I've:
```
module anomalo.util;

// Foo doesn't exist  anywhere!!!!!

Foo toJsJson(string type, Args...)(string id, Args args) {
   static if (type == "int" || type == "outcome") {
      return Json(["id" : Json(id), "type" : Json(type), "value" : Json(0),]);
   } else {
      static assert(0, "invalid type");
   }
}

```

So:
```
$ dub build
```
No error!

```
$ /usr/bin/dmd -lib -ofliba.a -debug -g -w -I. src/anomalo/util.d -vcolumns
```

No error!

Here [github](https://github.com/o3o/anomalo) my project.

Thank you

On Wednesday, 21 August 2019 at 13:41:20 UTC, Orfeo wrote:
> I've:
> ```
> module anomalo.util;
>
> // Foo doesn't exist  anywhere!!!!!
>
> Foo toJsJson(string type, Args...)(string id, Args args) {
>    static if (type == "int" || type == "outcome") {
>       return Json(["id" : Json(id), "type" : Json(type), "value" : Json(0),]);
>    } else {
>       static assert(0, "invalid type");
>    }
> }
>
> ```
>
> So:
> ```
> $ dub build
> ```
> No error!
>
> ```
> $ /usr/bin/dmd -lib -ofliba.a -debug -g -w -I. src/anomalo/util.d -vcolumns
> ```
>
> No error!
>
> Here [github](https://github.com/o3o/anomalo) my project.
>
> Thank you

toJsJson is a template. Templates are evaluated first when they are instantiated. Compiler doesn't give an error because it doesn't compile toJsJson, because you don't instantiate it anywhere.

On Wednesday, 21 August 2019 at 13:56:51 UTC, Eugene Wissner wrote:
> On Wednesday, 21 August 2019 at 13:41:20 UTC, Orfeo wrote:
>> I've:
>> ```
>> module anomalo.util;
>>
>> // Foo doesn't exist  anywhere!!!!!
>>
>> Foo toJsJson(string type, Args...)(string id, Args args) {
>>    static if (type == "int" || type == "outcome") {
>>       return Json(["id" : Json(id), "type" : Json(type), "value" : Json(0),]);
>>    } else {
>>       static assert(0, "invalid type");
>>    }
>> }
>>
>> ```
>>
>> So:
>> ```
>> $ dub build
>> ```
>> No error!
>>
>> ```
>> $ /usr/bin/dmd -lib -ofliba.a -debug -g -w -I. src/anomalo/util.d -vcolumns
>> ```
>>
>> No error!
>>
>> Here [github](https://github.com/o3o/anomalo) my project.
>>
>> Thank you
>
> toJsJson is a template. Templates are evaluated first when they are instantiated. Compiler doesn't give an error because it doesn't compile toJsJson, because you don't instantiate it anywhere.

You're right: if I add (into util.d)

```
unittest {
   import std.stdio;
   writeln(toJsJson!"int"("a"));
}
```


voila' :
```
$ dub test

src/anomalo/util.d(3,5): Error: undefined identifier Foo
src/anomalo/util.d(13,26): Error: template instance `anomalo.util.toJsJson!"int"` error instantiating
/usr/bin/dmd failed with exit code 1.
```

Thank you