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)]
25 pub use rustc_hir::def::{Namespace, PerNS};
29 use rustc_arena::{DroplessArena, TypedArena};
30 use rustc_ast::node_id::NodeMap;
31 use rustc_ast::ptr::P;
32 use rustc_ast::visit::{self, Visitor};
33 use rustc_ast::{self as ast, NodeId};
34 use rustc_ast::{Crate, CRATE_NODE_ID};
35 use rustc_ast::{Expr, ExprKind, LitKind};
36 use rustc_ast::{ItemKind, ModKind, Path};
37 use rustc_ast_lowering::ResolverAstLowering;
38 use rustc_ast_pretty::pprust;
39 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
40 use rustc_data_structures::ptr_key::PtrKey;
41 use rustc_data_structures::sync::Lrc;
42 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
43 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
44 use rustc_hir::def::Namespace::*;
45 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
46 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
47 use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
48 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
49 use rustc_hir::TraitCandidate;
50 use rustc_index::vec::IndexVec;
51 use rustc_metadata::creader::{CStore, CrateLoader};
52 use rustc_middle::hir::exports::ExportMap;
53 use rustc_middle::span_bug;
54 use rustc_middle::ty::query::Providers;
55 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
56 use rustc_query_system::ich::StableHashingContext;
57 use rustc_session::cstore::{CrateStore, MetadataLoaderDyn};
58 use rustc_session::lint;
59 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
60 use rustc_session::Session;
61 use rustc_span::edition::Edition;
62 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
63 use rustc_span::source_map::Spanned;
64 use rustc_span::symbol::{kw, sym, Ident, Symbol};
65 use rustc_span::{Span, DUMMY_SP};
67 use smallvec::{smallvec, SmallVec};
68 use std::cell::{Cell, RefCell};
69 use std::collections::{BTreeMap, BTreeSet};
70 use std::ops::ControlFlow;
71 use std::{cmp, fmt, iter, mem, ptr};
74 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
75 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
76 use imports::{Import, ImportKind, ImportResolver, NameResolution};
77 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
78 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
80 type Res = def::Res<NodeId>;
82 mod build_reduced_graph;
95 #[derive(Copy, Clone, PartialEq, Debug)]
96 pub enum Determinacy {
102 fn determined(determined: bool) -> Determinacy {
103 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
107 /// A specific scope in which a name can be looked up.
108 /// This enum is currently used only for early resolution (imports and macros),
109 /// but not for late resolution yet.
110 #[derive(Clone, Copy)]
112 DeriveHelpers(LocalExpnId),
114 MacroRules(MacroRulesScopeRef<'a>),
116 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
117 // lint if it should be reported.
118 Module(Module<'a>, Option<NodeId>),
128 /// Names from different contexts may want to visit different subsets of all specific scopes
129 /// with different restrictions when looking up the resolution.
130 /// This enum is currently used only for early resolution (imports and macros),
131 /// but not for late resolution yet.
132 #[derive(Clone, Copy)]
134 /// All scopes with the given namespace.
135 All(Namespace, /*is_import*/ bool),
136 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
137 AbsolutePath(Namespace),
138 /// All scopes with macro namespace and the given macro kind restriction.
140 /// All scopes with the given namespace, used for partially performing late resolution.
141 /// The node id enables lints and is used for reporting them.
142 Late(Namespace, Module<'a>, Option<NodeId>),
145 /// Everything you need to know about a name's location to resolve it.
146 /// Serves as a starting point for the scope visitor.
147 /// This struct is currently used only for early resolution (imports and macros),
148 /// but not for late resolution yet.
149 #[derive(Clone, Copy, Debug)]
150 pub struct ParentScope<'a> {
152 expansion: LocalExpnId,
153 macro_rules: MacroRulesScopeRef<'a>,
154 derives: &'a [ast::Path],
157 impl<'a> ParentScope<'a> {
158 /// Creates a parent scope with the passed argument used as the module scope component,
159 /// and other scope components set to default empty values.
160 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
163 expansion: LocalExpnId::ROOT,
164 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
170 #[derive(Copy, Debug, Clone)]
171 enum ImplTraitContext {
173 Universal(LocalDefId),
177 struct BindingError {
179 origin: BTreeSet<Span>,
180 target: BTreeSet<Span>,
184 impl PartialOrd for BindingError {
185 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
186 Some(self.cmp(other))
190 impl PartialEq for BindingError {
191 fn eq(&self, other: &BindingError) -> bool {
192 self.name == other.name
196 impl Ord for BindingError {
197 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
198 self.name.cmp(&other.name)
202 enum ResolutionError<'a> {
203 /// Error E0401: can't use type or const parameters from outer function.
204 GenericParamsFromOuterFunction(Res, HasGenericParams),
205 /// Error E0403: the name is already used for a type or const parameter in this generic
207 NameAlreadyUsedInParameterList(Symbol, Span),
208 /// Error E0407: method is not a member of trait.
209 MethodNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
210 /// Error E0437: type is not a member of trait.
211 TypeNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
212 /// Error E0438: const is not a member of trait.
213 ConstNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
214 /// Error E0408: variable `{}` is not bound in all patterns.
215 VariableNotBoundInPattern(&'a BindingError),
216 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
217 VariableBoundWithDifferentMode(Symbol, Span),
218 /// Error E0415: identifier is bound more than once in this parameter list.
219 IdentifierBoundMoreThanOnceInParameterList(Symbol),
220 /// Error E0416: identifier is bound more than once in the same pattern.
221 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
222 /// Error E0426: use of undeclared label.
223 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
224 /// Error E0429: `self` imports are only allowed within a `{ }` list.
225 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
226 /// Error E0430: `self` import can only appear once in the list.
227 SelfImportCanOnlyAppearOnceInTheList,
228 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
229 SelfImportOnlyInImportListWithNonEmptyPrefix,
230 /// Error E0433: failed to resolve.
231 FailedToResolve { label: String, suggestion: Option<Suggestion> },
232 /// Error E0434: can't capture dynamic environment in a fn item.
233 CannotCaptureDynamicEnvironmentInFnItem,
234 /// Error E0435: attempt to use a non-constant value in a constant.
235 AttemptToUseNonConstantValueInConstant(
237 /* suggestion */ &'static str,
238 /* current */ &'static str,
240 /// Error E0530: `X` bindings cannot shadow `Y`s.
241 BindingShadowsSomethingUnacceptable {
242 shadowing_binding_descr: &'static str,
244 participle: &'static str,
245 article: &'static str,
246 shadowed_binding_descr: &'static str,
247 shadowed_binding_span: Span,
249 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
250 ForwardDeclaredGenericParam,
251 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
252 ParamInTyOfConstParam(Symbol),
253 /// generic parameters must not be used inside const evaluations.
255 /// This error is only emitted when using `min_const_generics`.
256 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
257 /// Error E0735: generic parameters with a default cannot use `Self`
258 SelfInGenericParamDefault,
259 /// Error E0767: use of unreachable label
260 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
263 enum VisResolutionError<'a> {
264 Relative2018(Span, &'a ast::Path),
266 FailedToResolve(Span, String, Option<Suggestion>),
267 ExpectedFound(Span, String, Res),
272 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
273 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
274 #[derive(Clone, Copy, Debug)]
278 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
279 /// nonsensical suggestions.
280 has_generic_args: bool,
284 fn from_path(path: &Path) -> Vec<Segment> {
285 path.segments.iter().map(|s| s.into()).collect()
288 fn from_ident(ident: Ident) -> Segment {
289 Segment { ident, id: None, has_generic_args: false }
292 fn names_to_string(segments: &[Segment]) -> String {
293 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
297 impl<'a> From<&'a ast::PathSegment> for Segment {
298 fn from(seg: &'a ast::PathSegment) -> Segment {
299 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
303 struct UsePlacementFinder {
304 target_module: NodeId,
309 impl UsePlacementFinder {
310 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
311 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
312 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
313 visit::walk_crate(&mut finder, krate);
315 (finder.span, finder.found_use)
318 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
319 if self.span.is_some() {
320 return ControlFlow::Break(());
322 if node_id != self.target_module {
323 return ControlFlow::Continue(());
325 // find a use statement
328 ItemKind::Use(..) => {
329 // don't suggest placing a use before the prelude
330 // import or other generated ones
331 if !item.span.from_expansion() {
332 self.span = Some(item.span.shrink_to_lo());
333 self.found_use = true;
334 return ControlFlow::Break(());
337 // don't place use before extern crate
338 ItemKind::ExternCrate(_) => {}
339 // but place them before the first other item
341 if self.span.map_or(true, |span| item.span < span)
342 && !item.span.from_expansion()
344 self.span = Some(item.span.shrink_to_lo());
345 // don't insert between attributes and an item
346 // find the first attribute on the item
347 // FIXME: This is broken for active attributes.
348 for attr in &item.attrs {
349 if !attr.span.is_dummy()
350 && self.span.map_or(true, |span| attr.span < span)
352 self.span = Some(attr.span.shrink_to_lo());
359 ControlFlow::Continue(())
363 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
364 fn visit_item(&mut self, item: &'tcx ast::Item) {
365 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
366 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
370 visit::walk_item(self, item);
374 /// An intermediate resolution result.
376 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
377 /// items are visible in their whole block, while `Res`es only from the place they are defined
380 enum LexicalScopeBinding<'a> {
381 Item(&'a NameBinding<'a>),
385 impl<'a> LexicalScopeBinding<'a> {
386 fn res(self) -> Res {
388 LexicalScopeBinding::Item(binding) => binding.res(),
389 LexicalScopeBinding::Res(res) => res,
394 #[derive(Copy, Clone, Debug)]
395 enum ModuleOrUniformRoot<'a> {
399 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
400 CrateRootAndExternPrelude,
402 /// Virtual module that denotes resolution in extern prelude.
