..., 'value' => ... ]`) — composite resolvers like * `Dynamic` do this when the resolver alone knows the exact key/shape and short-circuits the walker. * * Return `null` to signal that the input can't be resolved for this prop type; the walker will * treat it as a skip (or drop the field from the parent object/array). */ abstract class Plain_Resolver_Base { abstract public function resolve( $plain_value ); }