Goal:
    x : V.t  n : Z  y : V.t  H : V.eq x x /\ n = n /\ V.lt y y
  ============================
   False


DEBUG:Going to execute:
match goal with
           | |- ?X1 -> ?X2 => intro
           | |- ~ _ => unfold not at 1; intro
           end
Level 0: Backtrace:

No matching clauses for match.