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 `rustc_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(crate_visibility_modifier)]
15 #![feature(format_args_capture)]
18 #![recursion_limit = "256"]
19 #![allow(rustdoc::private_intra_doc_links)]
21 pub use rustc_hir::def::{Namespace, PerNS};
25 use rustc_arena::{DroplessArena, TypedArena};
26 use rustc_ast::node_id::NodeMap;
27 use rustc_ast::ptr::P;
28 use rustc_ast::visit::{self, Visitor};
29 use rustc_ast::{self as ast, NodeId};
30 use rustc_ast::{Crate, CRATE_NODE_ID};
31 use rustc_ast::{Expr, ExprKind, LitKind};
32 use rustc_ast::{ItemKind, ModKind, Path};
33 use rustc_ast_lowering::ResolverAstLowering;
34 use rustc_ast_pretty::pprust;
35 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
36 use rustc_data_structures::ptr_key::PtrKey;
37 use rustc_data_structures::sync::Lrc;
38 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
39 use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
40 use rustc_hir::def::Namespace::*;
41 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
42 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId, CRATE_DEF_INDEX};
43 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
44 use rustc_hir::TraitCandidate;
45 use rustc_index::vec::IndexVec;
46 use rustc_metadata::creader::{CStore, CrateLoader};
47 use rustc_middle::hir::exports::ExportMap;
48 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
49 use rustc_middle::span_bug;
50 use rustc_middle::ty::query::Providers;
51 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
52 use rustc_session::lint;
53 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
54 use rustc_session::Session;
55 use rustc_span::edition::Edition;
56 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext, Transparency};
57 use rustc_span::source_map::{CachingSourceMapView, Spanned};
58 use rustc_span::symbol::{kw, sym, Ident, Symbol};
59 use rustc_span::{Span, DUMMY_SP};
61 use smallvec::{smallvec, SmallVec};
62 use std::cell::{Cell, RefCell};
63 use std::collections::{BTreeMap, BTreeSet};
64 use std::ops::ControlFlow;
65 use std::{cmp, fmt, iter, ptr};
68 use diagnostics::{extend_span_to_previous_binding, find_span_of_binding_until_next_binding};
69 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
70 use imports::{Import, ImportKind, ImportResolver, NameResolution};
71 use late::{ConstantItemKind, HasGenericParams, PathSource, Rib, RibKind::*};
72 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
74 type Res = def::Res<NodeId>;
76 mod build_reduced_graph;
89 #[derive(Copy, Clone, PartialEq, Debug)]
90 pub enum Determinacy {
96 fn determined(determined: bool) -> Determinacy {
97 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
101 /// A specific scope in which a name can be looked up.
102 /// This enum is currently used only for early resolution (imports and macros),
103 /// but not for late resolution yet.
104 #[derive(Clone, Copy)]
106 DeriveHelpers(LocalExpnId),
108 MacroRules(MacroRulesScopeRef<'a>),
110 // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
111 // lint if it should be reported.
112 Module(Module<'a>, Option<NodeId>),
122 /// Names from different contexts may want to visit different subsets of all specific scopes
123 /// with different restrictions when looking up the resolution.
124 /// This enum is currently used only for early resolution (imports and macros),
125 /// but not for late resolution yet.
126 #[derive(Clone, Copy)]
128 /// All scopes with the given namespace.
129 All(Namespace, /*is_import*/ bool),
130 /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
131 AbsolutePath(Namespace),
132 /// All scopes with macro namespace and the given macro kind restriction.
134 /// All scopes with the given namespace, used for partially performing late resolution.
135 /// The node id enables lints and is used for reporting them.
136 Late(Namespace, Module<'a>, Option<NodeId>),
139 /// Everything you need to know about a name's location to resolve it.
140 /// Serves as a starting point for the scope visitor.
141 /// This struct is currently used only for early resolution (imports and macros),
142 /// but not for late resolution yet.
143 #[derive(Clone, Copy, Debug)]
144 pub struct ParentScope<'a> {
146 expansion: LocalExpnId,
147 macro_rules: MacroRulesScopeRef<'a>,
148 derives: &'a [ast::Path],
151 impl<'a> ParentScope<'a> {
152 /// Creates a parent scope with the passed argument used as the module scope component,
153 /// and other scope components set to default empty values.
154 pub fn module(module: Module<'a>, resolver: &Resolver<'a>) -> ParentScope<'a> {
157 expansion: LocalExpnId::ROOT,
158 macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty),
164 #[derive(Copy, Debug, Clone)]
165 enum ImplTraitContext {
167 Universal(LocalDefId),
171 struct BindingError {
173 origin: BTreeSet<Span>,
174 target: BTreeSet<Span>,
178 impl PartialOrd for BindingError {
179 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
180 Some(self.cmp(other))
184 impl PartialEq for BindingError {
185 fn eq(&self, other: &BindingError) -> bool {
186 self.name == other.name
190 impl Ord for BindingError {
191 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
192 self.name.cmp(&other.name)
196 enum ResolutionError<'a> {
197 /// Error E0401: can't use type or const parameters from outer function.
198 GenericParamsFromOuterFunction(Res, HasGenericParams),
199 /// Error E0403: the name is already used for a type or const parameter in this generic
201 NameAlreadyUsedInParameterList(Symbol, Span),
202 /// Error E0407: method is not a member of trait.
203 MethodNotMemberOfTrait(Symbol, &'a str),
204 /// Error E0437: type is not a member of trait.
205 TypeNotMemberOfTrait(Symbol, &'a str),
206 /// Error E0438: const is not a member of trait.
207 ConstNotMemberOfTrait(Symbol, &'a str),
208 /// Error E0408: variable `{}` is not bound in all patterns.
209 VariableNotBoundInPattern(&'a BindingError),
210 /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
211 VariableBoundWithDifferentMode(Symbol, Span),
212 /// Error E0415: identifier is bound more than once in this parameter list.
213 IdentifierBoundMoreThanOnceInParameterList(Symbol),
214 /// Error E0416: identifier is bound more than once in the same pattern.
215 IdentifierBoundMoreThanOnceInSamePattern(Symbol),
216 /// Error E0426: use of undeclared label.
217 UndeclaredLabel { name: Symbol, suggestion: Option<LabelSuggestion> },
218 /// Error E0429: `self` imports are only allowed within a `{ }` list.
219 SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span },
220 /// Error E0430: `self` import can only appear once in the list.
221 SelfImportCanOnlyAppearOnceInTheList,
222 /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
223 SelfImportOnlyInImportListWithNonEmptyPrefix,
224 /// Error E0433: failed to resolve.
225 FailedToResolve { label: String, suggestion: Option<Suggestion> },
226 /// Error E0434: can't capture dynamic environment in a fn item.
227 CannotCaptureDynamicEnvironmentInFnItem,
228 /// Error E0435: attempt to use a non-constant value in a constant.
229 AttemptToUseNonConstantValueInConstant(
231 /* suggestion */ &'static str,
232 /* current */ &'static str,
234 /// Error E0530: `X` bindings cannot shadow `Y`s.
235 BindingShadowsSomethingUnacceptable {
236 shadowing_binding_descr: &'static str,
238 participle: &'static str,
239 article: &'static str,
240 shadowed_binding_descr: &'static str,
241 shadowed_binding_span: Span,
243 /// Error E0128: generic parameters with a default cannot use forward-declared identifiers.
244 ForwardDeclaredGenericParam,
245 /// ERROR E0770: the type of const parameters must not depend on other generic parameters.
246 ParamInTyOfConstParam(Symbol),
247 /// generic parameters must not be used inside const evaluations.
249 /// This error is only emitted when using `min_const_generics`.
250 ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },
251 /// Error E0735: generic parameters with a default cannot use `Self`
252 SelfInGenericParamDefault,
253 /// Error E0767: use of unreachable label
254 UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
257 enum VisResolutionError<'a> {
258 Relative2018(Span, &'a ast::Path),
260 FailedToResolve(Span, String, Option<Suggestion>),
261 ExpectedFound(Span, String, Res),
266 /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
267 /// segments' which don't have the rest of an AST or HIR `PathSegment`.
268 #[derive(Clone, Copy, Debug)]
272 /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
273 /// nonsensical suggestions.
274 has_generic_args: bool,
278 fn from_path(path: &Path) -> Vec<Segment> {
279 path.segments.iter().map(|s| s.into()).collect()
282 fn from_ident(ident: Ident) -> Segment {
283 Segment { ident, id: None, has_generic_args: false }
286 fn names_to_string(segments: &[Segment]) -> String {
287 names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
291 impl<'a> From<&'a ast::PathSegment> for Segment {
292 fn from(seg: &'a ast::PathSegment) -> Segment {
293 Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
297 struct UsePlacementFinder {
298 target_module: NodeId,
303 impl UsePlacementFinder {
304 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
305 let mut finder = UsePlacementFinder { target_module, span: None, found_use: false };
306 if let ControlFlow::Continue(..) = finder.check_mod(&krate.items, CRATE_NODE_ID) {
307 visit::walk_crate(&mut finder, krate);
309 (finder.span, finder.found_use)
312 fn check_mod(&mut self, items: &[P<ast::Item>], node_id: NodeId) -> ControlFlow<()> {
313 if self.span.is_some() {
314 return ControlFlow::Break(());
316 if node_id != self.target_module {
317 return ControlFlow::Continue(());
319 // find a use statement
322 ItemKind::Use(..) => {
323 // don't suggest placing a use before the prelude
324 // import or other generated ones
325 if !item.span.from_expansion() {
326 self.span = Some(item.span.shrink_to_lo());
327 self.found_use = true;
328 return ControlFlow::Break(());
331 // don't place use before extern crate
332 ItemKind::ExternCrate(_) => {}
333 // but place them before the first other item
335 if self.span.map_or(true, |span| item.span < span)
336 && !item.span.from_expansion()
338 self.span = Some(item.span.shrink_to_lo());
339 // don't insert between attributes and an item
340 // find the first attribute on the item
341 // FIXME: This is broken for active attributes.
342 for attr in &item.attrs {
343 if !attr.span.is_dummy()
344 && self.span.map_or(true, |span| attr.span < span)
346 self.span = Some(attr.span.shrink_to_lo());
353 ControlFlow::Continue(())
357 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
358 fn visit_item(&mut self, item: &'tcx ast::Item) {
359 if let ItemKind::Mod(_, ModKind::Loaded(items, ..)) = &item.kind {
360 if let ControlFlow::Break(..) = self.check_mod(items, item.id) {
364 visit::walk_item(self, item);
368 /// An intermediate resolution result.
370 /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that
371 /// items are visible in their whole block, while `Res`es only from the place they are defined
374 enum LexicalScopeBinding<'a> {
375 Item(&'a NameBinding<'a>),
379 impl<'a> LexicalScopeBinding<'a> {
380 fn res(self) -> Res {
382 LexicalScopeBinding::Item(binding) => binding.res(),
383 LexicalScopeBinding::Res(res) => res,
388 #[derive(Copy, Clone, Debug)]
389 enum ModuleOrUniformRoot<'a> {
393 /// Virtual module that denotes resolution in crate root with fallback to extern prelude.
394 CrateRootAndExternPrelude,
396 /// Virtual module that denotes resolution in extern prelude.
397 /// Used for paths starting with `::` on 2018 edition.
400 /// Virtual module that denotes resolution in current scope.
401 /// Used only for resolving single-segment imports. The reason it exists is that import paths
402 /// are always split into two parts, the first of which should be some kind of module.
406 impl ModuleOrUniformRoot<'_> {
407 fn same_def(lhs: Self, rhs: Self) -> bool {
409 (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => {
410 lhs.def_id() == rhs.def_id()
413 ModuleOrUniformRoot::CrateRootAndExternPrelude,
414 ModuleOrUniformRoot::CrateRootAndExternPrelude,
416 | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude)
417 | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true,
423 #[derive(Clone, Debug)]
424 enum PathResult<'a> {
425 Module(ModuleOrUniformRoot<'a>),
426 NonModule(PartialRes),
431 suggestion: Option<Suggestion>,
432 is_error_from_last_segment: bool,
438 /// An anonymous module; e.g., just a block.
443 /// { // This is an anonymous module
444 /// f(); // This resolves to (2) as we are inside the block.
447 /// f(); // Resolves to (1)
451 /// Any module with a name.
455 /// * A normal module – either `mod from_file;` or `mod from_block { }` –
456 /// or the crate root (which is conceptually a top-level module).
457 /// Note that the crate root's [name][Self::name] will be [`kw::Empty`].
458 /// * A trait or an enum (it implicitly contains associated types, methods and variant
460 Def(DefKind, DefId, Symbol),
464 /// Get name of the module.
465 pub fn name(&self) -> Option<Symbol> {
467 ModuleKind::Block(..) => None,
468 ModuleKind::Def(.., name) => Some(*name),
473 /// A key that identifies a binding in a given `Module`.
475 /// Multiple bindings in the same module can have the same key (in a valid
476 /// program) if all but one of them come from glob imports.
477 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
479 /// The identifier for the binding, aways the `normalize_to_macros_2_0` version of the
483 /// 0 if ident is not `_`, otherwise a value that's unique to the specific
484 /// `_` in the expanded AST that introduced this binding.
488 type Resolutions<'a> = RefCell<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
490 /// One node in the tree of modules.
492 /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these:
495 /// * crate root (aka, top-level anonymous module)
498 /// * curly-braced block with statements
500 /// You can use [`ModuleData::kind`] to determine the kind of module this is.
501 pub struct ModuleData<'a> {
502 /// The direct parent module (it may not be a `mod`, however).
503 parent: Option<Module<'a>>,
504 /// What kind of module this is, because this may not be a `mod`.
507 /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
508 /// This may be the crate root.
509 nearest_parent_mod: DefId,
511 /// Mapping between names and their (possibly in-progress) resolutions in this module.
512 /// Resolutions in modules from other crates are not populated until accessed.
513 lazy_resolutions: Resolutions<'a>,
514 /// True if this is a module from other crate that needs to be populated on access.
515 populate_on_access: Cell<bool>,
517 /// Macro invocations that can expand into items in this module.
518 unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
520 /// Whether `#[no_implicit_prelude]` is active.
521 no_implicit_prelude: bool,
523 glob_importers: RefCell<Vec<&'a Import<'a>>>,
524 globs: RefCell<Vec<&'a Import<'a>>>,
526 /// Used to memoize the traits in this module for faster searches through all traits in scope.
527 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
529 /// Span of the module itself. Used for error reporting.
535 type Module<'a> = &'a ModuleData<'a>;
537 impl<'a> ModuleData<'a> {
539 parent: Option<Module<'a>>,
541 nearest_parent_mod: DefId,
549 lazy_resolutions: Default::default(),
550 populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
551 unexpanded_invocations: Default::default(),
552 no_implicit_prelude: false,
553 glob_importers: RefCell::new(Vec::new()),
554 globs: RefCell::new(Vec::new()),
555 traits: RefCell::new(None),
561 fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
563 R: AsMut<Resolver<'a>>,
564 F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>),
566 for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
567 if let Some(binding) = name_resolution.borrow().binding {
568 f(resolver, key.ident, key.ns, binding);
573 /// This modifies `self` in place. The traits will be stored in `self.traits`.
574 fn ensure_traits<R>(&'a self, resolver: &mut R)
576 R: AsMut<Resolver<'a>>,
578 let mut traits = self.traits.borrow_mut();
579 if traits.is_none() {
580 let mut collected_traits = Vec::new();
581 self.for_each_child(resolver, |_, name, ns, binding| {
585 if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() {
586 collected_traits.push((name, binding))
589 *traits = Some(collected_traits.into_boxed_slice());
593 fn res(&self) -> Option<Res> {
595 ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
600 fn def_id(&self) -> Option<DefId> {
602 ModuleKind::Def(_, def_id, _) => Some(def_id),
607 // `self` resolves to the first module ancestor that `is_normal`.
608 fn is_normal(&self) -> bool {
609 matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _))
612 fn is_trait(&self) -> bool {
613 matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _))
616 fn nearest_item_scope(&'a self) -> Module<'a> {
618 ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => {
619 self.parent.expect("enum or trait module without a parent")
625 fn is_ancestor_of(&self, mut other: &Self) -> bool {
626 while !ptr::eq(self, other) {
627 if let Some(parent) = other.parent {
637 impl<'a> fmt::Debug for ModuleData<'a> {
638 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
639 write!(f, "{:?}", self.res())
643 /// Records a possibly-private value, type, or module definition.
644 #[derive(Clone, Debug)]
645 pub struct NameBinding<'a> {
646 kind: NameBindingKind<'a>,
647 ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
648 expansion: LocalExpnId,
653 pub trait ToNameBinding<'a> {
654 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
657 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
658 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
663 #[derive(Clone, Debug)]
664 enum NameBindingKind<'a> {
665 Res(Res, /* is_macro_export */ bool),
667 Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
670 impl<'a> NameBindingKind<'a> {
671 /// Is this a name binding of an import?
672 fn is_import(&self) -> bool {
673 matches!(*self, NameBindingKind::Import { .. })
677 struct PrivacyError<'a> {
679 binding: &'a NameBinding<'a>,
683 struct UseError<'a> {
684 err: DiagnosticBuilder<'a>,
685 /// Candidates which user could `use` to access the missing type.
686 candidates: Vec<ImportSuggestion>,
687 /// The `DefId` of the module to place the use-statements in.
689 /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`).
691 /// Extra free-form suggestion.
692 suggestion: Option<(Span, &'static str, String, Applicability)>,
695 #[derive(Clone, Copy, PartialEq, Debug)]
700 MacroRulesVsModularized,
708 fn descr(self) -> &'static str {
710 AmbiguityKind::Import => "name vs any other name during import resolution",
711 AmbiguityKind::BuiltinAttr => "built-in attribute vs any other name",
712 AmbiguityKind::DeriveHelper => "derive helper attribute vs any other name",
713 AmbiguityKind::MacroRulesVsModularized => {
714 "`macro_rules` vs non-`macro_rules` from other module"
716 AmbiguityKind::GlobVsOuter => {
717 "glob import vs any other name from outer scope during import/macro resolution"
719 AmbiguityKind::GlobVsGlob => "glob import vs glob import in the same module",
720 AmbiguityKind::GlobVsExpanded => {
721 "glob import vs macro-expanded name in the same \
722 module during import/macro resolution"
724 AmbiguityKind::MoreExpandedVsOuter => {
725 "macro-expanded name vs less macro-expanded name \
726 from outer scope during import/macro resolution"
732 /// Miscellaneous bits of metadata for better ambiguity error reporting.
733 #[derive(Clone, Copy, PartialEq)]
734 enum AmbiguityErrorMisc {
741 struct AmbiguityError<'a> {
744 b1: &'a NameBinding<'a>,
745 b2: &'a NameBinding<'a>,
746 misc1: AmbiguityErrorMisc,
747 misc2: AmbiguityErrorMisc,
750 impl<'a> NameBinding<'a> {
751 fn module(&self) -> Option<Module<'a>> {
753 NameBindingKind::Module(module) => Some(module),
754 NameBindingKind::Import { binding, .. } => binding.module(),
759 fn res(&self) -> Res {
761 NameBindingKind::Res(res, _) => res,
762 NameBindingKind::Module(module) => module.res().unwrap(),
763 NameBindingKind::Import { binding, .. } => binding.res(),
767 fn is_ambiguity(&self) -> bool {
768 self.ambiguity.is_some()
770 NameBindingKind::Import { binding, .. } => binding.is_ambiguity(),
775 fn is_possibly_imported_variant(&self) -> bool {
777 NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(),
778 NameBindingKind::Res(
779 Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _),
782 NameBindingKind::Res(..) | NameBindingKind::Module(..) => false,
786 fn is_extern_crate(&self) -> bool {
788 NameBindingKind::Import {
789 import: &Import { kind: ImportKind::ExternCrate { .. }, .. },
792 NameBindingKind::Module(&ModuleData {
793 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
795 }) => def_id.index == CRATE_DEF_INDEX,
800 fn is_import(&self) -> bool {
801 matches!(self.kind, NameBindingKind::Import { .. })
804 fn is_glob_import(&self) -> bool {
806 NameBindingKind::Import { import, .. } => import.is_glob(),
811 fn is_importable(&self) -> bool {
814 Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _)
818 fn is_macro_def(&self) -> bool {
819 matches!(self.kind, NameBindingKind::Res(Res::Def(DefKind::Macro(..), _), _))
822 fn macro_kind(&self) -> Option<MacroKind> {
823 self.res().macro_kind()
826 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
827 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
828 // Then this function returns `true` if `self` may emerge from a macro *after* that
829 // in some later round and screw up our previously found resolution.
