From a193af3bef2412ee5e11d5f296b097ea6641b476 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 10 Sep 2014 15:20:36 +0900
Subject: [PATCH] deal with exceptions inside macroexpansion

---
 macro.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/macro.c b/macro.c
index d34482d3..ec627215 100644
--- a/macro.c
+++ b/macro.c
@@ -358,8 +358,6 @@ pic_macroexpand(pic_state *pic, pic_value expr, struct pic_lib *lib)
   struct pic_lib *prev;
   pic_value v;
 
-  assert(pic_eq_p(lib->env->defer, pic_nil_value()));
-
 #if DEBUG
   puts("before expand:");
   pic_debug(pic, expr);
@@ -370,6 +368,8 @@ pic_macroexpand(pic_state *pic, pic_value expr, struct pic_lib *lib)
   prev = pic->lib;
   pic->lib = lib;
 
+  lib->env->defer = pic_nil_value(); /* the last expansion could fail and leave defer field old */
+
   v = macroexpand(pic, expr, lib->env);
 
   macroexpand_deferred(pic, lib->env);