use feature qw( say );
use Data::Alias qw( alias );

sub concat { my $lhs = shift; my $rhs = shift; $lhs . $rhs }

{
   my $foo = "weird123";
   alias push @_, $foo;
   $foo =~ s/123//;
   alias push @_, $foo;
   alias push @_, &concat;
   say shift(@_);
}