Rollup of 5 pull requests

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -1681,7 +1681,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || found_assoc(tcx.types.u64)
             || found_assoc(tcx.types.u128)
             || found_assoc(tcx.types.f32)
-            || found_assoc(tcx.types.f32);
+            || found_assoc(tcx.types.f64);
         if found_candidate
             && actual.is_numeric()
             && !actual.has_concrete_skeleton()

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -29,25 +29,15 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         // version new_ty of its type where the anonymous region is replaced
         // with the named one.
         let (named, anon, anon_param_info, region_info) = if sub.has_name()
-            && self.tcx().is_suitable_region(sup).is_some()
-            && self.find_param_with_region(sup, sub).is_some()
+            && let Some(region_info) = self.tcx().is_suitable_region(sup)
+            && let Some(anon_param_info) = self.find_param_with_region(sup, sub)
         {
-            (
-                sub,
-                sup,
-                self.find_param_with_region(sup, sub).unwrap(),
-                self.tcx().is_suitable_region(sup).unwrap(),
-            )
+            (sub, sup, anon_param_info, region_info)
         } else if sup.has_name()
-            && self.tcx().is_suitable_region(sub).is_some()
-            && self.find_param_with_region(sub, sup).is_some()
+            && let Some(region_info) = self.tcx().is_suitable_region(sub)
+            && let Some(anon_param_info) = self.find_param_with_region(sub, sup)
         {
-            (
-                sup,
-                sub,
-                self.find_param_with_region(sub, sup).unwrap(),
-                self.tcx().is_suitable_region(sub).unwrap(),
-            )
+            (sup, sub, anon_param_info, region_info)
         } else {
             return None; // inapplicable
         };

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs

@@ -64,7 +64,7 @@ pub fn find_param_with_region<'tcx>(
     let body_id = hir.maybe_body_owned_by(def_id)?;
 
     let owner_id = hir.body_owner(body_id);
-    let fn_decl = hir.fn_decl_by_hir_id(owner_id).unwrap();
+    let fn_decl = hir.fn_decl_by_hir_id(owner_id)?;
     let poly_fn_sig = tcx.fn_sig(id).instantiate_identity();
 
     let fn_sig = tcx.liberate_late_bound_regions(id, poly_fn_sig);

compiler/rustc_lint/src/reference_casting.rs

@@ -98,32 +98,56 @@ impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
 fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> bool {
     let e = e.peel_blocks();
 
-    // <expr> as *mut ...
-    let e = if let ExprKind::Cast(e, t) = e.kind
-        && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(t.hir_id).kind() {
-        e
-    // <expr>.cast_mut()
-    } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
-        && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
-        && cx.tcx.is_diagnostic_item(sym::ptr_cast_mut, def_id) {
-        expr
-    } else {
-        return false;
-    };
+    fn from_casts<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
+        // <expr> as *mut ...
+        let e = if let ExprKind::Cast(e, t) = e.kind
+            && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(t.hir_id).kind() {
+            e
+        // <expr>.cast_mut()
+        } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
+            && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
+            && cx.tcx.is_diagnostic_item(sym::ptr_cast_mut, def_id) {
+            expr
+        } else {
+            return None;
+        };
 
-    let e = e.peel_blocks();
+        let e = e.peel_blocks();
+
+        // <expr> as *const ...
+        let e = if let ExprKind::Cast(e, t) = e.kind
+            && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Not, .. }) = cx.typeck_results().node_type(t.hir_id).kind() {
+            e
+        // ptr::from_ref(<expr>)
+        } else if let ExprKind::Call(path, [arg]) = e.kind
+            && let ExprKind::Path(ref qpath) = path.kind
+            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
+            && cx.tcx.is_diagnostic_item(sym::ptr_from_ref, def_id) {
+            arg
+        } else {
+            return None;
+        };
+
+        Some(e)
+    }
+
+    fn from_transmute<'tcx>(
+        cx: &LateContext<'tcx>,
+        e: &'tcx Expr<'tcx>,
+    ) -> Option<&'tcx Expr<'tcx>> {
+        // mem::transmute::<_, *mut _>(<expr>)
+        if let ExprKind::Call(path, [arg]) = e.kind
+            && let ExprKind::Path(ref qpath) = path.kind
+            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
+            && cx.tcx.is_diagnostic_item(sym::transmute, def_id)
+            && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(e.hir_id).kind() {
+            Some(arg)
+        } else {
+            None
+        }
+    }
 
