+use std::{

+ hash::{Hash, Hasher},

+ panic::{RefUnwindSafe, UnwindSafe},

+};

+ Const, Enum, Function, Impl, ItemTreeId, ItemTreeNode, MacroDef, MacroRules, Static,

+ Struct, Trait, TraitAlias, TypeAlias, Union,

+/// Id of the anonymous const block expression and patterns. This is very similar to `ClosureId` and

+/// shouldn't be a `DefWithBodyId` since its type inference is dependent on its parent.

+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]

+pub struct ConstBlockId(InternId);

+impl_intern_key!(ConstBlockId);

+

+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]

+pub enum TypeOwnerId {

+ FunctionId(FunctionId),

+ StaticId(StaticId),

+ ConstId(ConstId),

+ InTypeConstId(InTypeConstId),

+ AdtId(AdtId),

+ TraitId(TraitId),

+ TraitAliasId(TraitAliasId),

+ TypeAliasId(TypeAliasId),

+ ImplId(ImplId),

+ EnumVariantId(EnumVariantId),

+ // FIXME(const-generic-body): ModuleId should not be a type owner. This needs to be fixed to make `TypeOwnerId` actually

+ // useful for assigning ids to in type consts.

+ ModuleId(ModuleId),

+}

+

+impl TypeOwnerId {

+ fn as_generic_def_id(self) -> Option<GenericDefId> {

+ Some(match self {

+ TypeOwnerId::FunctionId(x) => GenericDefId::FunctionId(x),

+ TypeOwnerId::ConstId(x) => GenericDefId::ConstId(x),

+ TypeOwnerId::AdtId(x) => GenericDefId::AdtId(x),

+ TypeOwnerId::TraitId(x) => GenericDefId::TraitId(x),

+ TypeOwnerId::TraitAliasId(x) => GenericDefId::TraitAliasId(x),

+ TypeOwnerId::TypeAliasId(x) => GenericDefId::TypeAliasId(x),

+ TypeOwnerId::ImplId(x) => GenericDefId::ImplId(x),

+ TypeOwnerId::EnumVariantId(x) => GenericDefId::EnumVariantId(x),

+ TypeOwnerId::InTypeConstId(_) | TypeOwnerId::ModuleId(_) | TypeOwnerId::StaticId(_) => {

+ return None

+ }

+ })

+ }

+}

+

+impl_from!(

+ FunctionId,

+ StaticId,

+ ConstId,

+ InTypeConstId,

+ AdtId,

+ TraitId,

+ TraitAliasId,

+ TypeAliasId,

+ ImplId,

+ EnumVariantId,

+ ModuleId

+ for TypeOwnerId

+);

+

+// Every `DefWithBodyId` is a type owner, since bodies can contain type (e.g. `{ let x: Type = _; }`)

+impl From<DefWithBodyId> for TypeOwnerId {

+ fn from(value: DefWithBodyId) -> Self {

+ match value {

+ DefWithBodyId::FunctionId(x) => x.into(),

+ DefWithBodyId::StaticId(x) => x.into(),

+ DefWithBodyId::ConstId(x) => x.into(),

+ DefWithBodyId::InTypeConstId(x) => x.into(),

+ DefWithBodyId::VariantId(x) => x.into(),

+ }

+ }

+}

+

+impl From<GenericDefId> for TypeOwnerId {

+ fn from(value: GenericDefId) -> Self {

+ match value {

+ GenericDefId::FunctionId(x) => x.into(),

+ GenericDefId::AdtId(x) => x.into(),

+ GenericDefId::TraitId(x) => x.into(),

+ GenericDefId::TraitAliasId(x) => x.into(),

+ GenericDefId::TypeAliasId(x) => x.into(),

+ GenericDefId::ImplId(x) => x.into(),

+ GenericDefId::EnumVariantId(x) => x.into(),

+ GenericDefId::ConstId(x) => x.into(),

+ }

+ }

+}

+

+/// A thing that we want to store in interned ids, but we don't know its type in `hir-def`. This is

+/// currently only used in `InTypeConstId` for storing the type (which has type `Ty` defined in

+/// the `hir-ty` crate) of the constant in its id, which is a temporary hack so we may want

+/// to remove this after removing that.

+pub trait OpaqueInternableThing:

+ std::any::Any + std::fmt::Debug + Sync + Send + UnwindSafe + RefUnwindSafe

+{

+ fn as_any(&self) -> &dyn std::any::Any;

+ fn box_any(&self) -> Box<dyn std::any::Any>;

+ fn dyn_hash(&self, state: &mut dyn Hasher);

+ fn dyn_eq(&self, other: &dyn OpaqueInternableThing) -> bool;

+ fn dyn_clone(&self) -> Box<dyn OpaqueInternableThing>;

+}

+

+impl Hash for dyn OpaqueInternableThing {

+ fn hash<H: Hasher>(&self, state: &mut H) {

+ self.dyn_hash(state);

+ }

+}

+

+impl PartialEq for dyn OpaqueInternableThing {

+ fn eq(&self, other: &Self) -> bool {

+ self.dyn_eq(other)

+ }

+}

+

+impl Eq for dyn OpaqueInternableThing {}

+

+impl Clone for Box<dyn OpaqueInternableThing> {

+ fn clone(&self) -> Self {

+ self.dyn_clone()

+ }

+}

+

+// FIXME(const-generic-body): Use an stable id for in type consts.

