind::MethodCall(ref segment, ref arguments) => {
4558 let mut arguments = arguments.iter();
4559 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4560 for argument in arguments {
4561 self.resolve_expr(argument, None);
4563 self.visit_path_segment(expr.span, segment);
4566 ExprKind::Call(ref callee, ref arguments) => {
4567 self.resolve_expr(callee, Some(expr));
4568 for argument in arguments {
4569 self.resolve_expr(argument, None);
4572 ExprKind::Type(ref type_expr, _) => {
4573 self.current_type_ascription.push(type_expr.span);
4574 visit::walk_expr(self, expr);
4575 self.current_type_ascription.pop();
4577 // Resolve the body of async exprs inside the async closure to which they desugar
4578 ExprKind::Async(_, async_closure_id, ref block) => {
4579 let rib_kind = ClosureRibKind(async_closure_id);
4580 self.ribs[ValueNS].push(Rib::new(rib_kind));
4581 self.label_ribs.push(Rib::new(rib_kind));
4582 self.visit_block(&block);
4583 self.label_ribs.pop();
4584 self.ribs[ValueNS].pop();
4586 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4587 // resolve the arguments within the proper scopes so that usages of them inside the
4588 // closure are detected as upvars rather than normal closure arg usages.
4590 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4591 ref fn_decl, ref body, _span,
4593 let rib_kind = ClosureRibKind(expr.id);
4594 self.ribs[ValueNS].push(Rib::new(rib_kind));
4595 self.label_ribs.push(Rib::new(rib_kind));
4596 // Resolve arguments:
4597 let mut bindings_list = FxHashMap::default();
4598 for argument in &fn_decl.inputs {
4599 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4600 self.visit_ty(&argument.ty);
4602 // No need to resolve return type-- the outer closure return type is
4603 // FunctionRetTy::Default
4605 // Now resolve the inner closure
4607 let rib_kind = ClosureRibKind(inner_closure_id);
4608 self.ribs[ValueNS].push(Rib::new(rib_kind));
4609 self.label_ribs.push(Rib::new(rib_kind));
4610 // No need to resolve arguments: the inner closure has none.
4611 // Resolve the return type:
4612 visit::walk_fn_ret_ty(self, &fn_decl.output);
4614 self.visit_expr(body);
4615 self.label_ribs.pop();
4616 self.ribs[ValueNS].pop();
4618 self.label_ribs.pop();
4619 self.ribs[ValueNS].pop();
4622 visit::walk_expr(self, expr);
4627 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4629 ExprKind::Field(_, ident) => {
4630 // FIXME(#6890): Even though you can't treat a method like a
4631 // field, we need to add any trait methods we find that match
4632 // the field name so that we can do some nice error reporting
4633 // later on in typeck.
4634 let traits = self.get_traits_containing_item(ident, ValueNS);
4635 self.trait_map.insert(expr.id, traits);
4637 ExprKind::MethodCall(ref segment, ..) => {
4638 debug!("(recording candidate traits for expr) recording traits for {}",
4640 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4641 self.trait_map.insert(expr.id, traits);
4649 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4650 -> Vec<TraitCandidate> {
4651 debug!("(getting traits containing item) looking for '{}'", ident.name);
4653 let mut found_traits = Vec::new();
4654 // Look for the current trait.
