diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
index f644f2870753d3..5fe15fbf23e245 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap.pass.cpp
@@ -21,7 +21,7 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(S s1, S s2)
 {
     S s1_ = s1;
@@ -33,9 +33,8 @@ test(S s1, S s2)
     assert(s2 == s1_);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""));
     test(S(""), S("12345"));
@@ -53,9 +52,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("12345"));
     test(S("abcdefghijklmnopqrst"), S("1234567890"));
     test(S("abcdefghijklmnopqrst"), S("12345678901234567890"));
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""));
     test(S(""), S("12345"));
@@ -73,7 +72,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("12345"));
     test(S("abcdefghijklmnopqrst"), S("1234567890"));
     test(S("abcdefghijklmnopqrst"), S("12345678901234567890"));
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
index 3de398264d4dcb..b301a5055bb727 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs != rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), false);
     test("", S("abcde"), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), false);
     test("", S("abcde"), true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
index 220bde69caf004..db79165d568d2c 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs != rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", false);
     test(S(""), "abcde", true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", false);
     test(S(""), "abcde", true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
index 51d9f60629cbec..c5007fd15a58ed 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs != rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), true);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
index 80ef8daf2c039c..23990f1fb77508 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs != rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string SV;
     test(S(""), SV(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
index bd81bb1667065a..1cb88d1786625b 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op!=/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs != rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
index 9ab3c0611971db..f9f8cd95fb9843 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/char_string.pass.cpp
@@ -24,18 +24,18 @@
 #include "min_allocator.h"
 
 template <class S>
-void test0(typename S::value_type lhs, const S& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test0(typename S::value_type lhs, const S& rhs, const S& x) {
   assert(lhs + rhs == x);
 }
 
 #if TEST_STD_VER >= 11
 template <class S>
-void test1(typename S::value_type lhs, S&& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test1(typename S::value_type lhs, S&& rhs, const S& x) {
   assert(lhs + move(rhs) == x);
 }
 #endif
 
-int main(int, char**) {
+bool test() {
   {
     typedef std::string S;
     test0('a', S(""), S("a"));
@@ -67,5 +67,14 @@ int main(int, char**) {
   }
 #endif
 
+  return true;
+}
+
+int main(int, char**) {
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
index cf13fbb51d6e17..89fadc2227e292 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/pointer_string.pass.cpp
@@ -24,18 +24,18 @@
 #include "min_allocator.h"
 
 template <class S>
-void test0(const typename S::value_type* lhs, const S& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test0(const typename S::value_type* lhs, const S& rhs, const S& x) {
   assert(lhs + rhs == x);
 }
 
 #if TEST_STD_VER >= 11
 template <class S>
-void test1(const typename S::value_type* lhs, S&& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test1(const typename S::value_type* lhs, S&& rhs, const S& x) {
   assert(lhs + move(rhs) == x);
 }
 #endif
 
-int main(int, char**) {
+bool test() {
   {
     typedef std::string S;
     test0("", S(""), S(""));
@@ -128,5 +128,14 @@ int main(int, char**) {
   }
 #endif
 
+  return true;
+}
+
+int main(int, char**) {
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
index 32411144db276e..ee2a2395396871 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_char.pass.cpp
@@ -24,18 +24,18 @@
 #include "min_allocator.h"
 
 template <class S>
-void test0(const S& lhs, typename S::value_type rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test0(const S& lhs, typename S::value_type rhs, const S& x) {
   assert(lhs + rhs == x);
 }
 
 #if TEST_STD_VER >= 11
 template <class S>
-void test1(S&& lhs, typename S::value_type rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test1(S&& lhs, typename S::value_type rhs, const S& x) {
   assert(move(lhs) + rhs == x);
 }
 #endif
 
-int main(int, char**) {
+bool test() {
   {
     typedef std::string S;
     test0(S(""), '1', S("1"));
@@ -67,5 +67,14 @@ int main(int, char**) {
   }
 #endif
 
+  return true;
+}
+
+int main(int, char**) {
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
index 4fec8482966233..bdcc464e5a8e94 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_pointer.pass.cpp
@@ -24,18 +24,18 @@
 #include "min_allocator.h"
 
 template <class S>
-void test0(const S& lhs, const typename S::value_type* rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test0(const S& lhs, const typename S::value_type* rhs, const S& x) {
   assert(lhs + rhs == x);
 }
 
 #if TEST_STD_VER >= 11
 template <class S>
-void test1(S&& lhs, const typename S::value_type* rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test1(S&& lhs, const typename S::value_type* rhs, const S& x) {
   assert(move(lhs) + rhs == x);
 }
 #endif
 
-int main(int, char**) {
+bool test() {
   {
     typedef std::string S;
     test0(S(""), "", S(""));
@@ -127,5 +127,14 @@ int main(int, char**) {
   }
 #endif
 
+  return true;
+}
+
+int main(int, char**) {
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
index 00aaf5cc092170..3c349ed96f74c5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+/string_string.pass.cpp
@@ -36,29 +36,28 @@
 #include "min_allocator.h"
 
 template <class S>
-void test0(const S& lhs, const S& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test0(const S& lhs, const S& rhs, const S& x) {
   assert(lhs + rhs == x);
 }
 
