Merge pull request #20243 from lnicola/sync-from-rust

minor: Sync from downstream

Author: lnicola

josh-sync.toml

@@ -0,0 +1,3 @@
+org = "rust-lang"
+repo = "rustc-dev-guide"
+path = "src/doc/rustc-dev-guide"

rust-version

@@ -1 +1 @@
-d1d8e386c5e84c4ba857f56c3291f73c27e2d62a
+c96a69059ecc618b519da385a6ccd03155aa0237

src/autodiff/internals.md

@@ -2,11 +2,11 @@ The `std::autodiff` module in Rust allows differentiable programming:
 
 ```rust
 #![feature(autodiff)]
-use std::autodiff::autodiff;
+use std::autodiff::*;
 
 // f(x) = x * x, f'(x) = 2.0 * x
 // bar therefore returns (x * x, 2.0 * x)
-#[autodiff(bar, Reverse, Active, Active)]
+#[autodiff_reverse(bar, Active, Active)]
 fn foo(x: f32) -> f32 { x * x }
 
 fn main() {

src/building/bootstrapping/debugging-bootstrap.md

@@ -168,10 +168,17 @@ For `#[instrument]`, it's recommended to:
 
 ### Profiling bootstrap
 
-You can use the `COMMAND` tracing target to trace execution of most commands spawned by bootstrap. If you also use the `BOOTSTRAP_PROFILE=1` environment variable, bootstrap will generate a Chrome JSON trace file, which can be visualized in Chrome's `chrome://tracing` page or on https://ui.perfetto.dev.
+You can set the `BOOTSTRAP_PROFILE=1` environment variable to enable command execution profiling during bootstrap. This generates:
+
+* A Chrome trace file (for visualization in `chrome://tracing` or [Perfetto](https://ui.perfetto.dev)) if tracing is enabled via `BOOTSTRAP_TRACING=COMMAND=trace`
+* A plain-text summary file, `bootstrap-profile-{pid}.txt`, listing all commands sorted by execution time (slowest first), along with cache hits and working directories
+
+Note: the `.txt` report is always generated when `BOOTSTRAP_PROFILE=1` is set — tracing is not required.
+
+Example usage:
 
 ```bash
-$ BOOTSTRAP_TRACING=COMMAND=trace BOOTSTRAP_PROFILE=1 ./x build library
+$ BOOTSTRAP_PROFILE=1 BOOTSTRAP_TRACING=COMMAND=trace ./x build library
 ```
 
 ### rust-analyzer integration?

src/building/how-to-build-and-run.md

@@ -2,6 +2,24 @@
 
 <!-- toc -->
 
+<div class="warning">
+
+For `profile = "library"` users, or users who use `download-rustc = true | "if-unchanged"`, please be advised that
+the `./x test library/std` flow where `download-rustc` is active (i.e. no compiler changes) is currently broken.
+This is tracked in <https://github.com/rust-lang/rust/issues/142505>. Only the `./x test` flow is affected in this
+case, `./x {check,build} library/std` should still work.
+
+In the short-term, you may need to disable `download-rustc` for `./x test library/std`. This can be done either by:
+
+1. `./x test library/std --set rust.download-rustc=false`
+2. Or set `rust.download-rustc=false` in `bootstrap.toml`.
+
+Unfortunately that will require building the stage 1 compiler. The bootstrap team is working on this, but
+implementing a maintainable fix is taking some time.
+
+</div>
+
+
 The compiler is built using a tool called `x.py`. You will need to
 have Python installed to run it.
 

src/contributing.md

@@ -434,6 +434,10 @@ Just a few things to keep in mind:
   it might benefit from having a Table of Contents at the beginning,
   which you can auto-generate by including the `<!-- toc -->` marker at the top.
 
+#### ⚠️ Note: Where to contribute `rustc-dev-guide` changes
+
+For detailed information about where to contribute rustc-dev-guide changes and the benefits of doing so, see [the rustc-dev-guide working group documentation](https://forge.rust-lang.org/wg-rustc-dev-guide/index.html#where-to-contribute-rustc-dev-guide-changes).
+
 ## Issue triage
 
 Please see <https://forge.rust-lang.org/release/issue-triaging.html>.

src/diagnostics/diagnostic-structs.md

@@ -1,14 +1,18 @@
 # Diagnostic and subdiagnostic structs
 rustc has three diagnostic traits that can be used to create diagnostics:
-`Diagnostic`, `LintDiagnostic`, and `Subdiagnostic`. For simple diagnostics,
-instead of using the `Diag` API to create and emit diagnostics,
-derived impls can be used. They are only suitable for simple diagnostics that
+`Diagnostic`, `LintDiagnostic`, and `Subdiagnostic`.
+
+For simple diagnostics,
+derived impls can be used, e.g. `#[derive(Diagnostic)]`. They are only suitable for simple diagnostics that
 don't require much logic in deciding whether or not to add additional
 subdiagnostics.
 
-Such diagnostic can be translated into
-different languages and each has a slug that uniquely identifies the
-diagnostic.
+In cases where diagnostics require more complex or dynamic behavior, such as conditionally adding subdiagnostics,
+customizing the rendering logic, or selecting messages at runtime, you will need to manually implement
+the corresponding trait (`Diagnostic`, `LintDiagnostic`, or `Subdiagnostic`).
+This approach provides greater flexibility and is recommended for diagnostics that go beyond simple, static structures.
+
+Diagnostic can be translated into different languages and each has a slug that uniquely identifies the diagnostic.
 
 ## `#[derive(Diagnostic)]` and `#[derive(LintDiagnostic)]`
 
@@ -142,7 +146,7 @@ tcx.dcx().emit_err(FieldAlreadyDeclared {
 });
 ```
 
-### Reference
+### Reference for `#[derive(Diagnostic)]` and `#[derive(LintDiagnostic)]`
 `#[derive(Diagnostic)]` and `#[derive(LintDiagnostic)]` support the
 following attributes:
 
@@ -330,7 +334,34 @@ function ([example][subdiag_use_1] and [example][subdiag_use_2]) on a
 diagnostic or by assigning it to a `#[subdiagnostic]`-annotated field of a
 diagnostic struct.
 
