1 files changed, 125 insertions, 0 deletions
diff --git a/libcxx/test/libcxx/utilities/expected/expected.expected/or_else.mandates.verify.cpp b/libcxx/test/libcxx/utilities/expected/expected.expected/or_else.mandates.verify.cpp
new file mode 100644
index 000000000000..1264cc06b48c
--- /dev/null
+++ b/libcxx/test/libcxx/utilities/expected/expected.expected/or_else.mandates.verify.cpp
@@ -0,0 +1,125 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+// Test the mandates
+// template<class F> constexpr auto or_else(F&& f) &;
+// Mandates:
+//  Let G be std::remove_cvref_t<std::invoke_result<F, decltype(error())>>
+//  G is a specialization of std::expected and std::is_same_v<G:value_type, T> is true
+
+// template<class F> constexpr auto or_else(F&& f) const &;
+// Mandates:
+//  Let G be std::remove_cvref_t<std::invoke_result<F, decltype(error())>>
+//  G is a specialization of std::expected and std::is_same_v<G:value_type, T> is true
+
+// template<class F> constexpr auto or_else(F&& f) &&;
+// Mandates:
+//  Let G be std::remove_cvref_t<std::invoke_result<F, decltype(error())>>
+//  G is a specialization of std::expected and std::is_same_v<G:value_type, T> is true
+
+// template<class F> constexpr auto or_else(F&& f) const &&;
+// Mandates:
+//  Let G be std::remove_cvref_t<std::invoke_result<F, decltype(error())>>
+//  G is a specialization of std::expected and std::is_same_v<G:value_type, T> is true
+
+#include <expected>
+#include <utility>
+
+struct NotSameAsInt {};
+
+int lval_return_not_std_expected(int&) { return 0; }
+int clval_return_not_std_expected(const int&) { return 0; }
+int rval_return_not_std_expected(int&&) { return 0; }
+int crval_return_not_std_expected(const int&&) { return 0; }
+
+std::expected<NotSameAsInt, int> lval_error_type_not_same_as_int(int&) { return {}; }
+std::expected<NotSameAsInt, int> clval_error_type_not_same_as_int(const int&) { return {}; }
+std::expected<NotSameAsInt, int> rval_error_type_not_same_as_int(int&&) { return {}; }
+std::expected<NotSameAsInt, int> crval_error_type_not_same_as_int(const int&&) { return {}; }
+
+// clang-format off
+void test() {
+  // Test & overload
+  {
+    // G is not a specialization of std::expected
+    {
+      std::expected<int, int> f1(std::unexpected<int>(1));
+      f1.or_else(lval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<int (&)(int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(error()) must be a specialization of std::expected}}
+      // expected-error-re@*:* {{{{.*}}cannot be used prior to '::' because it has no members}}
+      // expected-error-re@*:* {{no matching constructor for initialization of{{.*}}}}
+    }
+
+    // !std::is_same_v<G:value_type, T>
+    {
+      std::expected<int, int> f1(std::unexpected<int>(1));
+      f1.or_else(lval_error_type_not_same_as_int);  // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<std::expected<NotSameAsInt, int> (&)(int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(error()) must have the same value_type as this expected}}
+    }
+  }
+
+  // Test const& overload
+  {
+    // G is not a specialization of std::expected
+    {
+      const std::expected<int, int> f1(std::unexpected<int>(1));
+      f1.or_else(clval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<int (&)(const int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(error()) must be a specialization of std::expected}}
+      // expected-error-re@*:* {{{{.*}}cannot be used prior to '::' because it has no members}}
+      // expected-error-re@*:* {{no matching constructor for initialization of{{.*}}}}
+    }
+
+    // !std::is_same_v<G:value_type, T>
+    {
+      const std::expected<int, int> f1(std::unexpected<int>(1));
+      f1.or_else(clval_error_type_not_same_as_int);  // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<std::expected<NotSameAsInt, int> (&)(const int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(error()) must have the same value_type as this expected}}
+    }
+  }
+
+  // Test && overload
+  {
+    // G is not a specialization of std::expected
+    {
+      std::expected<int, int> f1(std::unexpected<int>(1));
+      std::move(f1).or_else(rval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<int (&)(int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(error())) must be a specialization of std::expected}}
+      // expected-error-re@*:* {{{{.*}}cannot be used prior to '::' because it has no members}}
+      // expected-error-re@*:* {{no matching constructor for initialization of{{.*}}}}
+    }
+
+    // !std::is_same_v<G:value_type, T>
+    {
+      std::expected<int, int> f1(std::unexpected<int>(1));
+      std::move(f1).or_else(rval_error_type_not_same_as_int); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<std::expected<NotSameAsInt, int> (&)(int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(error())) must have the same value_type as this expected}}
+    }
+  }
+
+  // Test const&& overload
+  {
+    // G is not a specialization of std::expected
+    {
+      const std::expected<int, int> f1(std::unexpected<int>(1));
+      std::move(f1).or_else(crval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<int (&)(const int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(error())) must be a specialization of std::expected}}
+      // expected-error-re@*:* {{{{.*}}cannot be used prior to '::' because it has no members}}
+      // expected-error-re@*:* {{no matching constructor for initialization of{{.*}}}}
+    }
+
+    // !std::is_same_v<G:value_type, T>
+    {
+      const std::expected<int, int> f1(std::unexpected<int>(1));
+      std::move(f1).or_else(crval_error_type_not_same_as_int); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::or_else<std::expected<NotSameAsInt, int> (&)(const int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(error())) must have the same value_type as this expected}}
+    }
+  }
+}
+// clang-format on