rename_at() handles empty selection.

closes #4324

Author: romainfrancois

NEWS.md

@@ -1,3 +1,7 @@
+# dplyr 0.8.1.9000
+
+* `rename_at()` handles empty selection (#4324). 
+
 # dplyr 0.8.0.9000
 
 ## Breaking changes

R/colwise-select.R

@@ -108,7 +108,11 @@ vars_select_syms <- function(vars, funs, tbl, strict = FALSE) {
     if (is_quosure(fun)) {
       fun <- quo_as_function(fun)
     }
-    syms <- set_names(syms(vars), fun(vars))
+    syms <- if (length(vars)) {
+      set_names(syms(vars), fun(vars))
+    } else {
+      set_names(syms(vars))
+    }
   } else if (!strict) {
     syms <- syms(vars)
   } else {

tests/testthat/test-colwise-select.R

@@ -182,3 +182,9 @@ test_that("select_if() and rename_if() handles logical (#4213)", {
 
 })
 
+test_that("rename_at() handles empty selection (#4324)", {
+  expect_identical(
+    mtcars %>% rename_at(vars(contains("fake_col")),~paste0("NewCol.",.)),
+    mtcars
+  )
+})