830 // See more detailed explanation in
831 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
834 invoc_parent_expansion: LocalExpnId,
835 binding: &NameBinding<'_>,
837 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
838 // Expansions are partially ordered, so "may appear after" is an inversion of
839 // "certainly appears before or simultaneously" and includes unordered cases.
840 let self_parent_expansion = self.expansion;
841 let other_parent_expansion = binding.expansion;
842 let certainly_before_other_or_simultaneously =
843 other_parent_expansion.is_descendant_of(self_parent_expansion);
844 let certainly_before_invoc_or_simultaneously =
845 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
846 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
850 #[derive(Debug, Default, Clone)]
851 pub struct ExternPreludeEntry<'a> {
852 extern_crate_item: Option<&'a NameBinding<'a>>,
853 pub introduced_by_item: bool,
856 /// Used for better errors for E0773
857 enum BuiltinMacroState {
858 NotYetSeen(SyntaxExtensionKind),
863 resolutions: DeriveResolutions,
864 helper_attrs: Vec<(usize, Ident)>,
865 has_derive_copy: bool,
868 /// The main resolver class.
870 /// This is the visitor that walks the whole crate.
871 pub struct Resolver<'a> {
872 session: &'a Session,
874 definitions: Definitions,
876 graph_root: Module<'a>,
878 prelude: Option<Module<'a>>,
879 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
881 /// N.B., this is used only for better diagnostics, not name resolution itself.
882 has_self: FxHashSet<DefId>,
884 /// Names of fields of an item `DefId` accessible with dot syntax.
885 /// Used for hints during error reporting.
886 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
888 /// All imports known to succeed or fail.
889 determined_imports: Vec<&'a Import<'a>>,
891 /// All non-determined imports.
892 indeterminate_imports: Vec<&'a Import<'a>>,
894 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
895 /// We are resolving a last import segment during import validation.
896 last_import_segment: bool,
897 /// This binding should be ignored during in-module resolution, so that we don't get
898 /// "self-confirming" import resolutions during import validation.
899 unusable_binding: Option<&'a NameBinding<'a>>,
901 // Spans for local variables found during pattern resolution.
902 // Used for suggestions during error reporting.
903 pat_span_map: NodeMap<Span>,
905 /// Resolutions for nodes that have a single resolution.
906 partial_res_map: NodeMap<PartialRes>,
907 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
908 import_res_map: NodeMap<PerNS<Option<Res>>>,
909 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
910 label_res_map: NodeMap<NodeId>,
912 /// `CrateNum` resolutions of `extern crate` items.
913 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
914 export_map: ExportMap<LocalDefId>,
915 trait_map: Option<NodeMap<Vec<TraitCandidate>>>,
917 /// A map from nodes to anonymous modules.
918 /// Anonymous modules are pseudo-modules that are implicitly created around items
919 /// contained within blocks.
921 /// For example, if we have this:
929 /// There will be an anonymous module created around `g` with the ID of the
930 /// entry block for `f`.
931 block_map: NodeMap<Module<'a>>,
932 /// A fake module that contains no definition and no prelude. Used so that
933 /// some AST passes can generate identifiers that only resolve to local or
935 empty_module: Module<'a>,
936 module_map: FxHashMap<LocalDefId, Module<'a>>,
937 extern_module_map: FxHashMap<DefId, Module<'a>>,
938 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
939 underscore_disambiguator: u32,
941 /// Maps glob imports to the names of items actually imported.
942 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
943 /// Visibilities in "lowered" form, for all entities that have them.
944 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
945 used_imports: FxHashSet<NodeId>,
946 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
947 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
949 /// Privacy errors are delayed until the end in order to deduplicate them.
950 privacy_errors: Vec<PrivacyError<'a>>,
951 /// Ambiguity errors are delayed for deduplication.
952 ambiguity_errors: Vec<AmbiguityError<'a>>,
953 /// `use` injections are delayed for better placement and deduplication.
954 use_injections: Vec<UseError<'a>>,
955 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
956 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
958 arenas: &'a ResolverArenas<'a>,
959 dummy_binding: &'a NameBinding<'a>,
961 crate_loader: CrateLoader<'a>,
962 macro_names: FxHashSet<Ident>,
963 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
964 registered_attrs: FxHashSet<Ident>,
965 registered_tools: FxHashSet<Ident>,
966 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
967 all_macros: FxHashMap<Symbol, Res>,
968 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
969 dummy_ext_bang: Lrc<SyntaxExtension>,
970 dummy_ext_derive: Lrc<SyntaxExtension>,
971 non_macro_attr: Lrc<SyntaxExtension>,
972 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
973 ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
974 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
975 proc_macro_stubs: FxHashSet<LocalDefId>,
976 /// Traces collected during macro resolution and validated when it's complete.
977 single_segment_macro_resolutions:
978 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
979 multi_segment_macro_resolutions:
980 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
981 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
982 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
983 /// Derive macros cannot modify the item themselves and have to store the markers in the global
984 /// context, so they attach the markers to derive container IDs using this resolver table.
985 containers_deriving_copy: FxHashSet<LocalExpnId>,
986 /// Parent scopes in which the macros were invoked.
987 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
988 invocation_parent_scopes: FxHashMap<LocalExpnId, ParentScope<'a>>,
989 /// `macro_rules` scopes *produced* by expanding the macro invocations,
990 /// include all the `macro_rules` items and other invocations generated by them.
991 output_macro_rules_scopes: FxHashMap<LocalExpnId, MacroRulesScopeRef<'a>>,
992 /// Helper attributes that are in scope for the given expansion.
993 helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
994 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
995 /// with the given `ExpnId`.
996 derive_data: FxHashMap<LocalExpnId, DeriveData>,
998 /// Avoid duplicated errors for "name already defined".
999 name_already_seen: FxHashMap<Symbol, Span>,
1001 potentially_unused_imports: Vec<&'a Import<'a>>,
1003 /// Table for mapping struct IDs into struct constructor IDs,
1004 /// it's not used during normal resolution, only for better error reporting.
1005 /// Also includes of list of each fields visibility
1006 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1008 /// Features enabled for this crate.
1009 active_features: FxHashSet<Symbol>,
1011 lint_buffer: LintBuffer,
1013 next_node_id: NodeId,
1015 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1016 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1018 /// Indices of unnamed struct or variant fields with unresolved attributes.
1019 placeholder_field_indices: FxHashMap<NodeId, usize>,
1020 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1021 /// we know what parent node that fragment should be attached to thanks to this table,
1022 /// and how the `impl Trait` fragments were introduced.
1023 invocation_parents: FxHashMap<LocalExpnId, (LocalDefId, ImplTraitContext)>,
1025 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1026 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1027 /// FIXME: Replace with a more general AST map (together with some other fields).
1028 trait_impl_items: FxHashSet<LocalDefId>,
1030 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1031 /// Amount of lifetime parameters for each item in the crate.
1032 item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
1034 main_def: Option<MainDefinition>,
1035 trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
1036 /// A list of proc macro LocalDefIds, written out in the order in which
1037 /// they are declared in the static array generated by proc_macro_harness.
1038 proc_macros: Vec<NodeId>,
1039 confused_type_with_std_module: FxHashMap<Span, Span>,
1042 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1044 pub struct ResolverArenas<'a> {
1045 modules: TypedArena<ModuleData<'a>>,
1046 local_modules: RefCell<Vec<Module<'a>>>,
1047 imports: TypedArena<Import<'a>>,
1048 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1049 ast_paths: TypedArena<ast::Path>,
1050 dropless: DroplessArena,
1053 impl<'a> ResolverArenas<'a> {
1054 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1055 let module = self.modules.alloc(module);
1056 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1057 self.local_modules.borrow_mut().push(module);
1061 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1062 self.local_modules.borrow()
1064 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1065 self.dropless.alloc(name_binding)
1067 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1068 self.imports.alloc(import)
1070 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1071 self.name_resolutions.alloc(Default::default())
1073 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1074 PtrKey(self.dropless.alloc(Cell::new(scope)))
1076 fn alloc_macro_rules_binding(
1078 binding: MacroRulesBinding<'a>,
1079 ) -> &'a MacroRulesBinding<'a> {
1080 self.dropless.alloc(binding)
1082 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1083 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1085 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1086 self.dropless.alloc_from_iter(spans)
1090 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1091 fn as_mut(&mut self) -> &mut Resolver<'a> {
1096 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1097 fn parent(self, id: DefId) -> Option<DefId> {
1098 match id.as_local() {
1099 Some(id) => self.definitions.def_key(id).parent,
1100 None => self.cstore().def_key(id).parent,
1102 .map(|index| DefId { index, ..id })
1106 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1107 /// the resolver is no longer needed as all the relevant information is inline.
1108 impl ResolverAstLowering for Resolver<'_> {
1109 fn def_key(&mut self, id: DefId) -> DefKey {
1110 if let Some(id) = id.as_local() {
1111 self.definitions().def_key(id)
1113 self.cstore().def_key(id)
1118 fn def_span(&self, id: LocalDefId) -> Span {
1119 self.definitions.def_span(id)
1122 fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
1123 if let Some(def_id) = def_id.as_local() {
1124 self.item_generics_num_lifetimes[&def_id]
1126 self.cstore().item_generics_num_lifetimes(def_id, self.session)
1130 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1131 self.legacy_const_generic_args(expr)
1134 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1135 self.partial_res_map.get(&id).cloned()
1138 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1139 self.import_res_map.get(&id).cloned().unwrap_or_default()
1142 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1143 self.label_res_map.get(&id).cloned()
1146 fn definitions(&mut self) -> &mut Definitions {
1147 &mut self.definitions
1150 fn lint_buffer(&mut self) -> &mut LintBuffer {
1151 &mut self.lint_buffer
1154 fn next_node_id(&mut self) -> NodeId {
1158 fn take_trait_map(&mut self) -> NodeMap<Vec<TraitCandidate>> {
1159 std::mem::replace(&mut self.trait_map, None).unwrap()
1162 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1163 self.node_id_to_def_id.get(&node).copied()
1166 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1167 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1170 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1171 match def_id.as_local() {
1172 Some(def_id) => self.definitions.def_path_hash(def_id),
1173 None => self.cstore().def_path_hash(def_id),
1177 /// Adds a definition with a parent definition.
