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};
27 use rustc_ast::node_id::NodeMap;
28 use rustc_ast::unwrap_or;
29 use rustc_ast::visit::{self, Visitor};
30 use rustc_ast_lowering::ResolverAstLowering;
31 use rustc_ast_pretty::pprust;
32 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
33 use rustc_data_structures::ptr_key::PtrKey;
34 use rustc_data_structures::sync::Lrc;
35 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
36 use rustc_expand::base::SyntaxExtension;
37 use rustc_hir::def::Namespace::*;
38 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
39 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
40 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
41 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
42 use rustc_hir::TraitCandidate;
43 use rustc_index::vec::IndexVec;
44 use rustc_metadata::creader::{CStore, CrateLoader};
45 use rustc_middle::hir::exports::ExportMap;
46 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
47 use rustc_middle::span_bug;
48 use rustc_middle::ty::query::Providers;
49 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
50 use rustc_session::lint;
51 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
52 use rustc_session::Session;
53 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
54 use rustc_span::source_map::Spanned;
55 use rustc_span::symbol::{kw, sym, Ident, Symbol};
56 use rustc_span::{Span, DUMMY_SP};
59 use std::cell::{Cell, RefCell};
60 use std::collections::BTreeSet;
61 use std::{cmp, fmt, iter, ptr};
63 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
64 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
65 use imports::{Import, ImportKind, ImportResolver, NameResolution};
66 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
67 use macros::{MacroRulesBinding, MacroRulesScope};
69 type Res = def::Res<NodeId>;
71 mod build_reduced_graph;
84 #[derive(Copy, Clone, PartialEq, Debug)]
85 pub enum Determinacy {
91 fn determined(determined: bool) -> Determinacy {
92 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
96 /// A specific scope in which a name can be looked up.
97 /// This enum is currently used only for early resolution (imports and macros),
98 /// but not for late resolution yet.
99 #[derive(Clone, Copy)]
101 DeriveHelpers(ExpnId),
103 MacroRules(MacroRulesScope<'a>),
115 /// Names from different contexts may want to visit different subsets of all specific scopes
116 /// with different restrictions when looking up the resolution.
117 /// This enum is currently used only for early resolution (imports and macros),
118 /// but not for late resolution yet.
120 /// All scopes with the given namespace.
121 All(Namespace, /*is_import*/ bool),
122 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
123 AbsolutePath(Namespace),
124 /// All scopes with macro namespace and the given macro kind restriction.
128 /// Everything you need to know about a name's location to resolve it.
129 /// Serves as a starting point for the scope visitor.
130 /// This struct is currently used only for early resolution (imports and macros),
131 /// but not for late resolution yet.
132 #[derive(Clone, Copy, Debug)]
133 pub struct ParentScope<'a> {
136 macro_rules: MacroRulesScope<'a>,
137 derives: &'a [ast::Path],
140 impl<'a> ParentScope<'a> {
141 /// Creates a parent scope with the passed argument used as the module scope component,
142 /// and other scope components set to default empty values.
143 pub fn module(module: Module<'a>) -> ParentScope<'a> {
146 expansion: ExpnId::root(),
147 macro_rules: MacroRulesScope::Empty,
154 struct BindingError {
156 origin: BTreeSet<Span>,
157 target: BTreeSet<Span>,
161 impl PartialOrd for BindingError {
162 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
163 Some(self.cmp(other))
167 impl PartialEq for BindingError {
168 fn eq(&self, other: &BindingError) -> bool {
169 self.name == other.name
173 impl Ord for BindingError {
174 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
175 self.name.cmp(&other.name)
179 enum ResolutionError<'a> {
180 /// Error E0401: can't use type or const parameters from outer function.
181 GenericParamsFromOuterFunction(Res, HasGenericParams),
182 /// Error E0403: the name is already used for a type or const parameter in this generic
184 NameAlreadyUsedInParameterList(Symbol, Span),
185 /// Error E0407: method is not a member of trait.
186 MethodNotMemberOfTrait(Symbol, &'a str),
187 /// Error E0437: type is not a member of trait.
188 TypeNotMemberOfTrait(Symbol, &'a str),
189 /// Error E0438: const is not a member of trait.
190 ConstNotMemberOfTrait(Symbol, &'a str),
191 /// Error E0408: variable `{}` is not bound in all patterns.
192 VariableNotBoundInPattern(&'a BindingError),
193 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
194 VariableBoundWithDifferentMode(Symbol, Span),
195 /// Error E0415: identifier is bound more than once in this parameter list.
196 IdentifierBoundMoreThanOnceInParameterList(Symbol),
197 /// Error E0416: identifier is bound more than once in the same pattern.
198 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
199 /// Error E0426: use of undeclared label.
200 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
201 /// Error E0429: `self` imports are only allowed within a `{ }` list.
202 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
203 /// Error E0430: `self` import can only appear once in the list.
204 SelfImportCanOnlyAppearOnceInTheList,
205 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
206 SelfImportOnlyInImportListWithNonEmptyPrefix,
207 /// Error E0433: failed to resolve.
208 FailedToResolve { label: String, suggestion: Option<Suggestion> },
209 /// Error E0434: can't capture dynamic environment in a fn item.
210 CannotCaptureDynamicEnvironmentInFnItem,
211 /// Error E0435: attempt to use a non-constant value in a constant.
212 AttemptToUseNonConstantValueInConstant,
213 /// Error E0530: `X` bindings cannot shadow `Y`s.
214 BindingShadowsSomethingUnacceptable(&'static str, Symbol, &'a NameBinding<'a>),
215 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
216 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
217 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
218 ParamInTyOfConstParam(Symbol),
219 /// constant values inside of type parameter defaults must not depend on generic parameters.
220 ParamInAnonConstInTyDefault(Symbol),
221 /// Error E0735: type parameters with a default cannot use `Self`
222 SelfInTyParamDefault,
223 /// Error E0767: use of unreachable label
224 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
227 enum VisResolutionError<'a> {
228 Relative2018(Span, &'a ast::Path),
230 FailedToResolve(Span, String, Option<Suggestion>),
231 ExpectedFound(Span, String, Res),
236 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
237 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
238 #[derive(Clone, Copy, Debug)]
242 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
243 /// nonsensical suggestions.
244 has_generic_args: bool,
248 fn from_path(path: &Path) -> Vec<Segment> {
249 path.segments.iter().map(|s| s.into()).collect()
252 fn from_ident(ident: Ident) -> Segment {
253 Segment { ident, id: None, has_generic_args: false }
256 fn names_to_string(segments: &[Segment]) -> String {
257 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
261 impl<'a> From<&'a ast::PathSegment> for Segment {
262 fn from(seg: &'a ast::PathSegment) -> Segment {
263 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
267 struct UsePlacementFinder {
268 target_module: NodeId,
273 impl UsePlacementFinder {
274 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
275 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
276 visit::walk_crate(&mut finder, krate);
277 (finder.span, finder.found_use)
281 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
284 module: &'tcx ast::Mod,
286 _: &[ast::Attribute],
289 if self.span.is_some() {
292 if node_id != self.target_module {
293 visit::walk_mod(self, module);
296 // find a use statement
297 for item in &module.items {
299 ItemKind::Use(..) => {
300 // don't suggest placing a use before the prelude
301 // import or other generated ones
302 if !item.span.from_expansion() {
303 self.span = Some(item.span.shrink_to_lo());
304 self.found_use = true;
308 // don't place use before extern crate
309 ItemKind::ExternCrate(_) => {}
310 // but place them before the first other item
312 if self.span.map_or(true, |span| item.span < span) {
313 if !item.span.from_expansion() {
314 // don't insert between attributes and an item
315 if item.attrs.is_empty() {
316 self.span = Some(item.span.shrink_to_lo());
318 // find the first attribute on the item
319 for attr in &item.attrs {
320 if self.span.map_or(true, |span| attr.span < span) {
321 self.span = Some(attr.span.shrink_to_lo());
333 /// An intermediate resolution result.
335 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
336 /// items are visible in their whole block, while `Res`es only from the place they are defined
339 enum LexicalScopeBinding<'a> {
340 Item(&'a NameBinding<'a>),
344 impl<'a> LexicalScopeBinding<'a> {
345 fn res(self) -> Res {
347 LexicalScopeBinding::Item(binding) => binding.res(),
348 LexicalScopeBinding::Res(res) => res,
353 #[derive(Copy, Clone, Debug)]
354 enum ModuleOrUniformRoot<'a> {
358 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
359 CrateRootAndExternPrelude,
361 /// Virtual module that denotes resolution in extern prelude.
362 /// Used for paths starting with `::` on 2018 edition.
365 /// Virtual module that denotes resolution in current scope.
