use core::fmt::{Debug, Display};
use alloc::{boxed::Box, fmt, string::String};
#[allow(dead_code)]
pub trait Error: Debug + Display {
fn source(&self) -> Option<&(dyn Error + 'static)> {
None
}
#[deprecated(since = "1.42.0", note = "use the Display impl or to_string()")]
fn description(&self) -> &str {
"description() is deprecated; use Display"
}
#[deprecated(
since = "1.33.0",
note = "replaced by Error::source, which can support downcasting"
)]
#[allow(missing_docs)]
fn cause(&self) -> Option<&dyn Error> {
self.source()
}
}
impl<'a, T: Error + ?Sized> Error for &'a T {
#[allow(deprecated, deprecated_in_future)]
fn description(&self) -> &str {
Error::description(&**self)
}
#[allow(deprecated)]
fn cause(&self) -> Option<&dyn Error> {
Error::cause(&**self)
}
fn source(&self) -> Option<&(dyn Error + 'static)> {
Error::source(&**self)
}
}
impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
fn from(err: E) -> Box<dyn Error + 'a> {
Box::new(err)
}
}
impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> {
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> {
Box::new(err)
}
}
impl<'a> From<String> for Box<dyn Error + Send + Sync + 'a> {
#[inline]
fn from(err: String) -> Box<dyn Error + Send + Sync + 'a> {
struct StringError(String);
impl Error for StringError {
#[allow(deprecated)]
fn description(&self) -> &str {
&self.0
}
}
impl fmt::Display for StringError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.0, f)
}
}
impl fmt::Debug for StringError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.0, f)
}
}
Box::new(StringError(err))
}
}
impl<'a> From<String> for Box<dyn Error + 'a> {
fn from(str_err: String) -> Box<dyn Error + 'a> {
let err1: Box<dyn Error + Send + Sync> = From::from(str_err);
let err2: Box<dyn Error> = err1;
err2
}
}
impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
#[inline]
fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> {
From::from(String::from(err))
}
}
impl<'a> From<&str> for Box<dyn Error + 'a> {
fn from(err: &str) -> Box<dyn Error + 'a> {
From::from(String::from(err))
}
}
impl<T: Error> Error for Box<T> {
#[allow(deprecated, deprecated_in_future)]
fn description(&self) -> &str {
Error::description(&**self)
}
#[allow(deprecated)]
fn cause(&self) -> Option<&dyn Error> {
Error::cause(&**self)
}
fn source(&self) -> Option<&(dyn Error + 'static)> {
Error::source(&**self)
}
}