[c++] Broken move .ctor of bonded<Reader&>

When moving a bonded<> backed by a reference to a reader, the bonded<>
move ctor wasn't building with Clang and newer versions of MSVC. This
fixes that error by not calling std::move on the reference.

CHANGELOG.md

@@ -59,6 +59,7 @@ different versioning scheme, following the Haskell community's
 * Fixed a race condition when `bond::ext::gRPC::io_manager::shutdown` and
   `bond::ext::gRPC::io_manager::wait` are called concurrently.
 * Fixed a race condition during `bond::ext::gRPC::unary_call` destruction.
+* Fixed the broken move constructor of `bond::bonded<T, Reader&>`.
 
 ### C# ###
 

cpp/inc/bond/core/bonded.h

@@ -26,6 +26,24 @@ template <typename Protocols, typename Transform, typename T, typename Reader>
 typename boost::enable_if<need_double_pass<Transform>, bool>::type inline
 ApplyTransform(const Transform& transform, const bonded<T, Reader>& bonded);
 
+
+// Helper function move_data for dealing with [not] moving a Reader& in bonded<T, Reader&>
+template <typename T, typename U>
+typename boost::enable_if<std::is_reference<T>, T>::type
+inline move_data(U& data)
+{
+    BOOST_STATIC_ASSERT(std::is_same<T, U&>::value);
+    return data;
+}
+
+template <typename T, typename U>
+typename boost::disable_if<std::is_reference<T>, T&&>::type
+inline move_data(U& data)
+{
+    BOOST_STATIC_ASSERT(std::is_same<T, U>::value);
+    return std::move(data);
+}
+
 } // namespace detail
 
 
@@ -61,7 +79,7 @@ public:
     bonded(bonded&& bonded) BOND_NOEXCEPT_IF(
         std::is_nothrow_move_constructible<Reader>::value
         && std::is_nothrow_move_constructible<RuntimeSchema>::value)
-        : _data(std::move(bonded._data)),
+        : _data(detail::move_data<Reader>(bonded._data)),
           _schema(std::move(bonded._schema)),
           _skip(std::move(bonded._skip)),
           _base(std::move(bonded._base))

cpp/inc/bond/core/bonded_void.h

@@ -52,7 +52,7 @@ public:
     bonded(bonded&& other) BOND_NOEXCEPT_IF(
         std::is_nothrow_move_constructible<Reader>::value
         && std::is_nothrow_move_constructible<RuntimeSchema>::value)
-        : _data(std::move(other._data)),
+        : _data(detail::move_data<Reader>(other._data)),
           _schema(std::move(other._schema)),
           _skip(std::move(other._skip)),
           _base(std::move(other._base))