Fix incorrect pattern warning "unreachable pattern" by AminArria · Pull Request #70413 · rust-lang/rust

AminArria · 2020-03-25T23:43:28Z

Added is_under_guard parameter to _match::is_useful and only add it to the matrix if false

Tested with:

#![feature(or_patterns)]fnmain(){match(3,42){(a,_) | (_,a)if a > 10 => {println!("{}", a)}
_ => ()}matchSome((3,42)){Some((a, _)) | Some((_, a))if a > 10 => {println!("{}", a)}
_ => ()}matchSome((3,42)){Some((a, _) | (_, a))if a > 10 => {println!("{}", a)}
_ => ()}}

rust-highfive · 2020-03-25T23:43:31Z

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @estebank (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

Centril

Looks good. :)

Please also add the test cases mentioned in the OP in src/test/ui/or-patterns/issue-70413-no-unreachable-pat-and-guard.rs, with #![deny(unreachable_patterns)] and write // check-pass at the top of the file. Also make sure to ./x.py test --stage 1 --bless --pass check src/test/ui to adjust the fallout in UI tests (see also https://rustc-dev-guide.rust-lang.org/tests/adding.html).

You'll also need to run ./x.py fmt to pacify the rustfmt checks in CI.

Centril · 2020-03-25T23:52:19Z

Can you leave a note re. the false in this case?

Added in 4b1aa9fa

Centril · 2020-03-25T23:58:52Z

r? @varkor
cc @Nadrieril

Centril · 2020-03-26T00:31:43Z

Maybe add a comment here as well re. the purpose of this check.

