diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arrow-functions/params-default-2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arrow-functions/params-default-2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,6 @@
+// Parameter default values work in arrow functions
+
+var f = (a=1, b=2, ...rest) => [a, b, rest];
+assertEq(f().toSource(), "[1, 2, []]");
+assertEq(f(0, 0).toSource(), "[0, 0, []]");
+assertEq(f(0, 1, 1, 2, 3, 5).toSource(), "[0, 1, [1, 2, 3, 5]]");