> How can any professional programmer be 180 degrees wrong about the purpose of a function they use regularly
If you have a strong understanding of move semantics, then I agree it would be pretty weird to misunderstand the relationship between move semantics and emplace_back. But how common is it to have a strong understanding of move semantics, really? Can we confidently assume that even 50% of professional C++ programmers have a strong understanding of move semantics? I've known competent C++ devs, who write template metaprograms for fun, who were still surprised to learn basic facts about move semantics like "the destructor of a moved-from object will still be called." I know for certain that I don't have a strong understanding of move semantics, but I wouldn't call myself a C++ programmer either, so at least I'm not dragging down the statistics :)
Yes, I think his recommendation to prefer push_back is wrong for that reason. I can't imagine it's easier for the compiler to reason about std::move and destructors compared to inlining the constructor.
Nope, he's right. He maybe shouldn't be right, but certain convenience features are still missing from Standard Library components and the language that could someday make him wrong.
It is sometimes right to hold your nose and use std::piecewise_construct.
But most usually it doesn't matter, and worrying about it will distract you from what does matter. So, push_back() unless you know you have a good reason not to. And, you might never encounter one.
Good C++ and naïve C++ are not so different. Both are much better than fake-smart C++.
If you have a strong understanding of move semantics, then I agree it would be pretty weird to misunderstand the relationship between move semantics and emplace_back. But how common is it to have a strong understanding of move semantics, really? Can we confidently assume that even 50% of professional C++ programmers have a strong understanding of move semantics? I've known competent C++ devs, who write template metaprograms for fun, who were still surprised to learn basic facts about move semantics like "the destructor of a moved-from object will still be called." I know for certain that I don't have a strong understanding of move semantics, but I wouldn't call myself a C++ programmer either, so at least I'm not dragging down the statistics :)