Assigning a weakref yields a regular ref, and I think your test isn't quite right. Try (assuming $self/$next are references): 
$self->{next} = $next;
weaken($self->{next}) if $self == $next;

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But that doesn't help with a longer circular chain; you need to pick the one element of the chain that has an external reference and weaken the preceding element's pointer to it.

In reply to Re^2: Q on $var = \$var; by ysth
in thread Q on $var = \$var; by Bastiaan

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