Goal:
    G : t  HI : invariants  A : Prop  B : Prop  b : B  H : A  H1 : B
  ============================
   A


DEBUG:Going to execute:
match reverse goal with
           | |- ?X1 => <Coq.Init.Tauto.is_unit_or_eq> flags X1; constructor 1
           | H:?X1 |- _ => <Coq.Init.Tauto.is_empty> flags X1; elim H
           | _ => Ltac.assumption
           end