2 [contributing-to-rust]: #contributing-to-rust
4 Thank you for your interest in contributing to Rust! There are many ways to
5 contribute, and we appreciate all of them. This document is a bit long, so here's
6 links to the major sections:
8 * [Feature Requests](#feature-requests)
9 * [Bug Reports](#bug-reports)
10 * [The Build System](#the-build-system)
11 * [Pull Requests](#pull-requests)
12 * [Writing Documentation](#writing-documentation)
13 * [Issue Triage](#issue-triage)
14 * [Out-of-tree Contributions](#out-of-tree-contributions)
15 * [Helpful Links and Information](#helpful-links-and-information)
17 If you have questions, please make a post on [internals.rust-lang.org][internals] or
18 hop on [#rust-internals][pound-rust-internals].
20 As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
22 [pound-rust-internals]: https://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-internals
23 [internals]: https://internals.rust-lang.org
24 [coc]: https://www.rust-lang.org/conduct.html
27 [feature-requests]: #feature-requests
29 To request a change to the way the Rust language works, please head over
30 to the [RFCs repository](https://github.com/rust-lang/rfcs) and view the
31 [README](https://github.com/rust-lang/rfcs/blob/master/README.md)
35 [bug-reports]: #bug-reports
37 While bugs are unfortunate, they're a reality in software. We can't fix what we
38 don't know about, so please report liberally. If you're not sure if something
39 is a bug or not, feel free to file a bug anyway.
41 **If you believe reporting your bug publicly represents a security risk to Rust users,
42 please follow our [instructions for reporting security vulnerabilities](https://www.rust-lang.org/security.html)**.
44 If you have the chance, before reporting a bug, please [search existing
45 issues](https://github.com/rust-lang/rust/search?q=&type=Issues&utf8=%E2%9C%93),
46 as it's possible that someone else has already reported your error. This doesn't
47 always work, and sometimes it's hard to know what to search for, so consider this
48 extra credit. We won't mind if you accidentally file a duplicate report.
50 Opening an issue is as easy as following [this
51 link](https://github.com/rust-lang/rust/issues/new) and filling out the fields.
52 Here's a template that you can use to file a bug, though it's not necessary to
55 <short summary of the bug>
59 <code sample that causes the bug>
61 I expected to see this happen: <explanation>
63 Instead, this happened: <explanation>
67 `rustc --version --verbose`:
71 All three components are important: what you did, what you expected, what
72 happened instead. Please include the output of `rustc --version --verbose`,
73 which includes important information about what platform you're on, what
74 version of Rust you're using, etc.
76 Sometimes, a backtrace is helpful, and so including that is nice. To get
77 a backtrace, set the `RUST_BACKTRACE` environment variable to a value
78 other than `0`. The easiest way
79 to do this is to invoke `rustc` like this:
82 $ RUST_BACKTRACE=1 rustc ...
86 [the-build-system]: #the-build-system
88 Rust's build system allows you to bootstrap the compiler, run tests &
89 benchmarks, generate documentation, install a fresh build of Rust, and more.
90 It's your best friend when working on Rust, allowing you to compile & test
91 your contributions before submission.
93 The build system lives in [the `src/bootstrap` directory][bootstrap] in the
94 project root. Our build system is itself written in Rust and is based on Cargo
95 to actually build all the compiler's crates. If you have questions on the build
96 system internals, try asking in [`#rust-internals`][pound-rust-internals].
98 [bootstrap]: https://github.com/rust-lang/rust/tree/master/src/bootstrap/
101 [configuration]: #configuration
103 Before you can start building the compiler you need to configure the build for
104 your system. In most cases, that will just mean using the defaults provided
107 To change configuration, you must copy the file `config.toml.example`
108 to `config.toml` in the directory from which you will be running the build, and
109 change the settings provided.
111 There are large number of options provided in this config file that will alter the
112 configuration used in the build process. Some options to note:
115 - `assertions = true` = This enables LLVM assertions, which makes LLVM misuse cause an assertion failure instead of weird misbehavior. This also slows down the compiler's runtime by ~20%.
116 - `ccache = true` - Use ccache when building llvm
119 - `compiler-docs = true` - Build compiler documentation
122 - `debuginfo = true` - Build a compiler with debuginfo. Makes building rustc slower, but then you can use a debugger to debug `rustc`.
