hash comparisons for F# collection types

hash.fsx

// different hashes because different Seq object instances
> hash ([|1;2;3|] |> Seq.ofArray);;
val it : int = 851672095

> hash ([|1;2;3|] |> Seq.ofArray);;
val it : int = -1641179064

// same hash because Seq.ofList is just returning the list cast to IEnumerable<'t>
> hash ([1;2;3] |> Seq.ofList);;
val it : int = 1956583134

> hash ([1;2;3] |> Seq.ofList);;
val it : int = 1956583134

// same hash because list literals are structurally comparable
> hash [1;2;3];;
val it : int = 1956583134

> hash [1;2;3];;
val it : int = 1956583134

// same for F# array literals (though maybe not .Net BCL arrays?
> hash [|1;2;3|];;
val it : int = 6327

> hash [|1;2;3|];;
val it : int = 6327

// different here for the same reason as the first example
> hash (seq {1..3});;
val it : int = 1600387598

> hash (seq {1..3});;
val it : int = -606300310