WITH one AS NOT MATERIALIZED (
      SELECT 1 AS value, 'one' AS name
    )
    SELECT *
    FROM one

As srcreigh said, this is the default since I believe PostgreSQL 12, as long as the CTE is only used a single time. If you use it more than once, it by default wants to materialize it instead of recalculating each time. You can also force materialization by dropping the `NOT`.

Also note that materialization acts as an optimization fence. That is, PostgreSQL will not push down filter criteria and such from the query into the `WITH` clause. It can do such if it's not materialized.