diff --git a/src/openrct2/localisation/Localisation.h b/src/openrct2/localisation/Localisation.h
index e5778bbb75..de210126e0 100644
--- a/src/openrct2/localisation/Localisation.h
+++ b/src/openrct2/localisation/Localisation.h
@@ -131,6 +131,23 @@ public:
     {
         static_assert(sizeof(TSpecified) <= sizeof(uintptr_t), "Type too large");
         static_assert(sizeof(TDeduced) <= sizeof(uintptr_t), "Type too large");
+
+        // clang-format off
+        static_assert(
+            std::is_same_v<TSpecified, char*> ||
+            std::is_same_v<TSpecified, const char*> ||
+            std::is_same_v<TSpecified, int16_t> ||
+            std::is_same_v<TSpecified, int32_t> ||
+            std::is_same_v<TSpecified, money32> ||
+            std::is_same_v<TSpecified, rct_string_id> ||
+            std::is_same_v<TSpecified, uint8_t*> ||
+            std::is_same_v<TSpecified, uint16_t> ||
+            std::is_same_v<TSpecified, uint32_t> ||
+            std::is_same_v<TSpecified, utf8*> ||
+            std::is_same_v<TSpecified, const utf8*>
+        );
+        // clang-format on
+
         uintptr_t convertedValue;
         if constexpr (std::is_integral_v<TSpecified>)
         {