diff --git a/libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp b/libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp
index 136910b90c909..c47fb188c865c 100644
--- a/libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp
@@ -27,10 +27,10 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 #include <queue>
 #include <stack>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -44,7 +44,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class StringViewT>
diff --git a/libcxx/test/std/containers/sequences/vector.bool/vector.bool.fmt/parse.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/vector.bool.fmt/parse.pass.cpp
index c761039442196..abae40d78b23a 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/vector.bool.fmt/parse.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/vector.bool.fmt/parse.pass.cpp
@@ -25,9 +25,9 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 #include <vector>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -41,7 +41,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/parse.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/parse.pass.cpp
index 8523bc8949717..2e75606832b43 100644
--- a/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/parse.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/parse.pass.cpp
@@ -24,9 +24,9 @@
 
 #include <cassert>
 #include <concepts>
+#include <memory>
 #include <thread>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -40,7 +40,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.bool.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.bool.pass.cpp
index efea2889ce3b5..116f78e63be09 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.bool.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.bool.pass.cpp
@@ -22,6 +22,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -38,7 +39,8 @@ void test(StringT expected, StringViewT fmt, bool arg, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.c_string.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.c_string.pass.cpp
index f363bc3032003..3125dd8b60bbd 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.c_string.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.c_string.pass.cpp
@@ -21,6 +21,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -38,7 +39,8 @@ void test(StringT expected, StringViewT fmt, const CharT* a, std::size_t offset)
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char.pass.cpp
index 554def930020a..0723547c2df27 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char.pass.cpp
@@ -22,6 +22,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -39,7 +40,8 @@ void test(StringT expected, StringViewT fmt, ArgumentT arg, std::size_t offset)
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char_array.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char_array.pass.cpp
index 295ba7f67bbc5..b0ee399a1c191 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char_array.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.char_array.pass.cpp
@@ -21,6 +21,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -51,7 +52,8 @@ struct Tester {
     static_assert(std::semiregular<decltype(formatter)>);
 
     std::same_as<typename std::basic_string_view<CharT>::iterator> auto it = formatter.parse(parse_ctx);
-    assert(it == fmt.end() - offset);
+    // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+    assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
     std::basic_string<CharT> result;
     auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
index 206b0214cf5fd..ed2614cd3af2b 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.floating_point.pass.cpp
@@ -33,6 +33,7 @@
 #include <charconv>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <string>
 #include <type_traits>
 
@@ -49,7 +50,8 @@ void test(std::basic_string_view<CharT> fmt, ArithmeticT arg, std::basic_string<
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename std::basic_string_view<CharT>::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   std::basic_string<CharT> result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.handle.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.handle.pass.cpp
index e2b3d6b3d2370..5921cc6efcecb 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.handle.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.handle.pass.cpp
@@ -21,6 +21,7 @@
 #include <charconv>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <string>
 #include <type_traits>
 
@@ -43,7 +44,8 @@ void test(std::string expected, std::string_view fmt, color arg, std::size_t off
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename std::string_view::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   std::string result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.pointer.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.pointer.pass.cpp
index aa10f34c95b79..408168e033bb6 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.pointer.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.pointer.pass.cpp
@@ -27,6 +27,7 @@
 #include <charconv>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <string>
 #include <type_traits>
 
@@ -44,7 +45,8 @@ void test(StringT expected, StringViewT fmt, PointerT arg, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.signed_integral.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.signed_integral.pass.cpp
index e5db5dac0c569..cdd56d1b882a0 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.signed_integral.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.signed_integral.pass.cpp
@@ -30,6 +30,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -46,7 +47,8 @@ void test(StringT expected, StringViewT fmt, ArithmeticT arg, std::size_t offset
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.string.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.string.pass.cpp
index 73df7464dcb7a..49f54dae26478 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.string.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.string.pass.cpp
@@ -23,6 +23,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "make_string.h"
@@ -46,7 +47,8 @@ void test(StringT expected, StringViewT fmt, StringT a, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.unsigned_integral.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.unsigned_integral.pass.cpp
index eb70115bf5de5..a9537465faf9d 100644
--- a/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.unsigned_integral.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/formatter.unsigned_integral.pass.cpp
@@ -30,6 +30,7 @@
 #include <cassert>
 #include <concepts>
 #include <iterator>
+#include <memory>
 #include <type_traits>
 
