1.0.2

• Add a #[from] attribute to request an implementation of std::convert::From from your error's source error types, making it easy to build your error via the ? operator.

  use thiserror::Error;
  
  #[derive(Error, Debug)]
  pub enum Error {
      Io(#[from] io::Error),
      Json(#[from] serde_json::Error),
      Regex(#[from] regex::Error),
      Other(#[from] anyhow::Error),
  }

  We only permit From to be derived from the error's source field, not any arbitrary other field. Notice that this allows #[from] to imply #[source] so you don't need to also specify #[source] explicitly.

  The variant must not contain any other fields beyond the source error and possibly a backtrace. A backtrace is captured from within the From impl if there is a field for it.

  #[derive(Error, Debug)]
  pub enum MyError {
      Io {
          #[from]
          source: io::Error,
          backtrace: Backtrace,
      },
  }

• Named fields with the name source are assumed to be the error source and so no longer require an explicit #[source] attribute.

• Enum variants now inherit the #[error(...)] attribute from atop the enum if there is one.

  use thiserror::Error;
  
  #[derive(Error, Debug)]
  #[error("{0}")] // applies to every variant without its own attr
  pub enum Error {
      Io(io::Error),
      Json(serde_json::Error),
      Regex(regex::Error),
      #[error("unknown error")]
      Unknown,
  }