diff --git a/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php b/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
index 2e8a703..47ab8a2 100644
--- a/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
+++ b/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
@@ -13,7 +13,7 @@ class FullyQualifiedSniff implements Sniff
      */
     public function register()
     {
-        return array(T_DOUBLE_COLON, T_NEW);
+        return array(T_DOUBLE_COLON, T_NEW, T_EXTENDS);
     }
 
     /**
@@ -43,11 +43,17 @@ private function getClassCall(File $phpcsFile, $stackPtr): string
 
         switch ($tokens[$stackPtr]['code']) {
             case T_NEW:
-                return $phpcsFile->getTokensAsString(
+                $tokensAsString = $phpcsFile->getTokensAsString(
                     $stackPtr,
                     $phpcsFile->findEndOfStatement($stackPtr) - $stackPtr
                 );
 
+                return substr(
+                    $tokensAsString,
+                    0,
+                    strpos($tokensAsString, '(')
+                );
+
             case T_DOUBLE_COLON:
                 $classCallStart = $phpcsFile->findStartOfStatement($stackPtr);
 
@@ -55,6 +61,18 @@ private function getClassCall(File $phpcsFile, $stackPtr): string
                     $classCallStart,
                     $stackPtr - $classCallStart
                 );
+
+            case T_EXTENDS:
+                $tokensAsString = $phpcsFile->getTokensAsString(
+                    $stackPtr,
+                    $phpcsFile->findEndOfStatement($stackPtr) - $stackPtr
+                );
+
+                return trim(substr(
+                    $tokensAsString,
+                    0,
+                    strpos($tokensAsString, '{')
+                ));
         }
 
         throw new RuntimeException(sprintf(
diff --git a/tests/rules/classes/allowed/FullyQualifiedSniff.php b/tests/rules/classes/allowed/FullyQualifiedSniff.php
index 43ed644..cbebc25 100644
--- a/tests/rules/classes/allowed/FullyQualifiedSniff.php
+++ b/tests/rules/classes/allowed/FullyQualifiedSniff.php
@@ -5,12 +5,20 @@
 namespace flyeralarm\Test;
 
 use RuntimeException;
+use stdClass;
 
-class FullyQualifiedSniff
+class FullyQualifiedSniff extends stdClass
 {
     public function a()
     {
         $className = RuntimeException::class;
         $a = new RuntimeException();
     }
+
+    public function b()
+    {
+        $a = new RuntimeException(
+            'We can\'t explain'
+        );
+    }
 }
diff --git a/tests/rules/classes/allowed/NamespaceVendorLowercasePackageUpperCamelCase.php b/tests/rules/classes/allowed/NamespaceVendorLowercasePackageUpperCamelCase.php
index b4ed219..8bd59de 100644
--- a/tests/rules/classes/allowed/NamespaceVendorLowercasePackageUpperCamelCase.php
+++ b/tests/rules/classes/allowed/NamespaceVendorLowercasePackageUpperCamelCase.php
@@ -4,6 +4,8 @@
 
 namespace flyeralarm\FooBar;
 
-class NamespaceVendorLowercasePackageUpperCamelCase extends \PHP_CodeSniffer_File
+use PHP_CodeSniffer_File;
+
+class NamespaceVendorLowercasePackageUpperCamelCase extends PHP_CodeSniffer_File
 {
 }
diff --git a/tests/rules/classes/not-allowed/FullyQualifiedSniff.php b/tests/rules/classes/not-allowed/FullyQualifiedSniff.php
index 720f040..0e7901d 100644
--- a/tests/rules/classes/not-allowed/FullyQualifiedSniff.php
+++ b/tests/rules/classes/not-allowed/FullyQualifiedSniff.php
@@ -1,6 +1,6 @@
 <?php
 
-// @expectedError Qualifier should be replaced with an import: "new \RuntimeException()"
+// @expectedError Qualifier should be replaced with an import: "new \RuntimeException"
 
 namespace flyeralarm\Test;
 
diff --git a/tests/rules/classes/not-allowed/FullyQualifiedSniffExtends.php b/tests/rules/classes/not-allowed/FullyQualifiedSniffExtends.php
new file mode 100644
index 0000000..b2c9af6
--- /dev/null
+++ b/tests/rules/classes/not-allowed/FullyQualifiedSniffExtends.php
@@ -0,0 +1,13 @@
+<?php
+
+// @expectedError Qualifier should be replaced with an import: "extends \stdClass"
+
+namespace flyeralarm\Test;
+
+class FullyQualifiedSniffExtends extends \stdClass
+{
+    public function a()
+    {
+        $a = 0;
+    }
+}