Workaround for DevCom-10655311

stl/inc/expected

@@ -306,11 +306,18 @@ public:
  template <class _Uty = _Ty>
  requires (!is_same_v<remove_cvref_t<_Uty>, in_place_t> && !is_same_v<remove_cvref_t<_Uty>, expected>
  && !_Is_specialization_v<remove_cvref_t<_Uty>, unexpected>
- && (!is_same_v<remove_cv_t<_Ty>, bool> || !_Is_specialization_v<remove_cvref_t<_Uty>, expected>)
+ && (!is_same_v<remove_cv_t<_Ty>, bool>
+#if defined(__clang__) || defined(__EDG__) // TRANSITION, DevCom-10655311
+ || !_Is_specialization_v<remove_cvref_t<_Uty>, expected>
+#else // ^^^ no workaround / workaround vvv
+ || !_Is_specialization_v<remove_cvref_t<_Uty>, _STD expected>
+#endif // ^^^ workaround ^^^
+ )
  && is_constructible_v<_Ty, _Uty>)
  constexpr explicit(!is_convertible_v<_Uty, _Ty>)
  expected(_Uty&& _Other) noexcept(is_nothrow_constructible_v<_Ty, _Uty>) // strengthened
- : _Value(_STD forward<_Uty>(_Other)), _Has_value(true) {}
+ : _Value(_STD forward<_Uty>(_Other)), _Has_value(true) {
+ }
 
  template <class _UErr>
  requires is_constructible_v<_Err, const _UErr&>

tests/std/tests/P0323R12_expected/test.cpp

@@ -2317,6 +2317,30 @@ void test_lwg_3843() {
 static_assert(copyable<expected<any, int>>);
 static_assert(copyable<expected<void, any>>);
 
+// Test workaround for DevCom-10655311: Class derived from std::expected can't be constructed with bool value type
+template <class T, class E>
+class DerivedFromExpected : private expected<T, E> {
+public:
+ using expected<T, E>::expected;
+ using expected<T, E>::value;
+};
+
+static_assert(is_constructible_v<DerivedFromExpected<bool, int>, bool>);
+static_assert(is_constructible_v<DerivedFromExpected<bool, int>, const bool&>);
+
+constexpr bool test_inherited_constructors() {
+ DerivedFromExpected<bool, int> wrapped_false_val(false);
+ assert(!wrapped_false_val.value());
+
+ constexpr bool true_val = true;
+ DerivedFromExpected<bool, int> wrapped_true_val(true_val);
+ assert(wrapped_true_val.value());
+
+ return true;
+}
+
+static_assert(test_inherited_constructors());
+
 int main() {
  test_unexpected::test_all();
  static_assert(test_unexpected::test_all());
@@ -2333,4 +2357,5 @@ int main() {
 
  test_reinit_regression();
  test_lwg_3843();
+ test_inherited_constructors();
 }