366 /// Used only for resolving single-segment imports. The reason it exists is that import paths
367 /// are always split into two parts, the first of which should be some kind of module.
371 impl ModuleOrUniformRoot<'_> {
372 fn same_def(lhs: Self, rhs: Self) -> bool {
374 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
375 lhs.def_id() == rhs.def_id()
378 ModuleOrUniformRoot::CrateRootAndExternPrelude,
379 ModuleOrUniformRoot::CrateRootAndExternPrelude,
381 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
382 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
388 #[derive(Clone, Debug)]
389 enum PathResult<'a> {
390 Module(ModuleOrUniformRoot<'a>),
391 NonModule(PartialRes),
396 suggestion: Option<Suggestion>,
397 is_error_from_last_segment: bool,
402 /// An anonymous module; e.g., just a block.
407 /// { // This is an anonymous module
408 /// f(); // This resolves to (2) as we are inside the block.
411 /// f(); // Resolves to (1)
415 /// Any module with a name.
419 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
420 /// * A trait or an enum (it implicitly contains associated types, methods and variant
422 Def(DefKind, DefId, Symbol),
426 /// Get name of the module.
427 pub fn name(&self) -> Option<Symbol> {
429 ModuleKind::Block(..) => None,
430 ModuleKind::Def(.., name) => Some(*name),
435 /// A key that identifies a binding in a given `Module`.
437 /// Multiple bindings in the same module can have the same key (in a valid
438 /// program) if all but one of them come from glob imports.
439 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
441 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
445 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
446 /// `_` in the expanded AST that introduced this binding.
450 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
452 /// One node in the tree of modules.
453 pub struct ModuleData<'a> {
454 parent: Option<Module<'a>>,
457 // The def id of the closest normal module (`mod`) ancestor (including this module).
458 normal_ancestor_id: DefId,
460 // Mapping between names and their (possibly in-progress) resolutions in this module.
461 // Resolutions in modules from other crates are not populated until accessed.
462 lazy_resolutions: Resolutions<'a>,
463 // True if this is a module from other crate that needs to be populated on access.
464 populate_on_access: Cell<bool>,
466 // Macro invocations that can expand into items in this module.
467 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
469 no_implicit_prelude: bool,
471 glob_importers: RefCell<Vec<&'a Import<'a>>>,
472 globs: RefCell<Vec<&'a Import<'a>>>,
474 // Used to memoize the traits in this module for faster searches through all traits in scope.
475 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
477 /// Span of the module itself. Used for error reporting.
483 type Module<'a> = &'a ModuleData<'a>;
485 impl<'a> ModuleData<'a> {
487 parent: Option<Module<'a>>,
489 normal_ancestor_id: DefId,
497 lazy_resolutions: Default::default(),
498 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
499 unexpanded_invocations: Default::default(),
500 no_implicit_prelude: false,
501 glob_importers: RefCell::new(Vec::new()),
502 globs: RefCell::new(Vec::new()),
503 traits: RefCell::new(None),
509 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
511 R: AsMut<Resolver<'a>>,
512 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
514 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
515 if let Some(binding) = name_resolution.borrow().binding {
516 f(resolver, key.ident, key.ns, binding);
521 fn res(&self) -> Option<Res> {
523 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
528 fn def_id(&self) -> Option<DefId> {
530 ModuleKind::Def(_, def_id, _) => Some(def_id),
535 // `self` resolves to the first module ancestor that `is_normal`.
536 fn is_normal(&self) -> bool {
538 ModuleKind::Def(DefKind::Mod, _, _) => true,
543 fn is_trait(&self) -> bool {
545 ModuleKind::Def(DefKind::Trait, _, _) => true,
550 fn nearest_item_scope(&'a self) -> Module<'a> {
552 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
553 self.parent.expect("enum or trait module without a parent")
559 fn is_ancestor_of(&self, mut other: &Self) -> bool {
560 while !ptr::eq(self, other) {
561 if let Some(parent) = other.parent {
571 impl<'a> fmt::Debug for ModuleData<'a> {
572 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
573 write!(f, "{:?}", self.res())
577 /// Records a possibly-private value, type, or module definition.
578 #[derive(Clone, Debug)]
579 pub struct NameBinding<'a> {
580 kind: NameBindingKind<'a>,
581 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
587 pub trait ToNameBinding<'a> {
588 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
591 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
592 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
597 #[derive(Clone, Debug)]
598 enum NameBindingKind<'a> {
599 Res(Res, /* is_macro_export */ bool),
601 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
604 impl<'a> NameBindingKind<'a> {
605 /// Is this a name binding of a import?
606 fn is_import(&self) -> bool {
608 NameBindingKind::Import { .. } => true,
614 struct PrivacyError<'a> {
616 binding: &'a NameBinding<'a>,
620 struct UseError<'a> {
621 err: DiagnosticBuilder<'a>,
622 /// Candidates which user could `use` to access the missing type.
623 candidates: Vec<ImportSuggestion>,
624 /// The `DefId` of the module to place the use-statements in.
626 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
628 /// Extra free-form suggestion.
629 suggestion: Option<(Span, &'static str, String, Applicability)>,
632 #[derive(Clone, Copy, PartialEq, Debug)]
637 MacroRulesVsModularized,
645 fn descr(self) -> &'static str {
647 AmbiguityKind::Import => "name vs any other name during import resolution",
648 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
649 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
650 AmbiguityKind::MacroRulesVsModularized => {
651 "`macro_rules` vs non-`macro_rules` from other module"
653 AmbiguityKind::GlobVsOuter => {
654 "glob import vs any other name from outer scope during import/macro resolution"
656 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
657 AmbiguityKind::GlobVsExpanded => {
658 "glob import vs macro-expanded name in the same \
659 module during import/macro resolution"
661 AmbiguityKind::MoreExpandedVsOuter => {
662 "macro-expanded name vs less macro-expanded name \
663 from outer scope during import/macro resolution"
669 /// Miscellaneous bits of metadata for better ambiguity error reporting.
670 #[derive(Clone, Copy, PartialEq)]
671 enum AmbiguityErrorMisc {
678 struct AmbiguityError<'a> {
681 b1: &'a NameBinding<'a>,
682 b2: &'a NameBinding<'a>,
683 misc1: AmbiguityErrorMisc,
684 misc2: AmbiguityErrorMisc,
687 impl<'a> NameBinding<'a> {
688 fn module(&self) -> Option<Module<'a>> {
690 NameBindingKind::Module(module) => Some(module),
691 NameBindingKind::Import { binding, .. } => binding.module(),
696 fn res(&self) -> Res {
698 NameBindingKind::Res(res, _) => res,
699 NameBindingKind::Module(module) => module.res().unwrap(),
700 NameBindingKind::Import { binding, .. } => binding.res(),
704 fn is_ambiguity(&self) -> bool {
705 self.ambiguity.is_some()
707 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
712 fn is_possibly_imported_variant(&self) -> bool {
714 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
715 _ => self.is_variant(),
719 // We sometimes need to treat variants as `pub` for backwards compatibility.
720 fn pseudo_vis(&self) -> ty::Visibility {
721 if self.is_variant() && self.res().def_id().is_local() {
722 ty::Visibility::Public
728 fn is_variant(&self) -> bool {
730 NameBindingKind::Res(
731 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
738 fn is_extern_crate(&self) -> bool {
740 NameBindingKind::Import {
741 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
744 NameBindingKind::Module(&ModuleData {
745 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
747 }) => def_id.index == CRATE_DEF_INDEX,
752 fn is_import(&self) -> bool {
754 NameBindingKind::Import { .. } => true,
759 fn is_glob_import(&self) -> bool {
761 NameBindingKind::Import { import, .. } => import.is_glob(),
766 fn is_importable(&self) -> bool {
768 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _) => false,
773 fn is_macro_def(&self) -> bool {
775 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
780 fn macro_kind(&self) -> Option<MacroKind> {
781 self.res().macro_kind()
784 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
785 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
786 // Then this function returns `true` if `self` may emerge from a macro *after* that
787 // in some later round and screw up our previously found resolution.
788 // See more detailed explanation in
789 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
790 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
791 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
792 // Expansions are partially ordered, so "may appear after" is an inversion of
793 // "certainly appears before or simultaneously" and includes unordered cases.
794 let self_parent_expansion = self.expansion;
795 let other_parent_expansion = binding.expansion;
796 let certainly_before_other_or_simultaneously =
797 other_parent_expansion.is_descendant_of(self_parent_expansion);
798 let certainly_before_invoc_or_simultaneously =
799 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
800 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
804 /// Interns the names of the primitive types.
806 /// All other types are defined somewhere and possibly imported, but the primitive ones need
807 /// special handling, since they have no place of origin.
808 struct PrimitiveTypeTable {
809 primitive_types: FxHashMap<Symbol, PrimTy>,
812 impl PrimitiveTypeTable {
813 fn new() -> PrimitiveTypeTable {
814 let mut table = FxHashMap::default();
816 table.insert(sym::bool, Bool);
817 table.insert(sym::char, Char);
818 table.insert(sym::f32, Float(FloatTy::F32));
819 table.insert(sym::f64, Float(FloatTy::F64));
820 table.insert(sym::isize, Int(IntTy::Isize));
821 table.insert(sym::i8, Int(IntTy::I8));
822 table.insert(sym::i16, Int(IntTy::I16));
823 table.insert(sym::i32, Int(IntTy::I32));
824 table.insert(sym::i64, Int(IntTy::I64));
825 table.insert(sym::i128, Int(IntTy::I128));
826 table.insert(sym::str, Str);
827 table.insert(sym::usize, Uint(UintTy::Usize));
828 table.insert(sym::u8, Uint(UintTy::U8));
829 table.insert(sym::u16, Uint(UintTy::U16));
830 table.insert(sym::u32, Uint(UintTy::U32));
831 table.insert(sym::u64, Uint(UintTy::U64));
832 table.insert(sym::u128, Uint(UintTy::U128));
833 Self { primitive_types: table }
837 #[derive(Debug, Default, Clone)]
838 pub struct ExternPreludeEntry<'a> {
839 extern_crate_item: Option<&'a NameBinding<'a>>,
840 pub introduced_by_item: bool,
843 /// The main resolver class.
845 /// This is the visitor that walks the whole crate.
846 pub struct Resolver<'a> {
847 session: &'a Session,
849 definitions: Definitions,
851 graph_root: Module<'a>,
853 prelude: Option<Module<'a>>,
854 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
856 /// N.B., this is used only for better diagnostics, not name resolution itself.
857 has_self: FxHashSet<DefId>,
859 /// Names of fields of an item `DefId` accessible with dot syntax.
860 /// Used for hints during error reporting.
861 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
863 /// All imports known to succeed or fail.
864 determined_imports: Vec<&'a Import<'a>>,
866 /// All non-determined imports.
867 indeterminate_imports: Vec<&'a Import<'a>>,
869 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
870 /// We are resolving a last import segment during import validation.
871 last_import_segment: bool,
872 /// This binding should be ignored during in-module resolution, so that we don't get
873 /// "self-confirming" import resolutions during import validation.
874 unusable_binding: Option<&'a NameBinding<'a>>,
876 /// The idents for the primitive types.
877 primitive_type_table: PrimitiveTypeTable,
879 /// Resolutions for nodes that have a single resolution.
880 partial_res_map: NodeMap<PartialRes>,
881 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
882 import_res_map: NodeMap<PerNS<Option<Res>>>,
883 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
884 label_res_map: NodeMap<NodeId>,
886 /// `CrateNum` resolutions of `extern crate` items.
887 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
888 export_map: ExportMap<LocalDefId>,
889 trait_map: NodeMap<Vec<TraitCandidate>>,
891 /// A map from nodes to anonymous modules.
892 /// Anonymous modules are pseudo-modules that are implicitly created around items
893 /// contained within blocks.
895 /// For example, if we have this:
903 /// There will be an anonymous module created around `g` with the ID of the
904 /// entry block for `f`.
905 block_map: NodeMap<Module<'a>>,
906 /// A fake module that contains no definition and no prelude. Used so that
907 /// some AST passes can generate identifiers that only resolve to local or
909 empty_module: Module<'a>,
910 module_map: FxHashMap<LocalDefId, Module<'a>>,
911 extern_module_map: FxHashMap<DefId, Module<'a>>,
912 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
913 underscore_disambiguator: u32,
915 /// Maps glob imports to the names of items actually imported.
916 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
918 used_imports: FxHashSet<(NodeId, Namespace)>,
919 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
920 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
922 /// Privacy errors are delayed until the end in order to deduplicate them.
923 privacy_errors: Vec<PrivacyError<'a>>,
924 /// Ambiguity errors are delayed for deduplication.
925 ambiguity_errors: Vec<AmbiguityError<'a>>,
926 /// `use` injections are delayed for better placement and deduplication.
927 use_injections: Vec<UseError<'a>>,
928 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
929 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
931 arenas: &'a ResolverArenas<'a>,
932 dummy_binding: &'a NameBinding<'a>,
934 crate_loader: CrateLoader<'a>,
935 macro_names: FxHashSet<Ident>,
936 builtin_macros: FxHashMap<Symbol, SyntaxExtension>,
937 registered_attrs: FxHashSet<Ident>,
938 registered_tools: FxHashSet<Ident>,
939 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
940 all_macros: FxHashMap<Symbol, Res>,
941 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
942 dummy_ext_bang: Lrc<SyntaxExtension>,
943 dummy_ext_derive: Lrc<SyntaxExtension>,
944 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
945 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
946 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
947 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
948 proc_macro_stubs: FxHashSet<LocalDefId>,
949 /// Traces collected during macro resolution and validated when it's complete.
950 single_segment_macro_resolutions:
951 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
952 multi_segment_macro_resolutions:
953 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
954 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
955 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
956 /// Derive macros cannot modify the item themselves and have to store the markers in the global
957 /// context, so they attach the markers to derive container IDs using this resolver table.
958 containers_deriving_copy: FxHashSet<ExpnId>,
959 /// Parent scopes in which the macros were invoked.
960 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
961 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
962 /// `macro_rules` scopes *produced* by expanding the macro invocations,
963 /// include all the `macro_rules` items and other invocations generated by them.
964 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScope<'a>>,
965 /// Helper attributes that are in scope for the given expansion.
966 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
968 /// Avoid duplicated errors for "name already defined".
969 name_already_seen: FxHashMap<Symbol, Span>,
971 potentially_unused_imports: Vec<&'a Import<'a>>,
973 /// Table for mapping struct IDs into struct constructor IDs,
974 /// it's not used during normal resolution, only for better error reporting.
975 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
977 /// Features enabled for this crate.
978 active_features: FxHashSet<Symbol>,
980 /// Stores enum visibilities to properly build a reduced graph
981 /// when visiting the correspondent variants.
982 variant_vis: DefIdMap<ty::Visibility>,
984 lint_buffer: LintBuffer,
986 next_node_id: NodeId,
988 def_id_to_span: IndexVec<LocalDefId, Span>,
990 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
991 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
993 /// Indices of unnamed struct or variant fields with unresolved attributes.
994 placeholder_field_indices: FxHashMap<NodeId, usize>,
995 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
996 /// we know what parent node that fragment should be attached to thanks to this table.
997 invocation_parents: FxHashMap<ExpnId, LocalDefId>,
999 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1002 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1004 pub struct ResolverArenas<'a> {
1005 modules: TypedArena<ModuleData<'a>>,
1006 local_modules: RefCell<Vec<Module<'a>>>,
1007 name_bindings: TypedArena<NameBinding<'a>>,
1008 imports: TypedArena<Import<'a>>,
1009 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1010 macro_rules_bindings: TypedArena<MacroRulesBinding<'a>>,
1011 ast_paths: TypedArena<ast::Path>,
1014 impl<'a> ResolverArenas<'a> {
1015 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1016 let module = self.modules.alloc(module);
1017 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1018 self.local_modules.borrow_mut().push(module);
1022 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1023 self.local_modules.borrow()
1025 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1026 self.name_bindings.alloc(name_binding)
1028 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1029 self.imports.alloc(import)
1031 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1032 self.name_resolutions.alloc(Default::default())
1034 fn alloc_macro_rules_binding(
1036 binding: MacroRulesBinding<'a>,
1037 ) -> &'a MacroRulesBinding<'a> {
1038 self.macro_rules_bindings.alloc(binding)
1040 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1041 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1045 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1046 fn as_mut(&mut self) -> &mut Resolver<'a> {
1051 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1052 fn parent(self, id: DefId) -> Option<DefId> {
1053 match id.as_local() {
1054 Some(id) => self.definitions.def_key(id).parent,
1055 None => self.cstore().def_key(id).parent,
1057 .map(|index| DefId { index, ..id })
1061 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1062 /// the resolver is no longer needed as all the relevant information is inline.
