Merging upstream version 1.69.0+dfsg1.

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

25 files changed, 142 insertions, 24 deletions

diff --git a/tests/ui/regions/do-not-suggest-adding-bound-to-opaque-type.stderr b/tests/ui/regions/do-not-suggest-adding-bound-to-opaque-type.stderr
index 6ea238f30..d76a83b02 100644
--- a/tests/ui/regions/do-not-suggest-adding-bound-to-opaque-type.stderr
+++ b/tests/ui/regions/do-not-suggest-adding-bound-to-opaque-type.stderr
@@ -1,6 +1,8 @@
 error[E0597]: `x` does not live long enough
   --> $DIR/do-not-suggest-adding-bound-to-opaque-type.rs:9:7
    |
+LL |     let x = ();
+   |         - binding `x` declared here
 LL |     S(&x)
    |     --^^-
    |     | |
diff --git a/tests/ui/regions/higher-ranked-implied.rs b/tests/ui/regions/higher-ranked-implied.rs
new file mode 100644
index 000000000..103884c50
--- /dev/null
+++ b/tests/ui/regions/higher-ranked-implied.rs
@@ -0,0 +1,14 @@
+// FIXME: This test should pass as the first two fields add implied bounds that
+// `'a` is equal to `'b` while the last one should simply use that fact. With
+// the current implementation this errors. We have to be careful as implied bounds
+// are only sound if they're also correctly checked.
+
+struct Inv<T>(*mut T); // `T` is invariant.
+type A = for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'a ()>);
+type B = for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'b ()>);
+
+fn main() {
+    let x: A = |_, _, _| ();
+    let y: B = x; //~ ERROR mismatched types
+    let _: A = y; //~ ERROR mismatched types
+}
diff --git a/tests/ui/regions/higher-ranked-implied.stderr b/tests/ui/regions/higher-ranked-implied.stderr
new file mode 100644
index 000000000..9d80eacd7
--- /dev/null
+++ b/tests/ui/regions/higher-ranked-implied.stderr
@@ -0,0 +1,21 @@
+error[E0308]: mismatched types
+  --> $DIR/higher-ranked-implied.rs:12:16
+   |
+LL |     let y: B = x;
+   |                ^ one type is more general than the other
+   |
+   = note: expected fn pointer `for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'b ()>)`
+              found fn pointer `for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'a ()>)`
+
+error[E0308]: mismatched types
+  --> $DIR/higher-ranked-implied.rs:13:16
+   |
+LL |     let _: A = y;
+   |                ^ one type is more general than the other
+   |
+   = note: expected fn pointer `for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'a ()>)`
+              found fn pointer `for<'a, 'b> fn(Inv<&'a &'b ()>, Inv<&'b &'a ()>, Inv<&'b ()>)`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/regions/issue-102374.stderr b/tests/ui/regions/issue-102374.stderr
index 157850693..af64b6867 100644
--- a/tests/ui/regions/issue-102374.stderr
+++ b/tests/ui/regions/issue-102374.stderr
@@ -7,7 +7,7 @@ LL |     f
    |     ^ expected `i32`, found fn pointer
    |
    = note:    expected type `i32`
-           found fn pointer `for<'z1, 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, 'k, 'l, 'm, 'n, 'o, 'p, 'q, 'r, 's, 't, 'u, 'v, 'w, 'x, 'y, 'z, 'z0> fn(Cell<...>)`
+           found fn pointer `fn(Cell<...>)`
            the full type name has been written to '$TEST_BUILD_DIR/regions/issue-102374/issue-102374.long-type-hash.txt'
 
 error: aborting due to previous error
diff --git a/tests/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr b/tests/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
index 3b62c7b61..bb5bc6f66 100644
--- a/tests/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
+++ b/tests/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
@@ -6,6 +6,7 @@ LL |     let _: fn(&mut &isize, &mut &isize) = a;
    |
    = note: expected fn pointer `for<'a, 'b, 'c, 'd> fn(&'a mut &'b isize, &'c mut &'d isize)`
                  found fn item `for<'a, 'b> fn(&'a mut &isize, &'b mut &isize) {a::<'_, '_>}`
+   = note: when the arguments and return types match, functions can be coerced to function pointers
 
