1 files changed, 12 insertions, 3 deletions
diff --git a/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp b/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
index 27af66e0670b..00d29c0de0e3 100644
--- a/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.ops/string_substr/substr.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 
 template <class S>
-void
+TEST_CONSTEXPR_CXX20 void
 test(const S& s, typename S::size_type pos, typename S::size_type n)
 {
     if (pos <= s.size())
@@ -47,8 +47,7 @@ test(const S& s, typename S::size_type pos, typename S::size_type n)
 #endif
 }
 
-int main(int, char**)
-{
+bool test() {
     {
     typedef std::string S;
     test(S(""), 0, 0);
@@ -174,5 +173,15 @@ int main(int, char**)
     }
 #endif
 
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
+#endif
+
   return 0;
 }