How do I check 'T for types not being allowed to be null?

given

let inline deserialize<'t> x :'t option = 
    printfn "Attempting to deserialize %A" typeof<'t>.Name
    try
        JsonConvert.DeserializeObject<'t>(x)
        |> Some
    with ex ->
        System.Diagnostics.Trace.WriteLine(sprintf "Error deserialization failed:%s" ex.Message)
        None

is returning for example an obj list as null. FSharpList<_> is not allowed to be null. How can I, without knowing what 't is ask F# if the type I'm about to return supports null so that I can halt/throw/act accordingly? Is there a reflection flag or Microsoft.FSharp.Reflection... method for this?