presto-parser/src/main/java/io/prestosql/type/TypeCalculation.java/TypeCalculation/visitArithmeticUnary
class TypeCalculation:        @Override
        public BigInteger visitArithmeticUnary(ArithmeticUnaryContext ctx)
        {
            BigInteger value = visit(ctx.expression());
            switch (ctx.operator.getType()) {
                case PLUS:
                    return value;
                case MINUS:
                    return value.negate();
                default:
                    throw new IllegalStateException("Unsupported unary operator " + ctx.operator.getText());
            }
        }