gh-121647: Prefer decltype() for _Py_TYPEOF() on C++

Using MSVC (on Windows), prefer decltype() over __typeof__() on C++.

Author: vstinner

Include/pyport.h

@@ -538,15 +538,15 @@ extern "C" {
 //
 // Example: _Py_TYPEOF(x) x_copy = (x);
 //
-// On C23, use typeof(). Otherwise __typeof__() if on GCC, clang or
-// MSVC 17.9 and newer. Else if on C++11 or newer, decltype() is used.
+// On C23, use typeof(). On C++11, use decltype(). Otherwise, use __typeof__()
+// if on GCC, clang or MSVC 17.9 and newer.
 #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
 #  define _Py_TYPEOF(expr) typeof(expr)
+#elif defined(__cplusplus) && __cplusplus >= 201103L
+#  define _Py_TYPEOF(expr) decltype(expr)
 #elif defined(__GNUC__) || defined(__clang__) || \
     (defined(_MSC_VER) && _MSC_VER >= 1939)
 #  define _Py_TYPEOF(expr) __typeof__(expr)
-#elif defined(__cplusplus) && __cplusplus >= 201103L
-#  define _Py_TYPEOF(expr) decltype(expr)
 #endif