fourmolu-0.0.6.0: data/examples/declaration/class/super-classes.hs

class () => Foo a
class Foo a  => Bar a
class (Foo a,Bar a) =>
      Baz a
class (
    Foo a, -- Foo?
    Bar a, -- Bar?
    Baz a  -- Baz
  ) => BarBar a