C++ 不可移动不可复制对象向量的移动赋值不编译_C++_C++11_Visual Studio 2013_Language Lawyer_Move Semantics

C++ 不可移动不可复制对象向量的移动赋值不编译

c++ c++11 visual-studio-2013

C++ 不可移动不可复制对象向量的移动赋值不编译,c++,c++11,visual-studio-2013,language-lawyer,move-semantics,C++,C++11,Visual Studio 2013,Language Lawyer,Move Semantics,以下代码不使用Visual Studio 2013编译： #include <vector> struct X { X() = default; X(const X&) = delete; X& operator=(const X&) = delete; X(X&&) = delete; X& operator=(X&&) = delete; ~X() = default

以下代码不使用Visual Studio 2013编译：

#include <vector>

struct X {
    X() = default;
    X(const X&) = delete;
    X& operator=(const X&) = delete;
    X(X&&) = delete;
    X& operator=(X&&) = delete;
    ~X() = default;
};

void foo()
{
    std::vector<X> v;
    std::vector<X> w;
    w = std::move(v);
}

那对我来说毫无意义。移动

向量

不需要

的移动构造函数。这是一个编译器错误，还是我遗漏了什么

以下是完整的错误消息：

C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(600): error C2280: 'X::X(X &&)' : attempting to reference a deleted function
    Test.cpp(9) : see declaration of 'X::X'
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(723) : see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,_Ty>(_Objty *,_Ty &&)' being compiled
    with
    [
        _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(723) : see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,_Ty>(_Objty *,_Ty &&)' being compiled
    with
    [
        _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(872) : see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,_Ty>(std::allocator<_Ty> &,_Objty *,_Ty &&)' being compiled
    with
    [
        _Alloc=std::allocator<X>
    ,   _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(872) : see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,_Ty>(std::allocator<_Ty> &,_Objty *,_Ty &&)' being compiled
    with
    [
        _Alloc=std::allocator<X>
    ,   _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(378) : see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<X,X>(_Ty *,X &&)' being compiled
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(378) : see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<X,X>(_Ty *,X &&)' being compiled
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(416) : see reference to function template instantiation '_FwdIt std::_Uninit_copy<_InIt,_FwdIt,std::allocator<_Ty>>(_InIt,_InIt,_FwdIt,std::_Wrap_alloc<std::allocator<_Ty>> &,std::_Nonscalar_ptr_iterator_tag)' being compiled
    with
    [
        _FwdIt=X *
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(427) : see reference to function template instantiation '_FwdIt std::_Uninit_copy<_Iter,X,_Alloc>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
    with
    [
        _FwdIt=X *
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Alloc=std::_Wrap_alloc<std::allocator<X>>
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(1640) : see reference to function template instantiation '_FwdIt std::_Uninitialized_copy<_Iter,X*,std::_Wrap_alloc<std::allocator<_Ty>>>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
    with
    [
        _FwdIt=X *
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Ty=X
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Alloc=std::_Wrap_alloc<std::allocator<X>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(789) : see reference to function template instantiation 'X *std::vector<X,std::allocator<_Ty>>::_Ucopy<_Iter>(_Iter,_Iter,X *)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(789) : see reference to function template instantiation 'X *std::vector<X,std::allocator<_Ty>>::_Ucopy<_Iter>(_Iter,_Iter,X *)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(766) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<_Iter>(_Iter,_Iter,std::forward_iterator_tag)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(766) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<_Iter>(_Iter,_Iter,std::forward_iterator_tag)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(854) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>>(_Iter,_Iter)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(854) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>>(_Iter,_Iter)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(849) : while compiling class template member function 'void std::vector<X,std::allocator<_Ty>>::_Assign_rv(std::vector<_Ty,std::allocator<_Ty>> &&,std::false_type)'
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(860) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Assign_rv(std::vector<_Ty,std::allocator<_Ty>> &&,std::false_type)' being compiled
    with
    [
        _Ty=X
    ]
    Test.cpp(16) : see reference to class template instantiation 'std::vector<X,std::allocator<_Ty>>' being compiled
    with
    [
        _Ty=X
    ]

