1 files changed, 3 insertions, 1 deletions
diff --git a/eval.c b/eval.c
index 1471e9be..162b0c91 100644
--- a/eval.c
+++ b/eval.c
@@ -1506,7 +1506,9 @@ static val transform_op(val forms, val syms, val rg)
     val fi = first(forms);
     val re = rest(forms);
 
-    if (fi == var_s) {
+    /* This handles improper list forms like (a b c . @42)
+       when the recursion hits the @42 part. */
+    if (fi == var_s && integerp(car(re))) {
       cons_bind (outsyms, outforms, transform_op(cons(forms, nil), syms, rg)); 
       return cons(outsyms, rlcp(car(outforms), outforms));
     }