Added in 4b1aa9fa

rust-highfive · 2020-03-26T01:43:15Z

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

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2020-03-25T23:44:53.9275302Z ========================== Starting Command Output ===========================
2020-03-25T23:44:53.9278194Z [command]/bin/bash --noprofile --norc /home/vsts/work/_temp/43a298fa-30ed-4420-a21d-4c6ab9484e7c.sh
2020-03-25T23:44:53.9278507Z 2020-03-25T23:44:53.9282777Z ##[section]Finishing: Disable git automatic line ending conversion
2020-03-25T23:44:53.9303785Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70413/merge to s
2020-03-25T23:44:53.9307043Z Task : Get sources
2020-03-25T23:44:53.9307382Z Description : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-03-25T23:44:53.9307692Z Version : 1.0.0
2020-03-25T23:44:53.9307903Z Author : Microsoft
---
2020-03-25T23:44:54.9230413Z ##[command]git remote add origin https://github.com/rust-lang/rust
2020-03-25T23:44:54.9236632Z ##[command]git config gc.auto 0
2020-03-25T23:44:54.9242079Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2020-03-25T23:44:54.9246290Z ##[command]git config --get-all http.proxy
2020-03-25T23:44:54.9254381Z ##[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/70413/merge:refs/remotes/pull/70413/merge
---
2020-03-25T23:47:10.4059928Z ---> 3fc1b512c57b
2020-03-25T23:47:10.4060260Z Step 6/7 : ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
2020-03-25T23:47:10.4062092Z ---> Using cache
2020-03-25T23:47:10.4062514Z ---> 5ee4295733f4
2020-03-25T23:47:10.4064168Z 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
2020-03-25T23:47:10.4069047Z ---> 3d07a0fa42fe
2020-03-25T23:47:10.4105994Z Successfully built 3d07a0fa42fe
2020-03-25T23:47:10.4140880Z Successfully tagged rust-ci:latest
2020-03-25T23:47:10.4426942Z Built container sha256:3d07a0fa42feb5754fc13bb2f7010ebe13e4b8b8cdbebed0c75d8da320c8c8ad
---
2020-03-25T23:50:54.7570973Z Checking rustc_attr v0.0.0 (/checkout/src/librustc_attr)
2020-03-25T23:50:55.2068054Z Checking rustc_parse v0.0.0 (/checkout/src/librustc_parse)
2020-03-25T23:50:57.1318526Z Checking rustc_ast_passes v0.0.0 (/checkout/src/librustc_ast_passes)
2020-03-25T23:50:57.7926196Z Checking rustc_expand v0.0.0 (/checkout/src/librustc_expand)
2020-03-25T23:50:57.8112059Z Checking rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
2020-03-25T23:50:59.4300418Z Checking rustc_builtin_macros v0.0.0 (/checkout/src/librustc_builtin_macros)
2020-03-25T23:51:18.7683350Z Checking rustc_infer v0.0.0 (/checkout/src/librustc_infer)
2020-03-25T23:51:22.0334555Z Checking rustc_save_analysis v0.0.0 (/checkout/src/librustc_save_analysis)
2020-03-25T23:51:22.3277445Z Checking rustc_symbol_mangling v0.0.0 (/checkout/src/librustc_symbol_mangling)
---
2020-03-25T23:52:43.8108705Z configure: build.locked-deps := True
2020-03-25T23:52:43.8109026Z configure: llvm.ccache := sccache
2020-03-25T23:52:43.8109521Z configure: build.cargo-native-static := True
2020-03-25T23:52:43.8110037Z configure: dist.missing-tools := True
2020-03-25T23:52:43.8110649Z configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
2020-03-25T23:52:43.8111229Z configure: writing `config.toml` in current directory
2020-03-25T23:52:43.8111472Z configure: 2020-03-25T23:52:43.8111905Z configure: run `python /checkout/x.py --help`
2020-03-25T23:52:43.8112137Z configure: ---
2020-03-25T23:54:09.2252943Z Hugepagesize: 2048 kB
2020-03-25T23:54:09.2253186Z DirectMap4k: 126912 kB
2020-03-25T23:54:09.2253411Z DirectMap2M: 4067328 kB
2020-03-25T23:54:09.2253636Z DirectMap1G: 5242880 kB
2020-03-25T23:54:09.2304915Z + python2.7 ../x.py test src/tools/expand-yaml-anchors
2020-03-25T23:54:10.5535603Z Ensuring the YAML anchors in the GitHub Actions config were expanded
2020-03-25T23:54:10.5535603Z Ensuring the YAML anchors in the GitHub Actions config were expanded
2020-03-25T23:54:10.5540469Z Building stage0 tool expand-yaml-anchors (x86_64-unknown-linux-gnu)
2020-03-25T23:54:10.7896568Z Compiling unicode-xid v0.2.0
2020-03-25T23:54:10.9315620Z Compiling syn v1.0.11
2020-03-25T23:54:11.7521340Z Compiling linked-hash-map v0.5.2
2020-03-25T23:54:11.7871651Z Compiling lazy_static v1.4.0
2020-03-25T23:54:11.7871651Z Compiling lazy_static v1.4.0
2020-03-25T23:54:11.9841109Z Compiling yaml-rust v0.4.3
2020-03-25T23:54:16.1702869Z Compiling quote v1.0.2
2020-03-25T23:54:30.1518837Z Compiling thiserror-impl v1.0.5
2020-03-25T23:54:34.7677264Z Compiling thiserror v1.0.5
2020-03-25T23:54:34.8272056Z Compiling yaml-merge-keys v0.4.0
2020-03-25T23:54:35.9996734Z Compiling expand-yaml-anchors v0.1.0 (/checkout/src/tools/expand-yaml-anchors)
2020-03-25T23:54:38.1228939Z Build completed successfully in 0:00:28
2020-03-25T23:54:38.1236609Z + python2.7 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu
2020-03-25T23:54:38.3657862Z Finished dev [unoptimized] target(s) in 0.17s
2020-03-25T23:54:39.4454511Z Checking rustdoc artifacts (x86_64-unknown-linux-gnu -> i686-pc-windows-gnu)
---
2020-03-25T23:56:41.2191452Z Checking rustc_attr v0.0.0 (/checkout/src/librustc_attr)
2020-03-25T23:56:41.6919391Z Checking rustc_parse v0.0.0 (/checkout/src/librustc_parse)
2020-03-25T23:56:43.7171106Z Checking rustc_ast_passes v0.0.0 (/checkout/src/librustc_ast_passes)
2020-03-25T23:56:44.4153234Z Checking rustc_expand v0.0.0 (/checkout/src/librustc_expand)
