Merge from rustc

49 files changed, 1002 insertions, 334 deletions

diff --git a/tests/ui/associated-inherent-types/type-alias-bounds-are-enforced.rs b/tests/ui/associated-inherent-types/type-alias-bounds-are-enforced.rs
deleted file mode 100644
index 5ac7e1e58b8..00000000000
--- a/tests/ui/associated-inherent-types/type-alias-bounds-are-enforced.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-//@ compile-flags: --crate-type=lib
-//@ check-pass
-
-#![feature(inherent_associated_types)]
-#![allow(incomplete_features)]
-
-// Bounds on the self type play a major role in the resolution of inherent associated types (*).
-// As a result of that, if a type alias contains any then its bounds have to be respected and the
-// lint `type_alias_bounds` should not fire.
-
-#![deny(type_alias_bounds)]
-
-pub type Alias<T: Bound> = (Source<T>::Assoc,);
-
-pub struct Source<T>(T);
-pub trait Bound {}
-
-impl<T: Bound> Source<T> {
-    pub type Assoc = ();
-}
diff --git a/tests/ui/associated-inherent-types/type-alias-bounds.rs b/tests/ui/associated-inherent-types/type-alias-bounds.rs
new file mode 100644
index 00000000000..61641a83994
--- /dev/null
+++ b/tests/ui/associated-inherent-types/type-alias-bounds.rs
@@ -0,0 +1,29 @@
+//@ compile-flags: --crate-type=lib
+//@ check-pass
+
+#![feature(inherent_associated_types)]
+#![allow(incomplete_features)]
+
+// FIXME(inherent_associated_types):
+// While we currently do take some clauses of the ParamEnv into consideration
+// when performing IAT selection, we do not perform full well-formedness checking
+// for (eager) type alias definition and usage sites.
+//
+// Therefore it's *correct* for lint `type_alias_bounds` to fire here despite the
+// fact that removing `Bound` from `T` in `Alias` would lead to an error!
+//
+// Obviously, the present situation isn't ideal and we should fix it in one way
+// or another. Either we somehow delay IAT selection until after HIR ty lowering
+// to avoid the need to specify any bounds inside (eager) type aliases or we
+// force the overarching type alias to be *lazy* (similar to TAITs) which would
+// automatically lead to full wfchecking and lint TAB getting suppressed.
+
+pub type Alias<T: Bound> = (Source<T>::Assoc,);
+//~^ WARN bounds on generic parameters in type aliases are not enforced
+
+pub struct Source<T>(T);
+pub trait Bound {}
+
+impl<T: Bound> Source<T> {
+    pub type Assoc = ();
+}
diff --git a/tests/ui/associated-inherent-types/type-alias-bounds.stderr b/tests/ui/associated-inherent-types/type-alias-bounds.stderr
new file mode 100644
index 00000000000..c56dd498f77
--- /dev/null
+++ b/tests/ui/associated-inherent-types/type-alias-bounds.stderr
@@ -0,0 +1,16 @@
+warning: bounds on generic parameters in type aliases are not enforced
+  --> $DIR/type-alias-bounds.rs:21:19
+   |
+LL | pub type Alias<T: Bound> = (Source<T>::Assoc,);
+   |                 --^^^^^
+   |                 | |
+   |                 | will not be checked at usage sites of the type alias
+   |                 help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
+   = note: `#[warn(type_alias_bounds)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/associated-type-bounds/type-alias.stderr b/tests/ui/associated-type-bounds/type-alias.stderr
index 072c471467c..d59952b4a14 100644
--- a/tests/ui/associated-type-bounds/type-alias.stderr
+++ b/tests/ui/associated-type-bounds/type-alias.stderr
@@ -1,147 +1,159 @@
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:3:25
    |
 LL | type _TaWhere1<T> where T: Iterator<Item: Copy> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
    = note: `#[warn(type_alias_bounds)]` on by default
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere1<T> where T: Iterator<Item: Copy> = T;
-LL + type _TaWhere1<T>  = T;
-   |
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:4:25
    |
 LL | type _TaWhere2<T> where T: Iterator<Item: 'static> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere2<T> where T: Iterator<Item: 'static> = T;
-LL + type _TaWhere2<T>  = T;
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:5:25
    |
 LL | type _TaWhere3<T> where T: Iterator<Item: 'static> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere3<T> where T: Iterator<Item: 'static> = T;
-LL + type _TaWhere3<T>  = T;
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:6:25
    |
 LL | type _TaWhere4<T> where T: Iterator<Item: 'static + Copy + Send> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere4<T> where T: Iterator<Item: 'static + Copy + Send> = T;
-LL + type _TaWhere4<T>  = T;
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:7:25
    |
 LL | type _TaWhere5<T> where T: Iterator<Item: for<'a> Into<&'a u8>> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere5<T> where T: Iterator<Item: for<'a> Into<&'a u8>> = T;
-LL + type _TaWhere5<T>  = T;
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias.rs:8:25
    |
 LL | type _TaWhere6<T> where T: Iterator<Item: Iterator<Item: Copy>> = T;
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaWhere6<T> where T: Iterator<Item: Iterator<Item: Copy>> = T;
-LL + type _TaWhere6<T>  = T;
-   |
+   |                   ------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   |     |
+   |                   |     will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:10:20
    |
 LL | type _TaInline1<T: Iterator<Item: Copy>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline1<T: Iterator<Item: Copy>> = T;
-LL + type _TaInline1<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:11:20
    |
 LL | type _TaInline2<T: Iterator<Item: 'static>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline2<T: Iterator<Item: 'static>> = T;
-LL + type _TaInline2<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:12:20
    |
 LL | type _TaInline3<T: Iterator<Item: 'static>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline3<T: Iterator<Item: 'static>> = T;
-LL + type _TaInline3<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:13:20
    |
 LL | type _TaInline4<T: Iterator<Item: 'static + Copy + Send>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline4<T: Iterator<Item: 'static + Copy + Send>> = T;
-LL + type _TaInline4<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:14:20
    |
 LL | type _TaInline5<T: Iterator<Item: for<'a> Into<&'a u8>>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline5<T: Iterator<Item: for<'a> Into<&'a u8>>> = T;
-LL + type _TaInline5<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias.rs:15:20
    |
 LL | type _TaInline6<T: Iterator<Item: Iterator<Item: Copy>>> = T;
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type _TaInline6<T: Iterator<Item: Iterator<Item: Copy>>> = T;
-LL + type _TaInline6<T> = T;
-   |
+   |                  --^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  | |
+   |                  | will not be checked at usage sites of the type alias
+   |                  help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
 warning: 12 warnings emitted
 
