Auto merge of #13676 - fasterthanlime:subtree-fix, r=Veykril

Mega-sync from `rust-lang/rust`

This essentially implements `@oli-obk's` suggestion here #13459 (comment), with `@eddyb's` help.

This PR is equivalent to 14 syncs (back and forth) between `rust-lang/rust` and `rust-lang/rust-analyzer`.

Working from this list (from bottom to top):

```
(x) a2a1d99 ⬆️ rust-analyzer
(x) 79923c3 ⬆️ rust-analyzer
(x) c60b1f6 ⬆️ rust-analyzer
(x) 8807fc4 ⬆️ rust-analyzer
(x) a99a48e ⬆️ rust-analyzer
(x) 4f55ebb ⬆️ rust-analyzer
(x) f5fde4d ⬆️ rust-analyzer
(x) 459bbb4 ⬆️ rust-analyzer
(x) 65e1dc4 ⬆️ rust-analyzer
(x) 3e358a6 ⬆️ rust-analyzer
(x) 31519bb ⬆️ rust-analyzer
(x) 8231fee ⬆️ rust-analyzer
(x) 22c8c9c ⬆️ rust-analyzer
(x) 9d2cb42 ⬆️ rust-analyzer
```

(This listed was assembled by doing a `git subtree push`, which made a branch, and looking at the new commits in that branch, picking only those that were `⬆️ rust-analyzer` commits)

We used the following commands to simulate merges in both directions:

```shell
TO_MERGE=22c8c9c40 # taken from the list above, bottom to top
git merge --no-edit --no-ff $TO_MERGE
git merge --no-edit --no-ff $(git -C ../rust log --pretty=format:'%cN | %s | %ad => %P' | rg -m1 -F "$(git show --no-patch --pretty=format:%ad $TO_MERGE)" | tee /dev/stderr | rg '.* => \S+ (\S+)$' --replace '$1')
```

We encountered no merge conflicts that Git wasn't able to solve by doing it this way.

Here's what the commit graph looks like (as shown in the Git Lens VSCode extension):

<img width="1345" alt="image" src="https://user-images.githubusercontent.com/7998310/203984523-7c1a690a-8224-416c-8015-ed6e49667066.png">

This PR closes #13459

## Does this unbreak `rust->ra` syncs?

Yes, here's how we tried:

In `rust-analyzer`:

  * check out `subtree-fix` (this PR's branch)
  * make a new branch off of it: `git checkout -b subtree-fix-merge-test`
  * simulate this PR getting merged with `git merge master`

In `rust`:

  * pull latest master
  * make a new branch: `git checkout -b test-change`
  * mess with rust-analyzer (I added a comment to `src/tools/rust-analyzer/Cargo.toml`)
  * commit
  * run `git subtree push -P src/tools/rust-analyzer ra-local final-sync` (this follows the [Clippy sync guide](https://doc.rust-lang.org/nightly/clippy/development/infrastructure/sync.html))

This created a `final-sync` branch in `rust-analyzer`.

In `rust-analyzer`:

  * `git merge --no-ff final-sync` (this follows the [Clippy sync guide](https://doc.rust-lang.org/nightly/clippy/development/infrastructure/sync.html))

Now `git log` in `rust-analyzer` shows this:

```
commit 460128387e46ddfc2b95921b2d7f6e913a3d2b9f (HEAD -> subtree-fix-merge-test)
Merge: 0513fc02a 9ce6a734f
Author: Amos Wenger <[email protected]>
Date:   Fri Nov 25 13:28:24 2022 +0100

    Merge branch 'final-sync' into subtree-fix-merge-test

commit 0513fc02a08ea9de952983624bd0a00e98044b36
Merge: 38c98d1 6918009
Author: Amos Wenger <[email protected]>
Date:   Fri Nov 25 13:28:02 2022 +0100

    Merge branch 'master' into subtree-fix-merge-test

commit 9ce6a734f37ef8e53689f1c6f427a9efafe846bd (final-sync)
Author: Amos Wenger <[email protected]>
Date:   Fri Nov 25 13:26:26 2022 +0100

    Mess with rust-analyzer just for fun
```

And `git diff 0513fc02a08ea9de952983624bd0a00e98044b36` shows this:

```patch
diff --git a/Cargo.toml b/Cargo.toml
index 286ef1e..c9e24cd19 100644
--- a/Cargo.toml
+++ b/Cargo.toml
`@@` -32,3 +32,5 `@@` debug = 0
 # ungrammar = { path = "../ungrammar" }

 # salsa = { path = "../salsa" }
+
+# lol, hi
```

## Does this unbreak `ra->rust` syncs?

Yes, here's how we tried.

