Hello Edward, I'm not sure how to help with this variance bug, but I want to warn you (and it seems everyone else :)) that at least 2 other people have said they are doing a Json refactor:
https://github.com/mozilla/rust/pull/12740 https://github.com/mozilla/rust/pull/12936 If all your touching are these constructors, then it's probably not much of an issue, but if you are doing more there's a chance you could run into each other. -Erick On Sat, Mar 22, 2014 at 7:24 AM, Edward Wang <edward.yu.w...@gmail.com>wrote: > Hi, > > I'm in the process of fixing a `ty_trait` variance inference bug, which > will void the following code in json.rs: > > pub struct Encoder<'a> { > priv wr: &'a mut io::Writer, > priv error: io::IoResult<()>, > } > impl<'a> Encoder<'a> { > pub fn new<'a>(wr: &'a mut io::Writer) -> Encoder<'a> { > Encoder { wr: wr, error: Ok(()) } > } > > pub fn buffer_encode<T:Encodable<Encoder<'a>>>(to_encode_object: &T) > -> ~[u8] { > let mut m = MemWriter::new(); > { > let mut encoder = Encoder::new(&mut m as &mut io::Writer); > to_encode_object.encode(&mut encoder); > } > m.unwrap() > } > } > > If taking a close look, m here is merely a local variable but Encoder<'a> > requires a lifetime at least 'a. A naive fix would be: > > let mut encoder = Encoder::new(cast::transmute_mut_region(&mut m)); > > But of course, it is very uncivilized :) Any suggestion on how to refactor > this piece of code so it won't violate the lifetime requirement? > > Regards, > Edward > > _______________________________________________ > Rust-dev mailing list > Rust-dev@mozilla.org > https://mail.mozilla.org/listinfo/rust-dev > >
_______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
