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(bool_to_option)]
13 #![feature(crate_visibility_modifier)]
14 #![feature(format_args_capture)]
16 #![feature(or_patterns)]
17 #![recursion_limit = "256"]
19 pub use rustc_hir::def::{Namespace, PerNS};
23 use rustc_arena::{DroplessArena, TypedArena};
24 use rustc_ast::node_id::NodeMap;
25 use rustc_ast::unwrap_or;
26 use rustc_ast::visit::{self, Visitor};
27 use rustc_ast::{self as ast, FloatTy, IntTy, NodeId, UintTy};
28 use rustc_ast::{Crate, CRATE_NODE_ID};
29 use rustc_ast::{ItemKind, Path};
30 use rustc_ast_lowering::ResolverAstLowering;
31 use rustc_ast_pretty::pprust;
32 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
33 use rustc_data_structures::ptr_key::PtrKey;
34 use rustc_data_structures::sync::Lrc;
35 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
36 use rustc_expand::base::SyntaxExtension;
37 use rustc_hir::def::Namespace::*;
38 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
39 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
40 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
41 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
42 use rustc_hir::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::ty::query::Providers;
48 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
49 use rustc_middle::{bug, span_bug};
50 use rustc_session::lint;
51 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
52 use rustc_session::Session;
53 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
54 use rustc_span::source_map::Spanned;
55 use rustc_span::symbol::{kw, sym, Ident, Symbol};
56 use rustc_span::{Span, DUMMY_SP};
58 use smallvec::{smallvec, SmallVec};
59 use std::cell::{Cell, RefCell};
60 use std::collections::BTreeSet;
61 use std::{cmp, fmt, iter, ptr};
64 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
65 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
66 use imports::{Import, ImportKind, ImportResolver, NameResolution};
67 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
68 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
70 type Res = def::Res<NodeId>;
72 mod build_reduced_graph;
85 #[derive(Copy, Clone, PartialEq, Debug)]
86 pub enum Determinacy {
92 fn determined(determined: bool) -> Determinacy {
93 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
97 /// A specific scope in which a name can be looked up.
98 /// This enum is currently used only for early resolution (imports and macros),
99 /// but not for late resolution yet.
100 #[derive(Clone, Copy)]
102 DeriveHelpers(ExpnId),
104 MacroRules(MacroRulesScopeRef<'a>),
116 /// Names from different contexts may want to visit different subsets of all specific scopes
117 /// with different restrictions when looking up the resolution.
118 /// This enum is currently used only for early resolution (imports and macros),
119 /// but not for late resolution yet.
121 /// All scopes with the given namespace.
122 All(Namespace, /*is_import*/ bool),
123 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
124 AbsolutePath(Namespace),
125 /// All scopes with macro namespace and the given macro kind restriction.
129 /// Everything you need to know about a name's location to resolve it.
130 /// Serves as a starting point for the scope visitor.
131 /// This struct is currently used only for early resolution (imports and macros),
132 /// but not for late resolution yet.
133 #[derive(Clone, Copy, Debug)]
134 pub struct ParentScope<'a> {
137 macro_rules: MacroRulesScopeRef<'a>,
138 derives: &'a [ast::Path],
141 impl<'a> ParentScope<'a> {
142 /// Creates a parent scope with the passed argument used as the module scope component,
143 /// and other scope components set to default empty values.
144 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
147 expansion: ExpnId::root(),
148 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
155 struct BindingError {
157 origin: BTreeSet<Span>,
158 target: BTreeSet<Span>,
162 impl PartialOrd for BindingError {
163 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
164 Some(self.cmp(other))
168 impl PartialEq for BindingError {
169 fn eq(&self, other: &BindingError) -> bool {
170 self.name == other.name
174 impl Ord for BindingError {
175 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
176 self.name.cmp(&other.name)
180 enum ResolutionError<'a> {
181 /// Error E0401: can't use type or const parameters from outer function.
182 GenericParamsFromOuterFunction(Res, HasGenericParams),
183 /// Error E0403: the name is already used for a type or const parameter in this generic
185 NameAlreadyUsedInParameterList(Symbol, Span),
186 /// Error E0407: method is not a member of trait.
187 MethodNotMemberOfTrait(Symbol, &'a str),
188 /// Error E0437: type is not a member of trait.
189 TypeNotMemberOfTrait(Symbol, &'a str),
190 /// Error E0438: const is not a member of trait.
191 ConstNotMemberOfTrait(Symbol, &'a str),
192 /// Error E0408: variable `{}` is not bound in all patterns.
193 VariableNotBoundInPattern(&'a BindingError),
194 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
195 VariableBoundWithDifferentMode(Symbol, Span),
196 /// Error E0415: identifier is bound more than once in this parameter list.
197 IdentifierBoundMoreThanOnceInParameterList(Symbol),
198 /// Error E0416: identifier is bound more than once in the same pattern.
199 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
200 /// Error E0426: use of undeclared label.
201 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
202 /// Error E0429: `self` imports are only allowed within a `{ }` list.
203 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
204 /// Error E0430: `self` import can only appear once in the list.
205 SelfImportCanOnlyAppearOnceInTheList,
206 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
207 SelfImportOnlyInImportListWithNonEmptyPrefix,
208 /// Error E0433: failed to resolve.
209 FailedToResolve { label: String, suggestion: Option<Suggestion> },
210 /// Error E0434: can't capture dynamic environment in a fn item.
211 CannotCaptureDynamicEnvironmentInFnItem,
212 /// Error E0435: attempt to use a non-constant value in a constant.
213 AttemptToUseNonConstantValueInConstant(
215 /* suggestion */ &'static str,
216 /* current */ &'static str,
218 /// Error E0530: `X` bindings cannot shadow `Y`s.
219 BindingShadowsSomethingUnacceptable(&'static str, Symbol, &'a NameBinding<'a>),
220 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
221 ForwardDeclaredTyParam, // FIXME(const_generics_defaults)
222 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
223 ParamInTyOfConstParam(Symbol),
224 /// constant values inside of type parameter defaults must not depend on generic parameters.
225 ParamInAnonConstInTyDefault(Symbol),
226 /// generic parameters must not be used inside const evaluations.
228 /// This error is only emitted when using `min_const_generics`.
229 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
230 /// Error E0735: type parameters with a default cannot use `Self`
231 SelfInTyParamDefault,
232 /// Error E0767: use of unreachable label
233 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
236 enum VisResolutionError<'a> {
237 Relative2018(Span, &'a ast::Path),
239 FailedToResolve(Span, String, Option<Suggestion>),
240 ExpectedFound(Span, String, Res),
245 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
246 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
247 #[derive(Clone, Copy, Debug)]
251 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
252 /// nonsensical suggestions.
253 has_generic_args: bool,
257 fn from_path(path: &Path) -> Vec<Segment> {
258 path.segments.iter().map(|s| s.into()).collect()
261 fn from_ident(ident: Ident) -> Segment {
262 Segment { ident, id: None, has_generic_args: false }
265 fn names_to_string(segments: &[Segment]) -> String {
266 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
270 impl<'a> From<&'a ast::PathSegment> for Segment {
271 fn from(seg: &'a ast::PathSegment) -> Segment {
272 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
276 struct UsePlacementFinder {
277 target_module: NodeId,
282 impl UsePlacementFinder {
283 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
284 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
285 visit::walk_crate(&mut finder, krate);
286 (finder.span, finder.found_use)
290 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
293 module: &'tcx ast::Mod,
295 _: &[ast::Attribute],
298 if self.span.is_some() {
301 if node_id != self.target_module {
302 visit::walk_mod(self, module);
305 // find a use statement
306 for item in &module.items {
308 ItemKind::Use(..) => {
309 // don't suggest placing a use before the prelude
310 // import or other generated ones
311 if !item.span.from_expansion() {
312 self.span = Some(item.span.shrink_to_lo());
313 self.found_use = true;
317 // don't place use before extern crate
318 ItemKind::ExternCrate(_) => {}
319 // but place them before the first other item
321 if self.span.map_or(true, |span| item.span < span)
322 && !item.span.from_expansion()
324 // don't insert between attributes and an item
325 if item.attrs.is_empty() {
326 self.span = Some(item.span.shrink_to_lo());
328 // find the first attribute on the item
329 for attr in &item.attrs {
330 if self.span.map_or(true, |span| attr.span < span) {
331 self.span = Some(attr.span.shrink_to_lo());
342 /// An intermediate resolution result.
344 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
345 /// items are visible in their whole block, while `Res`es only from the place they are defined
348 enum LexicalScopeBinding<'a> {
349 Item(&'a NameBinding<'a>),
353 impl<'a> LexicalScopeBinding<'a> {
354 fn res(self) -> Res {
356 LexicalScopeBinding::Item(binding) => binding.res(),
357 LexicalScopeBinding::Res(res) => res,
362 #[derive(Copy, Clone, Debug)]
363 enum ModuleOrUniformRoot<'a> {
367 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
368 CrateRootAndExternPrelude,
370 /// Virtual module that denotes resolution in extern prelude.
371 /// Used for paths starting with `::` on 2018 edition.
374 /// Virtual module that denotes resolution in current scope.
375 /// Used only for resolving single-segment imports. The reason it exists is that import paths
376 /// are always split into two parts, the first of which should be some kind of module.
