#[cfg(test)]
mod tests;
-#[cfg(bootstrap)]
-use core::array;
-#[cfg(bootstrap)]
-use core::convert::Infallible;
-
-#[cfg(bootstrap)]
-use crate::alloc::{AllocError, LayoutError};
-#[cfg(bootstrap)]
-use crate::any::Demand;
-#[cfg(bootstrap)]
-use crate::any::{Provider, TypeId};
use crate::backtrace::Backtrace;
-#[cfg(bootstrap)]
-use crate::borrow::Cow;
-#[cfg(bootstrap)]
-use crate::cell;
-#[cfg(bootstrap)]
-use crate::char;
-#[cfg(bootstrap)]
-use crate::fmt::Debug;
-#[cfg(bootstrap)]
-use crate::fmt::Display;
use crate::fmt::{self, Write};
-#[cfg(bootstrap)]
-use crate::io;
-#[cfg(bootstrap)]
-use crate::mem::transmute;
-#[cfg(bootstrap)]
-use crate::num;
-#[cfg(bootstrap)]
-use crate::str;
-#[cfg(bootstrap)]
-use crate::string;
-#[cfg(bootstrap)]
-use crate::sync::Arc;
-#[cfg(bootstrap)]
-use crate::time;
-#[cfg(not(bootstrap))]
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::error::Error;
-/// `Error` is a trait representing the basic expectations for error values,
-/// i.e., values of type `E` in [`Result<T, E>`].
-///
-/// Errors must describe themselves through the [`Display`] and [`Debug`]
-/// traits. Error messages are typically concise lowercase sentences without
-/// trailing punctuation:
-///
-/// ```
-/// let err = "NaN".parse::<u32>().unwrap_err();
-/// assert_eq!(err.to_string(), "invalid digit found in string");
-/// ```
-///
-/// Errors may provide cause information. [`Error::source()`] is generally
-/// used when errors cross "abstraction boundaries". If one module must report
-/// an error that is caused by an error from a lower-level module, it can allow
-/// accessing that error via [`Error::source()`]. This makes it possible for the
-/// high-level module to provide its own errors while also revealing some of the
-/// implementation for debugging.
-#[stable(feature = "rust1", since = "1.0.0")]
-#[cfg_attr(not(test), rustc_diagnostic_item = "Error")]
-#[cfg(bootstrap)]
-pub trait Error: Debug + Display {
- /// The lower-level source of this error, if any.
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::fmt;
- ///
- /// #[derive(Debug)]
- /// struct SuperError {
- /// source: SuperErrorSideKick,
- /// }
- ///
- /// impl fmt::Display for SuperError {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "SuperError is here!")
- /// }
- /// }
- ///
- /// impl Error for SuperError {
- /// fn source(&self) -> Option<&(dyn Error + 'static)> {
- /// Some(&self.source)
- /// }
- /// }
- ///
- /// #[derive(Debug)]
- /// struct SuperErrorSideKick;
- ///
- /// impl fmt::Display for SuperErrorSideKick {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "SuperErrorSideKick is here!")
- /// }
- /// }
- ///
- /// impl Error for SuperErrorSideKick {}
- ///
- /// fn get_super_error() -> Result<(), SuperError> {
- /// Err(SuperError { source: SuperErrorSideKick })
- /// }
- ///
- /// fn main() {
- /// match get_super_error() {
- /// Err(e) => {
- /// println!("Error: {e}");
- /// println!("Caused by: {}", e.source().unwrap());
- /// }
- /// _ => println!("No error"),
- /// }
- /// }
- /// ```
- #[stable(feature = "error_source", since = "1.30.0")]
- fn source(&self) -> Option<&(dyn Error + 'static)> {
- None
- }
-
- /// Gets the `TypeId` of `self`.
- #[doc(hidden)]
- #[unstable(
- feature = "error_type_id",
- reason = "this is memory-unsafe to override in user code",
- issue = "60784"
- )]
- fn type_id(&self, _: private::Internal) -> TypeId
- where
- Self: 'static,
- {
- TypeId::of::<Self>()
- }
-
- /// ```
- /// if let Err(e) = "xc".parse::<u32>() {
- /// // Print `e` itself, no need for description().
