presto-main/src/main/java/io/prestosql/sql/planner/ExpressionExtractor.java/ExpressionExtractor/visitApply
class ExpressionExtractor:        @Override
        public Void visitApply(ApplyNode node, Void context)
        {
            node.getSubqueryAssignments().getExpressions().forEach(consumer);
            return super.visitApply(node, context);
        }