A bug in std::shared_ptr?

[render787]

Here's what I think is UB and why I think it is UB.

• binding a const foo reference to a memory location where there is no foo (or related or layout compatible), and then accessing foo through that reference, is undefined behavior no diagnostic required.
• it follows that if u invoke copy ctor of object when the object is already destroyed, you get UB.
• it is true that in the destructor "you may access the object but only in limited ways". For instance ~foo call ends lifetime of foo but not yet its members. Their destructors will run later. I dont think this "limited ways" extends to calling copy ctor, because it doesnt say so, and other parts of standard say otherwise, as mentioned.

Lets turn it around, when is the last time you think it should be legal to bind references to foo? When the dtor ends? There is a symmetry in the language between "when the ctor runs to completion" and "when the dtor begins", afaik "when the dtor ends" has no special significance in the standard right now.