Fallible<_> -> Result<_, NoSolution>

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -27,6 +27,7 @@
 use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::AssertKind;
 use rustc_middle::mir::*;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::adjustment::PointerCast;
 use rustc_middle::ty::cast::CastTy;
 use rustc_middle::ty::subst::{SubstsRef, UserSubsts};
@@ -42,7 +43,7 @@
 use rustc_trait_selection::traits::query::type_op::custom::scrape_region_constraints;
 use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp;
 use rustc_trait_selection::traits::query::type_op::{TypeOp, TypeOpOutput};
-use rustc_trait_selection::traits::query::Fallible;
+
 use rustc_trait_selection::traits::PredicateObligation;
 
 use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
@@ -1133,7 +1134,7 @@ fn sub_types(
         sup: Ty<'tcx>,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
-    ) -> Fallible<()> {
+    ) -> Result<(), NoSolution> {
         // Use this order of parameters because the sup type is usually the
         // "expected" type in diagnostics.
         self.relate_types(sup, ty::Variance::Contravariant, sub, locations, category)
@@ -1146,7 +1147,7 @@ fn eq_types(
         found: Ty<'tcx>,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
-    ) -> Fallible<()> {
+    ) -> Result<(), NoSolution> {
         self.relate_types(expected, ty::Variance::Invariant, found, locations, category)
     }
 
@@ -1158,7 +1159,7 @@ fn relate_type_and_user_type(
         user_ty: &UserTypeProjection,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
-    ) -> Fallible<()> {
+    ) -> Result<(), NoSolution> {
         let annotated_type = self.user_type_annotations[user_ty.base].inferred_ty;
         trace!(?annotated_type);
         let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -3,11 +3,11 @@
 use rustc_infer::infer::NllRegionVariableOrigin;
 use rustc_infer::traits::PredicateObligations;
 use rustc_middle::mir::ConstraintCategory;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::relate::TypeRelation;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
-use rustc_trait_selection::traits::query::Fallible;
 
 use crate::constraints::OutlivesConstraint;
 use crate::diagnostics::UniverseInfo;
@@ -31,7 +31,7 @@ pub(super) fn relate_types(
         b: Ty<'tcx>,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
-    ) -> Fallible<()> {
+    ) -> Result<(), NoSolution> {
         TypeRelating::new(
             self.infcx,
             NllTypeRelatingDelegate::new(self, locations, category, UniverseInfo::relate(a, b)),
@@ -48,7 +48,7 @@ pub(super) fn eq_substs(
         b: ty::SubstsRef<'tcx>,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
-    ) -> Fallible<()> {
+    ) -> Result<(), NoSolution> {
         TypeRelating::new(
             self.infcx,
             NllTypeRelatingDelegate::new(self, locations, category, UniverseInfo::other()),

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -15,7 +15,7 @@
 use crate::infer::nll_relate::{TypeRelating, TypeRelatingDelegate};
 use crate::infer::region_constraints::{Constraint, RegionConstraintData};
 use crate::infer::{DefineOpaqueTypes, InferCtxt, InferOk, InferResult, NllRegionVariableOrigin};
-use crate::traits::query::{Fallible, NoSolution};
+use crate::traits::query::NoSolution;
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use crate::traits::{PredicateObligations, TraitEngine, TraitEngineExt};
 use rustc_data_structures::captures::Captures;
@@ -57,7 +57,7 @@ pub fn make_canonicalized_query_response<T>(
         inference_vars: CanonicalVarValues<'tcx>,
         answer: T,
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, T>>
+    ) -> Result<CanonicalQueryResponse<'tcx, T>, NoSolution>
     where
         T: Debug + TypeFoldable<TyCtxt<'tcx>>,
         Canonical<'tcx, QueryResponse<'tcx, T>>: ArenaAllocatable<'tcx>,

compiler/rustc_middle/src/traits/query.rs

@@ -95,8 +95,6 @@ pub fn new(value: T) -> Self {
 #[derive(Copy, Clone, Debug, HashStable, PartialEq, Eq)]
 pub struct NoSolution;
 
-pub type Fallible<T> = Result<T, NoSolution>;
-
 impl<'tcx> From<TypeError<'tcx>> for NoSolution {
     fn from(_: TypeError<'tcx>) -> NoSolution {
         NoSolution

compiler/rustc_trait_selection/src/infer.rs

@@ -5,7 +5,7 @@
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::infer::canonical::{Canonical, CanonicalQueryResponse, QueryResponse};
-use rustc_middle::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_middle::ty::{GenericArg, ToPredicate};
 use rustc_span::DUMMY_SP;
@@ -82,8 +82,8 @@ pub trait InferCtxtBuilderExt<'tcx> {
     fn enter_canonical_trait_query<K, R>(
         &mut self,
         canonical_key: &Canonical<'tcx, K>,
-        operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, R>>
+        operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Result<R, NoSolution>,
+    ) -> Result<CanonicalQueryResponse<'tcx, R>, NoSolution>
     where
         K: TypeFoldable<TyCtxt<'tcx>>,
         R: Debug + TypeFoldable<TyCtxt<'tcx>>,
@@ -110,8 +110,8 @@ impl<'tcx> InferCtxtBuilderExt<'tcx> for InferCtxtBuilder<'tcx> {
     fn enter_canonical_trait_query<K, R>(
         &mut self,
         canonical_key: &Canonical<'tcx, K>,
-        operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, R>>
+        operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Result<R, NoSolution>,
+    ) -> Result<CanonicalQueryResponse<'tcx, R>, NoSolution>
     where
         K: TypeFoldable<TyCtxt<'tcx>>,
         R: Debug + TypeFoldable<TyCtxt<'tcx>>,

