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Showing content from https://en.cppreference.com/w/cpp/algorithm/../language/../types/is_move_constructible.html below:

std::is_move_constructible, std::is_trivially_move_constructible, std::is_nothrow_move_constructible - cppreference.com

template< class T > struct is_move_constructible;

(1) (since C++11)

template< class T > struct is_trivially_move_constructible;

(2) (since C++11)

template< class T > struct is_nothrow_move_constructible;

(3) (since C++11)

If T is not a complete type, (possibly cv-qualified) void, or an array of unknown bound, the behavior is undefined.

If an instantiation of a template above depends, directly or indirectly, on an incomplete type, and that instantiation could yield a different result if that type were hypothetically completed, the behavior is undefined.

If the program adds specializations for any of the templates described on this page, the behavior is undefined.

[edit] Helper variable templates template< class T > inline constexpr bool is_move_constructible_v = is_move_constructible<T>::value; (since C++17) template< class T > inline constexpr bool is_trivially_move_constructible_v = is_trivially_move_constructible<T>::value; (since C++17) template< class T > inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<T>::value; (since C++17) Inherited from std::integral_constant Member constants true if T is move-constructible, false otherwise
(public static member constant) Member functions converts the object to bool, returns value
(public member function) returns value
(public member function) Member types [edit] Possible implementation [edit] Notes

Types without a move constructor, but with a copy constructor that accepts const T& arguments, satisfy std::is_move_constructible.

Move constructors are usually noexcept, since otherwise they are unusable in any code that provides strong exception guarantee.

In many implementations, std::is_nothrow_move_constructible also checks if the destructor throws because it is effectively noexcept(T(arg)). Same applies to std::is_trivially_move_constructible, which, in these implementations, also requires that the destructor is trivial: GCC bug 51452, LWG issue 2116.

[edit] Example

#include <string>
#include <type_traits>
 
struct Ex1
{
    std::string str; // member has a non-trivial but non-throwing move constructor
};
static_assert(std::is_move_constructible_v<Ex1>);
static_assert(!std::is_trivially_move_constructible_v<Ex1>);
static_assert(std::is_nothrow_move_constructible_v<Ex1>);
 
struct Ex2
{
    int n;
    Ex2(Ex2&&) = default; // trivial and non-throwing
};
static_assert(std::is_move_constructible_v<Ex2>);
static_assert(std::is_trivially_move_constructible_v<Ex2>);
static_assert(std::is_nothrow_move_constructible_v<Ex2>);
 
struct NoMove1
{
    // prevents implicit declaration of default move constructor;
    // however, the class is still move-constructible because its
    // copy constructor can bind to an rvalue argument
    NoMove1(const NoMove1&) {}
};
static_assert(std::is_move_constructible_v<NoMove1>);
static_assert(!std::is_trivially_move_constructible_v<NoMove1>);
static_assert(!std::is_nothrow_move_constructible_v<NoMove1>);
 
struct NoMove2
{
    // Not move-constructible since the lvalue reference
    // can't bind to the rvalue argument
    NoMove2(NoMove2&) {}
};
static_assert(!std::is_move_constructible_v<NoMove2>);
static_assert(!std::is_trivially_move_constructible_v<NoMove2>);
static_assert(!std::is_nothrow_move_constructible_v<NoMove2>);
 
int main() {}

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior LWG 2196 C++11 the behavior was unclear if T&& cannot be formed the value produced is false in this case [edit] See also

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