From d294e4746bb1dae054b8e3e195b96e644e271b04 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Sat, 23 Nov 2024 04:46:53 +0000
Subject: [PATCH] Remove unnecessary bool from ExpectedFound

---
 .../rustc_hir_typeck/src/fn_ctxt/checks.rs    |  4 +-
 compiler/rustc_infer/src/infer/at.rs          | 42 ++++++-------------
 compiler/rustc_infer/src/infer/mod.rs         | 18 ++------
 .../rustc_infer/src/infer/opaque_types/mod.rs |  2 +-
 compiler/rustc_middle/src/ty/relate.rs        |  4 +-
 .../src/error_reporting/infer/mod.rs          |  4 +-
 .../traits/fulfillment_errors.rs              |  7 ++--
 .../src/solve/fulfill.rs                      |  4 +-
 .../src/traits/fulfill.rs                     | 13 +++---
 .../src/traits/select/_match.rs               |  4 +-
 compiler/rustc_type_ir/src/error.rs           |  8 +---
 compiler/rustc_type_ir/src/relate.rs          | 34 +++++++--------
 compiler/rustc_type_ir/src/relate/combine.rs  |  4 +-
 13 files changed, 58 insertions(+), 90 deletions(-)

diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 961526831fbfd..9c18dbd422d90 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -729,7 +729,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let can_coerce = self.may_coerce(arg_ty, coerced_ty);
             if !can_coerce {
                 return Compatibility::Incompatible(Some(ty::error::TypeError::Sorts(
-                    ty::error::ExpectedFound::new(true, coerced_ty, arg_ty),
+                    ty::error::ExpectedFound::new(coerced_ty, arg_ty),
                 )));
             }
 
@@ -758,7 +758,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             } else {
                 expected_ty
             };
-            TypeTrace::types(&self.misc(span), true, mismatched_ty, provided_ty)
+            TypeTrace::types(&self.misc(span), mismatched_ty, provided_ty)
         };
 
         // The algorithm here is inspired by levenshtein distance and longest common subsequence.
diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs
index 3eda3e9c67e85..12e2bbc968f0f 100644
--- a/compiler/rustc_infer/src/infer/at.rs
+++ b/compiler/rustc_infer/src/infer/at.rs
@@ -308,17 +308,14 @@ impl<'tcx> ToTrace<'tcx> for Ty<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::Region<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::Regions(ExpectedFound::new(true, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::Regions(ExpectedFound::new(a, b)) }
     }
 }
 
@@ -326,7 +323,7 @@ impl<'tcx> ToTrace<'tcx> for Const<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())),
         }
     }
 }
@@ -337,13 +334,13 @@ impl<'tcx> ToTrace<'tcx> for ty::GenericArg<'tcx> {
             cause: cause.clone(),
             values: match (a.unpack(), b.unpack()) {
                 (GenericArgKind::Lifetime(a), GenericArgKind::Lifetime(b)) => {
-                    ValuePairs::Regions(ExpectedFound::new(true, a, b))
+                    ValuePairs::Regions(ExpectedFound::new(a, b))
                 }
                 (GenericArgKind::Type(a), GenericArgKind::Type(b)) => {
-                    ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into()))
+                    ValuePairs::Terms(ExpectedFound::new(a.into(), b.into()))
                 }
                 (GenericArgKind::Const(a), GenericArgKind::Const(b)) => {
-                    ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into()))
+                    ValuePairs::Terms(ExpectedFound::new(a.into(), b.into()))
                 }
                 _ => bug!("relating different kinds: {a:?} {b:?}"),
             },
@@ -353,19 +350,13 @@ impl<'tcx> ToTrace<'tcx> for ty::GenericArg<'tcx> {
 
 impl<'tcx> ToTrace<'tcx> for ty::Term<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(true, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::Terms(ExpectedFound::new(a, b)) }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::TraitRef<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::TraitRefs(ExpectedFound::new(true, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::TraitRefs(ExpectedFound::new(a, b)) }
     }
 }
 
@@ -373,17 +364,14 @@ impl<'tcx> ToTrace<'tcx> for ty::AliasTy<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Aliases(ExpectedFound::new(true, a.into(), b.into())),
+            values: ValuePairs::Aliases(ExpectedFound::new(a.into(), b.into())),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::AliasTerm<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::Aliases(ExpectedFound::new(true, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::Aliases(ExpectedFound::new(a, b)) }
     }
 }
 
