OCL25 — OCL 2.3 Collecting elemental collections

collect and collectNested have irregular semantics that ignore the natural (outer) collection element type when used on nested collections:

i.e Set{Set{1.0}}>collect(toString()) is Set{Set{1.0}}>collect(s : String | s.toString())

so how might an iteration over the outer collection element type be performed?

Presumably, for homegeneous collections, by explicitly specifying the iterator type as Set{Set{1.0}}>collect(s : Set(String) | s>size())

Suggest: collect, collectNested specify that the implicit iterator type is the innermost collection type, and that an explicit type may
specify a collection type that successfully iterates when all leaves of the tree are uniquely contained in a corrsponding iteration element
of the iterator type, else the iteration is invalid.

Can't see a solution for heterogeneous solutions