Merge branch 'master' of github.com:rust-lang/rust-clippy into option_if_let_else

Author: JarredAllen

CONTRIBUTING.md

@@ -8,10 +8,9 @@ something. We appreciate any sort of contributions, and don't want a wall of rul
 
 Clippy welcomes contributions from everyone. There are many ways to contribute to Clippy and the following document
 explains how you can contribute and how to get started.  If you have any questions about contributing or need help with
-anything, feel free to ask questions on issues or visit the `#clippy` IRC channel on `irc.mozilla.org` or meet us in
-`#clippy` on [Discord](https://discord.gg/rust-lang).
+anything, feel free to ask questions on issues or visit the `#clippy` on [Discord].
 
-All contributors are expected to follow the [Rust Code of Conduct](http://www.rust-lang.org/conduct.html).
+All contributors are expected to follow the [Rust Code of Conduct].
 
 * [Getting started](#getting-started)
   * [Finding something to fix/improve](#finding-something-to-fiximprove)
@@ -22,6 +21,9 @@ All contributors are expected to follow the [Rust Code of Conduct](http://www.ru
 * [Bors and Homu](#bors-and-homu)
 * [Contributions](#contributions)
 
+[Discord]: https://discord.gg/rust-lang
+[Rust Code of Conduct]: https://www.rust-lang.org/policies/code-of-conduct
+
 ## Getting started
 
 High level approach:
@@ -36,57 +38,61 @@ High level approach:
 
 All issues on Clippy are mentored, if you want help with a bug just ask @Manishearth, @llogiq, @mcarton or @oli-obk.
 
-Some issues are easier than others. The [`good first issue`](https://github.com/rust-lang/rust-clippy/labels/good%20first%20issue)
-label can be used to find the easy issues. If you want to work on an issue, please leave a comment
-so that we can assign it to you!
+Some issues are easier than others. The [`good first issue`] label can be used to find the easy issues.
+If you want to work on an issue, please leave a comment so that we can assign it to you!
 
-There are also some abandoned PRs, marked with
-[`S-inactive-closed`](https://github.com/rust-lang/rust-clippy/pulls?q=is%3Aclosed+label%3AS-inactive-closed).
+There are also some abandoned PRs, marked with [`S-inactive-closed`].
 Pretty often these PRs are nearly completed and just need some extra steps
 (formatting, addressing review comments, ...) to be merged. If you want to
 complete such a PR, please leave a comment in the PR and open a new one based
 on it.
 
-Issues marked [`T-AST`](https://github.com/rust-lang/rust-clippy/labels/T-AST) involve simple
-matching of the syntax tree structure, and are generally easier than
-[`T-middle`](https://github.com/rust-lang/rust-clippy/labels/T-middle) issues, which involve types
+Issues marked [`T-AST`] involve simple matching of the syntax tree structure,
+and are generally easier than [`T-middle`] issues, which involve types
 and resolved paths.
 
-[`T-AST`](https://github.com/rust-lang/rust-clippy/labels/T-AST) issues will generally need you to match against a
-predefined syntax structure. To figure out how this syntax structure is encoded in the AST, it is recommended to run
-`rustc -Z ast-json` on an example of the structure and compare with the [nodes in the AST
-docs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast). Usually the lint will end up to be a nested series of
-matches and ifs, [like
-so](https://github.com/rust-lang/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
+[`T-AST`] issues will generally need you to match against a predefined syntax structure.
+To figure out how this syntax structure is encoded in the AST, it is recommended to run
+`rustc -Z ast-json` on an example of the structure and compare with the [nodes in the AST docs].
+Usually the lint will end up to be a nested series of matches and ifs, [like so].
 
-[`E-medium`](https://github.com/rust-lang/rust-clippy/labels/E-medium) issues are generally
-pretty easy too, though it's recommended you work on an E-easy issue first. They are mostly classified
-as `E-medium`, since they might be somewhat involved code wise, but not difficult per-se.
+[`E-medium`] issues are generally pretty easy too, though it's recommended you work on an E-easy issue first.
+They are mostly classified as [`E-medium`], since they might be somewhat involved code wise,
+but not difficult per-se.
 
-[`T-middle`](https://github.com/rust-lang/rust-clippy/labels/T-middle) issues can
-be more involved and require verifying types. The
-[`ty`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty) module contains a
+[`T-middle`] issues can be more involved and require verifying types. The [`ty`] module contains a
 lot of methods that are useful, though one of the most useful would be `expr_ty` (gives the type of
 an AST expression). `match_def_path()` in Clippy's `utils` module can also be useful.
 
+[`good first issue`]: https://github.com/rust-lang/rust-clippy/labels/good%20first%20issue
+[`S-inactive-closed`]: https://github.com/rust-lang/rust-clippy/pulls?q=is%3Aclosed+label%3AS-inactive-closed
+[`T-AST`]: https://github.com/rust-lang/rust-clippy/labels/T-AST
+[`T-middle`]: https://github.com/rust-lang/rust-clippy/labels/T-middle
+[`E-medium`]: https://github.com/rust-lang/rust-clippy/labels/E-medium
+[`ty`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty
+[nodes in the AST docs]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/
+[like so]: https://github.com/rust-lang/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34
+
 ## Writing code
 
-Have a look at the [docs for writing lints](doc/adding_lints.md) for more details. [Llogiq's blog post on
-lints](https://llogiq.github.io/2015/06/04/workflows.html) is also a nice primer to lint-writing, though it does get
-into advanced stuff and may be a bit outdated.
+Have a look at the [docs for writing lints][adding_lints] for more details. [Llogiq's blog post on lints]
+is also a nice primer to lint-writing, though it does get into advanced stuff and may be a bit outdated.
 
 If you want to add a new lint or change existing ones apart from bugfixing, it's
 also a good idea to give the [stability guarantees][rfc_stability] and
 [lint categories][rfc_lint_cats] sections of the [Clippy 1.0 RFC][clippy_rfc] a
 quick read.
 
-## How Clippy works
+[adding_lints]: https://github.com/rust-lang/rust-clippy/blob/master/doc/adding_lints.md
+[Llogiq's blog post on lints]: https://llogiq.github.io/2015/06/04/workflows.html
+[clippy_rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md
+[rfc_stability]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#stability-guarantees
+[rfc_lint_cats]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#lint-audit-and-categories
 
-Clippy is a [rustc compiler plugin][compiler_plugin]. The main entry point is at [`src/lib.rs`][main_entry]. In there,
-the lint registration is delegated to the [`clippy_lints`][lint_crate] crate.
+## How Clippy works
 
-[`clippy_lints/src/lib.rs`][lint_crate_entry] imports all the different lint modules and registers them with the rustc
-plugin registry. For example, the [`else_if_without_else`][else_if_without_else] lint is registered like this:
+[`clippy_lints/src/lib.rs`][lint_crate_entry] imports all the different lint modules and registers in the [`LintStore`].
+For example, the [`else_if_without_else`][else_if_without_else] lint is registered like this:
 
 ```rust
 // ./clippy_lints/src/lib.rs
@@ -95,25 +101,24 @@ plugin registry. For example, the [`else_if_without_else`][else_if_without_else]
 pub mod else_if_without_else;
 // ...
 
-pub fn register_plugins(reg: &mut rustc_driver::plugin::Registry) {
+pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &Conf) {
     // ...
-    reg.register_early_lint_pass(box else_if_without_else::ElseIfWithoutElse);
+    store.register_early_pass(|| box else_if_without_else::ElseIfWithoutElse);
     // ...
 
-    reg.register_lint_group("clippy::restriction", vec![
+    store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         // ...
-        else_if_without_else::ELSE_IF_WITHOUT_ELSE,
+        LintId::of(&else_if_without_else::ELSE_IF_WITHOUT_ELSE),
         // ...
     ]);
 }
 ```
 