123 - `debuginfo-lines = true` - An alternative to `debuginfo = true` that doesn't let you use a debugger, but doesn't make building rustc slower and still gives you line numbers in backtraces.
124 - `debuginfo-tools = true` - Build the extended tools with debuginfo.
125 - `debug-assertions = true` - Makes the log output of `debug!` work.
126 - `optimize = false` - Disable optimizations to speed up compilation of stage1 rust, but makes the stage1 compiler x100 slower.
128 For more options, the `config.toml` file contains commented out defaults, with
129 descriptions of what each option will do.
131 Note: Previously the `./configure` script was used to configure this
132 project. It can still be used, but it's recommended to use a `config.toml`
133 file. If you still have a `config.mk` file in your directory - from
134 `./configure` - you may need to delete it for `config.toml` to work.
137 [building]: #building
140 - [build dependencies](README.md#building-from-source)
141 - `gdb` 6.2.0 minimum, 7.1 or later recommended for test builds
143 The build system uses the `x.py` script to control the build process. This script
144 is used to build, test, and document various parts of the compiler. You can
151 On some systems you can also use the shorter version:
157 To learn more about the driver and top-level targets, you can execute:
163 The general format for the driver script is:
166 python x.py <command> [<directory>]
169 Some example commands are `build`, `test`, and `doc`. These will build, test,
170 and document the specified directory. The second argument, `<directory>`, is
171 optional and defaults to working over the entire compiler. If specified,
172 however, only that specific directory will be built. For example:
175 # build the entire compiler
178 # build all documentation
181 # run all test suites
184 # build only the standard library
185 python x.py build src/libstd
187 # test only one particular test suite
188 python x.py test src/test/rustdoc
190 # build only the stage0 libcore library
191 python x.py build src/libcore --stage 0
194 You can explore the build system through the various `--help` pages for each
195 subcommand. For example to learn more about a command you can run:
198 python x.py build --help
201 To learn about all possible rules you can execute, run:
204 python x.py build --help --verbose
207 Note: Previously `./configure` and `make` were used to build this project.
208 They are still available, but `x.py` is the recommended build system.
211 [useful-commands]: #useful-commands
213 Some common invocations of `x.py` are:
215 - `x.py build --help` - show the help message and explain the subcommand
216 - `x.py build src/libtest --stage 1` - build up to (and including) the first
217 stage. For most cases we don't need to build the stage2 compiler, so we can
218 save time by not building it. The stage1 compiler is a fully functioning
219 compiler and (probably) will be enough to determine if your change works as
221 - `x.py build src/rustc --stage 1` - This will build just rustc, without libstd.
222 This is the fastest way to recompile after you changed only rustc source code.
223 Note however that the resulting rustc binary won't have a stdlib to link
224 against by default. You can build libstd once with `x.py build src/libstd`,
225 but it is only guaranteed to work if recompiled, so if there are any issues
227 - `x.py test` - build the full compiler & run all tests (takes a while). This
228 is what gets run by the continuous integration system against your pull
229 request. You should run this before submitting to make sure your tests pass
230 & everything builds in the correct manner.
231 - `x.py test src/libstd --stage 1` - test the standard library without
233 - `x.py test src/test/run-pass --test-args TESTNAME` - Run a matching set of
235 - `TESTNAME` should be a substring of the tests to match against e.g. it could
236 be the fully qualified test name, or just a part of it.
237 `TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`
238 or `TESTNAME=test_capacity_not_less_than_len`.
239 - `x.py test src/test/run-pass --stage 1 --test-args <substring-of-test-name>` -
240 Run a single rpass test with the stage1 compiler (this will be quicker than
241 running the command above as we only build the stage1 compiler, not the entire
242 thing). You can also leave off the directory argument to run all stage1 test
244 - `x.py test src/libcore --stage 1` - Run stage1 tests in `libcore`.
