Fixing a PHP Language Server for my own taste

composer.json

{
    "name": "ciantic/wp",
    "authors": [
        {
            "name": "Ciantic",
            "email": "nothere@example.com"
        }
    ],
    "require": {
        "wp/WordPress": "^4.9",
        "wp-plugins/advanced-custom-fields-pro": "^5.0",
        "wp-plugins/woocommerce": "^5.0"
    }
}

composer.lock

{
    "packages": [
        {
            "name": "wp/WordPress",
            "version": "4.9.4"
        },
        {
            "name": "wp-plugins/advanced-custom-fields-pro",
            "version": "5.6.8"
        },
        {
            "name": "wp-plugins/woocommerce",
            "version": "3.3.3"
        }
    ],
    "packages-dev": []
}

Indexer.php

<?php 

    /**
     * Will read and parse the passed source files in the project and add them to the appropiate indexes
     *
     * @return Promise <void>
     */
    public function index(): Promise
    {
        return coroutine(function () {
            $pattern = Path::makeAbsolute('**/*.php', $this->rootPath);
            $uris = yield $this->filesFinder->find($pattern);

            // CIANTIC Fixes things for good
            if (preg_match("#wp-content[\\\\/]themes#", $this->rootPath)) {
                $this->client->window->logMessage(MessageType::INFO, "My WordPress themes should have stuff from here!");
                $this->composerLock = json_decode(file_get_contents("file:///C:/DepSource/WP/composer.lock"));
                $this->composerJson = json_decode(file_get_contents("file:///C:/DepSource/WP/composer.json"));
                // $this->client->window->logMessage(MessageType::INFO, "test" . var_export($this->composerLock, true) . var_export($this->composerJson, true));
                $uris = array_merge($uris, yield $this->filesFinder->find('C:/DepSource/WP/**/*.php'));
            }

            $count = count($uris);
            $startTime = microtime(true);
            $this->client->window->logMessage(MessageType::INFO, "$count files total");

            /** @var string[] */
            $source = [];
            /** @var string[][] */
            $deps = [];

Also remember to change PHPDocumentLoader.php line $limit = 15... to something greater.

1. Create folder "C:/DepSource/WP"
2. Store the composer.json and composer.lock there
3. Download WordPress to "C:/DepSource/WP/vendor/wp/"
4. Open \felixfbecker.php-intellisense-2.3.4\vendor\felixfbecker\language-server\src\Indexer.php add the changes above

Note This does extra check there: if (preg_match("#wp-content[\\\\/]themes#", $this->rootPath)) { if your themes are not in path wp-content/themes you have to change that.