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)]
13 #![recursion_limit = "256"]
15 pub use rustc_hir::def::{Namespace, PerNS};
19 use rustc::hir::exports::ExportMap;
20 use rustc::hir::map::{DefKey, Definitions};
22 use rustc::middle::cstore::{CrateStore, MetadataLoaderDyn};
24 use rustc::ty::query::Providers;
25 use rustc::ty::{self, DefIdTree, ResolverOutputs, TraitMap};
26 use rustc_ast_pretty::pprust;
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::GlobMap;
36 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
37 use rustc_metadata::creader::{CStore, CrateLoader};
38 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
39 use rustc_session::Session;
40 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
41 use rustc_span::source_map::Spanned;
42 use rustc_span::symbol::{kw, sym};
43 use rustc_span::{Span, DUMMY_SP};
44 use syntax::ast::{self, FloatTy, Ident, IntTy, Name, NodeId, UintTy};
45 use syntax::ast::{Crate, CRATE_NODE_ID};
46 use syntax::ast::{ItemKind, Path};
48 use syntax::node_id::{NodeMap, NodeSet};
49 use syntax::unwrap_or;
50 use syntax::visit::{self, Visitor};
53 use std::cell::{Cell, RefCell};
54 use std::collections::BTreeSet;
55 use std::{cmp, fmt, iter, ptr};
57 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
58 use diagnostics::{ImportSuggestion, Suggestion};
59 use imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver, NameResolution};
60 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
61 use macros::{LegacyBinding, LegacyScope};
63 type Res = def::Res<NodeId>;
65 mod build_reduced_graph;
79 #[derive(Copy, Clone, PartialEq, Debug)]
80 pub enum Determinacy {
86 fn determined(determined: bool) -> Determinacy {
87 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
91 /// A specific scope in which a name can be looked up.
92 /// This enum is currently used only for early resolution (imports and macros),
93 /// but not for late resolution yet.
94 #[derive(Clone, Copy)]
96 DeriveHelpers(ExpnId),
98 MacroRules(LegacyScope<'a>),
110 /// Names from different contexts may want to visit different subsets of all specific scopes
111 /// with different restrictions when looking up the resolution.
112 /// This enum is currently used only for early resolution (imports and macros),
113 /// but not for late resolution yet.
115 /// All scopes with the given namespace.
116 All(Namespace, /*is_import*/ bool),
117 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
118 AbsolutePath(Namespace),
119 /// All scopes with macro namespace and the given macro kind restriction.
123 /// Everything you need to know about a name's location to resolve it.
124 /// Serves as a starting point for the scope visitor.
125 /// This struct is currently used only for early resolution (imports and macros),
126 /// but not for late resolution yet.
127 #[derive(Clone, Copy, Debug)]
128 pub struct ParentScope<'a> {
131 legacy: LegacyScope<'a>,
132 derives: &'a [ast::Path],
135 impl<'a> ParentScope<'a> {
136 /// Creates a parent scope with the passed argument used as the module scope component,
137 /// and other scope components set to default empty values.
138 pub fn module(module: Module<'a>) -> ParentScope<'a> {
139 ParentScope { module, expansion: ExpnId::root(), legacy: LegacyScope::Empty, derives: &[] }
144 struct BindingError {
146 origin: BTreeSet<Span>,
147 target: BTreeSet<Span>,
151 impl PartialOrd for BindingError {
152 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
153 Some(self.cmp(other))
157 impl PartialEq for BindingError {
158 fn eq(&self, other: &BindingError) -> bool {
159 self.name == other.name
163 impl Ord for BindingError {
164 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
165 self.name.cmp(&other.name)
169 enum ResolutionError<'a> {
170 /// Error E0401: can't use type or const parameters from outer function.
171 GenericParamsFromOuterFunction(Res, HasGenericParams),
172 /// Error E0403: the name is already used for a type or const parameter in this generic
174 NameAlreadyUsedInParameterList(Name, Span),
175 /// Error E0407: method is not a member of trait.
176 MethodNotMemberOfTrait(Name, &'a str),
177 /// Error E0437: type is not a member of trait.
178 TypeNotMemberOfTrait(Name, &'a str),
179 /// Error E0438: const is not a member of trait.
180 ConstNotMemberOfTrait(Name, &'a str),
181 /// Error E0408: variable `{}` is not bound in all patterns.
182 VariableNotBoundInPattern(&'a BindingError),
183 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
184 VariableBoundWithDifferentMode(Name, Span),
185 /// Error E0415: identifier is bound more than once in this parameter list.
186 IdentifierBoundMoreThanOnceInParameterList(&'a str),
187 /// Error E0416: identifier is bound more than once in the same pattern.
188 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
189 /// Error E0426: use of undeclared label.
190 UndeclaredLabel(&'a str, Option<Name>),
191 /// Error E0429: `self` imports are only allowed within a `{ }` list.
192 SelfImportsOnlyAllowedWithin,
193 /// Error E0430: `self` import can only appear once in the list.
194 SelfImportCanOnlyAppearOnceInTheList,
195 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
196 SelfImportOnlyInImportListWithNonEmptyPrefix,
197 /// Error E0433: failed to resolve.
198 FailedToResolve { label: String, suggestion: Option<Suggestion> },
199 /// Error E0434: can't capture dynamic environment in a fn item.
200 CannotCaptureDynamicEnvironmentInFnItem,
201 /// Error E0435: attempt to use a non-constant value in a constant.
202 AttemptToUseNonConstantValueInConstant,
203 /// Error E0530: `X` bindings cannot shadow `Y`s.
204 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
205 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
206 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
207 /// Error E0735: type parameters with a default cannot use `Self`
208 SelfInTyParamDefault,
211 enum VisResolutionError<'a> {
212 Relative2018(Span, &'a ast::Path),
214 FailedToResolve(Span, String, Option<Suggestion>),
215 ExpectedFound(Span, String, Res),
220 // A minimal representation of a path segment. We use this in resolve because
221 // we synthesize 'path segments' which don't have the rest of an AST or HIR
223 #[derive(Clone, Copy, Debug)]
230 fn from_path(path: &Path) -> Vec<Segment> {
231 path.segments.iter().map(|s| s.into()).collect()
234 fn from_ident(ident: Ident) -> Segment {
235 Segment { ident, id: None }
238 fn names_to_string(segments: &[Segment]) -> String {
239 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
243 impl<'a> From<&'a ast::PathSegment> for Segment {
244 fn from(seg: &'a ast::PathSegment) -> Segment {
245 Segment { ident: seg.ident, id: Some(seg.id) }
249 struct UsePlacementFinder {
250 target_module: NodeId,
255 impl UsePlacementFinder {
256 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
257 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
258 visit::walk_crate(&mut finder, krate);
259 (finder.span, finder.found_use)
263 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
266 module: &'tcx ast::Mod,
268 _: &[ast::Attribute],
271 if self.span.is_some() {
274 if node_id != self.target_module {
275 visit::walk_mod(self, module);
278 // find a use statement
279 for item in &module.items {
281 ItemKind::Use(..) => {
282 // don't suggest placing a use before the prelude
283 // import or other generated ones
284 if !item.span.from_expansion() {
285 self.span = Some(item.span.shrink_to_lo());
286 self.found_use = true;
290 // don't place use before extern crate
291 ItemKind::ExternCrate(_) => {}
292 // but place them before the first other item
294 if self.span.map_or(true, |span| item.span < span) {
295 if !item.span.from_expansion() {
296 // don't insert between attributes and an item
297 if item.attrs.is_empty() {
298 self.span = Some(item.span.shrink_to_lo());
300 // find the first attribute on the item
301 for attr in &item.attrs {
302 if self.span.map_or(true, |span| attr.span < span) {
303 self.span = Some(attr.span.shrink_to_lo());
315 /// An intermediate resolution result.
317 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
318 /// items are visible in their whole block, while `Res`es only from the place they are defined
321 enum LexicalScopeBinding<'a> {
322 Item(&'a NameBinding<'a>),
326 impl<'a> LexicalScopeBinding<'a> {
327 fn item(self) -> Option<&'a NameBinding<'a>> {
329 LexicalScopeBinding::Item(binding) => Some(binding),
334 fn res(self) -> Res {
336 LexicalScopeBinding::Item(binding) => binding.res(),
337 LexicalScopeBinding::Res(res) => res,
342 #[derive(Copy, Clone, Debug)]
343 enum ModuleOrUniformRoot<'a> {
347 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
348 CrateRootAndExternPrelude,
350 /// Virtual module that denotes resolution in extern prelude.
