Struct BoxedError2 

pub struct BoxedError2 { /* private fields */ }

Type-erased error with automatic backtrace tracking.

BoxedError2 provides anyhow-like ergonomics with type erasure, allowing you to work with errors without specifying concrete types.

Features

• Type Erasure: Store any error implementing Error2 or std::error::Error
• Downcasting: Retrieve the original error type
• Backtrace: Access complete error chain and locations

Conversion Control

Use Via* types to control how errors are wrapped:

use error2::prelude::*;

fn example() -> Result<(), BoxedError2> {
    // Wrap std::error::Error
    std::fs::read_to_string("file.txt").context(ViaStd)?;

    Ok(())
}

See ViaRoot, ViaStd, and ViaErr2 for details.

Downcasting

Retrieve the original error type:

use std::io;

use error2::{kind::ErrorKind, prelude::*};

let err = std::io::Error::from(std::io::ErrorKind::NotFound);
let boxed = BoxedError2::from_std(err);

match boxed.downcast_ref::<io::Error>() {
    Some(ErrorKind::Std { source, .. }) => {
        println!("IO error: {}", source);
    }
    _ => {}
}

Implementations

impl BoxedError2

pub fn is_root(&self) -> bool

Checks if this is a root error (not wrapping another error).

pub fn is<T: Error + 'static>(&self) -> bool

Checks if the boxed error contains an error of type T.

pub fn downcast_ref<T: Error + 'static>( &self, ) -> Option<ErrorKind<&T, &Backtrace>>

Attempts to downcast to a reference of type T.

Returns Some(ErrorKind) if the error is of type T.

pub fn downcast_mut<T: Error + 'static>( &mut self, ) -> Option<ErrorKind<&mut T, &mut Backtrace>>

Attempts to downcast to a mutable reference of type T.

pub fn downcast<T: Error + 'static>( self, ) -> Result<ErrorKind<T, Backtrace>, Self>

Attempts to downcast to an owned value of type T.

Returns Ok(ErrorKind) if successful, or Err(self) on failure.

impl BoxedError2

pub fn from_root<R>(root: R) -> BoxedError2

where R: Display + Debug + Send + Sync + 'static,

Creates a BoxedError2 from a root error message.

Use for errors that don’t wrap other errors.

pub fn from_root_with_location<R>(root: R, location: Location) -> BoxedError2

where R: Display + Debug + Send + Sync + 'static,

Creates a root error with explicit location.

pub fn from_std<T>(source: T) -> BoxedError2

where T: Error + Send + Sync + 'static,

Creates a BoxedError2 from a std::error::Error.

Wraps standard library or third-party errors.

pub fn from_std_with_location<T>(source: T, location: Location) -> BoxedError2

where T: Error + Send + Sync + 'static,

Creates from std::error::Error with explicit location.

pub fn from_err2<T>(source: T) -> BoxedError2

where T: Error2 + Send + Sync + 'static,

Creates a BoxedError2 from an Error2 type.

Preserves the original error’s backtrace.

pub fn from_err2_with_location<T>(source: T, location: Location) -> BoxedError2

where T: Error2 + Send + Sync + 'static,

Creates from Error2 with explicit location.

Trait Implementations

impl Debug for BoxedError2

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for BoxedError2

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for BoxedError2

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl Error2 for BoxedError2

fn backtrace(&self) -> &Backtrace

Returns a reference to the error’s backtrace.

fn backtrace_mut(&mut self) -> &mut Backtrace

Returns a mutable reference to the error’s backtrace.