Rollup of 6 pull requests

.mailmap

@@ -653,7 +653,7 @@ Torsten Weber <[email protected]> <[email protected]>
 Trevor Gross <[email protected]> <[email protected]>
 Trevor Gross <[email protected]> <[email protected]>
 Trevor Spiteri <[email protected]> <[email protected]>
-Tshepang Mbambo <[email protected]>
+Tshepang Mbambo <[email protected]> <[email protected]>
 Ty Overby <[email protected]>
 Tyler Mandry <[email protected]> <[email protected]>
 Tyler Ruckinger <[email protected]>

compiler/rustc_passes/src/check_attr.rs

@@ -2312,7 +2312,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     fn check_macro_use(&self, hir_id: HirId, attr: &Attribute, target: Target) {
-        let name = attr.name().unwrap();
+        let Some(name) = attr.name() else {
+            return;
+        };
         match target {
             Target::ExternCrate | Target::Mod => {}
             _ => {

compiler/rustc_resolve/src/check_unused.rs

@@ -193,6 +193,16 @@ impl<'a, 'ra, 'tcx> UnusedImportCheckVisitor<'a, 'ra, 'tcx> {
                 continue;
             }
 
+            let module = self
+                .r
+                .get_nearest_non_block_module(self.r.local_def_id(extern_crate.id).to_def_id());
+            if module.no_implicit_prelude {
+                // If the module has `no_implicit_prelude`, then we don't suggest
+                // replacing the extern crate with a use, as it would not be
+                // inserted into the prelude. User writes `extern` style deliberately.
+                continue;
+            }
+
             let vis_span = extern_crate
                 .vis_span
                 .find_ancestor_inside(extern_crate.span)

src/ci/citool/tests/jobs.rs

@@ -51,6 +51,8 @@ fn get_matrix(event_name: &str, commit_msg: &str, branch_ref: &str) -> String {
         .env("GITHUB_EVENT_NAME", event_name)
         .env("COMMIT_MESSAGE", commit_msg)
         .env("GITHUB_REF", branch_ref)
+        .env("GITHUB_RUN_ID", "123")
+        .env("GITHUB_RUN_ATTEMPT", "1")
         .stdout(Stdio::piped())
         .output()
         .expect("Failed to execute command");

src/doc/rustc-dev-guide/.mailmap

@@ -3,3 +3,4 @@ Jynn Nelson <[email protected]> <[email protected]>
 Jynn Nelson <[email protected]> <[email protected]>
 Jynn Nelson <[email protected]> <[email protected]>
 Jynn Nelson <[email protected]>
+Tshepang Mbambo <[email protected]> <[email protected]>

src/doc/rustc-dev-guide/rust-version

@@ -1 +1 @@
-e42bbfe1f7c26f8760a99c4b1f27d33aba1040bb
+99e7c15e81385b38a8186b51edc4577d5d7b5bdd

src/doc/rustc-dev-guide/src/appendix/compiler-lecture.md

@@ -46,3 +46,4 @@ These are videos where various experts explain different parts of the compiler:
 
 ## Code Generation
 - [January 2019: Cranelift](https://www.youtube.com/watch?v=9OIA7DTFQWU)
+- [December 2024: LLVM Developers' Meeting - Rust ❤️ LLVM](https://www.youtube.com/watch?v=Kqz-umsAnk8)

src/doc/rustc-dev-guide/src/borrow_check/two_phase_borrows.md

@@ -76,7 +76,7 @@ borrow.
 [`AutoBorrow`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/adjustment/enum.AutoBorrow.html
 [converted]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_build/thir/cx/expr/trait.ToBorrowKind.html#method.to_borrow_kind
 [`BorrowKind`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/enum.BorrowKind.html
-[`GatherBorrows`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/visit/trait.Visitor.html#method.visit_local
+[`GatherBorrows`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_borrowck/borrow_set/struct.GatherBorrows.html
 [`BorrowData`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_borrowck/borrow_set/struct.BorrowData.html
 
 ## Checking two-phase borrows

src/doc/rustc-dev-guide/src/building/suggested.md

@@ -91,7 +91,7 @@ for two reasons:
   additional rebuilds in some cases.
 
 To avoid these problems:
-- Add `--build-dir=build-rust-analyzer` to all of the custom `x` commands in
+- Add `--build-dir=build/rust-analyzer` to all of the custom `x` commands in
   your editor's rust-analyzer configuration.
   (Feel free to choose a different directory name if desired.)
 - Modify the `rust-analyzer.rustfmt.overrideCommand` setting so that it points
@@ -100,10 +100,7 @@ To avoid these problems:
   copy of `rust-analyzer-proc-macro-srv` in that other build directory.
 