1063 impl ResolverAstLowering for Resolver<'_> {
1064 fn def_key(&mut self, id: DefId) -> DefKey {
1065 if let Some(id) = id.as_local() {
1066 self.definitions().def_key(id)
1068 self.cstore().def_key(id)
1072 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1073 self.cstore().item_generics_num_lifetimes(def_id, sess)
1076 fn resolve_str_path(
1079 crate_root: Option<Symbol>,
1080 components: &[Symbol],
1082 ) -> (ast::Path, Res) {
1083 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1084 let segments = iter::once(Ident::with_dummy_span(root))
1088 .chain(components.iter().cloned())
1089 .map(Ident::with_dummy_span),
1091 .map(|i| self.new_ast_path_segment(i))
1092 .collect::<Vec<_>>();
1094 let path = ast::Path { span, segments };
1096 let parent_scope = &ParentScope::module(self.graph_root);
1097 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1099 Err((span, error)) => {
1100 self.report_error(span, error);
1107 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1108 self.partial_res_map.get(&id).cloned()
1111 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1112 self.import_res_map.get(&id).cloned().unwrap_or_default()
1115 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1116 self.label_res_map.get(&id).cloned()
1119 fn definitions(&mut self) -> &mut Definitions {
1120 &mut self.definitions
1123 fn lint_buffer(&mut self) -> &mut LintBuffer {
1124 &mut self.lint_buffer
1127 fn next_node_id(&mut self) -> NodeId {
1131 fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
1135 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1136 self.node_id_to_def_id.get(&node).copied()
1139 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1140 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1143 /// Adds a definition with a parent definition.
1147 node_id: ast::NodeId,
1153 !self.node_id_to_def_id.contains_key(&node_id),
1154 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1157 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1160 // Find the next free disambiguator for this key.
1161 let next_disambiguator = &mut self.next_disambiguator;
1162 let next_disambiguator = |parent, data| {
1163 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1164 let disambiguator = *next_disamb;
1165 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1169 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1171 assert_eq!(self.def_id_to_span.push(span), def_id);
1173 // Some things for which we allocate `LocalDefId`s don't correspond to
1174 // anything in the AST, so they don't have a `NodeId`. For these cases
1175 // we don't need a mapping from `NodeId` to `LocalDefId`.
1176 if node_id != ast::DUMMY_NODE_ID {
1177 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1178 self.node_id_to_def_id.insert(node_id, def_id);
1180 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1186 impl<'a> Resolver<'a> {
1188 session: &'a Session,
1191 metadata_loader: &'a MetadataLoaderDyn,
1192 arenas: &'a ResolverArenas<'a>,
1194 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1195 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1196 let graph_root = arenas.alloc_module(ModuleData {
1197 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1198 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1200 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1201 let empty_module = arenas.alloc_module(ModuleData {
1202 no_implicit_prelude: true,
1211 let mut module_map = FxHashMap::default();
1212 module_map.insert(LocalDefId { local_def_index: CRATE_DEF_INDEX }, graph_root);
1214 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1215 let root = definitions.get_root_def();
1217 let mut def_id_to_span = IndexVec::default();
1218 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1219 let mut def_id_to_node_id = IndexVec::default();
1220 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1221 let mut node_id_to_def_id = FxHashMap::default();
1222 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1224 let mut invocation_parents = FxHashMap::default();
1225 invocation_parents.insert(ExpnId::root(), root);
1227 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1231 .filter(|(_, entry)| entry.add_prelude)
1232 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1235 if !attr::contains_name(&krate.attrs, sym::no_core) {
1236 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1237 if !attr::contains_name(&krate.attrs, sym::no_std) {
1238 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1239 if session.rust_2018() {
1240 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1245 let (registered_attrs, registered_tools) =
1246 macros::registered_attrs_and_tools(session, &krate.attrs);
1248 let mut invocation_parent_scopes = FxHashMap::default();
1249 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1251 let features = session.features_untracked();
1252 let non_macro_attr =
1253 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1260 // The outermost module has def ID 0; this is not reflected in the
1266 has_self: FxHashSet::default(),
1267 field_names: FxHashMap::default(),
1269 determined_imports: Vec::new(),
1270 indeterminate_imports: Vec::new(),
1272 last_import_segment: false,
1273 unusable_binding: None,
1275 primitive_type_table: PrimitiveTypeTable::new(),
1277 partial_res_map: Default::default(),
1278 import_res_map: Default::default(),
1279 label_res_map: Default::default(),
1280 extern_crate_map: Default::default(),
1281 export_map: FxHashMap::default(),
1282 trait_map: Default::default(),
1283 underscore_disambiguator: 0,
1286 block_map: Default::default(),
1287 extern_module_map: FxHashMap::default(),
1288 binding_parent_modules: FxHashMap::default(),
1289 ast_transform_scopes: FxHashMap::default(),
1291 glob_map: Default::default(),
1293 used_imports: FxHashSet::default(),
1294 maybe_unused_trait_imports: Default::default(),
1295 maybe_unused_extern_crates: Vec::new(),
1297 privacy_errors: Vec::new(),
1298 ambiguity_errors: Vec::new(),
1299 use_injections: Vec::new(),
1300 macro_expanded_macro_export_errors: BTreeSet::new(),
1303 dummy_binding: arenas.alloc_name_binding(NameBinding {
1304 kind: NameBindingKind::Res(Res::Err, false),
1306 expansion: ExpnId::root(),
1308 vis: ty::Visibility::Public,
1311 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1312 macro_names: FxHashSet::default(),
1313 builtin_macros: Default::default(),
1316 macro_use_prelude: FxHashMap::default(),
1317 all_macros: FxHashMap::default(),
1318 macro_map: FxHashMap::default(),
1319 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1320 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1321 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1322 invocation_parent_scopes,
1323 output_macro_rules_scopes: Default::default(),
1324 helper_attrs: Default::default(),
1325 local_macro_def_scopes: FxHashMap::default(),
1326 name_already_seen: FxHashMap::default(),
1327 potentially_unused_imports: Vec::new(),
1328 struct_constructors: Default::default(),
1329 unused_macros: Default::default(),
1330 proc_macro_stubs: Default::default(),
1331 single_segment_macro_resolutions: Default::default(),
1332 multi_segment_macro_resolutions: Default::default(),
1333 builtin_attrs: Default::default(),
1334 containers_deriving_copy: Default::default(),
1335 active_features: features
1336 .declared_lib_features
1338 .map(|(feat, ..)| *feat)
1339 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1341 variant_vis: Default::default(),
1342 lint_buffer: LintBuffer::default(),
1343 next_node_id: NodeId::from_u32(1),
1347 placeholder_field_indices: Default::default(),
1349 next_disambiguator: Default::default(),
1353 pub fn next_node_id(&mut self) -> NodeId {
1358 .expect("input too large; ran out of NodeIds");
1359 self.next_node_id = ast::NodeId::from_usize(next);
1363 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1364 &mut self.lint_buffer
1367 pub fn arenas() -> ResolverArenas<'a> {
1371 pub fn into_outputs(self) -> ResolverOutputs {
1372 let definitions = self.definitions;
1373 let extern_crate_map = self.extern_crate_map;
1374 let export_map = self.export_map;
1375 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1376 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1377 let glob_map = self.glob_map;
1379 definitions: definitions,
1380 cstore: Box::new(self.crate_loader.into_cstore()),
1384 maybe_unused_trait_imports,
1385 maybe_unused_extern_crates,
1386 extern_prelude: self
1389 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1394 pub fn clone_outputs(&self) -> ResolverOutputs {
1396 definitions: self.definitions.clone(),
1397 cstore: Box::new(self.cstore().clone()),
1398 extern_crate_map: self.extern_crate_map.clone(),
1399 export_map: self.export_map.clone(),
1400 glob_map: self.glob_map.clone(),
1401 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1402 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1403 extern_prelude: self
1406 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1411 pub fn cstore(&self) -> &CStore {
1412 self.crate_loader.cstore()
1415 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1416 self.non_macro_attrs[mark_used as usize].clone()
1419 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1421 MacroKind::Bang => self.dummy_ext_bang.clone(),
1422 MacroKind::Derive => self.dummy_ext_derive.clone(),
1423 MacroKind::Attr => self.non_macro_attr(true),
1427 /// Runs the function on each namespace.
1428 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1434 fn is_builtin_macro(&mut self, res: Res) -> bool {
1435 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1438 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1440 match ctxt.outer_expn().expn_data().macro_def_id {
1441 Some(def_id) => return def_id,
1442 None => ctxt.remove_mark(),
1447 /// Entry point to crate resolution.
1448 pub fn resolve_crate(&mut self, krate: &Crate) {
1449 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1451 ImportResolver { r: self }.finalize_imports();
1452 self.finalize_macro_resolutions();
1454 self.late_resolve_crate(krate);
1456 self.check_unused(krate);
1457 self.report_errors(krate);
1458 self.crate_loader.postprocess(krate);
1465 normal_ancestor_id: DefId,
1469 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1470 self.arenas.alloc_module(module)
1473 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1474 let ident = ident.normalize_to_macros_2_0();
1475 let disambiguator = if ident.name == kw::Underscore {
1476 self.underscore_disambiguator += 1;
1477 self.underscore_disambiguator
1481 BindingKey { ident, ns, disambiguator }
1484 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1485 if module.populate_on_access.get() {
1486 module.populate_on_access.set(false);
1487 self.build_reduced_graph_external(module);
1489 &module.lazy_resolutions
1496 ) -> &'a RefCell<NameResolution<'a>> {
1498 .resolutions(module)
1501 .or_insert_with(|| self.arenas.alloc_name_resolution())
1508 used_binding: &'a NameBinding<'a>,
1509 is_lexical_scope: bool,
1511 if let Some((b2, kind)) = used_binding.ambiguity {
1512 self.ambiguity_errors.push(AmbiguityError {
1517 misc1: AmbiguityErrorMisc::None,
1518 misc2: AmbiguityErrorMisc::None,
1521 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1522 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1523 // but not introduce it, as used if they are accessed from lexical scope.
