While I haven't encounter this in my programming, it popped out in
another thread and I think something might be done about it:

#type t1 = {fst:int;snd:int};; 
#let p1 = {fst=1; snd=2};; 
#type t2 = {snd:int};; 
#{p1 with snd=4};; 
- : t2 = {snd = 4};; 

Best Regards,
Lukasz