specialization concept

Author: aalkin

DataFormats/simulation/include/SimulationDataFormat/ConstMCTruthContainer.h

@@ -116,6 +116,7 @@ class ConstMCTruthContainer : public std::vector<char>
 #ifndef GPUCA_STANDALONE
 namespace o2::framework
 {
+// FIXME: this is potentially dangerous
 template <typename T>
 struct is_specialization<o2::dataformats::ConstMCTruthContainer<T>, std::vector> : std::true_type {
 };

Framework/Core/include/Framework/DataAllocator.h

@@ -179,8 +179,7 @@ class DataAllocator
       .get();
   }
 
-  template <typename T, typename... Args>
-    requires VectorOfMessageableTypes<T>
+  template <VectorOfMessageableTypes T, typename... Args>
   decltype(auto) make(const Output& spec, Args... args)
   {
     auto& timingInfo = mRegistry.get<TimingInfo>();

Framework/Foundation/include/Framework/Traits.h

@@ -12,6 +12,7 @@
 #define O2_FRAMEWORK_TRAITS_H_
 
 #include <type_traits>
+#include <concepts>
 
 namespace o2::framework
 {
@@ -30,6 +31,11 @@ struct is_specialization<Ref<Args...>, Ref> : std::true_type {
 template <typename T, template <typename...> class Ref>
 inline constexpr bool is_specialization_v = is_specialization<T, Ref>::value;
 
+template <template <typename...> typename B, typename S>
+concept specialization = requires {
+  {[]<typename... Ts>(B<Ts...>*) -> B<Ts...> {}(std::declval<S*>())} -> std::same_as<S>;
+};
+
 template <typename A, typename B>
 struct is_overriding : public std::bool_constant<std::is_same_v<A, B> == false && std::is_member_function_pointer_v<A> && std::is_member_function_pointer_v<B>> {
 };