let mut jim: Goat;
// Potentially much later ...
if some_reason {
jim = make_a_new_goat();
} else {
jim = get_existing_goat();
}
use(jim); // In some way we use that goat now
But, if we screw up and make it unclear whether jim is initialized, probably because in some cases it wouldn't be - that doesn't compile.
This is the usual "avoid early initialization" C++ programmers are often thinking of and it doesn't need MaybeUninit, since it's definitely fine if you're correct, it's just that the C++ compiler is happy (before C++ 26) with just having Undefined Behaviour if you make any mistakes and the Rust compiler will reject that.
[Idiomatically this isn't good Rust, Rust is an expression language so we can just write all that conditional if-else block in the initializer itself and that's nicer, but if you're new to this the above works fine.]
That's great. You can get that check on C++ projects by flipping a compiler flag.
Aren't we discussing C++?
Your knowledge doesn't seem to even reach the point of having googled the topic. If you googled it once, you'd not be commenting it doesn't exist. Hell, you don't even seem to have read the thread, let alone the discussion.
(Safe) Rust does guarantee to identify uninitialised variable reads, but I believe the point is that you can get the optimisation of not forcing early initialisation in Rust, you just have to be explicit that that's what you want (you use the MaybeUninit type); you're forced to be clear that that's what you meant, not just by forgetting parens.