1 // ignore-tidy-filelength
3 //! This crate is responsible for the part of name resolution that doesn't require type checker.
5 //! Module structure of the crate is built here.
6 //! Paths in macros, imports, expressions, types, patterns are resolved here.
7 //! Label and lifetime names are resolved here as well.
9 //! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
11 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
12 #![feature(box_patterns)]
13 #![feature(bool_to_option)]
14 #![feature(control_flow_enum)]
15 #![feature(crate_visibility_modifier)]
16 #![feature(format_args_capture)]
19 #![cfg_attr(bootstrap, feature(or_patterns))]
20 #![recursion_limit = "256"]
21 #![allow(rustdoc::private_intra_doc_links)]
23 pub use rustc_hir::def::{Namespace, PerNS};
27 use rustc_arena::{DroplessArena, TypedArena};
28 use rustc_ast::node_id::NodeMap;
29 use rustc_ast::ptr::P;
30 use rustc_ast::visit::{self, Visitor};
31 use rustc_ast::{self as ast, NodeId};
32 use rustc_ast::{Crate, CRATE_NODE_ID};
33 use rustc_ast::{Expr, ExprKind, LitKind};
34 use rustc_ast::{ItemKind, ModKind, Path};
35 use rustc_ast_lowering::ResolverAstLowering;
36 use rustc_ast_pretty::pprust;
37 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
38 use rustc_data_structures::ptr_key::PtrKey;
39 use rustc_data_structures::sync::Lrc;
40 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
41 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
42 use rustc_hir::def::Namespace::*;
43 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
44 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
45 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
46 use rustc_hir::TraitCandidate;
47 use rustc_index::vec::IndexVec;
48 use rustc_metadata::creader::{CStore, CrateLoader};
49 use rustc_middle::hir::exports::ExportMap;
50 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
51 use rustc_middle::span_bug;
52 use rustc_middle::ty::query::Providers;
53 use rustc_middle::ty::{self, DefIdTree, ResolverOutputs};
54 use rustc_session::lint;
55 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
56 use rustc_session::Session;
57 use rustc_span::edition::Edition;
58 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
59 use rustc_span::source_map::Spanned;
60 use rustc_span::symbol::{kw, sym, Ident, Symbol};
61 use rustc_span::{Span, DUMMY_SP};
63 use smallvec::{smallvec, SmallVec};
64 use std::cell::{Cell, RefCell};
65 use std::collections::BTreeSet;
66 use std::ops::ControlFlow;
67 use std::{cmp, fmt, iter, ptr};
70 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
71 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
72 use imports::{Import, ImportKind, ImportResolver, NameResolution};
73 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
74 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
76 type Res = def::Res<NodeId>;
78 mod build_reduced_graph;
91 #[derive(Copy, Clone, PartialEq, Debug)]
92 pub enum Determinacy {
98 fn determined(determined: bool) -> Determinacy {
99 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
103 /// A specific scope in which a name can be looked up.
104 /// This enum is currently used only for early resolution (imports and macros),
105 /// but not for late resolution yet.
106 #[derive(Clone, Copy)]
108 DeriveHelpers(ExpnId),
110 MacroRules(MacroRulesScopeRef<'a>),
112 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
113 // lint if it should be reported.
114 Module(Module<'a>, Option<NodeId>),
124 /// Names from different contexts may want to visit different subsets of all specific scopes
125 /// with different restrictions when looking up the resolution.
126 /// This enum is currently used only for early resolution (imports and macros),
127 /// but not for late resolution yet.
128 #[derive(Clone, Copy)]
130 /// All scopes with the given namespace.
131 All(Namespace, /*is_import*/ bool),
132 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
133 AbsolutePath(Namespace),
134 /// All scopes with macro namespace and the given macro kind restriction.
136 /// All scopes with the given namespace, used for partially performing late resolution.
137 /// The node id enables lints and is used for reporting them.
138 Late(Namespace, Module<'a>, Option<NodeId>),
141 /// Everything you need to know about a name's location to resolve it.
142 /// Serves as a starting point for the scope visitor.
143 /// This struct is currently used only for early resolution (imports and macros),
144 /// but not for late resolution yet.
145 #[derive(Clone, Copy, Debug)]
146 pub struct ParentScope<'a> {
149 macro_rules: MacroRulesScopeRef<'a>,
150 derives: &'a [ast::Path],
153 impl<'a> ParentScope<'a> {
154 /// Creates a parent scope with the passed argument used as the module scope component,
155 /// and other scope components set to default empty values.
156 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
159 expansion: ExpnId::root(),
160 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
166 #[derive(Copy, Debug, Clone)]
167 enum ImplTraitContext {
169 Universal(LocalDefId),
173 struct BindingError {
175 origin: BTreeSet<Span>,
176 target: BTreeSet<Span>,
180 impl PartialOrd for BindingError {
181 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
182 Some(self.cmp(other))
186 impl PartialEq for BindingError {
187 fn eq(&self, other: &BindingError) -> bool {
188 self.name == other.name
192 impl Ord for BindingError {
193 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
194 self.name.cmp(&other.name)
198 enum ResolutionError<'a> {
199 /// Error E0401: can't use type or const parameters from outer function.
200 GenericParamsFromOuterFunction(Res, HasGenericParams),
201 /// Error E0403: the name is already used for a type or const parameter in this generic
203 NameAlreadyUsedInParameterList(Symbol, Span),
204 /// Error E0407: method is not a member of trait.
205 MethodNotMemberOfTrait(Symbol, &'a str),
206 /// Error E0437: type is not a member of trait.
207 TypeNotMemberOfTrait(Symbol, &'a str),
208 /// Error E0438: const is not a member of trait.
209 ConstNotMemberOfTrait(Symbol, &'a str),
210 /// Error E0408: variable `{}` is not bound in all patterns.
211 VariableNotBoundInPattern(&'a BindingError),
212 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
213 VariableBoundWithDifferentMode(Symbol, Span),
214 /// Error E0415: identifier is bound more than once in this parameter list.
215 IdentifierBoundMoreThanOnceInParameterList(Symbol),
216 /// Error E0416: identifier is bound more than once in the same pattern.
217 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
218 /// Error E0426: use of undeclared label.
219 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
220 /// Error E0429: `self` imports are only allowed within a `{ }` list.
221 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
222 /// Error E0430: `self` import can only appear once in the list.
223 SelfImportCanOnlyAppearOnceInTheList,
224 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
225 SelfImportOnlyInImportListWithNonEmptyPrefix,
226 /// Error E0433: failed to resolve.
227 FailedToResolve { label: String, suggestion: Option<Suggestion> },
228 /// Error E0434: can't capture dynamic environment in a fn item.
229 CannotCaptureDynamicEnvironmentInFnItem,
230 /// Error E0435: attempt to use a non-constant value in a constant.
231 AttemptToUseNonConstantValueInConstant(
233 /* suggestion */ &'static str,
234 /* current */ &'static str,
236 /// Error E0530: `X` bindings cannot shadow `Y`s.
237 BindingShadowsSomethingUnacceptable(&'static str, Symbol, &'a NameBinding<'a>),
238 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
239 ForwardDeclaredTyParam, // FIXME(const_generics_defaults)
240 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
241 ParamInTyOfConstParam(Symbol),
242 /// constant values inside of type parameter defaults must not depend on generic parameters.
243 ParamInAnonConstInTyDefault(Symbol),
244 /// generic parameters must not be used inside const evaluations.
246 /// This error is only emitted when using `min_const_generics`.
247 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
248 /// Error E0735: generic parameters with a default cannot use `Self`
249 SelfInTyParamDefault,
250 /// Error E0767: use of unreachable label
251 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
254 enum VisResolutionError<'a> {
255 Relative2018(Span, &'a ast::Path),
257 FailedToResolve(Span, String, Option<Suggestion>),
258 ExpectedFound(Span, String, Res),
263 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
264 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
265 #[derive(Clone, Copy, Debug)]
269 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
270 /// nonsensical suggestions.
271 has_generic_args: bool,
275 fn from_path(path: &Path) -> Vec<Segment> {
276 path.segments.iter().map(|s| s.into()).collect()
279 fn from_ident(ident: Ident) -> Segment {
280 Segment { ident, id: None, has_generic_args: false }
283 fn names_to_string(segments: &[Segment]) -> String {
284 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
288 impl<'a> From<&'a ast::PathSegment> for Segment {
289 fn from(seg: &'a ast::PathSegment) -> Segment {
290 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
294 struct UsePlacementFinder {
295 target_module: NodeId,
300 impl UsePlacementFinder {
301 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
302 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
303 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
304 visit::walk_crate(&mut finder, krate);
306 (finder.span, finder.found_use)
309 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
310 if self.span.is_some() {
311 return ControlFlow::Break(());
313 if node_id != self.target_module {
314 return ControlFlow::Continue(());
316 // find a use statement
319 ItemKind::Use(..) => {
320 // don't suggest placing a use before the prelude
321 // import or other generated ones
322 if !item.span.from_expansion() {
323 self.span = Some(item.span.shrink_to_lo());
324 self.found_use = true;
325 return ControlFlow::Break(());
328 // don't place use before extern crate
329 ItemKind::ExternCrate(_) => {}
330 // but place them before the first other item
332 if self.span.map_or(true, |span| item.span < span)
333 && !item.span.from_expansion()
335 // don't insert between attributes and an item
336 if item.attrs.is_empty() {
337 self.span = Some(item.span.shrink_to_lo());
339 // find the first attribute on the item
340 for attr in &item.attrs {
341 if self.span.map_or(true, |span| attr.span < span) {
342 self.span = Some(attr.span.shrink_to_lo());
350 ControlFlow::Continue(())
354 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
355 fn visit_item(&mut self, item: &'tcx ast::Item) {
356 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
357 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
361 visit::walk_item(self, item);
365 /// An intermediate resolution result.
