use diagnostics;

0->my_method();

__DATA__
Can't call method "my_method" without a package or object reference at

    (F) You used the syntax of a method call, but the slot filled by the
    object reference or package name contains an expression that returns a
    defined value which is neither an object reference nor a package name.
    Something like this will reproduce the error:
    
        $BADREF = 42;
        process $BADREF 1,2,3;
        $BADREF->process(1,2,3);
    
Uncaught exception from user code:
	Can't call method "my_method" without a package or object reference at script line 3