diff --git a/libcxx/include/string b/libcxx/include/string
index 4f05e211919f3..67c4c537eb3b5 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -3434,8 +3434,8 @@ inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void basic_string<_CharT, _Traits, _Allocat
 
   if (__fits_in_sso(__target_capacity)) {
     __annotation_guard __g(*this);
-    traits_type::copy(std::__to_address(__get_short_pointer()), std::__to_address(__ptr), __size + 1);
     __set_short_size(__size);
+    traits_type::copy(std::__to_address(__get_short_pointer()), std::__to_address(__ptr), __size + 1);
     __alloc_traits::deallocate(__alloc_, __ptr, __cap);
     return;
   }
diff --git a/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp b/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
index 9ca7825a4ba92..a3b16c8da16cb 100644
--- a/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.capacity/shrink_to_fit.pass.cpp
@@ -19,7 +19,7 @@
 #include "test_macros.h"
 
 template <class S>
-TEST_CONSTEXPR_CXX20 void test(S s) {
+TEST_CONSTEXPR_CXX20 void test(S& s) {
   typename S::size_type old_cap = s.capacity();
   S s0                          = s;
   s.shrink_to_fit();