diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 874f504ab..f9539843b 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -55,7 +55,7 @@ inline std::unordered_map<std::type_index, std::uint64_t> &odr_guard_registry()
 namespace {
 
 template <typename IntrinsicType>
-bool odr_guard_impl(const std::type_index & it_ti, const std::uint64_t& tc_id) {
+bool odr_guard_impl(const std::type_index &it_ti, const std::uint64_t &tc_id) {
     printf("\nLOOOK %s %llu\n", type_id<IntrinsicType>().c_str(), (long long) tc_id);
     fflush(stdout);
     auto [reg_iter, added] = odr_guard_registry().insert({it_ti, tc_id});
@@ -73,10 +73,9 @@ struct type_caster_odr_guard : type_caster<IntrinsicType> {
 };
 
 template <typename IntrinsicType>
-int type_caster_odr_guard<IntrinsicType>::translation_unit_local = [](){
-    odr_guard_impl<IntrinsicType>(
-        std::type_index(typeid(IntrinsicType)),
-        type_caster<IntrinsicType>::universally_unique_identifier);
+int type_caster_odr_guard<IntrinsicType>::translation_unit_local = []() {
+    odr_guard_impl<IntrinsicType>(std::type_index(typeid(IntrinsicType)),
+                                  type_caster<IntrinsicType>::universally_unique_identifier.value);
     return 0;
 }();
 
@@ -85,6 +84,10 @@ int type_caster_odr_guard<IntrinsicType>::translation_unit_local = [](){
 template <typename type>
 using make_caster = type_caster_odr_guard<intrinsic_t<type>>;
 
+#define PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(...)                            \
+    if (::pybind11::detail::make_caster<__VA_ARGS__>::translation_unit_local) {                   \
+    }
+
 template <typename T>
 struct type_uses_smart_holder_type_caster {
     static constexpr bool value
@@ -94,15 +97,13 @@ struct type_uses_smart_holder_type_caster {
 // Shortcut for calling a caster's `cast_op_type` cast operator for casting a type_caster to a T
 template <typename T>
 typename make_caster<T>::template cast_op_type<T> cast_op(make_caster<T> &caster) { // LOOOK
-    if (make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     return caster.operator typename make_caster<T>::template cast_op_type<T>();
 }
 template <typename T>
 typename make_caster<T>::template cast_op_type<typename std::add_rvalue_reference<T>::type>
 cast_op(make_caster<T> &&caster) { // LOOOK
-    if (make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     return std::move(caster).operator typename make_caster<T>::
         template cast_op_type<typename std::add_rvalue_reference<T>::type>();
 }
@@ -124,7 +125,7 @@ private:
 public:
     bool load(handle src, bool convert) { return subcaster.load(src, convert); }
     static constexpr auto name = caster_t::name;
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     static handle
     cast(const std::reference_wrapper<type> &src, return_value_policy policy, handle parent) {
         // It is definitely wrong to take ownership of this pointer, so mask that rvp
@@ -296,7 +297,7 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(T, const_name<std::is_integral<T>::value>("int", "float"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename T>
@@ -312,7 +313,7 @@ public:
         return none().inc_ref();
     }
     PYBIND11_TYPE_CASTER(T, const_name("None"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <>
@@ -360,7 +361,7 @@ public:
     using cast_op_type = void *&;
     explicit operator void *&() { return value; }
     static constexpr auto name = const_name("capsule");
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
 private:
     void *value = nullptr;
@@ -417,7 +418,7 @@ public:
         return handle(src ? Py_True : Py_False).inc_ref();
     }
     PYBIND11_TYPE_CASTER(bool, const_name("bool"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 // Helper class for UTF-{8,16,32} C++ stl strings:
@@ -510,7 +511,7 @@ struct string_caster {
     }
 
