Add new lint shadow_type_generic

[devodev]

Add a new restriction lint shadow_type_generic that checks for generic parameters that shadow types in scope.

Closes: #380

changelog: [shadow_type_generic]: new lint

Summary Notes

• Feature freeze by samueltardieu

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[rustbot]

r? @dswij

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They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

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[dswij]

r? clippy

[samueltardieu]

Dear contributor. Clippy has entered a feature freeze period and will not be integrating new lints for a few weeks. You can rest assured that the Clippy team will review and discuss your proposal at the end of the feature freeze period.

If you wish to contribute to Clippy in the meantime, do not hesitate to read the pinned tracking issue about the feature freeze itself.

@rustbot label +A-lint +S-blocked -S-waiting-on-review
@rustbot note "Feature freeze"

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[flip1995]

r? clippy

I just saw that this PR is active again. Re-assigning, as I don't have review capacity at the moment. (I wonder why r? clippy picks me for reviews in the first place, as I'm not in the general rotation, only for some specific files 🤔 )