Auto merge of #141506 - matthiaskrgr:rollup-80f1geg, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #137323 (Guarantee behavior of transmuting `Option::<T>::None` subject to NPO)
 - #139254 (std: sys: net: uefi: Implement TCP4 connect)
 - #141432 (refactor `CanonicalVarKind`)
 - #141480 (document some -Z flags as living in the rustc-dev-guide)
 - #141486 (rustdoc book: add argument explanation for `html_playground_url`)
 - #141496 (Enable `[issue-links]` and `[no-mentions]` in triagebot)

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

4 files changed, 40 insertions, 2 deletions

diff --git a/src/doc/rustdoc/src/write-documentation/the-doc-attribute.md b/src/doc/rustdoc/src/write-documentation/the-doc-attribute.md
index 45146993371..6ec93d1746c 100644
--- a/src/doc/rustdoc/src/write-documentation/the-doc-attribute.md
+++ b/src/doc/rustdoc/src/write-documentation/the-doc-attribute.md
@@ -88,8 +88,10 @@ on your documentation examples make requests to.
 ```
 
 Now, when you press "run", the button will make a request to this domain. The request
-URL will contain 2 query parameters: `code` and `edition` for the code in the documentation
-and the Rust edition respectively.
+URL will contain 3 query parameters:
+1. `code` for the code in the documentation
+2. `version` for the Rust channel, e.g. nightly, which is decided by whether `code` contain unstable features
+3. `edition` for the Rust edition, e.g. 2024
 
 If you don't use this attribute, there will be no run buttons.
 
diff --git a/src/doc/unstable-book/src/compiler-flags/eagerly-emit-delayed-bugs.md b/src/doc/unstable-book/src/compiler-flags/eagerly-emit-delayed-bugs.md
new file mode 100644
index 00000000000..39f0c04a1b5
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/eagerly-emit-delayed-bugs.md
@@ -0,0 +1,12 @@
+# `eagerly-emit-delayed-bugs`
+
+This feature is perma-unstable and has no tracking issue.
+
+------------------------
+
+This flag converts all [`span_delayed_bug()`] calls to [`bug!`] calls, exiting the compiler immediately and allowing you to generate a backtrace of where the delayed bug occurred.
+For full documentation, see [the rustc-dev-guide][dev-guide-delayed].
+
+[`bug!`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/macro.bug.html
+[`span_delayed_bug()`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.DiagCtxtHandle.html#method.span_delayed_bug
+[dev-guide-delayed]: https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#debugging-delayed-bugs
diff --git a/src/doc/unstable-book/src/compiler-flags/track-diagnostics.md b/src/doc/unstable-book/src/compiler-flags/track-diagnostics.md
new file mode 100644
index 00000000000..48620214407
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/track-diagnostics.md
@@ -0,0 +1,11 @@
+# `track-diagnostics`
+
+This feature is perma-unstable and has no tracking issue.
+
+------------------------
+
+This flag prints the source code span in the compiler where a diagnostic was generated, respecting [`#[track_caller]`][track_caller]. Note that this may be different from the place it was emitted.
+For full documentation, see [the rustc-dev-guide][dev-guide-track-diagnostics].
+
+[track_caller]: https://doc.rust-lang.org/reference/attributes/codegen.html#the-track_caller-attribute
+[dev-guide-track-diagnostics]: https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#getting-the-error-creation-location
diff --git a/src/doc/unstable-book/src/compiler-flags/treat-err-as-bug.md b/src/doc/unstable-book/src/compiler-flags/treat-err-as-bug.md
new file mode 100644
index 00000000000..df7c380a50b
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/treat-err-as-bug.md
@@ -0,0 +1,13 @@
+# `treat-err-as-bug`
+
+This feature is perma-unstable and has no tracking issue.
+
+------------------------
+
+This flag converts the selected error to a [`bug!`] call, exiting the compiler immediately and allowing you to generate a backtrace of where the error occurred.
+For full documentation, see [the rustc-dev-guide][dev-guide-backtrace].
+
+Note that the compiler automatically sets `RUST_BACKTRACE=1` for itself, and so you do not need to set it yourself when using this flag.
+
+[`bug!`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/macro.bug.html
+[dev-guide-backtrace]: https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#getting-a-backtrace-for-errors