T16059a.hs:8:6: error:
    • Illegal constraint in a kind: Eq b => b
    • In the type signature: f :: forall b (a :: Eq b => b). Int

T16059a.hs:11:6: error:
    • Illegal constraint in a kind: Eq b => b
    • In the expansion of type synonym ‘Foo’
      In the type signature: g :: forall b (a :: Foo b). Int