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 names are resolved here as well.
7 //! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
8 //! Lifetime names are resolved in `librustc/middle/resolve_lifetime.rs`.
10 // ignore-tidy-filelength
12 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
13 #![feature(bool_to_option)]
14 #![feature(crate_visibility_modifier)]
15 #![feature(label_break_value)]
17 #![recursion_limit = "256"]
19 pub use rustc_hir::def::{Namespace, PerNS};
23 use errors::{Applicability, DiagnosticBuilder};
24 use rustc::hir::exports::ExportMap;
25 use rustc::hir::map::Definitions;
27 use rustc::middle::cstore::{CrateStore, MetadataLoaderDyn};
28 use rustc::session::Session;
30 use rustc::ty::query::Providers;
31 use rustc::ty::{self, DefIdTree, ResolverOutputs};
32 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
33 use rustc_data_structures::ptr_key::PtrKey;
34 use rustc_data_structures::sync::Lrc;
35 use rustc_expand::base::SyntaxExtension;
36 use rustc_hir::def::Namespace::*;
37 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
38 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
39 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
40 use rustc_hir::{GlobMap, TraitMap};
41 use rustc_metadata::creader::{CStore, CrateLoader};
42 use rustc_session::node_id::{NodeMap, NodeSet};
43 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
44 use rustc_span::source_map::Spanned;
45 use rustc_span::symbol::{kw, sym};
46 use rustc_span::{Span, DUMMY_SP};
47 use syntax::ast::{self, FloatTy, Ident, IntTy, Name, NodeId, UintTy};
48 use syntax::ast::{Crate, CRATE_NODE_ID};
49 use syntax::ast::{ItemKind, Path};
51 use syntax::print::pprust;
52 use syntax::visit::{self, Visitor};
53 use syntax::{struct_span_err, unwrap_or};
56 use std::cell::{Cell, RefCell};
57 use std::collections::BTreeSet;
58 use std::{cmp, fmt, iter, ptr};
60 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
61 use diagnostics::{ImportSuggestion, Suggestion};
62 use imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver, NameResolution};
63 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
64 use macros::{LegacyBinding, LegacyScope};
66 use rustc_error_codes::*;
68 type Res = def::Res<NodeId>;
70 mod build_reduced_graph;
84 #[derive(Copy, Clone, PartialEq, Debug)]
85 pub enum Determinacy {
91 fn determined(determined: bool) -> Determinacy {
92 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
96 /// A specific scope in which a name can be looked up.
97 /// This enum is currently used only for early resolution (imports and macros),
98 /// but not for late resolution yet.
99 #[derive(Clone, Copy)]
101 DeriveHelpers(ExpnId),
103 MacroRules(LegacyScope<'a>),
115 /// Names from different contexts may want to visit different subsets of all specific scopes
116 /// with different restrictions when looking up the resolution.
117 /// This enum is currently used only for early resolution (imports and macros),
118 /// but not for late resolution yet.
120 /// All scopes with the given namespace.
121 All(Namespace, /*is_import*/ bool),
122 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
123 AbsolutePath(Namespace),
124 /// All scopes with macro namespace and the given macro kind restriction.
128 /// Everything you need to know about a name's location to resolve it.
129 /// Serves as a starting point for the scope visitor.
130 /// This struct is currently used only for early resolution (imports and macros),
131 /// but not for late resolution yet.
132 #[derive(Clone, Copy, Debug)]
133 pub struct ParentScope<'a> {
136 legacy: LegacyScope<'a>,
137 derives: &'a [ast::Path],
140 impl<'a> ParentScope<'a> {
141 /// Creates a parent scope with the passed argument used as the module scope component,
142 /// and other scope components set to default empty values.
143 pub fn module(module: Module<'a>) -> ParentScope<'a> {
144 ParentScope { module, expansion: ExpnId::root(), legacy: LegacyScope::Empty, derives: &[] }
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 item(self) -> Option<&'a NameBinding<'a>> {
334 LexicalScopeBinding::Item(binding) => Some(binding),
339 fn res(self) -> Res {
341 LexicalScopeBinding::Item(binding) => binding.res(),
342 LexicalScopeBinding::Res(res) => res,
347 #[derive(Copy, Clone, Debug)]
348 enum ModuleOrUniformRoot<'a> {
352 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
353 CrateRootAndExternPrelude,
355 /// Virtual module that denotes resolution in extern prelude.
356 /// Used for paths starting with `::` on 2018 edition.
359 /// Virtual module that denotes resolution in current scope.
360 /// Used only for resolving single-segment imports. The reason it exists is that import paths
361 /// are always split into two parts, the first of which should be some kind of module.
365 impl ModuleOrUniformRoot<'_> {
366 fn same_def(lhs: Self, rhs: Self) -> bool {
368 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
369 lhs.def_id() == rhs.def_id()
372 ModuleOrUniformRoot::CrateRootAndExternPrelude,
373 ModuleOrUniformRoot::CrateRootAndExternPrelude,
375 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
376 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
382 #[derive(Clone, Debug)]
383 enum PathResult<'a> {
384 Module(ModuleOrUniformRoot<'a>),
385 NonModule(PartialRes),
390 suggestion: Option<Suggestion>,
391 is_error_from_last_segment: bool,
396 /// An anonymous module; e.g., just a block.
401 /// { // This is an anonymous module
402 /// f(); // This resolves to (2) as we are inside the block.
405 /// f(); // Resolves to (1)
409 /// Any module with a name.
413 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
414 /// * A trait or an enum (it implicitly contains associated types, methods and variant
416 Def(DefKind, DefId, Name),
420 /// Get name of the module.
421 pub fn name(&self) -> Option<Name> {
423 ModuleKind::Block(..) => None,
424 ModuleKind::Def(.., name) => Some(*name),
429 /// A key that identifies a binding in a given `Module`.
431 /// Multiple bindings in the same module can have the same key (in a valid
432 /// program) if all but one of them come from glob imports.
433 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
435 /// The identifier for the binding, aways the `modern` version of the
439 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
440 /// `_` in the expanded AST that introduced this binding.
444 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
446 /// One node in the tree of modules.
447 pub struct ModuleData<'a> {
448 parent: Option<Module<'a>>,
451 // The def id of the closest normal module (`mod`) ancestor (including this module).
452 normal_ancestor_id: DefId,
454 // Mapping between names and their (possibly in-progress) resolutions in this module.
455 // Resolutions in modules from other crates are not populated until accessed.
456 lazy_resolutions: Resolutions<'a>,
457 // True if this is a module from other crate that needs to be populated on access.
458 populate_on_access: Cell<bool>,
460 // Macro invocations that can expand into items in this module.
461 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
463 no_implicit_prelude: bool,
465 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
466 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
468 // Used to memoize the traits in this module for faster searches through all traits in scope.
469 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
471 /// Span of the module itself. Used for error reporting.
477 type Module<'a> = &'a ModuleData<'a>;
479 impl<'a> ModuleData<'a> {
481 parent: Option<Module<'a>>,
483 normal_ancestor_id: DefId,
491 lazy_resolutions: Default::default(),
492 populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
493 unexpanded_invocations: Default::default(),
494 no_implicit_prelude: false,
495 glob_importers: RefCell::new(Vec::new()),
496 globs: RefCell::new(Vec::new()),
497 traits: RefCell::new(None),
503 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
505 R: AsMut<Resolver<'a>>,
506 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
508 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
509 name_resolution.borrow().binding.map(|binding| f(resolver, key.ident, key.ns, binding));
513 fn res(&self) -> Option<Res> {
515 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
520 fn def_id(&self) -> Option<DefId> {
522 ModuleKind::Def(_, def_id, _) => Some(def_id),
527 // `self` resolves to the first module ancestor that `is_normal`.
528 fn is_normal(&self) -> bool {
530 ModuleKind::Def(DefKind::Mod, _, _) => true,
535 fn is_trait(&self) -> bool {
537 ModuleKind::Def(DefKind::Trait, _, _) => true,
542 fn nearest_item_scope(&'a self) -> Module<'a> {
544 ModuleKind::Def(DefKind::Enum, ..) | ModuleKind::Def(DefKind::Trait, ..) => {
545 self.parent.expect("enum or trait module without a parent")
551 fn is_ancestor_of(&self, mut other: &Self) -> bool {
552 while !ptr::eq(self, other) {
553 if let Some(parent) = other.parent {
563 impl<'a> fmt::Debug for ModuleData<'a> {
564 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
565 write!(f, "{:?}", self.res())
569 /// Records a possibly-private value, type, or module definition.
570 #[derive(Clone, Debug)]
571 pub struct NameBinding<'a> {
572 kind: NameBindingKind<'a>,
573 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
579 pub trait ToNameBinding<'a> {
580 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
583 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
584 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
589 #[derive(Clone, Debug)]
590 enum NameBindingKind<'a> {
591 Res(Res, /* is_macro_export */ bool),
593 Import { binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>, used: Cell<bool> },
596 impl<'a> NameBindingKind<'a> {
597 /// Is this a name binding of a import?
598 fn is_import(&self) -> bool {
600 NameBindingKind::Import { .. } => true,
606 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
608 struct UseError<'a> {
609 err: DiagnosticBuilder<'a>,
610 /// Attach `use` statements for these candidates.
611 candidates: Vec<ImportSuggestion>,
612 /// The `NodeId` of the module to place the use-statements in.
614 /// Whether the diagnostic should state that it's "better".
618 #[derive(Clone, Copy, PartialEq, Debug)]
631 fn descr(self) -> &'static str {
633 AmbiguityKind::Import => "name vs any other name during import resolution",
634 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
635 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
636 AmbiguityKind::LegacyVsModern => "`macro_rules` vs non-`macro_rules` from other module",
637 AmbiguityKind::GlobVsOuter => {
638 "glob import vs any other name from outer scope during import/macro resolution"
640 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
641 AmbiguityKind::GlobVsExpanded => {
642 "glob import vs macro-expanded name in the same \
643 module during import/macro resolution"
645 AmbiguityKind::MoreExpandedVsOuter => {
646 "macro-expanded name vs less macro-expanded name \
647 from outer scope during import/macro resolution"
653 /// Miscellaneous bits of metadata for better ambiguity error reporting.
654 #[derive(Clone, Copy, PartialEq)]
655 enum AmbiguityErrorMisc {
662 struct AmbiguityError<'a> {
665 b1: &'a NameBinding<'a>,
666 b2: &'a NameBinding<'a>,
667 misc1: AmbiguityErrorMisc,
668 misc2: AmbiguityErrorMisc,
671 impl<'a> NameBinding<'a> {
672 fn module(&self) -> Option<Module<'a>> {
674 NameBindingKind::Module(module) => Some(module),
675 NameBindingKind::Import { binding, .. } => binding.module(),
680 fn res(&self) -> Res {
682 NameBindingKind::Res(res, _) => res,
683 NameBindingKind::Module(module) => module.res().unwrap(),
684 NameBindingKind::Import { binding, .. } => binding.res(),
688 fn is_ambiguity(&self) -> bool {
689 self.ambiguity.is_some()
691 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
696 // We sometimes need to treat variants as `pub` for backwards compatibility.
697 fn pseudo_vis(&self) -> ty::Visibility {
698 if self.is_variant() && self.res().def_id().is_local() {
699 ty::Visibility::Public
705 fn is_variant(&self) -> bool {
707 NameBindingKind::Res(Res::Def(DefKind::Variant, _), _)
708 | NameBindingKind::Res(Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _), _) => true,
713 fn is_extern_crate(&self) -> bool {
715 NameBindingKind::Import {
717 &ImportDirective { subclass: ImportDirectiveSubclass::ExternCrate { .. }, .. },
720 NameBindingKind::Module(&ModuleData {
721 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
723 }) => def_id.index == CRATE_DEF_INDEX,
728 fn is_import(&self) -> bool {
730 NameBindingKind::Import { .. } => true,
735 fn is_glob_import(&self) -> bool {
737 NameBindingKind::Import { directive, .. } => directive.is_glob(),
742 fn is_importable(&self) -> bool {
744 Res::Def(DefKind::AssocConst, _)
745 | Res::Def(DefKind::Method, _)
746 | Res::Def(DefKind::AssocTy, _) => false,
751 fn is_macro_def(&self) -> bool {
753 NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _) => true,
758 fn macro_kind(&self) -> Option<MacroKind> {
759 self.res().macro_kind()
762 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
763 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
764 // Then this function returns `true` if `self` may emerge from a macro *after* that
765 // in some later round and screw up our previously found resolution.
766 // See more detailed explanation in
767 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
768 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
769 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
770 // Expansions are partially ordered, so "may appear after" is an inversion of
771 // "certainly appears before or simultaneously" and includes unordered cases.
772 let self_parent_expansion = self.expansion;
773 let other_parent_expansion = binding.expansion;
774 let certainly_before_other_or_simultaneously =
775 other_parent_expansion.is_descendant_of(self_parent_expansion);
776 let certainly_before_invoc_or_simultaneously =
777 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
778 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
782 /// Interns the names of the primitive types.
784 /// All other types are defined somewhere and possibly imported, but the primitive ones need
785 /// special handling, since they have no place of origin.
786 struct PrimitiveTypeTable {
787 primitive_types: FxHashMap<Name, PrimTy>,
790 impl PrimitiveTypeTable {
791 fn new() -> PrimitiveTypeTable {
792 let mut table = FxHashMap::default();
794 table.insert(sym::bool, Bool);
795 table.insert(sym::char, Char);
796 table.insert(sym::f32, Float(FloatTy::F32));
797 table.insert(sym::f64, Float(FloatTy::F64));
798 table.insert(sym::isize, Int(IntTy::Isize));
799 table.insert(sym::i8, Int(IntTy::I8));
800 table.insert(sym::i16, Int(IntTy::I16));
801 table.insert(sym::i32, Int(IntTy::I32));
802 table.insert(sym::i64, Int(IntTy::I64));
803 table.insert(sym::i128, Int(IntTy::I128));
804 table.insert(sym::str, Str);
805 table.insert(sym::usize, Uint(UintTy::Usize));
806 table.insert(sym::u8, Uint(UintTy::U8));
807 table.insert(sym::u16, Uint(UintTy::U16));
808 table.insert(sym::u32, Uint(UintTy::U32));
809 table.insert(sym::u64, Uint(UintTy::U64));
810 table.insert(sym::u128, Uint(UintTy::U128));
811 Self { primitive_types: table }
815 #[derive(Debug, Default, Clone)]
816 pub struct ExternPreludeEntry<'a> {
817 extern_crate_item: Option<&'a NameBinding<'a>>,
818 pub introduced_by_item: bool,
821 /// The main resolver class.
823 /// This is the visitor that walks the whole crate.
824 pub struct Resolver<'a> {
825 session: &'a Session,
827 definitions: Definitions,
829 graph_root: Module<'a>,
831 prelude: Option<Module<'a>>,
832 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
834 /// N.B., this is used only for better diagnostics, not name resolution itself.
835 has_self: FxHashSet<DefId>,
837 /// Names of fields of an item `DefId` accessible with dot syntax.
838 /// Used for hints during error reporting.
839 field_names: FxHashMap<DefId, Vec<Spanned<Name>>>,
841 /// All imports known to succeed or fail.
842 determined_imports: Vec<&'a ImportDirective<'a>>,
844 /// All non-determined imports.
845 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
847 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
848 /// We are resolving a last import segment during import validation.
849 last_import_segment: bool,
850 /// This binding should be ignored during in-module resolution, so that we don't get
851 /// "self-confirming" import resolutions during import validation.
852 blacklisted_binding: Option<&'a NameBinding<'a>>,
854 /// The idents for the primitive types.
855 primitive_type_table: PrimitiveTypeTable,
857 /// Resolutions for nodes that have a single resolution.
858 partial_res_map: NodeMap<PartialRes>,
859 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
860 import_res_map: NodeMap<PerNS<Option<Res>>>,
861 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
862 label_res_map: NodeMap<NodeId>,
864 /// `CrateNum` resolutions of `extern crate` items.
865 extern_crate_map: NodeMap<CrateNum>,
866 export_map: ExportMap<NodeId>,
869 /// A map from nodes to anonymous modules.
870 /// Anonymous modules are pseudo-modules that are implicitly created around items
871 /// contained within blocks.
873 /// For example, if we have this:
881 /// There will be an anonymous module created around `g` with the ID of the
882 /// entry block for `f`.
883 block_map: NodeMap<Module<'a>>,
884 /// A fake module that contains no definition and no prelude. Used so that
885 /// some AST passes can generate identifiers that only resolve to local or
887 empty_module: Module<'a>,
888 module_map: FxHashMap<DefId, Module<'a>>,
889 extern_module_map: FxHashMap<DefId, Module<'a>>,
890 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
891 underscore_disambiguator: u32,
893 /// Maps glob imports to the names of items actually imported.
896 used_imports: FxHashSet<(NodeId, Namespace)>,
897 maybe_unused_trait_imports: NodeSet,
898 maybe_unused_extern_crates: Vec<(NodeId, Span)>,
900 /// Privacy errors are delayed until the end in order to deduplicate them.
