[perl #127050] postfix:<++> stips mixins

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# New Ticket Created by  Wenzel Peppmeyer 
# Please include the string:  [perl #127050]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=127050 >


role R { method Str() {'hidden!'} };
my $i = 1 but R;
sub f(\bound){ put bound };
f($i);
$i++;
f($i);

# OUTPUT«hidden!␤2␤»