diff --git a/src/Framework/MockObject/MockBuilder.php b/src/Framework/MockObject/MockBuilder.php
index 093a8ff55c4..d8cd0f4397a 100644
--- a/src/Framework/MockObject/MockBuilder.php
+++ b/src/Framework/MockObject/MockBuilder.php
@@ -180,8 +180,10 @@ public function setMethods(array $methods = null): self
 
     /**
      * Specifies the subset of methods to mock, requiring each to exist in the class
+     *
+     * @param string[] $methods
      */
-    public function setRealMethods(array $methods = null): self
+    public function setRealMethods(array $methods): self
     {
         if ($methods) {
             $reflection = new \ReflectionClass($this->type);