 error: aborting due to previous error
 
diff --git a/tests/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr b/tests/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
index 8a18a234b..dbe9e9b1a 100644
--- a/tests/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
+++ b/tests/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
@@ -6,6 +6,7 @@ LL |     let _: fn(&mut &isize, &mut &isize, &mut &isize) = a;
    |
    = note: expected fn pointer `for<'a, 'b, 'c, 'd, 'e, 'f> fn(&'a mut &'b isize, &'c mut &'d isize, &'e mut &'f isize)`
                  found fn item `for<'a, 'b, 'c> fn(&'a mut &isize, &'b mut &isize, &'c mut &isize) {a::<'_, '_, '_>}`
+   = note: when the arguments and return types match, functions can be coerced to function pointers
 
 error: aborting due to previous error
 
diff --git a/tests/ui/regions/regions-addr-of-arg.stderr b/tests/ui/regions/regions-addr-of-arg.stderr
index e77289287..99060a9c7 100644
--- a/tests/ui/regions/regions-addr-of-arg.stderr
+++ b/tests/ui/regions/regions-addr-of-arg.stderr
@@ -1,6 +1,8 @@
 error[E0597]: `a` does not live long enough
   --> $DIR/regions-addr-of-arg.rs:5:30
    |
+LL | fn foo(a: isize) {
+   |        - binding `a` declared here
 LL |     let _p: &'static isize = &a;
    |             --------------   ^^ borrowed value does not live long enough
    |             |
diff --git a/tests/ui/regions/regions-early-bound-error-method.stderr b/tests/ui/regions/regions-early-bound-error-method.stderr
index 7f10c051f..a7746d898 100644
--- a/tests/ui/regions/regions-early-bound-error-method.stderr
+++ b/tests/ui/regions/regions-early-bound-error-method.stderr
@@ -6,7 +6,7 @@ LL | impl<'a> Box<'a> {
 LL |     fn or<'b,G:GetRef<'b>>(&self, g2: G) -> &'a isize {
    |           -- lifetime `'b` defined here
 LL |         g2.get()
-   |         ^^^^^^^^ associated function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
+   |         ^^^^^^^^ method was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
    |
    = help: consider adding the following bound: `'b: 'a`
 
diff --git a/tests/ui/regions/regions-fn-subtyping-return-static-fail.stderr b/tests/ui/regions/regions-fn-subtyping-return-static-fail.stderr
index 8d82ff958..766a3d033 100644
--- a/tests/ui/regions/regions-fn-subtyping-return-static-fail.stderr
+++ b/tests/ui/regions/regions-fn-subtyping-return-static-fail.stderr
@@ -8,6 +8,7 @@ LL |     want_G(baz);
    |
    = note: expected fn pointer `for<'cx> fn(&'cx S) -> &'static S`
                  found fn item `for<'a> fn(&'a S) -> &'a S {baz}`
+   = note: when the arguments and return types match, functions can be coerced to function pointers
 note: function defined here
   --> $DIR/regions-fn-subtyping-return-static-fail.rs:20:4
    |
diff --git a/tests/ui/regions/regions-free-region-ordering-caller1.stderr b/tests/ui/regions/regions-free-region-ordering-caller1.stderr
index 8ef7e2253..c83cfc1c9 100644
--- a/tests/ui/regions/regions-free-region-ordering-caller1.stderr
+++ b/tests/ui/regions/regions-free-region-ordering-caller1.stderr
@@ -18,6 +18,8 @@ error[E0597]: `y` does not live long enough
 LL | fn call1<'a>(x: &'a usize) {
    |          -- lifetime `'a` defined here
 ...
+LL |     let y: usize = 3;
+   |         - binding `y` declared here
 LL |     let z: &'a & usize = &(&y);
    |            -----------    ^^^^ borrowed value does not live long enough
    |            |
diff --git a/tests/ui/regions/regions-free-region-ordering-incorrect.stderr b/tests/ui/regions/regions-free-region-ordering-incorrect.stderr
index f7c75033c..d0ceaec3b 100644
--- a/tests/ui/regions/regions-free-region-ordering-incorrect.stderr
+++ b/tests/ui/regions/regions-free-region-ordering-incorrect.stderr
@@ -9,7 +9,7 @@ LL | /         match self.next {
 LL | |             Some(ref next) => next.get(),
 LL | |             None => &self.val
 LL | |         }
-   | |_________^ associated function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
+   | |_________^ method was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
    |
    = help: consider adding the following bound: `'a: 'b`
 
diff --git a/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.rs b/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.rs
index 7c2e1aeee..46462c432 100644
--- a/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.rs
+++ b/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.rs
@@ -8,6 +8,8 @@
 //
 //     'a : 'b
 
+#![warn(unused_lifetimes)]
+
 fn test<'a,'b>(x: &'a i32) -> &'b i32
     where 'a: 'static //~ WARN unnecessary lifetime parameter `'a`
 {
diff --git a/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.stderr b/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.stderr
index 70ed418d5..9f03a6553 100644
--- a/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.stderr
+++ b/tests/ui/regions/regions-free-region-outlives-static-outlives-free-region.stderr
@@ -1,10 +1,15 @@
 warning: unnecessary lifetime parameter `'a`
-  --> $DIR/regions-free-region-outlives-static-outlives-free-region.rs:12:11
+  --> $DIR/regions-free-region-outlives-static-outlives-free-region.rs:14:11
    |
 LL |     where 'a: 'static
    |           ^^
    |
    = help: you can use the `'static` lifetime directly, in place of `'a`
+note: the lint level is defined here
+  --> $DIR/regions-free-region-outlives-static-outlives-free-region.rs:11:9
+   |
+LL | #![warn(unused_lifetimes)]
+   |         ^^^^^^^^^^^^^^^^
 
 warning: 1 warning emitted
 
diff --git a/tests/ui/regions/regions-infer-proc-static-upvar.stderr b/tests/ui/regions/regions-infer-proc-static-upvar.stderr
index 803d0d744..c8a33bbc5 100644
--- a/tests/ui/regions/regions-infer-proc-static-upvar.stderr
+++ b/tests/ui/regions/regions-infer-proc-static-upvar.stderr
@@ -1,6 +1,8 @@
 error[E0597]: `x` does not live long enough
   --> $DIR/regions-infer-proc-static-upvar.rs:10:13
    |
+LL |       let x = 3;
+   |           - binding `x` declared here
 LL |       let y = &x;
    |               ^^ borrowed value does not live long enough
 LL | /     foo(move|| {
diff --git a/tests/ui/regions/regions-lifetime-bounds-on-fns.stderr b/tests/ui/regions/regions-lifetime-bounds-on-fns.stderr
index 17a901943..df0fd069e 100644
--- a/tests/ui/regions/regions-lifetime-bounds-on-fns.stderr
+++ b/tests/ui/regions/regions-lifetime-bounds-on-fns.stderr
@@ -6,6 +6,7 @@ LL |     let _: fn(&mut &isize, &mut &isize) = a;
    |
    = note: expected fn pointer `for<'a, 'b, 'c, 'd> fn(&'a mut &'b isize, &'c mut &'d isize)`
                  found fn item `for<'a, 'b> fn(&'a mut &isize, &'b mut &isize) {a::<'_, '_>}`
+   = note: when the arguments and return types match, functions can be coerced to function pointers
 
 error: aborting due to previous error
 
diff --git a/tests/ui/regions/regions-mock-codegen.rs b/tests/ui/regions/regions-mock-codegen.rs
index 9d0ca76e4..d5c93f81f 100644
--- a/tests/ui/regions/regions-mock-codegen.rs
+++ b/tests/ui/regions/regions-mock-codegen.rs
@@ -22,15 +22,15 @@ struct Ccx {
     x: isize,
 }
 
