Common prefix

[jbirnick]

Let's say I want to have a common prefix to all my errors, like:

#[derive(Error)]
enum MatrixParseError {
    #[error("Couldn't parse matrix: foo")]
    Foo
    #[error("Couldn't parse matrix: bar")]
    Bar
}

It would be cool to have the ability to specify such a prefix. (E.g. as [error("Couldn't parse matrix: {}")] on the enum.)

Do you think you could add that? Or do you recommend another idiomatic way of achieving this behavior?

[afetisov]

You can extract the common part into a wrapping struct:

#[derive(Debug, Error)]
#[error("Couldn't parse matrix: {}")]
struct MatrixParseError(#[from] MatrixParseErrorKind);

#[derive(Debug, Error)]
enum MatrixParseErrorKind {
    #[error("foo")]
    Foo
    #[error("bar")]
    Bar
}

[jbirnick]

Right, thank you!

It would still be great to be able to do this without an extra wrapping struct.