rust/compiler/rustc_hir/src/def.rs
2023-09-26 02:53:59 +00:00

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use crate::hir;
use rustc_ast as ast;
use rustc_ast::NodeId;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::ToStableHashKey;
use rustc_macros::HashStable_Generic;
use rustc_span::def_id::{DefId, LocalDefId};
use rustc_span::hygiene::MacroKind;
use rustc_span::Symbol;
use std::array::IntoIter;
use std::fmt::Debug;
/// Encodes if a `DefKind::Ctor` is the constructor of an enum variant or a struct.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum CtorOf {
/// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit struct.
Struct,
/// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit variant.
Variant,
}
/// What kind of constructor something is.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum CtorKind {
/// Constructor function automatically created by a tuple struct/variant.
Fn,
/// Constructor constant automatically created by a unit struct/variant.
Const,
}
/// An attribute that is not a macro; e.g., `#[inline]` or `#[rustfmt::skip]`.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum NonMacroAttrKind {
/// Single-segment attribute defined by the language (`#[inline]`)
Builtin(Symbol),
/// Multi-segment custom attribute living in a "tool module" (`#[rustfmt::skip]`).
Tool,
/// Single-segment custom attribute registered by a derive macro (`#[serde(default)]`).
DeriveHelper,
/// Single-segment custom attribute registered by a derive macro
/// but used before that derive macro was expanded (deprecated).
DeriveHelperCompat,
}
/// What kind of definition something is; e.g., `mod` vs `struct`.
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum DefKind {
// Type namespace
Mod,
/// Refers to the struct itself, [`DefKind::Ctor`] refers to its constructor if it exists.
Struct,
Union,
Enum,
/// Refers to the variant itself, [`DefKind::Ctor`] refers to its constructor if it exists.
Variant,
Trait,
/// Type alias: `type Foo = Bar;`
TyAlias,
/// Type from an `extern` block.
ForeignTy,
/// Trait alias: `trait IntIterator = Iterator<Item = i32>;`
TraitAlias,
/// Associated type: `trait MyTrait { type Assoc; }`
AssocTy,
/// Type parameter: the `T` in `struct Vec<T> { ... }`
TyParam,
// Value namespace
Fn,
Const,
/// Constant generic parameter: `struct Foo<const N: usize> { ... }`
ConstParam,
Static(ast::Mutability),
/// Refers to the struct or enum variant's constructor.
///
/// The reason `Ctor` exists in addition to [`DefKind::Struct`] and
/// [`DefKind::Variant`] is because structs and enum variants exist
/// in the *type* namespace, whereas struct and enum variant *constructors*
/// exist in the *value* namespace.
///
/// You may wonder why enum variants exist in the type namespace as opposed
/// to the value namespace. Check out [RFC 2593] for intuition on why that is.
///
/// [RFC 2593]: https://github.com/rust-lang/rfcs/pull/2593
Ctor(CtorOf, CtorKind),
/// Associated function: `impl MyStruct { fn associated() {} }`
/// or `trait Foo { fn associated() {} }`
AssocFn,
/// Associated constant: `trait MyTrait { const ASSOC: usize; }`
AssocConst,
// Macro namespace
Macro(MacroKind),
// Not namespaced (or they are, but we don't treat them so)
ExternCrate,
Use,
/// An `extern` block.
ForeignMod,
/// Anonymous constant, e.g. the `1 + 2` in `[u8; 1 + 2]`
AnonConst,
/// An inline constant, e.g. `const { 1 + 2 }`
InlineConst,
/// Opaque type, aka `impl Trait`.
OpaqueTy,
Field,
/// Lifetime parameter: the `'a` in `struct Foo<'a> { ... }`
LifetimeParam,
/// A use of `global_asm!`.
GlobalAsm,
Impl {
of_trait: bool,
},
Closure,
Generator,
}
impl DefKind {
/// Get an English description for the item's kind.
