While the summary + interview The Register did was decent, when you read the actual paper, the proposal is way more interesting.

Not a fan of mut instead of just plain mutable, though.

Also I sure hope the compiler messages for this feature won’t be like the circle examples in the proposal in the end.

My understanding of Linux programming is that it’s mostly done in a code editor, then compiled on the command line.

That’s not really true. You can do that, but with most IDEs (and some text editors) you really don’t need to do that. You can do everything from the IDE.

I’m aware that cmake exists, and I’ve used it a bit, but I don’t like it. VS lets me just drop a .h and .cpp file into the solution explorer and I’m good-to-go. Is there really no graphical alternative for Linux?

It depends on the IDE and how it handles project files. Nowadays Qt Creator for example can just create your source code files and automatically add them to the generated project CMake. I’m pretty sure other IDEs or text editors have this functionality when paired with CMake or Meson too.

It must be noted that if the IDE has some custom project file manager (like Visual Studio does with sln and vcproj files) and you use it exclusively, you’ll likely restrict your project to one platform and one IDE. Using something like CMake or Meson will make it easier to do crossplatform development and will let your users build the project without needing that specific IDE.

Personally I like modern CMake, the problem is that you’ll see a lot of projects in the wild doing old CMake style, which is awful. Meson is okay, although it feels very Pythonic to me and lacks some features I use for Qt stuff.

I remember once researching when to use variant and any, and coming up with https://stackoverflow.com/questions/56303939/c-stdvariant-vs-stdany. The naïve summary being:

any is a dressed-up void*. variant is a dressed-up union.

So you’d use std::any for similar reasons to void* (that other commenters already mentioned) while getting some advantages. In that sense it’s kinda similar to using a std::span for pointer arithmetic instead of actual C-style pointer arithmetic, it makes a necessary evil safer to do.

can I write modern C++ code using the newer standards and still compile with libraries from older standards?

Yes, but then your project ends up requiring that newer standard as minimum too (which can be fine if that’s what you want).

how do I even organize a C++ project?

Well, one way that should be simple and scalable for beginners is leaving the root folder for project configuration/metadata/contribution guidelines/clang-format etc. and putting all source code inside src/.

If it’s just an app, you can make smaller library targets in src/ in separate folders with meaningful names, like src/models/, src/settings/ etc. If it’s a library, you typically put headers you intend to expose to your users in a src/include/ folder and use target_include_directories() to point to it, otherwise the same principle as apps applies.

It requires writing a few more, smaller CMakeLists, but it does mean you’re never lost in your own code.

how do I install dependencies?

We added this recently to KDE’s developer documentation, so at least for Linux it’s a start: Installing build dependencies: Using build errors to find missing dependencies.