PATCH RFA: PR 29286: Handle placement new aliasing issues

[Richard Kenner]

> I agree that in principle this could be done using type variants.  But
> in practice I think it is more reliable to make it a property of the
> pointer rather than of the type of the pointer.

What do you mean?  Suppose I have a function returning such a pointer.
Where is the "property"?  Don't these things *have* to be on the type?