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) }

		v1.AddArg2(v2, mem)
		v.AddArg2(v0, v1)
		return true
	}
	// match: (Load <t> ptr mem)
	// cond: t.IsString()
	// result: (StringMake (Load <typ.BytePtr> ptr mem) (Load <typ.Int> (OffPtr <typ.IntPtr> [config.PtrSize] ptr) mem))
	for {
		t := v.Type
		ptr := v_0
		mem := v_1
		if !(t.IsString()) {
			break
		}
		v.reset(OpStringMake)
		v0 := b.NewValue0(v.Pos, OpLoad, typ.BytePtr)
		v0.AddArg2(ptr, mem)

    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
		}

	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)

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) }

		base.Errorf("invalid operation: %v (type %v does not support indexing)", n, t)
		n.SetType(nil)
		return n

	case types.TSTRING, types.TARRAY, types.TSLICE:
		n.Index = indexlit(n.Index)
		if t.IsString() {
			n.SetType(types.ByteType)
		} else {
			n.SetType(t.Elem())
		}
		why := "string"
		if t.IsArray() {
			why = "array"
		} else if t.IsSlice() {
			why = "slice"
		}