samplee output

Author: tshepang

src/walkthrough.md

@@ -1,19 +1,19 @@
 # Walkthrough: a typical contribution
 
 There are _a lot_ of ways to contribute to the Rust compiler, including fixing
-bugs, improving performance, helping design features, providing feedback on
-existing features, etc. This chapter does not claim to scratch the surface.
-Instead, it walks through the design and implementation of a new feature. Not
-all of the steps and processes described here are needed for every
+bugs, improving performance, helping design features, providing feedback on existing features, etc.
+This chapter does not claim to scratch the surface.
+Instead, it walks through the design and implementation of a new feature.
+Not all of the steps and processes described here are needed for every
 contribution, and I will try to point those out as they arise.
 
 In general, if you are interested in making a contribution and aren't sure
 where to start, please feel free to ask!
 
 ## Overview
 
-The feature I will discuss in this chapter is the `?` Kleene operator for
-macros. Basically, we want to be able to write something like this:
+The feature I will discuss in this chapter is the `?` Kleene operator for macros.
+Basically, we want to be able to write something like this:
 
 ```rust,ignore
 macro_rules! foo {
@@ -36,25 +36,30 @@ fn main() {
 So basically, the `$(pat)?` matcher in the macro means "this pattern can occur
 0 or 1 times", similar to other regex syntaxes.
 
-There were a number of steps to go from an idea to stable Rust feature. Here is
-a quick list.  We will go through each of these in order below. As I mentioned
-before, not all of these are needed for every type of contribution.
+There were a number of steps to go from an idea to stable Rust feature.
+Here is a quick list.
+We will go through each of these in order below.
+As I mentioned before, not all of these are needed for every type of contribution.
 
 - **Idea discussion/Pre-RFC**  A Pre-RFC is an early draft or design discussion
-  of a feature. This stage is intended to flesh out the design space a bit and
-  get a grasp on the different merits and problems with an idea. It's a great
-  way to get early feedback on your idea before presenting it to the wider
-  audience. You can find the original discussion [here][prerfc].
+  of a feature.
+  This stage is intended to flesh out the design space a bit and
+  get a grasp on the different merits and problems with an idea.
+  It's a great   way to get early feedback on your idea before presenting it to the wider
+  audience.
+  You can find the original discussion [here][prerfc].
 - **RFC**  This is when you formally present your idea to the community for
-  consideration. You can find the RFC [here][rfc].
+  consideration.
+  You can find the RFC [here][rfc].
 - **Implementation** Implement your idea unstably in the compiler. You can
   find the original implementation [here][impl1].
 - **Possibly iterate/refine** As the community gets experience with your
   feature on the nightly compiler and in `std`, there may be additional
-  feedback about design choice that might be adjusted. This particular feature
-  went [through][impl2] a [number][impl3] of [iterations][impl4].
+  feedback about design choice that might be adjusted.
+  This particular feature   went [through][impl2] a [number][impl3] of [iterations][impl4].
 - **Stabilization** When your feature has baked enough, a Rust team member may
-  [propose to stabilize it][merge]. If there is consensus, this is done.
+  [propose to stabilize it][merge].
+  If there is consensus, this is done.
 - **Relax** Your feature is now a stable Rust feature!
 
 [prerfc]: https://internals.rust-lang.org/t/pre-rfc-at-most-one-repetition-macro-patterns/6557
@@ -75,58 +80,62 @@ before, not all of these are needed for every type of contribution.
 
 [rfcwhen]: https://github.com/rust-lang/rfcs#when-you-need-to-follow-this-process
 
-An RFC is a document that describes the feature or change you are proposing in
-detail. Anyone can write an RFC; the process is the same for everyone,
+An RFC is a document that describes the feature or change you are proposing in detail.
+Anyone can write an RFC; the process is the same for everyone,
 including Rust team members.
 
-To open an RFC, open a PR on the
-[rust-lang/rfcs](https://github.com/rust-lang/rfcs) repo on GitHub. You can
-find detailed instructions in the
+To open an RFC, open a PR on the [rust-lang/rfcs](https://github.com/rust-lang/rfcs) repo on GitHub.
+You can find detailed instructions in the
 [README](https://github.com/rust-lang/rfcs#what-the-process-is).
 
 Before opening an RFC, you should do the research to "flesh out" your idea.
