Fixed an overload constraint issue in dart::object

include/dart.h

@@ -231,6 +231,24 @@ namespace dart {
       >
       explicit basic_object(Arg&& arg);
 
+      /**
+       *  @brief
+       *  Constructor allows an existing packet instance to be wrapped
+       *  under the strongly typed API.
+       *
+       *  @details
+       *  If the passed packet is not an object, will throw an exception.
+       */
+      template <class Arg,
+        std::enable_if_t<
+          std::is_same<
+            std::decay_t<Arg>,
+            Object
+          >::value
+        >* EnableIf = nullptr
+      >
+      explicit basic_object(Arg&& arg);
+
       /**
        *  @brief
        *  Function is responsible for forwarding any constructors
@@ -258,6 +276,11 @@ namespace dart {
             Arg,
             Object
           >::value
+          &&
+          !std::is_same<
+            std::decay_t<Arg>,
+            Object
+          >::value
         >* EnableIf = nullptr
       >
       basic_object(Arg&& arg);
@@ -4781,6 +4804,16 @@ namespace dart {
       >
       explicit basic_null(basic_null<N> const&) {}
 
+      /**
+       *  @brief
+       *  Constructor allows an existing packet instance to be wrapped
+       *  under the strongly typed API.
+       *
+       *  @details
+       *  If the passed packet is not a null, will throw an exception.
+       */
+      explicit basic_null(Null const& null);
+
       /**
        *  @brief
        *  Converting constructor to allow interoperability between underlying
@@ -5434,13 +5467,21 @@ namespace dart {
       operator view() const& noexcept;
       operator view() && = delete;
 
+      /**
+       *  @brief
+       *  Conversion operator to finalized type
+       */
+      explicit operator basic_buffer<RefCount>() const;
+
       /**
        *  @brief
        *  Generic conversion operator.
        */
       template <class T, class EnableIf =
         std::enable_if_t<
-          !meta::is_higher_specialization_of<T, basic_packet>::value
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
           &&
           convert::is_castable<basic_heap, T>::value
         >
@@ -5453,7 +5494,9 @@ namespace dart {
        */
       template <class T, class EnableIf =
         std::enable_if_t<
-          !meta::is_higher_specialization_of<T, basic_packet>::value
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
           &&
           convert::is_castable<basic_heap, T>::value
         >
@@ -8270,13 +8313,21 @@ namespace dart {
       operator view() const& noexcept;
       operator view() && = delete;
 
+      /**
+       *  @brief
+       *  Explicit conversion to non-finalized type
+       */
+      explicit operator basic_heap<RefCount>() const;
+
       /**
        *  @brief
        *  Generic conversion operator.
        */
       template <class T, class EnableIf =
         std::enable_if_t<
-          !meta::is_higher_specialization_of<T, basic_packet>::value
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
           &&
           convert::is_castable<basic_buffer, T>::value
         >
@@ -8289,7 +8340,9 @@ namespace dart {
        */
       template <class T, class EnableIf =
         std::enable_if_t<
-          !meta::is_higher_specialization_of<T, basic_packet>::value
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
           &&
           convert::is_castable<basic_buffer, T>::value
         >
@@ -10613,12 +10666,40 @@ namespace dart {
       operator view() const& noexcept;
       operator view() && = delete;
 
+      /**
+       *  @brief
+       *  Explicit conversion to non-finalized API.
+       */
+      explicit operator basic_heap<RefCount>() const&;
+
+      /**
+       *  @brief
+       *  Explicit conversion to non-finalized API.
+       */
+      explicit operator basic_heap<RefCount>() &&;
+
+      /**
+       *  @brief
+       *  Explicit conversion to finalized API.
+       */
+      explicit operator basic_buffer<RefCount>() const&;
+
+      /**
+       *  @brief
+       *  Explicit conversion to non-finalized API.
+       */
+      explicit operator basic_buffer<RefCount>() &&;
+
       /**
        *  @brief
        *  Generic conversion operator.
        */
       template <class T, class EnableIf =
         std::enable_if_t<
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
+          &&
           convert::is_castable<basic_packet, T>::value
         >
       >
@@ -10630,6 +10711,10 @@ namespace dart {
        */
       template <class T, class EnableIf =
         std::enable_if_t<
+          !detail::is_dart_type<T>::value
+          &&
+          !detail::is_wrapper_type<T>::value
+          &&
           convert::is_castable<basic_packet, T>::value
         >
       >

