diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 9f94f2902..1d38f3a47 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -95,7 +95,6 @@ private:
 public:
     bool load(handle src, bool convert) { return subcaster.load(src, convert); }
     static constexpr auto name = caster_t::name;
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
     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
@@ -110,13 +109,12 @@ public:
     explicit operator std::reference_wrapper<type>() { return cast_op<type &>(subcaster); }
 };
 
-#define PYBIND11_DETAIL_TYPE_CASTER_HEAD(type, py_name)                                           \
+#define PYBIND11_TYPE_CASTER(type, py_name)                                                       \
 protected:                                                                                        \
     type value;                                                                                   \
                                                                                                   \
 public:                                                                                           \
-    static constexpr auto name = py_name;
-#define PYBIND11_DETAIL_TYPE_CASTER_TAIL(type)                                                    \
+    static constexpr auto name = py_name;                                                         \
     template <typename T_,                                                                        \
               ::pybind11::detail::enable_if_t<                                                    \
                   std::is_same<type, ::pybind11::detail::remove_cv_t<T_>>::value,                 \
@@ -138,22 +136,6 @@ public:
     template <typename T_>                                                                        \
     using cast_op_type = ::pybind11::detail::movable_cast_op_type<T_>
 
-#ifdef PYBIND11_TYPE_CASTER_ODR_GUARD_ON
-
-#    define PYBIND11_TYPE_CASTER(type, py_name)                                                   \
-        PYBIND11_DETAIL_TYPE_CASTER_HEAD(type, py_name)                                           \
-        static constexpr auto source_file_line                                                    \
-            = ::pybind11::detail::tu_local_const_name(__FILE__ ":" PYBIND11_TOSTRING(__LINE__));  \
-        PYBIND11_DETAIL_TYPE_CASTER_TAIL(type)
-
-#else
-
-#    define PYBIND11_TYPE_CASTER(type, py_name)                                                   \
-        PYBIND11_DETAIL_TYPE_CASTER_HEAD(type, py_name)                                           \
-        PYBIND11_DETAIL_TYPE_CASTER_TAIL(type)
-
-#endif
-
 template <typename CharT>
 using is_std_char_type = any_of<std::is_same<CharT, char>, /* std::string */
 #if defined(PYBIND11_HAS_U8STRING)
@@ -346,7 +328,6 @@ public:
     using cast_op_type = void *&;
     explicit operator void *&() { return value; }
     static constexpr auto name = const_name("capsule");
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
 private:
     void *value = nullptr;
@@ -667,7 +648,6 @@ public:
     }
 
     static constexpr auto name = const_name(PYBIND11_STRING_NAME);
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
     template <typename _T>
     using cast_op_type = pybind11::detail::cast_op_type<_T>;
 };
@@ -712,7 +692,6 @@ public:
 
     static constexpr auto name
         = const_name("Tuple[") + concat(make_caster<Ts>::name...) + const_name("]");
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     template <typename T>
     using cast_op_type = type;
@@ -885,7 +864,6 @@ 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;
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 };
 
 #ifndef PYBIND11_USE_SMART_HOLDER_AS_DEFAULT
diff --git a/include/pybind11/detail/init.h b/include/pybind11/detail/init.h
index c95f5abb1..18adc40b1 100644
--- a/include/pybind11/detail/init.h
+++ b/include/pybind11/detail/init.h
@@ -27,7 +27,6 @@ public:
     using cast_op_type = value_and_holder &;
     explicit operator value_and_holder &() { return *value; }
     static constexpr auto name = const_name<value_and_holder>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
 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 95346cd08..52b37d591 100644
--- a/include/pybind11/detail/smart_holder_type_casters.h
+++ b/include/pybind11/detail/smart_holder_type_casters.h
@@ -616,7 +616,6 @@ 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>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     // static handle cast(T, ...)
     // is redundant (leads to ambiguous overloads).
@@ -778,7 +777,6 @@ 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>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     static handle cast(const std::shared_ptr<T> &src, return_value_policy policy, handle parent) {
         switch (policy) {
@@ -843,7 +841,6 @@ 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>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     static handle
     cast(const std::shared_ptr<T const> &src, return_value_policy policy, handle parent) {
@@ -864,7 +861,6 @@ 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>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     static handle cast(std::unique_ptr<T, D> &&src, return_value_policy policy, handle parent) {
         if (policy != return_value_policy::automatic
@@ -948,7 +944,6 @@ 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>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     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 556d7afbf..777fbb716 100644
--- a/include/pybind11/detail/type_caster_base.h
+++ b/include/pybind11/detail/type_caster_base.h
@@ -13,7 +13,6 @@
 #include "common.h"
 #include "descr.h"
 #include "internals.h"
-#include "type_caster_odr_guard.h"
 #include "typeid.h"
 
