precise GC

[KnightMare]

/* English is not my native, and I tried to use Google translate. 
I hope u will understand subtleties of questions */

For precise-GC:

3) closures: do the closures have any internal types that helps 
to GC or are they (full closure memory block) scanned as in the 
conservative mode?

4) associative arrays:
SomeTypeWithRefsToClasses[string]
any pair will be allocated at some memory block [hash, key, 
value] as I imagine.
Will be precise-GC scan at every pair block only some fields of 
SomeTypeWithRefsToClasses or full [pair-block]?
will be scanned string-key memory block: span-struct and\or chars 
data?