[perl #76882] method reference causes Null PMC

[via RT]

# New Ticket Created by  Wenzel Peppmeyer 
# Please include the string:  [perl #76882]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=76882 >


use v6;

class A {
   method b(){ say 'butterfly'; };
};

my $a = A.new();
my $method_ref = $a.^can('b');
$method_ref($a);

sub foo($o, $m){
   $m($o);
};

foo($a, $method_ref);

--

butterfly
Null PMC access in invoke()
   in 'foo' at line 1:method_reference.p6
   in 'foo' at line 11:method_reference.p6
   in main program body at line 15:method_reference.p6