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 #![feature(or_patterns)]
14 #![recursion_limit = "256"]
16 pub use rustc_hir::def::{Namespace, PerNS};
20 use rustc_ast::ast::{self, FloatTy, Ident, IntTy, Name, NodeId, UintTy};
21 use rustc_ast::ast::{Crate, CRATE_NODE_ID};
22 use rustc_ast::ast::{ItemKind, Path};
24 use rustc_ast::node_id::{NodeMap, NodeSet};
25 use rustc_ast::unwrap_or;
26 use rustc_ast::visit::{self, Visitor};
27 use rustc_ast_pretty::pprust;
28 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
29 use rustc_data_structures::ptr_key::PtrKey;
30 use rustc_data_structures::sync::Lrc;
31 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
32 use rustc_expand::base::SyntaxExtension;
33 use rustc_hir::def::Namespace::*;
34 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
35 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
36 use rustc_hir::definitions::{DefKey, Definitions};
37 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
38 use rustc_hir::{GlobMap, TraitMap};
39 use rustc_metadata::creader::{CStore, CrateLoader};
40 use rustc_middle::hir::exports::ExportMap;
41 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
42 use rustc_middle::span_bug;
43 use rustc_middle::ty::query::Providers;
44 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
45 use rustc_session::lint;
46 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
47 use rustc_session::Session;
48 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
49 use rustc_span::source_map::Spanned;
50 use rustc_span::symbol::{kw, sym};
51 use rustc_span::{Span, DUMMY_SP};
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::{Import, ImportKind, ImportResolver, NameResolution};
61 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
62 use macros::{MacroRulesBinding, MacroRulesScope};
64 type Res = def::Res<NodeId>;
66 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(MacroRulesScope<'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 macro_rules: MacroRulesScope<'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> {
141 expansion: ExpnId::root(),
142 macro_rules: MacroRulesScope::Empty,
149 struct BindingError {
151 origin: BTreeSet<Span>,
152 target: BTreeSet<Span>,
156 impl PartialOrd for BindingError {
157 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
158 Some(self.cmp(other))
162 impl PartialEq for BindingError {
163 fn eq(&self, other: &BindingError) -> bool {
164 self.name == other.name
168 impl Ord for BindingError {
169 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
170 self.name.cmp(&other.name)
174 enum ResolutionError<'a> {
175 /// Error E0401: can't use type or const parameters from outer function.
176 GenericParamsFromOuterFunction(Res, HasGenericParams),
177 /// Error E0403: the name is already used for a type or const parameter in this generic
179 NameAlreadyUsedInParameterList(Name, Span),
180 /// Error E0407: method is not a member of trait.
181 MethodNotMemberOfTrait(Name, &'a str),
182 /// Error E0437: type is not a member of trait.
183 TypeNotMemberOfTrait(Name, &'a str),
184 /// Error E0438: const is not a member of trait.
185 ConstNotMemberOfTrait(Name, &'a str),
186 /// Error E0408: variable `{}` is not bound in all patterns.
187 VariableNotBoundInPattern(&'a BindingError),
188 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
189 VariableBoundWithDifferentMode(Name, Span),
190 /// Error E0415: identifier is bound more than once in this parameter list.
191 IdentifierBoundMoreThanOnceInParameterList(&'a str),
192 /// Error E0416: identifier is bound more than once in the same pattern.
193 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
194 /// Error E0426: use of undeclared label.
195 UndeclaredLabel(&'a str, Option<Name>),
196 /// Error E0429: `self` imports are only allowed within a `{ }` list.
197 SelfImportsOnlyAllowedWithin,
198 /// Error E0430: `self` import can only appear once in the list.
199 SelfImportCanOnlyAppearOnceInTheList,
200 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
201 SelfImportOnlyInImportListWithNonEmptyPrefix,
202 /// Error E0433: failed to resolve.
203 FailedToResolve { label: String, suggestion: Option<Suggestion> },
204 /// Error E0434: can't capture dynamic environment in a fn item.
205 CannotCaptureDynamicEnvironmentInFnItem,
206 /// Error E0435: attempt to use a non-constant value in a constant.
207 AttemptToUseNonConstantValueInConstant,
208 /// Error E0530: `X` bindings cannot shadow `Y`s.
209 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
210 /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
211 ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
212 /// Error E0735: type parameters with a default cannot use `Self`
213 SelfInTyParamDefault,
216 enum VisResolutionError<'a> {
217 Relative2018(Span, &'a ast::Path),
219 FailedToResolve(Span, String, Option<Suggestion>),
220 ExpectedFound(Span, String, Res),
225 // A minimal representation of a path segment. We use this in resolve because
226 // we synthesize 'path segments' which don't have the rest of an AST or HIR
228 #[derive(Clone, Copy, Debug)]
235 fn from_path(path: &Path) -> Vec<Segment> {
236 path.segments.iter().map(|s| s.into()).collect()
239 fn from_ident(ident: Ident) -> Segment {
240 Segment { ident, id: None }
243 fn names_to_string(segments: &[Segment]) -> String {
244 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
248 impl<'a> From<&'a ast::PathSegment> for Segment {
249 fn from(seg: &'a ast::PathSegment) -> Segment {
250 Segment { ident: seg.ident, id: Some(seg.id) }
254 struct UsePlacementFinder {
255 target_module: NodeId,
260 impl UsePlacementFinder {
261 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
262 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
263 visit::walk_crate(&mut finder, krate);
264 (finder.span, finder.found_use)
268 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
271 module: &'tcx ast::Mod,
273 _: &[ast::Attribute],
276 if self.span.is_some() {
279 if node_id != self.target_module {
280 visit::walk_mod(self, module);
283 // find a use statement
284 for item in &module.items {
286 ItemKind::Use(..) => {
287 // don't suggest placing a use before the prelude
288 // import or other generated ones
289 if !item.span.from_expansion() {
290 self.span = Some(item.span.shrink_to_lo());
291 self.found_use = true;
295 // don't place use before extern crate
296 ItemKind::ExternCrate(_) => {}
297 // but place them before the first other item
299 if self.span.map_or(true, |span| item.span < span) {
300 if !item.span.from_expansion() {
301 // don't insert between attributes and an item
302 if item.attrs.is_empty() {
303 self.span = Some(item.span.shrink_to_lo());
305 // find the first attribute on the item
306 for attr in &item.attrs {
307 if self.span.map_or(true, |span| attr.span < span) {
308 self.span = Some(attr.span.shrink_to_lo());
320 /// An intermediate resolution result.
322 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
323 /// items are visible in their whole block, while `Res`es only from the place they are defined
326 enum LexicalScopeBinding<'a> {
327 Item(&'a NameBinding<'a>),
331 impl<'a> LexicalScopeBinding<'a> {
332 fn res(self) -> Res {
334 LexicalScopeBinding::Item(binding) => binding.res(),
335 LexicalScopeBinding::Res(res) => res,
340 #[derive(Copy, Clone, Debug)]
341 enum ModuleOrUniformRoot<'a> {
345 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
346 CrateRootAndExternPrelude,
348 /// Virtual module that denotes resolution in extern prelude.
349 /// Used for paths starting with `::` on 2018 edition.
352 /// Virtual module that denotes resolution in current scope.
353 /// Used only for resolving single-segment imports. The reason it exists is that import paths
354 /// are always split into two parts, the first of which should be some kind of module.
358 impl ModuleOrUniformRoot<'_> {
359 fn same_def(lhs: Self, rhs: Self) -> bool {
361 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
362 lhs.def_id() == rhs.def_id()
365 ModuleOrUniformRoot::CrateRootAndExternPrelude,
366 ModuleOrUniformRoot::CrateRootAndExternPrelude,
368 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
369 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
375 #[derive(Clone, Debug)]
376 enum PathResult<'a> {
377 Module(ModuleOrUniformRoot<'a>),
378 NonModule(PartialRes),
383 suggestion: Option<Suggestion>,
384 is_error_from_last_segment: bool,
389 /// An anonymous module; e.g., just a block.
394 /// { // This is an anonymous module
395 /// f(); // This resolves to (2) as we are inside the block.
