diff --git a/libcxx/docs/Cxx2aStatusIssuesStatus.csv b/libcxx/docs/Cxx2aStatusIssuesStatus.csv
--- a/libcxx/docs/Cxx2aStatusIssuesStatus.csv
+++ b/libcxx/docs/Cxx2aStatusIssuesStatus.csv
@@ -168,7 +168,7 @@
 "`3230 <https://wg21.link/LWG3230>`__","Format specifier ``%y/%Y``\  is missing locale alternative versions","Belfast","",""
 "`3232 <https://wg21.link/LWG3232>`__","Inconsistency in ``zoned_time``\  deduction guides","Belfast","",""
 "`3222 <https://wg21.link/LWG3222>`__","P0574R1 introduced preconditions on non-existent parameters","Belfast","",""
-"`3221 <https://wg21.link/LWG3221>`__","Result of ``year_month``\  arithmetic with ``months``\  is ambiguous","Belfast","",""
+"`3221 <https://wg21.link/LWG3221>`__","Result of ``year_month``\  arithmetic with ``months``\  is ambiguous","Belfast","|Complete|","8.0"
 "`3235 <https://wg21.link/LWG3235>`__","``parse``\  manipulator without abbreviation is not callable","Belfast","",""
 "`3246 <https://wg21.link/LWG3246>`__","What are the constraints on the template parameter of ``basic_format_arg``\ ?","Belfast","",""
 "`3253 <https://wg21.link/LWG3253>`__","``basic_syncbuf::basic_syncbuf()``\  should not be explicit","Belfast","",""
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
@@ -17,91 +17,91 @@
 // Returns: ym + dy.
 //
 // constexpr year_month operator+(const year_month& ym, const months& dm) noexcept;
-// Returns: A year_month value z such that z - ym == dm.
+// Returns: A year_month value z such that z.ok() && z - ym == dm is true.
 // Complexity: O(1) with respect to the value of dm.
 //
 // constexpr year_month operator+(const months& dm, const year_month& ym) noexcept;
 // Returns: ym + dm.
 
-
-
 #include <chrono>
 #include <type_traits>
 #include <cassert>
 
 #include "test_macros.h"
 
-constexpr bool testConstexprYears(std::chrono::year_month ym)
-{
-    std::chrono::years offset{23};
-    if (static_cast<int>((ym         ).year()) !=  1) return false;
-    if (static_cast<int>((ym + offset).year()) != 24) return false;
-    if (static_cast<int>((offset + ym).year()) != 24) return false;
-    return true;
+using year = std::chrono::year;
+using years = std::chrono::years;
+using month = std::chrono::month;
+using months = std::chrono::months;
+using year_month = std::chrono::year_month;
+
+// year_month + years
+constexpr bool test_ym_plus_y() {
+  ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<years>());
+  ASSERT_NOEXCEPT(std::declval<years>() + std::declval<year_month>());
+
+  ASSERT_SAME_TYPE(
+      year_month, decltype(std::declval<year_month>() + std::declval<years>()));
+  ASSERT_SAME_TYPE(
+      year_month, decltype(std::declval<years>() + std::declval<year_month>()));
+
+  year_month ym{year{1234}, std::chrono::January};
+  for (int i = 0; i <= 10; ++i) {
+    year_month ym1 = ym + years{i};
+    year_month ym2 = years{i} + ym;
+    assert(static_cast<int>(ym1.year()) == i + 1234);
+    assert(static_cast<int>(ym2.year()) == i + 1234);
+    assert(ym1.month() == std::chrono::January);
+    assert(ym2.month() == std::chrono::January);
+    assert(ym1 == ym2);
+  }
+
+  return true;
 }
 
