Index: include/iterator
===================================================================
--- include/iterator
+++ include/iterator
@@ -1112,6 +1112,8 @@
 >::type
 __unwrap_iter(__wrap_iter<_Tp*>);
 
+template <class _Tp, class _Alloc> class _LIBCPP_TYPE_VIS_ONLY vector;
+
 template <class _Iter>
 class __wrap_iter
 {
Index: test/std/iterators/iterators.general/gcc_workaround.pass.cpp
===================================================================
--- test/std/iterators/iterators.general/gcc_workaround.pass.cpp
+++ test/std/iterators/iterators.general/gcc_workaround.pass.cpp
@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// Tests workaround for  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64816.
+
+#include <string>
+
+void f(const std::string &s) { s.begin(); }
+
+#include <vector>
+
+void AppendTo(const std::vector<char> &v) { v.begin(); }
+
+int main() {}