398 /// f(); // Resolves to (1)
402 /// Any module with a name.
406 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
407 /// * A trait or an enum (it implicitly contains associated types, methods and variant
409 Def(DefKind, DefId, Name),
413 /// Get name of the module.
414 pub fn name(&self) -> Option<Name> {
416 ModuleKind::Block(..) => None,
417 ModuleKind::Def(.., name) => Some(*name),
422 /// A key that identifies a binding in a given `Module`.
424 /// Multiple bindings in the same module can have the same key (in a valid
425 /// program) if all but one of them come from glob imports.
426 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
428 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
432 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
433 /// `_` in the expanded AST that introduced this binding.
437 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
439 /// One node in the tree of modules.
440 pub struct ModuleData<'a> {
441 parent: Option<Module<'a>>,
444 // The def id of the closest normal module (`mod`) ancestor (including this module).
445 normal_ancestor_id: DefId,
447 // Mapping between names and their (possibly in-progress) resolutions in this module.
448 // Resolutions in modules from other crates are not populated until accessed.
449 lazy_resolutions: Resolutions<'a>,
450 // True if this is a module from other crate that needs to be populated on access.
451 populate_on_access: Cell<bool>,
453 // Macro invocations that can expand into items in this module.
454 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
456 no_implicit_prelude: bool,
458 glob_importers: RefCell<Vec<&'a Import<'a>>>,
459 globs: RefCell<Vec<&'a Import<'a>>>,
461 // Used to memoize the traits in this module for faster searches through all traits in scope.
462 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
464 /// Span of the module itself. Used for error reporting.
470 type Module<'a> = &'a ModuleData<'a>;
472 impl<'a> ModuleData<'a> {
474 parent: Option<Module<'a>>,
476 normal_ancestor_id: DefId,
484 lazy_resolutions: Default::default(),
485 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
486 unexpanded_invocations: Default::default(),
487 no_implicit_prelude: false,
488 glob_importers: RefCell::new(Vec::new()),
489 globs: RefCell::new(Vec::new()),
490 traits: RefCell::new(None),
496 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
498 R: AsMut<Resolver<'a>>,
499 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
501 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
502 if let Some(binding) = name_resolution.borrow().binding {
503 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 | 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>, import: &'a Import<'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)]
624 MacroRulesVsModularized,
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::MacroRulesVsModularized => {
638 "`macro_rules` vs non-`macro_rules` from other module"
640 AmbiguityKind::GlobVsOuter => {
641 "glob import vs any other name from outer scope during import/macro resolution"
643 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
644 AmbiguityKind::GlobVsExpanded => {
645 "glob import vs macro-expanded name in the same \
646 module during import/macro resolution"
648 AmbiguityKind::MoreExpandedVsOuter => {
649 "macro-expanded name vs less macro-expanded name \
650 from outer scope during import/macro resolution"
656 /// Miscellaneous bits of metadata for better ambiguity error reporting.
657 #[derive(Clone, Copy, PartialEq)]
658 enum AmbiguityErrorMisc {
665 struct AmbiguityError<'a> {
668 b1: &'a NameBinding<'a>,
669 b2: &'a NameBinding<'a>,
670 misc1: AmbiguityErrorMisc,
671 misc2: AmbiguityErrorMisc,
674 impl<'a> NameBinding<'a> {
675 fn module(&self) -> Option<Module<'a>> {
677 NameBindingKind::Module(module) => Some(module),
678 NameBindingKind::Import { binding, .. } => binding.module(),
683 fn res(&self) -> Res {
685 NameBindingKind::Res(res, _) => res,
686 NameBindingKind::Module(module) => module.res().unwrap(),
687 NameBindingKind::Import { binding, .. } => binding.res(),
691 fn is_ambiguity(&self) -> bool {
692 self.ambiguity.is_some()
694 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
699 // We sometimes need to treat variants as `pub` for backwards compatibility.
700 fn pseudo_vis(&self) -> ty::Visibility {
701 if self.is_variant() && self.res().def_id().is_local() {
702 ty::Visibility::Public
708 fn is_variant(&self) -> bool {
710 NameBindingKind::Res(
711 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
718 fn is_extern_crate(&self) -> bool {
720 NameBindingKind::Import {
721 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
724 NameBindingKind::Module(&ModuleData {
725 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
727 }) => def_id.index == CRATE_DEF_INDEX,
732 fn is_import(&self) -> bool {
734 NameBindingKind::Import { .. } => true,
739 fn is_glob_import(&self) -> bool {
741 NameBindingKind::Import { import, .. } => import.is_glob(),
746 fn is_importable(&self) -> bool {
748 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _) => false,
753 fn is_macro_def(&self) -> bool {
755 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
760 fn macro_kind(&self) -> Option<MacroKind> {
761 self.res().macro_kind()
764 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
765 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
766 // Then this function returns `true` if `self` may emerge from a macro *after* that
767 // in some later round and screw up our previously found resolution.
768 // See more detailed explanation in
769 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
770 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
771 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
772 // Expansions are partially ordered, so "may appear after" is an inversion of
773 // "certainly appears before or simultaneously" and includes unordered cases.
774 let self_parent_expansion = self.expansion;
775 let other_parent_expansion = binding.expansion;
776 let certainly_before_other_or_simultaneously =
777 other_parent_expansion.is_descendant_of(self_parent_expansion);
778 let certainly_before_invoc_or_simultaneously =
779 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
780 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
784 /// Interns the names of the primitive types.
786 /// All other types are defined somewhere and possibly imported, but the primitive ones need
787 /// special handling, since they have no place of origin.
788 struct PrimitiveTypeTable {
789 primitive_types: FxHashMap<Name, PrimTy>,
792 impl PrimitiveTypeTable {
793 fn new() -> PrimitiveTypeTable {
794 let mut table = FxHashMap::default();
796 table.insert(sym::bool, Bool);
797 table.insert(sym::char, Char);
798 table.insert(sym::f32, Float(FloatTy::F32));
799 table.insert(sym::f64, Float(FloatTy::F64));
800 table.insert(sym::isize, Int(IntTy::Isize));
801 table.insert(sym::i8, Int(IntTy::I8));
802 table.insert(sym::i16, Int(IntTy::I16));
803 table.insert(sym::i32, Int(IntTy::I32));
804 table.insert(sym::i64, Int(IntTy::I64));
805 table.insert(sym::i128, Int(IntTy::I128));
806 table.insert(sym::str, Str);
807 table.insert(sym::usize, Uint(UintTy::Usize));
808 table.insert(sym::u8, Uint(UintTy::U8));
809 table.insert(sym::u16, Uint(UintTy::U16));
810 table.insert(sym::u32, Uint(UintTy::U32));
811 table.insert(sym::u64, Uint(UintTy::U64));
812 table.insert(sym::u128, Uint(UintTy::U128));
813 Self { primitive_types: table }
817 #[derive(Debug, Default, Clone)]
818 pub struct ExternPreludeEntry<'a> {
819 extern_crate_item: Option<&'a NameBinding<'a>>,
820 pub introduced_by_item: bool,
823 /// The main resolver class.
825 /// This is the visitor that walks the whole crate.
826 pub struct Resolver<'a> {
827 session: &'a Session,
829 definitions: Definitions,
831 graph_root: Module<'a>,
833 prelude: Option<Module<'a>>,
834 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
836 /// N.B., this is used only for better diagnostics, not name resolution itself.
837 has_self: FxHashSet<DefId>,
839 /// Names of fields of an item `DefId` accessible with dot syntax.
840 /// Used for hints during error reporting.
841 field_names: FxHashMap<DefId, Vec<Spanned<Name>>>,
843 /// All imports known to succeed or fail.
844 determined_imports: Vec<&'a Import<'a>>,
846 /// All non-determined imports.
847 indeterminate_imports: Vec<&'a Import<'a>>,
849 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
850 /// We are resolving a last import segment during import validation.
851 last_import_segment: bool,
852 /// This binding should be ignored during in-module resolution, so that we don't get
853 /// "self-confirming" import resolutions during import validation.
854 blacklisted_binding: Option<&'a NameBinding<'a>>,
856 /// The idents for the primitive types.
