If I recall correctly, there has been talk about fixing this so my $x ... if ... acts like my $x; $x ... if .... I originally had a negative reaction to that, since the my $x if 0 had been advocated by some as a valid way to produce a semi-static variable, but now, given that that warning has been in the doc since 5.8.0, I think its a good idea. People mess themselves up by accident too much to care about those intentionally doing it. (The doc warning should probably be added to 5.6.2, also.)