[perl #126787] Call to method that does not exist in a Promise

[via RT]

# New Ticket Created by  Juerd Waalboer 
# Please include the string:  [perl #126787]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=126787 >


    use v6;

    my $foo;

    my $promise = Promise.new;
    $promise.then: {
        note 41;
        $foo.does-not-exist;  # hangs? thread dies? no error message!
        note 42;  # never reached!
    };

    $promise.keep;  # no difference with break

    sleep 60;