test.nqp

my $UInt32 := nqp::newtype(NQPMu, 'CScalar');
nqp::composetype($UInt32, 'CUInt32');

my $UInt16 := nqp::newtype(NQPMu, 'CScalar');
nqp::composetype($UInt16, 'CUInt16');

#my $Ptr := nqp::newtype(NQPMu, 'CPtr');

my $Collectable := nqp::newtype(NQPMu, 'CStruct');
nqp::composetype($Collectable, [
    $UInt32, 'owner',
    $UInt16, 'flags',
    $UInt16, 'size',
#    $Ptr, 'forwarder',
#    $Ptr, 'sc'
]);

my $ptrtype := nqp::newtype(NQPMu, 'VMPtr');

# unsafe if $obj can move
my $obj := NQPMu;
my $ptr := nqp::box_i(nqp::where($obj), $ptrtype);
my $struct := nqp::ptrcast($ptr, $Collectable, 0);
say(nqp::getattr_i($struct, NQPMu, 'owner'));
say(nqp::getattr_i($struct, NQPMu, 'flags'));
say(nqp::getattr_i($struct, NQPMu, 'size'));