Remove mentions of Discord.

The official Discord server is no longer active (cannot be posted to).

Author: kpreid

src/doc/rustc-dev-guide/src/about-this-guide.md

@@ -74,7 +74,6 @@ You might also find the following sites useful:
  of the team procedures, active working groups, and the team calendar.
 - [std-dev-guide] -- a similar guide for developing the standard library.
 - [The t-compiler zulip][z]
-- `#contribute` and `#wg-rustup` on [Discord](https://discord.gg/rust-lang).
 - The [Rust Internals forum][rif], a place to ask questions and
  discuss Rust's internals
 - The [Rust reference][rr], even though it doesn't specifically talk about

src/doc/rustc-dev-guide/src/diagnostics/error-codes.md

@@ -20,7 +20,7 @@ explanations should help users understand why their code cannot be accepted by
 the compiler. Rust prides itself on helpful error messages and long-form
 explanations are no exception. However, before error explanations are
 overhauled[^new-explanations] it is a bit open as to how exactly they should be
-written, as always: ask your reviewer or ask around on the Rust Discord or Zulip.
+written, as always: ask your reviewer or ask around on the Rust Zulip.
 
 [^new-explanations]: See the draft RFC [here][new-explanations-rfc].
 

src/doc/rustc-dev-guide/src/getting-started.md

@@ -11,7 +11,6 @@ quick guide for the most useful things. For more information, [see this
 chapter on how to build and run the compiler](./building/how-to-build-and-run.md).
 
 [internals]: https://internals.rust-lang.org
-[rust-discord]: http://discord.gg/rust-lang
 [rust-zulip]: https://rust-lang.zulipchat.com
 [coc]: https://www.rust-lang.org/policies/code-of-conduct
 [walkthrough]: ./walkthrough.md
@@ -20,8 +19,7 @@ chapter on how to build and run the compiler](./building/how-to-build-and-run.md
 ## Asking Questions
 
 If you have questions, please make a post on the [Rust Zulip server][rust-zulip] or
-[internals.rust-lang.org][internals]. If you are contributing to Rustup, be aware they are not on
-Zulip - you can ask questions in `#wg-rustup` [on Discord][rust-discord].
+[internals.rust-lang.org][internals].
 See the [list of teams and working groups][governance] and [the Community page][community] on the
 official website for more resources.
 
@@ -30,10 +28,12 @@ official website for more resources.
 
 As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
 
-The compiler team (or `t-compiler`) usually hangs out in Zulip [in this
-"stream"][z]; it will be easiest to get questions answered there.
+The compiler team (or `t-compiler`) usually hangs out in Zulip in
+[the #t-compiler channel][z-t-compiler];
+questions about how the compiler works can go in [#t-compiler/help][z-help].
 
-[z]: https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler
+[z-t-compiler]: https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler
+[z-help]: https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp
 
 **Please ask questions!** A lot of people report feeling that they are "wasting
 expert time", but nobody on `t-compiler` feels this way. Contributors are
@@ -162,15 +162,12 @@ incredibly helpful:
 - [Triaging issues][triage]: categorizing, replicating, and minimizing issues is very helpful to the Rust maintainers.
 - [Working groups][wg]: there are a bunch of working groups on a wide variety
  of rust-related things.
-- Answer questions in the _Get Help!_ channels on the [Rust Discord
- server][rust-discord], on [users.rust-lang.org][users], or on
- [StackOverflow][so].
+- Answer questions on [users.rust-lang.org][users], or on [Stack Overflow][so].
 - Participate in the [RFC process](https://github.com/rust-lang/rfcs).
 - Find a [requested community library][community-library], build it, and publish
  it to [Crates.io](http://crates.io). Easier said than done, but very, very
  valuable!
 
-[rust-discord]: https://discord.gg/rust-lang
 [users]: https://users.rust-lang.org/
 [so]: http://stackoverflow.com/questions/tagged/rust
 [community-library]: https://github.com/rust-lang/rfcs/labels/A-community-library