[perl #112910] enum mixin leads to non-transitive type checking

[via RT]

# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #112910]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=112910 >


< moritz> r: enum A <b c>; say b ~~ A
<+p6eval> rakudo 2ac569: OUTPUT«True␤»
< moritz> r: enum A <b c>; say ("foo" but b) ~~ A
<+p6eval> rakudo 2ac569: OUTPUT«False␤»
< moritz> r: enum A <b c>; say ("foo" but b) ~~ b
<+p6eval> rakudo 2ac569: OUTPUT«True␤»
< moritz> wait. b ~~ A, but ("foo" but b) ~~ b  and ("foo" but b) !~~ A?
< moritz> that seems... odd
< moritz> I kinda thought our type system was transitive :-)
 * moritz submits rakudobug