presto-main/src/main/java/io/prestosql/sql/planner/DomainTranslator.java/Visitor/checkedTypeLookup
class Visitor:        private Type checkedTypeLookup(Symbol symbol)
        {
            Type type = types.get(symbol);
            checkArgument(type != null, "Types is missing info for symbol: %s", symbol);
            return type;
        }