1181 node_id: ast::NodeId,
1187 !self.node_id_to_def_id.contains_key(&node_id),
1188 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1191 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1194 // Find the next free disambiguator for this key.
1195 let next_disambiguator = &mut self.next_disambiguator;
1196 let next_disambiguator = |parent, data| {
1197 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1198 let disambiguator = *next_disamb;
1199 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1203 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator, span);
1205 // Some things for which we allocate `LocalDefId`s don't correspond to
1206 // anything in the AST, so they don't have a `NodeId`. For these cases
1207 // we don't need a mapping from `NodeId` to `LocalDefId`.
1208 if node_id != ast::DUMMY_NODE_ID {
1209 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1210 self.node_id_to_def_id.insert(node_id, def_id);
1212 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1218 struct ExpandHasher<'a, 'b> {
1219 source_map: CachingSourceMapView<'a>,
1220 resolver: &'a Resolver<'b>,
1223 impl<'a, 'b> rustc_span::HashStableContext for ExpandHasher<'a, 'b> {
1225 fn hash_spans(&self) -> bool {
1230 fn def_span(&self, id: LocalDefId) -> Span {
1231 self.resolver.def_span(id)
1235 fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
1236 self.resolver.def_path_hash(def_id)
1240 fn span_data_to_lines_and_cols(
1242 span: &rustc_span::SpanData,
1243 ) -> Option<(Lrc<rustc_span::SourceFile>, usize, rustc_span::BytePos, usize, rustc_span::BytePos)>
1245 self.source_map.span_data_to_lines_and_cols(span)
1249 impl<'a> Resolver<'a> {
1251 session: &'a Session,
1254 metadata_loader: Box<MetadataLoaderDyn>,
1255 arenas: &'a ResolverArenas<'a>,
1257 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1258 let root_def_id = root_local_def_id.to_def_id();
1259 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1260 let graph_root = arenas.alloc_module(ModuleData {
1261 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1262 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1264 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1265 let empty_module = arenas.alloc_module(ModuleData {
1266 no_implicit_prelude: true,
1275 let mut module_map = FxHashMap::default();
1276 module_map.insert(root_local_def_id, graph_root);
1278 let definitions = Definitions::new(session.local_stable_crate_id(), krate.span);
1279 let root = definitions.get_root_def();
1281 let mut visibilities = FxHashMap::default();
1282 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1284 let mut def_id_to_node_id = IndexVec::default();
1285 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1286 let mut node_id_to_def_id = FxHashMap::default();
1287 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1289 let mut invocation_parents = FxHashMap::default();
1290 invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
1292 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1296 .filter(|(_, entry)| entry.add_prelude)
1297 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1300 if !session.contains_name(&krate.attrs, sym::no_core) {
1301 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1302 if !session.contains_name(&krate.attrs, sym::no_std) {
1303 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1307 let (registered_attrs, registered_tools) =
1308 macros::registered_attrs_and_tools(session, &krate.attrs);
1310 let features = session.features_untracked();
1312 let mut resolver = Resolver {
1317 // The outermost module has def ID 0; this is not reflected in the
1323 has_self: FxHashSet::default(),
1324 field_names: FxHashMap::default(),
1326 determined_imports: Vec::new(),
1327 indeterminate_imports: Vec::new(),
1329 last_import_segment: false,
1330 unusable_binding: None,
1332 pat_span_map: Default::default(),
1333 partial_res_map: Default::default(),
1334 import_res_map: Default::default(),
1335 label_res_map: Default::default(),
1336 extern_crate_map: Default::default(),
1337 export_map: FxHashMap::default(),
1338 trait_map: Some(NodeMap::default()),
1339 underscore_disambiguator: 0,
1342 block_map: Default::default(),
1343 extern_module_map: FxHashMap::default(),
1344 binding_parent_modules: FxHashMap::default(),
1345 ast_transform_scopes: FxHashMap::default(),
1347 glob_map: Default::default(),
1349 used_imports: FxHashSet::default(),
1350 maybe_unused_trait_imports: Default::default(),
1351 maybe_unused_extern_crates: Vec::new(),
1353 privacy_errors: Vec::new(),
1354 ambiguity_errors: Vec::new(),
1355 use_injections: Vec::new(),
1356 macro_expanded_macro_export_errors: BTreeSet::new(),
1359 dummy_binding: arenas.alloc_name_binding(NameBinding {
1360 kind: NameBindingKind::Res(Res::Err, false),
1362 expansion: LocalExpnId::ROOT,
1364 vis: ty::Visibility::Public,
1367 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1368 macro_names: FxHashSet::default(),
1369 builtin_macros: Default::default(),
1372 macro_use_prelude: FxHashMap::default(),
1373 all_macros: FxHashMap::default(),
1374 macro_map: FxHashMap::default(),
1375 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1376 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1377 non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.edition())),
1378 invocation_parent_scopes: Default::default(),
1379 output_macro_rules_scopes: Default::default(),
1380 helper_attrs: Default::default(),
1381 derive_data: Default::default(),
1382 local_macro_def_scopes: FxHashMap::default(),
1383 name_already_seen: FxHashMap::default(),
1384 potentially_unused_imports: Vec::new(),
1385 struct_constructors: Default::default(),
1386 unused_macros: Default::default(),
1387 proc_macro_stubs: Default::default(),
1388 single_segment_macro_resolutions: Default::default(),
1389 multi_segment_macro_resolutions: Default::default(),
1390 builtin_attrs: Default::default(),
1391 containers_deriving_copy: Default::default(),
1392 active_features: features
1393 .declared_lib_features
1395 .map(|(feat, ..)| *feat)
1396 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1398 lint_buffer: LintBuffer::default(),
1399 next_node_id: NodeId::from_u32(1),
1402 placeholder_field_indices: Default::default(),
1404 next_disambiguator: Default::default(),
1405 trait_impl_items: Default::default(),
1406 legacy_const_generic_args: Default::default(),
1407 item_generics_num_lifetimes: Default::default(),
1408 main_def: Default::default(),
1409 trait_impls: Default::default(),
1410 proc_macros: Default::default(),
1411 confused_type_with_std_module: Default::default(),
1414 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1415 resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope);
1420 fn create_stable_hashing_context(&self) -> ExpandHasher<'_, 'a> {
1422 source_map: CachingSourceMapView::new(self.session.source_map()),
1427 pub fn next_node_id(&mut self) -> NodeId {
1432 .expect("input too large; ran out of NodeIds");
1433 self.next_node_id = ast::NodeId::from_usize(next);
1437 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1438 &mut self.lint_buffer
1441 pub fn arenas() -> ResolverArenas<'a> {
1445 pub fn into_outputs(self) -> ResolverOutputs {
1446 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1447 let definitions = self.definitions;
1448 let visibilities = self.visibilities;
1449 let extern_crate_map = self.extern_crate_map;
1450 let export_map = self.export_map;
1451 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1452 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1453 let glob_map = self.glob_map;
1454 let main_def = self.main_def;
1455 let confused_type_with_std_module = self.confused_type_with_std_module;
1458 cstore: Box::new(self.crate_loader.into_cstore()),
1463 maybe_unused_trait_imports,
1464 maybe_unused_extern_crates,
1465 extern_prelude: self
1468 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1471 trait_impls: self.trait_impls,
1473 confused_type_with_std_module,
1477 pub fn clone_outputs(&self) -> ResolverOutputs {
1478 let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
1480 definitions: self.definitions.clone(),
1481 cstore: Box::new(self.cstore().clone()),
1482 visibilities: self.visibilities.clone(),
1483 extern_crate_map: self.extern_crate_map.clone(),
1484 export_map: self.export_map.clone(),
1485 glob_map: self.glob_map.clone(),
1486 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1487 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1488 extern_prelude: self
1491 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1493 main_def: self.main_def,
1494 trait_impls: self.trait_impls.clone(),
1496 confused_type_with_std_module: self.confused_type_with_std_module.clone(),
1500 pub fn cstore(&self) -> &CStore {
1501 self.crate_loader.cstore()
1504 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1506 MacroKind::Bang => self.dummy_ext_bang.clone(),
1507 MacroKind::Derive => self.dummy_ext_derive.clone(),
1508 MacroKind::Attr => self.non_macro_attr.clone(),
1512 /// Runs the function on each namespace.
1513 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1519 fn is_builtin_macro(&mut self, res: Res) -> bool {
1520 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1523 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1525 match ctxt.outer_expn_data().macro_def_id {
1526 Some(def_id) => return def_id,
1527 None => ctxt.remove_mark(),
1532 /// Entry point to crate resolution.
1533 pub fn resolve_crate(&mut self, krate: &Crate) {
1534 self.session.time("resolve_crate", || {
1535 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1536 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1537 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1538 self.session.time("resolve_main", || self.resolve_main());
1539 self.session.time("resolve_check_unused", || self.check_unused(krate));
1540 self.session.time("resolve_report_errors", || self.report_errors(krate));
1541 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1545 pub fn traits_in_scope(
1547 current_trait: Option<Module<'a>>,
1548 parent_scope: &ParentScope<'a>,
1549 ctxt: SyntaxContext,
1550 assoc_item: Option<(Symbol, Namespace)>,
1551 ) -> Vec<TraitCandidate> {
1552 let mut found_traits = Vec::new();
1554 if let Some(module) = current_trait {
1555 if self.trait_may_have_item(Some(module), assoc_item) {
1556 let def_id = module.def_id().unwrap();
1557 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1561 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1563 Scope::Module(module, _) => {
1564 this.traits_in_module(module, assoc_item, &mut found_traits);
1566 Scope::StdLibPrelude => {
1567 if let Some(module) = this.prelude {
1568 this.traits_in_module(module, assoc_item, &mut found_traits);
1571 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1572 _ => unreachable!(),
1580 fn traits_in_module(
1583 assoc_item: Option<(Symbol, Namespace)>,
1584 found_traits: &mut Vec<TraitCandidate>,
1586 module.ensure_traits(self);
1587 let traits = module.traits.borrow();
1588 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1589 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1590 let def_id = trait_binding.res().def_id();
1591 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1592 found_traits.push(TraitCandidate { def_id, import_ids });
1597 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1598 // associated item with the given name and namespace (if specified). This is a conservative
1599 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1600 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1601 // associated items.
