/// <summary>
 /// Constructs an instance of <c>PropertyExpressionPart</c>.
 /// </summary>
 /// <param name="nextPart">
 /// The next part in the chain of parts held in the <see cref="PropertyExpression"/>.
 /// </param>
 protected PropertyExpressionPart(PropertyExpressionPart nextPart)
 {
     _nextPart = nextPart;
     _object   = new WeakReference(null);
 }
 /// <summary>
 /// Constructs an instance of <c>PropertyExpressionPart</c>.
 /// </summary>
 /// <param name="nextPart">
 /// The next part in the chain of parts held in the <see cref="PropertyExpression"/>.
 /// </param>
 protected PropertyExpressionPart(PropertyExpressionPart nextPart)
 {
     _nextPart = nextPart;
     _object = new WeakReference(null);
 }