Cannot alias expression

[John Colvin]

On Monday, 21 October 2013 at 19:14:25 UTC, simendsjo wrote:
> On Monday, 21 October 2013 at 18:42:27 UTC, John Colvin wrote:
>> On Monday, 21 October 2013 at 12:58:55 UTC, John Colvin wrote:
>>> I suspect I'm being very dumb here, but I can't get my head 
>>> around this:
>>>
>>>   template B(alias A)
>>>   {
>>> 	alias B = A;
>>>   }
>>>   template C(A ...)
>>>   {
>>> 	alias C = A[0];
>>>   }
>>>   static assert(B!1 == 1); //fine
>>>   static assert(C!1 == 1); //Error: cannot alias an 
>>> expression 1
>>
>> Also:
>>
>>    struct S{}
>>
>>    template B(alias A)
>>    {
>>        alias B = A;
>>    }
>>    template C(A ...)
>>    {
>>        alias C = A[0];
>>    }
>>    pragma(msg, B!int); //Error: template instance B!(int)
>>          //does not match template declaration B(alias A)
>
> Alias doesn't take primitive types.

Why on earth not?