Add static_asserts in BOOST_DESCRIBE_ENUM and BOOST_DESCRIBE_STRUCT (fixes #8)

.github/workflows/ci.yml

@@ -159,6 +159,11 @@ jobs:
             cxxstd: "14,17,latest"
             addrmd: 32,64
             os: windows-2019
+          - toolset: msvc-14.2
+            cxxstd: "14,17,latest"
+            addrmd: 32,64
+            cxxflags: "-Zc:preprocessor"
+            os: windows-2019
           - toolset: gcc
             cxxstd: "03,11,14,17,2a"
             addrmd: 64
@@ -195,4 +200,5 @@ jobs:
         shell: cmd
         run: |
           cd ../boost-root
-          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release
+          if not "${{matrix.cxxflags}}" == "" set CXXFLAGS=cxxflags=${{matrix.cxxflags}}
+          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} %CXXFLAGS% variant=debug,release

appveyor.yml

@@ -31,6 +31,11 @@ environment:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       TOOLSET: clang-win
       CXXSTD: 14,17,latest
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      TOOLSET: msvc-14.2
+      CXXSTD: 14,17,latest
+      ADDRMD: 32,64
+      CXXFLAGS: -Zc:preprocessor
 
 install:
   - set BOOST_BRANCH=develop
@@ -49,4 +54,5 @@ build: off
 test_script:
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
   - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-  - b2 -j3 libs/describe/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+  - if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+  - b2 -j3 libs/describe/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker

include/boost/describe/class.hpp

@@ -16,6 +16,7 @@
 
 #include <boost/describe/detail/bases.hpp>
 #include <boost/describe/detail/members.hpp>
+#include <type_traits>
 
 namespace boost
 {
@@ -33,6 +34,7 @@ namespace describe
     friend BOOST_DESCRIBE_PRIVATE_MEMBERS(C, BOOST_DESCRIBE_PP_UNPACK Private)
 
 #define BOOST_DESCRIBE_STRUCT(C, Bases, Members) \
+    static_assert(std::is_class<C>::value, "BOOST_DESCRIBE_STRUCT should only be used with class types"); \
     BOOST_DESCRIBE_BASES(C, BOOST_DESCRIBE_PP_UNPACK Bases) \
     BOOST_DESCRIBE_PUBLIC_MEMBERS(C, BOOST_DESCRIBE_PP_UNPACK Members) \
     BOOST_DESCRIBE_PROTECTED_MEMBERS(C) \
@@ -58,6 +60,7 @@ namespace describe
     friend BOOST_DESCRIBE_PRIVATE_MEMBERS_(C BOOST_DESCRIBE_PP_UNPACK Private)
 
 #define BOOST_DESCRIBE_STRUCT(C, Bases, Members) \
+    static_assert(std::is_class<C>::value, "BOOST_DESCRIBE_STRUCT should only be used with class types"); \
     BOOST_DESCRIBE_BASES_(C BOOST_DESCRIBE_PP_UNPACK Bases) \
     BOOST_DESCRIBE_PUBLIC_MEMBERS_(C BOOST_DESCRIBE_PP_UNPACK Members) \
     BOOST_DESCRIBE_PROTECTED_MEMBERS_(C) \

include/boost/describe/enum.hpp

@@ -5,8 +5,6 @@
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
-#include <boost/describe/detail/pp_for_each.hpp>
-#include <boost/describe/detail/list.hpp>
 #include <boost/describe/detail/config.hpp>
 
 #if !defined(BOOST_DESCRIBE_CXX14)
@@ -15,6 +13,10 @@
 
 #else
 
+#include <boost/describe/detail/pp_for_each.hpp>
+#include <boost/describe/detail/list.hpp>
+#include <type_traits>
+
 namespace boost
 {
 namespace describe
@@ -53,6 +55,7 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
 #if defined(_MSC_VER) && !defined(__clang__)
 
 #define BOOST_DESCRIBE_ENUM(E, ...) \
+    static_assert(std::is_enum<E>::value, "BOOST_DESCRIBE_ENUM should only be used with enums"); \
     BOOST_DESCRIBE_ENUM_BEGIN(E) \
     BOOST_DESCRIBE_PP_FOR_EACH(BOOST_DESCRIBE_ENUM_ENTRY, E, __VA_ARGS__) \
     BOOST_DESCRIBE_ENUM_END(E)
@@ -60,6 +63,7 @@ template<class... T> auto enum_descriptor_fn_impl( int, T... )
 #else
 
 #define BOOST_DESCRIBE_ENUM(E, ...) \
+    static_assert(std::is_enum<E>::value, "BOOST_DESCRIBE_ENUM should only be used with enums"); \
     BOOST_DESCRIBE_ENUM_BEGIN(E) \
     BOOST_DESCRIBE_PP_FOR_EACH(BOOST_DESCRIBE_ENUM_ENTRY, E, ##__VA_ARGS__) \
     BOOST_DESCRIBE_ENUM_END(E)

test/Jamfile

@@ -41,12 +41,15 @@ run overloaded_test2.cpp ;
 
 compile test_d_type.cpp ;
 
+compile-fail enum_struct_fail.cpp ;
+compile-fail struct_enum_fail.cpp ;
+
 obj describe_cxx14 : describe_cxx14.cpp ;
 explicit describe_cxx14 ;
 
 local CXX14 = [ check-target-builds describe_cxx14 describe_cxx14 : : <build>no ] ;
 
-local JSON = <library>/boost//json/<warnings>off "<toolset>msvc-14.0:<build>no" ;
+local JSON = <library>/boost//json/<warnings>off "<toolset>msvc-14.0:<build>no" "<toolset>msvc-14.2:<cxxflags>-wd5104" ;
 local SERIALIZATION = <library>/boost//serialization/<warnings>off "-<toolset>clang:<warnings-as-errors>on" ;
 
 run ../example/printing_enums_ct.cpp : : : $(CXX14) ;

test/enum_struct_fail.cpp

@@ -0,0 +1,16 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/class.hpp>
+
+#if !defined(BOOST_DESCRIBE_CXX14)
+
+#error "Skipping test because C++14 is not available"
+
+#else
+
+enum E1 {};
+BOOST_DESCRIBE_STRUCT(E1, (), ())
+
+#endif // !defined(BOOST_DESCRIBE_CXX14)

test/struct_enum_fail.cpp

@@ -0,0 +1,16 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/describe/enum.hpp>
+
+#if !defined(BOOST_DESCRIBE_CXX14)
+
+#error "Skipping test because C++14 is not available"
+
+#else
+
+struct X {};
+BOOST_DESCRIBE_ENUM(X)
+
+#endif // !defined(BOOST_DESCRIBE_CXX14)