Goal:
    x : t  y : t  Heq_anonymous : false = eqb x y  H : x = y
  ============================
   False


DEBUG:Going to execute:
let tac2 H :=
            let ph := fresh "H" in
            let ph' := fresh "H" in
            destruct H as [H ph ph']
           in
           let tacT H := let ph := fresh "X" in
                         destruct H as [H ph] in
           let tacT2 H :=
            let ph := fresh "X" in
            let ph' := fresh "X" in
            destruct H as [H ph ph']
           in
           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