1 //! This crate is responsible for the part of name resolution that doesn't require type checker.
3 //! Module structure of the crate is built here.
4 //! Paths in macros, imports, expressions, types, patterns are resolved here.
5 //! Label and lifetime names are resolved here as well.
7 //! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
9 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
10 #![feature(bool_to_option)]
11 #![feature(crate_visibility_modifier)]
12 #![feature(label_break_value)]
14 #![recursion_limit = "256"]
16 pub use rustc_hir::def::{Namespace, PerNS};
20 use rustc::hir::exports::ExportMap;
21 use rustc::hir::map::{DefKey, Definitions};
23 use rustc::middle::cstore::{CrateStore, MetadataLoaderDyn};
25 use rustc::ty::query::Providers;
26 use rustc::ty::{self, DefIdTree, ResolverOutputs};
27 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
28 use rustc_data_structures::ptr_key::PtrKey;
29 use rustc_data_structures::sync::Lrc;
30 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
31 use rustc_expand::base::SyntaxExtension;
32 use rustc_hir::def::Namespace::*;
33 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
34 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
35 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
36 use rustc_hir::{GlobMap, TraitMap};
37 use rustc_metadata::creader::{CStore, CrateLoader};
38 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
39 use rustc_session::node_id::{NodeMap, NodeSet};
40 use rustc_session::Session;
41 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
42 use rustc_span::source_map::Spanned;
43 use rustc_span::symbol::{kw, sym};
44 use rustc_span::{Span, DUMMY_SP};
45 use syntax::ast::{self, FloatTy, Ident, IntTy, Name, NodeId, UintTy};
46 use syntax::ast::{Crate, CRATE_NODE_ID};
47 use syntax::ast::{ItemKind, Path};
49 use syntax::print::pprust;
50 use syntax::unwrap_or;
51 use syntax::visit::{self, Visitor};
54 use std::cell::{Cell, RefCell};
55 use std::collections::BTreeSet;
56 use std::{cmp, fmt, iter, ptr};
58 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
59 use diagnostics::{ImportSuggestion, Suggestion};
60 use imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver, NameResolution};
61 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
62 use macros::{LegacyBinding, LegacyScope};
64 type Res = def::Res<NodeId>;
66 mod build_reduced_graph;
80 #[derive(Copy, Clone, PartialEq, Debug)]
81 pub enum Determinacy {
87 fn determined(determined: bool) -> Determinacy {
88 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
92 /// A specific scope in which a name can be looked up.
93 /// This enum is currently used only for early resolution (imports and macros),
94 /// but not for late resolution yet.
95 #[derive(Clone, Copy)]
97 DeriveHelpers(ExpnId),
99 MacroRules(LegacyScope<'a>),
111 /// Names from different contexts may want to visit different subsets of all specific scopes
112 /// with different restrictions when looking up the resolution.
113 /// This enum is currently used only for early resolution (imports and macros),
114 /// but not for late resolution yet.
116 /// All scopes with the given namespace.
117 All(Namespace, /*is_import*/ bool),
118 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
119 AbsolutePath(Namespace),
120 /// All scopes with macro namespace and the given macro kind restriction.
124 /// Everything you need to know about a name's location to resolve it.
125 /// Serves as a starting point for the scope visitor.
126 /// This struct is currently used only for early resolution (imports and macros),
127 /// but not for late resolution yet.
128 #[derive(Clone, Copy, Debug)]
129 pub struct ParentScope<'a> {
132 legacy: LegacyScope<'a>,
133 derives: &'a [ast::Path],
136 impl<'a> ParentScope<'a> {
137 /// Creates a parent scope with the passed argument used as the module scope component,
138 /// and other scope components set to default empty values.
139 pub fn module(module: Module<'a>) -> ParentScope<'a> {
140 ParentScope { module, expansion: ExpnId::root(), legacy: LegacyScope::Empty, derives: &[] }
145 struct BindingError {
147 origin: BTreeSet<Span>,
148 target: BTreeSet<Span>,
152 impl PartialOrd for BindingError {
153 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
154 Some(self.cmp(other))
158 impl PartialEq for BindingError {
159 fn eq(&self, other: &BindingError) -> bool {
160 self.name == other.name
164 impl Ord for BindingError {
165 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
166 self.name.cmp(&other.name)
170 enum ResolutionError<'a> {
171 /// Error E0401: can't use type or const parameters from outer function.
172 GenericParamsFromOuterFunction(Res, HasGenericParams),
173 /// Error E0403: the name is already used for a type or const parameter in this generic
175 NameAlreadyUsedInParameterList(Name, Span),
176 /// Error E0407: method is not a member of trait.
177 MethodNotMemberOfTrait(Name, &'a str),
178 /// Error E0437: type is not a member of trait.
179 TypeNotMemberOfTrait(Name, &'a str),
180 /// Error E0438: const is not a member of trait.
181 ConstNotMemberOfTrait(Name, &'a str),
182 /// Error E0408: variable `{}` is not bound in all patterns.
183 VariableNotBoundInPattern(&'a BindingError),
184 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
185 VariableBoundWithDifferentMode(Name, Span),
186 /// Error E0415: identifier is bound more than once in this parameter list.
187 IdentifierBoundMoreThanOnceInParameterList(&'a str),
188 /// Error E0416: identifier is bound more than once in the same pattern.
189 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
190 /// Error E0426: use of undeclared label.
191 UndeclaredLabel(&'a str, Option<Name>),
192 /// Error E0429: `self` imports are only allowed within a `{ }` list.
193 SelfImportsOnlyAllowedWithin,
194 /// Error E0430: `self` import can only appear once in the list.
195 SelfImportCanOnlyAppearOnceInTheList,
196 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
197 SelfImportOnlyInImportListWithNonEmptyPrefix,
198 /// Error E0433: failed to resolve.
199 FailedToResolve { label: String, suggestion: Option<Suggestion> },
200 /// Error E0434: can't capture dynamic environment in a fn item.
201 CannotCaptureDynamicEnvironmentInFnItem,
202 /// Error E0435: attempt to use a non-constant value in a constant.
203 AttemptToUseNonConstantValueInConstant,
204 /// Error E0530: `X` bindings cannot shadow `Y`s.
205 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
206 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
207 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
208 /// Error E0735: type parameters with a default cannot use `Self`
209 SelfInTyParamDefault,
212 enum VisResolutionError<'a> {
213 Relative2018(Span, &'a ast::Path),
215 FailedToResolve(Span, String, Option<Suggestion>),
216 ExpectedFound(Span, String, Res),
221 // A minimal representation of a path segment. We use this in resolve because
222 // we synthesize 'path segments' which don't have the rest of an AST or HIR
224 #[derive(Clone, Copy, Debug)]
231 fn from_path(path: &Path) -> Vec<Segment> {
232 path.segments.iter().map(|s| s.into()).collect()
235 fn from_ident(ident: Ident) -> Segment {
236 Segment { ident, id: None }
239 fn names_to_string(segments: &[Segment]) -> String {
240 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
244 impl<'a> From<&'a ast::PathSegment> for Segment {
245 fn from(seg: &'a ast::PathSegment) -> Segment {
246 Segment { ident: seg.ident, id: Some(seg.id) }
250 struct UsePlacementFinder {
251 target_module: NodeId,
256 impl UsePlacementFinder {
257 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
258 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
259 visit::walk_crate(&mut finder, krate);
260 (finder.span, finder.found_use)
264 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
267 module: &'tcx ast::Mod,
269 _: &[ast::Attribute],
272 if self.span.is_some() {
275 if node_id != self.target_module {
276 visit::walk_mod(self, module);
279 // find a use statement
280 for item in &module.items {
282 ItemKind::Use(..) => {
283 // don't suggest placing a use before the prelude
284 // import or other generated ones
285 if !item.span.from_expansion() {
286 self.span = Some(item.span.shrink_to_lo());
287 self.found_use = true;
291 // don't place use before extern crate
292 ItemKind::ExternCrate(_) => {}
293 // but place them before the first other item
295 if self.span.map_or(true, |span| item.span < span) {
296 if !item.span.from_expansion() {
297 // don't insert between attributes and an item
298 if item.attrs.is_empty() {
299 self.span = Some(item.span.shrink_to_lo());
301 // find the first attribute on the item
302 for attr in &item.attrs {
303 if self.span.map_or(true, |span| attr.span < span) {
304 self.span = Some(attr.span.shrink_to_lo());
316 /// An intermediate resolution result.
