diff --git a/composer.json b/composer.json
index 759a2124a..22afd945b 100644
--- a/composer.json
+++ b/composer.json
@@ -53,6 +53,8 @@
     },
     "require-dev": {
         "codeception/codeception": "^2.4",
+        "phpstan/phpstan": "^0.11",
+        "phpstan/phpstan-strict-rules": "^0.11",
         "phpunit/php-code-coverage": "~6.0",
         "fzaninotto/faker": "^1.8",
         "victorjonsson/markdowndocs": "dev-master"
@@ -80,6 +82,7 @@
     },
     "scripts": {
         "post-create-project-cmd": "bin/grav install",
+        "phpstan": "vendor/bin/phpstan analyse -l 0 -c ./tests/phpstan/phpstan.neon system/src",
         "test": "vendor/bin/codecept run unit",
         "test-windows": "vendor\\bin\\codecept run unit"
     },
diff --git a/composer.lock b/composer.lock
index 49a92af50..863e38203 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": "96bb72327a133062393d3391201403d9",
+    "content-hash": "584da9b89b2ab2de09b0ccc5c4bee34d",
     "packages": [
         {
             "name": "antoligy/dom-string-iterators",
@@ -2787,6 +2787,50 @@
             "description": "Flexible Stub wrapper for PHPUnit's Mock Builder",
             "time": "2019-03-02T15:35:10+00:00"
         },
+        {
+            "name": "composer/xdebug-handler",
+            "version": "1.3.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/composer/xdebug-handler.git",
+                "reference": "d17708133b6c276d6e42ef887a877866b909d892"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/composer/xdebug-handler/zipball/d17708133b6c276d6e42ef887a877866b909d892",
+                "reference": "d17708133b6c276d6e42ef887a877866b909d892",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3.2 || ^7.0",
+                "psr/log": "^1.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.5"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Composer\\XdebugHandler\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "John Stevenson",
+                    "email": "john-stevenson@blueyonder.co.uk"
+                }
+            ],
+            "description": "Restarts a process without xdebug.",
+            "keywords": [
+                "Xdebug",
+                "performance"
+            ],
+            "time": "2019-01-28T20:25:53+00:00"
+        },
         {
             "name": "doctrine/instantiator",
             "version": "1.1.0",
@@ -3067,6 +3111,57 @@
             ],
             "time": "2016-12-20T10:07:11+00:00"
         },
+        {
+            "name": "jean85/pretty-package-versions",
+            "version": "1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Jean85/pretty-package-versions.git",
+                "reference": "75c7effcf3f77501d0e0caa75111aff4daa0dd48"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Jean85/pretty-package-versions/zipball/75c7effcf3f77501d0e0caa75111aff4daa0dd48",
+                "reference": "75c7effcf3f77501d0e0caa75111aff4daa0dd48",
+                "shasum": ""
+            },
+            "require": {
+                "ocramius/package-versions": "^1.2.0",
+                "php": "^7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Jean85\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Alessandro Lai",
+                    "email": "alessandro.lai85@gmail.com"
+                }
+            ],
+            "description": "A wrapper for ocramius/package-versions to get pretty versions strings",
+            "keywords": [
+                "composer",
+                "package",
+                "release",
+                "versions"
+            ],
+            "time": "2018-06-13T13:22:40+00:00"
+        },
         {
             "name": "myclabs/deep-copy",
             "version": "1.8.1",
@@ -3115,6 +3210,584 @@
             ],
             "time": "2018-06-11T23:09:50+00:00"
         },
+        {
+            "name": "nette/bootstrap",
+            "version": "v2.4.6",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/bootstrap.git",
+                "reference": "268816e3f1bb7426c3a4ceec2bd38a036b532543"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/bootstrap/zipball/268816e3f1bb7426c3a4ceec2bd38a036b532543",
+                "reference": "268816e3f1bb7426c3a4ceec2bd38a036b532543",
+                "shasum": ""
+            },
+            "require": {
+                "nette/di": "~2.4.7",
+                "nette/utils": "~2.4",
+                "php": ">=5.6.0"
+            },
+            "conflict": {
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "latte/latte": "~2.2",
+                "nette/application": "~2.3",
+                "nette/caching": "~2.3",
+                "nette/database": "~2.3",
+                "nette/forms": "~2.3",
+                "nette/http": "~2.4.0",
+                "nette/mail": "~2.3",
+                "nette/robot-loader": "^2.4.2 || ^3.0",
+                "nette/safe-stream": "~2.2",
+                "nette/security": "~2.3",
+                "nette/tester": "~2.0",
+                "tracy/tracy": "^2.4.1"
+            },
+            "suggest": {
+                "nette/robot-loader": "to use Configurator::createRobotLoader()",
+                "tracy/tracy": "to use Configurator::enableTracy()"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.4-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🅱 Nette Bootstrap: the simple way to configure and bootstrap your Nette application.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "bootstrapping",