1524 if is_lexical_scope {
1525 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1526 if let Some(crate_item) = entry.extern_crate_item {
1527 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1534 import.used.set(true);
1535 self.used_imports.insert((import.id, ns));
1536 self.add_to_glob_map(&import, ident);
1537 self.record_use(ident, ns, binding, false);
1542 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1543 if import.is_glob() {
1544 let def_id = self.local_def_id(import.id);
1545 self.glob_map.entry(def_id).or_default().insert(ident.name);
1549 /// A generic scope visitor.
1550 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1551 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1554 scope_set: ScopeSet,
1555 parent_scope: &ParentScope<'a>,
1557 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1559 // General principles:
1560 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1561 // built into the language or standard library. This way we can add new names into the
1562 // language or standard library without breaking user code.
1563 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1564 // Places to search (in order of decreasing priority):
1566 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1567 // (open set, not controlled).
1568 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1569 // (open, not controlled).
1570 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1571 // 4. Tool modules (closed, controlled right now, but not in the future).
1572 // 5. Standard library prelude (de-facto closed, controlled).
1573 // 6. Language prelude (closed, controlled).
1575 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1576 // (open set, not controlled).
1577 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1578 // (open, not controlled).
1579 // 3. Standard library prelude (de-facto closed, controlled).
1581 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1582 // are currently reported as errors. They should be higher in priority than preludes
1583 // and probably even names in modules according to the "general principles" above. They
1584 // also should be subject to restricted shadowing because are effectively produced by
1585 // derives (you need to resolve the derive first to add helpers into scope), but they
1586 // should be available before the derive is expanded for compatibility.
1587 // It's mess in general, so we are being conservative for now.
1588 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1589 // priority than prelude macros, but create ambiguities with macros in modules.
1590 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1591 // (open, not controlled). Have higher priority than prelude macros, but create
1592 // ambiguities with `macro_rules`.
1593 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1594 // 4a. User-defined prelude from macro-use
1595 // (open, the open part is from macro expansions, not controlled).
1596 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1597 // 4c. Standard library prelude (de-facto closed, controlled).
1598 // 6. Language prelude: builtin attributes (closed, controlled).
1600 let rust_2015 = ident.span.rust_2015();
1601 let (ns, macro_kind, is_absolute_path) = match scope_set {
1602 ScopeSet::All(ns, _) => (ns, None, false),
1603 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1604 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1606 // Jump out of trait or enum modules, they do not act as scopes.
1607 let module = parent_scope.module.nearest_item_scope();
1608 let mut scope = match ns {
1609 _ if is_absolute_path => Scope::CrateRoot,
1610 TypeNS | ValueNS => Scope::Module(module),
1611 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1613 let mut ident = ident.normalize_to_macros_2_0();
1614 let mut use_prelude = !module.no_implicit_prelude;
1617 let visit = match scope {
1618 // Derive helpers are not in scope when resolving derives in the same container.
1619 Scope::DeriveHelpers(expn_id) => {
1620 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1622 Scope::DeriveHelpersCompat => true,
1623 Scope::MacroRules(..) => true,
1624 Scope::CrateRoot => true,
1625 Scope::Module(..) => true,
1626 Scope::RegisteredAttrs => use_prelude,
1627 Scope::MacroUsePrelude => use_prelude || rust_2015,
1628 Scope::BuiltinAttrs => true,
1629 Scope::ExternPrelude => use_prelude || is_absolute_path,
1630 Scope::ToolPrelude => use_prelude,
1631 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1632 Scope::BuiltinTypes => true,
1636 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1637 return break_result;
1641 scope = match scope {
1642 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1643 // Derive helpers are not visible to code generated by bang or derive macros.
1644 let expn_data = expn_id.expn_data();
1645 match expn_data.kind {
1647 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1648 Scope::DeriveHelpersCompat
1650 _ => Scope::DeriveHelpers(expn_data.parent),
1653 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1654 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1655 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
1656 MacroRulesScope::Binding(binding) => {
1657 Scope::MacroRules(binding.parent_macro_rules_scope)
1659 MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
1660 self.output_macro_rules_scopes
1663 .unwrap_or(self.invocation_parent_scopes[&invoc_id].macro_rules),
1665 MacroRulesScope::Empty => Scope::Module(module),
1667 Scope::CrateRoot => match ns {
1669 ident.span.adjust(ExpnId::root());
1670 Scope::ExternPrelude
1672 ValueNS | MacroNS => break,
1674 Scope::Module(module) => {
1675 use_prelude = !module.no_implicit_prelude;
1676 match self.hygienic_lexical_parent(module, &mut ident.span) {
1677 Some(parent_module) => Scope::Module(parent_module),
1679 ident.span.adjust(ExpnId::root());
1681 TypeNS => Scope::ExternPrelude,
1682 ValueNS => Scope::StdLibPrelude,
1683 MacroNS => Scope::RegisteredAttrs,
1688 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1689 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1690 Scope::BuiltinAttrs => break, // nowhere else to search
1691 Scope::ExternPrelude if is_absolute_path => break,
1692 Scope::ExternPrelude => Scope::ToolPrelude,
1693 Scope::ToolPrelude => Scope::StdLibPrelude,
1694 Scope::StdLibPrelude => match ns {
1695 TypeNS => Scope::BuiltinTypes,
1696 ValueNS => break, // nowhere else to search
1697 MacroNS => Scope::BuiltinAttrs,
1699 Scope::BuiltinTypes => break, // nowhere else to search
1706 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1707 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1708 /// `ident` in the first scope that defines it (or None if no scopes define it).
1710 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1711 /// the items are defined in the block. For example,
1714 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1717 /// g(); // This resolves to the local variable `g` since it shadows the item.
1721 /// Invariant: This must only be called during main resolution, not during
1722 /// import resolution.
1723 fn resolve_ident_in_lexical_scope(
1727 parent_scope: &ParentScope<'a>,
1728 record_used_id: Option<NodeId>,
1731 ) -> Option<LexicalScopeBinding<'a>> {
1732 assert!(ns == TypeNS || ns == ValueNS);
1733 if ident.name == kw::Invalid {
1734 return Some(LexicalScopeBinding::Res(Res::Err));
1736 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1737 // FIXME(jseyfried) improve `Self` hygiene
1738 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1739 (empty_span, empty_span)
1740 } else if ns == TypeNS {
1741 let normalized_span = ident.span.normalize_to_macros_2_0();
1742 (normalized_span, normalized_span)
1744 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1746 ident.span = general_span;
1747 let normalized_ident = Ident { span: normalized_span, ..ident };
1749 // Walk backwards up the ribs in scope.
1750 let record_used = record_used_id.is_some();
1751 let mut module = self.graph_root;
1752 for i in (0..ribs.len()).rev() {
1753 debug!("walk rib\n{:?}", ribs[i].bindings);
1754 // Use the rib kind to determine whether we are resolving parameters
1755 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1756 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1757 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1758 // The ident resolves to a type parameter or local variable.
1759 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1769 module = match ribs[i].kind {
1770 ModuleRibKind(module) => module,
1771 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1772 // If an invocation of this macro created `ident`, give up on `ident`
1773 // and switch to `ident`'s source from the macro definition.
1774 ident.span.remove_mark();
1780 let item = self.resolve_ident_in_module_unadjusted(
1781 ModuleOrUniformRoot::Module(module),
1788 if let Ok(binding) = item {
1789 // The ident resolves to an item.