318 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
319 /// items are visible in their whole block, while `Res`es only from the place they are defined
322 enum LexicalScopeBinding<'a> {
323 Item(&'a NameBinding<'a>),
327 impl<'a> LexicalScopeBinding<'a> {
328 fn item(self) -> Option<&'a NameBinding<'a>> {
330 LexicalScopeBinding::Item(binding) => Some(binding),
335 fn res(self) -> Res {
337 LexicalScopeBinding::Item(binding) => binding.res(),
338 LexicalScopeBinding::Res(res) => res,
343 #[derive(Copy, Clone, Debug)]
344 enum ModuleOrUniformRoot<'a> {
348 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
349 CrateRootAndExternPrelude,
351 /// Virtual module that denotes resolution in extern prelude.
352 /// Used for paths starting with `::` on 2018 edition.
355 /// Virtual module that denotes resolution in current scope.
356 /// Used only for resolving single-segment imports. The reason it exists is that import paths
357 /// are always split into two parts, the first of which should be some kind of module.
361 impl ModuleOrUniformRoot<'_> {
362 fn same_def(lhs: Self, rhs: Self) -> bool {
364 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
365 lhs.def_id() == rhs.def_id()
368 ModuleOrUniformRoot::CrateRootAndExternPrelude,
369 ModuleOrUniformRoot::CrateRootAndExternPrelude,
371 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
372 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
378 #[derive(Clone, Debug)]
379 enum PathResult<'a> {
380 Module(ModuleOrUniformRoot<'a>),
381 NonModule(PartialRes),
386 suggestion: Option<Suggestion>,
387 is_error_from_last_segment: bool,
392 /// An anonymous module; e.g., just a block.
397 /// { // This is an anonymous module
398 /// f(); // This resolves to (2) as we are inside the block.
401 /// f(); // Resolves to (1)
405 /// Any module with a name.
409 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
410 /// * A trait or an enum (it implicitly contains associated types, methods and variant
412 Def(DefKind, DefId, Name),
416 /// Get name of the module.
417 pub fn name(&self) -> Option<Name> {
419 ModuleKind::Block(..) => None,
420 ModuleKind::Def(.., name) => Some(*name),
425 /// A key that identifies a binding in a given `Module`.
427 /// Multiple bindings in the same module can have the same key (in a valid
428 /// program) if all but one of them come from glob imports.
429 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
431 /// The identifier for the binding, aways the `modern` version of the
435 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
436 /// `_` in the expanded AST that introduced this binding.
440 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
442 /// One node in the tree of modules.
443 pub struct ModuleData<'a> {
444 parent: Option<Module<'a>>,
447 // The def id of the closest normal module (`mod`) ancestor (including this module).
448 normal_ancestor_id: DefId,
450 // Mapping between names and their (possibly in-progress) resolutions in this module.
451 // Resolutions in modules from other crates are not populated until accessed.
452 lazy_resolutions: Resolutions<'a>,
453 // True if this is a module from other crate that needs to be populated on access.
454 populate_on_access: Cell<bool>,
456 // Macro invocations that can expand into items in this module.
457 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
459 no_implicit_prelude: bool,
461 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
462 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
464 // Used to memoize the traits in this module for faster searches through all traits in scope.
465 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
467 /// Span of the module itself. Used for error reporting.
473 type Module<'a> = &'a ModuleData<'a>;
475 impl<'a> ModuleData<'a> {
477 parent: Option<Module<'a>>,
479 normal_ancestor_id: DefId,
487 lazy_resolutions: Default::default(),
488 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
489 unexpanded_invocations: Default::default(),
490 no_implicit_prelude: false,
491 glob_importers: RefCell::new(Vec::new()),
492 globs: RefCell::new(Vec::new()),
493 traits: RefCell::new(None),
499 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
501 R: AsMut<Resolver<'a>>,
502 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
504 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
505 name_resolution.borrow().binding.map(|binding| f(resolver, key.ident, key.ns, binding));
509 fn res(&self) -> Option<Res> {
511 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
516 fn def_id(&self) -> Option<DefId> {
518 ModuleKind::Def(_, def_id, _) => Some(def_id),
523 // `self` resolves to the first module ancestor that `is_normal`.
524 fn is_normal(&self) -> bool {
526 ModuleKind::Def(DefKind::Mod, _, _) => true,
531 fn is_trait(&self) -> bool {
533 ModuleKind::Def(DefKind::Trait, _, _) => true,
538 fn nearest_item_scope(&'a self) -> Module<'a> {
540 ModuleKind::Def(DefKind::Enum, ..) | ModuleKind::Def(DefKind::Trait, ..) => {
541 self.parent.expect("enum or trait module without a parent")
547 fn is_ancestor_of(&self, mut other: &Self) -> bool {
548 while !ptr::eq(self, other) {
549 if let Some(parent) = other.parent {
559 impl<'a> fmt::Debug for ModuleData<'a> {
560 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
561 write!(f, "{:?}", self.res())
565 /// Records a possibly-private value, type, or module definition.
566 #[derive(Clone, Debug)]
567 pub struct NameBinding<'a> {
568 kind: NameBindingKind<'a>,
569 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
575 pub trait ToNameBinding<'a> {
576 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
579 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
580 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
585 #[derive(Clone, Debug)]
586 enum NameBindingKind<'a> {
587 Res(Res, /* is_macro_export */ bool),
589 Import { binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>, used: Cell<bool> },
592 impl<'a> NameBindingKind<'a> {
593 /// Is this a name binding of a import?
594 fn is_import(&self) -> bool {
596 NameBindingKind::Import { .. } => true,
602 struct PrivacyError<'a> {
604 binding: &'a NameBinding<'a>,
608 struct UseError<'a> {
609 err: DiagnosticBuilder<'a>,
610 /// Attach `use` statements for these candidates.
611 candidates: Vec<ImportSuggestion>,
612 /// The `NodeId` of the module to place the use-statements in.
614 /// Whether the diagnostic should state that it's "better".
618 #[derive(Clone, Copy, PartialEq, Debug)]
631 fn descr(self) -> &'static str {
633 AmbiguityKind::Import => "name vs any other name during import resolution",
634 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
635 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
636 AmbiguityKind::LegacyVsModern => "`macro_rules` vs non-`macro_rules` from other module",
637 AmbiguityKind::GlobVsOuter => {
638 "glob import vs any other name from outer scope during import/macro resolution"
640 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
641 AmbiguityKind::GlobVsExpanded => {
642 "glob import vs macro-expanded name in the same \
643 module during import/macro resolution"
645 AmbiguityKind::MoreExpandedVsOuter => {
646 "macro-expanded name vs less macro-expanded name \
647 from outer scope during import/macro resolution"
653 /// Miscellaneous bits of metadata for better ambiguity error reporting.
654 #[derive(Clone, Copy, PartialEq)]
655 enum AmbiguityErrorMisc {
662 struct AmbiguityError<'a> {
665 b1: &'a NameBinding<'a>,
666 b2: &'a NameBinding<'a>,
667 misc1: AmbiguityErrorMisc,
668 misc2: AmbiguityErrorMisc,
671 impl<'a> NameBinding<'a> {
672 fn module(&self) -> Option<Module<'a>> {
674 NameBindingKind::Module(module) => Some(module),
675 NameBindingKind::Import { binding, .. } => binding.module(),
680 fn res(&self) -> Res {
682 NameBindingKind::Res(res, _) => res,
683 NameBindingKind::Module(module) => module.res().unwrap(),
684 NameBindingKind::Import { binding, .. } => binding.res(),
688 fn is_ambiguity(&self) -> bool {
689 self.ambiguity.is_some()
691 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
696 // We sometimes need to treat variants as `pub` for backwards compatibility.
697 fn pseudo_vis(&self) -> ty::Visibility {
698 if self.is_variant() && self.res().def_id().is_local() {
699 ty::Visibility::Public
705 fn is_variant(&self) -> bool {
707 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _)
708 | NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
713 fn is_extern_crate(&self) -> bool {
715 NameBindingKind::Import {
717 &ImportDirective { subclass: ImportDirectiveSubclass::ExternCrate { .. }, .. },
720 NameBindingKind::Module(&ModuleData {
721 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
723 }) => def_id.index == CRATE_DEF_INDEX,
728 fn is_import(&self) -> bool {
730 NameBindingKind::Import { .. } => true,
735 fn is_glob_import(&self) -> bool {
737 NameBindingKind::Import { directive, .. } => directive.is_glob(),
742 fn is_importable(&self) -> bool {
744 Res::Def(DefKind::AssocConst, _)
745 | Res::Def(DefKind::Method, _)
746 | Res::Def(DefKind::AssocTy, _) => false,
751 fn is_macro_def(&self) -> bool {
753 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
758 fn macro_kind(&self) -> Option<MacroKind> {
759 self.res().macro_kind()
762 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
763 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
764 // Then this function returns `true` if `self` may emerge from a macro *after* that
765 // in some later round and screw up our previously found resolution.
