Question

在我需要的简短版本中，我的代码看起来像这样

#include <vector>

template<typename T>
class Abstract {
public:
    virtual void foo() = 0;
};

template<typename T>
class Collection {
public:
    std::vector<Abstract<T>> items;
};

class Some {};

class Implementor : public Abstract<Some> {
public:
    void foo() {
        //...
    }
};

int main() {
    Collection<Some> *collection = new Collection<Some>;
    Implementor *implementor = new Implementor;
    collection->items.push_back(*implementor);
    return 0;
}

编译器的判决是

抽象类类型'Abstract'的无效new-expression

错误全文：

In file included from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\mingw32\bits\c++allocator.h:33:0,
                 from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\allocator.h:46,
                 from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\vector:61,
                 from D:\CLionProjects\test1\main.cpp:1:
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\ext\new_allocator.h: In instantiation of 'void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = Abstract<Some>; _Args = {const Abstract<Some>&}; _Tp = Abstract<Some>]':
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\alloc_traits.h:455:4:   required from 'static void std::allocator_traits<std::allocator<_Tp1> >::construct(std::allocator_traits<std::allocator<_Tp1> >::allocator_type&, _Up*, _Args&& ...) [with _Up = Abstract<Some>; _Args = {const Abstract<Some>&}; _Tp = Abstract<Some>; std::allocator_traits<std::allocator<_Tp1> >::allocator_type = std::allocator<Abstract<Some> >]'
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\stl_vector.h:918:30:   required from 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = Abstract<Some>; _Alloc = std::allocator<Abstract<Some> >; std::vector<_Tp, _Alloc>::value_type = Abstract<Some>]'
D:\CLionProjects\test1\main.cpp:27:45:   required from here
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\ext\new_allocator.h:120:4: error: invalid new-expression of abstract class type 'Abstract<Some>'
  { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
D:\CLionProjects\test1\main.cpp:4:7: note:   because the following virtual functions are pure within 'Abstract<Some>':
 class Abstract {
       ^~~~~~~~
D:\CLionProjects\test1\main.cpp:6:18: note:     void Abstract<T>::foo() [with T = Some]
     virtual void foo() = 0;
                  ^~~

如何明确指定向量的类型？

错误：向量分配器中的抽象类类型的new-expression无效

0 个答案: