opDispatch and compile time parameters

[Jakob Ovrum via Digitalmars-d]

On Saturday, 14 November 2015 at 04:10:59 UTC, Steven 
Schveighoffer wrote:
> Is it me, or is this a bug?
>
> struct Foo
> {
>    template opDispatch(string s) {
>       // if you uncomment this, it compiles
>       //void opDispatch() {}
>       void opDispatch(T...)() {}
>    }
> }
>
> void main()
> {
>    Foo f;
>    f.blue!char(); // Error: no property 'blue' for type 'Foo'
> }
>
> -Steve

Usually you should explicitly instantiate opDispatch to see the 
real error message(s) that prevented opDispatch from being used, 
but in this case I can't find a way to do that. 
`f.opDispatch!("blue")!char()` is syntactically invalid, and 
aliasing doesn't work either: `alias t = f.opDispatch!"blue"; 
t!char(); // Error: need `this` for opDispatch`. I wonder what 
the real error is.