766 // See more detailed explanation in
767 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
768 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
769 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
770 // Expansions are partially ordered, so "may appear after" is an inversion of
771 // "certainly appears before or simultaneously" and includes unordered cases.
772 let self_parent_expansion = self.expansion;
773 let other_parent_expansion = binding.expansion;
774 let certainly_before_other_or_simultaneously =
775 other_parent_expansion.is_descendant_of(self_parent_expansion);
776 let certainly_before_invoc_or_simultaneously =
777 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
778 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
782 /// Interns the names of the primitive types.
784 /// All other types are defined somewhere and possibly imported, but the primitive ones need
785 /// special handling, since they have no place of origin.
786 struct PrimitiveTypeTable {
787 primitive_types: FxHashMap<Name, PrimTy>,
790 impl PrimitiveTypeTable {
791 fn new() -> PrimitiveTypeTable {
792 let mut table = FxHashMap::default();
794 table.insert(sym::bool, Bool);
795 table.insert(sym::char, Char);
796 table.insert(sym::f32, Float(FloatTy::F32));
797 table.insert(sym::f64, Float(FloatTy::F64));
798 table.insert(sym::isize, Int(IntTy::Isize));
799 table.insert(sym::i8, Int(IntTy::I8));
800 table.insert(sym::i16, Int(IntTy::I16));
801 table.insert(sym::i32, Int(IntTy::I32));
802 table.insert(sym::i64, Int(IntTy::I64));
803 table.insert(sym::i128, Int(IntTy::I128));
804 table.insert(sym::str, Str);
805 table.insert(sym::usize, Uint(UintTy::Usize));
806 table.insert(sym::u8, Uint(UintTy::U8));
807 table.insert(sym::u16, Uint(UintTy::U16));
808 table.insert(sym::u32, Uint(UintTy::U32));
809 table.insert(sym::u64, Uint(UintTy::U64));
810 table.insert(sym::u128, Uint(UintTy::U128));
811 Self { primitive_types: table }
815 #[derive(Debug, Default, Clone)]
816 pub struct ExternPreludeEntry<'a> {
817 extern_crate_item: Option<&'a NameBinding<'a>>,
818 pub introduced_by_item: bool,
821 /// The main resolver class.
823 /// This is the visitor that walks the whole crate.
824 pub struct Resolver<'a> {
825 session: &'a Session,
827 definitions: Definitions,
829 graph_root: Module<'a>,
831 prelude: Option<Module<'a>>,
832 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
834 /// N.B., this is used only for better diagnostics, not name resolution itself.
835 has_self: FxHashSet<DefId>,
837 /// Names of fields of an item `DefId` accessible with dot syntax.
838 /// Used for hints during error reporting.
839 field_names: FxHashMap<DefId, Vec<Spanned<Name>>>,
841 /// All imports known to succeed or fail.
842 determined_imports: Vec<&'a ImportDirective<'a>>,
844 /// All non-determined imports.
845 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
847 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
848 /// We are resolving a last import segment during import validation.
849 last_import_segment: bool,
850 /// This binding should be ignored during in-module resolution, so that we don't get
851 /// "self-confirming" import resolutions during import validation.
852 blacklisted_binding: Option<&'a NameBinding<'a>>,
854 /// The idents for the primitive types.
855 primitive_type_table: PrimitiveTypeTable,
857 /// Resolutions for nodes that have a single resolution.
858 partial_res_map: NodeMap<PartialRes>,
859 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
860 import_res_map: NodeMap<PerNS<Option<Res>>>,
861 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
862 label_res_map: NodeMap<NodeId>,
864 /// `CrateNum` resolutions of `extern crate` items.
865 extern_crate_map: NodeMap<CrateNum>,
866 export_map: ExportMap<NodeId>,
869 /// A map from nodes to anonymous modules.
870 /// Anonymous modules are pseudo-modules that are implicitly created around items
871 /// contained within blocks.
873 /// For example, if we have this:
881 /// There will be an anonymous module created around `g` with the ID of the
882 /// entry block for `f`.
883 block_map: NodeMap<Module<'a>>,
884 /// A fake module that contains no definition and no prelude. Used so that
885 /// some AST passes can generate identifiers that only resolve to local or
887 empty_module: Module<'a>,
888 module_map: FxHashMap<DefId, Module<'a>>,
889 extern_module_map: FxHashMap<DefId, Module<'a>>,
890 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
891 underscore_disambiguator: u32,
893 /// Maps glob imports to the names of items actually imported.
896 used_imports: FxHashSet<(NodeId, Namespace)>,
897 maybe_unused_trait_imports: NodeSet,
898 maybe_unused_extern_crates: Vec<(NodeId, Span)>,
900 /// Privacy errors are delayed until the end in order to deduplicate them.
901 privacy_errors: Vec<PrivacyError<'a>>,
902 /// Ambiguity errors are delayed for deduplication.
903 ambiguity_errors: Vec<AmbiguityError<'a>>,
904 /// `use` injections are delayed for better placement and deduplication.
905 use_injections: Vec<UseError<'a>>,
906 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
907 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
909 arenas: &'a ResolverArenas<'a>,
910 dummy_binding: &'a NameBinding<'a>,
912 crate_loader: CrateLoader<'a>,
913 macro_names: FxHashSet<Ident>,
914 builtin_macros: FxHashMap<Name, SyntaxExtension>,
915 registered_attrs: FxHashSet<Ident>,
916 registered_tools: FxHashSet<Ident>,
917 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
918 all_macros: FxHashMap<Name, Res>,
919 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
920 dummy_ext_bang: Lrc<SyntaxExtension>,
921 dummy_ext_derive: Lrc<SyntaxExtension>,
922 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
923 macro_defs: FxHashMap<ExpnId, DefId>,
924 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
925 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
926 unused_macros: NodeMap<Span>,
927 proc_macro_stubs: NodeSet,
928 /// Traces collected during macro resolution and validated when it's complete.
929 single_segment_macro_resolutions:
930 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
931 multi_segment_macro_resolutions:
932 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
933 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
934 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
935 /// Derive macros cannot modify the item themselves and have to store the markers in the global
936 /// context, so they attach the markers to derive container IDs using this resolver table.
937 containers_deriving_copy: FxHashSet<ExpnId>,
938 /// Parent scopes in which the macros were invoked.
939 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
940 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
941 /// Legacy scopes *produced* by expanding the macro invocations,
942 /// include all the `macro_rules` items and other invocations generated by them.
943 output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
944 /// Helper attributes that are in scope for the given expansion.
945 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
947 /// Avoid duplicated errors for "name already defined".
948 name_already_seen: FxHashMap<Name, Span>,
950 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
952 /// Table for mapping struct IDs into struct constructor IDs,
953 /// it's not used during normal resolution, only for better error reporting.
954 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
956 /// Features enabled for this crate.
957 active_features: FxHashSet<Name>,
959 /// Stores enum visibilities to properly build a reduced graph
960 /// when visiting the correspondent variants.
961 variant_vis: DefIdMap<ty::Visibility>,
963 lint_buffer: LintBuffer,
965 next_node_id: NodeId,
968 /// Nothing really interesting here; it just provides memory for the rest of the crate.
970 pub struct ResolverArenas<'a> {
971 modules: arena::TypedArena<ModuleData<'a>>,
972 local_modules: RefCell<Vec<Module<'a>>>,
973 name_bindings: arena::TypedArena<NameBinding<'a>>,
974 import_directives: arena::TypedArena<ImportDirective<'a>>,
975 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
976 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
977 ast_paths: arena::TypedArena<ast::Path>,
980 impl<'a> ResolverArenas<'a> {
981 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
982 let module = self.modules.alloc(module);
983 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
984 self.local_modules.borrow_mut().push(module);
988 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
989 self.local_modules.borrow()
991 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
992 self.name_bindings.alloc(name_binding)
994 fn alloc_import_directive(
996 import_directive: ImportDirective<'a>,
997 ) -> &'a ImportDirective<'_> {
998 self.import_directives.alloc(import_directive)
1000 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1001 self.name_resolutions.alloc(Default::default())
1003 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1004 self.legacy_bindings.alloc(binding)
1006 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1007 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1011 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1012 fn as_mut(&mut self) -> &mut Resolver<'a> {
1017 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1018 fn parent(self, id: DefId) -> Option<DefId> {
1020 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1021 _ => self.cstore().def_key(id).parent,
1023 .map(|index| DefId { index, ..id })
1027 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1028 /// the resolver is no longer needed as all the relevant information is inline.
