It seems that a vector will check if the move constructor is labeled as noexcept before deciding on whether to move or copy elements when reallocating. Is the default move constructor defined as noexcept? I saw the following documentation but it didn't specify this.http://en.cppreference.com/w/cpp/language/move_constructor
See Question&Answers more detail:osImplicitly-declared move constructor
If no user-defined move constructors are provided for a class type (struct, class, or union), and all of the following is true: there are no user-declared copy constructors there are no user-declared copy assignment operators there are no user-declared move assignment operators there are no user-declared destructors the implicitly-declared move constructor is not defined as deleted due to conditions detailed in the next section then the compiler will declare a move constructor as an inline public member of its class with the signature T::T(T&&) A class can have multiple move constructors, e.g. both T::T(const T&&) and T::T(T&&). If some user-defined move constructors are present, the user may still force the generation of the implicitly declared move constructor with the keyword default.