[Fix] GCC compilation issue caused by template specialization (#287)

include/Async/Task.h

@@ -198,8 +198,10 @@ public:
         }
     };
 
-    template <>
-    struct promise_result<void> {
+    // WORKAROUND: GCC bug - full specialization in non-namespace scope not supported
+    // see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85282
+    template <std::same_as<void> V>
+    struct promise_result<V> {
         void return_void() noexcept {}
     };
 

include/Support/JSON.h

@@ -175,7 +175,7 @@ struct Serde<llvm::StringRef> {
     }
 };
 
-template <std::size_t N>
+template <unsigned N>
 struct Serde<llvm::SmallString<N>> {
     using V = llvm::SmallString<N>;
 

include/Support/Struct.h

@@ -300,7 +300,7 @@ template <typename... Ts>
 struct Struct<Inheritance<Ts...>> {
     constexpr inline static bool reflectable_struct = (refl::reflectable_struct<Ts> && ...);
 
-    constexpr static std::size_t member_count = (Struct<Ts>::member_count + ...);
+    constexpr static std::size_t member_count = (impl::member_count<Ts>() + ...);
 
     template <typename Object>
     constexpr static auto collect_members(Object&& object) {