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 `rustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
12 #![feature(box_patterns)]
13 #![feature(drain_filter)]
14 #![feature(bool_to_option)]
15 #![feature(crate_visibility_modifier)]
16 #![feature(let_chains)]
18 #![feature(never_type)]
20 #![recursion_limit = "256"]
21 #![allow(rustdoc::private_intra_doc_links)]
22 #![allow(rustc::potential_query_instability)]
27 pub use rustc_hir::def::{Namespace, PerNS};
31 use rustc_arena::{DroplessArena, TypedArena};
32 use rustc_ast::node_id::NodeMap;
33 use rustc_ast::ptr::P;
34 use rustc_ast::visit::{self, Visitor};
35 use rustc_ast::{self as ast, NodeId};
36 use rustc_ast::{Crate, CRATE_NODE_ID};
37 use rustc_ast::{Expr, ExprKind, LitKind};
38 use rustc_ast::{ItemKind, ModKind, Path};
39 use rustc_ast_lowering::ResolverAstLowering;
40 use rustc_ast_pretty::pprust;
41 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
42 use rustc_data_structures::intern::Interned;
43 use rustc_data_structures::sync::Lrc;
45 struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
47 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
48 use rustc_hir::def::Namespace::*;
49 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
50 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
51 use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
52 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
53 use rustc_hir::TraitCandidate;
54 use rustc_index::vec::IndexVec;
55 use rustc_metadata::creader::{CStore, CrateLoader};
56 use rustc_middle::metadata::ModChild;
57 use rustc_middle::middle::privacy::AccessLevels;
58 use rustc_middle::ty::query::Providers;
59 use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, ResolverOutputs};
60 use rustc_middle::{bug, span_bug};
61 use rustc_query_system::ich::StableHashingContext;
62 use rustc_session::cstore::{CrateStore, MetadataLoaderDyn};
63 use rustc_session::lint;
64 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
65 use rustc_session::Session;
66 use rustc_span::edition::Edition;
67 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
68 use rustc_span::source_map::Spanned;
69 use rustc_span::symbol::{kw, sym, Ident, Symbol};
70 use rustc_span::{Span, DUMMY_SP};
72 use smallvec::{smallvec, SmallVec};
73 use std::cell::{Cell, RefCell};
74 use std::collections::BTreeSet;
75 use std::{cmp, fmt, mem, ptr};
78 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
79 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
80 use imports::{Import, ImportKind, ImportResolver, NameResolution};
81 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
82 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
84 use crate::access_levels::AccessLevelsVisitor;
86 type Res = def::Res<NodeId>;
89 mod build_reduced_graph;
102 #[derive(Copy, Clone, PartialEq, Debug)]
103 pub enum Determinacy {
109 fn determined(determined: bool) -> Determinacy {
110 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
114 /// A specific scope in which a name can be looked up.
115 /// This enum is currently used only for early resolution (imports and macros),
116 /// but not for late resolution yet.
117 #[derive(Clone, Copy)]
119 DeriveHelpers(LocalExpnId),
121 MacroRules(MacroRulesScopeRef<'a>),
123 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
124 // lint if it should be reported.
125 Module(Module<'a>, Option<NodeId>),
135 /// Names from different contexts may want to visit different subsets of all specific scopes
136 /// with different restrictions when looking up the resolution.
137 /// This enum is currently used only for early resolution (imports and macros),
138 /// but not for late resolution yet.
139 #[derive(Clone, Copy)]
141 /// All scopes with the given namespace.
142 All(Namespace, /*is_import*/ bool),
143 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
144 AbsolutePath(Namespace),
145 /// All scopes with macro namespace and the given macro kind restriction.
147 /// All scopes with the given namespace, used for partially performing late resolution.
148 /// The node id enables lints and is used for reporting them.
149 Late(Namespace, Module<'a>, Option<NodeId>),
152 /// Everything you need to know about a name's location to resolve it.
153 /// Serves as a starting point for the scope visitor.
154 /// This struct is currently used only for early resolution (imports and macros),
155 /// but not for late resolution yet.
156 #[derive(Clone, Copy, Debug)]
157 pub struct ParentScope<'a> {
159 expansion: LocalExpnId,
160 macro_rules: MacroRulesScopeRef<'a>,
161 derives: &'a [ast::Path],
164 impl<'a> ParentScope<'a> {
165 /// Creates a parent scope with the passed argument used as the module scope component,
166 /// and other scope components set to default empty values.
167 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
170 expansion: LocalExpnId::ROOT,
171 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
177 #[derive(Copy, Debug, Clone)]
178 enum ImplTraitContext {
180 Universal(LocalDefId),
184 struct BindingError {
186 origin: BTreeSet<Span>,
187 target: BTreeSet<Span>,
191 impl PartialOrd for BindingError {
192 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
193 Some(self.cmp(other))
197 impl PartialEq for BindingError {
198 fn eq(&self, other: &BindingError) -> bool {
199 self.name == other.name
203 impl Ord for BindingError {
204 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
205 self.name.cmp(&other.name)
209 enum ResolutionError<'a> {
210 /// Error E0401: can't use type or const parameters from outer function.
211 GenericParamsFromOuterFunction(Res, HasGenericParams),
212 /// Error E0403: the name is already used for a type or const parameter in this generic
214 NameAlreadyUsedInParameterList(Symbol, Span),
215 /// Error E0407: method is not a member of trait.
216 MethodNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
217 /// Error E0437: type is not a member of trait.
218 TypeNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
219 /// Error E0438: const is not a member of trait.
220 ConstNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
221 /// Error E0408: variable `{}` is not bound in all patterns.
222 VariableNotBoundInPattern(&'a BindingError),
223 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
224 VariableBoundWithDifferentMode(Symbol, Span),
225 /// Error E0415: identifier is bound more than once in this parameter list.
226 IdentifierBoundMoreThanOnceInParameterList(Symbol),
227 /// Error E0416: identifier is bound more than once in the same pattern.
228 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
229 /// Error E0426: use of undeclared label.
230 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
231 /// Error E0429: `self` imports are only allowed within a `{ }` list.
232 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
233 /// Error E0430: `self` import can only appear once in the list.
234 SelfImportCanOnlyAppearOnceInTheList,
235 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
236 SelfImportOnlyInImportListWithNonEmptyPrefix,
237 /// Error E0433: failed to resolve.
238 FailedToResolve { label: String, suggestion: Option<Suggestion> },
239 /// Error E0434: can't capture dynamic environment in a fn item.
240 CannotCaptureDynamicEnvironmentInFnItem,
241 /// Error E0435: attempt to use a non-constant value in a constant.
242 AttemptToUseNonConstantValueInConstant(
244 /* suggestion */ &'static str,
245 /* current */ &'static str,
247 /// Error E0530: `X` bindings cannot shadow `Y`s.
248 BindingShadowsSomethingUnacceptable {
249 shadowing_binding_descr: &'static str,
251 participle: &'static str,
252 article: &'static str,
253 shadowed_binding_descr: &'static str,
254 shadowed_binding_span: Span,
256 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
257 ForwardDeclaredGenericParam,
258 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
259 ParamInTyOfConstParam(Symbol),
260 /// generic parameters must not be used inside const evaluations.
262 /// This error is only emitted when using `min_const_generics`.
263 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
264 /// Error E0735: generic parameters with a default cannot use `Self`
265 SelfInGenericParamDefault,
266 /// Error E0767: use of unreachable label
267 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
268 /// Error E0323, E0324, E0325: mismatch between trait item and impl item.
273 trait_item_span: Span,
274 code: rustc_errors::DiagnosticId,
278 enum VisResolutionError<'a> {
279 Relative2018(Span, &'a ast::Path),
281 FailedToResolve(Span, String, Option<Suggestion>),
282 ExpectedFound(Span, String, Res),
287 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
288 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
289 #[derive(Clone, Copy, Debug)]
293 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
294 /// nonsensical suggestions.
295 has_generic_args: bool,
299 fn from_path(path: &Path) -> Vec<Segment> {
300 path.segments.iter().map(|s| s.into()).collect()
303 fn from_ident(ident: Ident) -> Segment {
304 Segment { ident, id: None, has_generic_args: false }
307 fn names_to_string(segments: &[Segment]) -> String {
308 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
312 impl<'a> From<&'a ast::PathSegment> for Segment {
313 fn from(seg: &'a ast::PathSegment) -> Segment {
314 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
319 struct UsePlacementFinder {
320 target_module: NodeId,
321 first_legal_span: Option<Span>,
322 first_use_span: Option<Span>,
325 impl UsePlacementFinder {
326 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
328 UsePlacementFinder { target_module, first_legal_span: None, first_use_span: None };
329 finder.visit_crate(krate);
330 if let Some(use_span) = finder.first_use_span {
331 (Some(use_span), true)
333 (finder.first_legal_span, false)
338 fn is_span_suitable_for_use_injection(s: Span) -> bool {
339 // don't suggest placing a use before the prelude
340 // import or other generated ones
344 fn search_for_any_use_in_items(items: &[P<ast::Item>]) -> Option<Span> {
346 if let ItemKind::Use(..) = item.kind {
347 if is_span_suitable_for_use_injection(item.span) {
348 return Some(item.span.shrink_to_lo());
355 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
356 fn visit_crate(&mut self, c: &Crate) {
357 if self.target_module == CRATE_NODE_ID {
358 let inject = c.spans.inject_use_span;
359 if is_span_suitable_for_use_injection(inject) {
360 self.first_legal_span = Some(inject);
362 self.first_use_span = search_for_any_use_in_items(&c.items);
365 visit::walk_crate(self, c);
369 fn visit_item(&mut self, item: &'tcx ast::Item) {
370 if self.target_module == item.id {
371 if let ItemKind::Mod(_, ModKind::Loaded(items, _inline, mod_spans)) = &item.kind {
372 let inject = mod_spans.inject_use_span;
373 if is_span_suitable_for_use_injection(inject) {
374 self.first_legal_span = Some(inject);
376 self.first_use_span = search_for_any_use_in_items(items);
380 visit::walk_item(self, item);
385 /// An intermediate resolution result.
