diff --git a/composer.json b/composer.json
index 85c84e5..5a36316 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
     "infection/infection": "~0.15.3",
     "jangregor/phpstan-prophecy": "~0.6.2",
     "phpstan/extension-installer": "^1.0.4",
-    "phpstan/phpstan": "~0.12.19",
+    "phpstan/phpstan": "~0.12.20",
     "phpstan/phpstan-deprecation-rules": "~0.12.2",
     "phpstan/phpstan-phpunit": "~0.12.8",
     "phpstan/phpstan-strict-rules": "~0.12.2",
diff --git a/composer.lock b/composer.lock
index 3062f68..1a67673 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": "926afa8e2192110ebf2eba6fa6a8b13e",
+    "content-hash": "ab9407e9d2789bb93b24b77d975cac42",
     "packages": [],
     "packages-dev": [
         {
@@ -2125,16 +2125,16 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "0.12.19",
+            "version": "0.12.20",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "054f6d76b12ba9a6c13a5a8d5fcdf51219615f4d"
+                "reference": "3d79c7109223aeb2d1157870c5d8875545403917"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/054f6d76b12ba9a6c13a5a8d5fcdf51219615f4d",
-                "reference": "054f6d76b12ba9a6c13a5a8d5fcdf51219615f4d",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/3d79c7109223aeb2d1157870c5d8875545403917",
+                "reference": "3d79c7109223aeb2d1157870c5d8875545403917",
                 "shasum": ""
             },
             "require": {
@@ -2163,7 +2163,7 @@
                 "MIT"
             ],
             "description": "PHPStan - PHP Static Analysis Tool",
-            "time": "2020-04-19T20:35:10+00:00"
+            "time": "2020-05-03T17:12:46+00:00"
         },
         {
             "name": "phpstan/phpstan-deprecation-rules",