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)]
17 #![feature(never_type)]
19 #![recursion_limit = "256"]
20 #![allow(rustdoc::private_intra_doc_links)]
21 #![allow(rustc::potential_query_instability)]
26 pub use rustc_hir::def::{Namespace, PerNS};
30 use rustc_arena::{DroplessArena, TypedArena};
31 use rustc_ast::node_id::NodeMap;
32 use rustc_ast::ptr::P;
33 use rustc_ast::visit::{self, Visitor};
34 use rustc_ast::{self as ast, NodeId};
35 use rustc_ast::{Crate, CRATE_NODE_ID};
36 use rustc_ast::{Expr, ExprKind, LitKind};
37 use rustc_ast::{ItemKind, ModKind, Path};
38 use rustc_ast_lowering::ResolverAstLowering;
39 use rustc_ast_pretty::pprust;
40 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
41 use rustc_data_structures::intern::Interned;
42 use rustc_data_structures::sync::Lrc;
44 struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
46 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
47 use rustc_hir::def::Namespace::*;
48 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
49 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
50 use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
51 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
52 use rustc_hir::TraitCandidate;
53 use rustc_index::vec::IndexVec;
54 use rustc_metadata::creader::{CStore, CrateLoader};
55 use rustc_middle::metadata::ModChild;
56 use rustc_middle::middle::privacy::AccessLevels;
57 use rustc_middle::span_bug;
58 use rustc_middle::ty::query::Providers;
59 use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, ResolverOutputs};
60 use rustc_query_system::ich::StableHashingContext;
61 use rustc_session::cstore::{CrateStore, MetadataLoaderDyn};
62 use rustc_session::lint;
63 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
64 use rustc_session::Session;
65 use rustc_span::edition::Edition;
66 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
67 use rustc_span::source_map::Spanned;
68 use rustc_span::symbol::{kw, sym, Ident, Symbol};
69 use rustc_span::{Span, DUMMY_SP};
71 use smallvec::{smallvec, SmallVec};
72 use std::cell::{Cell, RefCell};
73 use std::collections::BTreeSet;
74 use std::ops::ControlFlow;
75 use std::{cmp, fmt, iter, 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() }
318 struct UsePlacementFinder {
319 target_module: NodeId,
324 impl UsePlacementFinder {
325 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
326 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
327 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
328 visit::walk_crate(&mut finder, krate);
330 (finder.span, finder.found_use)
333 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
334 if self.span.is_some() {
335 return ControlFlow::Break(());
337 if node_id != self.target_module {
338 return ControlFlow::Continue(());
340 // find a use statement
343 ItemKind::Use(..) => {
344 // don't suggest placing a use before the prelude
345 // import or other generated ones
346 if !item.span.from_expansion() {
347 self.span = Some(item.span.shrink_to_lo());
348 self.found_use = true;
349 return ControlFlow::Break(());
352 // don't place use before extern crate
353 ItemKind::ExternCrate(_) => {}
354 // but place them before the first other item
356 if self.span.map_or(true, |span| item.span < span)
357 && !item.span.from_expansion()
359 self.span = Some(item.span.shrink_to_lo());
360 // don't insert between attributes and an item
361 // find the first attribute on the item
362 // FIXME: This is broken for active attributes.
363 for attr in &item.attrs {
364 if !attr.span.is_dummy()
365 && self.span.map_or(true, |span| attr.span < span)
367 self.span = Some(attr.span.shrink_to_lo());
374 ControlFlow::Continue(())
378 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
379 fn visit_item(&mut self, item: &'tcx ast::Item) {
380 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
381 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
385 visit::walk_item(self, item);
389 /// An intermediate resolution result.
391 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
392 /// items are visible in their whole block, while `Res`es only from the place they are defined
395 enum LexicalScopeBinding<'a> {
396 Item(&'a NameBinding<'a>),
400 impl<'a> LexicalScopeBinding<'a> {
401 fn res(self) -> Res {
403 LexicalScopeBinding::Item(binding) => binding.res(),
404 LexicalScopeBinding::Res(res) => res,
409 #[derive(Copy, Clone, Debug)]
410 enum ModuleOrUniformRoot<'a> {
414 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
415 CrateRootAndExternPrelude,
417 /// Virtual module that denotes resolution in extern prelude.
418 /// Used for paths starting with `::` on 2018 edition.
421 /// Virtual module that denotes resolution in current scope.
422 /// Used only for resolving single-segment imports. The reason it exists is that import paths
423 /// are always split into two parts, the first of which should be some kind of module.
427 impl ModuleOrUniformRoot<'_> {
428 fn same_def(lhs: Self, rhs: Self) -> bool {
430 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
434 ModuleOrUniformRoot::CrateRootAndExternPrelude,
435 ModuleOrUniformRoot::CrateRootAndExternPrelude,
437 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
438 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
444 #[derive(Clone, Debug)]
445 enum PathResult<'a> {
446 Module(ModuleOrUniformRoot<'a>),
447 NonModule(PartialRes),
452 suggestion: Option<Suggestion>,
453 is_error_from_last_segment: bool,
459 /// An anonymous module; e.g., just a block.
464 /// { // This is an anonymous module
465 /// f(); // This resolves to (2) as we are inside the block.
468 /// f(); // Resolves to (1)
472 /// Any module with a name.
476 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
477 /// or the crate root (which is conceptually a top-level module).
478 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
479 /// * A trait or an enum (it implicitly contains associated types, methods and variant
481 Def(DefKind, DefId, Symbol),
485 /// Get name of the module.
486 pub fn name(&self) -> Option<Symbol> {
488 ModuleKind::Block(..) => None,
489 ModuleKind::Def(.., name) => Some(*name),
494 /// A key that identifies a binding in a given `Module`.
496 /// Multiple bindings in the same module can have the same key (in a valid
497 /// program) if all but one of them come from glob imports.
498 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
500 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
504 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
505 /// `_` in the expanded AST that introduced this binding.
509 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
511 /// One node in the tree of modules.
513 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
516 /// * crate root (aka, top-level anonymous module)
519 /// * curly-braced block with statements
521 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
522 pub struct ModuleData<'a> {
523 /// The direct parent module (it may not be a `mod`, however).
524 parent: Option<Module<'a>>,
525 /// What kind of module this is, because this may not be a `mod`.
528 /// Mapping between names and their (possibly in-progress) resolutions in this module.
529 /// Resolutions in modules from other crates are not populated until accessed.
530 lazy_resolutions: Resolutions<'a>,
531 /// True if this is a module from other crate that needs to be populated on access.
532 populate_on_access: Cell<bool>,
534 /// Macro invocations that can expand into items in this module.
535 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
537 /// Whether `#[no_implicit_prelude]` is active.
538 no_implicit_prelude: bool,
540 glob_importers: RefCell<Vec<&'a Import<'a>>>,
541 globs: RefCell<Vec<&'a Import<'a>>>,
543 /// Used to memoize the traits in this module for faster searches through all traits in scope.
544 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
546 /// Span of the module itself. Used for error reporting.
552 type Module<'a> = &'a ModuleData<'a>;
554 impl<'a> ModuleData<'a> {
556 parent: Option<Module<'a>>,
560 no_implicit_prelude: bool,
562 let is_foreign = match kind {
563 ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
564 ModuleKind::Block(_) => false,
569 lazy_resolutions: Default::default(),
570 populate_on_access: Cell::new(is_foreign),
571 unexpanded_invocations: Default::default(),
573 glob_importers: RefCell::new(Vec::new()),
574 globs: RefCell::new(Vec::new()),
575 traits: RefCell::new(None),
581 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
583 R: AsMut<Resolver<'a>>,
584 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
586 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
587 if let Some(binding) = name_resolution.borrow().binding {
588 f(resolver, key.ident, key.ns, binding);
593 /// This modifies `self` in place. The traits will be stored in `self.traits`.
594 fn ensure_traits<R>(&'a self, resolver: &mut R)
596 R: AsMut<Resolver<'a>>,
598 let mut traits = self.traits.borrow_mut();
599 if traits.is_none() {
600 let mut collected_traits = Vec::new();
601 self.for_each_child(resolver, |_, name, ns, binding| {
605 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
606 collected_traits.push((name, binding))
609 *traits = Some(collected_traits.into_boxed_slice());
613 fn res(&self) -> Option<Res> {
615 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
620 // Public for rustdoc.
621 pub fn def_id(&self) -> DefId {
622 self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
625 fn opt_def_id(&self) -> Option<DefId> {
627 ModuleKind::Def(_, def_id, _) => Some(def_id),
632 // `self` resolves to the first module ancestor that `is_normal`.
633 fn is_normal(&self) -> bool {
634 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
637 fn is_trait(&self) -> bool {
638 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
641 fn nearest_item_scope(&'a self) -> Module<'a> {
643 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
644 self.parent.expect("enum or trait module without a parent")
650 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
651 /// This may be the crate root.
652 fn nearest_parent_mod(&self) -> DefId {
654 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
655 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
659 fn is_ancestor_of(&self, mut other: &Self) -> bool {
660 while !ptr::eq(self, other) {
661 if let Some(parent) = other.parent {
671 impl<'a> fmt::Debug for ModuleData<'a> {
672 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
673 write!(f, "{:?}", self.res())
677 /// Records a possibly-private value, type, or module definition.
