//! This crate is responsible for the part of name resolution that doesn't require type checker. //! //! Module structure of the crate is built here. //! Paths in macros, imports, expressions, types, patterns are resolved here. //! Label and lifetime names are resolved here as well. //! //! Type-relative name resolution (methods, fields, associated items) happens in `rustc_hir_analysis`. #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")] #![feature(assert_matches)] #![feature(box_patterns)] #![feature(drain_filter)] #![feature(if_let_guard)] #![feature(iter_intersperse)] #![feature(let_chains)] #![feature(never_type)] #![recursion_limit = "256"] #![allow(rustdoc::private_intra_doc_links)] #![allow(rustc::potential_query_instability)] #[macro_use] extern crate tracing; use rustc_arena::{DroplessArena, TypedArena}; use rustc_ast::node_id::NodeMap; use rustc_ast::{self as ast, NodeId, CRATE_NODE_ID}; use rustc_ast::{AngleBracketedArg, Crate, Expr, ExprKind, GenericArg, GenericArgs, LitKind, Path}; use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet}; use rustc_data_structures::intern::Interned; use rustc_data_structures::sync::{Lrc, MappedReadGuard}; use rustc_errors::{ Applicability, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, SubdiagnosticMessage, }; use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind}; use rustc_hir::def::Namespace::{self, *}; use rustc_hir::def::{self, CtorOf, DefKind, DocLinkResMap, LifetimeRes, PartialRes, PerNS}; use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId}; use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE}; use rustc_hir::definitions::DefPathData; use rustc_hir::TraitCandidate; use rustc_index::vec::IndexVec; use rustc_macros::fluent_messages; use rustc_metadata::creader::{CStore, CrateLoader}; use rustc_middle::metadata::ModChild; use rustc_middle::middle::privacy::EffectiveVisibilities; use rustc_middle::span_bug; use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, TyCtxt}; use rustc_middle::ty::{ResolverGlobalCtxt, ResolverOutputs}; use rustc_query_system::ich::StableHashingContext; use rustc_session::cstore::CrateStore; use rustc_session::lint::LintBuffer; use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind, SyntaxContext, Transparency}; use rustc_span::source_map::Spanned; use rustc_span::symbol::{kw, sym, Ident, Symbol}; use rustc_span::{Span, DUMMY_SP}; use smallvec::{smallvec, SmallVec}; use std::cell::{Cell, RefCell}; use std::collections::BTreeSet; use std::{fmt, ptr}; use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion}; use imports::{Import, ImportKind, NameResolution}; use late::{HasGenericParams, PathSource, PatternSource}; use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef}; use crate::effective_visibilities::EffectiveVisibilitiesVisitor; type Res = def::Res; mod build_reduced_graph; mod check_unused; mod def_collector; mod diagnostics; mod effective_visibilities; mod errors; mod ident; mod imports; mod late; mod macros; pub mod rustdoc; fluent_messages! { "../locales/en-US.ftl" } enum Weak { Yes, No, } #[derive(Copy, Clone, PartialEq, Debug)] enum Determinacy { Determined, Undetermined, } impl Determinacy { fn determined(determined: bool) -> Determinacy { if determined { Determinacy::Determined } else { Determinacy::Undetermined } } } /// A specific scope in which a name can be looked up. /// This enum is currently used only for early resolution (imports and macros), /// but not for late resolution yet. #[derive(Clone, Copy)] enum Scope<'a> { DeriveHelpers(LocalExpnId), DeriveHelpersCompat, MacroRules(MacroRulesScopeRef<'a>), CrateRoot, // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK` // lint if it should be reported. Module(Module<'a>, Option), MacroUsePrelude, BuiltinAttrs, ExternPrelude, ToolPrelude, StdLibPrelude, BuiltinTypes, } /// Names from different contexts may want to visit different subsets of all specific scopes /// with different restrictions when looking up the resolution. /// This enum is currently used only for early resolution (imports and macros), /// but not for late resolution yet. #[derive(Clone, Copy)] enum ScopeSet<'a> { /// All scopes with the given namespace. All(Namespace, /*is_import*/ bool), /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros). AbsolutePath(Namespace), /// All scopes with macro namespace and the given macro kind restriction. Macro(MacroKind), /// All scopes with the given namespace, used for partially performing late resolution. /// The node id enables lints and is used for reporting them. Late(Namespace, Module<'a>, Option), } /// Everything you need to know about a name's location to resolve it. /// Serves as a starting point for the scope visitor. /// This struct is currently used only for early resolution (imports and macros), /// but not for late resolution yet. #[derive(Clone, Copy, Debug)] struct ParentScope<'a> { module: Module<'a>, expansion: LocalExpnId, macro_rules: MacroRulesScopeRef<'a>, derives: &'a [ast::Path], } impl<'a> ParentScope<'a> { /// Creates a parent scope with the passed argument used as the module scope component, /// and other scope components set to default empty values. fn module(module: Module<'a>, resolver: &Resolver<'a, '_>) -> ParentScope<'a> { ParentScope { module, expansion: LocalExpnId::ROOT, macro_rules: resolver.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty), derives: &[], } } } #[derive(Copy, Debug, Clone)] enum ImplTraitContext { Existential, Universal(LocalDefId), } struct BindingError { name: Symbol, origin: BTreeSet, target: BTreeSet, could_be_path: bool, } enum ResolutionError<'a> { /// Error E0401: can't use type or const parameters from outer function. GenericParamsFromOuterFunction(Res, HasGenericParams), /// Error E0403: the name is already used for a type or const parameter in this generic /// parameter list. NameAlreadyUsedInParameterList(Symbol, Span), /// Error E0407: method is not a member of trait. MethodNotMemberOfTrait(Ident, String, Option), /// Error E0437: type is not a member of trait. TypeNotMemberOfTrait(Ident, String, Option), /// Error E0438: const is not a member of trait. ConstNotMemberOfTrait(Ident, String, Option), /// Error E0408: variable `{}` is not bound in all patterns. VariableNotBoundInPattern(BindingError, ParentScope<'a>), /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm. VariableBoundWithDifferentMode(Symbol, Span), /// Error E0415: identifier is bound more than once in this parameter list. IdentifierBoundMoreThanOnceInParameterList(Symbol), /// Error E0416: identifier is bound more than once in the same pattern. IdentifierBoundMoreThanOnceInSamePattern(Symbol), /// Error E0426: use of undeclared label. UndeclaredLabel { name: Symbol, suggestion: Option }, /// Error E0429: `self` imports are only allowed within a `{ }` list. SelfImportsOnlyAllowedWithin { root: bool, span_with_rename: Span }, /// Error E0430: `self` import can only appear once in the list. SelfImportCanOnlyAppearOnceInTheList, /// Error E0431: `self` import can only appear in an import list with a non-empty prefix. SelfImportOnlyInImportListWithNonEmptyPrefix, /// Error E0433: failed to resolve. FailedToResolve { label: String, suggestion: Option }, /// Error E0434: can't capture dynamic environment in a fn item. CannotCaptureDynamicEnvironmentInFnItem, /// Error E0435: attempt to use a non-constant value in a constant. AttemptToUseNonConstantValueInConstant( Ident, /* suggestion */ &'static str, /* current */ &'static str, ), /// Error E0530: `X` bindings cannot shadow `Y`s. BindingShadowsSomethingUnacceptable { shadowing_binding: PatternSource, name: Symbol, participle: &'static str, article: &'static str, shadowed_binding: Res, shadowed_binding_span: Span, }, /// Error E0128: generic parameters with a default cannot use forward-declared identifiers. ForwardDeclaredGenericParam, /// ERROR E0770: the type of const parameters must not depend on other generic parameters. ParamInTyOfConstParam(Symbol), /// generic parameters must not be used inside const evaluations. /// /// This error is only emitted when using `min_const_generics`. ParamInNonTrivialAnonConst { name: Symbol, is_type: bool }, /// Error E0735: generic parameters with a default cannot use `Self` SelfInGenericParamDefault, /// Error E0767: use of unreachable label UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option }, /// Error E0323, E0324, E0325: mismatch between trait item and impl item. TraitImplMismatch { name: Symbol, kind: &'static str, trait_path: String, trait_item_span: Span, code: rustc_errors::DiagnosticId, }, /// Error E0201: multiple impl items for the same trait item. TraitImplDuplicate { name: Symbol, trait_item_span: Span, old_span: Span }, /// Inline asm `sym` operand must refer to a `fn` or `static`. InvalidAsmSym, } enum VisResolutionError<'a> { Relative2018(Span, &'a ast::Path), AncestorOnly(Span), FailedToResolve(Span, String, Option), ExpectedFound(Span, String, Res), Indeterminate(Span), ModuleOnly(Span), } /// A minimal representation of a path segment. We use this in resolve because we synthesize 'path /// segments' which don't have the rest of an AST or HIR `PathSegment`. #[derive(Clone, Copy, Debug)] struct Segment { ident: Ident, id: Option, /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing /// nonsensical suggestions. has_generic_args: bool, /// Signals whether this `PathSegment` has lifetime arguments. has_lifetime_args: bool, args_span: Span, } impl Segment { fn from_path(path: &Path) -> Vec { path.segments.iter().map(|s| s.into()).collect() } fn from_ident(ident: Ident) -> Segment { Segment { ident, id: None, has_generic_args: false, has_lifetime_args: false, args_span: DUMMY_SP, } } fn from_ident_and_id(ident: Ident, id: NodeId) -> Segment { Segment { ident, id: Some(id), has_generic_args: false, has_lifetime_args: false, args_span: DUMMY_SP, } } fn names_to_string(segments: &[Segment]) -> String { names_to_string(&segments.iter().map(|seg| seg.ident.name).collect::>()) } } impl<'a> From<&'a ast::PathSegment> for Segment { fn from(seg: &'a ast::PathSegment) -> Segment { let has_generic_args = seg.args.is_some(); let (args_span, has_lifetime_args) = if let Some(args) = seg.args.as_deref() { match args { GenericArgs::AngleBracketed(args) => { let found_lifetimes = args .args .iter() .any(|arg| matches!(arg, AngleBracketedArg::Arg(GenericArg::Lifetime(_)))); (args.span, found_lifetimes) } GenericArgs::Parenthesized(args) => (args.span, true), } } else { (DUMMY_SP, false) }; Segment { ident: seg.ident, id: Some(seg.id), has_generic_args, has_lifetime_args, args_span, } } } /// An intermediate resolution result. /// /// This refers to the thing referred by a name. The difference between `Res` and `Item` is that /// items are visible in their whole block, while `Res`es only from the place they are defined /// forward. #[derive(Debug)] enum LexicalScopeBinding<'a> { Item(&'a NameBinding<'a>), Res(Res), } impl<'a> LexicalScopeBinding<'a> { fn res(self) -> Res { match self { LexicalScopeBinding::Item(binding) => binding.res(), LexicalScopeBinding::Res(res) => res, } } } #[derive(Copy, Clone, Debug)] enum ModuleOrUniformRoot<'a> { /// Regular module. Module(Module<'a>), /// Virtual module that denotes resolution in crate root with fallback to extern prelude. CrateRootAndExternPrelude, /// Virtual module that denotes resolution in extern prelude. /// Used for paths starting with `::` on 2018 edition. ExternPrelude, /// Virtual module that denotes resolution in current scope. /// Used only for resolving single-segment imports. The reason it exists is that import paths /// are always split into two parts, the first of which should be some kind of module. CurrentScope, } impl ModuleOrUniformRoot<'_> { fn same_def(lhs: Self, rhs: Self) -> bool { match (lhs, rhs) { (ModuleOrUniformRoot::Module(lhs), ModuleOrUniformRoot::Module(rhs)) => { ptr::eq(lhs, rhs) } ( ModuleOrUniformRoot::CrateRootAndExternPrelude, ModuleOrUniformRoot::CrateRootAndExternPrelude, ) | (ModuleOrUniformRoot::ExternPrelude, ModuleOrUniformRoot::ExternPrelude) | (ModuleOrUniformRoot::CurrentScope, ModuleOrUniformRoot::CurrentScope) => true, _ => false, } } } #[derive(Debug)] enum PathResult<'a> { Module(ModuleOrUniformRoot<'a>), NonModule(PartialRes), Indeterminate, Failed { span: Span, label: String, suggestion: Option, is_error_from_last_segment: bool, }, } impl<'a> PathResult<'a> { fn failed( span: Span, is_error_from_last_segment: bool, finalize: bool, label_and_suggestion: impl FnOnce() -> (String, Option), ) -> PathResult<'a> { let (label, suggestion) = if finalize { label_and_suggestion() } else { (String::new(), None) }; PathResult::Failed { span, label, suggestion, is_error_from_last_segment } } } #[derive(Debug)] enum ModuleKind { /// An anonymous module; e.g., just a block. /// /// ``` /// fn main() { /// fn f() {} // (1) /// { // This is an anonymous module /// f(); // This resolves to (2) as we are inside the block. /// fn f() {} // (2) /// } /// f(); // Resolves to (1) /// } /// ``` Block, /// Any module with a name. /// /// This could be: /// /// * A normal module – either `mod from_file;` or `mod from_block { }` – /// or the crate root (which is conceptually a top-level module). /// Note that the crate root's [name][Self::name] will be [`kw::Empty`]. /// * A trait or an enum (it implicitly contains associated types, methods and variant /// constructors). Def(DefKind, DefId, Symbol), } impl ModuleKind { /// Get name of the module. fn name(&self) -> Option { match self { ModuleKind::Block => None, ModuleKind::Def(.., name) => Some(*name), } } } /// A key that identifies a binding in a given `Module`. /// /// Multiple bindings in the same module can have the same key (in a valid /// program) if all but one of them come from glob imports. #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)] struct BindingKey { /// The identifier for the binding, always the `normalize_to_macros_2_0` version of the /// identifier. ident: Ident, ns: Namespace, /// 0 if ident is not `_`, otherwise a value that's unique to the specific /// `_` in the expanded AST that introduced this binding. disambiguator: u32, } type Resolutions<'a> = RefCell>>>; /// One node in the tree of modules. /// /// Note that a "module" in resolve is broader than a `mod` that you declare in Rust code. It may be one of these: /// /// * `mod` /// * crate root (aka, top-level anonymous module) /// * `enum` /// * `trait` /// * curly-braced block with statements /// /// You can use [`ModuleData::kind`] to determine the kind of module this is. struct ModuleData<'a> { /// The direct parent module (it may not be a `mod`, however). parent: Option>, /// What kind of module this is, because this may not be a `mod`. kind: ModuleKind, /// Mapping between names and their (possibly in-progress) resolutions in this module. /// Resolutions in modules from other crates are not populated until accessed. lazy_resolutions: Resolutions<'a>, /// True if this is a module from other crate that needs to be populated on access. populate_on_access: Cell, /// Macro invocations that can expand into items in this module. unexpanded_invocations: RefCell>, /// Whether `#[no_implicit_prelude]` is