857 primitive_type_table: PrimitiveTypeTable,
859 /// Resolutions for nodes that have a single resolution.
860 partial_res_map: NodeMap<PartialRes>,
861 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
862 import_res_map: NodeMap<PerNS<Option<Res>>>,
863 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
864 label_res_map: NodeMap<NodeId>,
866 /// `CrateNum` resolutions of `extern crate` items.
867 extern_crate_map: NodeMap<CrateNum>,
868 export_map: ExportMap<NodeId>,
869 trait_map: TraitMap<NodeId>,
871 /// A map from nodes to anonymous modules.
872 /// Anonymous modules are pseudo-modules that are implicitly created around items
873 /// contained within blocks.
875 /// For example, if we have this:
883 /// There will be an anonymous module created around `g` with the ID of the
884 /// entry block for `f`.
885 block_map: NodeMap<Module<'a>>,
886 /// A fake module that contains no definition and no prelude. Used so that
887 /// some AST passes can generate identifiers that only resolve to local or
889 empty_module: Module<'a>,
890 module_map: FxHashMap<LocalDefId, Module<'a>>,
891 extern_module_map: FxHashMap<DefId, Module<'a>>,
892 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
893 underscore_disambiguator: u32,
895 /// Maps glob imports to the names of items actually imported.
898 used_imports: FxHashSet<(NodeId, Namespace)>,
899 maybe_unused_trait_imports: NodeSet,
900 maybe_unused_extern_crates: Vec<(NodeId, Span)>,
902 /// Privacy errors are delayed until the end in order to deduplicate them.
903 privacy_errors: Vec<PrivacyError<'a>>,
904 /// Ambiguity errors are delayed for deduplication.
905 ambiguity_errors: Vec<AmbiguityError<'a>>,
906 /// `use` injections are delayed for better placement and deduplication.
907 use_injections: Vec<UseError<'a>>,
908 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
909 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
911 arenas: &'a ResolverArenas<'a>,
912 dummy_binding: &'a NameBinding<'a>,
914 crate_loader: CrateLoader<'a>,
915 macro_names: FxHashSet<Ident>,
916 builtin_macros: FxHashMap<Name, SyntaxExtension>,
917 registered_attrs: FxHashSet<Ident>,
918 registered_tools: FxHashSet<Ident>,
919 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
920 all_macros: FxHashMap<Name, Res>,
921 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
922 dummy_ext_bang: Lrc<SyntaxExtension>,
923 dummy_ext_derive: Lrc<SyntaxExtension>,
924 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
925 macro_defs: FxHashMap<ExpnId, DefId>,
926 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
927 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
928 unused_macros: NodeMap<Span>,
929 proc_macro_stubs: NodeSet,
930 /// Traces collected during macro resolution and validated when it's complete.
931 single_segment_macro_resolutions:
932 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
933 multi_segment_macro_resolutions:
934 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
935 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
936 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
937 /// Derive macros cannot modify the item themselves and have to store the markers in the global
938 /// context, so they attach the markers to derive container IDs using this resolver table.
939 containers_deriving_copy: FxHashSet<ExpnId>,
940 /// Parent scopes in which the macros were invoked.
941 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
942 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
943 /// `macro_rules` scopes *produced* by expanding the macro invocations,
944 /// include all the `macro_rules` items and other invocations generated by them.
945 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScope<'a>>,
946 /// Helper attributes that are in scope for the given expansion.
947 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
949 /// Avoid duplicated errors for "name already defined".
950 name_already_seen: FxHashMap<Name, Span>,
952 potentially_unused_imports: Vec<&'a Import<'a>>,
954 /// Table for mapping struct IDs into struct constructor IDs,
955 /// it's not used during normal resolution, only for better error reporting.
956 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
958 /// Features enabled for this crate.
959 active_features: FxHashSet<Name>,
961 /// Stores enum visibilities to properly build a reduced graph
962 /// when visiting the correspondent variants.
963 variant_vis: DefIdMap<ty::Visibility>,
965 lint_buffer: LintBuffer,
967 next_node_id: NodeId,
970 /// Nothing really interesting here; it just provides memory for the rest of the crate.
972 pub struct ResolverArenas<'a> {
973 modules: arena::TypedArena<ModuleData<'a>>,
974 local_modules: RefCell<Vec<Module<'a>>>,
975 name_bindings: arena::TypedArena<NameBinding<'a>>,
976 imports: arena::TypedArena<Import<'a>>,
977 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
978 macro_rules_bindings: arena::TypedArena<MacroRulesBinding<'a>>,
979 ast_paths: arena::TypedArena<ast::Path>,
982 impl<'a> ResolverArenas<'a> {
983 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
984 let module = self.modules.alloc(module);
985 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
986 self.local_modules.borrow_mut().push(module);
990 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
991 self.local_modules.borrow()
993 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
994 self.name_bindings.alloc(name_binding)
996 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
997 self.imports.alloc(import)
999 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1000 self.name_resolutions.alloc(Default::default())
1002 fn alloc_macro_rules_binding(
1004 binding: MacroRulesBinding<'a>,
1005 ) -> &'a MacroRulesBinding<'a> {
1006 self.macro_rules_bindings.alloc(binding)
1008 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1009 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1013 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1014 fn as_mut(&mut self) -> &mut Resolver<'a> {
1019 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1020 fn parent(self, id: DefId) -> Option<DefId> {
1021 match id.as_local() {
1022 Some(id) => self.definitions.def_key(id).parent,
1023 None => self.cstore().def_key(id).parent,
1025 .map(|index| DefId { index, ..id })
1029 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1030 /// the resolver is no longer needed as all the relevant information is inline.
1031 impl rustc_ast_lowering::Resolver for Resolver<'_> {
1032 fn def_key(&mut self, id: DefId) -> DefKey {
1033 if let Some(id) = id.as_local() {
1034 self.definitions().def_key(id)
1036 self.cstore().def_key(id)
1040 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1041 self.cstore().item_generics_num_lifetimes(def_id, sess)
1044 fn resolve_str_path(
1047 crate_root: Option<Name>,
1048 components: &[Name],
1050 ) -> (ast::Path, Res) {
1051 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1052 let segments = iter::once(Ident::with_dummy_span(root))
1056 .chain(components.iter().cloned())
1057 .map(Ident::with_dummy_span),
1059 .map(|i| self.new_ast_path_segment(i))
1060 .collect::<Vec<_>>();
1062 let path = ast::Path { span, segments };
1064 let parent_scope = &ParentScope::module(self.graph_root);
1065 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1067 Err((span, error)) => {
1068 self.report_error(span, error);
1075 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1076 self.partial_res_map.get(&id).cloned()
1079 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1080 self.import_res_map.get(&id).cloned().unwrap_or_default()
1083 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1084 self.label_res_map.get(&id).cloned()
1087 fn definitions(&mut self) -> &mut Definitions {
1088 &mut self.definitions
1091 fn lint_buffer(&mut self) -> &mut LintBuffer {
1092 &mut self.lint_buffer
1095 fn next_node_id(&mut self) -> NodeId {
1100 impl<'a> Resolver<'a> {
1102 session: &'a Session,
1105 metadata_loader: &'a MetadataLoaderDyn,
1106 arenas: &'a ResolverArenas<'a>,
1108 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1109 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1110 let graph_root = arenas.alloc_module(ModuleData {
1111 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1112 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1114 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1115 let empty_module = arenas.alloc_module(ModuleData {
1116 no_implicit_prelude: true,
1125 let mut module_map = FxHashMap::default();
1126 module_map.insert(LocalDefId { local_def_index: CRATE_DEF_INDEX }, graph_root);
1128 let mut definitions = Definitions::default();
1129 definitions.create_root_def(crate_name, session.local_crate_disambiguator());
1131 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1135 .filter(|(_, entry)| entry.add_prelude)
1136 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1139 if !attr::contains_name(&krate.attrs, sym::no_core) {
1140 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1141 if !attr::contains_name(&krate.attrs, sym::no_std) {
1142 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1143 if session.rust_2018() {
