Render assoc item owner in hover for items other than functions

crates/hir/src/lib.rs

@@ -2653,6 +2653,37 @@ impl ItemInNs {
     }
 }
 
+/// Invariant: `inner.as_extern_assoc_item(db).is_some()`
+/// We do not actively enforce this invariant.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum ExternAssocItem {
+    Function(Function),
+    Static(Static),
+    TypeAlias(TypeAlias),
+}
+
+pub trait AsExternAssocItem {
+    fn as_extern_assoc_item(self, db: &dyn HirDatabase) -> Option<ExternAssocItem>;
+}
+
+impl AsExternAssocItem for Function {
+    fn as_extern_assoc_item(self, db: &dyn HirDatabase) -> Option<ExternAssocItem> {
+        as_extern_assoc_item(db, ExternAssocItem::Function, self.id)
+    }
+}
+
+impl AsExternAssocItem for Static {
+    fn as_extern_assoc_item(self, db: &dyn HirDatabase) -> Option<ExternAssocItem> {
+        as_extern_assoc_item(db, ExternAssocItem::Static, self.id)
+    }
+}
+
+impl AsExternAssocItem for TypeAlias {
+    fn as_extern_assoc_item(self, db: &dyn HirDatabase) -> Option<ExternAssocItem> {
+        as_extern_assoc_item(db, ExternAssocItem::TypeAlias, self.id)
+    }
+}
+
 /// Invariant: `inner.as_assoc_item(db).is_some()`
 /// We do not actively enforce this invariant.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -2727,6 +2758,63 @@ where
     }
 }
 
+fn as_extern_assoc_item<'db, ID, DEF, LOC>(
+    db: &(dyn HirDatabase + 'db),
+    ctor: impl FnOnce(DEF) -> ExternAssocItem,
+    id: ID,
+) -> Option<ExternAssocItem>
+where
+    ID: Lookup<Database<'db> = dyn DefDatabase + 'db, Data = AssocItemLoc<LOC>>,
+    DEF: From<ID>,
+    LOC: ItemTreeNode,
+{
+    match id.lookup(db.upcast()).container {
+        ItemContainerId::ExternBlockId(_) => Some(ctor(DEF::from(id))),
+        ItemContainerId::TraitId(_) | ItemContainerId::ImplId(_) | ItemContainerId::ModuleId(_) => {
+            None
+        }
+    }
+}
+
+impl ExternAssocItem {
+    pub fn name(self, db: &dyn HirDatabase) -> Name {
+        match self {
+            Self::Function(it) => it.name(db),
+            Self::Static(it) => it.name(db),
+            Self::TypeAlias(it) => it.name(db),
+        }
+    }
+
+    pub fn module(self, db: &dyn HirDatabase) -> Module {
+        match self {
+            Self::Function(f) => f.module(db),
+            Self::Static(c) => c.module(db),
+            Self::TypeAlias(t) => t.module(db),
+        }
+    }
+
+    pub fn as_function(self) -> Option<Function> {
+        match self {
+            Self::Function(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_static(self) -> Option<Static> {
+        match self {
+            Self::Static(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_type_alias(self) -> Option<TypeAlias> {
+        match self {
+            Self::TypeAlias(v) => Some(v),
+            _ => None,
+        }
+    }
+}
+
 impl AssocItem {
     pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
         match self {