active. no_implicit_prelude: bool, glob_importers: RefCell>>, globs: RefCell>>, /// Used to memoize the traits in this module for faster searches through all traits in scope. traits: RefCell)]>>>, /// Span of the module itself. Used for error reporting. span: Span, expansion: ExpnId, } type Module<'a> = &'a ModuleData<'a>; impl<'a> ModuleData<'a> { fn new( parent: Option>, kind: ModuleKind, expansion: ExpnId, span: Span, no_implicit_prelude: bool, ) -> Self { let is_foreign = match kind { ModuleKind::Def(_, def_id, _) => !def_id.is_local(), ModuleKind::Block => false, }; ModuleData { parent, kind, lazy_resolutions: Default::default(), populate_on_access: Cell::new(is_foreign), unexpanded_invocations: Default::default(), no_implicit_prelude, glob_importers: RefCell::new(Vec::new()), globs: RefCell::new(Vec::new()), traits: RefCell::new(None), span, expansion, } } fn for_each_child<'tcx, R, F>(&'a self, resolver: &mut R, mut f: F) where R: AsMut>, F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>), { for (key, name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() { if let Some(binding) = name_resolution.borrow().binding { f(resolver, key.ident, key.ns, binding); } } } /// This modifies `self` in place. The traits will be stored in `self.traits`. fn ensure_traits<'tcx, R>(&'a self, resolver: &mut R) where R: AsMut>, { let mut traits = self.traits.borrow_mut(); if traits.is_none() { let mut collected_traits = Vec::new(); self.for_each_child(resolver, |_, name, ns, binding| { if ns != TypeNS { return; } if let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = binding.res() { collected_traits.push((name, binding)) } }); *traits = Some(collected_traits.into_boxed_slice()); } } fn res(&self) -> Option { match self.kind { ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)), _ => None, } } // Public for rustdoc. fn def_id(&self) -> DefId { self.opt_def_id().expect("`ModuleData::def_id` is called on a block module") } fn opt_def_id(&self) -> Option { match self.kind { ModuleKind::Def(_, def_id, _) => Some(def_id), _ => None, } } // `self` resolves to the first module ancestor that `is_normal`. fn is_normal(&self) -> bool { matches!(self.kind, ModuleKind::Def(DefKind::Mod, _, _)) } fn is_trait(&self) -> bool { matches!(self.kind, ModuleKind::Def(DefKind::Trait, _, _)) } fn nearest_item_scope(&'a self) -> Module<'a> { match self.kind { ModuleKind::Def(DefKind::Enum | DefKind::Trait, ..) => { self.parent.expect("enum or trait module without a parent") } _ => self, } } /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module). /// This may be the crate root. fn nearest_parent_mod(&self) -> DefId { match self.kind { ModuleKind::Def(DefKind::Mod, def_id, _) => def_id, _ => self.parent.expect("non-root module without parent").nearest_parent_mod(), } } fn is_ancestor_of(&self, mut other: &Self) -> bool { while !ptr::eq(self, other) { if let Some(parent) = other.parent { other = parent; } else { return false; } } true } } impl<'a> fmt::Debug for ModuleData<'a> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{:?}", self.res()) } } /// Records a possibly-private value, type, or module definition. #[derive(Clone, Debug)] struct NameBinding<'a> { kind: NameBindingKind<'a>, ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>, expansion: LocalExpnId, span: Span, vis: ty::Visibility, } trait ToNameBinding<'a> { fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>; } impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> { fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> { self } } #[derive(Clone, Debug)] enum NameBindingKind<'a> { Res(Res), Module(Module<'a>), Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell }, } impl<'a> NameBindingKind<'a> { /// Is this a name binding of an import? fn is_import(&self) -> bool { matches!(*self, NameBindingKind::Import { .. }) } } struct PrivacyError<'a> { ident: Ident, binding: &'a NameBinding<'a>, dedup_span: Span, } struct UseError<'a> { err: DiagnosticBuilder<'a, ErrorGuaranteed>, /// Candidates which user could `use` to access the missing type. candidates: Vec, /// The `DefId` of the module to place the use-statements in. def_id: DefId, /// Whether the diagnostic should say "instead" (as in `consider importing ... instead`). instead: bool, /// Extra free-form suggestion. suggestion: Option<(Span, &'static str, String, Applicability)>, /// Path `Segment`s at the place of use that failed. Used for accurate suggestion after telling /// the user to import the item directly. path: Vec, /// Whether the expected source is a call is_call: bool, } #[derive(Clone, Copy, PartialEq, Debug)] enum AmbiguityKind { Import, BuiltinAttr, DeriveHelper, MacroRulesVsModularized, GlobVsOuter, GlobVsGlob, GlobVsExpanded, MoreExpandedVsOuter, } impl AmbiguityKind { fn descr(self) -> &'static str { match self { AmbiguityKind::Import => "multiple potential import sources", AmbiguityKind::BuiltinAttr => "a name conflict with a builtin attribute", AmbiguityKind::DeriveHelper => "a name conflict with a derive helper attribute", AmbiguityKind::MacroRulesVsModularized => { "a conflict between a `macro_rules` name and a non-`macro_rules` name from another module" } AmbiguityKind::GlobVsOuter => { "a conflict between a name from a glob import and an outer scope during import or macro resolution" } AmbiguityKind::GlobVsGlob => "multiple glob imports of a name in the same module", AmbiguityKind::GlobVsExpanded => { "a conflict between a name from a glob import and a macro-expanded name in the same module during import or macro resolution" } AmbiguityKind::MoreExpandedVsOuter => { "a conflict between a macro-expanded name and a less macro-expanded name from outer scope during import or macro resolution" } } } } /// Miscellaneous bits of metadata for better ambiguity error reporting. #[derive(Clone, Copy, PartialEq)] enum AmbiguityErrorMisc { SuggestCrate, SuggestSelf, FromPrelude, None, } struct AmbiguityError<'a> { kind: AmbiguityKind, ident: Ident, b1: &'a NameBinding<'a>, b2: &'a NameBinding<'a>, misc1: AmbiguityErrorMisc, misc2: AmbiguityErrorMisc, } impl<'a> NameBinding<'a> { fn module(&self) -> Option> { match self.kind { NameBindingKind::Module(module) => Some(module), NameBindingKind::Import { binding, .. } => binding.module(), _ => None, } } fn res(&self) -> Res { match self.kind { NameBindingKind::Res(res) => res, NameBindingKind::Module(module) => module.res().unwrap(), NameBindingKind::Import { binding, .. } => binding.res(), } } fn is_ambiguity(&self) -> bool { self.ambiguity.is_some() || match self.kind { NameBindingKind::Import { binding, .. } => binding.is_ambiguity(), _ => false, } } fn is_possibly_imported_variant(&self) -> bool { match self.kind { NameBindingKind::Import { binding, .. } => binding.is_possibly_imported_variant(), NameBindingKind::Res(Res::Def( DefKind::Variant | DefKind::Ctor(CtorOf::Variant, ..), _, )) => true, NameBindingKind::Res(..) | NameBindingKind::Module(..) => false, } } fn is_extern_crate(&self) -> bool { match self.kind { NameBindingKind::Import { import: &Import { kind: ImportKind::ExternCrate { .. }, .. }, .. } => true, NameBindingKind::Module(&ModuleData { kind: ModuleKind::Def(DefKind::Mod, def_id, _), .. }) => def_id.is_crate_root(), _ => false, } } fn is_import(&self) -> bool { matches!(self.kind, NameBindingKind::Import { .. }) } /// The binding introduced by `#[macro_export] macro_rules` is a public import, but it might /// not be perceived as such by users, so treat it as a non-import in some diagnostics. fn is_import_user_facing(&self) -> bool { matches!(self.kind, NameBindingKind::Import { import, .. } if !matches!