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digitalmars.D.learn - strangely silent compiler

reply Orfeo <dlang orfeo.fastmail.com> writes:
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
Aug 21 2019
parent reply Eugene Wissner <belka caraus.de> writes:
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.
Aug 21 2019
parent Orfeo <dlang orfeo.fastmail.com> writes:
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
Aug 21 2019