-    // <expr> as *const ...
-    let e = if let ExprKind::Cast(e, t) = e.kind
-        && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Not, .. }) = cx.typeck_results().node_type(t.hir_id).kind() {
-        e
-    // ptr::from_ref(<expr>)
-    } else if let ExprKind::Call(path, [arg]) = e.kind
-        && let ExprKind::Path(ref qpath) = path.kind
-        && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
-        && cx.tcx.is_diagnostic_item(sym::ptr_from_ref, def_id) {
-        arg
-    } else {
+    let Some(e) = from_casts(cx, e).or_else(|| from_transmute(cx, e)) else {
         return false;
     };
 

compiler/rustc_trait_selection/src/solve/assembly/mod.rs

@@ -316,6 +316,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
         self.assemble_param_env_candidates(goal, &mut candidates);
 
+        self.assemble_coherence_unknowable_candidates(goal, &mut candidates);
+
         candidates
     }
 
@@ -363,10 +365,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
         self.assemble_object_bound_candidates(goal, &mut candidates);
 
-        self.assemble_coherence_unknowable_candidates(goal, &mut candidates);
-
         self.assemble_candidates_after_normalizing_self_ty(goal, &mut candidates, num_steps);
-
         candidates
     }
 
@@ -877,26 +876,43 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         goal: Goal<'tcx, G>,
         candidates: &mut Vec<Candidate<'tcx>>,
     ) {
+        let tcx = self.tcx();
         match self.solver_mode() {
             SolverMode::Normal => return,
-            SolverMode::Coherence => {
-                let trait_ref = goal.predicate.trait_ref(self.tcx());
-                match coherence::trait_ref_is_knowable(self.tcx(), trait_ref) {
-                    Ok(()) => {}
-                    Err(_) => match self
-                        .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
-                    {
-                        Ok(result) => candidates.push(Candidate {
-                            source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
-                            result,
-                        }),
-                        // FIXME: This will be reachable at some point if we're in
-                        // `assemble_candidates_after_normalizing_self_ty` and we get a
-                        // universe error. We'll deal with it at this point.
-                        Err(NoSolution) => bug!("coherence candidate resulted in NoSolution"),
-                    },
+            SolverMode::Coherence => {}
+        };
+
+        let result = self.probe_candidate("coherence unknowable").enter(|ecx| {
+            let trait_ref = goal.predicate.trait_ref(tcx);
+
+            #[derive(Debug)]
+            enum FailureKind {
+                Overflow,
+                NoSolution(NoSolution),
+            }
+            let lazily_normalize_ty = |ty| match ecx.try_normalize_ty(goal.param_env, ty) {
+                Ok(Some(ty)) => Ok(ty),
+                Ok(None) => Err(FailureKind::Overflow),
+                Err(e) => Err(FailureKind::NoSolution(e)),
+            };
+
+            match coherence::trait_ref_is_knowable(tcx, trait_ref, lazily_normalize_ty) {
+                Err(FailureKind::Overflow) => {
+                    ecx.evaluate_added_goals_and_make_canonical_response(Certainty::OVERFLOW)
+                }
+                Err(FailureKind::NoSolution(NoSolution)) | Ok(Ok(())) => Err(NoSolution),
+                Ok(Err(_)) => {
+                    ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
                 }
             }
+        });
+
+        match result {
+            Ok(result) => candidates.push(Candidate {
+                source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
+                result,
+            }),
+            Err(NoSolution) => {}
         }
     }
 

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -388,44 +388,60 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
             && is_normalizes_to_hack == IsNormalizesToHack::No
             && !self.search_graph.in_cycle()
         {
-            debug!("rerunning goal to check result is stable");
-            self.search_graph.reset_encountered_overflow(encountered_overflow);
-            let (_orig_values, canonical_goal) = self.canonicalize_goal(goal);
-            let Ok(new_canonical_response) = EvalCtxt::evaluate_canonical_goal(
-                self.tcx(),
-                self.search_graph,
-                canonical_goal,
-                // FIXME(-Ztrait-solver=next): we do not track what happens in `evaluate_canonical_goal`
-                &mut ProofTreeBuilder::new_noop(),
-            ) else {
-                bug!(
-                    "goal went from {certainty:?} to error: re-canonicalized goal={canonical_goal:#?} \
-                    first_response={canonical_response:#?},
-                    second response was error"
-                );
-            };
-            // We only check for modulo regions as we convert all regions in
-            // the input to new existentials, even if they're expected to be
-            // `'static` or a placeholder region.
-            if !new_canonical_response.value.var_values.is_identity_modulo_regions() {
-                bug!(
-                    "unstable result: re-canonicalized goal={canonical_goal:#?} \
-                    first_response={canonical_response:#?} \
-                    second_response={new_canonical_response:#?}"
-                );
-            }
-            if certainty != new_canonical_response.value.certainty {
-                bug!(
-                    "unstable certainty: {certainty:#?} re-canonicalized goal={canonical_goal:#?} \
-                     first_response={canonical_response:#?} \
-                     second_response={new_canonical_response:#?}"
-                );
-            }
+            // The nested evaluation has to happen with the original state
+            // of `encountered_overflow`.
+            let from_original_evaluation =
+                self.search_graph.reset_encountered_overflow(encountered_overflow);
+            self.check_evaluate_goal_stable_result(goal, canonical_goal, canonical_response);
+            // In case the evaluation was unstable, we manually make sure that this
+            // debug check does not influence the result of the parent goal.
+            self.search_graph.reset_encountered_overflow(from_original_evaluation);
         }
 
