public static ExpressionType nullable(DataType type) {
   return nullableTypes[type.ordinal()];
 }
 public static ExpressionType of(DataType type) {
   return types[type.ordinal()];
 }
 public static ExpressionType of(DataType type, boolean nullable) {
   int ordinal = type.ordinal();
   return nullable ? nullableTypes[ordinal] : types[ordinal];
 }
 private ExpressionType(DataType dataType) {
   this(dataType, dataType.implicitlyNullable());
 }