Update in-place make_unexpected, add it for use with std::expected, a…

…dd test

include/nonstd/expected.hpp

@@ -248,6 +248,19 @@ namespace nonstd {
     {
         return unexpected< typename std::decay<E>::type >( std::forward<E>(value) );
     }
+
+    template
+    <
+        typename E, typename... Args,
+        typename = std::enable_if<
+            std::is_constructible<E, Args...>::value
+        >
+    >
+    constexpr auto
+    make_unexpected( std::in_place_t inplace, Args &&... args ) -> unexpected_type< typename std::decay<E>::type >
+    {
+        return unexpected_type< typename std::decay<E>::type >( inplace, std::forward<Args>(args)...);
+    }
 }  // namespace nonstd
 
 #else // nsel_USES_STD_EXPECTED
@@ -1575,9 +1588,11 @@ template
     >
 >
 nsel_constexpr14 auto
-make_unexpected( in_place_t inplace, Args... args ) -> unexpected_type< typename std::decay<E> >
+make_unexpected( nonstd_lite_in_place_t(E), Args &&... args ) -> unexpected_type< typename std::decay<E>::type >
 {
-    return unexpected_type< typename std::decay<E>::type >( inplace, std::forward<Args>(args)...);
+    return std::forward< unexpected_type< typename std::decay<E>::type > >(
+        unexpected_type< typename std::decay<E>::type >( nonstd_lite_in_place(E), std::forward<Args>(args)...)
+    );
 }
 
 #if nsel_P0323R <= 3

test/expected.t.cpp

@@ -566,6 +566,17 @@ CASE( "make_unexpected(): Allows to create an unexpected_type<E> from an E" )
     EXPECT( u.error() == error );
 }
 
+CASE( "make_unexpected(): Allows to in-place create an unexpected_type<E> from an E" )
+{
+    const auto a = 'a';
+    const auto b =  7;
+
+    auto u = make_unexpected< std::pair<char, int> >( in_place, a, b );
+
+    EXPECT( u.error().first  == a );
+    EXPECT( u.error().second == b );
+}
+
 CASE( "make_unexpected_from_current_exception(): Allows to create an unexpected_type<std::exception_ptr> from the current exception" "[.deprecated]" )
 {
 #if nsel_P0323R <= 2