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, 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, MacroKind, SyntaxContext, Transparency};
57 use rustc_span::source_map::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::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(ExpnId),
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> {
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: ExpnId::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 SelfInTyParamDefault,
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 // don't insert between attributes and an item
339 if item.attrs.is_empty() {
340 self.span = Some(item.span.shrink_to_lo());
342 // find the first attribute on the item
343 for attr in &item.attrs {
344 if self.span.map_or(true, |span| attr.span < span) {
345 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<ExpnId>>,
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)>,
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 a 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
832 fn may_appear_after(&self, invoc_parent_expansion: ExpnId, binding: &NameBinding<'_>) -> bool {
833 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
834 // Expansions are partially ordered, so "may appear after" is an inversion of
835 // "certainly appears before or simultaneously" and includes unordered cases.
836 let self_parent_expansion = self.expansion;
837 let other_parent_expansion = binding.expansion;
838 let certainly_before_other_or_simultaneously =
839 other_parent_expansion.is_descendant_of(self_parent_expansion);
840 let certainly_before_invoc_or_simultaneously =
841 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
842 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
846 #[derive(Debug, Default, Clone)]
847 pub struct ExternPreludeEntry<'a> {
848 extern_crate_item: Option<&'a NameBinding<'a>>,
849 pub introduced_by_item: bool,
852 /// Used for better errors for E0773
853 enum BuiltinMacroState {
854 NotYetSeen(SyntaxExtensionKind),
859 resolutions: DeriveResolutions,
860 helper_attrs: Vec<(usize, Ident)>,
861 has_derive_copy: bool,
864 /// The main resolver class.
866 /// This is the visitor that walks the whole crate.
867 pub struct Resolver<'a> {
868 session: &'a Session,
870 definitions: Definitions,
872 graph_root: Module<'a>,
874 prelude: Option<Module<'a>>,
875 extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
877 /// N.B., this is used only for better diagnostics, not name resolution itself.
878 has_self: FxHashSet<DefId>,
880 /// Names of fields of an item `DefId` accessible with dot syntax.
881 /// Used for hints during error reporting.
882 field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
884 /// All imports known to succeed or fail.
885 determined_imports: Vec<&'a Import<'a>>,
887 /// All non-determined imports.
888 indeterminate_imports: Vec<&'a Import<'a>>,
890 /// FIXME: Refactor things so that these fields are passed through arguments and not resolver.
891 /// We are resolving a last import segment during import validation.
892 last_import_segment: bool,
893 /// This binding should be ignored during in-module resolution, so that we don't get
894 /// "self-confirming" import resolutions during import validation.
895 unusable_binding: Option<&'a NameBinding<'a>>,
897 // Spans for local variables found during pattern resolution.
898 // Used for suggestions during error reporting.
899 pat_span_map: NodeMap<Span>,
901 /// Resolutions for nodes that have a single resolution.
902 partial_res_map: NodeMap<PartialRes>,
903 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
904 import_res_map: NodeMap<PerNS<Option<Res>>>,
905 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
906 label_res_map: NodeMap<NodeId>,
908 /// `CrateNum` resolutions of `extern crate` items.
909 extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
910 export_map: ExportMap<LocalDefId>,
911 trait_map: Option<NodeMap<Vec<TraitCandidate>>>,
913 /// A map from nodes to anonymous modules.
914 /// Anonymous modules are pseudo-modules that are implicitly created around items
915 /// contained within blocks.
917 /// For example, if we have this:
925 /// There will be an anonymous module created around `g` with the ID of the
926 /// entry block for `f`.
927 block_map: NodeMap<Module<'a>>,
928 /// A fake module that contains no definition and no prelude. Used so that
929 /// some AST passes can generate identifiers that only resolve to local or
931 empty_module: Module<'a>,
932 module_map: FxHashMap<LocalDefId, Module<'a>>,
933 extern_module_map: FxHashMap<DefId, Module<'a>>,
934 binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,
935 underscore_disambiguator: u32,
937 /// Maps glob imports to the names of items actually imported.
938 glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
939 /// Visibilities in "lowered" form, for all entities that have them.
940 visibilities: FxHashMap<LocalDefId, ty::Visibility>,
941 used_imports: FxHashSet<(NodeId, Namespace)>,
942 maybe_unused_trait_imports: FxHashSet<LocalDefId>,
943 maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
945 /// Privacy errors are delayed until the end in order to deduplicate them.
946 privacy_errors: Vec<PrivacyError<'a>>,
947 /// Ambiguity errors are delayed for deduplication.
948 ambiguity_errors: Vec<AmbiguityError<'a>>,
949 /// `use` injections are delayed for better placement and deduplication.
950 use_injections: Vec<UseError<'a>>,
951 /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
952 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
954 arenas: &'a ResolverArenas<'a>,
955 dummy_binding: &'a NameBinding<'a>,
957 crate_loader: CrateLoader<'a>,
958 macro_names: FxHashSet<Ident>,
959 builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
960 registered_attrs: FxHashSet<Ident>,
961 registered_tools: FxHashSet<Ident>,
962 macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
963 all_macros: FxHashMap<Symbol, Res>,
964 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
965 dummy_ext_bang: Lrc<SyntaxExtension>,
966 dummy_ext_derive: Lrc<SyntaxExtension>,
967 non_macro_attrs: [Lrc<SyntaxExtension>; 2],
968 local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
969 ast_transform_scopes: FxHashMap<ExpnId, Module<'a>>,
970 unused_macros: FxHashMap<LocalDefId, (NodeId, Span)>,
971 proc_macro_stubs: FxHashSet<LocalDefId>,
972 /// Traces collected during macro resolution and validated when it's complete.
973 single_segment_macro_resolutions:
974 Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>,
975 multi_segment_macro_resolutions:
976 Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
977 builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
978 /// `derive(Copy)` marks items they are applied to so they are treated specially later.
979 /// Derive macros cannot modify the item themselves and have to store the markers in the global
980 /// context, so they attach the markers to derive container IDs using this resolver table.
981 containers_deriving_copy: FxHashSet<ExpnId>,
982 /// Parent scopes in which the macros were invoked.
983 /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
984 invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
985 /// `macro_rules` scopes *produced* by expanding the macro invocations,
986 /// include all the `macro_rules` items and other invocations generated by them.
987 output_macro_rules_scopes: FxHashMap<ExpnId, MacroRulesScopeRef<'a>>,
988 /// Helper attributes that are in scope for the given expansion.
989 helper_attrs: FxHashMap<ExpnId, Vec<Ident>>,
990 /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
991 /// with the given `ExpnId`.
992 derive_data: FxHashMap<ExpnId, DeriveData>,
994 /// Avoid duplicated errors for "name already defined".
995 name_already_seen: FxHashMap<Symbol, Span>,
997 potentially_unused_imports: Vec<&'a Import<'a>>,
999 /// Table for mapping struct IDs into struct constructor IDs,
1000 /// it's not used during normal resolution, only for better error reporting.
1001 /// Also includes of list of each fields visibility
1002 struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
1004 /// Features enabled for this crate.
1005 active_features: FxHashSet<Symbol>,
1007 lint_buffer: LintBuffer,
1009 next_node_id: NodeId,
1011 def_id_to_span: IndexVec<LocalDefId, Span>,
1013 node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
1014 def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
1016 /// Indices of unnamed struct or variant fields with unresolved attributes.
1017 placeholder_field_indices: FxHashMap<NodeId, usize>,
1018 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
1019 /// we know what parent node that fragment should be attached to thanks to this table,
1020 /// and how the `impl Trait` fragments were introduced.
1021 invocation_parents: FxHashMap<ExpnId, (LocalDefId, ImplTraitContext)>,
1023 next_disambiguator: FxHashMap<(LocalDefId, DefPathData), u32>,
1024 /// Some way to know that we are in a *trait* impl in `visit_assoc_item`.
1025 /// FIXME: Replace with a more general AST map (together with some other fields).
1026 trait_impl_items: FxHashSet<LocalDefId>,
1028 legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
1030 main_def: Option<MainDefinition>,
1033 /// Nothing really interesting here; it just provides memory for the rest of the crate.