380 impl ModuleOrUniformRoot<'_> {
381 fn same_def(lhs: Self, rhs: Self) -> bool {
383 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
384 lhs.def_id() == rhs.def_id()
387 ModuleOrUniformRoot::CrateRootAndExternPrelude,
388 ModuleOrUniformRoot::CrateRootAndExternPrelude,
390 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
391 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
397 #[derive(Clone, Debug)]
398 enum PathResult<'a> {
399 Module(ModuleOrUniformRoot<'a>),
400 NonModule(PartialRes),
405 suggestion: Option<Suggestion>,
406 is_error_from_last_segment: bool,
412 /// An anonymous module; e.g., just a block.
417 /// { // This is an anonymous module
418 /// f(); // This resolves to (2) as we are inside the block.
421 /// f(); // Resolves to (1)
425 /// Any module with a name.
429 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
430 /// or the crate root (which is conceptually a top-level module).
431 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
432 /// * A trait or an enum (it implicitly contains associated types, methods and variant
434 Def(DefKind, DefId, Symbol),
438 /// Get name of the module.
439 pub fn name(&self) -> Option<Symbol> {
441 ModuleKind::Block(..) => None,
442 ModuleKind::Def(.., name) => Some(*name),
447 /// A key that identifies a binding in a given `Module`.
449 /// Multiple bindings in the same module can have the same key (in a valid
450 /// program) if all but one of them come from glob imports.
451 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
453 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
457 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
458 /// `_` in the expanded AST that introduced this binding.
462 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
464 /// One node in the tree of modules.
466 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
469 /// * crate root (aka, top-level anonymous module)
472 /// * curly-braced block with statements
474 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
475 pub struct ModuleData<'a> {
476 /// The direct parent module (it may not be a `mod`, however).
477 parent: Option<Module<'a>>,
478 /// What kind of module this is, because this may not be a `mod`.
481 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
482 /// This may be the crate root.
483 nearest_parent_mod: DefId,
485 /// Mapping between names and their (possibly in-progress) resolutions in this module.
486 /// Resolutions in modules from other crates are not populated until accessed.
487 lazy_resolutions: Resolutions<'a>,
488 /// True if this is a module from other crate that needs to be populated on access.
489 populate_on_access: Cell<bool>,
491 /// Macro invocations that can expand into items in this module.
492 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
494 /// Whether `#[no_implicit_prelude]` is active.
495 no_implicit_prelude: bool,
497 glob_importers: RefCell<Vec<&'a Import<'a>>>,
498 globs: RefCell<Vec<&'a Import<'a>>>,
500 /// Used to memoize the traits in this module for faster searches through all traits in scope.
501 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
503 /// Span of the module itself. Used for error reporting.
509 type Module<'a> = &'a ModuleData<'a>;
511 impl<'a> ModuleData<'a> {
513 parent: Option<Module<'a>>,
515 nearest_parent_mod: DefId,
523 lazy_resolutions: Default::default(),
524 populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
525 unexpanded_invocations: Default::default(),
526 no_implicit_prelude: false,
527 glob_importers: RefCell::new(Vec::new()),
528 globs: RefCell::new(Vec::new()),
529 traits: RefCell::new(None),
535 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
537 R: AsMut<Resolver<'a>>,
538 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
540 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
541 if let Some(binding) = name_resolution.borrow().binding {
542 f(resolver, key.ident, key.ns, binding);
547 /// This modifies `self` in place. The traits will be stored in `self.traits`.
548 fn ensure_traits<R>(&'a self, resolver: &mut R)
550 R: AsMut<Resolver<'a>>,
552 let mut traits = self.traits.borrow_mut();
553 if traits.is_none() {
554 let mut collected_traits = Vec::new();
555 self.for_each_child(resolver, |_, name, ns, binding| {
559 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
560 collected_traits.push((name, binding))
563 *traits = Some(collected_traits.into_boxed_slice());
567 fn res(&self) -> Option<Res> {
569 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
574 fn def_id(&self) -> Option<DefId> {
576 ModuleKind::Def(_, def_id, _) => Some(def_id),
581 // `self` resolves to the first module ancestor that `is_normal`.
582 fn is_normal(&self) -> bool {
583 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
586 fn is_trait(&self) -> bool {
587 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
590 fn nearest_item_scope(&'a self) -> Module<'a> {
592 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
593 self.parent.expect("enum or trait module without a parent")
599 fn is_ancestor_of(&self, mut other: &Self) -> bool {
600 while !ptr::eq(self, other) {
601 if let Some(parent) = other.parent {
611 impl<'a> fmt::Debug for ModuleData<'a> {
612 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
613 write!(f, "{:?}", self.res())
617 /// Records a possibly-private value, type, or module definition.
618 #[derive(Clone, Debug)]
619 pub struct NameBinding<'a> {
620 kind: NameBindingKind<'a>,
621 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
627 pub trait ToNameBinding<'a> {
628 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
631 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
632 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
637 #[derive(Clone, Debug)]
638 enum NameBindingKind<'a> {
639 Res(Res, /* is_macro_export */ bool),
641 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
644 impl<'a> NameBindingKind<'a> {
645 /// Is this a name binding of a import?
646 fn is_import(&self) -> bool {
647 matches!(*self, NameBindingKind::Import { .. })
651 struct PrivacyError<'a> {
653 binding: &'a NameBinding<'a>,
657 struct UseError<'a> {
658 err: DiagnosticBuilder<'a>,
659 /// Candidates which user could `use` to access the missing type.
660 candidates: Vec<ImportSuggestion>,
661 /// The `DefId` of the module to place the use-statements in.
663 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
665 /// Extra free-form suggestion.
666 suggestion: Option<(Span, &'static str, String, Applicability)>,
669 #[derive(Clone, Copy, PartialEq, Debug)]
674 MacroRulesVsModularized,
682 fn descr(self) -> &'static str {
684 AmbiguityKind::Import => "name vs any other name during import resolution",
685 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
686 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
687 AmbiguityKind::MacroRulesVsModularized => {
688 "`macro_rules` vs non-`macro_rules` from other module"
690 AmbiguityKind::GlobVsOuter => {
691 "glob import vs any other name from outer scope during import/macro resolution"
693 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
694 AmbiguityKind::GlobVsExpanded => {
695 "glob import vs macro-expanded name in the same \
696 module during import/macro resolution"
698 AmbiguityKind::MoreExpandedVsOuter => {
699 "macro-expanded name vs less macro-expanded name \
700 from outer scope during import/macro resolution"
706 /// Miscellaneous bits of metadata for better ambiguity error reporting.
707 #[derive(Clone, Copy, PartialEq)]
708 enum AmbiguityErrorMisc {
715 struct AmbiguityError<'a> {
718 b1: &'a NameBinding<'a>,
719 b2: &'a NameBinding<'a>,
720 misc1: AmbiguityErrorMisc,
721 misc2: AmbiguityErrorMisc,
724 impl<'a> NameBinding<'a> {
725 fn module(&self) -> Option<Module<'a>> {
727 NameBindingKind::Module(module) => Some(module),
728 NameBindingKind::Import { binding, .. } => binding.module(),
733 fn res(&self) -> Res {
735 NameBindingKind::Res(res, _) => res,
736 NameBindingKind::Module(module) => module.res().unwrap(),
737 NameBindingKind::Import { binding, .. } => binding.res(),
741 fn is_ambiguity(&self) -> bool {
742 self.ambiguity.is_some()
744 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
749 fn is_possibly_imported_variant(&self) -> bool {
751 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
752 _ => self.is_variant(),
756 // We sometimes need to treat variants as `pub` for backwards compatibility.
757 fn pseudo_vis(&self) -> ty::Visibility {
758 if self.is_variant() && self.res().def_id().is_local() {
759 ty::Visibility::Public
765 fn is_variant(&self) -> bool {
766 matches!(self.kind, NameBindingKind::Res(
767 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
772 fn is_extern_crate(&self) -> bool {
774 NameBindingKind::Import {
775 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
778 NameBindingKind::Module(&ModuleData {
779 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
781 }) => def_id.index == CRATE_DEF_INDEX,
786 fn is_import(&self) -> bool {
787 matches!(self.kind, NameBindingKind::Import { .. })
790 fn is_glob_import(&self) -> bool {
792 NameBindingKind::Import { import, .. } => import.is_glob(),
797 fn is_importable(&self) -> bool {
800 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
804 fn is_macro_def(&self) -> bool {
805 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
808 fn macro_kind(&self) -> Option<MacroKind> {
809 self.res().macro_kind()
812 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
813 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
814 // Then this function returns `true` if `self` may emerge from a macro *after* that
815 // in some later round and screw up our previously found resolution.
816 // See more detailed explanation in
817 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
818 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
819 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
820 // Expansions are partially ordered, so "may appear after" is an inversion of
821 // "certainly appears before or simultaneously" and includes unordered cases.
822 let self_parent_expansion = self.expansion;
823 let other_parent_expansion = binding.expansion;
824 let certainly_before_other_or_simultaneously =
825 other_parent_expansion.is_descendant_of(self_parent_expansion);
826 let certainly_before_invoc_or_simultaneously =
827 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
828 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
832 /// Interns the names of the primitive types.
834 /// All other types are defined somewhere and possibly imported, but the primitive ones need
835 /// special handling, since they have no place of origin.