1029 impl rustc_ast_lowering::Resolver for Resolver<'_> {
1030 fn def_key(&mut self, id: DefId) -> DefKey {
1031 if id.is_local() { self.definitions().def_key(id.index) } else { self.cstore().def_key(id) }
1034 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1035 self.cstore().item_generics_num_lifetimes(def_id, sess)
1038 fn resolve_str_path(
1041 crate_root: Option<Name>,
1042 components: &[Name],
1044 ) -> (ast::Path, Res) {
1045 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1046 let segments = iter::once(Ident::with_dummy_span(root))
1050 .chain(components.iter().cloned())
1051 .map(Ident::with_dummy_span),
1053 .map(|i| self.new_ast_path_segment(i))
1054 .collect::<Vec<_>>();
1056 let path = ast::Path { span, segments };
1058 let parent_scope = &ParentScope::module(self.graph_root);
1059 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1061 Err((span, error)) => {
1062 self.report_error(span, error);
1069 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1070 self.partial_res_map.get(&id).cloned()
1073 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1074 self.import_res_map.get(&id).cloned().unwrap_or_default()
1077 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1078 self.label_res_map.get(&id).cloned()
1081 fn definitions(&mut self) -> &mut Definitions {
1082 &mut self.definitions
1085 fn lint_buffer(&mut self) -> &mut LintBuffer {
1086 &mut self.lint_buffer
1089 fn next_node_id(&mut self) -> NodeId {
1094 impl<'a> Resolver<'a> {
1096 session: &'a Session,
1099 metadata_loader: &'a MetadataLoaderDyn,
1100 arenas: &'a ResolverArenas<'a>,
1102 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1103 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1104 let graph_root = arenas.alloc_module(ModuleData {
1105 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1106 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1108 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1109 let empty_module = arenas.alloc_module(ModuleData {
1110 no_implicit_prelude: true,
1119 let mut module_map = FxHashMap::default();
1120 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1122 let mut definitions = Definitions::default();
1123 definitions.create_root_def(crate_name, session.local_crate_disambiguator());
1125 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1129 .filter(|(_, entry)| entry.add_prelude)
1130 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1133 if !attr::contains_name(&krate.attrs, sym::no_core) {
1134 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1135 if !attr::contains_name(&krate.attrs, sym::no_std) {
1136 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1137 if session.rust_2018() {
1138 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1143 let (registered_attrs, registered_tools) =
1144 macros::registered_attrs_and_tools(session, &krate.attrs);
1146 let mut invocation_parent_scopes = FxHashMap::default();
1147 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1149 let mut macro_defs = FxHashMap::default();
1150 macro_defs.insert(ExpnId::root(), root_def_id);
1152 let features = session.features_untracked();
1153 let non_macro_attr =
1154 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1161 // The outermost module has def ID 0; this is not reflected in the
1167 has_self: FxHashSet::default(),
1168 field_names: FxHashMap::default(),
1170 determined_imports: Vec::new(),
1171 indeterminate_imports: Vec::new(),
1173 last_import_segment: false,
1174 blacklisted_binding: None,
1176 primitive_type_table: PrimitiveTypeTable::new(),
1178 partial_res_map: Default::default(),
1179 import_res_map: Default::default(),
1180 label_res_map: Default::default(),
1181 extern_crate_map: Default::default(),
1182 export_map: FxHashMap::default(),
1183 trait_map: Default::default(),
1184 underscore_disambiguator: 0,
1187 block_map: Default::default(),
1188 extern_module_map: FxHashMap::default(),
1189 binding_parent_modules: FxHashMap::default(),
1190 ast_transform_scopes: FxHashMap::default(),
1192 glob_map: Default::default(),
1194 used_imports: FxHashSet::default(),
1195 maybe_unused_trait_imports: Default::default(),
1196 maybe_unused_extern_crates: Vec::new(),
1198 privacy_errors: Vec::new(),
1199 ambiguity_errors: Vec::new(),
1200 use_injections: Vec::new(),
1201 macro_expanded_macro_export_errors: BTreeSet::new(),
1204 dummy_binding: arenas.alloc_name_binding(NameBinding {
1205 kind: NameBindingKind::Res(Res::Err, false),
1207 expansion: ExpnId::root(),
1209 vis: ty::Visibility::Public,
1212 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1213 macro_names: FxHashSet::default(),
1214 builtin_macros: Default::default(),
1217 macro_use_prelude: FxHashMap::default(),
1218 all_macros: FxHashMap::default(),
1219 macro_map: FxHashMap::default(),
1220 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1221 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1222 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1223 invocation_parent_scopes,
1224 output_legacy_scopes: Default::default(),
1225 helper_attrs: Default::default(),
1227 local_macro_def_scopes: FxHashMap::default(),
1228 name_already_seen: FxHashMap::default(),
1229 potentially_unused_imports: Vec::new(),
1230 struct_constructors: Default::default(),
1231 unused_macros: Default::default(),
1232 proc_macro_stubs: Default::default(),
1233 single_segment_macro_resolutions: Default::default(),
1234 multi_segment_macro_resolutions: Default::default(),
1235 builtin_attrs: Default::default(),
1236 containers_deriving_copy: Default::default(),
1237 active_features: features
1238 .declared_lib_features
1240 .map(|(feat, ..)| *feat)
1241 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1243 variant_vis: Default::default(),
1244 lint_buffer: LintBuffer::default(),
1245 next_node_id: NodeId::from_u32(1),
1249 pub fn next_node_id(&mut self) -> NodeId {
1254 .expect("input too large; ran out of NodeIds");
1255 self.next_node_id = ast::NodeId::from_usize(next);
1259 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1260 &mut self.lint_buffer
1263 pub fn arenas() -> ResolverArenas<'a> {
1267 pub fn into_outputs(self) -> ResolverOutputs {
1269 definitions: self.definitions,
1270 cstore: Box::new(self.crate_loader.into_cstore()),
1271 extern_crate_map: self.extern_crate_map,
1272 export_map: self.export_map,
1273 trait_map: self.trait_map,
1274 glob_map: self.glob_map,
1275 maybe_unused_trait_imports: self.maybe_unused_trait_imports,
1276 maybe_unused_extern_crates: self.maybe_unused_extern_crates,
1277 extern_prelude: self
1280 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1285 pub fn clone_outputs(&self) -> ResolverOutputs {
1287 definitions: self.definitions.clone(),
1288 cstore: Box::new(self.cstore().clone()),
1289 extern_crate_map: self.extern_crate_map.clone(),
1290 export_map: self.export_map.clone(),
1291 trait_map: self.trait_map.clone(),
1292 glob_map: self.glob_map.clone(),
1293 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1294 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1295 extern_prelude: self
1298 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1303 pub fn cstore(&self) -> &CStore {
1304 self.crate_loader.cstore()
1307 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1308 self.non_macro_attrs[mark_used as usize].clone()
1311 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1313 MacroKind::Bang => self.dummy_ext_bang.clone(),
1314 MacroKind::Derive => self.dummy_ext_derive.clone(),
1315 MacroKind::Attr => self.non_macro_attr(true),
1319 /// Runs the function on each namespace.
1320 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1326 fn is_builtin_macro(&mut self, res: Res) -> bool {
1327 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1330 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1332 match self.macro_defs.get(&ctxt.outer_expn()) {
1333 Some(&def_id) => return def_id,
1334 None => ctxt.remove_mark(),
1339 /// Entry point to crate resolution.
1340 pub fn resolve_crate(&mut self, krate: &Crate) {
1341 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1343 ImportResolver { r: self }.finalize_imports();
1344 self.finalize_macro_resolutions();
1346 self.late_resolve_crate(krate);
1348 self.check_unused(krate);
1349 self.report_errors(krate);
1350 self.crate_loader.postprocess(krate);
1357 normal_ancestor_id: DefId,
1361 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1362 self.arenas.alloc_module(module)
1365 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1366 let ident = ident.modern();
1367 let disambiguator = if ident.name == kw::Underscore {
1368 self.underscore_disambiguator += 1;
1369 self.underscore_disambiguator
1373 BindingKey { ident, ns, disambiguator }
1376 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1377 if module.populate_on_access.get() {
1378 module.populate_on_access.set(false);
1379 self.build_reduced_graph_external(module);
1381 &module.lazy_resolutions
1388 ) -> &'a RefCell<NameResolution<'a>> {
1390 .resolutions(module)
1393 .or_insert_with(|| self.arenas.alloc_name_resolution())
1400 used_binding: &'a NameBinding<'a>,
1401 is_lexical_scope: bool,
1403 if let Some((b2, kind)) = used_binding.ambiguity {
1404 self.ambiguity_errors.push(AmbiguityError {
1409 misc1: AmbiguityErrorMisc::None,
1410 misc2: AmbiguityErrorMisc::None,
1413 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1414 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1415 // but not introduce it, as used if they are accessed from lexical scope.
