else raise UnificationFailed
| (C.MutCase (_,_,_,outt1,t1,pl1), C.MutCase (_,_,_,outt2,t2,pl2))->
let subst' = fo_unif_aux subst k outt1 outt2 in
else raise UnificationFailed
| (C.MutCase (_,_,_,outt1,t1,pl1), C.MutCase (_,_,_,outt2,t2,pl2))->
let subst' = fo_unif_aux subst k outt1 outt2 in