why.p6

class Strange {
    has $.env is rw;
    method reset($env) {
        $.env = $env ;
    }

}
class Context {
    has $!env;
    has $.strange = Strange.new;

    method env {
        Proxy.new(
            FETCH => { $!env },
            STORE => -> $, $value {
                # reset response to default
                $!env = $value;
                $!strange.reset($!env);
        },
        );
    }
}

my %env = (1 => 2, 3 => 4);
my $c = Context.new;
sub dispatch($v) {
    $c.env = $v;
}

dispatch(%env);
dispatch(%env);

Cannot assign to a readonly variable or a value
in method reset at Strange.pm line 4
in block at Strange.pm line 18

m: class Strange { has $.env is rw; method reset($env) { $.env = $env } }; my $s = Strange.new; my %env = (1 => 2, 3 => 4); $s.reset(%env); $s.reset(%env)
rakudo-moar 9c8989: OUTPUT«Cannot assign to a readonly variable or a value␤ in method reset at /tmp/plljs3r5Zt line 1␤ in block at /tmp/plljs3r5Zt line 1␤␤»
soo, it's a bug?
pretty sure it is, yes
care to submit it? :)