Add failing test

concept-code/vs.d.ts

@@ -6,6 +6,14 @@ declare namespace vs {
   export function inc(x: number): void;
 }
 
+declare namespace Debug {
+  export function log(...args: unknown[]): void;
+
+  export function makeCopyCounter<T = undefined>(
+    tag?: T,
+  ): { tag: T; count: number };
+}
+
 declare module "ffi:console" {
   type Console = {
     log(...args: unknown[]): void;

inputs/failing/copyCounting/subscript.ts

@@ -0,0 +1,8 @@
+//! test_output(1)
+// Should be: 0
+
+/// <reference path="../../../concept-code/vs.d.ts" />
+
+export default function main() {
+  return Debug.makeCopyCounter("x").count;
+}