2020-03-25T23:56:44.5212481Z Checking rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
2020-03-25T23:56:46.2333916Z Checking rustc_builtin_macros v0.0.0 (/checkout/src/librustc_builtin_macros)
2020-03-25T23:57:06.0593987Z Checking rustc_infer v0.0.0 (/checkout/src/librustc_infer)
2020-03-25T23:57:09.0131962Z Checking rustc_save_analysis v0.0.0 (/checkout/src/librustc_save_analysis)
2020-03-25T23:57:09.0316439Z Checking rustc_symbol_mangling v0.0.0 (/checkout/src/librustc_symbol_mangling)
---
2020-03-26T00:00:50.2016647Z Diff in /checkout/src/librustc_mir_build/hair/pattern/_match.rs at line 1719:
2020-03-26T00:00:50.2017494Z Some(hir_id),
2020-03-26T00:00:50.2017908Z )
2020-03-26T00:00:50.2018278Z .into_iter()
2020-03-26T00:00:50.2019884Z - .map(|c| is_useful_specialized(cx, matrix, v, c, pcx.ty, witness_preference, hir_id, is_under_guard))
2020-03-26T00:00:50.2021247Z + .map(|c| {
2020-03-26T00:00:50.2021653Z + is_useful_specialized(
2020-03-26T00:00:50.2022333Z + matrix,
2020-03-26T00:00:50.2022646Z + v,
2020-03-26T00:00:50.2022961Z + c,
2020-03-26T00:00:50.2025991Z + pcx.ty,
2020-03-26T00:00:50.2025991Z + pcx.ty,
2020-03-26T00:00:50.2026417Z + witness_preference,
2020-03-26T00:00:50.2026793Z + hir_id,
2020-03-26T00:00:50.2027129Z + is_under_guard,
2020-03-26T00:00:50.2027447Z + )
2020-03-26T00:00:50.2027742Z + })
2020-03-26T00:00:50.2028076Z .find(|result| result.is_useful())
2020-03-26T00:00:50.2028440Z .unwrap_or(NotUseful)
2020-03-26T00:00:50.2029167Z Diff in /checkout/src/librustc_mir_build/hair/pattern/_match.rs at line 1753:
2020-03-26T00:00:50.2029167Z Diff in /checkout/src/librustc_mir_build/hair/pattern/_match.rs at line 1753:
2020-03-26T00:00:50.2029752Z split_grouped_constructors(cx.tcx, cx.param_env, pcx, all_ctors, matrix, DUMMY_SP, None)
2020-03-26T00:00:50.2030569Z .map(|c| {
2020-03-26T00:00:50.2030569Z .map(|c| {
2020-03-26T00:00:50.2031661Z - is_useful_specialized(cx, matrix, v, c, pcx.ty, witness_preference, hir_id, is_under_guard)
2020-03-26T00:00:50.2038189Z + is_useful_specialized(
2020-03-26T00:00:50.2038993Z + matrix,
2020-03-26T00:00:50.2039331Z + v,
2020-03-26T00:00:50.2039680Z + c,
2020-03-26T00:00:50.2040022Z + pcx.ty,
2020-03-26T00:00:50.2040022Z + pcx.ty,
2020-03-26T00:00:50.2040394Z + witness_preference,
2020-03-26T00:00:50.2093072Z + hir_id,
2020-03-26T00:00:50.2093864Z + is_under_guard,
2020-03-26T00:00:50.2094266Z + )
2020-03-26T00:00:50.2094608Z })
2020-03-26T00:00:50.2094972Z .find(|result| result.is_useful())
2020-03-26T00:00:50.2095367Z .unwrap_or(NotUseful)
2020-03-26T00:00:50.2095824Z Diff in /checkout/src/librustc_mir_build/hair/pattern/_match.rs at line 1760:
2020-03-26T00:00:50.2096228Z } else {
2020-03-26T00:00:50.2096605Z let matrix = matrix.specialize_wildcard();
2020-03-26T00:00:50.2096996Z let v = v.to_tail();
2020-03-26T00:00:50.2097979Z - let usefulness = is_useful(cx, &matrix, &v, witness_preference, hir_id, is_under_guard, false);
2020-03-26T00:00:50.2098496Z + let usefulness =
2020-03-26T00:00:50.2098951Z + is_useful(cx, &matrix, &v, witness_preference, hir_id, is_under_guard, false);
2020-03-26T00:00:50.2099351Z 2020-03-26T00:00:50.2099939Z // In this case, there's at least one "free"
2020-03-26T00:00:50.2100398Z // constructor that is only matched against by
2020-03-26T00:00:50.2103348Z Running `"/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/rustfmt" "--config-path" "/checkout" "--edition" "2018" "--unstable-features" "--skip-children" "--check" "/checkout/src/librustc_mir_build/hair/pattern/_match.rs"` failed.
2020-03-26T00:00:50.2104635Z If you're running `tidy`, try again with `--bless` flag. Or, you just want to format code, run `./x.py fmt` instead.
2020-03-26T00:00:50.2105761Z Build completed unsuccessfully in 0:00:41
2020-03-26T00:00:50.2106134Z == clock drift check ==
2020-03-26T00:00:50.2113389Z local time: Thu Mar 26 00:00:50 UTC 2020
2020-03-26T00:00:50.4990636Z network time: Thu, 26 Mar 2020 00:00:50 GMT
2020-03-26T00:00:50.4990636Z network time: Thu, 26 Mar 2020 00:00:50 GMT
2020-03-26T00:00:50.4994479Z == end clock drift check ==
2020-03-26T00:00:51.8601642Z 2020-03-26T00:00:51.8678372Z ##[error]Bash exited with code '1'.
2020-03-26T00:00:51.8694052Z ##[section]Finishing: Run build
2020-03-26T00:00:51.8748762Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70413/merge to s
2020-03-26T00:00:51.8753879Z Task : Get sources
2020-03-26T00:00:51.8754256Z Description : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-03-26T00:00:51.8754589Z Version : 1.0.0
2020-03-26T00:00:51.8754822Z Author : Microsoft
2020-03-26T00:00:51.8754822Z Author : Microsoft
2020-03-26T00:00:51.8755205Z Help : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
2020-03-26T00:00:51.8755627Z ==============================================================================
2020-03-26T00:00:52.2106293Z Cleaning any cached credential from repository: rust-lang/rust (GitHub)
2020-03-26T00:00:52.2161097Z ##[section]Finishing: Checkout rust-lang/rust@refs/pull/70413/merge to s
2020-03-26T00:00:52.2251353Z Cleaning up task key
2020-03-26T00:00:52.2252673Z Start cleaning up orphan processes.
2020-03-26T00:00:52.2429766Z Terminate orphan process: pid (3530) (python)
2020-03-26T00:00:52.3012376Z ##[section]Finishing: Finalize Job

