Merging upstream version 1.70.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

96 files changed, 698 insertions, 193 deletions

diff --git a/tests/ui/impl-trait/associated-impl-trait-type-generic-trait.rs b/tests/ui/impl-trait/associated-impl-trait-type-generic-trait.rs
index 6c7c46b0e..0908a0bf3 100644
--- a/tests/ui/impl-trait/associated-impl-trait-type-generic-trait.rs
+++ b/tests/ui/impl-trait/associated-impl-trait-type-generic-trait.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 // build-pass (FIXME(62277): could be check-pass?)
 
 trait Bar {}
diff --git a/tests/ui/impl-trait/associated-impl-trait-type-trivial.rs b/tests/ui/impl-trait/associated-impl-trait-type-trivial.rs
index cdda341ca..b5ea90bb0 100644
--- a/tests/ui/impl-trait/associated-impl-trait-type-trivial.rs
+++ b/tests/ui/impl-trait/associated-impl-trait-type-trivial.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 // build-pass (FIXME(62277): could be check-pass?)
 
 trait Bar {}
diff --git a/tests/ui/impl-trait/associated-impl-trait-type.rs b/tests/ui/impl-trait/associated-impl-trait-type.rs
index d0661d66f..f5981261c 100644
--- a/tests/ui/impl-trait/associated-impl-trait-type.rs
+++ b/tests/ui/impl-trait/associated-impl-trait-type.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 // build-pass (FIXME(62277): could be check-pass?)
 
 trait Bar {}
diff --git a/tests/ui/impl-trait/auto-trait-leak.stderr b/tests/ui/impl-trait/auto-trait-leak.stderr
index fd0358421..e6c750d0e 100644
--- a/tests/ui/impl-trait/auto-trait-leak.stderr
+++ b/tests/ui/impl-trait/auto-trait-leak.stderr
@@ -29,6 +29,11 @@ note: ...which requires building MIR for `cycle1`...
    |
 LL | fn cycle1() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which requires match-checking `cycle1`...
+  --> $DIR/auto-trait-leak.rs:12:1
+   |
+LL | fn cycle1() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires building THIR for `cycle1`...
   --> $DIR/auto-trait-leak.rs:12:1
    |
@@ -70,6 +75,11 @@ note: ...which requires building MIR for `cycle2`...
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which requires match-checking `cycle2`...
+  --> $DIR/auto-trait-leak.rs:19:1
+   |
+LL | fn cycle2() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires building THIR for `cycle2`...
   --> $DIR/auto-trait-leak.rs:19:1
    |
diff --git a/tests/ui/impl-trait/impl-fn-hrtb-bounds-2.stderr b/tests/ui/impl-trait/impl-fn-hrtb-bounds-2.stderr
index d56e1273f..835f7f765 100644
--- a/tests/ui/impl-trait/impl-fn-hrtb-bounds-2.stderr
+++ b/tests/ui/impl-trait/impl-fn-hrtb-bounds-2.stderr
@@ -6,7 +6,7 @@ LL | fn a() -> impl Fn(&u8) -> impl Debug {
 LL |     |x| x
    |     --- ^
    |     |
-   |     hidden type `&u8` captures the anonymous lifetime #1 defined here
+   |     hidden type `&u8` captures the anonymous lifetime as defined here
 
 error: aborting due to previous error
 
diff --git a/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs b/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
index 74df300f8..ffeabe5c2 100644
--- a/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
@@ -1,11 +1,14 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+
 #![feature(return_position_impl_trait_in_trait)]
 
+use std::ops::Deref;
+
 pub trait Foo {
-    fn bar() -> impl Sized;
+    fn bar() -> impl Deref<Target = impl Sized>;
 }
 
 pub struct Foreign;
-
 impl Foo for Foreign {
-    fn bar() {}
+    fn bar() -> &'static () { &() }
 }
diff --git a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.stderr b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.current.stderr
index d681ecf25..05c025cc1 100644
--- a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.stderr
+++ b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.current.stderr
@@ -1,5 +1,5 @@
 warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/box-coerce-span-in-default.rs:3:12
+  --> $DIR/box-coerce-span-in-default.rs:5:12
    |
 LL | #![feature(return_position_impl_trait_in_trait)]
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.next.stderr b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.next.stderr
new file mode 100644
index 000000000..05c025cc1
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.next.stderr
@@ -0,0 +1,11 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/box-coerce-span-in-default.rs:5:12
+   |
+LL | #![feature(return_position_impl_trait_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
index a4d483dee..163bb4fcf 100644
--- a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
+++ b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 //~^ WARN the feature `return_position_impl_trait_in_trait` is incomplete
diff --git a/tests/ui/impl-trait/in-trait/deep-match-works.rs b/tests/ui/impl-trait/in-trait/deep-match-works.rs
index 772da845e..5c9d2e356 100644
--- a/tests/ui/impl-trait/in-trait/deep-match-works.rs
+++ b/tests/ui/impl-trait/in-trait/deep-match-works.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
@@ -10,7 +12,9 @@ trait Foo {
 }
 
 impl Foo for () {
-    fn bar() -> Wrapper<i32> { Wrapper(0) }
+    fn bar() -> Wrapper<i32> {
+        Wrapper(0)
+    }
 }
 
 fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/deep-match.stderr b/tests/ui/impl-trait/in-trait/deep-match.current.stderr
index 3eba419c0..400db20c7 100644
--- a/tests/ui/impl-trait/in-trait/deep-match.stderr
+++ b/tests/ui/impl-trait/in-trait/deep-match.current.stderr
@@ -1,7 +1,7 @@
 error[E0053]: method `bar` has an incompatible return type for trait
-  --> $DIR/deep-match.rs:11:17
+  --> $DIR/deep-match.rs:14:17
    |
-LL |     fn bar() -> i32 { 0 }
+LL |     fn bar() -> i32 {
    |                 ^^^
    |                 |
    |                 expected `Wrapper<_>`, found `i32`
diff --git a/tests/ui/impl-trait/in-trait/deep-match.next.stderr b/tests/ui/impl-trait/in-trait/deep-match.next.stderr
new file mode 100644
index 000000000..400db20c7
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/deep-match.next.stderr
@@ -0,0 +1,15 @@
+error[E0053]: method `bar` has an incompatible return type for trait
+  --> $DIR/deep-match.rs:14:17
+   |
+LL |     fn bar() -> i32 {
+   |                 ^^^
+   |                 |
+   |                 expected `Wrapper<_>`, found `i32`
+   |                 return type in trait
+   |
+   = note: expected struct `Wrapper<_>`
+                found type `i32`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0053`.
diff --git a/tests/ui/impl-trait/in-trait/deep-match.rs b/tests/ui/impl-trait/in-trait/deep-match.rs
index a6385147c..413d054e1 100644
--- a/tests/ui/impl-trait/in-trait/deep-match.rs
+++ b/tests/ui/impl-trait/in-trait/deep-match.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
@@ -8,8 +11,10 @@ trait Foo {
 }
 
 impl Foo for () {
-    fn bar() -> i32 { 0 }
-    //~^ ERROR method `bar` has an incompatible return type for trait
+    fn bar() -> i32 {
+        //~^ ERROR method `bar` has an incompatible return type for trait
+        0
+    }
 }
 
 fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err-2.current.stderr
index cc3bdf0e5..85450e3b0 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err-2.current.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/default-body-type-err-2.rs:8:9
+  --> $DIR/default-body-type-err-2.rs:10:9
    |
 LL |         42
    |         ^^- help: try using a conversion method: `.to_string()`
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err-2.next.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err-2.next.stderr
new file mode 100644
index 000000000..85450e3b0
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err-2.next.stderr
@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/default-body-type-err-2.rs:10:9
+   |
+LL |         42
+   |         ^^- help: try using a conversion method: `.to_string()`
+   |         |
+   |         expected `String`, found integer
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs b/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
index 45ae2b8ad..623237763 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
@@ -1,4 +1,6 @@
 // edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![allow(incomplete_features)]
 #![feature(async_fn_in_trait)]
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err.current.stderr
index 4742eb37d..c949168a3 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err.stderr
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err.current.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<&i32 as Deref>::Target == String`
-  --> $DIR/default-body-type-err.rs:7:22
+  --> $DIR/default-body-type-err.rs:10:22
    |
 LL |     fn lol(&self) -> impl Deref<Target = String> {
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `String`
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err.next.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err.next.stderr
new file mode 100644
index 000000000..c949168a3
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err.next.stderr
@@ -0,0 +1,12 @@
+error[E0271]: type mismatch resolving `<&i32 as Deref>::Target == String`
+  --> $DIR/default-body-type-err.rs:10:22
+   |
+LL |     fn lol(&self) -> impl Deref<Target = String> {
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `String`
+LL |
+LL |         &1i32
+   |         ----- return type was inferred to be `&i32` here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0271`.
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err.rs b/tests/ui/impl-trait/in-trait/default-body-type-err.rs
index ac9baf91c..9bd5b7779 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![allow(incomplete_features)]
 #![feature(return_position_impl_trait_in_trait)]
 
