New lint: iter_next_slice
Hello, this is a work-in-progress PR for issue: https://github.com/rust-lang/rust-clippy/issues/5572
I have implemented lint to replace `iter().next()` for `slice[index..]` and `array` with `get(index)` and `get(0)` respectively. However since I made a lot of changes, I would like to request some feedback before continuing so that I could fix mistakes.
Thank you!
---
changelog: implement `iter_next_slice` lint and test, and modify `needless_continues`, `for_loop_over_options_result` UI tests since they have `iter().next()`
Add regression test for endless loop / update `pulldown_cmark`
Closes#4917
This was fixed in pulldown_cmark 0.7.1, specifically raphlinus/pulldown-cmark#438
changelog: none
cargo-ui tests: check that <dir>/src exists before processing test
I forgot that I had fixed this in a PR I closed some days ago (#5643).
Before this change, cargo UI tests could fail when switching between branches if the previous branch had a test that the current branch does not have. The directory is not removed when switching because an ignored `Cargo.lock` file exists, and the code was trying to reach `$DIR/src` unconditionally.
This change will just skip a directory that has no `src` subdirectory.
changelog: none
Rework suggestion generation of `unit_arg` lint
Found this bug while running `cargo fix --clippy` on quite a big codebase:
This would replace something like:
```rust
Some(fn_that_actually_does_something(&a, b))
```
with
```rust
Some(())
```
which obviously suppresses side effects.
Since pretty much every expression could have side effects, I think making this suggestion `MaybeIncorrect` is the best thing to do here.
A correct suggestion would be:
```rust
fn_that_actually_does_something(&a, b);
Some(())
```
Somehow the suggestion is not correctly applied to the arguments, when more than one argument is a unit value. I have to look into this a little more, though.
changelog: Fixes suggestion of `unit_arg` lint, so that it suggests semantic equivalent code
Fixes#4741
Increase cargo_metadata version to 0.9.1
`clippy_lints` makes use of `dep_kinds` on `NodeDep` but this was only
added in versoin 0.9.1. Compiling with 0.9.0 will fail because of this.
changelog: none
len_zero: skip ranges if feature `range_is_empty` is not enabled
If the feature is not enabled, calling `is_empty()` on a range is ambiguous. Moreover, the two possible resolutions are unstable methods, one inherent to the range and the other being part of the `ExactSizeIterator` trait.
Since `len_zero` only checks for existing `is_empty()` inherent methods, we only take into account the `range_is_empty` feature.
Related: https://github.com/rust-lang/rust/issues/48111#issuecomment-445132965
changelog: len_zero: avoid linting ranges without #![feature(range_is_empty)]
Fixes: #3807
cargo_dev: add ra-setup
It takes an absolute path to a rustc repo and adds path-dependencies
that point towards the respective rustc subcrates into the Cargo.tomls of
the clippy and clippy_lints crate.
This allows rustc-analyzer to show proper type annotations etc on rustc-internals inside the clippy repo.
Usage: cargo dev ra-setup /absolute/path/to/rust/
cc https://github.com/rust-analyzer/rust-analyzer/issues/3517
cc https://github.com/rust-lang/rust-clippy/issues/5514
changelog: none