403 /// Used for paths starting with `::` on 2018 edition.
406 /// Virtual module that denotes resolution in current scope.
407 /// Used only for resolving single-segment imports. The reason it exists is that import paths
408 /// are always split into two parts, the first of which should be some kind of module.
412 impl ModuleOrUniformRoot<'_> {
413 fn same_def(lhs: Self, rhs: Self) -> bool {
415 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
419 ModuleOrUniformRoot::CrateRootAndExternPrelude,
420 ModuleOrUniformRoot::CrateRootAndExternPrelude,
422 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
423 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
429 #[derive(Clone, Debug)]
430 enum PathResult<'a> {
431 Module(ModuleOrUniformRoot<'a>),
432 NonModule(PartialRes),
437 suggestion: Option<Suggestion>,
438 is_error_from_last_segment: bool,
444 /// An anonymous module; e.g., just a block.
449 /// { // This is an anonymous module
450 /// f(); // This resolves to (2) as we are inside the block.
453 /// f(); // Resolves to (1)
457 /// Any module with a name.
461 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
462 /// or the crate root (which is conceptually a top-level module).
463 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
464 /// * A trait or an enum (it implicitly contains associated types, methods and variant
466 Def(DefKind, DefId, Symbol),
470 /// Get name of the module.
471 pub fn name(&self) -> Option<Symbol> {
473 ModuleKind::Block(..) => None,
474 ModuleKind::Def(.., name) => Some(*name),
479 /// A key that identifies a binding in a given `Module`.
481 /// Multiple bindings in the same module can have the same key (in a valid
482 /// program) if all but one of them come from glob imports.
483 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
485 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
489 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
490 /// `_` in the expanded AST that introduced this binding.
494 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
496 /// One node in the tree of modules.
498 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
501 /// * crate root (aka, top-level anonymous module)
504 /// * curly-braced block with statements
506 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
507 pub struct ModuleData<'a> {
508 /// The direct parent module (it may not be a `mod`, however).
509 parent: Option<Module<'a>>,
510 /// What kind of module this is, because this may not be a `mod`.
513 /// Mapping between names and their (possibly in-progress) resolutions in this module.
514 /// Resolutions in modules from other crates are not populated until accessed.
515 lazy_resolutions: Resolutions<'a>,
516 /// True if this is a module from other crate that needs to be populated on access.
517 populate_on_access: Cell<bool>,
519 /// Macro invocations that can expand into items in this module.
520 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
522 /// Whether `#[no_implicit_prelude]` is active.
523 no_implicit_prelude: bool,
525 glob_importers: RefCell<Vec<&'a Import<'a>>>,
526 globs: RefCell<Vec<&'a Import<'a>>>,
528 /// Used to memoize the traits in this module for faster searches through all traits in scope.
529 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
531 /// Span of the module itself. Used for error reporting.
537 type Module<'a> = &'a ModuleData<'a>;
539 impl<'a> ModuleData<'a> {
541 parent: Option<Module<'a>>,
545 no_implicit_prelude: bool,
547 let is_foreign = match kind {
548 ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
549 ModuleKind::Block(_) => false,
554 lazy_resolutions: Default::default(),
555 populate_on_access: Cell::new(is_foreign),
556 unexpanded_invocations: Default::default(),
558 glob_importers: RefCell::new(Vec::new()),
559 globs: RefCell::new(Vec::new()),
560 traits: RefCell::new(None),
566 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
568 R: AsMut<Resolver<'a>>,
569 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
571 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
572 if let Some(binding) = name_resolution.borrow().binding {
573 f(resolver, key.ident, key.ns, binding);
578 /// This modifies `self` in place. The traits will be stored in `self.traits`.
579 fn ensure_traits<R>(&'a self, resolver: &mut R)
581 R: AsMut<Resolver<'a>>,
583 let mut traits = self.traits.borrow_mut();
584 if traits.is_none() {
585 let mut collected_traits = Vec::new();
586 self.for_each_child(resolver, |_, name, ns, binding| {
590 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
591 collected_traits.push((name, binding))
594 *traits = Some(collected_traits.into_boxed_slice());
598 fn res(&self) -> Option<Res> {
600 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
605 fn def_id(&self) -> DefId {
606 self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
609 fn opt_def_id(&self) -> Option<DefId> {
611 ModuleKind::Def(_, def_id, _) => Some(def_id),
616 // `self` resolves to the first module ancestor that `is_normal`.
617 fn is_normal(&self) -> bool {
618 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
621 fn is_trait(&self) -> bool {
622 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
625 fn nearest_item_scope(&'a self) -> Module<'a> {
627 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
628 self.parent.expect("enum or trait module without a parent")
634 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
635 /// This may be the crate root.
636 fn nearest_parent_mod(&self) -> DefId {
638 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
639 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
643 fn is_ancestor_of(&self, mut other: &Self) -> bool {
644 while !ptr::eq(self, other) {
645 if let Some(parent) = other.parent {
655 impl<'a> fmt::Debug for ModuleData<'a> {
656 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
657 write!(f, "{:?}", self.res())
661 /// Records a possibly-private value, type, or module definition.
662 #[derive(Clone, Debug)]
663 pub struct NameBinding<'a> {
664 kind: NameBindingKind<'a>,
665 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
666 expansion: LocalExpnId,
671 pub trait ToNameBinding<'a> {
672 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
675 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
676 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
681 #[derive(Clone, Debug)]
682 enum NameBindingKind<'a> {
683 Res(Res, /* is_macro_export */ bool),
685 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
688 impl<'a> NameBindingKind<'a> {
689 /// Is this a name binding of an import?
690 fn is_import(&self) -> bool {
691 matches!(*self, NameBindingKind::Import { .. })
695 struct PrivacyError<'a> {
697 binding: &'a NameBinding<'a>,
701 struct UseError<'a> {
702 err: DiagnosticBuilder<'a>,
703 /// Candidates which user could `use` to access the missing type.
704 candidates: Vec<ImportSuggestion>,
705 /// The `DefId` of the module to place the use-statements in.
707 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
709 /// Extra free-form suggestion.
710 suggestion: Option<(Span, &'static str, String, Applicability)>,
713 #[derive(Clone, Copy, PartialEq, Debug)]
718 MacroRulesVsModularized,
726 fn descr(self) -> &'static str {
728 AmbiguityKind::Import => "multiple potential import sources",
729 AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute",
730 AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute",
731 AmbiguityKind::MacroRulesVsModularized => {
732 "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module"
734 AmbiguityKind::GlobVsOuter => {
735 "a conflict between a name from a glob import and an outer scope during import or macro resolution"
737 AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module",
738 AmbiguityKind::GlobVsExpanded => {
739 "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution"
741 AmbiguityKind::MoreExpandedVsOuter => {
742 "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution"
748 /// Miscellaneous bits of metadata for better ambiguity error reporting.
749 #[derive(Clone, Copy, PartialEq)]
750 enum AmbiguityErrorMisc {
757 struct AmbiguityError<'a> {
760 b1: &'a NameBinding<'a>,
761 b2: &'a NameBinding<'a>,
762 misc1: AmbiguityErrorMisc,
763 misc2: AmbiguityErrorMisc,
766 impl<'a> NameBinding<'a> {
767 fn module(&self) -> Option<Module<'a>> {
769 NameBindingKind::Module(module) => Some(module),
770 NameBindingKind::Import { binding, .. } => binding.module(),
775 fn res(&self) -> Res {
777 NameBindingKind::Res(res, _) => res,
778 NameBindingKind::Module(module) => module.res().unwrap(),
779 NameBindingKind::Import { binding, .. } => binding.res(),
783 fn is_ambiguity(&self) -> bool {
784 self.ambiguity.is_some()
786 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
791 fn is_possibly_imported_variant(&self) -> bool {
793 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
794 NameBindingKind::Res(
795 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
798 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
802 fn is_extern_crate(&self) -> bool {
804 NameBindingKind::Import {
805 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
808 NameBindingKind::Module(&ModuleData {
809 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
811 }) => def_id.index == CRATE_DEF_INDEX,
816 fn is_import(&self) -> bool {
817 matches!(self.kind, NameBindingKind::Import { .. })
820 fn is_glob_import(&self) -> bool {
822 NameBindingKind::Import { import, .. } => import.is_glob(),
827 fn is_importable(&self) -> bool {
830 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
834 fn is_macro_def(&self) -> bool {
835 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
838 fn macro_kind(&self) -> Option<MacroKind> {
839 self.res().macro_kind()
842 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
843 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
844 // Then this function returns `true` if `self` may emerge from a macro *after* that
845 // in some later round and screw up our previously found resolution.
846 // See more detailed explanation in
847 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
850 invoc_parent_expansion: LocalExpnId,
851 binding: &NameBinding<'_>,
853 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
854 // Expansions are partially ordered, so "may appear after" is an inversion of
855 // "certainly appears before or simultaneously" and includes unordered cases.
856 let self_parent_expansion = self.expansion;
857 let other_parent_expansion = binding.expansion;
858 let certainly_before_other_or_simultaneously =
859 other_parent_expansion.is_descendant_of(self_parent_expansion);
860 let certainly_before_invoc_or_simultaneously =
861 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
862 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
866 #[derive(Debug, Default, Clone)]
867 pub struct ExternPreludeEntry<'a> {
868 extern_crate_item: Option<&'a NameBinding<'a>>,
869 pub introduced_by_item: bool,
872 /// Used for better errors for E0773
873 enum BuiltinMacroState {
874 NotYetSeen(SyntaxExtensionKind),
879 resolutions: DeriveResolutions,
880 helper_attrs: Vec<(usize, Ident)>,
881 has_derive_copy: bool,
884 /// The main resolver class.
886 /// This is the visitor that walks the whole crate.
887 pub struct Resolver<'a> {
888 session: &'a Session,
890 definitions: Definitions,
892 graph_root: Module<'a>,
894 prelude: Option<Module<'a>>,
895 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
897 /// N.B., this is used only for better diagnostics, not name resolution itself.
898 has_self: FxHashSet<DefId>,
900 /// Names of fields of an item `DefId` accessible with dot syntax.
901 /// Used for hints during error reporting.
902 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
904 /// All imports known to succeed or fail.
905 determined_imports: Vec<&'a Import<'a>>,
907 /// All non-determined imports.
908 indeterminate_imports: Vec<&'a Import<'a>>,
910 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
911 /// We are resolving a last import segment during import validation.
912 last_import_segment: bool,
913 /// This binding should be ignored during in-module resolution, so that we don't get
914 /// "self-confirming" import resolutions during import validation.
915 unusable_binding: Option<&'a NameBinding<'a>>,
917 // Spans for local variables found during pattern resolution.
918 // Used for suggestions during error reporting.
919 pat_span_map: NodeMap<Span>,
921 /// Resolutions for nodes that have a single resolution.
922 partial_res_map: NodeMap<PartialRes>,
923 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
924 import_res_map: NodeMap<PerNS<Option<Res>>>,
925 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
926 label_res_map: NodeMap<NodeId>,
928 /// `CrateNum` resolutions of `extern crate` items.
929 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
930 export_map: ExportMap,
931 trait_map: NodeMap<Vec<TraitCandidate>>,
933 /// A map from nodes to anonymous modules.
934 /// Anonymous modules are pseudo-modules that are implicitly created around items
935 /// contained within blocks.
937 /// For example, if we have this:
945 /// There will be an anonymous module created around `g` with the ID of the
946 /// entry block for `f`.
947 block_map: NodeMap<Module<'a>>,
948 /// A fake module that contains no definition and no prelude. Used so that
949 /// some AST passes can generate identifiers that only resolve to local or
951 empty_module: Module<'a>,
952 module_map: FxHashMap<DefId, Module<'a>>,
953 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
954 underscore_disambiguator: u32,
956 /// Maps glob imports to the names of items actually imported.
957 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
958 /// Visibilities in "lowered" form, for all entities that have them.
959 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
960 used_imports: FxHashSet<NodeId>,
961 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
962 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
964 /// Privacy errors are delayed until the end in order to deduplicate them.
965 privacy_errors: Vec<PrivacyError<'a>>,
966 /// Ambiguity errors are delayed for deduplication.
967 ambiguity_errors: Vec<AmbiguityError<'a>>,
968 /// `use` injections are delayed for better placement and deduplication.
969 use_injections: Vec<UseError<'a>>,
970 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
971 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
973 arenas: &'a ResolverArenas<'a>,
974 dummy_binding: &'a NameBinding<'a>,
976 crate_loader: CrateLoader<'a>,
977 macro_names: FxHashSet<Ident>,
978 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
979 registered_attrs: FxHashSet<Ident>,
980 registered_tools: FxHashSet<Ident>,
981 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
982 all_macros: FxHashMap<Symbol, Res>,
983 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
984 dummy_ext_bang: Lrc<SyntaxExtension>,
985 dummy_ext_derive: Lrc<SyntaxExtension>,
986 non_macro_attr: Lrc<SyntaxExtension>,
987 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
988 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
989 unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
990 proc_macro_stubs: FxHashSet<LocalDefId>,
991 /// Traces collected during macro resolution and validated when it's complete.
992 single_segment_macro_resolutions:
993 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
994 multi_segment_macro_resolutions:
995 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
996 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
997 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
998 /// Derive macros cannot modify the item themselves and have to store the markers in the global
999 /// context, so they attach the markers to derive container IDs using this resolver table.
1000 containers_deriving_copy: FxHashSet<LocalExpnId>,
1001 /// Parent scopes in which the macros were invoked.
1002 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
1003 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
1004 /// `macro_rules` scopes *produced* by expanding the macro invocations,
1005 /// include all the `macro_rules` items and other invocations generated by them.
1006 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
1007 /// Helper attributes that are in scope for the given expansion.
1008 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
1009 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
1010 /// with the given `ExpnId`.
1011 derive_data: FxHashMap<LocalExpnId, DeriveData>,
1013 /// Avoid duplicated errors for "name already defined".
1014 name_already_seen: FxHashMap<Symbol, Span>,
1016 potentially_unused_imports: Vec<&'a Import<'a>>,
1018 /// Table for mapping struct IDs into struct constructor IDs,
1019 /// it's not used during normal resolution, only for better error reporting.
1020 /// Also includes of list of each fields visibility
1021 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1023 /// Features enabled for this crate.
1024 active_features: FxHashSet<Symbol>,
1026 lint_buffer: LintBuffer,
1028 next_node_id: NodeId,
1030 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1031 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1033 /// Indices of unnamed struct or variant fields with unresolved attributes.
1034 placeholder_field_indices: FxHashMap<NodeId, usize>,
1035 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1036 /// we know what parent node that fragment should be attached to thanks to this table,
1037 /// and how the `impl Trait` fragments were introduced.
1038 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1040 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1041 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1042 /// FIXME: Replace with a more general AST map (together with some other fields).
1043 trait_impl_items: FxHashSet<LocalDefId>,
1045 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1046 /// Amount of lifetime parameters for each item in the crate.
1047 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1049 main_def: Option<MainDefinition>,
1050 trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
1051 /// A list of proc macro LocalDefIds, written out in the order in which
1052 /// they are declared in the static array generated by proc_macro_harness.
1053 proc_macros: Vec<NodeId>,
1054 confused_type_with_std_module: FxHashMap<Span, Span>,
1057 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1059 pub struct ResolverArenas<'a> {
1060 modules: TypedArena<ModuleData<'a>>,
1061 local_modules: RefCell<Vec<Module<'a>>>,
1062 imports: TypedArena<Import<'a>>,
1063 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1064 ast_paths: TypedArena<ast::Path>,
1065 dropless: DroplessArena,
1068 impl<'a> ResolverArenas<'a> {
1071 parent: Option<Module<'a>>,
1075 no_implicit_prelude: bool,
1076 module_map: &mut FxHashMap<DefId, Module<'a>>,
1079 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1080 let def_id = module.opt_def_id();
1081 if def_id.map_or(true, |def_id| def_id.is_local()) {
1082 self.local_modules.borrow_mut().push(module);
1084 if let Some(def_id) = def_id {
1085 module_map.insert(def_id, module);
1089 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1090 self.local_modules.borrow()
1092 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1093 self.dropless.alloc(name_binding)
1095 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1096 self.imports.alloc(import)
1098 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1099 self.name_resolutions.alloc(Default::default())
1101 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1102 PtrKey(self.dropless.alloc(Cell::new(scope)))
1104 fn alloc_macro_rules_binding(
1106 binding: MacroRulesBinding<'a>,
1107 ) -> &'a MacroRulesBinding<'a> {
1108 self.dropless.alloc(binding)
1110 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1111 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1113 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1114 self.dropless.alloc_from_iter(spans)
1118 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1119 fn as_mut(&mut self) -> &mut Resolver<'a> {
1124 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1125 fn parent(self, id: DefId) -> Option<DefId> {
1126 match id.as_local() {
1127 Some(id) => self.definitions.def_key(id).parent,
1128 None => self.cstore().def_key(id).parent,
1130 .map(|index| DefId { index, ..id })
1134 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1135 /// the resolver is no longer needed as all the relevant information is inline.
1136 impl ResolverAstLowering for Resolver<'_> {
1137 fn def_key(&mut self, id: DefId) -> DefKey {
1138 if let Some(id) = id.as_local() {
1139 self.definitions().def_key(id)
1141 self.cstore().def_key(id)
1146 fn def_span(&self, id: LocalDefId) -> Span {
1147 self.definitions.def_span(id)
1150 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1151 if let Some(def_id) = def_id.as_local() {
1152 self.item_generics_num_lifetimes[&def_id]
1154 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1158 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1159 self.legacy_const_generic_args(expr)
1162 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1163 self.partial_res_map.get(&id).cloned()
1166 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1167 self.import_res_map.get(&id).cloned().unwrap_or_default()
1170 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1171 self.label_res_map.get(&id).cloned()
1174 fn definitions(&mut self) -> &mut Definitions {
1175 &mut self.definitions
1178 fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
1179 StableHashingContext::new(self.session, &self.definitions, self.crate_loader.cstore())
1182 fn lint_buffer(&mut self) -> &mut LintBuffer {
1183 &mut self.lint_buffer
1186 fn next_node_id(&mut self) -> NodeId {
1190 fn take_trait_map(&mut self, node: NodeId) -> Option<Vec<TraitCandidate>> {
1191 self.trait_map.remove(&node)
1194 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1195 self.node_id_to_def_id.get(&node).copied()
1198 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1199 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1202 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1203 match def_id.as_local() {
1204 Some(def_id) => self.definitions.def_path_hash(def_id),
1205 None => self.cstore().def_path_hash(def_id),
1209 /// Adds a definition with a parent definition.
1213 node_id: ast::NodeId,
1219 !self.node_id_to_def_id.contains_key(&node_id),
1220 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1223 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1226 // Find the next free disambiguator for this key.
1227 let next_disambiguator = &mut self.next_disambiguator;
1228 let next_disambiguator = |parent, data| {
1229 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1230 let disambiguator = *next_disamb;
1231 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1235 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1237 // Some things for which we allocate `LocalDefId`s don't correspond to
1238 // anything in the AST, so they don't have a `NodeId`. For these cases
1239 // we don't need a mapping from `NodeId` to `LocalDefId`.
1240 if node_id != ast::DUMMY_NODE_ID {
1241 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1242 self.node_id_to_def_id.insert(node_id, def_id);
1244 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1250 impl<'a> Resolver<'a> {
1252 session: &'a Session,
1255 metadata_loader: Box<MetadataLoaderDyn>,
1256 arenas: &'a ResolverArenas<'a>,
1258 let root_def_id = CRATE_DEF_ID.to_def_id();
1259 let mut module_map = FxHashMap::default();
1260 let graph_root = arenas.new_module(
1262 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1265 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1268 let empty_module = arenas.new_module(
1270 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1274 &mut FxHashMap::default(),
1277 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1278 let root = definitions.get_root_def();
1280 let mut visibilities = FxHashMap::default();
1281 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1283 let mut def_id_to_node_id = IndexVec::default();
1284 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1285 let mut node_id_to_def_id = FxHashMap::default();
1286 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1288 let mut invocation_parents = FxHashMap::default();
1289 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1291 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1295 .filter(|(_, entry)| entry.add_prelude)
1296 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1299 if !session.contains_name(&krate.attrs, sym::no_core) {
1300 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1301 if !session.contains_name(&krate.attrs, sym::no_std) {
1302 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1306 let (registered_attrs, registered_tools) =
1307 macros::registered_attrs_and_tools(session, &krate.attrs);
1309 let features = session.features_untracked();
1311 let mut resolver = Resolver {
1316 // The outermost module has def ID 0; this is not reflected in the
1322 has_self: FxHashSet::default(),
1323 field_names: FxHashMap::default(),
1325 determined_imports: Vec::new(),
1326 indeterminate_imports: Vec::new(),
1328 last_import_segment: false,
1329 unusable_binding: None,
1331 pat_span_map: Default::default(),
1332 partial_res_map: Default::default(),
1333 import_res_map: Default::default(),
1334 label_res_map: Default::default(),
1335 extern_crate_map: Default::default(),
1336 export_map: FxHashMap::default(),
1337 trait_map: NodeMap::default(),
1338 underscore_disambiguator: 0,
1341 block_map: Default::default(),
1342 binding_parent_modules: FxHashMap::default(),
1343 ast_transform_scopes: FxHashMap::default(),
1345 glob_map: Default::default(),
1347 used_imports: FxHashSet::default(),
1348 maybe_unused_trait_imports: Default::default(),
1349 maybe_unused_extern_crates: Vec::new(),
1351 privacy_errors: Vec::new(),
1352 ambiguity_errors: Vec::new(),
1353 use_injections: Vec::new(),
1354 macro_expanded_macro_export_errors: BTreeSet::new(),
1357 dummy_binding: arenas.alloc_name_binding(NameBinding {
1358 kind: NameBindingKind::Res(Res::Err, false),
1360 expansion: LocalExpnId::ROOT,
1362 vis: ty::Visibility::Public,
1365 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1366 macro_names: FxHashSet::default(),
1367 builtin_macros: Default::default(),
1370 macro_use_prelude: FxHashMap::default(),
1371 all_macros: FxHashMap::default(),
1372 macro_map: FxHashMap::default(),
1373 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1374 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1375 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1376 invocation_parent_scopes: Default::default(),
1377 output_macro_rules_scopes: Default::default(),
1378 helper_attrs: Default::default(),
1379 derive_data: Default::default(),
1380 local_macro_def_scopes: FxHashMap::default(),
1381 name_already_seen: FxHashMap::default(),
1382 potentially_unused_imports: Vec::new(),
1383 struct_constructors: Default::default(),
1384 unused_macros: Default::default(),
1385 proc_macro_stubs: Default::default(),
1386 single_segment_macro_resolutions: Default::default(),
1387 multi_segment_macro_resolutions: Default::default(),
1388 builtin_attrs: Default::default(),
1389 containers_deriving_copy: Default::default(),
1390 active_features: features
1391 .declared_lib_features
1393 .map(|(feat, ..)| *feat)
1394 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1396 lint_buffer: LintBuffer::default(),
1397 next_node_id: CRATE_NODE_ID,
1400 placeholder_field_indices: Default::default(),
1402 next_disambiguator: Default::default(),
1403 trait_impl_items: Default::default(),
1404 legacy_const_generic_args: Default::default(),
1405 item_generics_num_lifetimes: Default::default(),
1406 main_def: Default::default(),
1407 trait_impls: Default::default(),
1408 proc_macros: Default::default(),
1409 confused_type_with_std_module: Default::default(),
1412 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1413 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1420 parent: Option<Module<'a>>,
1424 no_implicit_prelude: bool,
1426 let module_map = &mut self.module_map;
1427 self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
1430 pub fn next_node_id(&mut self) -> NodeId {
1432 self.next_node_id.as_u32().checked_add(1).expect("input too large; ran out of NodeIds");
1433 mem::replace(&mut self.next_node_id, ast::NodeId::from_u32(next))
1436 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1437 &mut self.lint_buffer
1440 pub fn arenas() -> ResolverArenas<'a> {
1444 pub fn into_outputs(self) -> ResolverOutputs {
1445 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1446 let definitions = self.definitions;
1447 let visibilities = self.visibilities;
1448 let extern_crate_map = self.extern_crate_map;
1449 let export_map = self.export_map;
1450 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1451 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1452 let glob_map = self.glob_map;
1453 let main_def = self.main_def;
1454 let confused_type_with_std_module = self.confused_type_with_std_module;
1457 cstore: Box::new(self.crate_loader.into_cstore()),
1462 maybe_unused_trait_imports,
1463 maybe_unused_extern_crates,
1464 extern_prelude: self
1467 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1470 trait_impls: self.trait_impls,
1472 confused_type_with_std_module,
1476 pub fn clone_outputs(&self) -> ResolverOutputs {
1477 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1479 definitions: self.definitions.clone(),
1480 cstore: Box::new(self.cstore().clone()),
1481 visibilities: self.visibilities.clone(),
1482 extern_crate_map: self.extern_crate_map.clone(),
1483 export_map: self.export_map.clone(),
1484 glob_map: self.glob_map.clone(),
1485 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1486 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1487 extern_prelude: self
1490 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1492 main_def: self.main_def,
1493 trait_impls: self.trait_impls.clone(),
1495 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1499 pub fn cstore(&self) -> &CStore {
1500 self.crate_loader.cstore()
1503 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1505 MacroKind::Bang => self.dummy_ext_bang.clone(),
1506 MacroKind::Derive => self.dummy_ext_derive.clone(),
1507 MacroKind::Attr => self.non_macro_attr.clone(),
1511 /// Runs the function on each namespace.
1512 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1518 fn is_builtin_macro(&mut self, res: Res) -> bool {
1519 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1522 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1524 match ctxt.outer_expn_data().macro_def_id {
1525 Some(def_id) => return def_id,
1526 None => ctxt.remove_mark(),
1531 /// Entry point to crate resolution.
1532 pub fn resolve_crate(&mut self, krate: &Crate) {
1533 self.session.time("resolve_crate", || {
1534 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1535 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1536 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1537 self.session.time("resolve_main", || self.resolve_main());
1538 self.session.time("resolve_check_unused", || self.check_unused(krate));
1539 self.session.time("resolve_report_errors", || self.report_errors(krate));
1540 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1544 pub fn traits_in_scope(
1546 current_trait: Option<Module<'a>>,
1547 parent_scope: &ParentScope<'a>,
1548 ctxt: SyntaxContext,
1549 assoc_item: Option<(Symbol, Namespace)>,
1550 ) -> Vec<TraitCandidate> {
1551 let mut found_traits = Vec::new();
1553 if let Some(module) = current_trait {
1554 if self.trait_may_have_item(Some(module), assoc_item) {
1555 let def_id = module.def_id();
1556 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1560 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1562 Scope::Module(module, _) => {
1563 this.traits_in_module(module, assoc_item, &mut found_traits);
1565 Scope::StdLibPrelude => {
1566 if let Some(module) = this.prelude {
1567 this.traits_in_module(module, assoc_item, &mut found_traits);
1570 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1571 _ => unreachable!(),
1579 fn traits_in_module(
1582 assoc_item: Option<(Symbol, Namespace)>,
1583 found_traits: &mut Vec<TraitCandidate>,
1585 module.ensure_traits(self);
1586 let traits = module.traits.borrow();
1587 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1588 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1589 let def_id = trait_binding.res().def_id();
1590 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1591 found_traits.push(TraitCandidate { def_id, import_ids });
1596 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1597 // associated item with the given name and namespace (if specified). This is a conservative
1598 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1599 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1600 // associated items.
1601 fn trait_may_have_item(
1603 trait_module: Option<Module<'a>>,
1604 assoc_item: Option<(Symbol, Namespace)>,
1606 match (trait_module, assoc_item) {
1607 (Some(trait_module), Some((name, ns))) => {
1608 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1609 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1610 assoc_ns == ns && assoc_ident.name == name
1617 fn find_transitive_imports(
1619 mut kind: &NameBindingKind<'_>,
1621 ) -> SmallVec<[LocalDefId; 1]> {
1622 let mut import_ids = smallvec![];
1623 while let NameBindingKind::Import { import, binding, .. } = kind {
1624 let id = self.local_def_id(import.id);
1625 self.maybe_unused_trait_imports.insert(id);
1626 self.add_to_glob_map(&import, trait_name);
1627 import_ids.push(id);
1628 kind = &binding.kind;
1633 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1634 let ident = ident.normalize_to_macros_2_0();
1635 let disambiguator = if ident.name == kw::Underscore {
1636 self.underscore_disambiguator += 1;
1637 self.underscore_disambiguator
1641 BindingKey { ident, ns, disambiguator }
1644 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1645 if module.populate_on_access.get() {
1646 module.populate_on_access.set(false);
1647 self.build_reduced_graph_external(module);
1649 &module.lazy_resolutions
1656 ) -> &'a RefCell<NameResolution<'a>> {
1658 .resolutions(module)
1661 .or_insert_with(|| self.arenas.alloc_name_resolution())
1667 used_binding: &'a NameBinding<'a>,
1668 is_lexical_scope: bool,
1670 if let Some((b2, kind)) = used_binding.ambiguity {
1671 self.ambiguity_errors.push(AmbiguityError {
1676 misc1: AmbiguityErrorMisc::None,
1677 misc2: AmbiguityErrorMisc::None,
1680 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1681 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1682 // but not introduce it, as used if they are accessed from lexical scope.
1683 if is_lexical_scope {
1684 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1685 if let Some(crate_item) = entry.extern_crate_item {
1686 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1693 import.used.set(true);
1694 self.used_imports.insert(import.id);
1695 self.add_to_glob_map(&import, ident);
1696 self.record_use(ident, binding, false);
1701 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1702 if import.is_glob() {
1703 let def_id = self.local_def_id(import.id);
1704 self.glob_map.entry(def_id).or_default().insert(ident.name);
1708 /// A generic scope visitor.
1709 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1710 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1713 scope_set: ScopeSet<'a>,
1714 parent_scope: &ParentScope<'a>,
1715 ctxt: SyntaxContext,
1716 mut visitor: impl FnMut(
1719 /*use_prelude*/ bool,
1723 // General principles:
1724 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1725 // built into the language or standard library. This way we can add new names into the
1726 // language or standard library without breaking user code.
1727 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1728 // Places to search (in order of decreasing priority):
1730 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1731 // (open set, not controlled).
1732 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1733 // (open, not controlled).
1734 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1735 // 4. Tool modules (closed, controlled right now, but not in the future).
1736 // 5. Standard library prelude (de-facto closed, controlled).
1737 // 6. Language prelude (closed, controlled).
1739 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1740 // (open set, not controlled).
1741 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1742 // (open, not controlled).
1743 // 3. Standard library prelude (de-facto closed, controlled).
1745 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1746 // are currently reported as errors. They should be higher in priority than preludes
1747 // and probably even names in modules according to the "general principles" above. They
1748 // also should be subject to restricted shadowing because are effectively produced by
1749 // derives (you need to resolve the derive first to add helpers into scope), but they
1750 // should be available before the derive is expanded for compatibility.
1751 // It's mess in general, so we are being conservative for now.
1752 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1753 // priority than prelude macros, but create ambiguities with macros in modules.
1754 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1755 // (open, not controlled). Have higher priority than prelude macros, but create
1756 // ambiguities with `macro_rules`.
1757 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1758 // 4a. User-defined prelude from macro-use
1759 // (open, the open part is from macro expansions, not controlled).
1760 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1761 // 4c. Standard library prelude (de-facto closed, controlled).
1762 // 6. Language prelude: builtin attributes (closed, controlled).
1764 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1765 let (ns, macro_kind, is_absolute_path) = match scope_set {
1766 ScopeSet::All(ns, _) => (ns, None, false),
1767 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1768 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1769 ScopeSet::Late(ns, ..) => (ns, None, false),
1771 let module = match scope_set {
1772 // Start with the specified module.
1773 ScopeSet::Late(_, module, _) => module,
1774 // Jump out of trait or enum modules, they do not act as scopes.
1775 _ => parent_scope.module.nearest_item_scope(),
1777 let mut scope = match ns {
1778 _ if is_absolute_path => Scope::CrateRoot,
1779 TypeNS | ValueNS => Scope::Module(module, None),
1780 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1782 let mut ctxt = ctxt.normalize_to_macros_2_0();
1783 let mut use_prelude = !module.no_implicit_prelude;
1786 let visit = match scope {
1787 // Derive helpers are not in scope when resolving derives in the same container.
1788 Scope::DeriveHelpers(expn_id) => {
1789 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1791 Scope::DeriveHelpersCompat => true,
1792 Scope::MacroRules(macro_rules_scope) => {
1793 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1794 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1795 // As another consequence of this optimization visitors never observe invocation
1796 // scopes for macros that were already expanded.
1797 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1798 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1799 macro_rules_scope.set(next_scope.get());
1806 Scope::CrateRoot => true,
1807 Scope::Module(..) => true,
1808 Scope::RegisteredAttrs => use_prelude,
1809 Scope::MacroUsePrelude => use_prelude || rust_2015,
1810 Scope::BuiltinAttrs => true,
1811 Scope::ExternPrelude => use_prelude || is_absolute_path,
1812 Scope::ToolPrelude => use_prelude,
1813 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1814 Scope::BuiltinTypes => true,
1818 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1819 return break_result;
1823 scope = match scope {
1824 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1825 Scope::DeriveHelpers(expn_id) => {
1826 // Derive helpers are not visible to code generated by bang or derive macros.
1827 let expn_data = expn_id.expn_data();
1828 match expn_data.kind {
1830 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1831 Scope::DeriveHelpersCompat
1833 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1836 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1837 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1838 MacroRulesScope::Binding(binding) => {
1839 Scope::MacroRules(binding.parent_macro_rules_scope)
1841 MacroRulesScope::Invocation(invoc_id) => {
1842 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1844 MacroRulesScope::Empty => Scope::Module(module, None),
1846 Scope::CrateRoot => match ns {
1848 ctxt.adjust(ExpnId::root());
1849 Scope::ExternPrelude
1851 ValueNS | MacroNS => break,
1853 Scope::Module(module, prev_lint_id) => {
1854 use_prelude = !module.no_implicit_prelude;
1855 let derive_fallback_lint_id = match scope_set {
1856 ScopeSet::Late(.., lint_id) => lint_id,
1859 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1860 Some((parent_module, lint_id)) => {
1861 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1864 ctxt.adjust(ExpnId::root());
1866 TypeNS => Scope::ExternPrelude,
1867 ValueNS => Scope::StdLibPrelude,
1868 MacroNS => Scope::RegisteredAttrs,
1873 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1874 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1875 Scope::BuiltinAttrs => break, // nowhere else to search
1876 Scope::ExternPrelude if is_absolute_path => break,
1877 Scope::ExternPrelude => Scope::ToolPrelude,
1878 Scope::ToolPrelude => Scope::StdLibPrelude,
1879 Scope::StdLibPrelude => match ns {
1880 TypeNS => Scope::BuiltinTypes,
1881 ValueNS => break, // nowhere else to search
1882 MacroNS => Scope::BuiltinAttrs,
1884 Scope::BuiltinTypes => break, // nowhere else to search
1891 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1892 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1893 /// `ident` in the first scope that defines it (or None if no scopes define it).
1895 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1896 /// the items are defined in the block. For example,
1899 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1902 /// g(); // This resolves to the local variable `g` since it shadows the item.
1906 /// Invariant: This must only be called during main resolution, not during
1907 /// import resolution.
1908 fn resolve_ident_in_lexical_scope(
1912 parent_scope: &ParentScope<'a>,
1913 record_used_id: Option<NodeId>,
1916 ) -> Option<LexicalScopeBinding<'a>> {
1917 assert!(ns == TypeNS || ns == ValueNS);
1918 let orig_ident = ident;
1919 if ident.name == kw::Empty {
1920 return Some(LexicalScopeBinding::Res(Res::Err));
1922 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1923 // FIXME(jseyfried) improve `Self` hygiene
1924 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1925 (empty_span, empty_span)
1926 } else if ns == TypeNS {
1927 let normalized_span = ident.span.normalize_to_macros_2_0();
1928 (normalized_span, normalized_span)
1930 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1932 ident.span = general_span;
1933 let normalized_ident = Ident { span: normalized_span, ..ident };
1935 // Walk backwards up the ribs in scope.
1936 let record_used = record_used_id.is_some();
1937 let mut module = self.graph_root;
1938 for i in (0..ribs.len()).rev() {
1939 debug!("walk rib\n{:?}", ribs[i].bindings);
1940 // Use the rib kind to determine whether we are resolving parameters
1941 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1942 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1943 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1945 // The ident resolves to a type parameter or local variable.
1946 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1952 *original_rib_ident_def,
1957 module = match ribs[i].kind {
1958 ModuleRibKind(module) => module,
1959 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1960 // If an invocation of this macro created `ident`, give up on `ident`
1961 // and switch to `ident`'s source from the macro definition.
1962 ident.span.remove_mark();
1969 ModuleKind::Block(..) => {} // We can see through blocks
1973 let item = self.resolve_ident_in_module_unadjusted(
1974 ModuleOrUniformRoot::Module(module),
1981 if let Ok(binding) = item {
1982 // The ident resolves to an item.
1983 return Some(LexicalScopeBinding::Item(binding));
1986 self.early_resolve_ident_in_lexical_scope(
1988 ScopeSet::Late(ns, module, record_used_id),
1995 .map(LexicalScopeBinding::Item)
1998 fn hygienic_lexical_parent(
2001 ctxt: &mut SyntaxContext,
2002 derive_fallback_lint_id: Option<NodeId>,
2003 ) -> Option<(Module<'a>, Option<NodeId>)> {
2004 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2005 return Some((self.expn_def_scope(ctxt.remove_mark()), None));
2008 if let ModuleKind::Block(..) = module.kind {
2009 return Some((module.parent.unwrap().nearest_item_scope(), None));
2012 // We need to support the next case under a deprecation warning
2015 // ---- begin: this comes from a proc macro derive
2016 // mod implementation_details {
2017 // // Note that `MyStruct` is not in scope here.
2018 // impl SomeTrait for MyStruct { ... }
2022 // So we have to fall back to the module's parent during lexical resolution in this case.
2023 if derive_fallback_lint_id.is_some() {
2024 if let Some(parent) = module.parent {
2025 // Inner module is inside the macro, parent module is outside of the macro.
2026 if module.expansion != parent.expansion
2027 && module.expansion.is_descendant_of(parent.expansion)
2029 // The macro is a proc macro derive
2030 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2031 let ext = self.get_macro_by_def_id(def_id);
2032 if ext.builtin_name.is_none()
2033 && ext.macro_kind() == MacroKind::Derive
2034 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2036 return Some((parent, derive_fallback_lint_id));
2046 fn resolve_ident_in_module(
2048 module: ModuleOrUniformRoot<'a>,
2051 parent_scope: &ParentScope<'a>,
2054 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2055 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2056 .map_err(|(determinacy, _)| determinacy)
2059 fn resolve_ident_in_module_ext(
2061 module: ModuleOrUniformRoot<'a>,
2064 parent_scope: &ParentScope<'a>,
2067 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2068 let tmp_parent_scope;
2069 let mut adjusted_parent_scope = parent_scope;
2071 ModuleOrUniformRoot::Module(m) => {
2072 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2074 ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
2075 adjusted_parent_scope = &tmp_parent_scope;
2078 ModuleOrUniformRoot::ExternPrelude => {
2079 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2081 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2085 self.resolve_ident_in_module_unadjusted_ext(
2089 adjusted_parent_scope,
2096 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2097 debug!("resolve_crate_root({:?})", ident);
2098 let mut ctxt = ident.span.ctxt();
2099 let mark = if ident.name == kw::DollarCrate {
2100 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2101 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2102 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2103 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2104 // definitions actually produced by `macro` and `macro` definitions produced by
2105 // `macro_rules!`, but at least such configurations are not stable yet.
2106 ctxt = ctxt.normalize_to_macro_rules();
2108 "resolve_crate_root: marks={:?}",
2109 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2111 let mut iter = ctxt.marks().into_iter().rev().peekable();
2112 let mut result = None;
2113 // Find the last opaque mark from the end if it exists.
2114 while let Some(&(mark, transparency)) = iter.peek() {
2115 if transparency == Transparency::Opaque {
2116 result = Some(mark);
2123 "resolve_crate_root: found opaque mark {:?} {:?}",
2125 result.map(|r| r.expn_data())
2127 // Then find the last semi-transparent mark from the end if it exists.
2128 for (mark, transparency) in iter {
2129 if transparency == Transparency::SemiTransparent {
2130 result = Some(mark);
2136 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2138 result.map(|r| r.expn_data())
2142 debug!("resolve_crate_root: not DollarCrate");
2143 ctxt = ctxt.normalize_to_macros_2_0();
2144 ctxt.adjust(ExpnId::root())
2146 let module = match mark {
2147 Some(def) => self.expn_def_scope(def),
2150 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2153 return self.graph_root;
2156 let module = self.expect_module(
2157 module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(),
2160 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2169 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2170 let mut module = self.expect_module(module.nearest_parent_mod());
2171 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2172 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
2173 module = self.expect_module(parent.nearest_parent_mod());
2181 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2182 parent_scope: &ParentScope<'a>,
2185 crate_lint: CrateLint,
2186 ) -> PathResult<'a> {
2187 self.resolve_path_with_ribs(
2198 fn resolve_path_with_ribs(
2201 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2202 parent_scope: &ParentScope<'a>,
2205 crate_lint: CrateLint,
2206 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2207 ) -> PathResult<'a> {
2208 let mut module = None;
2209 let mut allow_super = true;
2210 let mut second_binding = None;
2213 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2214 path_span={:?}, crate_lint={:?})",
2215 path, opt_ns, record_used, path_span, crate_lint,
2218 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2219 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2220 let record_segment_res = |this: &mut Self, res| {
2222 if let Some(id) = id {
2223 if !this.partial_res_map.contains_key(&id) {
2224 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2225 this.record_partial_res(id, PartialRes::new(res));
2231 let is_last = i == path.len() - 1;
2232 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2233 let name = ident.name;
2235 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2238 if allow_super && name == kw::Super {
2239 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2240 let self_module = match i {
2241 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2243 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2247 if let Some(self_module) = self_module {
2248 if let Some(parent) = self_module.parent {
2249 module = Some(ModuleOrUniformRoot::Module(
2250 self.resolve_self(&mut ctxt, parent),
2255 let msg = "there are too many leading `super` keywords".to_string();
2256 return PathResult::Failed {
2260 is_error_from_last_segment: false,
2264 if name == kw::SelfLower {
2265 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2266 module = Some(ModuleOrUniformRoot::Module(
2267 self.resolve_self(&mut ctxt, parent_scope.module),
2271 if name == kw::PathRoot && ident.span.rust_2018() {
2272 module = Some(ModuleOrUniformRoot::ExternPrelude);
2275 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2276 // `::a::b` from 2015 macro on 2018 global edition
2277 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2280 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2281 // `::a::b`, `crate::a::b` or `$crate::a::b`
2282 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2288 // Report special messages for path segment keywords in wrong positions.
2289 if ident.is_path_segment_keyword() && i != 0 {
2290 let name_str = if name == kw::PathRoot {
2291 "crate root".to_string()
2293 format!("`{}`", name)
2295 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2296 format!("global paths cannot start with {}", name_str)
2298 format!("{} in paths can only be used in start position", name_str)
2300 return PathResult::Failed {
2304 is_error_from_last_segment: false,
2308 enum FindBindingResult<'a> {
2309 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2310 PathResult(PathResult<'a>),
2312 let find_binding_in_ns = |this: &mut Self, ns| {
2313 let binding = if let Some(module) = module {
2314 this.resolve_ident_in_module(
2322 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2323 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2324 this.early_resolve_ident_in_lexical_scope(
2333 let record_used_id = if record_used {
2334 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2338 match this.resolve_ident_in_lexical_scope(
2346 // we found a locally-imported or available item/module
2347 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2348 // we found a local variable or type param
2349 Some(LexicalScopeBinding::Res(res))
2350 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2352 record_segment_res(this, res);
2353 return FindBindingResult::PathResult(PathResult::NonModule(
2354 PartialRes::with_unresolved_segments(res, path.len() - 1),
2357 _ => Err(Determinacy::determined(record_used)),
2360 FindBindingResult::Binding(binding)
2362 let binding = match find_binding_in_ns(self, ns) {
2363 FindBindingResult::PathResult(x) => return x,
2364 FindBindingResult::Binding(binding) => binding,
2369 second_binding = Some(binding);
2371 let res = binding.res();
2372 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2373 if let Some(next_module) = binding.module() {
2374 module = Some(ModuleOrUniformRoot::Module(next_module));
2375 record_segment_res(self, res);
2376 } else if res == Res::ToolMod && i + 1 != path.len() {
2377 if binding.is_import() {
2381 "cannot use a tool module through an import",
2383 .span_note(binding.span, "the tool module imported here")
2386 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2387 return PathResult::NonModule(PartialRes::new(res));
2388 } else if res == Res::Err {
2389 return PathResult::NonModule(PartialRes::new(Res::Err));
2390 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2391 self.lint_if_path_starts_with_module(
2397 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2402 let label = format!(
2403 "`{}` is {} {}, not a module",
2409 return PathResult::Failed {
2413 is_error_from_last_segment: is_last,
2417 Err(Undetermined) => return PathResult::Indeterminate,
2418 Err(Determined) => {
2419 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2420 if opt_ns.is_some() && !module.is_normal() {
2421 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2422 module.res().unwrap(),
2427 let module_res = match module {
2428 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2431 let (label, suggestion) = if module_res == self.graph_root.res() {
2432 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2433 // Don't look up import candidates if this is a speculative resolve
2434 let mut candidates = if record_used {
2435 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2439 candidates.sort_by_cached_key(|c| {
2440 (c.path.segments.len(), pprust::path_to_string(&c.path))
2442 if let Some(candidate) = candidates.get(0) {
2444 String::from("unresolved import"),
2446 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2447 String::from("a similar path exists"),
2448 Applicability::MaybeIncorrect,
2451 } else if self.session.edition() == Edition::Edition2015 {
2452 (format!("maybe a missing crate `{}`?", ident), None)
2454 (format!("could not find `{}` in the crate root", ident), None)
2462 .map_or(false, |c| c.is_ascii_uppercase())
2464 // Check whether the name refers to an item in the value namespace.
2465 let suggestion = if ribs.is_some() {
2466 let match_span = match self.resolve_ident_in_lexical_scope(
2472 &ribs.unwrap()[ValueNS],
2474 // Name matches a local variable. For example:
2477 // let Foo: &str = "";
2478 // println!("{}", Foo::Bar); // Name refers to local
2479 // // variable `Foo`.
2482 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2483 Some(*self.pat_span_map.get(&id).unwrap())
2486 // Name matches item from a local name binding
2487 // created by `use` declaration. For example:
2489 // pub Foo: &str = "";
2493 // println!("{}", Foo::Bar); // Name refers to local
2494 // // binding `Foo`.
2497 Some(LexicalScopeBinding::Item(name_binding)) => {
2498 Some(name_binding.span)
2503 if let Some(span) = match_span {
2505 vec![(span, String::from(""))],
2506 format!("`{}` is defined here, but is not a type", ident),
2507 Applicability::MaybeIncorrect,
2516 (format!("use of undeclared type `{}`", ident), suggestion)
2519 format!("use of undeclared crate or module `{}`", ident),
2520 if ident.name == sym::alloc {
2524 "add `extern crate alloc` to use the `alloc` crate",
2526 Applicability::MaybeIncorrect,
2529 self.find_similarly_named_module_or_crate(
2531 &parent_scope.module,
2535 vec![(ident.span, sugg.to_string())],
2537 "there is a crate or module with a similar name",
2539 Applicability::MaybeIncorrect,
2546 let parent = path[i - 1].ident.name;
2547 let parent = match parent {
2548 // ::foo is mounted at the crate root for 2015, and is the extern
2549 // prelude for 2018+
2550 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2551 "the list of imported crates".to_owned()
2553 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2555 format!("`{}`", parent)
2559 let mut msg = format!("could not find `{}` in {}", ident, parent);
2560 if ns == TypeNS || ns == ValueNS {
2561 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2562 if let FindBindingResult::Binding(Ok(binding)) =
2563 find_binding_in_ns(self, ns_to_try)
2565 let mut found = |what| {
2567 "expected {}, found {} `{}` in {}",
2574 if binding.module().is_some() {
2577 match binding.res() {
2578 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2579 _ => found(ns_to_try.descr()),
2586 return PathResult::Failed {
2590 is_error_from_last_segment: is_last,
2596 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2598 PathResult::Module(match module {
2599 Some(module) => module,
2600 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2601 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2605 fn lint_if_path_starts_with_module(
2607 crate_lint: CrateLint,
2610 second_binding: Option<&NameBinding<'_>>,
2612 let (diag_id, diag_span) = match crate_lint {
2613 CrateLint::No => return,
2614 CrateLint::SimplePath(id) => (id, path_span),
2615 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2616 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2619 let first_name = match path.get(0) {
2620 // In the 2018 edition this lint is a hard error, so nothing to do
2621 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2625 // We're only interested in `use` paths which should start with
2626 // `{{root}}` currently.
2627 if first_name != kw::PathRoot {
2632 // If this import looks like `crate::...` it's already good
2633 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2634 // Otherwise go below to see if it's an extern crate
2636 // If the path has length one (and it's `PathRoot` most likely)
2637 // then we don't know whether we're gonna be importing a crate or an
2638 // item in our crate. Defer this lint to elsewhere
2642 // If the first element of our path was actually resolved to an
2643 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2644 // warning, this looks all good!
2645 if let Some(binding) = second_binding {
2646 if let NameBindingKind::Import { import, .. } = binding.kind {
2647 // Careful: we still want to rewrite paths from renamed extern crates.
2648 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2654 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2655 self.lint_buffer.buffer_lint_with_diagnostic(
2656 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2659 "absolute paths must start with `self`, `super`, \
2660 `crate`, or an external crate name in the 2018 edition",
2665 // Validate a local resolution (from ribs).
2666 fn validate_res_from_ribs(
2673 original_rib_ident_def: Ident,
2674 all_ribs: &[Rib<'a>],
2676 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2677 debug!("validate_res_from_ribs({:?})", res);
2678 let ribs = &all_ribs[rib_index + 1..];
2680 // An invalid forward use of a generic parameter from a previous default.
2681 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2683 let res_error = if rib_ident.name == kw::SelfUpper {
2684 ResolutionError::SelfInGenericParamDefault
2686 ResolutionError::ForwardDeclaredGenericParam
2688 self.report_error(span, res_error);
2690 assert_eq!(res, Res::Err);
2696 use ResolutionError::*;
2697 let mut res_err = None;
2702 | ClosureOrAsyncRibKind
2704 | MacroDefinition(..)
2705 | ForwardGenericParamBanRibKind => {
2706 // Nothing to do. Continue.
2708 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2709 // This was an attempt to access an upvar inside a
2710 // named function item. This is not allowed, so we
2713 // We don't immediately trigger a resolve error, because
2714 // we want certain other resolution errors (namely those
2715 // emitted for `ConstantItemRibKind` below) to take
2717 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2720 ConstantItemRibKind(_, item) => {
2721 // Still doesn't deal with upvars
2723 let (span, resolution_error) =
2724 if let Some((ident, constant_item_kind)) = item {
2725 let kind_str = match constant_item_kind {
2726 ConstantItemKind::Const => "const",
2727 ConstantItemKind::Static => "static",
2731 AttemptToUseNonConstantValueInConstant(
2732 ident, "let", kind_str,
2738 AttemptToUseNonConstantValueInConstant(
2739 original_rib_ident_def,
2745 self.report_error(span, resolution_error);
2749 ConstParamTyRibKind => {
2751 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2757 if let Some(res_err) = res_err {
2758 self.report_error(span, res_err);
2762 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2764 let has_generic_params: HasGenericParams = match rib.kind {
2766 | ClosureOrAsyncRibKind
2769 | MacroDefinition(..)
2770 | ForwardGenericParamBanRibKind => {
2771 // Nothing to do. Continue.
2775 ConstantItemRibKind(trivial, _) => {
2776 let features = self.session.features_untracked();
2777 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2778 if !(trivial || features.generic_const_exprs) {
2779 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2780 // we can't easily tell if it's generic at this stage, so we instead remember
2781 // this and then enforce the self type to be concrete later on.
2782 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2783 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2788 ResolutionError::ParamInNonTrivialAnonConst {
2789 name: rib_ident.name,
2795 self.session.delay_span_bug(span, CG_BUG_STR);
2803 // This was an attempt to use a type parameter outside its scope.
2804 ItemRibKind(has_generic_params) => has_generic_params,
2805 FnItemRibKind => HasGenericParams::Yes,
2806 ConstParamTyRibKind => {
2810 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2820 ResolutionError::GenericParamsFromOuterFunction(
2829 Res::Def(DefKind::ConstParam, _) => {
2830 let mut ribs = ribs.iter().peekable();
2831 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2832 // When declaring const parameters inside function signatures, the first rib
2833 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2834 // (spuriously) conflicting with the const param.
2839 let has_generic_params = match rib.kind {
2841 | ClosureOrAsyncRibKind
2844 | MacroDefinition(..)
2845 | ForwardGenericParamBanRibKind => continue,
2847 ConstantItemRibKind(trivial, _) => {
2848 let features = self.session.features_untracked();
2849 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2850 if !(trivial || features.generic_const_exprs) {
2854 ResolutionError::ParamInNonTrivialAnonConst {
2855 name: rib_ident.name,
2861 self.session.delay_span_bug(span, CG_BUG_STR);
2868 ItemRibKind(has_generic_params) => has_generic_params,
2869 FnItemRibKind => HasGenericParams::Yes,
2870 ConstParamTyRibKind => {
2874 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2881 // This was an attempt to use a const parameter outside its scope.
2885 ResolutionError::GenericParamsFromOuterFunction(
2899 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2900 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2901 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2902 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2906 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2907 debug!("(recording pat) recording {:?} for {:?}", node, span);
2908 self.pat_span_map.insert(node, span);
2911 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2912 vis.is_accessible_from(module.nearest_parent_mod(), self)
2915 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2916 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2917 if !ptr::eq(module, old_module) {
2918 span_bug!(binding.span, "parent module is reset for binding");
2923 fn disambiguate_macro_rules_vs_modularized(
2925 macro_rules: &'a NameBinding<'a>,
2926 modularized: &'a NameBinding<'a>,
2928 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2929 // is disambiguated to mitigate regressions from macro modularization.
2930 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2932 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2933 self.binding_parent_modules.get(&PtrKey(modularized)),
2935 (Some(macro_rules), Some(modularized)) => {
2936 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
2937 && modularized.is_ancestor_of(macro_rules)
2943 fn report_errors(&mut self, krate: &Crate) {
2944 self.report_with_use_injections(krate);
2946 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2947 let msg = "macro-expanded `macro_export` macros from the current crate \
2948 cannot be referred to by absolute paths";
2949 self.lint_buffer.buffer_lint_with_diagnostic(
2950 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2954 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2958 for ambiguity_error in &self.ambiguity_errors {
2959 self.report_ambiguity_error(ambiguity_error);
2962 let mut reported_spans = FxHashSet::default();
2963 for error in &self.privacy_errors {
2964 if reported_spans.insert(error.dedup_span) {
2965 self.report_privacy_error(error);
2970 fn report_with_use_injections(&mut self, krate: &Crate) {
2971 for UseError { mut err, candidates, def_id, instead, suggestion } in
2972 self.use_injections.drain(..)
2974 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2975 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2979 if !candidates.is_empty() {
2980 diagnostics::show_candidates(
2989 } else if let Some((span, msg, sugg, appl)) = suggestion {
2990 err.span_suggestion(span, msg, sugg, appl);
2996 fn report_conflict<'b>(
3001 new_binding: &NameBinding<'b>,
3002 old_binding: &NameBinding<'b>,
3004 // Error on the second of two conflicting names
3005 if old_binding.span.lo() > new_binding.span.lo() {
3006 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3009 let container = match parent.kind {
3010 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
3011 ModuleKind::Block(..) => "block",
3014 let old_noun = match old_binding.is_import() {
3016 false => "definition",
3019 let new_participle = match new_binding.is_import() {
3025 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3027 if let Some(s) = self.name_already_seen.get(&name) {
3033 let old_kind = match (ns, old_binding.module()) {
3034 (ValueNS, _) => "value",
3035 (MacroNS, _) => "macro",
3036 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3037 (TypeNS, Some(module)) if module.is_normal() => "module",
3038 (TypeNS, Some(module)) if module.is_trait() => "trait",
3039 (TypeNS, _) => "type",
3042 let msg = format!("the name `{}` is defined multiple times", name);
3044 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3045 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3046 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3047 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3048 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3050 _ => match (old_binding.is_import(), new_binding.is_import()) {
3051 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3052 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3053 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3058 "`{}` must be defined only once in the {} namespace of this {}",
3064 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3066 self.session.source_map().guess_head_span(old_binding.span),
3067 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3070 // See https://github.com/rust-lang/rust/issues/32354
3071 use NameBindingKind::Import;
3072 let import = match (&new_binding.kind, &old_binding.kind) {
3073 // If there are two imports where one or both have attributes then prefer removing the
3074 // import without attributes.
3075 (Import { import: new, .. }, Import { import: old, .. })
3077 !new_binding.span.is_dummy()
3078 && !old_binding.span.is_dummy()
3079 && (new.has_attributes || old.has_attributes)
3082 if old.has_attributes {
3083 Some((new, new_binding.span, true))
3085 Some((old, old_binding.span, true))
3088 // Otherwise prioritize the new binding.
3089 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3090 Some((import, new_binding.span, other.is_import()))
3092 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3093 Some((import, old_binding.span, other.is_import()))
3098 // Check if the target of the use for both bindings is the same.
3099 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3100 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3102 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3103 // Only suggest removing an import if both bindings are to the same def, if both spans
3104 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3105 // been introduced by an item.
3106 let should_remove_import = duplicate
3108 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3111 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3112 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3114 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3115 // Simple case - remove the entire import. Due to the above match arm, this can
3116 // only be a single use so just remove it entirely.
3117 err.tool_only_span_suggestion(
3118 import.use_span_with_attributes,
3119 "remove unnecessary import",
3121 Applicability::MaybeIncorrect,
3124 Some((import, span, _)) => {
3125 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3131 self.name_already_seen.insert(name, span);
3134 /// This function adds a suggestion to change the binding name of a new import that conflicts
3135 /// with an existing import.
3137 /// ```text,ignore (diagnostic)
3138 /// help: you can use `as` to change the binding name of the import
3140 /// LL | use foo::bar as other_bar;
3141 /// | ^^^^^^^^^^^^^^^^^^^^^
3143 fn add_suggestion_for_rename_of_use(
3145 err: &mut DiagnosticBuilder<'_>,
3147 import: &Import<'_>,
3150 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3151 format!("Other{}", name)
3153 format!("other_{}", name)
3156 let mut suggestion = None;
3158 ImportKind::Single { type_ns_only: true, .. } => {
3159 suggestion = Some(format!("self as {}", suggested_name))
3161 ImportKind::Single { source, .. } => {
3163 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3165 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3166 if pos <= snippet.len() {
3167 suggestion = Some(format!(
3171 if snippet.ends_with(';') { ";" } else { "" }
3177 ImportKind::ExternCrate { source, target, .. } => {
3178 suggestion = Some(format!(
3179 "extern crate {} as {};",
3180 source.unwrap_or(target.name),
3184 _ => unreachable!(),
3187 let rename_msg = "you can use `as` to change the binding name of the import";
3188 if let Some(suggestion) = suggestion {
3189 err.span_suggestion(
3193 Applicability::MaybeIncorrect,
3196 err.span_label(binding_span, rename_msg);
3200 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3201 /// nested. In the following example, this function will be invoked to remove the `a` binding
3202 /// in the second use statement:
3204 /// ```ignore (diagnostic)
3205 /// use issue_52891::a;
3206 /// use issue_52891::{d, a, e};
3209 /// The following suggestion will be added:
3211 /// ```ignore (diagnostic)
3212 /// use issue_52891::{d, a, e};
3213 /// ^-- help: remove unnecessary import
3216 /// If the nested use contains only one import then the suggestion will remove the entire
3219 /// It is expected that the provided import is nested - this isn't checked by the
3220 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3221 /// as characters expected by span manipulations won't be present.
3222 fn add_suggestion_for_duplicate_nested_use(
3224 err: &mut DiagnosticBuilder<'_>,
3225 import: &Import<'_>,
3228 assert!(import.is_nested());
3229 let message = "remove unnecessary import";
3231 // Two examples will be used to illustrate the span manipulations we're doing:
3233 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3234 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3235 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3236 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3238 let (found_closing_brace, span) =
3239 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3241 // If there was a closing brace then identify the span to remove any trailing commas from
3242 // previous imports.
3243 if found_closing_brace {
3244 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3245 err.tool_only_span_suggestion(
3249 Applicability::MaybeIncorrect,
3252 // Remove the entire line if we cannot extend the span back, this indicates an
3253 // `issue_52891::{self}` case.
3254 err.span_suggestion(
3255 import.use_span_with_attributes,
3258 Applicability::MaybeIncorrect,
3265 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3268 fn extern_prelude_get(
3272 ) -> Option<&'a NameBinding<'a>> {
3273 if ident.is_path_segment_keyword() {
3274 // Make sure `self`, `super` etc produce an error when passed to here.
3277 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3278 if let Some(binding) = entry.extern_crate_item {
3279 if !speculative && entry.introduced_by_item {
3280 self.record_use(ident, binding, false);
3284 let crate_id = if !speculative {
3285 let Some(crate_id) =
3286 self.crate_loader.process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
3289 self.crate_loader.maybe_process_path_extern(ident.name)?
3291 let crate_root = self.expect_module(crate_id.as_def_id());
3293 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3294 .to_name_binding(self.arenas),
3300 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3301 /// isn't something that can be returned because it can't be made to live that long,
3302 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3303 /// just that an error occurred.
3304 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3305 pub fn resolve_str_path_error(
3311 ) -> Result<(ast::Path, Res), ()> {
3312 let path = if path_str.starts_with("::") {
3315 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3316 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3317 .map(|i| self.new_ast_path_segment(i))
3326 .map(Ident::from_str)
3327 .map(|i| self.new_ast_path_segment(i))
3332 let module = self.expect_module(module_id);
3333 let parent_scope = &ParentScope::module(module, self);
3334 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3338 // Resolve a path passed from rustdoc or HIR lowering.
3339 fn resolve_ast_path(
3343 parent_scope: &ParentScope<'a>,
3344 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3345 match self.resolve_path(
3346 &Segment::from_path(path),
3353 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3354 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3355 Ok(path_res.base_res())
3357 PathResult::NonModule(..) => Err((
3359 ResolutionError::FailedToResolve {
3360 label: String::from("type-relative paths are not supported in this context"),
3364 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3365 PathResult::Failed { span, label, suggestion, .. } => {
3366 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3371 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3372 let mut seg = ast::PathSegment::from_ident(ident);
3373 seg.id = self.next_node_id();
3378 pub fn graph_root(&self) -> Module<'a> {
3383 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3387 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3389 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3390 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3393 /// Checks if an expression refers to a function marked with
3394 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3395 /// from the attribute.
3396 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3397 if let ExprKind::Path(None, path) = &expr.kind {
3398 // Don't perform legacy const generics rewriting if the path already
3399 // has generic arguments.
3400 if path.segments.last().unwrap().args.is_some() {
3404 let partial_res = self.partial_res_map.get(&expr.id)?;
3405 if partial_res.unresolved_segments() != 0 {
3409 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3410 // We only support cross-crate argument rewriting. Uses
3411 // within the same crate should be updated to use the new
3412 // const generics style.
3413 if def_id.is_local() {
3417 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3423 .item_attrs(def_id, self.session)
3425 .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3426 let mut ret = Vec::new();
3427 for meta in attr.meta_item_list()? {
3428 match meta.literal()?.kind {
3429 LitKind::Int(a, _) => ret.push(a as usize),
3430 _ => panic!("invalid arg index"),
3433 // Cache the lookup to avoid parsing attributes for an iterm multiple times.
3434 self.legacy_const_generic_args.insert(def_id, Some(ret.clone()));
3441 fn resolve_main(&mut self) {
3442 let module = self.graph_root;
3443 let ident = Ident::with_dummy_span(sym::main);
3444 let parent_scope = &ParentScope::module(module, self);
3446 let name_binding = match self.resolve_ident_in_module(
3447 ModuleOrUniformRoot::Module(module),
3454 Ok(name_binding) => name_binding,
3458 let res = name_binding.res();
3459 let is_import = name_binding.is_import();
3460 let span = name_binding.span;
3461 if let Res::Def(DefKind::Fn, _) = res {
3462 self.record_use(ident, name_binding, false);
3464 self.main_def = Some(MainDefinition { res, is_import, span });
3468 fn names_to_string(names: &[Symbol]) -> String {
3469 let mut result = String::new();
3470 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3472 result.push_str("::");
3474 if Ident::with_dummy_span(*name).is_raw_guess() {
3475 result.push_str("r#");
3477 result.push_str(name.as_str());
3482 fn path_names_to_string(path: &Path) -> String {
3483 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3486 /// A somewhat inefficient routine to obtain the name of a module.
3487 fn module_to_string(module: Module<'_>) -> Option<String> {
3488 let mut names = Vec::new();
3490 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3491 if let ModuleKind::Def(.., name) = module.kind {
3492 if let Some(parent) = module.parent {
3494 collect_mod(names, parent);
3497 names.push(Symbol::intern("<opaque>"));
3498 collect_mod(names, module.parent.unwrap());
3501 collect_mod(&mut names, module);
3503 if names.is_empty() {
3507 Some(names_to_string(&names))
3510 #[derive(Copy, Clone, Debug)]
3512 /// Do not issue the lint.
3515 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3516 /// In this case, we can take the span of that path.
3519 /// This lint comes from a `use` statement. In this case, what we
3520 /// care about really is the *root* `use` statement; e.g., if we
3521 /// have nested things like `use a::{b, c}`, we care about the
3523 UsePath { root_id: NodeId, root_span: Span },
3525 /// This is the "trait item" from a fully qualified path. For example,
3526 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3527 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3528 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3532 fn node_id(&self) -> Option<NodeId> {
3534 CrateLint::No => None,
3535 CrateLint::SimplePath(id)
3536 | CrateLint::UsePath { root_id: id, .. }
3537 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3542 pub fn provide(providers: &mut Providers) {
3543 late::lifetimes::provide(providers);