C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory0（600）：错误C2280:'X:：X（X&&）'：尝试引用已删除的函数
Test.cpp（9）：参见“X:：X”的声明
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory0（723）：请参阅正在编译的函数模板实例化“void std:：allocator:：construct（_Objty*，_Ty&）”
具有
[
_Ty=X
，_Objty=X
]
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory0（723）：请参阅正在编译的函数模板实例化“void std:：allocator:：construct（_Objty*，_Ty&）”
具有
[
_Ty=X
，_Objty=X
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory0（872）：请参阅正在编译的函数模板实例化“void std:：allocator_traits:：construct（std:：allocator&、_Objty*、_Ty&）”的参考
具有
[
_Alloc=std:：分配器
，_Ty=X
，_Objty=X
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory0（872）：请参阅正在编译的函数模板实例化“void std:：allocator_traits:：construct（std:：allocator&、_Objty*、_Ty&）”的参考
具有
[
_Alloc=std:：分配器
，_Ty=X
，_Objty=X
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory（378）：请参阅正在编译的函数模板实例化“void std:：_Wrap\u alloc:：construct（_Ty*，X&）”的参考
具有
[
_Ty=X
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory（378）：请参阅正在编译的函数模板实例化“void std:：_Wrap\u alloc:：construct（_Ty*，X&）”的参考
具有
[
_Ty=X
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory（416）：请参阅正在编译的函数模板实例化“\u FwdIt std:\u Uninit\u copy（\u InIt，\u InIt，\u FwdIt，std:\u Wrap\u alloc&，std:\u Nonscalar\u ptr\u iterator\u tag）”
具有
[
_FwdIt=X*
，_InIt=std:：move_迭代器
，_Ty=X
]
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\xmemory（427）：请参阅正在编译的函数模板实例化“\u FwdIt std:：\u Uninit\u copy（\u InIt，\u FwdIt，\u Alloc&）”的参考
具有
[
_FwdIt=X*
，Iter=std:：move\u迭代器
，_Alloc=std:：_Wrap_Alloc
，_InIt=std:：move_迭代器
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（1640）：请参阅正在编译的函数模板实例化“\u FwdIt std:：\u未初始化的\u副本（\u InIt，\u FwdIt，\u Alloc&）”
具有
[
_FwdIt=X*
，Iter=std:：move\u迭代器
，_Ty=X
，_InIt=std:：move_迭代器
，_Alloc=std:：_Wrap_Alloc
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（789）：请参阅正在编译的函数模板实例化“X*std:：vector:：\u uUCopy（\u Iter，\u Iter，X*）”
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（789）：请参阅正在编译的函数模板实例化“X*std:：vector:：\u uUCopy（\u Iter，\u Iter，X*）”
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\vector（766）：请参阅正在编译的函数模板实例化“void std:：vector:：：_Construct（_Iter，_Iter，std:：forward_iterator_tag）”
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\vector（766）：请参阅正在编译的函数模板实例化“void std:：vector:：：_Construct（_Iter，_Iter，std:：forward_iterator_tag）”
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（854）：请参阅正在编译的函数模板实例化“void std:：vector:：_Construct（_Iter，_Iter）”的参考
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（854）：请参阅正在编译的函数模板实例化“void std:：vector:：_Construct（_Iter，_Iter）”的参考
具有
[
_Ty=X
，Iter=std:：move\u迭代器
]
C:\ProgramFiles（x86）\Microsoft Visual Studio 12.0\VC\include\vector（849）：编译类模板成员函数“void std:：vector:：_Assign_rv（std:：vector&，std:：false_type）”时
具有
[
_Ty=X
]
C:\Program Files（x86）\Microsoft Visual Studio 12.0\VC\include\vector（860）：请参阅正在编译的函数模板实例化“void std:：vector:：_Assign_rv（std:：vector&，std:：false_type）”的参考
具有
[
_Ty=X
]
cpp（16）：请参阅对正在编译的类模板实例化“std:：vector”的引用
具有
[
_Ty=X
]