 #include <cstdint>
@@ -912,7 +911,6 @@ class type_caster_base : public type_caster_generic {
 
 public:
     static constexpr auto name = const_name<type>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     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/detail/type_caster_odr_guard.h b/include/pybind11/detail/type_caster_odr_guard.h
index 3ec839c87..4d36b3f0d 100644
--- a/include/pybind11/detail/type_caster_odr_guard.h
+++ b/include/pybind11/detail/type_caster_odr_guard.h
@@ -9,17 +9,14 @@
 // The type_caster ODR guard feature requires Translation-Unit-local entities
 // (https://en.cppreference.com/w/cpp/language/tu_local), a C++20 feature, but
 // almost all tested C++17 compilers support this feature already.
-// This highly correlates with the preconditions for PYBIND11_DETAIL_DESCR_SRC_LOC_ON.
+// The preconditions for PYBIND11_DETAIL_DESCR_SRC_LOC_ON happen to be a subset of
+// the preconditions for PYBIND11_TYPE_CASTER_ODR_GUARD_ON.
 #if !defined(PYBIND11_TYPE_CASTER_ODR_GUARD_ON) && !defined(PYBIND11_TYPE_CASTER_ODR_GUARD_OFF)   \
     && defined(PYBIND11_DETAIL_DESCR_SRC_LOC_ON)
 #    define PYBIND11_TYPE_CASTER_ODR_GUARD_ON
 #endif
 
-#ifndef PYBIND11_TYPE_CASTER_ODR_GUARD_ON
-
-#    define PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
-
-#else
+#ifdef PYBIND11_TYPE_CASTER_ODR_GUARD_ON
 
 #    if !defined(PYBIND11_CPP20) && defined(__GNUC__) && !defined(__clang__)
 #        pragma GCC diagnostic ignored "-Wsubobject-linkage"
@@ -66,28 +63,18 @@ inline std::string source_file_line_basename(const char *sfl) {
 #    endif
 
 inline void type_caster_odr_guard_impl(const std::type_info &intrinsic_type_info,
-                                       const char *source_file_line_from_macros,
                                        const src_loc &sloc,
                                        bool throw_disabled) {
     std::string source_file_line_from_sloc
         = std::string(sloc.file) + ':' + std::to_string(sloc.line);
-    // std::cout cannot be used here: static initialization could be incomplete.
 #    define PYBIND11_DETAIL_TYPE_CASTER_ODR_GUARD_IMPL_PRINTF_OFF
 #    ifdef PYBIND11_DETAIL_TYPE_CASTER_ODR_GUARD_IMPL_PRINTF_ON
+    // std::cout cannot be used here: static initialization could be incomplete.
     std::fprintf(stdout,
                  "\nTYPE_CASTER_ODR_GUARD_IMPL %s %s\n",
                  clean_type_id(intrinsic_type_info.name()).c_str(),
-                 source_file_line_from_macros);
-    std::fprintf(stdout,
-                 "%s %s %s\n",
-                 (source_file_line_from_sloc == source_file_line_from_macros
-                      ? "                 SLOC_SAME"
-                      : "                 SLOC_DIFF"),
-                 clean_type_id(intrinsic_type_info.name()).c_str(),
                  source_file_line_from_sloc.c_str());
     std::fflush(stdout);
-#    else
-    silence_unused_warnings(source_file_line_from_macros);
 #    endif
     auto ins = type_caster_odr_guard_registry().insert(
         {std::type_index(intrinsic_type_info), source_file_line_from_sloc});
@@ -112,66 +99,12 @@ inline void type_caster_odr_guard_impl(const std::type_info &intrinsic_type_info
 
 namespace {
 
-template <size_t N, typename... Ts>
-struct tu_local_descr {
-    char text[N + 1]{'\0'};
-    src_loc sloc;
-
-    explicit constexpr tu_local_descr(src_loc sloc = src_loc::here()) : sloc(sloc) {}
-    // NOLINTNEXTLINE(google-explicit-constructor)
-    constexpr tu_local_descr(char const (&s)[N + 1], src_loc sloc = src_loc::here())
-        : tu_local_descr(s, make_index_sequence<N>(), sloc) {}
-
-    template <size_t... Is>
-    constexpr tu_local_descr(char const (&s)[N + 1],
-                             index_sequence<Is...>,
-                             src_loc sloc = src_loc::here())
-        : text{s[Is]..., '\0'}, sloc(sloc) {}
-
-    template <typename... Chars>
-    // NOLINTNEXTLINE(google-explicit-constructor)
-    constexpr tu_local_descr(char c, Chars... cs, src_loc sloc = src_loc::here())
-        : text{c, static_cast<char>(cs)..., '\0'}, sloc(sloc) {}
-};
-
-template <size_t N>
-constexpr tu_local_descr<N - 1> tu_local_const_name(char const (&text)[N],
-                                                    src_loc sloc = src_loc::here()) {
-    return tu_local_descr<N - 1>(text, sloc);
-}
-constexpr tu_local_descr<0> tu_local_const_name(char const (&)[1],
-                                                src_loc sloc = src_loc::here()) {
-    return tu_local_descr<0>(sloc);
-}
-
 struct tu_local_no_data_always_false {
     explicit operator bool() const noexcept { return false; }
 };
 
