t.Errorf("r.WriteTo(errorWriterToTests[%d]) = _, %v, want _,%v", i, err, rw.expected)
		}
	}
}

func TestWriterReadFrom(t *testing.T) {
	ws := []func(io.Writer) io.Writer{
		func(w io.Writer) io.Writer { return onlyWriter{w} },
		func(w io.Writer) io.Writer { return w },
	}

	rs := []func(io.Reader) io.Reader{
		iotest.DataErrReader,
		func(r io.Reader) io.Reader { return r },
	}

pkg mime/quotedprintable, func NewWriter(io.Writer) *Writer
pkg mime/quotedprintable, method (*Reader) Read([]uint8) (int, error)
pkg mime/quotedprintable, method (*Writer) Close() error
pkg mime/quotedprintable, method (*Writer) Write([]uint8) (int, error)
pkg mime/quotedprintable, type Reader struct
pkg mime/quotedprintable, type Writer struct
pkg mime/quotedprintable, type Writer struct, Binary bool

pkg log/syslog (netbsd-arm64-cgo), method (*Writer) Emerg(string) error
pkg log/syslog (netbsd-arm64-cgo), method (*Writer) Err(string) error
pkg log/syslog (netbsd-arm64-cgo), method (*Writer) Info(string) error
pkg log/syslog (netbsd-arm64-cgo), method (*Writer) Notice(string) error
pkg log/syslog (netbsd-arm64-cgo), method (*Writer) Warning(string) error

	b := bytes.NewBuffer(nil)
	w := NewWriter(b)
	for i := 0; i < 5; i++ {
		_, err := w.Create("")
		if err != nil {
			t.Fatalf("Writer.Create failed: %s", err)
		}
	}
	if err := w.Close(); err != nil {
		t.Fatalf("Writer.Close failed: %s", err)
	}
	r, err := NewReader(bytes.NewReader(b.Bytes()), int64(b.Len()))
	if err != nil {
		t.Fatalf("NewReader failed: %s", err)
	}

	Read(p []byte) (n int, err error)
	Close() error
}

type Writer interface {
	Write(p []byte) (n int, err error)
	Close() error
}

// ReadWriter's methods are Read, Write, and Close.
type ReadWriter interface {
	Reader  // includes methods of Reader in ReadWriter's method set
	Writer  // includes methods of Writer in ReadWriter's method set
}
</pre>

<p>

	"path"
	"sort"
	"strings"
	"time"
)

// Writer provides sequential writing of a tar archive.
// [Writer.WriteHeader] begins a new file with the provided [Header],
// and then Writer can be treated as an io.Writer to supply that file's data.
type Writer struct {
	w    io.Writer
	pad  int64      // Amount of padding to write after current file entry
	curr fileWriter // Writer for current file entry

func TestZip64DirectoryOffset(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping in short mode")
	}
	t.Parallel()
	const filename = "huge.txt"
	gen := func(wantOff uint64) func(*Writer) {
		return func(w *Writer) {
			w.testHookCloseSizeOffset = func(size, off uint64) {
				if off != wantOff {
					t.Errorf("central directory offset = %d (%x); want %d", off, off, wantOff)
				}
			}

	}
	if abs < 0 {
		return 0, errors.New("bytes.Reader.Seek: negative position")
	}
	r.i = abs
	return abs, nil
}

// WriteTo implements the [io.WriterTo] interface.
func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
	r.prevRune = -1
	if r.i >= int64(len(r.s)) {
		return 0, nil
	}
	b := r.s[r.i:]
	m, err := w.Write(b)
	if m > len(b) {
		panic("bytes.Reader.WriteTo: invalid Write count")
	}

pkg go/token, method (*File) LineStart(int) Pos
pkg io, type StringWriter interface { WriteString }
pkg io, type StringWriter interface, WriteString(string) (int, error)
pkg log, method (*Logger) Writer() io.Writer
pkg math/bits, func Add(uint, uint, uint) (uint, uint)
pkg math/bits, func Add32(uint32, uint32, uint32) (uint32, uint32)
pkg math/bits, func Add64(uint64, uint64, uint64) (uint64, uint64)

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))
	withOut.n, withOut.err = io.Copy(discard, justReader{NewReader(nil)})