Goal:
    x : byte  y : byte  Hcomp : Some x = Some y
  ============================
   (let H := CoreTactics.block in let H0 := CoreTactics.block in x = y)


DEBUG:Going to execute:
<coq-core.plugins.ltac::revert@0> $1
Level 3: evaluation returns
revert H'
where
H' := Hcomp
of type
constr
H := Hcomp
of type
constr of type tacvalue