[perl #81278] Can't defer to return()

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# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #81278]
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On Rakudo 2010.12:

use v6;
sub f($x) {
    multi return($nv) {
        nextwith($nv /2);
    }

    return $x;
}
say f 6

I'd expect that to output 3\n, but instead I get

Null PMC access in clone()
  in 'return' at line 1
  in 'f' at line 7:test.pl
  in main program body at line 9:test.pl

which is sad, because it prevents me from using a "neat" and evil trick.