245 - `x.py test src/tools/tidy` - Check that the source code is in compliance with
246 Rust's style guidelines. There is no official document describing Rust's full
247 guidelines as of yet, but basic rules like 4 spaces for indentation and no
248 more than 99 characters in a single line should be kept in mind when writing
251 ### Using your local build
252 [using-local-build]: #using-local-build
254 If you use Rustup to manage your rust install, it has a feature called ["custom
255 toolchains"][toolchain-link] that you can use to access your newly-built compiler
256 without having to install it to your system or user PATH. If you've run `python
257 x.py build`, then you can add your custom rustc to a new toolchain like this:
259 [toolchain-link]: https://github.com/rust-lang-nursery/rustup.rs#working-with-custom-toolchains-and-local-builds
262 rustup toolchain link <name> build/<host-triple>/stage2
265 Where `<host-triple>` is the build triple for the host (the triple of your
266 computer, by default), and `<name>` is the name for your custom toolchain. (If you
267 added `--stage 1` to your build command, the compiler will be in the `stage1`
268 folder instead.) You'll only need to do this once - it will automatically point
269 to the latest build you've done.
271 Once this is set up, you can use your custom toolchain just like any other. For
272 example, if you've named your toolchain `local`, running `cargo +local build` will
273 compile a project with your custom rustc, setting `rustup override set local` will
274 override the toolchain for your current directory, and `cargo +local doc` will use
275 your custom rustc and rustdoc to generate docs. (If you do this with a `--stage 1`
276 build, you'll need to build rustdoc specially, since it's not normally built in
277 stage 1. `python x.py build --stage 1 src/libstd src/tools/rustdoc` will build
278 rustdoc and libstd, which will allow rustdoc to be run with that toolchain.)
280 ### Out-of-tree builds
281 [out-of-tree-builds]: #out-of-tree-builds
283 Rust's `x.py` script fully supports out-of-tree builds - it looks for
284 the Rust source code from the directory `x.py` was found in, but it
285 reads the `config.toml` configuration file from the directory it's
286 run in, and places all build artifacts within a subdirectory named `build`.
288 This means that if you want to do an out-of-tree build, you can just do it:
291 $ cp ~/my-config.toml config.toml # Or fill in config.toml otherwise
292 $ path/to/rust/x.py build
294 $ # This will use the Rust source code in `path/to/rust`, but build
295 $ # artifacts will now be in ./build
298 It's absolutely fine to have multiple build directories with different
299 `config.toml` configurations using the same code.
302 [pull-requests]: #pull-requests
304 Pull requests are the primary mechanism we use to change Rust. GitHub itself
305 has some [great documentation][about-pull-requests] on using the Pull Request feature.
306 We use the "fork and pull" model [described here][development-models], where
307 contributors push changes to their personal fork and create pull requests to
308 bring those changes into the source repository.
310 [about-pull-requests]: https://help.github.com/articles/about-pull-requests/
311 [development-models]: https://help.github.com/articles/about-collaborative-development-models/
313 Please make pull requests against the `master` branch.
315 Compiling all of `./x.py test` can take a while. When testing your pull request,
316 consider using one of the more specialized `./x.py` targets to cut down on the
317 amount of time you have to wait. You need to have built the compiler at least
318 once before running these will work, but that’s only one full build rather than
321 $ python x.py test --stage 1
323 is one such example, which builds just `rustc`, and then runs the tests. If
324 you’re adding something to the standard library, try
326 $ python x.py test src/libstd --stage 1
328 Please make sure your pull request is in compliance with Rust's style
329 guidelines by running
331 $ python x.py test src/tools/tidy
333 Make this check before every pull request (and every new commit in a pull
334 request) ; you can add [git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)
335 before every push to make sure you never forget to make this check.
337 All pull requests are reviewed by another person. We have a bot,
338 @rust-highfive, that will automatically assign a random person to review your
341 If you want to request that a specific person reviews your pull request,
342 you can add an `r?` to the message. For example, Steve usually reviews
343 documentation changes. So if you were to make a documentation change, add
347 to the end of the message, and @rust-highfive will assign @steveklabnik instead
348 of a random person. This is entirely optional.
350 After someone has reviewed your pull request, they will leave an annotation
351 on the pull request with an `r+`. It will look something like this:
355 This tells @bors, our lovable integration bot, that your pull request has
356 been approved. The PR then enters the [merge queue][merge-queue], where @bors
357 will run all the tests on every platform we support. If it all works out,
358 @bors will merge your code into `master` and close the pull request.
360 [merge-queue]: https://buildbot2.rust-lang.org/homu/queue/rust
362 Speaking of tests, Rust has a comprehensive test suite. More information about
364 [here](https://github.com/rust-lang/rust/blob/master/src/test/COMPILER_TESTS.md).
