Array.hashCode should acually hash the data contained

[scabug]

Currently, Array.hashCode returns different values for different arrays, even if they contain the same data.

Example: Array(1,2,3).hashCode == Array(1,2,3).hashCode returns false while List(1,2,3).hashCode == List(1,2,3).hashCode returns true.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-1607?orig=1
Reporter: pascalg

[scabug]

Mohsen Lesani [X] (lesani) said:

scala>  Array(1,2,3).hashCode == Array(1,2,3).hashCode
res0: Boolean = false

scala> List(1,2,3).hashCode == List(1,2,3).hashCode
res1: Boolean = true

The same in Trunk.

[scabug]

@odersky said:
Arrays are not lists. In particular, arrays are mutable, which means completely different design criteria for hashcode and equals.

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Simon Sotak (the21st) said (edited on Mar 31, 2016 2:51:29 PM UTC):
But the same thing works as expected for mutable scala collections, so shouldn't it work for (mutable) Arrays?

scala> mutable.Seq(1, 2).hashCode == mutable.Seq(1, 2).hashCode
res0: Boolean = true

[scabug]

@SethTisue said:
since Scala 2.8, Scala arrays are just Java arrays, so we aren't free to make the hashCode method return a different answer than Java does.

scala.collection.mutable.WrappedArray, on the other hand, behaves as you would like.