> Yes, I think this is a great idea to allow the user to configure
> server-specific things easily and automatically save it
> .dir-locals.el.
>
> The question is how. Not sure if variables is the way to go.
Rust-analyzer can emit the definition of its configuration variables as
a JSON schema. There are toml and yaml servers that hopefully
understand this schema description.
So one possibility for Eglot is to help the user to edit a
project/rust.toml or a global ~/.emacs.d/eglot/rust.toml file and
arrange to call eglot-signal-didChangeConfiguration when the user saves
the file.
I don't disagree with this, though it seems different from your first idea.
When is the .dir-locals.el written in your example, or were you imagining
a use with `dir-locals-set-class`?
Regardless, if this works, why shouldn't it be rust-mode.el's job to do exactly
this? Editing "toml" files is outside the scope of LSP.
João