Add must_use annotations to Result::is_ok and is_err#59648

alex · 2019-04-02T22:10:50Z

Discussed in #59610

rust-highfive · 2019-04-02T22:10:53Z

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

Centril · 2019-04-02T23:47:19Z

rust-highfive · 2019-04-03T00:53:09Z

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:33bdd66e:start=1554246474995518721,finish=1554246550537942024,duration=75542423303
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
travis_time:start:test_assembly
Check compiletest suite=assembly mode=assembly (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:22:48] 
[01:22:48] running 9 tests
[01:22:48] iiiiiiiii
[01:22:48] 
[01:22:48]  finished in 0.150
[01:22:48] travis_fold:end:test_assembly

---
travis_time:start:test_debuginfo
Check compiletest suite=debuginfo mode=debuginfo-both (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:23:04] 
[01:23:04] running 121 tests
[01:23:29] .iiiii...i.....i..i...i..i.i.i..i.ii...i.....i..i....i..........iiii..........i...ii...i.......ii.i. 100/121
[01:23:34] i.i......iii.i.....ii
[01:23:34] 
[01:23:34]  finished in 29.946
[01:23:34] travis_fold:end:test_debuginfo

---
[01:42:57] ............................i.i.....................................iiii........ii.................. 500/998
[01:43:05] .................................................................................................... 600/998
[01:43:13] .................................................................................................... 700/998
[01:43:21] ....................iiii............................................................................ 800/998
[01:43:35] ..........................F......................................................................... 900/998
[01:43:43] failures:
[01:43:43] 
[01:43:43] ---- sync/mpsc/mod.rs - sync::mpsc::SyncSender<T>::try_send (line 989) stdout ----
[01:43:43] ---- sync/mpsc/mod.rs - sync::mpsc::SyncSender<T>::try_send (line 989) stdout ----
[01:43:43] error: unused return value of `std::result::Result::<T, E>::is_err` that must be used
[01:43:43]   --> sync/mpsc/mod.rs:1008:5
[01:43:43]    |
[01:43:43] 22 |     sync_sender2.try_send(3).is_err();
[01:43:43]    |
[01:43:43] note: lint level defined here
[01:43:43]   --> sync/mpsc/mod.rs:987:9
[01:43:43]    |
[01:43:43]    |
[01:43:43] 1  | #![deny(warnings)]
[01:43:43]    |         ^^^^^^^^
[01:43:43]    = note: #[deny(unused_must_use)] implied by #[deny(warnings)]
[01:43:43] error: aborting due to previous error
[01:43:43] 
[01:43:43] thread 'sync/mpsc/mod.rs - sync::mpsc::SyncSender<T>::try_send (line 989)' panicked at 'couldn't compile the test', src/librustdoc/test.rs:310:13
[01:43:43] note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
---
[01:43:43] 
[01:43:43] error: test failed, to rerun pass '--doc'
[01:43:43] 
[01:43:43] 
[01:43:43] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "test" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--features" "panic-unwind backtrace" "--manifest-path" "/checkout/src/libstd/Cargo.toml" "-p" "std" "--" "--quiet"
[01:43:43] 
[01:43:43] 
[01:43:43] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:43:43] Build completed unsuccessfully in 0:32:29
[01:43:43] Build completed unsuccessfully in 0:32:29
[01:43:43] Makefile:48: recipe for target 'check' failed
[01:43:43] make: *** [check] Error 1
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:195bab52
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Wed Apr  3 00:53:03 UTC 2019

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 @TimNN. (Feature Requests)

rust-highfive · 2019-04-03T02:46:20Z

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:016dcfaf:start=1554252980999365318,finish=1554253056044412847,duration=75045047529
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
travis_time:start:test_assembly
Check compiletest suite=assembly mode=assembly (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:24:24] 
[01:24:24] running 9 tests
[01:24:24] iiiiiiiii
[01:24:24] 
[01:24:24]  finished in 0.162
[01:24:24] travis_fold:end:test_assembly

---
travis_time:start:test_debuginfo
Check compiletest suite=debuginfo mode=debuginfo-both (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:24:41] 
[01:24:41] running 121 tests
[01:25:07] .iiiii...i.....i..i...i..i.i.i..i.ii...i.....i..i....i..........iiii..........i...ii...i.......ii.i. 100/121
[01:25:12] i.i......iii.i.....ii
[01:25:12] 
[01:25:12]  finished in 31.000
[01:25:12] travis_fold:end:test_debuginfo