1035 pub struct ResolverArenas<'a> {
1036 modules: TypedArena<ModuleData<'a>>,
1037 local_modules: RefCell<Vec<Module<'a>>>,
1038 imports: TypedArena<Import<'a>>,
1039 name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
1040 ast_paths: TypedArena<ast::Path>,
1041 dropless: DroplessArena,
1044 impl<'a> ResolverArenas<'a> {
1045 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1046 let module = self.modules.alloc(module);
1047 if module.def_id().map_or(true, |def_id| def_id.is_local()) {
1048 self.local_modules.borrow_mut().push(module);
1052 fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
1053 self.local_modules.borrow()
1055 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1056 self.dropless.alloc(name_binding)
1058 fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> {
1059 self.imports.alloc(import)
1061 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1062 self.name_resolutions.alloc(Default::default())
1064 fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> {
1065 PtrKey(self.dropless.alloc(Cell::new(scope)))
1067 fn alloc_macro_rules_binding(
1069 binding: MacroRulesBinding<'a>,
1070 ) -> &'a MacroRulesBinding<'a> {
1071 self.dropless.alloc(binding)
1073 fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
1074 self.ast_paths.alloc_from_iter(paths.iter().cloned())
1076 fn alloc_pattern_spans(&'a self, spans: impl Iterator<Item = Span>) -> &'a [Span] {
1077 self.dropless.alloc_from_iter(spans)
1081 impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
1082 fn as_mut(&mut self) -> &mut Resolver<'a> {
1087 impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
1088 fn parent(self, id: DefId) -> Option<DefId> {
1089 match id.as_local() {
1090 Some(id) => self.definitions.def_key(id).parent,
1091 None => self.cstore().def_key(id).parent,
1093 .map(|index| DefId { index, ..id })
1097 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1098 /// the resolver is no longer needed as all the relevant information is inline.
1099 impl ResolverAstLowering for Resolver<'_> {
1100 fn def_key(&mut self, id: DefId) -> DefKey {
1101 if let Some(id) = id.as_local() {
1102 self.definitions().def_key(id)
1104 self.cstore().def_key(id)
1108 fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
1109 self.cstore().item_generics_num_lifetimes(def_id, sess)
1112 fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
1113 self.legacy_const_generic_args(expr)
1116 fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes> {
1117 self.partial_res_map.get(&id).cloned()
1120 fn get_import_res(&mut self, id: NodeId) -> PerNS<Option<Res>> {
1121 self.import_res_map.get(&id).cloned().unwrap_or_default()
1124 fn get_label_res(&mut self, id: NodeId) -> Option<NodeId> {
1125 self.label_res_map.get(&id).cloned()
1128 fn definitions(&mut self) -> &mut Definitions {
1129 &mut self.definitions
1132 fn lint_buffer(&mut self) -> &mut LintBuffer {
1133 &mut self.lint_buffer
1136 fn next_node_id(&mut self) -> NodeId {
1140 fn take_trait_map(&mut self) -> NodeMap<Vec<TraitCandidate>> {
1141 std::mem::replace(&mut self.trait_map, None).unwrap()
1144 fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
1145 self.node_id_to_def_id.get(&node).copied()
1148 fn local_def_id(&self, node: NodeId) -> LocalDefId {
1149 self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
1152 /// Adds a definition with a parent definition.
1156 node_id: ast::NodeId,
1162 !self.node_id_to_def_id.contains_key(&node_id),
1163 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
1166 self.definitions.def_key(self.node_id_to_def_id[&node_id]),
1169 // Find the next free disambiguator for this key.
1170 let next_disambiguator = &mut self.next_disambiguator;
1171 let next_disambiguator = |parent, data| {
1172 let next_disamb = next_disambiguator.entry((parent, data)).or_insert(0);
1173 let disambiguator = *next_disamb;
1174 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
1178 let def_id = self.definitions.create_def(parent, data, expn_id, next_disambiguator);
1180 assert_eq!(self.def_id_to_span.push(span), def_id);
1182 // Some things for which we allocate `LocalDefId`s don't correspond to
1183 // anything in the AST, so they don't have a `NodeId`. For these cases
1184 // we don't need a mapping from `NodeId` to `LocalDefId`.
1185 if node_id != ast::DUMMY_NODE_ID {
1186 debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id);
1187 self.node_id_to_def_id.insert(node_id, def_id);
1189 assert_eq!(self.def_id_to_node_id.push(node_id), def_id);
1195 impl<'a> Resolver<'a> {
1197 session: &'a Session,
1200 metadata_loader: Box<MetadataLoaderDyn>,
1201 arenas: &'a ResolverArenas<'a>,
1203 let root_local_def_id = LocalDefId { local_def_index: CRATE_DEF_INDEX };
1204 let root_def_id = root_local_def_id.to_def_id();
1205 let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1206 let graph_root = arenas.alloc_module(ModuleData {
1207 no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
1208 ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
1210 let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
1211 let empty_module = arenas.alloc_module(ModuleData {
1212 no_implicit_prelude: true,
1221 let mut module_map = FxHashMap::default();
1222 module_map.insert(root_local_def_id, graph_root);
1224 let definitions = Definitions::new(crate_name, session.local_crate_disambiguator());
1225 let root = definitions.get_root_def();
1227 let mut visibilities = FxHashMap::default();
1228 visibilities.insert(root_local_def_id, ty::Visibility::Public);
1230 let mut def_id_to_span = IndexVec::default();
1231 assert_eq!(def_id_to_span.push(rustc_span::DUMMY_SP), root);
1232 let mut def_id_to_node_id = IndexVec::default();
1233 assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
1234 let mut node_id_to_def_id = FxHashMap::default();
1235 node_id_to_def_id.insert(CRATE_NODE_ID, root);
1237 let mut invocation_parents = FxHashMap::default();
1238 invocation_parents.insert(ExpnId::root(), (root, ImplTraitContext::Existential));
1240 let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
1244 .filter(|(_, entry)| entry.add_prelude)
1245 .map(|(name, _)| (Ident::from_str(name), Default::default()))
1248 if !session.contains_name(&krate.attrs, sym::no_core) {
1249 extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
1250 if !session.contains_name(&krate.attrs, sym::no_std) {
1251 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
1255 let (registered_attrs, registered_tools) =
1256 macros::registered_attrs_and_tools(session, &krate.attrs);
1258 let features = session.features_untracked();
1259 let non_macro_attr =
1260 |mark_used| Lrc::new(SyntaxExtension::non_macro_attr(mark_used, session.edition()));
1262 let mut resolver = Resolver {
1267 // The outermost module has def ID 0; this is not reflected in the
1273 has_self: FxHashSet::default(),
1274 field_names: FxHashMap::default(),
1276 determined_imports: Vec::new(),
1277 indeterminate_imports: Vec::new(),
1279 last_import_segment: false,
1280 unusable_binding: None,
1282 pat_span_map: Default::default(),
1283 partial_res_map: Default::default(),
1284 import_res_map: Default::default(),
1285 label_res_map: Default::default(),
1286 extern_crate_map: Default::default(),
1287 export_map: FxHashMap::default(),
1288 trait_map: Some(NodeMap::default()),
1289 underscore_disambiguator: 0,
1292 block_map: Default::default(),
1293 extern_module_map: FxHashMap::default(),
1294 binding_parent_modules: FxHashMap::default(),
1295 ast_transform_scopes: FxHashMap::default(),
1297 glob_map: Default::default(),
1299 used_imports: FxHashSet::default(),
1300 maybe_unused_trait_imports: Default::default(),
1301 maybe_unused_extern_crates: Vec::new(),
1303 privacy_errors: Vec::new(),
1304 ambiguity_errors: Vec::new(),
1305 use_injections: Vec::new(),
1306 macro_expanded_macro_export_errors: BTreeSet::new(),
1309 dummy_binding: arenas.alloc_name_binding(NameBinding {
1310 kind: NameBindingKind::Res(Res::Err, false),
1312 expansion: ExpnId::root(),
1314 vis: ty::Visibility::Public,
1317 crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
1318 macro_names: FxHashSet::default(),
1319 builtin_macros: Default::default(),
1322 macro_use_prelude: FxHashMap::default(),
1323 all_macros: FxHashMap::default(),
1324 macro_map: FxHashMap::default(),
1325 dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
1326 dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
1327 non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
1328 invocation_parent_scopes: Default::default(),
1329 output_macro_rules_scopes: Default::default(),
1330 helper_attrs: Default::default(),
1331 derive_data: Default::default(),
1332 local_macro_def_scopes: FxHashMap::default(),
1333 name_already_seen: FxHashMap::default(),
1334 potentially_unused_imports: Vec::new(),
1335 struct_constructors: Default::default(),
1336 unused_macros: Default::default(),
1337 proc_macro_stubs: Default::default(),
1338 single_segment_macro_resolutions: Default::default(),
1339 multi_segment_macro_resolutions: Default::default(),
1340 builtin_attrs: Default::default(),
1341 containers_deriving_copy: Default::default(),
1342 active_features: features
1343 .declared_lib_features
1345 .map(|(feat, ..)| *feat)
1346 .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
1348 lint_buffer: LintBuffer::default(),
1349 next_node_id: NodeId::from_u32(1),
1353 placeholder_field_indices: Default::default(),
1355 next_disambiguator: Default::default(),
1356 trait_impl_items: Default::default(),
1357 legacy_const_generic_args: Default::default(),
1358 main_def: Default::default(),
1361 let root_parent_scope = ParentScope::module(graph_root, &resolver);
1362 resolver.invocation_parent_scopes.insert(ExpnId::root(), root_parent_scope);
1367 pub fn next_node_id(&mut self) -> NodeId {
1372 .expect("input too large; ran out of NodeIds");
1373 self.next_node_id = ast::NodeId::from_usize(next);
1377 pub fn lint_buffer(&mut self) -> &mut LintBuffer {
1378 &mut self.lint_buffer
1381 pub fn arenas() -> ResolverArenas<'a> {
1385 pub fn into_outputs(self) -> ResolverOutputs {
1386 let definitions = self.definitions;
1387 let visibilities = self.visibilities;
1388 let extern_crate_map = self.extern_crate_map;
1389 let export_map = self.export_map;
1390 let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
1391 let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
1392 let glob_map = self.glob_map;
1393 let main_def = self.main_def;
1396 cstore: Box::new(self.crate_loader.into_cstore()),
1401 maybe_unused_trait_imports,
1402 maybe_unused_extern_crates,
1403 extern_prelude: self
1406 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1412 pub fn clone_outputs(&self) -> ResolverOutputs {
1414 definitions: self.definitions.clone(),
1415 cstore: Box::new(self.cstore().clone()),
1416 visibilities: self.visibilities.clone(),
1417 extern_crate_map: self.extern_crate_map.clone(),
1418 export_map: self.export_map.clone(),
1419 glob_map: self.glob_map.clone(),
1420 maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
1421 maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
1422 extern_prelude: self
1425 .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
1427 main_def: self.main_def.clone(),
1431 pub fn cstore(&self) -> &CStore {
1432 self.crate_loader.cstore()
1435 fn non_macro_attr(&self, mark_used: bool) -> Lrc<SyntaxExtension> {
1436 self.non_macro_attrs[mark_used as usize].clone()
1439 fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
1441 MacroKind::Bang => self.dummy_ext_bang.clone(),
1442 MacroKind::Derive => self.dummy_ext_derive.clone(),
1443 MacroKind::Attr => self.non_macro_attr(true),
1447 /// Runs the function on each namespace.
