use ocx type relation routines

Author: lcnr

compiler/rustc_const_eval/src/util/compare_types.rs

@@ -48,10 +48,10 @@ pub fn is_subtype<'tcx>(
     let cause = ObligationCause::dummy();
     let src = ocx.normalize(cause.clone(), param_env, src);
     let dest = ocx.normalize(cause.clone(), param_env, dest);
-    let Ok(infer_ok) = infcx.at(&cause, param_env).sub(src, dest) else {
-        return false;
+    match ocx.sub(&cause, param_env, src, dest) {
+        Ok(()) => {}
+        Err(_) => return false,
     };
-    let () = ocx.register_infer_ok_obligations(infer_ok);
     let errors = ocx.select_all_or_error();
     // With `Reveal::All`, opaque types get normalized away, with `Reveal::UserFacing`
     // we would get unification errors because we're unable to look into opaque types,

compiler/rustc_hir_analysis/src/check/check.rs

@@ -451,8 +451,8 @@ fn check_opaque_meets_bounds<'tcx>(
 
     let misc_cause = traits::ObligationCause::misc(span, hir_id);
 
-    match infcx.at(&misc_cause, param_env).eq(opaque_ty, hidden_ty) {
-        Ok(infer_ok) => ocx.register_infer_ok_obligations(infer_ok),
+    match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) {
+        Ok(()) => {}
         Err(ty_err) => {
             tcx.sess.delay_span_bug(
                 span,

compiler/rustc_hir_analysis/src/check/compare_method.rs

@@ -402,10 +402,8 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
         unnormalized_trait_sig.inputs_and_output.iter().chain(trait_sig.inputs_and_output.iter()),
     );
 
-    match infcx.at(&cause, param_env).eq(trait_return_ty, impl_return_ty) {
-        Ok(infer::InferOk { value: (), obligations }) => {
-            ocx.register_obligations(obligations);
-        }
+    match ocx.eq(&cause, param_env, trait_return_ty, impl_return_ty) {
+        Ok(()) => {}
         Err(terr) => {
             let mut diag = struct_span_err!(
                 tcx.sess,
@@ -442,10 +440,8 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
     // the lifetimes of the return type, but do this after unifying just the
     // return types, since we want to avoid duplicating errors from
     // `compare_predicate_entailment`.
-    match infcx.at(&cause, param_env).eq(trait_fty, impl_fty) {
-        Ok(infer::InferOk { value: (), obligations }) => {
-            ocx.register_obligations(obligations);
-        }
+    match ocx.eq(&cause, param_env, trait_fty, impl_fty) {
+        Ok(()) => {}
         Err(terr) => {
             // This function gets called during `compare_predicate_entailment` when normalizing a
             // signature that contains RPITIT. When the method signatures don't match, we have to

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -125,20 +125,32 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
             .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
     }
 
+    /// Checks whether `expected` is a subtype of `actual`: `expected <: actual`.
+    pub fn sub<T: ToTrace<'tcx>>(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        expected: T,
+        actual: T,
+    ) -> Result<(), TypeError<'tcx>> {
+        self.infcx
+            .at(cause, param_env)
+            .sup(expected, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
+    }
+
+    /// Checks whether `expected` is a supertype of `actual`: `expected :> actual`.
     pub fn sup<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),
-        }
+        self.infcx
+            .at(cause, param_env)
+            .sup(expected, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
     }
 
     pub fn select_where_possible(&self) -> Vec<FulfillmentError<'tcx>> {