351 /// Used for paths starting with `::` on 2018 edition.
354 /// Virtual module that denotes resolution in current scope.
355 /// Used only for resolving single-segment imports. The reason it exists is that import paths
356 /// are always split into two parts, the first of which should be some kind of module.
360 impl ModuleOrUniformRoot<'_> {
361 fn same_def(lhs: Self, rhs: Self) -> bool {
363 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
364 lhs.def_id() == rhs.def_id()
367 ModuleOrUniformRoot::CrateRootAndExternPrelude,
368 ModuleOrUniformRoot::CrateRootAndExternPrelude,
370 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
371 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
377 #[derive(Clone, Debug)]
378 enum PathResult<'a> {
379 Module(ModuleOrUniformRoot<'a>),
380 NonModule(PartialRes),
385 suggestion: Option<Suggestion>,
386 is_error_from_last_segment: bool,
391 /// An anonymous module; e.g., just a block.
396 /// { // This is an anonymous module
397 /// f(); // This resolves to (2) as we are inside the block.
400 /// f(); // Resolves to (1)
404 /// Any module with a name.
408 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
409 /// * A trait or an enum (it implicitly contains associated types, methods and variant
411 Def(DefKind, DefId, Name),
415 /// Get name of the module.
416 pub fn name(&self) -> Option<Name> {
418 ModuleKind::Block(..) => None,
419 ModuleKind::Def(.., name) => Some(*name),
424 /// A key that identifies a binding in a given `Module`.
426 /// Multiple bindings in the same module can have the same key (in a valid
427 /// program) if all but one of them come from glob imports.
428 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
430 /// The identifier for the binding, aways the `modern` version of the
434 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
435 /// `_` in the expanded AST that introduced this binding.
439 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
441 /// One node in the tree of modules.
442 pub struct ModuleData<'a> {
443 parent: Option<Module<'a>>,
446 // The def id of the closest normal module (`mod`) ancestor (including this module).
447 normal_ancestor_id: DefId,
449 // Mapping between names and their (possibly in-progress) resolutions in this module.
450 // Resolutions in modules from other crates are not populated until accessed.
451 lazy_resolutions: Resolutions<'a>,
452 // True if this is a module from other crate that needs to be populated on access.
453 populate_on_access: Cell<bool>,
455 // Macro invocations that can expand into items in this module.
456 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
458 no_implicit_prelude: bool,
460 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
461 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
463 // Used to memoize the traits in this module for faster searches through all traits in scope.
464 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
466 /// Span of the module itself. Used for error reporting.
472 type Module<'a> = &'a ModuleData<'a>;
474 impl<'a> ModuleData<'a> {
476 parent: Option<Module<'a>>,
478 normal_ancestor_id: DefId,
486 lazy_resolutions: Default::default(),
487 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
488 unexpanded_invocations: Default::default(),
489 no_implicit_prelude: false,
490 glob_importers: RefCell::new(Vec::new()),
491 globs: RefCell::new(Vec::new()),
492 traits: RefCell::new(None),
498 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
500 R: AsMut<Resolver<'a>>,
501 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
503 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
504 name_resolution.borrow().binding.map(|binding| f(resolver, key.ident, key.ns, binding));
508 fn res(&self) -> Option<Res> {
510 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
515 fn def_id(&self) -> Option<DefId> {
517 ModuleKind::Def(_, def_id, _) => Some(def_id),
522 // `self` resolves to the first module ancestor that `is_normal`.
523 fn is_normal(&self) -> bool {
525 ModuleKind::Def(DefKind::Mod, _, _) => true,
530 fn is_trait(&self) -> bool {
532 ModuleKind::Def(DefKind::Trait, _, _) => true,
537 fn nearest_item_scope(&'a self) -> Module<'a> {
539 ModuleKind::Def(DefKind::Enum, ..) | ModuleKind::Def(DefKind::Trait, ..) => {
540 self.parent.expect("enum or trait module without a parent")
546 fn is_ancestor_of(&self, mut other: &Self) -> bool {
547 while !ptr::eq(self, other) {
548 if let Some(parent) = other.parent {
558 impl<'a> fmt::Debug for ModuleData<'a> {
559 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
560 write!(f, "{:?}", self.res())
564 /// Records a possibly-private value, type, or module definition.
565 #[derive(Clone, Debug)]
566 pub struct NameBinding<'a> {
567 kind: NameBindingKind<'a>,
568 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
574 pub trait ToNameBinding<'a> {
575 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
578 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
579 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
584 #[derive(Clone, Debug)]
585 enum NameBindingKind<'a> {
586 Res(Res, /* is_macro_export */ bool),
588 Import { binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>, used: Cell<bool> },
591 impl<'a> NameBindingKind<'a> {
592 /// Is this a name binding of a import?
593 fn is_import(&self) -> bool {
595 NameBindingKind::Import { .. } => true,
601 struct PrivacyError<'a> {
603 binding: &'a NameBinding<'a>,
607 struct UseError<'a> {
608 err: DiagnosticBuilder<'a>,
609 /// Attach `use` statements for these candidates.
610 candidates: Vec<ImportSuggestion>,
611 /// The `NodeId` of the module to place the use-statements in.
613 /// Whether the diagnostic should state that it's "better".
615 /// Extra free form suggestion. Currently used to suggest new type parameter.
616 suggestion: Option<(Span, &'static str, String, Applicability)>,
619 #[derive(Clone, Copy, PartialEq, Debug)]
632 fn descr(self) -> &'static str {
634 AmbiguityKind::Import => "name vs any other name during import resolution",
635 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
636 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
637 AmbiguityKind::LegacyVsModern => "`macro_rules` vs non-`macro_rules` from other module",
638 AmbiguityKind::GlobVsOuter => {
639 "glob import vs any other name from outer scope during import/macro resolution"
641 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
642 AmbiguityKind::GlobVsExpanded => {
643 "glob import vs macro-expanded name in the same \
644 module during import/macro resolution"
646 AmbiguityKind::MoreExpandedVsOuter => {
647 "macro-expanded name vs less macro-expanded name \
648 from outer scope during import/macro resolution"
654 /// Miscellaneous bits of metadata for better ambiguity error reporting.
655 #[derive(Clone, Copy, PartialEq)]
656 enum AmbiguityErrorMisc {
663 struct AmbiguityError<'a> {
666 b1: &'a NameBinding<'a>,
667 b2: &'a NameBinding<'a>,
668 misc1: AmbiguityErrorMisc,
669 misc2: AmbiguityErrorMisc,
672 impl<'a> NameBinding<'a> {
673 fn module(&self) -> Option<Module<'a>> {
675 NameBindingKind::Module(module) => Some(module),
676 NameBindingKind::Import { binding, .. } => binding.module(),
681 fn res(&self) -> Res {
683 NameBindingKind::Res(res, _) => res,
684 NameBindingKind::Module(module) => module.res().unwrap(),
685 NameBindingKind::Import { binding, .. } => binding.res(),
689 fn is_ambiguity(&self) -> bool {
690 self.ambiguity.is_some()
692 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
697 // We sometimes need to treat variants as `pub` for backwards compatibility.
698 fn pseudo_vis(&self) -> ty::Visibility {
699 if self.is_variant() && self.res().def_id().is_local() {
700 ty::Visibility::Public
706 fn is_variant(&self) -> bool {
708 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _)
709 | NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
714 fn is_extern_crate(&self) -> bool {
716 NameBindingKind::Import {
718 &ImportDirective { subclass: ImportDirectiveSubclass::ExternCrate { .. }, .. },
721 NameBindingKind::Module(&ModuleData {
722 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
724 }) => def_id.index == CRATE_DEF_INDEX,
729 fn is_import(&self) -> bool {
731 NameBindingKind::Import { .. } => true,
736 fn is_glob_import(&self) -> bool {
738 NameBindingKind::Import { directive, .. } => directive.is_glob(),
743 fn is_importable(&self) -> bool {
745 Res::Def(DefKind::AssocConst, _)
746 | Res::Def(DefKind::Method, _)
747 | Res::Def(DefKind::AssocTy, _) => false,
752 fn is_macro_def(&self) -> bool {
754 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
759 fn macro_kind(&self) -> Option<MacroKind> {
760 self.res().macro_kind()
763 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
764 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
765 // Then this function returns `true` if `self` may emerge from a macro *after* that
766 // in some later round and screw up our previously found resolution.
767 // See more detailed explanation in
768 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
769 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
770 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
771 // Expansions are partially ordered, so "may appear after" is an inversion of
772 // "certainly appears before or simultaneously" and includes unordered cases.
