From d5144d8e7519d75b0bed6b70660b95eea18aed2a Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Thu, 16 Nov 2017 01:46:20 +0100
Subject: [PATCH] Restore GCC compatibility

---
 generator/tests/structs.h |  7 ++++---
 lib/json/reflector.h      | 12 ++++++++++--
 lib/json/serializable.h   | 12 +++---------
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/generator/tests/structs.h b/generator/tests/structs.h
index 259c532..3fce9b4 100644
--- a/generator/tests/structs.h
+++ b/generator/tests/structs.h
@@ -1,12 +1,12 @@
 #ifndef REFLECTIVE_RAPIDJSON_TESTS_STRUCTS_H
 #define REFLECTIVE_RAPIDJSON_TESTS_STRUCTS_H
 
-#include "../../lib/json/reflector-chronoutilities.h"
-#include "../../lib/json/serializable.h"
-
 #include <c++utilities/chrono/datetime.h>
 #include <c++utilities/chrono/timespan.h>
 
+#include "../../lib/json/reflector-chronoutilities.h"
+#include "../../lib/json/serializable.h"
+
 #include <deque>
 #include <list>
 #include <string>
@@ -38,6 +38,7 @@ class JsonGeneratorTests;
  */
 struct NestedTestStruct : public JsonSerializable<NestedTestStruct> {
     REFLECTIVE_RAPIDJSON_ENABLE_PRIVATE_MEMBERS(NestedTestStruct);
+
     friend class JsonGeneratorTests;
 
     list<vector<TestStruct>> nested;
diff --git a/lib/json/reflector.h b/lib/json/reflector.h
index 938a91a..18ad0a7 100644
--- a/lib/json/reflector.h
+++ b/lib/json/reflector.h
@@ -27,7 +27,14 @@
 namespace ReflectiveRapidJSON {
 
 template <typename Type> struct JsonSerializable;
-template <typename Type> struct AdaptedJsonSerializable;
+
+/*!
+ * \brief The AdaptedJsonSerializable class allows considering 3rd party classes as serializable.
+ */
+template <typename T> struct AdaptedJsonSerializable : public Traits::Bool<false> {
+    static constexpr const char *name = "AdaptedJsonSerializable";
+    static constexpr const char *qualifiedName = "ReflectiveRapidJSON::AdaptedJsonSerializable";
+};
 
 /*!
  * \brief The JsonReflector namespace contains helper functions to ease the use of RapidJSON for automatic (de)serialization.
@@ -75,7 +82,8 @@ using IsBuiltInType = Traits::Any<std::is_integral<Type>, std::is_floating_point
 template <typename Type> using IsCustomType = Traits::Not<IsBuiltInType<Type>>;
 
 // define trait to check for custom structs/classes which are JSON serializable
-template <typename Type> using IsJsonSerializable = Traits::Any<std::is_base_of<JsonSerializable<Type>, Type>, AdaptedJsonSerializable<Type>>;
+// NOTE: the check for Traits::IsComplete is required because std::is_base_of fails for incomplete types when using GCC
+template <typename Type> using IsJsonSerializable = Traits::Any<Traits::Not<Traits::IsComplete<Type>>, std::is_base_of<JsonSerializable<Type>, Type>, AdaptedJsonSerializable<Type>>;
 
 // define trait to check for map or hash
 template <typename Type>
diff --git a/lib/json/serializable.h b/lib/json/serializable.h
index 71a7468..1820f05 100644
--- a/lib/json/serializable.h
+++ b/lib/json/serializable.h
@@ -98,21 +98,15 @@ const JsonSerializable<Type> &as(const Type &serializable)
     return static_cast<const JsonSerializable<Type> &>(serializable);
 }
 
-/*!
- * \brief The AdaptedJsonSerializable class allows considering 3rd party classes as serializable.
- */
-template <typename T> struct AdaptedJsonSerializable : Traits::Bool<false> {
-    static constexpr const char *name = "AdaptedJsonSerializable";
-    static constexpr const char *qualifiedName = "ReflectiveRapidJSON::AdaptedJsonSerializable";
-};
-
 /*!
  * \def The REFLECTIVE_RAPIDJSON_MAKE_JSON_SERIALIZABLE macro allows to adapt (de)serialization for types defined in 3rd party header files.
  * \remarks The struct will not have the toJson() and fromJson() methods available. Use the corresponding functions in the namespace
  *          ReflectiveRapidJSON::JsonReflector instead.
+ * \todo GCC complains when putting :: before "ReflectiveRapidJSON" namespace: "global qualification of class name is invalid before ':' token"
+ *       Find out whether this is a compiler bug or a correct error message.
  */
 #define REFLECTIVE_RAPIDJSON_MAKE_JSON_SERIALIZABLE(T)                                                                                               \
-    template <> struct ::ReflectiveRapidJSON::AdaptedJsonSerializable<T> : Traits::Bool<true> {                                                      \
+    template <> struct ReflectiveRapidJSON::AdaptedJsonSerializable<T> : Traits::Bool<true> {                                                      \
     }
 
 /*!