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Shea Newton 7af0c67855
Extend indexing_slicing lint
Hey there clippy team! I've made some assumptions in this PR and I'm not at all certain they'll look like the right approach to you. I'm looking forward to any feedback or revision requests you have, thanks!

    Prior to this commit the `indexing_slicing` lint was limited to indexing/slicing operations on arrays. This meant that the scope of a really useful lint didn't include vectors. In order to include vectors in the `indexing_slicing` lint a few steps were taken.

    The `array_indexing.rs` source file in `clippy_lints` was renamed to `indexing_slicing.rs` to more accurately reflect the lint's new scope. The `OUT_OF_BOUNDS_INDEXING` lint persists through these changes so if we can know that a constant index or slice on an array is in bounds no lint is triggered.

    The `array_indexing` tests in the `tests/ui` directory were also extended and moved to `indexing_slicing.rs` and `indexing_slicing.stderr`.

    The `indexing_slicing` lint was moved to the `clippy_pedantic` lint group.

    A specific "Consider using" string was added to each of the `indexing_slicing` lint reports.

    At least one of the test scenarios might look peculiar and I'll leave it up to y'all to decide if it's palatable. It's the result of indexing the array `x` after `let x = [1, 2, 3, 4];`

    ```
    error: slicing may panic. Consider using `.get(..n)`or `.get_mut(..n)`instead
      --> $DIR/indexing_slicing.rs:23:6
       |
    23 |     &x[0..][..3];
       |      ^^^^^^^^^^^
    ```

    The error string reports only on the second half's range-to, because the range-from is in bounds!

    Again, thanks for taking a look.

    Closes #2536
2018-06-19 16:27:08 +00:00
.github Add exec bit, add set -ex to ci test files 2018-05-16 18:55:21 +02:00
ci Update integration test 2018-05-30 11:20:34 +02:00
clippy_lints Extend indexing_slicing lint 2018-06-19 16:27:08 +00:00
clippy_workspace_tests Fix logic that determines closest parent crate when invoked from a subdirectory. 2017-07-27 00:04:17 -07:00
mini-macro rustup 2018-04-27 14:00:43 +02:00
src Cleanup of driver code 2018-06-07 22:13:24 +02:00
tests Extend indexing_slicing lint 2018-06-19 16:27:08 +00:00
util Fix typo in lint dump script 2018-06-15 17:45:52 +02:00
.editorconfig Add EditorConfig 2016-07-15 13:08:21 +02:00
.gitignore Patterns, locals and matches for author lint 2018-05-11 19:05:34 +02:00
.remarkrc.json use .remarkrc.json for travis 2016-05-06 16:13:05 +02:00
.travis.yml only install remark if not on an integration build to avoid ddosing npm 2018-05-29 21:28:52 +02:00
appveyor.yml Don't run cargo clippy on appveyor 2018-01-19 13:14:44 +01:00
build.rs Format code 2018-05-22 10:21:42 +02:00
Cargo.toml Version bump 2018-06-19 09:56:37 +02:00
CHANGELOG.md Version bump 2018-06-19 09:56:37 +02:00
CONTRIBUTING.md Use the new scoped tool attributes 2018-05-19 14:04:57 +02:00
LICENSE Create LICENSE 2017-07-13 14:10:30 -07:00
min_version.txt Version bump 2018-06-19 09:56:37 +02:00
pre_publish.sh Sort entries in pre-publish script 2017-05-19 17:02:29 +02:00
publish.files CHANGELOG is ordered after Cargo 2017-06-16 18:44:41 +02:00
PUBLISH.md fix docs 2017-09-23 13:36:40 -07:00
README.md Version bump 2018-06-18 09:56:58 +02:00
rust-update Tiny typo in rust-update script 2018-06-07 17:47:11 +01:00
rustfmt.toml Remove removed rustfmt options 2018-05-09 15:31:52 +02:00

rust-clippy

Build Status Windows build status Current Version License: MPL-2.0

A collection of lints to catch common mistakes and improve your Rust code.

There are 268 lints included in this crate!

We have a bunch of lint categories to allow you to choose how much clippy is supposed to annoy help you:

  • clippy (everything that has no false positives)
  • clippy_pedantic (everything)
  • clippy_nursery (new lints that aren't quite ready yet)
  • clippy_style (code that should be written in a more idiomatic way)
  • clippy_complexity (code that does something simple but in a complex way)
  • clippy_perf (code that can be written in a faster way)
  • clippy_cargo (checks against the cargo manifest)
  • clippy_correctness (code that is just outright wrong or very very useless)

More to come, please file an issue if you have ideas!

Table of contents:

Usage

Since this is a tool for helping the developer of a library or application write better code, it is recommended not to include clippy as a hard dependency. Options include using it as an optional dependency, as a cargo subcommand, or as an included feature during build. All of these options are detailed below.

As a general rule clippy will only work with the latest Rust nightly for now.

To install Rust nightly, the recommended way is to use rustup:

rustup install nightly

As a cargo subcommand (cargo clippy)

One way to use clippy is by installing clippy through cargo as a cargo subcommand.

cargo +nightly install clippy

(The +nightly is not necessary if your default rustup install is nightly)

Now you can run clippy by invoking cargo +nightly clippy.

To update the subcommand together with the latest nightly use the rust-update script or run:

rustup update nightly
cargo +nightly install --force clippy

In case you are not using rustup, you need to set the environment flag SYSROOT during installation so clippy knows where to find librustc and similar crates.

SYSROOT=/path/to/rustc/sysroot cargo install clippy

Running clippy from the command line without installing it

To have cargo compile your crate with clippy without clippy installation in your code, you can use:

cargo run --bin cargo-clippy --manifest-path=path_to_clippys_Cargo.toml

Note: Be sure that clippy was compiled with the same version of rustc that cargo invokes here!

Configuration

Some lints can be configured in a TOML file named with clippy.toml or .clippy.toml. It contains basic variable = value mapping eg.

blacklisted-names = ["toto", "tata", "titi"]
cyclomatic-complexity-threshold = 30

See the list of lints for more information about which lints can be configured and the meaning of the variables.

To deactivate the “for further information visit lint-link” message you can define the CLIPPY_DISABLE_DOCS_LINKS environment variable.

Allowing/denying lints

You can add options to allow/warn/deny:

  • the whole set of Warn lints using the clippy lint group (#![deny(clippy)])

  • all lints using both the clippy and clippy_pedantic lint groups (#![deny(clippy)], #![deny(clippy_pedantic)]). Note that clippy_pedantic contains some very aggressive lints prone to false positives.

  • only some lints (#![deny(single_match, box_vec)], etc)

  • allow/warn/deny can be limited to a single function or module using #[allow(...)], etc

Note: deny produces errors instead of warnings.

For convenience, cargo clippy automatically defines a cargo-clippy feature. This lets you set lint levels and compile with or without clippy transparently:

#[cfg_attr(feature = "cargo-clippy", allow(needless_lifetimes))]

Updating rustc

Sometimes, rustc moves forward without clippy catching up. Therefore updating rustc may leave clippy a non-functional state until we fix the resulting breakage.

You can use the rust-update script to update rustc only if clippy would also update correctly.

License

Licensed under MPL. If you're having issues with the license, let me know and I'll try to change it to something more permissive.