1 // ignore-tidy-filelength
3 //! This crate is responsible for the part of name resolution that doesn't require type checker.
5 //! Module structure of the crate is built here.
6 //! Paths in macros, imports, expressions, types, patterns are resolved here.
7 //! Label and lifetime names are resolved here as well.
9 //! Type-relative name resolution (methods, fields, associated items) happens in `rustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
12 #![feature(box_patterns)]
13 #![feature(drain_filter)]
14 #![feature(bool_to_option)]
15 #![feature(crate_visibility_modifier)]
16 #![feature(format_args_capture)]
18 #![feature(never_type)]
20 #![recursion_limit = "256"]
21 #![allow(rustdoc::private_intra_doc_links)]
26 pub use rustc_hir::def::{Namespace, PerNS};
30 use rustc_arena::{DroplessArena, TypedArena};
31 use rustc_ast::node_id::NodeMap;
32 use rustc_ast::ptr::P;
33 use rustc_ast::visit::{self, Visitor};
34 use rustc_ast::{self as ast, NodeId};
35 use rustc_ast::{Crate, CRATE_NODE_ID};
36 use rustc_ast::{Expr, ExprKind, LitKind};
37 use rustc_ast::{ItemKind, ModKind, Path};
38 use rustc_ast_lowering::ResolverAstLowering;
39 use rustc_ast_pretty::pprust;
40 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
41 use rustc_data_structures::ptr_key::PtrKey;
42 use rustc_data_structures::sync::Lrc;
43 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
44 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
45 use rustc_hir::def::Namespace::*;
46 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
47 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
48 use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
49 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
50 use rustc_hir::TraitCandidate;
51 use rustc_index::vec::IndexVec;
52 use rustc_metadata::creader::{CStore, CrateLoader};
53 use rustc_middle::hir::exports::ExportMap;
54 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
55 use rustc_middle::span_bug;
56 use rustc_middle::ty::query::Providers;
57 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
58 use rustc_session::lint;
59 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
60 use rustc_session::Session;
61 use rustc_span::edition::Edition;
62 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
63 use rustc_span::source_map::{CachingSourceMapView, Spanned};
64 use rustc_span::symbol::{kw, sym, Ident, Symbol};
65 use rustc_span::{Span, DUMMY_SP};
67 use smallvec::{smallvec, SmallVec};
68 use std::cell::{Cell, RefCell};
69 use std::collections::{BTreeMap, BTreeSet};
70 use std::ops::ControlFlow;
71 use std::{cmp, fmt, iter, ptr};
74 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
75 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
76 use imports::{Import, ImportKind, ImportResolver, NameResolution};
77 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
78 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
80 type Res = def::Res<NodeId>;
82 mod build_reduced_graph;
95 #[derive(Copy, Clone, PartialEq, Debug)]
96 pub enum Determinacy {
102 fn determined(determined: bool) -> Determinacy {
103 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
107 /// A specific scope in which a name can be looked up.
108 /// This enum is currently used only for early resolution (imports and macros),
109 /// but not for late resolution yet.
110 #[derive(Clone, Copy)]
112 DeriveHelpers(LocalExpnId),
114 MacroRules(MacroRulesScopeRef<'a>),
116 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
117 // lint if it should be reported.
118 Module(Module<'a>, Option<NodeId>),
128 /// Names from different contexts may want to visit different subsets of all specific scopes
129 /// with different restrictions when looking up the resolution.
130 /// This enum is currently used only for early resolution (imports and macros),
131 /// but not for late resolution yet.
132 #[derive(Clone, Copy)]
134 /// All scopes with the given namespace.
135 All(Namespace, /*is_import*/ bool),
136 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
137 AbsolutePath(Namespace),
138 /// All scopes with macro namespace and the given macro kind restriction.
140 /// All scopes with the given namespace, used for partially performing late resolution.
141 /// The node id enables lints and is used for reporting them.
142 Late(Namespace, Module<'a>, Option<NodeId>),
145 /// Everything you need to know about a name's location to resolve it.
146 /// Serves as a starting point for the scope visitor.
147 /// This struct is currently used only for early resolution (imports and macros),
148 /// but not for late resolution yet.
149 #[derive(Clone, Copy, Debug)]
150 pub struct ParentScope<'a> {
152 expansion: LocalExpnId,
153 macro_rules: MacroRulesScopeRef<'a>,
154 derives: &'a [ast::Path],
157 impl<'a> ParentScope<'a> {
158 /// Creates a parent scope with the passed argument used as the module scope component,
159 /// and other scope components set to default empty values.
160 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
163 expansion: LocalExpnId::ROOT,
164 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
170 #[derive(Copy, Debug, Clone)]
171 enum ImplTraitContext {
173 Universal(LocalDefId),
177 struct BindingError {
179 origin: BTreeSet<Span>,
180 target: BTreeSet<Span>,
184 impl PartialOrd for BindingError {
185 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
186 Some(self.cmp(other))
190 impl PartialEq for BindingError {
191 fn eq(&self, other: &BindingError) -> bool {
192 self.name == other.name
196 impl Ord for BindingError {
197 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
198 self.name.cmp(&other.name)
202 enum ResolutionError<'a> {
203 /// Error E0401: can't use type or const parameters from outer function.
204 GenericParamsFromOuterFunction(Res, HasGenericParams),
205 /// Error E0403: the name is already used for a type or const parameter in this generic
207 NameAlreadyUsedInParameterList(Symbol, Span),
208 /// Error E0407: method is not a member of trait.
209 MethodNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
210 /// Error E0437: type is not a member of trait.
211 TypeNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
212 /// Error E0438: const is not a member of trait.
213 ConstNotMemberOfTrait(Ident, &'a str, Option<Symbol>),
214 /// Error E0408: variable `{}` is not bound in all patterns.
215 VariableNotBoundInPattern(&'a BindingError),
216 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
217 VariableBoundWithDifferentMode(Symbol, Span),
218 /// Error E0415: identifier is bound more than once in this parameter list.
219 IdentifierBoundMoreThanOnceInParameterList(Symbol),
220 /// Error E0416: identifier is bound more than once in the same pattern.
221 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
222 /// Error E0426: use of undeclared label.
223 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
224 /// Error E0429: `self` imports are only allowed within a `{ }` list.
225 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
226 /// Error E0430: `self` import can only appear once in the list.
227 SelfImportCanOnlyAppearOnceInTheList,
228 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
229 SelfImportOnlyInImportListWithNonEmptyPrefix,
230 /// Error E0433: failed to resolve.
231 FailedToResolve { label: String, suggestion: Option<Suggestion> },
232 /// Error E0434: can't capture dynamic environment in a fn item.
233 CannotCaptureDynamicEnvironmentInFnItem,
234 /// Error E0435: attempt to use a non-constant value in a constant.
235 AttemptToUseNonConstantValueInConstant(
237 /* suggestion */ &'static str,
238 /* current */ &'static str,
240 /// Error E0530: `X` bindings cannot shadow `Y`s.
241 BindingShadowsSomethingUnacceptable {
242 shadowing_binding_descr: &'static str,
244 participle: &'static str,
245 article: &'static str,
246 shadowed_binding_descr: &'static str,
247 shadowed_binding_span: Span,
249 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
250 ForwardDeclaredGenericParam,
251 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
252 ParamInTyOfConstParam(Symbol),
253 /// generic parameters must not be used inside const evaluations.
255 /// This error is only emitted when using `min_const_generics`.
256 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
257 /// Error E0735: generic parameters with a default cannot use `Self`
258 SelfInGenericParamDefault,
259 /// Error E0767: use of unreachable label
260 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
263 enum VisResolutionError<'a> {
264 Relative2018(Span, &'a ast::Path),
266 FailedToResolve(Span, String, Option<Suggestion>),
267 ExpectedFound(Span, String, Res),
272 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
273 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
274 #[derive(Clone, Copy, Debug)]
278 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
279 /// nonsensical suggestions.
280 has_generic_args: bool,
284 fn from_path(path: &Path) -> Vec<Segment> {
285 path.segments.iter().map(|s| s.into()).collect()
288 fn from_ident(ident: Ident) -> Segment {
289 Segment { ident, id: None, has_generic_args: false }
292 fn names_to_string(segments: &[Segment]) -> String {
293 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
297 impl<'a> From<&'a ast::PathSegment> for Segment {
298 fn from(seg: &'a ast::PathSegment) -> Segment {
299 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
303 struct UsePlacementFinder {
304 target_module: NodeId,
309 impl UsePlacementFinder {
310 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
311 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
312 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
313 visit::walk_crate(&mut finder, krate);
315 (finder.span, finder.found_use)
318 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
319 if self.span.is_some() {
320 return ControlFlow::Break(());
322 if node_id != self.target_module {
323 return ControlFlow::Continue(());
325 // find a use statement
328 ItemKind::Use(..) => {
329 // don't suggest placing a use before the prelude
330 // import or other generated ones
331 if !item.span.from_expansion() {
332 self.span = Some(item.span.shrink_to_lo());
333 self.found_use = true;
334 return ControlFlow::Break(());
337 // don't place use before extern crate
338 ItemKind::ExternCrate(_) => {}
339 // but place them before the first other item
341 if self.span.map_or(true, |span| item.span < span)
342 && !item.span.from_expansion()
344 self.span = Some(item.span.shrink_to_lo());
345 // don't insert between attributes and an item
346 // find the first attribute on the item
347 // FIXME: This is broken for active attributes.
348 for attr in &item.attrs {
349 if !attr.span.is_dummy()
350 && self.span.map_or(true, |span| attr.span < span)
352 self.span = Some(attr.span.shrink_to_lo());
359 ControlFlow::Continue(())
363 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
364 fn visit_item(&mut self, item: &'tcx ast::Item) {
365 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
366 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
370 visit::walk_item(self, item);
374 /// An intermediate resolution result.
376 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
377 /// items are visible in their whole block, while `Res`es only from the place they are defined
380 enum LexicalScopeBinding<'a> {
381 Item(&'a NameBinding<'a>),
385 impl<'a> LexicalScopeBinding<'a> {
386 fn res(self) -> Res {
388 LexicalScopeBinding::Item(binding) => binding.res(),
389 LexicalScopeBinding::Res(res) => res,
394 #[derive(Copy, Clone, Debug)]
395 enum ModuleOrUniformRoot<'a> {
399 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
400 CrateRootAndExternPrelude,
402 /// Virtual module that denotes resolution in extern prelude.
403 /// Used for paths starting with `::` on 2018 edition.
406 /// Virtual module that denotes resolution in current scope.
407 /// Used only for resolving single-segment imports. The reason it exists is that import paths
408 /// are always split into two parts, the first of which should be some kind of module.
412 impl ModuleOrUniformRoot<'_> {
413 fn same_def(lhs: Self, rhs: Self) -> bool {
415 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
419 ModuleOrUniformRoot::CrateRootAndExternPrelude,
420 ModuleOrUniformRoot::CrateRootAndExternPrelude,
422 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
423 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
429 #[derive(Clone, Debug)]
430 enum PathResult<'a> {
431 Module(ModuleOrUniformRoot<'a>),
432 NonModule(PartialRes),
437 suggestion: Option<Suggestion>,
438 is_error_from_last_segment: bool,
444 /// An anonymous module; e.g., just a block.
449 /// { // This is an anonymous module
450 /// f(); // This resolves to (2) as we are inside the block.
453 /// f(); // Resolves to (1)
457 /// Any module with a name.
461 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
462 /// or the crate root (which is conceptually a top-level module).
463 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
464 /// * A trait or an enum (it implicitly contains associated types, methods and variant
466 Def(DefKind, DefId, Symbol),
470 /// Get name of the module.
471 pub fn name(&self) -> Option<Symbol> {
473 ModuleKind::Block(..) => None,
474 ModuleKind::Def(.., name) => Some(*name),
479 /// A key that identifies a binding in a given `Module`.
481 /// Multiple bindings in the same module can have the same key (in a valid
482 /// program) if all but one of them come from glob imports.
483 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
485 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
489 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
490 /// `_` in the expanded AST that introduced this binding.
494 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
496 /// One node in the tree of modules.
498 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
501 /// * crate root (aka, top-level anonymous module)
504 /// * curly-braced block with statements
506 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
507 pub struct ModuleData<'a> {
508 /// The direct parent module (it may not be a `mod`, however).
509 parent: Option<Module<'a>>,
510 /// What kind of module this is, because this may not be a `mod`.
513 /// Mapping between names and their (possibly in-progress) resolutions in this module.
514 /// Resolutions in modules from other crates are not populated until accessed.
515 lazy_resolutions: Resolutions<'a>,
516 /// True if this is a module from other crate that needs to be populated on access.
517 populate_on_access: Cell<bool>,
519 /// Macro invocations that can expand into items in this module.
520 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
522 /// Whether `#[no_implicit_prelude]` is active.
523 no_implicit_prelude: bool,
525 glob_importers: RefCell<Vec<&'a Import<'a>>>,
526 globs: RefCell<Vec<&'a Import<'a>>>,
528 /// Used to memoize the traits in this module for faster searches through all traits in scope.
529 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
531 /// Span of the module itself. Used for error reporting.
537 type Module<'a> = &'a ModuleData<'a>;
539 impl<'a> ModuleData<'a> {
541 parent: Option<Module<'a>>,
545 no_implicit_prelude: bool,
547 let is_foreign = match kind {
548 ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
549 ModuleKind::Block(_) => false,
554 lazy_resolutions: Default::default(),
555 populate_on_access: Cell::new(is_foreign),
556 unexpanded_invocations: Default::default(),
558 glob_importers: RefCell::new(Vec::new()),
559 globs: RefCell::new(Vec::new()),
560 traits: RefCell::new(None),
566 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
568 R: AsMut<Resolver<'a>>,
569 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
571 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
572 if let Some(binding) = name_resolution.borrow().binding {
573 f(resolver, key.ident, key.ns, binding);
578 /// This modifies `self` in place. The traits will be stored in `self.traits`.
579 fn ensure_traits<R>(&'a self, resolver: &mut R)
581 R: AsMut<Resolver<'a>>,
583 let mut traits = self.traits.borrow_mut();
584 if traits.is_none() {
585 let mut collected_traits = Vec::new();
586 self.for_each_child(resolver, |_, name, ns, binding| {
590 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
591 collected_traits.push((name, binding))
594 *traits = Some(collected_traits.into_boxed_slice());
598 fn res(&self) -> Option<Res> {
600 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
605 fn def_id(&self) -> DefId {
606 self.opt_def_id().expect("`ModuleData::def_id` is called on a block module")
609 fn opt_def_id(&self) -> Option<DefId> {
611 ModuleKind::Def(_, def_id, _) => Some(def_id),
616 // `self` resolves to the first module ancestor that `is_normal`.
617 fn is_normal(&self) -> bool {
618 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
621 fn is_trait(&self) -> bool {
622 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
625 fn nearest_item_scope(&'a self) -> Module<'a> {
627 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
628 self.parent.expect("enum or trait module without a parent")
634 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
635 /// This may be the crate root.
636 fn nearest_parent_mod(&self) -> DefId {
638 ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
639 _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
643 fn is_ancestor_of(&self, mut other: &Self) -> bool {
644 while !ptr::eq(self, other) {
645 if let Some(parent) = other.parent {
655 impl<'a> fmt::Debug for ModuleData<'a> {
656 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
657 write!(f, "{:?}", self.res())
661 /// Records a possibly-private value, type, or module definition.
662 #[derive(Clone, Debug)]
663 pub struct NameBinding<'a> {
664 kind: NameBindingKind<'a>,
665 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
666 expansion: LocalExpnId,
671 pub trait ToNameBinding<'a> {
672 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
675 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
676 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
681 #[derive(Clone, Debug)]
682 enum NameBindingKind<'a> {
683 Res(Res, /* is_macro_export */ bool),
685 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
688 impl<'a> NameBindingKind<'a> {
689 /// Is this a name binding of an import?
690 fn is_import(&self) -> bool {
691 matches!(*self, NameBindingKind::Import { .. })
695 struct PrivacyError<'a> {
697 binding: &'a NameBinding<'a>,
701 struct UseError<'a> {
702 err: DiagnosticBuilder<'a>,
703 /// Candidates which user could `use` to access the missing type.
704 candidates: Vec<ImportSuggestion>,
705 /// The `DefId` of the module to place the use-statements in.
707 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
709 /// Extra free-form suggestion.
710 suggestion: Option<(Span, &'static str, String, Applicability)>,
713 #[derive(Clone, Copy, PartialEq, Debug)]
718 MacroRulesVsModularized,
726 fn descr(self) -> &'static str {
728 AmbiguityKind::Import => "name vs any other name during import resolution",
729 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
730 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
731 AmbiguityKind::MacroRulesVsModularized => {
732 "`macro_rules` vs non-`macro_rules` from other module"
734 AmbiguityKind::GlobVsOuter => {
735 "glob import vs any other name from outer scope during import/macro resolution"
737 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
738 AmbiguityKind::GlobVsExpanded => {
739 "glob import vs macro-expanded name in the same \
740 module during import/macro resolution"
742 AmbiguityKind::MoreExpandedVsOuter => {
743 "macro-expanded name vs less macro-expanded name \
744 from outer scope during import/macro resolution"
750 /// Miscellaneous bits of metadata for better ambiguity error reporting.
751 #[derive(Clone, Copy, PartialEq)]
752 enum AmbiguityErrorMisc {
759 struct AmbiguityError<'a> {
762 b1: &'a NameBinding<'a>,
763 b2: &'a NameBinding<'a>,
764 misc1: AmbiguityErrorMisc,
765 misc2: AmbiguityErrorMisc,
768 impl<'a> NameBinding<'a> {
769 fn module(&self) -> Option<Module<'a>> {
771 NameBindingKind::Module(module) => Some(module),
772 NameBindingKind::Import { binding, .. } => binding.module(),
777 fn res(&self) -> Res {
779 NameBindingKind::Res(res, _) => res,
780 NameBindingKind::Module(module) => module.res().unwrap(),
781 NameBindingKind::Import { binding, .. } => binding.res(),
785 fn is_ambiguity(&self) -> bool {
786 self.ambiguity.is_some()
788 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
793 fn is_possibly_imported_variant(&self) -> bool {
795 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
796 NameBindingKind::Res(
797 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
800 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
804 fn is_extern_crate(&self) -> bool {
806 NameBindingKind::Import {
807 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
810 NameBindingKind::Module(&ModuleData {
811 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
813 }) => def_id.index == CRATE_DEF_INDEX,
818 fn is_import(&self) -> bool {
819 matches!(self.kind, NameBindingKind::Import { .. })
822 fn is_glob_import(&self) -> bool {
824 NameBindingKind::Import { import, .. } => import.is_glob(),
829 fn is_importable(&self) -> bool {
832 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
836 fn is_macro_def(&self) -> bool {
837 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
840 fn macro_kind(&self) -> Option<MacroKind> {
841 self.res().macro_kind()
844 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
845 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
846 // Then this function returns `true` if `self` may emerge from a macro *after* that
847 // in some later round and screw up our previously found resolution.
848 // See more detailed explanation in
849 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
852 invoc_parent_expansion: LocalExpnId,
853 binding: &NameBinding<'_>,
855 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
856 // Expansions are partially ordered, so "may appear after" is an inversion of
857 // "certainly appears before or simultaneously" and includes unordered cases.
858 let self_parent_expansion = self.expansion;
859 let other_parent_expansion = binding.expansion;
860 let certainly_before_other_or_simultaneously =
861 other_parent_expansion.is_descendant_of(self_parent_expansion);
862 let certainly_before_invoc_or_simultaneously =
863 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
864 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
868 #[derive(Debug, Default, Clone)]
869 pub struct ExternPreludeEntry<'a> {
870 extern_crate_item: Option<&'a NameBinding<'a>>,
871 pub introduced_by_item: bool,
874 /// Used for better errors for E0773
875 enum BuiltinMacroState {
876 NotYetSeen(SyntaxExtensionKind),
881 resolutions: DeriveResolutions,
882 helper_attrs: Vec<(usize, Ident)>,
883 has_derive_copy: bool,
886 /// The main resolver class.
888 /// This is the visitor that walks the whole crate.
889 pub struct Resolver<'a> {
890 session: &'a Session,
892 definitions: Definitions,
894 graph_root: Module<'a>,
896 prelude: Option<Module<'a>>,
897 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
899 /// N.B., this is used only for better diagnostics, not name resolution itself.
900 has_self: FxHashSet<DefId>,
902 /// Names of fields of an item `DefId` accessible with dot syntax.
903 /// Used for hints during error reporting.
904 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
906 /// All imports known to succeed or fail.
907 determined_imports: Vec<&'a Import<'a>>,
909 /// All non-determined imports.
910 indeterminate_imports: Vec<&'a Import<'a>>,
912 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
913 /// We are resolving a last import segment during import validation.
914 last_import_segment: bool,
915 /// This binding should be ignored during in-module resolution, so that we don't get
916 /// "self-confirming" import resolutions during import validation.
917 unusable_binding: Option<&'a NameBinding<'a>>,
919 // Spans for local variables found during pattern resolution.
920 // Used for suggestions during error reporting.
921 pat_span_map: NodeMap<Span>,
923 /// Resolutions for nodes that have a single resolution.
924 partial_res_map: NodeMap<PartialRes>,
925 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
926 import_res_map: NodeMap<PerNS<Option<Res>>>,
927 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
928 label_res_map: NodeMap<NodeId>,
930 /// `CrateNum` resolutions of `extern crate` items.
931 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
932 export_map: ExportMap,
933 trait_map: Option<NodeMap<Vec<TraitCandidate>>>,
935 /// A map from nodes to anonymous modules.
936 /// Anonymous modules are pseudo-modules that are implicitly created around items
937 /// contained within blocks.
939 /// For example, if we have this:
947 /// There will be an anonymous module created around `g` with the ID of the
948 /// entry block for `f`.
949 block_map: NodeMap<Module<'a>>,
950 /// A fake module that contains no definition and no prelude. Used so that
951 /// some AST passes can generate identifiers that only resolve to local or
953 empty_module: Module<'a>,
954 module_map: FxHashMap<DefId, Module<'a>>,
955 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
956 underscore_disambiguator: u32,
958 /// Maps glob imports to the names of items actually imported.
959 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
960 /// Visibilities in "lowered" form, for all entities that have them.
961 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
962 used_imports: FxHashSet<NodeId>,
963 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
964 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
966 /// Privacy errors are delayed until the end in order to deduplicate them.
967 privacy_errors: Vec<PrivacyError<'a>>,
968 /// Ambiguity errors are delayed for deduplication.
969 ambiguity_errors: Vec<AmbiguityError<'a>>,
970 /// `use` injections are delayed for better placement and deduplication.
971 use_injections: Vec<UseError<'a>>,
972 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
973 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
975 arenas: &'a ResolverArenas<'a>,
976 dummy_binding: &'a NameBinding<'a>,
978 crate_loader: CrateLoader<'a>,
979 macro_names: FxHashSet<Ident>,
980 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
981 registered_attrs: FxHashSet<Ident>,
982 registered_tools: FxHashSet<Ident>,
983 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
984 all_macros: FxHashMap<Symbol, Res>,
985 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
986 dummy_ext_bang: Lrc<SyntaxExtension>,
987 dummy_ext_derive: Lrc<SyntaxExtension>,
988 non_macro_attr: Lrc<SyntaxExtension>,
989 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
990 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
991 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
992 proc_macro_stubs: FxHashSet<LocalDefId>,
993 /// Traces collected during macro resolution and validated when it's complete.
994 single_segment_macro_resolutions:
995 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
996 multi_segment_macro_resolutions:
997 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
998 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
999 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
1000 /// Derive macros cannot modify the item themselves and have to store the markers in the global
1001 /// context, so they attach the markers to derive container IDs using this resolver table.
1002 containers_deriving_copy: FxHashSet<LocalExpnId>,
1003 /// Parent scopes in which the macros were invoked.
1004 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
1005 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
1006 /// `macro_rules` scopes *produced* by expanding the macro invocations,
1007 /// include all the `macro_rules` items and other invocations generated by them.
1008 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
1009 /// Helper attributes that are in scope for the given expansion.
1010 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
1011 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
1012 /// with the given `ExpnId`.
1013 derive_data: FxHashMap<LocalExpnId, DeriveData>,
1015 /// Avoid duplicated errors for "name already defined".
1016 name_already_seen: FxHashMap<Symbol, Span>,
1018 potentially_unused_imports: Vec<&'a Import<'a>>,
1020 /// Table for mapping struct IDs into struct constructor IDs,
1021 /// it's not used during normal resolution, only for better error reporting.
1022 /// Also includes of list of each fields visibility
1023 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1025 /// Features enabled for this crate.
1026 active_features: FxHashSet<Symbol>,
1028 lint_buffer: LintBuffer,
1030 next_node_id: NodeId,
1032 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1033 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1035 /// Indices of unnamed struct or variant fields with unresolved attributes.
1036 placeholder_field_indices: FxHashMap<NodeId, usize>,
1037 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1038 /// we know what parent node that fragment should be attached to thanks to this table,
1039 /// and how the `impl Trait` fragments were introduced.
1040 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1042 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1043 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1044 /// FIXME: Replace with a more general AST map (together with some other fields).
1045 trait_impl_items: FxHashSet<LocalDefId>,
1047 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1048 /// Amount of lifetime parameters for each item in the crate.
1049 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1051 main_def: Option<MainDefinition>,
1052 trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
1053 /// A list of proc macro LocalDefIds, written out in the order in which
1054 /// they are declared in the static array generated by proc_macro_harness.
1055 proc_macros: Vec<NodeId>,
1056 confused_type_with_std_module: FxHashMap<Span, Span>,
1059 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1061 pub struct ResolverArenas<'a> {
1062 modules: TypedArena<ModuleData<'a>>,
1063 local_modules: RefCell<Vec<Module<'a>>>,
1064 imports: TypedArena<Import<'a>>,
1065 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1066 ast_paths: TypedArena<ast::Path>,
1067 dropless: DroplessArena,
1070 impl<'a> ResolverArenas<'a> {
1073 parent: Option<Module<'a>>,
1077 no_implicit_prelude: bool,
1078 module_map: &mut FxHashMap<DefId, Module<'a>>,
1081 self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude));
1082 let def_id = module.opt_def_id();
1083 if def_id.map_or(true, |def_id| def_id.is_local()) {
1084 self.local_modules.borrow_mut().push(module);
1086 if let Some(def_id) = def_id {
1087 module_map.insert(def_id, module);
1091 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1092 self.local_modules.borrow()
1094 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1095 self.dropless.alloc(name_binding)
1097 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1098 self.imports.alloc(import)
1100 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1101 self.name_resolutions.alloc(Default::default())
1103 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1104 PtrKey(self.dropless.alloc(Cell::new(scope)))
1106 fn alloc_macro_rules_binding(
1108 binding: MacroRulesBinding<'a>,
1109 ) -> &'a MacroRulesBinding<'a> {
1110 self.dropless.alloc(binding)
1112 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1113 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1115 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1116 self.dropless.alloc_from_iter(spans)
1120 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1121 fn as_mut(&mut self) -> &mut Resolver<'a> {
1126 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1127 fn parent(self, id: DefId) -> Option<DefId> {
1128 match id.as_local() {
1129 Some(id) => self.definitions.def_key(id).parent,
1130 None => self.cstore().def_key(id).parent,
1132 .map(|index| DefId { index, ..id })
1136 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1137 /// the resolver is no longer needed as all the relevant information is inline.
1138 impl ResolverAstLowering for Resolver<'_> {
1139 fn def_key(&mut self, id: DefId) -> DefKey {
1140 if let Some(id) = id.as_local() {
1141 self.definitions().def_key(id)
1143 self.cstore().def_key(id)
1148 fn def_span(&self, id: LocalDefId) -> Span {
1149 self.definitions.def_span(id)
1152 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1153 if let Some(def_id) = def_id.as_local() {
1154 self.item_generics_num_lifetimes[&def_id]
1156 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1160 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1161 self.legacy_const_generic_args(expr)
1164 fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
1165 self.partial_res_map.get(&id).cloned()
1168 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1169 self.import_res_map.get(&id).cloned().unwrap_or_default()
1172 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1173 self.label_res_map.get(&id).cloned()
1176 fn definitions(&mut self) -> &mut Definitions {
1177 &mut self.definitions
1180 fn lint_buffer(&mut self) -> &mut LintBuffer {
1181 &mut self.lint_buffer
1184 fn next_node_id(&mut self) -> NodeId {
1188 fn take_trait_map(&mut self) -> NodeMap<Vec<TraitCandidate>> {
1189 std::mem::replace(&mut self.trait_map, None).unwrap()
1192 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1193 self.node_id_to_def_id.get(&node).copied()
1196 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1197 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1200 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1201 match def_id.as_local() {
1202 Some(def_id) => self.definitions.def_path_hash(def_id),
1203 None => self.cstore().def_path_hash(def_id),
1207 /// Adds a definition with a parent definition.
1211 node_id: ast::NodeId,
1217 !self.node_id_to_def_id.contains_key(&node_id),
1218 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1221 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1224 // Find the next free disambiguator for this key.
1225 let next_disambiguator = &mut self.next_disambiguator;
1226 let next_disambiguator = |parent, data| {
1227 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1228 let disambiguator = *next_disamb;
1229 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1233 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1235 // Some things for which we allocate `LocalDefId`s don't correspond to
1236 // anything in the AST, so they don't have a `NodeId`. For these cases
1237 // we don't need a mapping from `NodeId` to `LocalDefId`.
1238 if node_id != ast::DUMMY_NODE_ID {
1239 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1240 self.node_id_to_def_id.insert(node_id, def_id);
1242 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1248 struct ExpandHasher<'a, 'b> {
1249 source_map: CachingSourceMapView<'a>,
1250 resolver: &'a Resolver<'b>,
1253 impl<'a, 'b> rustc_span::HashStableContext for ExpandHasher<'a, 'b> {
1255 fn hash_spans(&self) -> bool {
1260 fn def_span(&self, id: LocalDefId) -> Span {
1261 self.resolver.def_span(id)
1265 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1266 self.resolver.def_path_hash(def_id)
1270 fn span_data_to_lines_and_cols(
1272 span: &rustc_span::SpanData,
1273 ) -> Option<(Lrc<rustc_span::SourceFile>, usize, rustc_span::BytePos, usize, rustc_span::BytePos)>
1275 self.source_map.span_data_to_lines_and_cols(span)
1279 impl<'a> Resolver<'a> {
1281 session: &'a Session,
1284 metadata_loader: Box<MetadataLoaderDyn>,
1285 arenas: &'a ResolverArenas<'a>,
1287 let root_def_id = CRATE_DEF_ID.to_def_id();
1288 let mut module_map = FxHashMap::default();
1289 let graph_root = arenas.new_module(
1291 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1294 session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1297 let empty_module = arenas.new_module(
1299 ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty),
1303 &mut FxHashMap::default(),
1306 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1307 let root = definitions.get_root_def();
1309 let mut visibilities = FxHashMap::default();
1310 visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
1312 let mut def_id_to_node_id = IndexVec::default();
1313 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1314 let mut node_id_to_def_id = FxHashMap::default();
1315 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1317 let mut invocation_parents = FxHashMap::default();
1318 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1320 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1324 .filter(|(_, entry)| entry.add_prelude)
1325 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1328 if !session.contains_name(&krate.attrs, sym::no_core) {
1329 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1330 if !session.contains_name(&krate.attrs, sym::no_std) {
1331 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1335 let (registered_attrs, registered_tools) =
1336 macros::registered_attrs_and_tools(session, &krate.attrs);
1338 let features = session.features_untracked();
1340 let mut resolver = Resolver {
1345 // The outermost module has def ID 0; this is not reflected in the
1351 has_self: FxHashSet::default(),
1352 field_names: FxHashMap::default(),
1354 determined_imports: Vec::new(),
1355 indeterminate_imports: Vec::new(),
1357 last_import_segment: false,
1358 unusable_binding: None,
1360 pat_span_map: Default::default(),
1361 partial_res_map: Default::default(),
1362 import_res_map: Default::default(),
1363 label_res_map: Default::default(),
1364 extern_crate_map: Default::default(),
1365 export_map: FxHashMap::default(),
1366 trait_map: Some(NodeMap::default()),
1367 underscore_disambiguator: 0,
1370 block_map: Default::default(),
1371 binding_parent_modules: FxHashMap::default(),
1372 ast_transform_scopes: FxHashMap::default(),
1374 glob_map: Default::default(),
1376 used_imports: FxHashSet::default(),
1377 maybe_unused_trait_imports: Default::default(),
1378 maybe_unused_extern_crates: Vec::new(),
1380 privacy_errors: Vec::new(),
1381 ambiguity_errors: Vec::new(),
1382 use_injections: Vec::new(),
1383 macro_expanded_macro_export_errors: BTreeSet::new(),
1386 dummy_binding: arenas.alloc_name_binding(NameBinding {
1387 kind: NameBindingKind::Res(Res::Err, false),
1389 expansion: LocalExpnId::ROOT,
1391 vis: ty::Visibility::Public,
1394 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1395 macro_names: FxHashSet::default(),
1396 builtin_macros: Default::default(),
1399 macro_use_prelude: FxHashMap::default(),
1400 all_macros: FxHashMap::default(),
1401 macro_map: FxHashMap::default(),
1402 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1403 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1404 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1405 invocation_parent_scopes: Default::default(),
1406 output_macro_rules_scopes: Default::default(),
1407 helper_attrs: Default::default(),
1408 derive_data: Default::default(),
1409 local_macro_def_scopes: FxHashMap::default(),
1410 name_already_seen: FxHashMap::default(),
1411 potentially_unused_imports: Vec::new(),
1412 struct_constructors: Default::default(),
1413 unused_macros: Default::default(),
1414 proc_macro_stubs: Default::default(),
1415 single_segment_macro_resolutions: Default::default(),
1416 multi_segment_macro_resolutions: Default::default(),
1417 builtin_attrs: Default::default(),
1418 containers_deriving_copy: Default::default(),
1419 active_features: features
1420 .declared_lib_features
1422 .map(|(feat, ..)| *feat)
1423 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1425 lint_buffer: LintBuffer::default(),
1426 next_node_id: NodeId::from_u32(1),
1429 placeholder_field_indices: Default::default(),
1431 next_disambiguator: Default::default(),
1432 trait_impl_items: Default::default(),
1433 legacy_const_generic_args: Default::default(),
1434 item_generics_num_lifetimes: Default::default(),
1435 main_def: Default::default(),
1436 trait_impls: Default::default(),
1437 proc_macros: Default::default(),
1438 confused_type_with_std_module: Default::default(),
1441 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1442 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1449 parent: Option<Module<'a>>,
1453 no_implicit_prelude: bool,
1455 let module_map = &mut self.module_map;
1456 self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map)
1459 fn create_stable_hashing_context(&self) -> ExpandHasher<'_, 'a> {
1461 source_map: CachingSourceMapView::new(self.session.source_map()),
1466 pub fn next_node_id(&mut self) -> NodeId {
1471 .expect("input too large; ran out of NodeIds");
1472 self.next_node_id = ast::NodeId::from_usize(next);
1476 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1477 &mut self.lint_buffer
1480 pub fn arenas() -> ResolverArenas<'a> {
1484 pub fn into_outputs(self) -> ResolverOutputs {
1485 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1486 let definitions = self.definitions;
1487 let visibilities = self.visibilities;
1488 let extern_crate_map = self.extern_crate_map;
1489 let export_map = self.export_map;
1490 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1491 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1492 let glob_map = self.glob_map;
1493 let main_def = self.main_def;
1494 let confused_type_with_std_module = self.confused_type_with_std_module;
1497 cstore: Box::new(self.crate_loader.into_cstore()),
1502 maybe_unused_trait_imports,
1503 maybe_unused_extern_crates,
1504 extern_prelude: self
1507 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1510 trait_impls: self.trait_impls,
1512 confused_type_with_std_module,
1516 pub fn clone_outputs(&self) -> ResolverOutputs {
1517 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1519 definitions: self.definitions.clone(),
1520 cstore: Box::new(self.cstore().clone()),
1521 visibilities: self.visibilities.clone(),
1522 extern_crate_map: self.extern_crate_map.clone(),
1523 export_map: self.export_map.clone(),
1524 glob_map: self.glob_map.clone(),
1525 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1526 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1527 extern_prelude: self
1530 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1532 main_def: self.main_def,
1533 trait_impls: self.trait_impls.clone(),
1535 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1539 pub fn cstore(&self) -> &CStore {
1540 self.crate_loader.cstore()
1543 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1545 MacroKind::Bang => self.dummy_ext_bang.clone(),
1546 MacroKind::Derive => self.dummy_ext_derive.clone(),
1547 MacroKind::Attr => self.non_macro_attr.clone(),
1551 /// Runs the function on each namespace.
1552 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1558 fn is_builtin_macro(&mut self, res: Res) -> bool {
1559 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1562 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1564 match ctxt.outer_expn_data().macro_def_id {
1565 Some(def_id) => return def_id,
1566 None => ctxt.remove_mark(),
1571 /// Entry point to crate resolution.
1572 pub fn resolve_crate(&mut self, krate: &Crate) {
1573 self.session.time("resolve_crate", || {
1574 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1575 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1576 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1577 self.session.time("resolve_main", || self.resolve_main());
1578 self.session.time("resolve_check_unused", || self.check_unused(krate));
1579 self.session.time("resolve_report_errors", || self.report_errors(krate));
1580 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1584 pub fn traits_in_scope(
1586 current_trait: Option<Module<'a>>,
1587 parent_scope: &ParentScope<'a>,
1588 ctxt: SyntaxContext,
1589 assoc_item: Option<(Symbol, Namespace)>,
1590 ) -> Vec<TraitCandidate> {
1591 let mut found_traits = Vec::new();
1593 if let Some(module) = current_trait {
1594 if self.trait_may_have_item(Some(module), assoc_item) {
1595 let def_id = module.def_id();
1596 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1600 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1602 Scope::Module(module, _) => {
1603 this.traits_in_module(module, assoc_item, &mut found_traits);
1605 Scope::StdLibPrelude => {
1606 if let Some(module) = this.prelude {
1607 this.traits_in_module(module, assoc_item, &mut found_traits);
1610 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1611 _ => unreachable!(),
1619 fn traits_in_module(
1622 assoc_item: Option<(Symbol, Namespace)>,
1623 found_traits: &mut Vec<TraitCandidate>,
1625 module.ensure_traits(self);
1626 let traits = module.traits.borrow();
1627 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1628 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1629 let def_id = trait_binding.res().def_id();
1630 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1631 found_traits.push(TraitCandidate { def_id, import_ids });
1636 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1637 // associated item with the given name and namespace (if specified). This is a conservative
1638 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1639 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1640 // associated items.
1641 fn trait_may_have_item(
1643 trait_module: Option<Module<'a>>,
1644 assoc_item: Option<(Symbol, Namespace)>,
1646 match (trait_module, assoc_item) {
1647 (Some(trait_module), Some((name, ns))) => {
1648 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1649 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1650 assoc_ns == ns && assoc_ident.name == name
1657 fn find_transitive_imports(
1659 mut kind: &NameBindingKind<'_>,
1661 ) -> SmallVec<[LocalDefId; 1]> {
1662 let mut import_ids = smallvec![];
1663 while let NameBindingKind::Import { import, binding, .. } = kind {
1664 let id = self.local_def_id(import.id);
1665 self.maybe_unused_trait_imports.insert(id);
1666 self.add_to_glob_map(&import, trait_name);
1667 import_ids.push(id);
1668 kind = &binding.kind;
1673 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1674 let ident = ident.normalize_to_macros_2_0();
1675 let disambiguator = if ident.name == kw::Underscore {
1676 self.underscore_disambiguator += 1;
1677 self.underscore_disambiguator
1681 BindingKey { ident, ns, disambiguator }
1684 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1685 if module.populate_on_access.get() {
1686 module.populate_on_access.set(false);
1687 self.build_reduced_graph_external(module);
1689 &module.lazy_resolutions
1696 ) -> &'a RefCell<NameResolution<'a>> {
1698 .resolutions(module)
1701 .or_insert_with(|| self.arenas.alloc_name_resolution())
1707 used_binding: &'a NameBinding<'a>,
1708 is_lexical_scope: bool,
1710 if let Some((b2, kind)) = used_binding.ambiguity {
1711 self.ambiguity_errors.push(AmbiguityError {
1716 misc1: AmbiguityErrorMisc::None,
1717 misc2: AmbiguityErrorMisc::None,
1720 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1721 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1722 // but not introduce it, as used if they are accessed from lexical scope.
1723 if is_lexical_scope {
1724 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1725 if let Some(crate_item) = entry.extern_crate_item {
1726 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1733 import.used.set(true);
1734 self.used_imports.insert(import.id);
1735 self.add_to_glob_map(&import, ident);
1736 self.record_use(ident, binding, false);
1741 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1742 if import.is_glob() {
1743 let def_id = self.local_def_id(import.id);
1744 self.glob_map.entry(def_id).or_default().insert(ident.name);
1748 /// A generic scope visitor.
1749 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1750 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1753 scope_set: ScopeSet<'a>,
1754 parent_scope: &ParentScope<'a>,
1755 ctxt: SyntaxContext,
1756 mut visitor: impl FnMut(
1759 /*use_prelude*/ bool,
1763 // General principles:
1764 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1765 // built into the language or standard library. This way we can add new names into the
1766 // language or standard library without breaking user code.
1767 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1768 // Places to search (in order of decreasing priority):
1770 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1771 // (open set, not controlled).
1772 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1773 // (open, not controlled).
1774 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1775 // 4. Tool modules (closed, controlled right now, but not in the future).
1776 // 5. Standard library prelude (de-facto closed, controlled).
1777 // 6. Language prelude (closed, controlled).
1779 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1780 // (open set, not controlled).
1781 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1782 // (open, not controlled).
1783 // 3. Standard library prelude (de-facto closed, controlled).
1785 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1786 // are currently reported as errors. They should be higher in priority than preludes
1787 // and probably even names in modules according to the "general principles" above. They
1788 // also should be subject to restricted shadowing because are effectively produced by
1789 // derives (you need to resolve the derive first to add helpers into scope), but they
1790 // should be available before the derive is expanded for compatibility.
1791 // It's mess in general, so we are being conservative for now.
1792 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1793 // priority than prelude macros, but create ambiguities with macros in modules.
1794 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1795 // (open, not controlled). Have higher priority than prelude macros, but create
1796 // ambiguities with `macro_rules`.
1797 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1798 // 4a. User-defined prelude from macro-use
1799 // (open, the open part is from macro expansions, not controlled).
1800 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1801 // 4c. Standard library prelude (de-facto closed, controlled).
1802 // 6. Language prelude: builtin attributes (closed, controlled).
1804 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1805 let (ns, macro_kind, is_absolute_path) = match scope_set {
1806 ScopeSet::All(ns, _) => (ns, None, false),
1807 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1808 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1809 ScopeSet::Late(ns, ..) => (ns, None, false),
1811 let module = match scope_set {
1812 // Start with the specified module.
1813 ScopeSet::Late(_, module, _) => module,
1814 // Jump out of trait or enum modules, they do not act as scopes.
1815 _ => parent_scope.module.nearest_item_scope(),
1817 let mut scope = match ns {
1818 _ if is_absolute_path => Scope::CrateRoot,
1819 TypeNS | ValueNS => Scope::Module(module, None),
1820 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1822 let mut ctxt = ctxt.normalize_to_macros_2_0();
1823 let mut use_prelude = !module.no_implicit_prelude;
1826 let visit = match scope {
1827 // Derive helpers are not in scope when resolving derives in the same container.
1828 Scope::DeriveHelpers(expn_id) => {
1829 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1831 Scope::DeriveHelpersCompat => true,
1832 Scope::MacroRules(macro_rules_scope) => {
1833 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1834 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1835 // As another consequence of this optimization visitors never observe invocation
1836 // scopes for macros that were already expanded.
1837 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1838 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1839 macro_rules_scope.set(next_scope.get());
1846 Scope::CrateRoot => true,
1847 Scope::Module(..) => true,
1848 Scope::RegisteredAttrs => use_prelude,
1849 Scope::MacroUsePrelude => use_prelude || rust_2015,
1850 Scope::BuiltinAttrs => true,
1851 Scope::ExternPrelude => use_prelude || is_absolute_path,
1852 Scope::ToolPrelude => use_prelude,
1853 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1854 Scope::BuiltinTypes => true,
1858 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1859 return break_result;
1863 scope = match scope {
1864 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1865 Scope::DeriveHelpers(expn_id) => {
1866 // Derive helpers are not visible to code generated by bang or derive macros.
1867 let expn_data = expn_id.expn_data();
1868 match expn_data.kind {
1870 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1871 Scope::DeriveHelpersCompat
1873 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1876 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1877 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1878 MacroRulesScope::Binding(binding) => {
1879 Scope::MacroRules(binding.parent_macro_rules_scope)
1881 MacroRulesScope::Invocation(invoc_id) => {
1882 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1884 MacroRulesScope::Empty => Scope::Module(module, None),
1886 Scope::CrateRoot => match ns {
1888 ctxt.adjust(ExpnId::root());
1889 Scope::ExternPrelude
1891 ValueNS | MacroNS => break,
1893 Scope::Module(module, prev_lint_id) => {
1894 use_prelude = !module.no_implicit_prelude;
1895 let derive_fallback_lint_id = match scope_set {
1896 ScopeSet::Late(.., lint_id) => lint_id,
1899 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1900 Some((parent_module, lint_id)) => {
1901 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1904 ctxt.adjust(ExpnId::root());
1906 TypeNS => Scope::ExternPrelude,
1907 ValueNS => Scope::StdLibPrelude,
1908 MacroNS => Scope::RegisteredAttrs,
1913 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1914 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1915 Scope::BuiltinAttrs => break, // nowhere else to search
1916 Scope::ExternPrelude if is_absolute_path => break,
1917 Scope::ExternPrelude => Scope::ToolPrelude,
1918 Scope::ToolPrelude => Scope::StdLibPrelude,
1919 Scope::StdLibPrelude => match ns {
1920 TypeNS => Scope::BuiltinTypes,
1921 ValueNS => break, // nowhere else to search
1922 MacroNS => Scope::BuiltinAttrs,
1924 Scope::BuiltinTypes => break, // nowhere else to search
1931 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1932 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1933 /// `ident` in the first scope that defines it (or None if no scopes define it).
1935 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1936 /// the items are defined in the block. For example,
1939 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1942 /// g(); // This resolves to the local variable `g` since it shadows the item.
1946 /// Invariant: This must only be called during main resolution, not during
1947 /// import resolution.
1948 fn resolve_ident_in_lexical_scope(
1952 parent_scope: &ParentScope<'a>,
1953 record_used_id: Option<NodeId>,
1956 ) -> Option<LexicalScopeBinding<'a>> {
1957 assert!(ns == TypeNS || ns == ValueNS);
1958 let orig_ident = ident;
1959 if ident.name == kw::Empty {
1960 return Some(LexicalScopeBinding::Res(Res::Err));
1962 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1963 // FIXME(jseyfried) improve `Self` hygiene
1964 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1965 (empty_span, empty_span)
1966 } else if ns == TypeNS {
1967 let normalized_span = ident.span.normalize_to_macros_2_0();
1968 (normalized_span, normalized_span)
1970 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1972 ident.span = general_span;
1973 let normalized_ident = Ident { span: normalized_span, ..ident };
1975 // Walk backwards up the ribs in scope.
1976 let record_used = record_used_id.is_some();
1977 let mut module = self.graph_root;
1978 for i in (0..ribs.len()).rev() {
1979 debug!("walk rib\n{:?}", ribs[i].bindings);
1980 // Use the rib kind to determine whether we are resolving parameters
1981 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1982 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1983 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1985 // The ident resolves to a type parameter or local variable.
1986 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1992 *original_rib_ident_def,
1997 module = match ribs[i].kind {
1998 ModuleRibKind(module) => module,
1999 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
2000 // If an invocation of this macro created `ident`, give up on `ident`
2001 // and switch to `ident`'s source from the macro definition.
2002 ident.span.remove_mark();
2009 ModuleKind::Block(..) => {} // We can see through blocks
2013 let item = self.resolve_ident_in_module_unadjusted(
2014 ModuleOrUniformRoot::Module(module),
2021 if let Ok(binding) = item {
2022 // The ident resolves to an item.
2023 return Some(LexicalScopeBinding::Item(binding));
2026 self.early_resolve_ident_in_lexical_scope(
2028 ScopeSet::Late(ns, module, record_used_id),
2035 .map(LexicalScopeBinding::Item)
2038 fn hygienic_lexical_parent(
2041 ctxt: &mut SyntaxContext,
2042 derive_fallback_lint_id: Option<NodeId>,
2043 ) -> Option<(Module<'a>, Option<NodeId>)> {
2044 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2045 return Some((self.expn_def_scope(ctxt.remove_mark()), None));
2048 if let ModuleKind::Block(..) = module.kind {
2049 return Some((module.parent.unwrap().nearest_item_scope(), None));
2052 // We need to support the next case under a deprecation warning
2055 // ---- begin: this comes from a proc macro derive
2056 // mod implementation_details {
2057 // // Note that `MyStruct` is not in scope here.
2058 // impl SomeTrait for MyStruct { ... }
2062 // So we have to fall back to the module's parent during lexical resolution in this case.
2063 if derive_fallback_lint_id.is_some() {
2064 if let Some(parent) = module.parent {
2065 // Inner module is inside the macro, parent module is outside of the macro.
2066 if module.expansion != parent.expansion
2067 && module.expansion.is_descendant_of(parent.expansion)
2069 // The macro is a proc macro derive
2070 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2071 let ext = self.get_macro_by_def_id(def_id);
2072 if ext.builtin_name.is_none()
2073 && ext.macro_kind() == MacroKind::Derive
2074 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2076 return Some((parent, derive_fallback_lint_id));
2086 fn resolve_ident_in_module(
2088 module: ModuleOrUniformRoot<'a>,
2091 parent_scope: &ParentScope<'a>,
2094 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2095 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2096 .map_err(|(determinacy, _)| determinacy)
2099 fn resolve_ident_in_module_ext(
2101 module: ModuleOrUniformRoot<'a>,
2104 parent_scope: &ParentScope<'a>,
2107 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2108 let tmp_parent_scope;
2109 let mut adjusted_parent_scope = parent_scope;
2111 ModuleOrUniformRoot::Module(m) => {
2112 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2114 ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
2115 adjusted_parent_scope = &tmp_parent_scope;
2118 ModuleOrUniformRoot::ExternPrelude => {
2119 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2121 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2125 self.resolve_ident_in_module_unadjusted_ext(
2129 adjusted_parent_scope,
2136 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2137 debug!("resolve_crate_root({:?})", ident);
2138 let mut ctxt = ident.span.ctxt();
2139 let mark = if ident.name == kw::DollarCrate {
2140 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2141 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2142 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2143 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2144 // definitions actually produced by `macro` and `macro` definitions produced by
2145 // `macro_rules!`, but at least such configurations are not stable yet.
2146 ctxt = ctxt.normalize_to_macro_rules();
2148 "resolve_crate_root: marks={:?}",
2149 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2151 let mut iter = ctxt.marks().into_iter().rev().peekable();
2152 let mut result = None;
2153 // Find the last opaque mark from the end if it exists.
2154 while let Some(&(mark, transparency)) = iter.peek() {
2155 if transparency == Transparency::Opaque {
2156 result = Some(mark);
2163 "resolve_crate_root: found opaque mark {:?} {:?}",
2165 result.map(|r| r.expn_data())
2167 // Then find the last semi-transparent mark from the end if it exists.
2168 for (mark, transparency) in iter {
2169 if transparency == Transparency::SemiTransparent {
2170 result = Some(mark);
2176 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2178 result.map(|r| r.expn_data())
2182 debug!("resolve_crate_root: not DollarCrate");
2183 ctxt = ctxt.normalize_to_macros_2_0();
2184 ctxt.adjust(ExpnId::root())
2186 let module = match mark {
2187 Some(def) => self.expn_def_scope(def),
2190 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2193 return self.graph_root;
2196 let module = self.expect_module(
2197 module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(),
2200 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2209 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2210 let mut module = self.expect_module(module.nearest_parent_mod());
2211 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2212 let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark()));
2213 module = self.expect_module(parent.nearest_parent_mod());
2221 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2222 parent_scope: &ParentScope<'a>,
2225 crate_lint: CrateLint,
2226 ) -> PathResult<'a> {
2227 self.resolve_path_with_ribs(
2238 fn resolve_path_with_ribs(
2241 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2242 parent_scope: &ParentScope<'a>,
2245 crate_lint: CrateLint,
2246 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2247 ) -> PathResult<'a> {
2248 let mut module = None;
2249 let mut allow_super = true;
2250 let mut second_binding = None;
2253 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2254 path_span={:?}, crate_lint={:?})",
2255 path, opt_ns, record_used, path_span, crate_lint,
2258 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2259 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2260 let record_segment_res = |this: &mut Self, res| {
2262 if let Some(id) = id {
2263 if !this.partial_res_map.contains_key(&id) {
2264 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2265 this.record_partial_res(id, PartialRes::new(res));
2271 let is_last = i == path.len() - 1;
2272 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2273 let name = ident.name;
2275 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2278 if allow_super && name == kw::Super {
2279 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2280 let self_module = match i {
2281 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2283 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2287 if let Some(self_module) = self_module {
2288 if let Some(parent) = self_module.parent {
2289 module = Some(ModuleOrUniformRoot::Module(
2290 self.resolve_self(&mut ctxt, parent),
2295 let msg = "there are too many leading `super` keywords".to_string();
2296 return PathResult::Failed {
2300 is_error_from_last_segment: false,
2304 if name == kw::SelfLower {
2305 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2306 module = Some(ModuleOrUniformRoot::Module(
2307 self.resolve_self(&mut ctxt, parent_scope.module),
2311 if name == kw::PathRoot && ident.span.rust_2018() {
2312 module = Some(ModuleOrUniformRoot::ExternPrelude);
2315 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2316 // `::a::b` from 2015 macro on 2018 global edition
2317 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2320 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2321 // `::a::b`, `crate::a::b` or `$crate::a::b`
2322 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2328 // Report special messages for path segment keywords in wrong positions.
2329 if ident.is_path_segment_keyword() && i != 0 {
2330 let name_str = if name == kw::PathRoot {
2331 "crate root".to_string()
2333 format!("`{}`", name)
2335 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2336 format!("global paths cannot start with {}", name_str)
2338 format!("{} in paths can only be used in start position", name_str)
2340 return PathResult::Failed {
2344 is_error_from_last_segment: false,
2348 enum FindBindingResult<'a> {
2349 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2350 PathResult(PathResult<'a>),
2352 let find_binding_in_ns = |this: &mut Self, ns| {
2353 let binding = if let Some(module) = module {
2354 this.resolve_ident_in_module(
2362 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2363 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2364 this.early_resolve_ident_in_lexical_scope(
2373 let record_used_id = if record_used {
2374 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2378 match this.resolve_ident_in_lexical_scope(
2386 // we found a locally-imported or available item/module
2387 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2388 // we found a local variable or type param
2389 Some(LexicalScopeBinding::Res(res))
2390 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2392 record_segment_res(this, res);
2393 return FindBindingResult::PathResult(PathResult::NonModule(
2394 PartialRes::with_unresolved_segments(res, path.len() - 1),
2397 _ => Err(Determinacy::determined(record_used)),
2400 FindBindingResult::Binding(binding)
2402 let binding = match find_binding_in_ns(self, ns) {
2403 FindBindingResult::PathResult(x) => return x,
2404 FindBindingResult::Binding(binding) => binding,
2409 second_binding = Some(binding);
2411 let res = binding.res();
2412 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2413 if let Some(next_module) = binding.module() {
2414 module = Some(ModuleOrUniformRoot::Module(next_module));
2415 record_segment_res(self, res);
2416 } else if res == Res::ToolMod && i + 1 != path.len() {
2417 if binding.is_import() {
2421 "cannot use a tool module through an import",
2423 .span_note(binding.span, "the tool module imported here")
2426 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2427 return PathResult::NonModule(PartialRes::new(res));
2428 } else if res == Res::Err {
2429 return PathResult::NonModule(PartialRes::new(Res::Err));
2430 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2431 self.lint_if_path_starts_with_module(
2437 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2442 let label = format!(
2443 "`{}` is {} {}, not a module",
2449 return PathResult::Failed {
2453 is_error_from_last_segment: is_last,
2457 Err(Undetermined) => return PathResult::Indeterminate,
2458 Err(Determined) => {
2459 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2460 if opt_ns.is_some() && !module.is_normal() {
2461 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2462 module.res().unwrap(),
2467 let module_res = match module {
2468 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2471 let (label, suggestion) = if module_res == self.graph_root.res() {
2472 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2473 // Don't look up import candidates if this is a speculative resolve
2474 let mut candidates = if record_used {
2475 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2479 candidates.sort_by_cached_key(|c| {
2480 (c.path.segments.len(), pprust::path_to_string(&c.path))
2482 if let Some(candidate) = candidates.get(0) {
2484 String::from("unresolved import"),
2486 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2487 String::from("a similar path exists"),
2488 Applicability::MaybeIncorrect,
2491 } else if self.session.edition() == Edition::Edition2015 {
2492 (format!("maybe a missing crate `{}`?", ident), None)
2494 (format!("could not find `{}` in the crate root", ident), None)
2502 .map_or(false, |c| c.is_ascii_uppercase())
2504 // Check whether the name refers to an item in the value namespace.
2505 let suggestion = if ribs.is_some() {
2506 let match_span = match self.resolve_ident_in_lexical_scope(
2512 &ribs.unwrap()[ValueNS],
2514 // Name matches a local variable. For example:
2517 // let Foo: &str = "";
2518 // println!("{}", Foo::Bar); // Name refers to local
2519 // // variable `Foo`.
2522 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2523 Some(*self.pat_span_map.get(&id).unwrap())
2526 // Name matches item from a local name binding
2527 // created by `use` declaration. For example:
2529 // pub Foo: &str = "";
2533 // println!("{}", Foo::Bar); // Name refers to local
2534 // // binding `Foo`.
2537 Some(LexicalScopeBinding::Item(name_binding)) => {
2538 Some(name_binding.span)
2543 if let Some(span) = match_span {
2545 vec![(span, String::from(""))],
2546 format!("`{}` is defined here, but is not a type", ident),
2547 Applicability::MaybeIncorrect,
2556 (format!("use of undeclared type `{}`", ident), suggestion)
2558 (format!("use of undeclared crate or module `{}`", ident), None)
2561 let parent = path[i - 1].ident.name;
2562 let parent = match parent {
2563 // ::foo is mounted at the crate root for 2015, and is the extern
2564 // prelude for 2018+
2565 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2566 "the list of imported crates".to_owned()
2568 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2570 format!("`{}`", parent)
2574 let mut msg = format!("could not find `{}` in {}", ident, parent);
2575 if ns == TypeNS || ns == ValueNS {
2576 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2577 if let FindBindingResult::Binding(Ok(binding)) =
2578 find_binding_in_ns(self, ns_to_try)
2580 let mut found = |what| {
2582 "expected {}, found {} `{}` in {}",
2589 if binding.module().is_some() {
2592 match binding.res() {
2593 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2594 _ => found(ns_to_try.descr()),
2601 return PathResult::Failed {
2605 is_error_from_last_segment: is_last,
2611 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2613 PathResult::Module(match module {
2614 Some(module) => module,
2615 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2616 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2620 fn lint_if_path_starts_with_module(
2622 crate_lint: CrateLint,
2625 second_binding: Option<&NameBinding<'_>>,
2627 let (diag_id, diag_span) = match crate_lint {
2628 CrateLint::No => return,
2629 CrateLint::SimplePath(id) => (id, path_span),
2630 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2631 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2634 let first_name = match path.get(0) {
2635 // In the 2018 edition this lint is a hard error, so nothing to do
2636 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2640 // We're only interested in `use` paths which should start with
2641 // `{{root}}` currently.
2642 if first_name != kw::PathRoot {
2647 // If this import looks like `crate::...` it's already good
2648 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2649 // Otherwise go below to see if it's an extern crate
2651 // If the path has length one (and it's `PathRoot` most likely)
2652 // then we don't know whether we're gonna be importing a crate or an
2653 // item in our crate. Defer this lint to elsewhere
2657 // If the first element of our path was actually resolved to an
2658 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2659 // warning, this looks all good!
2660 if let Some(binding) = second_binding {
2661 if let NameBindingKind::Import { import, .. } = binding.kind {
2662 // Careful: we still want to rewrite paths from renamed extern crates.
2663 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2669 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2670 self.lint_buffer.buffer_lint_with_diagnostic(
2671 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2674 "absolute paths must start with `self`, `super`, \
2675 `crate`, or an external crate name in the 2018 edition",
2680 // Validate a local resolution (from ribs).
2681 fn validate_res_from_ribs(
2688 original_rib_ident_def: Ident,
2689 all_ribs: &[Rib<'a>],
2691 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2692 debug!("validate_res_from_ribs({:?})", res);
2693 let ribs = &all_ribs[rib_index + 1..];
2695 // An invalid forward use of a generic parameter from a previous default.
2696 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2698 let res_error = if rib_ident.name == kw::SelfUpper {
2699 ResolutionError::SelfInGenericParamDefault
2701 ResolutionError::ForwardDeclaredGenericParam
2703 self.report_error(span, res_error);
2705 assert_eq!(res, Res::Err);
2711 use ResolutionError::*;
2712 let mut res_err = None;
2717 | ClosureOrAsyncRibKind
2719 | MacroDefinition(..)
2720 | ForwardGenericParamBanRibKind => {
2721 // Nothing to do. Continue.
2723 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2724 // This was an attempt to access an upvar inside a
2725 // named function item. This is not allowed, so we
2728 // We don't immediately trigger a resolve error, because
2729 // we want certain other resolution errors (namely those
2730 // emitted for `ConstantItemRibKind` below) to take
2732 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2735 ConstantItemRibKind(_, item) => {
2736 // Still doesn't deal with upvars
2738 let (span, resolution_error) =
2739 if let Some((ident, constant_item_kind)) = item {
2740 let kind_str = match constant_item_kind {
2741 ConstantItemKind::Const => "const",
2742 ConstantItemKind::Static => "static",
2746 AttemptToUseNonConstantValueInConstant(
2747 ident, "let", kind_str,
2753 AttemptToUseNonConstantValueInConstant(
2754 original_rib_ident_def,
2760 self.report_error(span, resolution_error);
2764 ConstParamTyRibKind => {
2766 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2772 if let Some(res_err) = res_err {
2773 self.report_error(span, res_err);
2777 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2779 let has_generic_params: HasGenericParams = match rib.kind {
2781 | ClosureOrAsyncRibKind
2784 | MacroDefinition(..)
2785 | ForwardGenericParamBanRibKind => {
2786 // Nothing to do. Continue.
2790 ConstantItemRibKind(trivial, _) => {
2791 let features = self.session.features_untracked();
2792 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2793 if !(trivial || features.generic_const_exprs) {
2794 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2795 // we can't easily tell if it's generic at this stage, so we instead remember
2796 // this and then enforce the self type to be concrete later on.
2797 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2798 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2803 ResolutionError::ParamInNonTrivialAnonConst {
2804 name: rib_ident.name,
2810 self.session.delay_span_bug(span, CG_BUG_STR);
2818 // This was an attempt to use a type parameter outside its scope.
2819 ItemRibKind(has_generic_params) => has_generic_params,
2820 FnItemRibKind => HasGenericParams::Yes,
2821 ConstParamTyRibKind => {
2825 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2835 ResolutionError::GenericParamsFromOuterFunction(
2844 Res::Def(DefKind::ConstParam, _) => {
2845 let mut ribs = ribs.iter().peekable();
2846 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2847 // When declaring const parameters inside function signatures, the first rib
2848 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2849 // (spuriously) conflicting with the const param.
2854 let has_generic_params = match rib.kind {
2856 | ClosureOrAsyncRibKind
2859 | MacroDefinition(..)
2860 | ForwardGenericParamBanRibKind => continue,
2862 ConstantItemRibKind(trivial, _) => {
2863 let features = self.session.features_untracked();
2864 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2865 if !(trivial || features.generic_const_exprs) {
2869 ResolutionError::ParamInNonTrivialAnonConst {
2870 name: rib_ident.name,
2876 self.session.delay_span_bug(span, CG_BUG_STR);
2883 ItemRibKind(has_generic_params) => has_generic_params,
2884 FnItemRibKind => HasGenericParams::Yes,
2885 ConstParamTyRibKind => {
2889 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2896 // This was an attempt to use a const parameter outside its scope.
2900 ResolutionError::GenericParamsFromOuterFunction(
2914 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2915 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2916 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2917 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2921 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2922 debug!("(recording pat) recording {:?} for {:?}", node, span);
2923 self.pat_span_map.insert(node, span);
2926 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2927 vis.is_accessible_from(module.nearest_parent_mod(), self)
2930 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2931 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2932 if !ptr::eq(module, old_module) {
2933 span_bug!(binding.span, "parent module is reset for binding");
2938 fn disambiguate_macro_rules_vs_modularized(
2940 macro_rules: &'a NameBinding<'a>,
2941 modularized: &'a NameBinding<'a>,
2943 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2944 // is disambiguated to mitigate regressions from macro modularization.
2945 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2947 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2948 self.binding_parent_modules.get(&PtrKey(modularized)),
2950 (Some(macro_rules), Some(modularized)) => {
2951 macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
2952 && modularized.is_ancestor_of(macro_rules)
2958 fn report_errors(&mut self, krate: &Crate) {
2959 self.report_with_use_injections(krate);
2961 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2962 let msg = "macro-expanded `macro_export` macros from the current crate \
2963 cannot be referred to by absolute paths";
2964 self.lint_buffer.buffer_lint_with_diagnostic(
2965 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2969 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2973 for ambiguity_error in &self.ambiguity_errors {
2974 self.report_ambiguity_error(ambiguity_error);
2977 let mut reported_spans = FxHashSet::default();
2978 for error in &self.privacy_errors {
2979 if reported_spans.insert(error.dedup_span) {
2980 self.report_privacy_error(error);
2985 fn report_with_use_injections(&mut self, krate: &Crate) {
2986 for UseError { mut err, candidates, def_id, instead, suggestion } in
2987 self.use_injections.drain(..)
2989 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2990 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2994 if !candidates.is_empty() {
2995 diagnostics::show_candidates(
3004 } else if let Some((span, msg, sugg, appl)) = suggestion {
3005 err.span_suggestion(span, msg, sugg, appl);
3011 fn report_conflict<'b>(
3016 new_binding: &NameBinding<'b>,
3017 old_binding: &NameBinding<'b>,
3019 // Error on the second of two conflicting names
3020 if old_binding.span.lo() > new_binding.span.lo() {
3021 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
3024 let container = match parent.kind {
3025 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id()),
3026 ModuleKind::Block(..) => "block",
3029 let old_noun = match old_binding.is_import() {
3031 false => "definition",
3034 let new_participle = match new_binding.is_import() {
3040 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3042 if let Some(s) = self.name_already_seen.get(&name) {
3048 let old_kind = match (ns, old_binding.module()) {
3049 (ValueNS, _) => "value",
3050 (MacroNS, _) => "macro",
3051 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3052 (TypeNS, Some(module)) if module.is_normal() => "module",
3053 (TypeNS, Some(module)) if module.is_trait() => "trait",
3054 (TypeNS, _) => "type",
3057 let msg = format!("the name `{}` is defined multiple times", name);
3059 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3060 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3061 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3062 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3063 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3065 _ => match (old_binding.is_import(), new_binding.is_import()) {
3066 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3067 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3068 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3073 "`{}` must be defined only once in the {} namespace of this {}",
3079 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3081 self.session.source_map().guess_head_span(old_binding.span),
3082 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3085 // See https://github.com/rust-lang/rust/issues/32354
3086 use NameBindingKind::Import;
3087 let import = match (&new_binding.kind, &old_binding.kind) {
3088 // If there are two imports where one or both have attributes then prefer removing the
3089 // import without attributes.
3090 (Import { import: new, .. }, Import { import: old, .. })
3092 !new_binding.span.is_dummy()
3093 && !old_binding.span.is_dummy()
3094 && (new.has_attributes || old.has_attributes)
3097 if old.has_attributes {
3098 Some((new, new_binding.span, true))
3100 Some((old, old_binding.span, true))
3103 // Otherwise prioritize the new binding.
3104 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3105 Some((import, new_binding.span, other.is_import()))
3107 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3108 Some((import, old_binding.span, other.is_import()))
3113 // Check if the target of the use for both bindings is the same.
3114 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3115 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3117 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3118 // Only suggest removing an import if both bindings are to the same def, if both spans
3119 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3120 // been introduced by an item.
3121 let should_remove_import = duplicate
3123 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3126 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3127 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3129 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3130 // Simple case - remove the entire import. Due to the above match arm, this can
3131 // only be a single use so just remove it entirely.
3132 err.tool_only_span_suggestion(
3133 import.use_span_with_attributes,
3134 "remove unnecessary import",
3136 Applicability::MaybeIncorrect,
3139 Some((import, span, _)) => {
3140 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3146 self.name_already_seen.insert(name, span);
3149 /// This function adds a suggestion to change the binding name of a new import that conflicts
3150 /// with an existing import.
3152 /// ```text,ignore (diagnostic)
3153 /// help: you can use `as` to change the binding name of the import
3155 /// LL | use foo::bar as other_bar;
3156 /// | ^^^^^^^^^^^^^^^^^^^^^
3158 fn add_suggestion_for_rename_of_use(
3160 err: &mut DiagnosticBuilder<'_>,
3162 import: &Import<'_>,
3165 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3166 format!("Other{}", name)
3168 format!("other_{}", name)
3171 let mut suggestion = None;
3173 ImportKind::Single { type_ns_only: true, .. } => {
3174 suggestion = Some(format!("self as {}", suggested_name))
3176 ImportKind::Single { source, .. } => {
3178 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3180 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3181 if pos <= snippet.len() {
3182 suggestion = Some(format!(
3186 if snippet.ends_with(';') { ";" } else { "" }
3192 ImportKind::ExternCrate { source, target, .. } => {
3193 suggestion = Some(format!(
3194 "extern crate {} as {};",
3195 source.unwrap_or(target.name),
3199 _ => unreachable!(),
3202 let rename_msg = "you can use `as` to change the binding name of the import";
3203 if let Some(suggestion) = suggestion {
3204 err.span_suggestion(
3208 Applicability::MaybeIncorrect,
3211 err.span_label(binding_span, rename_msg);
3215 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3216 /// nested. In the following example, this function will be invoked to remove the `a` binding
3217 /// in the second use statement:
3219 /// ```ignore (diagnostic)
3220 /// use issue_52891::a;
3221 /// use issue_52891::{d, a, e};
3224 /// The following suggestion will be added:
3226 /// ```ignore (diagnostic)
3227 /// use issue_52891::{d, a, e};
3228 /// ^-- help: remove unnecessary import
3231 /// If the nested use contains only one import then the suggestion will remove the entire
3234 /// It is expected that the provided import is nested - this isn't checked by the
3235 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3236 /// as characters expected by span manipulations won't be present.
3237 fn add_suggestion_for_duplicate_nested_use(
3239 err: &mut DiagnosticBuilder<'_>,
3240 import: &Import<'_>,
3243 assert!(import.is_nested());
3244 let message = "remove unnecessary import";
3246 // Two examples will be used to illustrate the span manipulations we're doing:
3248 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3249 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3250 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3251 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3253 let (found_closing_brace, span) =
3254 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3256 // If there was a closing brace then identify the span to remove any trailing commas from
3257 // previous imports.
3258 if found_closing_brace {
3259 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3260 err.tool_only_span_suggestion(
3264 Applicability::MaybeIncorrect,
3267 // Remove the entire line if we cannot extend the span back, this indicates an
3268 // `issue_52891::{self}` case.
3269 err.span_suggestion(
3270 import.use_span_with_attributes,
3273 Applicability::MaybeIncorrect,
3280 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3283 fn extern_prelude_get(
3287 ) -> Option<&'a NameBinding<'a>> {
3288 if ident.is_path_segment_keyword() {
3289 // Make sure `self`, `super` etc produce an error when passed to here.
3292 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3293 if let Some(binding) = entry.extern_crate_item {
3294 if !speculative && entry.introduced_by_item {
3295 self.record_use(ident, binding, false);
3299 let crate_id = if !speculative {
3300 self.crate_loader.process_path_extern(ident.name, ident.span)
3302 self.crate_loader.maybe_process_path_extern(ident.name)?
3304 let crate_root = self.expect_module(crate_id.as_def_id());
3306 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3307 .to_name_binding(self.arenas),
3313 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3314 /// isn't something that can be returned because it can't be made to live that long,
3315 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3316 /// just that an error occurred.
3317 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3318 pub fn resolve_str_path_error(
3324 ) -> Result<(ast::Path, Res), ()> {
3325 let path = if path_str.starts_with("::") {
3328 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3329 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3330 .map(|i| self.new_ast_path_segment(i))
3339 .map(Ident::from_str)
3340 .map(|i| self.new_ast_path_segment(i))
3345 let module = self.expect_module(module_id);
3346 let parent_scope = &ParentScope::module(module, self);
3347 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3351 // Resolve a path passed from rustdoc or HIR lowering.
3352 fn resolve_ast_path(
3356 parent_scope: &ParentScope<'a>,
3357 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3358 match self.resolve_path(
3359 &Segment::from_path(path),
3366 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3367 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3368 Ok(path_res.base_res())
3370 PathResult::NonModule(..) => Err((
3372 ResolutionError::FailedToResolve {
3373 label: String::from("type-relative paths are not supported in this context"),
3377 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3378 PathResult::Failed { span, label, suggestion, .. } => {
3379 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3384 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3385 let mut seg = ast::PathSegment::from_ident(ident);
3386 seg.id = self.next_node_id();
3391 pub fn graph_root(&self) -> Module<'a> {
3396 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3400 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3402 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3403 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3406 /// Checks if an expression refers to a function marked with
3407 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3408 /// from the attribute.
3409 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3410 if let ExprKind::Path(None, path) = &expr.kind {
3411 // Don't perform legacy const generics rewriting if the path already
3412 // has generic arguments.
3413 if path.segments.last().unwrap().args.is_some() {
3417 let partial_res = self.partial_res_map.get(&expr.id)?;
3418 if partial_res.unresolved_segments() != 0 {
3422 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3423 // We only support cross-crate argument rewriting. Uses
3424 // within the same crate should be updated to use the new
3425 // const generics style.
3426 if def_id.is_local() {
3430 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3434 let parse_attrs = || {
3435 let attrs = self.cstore().item_attrs(def_id, self.session);
3437 attrs.iter().find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3438 let mut ret = vec![];
3439 for meta in attr.meta_item_list()? {
3440 match meta.literal()?.kind {
3441 LitKind::Int(a, _) => {
3442 ret.push(a as usize);
3444 _ => panic!("invalid arg index"),
3450 // Cache the lookup to avoid parsing attributes for an iterm
3452 let ret = parse_attrs();
3453 self.legacy_const_generic_args.insert(def_id, ret.clone());
3460 fn resolve_main(&mut self) {
3461 let module = self.graph_root;
3462 let ident = Ident::with_dummy_span(sym::main);
3463 let parent_scope = &ParentScope::module(module, self);
3465 let name_binding = match self.resolve_ident_in_module(
3466 ModuleOrUniformRoot::Module(module),
3473 Ok(name_binding) => name_binding,
3477 let res = name_binding.res();
3478 let is_import = name_binding.is_import();
3479 let span = name_binding.span;
3480 if let Res::Def(DefKind::Fn, _) = res {
3481 self.record_use(ident, name_binding, false);
3483 self.main_def = Some(MainDefinition { res, is_import, span });
3487 fn names_to_string(names: &[Symbol]) -> String {
3488 let mut result = String::new();
3489 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3491 result.push_str("::");
3493 if Ident::with_dummy_span(*name).is_raw_guess() {
3494 result.push_str("r#");
3496 result.push_str(&name.as_str());
3501 fn path_names_to_string(path: &Path) -> String {
3502 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3505 /// A somewhat inefficient routine to obtain the name of a module.
3506 fn module_to_string(module: Module<'_>) -> Option<String> {
3507 let mut names = Vec::new();
3509 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3510 if let ModuleKind::Def(.., name) = module.kind {
3511 if let Some(parent) = module.parent {
3513 collect_mod(names, parent);
3516 names.push(Symbol::intern("<opaque>"));
3517 collect_mod(names, module.parent.unwrap());
3520 collect_mod(&mut names, module);
3522 if names.is_empty() {
3526 Some(names_to_string(&names))
3529 #[derive(Copy, Clone, Debug)]
3531 /// Do not issue the lint.
3534 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3535 /// In this case, we can take the span of that path.
3538 /// This lint comes from a `use` statement. In this case, what we
3539 /// care about really is the *root* `use` statement; e.g., if we
3540 /// have nested things like `use a::{b, c}`, we care about the
3542 UsePath { root_id: NodeId, root_span: Span },
3544 /// This is the "trait item" from a fully qualified path. For example,
3545 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3546 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3547 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3551 fn node_id(&self) -> Option<NodeId> {
3553 CrateLint::No => None,
3554 CrateLint::SimplePath(id)
3555 | CrateLint::UsePath { root_id: id, .. }
3556 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3561 pub fn provide(providers: &mut Providers) {
3562 late::lifetimes::provide(providers);