D:\Development>perl -MO=Deparse -e "use strict; my $x=1; my $y=1 if $x; print $x.' '.$y;"
my $x = 1;
my $y = 1 if $x;
print $x . ' ' . $y;
-e syntax OK

D:\Development>perl -MO=Deparse -e "use strict; my $x=10; my $y=$x while ($x--); print $x.' '.$y"
my $x = 10;
my $y = $_ while $x--;
print $x . ' ' . $y;
-e syntax OK