Respect renamed dependencies when resolving configured paths

[fyrsta7]

Clippy's shared path resolver indexed external crates by their canonical metadata names. This meant that a path configured with the source-visible name of a renamed Cargo dependency could not resolve, even though that was the only name available in the crate's source code.

This keeps canonical-name lookup intact and also indexes prelude-visible --extern aliases by matching their canonical source paths to loaded crates. A source-visible alias takes precedence if it collides with another crate's canonical name, matching how paths resolve in source code. The shared fix applies to disallowed-methods, disallowed-types, and other configuration features that use the same path resolver.

The UI-Cargo regression covers alias resolution, canonical-name compatibility, and a collision with another crate's canonical name.

Fixes #17585

changelog: [disallowed_methods, disallowed_types]: resolve configured paths through renamed Cargo dependencies

Testing

• TESTNAME=disallowed_paths_renamed_dependency cargo uitest
• cargo test
• cargo dev fmt --check

[rustbot]

Thanks for the pull request. A reviewer will take a look after it receives 2 community reviews.

In the meantime, we would highly appreciate if you could try to review any of PRs waiting on community reviews.

[CommanderStorm]

code wise LGTM.
I have one clairifiying question and a nit.

View changes since this review

[CommanderStorm]

nit:
the init is getting a bit long which makes it harder to reason about...
Please split out into a method, since this way we can also add a good place for an brief explaing comment (that you arlready wrote in the PR description)

[fyrsta7]

Good point. I've moved the initialization into a collect_crates_by_name helper and added a comment explaining that prelude-visible --extern aliases are matched to loaded crates by source path and take precedence over colliding canonical names.

[CommanderStorm]

I think there is something I don't understand/know, but I would have expected these comments to be required...
Are they not??

Suggested change

	renamed_dependency::forbidden_by_alias();
	renamed_dependency::forbidden_by_package_name();
	renamed_dependency::forbidden_by_alias(); //~ disallowed_methods
	renamed_dependency::forbidden_by_package_name(); //~ disallowed_methods

[fyrsta7]

Thanks for asking. This test uses the ui-cargo harness, which validates diagnostics through Cargo.stderr rather than compiletest's inline //~ annotations. I checked the existing ui-cargo tests and they follow the same snapshot-based pattern, so I kept both expected disallowed_methods diagnostics in Cargo.stderr.

[CommanderStorm]

this is nasty and evil !!!

(it is a good test though)