T6069.hs:13:15: error:
    • Couldn't match type: forall s. ST s b0
                     with: ST s0 Int
      Expected: ST s0 Int -> b0
        Actual: (forall s. ST s b0) -> b0
    • In the second argument of ‘(.)’, namely ‘runST’
      In the expression: (print . runST) fourty_two
      In an equation for ‘f1’: f1 = (print . runST) fourty_two

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

T6069.hs:15:16: error:
    • Couldn't match type: forall s. ST s b2
                     with: ST s2 Int
      Expected: ST s2 Int -> b2
        Actual: (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) $