 Using separate build directories for command-line builds and rust-analyzer
-requires extra disk space, and also means that running `./x clean` on the
-command-line will not clean out the separate build directory. To clean the
-separate build directory, run `./x clean --build-dir=build-rust-analyzer`
-instead.
+requires extra disk space.
 
 ### Visual Studio Code
 
@@ -137,7 +134,7 @@ Task] instead:
 
 ### Neovim
 
-For Neovim users there are several options for configuring for rustc. The
+For Neovim users, there are a few options. The
 easiest way is by using [neoconf.nvim](https://github.com/folke/neoconf.nvim/),
 which allows for project-local configuration files with the native LSP. The
 steps for how to use it are below. Note that they require rust-analyzer to

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

@@ -866,19 +866,17 @@ struct](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/json/struct
 (and sub-structs) for the JSON serialization. Don't confuse this with
 [`errors::Diag`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.Diag.html)!
 
-## `#[rustc_on_unimplemented(...)]`
+## `#[rustc_on_unimplemented]`
 
-The `#[rustc_on_unimplemented]` attribute allows trait definitions to add specialized
-notes to error messages when an implementation was expected but not found.
-You can refer to the trait's generic arguments by name and to the resolved type using `Self`.
-
-For example:
+This attribute allows trait definitions to modify error messages when an implementation was
+expected but not found. The string literals in the attribute are format strings and can be
+formatted with named parameters. See the Formatting
+section below for what parameters are permitted.
 
 ```rust,ignore
-#![feature(rustc_attrs)]
-
-#[rustc_on_unimplemented="an iterator over elements of type `{A}` \
-    cannot be built from a collection of type `{Self}`"]
+#[rustc_on_unimplemented(message = "an iterator over \
+    elements of type `{A}` cannot be built from a \
+    collection of type `{Self}`")]
 trait MyIterator<A> {
     fn next(&mut self) -> A;
 }
@@ -895,32 +893,26 @@ fn main() {
 When the user compiles this, they will see the following;
 
 ```txt
-error[E0277]: the trait bound `&[{integer}]: MyIterator<char>` is not satisfied
-  --> <anon>:14:5
+error[E0277]: an iterator over elements of type `char` cannot be built from a collection of type `&[{integer}]`
+  --> src/main.rs:13:19
    |
-14 |     iterate_chars(&[1, 2, 3][..]);
-   |     ^^^^^^^^^^^^^ an iterator over elements of type `char` cannot be built from a collection of type `&[{integer}]`
+13 |     iterate_chars(&[1, 2, 3][..]);
+   |     ------------- ^^^^^^^^^^^^^^ the trait `MyIterator<char>` is not implemented for `&[{integer}]`
+   |     |
+   |     required by a bound introduced by this call
    |
-   = help: the trait `MyIterator<char>` is not implemented for `&[{integer}]`
-   = note: required by `iterate_chars`
+note: required by a bound in `iterate_chars`
 ```
 
-`rustc_on_unimplemented` also supports advanced filtering for better targeting
-of messages, as well as modifying specific parts of the error message. You
-target the text of:
-
+You can modify the contents of:
  - the main error message (`message`)
  - the label (`label`)
- - an extra note (`note`)
+ - the note(s) (`note`)
 
 For example, the following attribute
 
 ```rust,ignore
-#[rustc_on_unimplemented(
-    message="message",
-    label="label",
-    note="note"
-)]
+#[rustc_on_unimplemented(message = "message", label = "label", note = "note")]
 trait MyIterator<A> {
     fn next(&mut self) -> A;
 }
@@ -930,45 +922,61 @@ Would generate the following output:
 
 ```text
 error[E0277]: message
-  --> <anon>:14:5
+  --> <file>:10:19
    |
-14 |     iterate_chars(&[1, 2, 3][..]);
-   |     ^^^^^^^^^^^^^ label
+10 |     iterate_chars(&[1, 2, 3][..]);
+   |     ------------- ^^^^^^^^^^^^^^ label
+   |     |
+   |     required by a bound introduced by this call
    |
-   = note: note
    = help: the trait `MyIterator<char>` is not implemented for `&[{integer}]`
-   = note: required by `iterate_chars`
+   = note: note
+note: required by a bound in `iterate_chars`
 ```
 
+The functionality discussed so far is also available with
+[`#[diagnostic::on_unimplemented]`](https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-diagnosticon_unimplemented-attribute).
+If you can, you should use that instead.
+
+### Filtering
+
 To allow more targeted error messages, it is possible to filter the
-application of these fields based on a variety of attributes when using
-`on`:
+application of these fields with `on`.
 
