Update .drone.jsonnet

.drone.jsonnet

@@ -370,12 +370,19 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     ),
 
     linux_pipeline(
-        "Linux 25.04 Clang 20",
-        "cppalliance/droneubuntu2504:1",
+        "Linux 24.04 Clang 20",
+        "cppalliance/droneubuntu2404:1",
         { TOOLSET: 'clang', COMPILER: 'clang++-20', CXXSTD: '03,11,14,17,20,23,2c' },
         "clang-20",
     ),
 
+    linux_pipeline(
+        "Linux 25.10 Clang 21",
+        "cppalliance/droneubuntu2510:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-21', CXXSTD: '03,11,14,17,20,23,2c' },
+        "clang-21",
+    ),
+
     macos_pipeline(
         "MacOS 10.15 Xcode 12.2 UBSAN",
         { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + ubsan,
@@ -386,6 +393,18 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,1z' } + asan,
     ),
 
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.2.1 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        xcode_version = "13.2.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.2.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        xcode_version = "13.2.1", osx_version = "monterey", arch = "arm64",
+    ),
+
     macos_pipeline(
         "MacOS 12.4 Xcode 13.4.1 UBSAN",
         { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
@@ -398,6 +417,18 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
     ),
 
+    macos_pipeline(
+        "MacOS 14 Xcode 16.2.0 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + ubsan,
+        xcode_version = "16.2.0", osx_version = "sonoma", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 14 Xcode 16.2.0 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '03,11,14,17,20,2b' } + asan,
+        xcode_version = "16.2.0", osx_version = "sonoma", arch = "arm64",
+    ),
+
     windows_pipeline(
         "Windows VS2015 msvc-14.0",
         "cppalliance/dronevs2015",

include/boost/describe/detail/config.hpp

@@ -45,4 +45,20 @@
 
 #define BOOST_DESCRIBE_INLINE_CONSTEXPR BOOST_DESCRIBE_INLINE_VARIABLE BOOST_DESCRIBE_CONSTEXPR_OR_CONST
 
+#if __cplusplus >= 202002L || ( defined(_MSVC_LANG) && _MSVC_LANG >= 202002L )
+
+# define BOOST_DESCRIBE_CXX20
+
+// Clang 13.0 is needed for unevaluated lambdas
+# if defined(__clang__) && __clang_major__ < 13
+#  undef BOOST_DESCRIBE_CXX20
+# endif
+
+// Apple Clang 13.1 is Clang 13.0
+# if defined(__clang__) && defined(__apple_build_version__) && __clang_major__ == 13 && __clang_minor__ < 1
+#  undef BOOST_DESCRIBE_CXX20
+# endif
+
+#endif
+
 #endif // #ifndef BOOST_DESCRIBE_DETAIL_CONFIG_HPP_INCLUDED

include/boost/describe/enum.hpp

@@ -43,6 +43,23 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
     return list<enum_descriptor<T>...>();
 }
 
+#if defined(BOOST_DESCRIBE_CXX20)
+
+template<auto V, auto N> struct enum_desc
+{
+    static constexpr auto value() noexcept { return V; }
+    static constexpr auto name() noexcept { return N(); }
+};
+
+#define BOOST_DESCRIBE_ENUM_BEGIN(E) \
+    inline decltype( boost::describe::detail::enum_descriptor_fn_impl( 0
+
+#define BOOST_DESCRIBE_ENUM_ENTRY(E, e) , boost::describe::detail::enum_desc<E::e, []{ return #e; }>{}
+
+#define BOOST_DESCRIBE_ENUM_END(E) ) ) boost_enum_descriptor_fn( E** ) { return {}; }
+
+#else
+
 #define BOOST_DESCRIBE_ENUM_BEGIN(E) \
     inline auto boost_enum_descriptor_fn( E** ) \
     { return boost::describe::detail::enum_descriptor_fn_impl( 0
@@ -53,6 +70,8 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
 
 #define BOOST_DESCRIBE_ENUM_END(E) ); }
 
+#endif
+
 } // namespace detail
 
 #if defined(_MSC_VER) && !defined(__clang__)

test/Jamfile

@@ -85,6 +85,8 @@ run pedantic_members_test.cpp
 
 run enum_from_string_test2.cpp ;
 
+compile nested_enum_test2.cpp ;
+
 # examples
 
 obj describe_cxx14 : describe_cxx14.cpp ;

test/nested_enum_test2.cpp

@@ -0,0 +1,24 @@
+// Copyright 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/enumerators.hpp>
+#include <boost/describe/enum.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(BOOST_DESCRIBE_CXX20)
+
+BOOST_PRAGMA_MESSAGE("Skipping test because BOOST_DESCRIBE_CXX20 isn't defined")
+
+#else
+
+struct X
+{
+    enum E { v1 };
+    BOOST_DESCRIBE_NESTED_ENUM(E, v1)
+
+    using L = boost::describe::describe_enumerators<E>;
+};
+
+#endif