diff --git a/tests/ui/async-await/async-closures/clone-closure.rs b/tests/ui/async-await/async-closures/clone-closure.rs
new file mode 100644
index 00000000000..807897e3e03
--- /dev/null
+++ b/tests/ui/async-await/async-closures/clone-closure.rs
@@ -0,0 +1,24 @@
+//@ aux-build:block-on.rs
+//@ edition:2021
+//@ run-pass
+//@ check-run-results
+
+#![feature(async_closure)]
+
+extern crate block_on;
+
+async fn for_each(f: impl async FnOnce(&str) + Clone) {
+    f.clone()("world").await;
+    f.clone()("world2").await;
+}
+
+fn main() {
+    block_on::block_on(async_main());
+}
+
+async fn async_main() {
+    let x = String::from("Hello,");
+    for_each(async move |s| {
+        println!("{x} {s}");
+    }).await;
+}
diff --git a/tests/ui/async-await/async-closures/clone-closure.run.stdout b/tests/ui/async-await/async-closures/clone-closure.run.stdout
new file mode 100644
index 00000000000..0cfcf1923da
--- /dev/null
+++ b/tests/ui/async-await/async-closures/clone-closure.run.stdout
@@ -0,0 +1,2 @@
+Hello, world
+Hello, world2
diff --git a/tests/ui/async-await/async-closures/move-consuming-capture.stderr b/tests/ui/async-await/async-closures/move-consuming-capture.stderr
index 45c1eac8f8f..4ce71ec49d6 100644
--- a/tests/ui/async-await/async-closures/move-consuming-capture.stderr
+++ b/tests/ui/async-await/async-closures/move-consuming-capture.stderr
@@ -11,6 +11,15 @@ LL |         x().await;
    |
 note: `async_call_once` takes ownership of the receiver `self`, which moves `x`
   --> $SRC_DIR/core/src/ops/async_function.rs:LL:COL
+help: you could `clone` the value and consume it, if the `NoCopy: Clone` trait bound could be satisfied
+   |
+LL |         x.clone()().await;
+   |          ++++++++
+help: consider annotating `NoCopy` with `#[derive(Clone)]`
+   |
+LL + #[derive(Clone)]
+LL | struct NoCopy;
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/async-await/async-closures/not-clone-closure.rs b/tests/ui/async-await/async-closures/not-clone-closure.rs
new file mode 100644
index 00000000000..2776ce4690f
--- /dev/null
+++ b/tests/ui/async-await/async-closures/not-clone-closure.rs
@@ -0,0 +1,36 @@
+//@ edition: 2021
+
+#![feature(async_closure)]
+
+struct NotClonableArg;
+#[derive(Default)]
+struct NotClonableReturnType;
+
+// Verify that the only components that we care about are the upvars, not the signature.
+fn we_are_okay_with_not_clonable_signature() {
+    let x = async |x: NotClonableArg| -> NotClonableReturnType { Default::default() };
+    x.clone(); // Okay
+}
+
+#[derive(Debug)]
+struct NotClonableUpvar;
+
+fn we_only_care_about_clonable_upvars() {
+    let x = NotClonableUpvar;
+    // Notably, this is clone because we capture `&x`.
+    let yes_clone = async || {
+        println!("{x:?}");
+    };
+    yes_clone.clone(); // Okay
+
+    let z = NotClonableUpvar;
+    // However, this is not because the closure captures `z` by move.
+    // (Even though the future that is lent out captures `z by ref!)
+    let not_clone = async move || {
+        println!("{z:?}");
+    };
+    not_clone.clone();
+    //~^ ERROR the trait bound `NotClonableUpvar: Clone` is not satisfied
+}
+
+fn main() {}
diff --git a/tests/ui/async-await/async-closures/not-clone-closure.stderr b/tests/ui/async-await/async-closures/not-clone-closure.stderr
new file mode 100644
index 00000000000..aea48a455c2
--- /dev/null
+++ b/tests/ui/async-await/async-closures/not-clone-closure.stderr
@@ -0,0 +1,20 @@
+error[E0277]: the trait bound `NotClonableUpvar: Clone` is not satisfied in `{async closure@$DIR/not-clone-closure.rs:29:21: 29:34}`
+  --> $DIR/not-clone-closure.rs:32:15
+   |
+LL |     not_clone.clone();
+   |               ^^^^^ within `{async closure@$DIR/not-clone-closure.rs:29:21: 29:34}`, the trait `Clone` is not implemented for `NotClonableUpvar`, which is required by `{async closure@$DIR/not-clone-closure.rs:29:21: 29:34}: Clone`
+   |
+note: required because it's used within this closure
+  --> $DIR/not-clone-closure.rs:29:21
+   |
+LL |     let not_clone = async move || {
+   |                     ^^^^^^^^^^^^^
+help: consider annotating `NotClonableUpvar` with `#[derive(Clone)]`
+   |
+LL + #[derive(Clone)]
+LL | struct NotClonableUpvar;
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
index 17681161e20..18f16ca4b2d 100644
--- a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
+++ b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
@@ -19,7 +19,7 @@ fn simple<'a>(x: &'a i32) {
 
     let c = async move || { println!("{}", *x); };
     outlives::<'a>(c()); //~ ERROR `c` does not live long enough
-    outlives::<'a>(call_once(c)); //~ ERROR cannot move out of `c`
+    outlives::<'a>(call_once(c));
 }
 
 struct S<'a>(&'a i32);
diff --git a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
index 569028934cb..1df5abdbb18 100644
--- a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
+++ b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
@@ -29,22 +29,6 @@ LL |     outlives::<'a>(call_once(c));
 LL | }
    | - `c` dropped here while still borrowed
 
-error[E0505]: cannot move out of `c` because it is borrowed
-  --> $DIR/without-precise-captures-we-are-powerless.rs:22:30
-   |
-LL | fn simple<'a>(x: &'a i32) {
-   |           -- lifetime `'a` defined here
-...
-LL |     let c = async move || { println!("{}", *x); };
-   |         - binding `c` declared here
-LL |     outlives::<'a>(c());
-   |                    ---
-   |                    |
-   |                    borrow of `c` occurs here
-   |                    argument requires that `c` is borrowed for `'a`
-LL |     outlives::<'a>(call_once(c));
-   |                              ^ move out of `c` occurs here
-
 error[E0597]: `x` does not live long enough
   --> $DIR/without-precise-captures-we-are-powerless.rs:28:13
    |
@@ -146,7 +130,7 @@ LL |     // outlives::<'a>(call_once(c)); // FIXME(async_closures): Figure out w
 LL | }
    | - `c` dropped here while still borrowed
 
