Nullable support ? in F# - [RFC FS-1060] discussion/questions

[jkone27]

question on RFC FS-1060

Q: just a small question what was the reason for adopting a typscript like synthax vs a C# like for nullable ref types and value types? probably there is a valid reason for preferring a typescript approach of string | null? If so, would it be possible to type alias string? to string | null to make the 2 equivalent?

let x : string? = null // C# approach

type string? = string nullable // Nullable<String> a possible definition of nullable?

//  as an "alternative" idea, this seems like a Higher order type in other languages 
// taking a type as parameter ?
type nullable<'a> = 'a | null 

// Make null the value of NullableOption.None ? then this could keep  NullableOption.Map and so on....
type NullOption =
    | Some of 'a
    |  null 
      

would that be a kind of anonymous discriminated union with "automatic" constructor? (like we have anonymous records),
would it work possibly for other "anonymous unions" ?

let x : string | null | int = 5 // anonymous DU

[kerams]

https://github.com/fsharp/fslang-design/blob/main/RFCs/FS-1060-nullable-reference-types.md#alternatives

[vzarytovskii]

Reasoning was that it can be more uniform with anonymous unions and potential future literal types.

Aliasing string? is out of scope right now.