+                "configurator",
+                "nette"
+            ],
+            "time": "2018-05-17T12:52:20+00:00"
+        },
+        {
+            "name": "nette/di",
+            "version": "v2.4.15",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/di.git",
+                "reference": "d0561b8f77e8ef2ed6d83328860e16c81a5a8649"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/di/zipball/d0561b8f77e8ef2ed6d83328860e16c81a5a8649",
+                "reference": "d0561b8f77e8ef2ed6d83328860e16c81a5a8649",
+                "shasum": ""
+            },
+            "require": {
+                "ext-tokenizer": "*",
+                "nette/neon": "^2.3.3 || ~3.0.0",
+                "nette/php-generator": "^2.6.1 || ^3.0.0",
+                "nette/utils": "^2.5.0 || ~3.0.0",
+                "php": ">=5.6.0"
+            },
+            "conflict": {
+                "nette/bootstrap": "<2.4",
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "nette/tester": "^2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.4-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "💎 Nette Dependency Injection Container: Flexible, compiled and full-featured DIC with perfectly usable autowiring and support for all new PHP 7.1 features.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "compiled",
+                "di",
+                "dic",
+                "factory",
+                "ioc",
+                "nette",
+                "static"
+            ],
+            "time": "2019-01-30T13:26:05+00:00"
+        },
+        {
+            "name": "nette/finder",
+            "version": "v2.5.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/finder.git",
+                "reference": "6be1b83ea68ac558aff189d640abe242e0306fe2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/finder/zipball/6be1b83ea68ac558aff189d640abe242e0306fe2",
+                "reference": "6be1b83ea68ac558aff189d640abe242e0306fe2",
+                "shasum": ""
+            },
+            "require": {
+                "nette/utils": "^2.4 || ~3.0.0",
+                "php": ">=7.1"
+            },
+            "conflict": {
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "nette/tester": "^2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.5-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🔍 Nette Finder: find files and directories with an intuitive API.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "filesystem",
+                "glob",
+                "iterator",
+                "nette"
+            ],
+            "time": "2019-02-28T18:13:25+00:00"
+        },
+        {
+            "name": "nette/neon",
+            "version": "v3.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/neon.git",
+                "reference": "cbff32059cbdd8720deccf9e9eace6ee516f02eb"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/neon/zipball/cbff32059cbdd8720deccf9e9eace6ee516f02eb",
+                "reference": "cbff32059cbdd8720deccf9e9eace6ee516f02eb",
+                "shasum": ""
+            },
+            "require": {
+                "ext-iconv": "*",
+                "ext-json": "*",
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "nette/tester": "^2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🍸 Nette NEON: encodes and decodes NEON file format.",
+            "homepage": "http://ne-on.org",
+            "keywords": [
+                "export",
+                "import",
+                "neon",
+                "nette",
+                "yaml"
+            ],
+            "time": "2019-02-05T21:30:40+00:00"
+        },
+        {
+            "name": "nette/php-generator",
+            "version": "v3.2.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/php-generator.git",
+                "reference": "9de4e093a130f7a1bd175198799ebc0efbac6924"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/php-generator/zipball/9de4e093a130f7a1bd175198799ebc0efbac6924",
+                "reference": "9de4e093a130f7a1bd175198799ebc0efbac6924",
+                "shasum": ""
+            },
+            "require": {
+                "nette/utils": "^2.4.2 || ~3.0.0",
+                "php": ">=7.1"
+            },
+            "conflict": {
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "nette/tester": "^2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.2-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🐘 Nette PHP Generator: generates neat PHP code for you. Supports new PHP 7.3 features.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "code",
+                "nette",
+                "php",
+                "scaffolding"
+            ],
+            "time": "2018-11-27T19:00:14+00:00"
+        },
+        {
+            "name": "nette/robot-loader",
+            "version": "v3.1.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/robot-loader.git",
+                "reference": "3e8d75d6d976e191bdf46752ca40a286671219d2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/robot-loader/zipball/3e8d75d6d976e191bdf46752ca40a286671219d2",
+                "reference": "3e8d75d6d976e191bdf46752ca40a286671219d2",
+                "shasum": ""
+            },
+            "require": {
+                "ext-tokenizer": "*",
+                "nette/finder": "^2.3 || ^3.0",
+                "nette/utils": "^2.4 || ^3.0",
+                "php": ">=5.6.0"
