Auto merge of #104905 - compiler-errors:normalization-changes, r=spastorino

Some initial normalization method changes

1. Rename `AtExt::normalize` to `QueryNormalizeExt::query_normalize` (using the `QueryNormalizer`)
2. Introduce `NormalizeExt::normalize` to replace `partially_normalize_associated_types_in` (using the `AssocTypeNormalizer`)
3. Rename `FnCtxt::normalize_associated_types_in` to `FnCtxt::normalize`
4. Remove some unused other normalization fns in `Inherited` and `FnCtxt`

Also includes one drive-by where we're no longer creating a `FnCtxt` inside of `check_fn`, but passing it in. This means we don't need such weird `FnCtxt` construction logic.

Stacked on top of #104835 for convenience.

r? types

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -291,11 +291,11 @@ where
         // FIXME(lqd): Unify and de-duplicate the following with the actual
         // `rustc_traits::type_op::type_op_normalize` query to allow the span we need in the
         // `ObligationCause`. The normalization results are currently different between
-        // `AtExt::normalize` used in the query and `normalize` called below: the former fails
+        // `QueryNormalizeExt::query_normalize` used in the query and `normalize` called below:
-        // to normalize the `nll/relate_tys/impl-fn-ignore-binder-via-bottom.rs` test. Check
+        // the former fails to normalize the `nll/relate_tys/impl-fn-ignore-binder-via-bottom.rs` test.
-        // after #85499 lands to see if its fixes have erased this difference.
+        // Check after #85499 lands to see if its fixes have erased this difference.
         let (param_env, value) = key.into_parts();
-        let _ = ocx.normalize(cause, param_env, value.value);
+        let _ = ocx.normalize(&cause, param_env, value.value);
 
         try_extract_error_from_fulfill_cx(&ocx, placeholder_region, error_region)
     }

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -761,8 +761,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                             hir_id,
                             ObligationCauseCode::ItemObligation(callee),
                         );
-                        let normalized_predicates =
+                        let normalized_predicates = ocx.normalize(&cause, param_env, predicates);
-                            ocx.normalize(cause.clone(), param_env, predicates);
                         ocx.register_obligations(traits::predicates_for_generics(
                             |_, _| cause.clone(),
                             self.param_env,

compiler/rustc_const_eval/src/util/compare_types.rs

@@ -46,8 +46,8 @@ pub fn is_subtype<'tcx>(
     let infcx = builder.build();
     let ocx = ObligationCtxt::new(&infcx);
     let cause = ObligationCause::dummy();
-    let src = ocx.normalize(cause.clone(), param_env, src);
+    let src = ocx.normalize(&cause, param_env, src);
-    let dest = ocx.normalize(cause.clone(), param_env, dest);
+    let dest = ocx.normalize(&cause, param_env, dest);
     match ocx.sub(&cause, param_env, src, dest) {
         Ok(()) => {}
         Err(_) => return false,

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -109,6 +109,9 @@ pub trait AstConv<'tcx> {
     ) -> Ty<'tcx>;
 
     /// Normalize an associated type coming from the user.
+    ///
+    /// This should only be used by astconv. Use `FnCtxt::normalize`
+    /// or `ObligationCtxt::normalize` in downstream crates.
     fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx>;
 
     /// Invoked when we encounter an error from some prior pass

compiler/rustc_hir_analysis/src/check/compare_method.rs

@@ -221,7 +221,7 @@ fn compare_predicate_entailment<'tcx>(
     let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs);
     for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) {
         let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id);
-        let predicate = ocx.normalize(normalize_cause, param_env, predicate);
+        let predicate = ocx.normalize(&normalize_cause, param_env, predicate);
 
         let cause = ObligationCause::new(
             span,
@@ -260,7 +260,7 @@ fn compare_predicate_entailment<'tcx>(
     );
 
     let norm_cause = ObligationCause::misc(impl_m_span, impl_m_hir_id);
-    let impl_sig = ocx.normalize(norm_cause.clone(), param_env, impl_sig);
+    let impl_sig = ocx.normalize(&norm_cause, param_env, impl_sig);
     let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig));
     debug!("compare_impl_method: impl_fty={:?}", impl_fty);
 
@@ -271,7 +271,7 @@ fn compare_predicate_entailment<'tcx>(
     // we have to do this before normalization, since the normalized ty may
     // not contain the input parameters. See issue #87748.
     wf_tys.extend(trait_sig.inputs_and_output.iter());
-    let trait_sig = ocx.normalize(norm_cause, param_env, trait_sig);
+    let trait_sig = ocx.normalize(&norm_cause, param_env, trait_sig);
     // We also have to add the normalized trait signature
     // as we don't normalize during implied bounds computation.
     wf_tys.extend(trait_sig.inputs_and_output.iter());
@@ -366,7 +366,7 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
     // Normalize the impl signature with fresh variables for lifetime inference.
     let norm_cause = ObligationCause::misc(return_span, impl_m_hir_id);
     let impl_sig = ocx.normalize(
-        norm_cause.clone(),
+        &norm_cause,
         param_env,
         infcx.replace_bound_vars_with_fresh_vars(
             return_span,
@@ -387,7 +387,7 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
             tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs),
         )
         .fold_with(&mut collector);
-    let trait_sig = ocx.normalize(norm_cause.clone(), param_env, unnormalized_trait_sig);
+    let trait_sig = ocx.normalize(&norm_cause, param_env, unnormalized_trait_sig);
     let trait_return_ty = trait_sig.output();
 
     let wf_tys = FxIndexSet::from_iter(
@@ -592,7 +592,7 @@ impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> {
             for (pred, pred_span) in self.tcx().bound_explicit_item_bounds(proj.item_def_id).subst_iter_copied(self.tcx(), proj.substs) {
                 let pred = pred.fold_with(self);
                 let pred = self.ocx.normalize(
-                    ObligationCause::misc(self.span, self.body_id),
+                    &ObligationCause::misc(self.span, self.body_id),
                     self.param_env,
                     pred,
                 );
@@ -1403,11 +1403,11 @@ pub(crate) fn raw_compare_const_impl<'tcx>(
     );
 
     // There is no "body" here, so just pass dummy id.
-    let impl_ty = ocx.normalize(cause.clone(), param_env, impl_ty);
+    let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
 
     debug!("compare_const_impl: impl_ty={:?}", impl_ty);
 
-    let trait_ty = ocx.normalize(cause.clone(), param_env, trait_ty);
+    let trait_ty = ocx.normalize(&cause, param_env, trait_ty);
 
     debug!("compare_const_impl: trait_ty={:?}", trait_ty);
 