1416 if is_lexical_scope {
1417 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1418 if let Some(crate_item) = entry.extern_crate_item {
1419 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1426 directive.used.set(true);
1427 self.used_imports.insert((directive.id, ns));
1428 self.add_to_glob_map(&directive, ident);
1429 self.record_use(ident, ns, binding, false);
1434 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
1435 if directive.is_glob() {
1436 self.glob_map.entry(directive.id).or_default().insert(ident.name);
1440 /// A generic scope visitor.
1441 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1442 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1445 scope_set: ScopeSet,
1446 parent_scope: &ParentScope<'a>,
1448 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1450 // General principles:
1451 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1452 // built into the language or standard library. This way we can add new names into the
1453 // language or standard library without breaking user code.
1454 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1455 // Places to search (in order of decreasing priority):
1457 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1458 // (open set, not controlled).
1459 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1460 // (open, not controlled).
1461 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1462 // 4. Tool modules (closed, controlled right now, but not in the future).
1463 // 5. Standard library prelude (de-facto closed, controlled).
1464 // 6. Language prelude (closed, controlled).
1466 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1467 // (open set, not controlled).
1468 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1469 // (open, not controlled).
1470 // 3. Standard library prelude (de-facto closed, controlled).
1472 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1473 // are currently reported as errors. They should be higher in priority than preludes
1474 // and probably even names in modules according to the "general principles" above. They
1475 // also should be subject to restricted shadowing because are effectively produced by
1476 // derives (you need to resolve the derive first to add helpers into scope), but they
1477 // should be available before the derive is expanded for compatibility.
1478 // It's mess in general, so we are being conservative for now.
1479 // 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
1480 // priority than prelude macros, but create ambiguities with macros in modules.
1481 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1482 // (open, not controlled). Have higher priority than prelude macros, but create
1483 // ambiguities with `macro_rules`.
1484 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1485 // 4a. User-defined prelude from macro-use
1486 // (open, the open part is from macro expansions, not controlled).
1487 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1488 // 4c. Standard library prelude (de-facto closed, controlled).
1489 // 6. Language prelude: builtin attributes (closed, controlled).
1491 let rust_2015 = ident.span.rust_2015();
1492 let (ns, macro_kind, is_absolute_path) = match scope_set {
1493 ScopeSet::All(ns, _) => (ns, None, false),
1494 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1495 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1497 // Jump out of trait or enum modules, they do not act as scopes.
1498 let module = parent_scope.module.nearest_item_scope();
1499 let mut scope = match ns {
1500 _ if is_absolute_path => Scope::CrateRoot,
1501 TypeNS | ValueNS => Scope::Module(module),
1502 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1504 let mut ident = ident.modern();
1505 let mut use_prelude = !module.no_implicit_prelude;
1508 let visit = match scope {
1509 // Derive helpers are not in scope when resolving derives in the same container.
1510 Scope::DeriveHelpers(expn_id) => {
1511 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1513 Scope::DeriveHelpersCompat => true,
1514 Scope::MacroRules(..) => true,
1515 Scope::CrateRoot => true,
1516 Scope::Module(..) => true,
1517 Scope::RegisteredAttrs => use_prelude,
1518 Scope::MacroUsePrelude => use_prelude || rust_2015,
1519 Scope::BuiltinAttrs => true,
1520 Scope::ExternPrelude => use_prelude || is_absolute_path,
1521 Scope::ToolPrelude => use_prelude,
1522 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1523 Scope::BuiltinTypes => true,
1527 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1528 return break_result;
1532 scope = match scope {
1533 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1534 // Derive helpers are not visible to code generated by bang or derive macros.
1535 let expn_data = expn_id.expn_data();
1536 match expn_data.kind {
1538 | ExpnKind::Macro(MacroKind::Bang, _)
1539 | ExpnKind::Macro(MacroKind::Derive, _) => Scope::DeriveHelpersCompat,
1540 _ => Scope::DeriveHelpers(expn_data.parent),
1543 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1544 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.legacy),
1545 Scope::MacroRules(legacy_scope) => match legacy_scope {
1546 LegacyScope::Binding(binding) => Scope::MacroRules(binding.parent_legacy_scope),
1547 LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
1548 self.output_legacy_scopes
1551 .unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy),
1553 LegacyScope::Empty => Scope::Module(module),
1555 Scope::CrateRoot => match ns {
1557 ident.span.adjust(ExpnId::root());
1558 Scope::ExternPrelude
1560 ValueNS | MacroNS => break,
1562 Scope::Module(module) => {
1563 use_prelude = !module.no_implicit_prelude;
1564 match self.hygienic_lexical_parent(module, &mut ident.span) {
1565 Some(parent_module) => Scope::Module(parent_module),
1567 ident.span.adjust(ExpnId::root());
1569 TypeNS => Scope::ExternPrelude,
1570 ValueNS => Scope::StdLibPrelude,
1571 MacroNS => Scope::RegisteredAttrs,
1576 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1577 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1578 Scope::BuiltinAttrs => break, // nowhere else to search
1579 Scope::ExternPrelude if is_absolute_path => break,
1580 Scope::ExternPrelude => Scope::ToolPrelude,
1581 Scope::ToolPrelude => Scope::StdLibPrelude,
1582 Scope::StdLibPrelude => match ns {
1583 TypeNS => Scope::BuiltinTypes,
1584 ValueNS => break, // nowhere else to search
1585 MacroNS => Scope::BuiltinAttrs,
1587 Scope::BuiltinTypes => break, // nowhere else to search
1594 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1595 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1596 /// `ident` in the first scope that defines it (or None if no scopes define it).
1598 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1599 /// the items are defined in the block. For example,
1602 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1605 /// g(); // This resolves to the local variable `g` since it shadows the item.
1609 /// Invariant: This must only be called during main resolution, not during
1610 /// import resolution.
1611 fn resolve_ident_in_lexical_scope(
1615 parent_scope: &ParentScope<'a>,
1616 record_used_id: Option<NodeId>,
1619 ) -> Option<LexicalScopeBinding<'a>> {
1620 assert!(ns == TypeNS || ns == ValueNS);
1621 if ident.name == kw::Invalid {
1622 return Some(LexicalScopeBinding::Res(Res::Err));
1624 let (general_span, modern_span) = if ident.name == kw::SelfUpper {
1625 // FIXME(jseyfried) improve `Self` hygiene
1626 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1627 (empty_span, empty_span)
1628 } else if ns == TypeNS {
1629 let modern_span = ident.span.modern();
1630 (modern_span, modern_span)
1632 (ident.span.modern_and_legacy(), ident.span.modern())
1634 ident.span = general_span;
1635 let modern_ident = Ident { span: modern_span, ..ident };
1637 // Walk backwards up the ribs in scope.
1638 let record_used = record_used_id.is_some();
1639 let mut module = self.graph_root;
1640 for i in (0..ribs.len()).rev() {
1641 debug!("walk rib\n{:?}", ribs[i].bindings);
1642 // Use the rib kind to determine whether we are resolving parameters
1643 // (modern hygiene) or local variables (legacy hygiene).
1644 let rib_ident = if ribs[i].kind.contains_params() { modern_ident } else { ident };
1645 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1646 // The ident resolves to a type parameter or local variable.
1647 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1657 module = match ribs[i].kind {
1658 ModuleRibKind(module) => module,
1659 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1660 // If an invocation of this macro created `ident`, give up on `ident`
1661 // and switch to `ident`'s source from the macro definition.
1662 ident.span.remove_mark();
1668 let item = self.resolve_ident_in_module_unadjusted(
1669 ModuleOrUniformRoot::Module(module),
1676 if let Ok(binding) = item {
1677 // The ident resolves to an item.