387 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
388 /// items are visible in their whole block, while `Res`es only from the place they are defined
391 enum LexicalScopeBinding<'a> {
392 Item(&'a NameBinding<'a>),
396 impl<'a> LexicalScopeBinding<'a> {
397 fn res(self) -> Res {
399 LexicalScopeBinding::Item(binding) => binding.res(),
400 LexicalScopeBinding::Res(res) => res,
405 #[derive(Copy, Clone, Debug)]
406 enum ModuleOrUniformRoot<'a> {
410 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
411 CrateRootAndExternPrelude,
413 /// Virtual module that denotes resolution in extern prelude.
414 /// Used for paths starting with `::` on 2018 edition.
417 /// Virtual module that denotes resolution in current scope.
418 /// Used only for resolving single-segment imports. The reason it exists is that import paths
419 /// are always split into two parts, the first of which should be some kind of module.
423 impl ModuleOrUniformRoot<'_> {
424 fn same_def(lhs: Self, rhs: Self) -> bool {
426 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
430 ModuleOrUniformRoot::CrateRootAndExternPrelude,
431 ModuleOrUniformRoot::CrateRootAndExternPrelude,
433 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
434 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
440 #[derive(Clone, Debug)]
441 enum PathResult<'a> {
442 Module(ModuleOrUniformRoot<'a>),
443 NonModule(PartialRes),
448 suggestion: Option<Suggestion>,
449 is_error_from_last_segment: bool,
453 impl<'a> PathResult<'a> {
456 is_error_from_last_segment: bool,
458 label_and_suggestion: impl FnOnce() -> (String, Option<Suggestion>),
459 ) -> PathResult<'a> {
460 let (label, suggestion) =
461 if finalize { label_and_suggestion() } else { (String::new(), None) };
462 PathResult::Failed { span, label, suggestion, is_error_from_last_segment }
468 /// An anonymous module; e.g., just a block.
473 /// { // This is an anonymous module
474 /// f(); // This resolves to (2) as we are inside the block.
477 /// f(); // Resolves to (1)
481 /// Any module with a name.
485 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
486 /// or the crate root (which is conceptually a top-level module).
487 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
488 /// * A trait or an enum (it implicitly contains associated types, methods and variant
490 Def(DefKind, DefId, Symbol),
494 /// Get name of the module.
495 pub fn name(&self) -> Option<Symbol> {
497 ModuleKind::Block(..) => None,
498 ModuleKind::Def(.., name) => Some(*name),
503 /// A key that identifies a binding in a given `Module`.
505 /// Multiple bindings in the same module can have the same key (in a valid
506 /// program) if all but one of them come from glob imports.
507 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
509 /// The identifier for the binding, always the `normalize_to_macros_2_0` version of the
513 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
514 /// `_` in the expanded AST that introduced this binding.
518 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
520 /// One node in the tree of modules.
522 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
525 /// * crate root (aka, top-level anonymous module)
528 /// * curly-braced block with statements
530 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
531 pub struct ModuleData<'a> {
532 /// The direct parent module (it may not be a `mod`, however).
533 parent: Option<Module<'a>>,
534 /// What kind of module this is, because this may not be a `mod`.
537 /// Mapping between names and their (possibly in-progress) resolutions in this module.
538 /// Resolutions in modules from other crates are not populated until accessed.
539 lazy_resolutions: Resolutions<'a>,
540 /// True if this is a module from other crate that needs to be populated on access.
541 populate_on_access: Cell<bool>,
543 /// Macro invocations that can expand into items in this module.
544 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
546 /// Whether `#[no_implicit_prelude]` is active.
547 no_implicit_prelude: bool,
549 glob_importers: RefCell<Vec<&'a Import<'a>>>,
550 globs: RefCell<Vec<&'a Import<'a>>>,
552 /// Used to memoize the traits in this module for faster searches through all traits in scope.
553 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
555 /// Span of the module itself. Used for error reporting.
561 type Module<'a> = &'a ModuleData<'a>;
563 impl<'a> ModuleData<'a> {
565 parent: Option<Module<'a>>,
569 no_implicit_prelude: bool,
571 let is_foreign = match kind {
572 ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
573 ModuleKind::Block(_) => false,
578 lazy_resolutions: Default::default(),
579 populate_on_access: Cell::new(is_foreign),
580 unexpanded_invocations: Default::default(),
582 glob_importers: RefCell::new(Vec::new()),
583 globs: RefCell::new(Vec::new()),
584 traits: RefCell::new(None),
590 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
592 R: AsMut<Resolver<'a>>,
593 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
595 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
596 if let Some(binding) = name_resolution.borrow().binding {
597 f(resolver, key.ident, key.ns, binding);
602 /// This modifies `self` in place. The traits will be stored in `self.traits`.
603 fn ensure_traits<R>(&'a self, resolver: &mut R)
605 R: AsMut<Resolver<'a>>,
607 let mut traits = self.traits.borrow_mut();
608 if traits.is_none() {
609 let mut collected_traits = Vec::new();
610 self.for_each_child(resolver, |_, name, ns, binding| {
614 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
615 collected_traits.push((name, binding))
618 *traits = Some(collected_traits.into_boxed_slice());
622 fn res(&self) -> Option<Res> {
624 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
629 // Public for rustdoc.
630 pub fn def_id(&self) -> DefId {
631 self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
634 fn opt_def_id(&self) -> Option<DefId> {
636 ModuleKind::Def(_, def_id, _) => Some(def_id),
641 // `self` resolves to the first module ancestor that `is_normal`.
642 fn is_normal(&self) -> bool {
643 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
646 fn is_trait(&self) -> bool {
647 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
650 fn nearest_item_scope(&'a self) -> Module<'a> {
652 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
653 self.parent.expect("enum or trait module without a parent")
659 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
660 /// This may be the crate root.
661 fn nearest_parent_mod(&self) -> DefId {
663 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
664 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
668 fn is_ancestor_of(&self, mut other: &Self) -> bool {
669 while !ptr::eq(self, other) {
670 if let Some(parent) = other.parent {
680 impl<'a> fmt::Debug for ModuleData<'a> {
681 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
682 write!(f, "{:?}", self.res())
686 /// Records a possibly-private value, type, or module definition.
687 #[derive(Clone, Debug)]
688 pub struct NameBinding<'a> {
689 kind: NameBindingKind<'a>,
690 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
691 expansion: LocalExpnId,
696 pub trait ToNameBinding<'a> {
697 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
700 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
701 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
706 #[derive(Clone, Debug)]
707 enum NameBindingKind<'a> {
708 Res(Res, /* is_macro_export */ bool),
710 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
713 impl<'a> NameBindingKind<'a> {
714 /// Is this a name binding of an import?
715 fn is_import(&self) -> bool {
716 matches!(*self, NameBindingKind::Import { .. })
720 struct PrivacyError<'a> {
722 binding: &'a NameBinding<'a>,
726 struct UseError<'a> {
727 err: DiagnosticBuilder<'a, ErrorGuaranteed>,
728 /// Candidates which user could `use` to access the missing type.
729 candidates: Vec<ImportSuggestion>,
730 /// The `DefId` of the module to place the use-statements in.
732 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
734 /// Extra free-form suggestion.
735 suggestion: Option<(Span, &'static str, String, Applicability)>,
738 #[derive(Clone, Copy, PartialEq, Debug)]
743 MacroRulesVsModularized,
751 fn descr(self) -> &'static str {
753 AmbiguityKind::Import => "multiple potential import sources",
754 AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute",
755 AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute",
756 AmbiguityKind::MacroRulesVsModularized => {
757 "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module"
759 AmbiguityKind::GlobVsOuter => {
760 "a conflict between a name from a glob import and an outer scope during import or macro resolution"
762 AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module",
763 AmbiguityKind::GlobVsExpanded => {
764 "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution"
766 AmbiguityKind::MoreExpandedVsOuter => {
767 "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution"
773 /// Miscellaneous bits of metadata for better ambiguity error reporting.
774 #[derive(Clone, Copy, PartialEq)]
775 enum AmbiguityErrorMisc {
782 struct AmbiguityError<'a> {
785 b1: &'a NameBinding<'a>,
786 b2: &'a NameBinding<'a>,
787 misc1: AmbiguityErrorMisc,
788 misc2: AmbiguityErrorMisc,
791 impl<'a> NameBinding<'a> {
792 fn module(&self) -> Option<Module<'a>> {
794 NameBindingKind::Module(module) => Some(module),
795 NameBindingKind::Import { binding, .. } => binding.module(),
800 fn res(&self) -> Res {
802 NameBindingKind::Res(res, _) => res,
803 NameBindingKind::Module(module) => module.res().unwrap(),
804 NameBindingKind::Import { binding, .. } => binding.res(),
808 fn is_ambiguity(&self) -> bool {
809 self.ambiguity.is_some()
811 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
816 fn is_possibly_imported_variant(&self) -> bool {
818 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
819 NameBindingKind::Res(
820 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
823 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
827 fn is_extern_crate(&self) -> bool {
829 NameBindingKind::Import {
830 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
833 NameBindingKind::Module(&ModuleData {
834 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
836 }) => def_id.index == CRATE_DEF_INDEX,
841 fn is_import(&self) -> bool {
842 matches!(self.kind, NameBindingKind::Import { .. })
845 fn is_glob_import(&self) -> bool {
847 NameBindingKind::Import { import, .. } => import.is_glob(),
852 fn is_importable(&self) -> bool {
855 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
859 fn macro_kind(&self) -> Option<MacroKind> {
860 self.res().macro_kind()
863 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
864 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
865 // Then this function returns `true` if `self` may emerge from a macro *after* that
866 // in some later round and screw up our previously found resolution.
867 // See more detailed explanation in
868 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
871 invoc_parent_expansion: LocalExpnId,
872 binding: &NameBinding<'_>,
874 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
875 // Expansions are partially ordered, so "may appear after" is an inversion of
876 // "certainly appears before or simultaneously" and includes unordered cases.
877 let self_parent_expansion = self.expansion;
878 let other_parent_expansion = binding.expansion;
879 let certainly_before_other_or_simultaneously =
880 other_parent_expansion.is_descendant_of(self_parent_expansion);
881 let certainly_before_invoc_or_simultaneously =
882 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
883 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
887 #[derive(Debug, Default, Clone)]
888 pub struct ExternPreludeEntry<'a> {
889 extern_crate_item: Option<&'a NameBinding<'a>>,
890 pub introduced_by_item: bool,
893 /// Used for better errors for E0773
894 enum BuiltinMacroState {
895 NotYetSeen(SyntaxExtensionKind),
900 resolutions: DeriveResolutions,
901 helper_attrs: Vec<(usize, Ident)>,
902 has_derive_copy: bool,
905 /// The main resolver class.
