Nashorn: setter not called

FULL PRODUCT VERSION :
java version "1.8.0-ea"
Java(TM) SE Runtime Environment (build 1.8.0-ea-b115)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b57, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Darwin Laskey.local 13.0.0 Darwin Kernel Version 13.0.0: Thu Sep 19 22:22:27 PDT 2013; root:xnu-2422.1.72~6/RELEASE_X86_64 x86_64


A DESCRIPTION OF THE PROBLEM :
Setter function in JSON.parse filter not called.

REGRESSION. Last worked in version 8

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. run jjs
2. enter test case
3. check result

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
p:a-0
456
p:x-null
whoa
p:b-[object Object]
p:-[object Object]
[object Object]

ACTUAL -
p:a-0
456
p:x-null
p:b-[object Object]
p:-[object Object]
[object Object]


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
JSON.parse('{"a":0,"b":1}', function(p,v){print("p:"+p+"-"+v); if(p=="a"){ this.b = {get x(){print("456"); return null}, set x(_){print("whoa")}} } return v})
---------- END SOURCE ----------