package Foo;

sub new { bless {} => shift }
sub baz { "Hello from Foo::baz" } 

package Bar;
use base 'Foo';

sub baz { # baz is private ...
   my $caller = caller;
   croak "Can't call private method from $caller"
      if $caller ne __PACKAGE__;
   "Hello from Bar::baz (private)";
}

sub call_baz { (shift)->baz }

package main;

Bar->new->baz; # BOOM!


##</code><code>##

package Foo;

sub new { bless {} => shift }
sub baz { "Hello from Foo::baz" } 

package Bar;
use base 'Foo';

my $baz = sub { # baz is private ...
   my $caller = caller;
   croak "Can't call private method from $caller"
      if $caller ne __PACKAGE__;
   "Hello from Bar::baz (private)";
};

sub call_baz { (shift)->$baz() }

package main;

Bar->new->baz; # no more BOOM!