     PYBIND11_TYPE_CASTER(StringType, const_name(PYBIND11_STRING_NAME));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
 private:
     static handle decode_utfN(const char *buffer, ssize_t nbytes) {
@@ -683,7 +684,7 @@ public:
     }
 
     static constexpr auto name = const_name(PYBIND11_STRING_NAME);
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     template <typename _T>
     using cast_op_type = pybind11::detail::cast_op_type<_T>;
 };
@@ -728,7 +729,7 @@ public:
 
     static constexpr auto name
         = const_name("Tuple[") + concat(make_caster<Ts>::name...) + const_name("]");
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     template <typename T>
     using cast_op_type = type;
@@ -901,7 +902,7 @@ struct move_only_holder_caster {
         return type_caster_base<type>::cast_holder(ptr, std::addressof(src));
     }
     static constexpr auto name = type_caster_base<type>::name;
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 #ifndef PYBIND11_USE_SMART_HOLDER_AS_DEFAULT
@@ -1011,7 +1012,7 @@ struct pyobject_caster {
         return src.inc_ref();
     }
     PYBIND11_TYPE_CASTER(type, handle_type_name<type>::name);
-    static constexpr std::uint64_t universally_unique_identifier = 3434;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(3434)
 };
 
 template <typename T>
@@ -1106,8 +1107,7 @@ type_caster<T, SFINAE> &load_type(type_caster<T, SFINAE> &conv, const handle &ha
 // Wrapper around the above that also constructs and returns a type_caster
 template <typename T>
 make_caster<T> load_type(const handle &handle) {
-    if (make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     make_caster<T> conv;
     load_type(conv, handle);
     return conv;
@@ -1145,8 +1145,7 @@ object cast(T &&value,
                  : std::is_lvalue_reference<T>::value ? return_value_policy::copy
                                                       : return_value_policy::move;
     }
-    if (detail::make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     return reinterpret_steal<object>(
         detail::make_caster<T>::cast(std::forward<T>(value), policy, parent));
 }
@@ -1247,8 +1246,7 @@ using override_caster_t = conditional_t<cast_is_temporary_value_reference<ret_ty
 template <typename T>
 enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&o,
                                                                      make_caster<T> &caster) {
-    if (make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     return cast_op<T>(load_type(caster, o));
 }
 template <typename T>
@@ -1360,8 +1358,7 @@ private:
           type(type_id<T>())
 #endif
     {
-        if (detail::make_caster<T>::translation_unit_local) {
-        }
+        PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
         // Workaround! See:
         // https://github.com/pybind/pybind11/issues/2336
         // https://github.com/pybind/pybind11/pull/2685#issuecomment-731286700
@@ -1592,8 +1589,7 @@ public:
 private:
     template <typename T>
     void process(list &args_list, T &&x) {
-        if (make_caster<T>::translation_unit_local) {
-        }
+        PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
         auto o = reinterpret_steal<object>(
             detail::make_caster<T>::cast(std::forward<T>(x), policy, {}));
         if (!o) {
@@ -1738,8 +1734,7 @@ handle type::handle_of() {
                        detail::type_uses_smart_holder_type_caster<T>>::value,
         "py::type::of<T> only supports the case where T is a registered C++ types.");
 
-    if (detail::make_caster<T>::translation_unit_local) {
-    }
+    PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
     return detail::get_type_handle(typeid(T), true);
 }
 
