Joins and set operations queries not reused in CTEs

[mgirlich]

library(dbplyr)
library(dplyr, warn.conflicts = FALSE)

lf1 <- lazy_frame(x = 1, .name = "lf1")
lf <- lf1 %>% 
  filter(x == 1)

# the CTE for `lf` is reused
union_all(
  lf,
  lf
) %>% 
  show_query(cte = TRUE)
#> <SQL>
#> WITH `q01` AS (
#>   SELECT *
#>   FROM `lf1`
#>   WHERE (`x` = 1.0)
#> )
#> (
#>   SELECT *
#>   FROM `q01`
#> )
#> UNION ALL
#> (
#>   SELECT *
#>   FROM `q01`
#> )

# the CTE for `lf` is not reused
lf <- lf1 %>% 
  inner_join(lf1, by = "x")
union_all(
  lf,
  lf
) %>% 
  show_query(cte = TRUE)
#> <SQL>
#> WITH `q01` AS (
#>   SELECT `lf1_LHS`.`x` AS `x`
#>   FROM `lf1` AS `lf1_LHS`
#>   INNER JOIN `lf1` AS `lf1_RHS`
#>     ON (`lf1_LHS`.`x` = `lf1_RHS`.`x`)
#> ),
#> `q02` AS (
#>   SELECT `lf1_LHS`.`x` AS `x`
#>   FROM `lf1` AS `lf1_LHS`
#>   INNER JOIN `lf1` AS `lf1_RHS`
#>     ON (`lf1_LHS`.`x` = `lf1_RHS`.`x`)
#> )
#> (
#>   SELECT *
#>   FROM `q01`
#> )
#> UNION ALL
#> (
#>   SELECT *
#>   FROM `q02`
#> )

^{Created on 2022-08-16 by the reprex package (v2.0.1)}