While developing a debugging aid, I stumbled across some untie behavior that seemed odd until pondered for a bit (leading to a "d'oh!" moment). Here is a stripped-down example. Can you predict what this script will print? 

use strict;

package Object;

sub new {
  bless {}, "Object"
}

sub foo { "ObjectFoo\n" }

package Tied;

sub TIESCALAR {
    my $class = shift;
    my $o = shift;
    bless \$o, $class;
}

sub FETCH {
    my $self = shift;
    print "<fetch>\n";
    $self
}

sub foo { "TiedFoo\n" }

package main;

my $o = new Object();
print $o->foo();

tie $o, 'Tied';
print $o->foo();

untie $o;
eval { print $o->foo() };
print "NoFoo\n" if $@;

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In reply to The aftermath of an untie by dws

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