///
/// If you have access to `TyCtxt`, use `TyCtxt::def_descr` or
/// `TyCtxt::def_kind_descr` instead, because they give better
/// information for generators and associated functions.
pub fn descr(self, def_id: DefId) -> &'static str {
match self {
DefKind::Fn => "function",
DefKind::Mod if def_id.is_crate_root() && !def_id.is_local() => "crate",
DefKind::Mod => "module",
DefKind::Static(..) => "static",
DefKind::Enum => "enum",
DefKind::Variant => "variant",
DefKind::Ctor(CtorOf::Variant, CtorKind::Fn) => "tuple variant",
DefKind::Ctor(CtorOf::Variant, CtorKind::Const) => "unit variant",
DefKind::Struct => "struct",
DefKind::Ctor(CtorOf::Struct, CtorKind::Fn) => "tuple struct",
DefKind::Ctor(CtorOf::Struct, CtorKind::Const) => "unit struct",
DefKind::OpaqueTy => "opaque type",
DefKind::TyAlias => "type alias",
DefKind::TraitAlias => "trait alias",
DefKind::AssocTy => "associated type",
DefKind::Union => "union",
DefKind::Trait => "trait",
DefKind::ForeignTy => "foreign type",
DefKind::AssocFn => "associated function",
DefKind::Const => "constant",
DefKind::AssocConst => "associated constant",
DefKind::TyParam => "type parameter",
DefKind::ConstParam => "const parameter",
DefKind::Macro(macro_kind) => macro_kind.descr(),
DefKind::LifetimeParam => "lifetime parameter",
DefKind::Use => "import",
DefKind::ForeignMod => "foreign module",
DefKind::AnonConst => "constant expression",
DefKind::InlineConst => "inline constant",
DefKind::Field => "field",
DefKind::Impl { .. } => "implementation",
DefKind::Closure => "closure",
DefKind::Generator => "generator",
DefKind::ExternCrate => "extern crate",
DefKind::GlobalAsm => "global assembly block",
}
}
/// Gets an English article for the definition.
///
/// If you have access to `TyCtxt`, use `TyCtxt::def_descr_article` or
/// `TyCtxt::def_kind_descr_article` instead, because they give better
/// information for generators and associated functions.
pub fn article(&self) -> &'static str {
match *self {
DefKind::AssocTy
| DefKind::AssocConst
| DefKind::AssocFn
| DefKind::Enum
| DefKind::OpaqueTy
| DefKind::Impl { .. }
| DefKind::Use
| DefKind::InlineConst
| DefKind::ExternCrate => "an",
DefKind::Macro(macro_kind) => macro_kind.article(),
_ => "a",
}
}
pub fn ns(&self) -> Option<Namespace> {
match self {
DefKind::Mod
| DefKind::Struct
| DefKind::Union
| DefKind::Enum
| DefKind::Variant
| DefKind::Trait
| DefKind::OpaqueTy
| DefKind::TyAlias
| DefKind::ForeignTy
| DefKind::TraitAlias
| DefKind::AssocTy
| DefKind::TyParam => Some(Namespace::TypeNS),
DefKind::Fn
| DefKind::Const
| DefKind::ConstParam
| DefKind::Static(..)
| DefKind::Ctor(..)
| DefKind::AssocFn
| DefKind::AssocConst => Some(Namespace::ValueNS),
DefKind::Macro(..) => Some(Namespace::MacroNS),
// Not namespaced.
DefKind::AnonConst
| DefKind::InlineConst
| DefKind::Field
| DefKind::LifetimeParam
| DefKind::ExternCrate
| DefKind::Closure
| DefKind::Generator
| DefKind::Use
| DefKind::ForeignMod
| DefKind::GlobalAsm
| DefKind::Impl { .. } => None,
}
}
#[inline]
pub fn is_fn_like(self) -> bool {
matches!(self, DefKind::Fn | DefKind::AssocFn | DefKind::Closure | DefKind::Generator)
}
/// Whether `query get_codegen_attrs` should be used with this definition.
pub fn has_codegen_attrs(self) -> bool {
match self {
DefKind::Fn
| DefKind::AssocFn
| DefKind::Ctor(..)
| DefKind::Closure
| DefKind::Generator
| DefKind::Static(_) => true,
DefKind::Mod
| DefKind::Struct
| DefKind::Union
| DefKind::Enum
| DefKind::Variant
| DefKind::Trait
| DefKind::TyAlias
| DefKind::ForeignTy
| DefKind::TraitAlias
| DefKind::AssocTy
| DefKind::Const
| DefKind::AssocConst
| DefKind::Macro(..)
| DefKind::Use
| DefKind::ForeignMod
| DefKind::OpaqueTy
| DefKind::Impl { .. }
| DefKind::Field
| DefKind::TyParam
| DefKind::ConstParam
| DefKind::LifetimeParam
| DefKind::AnonConst
| DefKind::InlineConst
| DefKind::GlobalAsm
| DefKind::ExternCrate => false,
}
}
}
/// The resolution of a path or export.