@@ -392,7 +380,6 @@ impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
         TypeTrace {
             cause: cause.clone(),
             values: ValuePairs::PolySigs(ExpectedFound::new(
-                true,
                 ty::Binder::dummy(a),
                 ty::Binder::dummy(b),
             )),
@@ -402,10 +389,7 @@ impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
 
 impl<'tcx> ToTrace<'tcx> for ty::PolyFnSig<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::PolySigs(ExpectedFound::new(true, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::PolySigs(ExpectedFound::new(a, b)) }
     }
 }
 
@@ -413,7 +397,7 @@ impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialTraitRef<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::ExistentialTraitRef(ExpectedFound::new(true, a, b)),
+            values: ValuePairs::ExistentialTraitRef(ExpectedFound::new(a, b)),
         }
     }
 }
@@ -422,7 +406,7 @@ impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialProjection<'tcx> {
     fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::ExistentialProjection(ExpectedFound::new(true, a, b)),
+            values: ValuePairs::ExistentialProjection(ExpectedFound::new(a, b)),
         }
     }
 }
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index b29dc7f909dd5..7345c388c4f20 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -1478,39 +1478,29 @@ impl<'tcx> TypeTrace<'tcx> {
         self.cause.span
     }
 
-    pub fn types(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Ty<'tcx>,
-        b: Ty<'tcx>,
-    ) -> TypeTrace<'tcx> {
+    pub fn types(cause: &ObligationCause<'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())),
         }
     }
 
     pub fn trait_refs(
         cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
         a: ty::TraitRef<'tcx>,
         b: ty::TraitRef<'tcx>,
     ) -> TypeTrace<'tcx> {
-        TypeTrace {
-            cause: cause.clone(),
-            values: ValuePairs::TraitRefs(ExpectedFound::new(a_is_expected, a, b)),
-        }
+        TypeTrace { cause: cause.clone(), values: ValuePairs::TraitRefs(ExpectedFound::new(a, b)) }
     }
 
     pub fn consts(
         cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
         a: ty::Const<'tcx>,
         b: ty::Const<'tcx>,
     ) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())),
         }
     }
 }
diff --git a/compiler/rustc_infer/src/infer/opaque_types/mod.rs b/compiler/rustc_infer/src/infer/opaque_types/mod.rs
index 0aff46203144a..5499fed1bdfd6 100644
--- a/compiler/rustc_infer/src/infer/opaque_types/mod.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types/mod.rs
@@ -177,7 +177,7 @@ impl<'tcx> InferCtxt<'tcx> {
             res
         } else {
             let (a, b) = self.resolve_vars_if_possible((a, b));
-            Err(TypeError::Sorts(ExpectedFound::new(true, a, b)))
+            Err(TypeError::Sorts(ExpectedFound::new(a, b)))
         }
     }
 
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 504a3c8a6d832..b06687490d26c 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -92,7 +92,7 @@ impl<'tcx> Relate<TyCtxt<'tcx>> for &'tcx ty::List<ty::PolyExistentialPredicate<
         b_v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
         b_v.dedup();
         if a_v.len() != b_v.len() {
-            return Err(TypeError::ExistentialMismatch(ExpectedFound::new(true, a, b)));
+            return Err(TypeError::ExistentialMismatch(ExpectedFound::new(a, b)));
         }
 