---
[01:48:23] travis_fold:start:test_stage1-rustc_data_structures
travis_time:start:test_stage1-rustc_data_structures
Testing rustc_data_structures stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:48:23]    Compiling rustc_data_structures v0.0.0 (/checkout/src/librustc_data_structures)
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_ok` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1474:13
[01:48:28]      |
[01:48:28] 1474 |             OwningRef::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_ok();
[01:48:28]      |
[01:48:28]      = note: `-D unused-must-use` implied by `-D warnings`
[01:48:28] 
[01:48:28] 
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_err` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1484:13
[01:48:28]      |
[01:48:28] 1484 |             OwningRef::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err();
[01:48:28] 
[01:48:28] 
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_ok` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1871:13
[01:48:28]      |
[01:48:28] 1871 |             OwningRefMut::new(y).try_map_mut(|x| x.downcast_mut::<i32>().ok_or(())).is_ok();
[01:48:28] 
[01:48:28] 
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_err` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1881:13
[01:48:28]      |
[01:48:28] 1881 |             OwningRefMut::new(y).try_map_mut(|x| x.downcast_mut::<i32>().ok_or(())).is_err();
[01:48:28] 
[01:48:28] 
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_ok` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1891:13
[01:48:28]      |
[01:48:28] 1891 |             OwningRefMut::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_ok();
[01:48:28] 
[01:48:28] 
[01:48:28] error: unused return value of `std::result::Result::<T, E>::is_err` that must be used
[01:48:28]     --> src/librustc_data_structures/owning_ref/mod.rs:1901:13
[01:48:28]      |
[01:48:28] 1901 |             OwningRefMut::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err();
[01:48:28] 
[01:48:28] error: aborting due to 6 previous errors
[01:48:28] 
[01:48:28] error: Could not compile `rustc_data_structures`.
[01:48:28] error: Could not compile `rustc_data_structures`.
[01:48:28] 
[01:48:28] To learn more, run the command again with --verbose.
[01:48:28] 
[01:48:28] 
[01:48:28] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "test" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--features" "" "--manifest-path" "/checkout/src/rustc/Cargo.toml" "-p" "rustc_data_structures" "--" "--quiet"
[01:48:28] 
[01:48:28] 
[01:48:28] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:48:28] Build completed unsuccessfully in 0:36:15
[01:48:28] Build completed unsuccessfully in 0:36:15
[01:48:28] make: *** [check] Error 1
[01:48:28] Makefile:48: recipe for target 'check' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0ecd3c58
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Wed Apr  3 02:46:14 UTC 2019
---
travis_time:end:21cc9c05:start=1554259576147536937,finish=1554259576154532158,duration=6995221
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:1bd0e83d
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:1fd46d6b
travis_time:start:1fd46d6b
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:06915e62
$ dmesg | grep -i kill

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 @TimNN. (Feature Requests)

alex · 2019-04-03T02:48:03Z

This seems to have caught several cases in some tests, e.g. https://github.com/rust-lang/rust/blob/master/src/librustc_data_structures/owning_ref/mod.rs#L1474

I think that's missing an assert!(), does that sound right?

scottmcm · 2019-04-03T06:37:21Z

If this is worth it on is_err, wouldn't it also need to be on is_some and such as well?

(Or I wonder if it would make sense to have a special lint for unused is_*?)

alexcrichton · 2019-04-05T15:17:58Z

@alex want to fix the issues found on CI?

It seems reasonable to have similar treatment on Option, and I would prefer that we not get too overzealous and try to match all is_* functions automatically

alex · 2019-04-05T15:21:34Z

@alexcrichton Yes, I'd like to! I could use some feedback on the question I asked WRT these tests: https://github.com/rust-lang/rust/blob/master/src/librustc_data_structures/owning_ref/mod.rs#L1467-L1485

try_map1 and try_map2 look identical to me, except one calls is_ok and the other is_err and I'm honestly unclear on what either of them is trying to assert.

alexcrichton · 2019-04-05T15:37:11Z

I don't know myself (didn't write those tests) but it seems harmless to either throw in assert! or assert!(!...) depending on what works

alex · 2019-04-05T15:54:53Z

👍 will update to get these tests passing this evening.

rust-highfive · 2019-04-06T18:23:14Z

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:014eb62c:start=1554568903370964474,finish=1554568979359721164,duration=75988756690
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
travis_time:start:test_assembly
Check compiletest suite=assembly mode=assembly (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:15:30] 
[01:15:30] running 9 tests
[01:15:30] iiiiiiiii
[01:15:30] 
[01:15:30]  finished in 0.156
[01:15:30] travis_fold:end:test_assembly

---
travis_time:start:test_debuginfo
Check compiletest suite=debuginfo mode=debuginfo-both (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:15:47] 
[01:15:47] running 121 tests
[01:16:14] .iiiii...i.....i..i...i..i.i.i..i.ii...i.....i..i....i..........iiii..........i...ii...i.......ii.i. 100/121
[01:16:18] i.i......iii.i.....ii
[01:16:18] 
[01:16:18]  finished in 31.314
[01:16:18] travis_fold:end:test_debuginfo

---
[01:40:00]     Finished release [optimized] target(s) in 17.24s
[01:40:00]      Running build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc_data_structures-f644b6b7e75576ad
[01:40:00] 
[01:40:00] running 141 tests
[01:40:00] .........................................................F..........................F.F............. 100/141
[01:40:00] failures:
[01:40:00] 
[01:40:00] ---- owning_ref::tests::owning_ref::try_map2 stdout ----
[01:40:00] ---- owning_ref::tests::owning_ref::try_map2 stdout ----
[01:40:00] thread 'owning_ref::tests::owning_ref::try_map2' panicked at 'assertion failed: OwningRef::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err()', src/librustc_data_structures/owning_ref/mod.rs:1484:13
[01:40:00] 
[01:40:00] ---- owning_ref::tests::owning_ref_mut::try_map2 stdout ----
[01:40:00] ---- owning_ref::tests::owning_ref_mut::try_map2 stdout ----
[01:40:00] thread 'owning_ref::tests::owning_ref_mut::try_map2' panicked at 'assertion failed: OwningRefMut::new(y).try_map_mut(|x|
[01:40:00]                                      x.downcast_mut::<i32>().ok_or(())).is_err()', src/librustc_data_structures/owning_ref/mod.rs:1881:13
[01:40:00] ---- owning_ref::tests::owning_ref_mut::try_map4 stdout ----
[01:40:00] ---- owning_ref::tests::owning_ref_mut::try_map4 stdout ----
[01:40:00] thread 'owning_ref::tests::owning_ref_mut::try_map4' panicked at 'assertion failed: OwningRefMut::new(y).try_map(|x| x.downcast_ref::<i32>().ok_or(())).is_err()', src/librustc_data_structures/owning_ref/mod.rs:1901:13
[01:40:00] 
[01:40:00] failures:
[01:40:00]     owning_ref::tests::owning_ref::try_map2
[01:40:00]     owning_ref::tests::owning_ref_mut::try_map2
[01:40:00]     owning_ref::tests::owning_ref_mut::try_map2
[01:40:00]     owning_ref::tests::owning_ref_mut::try_map4
[01:40:00] 
[01:40:00] test result: FAILED. 138 passed; 3 failed; 0 ignored; 0 measured; 0 filtered out
[01:40:00] 
[01:40:00] error: test failed, to rerun pass '--lib'
[01:40:00] 
[01:40:00] 
[01:40:00] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "test" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--features" "" "--manifest-path" "/checkout/src/rustc/Cargo.toml" "-p" "rustc_data_structures" "--" "--quiet"
[01:40:00] 
[01:40:00] 
[01:40:00] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:40:00] Build completed unsuccessfully in 0:36:47
[01:40:00] Build completed unsuccessfully in 0:36:47
[01:40:00] make: *** [check] Error 1
[01:40:00] Makefile:48: recipe for target 'check' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:28a4aaa8
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Sat Apr  6 18:23:08 UTC 2019

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 @TimNN. (Feature Requests)

alexcrichton · 2019-04-08T14:58:55Z

@alex did you want to add similar treatment to is_some and is_none in this PR?

alex · 2019-04-08T15:03:09Z

If you'd prefer it as a part of this PR, I'm happy to.

