Clippy Book Chapter Updates Reborn: Trait Checking
This PR adds a new chapter to the book: "Trait Checking". No major changes from the source (just some typos, re-phrasing, the usual).
## Notes
- Does not require any other PR to be merged.
- To talk about the whole project, please use the tracking issue for the project #10597 (It also contains a timeline, discussions and more information)
changelog: Add a new "Trait Checking" chapter to the book
Clippy Book Chapter Updates Reborn: Emitting lints
The PR adds a new chapter to the book: "Emitting lints". This time it changed a lot from the old source file.
## Notes
- For discussion about the whole project, please use the tracking issue for the project #10597 (It also contains a timeline, discussions, and more information)
changelog: Add a new "Emitting lints" chapter to the book
r? `@flip1995`
Fix SPEEDTEST instructions and output
* `--nocapture` hasn't been needed anymore since forever (even before `ui_test`)
* the result was dividing by 1000 instead of the number of test runs, giving bogus (but still useful for the purpose) timing results.
changelog: fix SPEEDTEST instructions and output
Add `SPEEDTEST`
In the `master` branch, we currently don't have any way to test the performance of a single lint in changes.
This PR adds `SPEEDTEST`, the environment variable which lets you do a speed test on a lint / category of tests with various configuration options.
Maybe we should merge this with `lintcheck` 🤔
See the book page for more information.
changelog:none
Port clippy away from compiletest to ui_test
Reasons to do this:
* runs completely on stable Rust
* is easier to extend with new features
* has its own dogfood test suite, so changes can be tested in [the `ui_test` repo](https://github.com/oli-obk/ui_test)
* supports dependencies from crates.io without having to manually fiddle with command line flags
* supports `ui-cargo`, `ui`, `ui-toml` out of the box, no need to find and run the tests ourselves
One thing that is a big difference to `compiletest` is that if a test emits *any* error, you need to mark all of them with `//~ ERROR:` annotations. Since many clippy tests did not have annotations, I changed many lints to be `warn` in their test so that only the `stderr` output is tested.
TODO:
* [ ] check that this still works as a subtree in the rustc repo
changelog: none
<!-- changelog_checked -->
Note: at present the latest changes needed for clippy are only available as a git dependency, but I expect to publish a new crates.io version soon
