Revert "Replace DefineOpaqueTypes::No => DefineOpaqueTypes::Yes"

chansuke · chansuke · commit efb14703b341 · 2023-11-03T15:32:01.000+09:00
This reverts commit 5f842a7.
diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
@@ -165,7 +165,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
     use rustc_type_ir::TyKind::*;
     match (source.kind(), target.kind()) {
         (&Ref(r_a, _, mutbl_a), Ref(r_b, _, mutbl_b))
-            if infcx.at(&cause, param_env).eq(DefineOpaqueTypes::Yes, r_a, *r_b).is_ok()
+            if infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, r_a, *r_b).is_ok()
                 && mutbl_a == *mutbl_b => {}
         (&RawPtr(tm_a), &RawPtr(tm_b)) if tm_a.mutbl == tm_b.mutbl => (),
         (&Adt(def_a, args_a), &Adt(def_b, args_b)) if def_a.is_struct() && def_b.is_struct() => {
@@ -204,7 +204,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
                     }
 
                     if let Ok(ok) =
-                        infcx.at(&cause, param_env).eq(DefineOpaqueTypes::Yes, ty_a, ty_b)
+                        infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, ty_a, ty_b)
                     {
                         if ok.obligations.is_empty() {
                             tcx.sess.emit_err(errors::DispatchFromDynZST {
@@ -406,7 +406,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
                     // we may have to evaluate constraint
                     // expressions in the course of execution.)
                     // See e.g., #41936.
-                    if let Ok(ok) = infcx.at(&cause, param_env).eq(DefineOpaqueTypes::Yes, a, b) {
+                    if let Ok(ok) = infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, a, b) {
                         if ok.obligations.is_empty() {
                             return None;
                         }
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
@@ -799,7 +799,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let param = callee_args.const_at(host_effect_index);
         let cause = self.misc(span);
-        match self.at(&cause, self.param_env).eq(infer::DefineOpaqueTypes::Yes, effect, param) {
+        match self.at(&cause, self.param_env).eq(infer::DefineOpaqueTypes::No, effect, param) {
             Ok(infer::InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
             }
diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs
@@ -1140,7 +1140,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // are the same function and their parameters have a LUB.
                         match self.commit_if_ok(|_| {
                             self.at(cause, self.param_env).lub(
-                                DefineOpaqueTypes::Yes,
+                                DefineOpaqueTypes::No,
                                 prev_ty,
                                 new_ty,
                             )
@@ -1194,7 +1194,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let sig = self
                 .at(cause, self.param_env)
                 .trace(prev_ty, new_ty)
-                .lub(DefineOpaqueTypes::Yes, a_sig, b_sig)
+                .lub(DefineOpaqueTypes::No, a_sig, b_sig)
                 .map(|ok| self.register_infer_ok_obligations(ok))?;
 
