presto-main/src/main/java/io/prestosql/sql/planner/optimizations/UnaliasSymbolReferences.java/UnaliasSymbolReferences/visitIndexSource
class UnaliasSymbolReferences:        @Override
        public PlanNode visitIndexSource(IndexSourceNode node, RewriteContext<Void> context)
        {
            return new IndexSourceNode(node.getId(), node.getIndexHandle(), node.getTableHandle(), canonicalize(node.getLookupSymbols()), node.getOutputSymbols(), node.getAssignments(), node.getCurrentConstraint());
        }