> type T() = class end
- let dosmth (a: T) = System.Console.WriteLine a
- let inline NEW () = (^a : (new : unit -> ^a) ())
- let x = NEW ()
- dosmth x;;
FSI_0002+T
type T =
  new: unit -> T
val dosmth: a: T -> unit
val inline NEW: unit -> ^a when ^a: (``.ctor`` : ^a)
val x: T
val it: unit = ()

>

> type T() = class end
- let dosmth (a: T) = System.Console.WriteLine a
- let inline NEW () = (^a : (new : unit -> ^a) ())
- let x = NEW ()
- dosmth x;;

  let x = NEW ()
  ----^

stdin(4,5): error FS0030: Value restriction. The value 'x' has been inferred to have generic type
    val x: '_a when '_a: (``.ctor`` : '_a) and '_a :> T
Either define 'x' as a simple data term, make it a function with explicit arguments or, if you do not intend for it to be generic, add a type annotation.

LanguageFeature.InterfacesWithAbstractStaticMembers
LanguageFeature.SelfTypeConstraints