// regardless of the presence of a WriteTo method.
func TestReaderCopyNothing(t *testing.T) {
	type nErr struct {
		n   int64
		err error
	}
	type justReader struct {
		io.Reader
	}
	type justWriter struct {
		io.Writer
	}
	discard := justWriter{io.Discard} // hide ReadFrom

	var with, withOut nErr
	with.n, with.err = io.Copy(discard, NewReader(nil))

import (
	"archive/tar"
	"bytes"
	"fmt"
	"io"
	"log"
	"os"
)

func Example_minimal() {
	// Create and add some files to the archive.
	var buf bytes.Buffer
	tw := tar.NewWriter(&buf)
	var files = []struct {
		Name, Body string
	}{
		{"readme.txt", "This archive contains some text files."},
		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
		{"todo.txt", "Get animal handling license."},
	}

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package asm

import (
	"cmd/asm/internal/lex"
	"strings"
	"testing"
)

type badInstTest struct {
	input, error string
}

func TestAMD64BadInstParser(t *testing.T) {
	testBadInstParser(t, "amd64", []badInstTest{
		// Test AVX512 suffixes.
		{"VADDPD.A X0, X1, X2", `unknown suffix "A"`},

	Importpath = flag.String("p", obj.UnlinkablePkg, "set expected package import to path")
	Spectre    = flag.String("spectre", "", "enable spectre mitigations in `list` (all, ret)")
)

var DebugFlags struct {
	MayMoreStack string `help:"call named function before all stack growth checks"`
	PCTab        string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
}

var (

// io.ByteScanner, and io.RuneScanner interfaces by reading from
// a byte slice.
// Unlike a [Buffer], a Reader is read-only and supports seeking.
// The zero value for Reader operates like a Reader of an empty slice.
type Reader struct {
	s        []byte
	i        int64 // current reading index
	prevRune int   // index of previous rune; or < 0
}

// Len returns the number of bytes of the unread portion of the
// slice.

func TakesFunc(f func(dontWantName int) int)

type Codec struct {
	Func func(x int, y int) (z int)
}

type SI struct {
	I int
}

var SIVal = SI{}
var SIPtr = &SI{}
var SIPtr2 *SI

type T struct {
	common
}

type B struct {
	common
}

type common struct {
	i int
}

type TPtrUnexported struct {
	*common
}

type TPtrExported struct {

		// say "pkg syscall (darwin-amd64), type RawSockaddrInet6 struct" is missing.
		// See https://go.dev/issue/4303.
		{
			name: "contexts reconverging after api/next/* update",
			features: []string{
				"A",
				"pkg syscall, type RawSockaddrInet6 struct",
			},
			required: []string{
				"A",
				"pkg syscall (darwin-amd64), type RawSockaddrInet6 struct", // api/go1.n.txt

// Copyright 2018 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 a

// typedef struct S ST;
// struct S { int f; };
import "C"

func F2(p *C.ST) {
	p.f = 1

	if len(s) == 0 {
		return res
	}
	for _, o := range strings.Split(s, ",") {
		res = append(res, lex.Tokenize(o))
	}
	return res
}

func TestErroneous(t *testing.T) {

	type errtest struct {
		pseudo   string
		operands string
		expected string
	}

	nonRuntimeTests := []errtest{
		{"TEXT", "", "expect two or three operands for TEXT"},
		{"TEXT", "%", "expect two or three operands for TEXT"},

		testCall()
	case "Callback":
		testCallback()
	}
	println("OK")
}

func fatal(f string, args ...any) {
	fmt.Fprintln(os.Stderr, fmt.Sprintf(f, args...))
	os.Exit(1)
}

type GoCallback struct{}

func (p *GoCallback) Run() string {
	return "GoCallback.Run"
}

func testCall() {
	c := NewCaller()
	cb := NewCallback()

	c.SetCallback(cb)
	s := c.Call()
	if s != "Callback::run" {