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
 Some errors have detailed explanations: E0505, E0597, E0621.
 For more information about an error, try `rustc --explain E0505`.
diff --git a/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.neg.stderr b/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.neg.stderr
new file mode 100644
index 00000000000..fa12dd14753
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.neg.stderr
@@ -0,0 +1,63 @@
+error[E0277]: the trait bound `String: Copy` is not satisfied
+  --> $DIR/type-alias-bounds.rs:23:12
+   |
+LL |     let _: AliasConstUnused<String>;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
+   |
+note: required by a bound in `ct_unused_0::AliasConstUnused`
+  --> $DIR/type-alias-bounds.rs:20:30
+   |
+LL |     type AliasConstUnused<T: Copy> = (T, I32<{ DATA }>);
+   |                              ^^^^ required by this bound in `AliasConstUnused`
+
+error[E0277]: the trait bound `String: Copy` is not satisfied
+  --> $DIR/type-alias-bounds.rs:31:12
+   |
+LL |     let _: AliasConstUnused;
+   |            ^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
+   |
+note: required by a bound in `ct_unused_1::AliasConstUnused`
+  --> $DIR/type-alias-bounds.rs:29:41
+   |
+LL |     type AliasConstUnused where String: Copy = I32<{ 0; 0 }>;
+   |                                         ^^^^ required by this bound in `AliasConstUnused`
+
+error[E0277]: the trait bound `String: Copy` is not satisfied
+  --> $DIR/type-alias-bounds.rs:39:12
+   |
+LL |     let _: AliasFnUnused<String>;
+   |            ^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
+   |
+note: required by a bound in `AliasFnUnused`
+  --> $DIR/type-alias-bounds.rs:36:27
+   |
+LL |     type AliasFnUnused<T: Copy> = (T, I32<{ code() }>);
+   |                           ^^^^ required by this bound in `AliasFnUnused`
+
+error[E0277]: the trait bound `String: Copy` is not satisfied
+  --> $DIR/type-alias-bounds.rs:57:12
+   |
+LL |     let _: AliasAssocConstUsed<String>;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
+   |
+note: required by a bound in `AliasAssocConstUsed`
+  --> $DIR/type-alias-bounds.rs:55:41
+   |
+LL |     type AliasAssocConstUsed<T: Trait + Copy> = I32<{ T::DATA }>;
+   |                                         ^^^^ required by this bound in `AliasAssocConstUsed`
+
+error[E0277]: the trait bound `String: Copy` is not satisfied
+  --> $DIR/type-alias-bounds.rs:65:12
+   |
+LL |     let _: AliasFnUsed<String>;
+   |            ^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
+   |
+note: required by a bound in `AliasFnUsed`
+  --> $DIR/type-alias-bounds.rs:62:33
+   |
+LL |     type AliasFnUsed<T: Trait + Copy> = I32<{ code::<T>() }>;
+   |                                 ^^^^ required by this bound in `AliasFnUsed`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.rs b/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.rs
new file mode 100644
index 00000000000..f16e646129c
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/type-alias-bounds.rs
@@ -0,0 +1,71 @@
+//@ revisions: pos neg
+//@[pos] check-pass
+
+#![feature(generic_const_exprs)]
+#![feature(trivial_bounds)] // only used in test case `ct_unused_1`
+#![allow(incomplete_features)]
+
+// FIXME(generic_const_exprs): Revisit this before stabilization.
+// Check that we don't emit the lint `type_alias_bounds` for (eager) type aliases
+// whose RHS contains a const projection (aka uneval'ed const).
+// Since anon consts inherit the parent generics and predicates and we effectively
+// check them before and after instantiaton for well-formedness, the type alias
+// bounds are in every sense "enforced".
+// Note that the test cases whose name ends in "unused" just demonstrate that this
+// holds even if the const projections don't "visibly" capture any generics and/or
+// predicates.
+#![deny(type_alias_bounds)]
+
+fn ct_unused_0() {
+    type AliasConstUnused<T: Copy> = (T, I32<{ DATA }>);
+    const DATA: i32 = 0;
+    #[cfg(neg)]
+    let _: AliasConstUnused<String>;
+    //[neg]~^ ERROR the trait bound `String: Copy` is not satisfied
+}
+
+fn ct_unused_1() {
+    #[allow(trivial_bounds)]
+    type AliasConstUnused where String: Copy = I32<{ 0; 0 }>;
+    #[cfg(neg)]
+    let _: AliasConstUnused;
+    //[neg]~^ ERROR the trait bound `String: Copy` is not satisfied
+}
+
+fn fn_unused() {
+    type AliasFnUnused<T: Copy> = (T, I32<{ code() }>);
+    const fn code() -> i32 { 0 }
+    #[cfg(neg)]
+    let _: AliasFnUnused<String>;
+    //[neg]~^ ERROR the trait bound `String: Copy` is not satisfied
+}
+
+trait Trait {
+    type Proj;
+    const DATA: i32;
+}
+
+impl Trait for String {
+    type Proj = i32;
+    const DATA: i32 = 0;
+}
+
+// Regression test for issue #94398.
+fn assoc_ct_used() {
+    type AliasAssocConstUsed<T: Trait + Copy> = I32<{ T::DATA }>;
+    #[cfg(neg)]
+    let _: AliasAssocConstUsed<String>;
+    //[neg]~^ ERROR the trait bound `String: Copy` is not satisfied
+}
+
+fn fn_used() {
+    type AliasFnUsed<T: Trait + Copy> = I32<{ code::<T>() }>;
+    const fn code<T: Trait>() -> i32 { T::DATA }
+    #[cfg(neg)]
+    let _: AliasFnUsed<String>;
+    //[neg]~^ ERROR the trait bound `String: Copy` is not satisfied
+}
+
+struct I32<const N: i32>;
+
+fn main() {}
diff --git a/tests/ui/consts/const-eval/parse_ints.rs b/tests/ui/consts/const-eval/parse_ints.rs
index ff9fc47e65c..cb9a3eb4312 100644
--- a/tests/ui/consts/const-eval/parse_ints.rs
+++ b/tests/ui/consts/const-eval/parse_ints.rs
@@ -1,5 +1,3 @@
-#![feature(const_int_from_str)]
-
 const _OK: () = match i32::from_str_radix("-1234", 10) {
     Ok(x) => assert!(x == -1234),
     Err(_) => panic!(),
diff --git a/tests/ui/consts/const-eval/parse_ints.stderr b/tests/ui/consts/const-eval/parse_ints.stderr
index 9e49fe433a1..ec9249ece8e 100644
--- a/tests/ui/consts/const-eval/parse_ints.stderr
+++ b/tests/ui/consts/const-eval/parse_ints.stderr
@@ -6,7 +6,7 @@ error[E0080]: evaluation of constant value failed
 note: inside `core::num::<impl u64>::from_str_radix`
   --> $SRC_DIR/core/src/num/mod.rs:LL:COL
 note: inside `_TOO_LOW`
-  --> $DIR/parse_ints.rs:7:24
+  --> $DIR/parse_ints.rs:5:24
    |
 LL | const _TOO_LOW: () = { u64::from_str_radix("12345ABCD", 1); };
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -20,7 +20,7 @@ error[E0080]: evaluation of constant value failed
 note: inside `core::num::<impl u64>::from_str_radix`
   --> $SRC_DIR/core/src/num/mod.rs:LL:COL
 note: inside `_TOO_HIGH`
-  --> $DIR/parse_ints.rs:8:25
+  --> $DIR/parse_ints.rs:6:25
    |
 LL | const _TOO_HIGH: () = { u64::from_str_radix("12345ABCD", 37); };
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs
new file mode 100644
index 00000000000..debe143b091
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs
@@ -0,0 +1,24 @@
+#![feature(auto_traits)]
+
+trait Trait1 {}
+auto trait Trait2 {}
+trait Trait3: ?Trait1 {}
+//~^  ERROR `?Trait` is not permitted in supertraits
+trait Trait4 where Self: ?Trait1 {}
+//~^ ERROR ?Trait` bounds are only permitted at the point where a type parameter is declared
+
+fn foo(_: Box<dyn Trait1 + ?Trait2>) {}
+//~^  ERROR `?Trait` is not permitted in trait object types
+fn bar<T: ?Trait1 + ?Trait2>(_: T) {}
+//~^ ERROR type parameter has more than one relaxed default bound, only one is supported
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+
+trait Trait {}
+// Do not suggest `#![feature(more_maybe_bounds)]` for repetitions
+fn baz<T: ?Trait + ?Trait>(_ : T) {}
+//~^ ERROR type parameter has more than one relaxed default bound, only one is supported
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+
+fn main() {}
diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr
new file mode 100644
index 00000000000..e6d65e05997
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr
@@ -0,0 +1,71 @@
+error[E0658]: `?Trait` is not permitted in supertraits
+  --> $DIR/feature-gate-more-maybe-bounds.rs:5:15
+   |
+LL | trait Trait3: ?Trait1 {}
+   |               ^^^^^^^
+   |
+   = note: traits are `?Trait1` by default
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `?Trait` is not permitted in trait object types
+  --> $DIR/feature-gate-more-maybe-bounds.rs:10:28
+   |
+LL | fn foo(_: Box<dyn Trait1 + ?Trait2>) {}
+   |                            ^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
+  --> $DIR/feature-gate-more-maybe-bounds.rs:7:26
+   |
+LL | trait Trait4 where Self: ?Trait1 {}
+   |                          ^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0203]: type parameter has more than one relaxed default bound, only one is supported
+  --> $DIR/feature-gate-more-maybe-bounds.rs:12:11
+   |
+LL | fn bar<T: ?Trait1 + ?Trait2>(_: T) {}
+   |           ^^^^^^^   ^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/feature-gate-more-maybe-bounds.rs:12:11
+   |
+LL | fn bar<T: ?Trait1 + ?Trait2>(_: T) {}
+   |           ^^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/feature-gate-more-maybe-bounds.rs:12:21
+   |
+LL | fn bar<T: ?Trait1 + ?Trait2>(_: T) {}
+   |                     ^^^^^^^
+
+error[E0203]: type parameter has more than one relaxed default bound, only one is supported
+  --> $DIR/feature-gate-more-maybe-bounds.rs:19:11
+   |
+LL | fn baz<T: ?Trait + ?Trait>(_ : T) {}
+   |           ^^^^^^   ^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/feature-gate-more-maybe-bounds.rs:19:11
+   |
+LL | fn baz<T: ?Trait + ?Trait>(_ : T) {}
+   |           ^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/feature-gate-more-maybe-bounds.rs:19:20
+   |
+LL | fn baz<T: ?Trait + ?Trait>(_ : T) {}
+   |                    ^^^^^^
+
+error: aborting due to 5 previous errors; 4 warnings emitted
+
+Some errors have detailed explanations: E0203, E0658.
+For more information about an error, try `rustc --explain E0203`.
diff --git a/tests/ui/lang-items/missing-clone-for-suggestion.rs b/tests/ui/lang-items/missing-clone-for-suggestion.rs
deleted file mode 100644
index e8290c0098a..00000000000
--- a/tests/ui/lang-items/missing-clone-for-suggestion.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-// Avoid panicking if the Clone trait is not found while building error suggestions
-// See #104870
-
-#![feature(no_core, lang_items)]
-#![no_core]
-
-#[lang = "sized"]
-trait Sized {}
-
-#[lang = "copy"]
-trait Copy {}
-
-fn g<T>(x: T) {}
-
-fn f(x: *mut u8) {
-    g(x);
-    g(x); //~ ERROR use of moved value: `x`
-}
-
-fn main() {}
diff --git a/tests/ui/lang-items/missing-clone-for-suggestion.stderr b/tests/ui/lang-items/missing-clone-for-suggestion.stderr
deleted file mode 100644
index 0187f965b5c..00000000000
--- a/tests/ui/lang-items/missing-clone-for-suggestion.stderr
+++ /dev/null
@@ -1,21 +0,0 @@
-error[E0382]: use of moved value: `x`
-  --> $DIR/missing-clone-for-suggestion.rs:17:7
-   |
-LL | fn f(x: *mut u8) {
-   |      - move occurs because `x` has type `*mut u8`, which does not implement the `Copy` trait
-LL |     g(x);
-   |       - value moved here
-LL |     g(x);
-   |       ^ value used here after move
-   |
-note: consider changing this parameter type in function `g` to borrow instead if owning the value isn't necessary
-  --> $DIR/missing-clone-for-suggestion.rs:13:12
-   |
-LL | fn g<T>(x: T) {}
-   |    -       ^ this parameter takes ownership of the value
-   |    |
-   |    in this function
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0382`.
diff --git a/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs b/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs
new file mode 100644
index 00000000000..46065dcee81
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs
@@ -0,0 +1,45 @@
+#![deny(dead_code)]
+
+struct Foo; //~ ERROR struct `Foo` is never constructed
+
+trait Trait { //~ ERROR trait `Trait` is never used
+    fn foo(&self) {}
+}
+
+impl Trait for Foo {}
+
+impl Trait for [Foo] {}
+impl<const N: usize> Trait for [Foo; N] {}
+
+impl Trait for *const Foo {}
+impl Trait for *mut Foo {}
+
+impl Trait for &Foo {}
+impl Trait for &&Foo {}
+impl Trait for &mut Foo {}
+
+impl Trait for [&Foo] {}
+impl Trait for &[Foo] {}
+impl Trait for &*const Foo {}
+
+pub trait Trait2 {
+    fn foo(&self) {}
+}
+
+impl Trait2 for Foo {}
+
+impl Trait2 for [Foo] {}
+impl<const N: usize> Trait2 for [Foo; N] {}
+
+impl Trait2 for *const Foo {}
+impl Trait2 for *mut Foo {}
+
+impl Trait2 for &Foo {}
+impl Trait2 for &&Foo {}
+impl Trait2 for &mut Foo {}
+
+impl Trait2 for [&Foo] {}
+impl Trait2 for &[Foo] {}
+impl Trait2 for &*const Foo {}
+
+fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr b/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr
new file mode 100644
index 00000000000..e61fc403e81
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr
@@ -0,0 +1,20 @@
+error: struct `Foo` is never constructed
+  --> $DIR/unused-impl-for-non-adts.rs:3:8
+   |
+LL | struct Foo;
+   |        ^^^
+   |
+note: the lint level is defined here
+  --> $DIR/unused-impl-for-non-adts.rs:1:9
+   |
+LL | #![deny(dead_code)]
+   |         ^^^^^^^^^
+
+error: trait `Trait` is never used
+  --> $DIR/unused-impl-for-non-adts.rs:5:7
+   |
+LL | trait Trait {
+   |       ^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/macros/issue-118786.rs b/tests/ui/macros/issue-118786.rs
index 97454c9de07..a41372e4ea8 100644
--- a/tests/ui/macros/issue-118786.rs
+++ b/tests/ui/macros/issue-118786.rs
@@ -7,6 +7,7 @@ macro_rules! make_macro {
         macro_rules! $macro_name {
         //~^ ERROR macro expansion ignores token `{` and any following
         //~| ERROR cannot find macro `macro_rules` in this scope
+        //~| put a macro name here
             () => {}
         }
     }
diff --git a/tests/ui/macros/issue-118786.stderr b/tests/ui/macros/issue-118786.stderr
index 03e65c94ba7..256b742ee16 100644
--- a/tests/ui/macros/issue-118786.stderr
+++ b/tests/ui/macros/issue-118786.stderr
@@ -1,5 +1,5 @@
 error: macros that expand to items must be delimited with braces or followed by a semicolon
-  --> $DIR/issue-118786.rs:15:13
+  --> $DIR/issue-118786.rs:16:13
    |
 LL | make_macro!((meow));
    |             ^^^^^^
@@ -34,10 +34,10 @@ LL | make_macro!((meow));
    | ------------------- in this macro invocation
    |
 note: maybe you have forgotten to define a name for this `macro_rules!`
-  --> $DIR/issue-118786.rs:7:9
+  --> $DIR/issue-118786.rs:7:20
    |
 LL |         macro_rules! $macro_name {
-   |         ^^^^^^^^^^^
+   |                    ^ put a macro name here
 ...
 LL | make_macro!((meow));
    | ------------------- in this macro invocation
diff --git a/tests/ui/maybe-bounds.stderr b/tests/ui/maybe-bounds.stderr
index 1d823b6acb2..230d11fd0ae 100644
--- a/tests/ui/maybe-bounds.stderr
+++ b/tests/ui/maybe-bounds.stderr
@@ -1,22 +1,31 @@
-error: `?Trait` is not permitted in supertraits
+error[E0658]: `?Trait` is not permitted in supertraits
   --> $DIR/maybe-bounds.rs:1:11
    |
 LL | trait Tr: ?Sized {}
    |           ^^^^^^
    |
    = note: traits are `?Sized` by default
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bounds.rs:4:20
    |
 LL | type A1 = dyn Tr + (?Sized);
    |                    ^^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bounds.rs:6:28
    |
 LL | type A2 = dyn for<'a> Tr + (?Sized);
    |                            ^^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/parser/issues/issue-19398.rs b/tests/ui/parser/issues/issue-19398.rs
index 46eb320a172..358f65f1da5 100644
--- a/tests/ui/parser/issues/issue-19398.rs
+++ b/tests/ui/parser/issues/issue-19398.rs
@@ -1,6 +1,10 @@
 trait T {
     extern "Rust" unsafe fn foo();
-    //~^ ERROR expected `{`, found keyword `unsafe`
+    //~^ ERROR expected `fn`, found keyword `unsafe`
+    //~| NOTE expected `fn`
+    //~| HELP `unsafe` must come before `extern "Rust"`
+    //~| SUGGESTION unsafe extern "Rust"
+    //~| NOTE keyword order for functions declaration is `pub`, `default`, `const`, `async`, `unsafe`, `extern`
 }
 
