// to build the test in a way that supports the use of the flag.

	cf.StringVar(&testBench, "bench", "", "")
	cf.Bool("benchmem", false, "")
	cf.String("benchtime", "", "")
	cf.StringVar(&testBlockProfile, "blockprofile", "", "")
	cf.String("blockprofilerate", "", "")
	cf.Int("count", 0, "")
	cf.String("cpu", "", "")
	cf.StringVar(&testCPUProfile, "cpuprofile", "", "")
	cf.BoolVar(&testFailFast, "failfast", false, "")

// and 'go mod' subcommands.
func AddModCommonFlags(flags *flag.FlagSet) {
	flags.BoolVar(&cfg.ModCacheRW, "modcacherw", false, "")
	flags.StringVar(&cfg.ModFile, "modfile", "", "")
	flags.StringVar(&fsys.OverlayFile, "overlay", "", "")
}

func ChdirFlag(s string) error {
	// main handles -C by removing it from the command line.
	// If we see one during flag parsing, that's an error.

// implementation. It is also used by tests.
//
// The default behavior (vetTool=="") runs 'go tool vet'.
var vetTool string // -vettool

func init() {
	work.AddBuildFlags(CmdVet, work.DefaultBuildFlags)
	CmdVet.Flag.StringVar(&vetTool, "vettool", "", "")
}

func parseVettoolFlag(args []string) {
	// Extract -vettool by ad hoc flag processing:
	// its value is needed even before we can declare

var vendorO string // if set, overrides the default output directory

func init() {
	cmdVendor.Flag.BoolVar(&cfg.BuildV, "v", false, "")
	cmdVendor.Flag.BoolVar(&vendorE, "e", false, "")
	cmdVendor.Flag.StringVar(&vendorO, "o", "", "")
	base.AddChdirFlag(&cmdVendor.Flag)
	base.AddModCommonFlags(&cmdVendor.Flag)
}

func runVendor(ctx context.Context, cmd *base.Command, args []string) {
	modload.InitWorkfile()

		// consistency.
		cmd.Flag.StringVar(&fsys.OverlayFile, "overlay", "", "")
	}
	cmd.Flag.StringVar(&cfg.BuildContext.InstallSuffix, "installsuffix", "", "")
	cmd.Flag.Var(&load.BuildLdflags, "ldflags", "")
	cmd.Flag.BoolVar(&cfg.BuildLinkshared, "linkshared", false, "")
	cmd.Flag.StringVar(&cfg.BuildPGO, "pgo", "auto", "")
	cmd.Flag.StringVar(&cfg.BuildPkgdir, "pkgdir", "", "")

	var goexperiment, gotypesalias string
	flags := flag.NewFlagSet("", flag.PanicOnError)
	flags.StringVar(&conf.GoVersion, "lang", "", "")
	flags.StringVar(&goexperiment, "goexperiment", "", "")
	flags.BoolVar(&conf.FakeImportC, "fakeImportC", false, "")
	flags.StringVar(&gotypesalias, "gotypesalias", "", "")
	if err := parseFlags(srcs[0], flags); err != nil {
		t.Fatal(err)
	}

// do is the workhorse, broken out of main to make testing easier.
func do(writer io.Writer, flagSet *flag.FlagSet, args []string) (err error) {
	flagSet.Usage = usage
	unexported = false
	matchCase = false
	flagSet.StringVar(&chdir, "C", "", "change to `dir` before running command")
	flagSet.BoolVar(&unexported, "u", false, "show unexported symbols as well as exported")

var vendorO string // if set, overrides the default output directory

func init() {
	cmdVendor.Flag.BoolVar(&cfg.BuildV, "v", false, "")
	cmdVendor.Flag.BoolVar(&vendorE, "e", false, "")
	cmdVendor.Flag.StringVar(&vendorO, "o", "", "")
	base.AddChdirFlag(&cmdVendor.Flag)
	base.AddModCommonFlags(&cmdVendor.Flag)
}

func runVendor(ctx context.Context, cmd *base.Command, args []string) {
	modload.InitWorkfile()

	generateSkipRE   *regexp.Regexp // compiled expression for -skip
)

func init() {
	work.AddBuildFlags(CmdGenerate, work.DefaultBuildFlags)
	CmdGenerate.Flag.StringVar(&generateRunFlag, "run", "", "")
	CmdGenerate.Flag.StringVar(&generateSkipFlag, "skip", "", "")
}

func runGenerate(ctx context.Context, cmd *base.Command, args []string) {
	modload.InitWorkfile()

	if generateRunFlag != "" {

	flag.BoolVar(&t.race, "race", false, "run in race builder mode (different set of tests)")
	flag.BoolVar(&t.compileOnly, "compile-only", false, "compile tests, but don't run them")
	flag.StringVar(&t.banner, "banner", "##### ", "banner prefix; blank means no section banners")
	flag.StringVar(&t.runRxStr, "run", "",
		"run only those tests matching the regular expression; empty means to run all. "+
			"Special exception: if the string begins with '!', the match is inverted.")