# Core Error
Traits for working with `Error` in `std`-less environments.
## Warning
This is a pre-release meant to allow experimentation and integration into the
various error handling crates. Please do not use it yet! 1.0.0 is right around
the corner.
## Rationale
With the recent proliferation of error-handling crates, it has become clear that
the situation around the lack of a `core::error::Error` is really suboptimal. In
`snafu`, `no_std` support is being introduced through a whole new Error trait
just for `no_std` - which could lead to similar problems that `failure` had by
becoming incompatible with the ecosystem.
Ideally, the `Error` trait would show up in core, but due to coherence concerns
and std-dependent features being added to `std::error::Error`, a resolution is
unlikely to happen soon. As such, I propose making a new crate, `core-error` -
exposing our own version of the `Error` trait. The goal of this crate is
twofolds:
- Provide a common trait for various error handling crates (Failure, Snafu,
Fehler, Anyhow, error_chain, and any others?)
- Allow no_std libraries that don't want to depend on a specific error handling
crate to still expose errors that can interoperate with those libraries.
This crate is still in the early stages. Once it reaches 1.0.0, it will be ready
for integration in the various error crates. Furthermore, once it reaches 1.0.0,
it will follow the same stability guarantees Rust does.
# Usage
This crate simply provides an Error trait, which is identical to the one in std
except for not providing deprecated methods. It also contains two features:
- `std`: simply reexport `std::error::Error`
- `alloc`: implement Error on alloc Errors (incl. Box)
Libraries using this crate should forward their equivalent features to this
library.
# Minimum Rust Version
This crate works all the way down to 1.0.0. It auto-detects the Rust version in
order to know which error structs to implement the trait on.
With `no-default-features`, the crate only compiles from 1.13.0 onwards (See #11
for the reason why this release is the minimum suported version).