901 privacy_errors: Vec<PrivacyError<'a>>,
902 /// Ambiguity errors are delayed for deduplication.
903 ambiguity_errors: Vec<AmbiguityError<'a>>,
904 /// `use` injections are delayed for better placement and deduplication.
905 use_injections: Vec<UseError<'a>>,
906 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
907 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
909 arenas: &'a ResolverArenas<'a>,
910 dummy_binding: &'a NameBinding<'a>,
912 crate_loader: CrateLoader<'a>,
913 macro_names: FxHashSet<Ident>,
914 builtin_macros: FxHashMap<Name, SyntaxExtension>,
915 registered_attrs: FxHashSet<Ident>,
916 registered_tools: FxHashSet<Ident>,
917 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
918 all_macros: FxHashMap<Name, Res>,
919 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
920 dummy_ext_bang: Lrc<SyntaxExtension>,
921 dummy_ext_derive: Lrc<SyntaxExtension>,
922 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
923 macro_defs: FxHashMap<ExpnId, DefId>,
924 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
925 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
926 unused_macros: NodeMap<Span>,
927 proc_macro_stubs: NodeSet,
928 /// Traces collected during macro resolution and validated when it's complete.
929 single_segment_macro_resolutions:
930 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
931 multi_segment_macro_resolutions:
932 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
933 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
934 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
935 /// Derive macros cannot modify the item themselves and have to store the markers in the global
936 /// context, so they attach the markers to derive container IDs using this resolver table.
937 containers_deriving_copy: FxHashSet<ExpnId>,
938 /// Parent scopes in which the macros were invoked.
939 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
940 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
941 /// Legacy scopes *produced* by expanding the macro invocations,
942 /// include all the `macro_rules` items and other invocations generated by them.
943 output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
944 /// Helper attributes that are in scope for the given expansion.
945 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
947 /// Avoid duplicated errors for "name already defined".
948 name_already_seen: FxHashMap<Name, Span>,
950 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
952 /// Table for mapping struct IDs into struct constructor IDs,
953 /// it's not used during normal resolution, only for better error reporting.
954 struct_constructors: DefIdMap<(Res, ty::Visibility)>,
956 /// Features enabled for this crate.
957 active_features: FxHashSet<Name>,
959 /// Stores enum visibilities to properly build a reduced graph
960 /// when visiting the correspondent variants.
961 variant_vis: DefIdMap<ty::Visibility>,
963 lint_buffer: lint::LintBuffer,
965 next_node_id: NodeId,
968 /// Nothing really interesting here; it just provides memory for the rest of the crate.
970 pub struct ResolverArenas<'a> {
971 modules: arena::TypedArena<ModuleData<'a>>,
972 local_modules: RefCell<Vec<Module<'a>>>,
973 name_bindings: arena::TypedArena<NameBinding<'a>>,
974 import_directives: arena::TypedArena<ImportDirective<'a>>,
975 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
976 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
977 ast_paths: arena::TypedArena<ast::Path>,
980 impl<'a> ResolverArenas<'a> {
981 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
982 let module = self.modules.alloc(module);
983 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
984 self.local_modules.borrow_mut().push(module);
988 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
989 self.local_modules.borrow()
991 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
992 self.name_bindings.alloc(name_binding)
994 fn alloc_import_directive(
996 import_directive: ImportDirective<'a>,
997 ) -> &'a ImportDirective<'_> {
998 self.import_directives.alloc(import_directive)
1000 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1001 self.name_resolutions.alloc(Default::default())
1003 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1004 self.legacy_bindings.alloc(binding)
1006 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1007 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1011 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1012 fn as_mut(&mut self) -> &mut Resolver<'a> {
1017 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1018 fn parent(self, id: DefId) -> Option<DefId> {
1020 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1021 _ => self.cstore().def_key(id).parent,
1023 .map(|index| DefId { index, ..id })
1027 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1028 /// the resolver is no longer needed as all the relevant information is inline.
1029 impl rustc_ast_lowering::Resolver for Resolver<'_> {
1030 fn cstore(&self) -> &dyn CrateStore {
1034 fn resolve_str_path(
1037 crate_root: Option<Name>,
1038 components: &[Name],
1040 ) -> (ast::Path, Res) {
1041 let root = if crate_root.is_some() { kw::PathRoot } else { kw::Crate };
1042 let segments = iter::once(Ident::with_dummy_span(root))
1046 .chain(components.iter().cloned())
1047 .map(Ident::with_dummy_span),
1049 .map(|i| self.new_ast_path_segment(i))
1050 .collect::<Vec<_>>();
1052 let path = ast::Path { span, segments };
1054 let parent_scope = &ParentScope::module(self.graph_root);
1055 let res = match self.resolve_ast_path(&path, ns, parent_scope) {
1057 Err((span, error)) => {
1058 self.report_error(span, error);
1065 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1066 self.partial_res_map.get(&id).cloned()
1069 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1070 self.import_res_map.get(&id).cloned().unwrap_or_default()
1073 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1074 self.label_res_map.get(&id).cloned()
1077 fn definitions(&mut self) -> &mut Definitions {
1078 &mut self.definitions
1081 fn lint_buffer(&mut self) -> &mut lint::LintBuffer {
1082 &mut self.lint_buffer
1085 fn next_node_id(&mut self) -> NodeId {
1090 impl<'a> Resolver<'a> {
1092 session: &'a Session,
1095 metadata_loader: &'a MetadataLoaderDyn,
1096 arenas: &'a ResolverArenas<'a>,
1098 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1099 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1100 let graph_root = arenas.alloc_module(ModuleData {
1101 no_implicit_prelude: attr::contains_name(&krate.attrs, sym::no_implicit_prelude),
1102 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1104 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Invalid);
1105 let empty_module = arenas.alloc_module(ModuleData {
1106 no_implicit_prelude: true,
1115 let mut module_map = FxHashMap::default();
1116 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1118 let mut definitions = Definitions::default();
1119 definitions.create_root_def(crate_name, session.local_crate_disambiguator());
1121 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1125 .filter(|(_, entry)| entry.add_prelude)
1126 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1129 if !attr::contains_name(&krate.attrs, sym::no_core) {
1130 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1131 if !attr::contains_name(&krate.attrs, sym::no_std) {
1132 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1133 if session.rust_2018() {
1134 extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
1139 let (registered_attrs, registered_tools) =
1140 macros::registered_attrs_and_tools(session, &krate.attrs);
1142 let mut invocation_parent_scopes = FxHashMap::default();
1143 invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
1145 let mut macro_defs = FxHashMap::default();
1146 macro_defs.insert(ExpnId::root(), root_def_id);
1148 let features = session.features_untracked();
1149 let non_macro_attr =
1150 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1157 // The outermost module has def ID 0; this is not reflected in the
1163 has_self: FxHashSet::default(),
1164 field_names: FxHashMap::default(),
1166 determined_imports: Vec::new(),
1167 indeterminate_imports: Vec::new(),
1169 last_import_segment: false,
1170 blacklisted_binding: None,
1172 primitive_type_table: PrimitiveTypeTable::new(),
1174 partial_res_map: Default::default(),
1175 import_res_map: Default::default(),
1176 label_res_map: Default::default(),
1177 extern_crate_map: Default::default(),
1178 export_map: FxHashMap::default(),
1179 trait_map: Default::default(),
1180 underscore_disambiguator: 0,
1183 block_map: Default::default(),
1184 extern_module_map: FxHashMap::default(),
1185 binding_parent_modules: FxHashMap::default(),
1186 ast_transform_scopes: FxHashMap::default(),
1188 glob_map: Default::default(),
1190 used_imports: FxHashSet::default(),
1191 maybe_unused_trait_imports: Default::default(),
1192 maybe_unused_extern_crates: Vec::new(),
1194 privacy_errors: Vec::new(),
1195 ambiguity_errors: Vec::new(),
1196 use_injections: Vec::new(),
1197 macro_expanded_macro_export_errors: BTreeSet::new(),
1200 dummy_binding: arenas.alloc_name_binding(NameBinding {
1201 kind: NameBindingKind::Res(Res::Err, false),
1203 expansion: ExpnId::root(),
1205 vis: ty::Visibility::Public,
1208 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1209 macro_names: FxHashSet::default(),
1210 builtin_macros: Default::default(),
1213 macro_use_prelude: FxHashMap::default(),
1214 all_macros: FxHashMap::default(),
1215 macro_map: FxHashMap::default(),
1216 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1217 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1218 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1219 invocation_parent_scopes,
1220 output_legacy_scopes: Default::default(),
1221 helper_attrs: Default::default(),
1223 local_macro_def_scopes: FxHashMap::default(),
1224 name_already_seen: FxHashMap::default(),
1225 potentially_unused_imports: Vec::new(),
1226 struct_constructors: Default::default(),
1227 unused_macros: Default::default(),
1228 proc_macro_stubs: Default::default(),
1229 single_segment_macro_resolutions: Default::default(),
1230 multi_segment_macro_resolutions: Default::default(),
1231 builtin_attrs: Default::default(),
1232 containers_deriving_copy: Default::default(),
1233 active_features: features
1234 .declared_lib_features
1236 .map(|(feat, ..)| *feat)
1237 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1239 variant_vis: Default::default(),
1240 lint_buffer: lint::LintBuffer::default(),
1241 next_node_id: NodeId::from_u32(1),
1245 pub fn next_node_id(&mut self) -> NodeId {
1250 .expect("input too large; ran out of NodeIds");
1251 self.next_node_id = ast::NodeId::from_usize(next);
1255 pub fn lint_buffer(&mut self) -> &mut lint::LintBuffer {
1256 &mut self.lint_buffer
1259 pub fn arenas() -> ResolverArenas<'a> {
1263 pub fn into_outputs(self) -> ResolverOutputs {
1265 definitions: self.definitions,
1266 cstore: Box::new(self.crate_loader.into_cstore()),
1267 extern_crate_map: self.extern_crate_map,
1268 export_map: self.export_map,
1269 trait_map: self.trait_map,
1270 glob_map: self.glob_map,
1271 maybe_unused_trait_imports: self.maybe_unused_trait_imports,
1272 maybe_unused_extern_crates: self.maybe_unused_extern_crates,
1273 extern_prelude: self
1276 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1281 pub fn clone_outputs(&self) -> ResolverOutputs {
1283 definitions: self.definitions.clone(),
1284 cstore: Box::new(self.cstore().clone()),
1285 extern_crate_map: self.extern_crate_map.clone(),
1286 export_map: self.export_map.clone(),
1287 trait_map: self.trait_map.clone(),
1288 glob_map: self.glob_map.clone(),
1289 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1290 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1291 extern_prelude: self
1294 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1299 pub fn cstore(&self) -> &CStore {
1300 self.crate_loader.cstore()
1303 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1304 self.non_macro_attrs[mark_used as usize].clone()
1307 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1309 MacroKind::Bang => self.dummy_ext_bang.clone(),
1310 MacroKind::Derive => self.dummy_ext_derive.clone(),
1311 MacroKind::Attr => self.non_macro_attr(true),
1315 /// Runs the function on each namespace.