(import.kind, ImportKind::MacroExport)) } fn is_glob_import(&self) -> bool { match self.kind { NameBindingKind::Import { import, .. } => import.is_glob(), _ => false, } } fn is_importable(&self) -> bool { !matches!( self.res(), Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _) ) } fn macro_kind(&self) -> Option { self.res().macro_kind() } // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding` // at some expansion round `max(invoc, binding)` when they both emerged from macros. // Then this function returns `true` if `self` may emerge from a macro *after* that // in some later round and screw up our previously found resolution. // See more detailed explanation in // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049 fn may_appear_after( &self, invoc_parent_expansion: LocalExpnId, binding: &NameBinding<'_>, ) -> bool { // self > max(invoc, binding) => !(self <= invoc || self <= binding) // Expansions are partially ordered, so "may appear after" is an inversion of // "certainly appears before or simultaneously" and includes unordered cases. let self_parent_expansion = self.expansion; let other_parent_expansion = binding.expansion; let certainly_before_other_or_simultaneously = other_parent_expansion.is_descendant_of(self_parent_expansion); let certainly_before_invoc_or_simultaneously = invoc_parent_expansion.is_descendant_of(self_parent_expansion); !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously) } } #[derive(Default, Clone)] struct ExternPreludeEntry<'a> { extern_crate_item: Option<&'a NameBinding<'a>>, introduced_by_item: bool, } /// Used for better errors for E0773 enum BuiltinMacroState { NotYetSeen(SyntaxExtensionKind), AlreadySeen(Span), } struct DeriveData { resolutions: DeriveResolutions, helper_attrs: Vec<(usize, Ident)>, has_derive_copy: bool, } #[derive(Clone)] struct MacroData { ext: Lrc, macro_rules: bool, } /// The main resolver class. /// /// This is the visitor that walks the whole crate. pub struct Resolver<'a, 'tcx> { tcx: TyCtxt<'tcx>, /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`. expn_that_defined: FxHashMap, graph_root: Module<'a>, prelude: Option>, extern_prelude: FxHashMap>, /// N.B., this is used only for better diagnostics, not name resolution itself. has_self: FxHashSet, /// Names of fields of an item `DefId` accessible with dot syntax. /// Used for hints during error reporting. field_names: FxHashMap>>, /// Span of the privacy modifier in fields of an item `DefId` accessible with dot syntax. /// Used for hints during error reporting. field_visibility_spans: FxHashMap>, /// All imports known to succeed or fail. determined_imports: Vec<&'a Import<'a>>, /// All non-determined imports. indeterminate_imports: Vec<&'a Import<'a>>, // Spans for local variables found during pattern resolution. // Used for suggestions during error reporting. pat_span_map: NodeMap, /// Resolutions for nodes that have a single resolution. partial_res_map: NodeMap, /// Resolutions for import nodes, which have multiple resolutions in different namespaces. import_res_map: NodeMap>>, /// Resolutions for labels (node IDs of their corresponding blocks or loops). label_res_map: NodeMap, /// Resolutions for lifetimes. lifetimes_res_map: NodeMap, /// Lifetime parameters that lowering will have to introduce. extra_lifetime_params_map: NodeMap>, /// `CrateNum` resolutions of `extern crate` items. extern_crate_map: FxHashMap, reexport_map: FxHashMap>, trait_map: NodeMap>, /// A map from nodes to anonymous modules. /// Anonymous modules are pseudo-modules that are implicitly created around items /// contained within blocks. /// /// For example, if we have this: /// /// fn f() { /// fn g() { /// ... /// } /// } /// /// There will be an anonymous module created around `g` with the ID of the /// entry block for `f`. block_map: NodeMap>, /// A fake module that contains no definition and no prelude. Used so that /// some AST passes can generate identifiers that only resolve to local or /// language items. empty_module: Module<'a>, module_map: FxHashMap>, binding_parent_modules: FxHashMap>, Module<'a>>, underscore_disambiguator: u32, /// Maps glob imports to the names of items actually imported. glob_map: FxHashMap>, /// Visibilities in "lowered" form, for all entities that have them. visibilities: FxHashMap, has_pub_restricted: bool, used_imports: FxHashSet, maybe_unused_trait_imports: FxIndexSet, /// Privacy errors are delayed until the end in order to deduplicate them. privacy_errors: Vec>, /// Ambiguity errors are delayed for deduplication. ambiguity_errors: Vec>, /// `use` injections are delayed for better placement and deduplication. use_injections: Vec>, /// Crate-local macro expanded `macro_export` referred to by a module-relative path. macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>, arenas: &'a ResolverArenas<'a>, dummy_binding: &'a NameBinding<'a>, used_extern_options: FxHashSet, macro_names: FxHashSet, builtin_macros: FxHashMap, /// A small map keeping true kinds of built-in macros that appear to be fn-like on /// the surface (`macro` items in libcore), but are actually attributes or derives. builtin_macro_kinds: FxHashMap, registered_tools: RegisteredTools, macro_use_prelude: FxHashMap>, macro_map: FxHashMap, dummy_ext_bang: Lrc, dummy_ext_derive: Lrc, non_macro_attr: Lrc, local_macro_def_scopes: FxHashMap>, ast_transform_scopes: FxHashMap>, unused_macros: FxHashMap, unused_macro_rules: FxHashMap<(LocalDefId, usize), (Ident, Span)>, proc_macro_stubs: FxHashSet, /// Traces collected during macro resolution and validated when it's complete. single_segment_macro_resolutions: Vec<(Ident, MacroKind, ParentScope<'a>, Option<&'a NameBinding<'a>>)>, multi_segment_macro_resolutions: Vec<(Vec, Span, MacroKind, ParentScope<'a>, Option)>, builtin_attrs: Vec<(Ident, ParentScope<'a>)>, /// `derive(Copy)` marks items they are applied to so they are treated specially later. /// Derive macros cannot modify the item themselves and have to store the markers in the global /// context, so they attach the markers to derive container IDs using this resolver table. containers_deriving_copy: FxHashSet, /// Parent scopes in which the macros were invoked. /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere. invocation_parent_scopes: FxHashMap>, /// `macro_rules` scopes *produced* by expanding the macro invocations, /// include all the `macro_rules` items and other invocations generated by them. output_macro_rules_scopes: FxHashMap>, /// `macro_rules` scopes produced by `macro_rules` item definitions. macro_rules_scopes: FxHashMap>, /// Helper attributes that are in scope for the given expansion. helper_attrs: FxHashMap>, /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute /// with the given `ExpnId`. derive_data: FxHashMap, /// Avoid duplicated errors for "name already defined". name_already_seen: FxHashMap, potentially_unused_imports: Vec<&'a Import<'a>>, /// Table for mapping struct IDs into struct constructor IDs, /// it's not used during normal resolution, only for better error reporting. /// Also includes of list of each fields visibility struct_constructors: DefIdMap<(Res, ty::Visibility, Vec>)>, /// Features enabled for this crate. active_features: FxHashSet, lint_buffer: LintBuffer, next_node_id: NodeId, node_id_to_def_id: FxHashMap, def_id_to_node_id: IndexVec, /// Indices of unnamed struct or variant fields with unresolved attributes. placeholder_field_indices: FxHashMap, /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId` /// we know what parent node that fragment should be attached to thanks to this