Tweak match arm semicolon removal suggestion to account for futures #78214

estebank · 2020-10-22T03:00:36Z

Tweak and extend "use .await" suggestions
Suggest removal of semicolon on prior match arm
Account for impl Future when suggesting semicolon removal
Silence some errors when encountering await foo()? as can't be certain what the intent was

Thanks to https://twitter.com/a_hoverbear/status/1318960787105353728 for pointing this out!

rust-highfive · 2020-10-22T03:00:39Z

r? @eddyb

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estebank · 2020-10-22T03:00:48Z

r? @oli-obk

src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr

compiler/rustc_typeck/src/check/_match.rs

compiler/rustc_middle/src/traits/mod.rs

compiler/rustc_typeck/src/check/_match.rs

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

oli-obk · 2020-10-23T14:31:10Z

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

-                                "consider using `.await` here",
-                                format!("{}.await?", snippet.trim_end_matches('?')),
+                            err.span_suggestion_verbose(
+                                span.with_hi(span.hi() - BytePos(1)).shrink_to_hi(),


This is the second occurrence of this pattern... but I have no idea how to generalize it in a useful way...

We could add a method Span::shrink_by_one(Self) to avoid the BytePos play, but two calls would still be needed.

yea, that's one solution, but I don't like it unless we have more such - BytePos(1) in rustc or clippy.

We have a few in rustc, but I try to avoid them like the plague* whenever feasible.

*Really need to stop using that phrase, some people embrace the plague.

oli-obk · 2020-10-23T14:33:36Z

r=me after a rebase

…stions

oli-obk · 2020-10-23T16:29:21Z

@bors r+

bors · 2020-10-23T16:29:23Z

📌 Commit f5d7443 has been approved by oli-obk

Tweak match arm semicolon removal suggestion to account for futures * Tweak and extend "use `.await`" suggestions * Suggest removal of semicolon on prior match arm * Account for `impl Future` when suggesting semicolon removal * Silence some errors when encountering `await foo()?` as can't be certain what the intent was *Thanks to https://twitter.com/a_hoverbear/status/1318960787105353728 for pointing this out!*

Rollup of 10 pull requests Successful merges: - rust-lang#74477 (`#[deny(unsafe_op_in_unsafe_fn)]` in sys/wasm) - rust-lang#77836 (transmute_copy: explain that alignment is handled correctly) - rust-lang#78126 (Properly define va_arg and va_list for aarch64-apple-darwin) - rust-lang#78137 (Initialize tracing subscriber in compiletest tool) - rust-lang#78161 (Add issue template link to IRLO) - rust-lang#78214 (Tweak match arm semicolon removal suggestion to account for futures) - rust-lang#78247 (Fix rust-lang#78192) - rust-lang#78252 (Add codegen test for rust-lang#45964) - rust-lang#78268 (Do not try to report on closures to avoid ICE) - rust-lang#78295 (Add some regression tests) Failed merges: r? `@ghost`

@oli-obk

Suggest calling await on method call and field access When encountering a failing method or field resolution on a `Future`, look at the `Output` and try the same operation on it. If successful, suggest calling `.await` on the `Future`. This had already been introduced in rust-lang#72784, but at some point they stopped working. Built on top of rust-lang#78214, only last commit is relevant. r? @oli-obk

rust-highfive assigned eddyb Oct 22, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 22, 2020

rust-highfive assigned oli-obk and unassigned eddyb Oct 22, 2020

csmoe reviewed Oct 22, 2020

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