On Wed, Dec 21, 2016, at 12:30 PM, Jason Orendorff wrote: > The implicit conversion solves a real problem. Imagine these two > operations > have two different error types: > > MOZ_TRY(JS_DoFirstThing()); // JS::Error& > MOZ_TRY(mozilla::pkix::DoSecondThing()); // pkix::Error > > We don't want our error-handling scheme getting in the way of using them > together. So we need a way of unifying the two error types: a shared base > class, perhaps, or a variant. > > Experience with Rust says that MOZ_TRY definitely needs to address this > problem somehow. C++ implicit conversion is just one way to go; we can > discuss alternatives in the bug.
The `try` macro in Rust will auto-convert error types that implement `Into<E>`, AIUI, but that's not automatic for all error types. I haven't tried it, but I have seen multiple recommendations for the `error_chain` crate to make this smoother: https://docs.rs/error-chain/0.7.1/error_chain/ It's basically just boilerplate to implement conversions from other error types. I wouldn't be surprised if something like that percolates into the Rust standard library at some point. -Ted _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
