Maybe just one extra line like this? Prelude> print 2 + 3 <interactive>:3:1: error: • No instance for (Num (IO ())) arising from a use of ‘+’

Maybe just one extra line like this? Prelude> print 2 + 3 <interactive>:3:1: error: • No instance for (Num (IO ())) arising from a use of ‘+’ • The expression `print 2` :: IO () • In the expression: print 2 + 3 In an equation for ‘it’: it = print 2 + 3 Just adding the one line telling telling you what was `IO ()` is helpful. ghci obviously knows what it was here.