Auto merge of rust-lang#113429 - compiler-errors:rollup-wkv4w9a, r=compiler-errors

Rollup of 8 pull requests

Successful merges:

 - rust-lang#111917 (Simplify duplicate checks for mir validator)
 - rust-lang#112008 (Fix incorrect documented default bufsize in bufreader/writer)
 - rust-lang#112825 (Don't call `type_of` on TAIT in defining scope in new solver)
 - rust-lang#113164 (Add a regression test for rust-lang#109054)
 - rust-lang#113318 (Revert "alloc: Allow comparing Boxs over different allocators", add regression test)
 - rust-lang#113397 (Prefer object candidates in new selection)
 - rust-lang#113419 (Avoid calling item_name for RPITIT)
 - rust-lang#113421 (Do not assert >1 RPITITs on collect_return_position_impl_trait_in_trait_tys)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_const_eval/src/transform/validate.rs

@@ -67,8 +67,8 @@ impl<'tcx> MirPass<'tcx> for Validator {
             unwind_edge_count: 0,
             reachable_blocks: traversal::reachable_as_bitset(body),
             storage_liveness,
-            place_cache: Vec::new(),
-            value_cache: Vec::new(),
+            place_cache: FxHashSet::default(),
+            value_cache: FxHashSet::default(),
         };
         checker.visit_body(body);
         checker.check_cleanup_control_flow();
@@ -95,8 +95,8 @@ struct TypeChecker<'a, 'tcx> {
     unwind_edge_count: usize,
     reachable_blocks: BitSet<BasicBlock>,
     storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>,
-    place_cache: Vec<PlaceRef<'tcx>>,
-    value_cache: Vec<u128>,
+    place_cache: FxHashSet<PlaceRef<'tcx>>,
+    value_cache: FxHashSet<u128>,
 }
 
 impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
@@ -951,10 +951,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
 
                 self.value_cache.clear();
                 self.value_cache.extend(targets.iter().map(|(value, _)| value));
-                let all_len = self.value_cache.len();
-                self.value_cache.sort_unstable();
-                self.value_cache.dedup();
-                let has_duplicates = all_len != self.value_cache.len();
+                let has_duplicates = targets.iter().len() != self.value_cache.len();
                 if has_duplicates {
                     self.fail(
                         location,
@@ -987,16 +984,14 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                 // passed by a reference to the callee. Consequently they must be non-overlapping.
                 // Currently this simply checks for duplicate places.
                 self.place_cache.clear();
-                self.place_cache.push(destination.as_ref());
+                self.place_cache.insert(destination.as_ref());
+                let mut has_duplicates = false;
                 for arg in args {
                     if let Operand::Move(place) = arg {
-                        self.place_cache.push(place.as_ref());
+                        has_duplicates |= !self.place_cache.insert(place.as_ref());
                     }
                 }
-                let all_len = self.place_cache.len();
-                let mut dedup = FxHashSet::default();
-                self.place_cache.retain(|p| dedup.insert(*p));
-                let has_duplicates = all_len != self.place_cache.len();
+
                 if has_duplicates {
                     self.fail(
                         location,

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -669,11 +669,13 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
         )
         .fold_with(&mut collector);
 
-    debug_assert_ne!(
-        collector.types.len(),
-        0,
-        "expect >1 RPITITs in call to `collect_return_position_impl_trait_in_trait_tys`"
-    );
+    if !unnormalized_trait_sig.output().references_error() {
+        debug_assert_ne!(
+            collector.types.len(),
+            0,
+            "expect >1 RPITITs in call to `collect_return_position_impl_trait_in_trait_tys`"
+        );
+    }
 
     let trait_sig = ocx.normalize(&norm_cause, param_env, unnormalized_trait_sig);
     trait_sig.error_reported()?;

compiler/rustc_infer/src/traits/error_reporting/mod.rs

@@ -25,9 +25,11 @@ impl<'tcx> InferCtxt<'tcx> {
             "impl has stricter requirements than trait"
         );
 
