Fix handling of cascadedModifierTags

Resolves #2802

CHANGELOG.md

@@ -4,6 +4,10 @@ title: Changelog
 
 ## Unreleased
 
+### Bug Fixes
+
+-   Cascaded modifier tags will no longer be copied into type literals, #2802.
+
 ## v0.27.3 (2024-12-04)
 
 ### Features

src/lib/converter/plugins/CommentPlugin.ts

@@ -453,7 +453,7 @@ export class CommentPlugin extends ConverterComponent {
 
             // Any cascaded tags will show up twice, once on this and once on our signatures
             // This is completely redundant, so remove them from the wrapping function.
-            if (sigs.length) {
+            if (sigs.length && reflection.type?.type !== "reflection") {
                 for (const mod of this.cascadedModifierTags) {
                     reflection.comment.modifierTags.delete(mod);
                 }
@@ -527,7 +527,9 @@ export class CommentPlugin extends ConverterComponent {
 
     private cascadeModifiers(reflection: Reflection) {
         const parentComment = reflection.parent?.comment;
-        if (!parentComment) return;
+        if (!parentComment || reflection.kindOf(ReflectionKind.TypeLiteral)) {
+            return;
+        }
 
         const childMods = reflection.comment?.modifierTags ?? new Set();
 

src/test/converter2/issues/gh2802.ts

@@ -0,0 +1,11 @@
+/**
+ * Docs
+ * @alpha
+ */
+export type AlphaOk = number | string;
+
+/**
+ * Docs2
+ * @alpha
+ */
+export type AlphaNoGo = (arg: number | string) => void;

src/test/issues.c2.test.ts

@@ -1942,4 +1942,19 @@ describe("Issue Tests", () => {
         const type = query(project, "typeType");
         equal(type.type?.toString(), "any");
     });
+
+    it("#2802 preserves @alpha tags on signature types", () => {
+        const project = convert();
+        const alpha1 = query(project, "AlphaOk");
+        equal(Comment.combineDisplayParts(alpha1.comment?.summary), "Docs");
+        ok(alpha1.comment?.hasModifier("@alpha"));
+
+        const alpha2 = query(project, "AlphaNoGo");
+        equal(Comment.combineDisplayParts(alpha2.comment?.summary), "Docs2");
+        ok(alpha2.comment?.hasModifier("@alpha"));
+
+        // Modifiers should not have been cascaded
+        equal(alpha2.type?.type, "reflection");
+        equal(alpha2.type.declaration.comment, undefined);
+    });
 });