use strict;
use warnings;

my $cond=1;
my $i=1 for $cond;
for ($cond) {
    my $j=1;
}
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(called as perl -MO=Deparse cond.pl) We got the following:

my $cond = 1;
foreach $_ ($cond) {
    my $i = 1;
}
foreach $_ ($cond) {
    my $j = 1;
}
[download]

Which is of course _wrong_. My colleague used this to supposedly _prove_ that the modifier form is identical to the non-modifier form. I disagreed but had nowhere to go until we appended the following lines to the original script and then uncommented them one at a time. Guess which ones fail

#comments added on update
#print "$i/n";      # Works for input code, not output code
#print "$j/n";      # Fails for both
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Begin Update
I should have been more specific. The point here is the original two loops have different scoping effects. But, I presume because the output of deparse is from a stage after these effects are determined. I dont know and I'd like to understand it better. End Update