diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
new file mode 100644
index 0000000..d0d22db
--- /dev/null
+++ b/.github/workflows/php.yml
@@ -0,0 +1,46 @@
+name: PHP tests
+on: [push, pull_request]
+jobs:
+  phpstan:
+    permissions:
+      actions: write  # for styfle/cancel-workflow-action to cancel/stop running workflows
+      contents: read  # for actions/checkout to fetch code
+    name: PHP Static Analysis
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1' ]
+      fail-fast: false
+    steps:
+      - name: Cancel Previous Runs
+        uses: styfle/cancel-workflow-action@0.9.0
+        with:
+          access_token: ${{ github.token }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '7.4'
+          extensions: mbstring, intl, gd, xml, dom, json, fileinfo, curl, zip, iconv, simplexml
+
+      - uses: actions/checkout@v2
+
+      - name: Get Composer Cache Directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache Composer Directory
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Composer Install
+        run: |
+          composer install --ansi --prefer-dist --no-interaction --no-progress
+          rm composer.lock
+          composer config platform.php ${{ matrix.php }}
+
+      - name: Run phpstan
+        run: ./vendor/bin/phpstan analyse
diff --git a/composer.json b/composer.json
index c8a99b6..0bf1b1b 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,8 @@
     "ext-SimpleXML": "*"
   },
   "require-dev": {
-    "phpunit/phpunit": "~5.2"
+    "phpunit/phpunit": "~5.2",
+    "phpstan/phpstan": "^1.9"
   },
   "autoload": {
     "psr-4": {
diff --git a/composer.lock b/composer.lock
index c1b1d58..0e25ee5 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "ac1cc801240b769f516f8b686bce361e",
+    "content-hash": "8b8189a56a2c6f495fe4a372a5fce419",
     "packages": [
         {
             "name": "doctrine/inflector",
@@ -1253,6 +1253,65 @@
             },
             "time": "2020-03-05T15:02:03+00:00"
         },
+        {
+            "name": "phpstan/phpstan",
+            "version": "1.9.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "e08de53a5eec983de78a787a88e72518cf8fe43a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/e08de53a5eec983de78a787a88e72518cf8fe43a",
+                "reference": "e08de53a5eec983de78a787a88e72518cf8fe43a",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2|^8.0"
+            },
+            "conflict": {
+                "phpstan/phpstan-shim": "*"
+            },
+            "bin": [
+                "phpstan",
+                "phpstan.phar"
+            ],
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHPStan - PHP Static Analysis Tool",
+            "keywords": [
+                "dev",
+                "static analysis"
+            ],
+            "support": {
+                "issues": "https://github.com/phpstan/phpstan/issues",
+                "source": "https://github.com/phpstan/phpstan/tree/1.9.0"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/ondrejmirtes",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/phpstan",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/phpstan/phpstan",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2022-11-03T07:26:48+00:00"
+        },
         {
             "name": "phpunit/php-code-coverage",
             "version": "4.0.8",
@@ -2299,5 +2358,5 @@
         "ext-simplexml": "*"
     },
     "platform-dev": [],
-    "plugin-api-version": "2.0.0"
+    "plugin-api-version": "2.3.0"
 }
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..5fa5669
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,7 @@
+parameters:
+  paths:
+    - app
+    - src
+  level: 5
+  parallel:
+    maximumNumberOfProcesses: 1
\ No newline at end of file
diff --git a/src/Generator/EntityGenerator.php b/src/Generator/EntityGenerator.php
index 79ca4b6..94e0afa 100644
--- a/src/Generator/EntityGenerator.php
+++ b/src/Generator/EntityGenerator.php
@@ -730,7 +730,7 @@ private function getRelationFromDependencies($relationName, $entityName)
      *
      * @param string $relationName
      *
-     * @return \SimpleXMLElement
+     * @return \SimpleXMLElement|null
      */
     private function getRelationWithMatchingFieldsFromDependencies($relationName)
     {
@@ -795,7 +795,7 @@ private function getRelationWithMatchingFieldsFromDependencies($relationName)
      * @param array $relations
      * @param array $relationFieldValue
      *
-     * @return null
+     * @return \SimpleXMLElement|null
      */
     private function getMatchingRelation(&$relations, $relationFieldValue)
     {
diff --git a/src/Service/XMLGeneratorService.php b/src/Service/XMLGeneratorService.php
index df7a8b3..fd2a313 100644
--- a/src/Service/XMLGeneratorService.php
+++ b/src/Service/XMLGeneratorService.php
@@ -124,7 +124,7 @@ private static function generateXML(
      */
     private static function sortModelWithDependencies(Finder $finder)
     {
-        $dependencies = $storedDependencies = [];
+        $dependencies = $storedDependencies = $parentEntities = [];
 
         foreach ($finder as $file) {
             $pathName = $file->getPathname();