js.compile.ignore=true
=====
>>> main.whiley
type Rec is {int f, int g}

public export method test():
   Rec xs = Rec{f:123, g:456}
   assert xs == {f:223, g: 456}
---
E705 main.whiley 5,10:30
E722 main.whiley 5,10:30
=====
>>> main.whiley 5:6
   assert xs{f:=223} == {f:223, g:456}
---