367 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
368 /// items are visible in their whole block, while `Res`es only from the place they are defined
371 enum LexicalScopeBinding<'a> {
372 Item(&'a NameBinding<'a>),
376 impl<'a> LexicalScopeBinding<'a> {
377 fn res(self) -> Res {
379 LexicalScopeBinding::Item(binding) => binding.res(),
380 LexicalScopeBinding::Res(res) => res,
385 #[derive(Copy, Clone, Debug)]
386 enum ModuleOrUniformRoot<'a> {
390 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
391 CrateRootAndExternPrelude,
393 /// Virtual module that denotes resolution in extern prelude.
394 /// Used for paths starting with `::` on 2018 edition.
397 /// Virtual module that denotes resolution in current scope.
398 /// Used only for resolving single-segment imports. The reason it exists is that import paths
399 /// are always split into two parts, the first of which should be some kind of module.
403 impl ModuleOrUniformRoot<'_> {
404 fn same_def(lhs: Self, rhs: Self) -> bool {
406 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
407 lhs.def_id() == rhs.def_id()
410 ModuleOrUniformRoot::CrateRootAndExternPrelude,
411 ModuleOrUniformRoot::CrateRootAndExternPrelude,
413 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
414 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
420 #[derive(Clone, Debug)]
421 enum PathResult<'a> {
422 Module(ModuleOrUniformRoot<'a>),
423 NonModule(PartialRes),
428 suggestion: Option<Suggestion>,
429 is_error_from_last_segment: bool,
435 /// An anonymous module; e.g., just a block.
440 /// { // This is an anonymous module
441 /// f(); // This resolves to (2) as we are inside the block.
444 /// f(); // Resolves to (1)
448 /// Any module with a name.
452 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
453 /// or the crate root (which is conceptually a top-level module).
454 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
455 /// * A trait or an enum (it implicitly contains associated types, methods and variant
457 Def(DefKind, DefId, Symbol),
461 /// Get name of the module.
462 pub fn name(&self) -> Option<Symbol> {
464 ModuleKind::Block(..) => None,
465 ModuleKind::Def(.., name) => Some(*name),
470 /// A key that identifies a binding in a given `Module`.
472 /// Multiple bindings in the same module can have the same key (in a valid
473 /// program) if all but one of them come from glob imports.
474 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
476 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
480 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
481 /// `_` in the expanded AST that introduced this binding.
485 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
487 /// One node in the tree of modules.
489 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
492 /// * crate root (aka, top-level anonymous module)
495 /// * curly-braced block with statements
497 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
498 pub struct ModuleData<'a> {
499 /// The direct parent module (it may not be a `mod`, however).
500 parent: Option<Module<'a>>,
501 /// What kind of module this is, because this may not be a `mod`.
504 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
505 /// This may be the crate root.
506 nearest_parent_mod: DefId,
508 /// Mapping between names and their (possibly in-progress) resolutions in this module.
509 /// Resolutions in modules from other crates are not populated until accessed.
510 lazy_resolutions: Resolutions<'a>,
511 /// True if this is a module from other crate that needs to be populated on access.
512 populate_on_access: Cell<bool>,
514 /// Macro invocations that can expand into items in this module.
515 unexpanded_invocations: RefCell<FxHashSet<ExpnId>>,
517 /// Whether `#[no_implicit_prelude]` is active.
518 no_implicit_prelude: bool,
520 glob_importers: RefCell<Vec<&'a Import<'a>>>,
521 globs: RefCell<Vec<&'a Import<'a>>>,
523 /// Used to memoize the traits in this module for faster searches through all traits in scope.
524 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
526 /// Span of the module itself. Used for error reporting.
532 type Module<'a> = &'a ModuleData<'a>;
534 impl<'a> ModuleData<'a> {
536 parent: Option<Module<'a>>,
538 nearest_parent_mod: DefId,
546 lazy_resolutions: Default::default(),
547 populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
548 unexpanded_invocations: Default::default(),
549 no_implicit_prelude: false,
550 glob_importers: RefCell::new(Vec::new()),
551 globs: RefCell::new(Vec::new()),
552 traits: RefCell::new(None),
558 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
560 R: AsMut<Resolver<'a>>,
561 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
563 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
564 if let Some(binding) = name_resolution.borrow().binding {
565 f(resolver, key.ident, key.ns, binding);
570 /// This modifies `self` in place. The traits will be stored in `self.traits`.
571 fn ensure_traits<R>(&'a self, resolver: &mut R)
573 R: AsMut<Resolver<'a>>,
575 let mut traits = self.traits.borrow_mut();
576 if traits.is_none() {
577 let mut collected_traits = Vec::new();
578 self.for_each_child(resolver, |_, name, ns, binding| {
582 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
583 collected_traits.push((name, binding))
586 *traits = Some(collected_traits.into_boxed_slice());
590 fn res(&self) -> Option<Res> {
592 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
597 fn def_id(&self) -> Option<DefId> {
599 ModuleKind::Def(_, def_id, _) => Some(def_id),
604 // `self` resolves to the first module ancestor that `is_normal`.
605 fn is_normal(&self) -> bool {
606 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
609 fn is_trait(&self) -> bool {
610 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
613 fn nearest_item_scope(&'a self) -> Module<'a> {
615 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
616 self.parent.expect("enum or trait module without a parent")
622 fn is_ancestor_of(&self, mut other: &Self) -> bool {
623 while !ptr::eq(self, other) {
624 if let Some(parent) = other.parent {
634 impl<'a> fmt::Debug for ModuleData<'a> {
635 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
636 write!(f, "{:?}", self.res())
640 /// Records a possibly-private value, type, or module definition.
641 #[derive(Clone, Debug)]
642 pub struct NameBinding<'a> {
643 kind: NameBindingKind<'a>,
644 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
650 pub trait ToNameBinding<'a> {
651 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
654 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
655 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
660 #[derive(Clone, Debug)]
661 enum NameBindingKind<'a> {
662 Res(Res, /* is_macro_export */ bool),
664 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
667 impl<'a> NameBindingKind<'a> {
668 /// Is this a name binding of a import?
669 fn is_import(&self) -> bool {
670 matches!(*self, NameBindingKind::Import { .. })
674 struct PrivacyError<'a> {
676 binding: &'a NameBinding<'a>,
680 struct UseError<'a> {
681 err: DiagnosticBuilder<'a>,
682 /// Candidates which user could `use` to access the missing type.
683 candidates: Vec<ImportSuggestion>,
684 /// The `DefId` of the module to place the use-statements in.
686 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
688 /// Extra free-form suggestion.
689 suggestion: Option<(Span, &'static str, String, Applicability)>,
692 #[derive(Clone, Copy, PartialEq, Debug)]
697 MacroRulesVsModularized,
705 fn descr(self) -> &'static str {
707 AmbiguityKind::Import => "name vs any other name during import resolution",
708 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
709 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
710 AmbiguityKind::MacroRulesVsModularized => {
711 "`macro_rules` vs non-`macro_rules` from other module"
713 AmbiguityKind::GlobVsOuter => {
714 "glob import vs any other name from outer scope during import/macro resolution"
716 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
717 AmbiguityKind::GlobVsExpanded => {
718 "glob import vs macro-expanded name in the same \
719 module during import/macro resolution"
721 AmbiguityKind::MoreExpandedVsOuter => {
722 "macro-expanded name vs less macro-expanded name \
723 from outer scope during import/macro resolution"
729 /// Miscellaneous bits of metadata for better ambiguity error reporting.
730 #[derive(Clone, Copy, PartialEq)]
731 enum AmbiguityErrorMisc {
738 struct AmbiguityError<'a> {
741 b1: &'a NameBinding<'a>,
742 b2: &'a NameBinding<'a>,
743 misc1: AmbiguityErrorMisc,
744 misc2: AmbiguityErrorMisc,
747 impl<'a> NameBinding<'a> {
748 fn module(&self) -> Option<Module<'a>> {
750 NameBindingKind::Module(module) => Some(module),
751 NameBindingKind::Import { binding, .. } => binding.module(),
756 fn res(&self) -> Res {
758 NameBindingKind::Res(res, _) => res,
759 NameBindingKind::Module(module) => module.res().unwrap(),
760 NameBindingKind::Import { binding, .. } => binding.res(),
764 fn is_ambiguity(&self) -> bool {
765 self.ambiguity.is_some()
767 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
772 fn is_possibly_imported_variant(&self) -> bool {
774 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
775 NameBindingKind::Res(
776 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
779 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
783 fn is_extern_crate(&self) -> bool {
785 NameBindingKind::Import {
786 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
789 NameBindingKind::Module(&ModuleData {
790 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
792 }) => def_id.index == CRATE_DEF_INDEX,
797 fn is_import(&self) -> bool {
798 matches!(self.kind, NameBindingKind::Import { .. })
801 fn is_glob_import(&self) -> bool {
803 NameBindingKind::Import { import, .. } => import.is_glob(),
808 fn is_importable(&self) -> bool {
811 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
815 fn is_macro_def(&self) -> bool {
816 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
819 fn macro_kind(&self) -> Option<MacroKind> {
820 self.res().macro_kind()
823 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
824 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
825 // Then this function returns `true` if `self` may emerge from a macro *after* that
826 // in some later round and screw up our previously found resolution.
