Rollup of 8 pull requests

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2437,7 +2437,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                                     debug!(?src_tty, ?dst_tty, ?src_obj, ?dst_obj);
 
-                                    self.eq_types(
+                                    self.sub_types(
                                         src_obj,
                                         dst_obj,
                                         location.to_locations(),

compiler/rustc_infer/src/infer/at.rs

@@ -92,12 +92,7 @@ impl<'tcx> InferCtxt<'tcx> {
 }
 
 pub trait ToTrace<'tcx>: Relate<TyCtxt<'tcx>> + Copy {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx>;
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx>;
 }
 
 impl<'a, 'tcx> At<'a, 'tcx> {
@@ -116,7 +111,7 @@ impl<'a, 'tcx> At<'a, 'tcx> {
     {
         let mut fields = CombineFields::new(
             self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
+            ToTrace::to_trace(self.cause, expected, actual),
             self.param_env,
             define_opaque_types,
         );
@@ -136,7 +131,7 @@ impl<'a, 'tcx> At<'a, 'tcx> {
     {
         let mut fields = CombineFields::new(
             self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
+            ToTrace::to_trace(self.cause, expected, actual),
             self.param_env,
             define_opaque_types,
         );
@@ -154,12 +149,26 @@ impl<'a, 'tcx> At<'a, 'tcx> {
     where
         T: ToTrace<'tcx>,
     {
-        let mut fields = CombineFields::new(
-            self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
-            self.param_env,
+        self.eq_trace(
             define_opaque_types,
-        );
+            ToTrace::to_trace(self.cause, expected, actual),
+            expected,
+            actual,
+        )
+    }
+
+    /// Makes `expected == actual`.
+    pub fn eq_trace<T>(
+        self,
+        define_opaque_types: DefineOpaqueTypes,
+        trace: TypeTrace<'tcx>,
+        expected: T,
+        actual: T,
+    ) -> InferResult<'tcx, ()>
+    where
+        T: Relate<TyCtxt<'tcx>>,
+    {
+        let mut fields = CombineFields::new(self.infcx, trace, self.param_env, define_opaque_types);
         fields.equate(StructurallyRelateAliases::No).relate(expected, actual)?;
         Ok(InferOk {
             value: (),
@@ -192,7 +201,7 @@ impl<'a, 'tcx> At<'a, 'tcx> {
         assert!(self.infcx.next_trait_solver());
         let mut fields = CombineFields::new(
             self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
+            ToTrace::to_trace(self.cause, expected, actual),
             self.param_env,
             DefineOpaqueTypes::Yes,
         );
@@ -284,7 +293,7 @@ impl<'a, 'tcx> At<'a, 'tcx> {
     {
         let mut fields = CombineFields::new(
             self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
+            ToTrace::to_trace(self.cause, expected, actual),
             self.param_env,
             define_opaque_types,
         );
@@ -306,7 +315,7 @@ impl<'a, 'tcx> At<'a, 'tcx> {
     {
         let mut fields = CombineFields::new(
             self.infcx,
-            ToTrace::to_trace(self.cause, true, expected, actual),
+            ToTrace::to_trace(self.cause, expected, actual),
             self.param_env,
             define_opaque_types,
         );
@@ -316,18 +325,13 @@ impl<'a, 'tcx> At<'a, 'tcx> {
 }
 
 impl<'tcx> ToTrace<'tcx> for ImplSubject<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         match (a, b) {
             (ImplSubject::Trait(trait_ref_a), ImplSubject::Trait(trait_ref_b)) => {
-                ToTrace::to_trace(cause, a_is_expected, trait_ref_a, trait_ref_b)
+                ToTrace::to_trace(cause, trait_ref_a, trait_ref_b)
             }
             (ImplSubject::Inherent(ty_a), ImplSubject::Inherent(ty_b)) => {
-                ToTrace::to_trace(cause, a_is_expected, ty_a, ty_b)
+                ToTrace::to_trace(cause, ty_a, ty_b)
             }
             (ImplSubject::Trait(_), ImplSubject::Inherent(_))
             | (ImplSubject::Inherent(_), ImplSubject::Trait(_)) => {
@@ -338,65 +342,45 @@ impl<'tcx> ToTrace<'tcx> for ImplSubject<'tcx> {
 }
 
 impl<'tcx> ToTrace<'tcx> for Ty<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into())),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::Region<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Regions(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::Regions(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for Const<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into())),
+            values: ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into())),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::GenericArg<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
             values: match (a.unpack(), b.unpack()) {
                 (GenericArgKind::Lifetime(a), GenericArgKind::Lifetime(b)) => {
-                    ValuePairs::Regions(ExpectedFound::new(a_is_expected, a, b))
+                    ValuePairs::Regions(ExpectedFound::new(true, a, b))
                 }
                 (GenericArgKind::Type(a), GenericArgKind::Type(b)) => {
-                    ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into()))
+                    ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into()))
                 }
                 (GenericArgKind::Const(a), GenericArgKind::Const(b)) => {
-                    ValuePairs::Terms(ExpectedFound::new(a_is_expected, a.into(), b.into()))
+                    ValuePairs::Terms(ExpectedFound::new(true, a.into(), b.into()))
                 }
 
