IsInteger
	IsUnsigned
	IsFloat
	IsComplex
	IsString
	IsUntyped

	IsOrdered   = IsInteger | IsFloat | IsString
	IsNumeric   = IsInteger | IsFloat | IsComplex
	IsConstType = IsBoolean | IsNumeric | IsString
)

// A Basic represents a basic type.
type Basic struct {
	kind BasicKind
	info BasicInfo
	name string
}

// Kind returns the kind of basic type b.

	if isComplex(Vu) && isComplex(Tu) {
		return true
	}

	// "V is an integer or a slice of bytes or runes and T is a string type"
	if (isInteger(Vu) || isBytesOrRunes(Vu)) && isString(Tu) {
		return true
	}

	// "V is a string and T is a slice of bytes or runes"
	if isString(Vu) && isBytesOrRunes(Tu) {
		return true
	}

	// package unsafe:

	case int64:
		return v, nil
	case int:
		return int64(v), nil
	case string:
		i, err := strconv.Atoi(v)
		return int64(i), err
	default:
		return 0, errors.New("Invalid number format")
	}
}

// isString - Safely check if val is of type string without causing panic.
func isString(val interface{}) bool {
	_, ok := val.(string)
	return ok
}

// ContentLengthRange - policy content-length-range field.

	if isComplex(Vu) && isComplex(Tu) {
		return true
	}

	// "V is an integer or a slice of bytes or runes and T is a string type"
	if (isInteger(Vu) || isBytesOrRunes(Vu)) && isString(Tu) {
		return true
	}

	// "V is a string and T is a slice of bytes or runes"
	if isString(Vu) && isBytesOrRunes(Tu) {
		return true
	}

	// package unsafe:

func isFloat(t Type) bool          { return isBasic(t, IsFloat) }
func isComplex(t Type) bool        { return isBasic(t, IsComplex) }
func isNumeric(t Type) bool        { return isBasic(t, IsNumeric) }
func isString(t Type) bool         { return isBasic(t, IsString) }
func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
func isConstType(t Type) bool      { return isBasic(t, IsConstType) }

    public val KaType.isBoolean: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.BOOLEAN) }
    public val KaType.isString: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.STRING) }
    public val KaType.isCharSequence: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.CHAR_SEQUENCE) }

	Float32:       {Float32, IsFloat, "float32"},
	Float64:       {Float64, IsFloat, "float64"},
	Complex64:     {Complex64, IsComplex, "complex64"},
	Complex128:    {Complex128, IsComplex, "complex128"},
	String:        {String, IsString, "string"},
	UnsafePointer: {UnsafePointer, 0, "Pointer"},

	UntypedBool:    {UntypedBool, IsBoolean | IsUntyped, "untyped bool"},
	UntypedInt:     {UntypedInt, IsInteger | IsUntyped, "untyped int"},

	Float32:       {Float32, IsFloat, "float32"},
	Float64:       {Float64, IsFloat, "float64"},
	Complex64:     {Complex64, IsComplex, "complex64"},
	Complex128:    {Complex128, IsComplex, "complex128"},
	String:        {String, IsString, "string"},
	UnsafePointer: {UnsafePointer, 0, "Pointer"},

	UntypedBool:    {UntypedBool, IsBoolean | IsUntyped, "untyped bool"},
	UntypedInt:     {UntypedInt, IsInteger | IsUntyped, "untyped int"},

	valid := false
	length := int64(-1) // valid if >= 0
	switch typ := under(x.typ).(type) {
	case *Basic:
		if isString(typ) {
			valid = true
			if x.mode == constant_ {
				length = int64(len(constant.StringVal(x.val)))
			}
			// an indexed string always yields a byte value
			// (not a constant) even if the string and the
			// index are constant
			x.mode = value
			x.typ = universeByte // use 'byte' name
		}

// a string, the result is of type (possibly untyped) string.
func coreString(t Type) Type {
	t = Unalias(t)
	tpar, _ := t.(*TypeParam)
	if tpar == nil {
		return under(t) // string or untyped string
	}

	var su Type
	hasString := false
	if tpar.underIs(func(u Type) bool {
		if u == nil {
			return false
		}
		if isString(u) {
			u = NewSlice(universeByte)