NQP: Problem with arrays when unshifting/pushing

[bluescreen]

The following snippet is part of actions.pm of the language I'm trying to implement,

method TOP($/,$key) {
    our @?BLOCK;
    our $?BLOCK;
    my $past;

    if $key eq 'open' {
        $?BLOCK := PAST::Block.new( :blocktype('declaration'), :node( $/ ) );
        $?BLOCK.symbol_defaults( :scope('package') );
        say("before unshifting/shifting");
        @?BLOCK.unshift($?BLOCK);
        say(+@?BLOCK);
        @?BLOCK.shift();
        say("after unshifting/shifting" );

it compiles ok but in runtime it get the following error

before unshifting/shifting
0
ResizablePMCArray: Can't shift from an empty array!

If preload @?BLOCK with bogus data it works for example:

@?BLOCK := (1,2);

In this case it doesn't fail. In #parrot plobsing mentioned that could be a problem with autoviv.

[bluescreen]

bug.nqp

[bluescreen]

Step to reproduce:

parrot parrot-2.3.0/compilers/nqp/nqp.pbc bug.nqp 

[coke]

NQP is no longer available (2.3.0 was its last supported release), please use 'parrot-nqp' instead.

In parrot trunk:

$ ./parrot-nqp bug.nqp
1

Regards.