SCARY/N2913 iterator support between the multi and non-multi versions of the associative and unordered containers.  I beleive lack of support for this was accidentally recently introduced (by me) and this is fixing a regression.  This time tests are put in to prevent such a regression in the future.

llvm-svn: 191692
diff --git a/libcxx/test/containers/associative/multiset/scary.pass.cpp b/libcxx/test/containers/associative/multiset/scary.pass.cpp
new file mode 100644
index 0000000..f5ee327
--- /dev/null
+++ b/libcxx/test/containers/associative/multiset/scary.pass.cpp
@@ -0,0 +1,24 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <set>
+
+// class set class multiset
+
+// Extension:  SCARY/N2913 iterator compatibility between set and multiset
+
+#include <set>
+
+int main()
+{
+    typedef std::set<int> M1;
+    typedef std::multiset<int> M2;
+    M2::iterator i;
+    M1::iterator j = i;
+}