907 /// This is the visitor that walks the whole crate.
908 pub struct Resolver<'a> {
909 session: &'a Session,
911 definitions: Definitions,
913 graph_root: Module<'a>,
915 prelude: Option<Module<'a>>,
916 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
918 /// N.B., this is used only for better diagnostics, not name resolution itself.
919 has_self: FxHashSet<DefId>,
921 /// Names of fields of an item `DefId` accessible with dot syntax.
922 /// Used for hints during error reporting.
923 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
925 /// All imports known to succeed or fail.
926 determined_imports: Vec<&'a Import<'a>>,
928 /// All non-determined imports.
929 indeterminate_imports: Vec<&'a Import<'a>>,
931 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
932 /// We are resolving a last import segment during import validation.
933 last_import_segment: bool,
934 /// This binding should be ignored during in-module resolution, so that we don't get
935 /// "self-confirming" import resolutions during import validation.
936 unusable_binding: Option<&'a NameBinding<'a>>,
938 // Spans for local variables found during pattern resolution.
939 // Used for suggestions during error reporting.
940 pat_span_map: NodeMap<Span>,
942 /// Resolutions for nodes that have a single resolution.
943 partial_res_map: NodeMap<PartialRes>,
944 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
945 import_res_map: NodeMap<PerNS<Option<Res>>>,
946 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
947 label_res_map: NodeMap<NodeId>,
949 /// `CrateNum` resolutions of `extern crate` items.
950 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
951 reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
952 trait_map: NodeMap<Vec<TraitCandidate>>,
954 /// A map from nodes to anonymous modules.
955 /// Anonymous modules are pseudo-modules that are implicitly created around items
956 /// contained within blocks.
958 /// For example, if we have this:
966 /// There will be an anonymous module created around `g` with the ID of the
967 /// entry block for `f`.
968 block_map: NodeMap<Module<'a>>,
969 /// A fake module that contains no definition and no prelude. Used so that
970 /// some AST passes can generate identifiers that only resolve to local or
972 empty_module: Module<'a>,
973 module_map: FxHashMap<DefId, Module<'a>>,
974 binding_parent_modules: FxHashMap<Interned<'a, NameBinding<'a>>, Module<'a>>,
975 underscore_disambiguator: u32,
977 /// Maps glob imports to the names of items actually imported.
978 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
979 /// Visibilities in "lowered" form, for all entities that have them.
980 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
981 used_imports: FxHashSet<NodeId>,
982 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
983 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
985 /// Privacy errors are delayed until the end in order to deduplicate them.
986 privacy_errors: Vec<PrivacyError<'a>>,
987 /// Ambiguity errors are delayed for deduplication.
988 ambiguity_errors: Vec<AmbiguityError<'a>>,
989 /// `use` injections are delayed for better placement and deduplication.
990 use_injections: Vec<UseError<'a>>,
991 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
992 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
994 arenas: &'a ResolverArenas<'a>,
995 dummy_binding: &'a NameBinding<'a>,
997 crate_loader: CrateLoader<'a>,
998 macro_names: FxHashSet<Ident>,
999 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
1000 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
1001 /// the surface (`macro` items in libcore), but are actually attributes or derives.
1002 builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
1003 registered_attrs: FxHashSet<Ident>,
1004 registered_tools: RegisteredTools,
1005 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
1006 /// FIXME: The only user of this is a doc link resolution hack for rustdoc.
1007 all_macro_rules: FxHashMap<Symbol, Res>,
1008 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1009 dummy_ext_bang: Lrc<SyntaxExtension>,
1010 dummy_ext_derive: Lrc<SyntaxExtension>,
1011 non_macro_attr: Lrc<SyntaxExtension>,
1012 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
1013 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
1014 unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
1015 proc_macro_stubs: FxHashSet<LocalDefId>,
1016 /// Traces collected during macro resolution and validated when it's complete.
1017 single_segment_macro_resolutions:
1018 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
1019 multi_segment_macro_resolutions:
1020 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
1021 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
1022 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
1023 /// Derive macros cannot modify the item themselves and have to store the markers in the global
1024 /// context, so they attach the markers to derive container IDs using this resolver table.
1025 containers_deriving_copy: FxHashSet<LocalExpnId>,
1026 /// Parent scopes in which the macros were invoked.
1027 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
1028 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
1029 /// `macro_rules` scopes *produced* by expanding the macro invocations,
1030 /// include all the `macro_rules` items and other invocations generated by them.
1031 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
1032 /// Helper attributes that are in scope for the given expansion.
1033 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
1034 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
1035 /// with the given `ExpnId`.
1036 derive_data: FxHashMap<LocalExpnId, DeriveData>,
1038 /// Avoid duplicated errors for "name already defined".
1039 name_already_seen: FxHashMap<Symbol, Span>,
1041 potentially_unused_imports: Vec<&'a Import<'a>>,
1043 /// Table for mapping struct IDs into struct constructor IDs,
1044 /// it's not used during normal resolution, only for better error reporting.
1045 /// Also includes of list of each fields visibility
1046 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1048 /// Features enabled for this crate.
1049 active_features: FxHashSet<Symbol>,
1051 lint_buffer: LintBuffer,
1053 next_node_id: NodeId,
1055 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1056 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1058 /// Indices of unnamed struct or variant fields with unresolved attributes.
1059 placeholder_field_indices: FxHashMap<NodeId, usize>,
1060 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1061 /// we know what parent node that fragment should be attached to thanks to this table,
1062 /// and how the `impl Trait` fragments were introduced.
1063 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1065 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1066 /// FIXME: Replace with a more general AST map (together with some other fields).
1067 trait_impl_items: FxHashSet<LocalDefId>,
1069 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1070 /// Amount of lifetime parameters for each item in the crate.
1071 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1073 main_def: Option<MainDefinition>,
1074 trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
1075 /// A list of proc macro LocalDefIds, written out in the order in which
1076 /// they are declared in the static array generated by proc_macro_harness.
1077 proc_macros: Vec<NodeId>,
1078 confused_type_with_std_module: FxHashMap<Span, Span>,
1080 access_levels: AccessLevels,
1083 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1085 pub struct ResolverArenas<'a> {
1086 modules: TypedArena<ModuleData<'a>>,
1087 local_modules: RefCell<Vec<Module<'a>>>,
1088 imports: TypedArena<Import<'a>>,
1089 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1090 ast_paths: TypedArena<ast::Path>,
1091 dropless: DroplessArena,
1094 impl<'a> ResolverArenas<'a> {
1097 parent: Option<Module<'a>>,
1101 no_implicit_prelude: bool,
1102 module_map: &mut FxHashMap<DefId, Module<'a>>,
1105 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1106 let def_id = module.opt_def_id();
1107 if def_id.map_or(true, |def_id| def_id.is_local()) {
1108 self.local_modules.borrow_mut().push(module);
1110 if let Some(def_id) = def_id {
1111 module_map.insert(def_id, module);
1115 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1116 self.local_modules.borrow()
1118 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1119 self.dropless.alloc(name_binding)
1121 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1122 self.imports.alloc(import)
1124 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1125 self.name_resolutions.alloc(Default::default())
1127 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1128 Interned::new_unchecked(self.dropless.alloc(Cell::new(scope)))
1130 fn alloc_macro_rules_binding(
1132 binding: MacroRulesBinding<'a>,
1133 ) -> &'a MacroRulesBinding<'a> {
1134 self.dropless.alloc(binding)
1136 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1137 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1139 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1140 self.dropless.alloc_from_iter(spans)
1144 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1145 fn as_mut(&mut self) -> &mut Resolver<'a> {
1150 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1151 fn parent(self, id: DefId) -> Option<DefId> {
1152 match id.as_local() {
1153 Some(id) => self.definitions.def_key(id).parent,
1154 None => self.cstore().def_key(id).parent,
1156 .map(|index| DefId { index, ..id })
1160 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1161 /// the resolver is no longer needed as all the relevant information is inline.
1162 impl ResolverAstLowering for Resolver<'_> {
1163 fn def_key(&self, id: DefId) -> DefKey {
1164 if let Some(id) = id.as_local() {
1165 self.definitions.def_key(id)
1167 self.cstore().def_key(id)
1172 fn def_span(&self, id: LocalDefId) -> Span {
1173 self.definitions.def_span(id)
1176 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1177 if let Some(def_id) = def_id.as_local() {
1178 self.item_generics_num_lifetimes[&def_id]
1180 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1184 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1185 self.legacy_const_generic_args(expr)
1188 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1189 self.partial_res_map.get(&id).cloned()
1192 fn get_import_res(&self, id: NodeId) -> PerNS<Option<Res>> {
1193 self.import_res_map.get(&id).cloned().unwrap_or_default()
1196 fn get_label_res(&self, id: NodeId) -> Option<NodeId> {
1197 self.label_res_map.get(&id).cloned()
1200 fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
1201 StableHashingContext::new(self.session, &self.definitions, self.crate_loader.cstore())
1204 fn definitions(&self) -> &Definitions {
1208 fn next_node_id(&mut self) -> NodeId {
1212 fn take_trait_map(&mut self, node: NodeId) -> Option<Vec<TraitCandidate>> {
1213 self.trait_map.remove(&node)
1216 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1217 self.node_id_to_def_id.get(&node).copied()
1220 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1221 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1224 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1225 match def_id.as_local() {
1226 Some(def_id) => self.definitions.def_path_hash(def_id),
1227 None => self.cstore().def_path_hash(def_id),
1231 /// Adds a definition with a parent definition.
1235 node_id: ast::NodeId,
1241 !self.node_id_to_def_id.contains_key(&node_id),
1242 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1245 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1248 let def_id = self.definitions.create_def(parent, data, expn_id, span);
1250 // Some things for which we allocate `LocalDefId`s don't correspond to
1251 // anything in the AST, so they don't have a `NodeId`. For these cases
1252 // we don't need a mapping from `NodeId` to `LocalDefId`.