1448 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1454 fn is_builtin_macro(&mut self, res: Res) -> bool {
1455 self.get_macro(res).map_or(false, |ext| ext.builtin_name.is_some())
1458 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1460 match ctxt.outer_expn_data().macro_def_id {
1461 Some(def_id) => return def_id,
1462 None => ctxt.remove_mark(),
1467 /// Entry point to crate resolution.
1468 pub fn resolve_crate(&mut self, krate: &Crate) {
1469 self.session.time("resolve_crate", || {
1470 self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
1471 self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
1472 self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
1473 self.session.time("resolve_main", || self.resolve_main());
1474 self.session.time("resolve_check_unused", || self.check_unused(krate));
1475 self.session.time("resolve_report_errors", || self.report_errors(krate));
1476 self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
1480 pub fn traits_in_scope(
1482 current_trait: Option<Module<'a>>,
1483 parent_scope: &ParentScope<'a>,
1484 ctxt: SyntaxContext,
1485 assoc_item: Option<(Symbol, Namespace)>,
1486 ) -> Vec<TraitCandidate> {
1487 let mut found_traits = Vec::new();
1489 if let Some(module) = current_trait {
1490 if self.trait_may_have_item(Some(module), assoc_item) {
1491 let def_id = module.def_id().unwrap();
1492 found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] });
1496 self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
1498 Scope::Module(module, _) => {
1499 this.traits_in_module(module, assoc_item, &mut found_traits);
1501 Scope::StdLibPrelude => {
1502 if let Some(module) = this.prelude {
1503 this.traits_in_module(module, assoc_item, &mut found_traits);
1506 Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {}
1507 _ => unreachable!(),
1515 fn traits_in_module(
1518 assoc_item: Option<(Symbol, Namespace)>,
1519 found_traits: &mut Vec<TraitCandidate>,
1521 module.ensure_traits(self);
1522 let traits = module.traits.borrow();
1523 for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() {
1524 if self.trait_may_have_item(trait_binding.module(), assoc_item) {
1525 let def_id = trait_binding.res().def_id();
1526 let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name);
1527 found_traits.push(TraitCandidate { def_id, import_ids });
1532 // List of traits in scope is pruned on best effort basis. We reject traits not having an
1533 // associated item with the given name and namespace (if specified). This is a conservative
1534 // optimization, proper hygienic type-based resolution of associated items is done in typeck.
1535 // We don't reject trait aliases (`trait_module == None`) because we don't have access to their
1536 // associated items.
1537 fn trait_may_have_item(
1539 trait_module: Option<Module<'a>>,
1540 assoc_item: Option<(Symbol, Namespace)>,
1542 match (trait_module, assoc_item) {
1543 (Some(trait_module), Some((name, ns))) => {
1544 self.resolutions(trait_module).borrow().iter().any(|resolution| {
1545 let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution;
1546 assoc_ns == ns && assoc_ident.name == name
1553 fn find_transitive_imports(
1555 mut kind: &NameBindingKind<'_>,
1557 ) -> SmallVec<[LocalDefId; 1]> {
1558 let mut import_ids = smallvec![];
1559 while let NameBindingKind::Import { import, binding, .. } = kind {
1560 let id = self.local_def_id(import.id);
1561 self.maybe_unused_trait_imports.insert(id);
1562 self.add_to_glob_map(&import, trait_name);
1563 import_ids.push(id);
1564 kind = &binding.kind;
1573 nearest_parent_mod: DefId,
1577 let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
1578 self.arenas.alloc_module(module)
1581 fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey {
1582 let ident = ident.normalize_to_macros_2_0();
1583 let disambiguator = if ident.name == kw::Underscore {
1584 self.underscore_disambiguator += 1;
1585 self.underscore_disambiguator
1589 BindingKey { ident, ns, disambiguator }
1592 fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
1593 if module.populate_on_access.get() {
1594 module.populate_on_access.set(false);
1595 self.build_reduced_graph_external(module);
1597 &module.lazy_resolutions
1604 ) -> &'a RefCell<NameResolution<'a>> {
1606 .resolutions(module)
1609 .or_insert_with(|| self.arenas.alloc_name_resolution())
1616 used_binding: &'a NameBinding<'a>,
1617 is_lexical_scope: bool,
1619 if let Some((b2, kind)) = used_binding.ambiguity {
1620 self.ambiguity_errors.push(AmbiguityError {
1625 misc1: AmbiguityErrorMisc::None,
1626 misc2: AmbiguityErrorMisc::None,
1629 if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind {
1630 // Avoid marking `extern crate` items that refer to a name from extern prelude,
1631 // but not introduce it, as used if they are accessed from lexical scope.
1632 if is_lexical_scope {
1633 if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) {
1634 if let Some(crate_item) = entry.extern_crate_item {
1635 if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item {
1642 import.used.set(true);
1643 self.used_imports.insert((import.id, ns));
1644 self.add_to_glob_map(&import, ident);
1645 self.record_use(ident, ns, binding, false);
1650 fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) {
1651 if import.is_glob() {
1652 let def_id = self.local_def_id(import.id);
1653 self.glob_map.entry(def_id).or_default().insert(ident.name);
1657 /// A generic scope visitor.
1658 /// Visits scopes in order to resolve some identifier in them or perform other actions.
1659 /// If the callback returns `Some` result, we stop visiting scopes and return it.
1662 scope_set: ScopeSet<'a>,
1663 parent_scope: &ParentScope<'a>,
1664 ctxt: SyntaxContext,
1665 mut visitor: impl FnMut(
1668 /*use_prelude*/ bool,
1672 // General principles:
1673 // 1. Not controlled (user-defined) names should have higher priority than controlled names
1674 // built into the language or standard library. This way we can add new names into the
1675 // language or standard library without breaking user code.
1676 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
1677 // Places to search (in order of decreasing priority):
1679 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
1680 // (open set, not controlled).
1681 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1682 // (open, not controlled).
1683 // 3. Extern prelude (open, the open part is from macro expansions, not controlled).
1684 // 4. Tool modules (closed, controlled right now, but not in the future).
1685 // 5. Standard library prelude (de-facto closed, controlled).
1686 // 6. Language prelude (closed, controlled).
1688 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
1689 // (open set, not controlled).
1690 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1691 // (open, not controlled).
1692 // 3. Standard library prelude (de-facto closed, controlled).
1694 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
1695 // are currently reported as errors. They should be higher in priority than preludes
1696 // and probably even names in modules according to the "general principles" above. They
1697 // also should be subject to restricted shadowing because are effectively produced by
1698 // derives (you need to resolve the derive first to add helpers into scope), but they
1699 // should be available before the derive is expanded for compatibility.
1700 // It's mess in general, so we are being conservative for now.
1701 // 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
1702 // priority than prelude macros, but create ambiguities with macros in modules.
