Why does haskell throw this error?

Question

Trying to write function that numerize items of list and returns list of tuples with numbers, ya I know I can do it with 'zip' function, but task is to write it with recursion: so I get

cannot construct an infinite type: a = [a] when generalizing type(s) for numerize'

What am I doing wrong?

numerize' :: [a] -> Int -> [(a, Int)]
numerize' [] _ = []
numerize' [x] n = [(x, n)]
numerize' [x:xs] n = (x, n) : numerize' xs (n + 1)

Answer 1

[x:xs]

should be

(x:xs)