1790 return Some(LexicalScopeBinding::Item(binding));
1794 ModuleKind::Block(..) => {} // We can see through blocks
1799 ident = normalized_ident;
1800 let mut poisoned = None;
1802 let opt_module = if let Some(node_id) = record_used_id {
1803 self.hygienic_lexical_parent_with_compatibility_fallback(
1810 self.hygienic_lexical_parent(module, &mut ident.span)
1812 module = unwrap_or!(opt_module, break);
1813 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1814 let result = self.resolve_ident_in_module_unadjusted(
1815 ModuleOrUniformRoot::Module(module),
1818 adjusted_parent_scope,
1825 if let Some(node_id) = poisoned {
1826 self.lint_buffer.buffer_lint_with_diagnostic(
1827 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1830 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1831 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1834 return Some(LexicalScopeBinding::Item(binding));
1836 Err(Determined) => continue,
1837 Err(Undetermined) => {
1838 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1843 if !module.no_implicit_prelude {
1844 ident.span.adjust(ExpnId::root());
1846 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1847 return Some(LexicalScopeBinding::Item(binding));
1849 if let Some(ident) = self.registered_tools.get(&ident) {
1851 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1852 .to_name_binding(self.arenas);
1853 return Some(LexicalScopeBinding::Item(binding));
1856 if let Some(prelude) = self.prelude {
1857 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1858 ModuleOrUniformRoot::Module(prelude),
1865 return Some(LexicalScopeBinding::Item(binding));
1871 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1873 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1874 .to_name_binding(self.arenas);
1875 return Some(LexicalScopeBinding::Item(binding));
1882 fn hygienic_lexical_parent(
1886 ) -> Option<Module<'a>> {
1887 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1888 return Some(self.macro_def_scope(span.remove_mark()));
1891 if let ModuleKind::Block(..) = module.kind {
1892 return Some(module.parent.unwrap().nearest_item_scope());
1898 fn hygienic_lexical_parent_with_compatibility_fallback(
1903 poisoned: &mut Option<NodeId>,
1904 ) -> Option<Module<'a>> {
1905 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1909 // We need to support the next case under a deprecation warning
1912 // ---- begin: this comes from a proc macro derive
1913 // mod implementation_details {
1914 // // Note that `MyStruct` is not in scope here.
1915 // impl SomeTrait for MyStruct { ... }
1919 // So we have to fall back to the module's parent during lexical resolution in this case.
1920 if let Some(parent) = module.parent {
1921 // Inner module is inside the macro, parent module is outside of the macro.
1922 if module.expansion != parent.expansion
1923 && module.expansion.is_descendant_of(parent.expansion)
1925 // The macro is a proc macro derive
1926 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
1927 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1928 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1929 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1930 *poisoned = Some(node_id);
1931 return module.parent;
1942 fn resolve_ident_in_module(
1944 module: ModuleOrUniformRoot<'a>,
1947 parent_scope: &ParentScope<'a>,
1950 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1951 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1952 .map_err(|(determinacy, _)| determinacy)
1955 fn resolve_ident_in_module_ext(
1957 module: ModuleOrUniformRoot<'a>,
1960 parent_scope: &ParentScope<'a>,
1963 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1964 let tmp_parent_scope;
1965 let mut adjusted_parent_scope = parent_scope;
1967 ModuleOrUniformRoot::Module(m) => {
1968 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
1970 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1971 adjusted_parent_scope = &tmp_parent_scope;
1974 ModuleOrUniformRoot::ExternPrelude => {
1975 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
1977 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1981 self.resolve_ident_in_module_unadjusted_ext(
1985 adjusted_parent_scope,
1992 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1993 debug!("resolve_crate_root({:?})", ident);
1994 let mut ctxt = ident.span.ctxt();
1995 let mark = if ident.name == kw::DollarCrate {
1996 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1997 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1998 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
1999 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2000 // definitions actually produced by `macro` and `macro` definitions produced by
2001 // `macro_rules!`, but at least such configurations are not stable yet.
2002 ctxt = ctxt.normalize_to_macro_rules();
2004 "resolve_crate_root: marks={:?}",
2005 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2007 let mut iter = ctxt.marks().into_iter().rev().peekable();
2008 let mut result = None;
2009 // Find the last opaque mark from the end if it exists.
2010 while let Some(&(mark, transparency)) = iter.peek() {
2011 if transparency == Transparency::Opaque {
2012 result = Some(mark);
2019 "resolve_crate_root: found opaque mark {:?} {:?}",
2021 result.map(|r| r.expn_data())
2023 // Then find the last semi-transparent mark from the end if it exists.
2024 for (mark, transparency) in iter {
2025 if transparency == Transparency::SemiTransparent {
2026 result = Some(mark);
2032 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2034 result.map(|r| r.expn_data())
2038 debug!("resolve_crate_root: not DollarCrate");
2039 ctxt = ctxt.normalize_to_macros_2_0();
2040 ctxt.adjust(ExpnId::root())
2042 let module = match mark {
2043 Some(def) => self.macro_def_scope(def),
2046 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2049 return self.graph_root;
2052 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id });
2054 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2063 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2064 let mut module = self.get_module(module.normal_ancestor_id);
2065 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2066 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2067 module = self.get_module(parent.normal_ancestor_id);
2075 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2076 parent_scope: &ParentScope<'a>,
2079 crate_lint: CrateLint,
2080 ) -> PathResult<'a> {
2081 self.resolve_path_with_ribs(
2092 fn resolve_path_with_ribs(
2095 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2096 parent_scope: &ParentScope<'a>,
2099 crate_lint: CrateLint,
2100 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2101 ) -> PathResult<'a> {
2102 let mut module = None;
2103 let mut allow_super = true;
2104 let mut second_binding = None;
2107 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2108 path_span={:?}, crate_lint={:?})",
2109 path, opt_ns, record_used, path_span, crate_lint,
2112 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2113 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2114 let record_segment_res = |this: &mut Self, res| {
2116 if let Some(id) = id {
2117 if !this.partial_res_map.contains_key(&id) {
2118 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2119 this.record_partial_res(id, PartialRes::new(res));
2125 let is_last = i == path.len() - 1;
2126 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2127 let name = ident.name;
2129 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2132 if allow_super && name == kw::Super {
2133 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2134 let self_module = match i {
2135 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2137 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2141 if let Some(self_module) = self_module {
2142 if let Some(parent) = self_module.parent {
2143 module = Some(ModuleOrUniformRoot::Module(
2144 self.resolve_self(&mut ctxt, parent),
2149 let msg = "there are too many leading `super` keywords".to_string();
2150 return PathResult::Failed {
2154 is_error_from_last_segment: false,
2158 if name == kw::SelfLower {
2159 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2160 module = Some(ModuleOrUniformRoot::Module(
2161 self.resolve_self(&mut ctxt, parent_scope.module),
2165 if name == kw::PathRoot && ident.span.rust_2018() {
2166 module = Some(ModuleOrUniformRoot::ExternPrelude);
2169 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2170 // `::a::b` from 2015 macro on 2018 global edition
2171 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2174 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2175 // `::a::b`, `crate::a::b` or `$crate::a::b`
2176 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2182 // Report special messages for path segment keywords in wrong positions.