836 struct PrimitiveTypeTable {
837 primitive_types: FxHashMap<Symbol, PrimTy>,
840 impl PrimitiveTypeTable {
841 fn new() -> PrimitiveTypeTable {
842 let mut table = FxHashMap::default();
844 table.insert(sym::bool, Bool);
845 table.insert(sym::char, Char);
846 table.insert(sym::f32, Float(FloatTy::F32));
847 table.insert(sym::f64, Float(FloatTy::F64));
848 table.insert(sym::isize, Int(IntTy::Isize));
849 table.insert(sym::i8, Int(IntTy::I8));
850 table.insert(sym::i16, Int(IntTy::I16));
851 table.insert(sym::i32, Int(IntTy::I32));
852 table.insert(sym::i64, Int(IntTy::I64));
853 table.insert(sym::i128, Int(IntTy::I128));
854 table.insert(sym::str, Str);
855 table.insert(sym::usize, Uint(UintTy::Usize));
856 table.insert(sym::u8, Uint(UintTy::U8));
857 table.insert(sym::u16, Uint(UintTy::U16));
858 table.insert(sym::u32, Uint(UintTy::U32));
859 table.insert(sym::u64, Uint(UintTy::U64));
860 table.insert(sym::u128, Uint(UintTy::U128));
861 Self { primitive_types: table }
865 #[derive(Debug, Default, Clone)]
866 pub struct ExternPreludeEntry<'a> {
867 extern_crate_item: Option<&'a NameBinding<'a>>,
868 pub introduced_by_item: bool,
871 /// Used for better errors for E0773
872 enum BuiltinMacroState {
873 NotYetSeen(SyntaxExtension),
877 /// The main resolver class.
879 /// This is the visitor that walks the whole crate.
880 pub struct Resolver<'a> {
881 session: &'a Session,
883 definitions: Definitions,
885 graph_root: Module<'a>,
887 prelude: Option<Module<'a>>,
888 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
890 /// N.B., this is used only for better diagnostics, not name resolution itself.
891 has_self: FxHashSet<DefId>,
893 /// Names of fields of an item `DefId` accessible with dot syntax.
894 /// Used for hints during error reporting.
895 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
897 /// All imports known to succeed or fail.
898 determined_imports: Vec<&'a Import<'a>>,
900 /// All non-determined imports.
901 indeterminate_imports: Vec<&'a Import<'a>>,
903 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
904 /// We are resolving a last import segment during import validation.
905 last_import_segment: bool,
906 /// This binding should be ignored during in-module resolution, so that we don't get
907 /// "self-confirming" import resolutions during import validation.
908 unusable_binding: Option<&'a NameBinding<'a>>,
910 /// The idents for the primitive types.
911 primitive_type_table: PrimitiveTypeTable,
913 /// Resolutions for nodes that have a single resolution.
914 partial_res_map: NodeMap<PartialRes>,
915 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
916 import_res_map: NodeMap<PerNS<Option<Res>>>,
917 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
918 label_res_map: NodeMap<NodeId>,
920 /// `CrateNum` resolutions of `extern crate` items.
921 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
922 export_map: ExportMap<LocalDefId>,
923 trait_map: NodeMap<Vec<TraitCandidate>>,
925 /// A map from nodes to anonymous modules.
926 /// Anonymous modules are pseudo-modules that are implicitly created around items
927 /// contained within blocks.
929 /// For example, if we have this:
937 /// There will be an anonymous module created around `g` with the ID of the
938 /// entry block for `f`.
939 block_map: NodeMap<Module<'a>>,
940 /// A fake module that contains no definition and no prelude. Used so that
941 /// some AST passes can generate identifiers that only resolve to local or
943 empty_module: Module<'a>,
944 module_map: FxHashMap<LocalDefId, Module<'a>>,
945 extern_module_map: FxHashMap<DefId, Module<'a>>,
946 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
947 underscore_disambiguator: u32,
949 /// Maps glob imports to the names of items actually imported.
950 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
951 /// Visibilities in "lowered" form, for all entities that have them.
952 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
953 used_imports: FxHashSet<(NodeId, Namespace)>,
954 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
955 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
957 /// Privacy errors are delayed until the end in order to deduplicate them.
958 privacy_errors: Vec<PrivacyError<'a>>,
959 /// Ambiguity errors are delayed for deduplication.
960 ambiguity_errors: Vec<AmbiguityError<'a>>,
961 /// `use` injections are delayed for better placement and deduplication.
962 use_injections: Vec<UseError<'a>>,
963 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
964 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
966 arenas: &'a ResolverArenas<'a>,
967 dummy_binding: &'a NameBinding<'a>,
969 crate_loader: CrateLoader<'a>,
970 macro_names: FxHashSet<Ident>,
971 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
972 registered_attrs: FxHashSet<Ident>,
973 registered_tools: FxHashSet<Ident>,
974 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
975 all_macros: FxHashMap<Symbol, Res>,
976 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
977 dummy_ext_bang: Lrc<SyntaxExtension>,
978 dummy_ext_derive: Lrc<SyntaxExtension>,
979 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
980 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
981 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
982 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
983 proc_macro_stubs: FxHashSet<LocalDefId>,
984 /// Traces collected during macro resolution and validated when it's complete.
985 single_segment_macro_resolutions:
986 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
987 multi_segment_macro_resolutions:
988 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
989 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
990 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
991 /// Derive macros cannot modify the item themselves and have to store the markers in the global
992 /// context, so they attach the markers to derive container IDs using this resolver table.
993 containers_deriving_copy: FxHashSet<ExpnId>,
994 /// Parent scopes in which the macros were invoked.
995 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
996 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
997 /// `macro_rules` scopes *produced* by expanding the macro invocations,
998 /// include all the `macro_rules` items and other invocations generated by them.
999 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScopeRef<'a>>,
1000 /// Helper attributes that are in scope for the given expansion.
1001 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
1003 /// Avoid duplicated errors for "name already defined".
1004 name_already_seen: FxHashMap<Symbol, Span>,
1006 potentially_unused_imports: Vec<&'a Import<'a>>,
1008 /// Table for mapping struct IDs into struct constructor IDs,
1009 /// it's not used during normal resolution, only for better error reporting.
1010 /// Also includes of list of each fields visibility
1011 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1013 /// Features enabled for this crate.
1014 active_features: FxHashSet<Symbol>,
1016 lint_buffer: LintBuffer,
1018 next_node_id: NodeId,
1020 def_id_to_span: IndexVec<LocalDefId, Span>,
1022 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1023 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1025 /// Indices of unnamed struct or variant fields with unresolved attributes.
1026 placeholder_field_indices: FxHashMap<NodeId, usize>,
1027 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1028 /// we know what parent node that fragment should be attached to thanks to this table.
1029 invocation_parents: FxHashMap<ExpnId, LocalDefId>,
1031 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1032 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1033 /// FIXME: Replace with a more general AST map (together with some other fields).
1034 trait_impl_items: FxHashSet<LocalDefId>,
1037 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1039 pub struct ResolverArenas<'a> {
1040 modules: TypedArena<ModuleData<'a>>,
1041 local_modules: RefCell<Vec<Module<'a>>>,
1042 imports: TypedArena<Import<'a>>,
1043 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1044 ast_paths: TypedArena<ast::Path>,
1045 dropless: DroplessArena,
1048 impl<'a> ResolverArenas<'a> {
1049 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1050 let module = self.modules.alloc(module);
1051 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1052 self.local_modules.borrow_mut().push(module);
1056 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1057 self.local_modules.borrow()
1059 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1060 self.dropless.alloc(name_binding)
1062 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1063 self.imports.alloc(import)
1065 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1066 self.name_resolutions.alloc(Default::default())
1068 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1069 PtrKey(self.dropless.alloc(Cell::new(scope)))
1071 fn alloc_macro_rules_binding(
1073 binding: MacroRulesBinding<'a>,
1074 ) -> &'a MacroRulesBinding<'a> {
1075 self.dropless.alloc(binding)
1077 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1078 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1080 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1081 self.dropless.alloc_from_iter(spans)
1085 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1086 fn as_mut(&mut self) -> &mut Resolver<'a> {
1091 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1092 fn parent(self, id: DefId) -> Option<DefId> {
1093 match id.as_local() {
1094 Some(id) => self.definitions.def_key(id).parent,
1095 None => self.cstore().def_key(id).parent,
1097 .map(|index| DefId { index, ..id })
1101 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1102 /// the resolver is no longer needed as all the relevant information is inline.
1103 impl ResolverAstLowering for Resolver<'_> {
1104 fn def_key(&mut self, id: DefId) -> DefKey {
1105 if let Some(id) = id.as_local() {
1106 self.definitions().def_key(id)
1108 self.cstore().def_key(id)
1112 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1113 self.cstore().item_generics_num_lifetimes(def_id, sess)
1116 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1117 self.partial_res_map.get(&id).cloned()
1120 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1121 self.import_res_map.get(&id).cloned().unwrap_or_default()
1124 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1125 self.label_res_map.get(&id).cloned()
1128 fn definitions(&mut self) -> &mut Definitions {
1129 &mut self.definitions
1132 fn lint_buffer(&mut self) -> &mut LintBuffer {
1133 &mut self.lint_buffer
1136 fn next_node_id(&mut self) -> NodeId {
1140 fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
1144 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1145 self.node_id_to_def_id.get(&node).copied()
1148 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1149 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1152 /// Adds a definition with a parent definition.
1156 node_id: ast::NodeId,
1162 !self.node_id_to_def_id.contains_key(&node_id),
1163 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1166 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1169 // Find the next free disambiguator for this key.
