Type error in Promise catch methods as unknown

src/entrypoints/promise-catch.d.ts

@@ -0,0 +1,17 @@
+interface Promise<T> {
+    /**
+     * Attaches callbacks for the resolution and/or rejection of the Promise.
+     * @param onfulfilled The callback to execute when the Promise is resolved.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of which ever callback is executed.
+     */
+    then<TResult1 = T, TResult2 = never>(onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | undefined | null, onrejected?: ((reason: unknown) => TResult2 | PromiseLike<TResult2>) | undefined | null): Promise<TResult1 | TResult2>;
+
+    /**
+     * Attaches a callback for only the rejection of the Promise.
+     * @param onrejected The callback to execute when the Promise is rejected.
+     * @returns A Promise for the completion of the callback.
+     */
+    catch<TResult = never>(onrejected?: ((reason: unknown) => TResult | PromiseLike<TResult>) | undefined | null): Promise<T | TResult>;
+
+}

src/tests/promise-catch.ts

@@ -0,0 +1,13 @@
+import { doNotExecute, Equal, Expect } from "./utils";
+
+doNotExecute(async () => {
+  Promise.reject('string instead of Error').catch((err) => {
+    // @ts-expect-error
+    err.cause;
+  });
+
+  Promise.reject('string instead of Error').then(() => {}, (err) => {
+    // @ts-expect-error
+    err.cause;
+  });
+});