diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
index 3ffb7051bfd1..0adac659123b 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
@@ -19,7 +19,8 @@ int main()
 {
     typedef std::negate<int> F;
     const F f = F();
-    static_assert((std::is_base_of<std::unary_function<int, int>, F>::value), "");
+    static_assert((std::is_same<F::argument_type, int>::value), "" );
+    static_assert((std::is_same<F::result_type, int>::value), "" );
     assert(f(36) == -36);
 #if _LIBCPP_STD_VER > 11
     typedef std::negate<> F2;
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
index 82efcbc29faa..48800a366a81 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
@@ -20,7 +20,8 @@ int main()
 #if _LIBCPP_STD_VER > 11
     typedef std::bit_not<int> F;
     const F f = F();
-    static_assert((std::is_base_of<std::unary_function<int, int>, F>::value), "");
+    static_assert((std::is_same<F::argument_type, int>::value), "" );
+    static_assert((std::is_same<F::result_type, int>::value), "" );
     assert((f(0xEA95) & 0xFFFF ) == 0x156A);
     assert((f(0x58D3) & 0xFFFF ) == 0xA72C);
     assert((f(0)      & 0xFFFF ) == 0xFFFF);
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
index 12b3543c5c6d..8484625a727c 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
@@ -19,7 +19,8 @@ int main()
 {
     typedef std::logical_not<int> F;
     const F f = F();
-    static_assert((std::is_base_of<std::unary_function<int, bool>, F>::value), "");
+    static_assert((std::is_same<F::argument_type, int>::value), "" );
+    static_assert((std::is_same<F::result_type, bool>::value), "" );
     assert(!f(36));
     assert(f(0));
 #if _LIBCPP_STD_VER > 11
diff --git a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
index 2aa4f0ab4480..e2498a3b52e2 100644
--- a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
@@ -19,7 +19,8 @@ int main()
 {
     typedef std::unary_negate<std::logical_not<int> > F;
     const F f = F(std::logical_not<int>());
-    static_assert((std::is_base_of<std::unary_function<int, bool>, F>::value), "");
+    static_assert((std::is_same<F::argument_type, int>::value), "" );
+    static_assert((std::is_same<F::result_type, bool>::value), "" );
     assert(f(36));
     assert(!f(0));
 }