1170 let next_disambiguator = &mut self.next_disambiguator;
1171 let next_disambiguator = |parent, data| {
1172 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1173 let disambiguator = *next_disamb;
1174 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1178 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1180 assert_eq!(self.def_id_to_span.push(span), def_id);
1182 // Some things for which we allocate `LocalDefId`s don't correspond to
1183 // anything in the AST, so they don't have a `NodeId`. For these cases
1184 // we don't need a mapping from `NodeId` to `LocalDefId`.
1185 if node_id != ast::DUMMY_NODE_ID {
1186 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1187 self.node_id_to_def_id.insert(node_id, def_id);
1189 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1195 impl<'a> Resolver<'a> {
1197 session: &'a Session,
1200 metadata_loader: &'a MetadataLoaderDyn,
1201 arenas: &'a ResolverArenas<'a>,
1203 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1204 let root_def_id = root_local_def_id.to_def_id();
1205 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1206 let graph_root = arenas.alloc_module(ModuleData {
1207 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1208 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1210 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1211 let empty_module = arenas.alloc_module(ModuleData {
1212 no_implicit_prelude: true,
1221 let mut module_map = FxHashMap::default();
1222 module_map.insert(root_local_def_id, graph_root);
1224 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1225 let root = definitions.get_root_def();
1227 let mut visibilities = FxHashMap::default();
1228 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1230 let mut def_id_to_span = IndexVec::default();
1231 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1232 let mut def_id_to_node_id = IndexVec::default();
1233 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1234 let mut node_id_to_def_id = FxHashMap::default();
1235 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1237 let mut invocation_parents = FxHashMap::default();
1238 invocation_parents.insert(ExpnId::root(), root);
1240 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1244 .filter(|(_, entry)| entry.add_prelude)
1245 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1248 if !session.contains_name(&krate.attrs, sym::no_core) {
1249 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1250 if !session.contains_name(&krate.attrs, sym::no_std) {
1251 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1255 let (registered_attrs, registered_tools) =
1256 macros::registered_attrs_and_tools(session, &krate.attrs);
1258 let features = session.features_untracked();
1259 let non_macro_attr =
1260 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1262 let mut resolver = Resolver {
1267 // The outermost module has def ID 0; this is not reflected in the
1273 has_self: FxHashSet::default(),
1274 field_names: FxHashMap::default(),
1276 determined_imports: Vec::new(),
1277 indeterminate_imports: Vec::new(),
1279 last_import_segment: false,
1280 unusable_binding: None,
1282 primitive_type_table: PrimitiveTypeTable::new(),
1284 partial_res_map: Default::default(),
1285 import_res_map: Default::default(),
1286 label_res_map: Default::default(),
1287 extern_crate_map: Default::default(),
1288 export_map: FxHashMap::default(),
1289 trait_map: Default::default(),
1290 underscore_disambiguator: 0,
1293 block_map: Default::default(),
1294 extern_module_map: FxHashMap::default(),
1295 binding_parent_modules: FxHashMap::default(),
1296 ast_transform_scopes: FxHashMap::default(),
1298 glob_map: Default::default(),
1300 used_imports: FxHashSet::default(),
1301 maybe_unused_trait_imports: Default::default(),
1302 maybe_unused_extern_crates: Vec::new(),
1304 privacy_errors: Vec::new(),
1305 ambiguity_errors: Vec::new(),
1306 use_injections: Vec::new(),
1307 macro_expanded_macro_export_errors: BTreeSet::new(),
1310 dummy_binding: arenas.alloc_name_binding(NameBinding {
1311 kind: NameBindingKind::Res(Res::Err, false),
1313 expansion: ExpnId::root(),
1315 vis: ty::Visibility::Public,
1318 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1319 macro_names: FxHashSet::default(),
1320 builtin_macros: Default::default(),
1323 macro_use_prelude: FxHashMap::default(),
1324 all_macros: FxHashMap::default(),
1325 macro_map: FxHashMap::default(),
1326 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1327 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1328 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1329 invocation_parent_scopes: Default::default(),
1330 output_macro_rules_scopes: Default::default(),
1331 helper_attrs: Default::default(),
1332 local_macro_def_scopes: FxHashMap::default(),
1333 name_already_seen: FxHashMap::default(),
1334 potentially_unused_imports: Vec::new(),
1335 struct_constructors: Default::default(),
1336 unused_macros: Default::default(),
1337 proc_macro_stubs: Default::default(),
1338 single_segment_macro_resolutions: Default::default(),
1339 multi_segment_macro_resolutions: Default::default(),
1340 builtin_attrs: Default::default(),
1341 containers_deriving_copy: Default::default(),
1342 active_features: features
1343 .declared_lib_features
1345 .map(|(feat, ..)| *feat)
1346 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1348 lint_buffer: LintBuffer::default(),
1349 next_node_id: NodeId::from_u32(1),
1353 placeholder_field_indices: Default::default(),
1355 next_disambiguator: Default::default(),
1356 trait_impl_items: Default::default(),
1359 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1360 resolver.invocation_parent_scopes.insert(ExpnId::root(), root_parent_scope);
1365 pub fn next_node_id(&mut self) -> NodeId {
1370 .expect("input too large; ran out of NodeIds");
1371 self.next_node_id = ast::NodeId::from_usize(next);
1375 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1376 &mut self.lint_buffer
1379 pub fn arenas() -> ResolverArenas<'a> {
1383 pub fn into_outputs(self) -> ResolverOutputs {
1384 let definitions = self.definitions;
1385 let visibilities = self.visibilities;
1386 let extern_crate_map = self.extern_crate_map;
1387 let export_map = self.export_map;
1388 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1389 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1390 let glob_map = self.glob_map;
1393 cstore: Box::new(self.crate_loader.into_cstore()),
1398 maybe_unused_trait_imports,
1399 maybe_unused_extern_crates,
1400 extern_prelude: self
1403 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1408 pub fn clone_outputs(&self) -> ResolverOutputs {
1410 definitions: self.definitions.clone(),
1411 cstore: Box::new(self.cstore().clone()),
1412 visibilities: self.visibilities.clone(),
1413 extern_crate_map: self.extern_crate_map.clone(),
1414 export_map: self.export_map.clone(),
1415 glob_map: self.glob_map.clone(),
1416 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1417 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1418 extern_prelude: self
1421 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1426 pub fn cstore(&self) -> &CStore {
1427 self.crate_loader.cstore()
1430 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1431 self.non_macro_attrs[mark_used as usize].clone()
1434 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1436 MacroKind::Bang => self.dummy_ext_bang.clone(),
1437 MacroKind::Derive => self.dummy_ext_derive.clone(),
1438 MacroKind::Attr => self.non_macro_attr(true),
1442 /// Runs the function on each namespace.
1443 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1449 fn is_builtin_macro(&mut self, res: Res) -> bool {
1450 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1453 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1455 match ctxt.outer_expn().expn_data().macro_def_id {
1456 Some(def_id) => return def_id,
1457 None => ctxt.remove_mark(),
1462 /// Entry point to crate resolution.
1463 pub fn resolve_crate(&mut self, krate: &Crate) {
1464 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1466 ImportResolver { r: self }.finalize_imports();
1467 self.finalize_macro_resolutions();
1469 self.late_resolve_crate(krate);
1471 self.check_unused(krate);
1472 self.report_errors(krate);
1473 self.crate_loader.postprocess(krate);
1476 fn get_traits_in_module_containing_item(
1481 found_traits: &mut Vec<TraitCandidate>,
1482 parent_scope: &ParentScope<'a>,
1484 assert!(ns == TypeNS || ns == ValueNS);
1485 module.ensure_traits(self);
1486 let traits = module.traits.borrow();
1488 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
1489 // Traits have pseudo-modules that can be used to search for the given ident.
1490 if let Some(module) = binding.module() {
1491 let mut ident = ident;
1492 if ident.span.glob_adjust(module.expansion, binding.span).is_none() {
1496 .resolve_ident_in_module_unadjusted(
1497 ModuleOrUniformRoot::Module(module),
1506 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
1507 let trait_def_id = module.def_id().unwrap();
1508 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
1510 } else if let Res::Def(DefKind::TraitAlias, _) = binding.res() {
1511 // For now, just treat all trait aliases as possible candidates, since we don't
1512 // know if the ident is somewhere in the transitive bounds.
1513 let import_ids = self.find_transitive_imports(&binding.kind, trait_name);
1514 let trait_def_id = binding.res().def_id();
1515 found_traits.push(TraitCandidate { def_id: trait_def_id, import_ids });
1517 bug!("candidate is not trait or trait alias?")
1522 fn find_transitive_imports(
1524 mut kind: &NameBindingKind<'_>,
1526 ) -> SmallVec<[LocalDefId; 1]> {
1527 let mut import_ids = smallvec![];
1528 while let NameBindingKind::Import { import, binding, .. } = kind {
1529 let id = self.local_def_id(import.id);
1530 self.maybe_unused_trait_imports.insert(id);
1531 self.add_to_glob_map(&import, trait_name);
1532 import_ids.push(id);
1533 kind = &binding.kind;
1542 nearest_parent_mod: DefId,
1546 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1547 self.arenas.alloc_module(module)
1550 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1551 let ident = ident.normalize_to_macros_2_0();
1552 let disambiguator = if ident.name == kw::Underscore {
1553 self.underscore_disambiguator += 1;
1554 self.underscore_disambiguator
1558 BindingKey { ident, ns, disambiguator }
1561 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1562 if module.populate_on_access.get() {
1563 module.populate_on_access.set(false);
1564 self.build_reduced_graph_external(module);
1566 &module.lazy_resolutions
1573 ) -> &'a RefCell<NameResolution<'a>> {
1575 .resolutions(module)
1578 .or_insert_with(|| self.arenas.alloc_name_resolution())
1585 used_binding: &'a NameBinding<'a>,
1586 is_lexical_scope: bool,
1588 if let Some((b2, kind)) = used_binding.ambiguity {
1589 self.ambiguity_errors.push(AmbiguityError {
1594 misc1: AmbiguityErrorMisc::None,
1595 misc2: AmbiguityErrorMisc::None,
1598 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1599 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1600 // but not introduce it, as used if they are accessed from lexical scope.
