https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80711
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #2)
> Also useful would be to warn for members that don't access any state at all:
>
> struct indirect_cmp {
> bool operator()(const X* l, const X* r) { return *l < *r; }
> };
>
> This comparison object should have a const-qualified member function to be
> usable with associative containers such as std::set (see PR 83102 for
> example).
If I extend this to modify global state it's not pure, but should still be
const-qualified:
struct indirect_cmp {
static int counter;
bool operator()(const X* l, const X* r) {
++counter;
return *l < *r;
}
};
int indirect_cmp::counter = 0;
So the pure attribute isn't the right property.
