How to use _Pragma operator in macro?

I'm trying to use the _Pragma operator in order to ignore a warning inside a macro:

#define RAII_BLOCK() \
    _Pragma("GCC diagnostic push \"-Wshadow\"") \
    _Pragma("GCC diagnostic ignored \"-Wshadow\"") \
    auto a = RAII(); \
    _Pragma("GCC diagnostic pop")

void foo() {
    RAII_BLOCK();
    {
        RAII_BLOCK();    
    }
}

But I see really odd behavior from gcc. If RAII_BLOCK is a macro with no arguments it works as expected: https://godbolt.org/g/J6RxDV

But if I add the parenthesis (in my use case I actually need to pass a real argument), gcc starts complaining: https://godbolt.org/g/tbNtje

Note that clang works as expected in both cases. Does anyone know how to get around this issue (while keeping the shadow warnings for the rest of the code)?