 fn main() {}
diff --git a/tests/ui/parser/issues/issue-19398.stderr b/tests/ui/parser/issues/issue-19398.stderr
index 236fac673b6..2b97ec50c91 100644
--- a/tests/ui/parser/issues/issue-19398.stderr
+++ b/tests/ui/parser/issues/issue-19398.stderr
@@ -1,13 +1,13 @@
-error: expected `{`, found keyword `unsafe`
+error: expected `fn`, found keyword `unsafe`
   --> $DIR/issue-19398.rs:2:19
    |
-LL | trait T {
-   |         - while parsing this item list starting here
 LL |     extern "Rust" unsafe fn foo();
-   |                   ^^^^^^ expected `{`
-LL |
-LL | }
-   | - the item list ends here
+   |     --------------^^^^^^
+   |     |             |
+   |     |             expected `fn`
+   |     help: `unsafe` must come before `extern "Rust"`: `unsafe extern "Rust"`
+   |
+   = note: keyword order for functions declaration is `pub`, `default`, `const`, `async`, `unsafe`, `extern`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.rs b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.rs
new file mode 100644
index 00000000000..794ac635c76
--- /dev/null
+++ b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.rs
@@ -0,0 +1,16 @@
+//@ edition:2018
+
+// There is an order to respect for keywords before a function:
+// `<visibility>, const, async, unsafe, extern, "<ABI>"`
+//
+// This test ensures the compiler is helpful about them being misplaced.
+// Visibilities are tested elsewhere.
+
+extern "C" unsafe fn test() {}
+//~^ ERROR expected `fn`, found keyword `unsafe`
+//~| NOTE expected `fn`
+//~| HELP `unsafe` must come before `extern "C"`
+//~| SUGGESTION unsafe extern "C"
+//~| NOTE keyword order for functions declaration is `pub`, `default`, `const`, `async`, `unsafe`, `extern`
+
+fn main() {}
diff --git a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.stderr b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.stderr
new file mode 100644
index 00000000000..8ed037869c8
--- /dev/null
+++ b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe-abi.stderr
@@ -0,0 +1,13 @@
+error: expected `fn`, found keyword `unsafe`
+  --> $DIR/wrong-unsafe-abi.rs:9:12
+   |
+LL | extern "C" unsafe fn test() {}
+   | -----------^^^^^^
+   | |          |
+   | |          expected `fn`
+   | help: `unsafe` must come before `extern "C"`: `unsafe extern "C"`
+   |
+   = note: keyword order for functions declaration is `pub`, `default`, `const`, `async`, `unsafe`, `extern`
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/parser/trait-object-trait-parens.stderr b/tests/ui/parser/trait-object-trait-parens.stderr
index 3134746b930..ff32b173d49 100644
--- a/tests/ui/parser/trait-object-trait-parens.stderr
+++ b/tests/ui/parser/trait-object-trait-parens.stderr
@@ -1,20 +1,29 @@
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/trait-object-trait-parens.rs:8:24
    |
 LL |     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
    |                        ^^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/trait-object-trait-parens.rs:13:16
    |
 LL |     let _: Box<?Sized + (for<'a> Trait<'a>) + (Obj)>;
    |                ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/trait-object-trait-parens.rs:18:44
    |
 LL |     let _: Box<for<'a> Trait<'a> + (Obj) + (?Sized)>;
    |                                            ^^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/trait-object-trait-parens.rs:8:16
@@ -91,4 +100,5 @@ LL |     let _: Box<for<'a> Trait<'a> + (Obj) + (?Sized)>;
 