alexcrichton · 2019-04-08T15:06:02Z

Yes since they're so similar in purpose let's go ahead and add them in this PR

rust-highfive · 2019-04-08T16:26:27Z

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:028a9697:start=1554736294062221224,finish=1554736296264206350,duration=2201985126
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
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$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
[01:09:26] .................................................................................................... 800/2961
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---
[01:14:34] failures:
[01:14:34] 
[01:14:34] ---- [run-pass] run-pass/issues/issue-18353.rs stdout ----
[01:14:34] normalized stderr:
[01:14:34] warning: unused return value of `std::option::Option::<T>::is_some` that must be used
[01:14:34]    |
[01:14:34] LL |     str.is_some();
[01:14:34]    |     ^^^^^^^^^^^^^^
[01:14:34]    |
[01:14:34]    |
[01:14:34]    = note: #[warn(unused_must_use)] on by default
[01:14:34] 
[01:14:34] 
[01:14:34] 
[01:14:34] 
[01:14:34] The actual stderr differed from the expected stderr.
[01:14:34] Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/issues/issue-18353/issue-18353.stderr
[01:14:34] To update references, rerun the tests and pass the `--bless` flag
[01:14:34] To only update this specific test, also pass `--test-args issues/issue-18353.rs`
[01:14:34] error: 1 errors occurred comparing output.
[01:14:34] status: exit code: 0
[01:14:34] status: exit code: 0
[01:14:34] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/run-pass/issues/issue-18353.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/issues/issue-18353/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/issues/issue-18353/auxiliary"
[01:14:34] ------------------------------------------
[01:14:34] 
[01:14:34] ------------------------------------------
[01:14:34] stderr:
[01:14:34] stderr:
[01:14:34] ------------------------------------------
[01:14:34] {"message":"unused return value of `std::option::Option::<T>::is_some` that must be used","code":{"code":"unused_must_use","explanation":null},"level":"warning","spans":[{"file_name":"/checkout/src/test/run-pass/issues/issue-18353.rs","byte_start":234,"byte_end":248,"line_start":14,"line_end":14,"column_start":5,"column_end":19,"is_primary":true,"text":[{"text":"    str.is_some();","highlight_start":5,"highlight_end":19}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"#[warn(unused_must_use)] on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null}],"rendered":"warning: unused return value of `std::option::Option::<T>::is_some` that must be used\n  --> /checkout/src/test/run-pass/issues/issue-18353.rs:14:5\n   |\nLL |     str.is_some();\n   |     ^^^^^^^^^^^^^^\n   |\n   = note: #[warn(unused_must_use)] on by default\n\n"}
[01:14:34] ------------------------------------------
[01:14:34] 
[01:14:34] thread '[run-pass] run-pass/issues/issue-18353.rs' panicked at 'explicit panic', src/tools/compiletest/src/runtest.rs:3425:9
[01:14:34] note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
---
[01:14:34] 
[01:14:34] thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:516:22
[01:14:34] 
[01:14:34] 
[01:14:34] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/run-pass" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "run-pass" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-6.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "6.0.0\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[01:14:34] 
[01:14:34] 
[01:14:34] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:14:34] Build completed unsuccessfully in 0:11:06
[01:14:34] Build completed unsuccessfully in 0:11:06
[01:14:34] make: *** [check] Error 1
[01:14:34] Makefile:48: recipe for target 'check' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:00f03225
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Mon Apr  8 16:26:21 UTC 2019
---
travis_time:end:1e3e21b4:start=1554740782698621896,finish=1554740782753960234,duration=55338338
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:09e11d99
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:164cc948
$ dmesg | grep -i kill

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 @TimNN. (Feature Requests)

alex · 2019-04-08T16:28:20Z

Another failing test, again I'm not sure I fully understand what this one is trying to test. I think let _ = ...; is the correct fix?

alexcrichton · 2019-04-09T14:18:03Z

@rfcbot fcp merge

rfcbot · 2019-04-09T14:18:05Z

Team member @alexcrichton has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

rfcbot · 2019-04-12T22:42:11Z

🔔 This is now entering its final comment period, as per the review above. 🔔

alexcrichton · 2019-04-15T14:34:45Z

@bors: r+

bors · 2019-04-15T14:34:46Z

📌 Commit ce5d694 has been approved by alexcrichton

RalfJung · 2019-04-15T15:09:36Z

src/libcore/option.rs

    /// ```
    ///
    /// [`Some`]: #variant.Some
+    #[must_use]


Might be a good idea to add a message here (must_use = "msg") explaining that this function has no side-effects, or so?

Agreed! Maybe with a pointer to unwrap or expect if people meant it to be an assertion?

