From aa3299f658f6621bfbe791dd67d0a6bdde9334d9 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 21 Jul 2023 17:01:08 -0700
Subject: [PATCH 1/2] Use lvalue references for the LHS of `is_assignable_v`
 and `is_nothrow_assignable_v`. Also cite LWG-3661 with usual syntax.

---
 .../test.cpp                                  | 60 +++++++++----------
 .../tests/P0718R2_atomic_smart_ptrs/test.cpp  | 12 ++--
 2 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/tests/std/tests/P0608R3_improved_variant_converting_constructor/test.cpp b/tests/std/tests/P0608R3_improved_variant_converting_constructor/test.cpp
index 38e604d1b7..30be63bab5 100644
--- a/tests/std/tests/P0608R3_improved_variant_converting_constructor/test.cpp
+++ b/tests/std/tests/P0608R3_improved_variant_converting_constructor/test.cpp
@@ -46,19 +46,19 @@ void assert_P0608R3() {
     static_assert(!is_constructible_v<variant<float, vector<int>>, int>);
     static_assert(!is_constructible_v<variant<float, char>, int>);
 
-    static_assert(is_assignable_v<variant<string, bool>, const char*>);
-    static_assert(is_assignable_v<variant<string, bool>, string>);
-    static_assert(is_assignable_v<variant<char, optional<char16_t>>, char16_t>);
-    static_assert(is_assignable_v<variant<int, reference_wrapper<double>>, double&>);
-    static_assert(is_assignable_v<variant<float, int>, char>);
-    static_assert(is_assignable_v<variant<float, long>, int>);
-    static_assert(is_assignable_v<variant<float, long long>, int>);
-    static_assert(is_assignable_v<variant<float, long, double>, int>);
-    static_assert(is_assignable_v<variant<float, vector<int>, long long>, int>);
-    static_assert(is_assignable_v<variant<float, int, long long>, char>);
-    static_assert(!is_assignable_v<variant<float>, int>);
-    static_assert(!is_assignable_v<variant<float, vector<int>>, int>);
-    static_assert(!is_assignable_v<variant<float, char>, int>);
+    static_assert(is_assignable_v<variant<string, bool>&, const char*>);
+    static_assert(is_assignable_v<variant<string, bool>&, string>);
+    static_assert(is_assignable_v<variant<char, optional<char16_t>>&, char16_t>);
+    static_assert(is_assignable_v<variant<int, reference_wrapper<double>>&, double&>);
+    static_assert(is_assignable_v<variant<float, int>&, char>);
+    static_assert(is_assignable_v<variant<float, long>&, int>);
+    static_assert(is_assignable_v<variant<float, long long>&, int>);
+    static_assert(is_assignable_v<variant<float, long, double>&, int>);
+    static_assert(is_assignable_v<variant<float, vector<int>, long long>&, int>);
+    static_assert(is_assignable_v<variant<float, int, long long>&, char>);
+    static_assert(!is_assignable_v<variant<float>&, int>);
+    static_assert(!is_assignable_v<variant<float, vector<int>>&, int>);
+    static_assert(!is_assignable_v<variant<float, char>&, int>);
 }
 
 void assert_P1957R2() {
@@ -67,9 +67,9 @@ void assert_P1957R2() {
     static_assert(is_constructible_v<variant<bool, int>, bitset<4>::reference>);
     static_assert(is_constructible_v<variant<bool>, bitset<4>::reference>);
 
-    static_assert(is_assignable_v<variant<bool, int>, bool>);
-    static_assert(is_assignable_v<variant<bool, int>, bitset<4>::reference>);
-    static_assert(is_assignable_v<variant<bool>, bitset<4>::reference>);
+    static_assert(is_assignable_v<variant<bool, int>&, bool>);
+    static_assert(is_assignable_v<variant<bool, int>&, bitset<4>::reference>);
+    static_assert(is_assignable_v<variant<bool>&, bitset<4>::reference>);
 }
 
 void assert_more_examples() {
@@ -89,20 +89,20 @@ void assert_more_examples() {
     static_assert(!is_constructible_v<variant<char, default_struct>, int>);
     static_assert(!is_constructible_v<variant<float, long, long long>, int>);
 
