.phpstorm.meta.php

<?php
namespace PHPSTORM_META {
    registerArgumentsSet("date_units", "millenania", "millennium", "century", "centuries", "decade", "decades", "year", "years", "y", "yr", "yrs", "quarter", "quarters", "month", "months", "mo", "mos", "week", "weeks", "w", "day", "days", "d", "hour", "hours", "h", "minute", "minutes", "m", "second", "seconds", "s", "millisecond", "milliseconds", "milli", "ms", "microsecond", "microseconds", "micro", "µs");
    expectedArguments(\Carbon\Traits\Units::add(), 0, argumentsSet("date_units"));
    expectedArguments(\Carbon\Traits\Units::add(), 1, argumentsSet("date_units"));
    expectedArguments(\Carbon\CarbonInterface::add(), 0, argumentsSet("date_units"));
    expectedArguments(\Carbon\CarbonInterface::add(), 1, argumentsSet("date_units"));

    expectedArguments(\Carbon\CarbonInterface::getTimeFormatByPrecision(), 0, "minute", "second", "m", "millisecond", "µ", "microsecond", "minutes", "seconds", "ms", "milliseconds", "µs", "microseconds");
}