:info (->) should list its fixity
The GHC manual states:
- Function arrow is
infixrwith fixity 0. (This might change; I'm not sure what it should be.)
Since this isn't the default
infixl 9, it should be listed when you do
:info (->), but currently (at least in 7.8.3) isn't.
(Inspired by this Stackoverflow question.)