From `rust`:

  * `git checkout -b sync-from-ra`
  * `git subtree pull -P src/tools/rust-analyzer ra-local subtree-fix-merge-test` (this is adapted from the [Clippy sync guide](https://doc.rust-lang.org/nightly/clippy/development/infrastructure/sync.html#performing-the-sync-from-clippy-to-rust-langrust), you would normally use `ra-upstream master` but we're simulating things here)

A commit editor pops up, there was no merge conflicts.

## How do we prevent this from happening again?

Like `@bjorn3` said in #13459 (comment)

> Whenever syncing from rust-analyzer -> rust you have to immediately sync the merge commit from rust -> rust-analyzer to prevent merge conflicts in the future.

But if we get it wrong again, at least now we have a not-so-painful way to fix it.

Author: bors

bench_data/glorious_old_parser

@@ -1988,7 +1988,7 @@ impl<'a> Parser<'a> {
                     err.span_suggestion(
                         span,
                         "declare the type after the parameter binding",
-                        String::from("<identifier>: <type>"),
+                        "<identifier>: <type>",
                         Applicability::HasPlaceholders,
                     );
                 } else if require_name && is_trait_item {

crates/hir-def/src/builtin_attr.rs

@@ -379,7 +379,7 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
     // ==========================================================================
 
     rustc_attr!(rustc_allocator, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
-    rustc_attr!(rustc_allocator_nounwind, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
+    rustc_attr!(rustc_nounwind, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
     gated!(
         alloc_error_handler, Normal, template!(Word), WarnFollowing,
         experimental!(alloc_error_handler)

crates/hir-def/src/nameres.rs

@@ -57,7 +57,7 @@ mod path_resolution;
 #[cfg(test)]
 mod tests;
 
-use std::{ops::Deref, sync::Arc};
+use std::{cmp::Ord, ops::Deref, sync::Arc};
 
 use base_db::{CrateId, Edition, FileId};
 use hir_expand::{name::Name, InFile, MacroCallId, MacroDefId};

crates/hir-ty/src/autoderef.rs

@@ -1,7 +1,7 @@
 //! In certain situations, rust automatically inserts derefs as necessary: for
 //! example, field accesses `foo.bar` still work when `foo` is actually a
 //! reference to a type with the field `bar`. This is an approximation of the
-//! logic in rustc (which lives in librustc_typeck/check/autoderef.rs).
+//! logic in rustc (which lives in rustc_hir_analysis/check/autoderef.rs).
 
 use std::sync::Arc;
 

crates/hir-ty/src/infer.rs

@@ -2,7 +2,7 @@
 //! the type of each expression and pattern.
 //!
 //! For type inference, compare the implementations in rustc (the various
-//! check_* methods in librustc_typeck/check/mod.rs are a good entry point) and
+//! check_* methods in rustc_hir_analysis/check/mod.rs are a good entry point) and
 //! IntelliJ-Rust (org.rust.lang.core.types.infer). Our entry point for
 //! inference here is the `infer` function, which infers the types of all
 //! expressions in a given function.

crates/hir-ty/src/infer/coerce.rs

@@ -3,7 +3,7 @@
 //! like going from `&Vec<T>` to `&[T]`.
 //!
 //! See <https://doc.rust-lang.org/nomicon/coercions.html> and
-//! `librustc_typeck/check/coercion.rs`.
+//! `rustc_hir_analysis/check/coercion.rs`.
 
 use std::{iter, sync::Arc};
 

crates/hir-ty/src/method_resolution.rs

@@ -1,7 +1,7 @@
 //! This module is concerned with finding methods that a given type provides.
 //! For details about how this works in rustc, see the method lookup page in the
 //! [rustc guide](https://rust-lang.github.io/rustc-guide/method-lookup.html)
-//! and the corresponding code mostly in librustc_typeck/check/method/probe.rs.
+//! and the corresponding code mostly in rustc_hir_analysis/check/method/probe.rs.
 use std::{iter, ops::ControlFlow, sync::Arc};
 
 use arrayvec::ArrayVec;

crates/ide-db/src/imports/merge_imports.rs

@@ -225,7 +225,7 @@ fn path_cmp_short(a: &ast::Path, b: &ast::Path) -> Ordering {
 }
 
 /// Compares two paths, if one ends earlier than the other the has_tl parameters decide which is
-/// greater as a a path that has a tree list should be greater, while one that just ends without
+/// greater as a path that has a tree list should be greater, while one that just ends without
 /// a tree list should be considered less.
 pub(super) fn use_tree_path_cmp(
     a: &ast::Path,

crates/proc-macro-srv/src/abis/abi_sysroot/ra_server.rs

@@ -37,23 +37,6 @@ pub struct SourceFile {
 type Level = super::proc_macro::Level;
 type LineColumn = super::proc_macro::LineColumn;
 
-/// A structure representing a diagnostic message and associated children
-/// messages.
-#[derive(Clone, Debug)]
-pub struct Diagnostic {
-    level: Level,
-    message: String,
-    spans: Vec<Span>,
-    children: Vec<Diagnostic>,
-}
-
-impl Diagnostic {
-    /// Creates a new diagnostic with the given `level` and `message`.
-    pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
-        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
-    }
-}
-
 pub struct FreeFunctions;
 
 #[derive(Default)]
@@ -65,8 +48,6 @@ impl server::Types for RustAnalyzer {
     type FreeFunctions = FreeFunctions;
     type TokenStream = TokenStream;
     type SourceFile = SourceFile;
-    type MultiSpan = Vec<Span>;
-    type Diagnostic = Diagnostic;
     type Span = Span;
     type Symbol = Symbol;
 }
@@ -90,6 +71,10 @@ impl server::FreeFunctions for RustAnalyzer {
             span: tt::TokenId::unspecified(),
         })
     }
+
+    fn emit_diagnostic(&mut self, _: bridge::Diagnostic<Self::Span>) {
+        // FIXME handle diagnostic
+    }
 }
 
 impl server::TokenStream for RustAnalyzer {
@@ -282,30 +267,6 @@ impl server::SourceFile for RustAnalyzer {
     }
 }
 
-impl server::Diagnostic for RustAnalyzer {
-    fn new(&mut self, level: Level, msg: &str, spans: Self::MultiSpan) -> Self::Diagnostic {
-        let mut diag = Diagnostic::new(level, msg);
-        diag.spans = spans;
-        diag
-    }
-
-    fn sub(
-        &mut self,
-        _diag: &mut Self::Diagnostic,
-        _level: Level,
-        _msg: &str,
-        _spans: Self::MultiSpan,
-    ) {
-        // FIXME handle diagnostic
-        //
-    }
-
-    fn emit(&mut self, _diag: Self::Diagnostic) {
-        // FIXME handle diagnostic
-        // diag.emit()
-    }
-}
-
 impl server::Span for RustAnalyzer {
     fn debug(&mut self, span: Self::Span) -> String {
         format!("{:?}", span.0)
@@ -372,18 +333,6 @@ impl server::Span for RustAnalyzer {
     }
 }
 
-impl server::MultiSpan for RustAnalyzer {
-    fn new(&mut self) -> Self::MultiSpan {
-        // FIXME handle span
-        vec![]
-    }
-
-    fn push(&mut self, other: &mut Self::MultiSpan, span: Self::Span) {
-        //TODP
-        other.push(span)
-    }
-}
-
 impl server::Symbol for RustAnalyzer {
     fn normalize_and_validate_ident(&mut self, string: &str) -> Result<Self::Symbol, ()> {
         // FIXME: nfc-normalize and validate idents

crates/rust-analyzer/src/bin/logger.rs

@@ -132,7 +132,7 @@ where
 
             let ext = span.extensions();
 
-            // `FormattedFields` is a a formatted representation of the span's
+            // `FormattedFields` is a formatted representation of the span's
             // fields, which is stored in its extensions by the `fmt` layer's
             // `new_span` method. The fields will have been formatted
             // by the same field formatter that's provided to the event