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
	// the flags available during main flag processing.
	for i, arg := range args {
		if arg == "-vettool" || arg == "--vettool" {
			if i+1 >= len(args) {
				log.Fatalf("%s requires a filename", arg)
			}

}

type moduleErrorNoMethods ModuleError

// UnmarshalJSON accepts both {"Err":"text"} and "text",
// so that the output of go mod download -json can still
// be unmarshaled into a ModulePublic during -reuse processing.
func (e *ModuleError) UnmarshalJSON(data []byte) error {
	if len(data) > 0 && data[0] == '"' {
		return json.Unmarshal(data, &e.Err)
	}
	return json.Unmarshal(data, (*moduleErrorNoMethods)(e))
}

//
//	var do func(ir.Node) bool
//	do = func(x ir.Node) bool {
//		... processing BEFORE visiting children ...
//		if ... should visit children ... {
//			ir.DoChildren(x, do)
//		}
//		... processing AFTER visiting children ...
//		return false
//	}
//	do(root)
//
// The Visit function illustrates a further simplification of the pattern,
// only processing before visiting children and never stopping:
//

See also: go fmt, go fix.
	`,
}

func runVet(ctx context.Context, cmd *base.Command, args []string) {
	vetFlags, pkgArgs := vetFlags(args)
	modload.InitWorkfile() // The vet command does custom flag processing; initialize workspaces after that.

	if cfg.DebugTrace != "" {
		var close func() error
		var err error
		ctx, close, err = trace.Start(ctx, cfg.DebugTrace)
		if err != nil {

// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package cmdflag handles flag processing common to several go tools.
package cmdflag

import (
	"errors"
	"flag"
	"fmt"
	"strings"
)

// The flag handling part of go commands such as test is large and distracting.

func (in *Input) macroName() string {
	// We use the Stack's input method; no macro processing at this stage.
	tok := in.Stack.Next()
	if tok != scanner.Ident {
		in.expectText("expected identifier after # directive")
	}
	// Name is alphanumeric by definition.
	return in.Stack.Text()
}

// #define processing.
func (in *Input) define() {
	name := in.macroName()
	args, tokens := in.macroDefinition(name)

	noders := make([]*noder, len(filenames))
	for i := range noders {
		p := noder{
			err: make(chan syntax.Error),
		}
		noders[i] = &p
	}

	// Move the entire syntax processing logic into a separate goroutine to avoid blocking on the "sem".
	go func() {
		for i, filename := range filenames {
			filename := filename
			p := noders[i]
			sem <- struct{}{}
			go func() {

	for _, b := range f.Blocks {
		b.FlagsLiveAtEnd = end[b.ID] != nil
	}

	// Remove any now-dead values.
	// The number of values to remove is likely small,
	// and removing them requires processing all values in a block,
	// so minimize the number of blocks that we touch.

	// Shrink remove to contain only dead values, and clobber those dead values.
	for i := 0; i < len(remove); i++ {
		v := remove[i]

	case *ast.Expr:
		switch (*x).(type) {
		case *ast.SelectorExpr:
			f.saveRef(x, context)
		}
	case *ast.CallExpr:
		f.saveCall(x, context)
	}
}

// Save references to C.xxx for later processing.
func (f *File) saveRef(n *ast.Expr, context astContext) {
	sel := (*n).(*ast.SelectorExpr)
	// For now, assume that the only instance of capital C is when
	// used as the imported package identifier.

//     before moving on to the next test.
//  2. If a source line number is specified, set that in the parser
//     before executing the test.  i.e., execute the split as if it
//     processing that source line.
func TestGenerateCommandShorthand(t *testing.T) {
	dir := filepath.Join(testenv.GOROOT(t), "src", "sys")
	g := &Generator{
		r:        nil, // Unused here.
		path:     filepath.Join(dir, "proc.go"),