         let v = iter::zip(a_v, b_v).map(|(ep_a, ep_b)| {
@@ -112,7 +112,7 @@ impl<'tcx> Relate<TyCtxt<'tcx>> for &'tcx ty::List<ty::PolyExistentialPredicate<
                     ty::ExistentialPredicate::AutoTrait(a),
                     ty::ExistentialPredicate::AutoTrait(b),
                 ) if a == b => Ok(ep_a.rebind(ty::ExistentialPredicate::AutoTrait(a))),
-                _ => Err(TypeError::ExistentialMismatch(ExpectedFound::new(true, a, b))),
+                _ => Err(TypeError::ExistentialMismatch(ExpectedFound::new(a, b))),
             }
         });
         tcx.mk_poly_existential_predicates_from_iter(v)
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
index 929fa559d750c..c7ad14ac0bfce 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
@@ -152,7 +152,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         err: TypeError<'tcx>,
     ) -> Diag<'a> {
         self.report_and_explain_type_error(
-            TypeTrace::types(cause, true, expected, actual),
+            TypeTrace::types(cause, expected, actual),
             param_env,
             err,
         )
@@ -167,7 +167,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         err: TypeError<'tcx>,
     ) -> Diag<'a> {
         self.report_and_explain_type_error(
-            TypeTrace::consts(cause, true, expected, actual),
+            TypeTrace::consts(cause, expected, actual),
             param_env,
             err,
         )
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 4e7d7b79ff4de..107ebe8adf03c 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -725,7 +725,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     &obligation.cause,
                     None,
                     None,
-                    TypeError::Sorts(ty::error::ExpectedFound::new(true, expected_ty, ct_ty)),
+                    TypeError::Sorts(ty::error::ExpectedFound::new(expected_ty, ct_ty)),
                     false,
                 );
                 diag
@@ -1449,7 +1449,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 secondary_span,
                 values.map(|(_, normalized_ty, expected_ty)| {
                     obligation.param_env.and(infer::ValuePairs::Terms(ExpectedFound::new(
-                        true,
                         expected_ty,
                         normalized_ty,
                     )))
@@ -2755,7 +2754,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             (obligation.cause.clone(), terr)
         };
         self.report_and_explain_type_error(
-            TypeTrace::trait_refs(&cause, true, expected_trait_ref, found_trait_ref),
+            TypeTrace::trait_refs(&cause, expected_trait_ref, found_trait_ref),
             obligation.param_env,
             terr,
         )
@@ -2846,7 +2845,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         if Some(expected_trait_ref.def_id) != self.tcx.lang_items().coroutine_trait() && not_tupled
         {
             return Ok(self.report_and_explain_type_error(
-                TypeTrace::trait_refs(&obligation.cause, true, expected_trait_ref, found_trait_ref),
+                TypeTrace::trait_refs(&obligation.cause, expected_trait_ref, found_trait_ref),
                 obligation.param_env,
                 ty::error::TypeError::Mismatch,
             ));
diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs
index 53e5420d27a5d..311dc214de601 100644
--- a/compiler/rustc_trait_selection/src/solve/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs
@@ -264,14 +264,14 @@ fn fulfillment_error_for_no_solution<'tcx>(
             let (a, b) = infcx.enter_forall_and_leak_universe(
                 obligation.predicate.kind().rebind((pred.a, pred.b)),
             );
-            let expected_found = ExpectedFound::new(true, a, b);
+            let expected_found = ExpectedFound::new(a, b);
             FulfillmentErrorCode::Subtype(expected_found, TypeError::Sorts(expected_found))
         }
         ty::PredicateKind::Coerce(pred) => {
             let (a, b) = infcx.enter_forall_and_leak_universe(
                 obligation.predicate.kind().rebind((pred.a, pred.b)),
             );
-            let expected_found = ExpectedFound::new(false, a, b);
+            let expected_found = ExpectedFound::new(b, a);
             FulfillmentErrorCode::Subtype(expected_found, TypeError::Sorts(expected_found))
         }
         ty::PredicateKind::Clause(_)
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index 2ec5f0d22496d..581f0c5c7bad2 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -557,8 +557,11 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                             ProcessResult::Changed(mk_pending(ok.obligations))
                         }
                         Ok(Err(err)) => {
-                            let expected_found =
-                                ExpectedFound::new(subtype.a_is_expected, subtype.a, subtype.b);
+                            let expected_found = if subtype.a_is_expected {
+                                ExpectedFound::new(subtype.a, subtype.b)
+                            } else {
+                                ExpectedFound::new(subtype.b, subtype.a)
+                            };
                             ProcessResult::Error(FulfillmentErrorCode::Subtype(expected_found, err))
                         }
                     }
@@ -578,7 +581,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                         }
                         Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
                         Ok(Err(err)) => {
-                            let expected_found = ExpectedFound::new(false, coerce.a, coerce.b);
+                            let expected_found = ExpectedFound::new(coerce.b, coerce.a);
                             ProcessResult::Error(FulfillmentErrorCode::Subtype(expected_found, err))
                         }
                     }
@@ -703,7 +706,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 }
                                 Err(err) => {
                                     ProcessResult::Error(FulfillmentErrorCode::ConstEquate(
-                                        ExpectedFound::new(true, c1, c2),
+                                        ExpectedFound::new(c1, c2),
                                         err,
                                     ))
                                 }
@@ -727,7 +730,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 ProcessResult::Unchanged
                             } else {
                                 // Two different constants using generic parameters ~> error.
-                                let expected_found = ExpectedFound::new(true, c1, c2);
+                                let expected_found = ExpectedFound::new(c1, c2);
                                 ProcessResult::Error(FulfillmentErrorCode::ConstEquate(
                                     expected_found,
                                     TypeError::ConstMismatch(expected_found),
diff --git a/compiler/rustc_trait_selection/src/traits/select/_match.rs b/compiler/rustc_trait_selection/src/traits/select/_match.rs
index 3980d672a11bc..7c19c35a4f784 100644
--- a/compiler/rustc_trait_selection/src/traits/select/_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/_match.rs
@@ -70,7 +70,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
             ) => Ok(a),
 
