perl -E"$x=chr(0); $x x= 100e6; <>; $r = \substr $x, 50e6; <>"

##</code><code>##

my $ref;
{
    my $string = "123";
    $ref = \$string;
}

## Here $string persists.

##</code><code>##

my $ref;
{
    my $string = "123";
    $ref = \substr $string, 1, 1;
}

## This was the (IMO false) "bug" scenario.