Confusing suggestion on incorrect closing `}` by kper · Pull Request #70633 · rust-lang/rust

kper · 2020-03-31T20:20:25Z

Compiler returns

error: unexpected closing delimiter: `}`
--> main.rs:20:1
|
9 | ErrorHandled::Reported => {}
| -- this block is empty, you might have not meant to close it temp
...
20 | }
| ^ unexpected closing delimiter
error: aborting due to previous error

…iter #70583

rust-highfive · 2020-03-31T20:20:28Z

r? @ecstatic-morse

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

ecstatic-morse · 2020-03-31T21:25:22Z

@kper while the suggestion has some false positives, I don't think that alone is a good enough reason to remove it entirely. After #69708, there is no test that emits this suggestion, so r? @estebank to weigh in on removal.

estebank · 2020-04-01T00:13:16Z

Oh, I though we had other tests covering this... that's my bad.

I can be on favor of a better heuristic, for users of some editors this suggestion has been helpful. @kper could you give us an idea of what the code was when you got the bogus suggestion? We could, for example, detect empty blocks that are fully valid match arms and never suggest those. I think that's the most common source of these misleading suggestions.

kper · 2020-04-01T06:04:49Z

@estebank oh sorry, the PR didn't link the issue. (#70583)
The code was:

pub enum ErrorHandled {
Reported,
TooGeneric,
}
impl ErrorHandled {
pub fn assert_reported(self) {
match self {
ErrorHandled::Reported => {}
ErrorHandled::TooGeneric => panic!(),
}
}
}
fn struct_generic(x: Vec<i32>) {
for v in x {
println!("{}", v);
}
} // <-- incorrect closing brace
}

We could, for example, detect empty blocks that are fully valid match arms and never suggest those. I think that's the most common source of these misleading suggestions.

Well the reason why I removed it, was the compiler returns this error message this block is empty..., although this block is somewhere else.

empty blocks that are fully valid match arms

Ok, I will try that, so I'll revert the removal.

Is there anything else, I should put there instead? Because after the fix, the compiler will return a message which doesn't provide a suggestion.

error: unexpected closing delimiter: `}`
--> main.rs:20:1
|
20 | }
| ^ unexpected closing delimiter
error: aborting due to previous error

…ng delimiter #70583" This reverts commit 811d817.

estebank · 2020-04-01T17:17:53Z

@kper An option would be to keep track of when the last properly formed Item ended and ignore Spans in self.last_delim_empty_block_spans that appear before then. This would make your case do the right thing.

Also, for this case, ideally we would have output like

error: unexpected closing delimiter: `}`
--> main.rs:20:1
|
16 | fn struct_generic(x: Vec<i32>) {
| - this opening brace...
...
19 | } // <-- incorrect closing brace
| - ...matches this closing brace, but they don't match indentation
20 | }
| ^ unexpected closing delimiter

…t properly closed block.

