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+//! 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_typeck`.
+
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(box_patterns)]
+#![feature(drain_filter)]
+#![feature(if_let_guard)]
+#![feature(iter_intersperse)]
+#![feature(let_chains)]
+#![feature(let_else)]
+#![feature(never_type)]
+#![recursion_limit = "256"]
+#![allow(rustdoc::private_intra_doc_links)]
+#![allow(rustc::potential_query_instability)]
+
+#[macro_use]
+extern crate tracing;
+
+pub use rustc_hir::def::{Namespace, PerNS};
+
+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;
+use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind};
+use rustc_hir::def::Namespace::*;
+use rustc_hir::def::{self, CtorOf, DefKind, LifetimeRes, PartialRes};
+use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId};
+use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::definitions::{DefPathData, Definitions};
+use rustc_hir::TraitCandidate;
+use rustc_index::vec::IndexVec;
+use rustc_metadata::creader::{CStore, CrateLoader};
+use rustc_middle::metadata::ModChild;
+use rustc_middle::middle::privacy::AccessLevels;
+use rustc_middle::span_bug;
+use rustc_middle::ty::query::Providers;
+use rustc_middle::ty::{self, DefIdTree, MainDefinition, RegisteredTools, ResolverOutputs};
+use rustc_query_system::ich::StableHashingContext;
+use rustc_session::cstore::{CrateStore, CrateStoreDyn, MetadataLoaderDyn};
+use rustc_session::lint::LintBuffer;
+use rustc_session::Session;
+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::{cmp, fmt, ptr};
+use tracing::debug;
+
+use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
+use imports::{Import, ImportKind, ImportResolver, NameResolution};
+use late::{HasGenericParams, PathSource, PatternSource};
+use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
+
+use crate::access_levels::AccessLevelsVisitor;
+
+type Res = def::Res<NodeId>;
+
+mod access_levels;
+mod build_reduced_graph;
+mod check_unused;
+mod def_collector;
+mod diagnostics;
+mod ident;
+mod imports;
+mod late;
+mod macros;
+
+enum Weak {
+ Yes,
+ No,
+}
+
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub 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<NodeId>),
+ RegisteredAttrs,
+ 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<NodeId>),
+}
+
+/// 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)]
+pub struct ParentScope<'a> {
+ pub module: Module<'a>,
+ expansion: LocalExpnId,
+ pub 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.
+ pub 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),
+}
+
+#[derive(Eq)]
+struct BindingError {
+ name: Symbol,
+ origin: BTreeSet<Span>,
+ target: BTreeSet<Span>,
+ could_be_path: bool,
+}
+
+impl PartialOrd for BindingError {
+ fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
+ Some(self.cmp(other))
+ }
+}
+
+impl PartialEq for BindingError {
+ fn eq(&self, other: &BindingError) -> bool {
+ self.name == other.name
+ }
+}
+
+impl Ord for BindingError {
+ fn cmp(&self, other: &BindingError) -> cmp::Ordering {
+ self.name.cmp(&other.name)
+ }
+}
+
+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<Symbol>),
+ /// Error E0437: type is not a member of trait.
+ TypeNotMemberOfTrait(Ident, String, Option<Symbol>),
+ /// Error E0438: const is not a member of trait.
+ ConstNotMemberOfTrait(Ident, String, Option<Symbol>),
+ /// 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<LabelSuggestion> },
+ /// 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<Suggestion> },
+ /// 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<LabelSuggestion> },
+ /// 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,
+ },
+ /// 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<Suggestion>),
+ 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)]
+pub struct Segment {
+ ident: Ident,
+ id: Option<NodeId>,
+ /// 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<Segment> {
+ 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::<Vec<_>>())
+ }
+}
+
+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(Clone, Debug)]
+enum PathResult<'a> {
+ Module(ModuleOrUniformRoot<'a>),
+ NonModule(PartialRes),
+ Indeterminate,
+ Failed {
+ span: Span,
+ label: String,
+ suggestion: Option<Suggestion>,
+ 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<Suggestion>),
+ ) -> 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.
+ pub fn name(&self) -> Option<Symbol> {
+ 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<FxIndexMap<BindingKey, &'a RefCell<NameResolution<'a>>>>;
+
+/// 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.