1601 if is_lexical_scope {
1602 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1603 if let Some(crate_item) = entry.extern_crate_item {
1604 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1611 import.used.set(true);
1612 self.used_imports.insert((import.id, ns));
1613 self.add_to_glob_map(&import, ident);
1614 self.record_use(ident, ns, binding, false);
1619 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1620 if import.is_glob() {
1621 let def_id = self.local_def_id(import.id);
1622 self.glob_map.entry(def_id).or_default().insert(ident.name);
1626 /// A generic scope visitor.
1627 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1628 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1631 scope_set: ScopeSet,
1632 parent_scope: &ParentScope<'a>,
1634 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1636 // General principles:
1637 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1638 // built into the language or standard library. This way we can add new names into the
1639 // language or standard library without breaking user code.
1640 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1641 // Places to search (in order of decreasing priority):
1643 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1644 // (open set, not controlled).
1645 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1646 // (open, not controlled).
1647 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1648 // 4. Tool modules (closed, controlled right now, but not in the future).
1649 // 5. Standard library prelude (de-facto closed, controlled).
1650 // 6. Language prelude (closed, controlled).
1652 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1653 // (open set, not controlled).
1654 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1655 // (open, not controlled).
1656 // 3. Standard library prelude (de-facto closed, controlled).
1658 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1659 // are currently reported as errors. They should be higher in priority than preludes
1660 // and probably even names in modules according to the "general principles" above. They
1661 // also should be subject to restricted shadowing because are effectively produced by
1662 // derives (you need to resolve the derive first to add helpers into scope), but they
1663 // should be available before the derive is expanded for compatibility.
1664 // It's mess in general, so we are being conservative for now.
1665 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1666 // priority than prelude macros, but create ambiguities with macros in modules.
1667 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1668 // (open, not controlled). Have higher priority than prelude macros, but create
1669 // ambiguities with `macro_rules`.
1670 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1671 // 4a. User-defined prelude from macro-use
1672 // (open, the open part is from macro expansions, not controlled).
1673 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1674 // 4c. Standard library prelude (de-facto closed, controlled).
1675 // 6. Language prelude: builtin attributes (closed, controlled).
1677 let rust_2015 = ident.span.rust_2015();
1678 let (ns, macro_kind, is_absolute_path) = match scope_set {
1679 ScopeSet::All(ns, _) => (ns, None, false),
1680 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1681 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1683 // Jump out of trait or enum modules, they do not act as scopes.
1684 let module = parent_scope.module.nearest_item_scope();
1685 let mut scope = match ns {
1686 _ if is_absolute_path => Scope::CrateRoot,
1687 TypeNS | ValueNS => Scope::Module(module),
1688 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1690 let mut ident = ident.normalize_to_macros_2_0();
1691 let mut use_prelude = !module.no_implicit_prelude;
1694 let visit = match scope {
1695 // Derive helpers are not in scope when resolving derives in the same container.
1696 Scope::DeriveHelpers(expn_id) => {
1697 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1699 Scope::DeriveHelpersCompat => true,
1700 Scope::MacroRules(macro_rules_scope) => {
1701 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1702 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1703 // As another consequence of this optimization visitors never observe invocation
1704 // scopes for macros that were already expanded.
1705 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1706 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1707 macro_rules_scope.set(next_scope.get());
1714 Scope::CrateRoot => true,
1715 Scope::Module(..) => true,
1716 Scope::RegisteredAttrs => use_prelude,
1717 Scope::MacroUsePrelude => use_prelude || rust_2015,
1718 Scope::BuiltinAttrs => true,
1719 Scope::ExternPrelude => use_prelude || is_absolute_path,
1720 Scope::ToolPrelude => use_prelude,
1721 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1722 Scope::BuiltinTypes => true,
1726 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1727 return break_result;
1731 scope = match scope {
1732 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1733 // Derive helpers are not visible to code generated by bang or derive macros.
1734 let expn_data = expn_id.expn_data();
1735 match expn_data.kind {
1737 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1738 Scope::DeriveHelpersCompat
1740 _ => Scope::DeriveHelpers(expn_data.parent),
1743 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1744 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1745 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1746 MacroRulesScope::Binding(binding) => {
1747 Scope::MacroRules(binding.parent_macro_rules_scope)
1749 MacroRulesScope::Invocation(invoc_id) => {
1750 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1752 MacroRulesScope::Empty => Scope::Module(module),
1754 Scope::CrateRoot => match ns {
1756 ident.span.adjust(ExpnId::root());
1757 Scope::ExternPrelude
1759 ValueNS | MacroNS => break,
1761 Scope::Module(module) => {
1762 use_prelude = !module.no_implicit_prelude;
1763 match self.hygienic_lexical_parent(module, &mut ident.span) {
1764 Some(parent_module) => Scope::Module(parent_module),
1766 ident.span.adjust(ExpnId::root());
1768 TypeNS => Scope::ExternPrelude,
1769 ValueNS => Scope::StdLibPrelude,
1770 MacroNS => Scope::RegisteredAttrs,
1775 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1776 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1777 Scope::BuiltinAttrs => break, // nowhere else to search
1778 Scope::ExternPrelude if is_absolute_path => break,
1779 Scope::ExternPrelude => Scope::ToolPrelude,
1780 Scope::ToolPrelude => Scope::StdLibPrelude,
1781 Scope::StdLibPrelude => match ns {
1782 TypeNS => Scope::BuiltinTypes,
1783 ValueNS => break, // nowhere else to search
1784 MacroNS => Scope::BuiltinAttrs,
1786 Scope::BuiltinTypes => break, // nowhere else to search
1793 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1794 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1795 /// `ident` in the first scope that defines it (or None if no scopes define it).
1797 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1798 /// the items are defined in the block. For example,
1801 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1804 /// g(); // This resolves to the local variable `g` since it shadows the item.
1808 /// Invariant: This must only be called during main resolution, not during
1809 /// import resolution.
1810 fn resolve_ident_in_lexical_scope(
1814 parent_scope: &ParentScope<'a>,
1815 record_used_id: Option<NodeId>,
1818 ) -> Option<LexicalScopeBinding<'a>> {
1819 assert!(ns == TypeNS || ns == ValueNS);
1820 if ident.name == kw::Empty {
1821 return Some(LexicalScopeBinding::Res(Res::Err));
1823 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1824 // FIXME(jseyfried) improve `Self` hygiene
1825 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1826 (empty_span, empty_span)
1827 } else if ns == TypeNS {
1828 let normalized_span = ident.span.normalize_to_macros_2_0();
1829 (normalized_span, normalized_span)
1831 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1833 ident.span = general_span;
1834 let normalized_ident = Ident { span: normalized_span, ..ident };
1836 // Walk backwards up the ribs in scope.
1837 let record_used = record_used_id.is_some();
1838 let mut module = self.graph_root;
1839 for i in (0..ribs.len()).rev() {
1840 debug!("walk rib\n{:?}", ribs[i].bindings);
1841 // Use the rib kind to determine whether we are resolving parameters
1842 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1843 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1844 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1846 // The ident resolves to a type parameter or local variable.
1847 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1853 *original_rib_ident_def,
1858 module = match ribs[i].kind {
1859 ModuleRibKind(module) => module,
1860 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1861 // If an invocation of this macro created `ident`, give up on `ident`
1862 // and switch to `ident`'s source from the macro definition.
1863 ident.span.remove_mark();
1869 let item = self.resolve_ident_in_module_unadjusted(
1870 ModuleOrUniformRoot::Module(module),
1877 if let Ok(binding) = item {
1878 // The ident resolves to an item.
