r-modules: fix eval

Not sure how this worked before. Now it at least evals.

1 files changed, 2 insertions, 2 deletions

diff --git a/pkgs/development/r-modules/default.nix b/pkgs/development/r-modules/default.nix
index 8a4b279179af1..7cfb8e54f2754 100644
--- a/pkgs/development/r-modules/default.nix
+++ b/pkgs/development/r-modules/default.nix
@@ -154,8 +154,8 @@ let
   overrideRDepends = overrides: old:
     lib.mapAttrs (name: value:
       (builtins.getAttr name old).overrideAttrs (attrs: {
-        nativeBuildInputs = attrs.nativeBuildInputs ++ value;
-        propagatedNativeBuildInputs = attrs.propagatedNativeBuildInputs ++ value;
+        nativeBuildInputs = (attrs.nativeBuildInputs or []) ++ value;
+        propagatedNativeBuildInputs = (attrs.propagatedNativeBuildInputs or []) ++ value;
       })
     ) overrides;