internal: 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,
-    DefWithBody, DeriveHelper, DocLinkDef, ExternCrateDecl, Field, Function, GenericParam,
-    HasVisibility, HirDisplay, Impl, Label, Local, Macro, Module, ModuleDef, Name, PathResolution,
-    Semantics, Static, ToolModule, Trait, TraitAlias, TupleField, TypeAlias, Variant, VariantDef,
-    Visibility,
+    Adt, AsAssocItem, AsExternAssocItem, AssocItem, AttributeTemplate, BuiltinAttr, BuiltinType,
+    Const, Crate, DefWithBody, DeriveHelper, DocLinkDef, ExternAssocItem, ExternCrateDecl, Field,
+    Function, GenericParam, HasVisibility, HirDisplay, Impl, Label, Local, Macro, Module,
+    ModuleDef, Name, PathResolution, Semantics, Static, ToolModule, Trait, TraitAlias, TupleField,
+    TypeAlias, Variant, VariantDef, Visibility,
 };
 use stdx::{format_to, impl_from};
 use syntax::{
@@ -213,8 +213,8 @@ impl Definition {
         })
     }
 
-    pub fn label(&self, db: &RootDatabase) -> Option<String> {
-        let label = match *self {
+    pub fn label(&self, db: &RootDatabase) -> String {
+        match *self {
             Definition::Macro(it) => it.display(db).to_string(),
             Definition::Field(it) => it.display(db).to_string(),
             Definition::TupleField(it) => it.display(db).to_string(),
@@ -241,16 +241,19 @@ impl Definition {
                 }
             }
             Definition::SelfType(impl_def) => {
-                impl_def.self_ty(db).as_adt().and_then(|adt| Definition::Adt(adt).label(db))?
+                let self_ty = &impl_def.self_ty(db);
+                match self_ty.as_adt() {
+                    Some(it) => it.display(db).to_string(),
+                    None => self_ty.display(db).to_string(),
+                }
             }
             Definition::GenericParam(it) => it.display(db).to_string(),
             Definition::Label(it) => it.name(db).display(db).to_string(),
             Definition::ExternCrateDecl(it) => it.display(db).to_string(),
             Definition::BuiltinAttr(it) => format!("#[{}]", it.name(db)),
             Definition::ToolModule(it) => it.name(db).to_string(),
             Definition::DeriveHelper(it) => format!("derive_helper {}", it.name(db).display(db)),
-        };
-        Some(label)
+        }
     }
 }
 
@@ -739,6 +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.rs

@@ -147,7 +147,7 @@ fn hover_simple(
     if let Some(doc_comment) = token_as_doc_comment(&original_token) {
         cov_mark::hit!(no_highlight_on_comment_hover);
         return doc_comment.get_definition_with_descend_at(sema, offset, |def, node, range| {
-            let res = hover_for_definition(sema, file_id, def, &node, config)?;
+            let res = hover_for_definition(sema, file_id, def, &node, config);
             Some(RangeInfo::new(range, res))
         });
     }
@@ -161,7 +161,7 @@ fn hover_simple(
             Definition::from(resolution?),
             &original_token.parent()?,
             config,
-        )?;
+        );
         return Some(RangeInfo::new(range, res));
     }
 
@@ -215,7 +215,7 @@ fn hover_simple(
                 })
                 .flatten()
                 .unique_by(|&(def, _)| def)
-                .filter_map(|(def, node)| hover_for_definition(sema, file_id, def, &node, config))
+                .map(|(def, node)| hover_for_definition(sema, file_id, def, &node, config))
                 .reduce(|mut acc: HoverResult, HoverResult { markup, actions }| {
                     acc.actions.extend(actions);
                     acc.markup = Markup::from(format!("{}\n---\n{markup}", acc.markup));
@@ -373,9 +373,9 @@ pub(crate) fn hover_for_definition(
     def: Definition,
     scope_node: &SyntaxNode,
     config: &HoverConfig,
-) -> Option<HoverResult> {
+) -> HoverResult {
     let famous_defs = match &def {
-        Definition::BuiltinType(_) => Some(FamousDefs(sema, sema.scope(scope_node)?.krate())),
+        Definition::BuiltinType(_) => sema.scope(scope_node).map(|it| FamousDefs(sema, it.krate())),
         _ => None,
     };
 