1879 return Some(LexicalScopeBinding::Item(binding));
1883 ModuleKind::Block(..) => {} // We can see through blocks
1888 ident = normalized_ident;
1889 let mut poisoned = None;
1891 let opt_module = if let Some(node_id) = record_used_id {
1892 self.hygienic_lexical_parent_with_compatibility_fallback(
1899 self.hygienic_lexical_parent(module, &mut ident.span)
1901 module = unwrap_or!(opt_module, break);
1902 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1903 let result = self.resolve_ident_in_module_unadjusted(
1904 ModuleOrUniformRoot::Module(module),
1907 adjusted_parent_scope,
1914 if let Some(node_id) = poisoned {
1915 self.lint_buffer.buffer_lint_with_diagnostic(
1916 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1919 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1920 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1923 return Some(LexicalScopeBinding::Item(binding));
1925 Err(Determined) => continue,
1926 Err(Undetermined) => {
1927 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1932 if !module.no_implicit_prelude {
1933 ident.span.adjust(ExpnId::root());
1935 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1936 return Some(LexicalScopeBinding::Item(binding));
1938 if let Some(ident) = self.registered_tools.get(&ident) {
1940 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1941 .to_name_binding(self.arenas);
1942 return Some(LexicalScopeBinding::Item(binding));
1945 if let Some(prelude) = self.prelude {
1946 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1947 ModuleOrUniformRoot::Module(prelude),
1954 return Some(LexicalScopeBinding::Item(binding));
1960 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1962 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1963 .to_name_binding(self.arenas);
1964 return Some(LexicalScopeBinding::Item(binding));
1971 fn hygienic_lexical_parent(
1975 ) -> Option<Module<'a>> {
1976 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1977 return Some(self.macro_def_scope(span.remove_mark()));
1980 if let ModuleKind::Block(..) = module.kind {
1981 return Some(module.parent.unwrap().nearest_item_scope());
1987 fn hygienic_lexical_parent_with_compatibility_fallback(
1992 poisoned: &mut Option<NodeId>,
1993 ) -> Option<Module<'a>> {
1994 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1998 // We need to support the next case under a deprecation warning
2001 // ---- begin: this comes from a proc macro derive
2002 // mod implementation_details {
2003 // // Note that `MyStruct` is not in scope here.
2004 // impl SomeTrait for MyStruct { ... }
2008 // So we have to fall back to the module's parent during lexical resolution in this case.
2009 if let Some(parent) = module.parent {
2010 // Inner module is inside the macro, parent module is outside of the macro.
2011 if module.expansion != parent.expansion
2012 && module.expansion.is_descendant_of(parent.expansion)
2014 // The macro is a proc macro derive
2015 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2016 let ext = self.get_macro_by_def_id(def_id);
2017 if ext.builtin_name.is_none()
2018 && ext.macro_kind() == MacroKind::Derive
2019 && parent.expansion.outer_expn_is_descendant_of(span.ctxt())
2021 *poisoned = Some(node_id);
2022 return module.parent;
2031 fn resolve_ident_in_module(
2033 module: ModuleOrUniformRoot<'a>,
2036 parent_scope: &ParentScope<'a>,
2039 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2040 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2041 .map_err(|(determinacy, _)| determinacy)
2044 fn resolve_ident_in_module_ext(
2046 module: ModuleOrUniformRoot<'a>,
2049 parent_scope: &ParentScope<'a>,
2052 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2053 let tmp_parent_scope;
2054 let mut adjusted_parent_scope = parent_scope;
2056 ModuleOrUniformRoot::Module(m) => {
2057 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2059 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2060 adjusted_parent_scope = &tmp_parent_scope;
2063 ModuleOrUniformRoot::ExternPrelude => {
2064 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2066 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2070 self.resolve_ident_in_module_unadjusted_ext(
2074 adjusted_parent_scope,
2081 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2082 debug!("resolve_crate_root({:?})", ident);
2083 let mut ctxt = ident.span.ctxt();
2084 let mark = if ident.name == kw::DollarCrate {
2085 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2086 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2087 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2088 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2089 // definitions actually produced by `macro` and `macro` definitions produced by
2090 // `macro_rules!`, but at least such configurations are not stable yet.
2091 ctxt = ctxt.normalize_to_macro_rules();
2093 "resolve_crate_root: marks={:?}",
2094 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2096 let mut iter = ctxt.marks().into_iter().rev().peekable();
2097 let mut result = None;
2098 // Find the last opaque mark from the end if it exists.
2099 while let Some(&(mark, transparency)) = iter.peek() {
2100 if transparency == Transparency::Opaque {
2101 result = Some(mark);
2108 "resolve_crate_root: found opaque mark {:?} {:?}",
2110 result.map(|r| r.expn_data())
2112 // Then find the last semi-transparent mark from the end if it exists.
2113 for (mark, transparency) in iter {
2114 if transparency == Transparency::SemiTransparent {
2115 result = Some(mark);
2121 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2123 result.map(|r| r.expn_data())
2127 debug!("resolve_crate_root: not DollarCrate");
2128 ctxt = ctxt.normalize_to_macros_2_0();
2129 ctxt.adjust(ExpnId::root())
2131 let module = match mark {
2132 Some(def) => self.macro_def_scope(def),
2135 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2138 return self.graph_root;
2141 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2143 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2152 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2153 let mut module = self.get_module(module.nearest_parent_mod);
2154 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2155 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2156 module = self.get_module(parent.nearest_parent_mod);
2164 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2165 parent_scope: &ParentScope<'a>,
2168 crate_lint: CrateLint,
2169 ) -> PathResult<'a> {
2170 self.resolve_path_with_ribs(
2181 fn resolve_path_with_ribs(
2184 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2185 parent_scope: &ParentScope<'a>,
2188 crate_lint: CrateLint,
2189 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2190 ) -> PathResult<'a> {
2191 let mut module = None;
2192 let mut allow_super = true;
2193 let mut second_binding = None;
2196 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2197 path_span={:?}, crate_lint={:?})",
2198 path, opt_ns, record_used, path_span, crate_lint,
2201 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2202 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2203 let record_segment_res = |this: &mut Self, res| {
2205 if let Some(id) = id {
2206 if !this.partial_res_map.contains_key(&id) {
2207 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2208 this.record_partial_res(id, PartialRes::new(res));
2214 let is_last = i == path.len() - 1;
2215 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2216 let name = ident.name;
2218 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2221 if allow_super && name == kw::Super {
2222 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2223 let self_module = match i {
2224 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2226 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2230 if let Some(self_module) = self_module {
2231 if let Some(parent) = self_module.parent {
2232 module = Some(ModuleOrUniformRoot::Module(
2233 self.resolve_self(&mut ctxt, parent),
2238 let msg = "there are too many leading `super` keywords".to_string();
2239 return PathResult::Failed {
2243 is_error_from_last_segment: false,
2247 if name == kw::SelfLower {
2248 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2249 module = Some(ModuleOrUniformRoot::Module(
2250 self.resolve_self(&mut ctxt, parent_scope.module),
2254 if name == kw::PathRoot && ident.span.rust_2018() {
2255 module = Some(ModuleOrUniformRoot::ExternPrelude);
2258 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2259 // `::a::b` from 2015 macro on 2018 global edition
2260 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2263 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2264 // `::a::b`, `crate::a::b` or `$crate::a::b`
2265 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2271 // Report special messages for path segment keywords in wrong positions.
2272 if ident.is_path_segment_keyword() && i != 0 {
2273 let name_str = if name == kw::PathRoot {
2274 "crate root".to_string()
2276 format!("`{}`", name)
2278 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2279 format!("global paths cannot start with {}", name_str)
2281 format!("{} in paths can only be used in start position", name_str)
2283 return PathResult::Failed {
2287 is_error_from_last_segment: false,
2291 enum FindBindingResult<'a> {
2292 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2293 PathResult(PathResult<'a>),
2295 let find_binding_in_ns = |this: &mut Self, ns| {
2296 let binding = if let Some(module) = module {
2297 this.resolve_ident_in_module(
2305 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2306 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2307 this.early_resolve_ident_in_lexical_scope(
2316 let record_used_id = if record_used {
2317 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2321 match this.resolve_ident_in_lexical_scope(
2329 // we found a locally-imported or available item/module
2330 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2331 // we found a local variable or type param
2332 Some(LexicalScopeBinding::Res(res))
2333 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2335 record_segment_res(this, res);
2336 return FindBindingResult::PathResult(PathResult::NonModule(
2337 PartialRes::with_unresolved_segments(res, path.len() - 1),
2340 _ => Err(Determinacy::determined(record_used)),
2343 FindBindingResult::Binding(binding)
2345 let binding = match find_binding_in_ns(self, ns) {
2346 FindBindingResult::PathResult(x) => return x,
2347 FindBindingResult::Binding(binding) => binding,
2352 second_binding = Some(binding);
2354 let res = binding.res();
2355 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2356 if let Some(next_module) = binding.module() {
2357 module = Some(ModuleOrUniformRoot::Module(next_module));
2358 record_segment_res(self, res);
2359 } else if res == Res::ToolMod && i + 1 != path.len() {
2360 if binding.is_import() {
2364 "cannot use a tool module through an import",
2366 .span_note(binding.span, "the tool module imported here")
2369 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2370 return PathResult::NonModule(PartialRes::new(res));
2371 } else if res == Res::Err {
2372 return PathResult::NonModule(PartialRes::new(Res::Err));
2373 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2374 self.lint_if_path_starts_with_module(
2380 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2385 let label = format!(
2386 "`{}` is {} {}, not a module",
2392 return PathResult::Failed {
2396 is_error_from_last_segment: is_last,
2400 Err(Undetermined) => return PathResult::Indeterminate,
2401 Err(Determined) => {
2402 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2403 if opt_ns.is_some() && !module.is_normal() {
2404 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2405 module.res().unwrap(),
2410 let module_res = match module {
2411 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2414 let (label, suggestion) = if module_res == self.graph_root.res() {
2415 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2416 // Don't look up import candidates if this is a speculative resolve
2417 let mut candidates = if record_used {
2418 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2422 candidates.sort_by_cached_key(|c| {
2423 (c.path.segments.len(), pprust::path_to_string(&c.path))
2425 if let Some(candidate) = candidates.get(0) {
2427 String::from("unresolved import"),
2429 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2430 String::from("a similar path exists"),
2431 Applicability::MaybeIncorrect,
2435 (format!("maybe a missing crate `{}`?", ident), None)
2443 .map_or(false, |c| c.is_ascii_uppercase())
2445 (format!("use of undeclared type `{}`", ident), None)
2447 (format!("use of undeclared crate or module `{}`", ident), None)
2451 format!("could not find `{}` in `{}`", ident, path[i - 1].ident);
2452 if ns == TypeNS || ns == ValueNS {
2453 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2454 if let FindBindingResult::Binding(Ok(binding)) =
2455 find_binding_in_ns(self, ns_to_try)
2457 let mut found = |what| {
2459 "expected {}, found {} `{}` in `{}`",
2466 if binding.module().is_some() {
2469 match binding.res() {
2470 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2471 _ => found(ns_to_try.descr()),
2478 return PathResult::Failed {
2482 is_error_from_last_segment: is_last,
2488 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2490 PathResult::Module(match module {
2491 Some(module) => module,
2492 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2493 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2497 fn lint_if_path_starts_with_module(
2499 crate_lint: CrateLint,
2502 second_binding: Option<&NameBinding<'_>>,
2504 let (diag_id, diag_span) = match crate_lint {
2505 CrateLint::No => return,
2506 CrateLint::SimplePath(id) => (id, path_span),
2507 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2508 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2511 let first_name = match path.get(0) {
2512 // In the 2018 edition this lint is a hard error, so nothing to do
2513 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2517 // We're only interested in `use` paths which should start with
2518 // `{{root}}` currently.
