Why can I assign something to rValue string?

Question

As I expected this code doesn't compile because move gives you rValue and you can't assign anything to rValue:

int a, b;
move(a) = b;

The question is why below code compiles?

string a, b;
move(a) = b;

Answer 1

The reason is a bit surpring, probably. The first form is the built-in assignment, and that indeed does not work on rvalue references.

The second statement is actually move(a).operator=(b). That is a function call. You can call functions on rvalues, even if the functions have somewhat unusual names.