Filter out RPITITs when checking for missing associated types

[spastorino]

This goes on top of other already approved PRs not merged yet. Going to rebase when they are merged. The only useful commit is the last one faa15d2

r? @compiler-errors

The included test is a copy of tests/ui/impl-trait/in-trait/issue-102140.rs which fails with the -Zlower-impl-trait-in-trait-to-assoc-ty currently.

Current master does the following ...

error[E0191]: the value of the associated type `` (from trait `MyTrait`) must be specified
  --> tests/ui/impl-trait/in-trait/new-lowering-strategy/trait-object-impl-trait.rs:23:10
   |
10 |     fn foo(&self) -> impl Marker
   |                      ----------- `` defined here
...
23 | impl dyn MyTrait {
   |          ^^^^^^^ help: specify the associated type: `MyTrait< = Type>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0191`.

And this PR behaves correctly, same output as current RPITIT code ...

gh-spastorino@dev-desktop-us-1:~/rust4$ rustc +rust4-stage1 tests/ui/impl-trait/in-trait/new-lowering-strategy/trait-object-impl-trait.rs
error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
  --> tests/ui/impl-trait/in-trait/new-lowering-strategy/trait-object-impl-trait.rs:23:22
   |
23 |         MyTrait::foo(&self)
   |         ------------ ^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
   |         |
   |         required by a bound introduced by this call
   |
help: consider removing the leading `&`-reference
   |
23 -         MyTrait::foo(&self)
23 +         MyTrait::foo(self)
   |

error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
  --> tests/ui/impl-trait/in-trait/new-lowering-strategy/trait-object-impl-trait.rs:23:9
   |
23 |         MyTrait::foo(&self)
   |         ^^^^^^^^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
   |
   = help: the trait `MyTrait` is implemented for `Outer`

error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
  --> tests/ui/impl-trait/in-trait/new-lowering-strategy/trait-object-impl-trait.rs:23:9
   |
23 |         MyTrait::foo(&self)
   |         ^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
   |
   = help: the trait `MyTrait` is implemented for `Outer`

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0277`.

[spastorino]

Added another commit ef950b8

That commit included test is a copy of tests/ui/async-await/in-trait/object-safety.rs which fails with the -Zlower-impl-trait-in-trait-to-assoc-ty currently.

Current master does the following ...

warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
 --> tests/ui/async-await/in-trait/object-safety.rs:3:12
  |
3 | #![feature(async_fn_in_trait)]
  |            ^^^^^^^^^^^^^^^^^
  |
  = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0038]: the trait `Foo` cannot be made into an object
  --> tests/ui/async-await/in-trait/object-safety.rs:11:12
   |
11 |     let x: &dyn Foo = todo!();
   |            ^^^^^^^^ `Foo` cannot be made into an object
   |
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
  --> tests/ui/async-await/in-trait/object-safety.rs:7:14
   |
6  | trait Foo {
   |       --- this trait cannot be made into an object...
7  |     async fn foo(&self);
   |              ^^^       ^ ...because it contains the generic associated type ``
   |              |
   |              ...because method `foo` is `async`
   = help: consider moving `foo` to another trait
   = help: consider moving `` to another trait

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0038`.

And this PR behaves correctly, same output as current RPITIT code ...

warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
 --> tests/ui/async-await/in-trait/object-safety.rs:3:12
  |
3 | #![feature(async_fn_in_trait)]
  |            ^^^^^^^^^^^^^^^^^
  |
  = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0038]: the trait `Foo` cannot be made into an object
  --> tests/ui/async-await/in-trait/object-safety.rs:11:12
   |
11 |     let x: &dyn Foo = todo!();
   |            ^^^^^^^^ `Foo` cannot be made into an object
   |
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
  --> tests/ui/async-await/in-trait/object-safety.rs:7:14
   |
6  | trait Foo {
   |       --- this trait cannot be made into an object...
7  |     async fn foo(&self);
   |              ^^^ ...because method `foo` is `async`
   = help: consider moving `foo` to another trait

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0038`.

[compiler-errors]

https://github.com/rust-lang/rust/blob/171aa24e8faeca0bb0a478f32f84b032c1fdda37/tests/ui/impl-trait/in-trait/object-safety.rs

This test needs a revision.

[spastorino]

https://github.com/rust-lang/rust/blob/171aa24e8faeca0bb0a478f32f84b032c1fdda37/tests/ui/impl-trait/in-trait/object-safety.rs

This test needs a revision.

I didn't properly investigate this test but it still not working even with this 2 commits. So I'd leave it for a followup.

[spastorino]

Getting thread 'rustc' panicked at 'called Option::unwrap()on aNone value', compiler/rustc_middle/src/ty/context.rs:2436:55 from CI. For tests/ui/impl-trait/in-trait/issue-102140.rs#next which is weird to me given that I was able to bless it locally https://github.com/rust-lang/rust/pull/108869/files#diff-66bc1ebad57c8b27e859819ec19c1c7a319b2d02c796bfb0864fa62ff2fd1ca3

[compiler-errors]

Possibly debug assertions. Drop the impl trait test and just do the async test, squash, then r=me.

[spastorino]

Possibly debug assertions. Drop the impl trait test and just do the async test, squash, then r=me.

Ohh, this is likely due to something that is already fixed in #108700. Maybe it's better if we wait for it?.

[compiler-errors]

Up to you.

[spastorino]

I'll wait for it, rebase and r=you if that's fine after I see everything green.

[compiler-errors]

yeah, either do what I said in #108869 (comment), or rebase + bless. r=me in that case, as long as the test stderrs are equal with/without the -Z flag (and also please check if the impl-trait/in-trait/object-safety.rs test passes). If the stderr has changed, re-request review from me or ping me or something.

[spastorino]

Placing it again on top of existing unmerged PRs, to see if CI is happy.

[spastorino]

@compiler-errors, this one is ready, rebased and ready for a final review.

[compiler-errors]

closed this one since you said you just wanted to land the other pr together as one stack