DPL: hide helper in an anonymous namespace (#13644)

Author: ktf

Framework/Foundation/include/Framework/StructToTuple.h

@@ -14,23 +14,26 @@
 #include <Framework/Traits.h>
 #include <array>
 
-namespace o2::framework
+namespace
 {
-struct any_type {
-  template <class T>
-  constexpr operator T(); // non explicit
-};
-
 template <class T, typename... Args>
 decltype(void(T{std::declval<Args>()...}), std::true_type())
-  test(int);
+  brace_test(int);
 
 template <class T, typename... Args>
 std::false_type
-  test(...);
+  brace_test(...);
+} // namespace
+
+namespace o2::framework
+{
+struct any_type {
+  template <class T>
+  constexpr operator T(); // non explicit
+};
 
 template <class T, typename... Args>
-struct is_braces_constructible : decltype(test<T, Args...>(0)) {
+struct is_braces_constructible : decltype(brace_test<T, Args...>(0)) {
 };
 
 #define DPL_REPEAT_0(x)