-Hastily-proposed RFCs tend not to be accepted. You should generally have a good
-description of the motivation, impact, disadvantages, and potential
+Hastily-proposed RFCs tend not to be accepted.
+You should generally have a good description of the motivation, impact, disadvantages, and potential
 interactions with other features.
 
-If that sounds like a lot of work, it's because it is. But no fear! Even if
+If that sounds like a lot of work, it's because it is.
+But no fear! Even if
 you're not a compiler hacker, you can get great feedback by doing a _pre-RFC_.
-This is an _informal_ discussion of the idea. The best place to do this is
-internals.rust-lang.org. Your post doesn't have to follow any particular
-structure.  It doesn't even need to be a cohesive idea. Generally, you will get
-tons of feedback that you can integrate back to produce a good RFC.
+This is an _informal_ discussion of the idea.
+The best place to do this is internals.rust-lang.org.
+Your post doesn't have to follow any particular structure.
+It doesn't even need to be a cohesive idea.
+Generally, you will get tons of feedback that you can integrate back to produce a good RFC.
 
-(Another pro-tip: try searching the RFCs repo and internals for prior related
-ideas. A lot of times an idea has already been considered and was either
-rejected or postponed to be tried again later. This can save you and everybody
-else some time)
+(Another pro-tip: try searching the RFCs repo and internals for prior related ideas.
+A lot of times an idea has already been considered and was either
+rejected or postponed to be tried again later.
+This can save you and everybody else some time)
 
 In the case of our example, a participant in the pre-RFC thread pointed out a
-syntax ambiguity and a potential resolution. Also, the overall feedback seemed
-positive. In this case, the discussion converged pretty quickly, but for some
+syntax ambiguity and a potential resolution.
+Also, the overall feedback seemed positive.
+In this case, the discussion converged pretty quickly, but for some
 ideas, a lot more discussion can happen (e.g. see [this RFC][nonascii] which
-received a whopping 684 comments!). If that happens, don't be discouraged; it
-means the community is interested in your idea, but it perhaps needs some
-adjustments.
+received a whopping 684 comments!).
+If that happens, don't be discouraged; it
+means the community is interested in your idea, but it perhaps needs some adjustments.
 
 [nonascii]: https://github.com/rust-lang/rfcs/pull/2457
 
-The RFC for our `?` macro feature did receive some discussion on the RFC thread
-too.  As with most RFCs, there were a few questions that we couldn't answer by
-discussion: we needed experience using the feature to decide. Such questions
-are listed in the "Unresolved Questions" section of the RFC. Also, over the
-course of the RFC discussion, you will probably want to update the RFC document
+The RFC for our `?` macro feature did receive some discussion on the RFC thread too.
+As with most RFCs, there were a few questions that we couldn't answer by
+discussion: we needed experience using the feature to decide.
+Such questions are listed in the "Unresolved Questions" section of the RFC.
+Also, over the course of the RFC discussion, you will probably want to update the RFC document
 itself to reflect the course of the discussion (e.g. new alternatives or prior
 work may be added or you may decide to change parts of the proposal itself).
 
 In the end, when the discussion seems to reach a consensus and die down a bit,
 a Rust team member may propose to move to "final comment period" (FCP) with one
-of three possible dispositions. This means that they want the other members of
-the appropriate teams to review and comment on the RFC. More discussion may
-ensue, which may result in more changes or unresolved questions being added. At
-some point, when everyone is satisfied, the RFC enters the FCP, which is the
-last chance for people to bring up objections. When the FCP is over, the
-disposition is adopted. Here are the three possible dispositions:
+of three possible dispositions.
+This means that they want the other members of
+the appropriate teams to review and comment on the RFC.
+More discussion may ensue, which may result in more changes or unresolved questions being added.
+At some point, when everyone is satisfied, the RFC enters the FCP, which is the
+last chance for people to bring up objections.
+When the FCP is over, the disposition is adopted.
+Here are the three possible dispositions:
 
 - _Merge_: accept the feature. Here is the proposal to merge for our [`?` macro
   feature][rfcmerge].
@@ -136,14 +145,14 @@ disposition is adopted. Here are the three possible dispositions:
