1 files changed, 96 insertions, 0 deletions
diff --git a/libcxx/test/std/utilities/expected/expected.void/observers/error_or.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/observers/error_or.pass.cpp
new file mode 100644
index 000000000000..db2891f61c3c
--- /dev/null
+++ b/libcxx/test/std/utilities/expected/expected.void/observers/error_or.pass.cpp
@@ -0,0 +1,96 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// template<class G = E> constexpr E error_or(G&& e) const &;
+// template<class G = E> constexpr E error_or(G&& e) &&;
+
+#include <cassert>
+#include <concepts>
+#include <expected>
+#include <type_traits>
+#include <utility>
+
+struct ConstructFromInt {
+  int value;
+  constexpr ConstructFromInt(int v) : value(v) {}
+};
+
+constexpr bool test_default_template_arg() {
+  // const &, has_value()
+  {
+    const std::expected<void, ConstructFromInt> e;
+    std::same_as<ConstructFromInt> decltype(auto) x = e.error_or(10);
+    assert(x.value == 10);
+  }
+
+  // const &, !has_value()
+  {
+    const std::expected<void, ConstructFromInt> e(std::unexpect, 5);
+    std::same_as<ConstructFromInt> decltype(auto) x = e.error_or(10);
+    assert(x.value == 5);
+  }
+
+  // &&, has_value()
+  {
+    const std::expected<void, ConstructFromInt> e;
+    std::same_as<ConstructFromInt> decltype(auto) x = std::move(e).error_or(10);
+    assert(x.value == 10);
+  }
+
+  // &&, !has_value()
+  {
+    const std::expected<void, ConstructFromInt> e(std::unexpect, 5);
+    std::same_as<ConstructFromInt> decltype(auto) x = std::move(e).error_or(10);
+    assert(x.value == 5);
+  }
+
+  return true;
+}
+
+constexpr bool test() {
+  // const &, has_value()
+  {
+    const std::expected<void, int> e;
+    std::same_as<int> decltype(auto) x = e.error_or(10);
+    assert(x == 10);
+  }
+
+  // const &, !has_value()
+  {
+    const std::expected<void, int> e(std::unexpect, 5);
+    std::same_as<int> decltype(auto) x = e.error_or(10);
+    assert(x == 5);
+  }
+
+  // &&, has_value()
+  {
+    std::expected<void, int> e;
+    std::same_as<int> decltype(auto) x = std::move(e).error_or(10);
+    assert(x == 10);
+  }
+
+  // &&, !has_value()
+  {
+    std::expected<void, int> e(std::unexpect, 5);
+    std::same_as<int> decltype(auto) x = std::move(e).error_or(10);
+    assert(x == 5);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+  test_default_template_arg();
+  static_assert(test_default_template_arg());
+
+  return 0;
+}