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(bool_to_option)]
14 #![feature(crate_visibility_modifier)]
15 #![feature(format_args_capture)]
17 #![feature(never_type)]
19 #![recursion_limit = "256"]
20 #![allow(rustdoc::private_intra_doc_links)]
22 pub use rustc_hir::def::{Namespace, PerNS};
26 use rustc_arena::{DroplessArena, TypedArena};
27 use rustc_ast::node_id::NodeMap;
28 use rustc_ast::ptr::P;
29 use rustc_ast::visit::{self, Visitor};
30 use rustc_ast::{self as ast, NodeId};
31 use rustc_ast::{Crate, CRATE_NODE_ID};
32 use rustc_ast::{Expr, ExprKind, LitKind};
33 use rustc_ast::{ItemKind, ModKind, Path};
34 use rustc_ast_lowering::ResolverAstLowering;
35 use rustc_ast_pretty::pprust;
36 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
37 use rustc_data_structures::ptr_key::PtrKey;
38 use rustc_data_structures::sync::Lrc;
39 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
40 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
41 use rustc_hir::def::Namespace::*;
42 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
43 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId, CRATE_DEF_INDEX};
44 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
45 use rustc_hir::TraitCandidate;
46 use rustc_index::vec::IndexVec;
47 use rustc_metadata::creader::{CStore, CrateLoader};
48 use rustc_middle::hir::exports::ExportMap;
49 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
50 use rustc_middle::span_bug;
51 use rustc_middle::ty::query::Providers;
52 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
53 use rustc_session::lint;
54 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
55 use rustc_session::Session;
56 use rustc_span::edition::Edition;
57 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
58 use rustc_span::source_map::{CachingSourceMapView, Spanned};
59 use rustc_span::symbol::{kw, sym, Ident, Symbol};
60 use rustc_span::{Span, DUMMY_SP};
62 use smallvec::{smallvec, SmallVec};
63 use std::cell::{Cell, RefCell};
64 use std::collections::{BTreeMap, BTreeSet};
65 use std::ops::ControlFlow;
66 use std::{cmp, fmt, iter, ptr};
69 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
70 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
71 use imports::{Import, ImportKind, ImportResolver, NameResolution};
72 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
73 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
75 type Res = def::Res<NodeId>;
77 mod build_reduced_graph;
90 #[derive(Copy, Clone, PartialEq, Debug)]
91 pub enum Determinacy {
97 fn determined(determined: bool) -> Determinacy {
98 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
102 /// A specific scope in which a name can be looked up.
103 /// This enum is currently used only for early resolution (imports and macros),
104 /// but not for late resolution yet.
105 #[derive(Clone, Copy)]
107 DeriveHelpers(LocalExpnId),
109 MacroRules(MacroRulesScopeRef<'a>),
111 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
112 // lint if it should be reported.
113 Module(Module<'a>, Option<NodeId>),
123 /// Names from different contexts may want to visit different subsets of all specific scopes
124 /// with different restrictions when looking up the resolution.
125 /// This enum is currently used only for early resolution (imports and macros),
126 /// but not for late resolution yet.
127 #[derive(Clone, Copy)]
129 /// All scopes with the given namespace.
130 All(Namespace, /*is_import*/ bool),
131 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
132 AbsolutePath(Namespace),
133 /// All scopes with macro namespace and the given macro kind restriction.
135 /// All scopes with the given namespace, used for partially performing late resolution.
136 /// The node id enables lints and is used for reporting them.
137 Late(Namespace, Module<'a>, Option<NodeId>),
140 /// Everything you need to know about a name's location to resolve it.
141 /// Serves as a starting point for the scope visitor.
142 /// This struct is currently used only for early resolution (imports and macros),
143 /// but not for late resolution yet.
144 #[derive(Clone, Copy, Debug)]
145 pub struct ParentScope<'a> {
147 expansion: LocalExpnId,
148 macro_rules: MacroRulesScopeRef<'a>,
149 derives: &'a [ast::Path],
152 impl<'a> ParentScope<'a> {
153 /// Creates a parent scope with the passed argument used as the module scope component,
154 /// and other scope components set to default empty values.
155 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
158 expansion: LocalExpnId::ROOT,
159 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
165 #[derive(Copy, Debug, Clone)]
166 enum ImplTraitContext {
168 Universal(LocalDefId),
172 struct BindingError {
174 origin: BTreeSet<Span>,
175 target: BTreeSet<Span>,
179 impl PartialOrd for BindingError {
180 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
181 Some(self.cmp(other))
185 impl PartialEq for BindingError {
186 fn eq(&self, other: &BindingError) -> bool {
187 self.name == other.name
191 impl Ord for BindingError {
192 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
193 self.name.cmp(&other.name)
197 enum ResolutionError<'a> {
198 /// Error E0401: can't use type or const parameters from outer function.
199 GenericParamsFromOuterFunction(Res, HasGenericParams),
200 /// Error E0403: the name is already used for a type or const parameter in this generic
202 NameAlreadyUsedInParameterList(Symbol, Span),
203 /// Error E0407: method is not a member of trait.
204 MethodNotMemberOfTrait(Symbol, &'a str),
205 /// Error E0437: type is not a member of trait.
206 TypeNotMemberOfTrait(Symbol, &'a str),
207 /// Error E0438: const is not a member of trait.
208 ConstNotMemberOfTrait(Symbol, &'a str),
209 /// Error E0408: variable `{}` is not bound in all patterns.
210 VariableNotBoundInPattern(&'a BindingError),
211 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
212 VariableBoundWithDifferentMode(Symbol, Span),
213 /// Error E0415: identifier is bound more than once in this parameter list.
214 IdentifierBoundMoreThanOnceInParameterList(Symbol),
215 /// Error E0416: identifier is bound more than once in the same pattern.
216 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
217 /// Error E0426: use of undeclared label.
218 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
219 /// Error E0429: `self` imports are only allowed within a `{ }` list.
220 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
221 /// Error E0430: `self` import can only appear once in the list.
222 SelfImportCanOnlyAppearOnceInTheList,
223 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
224 SelfImportOnlyInImportListWithNonEmptyPrefix,
225 /// Error E0433: failed to resolve.
226 FailedToResolve { label: String, suggestion: Option<Suggestion> },
227 /// Error E0434: can't capture dynamic environment in a fn item.
228 CannotCaptureDynamicEnvironmentInFnItem,
229 /// Error E0435: attempt to use a non-constant value in a constant.
230 AttemptToUseNonConstantValueInConstant(
232 /* suggestion */ &'static str,
233 /* current */ &'static str,
235 /// Error E0530: `X` bindings cannot shadow `Y`s.
236 BindingShadowsSomethingUnacceptable {
237 shadowing_binding_descr: &'static str,
239 participle: &'static str,
240 article: &'static str,
241 shadowed_binding_descr: &'static str,
242 shadowed_binding_span: Span,
244 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
245 ForwardDeclaredGenericParam,
246 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
247 ParamInTyOfConstParam(Symbol),
248 /// generic parameters must not be used inside const evaluations.
250 /// This error is only emitted when using `min_const_generics`.
251 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
252 /// Error E0735: generic parameters with a default cannot use `Self`
253 SelfInGenericParamDefault,
254 /// Error E0767: use of unreachable label
255 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
258 enum VisResolutionError<'a> {
259 Relative2018(Span, &'a ast::Path),
261 FailedToResolve(Span, String, Option<Suggestion>),
262 ExpectedFound(Span, String, Res),
267 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
268 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
269 #[derive(Clone, Copy, Debug)]
273 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
274 /// nonsensical suggestions.
275 has_generic_args: bool,
279 fn from_path(path: &Path) -> Vec<Segment> {
280 path.segments.iter().map(|s| s.into()).collect()
283 fn from_ident(ident: Ident) -> Segment {
284 Segment { ident, id: None, has_generic_args: false }
287 fn names_to_string(segments: &[Segment]) -> String {
288 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
292 impl<'a> From<&'a ast::PathSegment> for Segment {
293 fn from(seg: &'a ast::PathSegment) -> Segment {
294 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
298 struct UsePlacementFinder {
299 target_module: NodeId,
304 impl UsePlacementFinder {
305 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
306 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
307 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
308 visit::walk_crate(&mut finder, krate);
310 (finder.span, finder.found_use)
313 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
314 if self.span.is_some() {
315 return ControlFlow::Break(());
317 if node_id != self.target_module {
318 return ControlFlow::Continue(());
320 // find a use statement
323 ItemKind::Use(..) => {
324 // don't suggest placing a use before the prelude
325 // import or other generated ones
326 if !item.span.from_expansion() {
327 self.span = Some(item.span.shrink_to_lo());
328 self.found_use = true;
329 return ControlFlow::Break(());
332 // don't place use before extern crate
333 ItemKind::ExternCrate(_) => {}
334 // but place them before the first other item
336 if self.span.map_or(true, |span| item.span < span)
337 && !item.span.from_expansion()
339 self.span = Some(item.span.shrink_to_lo());
340 // don't insert between attributes and an item
341 // find the first attribute on the item
342 // FIXME: This is broken for active attributes.
343 for attr in &item.attrs {
344 if !attr.span.is_dummy()
345 && self.span.map_or(true, |span| attr.span < span)
347 self.span = Some(attr.span.shrink_to_lo());
354 ControlFlow::Continue(())
358 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
359 fn visit_item(&mut self, item: &'tcx ast::Item) {
360 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
361 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
365 visit::walk_item(self, item);
369 /// An intermediate resolution result.
