Remove constexpr from RecordComponent::visit() (#1582)

RecordComponent has a virtual base class, so it cannot be constexpr

Author: franzpoeschel

include/openPMD/RecordComponent.hpp

@@ -476,9 +476,8 @@ class RecordComponent : public BaseRecordComponent
      *         be implicitly converted.
      */
     template <typename Visitor, typename... Args>
-    constexpr auto visit(Args &&...args)
-        -> decltype(Visitor::template call<char>(
-            std::declval<RecordComponent &>(), std::forward<Args>(args)...));
+    auto visit(Args &&...args) -> decltype(Visitor::template call<char>(
+        std::declval<RecordComponent &>(), std::forward<Args>(args)...));
 
     static constexpr char const *const SCALAR = "\vScalar";
 

include/openPMD/RecordComponent.tpp

@@ -397,7 +397,7 @@ namespace detail
 } // namespace detail
 
 template <typename Visitor, typename... Args>
-constexpr auto RecordComponent::visit(Args &&...args)
+auto RecordComponent::visit(Args &&...args)
     -> decltype(Visitor::template call<char>(
         std::declval<RecordComponent &>(), std::forward<Args>(args)...))
 {