diff --git a/tests/ui/impl-trait/in-trait/default-body-with-rpit.current.stderr b/tests/ui/impl-trait/in-trait/default-body-with-rpit.current.stderr
new file mode 100644
index 000000000..3c24eff9a
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-body-with-rpit.current.stderr
@@ -0,0 +1,24 @@
+error: concrete type differs from previous defining opaque type use
+  --> $DIR/default-body-with-rpit.rs:13:9
+   |
+LL |         ""
+   |         ^^ expected `impl Debug`, got `&'static str`
+   |
+note: previous use here
+  --> $DIR/default-body-with-rpit.rs:12:39
+   |
+LL |       async fn baz(&self) -> impl Debug {
+   |  _______________________________________^
+LL | |         ""
+LL | |     }
+   | |_____^
+
+error[E0720]: cannot resolve opaque type
+  --> $DIR/default-body-with-rpit.rs:12:28
+   |
+LL |     async fn baz(&self) -> impl Debug {
+   |                            ^^^^^^^^^^ cannot resolve opaque type
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0720`.
diff --git a/tests/ui/impl-trait/in-trait/default-body-with-rpit.next.stderr b/tests/ui/impl-trait/in-trait/default-body-with-rpit.next.stderr
new file mode 100644
index 000000000..3c24eff9a
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-body-with-rpit.next.stderr
@@ -0,0 +1,24 @@
+error: concrete type differs from previous defining opaque type use
+  --> $DIR/default-body-with-rpit.rs:13:9
+   |
+LL |         ""
+   |         ^^ expected `impl Debug`, got `&'static str`
+   |
+note: previous use here
+  --> $DIR/default-body-with-rpit.rs:12:39
+   |
+LL |       async fn baz(&self) -> impl Debug {
+   |  _______________________________________^
+LL | |         ""
+LL | |     }
+   | |_____^
+
+error[E0720]: cannot resolve opaque type
+  --> $DIR/default-body-with-rpit.rs:12:28
+   |
+LL |     async fn baz(&self) -> impl Debug {
+   |                            ^^^^^^^^^^ cannot resolve opaque type
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0720`.
diff --git a/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs b/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
index ad3cc7c25..6bcc7b9ef 100644
--- a/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
@@ -1,5 +1,7 @@
-// check-pass
 // edition:2021
+// known-bug: #108304
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/default-body.rs b/tests/ui/impl-trait/in-trait/default-body.rs
index b0baf5bb1..ab6a51c6b 100644
--- a/tests/ui/impl-trait/in-trait/default-body.rs
+++ b/tests/ui/impl-trait/in-trait/default-body.rs
@@ -1,5 +1,7 @@
 // check-pass
 // edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/default-method-binder-shifting.current.stderr b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.current.stderr
new file mode 100644
index 000000000..a0c0589b9
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.current.stderr
@@ -0,0 +1,11 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default-method-binder-shifting.rs:5:12
+   |
+LL | #![feature(return_position_impl_trait_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/impl-trait/in-trait/default-method-binder-shifting.next.stderr b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.next.stderr
new file mode 100644
index 000000000..a0c0589b9
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.next.stderr
@@ -0,0 +1,11 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default-method-binder-shifting.rs:5:12
+   |
+LL | #![feature(return_position_impl_trait_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs
new file mode 100644
index 000000000..de82544f2
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs
@@ -0,0 +1,22 @@
+// check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
+#![feature(return_position_impl_trait_in_trait)]
+//~^ WARN the feature `return_position_impl_trait_in_trait` is incomplete
+
+trait Trait {
+    type Type;
+
+    // Check that we're adjusting bound vars correctly when installing the default
+    // method projection assumptions.
+    fn method(&self) -> impl Trait<Type = impl Sized + '_>;
+}
+
+trait Trait2 {
+    type Type;
+
+    fn method(&self) -> impl Trait2<Type = impl Trait2<Type = impl Sized + '_> + '_>;
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/default-method-constraint.stderr b/tests/ui/impl-trait/in-trait/default-method-constraint.current.stderr
index 5e18605aa..7bb79911f 100644
--- a/tests/ui/impl-trait/in-trait/default-method-constraint.stderr
+++ b/tests/ui/impl-trait/in-trait/default-method-constraint.current.stderr
@@ -1,5 +1,5 @@
 warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/default-method-constraint.rs:5:12
+  --> $DIR/default-method-constraint.rs:7:12
    |
 LL | #![feature(return_position_impl_trait_in_trait)]
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/impl-trait/in-trait/default-method-constraint.next.stderr b/tests/ui/impl-trait/in-trait/default-method-constraint.next.stderr
new file mode 100644
index 000000000..7bb79911f
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/default-method-constraint.next.stderr
@@ -0,0 +1,11 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default-method-constraint.rs:7:12
+   |
+LL | #![feature(return_position_impl_trait_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/impl-trait/in-trait/default-method-constraint.rs b/tests/ui/impl-trait/in-trait/default-method-constraint.rs
index 8c50cc295..e85fe3c86 100644
--- a/tests/ui/impl-trait/in-trait/default-method-constraint.rs
+++ b/tests/ui/impl-trait/in-trait/default-method-constraint.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 // This didn't work in the previous default RPITIT method hack attempt
 
