Nits and formatting

compiler/rustc_trait_selection/src/solve/normalize.rs

@@ -1,3 +1,4 @@
+use std::fmt::Debug;
 use std::marker::PhantomData;
 
 use crate::traits::error_reporting::{OverflowCause, TypeErrCtxtExt};
@@ -6,7 +7,7 @@ use crate::traits::{BoundVarReplacer, PlaceholderReplacer, ScrubbedTraitError};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_infer::infer::at::At;
 use rustc_infer::infer::InferCtxt;
-use rustc_infer::traits::{FromSolverError, FulfillmentErrorLike, Obligation, TraitEngine};
+use rustc_infer::traits::{FromSolverError, Obligation, TraitEngine};
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::{self, Ty, TyCtxt, UniverseIndex};
 use rustc_middle::ty::{FallibleTypeFolder, TypeFolder, TypeSuperFoldable};
@@ -16,14 +17,11 @@ use super::{FulfillmentCtxt, NextSolverError};
 
 /// Deeply normalize all aliases in `value`. This does not handle inference and expects
 /// its input to be already fully resolved.
-pub fn deeply_normalize<
-    'tcx,
+pub fn deeply_normalize<'tcx, T, E>(at: At<'_, 'tcx>, value: T) -> Result<T, Vec<E>>
+where
     T: TypeFoldable<TyCtxt<'tcx>>,
     E: FromSolverError<'tcx, NextSolverError<'tcx>>,
->(
-    at: At<'_, 'tcx>,
-    value: T,
-) -> Result<T, Vec<E>> {
+{
     assert!(!value.has_escaping_bound_vars());
     deeply_normalize_with_skipped_universes(at, value, vec![])
 }
@@ -34,15 +32,15 @@ pub fn deeply_normalize<
 /// Additionally takes a list of universes which represents the binders which have been
 /// entered before passing `value` to the function. This is currently needed for
 /// `normalize_erasing_regions`, which skips binders as it walks through a type.
-pub fn deeply_normalize_with_skipped_universes<
-    'tcx,
-    T: TypeFoldable<TyCtxt<'tcx>>,
-    E: FromSolverError<'tcx, NextSolverError<'tcx>>,
->(
+pub fn deeply_normalize_with_skipped_universes<'tcx, T, E>(
     at: At<'_, 'tcx>,
     value: T,
     universes: Vec<Option<UniverseIndex>>,
-) -> Result<T, Vec<E>> {
+) -> Result<T, Vec<E>>
+where
+    T: TypeFoldable<TyCtxt<'tcx>>,
+    E: FromSolverError<'tcx, NextSolverError<'tcx>>,
+{
     let fulfill_cx = FulfillmentCtxt::new(at.infcx);
     let mut folder =
         NormalizationFolder { at, fulfill_cx, depth: 0, universes, _errors: PhantomData };
@@ -50,7 +48,7 @@ pub fn deeply_normalize_with_skipped_universes<
     value.try_fold_with(&mut folder)
 }
 
-struct NormalizationFolder<'me, 'tcx, E: FulfillmentErrorLike<'tcx>> {
+struct NormalizationFolder<'me, 'tcx, E> {
     at: At<'me, 'tcx>,
     fulfill_cx: FulfillmentCtxt<'tcx, E>,
     depth: usize,
@@ -58,7 +56,10 @@ struct NormalizationFolder<'me, 'tcx, E: FulfillmentErrorLike<'tcx>> {
     _errors: PhantomData<E>,
 }
 
-impl<'tcx, E: FromSolverError<'tcx, NextSolverError<'tcx>>> NormalizationFolder<'_, 'tcx, E> {
+impl<'tcx, E> NormalizationFolder<'_, 'tcx, E>
+where
+    E: FromSolverError<'tcx, NextSolverError<'tcx>>,
+{
     fn normalize_alias_ty(&mut self, alias_ty: Ty<'tcx>) -> Result<Ty<'tcx>, Vec<E>> {
         assert!(matches!(alias_ty.kind(), ty::Alias(..)));
 
@@ -150,8 +151,9 @@ impl<'tcx, E: FromSolverError<'tcx, NextSolverError<'tcx>>> NormalizationFolder<
     }
 }
 
-impl<'tcx, E: FromSolverError<'tcx, NextSolverError<'tcx>>> FallibleTypeFolder<TyCtxt<'tcx>>
-    for NormalizationFolder<'_, 'tcx, E>
+impl<'tcx, E> FallibleTypeFolder<TyCtxt<'tcx>> for NormalizationFolder<'_, 'tcx, E>
+where
+    E: FromSolverError<'tcx, NextSolverError<'tcx>> + Debug,
 {
     type Error = Vec<E>;