371 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
372 /// items are visible in their whole block, while `Res`es only from the place they are defined
375 enum LexicalScopeBinding<'a> {
376 Item(&'a NameBinding<'a>),
380 impl<'a> LexicalScopeBinding<'a> {
381 fn res(self) -> Res {
383 LexicalScopeBinding::Item(binding) => binding.res(),
384 LexicalScopeBinding::Res(res) => res,
389 #[derive(Copy, Clone, Debug)]
390 enum ModuleOrUniformRoot<'a> {
394 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
395 CrateRootAndExternPrelude,
397 /// Virtual module that denotes resolution in extern prelude.
398 /// Used for paths starting with `::` on 2018 edition.
401 /// Virtual module that denotes resolution in current scope.
402 /// Used only for resolving single-segment imports. The reason it exists is that import paths
403 /// are always split into two parts, the first of which should be some kind of module.
407 impl ModuleOrUniformRoot<'_> {
408 fn same_def(lhs: Self, rhs: Self) -> bool {
410 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
411 lhs.def_id() == rhs.def_id()
414 ModuleOrUniformRoot::CrateRootAndExternPrelude,
415 ModuleOrUniformRoot::CrateRootAndExternPrelude,
417 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
418 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
424 #[derive(Clone, Debug)]
425 enum PathResult<'a> {
426 Module(ModuleOrUniformRoot<'a>),
427 NonModule(PartialRes),
432 suggestion: Option<Suggestion>,
433 is_error_from_last_segment: bool,
439 /// An anonymous module; e.g., just a block.
444 /// { // This is an anonymous module
445 /// f(); // This resolves to (2) as we are inside the block.
448 /// f(); // Resolves to (1)
452 /// Any module with a name.
456 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
457 /// or the crate root (which is conceptually a top-level module).
458 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
459 /// * A trait or an enum (it implicitly contains associated types, methods and variant
461 Def(DefKind, DefId, Symbol),
465 /// Get name of the module.
466 pub fn name(&self) -> Option<Symbol> {
468 ModuleKind::Block(..) => None,
469 ModuleKind::Def(.., name) => Some(*name),
474 /// A key that identifies a binding in a given `Module`.
476 /// Multiple bindings in the same module can have the same key (in a valid
477 /// program) if all but one of them come from glob imports.
478 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
480 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
484 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
485 /// `_` in the expanded AST that introduced this binding.
489 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
491 /// One node in the tree of modules.
493 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
496 /// * crate root (aka, top-level anonymous module)
499 /// * curly-braced block with statements
501 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
502 pub struct ModuleData<'a> {
503 /// The direct parent module (it may not be a `mod`, however).
504 parent: Option<Module<'a>>,
505 /// What kind of module this is, because this may not be a `mod`.
508 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
509 /// This may be the crate root.
510 nearest_parent_mod: DefId,
512 /// Mapping between names and their (possibly in-progress) resolutions in this module.
513 /// Resolutions in modules from other crates are not populated until accessed.
514 lazy_resolutions: Resolutions<'a>,
515 /// True if this is a module from other crate that needs to be populated on access.
516 populate_on_access: Cell<bool>,
518 /// Macro invocations that can expand into items in this module.
519 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
521 /// Whether `#[no_implicit_prelude]` is active.
522 no_implicit_prelude: bool,
524 glob_importers: RefCell<Vec<&'a Import<'a>>>,
525 globs: RefCell<Vec<&'a Import<'a>>>,
527 /// Used to memoize the traits in this module for faster searches through all traits in scope.
528 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
530 /// Span of the module itself. Used for error reporting.
536 type Module<'a> = &'a ModuleData<'a>;
538 impl<'a> ModuleData<'a> {
540 parent: Option<Module<'a>>,
542 nearest_parent_mod: DefId,
550 lazy_resolutions: Default::default(),
551 populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
552 unexpanded_invocations: Default::default(),
553 no_implicit_prelude: false,
554 glob_importers: RefCell::new(Vec::new()),
555 globs: RefCell::new(Vec::new()),
556 traits: RefCell::new(None),
562 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
564 R: AsMut<Resolver<'a>>,
565 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
567 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
568 if let Some(binding) = name_resolution.borrow().binding {
569 f(resolver, key.ident, key.ns, binding);
574 /// This modifies `self` in place. The traits will be stored in `self.traits`.
575 fn ensure_traits<R>(&'a self, resolver: &mut R)
577 R: AsMut<Resolver<'a>>,
579 let mut traits = self.traits.borrow_mut();
580 if traits.is_none() {
581 let mut collected_traits = Vec::new();
582 self.for_each_child(resolver, |_, name, ns, binding| {
586 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
587 collected_traits.push((name, binding))
590 *traits = Some(collected_traits.into_boxed_slice());
594 fn res(&self) -> Option<Res> {
596 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
601 fn def_id(&self) -> Option<DefId> {
603 ModuleKind::Def(_, def_id, _) => Some(def_id),
608 // `self` resolves to the first module ancestor that `is_normal`.
609 fn is_normal(&self) -> bool {
610 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
613 fn is_trait(&self) -> bool {
614 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
617 fn nearest_item_scope(&'a self) -> Module<'a> {
619 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
620 self.parent.expect("enum or trait module without a parent")
626 fn is_ancestor_of(&self, mut other: &Self) -> bool {
627 while !ptr::eq(self, other) {
628 if let Some(parent) = other.parent {
638 impl<'a> fmt::Debug for ModuleData<'a> {
639 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
640 write!(f, "{:?}", self.res())
644 /// Records a possibly-private value, type, or module definition.
645 #[derive(Clone, Debug)]
646 pub struct NameBinding<'a> {
647 kind: NameBindingKind<'a>,
648 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
649 expansion: LocalExpnId,
654 pub trait ToNameBinding<'a> {
655 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
658 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
659 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
664 #[derive(Clone, Debug)]
665 enum NameBindingKind<'a> {
666 Res(Res, /* is_macro_export */ bool),
668 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
671 impl<'a> NameBindingKind<'a> {
672 /// Is this a name binding of an import?
673 fn is_import(&self) -> bool {
674 matches!(*self, NameBindingKind::Import { .. })
678 struct PrivacyError<'a> {
680 binding: &'a NameBinding<'a>,
684 struct UseError<'a> {
685 err: DiagnosticBuilder<'a>,
686 /// Candidates which user could `use` to access the missing type.
687 candidates: Vec<ImportSuggestion>,
688 /// The `DefId` of the module to place the use-statements in.
690 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
692 /// Extra free-form suggestion.
693 suggestion: Option<(Span, &'static str, String, Applicability)>,
696 #[derive(Clone, Copy, PartialEq, Debug)]
701 MacroRulesVsModularized,
709 fn descr(self) -> &'static str {
711 AmbiguityKind::Import => "name vs any other name during import resolution",
712 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
713 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
714 AmbiguityKind::MacroRulesVsModularized => {
715 "`macro_rules` vs non-`macro_rules` from other module"
717 AmbiguityKind::GlobVsOuter => {
718 "glob import vs any other name from outer scope during import/macro resolution"
720 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
721 AmbiguityKind::GlobVsExpanded => {
722 "glob import vs macro-expanded name in the same \
723 module during import/macro resolution"
725 AmbiguityKind::MoreExpandedVsOuter => {
726 "macro-expanded name vs less macro-expanded name \
727 from outer scope during import/macro resolution"
733 /// Miscellaneous bits of metadata for better ambiguity error reporting.
734 #[derive(Clone, Copy, PartialEq)]
735 enum AmbiguityErrorMisc {
742 struct AmbiguityError<'a> {
745 b1: &'a NameBinding<'a>,
746 b2: &'a NameBinding<'a>,
747 misc1: AmbiguityErrorMisc,
748 misc2: AmbiguityErrorMisc,
751 impl<'a> NameBinding<'a> {
752 fn module(&self) -> Option<Module<'a>> {
754 NameBindingKind::Module(module) => Some(module),
755 NameBindingKind::Import { binding, .. } => binding.module(),
760 fn res(&self) -> Res {
762 NameBindingKind::Res(res, _) => res,
763 NameBindingKind::Module(module) => module.res().unwrap(),
764 NameBindingKind::Import { binding, .. } => binding.res(),
768 fn is_ambiguity(&self) -> bool {
769 self.ambiguity.is_some()
771 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
776 fn is_possibly_imported_variant(&self) -> bool {
778 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
779 NameBindingKind::Res(
780 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
783 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
787 fn is_extern_crate(&self) -> bool {
789 NameBindingKind::Import {
790 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
793 NameBindingKind::Module(&ModuleData {
794 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
796 }) => def_id.index == CRATE_DEF_INDEX,
801 fn is_import(&self) -> bool {
802 matches!(self.kind, NameBindingKind::Import { .. })
805 fn is_glob_import(&self) -> bool {
807 NameBindingKind::Import { import, .. } => import.is_glob(),
812 fn is_importable(&self) -> bool {
815 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
819 fn is_macro_def(&self) -> bool {
820 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
823 fn macro_kind(&self) -> Option<MacroKind> {
824 self.res().macro_kind()
827 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
828 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
829 // Then this function returns `true` if `self` may emerge from a macro *after* that
830 // in some later round and screw up our previously found resolution.
831 // See more detailed explanation in
832 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
835 invoc_parent_expansion: LocalExpnId,
836 binding: &NameBinding<'_>,
838 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
839 // Expansions are partially ordered, so "may appear after" is an inversion of
840 // "certainly appears before or simultaneously" and includes unordered cases.
841 let self_parent_expansion = self.expansion;
842 let other_parent_expansion = binding.expansion;
843 let certainly_before_other_or_simultaneously =
844 other_parent_expansion.is_descendant_of(self_parent_expansion);
845 let certainly_before_invoc_or_simultaneously =
846 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
847 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
851 #[derive(Debug, Default, Clone)]
852 pub struct ExternPreludeEntry<'a> {
853 extern_crate_item: Option<&'a NameBinding<'a>>,
854 pub introduced_by_item: bool,
857 /// Used for better errors for E0773
858 enum BuiltinMacroState {
859 NotYetSeen(SyntaxExtensionKind),
864 resolutions: DeriveResolutions,
865 helper_attrs: Vec<(usize, Ident)>,
866 has_derive_copy: bool,
869 /// The main resolver class.
871 /// This is the visitor that walks the whole crate.
872 pub struct Resolver<'a> {
873 session: &'a Session,
875 definitions: Definitions,
877 graph_root: Module<'a>,
879 prelude: Option<Module<'a>>,
880 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
882 /// N.B., this is used only for better diagnostics, not name resolution itself.
883 has_self: FxHashSet<DefId>,
885 /// Names of fields of an item `DefId` accessible with dot syntax.
886 /// Used for hints during error reporting.
887 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
889 /// All imports known to succeed or fail.
890 determined_imports: Vec<&'a Import<'a>>,
892 /// All non-determined imports.
893 indeterminate_imports: Vec<&'a Import<'a>>,
895 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
896 /// We are resolving a last import segment during import validation.
897 last_import_segment: bool,
898 /// This binding should be ignored during in-module resolution, so that we don't get
899 /// "self-confirming" import resolutions during import validation.
900 unusable_binding: Option<&'a NameBinding<'a>>,
902 // Spans for local variables found during pattern resolution.
903 // Used for suggestions during error reporting.
904 pat_span_map: NodeMap<Span>,
906 /// Resolutions for nodes that have a single resolution.
907 partial_res_map: NodeMap<PartialRes>,
908 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
909 import_res_map: NodeMap<PerNS<Option<Res>>>,
910 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
911 label_res_map: NodeMap<NodeId>,
913 /// `CrateNum` resolutions of `extern crate` items.
914 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
915 export_map: ExportMap,
916 trait_map: Option<NodeMap<Vec<TraitCandidate>>>,
918 /// A map from nodes to anonymous modules.
919 /// Anonymous modules are pseudo-modules that are implicitly created around items
920 /// contained within blocks.
922 /// For example, if we have this:
930 /// There will be an anonymous module created around `g` with the ID of the
931 /// entry block for `f`.
932 block_map: NodeMap<Module<'a>>,
933 /// A fake module that contains no definition and no prelude. Used so that
934 /// some AST passes can generate identifiers that only resolve to local or
936 empty_module: Module<'a>,
937 module_map: FxHashMap<LocalDefId, Module<'a>>,
938 extern_module_map: FxHashMap<DefId, Module<'a>>,
939 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
940 underscore_disambiguator: u32,
942 /// Maps glob imports to the names of items actually imported.
943 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
944 /// Visibilities in "lowered" form, for all entities that have them.
945 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
946 used_imports: FxHashSet<NodeId>,
947 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
948 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
950 /// Privacy errors are delayed until the end in order to deduplicate them.
951 privacy_errors: Vec<PrivacyError<'a>>,
952 /// Ambiguity errors are delayed for deduplication.
953 ambiguity_errors: Vec<AmbiguityError<'a>>,
954 /// `use` injections are delayed for better placement and deduplication.
955 use_injections: Vec<UseError<'a>>,
956 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
957 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
959 arenas: &'a ResolverArenas<'a>,
960 dummy_binding: &'a NameBinding<'a>,
962 crate_loader: CrateLoader<'a>,
963 macro_names: FxHashSet<Ident>,
964 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
965 registered_attrs: FxHashSet<Ident>,
966 registered_tools: FxHashSet<Ident>,
967 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
968 all_macros: FxHashMap<Symbol, Res>,
969 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
970 dummy_ext_bang: Lrc<SyntaxExtension>,
971 dummy_ext_derive: Lrc<SyntaxExtension>,
972 non_macro_attr: Lrc<SyntaxExtension>,
973 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
974 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
975 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
976 proc_macro_stubs: FxHashSet<LocalDefId>,
977 /// Traces collected during macro resolution and validated when it's complete.
978 single_segment_macro_resolutions:
979 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
980 multi_segment_macro_resolutions:
981 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
982 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
983 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
984 /// Derive macros cannot modify the item themselves and have to store the markers in the global
985 /// context, so they attach the markers to derive container IDs using this resolver table.
986 containers_deriving_copy: FxHashSet<LocalExpnId>,
987 /// Parent scopes in which the macros were invoked.
988 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
989 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
990 /// `macro_rules` scopes *produced* by expanding the macro invocations,
991 /// include all the `macro_rules` items and other invocations generated by them.
992 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
993 /// Helper attributes that are in scope for the given expansion.
994 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
995 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
996 /// with the given `ExpnId`.
997 derive_data: FxHashMap<LocalExpnId, DeriveData>,
999 /// Avoid duplicated errors for "name already defined".
1000 name_already_seen: FxHashMap<Symbol, Span>,
1002 potentially_unused_imports: Vec<&'a Import<'a>>,
1004 /// Table for mapping struct IDs into struct constructor IDs,
1005 /// it's not used during normal resolution, only for better error reporting.
1006 /// Also includes of list of each fields visibility
1007 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1009 /// Features enabled for this crate.
1010 active_features: FxHashSet<Symbol>,
1012 lint_buffer: LintBuffer,
1014 next_node_id: NodeId,
1016 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1017 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1019 /// Indices of unnamed struct or variant fields with unresolved attributes.
1020 placeholder_field_indices: FxHashMap<NodeId, usize>,
1021 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1022 /// we know what parent node that fragment should be attached to thanks to this table,
1023 /// and how the `impl Trait` fragments were introduced.
1024 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1026 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1027 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1028 /// FIXME: Replace with a more general AST map (together with some other fields).
1029 trait_impl_items: FxHashSet<LocalDefId>,
1031 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1032 /// Amount of lifetime parameters for each item in the crate.
1033 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1035 main_def: Option<MainDefinition>,
1036 trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
1037 /// A list of proc macro LocalDefIds, written out in the order in which
1038 /// they are declared in the static array generated by proc_macro_harness.
1039 proc_macros: Vec<NodeId>,
1040 confused_type_with_std_module: FxHashMap<Span, Span>,
1043 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1045 pub struct ResolverArenas<'a> {
1046 modules: TypedArena<ModuleData<'a>>,
1047 local_modules: RefCell<Vec<Module<'a>>>,
1048 imports: TypedArena<Import<'a>>,
1049 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1050 ast_paths: TypedArena<ast::Path>,
1051 dropless: DroplessArena,
1054 impl<'a> ResolverArenas<'a> {
1055 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1056 let module = self.modules.alloc(module);
1057 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1058 self.local_modules.borrow_mut().push(module);
1062 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1063 self.local_modules.borrow()
1065 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1066 self.dropless.alloc(name_binding)
1068 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1069 self.imports.alloc(import)
1071 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1072 self.name_resolutions.alloc(Default::default())
1074 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1075 PtrKey(self.dropless.alloc(Cell::new(scope)))
1077 fn alloc_macro_rules_binding(
1079 binding: MacroRulesBinding<'a>,
1080 ) -> &'a MacroRulesBinding<'a> {
1081 self.dropless.alloc(binding)
1083 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1084 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1086 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1087 self.dropless.alloc_from_iter(spans)
1091 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1092 fn as_mut(&mut self) -> &mut Resolver<'a> {
1097 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1098 fn parent(self, id: DefId) -> Option<DefId> {
1099 match id.as_local() {
1100 Some(id) => self.definitions.def_key(id).parent,
1101 None => self.cstore().def_key(id).parent,
1103 .map(|index| DefId { index, ..id })
1107 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1108 /// the resolver is no longer needed as all the relevant information is inline.
1109 impl ResolverAstLowering for Resolver<'_> {
1110 fn def_key(&mut self, id: DefId) -> DefKey {
1111 if let Some(id) = id.as_local() {
1112 self.definitions().def_key(id)
1114 self.cstore().def_key(id)
1119 fn def_span(&self, id: LocalDefId) -> Span {
1120 self.definitions.def_span(id)
1123 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1124 if let Some(def_id) = def_id.as_local() {
1125 self.item_generics_num_lifetimes[&def_id]
1127 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1131 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1132 self.legacy_const_generic_args(expr)
1135 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1136 self.partial_res_map.get(&id).cloned()
1139 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1140 self.import_res_map.get(&id).cloned().unwrap_or_default()
1143 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1144 self.label_res_map.get(&id).cloned()
1147 fn definitions(&mut self) -> &mut Definitions {
1148 &mut self.definitions
1151 fn lint_buffer(&mut self) -> &mut LintBuffer {
1152 &mut self.lint_buffer
1155 fn next_node_id(&mut self) -> NodeId {
1159 fn take_trait_map(&mut self) -> NodeMap<Vec<TraitCandidate>> {
1160 std::mem::replace(&mut self.trait_map, None).unwrap()
1163 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1164 self.node_id_to_def_id.get(&node).copied()
1167 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1168 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1171 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1172 match def_id.as_local() {
1173 Some(def_id) => self.definitions.def_path_hash(def_id),
1174 None => self.cstore().def_path_hash(def_id),
1178 /// Adds a definition with a parent definition.
1182 node_id: ast::NodeId,
1188 !self.node_id_to_def_id.contains_key(&node_id),
1189 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1192 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1195 // Find the next free disambiguator for this key.
1196 let next_disambiguator = &mut self.next_disambiguator;
1197 let next_disambiguator = |parent, data| {
1198 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1199 let disambiguator = *next_disamb;
1200 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1204 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1206 // Some things for which we allocate `LocalDefId`s don't correspond to
1207 // anything in the AST, so they don't have a `NodeId`. For these cases
1208 // we don't need a mapping from `NodeId` to `LocalDefId`.
1209 if node_id != ast::DUMMY_NODE_ID {
1210 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1211 self.node_id_to_def_id.insert(node_id, def_id);
1213 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1219 struct ExpandHasher<'a, 'b> {
1220 source_map: CachingSourceMapView<'a>,
1221 resolver: &'a Resolver<'b>,
1224 impl<'a, 'b> rustc_span::HashStableContext for ExpandHasher<'a, 'b> {
1226 fn hash_spans(&self) -> bool {
1231 fn def_span(&self, id: LocalDefId) -> Span {
1232 self.resolver.def_span(id)
1236 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1237 self.resolver.def_path_hash(def_id)
1241 fn span_data_to_lines_and_cols(
1243 span: &rustc_span::SpanData,
1244 ) -> Option<(Lrc<rustc_span::SourceFile>, usize, rustc_span::BytePos, usize, rustc_span::BytePos)>
1246 self.source_map.span_data_to_lines_and_cols(span)
1250 impl<'a> Resolver<'a> {
1252 session: &'a Session,
1255 metadata_loader: Box<MetadataLoaderDyn>,
1256 arenas: &'a ResolverArenas<'a>,
1258 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1259 let root_def_id = root_local_def_id.to_def_id();
1260 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1261 let graph_root = arenas.alloc_module(ModuleData {
1262 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1263 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1265 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1266 let empty_module = arenas.alloc_module(ModuleData {
1267 no_implicit_prelude: true,
1276 let mut module_map = FxHashMap::default();
1277 module_map.insert(root_local_def_id, graph_root);
1279 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1280 let root = definitions.get_root_def();
1282 let mut visibilities = FxHashMap::default();
1283 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1285 let mut def_id_to_node_id = IndexVec::default();
1286 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1287 let mut node_id_to_def_id = FxHashMap::default();
1288 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1290 let mut invocation_parents = FxHashMap::default();
1291 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1293 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1297 .filter(|(_, entry)| entry.add_prelude)
1298 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1301 if !session.contains_name(&krate.attrs, sym::no_core) {
1302 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1303 if !session.contains_name(&krate.attrs, sym::no_std) {
1304 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1308 let (registered_attrs, registered_tools) =
1309 macros::registered_attrs_and_tools(session, &krate.attrs);
1311 let features = session.features_untracked();
1313 let mut resolver = Resolver {
1318 // The outermost module has def ID 0; this is not reflected in the
1324 has_self: FxHashSet::default(),
1325 field_names: FxHashMap::default(),
1327 determined_imports: Vec::new(),
1328 indeterminate_imports: Vec::new(),
1330 last_import_segment: false,
1331 unusable_binding: None,
1333 pat_span_map: Default::default(),
1334 partial_res_map: Default::default(),
1335 import_res_map: Default::default(),
1336 label_res_map: Default::default(),
1337 extern_crate_map: Default::default(),
1338 export_map: FxHashMap::default(),
1339 trait_map: Some(NodeMap::default()),
1340 underscore_disambiguator: 0,
1343 block_map: Default::default(),
1344 extern_module_map: FxHashMap::default(),
1345 binding_parent_modules: FxHashMap::default(),
1346 ast_transform_scopes: FxHashMap::default(),
1348 glob_map: Default::default(),
1350 used_imports: FxHashSet::default(),
1351 maybe_unused_trait_imports: Default::default(),
1352 maybe_unused_extern_crates: Vec::new(),
1354 privacy_errors: Vec::new(),
1355 ambiguity_errors: Vec::new(),
1356 use_injections: Vec::new(),
1357 macro_expanded_macro_export_errors: BTreeSet::new(),
1360 dummy_binding: arenas.alloc_name_binding(NameBinding {
1361 kind: NameBindingKind::Res(Res::Err, false),
1363 expansion: LocalExpnId::ROOT,
1365 vis: ty::Visibility::Public,
1368 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1369 macro_names: FxHashSet::default(),
1370 builtin_macros: Default::default(),
1373 macro_use_prelude: FxHashMap::default(),
1374 all_macros: FxHashMap::default(),
1375 macro_map: FxHashMap::default(),
1376 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1377 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1378 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1379 invocation_parent_scopes: Default::default(),
1380 output_macro_rules_scopes: Default::default(),
1381 helper_attrs: Default::default(),
1382 derive_data: Default::default(),
1383 local_macro_def_scopes: FxHashMap::default(),
1384 name_already_seen: FxHashMap::default(),
1385 potentially_unused_imports: Vec::new(),
1386 struct_constructors: Default::default(),
1387 unused_macros: Default::default(),
1388 proc_macro_stubs: Default::default(),
1389 single_segment_macro_resolutions: Default::default(),
1390 multi_segment_macro_resolutions: Default::default(),
1391 builtin_attrs: Default::default(),
1392 containers_deriving_copy: Default::default(),
1393 active_features: features
1394 .declared_lib_features
1396 .map(|(feat, ..)| *feat)
1397 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1399 lint_buffer: LintBuffer::default(),
1400 next_node_id: NodeId::from_u32(1),
1403 placeholder_field_indices: Default::default(),
1405 next_disambiguator: Default::default(),
1406 trait_impl_items: Default::default(),
1407 legacy_const_generic_args: Default::default(),
1408 item_generics_num_lifetimes: Default::default(),
1409 main_def: Default::default(),
1410 trait_impls: Default::default(),
1411 proc_macros: Default::default(),
1412 confused_type_with_std_module: Default::default(),
1415 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1416 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1421 fn create_stable_hashing_context(&self) -> ExpandHasher<'_, 'a> {
1423 source_map: CachingSourceMapView::new(self.session.source_map()),
1428 pub fn next_node_id(&mut self) -> NodeId {
1433 .expect("input too large; ran out of NodeIds");
1434 self.next_node_id = ast::NodeId::from_usize(next);
1438 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1439 &mut self.lint_buffer
1442 pub fn arenas() -> ResolverArenas<'a> {
1446 pub fn into_outputs(self) -> ResolverOutputs {
1447 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1448 let definitions = self.definitions;
1449 let visibilities = self.visibilities;
1450 let extern_crate_map = self.extern_crate_map;
1451 let export_map = self.export_map;
1452 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1453 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1454 let glob_map = self.glob_map;
1455 let main_def = self.main_def;
1456 let confused_type_with_std_module = self.confused_type_with_std_module;
1459 cstore: Box::new(self.crate_loader.into_cstore()),
1464 maybe_unused_trait_imports,
1465 maybe_unused_extern_crates,
1466 extern_prelude: self
1469 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1472 trait_impls: self.trait_impls,
1474 confused_type_with_std_module,
1478 pub fn clone_outputs(&self) -> ResolverOutputs {
1479 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1481 definitions: self.definitions.clone(),
1482 cstore: Box::new(self.cstore().clone()),
1483 visibilities: self.visibilities.clone(),
1484 extern_crate_map: self.extern_crate_map.clone(),
1485 export_map: self.export_map.clone(),
1486 glob_map: self.glob_map.clone(),
1487 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1488 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1489 extern_prelude: self
1492 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1494 main_def: self.main_def,
1495 trait_impls: self.trait_impls.clone(),
1497 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1501 pub fn cstore(&self) -> &CStore {
1502 self.crate_loader.cstore()
1505 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1507 MacroKind::Bang => self.dummy_ext_bang.clone(),
1508 MacroKind::Derive => self.dummy_ext_derive.clone(),
1509 MacroKind::Attr => self.non_macro_attr.clone(),
1513 /// Runs the function on each namespace.
1514 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1520 fn is_builtin_macro(&mut self, res: Res) -> bool {
1521 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1524 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1526 match ctxt.outer_expn_data().macro_def_id {
1527 Some(def_id) => return def_id,
1528 None => ctxt.remove_mark(),
1533 /// Entry point to crate resolution.
1534 pub fn resolve_crate(&mut self, krate: &Crate) {
1535 self.session.time("resolve_crate", || {
1536 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1537 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1538 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1539 self.session.time("resolve_main", || self.resolve_main());
1540 self.session.time("resolve_check_unused", || self.check_unused(krate));
1541 self.session.time("resolve_report_errors", || self.report_errors(krate));
1542 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1546 pub fn traits_in_scope(
1548 current_trait: Option<Module<'a>>,
1549 parent_scope: &ParentScope<'a>,
1550 ctxt: SyntaxContext,
1551 assoc_item: Option<(Symbol, Namespace)>,
1552 ) -> Vec<TraitCandidate> {
1553 let mut found_traits = Vec::new();
1555 if let Some(module) = current_trait {
1556 if self.trait_may_have_item(Some(module), assoc_item) {
1557 let def_id = module.def_id().unwrap();
1558 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1562 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1564 Scope::Module(module, _) => {
1565 this.traits_in_module(module, assoc_item, &mut found_traits);
1567 Scope::StdLibPrelude => {
1568 if let Some(module) = this.prelude {
1569 this.traits_in_module(module, assoc_item, &mut found_traits);
1572 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1573 _ => unreachable!(),
1581 fn traits_in_module(
1584 assoc_item: Option<(Symbol, Namespace)>,
1585 found_traits: &mut Vec<TraitCandidate>,
1587 module.ensure_traits(self);
1588 let traits = module.traits.borrow();
1589 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1590 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1591 let def_id = trait_binding.res().def_id();
1592 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1593 found_traits.push(TraitCandidate { def_id, import_ids });
1598 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1599 // associated item with the given name and namespace (if specified). This is a conservative
1600 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1601 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1602 // associated items.
1603 fn trait_may_have_item(
1605 trait_module: Option<Module<'a>>,
1606 assoc_item: Option<(Symbol, Namespace)>,
1608 match (trait_module, assoc_item) {
1609 (Some(trait_module), Some((name, ns))) => {
1610 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1611 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1612 assoc_ns == ns && assoc_ident.name == name
1619 fn find_transitive_imports(
1621 mut kind: &NameBindingKind<'_>,
1623 ) -> SmallVec<[LocalDefId; 1]> {
1624 let mut import_ids = smallvec![];
1625 while let NameBindingKind::Import { import, binding, .. } = kind {
1626 let id = self.local_def_id(import.id);
1627 self.maybe_unused_trait_imports.insert(id);
1628 self.add_to_glob_map(&import, trait_name);
1629 import_ids.push(id);
1630 kind = &binding.kind;
1639 nearest_parent_mod: DefId,
1643 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1644 self.arenas.alloc_module(module)
1647 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1648 let ident = ident.normalize_to_macros_2_0();
1649 let disambiguator = if ident.name == kw::Underscore {
1650 self.underscore_disambiguator += 1;
1651 self.underscore_disambiguator
1655 BindingKey { ident, ns, disambiguator }
1658 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1659 if module.populate_on_access.get() {
1660 module.populate_on_access.set(false);
1661 self.build_reduced_graph_external(module);
1663 &module.lazy_resolutions
1670 ) -> &'a RefCell<NameResolution<'a>> {
1672 .resolutions(module)
1675 .or_insert_with(|| self.arenas.alloc_name_resolution())
1681 used_binding: &'a NameBinding<'a>,
1682 is_lexical_scope: bool,
1684 if let Some((b2, kind)) = used_binding.ambiguity {
1685 self.ambiguity_errors.push(AmbiguityError {
1690 misc1: AmbiguityErrorMisc::None,
1691 misc2: AmbiguityErrorMisc::None,
1694 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1695 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1696 // but not introduce it, as used if they are accessed from lexical scope.
1697 if is_lexical_scope {
1698 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1699 if let Some(crate_item) = entry.extern_crate_item {
1700 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1707 import.used.set(true);
1708 self.used_imports.insert(import.id);
1709 self.add_to_glob_map(&import, ident);
1710 self.record_use(ident, binding, false);
1715 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1716 if import.is_glob() {
1717 let def_id = self.local_def_id(import.id);
1718 self.glob_map.entry(def_id).or_default().insert(ident.name);
1722 /// A generic scope visitor.
1723 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1724 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1727 scope_set: ScopeSet<'a>,
1728 parent_scope: &ParentScope<'a>,
1729 ctxt: SyntaxContext,
1730 mut visitor: impl FnMut(
1733 /*use_prelude*/ bool,
1737 // General principles:
1738 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1739 // built into the language or standard library. This way we can add new names into the
1740 // language or standard library without breaking user code.
1741 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1742 // Places to search (in order of decreasing priority):
1744 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1745 // (open set, not controlled).
1746 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1747 // (open, not controlled).
1748 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1749 // 4. Tool modules (closed, controlled right now, but not in the future).
1750 // 5. Standard library prelude (de-facto closed, controlled).
1751 // 6. Language prelude (closed, controlled).
1753 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1754 // (open set, not controlled).
1755 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1756 // (open, not controlled).
1757 // 3. Standard library prelude (de-facto closed, controlled).
1759 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1760 // are currently reported as errors. They should be higher in priority than preludes
1761 // and probably even names in modules according to the "general principles" above. They
1762 // also should be subject to restricted shadowing because are effectively produced by
1763 // derives (you need to resolve the derive first to add helpers into scope), but they
1764 // should be available before the derive is expanded for compatibility.
1765 // It's mess in general, so we are being conservative for now.
1766 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1767 // priority than prelude macros, but create ambiguities with macros in modules.
1768 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1769 // (open, not controlled). Have higher priority than prelude macros, but create
1770 // ambiguities with `macro_rules`.
1771 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1772 // 4a. User-defined prelude from macro-use
1773 // (open, the open part is from macro expansions, not controlled).
1774 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1775 // 4c. Standard library prelude (de-facto closed, controlled).
1776 // 6. Language prelude: builtin attributes (closed, controlled).
1778 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1779 let (ns, macro_kind, is_absolute_path) = match scope_set {
1780 ScopeSet::All(ns, _) => (ns, None, false),
1781 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1782 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1783 ScopeSet::Late(ns, ..) => (ns, None, false),
1785 let module = match scope_set {
1786 // Start with the specified module.
1787 ScopeSet::Late(_, module, _) => module,
1788 // Jump out of trait or enum modules, they do not act as scopes.
1789 _ => parent_scope.module.nearest_item_scope(),
1791 let mut scope = match ns {
1792 _ if is_absolute_path => Scope::CrateRoot,
1793 TypeNS | ValueNS => Scope::Module(module, None),
1794 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1796 let mut ctxt = ctxt.normalize_to_macros_2_0();
1797 let mut use_prelude = !module.no_implicit_prelude;
1800 let visit = match scope {
1801 // Derive helpers are not in scope when resolving derives in the same container.
1802 Scope::DeriveHelpers(expn_id) => {
1803 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1805 Scope::DeriveHelpersCompat => true,
1806 Scope::MacroRules(macro_rules_scope) => {
1807 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1808 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1809 // As another consequence of this optimization visitors never observe invocation
1810 // scopes for macros that were already expanded.
1811 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1812 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1813 macro_rules_scope.set(next_scope.get());
1820 Scope::CrateRoot => true,
1821 Scope::Module(..) => true,
1822 Scope::RegisteredAttrs => use_prelude,
1823 Scope::MacroUsePrelude => use_prelude || rust_2015,
1824 Scope::BuiltinAttrs => true,
1825 Scope::ExternPrelude => use_prelude || is_absolute_path,
1826 Scope::ToolPrelude => use_prelude,
1827 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1828 Scope::BuiltinTypes => true,
1832 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1833 return break_result;
1837 scope = match scope {
1838 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1839 Scope::DeriveHelpers(expn_id) => {
1840 // Derive helpers are not visible to code generated by bang or derive macros.
1841 let expn_data = expn_id.expn_data();
1842 match expn_data.kind {
1844 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1845 Scope::DeriveHelpersCompat
1847 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1850 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1851 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1852 MacroRulesScope::Binding(binding) => {
1853 Scope::MacroRules(binding.parent_macro_rules_scope)
1855 MacroRulesScope::Invocation(invoc_id) => {
1856 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1858 MacroRulesScope::Empty => Scope::Module(module, None),
1860 Scope::CrateRoot => match ns {
1862 ctxt.adjust(ExpnId::root());
1863 Scope::ExternPrelude
1865 ValueNS | MacroNS => break,
1867 Scope::Module(module, prev_lint_id) => {
1868 use_prelude = !module.no_implicit_prelude;
1869 let derive_fallback_lint_id = match scope_set {
1870 ScopeSet::Late(.., lint_id) => lint_id,
1873 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1874 Some((parent_module, lint_id)) => {
1875 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1878 ctxt.adjust(ExpnId::root());
1880 TypeNS => Scope::ExternPrelude,
1881 ValueNS => Scope::StdLibPrelude,
1882 MacroNS => Scope::RegisteredAttrs,
1887 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1888 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1889 Scope::BuiltinAttrs => break, // nowhere else to search
1890 Scope::ExternPrelude if is_absolute_path => break,
1891 Scope::ExternPrelude => Scope::ToolPrelude,
1892 Scope::ToolPrelude => Scope::StdLibPrelude,
1893 Scope::StdLibPrelude => match ns {
1894 TypeNS => Scope::BuiltinTypes,
1895 ValueNS => break, // nowhere else to search
1896 MacroNS => Scope::BuiltinAttrs,
1898 Scope::BuiltinTypes => break, // nowhere else to search
1905 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1906 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1907 /// `ident` in the first scope that defines it (or None if no scopes define it).
1909 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1910 /// the items are defined in the block. For example,
1913 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1916 /// g(); // This resolves to the local variable `g` since it shadows the item.
1920 /// Invariant: This must only be called during main resolution, not during
1921 /// import resolution.
1922 fn resolve_ident_in_lexical_scope(
1926 parent_scope: &ParentScope<'a>,
1927 record_used_id: Option<NodeId>,
1930 ) -> Option<LexicalScopeBinding<'a>> {
1931 assert!(ns == TypeNS || ns == ValueNS);
1932 let orig_ident = ident;
1933 if ident.name == kw::Empty {
1934 return Some(LexicalScopeBinding::Res(Res::Err));
1936 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1937 // FIXME(jseyfried) improve `Self` hygiene
1938 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1939 (empty_span, empty_span)
1940 } else if ns == TypeNS {
1941 let normalized_span = ident.span.normalize_to_macros_2_0();
1942 (normalized_span, normalized_span)
1944 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1946 ident.span = general_span;
1947 let normalized_ident = Ident { span: normalized_span, ..ident };
1949 // Walk backwards up the ribs in scope.
1950 let record_used = record_used_id.is_some();
1951 let mut module = self.graph_root;
1952 for i in (0..ribs.len()).rev() {
1953 debug!("walk rib\n{:?}", ribs[i].bindings);
1954 // Use the rib kind to determine whether we are resolving parameters
1955 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1956 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1957 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1959 // The ident resolves to a type parameter or local variable.
1960 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1966 *original_rib_ident_def,
1971 module = match ribs[i].kind {
1972 ModuleRibKind(module) => module,
1973 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1974 // If an invocation of this macro created `ident`, give up on `ident`
1975 // and switch to `ident`'s source from the macro definition.
1976 ident.span.remove_mark();
1983 ModuleKind::Block(..) => {} // We can see through blocks
1987 let item = self.resolve_ident_in_module_unadjusted(
1988 ModuleOrUniformRoot::Module(module),
1995 if let Ok(binding) = item {
1996 // The ident resolves to an item.
1997 return Some(LexicalScopeBinding::Item(binding));
2000 self.early_resolve_ident_in_lexical_scope(
2002 ScopeSet::Late(ns, module, record_used_id),
2009 .map(LexicalScopeBinding::Item)
2012 fn hygienic_lexical_parent(
2015 ctxt: &mut SyntaxContext,
2016 derive_fallback_lint_id: Option<NodeId>,
2017 ) -> Option<(Module<'a>, Option<NodeId>)> {
2018 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2019 return Some((self.macro_def_scope(ctxt.remove_mark()), None));
2022 if let ModuleKind::Block(..) = module.kind {
2023 return Some((module.parent.unwrap().nearest_item_scope(), None));
2026 // We need to support the next case under a deprecation warning
2029 // ---- begin: this comes from a proc macro derive
2030 // mod implementation_details {
2031 // // Note that `MyStruct` is not in scope here.
2032 // impl SomeTrait for MyStruct { ... }
2036 // So we have to fall back to the module's parent during lexical resolution in this case.
2037 if derive_fallback_lint_id.is_some() {
2038 if let Some(parent) = module.parent {
2039 // Inner module is inside the macro, parent module is outside of the macro.
2040 if module.expansion != parent.expansion
2041 && module.expansion.is_descendant_of(parent.expansion)
2043 // The macro is a proc macro derive
2044 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2045 let ext = self.get_macro_by_def_id(def_id);
2046 if ext.builtin_name.is_none()
2047 && ext.macro_kind() == MacroKind::Derive
2048 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2050 return Some((parent, derive_fallback_lint_id));
2060 fn resolve_ident_in_module(
2062 module: ModuleOrUniformRoot<'a>,
2065 parent_scope: &ParentScope<'a>,
2068 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2069 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2070 .map_err(|(determinacy, _)| determinacy)
2073 fn resolve_ident_in_module_ext(
2075 module: ModuleOrUniformRoot<'a>,
2078 parent_scope: &ParentScope<'a>,
2081 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2082 let tmp_parent_scope;
2083 let mut adjusted_parent_scope = parent_scope;
2085 ModuleOrUniformRoot::Module(m) => {
2086 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2088 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2089 adjusted_parent_scope = &tmp_parent_scope;
2092 ModuleOrUniformRoot::ExternPrelude => {
2093 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2095 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2099 self.resolve_ident_in_module_unadjusted_ext(
2103 adjusted_parent_scope,
2110 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2111 debug!("resolve_crate_root({:?})", ident);
2112 let mut ctxt = ident.span.ctxt();
2113 let mark = if ident.name == kw::DollarCrate {
2114 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2115 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2116 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2117 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2118 // definitions actually produced by `macro` and `macro` definitions produced by
2119 // `macro_rules!`, but at least such configurations are not stable yet.
2120 ctxt = ctxt.normalize_to_macro_rules();
2122 "resolve_crate_root: marks={:?}",
2123 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2125 let mut iter = ctxt.marks().into_iter().rev().peekable();
2126 let mut result = None;
2127 // Find the last opaque mark from the end if it exists.
2128 while let Some(&(mark, transparency)) = iter.peek() {
2129 if transparency == Transparency::Opaque {
2130 result = Some(mark);
2137 "resolve_crate_root: found opaque mark {:?} {:?}",
2139 result.map(|r| r.expn_data())
2141 // Then find the last semi-transparent mark from the end if it exists.
2142 for (mark, transparency) in iter {
2143 if transparency == Transparency::SemiTransparent {
2144 result = Some(mark);
2150 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2152 result.map(|r| r.expn_data())
2156 debug!("resolve_crate_root: not DollarCrate");
2157 ctxt = ctxt.normalize_to_macros_2_0();
2158 ctxt.adjust(ExpnId::root())
2160 let module = match mark {
2161 Some(def) => self.macro_def_scope(def),
2164 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2167 return self.graph_root;
2170 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2172 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2181 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2182 let mut module = self.get_module(module.nearest_parent_mod);
2183 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2184 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2185 module = self.get_module(parent.nearest_parent_mod);
2193 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2194 parent_scope: &ParentScope<'a>,
2197 crate_lint: CrateLint,
2198 ) -> PathResult<'a> {
2199 self.resolve_path_with_ribs(
2210 fn resolve_path_with_ribs(
2213 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2214 parent_scope: &ParentScope<'a>,
2217 crate_lint: CrateLint,
2218 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2219 ) -> PathResult<'a> {
2220 let mut module = None;
2221 let mut allow_super = true;
2222 let mut second_binding = None;
2225 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2226 path_span={:?}, crate_lint={:?})",
2227 path, opt_ns, record_used, path_span, crate_lint,
2230 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2231 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2232 let record_segment_res = |this: &mut Self, res| {
2234 if let Some(id) = id {
2235 if !this.partial_res_map.contains_key(&id) {
2236 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2237 this.record_partial_res(id, PartialRes::new(res));
2243 let is_last = i == path.len() - 1;
2244 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2245 let name = ident.name;
2247 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2250 if allow_super && name == kw::Super {
2251 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2252 let self_module = match i {
2253 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2255 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2259 if let Some(self_module) = self_module {
2260 if let Some(parent) = self_module.parent {
2261 module = Some(ModuleOrUniformRoot::Module(
2262 self.resolve_self(&mut ctxt, parent),
2267 let msg = "there are too many leading `super` keywords".to_string();
2268 return PathResult::Failed {
2272 is_error_from_last_segment: false,
2276 if name == kw::SelfLower {
2277 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2278 module = Some(ModuleOrUniformRoot::Module(
2279 self.resolve_self(&mut ctxt, parent_scope.module),
2283 if name == kw::PathRoot && ident.span.rust_2018() {
2284 module = Some(ModuleOrUniformRoot::ExternPrelude);
2287 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2288 // `::a::b` from 2015 macro on 2018 global edition
2289 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2292 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2293 // `::a::b`, `crate::a::b` or `$crate::a::b`
2294 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2300 // Report special messages for path segment keywords in wrong positions.
2301 if ident.is_path_segment_keyword() && i != 0 {
2302 let name_str = if name == kw::PathRoot {
2303 "crate root".to_string()
2305 format!("`{}`", name)
2307 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2308 format!("global paths cannot start with {}", name_str)
2310 format!("{} in paths can only be used in start position", name_str)
2312 return PathResult::Failed {
2316 is_error_from_last_segment: false,
2320 enum FindBindingResult<'a> {
2321 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2322 PathResult(PathResult<'a>),
2324 let find_binding_in_ns = |this: &mut Self, ns| {
2325 let binding = if let Some(module) = module {
2326 this.resolve_ident_in_module(
2334 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2335 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2336 this.early_resolve_ident_in_lexical_scope(
2345 let record_used_id = if record_used {
2346 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2350 match this.resolve_ident_in_lexical_scope(
2358 // we found a locally-imported or available item/module
2359 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2360 // we found a local variable or type param
2361 Some(LexicalScopeBinding::Res(res))
2362 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2364 record_segment_res(this, res);
2365 return FindBindingResult::PathResult(PathResult::NonModule(
2366 PartialRes::with_unresolved_segments(res, path.len() - 1),
2369 _ => Err(Determinacy::determined(record_used)),
2372 FindBindingResult::Binding(binding)
2374 let binding = match find_binding_in_ns(self, ns) {
2375 FindBindingResult::PathResult(x) => return x,
2376 FindBindingResult::Binding(binding) => binding,
2381 second_binding = Some(binding);
2383 let res = binding.res();
2384 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2385 if let Some(next_module) = binding.module() {
2386 module = Some(ModuleOrUniformRoot::Module(next_module));
2387 record_segment_res(self, res);
2388 } else if res == Res::ToolMod && i + 1 != path.len() {
2389 if binding.is_import() {
2393 "cannot use a tool module through an import",
2395 .span_note(binding.span, "the tool module imported here")
2398 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2399 return PathResult::NonModule(PartialRes::new(res));
2400 } else if res == Res::Err {
2401 return PathResult::NonModule(PartialRes::new(Res::Err));
2402 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2403 self.lint_if_path_starts_with_module(
2409 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2414 let label = format!(
2415 "`{}` is {} {}, not a module",
2421 return PathResult::Failed {
2425 is_error_from_last_segment: is_last,
2429 Err(Undetermined) => return PathResult::Indeterminate,
2430 Err(Determined) => {
2431 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2432 if opt_ns.is_some() && !module.is_normal() {
2433 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2434 module.res().unwrap(),
2439 let module_res = match module {
2440 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2443 let (label, suggestion) = if module_res == self.graph_root.res() {
2444 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2445 // Don't look up import candidates if this is a speculative resolve
2446 let mut candidates = if record_used {
2447 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2451 candidates.sort_by_cached_key(|c| {
2452 (c.path.segments.len(), pprust::path_to_string(&c.path))
2454 if let Some(candidate) = candidates.get(0) {
2456 String::from("unresolved import"),
2458 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2459 String::from("a similar path exists"),
2460 Applicability::MaybeIncorrect,
2463 } else if self.session.edition() == Edition::Edition2015 {
2464 (format!("maybe a missing crate `{}`?", ident), None)
2466 (format!("could not find `{}` in the crate root", ident), None)
2474 .map_or(false, |c| c.is_ascii_uppercase())
2476 // Check whether the name refers to an item in the value namespace.
2477 let suggestion = if ribs.is_some() {
2478 let match_span = match self.resolve_ident_in_lexical_scope(
2484 &ribs.unwrap()[ValueNS],
2486 // Name matches a local variable. For example:
2489 // let Foo: &str = "";
2490 // println!("{}", Foo::Bar); // Name refers to local
2491 // // variable `Foo`.
2494 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2495 Some(*self.pat_span_map.get(&id).unwrap())
2498 // Name matches item from a local name binding
2499 // created by `use` declaration. For example:
2501 // pub Foo: &str = "";
2505 // println!("{}", Foo::Bar); // Name refers to local
2506 // // binding `Foo`.
2509 Some(LexicalScopeBinding::Item(name_binding)) => {
2510 Some(name_binding.span)
2515 if let Some(span) = match_span {
2517 vec![(span, String::from(""))],
2518 format!("`{}` is defined here, but is not a type", ident),
2519 Applicability::MaybeIncorrect,
2528 (format!("use of undeclared type `{}`", ident), suggestion)
2530 (format!("use of undeclared crate or module `{}`", ident), None)
2533 let parent = path[i - 1].ident.name;
2534 let parent = match parent {
2535 // ::foo is mounted at the crate root for 2015, and is the extern
2536 // prelude for 2018+
2537 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2538 "the list of imported crates".to_owned()
2540 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2542 format!("`{}`", parent)
2546 let mut msg = format!("could not find `{}` in {}", ident, parent);
2547 if ns == TypeNS || ns == ValueNS {
2548 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2549 if let FindBindingResult::Binding(Ok(binding)) =
2550 find_binding_in_ns(self, ns_to_try)
2552 let mut found = |what| {
2554 "expected {}, found {} `{}` in {}",
2561 if binding.module().is_some() {
2564 match binding.res() {
2565 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2566 _ => found(ns_to_try.descr()),
2573 return PathResult::Failed {
2577 is_error_from_last_segment: is_last,
2583 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2585 PathResult::Module(match module {
2586 Some(module) => module,
2587 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2588 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2592 fn lint_if_path_starts_with_module(
2594 crate_lint: CrateLint,
2597 second_binding: Option<&NameBinding<'_>>,
2599 let (diag_id, diag_span) = match crate_lint {
2600 CrateLint::No => return,
2601 CrateLint::SimplePath(id) => (id, path_span),
2602 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2603 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2606 let first_name = match path.get(0) {
2607 // In the 2018 edition this lint is a hard error, so nothing to do
2608 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2612 // We're only interested in `use` paths which should start with
2613 // `{{root}}` currently.
2614 if first_name != kw::PathRoot {
2619 // If this import looks like `crate::...` it's already good
2620 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2621 // Otherwise go below to see if it's an extern crate
2623 // If the path has length one (and it's `PathRoot` most likely)
2624 // then we don't know whether we're gonna be importing a crate or an
2625 // item in our crate. Defer this lint to elsewhere
2629 // If the first element of our path was actually resolved to an
2630 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2631 // warning, this looks all good!
2632 if let Some(binding) = second_binding {
2633 if let NameBindingKind::Import { import, .. } = binding.kind {
2634 // Careful: we still want to rewrite paths from renamed extern crates.
2635 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2641 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2642 self.lint_buffer.buffer_lint_with_diagnostic(
2643 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2646 "absolute paths must start with `self`, `super`, \
2647 `crate`, or an external crate name in the 2018 edition",
2652 // Validate a local resolution (from ribs).
2653 fn validate_res_from_ribs(
2660 original_rib_ident_def: Ident,
2661 all_ribs: &[Rib<'a>],
2663 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2664 debug!("validate_res_from_ribs({:?})", res);
2665 let ribs = &all_ribs[rib_index + 1..];
2667 // An invalid forward use of a generic parameter from a previous default.
2668 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2670 let res_error = if rib_ident.name == kw::SelfUpper {
2671 ResolutionError::SelfInGenericParamDefault
2673 ResolutionError::ForwardDeclaredGenericParam
2675 self.report_error(span, res_error);
2677 assert_eq!(res, Res::Err);
2683 use ResolutionError::*;
2684 let mut res_err = None;
2689 | ClosureOrAsyncRibKind
2691 | MacroDefinition(..)
2692 | ForwardGenericParamBanRibKind => {
2693 // Nothing to do. Continue.
2695 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2696 // This was an attempt to access an upvar inside a
2697 // named function item. This is not allowed, so we
2700 // We don't immediately trigger a resolve error, because
2701 // we want certain other resolution errors (namely those
2702 // emitted for `ConstantItemRibKind` below) to take
2704 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2707 ConstantItemRibKind(_, item) => {
2708 // Still doesn't deal with upvars
2710 let (span, resolution_error) =
2711 if let Some((ident, constant_item_kind)) = item {
2712 let kind_str = match constant_item_kind {
2713 ConstantItemKind::Const => "const",
2714 ConstantItemKind::Static => "static",
2718 AttemptToUseNonConstantValueInConstant(
2719 ident, "let", kind_str,
2725 AttemptToUseNonConstantValueInConstant(
2726 original_rib_ident_def,
2732 self.report_error(span, resolution_error);
2736 ConstParamTyRibKind => {
2738 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2744 if let Some(res_err) = res_err {
2745 self.report_error(span, res_err);
2749 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2751 let has_generic_params: HasGenericParams = match rib.kind {
2753 | ClosureOrAsyncRibKind
2756 | MacroDefinition(..)
2757 | ForwardGenericParamBanRibKind => {
2758 // Nothing to do. Continue.
2762 ConstantItemRibKind(trivial, _) => {
2763 let features = self.session.features_untracked();
2764 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2765 if !(trivial || features.generic_const_exprs) {
2766 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2767 // we can't easily tell if it's generic at this stage, so we instead remember
2768 // this and then enforce the self type to be concrete later on.
2769 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2770 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2775 ResolutionError::ParamInNonTrivialAnonConst {
2776 name: rib_ident.name,
2782 self.session.delay_span_bug(span, CG_BUG_STR);
2790 // This was an attempt to use a type parameter outside its scope.
2791 ItemRibKind(has_generic_params) => has_generic_params,
2792 FnItemRibKind => HasGenericParams::Yes,
2793 ConstParamTyRibKind => {
2797 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2807 ResolutionError::GenericParamsFromOuterFunction(
2816 Res::Def(DefKind::ConstParam, _) => {
2817 let mut ribs = ribs.iter().peekable();
2818 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2819 // When declaring const parameters inside function signatures, the first rib
2820 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2821 // (spuriously) conflicting with the const param.
2826 let has_generic_params = match rib.kind {
2828 | ClosureOrAsyncRibKind
2831 | MacroDefinition(..)
2832 | ForwardGenericParamBanRibKind => continue,
2834 ConstantItemRibKind(trivial, _) => {
2835 let features = self.session.features_untracked();
2836 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2837 if !(trivial || features.generic_const_exprs) {
2841 ResolutionError::ParamInNonTrivialAnonConst {
2842 name: rib_ident.name,
2848 self.session.delay_span_bug(span, CG_BUG_STR);
2855 ItemRibKind(has_generic_params) => has_generic_params,
2856 FnItemRibKind => HasGenericParams::Yes,
2857 ConstParamTyRibKind => {
2861 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2868 // This was an attempt to use a const parameter outside its scope.
2872 ResolutionError::GenericParamsFromOuterFunction(
2886 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2887 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2888 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2889 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2893 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2894 debug!("(recording pat) recording {:?} for {:?}", node, span);
2895 self.pat_span_map.insert(node, span);
2898 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2899 vis.is_accessible_from(module.nearest_parent_mod, self)
2902 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2903 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2904 if !ptr::eq(module, old_module) {
2905 span_bug!(binding.span, "parent module is reset for binding");
2910 fn disambiguate_macro_rules_vs_modularized(
2912 macro_rules: &'a NameBinding<'a>,
2913 modularized: &'a NameBinding<'a>,
2915 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2916 // is disambiguated to mitigate regressions from macro modularization.
2917 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2919 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2920 self.binding_parent_modules.get(&PtrKey(modularized)),
2922 (Some(macro_rules), Some(modularized)) => {
2923 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2924 && modularized.is_ancestor_of(macro_rules)
2930 fn report_errors(&mut self, krate: &Crate) {
2931 self.report_with_use_injections(krate);
2933 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2934 let msg = "macro-expanded `macro_export` macros from the current crate \
2935 cannot be referred to by absolute paths";
2936 self.lint_buffer.buffer_lint_with_diagnostic(
2937 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2941 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2945 for ambiguity_error in &self.ambiguity_errors {
2946 self.report_ambiguity_error(ambiguity_error);
2949 let mut reported_spans = FxHashSet::default();
2950 for error in &self.privacy_errors {
2951 if reported_spans.insert(error.dedup_span) {
2952 self.report_privacy_error(error);
2957 fn report_with_use_injections(&mut self, krate: &Crate) {
2958 for UseError { mut err, candidates, def_id, instead, suggestion } in
2959 self.use_injections.drain(..)
2961 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2962 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2966 if !candidates.is_empty() {
2967 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2968 } else if let Some((span, msg, sugg, appl)) = suggestion {
2969 err.span_suggestion(span, msg, sugg, appl);
2975 fn report_conflict<'b>(
2980 new_binding: &NameBinding<'b>,
2981 old_binding: &NameBinding<'b>,
2983 // Error on the second of two conflicting names
2984 if old_binding.span.lo() > new_binding.span.lo() {
2985 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2988 let container = match parent.kind {
2989 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2990 ModuleKind::Block(..) => "block",
2993 let old_noun = match old_binding.is_import() {
2995 false => "definition",
2998 let new_participle = match new_binding.is_import() {
3004 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3006 if let Some(s) = self.name_already_seen.get(&name) {
3012 let old_kind = match (ns, old_binding.module()) {
3013 (ValueNS, _) => "value",
3014 (MacroNS, _) => "macro",
3015 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3016 (TypeNS, Some(module)) if module.is_normal() => "module",
3017 (TypeNS, Some(module)) if module.is_trait() => "trait",
3018 (TypeNS, _) => "type",
3021 let msg = format!("the name `{}` is defined multiple times", name);
3023 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3024 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3025 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3026 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3027 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3029 _ => match (old_binding.is_import(), new_binding.is_import()) {
3030 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3031 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3032 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3037 "`{}` must be defined only once in the {} namespace of this {}",
3043 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3045 self.session.source_map().guess_head_span(old_binding.span),
3046 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3049 // See https://github.com/rust-lang/rust/issues/32354
3050 use NameBindingKind::Import;
3051 let import = match (&new_binding.kind, &old_binding.kind) {
3052 // If there are two imports where one or both have attributes then prefer removing the
3053 // import without attributes.
3054 (Import { import: new, .. }, Import { import: old, .. })
3056 !new_binding.span.is_dummy()
3057 && !old_binding.span.is_dummy()
3058 && (new.has_attributes || old.has_attributes)
3061 if old.has_attributes {
3062 Some((new, new_binding.span, true))
3064 Some((old, old_binding.span, true))
3067 // Otherwise prioritize the new binding.
3068 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3069 Some((import, new_binding.span, other.is_import()))
3071 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3072 Some((import, old_binding.span, other.is_import()))
3077 // Check if the target of the use for both bindings is the same.
3078 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3079 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3081 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3082 // Only suggest removing an import if both bindings are to the same def, if both spans
3083 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3084 // been introduced by an item.
3085 let should_remove_import = duplicate
3087 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3090 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3091 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3093 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3094 // Simple case - remove the entire import. Due to the above match arm, this can
3095 // only be a single use so just remove it entirely.
3096 err.tool_only_span_suggestion(
3097 import.use_span_with_attributes,
3098 "remove unnecessary import",
3100 Applicability::MaybeIncorrect,
3103 Some((import, span, _)) => {
3104 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3110 self.name_already_seen.insert(name, span);
3113 /// This function adds a suggestion to change the binding name of a new import that conflicts
3114 /// with an existing import.
3116 /// ```text,ignore (diagnostic)
3117 /// help: you can use `as` to change the binding name of the import
3119 /// LL | use foo::bar as other_bar;
3120 /// | ^^^^^^^^^^^^^^^^^^^^^
3122 fn add_suggestion_for_rename_of_use(
3124 err: &mut DiagnosticBuilder<'_>,
3126 import: &Import<'_>,
3129 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3130 format!("Other{}", name)
3132 format!("other_{}", name)
3135 let mut suggestion = None;
3137 ImportKind::Single { type_ns_only: true, .. } => {
3138 suggestion = Some(format!("self as {}", suggested_name))
3140 ImportKind::Single { source, .. } => {
3142 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3144 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3145 if pos <= snippet.len() {
3146 suggestion = Some(format!(
3150 if snippet.ends_with(';') { ";" } else { "" }
3156 ImportKind::ExternCrate { source, target, .. } => {
3157 suggestion = Some(format!(
3158 "extern crate {} as {};",
3159 source.unwrap_or(target.name),
3163 _ => unreachable!(),
3166 let rename_msg = "you can use `as` to change the binding name of the import";
3167 if let Some(suggestion) = suggestion {
3168 err.span_suggestion(
3172 Applicability::MaybeIncorrect,
3175 err.span_label(binding_span, rename_msg);
3179 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3180 /// nested. In the following example, this function will be invoked to remove the `a` binding
3181 /// in the second use statement:
3183 /// ```ignore (diagnostic)
3184 /// use issue_52891::a;
3185 /// use issue_52891::{d, a, e};
3188 /// The following suggestion will be added:
3190 /// ```ignore (diagnostic)
3191 /// use issue_52891::{d, a, e};
3192 /// ^-- help: remove unnecessary import
3195 /// If the nested use contains only one import then the suggestion will remove the entire
3198 /// It is expected that the provided import is nested - this isn't checked by the
3199 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3200 /// as characters expected by span manipulations won't be present.
3201 fn add_suggestion_for_duplicate_nested_use(
3203 err: &mut DiagnosticBuilder<'_>,
3204 import: &Import<'_>,
3207 assert!(import.is_nested());
3208 let message = "remove unnecessary import";
3210 // Two examples will be used to illustrate the span manipulations we're doing:
3212 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3213 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3214 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3215 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3217 let (found_closing_brace, span) =
3218 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3220 // If there was a closing brace then identify the span to remove any trailing commas from
3221 // previous imports.
3222 if found_closing_brace {
3223 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3224 err.tool_only_span_suggestion(
3228 Applicability::MaybeIncorrect,
3231 // Remove the entire line if we cannot extend the span back, this indicates an
3232 // `issue_52891::{self}` case.
3233 err.span_suggestion(
3234 import.use_span_with_attributes,
3237 Applicability::MaybeIncorrect,
3244 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3247 fn extern_prelude_get(
3251 ) -> Option<&'a NameBinding<'a>> {
3252 if ident.is_path_segment_keyword() {
3253 // Make sure `self`, `super` etc produce an error when passed to here.
3256 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3257 if let Some(binding) = entry.extern_crate_item {
3258 if !speculative && entry.introduced_by_item {
3259 self.record_use(ident, binding, false);
3263 let crate_id = if !speculative {
3264 self.crate_loader.process_path_extern(ident.name, ident.span)
3266 self.crate_loader.maybe_process_path_extern(ident.name)?
3268 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3270 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3271 .to_name_binding(self.arenas),
3277 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3278 /// isn't something that can be returned because it can't be made to live that long,
3279 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3280 /// just that an error occurred.
3281 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3282 pub fn resolve_str_path_error(
3288 ) -> Result<(ast::Path, Res), ()> {
3289 let path = if path_str.starts_with("::") {
3292 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3293 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3294 .map(|i| self.new_ast_path_segment(i))
3303 .map(Ident::from_str)
3304 .map(|i| self.new_ast_path_segment(i))
3309 let module = self.get_module(module_id);
3310 let parent_scope = &ParentScope::module(module, self);
3311 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3315 // Resolve a path passed from rustdoc or HIR lowering.
3316 fn resolve_ast_path(
3320 parent_scope: &ParentScope<'a>,
3321 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3322 match self.resolve_path(
3323 &Segment::from_path(path),
3330 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3331 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3332 Ok(path_res.base_res())
3334 PathResult::NonModule(..) => Err((
3336 ResolutionError::FailedToResolve {
3337 label: String::from("type-relative paths are not supported in this context"),
3341 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3342 PathResult::Failed { span, label, suggestion, .. } => {
3343 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3348 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3349 let mut seg = ast::PathSegment::from_ident(ident);
3350 seg.id = self.next_node_id();
3355 pub fn graph_root(&self) -> Module<'a> {
3360 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3364 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3366 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3367 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3370 /// Checks if an expression refers to a function marked with
3371 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3372 /// from the attribute.
3373 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3374 if let ExprKind::Path(None, path) = &expr.kind {
3375 // Don't perform legacy const generics rewriting if the path already
3376 // has generic arguments.
3377 if path.segments.last().unwrap().args.is_some() {
3381 let partial_res = self.partial_res_map.get(&expr.id)?;
3382 if partial_res.unresolved_segments() != 0 {
3386 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3387 // We only support cross-crate argument rewriting. Uses
3388 // within the same crate should be updated to use the new
3389 // const generics style.
3390 if def_id.is_local() {
3394 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3398 let parse_attrs = || {
3399 let attrs = self.cstore().item_attrs(def_id, self.session);
3401 attrs.iter().find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3402 let mut ret = vec![];
3403 for meta in attr.meta_item_list()? {
3404 match meta.literal()?.kind {
3405 LitKind::Int(a, _) => {
3406 ret.push(a as usize);
3408 _ => panic!("invalid arg index"),
3414 // Cache the lookup to avoid parsing attributes for an iterm
3416 let ret = parse_attrs();
3417 self.legacy_const_generic_args.insert(def_id, ret.clone());
3424 fn resolve_main(&mut self) {
3425 let module = self.graph_root;
3426 let ident = Ident::with_dummy_span(sym::main);
3427 let parent_scope = &ParentScope::module(module, self);
3429 let name_binding = match self.resolve_ident_in_module(
3430 ModuleOrUniformRoot::Module(module),
3437 Ok(name_binding) => name_binding,
3441 let res = name_binding.res();
3442 let is_import = name_binding.is_import();
3443 let span = name_binding.span;
3444 if let Res::Def(DefKind::Fn, _) = res {
3445 self.record_use(ident, name_binding, false);
3447 self.main_def = Some(MainDefinition { res, is_import, span });
3451 fn names_to_string(names: &[Symbol]) -> String {
3452 let mut result = String::new();
3453 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3455 result.push_str("::");
3457 if Ident::with_dummy_span(*name).is_raw_guess() {
3458 result.push_str("r#");
3460 result.push_str(&name.as_str());
3465 fn path_names_to_string(path: &Path) -> String {
3466 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3469 /// A somewhat inefficient routine to obtain the name of a module.
3470 fn module_to_string(module: Module<'_>) -> Option<String> {
3471 let mut names = Vec::new();
3473 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3474 if let ModuleKind::Def(.., name) = module.kind {
3475 if let Some(parent) = module.parent {
3477 collect_mod(names, parent);
3480 names.push(Symbol::intern("<opaque>"));
3481 collect_mod(names, module.parent.unwrap());
3484 collect_mod(&mut names, module);
3486 if names.is_empty() {
3490 Some(names_to_string(&names))
3493 #[derive(Copy, Clone, Debug)]
3495 /// Do not issue the lint.
3498 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3499 /// In this case, we can take the span of that path.
3502 /// This lint comes from a `use` statement. In this case, what we
3503 /// care about really is the *root* `use` statement; e.g., if we
3504 /// have nested things like `use a::{b, c}`, we care about the
3506 UsePath { root_id: NodeId, root_span: Span },
3508 /// This is the "trait item" from a fully qualified path. For example,
3509 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3510 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3511 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3515 fn node_id(&self) -> Option<NodeId> {
3517 CrateLint::No => None,
3518 CrateLint::SimplePath(id)
3519 | CrateLint::UsePath { root_id: id, .. }
3520 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3525 pub fn provide(providers: &mut Providers) {
3526 late::lifetimes::provide(providers);