如何从模板化类方法返回依赖类型？

Question

假设我有一个基于模板的类ThingType.在标题中,我将其用于typedef依赖类型VectorThingType.我想从一个方法中返回这个GetVectorOfThings().如果我设置VectorThingType为返回类型,则会出现Does not name a type错误,因为此范围中未定义类型.有没有办法在不重复代码的情况下执行此操作typedef？

#include <vector>
#include <iostream>

template< typename ThingType >
class Thing
{
public:

 ThingType aThing;
 typedef std::vector< ThingType > VectorThingType;
 VectorThingType GetVectorOfThings();

Thing(){};
~Thing(){};

};

template< typename ThingType >
//VectorThingType // Does not name a type 
std::vector< ThingType > // Duplication of code from typedef
Thing< ThingType >
::GetVectorOfThings() {
  VectorThingType v;
  v.push_back(this->aThing);
  v.push_back(this->aThing);
  return v;
}

Answer 1

template< typename ThingType >
auto // <-- defer description of type until...
Thing< ThingType >
::GetVectorOfThings()
-> VectorThingType // <-- we are now in the context of Thing< ThingType >
{
  VectorThingType v;
  v.push_back(this->aThing);
  v.push_back(this->aThing);
  return v;
}