Why Subject is generic type?

[catcombo]

I'm not completely understand why Subject type is generic despite that generic argument is not used anywhere? Can someone explain it to me? I didn't find any explanation in the docs.

https://github.com/gleam-lang/erlang/blob/main/src/gleam/erlang/process.gleam#L64

What is the Subject's generic part of the type when I call new_subject()?

For example, in this example Subject has a String generic type, but it doesn't make any sense. I totally confused how it works.

[GearsDatapacks]

It's called a phantom type. Even though a value of that type isn't stored in the value itself, it determines what kind of values should be used in combination with it. I would recommend reading Hayleigh's blog post on phantom types.

[lpil]

That's it!

If it didn't have a type parameter there would be no way for the subject to specify what type of message it accepts.

[catcombo]

Thank you very much for explanation!