int x;
new (storage) std::byte[sizeof(x)];              // implicitly begin the lifetime of objects in x
*reinterpret_cast<char*>(&x);                    // unspecified whether placement new created
                                                 // an int object inside x, float, char[], or any other objects

std::memmove(&x, &x, sizeof(x));                 // transparently replace ([basic.life]) x with another object
x = 0;                                           // the new object must be of type (no cv) int because 
                                                 // only that may give the program well-defined behavior

std::memmove(&x, &x, sizeof(x));                 // begin the lifetime of one or multiple objects in the storage of x
std::launder(reinterpret_cast<short*>(&x));      // created object at &x must be of type short int
x = 0;                                           // undefined behavior