@@ -1556,7 +1556,7 @@ fn compare_type_predicate_entailment<'tcx>(
     for (span, predicate) in std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates)
     {
         let cause = ObligationCause::misc(span, impl_ty_hir_id);
-        let predicate = ocx.normalize(cause, param_env, predicate);
+        let predicate = ocx.normalize(&cause, param_env, predicate);
 
         let cause = ObligationCause::new(
             span,
@@ -1778,7 +1778,7 @@ pub fn check_type_bounds<'tcx>(
 
     for mut obligation in util::elaborate_obligations(tcx, obligations) {
         let normalized_predicate =
-            ocx.normalize(normalize_cause.clone(), normalize_param_env, obligation.predicate);
+            ocx.normalize(&normalize_cause, normalize_param_env, obligation.predicate);
         debug!("compare_projection_bounds: normalized predicate = {:?}", normalized_predicate);
         obligation.predicate = normalized_predicate;
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -53,12 +53,14 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
         self.ocx.infcx.tcx
     }
 
+    // Convenience function to normalize during wfcheck. This performs
+    // `ObligationCtxt::normalize`, but provides a nice `ObligationCauseCode`.
     fn normalize<T>(&self, span: Span, loc: Option<WellFormedLoc>, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {
         self.ocx.normalize(
-            ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)),
+            &ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)),
             self.param_env,
             value,
         )

compiler/rustc_hir_analysis/src/lib.rs

@@ -332,7 +332,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
             ObligationCauseCode::MainFunctionType,
         );
         let ocx = traits::ObligationCtxt::new(&infcx);
-        let norm_return_ty = ocx.normalize(cause.clone(), param_env, return_ty);
+        let norm_return_ty = ocx.normalize(&cause, param_env, return_ty);
         ocx.register_bound(cause, param_env, norm_return_ty, term_did);
         let errors = ocx.select_all_or_error();
         if !errors.is_empty() {

compiler/rustc_hir_typeck/src/callee.rs

@@ -448,7 +448,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // previously appeared within a `Binder<>` and hence would not
         // have been normalized before.
         let fn_sig = self.replace_bound_vars_with_fresh_vars(call_expr.span, infer::FnCall, fn_sig);
-        let fn_sig = self.normalize_associated_types_in(call_expr.span, fn_sig);
+        let fn_sig = self.normalize(call_expr.span, fn_sig);
 
         // Call the generic checker.
         let expected_arg_tys = self.expected_inputs_for_expected_output(

compiler/rustc_hir_typeck/src/cast.rs

@@ -752,10 +752,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 match *self.expr_ty.kind() {
                     ty::FnDef(..) => {
                         // Attempt a coercion to a fn pointer type.
-                        let f = fcx.normalize_associated_types_in(
+                        let f = fcx.normalize(self.expr_span, self.expr_ty.fn_sig(fcx.tcx));
-                            self.expr_span,
-                            self.expr_ty.fn_sig(fcx.tcx),
-                        );
                         let res = fcx.try_coerce(
                             self.expr,
                             self.expr_ty,

compiler/rustc_hir_typeck/src/check.rs

@@ -1,6 +1,6 @@
 use crate::coercion::CoerceMany;
 use crate::gather_locals::GatherLocalsVisitor;
-use crate::{FnCtxt, Inherited};
+use crate::FnCtxt;
 use crate::{GeneratorTypes, UnsafetyState};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -20,21 +20,16 @@ use std::cell::RefCell;
 ///
 /// * ...
 /// * inherited: other fields inherited from the enclosing fn (if any)
-#[instrument(skip(inherited, body), level = "debug")]
+#[instrument(skip(fcx, body), level = "debug")]
 pub(super) fn check_fn<'a, 'tcx>(
-    inherited: &'a Inherited<'tcx>,
+    fcx: &mut FnCtxt<'a, 'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
     fn_sig: ty::FnSig<'tcx>,
     decl: &'tcx hir::FnDecl<'tcx>,
     fn_def_id: LocalDefId,
     body: &'tcx hir::Body<'tcx>,
     can_be_generator: Option<hir::Movability>,
-) -> (FnCtxt<'a, 'tcx>, Option<GeneratorTypes<'tcx>>) {
+) -> Option<GeneratorTypes<'tcx>> {
-    let fn_id = inherited.tcx.hir().local_def_id_to_hir_id(fn_def_id);
+    let fn_id = fcx.tcx.hir().local_def_id_to_hir_id(fn_def_id);
-
-    // Create the function context. This is either derived from scratch or,
-    // in the case of closures, based on the outer context.
-    let mut fcx = FnCtxt::new(inherited, param_env, body.value.hir_id);
     fcx.ps.set(UnsafetyState::function(fn_sig.unsafety, fn_id));
 
     let tcx = fcx.tcx;
@@ -47,7 +42,7 @@ pub(super) fn check_fn<'a, 'tcx>(
             declared_ret_ty,
             body.value.hir_id,
             decl.output.span(),
-            param_env,
+            fcx.param_env,
         ));
 
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty)));
@@ -105,7 +100,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         fcx.write_ty(param.hir_id, param_ty);
     }
 
-    inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
+    fcx.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
 
     if let ty::Dynamic(_, _, ty::Dyn) = declared_ret_ty.kind() {
         // FIXME: We need to verify that the return type is `Sized` after the return expression has
@@ -174,7 +169,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         check_panic_info_fn(tcx, panic_impl_did.expect_local(), fn_sig, decl, declared_ret_ty);
     }
 
-    (fcx, gen_ty)
+    gen_ty
 }
 
 fn check_panic_info_fn(

compiler/rustc_hir_typeck/src/closure.rs

@@ -79,16 +79,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         debug!(?bound_sig, ?liberated_sig);
 