diff --git a/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr b/tests/ui/impl-trait/in-trait/doesnt-satisfy.current.stderr
index aa5492d28..653016cf0 100644
--- a/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr
+++ b/tests/ui/impl-trait/in-trait/doesnt-satisfy.current.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `()` doesn't implement `std::fmt::Display`
-  --> $DIR/doesnt-satisfy.rs:9:17
+  --> $DIR/doesnt-satisfy.rs:12:17
    |
 LL |     fn bar() -> () {}
    |                 ^^ `()` cannot be formatted with the default formatter
@@ -7,7 +7,7 @@ LL |     fn bar() -> () {}
    = help: the trait `std::fmt::Display` is not implemented for `()`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 note: required by a bound in `Foo::bar::{opaque#0}`
-  --> $DIR/doesnt-satisfy.rs:5:22
+  --> $DIR/doesnt-satisfy.rs:8:22
    |
 LL |     fn bar() -> impl std::fmt::Display;
    |                      ^^^^^^^^^^^^^^^^^ required by this bound in `Foo::bar::{opaque#0}`
diff --git a/tests/ui/impl-trait/in-trait/doesnt-satisfy.next.stderr b/tests/ui/impl-trait/in-trait/doesnt-satisfy.next.stderr
new file mode 100644
index 000000000..f0cd43bcf
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/doesnt-satisfy.next.stderr
@@ -0,0 +1,17 @@
+error[E0277]: `()` doesn't implement `std::fmt::Display`
+  --> $DIR/doesnt-satisfy.rs:12:17
+   |
+LL |     fn bar() -> () {}
+   |                 ^^ `()` cannot be formatted with the default formatter
+   |
+   = help: the trait `std::fmt::Display` is not implemented for `()`
+   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
+note: required by a bound in `Foo::{opaque#0}`
+  --> $DIR/doesnt-satisfy.rs:8:22
+   |
+LL |     fn bar() -> impl std::fmt::Display;
+   |                      ^^^^^^^^^^^^^^^^^ required by this bound in `Foo::{opaque#0}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs b/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
index bb4e0d44f..fcd0b51ee 100644
--- a/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
+++ b/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.current.stderr b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.current.stderr
new file mode 100644
index 000000000..b8a793e1a
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.current.stderr
@@ -0,0 +1,21 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/dont-project-to-rpitit-with-no-value.rs:4:12
+   |
+LL | #![feature(return_position_impl_trait_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[E0046]: not all trait items implemented, missing: `foo`
+  --> $DIR/dont-project-to-rpitit-with-no-value.rs:12:1
+   |
+LL |     fn foo(&self) -> impl Sized;
+   |     ---------------------------- `foo` from trait
+...
+LL | impl MyTrait for i32 {
+   | ^^^^^^^^^^^^^^^^^^^^ missing `foo` in implementation
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0046`.
diff --git a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.next.stderr b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.next.stderr
new file mode 100644
index 000000000..b8a793e1a
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.next.stderr
@@ -0,0 +1,21 @@
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/dont-project-to-rpitit-with-no-value.rs:4:12
+   |
+LL | #![feature(return_position_impl_trait_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[E0046]: not all trait items implemented, missing: `foo`
+  --> $DIR/dont-project-to-rpitit-with-no-value.rs:12:1
+   |
+LL |     fn foo(&self) -> impl Sized;
+   |     ---------------------------- `foo` from trait
+...
+LL | impl MyTrait for i32 {
+   | ^^^^^^^^^^^^^^^^^^^^ missing `foo` in implementation
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0046`.
diff --git a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs
new file mode 100644
index 000000000..8329ce1f8
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs
@@ -0,0 +1,19 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
+#![feature(return_position_impl_trait_in_trait)]
+//~^ WARN the feature `return_position_impl_trait_in_trait` is incomplete
+
+trait MyTrait {
+    fn foo(&self) -> impl Sized;
+    fn bar(&self) -> impl Sized;
+}
+
+impl MyTrait for i32 {
+    //~^ ERROR not all trait items implemented, missing: `foo`
+    fn bar(&self) -> impl Sized {
+        self.foo()
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/early.rs b/tests/ui/impl-trait/in-trait/early.rs
index 9c1c2b503..831033a58 100644
--- a/tests/ui/impl-trait/in-trait/early.rs
+++ b/tests/ui/impl-trait/in-trait/early.rs
@@ -1,5 +1,7 @@
 // check-pass
 // edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/encode.rs b/tests/ui/impl-trait/in-trait/encode.rs
index efb9f6498..98aaf4a65 100644
--- a/tests/ui/impl-trait/in-trait/encode.rs
+++ b/tests/ui/impl-trait/in-trait/encode.rs
@@ -1,5 +1,7 @@
 // build-pass
 // compile-flags: --crate-type=lib
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/foreign.rs b/tests/ui/impl-trait/in-trait/foreign.rs
index 6341f5b42..f4972d948 100644
--- a/tests/ui/impl-trait/in-trait/foreign.rs
+++ b/tests/ui/impl-trait/in-trait/foreign.rs
@@ -1,9 +1,21 @@
 // check-pass
 // aux-build: rpitit.rs
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 extern crate rpitit;
 
+use std::sync::Arc;
+
+// Implement an RPITIT from another crate.
+struct Local;
+impl rpitit::Foo for Local {
+    fn bar() -> Arc<String> { Arc::new(String::new()) }
+}
+
 fn main() {
-    // Witness an RPITIT from another crate
-    let () = <rpitit::Foreign as rpitit::Foo>::bar();
+    // Witness an RPITIT from another crate.
+    let &() = <rpitit::Foreign as rpitit::Foo>::bar();
+
+    let x: Arc<String> = <Local as rpitit::Foo>::bar();
 }
diff --git a/tests/ui/impl-trait/in-trait/generics-mismatch.stderr b/tests/ui/impl-trait/in-trait/generics-mismatch.current.stderr
index cd42683e0..310edbcb6 100644
--- a/tests/ui/impl-trait/in-trait/generics-mismatch.stderr
+++ b/tests/ui/impl-trait/in-trait/generics-mismatch.current.stderr
@@ -1,5 +1,5 @@
 error[E0049]: method `bar` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/generics-mismatch.rs:11:12
+  --> $DIR/generics-mismatch.rs:14:12
    |
 LL |     fn bar(&self) -> impl Sized;
    |           - expected 0 type parameters
diff --git a/tests/ui/impl-trait/in-trait/generics-mismatch.next.stderr b/tests/ui/impl-trait/in-trait/generics-mismatch.next.stderr
new file mode 100644
index 000000000..310edbcb6
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/generics-mismatch.next.stderr
@@ -0,0 +1,12 @@
+error[E0049]: method `bar` has 1 type parameter but its trait declaration has 0 type parameters
+  --> $DIR/generics-mismatch.rs:14:12
+   |
+LL |     fn bar(&self) -> impl Sized;
+   |           - expected 0 type parameters
+...
+LL |     fn bar<T>(&self) {}
+   |            ^ found 1 type parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0049`.
diff --git a/tests/ui/impl-trait/in-trait/generics-mismatch.rs b/tests/ui/impl-trait/in-trait/generics-mismatch.rs
index cc0fc720e..9259ca193 100644
--- a/tests/ui/impl-trait/in-trait/generics-mismatch.rs
+++ b/tests/ui/impl-trait/in-trait/generics-mismatch.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/issue-102140.stderr b/tests/ui/impl-trait/in-trait/issue-102140.current.stderr
index 18bb63745..7aa7880e2 100644
--- a/tests/ui/impl-trait/in-trait/issue-102140.stderr
+++ b/tests/ui/impl-trait/in-trait/issue-102140.current.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:22
+  --> $DIR/issue-102140.rs:26:22
    |
 LL |         MyTrait::foo(&self)
    |         ------------ ^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
@@ -13,7 +13,7 @@ LL +         MyTrait::foo(self)
    |
 
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:9
+  --> $DIR/issue-102140.rs:26:9
    |
 LL |         MyTrait::foo(&self)
    |         ^^^^^^^^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
@@ -21,7 +21,7 @@ LL |         MyTrait::foo(&self)
    = help: the trait `MyTrait` is implemented for `Outer`
 
