<$0.02>

When I'm doing something so simple that Moo is more than I need, I usually turn to Class::Accessor::Fast. You could easily copy the source from Class::Accessor and/or Class::Accessor::Fast if you really can't install modules from CPAN.

package Foo;
use strict; use warnings;
use parent 'Class::Accessor::Fast';

BEGIN {
    __PACKAGE__->mk_accessors(qw/ bar qux /);
}

sub new {
    my $class = shift;
    return $class->SUPER::new();
}

1; # return true
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perl -MFoo -E'
my $foo = Foo->new;
$foo->bar("baz");
$foo->qux( $foo->bar );
say $foo->bar;
say $foo->qux;
'
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Output:

baz
baz
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