678 #[derive(Clone, Debug)]
679 pub struct NameBinding<'a> {
680 kind: NameBindingKind<'a>,
681 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
682 expansion: LocalExpnId,
687 pub trait ToNameBinding<'a> {
688 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
691 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
692 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
697 #[derive(Clone, Debug)]
698 enum NameBindingKind<'a> {
699 Res(Res, /* is_macro_export */ bool),
701 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
704 impl<'a> NameBindingKind<'a> {
705 /// Is this a name binding of an import?
706 fn is_import(&self) -> bool {
707 matches!(*self, NameBindingKind::Import { .. })
711 struct PrivacyError<'a> {
713 binding: &'a NameBinding<'a>,
717 struct UseError<'a> {
718 err: DiagnosticBuilder<'a, ErrorGuaranteed>,
719 /// Candidates which user could `use` to access the missing type.
720 candidates: Vec<ImportSuggestion>,
721 /// The `DefId` of the module to place the use-statements in.
723 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
725 /// Extra free-form suggestion.
726 suggestion: Option<(Span, &'static str, String, Applicability)>,
729 #[derive(Clone, Copy, PartialEq, Debug)]
734 MacroRulesVsModularized,
742 fn descr(self) -> &'static str {
744 AmbiguityKind::Import => "multiple potential import sources",
745 AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute",
746 AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute",
747 AmbiguityKind::MacroRulesVsModularized => {
748 "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module"
750 AmbiguityKind::GlobVsOuter => {
751 "a conflict between a name from a glob import and an outer scope during import or macro resolution"
753 AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module",
754 AmbiguityKind::GlobVsExpanded => {
755 "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution"
757 AmbiguityKind::MoreExpandedVsOuter => {
758 "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution"
764 /// Miscellaneous bits of metadata for better ambiguity error reporting.
765 #[derive(Clone, Copy, PartialEq)]
766 enum AmbiguityErrorMisc {
773 struct AmbiguityError<'a> {
776 b1: &'a NameBinding<'a>,
777 b2: &'a NameBinding<'a>,
778 misc1: AmbiguityErrorMisc,
779 misc2: AmbiguityErrorMisc,
782 impl<'a> NameBinding<'a> {
783 fn module(&self) -> Option<Module<'a>> {
785 NameBindingKind::Module(module) => Some(module),
786 NameBindingKind::Import { binding, .. } => binding.module(),
791 fn res(&self) -> Res {
793 NameBindingKind::Res(res, _) => res,
794 NameBindingKind::Module(module) => module.res().unwrap(),
795 NameBindingKind::Import { binding, .. } => binding.res(),
799 fn is_ambiguity(&self) -> bool {
800 self.ambiguity.is_some()
802 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
807 fn is_possibly_imported_variant(&self) -> bool {
809 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
810 NameBindingKind::Res(
811 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
814 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
818 fn is_extern_crate(&self) -> bool {
820 NameBindingKind::Import {
821 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
824 NameBindingKind::Module(&ModuleData {
825 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
827 }) => def_id.index == CRATE_DEF_INDEX,
832 fn is_import(&self) -> bool {
833 matches!(self.kind, NameBindingKind::Import { .. })
836 fn is_glob_import(&self) -> bool {
838 NameBindingKind::Import { import, .. } => import.is_glob(),
843 fn is_importable(&self) -> bool {
846 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
850 fn macro_kind(&self) -> Option<MacroKind> {
851 self.res().macro_kind()
854 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
855 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
856 // Then this function returns `true` if `self` may emerge from a macro *after* that
857 // in some later round and screw up our previously found resolution.
858 // See more detailed explanation in
859 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
862 invoc_parent_expansion: LocalExpnId,
863 binding: &NameBinding<'_>,
865 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
866 // Expansions are partially ordered, so "may appear after" is an inversion of
867 // "certainly appears before or simultaneously" and includes unordered cases.
868 let self_parent_expansion = self.expansion;
869 let other_parent_expansion = binding.expansion;
870 let certainly_before_other_or_simultaneously =
871 other_parent_expansion.is_descendant_of(self_parent_expansion);
872 let certainly_before_invoc_or_simultaneously =
873 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
874 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
878 #[derive(Debug, Default, Clone)]
879 pub struct ExternPreludeEntry<'a> {
880 extern_crate_item: Option<&'a NameBinding<'a>>,
881 pub introduced_by_item: bool,
884 /// Used for better errors for E0773
885 enum BuiltinMacroState {
886 NotYetSeen(SyntaxExtensionKind),
891 resolutions: DeriveResolutions,
892 helper_attrs: Vec<(usize, Ident)>,
893 has_derive_copy: bool,
896 /// The main resolver class.
898 /// This is the visitor that walks the whole crate.
899 pub struct Resolver<'a> {
900 session: &'a Session,
902 definitions: Definitions,
904 graph_root: Module<'a>,
906 prelude: Option<Module<'a>>,
907 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
909 /// N.B., this is used only for better diagnostics, not name resolution itself.
910 has_self: FxHashSet<DefId>,
912 /// Names of fields of an item `DefId` accessible with dot syntax.
913 /// Used for hints during error reporting.
914 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
916 /// All imports known to succeed or fail.
917 determined_imports: Vec<&'a Import<'a>>,
919 /// All non-determined imports.
920 indeterminate_imports: Vec<&'a Import<'a>>,
922 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
923 /// We are resolving a last import segment during import validation.
924 last_import_segment: bool,
925 /// This binding should be ignored during in-module resolution, so that we don't get
926 /// "self-confirming" import resolutions during import validation.
927 unusable_binding: Option<&'a NameBinding<'a>>,
929 // Spans for local variables found during pattern resolution.
930 // Used for suggestions during error reporting.
931 pat_span_map: NodeMap<Span>,
933 /// Resolutions for nodes that have a single resolution.
934 partial_res_map: NodeMap<PartialRes>,
935 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
936 import_res_map: NodeMap<PerNS<Option<Res>>>,
937 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
938 label_res_map: NodeMap<NodeId>,
940 /// `CrateNum` resolutions of `extern crate` items.
941 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
942 reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
943 trait_map: NodeMap<Vec<TraitCandidate>>,
945 /// A map from nodes to anonymous modules.
946 /// Anonymous modules are pseudo-modules that are implicitly created around items
947 /// contained within blocks.
949 /// For example, if we have this:
957 /// There will be an anonymous module created around `g` with the ID of the
958 /// entry block for `f`.
959 block_map: NodeMap<Module<'a>>,
960 /// A fake module that contains no definition and no prelude. Used so that
961 /// some AST passes can generate identifiers that only resolve to local or
963 empty_module: Module<'a>,
964 module_map: FxHashMap<DefId, Module<'a>>,
965 binding_parent_modules: FxHashMap<Interned<'a, NameBinding<'a>>, Module<'a>>,
966 underscore_disambiguator: u32,
968 /// Maps glob imports to the names of items actually imported.
969 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
970 /// Visibilities in "lowered" form, for all entities that have them.
971 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
972 used_imports: FxHashSet<NodeId>,
973 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
974 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
976 /// Privacy errors are delayed until the end in order to deduplicate them.
977 privacy_errors: Vec<PrivacyError<'a>>,
978 /// Ambiguity errors are delayed for deduplication.
979 ambiguity_errors: Vec<AmbiguityError<'a>>,
980 /// `use` injections are delayed for better placement and deduplication.
981 use_injections: Vec<UseError<'a>>,
982 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
983 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
985 arenas: &'a ResolverArenas<'a>,
986 dummy_binding: &'a NameBinding<'a>,
988 crate_loader: CrateLoader<'a>,
989 macro_names: FxHashSet<Ident>,
990 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
991 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
992 /// the surface (`macro` items in libcore), but are actually attributes or derives.
993 builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
994 registered_attrs: FxHashSet<Ident>,
995 registered_tools: RegisteredTools,
996 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
997 all_macros: FxHashMap<Symbol, Res>,
998 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
999 dummy_ext_bang: Lrc<SyntaxExtension>,
1000 dummy_ext_derive: Lrc<SyntaxExtension>,
1001 non_macro_attr: Lrc<SyntaxExtension>,
1002 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
1003 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
1004 unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
1005 proc_macro_stubs: FxHashSet<LocalDefId>,
1006 /// Traces collected during macro resolution and validated when it's complete.
1007 single_segment_macro_resolutions:
1008 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
1009 multi_segment_macro_resolutions:
1010 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
1011 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
1012 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
1013 /// Derive macros cannot modify the item themselves and have to store the markers in the global
1014 /// context, so they attach the markers to derive container IDs using this resolver table.
1015 containers_deriving_copy: FxHashSet<LocalExpnId>,
1016 /// Parent scopes in which the macros were invoked.
1017 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
1018 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
1019 /// `macro_rules` scopes *produced* by expanding the macro invocations,
1020 /// include all the `macro_rules` items and other invocations generated by them.
1021 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
1022 /// Helper attributes that are in scope for the given expansion.
1023 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
1024 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
1025 /// with the given `ExpnId`.
1026 derive_data: FxHashMap<LocalExpnId, DeriveData>,
1028 /// Avoid duplicated errors for "name already defined".