827 // See more detailed explanation in
828 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
829 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
830 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
831 // Expansions are partially ordered, so "may appear after" is an inversion of
832 // "certainly appears before or simultaneously" and includes unordered cases.
833 let self_parent_expansion = self.expansion;
834 let other_parent_expansion = binding.expansion;
835 let certainly_before_other_or_simultaneously =
836 other_parent_expansion.is_descendant_of(self_parent_expansion);
837 let certainly_before_invoc_or_simultaneously =
838 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
839 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
843 #[derive(Debug, Default, Clone)]
844 pub struct ExternPreludeEntry<'a> {
845 extern_crate_item: Option<&'a NameBinding<'a>>,
846 pub introduced_by_item: bool,
849 /// Used for better errors for E0773
850 enum BuiltinMacroState {
851 NotYetSeen(SyntaxExtensionKind),
856 resolutions: DeriveResolutions,
857 helper_attrs: Vec<(usize, Ident)>,
858 has_derive_copy: bool,
861 /// The main resolver class.
863 /// This is the visitor that walks the whole crate.
864 pub struct Resolver<'a> {
865 session: &'a Session,
867 definitions: Definitions,
869 graph_root: Module<'a>,
871 prelude: Option<Module<'a>>,
872 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
874 /// N.B., this is used only for better diagnostics, not name resolution itself.
875 has_self: FxHashSet<DefId>,
877 /// Names of fields of an item `DefId` accessible with dot syntax.
878 /// Used for hints during error reporting.
879 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
881 /// All imports known to succeed or fail.
882 determined_imports: Vec<&'a Import<'a>>,
884 /// All non-determined imports.
885 indeterminate_imports: Vec<&'a Import<'a>>,
887 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
888 /// We are resolving a last import segment during import validation.
889 last_import_segment: bool,
890 /// This binding should be ignored during in-module resolution, so that we don't get
891 /// "self-confirming" import resolutions during import validation.
892 unusable_binding: Option<&'a NameBinding<'a>>,
894 /// Resolutions for nodes that have a single resolution.
895 partial_res_map: NodeMap<PartialRes>,
896 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
897 import_res_map: NodeMap<PerNS<Option<Res>>>,
898 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
899 label_res_map: NodeMap<NodeId>,
901 /// `CrateNum` resolutions of `extern crate` items.
902 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
903 export_map: ExportMap<LocalDefId>,
904 trait_map: NodeMap<Vec<TraitCandidate>>,
906 /// A map from nodes to anonymous modules.
907 /// Anonymous modules are pseudo-modules that are implicitly created around items
908 /// contained within blocks.
910 /// For example, if we have this:
918 /// There will be an anonymous module created around `g` with the ID of the
919 /// entry block for `f`.
920 block_map: NodeMap<Module<'a>>,
921 /// A fake module that contains no definition and no prelude. Used so that
922 /// some AST passes can generate identifiers that only resolve to local or
924 empty_module: Module<'a>,
925 module_map: FxHashMap<LocalDefId, Module<'a>>,
926 extern_module_map: FxHashMap<DefId, Module<'a>>,
927 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
928 underscore_disambiguator: u32,
930 /// Maps glob imports to the names of items actually imported.
931 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
932 /// Visibilities in "lowered" form, for all entities that have them.
933 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
934 used_imports: FxHashSet<(NodeId, Namespace)>,
935 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
936 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
938 /// Privacy errors are delayed until the end in order to deduplicate them.
939 privacy_errors: Vec<PrivacyError<'a>>,
940 /// Ambiguity errors are delayed for deduplication.
941 ambiguity_errors: Vec<AmbiguityError<'a>>,
942 /// `use` injections are delayed for better placement and deduplication.
943 use_injections: Vec<UseError<'a>>,
944 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
945 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
947 arenas: &'a ResolverArenas<'a>,
948 dummy_binding: &'a NameBinding<'a>,
950 crate_loader: CrateLoader<'a>,
951 macro_names: FxHashSet<Ident>,
952 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
953 registered_attrs: FxHashSet<Ident>,
954 registered_tools: FxHashSet<Ident>,
955 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
956 all_macros: FxHashMap<Symbol, Res>,
957 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
958 dummy_ext_bang: Lrc<SyntaxExtension>,
959 dummy_ext_derive: Lrc<SyntaxExtension>,
960 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
961 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
962 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
963 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
964 proc_macro_stubs: FxHashSet<LocalDefId>,
965 /// Traces collected during macro resolution and validated when it's complete.
966 single_segment_macro_resolutions:
967 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
968 multi_segment_macro_resolutions:
969 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
970 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
971 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
972 /// Derive macros cannot modify the item themselves and have to store the markers in the global
973 /// context, so they attach the markers to derive container IDs using this resolver table.
974 containers_deriving_copy: FxHashSet<ExpnId>,
975 /// Parent scopes in which the macros were invoked.
976 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
977 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
978 /// `macro_rules` scopes *produced* by expanding the macro invocations,
979 /// include all the `macro_rules` items and other invocations generated by them.
980 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScopeRef<'a>>,
981 /// Helper attributes that are in scope for the given expansion.
982 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
983 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
984 /// with the given `ExpnId`.
985 derive_data: FxHashMap<ExpnId, DeriveData>,
987 /// Avoid duplicated errors for "name already defined".
988 name_already_seen: FxHashMap<Symbol, Span>,
990 potentially_unused_imports: Vec<&'a Import<'a>>,
992 /// Table for mapping struct IDs into struct constructor IDs,
993 /// it's not used during normal resolution, only for better error reporting.
994 /// Also includes of list of each fields visibility
995 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
997 /// Features enabled for this crate.
998 active_features: FxHashSet<Symbol>,
1000 lint_buffer: LintBuffer,
1002 next_node_id: NodeId,
1004 def_id_to_span: IndexVec<LocalDefId, Span>,
1006 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1007 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1009 /// Indices of unnamed struct or variant fields with unresolved attributes.
1010 placeholder_field_indices: FxHashMap<NodeId, usize>,
1011 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1012 /// we know what parent node that fragment should be attached to thanks to this table,
1013 /// and how the `impl Trait` fragments were introduced.
1014 invocation_parents: FxHashMap<ExpnId, (LocalDefId, ImplTraitContext)>,
1016 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1017 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1018 /// FIXME: Replace with a more general AST map (together with some other fields).
1019 trait_impl_items: FxHashSet<LocalDefId>,
1021 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1024 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1026 pub struct ResolverArenas<'a> {
1027 modules: TypedArena<ModuleData<'a>>,
1028 local_modules: RefCell<Vec<Module<'a>>>,
1029 imports: TypedArena<Import<'a>>,
1030 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1031 ast_paths: TypedArena<ast::Path>,
1032 dropless: DroplessArena,
1035 impl<'a> ResolverArenas<'a> {
1036 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1037 let module = self.modules.alloc(module);
1038 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1039 self.local_modules.borrow_mut().push(module);
1043 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1044 self.local_modules.borrow()
1046 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1047 self.dropless.alloc(name_binding)
1049 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1050 self.imports.alloc(import)
1052 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1053 self.name_resolutions.alloc(Default::default())
1055 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1056 PtrKey(self.dropless.alloc(Cell::new(scope)))
1058 fn alloc_macro_rules_binding(
1060 binding: MacroRulesBinding<'a>,
1061 ) -> &'a MacroRulesBinding<'a> {
1062 self.dropless.alloc(binding)
1064 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1065 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1067 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1068 self.dropless.alloc_from_iter(spans)
1072 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1073 fn as_mut(&mut self) -> &mut Resolver<'a> {
1078 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1079 fn parent(self, id: DefId) -> Option<DefId> {
1080 match id.as_local() {
1081 Some(id) => self.definitions.def_key(id).parent,
1082 None => self.cstore().def_key(id).parent,
1084 .map(|index| DefId { index, ..id })
1088 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1089 /// the resolver is no longer needed as all the relevant information is inline.
1090 impl ResolverAstLowering for Resolver<'_> {
1091 fn def_key(&mut self, id: DefId) -> DefKey {
1092 if let Some(id) = id.as_local() {
1093 self.definitions().def_key(id)
1095 self.cstore().def_key(id)
1099 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1100 self.cstore().item_generics_num_lifetimes(def_id, sess)
1103 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1104 self.legacy_const_generic_args(expr)
1107 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1108 self.partial_res_map.get(&id).cloned()
1111 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1112 self.import_res_map.get(&id).cloned().unwrap_or_default()
1115 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1116 self.label_res_map.get(&id).cloned()
1119 fn definitions(&mut self) -> &mut Definitions {
1120 &mut self.definitions
1123 fn lint_buffer(&mut self) -> &mut LintBuffer {
1124 &mut self.lint_buffer
1127 fn next_node_id(&mut self) -> NodeId {
1131 fn trait_map(&self) -> &NodeMap<Vec<TraitCandidate>> {
1135 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1136 self.node_id_to_def_id.get(&node).copied()
1139 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1140 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1143 /// Adds a definition with a parent definition.
1147 node_id: ast::NodeId,
1153 !self.node_id_to_def_id.contains_key(&node_id),
1154 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1157 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1160 // Find the next free disambiguator for this key.
1161 let next_disambiguator = &mut self.next_disambiguator;
1162 let next_disambiguator = |parent, data| {
1163 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1164 let disambiguator = *next_disamb;
1165 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1169 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1171 assert_eq!(self.def_id_to_span.push(span), def_id);
1173 // Some things for which we allocate `LocalDefId`s don't correspond to
1174 // anything in the AST, so they don't have a `NodeId`. For these cases
1175 // we don't need a mapping from `NodeId` to `LocalDefId`.
1176 if node_id != ast::DUMMY_NODE_ID {
1177 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1178 self.node_id_to_def_id.insert(node_id, def_id);
1180 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1186 impl<'a> Resolver<'a> {
1188 session: &'a Session,
1191 metadata_loader: &'a MetadataLoaderDyn,
1192 arenas: &'a ResolverArenas<'a>,
1194 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1195 let root_def_id = root_local_def_id.to_def_id();
1196 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1197 let graph_root = arenas.alloc_module(ModuleData {
1198 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1199 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1201 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1202 let empty_module = arenas.alloc_module(ModuleData {
1203 no_implicit_prelude: true,
1212 let mut module_map = FxHashMap::default();
1213 module_map.insert(root_local_def_id, graph_root);
1215 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1216 let root = definitions.get_root_def();
1218 let mut visibilities = FxHashMap::default();
1219 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1221 let mut def_id_to_span = IndexVec::default();
1222 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1223 let mut def_id_to_node_id = IndexVec::default();
1224 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1225 let mut node_id_to_def_id = FxHashMap::default();
1226 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1228 let mut invocation_parents = FxHashMap::default();
1229 invocation_parents.insert(ExpnId::root(), (root, ImplTraitContext::Existential));
1231 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1235 .filter(|(_, entry)| entry.add_prelude)
1236 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1239 if !session.contains_name(&krate.attrs, sym::no_core) {
1240 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1241 if !session.contains_name(&krate.attrs, sym::no_std) {
1242 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1246 let (registered_attrs, registered_tools) =
1247 macros::registered_attrs_and_tools(session, &krate.attrs);
1249 let features = session.features_untracked();
1250 let non_macro_attr =
1251 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1253 let mut resolver = Resolver {
1258 // The outermost module has def ID 0; this is not reflected in the
1264 has_self: FxHashSet::default(),
1265 field_names: FxHashMap::default(),
1267 determined_imports: Vec::new(),
1268 indeterminate_imports: Vec::new(),
1270 last_import_segment: false,
1271 unusable_binding: None,
1273 partial_res_map: Default::default(),
1274 import_res_map: Default::default(),
1275 label_res_map: Default::default(),
1276 extern_crate_map: Default::default(),
1277 export_map: FxHashMap::default(),
1278 trait_map: Default::default(),
1279 underscore_disambiguator: 0,
1282 block_map: Default::default(),
1283 extern_module_map: FxHashMap::default(),
1284 binding_parent_modules: FxHashMap::default(),
1285 ast_transform_scopes: FxHashMap::default(),
1287 glob_map: Default::default(),
1289 used_imports: FxHashSet::default(),
1290 maybe_unused_trait_imports: Default::default(),
1291 maybe_unused_extern_crates: Vec::new(),
1293 privacy_errors: Vec::new(),
1294 ambiguity_errors: Vec::new(),
1295 use_injections: Vec::new(),
1296 macro_expanded_macro_export_errors: BTreeSet::new(),
1299 dummy_binding: arenas.alloc_name_binding(NameBinding {
1300 kind: NameBindingKind::Res(Res::Err, false),
1302 expansion: ExpnId::root(),
1304 vis: ty::Visibility::Public,
1307 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1308 macro_names: FxHashSet::default(),
1309 builtin_macros: Default::default(),
1312 macro_use_prelude: FxHashMap::default(),
1313 all_macros: FxHashMap::default(),
1314 macro_map: FxHashMap::default(),
1315 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1316 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1317 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1318 invocation_parent_scopes: Default::default(),
1319 output_macro_rules_scopes: Default::default(),
1320 helper_attrs: Default::default(),
1321 derive_data: Default::default(),
1322 local_macro_def_scopes: FxHashMap::default(),
1323 name_already_seen: FxHashMap::default(),
1324 potentially_unused_imports: Vec::new(),
1325 struct_constructors: Default::default(),
1326 unused_macros: Default::default(),
1327 proc_macro_stubs: Default::default(),
1328 single_segment_macro_resolutions: Default::default(),
1329 multi_segment_macro_resolutions: Default::default(),
1330 builtin_attrs: Default::default(),
1331 containers_deriving_copy: Default::default(),
1332 active_features: features
1333 .declared_lib_features
1335 .map(|(feat, ..)| *feat)
1336 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1338 lint_buffer: LintBuffer::default(),
1339 next_node_id: NodeId::from_u32(1),
1343 placeholder_field_indices: Default::default(),
1345 next_disambiguator: Default::default(),
1346 trait_impl_items: Default::default(),
1347 legacy_const_generic_args: Default::default(),
1350 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1351 resolver.invocation_parent_scopes.insert(ExpnId::root(), root_parent_scope);
1356 pub fn next_node_id(&mut self) -> NodeId {
1361 .expect("input too large; ran out of NodeIds");
1362 self.next_node_id = ast::NodeId::from_usize(next);
1366 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1367 &mut self.lint_buffer
1370 pub fn arenas() -> ResolverArenas<'a> {
1374 pub fn into_outputs(self) -> ResolverOutputs {
1375 let definitions = self.definitions;
1376 let visibilities = self.visibilities;
1377 let extern_crate_map = self.extern_crate_map;
1378 let export_map = self.export_map;
1379 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1380 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1381 let glob_map = self.glob_map;
1384 cstore: Box::new(self.crate_loader.into_cstore()),
1389 maybe_unused_trait_imports,
1390 maybe_unused_extern_crates,
1391 extern_prelude: self
1394 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1399 pub fn clone_outputs(&self) -> ResolverOutputs {
1401 definitions: self.definitions.clone(),
1402 cstore: Box::new(self.cstore().clone()),
1403 visibilities: self.visibilities.clone(),
1404 extern_crate_map: self.extern_crate_map.clone(),
1405 export_map: self.export_map.clone(),
1406 glob_map: self.glob_map.clone(),
1407 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1408 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1409 extern_prelude: self
1412 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1417 pub fn cstore(&self) -> &CStore {
1418 self.crate_loader.cstore()
1421 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1422 self.non_macro_attrs[mark_used as usize].clone()
1425 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1427 MacroKind::Bang => self.dummy_ext_bang.clone(),
1428 MacroKind::Derive => self.dummy_ext_derive.clone(),
1429 MacroKind::Attr => self.non_macro_attr(true),
1433 /// Runs the function on each namespace.
1434 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1440 fn is_builtin_macro(&mut self, res: Res) -> bool {
1441 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1444 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1446 match ctxt.outer_expn_data().macro_def_id {
1447 Some(def_id) => return def_id,
1448 None => ctxt.remove_mark(),
1453 /// Entry point to crate resolution.
1454 pub fn resolve_crate(&mut self, krate: &Crate) {
1455 self.session.time("resolve_crate", || {
1456 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1457 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1458 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1459 self.session.time("resolve_check_unused", || self.check_unused(krate));
1460 self.session.time("resolve_report_errors", || self.report_errors(krate));
1461 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1465 pub fn traits_in_scope(
1467 current_trait: Option<Module<'a>>,
1468 parent_scope: &ParentScope<'a>,
1469 ctxt: SyntaxContext,
1470 assoc_item: Option<(Symbol, Namespace)>,
1471 ) -> Vec<TraitCandidate> {
1472 let mut found_traits = Vec::new();
1474 if let Some(module) = current_trait {
1475 if self.trait_may_have_item(Some(module), assoc_item) {
1476 let def_id = module.def_id().unwrap();
1477 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1481 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1483 Scope::Module(module, _) => {
1484 this.traits_in_module(module, assoc_item, &mut found_traits);
1486 Scope::StdLibPrelude => {
1487 if let Some(module) = this.prelude {
1488 this.traits_in_module(module, assoc_item, &mut found_traits);
1491 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1492 _ => unreachable!(),
1500 fn traits_in_module(
1503 assoc_item: Option<(Symbol, Namespace)>,
1504 found_traits: &mut Vec<TraitCandidate>,
1506 module.ensure_traits(self);
1507 let traits = module.traits.borrow();
1508 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1509 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1510 let def_id = trait_binding.res().def_id();
1511 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1512 found_traits.push(TraitCandidate { def_id, import_ids });
1517 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1518 // associated item with the given name and namespace (if specified). This is a conservative
1519 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1520 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1521 // associated items.
1522 fn trait_may_have_item(
1524 trait_module: Option<Module<'a>>,
1525 assoc_item: Option<(Symbol, Namespace)>,
1527 match (trait_module, assoc_item) {
1528 (Some(trait_module), Some((name, ns))) => {
1529 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1530 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1531 assoc_ns == ns && assoc_ident.name == name
1538 fn find_transitive_imports(
1540 mut kind: &NameBindingKind<'_>,
1542 ) -> SmallVec<[LocalDefId; 1]> {
1543 let mut import_ids = smallvec![];
1544 while let NameBindingKind::Import { import, binding, .. } = kind {
1545 let id = self.local_def_id(import.id);
1546 self.maybe_unused_trait_imports.insert(id);
1547 self.add_to_glob_map(&import, trait_name);
1548 import_ids.push(id);
1549 kind = &binding.kind;
1558 nearest_parent_mod: DefId,
1562 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1563 self.arenas.alloc_module(module)
1566 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1567 let ident = ident.normalize_to_macros_2_0();
1568 let disambiguator = if ident.name == kw::Underscore {
1569 self.underscore_disambiguator += 1;
1570 self.underscore_disambiguator
1574 BindingKey { ident, ns, disambiguator }
1577 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1578 if module.populate_on_access.get() {
1579 module.populate_on_access.set(false);
1580 self.build_reduced_graph_external(module);
1582 &module.lazy_resolutions
1589 ) -> &'a RefCell<NameResolution<'a>> {
1591 .resolutions(module)
1594 .or_insert_with(|| self.arenas.alloc_name_resolution())
1601 used_binding: &'a NameBinding<'a>,
1602 is_lexical_scope: bool,
1604 if let Some((b2, kind)) = used_binding.ambiguity {
1605 self.ambiguity_errors.push(AmbiguityError {
1610 misc1: AmbiguityErrorMisc::None,
1611 misc2: AmbiguityErrorMisc::None,
1614 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1615 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1616 // but not introduce it, as used if they are accessed from lexical scope.
