rust/compiler/rustc_resolve/src/lib.rs
2022-07-25 19:19:23 +02:00

2082 lines
76 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//! 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)]
#![cfg_attr(bootstrap, feature(let_chains))]
#![feature(iter_intersperse)]
#![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(NodeId),
/// 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>,
/// 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(),
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,
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(),
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);
}