-        if let Some(span) = self.tcx.hir().span_if_local(trait_item_def_id) {
-            let item_name = self.tcx.item_name(impl_item_def_id.to_def_id());
-            err.span_label(span, format!("definition of `{}` from trait", item_name));
+        if !self.tcx.is_impl_trait_in_trait(trait_item_def_id) {
+            if let Some(span) = self.tcx.hir().span_if_local(trait_item_def_id) {
+                let item_name = self.tcx.item_name(impl_item_def_id.to_def_id());
+                err.span_label(span, format!("definition of `{}` from trait", item_name));
+            }
         }
 
         err.span_label(error_span, format!("impl has extra requirement {}", requirement));

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -837,7 +837,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    pub(super) fn can_define_opaque_ty(&mut self, def_id: LocalDefId) -> bool {
+    pub(super) fn can_define_opaque_ty(&self, def_id: LocalDefId) -> bool {
         self.infcx.opaque_type_origin(def_id).is_some()
     }
 

compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs

@@ -173,10 +173,18 @@ fn candidate_should_be_dropped_in_favor_of<'tcx>(
             victim_idx >= other_idx
         }
         (_, CandidateSource::ParamEnv(_)) => true,
+
+        (
+            CandidateSource::BuiltinImpl(BuiltinImplSource::Object),
+            CandidateSource::BuiltinImpl(BuiltinImplSource::Object),
+        ) => false,
+        (_, CandidateSource::BuiltinImpl(BuiltinImplSource::Object)) => true,
+
         (CandidateSource::Impl(victim_def_id), CandidateSource::Impl(other_def_id)) => {
             tcx.specializes((other_def_id, victim_def_id))
                 && other.result.value.certainty == Certainty::Yes
         }
+
         _ => false,
     }
 }

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -7,6 +7,7 @@ use rustc_hir::{LangItem, Movability};
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::util::supertraits;
 use rustc_middle::traits::solve::{CanonicalResponse, Certainty, Goal, QueryResult};
+use rustc_middle::traits::Reveal;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams, TreatProjections};
 use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
 use rustc_middle::ty::{TraitPredicate, TypeVisitableExt};
@@ -118,6 +119,32 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
             return result;
         }
 
+        // Don't call `type_of` on a local TAIT that's in the defining scope,
+        // since that may require calling `typeck` on the same item we're
+        // currently type checking, which will result in a fatal cycle that
+        // ideally we want to avoid, since we can make progress on this goal
+        // via an alias bound or a locally-inferred hidden type instead.
+        //
+        // Also, don't call `type_of` on a TAIT in `Reveal::All` mode, since
+        // we already normalize the self type in
+        // `assemble_candidates_after_normalizing_self_ty`, and we'd
+        // just be registering an identical candidate here.
+        //
+        // Returning `Err(NoSolution)` here is ok in `SolverMode::Coherence`
+        // since we'll always be registering an ambiguous candidate in
+        // `assemble_candidates_after_normalizing_self_ty` due to normalizing
+        // the TAIT.
+        if let ty::Alias(ty::Opaque, opaque_ty) = goal.predicate.self_ty().kind() {
+            if matches!(goal.param_env.reveal(), Reveal::All)
+                || opaque_ty
+                    .def_id
+                    .as_local()
+                    .is_some_and(|def_id| ecx.can_define_opaque_ty(def_id))
+            {
+                return Err(NoSolution);
+            }
+        }
+
         ecx.probe_and_evaluate_goal_for_constituent_tys(
             goal,
             structural_traits::instantiate_constituent_tys_for_auto_trait,