 error: aborting due to 6 previous errors; 3 warnings emitted
 
-For more information about this error, try `rustc --explain E0225`.
+Some errors have detailed explanations: E0225, E0658.
+For more information about an error, try `rustc --explain E0225`.
diff --git a/tests/ui/privacy/private-in-public-warn.rs b/tests/ui/privacy/private-in-public-warn.rs
index 99d318e36be..746b98fbd07 100644
--- a/tests/ui/privacy/private-in-public-warn.rs
+++ b/tests/ui/privacy/private-in-public-warn.rs
@@ -39,7 +39,7 @@ mod traits {
     pub trait PubTr {}
 
     pub type Alias<T: PrivTr> = T; //~ ERROR trait `traits::PrivTr` is more private than the item `traits::Alias`
-    //~^ WARNING bounds on generic parameters are not enforced in type aliases
+    //~^ WARNING bounds on generic parameters in type aliases are not enforced
     pub trait Tr1: PrivTr {} //~ ERROR trait `traits::PrivTr` is more private than the item `traits::Tr1`
     pub trait Tr2<T: PrivTr> {} //~ ERROR trait `traits::PrivTr` is more private than the item `traits::Tr2`
     pub trait Tr3 {
@@ -58,7 +58,7 @@ mod traits_where {
 
     pub type Alias<T> where T: PrivTr = T;
         //~^ ERROR trait `traits_where::PrivTr` is more private than the item `traits_where::Alias`
-        //~| WARNING where clauses are not enforced in type aliases
+        //~| WARNING where clauses on type aliases are not enforced
     pub trait Tr2<T> where T: PrivTr {}
         //~^ ERROR trait `traits_where::PrivTr` is more private than the item `traits_where::Tr2`
     pub trait Tr3 {
diff --git a/tests/ui/privacy/private-in-public-warn.stderr b/tests/ui/privacy/private-in-public-warn.stderr
index ac7e5547de9..3f7b8c281e7 100644
--- a/tests/ui/privacy/private-in-public-warn.stderr
+++ b/tests/ui/privacy/private-in-public-warn.stderr
@@ -395,30 +395,32 @@ note: but type `Priv2` is only usable at visibility `pub(self)`
 LL |     struct Priv2;
    |     ^^^^^^^^^^^^
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/private-in-public-warn.rs:41:23
    |
 LL |     pub type Alias<T: PrivTr> = T;
-   |                       ^^^^^^
-   |
+   |                     --^^^^^^
+   |                     | |
+   |                     | will not be checked at usage sites of the type alias
+   |                     help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
    = note: `#[warn(type_alias_bounds)]` on by default
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL -     pub type Alias<T: PrivTr> = T;
-LL +     pub type Alias<T> = T;
-   |
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/private-in-public-warn.rs:59:29
    |
 LL |     pub type Alias<T> where T: PrivTr = T;
-   |                             ^^^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL -     pub type Alias<T> where T: PrivTr = T;
-LL +     pub type Alias<T>  = T;
-   |
+   |                       ------^^^^^^^^^
+   |                       |     |
+   |                       |     will not be checked at usage sites of the type alias
+   |                       help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
 error: aborting due to 34 previous errors; 2 warnings emitted
 
diff --git a/tests/ui/resolve/issue-118295.rs b/tests/ui/resolve/issue-118295.rs
index b97681d9563..37a49baee80 100644
--- a/tests/ui/resolve/issue-118295.rs
+++ b/tests/ui/resolve/issue-118295.rs
@@ -1,5 +1,11 @@
 macro_rules! {}
 //~^ ERROR cannot find macro `macro_rules` in this scope
 //~| NOTE maybe you have forgotten to define a name for this `macro_rules!`
+//~| put a macro name here
+
+macro_rules!{}
+//~^ ERROR cannot find macro `macro_rules` in this scope
+//~| NOTE maybe you have forgotten to define a name for this `macro_rules!`
+//~| put a macro name here
 