1316 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1322 fn is_builtin_macro(&mut self, res: Res) -> bool {
1323 self.get_macro(res).map_or(false, |ext| ext.is_builtin)
1326 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1328 match self.macro_defs.get(&ctxt.outer_expn()) {
1329 Some(&def_id) => return def_id,
1330 None => ctxt.remove_mark(),
1335 /// Entry point to crate resolution.
1336 pub fn resolve_crate(&mut self, krate: &Crate) {
1337 let _prof_timer = self.session.prof.generic_activity("resolve_crate");
1339 ImportResolver { r: self }.finalize_imports();
1340 self.finalize_macro_resolutions();
1342 self.late_resolve_crate(krate);
1344 self.check_unused(krate);
1345 self.report_errors(krate);
1346 self.crate_loader.postprocess(krate);
1353 normal_ancestor_id: DefId,
1357 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expn_id, span);
1358 self.arenas.alloc_module(module)
1361 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1362 let ident = ident.modern();
1363 let disambiguator = if ident.name == kw::Underscore {
1364 self.underscore_disambiguator += 1;
1365 self.underscore_disambiguator
1369 BindingKey { ident, ns, disambiguator }
1372 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1373 if module.populate_on_access.get() {
1374 module.populate_on_access.set(false);
1375 self.build_reduced_graph_external(module);
1377 &module.lazy_resolutions
1384 ) -> &'a RefCell<NameResolution<'a>> {
1386 .resolutions(module)
1389 .or_insert_with(|| self.arenas.alloc_name_resolution())
1396 used_binding: &'a NameBinding<'a>,
1397 is_lexical_scope: bool,
1399 if let Some((b2, kind)) = used_binding.ambiguity {
1400 self.ambiguity_errors.push(AmbiguityError {
1405 misc1: AmbiguityErrorMisc::None,
1406 misc2: AmbiguityErrorMisc::None,
1409 if let NameBindingKind::Import { directive, binding, ref used } = used_binding.kind {
1410 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1411 // but not introduce it, as used if they are accessed from lexical scope.
1412 if is_lexical_scope {
1413 if let Some(entry) = self.extern_prelude.get(&ident.modern()) {
1414 if let Some(crate_item) = entry.extern_crate_item {
1415 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1422 directive.used.set(true);
1423 self.used_imports.insert((directive.id, ns));
1424 self.add_to_glob_map(&directive, ident);
1425 self.record_use(ident, ns, binding, false);
1430 fn add_to_glob_map(&mut self, directive: &ImportDirective<'_>, ident: Ident) {
1431 if directive.is_glob() {
1432 self.glob_map.entry(directive.id).or_default().insert(ident.name);
1436 /// A generic scope visitor.
1437 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1438 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1441 scope_set: ScopeSet,
1442 parent_scope: &ParentScope<'a>,
1444 mut visitor: impl FnMut(&mut Self, Scope<'a>, /*use_prelude*/ bool, Ident) -> Option<T>,
1446 // General principles:
1447 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1448 // built into the language or standard library. This way we can add new names into the
1449 // language or standard library without breaking user code.
1450 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1451 // Places to search (in order of decreasing priority):
1453 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1454 // (open set, not controlled).
1455 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1456 // (open, not controlled).
1457 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1458 // 4. Tool modules (closed, controlled right now, but not in the future).
1459 // 5. Standard library prelude (de-facto closed, controlled).
1460 // 6. Language prelude (closed, controlled).
1462 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1463 // (open set, not controlled).
1464 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1465 // (open, not controlled).
1466 // 3. Standard library prelude (de-facto closed, controlled).
1468 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1469 // are currently reported as errors. They should be higher in priority than preludes
1470 // and probably even names in modules according to the "general principles" above. They
1471 // also should be subject to restricted shadowing because are effectively produced by
1472 // derives (you need to resolve the derive first to add helpers into scope), but they
1473 // should be available before the derive is expanded for compatibility.
1474 // It's mess in general, so we are being conservative for now.
1475 // 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
1476 // priority than prelude macros, but create ambiguities with macros in modules.
1477 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1478 // (open, not controlled). Have higher priority than prelude macros, but create
1479 // ambiguities with `macro_rules`.
1480 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1481 // 4a. User-defined prelude from macro-use
1482 // (open, the open part is from macro expansions, not controlled).
1483 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1484 // 4c. Standard library prelude (de-facto closed, controlled).
1485 // 6. Language prelude: builtin attributes (closed, controlled).
1487 let rust_2015 = ident.span.rust_2015();
1488 let (ns, macro_kind, is_absolute_path) = match scope_set {
1489 ScopeSet::All(ns, _) => (ns, None, false),
1490 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1491 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1493 // Jump out of trait or enum modules, they do not act as scopes.
1494 let module = parent_scope.module.nearest_item_scope();
1495 let mut scope = match ns {
1496 _ if is_absolute_path => Scope::CrateRoot,
1497 TypeNS | ValueNS => Scope::Module(module),
1498 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1500 let mut ident = ident.modern();
1501 let mut use_prelude = !module.no_implicit_prelude;
1504 let visit = match scope {
1505 // Derive helpers are not in scope when resolving derives in the same container.
1506 Scope::DeriveHelpers(expn_id) => {
1507 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1509 Scope::DeriveHelpersCompat => true,
1510 Scope::MacroRules(..) => true,
1511 Scope::CrateRoot => true,
1512 Scope::Module(..) => true,
1513 Scope::RegisteredAttrs => use_prelude,
1514 Scope::MacroUsePrelude => use_prelude || rust_2015,
1515 Scope::BuiltinAttrs => true,
1516 Scope::ExternPrelude => use_prelude || is_absolute_path,
1517 Scope::ToolPrelude => use_prelude,
1518 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1519 Scope::BuiltinTypes => true,
1523 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ident) {
1524 return break_result;
1528 scope = match scope {
1529 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1530 // Derive helpers are not visible to code generated by bang or derive macros.
