prepares 421 for publish, adds draft for 422

Signed-off-by: Nell Shamrell <[email protected]>

Author: nellshamrell

draft/2021-12-15-this-week-in-rust.md renamed to content/2021-12-15-this-week-in-rust.md

@@ -0,0 +1,195 @@
+Title: This Week in Rust 422
+Number: 422
+Date: 2021-12-22
+Category: This Week in Rust
+
+Hello and welcome to another issue of *This Week in Rust*!
+[Rust](http://rust-lang.org) is a programming language empowering everyone to build reliable and efficient software.
+This is a weekly summary of its progress and community.
+Want something mentioned? Tweet us at [@ThisWeekInRust](https://twitter.com/ThisWeekInRust) or [send us a pull request](https://github.com/rust-lang/this-week-in-rust).
+Want to get involved? [We love contributions](https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md).
+
+*This Week in Rust* is openly developed [on GitHub](https://github.com/rust-lang/this-week-in-rust).
+If you find any errors in this week's issue, [please submit a PR](https://github.com/rust-lang/this-week-in-rust/pulls).
+
+## Updates from Rust Community
+
+### Official
+
+### Foundation
+
+### Newsletters
+
+### Project/Tooling Updates
+
+### Observations/Thoughts
+
+### Rust Walkthroughs
+
+### Miscellaneous
+
+## Crate of the Week
+
+This week's crate is [efg](https://crates.io/crates/efg), a proc macro to allow boolean expression like syntax for `#[cfg]`s.
+
+Thanks to [farnbams](https://users.rust-lang.org/t/crate-of-the-week/2704/991) for the suggestion!
+
+[Please submit your suggestions and votes for next week][submit_crate]!
+
+[submit_crate]: https://users.rust-lang.org/t/crate-of-the-week/2704
+
+## Call for Participation
+
+Always wanted to contribute to open-source projects but didn't know where to start?
+Every week we highlight some tasks from the Rust community for you to pick and get started!
+
+Some of these tasks may also have mentors available, visit the task page for more information.
+
+If you are a Rust project owner and are looking for contributors, please submit tasks [here][guidelines].
+
+[guidelines]: https://users.rust-lang.org/t/twir-call-for-participation/4821
+
+## Updates from the Rust Project
+
+315 pull requests were [merged in the last week][merged]
+
+[merged]: https://github.com/search?q=is%3Apr+org%3Arust-lang+is%3Amerged+merged%3A2021-12-06..2021-12-13
+
+* [asm: allow using r9 (ARM) and x18 (AArch64) if they are not reserved by the current target](https://github.com/rust-lang/rust/pull/91643)
+* [suggest using a temporary variable to fix borrowck errors](https://github.com/rust-lang/rust/pull/83174)
+* [tweak "call this function" suggestion to have smaller span](https://github.com/rust-lang/rust/pull/91503)
+* [tweak assoc type obligation spans](https://github.com/rust-lang/rust/pull/91769)
+* [better span for unexpected normalization failure in CTFE engine](https://github.com/rust-lang/rust/pull/91815)
+* [give more help in the unaligned_references lint](https://github.com/rust-lang/rust/pull/91718)
+* [suggest casting between `i`/`u32` and `char`](https://github.com/rust-lang/rust/pull/91245)
+* [add a suggestion if `macro_rules` is misspelled](https://github.com/rust-lang/rust/pull/91337)
+* [avoid cloning refcounted types during folding](https://github.com/rust-lang/rust/pull/91353)
+* [deduplicate projection sub-obligations](https://github.com/rust-lang/rust/pull/90423)
