FN useless format: struct with fmt::Display and format!() ?

[matthiaskrgr]

struct StructX {
    x: u32,
}

impl std::fmt::Display for StructX {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "hello {}", self.x)?;
        Ok(())
    }
}

/*
 * note that we have 
 * impl<T> ToString for T
 *    where T: Display + ?Sized
 * which means to_string() will be available for StructX
 */

fn main() {
    let y = StructX { x: 4, };
    let s = format!("{}", y);
    // due to the impl, the above line can be
    // let s = y.to_string();
    println!("{}", s.len());
}

In godbolt, format!("{}", y) and y.to_string() didn't seem to differ, yet I think that .to_string() is a bit clearer since we don't perform any special formatting here.
Thoughts?

[camsteffen]

Marking as pedantic for reasons discussed in #3753