I keep thinking about the parallels between type checkers and abstract interpretation.
E.g. abstract interpretation saying "this is one of two values, but I don't know which" feels very much like type checking a boolean.
Have any tools taken advantage of this?
Related Posts
Really cute approach to reporting type errors: when there's a type error, show an example of a runtime error that the type check has prevented!
Data-Driven Techniques for Type Error Diagnosis https://escholarship.org/uc/item/59s4h4pv
I'm designing a programming language and trying to decide the type of `let x = 1;`. Should it be Unit or Int?
Advantage of Int: really convenient when evaluating snippets in a REPL.
Advantage of Unit: It's much less confusing when type inference runs on an incomplete function.
Playing with optional type signatures in Python, I realise that the return type is the most important to me.
I'd much rather have a function with only a return type instead of a function with only parameter types. It's often quick to add too.