§1.5.(b) Nested classes of roles

A regular role class (ie., not marked as team, see above) may contain local types (see JLS §14.3 - in the example: class Local), anonymous types (JLS §15.9.5 - in the example: class defined in lines 18-20) but no member types (JLS §8.5 - in the example: illegal class IllegalMember).
The effect is, that nested types of a regular role cannot be used outside the scope of their enclosing role.