-The [`plugin::PluginRegistry`][plugin_registry] provides two methods to register lints:
-[register_early_lint_pass][reg_early_lint_pass] and [register_late_lint_pass][reg_late_lint_pass].  Both take an object
+The [`rustc_lint::LintStore`][`LintStore`] provides two methods to register lints:
+[register_early_pass][reg_early_pass] and [register_late_pass][reg_late_pass]. Both take an object
 that implements an [`EarlyLintPass`][early_lint_pass] or [`LateLintPass`][late_lint_pass] respectively. This is done in
 every single lint. It's worth noting that the majority of `clippy_lints/src/lib.rs` is autogenerated by `cargo dev
-update_lints` and you don't have to add anything by hand. When you are writing your own lint, you can use that script to
-save you some time.
+update_lints`. When you are writing your own lint, you can use that script to save you some time.
 
 ```rust
 // ./clippy_lints/src/else_if_without_else.rs
@@ -135,8 +140,16 @@ The difference between `EarlyLintPass` and `LateLintPass` is that the methods of
 AST information. The methods of the `LateLintPass` trait are executed after type checking and contain type information
 via the `LateContext` parameter.
 
-That's why the `else_if_without_else` example uses the `register_early_lint_pass` function. Because the [actual lint
-logic][else_if_without_else] does not depend on any type information.
+That's why the `else_if_without_else` example uses the `register_early_pass` function. Because the
+[actual lint logic][else_if_without_else] does not depend on any type information.
+
+[lint_crate_entry]: https://github.com/rust-lang/rust-clippy/blob/master/clippy_lints/src/lib.rs
+[else_if_without_else]: https://github.com/rust-lang/rust-clippy/blob/4253aa7137cb7378acc96133c787e49a345c2b3c/clippy_lints/src/else_if_without_else.rs
+[`LintStore`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html
+[reg_early_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html#method.register_early_pass
+[reg_late_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html#method.register_late_pass
+[early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/trait.EarlyLintPass.html
+[late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/trait.LateLintPass.html
 
 ## Fixing build failures caused by Rust
 
@@ -145,8 +158,9 @@ the times we have to adapt to the changes and only very rarely there's an actual
 caused by Rust updates, can be a good way to learn about Rust internals.
 
 In order to find out why Clippy does not work properly with a new Rust commit, you can use the [rust-toolstate commit
-history][toolstate_commit_history].  You will then have to look for the last commit that contains `test-pass ->
-build-fail` or `test-pass` -> `test-fail` for the `clippy-driver` component. [Here][toolstate_commit] is an example.
+history][toolstate_commit_history]. You will then have to look for the last commit that contains
+`test-pass -> build-fail` or `test-pass -> test-fail` for the `clippy-driver` component.
+[Here][toolstate_commit] is an example.
 
 The commit message contains a link to the PR. The PRs are usually small enough to discover the breaking API change and
 if they are bigger, they likely include some discussion that may help you to fix Clippy.
@@ -158,14 +172,8 @@ If you decide to make Clippy work again with a Rust commit that breaks it,
 you probably want to install the latest Rust from master locally and run Clippy
 using that version of Rust.
 
-You can use [rustup-toolchain-install-master][rtim] to do that:
-
-```bash
-cargo install rustup-toolchain-install-master
-rustup-toolchain-install-master --force -n master -c rustc-dev
-rustup override set master
-cargo test
-```
+You can set up the master toolchain by running `./setup-toolchain.sh`. That script will install
+[rustup-toolchain-install-master][rtim] and master toolchain, then run `rustup override set master`.
 
 After fixing the build failure on this repository, we can submit a pull request
 to [`rust-lang/rust`] to fix the toolstate.
@@ -182,6 +190,12 @@ git commit -m "Update Clippy"
 # Open a PR in rust-lang/rust
 ```
 
+[rustup_component_history]: https://rust-lang.github.io/rustup-components-history
+[toolstate_commit_history]: https://github.com/rust-lang-nursery/rust-toolstate/commits/master
+[toolstate_commit]: https://github.com/rust-lang-nursery/rust-toolstate/commit/aad74d8294e198a7cf8ac81a91aebb7f3bbcf727
+[rtim]: https://github.com/kennytm/rustup-toolchain-install-master
+[`rust-lang/rust`]: https://github.com/rust-lang/rust
+
 ## Issue and PR triage
 
 Clippy is following the [Rust triage procedure][triage] for issues and pull
@@ -206,39 +220,22 @@ You can find the Clippy bors queue [here][homu_queue].
 If you have @bors permissions, you can find an overview of the available
 commands [here][homu_instructions].
 
+[triage]: https://forge.rust-lang.org/triage-procedure.html
+[l-crash]: https://github.com/rust-lang/rust-clippy/labels/L-crash%20%3Aboom%3A
+[l-bug]: https://github.com/rust-lang/rust-clippy/labels/L-bug%20%3Abeetle%3A
+[homu]: https://github.com/rust-lang/homu
+[homu_instructions]: https://buildbot2.rust-lang.org/homu/
+[homu_queue]: https://buildbot2.rust-lang.org/homu/queue/clippy
 
 ## Contributions
 
 Contributions to Clippy should be made in the form of GitHub pull requests. Each pull request will
 be reviewed by a core contributor (someone with permission to land patches) and either landed in the
 main tree or given feedback for changes that would be required.
 