1253 if node_id != ast::DUMMY_NODE_ID {
1254 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1255 self.node_id_to_def_id.insert(node_id, def_id);
1257 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1262 fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind {
1263 self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang)
1267 impl<'a> Resolver<'a> {
1269 session: &'a Session,
1272 metadata_loader: Box<MetadataLoaderDyn>,
1273 arenas: &'a ResolverArenas<'a>,
1275 let root_def_id = CRATE_DEF_ID.to_def_id();
1276 let mut module_map = FxHashMap::default();
1277 let graph_root = arenas.new_module(
1279 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1281 krate.spans.inner_span,
1282 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1285 let empty_module = arenas.new_module(
1287 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1291 &mut FxHashMap::default(),
1294 let definitions = Definitions::new(session.local_stable_crate_id(), krate.spans.inner_span);
1295 let root = definitions.get_root_def();
1297 let mut visibilities = FxHashMap::default();
1298 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1300 let mut def_id_to_node_id = IndexVec::default();
1301 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1302 let mut node_id_to_def_id = FxHashMap::default();
1303 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1305 let mut invocation_parents = FxHashMap::default();
1306 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1308 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1312 .filter(|(_, entry)| entry.add_prelude)
1313 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1316 if !session.contains_name(&krate.attrs, sym::no_core) {
1317 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1318 if !session.contains_name(&krate.attrs, sym::no_std) {
1319 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1323 let (registered_attrs, registered_tools) =
1324 macros::registered_attrs_and_tools(session, &krate.attrs);
1326 let features = session.features_untracked();
1328 let mut resolver = Resolver {
1333 // The outermost module has def ID 0; this is not reflected in the
1339 has_self: FxHashSet::default(),
1340 field_names: FxHashMap::default(),
1342 determined_imports: Vec::new(),
1343 indeterminate_imports: Vec::new(),
1345 last_import_segment: false,
1346 unusable_binding: None,
1348 pat_span_map: Default::default(),
1349 partial_res_map: Default::default(),
1350 import_res_map: Default::default(),
1351 label_res_map: Default::default(),
1352 extern_crate_map: Default::default(),
1353 reexport_map: FxHashMap::default(),
1354 trait_map: NodeMap::default(),
1355 underscore_disambiguator: 0,
1358 block_map: Default::default(),
1359 binding_parent_modules: FxHashMap::default(),
1360 ast_transform_scopes: FxHashMap::default(),
1362 glob_map: Default::default(),
1364 used_imports: FxHashSet::default(),
1365 maybe_unused_trait_imports: Default::default(),
1366 maybe_unused_extern_crates: Vec::new(),
1368 privacy_errors: Vec::new(),
1369 ambiguity_errors: Vec::new(),
1370 use_injections: Vec::new(),
1371 macro_expanded_macro_export_errors: BTreeSet::new(),
1374 dummy_binding: arenas.alloc_name_binding(NameBinding {
1375 kind: NameBindingKind::Res(Res::Err, false),
1377 expansion: LocalExpnId::ROOT,
1379 vis: ty::Visibility::Public,
1382 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1383 macro_names: FxHashSet::default(),
1384 builtin_macros: Default::default(),
1385 builtin_macro_kinds: Default::default(),
1388 macro_use_prelude: FxHashMap::default(),
1389 all_macro_rules: Default::default(),
1390 macro_map: FxHashMap::default(),
1391 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1392 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1393 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1394 invocation_parent_scopes: Default::default(),
1395 output_macro_rules_scopes: Default::default(),
1396 helper_attrs: Default::default(),
1397 derive_data: Default::default(),
1398 local_macro_def_scopes: FxHashMap::default(),
1399 name_already_seen: FxHashMap::default(),
1400 potentially_unused_imports: Vec::new(),
1401 struct_constructors: Default::default(),
1402 unused_macros: Default::default(),
1403 proc_macro_stubs: Default::default(),
1404 single_segment_macro_resolutions: Default::default(),
1405 multi_segment_macro_resolutions: Default::default(),
1406 builtin_attrs: Default::default(),
1407 containers_deriving_copy: Default::default(),
1408 active_features: features
1409 .declared_lib_features
1411 .map(|(feat, ..)| *feat)
1412 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1414 lint_buffer: LintBuffer::default(),
1415 next_node_id: CRATE_NODE_ID,
1418 placeholder_field_indices: Default::default(),
1420 trait_impl_items: Default::default(),
1421 legacy_const_generic_args: Default::default(),
1422 item_generics_num_lifetimes: Default::default(),
1423 main_def: Default::default(),
1424 trait_impls: Default::default(),
1425 proc_macros: Default::default(),
1426 confused_type_with_std_module: Default::default(),
1427 access_levels: Default::default(),
1430 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1431 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1438 parent: Option<Module<'a>>,
1442 no_implicit_prelude: bool,
1444 let module_map = &mut self.module_map;
1445 self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
1448 pub fn next_node_id(&mut self) -> NodeId {
1450 self.next_node_id.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
1451 mem::replace(&mut self.next_node_id, ast::NodeId::from_u32(next))
1454 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1455 &mut self.lint_buffer
1458 pub fn arenas() -> ResolverArenas<'a> {
1462 pub fn into_outputs(self) -> ResolverOutputs {
1463 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1464 let definitions = self.definitions;
1465 let visibilities = self.visibilities;
1466 let extern_crate_map = self.extern_crate_map;
1467 let reexport_map = self.reexport_map;
1468 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1469 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1470 let glob_map = self.glob_map;
1471 let main_def = self.main_def;
1472 let confused_type_with_std_module = self.confused_type_with_std_module;
1473 let access_levels = self.access_levels;
1476 cstore: Box::new(self.crate_loader.into_cstore()),
1482 maybe_unused_trait_imports,
1483 maybe_unused_extern_crates,
1484 extern_prelude: self
1487 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1490 trait_impls: self.trait_impls,
1492 confused_type_with_std_module,
1493 registered_tools: self.registered_tools,
1497 pub fn clone_outputs(&self) -> ResolverOutputs {
1498 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1500 definitions: self.definitions.clone(),
1501 access_levels: self.access_levels.clone(),
1502 cstore: Box::new(self.cstore().clone()),
1503 visibilities: self.visibilities.clone(),
1504 extern_crate_map: self.extern_crate_map.clone(),
1505 reexport_map: self.reexport_map.clone(),
1506 glob_map: self.glob_map.clone(),
1507 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1508 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1509 extern_prelude: self
1512 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1514 main_def: self.main_def,
1515 trait_impls: self.trait_impls.clone(),
1517 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1518 registered_tools: self.registered_tools.clone(),
1522 pub fn cstore(&self) -> &CStore {
1523 self.crate_loader.cstore()
1526 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1528 MacroKind::Bang => self.dummy_ext_bang.clone(),
1529 MacroKind::Derive => self.dummy_ext_derive.clone(),
1530 MacroKind::Attr => self.non_macro_attr.clone(),
1534 /// Runs the function on each namespace.
1535 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1541 fn is_builtin_macro(&mut self, res: Res) -> bool {
1542 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1545 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1547 match ctxt.outer_expn_data().macro_def_id {
1548 Some(def_id) => return def_id,
1549 None => ctxt.remove_mark(),
1554 /// Entry point to crate resolution.
1555 pub fn resolve_crate(&mut self, krate: &Crate) {
1556 self.session.time("resolve_crate", || {
1557 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1558 self.session.time("resolve_access_levels", || {
1559 AccessLevelsVisitor::compute_access_levels(self, krate)
1561 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1562 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1563 self.session.time("resolve_main", || self.resolve_main());
1564 self.session.time("resolve_check_unused", || self.check_unused(krate));
1565 self.session.time("resolve_report_errors", || self.report_errors(krate));
1566 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1570 pub fn traits_in_scope(
1572 current_trait: Option<Module<'a>>,
1573 parent_scope: &ParentScope<'a>,
1574 ctxt: SyntaxContext,
1575 assoc_item: Option<(Symbol, Namespace)>,
1576 ) -> Vec<TraitCandidate> {
1577 let mut found_traits = Vec::new();
1579 if let Some(module) = current_trait {
1580 if self.trait_may_have_item(Some(module), assoc_item) {
1581 let def_id = module.def_id();
1582 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1586 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1588 Scope::Module(module, _) => {
1589 this.traits_in_module(module, assoc_item, &mut found_traits);
1591 Scope::StdLibPrelude => {
1592 if let Some(module) = this.prelude {
1593 this.traits_in_module(module, assoc_item, &mut found_traits);
1596 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1597 _ => unreachable!(),
1605 fn traits_in_module(
1608 assoc_item: Option<(Symbol, Namespace)>,
1609 found_traits: &mut Vec<TraitCandidate>,
1611 module.ensure_traits(self);
1612 let traits = module.traits.borrow();
1613 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1614 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1615 let def_id = trait_binding.res().def_id();
1616 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1617 found_traits.push(TraitCandidate { def_id, import_ids });
1622 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1623 // associated item with the given name and namespace (if specified). This is a conservative
1624 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1625 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1626 // associated items.
1627 fn trait_may_have_item(
1629 trait_module: Option<Module<'a>>,
1630 assoc_item: Option<(Symbol, Namespace)>,
1632 match (trait_module, assoc_item) {
1633 (Some(trait_module), Some((name, ns))) => {
1634 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1635 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1636 assoc_ns == ns && assoc_ident.name == name
1643 fn find_transitive_imports(
1645 mut kind: &NameBindingKind<'_>,
1647 ) -> SmallVec<[LocalDefId; 1]> {
1648 let mut import_ids = smallvec![];
1649 while let NameBindingKind::Import { import, binding, .. } = kind {
1650 let id = self.local_def_id(import.id);
1651 self.maybe_unused_trait_imports.insert(id);
1652 self.add_to_glob_map(&import, trait_name);
1653 import_ids.push(id);
1654 kind = &binding.kind;
1659 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1660 let ident = ident.normalize_to_macros_2_0();
1661 let disambiguator = if ident.name == kw::Underscore {
1662 self.underscore_disambiguator += 1;
1663 self.underscore_disambiguator
1667 BindingKey { ident, ns, disambiguator }
1670 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1671 if module.populate_on_access.get() {
1672 module.populate_on_access.set(false);
1673 self.build_reduced_graph_external(module);
1675 &module.lazy_resolutions
1682 ) -> &'a RefCell<NameResolution<'a>> {
1684 .resolutions(module)
1687 .or_insert_with(|| self.arenas.alloc_name_resolution())
1693 used_binding: &'a NameBinding<'a>,
1694 is_lexical_scope: bool,
1696 if let Some((b2, kind)) = used_binding.ambiguity {
1697 self.ambiguity_errors.push(AmbiguityError {
1702 misc1: AmbiguityErrorMisc::None,
1703 misc2: AmbiguityErrorMisc::None,
1706 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1707 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1708 // but not introduce it, as used if they are accessed from lexical scope.
