Get rid of BoxError

[MOZGIII]

Why use BoxError in the HttpsConnector if an enum would work and won't be too complicated?

In my current code, I can't just use ? or .into on the error cause it's not Sized, and, although I can work around it pretty easily, I see no reason why we shouldn't use enum.

[seanmonstar]

The reason for its use here is I didn't want to "wrap" the inner connectors errors, but instead just passing them on.

[MOZGIII]

Well, yeah, I figured. Is there a reason why you don't want to wrap the errors?
I can send you a PR with the code with the wrapping if you'd like.

[seanmonstar]

How come it can't be converted using ? or into?

[MOZGIII]

[MOZGIII]

I'm using failure::Error crate. The workaround is to .map_err(Error::from_boxed_compat) , but it's not pretty.

[MOZGIII]

Submitted a PR.
I don't see a reason why one would want to not wrap errors in this case, so if you have one I'm really curious.

[seanmonstar]

Mostly I didn't want to wrap if there was no additional context to add, since you'd need to look down the source chain one more time for err.downcast to match the wrapped error.

[MOZGIII]

A mechanism like rust-lang/rust#58289 resolves that issue almost entirely, and to avoid doing a match over the subtypes one could just to err.source().downcast() - that is not much more verbose but does just pretty much the same as downcast on currently present BoxError (one couldn't check for ForceHttpsButUriNotHttps that way too anyway).