variable _param_0 cannot be read at compile time

[learnfirst1]

On Wednesday, 8 August 2018 at 13:13:42 UTC, Simen Kjærås wrote:
> On Wednesday, 8 August 2018 at 12:57:43 UTC, learnfirst1 wrote:
>> Why this is a error ?
>>
>> ```
>> struct S {
>>         bool v;
>>         string x;
>> }
>>
>> S* add(A...)(ref A a) {
>>         __gshared s = S(a);
>>         return &s;
>> }
>>
>> void main(){
>>         auto p = add(true);
>> }
>> ```
>>
>> test.d(9): Error: variable _param_0 cannot be read at compile 
>> time
>
> __gshared and static need to be initialized with a value known 
> at compile-time. You're trying to give it a run-time value. You 
> can set this after it's first created:
>
> S* add(A...)(ref A a) {
>     __gshared S s;
>     s = S(a);
>     return &s;
> }
>
> That's a little kludgy, but apparently that's how it be.
>
> You also get another error message:
>> Error: function test.add!bool.add(ref bool _param_0) is not 
>> callable using argument types (bool)
>
> That's because add takes its arguments by ref, and true is a 
> literal that has no canonical address, and thus can't be passed 
> by ref. You might consider using auto ref.
>
> --
>   Simen

is there a way to pass A a... as alias into template ? so the 
code can be just like this:

__gshared S s = S(&m, false);


the binary size is short since in this case the s is static build 
int. and run a bit fast.