 fn main() {}
diff --git a/tests/ui/resolve/issue-118295.stderr b/tests/ui/resolve/issue-118295.stderr
index d60d7d9185d..06a37e81d6c 100644
--- a/tests/ui/resolve/issue-118295.stderr
+++ b/tests/ui/resolve/issue-118295.stderr
@@ -1,14 +1,26 @@
 error: cannot find macro `macro_rules` in this scope
-  --> $DIR/issue-118295.rs:1:1
+  --> $DIR/issue-118295.rs:6:1
    |
-LL | macro_rules! {}
+LL | macro_rules!{}
    | ^^^^^^^^^^^
    |
 note: maybe you have forgotten to define a name for this `macro_rules!`
+  --> $DIR/issue-118295.rs:6:12
+   |
+LL | macro_rules!{}
+   |            ^ put a macro name here
+
+error: cannot find macro `macro_rules` in this scope
   --> $DIR/issue-118295.rs:1:1
    |
 LL | macro_rules! {}
    | ^^^^^^^^^^^
+   |
+note: maybe you have forgotten to define a name for this `macro_rules!`
+  --> $DIR/issue-118295.rs:1:12
+   |
+LL | macro_rules! {}
+   |            ^ put a macro name here
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
diff --git a/tests/ui/resolve/issue-55673.stderr b/tests/ui/resolve/issue-55673.stderr
index ffc3252230a..4069b35a998 100644
--- a/tests/ui/resolve/issue-55673.stderr
+++ b/tests/ui/resolve/issue-55673.stderr
@@ -19,7 +19,7 @@ help: consider further restricting type parameter `T`
    |
 LL |     T::Baa: std::fmt::Debug, T: Foo
    |                            ~~~~~~~~
-help: and also change the associated type name
+help: ...and changing the associated type name
    |
 LL |     T::Bar: std::fmt::Debug,
    |        ~~~
diff --git a/tests/ui/traits/maybe-polarity-pass.rs b/tests/ui/traits/maybe-polarity-pass.rs
new file mode 100644
index 00000000000..075a0d8dcac
--- /dev/null
+++ b/tests/ui/traits/maybe-polarity-pass.rs
@@ -0,0 +1,27 @@
+//@ check-pass
+
+#![feature(auto_traits)]
+#![feature(more_maybe_bounds)]
+#![feature(negative_impls)]
+
+trait Trait1 {}
+auto trait Trait2 {}
+
+trait Trait3 : ?Trait1 {}
+trait Trait4 where Self: Trait1 {}
+
+fn foo(_: Box<(dyn Trait3 + ?Trait2)>) {}
+fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
+//~^ WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+
+struct S;
+impl !Trait2 for S {}
+impl Trait1 for S {}
+impl Trait3 for S {}
+
+fn main() {
+    foo(Box::new(S));
+    bar(&S);
+}
diff --git a/tests/ui/traits/maybe-polarity-pass.stderr b/tests/ui/traits/maybe-polarity-pass.stderr
new file mode 100644
index 00000000000..09ed52f5b0d
--- /dev/null
+++ b/tests/ui/traits/maybe-polarity-pass.stderr
@@ -0,0 +1,20 @@
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/maybe-polarity-pass.rs:14:20
+   |
+LL | fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
+   |                    ^^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/maybe-polarity-pass.rs:14:30
+   |
+LL | fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
+   |                              ^^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/maybe-polarity-pass.rs:14:40
+   |
+LL | fn bar<T: ?Sized + ?Trait2 + ?Trait1 + ?Trait4>(_: &T) {}
+   |                                        ^^^^^^^
+
+warning: 3 warnings emitted
+
diff --git a/tests/ui/traits/maybe-polarity-repeated.rs b/tests/ui/traits/maybe-polarity-repeated.rs
new file mode 100644
index 00000000000..4b5ec83fffa
--- /dev/null
+++ b/tests/ui/traits/maybe-polarity-repeated.rs
@@ -0,0 +1,9 @@
+#![feature(more_maybe_bounds)]
+
+trait Trait {}
+fn foo<T: ?Trait + ?Trait>(_: T) {}
+//~^ ERROR type parameter has more than one relaxed default bound, only one is supported
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+
+fn main() {}
diff --git a/tests/ui/traits/maybe-polarity-repeated.stderr b/tests/ui/traits/maybe-polarity-repeated.stderr
new file mode 100644
index 00000000000..610c484fbec
--- /dev/null
+++ b/tests/ui/traits/maybe-polarity-repeated.stderr
@@ -0,0 +1,21 @@
+error[E0203]: type parameter has more than one relaxed default bound, only one is supported
+  --> $DIR/maybe-polarity-repeated.rs:4:11
+   |
+LL | fn foo<T: ?Trait + ?Trait>(_: T) {}
+   |           ^^^^^^   ^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/maybe-polarity-repeated.rs:4:11
+   |
+LL | fn foo<T: ?Trait + ?Trait>(_: T) {}
+   |           ^^^^^^
+
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/maybe-polarity-repeated.rs:4:20
+   |
+LL | fn foo<T: ?Trait + ?Trait>(_: T) {}
+   |                    ^^^^^^
+
+error: aborting due to 1 previous error; 2 warnings emitted
+
+For more information about this error, try `rustc --explain E0203`.
diff --git a/tests/ui/traits/wf-object/maybe-bound.stderr b/tests/ui/traits/wf-object/maybe-bound.stderr
index 2fe3f0fc39f..be7afabd0d0 100644
--- a/tests/ui/traits/wf-object/maybe-bound.stderr
+++ b/tests/ui/traits/wf-object/maybe-bound.stderr
@@ -1,32 +1,48 @@
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bound.rs:5:15
    |
 LL | type _0 = dyn ?Sized + Foo;
    |               ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bound.rs:8:21
    |
 LL | type _1 = dyn Foo + ?Sized;
    |                     ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bound.rs:11:21
    |
 LL | type _2 = dyn Foo + ?Sized + ?Sized;
    |                     ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bound.rs:11:30
    |
 LL | type _2 = dyn Foo + ?Sized + ?Sized;
    |                              ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/maybe-bound.rs:15:15
    |
 LL | type _3 = dyn ?Sized + Foo;
    |               ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error: aborting due to 5 previous errors
 
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/traits/wf-object/only-maybe-bound.stderr b/tests/ui/traits/wf-object/only-maybe-bound.stderr
index cbc41feec1e..26269476eaa 100644
--- a/tests/ui/traits/wf-object/only-maybe-bound.stderr
+++ b/tests/ui/traits/wf-object/only-maybe-bound.stderr
@@ -1,8 +1,11 @@
-error: `?Trait` is not permitted in trait object types
+error[E0658]: `?Trait` is not permitted in trait object types
   --> $DIR/only-maybe-bound.rs:3:15
    |
 LL | type _0 = dyn ?Sized;
    |               ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0224]: at least one trait is required for an object type
   --> $DIR/only-maybe-bound.rs:3:11
@@ -12,4 +15,5 @@ LL | type _0 = dyn ?Sized;
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0224`.
+Some errors have detailed explanations: E0224, E0658.
+For more information about an error, try `rustc --explain E0224`.
diff --git a/tests/ui/trivial-bounds/trivial-bounds-inconsistent.stderr b/tests/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
index d66e468873b..0eae68bfcf0 100644
--- a/tests/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
+++ b/tests/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
@@ -24,18 +24,19 @@ warning: trait bound i32: Foo does not depend on any type or lifetime parameters
 LL | union U where i32: Foo { f: i32 }
    |                    ^^^
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/trivial-bounds-inconsistent.rs:22:14
    |
 LL | type Y where i32: Foo = ();
-   |              ^^^^^^^^
-   |
+   |        ------^^^^^^^^
+   |        |     |
+   |        |     will not be checked at usage sites of the type alias
+   |        help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
    = note: `#[warn(type_alias_bounds)]` on by default
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type Y where i32: Foo = ();
-LL + type Y  = ();
-   |
 
