package Cls;
use Moose;

has an_array => (
    traits  => ['Array'],
    isa     => 'ArrayRef[Str]',
    is      => 'rw',
    # !!! forgotten default to empty array
    handles => {
        list_array => 'elements',
        add_item   => 'push',
    },
);

package main;

func();

sub func {
    my $c = Cls->new();
    $c->add_item('String');
}

##</code><code>##

package MooseX::Silent;

use Carp qw(confess);

$Carp::Internal{$_}++ for qw{
    MooseX::Silent
    MooseX::Method::Signatures::Meta::Method
    Moose::Meta::Attribute::Native::MethodProvider::Hash
    Moose::Meta::Attribute::Native::MethodProvider::Array
    Moose::Meta::Attribute::Native::Trait
};

$SIG{'__DIE__'} = sub { 
    my $msg = shift;
    for($msg) { 
        s/^.*Internal Validation Error is: //; 
        s/MooseX::Types::Structured:://g; 
        s/ at .*? line \d*\.//;
        chomp;
    }
    confess "$msg";
};

1;

##</code><code>##

Can't use an undefined value as an ARRAY reference at tst.pl line 22
	main::func() called at tst.pl line 18