-fn allocate(_bcx: &arena) -> &Bcx<'_> {
+fn allocate(_bcx: &arena) -> &mut Bcx<'_> {
     unsafe {
         let layout = Layout::new::<Bcx>();
         let ptr = Global.allocate(layout).unwrap_or_else(|_| handle_alloc_error(layout));
-        &*(ptr.as_ptr() as *const _)
+        &mut *ptr.as_ptr().cast()
     }
 }
 
-fn h<'a>(bcx: &'a Bcx<'a>) -> &'a Bcx<'a> {
+fn h<'a>(bcx: &'a Bcx<'a>) -> &'a mut Bcx<'a> {
     return allocate(bcx.fcx.arena);
 }
 
@@ -38,7 +38,7 @@ fn g(fcx: &Fcx) {
     let bcx = Bcx { fcx };
     let bcx2 = h(&bcx);
     unsafe {
-        Global.deallocate(NonNull::new_unchecked(bcx2 as *const _ as *mut _), Layout::new::<Bcx>());
+        Global.deallocate(NonNull::new_unchecked(bcx2 as *mut _ as *mut _), Layout::new::<Bcx>());
     }
 }
 
diff --git a/tests/ui/regions/regions-nested-fns.stderr b/tests/ui/regions/regions-nested-fns.stderr
index bb2740310..ee43f9fa5 100644
--- a/tests/ui/regions/regions-nested-fns.stderr
+++ b/tests/ui/regions/regions-nested-fns.stderr
@@ -13,6 +13,8 @@ LL |         ay = z;
 error[E0597]: `y` does not live long enough
   --> $DIR/regions-nested-fns.rs:5:18
    |
+LL |     let y = 3;
+   |         - binding `y` declared here
 LL |     let mut ay = &y;
    |                  ^^ borrowed value does not live long enough
 ...
diff --git a/tests/ui/regions/regions-pattern-typing-issue-19552.stderr b/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
index f77d94a24..18aec29ad 100644
--- a/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
+++ b/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
@@ -1,6 +1,8 @@
 error[E0597]: `line` does not live long enough
   --> $DIR/regions-pattern-typing-issue-19552.rs:5:14
    |
+LL |     let line = String::new();
+   |         ---- binding `line` declared here
 LL |     match [&*line] {
    |              ^^^^ borrowed value does not live long enough
 LL |         [ word ] => { assert_static(word); }
diff --git a/tests/ui/regions/regions-pattern-typing-issue-19997.stderr b/tests/ui/regions/regions-pattern-typing-issue-19997.stderr
index ae60e3c0d..0abe77a86 100644
--- a/tests/ui/regions/regions-pattern-typing-issue-19997.stderr
+++ b/tests/ui/regions/regions-pattern-typing-issue-19997.stderr
@@ -2,10 +2,10 @@ error[E0506]: cannot assign to `a1` because it is borrowed
   --> $DIR/regions-pattern-typing-issue-19997.rs:7:13
    |
 LL |     match (&a1,) {
-   |            --- borrow of `a1` occurs here
+   |            --- `a1` is borrowed here
 LL |         (&ref b0,) => {
 LL |             a1 = &f;
-   |             ^^^^^^^ assignment to borrowed `a1` occurs here
+   |             ^^^^^^^ `a1` is assigned to here but it was already borrowed
 LL |             drop(b0);
    |                  -- borrow later used here
 
diff --git a/tests/ui/regions/regions-static-bound-rpass.rs b/tests/ui/regions/regions-static-bound-rpass.rs
index 25232b455..e2ebb394d 100644
--- a/tests/ui/regions/regions-static-bound-rpass.rs
+++ b/tests/ui/regions/regions-static-bound-rpass.rs
@@ -1,5 +1,7 @@
 // run-pass
 
