Remove fn has default generic

Author: A4-Tacks

crates/ide-assists/src/handlers/extract_to_default_generic.rs

@@ -25,7 +25,7 @@ pub(crate) fn extract_to_default_generic(acc: &mut Assists, ctx: &AssistContext<
     }
 
     let ty: Either<ast::Type, ast::ConstArg> = ctx.find_node_at_range()?;
-    let adt: Either<ast::Adt, Either<ast::TypeAlias, ast::Fn>> =
+    let adt: Either<Either<ast::Adt, ast::TypeAlias>, ast::Fn> =
         ty.syntax().ancestors().find_map(AstNode::cast)?;
 
     extract_to_default_generic_impl(acc, ctx, adt, ty)
@@ -34,48 +34,60 @@ pub(crate) fn extract_to_default_generic(acc: &mut Assists, ctx: &AssistContext<
 fn extract_to_default_generic_impl(
     acc: &mut Assists,
     ctx: &AssistContext<'_>,
-    adt: impl HasName + HasGenericParams,
+    adt: Either<impl HasName + HasGenericParams, ast::Fn>,
     ty: Either<ast::Type, ast::ConstArg>,
 ) -> Option<()> {
     let name = adt.name()?;
+    let has_default = adt.is_left();
 
+    let label = if has_default {
+        "Extract type as default generic parameter"
+    } else {
+        "Extract type as generic parameter"
+    };
     let target = ty.syntax().text_range();
-    acc.add(
-        AssistId::refactor_extract("extract_to_default_generic"),
-        "Extract type as default generic parameter",
-        target,
-        |edit| {
-            let mut editor = edit.make_editor(adt.syntax());
-            let generic_list = get_or_create_generic_param_list(&name, &adt, &mut editor, edit);
-
-            let generic_name = generic_name(&generic_list, ty.is_right());
-
-            editor.replace(ty.syntax(), generic_name.syntax());
-
-            match ty {
-                Left(ty) => {
-                    let param = make::type_default_param(generic_name, None, ty).clone_for_update();
-                    generic_list.add_generic_param(param.into());
+    acc.add(AssistId::refactor_extract("extract_to_default_generic"), label, target, |edit| {
+        let mut editor = edit.make_editor(adt.syntax());
+        let generic_list = get_or_create_generic_param_list(&name, &adt, &mut editor, edit);
+
+        let generic_name = generic_name(&generic_list, ty.is_right());
+
+        editor.replace(ty.syntax(), generic_name.syntax());
+
+        match ty {
+            Left(ty) => {
+                let param = if has_default {
+                    make::type_default_param(generic_name, None, ty)
+                } else {
+                    make::type_param(generic_name, None)
+                }
+                .clone_for_update();
+
+                generic_list.add_generic_param(param.into());
+            }
+            Right(n) => {
+                let param = if has_default {
+                    make::const_default_param(generic_name, const_ty(ctx, &n), n)
+                } else {
+                    make::const_param(generic_name, const_ty(ctx, &n))
                 }
-                Right(n) => {
-                    let param = make::const_default_param(generic_name, const_ty(ctx, &n), n)
-                        .clone_for_update();
-                    generic_list.add_generic_param(param.into());
-
-                    if let Some(ast::GenericParam::ConstParam(param)) =
-                        generic_list.generic_params().last()
-                        && let Some(ast::Type::InferType(ty)) = param.ty()
-                        && let Some(cap) = ctx.config.snippet_cap
-                    {
-                        let annotation = edit.make_placeholder_snippet(cap);
-                        editor.add_annotation(ty.syntax(), annotation);
-                    }
+                .clone_for_update();
+
+                generic_list.add_generic_param(param.into());
+
+                if let Some(ast::GenericParam::ConstParam(param)) =
+                    generic_list.generic_params().last()
+                    && let Some(ast::Type::InferType(ty)) = param.ty()
+                    && let Some(cap) = ctx.config.snippet_cap
+                {
+                    let annotation = edit.make_placeholder_snippet(cap);
+                    editor.add_annotation(ty.syntax(), annotation);
                 }
             }
+        }
 
-            edit.add_file_edits(ctx.vfs_file_id(), editor);
-        },
-    )
+        edit.add_file_edits(ctx.vfs_file_id(), editor);
+    })
 }
 
 fn array_index_type(n: &ast::ConstArg) -> Option<ast::Type> {
@@ -184,7 +196,7 @@ mod tests {
         check_assist(
             extract_to_default_generic,
             r#"fn foo(x: $0i32$0) {}"#,
-            r#"fn foo<T = i32>(x: T) {}"#,
+            r#"fn foo<T>(x: T) {}"#,
         );
     }