highlight tuple parameter unpacking as error in Py3 code (http://www.python.org/dev/peps/pep-3113/)

python/src/com/jetbrains/python/PyBundle.properties

@@ -164,6 +164,7 @@ ANN.regular.param.after.vararg=regular parameter after * parameter
 ANN.regular.param.after.keyword=regular parameter after ** parameter
 ANN.non.default.param.after.default=non-default parameter follows default parameter
 ANN.named.arguments.after.star=named arguments must follow bare *
+ANN.tuple.py3=tuple parameter unpacking is not supported in Python 3
 
 ANN.star.import.at.top.only='import *' only allowed at module level
 

python/src/com/jetbrains/python/validation/ParameterListAnnotator.java

@@ -62,6 +62,14 @@ public class ParameterListAnnotator extends PyAnnotator {
           }
         }
 
+        @Override
+        public void enterTupleParameter(PyTupleParameter param, boolean first, boolean last) {
+          super.enterTupleParameter(param, first, last);
+          if (languageLevel.isPy3K()) {
+            markError(param, PyBundle.message("ANN.tuple.py3"));
+          }
+        }
+
         @Override
         public void visitSingleStarParameter(PySingleStarParameter param, boolean first, boolean last) {
           hadSingleStar = true;

python/testData/highlighting/keywordOnlyArguments.py

@@ -9,4 +9,6 @@ def keywordonly_sum_bad2(p1, *, <error descr="named arguments must follow bare *
 
 def keywordonly_and_kwarg_sum(*, k1, k2, **kwarg):
     return k1 + k2 + sum(kwarg.values())
-    
+
+def keywordonly_sum_bad2(p, *, <error descr="tuple parameter unpacking is not supported in Python 3">(k1, k2)</error>, **kw):
+    pass