| Issue |
61562
|
| Summary |
Destroying an object during a call to construct_at erroneously rejected during constant evaluation
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
davidstone
|
The following valid (I think) translation unit
```cpp
#include <memory>
struct ref_holder {
constexpr explicit ref_holder(int & value):
m_value(value)
{
}
constexpr operator int() const {
using T = int;
m_value.~T();
return int();
}
private:
int & m_value;
};
constexpr bool f() {
int x = 0;
std::construct_at(&x, ref_holder(x));
return true;
}
static_assert(f());
```
is rejected by clang with
```console
<source>:25:15: error: static assertion _expression_ is not an integral constant _expression_
static_assert(f());
^~~
<source>:11:3: note: destruction of object outside its lifetime is not allowed in a constant _expression_
m_value.~T();
^
/opt/compiler-explorer/clang-assertions-trunk-20230319/bin/../include/c++/v1/__memory/construct_at.h:38:50: note: in call to '&ref_holder(x)->operator int()'
return ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...);
^
<source>:21:2: note: in call to 'construct_at(&x, ref_holder(x))'
std::construct_at(&x, ref_holder(x));
^
<source>:25:15: note: in call to 'f()'
static_assert(f());
^
1 error generated.
Compiler returned: 1
```
See it live: https://godbolt.org/z/T6Wo6rd6d
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