Addendum: in this case, the "CopyTo" method is an extension method, and

the first parameter (the "this" parameter) is annotated NotNull:

public static void CopyTo(NotNull this IEnumerable source, NotNull

T[] destination, int destIndex) { ... }

"Mike Strobel" <mike.strobel@gmail.com> wrote in message

news:hkf3h2$cbu$1@nntp-server.labs.intellij.net...

When switching value analysis mode to "pessimistic" (Build 1609), I get a

false warning with the following code:

>

internal sealed class IndexedEnumerableDebugView<T>

{

   private readonly IIndexedEnumerable<T> _collection;

>

   public IndexedEnumerableDebugView(IIndexedEnumerable<T> collection)

   {

       if (collection == null)

           throw new ArgumentNullException("collection");

       _collection = collection;

   }

>

   DebuggerBrowsable(DebuggerBrowsableState.RootHidden)

   public T[] Items

   {

       get

       {

           var items = new T[_collection.Count];

           // On the following line, R# incorrectly warns "_collection"

may be null.

           _collection.CopyTo(items, 0);

           return items;

       }

   }

}

>

Since "_collection" is a private readonly field in a sealed class, and

"Items" is not accessed before the field is assigned, the field cannot

possibly be null.  Further, a NullReferenceException would have already

been thrown by the previous statement when accessing "_collection.Count".