Hiding those awful nested statements makes you think that perhaps the code is ok when it should probably be changed to make it more readable.
I don't think the example is all that good, because it's not the same code in both screenshots. The suggestion, as I read it, is that folding the "impl Body" shouldn't collapse the entire thing to impl Body { ... }, but instead collapse all the functions inside it, because that's actually more useful. So you'd get
impl Body {
fn new(db: &dyn DefDatabasse) { ... }
pub fn shrink_to_fit(&mut self) { ... }
}
It this was Python and you collapsed a class, then rather than getting class User(AbstractUser): ...
you'd get: class User(AbstractUser):
def is_manager(self): ...
def get_username(self): ...
It would perhaps even be a little neat if you could have a class collapsed and you'd be shown only public methods, if the language has the concept of public and private methods.To build on the "hiding awful code", I think this could help show awful API/interface design. If you have a class with a few hundred lines of code and a number of methods, then you rarely get to see all your methods listed, their signature just drowns in a sea of code. The also add doc strings, then you now have a documentation view of your own code in the IDE.