2183 if ident.is_path_segment_keyword() && i != 0 {
2184 let name_str = if name == kw::PathRoot {
2185 "crate root".to_string()
2187 format!("`{}`", name)
2189 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2190 format!("global paths cannot start with {}", name_str)
2192 format!("{} in paths can only be used in start position", name_str)
2194 return PathResult::Failed {
2198 is_error_from_last_segment: false,
2202 enum FindBindingResult<'a> {
2203 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2204 PathResult(PathResult<'a>),
2206 let find_binding_in_ns = |this: &mut Self, ns| {
2207 let binding = if let Some(module) = module {
2208 this.resolve_ident_in_module(
2216 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2217 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2218 this.early_resolve_ident_in_lexical_scope(
2227 let record_used_id = if record_used {
2228 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2232 match this.resolve_ident_in_lexical_scope(
2240 // we found a locally-imported or available item/module
2241 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2242 // we found a local variable or type param
2243 Some(LexicalScopeBinding::Res(res))
2244 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2246 record_segment_res(this, res);
2247 return FindBindingResult::PathResult(PathResult::NonModule(
2248 PartialRes::with_unresolved_segments(res, path.len() - 1),
2251 _ => Err(Determinacy::determined(record_used)),
2254 FindBindingResult::Binding(binding)
2256 let binding = match find_binding_in_ns(self, ns) {
2257 FindBindingResult::PathResult(x) => return x,
2258 FindBindingResult::Binding(binding) => binding,
2263 second_binding = Some(binding);
2265 let res = binding.res();
2266 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2267 if let Some(next_module) = binding.module() {
2268 module = Some(ModuleOrUniformRoot::Module(next_module));
2269 record_segment_res(self, res);
2270 } else if res == Res::ToolMod && i + 1 != path.len() {
2271 if binding.is_import() {
2275 "cannot use a tool module through an import",
2277 .span_note(binding.span, "the tool module imported here")
2280 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2281 return PathResult::NonModule(PartialRes::new(res));
2282 } else if res == Res::Err {
2283 return PathResult::NonModule(PartialRes::new(Res::Err));
2284 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2285 self.lint_if_path_starts_with_module(
2291 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2296 let label = format!(
2297 "`{}` is {} {}, not a module",
2303 return PathResult::Failed {
2307 is_error_from_last_segment: is_last,
2311 Err(Undetermined) => return PathResult::Indeterminate,
2312 Err(Determined) => {
2313 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2314 if opt_ns.is_some() && !module.is_normal() {
2315 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2316 module.res().unwrap(),
2321 let module_res = match module {
2322 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2325 let (label, suggestion) = if module_res == self.graph_root.res() {
2326 let is_mod = |res| match res {
2327 Res::Def(DefKind::Mod, _) => true,
2330 let mut candidates =
2331 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
2332 candidates.sort_by_cached_key(|c| {
2333 (c.path.segments.len(), pprust::path_to_string(&c.path))
2335 if let Some(candidate) = candidates.get(0) {
2337 String::from("unresolved import"),
2339 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2340 String::from("a similar path exists"),
2341 Applicability::MaybeIncorrect,
2345 (format!("maybe a missing crate `{}`?", ident), None)
2348 (format!("use of undeclared type or module `{}`", ident), None)
2351 format!("could not find `{}` in `{}`", ident, path[i - 1].ident);
2352 if ns == TypeNS || ns == ValueNS {
2353 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2354 if let FindBindingResult::Binding(Ok(binding)) =
2355 find_binding_in_ns(self, ns_to_try)
2357 let mut found = |what| {
2359 "expected {}, found {} `{}` in `{}`",
2366 if binding.module().is_some() {
2369 match binding.res() {
2370 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2371 _ => found(ns_to_try.descr()),
2378 return PathResult::Failed {
2382 is_error_from_last_segment: is_last,
2388 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2390 PathResult::Module(match module {
2391 Some(module) => module,
2392 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2393 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2397 fn lint_if_path_starts_with_module(
2399 crate_lint: CrateLint,
2402 second_binding: Option<&NameBinding<'_>>,
2404 let (diag_id, diag_span) = match crate_lint {
2405 CrateLint::No => return,
2406 CrateLint::SimplePath(id) => (id, path_span),
2407 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2408 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2411 let first_name = match path.get(0) {
2412 // In the 2018 edition this lint is a hard error, so nothing to do
2413 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2417 // We're only interested in `use` paths which should start with
2418 // `{{root}}` currently.
2419 if first_name != kw::PathRoot {
2424 // If this import looks like `crate::...` it's already good
2425 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2426 // Otherwise go below to see if it's an extern crate
2428 // If the path has length one (and it's `PathRoot` most likely)
2429 // then we don't know whether we're gonna be importing a crate or an
2430 // item in our crate. Defer this lint to elsewhere
2434 // If the first element of our path was actually resolved to an
2435 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2436 // warning, this looks all good!
2437 if let Some(binding) = second_binding {
2438 if let NameBindingKind::Import { import, .. } = binding.kind {
2439 // Careful: we still want to rewrite paths from renamed extern crates.
2440 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2446 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2447 self.lint_buffer.buffer_lint_with_diagnostic(
2448 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2451 "absolute paths must start with `self`, `super`, \
2452 `crate`, or an external crate name in the 2018 edition",
2457 // Validate a local resolution (from ribs).
2458 fn validate_res_from_ribs(
2465 all_ribs: &[Rib<'a>],
2467 debug!("validate_res_from_ribs({:?})", res);
2468 let ribs = &all_ribs[rib_index + 1..];
2470 // An invalid forward use of a type parameter from a previous default.
2471 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2473 let res_error = if rib_ident.name == kw::SelfUpper {
2474 ResolutionError::SelfInTyParamDefault
2476 ResolutionError::ForwardDeclaredTyParam
2478 self.report_error(span, res_error);
2480 assert_eq!(res, Res::Err);
2486 use ResolutionError::*;
2487 let mut res_err = None;
2492 | ClosureOrAsyncRibKind
2494 | MacroDefinition(..)
2495 | ForwardTyParamBanRibKind => {
2496 // Nothing to do. Continue.
2498 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2499 // This was an attempt to access an upvar inside a
2500 // named function item. This is not allowed, so we
2503 // We don't immediately trigger a resolve error, because
2504 // we want certain other resolution errors (namely those
2505 // emitted for `ConstantItemRibKind` below) to take
2507 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2510 ConstantItemRibKind => {
2511 // Still doesn't deal with upvars
2513 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2517 ConstParamTyRibKind => {
2519 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2525 if let Some(res_err) = res_err {
2526 self.report_error(span, res_err);
2530 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2531 let mut in_ty_param_default = false;
2533 let has_generic_params = match rib.kind {
2535 | ClosureOrAsyncRibKind
2538 | MacroDefinition(..) => {
2539 // Nothing to do. Continue.
2543 // We only forbid constant items if we are inside of type defaults,
2544 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2545 ForwardTyParamBanRibKind => {
2546 in_ty_param_default = true;
2549 ConstantItemRibKind => {
2550 if in_ty_param_default {
2554 ResolutionError::ParamInAnonConstInTyDefault(
2565 // This was an attempt to use a type parameter outside its scope.
2566 ItemRibKind(has_generic_params) => has_generic_params,
2567 FnItemRibKind => HasGenericParams::Yes,
2568 ConstParamTyRibKind => {
2572 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2582 ResolutionError::GenericParamsFromOuterFunction(
2591 Res::Def(DefKind::ConstParam, _) => {
2592 let mut ribs = ribs.iter().peekable();
2593 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2594 // When declaring const parameters inside function signatures, the first rib
2595 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2596 // (spuriously) conflicting with the const param.
2600 let mut in_ty_param_default = false;
2602 let has_generic_params = match rib.kind {
2604 | ClosureOrAsyncRibKind
2607 | MacroDefinition(..) => continue,
2609 // We only forbid constant items if we are inside of type defaults,
2610 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2611 ForwardTyParamBanRibKind => {
2612 in_ty_param_default = true;
2615 ConstantItemRibKind => {
2616 if in_ty_param_default {
2620 ResolutionError::ParamInAnonConstInTyDefault(
2631 ItemRibKind(has_generic_params) => has_generic_params,
2632 FnItemRibKind => HasGenericParams::Yes,
2633 ConstParamTyRibKind => {
2637 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2644 // This was an attempt to use a const parameter outside its scope.
2648 ResolutionError::GenericParamsFromOuterFunction(
2662 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2663 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2664 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2665 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2669 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2670 vis.is_accessible_from(module.normal_ancestor_id, self)
2673 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2674 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2675 if !ptr::eq(module, old_module) {
2676 span_bug!(binding.span, "parent module is reset for binding");
2681 fn disambiguate_macro_rules_vs_modularized(
2683 macro_rules: &'a NameBinding<'a>,
2684 modularized: &'a NameBinding<'a>,
2686 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2687 // is disambiguated to mitigate regressions from macro modularization.
2688 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2690 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2691 self.binding_parent_modules.get(&PtrKey(modularized)),
2693 (Some(macro_rules), Some(modularized)) => {
2694 macro_rules.normal_ancestor_id == modularized.normal_ancestor_id
2695 && modularized.is_ancestor_of(macro_rules)
2701 fn report_errors(&mut self, krate: &Crate) {
2702 self.report_with_use_injections(krate);
2704 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2705 let msg = "macro-expanded `macro_export` macros from the current crate \
2706 cannot be referred to by absolute paths";
2707 self.lint_buffer.buffer_lint_with_diagnostic(
2708 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2712 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2716 for ambiguity_error in &self.ambiguity_errors {
2717 self.report_ambiguity_error(ambiguity_error);
2720 let mut reported_spans = FxHashSet::default();
2721 for error in &self.privacy_errors {
2722 if reported_spans.insert(error.dedup_span) {
2723 self.report_privacy_error(error);
2728 fn report_with_use_injections(&mut self, krate: &Crate) {
2729 for UseError { mut err, candidates, def_id, instead, suggestion } in
2730 self.use_injections.drain(..)
