use strict;
use warnings;
use Data::Dump qw/pp dd/;

sub X::foo { pp(\@_) }; 

BEGIN { *X::baz = sub { pp(\@_) } };


package X;

sub bar { pp(\@_) } ;

foo(1..3);                              # [1, 2, 3]
baz(1..3);                              # [1, 2, 3]

bar(4..6);                              # Undefined subroutine &X::pp called