update diagnostics

lcnr · lcnr · commit 374b121c65aa · 2025-02-12T10:14:47.000+01:00
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -61,7 +61,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         let tcx = self.tcx;
         let mut span = obligation.cause.span;
         let mut long_ty_file = None;
-
         let mut err = match *error {
             SelectionError::Unimplemented => {
                 // If this obligation was generated as a result of well-formedness checking, see if we
@@ -585,6 +584,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(ty)) => {
                         let ty = self.resolve_vars_if_possible(ty);
                         if self.next_trait_solver() {
+                            if let Err(guar) = ty.error_reported() {
+                                return guar;
+                            }
+
                             // FIXME: we'll need a better message which takes into account
                             // which bounds actually failed to hold.
                             self.dcx().struct_span_err(
@@ -1201,6 +1204,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
+    #[instrument(level = "trace", skip(self), ret)]
     fn can_match_trait(
         &self,
         goal: ty::TraitPredicate<'tcx>,
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
@@ -172,8 +172,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             {
                 1
             }
-            ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3,
             ty::PredicateKind::Coerce(_) => 2,
+            ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3,
             _ => 0,
         });
 
diff --git a/compiler/rustc_trait_selection/src/infer.rs b/compiler/rustc_trait_selection/src/infer.rs
@@ -19,6 +19,7 @@ use crate::traits::{self, Obligation, ObligationCause, ObligationCtxt, Selection
 
 #[extension(pub trait InferCtxtExt<'tcx>)]
 impl<'tcx> InferCtxt<'tcx> {
+    #[instrument(level = "trace", skip(self), ret)]
     fn can_eq<T: ToTrace<'tcx>>(&self, param_env: ty::ParamEnv<'tcx>, a: T, b: T) -> bool {
         self.probe(|_| {
             let ocx = ObligationCtxt::new(self);
diff --git a/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs b/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs
@@ -139,6 +139,7 @@ pub(super) fn fulfillment_error_for_overflow<'tcx>(
     }
 }
 
+#[instrument(level = "debug", skip(infcx), ret)]
 fn find_best_leaf_obligation<'tcx>(
     infcx: &InferCtxt<'tcx>,
     obligation: &PredicateObligation<'tcx>,
@@ -211,11 +212,7 @@ impl<'tcx> BestObligation<'tcx> {
                                             | GoalSource::AliasBoundConstCondition
                                             | GoalSource::InstantiateHigherRanked
                                             | GoalSource::AliasWellFormed
-                                    ) && match (self.consider_ambiguities, nested_goal.result()) {
-                                        (true, Ok(Certainty::Maybe(MaybeCause::Ambiguity)))
-                                        | (false, Err(_)) => true,
-                                        _ => false,
-                                    }
+                                    ) && nested_goal.result().is_err()
                                 },
                             )
                         })
@@ -277,11 +274,37 @@ impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> {
 
     #[instrument(level = "trace", skip(self, goal), fields(goal = ?goal.goal()))]
     fn visit_goal(&mut self, goal: &inspect::InspectGoal<'_, 'tcx>) -> Self::Result {
+        let tcx = goal.infcx().tcx;
+        let pred_kind = goal.goal().predicate.kind();
+
         let candidates = self.non_trivial_candidates(goal);
-        trace!(candidates = ?candidates.iter().map(|c| c.kind()).collect::<Vec<_>>());
+        let candidate = match candidates.as_slice() {
+            [] => {
+                // Similar to `AliasRelate` goals, `NormalizesTo` may fail because the
+                // used alias is not well-formed. We only enter an actual `RigidAlias`
+                // candidate if its trait bound was proven via the environment. We therefore
+                // manually check whether the alias is even well-formed here.
+                if let Some(ty::PredicateKind::NormalizesTo(pred)) = pred_kind.no_bound_vars() {
+                    if let Some(obligation) = goal
+                        .infcx()
+                        .visit_proof_tree_at_depth(
+                            goal.goal().with(
+                                goal.infcx().tcx,
+                                ty::ClauseKind::WellFormed(pred.alias.to_term(tcx).into()),
+                            ),
+                            goal.depth() + 1,
+                            self,
+                        )
+                        .break_value()
+                    {
+                        return ControlFlow::Break(obligation);
+                    }
+                }
 
-        let [candidate] = candidates.as_slice() else {
-            return ControlFlow::Break(self.obligation.clone());
+                return ControlFlow::Break(self.obligation.clone());
+            }
+            [candidate] => candidate,
+            _ => return ControlFlow::Break(self.obligation.clone()),
         };
 
