use strict;
use warnings;

use Clone qw(clone);
use Data::Dumper;

my $str;
$str .= "{ $_ => " for 'a'..'z';
$str .= '}' x 26;

my $orig = {
   nested_hash => eval $str,
   code_ref    => sub { my $foo = 'bar'; sub{$foo} },
};

my $clone = clone($orig);
print Dumper $clone->{nested_hash};

print $clone->{code_ref}->()->(), $/;