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -14,11 +14,11 @@
 };
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{DefineOpaqueTypes, InferCtxt, InferOk};
-use rustc_infer::traits::query::Fallible;
 use rustc_infer::traits::{
     FulfillmentError, Obligation, ObligationCause, PredicateObligation, TraitEngineExt as _,
 };
 use rustc_middle::arena::ArenaAllocatable;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::TypeFoldable;
@@ -235,7 +235,7 @@ pub fn make_canonicalized_query_response<T>(
         &self,
         inference_vars: CanonicalVarValues<'tcx>,
         answer: T,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, T>>
+    ) -> Result<CanonicalQueryResponse<'tcx, T>, NoSolution>
     where
         T: Debug + TypeFoldable<TyCtxt<'tcx>>,
         Canonical<'tcx, QueryResponse<'tcx, T>>: ArenaAllocatable<'tcx>,

compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs

@@ -1,5 +1,5 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
 
 pub use rustc_middle::traits::query::type_op::AscribeUserType;
@@ -17,7 +17,7 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> {
         tcx.type_op_ascribe_user_type(canonicalized)
     }
 }

compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs

@@ -1,10 +1,10 @@
 use crate::infer::canonical::query_response;
 use crate::infer::InferCtxt;
 use crate::traits::query::type_op::TypeOpOutput;
-use crate::traits::query::Fallible;
 use crate::traits::ObligationCtxt;
 use rustc_errors::ErrorGuaranteed;
 use rustc_infer::infer::region_constraints::RegionConstraintData;
+use rustc_middle::traits::query::NoSolution;
 use rustc_span::source_map::DUMMY_SP;
 use rustc_span::Span;
 
@@ -18,7 +18,7 @@ pub struct CustomTypeOp<F> {
 impl<F> CustomTypeOp<F> {
     pub fn new<'tcx, R>(closure: F, description: &'static str) -> Self
     where
-        F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Fallible<R>,
+        F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>,
     {
         CustomTypeOp { closure, description }
     }
@@ -26,7 +26,7 @@ pub fn new<'tcx, R>(closure: F, description: &'static str) -> Self
 
 impl<'tcx, F, R: fmt::Debug> super::TypeOp<'tcx> for CustomTypeOp<F>
 where
-    F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Fallible<R>,
+    F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>,
 {
     type Output = R;
     /// We can't do any custom error reporting for `CustomTypeOp`, so
@@ -59,7 +59,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 /// constraints that result, creating query-region-constraints.
 pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>(
     infcx: &InferCtxt<'tcx>,
-    op: impl FnOnce(&ObligationCtxt<'_, 'tcx>) -> Fallible<R>,
+    op: impl FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>,
     name: &'static str,
     span: Span,
 ) -> Result<(TypeOpOutput<'tcx, Op>, RegionConstraintData<'tcx>), ErrorGuaranteed> {

compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs

@@ -1,5 +1,5 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
 
 pub use rustc_middle::traits::query::type_op::Eq;
@@ -17,7 +17,7 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> {
         tcx.type_op_eq(canonicalized)
     }
 }

compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs

@@ -1,6 +1,6 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
 use rustc_infer::traits::query::OutlivesBound;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
@@ -28,7 +28,7 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> {
         // FIXME this `unchecked_map` is only necessary because the
         // query is defined as taking a `ParamEnvAnd<Ty>`; it should
         // take an `ImpliedOutlivesBounds` instead

compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs

@@ -2,11 +2,11 @@
     Canonical, CanonicalQueryResponse, OriginalQueryValues, QueryRegionConstraints,
 };
 use crate::infer::{InferCtxt, InferOk};
-use crate::traits::query::Fallible;
 use crate::traits::ObligationCause;
 use rustc_errors::ErrorGuaranteed;
 use rustc_infer::infer::canonical::Certainty;
 use rustc_infer::traits::PredicateObligations;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
 use rustc_span::Span;
@@ -79,18 +79,21 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>>;
+    ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution>;
 
     fn fully_perform_into(
         query_key: ParamEnvAnd<'tcx, Self>,
         infcx: &InferCtxt<'tcx>,
         output_query_region_constraints: &mut QueryRegionConstraints<'tcx>,
-    ) -> Fallible<(
-        Self::QueryResponse,
-        Option<Canonical<'tcx, ParamEnvAnd<'tcx, Self>>>,
-        PredicateObligations<'tcx>,
-        Certainty,
-    )> {
+    ) -> Result<
+        (
+            Self::QueryResponse,
+            Option<Canonical<'tcx, ParamEnvAnd<'tcx, Self>>>,
+            PredicateObligations<'tcx>,
+            Certainty,
+        ),
+        NoSolution,
+    > {
         if let Some(result) = QueryTypeOp::try_fast_path(infcx.tcx, &query_key) {
             return Ok((result, None, vec![], Certainty::Proven));
         }

compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs

@@ -1,5 +1,5 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
 use std::fmt;
@@ -19,7 +19,7 @@ fn try_fast_path(_tcx: TyCtxt<'tcx>, key: &ParamEnvAnd<'tcx, Self>) -> Option<T>
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> {
         T::type_op_method(tcx, canonicalized)
     }
 }
@@ -28,14 +28,14 @@ pub trait Normalizable<'tcx>: fmt::Debug + TypeFoldable<TyCtxt<'tcx>> + Lift<'tc
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self>>;
+    ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution>;
 }
 
 impl<'tcx> Normalizable<'tcx> for Ty<'tcx> {
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> {
         tcx.type_op_normalize_ty(canonicalized)
     }
 }
@@ -44,7 +44,7 @@ impl<'tcx> Normalizable<'tcx> for ty::Predicate<'tcx> {
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> {
         tcx.type_op_normalize_predicate(canonicalized)
     }
 }
@@ -53,7 +53,7 @@ impl<'tcx> Normalizable<'tcx> for ty::PolyFnSig<'tcx> {
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> {
         tcx.type_op_normalize_poly_fn_sig(canonicalized)
     }
 }
@@ -62,7 +62,7 @@ impl<'tcx> Normalizable<'tcx> for ty::FnSig<'tcx> {
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> {
         tcx.type_op_normalize_fn_sig(canonicalized)
     }
 }

compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs

@@ -1,6 +1,6 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
 use crate::traits::query::dropck_outlives::{trivial_dropck_outlives, DropckOutlivesResult};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
@@ -27,7 +27,7 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> {
         // Subtle: note that we are not invoking
         // `infcx.at(...).dropck_outlives(...)` here, but rather the
         // underlying `dropck_outlives` query. This same underlying

compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs

@@ -1,5 +1,5 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{self, ParamEnvAnd, TyCtxt};
 
 pub use rustc_middle::traits::query::type_op::ProvePredicate;
@@ -33,7 +33,7 @@ fn try_fast_path(
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> {
         tcx.type_op_prove_predicate(canonicalized)
     }
 }

compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs

@@ -1,5 +1,5 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
-use crate::traits::query::Fallible;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
 
 pub use rustc_middle::traits::query::type_op::Subtype;
@@ -14,7 +14,7 @@ fn try_fast_path(_tcx: TyCtxt<'tcx>, key: &ParamEnvAnd<'tcx, Self>) -> Option<()
     fn perform_query(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> {
+    ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> {
         tcx.type_op_subtype(canonicalized)
     }
 }

compiler/rustc_traits/src/implied_outlives_bounds.rs

@@ -11,7 +11,7 @@
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::source_map::DUMMY_SP;
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
-use rustc_trait_selection::traits::query::{CanonicalTyGoal, Fallible, NoSolution};
+use rustc_trait_selection::traits::query::{CanonicalTyGoal, NoSolution};
 use rustc_trait_selection::traits::wf;
 use rustc_trait_selection::traits::ObligationCtxt;
 use smallvec::{smallvec, SmallVec};
@@ -37,7 +37,7 @@ fn compute_implied_outlives_bounds<'tcx>(
     ocx: &ObligationCtxt<'_, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     ty: Ty<'tcx>,
-) -> Fallible<Vec<OutlivesBound<'tcx>>> {
+) -> Result<Vec<OutlivesBound<'tcx>>, NoSolution> {
     let tcx = ocx.infcx.tcx;
 
     // Sometimes when we ask what it takes for T: WF, we get back that

compiler/rustc_traits/src/type_op.rs

@@ -2,6 +2,7 @@
 use rustc_infer::infer::canonical::{Canonical, QueryResponse};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::query::Providers;
+use rustc_middle::traits::query::NoSolution;
 use rustc_middle::traits::{DefiningAnchor, ObligationCauseCode};
 use rustc_middle::ty::{self, FnSig, Lift, PolyFnSig, Ty, TyCtxt, TypeFoldable};
 use rustc_middle::ty::{ParamEnvAnd, Predicate};
@@ -15,7 +16,6 @@
 use rustc_trait_selection::traits::query::type_op::normalize::Normalize;
 use rustc_trait_selection::traits::query::type_op::prove_predicate::ProvePredicate;
 use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
-use rustc_trait_selection::traits::query::{Fallible, NoSolution};
 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, ObligationCtxt};
 use std::fmt;
 
@@ -160,7 +160,7 @@ fn type_op_eq<'tcx>(
 fn type_op_normalize<'tcx, T>(
     ocx: &ObligationCtxt<'_, 'tcx>,
     key: ParamEnvAnd<'tcx, Normalize<T>>,
-) -> Fallible<T>
+) -> Result<T, NoSolution>
 where
     T: fmt::Debug + TypeFoldable<TyCtxt<'tcx>> + Lift<'tcx>,
 {