4655 if let Some((module, _)) = self.current_trait_ref {
4656 if self.resolve_ident_in_module(
4657 ModuleOrUniformRoot::Module(module),
4664 let def_id = module.def_id().unwrap();
4665 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4669 ident.span = ident.span.modern();
4670 let mut search_module = self.current_module;
4672 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4673 search_module = unwrap_or!(
4674 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4678 if let Some(prelude) = self.prelude {
4679 if !search_module.no_implicit_prelude {
4680 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4687 fn get_traits_in_module_containing_item(&mut self,
4691 found_traits: &mut Vec<TraitCandidate>) {
4692 assert!(ns == TypeNS || ns == ValueNS);
4693 let mut traits = module.traits.borrow_mut();
4694 if traits.is_none() {
4695 let mut collected_traits = Vec::new();
4696 module.for_each_child(|name, ns, binding| {
4697 if ns != TypeNS { return }
4698 if let Def::Trait(_) = binding.def() {
4699 collected_traits.push((name, binding));
4702 *traits = Some(collected_traits.into_boxed_slice());
4705 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4706 let module = binding.module().unwrap();
4707 let mut ident = ident;
4708 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4711 if self.resolve_ident_in_module_unadjusted(
4712 ModuleOrUniformRoot::Module(module),
4718 let import_id = match binding.kind {
4719 NameBindingKind::Import { directive, .. } => {
4720 self.maybe_unused_trait_imports.insert(directive.id);
4721 self.add_to_glob_map(&directive, trait_name);
4726 let trait_def_id = module.def_id().unwrap();
4727 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4732 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4733 lookup_ident: Ident,
4734 namespace: Namespace,
4735 start_module: &'a ModuleData<'a>,
4737 filter_fn: FilterFn)
4738 -> Vec<ImportSuggestion>
4739 where FilterFn: Fn(Def) -> bool
4741 let mut candidates = Vec::new();
4742 let mut seen_modules = FxHashSet::default();
4743 let not_local_module = crate_name != keywords::Crate.ident();
4744 let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)];
4746 while let Some((in_module,
4748 in_module_is_extern)) = worklist.pop() {
4749 self.populate_module_if_necessary(in_module);
4751 // We have to visit module children in deterministic order to avoid
4752 // instabilities in reported imports (#43552).
4753 in_module.for_each_child_stable(|ident, ns, name_binding| {
4754 // avoid imports entirely
4755 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4756 // avoid non-importable candidates as well
4757 if !name_binding.is_importable() { return; }
4759 // collect results based on the filter function
4760 if ident.name == lookup_ident.name && ns == namespace {
4761 if filter_fn(name_binding.def()) {
4763 let mut segms = path_segments.clone();
4764 if lookup_ident.span.rust_2018() {
4765 // crate-local absolute paths start with `crate::` in edition 2018
4766 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4768 0, ast::PathSegment::from_ident(crate_name)
4772 segms.push(ast::PathSegment::from_ident(ident));
4774 span: name_binding.span,
4777 // the entity is accessible in the following cases:
4778 // 1. if it's defined in the same crate, it's always
4779 // accessible (since private entities can be made public)
4780 // 2. if it's defined in another crate, it's accessible
4781 // only if both the module is public and the entity is
4782 // declared as public (due to pruning, we don't explore
4783 // outside crate private modules => no need to check this)
4784 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4785 candidates.push(ImportSuggestion { path });
4790 // collect submodules to explore
4791 if let Some(module) = name_binding.module() {
4793 let mut path_segments = path_segments.clone();
4794 path_segments.push(ast::PathSegment::from_ident(ident));
4796 let is_extern_crate_that_also_appears_in_prelude =
4797 name_binding.is_extern_crate() &&
4798 lookup_ident.span.rust_2018();
4800 let is_visible_to_user =
4801 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4803 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4804 // add the module to the lookup
4805 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4806 if seen_modules.insert(module.def_id().unwrap()) {
4807 worklist.push((module, path_segments, is_extern));
4817 /// When name resolution fails, this method can be used to look up candidate
4818 /// entities with the expected name. It allows filtering them using the
4819 /// supplied predicate (which should be used to only accept the types of
4820 /// definitions expected e.g., traits). The lookup spans across all crates.
4822 /// NOTE: The method does not look into imports, but this is not a problem,
4823 /// since we report the definitions (thus, the de-aliased imports).
4824 fn lookup_import_candidates<FilterFn>(&mut self,
4825 lookup_ident: Ident,
4826 namespace: Namespace,
4827 filter_fn: FilterFn)
4828 -> Vec<ImportSuggestion>
4829 where FilterFn: Fn(Def) -> bool
4831 let mut suggestions = self.lookup_import_candidates_from_module(
4832 lookup_ident, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn);
4834 if lookup_ident.span.rust_2018() {
4835 let extern_prelude_names = self.extern_prelude.clone();
4836 for (ident, _) in extern_prelude_names.into_iter() {
4837 if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name,
4839 let crate_root = self.get_module(DefId {
4841 index: CRATE_DEF_INDEX,
4843 self.populate_module_if_necessary(&crate_root);
4845 suggestions.extend(self.lookup_import_candidates_from_module(
4846 lookup_ident, namespace, crate_root, ident, &filter_fn));
4854 fn find_module(&mut self,
4856 -> Option<(Module<'a>, ImportSuggestion)>
4858 let mut result = None;
4859 let mut seen_modules = FxHashSet::default();
4860 let mut worklist = vec![(self.graph_root, Vec::new())];
4862 while let Some((in_module, path_segments)) = worklist.pop() {
4863 // abort if the module is already found
4864 if result.is_some() { break; }
4866 self.populate_module_if_necessary(in_module);
4868 in_module.for_each_child_stable(|ident, _, name_binding| {
4869 // abort if the module is already found or if name_binding is private external
4870 if result.is_some() || !name_binding.vis.is_visible_locally() {
4873 if let Some(module) = name_binding.module() {
4875 let mut path_segments = path_segments.clone();
4876 path_segments.push(ast::PathSegment::from_ident(ident));
4877 if module.def() == Some(module_def) {
4879 span: name_binding.span,
4880 segments: path_segments,
4882 result = Some((module, ImportSuggestion { path }));
4884 // add the module to the lookup
4885 if seen_modules.insert(module.def_id().unwrap()) {
4886 worklist.push((module, path_segments));
4896 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4897 if let Def::Enum(..) = enum_def {} else {
4898 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4901 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4902 self.populate_module_if_necessary(enum_module);
4904 let mut variants = Vec::new();
4905 enum_module.for_each_child_stable(|ident, _, name_binding| {
4906 if let Def::Variant(..) = name_binding.def() {
4907 let mut segms = enum_import_suggestion.path.segments.clone();
4908 segms.push(ast::PathSegment::from_ident(ident));
4909 variants.push(Path {
4910 span: name_binding.span,
4919 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4920 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4921 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4922 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4926 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4928 ast::VisibilityKind::Public => ty::Visibility::Public,
4929 ast::VisibilityKind::Crate(..) => {
4930 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4932 ast::VisibilityKind::Inherited => {
4933 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4935 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4936 // For visibilities we are not ready to provide correct implementation of "uniform
4937 // paths" right now, so on 2018 edition we only allow module-relative paths for now.
4938 // On 2015 edition visibilities are resolved as crate-relative by default,
4939 // so we are prepending a root segment if necessary.
4940 let ident = path.segments.get(0).expect("empty path in visibility").ident;
4941 let crate_root = if ident.is_path_segment_keyword() {
4943 } else if ident.span.rust_2018() {
4944 let msg = "relative paths are not supported in visibilities on 2018 edition";
4945 self.session.struct_span_err(ident.span, msg)
4949 format!("crate::{}", path),
4950 Applicability::MaybeIncorrect,
4953 return ty::Visibility::Public;
4955 let ctxt = ident.span.ctxt();
4956 Some(Segment::from_ident(Ident::new(
4957 keywords::PathRoot.name(), path.span.shrink_to_lo().with_ctxt(ctxt)
4961 let segments = crate_root.into_iter()
4962 .chain(path.segments.iter().map(|seg| seg.into())).collect::<Vec<_>>();
4963 let def = self.smart_resolve_path_fragment(
4968 PathSource::Visibility,
4969 CrateLint::SimplePath(id),
4971 if def == Def::Err {
4972 ty::Visibility::Public
4974 let vis = ty::Visibility::Restricted(def.def_id());
4975 if self.is_accessible(vis) {
4978 self.session.span_err(path.span, "visibilities can only be restricted \
4979 to ancestor modules");
4980 ty::Visibility::Public
4987 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4988 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4991 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4992 vis.is_accessible_from(module.normal_ancestor_id, self)
4995 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
4996 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
4997 if !ptr::eq(module, old_module) {
4998 span_bug!(binding.span, "parent module is reset for binding");
5003 fn disambiguate_legacy_vs_modern(
5005 legacy: &'a NameBinding<'a>,
5006 modern: &'a NameBinding<'a>,
5008 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
5009 // is disambiguated to mitigate regressions from macro modularization.
5010 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
5011 match (self.binding_parent_modules.get(&PtrKey(legacy)),
5012 self.binding_parent_modules.get(&PtrKey(modern))) {
5013 (Some(legacy), Some(modern)) =>
5014 legacy.normal_ancestor_id == modern.normal_ancestor_id &&
5015 modern.is_ancestor_of(legacy),
5020 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
5021 if b.span.is_dummy() {
5022 let add_built_in = match b.def() {
5023 // These already contain the "built-in" prefix or look bad with it.
5024 Def::NonMacroAttr(..) | Def::PrimTy(..) | Def::ToolMod => false,
5027 let (built_in, from) = if from_prelude {
5028 ("", " from prelude")
5029 } else if b.is_extern_crate() && !b.is_import() &&
5030 self.session.opts.externs.get(&ident.as_str()).is_some() {
5031 ("", " passed with `--extern`")
5032 } else if add_built_in {
5038 let article = if built_in.is_empty() { b.article() } else { "a" };
5039 format!("{a}{built_in} {thing}{from}",
5040 a = article, thing = b.descr(), built_in = built_in, from = from)
5042 let introduced = if b.is_import() { "imported" } else { "defined" };
5043 format!("the {thing} {introduced} here",
5044 thing = b.descr(), introduced = introduced)
5048 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
5049 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
5050 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
5051 // We have to print the span-less alternative first, otherwise formatting looks bad.
5052 (b2, b1, misc2, misc1, true)
5054 (b1, b2, misc1, misc2, false)
5057 let mut err = struct_span_err!(self.session, ident.span, E0659,
5058 "`{ident}` is ambiguous ({why})",
5059 ident = ident, why = kind.descr());
5060 err.span_label(ident.span, "ambiguous name");
5062 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
5063 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
5064 let note_msg = format!("`{ident}` could{also} refer to {what}",
5065 ident = ident, also = also, what = what);
5067 let mut help_msgs = Vec::new();
5068 if b.is_glob_import() && (kind == AmbiguityKind::GlobVsGlob ||
5069 kind == AmbiguityKind::GlobVsExpanded ||
5070 kind == AmbiguityKind::GlobVsOuter &&
5071 swapped != also.is_empty()) {
5072 help_msgs.push(format!("consider adding an explicit import of \
5073 `{ident}` to disambiguate", ident = ident))
5075 if b.is_extern_crate() && ident.span.rust_2018() {
5076 help_msgs.push(format!(
5077 "use `::{ident}` to refer to this {thing} unambiguously",
5078 ident = ident, thing = b.descr(),
5081 if misc == AmbiguityErrorMisc::SuggestCrate {
5082 help_msgs.push(format!(
5083 "use `crate::{ident}` to refer to this {thing} unambiguously",
5084 ident = ident, thing = b.descr(),
5086 } else if misc == AmbiguityErrorMisc::SuggestSelf {
5087 help_msgs.push(format!(
5088 "use `self::{ident}` to refer to this {thing} unambiguously",
5089 ident = ident, thing = b.descr(),
5093 err.span_note(b.span, ¬e_msg);
5094 for (i, help_msg) in help_msgs.iter().enumerate() {
5095 let or = if i == 0 { "" } else { "or " };
5096 err.help(&format!("{}{}", or, help_msg));
5100 could_refer_to(b1, misc1, "");
5101 could_refer_to(b2, misc2, " also");
5105 fn report_errors(&mut self, krate: &Crate) {
5106 self.report_with_use_injections(krate);
5108 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
5109 let msg = "macro-expanded `macro_export` macros from the current crate \
5110 cannot be referred to by absolute paths";
5111 self.session.buffer_lint_with_diagnostic(
5112 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
5113 CRATE_NODE_ID, span_use, msg,
5114 lint::builtin::BuiltinLintDiagnostics::
5115 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
5119 for ambiguity_error in &self.ambiguity_errors {
5120 self.report_ambiguity_error(ambiguity_error);
5123 let mut reported_spans = FxHashSet::default();
5124 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
5125 if reported_spans.insert(dedup_span) {
5126 span_err!(self.session, ident.span, E0603, "{} `{}` is private",
5127 binding.descr(), ident.name);
5132 fn report_with_use_injections(&mut self, krate: &Crate) {
5133 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
5134 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
5135 if !candidates.is_empty() {
5136 show_candidates(&mut err, span, &candidates, better, found_use);
5142 fn report_conflict<'b>(&mut self,
5146 new_binding: &NameBinding<'b>,
5147 old_binding: &NameBinding<'b>) {
5148 // Error on the second of two conflicting names
5149 if old_binding.span.lo() > new_binding.span.lo() {
5150 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
5153 let container = match parent.kind {
5154 ModuleKind::Def(Def::Mod(_), _) => "module",
5155 ModuleKind::Def(Def::Trait(_), _) => "trait",
5156 ModuleKind::Block(..) => "block",
5160 let old_noun = match old_binding.is_import() {
5162 false => "definition",
5165 let new_participle = match new_binding.is_import() {
5170 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
5172 if let Some(s) = self.name_already_seen.get(&name) {
5178 let old_kind = match (ns, old_binding.module()) {
5179 (ValueNS, _) => "value",
5180 (MacroNS, _) => "macro",
5181 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
5182 (TypeNS, Some(module)) if module.is_normal() => "module",
5183 (TypeNS, Some(module)) if module.is_trait() => "trait",
5184 (TypeNS, _) => "type",
5187 let msg = format!("the name `{}` is defined multiple times", name);
5189 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
5190 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
5191 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
5192 true => struct_span_err!(self.session, span, E0254, "{}", msg),
5193 false => struct_span_err!(self.session, span, E0260, "{}", msg),
5195 _ => match (old_binding.is_import(), new_binding.is_import()) {
5196 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
5197 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
5198 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
5202 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
5207 err.span_label(span, format!("`{}` re{} here", name, new_participle));
5209 self.session.source_map().def_span(old_binding.span),
5210 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
5213 // See https://github.com/rust-lang/rust/issues/32354
5214 use NameBindingKind::Import;
5215 let directive = match (&new_binding.kind, &old_binding.kind) {
5216 // If there are two imports where one or both have attributes then prefer removing the
5217 // import without attributes.
5218 (Import { directive: new, .. }, Import { directive: old, .. }) if {
5219 !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
5220 (new.has_attributes || old.has_attributes)
5222 if old.has_attributes {
5223 Some((new, new_binding.span, true))
5225 Some((old, old_binding.span, true))
5228 // Otherwise prioritize the new binding.
5229 (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
5230 Some((directive, new_binding.span, other.is_import())),
5231 (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
5232 Some((directive, old_binding.span, other.is_import())),
5236 // Check if the target of the use for both bindings is the same.
5237 let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
5238 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
5239 let from_item = self.extern_prelude.get(&ident)
5240 .map(|entry| entry.introduced_by_item)
5242 // Only suggest removing an import if both bindings are to the same def, if both spans
5243 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
5244 // been introduced by a item.
5245 let should_remove_import = duplicate && !has_dummy_span &&
5246 ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
5249 Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
5250 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
5251 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
5252 // Simple case - remove the entire import. Due to the above match arm, this can
5253 // only be a single use so just remove it entirely.
5254 err.span_suggestion(
5255 directive.use_span_with_attributes,
5256 "remove unnecessary import",
5258 Applicability::MaybeIncorrect,
5261 Some((directive, span, _)) =>
5262 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
5267 self.name_already_seen.insert(name, span);
5270 /// This function adds a suggestion to change the binding name of a new import that conflicts
5271 /// with an existing import.
5273 /// ```ignore (diagnostic)
5274 /// help: you can use `as` to change the binding name of the import
5276 /// LL | use foo::bar as other_bar;
5277 /// | ^^^^^^^^^^^^^^^^^^^^^
5279 fn add_suggestion_for_rename_of_use(
5281 err: &mut DiagnosticBuilder<'_>,
5283 directive: &ImportDirective<'_>,
5286 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
5287 format!("Other{}", name)
5289 format!("other_{}", name)
5292 let mut suggestion = None;
5293 match directive.subclass {
5294 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
5295 suggestion = Some(format!("self as {}", suggested_name)),
5296 ImportDirectiveSubclass::SingleImport { source, .. } => {
5297 if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
5298 .map(|pos| pos as usize) {
5299 if let Ok(snippet) = self.session.source_map()
5300 .span_to_snippet(binding_span) {
5301 if pos <= snippet.len() {
5302 suggestion = Some(format!(
5306 if snippet.ends_with(";") { ";" } else { "" }
5312 ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
5313 suggestion = Some(format!(
5314 "extern crate {} as {};",
5315 source.unwrap_or(target.name),
5318 _ => unreachable!(),
5321 let rename_msg = "you can use `as` to change the binding name of the import";
5322 if let Some(suggestion) = suggestion {
5323 err.span_suggestion(
5327 Applicability::MaybeIncorrect,
5330 err.span_label(binding_span, rename_msg);
5334 /// This function adds a suggestion to remove a unnecessary binding from an import that is
5335 /// nested. In the following example, this function will be invoked to remove the `a` binding
5336 /// in the second use statement:
5338 /// ```ignore (diagnostic)
5339 /// use issue_52891::a;
5340 /// use issue_52891::{d, a, e};
5343 /// The following suggestion will be added:
5345 /// ```ignore (diagnostic)
5346 /// use issue_52891::{d, a, e};
5347 /// ^-- help: remove unnecessary import
5350 /// If the nested use contains only one import then the suggestion will remove the entire
5353 /// It is expected that the directive provided is a nested import - this isn't checked by the
5354 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
5355 /// as characters expected by span manipulations won't be present.
