Add multiple tests from different bug reports and make sure that ever… (#222)

…ything works with new unsafe_declval and with sturctured binding pack

Fixes: https://github.com/boostorg/pfr/issues/208,  https://github.com/boostorg/pfr/issues/110, https://github.com/boostorg/pfr/issues/126
Closes: https://github.com/boostorg/pfr/pull/212
Relates: https://github.com/boostorg/pfr/issues/173

.github/workflows/ci.yml

@@ -260,7 +260,6 @@ jobs:
           rm -rf build_module
 
       - name: Run tests
-        if: ${{matrix.os != 'windows-2025'}}  # TODO: workaround issues
         shell: cmd
         run: |
           cd ../boost-root

include/boost/pfr/detail/core_name20_static.hpp

@@ -216,8 +216,8 @@ constexpr std::string_view get_name() noexcept {
         "====================> Boost.PFR: It is impossible to extract name from old C array since it doesn't have named members"
     );
     static_assert(
-        sizeof(T) && BOOST_PFR_USE_CPP17,
-        "====================> Boost.PFR: Extraction of field's names is allowed only when the BOOST_PFR_USE_CPP17 macro enabled."
+        sizeof(T) && (BOOST_PFR_USE_CPP17 || BOOST_PFR_USE_CPP26),
+        "====================> Boost.PFR: Extraction of field's names is allowed only when the BOOST_PFR_USE_CPP17 or the BOOST_PFR_USE_CPP26 macro enabled."
    );
 
    return stored_name_of_field<T, I>.data();

test/core/fields_count_immutable.cpp

@@ -0,0 +1,37 @@
+// Copyright (c) 2025-2025 Antony Polukhin
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// Test from https://github.com/boostorg/pfr/issues/126
+
+#include <boost/pfr.hpp>
+
+struct NoCopy {
+    NoCopy() = default;
+    NoCopy(NoCopy const&) = delete;
+    NoCopy(NoCopy&&) = delete;
+    NoCopy& operator=(NoCopy&&) = delete;
+    NoCopy& operator=(NoCopy const&) = delete;
+};
+
+struct Group {
+    NoCopy m;
+    NoCopy m2;
+    NoCopy m3;
+    NoCopy m4;
+};
+
+Group ReturnGroup() { return {};}
+
+int main()
+{   
+#ifdef __cpp_lib_is_aggregate
+    static_assert(std::is_aggregate_v<Group>, "Group is totally an aggregate");
+#endif
+    static_assert(BOOST_PFR_HAS_GUARANTEED_COPY_ELISION, "Compiler implements mandatory copy elision");
+    Group aggregate_init_test{{}, {}, {}, {}};
+    Group elision_test = ReturnGroup();
+    return  boost::pfr::tuple_size_v<Group>;
+}
+

test/core/run/get_rvalue.cpp

@@ -20,8 +20,17 @@ void test_get_rvalue() {
         std::make_unique<int>(43),
     };
 
+    // Some _MSC_VER are broken:
+    // boost/pfr/detail/fields_count.hpp(469): error C2338: static_assert failed:
+    // '====================> Boost.PFR: If there's no other failed static
+    // asserts then something went wrong. Please report this issue to the github
+    // along with the structure you're reflecting.'
+    //
+    // No known workaround
+#if !defined(_MSC_VER) || _MSC_VER != 1944 || !(BOOST_PFR_USE_CPP17 || BOOST_PFR_USE_LOOPHOLE)
     auto p = boost::pfr::get<0>(std::move(x));
     BOOST_TEST_EQ(*p, 42);
+#endif
 }
 
 int main() {

test/core/run/issue30.cpp

@@ -9,6 +9,15 @@
 #include <boost/pfr.hpp>
 #include <boost/core/lightweight_test.hpp>
 
+// Some _MSC_VER are broken:
+// boost/pfr/detail/fields_count.hpp(469): error C2338: static_assert failed:
+// '====================> Boost.PFR: If there's no other failed static
+// asserts then something went wrong. Please report this issue to the github
+// along with the structure you're reflecting.'
+//
+// No known workaround
+#if !defined(_MSC_VER) || _MSC_VER != 1944 || !(BOOST_PFR_USE_CPP17 || BOOST_PFR_USE_LOOPHOLE)
+
 struct Message {
   std::unique_ptr<int> data;
 };
@@ -35,3 +44,9 @@ int main() {
 
   return boost::report_errors();
 }
+
+#else
+int main() {
+  return boost::report_errors();
+}
+#endif

test/core/run/tie_anonymous.cpp

@@ -7,6 +7,7 @@
 
 #include <boost/pfr/core.hpp>
 
+#include <memory>
 #include <string>
 #include <type_traits>
 
@@ -47,6 +48,12 @@ struct other_anon_with_optional {
     std::optional<some::struct2> d;
 