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:9
+  --> $DIR/issue-102140.rs:26:9
    |
 LL |         MyTrait::foo(&self)
    |         ^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
diff --git a/tests/ui/impl-trait/in-trait/issue-102140.next.stderr b/tests/ui/impl-trait/in-trait/issue-102140.next.stderr
new file mode 100644
index 000000000..7aa7880e2
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/issue-102140.next.stderr
@@ -0,0 +1,33 @@
+error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+  --> $DIR/issue-102140.rs:26:22
+   |
+LL |         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
+   |
+LL -         MyTrait::foo(&self)
+LL +         MyTrait::foo(self)
+   |
+
+error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+  --> $DIR/issue-102140.rs:26:9
+   |
+LL |         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
+  --> $DIR/issue-102140.rs:26:9
+   |
+LL |         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`.
diff --git a/tests/ui/impl-trait/in-trait/issue-102140.rs b/tests/ui/impl-trait/in-trait/issue-102140.rs
index be1e012ac..4dcac4f5b 100644
--- a/tests/ui/impl-trait/in-trait/issue-102140.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102140.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/issue-102301.rs b/tests/ui/impl-trait/in-trait/issue-102301.rs
index a93714a65..1329ca29d 100644
--- a/tests/ui/impl-trait/in-trait/issue-102301.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102301.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/issue-102571.stderr b/tests/ui/impl-trait/in-trait/issue-102571.current.stderr
index 87219941d..cac9a29f6 100644
--- a/tests/ui/impl-trait/in-trait/issue-102571.stderr
+++ b/tests/ui/impl-trait/in-trait/issue-102571.current.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-102571.rs:20:9
+  --> $DIR/issue-102571.rs:23:9
    |
 LL |     let () = t.bar();
    |         ^^   ------- this expression has type `impl Deref<Target = impl std::fmt::Display + ?Sized>`
diff --git a/tests/ui/impl-trait/in-trait/issue-102571.next.stderr b/tests/ui/impl-trait/in-trait/issue-102571.next.stderr
new file mode 100644
index 000000000..cac9a29f6
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/issue-102571.next.stderr
@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-102571.rs:23:9
+   |
+LL |     let () = t.bar();
+   |         ^^   ------- this expression has type `impl Deref<Target = impl std::fmt::Display + ?Sized>`
+   |         |
+   |         expected associated type, found `()`
+   |
+   = note: expected associated type `impl Deref<Target = impl std::fmt::Display + ?Sized>`
+                    found unit type `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/impl-trait/in-trait/issue-102571.rs b/tests/ui/impl-trait/in-trait/issue-102571.rs
index 61c91e644..f0ddab5e7 100644
--- a/tests/ui/impl-trait/in-trait/issue-102571.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102571.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/nested-rpitit.rs b/tests/ui/impl-trait/in-trait/nested-rpitit.rs
index 65285e3a3..360207537 100644
--- a/tests/ui/impl-trait/in-trait/nested-rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/nested-rpitit.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/new-lowering-strategy/simple-trait.rs b/tests/ui/impl-trait/in-trait/new-lowering-strategy/simple-trait.rs
deleted file mode 100644
index dfce973d7..000000000
--- a/tests/ui/impl-trait/in-trait/new-lowering-strategy/simple-trait.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-// check-pass
-// compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
-
-#![feature(return_position_impl_trait_in_trait)]
-#![allow(incomplete_features)]
-
-trait Foo {
-    fn foo() -> impl Sized;
-}
-
-fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/object-safety.stderr b/tests/ui/impl-trait/in-trait/object-safety.current.stderr
index ca0e760ff..b7f2b019a 100644
--- a/tests/ui/impl-trait/in-trait/object-safety.stderr
+++ b/tests/ui/impl-trait/in-trait/object-safety.current.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:17:33
+  --> $DIR/object-safety.rs:20:33
    |
 LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
    |                                 ^^^^^^^^^^^^ `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>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:10:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -14,13 +14,13 @@ LL |     fn baz(&self) -> impl Debug;
    = help: consider moving `baz` to another trait
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:20:13
+  --> $DIR/object-safety.rs:23:13
    |
 LL |     let s = i.baz();
    |             ^^^^^^^ `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>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:10:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -29,13 +29,13 @@ LL |     fn baz(&self) -> impl Debug;
    = help: consider moving `baz` to another trait
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:17:13
+  --> $DIR/object-safety.rs:20:13
    |
 LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
    |             ^^^^^^^^^^^^^^^^ `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>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:10:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
diff --git a/tests/ui/impl-trait/in-trait/object-safety.next.stderr b/tests/ui/impl-trait/in-trait/object-safety.next.stderr
new file mode 100644
index 000000000..b7f2b019a
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/object-safety.next.stderr
@@ -0,0 +1,50 @@
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:20:33
+   |
+LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
+   |                                 ^^^^^^^^^^^^ `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>
+  --> $DIR/object-safety.rs:10:22
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |                      ^^^^^^^^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:23:13
+   |
+LL |     let s = i.baz();
+   |             ^^^^^^^ `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>
+  --> $DIR/object-safety.rs:10:22
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |                      ^^^^^^^^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:20:13
+   |
+LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
+   |             ^^^^^^^^^^^^^^^^ `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>
+  --> $DIR/object-safety.rs:10:22
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |                      ^^^^^^^^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+   = note: required for `Box<u32>` to implement `CoerceUnsized<Box<dyn Foo>>`
+   = note: required by cast to type `Box<dyn Foo>`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0038`.
diff --git a/tests/ui/impl-trait/in-trait/object-safety.rs b/tests/ui/impl-trait/in-trait/object-safety.rs
index dd35b9a2d..016a0aaae 100644
--- a/tests/ui/impl-trait/in-trait/object-safety.rs
+++ b/tests/ui/impl-trait/in-trait/object-safety.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.current.stderr
index 15edda483..a57653b2c 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.current.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/opaque-in-impl-is-opaque.rs:17:19
+  --> $DIR/opaque-in-impl-is-opaque.rs:20:19
    |
 LL |     fn bar(&self) -> impl Display {
    |                      ------------ the found opaque type
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.next.stderr b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.next.stderr
new file mode 100644
index 000000000..a57653b2c
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.next.stderr
@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/opaque-in-impl-is-opaque.rs:20:19
+   |
+LL |     fn bar(&self) -> impl Display {
+   |                      ------------ the found opaque type
+...
+LL |     let x: &str = ().bar();
+   |            ----   ^^^^^^^^ expected `&str`, found opaque type
+   |            |
+   |            expected due to this
+   |
+   = note: expected reference `&str`
+            found opaque type `impl std::fmt::Display`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
index 3ac264e8e..c07ece15a 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl.rs b/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
index 2e0662969..f48d9fa26 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/reveal.rs b/tests/ui/impl-trait/in-trait/reveal.rs
index d6ede1cc4..1f42ec744 100644
--- a/tests/ui/impl-trait/in-trait/reveal.rs
+++ b/tests/ui/impl-trait/in-trait/reveal.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.stderr b/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr
index c4fcaabe4..eba270af7 100644
--- a/tests/ui/impl-trait/in-trait/signature-mismatch.stderr
+++ b/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr
@@ -1,5 +1,5 @@
 error: `impl` item signature doesn't match `trait` item signature
-  --> $DIR/signature-mismatch.rs:15:5
+  --> $DIR/signature-mismatch.rs:17:5
    |
 LL |     fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
    |     ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3`
diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr b/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr
new file mode 100644
index 000000000..eba270af7
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr
@@ -0,0 +1,16 @@
+error: `impl` item signature doesn't match `trait` item signature
+  --> $DIR/signature-mismatch.rs:17:5
+   |
+LL |     fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
+   |     ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3`
+...
+LL |     fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2`
+   |
+   = note: expected signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3`
+              found signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2`
+   = help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait`
+   = help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output
+
+error: aborting due to previous error
+
diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.rs b/tests/ui/impl-trait/in-trait/signature-mismatch.rs
index 90682631a..38c902a97 100644
--- a/tests/ui/impl-trait/in-trait/signature-mismatch.rs
+++ b/tests/ui/impl-trait/in-trait/signature-mismatch.rs
@@ -1,4 +1,6 @@
 // edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/specialization-broken.stderr b/tests/ui/impl-trait/in-trait/specialization-broken.current.stderr
index dc621d6b8..f48e7a1ed 100644
--- a/tests/ui/impl-trait/in-trait/specialization-broken.stderr
+++ b/tests/ui/impl-trait/in-trait/specialization-broken.current.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `bar` has an incompatible type for trait
-  --> $DIR/specialization-broken.rs:16:22
+  --> $DIR/specialization-broken.rs:19:22
    |
 LL | default impl<U> Foo for U
    |              - this type parameter
@@ -11,7 +11,7 @@ LL |     fn bar(&self) -> U {
    |                      help: change the output type to match the trait: `impl Sized`
    |
 note: type in trait
-  --> $DIR/specialization-broken.rs:9:22
+  --> $DIR/specialization-broken.rs:12:22
    |
 LL |     fn bar(&self) -> impl Sized;
    |                      ^^^^^^^^^^
@@ -19,7 +19,7 @@ LL |     fn bar(&self) -> impl Sized;
               found signature `fn(&U) -> U`
 
 error: method with return-position `impl Trait` in trait cannot be specialized
-  --> $DIR/specialization-broken.rs:16:5
+  --> $DIR/specialization-broken.rs:19:5
    |
 LL |     fn bar(&self) -> U {
    |     ^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/impl-trait/in-trait/specialization-broken.next.stderr b/tests/ui/impl-trait/in-trait/specialization-broken.next.stderr
new file mode 100644
index 000000000..f48e7a1ed
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/specialization-broken.next.stderr
@@ -0,0 +1,31 @@
+error[E0053]: method `bar` has an incompatible type for trait
+  --> $DIR/specialization-broken.rs:19:22
+   |
+LL | default impl<U> Foo for U
+   |              - this type parameter
+...
+LL |     fn bar(&self) -> U {
+   |                      ^
+   |                      |
+   |                      expected associated type, found type parameter `U`
+   |                      help: change the output type to match the trait: `impl Sized`
+   |
+note: type in trait
+  --> $DIR/specialization-broken.rs:12:22
+   |
+LL |     fn bar(&self) -> impl Sized;
+   |                      ^^^^^^^^^^
+   = note: expected signature `fn(&U) -> impl Sized`
+              found signature `fn(&U) -> U`
+
+error: method with return-position `impl Trait` in trait cannot be specialized
+  --> $DIR/specialization-broken.rs:19:5
+   |
+LL |     fn bar(&self) -> U {
+   |     ^^^^^^^^^^^^^^^^^^
+   |
+   = note: specialization behaves in inconsistent and surprising ways with `#![feature(return_position_impl_trait_in_trait)]`, and for now is disallowed
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0053`.
diff --git a/tests/ui/impl-trait/in-trait/specialization-broken.rs b/tests/ui/impl-trait/in-trait/specialization-broken.rs
index 2fcffdf3f..658d07097 100644
--- a/tests/ui/impl-trait/in-trait/specialization-broken.rs
+++ b/tests/ui/impl-trait/in-trait/specialization-broken.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 // FIXME(compiler-errors): I'm not exactly sure if this is expected to pass or not.
 // But we fixed an ICE anyways.
 
