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yaahcyaahc
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more docs improvements
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‎library/std/src/error.rs

+207-35
Original file line numberDiff line numberDiff line change
@@ -869,8 +869,10 @@ impl dyn Error + Send + Sync {
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/// Error: SuperError is here!: SuperErrorSideKick is here!
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/// ```
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///
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/// ## Output consistency
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///
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/// Report prints the same output via `Display` and `Debug`, so it works well with
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/// [`unwrap`]/[`expect`]:
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/// [`Result::unwrap`]/[`Result::expect`] which print their `Err` variant via `Debug`:
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///
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/// ```should_panic
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/// #![feature(error_reporter)]
@@ -912,6 +914,104 @@ impl dyn Error + Send + Sync {
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/// thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: SuperError is here!: SuperErrorSideKick is here!', src/error.rs:34:40
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/// note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
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/// ```
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// /// TODO: Report doesn't yet support return from `main` gracefully, fix in followup (yaahc)
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// /// ## Return from `main`
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// ///
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// /// `Report` also implements `From` for all types that implement [`Error`], this when combined with
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// /// the `Debug` output means `Report` is an ideal starting place for formatting errors returned
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// /// from `main`.
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// ///
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// /// ```
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// /// #![feature(error_reporter)]
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// /// use std::error::Report;
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// /// # use std::error::Error;
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// /// # use std::fmt;
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// /// # #[derive(Debug)]
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// /// # struct SuperError {
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// /// # source: SuperErrorSideKick,
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// /// # }
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// /// # impl fmt::Display for SuperError {
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// /// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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// /// # write!(f, "SuperError is here!")
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// /// # }
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// /// # }
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// /// # impl Error for SuperError {
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// /// # fn source(&self) -> Option<&(dyn Error + 'static)> {
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// /// # Some(&self.source)
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// /// # }
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// /// # }
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// /// # #[derive(Debug)]
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// /// # struct SuperErrorSideKick;
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// /// # impl fmt::Display for SuperErrorSideKick {
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// /// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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// /// # write!(f, "SuperErrorSideKick is here!")
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// /// # }
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// /// # }
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// /// # impl Error for SuperErrorSideKick {}
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// /// # fn get_super_error() -> Result<(), SuperError> {
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// /// # Err(SuperError { source: SuperErrorSideKick })
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// /// # }
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// ///
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// /// fn main() -> Result<(), Report> {
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// /// get_super_error()?;
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// /// }
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// /// ```
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// ///
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// /// This example produces the following output:
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// ///
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// /// ```console
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// /// thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: SuperError is here!: SuperErrorSideKick is here!', src/error.rs:34:40
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// /// note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
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// /// ```
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// ///
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// /// **Note**: `Report`s constructed via `?` and `From` will be configured to use the single line
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// /// output format, if you want to make sure your `Report`s are pretty printed and include backtrace
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// /// you will need to manually convert and enable those flags.
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// ///
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// /// ```
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// /// #![feature(error_reporter)]
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// /// use std::error::Report;
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// /// # use std::error::Error;
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// /// # use std::fmt;
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// /// # #[derive(Debug)]
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// /// # struct SuperError {
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// /// # source: SuperErrorSideKick,
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// /// # }
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// /// # impl fmt::Display for SuperError {
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// /// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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// /// # write!(f, "SuperError is here!")
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// /// # }
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// /// # }
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// /// # impl Error for SuperError {
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// /// # fn source(&self) -> Option<&(dyn Error + 'static)> {
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// /// # Some(&self.source)
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// /// # }
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// /// # }
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// /// # #[derive(Debug)]
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// /// # struct SuperErrorSideKick;
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// /// # impl fmt::Display for SuperErrorSideKick {
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// /// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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// /// # write!(f, "SuperErrorSideKick is here!")
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// /// # }
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// /// # }
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// /// # impl Error for SuperErrorSideKick {}
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// /// # fn get_super_error() -> Result<(), SuperError> {
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// /// # Err(SuperError { source: SuperErrorSideKick })
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// /// # }
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// ///
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// /// fn main() -> Result<(), Report> {
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// /// get_super_error()
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// /// .map_err(Report::new)
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// /// .map_err(|r| r.pretty(true).show_backtrace(true))?;
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// /// }
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// /// ```
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// ///
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// /// This example produces the following output:
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// ///
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// /// ```console
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// /// thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: SuperError is here!: SuperErrorSideKick is here!', src/error.rs:34:40
1013+
// /// note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
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// /// ```
9151015
#[unstable(feature = "error_reporter", issue = "90172")]
9161016
pub struct Report<E> {
9171017
/// The error being reported.
@@ -977,6 +1077,68 @@ where
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/// Caused by:
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/// SuperErrorSideKick is here!
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/// ```
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///
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/// When there are multiple source errors the causes will be numbered in order of iteration
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/// starting from the outermost error.
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///
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/// ```rust
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/// #![feature(error_reporter)]
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/// use std::error::Report;
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/// # use std::error::Error;
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/// # use std::fmt;
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/// # #[derive(Debug)]
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/// # struct SuperError {
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/// # source: SuperErrorSideKick,
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/// # }
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/// # impl fmt::Display for SuperError {
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/// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// # write!(f, "SuperError is here!")
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/// # }
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/// # }
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/// # impl Error for SuperError {
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/// # fn source(&self) -> Option<&(dyn Error + 'static)> {
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/// # Some(&self.source)
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/// # }
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/// # }
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/// # #[derive(Debug)]
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/// # struct SuperErrorSideKick {
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/// # source: SuperErrorSideKickSideKick,
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/// # }
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/// # impl fmt::Display for SuperErrorSideKick {
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/// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// # write!(f, "SuperErrorSideKick is here!")
