1 //! This crate is responsible for the part of name resolution that doesn't require type checker.
3 //! Module structure of the crate is built here.
4 //! Paths in macros, imports, expressions, types, patterns are resolved here.
5 //! Label and lifetime names are resolved here as well.
7 //! Type-relative name resolution (methods, fields, associated items) happens in `rustc_typeck`.
9 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
10 #![feature(box_patterns)]
11 #![feature(drain_filter)]
12 #![feature(bool_to_option)]
13 #![feature(crate_visibility_modifier)]
14 #![feature(if_let_guard)]
15 #![feature(let_chains)]
17 #![feature(never_type)]
19 #![recursion_limit = "256"]
20 #![allow(rustdoc::private_intra_doc_links)]
21 #![allow(rustc::potential_query_instability)]
26 pub use rustc_hir::def::{Namespace, PerNS};
28 use rustc_arena::{DroplessArena, TypedArena};
29 use rustc_ast::node_id::NodeMap;
30 use rustc_ast::{self as ast, NodeId, CRATE_NODE_ID};
31 use rustc_ast::{AngleBracketedArg, Crate, Expr, ExprKind, GenericArg, GenericArgs, LitKind, Path};
32 use rustc_ast_lowering::{LifetimeRes, ResolverAstLowering};
33 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
34 use rustc_data_structures::intern::Interned;
35 use rustc_data_structures::sync::Lrc;
36 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed};
37 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
38 use rustc_hir::def::Namespace::*;
39 use rustc_hir::def::{self, CtorOf, DefKind, PartialRes};
40 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
41 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
42 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
43 use rustc_hir::TraitCandidate;
44 use rustc_index::vec::IndexVec;
45 use rustc_metadata::creader::{CStore, CrateLoader};
46 use rustc_middle::metadata::ModChild;
47 use rustc_middle::middle::privacy::AccessLevels;
48 use rustc_middle::span_bug;
49 use rustc_middle::ty::query::Providers;
50 use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, ResolverOutputs};
51 use rustc_query_system::ich::StableHashingContext;
52 use rustc_session::cstore::{CrateStore, MetadataLoaderDyn};
53 use rustc_session::lint::LintBuffer;
54 use rustc_session::Session;
55 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind, SyntaxContext, Transparency};
56 use rustc_span::source_map::Spanned;
57 use rustc_span::symbol::{kw, sym, Ident, Symbol};
58 use rustc_span::{Span, DUMMY_SP};
60 use smallvec::{smallvec, SmallVec};
61 use std::cell::{Cell, RefCell};
62 use std::collections::BTreeSet;
63 use std::{cmp, fmt, mem, ptr};
66 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
67 use imports::{Import, ImportKind, ImportResolver, NameResolution};
68 use late::{HasGenericParams, PathSource};
69 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
71 use crate::access_levels::AccessLevelsVisitor;
73 type Res = def::Res<NodeId>;
76 mod build_reduced_graph;
90 #[derive(Copy, Clone, PartialEq, Debug)]
91 pub enum Determinacy {
97 fn determined(determined: bool) -> Determinacy {
98 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
102 /// A specific scope in which a name can be looked up.
103 /// This enum is currently used only for early resolution (imports and macros),
104 /// but not for late resolution yet.
105 #[derive(Clone, Copy)]
107 DeriveHelpers(LocalExpnId),
109 MacroRules(MacroRulesScopeRef<'a>),
111 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
112 // lint if it should be reported.
113 Module(Module<'a>, Option<NodeId>),
123 /// Names from different contexts may want to visit different subsets of all specific scopes
124 /// with different restrictions when looking up the resolution.
125 /// This enum is currently used only for early resolution (imports and macros),
126 /// but not for late resolution yet.
127 #[derive(Clone, Copy)]
129 /// All scopes with the given namespace.
130 All(Namespace, /*is_import*/ bool),
131 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
132 AbsolutePath(Namespace),
133 /// All scopes with macro namespace and the given macro kind restriction.
135 /// All scopes with the given namespace, used for partially performing late resolution.
136 /// The node id enables lints and is used for reporting them.
137 Late(Namespace, Module<'a>, Option<NodeId>),
140 /// Everything you need to know about a name's location to resolve it.
141 /// Serves as a starting point for the scope visitor.
142 /// This struct is currently used only for early resolution (imports and macros),
143 /// but not for late resolution yet.
144 #[derive(Clone, Copy, Debug)]
145 pub struct ParentScope<'a> {
147 expansion: LocalExpnId,
148 macro_rules: MacroRulesScopeRef<'a>,
149 derives: &'a [ast::Path],
152 impl<'a> ParentScope<'a> {
153 /// Creates a parent scope with the passed argument used as the module scope component,
154 /// and other scope components set to default empty values.
155 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
158 expansion: LocalExpnId::ROOT,
159 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
165 #[derive(Copy, Debug, Clone)]
166 enum ImplTraitContext {
168 Universal(LocalDefId),
172 struct BindingError {
174 origin: BTreeSet<Span>,
175 target: BTreeSet<Span>,
179 impl PartialOrd for BindingError {
180 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
181 Some(self.cmp(other))
185 impl PartialEq for BindingError {
186 fn eq(&self, other: &BindingError) -> bool {
187 self.name == other.name
191 impl Ord for BindingError {
192 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
193 self.name.cmp(&other.name)
197 enum ResolutionError<'a> {
198 /// Error E0401: can't use type or const parameters from outer function.
199 GenericParamsFromOuterFunction(Res, HasGenericParams),
200 /// Error E0403: the name is already used for a type or const parameter in this generic
202 NameAlreadyUsedInParameterList(Symbol, Span),
203 /// Error E0407: method is not a member of trait.
204 MethodNotMemberOfTrait(Ident, String, Option<Symbol>),
205 /// Error E0437: type is not a member of trait.
206 TypeNotMemberOfTrait(Ident, String, Option<Symbol>),
207 /// Error E0438: const is not a member of trait.
208 ConstNotMemberOfTrait(Ident, String, Option<Symbol>),
209 /// Error E0408: variable `{}` is not bound in all patterns.
210 VariableNotBoundInPattern(BindingError, ParentScope<'a>),
211 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
212 VariableBoundWithDifferentMode(Symbol, Span),
213 /// Error E0415: identifier is bound more than once in this parameter list.
214 IdentifierBoundMoreThanOnceInParameterList(Symbol),
215 /// Error E0416: identifier is bound more than once in the same pattern.
216 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
217 /// Error E0426: use of undeclared label.
218 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
219 /// Error E0429: `self` imports are only allowed within a `{ }` list.
