a few examples that I don't think Perl::Critic or any of its extensions covers 
my $x;
foreach $x () {}

[download]
I uploaded your 2 lines of code to the free Perl::Critic website, http://perlcritic.com/, and it produces this message: 
Loop iterator is not lexical at line 2, column 1.  See page 108 of PBP
+.  Severity: 5

[download]
It even has a link to the verbose explanation of the message, complete with advice on how to re-code it. Therefore, Perl::Critic does indeed detect this coding style.

I know Perl::Critic is configurable, and I would not be surprised to find out that it is also extensible.

In reply to Re: The maybe it is better written this way tool by toolic
in thread The maybe it is better written this way tool by szabgab

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.