Re: Conservative GC isn't safe

[Eli Zaretskii]

> From: Daniel Colascione <address@hidden>
> Date: Sat, 26 Nov 2016 00:33:13 -0800
> 
> >>   2) INTERVAL is GCed, but it's not represented in the memory tree:
> >> struct interval isn't a real lisp object and it's allocated as
> >> MEM_TYPE_NON_LISP. Even a direct pointer to the start of an interval
> >> won't protect it from GC. Shouldn't we treat intervals like conses?
> >
> > Does the code ever create an interval that is accessible only via locals
> > when a GC occurs? If not, Emacs should be OK. (This should also be
> > documented better.)
> 
> Anywhere in the code? Forever? I wouldn't be confident saying so.

A simple practical solution to such assumptions is to add an assertion
in some strategic place(s).

I don't think it's TRT to sprinkle our sources with code that is there
"just in case", i.e. it will never actually run.