"Stopped in , _exception :: e = _ Logged breakpoint at QSort.hs:6:32-34 _result :: Char -> Bool a :: Char Logged breakpoint at QSort.hs:6:24-38 _result :: [Char] a :: Char as :: [Char] Printing 1 as = 'b' : 'c' : (_t1::[Char]) Forcing *** Exception: Prelude.undefined CallStack (from HasCallStack): undefined, called at :3:17 in interactive:Ghci1 Printing 2 as = 'b' : 'c' : (_t2::[Char])