 };
+
+// from https://github.com/boostorg/pfr/issues/110
+struct optional_linked_list {
+    int value;
+    std::optional<std::unique_ptr<optional_linked_list>> next;
+};
 #endif
 
 struct other_anon {
@@ -93,6 +100,8 @@ void test_in_non_non_ns() {
     other_anon_with_optional opt{"test again", {}, {}, {}};
     auto opt_val = boost::pfr::structure_tie(opt);
     BOOST_TEST_EQ(std::get<0>(opt_val), "test again");
+
+    static_assert(boost::pfr::tuple_size_v<optional_linked_list> == 2, "");
 #endif
 }
 

test/core_name/run/unique_ptr_wrapper.cpp

@@ -0,0 +1,63 @@
+// Copyright (c) 2025-2025 Antony Polukhin
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/pfr.hpp>
+
+// Test inspired by https://github.com/boostorg/pfr/issues/208
+
+#include <atomic>
+#include <memory>
+#include <string>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+template <typename T>
+struct Field {
+  Field() = default;
+
+  template<typename Arg, class = decltype(T{std::declval<Arg&&>()})>
+  constexpr Field(Arg&& arg) : value_{std::forward<Arg>(arg)} {}
+
+ private:
+  [[no_unique_address]] T value_;
+};
+
+struct CustomFields2 {
+  Field<int> some_int;
+  Field<std::vector<int>> some_vector;
+  Field<std::unique_ptr<int>> some_unique_ptr;
+  Field<std::shared_ptr<int>> some_shared_ptr;
+  Field<std::atomic<int>> some_atomic;
+};
+
+int main() {
+
+// Compilers have issues with this test in C++17.
+//
+// GCC-9 and GCC-10 are fine
+//
+// GCC-11:
+// ./boost/pfr/detail/fields_count.hpp:351:58:   in constexpr expansion of boost::pfr::detail::fields_count_binary_search<CustomFields2, 0, 5>((boost::pfr::detail::is_one_element_range<0, 5>{}, boost::pfr::detail::is_one_element_range<0, 5>()), 1)
+// libs/pfr/test/core_name/run/unique_ptr_wrapper.cpp:23:32: error: use of deleted function std::atomic<int>::atomic(const std::atomic<int>&)
+//    23 |   constexpr Field(Arg&& arg) : value_{std::forward<Arg>(arg)} {}
+//       |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// GCC-12:
+// libs/pfr/test/core_name/run/unique_ptr_wrapper.cpp:39:39:   required from here
+// libs/pfr/test/core_name/run/unique_ptr_wrapper.cpp:23:32: error: use of deleted function std::unique_ptr<_Tp, _Dp>::unique_ptr(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = int]
+//    23 |   constexpr Field(Arg&& arg) : value_{std::forward<Arg>(arg)} {}
+//       |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// GCC-14 is fine
+//
+// Because of the above issues we test mostly in C++26.
+
+#if BOOST_PFR_USE_CPP26 || (defined(__GNUC__) && (__GNUC__ != 11 && __GNUC__ != 12)) || defined(__clang__)
+  CustomFields2 cf2;
+  boost::pfr::for_each_field_with_name(cf2, [](const auto&, const auto&) {});
+#endif
+}

test/core_name/run/void_ptr.cpp

@@ -0,0 +1,30 @@
+// Copyright (c) 2025-2025 Antony Polukhin
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// Test from https://github.com/boostorg/pfr/issues/173
+
+#include <boost/pfr/core.hpp>
+#include <boost/pfr/core_name.hpp>
+#include <boost/pfr/traits.hpp>
+
+#include <string_view>
+
+struct LongPointerTest {
+    long* OwningThread;
+};
+
+struct VoidPointerTest {
+    void* OwningThread;
+};
+
+int main() {
+    static_assert(boost::pfr::get_name<0, LongPointerTest>() == "OwningThread");
+
+    // No known workaround for MSVC
+#if !defined(_MSC_VER) || _MSC_VER > 1944
+    static_assert(boost::pfr::get_name<0, VoidPointerTest>() == "OwningThread");
+#endif
+}
+