1678 return Some(LexicalScopeBinding::Item(binding));
1682 ModuleKind::Block(..) => {} // We can see through blocks
1687 ident = modern_ident;
1688 let mut poisoned = None;
1690 let opt_module = if let Some(node_id) = record_used_id {
1691 self.hygienic_lexical_parent_with_compatibility_fallback(
1698 self.hygienic_lexical_parent(module, &mut ident.span)
1700 module = unwrap_or!(opt_module, break);
1701 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1702 let result = self.resolve_ident_in_module_unadjusted(
1703 ModuleOrUniformRoot::Module(module),
1706 adjusted_parent_scope,
1713 if let Some(node_id) = poisoned {
1714 self.lint_buffer.buffer_lint_with_diagnostic(
1715 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1718 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1719 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1722 return Some(LexicalScopeBinding::Item(binding));
1724 Err(Determined) => continue,
1725 Err(Undetermined) => {
1726 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1731 if !module.no_implicit_prelude {
1732 ident.span.adjust(ExpnId::root());
1734 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1735 return Some(LexicalScopeBinding::Item(binding));
1737 if let Some(ident) = self.registered_tools.get(&ident) {
1739 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1740 .to_name_binding(self.arenas);
1741 return Some(LexicalScopeBinding::Item(binding));
1744 if let Some(prelude) = self.prelude {
1745 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1746 ModuleOrUniformRoot::Module(prelude),
1753 return Some(LexicalScopeBinding::Item(binding));
1759 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1761 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1762 .to_name_binding(self.arenas);
1763 return Some(LexicalScopeBinding::Item(binding));
1770 fn hygienic_lexical_parent(
1774 ) -> Option<Module<'a>> {
1775 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1776 return Some(self.macro_def_scope(span.remove_mark()));
1779 if let ModuleKind::Block(..) = module.kind {
1780 return Some(module.parent.unwrap().nearest_item_scope());
1786 fn hygienic_lexical_parent_with_compatibility_fallback(
1791 poisoned: &mut Option<NodeId>,
1792 ) -> Option<Module<'a>> {
1793 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1797 // We need to support the next case under a deprecation warning
1800 // ---- begin: this comes from a proc macro derive
1801 // mod implementation_details {
1802 // // Note that `MyStruct` is not in scope here.
1803 // impl SomeTrait for MyStruct { ... }
1807 // So we have to fall back to the module's parent during lexical resolution in this case.
1808 if let Some(parent) = module.parent {
1809 // Inner module is inside the macro, parent module is outside of the macro.
1810 if module.expansion != parent.expansion
1811 && module.expansion.is_descendant_of(parent.expansion)
1813 // The macro is a proc macro derive
1814 if let Some(&def_id) = self.macro_defs.get(&module.expansion) {
1815 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1816 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1817 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1818 *poisoned = Some(node_id);
1819 return module.parent;
1830 fn resolve_ident_in_module(
1832 module: ModuleOrUniformRoot<'a>,
1835 parent_scope: &ParentScope<'a>,
1838 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1839 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1840 .map_err(|(determinacy, _)| determinacy)
1843 fn resolve_ident_in_module_ext(
1845 module: ModuleOrUniformRoot<'a>,
1848 parent_scope: &ParentScope<'a>,
1851 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1852 let tmp_parent_scope;
1853 let mut adjusted_parent_scope = parent_scope;
1855 ModuleOrUniformRoot::Module(m) => {
1856 if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
1858 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1859 adjusted_parent_scope = &tmp_parent_scope;
1862 ModuleOrUniformRoot::ExternPrelude => {
1863 ident.span.modernize_and_adjust(ExpnId::root());
1865 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1869 let result = self.resolve_ident_in_module_unadjusted_ext(
1873 adjusted_parent_scope,
1881 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1882 let mut ctxt = ident.span.ctxt();
1883 let mark = if ident.name == kw::DollarCrate {
1884 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1885 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1886 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
1887 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
1888 // definitions actually produced by `macro` and `macro` definitions produced by
1889 // `macro_rules!`, but at least such configurations are not stable yet.
1890 ctxt = ctxt.modern_and_legacy();
1891 let mut iter = ctxt.marks().into_iter().rev().peekable();
1892 let mut result = None;
1893 // Find the last modern mark from the end if it exists.
1894 while let Some(&(mark, transparency)) = iter.peek() {
1895 if transparency == Transparency::Opaque {
1896 result = Some(mark);
1902 // Then find the last legacy mark from the end if it exists.
1903 for (mark, transparency) in iter {
1904 if transparency == Transparency::SemiTransparent {
1905 result = Some(mark);
1912 ctxt = ctxt.modern();
1913 ctxt.adjust(ExpnId::root())
1915 let module = match mark {
1916 Some(def) => self.macro_def_scope(def),
1917 None => return self.graph_root,
1919 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1922 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1923 let mut module = self.get_module(module.normal_ancestor_id);
1924 while module.span.ctxt().modern() != *ctxt {
1925 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1926 module = self.get_module(parent.normal_ancestor_id);
1934 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1935 parent_scope: &ParentScope<'a>,
1938 crate_lint: CrateLint,
1939 ) -> PathResult<'a> {
1940 self.resolve_path_with_ribs(
1951 fn resolve_path_with_ribs(
1954 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1955 parent_scope: &ParentScope<'a>,
1958 crate_lint: CrateLint,
1959 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1960 ) -> PathResult<'a> {
1961 let mut module = None;
1962 let mut allow_super = true;
1963 let mut second_binding = None;
1966 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
1967 path_span={:?}, crate_lint={:?})",
1968 path, opt_ns, record_used, path_span, crate_lint,
1971 for (i, &Segment { ident, id }) in path.iter().enumerate() {
1972 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
1973 let record_segment_res = |this: &mut Self, res| {
1975 if let Some(id) = id {
1976 if !this.partial_res_map.contains_key(&id) {
1977 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
1978 this.record_partial_res(id, PartialRes::new(res));
1984 let is_last = i == path.len() - 1;
1985 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1986 let name = ident.name;
1988 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
1991 if allow_super && name == kw::Super {
1992 let mut ctxt = ident.span.ctxt().modern();
1993 let self_module = match i {
1994 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
1996 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2000 if let Some(self_module) = self_module {
2001 if let Some(parent) = self_module.parent {
2002 module = Some(ModuleOrUniformRoot::Module(
2003 self.resolve_self(&mut ctxt, parent),
2008 let msg = "there are too many leading `super` keywords".to_string();
2009 return PathResult::Failed {
2013 is_error_from_last_segment: false,
2017 if name == kw::SelfLower {
2018 let mut ctxt = ident.span.ctxt().modern();
2019 module = Some(ModuleOrUniformRoot::Module(
2020 self.resolve_self(&mut ctxt, parent_scope.module),
2024 if name == kw::PathRoot && ident.span.rust_2018() {
2025 module = Some(ModuleOrUniformRoot::ExternPrelude);
2028 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2029 // `::a::b` from 2015 macro on 2018 global edition
2030 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2033 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2034 // `::a::b`, `crate::a::b` or `$crate::a::b`
2035 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2041 // Report special messages for path segment keywords in wrong positions.
