Promotion rules ... why no float?

[Sai via Digitalmars-d]

Consider this:

import std.stdio;
void main()
{
	byte a = 6, b = 7;
	auto c = a + b;
	auto d = a / b;
	writefln("%s, %s", typeof(c).stringof, c);
	writefln("%s, %s", typeof(d).stringof, d);
}

Output :
int, 13
int, 0

I really wish d gets promoted to a float. Besides C 
compatibility, any reason why d got promoted only to int even at 
the risk of serious bugs and loss of precision?

I know I could have typed "auto a = 6.0" instead, but still it 
feels like an half-baked promotion rules.