presto-main/src/main/java/io/prestosql/sql/planner/sanity/ValidateDependenciesChecker.java/Visitor/createInputs
class Visitor:        private static ImmutableSet<Symbol> createInputs(PlanNode source, Set<Symbol> boundSymbols)
        {
            return ImmutableSet.<Symbol>builder()
                    .addAll(source.getOutputSymbols())
                    .addAll(boundSymbols)
                    .build();
        }