Re: int/Lisp_Object mixup

[Stefan Monnier]

> Is there any reason why developers shouldn't just _always_ use it?
> Does it slow down emacs greatly?

USE_LISP_UNION_TYPE offers no additional checking during execution
(i.e. it is only useful during compilation).  On the reverse side, it does
slow things down (tho not excessively so) and (more importantly for me) it
makes backtraces very verbose.
I.e. it's good to compile with it every once in a while, but for actual
execution it's more important to use ENABLE_CHECKING.


        Stefan