Add suggestion for missing `.await` keyword #62067

cofibrant · 2019-06-22T22:39:26Z

This commit adds a suggestion diagnostic for missing .await. In order to do this, the trait Future is promoted to a lang item.

Compiling code of the form:

#![feature(async_await)]

fn take_u32(x: u32) {}

async fn make_u32() -> u32 {
    22
}

async fn foo() {
    let x = make_u32();
    take_u32(x)
}

fn main() {}

Will now result in the suggestion:

error[E0308]: mismatched types
  --> src/main.rs:11:18
   |
11 |         take_u32(x)
   |                  ^
   |                  |
   |                  expected u32, found opaque type
   |                  help: consider using `.await` here: `x.await`
   |
   = note: expected type `u32`
              found type `impl std::future::Future`

This commit does not cover chained expressions and therefore only covers the case originally pointed out in #61076. Cases I can think of that still need to be covered:

Return places for functions
Field access
Method invocation

I'm planning to submit PRs for each of these separately as and when I have figured them out.

rust-highfive · 2019-06-22T22:39:30Z

r? @matthewjasper

(rust_highfive has picked a reviewer for you, use r? to override)

src/librustc_typeck/check/mod.rs

src/test/ui/async-await/suggest-missing-await.rs

cofibrant · 2019-06-24T10:54:39Z

@matthewjasper Thank you very much for the comments! I hope this covers everything you suggested.

davidtwco

I've left a couple nit-picky reviews that you can feel free to resolve if you have the time, this looks great though!

src/test/ui/async-await/suggest-missing-await.rs

src/librustc_typeck/check/mod.rs

cofibrant · 2019-06-24T21:55:27Z

@davidtwco Thank you for the review! I've tried my best to follow your guidance. I've rebased, but haven't made any semantic changes.

matthewjasper · 2019-06-26T20:55:37Z

@bors r+

bors · 2019-06-26T20:55:38Z

📌 Commit 86ffeef has been approved by matthewjasper

bors · 2019-06-26T20:55:39Z

🌲 The tree is currently closed for pull requests below priority 999, this pull request will be tested once the tree is reopened

…jasper Add suggestion for missing `.await` keyword This commit adds a suggestion diagnostic for missing `.await`. In order to do this, the trait `Future` is promoted to a lang item. Compiling code of the form: ```rust #![feature(async_await)] fn take_u32(x: u32) {} async fn make_u32() -> u32 { 22 } async fn foo() { let x = make_u32(); take_u32(x) } fn main() {} ``` Will now result in the suggestion: ``` error[E0308]: mismatched types --> src/main.rs:11:18 | 11 | take_u32(x) | ^ | | | expected u32, found opaque type | help: consider using `.await` here: `x.await` | = note: expected type `u32` found type `impl std::future::Future` ``` This commit does not cover chained expressions and therefore only covers the case originally pointed out in rust-lang#61076. Cases I can think of that still need to be covered: - [ ] Return places for functions - [ ] Field access - [ ] Method invocation I'm planning to submit PRs for each of these separately as and when I have figured them out.

Centril · 2019-06-27T12:42:55Z

Failed in #62178 (comment), @bors r-

cofibrant · 2019-06-27T13:20:55Z

I hadn't realised that the API for HIR had changed, this should hopefully be alright to merge now (the only change in that rebase is to change get_parent_node_by_id to get_parent_node)

Centril · 2019-06-27T13:25:34Z

@bors r=matthewjasper

bors · 2019-06-27T13:25:36Z

📌 Commit 8819420 has been approved by matthewjasper

…jasper Add suggestion for missing `.await` keyword This commit adds a suggestion diagnostic for missing `.await`. In order to do this, the trait `Future` is promoted to a lang item. Compiling code of the form: ```rust #![feature(async_await)] fn take_u32(x: u32) {} async fn make_u32() -> u32 { 22 } async fn foo() { let x = make_u32(); take_u32(x) } fn main() {} ``` Will now result in the suggestion: ``` error[E0308]: mismatched types --> src/main.rs:11:18 | 11 | take_u32(x) | ^ | | | expected u32, found opaque type | help: consider using `.await` here: `x.await` | = note: expected type `u32` found type `impl std::future::Future` ``` This commit does not cover chained expressions and therefore only covers the case originally pointed out in rust-lang#61076. Cases I can think of that still need to be covered: - [ ] Return places for functions - [ ] Field access - [ ] Method invocation I'm planning to submit PRs for each of these separately as and when I have figured them out.

