Rust conversion of hex rgb strings to their components

hex_colours.rs

use crate::RGBError::WrongLength;
use std::num::ParseIntError;
use std::str::FromStr;

#[derive(Debug)]
struct RGB {
    red: u8,
    green: u8,
    blue: u8,
}

#[derive(Debug)]
enum RGBError {
    WrongDigits,
    WrongLength,
}

impl From<ParseIntError> for RGBError {
    fn from(_: ParseIntError) -> Self {
        RGBError::WrongDigits
    }
}

impl FromStr for RGB {
    type Err = RGBError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let ignore_hash = s.strip_prefix('#').unwrap_or(s);

        if ignore_hash.len() != 6 {
            return Err(WrongLength);
        }

        let hex_byte = u32::from_str_radix(ignore_hash, 16)?;
        let red: u8 = (hex_byte >> 16) as u8;
        let green: u8 = (hex_byte >> 8) as u8;
        let blue: u8 = hex_byte as u8;

        Ok(RGB { red, green, blue })
    }
}

fn main() {
    // Directly
    let rgb = RGB::from_str("FFFFFF").unwrap();
    println!("Red: {}, Green: {}, Blue: {}", rgb.red, rgb.green, rgb.blue);

    // Via parse
    let rgb: RGB = ("#010203").parse().unwrap();
    println!("Red: {}, Green: {}, Blue: {}", rgb.red, rgb.green, rgb.blue);

    let rgb = RGB::from_str("toolong");
    println!("{:?}", rgb);

    let rgb = RGB::from_str("01020z");
    println!("{:?}", rgb);
}

Output

Red: 255, Green: 255, Blue: 255
Red: 1, Green: 2, Blue: 3
Err(WrongLength)
Err(WrongDigits)