anchor.diff:  
         // Since no completion target was found, we set the completion target
         // entity to null and use the compilationUnit as the parent.
  -      return new CompletionTarget._(compilationUnit, null, false);
  +      return new CompletionTarget._(
  +          compilationUnit, compilationUnit, null, false);
       }
     }
   
  
positive.code:    * Create a [CompletionTarget] holding the given [containingNode] and
     * [entity].
     */
    CompletionTarget._(AstNode containingNode, Object entity, this.isCommentText)
        : this.containingNode = containingNode,
          this.entity = entity,
          this.argIndex = _computeArgIndex(containingNode, entity);
  
negative.code:                 containingNode = docComment;
                } else {
                  return new CompletionTarget._(
                      compilationUnit, compilationUnit, commentToken, true);
                }
              }
              return new CompletionTarget._(
                  compilationUnit, containingNode, entity, false);
            }
  
            // Otherwise, the completion target is somewhere inside the entity,
  