Q:

How can I set up Haskell's GHCI to interactively evaluate functions to their signature (type) instead of getting errors? 

To see the function's signature in Haskell GHCI, I have to prefix it with :t:
Prelude> f = \x -> x+1
Prelude> :t f
f :: Num a => a -> a

But typing that prefix every time grows quickly old.  If I leave it out, I get error:
Prelude> f

<interactive>:5:1: error:
• No instance for (Show (a0 -> a0)) arising from a use of ‘print’
    (maybe you haven't applied a function to enough arguments?) 
• In the first argument of ‘print’, namely ‘it’
  In a stmt of an interactive GHCi command: print it

Instead of getting this error message, I would like see some useful information about my function f similar to the one I get with :t f (possibly even more information about f). 
How can I set up the GHCI to achieve this functionality, i.e. getting function's info upon entering it without :t? 

A:

You probably can't do this today.  I've opened a feature request to see about adding options to control what GHCi reports about type errors at the prompt.