1709 if is_lexical_scope {
1710 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1711 if let Some(crate_item) = entry.extern_crate_item {
1712 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1719 import.used.set(true);
1720 self.used_imports.insert(import.id);
1721 self.add_to_glob_map(&import, ident);
1722 self.record_use(ident, binding, false);
1727 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1728 if import.is_glob() {
1729 let def_id = self.local_def_id(import.id);
1730 self.glob_map.entry(def_id).or_default().insert(ident.name);
1734 /// A generic scope visitor.
1735 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1736 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1739 scope_set: ScopeSet<'a>,
1740 parent_scope: &ParentScope<'a>,
1741 ctxt: SyntaxContext,
1742 mut visitor: impl FnMut(
1745 /*use_prelude*/ bool,
1749 // General principles:
1750 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1751 // built into the language or standard library. This way we can add new names into the
1752 // language or standard library without breaking user code.
1753 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1754 // Places to search (in order of decreasing priority):
1756 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1757 // (open set, not controlled).
1758 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1759 // (open, not controlled).
1760 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1761 // 4. Tool modules (closed, controlled right now, but not in the future).
1762 // 5. Standard library prelude (de-facto closed, controlled).
1763 // 6. Language prelude (closed, controlled).
1765 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1766 // (open set, not controlled).
1767 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1768 // (open, not controlled).
1769 // 3. Standard library prelude (de-facto closed, controlled).
1771 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1772 // are currently reported as errors. They should be higher in priority than preludes
1773 // and probably even names in modules according to the "general principles" above. They
1774 // also should be subject to restricted shadowing because are effectively produced by
1775 // derives (you need to resolve the derive first to add helpers into scope), but they
1776 // should be available before the derive is expanded for compatibility.
1777 // It's mess in general, so we are being conservative for now.
1778 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1779 // priority than prelude macros, but create ambiguities with macros in modules.
1780 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1781 // (open, not controlled). Have higher priority than prelude macros, but create
1782 // ambiguities with `macro_rules`.
1783 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1784 // 4a. User-defined prelude from macro-use
1785 // (open, the open part is from macro expansions, not controlled).
1786 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1787 // 4c. Standard library prelude (de-facto closed, controlled).
1788 // 6. Language prelude: builtin attributes (closed, controlled).
1790 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1791 let (ns, macro_kind, is_absolute_path) = match scope_set {
1792 ScopeSet::All(ns, _) => (ns, None, false),
1793 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1794 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1795 ScopeSet::Late(ns, ..) => (ns, None, false),
1797 let module = match scope_set {
1798 // Start with the specified module.
1799 ScopeSet::Late(_, module, _) => module,
1800 // Jump out of trait or enum modules, they do not act as scopes.
1801 _ => parent_scope.module.nearest_item_scope(),
1803 let mut scope = match ns {
1804 _ if is_absolute_path => Scope::CrateRoot,
1805 TypeNS | ValueNS => Scope::Module(module, None),
1806 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1808 let mut ctxt = ctxt.normalize_to_macros_2_0();
1809 let mut use_prelude = !module.no_implicit_prelude;
1812 let visit = match scope {
1813 // Derive helpers are not in scope when resolving derives in the same container.
1814 Scope::DeriveHelpers(expn_id) => {
1815 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1817 Scope::DeriveHelpersCompat => true,
1818 Scope::MacroRules(macro_rules_scope) => {
1819 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1820 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1821 // As another consequence of this optimization visitors never observe invocation
1822 // scopes for macros that were already expanded.
1823 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1824 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1825 macro_rules_scope.set(next_scope.get());
1832 Scope::CrateRoot => true,
1833 Scope::Module(..) => true,
1834 Scope::RegisteredAttrs => use_prelude,
1835 Scope::MacroUsePrelude => use_prelude || rust_2015,
1836 Scope::BuiltinAttrs => true,
1837 Scope::ExternPrelude => use_prelude || is_absolute_path,
1838 Scope::ToolPrelude => use_prelude,
1839 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1840 Scope::BuiltinTypes => true,
1844 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1845 return break_result;
1849 scope = match scope {
1850 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1851 Scope::DeriveHelpers(expn_id) => {
1852 // Derive helpers are not visible to code generated by bang or derive macros.
1853 let expn_data = expn_id.expn_data();
1854 match expn_data.kind {
1856 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1857 Scope::DeriveHelpersCompat
1859 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1862 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1863 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1864 MacroRulesScope::Binding(binding) => {
1865 Scope::MacroRules(binding.parent_macro_rules_scope)
1867 MacroRulesScope::Invocation(invoc_id) => {
1868 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1870 MacroRulesScope::Empty => Scope::Module(module, None),
1872 Scope::CrateRoot => match ns {
1874 ctxt.adjust(ExpnId::root());
1875 Scope::ExternPrelude
1877 ValueNS | MacroNS => break,
1879 Scope::Module(module, prev_lint_id) => {
1880 use_prelude = !module.no_implicit_prelude;
1881 let derive_fallback_lint_id = match scope_set {
1882 ScopeSet::Late(.., lint_id) => lint_id,
1885 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1886 Some((parent_module, lint_id)) => {
1887 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1890 ctxt.adjust(ExpnId::root());
1892 TypeNS => Scope::ExternPrelude,
1893 ValueNS => Scope::StdLibPrelude,
1894 MacroNS => Scope::RegisteredAttrs,
1899 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1900 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1901 Scope::BuiltinAttrs => break, // nowhere else to search
1902 Scope::ExternPrelude if is_absolute_path => break,
1903 Scope::ExternPrelude => Scope::ToolPrelude,
1904 Scope::ToolPrelude => Scope::StdLibPrelude,
1905 Scope::StdLibPrelude => match ns {
1906 TypeNS => Scope::BuiltinTypes,
1907 ValueNS => break, // nowhere else to search
1908 MacroNS => Scope::BuiltinAttrs,
1910 Scope::BuiltinTypes => break, // nowhere else to search
1917 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1918 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1919 /// `ident` in the first scope that defines it (or None if no scopes define it).
1921 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1922 /// the items are defined in the block. For example,
1925 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1928 /// g(); // This resolves to the local variable `g` since it shadows the item.
1932 /// Invariant: This must only be called during main resolution, not during
1933 /// import resolution.
1934 fn resolve_ident_in_lexical_scope(
1938 parent_scope: &ParentScope<'a>,
1939 finalize_full: Finalize,
1941 ) -> Option<LexicalScopeBinding<'a>> {
1942 assert!(ns == TypeNS || ns == ValueNS);
1943 let orig_ident = ident;
1944 if ident.name == kw::Empty {
1945 return Some(LexicalScopeBinding::Res(Res::Err));
1947 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1948 // FIXME(jseyfried) improve `Self` hygiene
1949 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1950 (empty_span, empty_span)
1951 } else if ns == TypeNS {
1952 let normalized_span = ident.span.normalize_to_macros_2_0();
1953 (normalized_span, normalized_span)
1955 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1957 ident.span = general_span;
1958 let normalized_ident = Ident { span: normalized_span, ..ident };
1960 // Walk backwards up the ribs in scope.
1961 let finalize = finalize_full.path_span();
1962 let mut module = self.graph_root;
1963 for i in (0..ribs.len()).rev() {
1964 debug!("walk rib\n{:?}", ribs[i].bindings);
1965 // Use the rib kind to determine whether we are resolving parameters
1966 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1967 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1968 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1970 // The ident resolves to a type parameter or local variable.
1971 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1976 *original_rib_ident_def,
1981 module = match ribs[i].kind {
1982 ModuleRibKind(module) => module,
1983 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1984 // If an invocation of this macro created `ident`, give up on `ident`
1985 // and switch to `ident`'s source from the macro definition.
1986 ident.span.remove_mark();
1993 ModuleKind::Block(..) => {} // We can see through blocks
1997 let item = self.resolve_ident_in_module_unadjusted(
1998 ModuleOrUniformRoot::Module(module),
2004 if let Ok(binding) = item {
2005 // The ident resolves to an item.
2006 return Some(LexicalScopeBinding::Item(binding));
2009 self.early_resolve_ident_in_lexical_scope(
2011 ScopeSet::Late(ns, module, finalize_full.node_id()),
2017 .map(LexicalScopeBinding::Item)
2020 fn hygienic_lexical_parent(
2023 ctxt: &mut SyntaxContext,
2024 derive_fallback_lint_id: Option<NodeId>,
2025 ) -> Option<(Module<'a>, Option<NodeId>)> {
2026 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2027 return Some((self.expn_def_scope(ctxt.remove_mark()), None));
2030 if let ModuleKind::Block(..) = module.kind {
2031 return Some((module.parent.unwrap().nearest_item_scope(), None));
2034 // We need to support the next case under a deprecation warning
2037 // ---- begin: this comes from a proc macro derive
2038 // mod implementation_details {
2039 // // Note that `MyStruct` is not in scope here.
2040 // impl SomeTrait for MyStruct { ... }
2044 // So we have to fall back to the module's parent during lexical resolution in this case.
2045 if derive_fallback_lint_id.is_some() {
2046 if let Some(parent) = module.parent {
2047 // Inner module is inside the macro, parent module is outside of the macro.