+            },
+            "conflict": {
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "nette/tester": "^2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.1-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🍀 Nette RobotLoader: high performance and comfortable autoloader that will search and autoload classes within your application.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "autoload",
+                "class",
+                "interface",
+                "nette",
+                "trait"
+            ],
+            "time": "2019-03-01T20:23:02+00:00"
+        },
+        {
+            "name": "nette/utils",
+            "version": "v2.5.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/utils.git",
+                "reference": "17b9f76f2abd0c943adfb556e56f2165460b15ce"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/utils/zipball/17b9f76f2abd0c943adfb556e56f2165460b15ce",
+                "reference": "17b9f76f2abd0c943adfb556e56f2165460b15ce",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6.0"
+            },
+            "conflict": {
+                "nette/nette": "<2.2"
+            },
+            "require-dev": {
+                "nette/tester": "~2.0",
+                "tracy/tracy": "^2.3"
+            },
+            "suggest": {
+                "ext-gd": "to use Image",
+                "ext-iconv": "to use Strings::webalize() and toAscii()",
+                "ext-intl": "for script transliteration in Strings::webalize() and toAscii()",
+                "ext-json": "to use Nette\\Utils\\Json",
+                "ext-mbstring": "to use Strings::lower() etc...",
+                "ext-xml": "to use Strings::length() etc. when mbstring is not available"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.5-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ],
+                "files": [
+                    "src/loader.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0",
+                "GPL-3.0"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🛠 Nette Utils: lightweight utilities for string & array manipulation, image handling, safe JSON encoding/decoding, validation, slug or strong password generating etc.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "array",
+                "core",
+                "datetime",
+                "images",
+                "json",
+                "nette",
+                "paginator",
+                "password",
+                "slugify",
+                "string",
+                "unicode",
+                "utf-8",
+                "utility",
+                "validation"
+            ],
+            "time": "2018-09-18T10:22:16+00:00"
+        },
+        {
+            "name": "nikic/php-parser",
+            "version": "v4.2.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nikic/PHP-Parser.git",
+                "reference": "5221f49a608808c1e4d436df32884cbc1b821ac0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/5221f49a608808c1e4d436df32884cbc1b821ac0",
+                "reference": "5221f49a608808c1e4d436df32884cbc1b821ac0",
+                "shasum": ""
+            },
+            "require": {
+                "ext-tokenizer": "*",
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.5 || ^7.0"
+            },
+            "bin": [
+                "bin/php-parse"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "4.2-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PhpParser\\": "lib/PhpParser"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Nikita Popov"
+                }
+            ],
+            "description": "A PHP parser written in PHP",
+            "keywords": [
+                "parser",
+                "php"
+            ],
+            "time": "2019-02-16T20:54:15+00:00"
+        },
+        {
+            "name": "ocramius/package-versions",
+            "version": "1.4.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Ocramius/PackageVersions.git",
+                "reference": "a4d4b60d0e60da2487bd21a2c6ac089f85570dbb"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Ocramius/PackageVersions/zipball/a4d4b60d0e60da2487bd21a2c6ac089f85570dbb",
+                "reference": "a4d4b60d0e60da2487bd21a2c6ac089f85570dbb",
+                "shasum": ""
+            },
+            "require": {
+                "composer-plugin-api": "^1.0.0",
+                "php": "^7.1.0"
+            },
+            "require-dev": {
+                "composer/composer": "^1.6.3",
+                "doctrine/coding-standard": "^5.0.1",
+                "ext-zip": "*",
+                "infection/infection": "^0.7.1",
+                "phpunit/phpunit": "^7.0.0"
+            },
+            "type": "composer-plugin",
+            "extra": {
+                "class": "PackageVersions\\Installer",
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PackageVersions\\": "src/PackageVersions"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Marco Pivetta",
+                    "email": "ocramius@gmail.com"
+                }
+            ],
+            "description": "Composer plugin that provides efficient querying for installed package versions (no runtime IO)",
+            "time": "2019-02-21T12:16:21+00:00"
+        },
         {
             "name": "phar-io/manifest",
             "version": "1.0.3",
@@ -3432,6 +4105,171 @@
             ],
             "time": "2018-08-05T17:53:17+00:00"
         },
