DIP74 & GC Destructors

[rsw0x via Digitalmars-d]

Andrei mentioned work on reference counting recently so I'm 
assuming there's still plans on implementing DIP74¹.

With reference counted objects built into the language, it might 
be worth investigating dropping destructors from all non-RC'd GC 
allocated objects for a complete separation of objects that 
control resources and need finalization, and objects that do not.

The current destructor implementation is incredibly bug prone, 
and is often almost always misused. It has already been made 
quite clear that you _can not_ rely on the GC for releasing 
resources². The current GC is even non-reentrant³, meaning that 
you can't allocate in destructors. You also have to assume any 
other reference to heap-allocated memory is in an undefined state 
during a destructor, further limiting their usefulness.

Furthermore, not having to worry at all about destructors would 
improve the performance of the GC. The GC could just mark large 
blocks of memory as free without having to scan which blocks of 
memory have destructors, which can slow down sweeping(I have yet 
to do any sort of testing on this, it is just a theory.)

One of the main concerns when choosing D as a language is the GC 
performance, I think this is a well accepted fact. It's worth 
evaluating anything that might improve the performance of the GC 
in my opinion.

Bye.

¹ - http://wiki.dlang.org/DIP74
² - http://dlang.org/class.html#Destructor "... The garbage 
collector is not guaranteed to run the destructor for all 
unreferenced objects"
³ - 
http://dlang.org/phobos/core_exception.html#.InvalidMemoryOperationError