220 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
221 /// Error E0430: `self` import can only appear once in the list.
222 SelfImportCanOnlyAppearOnceInTheList,
223 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
224 SelfImportOnlyInImportListWithNonEmptyPrefix,
225 /// Error E0433: failed to resolve.
226 FailedToResolve { label: String, suggestion: Option<Suggestion> },
227 /// Error E0434: can't capture dynamic environment in a fn item.
228 CannotCaptureDynamicEnvironmentInFnItem,
229 /// Error E0435: attempt to use a non-constant value in a constant.
230 AttemptToUseNonConstantValueInConstant(
232 /* suggestion */ &'static str,
233 /* current */ &'static str,
235 /// Error E0530: `X` bindings cannot shadow `Y`s.
236 BindingShadowsSomethingUnacceptable {
237 shadowing_binding_descr: &'static str,
239 participle: &'static str,
240 article: &'static str,
241 shadowed_binding_descr: &'static str,
242 shadowed_binding_span: Span,
244 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
245 ForwardDeclaredGenericParam,
246 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
247 ParamInTyOfConstParam(Symbol),
248 /// generic parameters must not be used inside const evaluations.
250 /// This error is only emitted when using `min_const_generics`.
251 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
252 /// Error E0735: generic parameters with a default cannot use `Self`
253 SelfInGenericParamDefault,
254 /// Error E0767: use of unreachable label
255 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
256 /// Error E0323, E0324, E0325: mismatch between trait item and impl item.
261 trait_item_span: Span,
262 code: rustc_errors::DiagnosticId,
264 /// Inline asm `sym` operand must refer to a `fn` or `static`.
268 enum VisResolutionError<'a> {
269 Relative2018(Span, &'a ast::Path),
271 FailedToResolve(Span, String, Option<Suggestion>),
272 ExpectedFound(Span, String, Res),
277 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
278 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
279 #[derive(Clone, Copy, Debug)]
283 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
284 /// nonsensical suggestions.
285 has_generic_args: bool,
286 /// Signals whether this `PathSegment` has lifetime arguments.
287 has_lifetime_args: bool,
292 fn from_path(path: &Path) -> Vec<Segment> {
293 path.segments.iter().map(|s| s.into()).collect()
296 fn from_ident(ident: Ident) -> Segment {
300 has_generic_args: false,
301 has_lifetime_args: false,
306 fn from_ident_and_id(ident: Ident, id: NodeId) -> Segment {
310 has_generic_args: false,
311 has_lifetime_args: false,
316 fn names_to_string(segments: &[Segment]) -> String {
317 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
321 impl<'a> From<&'a ast::PathSegment> for Segment {
322 fn from(seg: &'a ast::PathSegment) -> Segment {
323 let has_generic_args = seg.args.is_some();
324 let (args_span, has_lifetime_args) = if let Some(args) = seg.args.as_deref() {
326 GenericArgs::AngleBracketed(args) => {
327 let found_lifetimes = args
330 .any(|arg| matches!(arg, AngleBracketedArg::Arg(GenericArg::Lifetime(_))));
331 (args.span, found_lifetimes)
333 GenericArgs::Parenthesized(args) => (args.span, true),
348 /// An intermediate resolution result.
350 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
351 /// items are visible in their whole block, while `Res`es only from the place they are defined
354 enum LexicalScopeBinding<'a> {
355 Item(&'a NameBinding<'a>),
359 impl<'a> LexicalScopeBinding<'a> {
360 fn res(self) -> Res {
362 LexicalScopeBinding::Item(binding) => binding.res(),
363 LexicalScopeBinding::Res(res) => res,
368 #[derive(Copy, Clone, Debug)]
369 enum ModuleOrUniformRoot<'a> {
373 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
374 CrateRootAndExternPrelude,
376 /// Virtual module that denotes resolution in extern prelude.
377 /// Used for paths starting with `::` on 2018 edition.
380 /// Virtual module that denotes resolution in current scope.
381 /// Used only for resolving single-segment imports. The reason it exists is that import paths
382 /// are always split into two parts, the first of which should be some kind of module.
386 impl ModuleOrUniformRoot<'_> {
387 fn same_def(lhs: Self, rhs: Self) -> bool {
389 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
393 ModuleOrUniformRoot::CrateRootAndExternPrelude,
394 ModuleOrUniformRoot::CrateRootAndExternPrelude,
396 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
397 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
403 #[derive(Clone, Debug)]
404 enum PathResult<'a> {
405 Module(ModuleOrUniformRoot<'a>),
406 NonModule(PartialRes),
411 suggestion: Option<Suggestion>,
412 is_error_from_last_segment: bool,
416 impl<'a> PathResult<'a> {
419 is_error_from_last_segment: bool,
421 label_and_suggestion: impl FnOnce() -> (String, Option<Suggestion>),
422 ) -> PathResult<'a> {
423 let (label, suggestion) =
424 if finalize { label_and_suggestion() } else { (String::new(), None) };
425 PathResult::Failed { span, label, suggestion, is_error_from_last_segment }
431 /// An anonymous module; e.g., just a block.
436 /// { // This is an anonymous module
437 /// f(); // This resolves to (2) as we are inside the block.
440 /// f(); // Resolves to (1)
444 /// Any module with a name.
448 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
449 /// or the crate root (which is conceptually a top-level module).
450 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
451 /// * A trait or an enum (it implicitly contains associated types, methods and variant
453 Def(DefKind, DefId, Symbol),
457 /// Get name of the module.
458 pub fn name(&self) -> Option<Symbol> {
460 ModuleKind::Block(..) => None,
461 ModuleKind::Def(.., name) => Some(*name),
466 /// A key that identifies a binding in a given `Module`.
468 /// Multiple bindings in the same module can have the same key (in a valid
469 /// program) if all but one of them come from glob imports.
470 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
472 /// The identifier for the binding, always the `normalize_to_macros_2_0` version of the
476 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
477 /// `_` in the expanded AST that introduced this binding.
481 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
483 /// One node in the tree of modules.
485 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
488 /// * crate root (aka, top-level anonymous module)
491 /// * curly-braced block with statements
493 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
494 pub struct ModuleData<'a> {
495 /// The direct parent module (it may not be a `mod`, however).
496 parent: Option<Module<'a>>,
497 /// What kind of module this is, because this may not be a `mod`.
500 /// Mapping between names and their (possibly in-progress) resolutions in this module.
501 /// Resolutions in modules from other crates are not populated until accessed.
502 lazy_resolutions: Resolutions<'a>,
503 /// True if this is a module from other crate that needs to be populated on access.
504 populate_on_access: Cell<bool>,
506 /// Macro invocations that can expand into items in this module.