2732 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2733 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2737 if !candidates.is_empty() {
2738 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2739 } else if let Some((span, msg, sugg, appl)) = suggestion {
2740 err.span_suggestion(span, msg, sugg, appl);
2746 fn report_conflict<'b>(
2751 new_binding: &NameBinding<'b>,
2752 old_binding: &NameBinding<'b>,
2754 // Error on the second of two conflicting names
2755 if old_binding.span.lo() > new_binding.span.lo() {
2756 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2759 let container = match parent.kind {
2760 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2761 ModuleKind::Block(..) => "block",
2764 let old_noun = match old_binding.is_import() {
2766 false => "definition",
2769 let new_participle = match new_binding.is_import() {
2775 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2777 if let Some(s) = self.name_already_seen.get(&name) {
2783 let old_kind = match (ns, old_binding.module()) {
2784 (ValueNS, _) => "value",
2785 (MacroNS, _) => "macro",
2786 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2787 (TypeNS, Some(module)) if module.is_normal() => "module",
2788 (TypeNS, Some(module)) if module.is_trait() => "trait",
2789 (TypeNS, _) => "type",
2792 let msg = format!("the name `{}` is defined multiple times", name);
2794 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2795 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2796 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2797 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2798 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2800 _ => match (old_binding.is_import(), new_binding.is_import()) {
2801 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2802 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2803 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2808 "`{}` must be defined only once in the {} namespace of this {}",
2814 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2816 self.session.source_map().guess_head_span(old_binding.span),
2817 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2820 // See https://github.com/rust-lang/rust/issues/32354
2821 use NameBindingKind::Import;
2822 let import = match (&new_binding.kind, &old_binding.kind) {
2823 // If there are two imports where one or both have attributes then prefer removing the
2824 // import without attributes.
2825 (Import { import: new, .. }, Import { import: old, .. })
2827 !new_binding.span.is_dummy()
2828 && !old_binding.span.is_dummy()
2829 && (new.has_attributes || old.has_attributes)
2832 if old.has_attributes {
2833 Some((new, new_binding.span, true))
2835 Some((old, old_binding.span, true))
2838 // Otherwise prioritize the new binding.
2839 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
2840 Some((import, new_binding.span, other.is_import()))
2842 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
2843 Some((import, old_binding.span, other.is_import()))
2848 // Check if the target of the use for both bindings is the same.
2849 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2850 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2852 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2853 // Only suggest removing an import if both bindings are to the same def, if both spans
2854 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2855 // been introduced by a item.
2856 let should_remove_import = duplicate
2858 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2861 Some((import, span, true)) if should_remove_import && import.is_nested() => {
2862 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
2864 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
2865 // Simple case - remove the entire import. Due to the above match arm, this can
2866 // only be a single use so just remove it entirely.
2867 err.tool_only_span_suggestion(
2868 import.use_span_with_attributes,
2869 "remove unnecessary import",
2871 Applicability::MaybeIncorrect,
2874 Some((import, span, _)) => {
2875 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
2881 self.name_already_seen.insert(name, span);
2884 /// This function adds a suggestion to change the binding name of a new import that conflicts
2885 /// with an existing import.
2887 /// ```text,ignore (diagnostic)
2888 /// help: you can use `as` to change the binding name of the import
2890 /// LL | use foo::bar as other_bar;
2891 /// | ^^^^^^^^^^^^^^^^^^^^^
2893 fn add_suggestion_for_rename_of_use(
2895 err: &mut DiagnosticBuilder<'_>,
2897 import: &Import<'_>,
2900 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2901 format!("Other{}", name)
2903 format!("other_{}", name)
2906 let mut suggestion = None;
2908 ImportKind::Single { type_ns_only: true, .. } => {
2909 suggestion = Some(format!("self as {}", suggested_name))
2911 ImportKind::Single { source, .. } => {
2913 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2915 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2916 if pos <= snippet.len() {
2917 suggestion = Some(format!(
2921 if snippet.ends_with(';') { ";" } else { "" }
2927 ImportKind::ExternCrate { source, target, .. } => {
2928 suggestion = Some(format!(
2929 "extern crate {} as {};",
2930 source.unwrap_or(target.name),
2934 _ => unreachable!(),
2937 let rename_msg = "you can use `as` to change the binding name of the import";
2938 if let Some(suggestion) = suggestion {
2939 err.span_suggestion(
2943 Applicability::MaybeIncorrect,
2946 err.span_label(binding_span, rename_msg);
2950 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2951 /// nested. In the following example, this function will be invoked to remove the `a` binding
2952 /// in the second use statement:
2954 /// ```ignore (diagnostic)
2955 /// use issue_52891::a;
2956 /// use issue_52891::{d, a, e};
2959 /// The following suggestion will be added:
2961 /// ```ignore (diagnostic)
2962 /// use issue_52891::{d, a, e};
2963 /// ^-- help: remove unnecessary import
2966 /// If the nested use contains only one import then the suggestion will remove the entire
2969 /// It is expected that the provided import is nested - this isn't checked by the
2970 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2971 /// as characters expected by span manipulations won't be present.
2972 fn add_suggestion_for_duplicate_nested_use(
2974 err: &mut DiagnosticBuilder<'_>,
2975 import: &Import<'_>,
2978 assert!(import.is_nested());
2979 let message = "remove unnecessary import";
2981 // Two examples will be used to illustrate the span manipulations we're doing:
2983 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
2984 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
2985 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
2986 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
2988 let (found_closing_brace, span) =
2989 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
2991 // If there was a closing brace then identify the span to remove any trailing commas from
2992 // previous imports.
2993 if found_closing_brace {
2994 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
2995 err.tool_only_span_suggestion(
2999 Applicability::MaybeIncorrect,
3002 // Remove the entire line if we cannot extend the span back, this indicates a
3003 // `issue_52891::{self}` case.
3004 err.span_suggestion(
3005 import.use_span_with_attributes,
3008 Applicability::MaybeIncorrect,
3015 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3018 fn extern_prelude_get(
3022 ) -> Option<&'a NameBinding<'a>> {
3023 if ident.is_path_segment_keyword() {
3024 // Make sure `self`, `super` etc produce an error when passed to here.
3027 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3028 if let Some(binding) = entry.extern_crate_item {
3029 if !speculative && entry.introduced_by_item {
3030 self.record_use(ident, TypeNS, binding, false);
3034 let crate_id = if !speculative {
3035 self.crate_loader.process_path_extern(ident.name, ident.span)
3037 self.crate_loader.maybe_process_path_extern(ident.name)?
3039 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3041 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3042 .to_name_binding(self.arenas),
3048 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3049 /// isn't something that can be returned because it can't be made to live that long,
3050 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3051 /// just that an error occurred.
3052 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3053 pub fn resolve_str_path_error(
3059 ) -> Result<(ast::Path, Res), ()> {
3060 let path = if path_str.starts_with("::") {
3063 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3064 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3065 .map(|i| self.new_ast_path_segment(i))
3073 .map(Ident::from_str)
3074 .map(|i| self.new_ast_path_segment(i))
3078 let module = self.get_module(module_id);
3079 let parent_scope = &ParentScope::module(module);
3080 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3084 // Resolve a path passed from rustdoc or HIR lowering.
3085 fn resolve_ast_path(
3089 parent_scope: &ParentScope<'a>,
3090 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3091 match self.resolve_path(
3092 &Segment::from_path(path),
3099 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3100 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3101 Ok(path_res.base_res())
3103 PathResult::NonModule(..) => Err((
3105 ResolutionError::FailedToResolve {
3106 label: String::from("type-relative paths are not supported in this context"),
3110 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3111 PathResult::Failed { span, label, suggestion, .. } => {
3112 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3117 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3118 let mut seg = ast::PathSegment::from_ident(ident);
3119 seg.id = self.next_node_id();
3124 pub fn graph_root(&self) -> Module<'a> {
3129 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3133 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3135 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3136 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3140 fn names_to_string(names: &[Symbol]) -> String {
3141 let mut result = String::new();
3142 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3144 result.push_str("::");
3146 if Ident::with_dummy_span(*name).is_raw_guess() {
3147 result.push_str("r#");
3149 result.push_str(&name.as_str());
3154 fn path_names_to_string(path: &Path) -> String {
3155 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3158 /// A somewhat inefficient routine to obtain the name of a module.
3159 fn module_to_string(module: Module<'_>) -> Option<String> {
3160 let mut names = Vec::new();
3162 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3163 if let ModuleKind::Def(.., name) = module.kind {
3164 if let Some(parent) = module.parent {
3166 collect_mod(names, parent);
3169 names.push(Symbol::intern("<opaque>"));
3170 collect_mod(names, module.parent.unwrap());
3173 collect_mod(&mut names, module);
3175 if names.is_empty() {
3179 Some(names_to_string(&names))
3182 #[derive(Copy, Clone, Debug)]
3184 /// Do not issue the lint.
3187 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3188 /// In this case, we can take the span of that path.
3191 /// This lint comes from a `use` statement. In this case, what we
3192 /// care about really is the *root* `use` statement; e.g., if we
3193 /// have nested things like `use a::{b, c}`, we care about the
3195 UsePath { root_id: NodeId, root_span: Span },
3197 /// This is the "trait item" from a fully qualified path. For example,
3198 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3199 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3200 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3204 fn node_id(&self) -> Option<NodeId> {
3206 CrateLint::No => None,
3207 CrateLint::SimplePath(id)
3208 | CrateLint::UsePath { root_id: id, .. }
3209 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3214 pub fn provide(providers: &mut Providers) {
3215 late::lifetimes::provide(providers);