1617 if is_lexical_scope {
1618 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1619 if let Some(crate_item) = entry.extern_crate_item {
1620 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1627 import.used.set(true);
1628 self.used_imports.insert((import.id, ns));
1629 self.add_to_glob_map(&import, ident);
1630 self.record_use(ident, ns, binding, false);
1635 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1636 if import.is_glob() {
1637 let def_id = self.local_def_id(import.id);
1638 self.glob_map.entry(def_id).or_default().insert(ident.name);
1642 /// A generic scope visitor.
1643 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1644 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1647 scope_set: ScopeSet<'a>,
1648 parent_scope: &ParentScope<'a>,
1649 ctxt: SyntaxContext,
1650 mut visitor: impl FnMut(
1653 /*use_prelude*/ bool,
1657 // General principles:
1658 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1659 // built into the language or standard library. This way we can add new names into the
1660 // language or standard library without breaking user code.
1661 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1662 // Places to search (in order of decreasing priority):
1664 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1665 // (open set, not controlled).
1666 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1667 // (open, not controlled).
1668 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1669 // 4. Tool modules (closed, controlled right now, but not in the future).
1670 // 5. Standard library prelude (de-facto closed, controlled).
1671 // 6. Language prelude (closed, controlled).
1673 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1674 // (open set, not controlled).
1675 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1676 // (open, not controlled).
1677 // 3. Standard library prelude (de-facto closed, controlled).
1679 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1680 // are currently reported as errors. They should be higher in priority than preludes
1681 // and probably even names in modules according to the "general principles" above. They
1682 // also should be subject to restricted shadowing because are effectively produced by
1683 // derives (you need to resolve the derive first to add helpers into scope), but they
1684 // should be available before the derive is expanded for compatibility.
1685 // It's mess in general, so we are being conservative for now.
1686 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1687 // priority than prelude macros, but create ambiguities with macros in modules.
1688 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1689 // (open, not controlled). Have higher priority than prelude macros, but create
1690 // ambiguities with `macro_rules`.
1691 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1692 // 4a. User-defined prelude from macro-use
1693 // (open, the open part is from macro expansions, not controlled).
1694 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1695 // 4c. Standard library prelude (de-facto closed, controlled).
1696 // 6. Language prelude: builtin attributes (closed, controlled).
1698 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1699 let (ns, macro_kind, is_absolute_path) = match scope_set {
1700 ScopeSet::All(ns, _) => (ns, None, false),
1701 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1702 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1703 ScopeSet::Late(ns, ..) => (ns, None, false),
1705 let module = match scope_set {
1706 // Start with the specified module.
1707 ScopeSet::Late(_, module, _) => module,
1708 // Jump out of trait or enum modules, they do not act as scopes.
1709 _ => parent_scope.module.nearest_item_scope(),
1711 let mut scope = match ns {
1712 _ if is_absolute_path => Scope::CrateRoot,
1713 TypeNS | ValueNS => Scope::Module(module, None),
1714 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1716 let mut ctxt = ctxt.normalize_to_macros_2_0();
1717 let mut use_prelude = !module.no_implicit_prelude;
1720 let visit = match scope {
1721 // Derive helpers are not in scope when resolving derives in the same container.
1722 Scope::DeriveHelpers(expn_id) => {
1723 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1725 Scope::DeriveHelpersCompat => true,
1726 Scope::MacroRules(macro_rules_scope) => {
1727 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1728 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1729 // As another consequence of this optimization visitors never observe invocation
1730 // scopes for macros that were already expanded.
1731 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1732 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1733 macro_rules_scope.set(next_scope.get());
1740 Scope::CrateRoot => true,
1741 Scope::Module(..) => true,
1742 Scope::RegisteredAttrs => use_prelude,
1743 Scope::MacroUsePrelude => use_prelude || rust_2015,
1744 Scope::BuiltinAttrs => true,
1745 Scope::ExternPrelude => use_prelude || is_absolute_path,
1746 Scope::ToolPrelude => use_prelude,
1747 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1748 Scope::BuiltinTypes => true,
1752 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1753 return break_result;
1757 scope = match scope {
1758 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1759 // Derive helpers are not visible to code generated by bang or derive macros.
1760 let expn_data = expn_id.expn_data();
1761 match expn_data.kind {
1763 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1764 Scope::DeriveHelpersCompat
1766 _ => Scope::DeriveHelpers(expn_data.parent),
1769 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1770 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1771 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1772 MacroRulesScope::Binding(binding) => {
1773 Scope::MacroRules(binding.parent_macro_rules_scope)
1775 MacroRulesScope::Invocation(invoc_id) => {
1776 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1778 MacroRulesScope::Empty => Scope::Module(module, None),
1780 Scope::CrateRoot => match ns {
1782 ctxt.adjust(ExpnId::root());
1783 Scope::ExternPrelude
1785 ValueNS | MacroNS => break,
1787 Scope::Module(module, prev_lint_id) => {
1788 use_prelude = !module.no_implicit_prelude;
1789 let derive_fallback_lint_id = match scope_set {
1790 ScopeSet::Late(.., lint_id) => lint_id,
1793 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1794 Some((parent_module, lint_id)) => {
1795 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1798 ctxt.adjust(ExpnId::root());
1800 TypeNS => Scope::ExternPrelude,
1801 ValueNS => Scope::StdLibPrelude,
1802 MacroNS => Scope::RegisteredAttrs,
1807 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1808 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1809 Scope::BuiltinAttrs => break, // nowhere else to search
1810 Scope::ExternPrelude if is_absolute_path => break,
1811 Scope::ExternPrelude => Scope::ToolPrelude,
1812 Scope::ToolPrelude => Scope::StdLibPrelude,
1813 Scope::StdLibPrelude => match ns {
1814 TypeNS => Scope::BuiltinTypes,
1815 ValueNS => break, // nowhere else to search
1816 MacroNS => Scope::BuiltinAttrs,
1818 Scope::BuiltinTypes => break, // nowhere else to search
1825 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1826 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1827 /// `ident` in the first scope that defines it (or None if no scopes define it).
1829 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1830 /// the items are defined in the block. For example,
1833 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1836 /// g(); // This resolves to the local variable `g` since it shadows the item.
1840 /// Invariant: This must only be called during main resolution, not during
1841 /// import resolution.
1842 fn resolve_ident_in_lexical_scope(
1846 parent_scope: &ParentScope<'a>,
1847 record_used_id: Option<NodeId>,
1850 ) -> Option<LexicalScopeBinding<'a>> {
1851 assert!(ns == TypeNS || ns == ValueNS);
1852 let orig_ident = ident;
1853 if ident.name == kw::Empty {
1854 return Some(LexicalScopeBinding::Res(Res::Err));
1856 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1857 // FIXME(jseyfried) improve `Self` hygiene
1858 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1859 (empty_span, empty_span)
1860 } else if ns == TypeNS {
1861 let normalized_span = ident.span.normalize_to_macros_2_0();
1862 (normalized_span, normalized_span)
1864 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1866 ident.span = general_span;
1867 let normalized_ident = Ident { span: normalized_span, ..ident };
1869 // Walk backwards up the ribs in scope.
1870 let record_used = record_used_id.is_some();
1871 let mut module = self.graph_root;
1872 for i in (0..ribs.len()).rev() {
1873 debug!("walk rib\n{:?}", ribs[i].bindings);
1874 // Use the rib kind to determine whether we are resolving parameters
1875 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1876 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1877 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1879 // The ident resolves to a type parameter or local variable.
1880 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1886 *original_rib_ident_def,
1891 module = match ribs[i].kind {
1892 ModuleRibKind(module) => module,
1893 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1894 // If an invocation of this macro created `ident`, give up on `ident`
1895 // and switch to `ident`'s source from the macro definition.
1896 ident.span.remove_mark();
1903 ModuleKind::Block(..) => {} // We can see through blocks
1907 let item = self.resolve_ident_in_module_unadjusted(
1908 ModuleOrUniformRoot::Module(module),
1915 if let Ok(binding) = item {
1916 // The ident resolves to an item.
1917 return Some(LexicalScopeBinding::Item(binding));
1921 self.early_resolve_ident_in_lexical_scope(
1923 ScopeSet::Late(ns, module, record_used_id),
1930 .map(LexicalScopeBinding::Item)
1933 fn hygienic_lexical_parent(
1936 ctxt: &mut SyntaxContext,
1937 derive_fallback_lint_id: Option<NodeId>,
1938 ) -> Option<(Module<'a>, Option<NodeId>)> {
1939 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
1940 return Some((self.macro_def_scope(ctxt.remove_mark()), None));
1943 if let ModuleKind::Block(..) = module.kind {
1944 return Some((module.parent.unwrap().nearest_item_scope(), None));
1947 // We need to support the next case under a deprecation warning
1950 // ---- begin: this comes from a proc macro derive
1951 // mod implementation_details {
1952 // // Note that `MyStruct` is not in scope here.
