[Bug libstdc++/112591] variant allows for creating multiple empty objects at same address

[tkaminsk at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112591

--- Comment #6 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
If you consider:
struct A{};
struct B:A{char buf[4];};

And then, following
B b;
auto p = new(b.buf) A();

Then static_cast<A*>(&b) and p have the same address. And again *p is only
nested within b.buf. So I believe the nested within wording for variant is
meant to allow implementation based on char buffer.