Explicit definition of all ctrs, operator= and dstrs

[NikitaNikolaenko]

To comply with the rule C.21 of C++ Core Guidelines:
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c21-if-you-define-or-delete-any-copy-move-or-destructor-function-define-or-delete-them-all

This should have the same behavior as our implicitly-generated version.

[CodingCanuck]

I'm going to remove myself from the reviewer list for this PR: the mechanics look good while skimming through the diffs, but IMHO this could use @benh 's eyes on what we intend to be copy/moveable vs. which constructors and assignment operators we want to delete.

[CodingCanuck]

Why are some copy / move operations noexcept and others are not? I'd expect noexcept use to be consistent here: please document.

Glancing at code snippets below, I'd expect us to use noexcept everywhere we can.

[NikitaNikolaenko]

I don't think we have noexcept on copy operations (unless I made a typo?).

https://clang.llvm.org/extra/clang-tidy/checks/performance/noexcept-move-constructor.html

[CodingCanuck]

I don't think we have noexcept on copy operations (unless I made a typo?).

Why don't we have noexcept on our copy operations? Can our copy operations throw exceptions in a way that our move operation can't?

If not, it seems like our copy operations should also be noexcept.

[CodingCanuck]

I'm going to remove myself from the reviewer list for this PR: the mechanics look good while skimming through the diffs, but IMHO this could use @benh 's eyes on what we intend to be copy/moveable vs. which constructors and assignment operators we want to delete.

Ooh, I don't know how to remove myself now that I've "left a review" :/ https://github.com/orgs/community/discussions/23054

If this is useful, here's a doc on how to dismiss PR reviews: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/dismissing-a-pull-request-review (this might be a note for myself if a re-review request comes up)

[NikitaNikolaenko]

IMHO this could use @benh 's eyes on what we intend to be copy/moveable vs. which constructors and assignment operators we want to delete

This is one of the reasons why this PR was created :D
We have quite a lot of implicitness in our code right now (which I personally don't like) and this PR makes everyone think about whether we need this or that.