let x = []
let x = [1; 2; 3]
let x = [1; 2; 3]
let x = [(1 : int); (2 : int); (3 : int)]
let x = 4 :: 5 :: y
let x = ((Belt.List.concatMany)[@res.spread ]) [|(1 :: x);(2 :: 3 :: x)|]
let x = 1 :: 2 :: (y : int list)