   will go a different direction.
 - _Postpone_: there is interest in going this direction but not at the moment.
   This happens most often because the appropriate Rust team doesn't have the
-  bandwidth to shepherd the feature through the process to stabilization. Often
-  this is the case when the feature doesn't fit into the team's roadmap.
+  bandwidth to shepherd the feature through the process to stabilization.
+  Often   this is the case when the feature doesn't fit into the team's roadmap.
   Postponed ideas may be revisited later.
 
 [rfcmerge]: https://github.com/rust-lang/rfcs/pull/2298#issuecomment-360582667
 
-When an RFC is merged, the PR is merged into the RFCs repo. A new _tracking
-issue_ is created in the [rust-lang/rust] repo to track progress on the feature
+When an RFC is merged, the PR is merged into the RFCs repo.
+A new _tracking issue_ is created in the [rust-lang/rust] repo to track progress on the feature
 and discuss unresolved questions, implementation progress and blockers, etc.
 Here is the tracking issue on for our [`?` macro feature][tracking].
 
@@ -158,66 +167,71 @@ To make a change to the compiler, open a PR against the [rust-lang/rust] repo.
 [rust-lang/rust]: https://github.com/rust-lang/rust
 
 Depending on the feature/change/bug fix/improvement, implementation may be
-relatively-straightforward or it may be a major undertaking. You can always ask
-for help or mentorship from more experienced compiler devs.  Also, you don't
-have to be the one to implement your feature; but keep in mind that if you
-don't, it might be a while before someone else does.
+relatively-straightforward or it may be a major undertaking.
+You can always ask for help or mentorship from more experienced compiler devs.
+Also, you don't have to be the one to implement your feature;
+but keep in mind that if you don't, it might be a while before someone else does.
 
 For the `?` macro feature, I needed to go understand the relevant parts of
-macro expansion in the compiler. Personally, I find that [improving the
+macro expansion in the compiler.
+Personally, I find that [improving the
 comments][comments] in the code is a helpful way of making sure I understand
 it, but you don't have to do that if you don't want to.
 
 [comments]: https://github.com/rust-lang/rust/pull/47732
 
-I then [implemented][impl1] the original feature, as described in the RFC. When
-a new feature is implemented, it goes behind a _feature gate_, which means that
-you have to use `#![feature(my_feature_name)]` to use the feature. The feature
-gate is removed when the feature is stabilized.
+I then [implemented][impl1] the original feature, as described in the RFC.
+When a new feature is implemented, it goes behind a _feature gate_, which means that
+you have to use `#![feature(my_feature_name)]` to use the feature.
+The feature gate is removed when the feature is stabilized.
 
 **Most bug fixes and improvements** don't require a feature gate. You can just
 make your changes/improvements.
 
-When you open a PR on the [rust-lang/rust], a bot will assign your PR to a
-reviewer. If there is a particular Rust team member you are working with, you can
+When you open a PR on the [rust-lang/rust], a bot will assign your PR to a reviewer.
+If there is a particular Rust team member you are working with, you can
 request that reviewer by leaving a comment on the thread with `r?
 @reviewer-github-id` (e.g. `r? @eddyb`). If you don't know who to request,
 don't request anyone; the bot will assign someone automatically based on which files you changed.
 
 The reviewer may request changes before they approve your PR, they may mark the PR with label 
 "S-waiting-on-author" after leaving comments, this means that the PR is blocked on you to make 
-some requested changes. When you finished iterating on the changes, you can mark the PR as 
+some requested changes.
+When you finished iterating on the changes, you can mark the PR as
 `S-waiting-on-review` again by leaving a comment with `@rustbot ready`, this will remove the 
 `S-waiting-on-author` label and add the `S-waiting-on-review` label.
 
-Feel free to ask questions or discuss things you don't understand or disagree with. However,
-recognize that the PR won't be merged unless someone on the Rust team approves
-it. If a reviewer leave a comment like `r=me after fixing ...`, that means they approve the PR and 
+Feel free to ask questions or discuss things you don't understand or disagree with.
+However, recognize that the PR won't be merged unless someone on the Rust team approves
+it.
+If a reviewer leave a comment like `r=me after fixing ...`, that means they approve the PR and
