1 files changed, 19 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/core/when_valid.cpp b/src/boost/libs/hana/example/core/when_valid.cpp
new file mode 100644
index 000000000..2ed680fab
--- /dev/null
+++ b/src/boost/libs/hana/example/core/when_valid.cpp
@@ -0,0 +1,19 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/core/when.hpp>
+
+#include <type_traits>
+namespace hana = boost::hana;
+
+
+template <typename T, typename = hana::when<true>>
+struct base_template;
+
+template <typename T>
+struct base_template<T, hana::when_valid<typename T::value_type>> {
+    // something useful...
+};
+
+int main() { }