open import Agda.Builtin.Nat using (Nat; suc; zero)
open import Agda.Builtin.List

double : Nat  Nat
double zero = zero
double (suc x) = suc (suc (double x))

xs : List Nat
xs = 1  3  5  []

map : {A B : Set} -> (A  B)  List A  List B
map f [] = []
map f (x  xs) = f x  map f xs

ys : List Nat
ys = map double xs
{-# COMPILE AGDA2LAMBOX ys #-}
Debug λ☐ Rocq