Goal:
  
  A : Type
  B : Type
  R : A → B → Type
  R' : ∀ (a : A) (b : B), R a b → Type
  e : True
  ============================
   (noConfusionHom_All2_dep_obligation_2 A B R R' [] [] All2_nil All2_dep_nil
      All2_dep_nil
      (noConfusionHom_All2_dep_obligation_1 A B R R' [] [] All2_nil
         All2_dep_nil All2_dep_nil e) = e)


DEBUG:Going to execute:
match type of H with
           | ?R ?x ?y =>
               let rhs := fresh in
               set (rhs := y) in *; pattern sigma rhs; clearbody rhs;
                destruct H; simpl
           end