diff --git a/composer.json b/composer.json
index 2bb3d2ea..60e89c5c 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
         "ast"
     ],
     "require": {
-        "rector/rector": "~0.19.0",
+        "rector/rector": "^1.0",
         "webflo/drupal-finder": "^1.2"
     },
     "license": "MIT",
diff --git a/src/Drupal9/Rector/ValueObject/AssertLegacyTraitConfiguration.php b/src/Drupal9/Rector/ValueObject/AssertLegacyTraitConfiguration.php
index e57041cf..f321fb32 100644
--- a/src/Drupal9/Rector/ValueObject/AssertLegacyTraitConfiguration.php
+++ b/src/Drupal9/Rector/ValueObject/AssertLegacyTraitConfiguration.php
@@ -22,7 +22,7 @@ class AssertLegacyTraitConfiguration
      * @param bool   $processFirstArgumentOnly toggle to reduce the number of arguments passed to 1
      * @param string $declaringSource          the class that declares the deprecated method
      */
-    public function __construct(string $deprecatedMethodName, string $methodName, string $comment = '', bool $isAssertSessionMethod = true, bool $processFirstArgumentOnly = false, string $declaringSource = 'Drupal\FunctionalTests\AssertLegacyTrait', string $prependArgument = null)
+    public function __construct(string $deprecatedMethodName, string $methodName, string $comment = '', bool $isAssertSessionMethod = true, bool $processFirstArgumentOnly = false, string $declaringSource = 'Drupal\FunctionalTests\AssertLegacyTrait', ?string $prependArgument = null)
     {
         $this->deprecatedMethodName = $deprecatedMethodName;
         $this->methodName = $methodName;
diff --git a/src/Rector/PHPUnit/ShouldCallParentMethodsRector.php b/src/Rector/PHPUnit/ShouldCallParentMethodsRector.php
index 934ef7fa..d142d486 100644
--- a/src/Rector/PHPUnit/ShouldCallParentMethodsRector.php
+++ b/src/Rector/PHPUnit/ShouldCallParentMethodsRector.php
@@ -25,7 +25,7 @@ public function getNodeTypes(): array
      * @param Node  $node
      * @param Scope $scope
      *
-     * @return \PhpParser\Node|null
+     * @return Node|null
      */
     public function refactorWithScope(Node $node, Scope $scope)
     {
diff --git a/src/Utility/GetDeclaringSourceTrait.php b/src/Utility/GetDeclaringSourceTrait.php
index 24dcd56c..1a4ce402 100644
--- a/src/Utility/GetDeclaringSourceTrait.php
+++ b/src/Utility/GetDeclaringSourceTrait.php
@@ -14,7 +14,7 @@ trait GetDeclaringSourceTrait
     /**
      * Gets a method or property's declaring source (trait or class.).
      *
-     * @param node\Expr\MethodCall|Node\Expr\PropertyFetch $expr
+     * @param Node\Expr\MethodCall|Node\Expr\PropertyFetch $expr
      *                                                           The expression
      *
      * @return string|null