diff --git a/include/boost/system/detail/error_code.hpp b/include/boost/system/detail/error_code.hpp
index e434b42..18076cf 100644
--- a/include/boost/system/detail/error_code.hpp
+++ b/include/boost/system/detail/error_code.hpp
@@ -330,7 +330,7 @@ public:
     {
         if( flags_ != 1 )
         {
-            std::error_code e2 = *this;
+            std::error_code e2( *this );
             ::new( d2_ ) std::error_code( e2 );
             flags_ = 1;
         }
@@ -338,6 +338,14 @@ public:
         return *reinterpret_cast<std::error_code*>( d2_ );
     }
 
+#if defined(__clang__) && __clang_major__ < 7
+
+    template<class T,
+      class E = typename std::enable_if<std::is_same<T, std::error_code>::value>::type>
+      operator T const& () = delete;
+
+#endif
+
 #endif
 
     template<class Ch, class Tr>