Goal:
    a : byte  b : byte  e : NoConfusion_byte a b
  ============================
   (noConfusion_byte_obligation_2 a b (noConfusion_byte_obligation_1 a b e) =
    e)


DEBUG:Going to execute:
match goal with
           | H:exists y, _ y |- _ => tac H
           | H:{x : _ | ?P x} |- _ => tac H
           | H:{x : _ & ?P x} |- _ => tacT H
           | H:exists2 x : _, _ x & _ x |- _ => tac2 H
           | H:{x : _ | ?P x & _ x} |- _ => tac2 H
           | H:{x : _ & ?P x & _ x} |- _ => tacT2 H
           end