Correction: any "non-coderef value is stringified" , even undef is stringified to an empty string. ( It's just tricky to create a sub for an empty symbol. :)

  DB<199> $obj = bless {},"tmp"

  DB<200> $tmp::{''} = sub { say "empty" }

  DB<201> $meth = undef

  DB<202> $obj->$meth
empty

  DB<203>
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I did try undef, but got warnings, so figured it was verboten. I ought to have continued with my experiments.

Here's something fun. Acme::Ref breaks on recent Perls, but it's a one line patch to fix it. (The _deref function needs to take a long argument instead of an int.)

use strict;
use warnings;
use feature 'say';

{
    package Local::Class;
    sub new {
        my ( $class ) = ( shift );
        bless {}, $class;
    }
    sub AUTOLOAD {
        my ( $method ) = ( our $AUTOLOAD =~ /([^:]+)$/ );
        if ( $method =~ /^(ARRAY|HASH|SCALAR|REF)/i ) {
            require Acme::Ref;
            my $real_coderef = $_[0]->can("HANDLE_$1")
                or die "Cannot handle $1 method";
            splice @_, 1, 0, do { local $SIG{__WARN__} = sub {}; Acme:
+:Ref::deref($method); };
            goto $real_coderef;
        }
        return if $method eq 'DESTROY';
        die "Could not load $method via AUTOLOAD";
    }
    sub HANDLE_ARRAY {
        my ( $self, $array, @args ) = ( shift, shift, @_ );
        say for @$array;
    }
    sub HANDLE_HASH {
        say "whatever";
    }
    # etc...
};

my $object = 'Local::Class'->new();

my $array = [ "Hello", "world" ];

$object->$array;

$object->${\ [ "And", "again" ] };
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toby döt ink