-### Reference
+### Argument sharing and isolation
+
+Subdiagnostics add their own arguments (i.e., certain fields in their structure) to the `Diag` structure before rendering the information.
+`Diag` structure also stores the arguments from the main diagnostic, so the subdiagnostic can also use the arguments from the main diagnostic.
+
+However, when a subdiagnostic is added to a main diagnostic by implementing `#[derive(Subdiagnostic)]`,
+the following rules, introduced in [rust-lang/rust#142724](https://github.com/rust-lang/rust/pull/142724)
+apply to the handling of arguments (i.e., variables used in Fluent messages):
+
+**Argument isolation between sub diagnostics**:
+Arguments set by a subdiagnostic are only available during the rendering of that subdiagnostic.
+After the subdiagnostic is rendered, all arguments it introduced are restored from the main diagnostic.
+This ensures that multiple subdiagnostics do not pollute each other's argument scope.
+For example, when using a `Vec<Subdiag>`, it iteratively adds the same argument over and over again.
+
+**Same argument override between sub and main diagnostics**:
+If a subdiagnostic sets a argument with the same name as a arguments already in the main diagnostic,
+it will report an error at runtime unless both have exactly the same value.
+It has two benefits:
+- preserves the flexibility that arguments in the main diagnostic are allowed to appear in the attributes of the subdiagnostic.
+For example, There is an attribute `#[suggestion(code = "{new_vis}")]` in the subdiagnostic, but `new_vis` is the field in the main diagnostic struct.
+- prevents accidental overwriting or deletion of arguments required by the main diagnostic or other subdiagnostics.
+
+These rules guarantee that arguments injected by subdiagnostics are strictly scoped to their own rendering.
+The main diagnostic's arguments remain unaffected by subdiagnostic logic, even in the presence of name collisions.
+Additionally, subdiagnostics can access arguments from the main diagnostic with the same name when needed.
+
+### Reference for `#[derive(Subdiagnostic)]`
 `#[derive(Subdiagnostic)]` supports the following attributes:
 
 - `#[label(slug)]`, `#[help(slug)]`, `#[warning(slug)]` or `#[note(slug)]`

src/hir/lowering.md

@@ -7,10 +7,8 @@ of such structures include but are not limited to
 
 * Parenthesis
     * Removed without replacement, the tree structure makes order explicit
-* `for` loops and `while (let)` loops
-    * Converted to `loop` + `match` and some `let` bindings
-* `if let`
-    * Converted to `match`
+* `for` loops
+    * Converted to `match` + `loop` + `match`
 * Universal `impl Trait`
     * Converted to generic arguments
       (but with some flags, to know that the user didn't write them)

src/rustdoc-internals/rustdoc-test-suite.md

@@ -55,6 +55,9 @@ Similar to shell commands,
 directives can extend across multiple lines if their last char is `\`.
 In this case, the start of the next line should be `//`, with no `@`.
 
+Similar to compiletest directives, besides a space you can also use a colon `:` to separate
+the directive name and the arguments, however a space is preferred for HtmlDocCk directives.
+
 Use the special string `{{channel}}` in XPaths, `PATTERN` arguments and [snapshot files](#snapshot)
 if you'd like to refer to the URL `https://doc.rust-lang.org/CHANNEL` where `CHANNEL` refers to the
 current release channel (e.g, `stable` or `nightly`).

src/solve/opaque-types.md

@@ -56,7 +56,7 @@ Finally, we check whether the item bounds of the opaque hold for the expected ty
 [source][item-bounds-ck].
 
 [norm]: https://github.com/rust-lang/rust/blob/384d26fc7e3bdd7687cc17b2662b091f6017ec2a/compiler/rustc_trait_selection/src/solve/normalizes_to/opaque_types.rs#L13
-[coherence-example]: https://github.com/rust-lang/rust/blob/master/tests/ui/type-alias-impl-trait/coherence_different_hidden_ty.rs
+[coherence-example]: https://github.com/rust-lang/rust/blob/master/tests/ui/type-alias-impl-trait/coherence/coherence_different_hidden_ty.rs
 [placeholder-ck]: https://github.com/rust-lang/rust/blob/384d26fc7e3bdd7687cc17b2662b091f6017ec2a/compiler/rustc_trait_selection/src/solve/normalizes_to/opaque_types.rs#L33
 [check-storage]: https://github.com/rust-lang/rust/blob/384d26fc7e3bdd7687cc17b2662b091f6017ec2a/compiler/rustc_trait_selection/src/solve/normalizes_to/opaque_types.rs#L51-L52
 [eq-prev]: https://github.com/rust-lang/rust/blob/384d26fc7e3bdd7687cc17b2662b091f6017ec2a/compiler/rustc_trait_selection/src/solve/normalizes_to/opaque_types.rs#L51-L59