public function unknown_positionals( $args ) {
		$positional_repeating = $this->query_spec(
			array(
				'type'      => 'positional',
				'repeating' => true,
			)
		);

		// At least one positional supports as many as possible.
		if ( ! empty( $positional_repeating ) ) {
			return array();
		}

		$positional = $this->query_spec(
			array(
				'type'      => 'positional',
				'repeating' => false,
			)
		);

		return array_slice( $args, count( $positional ) );
	}