SimpleDiagnostic GetHashCode is inconsistent

[pdelvo]

To make Microsoft.CodeAnalysis.Diagnostic work with Sets and other data structures that requires GetHashCode to be implemented correctly you have to have a GetHashCode method with this property:
x.Equals(y) \implies x.GetHashCode() == y.GetHashCode() \forall x,y

Currently SimpleDiagnostic's GetHashCode combines the hash codes of its properties including a GetHashCode on the object[] messageArgs which is using the reference to that array, not its contents to generate the hash code. Equals however is comparing the objects in the array (using Enumerable.SequenceEqual) . So currently you can have two diagnostics that are Equal in terms of IEquatable.Equals but with GetHashCode returning different values.
http://source.roslyn.codeplex.com/#Microsoft.CodeAnalysis/Diagnostic/Diagnostic_SimpleDiagnostic.cs,134
http://source.roslyn.codeplex.com/#Microsoft.CodeAnalysis/Diagnostic/Diagnostic_SimpleDiagnostic.cs,120

[VSadov]

Looks like a bug. GetHashCode should not be more specific than Equals by requiring actual reference equality of message array.