1 // ignore-tidy-filelength
3 //! This crate is responsible for the part of name resolution that doesn't require type checker.
5 //! Module structure of the crate is built here.
6 //! Paths in macros, imports, expressions, types, patterns are resolved here.
7 //! Label and lifetime names are resolved here as well.
9 //! Type-relative name resolution (methods, fields, associated items) happens in `rustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
12 #![feature(box_patterns)]
13 #![feature(drain_filter)]
14 #![feature(bool_to_option)]
15 #![feature(crate_visibility_modifier)]
16 #![feature(format_args_capture)]
18 #![feature(never_type)]
20 #![recursion_limit = "256"]
21 #![allow(rustdoc::private_intra_doc_links)]
26 pub use rustc_hir::def::{Namespace, PerNS};
30 use rustc_arena::{DroplessArena, TypedArena};
31 use rustc_ast::node_id::NodeMap;
32 use rustc_ast::ptr::P;
33 use rustc_ast::visit::{self, Visitor};
34 use rustc_ast::{self as ast, NodeId};
35 use rustc_ast::{Crate, CRATE_NODE_ID};
36 use rustc_ast::{Expr, ExprKind, LitKind};
37 use rustc_ast::{ItemKind, ModKind, Path};
38 use rustc_ast_lowering::ResolverAstLowering;
39 use rustc_ast_pretty::pprust;
40 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
41 use rustc_data_structures::ptr_key::PtrKey;
42 use rustc_data_structures::sync::Lrc;
43 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
44 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
45 use rustc_hir::def::Namespace::*;
46 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
47 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
48 use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
49 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
50 use rustc_hir::TraitCandidate;
51 use rustc_index::vec::IndexVec;
52 use rustc_metadata::creader::{CStore, CrateLoader};
53 use rustc_middle::hir::exports::ExportMap;
54 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
55 use rustc_middle::span_bug;
56 use rustc_middle::ty::query::Providers;
57 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
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::{CachingSourceMapView, 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, 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)) => {
416 lhs.def_id() == rhs.def_id()
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) -> Option<DefId> {
607 ModuleKind::Def(_, def_id, _) => Some(def_id),
612 // `self` resolves to the first module ancestor that `is_normal`.
613 fn is_normal(&self) -> bool {
614 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
617 fn is_trait(&self) -> bool {
618 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
621 fn nearest_item_scope(&'a self) -> Module<'a> {
623 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
624 self.parent.expect("enum or trait module without a parent")
630 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
631 /// This may be the crate root.
632 fn nearest_parent_mod(&self) -> DefId {
634 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
635 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
639 fn is_ancestor_of(&self, mut other: &Self) -> bool {
640 while !ptr::eq(self, other) {
641 if let Some(parent) = other.parent {
651 impl<'a> fmt::Debug for ModuleData<'a> {
652 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
653 write!(f, "{:?}", self.res())
657 /// Records a possibly-private value, type, or module definition.
658 #[derive(Clone, Debug)]
659 pub struct NameBinding<'a> {
660 kind: NameBindingKind<'a>,
661 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
662 expansion: LocalExpnId,
667 pub trait ToNameBinding<'a> {
668 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
671 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
672 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
677 #[derive(Clone, Debug)]
678 enum NameBindingKind<'a> {
679 Res(Res, /* is_macro_export */ bool),
681 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
684 impl<'a> NameBindingKind<'a> {
685 /// Is this a name binding of an import?
686 fn is_import(&self) -> bool {
687 matches!(*self, NameBindingKind::Import { .. })
691 struct PrivacyError<'a> {
693 binding: &'a NameBinding<'a>,
697 struct UseError<'a> {
698 err: DiagnosticBuilder<'a>,
699 /// Candidates which user could `use` to access the missing type.
700 candidates: Vec<ImportSuggestion>,
701 /// The `DefId` of the module to place the use-statements in.
703 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
705 /// Extra free-form suggestion.
706 suggestion: Option<(Span, &'static str, String, Applicability)>,
709 #[derive(Clone, Copy, PartialEq, Debug)]
714 MacroRulesVsModularized,
722 fn descr(self) -> &'static str {
724 AmbiguityKind::Import => "name vs any other name during import resolution",
725 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
726 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
727 AmbiguityKind::MacroRulesVsModularized => {
728 "`macro_rules` vs non-`macro_rules` from other module"
730 AmbiguityKind::GlobVsOuter => {
731 "glob import vs any other name from outer scope during import/macro resolution"
733 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
734 AmbiguityKind::GlobVsExpanded => {
735 "glob import vs macro-expanded name in the same \
736 module during import/macro resolution"
738 AmbiguityKind::MoreExpandedVsOuter => {
739 "macro-expanded name vs less macro-expanded name \
740 from outer scope during import/macro resolution"
746 /// Miscellaneous bits of metadata for better ambiguity error reporting.
747 #[derive(Clone, Copy, PartialEq)]
748 enum AmbiguityErrorMisc {
755 struct AmbiguityError<'a> {
758 b1: &'a NameBinding<'a>,
759 b2: &'a NameBinding<'a>,
760 misc1: AmbiguityErrorMisc,
761 misc2: AmbiguityErrorMisc,
764 impl<'a> NameBinding<'a> {
765 fn module(&self) -> Option<Module<'a>> {
767 NameBindingKind::Module(module) => Some(module),
768 NameBindingKind::Import { binding, .. } => binding.module(),
773 fn res(&self) -> Res {
775 NameBindingKind::Res(res, _) => res,
776 NameBindingKind::Module(module) => module.res().unwrap(),
777 NameBindingKind::Import { binding, .. } => binding.res(),
781 fn is_ambiguity(&self) -> bool {
782 self.ambiguity.is_some()
784 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
789 fn is_possibly_imported_variant(&self) -> bool {
791 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
792 NameBindingKind::Res(
793 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
796 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
800 fn is_extern_crate(&self) -> bool {
802 NameBindingKind::Import {
803 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
806 NameBindingKind::Module(&ModuleData {
807 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
809 }) => def_id.index == CRATE_DEF_INDEX,
814 fn is_import(&self) -> bool {
815 matches!(self.kind, NameBindingKind::Import { .. })
818 fn is_glob_import(&self) -> bool {
820 NameBindingKind::Import { import, .. } => import.is_glob(),
825 fn is_importable(&self) -> bool {
828 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
832 fn is_macro_def(&self) -> bool {
833 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
836 fn macro_kind(&self) -> Option<MacroKind> {
837 self.res().macro_kind()
840 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
841 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
842 // Then this function returns `true` if `self` may emerge from a macro *after* that
843 // in some later round and screw up our previously found resolution.
844 // See more detailed explanation in
845 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
848 invoc_parent_expansion: LocalExpnId,
849 binding: &NameBinding<'_>,
851 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
852 // Expansions are partially ordered, so "may appear after" is an inversion of
853 // "certainly appears before or simultaneously" and includes unordered cases.
854 let self_parent_expansion = self.expansion;
855 let other_parent_expansion = binding.expansion;
856 let certainly_before_other_or_simultaneously =
857 other_parent_expansion.is_descendant_of(self_parent_expansion);
858 let certainly_before_invoc_or_simultaneously =
859 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
860 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
864 #[derive(Debug, Default, Clone)]
865 pub struct ExternPreludeEntry<'a> {
866 extern_crate_item: Option<&'a NameBinding<'a>>,
867 pub introduced_by_item: bool,
870 /// Used for better errors for E0773
871 enum BuiltinMacroState {
872 NotYetSeen(SyntaxExtensionKind),
877 resolutions: DeriveResolutions,
878 helper_attrs: Vec<(usize, Ident)>,
879 has_derive_copy: bool,
882 /// The main resolver class.
884 /// This is the visitor that walks the whole crate.
885 pub struct Resolver<'a> {
886 session: &'a Session,
888 definitions: Definitions,
890 graph_root: Module<'a>,
892 prelude: Option<Module<'a>>,
893 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
895 /// N.B., this is used only for better diagnostics, not name resolution itself.
896 has_self: FxHashSet<DefId>,
898 /// Names of fields of an item `DefId` accessible with dot syntax.
899 /// Used for hints during error reporting.
900 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
902 /// All imports known to succeed or fail.
903 determined_imports: Vec<&'a Import<'a>>,
905 /// All non-determined imports.
906 indeterminate_imports: Vec<&'a Import<'a>>,
908 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
909 /// We are resolving a last import segment during import validation.
910 last_import_segment: bool,
911 /// This binding should be ignored during in-module resolution, so that we don't get
912 /// "self-confirming" import resolutions during import validation.
913 unusable_binding: Option<&'a NameBinding<'a>>,
915 // Spans for local variables found during pattern resolution.
916 // Used for suggestions during error reporting.
917 pat_span_map: NodeMap<Span>,
919 /// Resolutions for nodes that have a single resolution.
920 partial_res_map: NodeMap<PartialRes>,
921 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
922 import_res_map: NodeMap<PerNS<Option<Res>>>,
923 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
924 label_res_map: NodeMap<NodeId>,
926 /// `CrateNum` resolutions of `extern crate` items.
927 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
928 export_map: ExportMap,
929 trait_map: Option<NodeMap<Vec<TraitCandidate>>>,
931 /// A map from nodes to anonymous modules.
932 /// Anonymous modules are pseudo-modules that are implicitly created around items
933 /// contained within blocks.
935 /// For example, if we have this:
943 /// There will be an anonymous module created around `g` with the ID of the
944 /// entry block for `f`.
945 block_map: NodeMap<Module<'a>>,
946 /// A fake module that contains no definition and no prelude. Used so that
947 /// some AST passes can generate identifiers that only resolve to local or
949 empty_module: Module<'a>,
950 module_map: FxHashMap<DefId, Module<'a>>,
951 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
952 underscore_disambiguator: u32,
954 /// Maps glob imports to the names of items actually imported.
955 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
956 /// Visibilities in "lowered" form, for all entities that have them.
957 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
958 used_imports: FxHashSet<NodeId>,
959 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
960 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
962 /// Privacy errors are delayed until the end in order to deduplicate them.
963 privacy_errors: Vec<PrivacyError<'a>>,
964 /// Ambiguity errors are delayed for deduplication.
965 ambiguity_errors: Vec<AmbiguityError<'a>>,
966 /// `use` injections are delayed for better placement and deduplication.
967 use_injections: Vec<UseError<'a>>,
968 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
969 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
971 arenas: &'a ResolverArenas<'a>,
972 dummy_binding: &'a NameBinding<'a>,
974 crate_loader: CrateLoader<'a>,
975 macro_names: FxHashSet<Ident>,
976 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
977 registered_attrs: FxHashSet<Ident>,
978 registered_tools: FxHashSet<Ident>,
979 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
980 all_macros: FxHashMap<Symbol, Res>,
981 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
982 dummy_ext_bang: Lrc<SyntaxExtension>,
983 dummy_ext_derive: Lrc<SyntaxExtension>,
984 non_macro_attr: Lrc<SyntaxExtension>,
985 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
986 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
987 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
988 proc_macro_stubs: FxHashSet<LocalDefId>,
989 /// Traces collected during macro resolution and validated when it's complete.
990 single_segment_macro_resolutions:
991 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
992 multi_segment_macro_resolutions:
993 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
994 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
995 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
996 /// Derive macros cannot modify the item themselves and have to store the markers in the global
997 /// context, so they attach the markers to derive container IDs using this resolver table.
998 containers_deriving_copy: FxHashSet<LocalExpnId>,
999 /// Parent scopes in which the macros were invoked.
1000 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
1001 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
1002 /// `macro_rules` scopes *produced* by expanding the macro invocations,
1003 /// include all the `macro_rules` items and other invocations generated by them.
1004 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
1005 /// Helper attributes that are in scope for the given expansion.
1006 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
1007 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
1008 /// with the given `ExpnId`.
1009 derive_data: FxHashMap<LocalExpnId, DeriveData>,
1011 /// Avoid duplicated errors for "name already defined".
1012 name_already_seen: FxHashMap<Symbol, Span>,
1014 potentially_unused_imports: Vec<&'a Import<'a>>,
1016 /// Table for mapping struct IDs into struct constructor IDs,
1017 /// it's not used during normal resolution, only for better error reporting.
1018 /// Also includes of list of each fields visibility
1019 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1021 /// Features enabled for this crate.
1022 active_features: FxHashSet<Symbol>,
1024 lint_buffer: LintBuffer,
1026 next_node_id: NodeId,
1028 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1029 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1031 /// Indices of unnamed struct or variant fields with unresolved attributes.
1032 placeholder_field_indices: FxHashMap<NodeId, usize>,
1033 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1034 /// we know what parent node that fragment should be attached to thanks to this table,
1035 /// and how the `impl Trait` fragments were introduced.
1036 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1038 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1039 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1040 /// FIXME: Replace with a more general AST map (together with some other fields).
1041 trait_impl_items: FxHashSet<LocalDefId>,
1043 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1044 /// Amount of lifetime parameters for each item in the crate.
1045 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1047 main_def: Option<MainDefinition>,
1048 trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
1049 /// A list of proc macro LocalDefIds, written out in the order in which
1050 /// they are declared in the static array generated by proc_macro_harness.
1051 proc_macros: Vec<NodeId>,
1052 confused_type_with_std_module: FxHashMap<Span, Span>,
1055 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1057 pub struct ResolverArenas<'a> {
1058 modules: TypedArena<ModuleData<'a>>,
1059 local_modules: RefCell<Vec<Module<'a>>>,
1060 imports: TypedArena<Import<'a>>,
1061 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1062 ast_paths: TypedArena<ast::Path>,
1063 dropless: DroplessArena,
1066 impl<'a> ResolverArenas<'a> {
1069 parent: Option<Module<'a>>,
1073 no_implicit_prelude: bool,
1076 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1077 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1078 self.local_modules.borrow_mut().push(module);
1082 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1083 self.local_modules.borrow()
1085 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1086 self.dropless.alloc(name_binding)
1088 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1089 self.imports.alloc(import)
1091 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1092 self.name_resolutions.alloc(Default::default())
1094 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1095 PtrKey(self.dropless.alloc(Cell::new(scope)))
1097 fn alloc_macro_rules_binding(
1099 binding: MacroRulesBinding<'a>,
1100 ) -> &'a MacroRulesBinding<'a> {
1101 self.dropless.alloc(binding)
1103 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1104 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1106 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1107 self.dropless.alloc_from_iter(spans)
1111 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1112 fn as_mut(&mut self) -> &mut Resolver<'a> {
1117 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1118 fn parent(self, id: DefId) -> Option<DefId> {
1119 match id.as_local() {
1120 Some(id) => self.definitions.def_key(id).parent,
1121 None => self.cstore().def_key(id).parent,
1123 .map(|index| DefId { index, ..id })
1127 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1128 /// the resolver is no longer needed as all the relevant information is inline.
1129 impl ResolverAstLowering for Resolver<'_> {
1130 fn def_key(&mut self, id: DefId) -> DefKey {
1131 if let Some(id) = id.as_local() {
1132 self.definitions().def_key(id)
1134 self.cstore().def_key(id)
1139 fn def_span(&self, id: LocalDefId) -> Span {
1140 self.definitions.def_span(id)
1143 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1144 if let Some(def_id) = def_id.as_local() {
1145 self.item_generics_num_lifetimes[&def_id]
1147 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1151 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1152 self.legacy_const_generic_args(expr)
1155 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1156 self.partial_res_map.get(&id).cloned()
1159 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1160 self.import_res_map.get(&id).cloned().unwrap_or_default()
1163 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1164 self.label_res_map.get(&id).cloned()
1167 fn definitions(&mut self) -> &mut Definitions {
1168 &mut self.definitions
1171 fn lint_buffer(&mut self) -> &mut LintBuffer {
1172 &mut self.lint_buffer
1175 fn next_node_id(&mut self) -> NodeId {
1179 fn take_trait_map(&mut self) -> NodeMap<Vec<TraitCandidate>> {
1180 std::mem::replace(&mut self.trait_map, None).unwrap()
1183 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1184 self.node_id_to_def_id.get(&node).copied()
1187 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1188 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1191 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1192 match def_id.as_local() {
1193 Some(def_id) => self.definitions.def_path_hash(def_id),
1194 None => self.cstore().def_path_hash(def_id),
1198 /// Adds a definition with a parent definition.
1202 node_id: ast::NodeId,
1208 !self.node_id_to_def_id.contains_key(&node_id),
1209 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1212 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1215 // Find the next free disambiguator for this key.
1216 let next_disambiguator = &mut self.next_disambiguator;
1217 let next_disambiguator = |parent, data| {
1218 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1219 let disambiguator = *next_disamb;
1220 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1224 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1226 // Some things for which we allocate `LocalDefId`s don't correspond to
1227 // anything in the AST, so they don't have a `NodeId`. For these cases
1228 // we don't need a mapping from `NodeId` to `LocalDefId`.
1229 if node_id != ast::DUMMY_NODE_ID {
1230 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1231 self.node_id_to_def_id.insert(node_id, def_id);
1233 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1239 struct ExpandHasher<'a, 'b> {
1240 source_map: CachingSourceMapView<'a>,
1241 resolver: &'a Resolver<'b>,
1244 impl<'a, 'b> rustc_span::HashStableContext for ExpandHasher<'a, 'b> {
1246 fn hash_spans(&self) -> bool {
1251 fn def_span(&self, id: LocalDefId) -> Span {
1252 self.resolver.def_span(id)
1256 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1257 self.resolver.def_path_hash(def_id)
1261 fn span_data_to_lines_and_cols(
1263 span: &rustc_span::SpanData,
1264 ) -> Option<(Lrc<rustc_span::SourceFile>, usize, rustc_span::BytePos, usize, rustc_span::BytePos)>
1266 self.source_map.span_data_to_lines_and_cols(span)
1270 impl<'a> Resolver<'a> {
1272 session: &'a Session,
1275 metadata_loader: Box<MetadataLoaderDyn>,
1276 arenas: &'a ResolverArenas<'a>,
1278 let root_def_id = CRATE_DEF_ID.to_def_id();
1279 let graph_root = arenas.new_module(
1281 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1284 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1286 let empty_module = arenas.new_module(
1288 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1293 let mut module_map = FxHashMap::default();
1294 module_map.insert(root_def_id, graph_root);
1296 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1297 let root = definitions.get_root_def();
1299 let mut visibilities = FxHashMap::default();
1300 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1302 let mut def_id_to_node_id = IndexVec::default();
1303 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1304 let mut node_id_to_def_id = FxHashMap::default();
1305 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1307 let mut invocation_parents = FxHashMap::default();
1308 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1310 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1314 .filter(|(_, entry)| entry.add_prelude)
1315 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1318 if !session.contains_name(&krate.attrs, sym::no_core) {
1319 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1320 if !session.contains_name(&krate.attrs, sym::no_std) {
1321 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1325 let (registered_attrs, registered_tools) =
1326 macros::registered_attrs_and_tools(session, &krate.attrs);
1328 let features = session.features_untracked();
1330 let mut resolver = Resolver {
1335 // The outermost module has def ID 0; this is not reflected in the
1341 has_self: FxHashSet::default(),
1342 field_names: FxHashMap::default(),
1344 determined_imports: Vec::new(),
1345 indeterminate_imports: Vec::new(),
1347 last_import_segment: false,
1348 unusable_binding: None,
1350 pat_span_map: Default::default(),
1351 partial_res_map: Default::default(),
1352 import_res_map: Default::default(),
1353 label_res_map: Default::default(),
1354 extern_crate_map: Default::default(),
1355 export_map: FxHashMap::default(),
1356 trait_map: Some(NodeMap::default()),
1357 underscore_disambiguator: 0,
1360 block_map: Default::default(),
1361 binding_parent_modules: FxHashMap::default(),
1362 ast_transform_scopes: FxHashMap::default(),
1364 glob_map: Default::default(),
1366 used_imports: FxHashSet::default(),
1367 maybe_unused_trait_imports: Default::default(),
1368 maybe_unused_extern_crates: Vec::new(),
1370 privacy_errors: Vec::new(),
1371 ambiguity_errors: Vec::new(),
1372 use_injections: Vec::new(),
1373 macro_expanded_macro_export_errors: BTreeSet::new(),
1376 dummy_binding: arenas.alloc_name_binding(NameBinding {
1377 kind: NameBindingKind::Res(Res::Err, false),
1379 expansion: LocalExpnId::ROOT,
1381 vis: ty::Visibility::Public,
1384 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1385 macro_names: FxHashSet::default(),
1386 builtin_macros: Default::default(),
1389 macro_use_prelude: FxHashMap::default(),
1390 all_macros: FxHashMap::default(),
1391 macro_map: FxHashMap::default(),
1392 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1393 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1394 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1395 invocation_parent_scopes: Default::default(),
1396 output_macro_rules_scopes: Default::default(),
1397 helper_attrs: Default::default(),
1398 derive_data: Default::default(),
1399 local_macro_def_scopes: FxHashMap::default(),
1400 name_already_seen: FxHashMap::default(),
1401 potentially_unused_imports: Vec::new(),
1402 struct_constructors: Default::default(),
1403 unused_macros: Default::default(),
1404 proc_macro_stubs: Default::default(),
1405 single_segment_macro_resolutions: Default::default(),
1406 multi_segment_macro_resolutions: Default::default(),
1407 builtin_attrs: Default::default(),
1408 containers_deriving_copy: Default::default(),
1409 active_features: features
1410 .declared_lib_features
1412 .map(|(feat, ..)| *feat)
1413 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1415 lint_buffer: LintBuffer::default(),
1416 next_node_id: NodeId::from_u32(1),
1419 placeholder_field_indices: Default::default(),
1421 next_disambiguator: Default::default(),
1422 trait_impl_items: Default::default(),
1423 legacy_const_generic_args: Default::default(),
1424 item_generics_num_lifetimes: Default::default(),
1425 main_def: Default::default(),
1426 trait_impls: Default::default(),
1427 proc_macros: Default::default(),
1428 confused_type_with_std_module: Default::default(),
1431 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1432 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1437 fn create_stable_hashing_context(&self) -> ExpandHasher<'_, 'a> {
1439 source_map: CachingSourceMapView::new(self.session.source_map()),
1444 pub fn next_node_id(&mut self) -> NodeId {
1449 .expect("input too large; ran out of NodeIds");
1450 self.next_node_id = ast::NodeId::from_usize(next);
1454 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1455 &mut self.lint_buffer
1458 pub fn arenas() -> ResolverArenas<'a> {
1462 pub fn into_outputs(self) -> ResolverOutputs {
1463 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1464 let definitions = self.definitions;
1465 let visibilities = self.visibilities;
1466 let extern_crate_map = self.extern_crate_map;
1467 let export_map = self.export_map;
1468 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1469 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1470 let glob_map = self.glob_map;
1471 let main_def = self.main_def;
1472 let confused_type_with_std_module = self.confused_type_with_std_module;
1475 cstore: Box::new(self.crate_loader.into_cstore()),
1480 maybe_unused_trait_imports,
1481 maybe_unused_extern_crates,
1482 extern_prelude: self
1485 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1488 trait_impls: self.trait_impls,
1490 confused_type_with_std_module,
1494 pub fn clone_outputs(&self) -> ResolverOutputs {
1495 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1497 definitions: self.definitions.clone(),
1498 cstore: Box::new(self.cstore().clone()),
1499 visibilities: self.visibilities.clone(),
1500 extern_crate_map: self.extern_crate_map.clone(),
1501 export_map: self.export_map.clone(),
1502 glob_map: self.glob_map.clone(),
1503 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1504 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1505 extern_prelude: self
1508 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1510 main_def: self.main_def,
1511 trait_impls: self.trait_impls.clone(),
1513 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1517 pub fn cstore(&self) -> &CStore {
1518 self.crate_loader.cstore()
1521 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1523 MacroKind::Bang => self.dummy_ext_bang.clone(),
1524 MacroKind::Derive => self.dummy_ext_derive.clone(),
1525 MacroKind::Attr => self.non_macro_attr.clone(),
1529 /// Runs the function on each namespace.
1530 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1536 fn is_builtin_macro(&mut self, res: Res) -> bool {
1537 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1540 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1542 match ctxt.outer_expn_data().macro_def_id {
1543 Some(def_id) => return def_id,
1544 None => ctxt.remove_mark(),
1549 /// Entry point to crate resolution.
1550 pub fn resolve_crate(&mut self, krate: &Crate) {
1551 self.session.time("resolve_crate", || {
1552 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1553 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1554 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1555 self.session.time("resolve_main", || self.resolve_main());
1556 self.session.time("resolve_check_unused", || self.check_unused(krate));
1557 self.session.time("resolve_report_errors", || self.report_errors(krate));
1558 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1562 pub fn traits_in_scope(
1564 current_trait: Option<Module<'a>>,
1565 parent_scope: &ParentScope<'a>,
1566 ctxt: SyntaxContext,
1567 assoc_item: Option<(Symbol, Namespace)>,
1568 ) -> Vec<TraitCandidate> {
1569 let mut found_traits = Vec::new();
1571 if let Some(module) = current_trait {
1572 if self.trait_may_have_item(Some(module), assoc_item) {
1573 let def_id = module.def_id().unwrap();
1574 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1578 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1580 Scope::Module(module, _) => {
1581 this.traits_in_module(module, assoc_item, &mut found_traits);
1583 Scope::StdLibPrelude => {
1584 if let Some(module) = this.prelude {
1585 this.traits_in_module(module, assoc_item, &mut found_traits);
1588 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1589 _ => unreachable!(),
1597 fn traits_in_module(
1600 assoc_item: Option<(Symbol, Namespace)>,
1601 found_traits: &mut Vec<TraitCandidate>,
1603 module.ensure_traits(self);
1604 let traits = module.traits.borrow();
1605 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1606 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1607 let def_id = trait_binding.res().def_id();
1608 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1609 found_traits.push(TraitCandidate { def_id, import_ids });
1614 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1615 // associated item with the given name and namespace (if specified). This is a conservative
1616 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1617 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1618 // associated items.
1619 fn trait_may_have_item(
1621 trait_module: Option<Module<'a>>,
1622 assoc_item: Option<(Symbol, Namespace)>,
1624 match (trait_module, assoc_item) {
1625 (Some(trait_module), Some((name, ns))) => {
1626 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1627 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1628 assoc_ns == ns && assoc_ident.name == name
1635 fn find_transitive_imports(
1637 mut kind: &NameBindingKind<'_>,
1639 ) -> SmallVec<[LocalDefId; 1]> {
1640 let mut import_ids = smallvec![];
1641 while let NameBindingKind::Import { import, binding, .. } = kind {
1642 let id = self.local_def_id(import.id);
1643 self.maybe_unused_trait_imports.insert(id);
1644 self.add_to_glob_map(&import, trait_name);
1645 import_ids.push(id);
1646 kind = &binding.kind;
1651 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1652 let ident = ident.normalize_to_macros_2_0();
1653 let disambiguator = if ident.name == kw::Underscore {
1654 self.underscore_disambiguator += 1;
1655 self.underscore_disambiguator
1659 BindingKey { ident, ns, disambiguator }
1662 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1663 if module.populate_on_access.get() {
1664 module.populate_on_access.set(false);
1665 self.build_reduced_graph_external(module);
1667 &module.lazy_resolutions
1674 ) -> &'a RefCell<NameResolution<'a>> {
1676 .resolutions(module)
1679 .or_insert_with(|| self.arenas.alloc_name_resolution())
1685 used_binding: &'a NameBinding<'a>,
1686 is_lexical_scope: bool,
1688 if let Some((b2, kind)) = used_binding.ambiguity {
1689 self.ambiguity_errors.push(AmbiguityError {
1694 misc1: AmbiguityErrorMisc::None,
1695 misc2: AmbiguityErrorMisc::None,
1698 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1699 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1700 // but not introduce it, as used if they are accessed from lexical scope.
1701 if is_lexical_scope {
1702 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1703 if let Some(crate_item) = entry.extern_crate_item {
1704 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1711 import.used.set(true);
1712 self.used_imports.insert(import.id);
1713 self.add_to_glob_map(&import, ident);
1714 self.record_use(ident, binding, false);
1719 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1720 if import.is_glob() {
1721 let def_id = self.local_def_id(import.id);
1722 self.glob_map.entry(def_id).or_default().insert(ident.name);
1726 /// A generic scope visitor.
1727 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1728 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1731 scope_set: ScopeSet<'a>,
1732 parent_scope: &ParentScope<'a>,
1733 ctxt: SyntaxContext,
1734 mut visitor: impl FnMut(
1737 /*use_prelude*/ bool,
1741 // General principles:
1742 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1743 // built into the language or standard library. This way we can add new names into the
1744 // language or standard library without breaking user code.
1745 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1746 // Places to search (in order of decreasing priority):
1748 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1749 // (open set, not controlled).
1750 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1751 // (open, not controlled).
1752 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1753 // 4. Tool modules (closed, controlled right now, but not in the future).
1754 // 5. Standard library prelude (de-facto closed, controlled).
1755 // 6. Language prelude (closed, controlled).
1757 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1758 // (open set, not controlled).
1759 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1760 // (open, not controlled).
1761 // 3. Standard library prelude (de-facto closed, controlled).
1763 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1764 // are currently reported as errors. They should be higher in priority than preludes
1765 // and probably even names in modules according to the "general principles" above. They
1766 // also should be subject to restricted shadowing because are effectively produced by
1767 // derives (you need to resolve the derive first to add helpers into scope), but they
1768 // should be available before the derive is expanded for compatibility.
1769 // It's mess in general, so we are being conservative for now.
1770 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1771 // priority than prelude macros, but create ambiguities with macros in modules.
1772 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1773 // (open, not controlled). Have higher priority than prelude macros, but create
1774 // ambiguities with `macro_rules`.
1775 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1776 // 4a. User-defined prelude from macro-use
1777 // (open, the open part is from macro expansions, not controlled).
1778 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1779 // 4c. Standard library prelude (de-facto closed, controlled).
1780 // 6. Language prelude: builtin attributes (closed, controlled).
1782 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1783 let (ns, macro_kind, is_absolute_path) = match scope_set {
1784 ScopeSet::All(ns, _) => (ns, None, false),
1785 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1786 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1787 ScopeSet::Late(ns, ..) => (ns, None, false),
1789 let module = match scope_set {
1790 // Start with the specified module.
1791 ScopeSet::Late(_, module, _) => module,
1792 // Jump out of trait or enum modules, they do not act as scopes.
1793 _ => parent_scope.module.nearest_item_scope(),
1795 let mut scope = match ns {
1796 _ if is_absolute_path => Scope::CrateRoot,
1797 TypeNS | ValueNS => Scope::Module(module, None),
1798 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1800 let mut ctxt = ctxt.normalize_to_macros_2_0();
1801 let mut use_prelude = !module.no_implicit_prelude;
1804 let visit = match scope {
1805 // Derive helpers are not in scope when resolving derives in the same container.
1806 Scope::DeriveHelpers(expn_id) => {
1807 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1809 Scope::DeriveHelpersCompat => true,
1810 Scope::MacroRules(macro_rules_scope) => {
1811 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1812 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1813 // As another consequence of this optimization visitors never observe invocation
1814 // scopes for macros that were already expanded.
1815 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1816 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1817 macro_rules_scope.set(next_scope.get());
1824 Scope::CrateRoot => true,
1825 Scope::Module(..) => true,
1826 Scope::RegisteredAttrs => use_prelude,
1827 Scope::MacroUsePrelude => use_prelude || rust_2015,
1828 Scope::BuiltinAttrs => true,
1829 Scope::ExternPrelude => use_prelude || is_absolute_path,
1830 Scope::ToolPrelude => use_prelude,
1831 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1832 Scope::BuiltinTypes => true,
1836 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1837 return break_result;
1841 scope = match scope {
1842 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1843 Scope::DeriveHelpers(expn_id) => {
1844 // Derive helpers are not visible to code generated by bang or derive macros.
1845 let expn_data = expn_id.expn_data();
1846 match expn_data.kind {
1848 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1849 Scope::DeriveHelpersCompat
1851 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1854 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1855 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1856 MacroRulesScope::Binding(binding) => {
1857 Scope::MacroRules(binding.parent_macro_rules_scope)
1859 MacroRulesScope::Invocation(invoc_id) => {
1860 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1862 MacroRulesScope::Empty => Scope::Module(module, None),
1864 Scope::CrateRoot => match ns {
1866 ctxt.adjust(ExpnId::root());
1867 Scope::ExternPrelude
1869 ValueNS | MacroNS => break,
1871 Scope::Module(module, prev_lint_id) => {
1872 use_prelude = !module.no_implicit_prelude;
1873 let derive_fallback_lint_id = match scope_set {
1874 ScopeSet::Late(.., lint_id) => lint_id,
1877 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1878 Some((parent_module, lint_id)) => {
1879 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1882 ctxt.adjust(ExpnId::root());
1884 TypeNS => Scope::ExternPrelude,
1885 ValueNS => Scope::StdLibPrelude,
1886 MacroNS => Scope::RegisteredAttrs,
1891 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1892 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1893 Scope::BuiltinAttrs => break, // nowhere else to search
1894 Scope::ExternPrelude if is_absolute_path => break,
1895 Scope::ExternPrelude => Scope::ToolPrelude,
1896 Scope::ToolPrelude => Scope::StdLibPrelude,
1897 Scope::StdLibPrelude => match ns {
1898 TypeNS => Scope::BuiltinTypes,
1899 ValueNS => break, // nowhere else to search
1900 MacroNS => Scope::BuiltinAttrs,
1902 Scope::BuiltinTypes => break, // nowhere else to search
1909 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1910 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1911 /// `ident` in the first scope that defines it (or None if no scopes define it).
1913 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1914 /// the items are defined in the block. For example,
1917 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1920 /// g(); // This resolves to the local variable `g` since it shadows the item.
1924 /// Invariant: This must only be called during main resolution, not during
1925 /// import resolution.
1926 fn resolve_ident_in_lexical_scope(
1930 parent_scope: &ParentScope<'a>,
1931 record_used_id: Option<NodeId>,
1934 ) -> Option<LexicalScopeBinding<'a>> {
1935 assert!(ns == TypeNS || ns == ValueNS);
1936 let orig_ident = ident;
1937 if ident.name == kw::Empty {
1938 return Some(LexicalScopeBinding::Res(Res::Err));
1940 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1941 // FIXME(jseyfried) improve `Self` hygiene
1942 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1943 (empty_span, empty_span)
1944 } else if ns == TypeNS {
1945 let normalized_span = ident.span.normalize_to_macros_2_0();
1946 (normalized_span, normalized_span)
1948 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1950 ident.span = general_span;
1951 let normalized_ident = Ident { span: normalized_span, ..ident };
1953 // Walk backwards up the ribs in scope.
1954 let record_used = record_used_id.is_some();
1955 let mut module = self.graph_root;
1956 for i in (0..ribs.len()).rev() {
1957 debug!("walk rib\n{:?}", ribs[i].bindings);
1958 // Use the rib kind to determine whether we are resolving parameters
1959 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1960 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1961 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1963 // The ident resolves to a type parameter or local variable.
1964 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1970 *original_rib_ident_def,
1975 module = match ribs[i].kind {
1976 ModuleRibKind(module) => module,
1977 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1978 // If an invocation of this macro created `ident`, give up on `ident`
1979 // and switch to `ident`'s source from the macro definition.
1980 ident.span.remove_mark();
1987 ModuleKind::Block(..) => {} // We can see through blocks
1991 let item = self.resolve_ident_in_module_unadjusted(
1992 ModuleOrUniformRoot::Module(module),
1999 if let Ok(binding) = item {
2000 // The ident resolves to an item.
2001 return Some(LexicalScopeBinding::Item(binding));
2004 self.early_resolve_ident_in_lexical_scope(
2006 ScopeSet::Late(ns, module, record_used_id),
2013 .map(LexicalScopeBinding::Item)
2016 fn hygienic_lexical_parent(
2019 ctxt: &mut SyntaxContext,
2020 derive_fallback_lint_id: Option<NodeId>,
2021 ) -> Option<(Module<'a>, Option<NodeId>)> {
2022 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2023 return Some((self.expn_def_scope(ctxt.remove_mark()), None));
2026 if let ModuleKind::Block(..) = module.kind {
2027 return Some((module.parent.unwrap().nearest_item_scope(), None));
2030 // We need to support the next case under a deprecation warning
2033 // ---- begin: this comes from a proc macro derive
2034 // mod implementation_details {
2035 // // Note that `MyStruct` is not in scope here.
2036 // impl SomeTrait for MyStruct { ... }
2040 // So we have to fall back to the module's parent during lexical resolution in this case.
2041 if derive_fallback_lint_id.is_some() {
2042 if let Some(parent) = module.parent {
2043 // Inner module is inside the macro, parent module is outside of the macro.
2044 if module.expansion != parent.expansion
2045 && module.expansion.is_descendant_of(parent.expansion)
2047 // The macro is a proc macro derive
2048 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2049 let ext = self.get_macro_by_def_id(def_id);
2050 if ext.builtin_name.is_none()
2051 && ext.macro_kind() == MacroKind::Derive
2052 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2054 return Some((parent, derive_fallback_lint_id));
2064 fn resolve_ident_in_module(
2066 module: ModuleOrUniformRoot<'a>,
2069 parent_scope: &ParentScope<'a>,
2072 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2073 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2074 .map_err(|(determinacy, _)| determinacy)
2077 fn resolve_ident_in_module_ext(
2079 module: ModuleOrUniformRoot<'a>,
2082 parent_scope: &ParentScope<'a>,
2085 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2086 let tmp_parent_scope;
2087 let mut adjusted_parent_scope = parent_scope;
2089 ModuleOrUniformRoot::Module(m) => {
2090 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2092 ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
2093 adjusted_parent_scope = &tmp_parent_scope;
2096 ModuleOrUniformRoot::ExternPrelude => {
2097 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2099 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2103 self.resolve_ident_in_module_unadjusted_ext(
2107 adjusted_parent_scope,
2114 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2115 debug!("resolve_crate_root({:?})", ident);
2116 let mut ctxt = ident.span.ctxt();
2117 let mark = if ident.name == kw::DollarCrate {
2118 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2119 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2120 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2121 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2122 // definitions actually produced by `macro` and `macro` definitions produced by
2123 // `macro_rules!`, but at least such configurations are not stable yet.
2124 ctxt = ctxt.normalize_to_macro_rules();
2126 "resolve_crate_root: marks={:?}",
2127 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2129 let mut iter = ctxt.marks().into_iter().rev().peekable();
2130 let mut result = None;
2131 // Find the last opaque mark from the end if it exists.
2132 while let Some(&(mark, transparency)) = iter.peek() {
2133 if transparency == Transparency::Opaque {
2134 result = Some(mark);
2141 "resolve_crate_root: found opaque mark {:?} {:?}",
2143 result.map(|r| r.expn_data())
2145 // Then find the last semi-transparent mark from the end if it exists.
2146 for (mark, transparency) in iter {
2147 if transparency == Transparency::SemiTransparent {
2148 result = Some(mark);
2154 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2156 result.map(|r| r.expn_data())
2160 debug!("resolve_crate_root: not DollarCrate");
2161 ctxt = ctxt.normalize_to_macros_2_0();
2162 ctxt.adjust(ExpnId::root())
2164 let module = match mark {
2165 Some(def) => self.expn_def_scope(def),
2168 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2171 return self.graph_root;
2175 .expect_module(module.def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id());
2177 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2186 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2187 let mut module = self.expect_module(module.nearest_parent_mod());
2188 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2189 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
2190 module = self.expect_module(parent.nearest_parent_mod());
2198 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2199 parent_scope: &ParentScope<'a>,
2202 crate_lint: CrateLint,
2203 ) -> PathResult<'a> {
2204 self.resolve_path_with_ribs(
2215 fn resolve_path_with_ribs(
2218 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2219 parent_scope: &ParentScope<'a>,
2222 crate_lint: CrateLint,
2223 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2224 ) -> PathResult<'a> {
2225 let mut module = None;
2226 let mut allow_super = true;
2227 let mut second_binding = None;
2230 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2231 path_span={:?}, crate_lint={:?})",
2232 path, opt_ns, record_used, path_span, crate_lint,
2235 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2236 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2237 let record_segment_res = |this: &mut Self, res| {
2239 if let Some(id) = id {
2240 if !this.partial_res_map.contains_key(&id) {
2241 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2242 this.record_partial_res(id, PartialRes::new(res));
2248 let is_last = i == path.len() - 1;
2249 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2250 let name = ident.name;
2252 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2255 if allow_super && name == kw::Super {
2256 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2257 let self_module = match i {
2258 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2260 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2264 if let Some(self_module) = self_module {
2265 if let Some(parent) = self_module.parent {
2266 module = Some(ModuleOrUniformRoot::Module(
2267 self.resolve_self(&mut ctxt, parent),
2272 let msg = "there are too many leading `super` keywords".to_string();
2273 return PathResult::Failed {
2277 is_error_from_last_segment: false,
2281 if name == kw::SelfLower {
2282 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2283 module = Some(ModuleOrUniformRoot::Module(
2284 self.resolve_self(&mut ctxt, parent_scope.module),
2288 if name == kw::PathRoot && ident.span.rust_2018() {
2289 module = Some(ModuleOrUniformRoot::ExternPrelude);
2292 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2293 // `::a::b` from 2015 macro on 2018 global edition
2294 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2297 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2298 // `::a::b`, `crate::a::b` or `$crate::a::b`
2299 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2305 // Report special messages for path segment keywords in wrong positions.
2306 if ident.is_path_segment_keyword() && i != 0 {
2307 let name_str = if name == kw::PathRoot {
2308 "crate root".to_string()
2310 format!("`{}`", name)
2312 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2313 format!("global paths cannot start with {}", name_str)
2315 format!("{} in paths can only be used in start position", name_str)
2317 return PathResult::Failed {
2321 is_error_from_last_segment: false,
2325 enum FindBindingResult<'a> {
2326 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2327 PathResult(PathResult<'a>),
2329 let find_binding_in_ns = |this: &mut Self, ns| {
2330 let binding = if let Some(module) = module {
2331 this.resolve_ident_in_module(
2339 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2340 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2341 this.early_resolve_ident_in_lexical_scope(
2350 let record_used_id = if record_used {
2351 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2355 match this.resolve_ident_in_lexical_scope(
2363 // we found a locally-imported or available item/module
2364 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2365 // we found a local variable or type param
2366 Some(LexicalScopeBinding::Res(res))
2367 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2369 record_segment_res(this, res);
2370 return FindBindingResult::PathResult(PathResult::NonModule(
2371 PartialRes::with_unresolved_segments(res, path.len() - 1),
2374 _ => Err(Determinacy::determined(record_used)),
2377 FindBindingResult::Binding(binding)
2379 let binding = match find_binding_in_ns(self, ns) {
2380 FindBindingResult::PathResult(x) => return x,
2381 FindBindingResult::Binding(binding) => binding,
2386 second_binding = Some(binding);
2388 let res = binding.res();
2389 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2390 if let Some(next_module) = binding.module() {
2391 module = Some(ModuleOrUniformRoot::Module(next_module));
2392 record_segment_res(self, res);
2393 } else if res == Res::ToolMod && i + 1 != path.len() {
2394 if binding.is_import() {
2398 "cannot use a tool module through an import",
2400 .span_note(binding.span, "the tool module imported here")
2403 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2404 return PathResult::NonModule(PartialRes::new(res));
2405 } else if res == Res::Err {
2406 return PathResult::NonModule(PartialRes::new(Res::Err));
2407 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2408 self.lint_if_path_starts_with_module(
2414 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2419 let label = format!(
2420 "`{}` is {} {}, not a module",
2426 return PathResult::Failed {
2430 is_error_from_last_segment: is_last,
2434 Err(Undetermined) => return PathResult::Indeterminate,
2435 Err(Determined) => {
2436 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2437 if opt_ns.is_some() && !module.is_normal() {
2438 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2439 module.res().unwrap(),
2444 let module_res = match module {
2445 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2448 let (label, suggestion) = if module_res == self.graph_root.res() {
2449 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2450 // Don't look up import candidates if this is a speculative resolve
2451 let mut candidates = if record_used {
2452 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2456 candidates.sort_by_cached_key(|c| {
2457 (c.path.segments.len(), pprust::path_to_string(&c.path))
2459 if let Some(candidate) = candidates.get(0) {
2461 String::from("unresolved import"),
2463 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2464 String::from("a similar path exists"),
2465 Applicability::MaybeIncorrect,
2468 } else if self.session.edition() == Edition::Edition2015 {
2469 (format!("maybe a missing crate `{}`?", ident), None)
2471 (format!("could not find `{}` in the crate root", ident), None)
2479 .map_or(false, |c| c.is_ascii_uppercase())
2481 // Check whether the name refers to an item in the value namespace.
2482 let suggestion = if ribs.is_some() {
2483 let match_span = match self.resolve_ident_in_lexical_scope(
2489 &ribs.unwrap()[ValueNS],
2491 // Name matches a local variable. For example:
2494 // let Foo: &str = "";
2495 // println!("{}", Foo::Bar); // Name refers to local
2496 // // variable `Foo`.
2499 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2500 Some(*self.pat_span_map.get(&id).unwrap())
2503 // Name matches item from a local name binding
2504 // created by `use` declaration. For example:
2506 // pub Foo: &str = "";
2510 // println!("{}", Foo::Bar); // Name refers to local
2511 // // binding `Foo`.
2514 Some(LexicalScopeBinding::Item(name_binding)) => {
2515 Some(name_binding.span)
2520 if let Some(span) = match_span {
2522 vec![(span, String::from(""))],
2523 format!("`{}` is defined here, but is not a type", ident),
2524 Applicability::MaybeIncorrect,
2533 (format!("use of undeclared type `{}`", ident), suggestion)
2535 (format!("use of undeclared crate or module `{}`", ident), None)
2538 let parent = path[i - 1].ident.name;
2539 let parent = match parent {
2540 // ::foo is mounted at the crate root for 2015, and is the extern
2541 // prelude for 2018+
2542 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2543 "the list of imported crates".to_owned()
2545 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2547 format!("`{}`", parent)
2551 let mut msg = format!("could not find `{}` in {}", ident, parent);
2552 if ns == TypeNS || ns == ValueNS {
2553 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2554 if let FindBindingResult::Binding(Ok(binding)) =
2555 find_binding_in_ns(self, ns_to_try)
2557 let mut found = |what| {
2559 "expected {}, found {} `{}` in {}",
2566 if binding.module().is_some() {
2569 match binding.res() {
2570 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2571 _ => found(ns_to_try.descr()),
2578 return PathResult::Failed {
2582 is_error_from_last_segment: is_last,
2588 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2590 PathResult::Module(match module {
2591 Some(module) => module,
2592 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2593 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2597 fn lint_if_path_starts_with_module(
2599 crate_lint: CrateLint,
2602 second_binding: Option<&NameBinding<'_>>,
2604 let (diag_id, diag_span) = match crate_lint {
2605 CrateLint::No => return,
2606 CrateLint::SimplePath(id) => (id, path_span),
2607 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2608 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2611 let first_name = match path.get(0) {
2612 // In the 2018 edition this lint is a hard error, so nothing to do
2613 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2617 // We're only interested in `use` paths which should start with
2618 // `{{root}}` currently.
2619 if first_name != kw::PathRoot {
2624 // If this import looks like `crate::...` it's already good
2625 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2626 // Otherwise go below to see if it's an extern crate
2628 // If the path has length one (and it's `PathRoot` most likely)
2629 // then we don't know whether we're gonna be importing a crate or an
2630 // item in our crate. Defer this lint to elsewhere
2634 // If the first element of our path was actually resolved to an
2635 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2636 // warning, this looks all good!
2637 if let Some(binding) = second_binding {
2638 if let NameBindingKind::Import { import, .. } = binding.kind {
2639 // Careful: we still want to rewrite paths from renamed extern crates.
2640 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2646 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2647 self.lint_buffer.buffer_lint_with_diagnostic(
2648 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2651 "absolute paths must start with `self`, `super`, \
2652 `crate`, or an external crate name in the 2018 edition",
2657 // Validate a local resolution (from ribs).
2658 fn validate_res_from_ribs(
2665 original_rib_ident_def: Ident,
2666 all_ribs: &[Rib<'a>],
2668 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2669 debug!("validate_res_from_ribs({:?})", res);
2670 let ribs = &all_ribs[rib_index + 1..];
2672 // An invalid forward use of a generic parameter from a previous default.
2673 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2675 let res_error = if rib_ident.name == kw::SelfUpper {
2676 ResolutionError::SelfInGenericParamDefault
2678 ResolutionError::ForwardDeclaredGenericParam
2680 self.report_error(span, res_error);
2682 assert_eq!(res, Res::Err);
2688 use ResolutionError::*;
2689 let mut res_err = None;
2694 | ClosureOrAsyncRibKind
2696 | MacroDefinition(..)
2697 | ForwardGenericParamBanRibKind => {
2698 // Nothing to do. Continue.
2700 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2701 // This was an attempt to access an upvar inside a
2702 // named function item. This is not allowed, so we
2705 // We don't immediately trigger a resolve error, because
2706 // we want certain other resolution errors (namely those
2707 // emitted for `ConstantItemRibKind` below) to take
2709 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2712 ConstantItemRibKind(_, item) => {
2713 // Still doesn't deal with upvars
2715 let (span, resolution_error) =
2716 if let Some((ident, constant_item_kind)) = item {
2717 let kind_str = match constant_item_kind {
2718 ConstantItemKind::Const => "const",
2719 ConstantItemKind::Static => "static",
2723 AttemptToUseNonConstantValueInConstant(
2724 ident, "let", kind_str,
2730 AttemptToUseNonConstantValueInConstant(
2731 original_rib_ident_def,
2737 self.report_error(span, resolution_error);
2741 ConstParamTyRibKind => {
2743 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2749 if let Some(res_err) = res_err {
2750 self.report_error(span, res_err);
2754 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2756 let has_generic_params: HasGenericParams = match rib.kind {
2758 | ClosureOrAsyncRibKind
2761 | MacroDefinition(..)
2762 | ForwardGenericParamBanRibKind => {
2763 // Nothing to do. Continue.
2767 ConstantItemRibKind(trivial, _) => {
2768 let features = self.session.features_untracked();
2769 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2770 if !(trivial || features.generic_const_exprs) {
2771 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2772 // we can't easily tell if it's generic at this stage, so we instead remember
2773 // this and then enforce the self type to be concrete later on.
2774 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2775 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2780 ResolutionError::ParamInNonTrivialAnonConst {
2781 name: rib_ident.name,
2787 self.session.delay_span_bug(span, CG_BUG_STR);
2795 // This was an attempt to use a type parameter outside its scope.
2796 ItemRibKind(has_generic_params) => has_generic_params,
2797 FnItemRibKind => HasGenericParams::Yes,
2798 ConstParamTyRibKind => {
2802 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2812 ResolutionError::GenericParamsFromOuterFunction(
2821 Res::Def(DefKind::ConstParam, _) => {
2822 let mut ribs = ribs.iter().peekable();
2823 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2824 // When declaring const parameters inside function signatures, the first rib
2825 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2826 // (spuriously) conflicting with the const param.
2831 let has_generic_params = match rib.kind {
2833 | ClosureOrAsyncRibKind
2836 | MacroDefinition(..)
2837 | ForwardGenericParamBanRibKind => continue,
2839 ConstantItemRibKind(trivial, _) => {
2840 let features = self.session.features_untracked();
2841 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2842 if !(trivial || features.generic_const_exprs) {
2846 ResolutionError::ParamInNonTrivialAnonConst {
2847 name: rib_ident.name,
2853 self.session.delay_span_bug(span, CG_BUG_STR);
2860 ItemRibKind(has_generic_params) => has_generic_params,
2861 FnItemRibKind => HasGenericParams::Yes,
2862 ConstParamTyRibKind => {
2866 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2873 // This was an attempt to use a const parameter outside its scope.
2877 ResolutionError::GenericParamsFromOuterFunction(
2891 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2892 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2893 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2894 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2898 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2899 debug!("(recording pat) recording {:?} for {:?}", node, span);
2900 self.pat_span_map.insert(node, span);
2903 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2904 vis.is_accessible_from(module.nearest_parent_mod(), self)
2907 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2908 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2909 if !ptr::eq(module, old_module) {
2910 span_bug!(binding.span, "parent module is reset for binding");
2915 fn disambiguate_macro_rules_vs_modularized(
2917 macro_rules: &'a NameBinding<'a>,
2918 modularized: &'a NameBinding<'a>,
2920 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2921 // is disambiguated to mitigate regressions from macro modularization.
2922 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2924 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2925 self.binding_parent_modules.get(&PtrKey(modularized)),
2927 (Some(macro_rules), Some(modularized)) => {
2928 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
2929 && modularized.is_ancestor_of(macro_rules)
2935 fn report_errors(&mut self, krate: &Crate) {
2936 self.report_with_use_injections(krate);
2938 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2939 let msg = "macro-expanded `macro_export` macros from the current crate \
2940 cannot be referred to by absolute paths";
2941 self.lint_buffer.buffer_lint_with_diagnostic(
2942 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2946 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2950 for ambiguity_error in &self.ambiguity_errors {
2951 self.report_ambiguity_error(ambiguity_error);
2954 let mut reported_spans = FxHashSet::default();
2955 for error in &self.privacy_errors {
2956 if reported_spans.insert(error.dedup_span) {
2957 self.report_privacy_error(error);
2962 fn report_with_use_injections(&mut self, krate: &Crate) {
2963 for UseError { mut err, candidates, def_id, instead, suggestion } in
2964 self.use_injections.drain(..)
2966 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2967 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2971 if !candidates.is_empty() {
2972 diagnostics::show_candidates(
2981 } else if let Some((span, msg, sugg, appl)) = suggestion {
2982 err.span_suggestion(span, msg, sugg, appl);
2988 fn report_conflict<'b>(
2993 new_binding: &NameBinding<'b>,
2994 old_binding: &NameBinding<'b>,
2996 // Error on the second of two conflicting names
2997 if old_binding.span.lo() > new_binding.span.lo() {
2998 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3001 let container = match parent.kind {
3002 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
3003 ModuleKind::Block(..) => "block",
3006 let old_noun = match old_binding.is_import() {
3008 false => "definition",
3011 let new_participle = match new_binding.is_import() {
3017 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3019 if let Some(s) = self.name_already_seen.get(&name) {
3025 let old_kind = match (ns, old_binding.module()) {
3026 (ValueNS, _) => "value",
3027 (MacroNS, _) => "macro",
3028 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3029 (TypeNS, Some(module)) if module.is_normal() => "module",
3030 (TypeNS, Some(module)) if module.is_trait() => "trait",
3031 (TypeNS, _) => "type",
3034 let msg = format!("the name `{}` is defined multiple times", name);
3036 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3037 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3038 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3039 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3040 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3042 _ => match (old_binding.is_import(), new_binding.is_import()) {
3043 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3044 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3045 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3050 "`{}` must be defined only once in the {} namespace of this {}",
3056 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3058 self.session.source_map().guess_head_span(old_binding.span),
3059 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3062 // See https://github.com/rust-lang/rust/issues/32354
3063 use NameBindingKind::Import;
3064 let import = match (&new_binding.kind, &old_binding.kind) {
3065 // If there are two imports where one or both have attributes then prefer removing the
3066 // import without attributes.
3067 (Import { import: new, .. }, Import { import: old, .. })
3069 !new_binding.span.is_dummy()
3070 && !old_binding.span.is_dummy()
3071 && (new.has_attributes || old.has_attributes)
3074 if old.has_attributes {
3075 Some((new, new_binding.span, true))
3077 Some((old, old_binding.span, true))
3080 // Otherwise prioritize the new binding.
3081 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3082 Some((import, new_binding.span, other.is_import()))
3084 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3085 Some((import, old_binding.span, other.is_import()))
3090 // Check if the target of the use for both bindings is the same.
3091 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3092 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3094 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3095 // Only suggest removing an import if both bindings are to the same def, if both spans
3096 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3097 // been introduced by an item.
3098 let should_remove_import = duplicate
3100 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3103 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3104 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3106 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3107 // Simple case - remove the entire import. Due to the above match arm, this can
3108 // only be a single use so just remove it entirely.
3109 err.tool_only_span_suggestion(
3110 import.use_span_with_attributes,
3111 "remove unnecessary import",
3113 Applicability::MaybeIncorrect,
3116 Some((import, span, _)) => {
3117 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3123 self.name_already_seen.insert(name, span);
3126 /// This function adds a suggestion to change the binding name of a new import that conflicts
3127 /// with an existing import.
3129 /// ```text,ignore (diagnostic)
3130 /// help: you can use `as` to change the binding name of the import
3132 /// LL | use foo::bar as other_bar;
3133 /// | ^^^^^^^^^^^^^^^^^^^^^
3135 fn add_suggestion_for_rename_of_use(
3137 err: &mut DiagnosticBuilder<'_>,
3139 import: &Import<'_>,
3142 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3143 format!("Other{}", name)
3145 format!("other_{}", name)
3148 let mut suggestion = None;
3150 ImportKind::Single { type_ns_only: true, .. } => {
3151 suggestion = Some(format!("self as {}", suggested_name))
3153 ImportKind::Single { source, .. } => {
3155 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3157 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3158 if pos <= snippet.len() {
3159 suggestion = Some(format!(
3163 if snippet.ends_with(';') { ";" } else { "" }
3169 ImportKind::ExternCrate { source, target, .. } => {
3170 suggestion = Some(format!(
3171 "extern crate {} as {};",
3172 source.unwrap_or(target.name),
3176 _ => unreachable!(),
3179 let rename_msg = "you can use `as` to change the binding name of the import";
3180 if let Some(suggestion) = suggestion {
3181 err.span_suggestion(
3185 Applicability::MaybeIncorrect,
3188 err.span_label(binding_span, rename_msg);
3192 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3193 /// nested. In the following example, this function will be invoked to remove the `a` binding
3194 /// in the second use statement:
3196 /// ```ignore (diagnostic)
3197 /// use issue_52891::a;
3198 /// use issue_52891::{d, a, e};
3201 /// The following suggestion will be added:
3203 /// ```ignore (diagnostic)
3204 /// use issue_52891::{d, a, e};
3205 /// ^-- help: remove unnecessary import
3208 /// If the nested use contains only one import then the suggestion will remove the entire
3211 /// It is expected that the provided import is nested - this isn't checked by the
3212 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3213 /// as characters expected by span manipulations won't be present.
3214 fn add_suggestion_for_duplicate_nested_use(
3216 err: &mut DiagnosticBuilder<'_>,
3217 import: &Import<'_>,
3220 assert!(import.is_nested());
3221 let message = "remove unnecessary import";
3223 // Two examples will be used to illustrate the span manipulations we're doing:
3225 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3226 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3227 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3228 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3230 let (found_closing_brace, span) =
3231 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3233 // If there was a closing brace then identify the span to remove any trailing commas from
3234 // previous imports.
3235 if found_closing_brace {
3236 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3237 err.tool_only_span_suggestion(
3241 Applicability::MaybeIncorrect,
3244 // Remove the entire line if we cannot extend the span back, this indicates an
3245 // `issue_52891::{self}` case.
3246 err.span_suggestion(
3247 import.use_span_with_attributes,
3250 Applicability::MaybeIncorrect,
3257 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3260 fn extern_prelude_get(
3264 ) -> Option<&'a NameBinding<'a>> {
3265 if ident.is_path_segment_keyword() {
3266 // Make sure `self`, `super` etc produce an error when passed to here.
3269 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3270 if let Some(binding) = entry.extern_crate_item {
3271 if !speculative && entry.introduced_by_item {
3272 self.record_use(ident, binding, false);
3276 let crate_id = if !speculative {
3277 self.crate_loader.process_path_extern(ident.name, ident.span)
3279 self.crate_loader.maybe_process_path_extern(ident.name)?
3281 let crate_root = self.expect_module(crate_id.as_def_id());
3283 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3284 .to_name_binding(self.arenas),
3290 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3291 /// isn't something that can be returned because it can't be made to live that long,
3292 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3293 /// just that an error occurred.
3294 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3295 pub fn resolve_str_path_error(
3301 ) -> Result<(ast::Path, Res), ()> {
3302 let path = if path_str.starts_with("::") {
3305 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3306 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3307 .map(|i| self.new_ast_path_segment(i))
3316 .map(Ident::from_str)
3317 .map(|i| self.new_ast_path_segment(i))
3322 let module = self.expect_module(module_id);
3323 let parent_scope = &ParentScope::module(module, self);
3324 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3328 // Resolve a path passed from rustdoc or HIR lowering.
3329 fn resolve_ast_path(
3333 parent_scope: &ParentScope<'a>,
3334 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3335 match self.resolve_path(
3336 &Segment::from_path(path),
3343 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3344 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3345 Ok(path_res.base_res())
3347 PathResult::NonModule(..) => Err((
3349 ResolutionError::FailedToResolve {
3350 label: String::from("type-relative paths are not supported in this context"),
3354 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3355 PathResult::Failed { span, label, suggestion, .. } => {
3356 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3361 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3362 let mut seg = ast::PathSegment::from_ident(ident);
3363 seg.id = self.next_node_id();
3368 pub fn graph_root(&self) -> Module<'a> {
3373 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3377 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3379 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3380 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3383 /// Checks if an expression refers to a function marked with
3384 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3385 /// from the attribute.
3386 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3387 if let ExprKind::Path(None, path) = &expr.kind {
3388 // Don't perform legacy const generics rewriting if the path already
3389 // has generic arguments.
3390 if path.segments.last().unwrap().args.is_some() {
3394 let partial_res = self.partial_res_map.get(&expr.id)?;
3395 if partial_res.unresolved_segments() != 0 {
3399 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3400 // We only support cross-crate argument rewriting. Uses
3401 // within the same crate should be updated to use the new
3402 // const generics style.
3403 if def_id.is_local() {
3407 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3411 let parse_attrs = || {
3412 let attrs = self.cstore().item_attrs(def_id, self.session);
3414 attrs.iter().find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3415 let mut ret = vec![];
3416 for meta in attr.meta_item_list()? {
3417 match meta.literal()?.kind {
3418 LitKind::Int(a, _) => {
3419 ret.push(a as usize);
3421 _ => panic!("invalid arg index"),
3427 // Cache the lookup to avoid parsing attributes for an iterm
3429 let ret = parse_attrs();
3430 self.legacy_const_generic_args.insert(def_id, ret.clone());
3437 fn resolve_main(&mut self) {
3438 let module = self.graph_root;
3439 let ident = Ident::with_dummy_span(sym::main);
3440 let parent_scope = &ParentScope::module(module, self);
3442 let name_binding = match self.resolve_ident_in_module(
3443 ModuleOrUniformRoot::Module(module),
3450 Ok(name_binding) => name_binding,
3454 let res = name_binding.res();
3455 let is_import = name_binding.is_import();
3456 let span = name_binding.span;
3457 if let Res::Def(DefKind::Fn, _) = res {
3458 self.record_use(ident, name_binding, false);
3460 self.main_def = Some(MainDefinition { res, is_import, span });
3464 fn names_to_string(names: &[Symbol]) -> String {
3465 let mut result = String::new();
3466 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3468 result.push_str("::");
3470 if Ident::with_dummy_span(*name).is_raw_guess() {
3471 result.push_str("r#");
3473 result.push_str(&name.as_str());
3478 fn path_names_to_string(path: &Path) -> String {
3479 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3482 /// A somewhat inefficient routine to obtain the name of a module.
3483 fn module_to_string(module: Module<'_>) -> Option<String> {
3484 let mut names = Vec::new();
3486 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3487 if let ModuleKind::Def(.., name) = module.kind {
3488 if let Some(parent) = module.parent {
3490 collect_mod(names, parent);
3493 names.push(Symbol::intern("<opaque>"));
3494 collect_mod(names, module.parent.unwrap());
3497 collect_mod(&mut names, module);
3499 if names.is_empty() {
3503 Some(names_to_string(&names))
3506 #[derive(Copy, Clone, Debug)]
3508 /// Do not issue the lint.
3511 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3512 /// In this case, we can take the span of that path.
3515 /// This lint comes from a `use` statement. In this case, what we
3516 /// care about really is the *root* `use` statement; e.g., if we
3517 /// have nested things like `use a::{b, c}`, we care about the
3519 UsePath { root_id: NodeId, root_span: Span },
3521 /// This is the "trait item" from a fully qualified path. For example,
3522 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3523 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3524 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3528 fn node_id(&self) -> Option<NodeId> {
3530 CrateLint::No => None,
3531 CrateLint::SimplePath(id)
3532 | CrateLint::UsePath { root_id: id, .. }
3533 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3538 pub fn provide(providers: &mut Providers) {
3539 late::lifetimes::provide(providers);