Fn fmt calls itself recursively. How to stop?

[StevenLwcz]

use std::fmt;
 
enum LiteralInfo {
    String(String),
    Integer(i32),
    Float(f32),
    Long(i64),
    Double(f64),
}

impl fmt::Display for LiteralInfo {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Literal {} ", self )
    }
}   
    
fn main() {
     println!("main");
     let i = LiteralInfo::Integer(42);
     println!("{}", i);
     let i = LiteralInfo::String("Hello".to_string());
     println!("{}", i);
} 

It looks such an innocent program but I was a bit surprised that I ended up with stack overflow errors.
The format specifier in fn mut is calling fn mut again. What is the best way to solve this? Thanks.

[jofas]

I'd unpack your enum inside fmt:

use std::fmt;
 
enum LiteralInfo {
    String(String),
    Integer(i32),
    Float(f32),
    Long(i64),
    Double(f64),
}

impl fmt::Display for LiteralInfo {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Self::String(s) => write!(f, "Literal {s} "),
            Self::Integer(i) => write!(f, "Literal {i}"),
            _ => write!(f, "unimplemented"),
        }
    }
}   
    
fn main() {
     println!("main");
     let i = LiteralInfo::Integer(42);
     println!("{}", i);
     let i = LiteralInfo::String("Hello".to_string());
     println!("{}", i);
     let i = LiteralInfo::Double(0.);
     println!("{}", i);
}

Playground.

[StevenLwcz]

Of course! Thank you.