-
-constexpr bool testConstexprMonths(std::chrono::year_month ym)
-{
-    std::chrono::months offset{6};
-    if (static_cast<unsigned>((ym         ).month()) !=  1) return false;
-    if (static_cast<unsigned>((ym + offset).month()) !=  7) return false;
-    if (static_cast<unsigned>((offset + ym).month()) !=  7) return false;
-    return true;
+// year_month + months
+constexpr bool test_ym_plus_m() {
+  ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<months>());
+  ASSERT_NOEXCEPT(std::declval<months>() + std::declval<year_month>());
+
+  ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() +
+                                        std::declval<months>()));
+  ASSERT_SAME_TYPE(year_month, decltype(std::declval<months>() +
+                                        std::declval<year_month>()));
+
+  year_month ym{year{1234}, std::chrono::January};
+  for (int i = 0; i <= 11; ++i) {
+    year_month ym1 = ym + months{i};
+    year_month ym2 = months{i} + ym;
+    assert(static_cast<int>(ym1.year()) == 1234);
+    assert(static_cast<int>(ym2.year()) == 1234);
+    assert(ym1.month() == month(1 + i));
+    assert(ym2.month() == month(1 + i));
+    assert(ym1 == ym2);
+  }
+
+  for (int i = 12; i < 23; ++i) {
+    year_month ym1 = ym + months{i};
+    year_month ym2 = months{i} + ym;
+    assert(static_cast<int>(ym1.year()) == 1235);
+    assert(static_cast<int>(ym2.year()) == 1235);
+    assert(ym1.month() == month(1 + i % 12));
+    assert(ym2.month() == month(1 + i % 12));
+    assert(ym1 == ym2);
+  }
+
+  return true;
 }
 
+constexpr bool test() {
+  test_ym_plus_y();
+  test_ym_plus_m();
+  return true;
+}
 
-int main(int, char**)
-{
-    using year       = std::chrono::year;
-    using years      = std::chrono::years;
-    using month      = std::chrono::month;
-    using months     = std::chrono::months;
-    using year_month = std::chrono::year_month;
-
-    {   // year_month + years
-    ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<years>());
-    ASSERT_NOEXCEPT(std::declval<years>() + std::declval<year_month>());
-
-    ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() + std::declval<years>()));
-    ASSERT_SAME_TYPE(year_month, decltype(std::declval<years>() + std::declval<year_month>()));
-
-    static_assert(testConstexprYears (year_month{year{1}, month{1}}), "");
-
-    year_month ym{year{1234}, std::chrono::January};
-    for (int i = 0; i <= 10; ++i)
-    {
-        year_month ym1 = ym + years{i};
-        year_month ym2 = years{i} + ym;
-        assert(static_cast<int>(ym1.year()) == i + 1234);
-        assert(static_cast<int>(ym2.year()) == i + 1234);
-        assert(ym1.month() == std::chrono::January);
-        assert(ym2.month() == std::chrono::January);
-        assert(ym1 == ym2);
-    }
-    }
-
-    {   // year_month + months
-    ASSERT_NOEXCEPT(std::declval<year_month>() + std::declval<months>());
-    ASSERT_NOEXCEPT(std::declval<months>() + std::declval<year_month>());
-
-    ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() + std::declval<months>()));
-    ASSERT_SAME_TYPE(year_month, decltype(std::declval<months>() + std::declval<year_month>()));
-
-    static_assert(testConstexprMonths(year_month{year{1}, month{1}}), "");
-
-    year_month ym{year{1234}, std::chrono::January};
-    for (int i = 0; i <= 10; ++i)  // TODO test wrap-around
-    {
-        year_month ym1 = ym + months{i};
-        year_month ym2 = months{i} + ym;
-        assert(static_cast<int>(ym1.year()) == 1234);
-        assert(static_cast<int>(ym2.year()) == 1234);
-        assert(ym1.month() == month(1 + i));
-        assert(ym2.month() == month(1 + i));
-        assert(ym1 == ym2);
-    }
-    }
+int main(int, char**) {
+  test();
+  static_assert(test());
 
   return 0;
 }