.NET Generics Type Constraint Inequality

I am trying to implement two common interfaces. It makes sense that both ITwoWayMapper<T,U>

will implement IOneWayMapper<T,U>

and IOneWayMapper<U,T>

. So if I try to do exactly this:

public interface IOneWayMapper<T, U>
{
    U Map(T source);
}

public interface ITwoWayMapper<T, U> :
    IOneWayMapper<T, U>,
    IOneWayMapper<U, T>
{
    TTwo Map(TOne source);
    TOne Map(TTwo source);
}

      

        
        
        
      

    

I am getting an error Interface ITwoWayMapper<T,U> cannot implement both IOneWayMapper<T,U> and IOneWayMapper<U,T> because they may unify for some type parameter substitutions

. So I think it's good that it makes sense as it is ambiguous because it couldn't figure out which interface is being executed.

So this leads to my question: can type constraints be used to say something like this ?:

public interface ITwoWayMapper<T, U> :
    IOneWayMapper<T, U>,
    IOneWayMapper<U, T>
    where T: !U
{
    TTwo Map(TOne source);
    TOne Map(TTwo source);
}