diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arrow-functions/params-default-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arrow-functions/params-default-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,5 @@
+// Parameter default values work in arrow functions
+
+var f = (a=0) => a + 1;
+assertEq(f(), 1);
+assertEq(f(50), 51);