Pass a function call that returns a value:

Notice: Only variables should be passed by reference in %s on line 44
string(8) "original"
string(8) "original"
Pass a function call that returns a reference:
string(8) "original"
string(7) "changed"

Pass a static method call that returns a value:

Notice: Only variables should be passed by reference in %s on line 55
string(8) "original"
string(8) "original"
Pass a static method call that returns a reference:
string(8) "original"
string(7) "changed"

Pass a method call that returns a value:

Notice: Only variables should be passed by reference in %s on line 67
string(8) "original"
string(8) "original"
Pass a method call that returns a reference:
string(8) "original"
string(7) "changed"