Merge pull request #345 from puetzk/_MSVC_TRADITIONAL-__VA_OPT__

Fix feature detection of __VA_OPT__ for MSVC

Author: rollbear

.github/workflows/ci.yml

@@ -1675,6 +1675,13 @@ jobs:
             cc: "cl", cxx: "cl",
             cxx_standard: 20,
           }
+          - {
+            name: "Windows MSVC 2022 C++20 __cppstd",
+            os: windows-2022,
+            cc: "cl", cxx: "cl",
+            cxx_standard: 20,
+            cxx_flags: "/Zc:__cplusplus"
+          }
           - {
             name: "Windows MSVC 2022 C++20 preprocessor",
             os: windows-2022,
@@ -1729,6 +1736,13 @@ jobs:
             cc: "cl", cxx: "cl",
             cxx_standard: 20,
           }
+          - {
+            name: "Windows MSVC 2019 C++20 __cppstd",
+            os: windows-2019,
+            cc: "cl", cxx: "cl",
+            cxx_standard: 20,
+            cxx_flags: "/Zc:__cplusplus"
+          }
           - {
             name: "Windows MSVC 2019 C++20 preprocessor",
             os: windows-2019,

include/trompeloeil/mock.hpp

@@ -122,13 +122,15 @@
 #define TROMPELOEIL_NOT_IMPLEMENTED(...) __VA_ARGS__
 #endif
 
-#if defined(_MSVC_TRADITIONAL) && _MSVC_TRADITIONAL==0
-#  if _MSC_VER >= 1940
-#    define TROMPELOEIL_HAS_VA_OPT 1
-#  else
-#    define TROMPELOEIL_HAS_VA_OPT 0
+#if defined(_MSVC_TRADITIONAL)
+#  if _MSVC_TRADITIONAL==0
+#    if (_MSC_VER >= 1940) || ((_MSVC_VER >= 1926) &&  (_MSVC_LANG > 201703L))
+#      define TROMPELOEIL_HAS_VA_OPT 1
+#    else
+#      define TROMPELOEIL_HAS_VA_OPT 0
+#    endif
+#    define TROMPELOEIL_MSVC_PREPROCESSOR 0
 #  endif
-#  define TROMPELOEIL_MSVC_PREPROCESSOR 0
 #elif __cplusplus >= 202002L
 #  define TROMPELOEIL_HAS_VA_OPT 1
 #else