Value semantics give you sensible behavior. Smart pointers should not appear in user-visible interfaces.
It is easy to tie yourself in knots by doing the complicated thing. The solution is to do the simple thing.
why? I personally love functions like `EResult function(const T1& inParam1, T2& outParam2)`. the function signature makes it obvious what the function does (or should do, at least) and it's easy to avoid accidental copying.
Besides being horrible style, operating on references cripples the optimizer. "Avoid accidental copying"? What good is that if it's slower than if you did the copy?
Sometimes an optional is better, such as when downstream already takes one.
Occasionally, checking whether the operation (and a bunch of others) would succeed is best, particularly in high-rel/high-av systems. There, you are probably also logging, first, what you are about to attempt.
Good advice. Corollary: don't use tools that make it hard to do simple things, or force you to live with the not-simple things others have done.
Rust has the advantage of fewer legacy choices thrust upon it, although it is rapidly building up its own legacy. It is thus far less expressive, so I cannot capture as much meaning in a library. It is less mature, limiting its practical usability. It has some complications C++ lacks, some of which are unavoidable even in little programs.
By the time Rust is mature, it (including its milieu) will be as complicated as C++ is today, with as many legacy boat anchors. But it will be as expressive and as practically useful, and I will have two choices of commensurate standing. For now, C++ is really all we have.
It all traces back to the destructor: the original innovation that makes the rest possible. Rust's Drop trait fills the identical role. Nothing else has it.
How do I deal with C++'s complexity? I stay the hell away from things that are too hard to understand. It's not hard. The most useful parts of the language are simple when used right.