This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-10-26

2625. Deletion of pointer to out-of-lifetime object

[Accepted as a DR at the November, 2022 meeting.]

Consider:

struct S {};

int main() {
  S* p = new S;
  p->~S();
  delete p;
}

This code appears to be allowed per 6.7.3 [basic.life] bullet 6.1:

The program has undefined behavior if:

• the object will be or was of a class type with a non-trivial destructor and the pointer is used as the operand of a delete-expression,
• ...

However, this calls the (trivial) destructor on *p twice. Invoking a non-static member function of an out-of-lifetime object is generally undefined behavior per 6.7.3 [basic.life] bullet 6.2 and 6.7.3 [basic.life] bullet 7.2. The rules ought to be consistent.

Proposed resolution (approved by CWG 2022-10-07):

Change in 6.7.3 [basic.life] bullet 6.1 as follows:

The program has undefined behavior if:

• the object will be or was of a class type with a non-trivial destructor and the pointer is used as the operand of a delete-expression,
• ...