Auto merge of rust-lang#133694 - matthiaskrgr:rollup-s6xj4rf, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#128184 (std: refactor `pthread`-based synchronization)
 - rust-lang#132047 (Robustify and genericize return-type-notation resolution in `resolve_bound_vars`)
 - rust-lang#133515 (fix: hurd build, stat64.st_fsid was renamed to st_dev)
 - rust-lang#133602 (fix: fix codeblocks in `PathBuf` example)
 - rust-lang#133622 (update link to "C++ Exceptions under the hood" blog)
 - rust-lang#133660 (Do not create trait object type if missing associated types)
 - rust-lang#133686 (Add diagnostic item for `std::ops::ControlFlow`)
 - rust-lang#133689 (Fixed typos by changing `happend` to `happened`)

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

Author: bors

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -2060,48 +2060,37 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                 };
                 match path.res {
                     Res::Def(DefKind::TyParam, _) | Res::SelfTyParam { trait_: _ } => {
-                        // Get the generics of this type's hir owner. This is *different*
-                        // from the generics of the parameter's definition, since we want
-                        // to be able to resolve an RTN path on a nested body (e.g. method
-                        // inside an impl) using the where clauses on the method.
-                        // FIXME(return_type_notation): Think of some better way of doing this.
-                        let Some(generics) = self.tcx.hir_owner_node(hir_id.owner).generics()
-                        else {
-                            return;
-                        };
-
-                        // Look for the first bound that contains an associated type that
-                        // matches the segment that we're looking for. We ignore any subsequent
-                        // bounds since we'll be emitting a hard error in HIR lowering, so this
-                        // is purely speculative.
-                        let one_bound = generics.predicates.iter().find_map(|predicate| {
-                            let hir::WherePredicateKind::BoundPredicate(predicate) = predicate.kind
-                            else {
-                                return None;
-                            };
-                            let hir::TyKind::Path(hir::QPath::Resolved(None, bounded_path)) =
-                                predicate.bounded_ty.kind
-                            else {
-                                return None;
-                            };
-                            if bounded_path.res != path.res {
-                                return None;
-                            }
-                            predicate.bounds.iter().find_map(|bound| {
-                                let hir::GenericBound::Trait(trait_) = bound else {
-                                    return None;
-                                };
+                        let mut bounds =
+                            self.for_each_trait_bound_on_res(path.res).filter_map(|trait_def_id| {
                                 BoundVarContext::supertrait_hrtb_vars(
                                     self.tcx,
-                                    trait_.trait_ref.trait_def_id()?,
+                                    trait_def_id,
                                     item_segment.ident,
                                     ty::AssocKind::Fn,
                                 )
-                            })
-                        });
-                        let Some((bound_vars, assoc_item)) = one_bound else {
+                            });
+
+                        let Some((bound_vars, assoc_item)) = bounds.next() else {
+                            // This will error in HIR lowering.
+                            self.tcx
+                                .dcx()
+                                .span_delayed_bug(path.span, "no resolution for RTN path");
                             return;
                         };
+
+                        // Don't bail if we have identical bounds, which may be collected from
+                        // something like `T: Bound + Bound`, or via elaborating supertraits.
+                        for (second_vars, second_assoc_item) in bounds {
+                            if second_vars != bound_vars || second_assoc_item != assoc_item {
+                                // This will error in HIR lowering.
+                                self.tcx.dcx().span_delayed_bug(
+                                    path.span,
+                                    "ambiguous resolution for RTN path",
+                                );
+                                return;
+                            }
+                        }
+
                         (bound_vars, assoc_item.def_id, item_segment)
                     }
                     // If we have a self type alias (in an impl), try to resolve an
@@ -2167,6 +2156,92 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
         existing_bound_vars.extend(bound_vars);
         self.record_late_bound_vars(item_segment.hir_id, existing_bound_vars_saved);
     }
+
+    /// Walk the generics of the item for a trait bound whose self type
+    /// corresponds to the expected res, and return the trait def id.
+    fn for_each_trait_bound_on_res(
+        &self,
+        expected_res: Res,
+    ) -> impl Iterator<Item = DefId> + use<'tcx, '_> {
+        std::iter::from_coroutine(
+            #[coroutine]
+            move || {
+                let mut scope = self.scope;
+                loop {
+                    let hir_id = match *scope {
+                        Scope::Binder { hir_id, .. } => Some(hir_id),
+                        Scope::Root { opt_parent_item: Some(parent_def_id) } => {
+                            Some(self.tcx.local_def_id_to_hir_id(parent_def_id))
+                        }
+                        Scope::Body { .. }
+                        | Scope::ObjectLifetimeDefault { .. }
+                        | Scope::Supertrait { .. }
+                        | Scope::TraitRefBoundary { .. }
+                        | Scope::LateBoundary { .. }
+                        | Scope::Opaque { .. }
+                        | Scope::Root { opt_parent_item: None } => None,
+                    };
+
+                    if let Some(hir_id) = hir_id {
+                        let node = self.tcx.hir_node(hir_id);
+                        // If this is a `Self` bound in a trait, yield the trait itself.
+                        // Specifically, we don't need to look at any supertraits since
+                        // we already do that in `BoundVarContext::supertrait_hrtb_vars`.
+                        if let Res::SelfTyParam { trait_: _ } = expected_res
+                            && let hir::Node::Item(item) = node
+                            && let hir::ItemKind::Trait(..) = item.kind
+                        {
+                            // Yield the trait's def id. Supertraits will be
+                            // elaborated from that.
+                            yield item.owner_id.def_id.to_def_id();
+                        } else if let Some(generics) = node.generics() {
+                            for pred in generics.predicates {
+                                let hir::WherePredicateKind::BoundPredicate(pred) = pred.kind
+                                else {
+                                    continue;
+                                };
+                                let hir::TyKind::Path(hir::QPath::Resolved(None, bounded_path)) =
+                                    pred.bounded_ty.kind
+                                else {
+                                    continue;
+                                };
+                                // Match the expected res.
+                                if bounded_path.res != expected_res {
+                                    continue;
+                                }
+                                for pred in pred.bounds {
+                                    match pred {
+                                        hir::GenericBound::Trait(poly_trait_ref) => {
+                                            if let Some(def_id) =
+                                                poly_trait_ref.trait_ref.trait_def_id()
+                                            {
+                                                yield def_id;
+                                            }
+                                        }
+                                        hir::GenericBound::Outlives(_)
+                                        | hir::GenericBound::Use(_, _) => {}
+                                    }
+                                }
+                            }
+                        }
+                    }
+
+                    match *scope {
+                        Scope::Binder { s, .. }
+                        | Scope::Body { s, .. }
+                        | Scope::ObjectLifetimeDefault { s, .. }
+                        | Scope::Supertrait { s, .. }
+                        | Scope::TraitRefBoundary { s }
+                        | Scope::LateBoundary { s, .. }
+                        | Scope::Opaque { s, .. } => {
+                            scope = s;
+                        }
+                        Scope::Root { .. } => break,
+                    }
+                }
+            },
+        )
+    }
 }
 