+        {
+            "name": "phpstan/phpdoc-parser",
+            "version": "0.3.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpdoc-parser.git",
+                "reference": "2cc49f47c69b023eaf05b48e6529389893b13d74"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpdoc-parser/zipball/2cc49f47c69b023eaf05b48e6529389893b13d74",
+                "reference": "2cc49f47c69b023eaf05b48e6529389893b13d74",
+                "shasum": ""
+            },
+            "require": {
+                "php": "~7.1"
+            },
+            "require-dev": {
+                "consistence/coding-standard": "^2.0.0",
+                "jakub-onderka/php-parallel-lint": "^0.9.2",
+                "phing/phing": "^2.16.0",
+                "phpstan/phpstan": "^0.10",
+                "phpunit/phpunit": "^6.3",
+                "slevomat/coding-standard": "^3.3.0",
+                "symfony/process": "^3.4 || ^4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "0.3-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PHPStan\\PhpDocParser\\": [
+                        "src/"
+                    ]
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHPDoc parser with support for nullable, intersection and generic types",
+            "time": "2019-01-14T12:26:23+00:00"
+        },
+        {
+            "name": "phpstan/phpstan",
+            "version": "0.11.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "8e185a74004920419ee97bf9dc62e6a175e8dca5"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/8e185a74004920419ee97bf9dc62e6a175e8dca5",
+                "reference": "8e185a74004920419ee97bf9dc62e6a175e8dca5",
+                "shasum": ""
+            },
+            "require": {
+                "composer/xdebug-handler": "^1.3.0",
+                "jean85/pretty-package-versions": "^1.0.3",
+                "nette/bootstrap": "^2.4 || ^3.0",
+                "nette/di": "^2.4.7 || ^3.0",
+                "nette/robot-loader": "^3.0.1",
+                "nette/utils": "^2.4.5 || ^3.0",
+                "nikic/php-parser": "^4.0.2",
+                "php": "~7.1",
+                "phpstan/phpdoc-parser": "^0.3",
+                "symfony/console": "~3.2 || ~4.0",
+                "symfony/finder": "~3.2 || ~4.0"
+            },
+            "conflict": {
+                "symfony/console": "3.4.16 || 4.1.5"
+            },
+            "require-dev": {
+                "brianium/paratest": "^2.0",
+                "consistence/coding-standard": "^3.5",
+                "dealerdirect/phpcodesniffer-composer-installer": "^0.4.4",
+                "ext-intl": "*",
+                "ext-mysqli": "*",
+                "ext-soap": "*",
+                "ext-zip": "*",
+                "jakub-onderka/php-parallel-lint": "^1.0",
+                "localheinz/composer-normalize": "^1.1.0",
+                "phing/phing": "^2.16.0",
+                "phpstan/phpstan-deprecation-rules": "^0.11",
+                "phpstan/phpstan-php-parser": "^0.11",
+                "phpstan/phpstan-phpunit": "^0.11",
+                "phpstan/phpstan-strict-rules": "^0.11",
+                "phpunit/phpunit": "^7.0",
+                "slevomat/coding-standard": "^4.7.2",
+                "squizlabs/php_codesniffer": "^3.3.2"
+            },
+            "bin": [
+                "bin/phpstan"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "0.11-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PHPStan\\": [
+                        "src/",
+                        "build/PHPStan"
+                    ]
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHPStan - PHP Static Analysis Tool",
+            "time": "2019-02-12T14:54:38+00:00"
+        },
+        {
+            "name": "phpstan/phpstan-strict-rules",
+            "version": "0.11",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan-strict-rules.git",
+                "reference": "747a742b26a35ef4e4ebef5ec4490ad74eebcbc0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan-strict-rules/zipball/747a742b26a35ef4e4ebef5ec4490ad74eebcbc0",
+                "reference": "747a742b26a35ef4e4ebef5ec4490ad74eebcbc0",
+                "shasum": ""
+            },
+            "require": {
+                "nikic/php-parser": "^4.0",
+                "php": "~7.1",
+                "phpstan/phpstan": "^0.11"
+            },
+            "require-dev": {
+                "consistence/coding-standard": "^3.0.1",
+                "dealerdirect/phpcodesniffer-composer-installer": "^0.4.4",
+                "jakub-onderka/php-parallel-lint": "^1.0",
+                "phing/phing": "^2.16.0",
+                "phpstan/phpstan-phpunit": "^0.11",
+                "phpunit/phpunit": "^7.0",
+                "slevomat/coding-standard": "^4.5.2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "0.11-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "PHPStan\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Extra strict and opinionated rules for PHPStan",
+            "time": "2019-01-14T09:56:55+00:00"
+        },
         {
             "name": "phpunit/php-code-coverage",
             "version": "6.1.4",
diff --git a/system/src/Grav/Common/Config/Languages.php b/system/src/Grav/Common/Config/Languages.php
index 815e67fd5..9c76dc562 100644
--- a/system/src/Grav/Common/Config/Languages.php
+++ b/system/src/Grav/Common/Config/Languages.php
@@ -14,6 +14,22 @@ use Grav\Common\Utils;
 
