T6069.hs:13:15:
    Couldn't match type ‘ST s0 Int’ with ‘forall s. ST s a0’
    Expected type: ST s0 Int -> a0
      Actual type: (forall s. ST s a0) -> a0
    In the second argument of ‘(.)’, namely ‘runST’
    In the expression: print . runST

T6069.hs:14:15:
    Couldn't match type ‘ST s1 Int’ with ‘forall s. ST s a1’
    Expected type: ST s1 Int -> a1
      Actual type: (forall s. ST s a1) -> a1
    In the second argument of ‘(.)’, namely ‘runST’
    In the expression: (print . runST)

T6069.hs:15:16:
    Couldn't match type ‘ST s2 Int’ with ‘forall s. ST s a2’
    Expected type: ST s2 Int -> a2
      Actual type: (forall s. ST s a2) -> a2
    In the second argument of ‘(.)’, namely ‘runST’
    In the first argument of ‘($)’, namely ‘(print . runST)’