build: Add PHPStan

composer.json

@@ -7,7 +7,8 @@
     },
     "require-dev": {
         "humbug/box": "^4.2",
-        "symfony/var-dumper": "^6.2"
+        "symfony/var-dumper": "^6.2",
+        "phpstan/phpstan": "^1.9"
     },
     "autoload": {
         "psr-4": {

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": "cd4297546e12f0fef941f564d6d9b4c4",
+    "content-hash": "fe9a106d0218c0c62cedc7771a44b321",
     "packages": [
         {
             "name": "psr/container",
@@ -2554,6 +2554,65 @@
             },
             "time": "2022-10-14T12:47:21+00:00"
         },
+        {
+            "name": "phpstan/phpstan",
+            "version": "1.9.14",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "e5fcc96289cf737304286a9b505fbed091f02e58"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/e5fcc96289cf737304286a9b505fbed091f02e58",
+                "reference": "e5fcc96289cf737304286a9b505fbed091f02e58",
+                "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/1.9.14"
+            },
+            "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": "2023-01-19T10:47:09+00:00"
+        },
         {
             "name": "psr/event-dispatcher",
             "version": "1.0.0",

phpstan.neon.dist

@@ -0,0 +1,5 @@
+parameters:
+  level: 8
+  paths:
+    - bin
+    - src