It is unrelated to eval, and truly is a WTF moment , and it prints PerlIO.pm.

I've confirmed on win32 with perl v5.8.9, v5.10.0, v5.10.1

#!/usr/bin/perl --
use strict;
use warnings;
close(STDIN);
open( STDIN, '<', \my $stdin ) or die "$!\n$^E";
my $script_input = 'blah';
$stdin .= $script_input;
while (<>) {
    print;
}
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