Having made lint `ambiguous_glob_imports` deny-by-default and report-in-deps

[traviscross]

The following change to a lint level went in without our review:

• Make lint ambiguous_glob_imports deny-by-default and report-in-deps #143011

ambiguous_glob_imports

Are we retroactively OK with this?

cc @petrochenkov @rust-lang/lang @ehuss

[petrochenkov]

More than ok, this is one of the worst things that exist in rustc_resolve, and the sooner it turns into a hard error the better.

It's semi-blocking #145108 because the lint heuristics depend on import resolution order, and import resolution is supposed to be order-independent (which that PR tries to ensure).
The heuristics themselves (when it's a compatibility lint and not an error) are also pretty unexplainable, if you read the code they sort of look like nonsense, but by some miracle they largely matched the specific crater run results in <find PR> that they were supposed to address.

[nikomatsakis]

I'd have preferred to know about it ahead of time, but yes, this seems like a good change. 👍

[traviscross]

We talked about this in the lang call today. We like the change and retroactively accept it.

Please note, however, that all changes to lint levels, changes to whether a lint reports in deps, new lints, and material lint expansions require our review and FCP.

We're often willing be fairly aggressive about fixing bugs, so it's likely that it'll move faster with our help in any event.