presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/ExtractSpatialJoins.java/ExtractSpatialJoins/newGeometrySymbol
class ExtractSpatialJoins:    private static Optional<Symbol> newGeometrySymbol(Context context, Expression expression, Metadata metadata)
    {
        if (expression instanceof SymbolReference) {
            return Optional.empty();
        }

        return Optional.of(context.getSymbolAllocator().newSymbol(expression, metadata.getType(GEOMETRY_TYPE_SIGNATURE)));
    }