- /// eprintln!("Error: {e}");
- /// }
- /// ```
- #[stable(feature = "rust1", since = "1.0.0")]
- #[deprecated(since = "1.42.0", note = "use the Display impl or to_string()")]
- fn description(&self) -> &str {
- "description() is deprecated; use Display"
- }
-
- #[stable(feature = "rust1", since = "1.0.0")]
- #[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()
- }
-
- /// Provides type based access to context intended for error reports.
- ///
- /// Used in conjunction with [`Demand::provide_value`] and [`Demand::provide_ref`] to extract
- /// references to member variables from `dyn Error` trait objects.
- ///
- /// # Example
- ///
- /// ```rust
- /// #![feature(provide_any)]
- /// #![feature(error_generic_member_access)]
- /// use core::fmt;
- /// use core::any::Demand;
- ///
- /// #[derive(Debug)]
- /// struct MyBacktrace {
- /// // ...
- /// }
- ///
- /// impl MyBacktrace {
- /// fn new() -> MyBacktrace {
- /// // ...
- /// # MyBacktrace {}
- /// }
- /// }
- ///
- /// #[derive(Debug)]
- /// struct SourceError {
- /// // ...
- /// }
- ///
- /// impl fmt::Display for SourceError {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "Example Source Error")
- /// }
- /// }
- ///
- /// impl std::error::Error for SourceError {}
- ///
- /// #[derive(Debug)]
- /// struct Error {
- /// source: SourceError,
- /// backtrace: MyBacktrace,
- /// }
- ///
- /// impl fmt::Display for Error {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "Example Error")
- /// }
- /// }
- ///
- /// impl std::error::Error for Error {
- /// fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
- /// demand
- /// .provide_ref::<MyBacktrace>(&self.backtrace)
- /// .provide_ref::<dyn std::error::Error + 'static>(&self.source);
- /// }
- /// }
- ///
- /// fn main() {
- /// let backtrace = MyBacktrace::new();
- /// let source = SourceError {};
- /// let error = Error { source, backtrace };
- /// let dyn_error = &error as &dyn std::error::Error;
- /// let backtrace_ref = dyn_error.request_ref::<MyBacktrace>().unwrap();
- ///
- /// assert!(core::ptr::eq(&error.backtrace, backtrace_ref));
- /// }
- /// ```
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- #[allow(unused_variables)]
- fn provide<'a>(&'a self, demand: &mut Demand<'a>) {}
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "error_generic_member_access", issue = "99301")]
-impl<'b> Provider for dyn Error + 'b {
- fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
- self.provide(demand)
- }
-}
-
mod private {
// This is a hack to prevent `type_id` from being overridden by `Error`
// implementations, since that can enable unsound downcasting.
pub struct Internal;
}
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
- /// Converts a type of [`Error`] into a box of dyn [`Error`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::fmt;
- /// use std::mem;
- ///
- /// #[derive(Debug)]
- /// struct AnError;
- ///
- /// impl fmt::Display for AnError {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "An error")
- /// }
- /// }
- ///
- /// impl Error for AnError {}
- ///
- /// let an_error = AnError;
- /// assert!(0 == mem::size_of_val(&an_error));
- /// let a_boxed_error = Box::<dyn Error>::from(an_error);
- /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(err: E) -> Box<dyn Error + 'a> {
- Box::new(err)
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> {
- /// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of
- /// dyn [`Error`] + [`Send`] + [`Sync`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::fmt;
- /// use std::mem;
- ///
- /// #[derive(Debug)]
- /// struct AnError;
- ///
- /// impl fmt::Display for AnError {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "An error")
- /// }
- /// }
- ///
- /// impl Error for AnError {}
- ///
- /// unsafe impl Send for AnError {}
- ///
- /// unsafe impl Sync for AnError {}
- ///
- /// let an_error = AnError;
- /// assert!(0 == mem::size_of_val(&an_error));
- /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
- /// assert!(
- /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> {
- Box::new(err)
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl From<String> for Box<dyn Error + Send + Sync> {
- /// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- ///
- /// let a_string_error = "a string error".to_string();
- /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
- /// assert!(
- /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- #[inline]
- fn from(err: String) -> Box<dyn Error + Send + Sync> {
- struct StringError(String);
-
- impl Error for StringError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- &self.0
- }
- }
-
- impl Display for StringError {
- fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- Display::fmt(&self.0, f)
- }
- }
-
- // Purposefully skip printing "StringError(..)"
