anchor.diff:     * Create a [CompletionTarget] holding the given [containingNode] and
      * [entity].
      */
  -  CompletionTarget._(AstNode containingNode, Object entity, this.isCommentText)
  +  CompletionTarget._(
  +      this.unit, AstNode containingNode, Object entity, this.isCommentText)
         : this.containingNode = containingNode,
           this.entity = entity,
           this.argIndex = _computeArgIndex(containingNode, entity);
  
positive.code:  * Clients may not extend, implement or mix-in this class.
   */
  class CompletionTarget {
    /**
     * The context in which the completion is occurring.  This is the AST node
     * which is a direct parent of [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,
  