+        let mut fcx = FnCtxt::new(self, self.param_env.without_const(), body.value.hir_id);
         let generator_types = check_fn(
-            self,
+            &mut fcx,
-            self.param_env.without_const(),
             liberated_sig,
             closure.fn_decl,
             expr_def_id,
             body,
             closure.movability,
-        )
+        );
-        .1;
 
         let parent_substs = InternalSubsts::identity_for_item(
             self.tcx,
@@ -214,7 +213,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if expected_sig.is_none()
                 && let ty::PredicateKind::Clause(ty::Clause::Projection(proj_predicate)) = bound_predicate.skip_binder()
             {
-                expected_sig = self.normalize_associated_types_in(
+                expected_sig = self.normalize(
                     obligation.cause.span,
                     self.deduce_sig_from_projection(
                     Some(obligation.cause.span),
@@ -623,7 +622,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         );
         // Astconv can't normalize inputs or outputs with escaping bound vars,
         // so normalize them here, after we've wrapped them in a binder.
-        let result = self.normalize_associated_types_in(self.tcx.hir().span(hir_id), result);
+        let result = self.normalize(self.tcx.hir().span(hir_id), result);
 
         let c_result = self.inh.infcx.canonicalize_response(result);
         self.typeck_results.borrow_mut().user_provided_sigs.insert(expr_def_id, c_result);
@@ -797,12 +796,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> ClosureSignatures<'tcx> {
         let liberated_sig =
             self.tcx().liberate_late_bound_regions(expr_def_id.to_def_id(), bound_sig);
-        let liberated_sig = self.inh.normalize_associated_types_in(
+        let liberated_sig = self.normalize(body.value.span, liberated_sig);
-            body.value.span,
-            self.tcx.hir().local_def_id_to_hir_id(expr_def_id),
-            self.param_env,
-            liberated_sig,
-        );
         ClosureSignatures { bound_sig, liberated_sig }
     }
 }

compiler/rustc_hir_typeck/src/coercion.rs

@@ -62,7 +62,9 @@ use rustc_span::{self, BytePos, DesugaringKind, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode, ObligationCtxt};
+use rustc_trait_selection::traits::{
+    self, NormalizeExt, ObligationCause, ObligationCauseCode, ObligationCtxt,
+};
 
 use smallvec::{smallvec, SmallVec};
 use std::ops::Deref;
@@ -832,7 +834,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
 
         let b = self.shallow_resolve(b);
         let InferOk { value: b, mut obligations } =
-            self.normalize_associated_types_in_as_infer_ok(self.cause.span, b);
+            self.at(&self.cause, self.param_env).normalize(b);
         debug!("coerce_from_fn_item(a={:?}, b={:?})", a, b);
 
         match b.kind() {
@@ -854,7 +856,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 }
 
                 let InferOk { value: a_sig, obligations: o1 } =
-                    self.normalize_associated_types_in_as_infer_ok(self.cause.span, a_sig);
+                    self.at(&self.cause, self.param_env).normalize(a_sig);
                 obligations.extend(o1);
 
                 let a_fn_pointer = self.tcx.mk_fn_ptr(a_sig);
@@ -1141,8 +1143,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return Err(TypeError::IntrinsicCast);
             }
             // The signature must match.
-            let a_sig = self.normalize_associated_types_in(new.span, a_sig);
+            let (a_sig, b_sig) = self.normalize(new.span, (a_sig, b_sig));
-            let b_sig = self.normalize_associated_types_in(new.span, b_sig);
             let sig = self
                 .at(cause, self.param_env)
                 .trace(prev_ty, new_ty)

compiler/rustc_hir_typeck/src/expr.rs

@@ -1664,7 +1664,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .fields
                         .iter()
                         .map(|f| {
-                            let fru_ty = self.normalize_associated_types_in(
+                            let fru_ty = self.normalize(
                                 expr_span,
                                 self.field_ty(base_expr.span, f, fresh_substs),
                             );
@@ -1748,9 +1748,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ty::Adt(adt, substs) if adt.is_struct() => variant
                         .fields
                         .iter()
-                        .map(|f| {
+                        .map(|f| self.normalize(expr_span, f.ty(self.tcx, substs)))
-                            self.normalize_associated_types_in(expr_span, f.ty(self.tcx, substs))
-                        })
                         .collect(),
                     _ => {
                         self.tcx

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -16,7 +16,7 @@ use rustc_hir_analysis::astconv::{
 };
 use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
-use rustc_infer::infer::{InferOk, InferResult};
+use rustc_infer::infer::InferResult;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::fold::TypeFoldable;
@@ -30,9 +30,8 @@ use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode, ObligationCtxt};
+use rustc_trait_selection::traits::{self, NormalizeExt, ObligationCauseCode, ObligationCtxt};
 
 use std::collections::hash_map::Entry;
 use std::slice;
@@ -343,7 +342,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     {
         debug!("instantiate_type_scheme(value={:?}, substs={:?})", value, substs);
         let value = EarlyBinder(value).subst(self.tcx, substs);
-        let result = self.normalize_associated_types_in(span, value);
+        let result = self.normalize(span, value);
         debug!("instantiate_type_scheme = {:?}", result);
         result
     }
@@ -359,7 +358,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let bounds = self.tcx.predicates_of(def_id);
         let spans: Vec<Span> = bounds.predicates.iter().map(|(_, span)| *span).collect();
         let result = bounds.instantiate(self.tcx, substs);
-        let result = self.normalize_associated_types_in(span, result);
+        let result = self.normalize(span, result);
         debug!(
             "instantiate_bounds(bounds={:?}, substs={:?}) = {:?}, {:?}",
             bounds, substs, result, spans,
@@ -367,50 +366,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         (result, spans)
     }
 
-    pub(in super::super) fn normalize_associated_types_in<T>(&self, span: Span, value: T) -> T
+    pub(in super::super) fn normalize<T>(&self, span: Span, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {
-        self.inh.normalize_associated_types_in(span, self.body_id, self.param_env, value)
+        self.register_infer_ok_obligations(
-    }
+            self.at(&self.misc(span), self.param_env).normalize(value),
-
-    pub(in super::super) fn normalize_associated_types_in_as_infer_ok<T>(
-        &self,
-        span: Span,
-        value: T,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        self.inh.partially_normalize_associated_types_in(
-            ObligationCause::misc(span, self.body_id),
-            self.param_env,
-            value,
-        )
-    }
-
-    pub(in super::super) fn normalize_op_associated_types_in_as_infer_ok<T>(
-        &self,
-        span: Span,
-        value: T,
-        opt_input_expr: Option<&hir::Expr<'_>>,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        self.inh.partially_normalize_associated_types_in(
-            ObligationCause::new(
-                span,
-                self.body_id,
-                traits::BinOp {
-                    rhs_span: opt_input_expr.map(|expr| expr.span),
-                    is_lit: opt_input_expr
-                        .map_or(false, |expr| matches!(expr.kind, ExprKind::Lit(_))),
-                    output_ty: None,
-                },
-            ),
-            self.param_env,
-            value,
         )
     }
 
