func allNumeric(t Type) bool         { return allBasic(t, IsNumeric) }
func allString(t Type) bool          { return allBasic(t, IsString) }
func allOrdered(t Type) bool         { return allBasic(t, IsOrdered) }
func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }

// allBasic reports whether under(t) is a basic type with the specified info.
// If t is a type parameter, the result is true if isBasic(t, info) is true

func allNumeric(t Type) bool         { return allBasic(t, IsNumeric) }
func allString(t Type) bool          { return allBasic(t, IsString) }
func allOrdered(t Type) bool         { return allBasic(t, IsOrdered) }
func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }

// allBasic reports whether under(t) is a basic type with the specified info.
// If t is a type parameter, the result is true if isBasic(t, info) is true

	}

	x.mode = value
}

var binaryOpPredicates opPredicates

func init() {
	// Setting binaryOpPredicates in init avoids declaration cycles.
	binaryOpPredicates = opPredicates{
		token.ADD: allNumericOrString,
		token.SUB: allNumeric,
		token.MUL: allNumeric,
		token.QUO: allNumeric,
		token.REM: allInteger,

		token.AND:     allInteger,
		token.OR:      allInteger,
		token.XOR:     allInteger,

	}

	x.mode = value
}

var binaryOpPredicates opPredicates

func init() {
	// Setting binaryOpPredicates in init avoids declaration cycles.
	binaryOpPredicates = opPredicates{
		syntax.Add: allNumericOrString,
		syntax.Sub: allNumeric,
		syntax.Mul: allNumeric,
		syntax.Div: allNumeric,
		syntax.Rem: allInteger,

		syntax.And:    allInteger,
		syntax.Or:     allInteger,
		syntax.Xor:    allInteger,