[perl #127223] Error when smartmatching an empty signature

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# New Ticket Created by  Lucas Buchala 
# Please include the string:  [perl #127223]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=127223 >


> :() ~~ :(Int)
Cannot call 'shift' on an immutable 'List'
  in block <unit> at - line 1

> :(Int).ACCEPTS(:())
Cannot call 'shift' on an immutable 'List'
  in block <unit> at - line 1