diff --git a/include/pybind11/chrono.h b/include/pybind11/chrono.h
index 6342f0ab6..971802846 100644
--- a/include/pybind11/chrono.h
+++ b/include/pybind11/chrono.h
@@ -97,7 +97,7 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(type, const_name("datetime.timedelta"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 inline std::tm *localtime_thread_safe(const std::time_t *time, std::tm *buf) {
@@ -209,7 +209,7 @@ public:
                                           us.count());
     }
     PYBIND11_TYPE_CASTER(type, const_name("datetime.datetime"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 // Other clocks that are not the system clock are not measured as datetime.datetime objects
diff --git a/include/pybind11/complex.h b/include/pybind11/complex.h
index 118f7073e..27cead1cc 100644
--- a/include/pybind11/complex.h
+++ b/include/pybind11/complex.h
@@ -69,7 +69,7 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(std::complex<T>, const_name("complex"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 PYBIND11_NAMESPACE_END(detail)
 PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/detail/init.h b/include/pybind11/detail/init.h
index 8e383e48d..dee0b04b7 100644
--- a/include/pybind11/detail/init.h
+++ b/include/pybind11/detail/init.h
@@ -27,7 +27,7 @@ public:
     using cast_op_type = value_and_holder &;
     explicit operator value_and_holder &() { return *value; }
     static constexpr auto name = const_name<value_and_holder>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
 private:
     value_and_holder *value = nullptr;
diff --git a/include/pybind11/detail/smart_holder_type_casters.h b/include/pybind11/detail/smart_holder_type_casters.h
index dedfad0a1..b8152aa2a 100644
--- a/include/pybind11/detail/smart_holder_type_casters.h
+++ b/include/pybind11/detail/smart_holder_type_casters.h
@@ -616,7 +616,7 @@ template <typename T>
 struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
                                   smart_holder_type_caster_class_hooks {
     static constexpr auto name = const_name<T>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     // static handle cast(T, ...)
     // is redundant (leads to ambiguous overloads).
@@ -778,7 +778,7 @@ template <typename T>
 struct smart_holder_type_caster<std::shared_ptr<T>> : smart_holder_type_caster_load<T>,
                                                       smart_holder_type_caster_class_hooks {
     static constexpr auto name = const_name<T>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     static handle cast(const std::shared_ptr<T> &src, return_value_policy policy, handle parent) {
         switch (policy) {
@@ -843,7 +843,7 @@ template <typename T>
 struct smart_holder_type_caster<std::shared_ptr<T const>> : smart_holder_type_caster_load<T>,
                                                             smart_holder_type_caster_class_hooks {
     static constexpr auto name = const_name<T>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     static handle
     cast(const std::shared_ptr<T const> &src, return_value_policy policy, handle parent) {
@@ -864,7 +864,7 @@ template <typename T, typename D>
 struct smart_holder_type_caster<std::unique_ptr<T, D>> : smart_holder_type_caster_load<T>,
                                                          smart_holder_type_caster_class_hooks {
     static constexpr auto name = const_name<T>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     static handle cast(std::unique_ptr<T, D> &&src, return_value_policy policy, handle parent) {
         if (policy != return_value_policy::automatic
@@ -948,7 +948,7 @@ template <typename T, typename D>
 struct smart_holder_type_caster<std::unique_ptr<T const, D>>
     : smart_holder_type_caster_load<T>, smart_holder_type_caster_class_hooks {
     static constexpr auto name = const_name<T>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     static handle
     cast(std::unique_ptr<T const, D> &&src, return_value_policy policy, handle parent) {
diff --git a/include/pybind11/detail/type_caster_base.h b/include/pybind11/detail/type_caster_base.h
index 3e2590bf9..2629fd709 100644
--- a/include/pybind11/detail/type_caster_base.h
+++ b/include/pybind11/detail/type_caster_base.h
@@ -904,6 +904,17 @@ struct polymorphic_type_hook : public polymorphic_type_hook_base<itype> {};
 
 PYBIND11_NAMESPACE_BEGIN(detail)
 
+namespace {
+template <std::uint64_t Value>
+struct universally_unique_identifier_holder {
+    static constexpr std::uint64_t value = Value;
+};
+} // namespace
+
+#define PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(...)                                               \
+    static constexpr ::pybind11::detail::universally_unique_identifier_holder<__VA_ARGS__>        \
+        universally_unique_identifier;
+
 /// Generic type caster for objects stored on the heap
 template <typename type>
 class type_caster_base : public type_caster_generic {
@@ -911,7 +922,7 @@ class type_caster_base : public type_caster_generic {
 
 public:
     static constexpr auto name = const_name<type>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     type_caster_base() : type_caster_base(typeid(type)) {}
     explicit type_caster_base(const std::type_info &info) : type_caster_generic(info) {}
diff --git a/include/pybind11/eigen.h b/include/pybind11/eigen.h
index 41dd2496c..b5096b5c7 100644
--- a/include/pybind11/eigen.h
+++ b/include/pybind11/eigen.h
@@ -392,7 +392,7 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     // NOLINTNEXTLINE(google-explicit-constructor)
     operator Type *() { return &value; }
@@ -437,7 +437,7 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     // Explicitly delete these: support python -> C++ conversion on these (i.e. these can be return
     // types but not bound arguments).  We still provide them (with an explicitly delete) so that
@@ -625,7 +625,7 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     // Explicitly delete these: support python -> C++ conversion on these (i.e. these can be return
     // types but not bound arguments).  We still provide them (with an explicitly delete) so that
@@ -702,7 +702,7 @@ struct type_caster<Type, enable_if_t<is_eigen_sparse<Type>::value>> {
                          const_name<(Type::IsRowMajor) != 0>("scipy.sparse.csr_matrix[",
                                                              "scipy.sparse.csc_matrix[")
                              + npy_format_descriptor<Scalar>::name + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 PYBIND11_NAMESPACE_END(detail)
diff --git a/include/pybind11/functional.h b/include/pybind11/functional.h
index 8c4e3d5ea..5fc5fb317 100644
--- a/include/pybind11/functional.h
+++ b/include/pybind11/functional.h
@@ -124,7 +124,7 @@ public:
                          const_name("Callable[[") + concat(make_caster<Args>::name...)
                              + const_name("], ") + make_caster<retval_type>::name
                              + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 PYBIND11_NAMESPACE_END(detail)
diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index 6611387ce..de74f8023 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -1214,7 +1214,7 @@ struct pyobject_caster<array_t<T, ExtraFlags>> {
         return src.inc_ref();
     }
     PYBIND11_TYPE_CASTER(type, handle_type_name<type>::name);
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename T>
diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
index af96dec4d..8196f2b50 100644
--- a/include/pybind11/stl.h
+++ b/include/pybind11/stl.h
@@ -87,7 +87,7 @@ struct set_caster {
     }
 
