CTFE determination?

[bmeck]

Hi i was messing around in D2 and noticed that the following always is saying that it is only at runtime even when the input is a constant... was wondering if there was a right way to do this.

import std.stdio;

void main(char[][] args)
{
	
	writefln("test");
	auto ct = test(cast(char[])"123");
	auto rt = test(args[0]);
	writefln(ct);
	writefln(rt);

}

pure char[] test(char[] src)
{
//	foo!(src);
	static if(__traits(compiles,foo!(src)/*check for something only available at compile time...*/))
	{
		return ((cast(char[])"argument available at compiletime of '")~src~cast(char[])"'");
	}
	else
	{
		return (cast(char[])"argument available at runtime of '")~src~(cast(char[])"'");
	}
}

pure template foo(char[] src)
{
	const uint foo = src.length;
}