 #include "test_format_context.h"
@@ -46,7 +47,8 @@ void test(StringT expected, StringViewT fmt, ArithmeticT arg, std::size_t offset
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 
   StringT result;
   auto out = std::back_inserter(result);
diff --git a/libcxx/test/std/utilities/format/format.range/format.range.fmtdef/parse.pass.cpp b/libcxx/test/std/utilities/format/format.range/format.range.fmtdef/parse.pass.cpp
index 9f9b4d4545a89..0eb984cc2c01a 100644
--- a/libcxx/test/std/utilities/format/format.range/format.range.fmtdef/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.range/format.range.fmtdef/parse.pass.cpp
@@ -22,8 +22,8 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -37,7 +37,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/utilities/format/format.range/format.range.fmtmap/parse.pass.cpp b/libcxx/test/std/utilities/format/format.range/format.range.fmtmap/parse.pass.cpp
index daa92214845ba..99d6aa7452a02 100644
--- a/libcxx/test/std/utilities/format/format.range/format.range.fmtmap/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.range/format.range.fmtmap/parse.pass.cpp
@@ -25,8 +25,8 @@
 #include <concepts>
 #include <format>
 #include <map>
+#include <memory>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -40,7 +40,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/utilities/format/format.range/format.range.fmtset/parse.pass.cpp b/libcxx/test/std/utilities/format/format.range/format.range.fmtset/parse.pass.cpp
index 843855f4e6d07..182beff4bd168 100644
--- a/libcxx/test/std/utilities/format/format.range/format.range.fmtset/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.range/format.range.fmtset/parse.pass.cpp
@@ -24,9 +24,9 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 #include <set>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -40,7 +40,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/utilities/format/format.range/format.range.fmtstr/parse.pass.cpp b/libcxx/test/std/utilities/format/format.range/format.range.fmtstr/parse.pass.cpp
index 7acee9cb9dc51..3354de3472199 100644
--- a/libcxx/test/std/utilities/format/format.range/format.range.fmtstr/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.range/format.range.fmtstr/parse.pass.cpp
@@ -23,9 +23,9 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 
 #include "format.functions.tests.h"
-#include "test_format_context.h"
 #include "test_macros.h"
 
 template <class FormatterT, class StringViewT>
@@ -36,7 +36,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class StringViewT>
diff --git a/libcxx/test/std/utilities/format/format.range/format.range.formatter/parse.pass.cpp b/libcxx/test/std/utilities/format/format.range/format.range.formatter/parse.pass.cpp
index 87774c2620877..2d0cef11feb8c 100644
--- a/libcxx/test/std/utilities/format/format.range/format.range.formatter/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.range/format.range.formatter/parse.pass.cpp
@@ -25,8 +25,8 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -40,7 +40,8 @@ constexpr void test_parse(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT>
diff --git a/libcxx/test/std/utilities/format/format.tuple/parse.pass.cpp b/libcxx/test/std/utilities/format/format.tuple/parse.pass.cpp
index 5cabbda63dd02..8653c282bfe10 100644
--- a/libcxx/test/std/utilities/format/format.tuple/parse.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.tuple/parse.pass.cpp
@@ -24,10 +24,10 @@
 #include <cassert>
 #include <concepts>
 #include <format>
+#include <memory>
 #include <tuple>
 #include <utility>
 
-#include "test_format_context.h"
 #include "test_macros.h"
 #include "make_string.h"
 
@@ -41,7 +41,8 @@ constexpr void test(StringViewT fmt, std::size_t offset) {
   static_assert(std::semiregular<decltype(formatter)>);
 
   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
-  assert(it == fmt.end() - offset);
+  // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
+  assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
 }
 
 template <class CharT, class Arg>