 class Languages extends Data
 {
+    /**
+     * @var string|null
+     */
+    protected $checksum;
+
+    /**
+     * @var string|null
+     */
+    protected $modified;
+
+    /**
+     * @var string|null
+     */
+    protected $timestamp;
+
+
     public function checksum($checksum = null)
     {
         if ($checksum !== null) {
diff --git a/system/src/Grav/Common/GPM/Common/CachedCollection.php b/system/src/Grav/Common/GPM/Common/CachedCollection.php
index b3450127b..7c769752e 100644
--- a/system/src/Grav/Common/GPM/Common/CachedCollection.php
+++ b/system/src/Grav/Common/GPM/Common/CachedCollection.php
@@ -17,6 +17,7 @@ class CachedCollection extends Iterator {
 
     public function __construct($items)
     {
+        parent::__construct();
         // local cache to speed things up
         if (!isset(self::$cache[get_called_class() . __METHOD__])) {
             self::$cache[get_called_class() . __METHOD__] = $items;
diff --git a/system/src/Grav/Common/GPM/Common/Package.php b/system/src/Grav/Common/GPM/Common/Package.php
index 6fd808b88..d205f1ee1 100644
--- a/system/src/Grav/Common/GPM/Common/Package.php
+++ b/system/src/Grav/Common/GPM/Common/Package.php
@@ -13,6 +13,9 @@ use Grav\Common\Data\Data;
 
