Goal:
    A : Type  B : Type  C : Type  R : A → B → C → Type  e : True
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    noConfusionHom_All3_obligation_2 A B C R [] [] [] All3_nil All3_nil
      (noConfusionHom_All3_obligation_1 A B C R [] [] [] All3_nil All3_nil e) =
    e)


DEBUG:Going to execute:
fun p =>
             DepElim.introduce p;
              DepElim.elim_case p || destruct p || (case p; clear p)