wstring runtime failure - likely bug in swprintf

The following test fails:
#include <cstdlib>
#include <cwchar>
#include <string>
#include <limits>

void compare(long long i) {
std::wstring g = std::to_wstring;
wchar_t buf[200];
std::swprintf(buf, 200, L"%lld", i);
std::wstring x(buf);
if (g != x)

}

int main( void )