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std::r#await! macro cannot be used even if #![feature(await_macro)] is enabled #60660

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std::r#await! macro cannot be used even if #![feature(await_macro)] is enabled#60660
Labels
A-async-awaitArea: Async & AwaitC-bugCategory: This is a bug.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

Description

@taiki-e
taiki-e
opened on May 9, 2019

Code:

#![feature(async_await, await_macro)]

use std::r#await as std_await;

async fn foo() {}

async fn bar() {
    std_await!(foo())
}

Error:

error[E0658]: macro std_await! is unstable
 --> code\src\lib.rs:8:5
  |
8 |     std_await!(noop())
  |     ^^^^^^^^^^^^^^^^^^
  |
  = note: for more information, see https://github.com/rust-lang/rust/issues/50547
  = help: add #![feature(await_macro)] to the crate attributes to enable

error[E0727]: `async` generators are not yet supported
 --> code\src\lib.rs:7:16
  |
7 |   async fn foo() {
  |  ________________^
8 | |     std_await!(noop())
9 | | }
  | |_^

error: aborting due to 2 previous errors

Seems the second error relates to the fact that std::await is still defined using yield.

rust/src/libstd/macros.rs

Line 378 in 9f83961

yield

Rustc version: rustc 1.36.0-nightly (3f5152e 2019-05-08)

cc @cramertj

Activity

  1. taiki-e commented on May 9, 2019

    @taiki-e
    taiki-e
    on May 9, 2019
    MemberAuthor

    @rustbot modify labels: A-async-await, T-compiler.

  2. rustbot
    added
    A-async-awaitArea: Async & Await
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    on May 9, 2019
  3. jonas-schievink
    added
    C-bugCategory: This is a bug.
    on May 9, 2019

  4. taiki-e commented on May 9, 2019

    @taiki-e
    taiki-e
    on May 9, 2019
    MemberAuthor

    Reduced:

    #![feature(async_await, await_macro)]

async fn foo() {}

async fn bar() {
    std::r#await!(foo())
}

    Seems the actual problem is not about importing but using std::r#await.

  5. taiki-e
    changed the title [-]If import await! macro as another name, it cannot be used even if #![feature(await_macro)] is enabled[/-] [+]std::r#await! macro cannot be used even if #![feature(await_macro)] is enabled[/+] on May 9, 2019

  6. cramertj commented on May 9, 2019

    @cramertj
    cramertj
    on May 9, 2019
    Member

    Yeah, I wouldn't expect the old macro to work anymore-- intentionally.

  7. cramertj
    closed this as completedon May 9, 2019

  8. cramertj commented on May 9, 2019

    @cramertj
    cramertj
    on May 9, 2019
    Member

    Opened #60675 to remove the old macro to prevent further confusion.

  9. Centril
    added a commit that references this issue on May 9, 2019

    Rollup merge of rust-lang#60675 - cramertj:no-await-macro, r=nikomats…

    f6df1f6
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