Error-chain is no longer maintained

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7

I used to use error-chain and failure, but I tend to just write my errors directly now, so I have control over how they work. A simple error would be something like

#[derive(Debug)]
pub enum MyError {
    CannotOpenFile(io::Error),
    CannotReadData(io::Error),
    // ...
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            MyError::CannotOpenFile(e) => write!(f, "error while opening file: {}", e),
            // ....
        }
    }
}

impl Error for MyError {
    fn source(&self) -> &dyn Error {
        match self {
            MyError::CannotOpenFile(e) => e,
            // ...
        }
    }
}

You don't have to impl the source method if you think the fmt msg is enough, in which case you'd have

impl Error for MyError {}

which is a bit shorter :slight_smile: