Cannot use local 'i' as parameter to non-global template

[Nicholas Wilson via Digitalmars-d-learn]

On Saturday, 7 November 2015 at 15:04:41 UTC, maik klein wrote:
> template IsSame(T){
>   template As(alias t){
>     enum As = is(T : typeof(t));
>   }
> }
> void main()
> {
>   int i;
>   enum b = IsSame!int.As!(i);
> }
>
> Err:
>
> Error: template instance As!(i) cannot use local 'i' as 
> parameter to non-global template As(alias t) dmd failed with 
> exit code 1
> I don't understand the error message.
>
> I also tried
>
> template IsSame(T){
>   enum As(alias t) = is(T : typeof(t));
> }
>
> Which results in
>
> Error: template app.IsSame!int.As cannot deduce function from 
> argument types !()(int), candidates are: source/app.d(50,8):
> app.IsSame!int.As(alias t)
>
> What am I doing wrong?
>
> Ps: Also posted on SO 
> https://stackoverflow.com/questions/33584130/cannot-use-local-i-as-parameter-to-non-global-template not sure where people usually ask questions about D.

Two ways to go about doing this

template IsSame(T,U)
{
      enum IsSame = is(T : U)
}

or make i a "global" by using a template
alias Identity(T) = T;

  template IsSame(T){
    enum As(alias t) = is(T : typeof(t));
}

enum b = IsSame!int.As!Identity!(i);