diff --git a/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs b/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
index c9ee877db..dbc5d38f1 100644
--- a/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
+++ b/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(specialization)]
 #![feature(return_position_impl_trait_in_trait)]
diff --git a/tests/ui/impl-trait/in-trait/success.rs b/tests/ui/impl-trait/in-trait/success.rs
index 4cbe682b4..0e69e0490 100644
--- a/tests/ui/impl-trait/in-trait/success.rs
+++ b/tests/ui/impl-trait/in-trait/success.rs
@@ -1,4 +1,6 @@
 // check-pass
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.current.stderr
index 8ff54cad9..64c942705 100644
--- a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr
+++ b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.current.stderr
@@ -1,5 +1,5 @@
 error[E0049]: method `bar` has 0 type parameters but its trait declaration has 1 type parameter
-  --> $DIR/trait-more-generics-than-impl.rs:11:11
+  --> $DIR/trait-more-generics-than-impl.rs:14:11
    |
 LL |     fn bar<T>() -> impl Sized;
    |            - expected 1 type parameter
diff --git a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.next.stderr b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.next.stderr
new file mode 100644
index 000000000..64c942705
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.next.stderr
@@ -0,0 +1,12 @@
+error[E0049]: method `bar` has 0 type parameters but its trait declaration has 1 type parameter
+  --> $DIR/trait-more-generics-than-impl.rs:14:11
+   |
+LL |     fn bar<T>() -> impl Sized;
+   |            - expected 1 type parameter
+...
+LL |     fn bar() -> impl Sized {}
+   |           ^ found 0 type parameters
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0049`.
diff --git a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
index 0bbe50ea6..c2e394a1f 100644
--- a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
+++ b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
@@ -1,3 +1,6 @@
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.stderr b/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr
index 03cc4c2b9..1a7071612 100644
--- a/tests/ui/impl-trait/in-trait/wf-bounds.stderr
+++ b/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/wf-bounds.rs:9:22
+  --> $DIR/wf-bounds.rs:13:22
    |
 LL |     fn nya() -> impl Wf<Vec<[u8]>>;
    |                      ^^^^^^^^^^^^^ doesn't have a size known at compile-time
@@ -9,22 +9,32 @@ note: required by a bound in `Vec`
   --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
 
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/wf-bounds.rs:12:23
+  --> $DIR/wf-bounds.rs:16:23
    |
 LL |     fn nya2() -> impl Wf<[u8]>;
    |                       ^^^^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `[u8]`
 note: required by a bound in `Wf`
-  --> $DIR/wf-bounds.rs:6:10
+  --> $DIR/wf-bounds.rs:8:10
    |
-LL | trait Wf<T> {}
+LL | trait Wf<T> {
    |          ^ required by this bound in `Wf`
 help: consider relaxing the implicit `Sized` restriction
    |
-LL | trait Wf<T: ?Sized> {}
+LL | trait Wf<T: ?Sized> {
    |           ++++++++
 
-error: aborting due to 2 previous errors
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:19:44
+   |
+LL |     fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>;
+   |                                            ^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Vec`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr b/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr
new file mode 100644
index 000000000..1a7071612
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr
@@ -0,0 +1,40 @@
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:13:22
+   |
+LL |     fn nya() -> impl Wf<Vec<[u8]>>;
+   |                      ^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Vec`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:16:23
+   |
+LL |     fn nya2() -> impl Wf<[u8]>;
+   |                       ^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Wf`
+  --> $DIR/wf-bounds.rs:8:10
+   |
+LL | trait Wf<T> {
+   |          ^ required by this bound in `Wf`
+help: consider relaxing the implicit `Sized` restriction
+   |
+LL | trait Wf<T: ?Sized> {
+   |           ++++++++
+
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:19:44
+   |
+LL |     fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>;
+   |                                            ^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Vec`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.rs b/tests/ui/impl-trait/in-trait/wf-bounds.rs
index 2c71583b3..1c9590bd8 100644
--- a/tests/ui/impl-trait/in-trait/wf-bounds.rs
+++ b/tests/ui/impl-trait/in-trait/wf-bounds.rs
@@ -1,9 +1,13 @@
 // issue #101663
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
-trait Wf<T> {}
+trait Wf<T> {
+    type Output;
+}
 
 trait Uwu {
     fn nya() -> impl Wf<Vec<[u8]>>;
@@ -11,6 +15,9 @@ trait Uwu {
 
     fn nya2() -> impl Wf<[u8]>;
     //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time
+
+    fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>;
+    //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time
 }
 
 fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/where-clause.rs b/tests/ui/impl-trait/in-trait/where-clause.rs
index 87bac519c..88d86e2b5 100644
--- a/tests/ui/impl-trait/in-trait/where-clause.rs
+++ b/tests/ui/impl-trait/in-trait/where-clause.rs
@@ -1,5 +1,7 @@
 // check-pass
 // edition: 2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
 
 #![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/impl-trait/issue-55872-1.rs b/tests/ui/impl-trait/issue-55872-1.rs
index 22ff7ffa2..f36a310dd 100644
--- a/tests/ui/impl-trait/issue-55872-1.rs
+++ b/tests/ui/impl-trait/issue-55872-1.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 pub trait Bar {
     type E: Copy;
diff --git a/tests/ui/impl-trait/issue-55872-2.rs b/tests/ui/impl-trait/issue-55872-2.rs
index cbc7b5d62..7a5cb3b3d 100644
--- a/tests/ui/impl-trait/issue-55872-2.rs
+++ b/tests/ui/impl-trait/issue-55872-2.rs
@@ -3,7 +3,7 @@
 // [drop_tracking_mir] compile-flags: -Zdrop-tracking-mir
 // edition:2018
 
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 pub trait Bar {
     type E: Send;
diff --git a/tests/ui/impl-trait/issue-55872-2.stderr b/tests/ui/impl-trait/issue-55872-2.stderr
deleted file mode 100644
index 477c964bd..000000000
--- a/tests/ui/impl-trait/issue-55872-2.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
-  --> $DIR/issue-55872-2.rs:17:9
-   |
-LL |         async {}
-   |         ^^^^^^^^
-
-error: aborting due to previous error
-
diff --git a/tests/ui/impl-trait/issue-55872-3.rs b/tests/ui/impl-trait/issue-55872-3.rs
index 91811df93..d031271ac 100644
--- a/tests/ui/impl-trait/issue-55872-3.rs
+++ b/tests/ui/impl-trait/issue-55872-3.rs
@@ -1,7 +1,7 @@
 // edition:2018
 // ignore-compare-mode-chalk
 
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 pub trait Bar {
     type E: Copy;
diff --git a/tests/ui/impl-trait/issue-55872.rs b/tests/ui/impl-trait/issue-55872.rs
index c4e6f6436..10850f0a9 100644
--- a/tests/ui/impl-trait/issue-55872.rs
+++ b/tests/ui/impl-trait/issue-55872.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 pub trait Bar {
     type E: Copy;
diff --git a/tests/ui/impl-trait/issues/issue-78722.rs b/tests/ui/impl-trait/issues/issue-78722.rs
index 78233f300..7b5ab5f22 100644
--- a/tests/ui/impl-trait/issues/issue-78722.rs
+++ b/tests/ui/impl-trait/issues/issue-78722.rs
@@ -12,7 +12,6 @@ struct Bug {
         }
         let f: F = async { 1 };
         //~^ ERROR `async` blocks are not allowed in constants
-        //~| ERROR destructor of
         1
     }],
 }
diff --git a/tests/ui/impl-trait/issues/issue-78722.stderr b/tests/ui/impl-trait/issues/issue-78722.stderr
index c00df8087..05a2c135c 100644
--- a/tests/ui/impl-trait/issues/issue-78722.stderr
+++ b/tests/ui/impl-trait/issues/issue-78722.stderr
@@ -7,22 +7,13 @@ LL |         let f: F = async { 1 };
    = note: see issue #85368 <https://github.com/rust-lang/rust/issues/85368> for more information
    = help: add `#![feature(const_async_blocks)]` to the crate attributes to enable
 
