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New higher-ranked lifetime error #105501

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khuey opened this issue Dec 9, 2022 · 1 comment · Fixed by #105915
Closed

New higher-ranked lifetime error #105501

khuey opened this issue Dec 9, 2022 · 1 comment · Fixed by #105915
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C-bug Category: This is a bug. P-critical Critical priority regression-from-stable-to-nightly Performance or correctness regression from stable to nightly.

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@khuey
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khuey commented Dec 9, 2022

error: higher-ranked lifetime error
   --> lobby-server/src/auth/github.rs:340:9
    |
340 | /         Box::pin(async move {
341 | |             let gh = this
342 | |                 .http
343 | |                 .request(req)
...   |
468 | |             }
469 | |         })
    | |__________^
    |
    = note: could not prove `std::pin::Pin<Box<[async block@lobby-server/src/auth/github.rs:340:18: 469:10]>>: CoerceUnsized<std::pin::Pin<Box<(dyn futures::Future<Output = std::result::Result<(auth::AuthenticationData, http::response::Builder), http::response::Builder>> + std::marker::Send + 'c)>>>`

error: higher-ranked lifetime error
   --> lobby-server/src/lib.rs:568:33
    |
568 | ...                   tokio::spawn(f);
    |                       ^^^^^^^^^^^^^^^
    |
    = note: could not prove `futures::future::MapErr<TryForEach<impl futures::Stream<Item = std::result::Result<logger::LoggerMessage, errors::Error>>, [async block@lobby-server/src/lib.rs:562:41: 565:42], [closure@lobby-server/src/lib.rs:560:51: 560:69]>, [closure@lobby-server/src/lib.rs:567:46: 567:49]>: std::marker::Send`

The code here is part of a closed-source project unfortunately. I could share relevant bits and pieces upon request but I can't provide the whole thing for others to build.

cargo bisect-rustc blames b28d30e

@khuey
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khuey commented Dec 9, 2022

Reverting #105250 on top of e10201c fixes this.

@tmandry tmandry added regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. P-critical Critical priority labels Dec 20, 2022
@bors bors closed this as completed in 575b2a2 Dec 20, 2022
Swatinem added a commit to Swatinem/rust that referenced this issue Dec 30, 2022
The test was minified from the published `msf-ice:0.2.1` crate which failed in a crater run.

A faulty compiler was triggering a `higher-ranked lifetime error`:

> could not prove `[async block@...]: Send`
bors added a commit to rust-lang-ci/rust that referenced this issue Dec 30, 2022
… r=petrochenkov

Add regression test for rust-lang#105501

The test was minified from the published crate `msf-ice:0.2.1` which failed in a crater run.

A faulty compiler was triggering a `higher-ranked lifetime error`:
> could not prove `[async block@...]: Send`

The testcase has some complexity, as it has a simplified subset of `futures::StreamExt` in it, but the error is only being triggered by a few layers of nesting. For example removing the noop `then` call would have been enough to make the error go away.
Swatinem added a commit to Swatinem/rust that referenced this issue Jan 17, 2023
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <rust-lang#105501>.

The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Jan 18, 2023
Transform async `ResumeTy` in generator transform

- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors.
See <rust-lang#105501>.

The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.

---

Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/1330 CC `@bjorn3`

r? `@compiler-errors`
Swatinem added a commit to Swatinem/rust that referenced this issue Jan 19, 2023
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <rust-lang#105501>.

The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this issue Jan 19, 2023
Transform async `ResumeTy` in generator transform

- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors.
See <rust-lang#105501>.

The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.

---

Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/1330 CC `@bjorn3`

r? `@compiler-errors`
thomcc pushed a commit to tcdi/postgrestd that referenced this issue May 31, 2023
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <rust-lang/rust#105501>.

The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
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Labels
C-bug Category: This is a bug. P-critical Critical priority regression-from-stable-to-nightly Performance or correctness regression from stable to nightly.
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