@@ -490,7 +451,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let span = self.tcx.def_span(anon_const.def_id);
                 let c = ty::Const::from_anon_const(self.tcx, anon_const.def_id);
                 self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
-                self.normalize_associated_types_in(span, c)
+                self.normalize(span, c)
             }
         }
     }
@@ -583,7 +544,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         field: &'tcx ty::FieldDef,
         substs: SubstsRef<'tcx>,
     ) -> Ty<'tcx> {
-        self.normalize_associated_types_in(span, field.ty(self.tcx, substs))
+        self.normalize(span, field.ty(self.tcx, substs))
     }
 
     pub(in super::super) fn resolve_rvalue_scopes(&self, def_id: DefId) {
@@ -1110,7 +1071,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         if let Res::Local(hid) = res {
             let ty = self.local_ty(span, hid).decl_ty;
-            let ty = self.normalize_associated_types_in(span, ty);
+            let ty = self.normalize(span, ty);
             self.write_ty(hir_id, ty);
             return (ty, res);
         }

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -288,7 +288,7 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
         if ty.has_escaping_bound_vars() {
             ty // FIXME: normalization and escaping regions
         } else {
-            self.normalize_associated_types_in(span, ty)
+            self.normalize(span, ty)
         }
     }
 

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -20,6 +20,7 @@ use rustc_span::Span;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::error_reporting::DefIdOrName;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
+use rustc_trait_selection::traits::NormalizeExt;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(crate) fn body_fn_sig(&self) -> Option<ty::FnSig<'tcx>> {
@@ -245,7 +246,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // implied by wf, but also because that would possibly result in
         // erroneous errors later on.
         let infer::InferOk { value: output, obligations: _ } =
-            self.normalize_associated_types_in_as_infer_ok(expr.span, output);
+            self.at(&self.misc(expr.span), self.param_env).normalize(output);
 
         if output.is_ty_var() { None } else { Some((def_id_or_name, output, inputs)) }
     }
@@ -759,7 +760,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 debug!("suggest_missing_return_type: expected type {:?}", ty);
                 let bound_vars = self.tcx.late_bound_vars(fn_id);
                 let ty = Binder::bind_with_vars(ty, bound_vars);
-                let ty = self.normalize_associated_types_in(span, ty);
+                let ty = self.normalize(span, ty);
                 let ty = self.tcx.erase_late_bound_regions(ty);
                 if self.can_coerce(expected, ty) {
                     err.subdiagnostic(ExpectedReturnTypeLabel::Other { span, expected });
@@ -920,7 +921,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, ty);
             let bound_vars = self.tcx.late_bound_vars(fn_id);
             let ty = self.tcx.erase_late_bound_regions(Binder::bind_with_vars(ty, bound_vars));
-            let ty = self.normalize_associated_types_in(expr.span, ty);
+            let ty = self.normalize(expr.span, ty);
             let ty = match self.tcx.asyncness(fn_id.owner) {
                 hir::IsAsync::Async => {
                     let infcx = self.tcx.infer_ctxt().build();

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -235,7 +235,7 @@ pub fn resolve_interior<'a, 'tcx>(
                 counter += 1;
                 ty::BoundRegion { var, kind }
             };
-            let ty = fcx.normalize_associated_types_in(cause.span, cause.ty);
+            let ty = fcx.normalize(cause.span, cause.ty);
             let ty = fcx.tcx.fold_regions(ty, |region, current_depth| {
                 let br = match region.kind() {
                     ty::ReVar(vid) => {

compiler/rustc_hir_typeck/src/inherited.rs

@@ -7,12 +7,10 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_hir::HirIdMap;
 use rustc_infer::infer;
 use rustc_infer::infer::{DefiningAnchor, InferCtxt, InferOk, TyCtxtInferExt};
-use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::LocalDefIdMap;
 use rustc_span::{self, Span};
-use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
     self, ObligationCause, ObligationCtxt, TraitEngine, TraitEngineExt as _,
 };
@@ -102,7 +100,7 @@ impl<'tcx> Inherited<'tcx> {
                     infcx.probe(|_| {
                         let ocx = ObligationCtxt::new_in_snapshot(infcx);
                         let normalized_fn_sig = ocx.normalize(
-                            ObligationCause::dummy(),
+                            &ObligationCause::dummy(),
                             // FIXME(compiler-errors): This is probably not the right param-env...
                             infcx.tcx.param_env(def_id),
                             fn_sig,
@@ -179,35 +177,4 @@ impl<'tcx> Inherited<'tcx> {
         self.register_predicates(infer_ok.obligations);
         infer_ok.value
     }
-
-    pub(super) fn normalize_associated_types_in<T>(
-        &self,
-        span: Span,
-        body_id: hir::HirId,
-        param_env: ty::ParamEnv<'tcx>,
-        value: T,
-    ) -> T
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        self.normalize_associated_types_in_with_cause(
-            ObligationCause::misc(span, body_id),
-            param_env,
-            value,
-        )
-    }
-
-    pub(super) fn normalize_associated_types_in_with_cause<T>(
-        &self,
-        cause: ObligationCause<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-        value: T,
-    ) -> T
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        let ok = self.partially_normalize_associated_types_in(cause, param_env, value);
-        debug!(?ok);
-        self.register_infer_ok_obligations(ok)
-    }
 }

compiler/rustc_hir_typeck/src/lib.rs

@@ -233,9 +233,10 @@ fn typeck_with_fallback<'tcx>(
 
     let typeck_results = Inherited::build(tcx, def_id).enter(|inh| {
         let param_env = tcx.param_env(def_id);
-        let mut fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+        let mut fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
+
+        if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
             let fn_sig = if rustc_hir_analysis::collect::get_infer_ret_ty(&decl.output).is_some() {
-                let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
                 <dyn AstConv<'_>>::ty_of_fn(&fcx, id, header.unsafety, header.abi, decl, None, None)
             } else {
                 tcx.fn_sig(def_id)
@@ -245,15 +246,10 @@ fn typeck_with_fallback<'tcx>(
 
             // Compute the function signature from point of view of inside the fn.
             let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
-            let fn_sig = inh.normalize_associated_types_in(
+            let fn_sig = fcx.normalize(body.value.span, fn_sig);
-                body.value.span,
+
-                body_id.hir_id,
+            check_fn(&mut fcx, fn_sig, decl, def_id, body, None);
-                param_env,
-                fn_sig,
-            );
-            check_fn(&inh, param_env, fn_sig, decl, def_id, body, None).0
         } else {
-            let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
             let expected_type = body_ty
                 .and_then(|ty| match ty.kind {
                     hir::TyKind::Infer => Some(<dyn AstConv<'_>>::ast_ty_to_ty(&fcx, ty)),
@@ -304,7 +300,7 @@ fn typeck_with_fallback<'tcx>(
                     _ => fallback(),
                 });
 
-            let expected_type = fcx.normalize_associated_types_in(body.value.span, expected_type);
+            let expected_type = fcx.normalize(body.value.span, expected_type);
             fcx.require_type_is_sized(expected_type, body.value.span, traits::ConstSized);
 
