1 // ignore-tidy-filelength
3 //! This crate is responsible for the part of name resolution that doesn't require type checker.
5 //! Module structure of the crate is built here.
6 //! Paths in macros, imports, expressions, types, patterns are resolved here.
7 //! Label and lifetime names are resolved here as well.
9 //! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
12 #![feature(bool_to_option)]
13 #![feature(crate_visibility_modifier)]
15 #![feature(or_patterns)]
16 #![recursion_limit = "256"]
18 pub use rustc_hir::def::{Namespace, PerNS};
22 use rustc_arena::TypedArena;
23 use rustc_ast::ast::{self, FloatTy, IntTy, NodeId, UintTy};
24 use rustc_ast::ast::{Crate, CRATE_NODE_ID};
25 use rustc_ast::ast::{ItemKind, Path};
26 use rustc_ast::node_id::NodeMap;
27 use rustc_ast::unwrap_or;
28 use rustc_ast::visit::{self, Visitor};
29 use rustc_ast_lowering::ResolverAstLowering;
30 use rustc_ast_pretty::pprust;
31 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
32 use rustc_data_structures::ptr_key::PtrKey;
33 use rustc_data_structures::sync::Lrc;
34 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
35 use rustc_expand::base::SyntaxExtension;
36 use rustc_hir::def::Namespace::*;
37 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
38 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
39 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
40 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
41 use rustc_hir::TraitCandidate;
42 use rustc_index::vec::IndexVec;
43 use rustc_metadata::creader::{CStore, CrateLoader};
44 use rustc_middle::hir::exports::ExportMap;
45 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
46 use rustc_middle::span_bug;
47 use rustc_middle::ty::query::Providers;
48 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
49 use rustc_session::lint;
50 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
51 use rustc_session::Session;
52 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
53 use rustc_span::source_map::Spanned;
54 use rustc_span::symbol::{kw, sym, Ident, Symbol};
55 use rustc_span::{Span, DUMMY_SP};
57 use std::cell::{Cell, RefCell};
58 use std::collections::BTreeSet;
59 use std::{cmp, fmt, iter, ptr};
62 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
63 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
64 use imports::{Import, ImportKind, ImportResolver, NameResolution};
65 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
66 use macros::{MacroRulesBinding, MacroRulesScope};
68 type Res = def::Res<NodeId>;
70 mod build_reduced_graph;
83 #[derive(Copy, Clone, PartialEq, Debug)]
84 pub enum Determinacy {
90 fn determined(determined: bool) -> Determinacy {
91 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
95 /// A specific scope in which a name can be looked up.
96 /// This enum is currently used only for early resolution (imports and macros),
97 /// but not for late resolution yet.
98 #[derive(Clone, Copy)]
100 DeriveHelpers(ExpnId),
102 MacroRules(MacroRulesScope<'a>),
114 /// Names from different contexts may want to visit different subsets of all specific scopes
115 /// with different restrictions when looking up the resolution.
116 /// This enum is currently used only for early resolution (imports and macros),
117 /// but not for late resolution yet.
119 /// All scopes with the given namespace.
120 All(Namespace, /*is_import*/ bool),
121 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
122 AbsolutePath(Namespace),
123 /// All scopes with macro namespace and the given macro kind restriction.
127 /// Everything you need to know about a name's location to resolve it.
128 /// Serves as a starting point for the scope visitor.
129 /// This struct is currently used only for early resolution (imports and macros),
130 /// but not for late resolution yet.
131 #[derive(Clone, Copy, Debug)]
132 pub struct ParentScope<'a> {
135 macro_rules: MacroRulesScope<'a>,
136 derives: &'a [ast::Path],
139 impl<'a> ParentScope<'a> {
140 /// Creates a parent scope with the passed argument used as the module scope component,
141 /// and other scope components set to default empty values.
142 pub fn module(module: Module<'a>) -> ParentScope<'a> {
145 expansion: ExpnId::root(),
146 macro_rules: MacroRulesScope::Empty,
153 struct BindingError {
155 origin: BTreeSet<Span>,
156 target: BTreeSet<Span>,
160 impl PartialOrd for BindingError {
161 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
162 Some(self.cmp(other))
166 impl PartialEq for BindingError {
167 fn eq(&self, other: &BindingError) -> bool {
168 self.name == other.name
172 impl Ord for BindingError {
173 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
174 self.name.cmp(&other.name)
178 enum ResolutionError<'a> {
179 /// Error E0401: can't use type or const parameters from outer function.
180 GenericParamsFromOuterFunction(Res, HasGenericParams),
181 /// Error E0403: the name is already used for a type or const parameter in this generic
183 NameAlreadyUsedInParameterList(Symbol, Span),
184 /// Error E0407: method is not a member of trait.
185 MethodNotMemberOfTrait(Symbol, &'a str),
186 /// Error E0437: type is not a member of trait.
187 TypeNotMemberOfTrait(Symbol, &'a str),
188 /// Error E0438: const is not a member of trait.
189 ConstNotMemberOfTrait(Symbol, &'a str),
190 /// Error E0408: variable `{}` is not bound in all patterns.
191 VariableNotBoundInPattern(&'a BindingError),
192 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
193 VariableBoundWithDifferentMode(Symbol, Span),
194 /// Error E0415: identifier is bound more than once in this parameter list.
195 IdentifierBoundMoreThanOnceInParameterList(Symbol),
196 /// Error E0416: identifier is bound more than once in the same pattern.
197 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
198 /// Error E0426: use of undeclared label.
199 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
200 /// Error E0429: `self` imports are only allowed within a `{ }` list.
201 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
202 /// Error E0430: `self` import can only appear once in the list.
203 SelfImportCanOnlyAppearOnceInTheList,
204 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
205 SelfImportOnlyInImportListWithNonEmptyPrefix,
206 /// Error E0433: failed to resolve.
207 FailedToResolve { label: String, suggestion: Option<Suggestion> },
208 /// Error E0434: can't capture dynamic environment in a fn item.
209 CannotCaptureDynamicEnvironmentInFnItem,
210 /// Error E0435: attempt to use a non-constant value in a constant.
211 AttemptToUseNonConstantValueInConstant,
212 /// Error E0530: `X` bindings cannot shadow `Y`s.
213 BindingShadowsSomethingUnacceptable(&'static str, Symbol, &'a NameBinding<'a>),
214 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
215 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
216 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
217 ParamInTyOfConstParam(Symbol),
218 /// constant values inside of type parameter defaults must not depend on generic parameters.
219 ParamInAnonConstInTyDefault(Symbol),
220 /// generic parameters must not be used inside of non trivial constant values.
222 /// This error is only emitted when using `min_const_generics`.
223 ParamInNonTrivialAnonConst(Symbol),
224 /// Error E0735: type parameters with a default cannot use `Self`
225 SelfInTyParamDefault,
226 /// Error E0767: use of unreachable label
227 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
230 enum VisResolutionError<'a> {
231 Relative2018(Span, &'a ast::Path),
233 FailedToResolve(Span, String, Option<Suggestion>),
234 ExpectedFound(Span, String, Res),
239 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
240 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
241 #[derive(Clone, Copy, Debug)]
245 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
246 /// nonsensical suggestions.
247 has_generic_args: bool,
251 fn from_path(path: &Path) -> Vec<Segment> {
252 path.segments.iter().map(|s| s.into()).collect()
255 fn from_ident(ident: Ident) -> Segment {
256 Segment { ident, id: None, has_generic_args: false }
259 fn names_to_string(segments: &[Segment]) -> String {
260 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
264 impl<'a> From<&'a ast::PathSegment> for Segment {
265 fn from(seg: &'a ast::PathSegment) -> Segment {
266 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
270 struct UsePlacementFinder {
271 target_module: NodeId,
276 impl UsePlacementFinder {
277 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
278 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
279 visit::walk_crate(&mut finder, krate);
280 (finder.span, finder.found_use)
284 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
287 module: &'tcx ast::Mod,
289 _: &[ast::Attribute],
292 if self.span.is_some() {
295 if node_id != self.target_module {
296 visit::walk_mod(self, module);
299 // find a use statement
300 for item in &module.items {
302 ItemKind::Use(..) => {
303 // don't suggest placing a use before the prelude
304 // import or other generated ones
305 if !item.span.from_expansion() {
306 self.span = Some(item.span.shrink_to_lo());
307 self.found_use = true;
311 // don't place use before extern crate
312 ItemKind::ExternCrate(_) => {}
313 // but place them before the first other item
315 if self.span.map_or(true, |span| item.span < span) {
316 if !item.span.from_expansion() {
317 // don't insert between attributes and an item
318 if item.attrs.is_empty() {
319 self.span = Some(item.span.shrink_to_lo());
321 // find the first attribute on the item
322 for attr in &item.attrs {
323 if self.span.map_or(true, |span| attr.span < span) {
324 self.span = Some(attr.span.shrink_to_lo());
336 /// An intermediate resolution result.
338 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
339 /// items are visible in their whole block, while `Res`es only from the place they are defined
342 enum LexicalScopeBinding<'a> {
343 Item(&'a NameBinding<'a>),
347 impl<'a> LexicalScopeBinding<'a> {
348 fn res(self) -> Res {
350 LexicalScopeBinding::Item(binding) => binding.res(),
351 LexicalScopeBinding::Res(res) => res,
356 #[derive(Copy, Clone, Debug)]
357 enum ModuleOrUniformRoot<'a> {
361 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
362 CrateRootAndExternPrelude,
364 /// Virtual module that denotes resolution in extern prelude.
365 /// Used for paths starting with `::` on 2018 edition.
368 /// Virtual module that denotes resolution in current scope.
369 /// Used only for resolving single-segment imports. The reason it exists is that import paths
370 /// are always split into two parts, the first of which should be some kind of module.
374 impl ModuleOrUniformRoot<'_> {
375 fn same_def(lhs: Self, rhs: Self) -> bool {
377 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
378 lhs.def_id() == rhs.def_id()
381 ModuleOrUniformRoot::CrateRootAndExternPrelude,
382 ModuleOrUniformRoot::CrateRootAndExternPrelude,
384 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
385 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
391 #[derive(Clone, Debug)]
392 enum PathResult<'a> {
393 Module(ModuleOrUniformRoot<'a>),
394 NonModule(PartialRes),
399 suggestion: Option<Suggestion>,
400 is_error_from_last_segment: bool,
405 /// An anonymous module; e.g., just a block.
410 /// { // This is an anonymous module
411 /// f(); // This resolves to (2) as we are inside the block.
414 /// f(); // Resolves to (1)
418 /// Any module with a name.
422 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
423 /// * A trait or an enum (it implicitly contains associated types, methods and variant
425 Def(DefKind, DefId, Symbol),
429 /// Get name of the module.
430 pub fn name(&self) -> Option<Symbol> {
432 ModuleKind::Block(..) => None,
433 ModuleKind::Def(.., name) => Some(*name),
438 /// A key that identifies a binding in a given `Module`.
440 /// Multiple bindings in the same module can have the same key (in a valid
441 /// program) if all but one of them come from glob imports.
442 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
444 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
448 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
449 /// `_` in the expanded AST that introduced this binding.
453 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
455 /// One node in the tree of modules.
456 pub struct ModuleData<'a> {
457 parent: Option<Module<'a>>,
460 // The def id of the closest normal module (`mod`) ancestor (including this module).
461 normal_ancestor_id: DefId,
463 // Mapping between names and their (possibly in-progress) resolutions in this module.
464 // Resolutions in modules from other crates are not populated until accessed.
465 lazy_resolutions: Resolutions<'a>,
466 // True if this is a module from other crate that needs to be populated on access.
467 populate_on_access: Cell<bool>,
469 // Macro invocations that can expand into items in this module.
470 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
472 no_implicit_prelude: bool,
474 glob_importers: RefCell<Vec<&'a Import<'a>>>,
475 globs: RefCell<Vec<&'a Import<'a>>>,
477 // Used to memoize the traits in this module for faster searches through all traits in scope.
478 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
480 /// Span of the module itself. Used for error reporting.
486 type Module<'a> = &'a ModuleData<'a>;
488 impl<'a> ModuleData<'a> {
490 parent: Option<Module<'a>>,
492 normal_ancestor_id: DefId,
500 lazy_resolutions: Default::default(),
501 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
502 unexpanded_invocations: Default::default(),
503 no_implicit_prelude: false,
504 glob_importers: RefCell::new(Vec::new()),
505 globs: RefCell::new(Vec::new()),
506 traits: RefCell::new(None),
512 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
514 R: AsMut<Resolver<'a>>,
515 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
517 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
518 if let Some(binding) = name_resolution.borrow().binding {
519 f(resolver, key.ident, key.ns, binding);
524 fn res(&self) -> Option<Res> {
526 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
531 fn def_id(&self) -> Option<DefId> {
533 ModuleKind::Def(_, def_id, _) => Some(def_id),
538 // `self` resolves to the first module ancestor that `is_normal`.
539 fn is_normal(&self) -> bool {
541 ModuleKind::Def(DefKind::Mod, _, _) => true,
546 fn is_trait(&self) -> bool {
548 ModuleKind::Def(DefKind::Trait, _, _) => true,
553 fn nearest_item_scope(&'a self) -> Module<'a> {
555 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
556 self.parent.expect("enum or trait module without a parent")
562 fn is_ancestor_of(&self, mut other: &Self) -> bool {
563 while !ptr::eq(self, other) {
564 if let Some(parent) = other.parent {
574 impl<'a> fmt::Debug for ModuleData<'a> {
575 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
576 write!(f, "{:?}", self.res())
580 /// Records a possibly-private value, type, or module definition.
581 #[derive(Clone, Debug)]
582 pub struct NameBinding<'a> {
583 kind: NameBindingKind<'a>,
584 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
590 pub trait ToNameBinding<'a> {
591 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
594 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
595 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
600 #[derive(Clone, Debug)]
601 enum NameBindingKind<'a> {
602 Res(Res, /* is_macro_export */ bool),
604 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
607 impl<'a> NameBindingKind<'a> {
608 /// Is this a name binding of a import?
609 fn is_import(&self) -> bool {
611 NameBindingKind::Import { .. } => true,
617 struct PrivacyError<'a> {
619 binding: &'a NameBinding<'a>,
623 struct UseError<'a> {
624 err: DiagnosticBuilder<'a>,
625 /// Candidates which user could `use` to access the missing type.
626 candidates: Vec<ImportSuggestion>,
627 /// The `DefId` of the module to place the use-statements in.
629 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
631 /// Extra free-form suggestion.
632 suggestion: Option<(Span, &'static str, String, Applicability)>,
635 #[derive(Clone, Copy, PartialEq, Debug)]
640 MacroRulesVsModularized,
648 fn descr(self) -> &'static str {
650 AmbiguityKind::Import => "name vs any other name during import resolution",
651 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
652 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
653 AmbiguityKind::MacroRulesVsModularized => {
654 "`macro_rules` vs non-`macro_rules` from other module"
656 AmbiguityKind::GlobVsOuter => {
657 "glob import vs any other name from outer scope during import/macro resolution"
659 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
660 AmbiguityKind::GlobVsExpanded => {
661 "glob import vs macro-expanded name in the same \
662 module during import/macro resolution"
664 AmbiguityKind::MoreExpandedVsOuter => {
665 "macro-expanded name vs less macro-expanded name \
666 from outer scope during import/macro resolution"
672 /// Miscellaneous bits of metadata for better ambiguity error reporting.
673 #[derive(Clone, Copy, PartialEq)]
674 enum AmbiguityErrorMisc {
681 struct AmbiguityError<'a> {
684 b1: &'a NameBinding<'a>,
685 b2: &'a NameBinding<'a>,
686 misc1: AmbiguityErrorMisc,
687 misc2: AmbiguityErrorMisc,
690 impl<'a> NameBinding<'a> {
691 fn module(&self) -> Option<Module<'a>> {
693 NameBindingKind::Module(module) => Some(module),
694 NameBindingKind::Import { binding, .. } => binding.module(),
699 fn res(&self) -> Res {
701 NameBindingKind::Res(res, _) => res,
702 NameBindingKind::Module(module) => module.res().unwrap(),
703 NameBindingKind::Import { binding, .. } => binding.res(),
707 fn is_ambiguity(&self) -> bool {
708 self.ambiguity.is_some()
710 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
715 fn is_possibly_imported_variant(&self) -> bool {
717 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
718 _ => self.is_variant(),
722 // We sometimes need to treat variants as `pub` for backwards compatibility.
723 fn pseudo_vis(&self) -> ty::Visibility {
724 if self.is_variant() && self.res().def_id().is_local() {
725 ty::Visibility::Public
731 fn is_variant(&self) -> bool {
733 NameBindingKind::Res(
734 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
741 fn is_extern_crate(&self) -> bool {
743 NameBindingKind::Import {
744 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
747 NameBindingKind::Module(&ModuleData {
748 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
750 }) => def_id.index == CRATE_DEF_INDEX,
755 fn is_import(&self) -> bool {
757 NameBindingKind::Import { .. } => true,
762 fn is_glob_import(&self) -> bool {
764 NameBindingKind::Import { import, .. } => import.is_glob(),
769 fn is_importable(&self) -> bool {
771 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _) => false,
776 fn is_macro_def(&self) -> bool {
778 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
783 fn macro_kind(&self) -> Option<MacroKind> {
784 self.res().macro_kind()
787 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
788 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
789 // Then this function returns `true` if `self` may emerge from a macro *after* that
790 // in some later round and screw up our previously found resolution.
791 // See more detailed explanation in
792 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
793 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
794 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
795 // Expansions are partially ordered, so "may appear after" is an inversion of
796 // "certainly appears before or simultaneously" and includes unordered cases.