table, /// and how the `impl Trait` fragments were introduced. invocation_parents: FxHashMap, /// Some way to know that we are in a *trait* impl in `visit_assoc_item`. /// FIXME: Replace with a more general AST map (together with some other fields). trait_impl_items: FxHashSet, legacy_const_generic_args: FxHashMap>>, /// Amount of lifetime parameters for each item in the crate. item_generics_num_lifetimes: FxHashMap, main_def: Option, trait_impls: FxIndexMap>, /// A list of proc macro LocalDefIds, written out in the order in which /// they are declared in the static array generated by proc_macro_harness. proc_macros: Vec, confused_type_with_std_module: FxHashMap, /// Whether lifetime elision was successful. lifetime_elision_allowed: FxHashSet, effective_visibilities: EffectiveVisibilities, doc_link_resolutions: FxHashMap, doc_link_traits_in_scope: FxHashMap>, all_macro_rules: FxHashMap, } /// Nothing really interesting here; it just provides memory for the rest of the crate. #[derive(Default)] pub struct ResolverArenas<'a> { modules: TypedArena>, local_modules: RefCell>>, imports: TypedArena>, name_resolutions: TypedArena>>, ast_paths: TypedArena, dropless: DroplessArena, } impl<'a> ResolverArenas<'a> { fn new_module( &'a self, parent: Option>, kind: ModuleKind, expn_id: ExpnId, span: Span, no_implicit_prelude: bool, module_map: &mut FxHashMap>, ) -> Module<'a> { let module = self.modules.alloc(ModuleData::new(parent, kind, expn_id, span, no_implicit_prelude)); let def_id = module.opt_def_id(); if def_id.map_or(true, |def_id| def_id.is_local()) { self.local_modules.borrow_mut().push(module); } if let Some(def_id) = def_id { module_map.insert(def_id, module); } module } fn local_modules(&'a self) -> std::cell::Ref<'a, Vec>> { self.local_modules.borrow() } fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> { self.dropless.alloc(name_binding) } fn alloc_import(&'a self, import: Import<'a>) -> &'a Import<'_> { self.imports.alloc(import) } fn alloc_name_resolution(&'a self) -> &'a RefCell> { self.name_resolutions.alloc(Default::default()) } fn alloc_macro_rules_scope(&'a self, scope: MacroRulesScope<'a>) -> MacroRulesScopeRef<'a> { Interned::new_unchecked(self.dropless.alloc(Cell::new(scope))) } fn alloc_macro_rules_binding( &'a self, binding: MacroRulesBinding<'a>, ) -> &'a MacroRulesBinding<'a> { self.dropless.alloc(binding) } fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] { self.ast_paths.alloc_from_iter(paths.iter().cloned()) } fn alloc_pattern_spans(&'a self, spans: impl Iterator) -> &'a [Span] { self.dropless.alloc_from_iter(spans) } } impl<'a, 'tcx> AsMut> for Resolver<'a, 'tcx> { fn as_mut(&mut self) -> &mut Resolver<'a, 'tcx> { self } } impl<'a, 'b, 'tcx> DefIdTree for &'a Resolver<'b, 'tcx> { #[inline] fn opt_parent(self, id: DefId) -> Option { self.tcx.opt_parent(id) } } impl<'tcx> Resolver<'_, 'tcx> { fn opt_local_def_id(&self, node: NodeId) -> Option { self.node_id_to_def_id.get(&node).copied() } fn local_def_id(&self, node: NodeId) -> LocalDefId { self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node)) } /// Adds a definition with a parent definition. fn create_def( &mut self, parent: LocalDefId, node_id: ast::NodeId, data: DefPathData, expn_id: ExpnId, span: Span, ) -> LocalDefId { assert!( !self.node_id_to_def_id.contains_key(&node_id), "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}", node_id, data, self.tcx.definitions_untracked().def_key(self.node_id_to_def_id[&node_id]), ); // FIXME: remove `def_span` body, pass in the right spans here and call `tcx.at().create_def()` let def_id = self.tcx.untracked().definitions.write().create_def(parent, data); // Create the definition. if expn_id != ExpnId::root() { self.expn_that_defined.insert(def_id, expn_id); } // A relative span's parent must be an absolute span. debug_assert_eq!(span.data_untracked().parent, None); let _id = self.tcx.untracked().source_span.push(span); debug_assert_eq!(_id, def_id); // Some things for which we allocate `LocalDefId`s don't correspond to // anything in the AST, so they don't have a `NodeId`. For these cases // we don't need a mapping from `NodeId` to `LocalDefId`. if node_id != ast::DUMMY_NODE_ID { debug!("create_def: def_id_to_node_id[{:?}] <-> {:?}", def_id, node_id); self.node_id_to_def_id.insert(node_id, def_id); } assert_eq!(self.def_id_to_node_id.push(node_id), def_id); def_id } fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize { if let Some(def_id) = def_id.as_local() { self.item_generics_num_lifetimes[&def_id] } else { self.cstore().item_generics_num_lifetimes(def_id, self.tcx.sess) } } pub fn tcx(&self) -> TyCtxt<'tcx> { self.tcx } } impl<'a, 'tcx> Resolver<'a, 'tcx> { pub fn new( tcx: TyCtxt<'tcx>, krate: &Crate, arenas: &'a ResolverArenas<'a>, ) -> Resolver<'a, 'tcx> { let root_def_id = CRATE_DEF_ID.to_def_id(); let mut module_map = FxHashMap::default(); let graph_root = arenas.new_module( None, ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty), ExpnId::root(), krate.spans.inner_span, tcx.sess.contains_name(&krate.attrs, sym::no_implicit_prelude), &mut module_map, ); let empty_module = arenas.new_module( None, ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty), ExpnId::root(), DUMMY_SP, true, &mut FxHashMap::default(), ); let mut visibilities = FxHashMap::default(); visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public); let mut def_id_to_node_id = IndexVec::default(); assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), CRATE_DEF_ID); let mut node_id_to_def_id = FxHashMap::default(); node_id_to_def_id.insert(CRATE_NODE_ID, CRATE_DEF_ID); let mut invocation_parents = FxHashMap::default(); invocation_parents.insert(LocalExpnId::ROOT, (CRATE_DEF_ID, ImplTraitContext::Existential)); let mut extern_prelude: FxHashMap> = tcx .sess .opts .externs .iter() .filter(|(_, entry)| entry.add_prelude) .map(|(name, _)| (Ident::from_str(name), Default::default())) .collect(); if !tcx.sess.contains_name(&krate.attrs, sym::no_core) { extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default()); if !tcx.sess.contains_name(&krate.attrs, sym::no_std) { extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default()); } } let registered_tools = macros::registered_tools(tcx.sess, &krate.attrs); let features = tcx.sess.features_untracked(); let mut resolver = Resolver { tcx, expn_that_defined: Default::default(), // The outermost module has def ID 0; this is not reflected in the // AST. graph_root, prelude: None, extern_prelude, has_self: FxHashSet::default(), field_names: FxHashMap::default(), field_visibility_spans: FxHashMap::default(), determined_imports: Vec::new(), indeterminate_imports: Vec::new(), pat_span_map: Default::default(), partial_res_map: Default::default(), import_res_map: Default::default(), label_res_map: Default::default(), lifetimes_res_map: Default::default(), extra_lifetime_params_map: Default::default(), extern_crate_map: Default::default(), reexport_map: FxHashMap::default(), trait_map: NodeMap::default(), underscore_disambiguator: 0, empty_module, module_map, block_map: Default::default(), binding_parent_modules: FxHashMap::default(), ast_transform_scopes: FxHashMap::default(), glob_map: Default::default(), visibilities, has_pub_restricted: false, used_imports: FxHashSet::default(), maybe_unused_trait_imports: Default::default(), privacy_errors: Vec::new(), ambiguity_errors: Vec::new(), use_injections: Vec::new(), macro_expanded_macro_export_errors: BTreeSet::new(), arenas, dummy_binding: arenas.alloc_name_binding(NameBinding { kind: NameBindingKind::Res(Res::Err), ambiguity: None, expansion: LocalExpnId::ROOT, span: DUMMY_SP, vis: ty::Visibility::Public, }), used_extern_options: Default::default(), macro_names: FxHashSet::default(), builtin_macros: Default::default(), builtin_macro_kinds: Default::default(), registered_tools, macro_use_prelude: FxHashMap::default(), macro_map: FxHashMap::default(), dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(tcx.sess.edition())), dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(tcx.sess.edition())), non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(tcx.sess.edition())), invocation_parent_scopes: Default::default(), output_macro_rules_scopes: Default::default(), macro_rules_scopes: Default::default(), helper_attrs: Default::default(), derive_data: Default::default(), local_macro_def_scopes: FxHashMap::default(), name_already_seen: FxHashMap::default(), potentially_unused_imports: Vec::new(), struct_constructors: Default::default(), unused_macros: Default::default(), unused_macro_rules: Default::default(), proc_macro_stubs: Default::default(), single_segment_macro_resolutions: Default::default(), multi_segment_macro_resolutions: Default::default(), builtin_attrs: Default::default(), containers_deriving_copy: Default::default(), active_features: features .declared_lib_features .iter() .map(|(feat, ..)| *feat) .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat)) .collect(), lint_buffer: LintBuffer::default(), next_node_id: CRATE_NODE_ID, node_id_to_def_id, def_id_to_node_id, placeholder_field_indices: Default::default(), invocation_parents, trait_impl_items: Default::default(), legacy_const_generic_args: Default::default(), item_generics_num_lifetimes: Default::default(), main_def: Default::default(), trait_impls: Default::default(), proc_macros: Default::default(), confused_type_with_std_module: Default::default(), lifetime_elision_allowed: Default::default(), effective_visibilities: Default::default(), doc_link_resolutions: Default::default(), doc_link_traits_in_scope: Default::default(), all_macro_rules: Default::default(), }; let root_parent_scope = ParentScope::module(graph_root, &resolver); resolver.invocation_parent_scopes.insert(LocalExpnId::ROOT, root_parent_scope); resolver } fn new_module( &mut self, parent: Option>, kind: ModuleKind, expn_id: ExpnId, span: Span, no_implicit_prelude: bool, ) -> Module<'a> { let module_map = &mut self.module_map; self.arenas.new_module(parent, kind, expn_id, span, no_implicit_prelude, module_map) } fn next_node_id(&mut self) -> NodeId { let start = self.next_node_id; let next = start.as_u32().checked_add(1).expect("input too large; ran out of NodeIds"); self.next_node_id = ast::NodeId::from_u32(next); start } fn next_node_ids(&mut self, count: usize) -> std::ops::Range { let start = self.next_node_id; let end = start.as_usize().checked_add(count).expect("input too large; ran out of NodeIds"); self.next_node_id = ast::NodeId::from_usize(end); start..self.next_node_id } pub fn lint_buffer(&mut self) -> &mut LintBuffer { &mut self.lint_buffer } pub fn arenas() -> ResolverArenas<'a> { Default::default() } pub fn into_outputs(self) -> ResolverOutputs { let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect(); let expn_that_defined = self.expn_that_defined; let visibilities = self.visibilities; let has_pub_restricted = self.has_pub_restricted; let extern_crate_map = self.extern_crate_map; let reexport_map = self.reexport_map; let maybe_unused_trait_imports = self.maybe_unused_trait_imports; let glob_map = self.glob_map; let main_def = self.main_def; let confused_type_with_std_module = self.confused_type_with_std_module; let effective_visibilities = self.effective_visibilities; let global_ctxt = ResolverGlobalCtxt { expn_that_defined, visibilities, has_pub_restricted, effective_visibilities, extern_crate_map, reexport_map, glob_map, maybe_unused_trait_imports, main_def, trait_impls: self.trait_impls, proc_macros, confused_type_with_std_module, registered_tools: self.registered_tools, doc_link_resolutions: self.doc_link_resolutions, doc_link_traits_in_scope: self.doc_link_traits_in_scope, all_macro_rules: self.all_macro_rules, }; let ast_lowering = ty::ResolverAstLowering { legacy_const_generic_args: self.legacy_const_generic_args, partial_res_map: self.partial_res_map, import_res_map: self.import_res_map, label_res_map: self.label_res_map, lifetimes_res_map: self.lifetimes_res_map, extra_lifetime_params_map: self.extra_lifetime_params_map, next_node_id: self.next_node_id, node_id_to_def_id: self.node_id_to_def_id, def_id_to_node_id: self.def_id_to_node_id, trait_map: self.trait_map, builtin_macro_kinds: self.builtin_macro_kinds, lifetime_elision_allowed: self.lifetime_elision_allowed, }; ResolverOutputs { global_ctxt, ast_lowering } } fn create_stable_hashing_context(&self) -> StableHashingContext<'_> { StableHashingContext::new(self.tcx.sess, self.tcx.untracked()) } fn crate_loader(&mut self, f: impl FnOnce(&mut CrateLoader<'_, '_>) -> T) -> T { let mut cstore = self.tcx.untracked().cstore.write(); let cstore = cstore.untracked_as_any().downcast_mut().unwrap(); f(&mut CrateLoader::new(self.tcx, &mut *cstore, &mut self.used_extern_options)) } fn cstore(&self) -> MappedReadGuard<'_, CStore> { CStore::from_tcx(self.tcx) } fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc { match macro_kind { MacroKind::Bang => self.dummy_ext_bang.clone(), MacroKind::Derive => self.dummy_ext_derive.clone(), MacroKind::Attr => self.non_macro_attr.clone(), } } /// Runs the function on each namespace. fn per_ns(&mut self, mut f: F) { f(self, TypeNS); f(self, ValueNS); f(self, MacroNS); } fn is_builtin_macro(&mut self, res: Res) -> bool { self.get_macro(res).map_or(false, |macro_data| macro_data.ext.builtin_name.is_some()) } fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId { loop { match ctxt.outer_expn_data().macro_def_id { Some(def_id) => return def_id, None => ctxt.remove_mark(), }; } } /// Entry point to crate resolution. pub fn resolve_crate(&mut self, krate: &Crate) { self.tcx.sess.time("resolve_crate", || { self.tcx.sess.time("finalize_imports", || self.finalize_imports()); self.tcx.sess.time("compute_effective_visibilities", || { EffectiveVisibilitiesVisitor::compute_effective_visibilities(self, krate) }); self.tcx.sess.time("finalize_macro_resolutions", || self.finalize_macro_resolutions()); self.tcx.sess.time("late_resolve_crate", || self.late_resolve_crate(krate)); self.tcx.sess.time("resolve_main", || self.resolve_main()); self.tcx.sess.time("resolve_check_unused", || self.check_unused(krate)); self.tcx.sess.time("resolve_report_errors", || self.report_errors(krate)); self.tcx .sess .time("resolve_postprocess", || self.crate_loader(|c| c.postprocess(krate))); }); // Make sure we don't mutate the cstore from here on. self.tcx.untracked().cstore.leak(); } fn traits_in_scope( &mut self, current_trait: Option>, parent_scope: &ParentScope<'a>, ctxt: SyntaxContext, assoc_item: Option<(Symbol, Namespace)>, ) -> Vec { let mut found_traits = Vec::new(); if let Some(module) = current_trait { if self.trait_may_have_item(Some(module), assoc_item) { let def_id = module.def_id(); found_traits.push(TraitCandidate { def_id, import_ids: smallvec![] }); } } self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| { match scope { Scope::Module(module, _) => { this.traits_in_module(module, assoc_item, &mut found_traits); } Scope::StdLibPrelude => { if let Some(module) = this.prelude { this.traits_in_module(module, assoc_item, &mut found_traits); } } Scope::ExternPrelude | Scope::ToolPrelude | Scope::BuiltinTypes => {} _ => unreachable!(), } None::<()> }); found_traits } fn traits_in_module( &mut self, module: Module<'a>, assoc_item: Option<(Symbol, Namespace)>, found_traits: &mut Vec, ) { module.ensure_traits(self); let traits = module.traits.borrow(); for (trait_name, trait_binding) in traits.as_ref().unwrap().iter() { if self.trait_may_have_item(trait_binding.module(), assoc_item) { let def_id = trait_binding.res().def_id(); let import_ids = self.find_transitive_imports(&trait_binding.kind, *trait_name); found_traits.push(TraitCandidate { def_id, import_ids }); } } } // List of traits in scope is pruned on best effort basis. We reject traits not having an // associated item with the given name and namespace (if specified). This is a conservative // optimization, proper hygienic type-based resolution of associated items is done in typeck. // We don't reject trait aliases (`trait_module == None`) because we don't have access to their // associated items. fn trait_may_have_item( &mut self, trait_module: Option>, assoc_item: Option<(Symbol, Namespace)>, ) -> bool { match (trait_module, assoc_item) { (Some(trait_module), Some((name, ns))) => { self.resolutions(trait_module).borrow().iter().any(|resolution| { let (&BindingKey { ident: assoc_ident, ns: assoc_ns, .. }, _) = resolution; assoc_ns == ns && assoc_ident.name == name }) } _ => true, } } fn find_transitive_imports( &mut self, mut kind: &NameBindingKind<'_>, trait_name: Ident, ) -> SmallVec<[LocalDefId; 1]> { let mut import_ids = smallvec![]; while let NameBindingKind::Import { import, binding, .. } = kind { if let Some(node_id) = import.id() { let def_id = self.local_def_id(node_id); self.maybe_unused_trait_imports.insert(def_id); import_ids.push(def_id); } self.add_to_glob_map(&import, trait_name); kind = &binding.kind; } import_ids } fn new_key(&mut self, ident: Ident, ns: Namespace) -> BindingKey { let ident = ident.normalize_to_macros_2_0(); let disambiguator = if ident.name == kw::Underscore { self.underscore_disambiguator += 1; self.underscore_disambiguator } else { 0 }; BindingKey { ident, ns, disambiguator } } fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> { if module.populate_on_access.get() { module.populate_on_access.set(false); self.build_reduced_graph_external(module); } &module.lazy_resolutions } fn resolution( &mut self, module: Module<'a>, key: BindingKey, ) -> &'a RefCell> { *self .resolutions(module) .borrow_mut() .entry(key) .or_insert_with(|| self.arenas.alloc_name_resolution()) } /// Test if AmbiguityError ambi is any identical to any one inside ambiguity_errors fn matches_previous_ambiguity_error(&mut self, ambi: &AmbiguityError<'_>) -> bool { for ambiguity_error in &self.ambiguity_errors { // if the span location and ident as well as its span are the same if ambiguity_error.kind == ambi.kind && ambiguity_error.ident == ambi.ident && ambiguity_error.ident.span == ambi.ident.span && ambiguity_error.b1.span == ambi.b1.span && ambiguity_error.b2.span == ambi.b2.span && ambiguity_error.misc1 == ambi.misc1 && ambiguity_error.misc2 == ambi.misc2 { return true; } } false } fn record_use( &mut self, ident: Ident, used_binding: &'a NameBinding<'a>, is_lexical_scope: bool, ) { if let Some((b2, kind)) = used_binding.ambiguity { let ambiguity_error = AmbiguityError { kind, ident, b1: used_binding, b2, misc1: AmbiguityErrorMisc::None, misc2: AmbiguityErrorMisc::None, }; if !self.matches_previous_ambiguity_error(&ambiguity_error) { // avoid dumplicated span information to be emitt out self.ambiguity_errors.push(ambiguity_error); } } if let NameBindingKind::Import { import, binding, ref used } = used_binding.kind { // Avoid marking `extern crate` items that refer to a name from extern prelude, // but not introduce it, as used if they are accessed from lexical scope. if is_lexical_scope { if let Some(entry) = self.extern_prelude.get(&ident.normalize_to_macros_2_0()) { if let Some(crate_item) = entry.extern_crate_item { if ptr::eq(used_binding, crate_item) && !entry.introduced_by_item { return; } } } } used.set(true); import.used.set(true); if let Some(id) = import.id() { self.used_imports.insert(id); } self.add_to_glob_map(&import, ident); self.record_use(ident, binding, false); } } #[inline] fn add_to_glob_map(&mut self, import: &Import<'_>, ident: Ident) { if let ImportKind::Glob { id, .. } = import.kind { let def_id = self.local_def_id(id); self.glob_map.entry(def_id).or_default().insert(ident.name); } } fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> { debug!("resolve_crate_root({:?})", ident); let mut ctxt = ident.span.ctxt(); let mark = if ident.name == kw::DollarCrate { // When resolving `$crate` from a `macro_rules!` invoked in a `macro`, // we don't want to pretend that the `macro_rules!` definition is in the `macro` // as described in `SyntaxContext::apply_mark`, so we ignore prepended opaque marks. // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!` // definitions actually produced by `macro` and `macro` definitions produced by // `macro_rules!`, but at least such configurations are not stable yet. ctxt = ctxt.normalize_to_macro_rules(); debug!( "resolve_crate_root: marks={:?}", ctxt.marks().into_iter().map(|(i, t)| (i.expn_data(), t)).collect::>() ); let mut iter = ctxt.marks().into_iter().rev().peekable(); let mut result = None; // Find the last opaque mark from the end if it exists. while let Some(&(mark, transparency)) = iter.peek() { if transparency == Transparency::Opaque { result = Some(mark); iter.next(); } else { break; } } debug!( "resolve_crate_root: found opaque mark {:?} {:?}", result, result.map(|r| r.expn_data()) ); // Then find the last semi-transparent mark from the end if it exists. for (mark, transparency) in iter { if transparency == Transparency::SemiTransparent { result = Some(mark); } else { break; } } debug!( "resolve_crate_root: found semi-transparent mark {:?} {:?}", result, result.map(|r| r.expn_data()) ); result } else { debug!("resolve_crate_root: not DollarCrate"); ctxt = ctxt.normalize_to_macros_2_0(); ctxt.adjust(ExpnId::root()) }; let module = match mark { Some(def) => self.expn_def_scope(def), None => { debug!( "resolve_crate_root({:?}): found no mark (ident.span = {:?})", ident, ident.span ); return self.graph_root; } }; let module = self.expect_module( module.opt_def_id().map_or(LOCAL_CRATE, |def_id| def_id.krate).as_def_id(), ); debug!( "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})", ident, module, module.kind.name(), ident.span ); module } fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> { let mut module = self.expect_module(module.nearest_parent_mod()); while module.span.ctxt().normalize_to_macros_2_0() != *ctxt { let parent = module.parent.unwrap_or_else(|| self.expn_def_scope(ctxt.remove_mark())); module = self.expect_module(parent.nearest_parent_mod()); } module } fn record_partial_res(&mut self, node_id: NodeId, resolution: PartialRes) { debug!("(recording res) recording {:?} for {}", resolution, node_id); if let Some(prev_res) = self.partial_res_map.insert(node_id, resolution) { panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution); } } fn record_pat_span(&mut self, node: NodeId, span: Span) { debug!("(recording pat) recording {:?} for {:?}", node, span); self.pat_span_map.insert(node, span); } fn is_accessible_from( &self, vis: ty::Visibility>, module: Module<'a>, ) -> bool { vis.is_accessible_from(module.nearest_parent_mod(), self) } fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) { if let Some(old_module) = self.binding_parent_modules.insert(Interned::new_unchecked(binding), module) { if !ptr::eq(module, old_module) { span_bug!