use Types::Standard qw(Int Num);
   
   my $RoundedInt = Int->plus_coercions( Num, 'int $_' ); 
   tie(my @numbers, $RoundedInt);
   
   push @numbers, 1, 2, 3;     # ok
   push @numbers, 4.2;         # rounded to 4
   push @numbers, "five";      # dies