Nullable Func<T, TResult>
c#, func
Solution
That doesn't make sense. All reference types, including `Func<...>`, can already be `null`.
Nullable types apply to value types (`struct`s), which cannot ordinarily be `null`.
Problem
In C# is it possible to pass a method a nullable Func? Neither `Func<A, bool>?` nor `Func?<A, bool>` is working.