 class Package {
 
+    /**
+     * @var Data
+     */
     protected $data;
 
     public function __construct(Data $package, $type = null)
@@ -24,6 +27,9 @@ class Package {
         }
     }
 
+    /**
+     * @return Data
+     */
     public function getData()
     {
         return $this->data;
@@ -54,6 +60,9 @@ class Package {
         return $this->data->toJson();
     }
 
+    /**
+     * @return array
+     */
     public function toArray()
     {
         return $this->data->toArray();
diff --git a/system/src/Grav/Common/GPM/GPM.php b/system/src/Grav/Common/GPM/GPM.php
index 9d6496ec7..28813d471 100644
--- a/system/src/Grav/Common/GPM/GPM.php
+++ b/system/src/Grav/Common/GPM/GPM.php
@@ -54,6 +54,7 @@ class GPM extends Iterator
      */
     public function __construct($refresh = false, $callback = null)
     {
+        parent::__construct();
         $this->installed = new Local\Packages();
         try {
             $this->repository = new Remote\Packages($refresh, $callback);
diff --git a/system/src/Grav/Common/GPM/Local/AbstractPackageCollection.php b/system/src/Grav/Common/GPM/Local/AbstractPackageCollection.php
index 68b3df651..9acc08385 100644
--- a/system/src/Grav/Common/GPM/Local/AbstractPackageCollection.php
+++ b/system/src/Grav/Common/GPM/Local/AbstractPackageCollection.php
@@ -15,6 +15,7 @@ abstract class AbstractPackageCollection extends BaseCollection
 {
     public function __construct($items)
     {
+        parent::__construct();
         foreach ($items as $name => $data) {
             $data->set('slug', $name);
             $this->items[$name] = new Package($data, $this->type);
diff --git a/system/src/Grav/Common/GPM/Remote/AbstractPackageCollection.php b/system/src/Grav/Common/GPM/Remote/AbstractPackageCollection.php
index 629e0005e..f72dd2673 100644
--- a/system/src/Grav/Common/GPM/Remote/AbstractPackageCollection.php
+++ b/system/src/Grav/Common/GPM/Remote/AbstractPackageCollection.php
@@ -41,6 +41,7 @@ class AbstractPackageCollection extends BaseCollection
      */
     public function __construct($repository = null, $refresh = false, $callback = null)
     {
+        parent::__construct();
         if ($repository === null) {
             throw new \RuntimeException("A repository is required to indicate the origin of the remote collection");
         }
diff --git a/system/src/Grav/Common/GPM/Response.php b/system/src/Grav/Common/GPM/Response.php
index 966771dba..0296301d8 100644
--- a/system/src/Grav/Common/GPM/Response.php
+++ b/system/src/Grav/Common/GPM/Response.php
@@ -303,7 +303,7 @@ class Response
         if ($content === false) {
             $code = null;
             if (isset($http_response_header)) {
-                $code = explode(' ', $http_response_header[0])[1];
+                $code = explode(' ', $http_response_header[0] ?? '')[1] ?? null;
             }
 
             switch ($code) {
diff --git a/system/src/Grav/Common/Language/Language.php b/system/src/Grav/Common/Language/Language.php
index 40ab6355a..bcd04f351 100644
--- a/system/src/Grav/Common/Language/Language.php
+++ b/system/src/Grav/Common/Language/Language.php
@@ -17,6 +17,9 @@ class Language
 {
     protected $grav;
     protected $enabled = true;
+    /**
+     * @var array
+     */
     protected $languages = [];
     protected $page_extensions = [];
     protected $fallback_languages = [];
@@ -78,7 +81,7 @@ class Language
     /**
      * Sets the current supported languages manually
      *
-     * @param $langs
+     * @param array $langs
      */
     public function setLanguages($langs)
     {
@@ -488,6 +491,8 @@ class Language
                 return $accept_langs;
             }
 
+            $langs = [];
+
             foreach (explode(',', $accept_langs) as $k => $pref) {
                 // split $pref again by ';q='
                 // and decorate the language entries by inverted position
diff --git a/system/src/Grav/Common/Processors/ProcessorBase.php b/system/src/Grav/Common/Processors/ProcessorBase.php
index 574ad6f92..5ce7bfd29 100644
--- a/system/src/Grav/Common/Processors/ProcessorBase.php
+++ b/system/src/Grav/Common/Processors/ProcessorBase.php
@@ -17,6 +17,9 @@ abstract class ProcessorBase implements ProcessorInterface
     /** @var Grav */
     protected $container;
 
