title: Disallow using comma operator
body: <p>I never use the comma operator.<br>
  But sometimes, when I write some recursions, I make a stupid mistake: I forget the function name. That's why the last operand is returned, not the result of a recursion call.</p>
  
  <p>Simplified example:</p>
  
  <pre><code>int binpow(int a,int b){
      if(!b)
          return 1;
      if(b&amp;1)
          return a*binpow(a,b-1);
      return (a*a,b/2); // comma operator
  }
  </code></pre>
  
  <p>Is it possible get a compilation error instead of incorrect, hard to debug code?</p>