Macro symbolic_common::derive_failure

macro_rules! derive_failure {
    ($error:ident, $kind:ident $(, $meta:meta)* $(,)?) => { ... };
}

Defines an error type with a failure context and a kind.

The kind enum needs to be defined explicitly, and has to implement Fail already. This macro then defines an error type that wraps the kind in a failure::Context which makes it carry a backtrace and allows nesting errors, and also defines the following methods on the error type:

• kind(): Returns a reference to the error kind.
• cause(): Returns the causing error, if any.
• backtrace(): Returns the backtrace of this error (or the cause), if RUST_BACKTRACE was set.

In addition to this, the following conversions are defined for the error type:

• From<ErrorKind>
• From<Context<ErrorKind>>

Example

use failure::Fail;
#[derive(Debug, Fail)]
enum MyErrorKind {
    #[fail(display = "some")] Something,
    #[fail(display = "else")] Else,
}

derive_failure!(MyError, MyErrorKind);

fn something() -> Result<(), MyError> {
    Err(MyErrorKind::Something.into())
}