}
	case unknownVal:
		break
	default:
		panic(fmt.Sprintf("%v not Int or Float", x))
	}
	return unknownVal{}
}

// MakeImag returns the [Complex] value x*i;
// x must be [Int], [Float], or [Unknown].
// If x is [Unknown], the result is [Unknown].
func MakeImag(x Value) Value {
	switch x.(type) {
	case unknownVal:
		return x
	case int64Val, intVal, ratVal, floatVal:
		return makeComplex(int64Val(0), x)

	// TODO: add preferred region to -u-rg-.
	if e := w.Extensions(); len(e) > 0 {
		b := language.Builder{}
		b.SetTag(tt)
		for _, e := range e {
			b.AddExt(e)
		}
		tt = b.Make()
	}
	return makeTag(tt), index, c
}

// ErrMissingLikelyTagsData indicates no information was available
// to compute likely values of missing tags.
var ErrMissingLikelyTagsData = errors.New("missing likely tags data")

pkg go/constant, func MakeFloat64(float64) Value
pkg go/constant, func MakeFromBytes([]uint8) Value
pkg go/constant, func MakeFromLiteral(string, token.Token, uint) Value
pkg go/constant, func MakeImag(Value) Value
pkg go/constant, func MakeInt64(int64) Value
pkg go/constant, func MakeString(string) Value
pkg go/constant, func MakeUint64(uint64) Value
pkg go/constant, func MakeUnknown() Value

		{"Int64Val", Func, 5},
		{"Kind", Type, 5},
		{"Make", Func, 13},
		{"MakeBool", Func, 5},
		{"MakeFloat64", Func, 5},
		{"MakeFromBytes", Func, 5},
		{"MakeFromLiteral", Func, 5},
		{"MakeImag", Func, 5},
		{"MakeInt64", Func, 5},
		{"MakeString", Func, 5},
		{"MakeUint64", Func, 5},
		{"MakeUnknown", Func, 5},
		{"Num", Func, 5},
		{"Real", Func, 5},
		{"Shift", Func, 5},