797 let self_parent_expansion = self.expansion;
798 let other_parent_expansion = binding.expansion;
799 let certainly_before_other_or_simultaneously =
800 other_parent_expansion.is_descendant_of(self_parent_expansion);
801 let certainly_before_invoc_or_simultaneously =
802 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
803 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
807 /// Interns the names of the primitive types.
809 /// All other types are defined somewhere and possibly imported, but the primitive ones need
810 /// special handling, since they have no place of origin.
811 struct PrimitiveTypeTable {
812 primitive_types: FxHashMap<Symbol, PrimTy>,
815 impl PrimitiveTypeTable {
816 fn new() -> PrimitiveTypeTable {
817 let mut table = FxHashMap::default();
819 table.insert(sym::bool, Bool);
820 table.insert(sym::char, Char);
821 table.insert(sym::f32, Float(FloatTy::F32));
822 table.insert(sym::f64, Float(FloatTy::F64));
823 table.insert(sym::isize, Int(IntTy::Isize));
824 table.insert(sym::i8, Int(IntTy::I8));
825 table.insert(sym::i16, Int(IntTy::I16));
826 table.insert(sym::i32, Int(IntTy::I32));
827 table.insert(sym::i64, Int(IntTy::I64));
828 table.insert(sym::i128, Int(IntTy::I128));
829 table.insert(sym::str, Str);
830 table.insert(sym::usize, Uint(UintTy::Usize));
831 table.insert(sym::u8, Uint(UintTy::U8));
832 table.insert(sym::u16, Uint(UintTy::U16));
833 table.insert(sym::u32, Uint(UintTy::U32));
834 table.insert(sym::u64, Uint(UintTy::U64));
835 table.insert(sym::u128, Uint(UintTy::U128));
836 Self { primitive_types: table }
840 #[derive(Debug, Default, Clone)]
841 pub struct ExternPreludeEntry<'a> {
842 extern_crate_item: Option<&'a NameBinding<'a>>,
843 pub introduced_by_item: bool,
846 /// The main resolver class.
848 /// This is the visitor that walks the whole crate.
849 pub struct Resolver<'a> {
850 session: &'a Session,
852 definitions: Definitions,
854 graph_root: Module<'a>,
856 prelude: Option<Module<'a>>,
857 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
859 /// N.B., this is used only for better diagnostics, not name resolution itself.
860 has_self: FxHashSet<DefId>,
862 /// Names of fields of an item `DefId` accessible with dot syntax.
863 /// Used for hints during error reporting.
864 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
866 /// All imports known to succeed or fail.
867 determined_imports: Vec<&'a Import<'a>>,
869 /// All non-determined imports.
870 indeterminate_imports: Vec<&'a Import<'a>>,
872 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
873 /// We are resolving a last import segment during import validation.
874 last_import_segment: bool,
875 /// This binding should be ignored during in-module resolution, so that we don't get
876 /// "self-confirming" import resolutions during import validation.
877 unusable_binding: Option<&'a NameBinding<'a>>,
879 /// The idents for the primitive types.
880 primitive_type_table: PrimitiveTypeTable,
882 /// Resolutions for nodes that have a single resolution.
883 partial_res_map: NodeMap<PartialRes>,
884 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
885 import_res_map: NodeMap<PerNS<Option<Res>>>,
886 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
887 label_res_map: NodeMap<NodeId>,
889 /// `CrateNum` resolutions of `extern crate` items.
890 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
891 export_map: ExportMap<LocalDefId>,
892 trait_map: NodeMap<Vec<TraitCandidate>>,
894 /// A map from nodes to anonymous modules.
895 /// Anonymous modules are pseudo-modules that are implicitly created around items
896 /// contained within blocks.
898 /// For example, if we have this:
906 /// There will be an anonymous module created around `g` with the ID of the
907 /// entry block for `f`.
908 block_map: NodeMap<Module<'a>>,
909 /// A fake module that contains no definition and no prelude. Used so that
910 /// some AST passes can generate identifiers that only resolve to local or
912 empty_module: Module<'a>,
913 module_map: FxHashMap<LocalDefId, Module<'a>>,
914 extern_module_map: FxHashMap<DefId, Module<'a>>,
915 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
916 underscore_disambiguator: u32,
918 /// Maps glob imports to the names of items actually imported.
919 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
921 used_imports: FxHashSet<(NodeId, Namespace)>,
922 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
923 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
925 /// Privacy errors are delayed until the end in order to deduplicate them.
926 privacy_errors: Vec<PrivacyError<'a>>,
927 /// Ambiguity errors are delayed for deduplication.
928 ambiguity_errors: Vec<AmbiguityError<'a>>,
929 /// `use` injections are delayed for better placement and deduplication.
930 use_injections: Vec<UseError<'a>>,
931 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
932 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
934 arenas: &'a ResolverArenas<'a>,
935 dummy_binding: &'a NameBinding<'a>,
937 crate_loader: CrateLoader<'a>,
938 macro_names: FxHashSet<Ident>,
939 builtin_macros: FxHashMap<Symbol, SyntaxExtension>,
940 registered_attrs: FxHashSet<Ident>,
941 registered_tools: FxHashSet<Ident>,
942 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
943 all_macros: FxHashMap<Symbol, Res>,
944 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
945 dummy_ext_bang: Lrc<SyntaxExtension>,
946 dummy_ext_derive: Lrc<SyntaxExtension>,
947 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
948 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
949 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
950 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
951 proc_macro_stubs: FxHashSet<LocalDefId>,
952 /// Traces collected during macro resolution and validated when it's complete.
953 single_segment_macro_resolutions:
954 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
955 multi_segment_macro_resolutions:
956 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
957 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
958 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
959 /// Derive macros cannot modify the item themselves and have to store the markers in the global
960 /// context, so they attach the markers to derive container IDs using this resolver table.
961 containers_deriving_copy: FxHashSet<ExpnId>,
962 /// Parent scopes in which the macros were invoked.
963 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
964 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
965 /// `macro_rules` scopes *produced* by expanding the macro invocations,
966 /// include all the `macro_rules` items and other invocations generated by them.
967 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScope<'a>>,
968 /// Helper attributes that are in scope for the given expansion.
969 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
971 /// Avoid duplicated errors for "name already defined".
972 name_already_seen: FxHashMap<Symbol, Span>,
974 potentially_unused_imports: Vec<&'a Import<'a>>,
976 /// Table for mapping struct IDs into struct constructor IDs,
977 /// it's not used during normal resolution, only for better error reporting.
978 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
980 /// Features enabled for this crate.
981 active_features: FxHashSet<Symbol>,
983 /// Stores enum visibilities to properly build a reduced graph
984 /// when visiting the correspondent variants.
985 variant_vis: DefIdMap<ty::Visibility>,
987 lint_buffer: LintBuffer,
989 next_node_id: NodeId,
991 def_id_to_span: IndexVec<LocalDefId, Span>,
993 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
994 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
996 /// Indices of unnamed struct or variant fields with unresolved attributes.
997 placeholder_field_indices: FxHashMap<NodeId, usize>,
998 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
999 /// we know what parent node that fragment should be attached to thanks to this table.
1000 invocation_parents: FxHashMap<ExpnId, LocalDefId>,
1002 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1005 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1007 pub struct ResolverArenas<'a> {
1008 modules: TypedArena<ModuleData<'a>>,
1009 local_modules: RefCell<Vec<Module<'a>>>,
1010 name_bindings: TypedArena<NameBinding<'a>>,
1011 imports: TypedArena<Import<'a>>,
1012 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1013 macro_rules_bindings: TypedArena<MacroRulesBinding<'a>>,
1014 ast_paths: TypedArena<ast::Path>,
1017 impl<'a> ResolverArenas<'a> {
1018 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1019 let module = self.modules.alloc(module);
1020 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1021 self.local_modules.borrow_mut().push(module);
1025 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1026 self.local_modules.borrow()
1028 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1029 self.name_bindings.alloc(name_binding)
1031 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1032 self.imports.alloc(import)
1034 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1035 self.name_resolutions.alloc(Default::default())
1037 fn alloc_macro_rules_binding(
1039 binding: MacroRulesBinding<'a>,
1040 ) -> &'a MacroRulesBinding<'a> {
1041 self.macro_rules_bindings.alloc(binding)
1043 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1044 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1048 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1049 fn as_mut(&mut self) -> &mut Resolver<'a> {
1054 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1055 fn parent(self, id: DefId) -> Option<DefId> {
1056 match id.as_local() {
1057 Some(id) => self.definitions.def_key(id).parent,
1058 None => self.cstore().def_key(id).parent,
1060 .map(|index| DefId { index, ..id })
1064 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1065 /// the resolver is no longer needed as all the relevant information is inline.