///
/// For every path or identifier in Rust, the compiler must determine
/// what the path refers to. This process is called name resolution,
/// and `Res` is the primary result of name resolution.
///
/// For example, everything prefixed with `/* Res */` in this example has
/// an associated `Res`:
///
/// ```
/// fn str_to_string(s: & /* Res */ str) -> /* Res */ String {
/// /* Res */ String::from(/* Res */ s)
/// }
///
/// /* Res */ str_to_string("hello");
/// ```
///
/// The associated `Res`s will be:
///
/// - `str` will resolve to [`Res::PrimTy`];
/// - `String` will resolve to [`Res::Def`], and the `Res` will include the [`DefId`]
/// for `String` as defined in the standard library;
/// - `String::from` will also resolve to [`Res::Def`], with the [`DefId`]
/// pointing to `String::from`;
/// - `s` will resolve to [`Res::Local`];
/// - the call to `str_to_string` will resolve to [`Res::Def`], with the [`DefId`]
/// pointing to the definition of `str_to_string` in the current crate.
//
#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
#[derive(HashStable_Generic)]
pub enum Res<Id = hir::HirId> {
/// Definition having a unique ID (`DefId`), corresponds to something defined in user code.
///
/// **Not bound to a specific namespace.**
Def(DefKind, DefId),
// Type namespace
/// A primitive type such as `i32` or `str`.
///
/// **Belongs to the type namespace.**
PrimTy(hir::PrimTy),
/// The `Self` type, as used within a trait.
///
/// **Belongs to the type namespace.**
///
/// See the examples on [`Res::SelfTyAlias`] for details.
SelfTyParam {
/// The trait this `Self` is a generic parameter for.
trait_: DefId,
},
/// The `Self` type, as used somewhere other than within a trait.
///
/// **Belongs to the type namespace.**
///
/// Examples:
/// ```
/// struct Bar(Box<Self>); // SelfTyAlias
///
/// trait Foo {
/// fn foo() -> Box<Self>; // SelfTyParam
/// }
///
/// impl Bar {
/// fn blah() {
/// let _: Self; // SelfTyAlias
/// }
/// }
///
/// impl Foo for Bar {
/// fn foo() -> Box<Self> { // SelfTyAlias
/// let _: Self; // SelfTyAlias
///
/// todo!()
/// }
/// }
/// ```
/// *See also [`Res::SelfCtor`].*
///
SelfTyAlias {
/// The item introducing the `Self` type alias. Can be used in the `type_of` query
/// to get the underlying type.
alias_to: DefId,
/// Whether the `Self` type is disallowed from mentioning generics (i.e. when used in an
/// anonymous constant).
///
/// HACK(min_const_generics): self types also have an optional requirement to **not**
/// mention any generic parameters to allow the following with `min_const_generics`:
/// ```
/// # struct Foo;
/// impl Foo { fn test() -> [u8; std::mem::size_of::<Self>()] { todo!() } }
///
/// struct Bar([u8; baz::<Self>()]);
/// const fn baz<T>() -> usize { 10 }
/// ```
/// We do however allow `Self` in repeat expression even if it is generic to not break code
/// which already works on stable while causing the `const_evaluatable_unchecked` future
/// compat lint:
/// ```
/// fn foo<T>() {
/// let _bar = [1_u8; std::mem::size_of::<*mut T>()];
/// }
/// ```
// FIXME(generic_const_exprs): Remove this bodge once that feature is stable.
forbid_generic: bool,
/// Is this within an `impl Foo for bar`?
is_trait_impl: bool,
},
// Value namespace
/// The `Self` constructor, along with the [`DefId`]
/// of the impl it is associated with.