2519 if first_name != kw::PathRoot {
2524 // If this import looks like `crate::...` it's already good
2525 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2526 // Otherwise go below to see if it's an extern crate
2528 // If the path has length one (and it's `PathRoot` most likely)
2529 // then we don't know whether we're gonna be importing a crate or an
2530 // item in our crate. Defer this lint to elsewhere
2534 // If the first element of our path was actually resolved to an
2535 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2536 // warning, this looks all good!
2537 if let Some(binding) = second_binding {
2538 if let NameBindingKind::Import { import, .. } = binding.kind {
2539 // Careful: we still want to rewrite paths from renamed extern crates.
2540 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2546 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2547 self.lint_buffer.buffer_lint_with_diagnostic(
2548 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2551 "absolute paths must start with `self`, `super`, \
2552 `crate`, or an external crate name in the 2018 edition",
2557 // Validate a local resolution (from ribs).
2558 fn validate_res_from_ribs(
2565 original_rib_ident_def: Ident,
2566 all_ribs: &[Rib<'a>],
2568 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2569 debug!("validate_res_from_ribs({:?})", res);
2570 let ribs = &all_ribs[rib_index + 1..];
2572 // An invalid forward use of a type parameter from a previous default.
2573 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2575 let res_error = if rib_ident.name == kw::SelfUpper {
2576 ResolutionError::SelfInTyParamDefault
2578 ResolutionError::ForwardDeclaredTyParam
2580 self.report_error(span, res_error);
2582 assert_eq!(res, Res::Err);
2588 use ResolutionError::*;
2589 let mut res_err = None;
2594 | ClosureOrAsyncRibKind
2596 | MacroDefinition(..)
2597 | ForwardTyParamBanRibKind => {
2598 // Nothing to do. Continue.
2600 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2601 // This was an attempt to access an upvar inside a
2602 // named function item. This is not allowed, so we
2605 // We don't immediately trigger a resolve error, because
2606 // we want certain other resolution errors (namely those
2607 // emitted for `ConstantItemRibKind` below) to take
2609 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2612 ConstantItemRibKind(_, item) => {
2613 // Still doesn't deal with upvars
2615 let (span, resolution_error) =
2616 if let Some((ident, constant_item_kind)) = item {
2617 let kind_str = match constant_item_kind {
2618 ConstantItemKind::Const => "const",
2619 ConstantItemKind::Static => "static",
2623 AttemptToUseNonConstantValueInConstant(
2624 ident, "let", kind_str,
2630 AttemptToUseNonConstantValueInConstant(
2631 original_rib_ident_def,
2637 self.report_error(span, resolution_error);
2641 ConstParamTyRibKind => {
2643 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2649 if let Some(res_err) = res_err {
2650 self.report_error(span, res_err);
2654 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2655 let mut in_ty_param_default = false;
2657 let has_generic_params = match rib.kind {
2659 | ClosureOrAsyncRibKind
2662 | MacroDefinition(..) => {
2663 // Nothing to do. Continue.
2667 // We only forbid constant items if we are inside of type defaults,
2668 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2669 ForwardTyParamBanRibKind => {
2670 in_ty_param_default = true;
2673 ConstantItemRibKind(trivial, _) => {
2674 let features = self.session.features_untracked();
2675 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2677 || features.const_generics
2678 || features.lazy_normalization_consts)
2680 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2681 // we can't easily tell if it's generic at this stage, so we instead remember
2682 // this and then enforce the self type to be concrete later on.
2683 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2684 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2689 ResolutionError::ParamInNonTrivialAnonConst {
2690 name: rib_ident.name,
2696 self.session.delay_span_bug(span, CG_BUG_STR);
2701 if in_ty_param_default {
2705 ResolutionError::ParamInAnonConstInTyDefault(
2716 // This was an attempt to use a type parameter outside its scope.
2717 ItemRibKind(has_generic_params) => has_generic_params,
2718 FnItemRibKind => HasGenericParams::Yes,
2719 ConstParamTyRibKind => {
2723 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2733 ResolutionError::GenericParamsFromOuterFunction(
2742 Res::Def(DefKind::ConstParam, _) => {
2743 let mut ribs = ribs.iter().peekable();
2744 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2745 // When declaring const parameters inside function signatures, the first rib
2746 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2747 // (spuriously) conflicting with the const param.
2751 let mut in_ty_param_default = false;
2753 let has_generic_params = match rib.kind {
2755 | ClosureOrAsyncRibKind
2758 | MacroDefinition(..) => continue,
2760 // We only forbid constant items if we are inside of type defaults,
2761 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2762 ForwardTyParamBanRibKind => {
2763 in_ty_param_default = true;
2766 ConstantItemRibKind(trivial, _) => {
2767 let features = self.session.features_untracked();
2768 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2770 || features.const_generics
2771 || features.lazy_normalization_consts)
2776 ResolutionError::ParamInNonTrivialAnonConst {
2777 name: rib_ident.name,
2783 self.session.delay_span_bug(span, CG_BUG_STR);
2787 if in_ty_param_default {
2791 ResolutionError::ParamInAnonConstInTyDefault(
2802 ItemRibKind(has_generic_params) => has_generic_params,
2803 FnItemRibKind => HasGenericParams::Yes,
2804 ConstParamTyRibKind => {
2808 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2815 // This was an attempt to use a const parameter outside its scope.
2819 ResolutionError::GenericParamsFromOuterFunction(
2833 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2834 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2835 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2836 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2840 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2841 vis.is_accessible_from(module.nearest_parent_mod, self)
2844 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2845 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2846 if !ptr::eq(module, old_module) {
2847 span_bug!(binding.span, "parent module is reset for binding");
2852 fn disambiguate_macro_rules_vs_modularized(
2854 macro_rules: &'a NameBinding<'a>,
2855 modularized: &'a NameBinding<'a>,
2857 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2858 // is disambiguated to mitigate regressions from macro modularization.
2859 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2861 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2862 self.binding_parent_modules.get(&PtrKey(modularized)),
2864 (Some(macro_rules), Some(modularized)) => {
2865 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2866 && modularized.is_ancestor_of(macro_rules)
2872 fn report_errors(&mut self, krate: &Crate) {
2873 self.report_with_use_injections(krate);
2875 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2876 let msg = "macro-expanded `macro_export` macros from the current crate \
2877 cannot be referred to by absolute paths";
2878 self.lint_buffer.buffer_lint_with_diagnostic(
2879 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2883 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2887 for ambiguity_error in &self.ambiguity_errors {
2888 self.report_ambiguity_error(ambiguity_error);
2891 let mut reported_spans = FxHashSet::default();
2892 for error in &self.privacy_errors {
2893 if reported_spans.insert(error.dedup_span) {
2894 self.report_privacy_error(error);
2899 fn report_with_use_injections(&mut self, krate: &Crate) {
2900 for UseError { mut err, candidates, def_id, instead, suggestion } in
2901 self.use_injections.drain(..)
2903 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2904 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2908 if !candidates.is_empty() {
2909 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2910 } else if let Some((span, msg, sugg, appl)) = suggestion {
2911 err.span_suggestion(span, msg, sugg, appl);
2917 fn report_conflict<'b>(
2922 new_binding: &NameBinding<'b>,
2923 old_binding: &NameBinding<'b>,
2925 // Error on the second of two conflicting names
2926 if old_binding.span.lo() > new_binding.span.lo() {
2927 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2930 let container = match parent.kind {
2931 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2932 ModuleKind::Block(..) => "block",
2935 let old_noun = match old_binding.is_import() {
2937 false => "definition",
2940 let new_participle = match new_binding.is_import() {
2946 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2948 if let Some(s) = self.name_already_seen.get(&name) {
2954 let old_kind = match (ns, old_binding.module()) {
2955 (ValueNS, _) => "value",
2956 (MacroNS, _) => "macro",
2957 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2958 (TypeNS, Some(module)) if module.is_normal() => "module",
2959 (TypeNS, Some(module)) if module.is_trait() => "trait",
2960 (TypeNS, _) => "type",
2963 let msg = format!("the name `{}` is defined multiple times", name);
2965 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2966 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2967 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2968 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2969 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2971 _ => match (old_binding.is_import(), new_binding.is_import()) {
2972 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2973 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2974 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2979 "`{}` must be defined only once in the {} namespace of this {}",
2985 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2987 self.session.source_map().guess_head_span(old_binding.span),
2988 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2991 // See https://github.com/rust-lang/rust/issues/32354
2992 use NameBindingKind::Import;
2993 let import = match (&new_binding.kind, &old_binding.kind) {
2994 // If there are two imports where one or both have attributes then prefer removing the
2995 // import without attributes.
