/// A list of region bounds on the (implicit) self type. So if you
/// had `T: 'a + 'b` this might would be a list `['a, 'b]` (but
/// the `T` is not explicitly included).
/// A list of region bounds on the (implicit) self type. So if you
/// had `T: 'a + 'b` this might would be a list `['a, 'b]` (but
/// the `T` is not explicitly included).