             (&ty::Infer(_), _) | (_, &ty::Infer(_)) => {
-                Err(TypeError::Sorts(ExpectedFound::new(true, a, b)))
+                Err(TypeError::Sorts(ExpectedFound::new(a, b)))
             }
 
             (&ty::Error(guar), _) | (_, &ty::Error(guar)) => Ok(Ty::new_error(self.cx(), guar)),
@@ -95,7 +95,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
             }
 
             (ty::ConstKind::Infer(_), _) | (_, ty::ConstKind::Infer(_)) => {
-                return Err(TypeError::ConstMismatch(ExpectedFound::new(true, a, b)));
+                return Err(TypeError::ConstMismatch(ExpectedFound::new(a, b)));
             }
 
             _ => {}
diff --git a/compiler/rustc_type_ir/src/error.rs b/compiler/rustc_type_ir/src/error.rs
index cdff77f742d0a..59dea7695111f 100644
--- a/compiler/rustc_type_ir/src/error.rs
+++ b/compiler/rustc_type_ir/src/error.rs
@@ -12,12 +12,8 @@ pub struct ExpectedFound<T> {
 }
 
 impl<T> ExpectedFound<T> {
-    pub fn new(a_is_expected: bool, a: T, b: T) -> Self {
-        if a_is_expected {
-            ExpectedFound { expected: a, found: b }
-        } else {
-            ExpectedFound { expected: b, found: a }
-        }
+    pub fn new(expected: T, found: T) -> Self {
+        ExpectedFound { expected, found }
     }
 }
 
diff --git a/compiler/rustc_type_ir/src/relate.rs b/compiler/rustc_type_ir/src/relate.rs
index ad17911830b3d..6b301b1606050 100644
--- a/compiler/rustc_type_ir/src/relate.rs
+++ b/compiler/rustc_type_ir/src/relate.rs
@@ -171,16 +171,16 @@ impl<I: Interner> Relate<I> for ty::FnSig<I> {
             return Err(TypeError::VariadicMismatch({
                 let a = a.c_variadic;
                 let b = b.c_variadic;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }));
         }
 
         if a.safety != b.safety {
-            return Err(TypeError::SafetyMismatch(ExpectedFound::new(true, a.safety, b.safety)));
+            return Err(TypeError::SafetyMismatch(ExpectedFound::new(a.safety, b.safety)));
         }
 
         if a.abi != b.abi {
-            return Err(TypeError::AbiMismatch(ExpectedFound::new(true, a.abi, b.abi)));
+            return Err(TypeError::AbiMismatch(ExpectedFound::new(a.abi, b.abi)));
         };
 
         let a_inputs = a.inputs();
@@ -233,7 +233,7 @@ impl<I: Interner> Relate<I> for ty::AliasTy<I> {
             Err(TypeError::ProjectionMismatched({
                 let a = a.def_id;
                 let b = b.def_id;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }))
         } else {
             let args = match a.kind(relation.cx()) {
@@ -274,7 +274,7 @@ impl<I: Interner> Relate<I> for ty::AliasTerm<I> {
             Err(TypeError::ProjectionMismatched({
                 let a = a.def_id;
                 let b = b.def_id;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }))
         } else {
             let args = match a.kind(relation.cx()) {
@@ -309,7 +309,7 @@ impl<I: Interner> Relate<I> for ty::ExistentialProjection<I> {
             Err(TypeError::ProjectionMismatched({
                 let a = a.def_id;
                 let b = b.def_id;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }))
         } else {
             let term = relation.relate_with_variance(
@@ -340,7 +340,7 @@ impl<I: Interner> Relate<I> for ty::TraitRef<I> {
             Err(TypeError::Traits({
                 let a = a.def_id;
                 let b = b.def_id;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }))
         } else {
             let args = relate_args_invariantly(relation, a.args, b.args)?;
@@ -360,7 +360,7 @@ impl<I: Interner> Relate<I> for ty::ExistentialTraitRef<I> {
             Err(TypeError::Traits({
                 let a = a.def_id;
                 let b = b.def_id;
-                ExpectedFound::new(true, a, b)
+                ExpectedFound::new(a, b)
             }))
         } else {
             let args = relate_args_invariantly(relation, a.args, b.args)?;
@@ -508,9 +508,9 @@ pub fn structurally_relate_tys<I: Interner, R: TypeRelation<I>>(
                     let sz_b = sz_b.try_to_target_usize(cx);
 
