x/tools/gopls: Diagnostics: incorrect end column on errors containing "-" (wrong cutset in TypeErrorEndPos)

[oversoul]

Go version

go1.23.1

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/ae/.cache/go-build'
GOENV='/home/ae/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/ae/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/ae/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/go/'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.1'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/ae/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/mnt/ddrive/Codes/golang/memo/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build4126319014=/tmp/go-build -gno-record-gcc-switches'

What did you do?

Take this example

import (
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
)

type (
	Token struct {
		Id     primitive.ObjectID `bson:"_id,omitempty"`
		Name   string             `bson:"name"`
		Token  string             `bson:"token"`
		UserId primitive.ObjectID `bson:"user_id"`
	}
        // ...
)

What did you see happen?

On editor (sublime, neovim), because of the unused import "go.mongodb.org/mongo-driver/bson"
it highlights only until the -.
Using gopls command
gopls check api/auth/models.go
the output is:

api/auth/models.go:4:2-23: "go.mongodb.org/mongo-driver/bson" imported and not used

23 here is wrong. should be 36.

What did you expect to see?

api/auth/models.go:4:2-36: "go.mongodb.org/mongo-driver/bson" imported and not used

After some research, The issue is in TypeErrorEndPos

tools/gopls/internal/analysisinternal/analysis.go Line 29

if width := bytes.IndexAny(src[offset:], " \n,():;[]+-*"); width > 0 {

after removing the hyphen, it works as expected. I did run the tests after the change but no tests seems to break.

[adonovan]

Thanks for the thorough investigation.

The inclusion of -+* in TypeErrorEndPos logic was added in https://go.dev/cl/222237; neither the CL description nor any of the test cases reveal why. It would be interesting to instrument go/types to record whenever it produces an error containing one of these symbols, and run its tests (and run it over the standard library) to see what comes up.

[gabyhelp]

Related Issues and Documentation

• x/tools/gopls: broken import error with v0.13.0 #61687 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[gopherbot]

Change https://go.dev/cl/625916 mentions this issue: internal/analysisinternal: avoid sub-token spans in TypeErrorEndPos