1066 impl ResolverAstLowering for Resolver<'_> {
1067 fn def_key(&mut self, id: DefId) -> DefKey {
1068 if let Some(id) = id.as_local() {
1069 self.definitions().def_key(id)
1071 self.cstore().def_key(id)
1075 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1076 self.cstore().item_generics_num_lifetimes(def_id, sess)
1079 fn resolve_str_path(
1082 crate_root: Option<Symbol>,
1083 components: &[Symbol],
1085 ) -> (ast::Path, Res) {
1086 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1087 let segments = iter::once(Ident::with_dummy_span(root))
1091 .chain(components.iter().cloned())
1092 .map(Ident::with_dummy_span),
1094 .map(|i| self.new_ast_path_segment(i))
1095 .collect::<Vec<_>>();
1097 let path = ast::Path { span, segments };
1099 let parent_scope = &ParentScope::module(self.graph_root);
1100 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1102 Err((span, error)) => {
1103 self.report_error(span, error);
1110 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1111 self.partial_res_map.get(&id).cloned()
1114 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1115 self.import_res_map.get(&id).cloned().unwrap_or_default()
1118 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1119 self.label_res_map.get(&id).cloned()
1122 fn definitions(&mut self) -> &mut Definitions {
1123 &mut self.definitions
1126 fn lint_buffer(&mut self) -> &mut LintBuffer {
1127 &mut self.lint_buffer
1130 fn next_node_id(&mut self) -> NodeId {
1134 fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
1138 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1139 self.node_id_to_def_id.get(&node).copied()
1142 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1143 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1146 /// Adds a definition with a parent definition.
1150 node_id: ast::NodeId,
1156 !self.node_id_to_def_id.contains_key(&node_id),
1157 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1160 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1163 // Find the next free disambiguator for this key.
1164 let next_disambiguator = &mut self.next_disambiguator;
1165 let next_disambiguator = |parent, data| {
1166 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1167 let disambiguator = *next_disamb;
1168 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1172 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1174 assert_eq!(self.def_id_to_span.push(span), def_id);
1176 // Some things for which we allocate `LocalDefId`s don't correspond to
1177 // anything in the AST, so they don't have a `NodeId`. For these cases
1178 // we don't need a mapping from `NodeId` to `LocalDefId`.
1179 if node_id != ast::DUMMY_NODE_ID {
1180 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1181 self.node_id_to_def_id.insert(node_id, def_id);
1183 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1189 impl<'a> Resolver<'a> {
1191 session: &'a Session,
1194 metadata_loader: &'a MetadataLoaderDyn,
1195 arenas: &'a ResolverArenas<'a>,
1197 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1198 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1199 let graph_root = arenas.alloc_module(ModuleData {
1200 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1201 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1203 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1204 let empty_module = arenas.alloc_module(ModuleData {
1205 no_implicit_prelude: true,
1214 let mut module_map = FxHashMap::default();
1215 module_map.insert(LocalDefId { local_def_index: CRATE_DEF_INDEX }, graph_root);
1217 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1218 let root = definitions.get_root_def();
1220 let mut def_id_to_span = IndexVec::default();
1221 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1222 let mut def_id_to_node_id = IndexVec::default();
1223 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1224 let mut node_id_to_def_id = FxHashMap::default();
1225 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1227 let mut invocation_parents = FxHashMap::default();
1228 invocation_parents.insert(ExpnId::root(), root);
1230 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1234 .filter(|(_, entry)| entry.add_prelude)
1235 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1238 if !session.contains_name(&krate.attrs, sym::no_core) {
1239 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1240 if !session.contains_name(&krate.attrs, sym::no_std) {
1241 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1242 if session.rust_2018() {
1243 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1248 let (registered_attrs, registered_tools) =
1249 macros::registered_attrs_and_tools(session, &krate.attrs);
1251 let mut invocation_parent_scopes = FxHashMap::default();
1252 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1254 let features = session.features_untracked();
1255 let non_macro_attr =
1256 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1263 // The outermost module has def ID 0; this is not reflected in the
1269 has_self: FxHashSet::default(),
1270 field_names: FxHashMap::default(),
1272 determined_imports: Vec::new(),
1273 indeterminate_imports: Vec::new(),
1275 last_import_segment: false,
1276 unusable_binding: None,
1278 primitive_type_table: PrimitiveTypeTable::new(),
1280 partial_res_map: Default::default(),
1281 import_res_map: Default::default(),
1282 label_res_map: Default::default(),
1283 extern_crate_map: Default::default(),
1284 export_map: FxHashMap::default(),
1285 trait_map: Default::default(),
1286 underscore_disambiguator: 0,
1289 block_map: Default::default(),
1290 extern_module_map: FxHashMap::default(),
1291 binding_parent_modules: FxHashMap::default(),
1292 ast_transform_scopes: FxHashMap::default(),
1294 glob_map: Default::default(),
1296 used_imports: FxHashSet::default(),
1297 maybe_unused_trait_imports: Default::default(),
1298 maybe_unused_extern_crates: Vec::new(),
1300 privacy_errors: Vec::new(),
1301 ambiguity_errors: Vec::new(),
1302 use_injections: Vec::new(),
1303 macro_expanded_macro_export_errors: BTreeSet::new(),
1306 dummy_binding: arenas.alloc_name_binding(NameBinding {
1307 kind: NameBindingKind::Res(Res::Err, false),
1309 expansion: ExpnId::root(),
1311 vis: ty::Visibility::Public,
1314 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1315 macro_names: FxHashSet::default(),
1316 builtin_macros: Default::default(),
1319 macro_use_prelude: FxHashMap::default(),
1320 all_macros: FxHashMap::default(),
1321 macro_map: FxHashMap::default(),
1322 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1323 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1324 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1325 invocation_parent_scopes,
1326 output_macro_rules_scopes: Default::default(),
1327 helper_attrs: Default::default(),
1328 local_macro_def_scopes: FxHashMap::default(),
1329 name_already_seen: FxHashMap::default(),
1330 potentially_unused_imports: Vec::new(),
1331 struct_constructors: Default::default(),
1332 unused_macros: Default::default(),
1333 proc_macro_stubs: Default::default(),
1334 single_segment_macro_resolutions: Default::default(),
1335 multi_segment_macro_resolutions: Default::default(),
1336 builtin_attrs: Default::default(),
1337 containers_deriving_copy: Default::default(),
1338 active_features: features
1339 .declared_lib_features
1341 .map(|(feat, ..)| *feat)
1342 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1344 variant_vis: Default::default(),
1345 lint_buffer: LintBuffer::default(),
1346 next_node_id: NodeId::from_u32(1),
1350 placeholder_field_indices: Default::default(),
1352 next_disambiguator: Default::default(),
1356 pub fn next_node_id(&mut self) -> NodeId {
1361 .expect("input too large; ran out of NodeIds");
1362 self.next_node_id = ast::NodeId::from_usize(next);
1366 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1367 &mut self.lint_buffer
1370 pub fn arenas() -> ResolverArenas<'a> {
1374 pub fn into_outputs(self) -> ResolverOutputs {
1375 let definitions = self.definitions;
1376 let extern_crate_map = self.extern_crate_map;
1377 let export_map = self.export_map;
1378 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1379 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1380 let glob_map = self.glob_map;
1382 definitions: definitions,
1383 cstore: Box::new(self.crate_loader.into_cstore()),
1387 maybe_unused_trait_imports,
1388 maybe_unused_extern_crates,
1389 extern_prelude: self
1392 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1397 pub fn clone_outputs(&self) -> ResolverOutputs {
1399 definitions: self.definitions.clone(),
1400 cstore: Box::new(self.cstore().clone()),
1401 extern_crate_map: self.extern_crate_map.clone(),
1402 export_map: self.export_map.clone(),
1403 glob_map: self.glob_map.clone(),
1404 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1405 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1406 extern_prelude: self
1409 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1414 pub fn cstore(&self) -> &CStore {
1415 self.crate_loader.cstore()
1418 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1419 self.non_macro_attrs[mark_used as usize].clone()
1422 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1424 MacroKind::Bang => self.dummy_ext_bang.clone(),
1425 MacroKind::Derive => self.dummy_ext_derive.clone(),
1426 MacroKind::Attr => self.non_macro_attr(true),
1430 /// Runs the function on each namespace.
1431 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1437 fn is_builtin_macro(&mut self, res: Res) -> bool {
1438 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1441 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1443 match ctxt.outer_expn().expn_data().macro_def_id {
1444 Some(def_id) => return def_id,
1445 None => ctxt.remove_mark(),
1450 /// Entry point to crate resolution.