+    public $id = 'processorbase';
+    public $title = 'ProcessorBase';
+
     public function __construct(Grav $container)
     {
         $this->container = $container;
diff --git a/system/src/Grav/Common/Twig/TwigExtension.php b/system/src/Grav/Common/Twig/TwigExtension.php
index 0462e2ca3..4b498f986 100644
--- a/system/src/Grav/Common/Twig/TwigExtension.php
+++ b/system/src/Grav/Common/Twig/TwigExtension.php
@@ -134,7 +134,7 @@ class TwigExtension extends \Twig_Extension implements \Twig_Extension_GlobalsIn
             new \Twig_SimpleFunction('array_key_exists', 'array_key_exists'),
             new \Twig_SimpleFunction('array_unique', 'array_unique'),
             new \Twig_SimpleFunction('array_intersect', [$this, 'arrayIntersectFunc']),
-            new \Twig_simpleFunction('authorize', [$this, 'authorize']),
+            new \Twig_SimpleFunction('authorize', [$this, 'authorize']),
             new \Twig_SimpleFunction('debug', [$this, 'dump'], ['needs_context' => true, 'needs_environment' => true]),
             new \Twig_SimpleFunction('dump', [$this, 'dump'], ['needs_context' => true, 'needs_environment' => true]),
             new \Twig_SimpleFunction('vardump', [$this, 'vardumpFunc']),
@@ -145,7 +145,7 @@ class TwigExtension extends \Twig_Extension implements \Twig_Extension_GlobalsIn
             new \Twig_SimpleFunction('gist', [$this, 'gistFunc']),
             new \Twig_SimpleFunction('nonce_field', [$this, 'nonceFieldFunc']),
             new \Twig_SimpleFunction('pathinfo', 'pathinfo'),
-            new \Twig_simpleFunction('random_string', [$this, 'randomStringFunc']),
+            new \Twig_SimpleFunction('random_string', [$this, 'randomStringFunc']),
             new \Twig_SimpleFunction('repeat', [$this, 'repeatFunc']),
             new \Twig_SimpleFunction('regex_replace', [$this, 'regexReplace']),
             new \Twig_SimpleFunction('regex_filter', [$this, 'regexFilter']),
@@ -170,13 +170,13 @@ class TwigExtension extends \Twig_Extension implements \Twig_Extension_GlobalsIn
 
 
             // Translations
-            new \Twig_simpleFunction('t', [$this, 'translate'], ['needs_environment' => true]),
-            new \Twig_simpleFunction('tl', [$this, 'translateLanguage']),
-            new \Twig_simpleFunction('ta', [$this, 'translateArray']),
+            new \Twig_SimpleFunction('t', [$this, 'translate'], ['needs_environment' => true]),
+            new \Twig_SimpleFunction('tl', [$this, 'translateLanguage']),
+            new \Twig_SimpleFunction('ta', [$this, 'translateArray']),
 
             // Object Types
-            new \Twig_simpleFunction('get_type', [$this, 'getTypeFunc']),
-            new \Twig_simpleFunction('of_type', [$this, 'ofTypeFunc'])
+            new \Twig_SimpleFunction('get_type', [$this, 'getTypeFunc']),
+            new \Twig_SimpleFunction('of_type', [$this, 'ofTypeFunc'])
         ];
     }
 
diff --git a/system/src/Grav/Common/User/FlexUser/User.php b/system/src/Grav/Common/User/FlexUser/User.php
index 95f833f90..4819c486f 100644
--- a/system/src/Grav/Common/User/FlexUser/User.php
+++ b/system/src/Grav/Common/User/FlexUser/User.php
@@ -57,6 +57,11 @@ class User extends FlexObject implements UserInterface, MediaManipulationInterfa
 
     protected $_uploads_original;
 
+    /**
+     * @var FileInterface|null
+     */
+    protected $storage;
+
     /**
      * @return array
      */
@@ -399,7 +404,7 @@ class User extends FlexObject implements UserInterface, MediaManipulationInterfa
      */
     public function file(FileInterface $storage = null)
     {
-        if ($storage) {
+        if (null !== $storage) {
             $this->storage = $storage;
         }
 
diff --git a/system/src/Grav/Framework/Cache/Adapter/FileCache.php b/system/src/Grav/Framework/Cache/Adapter/FileCache.php
index 89f7d6e6e..27b96391a 100644
--- a/system/src/Grav/Framework/Cache/Adapter/FileCache.php
+++ b/system/src/Grav/Framework/Cache/Adapter/FileCache.php
@@ -139,7 +139,7 @@ class FileCache extends AbstractCache
      * @param string $directory
      * @throws \Psr\SimpleCache\InvalidArgumentException
      */
-    private function init($namespace, $directory)
+    protected function init($namespace, $directory)
     {
         if (!isset($directory[0])) {
             $directory = sys_get_temp_dir() . '/grav-cache';
diff --git a/system/src/Grav/Framework/Flex/FlexIndex.php b/system/src/Grav/Framework/Flex/FlexIndex.php
index 28dc5d723..c31930ad7 100644
--- a/system/src/Grav/Framework/Flex/FlexIndex.php
+++ b/system/src/Grav/Framework/Flex/FlexIndex.php
@@ -23,7 +23,7 @@ use Grav\Framework\Object\Interfaces\ObjectCollectionInterface;
 use Grav\Framework\Object\Interfaces\ObjectInterface;
 use Grav\Framework\Object\ObjectIndex;
 use Monolog\Logger;
-use PSR\SimpleCache\InvalidArgumentException;
+use Psr\SimpleCache\InvalidArgumentException;
 