1602 fn trait_may_have_item(
1604 trait_module: Option<Module<'a>>,
1605 assoc_item: Option<(Symbol, Namespace)>,
1607 match (trait_module, assoc_item) {
1608 (Some(trait_module), Some((name, ns))) => {
1609 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1610 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1611 assoc_ns == ns && assoc_ident.name == name
1618 fn find_transitive_imports(
1620 mut kind: &NameBindingKind<'_>,
1622 ) -> SmallVec<[LocalDefId; 1]> {
1623 let mut import_ids = smallvec![];
1624 while let NameBindingKind::Import { import, binding, .. } = kind {
1625 let id = self.local_def_id(import.id);
1626 self.maybe_unused_trait_imports.insert(id);
1627 self.add_to_glob_map(&import, trait_name);
1628 import_ids.push(id);
1629 kind = &binding.kind;
1638 nearest_parent_mod: DefId,
1642 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1643 self.arenas.alloc_module(module)
1646 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1647 let ident = ident.normalize_to_macros_2_0();
1648 let disambiguator = if ident.name == kw::Underscore {
1649 self.underscore_disambiguator += 1;
1650 self.underscore_disambiguator
1654 BindingKey { ident, ns, disambiguator }
1657 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1658 if module.populate_on_access.get() {
1659 module.populate_on_access.set(false);
1660 self.build_reduced_graph_external(module);
1662 &module.lazy_resolutions
1669 ) -> &'a RefCell<NameResolution<'a>> {
1671 .resolutions(module)
1674 .or_insert_with(|| self.arenas.alloc_name_resolution())
1680 used_binding: &'a NameBinding<'a>,
1681 is_lexical_scope: bool,
1683 if let Some((b2, kind)) = used_binding.ambiguity {
1684 self.ambiguity_errors.push(AmbiguityError {
1689 misc1: AmbiguityErrorMisc::None,
1690 misc2: AmbiguityErrorMisc::None,
1693 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1694 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1695 // but not introduce it, as used if they are accessed from lexical scope.
1696 if is_lexical_scope {
1697 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1698 if let Some(crate_item) = entry.extern_crate_item {
1699 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1706 import.used.set(true);
1707 self.used_imports.insert(import.id);
1708 self.add_to_glob_map(&import, ident);
1709 self.record_use(ident, binding, false);
1714 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1715 if import.is_glob() {
1716 let def_id = self.local_def_id(import.id);
1717 self.glob_map.entry(def_id).or_default().insert(ident.name);
1721 /// A generic scope visitor.
1722 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1723 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1726 scope_set: ScopeSet<'a>,
1727 parent_scope: &ParentScope<'a>,
1728 ctxt: SyntaxContext,
1729 mut visitor: impl FnMut(
1732 /*use_prelude*/ bool,
1736 // General principles:
1737 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1738 // built into the language or standard library. This way we can add new names into the
1739 // language or standard library without breaking user code.
1740 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1741 // Places to search (in order of decreasing priority):
1743 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1744 // (open set, not controlled).
1745 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1746 // (open, not controlled).
1747 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1748 // 4. Tool modules (closed, controlled right now, but not in the future).
1749 // 5. Standard library prelude (de-facto closed, controlled).
1750 // 6. Language prelude (closed, controlled).
1752 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1753 // (open set, not controlled).
1754 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1755 // (open, not controlled).
1756 // 3. Standard library prelude (de-facto closed, controlled).
1758 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1759 // are currently reported as errors. They should be higher in priority than preludes
1760 // and probably even names in modules according to the "general principles" above. They
1761 // also should be subject to restricted shadowing because are effectively produced by
1762 // derives (you need to resolve the derive first to add helpers into scope), but they
1763 // should be available before the derive is expanded for compatibility.
1764 // It's mess in general, so we are being conservative for now.
1765 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1766 // priority than prelude macros, but create ambiguities with macros in modules.
1767 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1768 // (open, not controlled). Have higher priority than prelude macros, but create
1769 // ambiguities with `macro_rules`.
1770 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1771 // 4a. User-defined prelude from macro-use
1772 // (open, the open part is from macro expansions, not controlled).
1773 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1774 // 4c. Standard library prelude (de-facto closed, controlled).
1775 // 6. Language prelude: builtin attributes (closed, controlled).
1777 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1778 let (ns, macro_kind, is_absolute_path) = match scope_set {
1779 ScopeSet::All(ns, _) => (ns, None, false),
1780 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1781 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1782 ScopeSet::Late(ns, ..) => (ns, None, false),
1784 let module = match scope_set {
1785 // Start with the specified module.
1786 ScopeSet::Late(_, module, _) => module,
1787 // Jump out of trait or enum modules, they do not act as scopes.
1788 _ => parent_scope.module.nearest_item_scope(),
1790 let mut scope = match ns {
1791 _ if is_absolute_path => Scope::CrateRoot,
1792 TypeNS | ValueNS => Scope::Module(module, None),
1793 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1795 let mut ctxt = ctxt.normalize_to_macros_2_0();
1796 let mut use_prelude = !module.no_implicit_prelude;
1799 let visit = match scope {
1800 // Derive helpers are not in scope when resolving derives in the same container.
1801 Scope::DeriveHelpers(expn_id) => {
1802 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1804 Scope::DeriveHelpersCompat => true,
1805 Scope::MacroRules(macro_rules_scope) => {
1806 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1807 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1808 // As another consequence of this optimization visitors never observe invocation
1809 // scopes for macros that were already expanded.
1810 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1811 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1812 macro_rules_scope.set(next_scope.get());
1819 Scope::CrateRoot => true,
1820 Scope::Module(..) => true,
1821 Scope::RegisteredAttrs => use_prelude,
1822 Scope::MacroUsePrelude => use_prelude || rust_2015,
1823 Scope::BuiltinAttrs => true,
1824 Scope::ExternPrelude => use_prelude || is_absolute_path,
1825 Scope::ToolPrelude => use_prelude,
1826 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1827 Scope::BuiltinTypes => true,
1831 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1832 return break_result;
1836 scope = match scope {
1837 Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
1838 Scope::DeriveHelpers(expn_id) => {
1839 // Derive helpers are not visible to code generated by bang or derive macros.
1840 let expn_data = expn_id.expn_data();
1841 match expn_data.kind {
1843 | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
1844 Scope::DeriveHelpersCompat
1846 _ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
1849 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1850 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1851 MacroRulesScope::Binding(binding) => {
1852 Scope::MacroRules(binding.parent_macro_rules_scope)
1854 MacroRulesScope::Invocation(invoc_id) => {
1855 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1857 MacroRulesScope::Empty => Scope::Module(module, None),
1859 Scope::CrateRoot => match ns {
1861 ctxt.adjust(ExpnId::root());
1862 Scope::ExternPrelude
1864 ValueNS | MacroNS => break,
1866 Scope::Module(module, prev_lint_id) => {
1867 use_prelude = !module.no_implicit_prelude;
1868 let derive_fallback_lint_id = match scope_set {
1869 ScopeSet::Late(.., lint_id) => lint_id,
1872 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1873 Some((parent_module, lint_id)) => {
1874 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1877 ctxt.adjust(ExpnId::root());
1879 TypeNS => Scope::ExternPrelude,
1880 ValueNS => Scope::StdLibPrelude,
1881 MacroNS => Scope::RegisteredAttrs,
1886 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1887 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1888 Scope::BuiltinAttrs => break, // nowhere else to search
1889 Scope::ExternPrelude if is_absolute_path => break,
1890 Scope::ExternPrelude => Scope::ToolPrelude,
1891 Scope::ToolPrelude => Scope::StdLibPrelude,
1892 Scope::StdLibPrelude => match ns {
1893 TypeNS => Scope::BuiltinTypes,
1894 ValueNS => break, // nowhere else to search
1895 MacroNS => Scope::BuiltinAttrs,
1897 Scope::BuiltinTypes => break, // nowhere else to search
1904 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1905 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1906 /// `ident` in the first scope that defines it (or None if no scopes define it).
1908 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1909 /// the items are defined in the block. For example,
1912 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1915 /// g(); // This resolves to the local variable `g` since it shadows the item.
1919 /// Invariant: This must only be called during main resolution, not during
1920 /// import resolution.
1921 fn resolve_ident_in_lexical_scope(
1925 parent_scope: &ParentScope<'a>,
1926 record_used_id: Option<NodeId>,
1929 ) -> Option<LexicalScopeBinding<'a>> {
1930 assert!(ns == TypeNS || ns == ValueNS);
1931 let orig_ident = ident;
1932 if ident.name == kw::Empty {
1933 return Some(LexicalScopeBinding::Res(Res::Err));
1935 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1936 // FIXME(jseyfried) improve `Self` hygiene
1937 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1938 (empty_span, empty_span)
1939 } else if ns == TypeNS {
1940 let normalized_span = ident.span.normalize_to_macros_2_0();
1941 (normalized_span, normalized_span)
1943 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1945 ident.span = general_span;
1946 let normalized_ident = Ident { span: normalized_span, ..ident };
1948 // Walk backwards up the ribs in scope.
1949 let record_used = record_used_id.is_some();
1950 let mut module = self.graph_root;
1951 for i in (0..ribs.len()).rev() {
1952 debug!("walk rib\n{:?}", ribs[i].bindings);
1953 // Use the rib kind to determine whether we are resolving parameters
1954 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1955 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1956 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1958 // The ident resolves to a type parameter or local variable.
