1 files changed, 126 insertions, 0 deletions
diff --git a/libcxx/test/libcxx/utilities/expected/expected.expected/and_then.mandates.verify.cpp b/libcxx/test/libcxx/utilities/expected/expected.expected/and_then.mandates.verify.cpp
new file mode 100644
index 000000000000..692ac60d0738
--- /dev/null
+++ b/libcxx/test/libcxx/utilities/expected/expected.expected/and_then.mandates.verify.cpp
@@ -0,0 +1,126 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 and_then(F&& f) &;
+// Mandates:
+//  Let U be std::remove_cvref_t<std::invoke_result<F, decltype(value())>>
+//  U is a specialization of std::expected and std::is_same_v<U:error_type, E> is true
+
+// template<class F> constexpr auto and_then(F&& f) const &;
+// Mandates:
+//  Let U be std::remove_cvref_t<std::invoke_result<F, decltype(value())>>
+//  U is a specialization of std::expected and std::is_same_v<U:error_type, E> is true
+
+// template<class F> constexpr auto and_then(F&& f) &&;
+// Mandates:
+//  Let U be std::remove_cvref_t<std::invoke_result<F, decltype(value())>>
+//  U is a specialization of std::expected and std::is_same_v<U:error_type, E> is true
+
+// template<class F> constexpr auto and_then(F&& f) const &&;
+// Mandates:
+//  Let U be std::remove_cvref_t<std::invoke_result<F, decltype(value())>>
+//  U is a specialization of std::expected and std::is_same_v<U:error_type, E> 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<int, NotSameAsInt> lval_error_type_not_same_as_int(int&) { return {}; }
+std::expected<int, NotSameAsInt> clval_error_type_not_same_as_int(const int&) { return {}; }
+std::expected<int, NotSameAsInt> rval_error_type_not_same_as_int(int&&) { return {}; }
+std::expected<int, NotSameAsInt> crval_error_type_not_same_as_int(const int&&) { return {}; }
+
+// clang-format off
+void test() {
+  // Test & overload
+  {
+    // U is not a specialization of std::expected
+    {
+      std::expected<int, int> f1(1);
+      f1.and_then(lval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<int (&)(int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(value()) 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<U:error_type, E>
+    {
+      std::expected<int, int> f1(1);
+      f1.and_then(lval_error_type_not_same_as_int);  // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<std::expected<int, NotSameAsInt> (&)(int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(value()) must have the same error_type as this expected}}
+    }
+  }
+
+  // Test const& overload
+  {
+    // U is not a specialization of std::expected
+    {
+      const std::expected<int, int> f1(1);
+      f1.and_then(clval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<int (&)(const int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(value()) 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<U:error_type, E>
+    {
+      const std::expected<int, int> f1(1);
+      f1.and_then(clval_error_type_not_same_as_int);  // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<std::expected<int, NotSameAsInt> (&)(const int &)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(value()) must have the same error_type as this expected}}
+
+    }
+  }
+
+  // Test && overload
+  {
+    // U is not a specialization of std::expected
+    {
+      std::expected<int, int> f1(1);
+      std::move(f1).and_then(rval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<int (&)(int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(value())) 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<U:error_type, E>
+    {
+      std::expected<int, int> f1(1);
+      std::move(f1).and_then(rval_error_type_not_same_as_int); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<std::expected<int, NotSameAsInt> (&)(int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(value())) must have the same error_type as this expected}}
+    }
+  }
+
+  // Test const&& overload
+  {
+    // U is not a specialization of std::expected
+    {
+      const std::expected<int, int> f1(1);
+      std::move(f1).and_then(crval_return_not_std_expected); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<int (&)(const int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(value())) 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<U:error_type, E>
+    {
+      const std::expected<int, int> f1(1);
+      std::move(f1).and_then(crval_error_type_not_same_as_int); // expected-note{{in instantiation of function template specialization 'std::expected<int, int>::and_then<std::expected<int, NotSameAsInt> (&)(const int &&)>' requested here}}
+      // expected-error-re@*:* {{{{(static_assert|static assertion)}} failed {{.*}}The result of f(std::move(value())) must have the same error_type as this expected}}
+    }
+  }
+}
+// clang-format on