                 (
@@ -419,72 +403,47 @@ impl<'tcx> ToTrace<'tcx> for ty::GenericArg<'tcx> {
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::Term<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Terms(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::Terms(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::TraitRef<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::TraitRefs(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::TraitRefs(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::AliasTy<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Aliases(ExpectedFound::new(a_is_expected, a.into(), b.into())),
+            values: ValuePairs::Aliases(ExpectedFound::new(true, a.into(), b.into())),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::AliasTerm<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::Aliases(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::Aliases(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
             values: ValuePairs::PolySigs(ExpectedFound::new(
-                a_is_expected,
+                true,
                 ty::Binder::dummy(a),
                 ty::Binder::dummy(b),
             )),
@@ -493,43 +452,28 @@ impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::PolyFnSig<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::PolySigs(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::PolySigs(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialTraitRef<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::ExistentialTraitRef(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::ExistentialTraitRef(ExpectedFound::new(true, a, b)),
         }
     }
 }
 
 impl<'tcx> ToTrace<'tcx> for ty::PolyExistentialProjection<'tcx> {
-    fn to_trace(
-        cause: &ObligationCause<'tcx>,
-        a_is_expected: bool,
-        a: Self,
-        b: Self,
-    ) -> TypeTrace<'tcx> {
+    fn to_trace(cause: &ObligationCause<'tcx>, a: Self, b: Self) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: cause.clone(),
-            values: ValuePairs::ExistentialProjection(ExpectedFound::new(a_is_expected, a, b)),
+            values: ValuePairs::ExistentialProjection(ExpectedFound::new(true, a, b)),
         }
     }
 }

compiler/rustc_lint/src/foreign_modules.rs

@@ -280,7 +280,7 @@ fn structurally_same_type_impl<'tcx>(
 
         ensure_sufficient_stack(|| {
             match (a.kind(), b.kind()) {
-                (&Adt(a_def, _), &Adt(b_def, _)) => {
+                (&Adt(a_def, a_gen_args), &Adt(b_def, b_gen_args)) => {
                     // Only `repr(C)` types can be compared structurally.
                     if !(a_def.repr().c() && b_def.repr().c()) {
                         return false;
@@ -304,8 +304,8 @@ fn structurally_same_type_impl<'tcx>(
                                 seen_types,
                                 tcx,
                                 param_env,
-                                tcx.type_of(a_did).instantiate_identity(),
-                                tcx.type_of(b_did).instantiate_identity(),
+                                tcx.type_of(a_did).instantiate(tcx, a_gen_args),
+                                tcx.type_of(b_did).instantiate(tcx, b_gen_args),
                                 ckind,
                             )
                         },

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

@@ -448,10 +448,10 @@ where
                 }
             }
         } else {
-            self.delegate.enter_forall(kind, |kind| {
-                let goal = goal.with(self.cx(), ty::Binder::dummy(kind));
-                self.add_goal(GoalSource::InstantiateHigherRanked, goal);
-                self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+            self.enter_forall(kind, |ecx, kind| {
+                let goal = goal.with(ecx.cx(), ty::Binder::dummy(kind));
+                ecx.add_goal(GoalSource::InstantiateHigherRanked, goal);
+                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
             })
         }
     }
@@ -840,12 +840,14 @@ where
         self.delegate.instantiate_binder_with_infer(value)
     }
 
+    /// `enter_forall`, but takes `&mut self` and passes it back through the
+    /// callback since it can't be aliased during the call.
     pub(super) fn enter_forall<T: TypeFoldable<I> + Copy, U>(
-        &self,
+        &mut self,
         value: ty::Binder<I, T>,
-        f: impl FnOnce(T) -> U,
+        f: impl FnOnce(&mut Self, T) -> U,
     ) -> U {
-        self.delegate.enter_forall(value, f)
+        self.delegate.enter_forall(value, |value| f(self, value))
     }
 
     pub(super) fn resolve_vars_if_possible<T>(&self, value: T) -> T