Auto merge of #138595 - jhpratt:rollup-09pvfzu, r=jhpratt

Rollup of 9 pull requests

Successful merges:

 - #136355 (Add `*_value` methods to proc_macro lib)
 - #137621 (Add std support to cygwin target)
 - #137793 (Stablize anonymous pipe)
 - #138341 (std: Mention clone-on-write mutation in Arc<T>)
 - #138517 (Improve upvar analysis for deref of child capture)
 - #138584 (Update Rust Foundation links in Readme)
 - #138586 (Document `#![register_tool]`)
 - #138590 (Flatten and simplify some control flow 🫓)
 - #138592 (update change entry for #137147)

r? `@ghost`
`@rustbot` modify labels: rollup

8 files changed, 66 insertions, 6 deletions

diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index b062781e68a..343fbcc0286 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -655,7 +655,7 @@ mod dist {
         let mut builder = Builder::new(&build);
         builder.run_step_descriptions(
             &Builder::get_step_descriptions(Kind::Build),
-            &["compiler/rustc".into(), "library".into()],
+            &["compiler/rustc".into(), "std".into()],
         );
 
         assert_eq!(builder.config.stage, 2);
diff --git a/src/bootstrap/src/core/metadata.rs b/src/bootstrap/src/core/metadata.rs
index 2706aba5ffc..3720602dc77 100644
--- a/src/bootstrap/src/core/metadata.rs
+++ b/src/bootstrap/src/core/metadata.rs
@@ -62,6 +62,11 @@ pub fn build(build: &mut Build) {
             let relative_path = krate.local_path(build);
             build.crates.insert(name.clone(), krate);
             let existing_path = build.crate_paths.insert(relative_path, name);
+            // `literal-escaper` is both a dependency of `compiler/rustc_lexer` and of
+            // `library/proc-macro`, making it appear multiple times in the workspace.
+            if existing_path.as_deref() == Some("literal-escaper") {
+                continue;
+            }
             assert!(
                 existing_path.is_none(),
                 "multiple crates with the same path: {}",
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 91574f8bf5d..2cf613c4d4a 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -716,7 +716,7 @@ impl Build {
             features.push("llvm");
         }
         // keep in sync with `bootstrap/compile.rs:rustc_cargo_env`
-        if self.config.rust_randomize_layout {
+        if self.config.rust_randomize_layout && check("rustc_randomized_layouts") {
             features.push("rustc_randomized_layouts");
         }
 
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index f8478725c4c..f2fae9862d3 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -383,6 +383,6 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
     ChangeInfo {
         change_id: 137147,
         severity: ChangeSeverity::Info,
-        summary: "New option `build.exclude` that adds support for excluding test.",
+        summary: "Added new option `build.exclude` which works the same way as `--exclude` flag on `x`.",
     },
 ];
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index d9587297e79..058b0b0a07a 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -407,7 +407,7 @@ target | std | host | notes
 [`wasm32-wali-linux-musl`](platform-support/wasm32-wali-linux.md) | ? |  | WebAssembly with [WALI](https://github.com/arjunr2/WALI)
 [`x86_64-apple-tvos`](platform-support/apple-tvos.md) | ✓ |  | x86 64-bit tvOS
 [`x86_64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ |  | x86 64-bit Apple WatchOS simulator
-[`x86_64-pc-cygwin`](platform-support/x86_64-pc-cygwin.md) | ? |  | 64-bit x86 Cygwin |
+[`x86_64-pc-cygwin`](platform-support/x86_64-pc-cygwin.md) | ✓ |  | 64-bit x86 Cygwin |
 [`x86_64-pc-nto-qnx710`](platform-support/nto-qnx.md) | ✓ |  | x86 64-bit QNX Neutrino 7.1 RTOS with default network stack (io-pkt) |
 [`x86_64-pc-nto-qnx710_iosock`](platform-support/nto-qnx.md) | ✓ |  | x86 64-bit QNX Neutrino 7.1 RTOS with new network stack (io-sock) |
 [`x86_64-pc-nto-qnx800`](platform-support/nto-qnx.md) | ✓ |  | x86 64-bit QNX Neutrino 8.0 RTOS |
diff --git a/src/doc/unstable-book/src/language-features/register-tool.md b/src/doc/unstable-book/src/language-features/register-tool.md
new file mode 100644
index 00000000000..58b923aab57
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/register-tool.md
@@ -0,0 +1,55 @@
+# `register_tool`
+
+The tracking issue for this feature is: [#66079]
+
+[#66079]: https://github.com/rust-lang/rust/issues/66079
+
+------------------------
+
+The `register_tool` language feature informs the compiler that attributes in your code are meant to be used with tools other than the compiler itself. This can be useful if your code has semantic meaning without the external tool, but enables additional features when the tool is present.
+
+`register_tool` also allows configuring lint levels for external tools.
+
+Tool attributes are only meant for ignorable attributes. If your code *changes* meaning when the attribute is present, it should not use a tool attribute (because it cannot be compiled with anything other than the external tool, and in a sense is a fork of the language).
+
+------------------------
+
+`#![register_tool(tool)]` is an attribute, and is only valid at the crate root.
+Attributes using the registered tool are checked for valid syntax, and lint attributes are checked to be in a valid format. However, the compiler cannot validate the semantics of the attribute, nor can it tell whether the configured lint is present in the external tool.
+
+Semantically, `clippy::*`, `rustdoc::*`, and `rustfmt::*` lints and attributes all behave as if `#![register_tool(clippy, rustdoc, rustfmt)]` were injected into the crate root, except that the `rustdoc` namespace can only be used for lints, not for attributes.
+When compiling with `-Z unstable-features`, `rustc::*` lints can also be used. Like `rustdoc`, the `rustc` namespace can only be used with lints, not attributes.
+
+The compiler will emit an error if it encounters a lint/attribute whose namespace isn't a registered tool.
+
+Tool namespaces cannot be nested; `register_tool(main_tool::subtool)` is an error.
+
+## Examples
+
+Tool attributes:
+
+```rust
+#![feature(register_tool)]
+#![register_tool(c2rust)]
+
+// Mark which C header file this module was generated from.
+#[c2rust::header_src = "operations.h"]
+pub mod operations_h {
+    use std::ffi::c_int;
+
+    // Mark which source line this struct was generated from.
+    #[c2rust::src_loc = "11:0"]
+    pub struct Point {
+        pub x: c_int,
+        pub y: c_int,
+    }
+}
+```
+
+Tool lints:
+
+```
+#![feature(register_tool)]
+#![register_tool(bevy)]
+#![deny(bevy::duplicate_bevy_dependencies)]
+```
diff --git a/src/tools/miri/tests/pass/shims/pipe.rs b/src/tools/miri/tests/pass/shims/pipe.rs
index 1be29886d2d..c47feb8774a 100644
--- a/src/tools/miri/tests/pass/shims/pipe.rs
+++ b/src/tools/miri/tests/pass/shims/pipe.rs
@@ -1,7 +1,5 @@
 //@ignore-target: windows
 
-#![feature(anonymous_pipe)]
-
 use std::io::{Read, Write, pipe};
 
 fn main() {
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 81c55ecaa7a..8a95c6dd5e6 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -318,6 +318,7 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "libloading",
     "linux-raw-sys",
     "litemap",
+    "literal-escaper",
     "lock_api",
     "log",
     "matchers",
@@ -363,6 +364,7 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "rustc-rayon",
     "rustc-rayon-core",
     "rustc-stable-hash",
+    "rustc-std-workspace-std",
     "rustc_apfloat",
     "rustix",
     "ruzstd", // via object in thorin-dwp