Don't crash in item_path when an item lacks a name

[arielb1]

Fixes#34027

We may want to use a better name than <unnamed>, but I just cherry-picked my old commit.

r? @brson

[rust-highfive]

Warning

• Pull requests are usually filed against the master branch for this repo, but this one is against beta. Please double check that you specified the right target!

[alexcrichton]

Backport-wise the protocol is typically to send a PR to master, tag it beta-nominated, and then cherry-pick it backwards once it's landed. (just FYI).

Also just to clarify, this is a cherry-pick of f6068ea from #33622, right?

[arielb1]

@alexcrichton

This already landed in master as part of a larger PR, with the motivation of unbreaking logging so I could debug some issue, so I can't really open a new one. This is indeed an unmodified cherry-pick of f6068ea.

[alexcrichton]

Ok cool, sounds good to me!

[alexcrichton]

cc @rust-lang/compiler about backporting

[brson]

sgtm

[alexcrichton]

With a lack of r+, the fact that this is already on stable, and the fact that the stable 1.10 release is to be built tomorrow, this is relatively unlikely to be backported at this point. If it's critical to include, however, we can make it work.

[arielb1]

We want to include this - the regression is very annoying when it hits. Could @eddyb r+ this?

[arielb1]

This is indeed a regression to 1.9 (current stable). In that case, I don't think we should backport.

[alexcrichton]

Ok, removing the beta-nominated tag from this as well.