diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/arityMismatchExtraArg.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/arityMismatchExtraArg.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+function arityMismatchMissingArg(arg)
+{
+  for (var a = 0, i = 1; i < 10000; i *= 2) {
+    a += i;
+  }
+  return a;
+}
+
+function arityMismatchExtraArg()
+{
+  return arityMismatchMissingArg(1, 2);
+}
+assertEq(arityMismatchExtraArg(), 16383);