1451 pub fn resolve_crate(&mut self, krate: &Crate) {
1452 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1454 ImportResolver { r: self }.finalize_imports();
1455 self.finalize_macro_resolutions();
1457 self.late_resolve_crate(krate);
1459 self.check_unused(krate);
1460 self.report_errors(krate);
1461 self.crate_loader.postprocess(krate);
1468 normal_ancestor_id: DefId,
1472 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1473 self.arenas.alloc_module(module)
1476 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1477 let ident = ident.normalize_to_macros_2_0();
1478 let disambiguator = if ident.name == kw::Underscore {
1479 self.underscore_disambiguator += 1;
1480 self.underscore_disambiguator
1484 BindingKey { ident, ns, disambiguator }
1487 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1488 if module.populate_on_access.get() {
1489 module.populate_on_access.set(false);
1490 self.build_reduced_graph_external(module);
1492 &module.lazy_resolutions
1499 ) -> &'a RefCell<NameResolution<'a>> {
1501 .resolutions(module)
1504 .or_insert_with(|| self.arenas.alloc_name_resolution())
1511 used_binding: &'a NameBinding<'a>,
1512 is_lexical_scope: bool,
1514 if let Some((b2, kind)) = used_binding.ambiguity {
1515 self.ambiguity_errors.push(AmbiguityError {
1520 misc1: AmbiguityErrorMisc::None,
1521 misc2: AmbiguityErrorMisc::None,
1524 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1525 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1526 // but not introduce it, as used if they are accessed from lexical scope.
1527 if is_lexical_scope {
1528 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1529 if let Some(crate_item) = entry.extern_crate_item {
1530 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1537 import.used.set(true);
1538 self.used_imports.insert((import.id, ns));
1539 self.add_to_glob_map(&import, ident);
1540 self.record_use(ident, ns, binding, false);
1545 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1546 if import.is_glob() {
1547 let def_id = self.local_def_id(import.id);
1548 self.glob_map.entry(def_id).or_default().insert(ident.name);
1552 /// A generic scope visitor.
1553 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1554 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1557 scope_set: ScopeSet,
1558 parent_scope: &ParentScope<'a>,
1560 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1562 // General principles:
1563 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1564 // built into the language or standard library. This way we can add new names into the
1565 // language or standard library without breaking user code.
1566 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1567 // Places to search (in order of decreasing priority):
1569 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1570 // (open set, not controlled).
1571 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1572 // (open, not controlled).
1573 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1574 // 4. Tool modules (closed, controlled right now, but not in the future).
1575 // 5. Standard library prelude (de-facto closed, controlled).
1576 // 6. Language prelude (closed, controlled).
1578 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1579 // (open set, not controlled).
1580 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1581 // (open, not controlled).
1582 // 3. Standard library prelude (de-facto closed, controlled).
1584 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1585 // are currently reported as errors. They should be higher in priority than preludes
1586 // and probably even names in modules according to the "general principles" above. They
1587 // also should be subject to restricted shadowing because are effectively produced by
1588 // derives (you need to resolve the derive first to add helpers into scope), but they
1589 // should be available before the derive is expanded for compatibility.
1590 // It's mess in general, so we are being conservative for now.
1591 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1592 // priority than prelude macros, but create ambiguities with macros in modules.
1593 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1594 // (open, not controlled). Have higher priority than prelude macros, but create
1595 // ambiguities with `macro_rules`.
1596 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1597 // 4a. User-defined prelude from macro-use
1598 // (open, the open part is from macro expansions, not controlled).
1599 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1600 // 4c. Standard library prelude (de-facto closed, controlled).
1601 // 6. Language prelude: builtin attributes (closed, controlled).
1603 let rust_2015 = ident.span.rust_2015();
1604 let (ns, macro_kind, is_absolute_path) = match scope_set {
1605 ScopeSet::All(ns, _) => (ns, None, false),
1606 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1607 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1609 // Jump out of trait or enum modules, they do not act as scopes.
1610 let module = parent_scope.module.nearest_item_scope();
1611 let mut scope = match ns {
1612 _ if is_absolute_path => Scope::CrateRoot,
1613 TypeNS | ValueNS => Scope::Module(module),
1614 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1616 let mut ident = ident.normalize_to_macros_2_0();
1617 let mut use_prelude = !module.no_implicit_prelude;
1620 let visit = match scope {
1621 // Derive helpers are not in scope when resolving derives in the same container.
1622 Scope::DeriveHelpers(expn_id) => {
1623 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1625 Scope::DeriveHelpersCompat => true,
1626 Scope::MacroRules(..) => true,
1627 Scope::CrateRoot => true,
1628 Scope::Module(..) => true,
1629 Scope::RegisteredAttrs => use_prelude,
1630 Scope::MacroUsePrelude => use_prelude || rust_2015,
1631 Scope::BuiltinAttrs => true,
1632 Scope::ExternPrelude => use_prelude || is_absolute_path,
1633 Scope::ToolPrelude => use_prelude,
1634 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1635 Scope::BuiltinTypes => true,
1639 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1640 return break_result;
1644 scope = match scope {
1645 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1646 // Derive helpers are not visible to code generated by bang or derive macros.
1647 let expn_data = expn_id.expn_data();
1648 match expn_data.kind {
1650 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1651 Scope::DeriveHelpersCompat
1653 _ => Scope::DeriveHelpers(expn_data.parent),
1656 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1657 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1658 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
1659 MacroRulesScope::Binding(binding) => {
1660 Scope::MacroRules(binding.parent_macro_rules_scope)
1662 MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
1663 self.output_macro_rules_scopes
1666 .unwrap_or(self.invocation_parent_scopes[&invoc_id].macro_rules),
1668 MacroRulesScope::Empty => Scope::Module(module),
1670 Scope::CrateRoot => match ns {
1672 ident.span.adjust(ExpnId::root());
1673 Scope::ExternPrelude
1675 ValueNS | MacroNS => break,
1677 Scope::Module(module) => {
1678 use_prelude = !module.no_implicit_prelude;
1679 match self.hygienic_lexical_parent(module, &mut ident.span) {
1680 Some(parent_module) => Scope::Module(parent_module),
1682 ident.span.adjust(ExpnId::root());
1684 TypeNS => Scope::ExternPrelude,
1685 ValueNS => Scope::StdLibPrelude,
1686 MacroNS => Scope::RegisteredAttrs,
1691 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1692 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1693 Scope::BuiltinAttrs => break, // nowhere else to search
1694 Scope::ExternPrelude if is_absolute_path => break,
1695 Scope::ExternPrelude => Scope::ToolPrelude,
1696 Scope::ToolPrelude => Scope::StdLibPrelude,
1697 Scope::StdLibPrelude => match ns {
1698 TypeNS => Scope::BuiltinTypes,
1699 ValueNS => break, // nowhere else to search
1700 MacroNS => Scope::BuiltinAttrs,
1702 Scope::BuiltinTypes => break, // nowhere else to search
1709 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1710 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1711 /// `ident` in the first scope that defines it (or None if no scopes define it).
1713 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1714 /// the items are defined in the block. For example,
1717 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1720 /// g(); // This resolves to the local variable `g` since it shadows the item.
1724 /// Invariant: This must only be called during main resolution, not during
1725 /// import resolution.
1726 fn resolve_ident_in_lexical_scope(
1730 parent_scope: &ParentScope<'a>,
1731 record_used_id: Option<NodeId>,
1734 ) -> Option<LexicalScopeBinding<'a>> {
1735 assert!(ns == TypeNS || ns == ValueNS);
1736 if ident.name == kw::Invalid {
1737 return Some(LexicalScopeBinding::Res(Res::Err));
1739 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1740 // FIXME(jseyfried) improve `Self` hygiene
1741 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1742 (empty_span, empty_span)
1743 } else if ns == TypeNS {
1744 let normalized_span = ident.span.normalize_to_macros_2_0();
1745 (normalized_span, normalized_span)
1747 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1749 ident.span = general_span;
1750 let normalized_ident = Ident { span: normalized_span, ..ident };
1752 // Walk backwards up the ribs in scope.
1753 let record_used = record_used_id.is_some();
1754 let mut module = self.graph_root;
1755 for i in (0..ribs.len()).rev() {
1756 debug!("walk rib\n{:?}", ribs[i].bindings);
1757 // Use the rib kind to determine whether we are resolving parameters
1758 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1759 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1760 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1761 // The ident resolves to a type parameter or local variable.
1762 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1772 module = match ribs[i].kind {
1773 ModuleRibKind(module) => module,
1774 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1775 // If an invocation of this macro created `ident`, give up on `ident`
1776 // and switch to `ident`'s source from the macro definition.
1777 ident.span.remove_mark();
1783 let item = self.resolve_ident_in_module_unadjusted(
1784 ModuleOrUniformRoot::Module(module),
1791 if let Ok(binding) = item {
1792 // The ident resolves to an item.
