No, the problem is that $k is not available (slightly different than garbage collected). It is included in the closure, as this demonstrates: 
use strict;
use warnings;

$::clos = $::clos = "global";

sub foo {
   my $clos = shift;
   my $sub = shift;
   &$sub() if $sub;
   return sub {
      eval 'print "$clos\n"'
   }
}

foo("baz", foo("bar"));

[download]
The first (inside) call to foo returns a closure on foo's $clos. The second call to foo calls the closure, which does get the closed-over $clos. But there is a problem: entering foo the second time reuses the same lexical $clos, since perl isn't aware that the first call will be referring to it, so as an optimization doesn't bother allocating a new lexical.

Note that in 5.10.0, the OP's problem code gives a warning: 

Variable "$k" is not available at (eval 1) line 1.

[download]
--
Online Fortune Cookie Search

In reply to Re^2: Scope problem in closures with an eval statement by ysth
in thread Scope problem in closures with an eval statement by citromatik

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.