         Ok((has_changed, certainty, nested_goals))
     }
 
+    fn check_evaluate_goal_stable_result(
+        &mut self,
+        goal: Goal<'tcx, ty::Predicate<'tcx>>,
+        original_input: CanonicalInput<'tcx>,
+        original_result: CanonicalResponse<'tcx>,
+    ) {
+        let (_orig_values, canonical_goal) = self.canonicalize_goal(goal);
+        let result = EvalCtxt::evaluate_canonical_goal(
+            self.tcx(),
+            self.search_graph,
+            canonical_goal,
+            // FIXME(-Ztrait-solver=next): we do not track what happens in `evaluate_canonical_goal`
+            &mut ProofTreeBuilder::new_noop(),
+        );
+
+        macro_rules! fail {
+            ($msg:expr) => {{
+                let msg = $msg;
+                warn!(
+                    "unstable result: {msg}\n\
+                    original goal: {original_input:?},\n\
+                    original result: {original_result:?}\n\
+                    re-canonicalized goal: {canonical_goal:?}\n\
+                    second response: {result:?}"
+                );
+                return;
+            }};
+        }
+
+        let Ok(new_canonical_response) = result else { fail!("second response was error") };
+        // We only check for modulo regions as we convert all regions in
+        // the input to new existentials, even if they're expected to be
+        // `'static` or a placeholder region.
+        if !new_canonical_response.value.var_values.is_identity_modulo_regions() {
+            fail!("additional constraints from second response")
+        }
+        if original_result.value.certainty != new_canonical_response.value.certainty {
+            fail!("unstable certainty")
+        }
+    }
+
     fn compute_goal(&mut self, goal: Goal<'tcx, ty::Predicate<'tcx>>) -> QueryResult<'tcx> {
         let Goal { param_env, predicate } = goal;
         let kind = predicate.kind();

compiler/rustc_trait_selection/src/solve/mod.rs

@@ -283,6 +283,37 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
         Ok(self.make_ambiguous_response_no_constraints(maybe_cause))
     }
+
+    /// Normalize a type when it is structually matched on.
+    ///
+    /// For self types this is generally already handled through
+    /// `assemble_candidates_after_normalizing_self_ty`, so anything happening
+    /// in [`EvalCtxt::assemble_candidates_via_self_ty`] does not have to normalize
+    /// the self type. It is required when structurally matching on any other
+    /// arguments of a trait goal, e.g. when assembling builtin unsize candidates.
+    fn try_normalize_ty(
+        &mut self,
+        param_env: ty::ParamEnv<'tcx>,
+        mut ty: Ty<'tcx>,
+    ) -> Result<Option<Ty<'tcx>>, NoSolution> {
+        for _ in 0..self.local_overflow_limit() {
+            let ty::Alias(_, projection_ty) = *ty.kind() else {
+                return Ok(Some(ty));
+            };
+
+            let normalized_ty = self.next_ty_infer();
+            let normalizes_to_goal = Goal::new(
+                self.tcx(),
+                param_env,
+                ty::ProjectionPredicate { projection_ty, term: normalized_ty.into() },
+            );
+            self.add_goal(normalizes_to_goal);
+            self.try_evaluate_added_goals()?;
+            ty = self.resolve_vars_if_possible(normalized_ty);
+        }
+
+        Ok(None)
+    }
 }
 
 fn response_no_constraints_raw<'tcx>(

compiler/rustc_trait_selection/src/solve/search_graph/mod.rs

@@ -134,9 +134,13 @@ impl<'tcx> SearchGraph<'tcx> {
     /// Resets `encountered_overflow` of the current goal.
     ///
     /// This should only be used for the check in `evaluate_goal`.
-    pub(super) fn reset_encountered_overflow(&mut self, encountered_overflow: bool) {
-        if encountered_overflow {
-            self.stack.raw.last_mut().unwrap().encountered_overflow = true;
+    pub(super) fn reset_encountered_overflow(&mut self, encountered_overflow: bool) -> bool {
+        if let Some(last) = self.stack.raw.last_mut() {
+            let prev = last.encountered_overflow;
+            last.encountered_overflow = encountered_overflow;
+            prev
+        } else {
+            false
         }
     }