x/tools/go/analysis/unitchecker,slices: TestVetStdlib failing due to vet errors in panic tests

[bcmills]

Go version

8db1310

Output of go env in your module/workspace:

linux-arm64-longtest at 8db131082d08e497fd8e9383d0ff7715e1bef478 building tools at ba8672b53f4b6840528df6fd534cb16f65278711

:: Running /tmp/workdir/go/bin/go with args ["/tmp/workdir/go/bin/go" "test" "-timeout=50m0s" "./..."] and env ["HOSTNAME=fc37d78d0c48" "HOME=/root" "SHLVL=0" "DEBIAN_FRONTEND=noninteractive" "USER=root" "GO_STAGE0_NET_DELAY=0s" "GO_STAGE0_DL_DELAY=200ms" "WORKDIR=/tmp/workdir" "GOROOT_BOOTSTRAP=/tmp/workdir/go1.4" "GO_BUILDER_NAME=linux-arm64-longtest" "GO_TEST_SHORT=0" "GO_TEST_TIMEOUT_SCALE=5" "GOROOT=/tmp/workdir/go" "GOPATH=/tmp/workdir/gopath" "GOPROXY=http://gk3-services-nap-jetxd907-8f582974-hv4r.c.symbolic-datum-552.internal:30157" "TMPDIR=/tmp/workdir/tmp" "GOCACHE=/tmp/workdir/gocache" "GOPLSCACHE=/tmp/workdir/goplscache" "PATH=/tmp/workdir/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" "PWD=/tmp/workdir/gopath/src/golang.org/x/tools"] in dir /tmp/workdir/gopath/src/golang.org/x/tools

What did you do?

https://build.golang.org/log/2ee364aaab909e8dcc3be5bd1c45c1aa12dc8151

What did you see happen?

--- FAIL: TestVetStdlib (39.88s)
    vet_std_test.go:99: go vet std failed (exit status 1):
        # slices_test
        # [slices_test]
        /tmp/workdir/go/src/slices/slices_test.go:560:29: result of slices.Insert call not used
        /tmp/workdir/go/src/slices/slices_test.go:687:29: result of slices.Delete call not used
        /tmp/workdir/go/src/slices/slices_test.go:909:49: result of slices.Grow call not used
        /tmp/workdir/go/src/slices/slices_test.go:912:49: result of slices.Grow call not used
        /tmp/workdir/go/src/slices/slices_test.go:924:7: result of slices.Grow call not used
        /tmp/workdir/go/src/slices/slices_test.go:1040:30: result of slices.Replace call not used
FAIL
FAIL	golang.org/x/tools/go/analysis/unitchecker	48.138s

What did you expect to see?

All tests passing. (I believe this can be fixed by explicitly assigning to _ in the panic tests in slices_test.go.)

[adonovan]

Sorry, I did it again: I forgot that any change to the behavior of vet needs more thorough rollout. Will fix presently.

[gopherbot]

Change https://go.dev/cl/554196 mentions this issue: slices: explicitly discard results of some functions

[bcmills]

Fixed in https://go.dev/cl/554196.

[dmitshur]

@gopherbot Please backport to Go 1.21. This is a test-only fix that'll fix longtest builders.

[gopherbot]

Backport issue(s) opened: #65023 (for 1.21).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.

[gopherbot]

Change https://go.dev/cl/554756 mentions this issue: [release-branch.go1.21] slices: explicitly discard results of some functions