 /// Detects late-bound lifetimes and inserts them into

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -219,11 +219,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             def_ids.retain(|def_id| !tcx.generics_require_sized_self(def_id));
         }
 
-        self.complain_about_missing_assoc_tys(
+        if let Err(guar) = self.check_for_required_assoc_tys(
             associated_types,
             potential_assoc_types,
             hir_trait_bounds,
-        );
+        ) {
+            return Ty::new_error(tcx, guar);
+        }
 
         // De-duplicate auto traits so that, e.g., `dyn Trait + Send + Send` is the same as
         // `dyn Trait + Send`.

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -714,14 +714,14 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     /// reasonable suggestion on how to write it. For the case of multiple associated types in the
     /// same trait bound have the same name (as they come from different supertraits), we instead
     /// emit a generic note suggesting using a `where` clause to constraint instead.
-    pub(crate) fn complain_about_missing_assoc_tys(
+    pub(crate) fn check_for_required_assoc_tys(
         &self,
         associated_types: FxIndexMap<Span, FxIndexSet<DefId>>,
         potential_assoc_types: Vec<usize>,
         trait_bounds: &[hir::PolyTraitRef<'_>],
-    ) {
+    ) -> Result<(), ErrorGuaranteed> {
         if associated_types.values().all(|v| v.is_empty()) {
-            return;
+            return Ok(());
         }
 