 #if TEST_STD_VER >= 11
 template <class S>
-void test1(S&& lhs, const S& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test1(S&& lhs, const S& rhs, const S& x) {
   assert(move(lhs) + rhs == x);
 }
 
 template <class S>
-void test2(const S& lhs, S&& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test2(const S& lhs, S&& rhs, const S& x) {
   assert(lhs + move(rhs) == x);
 }
 
 template <class S>
-void test3(S&& lhs, S&& rhs, const S& x) {
+TEST_CONSTEXPR_CXX20 void test3(S&& lhs, S&& rhs, const S& x) {
   assert(move(lhs) + move(rhs) == x);
 }
-
 #endif
 
-int main(int, char**) {
+bool test() {
   {
     typedef std::string S;
     test0(S(""), S(""), S(""));
@@ -246,5 +245,14 @@ int main(int, char**) {
   }
 #endif // TEST_STD_VER >= 11
 
+  return true;
+}
+
+int main(int, char**) {
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
index 0efd829ee0d17f..1b9153168fd82f 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs == rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), true);
     test("", S("abcde"), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), true);
     test("", S("abcde"), false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
index ae0d3e88d5faaf..9e6ddcf93d54d9 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs == rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", true);
     test(S(""), "abcde", false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", true);
     test(S(""), "abcde", false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
index 387c0016dc15b1..aafabdec68a025 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs == rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), false);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
index a525c752d6cd15..be393ab5c4c0e5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs == rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(""), SV(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string     <char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
index 793fa2388b274f..36cd9e478b61b1 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_operator==/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs == rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
index 2e96167b41997e..781aafca5d493a 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs > rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), false);
     test("", S("abcde"), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), false);
     test("", S("abcde"), false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
index 57c979d0caafa1..c1e5b5b18e3cbc 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs > rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", false);
     test(S(""), "abcde", false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", false);
     test(S(""), "abcde", false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
index cc6f331756f962..863ecec14580ed 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs > rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), false);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
index 7f6ad7d3bd2107..2220c11571b4a5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs > rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(""), SV(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string     <char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
index b96ee17aa2e606..18bec19a8df74a 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs > rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string     <char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
index 9082f36c94882e..4ac1ddd9feccaf 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs >= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), true);
     test("", S("abcde"), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), true);
     test("", S("abcde"), false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), true);
     test("abcdefghijklmnopqrst", S("abcdefghij"), true);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
index 72ed73aa2d8c33..2d64d40a4a39b1 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs >= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", true);
     test(S(""), "abcde", false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", true);
     test(S(""), "abcde", false);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", true);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
index 604698a8d0c104..252a1f1325b56d 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs >= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), false);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
index 131f83ea446484..f7fcc250c183db 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs >= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(""), SV(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), true);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
index 45c0ed11eed023..e0c62c66fc6f1c 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_opgt=/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs >= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), true);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
index 5e96bf37b34501..02f725c09a0892 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs < rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), false);
     test("", S("abcde"), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), false);
     test("", S("abcde"), true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
index f01b69e620b3fd..6909cf884db9b3 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs < rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", false);
     test(S(""), "abcde", true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", false);
     test(S(""), "abcde", true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
index b6a61f7034f6cc..0cd4f64c812737 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs < rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), true);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), false);
     test(S(""), S("abcde"), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
index fa81ae88fbeed3..470ee16bec1e57 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs < rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(""), SV(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
index 54f8015442a02e..b0baab5085a2a5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs < rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), false);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), false);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), false);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
index 5c43125974e959..67c090d22a83b6 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/pointer_string.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const typename S::value_type* lhs, const S& rhs, bool x)
 {
     assert((lhs <= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test("", S(""), true);
     test("", S("abcde"), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test("", S(""), true);
     test("", S("abcde"), true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test("abcdefghijklmnopqrst", S("abcde"), false);
     test("abcdefghijklmnopqrst", S("abcdefghij"), false);
     test("abcdefghijklmnopqrst", S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
index 3b1dc2cb8a165c..3a6ba9e0871bb5 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_pointer.pass.cpp
@@ -18,15 +18,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const typename S::value_type* rhs, bool x)
 {
     assert((lhs <= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), "", true);
     test(S(""), "abcde", true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), "", true);
     test(S(""), "abcde", true);
@@ -64,7 +63,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), "abcde", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghij", false);
     test(S("abcdefghijklmnopqrst"), "abcdefghijklmnopqrst", true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
index 219ed5101b298a..ddec31bd335553 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string.pass.cpp
@@ -19,15 +19,14 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, const S& rhs, bool x)
 {
     assert((lhs <= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), true);
@@ -45,9 +44,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     test(S(""), S(""), true);
     test(S(""), S("abcde"), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), S("abcde"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
index 52806ae60bdd63..dfd8877a62bd2f 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_string_view.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& lhs, SV rhs, bool x)
 {
     assert((lhs <= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(""), SV(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(S(""), SV(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(S("abcdefghijklmnopqrst"), SV("abcde"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghij"), false);
     test(S("abcdefghijklmnopqrst"), SV("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
index 961fc0e5b87a2b..527a45a199059d 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string_oplt=/string_view_string.pass.cpp
@@ -17,15 +17,14 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(SV lhs, const S& rhs, bool x)
 {
     assert((lhs <= rhs) == x);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(SV(""), S(""), true);
@@ -44,9 +43,9 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char>> SV;
     test(SV(""), S(""), true);
@@ -65,7 +64,17 @@ int main(int, char**)
     test(SV("abcdefghijklmnopqrst"), S("abcde"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghij"), false);
     test(SV("abcdefghijklmnopqrst"), S("abcdefghijklmnopqrst"), true);
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;