You called $x a lexical, but that's only semi-true. $x is aliased to undef, so $x is whatever undef returns.

When a LHS element of a list assignment is undef*, Perl apparently creates an SV to contain the assigned value. These are returned by the list assignment, and these are the values you are dumping for the first and third pass of the inner loop.

There doesn't seem to be anything special about the loop wrt undefined values. It seems to be the list assignment creating the new SVs.

* — Probably not any undefined value, just those that look like they were returned by undef.

In reply to Re: list assignment and undef (deduction) by ikegami
in thread list assignment and undef by ig

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