Compile errors at hyper-0.13.5/src/server/conn.rs:926:21 and hyper-0.13.5/src/server/shutdown.rs:65:17

[jeremyandrews]

Tests on my project, Goose, just started failing. Locally I ran a cargo update and now can duplicate. Hyper was not updated, and yet it's where the failures are happening. Please see below:

$ cargo update
    Updating crates.io index
    Updating bit-set v0.5.1 -> v0.5.2
    Updating bit-vec v0.5.1 -> v0.6.2
    Updating h2 v0.2.4 -> v0.2.5
    Updating pin-project v0.4.10 -> v0.4.11
    Updating pin-project-internal v0.4.10 -> v0.4.11
    Updating pin-project-lite v0.1.4 -> v0.1.5
    Updating syn v1.0.18 -> v1.0.19
    Updating tokio-tls v0.3.0 -> v0.3.1
    Updating vec_map v0.8.1 -> v0.8.2
$ cargo build
  Downloaded tokio-tls v0.3.1
  Downloaded syn v1.0.19
  Downloaded vec_map v0.8.2
  Downloaded pin-project v0.4.11
  Downloaded pin-project-lite v0.1.5
  Downloaded h2 v0.2.5
  Downloaded pin-project-internal v0.4.11
   Compiling syn v1.0.19
   Compiling pin-project-lite v0.1.5
   Compiling vec_map v0.8.2
   Compiling tokio v0.2.20
   Compiling clap v2.33.0
   Compiling tokio-util v0.3.1
   Compiling tokio-tls v0.3.1
   Compiling h2 v0.2.5
   Compiling syn-mid v0.5.0
   Compiling serde_derive v1.0.106
   Compiling pin-project-internal v0.4.11
   Compiling proc-macro-error-attr v1.0.2
   Compiling proc-macro-error v1.0.2
   Compiling structopt-derive v0.4.7
   Compiling pin-project v0.4.11
   Compiling hyper v0.13.5
error[E0658]: attributes on expressions are experimental
   --> /home/jandrews/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.13.5/src/server/conn.rs:926:21
    |
926 |                     #[project]
    |                     ^^^^^^^^^^
    |
    = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information

error[E0658]: custom attributes cannot be applied to expressions
   --> /home/jandrews/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.13.5/src/server/conn.rs:926:21
    |
926 |                     #[project]
    |                     ^^^^^^^^^^
    |
    = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information

error[E0658]: attributes on expressions are experimental
  --> /home/jandrews/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.13.5/src/server/shutdown.rs:65:17
   |
65 |                 #[project]
   |                 ^^^^^^^^^^
   |
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information

error[E0658]: custom attributes cannot be applied to expressions
  --> /home/jandrews/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.13.5/src/server/shutdown.rs:65:17
   |
65 |                 #[project]
   |                 ^^^^^^^^^^
   |
   = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information

   Compiling structopt v0.3.14
error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0658`.
error: could not compile `hyper`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

[seanmonstar]

Is this a nightly version of rustc?

[jeremyandrews]

No, it's current stable:

$ rustc -V
rustc 1.43.0 (4fb7144ed 2020-04-20)

Here's the test-setup on Github as well:
https://github.com/jeremyandrews/goose/blob/master/.github/workflows/CI.yml

[ghsyeung]

Maybe due to pin-project v0.4.11 changes?

https://github.com/taiki-e/pin-project/releases/tag/v0.4.11

[seanmonstar]

@taiki-e do you know if this is a regression, or something else?

[baoyachi]

provisional measures soultion:

...
[dependencies]
pin-project = "=0.4.10"
...

[taiki-e]

@seanmonstar This is a regression of pin-project (sorry!).

I yanked 0.4.11 (that has this regression) and released 0.4.12 based on 0.4.10. (It should be fixed by updating Cargo.lock: cargo update)

[jeremyandrews]

Wow, thanks for the quick triage and fix! Confirmed the issue is resolved now, thanks!

$ cargo update
    Updating crates.io index
    Updating pin-project v0.4.11 -> v0.4.12
    Updating pin-project-internal v0.4.11 -> v0.4.12
$ cargo build
  Downloaded pin-project v0.4.12
  Downloaded pin-project-internal v0.4.12
   Compiling pin-project-internal v0.4.12
   Compiling serde_urlencoded v0.6.1
   Compiling cookie_store v0.10.0
   Compiling pin-project v0.4.12
   Compiling hyper v0.13.5
   Compiling hyper-tls v0.4.1
   Compiling reqwest v0.10.4
   Compiling goose v0.5.8
    Finished dev [unoptimized + debuginfo] target(s) in 12.59s

[seanmonstar]

Thanks @taiki-e!