2996 (Import { import: new, .. }, Import { import: old, .. })
2998 !new_binding.span.is_dummy()
2999 && !old_binding.span.is_dummy()
3000 && (new.has_attributes || old.has_attributes)
3003 if old.has_attributes {
3004 Some((new, new_binding.span, true))
3006 Some((old, old_binding.span, true))
3009 // Otherwise prioritize the new binding.
3010 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3011 Some((import, new_binding.span, other.is_import()))
3013 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3014 Some((import, old_binding.span, other.is_import()))
3019 // Check if the target of the use for both bindings is the same.
3020 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3021 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3023 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
3024 // Only suggest removing an import if both bindings are to the same def, if both spans
3025 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3026 // been introduced by a item.
3027 let should_remove_import = duplicate
3029 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3032 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3033 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3035 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3036 // Simple case - remove the entire import. Due to the above match arm, this can
3037 // only be a single use so just remove it entirely.
3038 err.tool_only_span_suggestion(
3039 import.use_span_with_attributes,
3040 "remove unnecessary import",
3042 Applicability::MaybeIncorrect,
3045 Some((import, span, _)) => {
3046 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3052 self.name_already_seen.insert(name, span);
3055 /// This function adds a suggestion to change the binding name of a new import that conflicts
3056 /// with an existing import.
3058 /// ```text,ignore (diagnostic)
3059 /// help: you can use `as` to change the binding name of the import
3061 /// LL | use foo::bar as other_bar;
3062 /// | ^^^^^^^^^^^^^^^^^^^^^
3064 fn add_suggestion_for_rename_of_use(
3066 err: &mut DiagnosticBuilder<'_>,
3068 import: &Import<'_>,
3071 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3072 format!("Other{}", name)
3074 format!("other_{}", name)
3077 let mut suggestion = None;
3079 ImportKind::Single { type_ns_only: true, .. } => {
3080 suggestion = Some(format!("self as {}", suggested_name))
3082 ImportKind::Single { source, .. } => {
3084 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3086 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3087 if pos <= snippet.len() {
3088 suggestion = Some(format!(
3092 if snippet.ends_with(';') { ";" } else { "" }
3098 ImportKind::ExternCrate { source, target, .. } => {
3099 suggestion = Some(format!(
3100 "extern crate {} as {};",
3101 source.unwrap_or(target.name),
3105 _ => unreachable!(),
3108 let rename_msg = "you can use `as` to change the binding name of the import";
3109 if let Some(suggestion) = suggestion {
3110 err.span_suggestion(
3114 Applicability::MaybeIncorrect,
3117 err.span_label(binding_span, rename_msg);
3121 /// This function adds a suggestion to remove a unnecessary binding from an import that is
3122 /// nested. In the following example, this function will be invoked to remove the `a` binding
3123 /// in the second use statement:
3125 /// ```ignore (diagnostic)
3126 /// use issue_52891::a;
3127 /// use issue_52891::{d, a, e};
3130 /// The following suggestion will be added:
3132 /// ```ignore (diagnostic)
3133 /// use issue_52891::{d, a, e};
3134 /// ^-- help: remove unnecessary import
3137 /// If the nested use contains only one import then the suggestion will remove the entire
3140 /// It is expected that the provided import is nested - this isn't checked by the
3141 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3142 /// as characters expected by span manipulations won't be present.
3143 fn add_suggestion_for_duplicate_nested_use(
3145 err: &mut DiagnosticBuilder<'_>,
3146 import: &Import<'_>,
3149 assert!(import.is_nested());
3150 let message = "remove unnecessary import";
3152 // Two examples will be used to illustrate the span manipulations we're doing:
3154 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3155 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3156 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3157 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3159 let (found_closing_brace, span) =
3160 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3162 // If there was a closing brace then identify the span to remove any trailing commas from
3163 // previous imports.
3164 if found_closing_brace {
3165 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3166 err.tool_only_span_suggestion(
3170 Applicability::MaybeIncorrect,
3173 // Remove the entire line if we cannot extend the span back, this indicates a
3174 // `issue_52891::{self}` case.
3175 err.span_suggestion(
3176 import.use_span_with_attributes,
3179 Applicability::MaybeIncorrect,
3186 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3189 fn extern_prelude_get(
3193 ) -> Option<&'a NameBinding<'a>> {
3194 if ident.is_path_segment_keyword() {
3195 // Make sure `self`, `super` etc produce an error when passed to here.
3198 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3199 if let Some(binding) = entry.extern_crate_item {
3200 if !speculative && entry.introduced_by_item {
3201 self.record_use(ident, TypeNS, binding, false);
3205 let crate_id = if !speculative {
3206 self.crate_loader.process_path_extern(ident.name, ident.span)
3208 self.crate_loader.maybe_process_path_extern(ident.name)?
3210 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3212 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3213 .to_name_binding(self.arenas),
3219 /// This is equivalent to `get_traits_in_module_containing_item`, but without filtering by the associated item.
3221 /// This is used by rustdoc for intra-doc links.
3222 pub fn traits_in_scope(&mut self, module_id: DefId) -> Vec<TraitCandidate> {
3223 let module = self.get_module(module_id);
3224 module.ensure_traits(self);
3225 let traits = module.traits.borrow();
3227 |this: &mut Self, &(trait_name, binding): &(Ident, &NameBinding<'_>)| TraitCandidate {
3228 def_id: binding.res().def_id(),
3229 import_ids: this.find_transitive_imports(&binding.kind, trait_name),
3232 let mut candidates: Vec<_> =
3233 traits.as_ref().unwrap().iter().map(|x| to_candidate(self, x)).collect();
3235 if let Some(prelude) = self.prelude {
3236 if !module.no_implicit_prelude {
3237 prelude.ensure_traits(self);
3239 prelude.traits.borrow().as_ref().unwrap().iter().map(|x| to_candidate(self, x)),
3247 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3248 /// isn't something that can be returned because it can't be made to live that long,
3249 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3250 /// just that an error occurred.
3251 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3252 pub fn resolve_str_path_error(
3258 ) -> Result<(ast::Path, Res), ()> {
3259 let path = if path_str.starts_with("::") {
3262 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3263 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3264 .map(|i| self.new_ast_path_segment(i))
3273 .map(Ident::from_str)
3274 .map(|i| self.new_ast_path_segment(i))
3279 let module = self.get_module(module_id);
3280 let parent_scope = &ParentScope::module(module, self);
3281 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3285 // Resolve a path passed from rustdoc or HIR lowering.
3286 fn resolve_ast_path(
3290 parent_scope: &ParentScope<'a>,
3291 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3292 match self.resolve_path(
3293 &Segment::from_path(path),
3300 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3301 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3302 Ok(path_res.base_res())
3304 PathResult::NonModule(..) => Err((
3306 ResolutionError::FailedToResolve {
3307 label: String::from("type-relative paths are not supported in this context"),
3311 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3312 PathResult::Failed { span, label, suggestion, .. } => {
3313 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3318 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3319 let mut seg = ast::PathSegment::from_ident(ident);
3320 seg.id = self.next_node_id();
3325 pub fn graph_root(&self) -> Module<'a> {
3330 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3334 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3336 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3337 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3341 fn names_to_string(names: &[Symbol]) -> String {
3342 let mut result = String::new();
3343 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3345 result.push_str("::");
3347 if Ident::with_dummy_span(*name).is_raw_guess() {
3348 result.push_str("r#");
3350 result.push_str(&name.as_str());
3355 fn path_names_to_string(path: &Path) -> String {
3356 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3359 /// A somewhat inefficient routine to obtain the name of a module.
3360 fn module_to_string(module: Module<'_>) -> Option<String> {
3361 let mut names = Vec::new();
3363 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3364 if let ModuleKind::Def(.., name) = module.kind {
3365 if let Some(parent) = module.parent {
3367 collect_mod(names, parent);
3370 names.push(Symbol::intern("<opaque>"));
3371 collect_mod(names, module.parent.unwrap());
3374 collect_mod(&mut names, module);
3376 if names.is_empty() {
3380 Some(names_to_string(&names))
3383 #[derive(Copy, Clone, Debug)]
3385 /// Do not issue the lint.
3388 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3389 /// In this case, we can take the span of that path.
3392 /// This lint comes from a `use` statement. In this case, what we
3393 /// care about really is the *root* `use` statement; e.g., if we
3394 /// have nested things like `use a::{b, c}`, we care about the
3396 UsePath { root_id: NodeId, root_span: Span },
3398 /// This is the "trait item" from a fully qualified path. For example,
3399 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3400 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3401 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3405 fn node_id(&self) -> Option<NodeId> {
3407 CrateLint::No => None,
3408 CrateLint::SimplePath(id)
3409 | CrateLint::UsePath { root_id: id, .. }
3410 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3415 pub fn provide(providers: &mut Providers) {
3416 late::lifetimes::provide(providers);