C++11的答案： VS符合原始规范，因为根据缺陷报告，

std:：allocator的规范
导致对具有默认分配器的容器的移动分配运算符产生不必要的要求（MoveInsertable
和MoveAssignable
）
然而，这在C++14中是固定的。因此，现在std:：allocator
不再使此代码非法，根据N3797中的表96（[20.2.1，container.requirements.general]），对std:：vector=：X的模板参数T
的要求是
C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(600): error C2280: 'X::X(X &&)' : attempting to reference a deleted function
    Test.cpp(9) : see declaration of 'X::X'
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(723) : see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,_Ty>(_Objty *,_Ty &&)' being compiled
    with
    [
        _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(723) : see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,_Ty>(_Objty *,_Ty &&)' being compiled
    with
    [
        _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(872) : see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,_Ty>(std::allocator<_Ty> &,_Objty *,_Ty &&)' being compiled
    with
    [
        _Alloc=std::allocator<X>
    ,   _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory0(872) : see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,_Ty>(std::allocator<_Ty> &,_Objty *,_Ty &&)' being compiled
    with
    [
        _Alloc=std::allocator<X>
    ,   _Ty=X
    ,   _Objty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(378) : see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<X,X>(_Ty *,X &&)' being compiled
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(378) : see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<X,X>(_Ty *,X &&)' being compiled
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(416) : see reference to function template instantiation '_FwdIt std::_Uninit_copy<_InIt,_FwdIt,std::allocator<_Ty>>(_InIt,_InIt,_FwdIt,std::_Wrap_alloc<std::allocator<_Ty>> &,std::_Nonscalar_ptr_iterator_tag)' being compiled
    with
    [
        _FwdIt=X *
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\xmemory(427) : see reference to function template instantiation '_FwdIt std::_Uninit_copy<_Iter,X,_Alloc>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
    with
    [
        _FwdIt=X *
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Alloc=std::_Wrap_alloc<std::allocator<X>>
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(1640) : see reference to function template instantiation '_FwdIt std::_Uninitialized_copy<_Iter,X*,std::_Wrap_alloc<std::allocator<_Ty>>>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
    with
    [
        _FwdIt=X *
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Ty=X
    ,   _InIt=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ,   _Alloc=std::_Wrap_alloc<std::allocator<X>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(789) : see reference to function template instantiation 'X *std::vector<X,std::allocator<_Ty>>::_Ucopy<_Iter>(_Iter,_Iter,X *)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(789) : see reference to function template instantiation 'X *std::vector<X,std::allocator<_Ty>>::_Ucopy<_Iter>(_Iter,_Iter,X *)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(766) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<_Iter>(_Iter,_Iter,std::forward_iterator_tag)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(766) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<_Iter>(_Iter,_Iter,std::forward_iterator_tag)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(854) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>>(_Iter,_Iter)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(854) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Construct<std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>>(_Iter,_Iter)' being compiled
    with
    [
        _Ty=X
    ,   _Iter=std::move_iterator<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<X>>>>
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(849) : while compiling class template member function 'void std::vector<X,std::allocator<_Ty>>::_Assign_rv(std::vector<_Ty,std::allocator<_Ty>> &&,std::false_type)'
    with
    [
        _Ty=X
    ]
    C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\vector(860) : see reference to function template instantiation 'void std::vector<X,std::allocator<_Ty>>::_Assign_rv(std::vector<_Ty,std::allocator<_Ty>> &&,std::false_type)' being compiled
    with
    [
        _Ty=X
    ]
    Test.cpp(16) : see reference to class template instantiation 'std::vector<X,std::allocator<_Ty>>' being compiled
    with
    [
        _Ty=X
    ]

a = rv