1703 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
1704 // (open, not controlled). Have higher priority than prelude macros, but create
1705 // ambiguities with `macro_rules`.
1706 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
1707 // 4a. User-defined prelude from macro-use
1708 // (open, the open part is from macro expansions, not controlled).
1709 // 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
1710 // 4c. Standard library prelude (de-facto closed, controlled).
1711 // 6. Language prelude: builtin attributes (closed, controlled).
1713 let rust_2015 = ctxt.edition() == Edition::Edition2015;
1714 let (ns, macro_kind, is_absolute_path) = match scope_set {
1715 ScopeSet::All(ns, _) => (ns, None, false),
1716 ScopeSet::AbsolutePath(ns) => (ns, None, true),
1717 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
1718 ScopeSet::Late(ns, ..) => (ns, None, false),
1720 let module = match scope_set {
1721 // Start with the specified module.
1722 ScopeSet::Late(_, module, _) => module,
1723 // Jump out of trait or enum modules, they do not act as scopes.
1724 _ => parent_scope.module.nearest_item_scope(),
1726 let mut scope = match ns {
1727 _ if is_absolute_path => Scope::CrateRoot,
1728 TypeNS | ValueNS => Scope::Module(module, None),
1729 MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
1731 let mut ctxt = ctxt.normalize_to_macros_2_0();
1732 let mut use_prelude = !module.no_implicit_prelude;
1735 let visit = match scope {
1736 // Derive helpers are not in scope when resolving derives in the same container.
1737 Scope::DeriveHelpers(expn_id) => {
1738 !(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
1740 Scope::DeriveHelpersCompat => true,
1741 Scope::MacroRules(macro_rules_scope) => {
1742 // Use "path compression" on `macro_rules` scope chains. This is an optimization
1743 // used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
1744 // As another consequence of this optimization visitors never observe invocation
1745 // scopes for macros that were already expanded.
1746 while let MacroRulesScope::Invocation(invoc_id) = macro_rules_scope.get() {
1747 if let Some(next_scope) = self.output_macro_rules_scopes.get(&invoc_id) {
1748 macro_rules_scope.set(next_scope.get());
1755 Scope::CrateRoot => true,
1756 Scope::Module(..) => true,
1757 Scope::RegisteredAttrs => use_prelude,
1758 Scope::MacroUsePrelude => use_prelude || rust_2015,
1759 Scope::BuiltinAttrs => true,
1760 Scope::ExternPrelude => use_prelude || is_absolute_path,
1761 Scope::ToolPrelude => use_prelude,
1762 Scope::StdLibPrelude => use_prelude || ns == MacroNS,
1763 Scope::BuiltinTypes => true,
1767 if let break_result @ Some(..) = visitor(self, scope, use_prelude, ctxt) {
1768 return break_result;
1772 scope = match scope {
1773 Scope::DeriveHelpers(expn_id) if expn_id != ExpnId::root() => {
1774 // Derive helpers are not visible to code generated by bang or derive macros.
1775 let expn_data = expn_id.expn_data();
1776 match expn_data.kind {
1779 kind: MacroKind::Bang | MacroKind::Derive,
1782 } => Scope::DeriveHelpersCompat,
1783 _ => Scope::DeriveHelpers(expn_data.parent),
1786 Scope::DeriveHelpers(..) => Scope::DeriveHelpersCompat,
1787 Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
1788 Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
1789 MacroRulesScope::Binding(binding) => {
1790 Scope::MacroRules(binding.parent_macro_rules_scope)
1792 MacroRulesScope::Invocation(invoc_id) => {
1793 Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
1795 MacroRulesScope::Empty => Scope::Module(module, None),
1797 Scope::CrateRoot => match ns {
1799 ctxt.adjust(ExpnId::root());
1800 Scope::ExternPrelude
1802 ValueNS | MacroNS => break,
1804 Scope::Module(module, prev_lint_id) => {
1805 use_prelude = !module.no_implicit_prelude;
1806 let derive_fallback_lint_id = match scope_set {
1807 ScopeSet::Late(.., lint_id) => lint_id,
1810 match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
1811 Some((parent_module, lint_id)) => {
1812 Scope::Module(parent_module, lint_id.or(prev_lint_id))
1815 ctxt.adjust(ExpnId::root());
1817 TypeNS => Scope::ExternPrelude,
1818 ValueNS => Scope::StdLibPrelude,
1819 MacroNS => Scope::RegisteredAttrs,
1824 Scope::RegisteredAttrs => Scope::MacroUsePrelude,
1825 Scope::MacroUsePrelude => Scope::StdLibPrelude,
1826 Scope::BuiltinAttrs => break, // nowhere else to search
1827 Scope::ExternPrelude if is_absolute_path => break,
1828 Scope::ExternPrelude => Scope::ToolPrelude,
1829 Scope::ToolPrelude => Scope::StdLibPrelude,
1830 Scope::StdLibPrelude => match ns {
1831 TypeNS => Scope::BuiltinTypes,
1832 ValueNS => break, // nowhere else to search
1833 MacroNS => Scope::BuiltinAttrs,
1835 Scope::BuiltinTypes => break, // nowhere else to search
1842 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1843 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1844 /// `ident` in the first scope that defines it (or None if no scopes define it).
1846 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1847 /// the items are defined in the block. For example,
1850 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1853 /// g(); // This resolves to the local variable `g` since it shadows the item.
1857 /// Invariant: This must only be called during main resolution, not during
1858 /// import resolution.
1859 fn resolve_ident_in_lexical_scope(
1863 parent_scope: &ParentScope<'a>,
1864 record_used_id: Option<NodeId>,
1867 ) -> Option<LexicalScopeBinding<'a>> {
1868 assert!(ns == TypeNS || ns == ValueNS);
1869 let orig_ident = ident;
1870 if ident.name == kw::Empty {
1871 return Some(LexicalScopeBinding::Res(Res::Err));
1873 let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
1874 // FIXME(jseyfried) improve `Self` hygiene
1875 let empty_span = ident.span.with_ctxt(SyntaxContext::root());
1876 (empty_span, empty_span)
1877 } else if ns == TypeNS {
1878 let normalized_span = ident.span.normalize_to_macros_2_0();
1879 (normalized_span, normalized_span)
1881 (ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
1883 ident.span = general_span;
1884 let normalized_ident = Ident { span: normalized_span, ..ident };
1886 // Walk backwards up the ribs in scope.
1887 let record_used = record_used_id.is_some();
1888 let mut module = self.graph_root;
1889 for i in (0..ribs.len()).rev() {
1890 debug!("walk rib\n{:?}", ribs[i].bindings);
1891 // Use the rib kind to determine whether we are resolving parameters
1892 // (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
1893 let rib_ident = if ribs[i].kind.contains_params() { normalized_ident } else { ident };
1894 if let Some((original_rib_ident_def, res)) = ribs[i].bindings.get_key_value(&rib_ident)
1896 // The ident resolves to a type parameter or local variable.
1897 return Some(LexicalScopeBinding::Res(self.validate_res_from_ribs(
1903 *original_rib_ident_def,
1908 module = match ribs[i].kind {
1909 ModuleRibKind(module) => module,
1910 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1911 // If an invocation of this macro created `ident`, give up on `ident`
1912 // and switch to `ident`'s source from the macro definition.
1913 ident.span.remove_mark();
1920 ModuleKind::Block(..) => {} // We can see through blocks
1924 let item = self.resolve_ident_in_module_unadjusted(
1925 ModuleOrUniformRoot::Module(module),
1932 if let Ok(binding) = item {
1933 // The ident resolves to an item.
1934 return Some(LexicalScopeBinding::Item(binding));
1937 self.early_resolve_ident_in_lexical_scope(
1939 ScopeSet::Late(ns, module, record_used_id),
1946 .map(LexicalScopeBinding::Item)
1949 fn hygienic_lexical_parent(
1952 ctxt: &mut SyntaxContext,
1953 derive_fallback_lint_id: Option<NodeId>,
1954 ) -> Option<(Module<'a>, Option<NodeId>)> {
1955 if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
1956 return Some((self.macro_def_scope(ctxt.remove_mark()), None));
1959 if let ModuleKind::Block(..) = module.kind {
1960 return Some((module.parent.unwrap().nearest_item_scope(), None));
1963 // We need to support the next case under a deprecation warning
1966 // ---- begin: this comes from a proc macro derive
1967 // mod implementation_details {
1968 // // Note that `MyStruct` is not in scope here.
1969 // impl SomeTrait for MyStruct { ... }
1973 // So we have to fall back to the module's parent during lexical resolution in this case.
1974 if derive_fallback_lint_id.is_some() {
1975 if let Some(parent) = module.parent {
1976 // Inner module is inside the macro, parent module is outside of the macro.
