From c8c4b239814640f9572e2865f6cd1575df85d41b Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@microsoft.com>
Date: Fri, 24 Jan 2025 02:11:17 -0800
Subject: [PATCH 1/2] Drive-by: Don't bother to implement some member functions
 that aren't ODR-used.

Co-authored-by: Casey Carter <Casey@Carter.net>
---
 tests/std/tests/P0323R12_expected/test.cpp | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/tests/std/tests/P0323R12_expected/test.cpp b/tests/std/tests/P0323R12_expected/test.cpp
index 81335d3a8b3..c43c9978efa 100644
--- a/tests/std/tests/P0323R12_expected/test.cpp
+++ b/tests/std/tests/P0323R12_expected/test.cpp
@@ -2476,24 +2476,17 @@ static_assert(test_inherited_constructors());
 template <class T, class E>
 struct ambiguating_expected_copy_constructor_caller {
     struct const_lvalue_taker {
-        const_lvalue_taker(const expected<T, E>&) {}
+        const_lvalue_taker(const expected<T, E>&);
     };
 
-    void operator()(expected<T, E>) {}
-    void operator()(const_lvalue_taker) {}
+    void operator()(expected<T, E>);
+    void operator()(const_lvalue_taker);
 };
 
 template <class T, class E>
 struct ambiguating_expected_assignment_source {
-    operator const expected<T, E>&() && {
-        return ex;
-    }
-
-    operator expected<T, E>&&() && {
-        return move(ex);
-    }
-
-    expected<T, E> ex;
+    operator const expected<T, E>&() &&;
+    operator expected<T, E>&&() &&;
 };
 
 struct move_only {

From f401839184f001ff3d604a5cb8d624c43b09263f Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@microsoft.com>
Date: Fri, 24 Jan 2025 02:12:03 -0800
Subject: [PATCH 2/2] Expand workaround for EDG bug in `P0323R12_expected`

The IntelliSense compiler just disabled compatibility with an outdated MSVC overload resolution bug, causing an apparent regression in `P0323R12_expected`. These `static_assert`s that were previously passing - but for the wrong reason - now fail with VS trunk. It looks a lot like VSO-1601179, so let's just expand the existing conditional to cover the new failures.

Co-authored-by: Casey Carter <Casey@Carter.net>
---
 tests/std/tests/P0323R12_expected/test.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/std/tests/P0323R12_expected/test.cpp b/tests/std/tests/P0323R12_expected/test.cpp
index c43c9978efa..37476de98b0 100644
--- a/tests/std/tests/P0323R12_expected/test.cpp
+++ b/tests/std/tests/P0323R12_expected/test.cpp
@@ -2505,9 +2505,9 @@ static_assert(
 #ifndef __EDG__ // TRANSITION, VSO-1601179
 static_assert(!is_assignable_v<expected<int, char>&, ambiguating_expected_assignment_source<int, char>>);
 static_assert(!is_assignable_v<expected<void, int>&, ambiguating_expected_assignment_source<void, int>>);
-#endif // ^^^ no workaround ^^^
 static_assert(!is_assignable_v<expected<move_only, char>&, ambiguating_expected_assignment_source<move_only, char>>);
 static_assert(!is_assignable_v<expected<void, move_only>&, ambiguating_expected_assignment_source<void, move_only>>);
+#endif // ^^^ no workaround ^^^
 
 static_assert(test_lwg_3886());