rust-highfive · 2020-04-02T09:00:59Z

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2020-04-02T07:20:05.7142906Z ========================== Starting Command Output ===========================
2020-04-02T07:20:05.7146377Z [command]/bin/bash --noprofile --norc /home/vsts/work/_temp/822f1598-9e46-4013-9af3-411415249b5e.sh
2020-04-02T07:20:05.7146776Z 2020-04-02T07:20:05.7151018Z ##[section]Finishing: Disable git automatic line ending conversion
2020-04-02T07:20:05.7169856Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70633/merge to s
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2020-04-02T07:20:05.7173715Z Version : 1.0.0
2020-04-02T07:20:05.7173916Z Author : Microsoft
---
2020-04-02T07:20:06.7064956Z ##[command]git remote add origin https://github.com/rust-lang/rust
2020-04-02T07:20:06.7070419Z ##[command]git config gc.auto 0
2020-04-02T07:20:06.7074030Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2020-04-02T07:20:06.7077391Z ##[command]git config --get-all http.proxy
2020-04-02T07:20:06.7083409Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/70633/merge:refs/remotes/pull/70633/merge
---
2020-04-02T07:22:10.4817877Z ---> 3fc1b512c57b
2020-04-02T07:22:10.4818171Z Step 6/7 : ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
2020-04-02T07:22:10.4822009Z ---> Using cache
2020-04-02T07:22:10.4822478Z ---> 5ee4295733f4
2020-04-02T07:22:10.4824139Z Step 7/7 : ENV SCRIPT python2.7 ../x.py test src/tools/expand-yaml-anchors && python2.7 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu && python2.7 ../x.py build --stage 0 src/tools/build-manifest && python2.7 ../x.py test --stage 0 src/tools/compiletest && python2.7 ../x.py test src/tools/tidy && /scripts/validate-toolstate.sh
2020-04-02T07:22:10.4827901Z ---> 3d07a0fa42fe
2020-04-02T07:22:10.4872309Z Successfully built 3d07a0fa42fe
2020-04-02T07:22:10.4934252Z Successfully tagged rust-ci:latest
2020-04-02T07:22:10.5219923Z Built container sha256:3d07a0fa42feb5754fc13bb2f7010ebe13e4b8b8cdbebed0c75d8da320c8c8ad
2020-04-02T07:22:10.5219923Z Built container sha256:3d07a0fa42feb5754fc13bb2f7010ebe13e4b8b8cdbebed0c75d8da320c8c8ad
2020-04-02T07:22:10.5235713Z Looks like docker image is the same as before, not uploading
2020-04-02T07:22:15.9402785Z [CI_JOB_NAME=mingw-check]
2020-04-02T07:22:15.9614623Z [CI_JOB_NAME=mingw-check]
2020-04-02T07:22:15.9643928Z == clock drift check ==
2020-04-02T07:22:15.9653830Z local time: Thu Apr 2 07:22:15 UTC 2020
2020-04-02T07:22:16.1251143Z network time: Thu, 02 Apr 2020 07:22:16 GMT
2020-04-02T07:22:16.1277550Z Starting sccache server...
2020-04-02T07:22:16.2153696Z configure: processing command line
2020-04-02T07:22:16.2154024Z configure: 2020-04-02T07:22:16.2154978Z configure: rust.parallel-compiler := True
---
2020-04-02T07:25:36.6697857Z Checking rustc_feature v0.0.0 (/checkout/src/librustc_feature)
2020-04-02T07:25:36.8103852Z Checking fmt_macros v0.0.0 (/checkout/src/libfmt_macros)
2020-04-02T07:25:36.9927731Z Checking rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
2020-04-02T07:25:37.0434268Z Checking rustc_hir v0.0.0 (/checkout/src/librustc_hir)
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2020-04-02T07:25:40.1374865Z Checking rustc_parse v0.0.0 (/checkout/src/librustc_parse)
2020-04-02T07:25:41.9826035Z Checking rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
2020-04-02T07:25:42.4013503Z Checking rustc_ast_lowering v0.0.0 (/checkout/src/librustc_ast_lowering)
---
2020-04-02T07:27:22.2885490Z configure: build.locked-deps := True
2020-04-02T07:27:22.2885931Z configure: llvm.ccache := sccache
2020-04-02T07:27:22.2886549Z configure: build.cargo-native-static := True
2020-04-02T07:27:22.2887159Z configure: dist.missing-tools := True
2020-04-02T07:27:22.2887901Z configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
2020-04-02T07:27:22.2888738Z configure: writing `config.toml` in current directory
2020-04-02T07:27:22.2889090Z configure: 2020-04-02T07:27:22.2889620Z configure: run `python /checkout/x.py --help`
2020-04-02T07:27:22.2889989Z configure: ---
2020-04-02T07:28:39.0567812Z Hugepagesize: 2048 kB
2020-04-02T07:28:39.0568049Z DirectMap4k: 126912 kB
2020-04-02T07:28:39.0568274Z DirectMap2M: 1970176 kB
2020-04-02T07:28:39.0568498Z DirectMap1G: 7340032 kB
2020-04-02T07:28:39.0569821Z + python2.7 ../x.py test src/tools/expand-yaml-anchors
2020-04-02T07:28:40.3166692Z Ensuring the YAML anchors in the GitHub Actions config were expanded
2020-04-02T07:28:40.3166692Z Ensuring the YAML anchors in the GitHub Actions config were expanded
2020-04-02T07:28:40.3177841Z Building stage0 tool expand-yaml-anchors (x86_64-unknown-linux-gnu)
2020-04-02T07:28:40.5407552Z Compiling unicode-xid v0.2.0
2020-04-02T07:28:40.6557660Z Compiling syn v1.0.11
2020-04-02T07:28:41.4233969Z Compiling linked-hash-map v0.5.2
2020-04-02T07:28:41.4510613Z Compiling lazy_static v1.4.0
2020-04-02T07:28:41.4510613Z Compiling lazy_static v1.4.0
2020-04-02T07:28:41.6320901Z Compiling yaml-rust v0.4.3
2020-04-02T07:28:45.6739728Z Compiling quote v1.0.2
2020-04-02T07:28:58.9064184Z Compiling thiserror-impl v1.0.5
2020-04-02T07:29:03.2095599Z Compiling thiserror v1.0.5
2020-04-02T07:29:03.2703610Z Compiling yaml-merge-keys v0.4.0
2020-04-02T07:29:04.3340618Z Compiling expand-yaml-anchors v0.1.0 (/checkout/src/tools/expand-yaml-anchors)
2020-04-02T07:29:05.8386025Z Build completed successfully in 0:00:26
2020-04-02T07:29:05.8393764Z + python2.7 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu
2020-04-02T07:29:06.0667928Z Finished dev [unoptimized] target(s) in 0.16s
2020-04-02T07:29:07.1265499Z Checking rustdoc artifacts (x86_64-unknown-linux-gnu -> i686-pc-windows-gnu)
---
2020-04-02T07:31:05.1849284Z Checking rustc_feature v0.0.0 (/checkout/src/librustc_feature)
2020-04-02T07:31:05.4353637Z Checking fmt_macros v0.0.0 (/checkout/src/libfmt_macros)
2020-04-02T07:31:05.5650706Z Checking rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
2020-04-02T07:31:05.6290555Z Checking rustc_hir v0.0.0 (/checkout/src/librustc_hir)
2020-04-02T07:31:06.1238873Z Checking rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
2020-04-02T07:31:08.2146204Z Checking rustc_attr v0.0.0 (/checkout/src/librustc_attr)
2020-04-02T07:31:08.6565059Z Checking rustc_parse v0.0.0 (/checkout/src/librustc_parse)
2020-04-02T07:31:10.6767307Z Checking rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
2020-04-02T07:31:11.1146576Z Checking rustc_ast_lowering v0.0.0 (/checkout/src/librustc_ast_lowering)
---
2020-04-02T07:34:34.6881849Z Compiling cargo_metadata v0.9.1
2020-04-02T07:34:38.0974334Z Compiling tidy v0.1.0 (/checkout/src/tools/tidy)
2020-04-02T07:34:48.2259043Z Finished release [optimized] target(s) in 22.93s
2020-04-02T07:34:48.2360674Z tidy check
2020-04-02T07:34:48.5800103Z tidy error: /checkout/src/test/ui/parser/issue-70583-block-is-empty-2.rs:9: trailing whitespace
2020-04-02T07:34:48.5801020Z tidy error: /checkout/src/test/ui/parser/issue-70583-block-is-empty-2.rs:10: line longer than 100 chars
2020-04-02T07:34:48.5959250Z tidy error: /checkout/src/test/ui/parser/issue-70583-block-is-empty-1.rs:19: trailing whitespace
2020-04-02T07:34:55.8765156Z Found 491 error codes
2020-04-02T07:34:55.8765978Z Found 0 error codes with no tests
2020-04-02T07:34:55.8766399Z Done!
2020-04-02T07:34:55.8771095Z some tidy checks failed
2020-04-02T07:34:55.8771095Z some tidy checks failed
2020-04-02T07:34:55.8774016Z 2020-04-02T07:34:55.8774346Z 2020-04-02T07:34:55.8776306Z command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo"
2020-04-02T07:34:55.8777528Z 2020-04-02T07:34:55.8777796Z 2020-04-02T07:34:55.8780988Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
2020-04-02T07:34:55.8781643Z Build completed unsuccessfully in 0:00:31
2020-04-02T07:34:55.8781643Z Build completed unsuccessfully in 0:00:31
2020-04-02T07:34:55.8822358Z == clock drift check ==
2020-04-02T07:34:55.8835992Z local time: Thu Apr 2 07:34:55 UTC 2020
2020-04-02T07:34:55.9430709Z network time: Thu, 02 Apr 2020 07:34:55 GMT
2020-04-02T07:34:57.5217839Z 2020-04-02T07:34:57.5217839Z 2020-04-02T07:34:57.5279374Z ##[error]Bash exited with code '1'.
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2020-04-02T07:34:57.5349558Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70633/merge to s
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kper · 2020-04-02T10:46:47Z

Thanks @estebank for the hint. Basically, that is what I'm doing right now. I keep track of my delim_tokens and then I check if the empty bracket's span is in that range.

kper · 2020-04-02T10:53:01Z

But, I have still some troubles with the tidy check.

This is one of my tests. However, ERROR this block is empty, you might have not mean to close it seems too long for the tidy check. Is there a way to force it?

pub enum ErrorHandled {
Reported,
TooGeneric,
}
impl ErrorHandled {
pub fn assert_reported(self) {
match self {
ErrorHandled::Reported => {}} //^~ ERROR this block is empty, you might have not mean to close it
ErrorHandled::TooGeneric => panic!(),
}
}
} //~ ERROR unexpected closing delimiter: `}`

PS: I've seen the typo

kper · 2020-04-04T12:52:20Z

However, ERROR this block is empty, you might have not mean to close it seems too long for the tidy check. Is there a way to force it?

Nevermind, I dropped a word.

Those are the new error message after the PR. My changes led to changes in different tests too. I hope, that is fine. If not, please let me know.

I dropped the term "but they don't match indentation" from your proposal because it might cause confusion in some cases (the last example below where the indentation is correct).

LL | fn struct_generic(x: Vec<i32>) {
| - this opening brace...
...
LL | }
| - ...matches this closing brace
LL | }
| ^ unexpected closing delimiter

match self {
ErrorHandled::Reported => {}}
//^~ ERROR block is empty, you might have not meant to close it
ErrorHandled::TooGeneric => panic!(),
}
}
} //~ ERROR unexpected closing delimiter: `}`

LL | fn main() {
| - this opening brace...
...
LL | }
| - ...matches this closing brace
LL | }
| ^ unexpected closing delimiter

LL | fn main() {
| - this opening brace...
LL | LL | }
| - ...matches this closing brace
LL | let _ = ();
LL | }
| ^ unexpected closing delimiter

estebank · 2020-04-23T01:33:41Z

@bors r+

bors · 2020-04-23T01:33:43Z

📌 Commit f96b92f has been approved by estebank

@ghost

Rollup of 7 pull requests Successful merges: - rust-lang#70633 (Confusing suggestion on incorrect closing `}`) - rust-lang#71404 (Don't fuse Chain in its second iterator) - rust-lang#71408 (Check code blocks tags) - rust-lang#71442 (Add a "by reference" adaptor for `AllocRef`) - rust-lang#71446 (Only use read_unaligned in transmute_copy if necessary) - rust-lang#71470 (Fix doc links) - rust-lang#71479 (add back Scalar::null_ptr) Failed merges: r? @ghost

Dropping "block is empty..." error message on incorrect closing delim…
811d817
…iter #70583

rust-highfive assigned ecstatic-morse Mar 31, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 31, 2020

rust-highfive assigned estebank and unassigned ecstatic-morse Mar 31, 2020

Revert "Dropping "block is empty..." error message on incorrect closi…
af16794
…ng delimiter #70583" This reverts commit 811d817.

kper added 2 commits April 2, 2020 06:42

Check if the suggestion's this block is empty... span is in the las…
b85d588
…t properly closed block.

Writing tests
053a696

kper added 4 commits April 3, 2020 07:24

Fixing tests
d5cba6c

Show open and closed braces of last proper block
e21d101

Drop this in error message to not reach 100 characters
2c6f846

Run fmt
f96b92f

kper changed the title ~~(WIP) Confusing suggestion on incorrect closing }~~Confusing suggestion on incorrect closing }Apr 20, 2020

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 Apr 23, 2020

Dylan-DPC-zz mentioned this pull request Apr 23, 2020
Rollup of 7 pull requests #71483
Merged

bors merged commit 1d3d80f into rust-lang:masterApr 23, 2020

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Confusing suggestion on incorrect closing `}` - #70633

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