1029 name_already_seen: FxHashMap<Symbol, Span>,
1031 potentially_unused_imports: Vec<&'a Import<'a>>,
1033 /// Table for mapping struct IDs into struct constructor IDs,
1034 /// it's not used during normal resolution, only for better error reporting.
1035 /// Also includes of list of each fields visibility
1036 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1038 /// Features enabled for this crate.
1039 active_features: FxHashSet<Symbol>,
1041 lint_buffer: LintBuffer,
1043 next_node_id: NodeId,
1045 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1046 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1048 /// Indices of unnamed struct or variant fields with unresolved attributes.
1049 placeholder_field_indices: FxHashMap<NodeId, usize>,
1050 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1051 /// we know what parent node that fragment should be attached to thanks to this table,
1052 /// and how the `impl Trait` fragments were introduced.
1053 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1055 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1056 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1057 /// FIXME: Replace with a more general AST map (together with some other fields).
1058 trait_impl_items: FxHashSet<LocalDefId>,
1060 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1061 /// Amount of lifetime parameters for each item in the crate.
1062 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1064 main_def: Option<MainDefinition>,
1065 trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
1066 /// A list of proc macro LocalDefIds, written out in the order in which
1067 /// they are declared in the static array generated by proc_macro_harness.
1068 proc_macros: Vec<NodeId>,
1069 confused_type_with_std_module: FxHashMap<Span, Span>,
1071 access_levels: AccessLevels,
1074 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1076 pub struct ResolverArenas<'a> {
1077 modules: TypedArena<ModuleData<'a>>,
1078 local_modules: RefCell<Vec<Module<'a>>>,
1079 imports: TypedArena<Import<'a>>,
1080 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1081 ast_paths: TypedArena<ast::Path>,
1082 dropless: DroplessArena,
1085 impl<'a> ResolverArenas<'a> {
1088 parent: Option<Module<'a>>,
1092 no_implicit_prelude: bool,
1093 module_map: &mut FxHashMap<DefId, Module<'a>>,
1096 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1097 let def_id = module.opt_def_id();
1098 if def_id.map_or(true, |def_id| def_id.is_local()) {
1099 self.local_modules.borrow_mut().push(module);
1101 if let Some(def_id) = def_id {
1102 module_map.insert(def_id, module);
1106 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1107 self.local_modules.borrow()
1109 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1110 self.dropless.alloc(name_binding)
1112 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1113 self.imports.alloc(import)
1115 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1116 self.name_resolutions.alloc(Default::default())
1118 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1119 Interned::new_unchecked(self.dropless.alloc(Cell::new(scope)))
1121 fn alloc_macro_rules_binding(
1123 binding: MacroRulesBinding<'a>,
1124 ) -> &'a MacroRulesBinding<'a> {
1125 self.dropless.alloc(binding)
1127 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1128 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1130 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1131 self.dropless.alloc_from_iter(spans)
1135 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1136 fn as_mut(&mut self) -> &mut Resolver<'a> {
1141 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1142 fn parent(self, id: DefId) -> Option<DefId> {
1143 match id.as_local() {
1144 Some(id) => self.definitions.def_key(id).parent,
1145 None => self.cstore().def_key(id).parent,
1147 .map(|index| DefId { index, ..id })
1151 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1152 /// the resolver is no longer needed as all the relevant information is inline.
1153 impl ResolverAstLowering for Resolver<'_> {
1154 fn def_key(&mut self, id: DefId) -> DefKey {
1155 if let Some(id) = id.as_local() {
1156 self.definitions().def_key(id)
1158 self.cstore().def_key(id)
1163 fn def_span(&self, id: LocalDefId) -> Span {
1164 self.definitions.def_span(id)
1167 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1168 if let Some(def_id) = def_id.as_local() {
1169 self.item_generics_num_lifetimes[&def_id]
1171 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1175 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1176 self.legacy_const_generic_args(expr)
1179 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1180 self.partial_res_map.get(&id).cloned()
1183 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1184 self.import_res_map.get(&id).cloned().unwrap_or_default()
1187 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1188 self.label_res_map.get(&id).cloned()
1191 fn definitions(&mut self) -> &mut Definitions {
1192 &mut self.definitions
1195 fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
1196 StableHashingContext::new(self.session, &self.definitions, self.crate_loader.cstore())
1199 fn lint_buffer(&mut self) -> &mut LintBuffer {
1200 &mut self.lint_buffer
1203 fn next_node_id(&mut self) -> NodeId {
1207 fn take_trait_map(&mut self, node: NodeId) -> Option<Vec<TraitCandidate>> {
1208 self.trait_map.remove(&node)
1211 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1212 self.node_id_to_def_id.get(&node).copied()
1215 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1216 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1219 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1220 match def_id.as_local() {
1221 Some(def_id) => self.definitions.def_path_hash(def_id),
1222 None => self.cstore().def_path_hash(def_id),
1226 /// Adds a definition with a parent definition.
1230 node_id: ast::NodeId,
1236 !self.node_id_to_def_id.contains_key(&node_id),
1237 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1240 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1243 // Find the next free disambiguator for this key.
1244 let next_disambiguator = &mut self.next_disambiguator;
1245 let next_disambiguator = |parent, data| {
1246 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1247 let disambiguator = *next_disamb;
1248 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1252 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1254 // Some things for which we allocate `LocalDefId`s don't correspond to
1255 // anything in the AST, so they don't have a `NodeId`. For these cases
1256 // we don't need a mapping from `NodeId` to `LocalDefId`.
1257 if node_id != ast::DUMMY_NODE_ID {
1258 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1259 self.node_id_to_def_id.insert(node_id, def_id);
1261 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1266 fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind {
1267 self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang)
1271 impl<'a> Resolver<'a> {
1273 session: &'a Session,
1276 metadata_loader: Box<MetadataLoaderDyn>,
1277 arenas: &'a ResolverArenas<'a>,
1279 let root_def_id = CRATE_DEF_ID.to_def_id();
1280 let mut module_map = FxHashMap::default();
1281 let graph_root = arenas.new_module(
1283 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1286 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1289 let empty_module = arenas.new_module(
1291 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1295 &mut FxHashMap::default(),
1298 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1299 let root = definitions.get_root_def();
1301 let mut visibilities = FxHashMap::default();
1302 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1304 let mut def_id_to_node_id = IndexVec::default();
1305 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1306 let mut node_id_to_def_id = FxHashMap::default();
1307 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1309 let mut invocation_parents = FxHashMap::default();
1310 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1312 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1316 .filter(|(_, entry)| entry.add_prelude)
1317 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1320 if !session.contains_name(&krate.attrs, sym::no_core) {
1321 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1322 if !session.contains_name(&krate.attrs, sym::no_std) {
1323 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1327 let (registered_attrs, registered_tools) =
1328 macros::registered_attrs_and_tools(session, &krate.attrs);
1330 let features = session.features_untracked();
1332 let mut resolver = Resolver {
1337 // The outermost module has def ID 0; this is not reflected in the
1343 has_self: FxHashSet::default(),
1344 field_names: FxHashMap::default(),
1346 determined_imports: Vec::new(),
1347 indeterminate_imports: Vec::new(),
1349 last_import_segment: false,
1350 unusable_binding: None,
1352 pat_span_map: Default::default(),
1353 partial_res_map: Default::default(),
1354 import_res_map: Default::default(),
1355 label_res_map: Default::default(),
1356 extern_crate_map: Default::default(),
1357 reexport_map: FxHashMap::default(),
1358 trait_map: NodeMap::default(),
1359 underscore_disambiguator: 0,
1362 block_map: Default::default(),
1363 binding_parent_modules: FxHashMap::default(),
1364 ast_transform_scopes: FxHashMap::default(),
1366 glob_map: Default::default(),
1368 used_imports: FxHashSet::default(),
1369 maybe_unused_trait_imports: Default::default(),
1370 maybe_unused_extern_crates: Vec::new(),
1372 privacy_errors: Vec::new(),
1373 ambiguity_errors: Vec::new(),
1374 use_injections: Vec::new(),
1375 macro_expanded_macro_export_errors: BTreeSet::new(),
1378 dummy_binding: arenas.alloc_name_binding(NameBinding {
1379 kind: NameBindingKind::Res(Res::Err, false),
1381 expansion: LocalExpnId::ROOT,
1383 vis: ty::Visibility::Public,
1386 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1387 macro_names: FxHashSet::default(),
1388 builtin_macros: Default::default(),
1389 builtin_macro_kinds: Default::default(),
1392 macro_use_prelude: FxHashMap::default(),
1393 all_macros: FxHashMap::default(),
1394 macro_map: FxHashMap::default(),
1395 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1396 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1397 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1398 invocation_parent_scopes: Default::default(),
1399 output_macro_rules_scopes: Default::default(),
1400 helper_attrs: Default::default(),
1401 derive_data: Default::default(),
1402 local_macro_def_scopes: FxHashMap::default(),
1403 name_already_seen: FxHashMap::default(),
1404 potentially_unused_imports: Vec::new(),
1405 struct_constructors: Default::default(),
1406 unused_macros: Default::default(),
1407 proc_macro_stubs: Default::default(),
1408 single_segment_macro_resolutions: Default::default(),
1409 multi_segment_macro_resolutions: Default::default(),
