Issue 932. Checks for various named arguments cases.

tests/language/src/NamedParameters2Test.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// Dart test program for testing named parameters.
+// You may not provide the same parameter as both a positional and a named argument.
+
+int test(int a, [int b]) {
+  return a;
+}
+
+main() {
+  bool foundError = false;
+  try {
+    test(10, 25, b: 26);  // Parameter b passed twice, as positional and named.
+  } catch (Exception e) {
+    foundError = true;
+  }
+  Expect.equals(true, foundError);
+}