1793 return Some(LexicalScopeBinding::Item(binding));
1797 ModuleKind::Block(..) => {} // We can see through blocks
1802 ident = normalized_ident;
1803 let mut poisoned = None;
1805 let opt_module = if let Some(node_id) = record_used_id {
1806 self.hygienic_lexical_parent_with_compatibility_fallback(
1813 self.hygienic_lexical_parent(module, &mut ident.span)
1815 module = unwrap_or!(opt_module, break);
1816 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1817 let result = self.resolve_ident_in_module_unadjusted(
1818 ModuleOrUniformRoot::Module(module),
1821 adjusted_parent_scope,
1828 if let Some(node_id) = poisoned {
1829 self.lint_buffer.buffer_lint_with_diagnostic(
1830 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1833 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1834 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1837 return Some(LexicalScopeBinding::Item(binding));
1839 Err(Determined) => continue,
1840 Err(Undetermined) => {
1841 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1846 if !module.no_implicit_prelude {
1847 ident.span.adjust(ExpnId::root());
1849 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1850 return Some(LexicalScopeBinding::Item(binding));
1852 if let Some(ident) = self.registered_tools.get(&ident) {
1854 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1855 .to_name_binding(self.arenas);
1856 return Some(LexicalScopeBinding::Item(binding));
1859 if let Some(prelude) = self.prelude {
1860 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1861 ModuleOrUniformRoot::Module(prelude),
1868 return Some(LexicalScopeBinding::Item(binding));
1874 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1876 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1877 .to_name_binding(self.arenas);
1878 return Some(LexicalScopeBinding::Item(binding));
1885 fn hygienic_lexical_parent(
1889 ) -> Option<Module<'a>> {
1890 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1891 return Some(self.macro_def_scope(span.remove_mark()));
1894 if let ModuleKind::Block(..) = module.kind {
1895 return Some(module.parent.unwrap().nearest_item_scope());
1901 fn hygienic_lexical_parent_with_compatibility_fallback(
1906 poisoned: &mut Option<NodeId>,
1907 ) -> Option<Module<'a>> {
1908 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1912 // We need to support the next case under a deprecation warning
1915 // ---- begin: this comes from a proc macro derive
1916 // mod implementation_details {
1917 // // Note that `MyStruct` is not in scope here.
1918 // impl SomeTrait for MyStruct { ... }
1922 // So we have to fall back to the module's parent during lexical resolution in this case.
1923 if let Some(parent) = module.parent {
1924 // Inner module is inside the macro, parent module is outside of the macro.
1925 if module.expansion != parent.expansion
1926 && module.expansion.is_descendant_of(parent.expansion)
1928 // The macro is a proc macro derive
1929 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
1930 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1931 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1932 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1933 *poisoned = Some(node_id);
1934 return module.parent;
1945 fn resolve_ident_in_module(
1947 module: ModuleOrUniformRoot<'a>,
1950 parent_scope: &ParentScope<'a>,
1953 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1954 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1955 .map_err(|(determinacy, _)| determinacy)
1958 fn resolve_ident_in_module_ext(
1960 module: ModuleOrUniformRoot<'a>,
1963 parent_scope: &ParentScope<'a>,
1966 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1967 let tmp_parent_scope;
1968 let mut adjusted_parent_scope = parent_scope;
1970 ModuleOrUniformRoot::Module(m) => {
1971 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
1973 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1974 adjusted_parent_scope = &tmp_parent_scope;
1977 ModuleOrUniformRoot::ExternPrelude => {
1978 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
1980 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1984 self.resolve_ident_in_module_unadjusted_ext(
1988 adjusted_parent_scope,
1995 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1996 debug!("resolve_crate_root({:?})", ident);
1997 let mut ctxt = ident.span.ctxt();
1998 let mark = if ident.name == kw::DollarCrate {
1999 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2000 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2001 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2002 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2003 // definitions actually produced by `macro` and `macro` definitions produced by
2004 // `macro_rules!`, but at least such configurations are not stable yet.
2005 ctxt = ctxt.normalize_to_macro_rules();
2007 "resolve_crate_root: marks={:?}",
2008 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2010 let mut iter = ctxt.marks().into_iter().rev().peekable();
2011 let mut result = None;
2012 // Find the last opaque mark from the end if it exists.
2013 while let Some(&(mark, transparency)) = iter.peek() {
2014 if transparency == Transparency::Opaque {
2015 result = Some(mark);
2022 "resolve_crate_root: found opaque mark {:?} {:?}",
2024 result.map(|r| r.expn_data())
2026 // Then find the last semi-transparent mark from the end if it exists.
2027 for (mark, transparency) in iter {
2028 if transparency == Transparency::SemiTransparent {
2029 result = Some(mark);
2035 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2037 result.map(|r| r.expn_data())
2041 debug!("resolve_crate_root: not DollarCrate");
2042 ctxt = ctxt.normalize_to_macros_2_0();
2043 ctxt.adjust(ExpnId::root())
2045 let module = match mark {
2046 Some(def) => self.macro_def_scope(def),
2049 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2052 return self.graph_root;
2055 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id });
2057 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2066 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2067 let mut module = self.get_module(module.normal_ancestor_id);
2068 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2069 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2070 module = self.get_module(parent.normal_ancestor_id);
2078 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2079 parent_scope: &ParentScope<'a>,
2082 crate_lint: CrateLint,
2083 ) -> PathResult<'a> {
2084 self.resolve_path_with_ribs(
2095 fn resolve_path_with_ribs(
2098 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2099 parent_scope: &ParentScope<'a>,
2102 crate_lint: CrateLint,
2103 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2104 ) -> PathResult<'a> {
2105 let mut module = None;
2106 let mut allow_super = true;
2107 let mut second_binding = None;
2110 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2111 path_span={:?}, crate_lint={:?})",
2112 path, opt_ns, record_used, path_span, crate_lint,
2115 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2116 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2117 let record_segment_res = |this: &mut Self, res| {
2119 if let Some(id) = id {
2120 if !this.partial_res_map.contains_key(&id) {
2121 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2122 this.record_partial_res(id, PartialRes::new(res));
2128 let is_last = i == path.len() - 1;
2129 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2130 let name = ident.name;
2132 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2135 if allow_super && name == kw::Super {
2136 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2137 let self_module = match i {
2138 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2140 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2144 if let Some(self_module) = self_module {
2145 if let Some(parent) = self_module.parent {
2146 module = Some(ModuleOrUniformRoot::Module(
2147 self.resolve_self(&mut ctxt, parent),
2152 let msg = "there are too many leading `super` keywords".to_string();
2153 return PathResult::Failed {
2157 is_error_from_last_segment: false,
2161 if name == kw::SelfLower {
2162 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2163 module = Some(ModuleOrUniformRoot::Module(
2164 self.resolve_self(&mut ctxt, parent_scope.module),
2168 if name == kw::PathRoot && ident.span.rust_2018() {
2169 module = Some(ModuleOrUniformRoot::ExternPrelude);
2172 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2173 // `::a::b` from 2015 macro on 2018 global edition
2174 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2177 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2178 // `::a::b`, `crate::a::b` or `$crate::a::b`
2179 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2185 // Report special messages for path segment keywords in wrong positions.
