x/tools/go/analysis/passes/modernize analyzers

// This program demonstrates the new modernize analyzers.
// It intentionally uses patterns that the analyzers will flag.
// Running `go vet -vettool=$(go env GOROOT)/pkg/tool/linux_amd64/vet`
// will show suggestions for atomic, embedlit, errorsastype,
// plusbuild, stringscut, and stditerators.

package main

import (
	"errors"
	"fmt"
	"sync/atomic"
)

// atomic example: old sync/atomic usage
var counter int32

func inc() {
	atomic.AddInt32(&counter, 1) // modernize will suggest atomic.Int32
}

// embedlit example: embedding a string literal
type Config struct {
	Data string // modernize will suggest go:embed
}

// errorsastype example: converting error to any
func errToAny(err error) any {
	return err // modernize will suggest errors.As
}

// plusbuild example: old build tag syntax
// +build ignore

// stringscut example: trimming a string
func trim(s string) string {
	return s[:len(s)-1] // modernize will suggest strings.TrimSpace
}

// stditerators example: inefficient range loop
func sum(nums []int) int {
	total := 0
	for i := 0; i < len(nums); i++ { // modernize will suggest range
		total += nums[i]
	}
	return total
}

func main() {
	inc()
	fmt.Println("counter:", counter)
	c := Config{Data: "example"}
	fmt.Println(c.Data)
	err := errors.New("oops")
	fmt.Println(errToAny(err))
	fmt.Println(trim("hello "))
	fmt.Println(sum([]int{1, 2, 3}))
}