I was recently wondering if there is any drawback for Set<Weakref<T>> over WeakSet<T>.
Pros:
Cons:
Am I missing something or is this almost a win-win situation? Would the Set<Weakref<T>> version prevent the garbage collector from collecting?
What you missed:
WeakSets are collections of objects only. They cannot contain arbitrary values of any type, as Sets can.
The number of objects or their traversal order is immaterial, so a WeakSet is more suitable (and performant) than a Set for tracking object references, especially if a very large number of objects is involved.
Set<Weakref<T>> will not prevent GC. Also note that WeakRef is not supported in Opera but WeakSet is.