{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
		{seek: io.SeekStart, n: 5, want: "01234"},
		{seek: io.SeekCurrent, n: 5, want: "56789"},
		{seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
	}

	for i, tt := range tests {
		pos, err := r.Seek(tt.off, tt.seek)
		if err == nil && tt.seekerr != "" {
			t.Errorf("%d. want seek error %q", i, tt.seekerr)
			continue
		}

	return nil
}

// Seek implements the [io.Seeker] interface.
func (r *Reader) Seek(offset int64, whence int) (int64, error) {
	r.prevRune = -1
	var abs int64
	switch whence {
	case io.SeekStart:
		abs = offset
	case io.SeekCurrent:
		abs = r.i + offset
	case io.SeekEnd:
		abs = int64(len(r.s)) + offset
	default:
		return 0, errors.New("bytes.Reader.Seek: invalid whence")
	}
	if abs < 0 {

		// io.Seeker, but calling Seek always returns an error and performs
		// no action. Thus, we try an innocent seek to the current position
		// to see if Seek is really supported.
		pos1, err := sr.Seek(0, io.SeekCurrent)
		if pos1 >= 0 && err == nil {
			// Seek seems supported, so perform the real Seek.
			pos2, err := sr.Seek(n-1, io.SeekCurrent)
			if pos2 < 0 || err != nil {
				return err

	default:
		return n, nil
	}
}

func (sw *sparseFileWriter) ReadFrom(r io.Reader) (n int64, err error) {
	rs, ok := r.(io.ReadSeeker)
	if ok {
		if _, err := rs.Seek(0, io.SeekCurrent); err != nil {
			ok = false // Not all io.Seeker can really seek
		}
	}
	if !ok {
		return io.Copy(struct{ io.Writer }{sw}, r)
	}

	var readLastByte bool
	pos0 := sw.pos

	}
	if _, err := buf.Peek(1); err != io.EOF {
		t.Fatalf("want EOF got %v", err)
	}

	// Test for issue 3022, not exposing a reader's error on a successful Peek.
	buf = NewReaderSize(dataAndEOFReader("abcd"), 32)
	if s, err := buf.Peek(2); string(s) != "ab" || err != nil {
		t.Errorf(`Peek(2) on "abcd", EOF = %q, %v; want "ab", nil`, string(s), err)
	}
	if s, err := buf.Peek(4); string(s) != "abcd" || err != nil {

	}
	f.pos += int64(len(b))
	return len(b), nil
}

func (f *testFile) Seek(pos int64, whence int) (int64, error) {
	if pos == 0 && whence == io.SeekCurrent {
		return f.pos, nil
	}
	if len(f.ops) == 0 {
		return 0, errors.New("unexpected Seek operation")
	}
	s, ok := f.ops[0].(int64)
	if !ok {
		return 0, errors.New("unexpected Seek operation")
	}

	if s != pos || whence != io.SeekCurrent {

	{"X2", "X2"},
	{"X3", "X3"},
	{"X4", "X4"},
	{"X5", "X5"},
	{"X6", "X6"},
	{"X7", "X7"},
	{"X8", "X8"},
	{"X9", "X9"},
	{"_expand_key_128<>(SB)", "_expand_key_128<>(SB)"},
	{"_seek<>(SB)", "_seek<>(SB)"},
	{"a2+16(FP)", "a2+16(FP)"},
	{"addr2+24(FP)", "addr2+24(FP)"},
	{"asmcgocall<>(SB)", "asmcgocall<>(SB)"},
	{"b+24(FP)", "b+24(FP)"},
	{"b_len+32(FP)", "b_len+32(FP)"},

pkg debug/dwarf, method (*Entry) AttrField(Attr) *Field
pkg debug/dwarf, method (*LineReader) Next(*LineEntry) error
pkg debug/dwarf, method (*LineReader) Reset()
pkg debug/dwarf, method (*LineReader) Seek(LineReaderPos)
pkg debug/dwarf, method (*LineReader) SeekPC(uint64, *LineEntry) error
pkg debug/dwarf, method (*LineReader) Tell() LineReaderPos
pkg debug/dwarf, method (*Reader) AddressSize() int

	}

}

type reader struct{ io.Reader }
type readSeeker struct{ io.ReadSeeker }
type readBadSeeker struct{ io.ReadSeeker }

func (rbs *readBadSeeker) Seek(int64, int) (int64, error) { return 0, fmt.Errorf("illegal seek") }

// TestReadTruncation test the ending condition on various truncated files and
// that truncated files are still detected even if the underlying io.Reader
// satisfies io.Seeker.

		r.File = make([]*File, 0, end.directoryRecords)
	}
	r.Comment = end.comment
	rs := io.NewSectionReader(rdr, 0, size)
	if _, err = rs.Seek(r.baseOffset+int64(end.directoryOffset), io.SeekStart); err != nil {
		return err
	}
	buf := bufio.NewReader(rs)

	// The count of files inside a zip is truncated to fit in a uint16.