(binding.span, "parent module is reset for binding"); } } } fn disambiguate_macro_rules_vs_modularized( &self, macro_rules: &'a NameBinding<'a>, modularized: &'a NameBinding<'a>, ) -> bool { // Some non-controversial subset of ambiguities "modularized macro name" vs "macro_rules" // is disambiguated to mitigate regressions from macro modularization. // Scoping for `macro_rules` behaves like scoping for `let` at module level, in general. match ( self.binding_parent_modules.get(&Interned::new_unchecked(macro_rules)), self.binding_parent_modules.get(&Interned::new_unchecked(modularized)), ) { (Some(macro_rules), Some(modularized)) => { macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod() && modularized.is_ancestor_of(macro_rules) } _ => false, } } fn extern_prelude_get(&mut self, ident: Ident, finalize: bool) -> Option<&'a NameBinding<'a>> { if ident.is_path_segment_keyword() { // Make sure `self`, `super` etc produce an error when passed to here. return None; } self.extern_prelude.get(&ident.normalize_to_macros_2_0()).cloned().and_then(|entry| { if let Some(binding) = entry.extern_crate_item { if finalize && entry.introduced_by_item { self.record_use(ident, binding, false); } Some(binding) } else { let crate_id = if finalize { let Some(crate_id) = self.crate_loader(|c| c.process_path_extern(ident.name, ident.span)) else { return Some(self.dummy_binding); }; crate_id } else { self.crate_loader(|c| c.maybe_process_path_extern(ident.name))? }; let crate_root = self.expect_module(crate_id.as_def_id()); let vis = ty::Visibility::::Public; Some((crate_root, vis, DUMMY_SP, LocalExpnId::ROOT).to_name_binding(self.arenas)) } }) } /// Rustdoc uses this to resolve doc link paths in a recoverable way. `PathResult<'a>` /// isn't something that can be returned because it can't be made to live that long, /// and also it's a private type. Fortunately rustdoc doesn't need to know the error, /// just that an error occurred. fn resolve_rustdoc_path( &mut self, path_str: &str, ns: Namespace, mut parent_scope: ParentScope<'a>, ) -> Option { let mut segments = Vec::from_iter(path_str.split("::").map(Ident::from_str).map(Segment::from_ident)); if let Some(segment) = segments.first_mut() { if segment.ident.name == kw::Crate { // FIXME: `resolve_path` always resolves `crate` to the current crate root, but // rustdoc wants it to resolve to the `parent_scope`'s crate root. This trick of // replacing `crate` with `self` and changing the current module should achieve // the same effect. segment.ident.name = kw::SelfLower; parent_scope.module = self.expect_module(parent_scope.module.def_id().krate.as_def_id()); } else if segment.ident.name == kw::Empty { segment.ident.name = kw::PathRoot; } } match self.maybe_resolve_path(&segments, Some(ns), &parent_scope) { PathResult::Module(ModuleOrUniformRoot::Module(module)) => Some(module.res().unwrap()), PathResult::NonModule(path_res) => path_res.full_res(), PathResult::Module(ModuleOrUniformRoot::ExternPrelude) | PathResult::Failed { .. } => { None } PathResult::Module(..) | PathResult::Indeterminate => unreachable!(), } } /// Retrieves the span of the given `DefId` if `DefId` is in the local crate. #[inline] fn opt_span(&self, def_id: DefId) -> Option { def_id.as_local().map(|def_id| self.tcx.source_span(def_id)) } /// Retrieves the name of the given `DefId`. #[inline] fn opt_name(&self, def_id: DefId) -> Option { let def_key = match def_id.as_local() { Some(def_id) => self.tcx.definitions_untracked().def_key(def_id), None => self.cstore().def_key(def_id), }; def_key.get_opt_name() } /// Checks if an expression refers to a function marked with /// `#[rustc_legacy_const_generics]` and returns the argument index list /// from the attribute. fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option> { if let ExprKind::Path(None, path) = &expr.kind { // Don't perform legacy const generics rewriting if the path already // has generic arguments. if path.segments.last().unwrap().args.is_some() { return None; } let res = self.partial_res_map.get(&expr.id)?.full_res()?; if let Res::Def(def::DefKind::Fn, def_id) = res { // We only support cross-crate argument rewriting. Uses // within the same crate should be updated to use the new // const generics style. if def_id.is_local() { return None; } if let Some(v) = self.legacy_const_generic_args.get(&def_id) { return v.clone(); } let attr = self .cstore() .item_attrs_untracked(def_id, self.tcx.sess) .find(|a| a.has_name(sym::rustc_legacy_const_generics))?; let mut ret = Vec::new(); for meta in attr.meta_item_list()? { match meta.lit()?.kind { LitKind::Int(a, _) => ret.push(a as usize), _ => panic!("invalid arg index"), } } // Cache the lookup to avoid parsing attributes for an item multiple times. self.legacy_const_generic_args.insert(def_id, Some(ret.clone())); return Some(ret); } } None } fn resolve_main(&mut self) { let module = self.graph_root; let ident = Ident::with_dummy_span(sym::main); let parent_scope = &ParentScope::module(module, self); let Ok(name_binding) = self.maybe_resolve_ident_in_module( ModuleOrUniformRoot::Module(module), ident, ValueNS, parent_scope, ) else { return; }; let res = name_binding.res(); let is_import = name_binding.is_import(); let span = name_binding.span; if let Res::Def(DefKind::Fn, _) = res { self.record_use(ident, name_binding, false); } self.main_def = Some(MainDefinition { res, is_import, span }); } // Items that go to reexport table encoded to metadata and visible through it to other crates. fn is_reexport(&self, binding: &NameBinding<'a>) -> Option> { if binding.is_import() { let res = binding.res().expect_non_local(); // Ambiguous imports are treated as errors at this point and are // not exposed to other crates (see #36837 for more details). if res != def::Res::Err && !binding.is_ambiguity() { return Some(res); } } return None; } } fn names_to_string(names: &[Symbol]) -> String { let mut result = String::new(); for (i, name) in names.iter().filter(|name| **name != kw::PathRoot).enumerate() { if i > 0 { result.push_str("::"); } if Ident::with_dummy_span(*name).is_raw_guess() { result.push_str("r#"); } result.push_str(name.as_str()); } result } fn path_names_to_string(path: &Path) -> String { names_to_string(&path.segments.iter().map(|seg| seg.ident.name).collect::>()) } /// A somewhat inefficient routine to obtain the name of a module. fn module_to_string(module: Module<'_>) -> Option { let mut names = Vec::new(); fn collect_mod(names: &mut Vec, module: Module<'_>) { if let ModuleKind::Def(.., name) = module.kind { if let Some(parent) = module.parent { names.push(name); collect_mod(names, parent); } } else { names.push(Symbol::intern("")); collect_mod(names, module.parent.unwrap()); } } collect_mod(&mut names, module); if names.is_empty() { return None; } names.reverse(); Some(names_to_string(&names)) } #[derive(Copy, Clone, Debug)] struct Finalize { /// Node ID for linting. node_id: NodeId, /// Span of the whole path or some its characteristic fragment. /// E.g. span of `b` in `foo::{a, b, c}`, or full span for regular paths. path_span: Span, /// Span of the path start, suitable for prepending something to it. /// E.g. span of `foo` in `foo::{a, b, c}`, or full span for regular paths. root_span: Span, /// Whether to report privacy errors or silently return "no resolution" for them, /// similarly to speculative resolution. report_private: bool, } impl Finalize { fn new(node_id: NodeId, path_span: Span) -> Finalize { Finalize::with_root_span(node_id, path_span, path_span) } fn with_root_span(node_id: NodeId, path_span: Span, root_span: Span) -> Finalize { Finalize { node_id, path_span, root_span, report_private: true } } }