let inline tryParse<'a when 'a: (static member TryParse: string * byref<'a> -> bool)> x =
    let mutable res = Unchecked.defaultof<'a>
    if (^a: (static member TryParse: string * byref<'a> -> bool) (x, &res))
    then Some res
    else None

let a = tryParse<int>("19")
let b = tryParse<Guid>("4A9FA193-26D6-4D21-8610-02B060D43744")
let c = tryParse<DateTimeOffset>("ddd")