Question

I have a section of code that can be summarised as follows;

void MyFunc()
{
   int x;
'
'
   x;  
'
'
}

I would have thought that simply referencing a variable, without modifying it in anyway or using its value in anyway should generate a warning. In VS2003 it does neither, and it I need lint to pick it up.

I realise it doesn’t effect execution, but since it is a piece of code that does nothing, and the programmer doubtless intended to do something, why is it not flagged?

Similarly would you expect x = x to be a warning?

Edit: Modified question, as this constitutes a good candidate for a warning, but is not an error. Replies suggest this is handled better with other compilers. Will try out VS2008 later and post result.

Answer 1

You need to use a better compiler 🙂 Compiled with the -Wall and -pedantic flags, the GCC C++ compiler given this code:

int main() {
    int x = 0;
    x;
}

produces this diagnostic:

ma.cpp:3: warning: statement has no effect