[perl #57422] Assigning to instance hashes,arrays fails

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# New Ticket Created by  Johan Viklund 
# Please include the string:  [perl #57422]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=57422 >


On rakudo (rev. 29869) this fails with message "get_pmc_keyed() not
implemented in class 'Undef'"


class Foo {
    has %.bar is rw;
    method set_bar {
        %.bar<a> = 'baz';
    }
}
my $foo = Foo.new;
$foo.set_bar();


Initializing %.bar to () solves this particular problem, but another
one appears. Shown below


class Foo {
    has %.bar is rw;
    method set_bar {
        %.bar = ();
        %.bar<a> = 'baz';
    }
}
my $foo = Foo.new;
$foo.set_bar();
my %s = $foo.bar; # <- HERE BUG APPEARS


Gives this error: "Odd number of elements found where hash expected"

And the workaround for this is to declare set_bar like this

method set_bar {
    my %bar_temp;
    %bar_temp<a> = 'baz';
    %.bar = %bar_temp;
}


For arrays:

class Foo {
    has @.bar is rw;
    method set_bar {
        @.bar.push('baz');
    }
}

Gives "Method 'push' not found for invocant of class 'Undef'"

Similar workaround as for hash (eg. initialize it first).

-- 
Johan Viklund