compose (C:=nat) S
     : (nat -> nat) -> nat -> nat
ex_intro (P:=fun _ : nat => True) (x:=0) I
     : ex (fun _ : nat => True)
d2 = fun x : nat => d1 (y:=x)
     : forall x x0 : nat, x0 = x -> x0 = x

Arguments x, x0 are implicit
Argument scopes are [nat_scope nat_scope _]
map id (1 :: nil)
     : list nat
map id' (1 :: nil)
     : list nat
map (id'' (A:=nat)) (1 :: nil)
     : list nat