New problem compiling g-exctra.adb

[Daniel Berlin]

On Tue, 2004-09-07 at 21:52 -0400, Diego Novillo wrote:
> On Tue, 2004-09-07 at 21:26, Richard Kenner wrote:
> 
> > Why can't we just ignore assignments of pointers to zero?  They would
> > seem to tell us nothing useful about the variable being assigned.
> >
> On the contrary.  If the value 0 tells you that no variable is aliased
> to that pointer, that is invaluable.
> 

Except that you get that information anyway, since there will be no
other assignments to that variable, and thus, ignoring that assignment
will make it unaliased because it points to nothing.
And if there were other assignments for some reason, you have to process
those too, and it could point to those things as well.

Thus, it gives you no information you don't already know, except that
the variable may point to null.