[perl #128321] Int.Capture is empty

[via RT]

# New Ticket Created by  Wenzel Peppmeyer 
# Please include the string:  [perl #128321]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=128321 >


dd 10.Capture, 0.5.Capture;
# OUTPUT«\()␤\(:denominator(2), :numerator(1))␤»
# expected OUTPUT«\(10)␤\(:denominator(2), :numerator(1))␤»

# this leads to odd behaviour for

sub returns-different-things () { ((10,"ten"), 10).pick };
given returns-different-things() {
     when :(Int, Str) { say 'It returned a list.' };
     when :(Int) { say 'returned a single Int' };
     default { say 'This should never happen' }
}

# OUTPUT«This should never happen␤»