773 let self_parent_expansion = self.expansion;
774 let other_parent_expansion = binding.expansion;
775 let certainly_before_other_or_simultaneously =
776 other_parent_expansion.is_descendant_of(self_parent_expansion);
777 let certainly_before_invoc_or_simultaneously =
778 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
779 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
783 /// Interns the names of the primitive types.
785 /// All other types are defined somewhere and possibly imported, but the primitive ones need
786 /// special handling, since they have no place of origin.
787 struct PrimitiveTypeTable {
788 primitive_types: FxHashMap<Name, PrimTy>,
791 impl PrimitiveTypeTable {
792 fn new() -> PrimitiveTypeTable {
793 let mut table = FxHashMap::default();
795 table.insert(sym::bool, Bool);
796 table.insert(sym::char, Char);
797 table.insert(sym::f32, Float(FloatTy::F32));
798 table.insert(sym::f64, Float(FloatTy::F64));
799 table.insert(sym::isize, Int(IntTy::Isize));
800 table.insert(sym::i8, Int(IntTy::I8));
801 table.insert(sym::i16, Int(IntTy::I16));
802 table.insert(sym::i32, Int(IntTy::I32));
803 table.insert(sym::i64, Int(IntTy::I64));
804 table.insert(sym::i128, Int(IntTy::I128));
805 table.insert(sym::str, Str);
806 table.insert(sym::usize, Uint(UintTy::Usize));
807 table.insert(sym::u8, Uint(UintTy::U8));
808 table.insert(sym::u16, Uint(UintTy::U16));
809 table.insert(sym::u32, Uint(UintTy::U32));
810 table.insert(sym::u64, Uint(UintTy::U64));
811 table.insert(sym::u128, Uint(UintTy::U128));
812 Self { primitive_types: table }
816 #[derive(Debug, Default, Clone)]
817 pub struct ExternPreludeEntry<'a> {
818 extern_crate_item: Option<&'a NameBinding<'a>>,
819 pub introduced_by_item: bool,
822 /// The main resolver class.
824 /// This is the visitor that walks the whole crate.
825 pub struct Resolver<'a> {
826 session: &'a Session,
828 definitions: Definitions,
830 graph_root: Module<'a>,
832 prelude: Option<Module<'a>>,
833 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
835 /// N.B., this is used only for better diagnostics, not name resolution itself.
836 has_self: FxHashSet<DefId>,
838 /// Names of fields of an item `DefId` accessible with dot syntax.
839 /// Used for hints during error reporting.
840 field_names: FxHashMap<DefId, Vec<Spanned<Name>>>,
842 /// All imports known to succeed or fail.
843 determined_imports: Vec<&'a ImportDirective<'a>>,
845 /// All non-determined imports.
846 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
848 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
849 /// We are resolving a last import segment during import validation.
850 last_import_segment: bool,
851 /// This binding should be ignored during in-module resolution, so that we don't get
852 /// "self-confirming" import resolutions during import validation.
853 blacklisted_binding: Option<&'a NameBinding<'a>>,
855 /// The idents for the primitive types.
856 primitive_type_table: PrimitiveTypeTable,
858 /// Resolutions for nodes that have a single resolution.
859 partial_res_map: NodeMap<PartialRes>,
860 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
861 import_res_map: NodeMap<PerNS<Option<Res>>>,
862 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
863 label_res_map: NodeMap<NodeId>,
865 /// `CrateNum` resolutions of `extern crate` items.
866 extern_crate_map: NodeMap<CrateNum>,
867 export_map: ExportMap<NodeId>,
870 /// A map from nodes to anonymous modules.
871 /// Anonymous modules are pseudo-modules that are implicitly created around items
872 /// contained within blocks.
874 /// For example, if we have this:
882 /// There will be an anonymous module created around `g` with the ID of the
883 /// entry block for `f`.
884 block_map: NodeMap<Module<'a>>,
885 /// A fake module that contains no definition and no prelude. Used so that
886 /// some AST passes can generate identifiers that only resolve to local or
888 empty_module: Module<'a>,
889 module_map: FxHashMap<DefId, Module<'a>>,
890 extern_module_map: FxHashMap<DefId, Module<'a>>,
891 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
892 underscore_disambiguator: u32,
894 /// Maps glob imports to the names of items actually imported.
897 used_imports: FxHashSet<(NodeId, Namespace)>,
898 maybe_unused_trait_imports: NodeSet,
899 maybe_unused_extern_crates: Vec<(NodeId, Span)>,
901 /// Privacy errors are delayed until the end in order to deduplicate them.
902 privacy_errors: Vec<PrivacyError<'a>>,
903 /// Ambiguity errors are delayed for deduplication.
904 ambiguity_errors: Vec<AmbiguityError<'a>>,
905 /// `use` injections are delayed for better placement and deduplication.
906 use_injections: Vec<UseError<'a>>,
907 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
908 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
910 arenas: &'a ResolverArenas<'a>,
911 dummy_binding: &'a NameBinding<'a>,
913 crate_loader: CrateLoader<'a>,
914 macro_names: FxHashSet<Ident>,
915 builtin_macros: FxHashMap<Name, SyntaxExtension>,
916 registered_attrs: FxHashSet<Ident>,
917 registered_tools: FxHashSet<Ident>,
918 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
919 all_macros: FxHashMap<Name, Res>,
920 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
921 dummy_ext_bang: Lrc<SyntaxExtension>,
922 dummy_ext_derive: Lrc<SyntaxExtension>,
923 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
924 macro_defs: FxHashMap<ExpnId, DefId>,
925 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
926 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
927 unused_macros: NodeMap<Span>,
928 proc_macro_stubs: NodeSet,
929 /// Traces collected during macro resolution and validated when it's complete.
930 single_segment_macro_resolutions:
931 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
932 multi_segment_macro_resolutions:
933 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
934 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
935 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
936 /// Derive macros cannot modify the item themselves and have to store the markers in the global
937 /// context, so they attach the markers to derive container IDs using this resolver table.
938 containers_deriving_copy: FxHashSet<ExpnId>,
939 /// Parent scopes in which the macros were invoked.
940 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
941 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
942 /// Legacy scopes *produced* by expanding the macro invocations,
943 /// include all the `macro_rules` items and other invocations generated by them.
944 output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
945 /// Helper attributes that are in scope for the given expansion.
946 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
948 /// Avoid duplicated errors for "name already defined".
949 name_already_seen: FxHashMap<Name, Span>,
951 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
953 /// Table for mapping struct IDs into struct constructor IDs,
954 /// it's not used during normal resolution, only for better error reporting.
955 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
957 /// Features enabled for this crate.
958 active_features: FxHashSet<Name>,
960 /// Stores enum visibilities to properly build a reduced graph
961 /// when visiting the correspondent variants.
962 variant_vis: DefIdMap<ty::Visibility>,
964 lint_buffer: LintBuffer,
966 next_node_id: NodeId,
969 /// Nothing really interesting here; it just provides memory for the rest of the crate.
971 pub struct ResolverArenas<'a> {
972 modules: arena::TypedArena<ModuleData<'a>>,
973 local_modules: RefCell<Vec<Module<'a>>>,
974 name_bindings: arena::TypedArena<NameBinding<'a>>,
975 import_directives: arena::TypedArena<ImportDirective<'a>>,
976 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
977 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
978 ast_paths: arena::TypedArena<ast::Path>,
981 impl<'a> ResolverArenas<'a> {
982 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
983 let module = self.modules.alloc(module);
984 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
985 self.local_modules.borrow_mut().push(module);
989 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
990 self.local_modules.borrow()
992 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
993 self.name_bindings.alloc(name_binding)
995 fn alloc_import_directive(
997 import_directive: ImportDirective<'a>,
998 ) -> &'a ImportDirective<'_> {
999 self.import_directives.alloc(import_directive)
1001 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1002 self.name_resolutions.alloc(Default::default())
1004 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1005 self.legacy_bindings.alloc(binding)
1007 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1008 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1012 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1013 fn as_mut(&mut self) -> &mut Resolver<'a> {
1018 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1019 fn parent(self, id: DefId) -> Option<DefId> {
1021 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1022 _ => self.cstore().def_key(id).parent,
1024 .map(|index| DefId { index, ..id })
1028 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1029 /// the resolver is no longer needed as all the relevant information is inline.