             // Gather locals in statics (because of block expressions).
@@ -313,8 +309,6 @@ fn typeck_with_fallback<'tcx>(
             fcx.check_expr_coercable_to_type(&body.value, expected_type, None);
 
             fcx.write_ty(id, expected_type);
-
-            fcx
         };
 
         fcx.type_inference_fallback();

compiler/rustc_hir_typeck/src/method/confirm.rs

@@ -106,7 +106,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         // traits, no trait system method can be called before this point because they
         // could alter our Self-type, except for normalizing the receiver from the
         // signature (which is also done during probing).
-        let method_sig_rcvr = self.normalize_associated_types_in(self.span, method_sig.inputs()[0]);
+        let method_sig_rcvr = self.normalize(self.span, method_sig.inputs()[0]);
         debug!(
             "confirm: self_ty={:?} method_sig_rcvr={:?} method_sig={:?} method_predicates={:?}",
             self_ty, method_sig_rcvr, method_sig, method_predicates
@@ -114,7 +114,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         self.unify_receivers(self_ty, method_sig_rcvr, &pick, all_substs);
 
         let (method_sig, method_predicates) =
-            self.normalize_associated_types_in(self.span, (method_sig, method_predicates));
+            self.normalize(self.span, (method_sig, method_predicates));
         let method_sig = ty::Binder::dummy(method_sig);
 
         // Make sure nobody calls `drop()` explicitly.

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -23,8 +23,8 @@ use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
 use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, Ty, TypeVisitable};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
-use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
+use rustc_trait_selection::traits::{self, NormalizeExt};
 
 use self::probe::{IsSuggestion, ProbeScope};
 
@@ -465,11 +465,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let fn_sig = fn_sig.subst(self.tcx, substs);
         let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig);
 
-        let InferOk { value, obligations: o } = if is_op {
+        let cause = if is_op {
-            self.normalize_op_associated_types_in_as_infer_ok(span, fn_sig, opt_input_expr)
+            ObligationCause::new(
+                span,
+                self.body_id,
+                traits::BinOp {
+                    rhs_span: opt_input_expr.map(|expr| expr.span),
+                    is_lit: opt_input_expr
+                        .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
+                    output_ty: None,
+                },
+            )
         } else {
-            self.normalize_associated_types_in_as_infer_ok(span, fn_sig)
+            traits::ObligationCause::misc(span, self.body_id)
         };
+
+        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(fn_sig);
         let fn_sig = {
             obligations.extend(o);
             value
@@ -485,11 +496,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // any late-bound regions appearing in its bounds.
         let bounds = self.tcx.predicates_of(def_id).instantiate(self.tcx, substs);
 
-        let InferOk { value, obligations: o } = if is_op {
+        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(bounds);
-            self.normalize_op_associated_types_in_as_infer_ok(span, bounds, opt_input_expr)
-        } else {
-            self.normalize_associated_types_in_as_infer_ok(span, bounds)
-        };
         let bounds = {
             obligations.extend(o);
             value
@@ -497,20 +504,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         assert!(!bounds.has_escaping_bound_vars());
 
-        let cause = if is_op {
-            ObligationCause::new(
-                span,
-                self.body_id,
-                traits::BinOp {
-                    rhs_span: opt_input_expr.map(|expr| expr.span),
-                    is_lit: opt_input_expr
-                        .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                    output_ty: None,
-                },
-            )
-        } else {
-            traits::ObligationCause::misc(span, self.body_id)
-        };
         let predicates_cause = cause.clone();
         obligations.extend(traits::predicates_for_generics(
             move |_, _| predicates_cause.clone(),

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -31,13 +31,13 @@ use rustc_span::lev_distance::{
 use rustc_span::symbol::sym;
 use rustc_span::{symbol::Ident, Span, Symbol, DUMMY_SP};
 use rustc_trait_selection::autoderef::{self, Autoderef};
-use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::query::method_autoderef::MethodAutoderefBadTy;
 use rustc_trait_selection::traits::query::method_autoderef::{
     CandidateStep, MethodAutoderefStepsResult,
 };
 use rustc_trait_selection::traits::query::CanonicalTyGoal;
+use rustc_trait_selection::traits::NormalizeExt;
 use rustc_trait_selection::traits::{self, ObligationCause};
 use std::cmp::max;
 use std::iter;
@@ -716,9 +716,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             // maybe shouldn't include `Param`s, but rather fresh variables or be canonicalized,
             // see issue #89650
             let cause = traits::ObligationCause::misc(self.span, self.body_id);
-            let InferOk { value: xform_self_ty, obligations } = self
+            let InferOk { value: xform_self_ty, obligations } =
-                .fcx
+                self.fcx.at(&cause, self.param_env).normalize(xform_self_ty);
-                .partially_normalize_associated_types_in(cause, self.param_env, xform_self_ty);
 
             debug!(
                 "assemble_inherent_impl_probe after normalization: xform_self_ty = {:?}/{:?}",
@@ -1507,11 +1506,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let InferOk {
                         value: normalized_xform_ret_ty,
                         obligations: normalization_obligations,
-                    } = self.fcx.partially_normalize_associated_types_in(
+                    } = self.fcx.at(&cause, self.param_env).normalize(probe.xform_ret_ty);
-                        cause.clone(),
-                        self.param_env,
-                        probe.xform_ret_ty,
-                    );
                     xform_ret_ty = normalized_xform_ret_ty;
                     debug!("xform_ret_ty after normalization: {:?}", xform_ret_ty);
 
@@ -1521,11 +1516,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let impl_bounds = impl_bounds.instantiate(self.tcx, substs);
 
                     let InferOk { value: impl_bounds, obligations: norm_obligations } =
-                        self.fcx.partially_normalize_associated_types_in(
+                        self.fcx.at(&cause, self.param_env).normalize(impl_bounds);
-                            cause.clone(),
-                            self.param_env,
-                            impl_bounds,
-                        );
 
                     // Convert the bounds into obligations.
                     let impl_obligations = traits::predicates_for_generics(

compiler/rustc_trait_selection/src/autoderef.rs

@@ -1,6 +1,6 @@
 use crate::errors::AutoDerefReachedRecursionLimit;
-use crate::infer::InferCtxtExt as _;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
+use crate::traits::NormalizeExt;
 use crate::traits::{self, TraitEngine, TraitEngineExt};
 use rustc_hir as hir;
 use rustc_infer::infer::InferCtxt;
@@ -138,11 +138,10 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
             return None;
         }
 
