Add protect_test2.cpp

test/Jamfile.v2

@@ -75,3 +75,4 @@ run bind_noexcept_mf_test.cpp ;
 run global_placeholders.cpp ;
 run mem_fn_noexcept_test.cpp ;
 run bind_cpp20_test.cpp ;
+run protect_test2.cpp ;

test/protect_test2.cpp

@@ -0,0 +1,26 @@
+// protect_test2.cpp
+//
+// Copyright 2020 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/bind/protect.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/core/is_same.hpp>
+
+template<class T, class F> void test( F )
+{
+    BOOST_TEST_TRAIT_TRUE((boost::core::is_same<typename T::result_type, typename F::result_type>));
+}
+
+struct X
+{
+    struct result_type {};
+};
+
+int main()
+{
+    test<X>( boost::protect( X() ) );
+
+    return boost::report_errors();
+}