Python: Fix for-iteration of tuples

python/ql/src/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -1508,6 +1508,8 @@ predicate forReadStep(CfgNode nodeFrom, Content c, Node nodeTo) {
     c instanceof ListElementContent
     or
     c instanceof SetElementContent
+    or
+    c instanceof TupleElementContent
   )
 }
 

python/ql/src/semmle/python/dataflow/new/internal/DataFlowPublic.qll

@@ -544,7 +544,12 @@ newtype TContent =
   /** An element of a set. */
   TSetElementContent() or
   /** An element of a tuple at a specific index. */
-  TTupleElementContent(int index) { exists(any(TupleNode tn).getElement(index)) } or
+  TTupleElementContent(int index) {
+    exists(any(TupleNode tn).getElement(index))
+    or
+    // Arguments can overflow and end up in the starred parameter tuple.
+    exists(any(CallNode cn).getArg(index))
+  } or
   /** An element of a dictionary under a specific key. */
   TDictionaryElementContent(string key) {
     key = any(KeyValuePair kvp).getKey().(StrConst).getS()