             // Reify both sides and return the reified fn pointer type.
@@ -1283,7 +1283,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                 return self
                     .commit_if_ok(|_| {
-                        self.at(cause, self.param_env).lub(DefineOpaqueTypes::Yes, prev_ty, new_ty)
+                        self.at(cause, self.param_env).lub(DefineOpaqueTypes::No, prev_ty, new_ty)
                     })
                     .map(|ok| self.register_infer_ok_obligations(ok));
             }
@@ -1296,7 +1296,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     Err(e)
                 } else {
                     self.commit_if_ok(|_| {
-                        self.at(cause, self.param_env).lub(DefineOpaqueTypes::Yes, prev_ty, new_ty)
+                        self.at(cause, self.param_env).lub(DefineOpaqueTypes::No, prev_ty, new_ty)
                     })
                     .map(|ok| self.register_infer_ok_obligations(ok))
                 }
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs
@@ -391,7 +391,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // what our ideal rcvr ty would look like.
                     let _ = self
                         .at(&ObligationCause::dummy(), self.param_env)
-                        .eq(DefineOpaqueTypes::Yes, method.sig.inputs()[idx + 1], arg_ty)
+                        .eq(DefineOpaqueTypes::No, method.sig.inputs()[idx + 1], arg_ty)
                         .ok()?;
                     self.select_obligations_where_possible(|errs| {
                         // Yeet the errors, we're already reporting errors.
@@ -470,7 +470,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .and_then(|method| {
                         let _ = self
                             .at(&ObligationCause::dummy(), self.param_env)
-                            .eq(DefineOpaqueTypes::Yes, ideal_rcvr_ty, expected_ty)
+                            .eq(DefineOpaqueTypes::No, ideal_rcvr_ty, expected_ty)
                             .ok()?;
                         Some(method)
                     });
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1751,7 +1751,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 let target_ty = self.field_ty(base_expr.span, f, args);
                                 let cause = self.misc(base_expr.span);
                                 match self.at(&cause, self.param_env).sup(
-                                    DefineOpaqueTypes::Yes,
+                                    DefineOpaqueTypes::No,
                                     target_ty,
                                     fru_ty,
                                 ) {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -542,7 +542,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let span = self.tcx.hir().body(body_id).value.span;
             let ok = self
                 .at(&self.misc(span), self.param_env)
-                .eq(DefineOpaqueTypes::Yes, interior, witness)
+                .eq(DefineOpaqueTypes::No, interior, witness)
                 .expect("Failed to unify coroutine interior type");
             let mut obligations = ok.obligations;
 
@@ -1423,7 +1423,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let impl_ty = self.normalize(span, tcx.type_of(impl_def_id).instantiate(tcx, args));
             let self_ty = self.normalize(span, self_ty);
             match self.at(&self.misc(span), self.param_env).eq(
-                DefineOpaqueTypes::Yes,
+                DefineOpaqueTypes::No,
                 impl_ty,
                 self_ty,
             ) {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -301,7 +301,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // 3. Check if the formal type is a supertype of the checked one
             //    and register any such obligations for future type checks
             let supertype_error = self.at(&self.misc(provided_arg.span), self.param_env).sup(
-                DefineOpaqueTypes::Yes,
+                DefineOpaqueTypes::No,
                 formal_input_ty,
                 coerced_ty,
             );
@@ -596,7 +596,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Using probe here, since we don't want this subtyping to affect inference.
             let subtyping_error = self.probe(|_| {
                 self.at(&self.misc(arg_span), self.param_env)
-                    .sup(DefineOpaqueTypes::Yes, formal_input_ty, coerced_ty)
+                    .sup(DefineOpaqueTypes::No, formal_input_ty, coerced_ty)
                     .err()
             });
 
diff --git a/compiler/rustc_hir_typeck/src/method/confirm.rs b/compiler/rustc_hir_typeck/src/method/confirm.rs
@@ -502,7 +502,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                 args,
             })),
         );
-        match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::Yes, method_self_ty, self_ty) {
+        match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::No, method_self_ty, self_ty) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
             }
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -935,7 +935,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 if let Some(self_ty) = self_ty {
                     if self
                         .at(&ObligationCause::dummy(), self.param_env)
-                        .sup(DefineOpaqueTypes::Yes, fty.inputs()[0], self_ty)
+                        .sup(DefineOpaqueTypes::No, fty.inputs()[0], self_ty)
                         .is_err()
                     {
                         return false;
@@ -1454,7 +1454,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             }
             TraitCandidate(trait_ref) => self.probe(|_| {
                 let _ = self.at(&ObligationCause::dummy(), self.param_env).sup(
-                    DefineOpaqueTypes::Yes,
+                    DefineOpaqueTypes::No,
                     candidate.xform_self_ty,
                     self_ty,
                 );
@@ -1485,10 +1485,6 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         self.probe(|_| {
             // First check that the self type can be related.
             let sub_obligations = match self.at(&ObligationCause::dummy(), self.param_env).sup(
-                // https://github.com/rust-lang/rust/issues/116652
-                // Failed tests:
-                // tests/ui/impl-trait/issues/issue-70877.rs
-                // tests/ui/type-alias-impl-trait/type-alias-impl-trait.rs
                 DefineOpaqueTypes::No,
                 probe.xform_self_ty,
                 self_ty,
@@ -1697,7 +1693,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 if let ProbeResult::Match = result
                     && self
                         .at(&ObligationCause::dummy(), self.param_env)
-                        .sup(DefineOpaqueTypes::Yes, return_ty, xform_ret_ty)
+                        .sup(DefineOpaqueTypes::No, return_ty, xform_ret_ty)
                         .is_err()
                 {
                     result = ProbeResult::BadReturnType;
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
@@ -908,15 +908,15 @@ impl<'tcx> InferCtxt<'tcx> {
         T: at::ToTrace<'tcx>,
     {
         let origin = &ObligationCause::dummy();
-        self.probe(|_| self.at(origin, param_env).sub(DefineOpaqueTypes::Yes, a, b).is_ok())
+        self.probe(|_| self.at(origin, param_env).sub(DefineOpaqueTypes::No, a, b).is_ok())
     }
 