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

varkor · 2020-03-26T15:21:30Z

@AminArria: could you rebase the three implementation-related commits into one? It's fine to have a separate commit for the tests. This just helps to keep the git history a little cleaner. After that, this all looks good, thanks!

- Added is_under_guard parameter to _match::is_useful and only add to the matrix if false - Added comments explaining behavior

AminArria · 2020-03-26T15:42:24Z

@varkor did the rebase

varkor · 2020-03-26T17:28:23Z

Thank you!

@bors r=Centril,Nadrieril,varkor rollup

bors · 2020-03-26T17:28:24Z

📌 Commit ae7fa30 has been approved by Centril,Nadrieril,varkor

…arning, r=Centril,Nadrieril,varkor Fix incorrect pattern warning "unreachable pattern" Fixesrust-lang#70372 Added `is_under_guard` parameter to `_match::is_useful` and only add it to the matrix if `false` Tested with: ```rust #![feature(or_patterns)] fn main() { match (3,42) { (a,_) | (_,a) if a > 10 => {println!("{}", a)} _ => () } match Some((3,42)) { Some((a, _)) | Some((_, a)) if a > 10 => {println!("{}", a)} _ => () } match Some((3,42)) { Some((a, _) | (_, a)) if a > 10 => {println!("{}", a)} _ => () } } ```

@ghost

Rollup of 6 pull requests Successful merges: - rust-lang#70384 (Refactor object file handling) - rust-lang#70397 (add 'fn write_u16s' to Memory) - rust-lang#70413 (Fix incorrect pattern warning "unreachable pattern") - rust-lang#70428 (`error_bad_item_kind`: add help text) - rust-lang#70429 (Clean up E0459 explanation) - rust-lang#70437 (Miri float->int casts: be explicit that this is saturating) Failed merges: r? @ghost

rust-highfive assigned estebank Mar 25, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 25, 2020

Centril reviewed Mar 25, 2020
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rust-highfive assigned varkor and unassigned estebank Mar 25, 2020

Centril added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. F-or_patterns `#![feature(or_patterns)]` and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 25, 2020

Centril reviewed Mar 26, 2020
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Centril added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Mar 26, 2020

Nadrieril approved these changes Mar 26, 2020
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AminArria added 2 commits March 26, 2020 12:34

Fix incorrect pattern warning "unreachable pattern"
5796e6e
- Added is_under_guard parameter to _match::is_useful and only add to the matrix if false - Added comments explaining behavior

Add tests based on issuerust-lang#70372comments
ae7fa30

AminArria force-pushed the match-pattern-incorrect-warning branch from e9539f0 to ae7fa30Compare March 26, 2020 15:36

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 Mar 26, 2020

Dylan-DPC-zz mentioned this pull request Mar 26, 2020
Rollup of 6 pull requests #70438
Closed

Dylan-DPC-zz mentioned this pull request Mar 26, 2020
Rollup of 6 pull requests #70441
Merged

bors merged commit c640b95 into rust-lang:masterMar 27, 2020

AminArria deleted the match-pattern-incorrect-warning branch March 27, 2020 04:13

Centril mentioned this pull request Mar 27, 2020
Tracking issue for RFC 2535, 2530, 2175, "Or patterns, i.e Foo(Bar(x) | Baz(x))" #54883
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Fix incorrect pattern warning "unreachable pattern" - #70413

Fix incorrect pattern warning "unreachable pattern"#70413
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