1144 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1149 let (registered_attrs, registered_tools) =
1150 macros::registered_attrs_and_tools(session, &krate.attrs);
1152 let mut invocation_parent_scopes = FxHashMap::default();
1153 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1155 let mut macro_defs = FxHashMap::default();
1156 macro_defs.insert(ExpnId::root(), root_def_id);
1158 let features = session.features_untracked();
1159 let non_macro_attr =
1160 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1167 // The outermost module has def ID 0; this is not reflected in the
1173 has_self: FxHashSet::default(),
1174 field_names: FxHashMap::default(),
1176 determined_imports: Vec::new(),
1177 indeterminate_imports: Vec::new(),
1179 last_import_segment: false,
1180 blacklisted_binding: None,
1182 primitive_type_table: PrimitiveTypeTable::new(),
1184 partial_res_map: Default::default(),
1185 import_res_map: Default::default(),
1186 label_res_map: Default::default(),
1187 extern_crate_map: Default::default(),
1188 export_map: FxHashMap::default(),
1189 trait_map: Default::default(),
1190 underscore_disambiguator: 0,
1193 block_map: Default::default(),
1194 extern_module_map: FxHashMap::default(),
1195 binding_parent_modules: FxHashMap::default(),
1196 ast_transform_scopes: FxHashMap::default(),
1198 glob_map: Default::default(),
1200 used_imports: FxHashSet::default(),
1201 maybe_unused_trait_imports: Default::default(),
1202 maybe_unused_extern_crates: Vec::new(),
1204 privacy_errors: Vec::new(),
1205 ambiguity_errors: Vec::new(),
1206 use_injections: Vec::new(),
1207 macro_expanded_macro_export_errors: BTreeSet::new(),
1210 dummy_binding: arenas.alloc_name_binding(NameBinding {
1211 kind: NameBindingKind::Res(Res::Err, false),
1213 expansion: ExpnId::root(),
1215 vis: ty::Visibility::Public,
1218 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1219 macro_names: FxHashSet::default(),
1220 builtin_macros: Default::default(),
1223 macro_use_prelude: FxHashMap::default(),
1224 all_macros: FxHashMap::default(),
1225 macro_map: FxHashMap::default(),
1226 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1227 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1228 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1229 invocation_parent_scopes,
1230 output_macro_rules_scopes: Default::default(),
1231 helper_attrs: Default::default(),
1233 local_macro_def_scopes: FxHashMap::default(),
1234 name_already_seen: FxHashMap::default(),
1235 potentially_unused_imports: Vec::new(),
1236 struct_constructors: Default::default(),
1237 unused_macros: Default::default(),
1238 proc_macro_stubs: Default::default(),
1239 single_segment_macro_resolutions: Default::default(),
1240 multi_segment_macro_resolutions: Default::default(),
1241 builtin_attrs: Default::default(),
1242 containers_deriving_copy: Default::default(),
1243 active_features: features
1244 .declared_lib_features
1246 .map(|(feat, ..)| *feat)
1247 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1249 variant_vis: Default::default(),
1250 lint_buffer: LintBuffer::default(),
1251 next_node_id: NodeId::from_u32(1),
1255 pub fn next_node_id(&mut self) -> NodeId {
1260 .expect("input too large; ran out of NodeIds");
1261 self.next_node_id = ast::NodeId::from_usize(next);
1265 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1266 &mut self.lint_buffer
1269 pub fn arenas() -> ResolverArenas<'a> {
1273 pub fn into_outputs(self) -> ResolverOutputs {
1275 definitions: self.definitions,
1276 cstore: Box::new(self.crate_loader.into_cstore()),
1277 extern_crate_map: self.extern_crate_map,
1278 export_map: self.export_map,
1279 trait_map: self.trait_map,
1280 glob_map: self.glob_map,
1281 maybe_unused_trait_imports: self.maybe_unused_trait_imports,
1282 maybe_unused_extern_crates: self.maybe_unused_extern_crates,
1283 extern_prelude: self
1286 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1291 pub fn clone_outputs(&self) -> ResolverOutputs {
1293 definitions: self.definitions.clone(),
1294 cstore: Box::new(self.cstore().clone()),
1295 extern_crate_map: self.extern_crate_map.clone(),
1296 export_map: self.export_map.clone(),
1297 trait_map: self.trait_map.clone(),
1298 glob_map: self.glob_map.clone(),
1299 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1300 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1301 extern_prelude: self
1304 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1309 pub fn cstore(&self) -> &CStore {
1310 self.crate_loader.cstore()
1313 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1314 self.non_macro_attrs[mark_used as usize].clone()
1317 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1319 MacroKind::Bang => self.dummy_ext_bang.clone(),
1320 MacroKind::Derive => self.dummy_ext_derive.clone(),
1321 MacroKind::Attr => self.non_macro_attr(true),
1325 /// Runs the function on each namespace.
1326 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1332 fn is_builtin_macro(&mut self, res: Res) -> bool {
1333 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1336 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1338 match self.macro_defs.get(&ctxt.outer_expn()) {
1339 Some(&def_id) => return def_id,
1340 None => ctxt.remove_mark(),
1345 /// Entry point to crate resolution.
1346 pub fn resolve_crate(&mut self, krate: &Crate) {
1347 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1349 ImportResolver { r: self }.finalize_imports();
1350 self.finalize_macro_resolutions();
1352 self.late_resolve_crate(krate);
1354 self.check_unused(krate);
1355 self.report_errors(krate);
1356 self.crate_loader.postprocess(krate);
1363 normal_ancestor_id: DefId,
1367 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1368 self.arenas.alloc_module(module)
1371 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1372 let ident = ident.normalize_to_macros_2_0();
1373 let disambiguator = if ident.name == kw::Underscore {
1374 self.underscore_disambiguator += 1;
1375 self.underscore_disambiguator
1379 BindingKey { ident, ns, disambiguator }
1382 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1383 if module.populate_on_access.get() {
1384 module.populate_on_access.set(false);
1385 self.build_reduced_graph_external(module);
1387 &module.lazy_resolutions
1394 ) -> &'a RefCell<NameResolution<'a>> {
1396 .resolutions(module)
1399 .or_insert_with(|| self.arenas.alloc_name_resolution())
1406 used_binding: &'a NameBinding<'a>,
1407 is_lexical_scope: bool,
1409 if let Some((b2, kind)) = used_binding.ambiguity {
1410 self.ambiguity_errors.push(AmbiguityError {
1415 misc1: AmbiguityErrorMisc::None,
1416 misc2: AmbiguityErrorMisc::None,
1419 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1420 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1421 // but not introduce it, as used if they are accessed from lexical scope.
1422 if is_lexical_scope {
1423 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1424 if let Some(crate_item) = entry.extern_crate_item {
1425 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1432 import.used.set(true);
1433 self.used_imports.insert((import.id, ns));
1434 self.add_to_glob_map(&import, ident);
1435 self.record_use(ident, ns, binding, false);
1440 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1441 if import.is_glob() {
1442 self.glob_map.entry(import.id).or_default().insert(ident.name);
1446 /// A generic scope visitor.
1447 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1448 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1451 scope_set: ScopeSet,
1452 parent_scope: &ParentScope<'a>,
1454 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1456 // General principles:
1457 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1458 // built into the language or standard library. This way we can add new names into the
1459 // language or standard library without breaking user code.
1460 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1461 // Places to search (in order of decreasing priority):
1463 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1464 // (open set, not controlled).
1465 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1466 // (open, not controlled).
1467 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1468 // 4. Tool modules (closed, controlled right now, but not in the future).
1469 // 5. Standard library prelude (de-facto closed, controlled).
1470 // 6. Language prelude (closed, controlled).
1472 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1473 // (open set, not controlled).
1474 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1475 // (open, not controlled).
1476 // 3. Standard library prelude (de-facto closed, controlled).
1478 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1479 // are currently reported as errors. They should be higher in priority than preludes
1480 // and probably even names in modules according to the "general principles" above. They
1481 // also should be subject to restricted shadowing because are effectively produced by
1482 // derives (you need to resolve the derive first to add helpers into scope), but they
1483 // should be available before the derive is expanded for compatibility.
1484 // It's mess in general, so we are being conservative for now.
1485 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1486 // priority than prelude macros, but create ambiguities with macros in modules.
1487 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1488 // (open, not controlled). Have higher priority than prelude macros, but create
1489 // ambiguities with `macro_rules`.
1490 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1491 // 4a. User-defined prelude from macro-use
1492 // (open, the open part is from macro expansions, not controlled).
1493 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1494 // 4c. Standard library prelude (de-facto closed, controlled).
1495 // 6. Language prelude: builtin attributes (closed, controlled).
1497 let rust_2015 = ident.span.rust_2015();
1498 let (ns, macro_kind, is_absolute_path) = match scope_set {
1499 ScopeSet::All(ns, _) => (ns, None, false),
1500 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1501 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1503 // Jump out of trait or enum modules, they do not act as scopes.
1504 let module = parent_scope.module.nearest_item_scope();
1505 let mut scope = match ns {
1506 _ if is_absolute_path => Scope::CrateRoot,
1507 TypeNS | ValueNS => Scope::Module(module),
1508 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1510 let mut ident = ident.normalize_to_macros_2_0();
1511 let mut use_prelude = !module.no_implicit_prelude;
1514 let visit = match scope {
1515 // Derive helpers are not in scope when resolving derives in the same container.
1516 Scope::DeriveHelpers(expn_id) => {
1517 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1519 Scope::DeriveHelpersCompat => true,
1520 Scope::MacroRules(..) => true,
1521 Scope::CrateRoot => true,
1522 Scope::Module(..) => true,
1523 Scope::RegisteredAttrs => use_prelude,
1524 Scope::MacroUsePrelude => use_prelude || rust_2015,
1525 Scope::BuiltinAttrs => true,
1526 Scope::ExternPrelude => use_prelude || is_absolute_path,
1527 Scope::ToolPrelude => use_prelude,
1528 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1529 Scope::BuiltinTypes => true,
1533 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1534 return break_result;
1538 scope = match scope {
1539 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1540 // Derive helpers are not visible to code generated by bang or derive macros.
1541 let expn_data = expn_id.expn_data();
1542 match expn_data.kind {
1544 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1545 Scope::DeriveHelpersCompat
1547 _ => Scope::DeriveHelpers(expn_data.parent),
1550 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1551 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1552 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope {
1553 MacroRulesScope::Binding(binding) => {
1554 Scope::MacroRules(binding.parent_macro_rules_scope)
1556 MacroRulesScope::Invocation(invoc_id) => Scope::MacroRules(
1557 self.output_macro_rules_scopes
1560 .unwrap_or(self.invocation_parent_scopes[&invoc_id].macro_rules),
1562 MacroRulesScope::Empty => Scope::Module(module),
1564 Scope::CrateRoot => match ns {
1566 ident.span.adjust(ExpnId::root());
1567 Scope::ExternPrelude
1569 ValueNS | MacroNS => break,
1571 Scope::Module(module) => {
1572 use_prelude = !module.no_implicit_prelude;
1573 match self.hygienic_lexical_parent(module, &mut ident.span) {
1574 Some(parent_module) => Scope::Module(parent_module),
1576 ident.span.adjust(ExpnId::root());
1578 TypeNS => Scope::ExternPrelude,
1579 ValueNS => Scope::StdLibPrelude,
1580 MacroNS => Scope::RegisteredAttrs,
1585 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1586 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1587 Scope::BuiltinAttrs => break, // nowhere else to search
1588 Scope::ExternPrelude if is_absolute_path => break,
1589 Scope::ExternPrelude => Scope::ToolPrelude,
1590 Scope::ToolPrelude => Scope::StdLibPrelude,
1591 Scope::StdLibPrelude => match ns {
1592 TypeNS => Scope::BuiltinTypes,
1593 ValueNS => break, // nowhere else to search
1594 MacroNS => Scope::BuiltinAttrs,
1596 Scope::BuiltinTypes => break, // nowhere else to search
1603 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1604 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1605 /// `ident` in the first scope that defines it (or None if no scopes define it).
1607 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1608 /// the items are defined in the block. For example,
1611 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1614 /// g(); // This resolves to the local variable `g` since it shadows the item.
1618 /// Invariant: This must only be called during main resolution, not during
1619 /// import resolution.
1620 fn resolve_ident_in_lexical_scope(
1624 parent_scope: &ParentScope<'a>,
1625 record_used_id: Option<NodeId>,
1628 ) -> Option<LexicalScopeBinding<'a>> {
1629 assert!(ns == TypeNS || ns == ValueNS);
1630 if ident.name == kw::Invalid {
1631 return Some(LexicalScopeBinding::Res(Res::Err));
1633 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1634 // FIXME(jseyfried) improve `Self` hygiene
1635 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1636 (empty_span, empty_span)
1637 } else if ns == TypeNS {
1638 let normalized_span = ident.span.normalize_to_macros_2_0();
1639 (normalized_span, normalized_span)
1641 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1643 ident.span = general_span;
1644 let normalized_ident = Ident { span: normalized_span, ..ident };
1646 // Walk backwards up the ribs in scope.
1647 let record_used = record_used_id.is_some();
1648 let mut module = self.graph_root;
1649 for i in (0..ribs.len()).rev() {
1650 debug!("walk rib\n{:?}", ribs[i].bindings);
1651 // Use the rib kind to determine whether we are resolving parameters
1652 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1653 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1654 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1655 // The ident resolves to a type parameter or local variable.
1656 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1666 module = match ribs[i].kind {
1667 ModuleRibKind(module) => module,
1668 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1669 // If an invocation of this macro created `ident`, give up on `ident`
1670 // and switch to `ident`'s source from the macro definition.
1671 ident.span.remove_mark();
1677 let item = self.resolve_ident_in_module_unadjusted(
1678 ModuleOrUniformRoot::Module(module),
1685 if let Ok(binding) = item {
1686 // The ident resolves to an item.
1687 return Some(LexicalScopeBinding::Item(binding));
1691 ModuleKind::Block(..) => {} // We can see through blocks
1696 ident = normalized_ident;
1697 let mut poisoned = None;
1699 let opt_module = if let Some(node_id) = record_used_id {
1700 self.hygienic_lexical_parent_with_compatibility_fallback(
1707 self.hygienic_lexical_parent(module, &mut ident.span)
1709 module = unwrap_or!(opt_module, break);
1710 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1711 let result = self.resolve_ident_in_module_unadjusted(
1712 ModuleOrUniformRoot::Module(module),
1715 adjusted_parent_scope,
1722 if let Some(node_id) = poisoned {
1723 self.lint_buffer.buffer_lint_with_diagnostic(
1724 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1727 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1728 BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
1731 return Some(LexicalScopeBinding::Item(binding));
1733 Err(Determined) => continue,
1734 Err(Undetermined) => {
1735 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1740 if !module.no_implicit_prelude {
1741 ident.span.adjust(ExpnId::root());
1743 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1744 return Some(LexicalScopeBinding::Item(binding));
1746 if let Some(ident) = self.registered_tools.get(&ident) {
1748 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1749 .to_name_binding(self.arenas);
1750 return Some(LexicalScopeBinding::Item(binding));
1753 if let Some(prelude) = self.prelude {
1754 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1755 ModuleOrUniformRoot::Module(prelude),
1762 return Some(LexicalScopeBinding::Item(binding));
1768 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1770 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1771 .to_name_binding(self.arenas);
1772 return Some(LexicalScopeBinding::Item(binding));
1779 fn hygienic_lexical_parent(
1783 ) -> Option<Module<'a>> {
1784 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1785 return Some(self.macro_def_scope(span.remove_mark()));
1788 if let ModuleKind::Block(..) = module.kind {
1789 return Some(module.parent.unwrap().nearest_item_scope());
1795 fn hygienic_lexical_parent_with_compatibility_fallback(
1800 poisoned: &mut Option<NodeId>,
1801 ) -> Option<Module<'a>> {
1802 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1806 // We need to support the next case under a deprecation warning
1809 // ---- begin: this comes from a proc macro derive
1810 // mod implementation_details {
1811 // // Note that `MyStruct` is not in scope here.