1959 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1965 *original_rib_ident_def,
1970 module = match ribs[i].kind {
1971 ModuleRibKind(module) => module,
1972 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1973 // If an invocation of this macro created `ident`, give up on `ident`
1974 // and switch to `ident`'s source from the macro definition.
1975 ident.span.remove_mark();
1982 ModuleKind::Block(..) => {} // We can see through blocks
1986 let item = self.resolve_ident_in_module_unadjusted(
1987 ModuleOrUniformRoot::Module(module),
1994 if let Ok(binding) = item {
1995 // The ident resolves to an item.
1996 return Some(LexicalScopeBinding::Item(binding));
1999 self.early_resolve_ident_in_lexical_scope(
2001 ScopeSet::Late(ns, module, record_used_id),
2008 .map(LexicalScopeBinding::Item)
2011 fn hygienic_lexical_parent(
2014 ctxt: &mut SyntaxContext,
2015 derive_fallback_lint_id: Option<NodeId>,
2016 ) -> Option<(Module<'a>, Option<NodeId>)> {
2017 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
2018 return Some((self.macro_def_scope(ctxt.remove_mark()), None));
2021 if let ModuleKind::Block(..) = module.kind {
2022 return Some((module.parent.unwrap().nearest_item_scope(), None));
2025 // We need to support the next case under a deprecation warning
2028 // ---- begin: this comes from a proc macro derive
2029 // mod implementation_details {
2030 // // Note that `MyStruct` is not in scope here.
2031 // impl SomeTrait for MyStruct { ... }
2035 // So we have to fall back to the module's parent during lexical resolution in this case.
2036 if derive_fallback_lint_id.is_some() {
2037 if let Some(parent) = module.parent {
2038 // Inner module is inside the macro, parent module is outside of the macro.
2039 if module.expansion != parent.expansion
2040 && module.expansion.is_descendant_of(parent.expansion)
2042 // The macro is a proc macro derive
2043 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
2044 let ext = self.get_macro_by_def_id(def_id);
2045 if ext.builtin_name.is_none()
2046 && ext.macro_kind() == MacroKind::Derive
2047 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
2049 return Some((parent, derive_fallback_lint_id));
2059 fn resolve_ident_in_module(
2061 module: ModuleOrUniformRoot<'a>,
2064 parent_scope: &ParentScope<'a>,
2067 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2068 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2069 .map_err(|(determinacy, _)| determinacy)
2072 fn resolve_ident_in_module_ext(
2074 module: ModuleOrUniformRoot<'a>,
2077 parent_scope: &ParentScope<'a>,
2080 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2081 let tmp_parent_scope;
2082 let mut adjusted_parent_scope = parent_scope;
2084 ModuleOrUniformRoot::Module(m) => {
2085 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2087 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2088 adjusted_parent_scope = &tmp_parent_scope;
2091 ModuleOrUniformRoot::ExternPrelude => {
2092 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2094 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2098 self.resolve_ident_in_module_unadjusted_ext(
2102 adjusted_parent_scope,
2109 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2110 debug!("resolve_crate_root({:?})", ident);
2111 let mut ctxt = ident.span.ctxt();
2112 let mark = if ident.name == kw::DollarCrate {
2113 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2114 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2115 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2116 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2117 // definitions actually produced by `macro` and `macro` definitions produced by
2118 // `macro_rules!`, but at least such configurations are not stable yet.
2119 ctxt = ctxt.normalize_to_macro_rules();
2121 "resolve_crate_root: marks={:?}",
2122 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2124 let mut iter = ctxt.marks().into_iter().rev().peekable();
2125 let mut result = None;
2126 // Find the last opaque mark from the end if it exists.
2127 while let Some(&(mark, transparency)) = iter.peek() {
2128 if transparency == Transparency::Opaque {
2129 result = Some(mark);
2136 "resolve_crate_root: found opaque mark {:?} {:?}",
2138 result.map(|r| r.expn_data())
2140 // Then find the last semi-transparent mark from the end if it exists.
2141 for (mark, transparency) in iter {
2142 if transparency == Transparency::SemiTransparent {
2143 result = Some(mark);
2149 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2151 result.map(|r| r.expn_data())
2155 debug!("resolve_crate_root: not DollarCrate");
2156 ctxt = ctxt.normalize_to_macros_2_0();
2157 ctxt.adjust(ExpnId::root())
2159 let module = match mark {
2160 Some(def) => self.macro_def_scope(def),
2163 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2166 return self.graph_root;
2169 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2171 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2180 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2181 let mut module = self.get_module(module.nearest_parent_mod);
2182 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2183 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2184 module = self.get_module(parent.nearest_parent_mod);
2192 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2193 parent_scope: &ParentScope<'a>,
2196 crate_lint: CrateLint,
2197 ) -> PathResult<'a> {
2198 self.resolve_path_with_ribs(
2209 fn resolve_path_with_ribs(
2212 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2213 parent_scope: &ParentScope<'a>,
2216 crate_lint: CrateLint,
2217 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2218 ) -> PathResult<'a> {
2219 let mut module = None;
2220 let mut allow_super = true;
2221 let mut second_binding = None;
2224 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2225 path_span={:?}, crate_lint={:?})",
2226 path, opt_ns, record_used, path_span, crate_lint,
2229 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2230 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2231 let record_segment_res = |this: &mut Self, res| {
2233 if let Some(id) = id {
2234 if !this.partial_res_map.contains_key(&id) {
2235 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2236 this.record_partial_res(id, PartialRes::new(res));
2242 let is_last = i == path.len() - 1;
2243 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2244 let name = ident.name;
2246 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2249 if allow_super && name == kw::Super {
2250 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2251 let self_module = match i {
2252 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2254 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2258 if let Some(self_module) = self_module {
2259 if let Some(parent) = self_module.parent {
2260 module = Some(ModuleOrUniformRoot::Module(
2261 self.resolve_self(&mut ctxt, parent),
2266 let msg = "there are too many leading `super` keywords".to_string();
2267 return PathResult::Failed {
2271 is_error_from_last_segment: false,
2275 if name == kw::SelfLower {
2276 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2277 module = Some(ModuleOrUniformRoot::Module(
2278 self.resolve_self(&mut ctxt, parent_scope.module),
2282 if name == kw::PathRoot && ident.span.rust_2018() {
2283 module = Some(ModuleOrUniformRoot::ExternPrelude);
2286 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2287 // `::a::b` from 2015 macro on 2018 global edition
2288 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2291 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2292 // `::a::b`, `crate::a::b` or `$crate::a::b`
2293 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2299 // Report special messages for path segment keywords in wrong positions.
2300 if ident.is_path_segment_keyword() && i != 0 {
2301 let name_str = if name == kw::PathRoot {
2302 "crate root".to_string()
2304 format!("`{}`", name)
2306 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2307 format!("global paths cannot start with {}", name_str)
2309 format!("{} in paths can only be used in start position", name_str)
2311 return PathResult::Failed {
2315 is_error_from_last_segment: false,
2319 enum FindBindingResult<'a> {
2320 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2321 PathResult(PathResult<'a>),
2323 let find_binding_in_ns = |this: &mut Self, ns| {
2324 let binding = if let Some(module) = module {
2325 this.resolve_ident_in_module(
2333 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2334 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2335 this.early_resolve_ident_in_lexical_scope(
2344 let record_used_id = if record_used {
2345 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2349 match this.resolve_ident_in_lexical_scope(
2357 // we found a locally-imported or available item/module
2358 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2359 // we found a local variable or type param
2360 Some(LexicalScopeBinding::Res(res))
2361 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2363 record_segment_res(this, res);
2364 return FindBindingResult::PathResult(PathResult::NonModule(
2365 PartialRes::with_unresolved_segments(res, path.len() - 1),
2368 _ => Err(Determinacy::determined(record_used)),
2371 FindBindingResult::Binding(binding)
2373 let binding = match find_binding_in_ns(self, ns) {
2374 FindBindingResult::PathResult(x) => return x,
2375 FindBindingResult::Binding(binding) => binding,
2380 second_binding = Some(binding);
2382 let res = binding.res();
2383 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2384 if let Some(next_module) = binding.module() {
2385 module = Some(ModuleOrUniformRoot::Module(next_module));
2386 record_segment_res(self, res);
2387 } else if res == Res::ToolMod && i + 1 != path.len() {
2388 if binding.is_import() {
2392 "cannot use a tool module through an import",
2394 .span_note(binding.span, "the tool module imported here")
2397 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2398 return PathResult::NonModule(PartialRes::new(res));
2399 } else if res == Res::Err {
2400 return PathResult::NonModule(PartialRes::new(Res::Err));
2401 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2402 self.lint_if_path_starts_with_module(
2408 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2413 let label = format!(
2414 "`{}` is {} {}, not a module",
2420 return PathResult::Failed {
2424 is_error_from_last_segment: is_last,
2428 Err(Undetermined) => return PathResult::Indeterminate,
2429 Err(Determined) => {
2430 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2431 if opt_ns.is_some() && !module.is_normal() {
2432 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2433 module.res().unwrap(),
2438 let module_res = match module {
2439 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2442 let (label, suggestion) = if module_res == self.graph_root.res() {
2443 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2444 // Don't look up import candidates if this is a speculative resolve
2445 let mut candidates = if record_used {
2446 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2450 candidates.sort_by_cached_key(|c| {
2451 (c.path.segments.len(), pprust::path_to_string(&c.path))
2453 if let Some(candidate) = candidates.get(0) {
2455 String::from("unresolved import"),
2457 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2458 String::from("a similar path exists"),
2459 Applicability::MaybeIncorrect,
2462 } else if self.session.edition() == Edition::Edition2015 {
2463 (format!("maybe a missing crate `{}`?", ident), None)
2465 (format!("could not find `{}` in the crate root", ident), None)
2473 .map_or(false, |c| c.is_ascii_uppercase())
2475 // Check whether the name refers to an item in the value namespace.
2476 let suggestion = if ribs.is_some() {
2477 let match_span = match self.resolve_ident_in_lexical_scope(
2483 &ribs.unwrap()[ValueNS],
2485 // Name matches a local variable. For example:
2488 // let Foo: &str = "";
2489 // println!("{}", Foo::Bar); // Name refers to local
2490 // // variable `Foo`.