1977 if module.expansion != parent.expansion
1978 && module.expansion.is_descendant_of(parent.expansion)
1980 // The macro is a proc macro derive
1981 if let Some(def_id) = module.expansion.expn_data().macro_def_id {
1982 let ext = self.get_macro_by_def_id(def_id);
1983 if ext.builtin_name.is_none()
1984 && ext.macro_kind() == MacroKind::Derive
1985 && parent.expansion.outer_expn_is_descendant_of(*ctxt)
1987 return Some((parent, derive_fallback_lint_id));
1997 fn resolve_ident_in_module(
1999 module: ModuleOrUniformRoot<'a>,
2002 parent_scope: &ParentScope<'a>,
2005 ) -> Result<&'a NameBinding<'a>, Determinacy> {
2006 self.resolve_ident_in_module_ext(module, ident, ns, parent_scope, record_used, path_span)
2007 .map_err(|(determinacy, _)| determinacy)
2010 fn resolve_ident_in_module_ext(
2012 module: ModuleOrUniformRoot<'a>,
2015 parent_scope: &ParentScope<'a>,
2018 ) -> Result<&'a NameBinding<'a>, (Determinacy, Weak)> {
2019 let tmp_parent_scope;
2020 let mut adjusted_parent_scope = parent_scope;
2022 ModuleOrUniformRoot::Module(m) => {
2023 if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(m.expansion) {
2025 ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
2026 adjusted_parent_scope = &tmp_parent_scope;
2029 ModuleOrUniformRoot::ExternPrelude => {
2030 ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
2032 ModuleOrUniformRoot::CrateRootAndExternPrelude | ModuleOrUniformRoot::CurrentScope => {
2036 self.resolve_ident_in_module_unadjusted_ext(
2040 adjusted_parent_scope,
2047 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2048 debug!("resolve_crate_root({:?})", ident);
2049 let mut ctxt = ident.span.ctxt();
2050 let mark = if ident.name == kw::DollarCrate {
2051 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2052 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2053 // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks.
2054 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2055 // definitions actually produced by `macro` and `macro` definitions produced by
2056 // `macro_rules!`, but at least such configurations are not stable yet.
2057 ctxt = ctxt.normalize_to_macro_rules();
2059 "resolve_crate_root: marks={:?}",
2060 ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::<Vec<_>>()
2062 let mut iter = ctxt.marks().into_iter().rev().peekable();
2063 let mut result = None;
2064 // Find the last opaque mark from the end if it exists.
2065 while let Some(&(mark, transparency)) = iter.peek() {
2066 if transparency == Transparency::Opaque {
2067 result = Some(mark);
2074 "resolve_crate_root: found opaque mark {:?} {:?}",
2076 result.map(|r| r.expn_data())
2078 // Then find the last semi-transparent mark from the end if it exists.
2079 for (mark, transparency) in iter {
2080 if transparency == Transparency::SemiTransparent {
2081 result = Some(mark);
2087 "resolve_crate_root: found semi-transparent mark {:?} {:?}",
2089 result.map(|r| r.expn_data())
2093 debug!("resolve_crate_root: not DollarCrate");
2094 ctxt = ctxt.normalize_to_macros_2_0();
2095 ctxt.adjust(ExpnId::root())
2097 let module = match mark {
2098 Some(def) => self.macro_def_scope(def),
2101 "resolve_crate_root({:?}): found no mark (ident.span = {:?})",
2104 return self.graph_root;
2107 let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
2109 "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
2118 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2119 let mut module = self.get_module(module.nearest_parent_mod);
2120 while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
2121 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2122 module = self.get_module(parent.nearest_parent_mod);
2130 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2131 parent_scope: &ParentScope<'a>,
2134 crate_lint: CrateLint,
2135 ) -> PathResult<'a> {
2136 self.resolve_path_with_ribs(
2147 fn resolve_path_with_ribs(
2150 opt_ns: Option<Namespace>, // `None` indicates a module path in import
2151 parent_scope: &ParentScope<'a>,
2154 crate_lint: CrateLint,
2155 ribs: Option<&PerNS<Vec<Rib<'a>>>>,
2156 ) -> PathResult<'a> {
2157 let mut module = None;
2158 let mut allow_super = true;
2159 let mut second_binding = None;
2162 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
2163 path_span={:?}, crate_lint={:?})",
2164 path, opt_ns, record_used, path_span, crate_lint,
2167 for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
2168 debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
2169 let record_segment_res = |this: &mut Self, res| {
2171 if let Some(id) = id {
2172 if !this.partial_res_map.contains_key(&id) {
2173 assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
2174 this.record_partial_res(id, PartialRes::new(res));
2180 let is_last = i == path.len() - 1;
2181 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
2182 let name = ident.name;
2184 allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
2187 if allow_super && name == kw::Super {
2188 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2189 let self_module = match i {
2190 0 => Some(self.resolve_self(&mut ctxt, parent_scope.module)),
2192 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
2196 if let Some(self_module) = self_module {
2197 if let Some(parent) = self_module.parent {
2198 module = Some(ModuleOrUniformRoot::Module(
2199 self.resolve_self(&mut ctxt, parent),
2204 let msg = "there are too many leading `super` keywords".to_string();
2205 return PathResult::Failed {
2209 is_error_from_last_segment: false,
2213 if name == kw::SelfLower {
2214 let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
2215 module = Some(ModuleOrUniformRoot::Module(
2216 self.resolve_self(&mut ctxt, parent_scope.module),
2220 if name == kw::PathRoot && ident.span.rust_2018() {
2221 module = Some(ModuleOrUniformRoot::ExternPrelude);
2224 if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
2225 // `::a::b` from 2015 macro on 2018 global edition
2226 module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
2229 if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
2230 // `::a::b`, `crate::a::b` or `$crate::a::b`
2231 module = Some(ModuleOrUniformRoot::Module(self.resolve_crate_root(ident)));
2237 // Report special messages for path segment keywords in wrong positions.
2238 if ident.is_path_segment_keyword() && i != 0 {
2239 let name_str = if name == kw::PathRoot {
2240 "crate root".to_string()
2242 format!("`{}`", name)
2244 let label = if i == 1 && path[0].ident.name == kw::PathRoot {
2245 format!("global paths cannot start with {}", name_str)
2247 format!("{} in paths can only be used in start position", name_str)
2249 return PathResult::Failed {
2253 is_error_from_last_segment: false,
2257 enum FindBindingResult<'a> {
2258 Binding(Result<&'a NameBinding<'a>, Determinacy>),
2259 PathResult(PathResult<'a>),
2261 let find_binding_in_ns = |this: &mut Self, ns| {
2262 let binding = if let Some(module) = module {
2263 this.resolve_ident_in_module(
2271 } else if ribs.is_none() || opt_ns.is_none() || opt_ns == Some(MacroNS) {
2272 let scopes = ScopeSet::All(ns, opt_ns.is_none());
2273 this.early_resolve_ident_in_lexical_scope(
2282 let record_used_id = if record_used {
2283 crate_lint.node_id().or(Some(CRATE_NODE_ID))
2287 match this.resolve_ident_in_lexical_scope(
2295 // we found a locally-imported or available item/module
2296 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
2297 // we found a local variable or type param
2298 Some(LexicalScopeBinding::Res(res))
2299 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) =>
2301 record_segment_res(this, res);
2302 return FindBindingResult::PathResult(PathResult::NonModule(
2303 PartialRes::with_unresolved_segments(res, path.len() - 1),
2306 _ => Err(Determinacy::determined(record_used)),
2309 FindBindingResult::Binding(binding)
2311 let binding = match find_binding_in_ns(self, ns) {
2312 FindBindingResult::PathResult(x) => return x,
2313 FindBindingResult::Binding(binding) => binding,
2318 second_binding = Some(binding);
2320 let res = binding.res();
2321 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
2322 if let Some(next_module) = binding.module() {
2323 module = Some(ModuleOrUniformRoot::Module(next_module));
2324 record_segment_res(self, res);
2325 } else if res == Res::ToolMod && i + 1 != path.len() {
2326 if binding.is_import() {
2330 "cannot use a tool module through an import",
2332 .span_note(binding.span, "the tool module imported here")
2335 let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
2336 return PathResult::NonModule(PartialRes::new(res));
2337 } else if res == Res::Err {
2338 return PathResult::NonModule(PartialRes::new(Res::Err));
2339 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
2340 self.lint_if_path_starts_with_module(
2346 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2351 let label = format!(
2352 "`{}` is {} {}, not a module",
2358 return PathResult::Failed {
2362 is_error_from_last_segment: is_last,
2366 Err(Undetermined) => return PathResult::Indeterminate,
2367 Err(Determined) => {
2368 if let Some(ModuleOrUniformRoot::Module(module)) = module {
2369 if opt_ns.is_some() && !module.is_normal() {
2370 return PathResult::NonModule(PartialRes::with_unresolved_segments(
2371 module.res().unwrap(),
2376 let module_res = match module {
2377 Some(ModuleOrUniformRoot::Module(module)) => module.res(),
2380 let (label, suggestion) = if module_res == self.graph_root.res() {
2381 let is_mod = |res| matches!(res, Res::Def(DefKind::Mod, _));
2382 // Don't look up import candidates if this is a speculative resolve
2383 let mut candidates = if record_used {
2384 self.lookup_import_candidates(ident, TypeNS, parent_scope, is_mod)
2388 candidates.sort_by_cached_key(|c| {
2389 (c.path.segments.len(), pprust::path_to_string(&c.path))
2391 if let Some(candidate) = candidates.get(0) {
2393 String::from("unresolved import"),
2395 vec![(ident.span, pprust::path_to_string(&candidate.path))],
2396 String::from("a similar path exists"),
2397 Applicability::MaybeIncorrect,
2400 } else if self.session.edition() == Edition::Edition2015 {
2401 (format!("maybe a missing crate `{}`?", ident), None)
2403 (format!("could not find `{}` in the crate root", ident), None)
2411 .map_or(false, |c| c.is_ascii_uppercase())
2413 // Check whether the name refers to an item in the value namespace.
