[Bug c++/81928] if(!this) optimization leads to possible errors without warnings

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81928

--- Comment #22 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No, comment 1 was from Richard. And the warning already exists, and it says
that a nonnull argument (i.e. something that can never be null) is compared to
null. The only thing I'd change would be to change 'argument' to 'pointer'.

Please stop reopening this to ask for the same thing, you're making yourself
look silly.

Either explain more clearly what you're asking for, or accept it already warns
about this.