Revert "Swift: use C++20 constraints and concepts to simplify code"

swift/extractor/trap/TrapLabel.h

@@ -9,7 +9,6 @@
 #include <binlog/binlog.hpp>
 #include <cmath>
 #include <charconv>
-#include <concepts>
 
 namespace codeql {
 
@@ -83,8 +82,9 @@ class TrapLabel : public UntypedTrapLabel {
   static TrapLabel unsafeCreateFromUntyped(UntypedTrapLabel label) { return TrapLabel{label.id_}; }
 
   template <typename SourceTag>
-  requires std::derived_from<SourceTag, Tag> TrapLabel(const TrapLabel<SourceTag>& other)
-      : UntypedTrapLabel(other) {}
+  TrapLabel(const TrapLabel<SourceTag>& other) : UntypedTrapLabel(other) {
+    static_assert(std::is_base_of_v<Tag, SourceTag>, "wrong label assignment!");
+  }
 };
 
 // wrapper class to allow directly assigning a vector of TrapLabel<A> to a vector of
@@ -96,8 +96,8 @@ struct TrapLabelVectorWrapper {
   std::vector<TrapLabel<TagParam>> data;
 
   template <typename DestinationTag>
-  requires std::derived_from<Tag, DestinationTag>
   operator std::vector<TrapLabel<DestinationTag>>() && {
+    static_assert(std::is_base_of_v<DestinationTag, Tag>, "wrong label assignment!");
     // reinterpret_cast is safe because TrapLabel instances differ only on the type, not the
     // underlying data
     return std::move(reinterpret_cast<std::vector<TrapLabel<DestinationTag>>&>(data));