mapM
  :: forall {t :: * -> *} {m :: * -> *} {a} {b}.
     (Traversable t, Monad m) =>
     (a -> m b) -> t a -> m (t b)
mapM
  :: forall (t :: * -> *) (m :: * -> *) a b.
     (Traversable t, Monad m) =>
     (a -> m b) -> t a -> m (t b)
mapM
  :: forall (t :: * -> *) (m :: * -> *) a b.
     (Traversable t, Monad m) =>
     (a -> m b) -> t a -> m (t b)
foo @Int :: forall {b}. Num b => Int -> b
foo @Int :: forall b. (Show Int, Num b) => Int -> b
foo @Int :: forall b. (Show Int, Num b) => Int -> b