-error[E0493]: destructor of `F` cannot be evaluated at compile-time
-  --> $DIR/issue-78722.rs:13:13
-   |
-LL |         let f: F = async { 1 };
-   |             ^ the destructor for this type cannot be evaluated in constants
-...
-LL |     }],
-   |     - value is dropped here
-
 error[E0271]: expected `[async block@$DIR/issue-78722.rs:11:13: 11:21]` to be a future that resolves to `u8`, but it resolves to `()`
   --> $DIR/issue-78722.rs:9:30
    |
 LL |         fn concrete_use() -> F {
    |                              ^ expected `()`, found `u8`
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0271, E0493, E0658.
+Some errors have detailed explanations: E0271, E0658.
 For more information about an error, try `rustc --explain E0271`.
diff --git a/tests/ui/impl-trait/issues/issue-82139.rs b/tests/ui/impl-trait/issues/issue-82139.rs
index cc9167b34..3f0b0f1a8 100644
--- a/tests/ui/impl-trait/issues/issue-82139.rs
+++ b/tests/ui/impl-trait/issues/issue-82139.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 trait Trait {
     type Associated;
diff --git a/tests/ui/impl-trait/issues/issue-83919.rs b/tests/ui/impl-trait/issues/issue-83919.rs
index e76443a65..4e699e7f3 100644
--- a/tests/ui/impl-trait/issues/issue-83919.rs
+++ b/tests/ui/impl-trait/issues/issue-83919.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 // edition:2021
 
@@ -6,8 +6,8 @@ use std::future::Future;
 
 trait Foo {
     type T;
-    type Fut2: Future<Output=Self::T>; // ICE got triggered with traits other than Future here
-    type Fut: Future<Output=Self::Fut2>;
+    type Fut2: Future<Output = Self::T>; // ICE got triggered with traits other than Future here
+    type Fut: Future<Output = Self::Fut2>;
     fn get_fut(&self) -> Self::Fut;
 }
 
@@ -15,11 +15,11 @@ struct Implementor;
 
 impl Foo for Implementor {
     type T = u64;
-    type Fut2 = impl Future<Output=u64>;
-    type Fut = impl Future<Output=Self::Fut2>;
+    type Fut2 = impl Future<Output = u64>;
+    type Fut = impl Future<Output = Self::Fut2>;
 
     fn get_fut(&self) -> Self::Fut {
-    //~^ ERROR `{integer}` is not a future
+        //~^ ERROR `{integer}` is not a future
         async move {
             42
             // 42 does not impl Future and rustc does actually point out the error,
diff --git a/tests/ui/impl-trait/issues/issue-86719.rs b/tests/ui/impl-trait/issues/issue-86719.rs
index f4b0b3f33..7abab5bfb 100644
--- a/tests/ui/impl-trait/issues/issue-86719.rs
+++ b/tests/ui/impl-trait/issues/issue-86719.rs
@@ -1,11 +1,12 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 trait Bar {
     type E;
 }
 impl<S> Bar for S {
     type E = impl ; //~ ERROR at least one trait must be specified
-    fn foo() -> Self::E { //~ ERROR `foo` is not a member
+    fn foo() -> Self::E {
+        //~^ ERROR `foo` is not a member
         |_| true //~ ERROR type annotations needed
     }
 }
diff --git a/tests/ui/impl-trait/issues/issue-86719.stderr b/tests/ui/impl-trait/issues/issue-86719.stderr
index 7592418fd..15893df5f 100644
--- a/tests/ui/impl-trait/issues/issue-86719.stderr
+++ b/tests/ui/impl-trait/issues/issue-86719.stderr
@@ -8,12 +8,13 @@ error[E0407]: method `foo` is not a member of trait `Bar`
   --> $DIR/issue-86719.rs:8:5
    |
 LL | /     fn foo() -> Self::E {
+LL | |
 LL | |         |_| true
 LL | |     }
    | |_____^ not a member of trait `Bar`
 
 error[E0282]: type annotations needed
-  --> $DIR/issue-86719.rs:9:10
+  --> $DIR/issue-86719.rs:10:10
    |
 LL |         |_| true
    |          ^
diff --git a/tests/ui/impl-trait/issues/issue-87340.rs b/tests/ui/impl-trait/issues/issue-87340.rs
index f0f6d2bb6..705a4addc 100644
--- a/tests/ui/impl-trait/issues/issue-87340.rs
+++ b/tests/ui/impl-trait/issues/issue-87340.rs
@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 trait X {
     type I;
@@ -6,7 +6,7 @@ trait X {
 }
 
 impl<T> X for () {
-//~^ ERROR `T` is not constrained by the impl trait, self type, or predicates
+    //~^ ERROR `T` is not constrained by the impl trait, self type, or predicates
     type I = impl Sized;
     fn f() -> Self::I {}
 }
diff --git a/tests/ui/impl-trait/multiple-lifetimes.rs b/tests/ui/impl-trait/multiple-lifetimes/multiple-lifetimes.rs
index 5407fb6dd..5407fb6dd 100644
--- a/tests/ui/impl-trait/multiple-lifetimes.rs
+++ b/tests/ui/impl-trait/multiple-lifetimes/multiple-lifetimes.rs
diff --git a/tests/ui/impl-trait/nested-return-type2.rs b/tests/ui/impl-trait/nested-return-type2.rs
index fe883ce6f..e1d551137 100644
--- a/tests/ui/impl-trait/nested-return-type2.rs
+++ b/tests/ui/impl-trait/nested-return-type2.rs
@@ -26,7 +26,6 @@ impl<R: Duh, F: FnMut() -> R> Trait for F {
 // Lazy TAIT would error out, but we inserted a hack to make it work again,
 // keeping backwards compatibility.
 fn foo() -> impl Trait<Assoc = impl Send> {
-    //~^ WARN opaque type `impl Trait<Assoc = impl Send>` does not satisfy its associated type bounds
     || 42
 }
 
diff --git a/tests/ui/impl-trait/nested-return-type2.stderr b/tests/ui/impl-trait/nested-return-type2.stderr
deleted file mode 100644
index 09ad3bd05..000000000
--- a/tests/ui/impl-trait/nested-return-type2.stderr
+++ /dev/null
@@ -1,17 +0,0 @@
-warning: opaque type `impl Trait<Assoc = impl Send>` does not satisfy its associated type bounds
-  --> $DIR/nested-return-type2.rs:28:24
-   |
-LL |     type Assoc: Duh;
-   |                 --- this associated type bound is unsatisfied for `impl Send`
-...
-LL | fn foo() -> impl Trait<Assoc = impl Send> {
-   |                        ^^^^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(opaque_hidden_inferred_bound)]` on by default
-help: add this bound
-   |
-LL | fn foo() -> impl Trait<Assoc = impl Send + Duh> {
-   |                                          +++++
-
-warning: 1 warning emitted
-
diff --git a/tests/ui/impl-trait/nested-return-type3.rs b/tests/ui/impl-trait/nested-return-type3.rs
index 5a764fc4c..74b4dae22 100644
--- a/tests/ui/impl-trait/nested-return-type3.rs
+++ b/tests/ui/impl-trait/nested-return-type3.rs
@@ -13,7 +13,6 @@ impl<F: Duh> Trait for F {
 }
 
 fn foo() -> impl Trait<Assoc = impl Send> {
-    //~^ WARN opaque type `impl Trait<Assoc = impl Send>` does not satisfy its associated type bounds
     42
 }
 
diff --git a/tests/ui/impl-trait/nested-return-type3.stderr b/tests/ui/impl-trait/nested-return-type3.stderr
deleted file mode 100644
index 632de71aa..000000000
--- a/tests/ui/impl-trait/nested-return-type3.stderr
+++ /dev/null
@@ -1,17 +0,0 @@
-warning: opaque type `impl Trait<Assoc = impl Send>` does not satisfy its associated type bounds
-  --> $DIR/nested-return-type3.rs:15:24
-   |
-LL |     type Assoc: Duh;
-   |                 --- this associated type bound is unsatisfied for `impl Send`
-...
-LL | fn foo() -> impl Trait<Assoc = impl Send> {
-   |                        ^^^^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(opaque_hidden_inferred_bound)]` on by default
-help: add this bound
-   |
-LL | fn foo() -> impl Trait<Assoc = impl Send + Duh> {
-   |                                          +++++
-
-warning: 1 warning emitted
-
diff --git a/tests/ui/impl-trait/no-method-suggested-traits.stderr b/tests/ui/impl-trait/no-method-suggested-traits.stderr
index 3c2c01dc2..160cc0440 100644
--- a/tests/ui/impl-trait/no-method-suggested-traits.stderr
+++ b/tests/ui/impl-trait/no-method-suggested-traits.stderr
@@ -7,13 +7,13 @@ LL |     1u32.method();
    = help: items from traits can only be used if the trait is in scope
 help: the following traits are implemented but not in scope; perhaps add a `use` for one of them:
    |
-LL | use foo::Bar;
+LL + use foo::Bar;
    |
-LL | use no_method_suggested_traits::Reexported;
+LL + use no_method_suggested_traits::Reexported;
    |
-LL | use no_method_suggested_traits::foo::PubPub;
+LL + use no_method_suggested_traits::foo::PubPub;
    |
-LL | use no_method_suggested_traits::qux::PrivPub;
+LL + use no_method_suggested_traits::qux::PrivPub;
    |
 
 error[E0599]: no method named `method` found for struct `Rc<&mut Box<&u32>>` in the current scope
@@ -25,13 +25,13 @@ LL |     std::rc::Rc::new(&mut Box::new(&1u32)).method();
    = help: items from traits can only be used if the trait is in scope
 help: the following traits are implemented but not in scope; perhaps add a `use` for one of them:
    |
-LL | use foo::Bar;
+LL + use foo::Bar;
    |
-LL | use no_method_suggested_traits::Reexported;
+LL + use no_method_suggested_traits::Reexported;
    |
-LL | use no_method_suggested_traits::foo::PubPub;
+LL + use no_method_suggested_traits::foo::PubPub;
    |
-LL | use no_method_suggested_traits::qux::PrivPub;
+LL + use no_method_suggested_traits::qux::PrivPub;
    |
 
 error[E0599]: no method named `method` found for type `char` in the current scope
@@ -46,7 +46,7 @@ LL |     'a'.method();
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
-LL | use foo::Bar;
+LL + use foo::Bar;
    |
 
 error[E0599]: no method named `method` found for struct `Rc<&mut Box<&char>>` in the current scope
@@ -58,7 +58,7 @@ LL |     std::rc::Rc::new(&mut Box::new(&'a')).method();
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
-LL | use foo::Bar;
+LL + use foo::Bar;
    |
 
 error[E0599]: no method named `method` found for type `i32` in the current scope
@@ -75,7 +75,7 @@ LL |         fn method(&self) {}
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
-LL | use no_method_suggested_traits::foo::PubPub;
+LL + use no_method_suggested_traits::foo::PubPub;
    |
 
 error[E0599]: no method named `method` found for struct `Rc<&mut Box<&i32>>` in the current scope
@@ -87,7 +87,7 @@ LL |     std::rc::Rc::new(&mut Box::new(&1i32)).method();
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
-LL | use no_method_suggested_traits::foo::PubPub;
+LL + use no_method_suggested_traits::foo::PubPub;
    |
 
 error[E0599]: no method named `method` found for struct `Foo` in the current scope
diff --git a/tests/ui/impl-trait/recursive-impl-trait-type-indirect.drop_tracking_mir.stderr b/tests/ui/impl-trait/recursive-impl-trait-type-indirect.drop_tracking_mir.stderr
index 662c74bcd..9c67f17e9 100644
--- a/tests/ui/impl-trait/recursive-impl-trait-type-indirect.drop_tracking_mir.stderr
+++ b/tests/ui/impl-trait/recursive-impl-trait-type-indirect.drop_tracking_mir.stderr
@@ -114,6 +114,9 @@ error[E0720]: cannot resolve opaque type
    |
 LL | fn generator_hold() -> impl Sized {
    |                        ^^^^^^^^^^ recursive opaque type
+...
+LL |         let x = generator_hold();
+   |             - generator captures itself here
 
 error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:90:26
diff --git a/tests/ui/impl-trait/type-alias-generic-param.rs b/tests/ui/impl-trait/type-alias-generic-param.rs
index 3499b2859..1211625da 100644
--- a/tests/ui/impl-trait/type-alias-generic-param.rs
+++ b/tests/ui/impl-trait/type-alias-generic-param.rs
@@ -3,7 +3,7 @@
 // types in 'item' position when generic parameters are involved
 //
 // run-pass
-#![feature(type_alias_impl_trait)]
+#![feature(impl_trait_in_assoc_type)]
 
 trait Meow {
     type MeowType;
diff --git a/tests/ui/impl-trait/universal_wrong_bounds.stderr b/tests/ui/impl-trait/universal_wrong_bounds.stderr
index 3b1a5e5f4..464d68958 100644
--- a/tests/ui/impl-trait/universal_wrong_bounds.stderr
+++ b/tests/ui/impl-trait/universal_wrong_bounds.stderr
@@ -6,7 +6,7 @@ LL | fn wants_debug(g: impl Debug) { }
    |
 help: consider importing this trait instead
    |
-LL | use std::fmt::Debug;
+LL + use std::fmt::Debug;
    |
 
 error[E0404]: expected trait, found derive macro `Debug`
@@ -17,7 +17,7 @@ LL | fn wants_display(g: impl Debug) { }
    |
 help: consider importing this trait instead
    |
-LL | use std::fmt::Debug;
+LL + use std::fmt::Debug;
    |
 
 error: aborting due to 2 previous errors
diff --git a/tests/ui/impl-trait/where-allowed.rs b/tests/ui/impl-trait/where-allowed.rs
index ff63b04c2..509d27166 100644
--- a/tests/ui/impl-trait/where-allowed.rs
+++ b/tests/ui/impl-trait/where-allowed.rs
@@ -1,6 +1,8 @@
 //! A simple test for testing many permutations of allowedness of
 //! impl Trait
 #![feature(impl_trait_in_fn_trait_return)]
+#![feature(custom_inner_attributes)]
+#![rustfmt::skip]
 use std::fmt::Debug;
 
 // Allowed
@@ -116,7 +118,7 @@ trait DummyTrait {
 }
 impl DummyTrait for () {
     type Out = impl Debug;
-    //~^ ERROR `impl Trait` in type aliases is unstable
+    //~^ ERROR `impl Trait` in associated types is unstable
 
     fn in_trait_impl_parameter(_: impl Debug) { }
     // Allowed
diff --git a/tests/ui/impl-trait/where-allowed.stderr b/tests/ui/impl-trait/where-allowed.stderr
index 1cae3f77c..3e2934379 100644
--- a/tests/ui/impl-trait/where-allowed.stderr
+++ b/tests/ui/impl-trait/where-allowed.stderr
@@ -1,5 +1,5 @@
 error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/where-allowed.rs:47:51
+  --> $DIR/where-allowed.rs:49:51
    |
 LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                           --------^^^^^^^^^^-
@@ -8,7 +8,7 @@ LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                           outer `impl Trait`
 
 error[E0666]: nested `impl Trait` is not allowed
-  --> $DIR/where-allowed.rs:56:57
+  --> $DIR/where-allowed.rs:58:57
    |
 LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
    |                                                 --------^^^^^^^^^^-
@@ -16,17 +16,17 @@ LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic
    |                                                 |       nested `impl Trait` here
    |                                                 outer `impl Trait`
 
