Golang x/tools/gopls/internal/analysis/modernize: produces invalid go code

gopls version

Build info
----------
golang.org/x/tools/gopls v0.18.1
    golang.org/x/tools/gopls@v0.18.1 h1:2xJBNzdImS5u/kV/ZzqDLSvlBSeZX+pWY9uKVP7Pask=
    github.com/BurntSushi/toml@v1.4.1-0.20240526193622-a339e1f7089c h1:pxW6RcqyfI9/kWtOwnv/G+AzdKuy2ZrqINhenH4HyNs=
    github.com/google/go-cmp@v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
    golang.org/x/exp/typeparams@v0.0.0-20241210194714-1829a127f884 h1:1xaZTydL5Gsg78QharTwKfA9FY9CZ1VQj6D/AZEvHR0=
    golang.org/x/mod@v0.23.0 h1:Zb7khfcRGKk+kqfxFaP5tZqCnDZMjC5VtUBs87Hr6QM=
    golang.org/x/sync@v0.11.0 h1:GGz8+XQP4FvTTrjZPzNKTMFtSXH80RAzG+5ghFPgK9w=
    golang.org/x/telemetry@v0.0.0-20241220003058-cc96b6e0d3d9 h1:L2k9GUV2TpQKVRGMjN94qfUMgUwOFimSQ6gipyJIjKw=
    golang.org/x/text@v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
    golang.org/x/tools@v0.30.1-0.20250221230316-5055f70f240c h1:Ja/5gV5a9Vvho3p2NC/T2TtxhHjrWS/2DvCKMvA0a+Y=
    golang.org/x/vuln@v1.1.3 h1:NPGnvPOTgnjBc9HTaUx+nj+EaUYxl5SJOWqaDYGaFYw=
    honnef.co/go/tools@v0.5.1 h1:4bH5o3b5ZULQ4UrBmP+63W9r7qIkqJClEA9ko5YKx+I=
    mvdan.cc/gofumpt@v0.7.0 h1:bg91ttqXmi9y2xawvkuMXyvAA/1ZGJqYAEGjXuP0JXU=
    mvdan.cc/xurls/v2@v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
go: go1.24.1

But doesn't really apply as I run modernize, manually:

$ modernize -V=full
/Users/lukasmalkmus/Code/Go/bin/modernize version devel comments-go-here buildID=2d82ded0e54f6bc5a49542ce20abf2cf16d5428f6408d508e92f41dd3f3e8e80

go env

Had to omit some values for privacy reasons

AR='ar'
CC='cc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='c++'
GCCGO='gccgo'
GO111MODULE=''
GOARCH='arm64'
GOARM64='v8.0'
GOAUTH='netrc'
GOBIN='/Users/lukasmalkmus/Code/Go/bin'
GOCACHE='/Users/lukasmalkmus/Library/Caches/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/Users/lukasmalkmus/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/cf/h57rh51s09l17jdrvlhmbsgr0000gn/T/go-build2509044316=/tmp/go-build -gno-record-gcc-switches -fno-common'
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/lukasmalkmus/Code/Go/pkg/mod'
GOOS='darwin'
GOPATH='/Users/lukasmalkmus/Code/Go'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/homebrew/Cellar/go/1.25.1/libexec'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/lukasmalkmus/Library/Application Support/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/homebrew/Cellar/go/1.25.1/libexec/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.25.1'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

I ran modernize -fix on the following Go 1.25 code:

package fail

import "sync"

type T struct {
    wg sync.WaitGroup
}

func (t *T) f() {
    t.wg.Add(1)
    go func() {
        defer t.wg.Done()
    }()
}

What did you see happen?

The resulting code is invalid:

package fail

import "sync"

type T struct {
    wg sync.WaitGroup
}

func (t *T) f() {
    &{t wg}.Go(func() {
    })
}

What did you expect to see?

Valid Go 1.25 code that uses sync.WaitGroup.Go:

package fail

import "sync"

type T struct {
    wg sync.WaitGroup
}

func (t *T) f() {
    t.wg.Go(func() {
    })
}

Editor and settings

No response

Logs

No response

Comment From: adonovan

Dup of #74708, now fixed.