C++: Search both specified and unspecified type for iterators to not break Coding Standards.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/models/implementations/StdString.qll

@@ -66,7 +66,10 @@ abstract private class StdStringTaintFunction extends TaintFunction {
    * Gets the index of a parameter to this function that is an iterator.
    */
   final int getAnIteratorParameterIndex() {
-    this.getParameter(result).getUnspecifiedType() instanceof Iterator
+    exists(Parameter p |
+      p = this.getParameter(result) and
+      [p.getType(), p.getUnspecifiedType()] instanceof Iterator
+    )
   }
 }