Better error for import of associated items

[ijackson]

Hi. I was using a crate which had a struct with a number of associated items and I was trying to save typing in an error handling function. But:

12 |     use rocket::http::Status::*;
   |                       ^^^^^^ `Status` is a struct, not a module

I looked in the Reference and I wasn't able to find any discussion of this. In particular, I would expect it to be documented in the explanation of Use declarations under Items.

After considerably more digging, I found:

• associated constants can't be used #24915, a closed issue where the resolution was that this is not expected to work
• https://internals.rust-lang.org/t/importing-associated-constants/6610/5, a discussion about how to maybe implement this (although it seems unlikely that that approach could work for the glob import I was trying...)

It seems that this situation is likely to persist. Maybe the error message could be improved? Something like

hint: importing associated items is not supported; you must use a path from to the parent type each time

could help the user by letting them know they can't avoid the extra typing.

I will also file an issue against the Reference. Thanks for your attention.

[ijackson]

Sorry, but I can't see how to remove the bug tag. (This issue was originally going to be my bug report against the reference and somehow I accidentally submitted it while it was still half-finished.) Could someone fix that for me ?