That does indeed look wrong to me, investigating
> On 23 Mar 2018, at 15:04, Nick Wellnhofer (via RT)
> <perl6-bugs-follo...@perl.org> wrote:
>
> # New Ticket Created by Nick Wellnhofer
> # Please include the string: [perl #133016]
> # in the subject line of all future correspondence about this issue.
> # <URL: https://rt.perl.org/Ticket/Display.html?id=133016 >
>
>
> I get an unexpected result when subtracting a List from a Bag with the set
> difference operator (-). Subtracting Bags from Lists or Bags works fine, as
> does the baggy addition operator:
>
> say bag(<a b>) (+) bag(<a a>); # Bag(a(3), b)
> say bag(<a b>) (+) <a a>; # Bag(a(3), b)
> say <a b> (+) bag(<a a>); # Bag(a(3), b)
>
> say bag(<a a a b>) (-) bag(<a a>); # Bag(a, b)
> say bag(<a a a b>) (-) <a a>; # Bag(a(2), b) seems wrong
> say <a a a b> (-) bag(<a a>); # Bag(a, b)
>
> Only tested online on tio.run
>
> Rakudo version 2017.12 built on MoarVM version 2017.12
> implementing Perl 6.c.
>
> and code-golf.io:
>
> Rakudo version 2018.03 built on MoarVM version 2018.03
> implementing Perl 6.c
>
> Nick
