Auto merge of #6888 - matthiaskrgr:rip_ra_setup, r=flip1995

docs: update RA setup documentation

Add documentation how to get rust-analyzer to like clippys `extern crate` rustc deps.

Fixes #6883

This initially removed `cargo-dev ra_setup` but it is still needed by folks who use intellij rust, so keeping that.

changelog: none

6 files changed, 38 insertions, 16 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5954ab25d19..e0a4d4455e9 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -18,11 +18,13 @@ All contributors are expected to follow the [Rust Code of Conduct].
     - [Finding something to fix/improve](#finding-something-to-fiximprove)
   - [Writing code](#writing-code)
   - [Getting code-completion for rustc internals to work](#getting-code-completion-for-rustc-internals-to-work)
+    - [IntelliJ Rust](#intellij-rust)
+    - [Rust Analyzer](#rust-analyzer)
   - [How Clippy works](#how-clippy-works)
-  - [Syncing changes between Clippy and `rust-lang/rust`](#syncing-changes-between-clippy-and-rust-langrust)
+  - [Syncing changes between Clippy and [`rust-lang/rust`]](#syncing-changes-between-clippy-and-rust-langrust)
     - [Patching git-subtree to work with big repos](#patching-git-subtree-to-work-with-big-repos)
-    - [Performing the sync from `rust-lang/rust` to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
-    - [Performing the sync from Clippy to `rust-lang/rust`](#performing-the-sync-from-clippy-to-rust-langrust)
+    - [Performing the sync from [`rust-lang/rust`] to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
+    - [Performing the sync from Clippy to [`rust-lang/rust`]](#performing-the-sync-from-clippy-to-rust-langrust)
     - [Defining remotes](#defining-remotes)
   - [Issue and PR triage](#issue-and-pr-triage)
   - [Bors and Homu](#bors-and-homu)
@@ -105,21 +107,41 @@ quick read.
 
 ## Getting code-completion for rustc internals to work
 
-Unfortunately, [`rust-analyzer`][ra_homepage] does not (yet?) understand how Clippy uses compiler-internals
+### IntelliJ Rust
+Unfortunately, [`IntelliJ Rust`][IntelliJ_rust_homepage] does not (yet?) understand how Clippy uses compiler-internals
 using `extern crate` and it also needs to be able to read the source files of the rustc-compiler which are not
 available via a `rustup` component at the time of writing.
 To work around this, you need to have a copy of the [rustc-repo][rustc_repo] available which can be obtained via
 `git clone https://github.com/rust-lang/rust/`.
 Then you can run a `cargo dev` command to automatically make Clippy use the rustc-repo via path-dependencies
-which rust-analyzer will be able to understand.
-Run `cargo dev ra_setup --repo-path <repo-path>` where `<repo-path>` is an absolute path to the rustc repo
+which `IntelliJ Rust` will be able to understand.
+Run `cargo dev ide_setup --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
 you just cloned.
 The command will add path-dependencies pointing towards rustc-crates inside the rustc repo to
 Clippys `Cargo.toml`s and should allow rust-analyzer to understand most of the types that Clippy uses.
 Just make sure to remove the dependencies again before finally making a pull request!
 
-[ra_homepage]: https://rust-analyzer.github.io/
 [rustc_repo]: https://github.com/rust-lang/rust/
+[IntelliJ_rust_homepage]: https://intellij-rust.github.io/
+
+### Rust Analyzer
+As of [#6869][6869], [`rust-analyzer`][ra_homepage] can understand that Clippy uses compiler-internals
+using `extern crate` when `package.metadata.rust-analyzer.rustc_private` is set to `true` in Clippys `Cargo.toml.`
+You will required a `nightly` toolchain with the `rustc-dev` component installed.
+Make sure that in the `rust-analyzer` configuration, you set
+```
+{ "rust-analyzer.rustcSource": "discover" }
+```
+and
+```
+{ "rust-analyzer.updates.channel": "nightly" }
+```
+You should be able to see information on things like `Expr` or `EarlyContext` now if you hover them, also
+a lot more type hints.
+This will work with `rust-analyzer 2021-03-15` shipped in nightly `1.52.0-nightly (107896c32 2021-03-15)` or later.
+
+[ra_homepage]: https://rust-analyzer.github.io/
+[6869]: https://github.com/rust-lang/rust-clippy/pull/6869
 
 ## How Clippy works
 
diff --git a/clippy_dev/src/fmt.rs b/clippy_dev/src/fmt.rs
index a26d6aba10d..111c79c332d 100644
--- a/clippy_dev/src/fmt.rs
+++ b/clippy_dev/src/fmt.rs
@@ -90,7 +90,7 @@ pub fn run(check: bool, verbose: bool) {
             },
             CliError::RaSetupActive => {
                 eprintln!(
-                    "error: a local rustc repo is enabled as path dependency via `cargo dev ra_setup`.
+                    "error: a local rustc repo is enabled as path dependency via `cargo dev ide_setup`.
 Not formatting because that would format the local repo as well!
 Please revert the changes to Cargo.tomls first."
                 );
diff --git a/clippy_dev/src/ra_setup.rs b/clippy_dev/src/ide_setup.rs
index d0e2193ddc5..defb1133e44 100644
--- a/clippy_dev/src/ra_setup.rs
+++ b/clippy_dev/src/ide_setup.rs
@@ -55,7 +55,7 @@ fn inject_deps_into_manifest(
     // do not inject deps if we have aleady done so
     if cargo_toml.contains("[target.'cfg(NOT_A_PLATFORM)'.dependencies]") {
         eprintln!(
-            "cargo dev ra_setup: warning: deps already found inside {}, doing nothing.",
+            "cargo dev ide_setup: warning: deps already found inside {}, doing nothing.",
             manifest_path
         );
         return Ok(());
diff --git a/clippy_dev/src/lib.rs b/clippy_dev/src/lib.rs
index a95abfaceaa..a5e94683878 100644
--- a/clippy_dev/src/lib.rs
+++ b/clippy_dev/src/lib.rs
@@ -12,8 +12,8 @@ use walkdir::WalkDir;
 
 pub mod bless;
 pub mod fmt;
+pub mod ide_setup;
 pub mod new_lint;
-pub mod ra_setup;
 pub mod serve;
 pub mod stderr_length_check;
 pub mod update_lints;
diff --git a/clippy_dev/src/main.rs b/clippy_dev/src/main.rs
index 2a9f3e5348c..f4da783502c 100644
--- a/clippy_dev/src/main.rs
+++ b/clippy_dev/src/main.rs
@@ -1,7 +1,7 @@
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 
 use clap::{App, Arg, ArgMatches, SubCommand};
-use clippy_dev::{bless, fmt, new_lint, ra_setup, serve, stderr_length_check, update_lints};
+use clippy_dev::{bless, fmt, ide_setup, new_lint, serve, stderr_length_check, update_lints};
 fn main() {
     let matches = get_clap_config();
 
@@ -34,7 +34,7 @@ fn main() {
         ("limit_stderr_length", _) => {
             stderr_length_check::check();
         },
-        ("ra_setup", Some(matches)) => ra_setup::run(matches.value_of("rustc-repo-path")),
+        ("ide_setup", Some(matches)) => ide_setup::run(matches.value_of("rustc-repo-path")),
         ("serve", Some(matches)) => {
             let port = matches.value_of("port").unwrap().parse().unwrap();
             let lint = matches.value_of("lint");
@@ -138,8 +138,8 @@ fn get_clap_config<'a>() -> ArgMatches<'a> {
                 .about("Ensures that stderr files do not grow longer than a certain amount of lines."),
         )
         .subcommand(
-            SubCommand::with_name("ra_setup")
-                .about("Alter dependencies so rust-analyzer can find rustc internals")
+            SubCommand::with_name("ide_setup")
+                .about("Alter dependencies so Intellij Rust can find rustc internals")
                 .arg(
                     Arg::with_name("rustc-repo-path")
                         .long("repo-path")
diff --git a/doc/basics.md b/doc/basics.md
index c56e84e2e32..5226875cc21 100644
--- a/doc/basics.md
+++ b/doc/basics.md
@@ -88,8 +88,8 @@ cargo dev fmt
 cargo dev update_lints
 # create a new lint and register it
 cargo dev new_lint
-# (experimental) Setup Clippy to work with rust-analyzer
-cargo dev ra_setup
+# (experimental) Setup Clippy to work with IntelliJ-Rust
+cargo dev ide_setup
 ```
 
 ## lintcheck