+* [do not ICE when suggesting elided lifetimes on non-existent spans](https://github.com/rust-lang/rust/pull/91764)
+* [do not add `;` to expected tokens list when it's wrong](https://github.com/rust-lang/rust/pull/91531)
+* [do not attempt to suggest help for overly malformed struct/function call](https://github.com/rust-lang/rust/pull/91634)
+* [improve 'cannot contain emoji' error](https://github.com/rust-lang/rust/pull/91476)
+* [add `spin_loop` hint for RISC-V architecture](https://github.com/rust-lang/rust/pull/91548)
+* [override `Iterator::advance`(`_back`)`_by` for `array::IntoIter`](https://github.com/rust-lang/rust/pull/91512)
+* [replace dominators algorithm with simple Lengauer-Tarjan](https://github.com/rust-lang/rust/pull/85013)
+* [add `<*{const|mut} T>::{to|from}_bits`](https://github.com/rust-lang/rust/pull/91127)
+* [add `array::IntoIter::`{`empty`, `from_raw_parts`}](https://github.com/rust-lang/rust/pull/91341)
+* [add `rsplit_array` variants to slices and arrays](https://github.com/rust-lang/rust/pull/91515)
+* [make `Option::cloned` `const`](https://github.com/rust-lang/rust/pull/90741)
+* [make `(*mut T)::write_bytes` `const`](https://github.com/rust-lang/rust/pull/91824)
+* [make `Borrow` and `BorrowMut` impls `const`](https://github.com/rust-lang/rust/pull/90270)
+* [make `Unique`s methods `const`](https://github.com/rust-lang/rust/pull/91806)
+* [make `intrinsics::write_bytes` `const`](https://github.com/rust-lang/rust/pull/90081)
+* [implement `TryFrom<&'_ mut [T]>` for `[T; N]`](https://github.com/rust-lang/rust/pull/91086)
+* [implement `core::future::join!`](https://github.com/rust-lang/rust/pull/91645)
+* [implement concat_bytes!](https://github.com/rust-lang/rust/pull/87599)
+* [provide the `ReadBuf` abstraction](https://github.com/rust-lang/rust/pull/81156)
+* [stabilise `feature(const_generics_defaults)`](https://github.com/rust-lang/rust/pull/90207)
+* [stabilize `ControlFlow::`{`is_break`, `is_continue`}](https://github.com/rust-lang/rust/pull/91091)
+* [stabilize `const_cstr_unchecked`](https://github.com/rust-lang/rust/pull/91855)
+* [cargo: improve I/O error message for fingerprint of build script](https://github.com/rust-lang/cargo/pull/10191)
+* [rustdoc: show type layout for type aliases](https://github.com/rust-lang/rust/pull/91682)
+* [clippy: add new lint to warn when `#[must_use]` attribute should be used on a method](https://github.com/rust-lang/rust-clippy/pull/8071)
+* [clippy: fix FP on `question_mark` if returned object is not local](https://github.com/rust-lang/rust-clippy/pull/8080)
+* [clippy: fix `blocks_in_if_conditions` false positive](https://github.com/rust-lang/rust-clippy/pull/8100)
+* [clippy: fix bad suggestion on `option_if_let_else` when there is complex subpat](https://github.com/rust-lang/rust-clippy/pull/8086)
+* [clippy: ignore associated types in traits when considering type complexity](https://github.com/rust-lang/rust-clippy/pull/8030)
+
+### Rust Compiler Performance Triage
+
+This week's report started with 6 regressions; after eliminating truly obvious noise, we are left with just 2 minor regressions. Of the cases that regressed, I think the only interesting one is keccak (regressed by 1.73% in PR #91549). But don't be too depressed: keccak was also improved up to 23% by PR #85013 (!); thanks to @**simulacrum** for that PR.
+
+Triage done by **@pnkfelix**.
