Error with pulling concept lists with nested criteria in cohort

[k-m-li]

When you have a multi-layer nested criteria in a cohort definition where the outer nested portion has only one element, you are unable to pull the concept list from the cohort: functions for pulling the list return an empty list instead. This makes it very hard to generate a working JSON.

A temp workaround can be to add an extra line into the outer nest using a dummy cs
atLeast(0, conditionOccurrence(cs(9999999, name = "dummy")))

A working example is below.

## Pass:
x <- cohort(
  entry(
    conditionOccurrence(cs(1, name = "test"),
                         nestedWithAll(
                           atLeast(1, conditionOccurrence(cs(2, name = "test2"))),
                           atLeast(1, conditionOccurrence(cs(3, name = "test3"),
                                                          nestedWithAll(atLeast(1, conditionOccurrence(cs(1, name = "test"))))
                           ))))
  )
)
Capr:::listConceptSets(x)

## Fail: returns empty list
x <- cohort(
  entry(
    conditionOccurrence(cs(1, name = "test"),
                        nestedWithAll(
                          # atLeast(1, conditionOccurrence(cs(2, name = "test2"))),
                          atLeast(1, conditionOccurrence(cs(3, name = "test3"),
                                                         nestedWithAll(atLeast(1, conditionOccurrence(cs(1, name = "test"))))
                          ))))
  )
)
Capr:::listConceptSets(x)

## Pass:
x <- entry(
  conditionOccurrence(cs(1, name = "test"),
                      nestedWithAll(
                        # atLeast(1, conditionOccurrence(cs(2, name = "test2"))),
                        atLeast(1, conditionOccurrence(cs(3, name = "test3"),
                                                       nestedWithAll(atLeast(1, conditionOccurrence(cs(1, name = "test"))))
                        ))))
)
Capr:::listConceptSets(x)

## Workaround:
x <- cohort(
  entry(
    conditionOccurrence(cs(1, name = "test"),
                        nestedWithAll(
                          atLeast(0, conditionOccurrence(cs(9999999, name = "dummy"))),
                          atLeast(1, conditionOccurrence(cs(3, name = "test3"),
                                                         nestedWithAll(atLeast(1, conditionOccurrence(cs(1, name = "test"))))
                          ))))
  )
)
Capr:::listConceptSets(x)