Rollup of 4 pull requests

compiler/rustc_trait_selection/src/solve/alias_relate.rs

@@ -20,7 +20,7 @@ use rustc_middle::traits::solve::{Certainty, Goal, QueryResult};
 use rustc_middle::ty;
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn compute_alias_relate_goal(
         &mut self,
         goal: Goal<'tcx, (ty::Term<'tcx>, ty::Term<'tcx>, ty::AliasRelationDirection)>,
@@ -50,7 +50,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         self.try_evaluate_added_goals()?;
         let lhs = self.resolve_vars_if_possible(lhs);
         let rhs = self.resolve_vars_if_possible(rhs);
-        debug!(?lhs, ?rhs);
+        trace!(?lhs, ?rhs);
 
         let variance = match direction {
             ty::AliasRelationDirection::Equate => ty::Variance::Invariant,

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

@@ -331,7 +331,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             .enter(|this| this.evaluate_added_goals_and_make_canonical_response(certainty))
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_non_blanket_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -447,7 +447,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_blanket_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -470,7 +470,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_builtin_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -544,7 +544,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_param_env_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -561,7 +561,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_alias_bound_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -665,7 +665,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_object_bound_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -756,7 +756,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ///
     /// To do so we add an ambiguous candidate in case such an unknown impl could
     /// apply to the current goal.
-    #[instrument(level = "debug", skip_all)]
+    #[instrument(level = "trace", skip_all)]
     fn assemble_coherence_unknowable_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,

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

@@ -17,7 +17,7 @@ use crate::solve::EvalCtxt;
 //
 // For types with an "existential" binder, i.e. coroutine witnesses, we also
 // instantiate the binder with placeholders eagerly.
-#[instrument(level = "debug", skip(ecx), ret)]
+#[instrument(level = "trace", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,
@@ -96,7 +96,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
     }
 }
 
-#[instrument(level = "debug", skip(ecx), ret)]
+#[instrument(level = "trace", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,
@@ -160,7 +160,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
     }
 }
 
-#[instrument(level = "debug", skip(ecx), ret)]
+#[instrument(level = "trace", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     ty: Ty<'tcx>,

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

@@ -83,7 +83,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ///   the values inferred while solving the instantiated goal.
     /// - `external_constraints`: additional constraints which aren't expressible
     ///   using simple unification of inference variables.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(in crate::solve) fn evaluate_added_goals_and_make_canonical_response(
         &mut self,
         certainty: Certainty,
@@ -166,15 +166,15 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// external constraints do not need to record that opaque, since if it is
     /// further constrained by inference, that will be passed back in the var
     /// values.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn compute_external_query_constraints(
         &self,
         normalization_nested_goals: NestedNormalizationGoals<'tcx>,
     ) -> Result<ExternalConstraintsData<'tcx>, NoSolution> {
         // We only check for leaks from universes which were entered inside
         // of the query.
         self.infcx.leak_check(self.max_input_universe, None).map_err(|e| {
-            debug!(?e, "failed the leak check");
+            trace!(?e, "failed the leak check");
             NoSolution
         })?;
 
@@ -334,7 +334,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// whether an alias is rigid by using the trait solver. When instantiating a response
     /// from the solver we assume that the solver correctly handled aliases and therefore
     /// always relate them structurally here.
-    #[instrument(level = "debug", skip(infcx))]
+    #[instrument(level = "trace", skip(infcx))]
     fn unify_query_var_values(
         infcx: &InferCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
@@ -407,7 +407,7 @@ pub(in crate::solve) fn make_canonical_state<'tcx, T: TypeFoldable<TyCtxt<'tcx>>
 /// This currently assumes that unifying the var values trivially succeeds.
 /// Adding any inference constraints which weren't present when originally
 /// computing the canonical query can result in bugs.
-#[instrument(level = "debug", skip(infcx, span, param_env))]
+#[instrument(level = "trace", skip(infcx, span, param_env))]
 pub(in crate::solve) fn instantiate_canonical_state<'tcx, T: TypeFoldable<TyCtxt<'tcx>>>(
     infcx: &InferCtxt<'tcx>,
     span: Span,