@ghost

Rollup of 16 pull requests Successful merges: - #61878 (improve pinning projection docs) - #62043 (Remove `FnBox`) - #62067 (Add suggestion for missing `.await` keyword) - #62076 (Updated RELEASES.md for 1.36.0) - #62102 (call out explicitly that general read needs to be called with an initialized buffer) - #62106 (Add more tests for async/await) - #62124 (refactor lexer to use idiomatic borrowing) - #62131 (libsyntax: Fix some Clippy warnings) - #62152 (Don't ICE on item in `.await` expression) - #62154 (Remove old fixme) - #62155 (Add regression test for MIR drop generation in async loops) - #62156 (Update books) - #62160 (Remove outdated question_mark_macro_sep lint) - #62164 (save-analysis: use buffered writes) - #62171 (rustc: Retry SIGILL linker invocations) - #62176 (Update RLS) Failed merges: r? @ghost

rust-highfive assigned matthewjasper Jun 22, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 22, 2019

matthewjasper reviewed Jun 23, 2019

View reviewed changes

src/librustc_typeck/check/mod.rs Outdated Show resolved Hide resolved

src/test/ui/async-await/suggest-missing-await.rs Outdated Show resolved Hide resolved

davidtwco approved these changes Jun 24, 2019

View reviewed changes

src/test/ui/async-await/suggest-missing-await.rs Show resolved Hide resolved

src/test/ui/async-await/suggest-missing-await.rs Outdated Show resolved Hide resolved

src/librustc_typeck/check/mod.rs Show resolved Hide resolved

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 26, 2019

Centril mentioned this pull request Jun 27, 2019

Rollup of 16 pull requests #62178

Closed

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 27, 2019

Add suggestion for missing .await keyword

8819420

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 27, 2019

Centril mentioned this pull request Jun 27, 2019

Rollup of 16 pull requests #62182

Closed

Centril mentioned this pull request Jun 27, 2019

Rollup of 16 pull requests #62192

Merged

bors merged commit 8819420 into rust-lang:master Jun 28, 2019

cofibrant deleted the await_diagnostic branch June 28, 2019 17:41

cofibrant mentioned this pull request Jul 31, 2019

suggest await for future-related type errors #61076

Closed

Aaron1011 mentioned this pull request Dec 3, 2019

Slightly incorrect help message with mismatched typs in async code #66910

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Add suggestion for missing `.await` keyword #62067

Add suggestion for missing `.await` keyword #62067

Uh oh!

cofibrant commented Jun 22, 2019 •

edited

Loading

Uh oh!

rust-highfive commented Jun 22, 2019

Uh oh!

Uh oh!

Uh oh!

cofibrant commented Jun 24, 2019

Uh oh!

davidtwco left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

cofibrant commented Jun 24, 2019

Uh oh!

matthewjasper commented Jun 26, 2019

Uh oh!

bors commented Jun 26, 2019

Uh oh!

bors commented Jun 26, 2019

Uh oh!

Centril commented Jun 27, 2019

Uh oh!

cofibrant commented Jun 27, 2019 •

edited

Loading

Uh oh!

Centril commented Jun 27, 2019

Uh oh!

bors commented Jun 27, 2019

Uh oh!

Uh oh!

Add suggestion for missing .await keyword #62067

Add suggestion for missing .await keyword #62067

Uh oh!

Conversation

cofibrant commented Jun 22, 2019 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rust-highfive commented Jun 22, 2019

Uh oh!

Uh oh!

Uh oh!

cofibrant commented Jun 24, 2019

Uh oh!

davidtwco left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

cofibrant commented Jun 24, 2019

Uh oh!

matthewjasper commented Jun 26, 2019

Uh oh!

bors commented Jun 26, 2019

Uh oh!

bors commented Jun 26, 2019

Uh oh!

Centril commented Jun 27, 2019

Uh oh!

cofibrant commented Jun 27, 2019 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Centril commented Jun 27, 2019

Uh oh!

bors commented Jun 27, 2019

Uh oh!

Uh oh!

Add suggestion for missing `.await` keyword #62067

Add suggestion for missing `.await` keyword #62067

cofibrant commented Jun 22, 2019 •

edited

Loading

cofibrant commented Jun 27, 2019 •

edited

Loading