1812 // impl SomeTrait for MyStruct { ... }
1816 // So we have to fall back to the module's parent during lexical resolution in this case.
1817 if let Some(parent) = module.parent {
1818 // Inner module is inside the macro, parent module is outside of the macro.
1819 if module.expansion != parent.expansion
1820 && module.expansion.is_descendant_of(parent.expansion)
1822 // The macro is a proc macro derive
1823 if let Some(&def_id) = self.macro_defs.get(&module.expansion) {
1824 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1825 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1826 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1827 *poisoned = Some(node_id);
1828 return module.parent;
1839 fn resolve_ident_in_module(
1841 module: ModuleOrUniformRoot<'a>,
1844 parent_scope: &ParentScope<'a>,
1847 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1848 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1849 .map_err(|(determinacy, _)| determinacy)
1852 fn resolve_ident_in_module_ext(
1854 module: ModuleOrUniformRoot<'a>,
1857 parent_scope: &ParentScope<'a>,
1860 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1861 let tmp_parent_scope;
1862 let mut adjusted_parent_scope = parent_scope;
1864 ModuleOrUniformRoot::Module(m) => {
1865 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
1867 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1868 adjusted_parent_scope = &tmp_parent_scope;
1871 ModuleOrUniformRoot::ExternPrelude => {
1872 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
1874 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1878 self.resolve_ident_in_module_unadjusted_ext(
1882 adjusted_parent_scope,
1889 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1890 let mut ctxt = ident.span.ctxt();
1891 let mark = if ident.name == kw::DollarCrate {
1892 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1893 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1894 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
1895 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
1896 // definitions actually produced by `macro` and `macro` definitions produced by
1897 // `macro_rules!`, but at least such configurations are not stable yet.
1898 ctxt = ctxt.normalize_to_macro_rules();
1899 let mut iter = ctxt.marks().into_iter().rev().peekable();
1900 let mut result = None;
1901 // Find the last opaque mark from the end if it exists.
1902 while let Some(&(mark, transparency)) = iter.peek() {
1903 if transparency == Transparency::Opaque {
1904 result = Some(mark);
1910 // Then find the last semi-transparent mark from the end if it exists.
1911 for (mark, transparency) in iter {
1912 if transparency == Transparency::SemiTransparent {
1913 result = Some(mark);
1920 ctxt = ctxt.normalize_to_macros_2_0();
1921 ctxt.adjust(ExpnId::root())
1923 let module = match mark {
1924 Some(def) => self.macro_def_scope(def),
1925 None => return self.graph_root,
1927 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1930 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1931 let mut module = self.get_module(module.normal_ancestor_id);
1932 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
1933 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1934 module = self.get_module(parent.normal_ancestor_id);
1942 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1943 parent_scope: &ParentScope<'a>,
1946 crate_lint: CrateLint,
1947 ) -> PathResult<'a> {
1948 self.resolve_path_with_ribs(
1959 fn resolve_path_with_ribs(
1962 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1963 parent_scope: &ParentScope<'a>,
1966 crate_lint: CrateLint,
1967 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1968 ) -> PathResult<'a> {
1969 let mut module = None;
1970 let mut allow_super = true;
1971 let mut second_binding = None;
1974 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
1975 path_span={:?}, crate_lint={:?})",
1976 path, opt_ns, record_used, path_span, crate_lint,
1979 for (i, &Segment { ident, id }) in path.iter().enumerate() {
1980 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
1981 let record_segment_res = |this: &mut Self, res| {
1983 if let Some(id) = id {
1984 if !this.partial_res_map.contains_key(&id) {
1985 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
1986 this.record_partial_res(id, PartialRes::new(res));
1992 let is_last = i == path.len() - 1;
1993 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1994 let name = ident.name;
1996 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
1999 if allow_super && name == kw::Super {
2000 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2001 let self_module = match i {
2002 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2004 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2008 if let Some(self_module) = self_module {
2009 if let Some(parent) = self_module.parent {
2010 module = Some(ModuleOrUniformRoot::Module(
2011 self.resolve_self(&mut ctxt, parent),
2016 let msg = "there are too many leading `super` keywords".to_string();
2017 return PathResult::Failed {
2021 is_error_from_last_segment: false,
2025 if name == kw::SelfLower {
2026 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2027 module = Some(ModuleOrUniformRoot::Module(
2028 self.resolve_self(&mut ctxt, parent_scope.module),
2032 if name == kw::PathRoot && ident.span.rust_2018() {
2033 module = Some(ModuleOrUniformRoot::ExternPrelude);
2036 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2037 // `::a::b` from 2015 macro on 2018 global edition
2038 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2041 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2042 // `::a::b`, `crate::a::b` or `$crate::a::b`
2043 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2049 // Report special messages for path segment keywords in wrong positions.
2050 if ident.is_path_segment_keyword() && i != 0 {
2051 let name_str = if name == kw::PathRoot {
2052 "crate root".to_string()
2054 format!("`{}`", name)
2056 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2057 format!("global paths cannot start with {}", name_str)
2059 format!("{} in paths can only be used in start position", name_str)
2061 return PathResult::Failed {
2065 is_error_from_last_segment: false,
2069 enum FindBindingResult<'a> {
2070 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2071 PathResult(PathResult<'a>),
2073 let find_binding_in_ns = |this: &mut Self, ns| {
2074 let binding = if let Some(module) = module {
2075 this.resolve_ident_in_module(
2083 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2084 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2085 this.early_resolve_ident_in_lexical_scope(
2094 let record_used_id = if record_used {
2095 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2099 match this.resolve_ident_in_lexical_scope(
2107 // we found a locally-imported or available item/module
2108 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2109 // we found a local variable or type param
2110 Some(LexicalScopeBinding::Res(res))
2111 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2113 record_segment_res(this, res);
2114 return FindBindingResult::PathResult(PathResult::NonModule(
2115 PartialRes::with_unresolved_segments(res, path.len() - 1),
2118 _ => Err(Determinacy::determined(record_used)),
2121 FindBindingResult::Binding(binding)
2123 let binding = match find_binding_in_ns(self, ns) {
2124 FindBindingResult::PathResult(x) => return x,
2125 FindBindingResult::Binding(binding) => binding,
2130 second_binding = Some(binding);
2132 let res = binding.res();
2133 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2134 if let Some(next_module) = binding.module() {
2135 module = Some(ModuleOrUniformRoot::Module(next_module));
2136 record_segment_res(self, res);
2137 } else if res == Res::ToolMod && i + 1 != path.len() {
2138 if binding.is_import() {
2142 "cannot use a tool module through an import",
2144 .span_note(binding.span, "the tool module imported here")
2147 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2148 return PathResult::NonModule(PartialRes::new(res));
2149 } else if res == Res::Err {
2150 return PathResult::NonModule(PartialRes::new(Res::Err));
2151 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2152 self.lint_if_path_starts_with_module(
2158 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2163 let label = format!(
2164 "`{}` is {} {}, not a module",
2170 return PathResult::Failed {
2174 is_error_from_last_segment: is_last,
2178 Err(Undetermined) => return PathResult::Indeterminate,
2179 Err(Determined) => {
2180 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2181 if opt_ns.is_some() && !module.is_normal() {
2182 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2183 module.res().unwrap(),
2188 let module_res = match module {
2189 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2192 let (label, suggestion) = if module_res == self.graph_root.res() {
2193 let is_mod = |res| match res {
2194 Res::Def(DefKind::Mod, _) => true,
2197 let mut candidates = self.lookup_import_candidates(ident, TypeNS, is_mod);
2198 candidates.sort_by_cached_key(|c| {
2199 (c.path.segments.len(), pprust::path_to_string(&c.path))
2201 if let Some(candidate) = candidates.get(0) {
2203 String::from("unresolved import"),
2205 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2206 String::from("a similar path exists"),
2207 Applicability::MaybeIncorrect,
2211 (format!("maybe a missing crate `{}`?", ident), None)
2214 (format!("use of undeclared type or module `{}`", ident), None)
2217 format!("could not find `{}` in `{}`", ident, path[i - 1].ident);
2218 if ns == TypeNS || ns == ValueNS {
2219 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2220 if let FindBindingResult::Binding(Ok(binding)) =
2221 find_binding_in_ns(self, ns_to_try)
2223 let mut found = |what| {
2225 "expected {}, found {} `{}` in `{}`",
2232 if binding.module().is_some() {
2235 match binding.res() {
2236 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2237 _ => found(ns_to_try.descr()),
2244 return PathResult::Failed {
2248 is_error_from_last_segment: is_last,
2254 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2256 PathResult::Module(match module {
2257 Some(module) => module,
2258 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2259 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2263 fn lint_if_path_starts_with_module(
2265 crate_lint: CrateLint,
2268 second_binding: Option<&NameBinding<'_>>,
2270 let (diag_id, diag_span) = match crate_lint {
2271 CrateLint::No => return,
2272 CrateLint::SimplePath(id) => (id, path_span),
2273 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2274 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2277 let first_name = match path.get(0) {
2278 // In the 2018 edition this lint is a hard error, so nothing to do
2279 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2283 // We're only interested in `use` paths which should start with
2284 // `{{root}}` currently.