1953 // impl SomeTrait for MyStruct { ... }
1957 // So we have to fall back to the module's parent during lexical resolution in this case.
1958 if derive_fallback_lint_id.is_some() {
1959 if let Some(parent) = module.parent {
1960 // Inner module is inside the macro, parent module is outside of the macro.
1961 if module.expansion != parent.expansion
1962 && module.expansion.is_descendant_of(parent.expansion)
1964 // The macro is a proc macro derive
1965 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
1966 let ext = self.get_macro_by_def_id(def_id);
1967 if ext.builtin_name.is_none()
1968 && ext.macro_kind() == MacroKind::Derive
1969 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
1971 return Some((parent, derive_fallback_lint_id));
1981 fn resolve_ident_in_module(
1983 module: ModuleOrUniformRoot<'a>,
1986 parent_scope: &ParentScope<'a>,
1989 ) -> Result<&'a NameBinding<'a>, Determinacy> {
1990 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
1991 .map_err(|(determinacy, _)| determinacy)
1994 fn resolve_ident_in_module_ext(
1996 module: ModuleOrUniformRoot<'a>,
1999 parent_scope: &ParentScope<'a>,
2002 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2003 let tmp_parent_scope;
2004 let mut adjusted_parent_scope = parent_scope;
2006 ModuleOrUniformRoot::Module(m) => {
2007 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2009 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2010 adjusted_parent_scope = &tmp_parent_scope;
2013 ModuleOrUniformRoot::ExternPrelude => {
2014 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2016 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2020 self.resolve_ident_in_module_unadjusted_ext(
2024 adjusted_parent_scope,
2031 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2032 debug!("resolve_crate_root({:?})", ident);
2033 let mut ctxt = ident.span.ctxt();
2034 let mark = if ident.name == kw::DollarCrate {
2035 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2036 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2037 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2038 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2039 // definitions actually produced by `macro` and `macro` definitions produced by
2040 // `macro_rules!`, but at least such configurations are not stable yet.
2041 ctxt = ctxt.normalize_to_macro_rules();
2043 "resolve_crate_root: marks={:?}",
2044 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2046 let mut iter = ctxt.marks().into_iter().rev().peekable();
2047 let mut result = None;
2048 // Find the last opaque mark from the end if it exists.
2049 while let Some(&(mark, transparency)) = iter.peek() {
2050 if transparency == Transparency::Opaque {
2051 result = Some(mark);
2058 "resolve_crate_root: found opaque mark {:?} {:?}",
2060 result.map(|r| r.expn_data())
2062 // Then find the last semi-transparent mark from the end if it exists.
2063 for (mark, transparency) in iter {
2064 if transparency == Transparency::SemiTransparent {
2065 result = Some(mark);
2071 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2073 result.map(|r| r.expn_data())
2077 debug!("resolve_crate_root: not DollarCrate");
2078 ctxt = ctxt.normalize_to_macros_2_0();
2079 ctxt.adjust(ExpnId::root())
2081 let module = match mark {
2082 Some(def) => self.macro_def_scope(def),
2085 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2088 return self.graph_root;
2091 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2093 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2102 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2103 let mut module = self.get_module(module.nearest_parent_mod);
2104 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2105 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2106 module = self.get_module(parent.nearest_parent_mod);
2114 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2115 parent_scope: &ParentScope<'a>,
2118 crate_lint: CrateLint,
2119 ) -> PathResult<'a> {
2120 self.resolve_path_with_ribs(
2131 fn resolve_path_with_ribs(
2134 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2135 parent_scope: &ParentScope<'a>,
2138 crate_lint: CrateLint,
2139 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2140 ) -> PathResult<'a> {
2141 let mut module = None;
2142 let mut allow_super = true;
2143 let mut second_binding = None;
2146 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2147 path_span={:?}, crate_lint={:?})",
2148 path, opt_ns, record_used, path_span, crate_lint,
2151 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2152 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2153 let record_segment_res = |this: &mut Self, res| {
2155 if let Some(id) = id {
2156 if !this.partial_res_map.contains_key(&id) {
2157 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2158 this.record_partial_res(id, PartialRes::new(res));
2164 let is_last = i == path.len() - 1;
2165 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2166 let name = ident.name;
2168 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2171 if allow_super && name == kw::Super {
2172 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2173 let self_module = match i {
2174 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2176 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2180 if let Some(self_module) = self_module {
2181 if let Some(parent) = self_module.parent {
2182 module = Some(ModuleOrUniformRoot::Module(
2183 self.resolve_self(&mut ctxt, parent),
2188 let msg = "there are too many leading `super` keywords".to_string();
2189 return PathResult::Failed {
2193 is_error_from_last_segment: false,
2197 if name == kw::SelfLower {
2198 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2199 module = Some(ModuleOrUniformRoot::Module(
2200 self.resolve_self(&mut ctxt, parent_scope.module),
2204 if name == kw::PathRoot && ident.span.rust_2018() {
2205 module = Some(ModuleOrUniformRoot::ExternPrelude);
2208 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2209 // `::a::b` from 2015 macro on 2018 global edition
2210 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2213 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2214 // `::a::b`, `crate::a::b` or `$crate::a::b`
2215 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2221 // Report special messages for path segment keywords in wrong positions.
2222 if ident.is_path_segment_keyword() && i != 0 {
2223 let name_str = if name == kw::PathRoot {
2224 "crate root".to_string()
2226 format!("`{}`", name)
2228 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2229 format!("global paths cannot start with {}", name_str)
2231 format!("{} in paths can only be used in start position", name_str)
2233 return PathResult::Failed {
2237 is_error_from_last_segment: false,
2241 enum FindBindingResult<'a> {
2242 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2243 PathResult(PathResult<'a>),
2245 let find_binding_in_ns = |this: &mut Self, ns| {
2246 let binding = if let Some(module) = module {
2247 this.resolve_ident_in_module(
2255 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2256 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2257 this.early_resolve_ident_in_lexical_scope(
2266 let record_used_id = if record_used {
2267 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2271 match this.resolve_ident_in_lexical_scope(
2279 // we found a locally-imported or available item/module
2280 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2281 // we found a local variable or type param
2282 Some(LexicalScopeBinding::Res(res))
2283 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2285 record_segment_res(this, res);
2286 return FindBindingResult::PathResult(PathResult::NonModule(
2287 PartialRes::with_unresolved_segments(res, path.len() - 1),
2290 _ => Err(Determinacy::determined(record_used)),
2293 FindBindingResult::Binding(binding)
2295 let binding = match find_binding_in_ns(self, ns) {
2296 FindBindingResult::PathResult(x) => return x,
2297 FindBindingResult::Binding(binding) => binding,
2302 second_binding = Some(binding);
2304 let res = binding.res();
2305 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2306 if let Some(next_module) = binding.module() {
2307 module = Some(ModuleOrUniformRoot::Module(next_module));
2308 record_segment_res(self, res);
2309 } else if res == Res::ToolMod && i + 1 != path.len() {
2310 if binding.is_import() {
2314 "cannot use a tool module through an import",
2316 .span_note(binding.span, "the tool module imported here")
2319 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2320 return PathResult::NonModule(PartialRes::new(res));
2321 } else if res == Res::Err {
2322 return PathResult::NonModule(PartialRes::new(Res::Err));
2323 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2324 self.lint_if_path_starts_with_module(
2330 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2335 let label = format!(
2336 "`{}` is {} {}, not a module",
2342 return PathResult::Failed {
2346 is_error_from_last_segment: is_last,
2350 Err(Undetermined) => return PathResult::Indeterminate,
2351 Err(Determined) => {
2352 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2353 if opt_ns.is_some() && !module.is_normal() {
2354 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2355 module.res().unwrap(),
2360 let module_res = match module {
2361 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2364 let (label, suggestion) = if module_res == self.graph_root.res() {
2365 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2366 // Don't look up import candidates if this is a speculative resolve
2367 let mut candidates = if record_used {
2368 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2372 candidates.sort_by_cached_key(|c| {
2373 (c.path.segments.len(), pprust::path_to_string(&c.path))
2375 if let Some(candidate) = candidates.get(0) {
2377 String::from("unresolved import"),
2379 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2380 String::from("a similar path exists"),
2381 Applicability::MaybeIncorrect,
2384 } else if self.session.edition() == Edition::Edition2015 {
2385 (format!("maybe a missing crate `{}`?", ident), None)
2387 (format!("could not find `{}` in the crate root", ident), None)
2395 .map_or(false, |c| c.is_ascii_uppercase())
2397 (format!("use of undeclared type `{}`", ident), None)
2399 (format!("use of undeclared crate or module `{}`", ident), None)
2402 let parent = path[i - 1].ident.name;
2403 let parent = match parent {
2404 // ::foo is mounted at the crate root for 2015, and is the extern
2405 // prelude for 2018+
2406 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2407 "the list of imported crates".to_owned()
2409 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2411 format!("`{}`", parent)
2415 let mut msg = format!("could not find `{}` in {}", ident, parent);
2416 if ns == TypeNS || ns == ValueNS {
2417 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2418 if let FindBindingResult::Binding(Ok(binding)) =
2419 find_binding_in_ns(self, ns_to_try)
2421 let mut found = |what| {
2423 "expected {}, found {} `{}` in {}",
2430 if binding.module().is_some() {
2433 match binding.res() {
2434 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2435 _ => found(ns_to_try.descr()),
2442 return PathResult::Failed {
2446 is_error_from_last_segment: is_last,
2452 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2454 PathResult::Module(match module {
2455 Some(module) => module,
2456 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2457 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2461 fn lint_if_path_starts_with_module(
2463 crate_lint: CrateLint,
2466 second_binding: Option<&NameBinding<'_>>,
2468 let (diag_id, diag_span) = match crate_lint {
2469 CrateLint::No => return,
2470 CrateLint::SimplePath(id) => (id, path_span),
2471 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2472 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2475 let first_name = match path.get(0) {
2476 // In the 2018 edition this lint is a hard error, so nothing to do
2477 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2481 // We're only interested in `use` paths which should start with
2482 // `{{root}}` currently.
