private int CalculateHashCode(IEqualityComparer /*!*/ comparer)
{
Assert.NotNull(comparer);
HashCache curHashCache = _hashCache;
if (curHashCache != null && object.ReferenceEquals(comparer, curHashCache.Comparer))
{
return(curHashCache.HashCode);
}
int hash = SetStorage.GetHashCode(_items, comparer);
_hashCache = new HashCache(hash, comparer);
return(hash);
}