2186 if ident.is_path_segment_keyword() && i != 0 {
2187 let name_str = if name == kw::PathRoot {
2188 "crate root".to_string()
2190 format!("`{}`", name)
2192 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2193 format!("global paths cannot start with {}", name_str)
2195 format!("{} in paths can only be used in start position", name_str)
2197 return PathResult::Failed {
2201 is_error_from_last_segment: false,
2205 enum FindBindingResult<'a> {
2206 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2207 PathResult(PathResult<'a>),
2209 let find_binding_in_ns = |this: &mut Self, ns| {
2210 let binding = if let Some(module) = module {
2211 this.resolve_ident_in_module(
2219 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2220 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2221 this.early_resolve_ident_in_lexical_scope(
2230 let record_used_id = if record_used {
2231 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2235 match this.resolve_ident_in_lexical_scope(
2243 // we found a locally-imported or available item/module
2244 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2245 // we found a local variable or type param
2246 Some(LexicalScopeBinding::Res(res))
2247 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2249 record_segment_res(this, res);
2250 return FindBindingResult::PathResult(PathResult::NonModule(
2251 PartialRes::with_unresolved_segments(res, path.len() - 1),
2254 _ => Err(Determinacy::determined(record_used)),
2257 FindBindingResult::Binding(binding)
2259 let binding = match find_binding_in_ns(self, ns) {
2260 FindBindingResult::PathResult(x) => return x,
2261 FindBindingResult::Binding(binding) => binding,
2266 second_binding = Some(binding);
2268 let res = binding.res();
2269 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2270 if let Some(next_module) = binding.module() {
2271 module = Some(ModuleOrUniformRoot::Module(next_module));
2272 record_segment_res(self, res);
2273 } else if res == Res::ToolMod && i + 1 != path.len() {
2274 if binding.is_import() {
2278 "cannot use a tool module through an import",
2280 .span_note(binding.span, "the tool module imported here")
2283 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2284 return PathResult::NonModule(PartialRes::new(res));
2285 } else if res == Res::Err {
2286 return PathResult::NonModule(PartialRes::new(Res::Err));
2287 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2288 self.lint_if_path_starts_with_module(
2294 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2299 let label = format!(
2300 "`{}` is {} {}, not a module",
2306 return PathResult::Failed {
2310 is_error_from_last_segment: is_last,
2314 Err(Undetermined) => return PathResult::Indeterminate,
2315 Err(Determined) => {
2316 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2317 if opt_ns.is_some() && !module.is_normal() {
2318 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2319 module.res().unwrap(),
2324 let module_res = match module {
2325 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2328 let (label, suggestion) = if module_res == self.graph_root.res() {
2329 let is_mod = |res| match res {
2330 Res::Def(DefKind::Mod, _) => true,
2333 let mut candidates =
2334 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
2335 candidates.sort_by_cached_key(|c| {
2336 (c.path.segments.len(), pprust::path_to_string(&c.path))
2338 if let Some(candidate) = candidates.get(0) {
2340 String::from("unresolved import"),
2342 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2343 String::from("a similar path exists"),
2344 Applicability::MaybeIncorrect,
2348 (format!("maybe a missing crate `{}`?", ident), None)
2351 (format!("use of undeclared type or module `{}`", ident), None)
2354 format!("could not find `{}` in `{}`", ident, path[i - 1].ident);
2355 if ns == TypeNS || ns == ValueNS {
2356 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2357 if let FindBindingResult::Binding(Ok(binding)) =
2358 find_binding_in_ns(self, ns_to_try)
2360 let mut found = |what| {
2362 "expected {}, found {} `{}` in `{}`",
2369 if binding.module().is_some() {
2372 match binding.res() {
2373 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2374 _ => found(ns_to_try.descr()),
2381 return PathResult::Failed {
2385 is_error_from_last_segment: is_last,
2391 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2393 PathResult::Module(match module {
2394 Some(module) => module,
2395 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2396 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2400 fn lint_if_path_starts_with_module(
2402 crate_lint: CrateLint,
2405 second_binding: Option<&NameBinding<'_>>,
2407 let (diag_id, diag_span) = match crate_lint {
2408 CrateLint::No => return,
2409 CrateLint::SimplePath(id) => (id, path_span),
2410 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2411 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2414 let first_name = match path.get(0) {
2415 // In the 2018 edition this lint is a hard error, so nothing to do
2416 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2420 // We're only interested in `use` paths which should start with
2421 // `{{root}}` currently.
2422 if first_name != kw::PathRoot {
2427 // If this import looks like `crate::...` it's already good
2428 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2429 // Otherwise go below to see if it's an extern crate
2431 // If the path has length one (and it's `PathRoot` most likely)
2432 // then we don't know whether we're gonna be importing a crate or an
2433 // item in our crate. Defer this lint to elsewhere
2437 // If the first element of our path was actually resolved to an
2438 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2439 // warning, this looks all good!
2440 if let Some(binding) = second_binding {
2441 if let NameBindingKind::Import { import, .. } = binding.kind {
2442 // Careful: we still want to rewrite paths from renamed extern crates.
2443 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2449 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2450 self.lint_buffer.buffer_lint_with_diagnostic(
2451 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2454 "absolute paths must start with `self`, `super`, \
2455 `crate`, or an external crate name in the 2018 edition",
2460 // Validate a local resolution (from ribs).
2461 fn validate_res_from_ribs(
2468 all_ribs: &[Rib<'a>],
2470 debug!("validate_res_from_ribs({:?})", res);
2471 let ribs = &all_ribs[rib_index + 1..];
2473 // An invalid forward use of a type parameter from a previous default.
2474 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2476 let res_error = if rib_ident.name == kw::SelfUpper {
2477 ResolutionError::SelfInTyParamDefault
2479 ResolutionError::ForwardDeclaredTyParam
2481 self.report_error(span, res_error);
2483 assert_eq!(res, Res::Err);
2489 use ResolutionError::*;
2490 let mut res_err = None;
2495 | ClosureOrAsyncRibKind
2497 | MacroDefinition(..)
2498 | ForwardTyParamBanRibKind => {
2499 // Nothing to do. Continue.
2501 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2502 // This was an attempt to access an upvar inside a
2503 // named function item. This is not allowed, so we
2506 // We don't immediately trigger a resolve error, because
2507 // we want certain other resolution errors (namely those
2508 // emitted for `ConstantItemRibKind` below) to take
2510 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2513 ConstantItemRibKind(_) => {
2514 // Still doesn't deal with upvars
2516 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2520 ConstParamTyRibKind => {
2522 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2528 if let Some(res_err) = res_err {
2529 self.report_error(span, res_err);
2533 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2534 let mut in_ty_param_default = false;
2536 let has_generic_params = match rib.kind {
2538 | ClosureOrAsyncRibKind
2541 | MacroDefinition(..) => {
2542 // Nothing to do. Continue.
2546 // We only forbid constant items if we are inside of type defaults,
2547 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2548 ForwardTyParamBanRibKind => {
2549 in_ty_param_default = true;
2552 ConstantItemRibKind(trivial) => {
2553 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2554 if !trivial && self.session.features_untracked().min_const_generics {
2558 ResolutionError::ParamInNonTrivialAnonConst(rib_ident.name),
2564 if in_ty_param_default {
2568 ResolutionError::ParamInAnonConstInTyDefault(
2579 // This was an attempt to use a type parameter outside its scope.
2580 ItemRibKind(has_generic_params) => has_generic_params,
2581 FnItemRibKind => HasGenericParams::Yes,
2582 ConstParamTyRibKind => {
2586 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2596 ResolutionError::GenericParamsFromOuterFunction(
2605 Res::Def(DefKind::ConstParam, _) => {
2606 let mut ribs = ribs.iter().peekable();
2607 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2608 // When declaring const parameters inside function signatures, the first rib
2609 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2610 // (spuriously) conflicting with the const param.
2614 let mut in_ty_param_default = false;
2616 let has_generic_params = match rib.kind {
2618 | ClosureOrAsyncRibKind
2621 | MacroDefinition(..) => continue,
2623 // We only forbid constant items if we are inside of type defaults,
2624 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2625 ForwardTyParamBanRibKind => {
2626 in_ty_param_default = true;
2629 ConstantItemRibKind(trivial) => {
2630 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2631 if !trivial && self.session.features_untracked().min_const_generics {
2635 ResolutionError::ParamInNonTrivialAnonConst(rib_ident.name),
2641 if in_ty_param_default {
2645 ResolutionError::ParamInAnonConstInTyDefault(
2656 ItemRibKind(has_generic_params) => has_generic_params,
2657 FnItemRibKind => HasGenericParams::Yes,
2658 ConstParamTyRibKind => {
2662 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2669 // This was an attempt to use a const parameter outside its scope.
2673 ResolutionError::GenericParamsFromOuterFunction(
2687 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2688 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2689 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2690 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2694 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2695 vis.is_accessible_from(module.normal_ancestor_id, self)
2698 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2699 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2700 if !ptr::eq(module, old_module) {
2701 span_bug!(binding.span, "parent module is reset for binding");
2706 fn disambiguate_macro_rules_vs_modularized(
2708 macro_rules: &'a NameBinding<'a>,
2709 modularized: &'a NameBinding<'a>,
2711 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2712 // is disambiguated to mitigate regressions from macro modularization.
2713 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2715 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2716 self.binding_parent_modules.get(&PtrKey(modularized)),
2718 (Some(macro_rules), Some(modularized)) => {
2719 macro_rules.normal_ancestor_id == modularized.normal_ancestor_id
2720 && modularized.is_ancestor_of(macro_rules)
2726 fn report_errors(&mut self, krate: &Crate) {
2727 self.report_with_use_injections(krate);
2729 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2730 let msg = "macro-expanded `macro_export` macros from the current crate \
2731 cannot be referred to by absolute paths";
2732 self.lint_buffer.buffer_lint_with_diagnostic(
2733 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2737 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2741 for ambiguity_error in &self.ambiguity_errors {
2742 self.report_ambiguity_error(ambiguity_error);
2745 let mut reported_spans = FxHashSet::default();
2746 for error in &self.privacy_errors {
2747 if reported_spans.insert(error.dedup_span) {
2748 self.report_privacy_error(error);
2753 fn report_with_use_injections(&mut self, krate: &Crate) {
2754 for UseError { mut err, candidates, def_id, instead, suggestion } in
2755 self.use_injections.drain(..)