         // Don't walk into impls that have `do_not_recommend`.
@@ -291,13 +314,12 @@ impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> {
         } = candidate.kind()
             && goal.infcx().tcx.do_not_recommend_impl(impl_def_id)
         {
+            trace!("#[do_not_recommend] -> exit");
             return ControlFlow::Break(self.obligation.clone());
         }
 
-        let tcx = goal.infcx().tcx;
         // FIXME: Also, what about considering >1 layer up the stack? May be necessary
         // for normalizes-to.
-        let pred_kind = goal.goal().predicate.kind();
         let child_mode = match pred_kind.skip_binder() {
             ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => {
                 ChildMode::Trait(pred_kind.rebind(pred))
diff --git a/tests/ui/associated-types/defaults-unsound-62211-1.next.stderr b/tests/ui/associated-types/defaults-unsound-62211-1.next.stderr
@@ -37,11 +37,6 @@ error[E0277]: the trait bound `Self: Deref` is not satisfied
 LL |     type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;
    |                                                                                                ^^^^ the trait `Deref` is not implemented for `Self`
    |
-note: required by a bound in `UncheckedCopy::Output`
-  --> $DIR/defaults-unsound-62211-1.rs:24:31
-   |
-LL |     type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;
-   |                               ^^^^^^^^^^^^ required by this bound in `UncheckedCopy::Output`
 help: consider further restricting `Self`
    |
 LL | trait UncheckedCopy: Sized + Deref {
diff --git a/tests/ui/associated-types/defaults-unsound-62211-2.next.stderr b/tests/ui/associated-types/defaults-unsound-62211-2.next.stderr
@@ -37,11 +37,6 @@ error[E0277]: the trait bound `Self: Deref` is not satisfied
 LL |     type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;
    |                                                                                                ^^^^ the trait `Deref` is not implemented for `Self`
    |
-note: required by a bound in `UncheckedCopy::Output`
-  --> $DIR/defaults-unsound-62211-2.rs:24:31
-   |
-LL |     type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;
-   |                               ^^^^^^^^^^^^ required by this bound in `UncheckedCopy::Output`
 help: consider further restricting `Self`
    |
 LL | trait UncheckedCopy: Sized + Deref {
diff --git a/tests/ui/associated-types/issue-54108.next.stderr b/tests/ui/associated-types/issue-54108.next.stderr
@@ -5,11 +5,6 @@ LL |     type Size = <Self as SubEncoder>::ActualSize;
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `<T as SubEncoder>::ActualSize + <T as SubEncoder>::ActualSize`
    |
    = help: the trait `Add` is not implemented for `<T as SubEncoder>::ActualSize`
-note: required by a bound in `Encoder::Size`
-  --> $DIR/issue-54108.rs:8:20
-   |
-LL |     type Size: Add<Output = Self::Size>;
-   |                    ^^^^^^^^^^^^^^^^^^^ required by this bound in `Encoder::Size`
 help: consider further restricting the associated type
    |
 LL -     T: SubEncoder,
diff --git a/tests/ui/auto-traits/assoc-ty.next.stderr b/tests/ui/auto-traits/assoc-ty.next.stderr
@@ -21,20 +21,21 @@ LL | | }
    = help: add `#![feature(auto_traits)]` 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[E0308]: mismatched types
-  --> $DIR/assoc-ty.rs:15:36
+error[E0271]: type mismatch resolving `<() as Trait>::Output normalizes-to _`
+  --> $DIR/assoc-ty.rs:15:12
    |
 LL |     let _: <() as Trait>::Output = ();
-   |            ---------------------   ^^ types differ
-   |            |
-   |            expected due to this
+   |            ^^^^^^^^^^^^^^^^^^^^^ types differ
+
+error[E0271]: type mismatch resolving `<() as Trait>::Output normalizes-to _`
+  --> $DIR/assoc-ty.rs:15:12
+   |
+LL |     let _: <() as Trait>::Output = ();
+   |            ^^^^^^^^^^^^^^^^^^^^^ types differ
    |
-   = note: expected associated type `<() as Trait>::Output`
-                    found unit type `()`
-   = help: consider constraining the associated type `<() as Trait>::Output` to `()` or calling a method that returns `<() as Trait>::Output`
-   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0308, E0380, E0658.
-For more information about an error, try `rustc --explain E0308`.
+Some errors have detailed explanations: E0271, E0380, E0658.
+For more information about an error, try `rustc --explain E0271`.
diff --git a/tests/ui/auto-traits/assoc-ty.rs b/tests/ui/auto-traits/assoc-ty.rs
@@ -13,5 +13,7 @@ auto trait Trait {
 
 fn main() {
     let _: <() as Trait>::Output = ();
-    //~^ ERROR mismatched types
+    //[current]~^ ERROR mismatched types
+    //[next]~^^ ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _`
+    //[next]~| ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _`
 }
diff --git a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr
@@ -23,7 +23,19 @@ error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()`
 LL |     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {}
    |                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ
 
