[Bug #668](Closed) BigDecimal#to_r $B$,$"$j$^$;$s(B

e$B%A%1%C%He(B #668 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B%9%F!<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B

fixed by r20191

http://redmine.ruby-lang.org/issues/show/668