add day 9

Author: zyhou

2024/09/index.d.ts

@@ -0,0 +1,31 @@
+import type { Expect, Equal } from "type-testing";
+import type { Status, Child, List } from "santas-special-list";
+
+declare module "santas-special-list" {
+  type Status = "naughty" | "nice";
+
+  interface Child {
+    name: string;
+    status: Status;
+  }
+
+  type List = Child[];
+}
+
+// ------------------- Test section ---------------------
+
+type t0_actual = Status; // =>
+type t0_expected = "naughty" | "nice"; // =>
+type t0 = Expect<Equal<t0_actual, t0_expected>>;
+
+type t1_actual = Child; // =>
+interface t1_expected {
+  // =>
+  name: string;
+  status: Status;
+}
+type t1 = Expect<Equal<t1_actual, t1_expected>>;
+
+type t2_actual = List; // =>
+type t2_expected = Child[]; // =>
+type t2 = Expect<Equal<t2_actual, t2_expected>>;