2048 if module.expansion != parent.expansion
2049 && module.expansion.is_descendant_of(parent.expansion)
2051 // The macro is a proc macro derive
2052 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2053 let ext = self.get_macro_by_def_id(def_id);
2054 if ext.builtin_name.is_none()
2055 && ext.macro_kind() == MacroKind::Derive
2056 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2058 return Some((parent, derive_fallback_lint_id));
2068 fn resolve_ident_in_module(
2070 module: ModuleOrUniformRoot<'a>,
2073 parent_scope: &ParentScope<'a>,
2074 finalize: Option<Span>,
2075 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2076 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, finalize)
2077 .map_err(|(determinacy, _)| determinacy)
2080 fn resolve_ident_in_module_ext(
2082 module: ModuleOrUniformRoot<'a>,
2085 parent_scope: &ParentScope<'a>,
2086 finalize: Option<Span>,
2087 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2088 let tmp_parent_scope;
2089 let mut adjusted_parent_scope = parent_scope;
2091 ModuleOrUniformRoot::Module(m) => {
2092 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2094 ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
2095 adjusted_parent_scope = &tmp_parent_scope;
2098 ModuleOrUniformRoot::ExternPrelude => {
2099 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2101 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2105 self.resolve_ident_in_module_unadjusted_ext(
2109 adjusted_parent_scope,
2115 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2116 debug!("resolve_crate_root({:?})", ident);
2117 let mut ctxt = ident.span.ctxt();
2118 let mark = if ident.name == kw::DollarCrate {
2119 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2120 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2121 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2122 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2123 // definitions actually produced by `macro` and `macro` definitions produced by
2124 // `macro_rules!`, but at least such configurations are not stable yet.
2125 ctxt = ctxt.normalize_to_macro_rules();
2127 "resolve_crate_root: marks={:?}",
2128 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2130 let mut iter = ctxt.marks().into_iter().rev().peekable();
2131 let mut result = None;
2132 // Find the last opaque mark from the end if it exists.
2133 while let Some(&(mark, transparency)) = iter.peek() {
2134 if transparency == Transparency::Opaque {
2135 result = Some(mark);
2142 "resolve_crate_root: found opaque mark {:?} {:?}",
2144 result.map(|r| r.expn_data())
2146 // Then find the last semi-transparent mark from the end if it exists.
2147 for (mark, transparency) in iter {
2148 if transparency == Transparency::SemiTransparent {
2149 result = Some(mark);
2155 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2157 result.map(|r| r.expn_data())
2161 debug!("resolve_crate_root: not DollarCrate");
2162 ctxt = ctxt.normalize_to_macros_2_0();
2163 ctxt.adjust(ExpnId::root())
2165 let module = match mark {
2166 Some(def) => self.expn_def_scope(def),
2169 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2172 return self.graph_root;
2175 let module = self.expect_module(
2176 module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(),
2179 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2188 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2189 let mut module = self.expect_module(module.nearest_parent_mod());
2190 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2191 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
2192 module = self.expect_module(parent.nearest_parent_mod());
2200 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2201 parent_scope: &ParentScope<'a>,
2203 ) -> PathResult<'a> {
2204 self.resolve_path_with_ribs(path, opt_ns, parent_scope, finalize, None)
2207 fn resolve_path_with_ribs(
2210 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2211 parent_scope: &ParentScope<'a>,
2212 finalize_full: Finalize,
2213 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2214 ) -> PathResult<'a> {
2215 debug!("resolve_path(path={:?}, opt_ns={:?}, finalize={:?})", path, opt_ns, finalize_full);
2217 let finalize = finalize_full.path_span();
2218 let mut module = None;
2219 let mut allow_super = true;
2220 let mut second_binding = None;
2222 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2223 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2224 let record_segment_res = |this: &mut Self, res| {
2225 if finalize.is_some() {
2226 if let Some(id) = id {
2227 if !this.partial_res_map.contains_key(&id) {
2228 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2229 this.record_partial_res(id, PartialRes::new(res));
2235 let is_last = i == path.len() - 1;
2236 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2237 let name = ident.name;
2239 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2242 if allow_super && name == kw::Super {
2243 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2244 let self_module = match i {
2245 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2247 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2251 if let Some(self_module) = self_module {
2252 if let Some(parent) = self_module.parent {
2253 module = Some(ModuleOrUniformRoot::Module(
2254 self.resolve_self(&mut ctxt, parent),
2259 return PathResult::failed(ident.span, false, finalize.is_some(), || {
2260 ("there are too many leading `super` keywords".to_string(), None)
2264 if name == kw::SelfLower {
2265 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2266 module = Some(ModuleOrUniformRoot::Module(
2267 self.resolve_self(&mut ctxt, parent_scope.module),
2271 if name == kw::PathRoot && ident.span.rust_2018() {
2272 module = Some(ModuleOrUniformRoot::ExternPrelude);
2275 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2276 // `::a::b` from 2015 macro on 2018 global edition
2277 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2280 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2281 // `::a::b`, `crate::a::b` or `$crate::a::b`
2282 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2288 // Report special messages for path segment keywords in wrong positions.
2289 if ident.is_path_segment_keyword() && i != 0 {
2290 return PathResult::failed(ident.span, false, finalize.is_some(), || {
2291 let name_str = if name == kw::PathRoot {
2292 "crate root".to_string()
2294 format!("`{}`", name)
2296 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2297 format!("global paths cannot start with {}", name_str)
2299 format!("{} in paths can only be used in start position", name_str)
2305 enum FindBindingResult<'a> {
2306 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2307 PathResult(PathResult<'a>),
2309 let find_binding_in_ns = |this: &mut Self, ns| {
2310 let binding = if let Some(module) = module {
2311 this.resolve_ident_in_module(module, ident, ns, parent_scope, finalize)
2312 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2313 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2314 this.early_resolve_ident_in_lexical_scope(
2322 match this.resolve_ident_in_lexical_scope(
2329 // we found a locally-imported or available item/module
2330 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2331 // we found a local variable or type param
2332 Some(LexicalScopeBinding::Res(res))
2333 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2335 record_segment_res(this, res);
2336 return FindBindingResult::PathResult(PathResult::NonModule(
2337 PartialRes::with_unresolved_segments(res, path.len() - 1),
2340 _ => Err(Determinacy::determined(finalize.is_some())),
2343 FindBindingResult::Binding(binding)
2345 let binding = match find_binding_in_ns(self, ns) {
2346 FindBindingResult::PathResult(x) => return x,
2347 FindBindingResult::Binding(binding) => binding,
2352 second_binding = Some(binding);
2354 let res = binding.res();
2355 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2356 if let Some(next_module) = binding.module() {
2357 module = Some(ModuleOrUniformRoot::Module(next_module));
2358 record_segment_res(self, res);
2359 } else if res == Res::ToolMod && i + 1 != path.len() {
2360 if binding.is_import() {
2364 "cannot use a tool module through an import",
2366 .span_note(binding.span, "the tool module imported here")
2369 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2370 return PathResult::NonModule(PartialRes::new(res));
2371 } else if res == Res::Err {
2372 return PathResult::NonModule(PartialRes::new(Res::Err));
2373 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2374 self.lint_if_path_starts_with_module(finalize_full, path, second_binding);
2375 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2380 return PathResult::failed(ident.span, is_last, finalize.is_some(), || {
2381 let label = format!(
2382 "`{ident}` is {} {}, not a module",
2390 Err(Undetermined) => return PathResult::Indeterminate,
2391 Err(Determined) => {
2392 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2393 if opt_ns.is_some() && !module.is_normal() {
2394 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2395 module.res().unwrap(),
2401 return PathResult::failed(ident.span, is_last, finalize.is_some(), || {
2402 let module_res = match module {
2403 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2406 if module_res == self.graph_root.res() {
2407 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2408 let mut candidates =
2409 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod);
2410 candidates.sort_by_cached_key(|c| {
2411 (c.path.segments.len(), pprust::path_to_string(&c.path))
2413 if let Some(candidate) = candidates.get(0) {
2415 String::from("unresolved import"),
2417 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2418 String::from("a similar path exists"),
2419 Applicability::MaybeIncorrect,
2422 } else if self.session.edition() == Edition::Edition2015 {
2423 (format!("maybe a missing crate `{}`?", ident), None)
2425 (format!("could not find `{}` in the crate root", ident), None)
2433 .map_or(false, |c| c.is_ascii_uppercase())
2435 // Check whether the name refers to an item in the value namespace.
2436 let suggestion = if ribs.is_some() {
2437 let match_span = match self.resolve_ident_in_lexical_scope(
2442 &ribs.unwrap()[ValueNS],
2444 // Name matches a local variable. For example:
2447 // let Foo: &str = "";
2448 // println!("{}", Foo::Bar); // Name refers to local
2449 // // variable `Foo`.
2452 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2453 Some(*self.pat_span_map.get(&id).unwrap())
2456 // Name matches item from a local name binding
2457 // created by `use` declaration. For example:
2459 // pub Foo: &str = "";
2463 // println!("{}", Foo::Bar); // Name refers to local
2464 // // binding `Foo`.
2467 Some(LexicalScopeBinding::Item(name_binding)) => {
2468 Some(name_binding.span)
2473 if let Some(span) = match_span {
2475 vec![(span, String::from(""))],
2477 "`{}` is defined here, but is not a type",
2480 Applicability::MaybeIncorrect,
2489 (format!("use of undeclared type `{}`", ident), suggestion)
2492 format!("use of undeclared crate or module `{}`", ident),
2493 if ident.name == sym::alloc {
2497 "add `extern crate alloc` to use the `alloc` crate",
2499 Applicability::MaybeIncorrect,
2502 self.find_similarly_named_module_or_crate(
2504 &parent_scope.module,
2508 vec![(ident.span, sugg.to_string())],
2510 "there is a crate or module with a similar name",
2512 Applicability::MaybeIncorrect,
2519 let parent = path[i - 1].ident.name;
2520 let parent = match parent {
2521 // ::foo is mounted at the crate root for 2015, and is the extern
2522 // prelude for 2018+
2523 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2524 "the list of imported crates".to_owned()
2526 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2528 format!("`{}`", parent)
2532 let mut msg = format!("could not find `{}` in {}", ident, parent);
2533 if ns == TypeNS || ns == ValueNS {
2534 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2535 if let FindBindingResult::Binding(Ok(binding)) =
2536 find_binding_in_ns(self, ns_to_try)
2538 let mut found = |what| {
2540 "expected {}, found {} `{}` in {}",
2547 if binding.module().is_some() {
2550 match binding.res() {
2551 def::Res::<NodeId>::Def(kind, id) => {
2552 found(kind.descr(id))
2554 _ => found(ns_to_try.descr()),
2566 self.lint_if_path_starts_with_module(finalize_full, path, second_binding);
2568 PathResult::Module(match module {
2569 Some(module) => module,
2570 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2571 _ => bug!("resolve_path: non-empty path `{:?}` has no module", path),
2575 fn lint_if_path_starts_with_module(
2579 second_binding: Option<&NameBinding<'_>>,
2581 let (diag_id, diag_span) = match finalize {
2582 Finalize::No => return,
2583 Finalize::SimplePath(id, path_span) => (id, path_span),
2584 Finalize::UsePath { root_id, root_span, .. } => (root_id, root_span),
2585 Finalize::QPathTrait { qpath_id, qpath_span, .. } => (qpath_id, qpath_span),
2588 let first_name = match path.get(0) {
2589 // In the 2018 edition this lint is a hard error, so nothing to do
2590 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2594 // We're only interested in `use` paths which should start with
2595 // `{{root}}` currently.