2414 let suggestion = if ribs.is_some() {
2415 let match_span = match self.resolve_ident_in_lexical_scope(
2421 &ribs.unwrap()[ValueNS],
2423 // Name matches a local variable. For example:
2426 // let Foo: &str = "";
2427 // println!("{}", Foo::Bar); // Name refers to local
2428 // // variable `Foo`.
2431 Some(LexicalScopeBinding::Res(Res::Local(id))) => {
2432 Some(*self.pat_span_map.get(&id).unwrap())
2435 // Name matches item from a local name binding
2436 // created by `use` declaration. For example:
2438 // pub Foo: &str = "";
2442 // println!("{}", Foo::Bar); // Name refers to local
2443 // // binding `Foo`.
2446 Some(LexicalScopeBinding::Item(name_binding)) => {
2447 Some(name_binding.span)
2452 if let Some(span) = match_span {
2454 vec![(span, String::from(""))],
2455 format!("`{}` is defined here, but is not a type", ident),
2456 Applicability::MaybeIncorrect,
2465 (format!("use of undeclared type `{}`", ident), suggestion)
2467 (format!("use of undeclared crate or module `{}`", ident), None)
2470 let parent = path[i - 1].ident.name;
2471 let parent = match parent {
2472 // ::foo is mounted at the crate root for 2015, and is the extern
2473 // prelude for 2018+
2474 kw::PathRoot if self.session.edition() > Edition::Edition2015 => {
2475 "the list of imported crates".to_owned()
2477 kw::PathRoot | kw::Crate => "the crate root".to_owned(),
2479 format!("`{}`", parent)
2483 let mut msg = format!("could not find `{}` in {}", ident, parent);
2484 if ns == TypeNS || ns == ValueNS {
2485 let ns_to_try = if ns == TypeNS { ValueNS } else { TypeNS };
2486 if let FindBindingResult::Binding(Ok(binding)) =
2487 find_binding_in_ns(self, ns_to_try)
2489 let mut found = |what| {
2491 "expected {}, found {} `{}` in {}",
2498 if binding.module().is_some() {
2501 match binding.res() {
2502 def::Res::<NodeId>::Def(kind, id) => found(kind.descr(id)),
2503 _ => found(ns_to_try.descr()),
2510 return PathResult::Failed {
2514 is_error_from_last_segment: is_last,
2520 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
2522 PathResult::Module(match module {
2523 Some(module) => module,
2524 None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
2525 _ => span_bug!(path_span, "resolve_path: non-empty path `{:?}` has no module", path),
2529 fn lint_if_path_starts_with_module(
2531 crate_lint: CrateLint,
2534 second_binding: Option<&NameBinding<'_>>,
2536 let (diag_id, diag_span) = match crate_lint {
2537 CrateLint::No => return,
2538 CrateLint::SimplePath(id) => (id, path_span),
2539 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
2540 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
2543 let first_name = match path.get(0) {
2544 // In the 2018 edition this lint is a hard error, so nothing to do
2545 Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
2549 // We're only interested in `use` paths which should start with
2550 // `{{root}}` currently.
2551 if first_name != kw::PathRoot {
2556 // If this import looks like `crate::...` it's already good
2557 Some(Segment { ident, .. }) if ident.name == kw::Crate => return,
2558 // Otherwise go below to see if it's an extern crate
2560 // If the path has length one (and it's `PathRoot` most likely)
2561 // then we don't know whether we're gonna be importing a crate or an
2562 // item in our crate. Defer this lint to elsewhere
2566 // If the first element of our path was actually resolved to an
2567 // `ExternCrate` (also used for `crate::...`) then no need to issue a
2568 // warning, this looks all good!
2569 if let Some(binding) = second_binding {
2570 if let NameBindingKind::Import { import, .. } = binding.kind {
2571 // Careful: we still want to rewrite paths from renamed extern crates.
2572 if let ImportKind::ExternCrate { source: None, .. } = import.kind {
2578 let diag = BuiltinLintDiagnostics::AbsPathWithModule(diag_span);
2579 self.lint_buffer.buffer_lint_with_diagnostic(
2580 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
2583 "absolute paths must start with `self`, `super`, \
2584 `crate`, or an external crate name in the 2018 edition",
2589 // Validate a local resolution (from ribs).
2590 fn validate_res_from_ribs(
2597 original_rib_ident_def: Ident,
2598 all_ribs: &[Rib<'a>],
2600 const CG_BUG_STR: &str = "min_const_generics resolve check didn't stop compilation";
2601 debug!("validate_res_from_ribs({:?})", res);
2602 let ribs = &all_ribs[rib_index + 1..];
2604 // An invalid forward use of a generic parameter from a previous default.
2605 if let ForwardGenericParamBanRibKind = all_ribs[rib_index].kind {
2607 let res_error = if rib_ident.name == kw::SelfUpper {
2608 ResolutionError::SelfInTyParamDefault
2610 ResolutionError::ForwardDeclaredGenericParam
2612 self.report_error(span, res_error);
2614 assert_eq!(res, Res::Err);
2620 use ResolutionError::*;
2621 let mut res_err = None;
2626 | ClosureOrAsyncRibKind
2628 | MacroDefinition(..)
2629 | ForwardGenericParamBanRibKind => {
2630 // Nothing to do. Continue.
2632 ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
2633 // This was an attempt to access an upvar inside a
2634 // named function item. This is not allowed, so we
2637 // We don't immediately trigger a resolve error, because
2638 // we want certain other resolution errors (namely those
2639 // emitted for `ConstantItemRibKind` below) to take
2641 res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
2644 ConstantItemRibKind(_, item) => {
2645 // Still doesn't deal with upvars
2647 let (span, resolution_error) =
2648 if let Some((ident, constant_item_kind)) = item {
2649 let kind_str = match constant_item_kind {
2650 ConstantItemKind::Const => "const",
2651 ConstantItemKind::Static => "static",
2655 AttemptToUseNonConstantValueInConstant(
2656 ident, "let", kind_str,
2662 AttemptToUseNonConstantValueInConstant(
2663 original_rib_ident_def,
2669 self.report_error(span, resolution_error);
2673 ConstParamTyRibKind => {
2675 self.report_error(span, ParamInTyOfConstParam(rib_ident.name));
2681 if let Some(res_err) = res_err {
2682 self.report_error(span, res_err);
2686 Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
2688 let has_generic_params: HasGenericParams = match rib.kind {
2690 | ClosureOrAsyncRibKind
2693 | MacroDefinition(..)
2694 | ForwardGenericParamBanRibKind => {
2695 // Nothing to do. Continue.
2699 ConstantItemRibKind(trivial, _) => {
2700 let features = self.session.features_untracked();
2701 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2703 || features.const_generics
2704 || features.lazy_normalization_consts)
2706 // HACK(min_const_generics): If we encounter `Self` in an anonymous constant
2707 // we can't easily tell if it's generic at this stage, so we instead remember
2708 // this and then enforce the self type to be concrete later on.
2709 if let Res::SelfTy(trait_def, Some((impl_def, _))) = res {
2710 res = Res::SelfTy(trait_def, Some((impl_def, true)));
2715 ResolutionError::ParamInNonTrivialAnonConst {
2716 name: rib_ident.name,
2722 self.session.delay_span_bug(span, CG_BUG_STR);
2730 // This was an attempt to use a type parameter outside its scope.
