cos-list-of-atomic: In the definition of list type 'aa....aa', type 'bb....bb' is an invalid list element type because it is not atomic ('bb....bb' is either a list type, or a union type which contains a list).

In the definition of the list type aa....aa, the type bb....bb is an invalid list element type because it is not atomic (bb....bb is either a list type or a union type that contains a list).