https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102064
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The assignable checks are also missing for C++98, but there are types which can
be constructed via std::uninitialized_foo that cannot be assigned to by
std::foo
#include <memory>
#include <algorithm>
struct X;
struct Y
{
operator X() const;
};
struct X
{
private:
void operator=(const Y&);
};
Y::operator X() const { return X(); }
int main()
{
unsigned char buf[sizeof(X)];
Y y;
std::uninitialized_fill_n((X*)buf, 1, y);
}
This should copy-construct an X from the result of the conversion operator. But
we optimize it to std::fill_n which tries to use the inaccessible assignment.
/usr/include/c++/11/bits/stl_algobase.h:912:18: error: ‘void X::operator=(const
Y&)’ is private within this context
912 | *__first = __value;
| ~~~~~~~~~^~~~~~~~~
