It works great. Also, note that f() doesn't care about the type of error returned by g(), and that it will be a compilation error if g()'s error type turns into something incompatible.

Sadly, there are proposals to add exceptions to rust, and it seems likely they will be accepted, breaking error handling semantics across the entire ecosystem (even in new code, since exceptions are too hard to use correctly).

You can – by making f accept g's return types, including the error. This is even being done in the Go standard library: https://pkg.go.dev/text/template#Must

In a better langage f would take a Result, and then it can manipulate that however it wants.

Obviously you can also plug in adapters if you need some other composition e.g. g().map(f), g().and_then(f), …