Is “rebinding” references in C++ like this legal?

Question

Is the following legal in C++?

As far as I can tell, Reference has a trivial destructor, so it should be legal.
But I thought references can\'t be r

Answer 1

There is no reference being rebound in your example. The first reference (constructed on line two with the name r.r) is bound to the int denoted by x for the entire of its lifetime. This reference's lifetime is ended when the storage for its containing object is re-used by the placement new expression on line three. The replacement object contains a reference which is bound y for its entire lifetime which lasts until the end of its scope - the end of main.