test.pl

#!perl

use v5.38;

package Test::Foo;
use v5.38;
use experimental 'class';

sub get_bar (@args) {
    Test::Foo::Bar->new( @args )
}

class Test::Foo::Bar {
    field $bar :param = "BAR";

    method bar { $bar }
}

package main;

my $foo = Test::Foo::Bar->new;
warn $foo->bar;

__END__

Subroutine attributes must come before the signature at t/test.pl line 14.