unused: false positive: private embedded marker

[Antonboom]

Hello!

$ golangci-lint version   
golangci-lint has version 1.48.0 built from 2d8fea81 on 2022-08-04T18:44:38Z

# .golangci.yml
linters:
  disable-all: true
  enable:
    - unused

// internal/events/events.go
package events

type Event interface {
	eventMarker()
}

type event struct{}         //
func (*event) eventMarker() {}

type SomeEvent struct {
	event
	ID string
}

// main.go
package main

import (
	"fmt"
	
	"example/internal/events"
)

func main() {
	var ev events.Event = &events.SomeEvent{ID: "123"}
	fmt.Println(ev)
}

$ golangci-lint run  ./...  
internal/events/events.go:11:2: field `event` is unused (unused)
        event
        ^
internal/events/events.go:8:15: func `(*event).eventMarker` is unused (unused)
func (*event) eventMarker() {}
              ^
internal/events/events.go:7:6: type `event` is unused (unused)
type event struct{}         //
     ^

go env

▶ go env                  
GO111MODULE="on"
GOARCH="arm64"
GOBIN="/Users/anthony/golang_workspace/bin"
GOCACHE="/Users/anthony/Library/Caches/go-build"
GOENV="/Users/anthony/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/anthony/golang_workspace/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/anthony/golang_workspace"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_arm64"
GOVCS=""
GOVERSION="go1.18.2"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/private/tmp/example/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/6t/v80c8sfs5zqf38b2yhzq592h0000gn/T/go-build1593840402=/tmp/go-build -gno-record-gcc-switches -fno-common"

[Antonboom]

issue1312.zip

[dominikh]

A simple workaround for now is to include var _ Event = (*SomeEvent)(nil) in your events package.