{"binary _", "{{print 0b_1_0_1}}", "5", tVal, true},
	{"BINARY", "{{print 0B101}}", "5", tVal, true},
	{"octal0", "{{print 0377}}", "255", tVal, true},
	{"octal", "{{print 0o377}}", "255", tVal, true},
	{"octal _", "{{print 0o_3_7_7}}", "255", tVal, true},
	{"OCTAL", "{{print 0O377}}", "255", tVal, true},
	{"hex", "{{print 0x123}}", "291", tVal, true},
	{"hex _", "{{print 0x1_23}}", "291", tVal, true},

	{"binary _", "{{print 0b_1_0_1}}", "5", tVal, true},
	{"BINARY", "{{print 0B101}}", "5", tVal, true},
	{"octal0", "{{print 0377}}", "255", tVal, true},
	{"octal", "{{print 0o377}}", "255", tVal, true},
	{"octal _", "{{print 0o_3_7_7}}", "255", tVal, true},
	{"OCTAL", "{{print 0O377}}", "255", tVal, true},
	{"hex", "{{print 0x123}}", "291", tVal, true},
	{"hex _", "{{print 0x1_23}}", "291", tVal, true},

		// octals
		{IntLit, "0o0", "0o0", ""},
		{IntLit, "0o1234", "0o1234", ""},
		{IntLit, "0O1234", "0O1234", ""},

		{IntLit, "0o", "0o", "octal literal has no digits"},
		{IntLit, "0o8123", "0o8123", "invalid digit '8' in octal literal"},
		{IntLit, "0o1293", "0o1293", "invalid digit '9' in octal literal"},
		{IntLit, "0o12a3", "0o12 a3", ""}, // only accept 0-9

		// octals
		{token.INT, "0o0", "0o0", ""},
		{token.INT, "0o1234", "0o1234", ""},
		{token.INT, "0O1234", "0O1234", ""},

		{token.INT, "0o", "0o", "octal literal has no digits"},
		{token.INT, "0o8123", "0o8123", "invalid digit '8' in octal literal"},
		{token.INT, "0o1293", "0o1293", "invalid digit '9' in octal literal"},
		{token.INT, "0o12a3", "0o12 a3", ""}, // only accept 0-9

	_ = 0o567 // ERROR "0o/0O-style octal literal requires go1.13 or later"
	_ = 0xabc // ok
	_ = 0x0p1 // ERROR "hexadecimal floating-point literal requires go1.13 or later"

	_ = 0b111 // ERROR "binary"
	_ = 0o567 // ERROR "octal"
	_ = 0xabc // ok
	_ = 0x0p1 // ERROR "hexadecimal floating-point"

	_ = 1_000i // ERROR "underscore"
	_ = 0b111i // ERROR "binary"
	_ = 0o567i // ERROR "octal"

	_ = 0o567 // ERROR "0o/0O-style octal literal requires go1.13 or later"
	_ = 0xabc // ok
	_ = 0x0p1 // ERROR "hexadecimal floating-point literal requires go1.13 or later"

	_ = 0b111 // ERROR "binary"
	_ = 0o567 // ERROR "octal"
	_ = 0xabc // ok
	_ = 0x0p1 // ERROR "hexadecimal floating-point"

	_ = 1_000i // ERROR "underscore"
	_ = 0b111i // ERROR "binary"
	_ = 0o567i // ERROR "octal"

// of equal values.

package literals

func _() {
	// 0-octals
	assert(0_123 == 0123)
	assert(0123_456 == 0123456)

	// decimals
	assert(1_234 == 1234)
	assert(1_234_567 == 1234567)

	// hexadecimals
	assert(0X_0 == 0)
	assert(0X_1234 == 0x1234)
	assert(0X_CAFE_f00d == 0xcafef00d)

	// octals
	assert(0o0 == 0)
	assert(0o1234 == 01234)
	assert(0o01234567 == 01234567)

// Format implements [fmt.Formatter]. It accepts the formats
// 'b' (binary), 'o' (octal with 0 prefix), 'O' (octal with 0o prefix),
// 'd' (decimal), 'x' (lowercase hexadecimal), and
// 'X' (uppercase hexadecimal).
// Also supported are the full suite of package fmt's format
// flags for integral types, including '+' and ' ' for sign
// control, '#' for leading zero in octal and for hexadecimal,
// a leading "0x" or "0X" for "%#x" and "%#X" respectively,

			return 0
		}
		if inv == 0xff {
			return ^int64(x)
		}
		return int64(x)
	}

	// Normal case is base-8 (octal) format.
	return p.parseOctal(b)
}

// formatNumeric encodes x into b using base-8 (octal) encoding if possible.
// Otherwise it will attempt to use base-256 (binary) encoding.
func (f *formatter) formatNumeric(b []byte, x int64) {
	if fitsInOctal(len(b), x) {

        assertInvalidUnixPermission("812", "'812' isn't a proper Unix permission. Can't be parsed as octal number.");
        assertInvalidUnixPermission("790", "'790' isn't a proper Unix permission. Can't be parsed as octal number.");
        assertInvalidUnixPermission("649", "'649' isn't a proper Unix permission. Can't be parsed as octal number.");