presto-parser/src/main/java/io/prestosql/sql/tree/IfExpression.java/IfExpression/IfExpression
class IfExpression:    private IfExpression(Optional<NodeLocation> location, Expression condition, Expression trueValue, Expression falseValue)
    {
        super(location);
        this.condition = requireNonNull(condition, "condition is null");
        this.trueValue = requireNonNull(trueValue, "trueValue is null");
        this.falseValue = Optional.ofNullable(falseValue);
    }