Goal:
  
  A : Type
  B : Type
  C : Type
  D : Type
  R : nat → C → D → Type
  f : nat → A → C
  g : nat → B → D
  n : nat
  ============================
   (All2i R n (mapi_rec f [] n) (mapi_rec g [] n))


DEBUG:Going to execute:
<coq-core.plugins.ltac::constructor@0>
DEBUG LTAC Evaluated term: 0
DEBUG LTAC Evaluated term: h