     pub fn can_eq<T>(&self, param_env: ty::ParamEnv<'tcx>, a: T, b: T) -> bool
     where
         T: at::ToTrace<'tcx>,
     {
         let origin = &ObligationCause::dummy();
-        self.probe(|_| self.at(origin, param_env).eq(DefineOpaqueTypes::Yes, a, b).is_ok())
+        self.probe(|_| self.at(origin, param_env).eq(DefineOpaqueTypes::No, a, b).is_ok())
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -1012,7 +1012,7 @@ impl<'tcx> InferCtxt<'tcx> {
                 self.instantiate_binder_with_placeholders(predicate);
 
             let ok =
-                self.at(cause, param_env).sub_exp(DefineOpaqueTypes::Yes, a_is_expected, a, b)?;
+                self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b)?;
 
             Ok(ok.unit())
         }))
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
@@ -323,7 +323,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             nested_goals.extend(
                 infcx
                     .at(&ObligationCause::dummy(), param_env)
-                    .eq(DefineOpaqueTypes::Yes, orig, response)
+                    .eq(DefineOpaqueTypes::No, orig, response)
                     .map(|InferOk { value: (), obligations }| {
                         obligations.into_iter().map(|o| Goal::from(o))
                     })
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
@@ -721,7 +721,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ) -> Result<(), NoSolution> {
         self.infcx
             .at(&ObligationCause::dummy(), param_env)
-            .eq(DefineOpaqueTypes::Yes, lhs, rhs)
+            .eq(DefineOpaqueTypes::No, lhs, rhs)
             .map(|InferOk { value: (), obligations }| {
                 self.add_goals(obligations.into_iter().map(|o| o.into()));
             })
@@ -740,7 +740,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ) -> Result<(), NoSolution> {
         self.infcx
             .at(&ObligationCause::dummy(), param_env)
-            .sub(DefineOpaqueTypes::Yes, sub, sup)
+            .sub(DefineOpaqueTypes::No, sub, sup)
             .map(|InferOk { value: (), obligations }| {
                 self.add_goals(obligations.into_iter().map(|o| o.into()));
             })
@@ -764,7 +764,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
     ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
         self.infcx
             .at(&ObligationCause::dummy(), param_env)
-            .eq(DefineOpaqueTypes::Yes, lhs, rhs)
+            .eq(DefineOpaqueTypes::No, lhs, rhs)
             .map(|InferOk { value: (), obligations }| {
                 obligations.into_iter().map(|o| o.into()).collect()
             })
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
@@ -202,7 +202,7 @@ fn rematch_impl<'tcx>(
     nested.extend(
         infcx
             .at(&ObligationCause::dummy(), goal.param_env)
-            .eq(DefineOpaqueTypes::Yes, goal.predicate.trait_ref, impl_trait_ref)
+            .eq(DefineOpaqueTypes::No, goal.predicate.trait_ref, impl_trait_ref)
             .map_err(|_| SelectionError::Unimplemented)?
             .into_obligations(),
     );
@@ -278,7 +278,7 @@ fn rematch_unsize<'tcx>(
             nested.extend(
                 infcx
                     .at(&ObligationCause::dummy(), goal.param_env)
-                    .eq(DefineOpaqueTypes::Yes, a_elem_ty, b_elem_ty)
+                    .eq(DefineOpaqueTypes::No, a_elem_ty, b_elem_ty)
                     .expect("expected rematch to succeed")
                     .into_obligations(),
             );
@@ -321,7 +321,7 @@ fn rematch_unsize<'tcx>(
             nested.extend(
                 infcx
                     .at(&ObligationCause::dummy(), goal.param_env)
-                    .eq(DefineOpaqueTypes::Yes, unsized_a_ty, b_ty)
+                    .eq(DefineOpaqueTypes::No, unsized_a_ty, b_ty)
                     .expect("expected rematch to succeed")
                     .into_obligations(),
             );
@@ -350,7 +350,7 @@ fn rematch_unsize<'tcx>(
             nested.extend(
                 infcx
                     .at(&ObligationCause::dummy(), goal.param_env)
-                    .eq(DefineOpaqueTypes::Yes, unsized_a_ty, b_ty)
+                    .eq(DefineOpaqueTypes::No, unsized_a_ty, b_ty)
                     .expect("expected rematch to succeed")
                     .into_obligations(),
             );
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -804,7 +804,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
 