2731 ItemRibKind(has_generic_params) => has_generic_params,
2732 FnItemRibKind => HasGenericParams::Yes,
2733 ConstParamTyRibKind => {
2737 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2747 ResolutionError::GenericParamsFromOuterFunction(
2756 Res::Def(DefKind::ConstParam, _) => {
2757 let mut ribs = ribs.iter().peekable();
2758 if let Some(Rib { kind: FnItemRibKind, .. }) = ribs.peek() {
2759 // When declaring const parameters inside function signatures, the first rib
2760 // is always a `FnItemRibKind`. In this case, we can skip it, to avoid it
2761 // (spuriously) conflicting with the const param.
2766 let has_generic_params = match rib.kind {
2768 | ClosureOrAsyncRibKind
2771 | MacroDefinition(..)
2772 | ForwardGenericParamBanRibKind => continue,
2774 ConstantItemRibKind(trivial, _) => {
2775 let features = self.session.features_untracked();
2776 // HACK(min_const_generics): We currently only allow `N` or `{ N }`.
2778 || features.const_generics
2779 || features.lazy_normalization_consts)
2784 ResolutionError::ParamInNonTrivialAnonConst {
2785 name: rib_ident.name,
2791 self.session.delay_span_bug(span, CG_BUG_STR);
2798 ItemRibKind(has_generic_params) => has_generic_params,
2799 FnItemRibKind => HasGenericParams::Yes,
2800 ConstParamTyRibKind => {
2804 ResolutionError::ParamInTyOfConstParam(rib_ident.name),
2811 // This was an attempt to use a const parameter outside its scope.
2815 ResolutionError::GenericParamsFromOuterFunction(
2829 fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) {
2830 debug!("(recording res) recording {:?} for {}", resolution, node_id);
2831 if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) {
2832 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
2836 fn record_pat_span(&mut self, node: NodeId, span: Span) {
2837 debug!("(recording pat) recording {:?} for {:?}", node, span);
2838 self.pat_span_map.insert(node, span);
2841 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
2842 vis.is_accessible_from(module.nearest_parent_mod, self)
2845 fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
2846 if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
2847 if !ptr::eq(module, old_module) {
2848 span_bug!(binding.span, "parent module is reset for binding");
2853 fn disambiguate_macro_rules_vs_modularized(
2855 macro_rules: &'a NameBinding<'a>,
2856 modularized: &'a NameBinding<'a>,
2858 // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules"
2859 // is disambiguated to mitigate regressions from macro modularization.
2860 // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
2862 self.binding_parent_modules.get(&PtrKey(macro_rules)),
2863 self.binding_parent_modules.get(&PtrKey(modularized)),
2865 (Some(macro_rules), Some(modularized)) => {
2866 macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
2867 && modularized.is_ancestor_of(macro_rules)
2873 fn report_errors(&mut self, krate: &Crate) {
2874 self.report_with_use_injections(krate);
2876 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
2877 let msg = "macro-expanded `macro_export` macros from the current crate \
2878 cannot be referred to by absolute paths";
2879 self.lint_buffer.buffer_lint_with_diagnostic(
2880 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
2884 BuiltinLintDiagnostics::MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
2888 for ambiguity_error in &self.ambiguity_errors {
2889 self.report_ambiguity_error(ambiguity_error);
2892 let mut reported_spans = FxHashSet::default();
2893 for error in &self.privacy_errors {
2894 if reported_spans.insert(error.dedup_span) {
2895 self.report_privacy_error(error);
2900 fn report_with_use_injections(&mut self, krate: &Crate) {
2901 for UseError { mut err, candidates, def_id, instead, suggestion } in
2902 self.use_injections.drain(..)
2904 let (span, found_use) = if let Some(def_id) = def_id.as_local() {
2905 UsePlacementFinder::check(krate, self.def_id_to_node_id[def_id])
2909 if !candidates.is_empty() {
2910 diagnostics::show_candidates(&mut err, span, &candidates, instead, found_use);
2911 } else if let Some((span, msg, sugg, appl)) = suggestion {
2912 err.span_suggestion(span, msg, sugg, appl);
2918 fn report_conflict<'b>(
2923 new_binding: &NameBinding<'b>,
2924 old_binding: &NameBinding<'b>,
2926 // Error on the second of two conflicting names
2927 if old_binding.span.lo() > new_binding.span.lo() {
2928 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
2931 let container = match parent.kind {
2932 ModuleKind::Def(kind, _, _) => kind.descr(parent.def_id().unwrap()),
2933 ModuleKind::Block(..) => "block",
2936 let old_noun = match old_binding.is_import() {
2938 false => "definition",
2941 let new_participle = match new_binding.is_import() {
2947 (ident.name, self.session.source_map().guess_head_span(new_binding.span));
2949 if let Some(s) = self.name_already_seen.get(&name) {
2955 let old_kind = match (ns, old_binding.module()) {
2956 (ValueNS, _) => "value",
2957 (MacroNS, _) => "macro",
2958 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
2959 (TypeNS, Some(module)) if module.is_normal() => "module",
2960 (TypeNS, Some(module)) if module.is_trait() => "trait",
2961 (TypeNS, _) => "type",
2964 let msg = format!("the name `{}` is defined multiple times", name);
2966 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
2967 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
2968 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
2969 true => struct_span_err!(self.session, span, E0254, "{}", msg),
2970 false => struct_span_err!(self.session, span, E0260, "{}", msg),
2972 _ => match (old_binding.is_import(), new_binding.is_import()) {
2973 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
2974 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
2975 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
2980 "`{}` must be defined only once in the {} namespace of this {}",
2986 err.span_label(span, format!("`{}` re{} here", name, new_participle));
2988 self.session.source_map().guess_head_span(old_binding.span),
2989 format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
2992 // See https://github.com/rust-lang/rust/issues/32354
2993 use NameBindingKind::Import;
2994 let import = match (&new_binding.kind, &old_binding.kind) {
2995 // If there are two imports where one or both have attributes then prefer removing the
2996 // import without attributes.
2997 (Import { import: new, .. }, Import { import: old, .. })
2999 !new_binding.span.is_dummy()
3000 && !old_binding.span.is_dummy()
3001 && (new.has_attributes || old.has_attributes)
3004 if old.has_attributes {
3005 Some((new, new_binding.span, true))
3007 Some((old, old_binding.span, true))
3010 // Otherwise prioritize the new binding.
3011 (Import { import, .. }, other) if !new_binding.span.is_dummy() => {
3012 Some((import, new_binding.span, other.is_import()))
3014 (other, Import { import, .. }) if !old_binding.span.is_dummy() => {
3015 Some((import, old_binding.span, other.is_import()))
3020 // Check if the target of the use for both bindings is the same.
3021 let duplicate = new_binding.res().opt_def_id() == old_binding.res().opt_def_id();
3022 let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
3024 self.extern_prelude.get(&ident).map_or(true, |entry| entry.introduced_by_item);
3025 // Only suggest removing an import if both bindings are to the same def, if both spans
3026 // aren't dummy spans. Further, if both bindings are imports, then the ident must have
3027 // been introduced by a item.
3028 let should_remove_import = duplicate
3030 && ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
3033 Some((import, span, true)) if should_remove_import && import.is_nested() => {
3034 self.add_suggestion_for_duplicate_nested_use(&mut err, import, span)
3036 Some((import, _, true)) if should_remove_import && !import.is_glob() => {
3037 // Simple case - remove the entire import. Due to the above match arm, this can
3038 // only be a single use so just remove it entirely.
3039 err.tool_only_span_suggestion(
3040 import.use_span_with_attributes,
3041 "remove unnecessary import",
3043 Applicability::MaybeIncorrect,
3046 Some((import, span, _)) => {
3047 self.add_suggestion_for_rename_of_use(&mut err, name, import, span)
3053 self.name_already_seen.insert(name, span);
3056 /// This function adds a suggestion to change the binding name of a new import that conflicts
3057 /// with an existing import.
3059 /// ```text,ignore (diagnostic)
3060 /// help: you can use `as` to change the binding name of the import
3062 /// LL | use foo::bar as other_bar;
3063 /// | ^^^^^^^^^^^^^^^^^^^^^
3065 fn add_suggestion_for_rename_of_use(
3067 err: &mut DiagnosticBuilder<'_>,
3069 import: &Import<'_>,
3072 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
3073 format!("Other{}", name)
3075 format!("other_{}", name)
3078 let mut suggestion = None;
3080 ImportKind::Single { type_ns_only: true, .. } => {
3081 suggestion = Some(format!("self as {}", suggested_name))
3083 ImportKind::Single { source, .. } => {
3085 source.span.hi().0.checked_sub(binding_span.lo().0).map(|pos| pos as usize)
3087 if let Ok(snippet) = self.session.source_map().span_to_snippet(binding_span) {
3088 if pos <= snippet.len() {
3089 suggestion = Some(format!(
3093 if snippet.ends_with(';') { ";" } else { "" }
3099 ImportKind::ExternCrate { source, target, .. } => {
3100 suggestion = Some(format!(
3101 "extern crate {} as {};",
3102 source.unwrap_or(target.name),
3106 _ => unreachable!(),
3109 let rename_msg = "you can use `as` to change the binding name of the import";
3110 if let Some(suggestion) = suggestion {
3111 err.span_suggestion(
3115 Applicability::MaybeIncorrect,
3118 err.span_label(binding_span, rename_msg);
3122 /// This function adds a suggestion to remove a unnecessary binding from an import that is
3123 /// nested. In the following example, this function will be invoked to remove the `a` binding
3124 /// in the second use statement:
3126 /// ```ignore (diagnostic)
3127 /// use issue_52891::a;
3128 /// use issue_52891::{d, a, e};
3131 /// The following suggestion will be added:
3133 /// ```ignore (diagnostic)
3134 /// use issue_52891::{d, a, e};
3135 /// ^-- help: remove unnecessary import
3138 /// If the nested use contains only one import then the suggestion will remove the entire
3141 /// It is expected that the provided import is nested - this isn't checked by the
3142 /// function. If this invariant is not upheld, this function's behaviour will be unexpected
3143 /// as characters expected by span manipulations won't be present.
