rustup should handle running RLS when the default toolchain is stable

[KalitaAlexey]

Hello everyone.

Since only nightly has the component RLS, one should either use nightly or use stable, but not use RLS.

I suppose rustup should handle the following case:

Setup

I have two toolchains: stable, nightly.
I installed the component RLS for the nightly toolchain.
I made the stable toolchain be my default.

Action

I run rls

Excepted result

rustup runs RLS from the nightly toolchain.

Actual result

rustup says RLS is not installed for stable.

What do you think about it?

[Diggsey]

What happens when rls lands on stable?

[KalitaAlexey]

Remove the approach and that's all.

[Diggsey]

I just don't think this is worthwhile, and is more likely to result in confusion. It would be too surprising to run programs from a different toolchain that the one that is active.

You can always use rls +nightly while on a stable toolchain as workaround.

[Diggsey]

Also, rustup is not intended to be tied to specific rustc versions. I'm against changes that we know will have to be reverted in a later version.