Tweak debug outputs to make debugging new solver easier

compiler/rustc_middle/src/infer/canonical.rs

@@ -35,9 +35,9 @@ use std::ops::Index;
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable)]
 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct Canonical<'tcx, V> {
+    pub value: V,
     pub max_universe: ty::UniverseIndex,
     pub variables: CanonicalVarInfos<'tcx>,
-    pub value: V,
 }
 
 pub type CanonicalVarInfos<'tcx> = &'tcx List<CanonicalVarInfo<'tcx>>;

compiler/rustc_middle/src/traits/solve.rs

@@ -20,8 +20,8 @@ pub type EvaluationCache<'tcx> = Cache<CanonicalGoal<'tcx>, QueryResult<'tcx>>;
 /// we're currently typechecking while the `predicate` is some trait bound.
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
 pub struct Goal<'tcx, P> {
-    pub param_env: ty::ParamEnv<'tcx>,
     pub predicate: P,
+    pub param_env: ty::ParamEnv<'tcx>,
 }
 
 impl<'tcx, P> Goal<'tcx, P> {
@@ -41,10 +41,10 @@ impl<'tcx, P> Goal<'tcx, P> {
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
 pub struct Response<'tcx> {
+    pub certainty: Certainty,
     pub var_values: CanonicalVarValues<'tcx>,
     /// Additional constraints returned by this query.
     pub external_constraints: ExternalConstraints<'tcx>,
-    pub certainty: Certainty,
 }
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]

compiler/rustc_trait_selection/src/solve/assembly.rs

@@ -270,6 +270,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// To deal with this, we first try to normalize the self type and add the candidates for the normalized
     /// self type to the list of candidates in case that succeeds. We also have to consider candidates with the
     /// projection as a self type as well
+    #[instrument(level = "debug", skip_all)]
     fn assemble_candidates_after_normalizing_self_ty<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -315,6 +316,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -333,6 +335,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         );
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_builtin_impl_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -390,6 +393,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_param_env_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -405,6 +409,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_alias_bound_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -452,6 +457,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_object_bound_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,
@@ -514,6 +520,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip_all)]
     fn assemble_coherence_unknowable_candidates<G: GoalKind<'tcx>>(
         &mut self,
         goal: Goal<'tcx, G>,

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -106,7 +106,7 @@ pub trait InferCtxtEvalExt<'tcx> {
 }
 
 impl<'tcx> InferCtxtEvalExt<'tcx> for InferCtxt<'tcx> {
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn evaluate_root_goal(
         &self,
         goal: Goal<'tcx, ty::Predicate<'tcx>>,
@@ -552,7 +552,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ///
     /// If possible, try using `eq` instead which automatically handles nested
     /// goals correctly.
-    #[instrument(level = "debug", skip(self, param_env), ret)]
+    #[instrument(level = "trace", skip(self, param_env), ret)]
     pub(super) fn eq_and_get_goals<T: ToTrace<'tcx>>(
         &self,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_trait_selection/src/solve/mod.rs

@@ -153,13 +153,22 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
     ) -> QueryResult<'tcx> {
         let tcx = self.tcx();
         // We may need to invert the alias relation direction if dealing an alias on the RHS.
+        #[derive(Debug)]
         enum Invert {
             No,
             Yes,
         }
         let evaluate_normalizes_to =
             |ecx: &mut EvalCtxt<'_, 'tcx>, alias, other, direction, invert| {
-                debug!("evaluate_normalizes_to(alias={:?}, other={:?})", alias, other);
+                let span = tracing::span!(
+                    tracing::Level::DEBUG,
+                    "compute_alias_relate_goal(evaluate_normalizes_to)",
+                    ?alias,
+                    ?other,
+                    ?direction,
+                    ?invert
+                );
+                let _enter = span.enter();
                 let result = ecx.probe(|ecx| {
                     let other = match direction {
                         // This is purely an optimization.
@@ -184,7 +193,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                     ));
                     ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
                 });
-                debug!("evaluate_normalizes_to({alias}, {other}, {direction:?}) -> {result:?}");
+                debug!(?result);
                 result
             };
 
@@ -210,7 +219,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
             }
 
             (Some(alias_lhs), Some(alias_rhs)) => {
-                debug!("compute_alias_relate_goal: both sides are aliases");
+                debug!("both sides are aliases");
 
                 let candidates = vec![
                     // LHS normalizes-to RHS
@@ -219,9 +228,14 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                     evaluate_normalizes_to(self, alias_rhs, lhs, direction, Invert::Yes),
                     // Relate via substs
                     self.probe(|ecx| {
-                        debug!(
-                            "compute_alias_relate_goal: alias defids are equal, equating substs"
+                        let span = tracing::span!(
+                            tracing::Level::DEBUG,
+                            "compute_alias_relate_goal(relate_via_substs)",
+                            ?alias_lhs,
+                            ?alias_rhs,
+                            ?direction
                         );
+                        let _enter = span.enter();
 
