path instead of "vendor". The go command can only use a vendor directory
named "vendor" within the module root directory, so this flag is
primarily useful for other tools.

See https://golang.org/ref/mod#go-mod-vendor for more about 'go mod vendor'.
	`,
	Run: runVendor,
}

var vendorE bool   // if true, report errors but proceed anyway
var vendorO string // if set, overrides the default output directory

func init() {

		sh.ShowCmd("", "cp %s %s", src, dst)
		if cfg.BuildN {
			return nil
		}
	}

	sf, err := os.Open(src)
	if err != nil {
		return err
	}
	defer sf.Close()

	// Be careful about removing/overwriting dst.
	// Do not remove/overwrite if dst exists and is a directory
	// or a non-empty non-object file.
	if fi, err := os.Stat(dst); err == nil {
		if fi.IsDir() {

	// map from value ID to known non-nil version of that value ID
	// (in the current dominator path being walked). This slice is updated by
	// walkStates to maintain the known non-nil values.
	// If there is extrinsic information about non-nil-ness, this map
	// points a value to itself. If a value is known non-nil because we
	// already did a nil check on it, it points to the nil check operation.
	nonNilValues := f.Cache.allocValueSlice(f.NumValues())

			`func internalFunc(a int) bool`,    // No internal functions.
			`Comment about exported constant`,  // No comment for single constant.
			`Comment about exported variable`,  // No comment for single variable.
			`Comment about block of constants`, // No comment for constant block.
			`Comment about block of variables`, // No comment for variable block.

useful on systems that do not preserve the module cache.

The -x flag causes download to print the commands download executes.

See https://golang.org/ref/mod#go-mod-download for more about 'go mod download'.

See https://golang.org/ref/mod#version-queries for more about version queries.
	`,
}

var (
	downloadJSON  = cmdDownload.Flag.Bool("json", false, "")
	downloadReuse = cmdDownload.Flag.String("reuse", "", "")
)

func init() {

// by just combining constant folding and constant propagation and dead code
// elimination separately.

// Three level lattice holds compile time knowledge about SSA value
const (
	top      int8 = iota // undefined
	constant             // constant
	bottom               // not a constant
)

type lattice struct {
	tag int8   // lattice type
	val *Value // constant value

new inputs are found that provide the same coverage. These files are
distinct from those stored in testdata directory; clean does not remove
those files.

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.
	`,
}

var (
	cleanI         bool // clean -i flag
	cleanR         bool // clean -r flag
	cleanCache     bool // clean -cache flag

	// The git protocol sends all known refs and ls-remote filters them on the client side,
	// so we might as well record both heads and tags in one shot.
	// Most of the time we only care about tags but sometimes we care about heads too.
	out, err := Run(ctx, r.dir, "git", "tag", "-l")
	if err != nil {
		return
	}

	for _, line := range strings.Split(string(out), "\n") {
		if line != "" {

			// in time.
			//
			// We do this only if the current version is a pseudo-version: if the
			// version is tagged, the author of the dependency module has given us
			// explicit information about their intended precedence of this version
			// relative to other versions, and we shouldn't contradict that
			// information. (For example, v1.0.1 might be a backport of a fix already

	// We must do this check prior to calling pp.Flush.
	// If there are any oversized stack frames,
	// the assembler may emit inscrutable complaints about invalid instructions.
	if pp.Text.To.Offset >= maxStackSize {
		largeStackFramesMu.Lock()
		locals := f.Frontend().(*ssafn).stksize