Literal error reporting cleanup
While doing some performance work, I noticed some code duplication in `librustc_parser/lexer/mod.rs`, so I cleaned it up.
This PR is probably best reviewed commit by commit.
I'm not sure what the API stability practices for `librustc_lexer` are. Four public methods in `unescape.rs` can be removed, but two are used by clippy, so I left them in for now.
I could open a PR for Rust-Analyzer when this one lands.
But how do I open a PR for clippy? (Git submodules are frustrating to work with)
rustc_driver: factor out computing the exit code
In a recent Miri PR I [added a convenience wrapper](https://github.com/rust-lang/miri/pull/1405/files#diff-c3d602c5c8035a16699ce9c015bfeceaR125) around `catch_fatal_errors` and `run_compiler` that @oli-obk suggested I could upstream. However, after seeing what could be shared between `rustc_driver::main`, clippy and Miri, really the only thing I found is computing the exit code -- so that's what this PR does.
What prevents using the Miri convenience function in `rustc_driver::main` and clippy is that they do extra work inside `catch_fatal_errors`, and while I could abstract that away, clippy actually *computes the callbacks* inside there, and I fond no good way to abstract that and thus gave up. Maybe the clippy thing could be moved out, I am not sure if it ever can actually raise a `FatalErrorMarker` -- someone more knowledgeable in clippy would have to do that.
Fixed incorrect suggestion of `clone_double_ref` lint
- Added `<_>` to suggestion
- Changed help message
- Added new tests
Closes#5494
changelog: Improve suggestion of [`clone_double_ref`]
New lint `match_vec_item`
Added new lint to warn a match on index item which can panic. It's always better to use `get(..)` instead.
Closes#5500
changelog: New lint `match_on_vec_items`
Implement mismatched_target_os lint
I've extended the check suggested in the issue to all the currently supported operating systems instead of limiting it to `linux` and `macos`, let me know if we want to do this.
Also, I've restored the text `There are over XXX lints ...` in the README as it was matched against by `cargo dev new_lint`.
changelog: Added `mismatched_target_os` lint to warn when an operating system is used in target family position in a #[cfg] attribute
Closes#3949
- Show just one error message with multiple suggestions in case of
using multiple times an OS in target family position
- Only suggest #[cfg(unix)] when the OS is in the Unix family
- Test all the operating systems
Don't trigger while_let_on_iterator when the iterator is recreated every iteration
r? @phansch
Fixes#1654
changelog: Fix false positive in [`while_let_on_iterator`]
