System.Linq.Expressions.BinaryExpression.GetBinaryOpFromAssignmentOp C# (CSharp) Метод

        private static ExpressionType GetBinaryOpFromAssignmentOp(ExpressionType op)
        {
            Debug.Assert(IsOpAssignment(op));
            switch (op)
            {
                case ExpressionType.AddAssign:
                    return ExpressionType.Add;
                case ExpressionType.AddAssignChecked:
                    return ExpressionType.AddChecked;
                case ExpressionType.SubtractAssign:
                    return ExpressionType.Subtract;
                case ExpressionType.SubtractAssignChecked:
                    return ExpressionType.SubtractChecked;
                case ExpressionType.MultiplyAssign:
                    return ExpressionType.Multiply;
                case ExpressionType.MultiplyAssignChecked:
                    return ExpressionType.MultiplyChecked;
                case ExpressionType.DivideAssign:
                    return ExpressionType.Divide;
                case ExpressionType.ModuloAssign:
                    return ExpressionType.Modulo;
                case ExpressionType.PowerAssign:
                    return ExpressionType.Power;
                case ExpressionType.AndAssign:
                    return ExpressionType.And;
                case ExpressionType.OrAssign:
                    return ExpressionType.Or;
                case ExpressionType.RightShiftAssign:
                    return ExpressionType.RightShift;
                case ExpressionType.LeftShiftAssign:
                    return ExpressionType.LeftShift;
                case ExpressionType.ExclusiveOrAssign:
                    return ExpressionType.ExclusiveOr;
                default:
                    throw ContractUtils.Unreachable;
            }
        }