Goal:
    A : Type  B : Type  C : Type  R : A → B → C → Type  H : True
  ============================
   (All3_nil = All3_nil)


DEBUG:Going to execute:
try intros until H; intro_block_id H || intro_block H
Level 5: evaluation returns
try intros until H; intro_block_id H || intro_block H;
 (try simpl in H; DepElim.simplify_equations_in H)
where
H := H
of type
constr of type tacvalue