---> 1. Trying to assign by reference the return value of a function that returns by value:
int(5)
int(100)

---> 2. Trying to assign by reference the return value of a function that returns a constant by ref:
int(5)
int(100)

---> 3. Trying to assign by reference the return value of a function that returns by ref:
int(5)
int(5)