Garbage Collector does not need .unmark()

[BenGoldberg1]

This suggestion uses a little extra memory to save a little bit of time.

Change the type of mark from a boolean to an integer, and add an integer gc_count which keeps track of how many times garbage collection has happened.

When marking objects as being accessible, assign the value of gc_count to the 'mark' of every reachable object.

Objects whose mark is not equal to gc_count can be freed.

For objects being kept, the mark can be left as is.

If you come across an object whose mark is not gc_cur or gc_cur-1, panic.

If you think corruption is inconceivable, leave mark as a bool, but on alternate GCs, cycle between assigning true and false to it

[CeleritasCelery]

Hi @BenGoldberg1 , That is a great idea! You could even just use a u8 and keep the mark bit the same size. That would save us from needing to reset the the mark bits each time we are done sweeping. I am in the process of rewriting the garbage collector to be a generational copying version, so this is definitely something I will keep in mind.