[Bug #2584] クラス定義中の defined? yield が "yield" を返す

Bug #2584: e$B%/%i%9Dj5ACf$Ne(B defined? yield e$B$,e(B yield
e$B$rJV$9e(B
http://redmine.ruby-lang.org/issues/show/2584

e$B5/I<<Te(B: _ wanabe
e$B%9%F!<%?%9e(B: Open, e$BM%@hEYe(B: Normal
e$BC4Ev<Te(B: Koichi Sasada, e$B%+%F%4%je(B: YARV, Target version: 1.9.x
ruby -v: ruby 1.9.2dev (2010-01-09 trunk 26260) [i386-mingw32]

e$B%/%i%9Dj5ACf$Oe(B yield e$B$r8F$Y$J$$$K$b4X$o$i$:!"e(Bdefined?(yield)
e$B$,e(B yield e$B$rJV$7$^$9!#e(B

$ ruby -ve class Foo;p defined?(yield);end
ruby 1.9.2dev (2010-01-09 trunk 26260) [i386-mingw32]
yield

GET_BLOCK_PTR() e$B$O%/%i%9Dj5ACf$J$ie(B 0
e$B$rJV$9J}$,$$$$$H;W$&$N$G$9$,$I$&$G$7$g$&$+!#e(B
e$B%Q%C%A$rE:IU$7$^$9!#$J$*!"$3$N%Q%C%A$Ge(B Bug #2568
e$B$b=$@5$5$l$^$9!#e(B

e$B%A%1%C%He(B #2584 e$B$,99?7$5$l$^$7$?!#e(B (by _ wanabe)

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

e$B$9$_$^$;$s!"Fs=E$KAw?.$7$F$7$^$$$^$7$?!#e(B

http://redmine.ruby-lang.org/issues/show/2584