diff --git a/.ci/install-old-r-packages.R b/.ci/install-old-r-packages.R
index c445a840937c..20e8af62b0a4 100644
--- a/.ci/install-old-r-packages.R
+++ b/.ci/install-old-r-packages.R
@@ -6,7 +6,7 @@
 
 .install_packages <- function(packages) {
     install.packages(
-        pkgs = (
+        pkgs = c(
             paste("https://cran.r-project.org/src/contrib/Archive", packages, sep = "/")
             , "https://cran.r-project.org/src/contrib/praise_1.0.0.tar.gz"
         )