2757 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2758 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2762 if !candidates.is_empty() {
2763 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2764 } else if let Some((span, msg, sugg, appl)) = suggestion {
2765 err.span_suggestion(span, msg, sugg, appl);
2771 fn report_conflict<'b>(
2776 new_binding: &NameBinding<'b>,
2777 old_binding: &NameBinding<'b>,
2779 // Error on the second of two conflicting names
2780 if old_binding.span.lo() > new_binding.span.lo() {
2781 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2784 let container = match parent.kind {
2785 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2786 ModuleKind::Block(..) => "block",
2789 let old_noun = match old_binding.is_import() {
2791 false => "definition",
2794 let new_participle = match new_binding.is_import() {
2800 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2802 if let Some(s) = self.name_already_seen.get(&name) {
2808 let old_kind = match (ns, old_binding.module()) {
2809 (ValueNS, _) => "value",
2810 (MacroNS, _) => "macro",
2811 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2812 (TypeNS, Some(module)) if module.is_normal() => "module",
2813 (TypeNS, Some(module)) if module.is_trait() => "trait",
2814 (TypeNS, _) => "type",
2817 let msg = format!("the name `{}` is defined multiple times", name);
2819 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2820 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2821 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2822 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2823 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2825 _ => match (old_binding.is_import(), new_binding.is_import()) {
2826 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2827 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2828 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2833 "`{}` must be defined only once in the {} namespace of this {}",
2839 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2841 self.session.source_map().guess_head_span(old_binding.span),
2842 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2845 // See https://github.com/rust-lang/rust/issues/32354
2846 use NameBindingKind::Import;
2847 let import = match (&new_binding.kind, &old_binding.kind) {
2848 // If there are two imports where one or both have attributes then prefer removing the
2849 // import without attributes.
2850 (Import { import: new, .. }, Import { import: old, .. })
2852 !new_binding.span.is_dummy()
2853 && !old_binding.span.is_dummy()
2854 && (new.has_attributes || old.has_attributes)
2857 if old.has_attributes {
2858 Some((new, new_binding.span, true))
2860 Some((old, old_binding.span, true))
2863 // Otherwise prioritize the new binding.
2864 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
2865 Some((import, new_binding.span, other.is_import()))
2867 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
2868 Some((import, old_binding.span, other.is_import()))
2873 // Check if the target of the use for both bindings is the same.
2874 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2875 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2877 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2878 // Only suggest removing an import if both bindings are to the same def, if both spans
2879 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2880 // been introduced by a item.
2881 let should_remove_import = duplicate
2883 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2886 Some((import, span, true)) if should_remove_import && import.is_nested() => {
2887 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
2889 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
2890 // Simple case - remove the entire import. Due to the above match arm, this can
2891 // only be a single use so just remove it entirely.
2892 err.tool_only_span_suggestion(
2893 import.use_span_with_attributes,
2894 "remove unnecessary import",
2896 Applicability::MaybeIncorrect,
2899 Some((import, span, _)) => {
2900 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
2906 self.name_already_seen.insert(name, span);
2909 /// This function adds a suggestion to change the binding name of a new import that conflicts
2910 /// with an existing import.
2912 /// ```text,ignore (diagnostic)
2913 /// help: you can use `as` to change the binding name of the import
2915 /// LL | use foo::bar as other_bar;
2916 /// | ^^^^^^^^^^^^^^^^^^^^^
2918 fn add_suggestion_for_rename_of_use(
2920 err: &mut DiagnosticBuilder<'_>,
2922 import: &Import<'_>,
2925 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2926 format!("Other{}", name)
2928 format!("other_{}", name)
2931 let mut suggestion = None;
2933 ImportKind::Single { type_ns_only: true, .. } => {
2934 suggestion = Some(format!("self as {}", suggested_name))
2936 ImportKind::Single { source, .. } => {
2938 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2940 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2941 if pos <= snippet.len() {
2942 suggestion = Some(format!(
2946 if snippet.ends_with(';') { ";" } else { "" }
2952 ImportKind::ExternCrate { source, target, .. } => {
2953 suggestion = Some(format!(
2954 "extern crate {} as {};",
2955 source.unwrap_or(target.name),
2959 _ => unreachable!(),
2962 let rename_msg = "you can use `as` to change the binding name of the import";
2963 if let Some(suggestion) = suggestion {
2964 err.span_suggestion(
2968 Applicability::MaybeIncorrect,
2971 err.span_label(binding_span, rename_msg);
2975 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2976 /// nested. In the following example, this function will be invoked to remove the `a` binding
2977 /// in the second use statement:
2979 /// ```ignore (diagnostic)
2980 /// use issue_52891::a;
2981 /// use issue_52891::{d, a, e};
2984 /// The following suggestion will be added:
2986 /// ```ignore (diagnostic)
2987 /// use issue_52891::{d, a, e};
2988 /// ^-- help: remove unnecessary import
2991 /// If the nested use contains only one import then the suggestion will remove the entire
2994 /// It is expected that the provided import is nested - this isn't checked by the
2995 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2996 /// as characters expected by span manipulations won't be present.
2997 fn add_suggestion_for_duplicate_nested_use(
2999 err: &mut DiagnosticBuilder<'_>,
3000 import: &Import<'_>,
3003 assert!(import.is_nested());
3004 let message = "remove unnecessary import";
3006 // Two examples will be used to illustrate the span manipulations we're doing:
3008 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3009 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3010 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3011 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3013 let (found_closing_brace, span) =
3014 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3016 // If there was a closing brace then identify the span to remove any trailing commas from
3017 // previous imports.
3018 if found_closing_brace {
3019 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3020 err.tool_only_span_suggestion(
3024 Applicability::MaybeIncorrect,
3027 // Remove the entire line if we cannot extend the span back, this indicates a
3028 // `issue_52891::{self}` case.
3029 err.span_suggestion(
3030 import.use_span_with_attributes,
3033 Applicability::MaybeIncorrect,
3040 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3043 fn extern_prelude_get(
3047 ) -> Option<&'a NameBinding<'a>> {
3048 if ident.is_path_segment_keyword() {
3049 // Make sure `self`, `super` etc produce an error when passed to here.
3052 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3053 if let Some(binding) = entry.extern_crate_item {
3054 if !speculative && entry.introduced_by_item {
3055 self.record_use(ident, TypeNS, binding, false);
3059 let crate_id = if !speculative {
3060 self.crate_loader.process_path_extern(ident.name, ident.span)
3062 self.crate_loader.maybe_process_path_extern(ident.name)?
3064 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3066 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3067 .to_name_binding(self.arenas),
3073 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3074 /// isn't something that can be returned because it can't be made to live that long,
3075 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3076 /// just that an error occurred.
3077 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3078 pub fn resolve_str_path_error(
3084 ) -> Result<(ast::Path, Res), ()> {
3085 let path = if path_str.starts_with("::") {
3088 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3089 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3090 .map(|i| self.new_ast_path_segment(i))
3098 .map(Ident::from_str)
3099 .map(|i| self.new_ast_path_segment(i))
3103 let module = self.get_module(module_id);
3104 let parent_scope = &ParentScope::module(module);
3105 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3109 // Resolve a path passed from rustdoc or HIR lowering.
3110 fn resolve_ast_path(
3114 parent_scope: &ParentScope<'a>,
3115 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3116 match self.resolve_path(
3117 &Segment::from_path(path),
3124 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3125 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3126 Ok(path_res.base_res())
3128 PathResult::NonModule(..) => Err((
3130 ResolutionError::FailedToResolve {
3131 label: String::from("type-relative paths are not supported in this context"),
3135 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3136 PathResult::Failed { span, label, suggestion, .. } => {
3137 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3142 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3143 let mut seg = ast::PathSegment::from_ident(ident);
3144 seg.id = self.next_node_id();
3149 pub fn graph_root(&self) -> Module<'a> {
3154 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3158 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3160 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3161 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3165 fn names_to_string(names: &[Symbol]) -> String {
3166 let mut result = String::new();
3167 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3169 result.push_str("::");
3171 if Ident::with_dummy_span(*name).is_raw_guess() {
3172 result.push_str("r#");
3174 result.push_str(&name.as_str());
3179 fn path_names_to_string(path: &Path) -> String {
3180 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3183 /// A somewhat inefficient routine to obtain the name of a module.
3184 fn module_to_string(module: Module<'_>) -> Option<String> {
3185 let mut names = Vec::new();
3187 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3188 if let ModuleKind::Def(.., name) = module.kind {
3189 if let Some(parent) = module.parent {
3191 collect_mod(names, parent);
3194 names.push(Symbol::intern("<opaque>"));
3195 collect_mod(names, module.parent.unwrap());
3198 collect_mod(&mut names, module);
3200 if names.is_empty() {
3204 Some(names_to_string(&names))
3207 #[derive(Copy, Clone, Debug)]
3209 /// Do not issue the lint.
3212 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3213 /// In this case, we can take the span of that path.
3216 /// This lint comes from a `use` statement. In this case, what we
3217 /// care about really is the *root* `use` statement; e.g., if we
3218 /// have nested things like `use a::{b, c}`, we care about the
3220 UsePath { root_id: NodeId, root_span: Span },
3222 /// This is the "trait item" from a fully qualified path. For example,
3223 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3224 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3225 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3229 fn node_id(&self) -> Option<NodeId> {
3231 CrateLint::No => None,
3232 CrateLint::SimplePath(id)
3233 | CrateLint::UsePath { root_id: id, .. }
3234 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3239 pub fn provide(providers: &mut Providers) {
3240 late::lifetimes::provide(providers);