507 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
509 /// Whether `#[no_implicit_prelude]` is active.
510 no_implicit_prelude: bool,
512 glob_importers: RefCell<Vec<&'a Import<'a>>>,
513 globs: RefCell<Vec<&'a Import<'a>>>,
515 /// Used to memoize the traits in this module for faster searches through all traits in scope.
516 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
518 /// Span of the module itself. Used for error reporting.
524 type Module<'a> = &'a ModuleData<'a>;
526 impl<'a> ModuleData<'a> {
528 parent: Option<Module<'a>>,
532 no_implicit_prelude: bool,
534 let is_foreign = match kind {
535 ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
536 ModuleKind::Block(_) => false,
541 lazy_resolutions: Default::default(),
542 populate_on_access: Cell::new(is_foreign),
543 unexpanded_invocations: Default::default(),
545 glob_importers: RefCell::new(Vec::new()),
546 globs: RefCell::new(Vec::new()),
547 traits: RefCell::new(None),
553 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
555 R: AsMut<Resolver<'a>>,
556 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
558 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
559 if let Some(binding) = name_resolution.borrow().binding {
560 f(resolver, key.ident, key.ns, binding);
565 /// This modifies `self` in place. The traits will be stored in `self.traits`.
566 fn ensure_traits<R>(&'a self, resolver: &mut R)
568 R: AsMut<Resolver<'a>>,
570 let mut traits = self.traits.borrow_mut();
571 if traits.is_none() {
572 let mut collected_traits = Vec::new();
573 self.for_each_child(resolver, |_, name, ns, binding| {
577 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
578 collected_traits.push((name, binding))
581 *traits = Some(collected_traits.into_boxed_slice());
585 fn res(&self) -> Option<Res> {
587 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
592 // Public for rustdoc.
593 pub fn def_id(&self) -> DefId {
594 self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
597 fn opt_def_id(&self) -> Option<DefId> {
599 ModuleKind::Def(_, def_id, _) => Some(def_id),
604 // `self` resolves to the first module ancestor that `is_normal`.
605 fn is_normal(&self) -> bool {
606 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
609 fn is_trait(&self) -> bool {
610 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
613 fn nearest_item_scope(&'a self) -> Module<'a> {
615 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
616 self.parent.expect("enum or trait module without a parent")
622 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
623 /// This may be the crate root.
624 fn nearest_parent_mod(&self) -> DefId {
626 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
627 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
631 fn is_ancestor_of(&self, mut other: &Self) -> bool {
632 while !ptr::eq(self, other) {
633 if let Some(parent) = other.parent {
643 impl<'a> fmt::Debug for ModuleData<'a> {
644 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
645 write!(f, "{:?}", self.res())
649 /// Records a possibly-private value, type, or module definition.
650 #[derive(Clone, Debug)]
651 pub struct NameBinding<'a> {
652 kind: NameBindingKind<'a>,
653 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
654 expansion: LocalExpnId,
659 pub trait ToNameBinding<'a> {
660 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
663 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
664 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
669 #[derive(Clone, Debug)]
670 enum NameBindingKind<'a> {
671 Res(Res, /* is_macro_export */ bool),
673 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
676 impl<'a> NameBindingKind<'a> {
677 /// Is this a name binding of an import?
678 fn is_import(&self) -> bool {
679 matches!(*self, NameBindingKind::Import { .. })
683 struct PrivacyError<'a> {
685 binding: &'a NameBinding<'a>,
689 struct UseError<'a> {
690 err: DiagnosticBuilder<'a, ErrorGuaranteed>,
691 /// Candidates which user could `use` to access the missing type.
692 candidates: Vec<ImportSuggestion>,
693 /// The `DefId` of the module to place the use-statements in.
695 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
697 /// Extra free-form suggestion.
698 suggestion: Option<(Span, &'static str, String, Applicability)>,
701 #[derive(Clone, Copy, PartialEq, Debug)]
706 MacroRulesVsModularized,
714 fn descr(self) -> &'static str {
716 AmbiguityKind::Import => "multiple potential import sources",
717 AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute",
718 AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute",
719 AmbiguityKind::MacroRulesVsModularized => {
720 "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module"
722 AmbiguityKind::GlobVsOuter => {
723 "a conflict between a name from a glob import and an outer scope during import or macro resolution"
725 AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module",
726 AmbiguityKind::GlobVsExpanded => {
727 "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution"
729 AmbiguityKind::MoreExpandedVsOuter => {
730 "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution"
736 /// Miscellaneous bits of metadata for better ambiguity error reporting.
737 #[derive(Clone, Copy, PartialEq)]
738 enum AmbiguityErrorMisc {
745 struct AmbiguityError<'a> {
748 b1: &'a NameBinding<'a>,
749 b2: &'a NameBinding<'a>,
750 misc1: AmbiguityErrorMisc,
751 misc2: AmbiguityErrorMisc,
754 impl<'a> NameBinding<'a> {
755 fn module(&self) -> Option<Module<'a>> {
757 NameBindingKind::Module(module) => Some(module),
758 NameBindingKind::Import { binding, .. } => binding.module(),
763 fn res(&self) -> Res {
765 NameBindingKind::Res(res, _) => res,
766 NameBindingKind::Module(module) => module.res().unwrap(),
767 NameBindingKind::Import { binding, .. } => binding.res(),
771 fn is_ambiguity(&self) -> bool {
772 self.ambiguity.is_some()
774 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
779 fn is_possibly_imported_variant(&self) -> bool {
781 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
782 NameBindingKind::Res(
783 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
786 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
790 fn is_extern_crate(&self) -> bool {
792 NameBindingKind::Import {
793 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
796 NameBindingKind::Module(&ModuleData {
797 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
799 }) => def_id.is_crate_root(),
804 fn is_import(&self) -> bool {
805 matches!(self.kind, NameBindingKind::Import { .. })
808 fn is_glob_import(&self) -> bool {
810 NameBindingKind::Import { import, .. } => import.is_glob(),
815 fn is_importable(&self) -> bool {
818 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
822 fn macro_kind(&self) -> Option<MacroKind> {
823 self.res().macro_kind()
826 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
827 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
828 // Then this function returns `true` if `self` may emerge from a macro *after* that
829 // in some later round and screw up our previously found resolution.
830 // See more detailed explanation in
831 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
834 invoc_parent_expansion: LocalExpnId,
835 binding: &NameBinding<'_>,
837 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
838 // Expansions are partially ordered, so "may appear after" is an inversion of
839 // "certainly appears before or simultaneously" and includes unordered cases.
