diff --git a/src/core_test/cases/cases_helper.h b/src/core_test/cases/cases_helper.h
index a525c8c..d50ee78 100644
--- a/src/core_test/cases/cases_helper.h
+++ b/src/core_test/cases/cases_helper.h
@@ -31,8 +31,8 @@ protected:
 };
 
 /// Forcibly modify private variables to reset state.
-FORCIBLY_ACCESS(AllCases, available_, bool)
-FORCIBLY_ACCESS(BasicRanges, available_, bool)
+FORCE_ACCESS_VAR(AllCases, bool, available_)
+FORCE_ACCESS_VAR(BasicRanges, bool, available_)
 
 /// Test fixture macro with custom test suite name.
 #define TEST_FF(test_suite_name, test_name)                        \
diff --git a/src/core_test/codec/short_code.cc b/src/core_test/codec/short_code.cc
index 03e648d..fd2f1a6 100644
--- a/src/core_test/codec/short_code.cc
+++ b/src/core_test/codec/short_code.cc
@@ -21,17 +21,17 @@ using klotski::codec::SHORT_CODE_LIMIT;
 static const auto TEST_THREAD_NUM = 256;
 
 /// Forcibly modify private variables to reset state.
-//FORCIBLY_ACCESS(AllCases, available_, bool)
-//FORCIBLY_ACCESS(BasicRanges, available_, bool)
+FORCE_ACCESS_VAR(AllCases, bool, available_)
+FORCE_ACCESS_VAR(BasicRanges, bool, available_)
 
 /// Reset basic ranges build state, note it is thread-unsafe.
 void basic_ranges_reset() {
-//    exposer::BasicRanges_available_(BasicRanges::instance()) = false;
+    exposer::BasicRanges_available_(BasicRanges::instance()) = false;
 }
 
 /// Reset all cases build state, note it is thread-unsafe.
 void all_cases_reset() {
-//    exposer::AllCases_available_(AllCases::instance()) = false;
+    exposer::AllCases_available_(AllCases::instance()) = false;
 }
 
 TEST(ShortCode, limit) {
diff --git a/src/core_test/ffi/all_cases.cc b/src/core_test/ffi/all_cases.cc
index 81b5a3d..30921b1 100644
--- a/src/core_test/ffi/all_cases.cc
+++ b/src/core_test/ffi/all_cases.cc
@@ -16,37 +16,17 @@ using klotski::cases::ALL_CASES_NUM;
 static constexpr std::string_view ALL_CASES_MD5 = "3888e9fab8d3cbb50908b12b147cfb23";
 
 /// Forcibly modify private variables to reset state.
-//FORCIBLY_ACCESS(AllCases, available_, bool)
-//FORCIBLY_ACCESS(BasicRanges, available_, bool)
-
-FORCE_ACCESS_VAR(BasicRanges, available_, bool, Helper_1);
-FORCE_ACCESS_VAR(AllCases, available_, bool, Helper_2);
-
-//namespace exposer {
-//
-//struct Helper_1 {};
-//
-//template struct Exposer<bool (BasicRanges::*), &BasicRanges::available_, Helper_1>;
-//
-////template<>
-//constexpr bool BasicRanges::* fetch(Helper_1);
-//
-//bool& Demo_val(BasicRanges &c) {
-//    return c.*fetch(Helper_1{});
-//}
-//
-//}
+FORCE_ACCESS_VAR(AllCases, bool, available_)
+FORCE_ACCESS_VAR(BasicRanges, bool, available_)
 
 /// Reset basic ranges build state, note it is thread-unsafe.
 void basic_ranges_reset() {
     exposer::BasicRanges_available_(BasicRanges::instance()) = false;
-//    exposer::BasicRanges_available_(BasicRanges::instance()) = false;
 }
 
 /// Reset all cases build state, note it is thread-unsafe.
 void all_cases_reset() {
     exposer::AllCases_available_(AllCases::instance()) = false;
-//    exposer::AllCases_available_(AllCases::instance()) = false;
 }
 
 TEST(AllCases, all_cases_prebuild) {
diff --git a/src/core_test/utility/exposer.h b/src/core_test/utility/exposer.h
index 0923269..f959df2 100644
--- a/src/core_test/utility/exposer.h
+++ b/src/core_test/utility/exposer.h
@@ -6,52 +6,34 @@
 
 namespace exposer {
 
-// REF: http://bloglitb.blogspot.com/2010/07/access-to-private-members-thats-easy.html
-
-//template <typename T>
-//struct Exposer {
-//    static T ptr;
-//};
-//
-//template <typename T>
-//T Exposer<T>::ptr;
-//
-//template <typename T, T Ptr>
-//struct ExposerImpl {
-//    static struct Factory {
-//        Factory() { Exposer<T>::ptr = Ptr; }
-//    } factory;
-//};
-//
-//template <typename T, T Ptr>
-//typename ExposerImpl<T, Ptr>::Factory ExposerImpl<T, Ptr>::factory;
-
-//template <typename T>
-//constexpr T fetch();
-
-//template <typename T, T Val, int Flag>
-template <typename T, T Val, typename Unique>
+template <typename T, T Val, typename Tag>
 struct Exposer {
-//    constexpr friend T fetch<>() { return Val; }
-    constexpr friend T fetch(Unique) { return Val; }
+    constexpr friend T fetch(Tag) { return Val; }
 };
 
 } // namespace exposer
 
-#define FORCIBLY_ACCESS(Class, Member, Type)                                   \
-    namespace exposer {                                                        \
-        template struct ExposerImpl<decltype(&Class::Member), &Class::Member>; \
-        inline auto& Class##_##Member(Class &T) {                              \
-            return T.*exposer::Exposer<Type Class::*>::ptr;                    \
-        }                                                                      \
-    }
+#define COMBINE_IMPL(x, y) x##y
+
+#define COMBINE(x, y) COMBINE_IMPL(x, y)
+
+#define UNIQUE_TAG COMBINE(Tag, __COUNTER__)
 
-#define FORCE_ACCESS_VAR(Class, Member, Type, Unique) \
+#define FORCE_ACCESS_VAR_IMPL(Class, Type, Member, Tag) \
     namespace exposer { \
-        struct Unique {}; \
-        template struct Exposer<Type (Class::*), &Class::Member, Unique>; \
-        constexpr Type Class::* fetch(Unique); \
-        Type& Class##_##Member(Class &T) { \
-            return T.*fetch(Unique{}); \
+        struct Tag {}; \
+        template struct Exposer<Type(Class::*), &Class::Member, Tag>; \
+        constexpr Type Class::* fetch(Tag); \
+        constexpr Type& Class##_##Member(Class &c) { \
+            return c.*fetch(Tag{}); \
+        } \
+        constexpr const Type& Class##_##Member(const Class &c) { \
+            return c.*fetch(Tag{}); \
+        } \
+        constexpr Type Class##_##Member(Class &&c) { \
+            return c.*fetch(Tag{}); \
         } \
     }
+
+#define FORCE_ACCESS_VAR(Class, Type, Member) \
+    FORCE_ACCESS_VAR_IMPL(Class, Type, Member, UNIQUE_TAG)