                     match (evaluate(c1), evaluate(c2)) {
                         (Ok(c1), Ok(c2)) => {
-                            match selcx.infcx.at(&obligation.cause, obligation.param_env).eq(DefineOpaqueTypes::Yes,c1, c2)
+                            match selcx.infcx.at(&obligation.cause, obligation.param_env).eq(DefineOpaqueTypes::No,c1, c2)
                             {
                                 Ok(_) => (),
                                 Err(_) => return false,
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -3592,7 +3592,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     for (expected, actual) in zipped {
                         self.probe(|_| {
                             match self.at(&ObligationCause::misc(expr.span, body_id), param_env).eq(
-                                DefineOpaqueTypes::Yes,
+                                DefineOpaqueTypes::No,
                                 expected,
                                 actual,
                             ) {
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -537,7 +537,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 if let Ok(new_obligations) = infcx
                                     .at(&obligation.cause, obligation.param_env)
                                     .trace(c1, c2)
-                                    .eq(DefineOpaqueTypes::Yes, a.args, b.args)
+                                    .eq(DefineOpaqueTypes::No, a.args, b.args)
                                 {
                                     return ProcessResult::Changed(mk_pending(
                                         new_obligations.into_obligations(),
@@ -548,7 +548,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                             (_, _) => {
                                 if let Ok(new_obligations) = infcx
                                     .at(&obligation.cause, obligation.param_env)
-                                    .eq(DefineOpaqueTypes::Yes, c1, c2)
+                                    .eq(DefineOpaqueTypes::No, c1, c2)
                                 {
                                     return ProcessResult::Changed(mk_pending(
                                         new_obligations.into_obligations(),
@@ -589,7 +589,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     match (evaluate(c1), evaluate(c2)) {
                         (Ok(c1), Ok(c2)) => {
                             match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq(
-                                DefineOpaqueTypes::Yes,
+                                DefineOpaqueTypes::No,
                                 c1,
                                 c2,
                             ) {
@@ -631,7 +631,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 }
                 ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
                     match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq(
-                        DefineOpaqueTypes::Yes,
+                        DefineOpaqueTypes::No,
                         ct.ty(),
                         ty,
                     ) {
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -1441,7 +1441,7 @@ pub fn compute_inherent_assoc_ty_args<'a, 'b, 'tcx>(
     // Infer the generic parameters of the impl by unifying the
     // impl type with the self type of the projection.
     let self_ty = alias_ty.self_ty();
-    match selcx.infcx.at(&cause, param_env).eq(DefineOpaqueTypes::Yes, impl_ty, self_ty) {
+    match selcx.infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, impl_ty, self_ty) {
         Ok(mut ok) => obligations.append(&mut ok.obligations),
         Err(_) => {
             tcx.sess.delay_span_bug(
@@ -2354,7 +2354,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
     debug!(?cache_projection, ?obligation_projection);
 