1531 let expn_data = expn_id.expn_data();
1532 match expn_data.kind {
1534 | ExpnKind::Macro(MacroKind::Bang, _)
1535 | ExpnKind::Macro(MacroKind::Derive, _) => Scope::DeriveHelpersCompat,
1536 _ => Scope::DeriveHelpers(expn_data.parent),
1539 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1540 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.legacy),
1541 Scope::MacroRules(legacy_scope) => match legacy_scope {
1542 LegacyScope::Binding(binding) => Scope::MacroRules(binding.parent_legacy_scope),
1543 LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
1544 self.output_legacy_scopes
1547 .unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy),
1549 LegacyScope::Empty => Scope::Module(module),
1551 Scope::CrateRoot => match ns {
1553 ident.span.adjust(ExpnId::root());
1554 Scope::ExternPrelude
1556 ValueNS | MacroNS => break,
1558 Scope::Module(module) => {
1559 use_prelude = !module.no_implicit_prelude;
1560 match self.hygienic_lexical_parent(module, &mut ident.span) {
1561 Some(parent_module) => Scope::Module(parent_module),
1563 ident.span.adjust(ExpnId::root());
1565 TypeNS => Scope::ExternPrelude,
1566 ValueNS => Scope::StdLibPrelude,
1567 MacroNS => Scope::RegisteredAttrs,
1572 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1573 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1574 Scope::BuiltinAttrs => break, // nowhere else to search
1575 Scope::ExternPrelude if is_absolute_path => break,
1576 Scope::ExternPrelude => Scope::ToolPrelude,
1577 Scope::ToolPrelude => Scope::StdLibPrelude,
1578 Scope::StdLibPrelude => match ns {
1579 TypeNS => Scope::BuiltinTypes,
1580 ValueNS => break, // nowhere else to search
1581 MacroNS => Scope::BuiltinAttrs,
1583 Scope::BuiltinTypes => break, // nowhere else to search
1590 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1591 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1592 /// `ident` in the first scope that defines it (or None if no scopes define it).
1594 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1595 /// the items are defined in the block. For example,
1598 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1601 /// g(); // This resolves to the local variable `g` since it shadows the item.
1605 /// Invariant: This must only be called during main resolution, not during
1606 /// import resolution.
1607 fn resolve_ident_in_lexical_scope(
1611 parent_scope: &ParentScope<'a>,
1612 record_used_id: Option<NodeId>,
1615 ) -> Option<LexicalScopeBinding<'a>> {
1616 assert!(ns == TypeNS || ns == ValueNS);
1617 if ident.name == kw::Invalid {
1618 return Some(LexicalScopeBinding::Res(Res::Err));
1620 let (general_span, modern_span) = if ident.name == kw::SelfUpper {
1621 // FIXME(jseyfried) improve `Self` hygiene
1622 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1623 (empty_span, empty_span)
1624 } else if ns == TypeNS {
1625 let modern_span = ident.span.modern();
1626 (modern_span, modern_span)
1628 (ident.span.modern_and_legacy(), ident.span.modern())
1630 ident.span = general_span;
1631 let modern_ident = Ident { span: modern_span, ..ident };
1633 // Walk backwards up the ribs in scope.
1634 let record_used = record_used_id.is_some();
1635 let mut module = self.graph_root;
1636 for i in (0..ribs.len()).rev() {
1637 debug!("walk rib\n{:?}", ribs[i].bindings);
1638 // Use the rib kind to determine whether we are resolving parameters
1639 // (modern hygiene) or local variables (legacy hygiene).
1640 let rib_ident = if ribs[i].kind.contains_params() { modern_ident } else { ident };
1641 if let Some(res) = ribs[i].bindings.get(&rib_ident).cloned() {
1642 // The ident resolves to a type parameter or local variable.
1643 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1653 module = match ribs[i].kind {
1654 ModuleRibKind(module) => module,
1655 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1656 // If an invocation of this macro created `ident`, give up on `ident`
1657 // and switch to `ident`'s source from the macro definition.
1658 ident.span.remove_mark();
1664 let item = self.resolve_ident_in_module_unadjusted(
1665 ModuleOrUniformRoot::Module(module),
1672 if let Ok(binding) = item {
1673 // The ident resolves to an item.
1674 return Some(LexicalScopeBinding::Item(binding));
1678 ModuleKind::Block(..) => {} // We can see through blocks
1683 ident = modern_ident;
1684 let mut poisoned = None;
1686 let opt_module = if let Some(node_id) = record_used_id {
1687 self.hygienic_lexical_parent_with_compatibility_fallback(
1694 self.hygienic_lexical_parent(module, &mut ident.span)
1696 module = unwrap_or!(opt_module, break);
1697 let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
1698 let result = self.resolve_ident_in_module_unadjusted(
1699 ModuleOrUniformRoot::Module(module),
1702 adjusted_parent_scope,
1709 if let Some(node_id) = poisoned {
1710 self.lint_buffer.buffer_lint_with_diagnostic(
1711 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1712 node_id, ident.span,
1713 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1714 lint::builtin::BuiltinLintDiagnostics::
1715 ProcMacroDeriveResolutionFallback(ident.span),
1718 return Some(LexicalScopeBinding::Item(binding));
1720 Err(Determined) => continue,
1721 Err(Undetermined) => {
1722 span_bug!(ident.span, "undetermined resolution during main resolution pass")
1727 if !module.no_implicit_prelude {
1728 ident.span.adjust(ExpnId::root());
1730 if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
1731 return Some(LexicalScopeBinding::Item(binding));
1733 if let Some(ident) = self.registered_tools.get(&ident) {
1735 (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
1736 .to_name_binding(self.arenas);
1737 return Some(LexicalScopeBinding::Item(binding));
1740 if let Some(prelude) = self.prelude {
1741 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1742 ModuleOrUniformRoot::Module(prelude),
1749 return Some(LexicalScopeBinding::Item(binding));
1755 if let Some(prim_ty) = self.primitive_type_table.primitive_types.get(&ident.name) {
1757 (Res::PrimTy(*prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
1758 .to_name_binding(self.arenas);
1759 return Some(LexicalScopeBinding::Item(binding));
1766 fn hygienic_lexical_parent(
1770 ) -> Option<Module<'a>> {
1771 if !module.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1772 return Some(self.macro_def_scope(span.remove_mark()));
1775 if let ModuleKind::Block(..) = module.kind {
1776 return Some(module.parent.unwrap().nearest_item_scope());
1782 fn hygienic_lexical_parent_with_compatibility_fallback(
1787 poisoned: &mut Option<NodeId>,
1788 ) -> Option<Module<'a>> {
1789 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
1793 // We need to support the next case under a deprecation warning
1796 // ---- begin: this comes from a proc macro derive
1797 // mod implementation_details {
1798 // // Note that `MyStruct` is not in scope here.
1799 // impl SomeTrait for MyStruct { ... }
1803 // So we have to fall back to the module's parent during lexical resolution in this case.
1804 if let Some(parent) = module.parent {
1805 // Inner module is inside the macro, parent module is outside of the macro.
1806 if module.expansion != parent.expansion
1807 && module.expansion.is_descendant_of(parent.expansion)
1809 // The macro is a proc macro derive
1810 if let Some(&def_id) = self.macro_defs.get(&module.expansion) {
1811 if let Some(ext) = self.get_macro_by_def_id(def_id) {
1812 if !ext.is_builtin && ext.macro_kind() == MacroKind::Derive {
1813 if parent.expansion.outer_expn_is_descendant_of(span.ctxt()) {
1814 *poisoned = Some(node_id);
1815 return module.parent;
1826 fn resolve_ident_in_module(
1828 module: ModuleOrUniformRoot<'a>,
1831 parent_scope: &ParentScope<'a>,
1834 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1835 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1836 .map_err(|(determinacy, _)| determinacy)
1839 fn resolve_ident_in_module_ext(
1841 module: ModuleOrUniformRoot<'a>,
1844 parent_scope: &ParentScope<'a>,
1847 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
1848 let tmp_parent_scope;
1849 let mut adjusted_parent_scope = parent_scope;
1851 ModuleOrUniformRoot::Module(m) => {
1852 if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
1854 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
1855 adjusted_parent_scope = &tmp_parent_scope;
1858 ModuleOrUniformRoot::ExternPrelude => {
1859 ident.span.modernize_and_adjust(ExpnId::root());
1861 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
1865 let result = self.resolve_ident_in_module_unadjusted_ext(
1869 adjusted_parent_scope,
1877 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
1878 let mut ctxt = ident.span.ctxt();
1879 let mark = if ident.name == kw::DollarCrate {
1880 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
1881 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
1882 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
1883 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
1884 // definitions actually produced by `macro` and `macro` definitions produced by
1885 // `macro_rules!`, but at least such configurations are not stable yet.
1886 ctxt = ctxt.modern_and_legacy();
1887 let mut iter = ctxt.marks().into_iter().rev().peekable();
1888 let mut result = None;
1889 // Find the last modern mark from the end if it exists.
