UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2929.4 Safari/537.36

Steps to reproduce the problem:
var a = 1; 
setInterval(function(){
   console.log(a);
}, 100);

if I change code to
var a = 1; 
var b = 10;
setInterval(function(){
   console.log(a + b);
}, 100);

I have an error that b is not defined

What is the expected behavior?
after recompile setInterval's function need also rebuild its closure scopes

What went wrong?
error

Did this work before? N/A 

Chrome version: 57.0.2929.4  Channel: canary
OS Version: OS X 10.11.6
Flash Version: Shockwave Flash 24.0 r0