library/alloc/src/boxed.rs

@@ -1319,56 +1319,39 @@ impl Clone for Box<str> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A1, A2> PartialEq<Box<T, A2>> for Box<T, A1>
-where
-    T: ?Sized + PartialEq,
-    A1: Allocator,
-    A2: Allocator,
-{
+impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for Box<T, A> {
     #[inline]
-    fn eq(&self, other: &Box<T, A2>) -> bool {
+    fn eq(&self, other: &Self) -> bool {
         PartialEq::eq(&**self, &**other)
     }
-
     #[inline]
-    fn ne(&self, other: &Box<T, A2>) -> bool {
+    fn ne(&self, other: &Self) -> bool {
         PartialEq::ne(&**self, &**other)
     }
 }
-
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A1, A2> PartialOrd<Box<T, A2>> for Box<T, A1>
-where
-    T: ?Sized + PartialOrd,
-    A1: Allocator,
-    A2: Allocator,
-{
+impl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd for Box<T, A> {
     #[inline]
-    fn partial_cmp(&self, other: &Box<T, A2>) -> Option<Ordering> {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         PartialOrd::partial_cmp(&**self, &**other)
     }
-
     #[inline]
-    fn lt(&self, other: &Box<T, A2>) -> bool {
+    fn lt(&self, other: &Self) -> bool {
         PartialOrd::lt(&**self, &**other)
     }
-
     #[inline]
-    fn le(&self, other: &Box<T, A2>) -> bool {
+    fn le(&self, other: &Self) -> bool {
         PartialOrd::le(&**self, &**other)
     }
-
     #[inline]
-    fn ge(&self, other: &Box<T, A2>) -> bool {
+    fn ge(&self, other: &Self) -> bool {
         PartialOrd::ge(&**self, &**other)
     }
-
     #[inline]
-    fn gt(&self, other: &Box<T, A2>) -> bool {
+    fn gt(&self, other: &Self) -> bool {
         PartialOrd::gt(&**self, &**other)
     }
 }
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + Ord, A: Allocator> Ord for Box<T, A> {
     #[inline]

library/std/src/io/buffered/bufreader.rs

@@ -53,7 +53,7 @@ pub struct BufReader<R: ?Sized> {
 }
 
 impl<R: Read> BufReader<R> {
-    /// Creates a new `BufReader<R>` with a default buffer capacity. The default is currently 8 KB,
+    /// Creates a new `BufReader<R>` with a default buffer capacity. The default is currently 8 KiB,
     /// but may change in the future.
     ///
     /// # Examples

library/std/src/io/buffered/bufwriter.rs

@@ -81,7 +81,7 @@ pub struct BufWriter<W: ?Sized + Write> {
 }
 
 impl<W: Write> BufWriter<W> {
-    /// Creates a new `BufWriter<W>` with a default buffer capacity. The default is currently 8 KB,
+    /// Creates a new `BufWriter<W>` with a default buffer capacity. The default is currently 8 KiB,
     /// but may change in the future.
     ///
     /// # Examples

tests/ui/async-await/in-trait/return-not-existing-pair.current.stderr

@@ -0,0 +1,39 @@
+error[E0726]: implicit elided lifetime not allowed here
+  --> $DIR/return-not-existing-pair.rs:12:20
+   |
+LL | impl<'a, 'b, T, U> MyTrait<T> for U {
+   |                    ^^^^^^^^^^ expected lifetime parameters
+   |
+help: indicate the anonymous lifetimes
+   |
+LL | impl<'a, 'b, T, U> MyTrait<'_, '_, T> for U {
+   |                            +++++++
+
+error[E0412]: cannot find type `ConnImpl` in this scope
+  --> $DIR/return-not-existing-pair.rs:8:48
+   |
+LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
+   |                                                ^^^^^^^^ not found in this scope
+
+error[E0186]: method `foo` has a `&self` declaration in the trait, but not in the impl
+  --> $DIR/return-not-existing-pair.rs:14:5
+   |
+LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
+   |     ------------------------------------------------------------ `&self` used in trait
+...
+LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl
+
+error[E0308]: mismatched types
+  --> $DIR/return-not-existing-pair.rs:14:42
+   |
+LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
+   |                                          ^^ expected `(&U, &T)`, found `()`
+   |
+   = note:  expected tuple `(&'a U, &'b T)`
+           found unit type `()`
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0186, E0308, E0412, E0726.
+For more information about an error, try `rustc --explain E0186`.