- impl Debug for StringError {
- fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- Debug::fmt(&self.0, f)
- }
- }
-
- Box::new(StringError(err))
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "string_box_error", since = "1.6.0")]
-impl From<String> for Box<dyn Error> {
- /// Converts a [`String`] into a box of dyn [`Error`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- ///
- /// let a_string_error = "a string error".to_string();
- /// let a_boxed_error = Box::<dyn Error>::from(a_string_error);
- /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(str_err: String) -> Box<dyn Error> {
- let err1: Box<dyn Error + Send + Sync> = From::from(str_err);
- let err2: Box<dyn Error> = err1;
- err2
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
- /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
- ///
- /// [`str`]: prim@str
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- ///
- /// let a_str_error = "a str error";
- /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
- /// assert!(
- /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- #[inline]
- fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> {
- From::from(String::from(err))
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "string_box_error", since = "1.6.0")]
-impl From<&str> for Box<dyn Error> {
- /// Converts a [`str`] into a box of dyn [`Error`].
- ///
- /// [`str`]: prim@str
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- ///
- /// let a_str_error = "a str error";
- /// let a_boxed_error = Box::<dyn Error>::from(a_str_error);
- /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(err: &str) -> Box<dyn Error> {
- From::from(String::from(err))
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cow_box_error", since = "1.22.0")]
-impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
- /// Converts a [`Cow`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- /// use std::borrow::Cow;
- ///
- /// let a_cow_str_error = Cow::from("a str error");
- /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
- /// assert!(
- /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a> {
- From::from(String::from(err))
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cow_box_error", since = "1.22.0")]
-impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
- /// Converts a [`Cow`] into a box of dyn [`Error`].
- ///
- /// # Examples
- ///
- /// ```
- /// use std::error::Error;
- /// use std::mem;
- /// use std::borrow::Cow;
- ///
- /// let a_cow_str_error = Cow::from("a str error");
- /// let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
- /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
- /// ```
- fn from(err: Cow<'a, str>) -> Box<dyn Error> {
- From::from(String::from(err))
- }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "never_type", issue = "35121")]
-impl Error for ! {}
-
-#[cfg(bootstrap)]
-#[unstable(
- feature = "allocator_api",
- reason = "the precise API and guarantees it provides may be tweaked.",
- issue = "32838"
-)]
-impl Error for AllocError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "alloc_layout", since = "1.28.0")]
-impl Error for LayoutError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for str::ParseBoolError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "failed to parse bool"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for str::Utf8Error {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "invalid utf-8: corrupt contents"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for num::ParseIntError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for num::TryFromIntError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for array::TryFromSliceError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for num::ParseFloatError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for string::FromUtf8Error {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "invalid utf-8"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for string::FromUtf16Error {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "invalid utf-16"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "str_parse_error2", since = "1.8.0")]
-impl Error for Infallible {
- fn description(&self) -> &str {
- match *self {}
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "decode_utf16", since = "1.9.0")]
-impl Error for char::DecodeUtf16Error {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "unpaired surrogate found"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "u8_from_char", since = "1.59.0")]
-impl Error for char::TryFromCharError {}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "map_try_insert", issue = "82766")]
-impl<'a, K: Debug + Ord, V: Debug> Error
- for crate::collections::btree_map::OccupiedError<'a, K, V>
-{
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "key already exists"
- }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "map_try_insert", issue = "82766")]
-impl<'a, K: Debug, V: Debug> Error for crate::collections::hash_map::OccupiedError<'a, K, V> {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "key already exists"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "box_error", since = "1.8.0")]
-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)
- }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "thin_box", issue = "92791")]
-impl<T: ?Sized + crate::error::Error> crate::error::Error for crate::boxed::ThinBox<T> {
- fn source(&self) -> Option<&(dyn crate::error::Error + 'static)> {
- use core::ops::Deref;
- self.deref().source()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "error_by_ref", since = "1.51.0")]
-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)
- }
-
- fn provide<'b>(&'b self, demand: &mut Demand<'b>) {
- Error::provide(&**self, demand);
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "arc_error", since = "1.52.0")]
-impl<T: Error + ?Sized> Error for Arc<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)
- }
-
- fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
- Error::provide(&**self, demand);
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "fmt_error", since = "1.11.0")]
-impl Error for fmt::Error {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "an error occurred when formatting an argument"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for cell::BorrowError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "already mutably borrowed"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for cell::BorrowMutError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "already borrowed"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for char::CharTryFromError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "converted integer out of range for `char`"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "char_from_str", since = "1.20.0")]
-impl Error for char::ParseCharError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_reserve", since = "1.57.0")]
-impl Error for alloc::collections::TryReserveError {}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "duration_checked_float", issue = "83400")]
-impl Error for time::FromFloatSecsError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for alloc::ffi::NulError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "nul byte found in data"
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl From<alloc::ffi::NulError> for io::Error {
- /// Converts a [`alloc::ffi::NulError`] into a [`io::Error`].
