expect error
}

func (w errorWriterTest) Write(p []byte) (int, error) {
	return len(p) * w.n / w.m, w.err
}

var errorWriterTests = []errorWriterTest{
	{0, 1, nil, io.ErrShortWrite},
	{1, 2, nil, io.ErrShortWrite},
	{1, 1, nil, nil},
	{0, 1, io.ErrClosedPipe, io.ErrClosedPipe},
	{1, 2, io.ErrClosedPipe, io.ErrClosedPipe},
	{1, 1, io.ErrClosedPipe, io.ErrClosedPipe},
}

func TestWriteErrors(t *testing.T) {

(CMPconst (MOVBUreg _) [c]) && 0xff < c => (FlagConstant [subFlags32(0, 1)])
(CMPconst (MOVHUreg _) [c]) && 0xffff < c => (FlagConstant [subFlags32(0, 1)])
(CMPconst (ANDconst _ [m]) [n]) && 0 <= m && m < n => (FlagConstant [subFlags32(0, 1)])
(CMPconst (SRLconst _ [c]) [n]) && 0 <= n && 0 < c && c <= 32 && (1<<uint32(32-c)) <= uint32(n) => (FlagConstant [subFlags32(0, 1)])

// absorb flag constants into branches

(Xor(64|32|16|8) ...) => (XOR(Q|L|L|L) ...)
(Com(64|32|16|8) ...) => (NOT(Q|L|L|L) ...)

(Neg(64|32|16|8) ...) => (NEG(Q|L|L|L) ...)
(Neg32F x) => (PXOR x (MOVSSconst <typ.Float32> [float32(math.Copysign(0, -1))]))
(Neg64F x) => (PXOR x (MOVSDconst <typ.Float64> [math.Copysign(0, -1)]))

// Lowering boolean ops
(AndB ...) => (ANDL ...)
(OrB ...) => (ORL ...)
(Not x) => (XORLconst [1] x)

// Lowering pointer arithmetic

				continue
			}

			if err == nil || !strings.Contains(err.Error(), tt.errStr) {
				t.Errorf("%s#%d got %q want %q", prefix, i, err, tt.errStr)
			}
		}
	}

	const maxInt = int(^uint(0) >> 1)

	runTestCases("", []testCase{
		0: {"--", -2147483647, "negative"},
		1: {"", maxInt, ""},
		2: {"-", 10, ""},
		3: {"gopher", 0, ""},
		4: {"-", -1, "negative"},
		5: {"--", -102, "negative"},

				case 8:
					min = w.AuxInt - delta
					max = int64(^uint64(0)>>1) - delta

					vmin = parent.NewValue0I(parent.Pos, OpConst64, parent.Func.Config.Types.Int64, min)
					vmax = parent.NewValue0I(parent.Pos, OpConst64, parent.Func.Config.Types.Int64, max)

				case 4:
					min = int64(int32(w.AuxInt) - int32(delta))
					max = int64(int32(^uint32(0)>>1) - int32(delta))

	t.Log("\n\nCOMMENT\n\n")

	// Changing the program text without affecting the compiled package
	// should result in the package being rebuilt but nothing more.
	tg.tempFile("src/p1/p1.go", "package p1\nvar X = 01\n")
	tg.run("test", "-p=1", "-x", "-v", "-short", "t/...")
	tg.grepStdout(`ok  \tt/t1\t\(cached\)`, "did not cache t1")
	tg.grepStdout(`ok  \tt/t2\t\(cached\)`, "did not cache t2")

(Rsh(16|8)Ux8  <t> x y) => (LOCGR {s390x.GreaterOrEqual} <t> (SRW <t> (MOV(H|B)Zreg x) y) (MOVDconst [0]) (CMPWUconst (MOVBZreg y) [64]))

// Signed right shift needs to return 0/-1 if shift amount is >= width of shifted value.
// We implement this by setting the shift value to 63 (all ones) if the shift value is more than 63.
//   result = arg >> (shift >= 64 ? 63 : shift)

		t.Errorf("no syntax.Selection found with syntax %q", segment)
	}
}

// indexFor returns the index into s corresponding to the position pos.
func indexFor(s string, pos syntax.Pos) int {
	i, line := 0, 1 // string index and corresponding line
	target := int(pos.Line())
	for line < target && i < len(s) {
		if s[i] == '\n' {
			line++
		}
		i++
	}
	return i + int(pos.Col()-1) // columns are 1-based

			w.end <- struct{}{}
		}(w)
	}

	maxbg := maxbg
	// for runtime.NumCPU() < 4 ||  runtime.GOMAXPROCS(0) == 1, do not change maxbg.
	// Because there is not enough CPU to parallel the testing of multiple packages.
	if runtime.NumCPU() > 4 && runtime.GOMAXPROCS(0) != 1 {
		for _, w := range worklist {
			// See go.dev/issue/65164
			// because GOMAXPROCS=2 runtime CPU usage is low,

(Select1 (Add64carry x y c)) => (ADDZEzero (Select1 <typ.UInt64> (ADDE x y (Select1 <typ.UInt64> (ADDCconst c [-1])))))
// Fold initial carry bit if 0.
(ADDE x y (Select1 <typ.UInt64> (ADDCconst (MOVDconst [0]) [-1]))) => (ADDC x y)
// Fold transfer of CA -> GPR -> CA. Note 2 uses when feeding into a chained Add64carry.
(Select1 (ADDCconst n:(ADDZEzero x) [-1])) && n.Uses <= 2 => x
(ADDE (MOVDconst [0]) y c) => (ADDZE y c)