Additional test for unnecessary_placeholder_linter()

[IndrajeetPatil]

To make sure that we don't lint valid usage of placeholder here:

library(magrittr)
1:4 %>% { sum(.) }
#> [1] 10
x <- 1:4
x %<>% { sum(.) }
x
#> [1] 10

^{Created on 2022-12-12 with reprex v2.0.2}

Without the placeholder, the results are incorrect:

library(magrittr)
1:4 %>% { sum() }
#> [1] 0

x <- 1:4
x %<>% { sum() }
x
#> [1] 0

^{Created on 2022-12-12 with reprex v2.0.2}

[MichaelChirico]

sorry, a bit confused at the PR description vs actual update. is the outcome of this not the same?

1:4 %>% sum()
x = 1:4
x %<>% sum()

[IndrajeetPatil]

Sorry for the confusion:

The examples in the top-level comment were just to show how a placeholder (.) is needed here and that it'd be good to have a test that ensures that we are not producing a false positive in such contexts (we aren't).

It's important that there not be a false positive here because the lint message recommends removing ., and that would produce an incorrect result here:

library(magrittr)
1:4 %>% { sum() }
#> [1] 0

x <- 1:4
x %<>% { sum() }
x
#> [1] 0

^{Created on 2022-12-12 with reprex v2.0.2}

[codecov-commenter]

Codecov Report

Merging #1838 (67860f4) into main (7dfe5d6) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1838   +/-   ##
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  Coverage   98.86%   98.86%           
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  Files         112      112           
  Lines        4839     4839           
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  Hits         4784     4784           
  Misses         55       55           

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