///
/// **Belongs to the value namespace.**
///
/// *See also [`Res::SelfTyParam`] and [`Res::SelfTyAlias`].*
SelfCtor(DefId),
/// A local variable or function parameter.
///
/// **Belongs to the value namespace.**
Local(Id),
/// A tool attribute module; e.g., the `rustfmt` in `#[rustfmt::skip]`.
///
/// **Belongs to the type namespace.**
ToolMod,
// Macro namespace
/// An attribute that is *not* implemented via macro.
/// E.g., `#[inline]` and `#[rustfmt::skip]`, which are essentially directives,
/// as opposed to `#[test]`, which is a builtin macro.
///
/// **Belongs to the macro namespace.**
NonMacroAttr(NonMacroAttrKind), // e.g., `#[inline]` or `#[rustfmt::skip]`
// All namespaces
/// Name resolution failed. We use a dummy `Res` variant so later phases
/// of the compiler won't crash and can instead report more errors.
///
/// **Not bound to a specific namespace.**
Err,
}
/// The result of resolving a path before lowering to HIR,
/// with "module" segments resolved and associated item
/// segments deferred to type checking.
/// `base_res` is the resolution of the resolved part of the
/// path, `unresolved_segments` is the number of unresolved
/// segments.
///
/// ```text
/// module::Type::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/// base_res unresolved_segments = 3
///
/// <T as Trait>::AssocX::AssocY::MethodOrAssocType
/// ^~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~
/// base_res unresolved_segments = 2
/// ```
#[derive(Copy, Clone, Debug)]
pub struct PartialRes {
base_res: Res<NodeId>,
unresolved_segments: usize,
}
impl PartialRes {
#[inline]
pub fn new(base_res: Res<NodeId>) -> Self {
PartialRes { base_res, unresolved_segments: 0 }
}
#[inline]
pub fn with_unresolved_segments(base_res: Res<NodeId>, mut unresolved_segments: usize) -> Self {
if base_res == Res::Err {
unresolved_segments = 0
}
PartialRes { base_res, unresolved_segments }
}
#[inline]
pub fn base_res(&self) -> Res<NodeId> {
self.base_res
}
#[inline]
pub fn unresolved_segments(&self) -> usize {
self.unresolved_segments
}
#[inline]
pub fn full_res(&self) -> Option<Res<NodeId>> {
(self.unresolved_segments == 0).then_some(self.base_res)
}
#[inline]
pub fn expect_full_res(&self) -> Res<NodeId> {
self.full_res().expect("unexpected unresolved segments")
}
}
/// Different kinds of symbols can coexist even if they share the same textual name.
/// Therefore, they each have a separate universe (known as a "namespace").
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Encodable, Decodable)]
#[derive(HashStable_Generic)]
pub enum Namespace {
/// The type namespace includes `struct`s, `enum`s, `union`s, `trait`s, and `mod`s
/// (and, by extension, crates).
///
/// Note that the type namespace includes other items; this is not an
/// exhaustive list.
TypeNS,
/// The value namespace includes `fn`s, `const`s, `static`s, and local variables (including function arguments).
ValueNS,
/// The macro namespace includes `macro_rules!` macros, declarative `macro`s,
/// procedural macros, attribute macros, `derive` macros, and non-macro attributes
/// like `#[inline]` and `#[rustfmt::skip]`.
MacroNS,
}
impl Namespace {
/// The English description of the namespace.
pub fn descr(self) -> &'static str {
match self {
Self::TypeNS => "type",
Self::ValueNS => "value",
Self::MacroNS => "macro",
}
}
}
impl<CTX: crate::HashStableContext> ToStableHashKey<CTX> for Namespace {
type KeyType = Namespace;
#[inline]
fn to_stable_hash_key(&self, _: &CTX) -> Namespace {
*self
}
}
/// Just a helper separate structure for each namespace.
