Cannot convert type 'Task' to 'Task'

Question

I have the following function with a delegate parameter that accepts a type of one interface and returns a task of another.

public void Bar(Func

        

Answer 1

It seems like there's got to be a cleaner way of doing this, but it is possible to create a wrapping task of the correct type. I introduced a new function called GeneralizeTask().

Task GeneralizeTask(Task task) 
    where TDerived : TBase 
{
    var newTask = new Task(() => {
        if (task.Status == TaskStatus.Created) task.Start();
        task.Wait();
        return (TBase)task.Result;
    });
    return newTask;
}

Edit:

As @EricLippert points out, this can be simplified significantly. I first tried to find such a way to implement this method, but couldn't find one that compiled. As it turned out, the real solution was even simpler than I imagined.

async Task GeneralizeTask(Task task) 
    where TDerived : TBase 
{
    return (TBase) await task;
}

You can then invoke Bar() like this.

Bar(m => GeneralizeTask(DoSomething((Message)m)));