Editor can't find class from static method call

The Carbon class exists in vendor/nesbot/carbon/src/Carbon/Carbon.php, and PHPStorm is able to find it from another call in another file, but I'm not seeing why it can't find it in my new model file (under the app folder) even if I delete the preceding `Carbon\` text.

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Abc extends Model
{

    // A B C table in the Data schema

    const CREATED_AT = 'date_time';
    const UPDATED_AT = '';

    public function getCreatedAtAttribute($date)
    {
        return Carbon\Carbon::createFromFormat('Y-m-d H:i:s', $date)->format('Y-m-d');
    }

    public function getUpdatedAtAttribute($date)
    {
        return Carbon\Carbon::createFromFormat('Y-m-d H:i:s', $date)->format('Y-m-d');
    }

    public function stuff()
    {
        return $this->hasMany('App\Stuff', 'ID_papa');
    }

}