Array.indexOf broken for Double.NaN

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scala> Array(Double.NaN) indexOf Double.NaN
res0: Int = -1

scala>

Actual: -1, Expected: 0

Scala version 2.8.0.r21376-b20100408020204 (Java HotSpot(TM) Client VM, Java 1.6.0_18).

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Imported From: https://issues.scala-lang.org/browse/SI-3291?orig=1
Reporter: Joa Ebert (joa)

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Joa Ebert (joa) said:
Double.NaN == Double.NaN is also false.

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@paulp said:
Double.NaN == Double.NaN is supposed to be false. (It's false in java too.) There is a problem with NaN, but you're not illustrating it here, and I don't think we can fix it anyway. That is that java decided to make the boxed NaNs return true on equals while keeping the primitive == false. Since we unified those worlds we can't satisfy both. See #2598.

If you really want to find NaN you need to look for it differently.

scala> Array(Double.NaN) indexWhere (_.isNaN)
res0: Int = 0