tests/ui/async-await/in-trait/return-not-existing-pair.next.stderr

@@ -0,0 +1,39 @@
+error[E0726]: implicit elided lifetime not allowed here
+  --> $DIR/return-not-existing-pair.rs:12:20
+   |
+LL | impl<'a, 'b, T, U> MyTrait<T> for U {
+   |                    ^^^^^^^^^^ expected lifetime parameters
+   |
+help: indicate the anonymous lifetimes
+   |
+LL | impl<'a, 'b, T, U> MyTrait<'_, '_, T> for U {
+   |                            +++++++
+
+error[E0412]: cannot find type `ConnImpl` in this scope
+  --> $DIR/return-not-existing-pair.rs:8:48
+   |
+LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
+   |                                                ^^^^^^^^ not found in this scope
+
+error[E0186]: method `foo` has a `&self` declaration in the trait, but not in the impl
+  --> $DIR/return-not-existing-pair.rs:14:5
+   |
+LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
+   |     ------------------------------------------------------------ `&self` used in trait
+...
+LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl
+
+error[E0308]: mismatched types
+  --> $DIR/return-not-existing-pair.rs:14:42
+   |
+LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
+   |                                          ^^ expected `(&U, &T)`, found `()`
+   |
+   = note:  expected tuple `(&'a U, &'b T)`
+           found unit type `()`
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0186, E0308, E0412, E0726.
+For more information about an error, try `rustc --explain E0186`.

tests/ui/async-await/in-trait/return-not-existing-pair.rs

@@ -0,0 +1,19 @@
+// edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
+#![feature(async_fn_in_trait)]
+
+trait MyTrait<'a, 'b, T> {
+    async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
+    //~^ ERROR: cannot find type `ConnImpl` in this scope [E0412]
+}
+
+impl<'a, 'b, T, U> MyTrait<T> for U {
+    //~^ ERROR: implicit elided lifetime not allowed here [E0726]
+    async fn foo(_: T) -> (&'a U, &'b T) {}
+    //~^ ERROR: method `foo` has a `&self` declaration in the trait, but not in the impl [E0186]
+    //~| ERROR: mismatched types [E0308]
+}
+
+fn main() {}

tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.current.stderr

@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+  --> $DIR/return-not-existing-type-wrapping-rpitit.rs:10:25
+   |
+LL |     fn bar() -> Wrapper<Missing<impl Sized>>;
+   |                         ^^^^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.

tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.next.stderr

@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+  --> $DIR/return-not-existing-type-wrapping-rpitit.rs:10:25
+   |
+LL |     fn bar() -> Wrapper<Missing<impl Sized>>;
+   |                         ^^^^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.

tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs

@@ -0,0 +1,20 @@
+// edition:2021
+// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
+// revisions: current next
+
+#![feature(return_position_impl_trait_in_trait)]
+
+struct Wrapper<T>(T);
+
+trait Foo {
+    fn bar() -> Wrapper<Missing<impl Sized>>;
+    //~^ ERROR: cannot find type `Missing` in this scope [E0412]
+}
+
+impl Foo for () {
+    fn bar() -> Wrapper<i32> {
+        Wrapper(0)
+    }
+}
+
+fn main() {}

tests/ui/traits/new-solver/dont-remap-tait-substs.rs

@@ -1,5 +1,5 @@
 // compile-flags: -Ztrait-solver=next
-// known-bug: #112825
+// check-pass
 
 // Makes sure we don't prepopulate the MIR typeck of `define`
 // with `Foo<T, U> = T`, but instead, `Foo<B, A> = B`, so that