the output like this:

use warnings;
use strict 'refs';
(my $heap = {});
($$heap{'172.16'} = 1);
print("\$heap->{'172.16'}: $$heap{'172.16'}\n");
print("\$heap->{172.16}: $$heap{172.16}\n");
($$heap{'127.2'}{'127.1.0.2'} = 2);
print("\$heap->{'127.2'}{'127.1.0.2'}: $$heap{'127.2'}{'127.1.0.2'}\n"
+);
print("\$heap->{127.2}{127.1.0.2}: $$heap{127.2}{127.1.0.2}\n");
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and have the same executed result:

$heap->{'172.16'}: 1
$heap->{172.16}: 1
$heap->{'127.2'}{'127.1.0.2'}: 2
Use of uninitialized value in concatenation (.) or string at testHash3
+.pl line 25.
$heap->{127.2}{127.1.0.2}:
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