ormolu/data/examples/declaration/class/single-parameters.hs

-- | Something.
class Foo a where foo :: a

-- | Something more.
class Bar a where
    -- | Bar
    bar :: a -> a -> a

class Baz a where
    -- | Baz
    baz ::
        (a,
         a) -- ^ First argument
        -> a -- ^ Second argument
        -> a -- ^ Return value

class BarBaz a where
    barbaz ::
        a -> b
    bazbar :: b -> a