---> 1. Via a return by ref function call, assign by reference the return value of a function that returns by value:

Notice: Only variable references should be returned by reference in %s on line 16
int(5)
int(100)

---> 2. Via a return by ref function call, assign by reference the return value of a function that returns a constant by ref:

Notice: Only variable references should be returned by reference in %s on line 8
int(5)
int(100)

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