6399 Lint: is_ascii_digit instead of is_digit

[rajcspsg]

changelog: none

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @ebroto (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[ebroto]

Hi @rajcspsg and welcome to Clippy!

The objective of this issue is to create a lint that detects c.is_digit(10) and c.is_digit(16) and suggests changing that code to c.is_ascii_digit() and c.is_ascii_hexdigit() respectively. After implementing that lint, running clippy will suggest the changes you made to the code manually.

Take a look at the following docs:

• Basics for hacking on Clippy
• Adding a new lint
• Common tools for writing lints

These will help you to get started. In case you have any doubt, you can ask a question on Zulip or in this same PR.

[ebroto]

Also, you can take a look at other PRs that add lints, like #6394, to get an idea of what is needed.

Happy hacking!

[giraffate]

ping from triage @rajcspsg. Do you have any questions on how to proceed here?

[rajcspsg]

@giraffate - I'm facing below issue in my local

    $ cargo test
    error: failed to run `rustc` to learn about target-specific information

    Caused by:
    process didn't exit successfully: `rustc - --crate-name ___ --print=file-names -Zunstable-options --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=cfg` (exit code: 1)
    --- stderr
    error: the option `Z` is only accepted on the nightly compiler

I tried these options -

1. cargo +nightly rustc -- -Z external-macro-backtrace
2. rustup default nightly

Even after I did rustup default nightly I'm seeing the rust version is rustc 1.48.0 (7eac88abb 2020-11-16)
I don't know how to fix this issue. Any idea on this

[giraffate]

@rajcspsg Can you do a rebase? nightly-2020-12-14 is pinned by rust-toolchain file on master branch.
Also, you might look at ${RUSTUP_HOME}/settings.toml to check if you have a override on Clippy repo. rustup override unset might be useful if you had a override.

[ebroto]

According to the triage procedure, I should close this PR as there has been no activity and two weeks have passed since the last ping.

@rajcspsg did @giraffate suggestions help? Can we help you with another issue? Do not hesitate to reopen this in case you are working on it.

[jonboh]

@rustbot label -S-inactive-closed