Huh - how can that work? Take some partially evaluated object 'F <thunk>', where F is a data constructor. This object is old and thus stored in the oldest gen

Huh - how can that work? Take some partially evaluated object 'F <thunk>', where F is a data constructor. This object is old and thus stored in the oldest generation. When we force the thunk, we have to update the reference in the object to point to the resulting value - which, as it is newly allocated, should be in the nursery. Is the trick simply to allocate in whichever generation our referencing pointer belongs? As I see it, the basic problem is that lazy evaluation requires mutation at the heap-level.