+Revision range: [e2116a..404c847](https://perf.rust-lang.org/?start=e2116acae59654bfab2a9729a024f3e2fd6d4b02&end=404c8471aba60c2d837fa728e7c729a0f52d5830&absolute=false&stat=instructions%3Au)
+
+2 Regressions, 5 Improvements, 3 Mixed; 1 of them in rollups
+48 comparisons made in total
+
+[Full report here](https://github.com/rust-lang/rustc-perf/blob/master/triage/2021-12-14.md)
+
+### [Approved RFCs](https://github.com/rust-lang/rfcs/commits/master)
+
+Changes to Rust follow the Rust [RFC (request for comments) process](https://github.com/rust-lang/rfcs#rust-rfcs). These
+are the RFCs that were approved for implementation this week:
+
+* *No RFCs were approved this week.*
+
+### Final Comment Period
+
+Every week [the team](https://www.rust-lang.org/team.html) announces the
+'final comment period' for RFCs and key PRs which are reaching a
+decision. Express your opinions now.
+
+#### [RFCs](https://github.com/rust-lang/rfcs/labels/final-comment-period)
+
+* [disposition: merge] [Amend RFC 2996 to replace Stream with AsyncIterator](https://github.com/rust-lang/rfcs/pull/3208)
+* [disposition: merge] [Thread local Cell methods.](https://github.com/rust-lang/rfcs/pull/3184)
+
+#### [Tracking Issues & PRs](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3Afinal-comment-period+sort%3Aupdated-desc)
+
+* [disposition: merge] [Make rustdoc --passes and rustdoc --no-defaults have no effect](https://github.com/rust-lang/rust/issues/91714)
+* [disposition: merge] [make Instant::{duration_since, elapsed, sub} saturating and remove workarounds](https://github.com/rust-lang/rust/pull/89926)
+* [disposition: close] [Tracking issue for RFC 2115: In-band lifetime bindings](https://github.com/rust-lang/rust/issues/44524)
+
+### [New RFCs](https://github.com/rust-lang/rfcs/pulls)
+
+* *No new RFCs were published this week.*
+
+## Upcoming Events
+
+Rusty Events between 12/15/2021 - 1/15/2022 🦀
+
+### Online
+
+* [December 15, 2021 | Cardiff, UK | **Rust Book Study Session - Error Handling & Generic Types, Traits, and Lifetimes** | Rust and C++ Cardiff](https://www.meetup.com/rust-and-c-plus-plus-in-cardiff/events/282313169/)
+* [December 16, 2021 | Linz, AT | **Rust Meetup Linz - 17th Edition** | Rust Linz](https://www.meetup.com/Rust-Linz/events/282559064/)
+* [December 17, 2021 | Various cities, IR | **The Third Rust Iran online meetup** | Rust Iran Meetup](https://rust-meetup.ir)
+* [December 18, 2021 | Vancouver, BC, CA | **Your Rust Web Development Toolset** | Vancouver Rust](https://www.meetup.com/Vancouver-Rust/events/nwcmpsyccqbtb/)
+* [December 21, 2021 | Los Gatos, CA, US | **Book #24 - Rust for Rustaceans - Chapter 1 (session 3)** | Los Gatos Reading Group](https://www.meetup.com/Los-Gatos-Rust-Reading-Group/events/282687733/) | [Alternative Link (South Padre Island, TX Reading Group)](https://www.meetup.com/the-south-padre-island-reading-group/events/282687761/)
+* [December 21, 2021 | Washington, DC, US | **Mid-month Rustful** | Rust DC](https://www.meetup.com/RustDC/events/vdhxgsyccqbcc/)
+* [December 23, 2021 | Stuttgart, DE | **Rust-Meetup** | Rust Community Stuttgart](https://www.meetup.com/Rust-Community-Stuttgart/events/ttjjqsyccqbfc/)
+* [December 28, 2021 | Dallas, TX, US | **Dallas Rust - Last Tuesday** | Dallas Rust](https://www.meetup.com/Dallas-Rust/events/jqxqwryccqblc/)