1410 builtin_attrs: Default::default(),
1411 containers_deriving_copy: Default::default(),
1412 active_features: features
1413 .declared_lib_features
1415 .map(|(feat, ..)| *feat)
1416 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1418 lint_buffer: LintBuffer::default(),
1419 next_node_id: CRATE_NODE_ID,
1422 placeholder_field_indices: Default::default(),
1424 next_disambiguator: Default::default(),
1425 trait_impl_items: Default::default(),
1426 legacy_const_generic_args: Default::default(),
1427 item_generics_num_lifetimes: Default::default(),
1428 main_def: Default::default(),
1429 trait_impls: Default::default(),
1430 proc_macros: Default::default(),
1431 confused_type_with_std_module: Default::default(),
1432 access_levels: Default::default(),
1435 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1436 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1443 parent: Option<Module<'a>>,
1447 no_implicit_prelude: bool,
1449 let module_map = &mut self.module_map;
1450 self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
1453 pub fn next_node_id(&mut self) -> NodeId {
1455 self.next_node_id.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
1456 mem::replace(&mut self.next_node_id, ast::NodeId::from_u32(next))
1459 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1460 &mut self.lint_buffer
1463 pub fn arenas() -> ResolverArenas<'a> {
1467 pub fn into_outputs(self) -> ResolverOutputs {
1468 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1469 let definitions = self.definitions;
1470 let visibilities = self.visibilities;
1471 let extern_crate_map = self.extern_crate_map;
1472 let reexport_map = self.reexport_map;
1473 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1474 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1475 let glob_map = self.glob_map;
1476 let main_def = self.main_def;
1477 let confused_type_with_std_module = self.confused_type_with_std_module;
1478 let access_levels = self.access_levels;
1481 cstore: Box::new(self.crate_loader.into_cstore()),
1487 maybe_unused_trait_imports,
1488 maybe_unused_extern_crates,
1489 extern_prelude: self
1492 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1495 trait_impls: self.trait_impls,
1497 confused_type_with_std_module,
1498 registered_tools: self.registered_tools,
1502 pub fn clone_outputs(&self) -> ResolverOutputs {
1503 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1505 definitions: self.definitions.clone(),
1506 access_levels: self.access_levels.clone(),
1507 cstore: Box::new(self.cstore().clone()),
1508 visibilities: self.visibilities.clone(),
1509 extern_crate_map: self.extern_crate_map.clone(),
1510 reexport_map: self.reexport_map.clone(),
1511 glob_map: self.glob_map.clone(),
1512 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1513 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1514 extern_prelude: self
1517 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1519 main_def: self.main_def,
1520 trait_impls: self.trait_impls.clone(),
1522 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1523 registered_tools: self.registered_tools.clone(),
1527 pub fn cstore(&self) -> &CStore {
1528 self.crate_loader.cstore()
1531 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1533 MacroKind::Bang => self.dummy_ext_bang.clone(),
1534 MacroKind::Derive => self.dummy_ext_derive.clone(),
1535 MacroKind::Attr => self.non_macro_attr.clone(),
1539 /// Runs the function on each namespace.
1540 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1546 fn is_builtin_macro(&mut self, res: Res) -> bool {
1547 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1550 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1552 match ctxt.outer_expn_data().macro_def_id {
1553 Some(def_id) => return def_id,
1554 None => ctxt.remove_mark(),
1559 /// Entry point to crate resolution.
1560 pub fn resolve_crate(&mut self, krate: &Crate) {
1561 self.session.time("resolve_crate", || {
1562 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1563 self.session.time("resolve_access_levels", || {
1564 AccessLevelsVisitor::compute_access_levels(self, krate)
1566 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1567 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1568 self.session.time("resolve_main", || self.resolve_main());
1569 self.session.time("resolve_check_unused", || self.check_unused(krate));
1570 self.session.time("resolve_report_errors", || self.report_errors(krate));
1571 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1575 pub fn traits_in_scope(
1577 current_trait: Option<Module<'a>>,
1578 parent_scope: &ParentScope<'a>,
1579 ctxt: SyntaxContext,
1580 assoc_item: Option<(Symbol, Namespace)>,
1581 ) -> Vec<TraitCandidate> {
1582 let mut found_traits = Vec::new();
1584 if let Some(module) = current_trait {
1585 if self.trait_may_have_item(Some(module), assoc_item) {
1586 let def_id = module.def_id();
1587 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1591 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1593 Scope::Module(module, _) => {
1594 this.traits_in_module(module, assoc_item, &mut found_traits);
1596 Scope::StdLibPrelude => {
1597 if let Some(module) = this.prelude {
1598 this.traits_in_module(module, assoc_item, &mut found_traits);
1601 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1602 _ => unreachable!(),
1610 fn traits_in_module(
1613 assoc_item: Option<(Symbol, Namespace)>,
1614 found_traits: &mut Vec<TraitCandidate>,
1616 module.ensure_traits(self);
1617 let traits = module.traits.borrow();
1618 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1619 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1620 let def_id = trait_binding.res().def_id();
1621 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1622 found_traits.push(TraitCandidate { def_id, import_ids });
1627 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1628 // associated item with the given name and namespace (if specified). This is a conservative
1629 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1630 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1631 // associated items.
1632 fn trait_may_have_item(
1634 trait_module: Option<Module<'a>>,
1635 assoc_item: Option<(Symbol, Namespace)>,
1637 match (trait_module, assoc_item) {
1638 (Some(trait_module), Some((name, ns))) => {
1639 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1640 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1641 assoc_ns == ns && assoc_ident.name == name
1648 fn find_transitive_imports(
1650 mut kind: &NameBindingKind<'_>,
1652 ) -> SmallVec<[LocalDefId; 1]> {
1653 let mut import_ids = smallvec![];
1654 while let NameBindingKind::Import { import, binding, .. } = kind {
1655 let id = self.local_def_id(import.id);
1656 self.maybe_unused_trait_imports.insert(id);
1657 self.add_to_glob_map(&import, trait_name);
1658 import_ids.push(id);
1659 kind = &binding.kind;
1664 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1665 let ident = ident.normalize_to_macros_2_0();
1666 let disambiguator = if ident.name == kw::Underscore {
1667 self.underscore_disambiguator += 1;
1668 self.underscore_disambiguator
1672 BindingKey { ident, ns, disambiguator }
1675 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1676 if module.populate_on_access.get() {
1677 module.populate_on_access.set(false);
1678 self.build_reduced_graph_external(module);
1680 &module.lazy_resolutions
1687 ) -> &'a RefCell<NameResolution<'a>> {
1689 .resolutions(module)
1692 .or_insert_with(|| self.arenas.alloc_name_resolution())
1698 used_binding: &'a NameBinding<'a>,
1699 is_lexical_scope: bool,
1701 if let Some((b2, kind)) = used_binding.ambiguity {
1702 self.ambiguity_errors.push(AmbiguityError {
1707 misc1: AmbiguityErrorMisc::None,
1708 misc2: AmbiguityErrorMisc::None,
1711 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1712 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1713 // but not introduce it, as used if they are accessed from lexical scope.
1714 if is_lexical_scope {
1715 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1716 if let Some(crate_item) = entry.extern_crate_item {
1717 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1724 import.used.set(true);
1725 self.used_imports.insert(import.id);
1726 self.add_to_glob_map(&import, ident);
1727 self.record_use(ident, binding, false);
1732 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1733 if import.is_glob() {
1734 let def_id = self.local_def_id(import.id);
1735 self.glob_map.entry(def_id).or_default().insert(ident.name);
1739 /// A generic scope visitor.
1740 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1741 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1744 scope_set: ScopeSet<'a>,
1745 parent_scope: &ParentScope<'a>,
1746 ctxt: SyntaxContext,
1747 mut visitor: impl FnMut(
1750 /*use_prelude*/ bool,
1754 // General principles:
1755 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1756 // built into the language or standard library. This way we can add new names into the
1757 // language or standard library without breaking user code.
1758 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1759 // Places to search (in order of decreasing priority):
1761 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1762 // (open set, not controlled).
1763 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1764 // (open, not controlled).
1765 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1766 // 4. Tool modules (closed, controlled right now, but not in the future).
1767 // 5. Standard library prelude (de-facto closed, controlled).
1768 // 6. Language prelude (closed, controlled).
1770 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1771 // (open set, not controlled).
1772 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1773 // (open, not controlled).
1774 // 3. Standard library prelude (de-facto closed, controlled).
1776 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1777 // are currently reported as errors. They should be higher in priority than preludes
1778 // and probably even names in modules according to the "general principles" above. They
1779 // also should be subject to restricted shadowing because are effectively produced by
1780 // derives (you need to resolve the derive first to add helpers into scope), but they
1781 // should be available before the derive is expanded for compatibility.
1782 // It's mess in general, so we are being conservative for now.
1783 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1784 // priority than prelude macros, but create ambiguities with macros in modules.
1785 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1786 // (open, not controlled). Have higher priority than prelude macros, but create
1787 // ambiguities with `macro_rules`.
1788 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1789 // 4a. User-defined prelude from macro-use
1790 // (open, the open part is from macro expansions, not controlled).
1791 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1792 // 4c. Standard library prelude (de-facto closed, controlled).
1793 // 6. Language prelude: builtin attributes (closed, controlled).
1795 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1796 let (ns, macro_kind, is_absolute_path) = match scope_set {
1797 ScopeSet::All(ns, _) => (ns, None, false),
1798 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1799 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1800 ScopeSet::Late(ns, ..) => (ns, None, false),
1802 let module = match scope_set {
1803 // Start with the specified module.
1804 ScopeSet::Late(_, module, _) => module,
1805 // Jump out of trait or enum modules, they do not act as scopes.
1806 _ => parent_scope.module.nearest_item_scope(),
1808 let mut scope = match ns {
1809 _ if is_absolute_path => Scope::CrateRoot,
1810 TypeNS | ValueNS => Scope::Module(module, None),
1811 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1813 let mut ctxt = ctxt.normalize_to_macros_2_0();
1814 let mut use_prelude = !module.no_implicit_prelude;
1817 let visit = match scope {
1818 // Derive helpers are not in scope when resolving derives in the same container.
1819 Scope::DeriveHelpers(expn_id) => {
1820 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1822 Scope::DeriveHelpersCompat => true,
1823 Scope::MacroRules(macro_rules_scope) => {
1824 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1825 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1826 // As another consequence of this optimization visitors never observe invocation
1827 // scopes for macros that were already expanded.
1828 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1829 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1830 macro_rules_scope.set(next_scope.get());
1837 Scope::CrateRoot => true,
1838 Scope::Module(..) => true,
1839 Scope::RegisteredAttrs => use_prelude,
1840 Scope::MacroUsePrelude => use_prelude || rust_2015,
1841 Scope::BuiltinAttrs => true,
1842 Scope::ExternPrelude => use_prelude || is_absolute_path,
1843 Scope::ToolPrelude => use_prelude,
1844 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1845 Scope::BuiltinTypes => true,
1849 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1850 return break_result;
1854 scope = match scope {
1855 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1856 Scope::DeriveHelpers(expn_id) => {
1857 // Derive helpers are not visible to code generated by bang or derive macros.
1858 let expn_data = expn_id.expn_data();
1859 match expn_data.kind {
1861 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1862 Scope::DeriveHelpersCompat
1864 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1867 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1868 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1869 MacroRulesScope::Binding(binding) => {
1870 Scope::MacroRules(binding.parent_macro_rules_scope)
1872 MacroRulesScope::Invocation(invoc_id) => {
1873 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1875 MacroRulesScope::Empty => Scope::Module(module, None),
1877 Scope::CrateRoot => match ns {
1879 ctxt.adjust(ExpnId::root());
1880 Scope::ExternPrelude
1882 ValueNS | MacroNS => break,
1884 Scope::Module(module, prev_lint_id) => {
1885 use_prelude = !module.no_implicit_prelude;
1886 let derive_fallback_lint_id = match scope_set {
1887 ScopeSet::Late(.., lint_id) => lint_id,
1890 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1891 Some((parent_module, lint_id)) => {
1892 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1895 ctxt.adjust(ExpnId::root());
1897 TypeNS => Scope::ExternPrelude,
1898 ValueNS => Scope::StdLibPrelude,
1899 MacroNS => Scope::RegisteredAttrs,
1904 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1905 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1906 Scope::BuiltinAttrs => break, // nowhere else to search
1907 Scope::ExternPrelude if is_absolute_path => break,
1908 Scope::ExternPrelude => Scope::ToolPrelude,
1909 Scope::ToolPrelude => Scope::StdLibPrelude,
1910 Scope::StdLibPrelude => match ns {
1911 TypeNS => Scope::BuiltinTypes,
1912 ValueNS => break, // nowhere else to search
1913 MacroNS => Scope::BuiltinAttrs,
1915 Scope::BuiltinTypes => break, // nowhere else to search
1922 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1923 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1924 /// `ident` in the first scope that defines it (or None if no scopes define it).
1926 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1927 /// the items are defined in the block. For example,
1930 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1933 /// g(); // This resolves to the local variable `g` since it shadows the item.
1937 /// Invariant: This must only be called during main resolution, not during
1938 /// import resolution.
1939 fn resolve_ident_in_lexical_scope(
1943 parent_scope: &ParentScope<'a>,
1944 record_used_id: Option<NodeId>,
1947 ) -> Option<LexicalScopeBinding<'a>> {
1948 assert!(ns == TypeNS || ns == ValueNS);
1949 let orig_ident = ident;
1950 if ident.name == kw::Empty {
1951 return Some(LexicalScopeBinding::Res(Res::Err));
1953 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1954 // FIXME(jseyfried) improve `Self` hygiene
1955 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1956 (empty_span, empty_span)
1957 } else if ns == TypeNS {
1958 let normalized_span = ident.span.normalize_to_macros_2_0();
1959 (normalized_span, normalized_span)
1961 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1963 ident.span = general_span;
1964 let normalized_ident = Ident { span: normalized_span, ..ident };
1966 // Walk backwards up the ribs in scope.
1967 let record_used = record_used_id.is_some();
1968 let mut module = self.graph_root;
1969 for i in (0..ribs.len()).rev() {
1970 debug!("walk rib\n{:?}", ribs[i].bindings);
1971 // Use the rib kind to determine whether we are resolving parameters
1972 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1973 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1974 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1976 // The ident resolves to a type parameter or local variable.
1977 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1983 *original_rib_ident_def,
1988 module = match ribs[i].kind {
1989 ModuleRibKind(module) => module,
1990 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1991 // If an invocation of this macro created `ident`, give up on `ident`
1992 // and switch to `ident`'s source from the macro definition.
1993 ident.span.remove_mark();
2000 ModuleKind::Block(..) => {} // We can see through blocks
2004 let item = self.resolve_ident_in_module_unadjusted(
2005 ModuleOrUniformRoot::Module(module),
2012 if let Ok(binding) = item {
2013 // The ident resolves to an item.
2014 return Some(LexicalScopeBinding::Item(binding));
2017 self.early_resolve_ident_in_lexical_scope(
2019 ScopeSet::Late(ns, module, record_used_id),
2026 .map(LexicalScopeBinding::Item)
2029 fn hygienic_lexical_parent(
2032 ctxt: &mut SyntaxContext,
2033 derive_fallback_lint_id: Option<NodeId>,
2034 ) -> Option<(Module<'a>, Option<NodeId>)> {
2035 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2036 return Some((self.expn_def_scope(ctxt.remove_mark()), None));
2039 if let ModuleKind::Block(..) = module.kind {
2040 return Some((module.parent.unwrap().nearest_item_scope(), None));
2043 // We need to support the next case under a deprecation warning
2046 // ---- begin: this comes from a proc macro derive
2047 // mod implementation_details {
2048 // // Note that `MyStruct` is not in scope here.
2049 // impl SomeTrait for MyStruct { ... }
2053 // So we have to fall back to the module's parent during lexical resolution in this case.
2054 if derive_fallback_lint_id.is_some() {
2055 if let Some(parent) = module.parent {
2056 // Inner module is inside the macro, parent module is outside of the macro.
2057 if module.expansion != parent.expansion
2058 && module.expansion.is_descendant_of(parent.expansion)
2060 // The macro is a proc macro derive
2061 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2062 let ext = self.get_macro_by_def_id(def_id);
2063 if ext.builtin_name.is_none()
2064 && ext.macro_kind() == MacroKind::Derive
2065 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2067 return Some((parent, derive_fallback_lint_id));
2077 fn resolve_ident_in_module(
2079 module: ModuleOrUniformRoot<'a>,
2082 parent_scope: &ParentScope<'a>,
2085 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2086 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2087 .map_err(|(determinacy, _)| determinacy)
2090 fn resolve_ident_in_module_ext(
2092 module: ModuleOrUniformRoot<'a>,
2095 parent_scope: &ParentScope<'a>,
2098 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2099 let tmp_parent_scope;
2100 let mut adjusted_parent_scope = parent_scope;
2102 ModuleOrUniformRoot::Module(m) => {
2103 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2105 ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
2106 adjusted_parent_scope = &tmp_parent_scope;
2109 ModuleOrUniformRoot::ExternPrelude => {
2110 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2112 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2116 self.resolve_ident_in_module_unadjusted_ext(
2120 adjusted_parent_scope,
2127 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2128 debug!("resolve_crate_root({:?})", ident);
2129 let mut ctxt = ident.span.ctxt();
2130 let mark = if ident.name == kw::DollarCrate {
2131 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2132 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2133 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2134 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2135 // definitions actually produced by `macro` and `macro` definitions produced by
2136 // `macro_rules!`, but at least such configurations are not stable yet.
2137 ctxt = ctxt.normalize_to_macro_rules();
2139 "resolve_crate_root: marks={:?}",
2140 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2142 let mut iter = ctxt.marks().into_iter().rev().peekable();
2143 let mut result = None;
2144 // Find the last opaque mark from the end if it exists.
2145 while let Some(&(mark, transparency)) = iter.peek() {
2146 if transparency == Transparency::Opaque {
2147 result = Some(mark);
2154 "resolve_crate_root: found opaque mark {:?} {:?}",
2156 result.map(|r| r.expn_data())
2158 // Then find the last semi-transparent mark from the end if it exists.
2159 for (mark, transparency) in iter {
2160 if transparency == Transparency::SemiTransparent {
2161 result = Some(mark);
2167 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2169 result.map(|r| r.expn_data())
2173 debug!("resolve_crate_root: not DollarCrate");
2174 ctxt = ctxt.normalize_to_macros_2_0();
2175 ctxt.adjust(ExpnId::root())
2177 let module = match mark {
2178 Some(def) => self.expn_def_scope(def),
2181 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2184 return self.graph_root;
2187 let module = self.expect_module(
2188 module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(),
2191 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2200 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2201 let mut module = self.expect_module(module.nearest_parent_mod());
2202 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2203 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
2204 module = self.expect_module(parent.nearest_parent_mod());
2212 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2213 parent_scope: &ParentScope<'a>,
2216 crate_lint: CrateLint,
2217 ) -> PathResult<'a> {
2218 self.resolve_path_with_ribs(
2229 fn resolve_path_with_ribs(
2232 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2233 parent_scope: &ParentScope<'a>,
2236 crate_lint: CrateLint,
2237 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2238 ) -> PathResult<'a> {
2239 let mut module = None;
2240 let mut allow_super = true;
2241 let mut second_binding = None;
2244 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2245 path_span={:?}, crate_lint={:?})",
2246 path, opt_ns, record_used, path_span, crate_lint,
2249 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2250 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2251 let record_segment_res = |this: &mut Self, res| {
2253 if let Some(id) = id {
2254 if !this.partial_res_map.contains_key(&id) {
2255 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2256 this.record_partial_res(id, PartialRes::new(res));
2262 let is_last = i == path.len() - 1;
2263 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2264 let name = ident.name;
2266 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2269 if allow_super && name == kw::Super {
2270 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2271 let self_module = match i {
2272 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2274 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2278 if let Some(self_module) = self_module {
2279 if let Some(parent) = self_module.parent {
2280 module = Some(ModuleOrUniformRoot::Module(
2281 self.resolve_self(&mut ctxt, parent),
2286 let msg = "there are too many leading `super` keywords".to_string();
2287 return PathResult::Failed {
2291 is_error_from_last_segment: false,
2295 if name == kw::SelfLower {
2296 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2297 module = Some(ModuleOrUniformRoot::Module(
2298 self.resolve_self(&mut ctxt, parent_scope.module),
2302 if name == kw::PathRoot && ident.span.rust_2018() {
2303 module = Some(ModuleOrUniformRoot::ExternPrelude);
2306 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2307 // `::a::b` from 2015 macro on 2018 global edition
2308 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2311 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2312 // `::a::b`, `crate::a::b` or `$crate::a::b`
2313 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2319 // Report special messages for path segment keywords in wrong positions.
2320 if ident.is_path_segment_keyword() && i != 0 {
2321 let name_str = if name == kw::PathRoot {
2322 "crate root".to_string()
2324 format!("`{}`", name)
2326 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2327 format!("global paths cannot start with {}", name_str)
2329 format!("{} in paths can only be used in start position", name_str)
2331 return PathResult::Failed {
2335 is_error_from_last_segment: false,
2339 enum FindBindingResult<'a> {
2340 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2341 PathResult(PathResult<'a>),
2343 let find_binding_in_ns = |this: &mut Self, ns| {
2344 let binding = if let Some(module) = module {
2345 this.resolve_ident_in_module(
2353 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2354 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2355 this.early_resolve_ident_in_lexical_scope(
2364 let record_used_id = if record_used {
2365 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2369 match this.resolve_ident_in_lexical_scope(
2377 // we found a locally-imported or available item/module
2378 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2379 // we found a local variable or type param
2380 Some(LexicalScopeBinding::Res(res))
2381 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2383 record_segment_res(this, res);
2384 return FindBindingResult::PathResult(PathResult::NonModule(
2385 PartialRes::with_unresolved_segments(res, path.len() - 1),
2388 _ => Err(Determinacy::determined(record_used)),
2391 FindBindingResult::Binding(binding)
2393 let binding = match find_binding_in_ns(self, ns) {
2394 FindBindingResult::PathResult(x) => return x,
2395 FindBindingResult::Binding(binding) => binding,
2400 second_binding = Some(binding);
2402 let res = binding.res();
2403 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2404 if let Some(next_module) = binding.module() {
2405 module = Some(ModuleOrUniformRoot::Module(next_module));
2406 record_segment_res(self, res);
2407 } else if res == Res::ToolMod && i + 1 != path.len() {
2408 if binding.is_import() {
2412 "cannot use a tool module through an import",
2414 .span_note(binding.span, "the tool module imported here")
2417 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2418 return PathResult::NonModule(PartialRes::new(res));
2419 } else if res == Res::Err {
2420 return PathResult::NonModule(PartialRes::new(Res::Err));
2421 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2422 self.lint_if_path_starts_with_module(
2428 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2433 let label = format!(
2434 "`{}` is {} {}, not a module",
2440 return PathResult::Failed {
2444 is_error_from_last_segment: is_last,
2448 Err(Undetermined) => return PathResult::Indeterminate,
2449 Err(Determined) => {
2450 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2451 if opt_ns.is_some() && !module.is_normal() {
2452 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2453 module.res().unwrap(),
2458 let module_res = match module {
2459 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2462 let (label, suggestion) = if module_res == self.graph_root.res() {
2463 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2464 // Don't look up import candidates if this is a speculative resolve
2465 let mut candidates = if record_used {
2466 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2470 candidates.sort_by_cached_key(|c| {
2471 (c.path.segments.len(), pprust::path_to_string(&c.path))
2473 if let Some(candidate) = candidates.get(0) {
2475 String::from("unresolved import"),
2477 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2478 String::from("a similar path exists"),
2479 Applicability::MaybeIncorrect,
2482 } else if self.session.edition() == Edition::Edition2015 {
2483 (format!("maybe a missing crate `{}`?", ident), None)
2485 (format!("could not find `{}` in the crate root", ident), None)
2493 .map_or(false, |c| c.is_ascii_uppercase())
2495 // Check whether the name refers to an item in the value namespace.
2496 let suggestion = if ribs.is_some() {
2497 let match_span = match self.resolve_ident_in_lexical_scope(
2503 &ribs.unwrap()[ValueNS],
2505 // Name matches a local variable. For example:
2508 // let Foo: &str = "";
2509 // println!("{}", Foo::Bar); // Name refers to local
2510 // // variable `Foo`.
2513 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2514 Some(*self.pat_span_map.get(&id).unwrap())
2517 // Name matches item from a local name binding
2518 // created by `use` declaration. For example:
2520 // pub Foo: &str = "";
2524 // println!("{}", Foo::Bar); // Name refers to local
2525 // // binding `Foo`.
2528 Some(LexicalScopeBinding::Item(name_binding)) => {
2529 Some(name_binding.span)
2534 if let Some(span) = match_span {
2536 vec![(span, String::from(""))],
2537 format!("`{}` is defined here, but is not a type", ident),
2538 Applicability::MaybeIncorrect,
2547 (format!("use of undeclared type `{}`", ident), suggestion)
2550 format!("use of undeclared crate or module `{}`", ident),
2551 if ident.name == sym::alloc {
2555 "add `extern crate alloc` to use the `alloc` crate",
2557 Applicability::MaybeIncorrect,
2560 self.find_similarly_named_module_or_crate(
2562 &parent_scope.module,
2566 vec![(ident.span, sugg.to_string())],
2568 "there is a crate or module with a similar name",
2570 Applicability::MaybeIncorrect,
2577 let parent = path[i - 1].ident.name;
2578 let parent = match parent {
2579 // ::foo is mounted at the crate root for 2015, and is the extern
2580 // prelude for 2018+
2581 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2582 "the list of imported crates".to_owned()
2584 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2586 format!("`{}`", parent)
2590 let mut msg = format!("could not find `{}` in {}", ident, parent);
2591 if ns == TypeNS || ns == ValueNS {
2592 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2593 if let FindBindingResult::Binding(Ok(binding)) =
2594 find_binding_in_ns(self, ns_to_try)
2596 let mut found = |what| {
2598 "expected {}, found {} `{}` in {}",
2605 if binding.module().is_some() {
2608 match binding.res() {
2609 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2610 _ => found(ns_to_try.descr()),
2617 return PathResult::Failed {
2621 is_error_from_last_segment: is_last,
2627 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2629 PathResult::Module(match module {
2630 Some(module) => module,
2631 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2632 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2636 fn lint_if_path_starts_with_module(
2638 crate_lint: CrateLint,
2641 second_binding: Option<&NameBinding<'_>>,
2643 let (diag_id, diag_span) = match crate_lint {
2644 CrateLint::No => return,
2645 CrateLint::SimplePath(id) => (id, path_span),
2646 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2647 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2650 let first_name = match path.get(0) {
2651 // In the 2018 edition this lint is a hard error, so nothing to do
2652 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2656 // We're only interested in `use` paths which should start with
2657 // `{{root}}` currently.
2658 if first_name != kw::PathRoot {
2663 // If this import looks like `crate::...` it's already good
2664 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2665 // Otherwise go below to see if it's an extern crate
2667 // If the path has length one (and it's `PathRoot` most likely)
2668 // then we don't know whether we're gonna be importing a crate or an
2669 // item in our crate. Defer this lint to elsewhere
2673 // If the first element of our path was actually resolved to an
2674 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2675 // warning, this looks all good!
2676 if let Some(binding) = second_binding {
2677 if let NameBindingKind::Import { import, .. } = binding.kind {
2678 // Careful: we still want to rewrite paths from renamed extern crates.
2679 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2685 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2686 self.lint_buffer.buffer_lint_with_diagnostic(
2687 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2690 "absolute paths must start with `self`, `super`, \
2691 `crate`, or an external crate name in the 2018 edition",
2696 // Validate a local resolution (from ribs).
2697 fn validate_res_from_ribs(
2704 original_rib_ident_def: Ident,
2705 all_ribs: &[Rib<'a>],
2707 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2708 debug!("validate_res_from_ribs({:?})", res);
2709 let ribs = &all_ribs[rib_index + 1..];
2711 // An invalid forward use of a generic parameter from a previous default.
2712 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2714 let res_error = if rib_ident.name == kw::SelfUpper {
2715 ResolutionError::SelfInGenericParamDefault
2717 ResolutionError::ForwardDeclaredGenericParam
2719 self.report_error(span, res_error);
2721 assert_eq!(res, Res::Err);
2727 use ResolutionError::*;
2728 let mut res_err = None;
2733 | ClosureOrAsyncRibKind
2735 | MacroDefinition(..)
2736 | ForwardGenericParamBanRibKind => {
2737 // Nothing to do. Continue.
2739 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2740 // This was an attempt to access an upvar inside a
2741 // named function item. This is not allowed, so we
2744 // We don't immediately trigger a resolve error, because
2745 // we want certain other resolution errors (namely those
2746 // emitted for `ConstantItemRibKind` below) to take
2748 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2751 ConstantItemRibKind(_, item) => {
2752 // Still doesn't deal with upvars
2754 let (span, resolution_error) =
2755 if let Some((ident, constant_item_kind)) = item {
2756 let kind_str = match constant_item_kind {
2757 ConstantItemKind::Const => "const",
2758 ConstantItemKind::Static => "static",
2762 AttemptToUseNonConstantValueInConstant(
2763 ident, "let", kind_str,
2769 AttemptToUseNonConstantValueInConstant(
2770 original_rib_ident_def,
2776 self.report_error(span, resolution_error);
2780 ConstParamTyRibKind => {
2782 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2788 if let Some(res_err) = res_err {
2789 self.report_error(span, res_err);
2793 Res::Def(DefKind::TyParam, _) | Res::SelfTy { .. } => {
2795 let has_generic_params: HasGenericParams = match rib.kind {
2797 | ClosureOrAsyncRibKind
2800 | MacroDefinition(..)
2801 | ForwardGenericParamBanRibKind => {
2802 // Nothing to do. Continue.
2806 ConstantItemRibKind(trivial, _) => {
2807 let features = self.session.features_untracked();
2808 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2809 if !(trivial || features.generic_const_exprs) {
2810 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2811 // we can't easily tell if it's generic at this stage, so we instead remember
2812 // this and then enforce the self type to be concrete later on.
2813 if let Res::SelfTy { trait_, alias_to: Some((def, _)) } = res {
2814 res = Res::SelfTy { trait_, alias_to: Some((def, true)) }
2819 ResolutionError::ParamInNonTrivialAnonConst {
2820 name: rib_ident.name,
2826 self.session.delay_span_bug(span, CG_BUG_STR);
2834 // This was an attempt to use a type parameter outside its scope.
2835 ItemRibKind(has_generic_params) => has_generic_params,
2836 FnItemRibKind => HasGenericParams::Yes,
2837 ConstParamTyRibKind => {
2841 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2851 ResolutionError::GenericParamsFromOuterFunction(
2860 Res::Def(DefKind::ConstParam, _) => {
2861 let mut ribs = ribs.iter().peekable();
2862 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2863 // When declaring const parameters inside function signatures, the first rib
2864 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2865 // (spuriously) conflicting with the const param.
2870 let has_generic_params = match rib.kind {
2872 | ClosureOrAsyncRibKind
2875 | MacroDefinition(..)
2876 | ForwardGenericParamBanRibKind => continue,
2878 ConstantItemRibKind(trivial, _) => {
2879 let features = self.session.features_untracked();
2880 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2881 if !(trivial || features.generic_const_exprs) {
2885 ResolutionError::ParamInNonTrivialAnonConst {
2886 name: rib_ident.name,
2892 self.session.delay_span_bug(span, CG_BUG_STR);
2899 ItemRibKind(has_generic_params) => has_generic_params,
2900 FnItemRibKind => HasGenericParams::Yes,
2901 ConstParamTyRibKind => {
2905 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2912 // This was an attempt to use a const parameter outside its scope.
2916 ResolutionError::GenericParamsFromOuterFunction(
2930 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2931 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2932 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2933 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2937 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2938 debug!("(recording pat) recording {:?} for {:?}", node, span);
2939 self.pat_span_map.insert(node, span);
2942 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2943 vis.is_accessible_from(module.nearest_parent_mod(), self)
2946 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2947 if let Some(old_module) =
2948 self.binding_parent_modules.insert(Interned::new_unchecked(binding), module)
2950 if !ptr::eq(module, old_module) {
2951 span_bug!(binding.span, "parent module is reset for binding");
2956 fn disambiguate_macro_rules_vs_modularized(
2958 macro_rules: &'a NameBinding<'a>,
2959 modularized: &'a NameBinding<'a>,
2961 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2962 // is disambiguated to mitigate regressions from macro modularization.
2963 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2965 self.binding_parent_modules.get(&Interned::new_unchecked(macro_rules)),
2966 self.binding_parent_modules.get(&Interned::new_unchecked(modularized)),
2968 (Some(macro_rules), Some(modularized)) => {
2969 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
2970 && modularized.is_ancestor_of(macro_rules)
2976 fn report_errors(&mut self, krate: &Crate) {
2977 self.report_with_use_injections(krate);
2979 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2980 let msg = "macro-expanded `macro_export` macros from the current crate \
2981 cannot be referred to by absolute paths";
2982 self.lint_buffer.buffer_lint_with_diagnostic(
2983 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2987 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2991 for ambiguity_error in &self.ambiguity_errors {
2992 self.report_ambiguity_error(ambiguity_error);
2995 let mut reported_spans = FxHashSet::default();
2996 for error in &self.privacy_errors {
2997 if reported_spans.insert(error.dedup_span) {
2998 self.report_privacy_error(error);
3003 fn report_with_use_injections(&mut self, krate: &Crate) {
3004 for UseError { mut err, candidates, def_id, instead, suggestion } in
3005 self.use_injections.drain(..)
3007 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
3008 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
3012 if !candidates.is_empty() {
3013 diagnostics::show_candidates(
3022 } else if let Some((span, msg, sugg, appl)) = suggestion {
3023 err.span_suggestion(span, msg, sugg, appl);
3029 fn report_conflict<'b>(
3034 new_binding: &NameBinding<'b>,
3035 old_binding: &NameBinding<'b>,
3037 // Error on the second of two conflicting names
3038 if old_binding.span.lo() > new_binding.span.lo() {
3039 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3042 let container = match parent.kind {
3043 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
3044 ModuleKind::Block(..) => "block",
3047 let old_noun = match old_binding.is_import() {
3049 false => "definition",
3052 let new_participle = match new_binding.is_import() {
3058 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3060 if let Some(s) = self.name_already_seen.get(&name) {
3066 let old_kind = match (ns, old_binding.module()) {
3067 (ValueNS, _) => "value",
3068 (MacroNS, _) => "macro",
3069 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3070 (TypeNS, Some(module)) if module.is_normal() => "module",
3071 (TypeNS, Some(module)) if module.is_trait() => "trait",
3072 (TypeNS, _) => "type",
3075 let msg = format!("the name `{}` is defined multiple times", name);
3077 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3078 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3079 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3080 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3081 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3083 _ => match (old_binding.is_import(), new_binding.is_import()) {
3084 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3085 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3086 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3091 "`{}` must be defined only once in the {} namespace of this {}",
3097 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3099 self.session.source_map().guess_head_span(old_binding.span),
3100 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3103 // See https://github.com/rust-lang/rust/issues/32354
3104 use NameBindingKind::Import;
3105 let import = match (&new_binding.kind, &old_binding.kind) {
3106 // If there are two imports where one or both have attributes then prefer removing the
3107 // import without attributes.
3108 (Import { import: new, .. }, Import { import: old, .. })
3110 !new_binding.span.is_dummy()
3111 && !old_binding.span.is_dummy()
3112 && (new.has_attributes || old.has_attributes)
3115 if old.has_attributes {
3116 Some((new, new_binding.span, true))
3118 Some((old, old_binding.span, true))
3121 // Otherwise prioritize the new binding.
3122 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3123 Some((import, new_binding.span, other.is_import()))
3125 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3126 Some((import, old_binding.span, other.is_import()))
3131 // Check if the target of the use for both bindings is the same.
3132 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3133 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3135 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3136 // Only suggest removing an import if both bindings are to the same def, if both spans
3137 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3138 // been introduced by an item.
3139 let should_remove_import = duplicate
3141 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3144 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3145 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3147 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3148 // Simple case - remove the entire import. Due to the above match arm, this can
3149 // only be a single use so just remove it entirely.
3150 err.tool_only_span_suggestion(
3151 import.use_span_with_attributes,
3152 "remove unnecessary import",
3154 Applicability::MaybeIncorrect,
3157 Some((import, span, _)) => {
3158 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3164 self.name_already_seen.insert(name, span);
3167 /// This function adds a suggestion to change the binding name of a new import that conflicts
3168 /// with an existing import.
3170 /// ```text,ignore (diagnostic)
3171 /// help: you can use `as` to change the binding name of the import
3173 /// LL | use foo::bar as other_bar;
3174 /// | ^^^^^^^^^^^^^^^^^^^^^
3176 fn add_suggestion_for_rename_of_use(
3178 err: &mut Diagnostic,
3180 import: &Import<'_>,
3183 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3184 format!("Other{}", name)
3186 format!("other_{}", name)
3189 let mut suggestion = None;
3191 ImportKind::Single { type_ns_only: true, .. } => {
3192 suggestion = Some(format!("self as {}", suggested_name))
3194 ImportKind::Single { source, .. } => {
3196 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3198 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3199 if pos <= snippet.len() {
3200 suggestion = Some(format!(
3204 if snippet.ends_with(';') { ";" } else { "" }
3210 ImportKind::ExternCrate { source, target } => {
3211 suggestion = Some(format!(
3212 "extern crate {} as {};",
3213 source.unwrap_or(target.name),
3217 _ => unreachable!(),
3220 let rename_msg = "you can use `as` to change the binding name of the import";
3221 if let Some(suggestion) = suggestion {
3222 err.span_suggestion(
3226 Applicability::MaybeIncorrect,
3229 err.span_label(binding_span, rename_msg);
3233 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3234 /// nested. In the following example, this function will be invoked to remove the `a` binding
3235 /// in the second use statement:
3237 /// ```ignore (diagnostic)
3238 /// use issue_52891::a;
3239 /// use issue_52891::{d, a, e};
3242 /// The following suggestion will be added:
3244 /// ```ignore (diagnostic)
3245 /// use issue_52891::{d, a, e};
3246 /// ^-- help: remove unnecessary import
3249 /// If the nested use contains only one import then the suggestion will remove the entire
3252 /// It is expected that the provided import is nested - this isn't checked by the
3253 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3254 /// as characters expected by span manipulations won't be present.
3255 fn add_suggestion_for_duplicate_nested_use(
3257 err: &mut Diagnostic,
3258 import: &Import<'_>,
3261 assert!(import.is_nested());
3262 let message = "remove unnecessary import";
3264 // Two examples will be used to illustrate the span manipulations we're doing:
3266 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3267 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3268 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3269 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3271 let (found_closing_brace, span) =
3272 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3274 // If there was a closing brace then identify the span to remove any trailing commas from
3275 // previous imports.
3276 if found_closing_brace {
3277 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3278 err.tool_only_span_suggestion(
3282 Applicability::MaybeIncorrect,
3285 // Remove the entire line if we cannot extend the span back, this indicates an
3286 // `issue_52891::{self}` case.
3287 err.span_suggestion(
3288 import.use_span_with_attributes,
3291 Applicability::MaybeIncorrect,
3298 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3301 fn extern_prelude_get(
3305 ) -> Option<&'a NameBinding<'a>> {
3306 if ident.is_path_segment_keyword() {
3307 // Make sure `self`, `super` etc produce an error when passed to here.
3310 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3311 if let Some(binding) = entry.extern_crate_item {
3312 if !speculative && entry.introduced_by_item {
3313 self.record_use(ident, binding, false);
3317 let crate_id = if !speculative {
3318 let Some(crate_id) =
3319 self.crate_loader.process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
3322 self.crate_loader.maybe_process_path_extern(ident.name)?
3324 let crate_root = self.expect_module(crate_id.as_def_id());
3326 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3327 .to_name_binding(self.arenas),
3333 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3334 /// isn't something that can be returned because it can't be made to live that long,
3335 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3336 /// just that an error occurred.
3337 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3338 pub fn resolve_str_path_error(
3344 ) -> Result<(ast::Path, Res), ()> {
3345 let path = if path_str.starts_with("::") {
3348 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3349 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3350 .map(|i| self.new_ast_path_segment(i))
3359 .map(Ident::from_str)
3360 .map(|i| self.new_ast_path_segment(i))
3365 let module = self.expect_module(module_id);
3366 let parent_scope = &ParentScope::module(module, self);
3367 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3371 // Resolve a path passed from rustdoc or HIR lowering.
3372 fn resolve_ast_path(
3376 parent_scope: &ParentScope<'a>,
3377 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3378 match self.resolve_path(
3379 &Segment::from_path(path),
3386 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3387 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3388 Ok(path_res.base_res())
3390 PathResult::NonModule(..) => Err((
3392 ResolutionError::FailedToResolve {
3393 label: String::from("type-relative paths are not supported in this context"),
3397 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3398 PathResult::Failed { span, label, suggestion, .. } => {
3399 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3404 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3405 let mut seg = ast::PathSegment::from_ident(ident);
3406 seg.id = self.next_node_id();
3411 pub fn graph_root(&self) -> Module<'a> {
3416 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3421 /// For local modules returns only reexports, for external modules returns all children.
3422 pub fn module_children_or_reexports(&self, def_id: DefId) -> Vec<ModChild> {
3423 if let Some(def_id) = def_id.as_local() {
3424 self.reexport_map.get(&def_id).cloned().unwrap_or_default()
3426 self.cstore().module_children_untracked(def_id, self.session)
3430 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3432 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3433 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3436 /// Checks if an expression refers to a function marked with
3437 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3438 /// from the attribute.
3439 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3440 if let ExprKind::Path(None, path) = &expr.kind {
3441 // Don't perform legacy const generics rewriting if the path already
3442 // has generic arguments.
3443 if path.segments.last().unwrap().args.is_some() {
3447 let partial_res = self.partial_res_map.get(&expr.id)?;
3448 if partial_res.unresolved_segments() != 0 {
3452 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3453 // We only support cross-crate argument rewriting. Uses
3454 // within the same crate should be updated to use the new
3455 // const generics style.
3456 if def_id.is_local() {
3460 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3466 .item_attrs_untracked(def_id, self.session)
3467 .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3468 let mut ret = Vec::new();
3469 for meta in attr.meta_item_list()? {
3470 match meta.literal()?.kind {
3471 LitKind::Int(a, _) => ret.push(a as usize),
3472 _ => panic!("invalid arg index"),
3475 // Cache the lookup to avoid parsing attributes for an iterm multiple times.
3476 self.legacy_const_generic_args.insert(def_id, Some(ret.clone()));
3483 fn resolve_main(&mut self) {
3484 let module = self.graph_root;
3485 let ident = Ident::with_dummy_span(sym::main);
3486 let parent_scope = &ParentScope::module(module, self);
3488 let Ok(name_binding) = self.resolve_ident_in_module(
3489 ModuleOrUniformRoot::Module(module),
3499 let res = name_binding.res();
3500 let is_import = name_binding.is_import();
3501 let span = name_binding.span;
3502 if let Res::Def(DefKind::Fn, _) = res {
3503 self.record_use(ident, name_binding, false);
3505 self.main_def = Some(MainDefinition { res, is_import, span });
3509 fn names_to_string(names: &[Symbol]) -> String {
3510 let mut result = String::new();
3511 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3513 result.push_str("::");
3515 if Ident::with_dummy_span(*name).is_raw_guess() {
3516 result.push_str("r#");
3518 result.push_str(name.as_str());
3523 fn path_names_to_string(path: &Path) -> String {
3524 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3527 /// A somewhat inefficient routine to obtain the name of a module.
3528 fn module_to_string(module: Module<'_>) -> Option<String> {
3529 let mut names = Vec::new();
3531 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3532 if let ModuleKind::Def(.., name) = module.kind {
3533 if let Some(parent) = module.parent {
3535 collect_mod(names, parent);
3538 names.push(Symbol::intern("<opaque>"));
3539 collect_mod(names, module.parent.unwrap());
3542 collect_mod(&mut names, module);
3544 if names.is_empty() {
3548 Some(names_to_string(&names))
3551 #[derive(Copy, Clone, Debug)]
3553 /// Do not issue the lint.
3556 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3557 /// In this case, we can take the span of that path.
3560 /// This lint comes from a `use` statement. In this case, what we
3561 /// care about really is the *root* `use` statement; e.g., if we
3562 /// have nested things like `use a::{b, c}`, we care about the
3564 UsePath { root_id: NodeId, root_span: Span },
3566 /// This is the "trait item" from a fully qualified path. For example,
3567 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3568 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3569 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3573 fn node_id(&self) -> Option<NodeId> {
3575 CrateLint::No => None,
3576 CrateLint::SimplePath(id)
3577 | CrateLint::UsePath { root_id: id, .. }
3578 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3583 pub fn provide(providers: &mut Providers) {
3584 late::lifetimes::provide(providers);