[ruby-core:72887] [Ruby trunk - Bug #7676] Comparison of Float::NAN in array behaves unexpectedly

Issue #7676 has been updated by Dwain Faithfull.


It appears calling eql? on array does not behave in this way:
~~~
[Float::NAN].eql? [Float::NAN]
=> false
~~~

Should we aim for consistency between these methods? Does it make sense for one to have an identity check and for the other not to?

I believe it doesn't really make sense for == to have an identity check, as the example in #3 is not how I'd expect Ruby to behave.

----------------------------------------
Bug #7676: Comparison of Float::NAN in array behaves unexpectedly
https://bugs.ruby-lang.org/issues/7676#change-56120

* Author: Simon Russell
* Status: Open
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* ruby -v: ruby 1.9.3p362 (2012-12-25 revision 38607) [x86_64-linux]
* Backport: 
----------------------------------------
It seems that two arrays containing Float::NAN will be considered equal ([Float::NAN] == [Float::NAN]), despite the fact that Float::NAN != Float::NAN.

Tested and reproduced in 1.8.7p371, 1.9.3p362, 2.0.0preview2. (This bug can be reproduced in Ruby 1.8 as well.)  Results below.

1.8.7 p371
---------

1.8.7 :001 > nan = 0.0/0.0
 => NaN 
1.8.7 :002 > nan == nan
 => false 
1.8.7 :003 > [nan] == [nan]
 => true 

1.9.3 p362
---------

1.9.3p362 :001 > Float::NAN == Float::NAN
 => false 
1.9.3p362 :002 > [Float::NAN] == [Float::NAN]
 => true 

2.0.0 preview2
--------------

2.0.0dev :001 > Float::NAN == Float::NAN
 => false 
2.0.0dev :002 > [Float::NAN] == [Float::NAN]
 => true

---Files--------------------------------
bug-7676.patch (1.67 KB)


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