This is a real issue that bites people from time to time, and it seems to me that it could be fixed with a minor extension of syntax to specify that a foreach loop should not do aliasing. Of course, it can also be addressed by a little code (and awareness): 
my $n; # Going to set this
for my $a (1..100) {
    if ($a == 50) {
        $n = $a;
        last;
    }
}
# $n is 50

[download]
The advantage to new syntax would be that it promotes awareness of the two non-compatible WIMs. It could also have the ever-so-slight advantage of reducing the number of variables declared. I've thought of three possible syntax extensions:
  1. An alias pragma, on by default: 
    no alias;
for $n (1..100)

    [download]
  2. The addition of an equals sign to indicate that each element is assigned, rather than aliased: 
    for $n = (1..100)

    [download]
  3. Using a ref to a scalar var instead of a scalar var to indicate non-localization: 
    for \$n (1..100)

    [download]
None of these would affect existing code (unless there's already an alias module/pragma of which I'm unaware).
The PerlMonk tr/// Advocate

In reply to Re^2^2: for loop localisation bug? by Roy Johnson
in thread for loop localisation bug? by BrowserUk

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.