format!("{}", X) -> X.to_string()

[mark-summerfield]

What it does

Since many types support to_string() if format! is being used just to produce a string version then surely calling to_string() is better?

Lint Name

Convert an item to a string

Category

style

Advantage

I assume that this would be more efficient. It looks nicer too.

Drawbacks

No response

Example

    let year = Local::today().year();
    let year = if year == 2021 {
        format!("{}", year)
    } else {
        format!("2021-{}", year - 2000)
    };

Could be written as:

    let year = Local::today().year();
    let year = if year == 2021 {
        year.to_string()
    } else {
        format!("2021-{}", year - 2000)
    };

[giraffate]

Do you mean the useless_format lint?

[mark-summerfield]

No, it is different. The useless_format hint is where the X is a string; I'm talking about when it isn't a string but does have a to_string() method, e.g., an i32.

[camsteffen]

Duplicate of #3156