foo.p6

sub MAIN (*@sz) {
    for @sz -> $sz {
        my int @a = ^$sz;
        my $s = @a.sum;
        my $w = @a.sum(:wrap);
        printf "%d : %10d %s %d\n",
            $sz,
            $s,
            ($s == $w ?? '==' !! '!='),
            $w,
        ;
    }
}

# --------------------------------------------------------------------
=finish

This program was inspired by a failing test in <./t/08-performance/99-misc.t>

"This is Rakudo version 2019.03.1-422-g672fd6e2c built on MoarVM version 2019.05-11-g248e2980a implementing Perl 6.d."
(2019-05-21).

I'm on a 32-bit system.

As expected:

    ▸ foo.p6 65536 65536
      65536 : 2147450880 == 2147450880
      65536 : 2147450880 == 2147450880

Hmm... 65537 is wrong with a plain sum(), but succeeds with ':wrap' (I
kind of expected the opposite):

    ▸ foo.p6 65536 65537
      65536 : 2147450880 == 2147450880
      65537 :  268468224 != 2147516416

Wut? First attempt gets both correct?

    ▸ foo.p6 65537 65537
      65537 : 2147516416 == 2147516416
      65537 :  268468224 != 2147516416