Rocket Responder not working with v0.2.0?

[trombonehero]

I'm using Maud v0.16.1 and attempting to update Rocket from v0.1.6 to v0.2.0. The following reduced test case works fine with Rocket v0.1.6:

use rocket::response;
use rocket::response::{Responder, Response};

pub enum Foo {}

impl<'r> Responder<'r> for Foo {
    fn respond(self) -> response::Result<'r> {
        (html! {}).respond()
    }
}

With Rocket v0.2.0, however, I see:

error: no method named `respond` found for type `maud::PreEscaped<std::string::String>` in the current scope
 --> src/html/abc.rs:8:20
  |
8 |         (html! {}).respond()
  |                    ^^^^^^^
  |
  = help: items from traits can only be used if the trait is in scope; the following trait is implemented but not in scope, perhaps add a `use` for it:
  = help: candidate #1: `use rocket::response::responder::Responder;`

error: aborting due to previous error

The rocket::response::responder module is private, however, so I can't use it as suggested. I do see a respond() method at Maud's lib.rs:212 and I have features = ["rocket"] in my Cargo.toml file. Any idea why Maud's impl Responder for PreEscaped isn't being detected?

[lambda-fairy]

Can you show me the contents of your Cargo.lock? That looks like a diamond dependency issue -- if your app uses 0.2.0 but Maud is still pulling in 0.1.6, then that would explain the error.

[trombonehero]

Ah, yes, that was it: there was a 0.1.6 in Cargo.lock. Deleting the lock file and rebuilding did the trick. Sorry for the noise.

[lambda-fairy]

FYI, rust-lang/rust#22750 and rust-lang/cargo#2064 address different parts of this issue. I don't see much movement with either of them, though.

[TheNeikos]

@trombonehero Deleting your Cargo.lock shouldn't be necessary, cargo update should have been enough in that case I believe (also with --precise)