Why is this an issue?

Recursive calls in formatting trait implementations (e.g., Display) will lead to infinite recursion and a stack overflow.

Code examples

Noncompliant code example

use std::fmt;

struct Structure(i32);
impl fmt::Display for Structure {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.to_string()) // Noncompliant
    }
}

Compliant solution

use std::fmt;

struct Structure(i32);
impl fmt::Display for Structure {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.0) // Compliant
    }
}

Resources

Documentation

• Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#recursive_format_impl