Lint towards replacing from_str_radix with str::parse when the radix is 10

[booleancoercion]

What it does

The lint suggests replacing e.g. u16::from_str_radix(&string, 10) with string.parse().
(Obviously, it could also be any other primitive with such associated function).

Categories (optional)

• Kind: perhaps this could go in clippy::style.

What is the advantage of the recommended code over the original code?

The resulting code is shorter, easier to read and doesn't involve using 10 as a magic number.

Drawbacks

Using str::parse instead, the user might have to specify types in some cases.

Example

let input: &str = get_input();
let num = u16::from_str_radix(input, 10)?;

Could be written as:

let input: &str = get_input();
let num: u16 = input.parse()?;

(In a more complicated use case, the type of num will probably be inferred.)

[booleancoercion]

If this lint makes sense, I'd like to try implementing it myself!

[xFrednet]

I believe this lint makes sense. We can easily change its category to clippy::pedantic if it's a lint that is seen to be to strict 🙃

clippy::pedantic	lints which are rather strict or might have false positives	allow

You can take this issue up and it seems like you've already found our Zulip. Could you comment @rustbot claim to assign the issue to you? This makes it clearer for others that someone is working on this. You can also unassign yourself at any point if you don't want to finish the lint.

---

And welcome to clippy 🙃

[xFrednet]

@rustbot label +A-lint +T-middle

[booleancoercion]

Thanks! Yeah I'll assign it to myself.
Perhaps it could have false positives when someone uses a constant for the base that might be changed later I guess

[booleancoercion]

@rustbot claim

[xFrednet]

Thank you 🙃 can also include the @rustbot in a lager comments. I've only put it extra because I forgot it at first 😅

Perhaps it could have false positives when someone uses a constant for the base

This should not be a problem if you only check for the literal 10. HIR references constant values using a path. This means that the lint would not see a constant like this u16::from_str_radix(input, 10)?; but rather as u16::from_str_radix(input, crate::VALUE_RADIX)?;. The actual optimizations and constant replacements are done after Clippy lints the code.

Feel free to ask here or on Zulip if you have any more questions :)