diff --git a/questions/02793-medium-mutable/test-cases.ts b/questions/02793-medium-mutable/test-cases.ts
index bd4b328d..462260b8 100644
--- a/questions/02793-medium-mutable/test-cases.ts
+++ b/questions/02793-medium-mutable/test-cases.ts
@@ -10,6 +10,16 @@ interface Todo1 {
   }
 }
 
+type List = [1, 2, 3]
+
 type cases = [
   Expect<Equal<Mutable<Readonly<Todo1>>, Todo1>>,
+  Expect<Equal<Mutable<Readonly<List>>, List>>,
+]
+
+type errors = [
+  // @ts-expect-error
+  Mutable<'string'>,
+  // @ts-expect-error
+  Mutable<0>,
 ]