Re: This seems like what could be a common cause of bugs

[Steven Schveighoffer]

On Fri, 08 Jul 2011 18:45:58 -0400, Andrej Mitrovic  
<andrej.mitrov...@gmail.com> wrote:

This is just an observation, not a question or anything.
void main()
{
    enum width = 100;
    double step = 1 / width;

    writeln(step);  // 0
}

I've just had this bug in my code. I forgot to make either width or 1
a floating-point type. IOW, I didn't do this:

void main()
{
    enum width = 100.0;
    double step = 1 / width;   // or .1

    writeln(step);  // now 0.01
}

This seems like a very easy mistake to make. But I know the compiler
is probably powerless to do anything about it. It has an expression
resulting in an int at the RHS, and it can easily cast this to a
double since there's no obvious loss of precision when casting
int->double.

BTW, this is definitely not something the compiler can determine.  You may  
actually *want* to have integer division then convert to a double.

So a lint tool would be perfect for this -- it cannot be an error, and  
warnings don't exist in D.

-Steve