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 {

crates/ide-db/src/defs.rs

@@ -8,11 +8,11 @@
 use arrayvec::ArrayVec;
 use either::Either;
 use hir::{
-    Adt, AsAssocItem, AssocItem, AttributeTemplate, BuiltinAttr, BuiltinType, Const, Crate,
+    Adt, AsAssocItem, AsExternAssocItem, AssocItem, AttributeTemplate, BuiltinAttr, BuiltinType,
-    DefWithBody, DeriveHelper, DocLinkDef, ExternCrateDecl, Field, Function, GenericParam,
+    Const, Crate, DefWithBody, DeriveHelper, DocLinkDef, ExternAssocItem, ExternCrateDecl, Field,
-    HasVisibility, HirDisplay, Impl, Label, Local, Macro, Module, ModuleDef, Name, PathResolution,
+    Function, GenericParam, HasVisibility, HirDisplay, Impl, Label, Local, Macro, Module,
-    Semantics, Static, ToolModule, Trait, TraitAlias, TupleField, TypeAlias, Variant, VariantDef,
+    ModuleDef, Name, PathResolution, Semantics, Static, ToolModule, Trait, TraitAlias, TupleField,
-    Visibility,
+    TypeAlias, Variant, VariantDef, Visibility,
 };
 use stdx::{format_to, impl_from};
 use syntax::{
@@ -742,6 +742,17 @@ impl AsAssocItem for Definition {
     }
 }
 
+impl AsExternAssocItem for Definition {
+    fn as_extern_assoc_item(self, db: &dyn hir::db::HirDatabase) -> Option<ExternAssocItem> {
+        match self {
+            Definition::Function(it) => it.as_extern_assoc_item(db),
+            Definition::Static(it) => it.as_extern_assoc_item(db),
+            Definition::TypeAlias(it) => it.as_extern_assoc_item(db),
+            _ => None,
+        }
+    }
+}
+
 impl From<AssocItem> for Definition {
     fn from(assoc_item: AssocItem) -> Self {
         match assoc_item {

crates/ide/src/hover/render.rs

@@ -3,8 +3,8 @@ use std::{mem, ops::Not};
 
 use either::Either;
 use hir::{
-    Adt, AsAssocItem, CaptureKind, HasCrate, HasSource, HirDisplay, Layout, LayoutError, Name,
+    Adt, AsAssocItem, AsExternAssocItem, CaptureKind, HasCrate, HasSource, HirDisplay, Layout,
-    Semantics, Trait, Type, TypeInfo,
+    LayoutError, Name, Semantics, Trait, Type, TypeInfo,
 };
 use ide_db::{
     base_db::SourceDatabase,
@@ -369,12 +369,20 @@ fn definition_owner_name(db: &RootDatabase, def: &Definition) -> Option<String>
     match def {
         Definition::Field(f) => Some(f.parent_def(db).name(db)),
         Definition::Local(l) => l.parent(db).name(db),
-        Definition::Function(f) => match f.as_assoc_item(db)?.container(db) {
-            hir::AssocItemContainer::Trait(t) => Some(t.name(db)),
-            hir::AssocItemContainer::Impl(i) => i.self_ty(db).as_adt().map(|adt| adt.name(db)),
-        },
         Definition::Variant(e) => Some(e.parent_enum(db).name(db)),
-        _ => None,
+
+        d => {
+            if let Some(assoc_item) = d.as_assoc_item(db) {
+                match assoc_item.container(db) {
+                    hir::AssocItemContainer::Trait(t) => Some(t.name(db)),
+                    hir::AssocItemContainer::Impl(i) => {
+                        i.self_ty(db).as_adt().map(|adt| adt.name(db))
+                    }
+                }
+            } else {
+                return d.as_extern_assoc_item(db).map(|_| "<extern>".to_owned());
+            }
+        }
     }
     .map(|name| name.display(db).to_string())
 }

crates/ide/src/hover/tests.rs

@@ -1202,7 +1202,7 @@ fn main() {
             *C*
 
             ```rust
-            test
+            test::X
             ```
 
             ```rust
@@ -2277,7 +2277,7 @@ fn main() { let foo_test = unsafe { fo$0o(1, 2, 3); } }
             *foo*
 
             ```rust
-            test
+            test::<extern>
             ```
 
             ```rust
@@ -4266,7 +4266,7 @@ fn main() {
             *B*
 
             ```rust
-            test
+            test::T
             ```
 
             ```rust
@@ -4295,7 +4295,7 @@ fn main() {
             *B*
 
             ```rust
-            test
+            test::T
             ```
 
             ```rust
@@ -4327,7 +4327,7 @@ fn main() {
             *B*
 
             ```rust
-            test
+            test::T
             ```
 
             ```rust
@@ -4919,7 +4919,7 @@ fn test() {
             *FOO*
 
             ```rust
-            test
+            test::S
             ```
 
             ```rust
@@ -5284,7 +5284,7 @@ impl T1 for Foo {
             *Bar*
 
             ```rust
-            test::t2
+            test::t2::T2
             ```
 
             ```rust
@@ -5306,7 +5306,7 @@ trait A {
             *Assoc*
 
             ```rust
-            test
+            test::A
             ```
 
             ```rust
@@ -5327,7 +5327,7 @@ trait A {
             *Assoc*
 
             ```rust
-            test
+            test::A
             ```
 
             ```rust
@@ -5346,7 +5346,7 @@ trait A where
             *Assoc*
 
             ```rust
-            test
+            test::A
             ```
 
             ```rust
@@ -6632,7 +6632,7 @@ fn test() {
             *A*
 
             ```rust
-            test
+            test::S
             ```
 
             ```rust
@@ -6661,7 +6661,7 @@ fn test() {
             *A*
 
             ```rust
-            test
+            test::S
             ```
 
             ```rust
@@ -6691,7 +6691,7 @@ mod m {
             *A*
 
             ```rust
-            test
+            test::S
             ```
 
             ```rust
@@ -7249,7 +7249,7 @@ extern "C" {
             *STATIC*
 
             ```rust
-            test
+            test::<extern>
             ```
 
             ```rust
@@ -7267,7 +7267,7 @@ extern "C" {
             *fun*
 
             ```rust
-            test
+            test::<extern>
             ```
 
             ```rust
@@ -7285,7 +7285,7 @@ extern "C" {
             *Ty*
 
             ```rust
-            test
+            test::<extern>
             ```
 
             ```rust