diff --git a/test/should-error/len_termination.pf.err b/test/should-error/len_termination.pf.err
new file mode 100644
index 0000000..63cde5b
--- /dev/null
+++ b/test/should-error/len_termination.pf.err
@@ -0,0 +1,2 @@
+./test/should-error/len_termination.pf:12.26-12.32: ill-formed recursive call
+expected first argument to be n or ls, not L