+* [January 5, 2022 | Indianapolis, IN, US | **Indy.rs - with Social Distancing** | Indy Rust](https://www.meetup.com/indyrs/events/qwtdjsydccbhb/)
+* [January 6, 2022 | Nürnberg, DE | **Rust Nürnberg online #8**| Rust Nuremberg](https://www.meetup.com/rust-noris/events/282344613/)
+* [January 8, 2022 | Various cities | **Rust GameDev Monthly Meetup** | Rust GameDev](https://www.google.com/calendar/embed?src=apd9vmbc22egenmtu5l6c5jbfc%40group.calendar.google.com)
+* [January 11, 2022 | Seattle, WA, US | **Monthly meetup** | Seattle Rust Meetup](https://www.meetup.com/Seattle-Rust-Meetup/events/gskksrydccbpb/)
+* [January 12, 2022 | Boulder, CO, US | **Monthly Meetup** | Boulder Elixir and Rust](https://www.meetup.com/boulder-elixir-rust/events/zvxcsrydccbqb/)
+* [January 12, 2022 | Los Angeles, CA, US | **Live Coding Session - Mob Programming a Rust Code Kata [Virtual] Jan. 2022** | Rust Los Angeles](https://www.meetup.com/Rust-Los-Angeles/events/282580016/)
+* [January 12, 2022 | Stuttgart, DE | **Rust-Meetup** | Rust Community Stuttgart](https://www.meetup.com/Rust-Community-Stuttgart/events/gjrtqsydccbqb/)
+
+
+### North America
+
+* [December 16, 2021 | Austin, TX, US | **Rust Lunch** | Rust ATX](https://www.meetup.com/rust-atx/events/282472182)
+* [January 12, 2022 | Atlanta, GA, US | **Grab a beer with fellow Rustaceans** | Rust Atlanta](https://www.meetup.com/Rust-ATL/events/lhpkmsydccbqb/)
+* [January 13, 2022 | Columbus, OH, US | **Monthly Meeting** | Columbus Rust Society](https://www.meetup.com/columbus-rs/events/dpkhgrydccbrb/)
+
+
+If you are running a Rust event please add it to the [calendar] to get
+it mentioned here. Please remember to add a link to the event too.
+Email the [Rust Community Team][community] for access.
+
+[calendar]: https://www.google.com/calendar/embed?src=apd9vmbc22egenmtu5l6c5jbfc%40group.calendar.google.com
+[community]: mailto:[email protected]
+
+# Rust Jobs
+
+*Tweet us at [@ThisWeekInRust](https://twitter.com/ThisWeekInRust) to get your job offers listed here!*
+
+# Quote of the Week
+
+> This is safer than you may think, because those who need async tend to know it themselves and
+> don't ask "should I use async" question. In other words, asking itself is a signal that answer is
+> no. MITM proxy case was a rare exception.
+
+– [Seo Sanghyeon on rust-users](https://users.rust-lang.org/t/examples-of-high-performance-rust-multi-thread-network-app-w-o-async/68513/4)
+
+Thanks to [Zeroexcuses](https://users.rust-lang.org/t/twir-quote-of-the-week/328/1146) for the suggestion!
+
+[Please submit quotes and vote for next week!](https://users.rust-lang.org/t/twir-quote-of-the-week/328)
+
+*This Week in Rust is edited by: [nellshamrell](https://github.com/nellshamrell), [llogiq](https://github.com/llogiq), [cdmistman](https://github.com/cdmistman), [ericseppanen](https://github.com/ericseppanen), [extrawurst](https://github.com/extrawurst), [andrewpollack](https://github.com/andrewpollack), [U007D](https://github.com/U007D), [kolharsam](https://github.com/kolharsam), [joelmarcey](https://github.com/joelmarcey), [mariannegoldin](https://github.com/mariannegoldin).*
+
+*Email list hosting is sponsored by [The Rust Foundation](https://foundation.rust-lang.org/)*
+
+<small>[Discuss on r/rust](https://www.reddit.com/r/rust/comments/k5nsab/this_week_in_rust_367/)</small>