 } // namespace
 
-#    ifndef PYBIND11_TYPE_CASTER_ODR_GUARD_STRICT
-#        define PYBIND11_TYPE_CASTER_ODR_GUARD_STRICT
-#    endif
-
-template <typename TypeCasterType, typename SFINAE = void>
-struct get_type_caster_source_file_line {
-#    ifdef PYBIND11_TYPE_CASTER_ODR_GUARD_STRICT
-    static_assert(TypeCasterType::source_file_line,
-                  "PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE is MISSING: Please add that macro to the "
-                  "TypeCasterType, or undefine PYBIND11_TYPE_CASTER_ODR_GUARD_STRICT");
-#    else
-    static constexpr auto source_file_line = tu_local_const_name("UNAVAILABLE");
-#    endif
-};
-
-template <typename TypeCasterType>
-struct get_type_caster_source_file_line<
-    TypeCasterType,
-    enable_if_t<std::is_class<decltype(TypeCasterType::source_file_line)>::value>> {
-    static constexpr auto source_file_line = TypeCasterType::source_file_line;
-};
-
 template <typename IntrinsicType, typename TypeCasterType>
 struct type_caster_odr_guard : TypeCasterType {
     static tu_local_no_data_always_false translation_unit_local;
@@ -194,19 +127,13 @@ template <typename IntrinsicType, typename TypeCasterType>
 tu_local_no_data_always_false
     type_caster_odr_guard<IntrinsicType, TypeCasterType>::translation_unit_local
     = []() {
-          type_caster_odr_guard_impl(
-              typeid(IntrinsicType),
-              get_type_caster_source_file_line<TypeCasterType>::source_file_line.text,
-              TypeCasterType::name.sloc,
-              PYBIND11_DETAIL_TYPE_CASTER_ODR_GUARD_IMPL_THROW_DISABLED);
+          type_caster_odr_guard_impl(typeid(IntrinsicType),
+                                     TypeCasterType::name.sloc,
+                                     PYBIND11_DETAIL_TYPE_CASTER_ODR_GUARD_IMPL_THROW_DISABLED);
           return tu_local_no_data_always_false();
       }();
 
 PYBIND11_NAMESPACE_END(detail)
 PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
 
-#    define PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE                                                 \
-        static constexpr auto source_file_line                                                    \
-            = ::pybind11::detail::tu_local_const_name(__FILE__ ":" PYBIND11_TOSTRING(__LINE__));
-
 #endif
diff --git a/include/pybind11/eigen.h b/include/pybind11/eigen.h
index 93eb6ee0a..beb50266e 100644
--- a/include/pybind11/eigen.h
+++ b/include/pybind11/eigen.h
@@ -392,7 +392,6 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     // NOLINTNEXTLINE(google-explicit-constructor)
     operator Type *() { return &value; }
@@ -437,7 +436,6 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     // 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 +623,6 @@ public:
     }
 
     static constexpr auto name = props::descriptor;
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     // 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
diff --git a/tests/test_builtin_casters.cpp b/tests/test_builtin_casters.cpp
index 654e7f7f1..9c0ec73f6 100644
--- a/tests/test_builtin_casters.cpp
+++ b/tests/test_builtin_casters.cpp
@@ -28,7 +28,6 @@ template <>
 class type_caster<ConstRefCasted> {
 public:
     static constexpr auto name = const_name<ConstRefCasted>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     // 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 82e9eec29..28c244564 100644
--- a/tests/test_copy_move.cpp
+++ b/tests/test_copy_move.cpp
@@ -134,7 +134,6 @@ protected:
 
 public:
     static constexpr auto name = const_name("CopyOnlyInt");
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
     bool load(handle src, bool) {
         value = CopyOnlyInt(src.cast<int>());
         return true;
diff --git a/tests/test_type_caster_odr_guard_1.cpp b/tests/test_type_caster_odr_guard_1.cpp
index 0851b0ce2..2deaf1754 100644
--- a/tests/test_type_caster_odr_guard_1.cpp
+++ b/tests/test_type_caster_odr_guard_1.cpp
@@ -15,7 +15,6 @@ struct type_mrc {
 
 struct minimal_real_caster {
     static constexpr auto name = py::detail::const_name<type_mrc>();
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
 
     static py::handle
     cast(type_mrc const &src, py::return_value_policy /*policy*/, py::handle /*parent*/) {
diff --git a/tests/test_type_caster_odr_guard_2.cpp b/tests/test_type_caster_odr_guard_2.cpp
index ae4631a99..e255f2a23 100644
--- a/tests/test_type_caster_odr_guard_2.cpp
+++ b/tests/test_type_caster_odr_guard_2.cpp
@@ -15,9 +15,6 @@ struct type_mrc {
 
 struct minimal_real_caster {
     static constexpr auto name = py::detail::const_name<type_mrc>();
-#ifdef PYBIND11_TYPE_CASTER_ODR_GUARD_STRICT
-    PYBIND11_TYPE_CASTER_SOURCE_FILE_LINE
-#endif
 
     static py::handle
     cast(type_mrc const &src, py::return_value_policy /*policy*/, py::handle /*parent*/) {