@@ -396,20 +396,19 @@ pub(crate) fn hover_for_definition(
     };
     let notable_traits = def_ty.map(|ty| notable_traits(db, &ty)).unwrap_or_default();
 
-    render::definition(sema.db, def, famous_defs.as_ref(), &notable_traits, config).map(|markup| {
-        HoverResult {
-            markup: render::process_markup(sema.db, def, &markup, config),
-            actions: [
-                show_implementations_action(sema.db, def),
-                show_fn_references_action(sema.db, def),
-                runnable_action(sema, def, file_id),
-                goto_type_action_for_def(sema.db, def, &notable_traits),
-            ]
-            .into_iter()
-            .flatten()
-            .collect(),
-        }
-    })
+    let markup = render::definition(sema.db, def, famous_defs.as_ref(), &notable_traits, config);
+    HoverResult {
+        markup: render::process_markup(sema.db, def, &markup, config),
+        actions: [
+            show_implementations_action(sema.db, def),
+            show_fn_references_action(sema.db, def),
+            runnable_action(sema, def, file_id),
+            goto_type_action_for_def(sema.db, def, &notable_traits),
+        ]
+        .into_iter()
+        .flatten()
+        .collect(),
+    }
 }
 
 fn notable_traits(

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,
-    Semantics, Trait, Type, TypeInfo,
+    Adt, AsAssocItem, AsExternAssocItem, CaptureKind, HasCrate, HasSource, HirDisplay, Layout,
+    LayoutError, Name, Semantics, Trait, Type, TypeInfo,
 };
 use ide_db::{
     base_db::SourceDatabase,
@@ -264,7 +264,7 @@ pub(super) fn keyword(
     let markup = process_markup(
         sema.db,
         Definition::Module(doc_owner),
-        &markup(Some(docs.into()), description, None)?,
+        &markup(Some(docs.into()), description, None),
         config,
     );
     Some(HoverResult { markup, actions })
@@ -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())
 }
@@ -396,11 +404,11 @@ pub(super) fn definition(
     famous_defs: Option<&FamousDefs<'_, '_>>,
     notable_traits: &[(Trait, Vec<(Option<Type>, Name)>)],
     config: &HoverConfig,
-) -> Option<Markup> {
+) -> Markup {
     let mod_path = definition_mod_path(db, &def);
-    let label = def.label(db)?;
+    let label = def.label(db);
     let docs = def.docs(db, famous_defs);
-    let value = match def {
+    let value = (|| match def {
         Definition::Variant(it) => {
             if !it.parent_enum(db).is_data_carrying(db) {
                 match it.eval(db) {
@@ -436,7 +444,7 @@ pub(super) fn definition(
             Some(body.to_string())
         }
         _ => None,
-    };
+    })();
 
     let layout_info = match def {
         Definition::Field(it) => render_memory_layout(
@@ -683,7 +691,7 @@ fn definition_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
     def.module(db).map(|module| path(db, module, definition_owner_name(db, def)))
 }
 
-fn markup(docs: Option<String>, desc: String, mod_path: Option<String>) -> Option<Markup> {
+fn markup(docs: Option<String>, desc: String, mod_path: Option<String>) -> Markup {
     let mut buf = String::new();
 
     if let Some(mod_path) = mod_path {
@@ -696,7 +704,7 @@ fn markup(docs: Option<String>, desc: String, mod_path: Option<String>) -> Optio
     if let Some(doc) = docs {
         format_to!(buf, "\n___\n\n{}", doc);
     }
-    Some(buf.into())
+    buf.into()
 }
 
 fn find_std_module(famous_defs: &FamousDefs<'_, '_>, name: &str) -> Option<hir::Module> {