pin-project 0.4.11 breaks hyper

[Will Glozer]

Hello, hyper uses #[project] on an expression https://github.com/hyperium/hyper/blob/v0.13.5/src/server/conn.rs#L926 and https://github.com/hyperium/hyper/blob/v0.13.5/src/server/shutdown.rs#L65 which now causes a compilation error with pin-project 0.4.11.

Here is one of your test cases adapted to demonstrate the issue, this code works fine with 0.4.10 but not 0.4.11:

#[project]
fn foo() {
    #[pin_project]
    enum Enum<A> {
        Variant(#[pin] A),
    }

    let mut x = Enum::Variant(1);
    let mut x = Pin::new(&mut x).project();

    let asdf = {
        #[project]
        match x {
            Enum::Variant(x) => {}
        }
    };

    Some(asdf);
}

Error:

error[E0658]: attributes on expressions are experimental
  --> src/main.rs:16:9
   |
16 |         #[project]
   |         ^^^^^^^^^^
   |
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable

[Taiki Endo]

Thanks for the reporting! I yanked 0.4.11. I'll look into this.

[baoyachi]

provisional measures soultion:

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

[Taiki Endo]

I released 0.4.12 based on 0.4.10. (It should be fixed by updating Cargo.lock: cargo update)

[Taiki Endo]

Ok, this is due to #197's visiter skips visiting initializer expression on local (will be fixed in #207).

EDIT: see #206 (comment)

[Taiki Endo]

Oops, it actually seems to skip all expressions visits nested by expressions, not just local.
Either way, #207 should fix it.

[Will Glozer]

Thank you for the quick fix!