 class FlexIndex extends ObjectIndex implements FlexCollectionInterface, FlexIndexInterface
 {
diff --git a/system/src/Grav/Framework/Form/FormFlash.php b/system/src/Grav/Framework/Form/FormFlash.php
index 15e7ddd51..690bcec66 100644
--- a/system/src/Grav/Framework/Form/FormFlash.php
+++ b/system/src/Grav/Framework/Form/FormFlash.php
@@ -32,6 +32,8 @@ class FormFlash implements \JsonSerializable
     protected $files;
     /** @var array */
     protected $uploadedFiles;
+    /** @var array<string, mixed> */
+    protected $uploadObjects;
     /** @var bool */
     protected $exists;
 
diff --git a/tests/phpstan/phpstan-bootstrap.php b/tests/phpstan/phpstan-bootstrap.php
new file mode 100644
index 000000000..656ca5fd2
--- /dev/null
+++ b/tests/phpstan/phpstan-bootstrap.php
@@ -0,0 +1,6 @@
+<?php declare(strict_types=1);
+/**
+ *To help phpstan dealing with LogicException in Common\User\User.php
+ */
+
+define('GRAV_USER_INSTANCE', 'FLEX');
diff --git a/tests/phpstan/phpstan.neon b/tests/phpstan/phpstan.neon
new file mode 100644
index 000000000..0dd4fcc1a
--- /dev/null
+++ b/tests/phpstan/phpstan.neon
@@ -0,0 +1,54 @@
+includes:
+	#- vendor/phpstan/phpstan-strict-rules/rules.neon
+parameters:
+    fileExtensions:
+        - php
+        - dist
+    bootstrap: tests/phpstan/phpstan-bootstrap.php
+    excludes_analyse:
+        - system/src/Grav/Common/Errors/Resources/layout.html.php
+    reportUnmatchedIgnoredErrors: true
+    ignoreErrors:
+
+        # Errors that needs some more thinking (design...)
+
+        # Needed: full coverage (probably with admin plugin...) then redesign constructor
+        -
+            message: '#Grav\\Common\\GPM\\Remote\\GravCore::__construct\(\) does not call parent constructor from Grav\\Common\\GPM\\Remote\\AbstractPackageCollection#'
+            path: system/src/Grav/Common/GPM/Remote/GravCore.php
+
+        # Needed: psr-17 (http-factories) support (through decorator or further investigations)
+        -
+            message: '#Call to an undefined static method Grav\\Framework\\Psr7\\Stream::create\(\).#'
+            path: system/src/Grav/Framework/Form/FormFlashFile.php
+
+
+        # Those errors are about plugins (need to find a better solution)
+
+        -
+            message: '#Call to static method sendEmail\(\) on an unknown class Grav\\Plugin\\Email\\Utils.#'
+            path: system/src/Grav/Common/Scheduler/Job.php
+
+        # Can be ignored, after fopen there's always an $http_response_header locally available
+
+        -
+            message: '#Variable \$http_response_header in isset\(\) always exists and is not nullable.#'
+            path: system/src/Grav/Common/GPM/Response.php
+
+
+        # Those errors can be ignored (they depends on installed extensions)
+
+        -
+            message: '#Instantiated class Memcache not found#'
+            path: system/src/Grav/Common/Cache.php
+        -
+            message: '#Instantiated class Redis not found#'
+            path: system/src/Grav/Common/Cache.php
+        -
+            message: '#Instantiated class RedisException not found#'
+            path: system/src/Grav/Common/Cache.php
+
+
+
+
+
diff --git a/tests/unit/Grav/Common/InflectorTest.php b/tests/unit/Grav/Common/InflectorTest.php
index 9caa3e810..9fad48964 100644
--- a/tests/unit/Grav/Common/InflectorTest.php
+++ b/tests/unit/Grav/Common/InflectorTest.php
@@ -13,7 +13,7 @@ class InflectorTest extends \Codeception\TestCase\Test
     /** @var Grav $grav */
     protected $grav;
 
-    /** @var Uri $uri */
+    /** @var Inflector $uri */
     protected $inflector;
 
     protected function _before()