1030 impl rustc_ast_lowering::Resolver for Resolver<'_> {
1031 fn def_key(&mut self, id: DefId) -> DefKey {
1032 if id.is_local() { self.definitions().def_key(id.index) } else { self.cstore().def_key(id) }
1035 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1036 self.cstore().item_generics_num_lifetimes(def_id, sess)
1039 fn resolve_str_path(
1042 crate_root: Option<Name>,
1043 components: &[Name],
1045 ) -> (ast::Path, Res) {
1046 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1047 let segments = iter::once(Ident::with_dummy_span(root))
1051 .chain(components.iter().cloned())
1052 .map(Ident::with_dummy_span),
1054 .map(|i| self.new_ast_path_segment(i))
1055 .collect::<Vec<_>>();
1057 let path = ast::Path { span, segments };
1059 let parent_scope = &ParentScope::module(self.graph_root);
1060 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1062 Err((span, error)) => {
1063 self.report_error(span, error);
1070 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1071 self.partial_res_map.get(&id).cloned()
1074 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1075 self.import_res_map.get(&id).cloned().unwrap_or_default()
1078 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1079 self.label_res_map.get(&id).cloned()
1082 fn definitions(&mut self) -> &mut Definitions {
1083 &mut self.definitions
1086 fn lint_buffer(&mut self) -> &mut LintBuffer {
1087 &mut self.lint_buffer
1090 fn next_node_id(&mut self) -> NodeId {
1095 impl<'a> Resolver<'a> {
1097 session: &'a Session,
1100 metadata_loader: &'a MetadataLoaderDyn,
1101 arenas: &'a ResolverArenas<'a>,
1103 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1104 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1105 let graph_root = arenas.alloc_module(ModuleData {
1106 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1107 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1109 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1110 let empty_module = arenas.alloc_module(ModuleData {
1111 no_implicit_prelude: true,
1120 let mut module_map = FxHashMap::default();
1121 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1123 let mut definitions = Definitions::default();
1124 definitions.create_root_def(crate_name, session.local_crate_disambiguator());
1126 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1130 .filter(|(_, entry)| entry.add_prelude)
1131 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1134 if !attr::contains_name(&krate.attrs, sym::no_core) {
1135 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1136 if !attr::contains_name(&krate.attrs, sym::no_std) {
1137 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1138 if session.rust_2018() {
1139 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1144 let (registered_attrs, registered_tools) =
1145 macros::registered_attrs_and_tools(session, &krate.attrs);
1147 let mut invocation_parent_scopes = FxHashMap::default();
1148 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1150 let mut macro_defs = FxHashMap::default();
1151 macro_defs.insert(ExpnId::root(), root_def_id);
1153 let features = session.features_untracked();
1154 let non_macro_attr =
1155 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1162 // The outermost module has def ID 0; this is not reflected in the
1168 has_self: FxHashSet::default(),
1169 field_names: FxHashMap::default(),
1171 determined_imports: Vec::new(),
1172 indeterminate_imports: Vec::new(),
1174 last_import_segment: false,
1175 blacklisted_binding: None,
1177 primitive_type_table: PrimitiveTypeTable::new(),
1179 partial_res_map: Default::default(),
1180 import_res_map: Default::default(),
1181 label_res_map: Default::default(),
1182 extern_crate_map: Default::default(),
1183 export_map: FxHashMap::default(),
1184 trait_map: Default::default(),
1185 underscore_disambiguator: 0,
1188 block_map: Default::default(),
1189 extern_module_map: FxHashMap::default(),
1190 binding_parent_modules: FxHashMap::default(),
1191 ast_transform_scopes: FxHashMap::default(),
1193 glob_map: Default::default(),
1195 used_imports: FxHashSet::default(),
1196 maybe_unused_trait_imports: Default::default(),
1197 maybe_unused_extern_crates: Vec::new(),
1199 privacy_errors: Vec::new(),
1200 ambiguity_errors: Vec::new(),
1201 use_injections: Vec::new(),
1202 macro_expanded_macro_export_errors: BTreeSet::new(),
1205 dummy_binding: arenas.alloc_name_binding(NameBinding {
1206 kind: NameBindingKind::Res(Res::Err, false),
1208 expansion: ExpnId::root(),
1210 vis: ty::Visibility::Public,
1213 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1214 macro_names: FxHashSet::default(),
1215 builtin_macros: Default::default(),
1218 macro_use_prelude: FxHashMap::default(),
1219 all_macros: FxHashMap::default(),
1220 macro_map: FxHashMap::default(),
1221 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1222 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1223 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1224 invocation_parent_scopes,
1225 output_legacy_scopes: Default::default(),
1226 helper_attrs: Default::default(),
1228 local_macro_def_scopes: FxHashMap::default(),
1229 name_already_seen: FxHashMap::default(),
1230 potentially_unused_imports: Vec::new(),
1231 struct_constructors: Default::default(),
1232 unused_macros: Default::default(),
1233 proc_macro_stubs: Default::default(),
1234 single_segment_macro_resolutions: Default::default(),
1235 multi_segment_macro_resolutions: Default::default(),
1236 builtin_attrs: Default::default(),
1237 containers_deriving_copy: Default::default(),
1238 active_features: features
1239 .declared_lib_features
1241 .map(|(feat, ..)| *feat)
1242 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1244 variant_vis: Default::default(),
1245 lint_buffer: LintBuffer::default(),
1246 next_node_id: NodeId::from_u32(1),
1250 pub fn next_node_id(&mut self) -> NodeId {
1255 .expect("input too large; ran out of NodeIds");
1256 self.next_node_id = ast::NodeId::from_usize(next);
1260 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1261 &mut self.lint_buffer
1264 pub fn arenas() -> ResolverArenas<'a> {
1268 pub fn into_outputs(self) -> ResolverOutputs {
1270 definitions: self.definitions,
1271 cstore: Box::new(self.crate_loader.into_cstore()),
1272 extern_crate_map: self.extern_crate_map,
1273 export_map: self.export_map,
1274 trait_map: self.trait_map,
1275 glob_map: self.glob_map,
1276 maybe_unused_trait_imports: self.maybe_unused_trait_imports,
1277 maybe_unused_extern_crates: self.maybe_unused_extern_crates,
1278 extern_prelude: self
1281 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1286 pub fn clone_outputs(&self) -> ResolverOutputs {
1288 definitions: self.definitions.clone(),
1289 cstore: Box::new(self.cstore().clone()),
1290 extern_crate_map: self.extern_crate_map.clone(),
1291 export_map: self.export_map.clone(),
1292 trait_map: self.trait_map.clone(),
1293 glob_map: self.glob_map.clone(),
1294 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1295 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1296 extern_prelude: self
1299 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1304 pub fn cstore(&self) -> &CStore {
1305 self.crate_loader.cstore()
1308 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1309 self.non_macro_attrs[mark_used as usize].clone()
1312 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1314 MacroKind::Bang => self.dummy_ext_bang.clone(),
1315 MacroKind::Derive => self.dummy_ext_derive.clone(),
1316 MacroKind::Attr => self.non_macro_attr(true),
1320 /// Runs the function on each namespace.
1321 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1327 fn is_builtin_macro(&mut self, res: Res) -> bool {
1328 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1331 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1333 match self.macro_defs.get(&ctxt.outer_expn()) {
1334 Some(&def_id) => return def_id,
1335 None => ctxt.remove_mark(),
1340 /// Entry point to crate resolution.
1341 pub fn resolve_crate(&mut self, krate: &Crate) {
1342 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1344 ImportResolver { r: self }.finalize_imports();
1345 self.finalize_macro_resolutions();
1347 self.late_resolve_crate(krate);
1349 self.check_unused(krate);
1350 self.report_errors(krate);
1351 self.crate_loader.postprocess(krate);
1358 normal_ancestor_id: DefId,
1362 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1363 self.arenas.alloc_module(module)
1366 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1367 let ident = ident.modern();
1368 let disambiguator = if ident.name == kw::Underscore {
1369 self.underscore_disambiguator += 1;
1370 self.underscore_disambiguator
1374 BindingKey { ident, ns, disambiguator }
1377 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1378 if module.populate_on_access.get() {
1379 module.populate_on_access.set(false);
1380 self.build_reduced_graph_external(module);
1382 &module.lazy_resolutions
1389 ) -> &'a RefCell<NameResolution<'a>> {
1391 .resolutions(module)
1394 .or_insert_with(|| self.arenas.alloc_name_resolution())
1401 used_binding: &'a NameBinding<'a>,
1402 is_lexical_scope: bool,
1404 if let Some((b2, kind)) = used_binding.ambiguity {
1405 self.ambiguity_errors.push(AmbiguityError {
1410 misc1: AmbiguityErrorMisc::None,
1411 misc2: AmbiguityErrorMisc::None,
1414 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1415 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1416 // but not introduce it, as used if they are accessed from lexical scope.