         let tcx = self.tcx();
@@ -739,7 +739,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // Account for things like `dyn Foo + 'a`, like in tests `issue-22434.rs` and
         // `issue-22560.rs`.
         let mut trait_bound_spans: Vec<Span> = vec![];
-        let mut dyn_compatibility_violations = false;
+        let mut dyn_compatibility_violations = Ok(());
         for (span, items) in &associated_types {
             if !items.is_empty() {
                 trait_bound_spans.push(*span);
@@ -752,13 +752,20 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 let violations =
                     dyn_compatibility_violations_for_assoc_item(tcx, trait_def_id, *assoc_item);
                 if !violations.is_empty() {
-                    report_dyn_incompatibility(tcx, *span, None, trait_def_id, &violations).emit();
-                    dyn_compatibility_violations = true;
+                    dyn_compatibility_violations = Err(report_dyn_incompatibility(
+                        tcx,
+                        *span,
+                        None,
+                        trait_def_id,
+                        &violations,
+                    )
+                    .emit());
                 }
             }
         }
-        if dyn_compatibility_violations {
-            return;
+
+        if let Err(guar) = dyn_compatibility_violations {
+            return Err(guar);
         }
 
         // related to issue #91997, turbofishes added only when in an expr or pat
@@ -965,7 +972,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             }
         }
 
-        err.emit();
+        Err(err.emit())
     }
 
     /// On ambiguous associated type, look for an associated function whose name matches the

compiler/rustc_hir_analysis/src/lib.rs

@@ -62,7 +62,9 @@ This API is completely unstable and subject to change.
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
+#![feature(coroutines)]
 #![feature(if_let_guard)]
+#![feature(iter_from_coroutine)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
 #![feature(never_type)]

compiler/rustc_lint/messages.ftl

@@ -450,15 +450,15 @@ lint_invalid_nan_comparisons_eq_ne = incorrect NaN comparison, NaN cannot be dir
 lint_invalid_nan_comparisons_lt_le_gt_ge = incorrect NaN comparison, NaN is not orderable
 
 lint_invalid_reference_casting_assign_to_ref = assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
-    .label = casting happend here
+    .label = casting happened here
 
 lint_invalid_reference_casting_bigger_layout = casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
-    .label = casting happend here
+    .label = casting happened here
     .alloc = backing allocation comes from here
     .layout = casting from `{$from_ty}` ({$from_size} bytes) to `{$to_ty}` ({$to_size} bytes)
 
 lint_invalid_reference_casting_borrow_as_mut = casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
-    .label = casting happend here
+    .label = casting happened here
 
 lint_invalid_reference_casting_note_book = for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
 

compiler/rustc_span/src/symbol.rs

@@ -182,6 +182,7 @@ symbols! {
         ConstParamTy_,
         Context,
         Continue,
+        ControlFlow,
         Copy,
         Cow,
         Debug,

library/Cargo.lock

@@ -158,9 +158,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.162"
+version = "0.2.167"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "18d287de67fe55fd7e1581fe933d965a5a9477b38e949cfa9f8574ef01506398"
+checksum = "09d6582e104315a817dff97f75133544b2e094ee22447d2acf4a74e189ba06fc"
 dependencies = [
  "rustc-std-workspace-core",
 ]

library/core/src/ops/control_flow.rs

@@ -79,6 +79,7 @@ use crate::{convert, ops};
 /// [`Break`]: ControlFlow::Break
 /// [`Continue`]: ControlFlow::Continue
 #[stable(feature = "control_flow_enum_type", since = "1.55.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "ControlFlow")]
 // ControlFlow should not implement PartialOrd or Ord, per RFC 3058:
 // https://rust-lang.github.io/rfcs/3058-try-trait-v2.html#traits-for-controlflow
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]

library/panic_unwind/src/gcc.rs

@@ -5,7 +5,7 @@
 //! documents linked from it.
 //! These are also good reads:
 //!  * <https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html>
-//!  * <https://monoinfinito.wordpress.com/series/exception-handling-in-c/>
+//!  * <https://nicolasbrailo.github.io/blog/projects_texts/13exceptionsunderthehood.html>
 //!  * <https://www.airs.com/blog/index.php?s=exception+frames>
 //!
 //! ## A brief summary

library/std/Cargo.toml

@@ -34,7 +34,7 @@ miniz_oxide = { version = "0.7.0", optional = true, default-features = false }
 addr2line = { version = "0.22.0", optional = true, default-features = false }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
-libc = { version = "0.2.162", default-features = false, features = [
+libc = { version = "0.2.167", default-features = false, features = [
     'rustc-dep-of-std',
 ], public = true }