366 ### External Dependencies
367 [external-dependencies]: #external-dependencies
369 Currently building Rust will also build the following external projects:
371 * [clippy](https://github.com/rust-lang-nursery/rust-clippy)
372 * [miri](https://github.com/solson/miri)
373 * [rustfmt](https://github.com/rust-lang-nursery/rustfmt)
374 * [rls](https://github.com/rust-lang-nursery/rls/)
376 We allow breakage of these tools in the nightly channel. Maintainers of these
377 projects will be notified of the breakages and should fix them as soon as
380 After the external is fixed, one could add the changes with
383 git add path/to/submodule
386 outside the submodule.
388 In order to prepare your tool-fixing PR, you can run the build locally by doing
389 `./x.py build src/tools/TOOL`. If you will be editing the sources
390 there, you may wish to set `submodules = false` in the `config.toml`
391 to prevent `x.py` from resetting to the original branch.
393 Breakage is not allowed in the beta and stable channels, and must be addressed
394 before the PR is merged.
396 #### Breaking Tools Built With The Compiler
397 [breaking-tools-built-with-the-compiler]: #breaking-tools-built-with-the-compiler
399 Rust's build system builds a number of tools that make use of the
400 internals of the compiler. This includes clippy,
401 [RLS](https://github.com/rust-lang-nursery/rls) and
402 [rustfmt](https://github.com/rust-lang-nursery/rustfmt). If these tools
403 break because of your changes, you may run into a sort of "chicken and egg"
404 problem. These tools rely on the latest compiler to be built so you can't update
405 them to reflect your changes to the compiler until those changes are merged into
406 the compiler. At the same time, you can't get your changes merged into the compiler
407 because the rust-lang/rust build won't pass until those tools build and pass their
410 That means that, in the default state, you can't update the compiler without first
411 fixing rustfmt, rls and the other tools that the compiler builds.
413 Luckily, a feature was [added to Rust's build](https://github.com/rust-lang/rust/issues/45861)
414 to make all of this easy to handle. The idea is that we allow these tools to be "broken",
415 so that the rust-lang/rust build passes without trying to build them, then land the change
416 in the compiler, wait for a nightly, and go update the tools that you broke. Once you're done
417 and the tools are working again, you go back in the compiler and update the tools
418 so they can be distributed again.
420 This should avoid a bunch of synchronization dances and is also much easier on contributors as
421 there's no need to block on rls/rustfmt/other tools changes going upstream.
423 Here are those same steps in detail:
425 1. (optional) First, if it doesn't exist already, create a `config.toml` by copying
426 `config.toml.example` in the root directory of the Rust repository.
427 Set `submodules = false` in the `[build]` section. This will prevent `x.py`
428 from resetting to the original branch after you make your changes. If you
429 need to [update any submodules to their latest versions][updating-submodules],
430 see the section of this file about that for more information.
431 2. (optional) Run `./x.py test src/tools/rustfmt` (substituting the submodule
432 that broke for `rustfmt`). Fix any errors in the submodule (and possibly others).
433 3. (optional) Make commits for your changes and send them to upstream repositories as a PR.
434 4. (optional) Maintainers of these submodules will **not** merge the PR. The PR can't be
435 merged because CI will be broken. You'll want to write a message on the PR referencing
436 your change, and how the PR should be merged once your change makes it into a nightly.
437 5. Wait for your PR to merge.
438 6. Wait for a nightly
439 7. (optional) Help land your PR on the upstream repository now that your changes are in nightly.
440 8. (optional) Send a PR to rust-lang/rust updating the submodule.
442 #### Updating submodules
443 [updating-submodules]: #updating-submodules
445 These instructions are specific to updating `rustfmt`, however they may apply
446 to the other submodules as well. Please help by improving these instructions
447 if you find any discrepancies or special cases that need to be addressed.
449 To update the `rustfmt` submodule, start by running the appropriate
450 [`git submodule` command](https://git-scm.com/book/en/v2/Git-Tools-Submodules).
451 For example, to update to the latest commit on the remote master branch,
454 git submodule update --remote src/tools/rustfmt
456 If you run `./x.py build` now, and you are lucky, it may just work. If you see
457 an error message about patches that did not resolve to any crates, you will need
458 to complete a few more steps which are outlined with their rationale below.
