Address some more nits

compiler/rustc_hir_analysis/src/check/compare_method.rs

@@ -290,10 +290,7 @@ fn compare_predicate_entailment<'tcx>(
     // type would be more appropriate. In other places we have a `Vec<Span>`
     // corresponding to their `Vec<Predicate>`, but we don't have that here.
     // Fixing this would improve the output of test `issue-83765.rs`.
-    let mut result = infcx
-        .at(&cause, param_env)
-        .sup(trait_fty, impl_fty)
-        .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok));
+    let mut result = ocx.sup_types(&cause, param_env, trait_fty, impl_fty);
 
     // HACK(RPITIT): #101614. When we are trying to infer the hidden types for
     // RPITITs, we need to equate the output tys instead of just subtyping. If
@@ -302,10 +299,7 @@ fn compare_predicate_entailment<'tcx>(
     // fixed up to `ReEmpty`, and which is certainly not what we want.
     if trait_fty.has_infer_types() {
         result = result.and_then(|()| {
-            infcx
-                .at(&cause, param_env)
-                .eq(trait_sig.output(), impl_sig.output())
-                .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok))
+            ocx.equate_types(&cause, param_env, trait_sig.output(), impl_sig.output())
         });
     }
 
@@ -1389,10 +1383,7 @@ pub(crate) fn raw_compare_const_impl<'tcx>(
 
     debug!("compare_const_impl: trait_ty={:?}", trait_ty);
 
-    let err = infcx
-        .at(&cause, param_env)
-        .sup(trait_ty, impl_ty)
-        .map(|ok| ocx.register_infer_ok_obligations(ok));
+    let err = ocx.sup_types(&cause, param_env, trait_ty, impl_ty);
 
     if let Err(terr) = err {
         debug!(

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -6,6 +6,7 @@ use super::{ChalkFulfillmentContext, FulfillmentContext};
 use crate::infer::InferCtxtExt;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_infer::infer::at::ToTrace;
 use rustc_infer::infer::canonical::{
     Canonical, CanonicalVarValues, CanonicalizedQueryResponse, QueryResponse,
 };
@@ -111,12 +112,12 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
         self.register_infer_ok_obligations(infer_ok)
     }
 
-    pub fn equate_types(
+    pub fn equate_types<T: ToTrace<'tcx>>(
         &self,
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-        expected: Ty<'tcx>,
-        actual: Ty<'tcx>,
+        expected: T,
+        actual: T,
     ) -> Result<(), TypeError<'tcx>> {
         match self.infcx.at(cause, param_env).eq(expected, actual) {
             Ok(InferOk { obligations, value: () }) => {
@@ -127,6 +128,22 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
         }
     }
 
+    pub fn sup_types<T: ToTrace<'tcx>>(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        expected: T,
+        actual: T,
+    ) -> Result<(), TypeError<'tcx>> {
+        match self.infcx.at(cause, param_env).sup(expected, actual) {
+            Ok(InferOk { obligations, value: () }) => {
+                self.register_obligations(obligations);
+                Ok(())
+            }
+            Err(e) => Err(e),
+        }
+    }
+
     pub fn select_all_or_error(&self) -> Vec<FulfillmentError<'tcx>> {
         self.engine.borrow_mut().select_all_or_error(self.infcx)
     }

compiler/rustc_traits/src/type_op.rs

@@ -87,12 +87,7 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
     where
         T: ToTrace<'tcx>,
     {
-        Ok(self.ocx.register_infer_ok_obligations(
-            self.ocx
-                .infcx
-                .at(&ObligationCause::dummy_with_span(self.span), self.param_env)
-                .eq(a, b)?,
-        ))
+        Ok(self.ocx.equate_types(&ObligationCause::dummy_with_span(self.span), self.param_env, a, b)?)
     }
 
     fn prove_predicate(&self, predicate: Predicate<'tcx>, cause: ObligationCause<'tcx>) {
@@ -181,10 +176,7 @@ fn type_op_eq<'tcx>(
 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
     tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |ocx, key| {
         let (param_env, Eq { a, b }) = key.into_parts();
-        ocx.register_infer_ok_obligations(
-            ocx.infcx.at(&ObligationCause::dummy(), param_env).eq(a, b)?,
-        );
-        Ok(())
+        Ok(ocx.equate_types(&ObligationCause::dummy(), param_env, a, b)?)
     })
 }
 
@@ -236,10 +228,7 @@ fn type_op_subtype<'tcx>(
 ) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, ()>>, NoSolution> {
     tcx.infer_ctxt().enter_canonical_trait_query(&canonicalized, |ocx, key| {
         let (param_env, Subtype { sub, sup }) = key.into_parts();
-        ocx.register_infer_ok_obligations(
-            ocx.infcx.at(&ObligationCause::dummy(), param_env).sup(sup, sub)?,
-        );
-        Ok(())
+        Ok(ocx.sup_types(&ObligationCause::dummy(), param_env, sup, sub)?)
     })
 }