1890 while let Some(&(mark, transparency)) = iter.peek() {
1891 if transparency == Transparency::Opaque {
1892 result = Some(mark);
1898 // Then find the last legacy mark from the end if it exists.
1899 for (mark, transparency) in iter {
1900 if transparency == Transparency::SemiTransparent {
1901 result = Some(mark);
1908 ctxt = ctxt.modern();
1909 ctxt.adjust(ExpnId::root())
1911 let module = match mark {
1912 Some(def) => self.macro_def_scope(def),
1913 None => return self.graph_root,
1915 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
1918 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
1919 let mut module = self.get_module(module.normal_ancestor_id);
1920 while module.span.ctxt().modern() != *ctxt {
1921 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
1922 module = self.get_module(parent.normal_ancestor_id);
1930 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1931 parent_scope: &ParentScope<'a>,
1934 crate_lint: CrateLint,
1935 ) -> PathResult<'a> {
1936 self.resolve_path_with_ribs(
1947 fn resolve_path_with_ribs(
1950 opt_ns: Option<Namespace>, // `None` indicates a module path in import
1951 parent_scope: &ParentScope<'a>,
1954 crate_lint: CrateLint,
1955 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
1956 ) -> PathResult<'a> {
1957 let mut module = None;
1958 let mut allow_super = true;
1959 let mut second_binding = None;
1962 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
1963 path_span={:?}, crate_lint={:?})",
1964 path, opt_ns, record_used, path_span, crate_lint,
1967 for (i, &Segment { ident, id }) in path.iter().enumerate() {
1968 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
1969 let record_segment_res = |this: &mut Self, res| {
1971 if let Some(id) = id {
1972 if !this.partial_res_map.contains_key(&id) {
1973 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
1974 this.record_partial_res(id, PartialRes::new(res));
1980 let is_last = i == path.len() - 1;
1981 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
1982 let name = ident.name;
1984 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
1987 if allow_super && name == kw::Super {
1988 let mut ctxt = ident.span.ctxt().modern();
1989 let self_module = match i {
1990 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
1992 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
1996 if let Some(self_module) = self_module {
1997 if let Some(parent) = self_module.parent {
1998 module = Some(ModuleOrUniformRoot::Module(
1999 self.resolve_self(&mut ctxt, parent),
2004 let msg = "there are too many initial `super`s.".to_string();
2005 return PathResult::Failed {
2009 is_error_from_last_segment: false,
2013 if name == kw::SelfLower {
2014 let mut ctxt = ident.span.ctxt().modern();
2015 module = Some(ModuleOrUniformRoot::Module(
2016 self.resolve_self(&mut ctxt, parent_scope.module),
2020 if name == kw::PathRoot && ident.span.rust_2018() {
2021 module = Some(ModuleOrUniformRoot::ExternPrelude);
2024 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2025 // `::a::b` from 2015 macro on 2018 global edition
2026 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2029 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2030 // `::a::b`, `crate::a::b` or `$crate::a::b`
2031 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2037 // Report special messages for path segment keywords in wrong positions.
2038 if ident.is_path_segment_keyword() && i != 0 {
2039 let name_str = if name == kw::PathRoot {
2040 "crate root".to_string()
2042 format!("`{}`", name)
2044 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2045 format!("global paths cannot start with {}", name_str)
2047 format!("{} in paths can only be used in start position", name_str)
2049 return PathResult::Failed {
2053 is_error_from_last_segment: false,
2057 let binding = if let Some(module) = module {
2058 self.resolve_ident_in_module(
2066 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2067 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2068 self.early_resolve_ident_in_lexical_scope(
2077 let record_used_id =
2078 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
2079 match self.resolve_ident_in_lexical_scope(
2087 // we found a locally-imported or available item/module
2088 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2089 // we found a local variable or type param
2090 Some(LexicalScopeBinding::Res(res))
2091 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2093 record_segment_res(self, res);
2094 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2099 _ => Err(Determinacy::determined(record_used)),
2106 second_binding = Some(binding);
2108 let res = binding.res();
2109 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2110 if let Some(next_module) = binding.module() {
2111 module = Some(ModuleOrUniformRoot::Module(next_module));
2112 record_segment_res(self, res);
2113 } else if res == Res::ToolMod && i + 1 != path.len() {
2114 if binding.is_import() {
2118 "cannot use a tool module through an import",
2120 .span_note(binding.span, "the tool module imported here")
2123 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2124 return PathResult::NonModule(PartialRes::new(res));
2125 } else if res == Res::Err {
2126 return PathResult::NonModule(PartialRes::new(Res::Err));
2127 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2128 self.lint_if_path_starts_with_module(
2134 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2139 let label = format!(
2140 "`{}` is {} {}, not a module",
2146 return PathResult::Failed {
2150 is_error_from_last_segment: is_last,
2154 Err(Undetermined) => return PathResult::Indeterminate,
2155 Err(Determined) => {
2156 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2157 if opt_ns.is_some() && !module.is_normal() {
2158 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2159 module.res().unwrap(),
2164 let module_res = match module {
2165 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2168 let (label, suggestion) = if module_res == self.graph_root.res() {
2169 let is_mod = |res| match res {
2170 Res::Def(DefKind::Mod, _) => true,
2173 let mut candidates = self.lookup_import_candidates(ident, TypeNS, is_mod);
2174 candidates.sort_by_cached_key(|c| {
2175 (c.path.segments.len(), pprust::path_to_string(&c.path))
2177 if let Some(candidate) = candidates.get(0) {
2179 String::from("unresolved import"),
2181 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2182 String::from("a similar path exists"),
2183 Applicability::MaybeIncorrect,
2186 } else if !ident.is_reserved() {
2187 (format!("maybe a missing crate `{}`?", ident), None)
2189 // the parser will already have complained about the keyword being used
2190 return PathResult::NonModule(PartialRes::new(Res::Err));
2193 (format!("use of undeclared type or module `{}`", ident), None)
2195 (format!("could not find `{}` in `{}`", ident, path[i - 1].ident), None)
2197 return PathResult::Failed {
2201 is_error_from_last_segment: is_last,
2207 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2209 PathResult::Module(match module {
2210 Some(module) => module,
2211 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2212 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2216 fn lint_if_path_starts_with_module(
2218 crate_lint: CrateLint,
2221 second_binding: Option<&NameBinding<'_>>,
2223 let (diag_id, diag_span) = match crate_lint {
2224 CrateLint::No => return,
2225 CrateLint::SimplePath(id) => (id, path_span),
2226 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2227 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2230 let first_name = match path.get(0) {
2231 // In the 2018 edition this lint is a hard error, so nothing to do
2232 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2236 // We're only interested in `use` paths which should start with
2237 // `{{root}}` currently.
2238 if first_name != kw::PathRoot {
2243 // If this import looks like `crate::...` it's already good
2244 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2245 // Otherwise go below to see if it's an extern crate
2247 // If the path has length one (and it's `PathRoot` most likely)
2248 // then we don't know whether we're gonna be importing a crate or an
2249 // item in our crate. Defer this lint to elsewhere
2253 // If the first element of our path was actually resolved to an
2254 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2255 // warning, this looks all good!
2256 if let Some(binding) = second_binding {
2257 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
2258 // Careful: we still want to rewrite paths from
2259 // renamed extern crates.
2260 if let ImportDirectiveSubclass::ExternCrate { source: None, .. } = d.subclass {
2266 let diag = lint::builtin::BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2267 self.lint_buffer.buffer_lint_with_diagnostic(
2268 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2271 "absolute paths must start with `self`, `super`, \
2272 `crate`, or an external crate name in the 2018 edition",
2277 // Validate a local resolution (from ribs).
2278 fn validate_res_from_ribs(
2285 all_ribs: &[Rib<'a>],
2287 debug!("validate_res_from_ribs({:?})", res);
2288 let ribs = &all_ribs[rib_index + 1..];
2290 // An invalid forward use of a type parameter from a previous default.
2291 if let ForwardTyParamBanRibKind = all_ribs[rib_index].kind {
2293 let res_error = if rib_ident.name == kw::SelfUpper {
2294 ResolutionError::SelfInTyParamDefault
2296 ResolutionError::ForwardDeclaredTyParam
2298 self.report_error(span, res_error);
2300 assert_eq!(res, Res::Err);
2306 use ResolutionError::*;
2307 let mut res_err = None;
2313 | MacroDefinition(..)
2314 | ForwardTyParamBanRibKind => {
2315 // Nothing to do. Continue.