-error: aborting due to 3 previous errors
+error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _`
+  --> $DIR/ice-unexpected-param-type-whensubstituting-in-region-112823.rs:28:73
+   |
+LL |     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {}
+   |                                                                         ^^ types differ
+
+error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _`
+  --> $DIR/ice-unexpected-param-type-whensubstituting-in-region-112823.rs:28:5
+   |
+LL |     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ
+
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0049, E0271, E0407.
 For more information about an error, try `rustc --explain E0049`.
diff --git a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs
@@ -26,9 +26,11 @@ impl X for Y {
     //~^ ERROR type `LineStream` has 0 type parameters but its trait declaration has 1 type parameter
     type LineStreamFut<'a, Repr> = impl Future<Output = Self::LineStream<'a, Repr>>;
     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {}
-    //[current]~^ ERROR `()` is not a future
-    //[next]~^^ ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()`
-    //~^^^ method `line_stream` is not a member of trait `X`
+    //~^ method `line_stream` is not a member of trait `X`
+    //[current]~^^ ERROR `()` is not a future
+    //[next]~^^^ ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()`
+    //[next]~| ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _`
+    //[next]~| ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _`
 }
 
 pub fn main() {}
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.current.fixed b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.current.fixed
@@ -6,8 +6,10 @@ fn main() {
     let _ = (-10..=10).find(|x: &i32| x.signum() == 0);
     //[current]~^ ERROR type mismatch in closure arguments
     //[next]~^^ ERROR expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found
+    //[next]~| ERROR expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
     let _ = (-10..=10).find(|x: &i32| x.signum() == 0);
     //[current]~^ ERROR type mismatch in closure arguments
     //[next]~^^ ERROR expected `RangeInclusive<{integer}>` to be an iterator that yields `&&i32`, but it yields `{integer}`
     //[next]~| ERROR expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found
+    //[next]~| ERROR expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
 }
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.current.stderr b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.current.stderr
@@ -16,7 +16,7 @@ LL |     let _ = (-10..=10).find(|x: &i32| x.signum() == 0);
    |                                 +
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:9:24
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:10:24
    |
 LL |     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
    |                        ^^^^ ----------- found signature defined here
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.next.stderr b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.next.stderr
@@ -12,27 +12,47 @@ LL |     let _ = (-10..=10).find(|x: i32| x.signum() == 0);
 note: required by a bound in `find`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
+error[E0277]: expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:6:24
+   |
+LL |     let _ = (-10..=10).find(|x: i32| x.signum() == 0);
+   |                        ^^^^ expected an `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
+   |
+   = help: the trait `for<'a> FnOnce(&'a {integer})` is not implemented for closure `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
+   = note: expected a closure with arguments `(i32,)`
+              found a closure with arguments `(&{integer},)`
+
 error[E0271]: expected `RangeInclusive<{integer}>` to be an iterator that yields `&&i32`, but it yields `{integer}`
-  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:9:24
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:10:24
    |
 LL |     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
    |                        ^^^^ expected `&&i32`, found integer
 