 warning: trait bound i32: Foo does not depend on any type or lifetime parameters
   --> $DIR/trivial-bounds-inconsistent.rs:22:19
diff --git a/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.eager.stderr b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.eager.stderr
new file mode 100644
index 00000000000..e891ff10fda
--- /dev/null
+++ b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.eager.stderr
@@ -0,0 +1,36 @@
+error[E0220]: associated type `Assoc` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:9:22
+   |
+LL | type AssocOf<T> = T::Assoc;
+   |                      ^^^^^ there is an associated type `Assoc` in the trait `Trait`
+   |
+help: consider fully qualifying the associated type
+   |
+LL | type AssocOf<T> = <T as Trait>::Assoc;
+   |                   +  +++++++++
+
+error[E0220]: associated type `Assok` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:13:22
+   |
+LL | type AssokOf<T> = T::Assok;
+   |                      ^^^^^ there is a similarly named associated type `Assoc` in the trait `Trait`
+   |
+help: consider fully qualifying and renaming the associated type
+   |
+LL | type AssokOf<T> = <T as Trait>::Assoc;
+   |                   +  +++++++++  ~~~~~
+
+error[E0220]: associated type `Proj` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:22:21
+   |
+LL | type ProjOf<T> = T::Proj;
+   |                     ^^^^ there is an associated type `Proj` in the trait `Parametrized`
+   |
+help: consider fully qualifying the associated type
+   |
+LL | type ProjOf<T> = <T as Parametrized</* 'a, T, N */>>::Proj;
+   |                  +  ++++++++++++++++++++++++++++++++
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.lazy.stderr b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.lazy.stderr
new file mode 100644
index 00000000000..96179a7b484
--- /dev/null
+++ b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.lazy.stderr
@@ -0,0 +1,40 @@
+error[E0220]: associated type `Assoc` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:9:22
+   |
+LL | type AssocOf<T> = T::Assoc;
+   |                      ^^^^^ there is an associated type `Assoc` in the trait `Trait`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | type AssocOf<T: Trait> = T::Assoc;
+   |               +++++++
+
+error[E0220]: associated type `Assok` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:13:22
+   |
+LL | type AssokOf<T> = T::Assok;
+   |                      ^^^^^ there is a similarly named associated type `Assoc` in the trait `Trait`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | type AssokOf<T: Trait> = T::Assok;
+   |               +++++++
+help: ...and changing the associated type name
+   |
+LL | type AssokOf<T> = T::Assoc;
+   |                      ~~~~~
+
+error[E0220]: associated type `Proj` not found for `T`
+  --> $DIR/unresolved-assoc-ty-suggest-trait.rs:22:21
+   |
+LL | type ProjOf<T> = T::Proj;
+   |                     ^^^^ there is an associated type `Proj` in the trait `Parametrized`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | type ProjOf<T: Parametrized</* 'a, T, N */>> = T::Proj;
+   |              ++++++++++++++++++++++++++++++
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.rs b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.rs
new file mode 100644
index 00000000000..2c8d448f308
--- /dev/null
+++ b/tests/ui/type-alias/unresolved-assoc-ty-suggest-trait.rs
@@ -0,0 +1,26 @@
+// Ensure that we don't suggest *type alias bounds* for **eager** type aliases.
+// issue: rust-lang/rust#125789
+
+//@ revisions: eager lazy
+#![cfg_attr(lazy, feature(lazy_type_alias), allow(incomplete_features))]
+
+trait Trait { type Assoc; }
+
+type AssocOf<T> = T::Assoc; //~ ERROR associated type `Assoc` not found for `T`
+//[eager]~^ HELP consider fully qualifying the associated type
+//[lazy]~| HELP consider restricting type parameter `T`
+
+type AssokOf<T> = T::Assok; //~ ERROR associated type `Assok` not found for `T`
+//[eager]~^ HELP consider fully qualifying and renaming the associated type
+//[lazy]~| HELP consider restricting type parameter `T`
+//[lazy]~| HELP and changing the associated type name
+
+trait Parametrized<'a, T, const N: usize> {
+    type Proj;
+}
+
+type ProjOf<T> = T::Proj; //~ ERROR associated type `Proj` not found for `T`
+//[eager]~^ HELP consider fully qualifying the associated type
+//[lazy]~| HELP consider restricting type parameter `T`
+
+fn main() {}
diff --git a/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.rs b/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.rs
index 5ee3c027f40..52e0887175d 100644
--- a/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.rs
+++ b/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.rs
@@ -3,6 +3,6 @@
 
 //@ check-pass
 pub type T<P: Send + Send + Send> = P;
-//~^ WARN bounds on generic parameters are not enforced in type aliases
+//~^ WARN bounds on generic parameters in type aliases are not enforced
 
 fn main() {}
diff --git a/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.stderr b/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.stderr
index 125ffbbb417..9fd0fe4913b 100644
--- a/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.stderr
+++ b/tests/ui/type/issue-67690-type-alias-bound-diagnostic-crash.stderr
@@ -1,15 +1,16 @@
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/issue-67690-type-alias-bound-diagnostic-crash.rs:5:15
    |
 LL | pub type T<P: Send + Send + Send> = P;
-   |               ^^^^   ^^^^   ^^^^
+   |             --^^^^---^^^^---^^^^
+   |             |               |
+   |             |               will not be checked at usage sites of the type alias
+   |             help: remove this bound
    |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
    = note: `#[warn(type_alias_bounds)]` on by default
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - pub type T<P: Send + Send + Send> = P;
-LL + pub type T<P> = P;
-   |
 
 warning: 1 warning emitted
 
diff --git a/tests/ui/type/type-alias-bounds.rs b/tests/ui/type/type-alias-bounds.rs
index 6d63c0c7e1b..37c073fe1f9 100644
--- a/tests/ui/type/type-alias-bounds.rs
+++ b/tests/ui/type/type-alias-bounds.rs
@@ -6,15 +6,15 @@
 use std::rc::Rc;
 
 type SVec<T: Send + Send> = Vec<T>;
-//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
+//~^ WARN bounds on generic parameters in type aliases are not enforced [type_alias_bounds]
 type S2Vec<T> where T: Send = Vec<T>;
-//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
+//~^ WARN where clauses on type aliases are not enforced [type_alias_bounds]
 type VVec<'b, 'a: 'b + 'b> = (&'b u32, Vec<&'a i32>);
-//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
+//~^ WARN bounds on generic parameters in type aliases are not enforced [type_alias_bounds]
 type WVec<'b, T: 'b + 'b> = (&'b u32, Vec<T>);
-//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
+//~^ WARN bounds on generic parameters in type aliases are not enforced [type_alias_bounds]
 type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
-//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
+//~^ WARN where clauses on type aliases are not enforced [type_alias_bounds]
 
 static STATIC: u32 = 0;
 
@@ -42,10 +42,11 @@ fn foo<'a>(y: &'a i32) {
 struct Sendable<T: Send>(T);
 type MySendable<T> = Sendable<T>; // no error here!
 
-// However, bounds *are* taken into account when accessing associated types
+// Bounds on type params do enable shorthand type alias paths.
+// However, that doesn't actually mean that they are properly enforced.
 trait Bound { type Assoc; }
-type T1<U: Bound> = U::Assoc; //~ WARN not enforced in type aliases
-type T2<U> where U: Bound = U::Assoc;  //~ WARN not enforced in type aliases
+type T1<U: Bound> = U::Assoc; //~ WARN are not enforced
+type T2<U> where U: Bound = U::Assoc;  //~ WARN are not enforced
 
 // This errors:
 // `type T3<U> = U::Assoc;`
@@ -53,7 +54,7 @@ type T2<U> where U: Bound = U::Assoc;  //~ WARN not enforced in type aliases
 type T4<U> = <U as Bound>::Assoc;
 
