Is this a bug?

[Robert Clipsham]

I've been staring blankly at this for a while now and want some input 
from others:

----
void foo(T, U...)(bool arg)
{
     if (arg)
     {
         assert(T.tupleof.length == U.length);
         assert(arg); /* Line 6 */
         // Or some other code here
     }
}
struct A {}
void main()
{
     foo!(A, int)(false);
}
----

When compiled with warnings:

$ dmd -w test.d
test.d(6): Warning: statement is not reachable

So what appears to be happening here is that dmd is constant folding 
T.tupleof.length == U.length to false, then assert(arg) can never 
happen, so the warning is given.

It is obvious, however, that the assertion will never be executed 
anyway. Has anyone else run into this situation? The compile time 
parameters only need to match based on the runtime value provided (other 
branches in the code don't have such strict requirements for the compile 
time parameters).

Is there some way around this? (other than compiling without -w)
I can't help but feel what I'm doing isn't right some how.

Apologies if this makes no sense, I'm rather tired.

-- 
Robert
http://octarineparrot.com/