                         match direction {
                             ty::AliasRelationDirection::Equate => {
@@ -275,6 +289,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         debug!("added_goals={:?}", &self.nested_goals.goals[current_len..]);
     }
 
+    #[instrument(level = "debug", skip(self, responses))]
     fn try_merge_responses(
         &mut self,
         responses: impl Iterator<Item = QueryResult<'tcx>>,
@@ -304,6 +319,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         });
         // FIXME(-Ztrait-solver=next): We should take the intersection of the constraints on all the
         // responses and use that for the constraints of this ambiguous response.
+        debug!(">1 response, bailing with {certainty:?}");
         let response = self.evaluate_added_goals_and_make_canonical_response(certainty);
         if let Ok(response) = &response {
             assert!(response.has_no_inference_or_external_constraints());

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

@@ -209,6 +209,7 @@ impl<'tcx> SearchGraph<'tcx> {
     ) -> QueryResult<'tcx> {
         if self.should_use_global_cache() {
             if let Some(result) = tcx.new_solver_evaluation_cache.get(&canonical_goal, tcx) {
+                debug!(?canonical_goal, ?result, "cache hit");
                 return result;
             }
         }

tests/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir

@@ -1,36 +1,36 @@
 // MIR for `address_of_reborrow` after SimplifyCfg-initial
 
 | User Type Annotations
-| 0: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:7:5: 7:18, inferred_ty: *const [i32; 10]
-| 1: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:9:5: 9:25, inferred_ty: *const dyn std::marker::Send
-| 2: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:13:12: 13:20, inferred_ty: *const [i32; 10]
-| 3: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:13:12: 13:20, inferred_ty: *const [i32; 10]
-| 4: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32; 10]) }, span: $DIR/address_of.rs:14:12: 14:28, inferred_ty: *const [i32; 10]
-| 5: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32; 10]) }, span: $DIR/address_of.rs:14:12: 14:28, inferred_ty: *const [i32; 10]
-| 6: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:15:12: 15:27, inferred_ty: *const dyn std::marker::Send
-| 7: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:15:12: 15:27, inferred_ty: *const dyn std::marker::Send
-| 8: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32]) }, span: $DIR/address_of.rs:16:12: 16:24, inferred_ty: *const [i32]
-| 9: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32]) }, span: $DIR/address_of.rs:16:12: 16:24, inferred_ty: *const [i32]
-| 10: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:18:5: 18:18, inferred_ty: *const [i32; 10]
-| 11: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:20:5: 20:25, inferred_ty: *const dyn std::marker::Send
-| 12: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:23:12: 23:20, inferred_ty: *const [i32; 10]
-| 13: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*const ^0) }, span: $DIR/address_of.rs:23:12: 23:20, inferred_ty: *const [i32; 10]
-| 14: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32; 10]) }, span: $DIR/address_of.rs:24:12: 24:28, inferred_ty: *const [i32; 10]
-| 15: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32; 10]) }, span: $DIR/address_of.rs:24:12: 24:28, inferred_ty: *const [i32; 10]
-| 16: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:25:12: 25:27, inferred_ty: *const dyn std::marker::Send
-| 17: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*const dyn std::marker::Send) }, span: $DIR/address_of.rs:25:12: 25:27, inferred_ty: *const dyn std::marker::Send
-| 18: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32]) }, span: $DIR/address_of.rs:26:12: 26:24, inferred_ty: *const [i32]
-| 19: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*const [i32]) }, span: $DIR/address_of.rs:26:12: 26:24, inferred_ty: *const [i32]
-| 20: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*mut ^0) }, span: $DIR/address_of.rs:28:5: 28:16, inferred_ty: *mut [i32; 10]
-| 21: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*mut dyn std::marker::Send) }, span: $DIR/address_of.rs:30:5: 30:23, inferred_ty: *mut dyn std::marker::Send
-| 22: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*mut ^0) }, span: $DIR/address_of.rs:33:12: 33:18, inferred_ty: *mut [i32; 10]
-| 23: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }], value: Ty(*mut ^0) }, span: $DIR/address_of.rs:33:12: 33:18, inferred_ty: *mut [i32; 10]
-| 24: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*mut [i32; 10]) }, span: $DIR/address_of.rs:34:12: 34:26, inferred_ty: *mut [i32; 10]
-| 25: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*mut [i32; 10]) }, span: $DIR/address_of.rs:34:12: 34:26, inferred_ty: *mut [i32; 10]
-| 26: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*mut dyn std::marker::Send) }, span: $DIR/address_of.rs:35:12: 35:25, inferred_ty: *mut dyn std::marker::Send