 // Make sure the help about associated types is not shown incorrectly
-type T5<U: Bound> = <U as Bound>::Assoc;  //~ WARN not enforced in type aliases
-type T6<U: Bound> = ::std::vec::Vec<U>;  //~ WARN not enforced in type aliases
+type T5<U: Bound> = <U as Bound>::Assoc;  //~ WARN are not enforced
+type T6<U: Bound> = ::std::vec::Vec<U>;  //~ WARN are not enforced
 
 fn main() {}
diff --git a/tests/ui/type/type-alias-bounds.stderr b/tests/ui/type/type-alias-bounds.stderr
index 92e573393c9..15c00901066 100644
--- a/tests/ui/type/type-alias-bounds.stderr
+++ b/tests/ui/type/type-alias-bounds.stderr
@@ -1,121 +1,132 @@
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias-bounds.rs:8:14
    |
 LL | type SVec<T: Send + Send> = Vec<T>;
-   |              ^^^^   ^^^^
-   |
+   |            --^^^^---^^^^
+   |            |        |
+   |            |        will not be checked at usage sites of the type alias
+   |            help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
    = note: `#[warn(type_alias_bounds)]` on by default
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type SVec<T: Send + Send> = Vec<T>;
-LL + type SVec<T> = Vec<T>;
-   |
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias-bounds.rs:10:21
    |
 LL | type S2Vec<T> where T: Send = Vec<T>;
-   |                     ^^^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type S2Vec<T> where T: Send = Vec<T>;
-LL + type S2Vec<T>  = Vec<T>;
-   |
+   |               ------^^^^^^^
+   |               |     |
+   |               |     will not be checked at usage sites of the type alias
+   |               help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias-bounds.rs:12:19
    |
 LL | type VVec<'b, 'a: 'b + 'b> = (&'b u32, Vec<&'a i32>);
-   |                   ^^   ^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type VVec<'b, 'a: 'b + 'b> = (&'b u32, Vec<&'a i32>);
-LL + type VVec<'b, 'a> = (&'b u32, Vec<&'a i32>);
-   |
+   |                 --^^---^^
+   |                 |      |
+   |                 |      will not be checked at usage sites of the type alias
+   |                 help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
+warning: bounds on generic parameters in type aliases are not enforced
   --> $DIR/type-alias-bounds.rs:14:18
    |
 LL | type WVec<'b, T: 'b + 'b> = (&'b u32, Vec<T>);
-   |                  ^^   ^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type WVec<'b, T: 'b + 'b> = (&'b u32, Vec<T>);
-LL + type WVec<'b, T> = (&'b u32, Vec<T>);
-   |
+   |                --^^---^^
+   |                |      |
+   |                |      will not be checked at usage sites of the type alias
+   |                help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: where clauses are not enforced in type aliases
+warning: where clauses on type aliases are not enforced
   --> $DIR/type-alias-bounds.rs:16:25
    |
 LL | type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
-   |                         ^^^^^  ^^^^^
-   |
-help: the clause will not be checked when the type alias is used, and should be removed
-   |
-LL - type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
-LL + type W2Vec<'b, T>  = (&'b u32, Vec<T>);
-   |
+   |                   ------^^^^^--^^^^^
+   |                   |            |
+   |                   |            will not be checked at usage sites of the type alias
+   |                   help: remove this where clause
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
-  --> $DIR/type-alias-bounds.rs:47:12
+warning: bounds on generic parameters in type aliases are not enforced
+  --> $DIR/type-alias-bounds.rs:48:12
    |
 LL | type T1<U: Bound> = U::Assoc;
-   |            ^^^^^
+   |            ^^^^^ will not be checked at usage sites of the type alias
    |
-help: use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to associated types in type aliases
-  --> $DIR/type-alias-bounds.rs:47:21
-   |
-LL | type T1<U: Bound> = U::Assoc;
-   |                     ^^^^^^^^
-help: the bound will not be checked when the type alias is used, and should be removed
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
+help: remove this bound
    |
 LL - type T1<U: Bound> = U::Assoc;
 LL + type T1<U> = U::Assoc;
    |
+help: fully qualify this associated type
+   |
+LL | type T1<U: Bound> = <U as /* Trait */>::Assoc;
+   |                     +  +++++++++++++++
 
-warning: where clauses are not enforced in type aliases
-  --> $DIR/type-alias-bounds.rs:48:18
+warning: where clauses on type aliases are not enforced
+  --> $DIR/type-alias-bounds.rs:49:18
    |
 LL | type T2<U> where U: Bound = U::Assoc;
-   |                  ^^^^^^^^
+   |                  ^^^^^^^^ will not be checked at usage sites of the type alias
    |
-help: use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to associated types in type aliases
-  --> $DIR/type-alias-bounds.rs:48:29
-   |
-LL | type T2<U> where U: Bound = U::Assoc;
-   |                             ^^^^^^^^
-help: the clause will not be checked when the type alias is used, and should be removed
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
+help: remove this where clause
    |
 LL - type T2<U> where U: Bound = U::Assoc;
 LL + type T2<U>  = U::Assoc;
    |
+help: fully qualify this associated type
+   |
+LL | type T2<U> where U: Bound = <U as /* Trait */>::Assoc;
+   |                             +  +++++++++++++++
 
-warning: bounds on generic parameters are not enforced in type aliases
-  --> $DIR/type-alias-bounds.rs:56:12
+warning: bounds on generic parameters in type aliases are not enforced
+  --> $DIR/type-alias-bounds.rs:57:12
    |
 LL | type T5<U: Bound> = <U as Bound>::Assoc;
-   |            ^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type T5<U: Bound> = <U as Bound>::Assoc;
-LL + type T5<U> = <U as Bound>::Assoc;
-   |
+   |          --^^^^^
+   |          | |
+   |          | will not be checked at usage sites of the type alias
+   |          help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
-warning: bounds on generic parameters are not enforced in type aliases
-  --> $DIR/type-alias-bounds.rs:57:12
+warning: bounds on generic parameters in type aliases are not enforced
+  --> $DIR/type-alias-bounds.rs:58:12
    |
 LL | type T6<U: Bound> = ::std::vec::Vec<U>;
-   |            ^^^^^
-   |
-help: the bound will not be checked when the type alias is used, and should be removed
-   |
-LL - type T6<U: Bound> = ::std::vec::Vec<U>;
-LL + type T6<U> = ::std::vec::Vec<U>;
-   |
+   |          --^^^^^
+   |          | |
+   |          | will not be checked at usage sites of the type alias
+   |          help: remove this bound
+   |
+   = note: this is a known limitation of the type checker that may be lifted in a future edition.
+           see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+   = help: add `#![feature(lazy_type_alias)]` to the crate attributes to enable the desired semantics
 
 warning: 9 warnings emitted
 
diff --git a/tests/ui/unsized/maybe-bounds-where.stderr b/tests/ui/unsized/maybe-bounds-where.stderr
index 683bd387bb2..f7851261667 100644
--- a/tests/ui/unsized/maybe-bounds-where.stderr
+++ b/tests/ui/unsized/maybe-bounds-where.stderr
@@ -1,32 +1,47 @@
-error: `?Trait` bounds are only permitted at the point where a type parameter is declared
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
   --> $DIR/maybe-bounds-where.rs:1:28
    |
 LL | struct S1<T>(T) where (T): ?Sized;
    |                            ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` bounds are only permitted at the point where a type parameter is declared
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
   --> $DIR/maybe-bounds-where.rs:4:27
    |
 LL | struct S2<T>(T) where u8: ?Sized;
    |                           ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` bounds are only permitted at the point where a type parameter is declared
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
   --> $DIR/maybe-bounds-where.rs:7:35
    |
 LL | struct S3<T>(T) where &'static T: ?Sized;
    |                                   ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` bounds are only permitted at the point where a type parameter is declared
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
   --> $DIR/maybe-bounds-where.rs:12:34
    |
 LL | struct S4<T>(T) where for<'a> T: ?Trait<'a>;
    |                                  ^^^^^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: `?Trait` bounds are only permitted at the point where a type parameter is declared
+error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared
   --> $DIR/maybe-bounds-where.rs:21:21
    |
 LL |     fn f() where T: ?Sized {}
    |                     ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
   --> $DIR/maybe-bounds-where.rs:12:34
@@ -39,6 +54,9 @@ error[E0203]: type parameter has more than one relaxed default bound, only one i
    |
 LL | struct S5<T>(*const T) where T: ?Trait<'static> + ?Sized;
    |                                 ^^^^^^^^^^^^^^^   ^^^^^^
+   |
+   = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
   --> $DIR/maybe-bounds-where.rs:16:33
@@ -48,4 +66,5 @@ LL | struct S5<T>(*const T) where T: ?Trait<'static> + ?Sized;
 
 error: aborting due to 6 previous errors; 2 warnings emitted
 
-For more information about this error, try `rustc --explain E0203`.
+Some errors have detailed explanations: E0203, E0658.
+For more information about an error, try `rustc --explain E0203`.