Set up static code analysis using Psalm

composer.json

@@ -41,7 +41,9 @@
         "fakerphp/faker": "^1.20",
         "mockery/mockery": "^1.5",
         "nunomaduro/collision": "^5.0",
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^9.5",
+        "psalm/plugin-laravel": "1.6.2",
+        "vimeo/psalm": "^4.26"
     },
     "config": {
         "optimize-autoloader": true,

psalm.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="7"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="app"/>
+        <directory name="database/factories"/>
+        <directory name="database/seeders"/>
+        <ignoreFiles>
+            <directory name="vendor"/>
+            <directory name="app/Protobuf"/>
+        </ignoreFiles>
+    </projectFiles>
+    <plugins>
+        <pluginClass class="Psalm\LaravelPlugin\Plugin"/>
+    </plugins>
+</psalm>