anchor.diff:                      let pass0 =
                           if t.IsArray || typeof<System.Array>.IsAssignableFrom t then
                               // I could do something here, but I doubt it would have any real performance impact
  -                            null
  +                            make typedefof<GenericHashParamObject<_>>
   
                           elif t.IsGenericType && ((t.GetGenericTypeDefinition ()).Equals typedefof<System.Nullable<_>>) then
                               let nt = get (t.GetGenericArguments()) 0
  
positive.code: 
                  let equalityInterfaces (t:Type) : obj =
                      let make = makeEquatableDelegate t t
  
                      let notnull =
                          let id = IntrinsicFunctions.getTypeInfo t
                          id = IntrinsicFunctions.TypeNullnessSemantics_NullNotLiked || id = IntrinsicFunctions.TypeNullnessSemantics_NullNever
  
                      let equatable = makeEquatableType t
  
  
negative.code:                 type StructEquals<'a when 'a : struct and 'a : equality>() =
                      member __.Equals (_:IEqualityComparer, x:'a, y:'a) = x.Equals y
  
                  type RefTypeNullableStructualEquality<'a when 'a : not struct and 'a : null and 'a :> IStructuralEquatable>() =
                      member __.Equals (ec:IEqualityComparer, x:'a, y:'a) =
                          match x, y with
  