                     match (sz_a, sz_b) {
-                        (Some(sz_a_val), Some(sz_b_val)) if sz_a_val != sz_b_val => Err(
-                            TypeError::FixedArraySize(ExpectedFound::new(true, sz_a_val, sz_b_val)),
-                        ),
+                        (Some(sz_a_val), Some(sz_b_val)) if sz_a_val != sz_b_val => {
+                            Err(TypeError::FixedArraySize(ExpectedFound::new(sz_a_val, sz_b_val)))
+                        }
                         _ => Err(err),
                     }
                 }
@@ -529,9 +529,9 @@ pub fn structurally_relate_tys<I: Interner, R: TypeRelation<I>>(
                     iter::zip(as_.iter(), bs.iter()).map(|(a, b)| relation.relate(a, b)),
                 )?)
             } else if !(as_.is_empty() || bs.is_empty()) {
-                Err(TypeError::TupleSize(ExpectedFound::new(true, as_.len(), bs.len())))
+                Err(TypeError::TupleSize(ExpectedFound::new(as_.len(), bs.len())))
             } else {
-                Err(TypeError::Sorts(ExpectedFound::new(true, a, b)))
+                Err(TypeError::Sorts(ExpectedFound::new(a, b)))
             }
         }
 
@@ -558,7 +558,7 @@ pub fn structurally_relate_tys<I: Interner, R: TypeRelation<I>>(
             Ok(Ty::new_pat(cx, ty, pat))
         }
 
-        _ => Err(TypeError::Sorts(ExpectedFound::new(true, a, b))),
+        _ => Err(TypeError::Sorts(ExpectedFound::new(a, b))),
     }
 }
 
@@ -637,7 +637,7 @@ pub fn structurally_relate_consts<I: Interner, R: TypeRelation<I>>(
         }
         _ => false,
     };
-    if is_match { Ok(a) } else { Err(TypeError::ConstMismatch(ExpectedFound::new(true, a, b))) }
+    if is_match { Ok(a) } else { Err(TypeError::ConstMismatch(ExpectedFound::new(a, b))) }
 }
 
 impl<I: Interner, T: Relate<I>> Relate<I> for ty::Binder<I, T> {
@@ -658,9 +658,7 @@ impl<I: Interner> Relate<I> for ty::TraitPredicate<I> {
     ) -> RelateResult<I, ty::TraitPredicate<I>> {
         let trait_ref = relation.relate(a.trait_ref, b.trait_ref)?;
         if a.polarity != b.polarity {
-            return Err(TypeError::PolarityMismatch(ExpectedFound::new(
-                true, a.polarity, b.polarity,
-            )));
+            return Err(TypeError::PolarityMismatch(ExpectedFound::new(a.polarity, b.polarity)));
         }
         Ok(ty::TraitPredicate { trait_ref, polarity: a.polarity })
     }
diff --git a/compiler/rustc_type_ir/src/relate/combine.rs b/compiler/rustc_type_ir/src/relate/combine.rs
index 53751f7711a71..876da5d19b99a 100644
--- a/compiler/rustc_type_ir/src/relate/combine.rs
+++ b/compiler/rustc_type_ir/src/relate/combine.rs
@@ -123,9 +123,7 @@ where
         }
 
         // All other cases of inference are errors
-        (ty::Infer(_), _) | (_, ty::Infer(_)) => {
-            Err(TypeError::Sorts(ExpectedFound::new(true, a, b)))
-        }
+        (ty::Infer(_), _) | (_, ty::Infer(_)) => Err(TypeError::Sorts(ExpectedFound::new(a, b))),
 
         (ty::Alias(ty::Opaque, _), _) | (_, ty::Alias(ty::Opaque, _)) => {
             assert!(!infcx.next_trait_solver());