Variadic function not recognizing static array length

[Zach the Mystic]

On Tuesday, 12 March 2013 at 23:35:28 UTC, Ali Çehreli wrote:
> On 03/12/2013 04:10 PM, Zach the Mystic wrote:
> > On Tuesday, 12 March 2013 at 21:47:02 UTC, Zach the Mystic
> wrote:
> >> void func(string[2] a) {}
> >>
> >> void func2(T...)(T args) {
> >> static assert(is(typeof(args[0]) == string[2]));
> >> }
> >>
> >> void func3(T...)(T args) {
> >> static assert(args[0].length == 2);
> >> }
> >>
> >> func(["",""]); // Okay
> >> func2(["",""]); // Error: (is(string[] == string[2LU])) is
> false
> >> func3(["",""]); // Error: _param_0 cannot be read at compile
> time
> >>
> >> Is this the intended design? Is there a workaround which
> allows me to
> >> ensure that the parameter is exactly 2 length?
> >
> > I'm just going to assert at runtime instead of at compile
> time.
> > assert(args[0].length == 2);
> >
> > That's a good workaround, only a minor inconvenience it can't
> be caught
> > at compile time.
>
> Actually, this is not about variadic function templates. The 
> type of an array literal is a slice:
>
>     static assert(is(typeof(["",""]) == string[]));
>
> This doesn't help you but it is possible to cast:
>
>     static assert(is(typeof(cast(string[2])["",""]) == 
> string[2]));
>
> or use a variable with an explicit type:
>
>     string[2] var = ["", ""];
>     static assert(is(typeof(var) == string[2]));
>
> Ali

Thanks. I see that the type is a slice, but it doesn't stop 
func(string[2]) from taking ["",""] at compile time. I think it 
might have been felt to be problematic not to allow it. I think 
it's inconsistent though. Might be harder to include in complex 
parameter deduction than in explicit parameter lists.