-        let normalized_ty = self.infcx.partially_normalize_associated_types_in(
+        let normalized_ty = self
-            cause,
+            .infcx
-            self.param_env,
+            .at(&cause, self.param_env)
-            tcx.mk_projection(tcx.lang_items().deref_target()?, trait_ref.substs),
+            .normalize(tcx.mk_projection(tcx.lang_items().deref_target()?, trait_ref.substs));
-        );
         let mut fulfillcx = <dyn TraitEngine<'tcx>>::new_in_snapshot(tcx);
         let normalized_ty =
             normalized_ty.into_value_registering_obligations(self.infcx, &mut *fulfillcx);

compiler/rustc_trait_selection/src/infer.rs

@@ -3,7 +3,6 @@ use crate::traits::{self, ObligationCtxt};
 
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
-use rustc_infer::traits::ObligationCause;
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::infer::canonical::{Canonical, CanonicalizedQueryResponse, QueryResponse};
 use rustc_middle::traits::query::Fallible;
@@ -30,15 +29,6 @@ pub trait InferCtxtExt<'tcx> {
         span: Span,
     ) -> bool;
 
-    fn partially_normalize_associated_types_in<T>(
-        &self,
-        cause: ObligationCause<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-        value: T,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>;
-
     /// Check whether a `ty` implements given trait(trait_def_id).
     /// The inputs are:
     ///
@@ -88,24 +78,6 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         traits::type_known_to_meet_bound_modulo_regions(self, param_env, ty, lang_item, span)
     }
 
-    /// Normalizes associated types in `value`, potentially returning
-    /// new obligations that must further be processed.
-    #[instrument(level = "debug", skip(self, cause, param_env), ret)]
-    fn partially_normalize_associated_types_in<T>(
-        &self,
-        cause: ObligationCause<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-        value: T,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        let mut selcx = traits::SelectionContext::new(self);
-        let traits::Normalized { value, obligations } =
-            traits::normalize(&mut selcx, param_env, cause, value);
-        InferOk { value, obligations }
-    }
-
     #[instrument(level = "debug", skip(self, params), ret)]
     fn type_implements_trait(
         &self,

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -3,7 +3,7 @@ use std::fmt::Debug;
 
 use super::TraitEngine;
 use super::{ChalkFulfillmentContext, FulfillmentContext};
-use crate::infer::InferCtxtExt;
+use crate::traits::NormalizeExt;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_infer::infer::at::ToTrace;
@@ -104,11 +104,11 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
 
     pub fn normalize<T: TypeFoldable<'tcx>>(
         &self,
-        cause: ObligationCause<'tcx>,
+        cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         value: T,
     ) -> T {
-        let infer_ok = self.infcx.partially_normalize_associated_types_in(cause, param_env, value);
+        let infer_ok = self.infcx.at(&cause, param_env).normalize(value);
         self.register_infer_ok_obligations(infer_ok)
     }
 
@@ -185,7 +185,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
             // sound and then uncomment this line again.
 
             // implied_bounds.insert(ty);
-            let normalized = self.normalize(cause.clone(), param_env, ty);
+            let normalized = self.normalize(&cause, param_env, ty);
             implied_bounds.insert(normalized);
         }
         implied_bounds

compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs

@@ -17,11 +17,11 @@ pub fn recompute_applicable_impls<'tcx>(
         let placeholder_obligation =
             infcx.replace_bound_vars_with_placeholders(obligation.predicate);
         let obligation_trait_ref =
-            ocx.normalize(dummy_cause.clone(), param_env, placeholder_obligation.trait_ref);
+            ocx.normalize(&dummy_cause, param_env, placeholder_obligation.trait_ref);
 
         let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
         let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap().subst(tcx, impl_substs);
-        let impl_trait_ref = ocx.normalize(ObligationCause::dummy(), param_env, impl_trait_ref);
+        let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref);
 
         if let Err(_) = ocx.eq(&dummy_cause, param_env, obligation_trait_ref, impl_trait_ref) {
             return false;

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -9,11 +9,11 @@ use super::{
 };
 use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCode};
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
-use crate::infer::InferCtxtExt as _;
 use crate::infer::{self, InferCtxt, TyCtxtInferExt};
 use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
-use crate::traits::query::normalize::AtExt as _;
+use crate::traits::query::normalize::QueryNormalizeExt as _;
 use crate::traits::specialize::to_pretty_impl_header;
+use crate::traits::NormalizeExt;
 use on_unimplemented::OnUnimplementedNote;
 use on_unimplemented::TypeErrCtxtExt as _;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
@@ -1595,6 +1595,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     bound_predicate.rebind(data),
                 );
                 let mut obligations = vec![];
+                // FIXME(normalization): Change this to use `At::normalize`
                 let normalized_ty = super::normalize_projection_type(
                     &mut selcx,
                     obligation.param_env,
@@ -1933,7 +1934,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             let infcx = self.tcx.infer_ctxt().build();
             infcx
                 .at(&ObligationCause::dummy(), ty::ParamEnv::empty())
-                .normalize(candidate)
+                .query_normalize(candidate)
                 .map_or(candidate, |normalized| normalized.value)
         };
 
@@ -2535,11 +2536,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 pred.fold_with(&mut ParamToVarFolder { infcx: self, var_map: Default::default() });
 
             let InferOk { value: cleaned_pred, .. } =
-                self.infcx.partially_normalize_associated_types_in(
+                self.infcx.at(&ObligationCause::dummy(), param_env).normalize(cleaned_pred);
-                    ObligationCause::dummy(),
-                    param_env,
-                    cleaned_pred,
-                );
 
             let obligation =
                 Obligation::new(self.tcx, ObligationCause::dummy(), param_env, cleaned_pred);

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -2,6 +2,7 @@ use super::{DefIdOrName, Obligation, ObligationCause, ObligationCauseCode, Predi
 
 use crate::autoderef::Autoderef;
 use crate::infer::InferCtxt;
+use crate::traits::NormalizeExt;
 
 use hir::def::CtorOf;
 use hir::HirId;
@@ -2966,12 +2967,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         self.tcx.mk_substs_trait(trait_pred.self_ty(), []),
                     )
                 });
-                let InferOk { value: projection_ty, .. } = self
+                let InferOk { value: projection_ty, .. } =
-                    .partially_normalize_associated_types_in(
+                    self.at(&obligation.cause, obligation.param_env).normalize(projection_ty);
-                        obligation.cause.clone(),
-                        obligation.param_env,
-                        projection_ty,
-                    );
 
                 debug!(
                     normalized_projection_type = ?self.resolve_vars_if_possible(projection_ty)