Did this ever get resolved? If not someone should open a pr for it.

Nope, there's still no message. Can you open an issue or a PR?

I would but I honestly have no clue what to put for the message.

@czipperz Well, inspired by https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.collect, here's a proposal for the text:

Result::is_ok: if you intended to assert that this matches Ok(_), consider .unwrap() instead

Result::is_err: if you intended to assert that this matches Err(_), consider .unwrap_err() instead

Option::is_some: if you intended to assert that this matches Some(_), consider .unwrap() instead

Option::is_none: if you intended to assert that this matches None, consider .or_else(|| panic!("called `Option::unwrap()` on a `None` value")) instead

(That last one makes me think of https://internals.rust-lang.org/t/adding-option-expect-none/10481?u=scottmcm...)

I'll open a PR based on those messages tonight if someone else doesn't do it first.

bors · 2019-04-15T16:17:59Z

⌛ Testing commit ce5d694 with merge 04247b041cdc0a35151d9232d23ced24341bbb95...

Add must_use annotations to Result::is_ok and is_err Discussed in rust-lang#59610

Centril · 2019-04-15T16:24:14Z

@bors retry

Yielding in favor of r0llup this is included in.

@ghost

Rollup of 6 pull requests Successful merges: - #59648 (Add must_use annotations to Result::is_ok and is_err) - #59748 (Add summary and reference to Rust trademark guide) - #59779 (Uplift `get_def_path` from Clippy) - #59955 (bump stdsimd; make intra_doc_link_resolution_failure an error again; make lints more consistent) - #59978 (rustdoc: Remove default keyword from re-exported trait methods) - #59989 (Fix links to Atomic* in RELEASES.md) Failed merges: r? @ghost

Pkgsrc changes: * NetBSD/sparc64 disabling of "packed" removed ("packed" removed upstream) * Adapt src_libstd_build.rs patch, update sed'ing of .cargo-checksum.json Build verified on NetBSD 8.0/amd64. Upstream changes: Version 1.36.0 (2019-07-04) ========================== Language -------- - [Non-Lexical Lifetimes are now enabled on the 2015 edition.][59114] - [The order of traits in trait objects no longer affects the semantics of that object.][59445] e.g. `dyn Send + fmt::Debug` is now equivalent to `dyn fmt::Debug + Send`, where this was previously not the case. Libraries --------- - [`HashMap`'s implementation has been replaced with `hashbrown::HashMap` implem entation.][58623] - [`TryFromSliceError` now implements `From<Infallible>`.][60318] - [`mem::needs_drop` is now available as a const fn.][60364] - [`alloc::Layout::from_size_align_unchecked` is now available as a const fn.][6 0370] - [`String` now implements `BorrowMut<str>`.][60404] - [`io::Cursor` now implements `Default`.][60234] - [Both `NonNull::{dangling, cast}` are now const fns.][60244] - [The `alloc` crate is now stable.][59675] `alloc` allows you to use a subset of `std` (e.g. `Vec`, `Box`, `Arc`) in `#![no_std]` environments if the environment has access to heap memory allocation. - [`String` now implements `From<&String>`.][59825] - [You can now pass multiple arguments to the `dbg!` macro.][59826] `dbg!` will return a tuple of each argument when there is multiple arguments. - [`Result::{is_err, is_ok}` are now `#[must_use]` and will produce a warning if not used.][59648] Stabilized APIs --------------- - [`VecDeque::rotate_left`] - [`VecDeque::rotate_right`] - [`Iterator::copied`] - [`io::IoSlice`] - [`io::IoSliceMut`] - [`Read::read_vectored`] - [`Write::write_vectored`] - [`str::as_mut_ptr`] - [`mem::MaybeUninit`] - [`pointer::align_offset`] - [`future::Future`] - [`task::Context`] - [`task::RawWaker`] - [`task::RawWakerVTable`] - [`task::Waker`] - [`task::Poll`] Cargo ----- - [Cargo will now produce an error if you attempt to use the name of a required dependency as a feature.][cargo/6860] - [You can now pass the `--offline` flag to run cargo without accessing the netw ork.][cargo/6934] You can find further change's in [Cargo's 1.36.0 release notes][cargo-1-36-0]. Clippy ------ There have been numerous additions and fixes to clippy, see [Clippy's 1.36.0 rel ease notes][clippy-1-36-0] for more details. Misc ---- Compatibility Notes ------------------- - [`std::arch::x86::_rdtsc` returns `u64` instead of `i64`][stdsimd/559] - [`std::arch::x86_64::_mm_shuffle_ps` takes an `i32` instead of `u32` for `mask `][stdsimd/522] - With the stabilisation of `mem::MaybeUninit`, `mem::uninitialized` use is no longer recommended, and will be deprecated in 1.38.0. [60318]: rust-lang/rust#60318 [60364]: rust-lang/rust#60364 [60370]: rust-lang/rust#60370 [60404]: rust-lang/rust#60404 [60234]: rust-lang/rust#60234 [60244]: rust-lang/rust#60244 [58623]: rust-lang/rust#58623 [59648]: rust-lang/rust#59648 [59675]: rust-lang/rust#59675 [59825]: rust-lang/rust#59825 [59826]: rust-lang/rust#59826 [59445]: rust-lang/rust#59445 [59114]: rust-lang/rust#59114 [cargo/6860]: rust-lang/cargo#6860 [cargo/6934]: rust-lang/cargo#6934 [`VecDeque::rotate_left`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_left [`VecDeque::rotate_right`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_right [`Iterator::copied`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.copied [`io::IoSlice`]: https://doc.rust-lang.org/std/io/struct.IoSlice.html [`io::IoSliceMut`]: https://doc.rust-lang.org/std/io/struct.IoSliceMut.html [`Read::read_vectored`]: https://doc.rust-lang.org/std/io/trait.Read.html#method.read_vectored [`Write::write_vectored`]: https://doc.rust-lang.org/std/io/trait.Write.html#method.write_vectored [`str::as_mut_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_mut_ptr [`mem::MaybeUninit`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html [`pointer::align_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.align_offset [`future::Future`]: https://doc.rust-lang.org/std/future/trait.Future.html [`task::Context`]: https://doc.rust-lang.org/beta/std/task/struct.Context.html [`task::RawWaker`]: https://doc.rust-lang.org/beta/std/task/struct.RawWaker.html [`task::RawWakerVTable`]: https://doc.rust-lang.org/beta/std/task/struct.RawWakerVTable.html [`task::Waker`]: https://doc.rust-lang.org/beta/std/task/struct.Waker.html [`task::Poll`]: https://doc.rust-lang.org/beta/std/task/enum.Poll.html [clippy-1-36-0]: https://github.com/rust-lang/rust-clippy/blob/master/CHANGELOG.md#rust-136 [cargo-1-36-0]: https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-136-2019-07-04 [stdsimd/522]: rust-lang/stdarch#522 [stdsimd/559]: rust-lang/stdarch#559

