[Mr_P]

Dependency injection systems (like Dagger or Guice) are essentially programming languages that specifically model this kind of initialization-vs-runtime distinction. Dagger is actually implemented as a compiler extension.

Singletons can be declared once, and then provided to various systems that need it, with read-only access.

In fact, they're more flexible than that: one can declare multiple nested "scopes" that each have their own initialization phase. For example, a web server could have one scope for process-wide singletons, and another for request-scoped "singletons".

The only thing missing is that these DI systems are for java, which doesn't have the const-correctness you'd ideally want. I'm not aware of any equivalent (and widely-used) systems for languages like c++ or Rust.

(Yes, I can feel hundreds of HN readers rolling their eyes as they read this, given the bad rep. DI systems have, but they're widely popular among FANG companies for a reason.)