Exception#to_s should actually call to_s.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30531 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Jan 13 06:27:29 2011  Ryan Davis  <ryand-ruby@zenspider.com>
+
+	* error.c: Exception#to_s should actually call to_s.
+
 Thu Jan 13 00:32:54 2011  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* addr2line.c (get_nth_dirname): decrement the directory index

error.c

@@ -522,9 +522,12 @@ static VALUE
 exc_to_s(VALUE exc)
 {
     VALUE mesg = rb_attr_get(exc, rb_intern("mesg"));
+    VALUE r = Qnil;
 
     if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
-    return rb_String(mesg);
+    r = rb_String(mesg);
+    OBJ_INFECT(r, exc);
+    return r;
 }
 
 /*