[perl #75302] Assignment to 'is copy' parameter which holds Whatever has no effect

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# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #75302]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=75302 >


Can't clear a variable that holds *:

22:21 <@moritz_> rakudo: sub f($x is copy) {  $x = 'abc'; say $x.WHAT;
say $x.perl }; f *
22:21 <+p6eval> rakudo eb84e9: OUTPUT«Whatever()␤!whatever_dispatch_helper␤»


Behaves as expected

22:20 <@moritz_> rakudo: sub f($x is copy) {  $x = Any; say $x.defined;
say $x.perl }; f 'a'
22:20 <+p6eval> rakudo eb84e9: OUTPUT«0␤Any␤»

Also behaves as expected:

22:20 <@moritz_> rakudo: my $x = *; $x = Any; say $x.perl
22:20 <+p6eval> rakudo eb84e9: OUTPUT«Any␤»