2042 if ident.is_path_segment_keyword() && i != 0 {
2043 let name_str = if name == kw::PathRoot {
2044 "crate root".to_string()
2046 format!("`{}`", name)
2048 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2049 format!("global paths cannot start with {}", name_str)
2051 format!("{} in paths can only be used in start position", name_str)
2053 return PathResult::Failed {
2057 is_error_from_last_segment: false,
2061 let binding = if let Some(module) = module {
2062 self.resolve_ident_in_module(
2070 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2071 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2072 self.early_resolve_ident_in_lexical_scope(
2081 let record_used_id =
2082 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
2083 match self.resolve_ident_in_lexical_scope(
2091 // we found a locally-imported or available item/module
2092 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2093 // we found a local variable or type param
2094 Some(LexicalScopeBinding::Res(res))
2095 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2097 record_segment_res(self, res);
2098 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2103 _ => Err(Determinacy::determined(record_used)),
2110 second_binding = Some(binding);
2112 let res = binding.res();
2113 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2114 if let Some(next_module) = binding.module() {
2115 module = Some(ModuleOrUniformRoot::Module(next_module));
2116 record_segment_res(self, res);
2117 } else if res == Res::ToolMod && i + 1 != path.len() {
2118 if binding.is_import() {
2122 "cannot use a tool module through an import",
2124 .span_note(binding.span, "the tool module imported here")
2127 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2128 return PathResult::NonModule(PartialRes::new(res));
2129 } else if res == Res::Err {
2130 return PathResult::NonModule(PartialRes::new(Res::Err));
2131 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2132 self.lint_if_path_starts_with_module(
2138 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2143 let label = format!(
2144 "`{}` is {} {}, not a module",
2150 return PathResult::Failed {
2154 is_error_from_last_segment: is_last,
2158 Err(Undetermined) => return PathResult::Indeterminate,
2159 Err(Determined) => {
2160 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2161 if opt_ns.is_some() && !module.is_normal() {
2162 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2163 module.res().unwrap(),
2168 let module_res = match module {
2169 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2172 let (label, suggestion) = if module_res == self.graph_root.res() {
2173 let is_mod = |res| match res {
2174 Res::Def(DefKind::Mod, _) => true,
2177 let mut candidates = self.lookup_import_candidates(ident, TypeNS, is_mod);
2178 candidates.sort_by_cached_key(|c| {
2179 (c.path.segments.len(), pprust::path_to_string(&c.path))
2181 if let Some(candidate) = candidates.get(0) {
2183 String::from("unresolved import"),
2185 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2186 String::from("a similar path exists"),
2187 Applicability::MaybeIncorrect,
2190 } else if !ident.is_reserved() {
2191 (format!("maybe a missing crate `{}`?", ident), None)
2193 // the parser will already have complained about the keyword being used
2194 return PathResult::NonModule(PartialRes::new(Res::Err));
2197 (format!("use of undeclared type or module `{}`", ident), None)
2199 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
2201 return PathResult::Failed {
2205 is_error_from_last_segment: is_last,
2211 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2213 PathResult::Module(match module {
2214 Some(module) => module,
2215 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2216 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2220 fn lint_if_path_starts_with_module(
2222 crate_lint: CrateLint,
2225 second_binding: Option<&NameBinding<'_>>,
2227 let (diag_id, diag_span) = match crate_lint {
2228 CrateLint::No => return,
2229 CrateLint::SimplePath(id) => (id, path_span),
2230 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2231 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2234 let first_name = match path.get(0) {
2235 // In the 2018 edition this lint is a hard error, so nothing to do
2236 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2240 // We're only interested in `use` paths which should start with
2241 // `{{root}}` currently.
2242 if first_name != kw::PathRoot {
2247 // If this import looks like `crate::...` it's already good
2248 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2249 // Otherwise go below to see if it's an extern crate
2251 // If the path has length one (and it's `PathRoot` most likely)
2252 // then we don't know whether we're gonna be importing a crate or an
2253 // item in our crate. Defer this lint to elsewhere
2257 // If the first element of our path was actually resolved to an
2258 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2259 // warning, this looks all good!
2260 if let Some(binding) = second_binding {
2261 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
2262 // Careful: we still want to rewrite paths from
2263 // renamed extern crates.
2264 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
2270 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2271 self.lint_buffer.buffer_lint_with_diagnostic(
2272 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2275 "absolute paths must start with `self`, `super`, \
2276 `crate`, or an external crate name in the 2018 edition",
2281 // Validate a local resolution (from ribs).
2282 fn validate_res_from_ribs(
2289 all_ribs: &[Rib<'a>],
2291 debug!("validate_res_from_ribs({:?})", res);
2292 let ribs = &all_ribs[rib_index + 1..];
2294 // An invalid forward use of a type parameter from a previous default.
2295 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2297 let res_error = if rib_ident.name == kw::SelfUpper {
2298 ResolutionError::SelfInTyParamDefault
2300 ResolutionError::ForwardDeclaredTyParam
2302 self.report_error(span, res_error);
2304 assert_eq!(res, Res::Err);
2310 use ResolutionError::*;
2311 let mut res_err = None;
2317 | MacroDefinition(..)
2318 | ForwardTyParamBanRibKind => {
2319 // Nothing to do. Continue.
2321 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2322 // This was an attempt to access an upvar inside a
2323 // named function item. This is not allowed, so we
2326 // We don't immediately trigger a resolve error, because
2327 // we want certain other resolution errors (namely those
2328 // emitted for `ConstantItemRibKind` below) to take
2330 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2333 ConstantItemRibKind => {
2334 // Still doesn't deal with upvars
2336 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2342 if let Some(res_err) = res_err {
2343 self.report_error(span, res_err);
2347 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2349 let has_generic_params = match rib.kind {
2353 | MacroDefinition(..)
2354 | ForwardTyParamBanRibKind
2355 | ConstantItemRibKind => {
2356 // Nothing to do. Continue.
2359 // This was an attempt to use a type parameter outside its scope.
2360 ItemRibKind(has_generic_params) => has_generic_params,
2361 FnItemRibKind => HasGenericParams::Yes,
2367 ResolutionError::GenericParamsFromOuterFunction(
2376 Res::Def(DefKind::ConstParam, _) => {
2377 let mut ribs = ribs.iter().peekable();
2378 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2379 // When declaring const parameters inside function signatures, the first rib
2380 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2381 // (spuriously) conflicting with the const param.
2385 let has_generic_params = match rib.kind {
2386 ItemRibKind(has_generic_params) => has_generic_params,
2387 FnItemRibKind => HasGenericParams::Yes,
2391 // This was an attempt to use a const parameter outside its scope.
2395 ResolutionError::GenericParamsFromOuterFunction(
2409 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2410 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2411 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2412 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2416 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2417 vis.is_accessible_from(module.normal_ancestor_id, self)
2420 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2421 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2422 if !ptr::eq(module, old_module) {
2423 span_bug!(binding.span, "parent module is reset for binding");
2428 fn disambiguate_legacy_vs_modern(
2430 legacy: &'a NameBinding<'a>,
2431 modern: &'a NameBinding<'a>,
2433 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
2434 // is disambiguated to mitigate regressions from macro modularization.
2435 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2437 self.binding_parent_modules.get(&PtrKey(legacy)),
2438 self.binding_parent_modules.get(&PtrKey(modern)),
2440 (Some(legacy), Some(modern)) => {
2441 legacy.normal_ancestor_id == modern.normal_ancestor_id
2442 && modern.is_ancestor_of(legacy)
2448 fn report_errors(&mut self, krate: &Crate) {
2449 self.report_with_use_injections(krate);
2451 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2452 let msg = "macro-expanded `macro_export` macros from the current crate \
2453 cannot be referred to by absolute paths";
2454 self.lint_buffer.buffer_lint_with_diagnostic(
2455 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2459 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2463 for ambiguity_error in &self.ambiguity_errors {
2464 self.report_ambiguity_error(ambiguity_error);
2467 let mut reported_spans = FxHashSet::default();
2468 for error in &self.privacy_errors {
2469 if reported_spans.insert(error.dedup_span) {
2470 self.report_privacy_error(error);
2475 fn report_with_use_injections(&mut self, krate: &Crate) {
2476 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
2477 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
2478 if !candidates.is_empty() {
2479 diagnostics::show_candidates(&mut err, span, &candidates, better, found_use);
2485 fn report_conflict<'b>(
2490 new_binding: &NameBinding<'b>,
2491 old_binding: &NameBinding<'b>,
2493 // Error on the second of two conflicting names
2494 if old_binding.span.lo() > new_binding.span.lo() {
2495 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2498 let container = match parent.kind {
2499 ModuleKind::Def(DefKind::Mod, _, _) => "module",
2500 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
2501 ModuleKind::Block(..) => "block",
2505 let old_noun = match old_binding.is_import() {
2507 false => "definition",
2510 let new_participle = match new_binding.is_import() {
2515 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
2517 if let Some(s) = self.name_already_seen.get(&name) {
2523 let old_kind = match (ns, old_binding.module()) {
2524 (ValueNS, _) => "value",
2525 (MacroNS, _) => "macro",
2526 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2527 (TypeNS, Some(module)) if module.is_normal() => "module",
2528 (TypeNS, Some(module)) if module.is_trait() => "trait",
2529 (TypeNS, _) => "type",
2532 let msg = format!("the name `{}` is defined multiple times", name);
2534 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2535 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2536 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2537 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2538 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2540 _ => match (old_binding.is_import(), new_binding.is_import()) {
2541 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2542 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2543 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2548 "`{}` must be defined only once in the {} namespace of this {}",
2554 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2556 self.session.source_map().def_span(old_binding.span),
2557 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2560 // See https://github.com/rust-lang/rust/issues/32354
2561 use NameBindingKind::Import;
2562 let directive = match (&new_binding.kind, &old_binding.kind) {
2563 // If there are two imports where one or both have attributes then prefer removing the
2564 // import without attributes.
2565 (Import { directive: new, .. }, Import { directive: old, .. })
2567 !new_binding.span.is_dummy()
2568 && !old_binding.span.is_dummy()
2569 && (new.has_attributes || old.has_attributes)
2572 if old.has_attributes {
2573 Some((new, new_binding.span, true))
2575 Some((old, old_binding.span, true))
2578 // Otherwise prioritize the new binding.