460 *(This error may change in the future to include more information.)*
462 error: failed to resolve patches for `https://github.com/rust-lang-nursery/rustfmt`
465 patch for `rustfmt-nightly` in `https://github.com/rust-lang-nursery/rustfmt` did not resolve to any crates
466 failed to run: ~/rust/build/x86_64-unknown-linux-gnu/stage0/bin/cargo build --manifest-path ~/rust/src/bootstrap/Cargo.toml
469 If you haven't used the `[patch]`
470 section of `Cargo.toml` before, there is [some relevant documentation about it
471 in the cargo docs](http://doc.crates.io/manifest.html#the-patch-section). In
472 addition to that, you should read the
473 [Overriding dependencies](http://doc.crates.io/specifying-dependencies.html#overriding-dependencies)
474 section of the documentation as well.
476 Specifically, the following [section in Overriding dependencies](http://doc.crates.io/specifying-dependencies.html#testing-a-bugfix) reveals what the problem is:
478 > Next up we need to ensure that our lock file is updated to use this new version of uuid so our project uses the locally checked out copy instead of one from crates.io. The way [patch] works is that it'll load the dependency at ../path/to/uuid and then whenever crates.io is queried for versions of uuid it'll also return the local version.
480 > This means that the version number of the local checkout is significant and will affect whether the patch is used. Our manifest declared uuid = "1.0" which means we'll only resolve to >= 1.0.0, < 2.0.0, and Cargo's greedy resolution algorithm also means that we'll resolve to the maximum version within that range. Typically this doesn't matter as the version of the git repository will already be greater or match the maximum version published on crates.io, but it's important to keep this in mind!
482 This says that when we updated the submodule, the version number in our
483 `src/tools/rustfmt/Cargo.toml` changed. The new version is different from
484 the version in `Cargo.lock`, so the build can no longer continue.
486 To resolve this, we need to update `Cargo.lock`. Luckily, cargo provides a
487 command to do this easily.
489 First, go into the `src/` directory since that is where `Cargo.toml` is in
490 the rust repository. Then run, `cargo update -p rustfmt-nightly` to solve
495 $ cargo update -p rustfmt-nightly
498 This should change the version listed in `src/Cargo.lock` to the new version you updated
499 the submodule to. Running `./x.py build` should work now.
501 ## Writing Documentation
502 [writing-documentation]: #writing-documentation
504 Documentation improvements are very welcome. The source of `doc.rust-lang.org`
505 is located in `src/doc` in the tree, and standard API documentation is generated
506 from the source code itself.
508 Documentation pull requests function in the same way as other pull requests,
509 though you may see a slightly different form of `r+`:
511 @bors: r+ 38fe8d2 rollup
513 That additional `rollup` tells @bors that this change is eligible for a 'rollup'.
514 To save @bors some work, and to get small changes through more quickly, when
515 @bors attempts to merge a commit that's rollup-eligible, it will also merge
516 the other rollup-eligible patches too, and they'll get tested and merged at
519 To find documentation-related issues, sort by the [T-doc label][tdoc].
521 [tdoc]: https://github.com/rust-lang/rust/issues?q=is%3Aopen%20is%3Aissue%20label%3AT-doc
523 You can find documentation style guidelines in [RFC 1574][rfc1574].
525 [rfc1574]: https://github.com/rust-lang/rfcs/blob/master/text/1574-more-api-documentation-conventions.md#appendix-a-full-conventions-text
527 In many cases, you don't need a full `./x.py doc`. You can use `rustdoc` directly
528 to check small fixes. For example, `rustdoc src/doc/reference.md` will render
529 reference to `doc/reference.html`. The CSS might be messed up, but you can
530 verify that the HTML is right.
533 [issue-triage]: #issue-triage
535 Sometimes, an issue will stay open, even though the bug has been fixed. And
536 sometimes, the original bug may go stale because something has changed in the
539 It can be helpful to go through older bug reports and make sure that they are
540 still valid. Load up an older issue, double check that it's still true, and
541 leave a comment letting us know if it is or is not. The [least recently
542 updated sort][lru] is good for finding issues like this.
