diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug854124.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug854124.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// Don't assert.
+"p".match(/(p)/);
+assertEq(RegExp.$1, "p");
+assertEq(RegExp.$2, "");
+
+"x\ny\n".replace(/(^\n*)/, "");
+assertEq(RegExp.$1, "");
+assertEq(RegExp.$2, "");