# \[Bug #492\] defined? a && defined? b

**URL:** <https://www.ruby-forum.com/t/bug-492-defined-a-defined-b/146771>\
**Category:** Development\
**Created:** [August 25, 2008, 11:37am UTC](https://www.ruby-forum.com/t/bug-492-defined-a-defined-b/146771 "2008-08-25T11:37:25Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [August 25, 2008, 11:37am UTC](https://www.ruby-forum.com/t/bug-492-defined-a-defined-b/146771/1 "2008-08-25T11:37:25Z")

</div>

Bug #492: defined? a && defined? b  
[http://redmine.ruby-lang.org/issues/show/492](http://redmine.ruby-lang.org/issues/show/492)

e$B5/I\<\<Te(B: Shyouhei U.  
e$B%9%F!\<%?%9e(B: Open, e$BM%@hEYe(B: Normal  
e$BC4Ev\<Te(B: Yukihiro M., e$B%+%F%4%je(B: core

defined? a && defined? b  
e$B$,e(Bnile$B$K$J$j$^$9!#N\>J}Dj5A$5$l$F$k$s$@$+$ie(Bnile$B$O$\*$+$7$$$O$:$G$9!#e(B

irb(main):001:0\> [RUBY\_VERSION, RUBY\_REVISION]  
=\> [“1.9.0”, 17576]  
irb(main):002:0\> a = b = nil  
=\> nil  
irb(main):003:0\> defined? a && defined? b  
=\> nil

1.8e$B$G$Oe(Bdefined?(a && defined?  
b)e$B$H2r\<a$5$l$Fe(B"expression"e$B$K$J$j$^$9e(B

irb(main):001:0\> [RUBY\_VERSION, RUBY\_REVISION]  
=\> [“1.8.7”, 17572]  
irb(main):002:0\> a = b = nil  
=\> nil  
irb(main):003:0\> defined? a && defined? b  
=\> “expression”  
irb(main):004:0\>

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [August 25, 2008, 12:07pm UTC](https://www.ruby-forum.com/t/bug-492-defined-a-defined-b/146771/2 "2008-08-25T12:07:52Z")

</div>

e$B%A%1%C%He(B #492 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B%9%F!\<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B  
e$B?JD=e(B % 0e$B$+$ie(B100e$B$KJQ99e(B

## Applied in changeset r18834.

[http://redmine.ruby-lang.org/issues/show/492](http://redmine.ruby-lang.org/issues/show/492)