1417 if is_lexical_scope {
1418 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1419 if let Some(crate_item) = entry.extern_crate_item {
1420 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1427 directive.used.set(true);
1428 self.used_imports.insert((directive.id, ns));
1429 self.add_to_glob_map(&directive, ident);
1430 self.record_use(ident, ns, binding, false);
1435 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
1436 if directive.is_glob() {
1437 self.glob_map.entry(directive.id).or_default().insert(ident.name);
1441 /// A generic scope visitor.
1442 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1443 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1446 scope_set: ScopeSet,
1447 parent_scope: &ParentScope<'a>,
1449 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1451 // General principles:
1452 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1453 // built into the language or standard library. This way we can add new names into the
1454 // language or standard library without breaking user code.
1455 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1456 // Places to search (in order of decreasing priority):
1458 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1459 // (open set, not controlled).
1460 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1461 // (open, not controlled).
1462 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1463 // 4. Tool modules (closed, controlled right now, but not in the future).
1464 // 5. Standard library prelude (de-facto closed, controlled).
1465 // 6. Language prelude (closed, controlled).
1467 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1468 // (open set, not controlled).
1469 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1470 // (open, not controlled).
1471 // 3. Standard library prelude (de-facto closed, controlled).
1473 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1474 // are currently reported as errors. They should be higher in priority than preludes
1475 // and probably even names in modules according to the "general principles" above. They
1476 // also should be subject to restricted shadowing because are effectively produced by
1477 // derives (you need to resolve the derive first to add helpers into scope), but they
1478 // should be available before the derive is expanded for compatibility.
1479 // It's mess in general, so we are being conservative for now.
1480 // 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
1481 // priority than prelude macros, but create ambiguities with macros in modules.
1482 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1483 // (open, not controlled). Have higher priority than prelude macros, but create
1484 // ambiguities with `macro_rules`.
1485 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1486 // 4a. User-defined prelude from macro-use
1487 // (open, the open part is from macro expansions, not controlled).
1488 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1489 // 4c. Standard library prelude (de-facto closed, controlled).
1490 // 6. Language prelude: builtin attributes (closed, controlled).
1492 let rust_2015 = ident.span.rust_2015();
1493 let (ns, macro_kind, is_absolute_path) = match scope_set {
1494 ScopeSet::All(ns, _) => (ns, None, false),
1495 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1496 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1498 // Jump out of trait or enum modules, they do not act as scopes.
1499 let module = parent_scope.module.nearest_item_scope();
1500 let mut scope = match ns {
1501 _ if is_absolute_path => Scope::CrateRoot,
1502 TypeNS | ValueNS => Scope::Module(module),
1503 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1505 let mut ident = ident.modern();
1506 let mut use_prelude = !module.no_implicit_prelude;
1509 let visit = match scope {
1510 // Derive helpers are not in scope when resolving derives in the same container.
1511 Scope::DeriveHelpers(expn_id) => {
1512 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1514 Scope::DeriveHelpersCompat => true,
1515 Scope::MacroRules(..) => true,
1516 Scope::CrateRoot => true,
1517 Scope::Module(..) => true,
1518 Scope::RegisteredAttrs => use_prelude,
1519 Scope::MacroUsePrelude => use_prelude || rust_2015,
1520 Scope::BuiltinAttrs => true,
1521 Scope::ExternPrelude => use_prelude || is_absolute_path,
1522 Scope::ToolPrelude => use_prelude,
1523 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1524 Scope::BuiltinTypes => true,
1528 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1529 return break_result;
1533 scope = match scope {
1534 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1535 // Derive helpers are not visible to code generated by bang or derive macros.
1536 let expn_data = expn_id.expn_data();
1537 match expn_data.kind {
1539 | ExpnKind::Macro(MacroKind::Bang, _)
1540 | ExpnKind::Macro(MacroKind::Derive, _) => Scope::DeriveHelpersCompat,
1541 _ => Scope::DeriveHelpers(expn_data.parent),
1544 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1545 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.legacy),
1546 Scope::MacroRules(legacy_scope) => match legacy_scope {
1547 LegacyScope::Binding(binding) => Scope::MacroRules(binding.parent_legacy_scope),
1548 LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
1549 self.output_legacy_scopes
1552 .unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy),
1554 LegacyScope::Empty => Scope::Module(module),
1556 Scope::CrateRoot => match ns {
1558 ident.span.adjust(ExpnId::root());
1559 Scope::ExternPrelude
1561 ValueNS | MacroNS => break,
1563 Scope::Module(module) => {
1564 use_prelude = !module.no_implicit_prelude;
1565 match self.hygienic_lexical_parent(module, &mut ident.span) {
1566 Some(parent_module) => Scope::Module(parent_module),
1568 ident.span.adjust(ExpnId::root());
1570 TypeNS => Scope::ExternPrelude,
1571 ValueNS => Scope::StdLibPrelude,
1572 MacroNS => Scope::RegisteredAttrs,
1577 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1578 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1579 Scope::BuiltinAttrs => break, // nowhere else to search
1580 Scope::ExternPrelude if is_absolute_path => break,
1581 Scope::ExternPrelude => Scope::ToolPrelude,
1582 Scope::ToolPrelude => Scope::StdLibPrelude,
1583 Scope::StdLibPrelude => match ns {
1584 TypeNS => Scope::BuiltinTypes,
1585 ValueNS => break, // nowhere else to search
1586 MacroNS => Scope::BuiltinAttrs,
1588 Scope::BuiltinTypes => break, // nowhere else to search
1595 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1596 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1597 /// `ident` in the first scope that defines it (or None if no scopes define it).
1599 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1600 /// the items are defined in the block. For example,
1603 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1606 /// g(); // This resolves to the local variable `g` since it shadows the item.
1610 /// Invariant: This must only be called during main resolution, not during
1611 /// import resolution.
1612 fn resolve_ident_in_lexical_scope(
1616 parent_scope: &ParentScope<'a>,
1617 record_used_id: Option<NodeId>,
1620 ) -> Option<LexicalScopeBinding<'a>> {
1621 assert!(ns == TypeNS || ns == ValueNS);
1622 if ident.name == kw::Invalid {
1623 return Some(LexicalScopeBinding::Res(Res::Err));
1625 let (general_span, modern_span) = if ident.name == kw::SelfUpper {
1626 // FIXME(jseyfried) improve `Self` hygiene
1627 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1628 (empty_span, empty_span)
1629 } else if ns == TypeNS {
1630 let modern_span = ident.span.modern();
1631 (modern_span, modern_span)
1633 (ident.span.modern_and_legacy(), ident.span.modern())
1635 ident.span = general_span;
1636 let modern_ident = Ident { span: modern_span, ..ident };
1638 // Walk backwards up the ribs in scope.
1639 let record_used = record_used_id.is_some();
1640 let mut module = self.graph_root;
1641 for i in (0..ribs.len()).rev() {
1642 debug!("walk rib\n{:?}", ribs[i].bindings);
1643 // Use the rib kind to determine whether we are resolving parameters
1644 // (modern hygiene) or local variables (legacy hygiene).
1645 let rib_ident = if ribs[i].kind.contains_params() { modern_ident } else { ident };
1646 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1647 // The ident resolves to a type parameter or local variable.
1648 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1658 module = match ribs[i].kind {
1659 ModuleRibKind(module) => module,
1660 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1661 // If an invocation of this macro created `ident`, give up on `ident`
1662 // and switch to `ident`'s source from the macro definition.
1663 ident.span.remove_mark();
1669 let item = self.resolve_ident_in_module_unadjusted(
1670 ModuleOrUniformRoot::Module(module),
1677 if let Ok(binding) = item {
1678 // The ident resolves to an item.