3144 fn add_suggestion_for_duplicate_nested_use(
3146 err: &mut DiagnosticBuilder<'_>,
3147 import: &Import<'_>,
3150 assert!(import.is_nested());
3151 let message = "remove unnecessary import";
3153 // Two examples will be used to illustrate the span manipulations we're doing:
3155 // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
3156 // `a` and `import.use_span` is `issue_52891::{d, a, e};`.
3157 // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
3158 // `a` and `import.use_span` is `issue_52891::{d, e, a};`.
3160 let (found_closing_brace, span) =
3161 find_span_of_binding_until_next_binding(self.session, binding_span, import.use_span);
3163 // If there was a closing brace then identify the span to remove any trailing commas from
3164 // previous imports.
3165 if found_closing_brace {
3166 if let Some(span) = extend_span_to_previous_binding(self.session, span) {
3167 err.tool_only_span_suggestion(
3171 Applicability::MaybeIncorrect,
3174 // Remove the entire line if we cannot extend the span back, this indicates a
3175 // `issue_52891::{self}` case.
3176 err.span_suggestion(
3177 import.use_span_with_attributes,
3180 Applicability::MaybeIncorrect,
3187 err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
3190 fn extern_prelude_get(
3194 ) -> Option<&'a NameBinding<'a>> {
3195 if ident.is_path_segment_keyword() {
3196 // Make sure `self`, `super` etc produce an error when passed to here.
3199 self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| {
3200 if let Some(binding) = entry.extern_crate_item {
3201 if !speculative && entry.introduced_by_item {
3202 self.record_use(ident, TypeNS, binding, false);
3206 let crate_id = if !speculative {
3207 self.crate_loader.process_path_extern(ident.name, ident.span)
3209 self.crate_loader.maybe_process_path_extern(ident.name)?
3211 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
3213 (crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
3214 .to_name_binding(self.arenas),
3220 /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
3221 /// isn't something that can be returned because it can't be made to live that long,
3222 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
3223 /// just that an error occurred.
3224 // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
3225 pub fn resolve_str_path_error(
3231 ) -> Result<(ast::Path, Res), ()> {
3232 let path = if path_str.starts_with("::") {
3235 segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
3236 .chain(path_str.split("::").skip(1).map(Ident::from_str))
3237 .map(|i| self.new_ast_path_segment(i))
3246 .map(Ident::from_str)
3247 .map(|i| self.new_ast_path_segment(i))
3252 let module = self.get_module(module_id);
3253 let parent_scope = &ParentScope::module(module, self);
3254 let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
3258 // Resolve a path passed from rustdoc or HIR lowering.
3259 fn resolve_ast_path(
3263 parent_scope: &ParentScope<'a>,
3264 ) -> Result<Res, (Span, ResolutionError<'a>)> {
3265 match self.resolve_path(
3266 &Segment::from_path(path),
3273 PathResult::Module(ModuleOrUniformRoot::Module(module)) => Ok(module.res().unwrap()),
3274 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
3275 Ok(path_res.base_res())
3277 PathResult::NonModule(..) => Err((
3279 ResolutionError::FailedToResolve {
3280 label: String::from("type-relative paths are not supported in this context"),
3284 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
3285 PathResult::Failed { span, label, suggestion, .. } => {
3286 Err((span, ResolutionError::FailedToResolve { label, suggestion }))
3291 fn new_ast_path_segment(&mut self, ident: Ident) -> ast::PathSegment {
3292 let mut seg = ast::PathSegment::from_ident(ident);
3293 seg.id = self.next_node_id();
3298 pub fn graph_root(&self) -> Module<'a> {
3303 pub fn all_macros(&self) -> &FxHashMap<Symbol, Res> {
3307 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
3309 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
3310 if let Some(def_id) = def_id.as_local() { Some(self.def_id_to_span[def_id]) } else { None }
3313 /// Checks if an expression refers to a function marked with
3314 /// `#[rustc_legacy_const_generics]` and returns the argument index list
3315 /// from the attribute.
3316 pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
3317 if let ExprKind::Path(None, path) = &expr.kind {
3318 // Don't perform legacy const generics rewriting if the path already
3319 // has generic arguments.
3320 if path.segments.last().unwrap().args.is_some() {
3324 let partial_res = self.partial_res_map.get(&expr.id)?;
3325 if partial_res.unresolved_segments() != 0 {
3329 if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_res() {
3330 // We only support cross-crate argument rewriting. Uses
3331 // within the same crate should be updated to use the new
3332 // const generics style.
3333 if def_id.is_local() {
3337 if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
3341 let parse_attrs = || {
3342 let attrs = self.cstore().item_attrs(def_id, self.session);
3345 .find(|a| self.session.check_name(a, sym::rustc_legacy_const_generics))?;
3346 let mut ret = vec![];
3347 for meta in attr.meta_item_list()? {
3348 match meta.literal()?.kind {
3349 LitKind::Int(a, _) => {
3350 ret.push(a as usize);
3352 _ => panic!("invalid arg index"),
3358 // Cache the lookup to avoid parsing attributes for an iterm
3360 let ret = parse_attrs();
3361 self.legacy_const_generic_args.insert(def_id, ret.clone());
3368 fn resolve_main(&mut self) {
3369 let module = self.graph_root;
3370 let ident = Ident::with_dummy_span(sym::main);
3371 let parent_scope = &ParentScope::module(module, self);
3373 let name_binding = match self.resolve_ident_in_module(
3374 ModuleOrUniformRoot::Module(module),
3381 Ok(name_binding) => name_binding,
3385 let res = name_binding.res();
3386 let is_import = name_binding.is_import();
3387 let span = name_binding.span;
3388 if let Res::Def(DefKind::Fn, _) = res {
3389 self.record_use(ident, ValueNS, name_binding, false);
3391 self.main_def = Some(MainDefinition { res, is_import, span });
3395 fn names_to_string(names: &[Symbol]) -> String {
3396 let mut result = String::new();
3397 for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() {
3399 result.push_str("::");
3401 if Ident::with_dummy_span(*name).is_raw_guess() {
3402 result.push_str("r#");
3404 result.push_str(&name.as_str());
3409 fn path_names_to_string(path: &Path) -> String {
3410 names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>())
3413 /// A somewhat inefficient routine to obtain the name of a module.
3414 fn module_to_string(module: Module<'_>) -> Option<String> {
3415 let mut names = Vec::new();
3417 fn collect_mod(names: &mut Vec<Symbol>, module: Module<'_>) {
3418 if let ModuleKind::Def(.., name) = module.kind {
3419 if let Some(parent) = module.parent {
3421 collect_mod(names, parent);
3424 names.push(Symbol::intern("<opaque>"));
3425 collect_mod(names, module.parent.unwrap());
3428 collect_mod(&mut names, module);
3430 if names.is_empty() {
3434 Some(names_to_string(&names))
3437 #[derive(Copy, Clone, Debug)]
3439 /// Do not issue the lint.
3442 /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
3443 /// In this case, we can take the span of that path.
3446 /// This lint comes from a `use` statement. In this case, what we
3447 /// care about really is the *root* `use` statement; e.g., if we
3448 /// have nested things like `use a::{b, c}`, we care about the
3450 UsePath { root_id: NodeId, root_span: Span },
3452 /// This is the "trait item" from a fully qualified path. For example,
3453 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
3454 /// The `path_span` is the span of the to the trait itself (`X::Y`).
3455 QPathTrait { qpath_id: NodeId, qpath_span: Span },
3459 fn node_id(&self) -> Option<NodeId> {
3461 CrateLint::No => None,
3462 CrateLint::SimplePath(id)
3463 | CrateLint::UsePath { root_id: id, .. }
3464 | CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
3469 pub fn provide(providers: &mut Providers) {
3470 late::lifetimes::provide(providers);