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -56,7 +56,8 @@ pub use self::object_safety::astconv_object_safety_violations;
 pub use self::object_safety::is_vtable_safe_method;
 pub use self::object_safety::MethodViolationCode;
 pub use self::object_safety::ObjectSafetyViolation;
-pub use self::project::{normalize, normalize_projection_type, normalize_to};
+pub(crate) use self::project::{normalize, normalize_to};
+pub use self::project::{normalize_projection_type, NormalizeExt};
 pub use self::select::{EvaluationCache, SelectionCache, SelectionContext};
 pub use self::select::{EvaluationResult, IntercrateAmbiguityCause, OverflowError};
 pub use self::specialize::specialization_graph::FutureCompatOverlapError;
@@ -386,7 +387,7 @@ where
 {
     let ocx = ObligationCtxt::new(infcx);
     debug!(?value);
-    let normalized_value = ocx.normalize(cause, param_env, value);
+    let normalized_value = ocx.normalize(&cause, param_env, value);
     debug!(?normalized_value);
     debug!("select_all_or_error start");
     let errors = ocx.select_all_or_error();
@@ -453,7 +454,7 @@ pub fn impossible_predicates<'tcx>(
     let infcx = tcx.infer_ctxt().build();
     let param_env = ty::ParamEnv::reveal_all();
     let ocx = ObligationCtxt::new(&infcx);
-    let predicates = ocx.normalize(ObligationCause::dummy(), param_env, predicates);
+    let predicates = ocx.normalize(&ObligationCause::dummy(), param_env, predicates);
     for predicate in predicates {
         let obligation = Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate);
         ocx.register_obligation(obligation);

compiler/rustc_trait_selection/src/traits/project.rs

@@ -27,6 +27,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
+use rustc_infer::infer::at::At;
 use rustc_infer::infer::resolve::OpportunisticRegionResolver;
 use rustc_infer::traits::ImplSourceBuiltinData;
 use rustc_middle::traits::select::OverflowError;
@@ -48,6 +49,19 @@ pub type ProjectionTyObligation<'tcx> = Obligation<'tcx, ty::ProjectionTy<'tcx>>
 
 pub(super) struct InProgress;
 
+pub trait NormalizeExt<'tcx> {
+    fn normalize<T: TypeFoldable<'tcx>>(&self, t: T) -> InferOk<'tcx, T>;
+}
+
+impl<'tcx> NormalizeExt<'tcx> for At<'_, 'tcx> {
+    fn normalize<T: TypeFoldable<'tcx>>(&self, value: T) -> InferOk<'tcx, T> {
+        let mut selcx = SelectionContext::new(self.infcx);
+        let Normalized { value, obligations } =
+            normalize(&mut selcx, self.param_env, self.cause.clone(), value);
+        InferOk { value, obligations }
+    }
+}
+
 /// When attempting to resolve `<T as TraitRef>::Name` ...
 #[derive(Debug)]
 pub enum ProjectionError<'tcx> {
@@ -293,7 +307,7 @@ fn project_and_unify_type<'cx, 'tcx>(
 /// them with a fully resolved type where possible. The return value
 /// combines the normalized result and any additional obligations that
 /// were incurred as result.
-pub fn normalize<'a, 'b, 'tcx, T>(
+pub(crate) fn normalize<'a, 'b, 'tcx, T>(
     selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -307,7 +321,7 @@ where
     Normalized { value, obligations }
 }
 
-pub fn normalize_to<'a, 'b, 'tcx, T>(
+pub(crate) fn normalize_to<'a, 'b, 'tcx, T>(
     selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -321,7 +335,7 @@ where
 }
 
 /// As `normalize`, but with a custom depth.
-pub fn normalize_with_depth<'a, 'b, 'tcx, T>(
+pub(crate) fn normalize_with_depth<'a, 'b, 'tcx, T>(
     selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -337,7 +351,7 @@ where
 }
 
 #[instrument(level = "info", skip(selcx, param_env, cause, obligations))]
-pub fn normalize_with_depth_to<'a, 'b, 'tcx, T>(
+pub(crate) fn normalize_with_depth_to<'a, 'b, 'tcx, T>(
     selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -357,7 +371,7 @@ where
 }
 
 #[instrument(level = "info", skip(selcx, param_env, cause, obligations))]
-pub fn try_normalize_with_depth_to<'a, 'b, 'tcx, T>(
+pub(crate) fn try_normalize_with_depth_to<'a, 'b, 'tcx, T>(
     selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,

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

@@ -22,13 +22,13 @@ use super::NoSolution;
 
 pub use rustc_middle::traits::query::NormalizationResult;
 
-pub trait AtExt<'tcx> {
+pub trait QueryNormalizeExt<'tcx> {
-    fn normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
+    fn query_normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
     where
         T: TypeFoldable<'tcx>;
 }
 
-impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
+impl<'cx, 'tcx> QueryNormalizeExt<'tcx> for At<'cx, 'tcx> {
     /// Normalize `value` in the context of the inference context,
     /// yielding a resulting type, or an error if `value` cannot be
     /// normalized. If you don't care about regions, you should prefer
@@ -42,7 +42,7 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
     /// normalizing, but for now should be used only when we actually
     /// know that normalization will succeed, since error reporting
     /// and other details are still "under development".
-    fn normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
+    fn query_normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
     where
         T: TypeFoldable<'tcx>,
     {

compiler/rustc_trait_selection/src/traits/util.rs

@@ -8,8 +8,8 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
 use rustc_middle::ty::{GenericArg, SubstsRef};
 
+use super::NormalizeExt;
 use super::{Obligation, ObligationCause, PredicateObligation, SelectionContext};
-use crate::infer::InferCtxtExt;
 use rustc_infer::infer::InferOk;
 pub use rustc_infer::traits::{self, util::*};
 
@@ -202,15 +202,13 @@ pub fn impl_subject_and_oblig<'a, 'tcx>(
 ) -> (ImplSubject<'tcx>, impl Iterator<Item = PredicateObligation<'tcx>>) {
     let subject = selcx.tcx().bound_impl_subject(impl_def_id);
     let subject = subject.subst(selcx.tcx(), impl_substs);
-    let InferOk { value: subject, obligations: normalization_obligations1 } = selcx
+    let InferOk { value: subject, obligations: normalization_obligations1 } =
-        .infcx
+        selcx.infcx.at(&ObligationCause::dummy(), param_env).normalize(subject);
-        .partially_normalize_associated_types_in(ObligationCause::dummy(), param_env, subject);
 
     let predicates = selcx.tcx().predicates_of(impl_def_id);
     let predicates = predicates.instantiate(selcx.tcx(), impl_substs);
-    let InferOk { value: predicates, obligations: normalization_obligations2 } = selcx
+    let InferOk { value: predicates, obligations: normalization_obligations2 } =
-        .infcx
+        selcx.infcx.at(&ObligationCause::dummy(), param_env).normalize(predicates);
-        .partially_normalize_associated_types_in(ObligationCause::dummy(), param_env, predicates);
     let impl_obligations =
         super::predicates_for_generics(|_, _| ObligationCause::dummy(), param_env, predicates);
 

compiler/rustc_traits/src/dropck_outlives.rs

@@ -11,7 +11,7 @@ use rustc_trait_selection::traits::query::dropck_outlives::trivial_dropck_outliv
 use rustc_trait_selection::traits::query::dropck_outlives::{
     DropckConstraint, DropckOutlivesResult,
 };
-use rustc_trait_selection::traits::query::normalize::AtExt;
+use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use rustc_trait_selection::traits::query::{CanonicalTyGoal, NoSolution};
 use rustc_trait_selection::traits::{Normalized, ObligationCause};
 
