An example of a failing parse error kind implementation

Cargo.toml

[package]
edition = '2018'
name = "wtf_nom"
version = "0.0.1-dev"
authors = ["Andreas Fuchs <asf@boinkor.net>"]
license = "MIT"

[dependencies]
nom = "4.2.3"

lib.rs

use nom::*;

#[derive(Debug, PartialEq, Clone)]
pub enum ParseErrorKind {
    Bcrypt,

    /// An unexpected parse error, indicates a bug in the htpasswd crate
    Unknown,
}

impl From<u32> for ParseErrorKind {
    fn from(f: u32) -> Self {
        ParseErrorKind::Unknown
    }
}

named!(bcrypt_pw<&str, String, ParseErrorKind>,
       return_error!(ErrorKind::Custom(ParseErrorKind::Bcrypt),
                     do_parse!(
                               peek!(alt_complete!(tag!("$2a$") | tag!("$2y$") | tag!("$2b$"))) >>
                               pw: not_line_ending >>
                               (pw.to_string())
                     ))
);