No struct defined in changeset

You can’t reference the current module like that you’ll need to reference User by it’s full namespace or by using __MODULE__.

def changeset_update_comments(%__MODULE__{} = user, comment) do
...

You could also alias the local module which will allow you to reference as you are now.

  alias __MODULE__

Thanks didn’t know that you can’t do it like this alias MediumGraphqlApi.Blog.Comment

I will try your suggestion and select the solution button of it works is that okay?

I wouldn’t match on the struct for changeset functions because sometimes you already have a changeset and you want to cast additional parameters into it. Ecto.Changeset.cast does accept both as first argument.

How would be the best way to do it?

I just do changeset(struct_or_changeset, params) and be fine. Ecto.Changeset.cast will already yell if I try to use the function with non supported input.

So in this case I would create a single changset not a pattern match between changesets as i have now?

Something like this?:
Move everything into a single changeset?

def changeset(%User{} = user, comment) do
    user
    |> cast(%{}, [:username, :email, :password, :role, :confirmed, :attempts, :locked])
    |> validate_required([:username, :email, :password, :role, :confirmed, :attempts, :locked])
    |> put_assoc(:comment, comment)
  end

Well it doesn’t yeld any errors, so probably this is what you ,meant by

Thank you everyone for helping me identify the problems and also propose new ways to write the same code better.

So thanks to @sjoconnor and @LostKobrakai