Question

I know I can’t overload a return type (I think I know this).

void F()
{
}

bool F()
{
   return true;
}

..produces error already defines a member called 'F' with the same parameter types

However, I’m reading the documentation for ISet from MSDN, and I think I see the two Add methods that only vary by return type.

What is going on here?

Answer 1

The first “Add” method is actually ICollection<T>.Add, which is inherited.

When this is implemented in a class, at least one of the two Add methods will need to be explicitly implemented, ie:

void ICollection<T>.Add(T item)
{
   // ... Implement here