-error[E0277]: expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:9:29: 9:40}`
-  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:9:29
+error[E0277]: expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:10:29
    |
 LL |     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
-   |                        ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:9:29: 9:40}`
+   |                        ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
    |                        |
    |                        required by a bound introduced by this call
    |
-   = help: the trait `for<'a> FnMut(&'a <std::ops::RangeInclusive<{integer}> as Iterator>::Item)` is not implemented for closure `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:9:29: 9:40}`
+   = help: the trait `for<'a> FnMut(&'a <std::ops::RangeInclusive<{integer}> as Iterator>::Item)` is not implemented for closure `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
    = note: expected a closure with arguments `(&&&i32,)`
               found a closure with arguments `(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item,)`
 note: required by a bound in `find`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error: aborting due to 3 previous errors
+error[E0277]: expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:10:24
+   |
+LL |     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
+   |                        ^^^^ expected an `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
+   |
+   = help: the trait `for<'a> FnOnce(&'a {integer})` is not implemented for closure `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
+   = note: expected a closure with arguments `(&&&i32,)`
+              found a closure with arguments `(&{integer},)`
+
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0271, E0277.
 For more information about an error, try `rustc --explain E0271`.
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs
@@ -6,8 +6,10 @@ fn main() {
     let _ = (-10..=10).find(|x: i32| x.signum() == 0);
     //[current]~^ ERROR type mismatch in closure arguments
     //[next]~^^ ERROR expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found
+    //[next]~| ERROR expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
     //[current]~^ ERROR type mismatch in closure arguments
     //[next]~^^ ERROR expected `RangeInclusive<{integer}>` to be an iterator that yields `&&i32`, but it yields `{integer}`
     //[next]~| ERROR expected a `FnMut(&<std::ops::RangeInclusive<{integer}> as Iterator>::Item)` closure, found
+    //[next]~| ERROR expected a `FnOnce(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
 }
diff --git a/tests/ui/traits/next-solver/fn-trait.rs b/tests/ui/traits/next-solver/fn-trait.rs
@@ -19,10 +19,14 @@ fn main() {
     require_fn(f as fn() -> i32);
     require_fn(f as unsafe fn() -> i32);
     //~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32`
+    //~| ERROR: expected a `FnOnce()` closure, found `unsafe fn() -> i32`
     require_fn(g);
     //~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32 {g}`
+    //~| ERROR: expected a `FnOnce()` closure, found `extern "C" fn() -> i32 {g}`
     require_fn(g as extern "C" fn() -> i32);
     //~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32`
+    //~| ERROR: expected a `FnOnce()` closure, found `extern "C" fn() -> i32`
     require_fn(h);
     //~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32 {h}`
+    //~| ERROR: expected a `FnOnce()` closure, found `unsafe fn() -> i32 {h}`
 }
diff --git a/tests/ui/traits/next-solver/fn-trait.stderr b/tests/ui/traits/next-solver/fn-trait.stderr

Original file line number	Diff line number	Diff line change
`@@ -172,8 +172,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {`
`172`	`172`	`{`
`173`	`173`	`1`
`174`	`174`	`}`
`175`		`- ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3,`
`176`	`175`	`ty::PredicateKind::Coerce(_) => 2,`
	`176`	`+ ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3,`
`177`	`177`	`_ => 0,`
`178`	`178`	`});`
`179`	`179`
Original file line number	Diff line number	Diff line change
@@ -37,11 +37,6 @@ error[E0277]: the trait bound `Self: Deref` is not satisfied
`37`	`37`	`LL \| type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;`
`38`	`38`	\| ^^^^ the trait `Deref` is not implemented for `Self`
`39`	`39`	`\|`
`40`		-note: required by a bound in `UncheckedCopy::Output`
`41`		`- --> $DIR/defaults-unsound-62211-1.rs:24:31`
`42`		`- \|`
`43`		`-LL \| type Output: Copy + Deref<Target = str> + AddAssign<&'static str> + From<Self> + Display = Self;`
`44`		- \| ^^^^^^^^^^^^ required by this bound in `UncheckedCopy::Output`
`45`	`40`	help: consider further restricting `Self`
`46`	`41`	`\|`
`47`	`42`	`LL \| trait UncheckedCopy: Sized + Deref {`
Original file line number	Diff line number	Diff line change
`@@ -5,11 +5,6 @@ LL \| type Size = <Self as SubEncoder>::ActualSize;`
`5`	`5`	\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `<T as SubEncoder>::ActualSize + <T as SubEncoder>::ActualSize`
`6`	`6`	`\|`
`7`	`7`	= help: the trait `Add` is not implemented for `<T as SubEncoder>::ActualSize`
`8`		-note: required by a bound in `Encoder::Size`
`9`		`- --> $DIR/issue-54108.rs:8:20`
`10`		`- \|`
`11`		`-LL \| type Size: Add<Output = Self::Size>;`
`12`		- \| ^^^^^^^^^^^^^^^^^^^ required by this bound in `Encoder::Size`
`13`	`8`	`help: consider further restricting the associated type`
`14`	`9`	`\|`
`15`	`10`	`LL - T: SubEncoder,`
Original file line number	Diff line number	Diff line change
`@@ -13,5 +13,7 @@ auto trait Trait {`
`13`	`13`
`14`	`14`	`fn main() {`
`15`	`15`	`let _: <() as Trait>::Output = ();`
`16`		`- //~^ ERROR mismatched types`
	`16`	`+ //[current]~^ ERROR mismatched types`
	`17`	+ //[next]~^^ ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _`
	`18`	+ //[next]~\| ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _`
`17`	`19`	`}`