     match infcx.at(cause, param_env).eq(
-        DefineOpaqueTypes::Yes,
+        DefineOpaqueTypes::No,
         cache_projection,
         obligation_projection,
     ) {
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs

Original file line number	Diff line number	Diff line change
`@@ -799,7 +799,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {`
`799`	`799`
`800`	`800`	`let param = callee_args.const_at(host_effect_index);`
`801`	`801`	`let cause = self.misc(span);`
`802`		`- match self.at(&cause, self.param_env).eq(infer::DefineOpaqueTypes::Yes, effect, param) {`
	`802`	`+ match self.at(&cause, self.param_env).eq(infer::DefineOpaqueTypes::No, effect, param) {`
`803`	`803`	`Ok(infer::InferOk { obligations, value: () }) => {`
`804`	`804`	`self.register_predicates(obligations);`
`805`	`805`	`}`
Original file line number	Diff line number	Diff line change
`@@ -502,7 +502,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {`
`502`	`502`	`args,`
`503`	`503`	`})),`
`504`	`504`	`);`
`505`		`- match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::Yes, method_self_ty, self_ty) {`
	`505`	`+ match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::No, method_self_ty, self_ty) {`
`506`	`506`	`Ok(InferOk { obligations, value: () }) => {`
`507`	`507`	`self.register_predicates(obligations);`
`508`	`508`	`}`
Original file line number	Diff line number	Diff line change
`@@ -908,15 +908,15 @@ impl<'tcx> InferCtxt<'tcx> {`
`908`	`908`	`T: at::ToTrace<'tcx>,`
`909`	`909`	`{`
`910`	`910`	`let origin = &ObligationCause::dummy();`
`911`		`- self.probe(\|_\| self.at(origin, param_env).sub(DefineOpaqueTypes::Yes, a, b).is_ok())`
	`911`	`+ self.probe(\|_\| self.at(origin, param_env).sub(DefineOpaqueTypes::No, a, b).is_ok())`
`912`	`912`	`}`
`913`	`913`
`914`	`914`	`pub fn can_eq<T>(&self, param_env: ty::ParamEnv<'tcx>, a: T, b: T) -> bool`
`915`	`915`	`where`
`916`	`916`	`T: at::ToTrace<'tcx>,`
`917`	`917`	`{`
`918`	`918`	`let origin = &ObligationCause::dummy();`
`919`		`- self.probe(\|_\| self.at(origin, param_env).eq(DefineOpaqueTypes::Yes, a, b).is_ok())`
	`919`	`+ self.probe(\|_\| self.at(origin, param_env).eq(DefineOpaqueTypes::No, a, b).is_ok())`
`920`	`920`	`}`
`921`	`921`
`922`	`922`	`#[instrument(skip(self), level = "debug")]`
`@@ -1012,7 +1012,7 @@ impl<'tcx> InferCtxt<'tcx> {`
`1012`	`1012`	`self.instantiate_binder_with_placeholders(predicate);`
`1013`	`1013`
`1014`	`1014`	`let ok =`
`1015`		`- self.at(cause, param_env).sub_exp(DefineOpaqueTypes::Yes, a_is_expected, a, b)?;`
	`1015`	`+ self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b)?;`
`1016`	`1016`
`1017`	`1017`	`Ok(ok.unit())`
`1018`	`1018`	`}))`