perl -MO=Deparse,-p -e '$_ = ($x) = (4, 5, 6); print'
($_ = (($x) = (4, 5, 6)));
print($_);
-e syntax OK

##</code><code>##

perl -e '($_ = (($x) = (4, 5, 6)));print'
3#and my shell prompt here of course