+You can filter on the following boolean flags:
  - `crate_local`: whether the code causing the trait bound to not be
    fulfilled is part of the user's crate. This is used to avoid suggesting
    code changes that would require modifying a dependency.
- - Any of the generic arguments that can be substituted in the text can be
-   referred by name as well for filtering, like `Rhs="i32"`, except for
-   `Self`.
- - `_Self`: to filter only on a particular calculated trait resolution, like
-   `Self="std::iter::Iterator<char>"`. This is needed because `Self` is a
-   keyword which cannot appear in attributes.
- - `direct`: user-specified rather than derived obligation.
- - `from_desugaring`: usable both as boolean (whether the flag is present)
-   or matching against a particular desugaring. The desugaring is identified
-   with its variant name in the `DesugaringKind` enum.
-
-For example, the `Iterator` trait can be annotated in the following way:
+ - `direct`: whether this is an user-specified rather than derived obligation.
+ - `from_desugaring`: whether we are in some kind of desugaring, like `?`
+   or a `try` block for example. This flag can also be matched on, see below.
+
+You can match on the following names and values, using `name = "value"`:
+ - `cause`: Match against one variant of the `ObligationCauseCode`
+   enum. Only `"MainFunctionType"` is supported.
+ - `from_desugaring`: Match against a particular variant of the `DesugaringKind`
+   enum. The desugaring is identified by its variant name, for example
+   `"QuestionMark"` for `?` desugaring or `"TryBlock"` for `try` blocks.
+ - `Self` and any generic arguments of the trait, like `Self = "alloc::string::String"`
+   or `Rhs="i32"`.
+
+The compiler can provide several values to match on, for example:
+  - the self_ty, pretty printed with and without type arguments resolved.
+  - `"{integral}"`, if self_ty is an integral of which the type is known.
+  - `"[]"`, `"[{ty}]"`, `"[{ty}; _]"`, `"[{ty}; $N]"` when applicable.
+  - references to said slices and arrays.
+  - `"fn"`, `"unsafe fn"` or `"#[target_feature] fn"` when self is a function.
+  - `"{integer}"` and `"{float}"` if the type is a number but we haven't inferred it yet.
+  - combinations of the above, like `"[{integral}; _]"`.
+
+For example, the `Iterator` trait can be filtered in the following way:
 
 ```rust,ignore
 #[rustc_on_unimplemented(
-    on(
-        _Self="&str",
-        note="call `.chars()` or `.as_bytes()` on `{Self}`"
-    ),
-    message="`{Self}` is not an iterator",
-    label="`{Self}` is not an iterator",
-    note="maybe try calling `.iter()` or a similar method"
+    on(Self = "&str", note = "call `.chars()` or `.as_bytes()` on `{Self}`"),
+    message = "`{Self}` is not an iterator",
+    label = "`{Self}` is not an iterator",
+    note = "maybe try calling `.iter()` or a similar method"
 )]
 pub trait Iterator {}
 ```
@@ -997,15 +1005,47 @@ error[E0277]: `&str` is not an iterator
   = note: required by `std::iter::IntoIterator::into_iter`
 ```
 
-If you need to filter on multiple attributes, you can use `all`, `any` or
-`not` in the following way:
+The `on` filter accepts `all`, `any` and `not` predicates similar to the `cfg` attribute:
 
 ```rust,ignore
-#[rustc_on_unimplemented(
-    on(
-        all(_Self="&str", T="std::string::String"),
-        note="you can coerce a `{T}` into a `{Self}` by writing `&*variable`"
-    )
-)]
-pub trait From<T>: Sized { /* ... */ }
+#[rustc_on_unimplemented(on(
+    all(Self = "&str", T = "alloc::string::String"),
+    note = "you can coerce a `{T}` into a `{Self}` by writing `&*variable`"
+))]
+pub trait From<T>: Sized {
+    /* ... */
+}
+```
+
+### Formatting 
+
+The string literals are format strings that accept parameters wrapped in braces
+but positional and listed parameters and format specifiers are not accepted.
+The following parameter names are valid:
+- `Self` and all generic parameters of the trait.
+- `This`: the name of the trait the attribute is on, without generics.
+- `Trait`: the name of the "sugared" trait. See `TraitRefPrintSugared`.
+- `ItemContext`: the kind of `hir::Node` we're in, things like `"an async block"`,
+   `"a function"`, `"an async function"`, etc.
+
+Something like:
+
+```rust,ignore
+#![feature(rustc_attrs)]
+
+#[rustc_on_unimplemented(message = "Self = `{Self}`, \
+    T = `{T}`, this = `{This}`, trait = `{Trait}`, \
+    context = `{ItemContext}`")]
+pub trait From<T>: Sized {
+    fn from(x: T) -> Self;
+}
+
+fn main() {
+    let x: i8 = From::from(42_i32);
+}
+```
+
+Will format the message into 
+```text
+"Self = `i8`, T = `i32`, this = `From`, trait = `From<i32>`, context = `a function`"
 ```

src/doc/rustc-dev-guide/src/early_late_parameters.md

@@ -174,7 +174,8 @@ As mentioned previously, the distinction between early and late bound parameters
 - When naming a function (early)
 - When calling a function (late)
 
-There currently is no syntax for explicitly specifying generic arguments for late bound parameters as part of the call step, only specifying generic arguments when naming a function. The syntax `foo::<'static>();`, despite being part of a function call, behaves as `(foo::<'static>)();` and instantiates the early bound generic parameters on the function item type.
+There is currently no syntax for explicitly specifying generic arguments for late bound parameters during the call step; generic arguments can only be specified for early bound parameters when naming a function.
+The syntax `foo::<'static>();`, despite being part of a function call, behaves as `(foo::<'static>)();` and instantiates the early bound generic parameters on the function item type.
 
 See the following example:
 ```rust