-    static_assert(is_assignable_v<variant<double_double>, double>);
-    static_assert(is_assignable_v<variant<vector<vector<int>>, optional<int>, int>, int>);
-    static_assert(is_assignable_v<variant<vector<vector<int>>, optional<int>>, int>);
-    static_assert(is_assignable_v<variant<vector<int>, optional<int>, float>, int>);
-    static_assert(is_assignable_v<variant<bool>, convertible_bool>);
-    static_assert(is_assignable_v<variant<bool, int>, convertible_bool>);
-    static_assert(is_assignable_v<variant<convertible_bool>, bool>);
-    static_assert(is_assignable_v<variant<float, bool, convertible_bool>, convertible_bool>);
-    static_assert(is_assignable_v<variant<float, bool, convertible_bool>, bool>);
-    static_assert(is_assignable_v<variant<char, int>, bool>);
-    static_assert(is_assignable_v<variant<double_double>, int>);
-    static_assert(!is_assignable_v<variant<float>, unsigned int>);
-    static_assert(!is_assignable_v<variant<char, default_struct>, int>);
-    static_assert(!is_assignable_v<variant<float, long, long long>, int>);
+    static_assert(is_assignable_v<variant<double_double>&, double>);
+    static_assert(is_assignable_v<variant<vector<vector<int>>, optional<int>, int>&, int>);
+    static_assert(is_assignable_v<variant<vector<vector<int>>, optional<int>>&, int>);
+    static_assert(is_assignable_v<variant<vector<int>, optional<int>, float>&, int>);
+    static_assert(is_assignable_v<variant<bool>&, convertible_bool>);
+    static_assert(is_assignable_v<variant<bool, int>&, convertible_bool>);
+    static_assert(is_assignable_v<variant<convertible_bool>&, bool>);
+    static_assert(is_assignable_v<variant<float, bool, convertible_bool>&, convertible_bool>);
+    static_assert(is_assignable_v<variant<float, bool, convertible_bool>&, bool>);
+    static_assert(is_assignable_v<variant<char, int>&, bool>);
+    static_assert(is_assignable_v<variant<double_double>&, int>);
+    static_assert(!is_assignable_v<variant<float>&, unsigned int>);
+    static_assert(!is_assignable_v<variant<char, default_struct>&, int>);
+    static_assert(!is_assignable_v<variant<float, long, long long>&, int>);
 }
 
 void test_variant_constructor_P0608R3() {
diff --git a/tests/std/tests/P0718R2_atomic_smart_ptrs/test.cpp b/tests/std/tests/P0718R2_atomic_smart_ptrs/test.cpp
index 0150911878..b1fc41d8d4 100644
--- a/tests/std/tests/P0718R2_atomic_smart_ptrs/test.cpp
+++ b/tests/std/tests/P0718R2_atomic_smart_ptrs/test.cpp
@@ -634,12 +634,12 @@ int main() {
     ensure_member_calls_compile<atomic<shared_ptr<int[2][2]>>>();
     ensure_member_calls_compile<atomic<weak_ptr<int[2][2]>>>();
 
-    // LWG-3893: LWG 3661 broke atomic<shared_ptr<T>> a; a = nullptr;
-    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<bool>>, nullptr_t>);
-    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int>>, nullptr_t>);
-    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[]>>, nullptr_t>);
-    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[][2]>>, nullptr_t>);
-    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[2][2]>>, nullptr_t>);
+    // LWG-3893: LWG-3661 broke atomic<shared_ptr<T>> a; a = nullptr;
+    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<bool>>&, nullptr_t>);
+    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int>>&, nullptr_t>);
+    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[]>>&, nullptr_t>);
+    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[][2]>>&, nullptr_t>);
+    static_assert(is_nothrow_assignable_v<atomic<shared_ptr<int[2][2]>>&, nullptr_t>);
 
 #ifdef _DEBUG
     sptr0 = {};

From 705a0489990eabab49b4e2a3cafd01dff849548e Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 21 Jul 2023 17:02:41 -0700
Subject: [PATCH 2/2] Check const rvalues and const lvalues in
 P2321R2_proxy_reference.

---
 tests/std/tests/P2321R2_proxy_reference/test.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/std/tests/P2321R2_proxy_reference/test.cpp b/tests/std/tests/P2321R2_proxy_reference/test.cpp
index c9180eb5f7..a49c6cbaa1 100644
--- a/tests/std/tests/P2321R2_proxy_reference/test.cpp
+++ b/tests/std/tests/P2321R2_proxy_reference/test.cpp
@@ -274,6 +274,7 @@ constexpr bool test() {
 
     { // Test vector<bool>::reference
         static_assert(is_assignable_v<const vector<bool>::reference, bool>);
+        static_assert(is_assignable_v<const vector<bool>::reference&, bool>);
 
         vector<bool> vb{false};
         const vector<bool>::reference r = vb[0];