use crate::Message;use bstr::BString;use std::borrow::Cow;use std::fmt::{Debug, Display, Formatter}; /// An error occurred when validating input.////// This can happen explicitly, or as part of parsing, for example.#[derive(Debug)]pub struct ValidationError {    /// The error message.    pub message: Cow<'static, str>,    /// The input or portion of the input that wasn't valid.    pub input: Option<BString>,} /// Lifecycleimpl ValidationError {    /// Create a new error with `message` and `input`. The `input` is displayed with debug formatting to not hide whitespace related issues.    pub fn new_with_input(message: impl Into<Cow<'static, str>>, input: impl Into<BString>) -> Self {        ValidationError {            message: message.into(),            input: Some(input.into()),        }    }     /// Create a new instance that displays the given `message`.    pub fn new(message: impl Into<Cow<'static, str>>) -> Self {        ValidationError {            message: message.into(),            input: None,        }    }} impl Display for ValidationError {    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {        match &self.input {            None => f.write_str(self.message.as_ref()),            Some(input) => {                write!(f, "{}: {input:?}", self.message)            }        }    }} impl std::error::Error for ValidationError {} impl From<Message> for ValidationError {    fn from(Message(msg): Message) -> Self {        ValidationError::new(msg)    }} impl From<String> for ValidationError {    fn from(msg: String) -> Self {        ValidationError::new(msg)    }} impl From<&'static str> for ValidationError {    fn from(msg: &'static str) -> Self {        ValidationError::new(msg)    }}