-All code in this repository is under the [Apache-2.0](http://www.apache.org/licenses/LICENSE-2.0>)
-or the [MIT](http://opensource.org/licenses/MIT) license.
+All code in this repository is under the [Apache-2.0] or the [MIT] license.
 
 <!-- adapted from https://github.com/servo/servo/blob/master/CONTRIBUTING.md -->
 
-[main_entry]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/src/lib.rs#L14
-[lint_crate]: https://github.com/rust-lang/rust-clippy/tree/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src
-[lint_crate_entry]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/lib.rs
-[else_if_without_else]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/else_if_without_else.rs
-[compiler_plugin]: https://doc.rust-lang.org/unstable-book/language-features/plugin.html#lint-plugins
-[plugin_registry]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html
-[reg_early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html#method.register_early_lint_pass
-[reg_late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html#method.register_late_lint_pass
-[early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/lint/trait.EarlyLintPass.html
-[late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/lint/trait.LateLintPass.html
-[toolstate_commit_history]: https://github.com/rust-lang-nursery/rust-toolstate/commits/master
-[toolstate_commit]: https://github.com/rust-lang-nursery/rust-toolstate/commit/6ce0459f6bfa7c528ae1886492a3e0b5ef0ee547
-[rtim]: https://github.com/kennytm/rustup-toolchain-install-master
-[rustup_component_history]: https://mexus.github.io/rustup-components-history
-[clippy_rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md
-[rfc_stability]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#stability-guarantees
-[rfc_lint_cats]: https://github.com/rust-lang/rfcs/blob/master/text/2476-clippy-uno.md#lint-audit-and-categories
-[triage]: https://forge.rust-lang.org/triage-procedure.html
-[l-crash]: https://github.com/rust-lang/rust-clippy/labels/L-crash%20%3Aboom%3A
-[l-bug]: https://github.com/rust-lang/rust-clippy/labels/L-bug%20%3Abeetle%3A
-[homu]: https://github.com/servo/homu
-[homu_instructions]: https://buildbot2.rust-lang.org/homu/
-[homu_queue]: https://buildbot2.rust-lang.org/homu/queue/clippy
-[`rust-lang/rust`]: https://github.com/rust-lang/rust
+[Apache-2.0]: https://www.apache.org/licenses/LICENSE-2.0
+[MIT]: https://opensource.org/licenses/MIT

clippy_lints/src/doc.rs

@@ -367,13 +367,16 @@ fn check_attrs<'a>(cx: &LateContext<'_, '_>, valid_idents: &FxHashSet<String>, a
     check_doc(cx, valid_idents, events, &spans)
 }
 
+const RUST_CODE: &[&str] = &["rust", "no_run", "should_panic", "compile_fail", "edition2018"];
+
 fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize>)>>(
     cx: &LateContext<'_, '_>,
     valid_idents: &FxHashSet<String>,
     events: Events,
     spans: &[(usize, Span)],
 ) -> DocHeaders {
     // true if a safety header was found
+    use pulldown_cmark::CodeBlockKind;
     use pulldown_cmark::Event::{
         Code, End, FootnoteReference, HardBreak, Html, Rule, SoftBreak, Start, TaskListMarker, Text,
     };
@@ -386,11 +389,20 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
     let mut in_code = false;
     let mut in_link = None;
     let mut in_heading = false;
-
+    let mut is_rust = false;
     for (event, range) in events {
         match event {
-            Start(CodeBlock(_)) => in_code = true,
-            End(CodeBlock(_)) => in_code = false,
+            Start(CodeBlock(ref kind)) => {
+                in_code = true;
+                if let CodeBlockKind::Fenced(lang) = kind {
+                    is_rust =
+                        lang.is_empty() || !lang.contains("ignore") && lang.split(',').any(|i| RUST_CODE.contains(&i));
+                }
+            },
+            End(CodeBlock(_)) => {
+                in_code = false;
+                is_rust = false;
+            },
             Start(Link(_, url, _)) => in_link = Some(url),
             End(Link(..)) => in_link = None,
             Start(Heading(_)) => in_heading = true,
@@ -413,7 +425,9 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
                 };
                 let (begin, span) = spans[index];
                 if in_code {
-                    check_code(cx, &text, span);
+                    if is_rust {
+                        check_code(cx, &text, span);
+                    }
                 } else {
                     // Adjust for the beginning of the current `Event`
                     let span = span.with_lo(span.lo() + BytePos::from_usize(range.start - begin));