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

@@ -458,7 +458,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     pub(super) fn add_normalizes_to_goal(&mut self, goal: Goal<'tcx, ty::NormalizesTo<'tcx>>) {
         self.inspect.add_normalizes_to_goal(self.infcx, self.max_input_universe, goal);
         self.nested_goals.normalizes_to_goals.push(goal);
@@ -472,7 +472,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
 
     // Recursively evaluates all the goals added to this `EvalCtxt` to completion, returning
     // the certainty of all the goals.
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     pub(super) fn try_evaluate_added_goals(&mut self) -> Result<Certainty, NoSolution> {
         self.inspect.start_evaluate_added_goals();
         let mut response = Ok(Certainty::overflow(false));
@@ -526,7 +526,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                 unconstrained_goal,
             )?;
             // Add the nested goals from normalization to our own nested goals.
-            debug!(?nested_goals);
+            trace!(?nested_goals);
             goals.goals.extend(nested_goals);
 
             // Finally, equate the goal's RHS with the unconstrained var.
@@ -622,7 +622,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ///
     /// This is the case if the `term` does not occur in any other part of the predicate
     /// and is able to name all other placeholder and inference variables.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn term_is_fully_unconstrained(
         &self,
         goal: Goal<'tcx, ty::NormalizesTo<'tcx>>,
@@ -718,7 +718,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             && goal.param_env.visit_with(&mut visitor).is_continue()
     }
 
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn eq<T: ToTrace<'tcx>>(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -733,7 +733,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 self.add_goals(GoalSource::Misc, obligations.into_iter().map(|o| o.into()));
             })
             .map_err(|e| {
-                debug!(?e, "failed to equate");
+                trace!(?e, "failed to equate");
                 NoSolution
             })
     }
@@ -743,7 +743,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// Normally we emit a nested `AliasRelate` when equating an inference
     /// variable and an alias. This causes us to instead constrain the inference
     /// variable to the alias without emitting a nested alias relate goals.
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn relate_rigid_alias_non_alias(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -781,7 +781,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// This sohuld only be used when we're either instantiating a previously
     /// unconstrained "return value" or when we're sure that all aliases in
     /// the types are rigid.
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn eq_structurally_relating_aliases<T: ToTrace<'tcx>>(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -798,7 +798,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         Ok(())
     }
 
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn sub<T: ToTrace<'tcx>>(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -813,12 +813,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 self.add_goals(GoalSource::Misc, obligations.into_iter().map(|o| o.into()));
             })
             .map_err(|e| {
-                debug!(?e, "failed to subtype");
+                trace!(?e, "failed to subtype");
                 NoSolution
             })
     }
 
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn relate<T: ToTrace<'tcx>>(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -834,7 +834,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 self.add_goals(GoalSource::Misc, obligations.into_iter().map(|o| o.into()));
             })
             .map_err(|e| {
-                debug!(?e, "failed to relate");
+                trace!(?e, "failed to relate");
                 NoSolution
             })
     }
@@ -859,7 +859,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 obligations.into_iter().map(|o| o.into()).collect()
             })
             .map_err(|e| {
-                debug!(?e, "failed to equate");
+                trace!(?e, "failed to equate");
                 NoSolution
             })
     }

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

@@ -58,6 +58,7 @@ impl<'tcx, F> TraitProbeCtxt<'_, '_, 'tcx, F>
 where
     F: FnOnce(&QueryResult<'tcx>) -> inspect::ProbeKind<'tcx>,
 {
+    #[instrument(level = "debug", skip_all, fields(source = ?self.source))]
     pub(in crate::solve) fn enter(
         self,
         f: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,

compiler/rustc_trait_selection/src/solve/fulfill.rs

@@ -119,7 +119,7 @@ impl<'tcx> FulfillmentCtxt<'tcx> {
 }
 
 impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
-    #[instrument(level = "debug", skip(self, infcx))]
+    #[instrument(level = "trace", skip(self, infcx))]
     fn register_predicate_obligation(
         &mut self,
         infcx: &InferCtxt<'tcx>,

