[randomdata]

> becomes the error returned by the entire function

If you find the error returned by f.Close to be significant, are you sure returning again it is the right course of action? Most likely you want to do something more meaningful with that state, like retrying the write with an alternate storage device.

Returning the error is giving up, and giving up just because a file didn't close does not make for a very robust system. Not all programs need to be robust, necessarily, but Go is definitely geared towards building systems that are intended to be robust.

[foldr]

It obviously depends on the context. There's no general right or wrong answer to that question.