Added fixes for phpstan tests

Author: jaxwilko

phpstan.neon

@@ -1,7 +1,5 @@
 parameters:
+    reportUnmatchedIgnoredErrors: false
     level: 5
     paths:
         - src
-    ignoreErrors:
-        - message: '#Access to an undefined property.*?\$expr#'
-          path: src/ArrayFile.php

src/ArrayFile.php

@@ -155,6 +155,7 @@ public function set($key, $value = null)
             if ($target->value->name->parts[0] !== 'env' || !isset($target->value->args[0])) {
                 return $this;
             }
+            /* @phpstan-ignore-next-line */
             if (isset($target->value->args[0]) && !isset($target->value->args[1])) {
                 $target->value->args[1] = new Arg($this->makeAstNode($valueType, $value));
             }

src/DataFile.php

@@ -9,7 +9,7 @@ abstract class DataFile implements DataFileInterface
     /**
      * Abstract syntax tree
      *
-     * @var \PhpParser\Node\Stmt[]|array<int, array>
+     * @var mixed
      */
     protected $ast = [];