message: fixed types in catalan.bril
diff: n2: int = sub n idx;
  v1: int = call @catalan idx;
  v2: int = call @catalan n2;
  - elti = mul v1 v2;
  + elti: int = mul v1 v2;
  sum: int = add sum elti;
  idx: int = add idx one;
  jmp .while;
  