+pub struct ModuleData<'a> {
+ /// The direct parent module (it may not be a `mod`, however).
+ parent: Option<Module<'a>>,
+ /// 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<bool>,
+
+ /// Macro invocations that can expand into items in this module.
+ unexpanded_invocations: RefCell<FxHashSet<LocalExpnId>>,
+
+ /// Whether `#[no_implicit_prelude]` is active.
+ no_implicit_prelude: bool,
+
+ glob_importers: RefCell<Vec<&'a Import<'a>>>,
+ globs: RefCell<Vec<&'a Import<'a>>>,
+
+ /// Used to memoize the traits in this module for faster searches through all traits in scope.
+ traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
+
+ /// 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<Module<'a>>,
+ 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<R, F>(&'a self, resolver: &mut R, mut f: F)
+ where
+ R: AsMut<Resolver<'a>>,
+ 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<R>(&'a self, resolver: &mut R)
+ where
+ R: AsMut<Resolver<'a>>,
+ {
+ 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<Res> {
+ match self.kind {
+ ModuleKind::Def(kind, def_id, _) => Some(Res::Def(kind, def_id)),
+ _ => None,
+ }
+ }
+
+ // Public for rustdoc.
+ pub 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<DefId> {
+ 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)]
+pub struct NameBinding<'a> {
+ kind: NameBindingKind<'a>,
+ ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
+ expansion: LocalExpnId,
+ span: Span,
+ vis: ty::Visibility,
+}
+
+pub 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, /* is_macro_export */ bool),
+ Module(Module<'a>),
+ Import { binding: &'a NameBinding<'a>, import: &'a Import<'a>, used: Cell<bool> },
+}
+
+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<ImportSuggestion>,
+ /// 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<Segment>,
+}
+
+#[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<Module<'a>> {
+ 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 { .. })
+ }
+
+ 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<MacroKind> {
+ 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(Debug, Default, Clone)]
+pub struct ExternPreludeEntry<'a> {
+ extern_crate_item: Option<&'a NameBinding<'a>>,
+ pub 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<SyntaxExtension>,
+ macro_rules: bool,
+}
+
+/// The main resolver class.
+///
+/// This is the visitor that walks the whole crate.
+pub struct Resolver<'a> {
+ session: &'a Session,
+
+ definitions: Definitions,
+ /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
+ expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
+ /// Reference span for definitions.
+ source_span: IndexVec<LocalDefId, Span>,
+
+ graph_root: Module<'a>,
+
+ prelude: Option<Module<'a>>,
+ extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
+
+ /// N.B., this is used only for better diagnostics, not name resolution itself.
+ has_self: FxHashSet<DefId>,
+
+ /// Names of fields of an item `DefId` accessible with dot syntax.
+ /// Used for hints during error reporting.
+ field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
+
+ /// 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<Span>,
+
+ /// Resolutions for nodes that have a single resolution.
+ partial_res_map: NodeMap<PartialRes>,
+ /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
+ import_res_map: NodeMap<PerNS<Option<Res>>>,
+ /// Resolutions for labels (node IDs of their corresponding blocks or loops).
+ label_res_map: NodeMap<NodeId>,
+ /// Resolutions for lifetimes.
+ lifetimes_res_map: NodeMap<LifetimeRes>,
+ /// Mapping from generics `def_id`s to TAIT generics `def_id`s.
+ /// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
+ /// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
+ /// field from the original parameter 'a to the new parameter 'a1.
+ generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
+ /// Lifetime parameters that lowering will have to introduce.
+ extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,
+
+ /// `CrateNum` resolutions of `extern crate` items.
+ extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
+ reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
+ trait_map: NodeMap<Vec<TraitCandidate>>,
+
+ /// 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<Module<'a>>,
+ /// 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<DefId, Module<'a>>,
+ binding_parent_modules: FxHashMap<Interned<'a, NameBinding<'a>>, Module<'a>>,
+ underscore_disambiguator: u32,
+
+ /// Maps glob imports to the names of items actually imported.
+ glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
+ /// Visibilities in "lowered" form, for all entities that have them.
+ visibilities: FxHashMap<LocalDefId, ty::Visibility>,
+ has_pub_restricted: bool,
+ used_imports: FxHashSet<NodeId>,
+ maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
+ maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
+
+ /// Privacy errors are delayed until the end in order to deduplicate them.
+ privacy_errors: Vec<PrivacyError<'a>>,
+ /// Ambiguity errors are delayed for deduplication.
+ ambiguity_errors: Vec<AmbiguityError<'a>>,
+ /// `use` injections are delayed for better placement and deduplication.
+ use_injections: Vec<UseError<'a>>,
+ /// 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>,
+
+ crate_loader: CrateLoader<'a>,
+ macro_names: FxHashSet<Ident>,
+ builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
+ /// 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<LocalDefId, MacroKind>,
+ registered_attrs: FxHashSet<Ident>,
+ registered_tools: RegisteredTools,
+ macro_use_prelude: FxHashMap<Symbol, &'a NameBinding<'a>>,
+ macro_map: FxHashMap<DefId, MacroData>,
+ dummy_ext_bang: Lrc<SyntaxExtension>,
+ dummy_ext_derive: Lrc<SyntaxExtension>,
+ non_macro_attr: Lrc<SyntaxExtension>,
+ local_macro_def_scopes: FxHashMap<LocalDefId, Module<'a>>,
+ ast_transform_scopes: FxHashMap<LocalExpnId, Module<'a>>,
+ unused_macros: FxHashMap<LocalDefId, (NodeId, Ident)>,
+ unused_macro_rules: FxHashMap<(LocalDefId, usize), (Ident, Span)>,
+ proc_macro_stubs: FxHashSet<LocalDefId>,
+ /// 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<Segment>, Span, MacroKind, ParentScope<'a>, Option<Res>)>,
+ 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<LocalExpnId>,
+ /// 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<LocalExpnId, ParentScope<'a>>,
+ /// `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<LocalExpnId, MacroRulesScopeRef<'a>>,
+ /// `macro_rules` scopes produced by `macro_rules` item definitions.
+ macro_rules_scopes: FxHashMap<LocalDefId, MacroRulesScopeRef<'a>>,
+ /// Helper attributes that are in scope for the given expansion.
+ helper_attrs: FxHashMap<LocalExpnId, Vec<Ident>>,
+ /// Ready or in-progress results of resolving paths inside the `#[derive(...)]` attribute
+ /// with the given `ExpnId`.
+ derive_data: FxHashMap<LocalExpnId, DeriveData>,
+
+ /// Avoid duplicated errors for "name already defined".
+ name_already_seen: FxHashMap<Symbol, Span>,
+
+ 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<ty::Visibility>)>,
+
+ /// Features enabled for this crate.
+ active_features: FxHashSet<Symbol>,
+
+ lint_buffer: LintBuffer,
+
+ next_node_id: NodeId,
+
+ node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
+ def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
+
+ /// Indices of unnamed struct or variant fields with unresolved attributes.
+ placeholder_field_indices: FxHashMap<NodeId, usize>,
+ /// 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<LocalExpnId, (LocalDefId, ImplTraitContext)>,
+
+ /// 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<LocalDefId>,
+
+ legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
+ /// Amount of lifetime parameters for each item in the crate.
+ item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
+
+ main_def: Option<MainDefinition>,
+ trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
+ /// 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<NodeId>,
+ confused_type_with_std_module: FxHashMap<Span, Span>,
+
+ access_levels: AccessLevels,
+}
+
+/// Nothing really interesting here; it just provides memory for the rest of the crate.