include/dart/api.tcc

@@ -13,6 +13,11 @@
 
 namespace dart {
 
+  template <class Null>
+  basic_null<Null>::basic_null(Null const& null) {
+    if (!null.is_null()) throw type_error("dart::packet::null can only be constructed as a null");
+  }
+
   template <class Object>
   template <class Key, class Value, class Comp, class Alloc, class EnableIf>
   basic_object<Object>& basic_object<Object>::operator =(std::map<Key, Value, Comp, Alloc> const& map) & {

include/dart/buffer/api.tcc

@@ -60,6 +60,11 @@ namespace dart {
     return tmp;
   }
 
+  template <template <class> class RefCount>
+  basic_buffer<RefCount>::operator basic_heap<RefCount>() const {
+    return convert::cast<basic_heap<RefCount>>(*this);
+  }
+
   template <template <class> class RefCount>
   template <class T, class EnableIf>
   basic_buffer<RefCount>::operator T() const& {

include/dart/heap/api.tcc

@@ -53,6 +53,11 @@ namespace dart {
     return view {detail::view_tag {}, data};
   }
 
+  template <template <class> class RefCount>
+  basic_heap<RefCount>::operator basic_buffer<RefCount>() const {
+    return convert::cast<basic_buffer<RefCount>>(*this);
+  }
+
   template <template <class> class RefCount>
   template <class T, class EnableIf>
   basic_heap<RefCount>::operator T() const& {

include/dart/object.tcc

@@ -32,6 +32,19 @@ namespace dart {
     ensure_object("dart::packet::object can only be constructed as an object");
   }
 
+  template <class Object>
+  template <class Arg,
+    std::enable_if_t<
+      std::is_same<
+        std::decay_t<Arg>,
+        Object
+      >::value
+    >* EnableIf
+  >
+  basic_object<Object>::basic_object(Arg&& arg) : val(std::forward<Arg>(arg)) {
+    ensure_object("dart::packet::object can only be constructed as an object");
+  }
+
   template <class Object>
   template <class Arg,
     std::enable_if_t<
@@ -43,6 +56,11 @@ namespace dart {
         Arg,
         Object
       >::value
+      &&
+      !std::is_same<
+        std::decay_t<Arg>,
+        Object
+      >::value
     >* EnableIf
   >
   basic_object<Object>::basic_object(Arg&& arg) : val(std::forward<Arg>(arg)) {

include/dart/packet/api.tcc

@@ -45,6 +45,26 @@ namespace dart {
     }, impl);
   }
 
+  template <template <class> class RefCount>
+  basic_packet<RefCount>::operator basic_heap<RefCount>() const& {
+    return convert::cast<basic_heap<RefCount>>(*this);
+  }
+
+  template <template <class> class RefCount>
+  basic_packet<RefCount>::operator basic_heap<RefCount>() && {
+    return convert::cast<basic_heap<RefCount>>(std::move(*this));
+  }
+
+  template <template <class> class RefCount>
+  basic_packet<RefCount>::operator basic_buffer<RefCount>() const& {
+    return convert::cast<basic_buffer<RefCount>>(*this);
+  }
+
+  template <template <class> class RefCount>
+  basic_packet<RefCount>::operator basic_buffer<RefCount>() && {
+    return convert::cast<basic_buffer<RefCount>>(std::move(*this));
+  }
+
   template <template <class> class RefCount>
   template <class T, class EnableIf>
   basic_packet<RefCount>::operator T() const& {