diff --git a/rules/PHPUnit80/Rector/MethodCall/SpecificAssertContainsRector.php b/rules/PHPUnit80/Rector/MethodCall/SpecificAssertContainsRector.php
index 57b276b8..6a8bf9ca 100644
--- a/rules/PHPUnit80/Rector/MethodCall/SpecificAssertContainsRector.php
+++ b/rules/PHPUnit80/Rector/MethodCall/SpecificAssertContainsRector.php
@@ -94,6 +94,10 @@ public function refactor(Node $node): ?Node
         }
 
         $methodName = $this->getName($node->name);
+        if ($methodName === null) {
+            return null;
+        }
+
         $newMethodName = self::OLD_TO_NEW_METHOD_NAMES[$methodName];
         $node->name = new Identifier($newMethodName);
 
diff --git a/rules/PHPUnit90/Rector/MethodCall/SpecificAssertContainsWithoutIdentityRector.php b/rules/PHPUnit90/Rector/MethodCall/SpecificAssertContainsWithoutIdentityRector.php
index 66a220cc..1ea76c92 100644
--- a/rules/PHPUnit90/Rector/MethodCall/SpecificAssertContainsWithoutIdentityRector.php
+++ b/rules/PHPUnit90/Rector/MethodCall/SpecificAssertContainsWithoutIdentityRector.php
@@ -117,6 +117,10 @@ public function refactor(Node $node): ?Node
         /* here we search for element of array without identity check  and we can replace functions */
         $methodName = $this->getName($node->name);
 
+        if ($methodName === null) {
+            return null;
+        }
+
         $node->name = new Identifier(self::OLD_METHODS_NAMES_TO_NEW_NAMES['string'][$methodName]);
         unset($node->args[3], $node->args[4]);