+#[derive(Default)]
+pub struct ResolverArenas<'a> {
+ modules: TypedArena<ModuleData<'a>>,
+ local_modules: RefCell<Vec<Module<'a>>>,
+ imports: TypedArena<Import<'a>>,
+ name_resolutions: TypedArena<RefCell<NameResolution<'a>>>,
+ ast_paths: TypedArena<ast::Path>,
+ dropless: DroplessArena,
+}
+
+impl<'a> ResolverArenas<'a> {
+ fn new_module(
+ &'a self,
+ parent: Option<Module<'a>>,
+ kind: ModuleKind,
+ expn_id: ExpnId,
+ span: Span,
+ no_implicit_prelude: bool,
+ module_map: &mut FxHashMap<DefId, Module<'a>>,
+ ) -> 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<Module<'a>>> {
+ 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<NameResolution<'a>> {
+ 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<Item = Span>) -> &'a [Span] {
+ self.dropless.alloc_from_iter(spans)
+ }
+}
+
+impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
+ fn as_mut(&mut self) -> &mut Resolver<'a> {
+ self
+ }
+}
+
+impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
+ #[inline]
+ fn opt_parent(self, id: DefId) -> Option<DefId> {
+ match id.as_local() {
+ Some(id) => self.definitions.def_key(id).parent,
+ None => self.cstore().def_key(id).parent,
+ }
+ .map(|index| DefId { index, ..id })
+ }
+}
+
+impl Resolver<'_> {
+ fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
+ self.node_id_to_def_id.get(&node).copied()
+ }
+
+ pub 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.definitions.def_key(self.node_id_to_def_id[&node_id]),
+ );
+
+ let def_id = self.definitions.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.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.session)
+ }
+ }
+}
+
+impl<'a> Resolver<'a> {
+ pub fn new(
+ session: &'a Session,
+ krate: &Crate,
+ crate_name: &str,
+ metadata_loader: Box<MetadataLoaderDyn>,
+ arenas: &'a ResolverArenas<'a>,
+ ) -> Resolver<'a> {
+ 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,
+ session.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 definitions = Definitions::new(session.local_stable_crate_id());
+
+ 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 source_span = IndexVec::default();
+ let _id = source_span.push(krate.spans.inner_span);
+ debug_assert_eq!(_id, CRATE_DEF_ID);
+
+ let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
+ .opts
+ .externs
+ .iter()
+ .filter(|(_, entry)| entry.add_prelude)
+ .map(|(name, _)| (Ident::from_str(name), Default::default()))
+ .collect();
+
+ if !session.contains_name(&krate.attrs, sym::no_core) {
+ extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
+ if !session.contains_name(&krate.attrs, sym::no_std) {
+ extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
+ }
+ }
+
+ let (registered_attrs, registered_tools) =
+ macros::registered_attrs_and_tools(session, &krate.attrs);
+
+ let features = session.features_untracked();
+
+ let mut resolver = Resolver {
+ session,
+
+ definitions,
+ expn_that_defined: Default::default(),
+ source_span,
+
+ // 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(),
+
+ 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(),
+ generics_def_id_map: Vec::new(),
+ 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(),
+ maybe_unused_extern_crates: Vec::new(),
+
+ 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, false),
+ ambiguity: None,
+ expansion: LocalExpnId::ROOT,
+ span: DUMMY_SP,
+ vis: ty::Visibility::Public,
+ }),
+
+ crate_loader: CrateLoader::new(session, metadata_loader, crate_name),
+ macro_names: FxHashSet::default(),
+ builtin_macros: Default::default(),
+ builtin_macro_kinds: Default::default(),
+ registered_attrs,
+ registered_tools,
+ macro_use_prelude: FxHashMap::default(),
+ macro_map: FxHashMap::default(),
+ dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
+ dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
+ non_macro_attr: Lrc::new(SyntaxExtension::non_macro_attr(session.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(),
+ access_levels: 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<Module<'a>>,
+ 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)
+ }
+
+ pub 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
+ }
+
+ pub fn next_node_ids(&mut self, count: usize) -> std::ops::Range<NodeId> {
+ 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,
+ ) -> (Definitions, Box<CrateStoreDyn>, ResolverOutputs, ty::ResolverAstLowering) {
+ let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
+ let definitions = self.definitions;
+ let cstore = Box::new(self.crate_loader.into_cstore());
+ let source_span = self.source_span;
+ 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 maybe_unused_extern_crates = self.maybe_unused_extern_crates;
+ 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 access_levels = self.access_levels;
+ let resolutions = ResolverOutputs {
+ source_span,
+ expn_that_defined,
+ visibilities,
+ has_pub_restricted,
+ access_levels,
+ extern_crate_map,
+ reexport_map,
+ glob_map,
+ maybe_unused_trait_imports,
+ maybe_unused_extern_crates,
+ extern_prelude: self
+ .extern_prelude
+ .iter()
+ .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
+ .collect(),