544 Contributors with sufficient permissions on the Rust repo can help by adding
545 labels to triage issues:
547 * Yellow, **A**-prefixed labels state which **area** of the project an issue
550 * Magenta, **B**-prefixed labels identify bugs which are **blockers**.
552 * Dark blue, **beta-** labels track changes which need to be backported into
555 * Light purple, **C**-prefixed labels represent the **category** of an issue.
557 * Green, **E**-prefixed labels explain the level of **experience** necessary
560 * The dark blue **final-comment-period** label marks bugs that are using the
561 RFC signoff functionality of [rfcbot][rfcbot] and are currenty in the final
564 * Red, **I**-prefixed labels indicate the **importance** of the issue. The
565 [I-nominated][inom] label indicates that an issue has been nominated for
566 prioritizing at the next triage meeting.
568 * The purple **metabug** label marks lists of bugs collected by other
571 * Purple gray, **O**-prefixed labels are the **operating system** or platform
572 that this issue is specific to.
574 * Orange, **P**-prefixed labels indicate a bug's **priority**. These labels
575 are only assigned during triage meetings, and replace the [I-nominated][inom]
578 * The gray **proposed-final-comment-period** label marks bugs that are using
579 the RFC signoff functionality of [rfcbot][rfcbot] and are currently awaiting
580 signoff of all team members in order to enter the final comment period.
582 * Pink, **regression**-prefixed labels track regressions from stable to the
585 * The light orange **relnotes** label marks issues that should be documented in
586 the release notes of the next release.
588 * Gray, **S**-prefixed labels are used for tracking the **status** of pull
591 * Blue, **T**-prefixed bugs denote which **team** the issue belongs to.
593 If you're looking for somewhere to start, check out the [E-easy][eeasy] tag.
595 [inom]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AI-nominated
596 [eeasy]: https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy
597 [lru]: https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-asc
598 [rfcbot]: https://github.com/anp/rfcbot-rs/
600 ## Out-of-tree Contributions
601 [out-of-tree-contributions]: #out-of-tree-contributions
603 There are a number of other ways to contribute to Rust that don't deal with
606 Answer questions in [#rust][pound-rust], or on [users.rust-lang.org][users],
607 or on [StackOverflow][so].
609 Participate in the [RFC process](https://github.com/rust-lang/rfcs).
611 Find a [requested community library][community-library], build it, and publish
612 it to [Crates.io](http://crates.io). Easier said than done, but very, very
615 [pound-rust]: http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust
616 [users]: https://users.rust-lang.org/
617 [so]: http://stackoverflow.com/questions/tagged/rust
618 [community-library]: https://github.com/rust-lang/rfcs/labels/A-community-library
620 ## Helpful Links and Information
621 [helpful-info]: #helpful-info
623 For people new to Rust, and just starting to contribute, or even for
624 more seasoned developers, some useful places to look for information
627 * The [rustc guide] contains information about how various parts of the compiler work
628 * [Rust Forge][rustforge] contains additional documentation, including write-ups of how to achieve common tasks
629 * The [Rust Internals forum][rif], a place to ask questions and
630 discuss Rust's internals
631 * The [generated documentation for rust's compiler][gdfrustc]
632 * The [rust reference][rr], even though it doesn't specifically talk about Rust's internals, it's a great resource nonetheless
633 * Although out of date, [Tom Lee's great blog article][tlgba] is very helpful
634 * [rustaceans.org][ro] is helpful, but mostly dedicated to IRC
635 * The [Rust Compiler Testing Docs][rctd]
636 * For @bors, [this cheat sheet][cheatsheet] is helpful (Remember to replace `@homu` with `@bors` in the commands that you use.)
637 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
638 * Don't be afraid to ask! The Rust community is friendly and helpful.
640 [rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
641 [gdfrustc]: http://manishearth.github.io/rust-internals-docs/rustc/
642 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
643 [rif]: http://internals.rust-lang.org
644 [rr]: https://doc.rust-lang.org/book/README.html
645 [rustforge]: https://forge.rust-lang.org/
646 [tlgba]: http://tomlee.co/2014/04/a-more-detailed-tour-of-the-rust-compiler/
647 [ro]: http://www.rustaceans.org/
648 [rctd]: ./src/test/COMPILER_TESTS.md
649 [cheatsheet]: https://buildbot2.rust-lang.org/homu/