840 let self_parent_expansion = self.expansion;
841 let other_parent_expansion = binding.expansion;
842 let certainly_before_other_or_simultaneously =
843 other_parent_expansion.is_descendant_of(self_parent_expansion);
844 let certainly_before_invoc_or_simultaneously =
845 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
846 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
850 #[derive(Debug, Default, Clone)]
851 pub struct ExternPreludeEntry<'a> {
852 extern_crate_item: Option<&'a NameBinding<'a>>,
853 pub introduced_by_item: bool,
856 /// Used for better errors for E0773
857 enum BuiltinMacroState {
858 NotYetSeen(SyntaxExtensionKind),
863 resolutions: DeriveResolutions,
864 helper_attrs: Vec<(usize, Ident)>,
865 has_derive_copy: bool,
868 /// The main resolver class.
870 /// This is the visitor that walks the whole crate.
871 pub struct Resolver<'a> {
872 session: &'a Session,
874 definitions: Definitions,
876 graph_root: Module<'a>,
878 prelude: Option<Module<'a>>,
879 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
881 /// N.B., this is used only for better diagnostics, not name resolution itself.
882 has_self: FxHashSet<DefId>,
884 /// Names of fields of an item `DefId` accessible with dot syntax.
885 /// Used for hints during error reporting.
886 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
888 /// All imports known to succeed or fail.
889 determined_imports: Vec<&'a Import<'a>>,
891 /// All non-determined imports.
892 indeterminate_imports: Vec<&'a Import<'a>>,
894 // Spans for local variables found during pattern resolution.
895 // Used for suggestions during error reporting.
896 pat_span_map: NodeMap<Span>,
898 /// Resolutions for nodes that have a single resolution.
899 partial_res_map: NodeMap<PartialRes>,
900 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
901 import_res_map: NodeMap<PerNS<Option<Res>>>,
902 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
903 label_res_map: NodeMap<NodeId>,
904 /// Resolutions for lifetimes.
905 lifetimes_res_map: NodeMap<LifetimeRes>,
906 /// Lifetime parameters that lowering will have to introduce.
907 extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,
909 /// `CrateNum` resolutions of `extern crate` items.
910 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
911 reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
912 trait_map: NodeMap<Vec<TraitCandidate>>,
914 /// A map from nodes to anonymous modules.
915 /// Anonymous modules are pseudo-modules that are implicitly created around items
916 /// contained within blocks.
918 /// For example, if we have this:
926 /// There will be an anonymous module created around `g` with the ID of the
927 /// entry block for `f`.
928 block_map: NodeMap<Module<'a>>,
929 /// A fake module that contains no definition and no prelude. Used so that
930 /// some AST passes can generate identifiers that only resolve to local or
932 empty_module: Module<'a>,
933 module_map: FxHashMap<DefId, Module<'a>>,
934 binding_parent_modules: FxHashMap<Interned<'a, NameBinding<'a>>, Module<'a>>,
935 underscore_disambiguator: u32,
937 /// Maps glob imports to the names of items actually imported.
938 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
939 /// Visibilities in "lowered" form, for all entities that have them.
940 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
941 has_pub_restricted: bool,
942 used_imports: FxHashSet<NodeId>,
943 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
944 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
946 /// Privacy errors are delayed until the end in order to deduplicate them.
947 privacy_errors: Vec<PrivacyError<'a>>,
948 /// Ambiguity errors are delayed for deduplication.
949 ambiguity_errors: Vec<AmbiguityError<'a>>,
950 /// `use` injections are delayed for better placement and deduplication.
951 use_injections: Vec<UseError<'a>>,
952 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
953 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
955 arenas: &'a ResolverArenas<'a>,
956 dummy_binding: &'a NameBinding<'a>,
958 crate_loader: CrateLoader<'a>,
959 macro_names: FxHashSet<Ident>,
960 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
961 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
962 /// the surface (`macro` items in libcore), but are actually attributes or derives.
963 builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
964 registered_attrs: FxHashSet<Ident>,
965 registered_tools: RegisteredTools,
966 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
967 /// FIXME: The only user of this is a doc link resolution hack for rustdoc.
968 all_macro_rules: FxHashMap<Symbol, Res>,
969 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
970 dummy_ext_bang: Lrc<SyntaxExtension>,
971 dummy_ext_derive: Lrc<SyntaxExtension>,
972 non_macro_attr: Lrc<SyntaxExtension>,
973 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
974 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
975 unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
976 proc_macro_stubs: FxHashSet<LocalDefId>,
977 /// Traces collected during macro resolution and validated when it's complete.
978 single_segment_macro_resolutions:
979 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
980 multi_segment_macro_resolutions:
981 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
982 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
983 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
984 /// Derive macros cannot modify the item themselves and have to store the markers in the global
985 /// context, so they attach the markers to derive container IDs using this resolver table.
986 containers_deriving_copy: FxHashSet<LocalExpnId>,
987 /// Parent scopes in which the macros were invoked.
988 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
989 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
990 /// `macro_rules` scopes *produced* by expanding the macro invocations,
991 /// include all the `macro_rules` items and other invocations generated by them.
992 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
993 /// Helper attributes that are in scope for the given expansion.
994 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
995 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
996 /// with the given `ExpnId`.
997 derive_data: FxHashMap<LocalExpnId, DeriveData>,
999 /// Avoid duplicated errors for "name already defined".
1000 name_already_seen: FxHashMap<Symbol, Span>,
1002 potentially_unused_imports: Vec<&'a Import<'a>>,
1004 /// Table for mapping struct IDs into struct constructor IDs,
1005 /// it's not used during normal resolution, only for better error reporting.
1006 /// Also includes of list of each fields visibility
1007 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1009 /// Features enabled for this crate.
1010 active_features: FxHashSet<Symbol>,
1012 lint_buffer: LintBuffer,
1014 next_node_id: NodeId,
1016 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1017 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1019 /// Indices of unnamed struct or variant fields with unresolved attributes.
1020 placeholder_field_indices: FxHashMap<NodeId, usize>,
1021 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1022 /// we know what parent node that fragment should be attached to thanks to this table,
1023 /// and how the `impl Trait` fragments were introduced.
1024 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1026 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1027 /// FIXME: Replace with a more general AST map (together with some other fields).
1028 trait_impl_items: FxHashSet<LocalDefId>,
1030 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1031 /// Amount of lifetime parameters for each item in the crate.
1032 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1034 main_def: Option<MainDefinition>,
1035 trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
1036 /// A list of proc macro LocalDefIds, written out in the order in which
1037 /// they are declared in the static array generated by proc_macro_harness.
