Add regression test for #602
Add regression test for #602

Iced-Tea/immutable-js,cazacugmihai/immutable-js,danielstreit/immutable-js,facebook/immutable-js,james4388/immutable-js,cazacugmihai/immutable-js,Iced-Tea/immutable-js,rawls238/immutable-js,tgrospic/immutable-js,james4388/immutable-js,kad3nce/immutable-js,vlinder/immutable-js,PeterDaveHelloKitchen/immutable-js,donabrams/immutable-js,tgrospic/immutable-js,myitcv/immutable-js,donabrams/immutable-js,james4388/immutable-js,facebook/immutable-js,kangkot/immutable-js,Rich-Harris/immutable-js,redbadger/immutable-js,glenjamin/immutable-js,maxehnert/immutable-js,Dashed/immutable-js,vlinder/immutable-js,Jonekee/immutable-js,xiaoking/immutable-js,Rich-Harris/immutable-js,PeterDaveHelloKitchen/immutable-js,glenjamin/immutable-js,leeleo26/immutable-js,mcanthony/immutable-js,renyaoxiang/immutable-js,facebook/immutable-js,donabrams/immutable-js,Iced-Tea/immutable-js,glenjamin/immutable-js,Jonekee/immutable-js,tgrospic/immutable-js,leeleo26/immutable-js,kad3nce/immutable-js,kangkot/immutable-js,xiaoking/immutable-js,redbadger/immutable-js,renyaoxiang/immutable-js,danielstreit/immutable-js,mcanthony/immutable-js,Dashed/immutable-js,redbadger/immutable-js,rawls238/immutable-js,myitcv/immutable-js,vlinder/immutable-js,renyaoxiang/immutable-js,leeleo26/immutable-js,cazacugmihai/immutable-js,Dashed/immutable-js,maxehnert/immutable-js,Rich-Harris/immutable-js,mcanthony/immutable-js,maxehnert/immutable-js,kangkot/immutable-js,PeterDaveHelloKitchen/immutable-js,danielstreit/immutable-js,rawls238/immutable-js,Jonekee/immutable-js,xiaoking/immutable-js,maxehnert/immutable-js,myitcv/immutable-js,facebook/immutable-js,kad3nce/immutable-js