2317 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2318 // This was an attempt to access an upvar inside a
2319 // named function item. This is not allowed, so we
2322 // We don't immediately trigger a resolve error, because
2323 // we want certain other resolution errors (namely those
2324 // emitted for `ConstantItemRibKind` below) to take
2326 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2329 ConstantItemRibKind => {
2330 // Still doesn't deal with upvars
2332 self.report_error(span, AttemptToUseNonConstantValueInConstant);
2338 if let Some(res_err) = res_err {
2339 self.report_error(span, res_err);
2343 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2345 let has_generic_params = match rib.kind {
2349 | MacroDefinition(..)
2350 | ForwardTyParamBanRibKind
2351 | ConstantItemRibKind => {
2352 // Nothing to do. Continue.
2355 // This was an attempt to use a type parameter outside its scope.
2356 ItemRibKind(has_generic_params) => has_generic_params,
2357 FnItemRibKind => HasGenericParams::Yes,
2363 ResolutionError::GenericParamsFromOuterFunction(
2372 Res::Def(DefKind::ConstParam, _) => {
2373 let mut ribs = ribs.iter().peekable();
2374 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2375 // When declaring const parameters inside function signatures, the first rib
2376 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2377 // (spuriously) conflicting with the const param.
2381 let has_generic_params = match rib.kind {
2382 ItemRibKind(has_generic_params) => has_generic_params,
2383 FnItemRibKind => HasGenericParams::Yes,
2387 // This was an attempt to use a const parameter outside its scope.
2391 ResolutionError::GenericParamsFromOuterFunction(
2405 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2406 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2407 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2408 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2412 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2413 vis.is_accessible_from(module.normal_ancestor_id, self)
2416 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2417 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2418 if !ptr::eq(module, old_module) {
2419 span_bug!(binding.span, "parent module is reset for binding");
2424 fn disambiguate_legacy_vs_modern(
2426 legacy: &'a NameBinding<'a>,
2427 modern: &'a NameBinding<'a>,
2429 // Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
2430 // is disambiguated to mitigate regressions from macro modularization.
2431 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2433 self.binding_parent_modules.get(&PtrKey(legacy)),
2434 self.binding_parent_modules.get(&PtrKey(modern)),
2436 (Some(legacy), Some(modern)) => {
2437 legacy.normal_ancestor_id == modern.normal_ancestor_id
2438 && modern.is_ancestor_of(legacy)
2444 fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
2446 if b.span.is_dummy() {
2447 let add_built_in = match b.res() {
2448 // These already contain the "built-in" prefix or look bad with it.
2449 Res::NonMacroAttr(..) | Res::PrimTy(..) | Res::ToolMod => false,
2452 let (built_in, from) = if from_prelude {
2453 ("", " from prelude")
2454 } else if b.is_extern_crate()
2456 && self.session.opts.externs.get(&ident.as_str()).is_some()
2458 ("", " passed with `--extern`")
2459 } else if add_built_in {
2465 let article = if built_in.is_empty() { res.article() } else { "a" };
2467 "{a}{built_in} {thing}{from}",
2469 thing = res.descr(),
2470 built_in = built_in,
2474 let introduced = if b.is_import() { "imported" } else { "defined" };
2475 format!("the {thing} {introduced} here", thing = res.descr(), introduced = introduced)
2479 fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
2480 let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
2481 let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
2482 // We have to print the span-less alternative first, otherwise formatting looks bad.
2483 (b2, b1, misc2, misc1, true)
2485 (b1, b2, misc1, misc2, false)
2488 let mut err = struct_span_err!(
2492 "`{ident}` is ambiguous ({why})",
2496 err.span_label(ident.span, "ambiguous name");
2498 let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
2499 let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
2500 let note_msg = format!(
2501 "`{ident}` could{also} refer to {what}",
2507 let thing = b.res().descr();
2508 let mut help_msgs = Vec::new();
2509 if b.is_glob_import()
2510 && (kind == AmbiguityKind::GlobVsGlob
2511 || kind == AmbiguityKind::GlobVsExpanded
2512 || kind == AmbiguityKind::GlobVsOuter && swapped != also.is_empty())
2514 help_msgs.push(format!(
2515 "consider adding an explicit import of \
2516 `{ident}` to disambiguate",
2520 if b.is_extern_crate() && ident.span.rust_2018() {
2521 help_msgs.push(format!(
2522 "use `::{ident}` to refer to this {thing} unambiguously",
2527 if misc == AmbiguityErrorMisc::SuggestCrate {
2528 help_msgs.push(format!(
2529 "use `crate::{ident}` to refer to this {thing} unambiguously",
2533 } else if misc == AmbiguityErrorMisc::SuggestSelf {
2534 help_msgs.push(format!(
2535 "use `self::{ident}` to refer to this {thing} unambiguously",
2541 err.span_note(b.span, ¬e_msg);
2542 for (i, help_msg) in help_msgs.iter().enumerate() {
2543 let or = if i == 0 { "" } else { "or " };
2544 err.help(&format!("{}{}", or, help_msg));
2548 could_refer_to(b1, misc1, "");
2549 could_refer_to(b2, misc2, " also");
2553 fn report_errors(&mut self, krate: &Crate) {
2554 self.report_with_use_injections(krate);
2556 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2557 let msg = "macro-expanded `macro_export` macros from the current crate \
2558 cannot be referred to by absolute paths";
2559 self.lint_buffer.buffer_lint_with_diagnostic(
2560 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2561 CRATE_NODE_ID, span_use, msg,
2562 lint::builtin::BuiltinLintDiagnostics::
2563 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2567 for ambiguity_error in &self.ambiguity_errors {
2568 self.report_ambiguity_error(ambiguity_error);
2571 let mut reported_spans = FxHashSet::default();
2572 for &PrivacyError(dedup_span, ident, binding) in &self.privacy_errors {
2573 if reported_spans.insert(dedup_span) {
2574 let session = &self.session;
2575 let mk_struct_span_error = |is_constructor| {
2580 "{}{} `{}` is private",
2581 binding.res().descr(),
2582 if is_constructor { " constructor" } else { "" },
2587 let mut err = if let NameBindingKind::Res(
2588 Res::Def(DefKind::Ctor(CtorOf::Struct, CtorKind::Fn), ctor_def_id),
2592 let def_id = (&*self).parent(ctor_def_id).expect("no parent for a constructor");
2593 if let Some(fields) = self.field_names.get(&def_id) {
2594 let mut err = mk_struct_span_error(true);
2595 let first_field = fields.first().expect("empty field list in the map");
2597 fields.iter().fold(first_field.span, |acc, field| acc.to(field.span)),
2598 "a constructor is private if any of the fields is private",
2602 mk_struct_span_error(false)
2605 mk_struct_span_error(false)
2613 fn report_with_use_injections(&mut self, krate: &Crate) {
2614 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
2615 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
2616 if !candidates.is_empty() {
2617 diagnostics::show_candidates(&mut err, span, &candidates, better, found_use);
2623 fn report_conflict<'b>(
2628 new_binding: &NameBinding<'b>,
2629 old_binding: &NameBinding<'b>,
2631 // Error on the second of two conflicting names
2632 if old_binding.span.lo() > new_binding.span.lo() {
2633 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2636 let container = match parent.kind {
2637 ModuleKind::Def(DefKind::Mod, _, _) => "module",
2638 ModuleKind::Def(DefKind::Trait, _, _) => "trait",
2639 ModuleKind::Block(..) => "block",
2643 let old_noun = match old_binding.is_import() {
2645 false => "definition",
2648 let new_participle = match new_binding.is_import() {
2653 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
2655 if let Some(s) = self.name_already_seen.get(&name) {
2661 let old_kind = match (ns, old_binding.module()) {
2662 (ValueNS, _) => "value",
2663 (MacroNS, _) => "macro",
2664 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2665 (TypeNS, Some(module)) if module.is_normal() => "module",
2666 (TypeNS, Some(module)) if module.is_trait() => "trait",
2667 (TypeNS, _) => "type",
2670 let msg = format!("the name `{}` is defined multiple times", name);
2672 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2673 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2674 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2675 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2676 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2678 _ => match (old_binding.is_import(), new_binding.is_import()) {
2679 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2680 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2681 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2686 "`{}` must be defined only once in the {} namespace of this {}",
2692 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2694 self.session.source_map().def_span(old_binding.span),
2695 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2698 // See https://github.com/rust-lang/rust/issues/32354
2699 use NameBindingKind::Import;
2700 let directive = match (&new_binding.kind, &old_binding.kind) {
2701 // If there are two imports where one or both have attributes then prefer removing the
2702 // import without attributes.
2703 (Import { directive: new, .. }, Import { directive: old, .. })
2705 !new_binding.span.is_dummy()
2706 && !old_binding.span.is_dummy()
2707 && (new.has_attributes || old.has_attributes)
2710 if old.has_attributes {
2711 Some((new, new_binding.span, true))
2713 Some((old, old_binding.span, true))
2716 // Otherwise prioritize the new binding.