2285 if first_name != kw::PathRoot {
2290 // If this import looks like `crate::...` it's already good
2291 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2292 // Otherwise go below to see if it's an extern crate
2294 // If the path has length one (and it's `PathRoot` most likely)
2295 // then we don't know whether we're gonna be importing a crate or an
2296 // item in our crate. Defer this lint to elsewhere
2300 // If the first element of our path was actually resolved to an
2301 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2302 // warning, this looks all good!
2303 if let Some(binding) = second_binding {
2304 if let NameBindingKind::Import { import, .. } = binding.kind {
2305 // Careful: we still want to rewrite paths from renamed extern crates.
2306 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2312 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2313 self.lint_buffer.buffer_lint_with_diagnostic(
2314 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2317 "absolute paths must start with `self`, `super`, \
2318 `crate`, or an external crate name in the 2018 edition",
2323 // Validate a local resolution (from ribs).
2324 fn validate_res_from_ribs(
2331 all_ribs: &[Rib<'a>],
2333 debug!("validate_res_from_ribs({:?})", res);
2334 let ribs = &all_ribs[rib_index + 1..];
2336 // An invalid forward use of a type parameter from a previous default.
2337 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2339 let res_error = if rib_ident.name == kw::SelfUpper {
2340 ResolutionError::SelfInTyParamDefault
2342 ResolutionError::ForwardDeclaredTyParam
2344 self.report_error(span, res_error);
2346 assert_eq!(res, Res::Err);
2352 use ResolutionError::*;
2353 let mut res_err = None;
2359 | MacroDefinition(..)
2360 | ForwardTyParamBanRibKind => {
2361 // Nothing to do. Continue.
2363 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2364 // This was an attempt to access an upvar inside a
2365 // named function item. This is not allowed, so we
2368 // We don't immediately trigger a resolve error, because
2369 // we want certain other resolution errors (namely those
2370 // emitted for `ConstantItemRibKind` below) to take
2372 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2375 ConstantItemRibKind => {
2376 // Still doesn't deal with upvars
2378 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2384 if let Some(res_err) = res_err {
2385 self.report_error(span, res_err);
2389 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2391 let has_generic_params = match rib.kind {
2395 | MacroDefinition(..)
2396 | ForwardTyParamBanRibKind
2397 | ConstantItemRibKind => {
2398 // Nothing to do. Continue.
2401 // This was an attempt to use a type parameter outside its scope.
2402 ItemRibKind(has_generic_params) => has_generic_params,
2403 FnItemRibKind => HasGenericParams::Yes,
2409 ResolutionError::GenericParamsFromOuterFunction(
2418 Res::Def(DefKind::ConstParam, _) => {
2419 let mut ribs = ribs.iter().peekable();
2420 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2421 // When declaring const parameters inside function signatures, the first rib
2422 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2423 // (spuriously) conflicting with the const param.
2427 let has_generic_params = match rib.kind {
2428 ItemRibKind(has_generic_params) => has_generic_params,
2429 FnItemRibKind => HasGenericParams::Yes,
2433 // This was an attempt to use a const parameter outside its scope.
2437 ResolutionError::GenericParamsFromOuterFunction(
2451 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2452 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2453 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2454 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2458 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2459 vis.is_accessible_from(module.normal_ancestor_id, self)
2462 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2463 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2464 if !ptr::eq(module, old_module) {
2465 span_bug!(binding.span, "parent module is reset for binding");
2470 fn disambiguate_macro_rules_vs_modularized(
2472 macro_rules: &'a NameBinding<'a>,
2473 modularized: &'a NameBinding<'a>,
2475 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2476 // is disambiguated to mitigate regressions from macro modularization.
2477 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2479 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2480 self.binding_parent_modules.get(&PtrKey(modularized)),
2482 (Some(macro_rules), Some(modularized)) => {
2483 macro_rules.normal_ancestor_id == modularized.normal_ancestor_id
2484 && modularized.is_ancestor_of(macro_rules)
2490 fn report_errors(&mut self, krate: &Crate) {
2491 self.report_with_use_injections(krate);
2493 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2494 let msg = "macro-expanded `macro_export` macros from the current crate \
2495 cannot be referred to by absolute paths";
2496 self.lint_buffer.buffer_lint_with_diagnostic(
2497 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2501 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2505 for ambiguity_error in &self.ambiguity_errors {
2506 self.report_ambiguity_error(ambiguity_error);
2509 let mut reported_spans = FxHashSet::default();
2510 for error in &self.privacy_errors {
2511 if reported_spans.insert(error.dedup_span) {
2512 self.report_privacy_error(error);
2517 fn report_with_use_injections(&mut self, krate: &Crate) {
2518 for UseError { mut err, candidates, node_id, better, suggestion } in
2519 self.use_injections.drain(..)
2521 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
2522 if !candidates.is_empty() {
2523 diagnostics::show_candidates(&mut err, span, &candidates, better, found_use);
2524 } else if let Some((span, msg, sugg, appl)) = suggestion {
2525 err.span_suggestion(span, msg, sugg, appl);
2531 fn report_conflict<'b>(
2536 new_binding: &NameBinding<'b>,
2537 old_binding: &NameBinding<'b>,
2539 // Error on the second of two conflicting names
2540 if old_binding.span.lo() > new_binding.span.lo() {
2541 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2544 let container = match parent.kind {
2545 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2546 ModuleKind::Block(..) => "block",
2549 let old_noun = match old_binding.is_import() {
2551 false => "definition",
2554 let new_participle = match new_binding.is_import() {
2560 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2562 if let Some(s) = self.name_already_seen.get(&name) {
2568 let old_kind = match (ns, old_binding.module()) {
2569 (ValueNS, _) => "value",
2570 (MacroNS, _) => "macro",
2571 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2572 (TypeNS, Some(module)) if module.is_normal() => "module",
2573 (TypeNS, Some(module)) if module.is_trait() => "trait",
2574 (TypeNS, _) => "type",
2577 let msg = format!("the name `{}` is defined multiple times", name);
2579 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2580 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2581 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2582 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2583 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2585 _ => match (old_binding.is_import(), new_binding.is_import()) {
2586 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2587 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2588 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2593 "`{}` must be defined only once in the {} namespace of this {}",
2599 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2601 self.session.source_map().guess_head_span(old_binding.span),
2602 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2605 // See https://github.com/rust-lang/rust/issues/32354
2606 use NameBindingKind::Import;
2607 let import = match (&new_binding.kind, &old_binding.kind) {
2608 // If there are two imports where one or both have attributes then prefer removing the
2609 // import without attributes.
2610 (Import { import: new, .. }, Import { import: old, .. })
2612 !new_binding.span.is_dummy()
2613 && !old_binding.span.is_dummy()
2614 && (new.has_attributes || old.has_attributes)
2617 if old.has_attributes {
2618 Some((new, new_binding.span, true))
2620 Some((old, old_binding.span, true))
2623 // Otherwise prioritize the new binding.
