Unnecessary null check in KeyedCollection<TKey, TItem>.Contains(TKey)

Question

Just found an unnecessary null check in KeyedCollection.Contains(TKey).

Appreciate it's only a very small optimization, but shouldn't thought this sort of inefficiency be picked up by an automated code analysis tool?

Here's the C# generated by reflector:

public bool Contains(TKey key)
{
 if (key == null)
 {
  ThrowHelper.ThrowArgumentNullException(ExceptionArgument.key);
 }
 if (this.dict != null)
 {
  return this.dict.ContainsKey(key);
 }
 if (key != null) // Not needed as key cannot be null
 {
  foreach (TItem local in base.Items)
  {
   if (this.comparer.Equals(this.GetKeyForItem(local), key))
   {
    return true;
   }
  }
 }
 return false;
}

Also, what's the best way of sending in a patch? ;-) Through the .net forums or ?

Answer 1

This will probably be optimized by the JIT anyway, so you don't really need to worry about it. Anyway, the cost of a null check is close to zero.

To report a bug, you can use the Microsoft Connect website. But I don't think they will fix it...