Why is copy constructor called in call to std::vector::emplace_back()?

Question

It is my understanding that the purpose of std::vector::emplace_back() is specifically to avoid calling a copy constructor, and instead to cons

Answer 1

Visual Studio 2013 and earlier fails to write default move constructors for you. Add a simple explicit move constructor to stuff.

A push or emplace back can cause stuff to be moved if it needs to reallocate, which in your case copies, as stuff has no move.

It is a msvc bug.