#[derive(Copy, Clone, Default, Debug)]
pub struct PerNS<T> {
pub value_ns: T,
pub type_ns: T,
pub macro_ns: T,
}
impl<T> PerNS<T> {
pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> PerNS<U> {
PerNS { value_ns: f(self.value_ns), type_ns: f(self.type_ns), macro_ns: f(self.macro_ns) }
}
pub fn into_iter(self) -> IntoIter<T, 3> {
[self.value_ns, self.type_ns, self.macro_ns].into_iter()
}
pub fn iter(&self) -> IntoIter<&T, 3> {
[&self.value_ns, &self.type_ns, &self.macro_ns].into_iter()
}
}
impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
type Output = T;
fn index(&self, ns: Namespace) -> &T {
match ns {
Namespace::ValueNS => &self.value_ns,
Namespace::TypeNS => &self.type_ns,
Namespace::MacroNS => &self.macro_ns,
}
}
}
impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
fn index_mut(&mut self, ns: Namespace) -> &mut T {
match ns {
Namespace::ValueNS => &mut self.value_ns,
Namespace::TypeNS => &mut self.type_ns,
Namespace::MacroNS => &mut self.macro_ns,
}
}
}
impl<T> PerNS<Option<T>> {
/// Returns `true` if all the items in this collection are `None`.
pub fn is_empty(&self) -> bool {
self.type_ns.is_none() && self.value_ns.is_none() && self.macro_ns.is_none()
}
/// Returns an iterator over the items which are `Some`.
pub fn present_items(self) -> impl Iterator<Item = T> {
[self.type_ns, self.value_ns, self.macro_ns].into_iter().flatten()
}
}
impl CtorKind {
pub fn from_ast(vdata: &ast::VariantData) -> Option<(CtorKind, NodeId)> {
match *vdata {
ast::VariantData::Tuple(_, node_id) => Some((CtorKind::Fn, node_id)),
ast::VariantData::Unit(node_id) => Some((CtorKind::Const, node_id)),
ast::VariantData::Struct(..) => None,
}
}
}
impl NonMacroAttrKind {
pub fn descr(self) -> &'static str {
match self {
NonMacroAttrKind::Builtin(..) => "built-in attribute",
NonMacroAttrKind::Tool => "tool attribute",
NonMacroAttrKind::DeriveHelper | NonMacroAttrKind::DeriveHelperCompat => {
"derive helper attribute"
}
}
}
pub fn article(self) -> &'static str {
"a"
}
/// Users of some attributes cannot mark them as used, so they are considered always used.
pub fn is_used(self) -> bool {
match self {
NonMacroAttrKind::Tool
| NonMacroAttrKind::DeriveHelper
| NonMacroAttrKind::DeriveHelperCompat => true,
NonMacroAttrKind::Builtin(..) => false,
}
}
}
impl<Id> Res<Id> {
/// Return the `DefId` of this `Def` if it has an ID, else panic.
pub fn def_id(&self) -> DefId
where
Id: Debug,
{
self.opt_def_id().unwrap_or_else(|| panic!("attempted .def_id() on invalid res: {self:?}"))
}
/// Return `Some(..)` with the `DefId` of this `Res` if it has a ID, else `None`.
pub fn opt_def_id(&self) -> Option<DefId> {
match *self {
Res::Def(_, id) => Some(id),
Res::Local(..)
| Res::PrimTy(..)
| Res::SelfTyParam { .. }
| Res::SelfTyAlias { .. }
| Res::SelfCtor(..)
| Res::ToolMod
| Res::NonMacroAttr(..)
| Res::Err => None,
}
}
/// Return the `DefId` of this `Res` if it represents a module.
pub fn mod_def_id(&self) -> Option<DefId> {
match *self {
Res::Def(DefKind::Mod, id) => Some(id),
_ => None,
}
}
/// A human readable name for the res kind ("function", "module", etc.).
pub fn descr(&self) -> &'static str {
match *self {
Res::Def(kind, def_id) => kind.descr(def_id),
Res::SelfCtor(..) => "self constructor",
Res::PrimTy(..) => "builtin type",
Res::Local(..) => "local variable",
Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } => "self type",
Res::ToolMod => "tool module",
Res::NonMacroAttr(attr_kind) => attr_kind.descr(),
Res::Err => "unresolved item",
}
}
/// Gets an English article for the `Res`.