2596 if first_name != kw::PathRoot {
2601 // If this import looks like `crate::...` it's already good
2602 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2603 // Otherwise go below to see if it's an extern crate
2605 // If the path has length one (and it's `PathRoot` most likely)
2606 // then we don't know whether we're gonna be importing a crate or an
2607 // item in our crate. Defer this lint to elsewhere
2611 // If the first element of our path was actually resolved to an
2612 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2613 // warning, this looks all good!
2614 if let Some(binding) = second_binding {
2615 if let NameBindingKind::Import { import, .. } = binding.kind {
2616 // Careful: we still want to rewrite paths from renamed extern crates.
2617 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2623 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2624 self.lint_buffer.buffer_lint_with_diagnostic(
2625 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2628 "absolute paths must start with `self`, `super`, \
2629 `crate`, or an external crate name in the 2018 edition",
2634 // Validate a local resolution (from ribs).
2635 fn validate_res_from_ribs(
2640 finalize: Option<Span>,
2641 original_rib_ident_def: Ident,
2642 all_ribs: &[Rib<'a>],
2644 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2645 debug!("validate_res_from_ribs({:?})", res);
2646 let ribs = &all_ribs[rib_index + 1..];
2648 // An invalid forward use of a generic parameter from a previous default.
2649 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2650 if let Some(span) = finalize {
2651 let res_error = if rib_ident.name == kw::SelfUpper {
2652 ResolutionError::SelfInGenericParamDefault
2654 ResolutionError::ForwardDeclaredGenericParam
2656 self.report_error(span, res_error);
2658 assert_eq!(res, Res::Err);
2664 use ResolutionError::*;
2665 let mut res_err = None;
2670 | ClosureOrAsyncRibKind
2672 | MacroDefinition(..)
2673 | ForwardGenericParamBanRibKind => {
2674 // Nothing to do. Continue.
2676 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2677 // This was an attempt to access an upvar inside a
2678 // named function item. This is not allowed, so we
2680 if let Some(span) = finalize {
2681 // We don't immediately trigger a resolve error, because
2682 // we want certain other resolution errors (namely those
2683 // emitted for `ConstantItemRibKind` below) to take
2685 res_err = Some((span, CannotCaptureDynamicEnvironmentInFnItem));
2688 ConstantItemRibKind(_, item) => {
2689 // Still doesn't deal with upvars
2690 if let Some(span) = finalize {
2691 let (span, resolution_error) =
2692 if let Some((ident, constant_item_kind)) = item {
2693 let kind_str = match constant_item_kind {
2694 ConstantItemKind::Const => "const",
2695 ConstantItemKind::Static => "static",
2699 AttemptToUseNonConstantValueInConstant(
2700 ident, "let", kind_str,
2706 AttemptToUseNonConstantValueInConstant(
2707 original_rib_ident_def,
2713 self.report_error(span, resolution_error);
2717 ConstParamTyRibKind => {
2718 if let Some(span) = finalize {
2719 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2725 if let Some((span, res_err)) = res_err {
2726 self.report_error(span, res_err);
2730 Res::Def(DefKind::TyParam, _) | Res::SelfTy { .. } => {
2732 let has_generic_params: HasGenericParams = match rib.kind {
2734 | ClosureOrAsyncRibKind
2737 | MacroDefinition(..)
2738 | ForwardGenericParamBanRibKind => {
2739 // Nothing to do. Continue.
2743 ConstantItemRibKind(trivial, _) => {
2744 let features = self.session.features_untracked();
2745 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2746 if !(trivial || features.generic_const_exprs) {
2747 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2748 // we can't easily tell if it's generic at this stage, so we instead remember
2749 // this and then enforce the self type to be concrete later on.
2750 if let Res::SelfTy { trait_, alias_to: Some((def, _)) } = res {
2751 res = Res::SelfTy { trait_, alias_to: Some((def, true)) }
2753 if let Some(span) = finalize {
2756 ResolutionError::ParamInNonTrivialAnonConst {
2757 name: rib_ident.name,
2761 self.session.delay_span_bug(span, CG_BUG_STR);
2771 // This was an attempt to use a type parameter outside its scope.
2772 ItemRibKind(has_generic_params) => has_generic_params,
2773 FnItemRibKind => HasGenericParams::Yes,
2774 ConstParamTyRibKind => {
2775 if let Some(span) = finalize {
2778 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2785 if let Some(span) = finalize {
2788 ResolutionError::GenericParamsFromOuterFunction(
2797 Res::Def(DefKind::ConstParam, _) => {
2798 let mut ribs = ribs.iter().peekable();
2799 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2800 // When declaring const parameters inside function signatures, the first rib
2801 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2802 // (spuriously) conflicting with the const param.
2807 let has_generic_params = match rib.kind {
2809 | ClosureOrAsyncRibKind
2812 | MacroDefinition(..)
2813 | ForwardGenericParamBanRibKind => continue,
2815 ConstantItemRibKind(trivial, _) => {
2816 let features = self.session.features_untracked();
2817 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2818 if !(trivial || features.generic_const_exprs) {
2819 if let Some(span) = finalize {
2822 ResolutionError::ParamInNonTrivialAnonConst {
2823 name: rib_ident.name,
2827 self.session.delay_span_bug(span, CG_BUG_STR);
2836 ItemRibKind(has_generic_params) => has_generic_params,
2837 FnItemRibKind => HasGenericParams::Yes,
2838 ConstParamTyRibKind => {
2839 if let Some(span) = finalize {
2842 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2849 // This was an attempt to use a const parameter outside its scope.
2850 if let Some(span) = finalize {
2853 ResolutionError::GenericParamsFromOuterFunction(
2867 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2868 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2869 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2870 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2874 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2875 debug!("(recording pat) recording {:?} for {:?}", node, span);
2876 self.pat_span_map.insert(node, span);
2879 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2880 vis.is_accessible_from(module.nearest_parent_mod(), self)
2883 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2884 if let Some(old_module) =
2885 self.binding_parent_modules.insert(Interned::new_unchecked(binding), module)
2887 if !ptr::eq(module, old_module) {
2888 span_bug!(binding.span, "parent module is reset for binding");
2893 fn disambiguate_macro_rules_vs_modularized(
2895 macro_rules: &'a NameBinding<'a>,
2896 modularized: &'a NameBinding<'a>,
2898 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2899 // is disambiguated to mitigate regressions from macro modularization.
2900 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2902 self.binding_parent_modules.get(&Interned::new_unchecked(macro_rules)),
2903 self.binding_parent_modules.get(&Interned::new_unchecked(modularized)),
2905 (Some(macro_rules), Some(modularized)) => {
2906 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
2907 && modularized.is_ancestor_of(macro_rules)
2913 fn report_errors(&mut self, krate: &Crate) {
2914 self.report_with_use_injections(krate);
2916 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2917 let msg = "macro-expanded `macro_export` macros from the current crate \
2918 cannot be referred to by absolute paths";
2919 self.lint_buffer.buffer_lint_with_diagnostic(
2920 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2924 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2928 for ambiguity_error in &self.ambiguity_errors {
2929 self.report_ambiguity_error(ambiguity_error);
2932 let mut reported_spans = FxHashSet::default();
2933 for error in &self.privacy_errors {
2934 if reported_spans.insert(error.dedup_span) {
2935 self.report_privacy_error(error);
2940 fn report_with_use_injections(&mut self, krate: &Crate) {
2941 for UseError { mut err, candidates, def_id, instead, suggestion } in
2942 self.use_injections.drain(..)
2944 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2945 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2949 if !candidates.is_empty() {
2950 diagnostics::show_candidates(
2959 } else if let Some((span, msg, sugg, appl)) = suggestion {
2960 err.span_suggestion(span, msg, sugg, appl);
2966 fn report_conflict<'b>(
2971 new_binding: &NameBinding<'b>,
2972 old_binding: &NameBinding<'b>,
2974 // Error on the second of two conflicting names
2975 if old_binding.span.lo() > new_binding.span.lo() {
2976 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2979 let container = match parent.kind {
2980 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
2981 ModuleKind::Block(..) => "block",
2984 let old_noun = match old_binding.is_import() {
2986 false => "definition",
2989 let new_participle = match new_binding.is_import() {
2995 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2997 if let Some(s) = self.name_already_seen.get(&name) {
3003 let old_kind = match (ns, old_binding.module()) {
3004 (ValueNS, _) => "value",
3005 (MacroNS, _) => "macro",
3006 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3007 (TypeNS, Some(module)) if module.is_normal() => "module",
3008 (TypeNS, Some(module)) if module.is_trait() => "trait",
3009 (TypeNS, _) => "type",
3012 let msg = format!("the name `{}` is defined multiple times", name);
3014 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3015 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3016 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3017 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3018 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3020 _ => match (old_binding.is_import(), new_binding.is_import()) {
3021 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3022 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3023 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3028 "`{}` must be defined only once in the {} namespace of this {}",
3034 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3036 self.session.source_map().guess_head_span(old_binding.span),
3037 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3040 // See https://github.com/rust-lang/rust/issues/32354
3041 use NameBindingKind::Import;
3042 let import = match (&new_binding.kind, &old_binding.kind) {
3043 // If there are two imports where one or both have attributes then prefer removing the
3044 // import without attributes.
3045 (Import { import: new, .. }, Import { import: old, .. })
3047 !new_binding.span.is_dummy()
3048 && !old_binding.span.is_dummy()
3049 && (new.has_attributes || old.has_attributes)
3052 if old.has_attributes {
3053 Some((new, new_binding.span, true))
3055 Some((old, old_binding.span, true))
3058 // Otherwise prioritize the new binding.
