Nullable types, lifted operators and ReSharper

Recently I investigated why ReSharper marks some pieces of my project code as invalid however compiler does not throw any errors.

Finally I narrowed down the problem.

class Program
    {
        static void Main(string[] args)
        {
            int? i = 10;

            A a = i;
        }

        class A
        {
            A(int i)
            {
                Value = i;
            }

            public int Value { get; private set; }

            public static implicit operator A(int i)
            {
                return new A(i);
            }
       }
    }

ReSharper highlights an error on line 7. However as you can imagine on a runtime corresponding implicit operator is called.
I investigated this behaviour and found that actually it is according to the C# spec

Nullable conversions and lifted conversions permit predefined and user-defin ed conversions that operate on non-nullable value types also to be used with nullable forms of those types. Likewise, lifted operators permit predefined and user-defined operators that work for non-nullable value types also to work for nullable forms of those types.
For every predefined conversion from a non-nullable value type S to a non-nullable value type T , a predefined nullable conversion automatically exists from S? to T?. This nullable conversion is a null propagating form of the underlying conversion: It converts a null source value directly to a null target value, but otherwise performs the underlying non-nullable co nversion. Nullable conversions are furthermore provided from S to T? and from S? to T , the latter as an explicit conversion that throws an exception if the source value is null.

So finally I know that it is a ReSharper bug and I will report it on their bug-tracker system.

Potentially it is a good question for juniors on interviews :)

UPD: Raised bug on ReSharper bug tracker
http://youtrack.jetbrains.net/issue/RSRP-287221?projectKey=RSRP&query=lifted