+ main_def,
+ trait_impls: self.trait_impls,
+ proc_macros,
+ confused_type_with_std_module,
+ registered_tools: self.registered_tools,
+ };
+ let resolutions_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,
+ generics_def_id_map: self.generics_def_id_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,
+ };
+ (definitions, cstore, resolutions, resolutions_lowering)
+ }
+
+ pub fn clone_outputs(
+ &self,
+ ) -> (Definitions, Box<CrateStoreDyn>, ResolverOutputs, ty::ResolverAstLowering) {
+ let proc_macros = self.proc_macros.iter().map(|id| self.local_def_id(*id)).collect();
+ let definitions = self.definitions.clone();
+ let cstore = Box::new(self.cstore().clone());
+ let resolutions = ResolverOutputs {
+ source_span: self.source_span.clone(),
+ expn_that_defined: self.expn_that_defined.clone(),
+ visibilities: self.visibilities.clone(),
+ has_pub_restricted: self.has_pub_restricted,
+ extern_crate_map: self.extern_crate_map.clone(),
+ reexport_map: self.reexport_map.clone(),
+ glob_map: self.glob_map.clone(),
+ maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
+ maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),
+ extern_prelude: self
+ .extern_prelude
+ .iter()
+ .map(|(ident, entry)| (ident.name, entry.introduced_by_item))
+ .collect(),
+ main_def: self.main_def,
+ trait_impls: self.trait_impls.clone(),
+ proc_macros,
+ confused_type_with_std_module: self.confused_type_with_std_module.clone(),
+ registered_tools: self.registered_tools.clone(),
+ access_levels: self.access_levels.clone(),
+ };
+ let resolutions_lowering = ty::ResolverAstLowering {
+ legacy_const_generic_args: self.legacy_const_generic_args.clone(),
+ partial_res_map: self.partial_res_map.clone(),
+ import_res_map: self.import_res_map.clone(),
+ label_res_map: self.label_res_map.clone(),
+ lifetimes_res_map: self.lifetimes_res_map.clone(),
+ generics_def_id_map: self.generics_def_id_map.clone(),
+ extra_lifetime_params_map: self.extra_lifetime_params_map.clone(),
+ next_node_id: self.next_node_id.clone(),
+ node_id_to_def_id: self.node_id_to_def_id.clone(),
+ def_id_to_node_id: self.def_id_to_node_id.clone(),
+ trait_map: self.trait_map.clone(),
+ builtin_macro_kinds: self.builtin_macro_kinds.clone(),
+ };
+ (definitions, cstore, resolutions, resolutions_lowering)
+ }
+
+ fn create_stable_hashing_context(&self) -> StableHashingContext<'_> {
+ StableHashingContext::new(
+ self.session,
+ &self.definitions,
+ self.crate_loader.cstore(),
+ &self.source_span,
+ )
+ }
+
+ pub fn cstore(&self) -> &CStore {
+ self.crate_loader.cstore()
+ }
+
+ fn dummy_ext(&self, macro_kind: MacroKind) -> Lrc<SyntaxExtension> {
+ 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<F: FnMut(&mut Self, Namespace)>(&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.session.time("resolve_crate", || {
+ self.session.time("finalize_imports", || ImportResolver { r: self }.finalize_imports());
+ self.session.time("resolve_access_levels", || {
+ AccessLevelsVisitor::compute_access_levels(self, krate)
+ });
+ self.session.time("finalize_macro_resolutions", || self.finalize_macro_resolutions());
+ self.session.time("late_resolve_crate", || self.late_resolve_crate(krate));
+ self.session.time("resolve_main", || self.resolve_main());
+ self.session.time("resolve_check_unused", || self.check_unused(krate));
+ self.session.time("resolve_report_errors", || self.report_errors(krate));
+ self.session.time("resolve_postprocess", || self.crate_loader.postprocess(krate));
+ });
+ }
+
+ pub fn traits_in_scope(
+ &mut self,
+ current_trait: Option<Module<'a>>,
+ parent_scope: &ParentScope<'a>,
+ ctxt: SyntaxContext,
+ assoc_item: Option<(Symbol, Namespace)>,
+ ) -> Vec<TraitCandidate> {
+ 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<TraitCandidate>,
+ ) {
+ 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<Module<'a>>,
+ 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 {
+ let id = self.local_def_id(import.id);
+ self.maybe_unused_trait_imports.insert(id);
+ self.add_to_glob_map(&import, trait_name);
+ import_ids.push(id);
+ 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<NameResolution<'a>> {
+ *self
+ .resolutions(module)
+ .borrow_mut()
+ .entry(key)
+ .or_insert_with(|| self.arenas.alloc_name_resolution())
+ }
+
+ fn record_use(
+ &mut self,
+ ident: Ident,
+ used_binding: &'a NameBinding<'a>,
+ is_lexical_scope: bool,
+ ) {
+ if let Some((b2, kind)) = used_binding.ambiguity {
+ self.ambiguity_errors.push(AmbiguityError {
+ kind,
+ ident,
+ b1: used_binding,
+ b2,
+ misc1: AmbiguityErrorMisc::None,
+ misc2: AmbiguityErrorMisc::None,
+ });
+ }
+ 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);
+ self.used_imports.insert(import.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 import.is_glob() {
+ let def_id = self.local_def_id(import.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::<Vec<_>>()
+ );
+ 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.process_path_extern(ident.name, ident.span) else { return Some(self.dummy_binding); };
+ crate_id
+ } else {
+ self.crate_loader.maybe_process_path_extern(ident.name)?
+ };
+ let crate_root = self.expect_module(crate_id.as_def_id());
+ Some(
+ (crate_root, ty::Visibility::Public, 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.
+ pub fn resolve_rustdoc_path(
+ &mut self,
+ path_str: &str,
+ ns: Namespace,
+ mut parent_scope: ParentScope<'a>,
+ ) -> Option<Res> {
+ 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) if path_res.unresolved_segments() == 0 => {
+ Some(path_res.base_res())
+ }
+ PathResult::Module(ModuleOrUniformRoot::ExternPrelude)
+ | PathResult::NonModule(..)
+ | PathResult::Failed { .. } => None,
+ PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
+ }
+ }
+
+ /// For rustdoc.
+ /// For local modules returns only reexports, for external modules returns all children.
+ pub fn module_children_or_reexports(&self, def_id: DefId) -> Vec<ModChild> {
+ if let Some(def_id) = def_id.as_local() {
+ self.reexport_map.get(&def_id).cloned().unwrap_or_default()
+ } else {
+ self.cstore().module_children_untracked(def_id, self.session)
+ }
+ }
+
+ /// For rustdoc.
+ pub fn macro_rules_scope(&self, def_id: LocalDefId) -> (MacroRulesScopeRef<'a>, Res) {
+ let scope = *self.macro_rules_scopes.get(&def_id).expect("not a `macro_rules` item");
+ match scope.get() {
+ MacroRulesScope::Binding(mb) => (scope, mb.binding.res()),
+ _ => unreachable!(),
+ }
+ }
+
+ /// Retrieves the span of the given `DefId` if `DefId` is in the local crate.
+ #[inline]
+ pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
+ def_id.as_local().map(|def_id| self.source_span[def_id])
+ }
+
+ /// Checks if an expression refers to a function marked with
+ /// `#[rustc_legacy_const_generics]` and returns the argument index list
+ /// from the attribute.
+ pub fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
+ 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 partial_res = self.partial_res_map.get(&expr.id)?;
+ if partial_res.unresolved_segments() != 0 {
+ return None;
+ }
+
+ if let Res::Def(def::DefKind::Fn, def_id) = partial_res.base_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.session)
+ .find(|a| a.has_name(sym::rustc_legacy_const_generics))?;
+ let mut ret = Vec::new();
+ for meta in attr.meta_item_list()? {
+ match meta.literal()?.kind {
+ LitKind::Int(a, _) => ret.push(a as usize),
+ _ => panic!("invalid arg index"),
+ }
+ }
+ // Cache the lookup to avoid parsing attributes for an iterm 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 });
+ }
+}
+
+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::<Vec<_>>())
+}
+
+/// A somewhat inefficient routine to obtain the name of a module.
+fn module_to_string(module: Module<'_>) -> Option<String> {
+ let mut names = Vec::new();
+
+ fn collect_mod(names: &mut Vec<Symbol>, 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("<opaque>"));
+ 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 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 }
+ }
+}
+
+pub fn provide(providers: &mut Providers) {
+ late::lifetimes::provide(providers);
+}