compiler/rustc_trait_selection/src/solve/mod.rs

@@ -82,7 +82,7 @@ impl<'tcx> Canonical<'tcx, Response<'tcx>> {
 }
 
 impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_type_outlives_goal(
         &mut self,
         goal: Goal<'tcx, TypeOutlivesPredicate<'tcx>>,
@@ -92,7 +92,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_region_outlives_goal(
         &mut self,
         goal: Goal<'tcx, RegionOutlivesPredicate<'tcx>>,
@@ -102,7 +102,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_coerce_goal(
         &mut self,
         goal: Goal<'tcx, CoercePredicate<'tcx>>,
@@ -117,7 +117,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         })
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_subtype_goal(
         &mut self,
         goal: Goal<'tcx, SubtypePredicate<'tcx>>,
@@ -138,7 +138,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_well_formed_goal(
         &mut self,
         goal: Goal<'tcx, ty::GenericArg<'tcx>>,
@@ -152,7 +152,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn compute_const_evaluatable_goal(
         &mut self,
         Goal { param_env, predicate: ct }: Goal<'tcx, ty::Const<'tcx>>,
@@ -189,7 +189,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn compute_const_arg_has_type_goal(
         &mut self,
         goal: Goal<'tcx, (ty::Const<'tcx>, Ty<'tcx>)>,
@@ -201,7 +201,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
-    #[instrument(level = "debug", skip(self, goals))]
+    #[instrument(level = "trace", skip(self, goals))]
     fn add_goals(
         &mut self,
         source: GoalSource,
@@ -215,7 +215,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// Try to merge multiple possible ways to prove a goal, if that is not possible returns `None`.
     ///
     /// In this case we tend to flounder and return ambiguity by calling `[EvalCtxt::flounder]`.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn try_merge_responses(
         &mut self,
         responses: &[CanonicalResponse<'tcx>],
@@ -241,7 +241,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     }
 
     /// If we fail to merge responses we flounder and return overflow or ambiguity.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn flounder(&mut self, responses: &[CanonicalResponse<'tcx>]) -> QueryResult<'tcx> {
         if responses.is_empty() {
             return Err(NoSolution);
@@ -263,7 +263,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// This function is necessary in nearly all cases before matching on a type.
     /// Not doing so is likely to be incomplete and therefore unsound during
     /// coherence.
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     fn structurally_normalize_ty(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_trait_selection/src/solve/normalize.rs

@@ -162,7 +162,7 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for NormalizationFolder<'_, 'tcx> {
         Ok(t)
     }
 
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn try_fold_ty(&mut self, ty: Ty<'tcx>) -> Result<Ty<'tcx>, Self::Error> {
         let infcx = self.at.infcx;
         debug_assert_eq!(ty, infcx.shallow_resolve(ty));
@@ -189,7 +189,7 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for NormalizationFolder<'_, 'tcx> {
         }
     }
 
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn try_fold_const(&mut self, ct: ty::Const<'tcx>) -> Result<ty::Const<'tcx>, Self::Error> {
         let infcx = self.at.infcx;
         debug_assert_eq!(ct, infcx.shallow_resolve_const(ct));

compiler/rustc_trait_selection/src/solve/normalizes_to/anon_const.rs

@@ -3,7 +3,7 @@ use rustc_middle::traits::solve::{Certainty, Goal, QueryResult};
 use rustc_middle::ty;
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn normalize_anon_const(
         &mut self,
         goal: Goal<'tcx, ty::NormalizesTo<'tcx>>,

