<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/54365>54365</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Bug in either C++17 (maybe 20?) spec, or llvm implementation, shared_ptr
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          timprepscius
      </td>
    </tr>
</table>

<pre>
    Hey there,

I'm not sure where to post this, I feel like I should be posting to some spec committee.  Not sure.

In the Xcode 12.5.1 std memory, there is the snippet:
```

template <class _Tp, class _Alloc>
void
__shared_ptr_emplace<_Tp, _Alloc>::__on_zero_shared() _NOEXCEPT
{
    __data_.second().~_Tp();
}

```

What this snippet does, is when a control block of a shared_ptr detects that there are no more references, it destructs/destroys the object.

Right now the code snippet calls the destructor explicitly, which leaves out the exciting things the allocator might do before destructing the object.

I believe this code snippet should be something like this (writing off the top of my head):

```
using value_allocator = _Alloc::template rebind<the_value_type>::other;
value_allocator allocator;
allocator.destroy(&__data_.second());

```

Or using allocator_traits, or what not.  But in the end, not calling the destructor, but rather using the allocator to call the destructor.

---

If this were the case I could write an allocator which might do something like:

```
void destroy(T *p)
{
  object_is_about_to_be_destroyed_template_function(p);
  other_allocator.destroy(p);
}

```
---

Should I take this issue somewhere else?  Does anyone know who I might talk to about this.

---

There is, of course, a work around, but it isn't pretty, and uses classes which I probably should be using.




</pre>
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