-error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:118:16
+error[E0658]: `impl Trait` in associated types is unstable
+  --> $DIR/where-allowed.rs:120:16
    |
 LL |     type Out = impl Debug;
    |                ^^^^^^^^^^
    |
    = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
-   = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
+   = help: add `#![feature(impl_trait_in_assoc_type)]` to the crate attributes to enable
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:153:23
+  --> $DIR/where-allowed.rs:155:23
    |
 LL | type InTypeAlias<R> = impl Debug;
    |                       ^^^^^^^^^^
@@ -35,7 +35,7 @@ LL | type InTypeAlias<R> = impl Debug;
    = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:156:39
+  --> $DIR/where-allowed.rs:158:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
@@ -44,109 +44,109 @@ LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `fn` pointer params
-  --> $DIR/where-allowed.rs:16:40
+  --> $DIR/where-allowed.rs:18:40
    |
 LL | fn in_fn_parameter_in_parameters(_: fn(impl Debug)) { panic!() }
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `fn` pointer return types
-  --> $DIR/where-allowed.rs:20:42
+  --> $DIR/where-allowed.rs:22:42
    |
 LL | fn in_fn_return_in_parameters(_: fn() -> impl Debug) { panic!() }
    |                                          ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `fn` pointer params
-  --> $DIR/where-allowed.rs:24:38
+  --> $DIR/where-allowed.rs:26:38
    |
 LL | fn in_fn_parameter_in_return() -> fn(impl Debug) { panic!() }
    |                                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `fn` pointer return types
-  --> $DIR/where-allowed.rs:28:40
+  --> $DIR/where-allowed.rs:30:40
    |
 LL | fn in_fn_return_in_return() -> fn() -> impl Debug { panic!() }
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:32:49
+  --> $DIR/where-allowed.rs:34:49
    |
 LL | fn in_dyn_Fn_parameter_in_parameters(_: &dyn Fn(impl Debug)) { panic!() }
    |                                                 ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait return types
-  --> $DIR/where-allowed.rs:36:51
+  --> $DIR/where-allowed.rs:38:51
    |
 LL | fn in_dyn_Fn_return_in_parameters(_: &dyn Fn() -> impl Debug) { panic!() }
    |                                                   ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:40:55
+  --> $DIR/where-allowed.rs:42:55
    |
 LL | fn in_dyn_Fn_parameter_in_return() -> &'static dyn Fn(impl Debug) { panic!() }
    |                                                       ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:47:51
+  --> $DIR/where-allowed.rs:49:51
    |
 LL | fn in_impl_Fn_parameter_in_parameters(_: &impl Fn(impl Debug)) { panic!() }
    |                                                   ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait return types
-  --> $DIR/where-allowed.rs:52:53
+  --> $DIR/where-allowed.rs:54:53
    |
 LL | fn in_impl_Fn_return_in_parameters(_: &impl Fn() -> impl Debug) { panic!() }
    |                                                     ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:56:57
+  --> $DIR/where-allowed.rs:58:57
    |
 LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic!() }
    |                                                         ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:64:38
+  --> $DIR/where-allowed.rs:66:38
    |
 LL | fn in_Fn_parameter_in_generics<F: Fn(impl Debug)> (_: F) { panic!() }
    |                                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait return types
-  --> $DIR/where-allowed.rs:68:40
+  --> $DIR/where-allowed.rs:70:40
    |
 LL | fn in_Fn_return_in_generics<F: Fn() -> impl Debug> (_: F) { panic!() }
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in field types
-  --> $DIR/where-allowed.rs:81:32
+  --> $DIR/where-allowed.rs:83:32
    |
 LL | struct InBraceStructField { x: impl Debug }
    |                                ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in field types
-  --> $DIR/where-allowed.rs:85:41
+  --> $DIR/where-allowed.rs:87:41
    |
 LL | struct InAdtInBraceStructField { x: Vec<impl Debug> }
    |                                         ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in field types
-  --> $DIR/where-allowed.rs:89:27
+  --> $DIR/where-allowed.rs:91:27
    |
 LL | struct InTupleStructField(impl Debug);
    |                           ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in field types
-  --> $DIR/where-allowed.rs:94:25
+  --> $DIR/where-allowed.rs:96:25
    |
 LL |     InBraceVariant { x: impl Debug },
    |                         ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in field types
-  --> $DIR/where-allowed.rs:96:20
+  --> $DIR/where-allowed.rs:98:20
    |
 LL |     InTupleVariant(impl Debug),
    |                    ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in trait method return types
-  --> $DIR/where-allowed.rs:107:23
+  --> $DIR/where-allowed.rs:109:23
    |
 LL |     fn in_return() -> impl Debug;
    |                       ^^^^^^^^^^
@@ -155,7 +155,7 @@ LL |     fn in_return() -> impl Debug;
    = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `impl` method return types
-  --> $DIR/where-allowed.rs:124:34
+  --> $DIR/where-allowed.rs:126:34
    |
 LL |     fn in_trait_impl_return() -> impl Debug { () }
    |                                  ^^^^^^^^^^
@@ -164,127 +164,127 @@ LL |     fn in_trait_impl_return() -> impl Debug { () }
    = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `extern fn` params
-  --> $DIR/where-allowed.rs:137:33
+  --> $DIR/where-allowed.rs:139:33
    |
 LL |     fn in_foreign_parameters(_: impl Debug);
    |                                 ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `extern fn` return types
-  --> $DIR/where-allowed.rs:140:31
+  --> $DIR/where-allowed.rs:142:31
    |
 LL |     fn in_foreign_return() -> impl Debug;
    |                               ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `fn` pointer return types
-  --> $DIR/where-allowed.rs:156:39
+  --> $DIR/where-allowed.rs:158:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in traits
-  --> $DIR/where-allowed.rs:161:16
+  --> $DIR/where-allowed.rs:163:16
    |
 LL | impl PartialEq<impl Debug> for () {
    |                ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in impl headers
-  --> $DIR/where-allowed.rs:166:24
+  --> $DIR/where-allowed.rs:168:24
    |
 LL | impl PartialEq<()> for impl Debug {
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in impl headers
-  --> $DIR/where-allowed.rs:171:6
+  --> $DIR/where-allowed.rs:173:6
    |
 LL | impl impl Debug {
    |      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in impl headers
-  --> $DIR/where-allowed.rs:177:24
+  --> $DIR/where-allowed.rs:179:24
    |
 LL | impl InInherentImplAdt<impl Debug> {
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in bounds
-  --> $DIR/where-allowed.rs:183:11
+  --> $DIR/where-allowed.rs:185:11
    |
 LL |     where impl Debug: Debug
    |           ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in bounds
-  --> $DIR/where-allowed.rs:190:15
+  --> $DIR/where-allowed.rs:192:15
    |
 LL |     where Vec<impl Debug>: Debug
    |               ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in bounds
-  --> $DIR/where-allowed.rs:197:24
+  --> $DIR/where-allowed.rs:199:24
    |
 LL |     where T: PartialEq<impl Debug>
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:204:17
+  --> $DIR/where-allowed.rs:206:17
    |
 LL |     where T: Fn(impl Debug)
    |                 ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `Fn` trait return types
-  --> $DIR/where-allowed.rs:211:22
+  --> $DIR/where-allowed.rs:213:22
    |
 LL |     where T: Fn() -> impl Debug
    |                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:217:40
+  --> $DIR/where-allowed.rs:219:40
    |
 LL | struct InStructGenericParamDefault<T = impl Debug>(T);
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:221:36
+  --> $DIR/where-allowed.rs:223:36
    |
 LL | enum InEnumGenericParamDefault<T = impl Debug> { Variant(T) }
    |                                    ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:225:38
+  --> $DIR/where-allowed.rs:227:38
    |
 LL | trait InTraitGenericParamDefault<T = impl Debug> {}
    |                                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:229:41
+  --> $DIR/where-allowed.rs:231:41
    |
 LL | type InTypeAliasGenericParamDefault<T = impl Debug> = T;
    |                                         ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:233:11
+  --> $DIR/where-allowed.rs:235:11
    |
 LL | impl <T = impl Debug> T {}
    |           ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:240:40
+  --> $DIR/where-allowed.rs:242:40
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in variable bindings
-  --> $DIR/where-allowed.rs:246:29
+  --> $DIR/where-allowed.rs:248:29
    |
 LL |     let _in_local_variable: impl Fn() = || {};
    |                             ^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in closure return types
-  --> $DIR/where-allowed.rs:248:46
+  --> $DIR/where-allowed.rs:250:46
    |
 LL |     let _in_return_in_local_variable = || -> impl Fn() { || {} };
    |                                              ^^^^^^^^^
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:233:7
+  --> $DIR/where-allowed.rs:235:7
    |
 LL | impl <T = impl Debug> T {}
    |       ^^^^^^^^^^^^^^
@@ -294,7 +294,7 @@ LL | impl <T = impl Debug> T {}
    = note: `#[deny(invalid_type_param_default)]` on by default
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:240:36
+  --> $DIR/where-allowed.rs:242:36
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                    ^^^^^^^^^^^^^^
@@ -303,7 +303,7 @@ LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
 
 error[E0118]: no nominal type found for inherent implementation
-  --> $DIR/where-allowed.rs:233:1
+  --> $DIR/where-allowed.rs:235:1
    |
 LL | impl <T = impl Debug> T {}
    | ^^^^^^^^^^^^^^^^^^^^^^^ impl requires a nominal type