You’re not stupid: the OP wrote a bunch of jargon that more or less nobody in the industry uses on any regular basis. It’s a similar pattern to functional progr

You’re not stupid: the OP wrote a bunch of jargon that more or less nobody in the industry uses on any regular basis. It’s a similar pattern to functional programming evangelists’ rhetoric. The short answer is this: the compiler enforces type-checked unions (called `enum` in Rust) guaranteed to hold one specific type, and requires any `match` block (cf `switch`) checking a value to exhaustively check all possible ones. That’s not the whole story, but it covers about 99.99% of the use cases the OP refers to.