 you can merge it with comment with `@bors r=reviewer-github-id`(e.g. `@bors r=eddyb`) to merge it 
-after fixing trivial issues. Note that `r=someone` requires permission and bors could say 
-something like "🔑 Insufficient privileges..." when commenting `r=someone`. In that case, 
-you have to ask the reviewer to revisit your PR.
-
-When your reviewer approves the PR, it will go into a queue for yet another bot
-called `@bors`. `@bors` manages the CI build/merge queue. When your PR reaches
-the head of the `@bors` queue, `@bors` will test out the merge by running all
-tests against your PR on GitHub Actions. This takes a lot of time to
-finish. If all tests pass, the PR is merged and becomes part of the next
-nightly compiler!
+after fixing trivial issues.
+Note that `r=someone` requires permission and bors could say
+something like "🔑 Insufficient privileges..." when commenting `r=someone`.
+In that case, you have to ask the reviewer to revisit your PR.
+
+When your reviewer approves the PR, it will go into a queue for yet another bot called `@bors`.
+`@bors` manages the CI build/merge queue.
+When your PR reaches the head of the `@bors` queue, `@bors` will test out the merge by running all
+tests against your PR on GitHub Actions.
+This takes a lot of time to finish.
+If all tests pass, the PR is merged and becomes part of the next nightly compiler!
 
 There are a couple of things that may happen for some PRs during the review process
 
 - If the change is substantial enough, the reviewer may request an FCP on
-  the PR. This gives all members of the appropriate team a chance to review the
-  changes.
+  the PR.
+  This gives all members of the appropriate team a chance to review the   changes.
 - If the change may cause breakage, the reviewer may request a [crater] run.
   This compiles the compiler with your changes and then attempts to compile all
-  crates on crates.io with your modified compiler. This is a great smoke test
+  crates on crates.io with your modified compiler.
+  This is a great smoke test
   to check if you introduced a change to compiler behavior that affects a large
   portion of the ecosystem.
 - If the diff of your PR is large or the reviewer is busy, your PR may have
-  some merge conflicts with other PRs that happen to get merged first. You
-  should fix these merge conflicts using the normal git procedures.
+  some merge conflicts with other PRs that happen to get merged first.
+  You   should fix these merge conflicts using the normal git procedures.
 
 [crater]: ./tests/crater.html
 
@@ -227,24 +241,22 @@ fixing a bug), then that's it! Thanks for your contribution :)
 ## Refining your implementation
 
 As people get experience with your new feature on nightly, slight changes may
-be proposed and unresolved questions may become resolved. Updates/changes go
-through the same process for implementing any other changes, as described
+be proposed and unresolved questions may become resolved.
+Updates/changes go through the same process for implementing any other changes, as described
 above (i.e. submit a PR, go through review, wait for `@bors`, etc).
 
-Some changes may be major enough to require an FCP and some review by Rust team
-members.
+Some changes may be major enough to require an FCP and some review by Rust team members.
 
 For the `?` macro feature, we went through a few different iterations after the
 original implementation: [1][impl2], [2][impl3], [3][impl4].
 
 Along the way, we decided that `?` should not take a separator, which was
-previously an unresolved question listed in the RFC. We also changed the
-disambiguation strategy: we decided to remove the ability to use `?` as a
+previously an unresolved question listed in the RFC.
+We also changed the disambiguation strategy: we decided to remove the ability to use `?` as a
 separator token for other repetition operators (e.g. `+` or `*`). However,
 since this was a breaking change, we decided to do it over an edition boundary.
 Thus, the new feature can be enabled only in edition 2018. These deviations
-from the original RFC required [another
-FCP](https://github.com/rust-lang/rust/issues/51934).
+from the original RFC required [another FCP](https://github.com/rust-lang/rust/issues/51934).
 
 ## Stabilization
 
@@ -264,8 +276,8 @@ The stabilization report for our feature is [here][stabrep].
 [stabrep]: https://github.com/rust-lang/rust/issues/48075#issuecomment-433243048
 
 After this, [a PR is made][stab] to remove the feature gate, enabling the feature by
-default (on the 2018 edition). A note is added to the [Release notes][relnotes]
-about the feature.
+default (on the 2018 edition).
+A note is added to the [Release notes][relnotes] about the feature.
 
 [stab]: https://github.com/rust-lang/rust/pull/56245