Cannot find Pimple\Container.php?

Pimple\Container was used as the keyword for the top use, but this file can't find in my local directory
because In my editor, the Pimple is displayed in red in the use-Pimple\Container section, and is "Undefined namespace is not Referenced"
Nevertheless, the code on the screen does not produce an error and acts as if it were a file.

My guess is that It's an external library but no matter how you look at it, it makes me curious
Is this normal? Or What have I missed?

Hello, where do you using Pimple ? in Owncloud?

Hello, glannes31

this file used path in core\lib\private\AppFramework\Utility\SimpleContainer.php

The contents of the file are as follows.

file namespace OC\AppFramework\Utility;

use ReflectionClass;
use ReflectionException;
use Closure;
use Pimple\Container; <----- this
use OCP\AppFramework\QueryException;
use OCP\IContainer;

.......

Is it a git clone? Did you run make?

yes, it is a git clone.

also i do run make...

did you setup composer.json properly within phpstorm?

thanks DeepDriver1975, i'm solved
I thought of a composer when i saw your upload image
but I thought the dependencies were well-installed because I had already used the "make" command you told me.
but in the end, It was a composer problem.

I installed a composer and used the composer install command, and when a lot of files were downloaded, the red pimple letters naturally turned black.

i don't know the exact cause, but ... It seems difficult to jump in without a general understanding

thanks friend.