PY-4082: correctly map things like (*args, a=... b=...) in Py3k.

python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java

@@ -455,8 +455,10 @@ public class PyCallExpressionHelper {
           if (n_par.isPositionalContainer()) tuple_par = n_par;
           else if (n_par.isKeywordContainer()) kwd_par = n_par;
           else {
-            slots.put(n_par, null); // regular parameter that may serve as positional
-            positional_index += 1;
+            slots.put(n_par, null); // regular parameter that may serve as positional/named
+            if (tuple_par == null && kwd_par == null) {
+              positional_index += 1; // only if we're not past *param / **param
+            }
           }
         }
         else {

python/testData/paramInfo/Py3kPastTupleArg.py

@@ -0,0 +1,4 @@
+def foo(*arg, a=1, b=2):
+  pass
+
+foo(<arg1>1, <arg2>2, <arg3>b=10, <arg4>a=20)

python/testSrc/com/jetbrains/python/PyParameterInfoTest.java

@@ -356,6 +356,14 @@ public class PyParameterInfoTest extends LightMarkedTestCase {
     feignCtrlP(marks.get("<arg2>").getTextOffset()).check("a, b, c=1, d=2, e=3", new String[]{}); // no logical next
   }
 
+  public void testPy3kPastTupleArg() {
+    Map<String, PsiElement> marks = loadTest(4);
+    feignCtrlP(marks.get("<arg1>").getTextOffset()).check("*arg, a=1, b=2", new String[]{"*arg, "});
+    feignCtrlP(marks.get("<arg2>").getTextOffset()).check("*arg, a=1, b=2", new String[]{"*arg, "});
+    feignCtrlP(marks.get("<arg3>").getTextOffset()).check("*arg, a=1, b=2", new String[]{"b=2"});
+    feignCtrlP(marks.get("<arg4>").getTextOffset()).check("*arg, a=1, b=2", new String[]{"a=1, "});
+  }
+
   /**
    * Imitates pressing of Ctrl+P; fails if results are not as expected.
    * @param offset offset of 'cursor' where ^P is pressed.