1038 proc_macros: Vec<NodeId>,
1039 confused_type_with_std_module: FxHashMap<Span, Span>,
1041 access_levels: AccessLevels,
1044 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1046 pub struct ResolverArenas<'a> {
1047 modules: TypedArena<ModuleData<'a>>,
1048 local_modules: RefCell<Vec<Module<'a>>>,
1049 imports: TypedArena<Import<'a>>,
1050 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1051 ast_paths: TypedArena<ast::Path>,
1052 dropless: DroplessArena,
1055 impl<'a> ResolverArenas<'a> {
1058 parent: Option<Module<'a>>,
1062 no_implicit_prelude: bool,
1063 module_map: &mut FxHashMap<DefId, Module<'a>>,
1066 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1067 let def_id = module.opt_def_id();
1068 if def_id.map_or(true, |def_id| def_id.is_local()) {
1069 self.local_modules.borrow_mut().push(module);
1071 if let Some(def_id) = def_id {
1072 module_map.insert(def_id, module);
1076 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1077 self.local_modules.borrow()
1079 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1080 self.dropless.alloc(name_binding)
1082 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1083 self.imports.alloc(import)
1085 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1086 self.name_resolutions.alloc(Default::default())
1088 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1089 Interned::new_unchecked(self.dropless.alloc(Cell::new(scope)))
1091 fn alloc_macro_rules_binding(
1093 binding: MacroRulesBinding<'a>,
1094 ) -> &'a MacroRulesBinding<'a> {
1095 self.dropless.alloc(binding)
1097 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1098 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1100 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1101 self.dropless.alloc_from_iter(spans)
1105 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1106 fn as_mut(&mut self) -> &mut Resolver<'a> {
1111 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1112 fn parent(self, id: DefId) -> Option<DefId> {
1113 match id.as_local() {
1114 Some(id) => self.definitions.def_key(id).parent,
1115 None => self.cstore().def_key(id).parent,
1117 .map(|index| DefId { index, ..id })
1121 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1122 /// the resolver is no longer needed as all the relevant information is inline.
1123 impl ResolverAstLowering for Resolver<'_> {
1124 fn def_key(&self, id: DefId) -> DefKey {
1125 if let Some(id) = id.as_local() {
1126 self.definitions.def_key(id)
1128 self.cstore().def_key(id)
1133 fn def_span(&self, id: LocalDefId) -> Span {
1134 self.definitions.def_span(id)
1137 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1138 if let Some(def_id) = def_id.as_local() {
1139 self.item_generics_num_lifetimes[&def_id]
1141 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1145 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1146 self.legacy_const_generic_args(expr)
1149 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1150 self.partial_res_map.get(&id).cloned()
1153 fn get_import_res(&self, id: NodeId) -> PerNS<Option<Res>> {
1154 self.import_res_map.get(&id).cloned().unwrap_or_default()
1157 fn get_label_res(&self, id: NodeId) -> Option<NodeId> {
1158 self.label_res_map.get(&id).cloned()
1161 fn get_lifetime_res(&self, id: NodeId) -> Option<LifetimeRes> {
1162 self.lifetimes_res_map.get(&id).copied()
1165 fn take_extra_lifetime_params(&mut self, id: NodeId) -> Vec<(Ident, NodeId, LifetimeRes)> {
1166 self.extra_lifetime_params_map.remove(&id).unwrap_or_default()
1169 fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
1170 StableHashingContext::new(self.session, &self.definitions, self.crate_loader.cstore())
1173 fn definitions(&self) -> &Definitions {
1177 fn next_node_id(&mut self) -> NodeId {
1181 fn take_trait_map(&mut self, node: NodeId) -> Option<Vec<TraitCandidate>> {
1182 self.trait_map.remove(&node)
1185 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1186 self.node_id_to_def_id.get(&node).copied()
1189 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1190 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1193 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1194 match def_id.as_local() {
1195 Some(def_id) => self.definitions.def_path_hash(def_id),
1196 None => self.cstore().def_path_hash(def_id),
1200 /// Adds a definition with a parent definition.
1204 node_id: ast::NodeId,
1210 !self.node_id_to_def_id.contains_key(&node_id),
1211 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1214 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1217 let def_id = self.definitions.create_def(parent, data, expn_id, span);
1219 // Some things for which we allocate `LocalDefId`s don't correspond to
1220 // anything in the AST, so they don't have a `NodeId`. For these cases
1221 // we don't need a mapping from `NodeId` to `LocalDefId`.
1222 if node_id != ast::DUMMY_NODE_ID {
1223 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1224 self.node_id_to_def_id.insert(node_id, def_id);
1226 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1231 fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind {
1232 self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang)
1236 impl<'a> Resolver<'a> {
1238 session: &'a Session,
1241 metadata_loader: Box<MetadataLoaderDyn>,
1242 arenas: &'a ResolverArenas<'a>,
1244 let root_def_id = CRATE_DEF_ID.to_def_id();
1245 let mut module_map = FxHashMap::default();
1246 let graph_root = arenas.new_module(
1248 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1250 krate.spans.inner_span,
1251 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1254 let empty_module = arenas.new_module(
1256 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1260 &mut FxHashMap::default(),
1263 let definitions = Definitions::new(session.local_stable_crate_id(), krate.spans.inner_span);
1265 let mut visibilities = FxHashMap::default();
1266 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1268 let mut def_id_to_node_id = IndexVec::default();
1269 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), CRATE_DEF_ID);
1270 let mut node_id_to_def_id = FxHashMap::default();
1271 node_id_to_def_id.insert(CRATE_NODE_ID, CRATE_DEF_ID);
1273 let mut invocation_parents = FxHashMap::default();
1274 invocation_parents.insert(LocalExpnId::ROOT, (CRATE_DEF_ID, ImplTraitContext::Existential));
1276 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1280 .filter(|(_, entry)| entry.add_prelude)
1281 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1284 if !session.contains_name(&krate.attrs, sym::no_core) {
1285 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1286 if !session.contains_name(&krate.attrs, sym::no_std) {
1287 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1291 let (registered_attrs, registered_tools) =
