use 5.010;
use strict;
use warnings;

$SIG{__WARN__} = sub {
    my $w = shift;
    if ($w !~ /uninitialized/){
        warn $w;
    }
};

my $x = 23;
my $y;

debug("x='$x' y='$y'");

sub debug { 
    say shift; 
}