A lot of work

src/list.c

@@ -21,7 +21,7 @@ bool list_length_eq(LispVal *list, intptr_t size) {
     while (size-- && CONSP(list)) {
         list = XCDR(list);
     }
-    return size == 0;
+    return size == 0 && NILP(list);
 }
 
 DEFUN(cons, "cons", (LispVal * car, LispVal *cdr), "(car cdr)",