-| 27: user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: Ty(*mut dyn std::marker::Send) }, span: $DIR/address_of.rs:35:12: 35:25, inferred_ty: *mut dyn std::marker::Send
-| 28: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*mut [i32]) }, span: $DIR/address_of.rs:36:12: 36:22, inferred_ty: *mut [i32]
-| 29: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(*mut [i32]) }, span: $DIR/address_of.rs:36:12: 36:22, inferred_ty: *mut [i32]
+| 0: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:7:5: 7:18, inferred_ty: *const [i32; 10]
+| 1: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:9:5: 9:25, inferred_ty: *const dyn std::marker::Send
+| 2: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:13:12: 13:20, inferred_ty: *const [i32; 10]
+| 3: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:13:12: 13:20, inferred_ty: *const [i32; 10]
+| 4: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:14:12: 14:28, inferred_ty: *const [i32; 10]
+| 5: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:14:12: 14:28, inferred_ty: *const [i32; 10]
+| 6: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:15:12: 15:27, inferred_ty: *const dyn std::marker::Send
+| 7: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:15:12: 15:27, inferred_ty: *const dyn std::marker::Send
+| 8: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:16:12: 16:24, inferred_ty: *const [i32]
+| 9: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:16:12: 16:24, inferred_ty: *const [i32]
+| 10: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:18:5: 18:18, inferred_ty: *const [i32; 10]
+| 11: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:20:5: 20:25, inferred_ty: *const dyn std::marker::Send
+| 12: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:23:12: 23:20, inferred_ty: *const [i32; 10]
+| 13: user_ty: Canonical { value: Ty(*const ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:23:12: 23:20, inferred_ty: *const [i32; 10]
+| 14: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:24:12: 24:28, inferred_ty: *const [i32; 10]
+| 15: user_ty: Canonical { value: Ty(*const [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:24:12: 24:28, inferred_ty: *const [i32; 10]
+| 16: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:25:12: 25:27, inferred_ty: *const dyn std::marker::Send
+| 17: user_ty: Canonical { value: Ty(*const dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:25:12: 25:27, inferred_ty: *const dyn std::marker::Send
+| 18: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:26:12: 26:24, inferred_ty: *const [i32]
+| 19: user_ty: Canonical { value: Ty(*const [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:26:12: 26:24, inferred_ty: *const [i32]
+| 20: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:28:5: 28:16, inferred_ty: *mut [i32; 10]
+| 21: user_ty: Canonical { value: Ty(*mut dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:30:5: 30:23, inferred_ty: *mut dyn std::marker::Send
+| 22: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:33:12: 33:18, inferred_ty: *mut [i32; 10]
+| 23: user_ty: Canonical { value: Ty(*mut ^0), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/address_of.rs:33:12: 33:18, inferred_ty: *mut [i32; 10]
+| 24: user_ty: Canonical { value: Ty(*mut [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:34:12: 34:26, inferred_ty: *mut [i32; 10]
+| 25: user_ty: Canonical { value: Ty(*mut [i32; 10]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:34:12: 34:26, inferred_ty: *mut [i32; 10]
+| 26: user_ty: Canonical { value: Ty(*mut dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:35:12: 35:25, inferred_ty: *mut dyn std::marker::Send
+| 27: user_ty: Canonical { value: Ty(*mut dyn std::marker::Send), max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }] }, span: $DIR/address_of.rs:35:12: 35:25, inferred_ty: *mut dyn std::marker::Send
+| 28: user_ty: Canonical { value: Ty(*mut [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:36:12: 36:22, inferred_ty: *mut [i32]
+| 29: user_ty: Canonical { value: Ty(*mut [i32]), max_universe: U0, variables: [] }, span: $DIR/address_of.rs:36:12: 36:22, inferred_ty: *mut [i32]
 |
 fn address_of_reborrow() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/address_of.rs:+0:26: +0:26

tests/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir

@@ -1,8 +1,8 @@
 // MIR for `main` after SimplifyCfg-initial
 
 | User Type Annotations
-| 0: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:20:17: 20:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
-| 1: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:20:17: 20:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
+| 0: user_ty: Canonical { value: Ty(std::option::Option<std::boxed::Box<u32>>), max_universe: U0, variables: [] }, span: $DIR/basic_assignment.rs:20:17: 20:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
+| 1: user_ty: Canonical { value: Ty(std::option::Option<std::boxed::Box<u32>>), max_universe: U0, variables: [] }, span: $DIR/basic_assignment.rs:20:17: 20:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/basic_assignment.rs:+0:11: +0:11