1679 return Some(LexicalScopeBinding::Item(binding));
1683 ModuleKind::Block(..) => {} // We can see through blocks
1688 ident = modern_ident;
1689 let mut poisoned = None;
1691 let opt_module = if let Some(node_id) = record_used_id {
1692 self.hygienic_lexical_parent_with_compatibility_fallback(
1699 self.hygienic_lexical_parent(module, &mut ident.span)
1701 module = unwrap_or!(opt_module, break);
1702 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1703 let result = self.resolve_ident_in_module_unadjusted(
1704 ModuleOrUniformRoot::Module(module),
1707 adjusted_parent_scope,
1714 if let Some(node_id) = poisoned {
1715 self.lint_buffer.buffer_lint_with_diagnostic(
1716 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1719 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1720 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1723 return Some(LexicalScopeBinding::Item(binding));
1725 Err(Determined) => continue,
1726 Err(Undetermined) => {
1727 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1732 if !module.no_implicit_prelude {
1733 ident.span.adjust(ExpnId::root());
1735 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1736 return Some(LexicalScopeBinding::Item(binding));
1738 if let Some(ident) = self.registered_tools.get(&ident) {
1740 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1741 .to_name_binding(self.arenas);
1742 return Some(LexicalScopeBinding::Item(binding));
1745 if let Some(prelude) = self.prelude {
1746 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1747 ModuleOrUniformRoot::Module(prelude),
1754 return Some(LexicalScopeBinding::Item(binding));
1760 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1762 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1763 .to_name_binding(self.arenas);
1764 return Some(LexicalScopeBinding::Item(binding));
1771 fn hygienic_lexical_parent(
1775 ) -> Option<Module<'a>> {
1776 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1777 return Some(self.macro_def_scope(span.remove_mark()));
1780 if let ModuleKind::Block(..) = module.kind {
1781 return Some(module.parent.unwrap().nearest_item_scope());
1787 fn hygienic_lexical_parent_with_compatibility_fallback(
1792 poisoned: &mut Option<NodeId>,
1793 ) -> Option<Module<'a>> {
1794 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1798 // We need to support the next case under a deprecation warning
1801 // ---- begin: this comes from a proc macro derive
1802 // mod implementation_details {
1803 // // Note that `MyStruct` is not in scope here.
1804 // impl SomeTrait for MyStruct { ... }
1808 // So we have to fall back to the module's parent during lexical resolution in this case.
1809 if let Some(parent) = module.parent {
1810 // Inner module is inside the macro, parent module is outside of the macro.
1811 if module.expansion != parent.expansion
1812 && module.expansion.is_descendant_of(parent.expansion)
1814 // The macro is a proc macro derive
1815 if let Some(&def_id) = self.macro_defs.get(&module.expansion) {
1816 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1817 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1818 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1819 *poisoned = Some(node_id);
1820 return module.parent;
1831 fn resolve_ident_in_module(
1833 module: ModuleOrUniformRoot<'a>,
1836 parent_scope: &ParentScope<'a>,
1839 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1840 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1841 .map_err(|(determinacy, _)| determinacy)
1844 fn resolve_ident_in_module_ext(
1846 module: ModuleOrUniformRoot<'a>,
1849 parent_scope: &ParentScope<'a>,
1852 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1853 let tmp_parent_scope;
1854 let mut adjusted_parent_scope = parent_scope;
1856 ModuleOrUniformRoot::Module(m) => {
1857 if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
1859 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1860 adjusted_parent_scope = &tmp_parent_scope;
1863 ModuleOrUniformRoot::ExternPrelude => {
1864 ident.span.modernize_and_adjust(ExpnId::root());
1866 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1870 let result = self.resolve_ident_in_module_unadjusted_ext(
1874 adjusted_parent_scope,
1882 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1883 let mut ctxt = ident.span.ctxt();
1884 let mark = if ident.name == kw::DollarCrate {
1885 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1886 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1887 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
1888 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
1889 // definitions actually produced by `macro` and `macro` definitions produced by
1890 // `macro_rules!`, but at least such configurations are not stable yet.
1891 ctxt = ctxt.modern_and_legacy();
1892 let mut iter = ctxt.marks().into_iter().rev().peekable();
1893 let mut result = None;
1894 // Find the last modern mark from the end if it exists.
1895 while let Some(&(mark, transparency)) = iter.peek() {
1896 if transparency == Transparency::Opaque {
1897 result = Some(mark);
1903 // Then find the last legacy mark from the end if it exists.
1904 for (mark, transparency) in iter {
1905 if transparency == Transparency::SemiTransparent {
1906 result = Some(mark);
1913 ctxt = ctxt.modern();
1914 ctxt.adjust(ExpnId::root())
1916 let module = match mark {
1917 Some(def) => self.macro_def_scope(def),
1918 None => return self.graph_root,
1920 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1923 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1924 let mut module = self.get_module(module.normal_ancestor_id);
1925 while module.span.ctxt().modern() != *ctxt {
1926 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1927 module = self.get_module(parent.normal_ancestor_id);
1935 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1936 parent_scope: &ParentScope<'a>,
1939 crate_lint: CrateLint,
1940 ) -> PathResult<'a> {
1941 self.resolve_path_with_ribs(
1952 fn resolve_path_with_ribs(
1955 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1956 parent_scope: &ParentScope<'a>,
1959 crate_lint: CrateLint,
1960 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1961 ) -> PathResult<'a> {
1962 let mut module = None;
1963 let mut allow_super = true;
1964 let mut second_binding = None;
1967 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
1968 path_span={:?}, crate_lint={:?})",
1969 path, opt_ns, record_used, path_span, crate_lint,
1972 for (i, &Segment { ident, id }) in path.iter().enumerate() {
1973 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
1974 let record_segment_res = |this: &mut Self, res| {
1976 if let Some(id) = id {
1977 if !this.partial_res_map.contains_key(&id) {
1978 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
1979 this.record_partial_res(id, PartialRes::new(res));
1985 let is_last = i == path.len() - 1;
1986 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1987 let name = ident.name;
1989 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
1992 if allow_super && name == kw::Super {
1993 let mut ctxt = ident.span.ctxt().modern();
1994 let self_module = match i {
1995 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
1997 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2001 if let Some(self_module) = self_module {
2002 if let Some(parent) = self_module.parent {
2003 module = Some(ModuleOrUniformRoot::Module(
2004 self.resolve_self(&mut ctxt, parent),
2009 let msg = "there are too many leading `super` keywords".to_string();
2010 return PathResult::Failed {
2014 is_error_from_last_segment: false,
2018 if name == kw::SelfLower {
2019 let mut ctxt = ident.span.ctxt().modern();
2020 module = Some(ModuleOrUniformRoot::Module(
2021 self.resolve_self(&mut ctxt, parent_scope.module),
2025 if name == kw::PathRoot && ident.span.rust_2018() {
2026 module = Some(ModuleOrUniformRoot::ExternPrelude);
2029 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2030 // `::a::b` from 2015 macro on 2018 global edition
2031 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2034 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2035 // `::a::b`, `crate::a::b` or `$crate::a::b`
2036 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2042 // Report special messages for path segment keywords in wrong positions.
2043 if ident.is_path_segment_keyword() && i != 0 {
2044 let name_str = if name == kw::PathRoot {
2045 "crate root".to_string()
2047 format!("`{}`", name)
2049 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2050 format!("global paths cannot start with {}", name_str)
2052 format!("{} in paths can only be used in start position", name_str)
2054 return PathResult::Failed {
2058 is_error_from_last_segment: false,
2062 let binding = if let Some(module) = module {
2063 self.resolve_ident_in_module(
2071 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2072 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2073 self.early_resolve_ident_in_lexical_scope(
2082 let record_used_id =
2083 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
2084 match self.resolve_ident_in_lexical_scope(
2092 // we found a locally-imported or available item/module
2093 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2094 // we found a local variable or type param
2095 Some(LexicalScopeBinding::Res(res))
2096 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2098 record_segment_res(self, res);
2099 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2104 _ => Err(Determinacy::determined(record_used)),
2111 second_binding = Some(binding);
2113 let res = binding.res();
2114 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2115 if let Some(next_module) = binding.module() {
2116 module = Some(ModuleOrUniformRoot::Module(next_module));
2117 record_segment_res(self, res);
2118 } else if res == Res::ToolMod && i + 1 != path.len() {
2119 if binding.is_import() {
2123 "cannot use a tool module through an import",
2125 .span_note(binding.span, "the tool module imported here")
2128 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2129 return PathResult::NonModule(PartialRes::new(res));
2130 } else if res == Res::Err {
2131 return PathResult::NonModule(PartialRes::new(Res::Err));
2132 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2133 self.lint_if_path_starts_with_module(
2139 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2144 let label = format!(
2145 "`{}` is {} {}, not a module",
2151 return PathResult::Failed {
2155 is_error_from_last_segment: is_last,
2159 Err(Undetermined) => return PathResult::Indeterminate,
2160 Err(Determined) => {
2161 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2162 if opt_ns.is_some() && !module.is_normal() {
2163 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2164 module.res().unwrap(),
2169 let module_res = match module {
2170 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2173 let (label, suggestion) = if module_res == self.graph_root.res() {
2174 let is_mod = |res| match res {
2175 Res::Def(DefKind::Mod, _) => true,
2178 let mut candidates = self.lookup_import_candidates(ident, TypeNS, is_mod);
2179 candidates.sort_by_cached_key(|c| {
2180 (c.path.segments.len(), pprust::path_to_string(&c.path))
2182 if let Some(candidate) = candidates.get(0) {
2184 String::from("unresolved import"),
2186 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2187 String::from("a similar path exists"),
2188 Applicability::MaybeIncorrect,
2191 } else if !ident.is_reserved() {
2192 (format!("maybe a missing crate `{}`?", ident), None)
2194 // the parser will already have complained about the keyword being used
2195 return PathResult::NonModule(PartialRes::new(Res::Err));
2198 (format!("use of undeclared type or module `{}`", ident), None)
2200 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
2202 return PathResult::Failed {
2206 is_error_from_last_segment: is_last,
2212 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2214 PathResult::Module(match module {
2215 Some(module) => module,
2216 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2217 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2221 fn lint_if_path_starts_with_module(
2223 crate_lint: CrateLint,
2226 second_binding: Option<&NameBinding<'_>>,
2228 let (diag_id, diag_span) = match crate_lint {
2229 CrateLint::No => return,
2230 CrateLint::SimplePath(id) => (id, path_span),
2231 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2232 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2235 let first_name = match path.get(0) {
2236 // In the 2018 edition this lint is a hard error, so nothing to do
2237 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2241 // We're only interested in `use` paths which should start with
2242 // `{{root}}` currently.
