
tcfail168.hs:8:11:
    Couldn't match expected type `Char -> a0' with actual type `IO ()'
    In the return type of a call of `putChar'
    Probable cause: `putChar' is applied to too many arguments
    In a stmt of a 'do' block: putChar 'a'
    In the expression:
      do { putChar;
           putChar 'a';
           putChar 'a';
           putChar 'a';
           .... }