2493 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2494 Some(*self.pat_span_map.get(&id).unwrap())
2497 // Name matches item from a local name binding
2498 // created by `use` declaration. For example:
2500 // pub Foo: &str = "";
2504 // println!("{}", Foo::Bar); // Name refers to local
2505 // // binding `Foo`.
2508 Some(LexicalScopeBinding::Item(name_binding)) => {
2509 Some(name_binding.span)
2514 if let Some(span) = match_span {
2516 vec![(span, String::from(""))],
2517 format!("`{}` is defined here, but is not a type", ident),
2518 Applicability::MaybeIncorrect,
2527 (format!("use of undeclared type `{}`", ident), suggestion)
2529 (format!("use of undeclared crate or module `{}`", ident), None)
2532 let parent = path[i - 1].ident.name;
2533 let parent = match parent {
2534 // ::foo is mounted at the crate root for 2015, and is the extern
2535 // prelude for 2018+
2536 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2537 "the list of imported crates".to_owned()
2539 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2541 format!("`{}`", parent)
2545 let mut msg = format!("could not find `{}` in {}", ident, parent);
2546 if ns == TypeNS || ns == ValueNS {
2547 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2548 if let FindBindingResult::Binding(Ok(binding)) =
2549 find_binding_in_ns(self, ns_to_try)
2551 let mut found = |what| {
2553 "expected {}, found {} `{}` in {}",
2560 if binding.module().is_some() {
2563 match binding.res() {
2564 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2565 _ => found(ns_to_try.descr()),
2572 return PathResult::Failed {
2576 is_error_from_last_segment: is_last,
2582 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2584 PathResult::Module(match module {
2585 Some(module) => module,
2586 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2587 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2591 fn lint_if_path_starts_with_module(
2593 crate_lint: CrateLint,
2596 second_binding: Option<&NameBinding<'_>>,
2598 let (diag_id, diag_span) = match crate_lint {
2599 CrateLint::No => return,
2600 CrateLint::SimplePath(id) => (id, path_span),
2601 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2602 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2605 let first_name = match path.get(0) {
2606 // In the 2018 edition this lint is a hard error, so nothing to do
2607 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2611 // We're only interested in `use` paths which should start with
2612 // `{{root}}` currently.
2613 if first_name != kw::PathRoot {
2618 // If this import looks like `crate::...` it's already good
2619 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2620 // Otherwise go below to see if it's an extern crate
2622 // If the path has length one (and it's `PathRoot` most likely)
2623 // then we don't know whether we're gonna be importing a crate or an
2624 // item in our crate. Defer this lint to elsewhere
2628 // If the first element of our path was actually resolved to an
2629 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2630 // warning, this looks all good!
2631 if let Some(binding) = second_binding {
2632 if let NameBindingKind::Import { import, .. } = binding.kind {
2633 // Careful: we still want to rewrite paths from renamed extern crates.
2634 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2640 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2641 self.lint_buffer.buffer_lint_with_diagnostic(
2642 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2645 "absolute paths must start with `self`, `super`, \
2646 `crate`, or an external crate name in the 2018 edition",
2651 // Validate a local resolution (from ribs).
2652 fn validate_res_from_ribs(
2659 original_rib_ident_def: Ident,
2660 all_ribs: &[Rib<'a>],
2662 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2663 debug!("validate_res_from_ribs({:?})", res);
2664 let ribs = &all_ribs[rib_index + 1..];
2666 // An invalid forward use of a generic parameter from a previous default.
2667 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2669 let res_error = if rib_ident.name == kw::SelfUpper {
2670 ResolutionError::SelfInGenericParamDefault
2672 ResolutionError::ForwardDeclaredGenericParam
2674 self.report_error(span, res_error);
2676 assert_eq!(res, Res::Err);
2682 use ResolutionError::*;
2683 let mut res_err = None;
2688 | ClosureOrAsyncRibKind
2690 | MacroDefinition(..)
2691 | ForwardGenericParamBanRibKind => {
2692 // Nothing to do. Continue.
2694 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2695 // This was an attempt to access an upvar inside a
2696 // named function item. This is not allowed, so we
2699 // We don't immediately trigger a resolve error, because
2700 // we want certain other resolution errors (namely those
2701 // emitted for `ConstantItemRibKind` below) to take
2703 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2706 ConstantItemRibKind(_, item) => {
2707 // Still doesn't deal with upvars
2709 let (span, resolution_error) =
2710 if let Some((ident, constant_item_kind)) = item {
2711 let kind_str = match constant_item_kind {
2712 ConstantItemKind::Const => "const",
2713 ConstantItemKind::Static => "static",
2717 AttemptToUseNonConstantValueInConstant(
2718 ident, "let", kind_str,
2724 AttemptToUseNonConstantValueInConstant(
2725 original_rib_ident_def,
2731 self.report_error(span, resolution_error);
2735 ConstParamTyRibKind => {
2737 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2743 if let Some(res_err) = res_err {
2744 self.report_error(span, res_err);
2748 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2750 let has_generic_params: HasGenericParams = match rib.kind {
2752 | ClosureOrAsyncRibKind
2755 | MacroDefinition(..)
2756 | ForwardGenericParamBanRibKind => {
2757 // Nothing to do. Continue.
2761 ConstantItemRibKind(trivial, _) => {
2762 let features = self.session.features_untracked();
2763 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2764 if !(trivial || features.generic_const_exprs) {
2765 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2766 // we can't easily tell if it's generic at this stage, so we instead remember
2767 // this and then enforce the self type to be concrete later on.
2768 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2769 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2774 ResolutionError::ParamInNonTrivialAnonConst {
2775 name: rib_ident.name,
2781 self.session.delay_span_bug(span, CG_BUG_STR);
2789 // This was an attempt to use a type parameter outside its scope.
2790 ItemRibKind(has_generic_params) => has_generic_params,
2791 FnItemRibKind => HasGenericParams::Yes,
2792 ConstParamTyRibKind => {
2796 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2806 ResolutionError::GenericParamsFromOuterFunction(
2815 Res::Def(DefKind::ConstParam, _) => {
2816 let mut ribs = ribs.iter().peekable();
2817 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2818 // When declaring const parameters inside function signatures, the first rib
2819 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2820 // (spuriously) conflicting with the const param.
2825 let has_generic_params = match rib.kind {
2827 | ClosureOrAsyncRibKind
2830 | MacroDefinition(..)
2831 | ForwardGenericParamBanRibKind => continue,
2833 ConstantItemRibKind(trivial, _) => {
2834 let features = self.session.features_untracked();
2835 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2836 if !(trivial || features.generic_const_exprs) {
2840 ResolutionError::ParamInNonTrivialAnonConst {
2841 name: rib_ident.name,
2847 self.session.delay_span_bug(span, CG_BUG_STR);
2854 ItemRibKind(has_generic_params) => has_generic_params,
2855 FnItemRibKind => HasGenericParams::Yes,
2856 ConstParamTyRibKind => {
2860 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2867 // This was an attempt to use a const parameter outside its scope.
2871 ResolutionError::GenericParamsFromOuterFunction(
2885 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2886 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2887 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2888 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2892 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2893 debug!("(recording pat) recording {:?} for {:?}", node, span);
2894 self.pat_span_map.insert(node, span);
2897 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2898 vis.is_accessible_from(module.nearest_parent_mod, self)
2901 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2902 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2903 if !ptr::eq(module, old_module) {
2904 span_bug!(binding.span, "parent module is reset for binding");
2909 fn disambiguate_macro_rules_vs_modularized(
2911 macro_rules: &'a NameBinding<'a>,
2912 modularized: &'a NameBinding<'a>,
2914 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2915 // is disambiguated to mitigate regressions from macro modularization.
2916 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2918 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2919 self.binding_parent_modules.get(&PtrKey(modularized)),
2921 (Some(macro_rules), Some(modularized)) => {
2922 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2923 && modularized.is_ancestor_of(macro_rules)
2929 fn report_errors(&mut self, krate: &Crate) {
2930 self.report_with_use_injections(krate);
2932 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2933 let msg = "macro-expanded `macro_export` macros from the current crate \
2934 cannot be referred to by absolute paths";
2935 self.lint_buffer.buffer_lint_with_diagnostic(
2936 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2940 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2944 for ambiguity_error in &self.ambiguity_errors {
2945 self.report_ambiguity_error(ambiguity_error);
2948 let mut reported_spans = FxHashSet::default();
2949 for error in &self.privacy_errors {
2950 if reported_spans.insert(error.dedup_span) {
2951 self.report_privacy_error(error);
2956 fn report_with_use_injections(&mut self, krate: &Crate) {
2957 for UseError { mut err, candidates, def_id, instead, suggestion } in
2958 self.use_injections.drain(..)
2960 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2961 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2965 if !candidates.is_empty() {
2966 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2967 } else if let Some((span, msg, sugg, appl)) = suggestion {
2968 err.span_suggestion(span, msg, sugg, appl);
2974 fn report_conflict<'b>(
2979 new_binding: &NameBinding<'b>,
2980 old_binding: &NameBinding<'b>,
2982 // Error on the second of two conflicting names
2983 if old_binding.span.lo() > new_binding.span.lo() {
2984 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2987 let container = match parent.kind {
2988 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2989 ModuleKind::Block(..) => "block",
2992 let old_noun = match old_binding.is_import() {
2994 false => "definition",
2997 let new_participle = match new_binding.is_import() {
3003 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
3005 if let Some(s) = self.name_already_seen.get(&name) {
3011 let old_kind = match (ns, old_binding.module()) {
3012 (ValueNS, _) => "value",
3013 (MacroNS, _) => "macro",
3014 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
3015 (TypeNS, Some(module)) if module.is_normal() => "module",
3016 (TypeNS, Some(module)) if module.is_trait() => "trait",
3017 (TypeNS, _) => "type",
3020 let msg = format!("the name `{}` is defined multiple times", name);
3022 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
3023 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
3024 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
3025 true => struct_span_err!(self.session, span, E0254, "{}", msg),
3026 false => struct_span_err!(self.session, span, E0260, "{}", msg),
3028 _ => match (old_binding.is_import(), new_binding.is_import()) {
3029 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
3030 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
3031 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
3036 "`{}` must be defined only once in the {} namespace of this {}",
3042 err.span_label(span, format!("`{}` re{} here", name, new_participle));
3044 self.session.source_map().guess_head_span(old_binding.span),
3045 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
3048 // See https://github.com/rust-lang/rust/issues/32354
3049 use NameBindingKind::Import;
3050 let import = match (&new_binding.kind, &old_binding.kind) {
3051 // If there are two imports where one or both have attributes then prefer removing the
3052 // import without attributes.
