FN: useless format: formatting PathBuf.display()

[matthiaskrgr]

use std::path::PathBuf;

fn main() {
    let x = PathBuf::from("/bar/foo/qux");
    let y = format!("{}", x.display()); // can just be   let y = x.display();
    println!("{}", y);
}

[oli-obk]

We could generally lint the use of the result of format! as an argumennt in another formatting

[matthiaskrgr]

Mmh, this might be tricky.

IIRC it is faster to have a single print() than multiple ones (due to less syscalls) so when I need to print large strings, I usually construct them first with a/multiple format!()s and then print a single String in the end.

[oli-obk]

sure, but you don't need to format!, you can just format_args! it and print that at the end without ever allocating a String

[matthiaskrgr]

Ah, I'll have to read up on this!

[adilhasan]

Hello, I stumbled upon a similar problem and figured out a way to print a PathBuf. Here's my (shaky) reasoning:

• I can convert from PathBuf to a str using the to_str function.
• The to_str function returns an Option str, so I need to unwrap it to get the str
• Then I can print out the path:
  println!("path {}", x.to_str().unwrap());