package App::Schema::Result::Thing;

__PACKAGE__->might_have( last_event => 'MyApp::Schema::Result::ThingEvent', sub {
   my ($rsrc, $us, $them)= @{$_[0]}{'self_resultsource','self_alias','foreign_alias'};
   my $guard= $rsrc->schema->set_limit_dialect_scope_guard('Top'); # use "SELECT TOP x FROM ..." syntax for subquery
   return {
      "$them.id" => { '=' =>
         $rsrc->schema->resultset('ThingEvent')->alias('thing_max_event')->search({
               'thing_max_event.thing_id' => { -ident => "$us.id" },
            })->last_rs->columns(['thing_max_event.id'])->as_query
      }
   };
});