presto-main/src/main/java/io/prestosql/cost/ScalarStatsCalculator.java/ScalarStatsCalculator/calculate
class ScalarStatsCalculator:    public SymbolStatsEstimate calculate(Expression scalarExpression, PlanNodeStatsEstimate inputStatistics, Session session, TypeProvider types)
    {
        return new Visitor(inputStatistics, session, types).process(scalarExpression);
    }