[perl #129128] qualified names in enum keys neither produce error nor work

[via RT]

# New Ticket Created by  Wenzel Peppmeyer 
# Please include the string:  [perl #129128]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=129128 >


enum Collision(<Coll::Str Coll::Int>);
my Collision $c;
dd $c.WHAT.enums; 
$c = Coll::Str;

# OUTPUT«Map.new(("Coll::Int" => 1,"Coll::Str" => 0))␤Could not fin symbol 
'&Str'␤  in block <unit> at <tmp> line 1␤␤AActually thrown ain block <unit> at 
<tmp> line 1␤␤»

# It should either produce an error when the enum is declared or just 
# work.