my $var if $test;

##</code><code>##

my $var = 1 if $test;

##</code><code>##

my $var = 1 if $test;

##</code><code>##

my $value = $1 if $foo =~ /^\w+(\d+)/;
do_something($value) if defined $value;

##</code><code>##

$ perl -Mstrict -Mwarnings -e  ' my $c = 1 if 1; print $c;'
1
~
$ perl -Mstrict -Mwarnings -e  ' my $c if 1; print $c;'
Use of uninitialized value $c in print at -e line 1.


##</code><code>##

my $var = 1 if $test;