3059 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3060 Some((import, new_binding.span, other.is_import()))
3062 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3063 Some((import, old_binding.span, other.is_import()))
3068 // Check if the target of the use for both bindings is the same.
3069 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3070 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3072 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3073 // Only suggest removing an import if both bindings are to the same def, if both spans
3074 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3075 // been introduced by an item.
3076 let should_remove_import = duplicate
3078 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3081 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3082 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3084 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3085 // Simple case - remove the entire import. Due to the above match arm, this can
3086 // only be a single use so just remove it entirely.
3087 err.tool_only_span_suggestion(
3088 import.use_span_with_attributes,
3089 "remove unnecessary import",
3091 Applicability::MaybeIncorrect,
3094 Some((import, span, _)) => {
3095 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3101 self.name_already_seen.insert(name, span);
3104 /// This function adds a suggestion to change the binding name of a new import that conflicts
3105 /// with an existing import.
3107 /// ```text,ignore (diagnostic)
3108 /// help: you can use `as` to change the binding name of the import
3110 /// LL | use foo::bar as other_bar;
3111 /// | ^^^^^^^^^^^^^^^^^^^^^
3113 fn add_suggestion_for_rename_of_use(
3115 err: &mut Diagnostic,
3117 import: &Import<'_>,
3120 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3121 format!("Other{}", name)
3123 format!("other_{}", name)
3126 let mut suggestion = None;
3128 ImportKind::Single { type_ns_only: true, .. } => {
3129 suggestion = Some(format!("self as {}", suggested_name))
3131 ImportKind::Single { source, .. } => {
3133 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3135 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3136 if pos <= snippet.len() {
3137 suggestion = Some(format!(
3141 if snippet.ends_with(';') { ";" } else { "" }
3147 ImportKind::ExternCrate { source, target } => {
3148 suggestion = Some(format!(
3149 "extern crate {} as {};",
3150 source.unwrap_or(target.name),
3154 _ => unreachable!(),
3157 let rename_msg = "you can use `as` to change the binding name of the import";
3158 if let Some(suggestion) = suggestion {
3159 err.span_suggestion(
3163 Applicability::MaybeIncorrect,
3166 err.span_label(binding_span, rename_msg);
3170 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3171 /// nested. In the following example, this function will be invoked to remove the `a` binding
3172 /// in the second use statement:
3174 /// ```ignore (diagnostic)
3175 /// use issue_52891::a;
3176 /// use issue_52891::{d, a, e};
3179 /// The following suggestion will be added:
3181 /// ```ignore (diagnostic)
3182 /// use issue_52891::{d, a, e};
3183 /// ^-- help: remove unnecessary import
3186 /// If the nested use contains only one import then the suggestion will remove the entire
3189 /// It is expected that the provided import is nested - this isn't checked by the
3190 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3191 /// as characters expected by span manipulations won't be present.
3192 fn add_suggestion_for_duplicate_nested_use(
3194 err: &mut Diagnostic,
3195 import: &Import<'_>,
3198 assert!(import.is_nested());
3199 let message = "remove unnecessary import";
3201 // Two examples will be used to illustrate the span manipulations we're doing:
3203 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3204 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3205 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3206 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3208 let (found_closing_brace, span) =
3209 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3211 // If there was a closing brace then identify the span to remove any trailing commas from
3212 // previous imports.
3213 if found_closing_brace {
3214 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3215 err.tool_only_span_suggestion(
3219 Applicability::MaybeIncorrect,
3222 // Remove the entire line if we cannot extend the span back, this indicates an
3223 // `issue_52891::{self}` case.
3224 err.span_suggestion(
3225 import.use_span_with_attributes,
3228 Applicability::MaybeIncorrect,
3235 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3238 fn extern_prelude_get(&mut self, ident: Ident, finalize: bool) -> Option<&'a NameBinding<'a>> {
3239 if ident.is_path_segment_keyword() {
3240 // Make sure `self`, `super` etc produce an error when passed to here.
3243 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3244 if let Some(binding) = entry.extern_crate_item {
3245 if finalize && entry.introduced_by_item {
3246 self.record_use(ident, binding, false);
3250 let crate_id = if finalize {
3251 let Some(crate_id) =
3252 self.crate_loader.process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
3255 self.crate_loader.maybe_process_path_extern(ident.name)?
3257 let crate_root = self.expect_module(crate_id.as_def_id());
3259 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3260 .to_name_binding(self.arenas),
3266 /// Rustdoc uses this to resolve doc link paths in a recoverable way. `PathResult<'a>`
3267 /// isn't something that can be returned because it can't be made to live that long,
3268 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3269 /// just that an error occurred.
3270 pub fn resolve_rustdoc_path(
3274 mut module_id: DefId,
3277 Vec::from_iter(path_str.split("::").map(Ident::from_str).map(Segment::from_ident));
3278 if let Some(segment) = segments.first_mut() {
3279 if segment.ident.name == kw::Crate {
3280 // FIXME: `resolve_path` always resolves `crate` to the current crate root, but
3281 // rustdoc wants it to resolve to the `module_id`'s crate root. This trick of
3282 // replacing `crate` with `self` and changing the current module should achieve
3284 segment.ident.name = kw::SelfLower;
3285 module_id = module_id.krate.as_def_id();
3286 } else if segment.ident.name == kw::Empty {
3287 segment.ident.name = kw::PathRoot;
3291 let module = self.expect_module(module_id);
3292 match self.resolve_path(
3295 &ParentScope::module(module, self),
3298 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Some(module.res().unwrap()),
3299 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3300 Some(path_res.base_res())
3302 PathResult::Module(ModuleOrUniformRoot::ExternPrelude)
3303 | PathResult::NonModule(..)
3304 | PathResult::Failed { .. } => None,
3305 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3310 pub fn graph_root(&self) -> Module<'a> {
3315 pub fn take_all_macro_rules(&mut self) -> FxHashMap<Symbol, Res> {
3316 mem::take(&mut self.all_macro_rules)
3320 /// For local modules returns only reexports, for external modules returns all children.
3321 pub fn module_children_or_reexports(&self, def_id: DefId) -> Vec<ModChild> {
3322 if let Some(def_id) = def_id.as_local() {
3323 self.reexport_map.get(&def_id).cloned().unwrap_or_default()
3325 self.cstore().module_children_untracked(def_id, self.session)
3329 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3331 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3332 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3335 /// Checks if an expression refers to a function marked with
3336 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3337 /// from the attribute.
3338 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3339 if let ExprKind::Path(None, path) = &expr.kind {
3340 // Don't perform legacy const generics rewriting if the path already
3341 // has generic arguments.
3342 if path.segments.last().unwrap().args.is_some() {
3346 let partial_res = self.partial_res_map.get(&expr.id)?;
3347 if partial_res.unresolved_segments() != 0 {
3351 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3352 // We only support cross-crate argument rewriting. Uses
3353 // within the same crate should be updated to use the new
3354 // const generics style.
3355 if def_id.is_local() {
3359 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3365 .item_attrs_untracked(def_id, self.session)
3366 .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3367 let mut ret = Vec::new();
3368 for meta in attr.meta_item_list()? {
3369 match meta.literal()?.kind {
3370 LitKind::Int(a, _) => ret.push(a as usize),
3371 _ => panic!("invalid arg index"),
3374 // Cache the lookup to avoid parsing attributes for an iterm multiple times.
3375 self.legacy_const_generic_args.insert(def_id, Some(ret.clone()));
3382 fn resolve_main(&mut self) {
3383 let module = self.graph_root;
3384 let ident = Ident::with_dummy_span(sym::main);
3385 let parent_scope = &ParentScope::module(module, self);
3387 let Ok(name_binding) = self.resolve_ident_in_module(
3388 ModuleOrUniformRoot::Module(module),
3397 let res = name_binding.res();
3398 let is_import = name_binding.is_import();
3399 let span = name_binding.span;
3400 if let Res::Def(DefKind::Fn, _) = res {
3401 self.record_use(ident, name_binding, false);
3403 self.main_def = Some(MainDefinition { res, is_import, span });
3407 fn names_to_string(names: &[Symbol]) -> String {
3408 let mut result = String::new();
3409 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3411 result.push_str("::");
3413 if Ident::with_dummy_span(*name).is_raw_guess() {
3414 result.push_str("r#");
3416 result.push_str(name.as_str());
3421 fn path_names_to_string(path: &Path) -> String {
3422 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3425 /// A somewhat inefficient routine to obtain the name of a module.
3426 fn module_to_string(module: Module<'_>) -> Option<String> {
3427 let mut names = Vec::new();
3429 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3430 if let ModuleKind::Def(.., name) = module.kind {
3431 if let Some(parent) = module.parent {
3433 collect_mod(names, parent);
3436 names.push(Symbol::intern("<opaque>"));
3437 collect_mod(names, module.parent.unwrap());
3440 collect_mod(&mut names, module);
3442 if names.is_empty() {
3446 Some(names_to_string(&names))
3449 #[derive(Copy, Clone, Debug)]
3451 /// Do not issue the lint.
3454 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3455 /// In this case, we can take the span of that path.
3456 SimplePath(NodeId, Span),
3458 /// This lint comes from a `use` statement. In this case, what we
3459 /// care about really is the *root* `use` statement; e.g., if we
3460 /// have nested things like `use a::{b, c}`, we care about the
3462 UsePath { root_id: NodeId, root_span: Span, path_span: Span },
3464 /// This is the "trait item" from a fully qualified path. For example,
3465 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3466 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3467 QPathTrait { qpath_id: NodeId, qpath_span: Span, path_span: Span },
3471 fn node_id_and_path_span(&self) -> Option<(NodeId, Span)> {
3473 Finalize::No => None,
3474 Finalize::SimplePath(id, path_span)
3475 | Finalize::UsePath { root_id: id, path_span, .. }
3476 | Finalize::QPathTrait { qpath_id: id, path_span, .. } => Some((id, path_span)),
3480 fn node_id(&self) -> Option<NodeId> {
3481 self.node_id_and_path_span().map(|(id, _)| id)
3484 fn path_span(&self) -> Option<Span> {
3485 self.node_id_and_path_span().map(|(_, path_span)| path_span)
3489 pub fn provide(providers: &mut Providers) {
3490 late::lifetimes::provide(providers);