Why can't templates use tuples for for argument types?

[Jari-Matti Mäkelä]

BCS wrote:

> Reply to Jari-Matti Mäkelä,
> 
>> Probably because the compiler does not unfold the tuple. I've filed a
>> bug about instantiating an array literal from a tuple. It has a
>> similar problem:
>> 
>> alias Tuple!(1,2,3) a;
>> 
>> int[] foo = [ a ];  // does not work, but
>> int[] foo = [ a[0], a[1], a[2] ]; // does
> 
> So you are saying it's a bug?
> 
> In that case, what is the bug number so I can add some more comments?

I think the first class tuples -bug covers this too:

http://d.puremagic.com/issues/show_bug.cgi?id=1293

If you feel it's worth a new bug report, please do as you wish.

I have to admit the situation is a bit unorthogonal - for example these work
too:

alias Tuple(int,int) a;

void foo(a b) {}
void bar() { a b; }

But 

template baz(a b) {}

doesn't.