src/doc/rustc-dev-guide/src/fuzzing.md

@@ -73,21 +73,32 @@ To build a corpus, you may want to use:
 
 - The rustc/rust-analyzer/clippy test suites (or even source code) --- though avoid
   tests that are already known to cause failures, which often begin with comments
-  like `// failure-status: 101` or `// known-bug: #NNN`.
-- The already-fixed ICEs in [Glacier][glacier] --- though avoid the unfixed
-  ones in `ices/`!
+  like `//@ failure-status: 101` or `//@ known-bug: #NNN`.
+- The already-fixed ICEs in the archived [Glacier][glacier] repository --- though
+  avoid the unfixed ones in `ices/`!
+
+[glacier]: https://github.com/rust-lang/glacier
 
 ## Extra credit
 
 Here are a few things you can do to help the Rust project after filing an ICE.
 
-- [Bisect][bisect] the bug to figure out when it was introduced 
+- [Bisect][bisect] the bug to figure out when it was introduced.
+  If you find the regressing PR / commit, you can mark the issue with the label
+  `S-has-bisection`. If not, consider applying `E-needs-bisection` instead.
 - Fix "distractions": problems with the test case that don't contribute to
   triggering the ICE, such as syntax errors or borrow-checking errors
-- Minimize the test case (see below)
-- Add the minimal test case to [Glacier][glacier]
+- Minimize the test case (see below). If successful, you can label the
+  issue with `S-has-mcve`. Otherwise, you can apply `E-needs-mcve`.
+- Add the minimal test case to the rust-lang/rust repo as a [crashes test].
+  While you're at it, consider including other "untracked" crashes in your PR.
+  Please don't forget to mark your issue with `S-bug-has-test` afterwards.
+
+See also [applying and removing labels][labeling].
 
 [bisect]: https://rust-lang.github.io/cargo-bisect-rustc/
+[crashes test]: tests/compiletest.html#crashes-tests
+[labeling]: https://forge.rust-lang.org/release/issue-triaging.html#applying-and-removing-labels
 
 ## Minimization
 
@@ -143,7 +154,6 @@ ICEs that require debug assertions to reproduce should be tagged
 - [tree-splicer][tree-splicer] generates new source files by combining existing
   ones while maintaining correct syntax
 
-[glacier]: https://github.com/rust-lang/glacier
 [fuzz-rustc]: https://github.com/dwrensha/fuzz-rustc
 [icemaker]: https://github.com/matthiaskrgr/icemaker/
 [tree-splicer]: https://github.com/langston-barrett/tree-splicer/

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

@@ -89,7 +89,7 @@ filtering the search to areas you're interested in. For example:
 Not all important or beginner work has issue labels.
 See below for how to find work that isn't labelled.
 
-[help-wanted-search]: https://github.com/issues?q=is%3Aopen+is%3Aissue+org%3Arust-lang+no%3Aassignee+label%3AE-easy%2C%22good+first+issue%22%2Cgood-first-issue%2CE-medium%2CEasy%2CE-help-wanted%2CE-mentor+-label%3AS-blocked+-linked:pr+
+[help-wanted-search]: https://github.com/issues?q=is%3Aopen+is%3Aissue+org%3Arust-lang+no%3Aassignee+label%3AE-easy%2C%22good+first+issue%22%2Cgood-first-issue%2CE-medium%2CEasy%2CE-help-wanted%2CE-mentor+-label%3AS-blocked+-linked%3Apr+
 [Triage]: ./contributing.md#issue-triage
 
 ### Recurring work
@@ -98,8 +98,6 @@ Some work is too large to be done by a single person. In this case, it's common
 issues" to co-ordinate the work between contributors. Here are some example tracking issues where
 it's easy to pick up work without a large time commitment:
 
-- [Rustdoc Askama Migration](https://github.com/rust-lang/rust/issues/108868)
-- [Diagnostic Translation](https://github.com/rust-lang/rust/issues/100717)
 - [Move UI tests to subdirectories](https://github.com/rust-lang/rust/issues/73494)
 
 If you find more recurring work, please feel free to add it here!