5356 fn add_suggestion_for_duplicate_nested_use(
5358 err: &mut DiagnosticBuilder<'_>,
5359 directive: &ImportDirective<'_>,
5362 assert!(directive.is_nested());
5363 let message = "remove unnecessary import";
5364 let source_map = self.session.source_map();
5366 // Two examples will be used to illustrate the span manipulations we're doing:
5368 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
5369 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
5370 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
5371 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
5373 // Find the span of everything after the binding.
5374 // ie. `a, e};` or `a};`
5375 let binding_until_end = binding_span.with_hi(directive.use_span.hi());
5377 // Find everything after the binding but not including the binding.
5378 // ie. `, e};` or `};`
5379 let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
5381 // Keep characters in the span until we encounter something that isn't a comma or
5385 // Also note whether a closing brace character was encountered. If there
5386 // was, then later go backwards to remove any trailing commas that are left.
5387 let mut found_closing_brace = false;
5388 let after_binding_until_next_binding = source_map.span_take_while(
5389 after_binding_until_end,
5391 if ch == '}' { found_closing_brace = true; }
5392 ch == ' ' || ch == ','
5396 // Combine the two spans.
5397 // ie. `a, ` or `a`.
5399 // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
5400 let span = binding_span.with_hi(after_binding_until_next_binding.hi());
5402 // If there was a closing brace then identify the span to remove any trailing commas from
5403 // previous imports.
5404 if found_closing_brace {
5405 if let Ok(prev_source) = source_map.span_to_prev_source(span) {
5406 // `prev_source` will contain all of the source that came before the span.
5407 // Then split based on a command and take the first (ie. closest to our span)
5408 // snippet. In the example, this is a space.
5409 let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
5410 let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
5411 if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
5412 let prev_comma = prev_comma.first().unwrap();
5413 let prev_starting_brace = prev_starting_brace.first().unwrap();
5415 // If the amount of source code before the comma is greater than
5416 // the amount of source code before the starting brace then we've only
5417 // got one item in the nested item (eg. `issue_52891::{self}`).
5418 if prev_comma.len() > prev_starting_brace.len() {
5419 // So just remove the entire line...
5420 err.span_suggestion(
5421 directive.use_span_with_attributes,
5424 Applicability::MaybeIncorrect,
5429 let span = span.with_lo(BytePos(
5430 // Take away the number of bytes for the characters we've found and an
5431 // extra for the comma.
5432 span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
5434 err.span_suggestion(
5435 span, message, String::new(), Applicability::MaybeIncorrect,
5442 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
5445 fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
5446 -> Option<&'a NameBinding<'a>> {
5447 if ident.is_path_segment_keyword() {
5448 // Make sure `self`, `super` etc produce an error when passed to here.
