Replace entire impl def instead of only associated items for missing impl member assist (if braces are missing from an impl def then there is no associated item list in the AST)

Author: M-J-Hooper

crates/assists/src/handlers/add_missing_impl_members.rs

@@ -111,8 +111,6 @@ fn add_missing_impl_members_inner(
 ) -> Option<()> {
     let _p = profile::span("add_missing_impl_members_inner");
     let impl_def = ctx.find_node_at_offset::<ast::Impl>()?;
-    let impl_item_list = impl_def.assoc_item_list()?;
-
     let trait_ = resolve_target_trait(&ctx.sema, &impl_def)?;
 
     let def_name = |item: &ast::AssocItem| -> Option<SmolStr> {
@@ -148,11 +146,14 @@ fn add_missing_impl_members_inner(
 
     let target = impl_def.syntax().text_range();
     acc.add(AssistId(assist_id, AssistKind::QuickFix), label, target, |builder| {
+        let impl_item_list = impl_def.assoc_item_list().unwrap_or(make::assoc_item_list());
+
         let n_existing_items = impl_item_list.assoc_items().count();
         let source_scope = ctx.sema.scope_for_def(trait_);
-        let target_scope = ctx.sema.scope(impl_item_list.syntax());
+        let target_scope = ctx.sema.scope(impl_def.syntax());
         let ast_transform = QualifyPaths::new(&target_scope, &source_scope)
-            .or(SubstituteTypeParams::for_trait_impl(&source_scope, trait_, impl_def));
+            .or(SubstituteTypeParams::for_trait_impl(&source_scope, trait_, impl_def.clone()));
+
         let items = missing_items
             .into_iter()
             .map(|it| ast_transform::apply(&*ast_transform, it))
@@ -162,12 +163,14 @@ fn add_missing_impl_members_inner(
                 _ => it,
             })
             .map(|it| edit::remove_attrs_and_docs(&it));
+
         let new_impl_item_list = impl_item_list.append_items(items);
-        let first_new_item = new_impl_item_list.assoc_items().nth(n_existing_items).unwrap();
+        let new_impl_def = impl_def.with_items(new_impl_item_list);
+        let first_new_item =
+            new_impl_def.assoc_item_list().unwrap().assoc_items().nth(n_existing_items).unwrap();
 
-        let original_range = impl_item_list.syntax().text_range();
         match ctx.config.snippet_cap {
-            None => builder.replace(original_range, new_impl_item_list.to_string()),
+            None => builder.replace(target, new_impl_def.to_string()),
             Some(cap) => {
                 let mut cursor = Cursor::Before(first_new_item.syntax());
                 let placeholder;
@@ -181,8 +184,8 @@ fn add_missing_impl_members_inner(
                 }
                 builder.replace_snippet(
                     cap,
-                    original_range,
-                    render_snippet(cap, new_impl_item_list.syntax(), cursor),
+                    target,
+                    render_snippet(cap, new_impl_def.syntax(), cursor),
                 )
             }
         };