3053 (Import { import: new, .. }, Import { import: old, .. })
3055 !new_binding.span.is_dummy()
3056 && !old_binding.span.is_dummy()
3057 && (new.has_attributes || old.has_attributes)
3060 if old.has_attributes {
3061 Some((new, new_binding.span, true))
3063 Some((old, old_binding.span, true))
3066 // Otherwise prioritize the new binding.
3067 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3068 Some((import, new_binding.span, other.is_import()))
3070 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3071 Some((import, old_binding.span, other.is_import()))
3076 // Check if the target of the use for both bindings is the same.
3077 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3078 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3080 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3081 // Only suggest removing an import if both bindings are to the same def, if both spans
3082 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3083 // been introduced by an item.
3084 let should_remove_import = duplicate
3086 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3089 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3090 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3092 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3093 // Simple case - remove the entire import. Due to the above match arm, this can
3094 // only be a single use so just remove it entirely.
3095 err.tool_only_span_suggestion(
3096 import.use_span_with_attributes,
3097 "remove unnecessary import",
3099 Applicability::MaybeIncorrect,
3102 Some((import, span, _)) => {
3103 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3109 self.name_already_seen.insert(name, span);
3112 /// This function adds a suggestion to change the binding name of a new import that conflicts
3113 /// with an existing import.
3115 /// ```text,ignore (diagnostic)
3116 /// help: you can use `as` to change the binding name of the import
3118 /// LL | use foo::bar as other_bar;
3119 /// | ^^^^^^^^^^^^^^^^^^^^^
3121 fn add_suggestion_for_rename_of_use(
3123 err: &mut DiagnosticBuilder<'_>,
3125 import: &Import<'_>,
3128 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3129 format!("Other{}", name)
3131 format!("other_{}", name)
3134 let mut suggestion = None;
3136 ImportKind::Single { type_ns_only: true, .. } => {
3137 suggestion = Some(format!("self as {}", suggested_name))
3139 ImportKind::Single { source, .. } => {
3141 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3143 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3144 if pos <= snippet.len() {
3145 suggestion = Some(format!(
3149 if snippet.ends_with(';') { ";" } else { "" }
3155 ImportKind::ExternCrate { source, target, .. } => {
3156 suggestion = Some(format!(
3157 "extern crate {} as {};",
3158 source.unwrap_or(target.name),
3162 _ => unreachable!(),
3165 let rename_msg = "you can use `as` to change the binding name of the import";
3166 if let Some(suggestion) = suggestion {
3167 err.span_suggestion(
3171 Applicability::MaybeIncorrect,
3174 err.span_label(binding_span, rename_msg);
3178 /// This function adds a suggestion to remove an unnecessary binding from an import that is
3179 /// nested. In the following example, this function will be invoked to remove the `a` binding
3180 /// in the second use statement:
3182 /// ```ignore (diagnostic)
3183 /// use issue_52891::a;
3184 /// use issue_52891::{d, a, e};
3187 /// The following suggestion will be added:
3189 /// ```ignore (diagnostic)
3190 /// use issue_52891::{d, a, e};
3191 /// ^-- help: remove unnecessary import
3194 /// If the nested use contains only one import then the suggestion will remove the entire
3197 /// It is expected that the provided import is nested - this isn't checked by the
3198 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3199 /// as characters expected by span manipulations won't be present.
3200 fn add_suggestion_for_duplicate_nested_use(
3202 err: &mut DiagnosticBuilder<'_>,
3203 import: &Import<'_>,
3206 assert!(import.is_nested());
3207 let message = "remove unnecessary import";
3209 // Two examples will be used to illustrate the span manipulations we're doing:
3211 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3212 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3213 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3214 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3216 let (found_closing_brace, span) =
3217 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3219 // If there was a closing brace then identify the span to remove any trailing commas from
3220 // previous imports.
3221 if found_closing_brace {
3222 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3223 err.tool_only_span_suggestion(
3227 Applicability::MaybeIncorrect,
3230 // Remove the entire line if we cannot extend the span back, this indicates an
3231 // `issue_52891::{self}` case.
3232 err.span_suggestion(
3233 import.use_span_with_attributes,
3236 Applicability::MaybeIncorrect,
3243 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3246 fn extern_prelude_get(
3250 ) -> Option<&'a NameBinding<'a>> {
3251 if ident.is_path_segment_keyword() {
3252 // Make sure `self`, `super` etc produce an error when passed to here.
3255 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3256 if let Some(binding) = entry.extern_crate_item {
3257 if !speculative && entry.introduced_by_item {
3258 self.record_use(ident, binding, false);
3262 let crate_id = if !speculative {
3263 self.crate_loader.process_path_extern(ident.name, ident.span)
3265 self.crate_loader.maybe_process_path_extern(ident.name)?
3267 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3269 (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
3270 .to_name_binding(self.arenas),
3276 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3277 /// isn't something that can be returned because it can't be made to live that long,
3278 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3279 /// just that an error occurred.
3280 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3281 pub fn resolve_str_path_error(
3287 ) -> Result<(ast::Path, Res), ()> {
3288 let path = if path_str.starts_with("::") {
3291 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3292 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3293 .map(|i| self.new_ast_path_segment(i))
3302 .map(Ident::from_str)
3303 .map(|i| self.new_ast_path_segment(i))
3308 let module = self.get_module(module_id);
3309 let parent_scope = &ParentScope::module(module, self);
3310 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3314 // Resolve a path passed from rustdoc or HIR lowering.
3315 fn resolve_ast_path(
3319 parent_scope: &ParentScope<'a>,
3320 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3321 match self.resolve_path(
3322 &Segment::from_path(path),
3329 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3330 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3331 Ok(path_res.base_res())
3333 PathResult::NonModule(..) => Err((
3335 ResolutionError::FailedToResolve {
3336 label: String::from("type-relative paths are not supported in this context"),
3340 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3341 PathResult::Failed { span, label, suggestion, .. } => {
3342 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3347 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3348 let mut seg = ast::PathSegment::from_ident(ident);
3349 seg.id = self.next_node_id();
3354 pub fn graph_root(&self) -> Module<'a> {
3359 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3363 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3365 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3366 def_id.as_local().map(|def_id| self.definitions.def_span(def_id))
3369 /// Checks if an expression refers to a function marked with
3370 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3371 /// from the attribute.
3372 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3373 if let ExprKind::Path(None, path) = &expr.kind {
3374 // Don't perform legacy const generics rewriting if the path already
3375 // has generic arguments.
3376 if path.segments.last().unwrap().args.is_some() {
3380 let partial_res = self.partial_res_map.get(&expr.id)?;
3381 if partial_res.unresolved_segments() != 0 {
3385 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3386 // We only support cross-crate argument rewriting. Uses
3387 // within the same crate should be updated to use the new
3388 // const generics style.
3389 if def_id.is_local() {
3393 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3397 let parse_attrs = || {
3398 let attrs = self.cstore().item_attrs(def_id, self.session);
3400 attrs.iter().find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
3401 let mut ret = vec![];
3402 for meta in attr.meta_item_list()? {
3403 match meta.literal()?.kind {
3404 LitKind::Int(a, _) => {
3405 ret.push(a as usize);
3407 _ => panic!("invalid arg index"),
3413 // Cache the lookup to avoid parsing attributes for an iterm
3415 let ret = parse_attrs();
3416 self.legacy_const_generic_args.insert(def_id, ret.clone());
3423 fn resolve_main(&mut self) {
3424 let module = self.graph_root;
3425 let ident = Ident::with_dummy_span(sym::main);
3426 let parent_scope = &ParentScope::module(module, self);
3428 let name_binding = match self.resolve_ident_in_module(
3429 ModuleOrUniformRoot::Module(module),
3436 Ok(name_binding) => name_binding,
3440 let res = name_binding.res();
3441 let is_import = name_binding.is_import();
3442 let span = name_binding.span;
3443 if let Res::Def(DefKind::Fn, _) = res {
3444 self.record_use(ident, name_binding, false);
3446 self.main_def = Some(MainDefinition { res, is_import, span });
3450 fn names_to_string(names: &[Symbol]) -> String {
3451 let mut result = String::new();
3452 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3454 result.push_str("::");
3456 if Ident::with_dummy_span(*name).is_raw_guess() {
3457 result.push_str("r#");
3459 result.push_str(&name.as_str());
3464 fn path_names_to_string(path: &Path) -> String {
3465 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3468 /// A somewhat inefficient routine to obtain the name of a module.
3469 fn module_to_string(module: Module<'_>) -> Option<String> {
3470 let mut names = Vec::new();
3472 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3473 if let ModuleKind::Def(.., name) = module.kind {
3474 if let Some(parent) = module.parent {
3476 collect_mod(names, parent);
3479 names.push(Symbol::intern("<opaque>"));
3480 collect_mod(names, module.parent.unwrap());
3483 collect_mod(&mut names, module);
3485 if names.is_empty() {
3489 Some(names_to_string(&names))
3492 #[derive(Copy, Clone, Debug)]
3494 /// Do not issue the lint.
3497 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3498 /// In this case, we can take the span of that path.
3501 /// This lint comes from a `use` statement. In this case, what we
3502 /// care about really is the *root* `use` statement; e.g., if we
3503 /// have nested things like `use a::{b, c}`, we care about the
3505 UsePath { root_id: NodeId, root_span: Span },
3507 /// This is the "trait item" from a fully qualified path. For example,
3508 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3509 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3510 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3514 fn node_id(&self) -> Option<NodeId> {
3516 CrateLint::No => None,
3517 CrateLint::SimplePath(id)
3518 | CrateLint::UsePath { root_id: id, .. }
3519 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3524 pub fn provide(providers: &mut Providers) {
3525 late::lifetimes::provide(providers);