+#![warn(unused_lifetimes)]
+
 fn invariant_id<'a,'b>(t: &'b mut &'static ()) -> &'b mut &'a ()
     where 'a: 'static { t }
 //~^ WARN unnecessary lifetime parameter `'a`
diff --git a/tests/ui/regions/regions-static-bound-rpass.stderr b/tests/ui/regions/regions-static-bound-rpass.stderr
index 9355a409d..f0f3a4c52 100644
--- a/tests/ui/regions/regions-static-bound-rpass.stderr
+++ b/tests/ui/regions/regions-static-bound-rpass.stderr
@@ -1,13 +1,18 @@
 warning: unnecessary lifetime parameter `'a`
-  --> $DIR/regions-static-bound-rpass.rs:4:11
+  --> $DIR/regions-static-bound-rpass.rs:6:11
    |
 LL |     where 'a: 'static { t }
    |           ^^
    |
    = help: you can use the `'static` lifetime directly, in place of `'a`
+note: the lint level is defined here
+  --> $DIR/regions-static-bound-rpass.rs:3:9
+   |
+LL | #![warn(unused_lifetimes)]
+   |         ^^^^^^^^^^^^^^^^
 
 warning: unnecessary lifetime parameter `'a`
-  --> $DIR/regions-static-bound-rpass.rs:8:11
+  --> $DIR/regions-static-bound-rpass.rs:10:11
    |
 LL |     where 'a: 'static { t }
    |           ^^
@@ -15,7 +20,7 @@ LL |     where 'a: 'static { t }
    = help: you can use the `'static` lifetime directly, in place of `'a`
 
 warning: unnecessary lifetime parameter `'b`
-  --> $DIR/regions-static-bound-rpass.rs:12:19
+  --> $DIR/regions-static-bound-rpass.rs:14:19
    |
 LL |     where 'a: 'b, 'b: 'static { t }
    |                   ^^
diff --git a/tests/ui/regions/regions-static-bound.rs b/tests/ui/regions/regions-static-bound.rs
index 4d2455470..e7aa8795f 100644
--- a/tests/ui/regions/regions-static-bound.rs
+++ b/tests/ui/regions/regions-static-bound.rs
@@ -1,6 +1,8 @@
-fn static_id<'a,'b>(t: &'a ()) -> &'static ()
-    where 'a: 'static { t }
-//~^ WARN unnecessary lifetime parameter `'a`
+#![warn(unused_lifetimes)]
+
+fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t }
+//~^ WARN lifetime parameter `'b` never used
+//~| WARN unnecessary lifetime parameter `'a`
 
 fn static_id_indirect<'a,'b>(t: &'a ()) -> &'static ()
     where 'a: 'b, 'b: 'static { t }
diff --git a/tests/ui/regions/regions-static-bound.stderr b/tests/ui/regions/regions-static-bound.stderr
index 2886ec3ea..b314e9fe8 100644
--- a/tests/ui/regions/regions-static-bound.stderr
+++ b/tests/ui/regions/regions-static-bound.stderr
@@ -1,13 +1,27 @@
+warning: lifetime parameter `'b` never used
+  --> $DIR/regions-static-bound.rs:3:17
+   |
+LL | fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t }
+   |                -^^
+   |                |
+   |                help: elide the unused lifetime
+   |
+note: the lint level is defined here
+  --> $DIR/regions-static-bound.rs:1:9
+   |
+LL | #![warn(unused_lifetimes)]
+   |         ^^^^^^^^^^^^^^^^
+
 warning: unnecessary lifetime parameter `'a`
-  --> $DIR/regions-static-bound.rs:2:11
+  --> $DIR/regions-static-bound.rs:3:53
    |
-LL |     where 'a: 'static { t }
-   |           ^^
+LL | fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t }
+   |                                                     ^^
    |
    = help: you can use the `'static` lifetime directly, in place of `'a`
 