     PYBIND11_TYPE_CASTER(type, const_name("Set[") + key_conv::name + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename Type, typename Key, typename Value>
@@ -137,7 +137,7 @@ struct map_caster {
     PYBIND11_TYPE_CASTER(Type,
                          const_name("Dict[") + key_conv::name + const_name(", ") + value_conv::name
                              + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename Type, typename Value>
@@ -190,7 +190,7 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(Type, const_name("List[") + value_conv::name + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename Type, typename Alloc>
@@ -260,7 +260,7 @@ public:
                                                      const_name("[") + const_name<Size>()
                                                          + const_name("]"))
                              + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 template <typename Type, size_t Size>
@@ -319,7 +319,7 @@ struct optional_caster {
     }
 
     PYBIND11_TYPE_CASTER(Type, const_name("Optional[") + value_conv::name + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 #if defined(PYBIND11_HAS_OPTIONAL)
@@ -349,8 +349,7 @@ struct variant_caster_visitor {
 
     template <typename T>
     result_type operator()(T &&src) const {
-        if (make_caster<T>::translation_unit_local) {
-        }
+        PYBIND11_DETAIL_TYPE_CASTER_ACCESS_TRANSLATION_UNIT_LOCAL(T)
         return make_caster<T>::cast(std::forward<T>(src), policy, parent);
     }
 };
@@ -408,7 +407,7 @@ struct variant_caster<V<Ts...>> {
     PYBIND11_TYPE_CASTER(Type,
                          const_name("Union[") + detail::concat(make_caster<Ts>::name...)
                              + const_name("]"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 #if defined(PYBIND11_HAS_VARIANT)
diff --git a/include/pybind11/stl/filesystem.h b/include/pybind11/stl/filesystem.h
index c5ac3faab..fff90cf36 100644
--- a/include/pybind11/stl/filesystem.h
+++ b/include/pybind11/stl/filesystem.h
@@ -99,7 +99,7 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(T, const_name("os.PathLike"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 };
 
 #endif // PYBIND11_HAS_FILESYSTEM || defined(PYBIND11_HAS_EXPERIMENTAL_FILESYSTEM)
diff --git a/tests/pybind11_tests.h b/tests/pybind11_tests.h
index 7ddd6c837..5ed373d6f 100644
--- a/tests/pybind11_tests.h
+++ b/tests/pybind11_tests.h
@@ -61,7 +61,7 @@ template <>
 class type_caster<RValueCaster> {
 public:
     PYBIND11_TYPE_CASTER(RValueCaster, const_name("RValueCaster"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     static handle cast(RValueCaster &&, return_value_policy, handle) {
         return py::str("rvalue").release();
     }
diff --git a/tests/test_builtin_casters.cpp b/tests/test_builtin_casters.cpp
index b063599f1..156880c1f 100644
--- a/tests/test_builtin_casters.cpp
+++ b/tests/test_builtin_casters.cpp
@@ -28,7 +28,7 @@ template <>
 class type_caster<ConstRefCasted> {
 public:
     static constexpr auto name = const_name<ConstRefCasted>();
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     // Input is unimportant, a new value will always be constructed based on the
     // cast operator.
diff --git a/tests/test_copy_move.cpp b/tests/test_copy_move.cpp
index 5cd9d8550..4c6ac2c74 100644
--- a/tests/test_copy_move.cpp
+++ b/tests/test_copy_move.cpp
@@ -106,7 +106,7 @@ PYBIND11_NAMESPACE_BEGIN(detail)
 template <>
 struct type_caster<MoveOnlyInt> {
     PYBIND11_TYPE_CASTER(MoveOnlyInt, const_name("MoveOnlyInt"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     bool load(handle src, bool) {
         value = MoveOnlyInt(src.cast<int>());
         return true;
@@ -119,7 +119,7 @@ struct type_caster<MoveOnlyInt> {
 template <>
 struct type_caster<MoveOrCopyInt> {
     PYBIND11_TYPE_CASTER(MoveOrCopyInt, const_name("MoveOrCopyInt"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     bool load(handle src, bool) {
         value = MoveOrCopyInt(src.cast<int>());
         return true;
@@ -136,7 +136,7 @@ protected:
 