1292 macros::registered_attrs_and_tools(session, &krate.attrs);
1294 let features = session.features_untracked();
1296 let mut resolver = Resolver {
1301 // The outermost module has def ID 0; this is not reflected in the
1307 has_self: FxHashSet::default(),
1308 field_names: FxHashMap::default(),
1310 determined_imports: Vec::new(),
1311 indeterminate_imports: Vec::new(),
1313 pat_span_map: Default::default(),
1314 partial_res_map: Default::default(),
1315 import_res_map: Default::default(),
1316 label_res_map: Default::default(),
1317 lifetimes_res_map: Default::default(),
1318 extra_lifetime_params_map: Default::default(),
1319 extern_crate_map: Default::default(),
1320 reexport_map: FxHashMap::default(),
1321 trait_map: NodeMap::default(),
1322 underscore_disambiguator: 0,
1325 block_map: Default::default(),
1326 binding_parent_modules: FxHashMap::default(),
1327 ast_transform_scopes: FxHashMap::default(),
1329 glob_map: Default::default(),
1331 has_pub_restricted: false,
1332 used_imports: FxHashSet::default(),
1333 maybe_unused_trait_imports: Default::default(),
1334 maybe_unused_extern_crates: Vec::new(),
1336 privacy_errors: Vec::new(),
1337 ambiguity_errors: Vec::new(),
1338 use_injections: Vec::new(),
1339 macro_expanded_macro_export_errors: BTreeSet::new(),
1342 dummy_binding: arenas.alloc_name_binding(NameBinding {
1343 kind: NameBindingKind::Res(Res::Err, false),
1345 expansion: LocalExpnId::ROOT,
1347 vis: ty::Visibility::Public,
1350 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1351 macro_names: FxHashSet::default(),
1352 builtin_macros: Default::default(),
1353 builtin_macro_kinds: Default::default(),
1356 macro_use_prelude: FxHashMap::default(),
1357 all_macro_rules: Default::default(),
1358 macro_map: FxHashMap::default(),
1359 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1360 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1361 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1362 invocation_parent_scopes: Default::default(),
1363 output_macro_rules_scopes: Default::default(),
1364 helper_attrs: Default::default(),
1365 derive_data: Default::default(),
1366 local_macro_def_scopes: FxHashMap::default(),
1367 name_already_seen: FxHashMap::default(),
1368 potentially_unused_imports: Vec::new(),
1369 struct_constructors: Default::default(),
1370 unused_macros: Default::default(),
1371 proc_macro_stubs: Default::default(),
1372 single_segment_macro_resolutions: Default::default(),
1373 multi_segment_macro_resolutions: Default::default(),
1374 builtin_attrs: Default::default(),
1375 containers_deriving_copy: Default::default(),
1376 active_features: features
1377 .declared_lib_features
1379 .map(|(feat, ..)| *feat)
1380 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1382 lint_buffer: LintBuffer::default(),
1383 next_node_id: CRATE_NODE_ID,
1386 placeholder_field_indices: Default::default(),
1388 trait_impl_items: Default::default(),
1389 legacy_const_generic_args: Default::default(),
1390 item_generics_num_lifetimes: Default::default(),
1391 main_def: Default::default(),
1392 trait_impls: Default::default(),
1393 proc_macros: Default::default(),
1394 confused_type_with_std_module: Default::default(),
1395 access_levels: Default::default(),
1398 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1399 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1406 parent: Option<Module<'a>>,
1410 no_implicit_prelude: bool,
1412 let module_map = &mut self.module_map;
1413 self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
1416 pub fn next_node_id(&mut self) -> NodeId {
1417 let start = self.next_node_id;
1418 let next = start.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
1419 self.next_node_id = ast::NodeId::from_u32(next);
1423 pub fn next_node_ids(&mut self, count: usize) -> std::ops::Range<NodeId> {
1424 let start = self.next_node_id;
1425 let end = start.as_usize().checked_add(count).expect("input too large; ran out of NodeIds");
1426 self.next_node_id = ast::NodeId::from_usize(end);
1427 start..self.next_node_id
1430 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1431 &mut self.lint_buffer
1434 pub fn arenas() -> ResolverArenas<'a> {
1438 pub fn into_outputs(self) -> ResolverOutputs {
1439 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1440 let definitions = self.definitions;
1441 let visibilities = self.visibilities;
1442 let has_pub_restricted = self.has_pub_restricted;
1443 let extern_crate_map = self.extern_crate_map;
1444 let reexport_map = self.reexport_map;
1445 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1446 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1447 let glob_map = self.glob_map;
1448 let main_def = self.main_def;
1449 let confused_type_with_std_module = self.confused_type_with_std_module;
1450 let access_levels = self.access_levels;
1453 cstore: Box::new(self.crate_loader.into_cstore()),
1460 maybe_unused_trait_imports,
1461 maybe_unused_extern_crates,
1462 extern_prelude: self
1465 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1468 trait_impls: self.trait_impls,
1470 confused_type_with_std_module,
1471 registered_tools: self.registered_tools,
1475 pub fn clone_outputs(&self) -> ResolverOutputs {
1476 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1478 definitions: self.definitions.clone(),
1479 access_levels: self.access_levels.clone(),
1480 cstore: Box::new(self.cstore().clone()),
1481 visibilities: self.visibilities.clone(),
1482 has_pub_restricted: self.has_pub_restricted,
1483 extern_crate_map: self.extern_crate_map.clone(),
1484 reexport_map: self.reexport_map.clone(),
1485 glob_map: self.glob_map.clone(),
1486 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1487 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1488 extern_prelude: self
1491 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1493 main_def: self.main_def,
1494 trait_impls: self.trait_impls.clone(),
1496 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1497 registered_tools: self.registered_tools.clone(),
1501 pub fn cstore(&self) -> &CStore {
1502 self.crate_loader.cstore()
1505 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1507 MacroKind::Bang => self.dummy_ext_bang.clone(),
1508 MacroKind::Derive => self.dummy_ext_derive.clone(),
1509 MacroKind::Attr => self.non_macro_attr.clone(),
1513 /// Runs the function on each namespace.
1514 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1520 fn is_builtin_macro(&mut self, res: Res) -> bool {
1521 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1524 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1526 match ctxt.outer_expn_data().macro_def_id {
1527 Some(def_id) => return def_id,
1528 None => ctxt.remove_mark(),
1533 /// Entry point to crate resolution.
1534 pub fn resolve_crate(&mut self, krate: &Crate) {
1535 self.session.time("resolve_crate", || {
1536 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1537 self.session.time("resolve_access_levels", || {
1538 AccessLevelsVisitor::compute_access_levels(self, krate)
1540 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1541 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1542 self.session.time("resolve_main", || self.resolve_main());
1543 self.session.time("resolve_check_unused", || self.check_unused(krate));
1544 self.session.time("resolve_report_errors", || self.report_errors(krate));
1545 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1549 pub fn traits_in_scope(
1551 current_trait: Option<Module<'a>>,
1552 parent_scope: &ParentScope<'a>,
1553 ctxt: SyntaxContext,
1554 assoc_item: Option<(Symbol, Namespace)>,
1555 ) -> Vec<TraitCandidate> {
1556 let mut found_traits = Vec::new();
1558 if let Some(module) = current_trait {
1559 if self.trait_may_have_item(Some(module), assoc_item) {
1560 let def_id = module.def_id();
1561 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1565 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1567 Scope::Module(module, _) => {
1568 this.traits_in_module(module, assoc_item, &mut found_traits);
1570 Scope::StdLibPrelude => {
1571 if let Some(module) = this.prelude {
1572 this.traits_in_module(module, assoc_item, &mut found_traits);
1575 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1576 _ => unreachable!(),
1584 fn traits_in_module(
1587 assoc_item: Option<(Symbol, Namespace)>,
1588 found_traits: &mut Vec<TraitCandidate>,
1590 module.ensure_traits(self);
1591 let traits = module.traits.borrow();
1592 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1593 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1594 let def_id = trait_binding.res().def_id();
1595 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1596 found_traits.push(TraitCandidate { def_id, import_ids });
1601 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1602 // associated item with the given name and namespace (if specified). This is a conservative
1603 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1604 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1605 // associated items.
1606 fn trait_may_have_item(
1608 trait_module: Option<Module<'a>>,
1609 assoc_item: Option<(Symbol, Namespace)>,
1611 match (trait_module, assoc_item) {
1612 (Some(trait_module), Some((name, ns))) => {
1613 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1614 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1615 assoc_ns == ns && assoc_ident.name == name
1622 fn find_transitive_imports(
1624 mut kind: &NameBindingKind<'_>,
1626 ) -> SmallVec<[LocalDefId; 1]> {
1627 let mut import_ids = smallvec![];
1628 while let NameBindingKind::Import { import, binding, .. } = kind {
1629 let id = self.local_def_id(import.id);
1630 self.maybe_unused_trait_imports.insert(id);
1631 self.add_to_glob_map(&import, trait_name);
1632 import_ids.push(id);
1633 kind = &binding.kind;
1638 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1639 let ident = ident.normalize_to_macros_2_0();
1640 let disambiguator = if ident.name == kw::Underscore {
1641 self.underscore_disambiguator += 1;
1642 self.underscore_disambiguator
1646 BindingKey { ident, ns, disambiguator }
1649 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1650 if module.populate_on_access.get() {
1651 module.populate_on_access.set(false);
1652 self.build_reduced_graph_external(module);
1654 &module.lazy_resolutions
1661 ) -> &'a RefCell<NameResolution<'a>> {
1663 .resolutions(module)
1666 .or_insert_with(|| self.arenas.alloc_name_resolution())
1672 used_binding: &'a NameBinding<'a>,
1673 is_lexical_scope: bool,
1675 if let Some((b2, kind)) = used_binding.ambiguity {
1676 self.ambiguity_errors.push(AmbiguityError {
1681 misc1: AmbiguityErrorMisc::None,
1682 misc2: AmbiguityErrorMisc::None,
1685 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1686 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1687 // but not introduce it, as used if they are accessed from lexical scope.
1688 if is_lexical_scope {
1689 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1690 if let Some(crate_item) = entry.extern_crate_item {
1691 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1698 import.used.set(true);
1699 self.used_imports.insert(import.id);
1700 self.add_to_glob_map(&import, ident);
1701 self.record_use(ident, binding, false);
1706 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1707 if import.is_glob() {
1708 let def_id = self.local_def_id(import.id);
1709 self.glob_map.entry(def_id).or_default().insert(ident.name);
1713 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1714 debug!("resolve_crate_root({:?})", ident);
1715 let mut ctxt = ident.span.ctxt();
1716 let mark = if ident.name == kw::DollarCrate {
1717 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1718 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1719 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
1720 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
1721 // definitions actually produced by `macro` and `macro` definitions produced by
1722 // `macro_rules!`, but at least such configurations are not stable yet.
1723 ctxt = ctxt.normalize_to_macro_rules();
1725 "resolve_crate_root: marks={:?}",
1726 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
1728 let mut iter = ctxt.marks().into_iter().rev().peekable();
1729 let mut result = None;
1730 // Find the last opaque mark from the end if it exists.
1731 while let Some(&(mark, transparency)) = iter.peek() {
1732 if transparency == Transparency::Opaque {
1733 result = Some(mark);
1740 "resolve_crate_root: found opaque mark {:?} {:?}",
1742 result.map(|r| r.expn_data())
1744 // Then find the last semi-transparent mark from the end if it exists.
1745 for (mark, transparency) in iter {
1746 if transparency == Transparency::SemiTransparent {
1747 result = Some(mark);
1753 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
1755 result.map(|r| r.expn_data())
1759 debug!("resolve_crate_root: not DollarCrate");
1760 ctxt = ctxt.normalize_to_macros_2_0();
1761 ctxt.adjust(ExpnId::root())
1763 let module = match mark {
1764 Some(def) => self.expn_def_scope(def),
1767 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
1770 return self.graph_root;
1773 let module = self.expect_module(
1774 module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(),
1777 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
1786 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1787 let mut module = self.expect_module(module.nearest_parent_mod());
1788 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
1789 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
1790 module = self.expect_module(parent.nearest_parent_mod());
1795 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
1796 debug!("(recording res) recording {:?} for {}", resolution, node_id);
1797 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
1798 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
1802 fn record_pat_span(&mut self, node: NodeId, span: Span) {
1803 debug!("(recording pat) recording {:?} for {:?}", node, span);
1804 self.pat_span_map.insert(node, span);
1807 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
1808 vis.is_accessible_from(module.nearest_parent_mod(), self)
1811 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
1812 if let Some(old_module) =
1813 self.binding_parent_modules.insert(Interned::new_unchecked(binding), module)
1815 if !ptr::eq(module, old_module) {
1816 span_bug!(binding.span, "parent module is reset for binding");
1821 fn disambiguate_macro_rules_vs_modularized(
1823 macro_rules: &'a NameBinding<'a>,
1824 modularized: &'a NameBinding<'a>,
1826 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
1827 // is disambiguated to mitigate regressions from macro modularization.
1828 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
1830 self.binding_parent_modules.get(&Interned::new_unchecked(macro_rules)),
1831 self.binding_parent_modules.get(&Interned::new_unchecked(modularized)),
1833 (Some(macro_rules), Some(modularized)) => {
1834 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
1835 && modularized.is_ancestor_of(macro_rules)
1841 fn extern_prelude_get(&mut self, ident: Ident, finalize: bool) -> Option<&'a NameBinding<'a>> {
1842 if ident.is_path_segment_keyword() {
1843 // Make sure `self`, `super` etc produce an error when passed to here.
