[Haskell-beginners] Point free mystery

[martin]

Helly all

for ad-hoc benchmarking I wrote

bench x = (timeIt . print) x

Hlint suggested

Found:
  bench x = (timeIt . print) x
Why not:
  bench = (timeIt . print)

but when I do this, I get

    No instance for (Show a0) arising from a use of ‘print’

Why is that so?