- fn from(_: alloc::ffi::NulError) -> io::Error {
- io::const_io_error!(io::ErrorKind::InvalidInput, "data provided contains a nul byte")
- }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
-impl Error for core::ffi::FromBytesWithNulError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- self.__description()
- }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")]
-impl Error for core::ffi::FromBytesUntilNulError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
-impl Error for alloc::ffi::FromVecWithNulError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cstring_into", since = "1.7.0")]
-impl Error for alloc::ffi::IntoStringError {
- #[allow(deprecated)]
- fn description(&self) -> &str {
- "C string contained non-utf8 bytes"
- }
-
- fn source(&self) -> Option<&(dyn Error + 'static)> {
- Some(self.__source())
- }
-}
-
-#[cfg(bootstrap)]
-impl<'a> dyn Error + 'a {
- /// Request a reference of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_ref<T: ?Sized + 'static>(&'a self) -> Option<&'a T> {
- core::any::request_ref(self)
- }
-
- /// Request a value of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_value<T: 'static>(&'a self) -> Option<T> {
- core::any::request_value(self)
- }
-}
-
-// Copied from `any.rs`.
-#[cfg(bootstrap)]
-impl dyn Error + 'static {
- /// Returns `true` if the inner type is the same as `T`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn is<T: Error + 'static>(&self) -> bool {
- // Get `TypeId` of the type this function is instantiated with.
- let t = TypeId::of::<T>();
-
- // Get `TypeId` of the type in the trait object (`self`).
- let concrete = self.type_id(private::Internal);
-
- // Compare both `TypeId`s on equality.
- t == concrete
- }
-
- /// Returns some reference to the inner value if it is of type `T`, or
- /// `None` if it isn't.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
- if self.is::<T>() {
- unsafe { Some(&*(self as *const dyn Error as *const T)) }
- } else {
- None
- }
- }
-
- /// Returns some mutable reference to the inner value if it is of type `T`, or
- /// `None` if it isn't.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
- if self.is::<T>() {
- unsafe { Some(&mut *(self as *mut dyn Error as *mut T)) }
- } else {
- None
- }
- }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + 'static + Send {
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn is<T: Error + 'static>(&self) -> bool {
- <dyn Error + 'static>::is::<T>(self)
- }
-
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
- <dyn Error + 'static>::downcast_ref::<T>(self)
- }
-
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
- <dyn Error + 'static>::downcast_mut::<T>(self)
- }
-
- /// Request a reference of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> {
- <dyn Error>::request_ref(self)
- }
-
- /// Request a value of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_value<T: 'static>(&self) -> Option<T> {
- <dyn Error>::request_value(self)
- }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + 'static + Send + Sync {
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn is<T: Error + 'static>(&self) -> bool {
- <dyn Error + 'static>::is::<T>(self)
- }
-
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
- <dyn Error + 'static>::downcast_ref::<T>(self)
- }
-
- /// Forwards to the method defined on the type `dyn Error`.
- #[stable(feature = "error_downcast", since = "1.3.0")]
- #[inline]
- pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
- <dyn Error + 'static>::downcast_mut::<T>(self)
- }
-
- /// Request a reference of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> {
- <dyn Error>::request_ref(self)
- }
-
- /// Request a value of type `T` as context about this error.
- #[unstable(feature = "error_generic_member_access", issue = "99301")]
- pub fn request_value<T: 'static>(&self) -> Option<T> {
- <dyn Error>::request_value(self)
- }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error {
- #[inline]
- #[stable(feature = "error_downcast", since = "1.3.0")]
- /// Attempts to downcast the box to a concrete type.
- pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> {
- if self.is::<T>() {
- unsafe {
- let raw: *mut dyn Error = Box::into_raw(self);
- Ok(Box::from_raw(raw as *mut T))
- }
- } else {
- Err(self)
- }
- }
-
- /// Returns an iterator starting with the current error and continuing with
- /// recursively calling [`Error::source`].
- ///
- /// If you want to omit the current error and only use its sources,
- /// use `skip(1)`.
- ///
- /// # Examples
- ///
- /// ```
- /// #![feature(error_iter)]
- /// use std::error::Error;
- /// use std::fmt;
- ///
- /// #[derive(Debug)]
- /// struct A;
- ///
- /// #[derive(Debug)]
- /// struct B(Option<Box<dyn Error + 'static>>);
- ///
- /// impl fmt::Display for A {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "A")
- /// }
- /// }
- ///
- /// impl fmt::Display for B {
- /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- /// write!(f, "B")
- /// }
- /// }
- ///
- /// impl Error for A {}
- ///
- /// impl Error for B {
- /// fn source(&self) -> Option<&(dyn Error + 'static)> {
- /// self.0.as_ref().map(|e| e.as_ref())
- /// }
- /// }
- ///
- /// let b = B(Some(Box::new(A)));
- ///
- /// // let err : Box<Error> = b.into(); // or
- /// let err = &b as &(dyn Error);
- ///
- /// let mut iter = err.sources();
- ///
- /// assert_eq!("B".to_string(), iter.next().unwrap().to_string());
- /// assert_eq!("A".to_string(), iter.next().unwrap().to_string());
- /// assert!(iter.next().is_none());
- /// assert!(iter.next().is_none());
- /// ```
- #[unstable(feature = "error_iter", issue = "58520")]
- #[inline]
- pub fn sources(&self) -> Sources<'_> {
- // You may think this method would be better in the Error trait, and you'd be right.
- // Unfortunately that doesn't work, not because of the object safety rules but because we
- // save a reference to self in Sources below as a trait object. If this method was
- // declared in Error, then self would have the type &T where T is some concrete type which
- // implements Error. We would need to coerce self to have type &dyn Error, but that requires
- // that Self has a known size (i.e., Self: Sized). We can't put that bound on Error
- // since that would forbid Error trait objects, and we can't put that bound on the method
- // because that means the method can't be called on trait objects (we'd also need the
- // 'static bound, but that isn't allowed because methods with bounds on Self other than
- // Sized are not object-safe). Requiring an Unsize bound is not backwards compatible.
-
- Sources { current: Some(self) }
- }
-}
-
-/// An iterator over an [`Error`] and its sources.
-///
-/// If you want to omit the initial error and only process
-/// its sources, use `skip(1)`.
-#[unstable(feature = "error_iter", issue = "58520")]
-#[derive(Clone, Debug)]
-#[cfg(bootstrap)]
-pub struct Sources<'a> {
- current: Option<&'a (dyn Error + 'static)>,
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "error_iter", issue = "58520")]
-impl<'a> Iterator for Sources<'a> {
- type Item = &'a (dyn Error + 'static);
-
- fn next(&mut self) -> Option<Self::Item> {
- let current = self.current;
- self.current = self.current.and_then(Error::source);
- current
- }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + Send {
- #[inline]
- #[stable(feature = "error_downcast", since = "1.3.0")]
- /// Attempts to downcast the box to a concrete type.
- pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> {
- let err: Box<dyn Error> = self;
- <dyn Error>::downcast(err).map_err(|s| unsafe {
- // Reapply the `Send` marker.
- transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s)
- })
- }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + Send + Sync {
- #[inline]
- #[stable(feature = "error_downcast", since = "1.3.0")]
- /// Attempts to downcast the box to a concrete type.
- pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
- let err: Box<dyn Error> = self;
- <dyn Error>::downcast(err).map_err(|s| unsafe {
- // Reapply the `Send + Sync` marker.
- transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s)
- })
- }
-}
-
/// An error reporter that prints an error and its sources.
///
/// Report also exposes configuration options for formatting the error sources, either entirely on a
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