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

@@ -25,7 +25,7 @@ mod opaque_types;
 mod weak_types;
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn compute_normalizes_to_goal(
         &mut self,
         goal: Goal<'tcx, NormalizesTo<'tcx>>,
@@ -59,7 +59,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
     /// Normalize the given alias by at least one step. If the alias is rigid, this
     /// returns `NoSolution`.
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     fn normalize_at_least_one_step(
         &mut self,
         goal: Goal<'tcx, NormalizesTo<'tcx>>,
@@ -897,7 +897,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
 ///
 /// FIXME: We should merge these 3 implementations as it's likely that they otherwise
 /// diverge.
-#[instrument(level = "debug", skip(ecx, param_env), ret)]
+#[instrument(level = "trace", skip(ecx, param_env), ret)]
 fn fetch_eligible_assoc_item_def<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -920,7 +920,7 @@ fn fetch_eligible_assoc_item_def<'tcx>(
             let poly_trait_ref = ecx.resolve_vars_if_possible(goal_trait_ref);
             !poly_trait_ref.still_further_specializable()
         } else {
-            debug!(?node_item.item.def_id, "not eligible due to default");
+            trace!(?node_item.item.def_id, "not eligible due to default");
             false
         }
     };

compiler/rustc_trait_selection/src/solve/project_goals.rs

@@ -5,7 +5,7 @@ use rustc_middle::traits::solve::{Certainty, Goal, QueryResult};
 use rustc_middle::ty::{self, ProjectionPredicate};
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
-    #[instrument(level = "debug", skip(self), ret)]
+    #[instrument(level = "trace", skip(self), ret)]
     pub(super) fn compute_projection_goal(
         &mut self,
         goal: Goal<'tcx, ProjectionPredicate<'tcx>>,

compiler/rustc_trait_selection/src/solve/search_graph.rs

@@ -130,7 +130,7 @@ impl<'tcx> SearchGraph<'tcx> {
     }
 
     /// Update the stack and reached depths on cache hits.
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn on_cache_hit(&mut self, additional_depth: usize, encountered_overflow: bool) {
         let reached_depth = self.stack.next_index().plus(additional_depth);
         if let Some(last) = self.stack.raw.last_mut() {
@@ -296,6 +296,7 @@ impl<'tcx> SearchGraph<'tcx> {
             }
 
             self.on_cache_hit(reached_depth, encountered_overflow);
+            debug!("global cache hit");
             return result;
         }
 
@@ -315,6 +316,7 @@ impl<'tcx> SearchGraph<'tcx> {
                     .filter(|p| !Self::stack_coinductive_from(tcx, &self.stack, p.head))
             })
         {
+            debug!("provisional cache hit");
             // We have a nested goal which is already in the provisional cache, use
             // its result. We do not provide any usage kind as that should have been
             // already set correctly while computing the cache entry.

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -1130,7 +1130,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                     },
                 );
                 if let Some(def_id) = disqualifying_impl {
-                    debug!(?def_id, ?goal, "disqualified auto-trait implementation");
+                    trace!(?def_id, ?goal, "disqualified auto-trait implementation");
                     // No need to actually consider the candidate here,
                     // since we do that in `consider_impl_candidate`.
                     return Some(Err(NoSolution));
@@ -1171,7 +1171,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         })
     }
 
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     pub(super) fn compute_trait_goal(
         &mut self,
         goal: Goal<'tcx, TraitPredicate<'tcx>>,

library/core/src/primitive_docs.rs

@@ -1467,8 +1467,9 @@ mod prim_usize {}
 /// For all types, `T: ?Sized`, and for all `t: &T` or `t: &mut T`, when such values cross an API
 /// boundary, the following invariants must generally be upheld:
 ///
+/// * `t` is non-null
 /// * `t` is aligned to `align_of_val(t)`
-/// * `t` is dereferenceable for `size_of_val(t)` many bytes
+/// * if `size_of_val(t) > 0`, then `t` is dereferenceable for `size_of_val(t)` many bytes
 ///
 /// If `t` points at address `a`, being "dereferenceable" for N bytes means that the memory range
 /// `[a, a + N)` is all contained within a single [allocated object].

