Miss Dada  🏳️‍⚧️

so how come rust can do this? what's in its type system that makes it ok

I don't think it can, can it? Do you have an example of this working?

yes, you can implement, say, Into<T> for multiple T on the same type, and then `let x: T = thing.into()` figures out which into() you meant

Oh, right, neat. Without knowing much about how this works (because I've just found out that it does), it's presumably because the resolution is more like a type class than dynamic dispatch, so has access to more than just the type of `thing` when resolving it.

yes, dispatch is statically decided

Yeah, I realise that, but it's more a case of which information is visible in dispatch. Dispatch is a mix of of statically and dynamically decided in Java, but the expected return type is not part of the available information (amusingly, it *is* at the bytecode level)

oh right, yes okay -- in rust, the expected return is part of the dispatch, like in haskell; `let x: T = thing.into()` desugars to `let x = Into<T>::into(thing)`

yeah, exactly.