A class declares an attribute of type `expanded A', where A contains
an attribute of type `expanded B' (a sub-object).  Neither classes A
nor B are themselves expanded.  Class B has a function which returns
`Current' as its result.  It appears that a caller is able to get and
save a reference to a sub-object.  Wasting memory to cause a garbage
collection then causes execution to terminate with a run-time panic.

Discovered in Release 3.2.2.