Hi,

Symbol GC might cause two problems: (1) GC throughput decreased. (2)
possible incompatibility.

Most programs do not consume many symbols that need to be collected.
Symbol GC we need to scan more values, that introduce more scan time.

Besides that, some programs convert symbols and integers back and
force.  These programs might not work if symbol GC introduced.

I don't say I am totally against symbol GC, but it's more
controversial than you might think at first glance.

							matz.