move semantics

[ufcpp]

interface INonCopyable { }

interface IMovable : INonCopyable
{
 // void OnMoved(); ?
}

static class MoveExtensions
{
 public static T Move<T>(ref this T x)
 where T : struct, IMovable
 {
 // needs interlocked exchange?
 var t = x;
 // x.OnMoved(); ?
 x = default;
 return t;
 }
}

• allow var y = x.Move();
• disallow to use x after Move

This is not so hard for local variables and parameters but fields.