T6069.hs:13:15:
    Couldn't match type `ST s0 Int' with `forall s. ST s b0'
    Expected type: ST s0 Int -> b0
      Actual type: (forall s. ST s b0) -> b0
    In the second argument of `(.)', namely `runST'
    In the expression: print . runST
    In the expression: (print . runST) fourty_two

T6069.hs:14:15:
    Couldn't match type `ST s1 Int' with `forall s. ST s b1'
    Expected type: ST s1 Int -> b1
      Actual type: (forall s. ST s b1) -> b1
    In the second argument of `(.)', namely `runST'
    In the expression: (print . runST)
    In the expression: (print . runST) $ fourty_two

T6069.hs:15:16:
    Couldn't match type `ST s2 Int' with `forall s. ST s b2'
    Expected type: ST s2 Int -> b2
      Actual type: (forall s. ST s b2) -> b2
    In the second argument of `(.)', namely `runST'
    In the first argument of `($)', namely `(print . runST)'
    In the expression: (print . runST) $