Linting tautological logical constructs (`if`/`else`) in `redundant_ifelse_linter()`

The first example below is an unnecessary use of conditional statement, but it currently doesn't produce any lint. We can cover this in redundant_ifelse_linter().

library(lintr)
lint(text = "if (expr) TRUE else FALSE", linters = all_linters())

lint(text = "ifelse(expr, TRUE, FALSE)", linters = all_linters())
#> <text>:1:1: warning: [redundant_ifelse_linter] Just use the logical condition (or its negation) directly instead of calling ifelse(x, TRUE, FALSE)
#> ifelse(expr, TRUE, FALSE)
#> ^~~~~~~~~~~~~~~~~~~~~~~~~

And, no, this is not as rare as one would guess.

Demonstrating the redundancy:

x <- 3L
foo1 <- function(x) {
  expr <- x > 2L
  if (expr) TRUE else FALSE # this should lint
}

foo2 <- function(x) {
  expr <- x > 2L
  expr
}

identical(foo1(x), foo2(x))
#> [1] TRUE

^{Created on 2023-09-20 with reprex v2.0.2}

Session info

``` r sessioninfo::session_info() #> ─ Session info ─────────────────────────────────────────────────────────────── #> setting value #> version R version 4.3.1 (2023-06-16) #> os macOS Ventura 13.4.1 #> system aarch64, darwin20 #> ui X11 #> language (EN) #> collate en_US.UTF-8 #> ctype en_US.UTF-8 #> tz Europe/Stockholm #> date 2023-09-20 #> pandoc 3.1.7 @ /usr/local/bin/ (via rmarkdown) #> #> ─ Packages ─────────────────────────────────────────────────────────────────── #> package * version date (UTC) lib source #> backports 1.4.1 2021-12-13 [1] CRAN (R 4.3.0) #> callr 3.7.3 2022-11-02 [1] CRAN (R 4.3.0) #> cli 3.6.1 2023-03-23 [1] CRAN (R 4.3.0) #> crayon 1.5.2 2022-09-29 [1] CRAN (R 4.3.0) #> cyclocomp 1.1.1 2023-08-30 [1] CRAN (R 4.3.0) #> data.table 1.14.8 2023-02-17 [1] CRAN (R 4.3.0) #> desc 1.4.2 2022-09-08 [1] CRAN (R 4.3.0) #> digest 0.6.33 2023-07-07 [1] CRAN (R 4.3.0) #> evaluate 0.21 2023-05-05 [1] CRAN (R 4.3.0) #> fansi 1.0.4 2023-01-22 [1] CRAN (R 4.3.0) #> fastmap 1.1.1 2023-02-24 [1] CRAN (R 4.3.0) #> fs 1.6.3 2023-07-20 [1] CRAN (R 4.3.0) #> glue 1.6.2 2022-02-24 [1] CRAN (R 4.3.0) #> htmltools 0.5.6 2023-08-10 [1] CRAN (R 4.3.1) #> knitr 1.44 2023-09-11 [1] CRAN (R 4.3.1) #> lazyeval 0.2.2 2019-03-15 [1] CRAN (R 4.3.0) #> lifecycle 1.0.3 2022-10-07 [1] CRAN (R 4.3.0) #> lintr * 3.1.0.9000 2023-09-20 [1] Github (r-lib/lintr@f8fab18) #> magrittr 2.0.3 2022-03-30 [1] CRAN (R 4.3.0) #> pillar 1.9.0 2023-03-22 [1] CRAN (R 4.3.0) #> pkgconfig 2.0.3 2019-09-22 [1] CRAN (R 4.3.0) #> processx 3.8.2 2023-06-30 [1] CRAN (R 4.3.0) #> ps 1.7.5 2023-04-18 [1] CRAN (R 4.3.0) #> purrr 1.0.2 2023-08-10 [1] CRAN (R 4.3.0) #> R.cache 0.16.0 2022-07-21 [1] CRAN (R 4.3.0) #> R.methodsS3 1.8.2 2022-06-13 [1] CRAN (R 4.3.0) #> R.oo 1.25.0 2022-06-12 [1] CRAN (R 4.3.0) #> R.utils 2.12.2 2022-11-11 [1] CRAN (R 4.3.0) #> R6 2.5.1 2021-08-19 [1] CRAN (R 4.3.0) #> remotes 2.4.2.1 2023-07-18 [1] CRAN (R 4.3.0) #> reprex 2.0.2 2022-08-17 [1] CRAN (R 4.3.0) #> rex 1.2.1 2021-11-26 [1] CRAN (R 4.3.0) #> rlang 1.1.1 2023-04-28 [1] CRAN (R 4.3.0) #> rmarkdown 2.25 2023-09-18 [1] CRAN (R 4.3.1) #> rprojroot 2.0.3 2022-04-02 [1] CRAN (R 4.3.0) #> rstudioapi 0.15.0 2023-07-07 [1] CRAN (R 4.3.0) #> sessioninfo 1.2.2 2021-12-06 [1] CRAN (R 4.3.0) #> styler 1.10.2 2023-08-29 [1] CRAN (R 4.3.1) #> tibble 3.2.1 2023-03-20 [1] CRAN (R 4.3.0) #> utf8 1.2.3 2023-01-31 [1] CRAN (R 4.3.0) #> vctrs 0.6.3 2023-06-14 [1] CRAN (R 4.3.0) #> withr 2.5.0 2022-03-03 [1] CRAN (R 4.3.0) #> xfun 0.40 2023-08-09 [1] CRAN (R 4.3.0) #> xml2 1.3.5 2023-07-06 [1] CRAN (R 4.3.0) #> xmlparsedata 1.0.5 2021-03-06 [1] CRAN (R 4.3.0) #> yaml 2.3.7 2023-01-23 [1] CRAN (R 4.3.0) #> #> [1] /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library #> #> ────────────────────────────────────────────────────────────────────────────── ```

r-lib / lintr

Linting tautological logical constructs (`if`/`else`) in `redundant_ifelse_linter()` #2196