I don't use D but think that error handling is one major feature:

https://dlang.org/articles/exception-safe.html

In concrete, looks to me to be the only language that covers the major ways to do it.

(In concrete the `scope` way is the one I found inspiring. . I think the exceptions can go and be replace by it for langs where exceptions are removed)

`scope` is very good at its job. It guarantees that a pointer passed as an argument does not escape the caller's scope. I find it almost as useful as transitive `const`.