 public:
     static constexpr auto name = const_name("CopyOnlyInt");
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     bool load(handle src, bool) {
         value = CopyOnlyInt(src.cast<int>());
         return true;
diff --git a/tests/test_custom_type_casters.cpp b/tests/test_custom_type_casters.cpp
index 911b30c35..8a3b32ebc 100644
--- a/tests/test_custom_type_casters.cpp
+++ b/tests/test_custom_type_casters.cpp
@@ -32,7 +32,7 @@ public:
 #else
     PYBIND11_TYPE_CASTER(ArgInspector1, const_name("ArgInspector1"));
 #endif
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     bool load(handle src, bool convert) {
         value.arg = "loading ArgInspector1 argument " + std::string(convert ? "WITH" : "WITHOUT")
@@ -50,7 +50,7 @@ template <>
 struct type_caster<ArgInspector2> {
 public:
     PYBIND11_TYPE_CASTER(ArgInspector2, const_name("ArgInspector2"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     bool load(handle src, bool convert) {
         value.arg = "loading ArgInspector2 argument " + std::string(convert ? "WITH" : "WITHOUT")
@@ -68,7 +68,7 @@ template <>
 struct type_caster<ArgAlwaysConverts> {
 public:
     PYBIND11_TYPE_CASTER(ArgAlwaysConverts, const_name("ArgAlwaysConverts"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
 
     bool load(handle, bool convert) { return convert; }
 
@@ -100,7 +100,7 @@ namespace detail {
 template <>
 struct type_caster<DestructionTester> {
     PYBIND11_TYPE_CASTER(DestructionTester, const_name("DestructionTester"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     bool load(handle, bool) { return true; }
 
     static handle cast(const DestructionTester &, return_value_policy, handle) {
@@ -123,7 +123,7 @@ namespace py_ = ::pybind11;
 // don't have any symbol collision when using macro mixin.
 struct my_caster {
     PYBIND11_TYPE_CASTER(MyType, py_::detail::const_name("MyType"));
-    static constexpr std::uint64_t universally_unique_identifier = 1655073597;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1655073597)
     bool load(py_::handle, bool) { return true; }
 
     static py_::handle cast(const MyType &, py_::return_value_policy, py_::handle) {
diff --git a/tests/test_odr_guard_1.cpp b/tests/test_odr_guard_1.cpp
index fb0703e14..bb55eec32 100644
--- a/tests/test_odr_guard_1.cpp
+++ b/tests/test_odr_guard_1.cpp
@@ -8,7 +8,7 @@ struct type_mrc {
 
 struct minimal_real_caster {
     static constexpr auto name = py::detail::const_name<type_mrc>();
-    static constexpr std::uint64_t universally_unique_identifier = 1000;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(1000)
 
     static py::handle
     cast(type_mrc const &src, py::return_value_policy /*policy*/, py::handle /*parent*/) {
diff --git a/tests/test_odr_guard_2.cpp b/tests/test_odr_guard_2.cpp
index 3fedb08ce..c67d99a5e 100644
--- a/tests/test_odr_guard_2.cpp
+++ b/tests/test_odr_guard_2.cpp
@@ -8,7 +8,7 @@ struct type_mrc {
 
 struct minimal_real_caster {
     static constexpr auto name = py::detail::const_name<type_mrc>();
-    static constexpr std::uint64_t universally_unique_identifier = 2000;
+    PYBIND11_TYPE_CASTER_UNIQUE_IDENTIFIER(2000)
 
     static py::handle
     cast(type_mrc const &src, py::return_value_policy /*policy*/, py::handle /*parent*/) {