@@ -100,7 +100,7 @@ fn dropck_outlives<'tcx>(
             // to push them onto the stack to be expanded.
             for ty in constraints.dtorck_types.drain(..) {
                 let Normalized { value: ty, obligations } =
-                    ocx.infcx.at(&cause, param_env).normalize(ty)?;
+                    ocx.infcx.at(&cause, param_env).query_normalize(ty)?;
                 ocx.register_obligations(obligations);
 
                 debug!("dropck_outlives: ty from dtorck_types = {:?}", ty);

compiler/rustc_traits/src/normalize_erasing_regions.rs

@@ -2,7 +2,7 @@ use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, ParamEnvAnd, TyCtxt, TypeFoldable};
-use rustc_trait_selection::traits::query::normalize::AtExt;
+use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use rustc_trait_selection::traits::{Normalized, ObligationCause};
 use std::sync::atomic::Ordering;
 
@@ -29,7 +29,7 @@ fn try_normalize_after_erasing_regions<'tcx, T: TypeFoldable<'tcx> + PartialEq +
     let ParamEnvAnd { param_env, value } = goal;
     let infcx = tcx.infer_ctxt().build();
     let cause = ObligationCause::dummy();
-    match infcx.at(&cause, param_env).normalize(value) {
+    match infcx.at(&cause, param_env).query_normalize(value) {
         Ok(Normalized { value: normalized_value, obligations: normalized_obligations }) => {
             // We don't care about the `obligations`; they are
             // always only region relations, and we are about to

compiler/rustc_traits/src/type_op.rs

@@ -8,7 +8,7 @@ use rustc_middle::ty::{ParamEnvAnd, Predicate, ToPredicate};
 use rustc_middle::ty::{UserSelfTy, UserSubsts};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
-use rustc_trait_selection::traits::query::normalize::AtExt;
+use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use rustc_trait_selection::traits::query::type_op::ascribe_user_type::AscribeUserType;
 use rustc_trait_selection::traits::query::type_op::eq::Eq;
 use rustc_trait_selection::traits::query::type_op::normalize::Normalize;
@@ -62,7 +62,7 @@ pub fn type_op_ascribe_user_type_with_span<'tcx>(
     let cause = ObligationCause::dummy_with_span(span);
 
     let ty = tcx.bound_type_of(def_id).subst(tcx, substs);
-    let ty = ocx.normalize(cause.clone(), param_env, ty);
+    let ty = ocx.normalize(&cause, param_env, ty);
     debug!("relate_type_and_user_type: ty of def-id is {:?}", ty);
 
     ocx.eq(&cause, param_env, mir_ty, ty)?;
@@ -85,14 +85,14 @@ pub fn type_op_ascribe_user_type_with_span<'tcx>(
             ObligationCauseCode::AscribeUserTypeProvePredicate(predicate_span),
         );
         let instantiated_predicate =
-            ocx.normalize(cause.clone(), param_env, instantiated_predicate);
+            ocx.normalize(&cause.clone(), param_env, instantiated_predicate);
 
         ocx.register_obligation(Obligation::new(tcx, cause, param_env, instantiated_predicate));
     }
 
     if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
         let impl_self_ty = tcx.bound_type_of(impl_def_id).subst(tcx, substs);
-        let impl_self_ty = ocx.normalize(cause.clone(), param_env, impl_self_ty);
+        let impl_self_ty = ocx.normalize(&cause, param_env, impl_self_ty);
 
         ocx.eq(&cause, param_env, self_ty, impl_self_ty)?;
 
@@ -137,7 +137,7 @@ where
 {
     let (param_env, Normalize { value }) = key.into_parts();
     let Normalized { value, obligations } =
-        ocx.infcx.at(&ObligationCause::dummy(), param_env).normalize(value)?;
+        ocx.infcx.at(&ObligationCause::dummy(), param_env).query_normalize(value)?;
     ocx.register_obligations(obligations);
     Ok(value)
 }

src/librustdoc/clean/mod.rs

@@ -1581,14 +1581,14 @@ fn normalize<'tcx>(cx: &mut DocContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>>
     }
 
     use crate::rustc_trait_selection::infer::TyCtxtInferExt;
-    use crate::rustc_trait_selection::traits::query::normalize::AtExt;
+    use crate::rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
     use rustc_middle::traits::ObligationCause;
 
     // Try to normalize `<X as Y>::T` to a type
     let infcx = cx.tcx.infer_ctxt().build();
     let normalized = infcx
         .at(&ObligationCause::dummy(), cx.param_env)
-        .normalize(ty)
+        .query_normalize(ty)
         .map(|resolved| infcx.resolve_vars_if_possible(resolved.value));
     match normalized {
         Ok(normalized_value) => {

src/tools/clippy/clippy_utils/src/ty.rs

@@ -22,7 +22,7 @@ use rustc_span::symbol::Ident;
 use rustc_span::{sym, Span, Symbol, DUMMY_SP};
 use rustc_target::abi::{Size, VariantIdx};
 use rustc_trait_selection::infer::InferCtxtExt;
-use rustc_trait_selection::traits::query::normalize::AtExt;
+use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use std::iter;
 
 use crate::{match_def_path, path_res, paths};
@@ -283,7 +283,7 @@ fn is_normalizable_helper<'tcx>(
     cache.insert(ty, false);
     let infcx = cx.tcx.infer_ctxt().build();
     let cause = rustc_middle::traits::ObligationCause::dummy();
-    let result = if infcx.at(&cause, param_env).normalize(ty).is_ok() {
+    let result = if infcx.at(&cause, param_env).query_normalize(ty).is_ok() {
         match ty.kind() {
             ty::Adt(def, substs) => def.variants().iter().all(|variant| {
                 variant