2483 if first_name != kw::PathRoot {
2488 // If this import looks like `crate::...` it's already good
2489 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2490 // Otherwise go below to see if it's an extern crate
2492 // If the path has length one (and it's `PathRoot` most likely)
2493 // then we don't know whether we're gonna be importing a crate or an
2494 // item in our crate. Defer this lint to elsewhere
2498 // If the first element of our path was actually resolved to an
2499 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2500 // warning, this looks all good!
2501 if let Some(binding) = second_binding {
2502 if let NameBindingKind::Import { import, .. } = binding.kind {
2503 // Careful: we still want to rewrite paths from renamed extern crates.
2504 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2510 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2511 self.lint_buffer.buffer_lint_with_diagnostic(
2512 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2515 "absolute paths must start with `self`, `super`, \
2516 `crate`, or an external crate name in the 2018 edition",
2521 // Validate a local resolution (from ribs).
2522 fn validate_res_from_ribs(
2529 original_rib_ident_def: Ident,
2530 all_ribs: &[Rib<'a>],
2532 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2533 debug!("validate_res_from_ribs({:?})", res);
2534 let ribs = &all_ribs[rib_index + 1..];
2536 // An invalid forward use of a generic parameter from a previous default.
2537 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2539 let res_error = if rib_ident.name == kw::SelfUpper {
2540 ResolutionError::SelfInTyParamDefault
2542 ResolutionError::ForwardDeclaredTyParam
2544 self.report_error(span, res_error);
2546 assert_eq!(res, Res::Err);
2552 use ResolutionError::*;
2553 let mut res_err = None;
2558 | ClosureOrAsyncRibKind
2560 | MacroDefinition(..)
2561 | ForwardGenericParamBanRibKind => {
2562 // Nothing to do. Continue.
2564 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2565 // This was an attempt to access an upvar inside a
2566 // named function item. This is not allowed, so we
2569 // We don't immediately trigger a resolve error, because
2570 // we want certain other resolution errors (namely those
2571 // emitted for `ConstantItemRibKind` below) to take
2573 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2576 ConstantItemRibKind(_, item) => {
2577 // Still doesn't deal with upvars
2579 let (span, resolution_error) =
2580 if let Some((ident, constant_item_kind)) = item {
2581 let kind_str = match constant_item_kind {
2582 ConstantItemKind::Const => "const",
2583 ConstantItemKind::Static => "static",
2587 AttemptToUseNonConstantValueInConstant(
2588 ident, "let", kind_str,
2594 AttemptToUseNonConstantValueInConstant(
2595 original_rib_ident_def,
2601 self.report_error(span, resolution_error);
2605 ConstParamTyRibKind => {
2607 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2613 if let Some(res_err) = res_err {
2614 self.report_error(span, res_err);
2618 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2619 let mut in_ty_param_default = false;
2621 let has_generic_params = match rib.kind {
2623 | ClosureOrAsyncRibKind
2626 | MacroDefinition(..) => {
2627 // Nothing to do. Continue.
2631 // We only forbid constant items if we are inside of type defaults,
2632 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2633 ForwardGenericParamBanRibKind => {
2634 // FIXME(const_generic_defaults): we may need to distinguish between
2635 // being in type parameter defaults and const parameter defaults
2636 in_ty_param_default = true;
2639 ConstantItemRibKind(trivial, _) => {
2640 let features = self.session.features_untracked();
2641 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2643 || features.const_generics
2644 || features.lazy_normalization_consts)
2646 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2647 // we can't easily tell if it's generic at this stage, so we instead remember
2648 // this and then enforce the self type to be concrete later on.
2649 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2650 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2655 ResolutionError::ParamInNonTrivialAnonConst {
2656 name: rib_ident.name,
2662 self.session.delay_span_bug(span, CG_BUG_STR);
2667 if in_ty_param_default {
2671 ResolutionError::ParamInAnonConstInTyDefault(
2682 // This was an attempt to use a type parameter outside its scope.
2683 ItemRibKind(has_generic_params) => has_generic_params,
2684 FnItemRibKind => HasGenericParams::Yes,
2685 ConstParamTyRibKind => {
2689 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2699 ResolutionError::GenericParamsFromOuterFunction(
2708 Res::Def(DefKind::ConstParam, _) => {
2709 let mut ribs = ribs.iter().peekable();
2710 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2711 // When declaring const parameters inside function signatures, the first rib
2712 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2713 // (spuriously) conflicting with the const param.
2717 let mut in_ty_param_default = false;
2719 let has_generic_params = match rib.kind {
2721 | ClosureOrAsyncRibKind
2724 | MacroDefinition(..) => continue,
2726 // We only forbid constant items if we are inside of type defaults,
2727 // for example `struct Foo<T, U = [u8; std::mem::size_of::<T>()]>`
2728 ForwardGenericParamBanRibKind => {
2729 // FIXME(const_generic_defaults): we may need to distinguish between
2730 // being in type parameter defaults and const parameter defaults
2731 in_ty_param_default = true;
2734 ConstantItemRibKind(trivial, _) => {
2735 let features = self.session.features_untracked();
2736 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2738 || features.const_generics
2739 || features.lazy_normalization_consts)
2744 ResolutionError::ParamInNonTrivialAnonConst {
2745 name: rib_ident.name,
2751 self.session.delay_span_bug(span, CG_BUG_STR);
2755 if in_ty_param_default {
2759 ResolutionError::ParamInAnonConstInTyDefault(
2770 ItemRibKind(has_generic_params) => has_generic_params,
2771 FnItemRibKind => HasGenericParams::Yes,
2772 ConstParamTyRibKind => {
2776 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2783 // This was an attempt to use a const parameter outside its scope.
2787 ResolutionError::GenericParamsFromOuterFunction(
2801 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2802 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2803 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2804 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2808 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2809 vis.is_accessible_from(module.nearest_parent_mod, self)
2812 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2813 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2814 if !ptr::eq(module, old_module) {
2815 span_bug!(binding.span, "parent module is reset for binding");
2820 fn disambiguate_macro_rules_vs_modularized(
2822 macro_rules: &'a NameBinding<'a>,
2823 modularized: &'a NameBinding<'a>,
2825 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2826 // is disambiguated to mitigate regressions from macro modularization.
2827 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2829 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2830 self.binding_parent_modules.get(&PtrKey(modularized)),
2832 (Some(macro_rules), Some(modularized)) => {
2833 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2834 && modularized.is_ancestor_of(macro_rules)
2840 fn report_errors(&mut self, krate: &Crate) {
2841 self.report_with_use_injections(krate);
2843 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2844 let msg = "macro-expanded `macro_export` macros from the current crate \
2845 cannot be referred to by absolute paths";
2846 self.lint_buffer.buffer_lint_with_diagnostic(
2847 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2851 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2855 for ambiguity_error in &self.ambiguity_errors {
2856 self.report_ambiguity_error(ambiguity_error);
2859 let mut reported_spans = FxHashSet::default();
2860 for error in &self.privacy_errors {
2861 if reported_spans.insert(error.dedup_span) {
2862 self.report_privacy_error(error);
2867 fn report_with_use_injections(&mut self, krate: &Crate) {
2868 for UseError { mut err, candidates, def_id, instead, suggestion } in
2869 self.use_injections.drain(..)
2871 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2872 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2876 if !candidates.is_empty() {
2877 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2878 } else if let Some((span, msg, sugg, appl)) = suggestion {
2879 err.span_suggestion(span, msg, sugg, appl);
2885 fn report_conflict<'b>(
2890 new_binding: &NameBinding<'b>,
2891 old_binding: &NameBinding<'b>,
2893 // Error on the second of two conflicting names
2894 if old_binding.span.lo() > new_binding.span.lo() {
2895 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2898 let container = match parent.kind {
2899 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2900 ModuleKind::Block(..) => "block",
2903 let old_noun = match old_binding.is_import() {
2905 false => "definition",
2908 let new_participle = match new_binding.is_import() {
2914 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2916 if let Some(s) = self.name_already_seen.get(&name) {
2922 let old_kind = match (ns, old_binding.module()) {
2923 (ValueNS, _) => "value",
2924 (MacroNS, _) => "macro",
2925 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2926 (TypeNS, Some(module)) if module.is_normal() => "module",
2927 (TypeNS, Some(module)) if module.is_trait() => "trait",
2928 (TypeNS, _) => "type",
2931 let msg = format!("the name `{}` is defined multiple times", name);
2933 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2934 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2935 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2936 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2937 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2939 _ => match (old_binding.is_import(), new_binding.is_import()) {
2940 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2941 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2942 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2947 "`{}` must be defined only once in the {} namespace of this {}",
2953 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2955 self.session.source_map().guess_head_span(old_binding.span),
2956 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2959 // See https://github.com/rust-lang/rust/issues/32354
2960 use NameBindingKind::Import;
2961 let import = match (&new_binding.kind, &old_binding.kind) {
2962 // If there are two imports where one or both have attributes then prefer removing the
2963 // import without attributes.