2579 (Import { directive, .. }, other) if !new_binding.span.is_dummy() => {
2580 Some((directive, new_binding.span, other.is_import()))
2582 (other, Import { directive, .. }) if !old_binding.span.is_dummy() => {
2583 Some((directive, old_binding.span, other.is_import()))
2588 // Check if the target of the use for both bindings is the same.
2589 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2590 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2592 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2593 // Only suggest removing an import if both bindings are to the same def, if both spans
2594 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2595 // been introduced by a item.
2596 let should_remove_import = duplicate
2598 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2601 Some((directive, span, true)) if should_remove_import && directive.is_nested() => {
2602 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span)
2604 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
2605 // Simple case - remove the entire import. Due to the above match arm, this can
2606 // only be a single use so just remove it entirely.
2607 err.tool_only_span_suggestion(
2608 directive.use_span_with_attributes,
2609 "remove unnecessary import",
2611 Applicability::MaybeIncorrect,
2614 Some((directive, span, _)) => {
2615 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span)
2621 self.name_already_seen.insert(name, span);
2624 /// This function adds a suggestion to change the binding name of a new import that conflicts
2625 /// with an existing import.
2627 /// ```ignore (diagnostic)
2628 /// help: you can use `as` to change the binding name of the import
2630 /// LL | use foo::bar as other_bar;
2631 /// | ^^^^^^^^^^^^^^^^^^^^^
2633 fn add_suggestion_for_rename_of_use(
2635 err: &mut DiagnosticBuilder<'_>,
2637 directive: &ImportDirective<'_>,
2640 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2641 format!("Other{}", name)
2643 format!("other_{}", name)
2646 let mut suggestion = None;
2647 match directive.subclass {
2648 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } => {
2649 suggestion = Some(format!("self as {}", suggested_name))
2651 ImportDirectiveSubclass::SingleImport { source, .. } => {
2653 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2655 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2656 if pos <= snippet.len() {
2657 suggestion = Some(format!(
2661 if snippet.ends_with(";") { ";" } else { "" }
2667 ImportDirectiveSubclass::ExternCrate { source, target, .. } => {
2668 suggestion = Some(format!(
2669 "extern crate {} as {};",
2670 source.unwrap_or(target.name),
2674 _ => unreachable!(),
2677 let rename_msg = "you can use `as` to change the binding name of the import";
2678 if let Some(suggestion) = suggestion {
2679 err.span_suggestion(
2683 Applicability::MaybeIncorrect,
2686 err.span_label(binding_span, rename_msg);
2690 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2691 /// nested. In the following example, this function will be invoked to remove the `a` binding
2692 /// in the second use statement:
2694 /// ```ignore (diagnostic)
2695 /// use issue_52891::a;
2696 /// use issue_52891::{d, a, e};
2699 /// The following suggestion will be added:
2701 /// ```ignore (diagnostic)
2702 /// use issue_52891::{d, a, e};
2703 /// ^-- help: remove unnecessary import
2706 /// If the nested use contains only one import then the suggestion will remove the entire
2709 /// It is expected that the directive provided is a nested import - this isn't checked by the
2710 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2711 /// as characters expected by span manipulations won't be present.
2712 fn add_suggestion_for_duplicate_nested_use(
2714 err: &mut DiagnosticBuilder<'_>,
2715 directive: &ImportDirective<'_>,
2718 assert!(directive.is_nested());
2719 let message = "remove unnecessary import";
2721 // Two examples will be used to illustrate the span manipulations we're doing:
2723 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
2724 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
2725 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
2726 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
2728 let (found_closing_brace, span) =
2729 find_span_of_binding_until_next_binding(self.session, binding_span, directive.use_span);
2731 // If there was a closing brace then identify the span to remove any trailing commas from
2732 // previous imports.
2733 if found_closing_brace {
2734 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
2735 err.tool_only_span_suggestion(
2739 Applicability::MaybeIncorrect,
2742 // Remove the entire line if we cannot extend the span back, this indicates a
2743 // `issue_52891::{self}` case.
2744 err.span_suggestion(
2745 directive.use_span_with_attributes,
2748 Applicability::MaybeIncorrect,
2755 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
2758 fn extern_prelude_get(
2762 ) -> Option<&'a NameBinding<'a>> {
2763 if ident.is_path_segment_keyword() {
2764 // Make sure `self`, `super` etc produce an error when passed to here.
2767 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
2768 if let Some(binding) = entry.extern_crate_item {
2769 if !speculative && entry.introduced_by_item {
2770 self.record_use(ident, TypeNS, binding, false);
2774 let crate_id = if !speculative {
2775 self.crate_loader.process_path_extern(ident.name, ident.span)
2776 } else if let Some(crate_id) =
2777 self.crate_loader.maybe_process_path_extern(ident.name, ident.span)
2783 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2785 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
2786 .to_name_binding(self.arenas),
2792 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
2793 /// isn't something that can be returned because it can't be made to live that long,
2794 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
2795 /// just that an error occurred.
2796 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
2797 pub fn resolve_str_path_error(
2803 ) -> Result<(ast::Path, Res), ()> {
2804 let path = if path_str.starts_with("::") {
2807 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
2808 .chain({ path_str.split("::").skip(1).map(Ident::from_str) })
2809 .map(|i| self.new_ast_path_segment(i))
2817 .map(Ident::from_str)
2818 .map(|i| self.new_ast_path_segment(i))
2822 let module = self.block_map.get(&module_id).copied().unwrap_or_else(|| {
2823 let def_id = self.definitions.local_def_id(module_id);
2824 self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
2826 let parent_scope = &ParentScope::module(module);
2827 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
2831 // Resolve a path passed from rustdoc or HIR lowering.
2832 fn resolve_ast_path(
2836 parent_scope: &ParentScope<'a>,
2837 ) -> Result<Res, (Span, ResolutionError<'a>)> {
2838 match self.resolve_path(
2839 &Segment::from_path(path),
2846 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
2847 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
2848 Ok(path_res.base_res())
2850 PathResult::NonModule(..) => Err((
2852 ResolutionError::FailedToResolve {
2853 label: String::from("type-relative paths are not supported in this context"),
2857 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
2858 PathResult::Failed { span, label, suggestion, .. } => {
2859 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
2864 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
2865 let mut seg = ast::PathSegment::from_ident(ident);
2866 seg.id = self.next_node_id();
2871 pub fn graph_root(&self) -> Module<'a> {
2876 pub fn all_macros(&self) -> &FxHashMap<Name, Res> {
2881 fn names_to_string(names: &[Name]) -> String {
2882 let mut result = String::new();
2883 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
2885 result.push_str("::");
2887 if Ident::with_dummy_span(*name).is_raw_guess() {
2888 result.push_str("r#");
2890 result.push_str(&name.as_str());
2895 fn path_names_to_string(path: &Path) -> String {
2896 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
2899 /// A somewhat inefficient routine to obtain the name of a module.
2900 fn module_to_string(module: Module<'_>) -> Option<String> {
2901 let mut names = Vec::new();
2903 fn collect_mod(names: &mut Vec<Name>, module: Module<'_>) {
2904 if let ModuleKind::Def(.., name) = module.kind {
2905 if let Some(parent) = module.parent {
2907 collect_mod(names, parent);
2910 names.push(Name::intern("<opaque>"));
2911 collect_mod(names, module.parent.unwrap());
2914 collect_mod(&mut names, module);
2916 if names.is_empty() {
2920 Some(names_to_string(&names))
2923 #[derive(Copy, Clone, Debug)]
2925 /// Do not issue the lint.
2928 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
2929 /// In this case, we can take the span of that path.
2932 /// This lint comes from a `use` statement. In this case, what we
2933 /// care about really is the *root* `use` statement; e.g., if we
2934 /// have nested things like `use a::{b, c}`, we care about the
2936 UsePath { root_id: NodeId, root_span: Span },
2938 /// This is the "trait item" from a fully qualified path. For example,
2939 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
2940 /// The `path_span` is the span of the to the trait itself (`X::Y`).
2941 QPathTrait { qpath_id: NodeId, qpath_span: Span },
2945 fn node_id(&self) -> Option<NodeId> {
2947 CrateLint::No => None,
2948 CrateLint::SimplePath(id)
2949 | CrateLint::UsePath { root_id: id, .. }
2950 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
2955 pub fn provide(providers: &mut Providers<'_>) {
2956 lifetimes::provide(providers);