The 'check-webkit-style' script misinterprets the following method declaration; void setOverlayMessage(ErrorString&, const String* const) final; It improperly believes that the second 'const' is a parameter name because it does not recognize that this is telling the compiler that the pointer cannot be changed: const String* immutableContents; // Declares a pointer whose contents cannot be changed. String* const immutablePointer; // Declares a pointer that cannot be changed. const String* const immutableContents; // Declares a pointer that cannot be changed, and whose contents cannot be changed.