1846 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
1847 if let Some(binding) = entry.extern_crate_item {
1848 if finalize && entry.introduced_by_item {
1849 self.record_use(ident, binding, false);
1853 let crate_id = if finalize {
1854 let Some(crate_id) =
1855 self.crate_loader.process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
1858 self.crate_loader.maybe_process_path_extern(ident.name)?
1860 let crate_root = self.expect_module(crate_id.as_def_id());
1862 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
1863 .to_name_binding(self.arenas),
1869 /// Rustdoc uses this to resolve doc link paths in a recoverable way. `PathResult<'a>`
1870 /// isn't something that can be returned because it can't be made to live that long,
1871 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1872 /// just that an error occurred.
1873 pub fn resolve_rustdoc_path(
1877 mut module_id: DefId,
1880 Vec::from_iter(path_str.split("::").map(Ident::from_str).map(Segment::from_ident));
1881 if let Some(segment) = segments.first_mut() {
1882 if segment.ident.name == kw::Crate {
1883 // FIXME: `resolve_path` always resolves `crate` to the current crate root, but
1884 // rustdoc wants it to resolve to the `module_id`'s crate root. This trick of
1885 // replacing `crate` with `self` and changing the current module should achieve
1887 segment.ident.name = kw::SelfLower;
1888 module_id = module_id.krate.as_def_id();
1889 } else if segment.ident.name == kw::Empty {
1890 segment.ident.name = kw::PathRoot;
1894 let module = self.expect_module(module_id);
1895 match self.maybe_resolve_path(&segments, Some(ns), &ParentScope::module(module, self)) {
1896 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Some(module.res().unwrap()),
1897 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
1898 Some(path_res.base_res())
1900 PathResult::Module(ModuleOrUniformRoot::ExternPrelude)
1901 | PathResult::NonModule(..)
1902 | PathResult::Failed { .. } => None,
1903 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
1908 pub fn graph_root(&self) -> Module<'a> {
1913 pub fn take_all_macro_rules(&mut self) -> FxHashMap<Symbol, Res> {
1914 mem::take(&mut self.all_macro_rules)
1918 /// For local modules returns only reexports, for external modules returns all children.
1919 pub fn module_children_or_reexports(&self, def_id: DefId) -> Vec<ModChild> {
1920 if let Some(def_id) = def_id.as_local() {
1921 self.reexport_map.get(&def_id).cloned().unwrap_or_default()
1923 self.cstore().module_children_untracked(def_id, self.session)
1927 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
1929 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
1930 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
1933 /// Checks if an expression refers to a function marked with
1934 /// `#[rustc_legacy_const_generics]` and returns the argument index list
1935 /// from the attribute.
1936 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1937 if let ExprKind::Path(None, path) = &expr.kind {
1938 // Don't perform legacy const generics rewriting if the path already
1939 // has generic arguments.
1940 if path.segments.last().unwrap().args.is_some() {
1944 let partial_res = self.partial_res_map.get(&expr.id)?;
1945 if partial_res.unresolved_segments() != 0 {
1949 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
1950 // We only support cross-crate argument rewriting. Uses
1951 // within the same crate should be updated to use the new
1952 // const generics style.
1953 if def_id.is_local() {
1957 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
1963 .item_attrs_untracked(def_id, self.session)
1964 .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
1965 let mut ret = Vec::new();
1966 for meta in attr.meta_item_list()? {
1967 match meta.literal()?.kind {
1968 LitKind::Int(a, _) => ret.push(a as usize),
1969 _ => panic!("invalid arg index"),
1972 // Cache the lookup to avoid parsing attributes for an iterm multiple times.
1973 self.legacy_const_generic_args.insert(def_id, Some(ret.clone()));
1980 fn resolve_main(&mut self) {
1981 let module = self.graph_root;
1982 let ident = Ident::with_dummy_span(sym::main);
1983 let parent_scope = &ParentScope::module(module, self);
1985 let Ok(name_binding) = self.maybe_resolve_ident_in_module(
1986 ModuleOrUniformRoot::Module(module),
1994 let res = name_binding.res();
1995 let is_import = name_binding.is_import();
1996 let span = name_binding.span;
1997 if let Res::Def(DefKind::Fn, _) = res {
1998 self.record_use(ident, name_binding, false);
2000 self.main_def = Some(MainDefinition { res, is_import, span });
2004 fn names_to_string(names: &[Symbol]) -> String {
2005 let mut result = String::new();
2006 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
2008 result.push_str("::");
2010 if Ident::with_dummy_span(*name).is_raw_guess() {
2011 result.push_str("r#");
2013 result.push_str(name.as_str());
2018 fn path_names_to_string(path: &Path) -> String {
2019 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
2022 /// A somewhat inefficient routine to obtain the name of a module.
2023 fn module_to_string(module: Module<'_>) -> Option<String> {
2024 let mut names = Vec::new();
2026 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
2027 if let ModuleKind::Def(.., name) = module.kind {
2028 if let Some(parent) = module.parent {
2030 collect_mod(names, parent);
2033 names.push(Symbol::intern("<opaque>"));
2034 collect_mod(names, module.parent.unwrap());
2037 collect_mod(&mut names, module);
2039 if names.is_empty() {
2043 Some(names_to_string(&names))
2046 #[derive(Copy, Clone, Debug)]
2048 /// Do not issue the lint.
2051 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
2052 /// In this case, we can take the span of that path.
2053 SimplePath(NodeId, Span),
2055 /// This lint comes from a `use` statement. In this case, what we
2056 /// care about really is the *root* `use` statement; e.g., if we
2057 /// have nested things like `use a::{b, c}`, we care about the
2059 UsePath { root_id: NodeId, root_span: Span, path_span: Span },
2061 /// This is the "trait item" from a fully qualified path. For example,
2062 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
2063 /// The `path_span` is the span of the to the trait itself (`X::Y`).
2064 QPathTrait { qpath_id: NodeId, qpath_span: Span, path_span: Span },
2068 fn node_id_and_path_span(&self) -> Option<(NodeId, Span)> {
2070 Finalize::No => None,
2071 Finalize::SimplePath(id, path_span)
2072 | Finalize::UsePath { root_id: id, path_span, .. }
2073 | Finalize::QPathTrait { qpath_id: id, path_span, .. } => Some((id, path_span)),
2077 fn node_id(&self) -> Option<NodeId> {
2078 self.node_id_and_path_span().map(|(id, _)| id)
2081 fn path_span(&self) -> Option<Span> {
2082 self.node_id_and_path_span().map(|(_, path_span)| path_span)
2086 pub fn provide(providers: &mut Providers) {
2087 late::lifetimes::provide(providers);