Implement import scope

tests/language/library6.dart

+// Copyright (c) 2012, 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.
+
+// This tests that it is a compile-time error to both import a library
+// that defines a function type alias and to have a local definition for
+// another function type alias with the same name.
+// This name conflict is considered an error even if Fun is never referred to.
+
+#library("Library6NegativeTest.dart");
+#import("library5a.dart");  // Defines function type alias Fun
+
+typedef int Fun();  // Does not conflict with definition of Fun from library5a
+
+main() {
+}
+