Add tests

Author: ahejlsberg

tests/cases/conformance/types/rest/genericRestArity.ts

@@ -0,0 +1,8 @@
+// Repro from #25559
+
+declare function call<TS extends unknown[]>(
+    handler: (...args: TS) => void,
+    ...args: TS): void;
+  
+call((x: number, y: number) => x + y);
+call((x: number, y: number) => x + y, 1, 2, 3, 4, 5, 6, 7);

tests/cases/conformance/types/rest/genericRestArityStrict.ts

@@ -0,0 +1,10 @@
+// @strict: true
+
+// Repro from #25559
+
+declare function call<TS extends unknown[]>(
+    handler: (...args: TS) => void,
+    ...args: TS): void;
+  
+call((x: number, y: number) => x + y);
+call((x: number, y: number) => x + y, 1, 2, 3, 4, 5, 6, 7);