https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80311
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-04-23
Ever confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #0)
> struct X {
> int i = 0;
> int f() { return i; }
> };
>
> int main() {
> X x;
> using fp = int (*)();
> auto f = (fp)(&X::f);
> return f();
> }
>
> This bogus attempt to use
> https://gcc.gnu.org/onlinedocs/gcc/Bound-member-functions.html fails,
> because there is no 'this' pointer provided for the call to the bound
> function.
I should have been clearer about how it "fails".
It compiles (and gives a warning about use of the extension unless you silence
it with -Wno-pmf-conversions) but then segfaults at runtime.
> G++ should notice this and give a diagnostic, even with -Wno-pmf-conversions.
The bug is that we shouldn't accept invalid uses of the extension. Valid uses
of the extension should give warnings that can be controlled by
-Wno-pmf-conversions as happens today, but invalid uses should be an error
(maybe controllable by -fpermissive) not produce code that is guaranteed to
segfault.