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/// # }
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/// # }
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/// # impl Error for SuperErrorSideKick {
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/// # fn source(&self) -> Option<&(dyn Error + 'static)> {
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/// # Some(&self.source)
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/// # }
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/// # }
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/// # #[derive(Debug)]
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/// # struct SuperErrorSideKickSideKick;
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/// # impl fmt::Display for SuperErrorSideKickSideKick {
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/// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// # write!(f, "SuperErrorSideKickSideKick is here!")
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/// # }
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/// # }
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/// # impl Error for SuperErrorSideKickSideKick { }
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///
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/// let source = SuperErrorSideKickSideKick;
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/// let source = SuperErrorSideKick { source };
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/// let error = SuperError { source };
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/// let report = Report::new(error).pretty(true);
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/// eprintln!("Error: {:?}", report);
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/// ```
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///
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/// This example produces the following output:
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///
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/// ```console
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/// Error: SuperError is here!
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///
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/// Caused by:
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/// 0: SuperErrorSideKick is here!
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/// 1: SuperErrorSideKickSideKick is here!
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/// ```
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#[unstable(feature = "error_reporter", issue = "90172")]
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pub fn pretty(mut self, pretty: bool) -> Self {
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self.pretty = pretty;
@@ -987,38 +1149,40 @@ where
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///
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/// # Examples
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///
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/// **Note**: Report will search for the first `Backtrace` it can find starting from the
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/// outermost error. In this example it will display the backtrace from the second error in the
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/// chain, `SuperErrorSideKick`.
1155+
///
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/// ```rust
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/// #![feature(error_reporter)]
9921158
/// #![feature(backtrace)]
993-
/// use std::error::{Error, Report};
1159+
/// # use std::error::Error;
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/// # use std::fmt;
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/// use std::error::Report;
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/// use std::backtrace::Backtrace;
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/// use std::fmt;
996-
///
997-
/// #[derive(Debug)]
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/// struct SuperError {
999-
/// source: SuperErrorSideKick,
1000-
/// }
1001-
///
1002-
/// impl fmt::Display for SuperError {
1003-
/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// write!(f, "SuperError is here!")
1005-
/// }
1006-
/// }
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///
1008-
/// impl Error for SuperError {
1009-
/// fn source(&self) -> Option<&(dyn Error + 'static)> {
1010-
/// Some(&self.source)
1011-
/// }
1012-
/// }
10131163
///
1164+
/// # #[derive(Debug)]
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/// # struct SuperError {
1166+
/// # source: SuperErrorSideKick,
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/// # }
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/// # impl fmt::Display for SuperError {
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/// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// # write!(f, "SuperError is here!")
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/// # }
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/// # }
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/// # impl Error for SuperError {
1174+
/// # fn source(&self) -> Option<&(dyn Error + 'static)> {
1175+
/// # Some(&self.source)
1176+
/// # }
1177+
/// # }
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/// #[derive(Debug)]
10151179
/// struct SuperErrorSideKick {
10161180
/// backtrace: Backtrace,
10171181
/// }
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///
1019-
/// impl fmt::Display for SuperErrorSideKick {
1020-
/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1021-
/// write!(f, "SuperErrorSideKick is here!")
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/// impl SuperErrorSideKick {
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/// fn new() -> SuperErrorSideKick {
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/// SuperErrorSideKick { backtrace: Backtrace::force_capture() }
10221186
/// }
10231187
/// }
10241188
///
@@ -1028,7 +1192,14 @@ where
10281192
/// }
10291193
/// }
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///
1031-
/// let source = SuperErrorSideKick { backtrace: Backtrace::force_capture() };
1195+
/// // The rest of the example is unchanged ...
1196+
/// # impl fmt::Display for SuperErrorSideKick {
1197+
/// # fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1198+
/// # write!(f, "SuperErrorSideKick is here!")
1199+
/// # }
1200+
/// # }
1201+
///
1202+
/// let source = SuperErrorSideKick::new();
10321203
/// let error = SuperError { source };
10331204
/// let report = Report::new(error).pretty(true).show_backtrace(true);
10341205
/// eprintln!("Error: {:?}", report);
@@ -1043,17 +1214,18 @@ where
10431214
/// SuperErrorSideKick is here!
10441215
///
10451216
/// Stack backtrace:
1046-
/// 0: rust_out::main::_doctest_main_src_error_rs_943_0
1047-
/// 1: rust_out::main
1048-
/// 2: core::ops::function::FnOnce::call_once
1049-
/// 3: std::sys_common::backtrace::__rust_begin_short_backtrace
1050-
/// 4: std::rt::lang_start::{{closure}}
1051-
/// 5: std::panicking::try
1052-
/// 6: std::rt::lang_start_internal
1053-
/// 7: std::rt::lang_start
1054-
/// 8: main
1055-
/// 9: __libc_start_main
1056-
/// 10: _start
1217+
/// 0: rust_out::main::_doctest_main_src_error_rs_1158_0::SuperErrorSideKick::new
1218+
/// 1: rust_out::main::_doctest_main_src_error_rs_1158_0
1219+
/// 2: rust_out::main
1220+
/// 3: core::ops::function::FnOnce::call_once
1221+
/// 4: std::sys_common::backtrace::__rust_begin_short_backtrace
1222+
/// 5: std::rt::lang_start::{{closure}}
1223+
/// 6: std::panicking::try
1224+
/// 7: std::rt::lang_start_internal
1225+
/// 8: std::rt::lang_start
1226+
/// 9: main
1227+
/// 10: __libc_start_main
1228+
/// 11: _start
10571229
/// ```
10581230
#[unstable(feature = "error_reporter", issue = "90172")]
10591231
pub fn show_backtrace(mut self, show_backtrace: bool) -> Self {

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