Merge branch 'develop'

.github/workflows/ci.yml

@@ -142,9 +142,8 @@ jobs:
           - toolset: clang
             compiler: clang++-16
             cxxstd: "03,11,14,17,20,2b"
-            os: ubuntu-latest
+            os: ubuntu-24.04
             install: clang-16
-            container: ubuntu:24.04
           - toolset: clang
             compiler: clang++-17
             cxxstd: "03,11,14,17,20,2b"
@@ -225,10 +224,6 @@ jobs:
             cxxstd: 14,latest
             addrmd: 32,64
             os: windows-2019
-          - toolset: msvc-14.1
-            cxxstd: "11,14,17,20,latest"
-            addrmd: 32,64
-            os: windows-2019
           - toolset: msvc-14.2
             cxxstd: "14,17,20,latest"
             addrmd: 32,64

doc/28_ref_optional_semantics.qbk

@@ -2,6 +2,7 @@
     Boost.Optional
 
     Copyright (c) 2003-2007 Fernando Luis Cacciola Carballal
+    Copyright (C) 2014 - 2026 Andrzej Krzemieński.
 
     Distributed under the Boost Software License, Version 1.0.
     (See accompanying file LICENSE_1_0.txt or copy at
@@ -25,24 +26,22 @@ __SPACE__
 
 [: `constexpr optional<T>::optional() noexcept;`]
 
-* [*Effect:] Default-Constructs an `optional`.
-* [*Postconditions:] `*this` is [_uninitialized].
-* [*Notes:] T's default constructor [_is not] called.
+* [*Postconditions:] `*this` does ['not] contain a value (is "uninitialized").
+* [*Remarks:] No contained value is initialized. For every object type `T` these constructors are core constant expressions.
 * [*Example:]
 ``
-optional<T> def ;
-assert ( !def ) ;
+optional<T> oN ;
+assert ( !oN ) ;
 ``
 
 __SPACE__
 
-[#reference_optional_constructor_none_t]
 
+[#reference_optional_constructor_none_t]
 [: `constexpr optional<T>::optional( none_t ) noexcept;`]
 
-* [*Effect:] Constructs an `optional` uninitialized.
-* [*Postconditions:] `*this` is [_uninitialized].
-* [*Notes:] `T`'s default constructor [_is not] called. The expression
+* [*Postconditions:] `*this` does ['not] contain a value (is "uninitialized").
+* [*Remarks:] No contained value is initialized. For every object type `T` these constructors are core constant expressions. The expression
 `boost::none` denotes an instance of `boost::none_t` that can be used as
 the parameter.
 * [*Example:]

doc/91_comparison_with_std.qbk

@@ -47,6 +47,17 @@
   `std::ranges::find(rng, boost::none)`] [`std::vector<optional<int>> rng;`
 
   `std::ranges::find(rng, boost::optional<int>{})`] [optional<T> is never [@https://en.cppreference.com/w/cpp/concepts/equality_comparable `std::equality_comparable_with`] `nullopt_t` in `std`. ] ]
+
+  [ [```
+  void test(vector<optional<T>> rng, T val) {
+    std::ranges::find(rng, val);
+  }
+  ```] [```
+  void test(vector<optional<T>> rng, T val) {
+    std::ranges::find(rng, make_optional(val));
+  }
+  ```] [The same code for `std::optional` compiles but is ['undefined behavior] when `T` is itself an `optional`. ] ]
+
 ]
 
 

doc/92_relnotes.qbk

@@ -18,7 +18,7 @@
   `constexpr` support:
 
     * In C++11, some constructors and `const`-qualified accessors become usable
-      in compile-time contexts (are ['core constant expressions] for types
+      in compile-time contexts (are ['core constant expressions]) for types
       satisfying certain constraints.
     * In C++14 even some mutating operations become core constant expressions (those
       that do not require changing the state of `optional` from not having a value to

include/boost/optional/detail/union_optional.hpp

@@ -122,6 +122,15 @@ struct constexpr_guarded_storage
     BOOST_CXX14_CONSTEXPR void reset () noexcept { init_ = false; }
 
     //~constexpr_guarded_storage() = default;
+
+#if (defined(_MSC_VER) && 1910 <= _MSC_VER && _MSC_VER <= 1916)
+  // Workaround for MSVC 14.1x bug where it eagerly tries to define the copy/move operations
+  // these are declared but never defined
+    constexpr_guarded_storage(const constexpr_guarded_storage&);
+    constexpr_guarded_storage(constexpr_guarded_storage&&);
+    constexpr_guarded_storage& operator=(const constexpr_guarded_storage&);
+    constexpr_guarded_storage& operator=(constexpr_guarded_storage&&);
+#endif
 };
 