2717 (Import { directive, .. }, other) if !new_binding.span.is_dummy() => {
2718 Some((directive, new_binding.span, other.is_import()))
2720 (other, Import { directive, .. }) if !old_binding.span.is_dummy() => {
2721 Some((directive, old_binding.span, other.is_import()))
2726 // Check if the target of the use for both bindings is the same.
2727 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2728 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2730 self.extern_prelude.get(&ident).map(|entry| entry.introduced_by_item).unwrap_or(true);
2731 // Only suggest removing an import if both bindings are to the same def, if both spans
2732 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2733 // been introduced by a item.
2734 let should_remove_import = duplicate
2736 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
2739 Some((directive, span, true)) if should_remove_import && directive.is_nested() => {
2740 self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span)
2742 Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
2743 // Simple case - remove the entire import. Due to the above match arm, this can
2744 // only be a single use so just remove it entirely.
2745 err.tool_only_span_suggestion(
2746 directive.use_span_with_attributes,
2747 "remove unnecessary import",
2749 Applicability::MaybeIncorrect,
2752 Some((directive, span, _)) => {
2753 self.add_suggestion_for_rename_of_use(&mut err, name, directive, span)
2759 self.name_already_seen.insert(name, span);
2762 /// This function adds a suggestion to change the binding name of a new import that conflicts
2763 /// with an existing import.
2765 /// ```ignore (diagnostic)
2766 /// help: you can use `as` to change the binding name of the import
2768 /// LL | use foo::bar as other_bar;
2769 /// | ^^^^^^^^^^^^^^^^^^^^^
2771 fn add_suggestion_for_rename_of_use(
2773 err: &mut DiagnosticBuilder<'_>,
2775 directive: &ImportDirective<'_>,
2778 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
2779 format!("Other{}", name)
2781 format!("other_{}", name)
2784 let mut suggestion = None;
2785 match directive.subclass {
2786 ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } => {
2787 suggestion = Some(format!("self as {}", suggested_name))
2789 ImportDirectiveSubclass::SingleImport { source, .. } => {
2791 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
2793 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
2794 if pos <= snippet.len() {
2795 suggestion = Some(format!(
2799 if snippet.ends_with(";") { ";" } else { "" }
2805 ImportDirectiveSubclass::ExternCrate { source, target, .. } => {
2806 suggestion = Some(format!(
2807 "extern crate {} as {};",
2808 source.unwrap_or(target.name),
2812 _ => unreachable!(),
2815 let rename_msg = "you can use `as` to change the binding name of the import";
2816 if let Some(suggestion) = suggestion {
2817 err.span_suggestion(
2821 Applicability::MaybeIncorrect,
2824 err.span_label(binding_span, rename_msg);
2828 /// This function adds a suggestion to remove a unnecessary binding from an import that is
2829 /// nested. In the following example, this function will be invoked to remove the `a` binding
2830 /// in the second use statement:
2832 /// ```ignore (diagnostic)
2833 /// use issue_52891::a;
2834 /// use issue_52891::{d, a, e};
2837 /// The following suggestion will be added:
2839 /// ```ignore (diagnostic)
2840 /// use issue_52891::{d, a, e};
2841 /// ^-- help: remove unnecessary import
2844 /// If the nested use contains only one import then the suggestion will remove the entire
2847 /// It is expected that the directive provided is a nested import - this isn't checked by the
2848 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
2849 /// as characters expected by span manipulations won't be present.
2850 fn add_suggestion_for_duplicate_nested_use(
2852 err: &mut DiagnosticBuilder<'_>,
2853 directive: &ImportDirective<'_>,
2856 assert!(directive.is_nested());
2857 let message = "remove unnecessary import";
2859 // Two examples will be used to illustrate the span manipulations we're doing:
2861 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
2862 // `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
2863 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
2864 // `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
2866 let (found_closing_brace, span) =
2867 find_span_of_binding_until_next_binding(self.session, binding_span, directive.use_span);
2869 // If there was a closing brace then identify the span to remove any trailing commas from
2870 // previous imports.
2871 if found_closing_brace {
2872 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
2873 err.tool_only_span_suggestion(
2877 Applicability::MaybeIncorrect,
2880 // Remove the entire line if we cannot extend the span back, this indicates a
2881 // `issue_52891::{self}` case.
2882 err.span_suggestion(
2883 directive.use_span_with_attributes,
2886 Applicability::MaybeIncorrect,
2893 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
2896 fn extern_prelude_get(
2900 ) -> Option<&'a NameBinding<'a>> {
2901 if ident.is_path_segment_keyword() {
2902 // Make sure `self`, `super` etc produce an error when passed to here.
2905 self.extern_prelude.get(&ident.modern()).cloned().and_then(|entry| {
2906 if let Some(binding) = entry.extern_crate_item {
2907 if !speculative && entry.introduced_by_item {
2908 self.record_use(ident, TypeNS, binding, false);
2912 let crate_id = if !speculative {
2913 self.crate_loader.process_path_extern(ident.name, ident.span)
2914 } else if let Some(crate_id) =
2915 self.crate_loader.maybe_process_path_extern(ident.name, ident.span)
2921 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
2923 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
2924 .to_name_binding(self.arenas),
2930 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
2931 /// isn't something that can be returned because it can't be made to live that long,
2932 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
2933 /// just that an error occurred.
2934 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
2935 pub fn resolve_str_path_error(
2941 ) -> Result<(ast::Path, Res), ()> {
2942 let path = if path_str.starts_with("::") {
2945 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
2946 .chain({ path_str.split("::").skip(1).map(Ident::from_str) })
2947 .map(|i| self.new_ast_path_segment(i))
2955 .map(Ident::from_str)
2956 .map(|i| self.new_ast_path_segment(i))
2960 let module = self.block_map.get(&module_id).copied().unwrap_or_else(|| {
2961 let def_id = self.definitions.local_def_id(module_id);
2962 self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
2964 let parent_scope = &ParentScope::module(module);
2965 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
2969 // Resolve a path passed from rustdoc or HIR lowering.
2970 fn resolve_ast_path(
2974 parent_scope: &ParentScope<'a>,
2975 ) -> Result<Res, (Span, ResolutionError<'a>)> {
2976 match self.resolve_path(
2977 &Segment::from_path(path),
2984 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
2985 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
2986 Ok(path_res.base_res())
2988 PathResult::NonModule(..) => Err((
2990 ResolutionError::FailedToResolve {
2991 label: String::from("type-relative paths are not supported in this context"),
2995 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
2996 PathResult::Failed { span, label, suggestion, .. } => {
2997 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3002 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3003 let mut seg = ast::PathSegment::from_ident(ident);
3004 seg.id = self.next_node_id();
3009 pub fn graph_root(&self) -> Module<'a> {
3014 pub fn all_macros(&self) -> &FxHashMap<Name, Res> {
3019 fn names_to_string(names: &[Name]) -> String {
3020 let mut result = String::new();
3021 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3023 result.push_str("::");
3025 if Ident::with_dummy_span(*name).is_raw_guess() {
3026 result.push_str("r#");
3028 result.push_str(&name.as_str());
3033 fn path_names_to_string(path: &Path) -> String {
3034 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3037 /// A somewhat inefficient routine to obtain the name of a module.
3038 fn module_to_string(module: Module<'_>) -> Option<String> {
3039 let mut names = Vec::new();
3041 fn collect_mod(names: &mut Vec<Name>, module: Module<'_>) {
3042 if let ModuleKind::Def(.., name) = module.kind {
3043 if let Some(parent) = module.parent {
3045 collect_mod(names, parent);
3048 names.push(Name::intern("<opaque>"));
3049 collect_mod(names, module.parent.unwrap());
3052 collect_mod(&mut names, module);
3054 if names.is_empty() {
3058 Some(names_to_string(&names))
3061 #[derive(Copy, Clone, Debug)]
3063 /// Do not issue the lint.
3066 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3067 /// In this case, we can take the span of that path.
3070 /// This lint comes from a `use` statement. In this case, what we
3071 /// care about really is the *root* `use` statement; e.g., if we
3072 /// have nested things like `use a::{b, c}`, we care about the
3074 UsePath { root_id: NodeId, root_span: Span },
3076 /// This is the "trait item" from a fully qualified path. For example,
3077 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3078 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3079 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3083 fn node_id(&self) -> Option<NodeId> {
3085 CrateLint::No => None,
3086 CrateLint::SimplePath(id)
3087 | CrateLint::UsePath { root_id: id, .. }
3088 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3093 pub fn provide(providers: &mut Providers<'_>) {
3094 lifetimes::provide(providers);