Prevent explicitly specifiying lifetime arguments to functions when the parameters are not visible in the type signature.

[addiesh]

This is meant to fix #154490:

trait Trait {
    type Assoc<'a>;
}

// zero explicit generic lifetimes
fn do_thing<T: Trait>(_: Option<<T as Trait>::Assoc<'_>>) -> &i32 {
    todo!()
}

fn foo<T: Trait>() {
    // Previously, this would NOT cause any errors.
    // this PR makes it error out.
    do_thing::<'static, T>(None);
}

This started as a larger PR (#160471) but these changes work on their own.
Eventually, that PR should introduce the same checks for late-bound lifetimes.

[rustbot]

HIR ty lowering was modified

cc @fmease

[rustbot]

Thanks for the pull request, and welcome! The Rust Project is excited to review your changes, and you should hear from @mejrs (or someone else) some time within the next two weeks.

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[mejrs]

Isn't this a breaking change?

[addiesh]

I don't think so? Afaik, the only way that this can happen is through a bug.

It may be worth a crater run to check to see if anyone is relying on this behavior though?

[mejrs]

Well, that depends on how breaking it is :)

[oli-obk]

@bors try

[rust-bors]

☀️ Try build successful (CI)
Build commit: 36e0a7e (36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6)
Base parent: 22950ab (22950ab9e29e11620a10905f027f141ea126966e)

[oli-obk]

@craterbot check

[craterbot]

👌 Experiment pr-160581 created and queued.
🤖 Automatically detected try build 36e0a7e
🔍 You can check out the queue and this experiment's details.

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