Tidy headers

[esseivaju]

@sethrj That's what it takes to tidy the headers, 90% of it is just the rule of 5, missing std::forward on function objects passed as universal reference, and override/final annotations.

[github-actions]

Test summary

 3 882 files   5 991 suites   4m 12s ⏱️
 1 609 tests  1 580 ✅ 29 💤 0 ❌
19 907 runs  19 832 ✅ 75 💤 0 ❌

Results for commit 00ccf65.

♻️ This comment has been updated with latest results.

[sethrj]

@esseivaju This is great, but before you go any further can you turn off the "operator= signature" and "missing std::forward" since those are always going to generate new warnings for correct code?

[esseivaju]

@esseivaju This is great, but before you go any further can you turn off the "operator= signature" and "missing std::forward" since those are always going to generate new warnings for correct code?

I'll turn these off, out of curiosity, what's the advantage of passing a function object by forwarding reference instead of constructing referenced if we need to call it multiple times?

[sethrj]

@esseivaju The problem is that if you've got a functor that has a mutable operator() then you have to pass a mutable reference; but if you're passing a const function object then you have to use a const reference. Passing by value or rvalue reference is I think the only way to do it.

[sethrj]

Thanks for all that (hopefully not too tedious) work!