From 297e8727cb5fec9f33c8d5dfb212865d4c06f93f Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Mon, 20 Jan 2014 21:57:13 +0900
Subject: [PATCH] Fixing bug in subtraction of a ratio with a bignum numerator.

---
 bignum.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/bignum.c b/bignum.c
index 2619e104..a4724c69 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1212,6 +1212,8 @@ sexp sexp_sub (sexp ctx, sexp a, sexp b) {
     /* ... FALLTHROUGH ... */
   case SEXP_NUM_RAT_RAT:
     tmp2 = sexp_make_ratio(ctx, sexp_ratio_numerator(b), sexp_ratio_denominator(b));
+    if (sexp_bignump(sexp_ratio_numerator(tmp2)))
+      sexp_ratio_numerator(tmp2) = sexp_copy_bignum(ctx, NULL, sexp_ratio_numerator(tmp2), 0);
     sexp_negate_exact(sexp_ratio_numerator(tmp2));
     r = sexp_ratio_add(ctx, a, tmp2);
     if (negatep) {