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -244,7 +244,6 @@ run-make/rlib-format-packed-bundled-libs-3/Makefile
 run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/rmeta-preferred/Makefile
 run-make/rustc-macro-dep-files/Makefile
-run-make/rustdoc-io-error/Makefile
 run-make/rustdoc-scrape-examples-invalid-expr/Makefile
 run-make/rustdoc-scrape-examples-macros/Makefile
 run-make/rustdoc-scrape-examples-multiple/Makefile

tests/codegen-units/partitioning/extern-drop-glue.rs

@@ -1,7 +1,4 @@
-//
-
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 // We specify opt-level=0 because `drop_in_place` is `Internal` when optimizing
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy

tests/codegen-units/partitioning/extern-generic.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=eager -Zshare-generics=y
 

tests/codegen-units/partitioning/incremental-merging.rs

@@ -1,5 +1,4 @@
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Ccodegen-units=3

tests/codegen-units/partitioning/inlining-from-extern-crate.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Zinline-in-all-cgus

tests/codegen-units/partitioning/local-drop-glue.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 // We specify opt-level=0 because `drop_in_place` is `Internal` when optimizing
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy

tests/codegen-units/partitioning/local-generic.rs

@@ -1,5 +1,4 @@
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=eager
 

tests/codegen-units/partitioning/local-inlining-but-not-all.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Zinline-in-all-cgus=no

tests/codegen-units/partitioning/local-inlining.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Zinline-in-all-cgus

tests/codegen-units/partitioning/local-transitive-inlining.rs

@@ -1,6 +1,4 @@
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Zinline-in-all-cgus

tests/codegen-units/partitioning/methods-are-with-self-type.rs

@@ -3,9 +3,7 @@
 // much sense at the moment.
 //@ ignore-test
 
-//
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 

tests/codegen-units/partitioning/regular-modules.rs

@@ -1,5 +1,4 @@
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=eager
 

tests/codegen-units/partitioning/shared-generics.rs

@@ -1,4 +1,3 @@
-//
 //@ no-prefer-dynamic
 // NOTE: We always compile this test with -Copt-level=0 because higher opt-levels
 //       prevent drop-glue from participating in share-generics.

tests/codegen-units/partitioning/statics.rs

@@ -1,5 +1,4 @@
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 

tests/codegen-units/partitioning/vtable-through-const.rs

@@ -1,7 +1,4 @@
-//
-
-// We specify incremental here because we want to test the partitioning for
-//@ incremental compilation
+// We specify incremental here because we want to test the partitioning for incremental compilation
 //@ incremental
 //@ compile-flags:-Zprint-mono-items=lazy
 //@ compile-flags:-Zinline-in-all-cgus

tests/run-make/rustdoc-io-error/rmake.rs

@@ -0,0 +1,32 @@
+// This test verifies that rustdoc doesn't ICE when it encounters an IO error
+// while generating files. Ideally this would be a rustdoc-ui test, so we could
+// verify the error message as well.
+//
+// It operates by creating a temporary directory and modifying its
+// permissions so that it is not writable. We have to take special care to set
+// the permissions back to normal so that it's able to be deleted later.
+
+use run_make_support::{rustdoc, tmp_dir};
+use std::fs;
+
+fn main() {
+    let out_dir = tmp_dir().join("rustdoc-io-error");
+    let output = fs::create_dir(&out_dir).unwrap();
+    let mut permissions = fs::metadata(&out_dir).unwrap().permissions();
+    permissions.set_readonly(true);
+    fs::set_permissions(&out_dir, permissions.clone()).unwrap();
+
+    let output = rustdoc().input("foo.rs").output(&out_dir).command_output();
+
+    // Changing back permissions.
+    permissions.set_readonly(false);
+    fs::set_permissions(&out_dir, permissions).unwrap();
+
+    // Checks that rustdoc failed with the error code 1.
+    #[cfg(target_os = "linux")]
+    assert_eq!(output.status.code().unwrap(), 1);
+    assert!(!output.status.success());
+    let stderr = String::from_utf8(output.stderr).unwrap();
+
+    assert!(stderr.contains("error: couldn't generate documentation: Permission denied"));
+}