rust-highfive assigned kennytm Apr 2, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Apr 2, 2019

rust-highfive assigned alexcrichton and unassigned kennytm Apr 2, 2019

alex force-pushed the must-use-result branch from 27843b9 to f2b2f78 Compare April 3, 2019 00:55

alex force-pushed the must-use-result branch from f2b2f78 to 2f40ca0 Compare April 6, 2019 16:40

alex force-pushed the must-use-result branch from 2f40ca0 to a572f7f Compare April 7, 2019 04:35

alex force-pushed the must-use-result branch from a572f7f to b20a7b8 Compare April 8, 2019 15:10

Add must_use annotations to Result::is_ok and is_err

ce5d694

alex force-pushed the must-use-result branch from b20a7b8 to ce5d694 Compare April 8, 2019 16:58

alexcrichton added the T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. label Apr 9, 2019

rfcbot added the proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. label Apr 9, 2019

rfcbot added the disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. label Apr 9, 2019

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Apr 12, 2019

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 15, 2019

RalfJung reviewed Apr 15, 2019

View reviewed changes

Centril added a commit to Centril/rust that referenced this pull request Apr 15, 2019

Rollup merge of rust-lang#59648 - alex:must-use-result, r=alexcrichton

92702c1

Add must_use annotations to Result::is_ok and is_err Discussed in rust-lang#59610

Centril mentioned this pull request Apr 15, 2019

Rollup of 6 pull requests #59991

Merged

bors merged commit ce5d694 into rust-lang:master Apr 15, 2019

alex deleted the must-use-result branch April 15, 2019 19:32

rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Apr 22, 2019

czipperz mentioned this pull request Jul 6, 2019

Add messages to Option's and Result's must_use annotation for is_* #62431

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