br.ReadRune()
	br.Discard(1)
	if err := br.UnreadRune(); err == nil {
		t.Error("UnreadRune didn't fail after Discard")
	}
}

func TestNoUnreadByteAfterDiscard(t *testing.T) {
	br := NewReader(strings.NewReader("example"))
	br.ReadByte()
	br.Discard(1)
	if err := br.UnreadByte(); err == nil {
		t.Error("UnreadByte didn't fail after Discard")
	}
}

	if err != nil {
		t.Fatal(err)
	}
	for i, f := range z.File {
		r, err := f.Open()
		if err != nil {
			continue
		}
		if f.UncompressedSize64 < 1e6 {
			n, err := io.Copy(io.Discard, r)
			if i == 3 && err != io.ErrUnexpectedEOF {
				t.Errorf("File[3] error = %v; want io.ErrUnexpectedEOF", err)
			}
			if err == nil && uint64(n) != f.UncompressedSize64 {

computed modulo 2<sup><i>n</i></sup>, where <i>n</i> is the bit width of
the <a href="#Numeric_types">unsigned integer</a>'s type.
Loosely speaking, these unsigned integer operations
discard high bits upon overflow, and programs may rely on "wrap around".
</p>
<p>
For signed integers, the operations <code>+</code>,
<code>-</code>, <code>*</code>, <code>/</code>, and <code>&lt;&lt;</code> may legally

				}
				cnt++
				if s2 == "manual" {
					if _, err = tr.writeTo(io.Discard); err != nil {
						break
					}
				}
			}
			if err != v.err {
				t.Errorf("test %d, NewReader(%s) with %s discard: got %v, want %v",
					i, s1, s2, err, v.err)
			}
			if cnt != v.cnt {
				t.Errorf("test %d, NewReader(%s) with %s discard: got %d headers, want %d headers",
					i, s1, s2, cnt, v.cnt)
			}
		}
	}

	}
	if err := w.Flush(); err != nil {
		t.Fatal(err)
	}
	if buf.Len() == 0 {
		t.Fatal("No bytes written after Flush")
	}
}

func TestWriterDir(t *testing.T) {
	w := NewWriter(io.Discard)
	dw, err := w.Create("dir/")
	if err != nil {
		t.Fatal(err)
	}
	if _, err := dw.Write(nil); err != nil {
		t.Errorf("Write(nil) to directory: got %v, want nil", err)
	}

}

// addToFlag appends args to flag.
func (p *Package) addToFlag(flag string, args []string) {
	if flag == "CFLAGS" {
		// We'll also need these when preprocessing for dwarf information.
		// However, discard any -g options: we need to be able
		// to parse the debug info, so stick to what we expect.
		for _, arg := range args {
			if !strings.HasPrefix(arg, "-g") {
				p.GccOptions = append(p.GccOptions, arg)
			}
		}

pkg io, type ReadSeekCloser interface, Close() error
pkg io, type ReadSeekCloser interface, Read([]uint8) (int, error)
pkg io, type ReadSeekCloser interface, Seek(int64, int) (int64, error)
pkg io, var Discard Writer
pkg io/fs, const ModeAppend = 1073741824
pkg io/fs, const ModeAppend FileMode
pkg io/fs, const ModeCharDevice = 2097152
pkg io/fs, const ModeCharDevice FileMode
pkg io/fs, const ModeDevice = 67108864

<code>-</code>, <code>*</code>, and <code>&lt;&lt;</code> are
computed modulo 2<sup><i>n</i></sup>, where <i>n</i> is the bit width of
the unsigned integer's type.
Loosely speaking, these unsigned integer operations
discard high bits upon overflow, and programs may rely on "wrap around".
</p>

<p>
For signed integers, the operations <code>+</code>,
<code>-</code>, <code>*</code>, <code>/</code>, and <code>&lt;&lt;</code> may legally

			err = ErrBufferFull
		}
	}
	return b.buf[b.r : b.r+n], err
}

// Discard skips the next n bytes, returning the number of bytes discarded.
//
// If Discard skips fewer than n bytes, it also returns an error.
// If 0 <= n <= b.Buffered(), Discard is guaranteed to succeed without
// reading from the underlying io.Reader.
func (b *Reader) Discard(n int) (discarded int, err error) {
	if n < 0 {
		return 0, ErrNegativeCount
	}

	// one or more "header files" until it finds a "normal file".
	format := FormatUSTAR | FormatPAX | FormatGNU
	for {
		// Discard the remainder of the file and any padding.
		if err := discard(tr.r, tr.curr.physicalRemaining()); err != nil {
			return nil, err
		}
		if _, err := tryReadFull(tr.r, tr.blk[:tr.pad]); err != nil {
			return nil, err
		}
		tr.pad = 0