2243 if first_name != kw::PathRoot {
2248 // If this import looks like `crate::...` it's already good
2249 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2250 // Otherwise go below to see if it's an extern crate
2252 // If the path has length one (and it's `PathRoot` most likely)
2253 // then we don't know whether we're gonna be importing a crate or an
2254 // item in our crate. Defer this lint to elsewhere
2258 // If the first element of our path was actually resolved to an
2259 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2260 // warning, this looks all good!
2261 if let Some(binding) = second_binding {
2262 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
2263 // Careful: we still want to rewrite paths from
2264 // renamed extern crates.
2265 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
2271 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2272 self.lint_buffer.buffer_lint_with_diagnostic(
2273 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2276 "absolute paths must start with `self`, `super`, \
2277 `crate`, or an external crate name in the 2018 edition",
2282 // Validate a local resolution (from ribs).
2283 fn validate_res_from_ribs(
2290 all_ribs: &[Rib<'a>],
2292 debug!("validate_res_from_ribs({:?})", res);
2293 let ribs = &all_ribs[rib_index + 1..];
2295 // An invalid forward use of a type parameter from a previous default.
2296 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2298 let res_error = if rib_ident.name == kw::SelfUpper {
2299 ResolutionError::SelfInTyParamDefault
2301 ResolutionError::ForwardDeclaredTyParam
2303 self.report_error(span, res_error);
2305 assert_eq!(res, Res::Err);
2311 use ResolutionError::*;
2312 let mut res_err = None;
2318 | MacroDefinition(..)
2319 | ForwardTyParamBanRibKind => {
2320 // Nothing to do. Continue.
2322 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2323 // This was an attempt to access an upvar inside a
2324 // named function item. This is not allowed, so we
2327 // We don't immediately trigger a resolve error, because
2328 // we want certain other resolution errors (namely those
2329 // emitted for `ConstantItemRibKind` below) to take
2331 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2334 ConstantItemRibKind => {
2335 // Still doesn't deal with upvars
2337 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2343 if let Some(res_err) = res_err {
2344 self.report_error(span, res_err);
2348 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2350 let has_generic_params = match rib.kind {
2354 | MacroDefinition(..)
2355 | ForwardTyParamBanRibKind
2356 | ConstantItemRibKind => {
2357 // Nothing to do. Continue.
2360 // This was an attempt to use a type parameter outside its scope.
2361 ItemRibKind(has_generic_params) => has_generic_params,
2362 FnItemRibKind => HasGenericParams::Yes,
2368 ResolutionError::GenericParamsFromOuterFunction(
2377 Res::Def(DefKind::ConstParam, _) => {
2378 let mut ribs = ribs.iter().peekable();
2379 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2380 // When declaring const parameters inside function signatures, the first rib
2381 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2382 // (spuriously) conflicting with the const param.
2386 let has_generic_params = match rib.kind {
2387 ItemRibKind(has_generic_params) => has_generic_params,
2388 FnItemRibKind => HasGenericParams::Yes,
2392 // This was an attempt to use a const parameter outside its scope.
2396 ResolutionError::GenericParamsFromOuterFunction(
2410 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2411 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2412 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2413 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2417 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2418 vis.is_accessible_from(module.normal_ancestor_id, self)
2421 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2422 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2423 if !ptr::eq(module, old_module) {
2424 span_bug!(binding.span, "parent module is reset for binding");
2429 fn disambiguate_legacy_vs_modern(
2431 legacy: &'a NameBinding<'a>,
2432 modern: &'a NameBinding<'a>,
2434 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
2435 // is disambiguated to mitigate regressions from macro modularization.
2436 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2438 self.binding_parent_modules.get(&PtrKey(legacy)),
2439 self.binding_parent_modules.get(&PtrKey(modern)),
2441 (Some(legacy), Some(modern)) => {
2442 legacy.normal_ancestor_id == modern.normal_ancestor_id
2443 && modern.is_ancestor_of(legacy)
2449 fn report_errors(&mut self, krate: &Crate) {
2450 self.report_with_use_injections(krate);
2452 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2453 let msg = "macro-expanded `macro_export` macros from the current crate \
2454 cannot be referred to by absolute paths";
2455 self.lint_buffer.buffer_lint_with_diagnostic(
2456 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2460 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2464 for ambiguity_error in &self.ambiguity_errors {
2465 self.report_ambiguity_error(ambiguity_error);
2468 let mut reported_spans = FxHashSet::default();
2469 for error in &self.privacy_errors {
2470 if reported_spans.insert(error.dedup_span) {
2471 self.report_privacy_error(error);
2476 fn report_with_use_injections(&mut self, krate: &Crate) {
2477 for UseError { mut err, candidates, node_id, better, suggestion } in
2478 self.use_injections.drain(..)
2480 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
2481 if !candidates.is_empty() {
2482 diagnostics::show_candidates(&mut err, span, &candidates, better, found_use);
2484 if let Some((span, msg, sugg, appl)) = suggestion {
2485 err.span_suggestion(span, msg, sugg, appl);
2491 fn report_conflict<'b>(
2496 new_binding: &NameBinding<'b>,
2497 old_binding: &NameBinding<'b>,
2499 // Error on the second of two conflicting names
2500 if old_binding.span.lo() > new_binding.span.lo() {
2501 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2504 let container = match parent.kind {
2505 ModuleKind::Def(DefKind::Mod, _, _) => "module",
2506 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
2507 ModuleKind::Block(..) => "block",
2511 let old_noun = match old_binding.is_import() {
2513 false => "definition",
2516 let new_participle = match new_binding.is_import() {
2521 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
2523 if let Some(s) = self.name_already_seen.get(&name) {
2529 let old_kind = match (ns, old_binding.module()) {
2530 (ValueNS, _) => "value",
2531 (MacroNS, _) => "macro",
2532 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2533 (TypeNS, Some(module)) if module.is_normal() => "module",
2534 (TypeNS, Some(module)) if module.is_trait() => "trait",
2535 (TypeNS, _) => "type",
2538 let msg = format!("the name `{}` is defined multiple times", name);
2540 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2541 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2542 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2543 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2544 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2546 _ => match (old_binding.is_import(), new_binding.is_import()) {
2547 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2548 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2549 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2554 "`{}` must be defined only once in the {} namespace of this {}",
2560 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2562 self.session.source_map().def_span(old_binding.span),
2563 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2566 // See https://github.com/rust-lang/rust/issues/32354
2567 use NameBindingKind::Import;
2568 let directive = match (&new_binding.kind, &old_binding.kind) {
2569 // If there are two imports where one or both have attributes then prefer removing the
2570 // import without attributes.
2571 (Import { directive: new, .. }, Import { directive: old, .. })
2573 !new_binding.span.is_dummy()
2574 && !old_binding.span.is_dummy()
2575 && (new.has_attributes || old.has_attributes)
2578 if old.has_attributes {
2579 Some((new, new_binding.span, true))
2581 Some((old, old_binding.span, true))
2584 // Otherwise prioritize the new binding.