2964 (Import { import: new, .. }, Import { import: old, .. })
2966 !new_binding.span.is_dummy()
2967 && !old_binding.span.is_dummy()
2968 && (new.has_attributes || old.has_attributes)
2971 if old.has_attributes {
2972 Some((new, new_binding.span, true))
2974 Some((old, old_binding.span, true))
2977 // Otherwise prioritize the new binding.
2978 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
2979 Some((import, new_binding.span, other.is_import()))
2981 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
2982 Some((import, old_binding.span, other.is_import()))
2987 // Check if the target of the use for both bindings is the same.
2988 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
2989 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
2991 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
2992 // Only suggest removing an import if both bindings are to the same def, if both spans
2993 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
2994 // been introduced by a item.
2995 let should_remove_import = duplicate
2997 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3000 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3001 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3003 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3004 // Simple case - remove the entire import. Due to the above match arm, this can
3005 // only be a single use so just remove it entirely.
3006 err.tool_only_span_suggestion(
3007 import.use_span_with_attributes,
3008 "remove unnecessary import",
3010 Applicability::MaybeIncorrect,
3013 Some((import, span, _)) => {
3014 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3020 self.name_already_seen.insert(name, span);
3023 /// This function adds a suggestion to change the binding name of a new import that conflicts
3024 /// with an existing import.
3026 /// ```text,ignore (diagnostic)
3027 /// help: you can use `as` to change the binding name of the import
3029 /// LL | use foo::bar as other_bar;
3030 /// | ^^^^^^^^^^^^^^^^^^^^^
3032 fn add_suggestion_for_rename_of_use(
3034 err: &mut DiagnosticBuilder<'_>,
3036 import: &Import<'_>,
3039 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3040 format!("Other{}", name)
3042 format!("other_{}", name)
3045 let mut suggestion = None;
3047 ImportKind::Single { type_ns_only: true, .. } => {
3048 suggestion = Some(format!("self as {}", suggested_name))
3050 ImportKind::Single { source, .. } => {
3052 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3054 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3055 if pos <= snippet.len() {
3056 suggestion = Some(format!(
3060 if snippet.ends_with(';') { ";" } else { "" }
3066 ImportKind::ExternCrate { source, target, .. } => {
3067 suggestion = Some(format!(
3068 "extern crate {} as {};",
3069 source.unwrap_or(target.name),
3073 _ => unreachable!(),
3076 let rename_msg = "you can use `as` to change the binding name of the import";
3077 if let Some(suggestion) = suggestion {
3078 err.span_suggestion(
3082 Applicability::MaybeIncorrect,
3085 err.span_label(binding_span, rename_msg);
3089 /// This function adds a suggestion to remove a unnecessary binding from an import that is
3090 /// nested. In the following example, this function will be invoked to remove the `a` binding
3091 /// in the second use statement:
3093 /// ```ignore (diagnostic)
3094 /// use issue_52891::a;
3095 /// use issue_52891::{d, a, e};
3098 /// The following suggestion will be added:
3100 /// ```ignore (diagnostic)
3101 /// use issue_52891::{d, a, e};
3102 /// ^-- help: remove unnecessary import
3105 /// If the nested use contains only one import then the suggestion will remove the entire
3108 /// It is expected that the provided import is nested - this isn't checked by the
3109 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3110 /// as characters expected by span manipulations won't be present.
3111 fn add_suggestion_for_duplicate_nested_use(
3113 err: &mut DiagnosticBuilder<'_>,
3114 import: &Import<'_>,
3117 assert!(import.is_nested());
3118 let message = "remove unnecessary import";
3120 // Two examples will be used to illustrate the span manipulations we're doing:
3122 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3123 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3124 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3125 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3127 let (found_closing_brace, span) =
3128 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3130 // If there was a closing brace then identify the span to remove any trailing commas from
3131 // previous imports.
3132 if found_closing_brace {
3133 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3134 err.tool_only_span_suggestion(
3138 Applicability::MaybeIncorrect,
3141 // Remove the entire line if we cannot extend the span back, this indicates a
3142 // `issue_52891::{self}` case.
3143 err.span_suggestion(
3144 import.use_span_with_attributes,
3147 Applicability::MaybeIncorrect,
3154 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3157 fn extern_prelude_get(
3161 ) -> Option<&'a NameBinding<'a>> {
3162 if ident.is_path_segment_keyword() {
3163 // Make sure `self`, `super` etc produce an error when passed to here.
3166 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3167 if let Some(binding) = entry.extern_crate_item {
3168 if !speculative && entry.introduced_by_item {
3169 self.record_use(ident, TypeNS, binding, false);
3173 let crate_id = if !speculative {
3174 self.crate_loader.process_path_extern(ident.name, ident.span)
3176 self.crate_loader.maybe_process_path_extern(ident.name)?
3178 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3180 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3181 .to_name_binding(self.arenas),
3187 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3188 /// isn't something that can be returned because it can't be made to live that long,
3189 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3190 /// just that an error occurred.
3191 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3192 pub fn resolve_str_path_error(
3198 ) -> Result<(ast::Path, Res), ()> {
3199 let path = if path_str.starts_with("::") {
3202 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3203 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3204 .map(|i| self.new_ast_path_segment(i))
3213 .map(Ident::from_str)
3214 .map(|i| self.new_ast_path_segment(i))
3219 let module = self.get_module(module_id);
3220 let parent_scope = &ParentScope::module(module, self);
3221 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3225 // Resolve a path passed from rustdoc or HIR lowering.
3226 fn resolve_ast_path(
3230 parent_scope: &ParentScope<'a>,
3231 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3232 match self.resolve_path(
3233 &Segment::from_path(path),
3240 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3241 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3242 Ok(path_res.base_res())
3244 PathResult::NonModule(..) => Err((
3246 ResolutionError::FailedToResolve {
3247 label: String::from("type-relative paths are not supported in this context"),
3251 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3252 PathResult::Failed { span, label, suggestion, .. } => {
3253 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3258 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3259 let mut seg = ast::PathSegment::from_ident(ident);
3260 seg.id = self.next_node_id();
3265 pub fn graph_root(&self) -> Module<'a> {
3270 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3274 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3276 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3277 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3280 /// Checks if an expression refers to a function marked with
3281 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3282 /// from the attribute.
3283 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3284 if let ExprKind::Path(None, path) = &expr.kind {
3285 // Don't perform legacy const generics rewriting if the path already
3286 // has generic arguments.
3287 if path.segments.last().unwrap().args.is_some() {
3291 let partial_res = self.partial_res_map.get(&expr.id)?;
3292 if partial_res.unresolved_segments() != 0 {
3296 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3297 // We only support cross-crate argument rewriting. Uses
3298 // within the same crate should be updated to use the new
3299 // const generics style.
3300 if def_id.is_local() {
3304 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3308 let parse_attrs = || {
3309 let attrs = self.cstore().item_attrs(def_id, self.session);
3312 .find(|a| self.session.check_name(a, sym::rustc_legacy_const_generics))?;
3313 let mut ret = vec![];
3314 for meta in attr.meta_item_list()? {
3315 match meta.literal()?.kind {
3316 LitKind::Int(a, _) => {
3317 ret.push(a as usize);
3319 _ => panic!("invalid arg index"),
3325 // Cache the lookup to avoid parsing attributes for an iterm
3327 let ret = parse_attrs();
3328 self.legacy_const_generic_args.insert(def_id, ret.clone());
3336 fn names_to_string(names: &[Symbol]) -> String {
3337 let mut result = String::new();
3338 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3340 result.push_str("::");
3342 if Ident::with_dummy_span(*name).is_raw_guess() {
3343 result.push_str("r#");
3345 result.push_str(&name.as_str());
3350 fn path_names_to_string(path: &Path) -> String {
3351 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3354 /// A somewhat inefficient routine to obtain the name of a module.
3355 fn module_to_string(module: Module<'_>) -> Option<String> {
3356 let mut names = Vec::new();
3358 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3359 if let ModuleKind::Def(.., name) = module.kind {
3360 if let Some(parent) = module.parent {
3362 collect_mod(names, parent);
3365 names.push(Symbol::intern("<opaque>"));
3366 collect_mod(names, module.parent.unwrap());
3369 collect_mod(&mut names, module);
3371 if names.is_empty() {
3375 Some(names_to_string(&names))
3378 #[derive(Copy, Clone, Debug)]
3380 /// Do not issue the lint.
3383 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3384 /// In this case, we can take the span of that path.
3387 /// This lint comes from a `use` statement. In this case, what we
3388 /// care about really is the *root* `use` statement; e.g., if we
3389 /// have nested things like `use a::{b, c}`, we care about the
3391 UsePath { root_id: NodeId, root_span: Span },
3393 /// This is the "trait item" from a fully qualified path. For example,
3394 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3395 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3396 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3400 fn node_id(&self) -> Option<NodeId> {
3402 CrateLint::No => None,
3403 CrateLint::SimplePath(id)
3404 | CrateLint::UsePath { root_id: id, .. }
3405 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3410 pub fn provide(providers: &mut Providers) {
3411 late::lifetimes::provide(providers);