data N : U where
| Z : ...
| S : (_:N) -> ...
data False : U where
data Id {A : U} : (x y : A) -> U where
| refl : (t : A) -> ... t t
fun what (add : N -> N -> N) (_ : Id (add Z Z) Z) : False where
| _ k !@ k
Adding a new state for unification in pattern matching part, when unifying VCon with a non VCon. In this situation, we are not sure if it possible to use absurd pattern.