pub fn article(&self) -> &'static str {
match *self {
Res::Def(kind, _) => kind.article(),
Res::NonMacroAttr(kind) => kind.article(),
Res::Err => "an",
_ => "a",
}
}
pub fn map_id<R>(self, mut map: impl FnMut(Id) -> R) -> Res<R> {
match self {
Res::Def(kind, id) => Res::Def(kind, id),
Res::SelfCtor(id) => Res::SelfCtor(id),
Res::PrimTy(id) => Res::PrimTy(id),
Res::Local(id) => Res::Local(map(id)),
Res::SelfTyParam { trait_ } => Res::SelfTyParam { trait_ },
Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl } => {
Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl }
}
Res::ToolMod => Res::ToolMod,
Res::NonMacroAttr(attr_kind) => Res::NonMacroAttr(attr_kind),
Res::Err => Res::Err,
}
}
pub fn apply_id<R, E>(self, mut map: impl FnMut(Id) -> Result<R, E>) -> Result<Res<R>, E> {
Ok(match self {
Res::Def(kind, id) => Res::Def(kind, id),
Res::SelfCtor(id) => Res::SelfCtor(id),
Res::PrimTy(id) => Res::PrimTy(id),
Res::Local(id) => Res::Local(map(id)?),
Res::SelfTyParam { trait_ } => Res::SelfTyParam { trait_ },
Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl } => {
Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl }
}
Res::ToolMod => Res::ToolMod,
Res::NonMacroAttr(attr_kind) => Res::NonMacroAttr(attr_kind),
Res::Err => Res::Err,
})
}
#[track_caller]
pub fn expect_non_local<OtherId>(self) -> Res<OtherId> {
self.map_id(
#[track_caller]
|_| panic!("unexpected `Res::Local`"),
)
}
pub fn macro_kind(self) -> Option<MacroKind> {
match self {
Res::Def(DefKind::Macro(kind), _) => Some(kind),
Res::NonMacroAttr(..) => Some(MacroKind::Attr),
_ => None,
}
}
/// Returns `None` if this is `Res::Err`
pub fn ns(&self) -> Option<Namespace> {
match self {
Res::Def(kind, ..) => kind.ns(),
Res::PrimTy(..) | Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } | Res::ToolMod => {
Some(Namespace::TypeNS)
}
Res::SelfCtor(..) | Res::Local(..) => Some(Namespace::ValueNS),
Res::NonMacroAttr(..) => Some(Namespace::MacroNS),
Res::Err => None,
}
}
/// Always returns `true` if `self` is `Res::Err`
pub fn matches_ns(&self, ns: Namespace) -> bool {
self.ns().map_or(true, |actual_ns| actual_ns == ns)
}
/// Returns whether such a resolved path can occur in a tuple struct/variant pattern
pub fn expected_in_tuple_struct_pat(&self) -> bool {
matches!(self, Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..))
}
/// Returns whether such a resolved path can occur in a unit struct/variant pattern
pub fn expected_in_unit_struct_pat(&self) -> bool {
matches!(self, Res::Def(DefKind::Ctor(_, CtorKind::Const), _) | Res::SelfCtor(..))
}
}
/// Resolution for a lifetime appearing in a type.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum LifetimeRes {
/// Successfully linked the lifetime to a generic parameter.
Param {
/// Id of the generic parameter that introduced it.
param: LocalDefId,
/// Id of the introducing place. That can be:
/// - an item's id, for the item's generic parameters;
/// - a TraitRef's ref_id, identifying the `for<...>` binder;
/// - a BareFn type's id.
///
/// This information is used for impl-trait lifetime captures, to know when to or not to
/// capture any given lifetime.
binder: NodeId,
},
/// Created a generic parameter for an anonymous lifetime.
Fresh {
/// Id of the generic parameter that introduced it.
///
/// Creating the associated `LocalDefId` is the responsibility of lowering.
param: NodeId,
/// Id of the introducing place. See `Param`.
binder: NodeId,
},
/// This variant is used for anonymous lifetimes that we did not resolve during
/// late resolution. Those lifetimes will be inferred by typechecking.
Infer,
/// Explicit `'static` lifetime.
Static,
/// Resolution failure.
Error,
/// HACK: This is used to recover the NodeId of an elided lifetime.
ElidedAnchor { start: NodeId, end: NodeId },
}
pub type DocLinkResMap = FxHashMap<(Symbol, Namespace), Option<Res<NodeId>>>;