Add php stan with run and apply fixes to conform to the requirements

Author: vukanac

.gitignore

@@ -10,3 +10,4 @@ composer.phar
 /build/
 # Ignore local infection overrides.
 infection.json
+.phpunit.result.cache

.travis.yml

@@ -22,6 +22,7 @@ script:
   - vendor/bin/phpcs --standard=PSR2 src
   - vendor/bin/phpcpd src tests
   - vendor/bin/phpunit --coverage-clover=coverage.xml
+  - vendor/bin/phpstan analyse src tests
   - ./infection.phar --min-msi=48 --threads=4
 
 # public repo on Travis CI (without token)

README.md

@@ -45,6 +45,13 @@ They will help you to write code with consistent style (quotation, indentation,
 * phpcpd
 
 
+### PHPstan ##
+
+The PHP Static Analysis tool.
+
+    $ vendor/bin/phpstan analyse src tests
+
+
 ### The best use
 
 Install plugins to Sublime Text 3:

composer.json

@@ -12,15 +12,23 @@
     "require": {
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.4",
+        "phpstan/extension-installer": "^1.0",
+        "phpstan/phpstan": "^0.11.16",
+        "phpstan/phpstan-phpunit": "^0.11.2",
+        "phpunit/phpunit": "^8.4",
         "sebastian/phpcpd": "^4.1",
-        "squizlabs/php_codesniffer": "^3.3"
+        "squizlabs/php_codesniffer": "^3.5"
     },
     "autoload": {
         "psr-4": {
             "App\\": "src/"
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "Tests\\": "tests/"
+        }
+    },
     "scripts-descriptions": {
         "phpcs": "Checks that the code conforms to coding standard",
         "phpcbf": "Checks and FIX the code to coding standard",
@@ -32,11 +40,13 @@
             "@composer validate --no-check-all --strict",
             "@phpcs",
             "@phpcpd",
+            "@phpstan",
             "@test"
         ],
         "phpcs": "phpcs --standard=PSR2 src",
         "phpcbf": "phpcbf --standard=PSR2 src tests",
         "phpcpd": "phpcpd src tests",
+        "phpstan": "phpstan analyse --level=max src tests",
         "test": "phpunit"
     },
     "minimum-stability": "stable",
@@ -45,7 +55,7 @@
         "process-timeout": 0,
         "sort-packages": true,
         "platform": {
-            "php": "7.2"
+            "php": "7.3"
         }
     }
 }