 warning: unnecessary lifetime parameter `'b`
-  --> $DIR/regions-static-bound.rs:6:19
+  --> $DIR/regions-static-bound.rs:8:19
    |
 LL |     where 'a: 'b, 'b: 'static { t }
    |                   ^^
@@ -15,7 +29,7 @@ LL |     where 'a: 'b, 'b: 'static { t }
    = help: you can use the `'static` lifetime directly, in place of `'b`
 
 error: lifetime may not live long enough
-  --> $DIR/regions-static-bound.rs:10:5
+  --> $DIR/regions-static-bound.rs:12:5
    |
 LL | fn static_id_wrong_way<'a>(t: &'a ()) -> &'static () where 'static: 'a {
    |                        -- lifetime `'a` defined here
@@ -23,7 +37,7 @@ LL |     t
    |     ^ returning this value requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
-  --> $DIR/regions-static-bound.rs:15:5
+  --> $DIR/regions-static-bound.rs:17:5
    |
 LL | fn error(u: &(), v: &()) {
    |          -  - let's call the lifetime of this reference `'1`
@@ -36,7 +50,7 @@ LL |     static_id(&u);
    |     argument requires that `'1` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of function
-  --> $DIR/regions-static-bound.rs:17:5
+  --> $DIR/regions-static-bound.rs:19:5
    |
 LL | fn error(u: &(), v: &()) {
    |                  -  - let's call the lifetime of this reference `'2`
@@ -49,6 +63,6 @@ LL |     static_id_indirect(&v);
    |     `v` escapes the function body here
    |     argument requires that `'2` must outlive `'static`
 
-error: aborting due to 3 previous errors; 2 warnings emitted
+error: aborting due to 3 previous errors; 3 warnings emitted
 
 For more information about this error, try `rustc --explain E0521`.
diff --git a/tests/ui/regions/resolve-re-error-ice.rs b/tests/ui/regions/resolve-re-error-ice.rs
new file mode 100644
index 000000000..f37b27a82
--- /dev/null
+++ b/tests/ui/regions/resolve-re-error-ice.rs
@@ -0,0 +1,22 @@
+// check-pass
+
+// Allow this for now, can remove this UI test when this becomes a hard error.
+#![allow(implied_bounds_entailment)]
+
+use std::collections::hash_map::{Keys, HashMap};
+use std::marker::PhantomData;
+
+trait MapAssertion<'a, K, V, R> {
+    fn key_set(&self) -> Subject<Keys<K, V>, (), R>;
+}
+
+struct Subject<'a, T, V, R>(PhantomData<(&'a T, V, R)>);
+
+impl<'a, K, V, R> MapAssertion<'a, K, V, R> for Subject<'a, HashMap<K, V>, (), R>
+{
+    fn key_set(&self) -> Subject<'a, Keys<K, V>, (), R> {
+        todo!()
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/regions/resolve-re-error-ice.stderr b/tests/ui/regions/resolve-re-error-ice.stderr
new file mode 100644
index 000000000..e7003e1c3
--- /dev/null
+++ b/tests/ui/regions/resolve-re-error-ice.stderr
@@ -0,0 +1,15 @@
+Future incompatibility report: Future breakage diagnostic:
+warning: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/resolve-re-error-ice.rs:17:16
+   |
+LL |     fn key_set(&self) -> Subject<'a, Keys<K, V>, (), R> {
+   |                ^^^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this type to make the impl signature compatible: `Subject<'_, std::collections::hash_map::Keys<'_, K, V>, (), R>`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #105572 <https://github.com/rust-lang/rust/issues/105572>
+note: the lint level is defined here
+  --> $DIR/resolve-re-error-ice.rs:4:10
+   |
+LL | #![allow(implied_bounds_entailment)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
+