2585 (Import { directive, .. }, other) if !new_binding.span.is_dummy() => {
2586 Some((directive, new_binding.span, other.is_import()))
2588 (other, Import { directive, .. }) if !old_binding.span.is_dummy() => {
2589 Some((directive, old_binding.span, other.is_import()))
2594 // Check if the target of the use for both bindings is the same.
2595 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2596 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2598 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2599 // Only suggest removing an import if both bindings are to the same def, if both spans
2600 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2601 // been introduced by a item.
2602 let should_remove_import = duplicate
2604 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2607 Some((directive, span, true)) if should_remove_import && directive.is_nested() => {
2608 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span)
2610 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
2611 // Simple case - remove the entire import. Due to the above match arm, this can
2612 // only be a single use so just remove it entirely.
2613 err.tool_only_span_suggestion(
2614 directive.use_span_with_attributes,
2615 "remove unnecessary import",
2617 Applicability::MaybeIncorrect,
2620 Some((directive, span, _)) => {
2621 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span)
2627 self.name_already_seen.insert(name, span);
2630 /// This function adds a suggestion to change the binding name of a new import that conflicts
2631 /// with an existing import.
2633 /// ```ignore (diagnostic)
2634 /// help: you can use `as` to change the binding name of the import
2636 /// LL | use foo::bar as other_bar;
2637 /// | ^^^^^^^^^^^^^^^^^^^^^
2639 fn add_suggestion_for_rename_of_use(
2641 err: &mut DiagnosticBuilder<'_>,
2643 directive: &ImportDirective<'_>,
2646 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2647 format!("Other{}", name)
2649 format!("other_{}", name)
2652 let mut suggestion = None;
2653 match directive.subclass {
2654 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } => {
2655 suggestion = Some(format!("self as {}", suggested_name))
2657 ImportDirectiveSubclass::SingleImport { source, .. } => {
2659 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2661 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2662 if pos <= snippet.len() {
2663 suggestion = Some(format!(
2667 if snippet.ends_with(";") { ";" } else { "" }
2673 ImportDirectiveSubclass::ExternCrate { source, target, .. } => {
2674 suggestion = Some(format!(
2675 "extern crate {} as {};",
2676 source.unwrap_or(target.name),
2680 _ => unreachable!(),
2683 let rename_msg = "you can use `as` to change the binding name of the import";
2684 if let Some(suggestion) = suggestion {
2685 err.span_suggestion(
2689 Applicability::MaybeIncorrect,
2692 err.span_label(binding_span, rename_msg);
2696 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2697 /// nested. In the following example, this function will be invoked to remove the `a` binding
2698 /// in the second use statement:
2700 /// ```ignore (diagnostic)
2701 /// use issue_52891::a;
2702 /// use issue_52891::{d, a, e};
2705 /// The following suggestion will be added:
2707 /// ```ignore (diagnostic)
2708 /// use issue_52891::{d, a, e};
2709 /// ^-- help: remove unnecessary import
2712 /// If the nested use contains only one import then the suggestion will remove the entire
2715 /// It is expected that the directive provided is a nested import - this isn't checked by the
2716 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2717 /// as characters expected by span manipulations won't be present.
2718 fn add_suggestion_for_duplicate_nested_use(
2720 err: &mut DiagnosticBuilder<'_>,
2721 directive: &ImportDirective<'_>,
2724 assert!(directive.is_nested());
2725 let message = "remove unnecessary import";
2727 // Two examples will be used to illustrate the span manipulations we're doing:
2729 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
2730 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
2731 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
2732 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
2734 let (found_closing_brace, span) =
2735 find_span_of_binding_until_next_binding(self.session, binding_span, directive.use_span);
2737 // If there was a closing brace then identify the span to remove any trailing commas from
2738 // previous imports.
2739 if found_closing_brace {
2740 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
2741 err.tool_only_span_suggestion(
2745 Applicability::MaybeIncorrect,
2748 // Remove the entire line if we cannot extend the span back, this indicates a
2749 // `issue_52891::{self}` case.
2750 err.span_suggestion(
2751 directive.use_span_with_attributes,
2754 Applicability::MaybeIncorrect,
2761 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
2764 fn extern_prelude_get(
2768 ) -> Option<&'a NameBinding<'a>> {
2769 if ident.is_path_segment_keyword() {
2770 // Make sure `self`, `super` etc produce an error when passed to here.
2773 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
2774 if let Some(binding) = entry.extern_crate_item {
2775 if !speculative && entry.introduced_by_item {
2776 self.record_use(ident, TypeNS, binding, false);
2780 let crate_id = if !speculative {
2781 self.crate_loader.process_path_extern(ident.name, ident.span)
2782 } else if let Some(crate_id) =
2783 self.crate_loader.maybe_process_path_extern(ident.name, ident.span)
2789 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2791 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
2792 .to_name_binding(self.arenas),
2798 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
2799 /// isn't something that can be returned because it can't be made to live that long,
2800 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
2801 /// just that an error occurred.
2802 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
2803 pub fn resolve_str_path_error(
2809 ) -> Result<(ast::Path, Res), ()> {
2810 let path = if path_str.starts_with("::") {
2813 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
2814 .chain({ path_str.split("::").skip(1).map(Ident::from_str) })
2815 .map(|i| self.new_ast_path_segment(i))
2823 .map(Ident::from_str)
2824 .map(|i| self.new_ast_path_segment(i))
2828 let module = self.block_map.get(&module_id).copied().unwrap_or_else(|| {
2829 let def_id = self.definitions.local_def_id(module_id);
2830 self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
2832 let parent_scope = &ParentScope::module(module);
2833 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
2837 // Resolve a path passed from rustdoc or HIR lowering.
2838 fn resolve_ast_path(
2842 parent_scope: &ParentScope<'a>,
2843 ) -> Result<Res, (Span, ResolutionError<'a>)> {
2844 match self.resolve_path(
2845 &Segment::from_path(path),
2852 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
2853 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
2854 Ok(path_res.base_res())
2856 PathResult::NonModule(..) => Err((
2858 ResolutionError::FailedToResolve {
2859 label: String::from("type-relative paths are not supported in this context"),
2863 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
2864 PathResult::Failed { span, label, suggestion, .. } => {
2865 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
2870 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
2871 let mut seg = ast::PathSegment::from_ident(ident);
2872 seg.id = self.next_node_id();
2877 pub fn graph_root(&self) -> Module<'a> {
2882 pub fn all_macros(&self) -> &FxHashMap<Name, Res> {
2887 fn names_to_string(names: &[Name]) -> String {
2888 let mut result = String::new();
2889 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
2891 result.push_str("::");
2893 if Ident::with_dummy_span(*name).is_raw_guess() {
2894 result.push_str("r#");
2896 result.push_str(&name.as_str());
2901 fn path_names_to_string(path: &Path) -> String {
2902 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
2905 /// A somewhat inefficient routine to obtain the name of a module.
2906 fn module_to_string(module: Module<'_>) -> Option<String> {
2907 let mut names = Vec::new();
2909 fn collect_mod(names: &mut Vec<Name>, module: Module<'_>) {
2910 if let ModuleKind::Def(.., name) = module.kind {
2911 if let Some(parent) = module.parent {
2913 collect_mod(names, parent);
2916 names.push(Name::intern("<opaque>"));
2917 collect_mod(names, module.parent.unwrap());
2920 collect_mod(&mut names, module);
2922 if names.is_empty() {
2926 Some(names_to_string(&names))
2929 #[derive(Copy, Clone, Debug)]
2931 /// Do not issue the lint.
2934 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
2935 /// In this case, we can take the span of that path.
2938 /// This lint comes from a `use` statement. In this case, what we
2939 /// care about really is the *root* `use` statement; e.g., if we
2940 /// have nested things like `use a::{b, c}`, we care about the
2942 UsePath { root_id: NodeId, root_span: Span },
2944 /// This is the "trait item" from a fully qualified path. For example,
2945 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
2946 /// The `path_span` is the span of the to the trait itself (`X::Y`).
2947 QPathTrait { qpath_id: NodeId, qpath_span: Span },
2951 fn node_id(&self) -> Option<NodeId> {
2953 CrateLint::No => None,
2954 CrateLint::SimplePath(id)
2955 | CrateLint::UsePath { root_id: id, .. }
2956 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
2961 pub fn provide(providers: &mut Providers<'_>) {
2962 lifetimes::provide(providers);