Causing stack overflow by calling to_string in Display trait implementation

[lukaseller]

As a mentor on exercism.io I came across the following code:

impl Display for Clock {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
        write!(f, "{}", self.to_string())
    }
}

This causes a stack overflow: The reason for that being that to_string is automatically implemented by the Display trait - which generates a loop. At least that is my explaination.

Is there a way for the compiler to catch mistakes like this? This is actually the first time i really saw someone generate a runtime error with safe rust (except for panics of course).

[jonas-schievink]

#57965 would fix this

[jonas-schievink]

This also looks like a direct duplicate of #45838, so closing in favor of that