alt Hacker News> > Only (possibly cv-qualified) non-POD class types (or arrays thereof) with automatic storage duration were considered to be default-initialized when no initializer is used. Each direct non-variant non-static data member M of T has a default member initializer or, if M is of class type X (or array thereof), X is const-default-constructible, if T is a union with at least one non-static data member, exactly one variant member has a default member initializer, if T is not a union, for each anonymous union member with at least one non-static data member (if any), exactly one non-static data member has a default member initializer, and each potentially constructed base class of T is const-default-constructible.
That's just a list of very simple rules for each kind of type. As a C++-phob person, C++ has a lot of footguns, but this isn't one of them.
This was a random snippet of complicated rules to illustrate what I mean. C++ has significant footguns and complexity when it comes to initialising an object. Even sticking by "Effective Modern C++" rules is a significant cognitive burden on something that should be simple and straightforward. Rust has (mostly) no such footguns; its complexity follows from the essential complexity of the problems at hand.