+//

+// The current id uses `AstId<ast::ConstArg>` which will be changed by every change in the code. Ideally

+// we should use an id which is relative to the type owner, so that every change will only invalidate the

+// id if it happens inside of the type owner.

+//

+// The solution probably is to have some query on `TypeOwnerId` to traverse its constant children and store

+// their `AstId` in a list (vector or arena), and use the index of that list in the id here. That query probably

+// needs name resolution, and might go far and handles the whole path lowering or type lowering for a `TypeOwnerId`.

+//

+// Whatever path the solution takes, it should answer 3 questions at the same time:

+// * Is the id stable enough?

+// * How to find a constant id using an ast node / position in the source code? This is needed when we want to

+// provide ide functionalities inside an in type const (which we currently don't support) e.g. go to definition

+// for a local defined there. A complex id might have some trouble in this reverse mapping.

+// * How to find the return type of a constant using its id? We have this data when we are doing type lowering

+// and the name of the struct that contains this constant is resolved, so a query that only traverses the

+// type owner by its syntax tree might have a hard time here.

+

+/// A constant in a type as a substitution for const generics (like `Foo<{ 2 + 2 }>`) or as an array

+/// length (like `[u8; 2 + 2]`). These constants are body owner and are a variant of `DefWithBodyId`. These

+/// are not called `AnonymousConstId` to prevent confusion with [`ConstBlockId`].

+pub struct InTypeConstId(InternId);

+type InTypeConstLoc = (AstId<ast::ConstArg>, TypeOwnerId, Box<dyn OpaqueInternableThing>);

+impl_intern!(InTypeConstId, InTypeConstLoc, intern_in_type_const, lookup_intern_in_type_const);

+

+impl InTypeConstId {

+ pub fn source(&self, db: &dyn db::DefDatabase) -> ast::ConstArg {

+ let src = self.lookup(db).0;

+ let file_id = src.file_id;

+ let root = &db.parse_or_expand(file_id);

+ db.ast_id_map(file_id).get(src.value).to_node(root)

+ }

+}

+ ConstBlockId(ConstBlockId),

+ InTypeConstId(InTypeConstId),

+impl_from!(ConstId, ConstBlockId, InTypeConstId for GeneralConstId);

+ GeneralConstId::ConstBlockId(x) => {

+ GeneralConstId::InTypeConstId(x) => {

+ let (_, parent, _) = x.lookup(db);

+ parent.as_generic_def_id()

+ }

+ GeneralConstId::ConstBlockId(id) => format!("{{anonymous const {id:?}}}"),

+ GeneralConstId::InTypeConstId(id) => format!("{{in type const {id:?}}}"),

+ InTypeConstId(InTypeConstId),

+impl_from!(FunctionId, ConstId, StaticId, InTypeConstId for DefWithBodyId);

+ // FIXME: stable rust doesn't allow generics in constants, but we should

+ // use `TypeOwnerId::as_generic_def_id` when it does.

+ DefWithBodyId::InTypeConstId(_) => None,

+impl HasModule for TypeOwnerId {

+ TypeOwnerId::FunctionId(x) => x.lookup(db).module(db),

+ TypeOwnerId::StaticId(x) => x.lookup(db).module(db),

+ TypeOwnerId::ConstId(x) => x.lookup(db).module(db),

+ TypeOwnerId::InTypeConstId(x) => x.lookup(db).1.module(db),

+ TypeOwnerId::AdtId(x) => x.module(db),

+ TypeOwnerId::TraitId(x) => x.lookup(db).container,

+ TypeOwnerId::TraitAliasId(x) => x.lookup(db).container,

+ TypeOwnerId::TypeAliasId(x) => x.lookup(db).module(db),

+ TypeOwnerId::ImplId(x) => x.lookup(db).container,

+ TypeOwnerId::EnumVariantId(x) => x.parent.lookup(db).container,

+ TypeOwnerId::ModuleId(x) => *x,

+impl HasModule for DefWithBodyId {

+ fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {

+ DefWithBodyId::FunctionId(it) => it.lookup(db).module(db),

+ DefWithBodyId::StaticId(it) => it.lookup(db).module(db),

+ DefWithBodyId::ConstId(it) => it.lookup(db).module(db),

+ DefWithBodyId::VariantId(it) => it.parent.lookup(db).container,

+ DefWithBodyId::InTypeConstId(it) => it.lookup(db).1.module(db),