As ikegami pointed out, the second form does not work as probably intended (this was actually a new one on me!) But how about this version?

if (1 and ($result = (func($param))[0])) {
   print "1\n";
} else {
   print "0\n";
}
print "$result\n";

sub func { return (0, 1, 2); }
[download]

Prints two 0's, which seems to be what is wanted here - and with syntax that makes more direct sense than form #1 (at least in my opinion).