My only complaint with this excellent list is that it treats "generics" and "lifetimes" as separate things. There's a reason the lifetime is inside the generic brackets. The code is generic over some lifetimes just as it can be generic over some types.

As a Rust beginner I read lifetimes backwards, thinking <'a> means I'm "declaring a lifetime" which I then use. What that actually declares is a placeholder for a lifetime the compiler will attempt to find wherever that struct or function is used, just as it would attempt to find a valid type for a type generic <T> at the points of usage.

Once I fixed that misconception everything made much more sense. Reminding myself that only the function signature matters, not the actual code, was the other thing I needed to really internalize.

The compiler messages hinder this sometimes, as when the compiler says "X doesn't live long enough" it actually means "using my limited and ever-evolving ability to infer possible lifetimes from your code, I can't find one that I can use here".

This is also (for me, anyway) a common "it's fine but it won't compile" case, where you don't have enough lifetime parameters. In other words, you're accidentally giving two things the same lifetime parameter when it's not actually necessary to require that the compiler come up with a single lifetime that works for both. The compiler error for that does not typically lead you to a solution directly.