 
@@ -155,6 +164,15 @@ struct fallback_guarded_storage
     }
 
     ~fallback_guarded_storage() { if (init_) storage_.value_.T::~T(); }
+
+#if (defined(_MSC_VER) && 1910 <= _MSC_VER && _MSC_VER <= 1916)
+// Workaround for MSVC 14.1x bug where it eagerly tries to define the copy/move operations
+// These are declared but never defined
+  fallback_guarded_storage(const fallback_guarded_storage&);
+  fallback_guarded_storage(fallback_guarded_storage&&);
+  fallback_guarded_storage& operator=(const fallback_guarded_storage&);
+  fallback_guarded_storage& operator=(fallback_guarded_storage&&);
+#endif
 };
 
 
@@ -349,7 +367,9 @@ namespace boost {
     }
 
     template <typename U,
-              BOOST_OPTIONAL_REQUIRES(::std::is_constructible<T, U&&>)>
+              BOOST_OPTIONAL_REQUIRES(::std::is_constructible<T, U&&>),
+              BOOST_OPTIONAL_REQUIRES(!optional_detail::is_typed_in_place_factory<U>),
+              BOOST_OPTIONAL_REQUIRES(!optional_detail::is_in_place_factory<U>)>
     constexpr explicit optional(U&& v)
     : storage(optional_ns::in_place_init, optional_detail::forward_<U>(v))
     {}
@@ -463,7 +483,9 @@ namespace boost {
               BOOST_OPTIONAL_REQUIRES(!::std::is_same<typename ::std::decay<U>::type, optional>),
               BOOST_OPTIONAL_REQUIRES(!optional_detail::conjunction<::std::is_scalar<T>, ::std::is_same<T, BOOST_OPTIONAL_DECAY(U)>>),
               BOOST_OPTIONAL_REQUIRES(::std::is_constructible<T, U>),
-              BOOST_OPTIONAL_REQUIRES(::std::is_assignable<T&, U>)
+              BOOST_OPTIONAL_REQUIRES(::std::is_assignable<T&, U>),
+              BOOST_OPTIONAL_REQUIRES(!optional_detail::is_typed_in_place_factory<U>),
+              BOOST_OPTIONAL_REQUIRES(!optional_detail::is_in_place_factory<U>)
              >
     BOOST_OPTIONAL_CXX20_CONSTEXPR optional& operator=(U&& v)
     {

test/optional_test_constexpr.cpp

@@ -10,7 +10,6 @@
 //  akrzemi1@gmail.com
 
 #include "boost/optional.hpp"
-#include <string>
 
 #ifdef BOOST_OPTIONAL_USES_UNION_IMPLEMENTATION
 
@@ -130,24 +129,4 @@ namespace test_optional_ref
   static_assert(*iref == 9, "");
 }
 
-namespace test_msvc_14_1
-{
-  struct Aggr
-  {
-    boost::optional<std::string> os;
-  };
-
-  void test()
-  {
-    Aggr a;
-    Aggr b = a;
-    b = a;
-    Aggr c = Aggr();
-    b = Aggr();
-    (void)a;
-    (void)b;
-    (void)c;
-  }
-}
-
 #endif // BOOST_OPTIONAL_USES_UNION_IMPLEMENTATION

test/optional_test_inplace_factory.cpp

@@ -105,9 +105,42 @@ void test_assign()
 #endif
 }
 
+// begin Boost.Log case
+
+template <typename CharT>
+struct basic_formatter
+{
+  template< typename FunT >
+  basic_formatter(FunT&& fun) {}
+
+  template< typename FunT >
+  basic_formatter& operator= (FunT&& fun)
+  {
+      return *this;
+  }
+};
+
+template< typename CharT>
+struct chained_formatter
+{
+};
+
+void test_boost_log_case()
+{
+#ifndef BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+
+  boost::optional<basic_formatter<char>> of( boost::in_place(chained_formatter<char>()) );
+  of = boost::in_place(chained_formatter<char>());
+
+#endif //BOOST_OPTIONAL_NO_INPLACE_FACTORY_SUPPORT
+}
+
+// end Boost.Log case
+
 int main()
 {
   test_ctor();
   test_assign();
+  test_boost_log_case();
   return boost::report_errors();
 }

test/optional_test_msvc_bug_workaround.cpp

@@ -32,6 +32,7 @@ void test()
   //BOOST_TEST(v);
   boost::optional<boost::optional<int>> vv;
   bool xx = vv?true : false;
+  (void)xx;
   BOOST_TEST_EQ(*v, 7);
 #endif
 }