2624 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
2625 Some((import, new_binding.span, other.is_import()))
2627 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
2628 Some((import, old_binding.span, other.is_import()))
2633 // Check if the target of the use for both bindings is the same.
2634 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2635 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2637 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2638 // Only suggest removing an import if both bindings are to the same def, if both spans
2639 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2640 // been introduced by a item.
2641 let should_remove_import = duplicate
2643 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2646 Some((import, span, true)) if should_remove_import && import.is_nested() => {
2647 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
2649 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
2650 // Simple case - remove the entire import. Due to the above match arm, this can
2651 // only be a single use so just remove it entirely.
2652 err.tool_only_span_suggestion(
2653 import.use_span_with_attributes,
2654 "remove unnecessary import",
2656 Applicability::MaybeIncorrect,
2659 Some((import, span, _)) => {
2660 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
2666 self.name_already_seen.insert(name, span);
2669 /// This function adds a suggestion to change the binding name of a new import that conflicts
2670 /// with an existing import.
2672 /// ```text,ignore (diagnostic)
2673 /// help: you can use `as` to change the binding name of the import
2675 /// LL | use foo::bar as other_bar;
2676 /// | ^^^^^^^^^^^^^^^^^^^^^
2678 fn add_suggestion_for_rename_of_use(
2680 err: &mut DiagnosticBuilder<'_>,
2682 import: &Import<'_>,
2685 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2686 format!("Other{}", name)
2688 format!("other_{}", name)
2691 let mut suggestion = None;
2693 ImportKind::Single { type_ns_only: true, .. } => {
2694 suggestion = Some(format!("self as {}", suggested_name))
2696 ImportKind::Single { source, .. } => {
2698 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2700 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2701 if pos <= snippet.len() {
2702 suggestion = Some(format!(
2706 if snippet.ends_with(';') { ";" } else { "" }
2712 ImportKind::ExternCrate { source, target, .. } => {
2713 suggestion = Some(format!(
2714 "extern crate {} as {};",
2715 source.unwrap_or(target.name),
2719 _ => unreachable!(),
2722 let rename_msg = "you can use `as` to change the binding name of the import";
2723 if let Some(suggestion) = suggestion {
2724 err.span_suggestion(
2728 Applicability::MaybeIncorrect,
2731 err.span_label(binding_span, rename_msg);
2735 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2736 /// nested. In the following example, this function will be invoked to remove the `a` binding
2737 /// in the second use statement:
2739 /// ```ignore (diagnostic)
2740 /// use issue_52891::a;
2741 /// use issue_52891::{d, a, e};
2744 /// The following suggestion will be added:
2746 /// ```ignore (diagnostic)
2747 /// use issue_52891::{d, a, e};
2748 /// ^-- help: remove unnecessary import
2751 /// If the nested use contains only one import then the suggestion will remove the entire
2754 /// It is expected that the provided import is nested - this isn't checked by the
2755 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2756 /// as characters expected by span manipulations won't be present.
2757 fn add_suggestion_for_duplicate_nested_use(
2759 err: &mut DiagnosticBuilder<'_>,
2760 import: &Import<'_>,
2763 assert!(import.is_nested());
2764 let message = "remove unnecessary import";
2766 // Two examples will be used to illustrate the span manipulations we're doing:
2768 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
2769 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
2770 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
2771 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
2773 let (found_closing_brace, span) =
2774 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
2776 // If there was a closing brace then identify the span to remove any trailing commas from
2777 // previous imports.
2778 if found_closing_brace {
2779 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
2780 err.tool_only_span_suggestion(
2784 Applicability::MaybeIncorrect,
2787 // Remove the entire line if we cannot extend the span back, this indicates a
2788 // `issue_52891::{self}` case.
2789 err.span_suggestion(
2790 import.use_span_with_attributes,
2793 Applicability::MaybeIncorrect,
2800 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
2803 fn extern_prelude_get(
2807 ) -> Option<&'a NameBinding<'a>> {
2808 if ident.is_path_segment_keyword() {
2809 // Make sure `self`, `super` etc produce an error when passed to here.
2812 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
2813 if let Some(binding) = entry.extern_crate_item {
2814 if !speculative && entry.introduced_by_item {
2815 self.record_use(ident, TypeNS, binding, false);
2819 let crate_id = if !speculative {
2820 self.crate_loader.process_path_extern(ident.name, ident.span)
2822 self.crate_loader.maybe_process_path_extern(ident.name, ident.span)?
2824 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2826 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
2827 .to_name_binding(self.arenas),
2833 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
2834 /// isn't something that can be returned because it can't be made to live that long,
2835 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
2836 /// just that an error occurred.
2837 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
2838 pub fn resolve_str_path_error(
2844 ) -> Result<(ast::Path, Res), ()> {
2845 let path = if path_str.starts_with("::") {
2848 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
2849 .chain(path_str.split("::").skip(1).map(Ident::from_str))
2850 .map(|i| self.new_ast_path_segment(i))
2858 .map(Ident::from_str)
2859 .map(|i| self.new_ast_path_segment(i))
2863 let module = self.block_map.get(&module_id).copied().unwrap_or_else(|| {
2864 let def_id = self.definitions.local_def_id(module_id);
2865 self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
2867 let parent_scope = &ParentScope::module(module);
2868 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
2872 // Resolve a path passed from rustdoc or HIR lowering.
2873 fn resolve_ast_path(
2877 parent_scope: &ParentScope<'a>,
2878 ) -> Result<Res, (Span, ResolutionError<'a>)> {
2879 match self.resolve_path(
2880 &Segment::from_path(path),
2887 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
2888 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
2889 Ok(path_res.base_res())
2891 PathResult::NonModule(..) => Err((
2893 ResolutionError::FailedToResolve {
2894 label: String::from("type-relative paths are not supported in this context"),
2898 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
2899 PathResult::Failed { span, label, suggestion, .. } => {
2900 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
2905 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
2906 let mut seg = ast::PathSegment::from_ident(ident);
2907 seg.id = self.next_node_id();
2912 pub fn graph_root(&self) -> Module<'a> {
2917 pub fn all_macros(&self) -> &FxHashMap<Name, Res> {
2922 fn names_to_string(names: &[Name]) -> String {
2923 let mut result = String::new();
2924 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
2926 result.push_str("::");
2928 if Ident::with_dummy_span(*name).is_raw_guess() {
2929 result.push_str("r#");
2931 result.push_str(&name.as_str());
2936 fn path_names_to_string(path: &Path) -> String {
2937 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
2940 /// A somewhat inefficient routine to obtain the name of a module.
2941 fn module_to_string(module: Module<'_>) -> Option<String> {
2942 let mut names = Vec::new();
2944 fn collect_mod(names: &mut Vec<Name>, module: Module<'_>) {
2945 if let ModuleKind::Def(.., name) = module.kind {
2946 if let Some(parent) = module.parent {
2948 collect_mod(names, parent);
2951 names.push(Name::intern("<opaque>"));
2952 collect_mod(names, module.parent.unwrap());
2955 collect_mod(&mut names, module);
2957 if names.is_empty() {
2961 Some(names_to_string(&names))
2964 #[derive(Copy, Clone, Debug)]
2966 /// Do not issue the lint.
2969 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
2970 /// In this case, we can take the span of that path.
2973 /// This lint comes from a `use` statement. In this case, what we
2974 /// care about really is the *root* `use` statement; e.g., if we
2975 /// have nested things like `use a::{b, c}`, we care about the
2977 UsePath { root_id: NodeId, root_span: Span },
2979 /// This is the "trait item" from a fully qualified path. For example,
2980 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
2981 /// The `path_span` is the span of the to the trait itself (`X::Y`).
2982 QPathTrait { qpath_id: NodeId, qpath_span: Span },
2986 fn node_id(&self) -> Option<NodeId> {
2988 CrateLint::No => None,
2989 CrateLint::SimplePath(id)
2990 | CrateLint::UsePath { root_id: id, .. }
2991 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
2996 pub fn provide(providers: &mut Providers<'_>) {
2997 late::lifetimes::provide(providers);