5451 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
5452 if let Some(binding) = entry.extern_crate_item {
5453 if !speculative && entry.introduced_by_item {
5454 self.record_use(ident, TypeNS, binding, false);
5458 let crate_id = if !speculative {
5459 self.crate_loader.process_path_extern(ident.name, ident.span)
5460 } else if let Some(crate_id) =
5461 self.crate_loader.maybe_process_path_extern(ident.name, ident.span) {
5466 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
5467 self.populate_module_if_necessary(&crate_root);
5468 Some((crate_root, ty::Visibility::Public, DUMMY_SP, Mark::root())
5469 .to_name_binding(self.arenas))
5475 fn is_self_type(path: &[Segment], namespace: Namespace) -> bool {
5476 namespace == TypeNS && path.len() == 1 && path[0].ident.name == keywords::SelfUpper.name()
5479 fn is_self_value(path: &[Segment], namespace: Namespace) -> bool {
5480 namespace == ValueNS && path.len() == 1 && path[0].ident.name == keywords::SelfLower.name()
5483 fn names_to_string(idents: &[Ident]) -> String {
5484 let mut result = String::new();
5485 for (i, ident) in idents.iter()
5486 .filter(|ident| ident.name != keywords::PathRoot.name())
5489 result.push_str("::");
5491 result.push_str(&ident.as_str());
5496 fn path_names_to_string(path: &Path) -> String {
5497 names_to_string(&path.segments.iter()
5498 .map(|seg| seg.ident)
5499 .collect::<Vec<_>>())
5502 /// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
5503 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
5504 let variant_path = &suggestion.path;
5505 let variant_path_string = path_names_to_string(variant_path);
5507 let path_len = suggestion.path.segments.len();
5508 let enum_path = ast::Path {
5509 span: suggestion.path.span,
5510 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
5512 let enum_path_string = path_names_to_string(&enum_path);
5514 (variant_path_string, enum_path_string)
5518 /// When an entity with a given name is not available in scope, we search for
5519 /// entities with that name in all crates. This method allows outputting the
5520 /// results of this search in a programmer-friendly way
5521 fn show_candidates(err: &mut DiagnosticBuilder<'_>,
5522 // This is `None` if all placement locations are inside expansions
5524 candidates: &[ImportSuggestion],
5528 // we want consistent results across executions, but candidates are produced
5529 // by iterating through a hash map, so make sure they are ordered:
5530 let mut path_strings: Vec<_> =
5531 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
5532 path_strings.sort();
5534 let better = if better { "better " } else { "" };
5535 let msg_diff = match path_strings.len() {
5536 1 => " is found in another module, you can import it",
5537 _ => "s are found in other modules, you can import them",
5539 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
5541 if let Some(span) = span {
5542 for candidate in &mut path_strings {
5543 // produce an additional newline to separate the new use statement
5544 // from the directly following item.
5545 let additional_newline = if found_use {
5550 *candidate = format!("use {};\n{}", candidate, additional_newline);
5553 err.span_suggestions(
5556 path_strings.into_iter(),
5557 Applicability::Unspecified,
5562 for candidate in path_strings {
5564 msg.push_str(&candidate);
5569 /// A somewhat inefficient routine to obtain the name of a module.
5570 fn module_to_string(module: Module<'_>) -> Option<String> {
5571 let mut names = Vec::new();
5573 fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
5574 if let ModuleKind::Def(_, name) = module.kind {
5575 if let Some(parent) = module.parent {
5576 names.push(Ident::with_empty_ctxt(name));
5577 collect_mod(names, parent);
5580 // danger, shouldn't be ident?
5581 names.push(Ident::from_str("<opaque>"));
5582 collect_mod(names, module.parent.unwrap());
5585 collect_mod(&mut names, module);
5587 if names.is_empty() {
5590 Some(names_to_string(&names.into_iter()
5592 .collect::<Vec<_>>()))
5595 fn err_path_resolution() -> PathResolution {
5596 PathResolution::new(Def::Err)
5599 #[derive(Copy, Clone, Debug)]
5601 /// Do not issue the lint
5604 /// This lint applies to some random path like `impl ::foo::Bar`
5605 /// or whatever. In this case, we can take the span of that path.
5608 /// This lint comes from a `use` statement. In this case, what we
5609 /// care about really is the *root* `use` statement; e.g., if we
5610 /// have nested things like `use a::{b, c}`, we care about the
5612 UsePath { root_id: NodeId, root_span: Span },
5614 /// This is the "trait item" from a fully qualified path. For example,
5615 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
5616 /// The `path_span` is the span of the to the trait itself (`X::Y`).
5617 QPathTrait { qpath_id: NodeId, qpath_span: Span },
5621 fn node_id(&self) -> Option<NodeId> {
5623 CrateLint::No => None,
5624 CrateLint::SimplePath(id) |
5625 CrateLint::UsePath { root_id: id, .. } |
5626 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
5631 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }