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 `librustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
12 #![feature(box_patterns)]
13 #![feature(bool_to_option)]
14 #![feature(crate_visibility_modifier)]
15 #![feature(format_args_capture)]
17 #![feature(or_patterns)]
18 #![recursion_limit = "256"]
20 pub use rustc_hir::def::{Namespace, PerNS};
24 use rustc_arena::{DroplessArena, TypedArena};
25 use rustc_ast::node_id::NodeMap;
26 use rustc_ast::unwrap_or;
27 use rustc_ast::visit::{self, Visitor};
28 use rustc_ast::{self as ast, NodeId};
29 use rustc_ast::{Crate, CRATE_NODE_ID};
30 use rustc_ast::{ItemKind, Path};
31 use rustc_ast_lowering::ResolverAstLowering;
32 use rustc_ast_pretty::pprust;
33 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
34 use rustc_data_structures::ptr_key::PtrKey;
35 use rustc_data_structures::sync::Lrc;
36 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
37 use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
38 use rustc_hir::def::Namespace::*;
39 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
40 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
41 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
42 use rustc_hir::{PrimTy, TraitCandidate};
43 use rustc_index::vec::IndexVec;
44 use rustc_metadata::creader::{CStore, CrateLoader};
45 use rustc_middle::hir::exports::ExportMap;
46 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
47 use rustc_middle::span_bug;
48 use rustc_middle::ty::query::Providers;
49 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
50 use rustc_session::lint;
51 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
52 use rustc_session::Session;
53 use rustc_span::edition::Edition;
54 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
55 use rustc_span::source_map::Spanned;
56 use rustc_span::symbol::{kw, sym, Ident, Symbol};
57 use rustc_span::{Span, DUMMY_SP};
59 use smallvec::{smallvec, SmallVec};
60 use std::cell::{Cell, RefCell};
61 use std::collections::BTreeSet;
62 use std::{cmp, fmt, iter, ptr};
65 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
66 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
67 use imports::{Import, ImportKind, ImportResolver, NameResolution};
68 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
69 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
71 type Res = def::Res<NodeId>;
73 mod build_reduced_graph;
86 #[derive(Copy, Clone, PartialEq, Debug)]
87 pub enum Determinacy {
93 fn determined(determined: bool) -> Determinacy {
94 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
98 /// A specific scope in which a name can be looked up.
99 /// This enum is currently used only for early resolution (imports and macros),
100 /// but not for late resolution yet.
101 #[derive(Clone, Copy)]
103 DeriveHelpers(ExpnId),
105 MacroRules(MacroRulesScopeRef<'a>),
117 /// Names from different contexts may want to visit different subsets of all specific scopes
118 /// with different restrictions when looking up the resolution.
119 /// This enum is currently used only for early resolution (imports and macros),
120 /// but not for late resolution yet.
122 /// All scopes with the given namespace.
123 All(Namespace, /*is_import*/ bool),
124 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
125 AbsolutePath(Namespace),
126 /// All scopes with macro namespace and the given macro kind restriction.
130 /// Everything you need to know about a name's location to resolve it.
131 /// Serves as a starting point for the scope visitor.
132 /// This struct is currently used only for early resolution (imports and macros),
133 /// but not for late resolution yet.
134 #[derive(Clone, Copy, Debug)]
135 pub struct ParentScope<'a> {
138 macro_rules: MacroRulesScopeRef<'a>,
139 derives: &'a [ast::Path],
142 impl<'a> ParentScope<'a> {
143 /// Creates a parent scope with the passed argument used as the module scope component,
144 /// and other scope components set to default empty values.
145 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
148 expansion: ExpnId::root(),
149 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
156 struct BindingError {
158 origin: BTreeSet<Span>,
159 target: BTreeSet<Span>,
163 impl PartialOrd for BindingError {
164 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
165 Some(self.cmp(other))
169 impl PartialEq for BindingError {
170 fn eq(&self, other: &BindingError) -> bool {
171 self.name == other.name
175 impl Ord for BindingError {
176 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
177 self.name.cmp(&other.name)
181 enum ResolutionError<'a> {
182 /// Error E0401: can't use type or const parameters from outer function.
183 GenericParamsFromOuterFunction(Res, HasGenericParams),
184 /// Error E0403: the name is already used for a type or const parameter in this generic
186 NameAlreadyUsedInParameterList(Symbol, Span),
187 /// Error E0407: method is not a member of trait.
188 MethodNotMemberOfTrait(Symbol, &'a str),
189 /// Error E0437: type is not a member of trait.
190 TypeNotMemberOfTrait(Symbol, &'a str),
191 /// Error E0438: const is not a member of trait.
192 ConstNotMemberOfTrait(Symbol, &'a str),
193 /// Error E0408: variable `{}` is not bound in all patterns.
194 VariableNotBoundInPattern(&'a BindingError),
195 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
196 VariableBoundWithDifferentMode(Symbol, Span),
197 /// Error E0415: identifier is bound more than once in this parameter list.
198 IdentifierBoundMoreThanOnceInParameterList(Symbol),
199 /// Error E0416: identifier is bound more than once in the same pattern.
200 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
201 /// Error E0426: use of undeclared label.
202 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
203 /// Error E0429: `self` imports are only allowed within a `{ }` list.
204 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
205 /// Error E0430: `self` import can only appear once in the list.
206 SelfImportCanOnlyAppearOnceInTheList,
207 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
208 SelfImportOnlyInImportListWithNonEmptyPrefix,
209 /// Error E0433: failed to resolve.
210 FailedToResolve { label: String, suggestion: Option<Suggestion> },
211 /// Error E0434: can't capture dynamic environment in a fn item.
212 CannotCaptureDynamicEnvironmentInFnItem,
213 /// Error E0435: attempt to use a non-constant value in a constant.
214 AttemptToUseNonConstantValueInConstant(
216 /* suggestion */ &'static str,
217 /* current */ &'static str,
219 /// Error E0530: `X` bindings cannot shadow `Y`s.
220 BindingShadowsSomethingUnacceptable(&'static str, Symbol, &'a NameBinding<'a>),
221 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
222 ForwardDeclaredTyParam, // FIXME(const_generics_defaults)
223 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
224 ParamInTyOfConstParam(Symbol),
225 /// constant values inside of type parameter defaults must not depend on generic parameters.
226 ParamInAnonConstInTyDefault(Symbol),
227 /// generic parameters must not be used inside const evaluations.
229 /// This error is only emitted when using `min_const_generics`.
230 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
231 /// Error E0735: type parameters with a default cannot use `Self`
232 SelfInTyParamDefault,
233 /// Error E0767: use of unreachable label
234 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
237 enum VisResolutionError<'a> {
238 Relative2018(Span, &'a ast::Path),
240 FailedToResolve(Span, String, Option<Suggestion>),
241 ExpectedFound(Span, String, Res),
246 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
247 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
248 #[derive(Clone, Copy, Debug)]
252 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
253 /// nonsensical suggestions.
254 has_generic_args: bool,
258 fn from_path(path: &Path) -> Vec<Segment> {
259 path.segments.iter().map(|s| s.into()).collect()
262 fn from_ident(ident: Ident) -> Segment {
263 Segment { ident, id: None, has_generic_args: false }
266 fn names_to_string(segments: &[Segment]) -> String {
267 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
271 impl<'a> From<&'a ast::PathSegment> for Segment {
272 fn from(seg: &'a ast::PathSegment) -> Segment {
273 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
277 struct UsePlacementFinder {
278 target_module: NodeId,
283 impl UsePlacementFinder {
284 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
285 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
286 visit::walk_crate(&mut finder, krate);
287 (finder.span, finder.found_use)
291 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
294 module: &'tcx ast::Mod,
296 _: &[ast::Attribute],
299 if self.span.is_some() {
302 if node_id != self.target_module {
303 visit::walk_mod(self, module);
306 // find a use statement
307 for item in &module.items {
309 ItemKind::Use(..) => {
310 // don't suggest placing a use before the prelude
311 // import or other generated ones
312 if !item.span.from_expansion() {
313 self.span = Some(item.span.shrink_to_lo());
314 self.found_use = true;
318 // don't place use before extern crate
319 ItemKind::ExternCrate(_) => {}
320 // but place them before the first other item
322 if self.span.map_or(true, |span| item.span < span)
323 && !item.span.from_expansion()
325 // don't insert between attributes and an item
326 if item.attrs.is_empty() {
327 self.span = Some(item.span.shrink_to_lo());
329 // find the first attribute on the item
330 for attr in &item.attrs {
331 if self.span.map_or(true, |span| attr.span < span) {
332 self.span = Some(attr.span.shrink_to_lo());
343 /// An intermediate resolution result.
345 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
346 /// items are visible in their whole block, while `Res`es only from the place they are defined
349 enum LexicalScopeBinding<'a> {
350 Item(&'a NameBinding<'a>),
354 impl<'a> LexicalScopeBinding<'a> {
355 fn res(self) -> Res {
357 LexicalScopeBinding::Item(binding) => binding.res(),
358 LexicalScopeBinding::Res(res) => res,
363 #[derive(Copy, Clone, Debug)]
364 enum ModuleOrUniformRoot<'a> {
368 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
369 CrateRootAndExternPrelude,
371 /// Virtual module that denotes resolution in extern prelude.
372 /// Used for paths starting with `::` on 2018 edition.
375 /// Virtual module that denotes resolution in current scope.
376 /// Used only for resolving single-segment imports. The reason it exists is that import paths
377 /// are always split into two parts, the first of which should be some kind of module.
381 impl ModuleOrUniformRoot<'_> {
382 fn same_def(lhs: Self, rhs: Self) -> bool {
384 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
385 lhs.def_id() == rhs.def_id()
388 ModuleOrUniformRoot::CrateRootAndExternPrelude,
389 ModuleOrUniformRoot::CrateRootAndExternPrelude,
391 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
392 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
398 #[derive(Clone, Debug)]
399 enum PathResult<'a> {
400 Module(ModuleOrUniformRoot<'a>),
401 NonModule(PartialRes),
406 suggestion: Option<Suggestion>,
407 is_error_from_last_segment: bool,
413 /// An anonymous module; e.g., just a block.
418 /// { // This is an anonymous module
419 /// f(); // This resolves to (2) as we are inside the block.
422 /// f(); // Resolves to (1)
426 /// Any module with a name.
430 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
431 /// or the crate root (which is conceptually a top-level module).
432 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
433 /// * A trait or an enum (it implicitly contains associated types, methods and variant
435 Def(DefKind, DefId, Symbol),
439 /// Get name of the module.
440 pub fn name(&self) -> Option<Symbol> {
442 ModuleKind::Block(..) => None,
443 ModuleKind::Def(.., name) => Some(*name),
448 /// A key that identifies a binding in a given `Module`.
450 /// Multiple bindings in the same module can have the same key (in a valid
451 /// program) if all but one of them come from glob imports.
452 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
454 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
458 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
459 /// `_` in the expanded AST that introduced this binding.
463 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
465 /// One node in the tree of modules.
467 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
470 /// * crate root (aka, top-level anonymous module)
473 /// * curly-braced block with statements
475 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
476 pub struct ModuleData<'a> {
477 /// The direct parent module (it may not be a `mod`, however).
478 parent: Option<Module<'a>>,
479 /// What kind of module this is, because this may not be a `mod`.
482 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
483 /// This may be the crate root.
484 nearest_parent_mod: DefId,
486 /// Mapping between names and their (possibly in-progress) resolutions in this module.
487 /// Resolutions in modules from other crates are not populated until accessed.
488 lazy_resolutions: Resolutions<'a>,
489 /// True if this is a module from other crate that needs to be populated on access.
490 populate_on_access: Cell<bool>,
492 /// Macro invocations that can expand into items in this module.
493 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
495 /// Whether `#[no_implicit_prelude]` is active.
496 no_implicit_prelude: bool,
498 glob_importers: RefCell<Vec<&'a Import<'a>>>,
499 globs: RefCell<Vec<&'a Import<'a>>>,
501 /// Used to memoize the traits in this module for faster searches through all traits in scope.
502 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
504 /// Span of the module itself. Used for error reporting.
510 type Module<'a> = &'a ModuleData<'a>;
512 impl<'a> ModuleData<'a> {
514 parent: Option<Module<'a>>,
516 nearest_parent_mod: DefId,
524 lazy_resolutions: Default::default(),
525 populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
526 unexpanded_invocations: Default::default(),
527 no_implicit_prelude: false,
528 glob_importers: RefCell::new(Vec::new()),
529 globs: RefCell::new(Vec::new()),
530 traits: RefCell::new(None),
536 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
538 R: AsMut<Resolver<'a>>,
539 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
541 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
542 if let Some(binding) = name_resolution.borrow().binding {
543 f(resolver, key.ident, key.ns, binding);
548 /// This modifies `self` in place. The traits will be stored in `self.traits`.
549 fn ensure_traits<R>(&'a self, resolver: &mut R)
551 R: AsMut<Resolver<'a>>,
553 let mut traits = self.traits.borrow_mut();
554 if traits.is_none() {
555 let mut collected_traits = Vec::new();
556 self.for_each_child(resolver, |_, name, ns, binding| {
560 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
561 collected_traits.push((name, binding))
564 *traits = Some(collected_traits.into_boxed_slice());
568 fn res(&self) -> Option<Res> {
570 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
575 fn def_id(&self) -> Option<DefId> {
577 ModuleKind::Def(_, def_id, _) => Some(def_id),
582 // `self` resolves to the first module ancestor that `is_normal`.
583 fn is_normal(&self) -> bool {
584 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
587 fn is_trait(&self) -> bool {
588 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
591 fn nearest_item_scope(&'a self) -> Module<'a> {
593 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
594 self.parent.expect("enum or trait module without a parent")
600 fn is_ancestor_of(&self, mut other: &Self) -> bool {
601 while !ptr::eq(self, other) {
602 if let Some(parent) = other.parent {
612 impl<'a> fmt::Debug for ModuleData<'a> {
613 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
614 write!(f, "{:?}", self.res())
618 /// Records a possibly-private value, type, or module definition.
619 #[derive(Clone, Debug)]
620 pub struct NameBinding<'a> {
621 kind: NameBindingKind<'a>,
622 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
628 pub trait ToNameBinding<'a> {
629 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
632 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
633 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
638 #[derive(Clone, Debug)]
639 enum NameBindingKind<'a> {
640 Res(Res, /* is_macro_export */ bool),
642 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
645 impl<'a> NameBindingKind<'a> {
646 /// Is this a name binding of a import?
647 fn is_import(&self) -> bool {
648 matches!(*self, NameBindingKind::Import { .. })
652 struct PrivacyError<'a> {
654 binding: &'a NameBinding<'a>,
658 struct UseError<'a> {
659 err: DiagnosticBuilder<'a>,
660 /// Candidates which user could `use` to access the missing type.
661 candidates: Vec<ImportSuggestion>,
662 /// The `DefId` of the module to place the use-statements in.
664 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
666 /// Extra free-form suggestion.
667 suggestion: Option<(Span, &'static str, String, Applicability)>,
670 #[derive(Clone, Copy, PartialEq, Debug)]
675 MacroRulesVsModularized,
683 fn descr(self) -> &'static str {
685 AmbiguityKind::Import => "name vs any other name during import resolution",
686 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
687 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
688 AmbiguityKind::MacroRulesVsModularized => {
689 "`macro_rules` vs non-`macro_rules` from other module"
691 AmbiguityKind::GlobVsOuter => {
692 "glob import vs any other name from outer scope during import/macro resolution"
694 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
695 AmbiguityKind::GlobVsExpanded => {
696 "glob import vs macro-expanded name in the same \
697 module during import/macro resolution"
699 AmbiguityKind::MoreExpandedVsOuter => {
700 "macro-expanded name vs less macro-expanded name \
701 from outer scope during import/macro resolution"
707 /// Miscellaneous bits of metadata for better ambiguity error reporting.
708 #[derive(Clone, Copy, PartialEq)]
709 enum AmbiguityErrorMisc {
716 struct AmbiguityError<'a> {
719 b1: &'a NameBinding<'a>,
720 b2: &'a NameBinding<'a>,
721 misc1: AmbiguityErrorMisc,
722 misc2: AmbiguityErrorMisc,
725 impl<'a> NameBinding<'a> {
726 fn module(&self) -> Option<Module<'a>> {
728 NameBindingKind::Module(module) => Some(module),
729 NameBindingKind::Import { binding, .. } => binding.module(),
734 fn res(&self) -> Res {
736 NameBindingKind::Res(res, _) => res,
737 NameBindingKind::Module(module) => module.res().unwrap(),
738 NameBindingKind::Import { binding, .. } => binding.res(),
742 fn is_ambiguity(&self) -> bool {
743 self.ambiguity.is_some()
745 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
750 fn is_possibly_imported_variant(&self) -> bool {
752 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
753 NameBindingKind::Res(
754 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
757 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
761 fn is_extern_crate(&self) -> bool {
763 NameBindingKind::Import {
764 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
767 NameBindingKind::Module(&ModuleData {
768 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
770 }) => def_id.index == CRATE_DEF_INDEX,
775 fn is_import(&self) -> bool {
776 matches!(self.kind, NameBindingKind::Import { .. })
779 fn is_glob_import(&self) -> bool {
781 NameBindingKind::Import { import, .. } => import.is_glob(),
786 fn is_importable(&self) -> bool {
789 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
793 fn is_macro_def(&self) -> bool {
794 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
797 fn macro_kind(&self) -> Option<MacroKind> {
798 self.res().macro_kind()
801 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
802 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
803 // Then this function returns `true` if `self` may emerge from a macro *after* that
804 // in some later round and screw up our previously found resolution.
805 // See more detailed explanation in
806 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
807 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
808 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
809 // Expansions are partially ordered, so "may appear after" is an inversion of
810 // "certainly appears before or simultaneously" and includes unordered cases.
811 let self_parent_expansion = self.expansion;
812 let other_parent_expansion = binding.expansion;
813 let certainly_before_other_or_simultaneously =
814 other_parent_expansion.is_descendant_of(self_parent_expansion);
815 let certainly_before_invoc_or_simultaneously =
816 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
817 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
821 #[derive(Debug, Default, Clone)]
822 pub struct ExternPreludeEntry<'a> {
823 extern_crate_item: Option<&'a NameBinding<'a>>,
824 pub introduced_by_item: bool,
827 /// Used for better errors for E0773
828 enum BuiltinMacroState {
829 NotYetSeen(SyntaxExtensionKind),
833 /// The main resolver class.
835 /// This is the visitor that walks the whole crate.
836 pub struct Resolver<'a> {
837 session: &'a Session,
839 definitions: Definitions,
841 graph_root: Module<'a>,
843 prelude: Option<Module<'a>>,
844 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
846 /// N.B., this is used only for better diagnostics, not name resolution itself.
847 has_self: FxHashSet<DefId>,
849 /// Names of fields of an item `DefId` accessible with dot syntax.
850 /// Used for hints during error reporting.
851 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
853 /// All imports known to succeed or fail.
854 determined_imports: Vec<&'a Import<'a>>,
856 /// All non-determined imports.
857 indeterminate_imports: Vec<&'a Import<'a>>,
859 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
860 /// We are resolving a last import segment during import validation.
861 last_import_segment: bool,
862 /// This binding should be ignored during in-module resolution, so that we don't get
863 /// "self-confirming" import resolutions during import validation.
864 unusable_binding: Option<&'a NameBinding<'a>>,
866 /// Resolutions for nodes that have a single resolution.
867 partial_res_map: NodeMap<PartialRes>,
868 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
869 import_res_map: NodeMap<PerNS<Option<Res>>>,
870 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
871 label_res_map: NodeMap<NodeId>,
873 /// `CrateNum` resolutions of `extern crate` items.
874 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
875 export_map: ExportMap<LocalDefId>,
876 trait_map: NodeMap<Vec<TraitCandidate>>,
878 /// A map from nodes to anonymous modules.
879 /// Anonymous modules are pseudo-modules that are implicitly created around items
880 /// contained within blocks.
882 /// For example, if we have this:
890 /// There will be an anonymous module created around `g` with the ID of the
891 /// entry block for `f`.
892 block_map: NodeMap<Module<'a>>,
893 /// A fake module that contains no definition and no prelude. Used so that
894 /// some AST passes can generate identifiers that only resolve to local or
896 empty_module: Module<'a>,
897 module_map: FxHashMap<LocalDefId, Module<'a>>,
898 extern_module_map: FxHashMap<DefId, Module<'a>>,
899 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
900 underscore_disambiguator: u32,
902 /// Maps glob imports to the names of items actually imported.
903 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
904 /// Visibilities in "lowered" form, for all entities that have them.
905 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
906 used_imports: FxHashSet<(NodeId, Namespace)>,
907 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
908 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
910 /// Privacy errors are delayed until the end in order to deduplicate them.
911 privacy_errors: Vec<PrivacyError<'a>>,
912 /// Ambiguity errors are delayed for deduplication.
913 ambiguity_errors: Vec<AmbiguityError<'a>>,
914 /// `use` injections are delayed for better placement and deduplication.
915 use_injections: Vec<UseError<'a>>,
916 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
917 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
919 arenas: &'a ResolverArenas<'a>,
920 dummy_binding: &'a NameBinding<'a>,
922 crate_loader: CrateLoader<'a>,
923 macro_names: FxHashSet<Ident>,
924 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
925 registered_attrs: FxHashSet<Ident>,
926 registered_tools: FxHashSet<Ident>,
927 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
928 all_macros: FxHashMap<Symbol, Res>,
929 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
930 dummy_ext_bang: Lrc<SyntaxExtension>,
931 dummy_ext_derive: Lrc<SyntaxExtension>,
932 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
933 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
934 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
935 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
936 proc_macro_stubs: FxHashSet<LocalDefId>,
937 /// Traces collected during macro resolution and validated when it's complete.
938 single_segment_macro_resolutions:
939 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
940 multi_segment_macro_resolutions:
941 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
942 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
943 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
944 /// Derive macros cannot modify the item themselves and have to store the markers in the global
945 /// context, so they attach the markers to derive container IDs using this resolver table.
946 containers_deriving_copy: FxHashSet<ExpnId>,
947 /// Parent scopes in which the macros were invoked.
948 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
949 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
950 /// `macro_rules` scopes *produced* by expanding the macro invocations,
951 /// include all the `macro_rules` items and other invocations generated by them.
952 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScopeRef<'a>>,
953 /// Helper attributes that are in scope for the given expansion.
954 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
955 /// Resolutions for paths inside the `#[derive(...)]` attribute with the given `ExpnId`.
956 derive_resolutions: FxHashMap<ExpnId, Vec<(Lrc<SyntaxExtension>, ast::Path)>>,
958 /// Avoid duplicated errors for "name already defined".
959 name_already_seen: FxHashMap<Symbol, Span>,
961 potentially_unused_imports: Vec<&'a Import<'a>>,
963 /// Table for mapping struct IDs into struct constructor IDs,
964 /// it's not used during normal resolution, only for better error reporting.
965 /// Also includes of list of each fields visibility
966 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
968 /// Features enabled for this crate.
969 active_features: FxHashSet<Symbol>,
971 lint_buffer: LintBuffer,
973 next_node_id: NodeId,
975 def_id_to_span: IndexVec<LocalDefId, Span>,
977 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
978 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
980 /// Indices of unnamed struct or variant fields with unresolved attributes.
981 placeholder_field_indices: FxHashMap<NodeId, usize>,
982 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
983 /// we know what parent node that fragment should be attached to thanks to this table.
984 invocation_parents: FxHashMap<ExpnId, LocalDefId>,
986 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
987 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
988 /// FIXME: Replace with a more general AST map (together with some other fields).
989 trait_impl_items: FxHashSet<LocalDefId>,
992 /// Nothing really interesting here; it just provides memory for the rest of the crate.
994 pub struct ResolverArenas<'a> {
995 modules: TypedArena<ModuleData<'a>>,
996 local_modules: RefCell<Vec<Module<'a>>>,
997 imports: TypedArena<Import<'a>>,
998 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
999 ast_paths: TypedArena<ast::Path>,
1000 dropless: DroplessArena,
1003 impl<'a> ResolverArenas<'a> {
1004 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1005 let module = self.modules.alloc(module);
1006 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1007 self.local_modules.borrow_mut().push(module);
1011 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1012 self.local_modules.borrow()
1014 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1015 self.dropless.alloc(name_binding)
1017 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1018 self.imports.alloc(import)
1020 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1021 self.name_resolutions.alloc(Default::default())
1023 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1024 PtrKey(self.dropless.alloc(Cell::new(scope)))
1026 fn alloc_macro_rules_binding(
1028 binding: MacroRulesBinding<'a>,
1029 ) -> &'a MacroRulesBinding<'a> {
1030 self.dropless.alloc(binding)
1032 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1033 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1035 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1036 self.dropless.alloc_from_iter(spans)
1040 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1041 fn as_mut(&mut self) -> &mut Resolver<'a> {
1046 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1047 fn parent(self, id: DefId) -> Option<DefId> {
1048 match id.as_local() {
1049 Some(id) => self.definitions.def_key(id).parent,
1050 None => self.cstore().def_key(id).parent,
1052 .map(|index| DefId { index, ..id })
1056 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1057 /// the resolver is no longer needed as all the relevant information is inline.
1058 impl ResolverAstLowering for Resolver<'_> {
1059 fn def_key(&mut self, id: DefId) -> DefKey {
1060 if let Some(id) = id.as_local() {
1061 self.definitions().def_key(id)
1063 self.cstore().def_key(id)
1067 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1068 self.cstore().item_generics_num_lifetimes(def_id, sess)
1071 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1072 self.partial_res_map.get(&id).cloned()
1075 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1076 self.import_res_map.get(&id).cloned().unwrap_or_default()
1079 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1080 self.label_res_map.get(&id).cloned()
1083 fn definitions(&mut self) -> &mut Definitions {
1084 &mut self.definitions
1087 fn lint_buffer(&mut self) -> &mut LintBuffer {
1088 &mut self.lint_buffer
1091 fn next_node_id(&mut self) -> NodeId {
1095 fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
1099 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1100 self.node_id_to_def_id.get(&node).copied()
1103 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1104 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1107 /// Adds a definition with a parent definition.
1111 node_id: ast::NodeId,
1117 !self.node_id_to_def_id.contains_key(&node_id),
1118 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1121 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1124 // Find the next free disambiguator for this key.
1125 let next_disambiguator = &mut self.next_disambiguator;
1126 let next_disambiguator = |parent, data| {
1127 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1128 let disambiguator = *next_disamb;
1129 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1133 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1135 assert_eq!(self.def_id_to_span.push(span), def_id);
1137 // Some things for which we allocate `LocalDefId`s don't correspond to
1138 // anything in the AST, so they don't have a `NodeId`. For these cases
1139 // we don't need a mapping from `NodeId` to `LocalDefId`.
1140 if node_id != ast::DUMMY_NODE_ID {
1141 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1142 self.node_id_to_def_id.insert(node_id, def_id);
1144 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1150 impl<'a> Resolver<'a> {
1152 session: &'a Session,
1155 metadata_loader: &'a MetadataLoaderDyn,
1156 arenas: &'a ResolverArenas<'a>,
1158 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1159 let root_def_id = root_local_def_id.to_def_id();
1160 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1161 let graph_root = arenas.alloc_module(ModuleData {
1162 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1163 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1165 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1166 let empty_module = arenas.alloc_module(ModuleData {
1167 no_implicit_prelude: true,
1176 let mut module_map = FxHashMap::default();
1177 module_map.insert(root_local_def_id, graph_root);
1179 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1180 let root = definitions.get_root_def();
1182 let mut visibilities = FxHashMap::default();
1183 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1185 let mut def_id_to_span = IndexVec::default();
1186 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1187 let mut def_id_to_node_id = IndexVec::default();
1188 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1189 let mut node_id_to_def_id = FxHashMap::default();
1190 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1192 let mut invocation_parents = FxHashMap::default();
1193 invocation_parents.insert(ExpnId::root(), root);
1195 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1199 .filter(|(_, entry)| entry.add_prelude)
1200 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1203 if !session.contains_name(&krate.attrs, sym::no_core) {
1204 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1205 if !session.contains_name(&krate.attrs, sym::no_std) {
1206 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1210 let (registered_attrs, registered_tools) =
1211 macros::registered_attrs_and_tools(session, &krate.attrs);
1213 let features = session.features_untracked();
1214 let non_macro_attr =
1215 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1217 let mut resolver = Resolver {
1222 // The outermost module has def ID 0; this is not reflected in the
1228 has_self: FxHashSet::default(),
1229 field_names: FxHashMap::default(),
1231 determined_imports: Vec::new(),
1232 indeterminate_imports: Vec::new(),
1234 last_import_segment: false,
1235 unusable_binding: None,
1237 partial_res_map: Default::default(),
1238 import_res_map: Default::default(),
1239 label_res_map: Default::default(),
1240 extern_crate_map: Default::default(),
1241 export_map: FxHashMap::default(),
1242 trait_map: Default::default(),
1243 underscore_disambiguator: 0,
1246 block_map: Default::default(),
1247 extern_module_map: FxHashMap::default(),
1248 binding_parent_modules: FxHashMap::default(),
1249 ast_transform_scopes: FxHashMap::default(),
1251 glob_map: Default::default(),
1253 used_imports: FxHashSet::default(),
1254 maybe_unused_trait_imports: Default::default(),
1255 maybe_unused_extern_crates: Vec::new(),
1257 privacy_errors: Vec::new(),
1258 ambiguity_errors: Vec::new(),
1259 use_injections: Vec::new(),
1260 macro_expanded_macro_export_errors: BTreeSet::new(),
1263 dummy_binding: arenas.alloc_name_binding(NameBinding {
1264 kind: NameBindingKind::Res(Res::Err, false),
1266 expansion: ExpnId::root(),
1268 vis: ty::Visibility::Public,
1271 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1272 macro_names: FxHashSet::default(),
1273 builtin_macros: Default::default(),
1276 macro_use_prelude: FxHashMap::default(),
1277 all_macros: FxHashMap::default(),
1278 macro_map: FxHashMap::default(),
1279 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1280 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1281 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1282 invocation_parent_scopes: Default::default(),
1283 output_macro_rules_scopes: Default::default(),
1284 helper_attrs: Default::default(),
1285 derive_resolutions: Default::default(),
1286 local_macro_def_scopes: FxHashMap::default(),
1287 name_already_seen: FxHashMap::default(),
1288 potentially_unused_imports: Vec::new(),
1289 struct_constructors: Default::default(),
1290 unused_macros: Default::default(),
1291 proc_macro_stubs: Default::default(),
1292 single_segment_macro_resolutions: Default::default(),
1293 multi_segment_macro_resolutions: Default::default(),
1294 builtin_attrs: Default::default(),
1295 containers_deriving_copy: Default::default(),
1296 active_features: features
1297 .declared_lib_features
1299 .map(|(feat, ..)| *feat)
1300 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1302 lint_buffer: LintBuffer::default(),
1303 next_node_id: NodeId::from_u32(1),
1307 placeholder_field_indices: Default::default(),
1309 next_disambiguator: Default::default(),
1310 trait_impl_items: Default::default(),
1313 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1314 resolver.invocation_parent_scopes.insert(ExpnId::root(), root_parent_scope);
1319 pub fn next_node_id(&mut self) -> NodeId {
1324 .expect("input too large; ran out of NodeIds");
1325 self.next_node_id = ast::NodeId::from_usize(next);
1329 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1330 &mut self.lint_buffer
1333 pub fn arenas() -> ResolverArenas<'a> {
1337 pub fn into_outputs(self) -> ResolverOutputs {
1338 let definitions = self.definitions;
1339 let visibilities = self.visibilities;
1340 let extern_crate_map = self.extern_crate_map;
1341 let export_map = self.export_map;
1342 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1343 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1344 let glob_map = self.glob_map;
1347 cstore: Box::new(self.crate_loader.into_cstore()),
1352 maybe_unused_trait_imports,
1353 maybe_unused_extern_crates,
1354 extern_prelude: self
1357 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1362 pub fn clone_outputs(&self) -> ResolverOutputs {
1364 definitions: self.definitions.clone(),
1365 cstore: Box::new(self.cstore().clone()),
1366 visibilities: self.visibilities.clone(),
1367 extern_crate_map: self.extern_crate_map.clone(),
1368 export_map: self.export_map.clone(),
1369 glob_map: self.glob_map.clone(),
1370 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1371 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1372 extern_prelude: self
1375 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1380 pub fn cstore(&self) -> &CStore {
1381 self.crate_loader.cstore()
1384 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1385 self.non_macro_attrs[mark_used as usize].clone()
1388 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1390 MacroKind::Bang => self.dummy_ext_bang.clone(),
1391 MacroKind::Derive => self.dummy_ext_derive.clone(),
1392 MacroKind::Attr => self.non_macro_attr(true),
1396 /// Runs the function on each namespace.
1397 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1403 fn is_builtin_macro(&mut self, res: Res) -> bool {
1404 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1407 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1409 match ctxt.outer_expn().expn_data().macro_def_id {
1410 Some(def_id) => return def_id,
1411 None => ctxt.remove_mark(),
1416 /// Entry point to crate resolution.
1417 pub fn resolve_crate(&mut self, krate: &Crate) {
1418 self.session.time("resolve_crate", || {
1419 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1420 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1421 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1422 self.session.time("resolve_check_unused", || self.check_unused(krate));
1423 self.session.time("resolve_report_errors", || self.report_errors(krate));
1424 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1428 pub fn traits_in_scope(
1430 current_trait: Option<Module<'a>>,
1431 parent_scope: &ParentScope<'a>,
1432 ctxt: SyntaxContext,
1433 assoc_item: Option<(Symbol, Namespace)>,
1434 ) -> Vec<TraitCandidate> {
1435 let mut found_traits = Vec::new();
1437 if let Some(module) = current_trait {
1438 if self.trait_may_have_item(Some(module), assoc_item) {
1439 let def_id = module.def_id().unwrap();
1440 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1444 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1446 Scope::Module(module) => {
1447 this.traits_in_module(module, assoc_item, &mut found_traits);
1449 Scope::StdLibPrelude => {
1450 if let Some(module) = this.prelude {
1451 this.traits_in_module(module, assoc_item, &mut found_traits);
1454 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1455 _ => unreachable!(),
1463 fn traits_in_module(
1466 assoc_item: Option<(Symbol, Namespace)>,
1467 found_traits: &mut Vec<TraitCandidate>,
1469 module.ensure_traits(self);
1470 let traits = module.traits.borrow();
1471 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1472 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1473 let def_id = trait_binding.res().def_id();
1474 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1475 found_traits.push(TraitCandidate { def_id, import_ids });
1480 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1481 // associated item with the given name and namespace (if specified). This is a conservative
1482 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1483 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1484 // associated items.
1485 fn trait_may_have_item(
1487 trait_module: Option<Module<'a>>,
1488 assoc_item: Option<(Symbol, Namespace)>,
1490 match (trait_module, assoc_item) {
1491 (Some(trait_module), Some((name, ns))) => {
1492 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1493 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1494 assoc_ns == ns && assoc_ident.name == name
1501 fn find_transitive_imports(
1503 mut kind: &NameBindingKind<'_>,
1505 ) -> SmallVec<[LocalDefId; 1]> {
1506 let mut import_ids = smallvec![];
1507 while let NameBindingKind::Import { import, binding, .. } = kind {
1508 let id = self.local_def_id(import.id);
1509 self.maybe_unused_trait_imports.insert(id);
1510 self.add_to_glob_map(&import, trait_name);
1511 import_ids.push(id);
1512 kind = &binding.kind;
1521 nearest_parent_mod: DefId,
1525 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1526 self.arenas.alloc_module(module)
1529 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1530 let ident = ident.normalize_to_macros_2_0();
1531 let disambiguator = if ident.name == kw::Underscore {
1532 self.underscore_disambiguator += 1;
1533 self.underscore_disambiguator
1537 BindingKey { ident, ns, disambiguator }
1540 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1541 if module.populate_on_access.get() {
1542 module.populate_on_access.set(false);
1543 self.build_reduced_graph_external(module);
1545 &module.lazy_resolutions
1552 ) -> &'a RefCell<NameResolution<'a>> {
1554 .resolutions(module)
1557 .or_insert_with(|| self.arenas.alloc_name_resolution())
1564 used_binding: &'a NameBinding<'a>,
1565 is_lexical_scope: bool,
1567 if let Some((b2, kind)) = used_binding.ambiguity {
1568 self.ambiguity_errors.push(AmbiguityError {
1573 misc1: AmbiguityErrorMisc::None,
1574 misc2: AmbiguityErrorMisc::None,
1577 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1578 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1579 // but not introduce it, as used if they are accessed from lexical scope.
1580 if is_lexical_scope {
1581 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1582 if let Some(crate_item) = entry.extern_crate_item {
1583 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1590 import.used.set(true);
1591 self.used_imports.insert((import.id, ns));
1592 self.add_to_glob_map(&import, ident);
1593 self.record_use(ident, ns, binding, false);
1598 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1599 if import.is_glob() {
1600 let def_id = self.local_def_id(import.id);
1601 self.glob_map.entry(def_id).or_default().insert(ident.name);
1605 /// A generic scope visitor.
1606 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1607 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1610 scope_set: ScopeSet,
1611 parent_scope: &ParentScope<'a>,
1612 ctxt: SyntaxContext,
1613 mut visitor: impl FnMut(
1616 /*use_prelude*/ bool,
1620 // General principles:
1621 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1622 // built into the language or standard library. This way we can add new names into the
1623 // language or standard library without breaking user code.
1624 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1625 // Places to search (in order of decreasing priority):
1627 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1628 // (open set, not controlled).
1629 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1630 // (open, not controlled).
1631 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1632 // 4. Tool modules (closed, controlled right now, but not in the future).
1633 // 5. Standard library prelude (de-facto closed, controlled).
1634 // 6. Language prelude (closed, controlled).
1636 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1637 // (open set, not controlled).
1638 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1639 // (open, not controlled).
1640 // 3. Standard library prelude (de-facto closed, controlled).
1642 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1643 // are currently reported as errors. They should be higher in priority than preludes
1644 // and probably even names in modules according to the "general principles" above. They
1645 // also should be subject to restricted shadowing because are effectively produced by
1646 // derives (you need to resolve the derive first to add helpers into scope), but they
1647 // should be available before the derive is expanded for compatibility.
1648 // It's mess in general, so we are being conservative for now.
1649 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1650 // priority than prelude macros, but create ambiguities with macros in modules.
1651 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1652 // (open, not controlled). Have higher priority than prelude macros, but create
1653 // ambiguities with `macro_rules`.
1654 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1655 // 4a. User-defined prelude from macro-use
1656 // (open, the open part is from macro expansions, not controlled).
1657 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1658 // 4c. Standard library prelude (de-facto closed, controlled).
1659 // 6. Language prelude: builtin attributes (closed, controlled).
1661 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1662 let (ns, macro_kind, is_absolute_path) = match scope_set {
1663 ScopeSet::All(ns, _) => (ns, None, false),
1664 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1665 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1667 // Jump out of trait or enum modules, they do not act as scopes.
1668 let module = parent_scope.module.nearest_item_scope();
1669 let mut scope = match ns {
1670 _ if is_absolute_path => Scope::CrateRoot,
1671 TypeNS | ValueNS => Scope::Module(module),
1672 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1674 let mut ctxt = ctxt.normalize_to_macros_2_0();
1675 let mut use_prelude = !module.no_implicit_prelude;
1678 let visit = match scope {
1679 // Derive helpers are not in scope when resolving derives in the same container.
1680 Scope::DeriveHelpers(expn_id) => {
1681 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1683 Scope::DeriveHelpersCompat => true,
1684 Scope::MacroRules(macro_rules_scope) => {
1685 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1686 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1687 // As another consequence of this optimization visitors never observe invocation
1688 // scopes for macros that were already expanded.
1689 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1690 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1691 macro_rules_scope.set(next_scope.get());
1698 Scope::CrateRoot => true,
1699 Scope::Module(..) => true,
1700 Scope::RegisteredAttrs => use_prelude,
1701 Scope::MacroUsePrelude => use_prelude || rust_2015,
1702 Scope::BuiltinAttrs => true,
1703 Scope::ExternPrelude => use_prelude || is_absolute_path,
1704 Scope::ToolPrelude => use_prelude,
1705 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1706 Scope::BuiltinTypes => true,
1710 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1711 return break_result;
1715 scope = match scope {
1716 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1717 // Derive helpers are not visible to code generated by bang or derive macros.
1718 let expn_data = expn_id.expn_data();
1719 match expn_data.kind {
1721 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1722 Scope::DeriveHelpersCompat
1724 _ => Scope::DeriveHelpers(expn_data.parent),
1727 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1728 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1729 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1730 MacroRulesScope::Binding(binding) => {
1731 Scope::MacroRules(binding.parent_macro_rules_scope)
1733 MacroRulesScope::Invocation(invoc_id) => {
1734 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1736 MacroRulesScope::Empty => Scope::Module(module),
1738 Scope::CrateRoot => match ns {
1740 ctxt.adjust(ExpnId::root());
1741 Scope::ExternPrelude
1743 ValueNS | MacroNS => break,
1745 Scope::Module(module) => {
1746 use_prelude = !module.no_implicit_prelude;
1747 match self.hygienic_lexical_parent(module, &mut ctxt) {
1748 Some(parent_module) => Scope::Module(parent_module),
1750 ctxt.adjust(ExpnId::root());
1752 TypeNS => Scope::ExternPrelude,
1753 ValueNS => Scope::StdLibPrelude,
1754 MacroNS => Scope::RegisteredAttrs,
1759 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1760 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1761 Scope::BuiltinAttrs => break, // nowhere else to search
1762 Scope::ExternPrelude if is_absolute_path => break,
1763 Scope::ExternPrelude => Scope::ToolPrelude,
1764 Scope::ToolPrelude => Scope::StdLibPrelude,
1765 Scope::StdLibPrelude => match ns {
1766 TypeNS => Scope::BuiltinTypes,
1767 ValueNS => break, // nowhere else to search
1768 MacroNS => Scope::BuiltinAttrs,
1770 Scope::BuiltinTypes => break, // nowhere else to search
1777 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1778 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1779 /// `ident` in the first scope that defines it (or None if no scopes define it).
1781 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1782 /// the items are defined in the block. For example,
1785 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1788 /// g(); // This resolves to the local variable `g` since it shadows the item.
1792 /// Invariant: This must only be called during main resolution, not during
1793 /// import resolution.
1794 fn resolve_ident_in_lexical_scope(
1798 parent_scope: &ParentScope<'a>,
1799 record_used_id: Option<NodeId>,
1802 ) -> Option<LexicalScopeBinding<'a>> {
1803 assert!(ns == TypeNS || ns == ValueNS);
1804 if ident.name == kw::Empty {
1805 return Some(LexicalScopeBinding::Res(Res::Err));
1807 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1808 // FIXME(jseyfried) improve `Self` hygiene
1809 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1810 (empty_span, empty_span)
1811 } else if ns == TypeNS {
1812 let normalized_span = ident.span.normalize_to_macros_2_0();
1813 (normalized_span, normalized_span)
1815 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1817 ident.span = general_span;
1818 let normalized_ident = Ident { span: normalized_span, ..ident };
1820 // Walk backwards up the ribs in scope.
1821 let record_used = record_used_id.is_some();
1822 let mut module = self.graph_root;
1823 for i in (0..ribs.len()).rev() {
1824 debug!("walk rib\n{:?}", ribs[i].bindings);
1825 // Use the rib kind to determine whether we are resolving parameters
1826 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1827 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1828 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1830 // The ident resolves to a type parameter or local variable.
1831 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1837 *original_rib_ident_def,
1842 module = match ribs[i].kind {
1843 ModuleRibKind(module) => module,
1844 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1845 // If an invocation of this macro created `ident`, give up on `ident`
1846 // and switch to `ident`'s source from the macro definition.
1847 ident.span.remove_mark();
1853 let item = self.resolve_ident_in_module_unadjusted(
1854 ModuleOrUniformRoot::Module(module),
1861 if let Ok(binding) = item {
1862 // The ident resolves to an item.
1863 return Some(LexicalScopeBinding::Item(binding));
1867 ModuleKind::Block(..) => {} // We can see through blocks
1872 ident = normalized_ident;
1873 let mut poisoned = None;
1875 let mut span_data = ident.span.data();
1876 let opt_module = if let Some(node_id) = record_used_id {
1877 self.hygienic_lexical_parent_with_compatibility_fallback(
1879 &mut span_data.ctxt,
1884 self.hygienic_lexical_parent(module, &mut span_data.ctxt)
1886 ident.span = span_data.span();
1887 module = unwrap_or!(opt_module, break);
1888 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1889 let result = self.resolve_ident_in_module_unadjusted(
1890 ModuleOrUniformRoot::Module(module),
1893 adjusted_parent_scope,
1900 if let Some(node_id) = poisoned {
1901 self.lint_buffer.buffer_lint_with_diagnostic(
1902 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1905 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1906 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1909 return Some(LexicalScopeBinding::Item(binding));
1911 Err(Determined) => continue,
1912 Err(Undetermined) => {
1913 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1918 if !module.no_implicit_prelude {
1919 ident.span.adjust(ExpnId::root());
1921 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1922 return Some(LexicalScopeBinding::Item(binding));
1924 if let Some(ident) = self.registered_tools.get(&ident) {
1926 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1927 .to_name_binding(self.arenas);
1928 return Some(LexicalScopeBinding::Item(binding));
1931 if let Some(prelude) = self.prelude {
1932 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1933 ModuleOrUniformRoot::Module(prelude),
1940 return Some(LexicalScopeBinding::Item(binding));
1946 if let Some(prim_ty) = PrimTy::from_name(ident.name) {
1948 (Res::PrimTy(prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1949 .to_name_binding(self.arenas);
1950 return Some(LexicalScopeBinding::Item(binding));
1957 fn hygienic_lexical_parent(
1960 ctxt: &mut SyntaxContext,
1961 ) -> Option<Module<'a>> {
1962 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
1963 return Some(self.macro_def_scope(ctxt.remove_mark()));
1966 if let ModuleKind::Block(..) = module.kind {
1967 return Some(module.parent.unwrap().nearest_item_scope());
1973 fn hygienic_lexical_parent_with_compatibility_fallback(
1976 ctxt: &mut SyntaxContext,
1978 poisoned: &mut Option<NodeId>,
1979 ) -> Option<Module<'a>> {
1980 if let module @ Some(..) = self.hygienic_lexical_parent(module, ctxt) {
1984 // We need to support the next case under a deprecation warning
1987 // ---- begin: this comes from a proc macro derive
1988 // mod implementation_details {
1989 // // Note that `MyStruct` is not in scope here.
1990 // impl SomeTrait for MyStruct { ... }
1994 // So we have to fall back to the module's parent during lexical resolution in this case.
1995 if let Some(parent) = module.parent {
1996 // Inner module is inside the macro, parent module is outside of the macro.
1997 if module.expansion != parent.expansion
1998 && module.expansion.is_descendant_of(parent.expansion)
2000 // The macro is a proc macro derive
2001 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2002 let ext = self.get_macro_by_def_id(def_id);
2003 if ext.builtin_name.is_none()
2004 && ext.macro_kind() == MacroKind::Derive
2005 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2007 *poisoned = Some(node_id);
2008 return module.parent;
2017 fn resolve_ident_in_module(
2019 module: ModuleOrUniformRoot<'a>,
2022 parent_scope: &ParentScope<'a>,
2025 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2026 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2027 .map_err(|(determinacy, _)| determinacy)
2030 fn resolve_ident_in_module_ext(
2032 module: ModuleOrUniformRoot<'a>,
2035 parent_scope: &ParentScope<'a>,
2038 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2039 let tmp_parent_scope;
2040 let mut adjusted_parent_scope = parent_scope;
2042 ModuleOrUniformRoot::Module(m) => {
2043 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2045 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2046 adjusted_parent_scope = &tmp_parent_scope;
2049 ModuleOrUniformRoot::ExternPrelude => {
2050 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2052 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2056 self.resolve_ident_in_module_unadjusted_ext(
2060 adjusted_parent_scope,
2067 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2068 debug!("resolve_crate_root({:?})", ident);
2069 let mut ctxt = ident.span.ctxt();
2070 let mark = if ident.name == kw::DollarCrate {
2071 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2072 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2073 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2074 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2075 // definitions actually produced by `macro` and `macro` definitions produced by
2076 // `macro_rules!`, but at least such configurations are not stable yet.
2077 ctxt = ctxt.normalize_to_macro_rules();
2079 "resolve_crate_root: marks={:?}",
2080 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2082 let mut iter = ctxt.marks().into_iter().rev().peekable();
2083 let mut result = None;
2084 // Find the last opaque mark from the end if it exists.
2085 while let Some(&(mark, transparency)) = iter.peek() {
2086 if transparency == Transparency::Opaque {
2087 result = Some(mark);
2094 "resolve_crate_root: found opaque mark {:?} {:?}",
2096 result.map(|r| r.expn_data())
2098 // Then find the last semi-transparent mark from the end if it exists.
2099 for (mark, transparency) in iter {
2100 if transparency == Transparency::SemiTransparent {
2101 result = Some(mark);
2107 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2109 result.map(|r| r.expn_data())
2113 debug!("resolve_crate_root: not DollarCrate");
2114 ctxt = ctxt.normalize_to_macros_2_0();
2115 ctxt.adjust(ExpnId::root())
2117 let module = match mark {
2118 Some(def) => self.macro_def_scope(def),
2121 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2124 return self.graph_root;
2127 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2129 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2138 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2139 let mut module = self.get_module(module.nearest_parent_mod);
2140 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2141 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2142 module = self.get_module(parent.nearest_parent_mod);
2150 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2151 parent_scope: &ParentScope<'a>,
2154 crate_lint: CrateLint,
2155 ) -> PathResult<'a> {
2156 self.resolve_path_with_ribs(
2167 fn resolve_path_with_ribs(
2170 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2171 parent_scope: &ParentScope<'a>,
2174 crate_lint: CrateLint,
2175 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2176 ) -> PathResult<'a> {
2177 let mut module = None;
2178 let mut allow_super = true;
2179 let mut second_binding = None;
2182 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2183 path_span={:?}, crate_lint={:?})",
2184 path, opt_ns, record_used, path_span, crate_lint,
2187 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2188 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2189 let record_segment_res = |this: &mut Self, res| {
2191 if let Some(id) = id {
2192 if !this.partial_res_map.contains_key(&id) {
2193 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2194 this.record_partial_res(id, PartialRes::new(res));
2200 let is_last = i == path.len() - 1;
2201 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2202 let name = ident.name;
2204 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2207 if allow_super && name == kw::Super {
2208 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2209 let self_module = match i {
2210 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2212 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2216 if let Some(self_module) = self_module {
2217 if let Some(parent) = self_module.parent {
2218 module = Some(ModuleOrUniformRoot::Module(
2219 self.resolve_self(&mut ctxt, parent),
2224 let msg = "there are too many leading `super` keywords".to_string();
2225 return PathResult::Failed {
2229 is_error_from_last_segment: false,
2233 if name == kw::SelfLower {
2234 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2235 module = Some(ModuleOrUniformRoot::Module(
2236 self.resolve_self(&mut ctxt, parent_scope.module),
2240 if name == kw::PathRoot && ident.span.rust_2018() {
2241 module = Some(ModuleOrUniformRoot::ExternPrelude);
2244 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2245 // `::a::b` from 2015 macro on 2018 global edition
2246 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2249 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2250 // `::a::b`, `crate::a::b` or `$crate::a::b`
2251 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2257 // Report special messages for path segment keywords in wrong positions.
2258 if ident.is_path_segment_keyword() && i != 0 {
2259 let name_str = if name == kw::PathRoot {
2260 "crate root".to_string()
2262 format!("`{}`", name)
2264 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2265 format!("global paths cannot start with {}", name_str)
2267 format!("{} in paths can only be used in start position", name_str)
2269 return PathResult::Failed {
2273 is_error_from_last_segment: false,
2277 enum FindBindingResult<'a> {
2278 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2279 PathResult(PathResult<'a>),
2281 let find_binding_in_ns = |this: &mut Self, ns| {
2282 let binding = if let Some(module) = module {
2283 this.resolve_ident_in_module(
2291 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2292 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2293 this.early_resolve_ident_in_lexical_scope(
2302 let record_used_id = if record_used {
2303 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2307 match this.resolve_ident_in_lexical_scope(
2315 // we found a locally-imported or available item/module
2316 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2317 // we found a local variable or type param
2318 Some(LexicalScopeBinding::Res(res))
2319 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2321 record_segment_res(this, res);
2322 return FindBindingResult::PathResult(PathResult::NonModule(
2323 PartialRes::with_unresolved_segments(res, path.len() - 1),
2326 _ => Err(Determinacy::determined(record_used)),
2329 FindBindingResult::Binding(binding)
2331 let binding = match find_binding_in_ns(self, ns) {
2332 FindBindingResult::PathResult(x) => return x,
2333 FindBindingResult::Binding(binding) => binding,
2338 second_binding = Some(binding);
2340 let res = binding.res();
2341 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2342 if let Some(next_module) = binding.module() {
2343 module = Some(ModuleOrUniformRoot::Module(next_module));
2344 record_segment_res(self, res);
2345 } else if res == Res::ToolMod && i + 1 != path.len() {
2346 if binding.is_import() {
2350 "cannot use a tool module through an import",
2352 .span_note(binding.span, "the tool module imported here")
2355 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2356 return PathResult::NonModule(PartialRes::new(res));
2357 } else if res == Res::Err {
2358 return PathResult::NonModule(PartialRes::new(Res::Err));
2359 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2360 self.lint_if_path_starts_with_module(
2366 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2371 let label = format!(
2372 "`{}` is {} {}, not a module",
2378 return PathResult::Failed {
2382 is_error_from_last_segment: is_last,
2386 Err(Undetermined) => return PathResult::Indeterminate,
2387 Err(Determined) => {
2388 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2389 if opt_ns.is_some() && !module.is_normal() {
2390 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2391 module.res().unwrap(),
2396 let module_res = match module {
2397 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2400 let (label, suggestion) = if module_res == self.graph_root.res() {
2401 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2402 // Don't look up import candidates if this is a speculative resolve
2403 let mut candidates = if record_used {
2404 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2408 candidates.sort_by_cached_key(|c| {
2409 (c.path.segments.len(), pprust::path_to_string(&c.path))
2411 if let Some(candidate) = candidates.get(0) {
2413 String::from("unresolved import"),
2415 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2416 String::from("a similar path exists"),
2417 Applicability::MaybeIncorrect,
2421 (format!("maybe a missing crate `{}`?", ident), None)
2429 .map_or(false, |c| c.is_ascii_uppercase())
2431 (format!("use of undeclared type `{}`", ident), None)
2433 (format!("use of undeclared crate or module `{}`", ident), None)
2436 let parent = path[i - 1].ident.name;
2437 let parent = if parent == kw::PathRoot {
2438 "crate root".to_owned()
2440 format!("`{}`", parent)
2443 let mut msg = format!("could not find `{}` in {}", ident, parent);
2444 if ns == TypeNS || ns == ValueNS {
2445 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2446 if let FindBindingResult::Binding(Ok(binding)) =
2447 find_binding_in_ns(self, ns_to_try)
2449 let mut found = |what| {
2451 "expected {}, found {} `{}` in {}",
2458 if binding.module().is_some() {
2461 match binding.res() {
2462 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2463 _ => found(ns_to_try.descr()),
2470 return PathResult::Failed {
2474 is_error_from_last_segment: is_last,
2480 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2482 PathResult::Module(match module {
2483 Some(module) => module,
2484 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2485 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2489 fn lint_if_path_starts_with_module(
2491 crate_lint: CrateLint,
2494 second_binding: Option<&NameBinding<'_>>,
2496 let (diag_id, diag_span) = match crate_lint {
2497 CrateLint::No => return,
2498 CrateLint::SimplePath(id) => (id, path_span),
2499 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2500 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2503 let first_name = match path.get(0) {
2504 // In the 2018 edition this lint is a hard error, so nothing to do
2505 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2509 // We're only interested in `use` paths which should start with
2510 // `{{root}}` currently.
2511 if first_name != kw::PathRoot {
2516 // If this import looks like `crate::...` it's already good
2517 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2518 // Otherwise go below to see if it's an extern crate
2520 // If the path has length one (and it's `PathRoot` most likely)
2521 // then we don't know whether we're gonna be importing a crate or an
2522 // item in our crate. Defer this lint to elsewhere
2526 // If the first element of our path was actually resolved to an
2527 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2528 // warning, this looks all good!
2529 if let Some(binding) = second_binding {
2530 if let NameBindingKind::Import { import, .. } = binding.kind {
2531 // Careful: we still want to rewrite paths from renamed extern crates.
2532 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2538 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2539 self.lint_buffer.buffer_lint_with_diagnostic(
2540 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2543 "absolute paths must start with `self`, `super`, \
2544 `crate`, or an external crate name in the 2018 edition",
2549 // Validate a local resolution (from ribs).
2550 fn validate_res_from_ribs(
2557 original_rib_ident_def: Ident,
2558 all_ribs: &[Rib<'a>],
2560 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2561 debug!("validate_res_from_ribs({:?})", res);
2562 let ribs = &all_ribs[rib_index + 1..];
2564 // An invalid forward use of a type parameter from a previous default.
2565 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2567 let res_error = if rib_ident.name == kw::SelfUpper {
2568 ResolutionError::SelfInTyParamDefault
2570 ResolutionError::ForwardDeclaredTyParam
2572 self.report_error(span, res_error);
2574 assert_eq!(res, Res::Err);
2580 use ResolutionError::*;
2581 let mut res_err = None;
2586 | ClosureOrAsyncRibKind
2588 | MacroDefinition(..)
2589 | ForwardTyParamBanRibKind => {
2590 // Nothing to do. Continue.
2592 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2593 // This was an attempt to access an upvar inside a
2594 // named function item. This is not allowed, so we
2597 // We don't immediately trigger a resolve error, because
2598 // we want certain other resolution errors (namely those
2599 // emitted for `ConstantItemRibKind` below) to take
2601 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2604 ConstantItemRibKind(_, item) => {
2605 // Still doesn't deal with upvars
2607 let (span, resolution_error) =
2608 if let Some((ident, constant_item_kind)) = item {
2609 let kind_str = match constant_item_kind {
2610 ConstantItemKind::Const => "const",
2611 ConstantItemKind::Static => "static",
2615 AttemptToUseNonConstantValueInConstant(
2616 ident, "let", kind_str,
2622 AttemptToUseNonConstantValueInConstant(
2623 original_rib_ident_def,
2629 self.report_error(span, resolution_error);
2633 ConstParamTyRibKind => {
2635 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2641 if let Some(res_err) = res_err {
2642 self.report_error(span, res_err);
2646 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2647 let mut in_ty_param_default = false;
2649 let has_generic_params = match rib.kind {
2651 | ClosureOrAsyncRibKind
2654 | MacroDefinition(..) => {
2655 // Nothing to do. Continue.
2659 // We only forbid constant items if we are inside of type defaults,
2660 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2661 ForwardTyParamBanRibKind => {
2662 in_ty_param_default = true;
2665 ConstantItemRibKind(trivial, _) => {
2666 let features = self.session.features_untracked();
2667 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2669 || features.const_generics
2670 || features.lazy_normalization_consts)
2672 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2673 // we can't easily tell if it's generic at this stage, so we instead remember
2674 // this and then enforce the self type to be concrete later on.
2675 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2676 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2681 ResolutionError::ParamInNonTrivialAnonConst {
2682 name: rib_ident.name,
2688 self.session.delay_span_bug(span, CG_BUG_STR);
2693 if in_ty_param_default {
2697 ResolutionError::ParamInAnonConstInTyDefault(
2708 // This was an attempt to use a type parameter outside its scope.
2709 ItemRibKind(has_generic_params) => has_generic_params,
2710 FnItemRibKind => HasGenericParams::Yes,
2711 ConstParamTyRibKind => {
2715 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2725 ResolutionError::GenericParamsFromOuterFunction(
2734 Res::Def(DefKind::ConstParam, _) => {
2735 let mut ribs = ribs.iter().peekable();
2736 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2737 // When declaring const parameters inside function signatures, the first rib
2738 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2739 // (spuriously) conflicting with the const param.
2743 let mut in_ty_param_default = false;
2745 let has_generic_params = match rib.kind {
2747 | ClosureOrAsyncRibKind
2750 | MacroDefinition(..) => continue,
2752 // We only forbid constant items if we are inside of type defaults,
2753 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2754 ForwardTyParamBanRibKind => {
2755 in_ty_param_default = true;
2758 ConstantItemRibKind(trivial, _) => {
2759 let features = self.session.features_untracked();
2760 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2762 || features.const_generics
2763 || features.lazy_normalization_consts)
2768 ResolutionError::ParamInNonTrivialAnonConst {
2769 name: rib_ident.name,
2775 self.session.delay_span_bug(span, CG_BUG_STR);
2779 if in_ty_param_default {
2783 ResolutionError::ParamInAnonConstInTyDefault(
2794 ItemRibKind(has_generic_params) => has_generic_params,
2795 FnItemRibKind => HasGenericParams::Yes,
2796 ConstParamTyRibKind => {
2800 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2807 // This was an attempt to use a const parameter outside its scope.
2811 ResolutionError::GenericParamsFromOuterFunction(
2825 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2826 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2827 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2828 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2832 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2833 vis.is_accessible_from(module.nearest_parent_mod, self)
2836 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2837 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2838 if !ptr::eq(module, old_module) {
2839 span_bug!(binding.span, "parent module is reset for binding");
2844 fn disambiguate_macro_rules_vs_modularized(
2846 macro_rules: &'a NameBinding<'a>,
2847 modularized: &'a NameBinding<'a>,
2849 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2850 // is disambiguated to mitigate regressions from macro modularization.
2851 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2853 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2854 self.binding_parent_modules.get(&PtrKey(modularized)),
2856 (Some(macro_rules), Some(modularized)) => {
2857 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2858 && modularized.is_ancestor_of(macro_rules)
2864 fn report_errors(&mut self, krate: &Crate) {
2865 self.report_with_use_injections(krate);
2867 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2868 let msg = "macro-expanded `macro_export` macros from the current crate \
2869 cannot be referred to by absolute paths";
2870 self.lint_buffer.buffer_lint_with_diagnostic(
2871 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2875 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2879 for ambiguity_error in &self.ambiguity_errors {
2880 self.report_ambiguity_error(ambiguity_error);
2883 let mut reported_spans = FxHashSet::default();
2884 for error in &self.privacy_errors {
2885 if reported_spans.insert(error.dedup_span) {
2886 self.report_privacy_error(error);
2891 fn report_with_use_injections(&mut self, krate: &Crate) {
2892 for UseError { mut err, candidates, def_id, instead, suggestion } in
2893 self.use_injections.drain(..)
2895 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2896 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2900 if !candidates.is_empty() {
2901 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2902 } else if let Some((span, msg, sugg, appl)) = suggestion {
2903 err.span_suggestion(span, msg, sugg, appl);
2909 fn report_conflict<'b>(
2914 new_binding: &NameBinding<'b>,
2915 old_binding: &NameBinding<'b>,
2917 // Error on the second of two conflicting names
2918 if old_binding.span.lo() > new_binding.span.lo() {
2919 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2922 let container = match parent.kind {
2923 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2924 ModuleKind::Block(..) => "block",
2927 let old_noun = match old_binding.is_import() {
2929 false => "definition",
2932 let new_participle = match new_binding.is_import() {
2938 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2940 if let Some(s) = self.name_already_seen.get(&name) {
2946 let old_kind = match (ns, old_binding.module()) {
2947 (ValueNS, _) => "value",
2948 (MacroNS, _) => "macro",
2949 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2950 (TypeNS, Some(module)) if module.is_normal() => "module",
2951 (TypeNS, Some(module)) if module.is_trait() => "trait",
2952 (TypeNS, _) => "type",
2955 let msg = format!("the name `{}` is defined multiple times", name);
2957 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2958 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2959 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2960 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2961 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2963 _ => match (old_binding.is_import(), new_binding.is_import()) {
2964 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2965 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2966 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2971 "`{}` must be defined only once in the {} namespace of this {}",
2977 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2979 self.session.source_map().guess_head_span(old_binding.span),
2980 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2983 // See https://github.com/rust-lang/rust/issues/32354
2984 use NameBindingKind::Import;
2985 let import = match (&new_binding.kind, &old_binding.kind) {
2986 // If there are two imports where one or both have attributes then prefer removing the
2987 // import without attributes.
2988 (Import { import: new, .. }, Import { import: old, .. })
2990 !new_binding.span.is_dummy()
2991 && !old_binding.span.is_dummy()
2992 && (new.has_attributes || old.has_attributes)
2995 if old.has_attributes {
2996 Some((new, new_binding.span, true))
2998 Some((old, old_binding.span, true))
3001 // Otherwise prioritize the new binding.
3002 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3003 Some((import, new_binding.span, other.is_import()))
3005 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3006 Some((import, old_binding.span, other.is_import()))
3011 // Check if the target of the use for both bindings is the same.
3012 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3013 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3015 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3016 // Only suggest removing an import if both bindings are to the same def, if both spans
3017 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3018 // been introduced by a item.
3019 let should_remove_import = duplicate
3021 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3024 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3025 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3027 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3028 // Simple case - remove the entire import. Due to the above match arm, this can
3029 // only be a single use so just remove it entirely.
3030 err.tool_only_span_suggestion(
3031 import.use_span_with_attributes,
3032 "remove unnecessary import",
3034 Applicability::MaybeIncorrect,
3037 Some((import, span, _)) => {
3038 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3044 self.name_already_seen.insert(name, span);
3047 /// This function adds a suggestion to change the binding name of a new import that conflicts
3048 /// with an existing import.
3050 /// ```text,ignore (diagnostic)
3051 /// help: you can use `as` to change the binding name of the import
3053 /// LL | use foo::bar as other_bar;
3054 /// | ^^^^^^^^^^^^^^^^^^^^^
3056 fn add_suggestion_for_rename_of_use(
3058 err: &mut DiagnosticBuilder<'_>,
3060 import: &Import<'_>,
3063 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3064 format!("Other{}", name)
3066 format!("other_{}", name)
3069 let mut suggestion = None;
3071 ImportKind::Single { type_ns_only: true, .. } => {
3072 suggestion = Some(format!("self as {}", suggested_name))
3074 ImportKind::Single { source, .. } => {
3076 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3078 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3079 if pos <= snippet.len() {
3080 suggestion = Some(format!(
3084 if snippet.ends_with(';') { ";" } else { "" }
3090 ImportKind::ExternCrate { source, target, .. } => {
3091 suggestion = Some(format!(
3092 "extern crate {} as {};",
3093 source.unwrap_or(target.name),
3097 _ => unreachable!(),
3100 let rename_msg = "you can use `as` to change the binding name of the import";
3101 if let Some(suggestion) = suggestion {
3102 err.span_suggestion(
3106 Applicability::MaybeIncorrect,
3109 err.span_label(binding_span, rename_msg);
3113 /// This function adds a suggestion to remove a unnecessary binding from an import that is
3114 /// nested. In the following example, this function will be invoked to remove the `a` binding
3115 /// in the second use statement:
3117 /// ```ignore (diagnostic)
3118 /// use issue_52891::a;
3119 /// use issue_52891::{d, a, e};
3122 /// The following suggestion will be added:
3124 /// ```ignore (diagnostic)
3125 /// use issue_52891::{d, a, e};
3126 /// ^-- help: remove unnecessary import
3129 /// If the nested use contains only one import then the suggestion will remove the entire
3132 /// It is expected that the provided import is nested - this isn't checked by the
3133 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3134 /// as characters expected by span manipulations won't be present.
3135 fn add_suggestion_for_duplicate_nested_use(
3137 err: &mut DiagnosticBuilder<'_>,
3138 import: &Import<'_>,
3141 assert!(import.is_nested());
3142 let message = "remove unnecessary import";
3144 // Two examples will be used to illustrate the span manipulations we're doing:
3146 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3147 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3148 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3149 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3151 let (found_closing_brace, span) =
3152 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3154 // If there was a closing brace then identify the span to remove any trailing commas from
3155 // previous imports.
3156 if found_closing_brace {
3157 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3158 err.tool_only_span_suggestion(
3162 Applicability::MaybeIncorrect,
3165 // Remove the entire line if we cannot extend the span back, this indicates a
3166 // `issue_52891::{self}` case.
3167 err.span_suggestion(
3168 import.use_span_with_attributes,
3171 Applicability::MaybeIncorrect,
3178 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3181 fn extern_prelude_get(
3185 ) -> Option<&'a NameBinding<'a>> {
3186 if ident.is_path_segment_keyword() {
3187 // Make sure `self`, `super` etc produce an error when passed to here.
3190 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3191 if let Some(binding) = entry.extern_crate_item {
3192 if !speculative && entry.introduced_by_item {
3193 self.record_use(ident, TypeNS, binding, false);
3197 let crate_id = if !speculative {
3198 self.crate_loader.process_path_extern(ident.name, ident.span)
3200 self.crate_loader.maybe_process_path_extern(ident.name)?
3202 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3204 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3205 .to_name_binding(self.arenas),
3211 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3212 /// isn't something that can be returned because it can't be made to live that long,
3213 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3214 /// just that an error occurred.
3215 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3216 pub fn resolve_str_path_error(
3222 ) -> Result<(ast::Path, Res), ()> {
3223 let path = if path_str.starts_with("::") {
3226 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3227 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3228 .map(|i| self.new_ast_path_segment(i))
3237 .map(Ident::from_str)
3238 .map(|i| self.new_ast_path_segment(i))
3243 let module = self.get_module(module_id);
3244 let parent_scope = &ParentScope::module(module, self);
3245 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3249 // Resolve a path passed from rustdoc or HIR lowering.
3250 fn resolve_ast_path(
3254 parent_scope: &ParentScope<'a>,
3255 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3256 match self.resolve_path(
3257 &Segment::from_path(path),
3264 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3265 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3266 Ok(path_res.base_res())
3268 PathResult::NonModule(..) => Err((
3270 ResolutionError::FailedToResolve {
3271 label: String::from("type-relative paths are not supported in this context"),
3275 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3276 PathResult::Failed { span, label, suggestion, .. } => {
3277 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3282 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3283 let mut seg = ast::PathSegment::from_ident(ident);
3284 seg.id = self.next_node_id();
3289 pub fn graph_root(&self) -> Module<'a> {
3294 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3298 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3300 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3301 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3305 fn names_to_string(names: &[Symbol]) -> String {
3306 let mut result = String::new();
3307 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3309 result.push_str("::");
3311 if Ident::with_dummy_span(*name).is_raw_guess() {
3312 result.push_str("r#");
3314 result.push_str(&name.as_str());
3319 fn path_names_to_string(path: &Path) -> String {
3320 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3323 /// A somewhat inefficient routine to obtain the name of a module.
3324 fn module_to_string(module: Module<'_>) -> Option<String> {
3325 let mut names = Vec::new();
3327 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3328 if let ModuleKind::Def(.., name) = module.kind {
3329 if let Some(parent) = module.parent {
3331 collect_mod(names, parent);
3334 names.push(Symbol::intern("<opaque>"));
3335 collect_mod(names, module.parent.unwrap());
3338 collect_mod(&mut names, module);
3340 if names.is_empty() {
3344 Some(names_to_string(&names))
3347 #[derive(Copy, Clone, Debug)]
3349 /// Do not issue the lint.
3352 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3353 /// In this case, we can take the span of that path.
3356 /// This lint comes from a `use` statement. In this case, what we
3357 /// care about really is the *root* `use` statement; e.g., if we
3358 /// have nested things like `use a::{b, c}`, we care about the
3360 UsePath { root_id: NodeId, root_span: Span },
3362 /// This is the "trait item" from a fully qualified path. For example,
3363 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3364 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3365 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3369 fn node_id(&self) -> Option<NodeId> {
3371 CrateLint::No => None,
3372 CrateLint::SimplePath(id)
3373 | CrateLint::UsePath { root_id: id, .. }
3374 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3379 pub fn provide(providers: &mut Providers) {
3380 late::lifetimes::provide(providers);