From dd981989726b297d46573ab5a03a661a31927c83 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 23 May 2023 00:56:24 +0000
Subject: [PATCH] Match on both reveal and solver mode at the same time

---
 .../src/solve/opaques.rs                      | 79 +++++++++----------
 1 file changed, 38 insertions(+), 41 deletions(-)

diff --git a/compiler/rustc_trait_selection/src/solve/opaques.rs b/compiler/rustc_trait_selection/src/solve/opaques.rs
index 54557aeb9a2..a5de4ddee82 100644
--- a/compiler/rustc_trait_selection/src/solve/opaques.rs
+++ b/compiler/rustc_trait_selection/src/solve/opaques.rs
@@ -15,51 +15,48 @@ pub(super) fn normalize_opaque_type(
         let opaque_ty = goal.predicate.projection_ty;
         let expected = goal.predicate.term.ty().expect("no such thing as an opaque const");
 
-        match goal.param_env.reveal() {
-            Reveal::UserFacing => match self.solver_mode() {
-                SolverMode::Normal => {
-                    let Some(opaque_ty_def_id) = opaque_ty.def_id.as_local() else {
-                        return Err(NoSolution);
-                    };
-                    let opaque_ty =
-                        ty::OpaqueTypeKey { def_id: opaque_ty_def_id, substs: opaque_ty.substs };
-                    // FIXME: at some point we should call queries without defining
-                    // new opaque types but having the existing opaque type definitions.
-                    // This will require moving this below "Prefer opaques registered already".
-                    if !self.can_define_opaque_ty(opaque_ty_def_id) {
+        match (goal.param_env.reveal(), self.solver_mode()) {
+            (Reveal::UserFacing, SolverMode::Normal) => {
+                let Some(opaque_ty_def_id) = opaque_ty.def_id.as_local() else {
+                    return Err(NoSolution);
+                };
+                let opaque_ty =
+                    ty::OpaqueTypeKey { def_id: opaque_ty_def_id, substs: opaque_ty.substs };
+                // FIXME: at some point we should call queries without defining
+                // new opaque types but having the existing opaque type definitions.
+                // This will require moving this below "Prefer opaques registered already".
+                if !self.can_define_opaque_ty(opaque_ty_def_id) {
+                    return Err(NoSolution);
+                }
+                // FIXME: This may have issues when the substs contain aliases...
+                match self.tcx().uses_unique_placeholders_ignoring_regions(opaque_ty.substs) {
+                    Err(NotUniqueParam::NotParam(param)) if param.is_non_region_infer() => {
+                        return self.evaluate_added_goals_and_make_canonical_response(
+                            Certainty::AMBIGUOUS,
+                        );
+                    }
+                    Err(_) => {
                         return Err(NoSolution);
                     }
-                    // FIXME: This may have issues when the substs contain aliases...
-                    match self.tcx().uses_unique_placeholders_ignoring_regions(opaque_ty.substs) {
-                        Err(NotUniqueParam::NotParam(param)) if param.is_non_region_infer() => {
-                            return self.evaluate_added_goals_and_make_canonical_response(
-                                Certainty::AMBIGUOUS,
-                            );
-                        }
-                        Err(_) => {
-                            return Err(NoSolution);
-                        }
-                        Ok(()) => {}
-                    }
-                    // Prefer opaques registered already.
-                    let matches =
-                        self.unify_existing_opaque_tys(goal.param_env, opaque_ty, expected);
-                    if !matches.is_empty() {
-                        if let Some(response) = self.try_merge_responses(&matches) {
-                            return Ok(response);
-                        } else {
-                            return self.flounder(&matches);
-                        }
-                    }
-                    // Otherwise, define a new opaque type
-                    self.register_opaque_ty(opaque_ty, expected, goal.param_env)?;
-                    self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+                    Ok(()) => {}
                 }
-                SolverMode::Coherence => {
-                    self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
+                // Prefer opaques registered already.
+                let matches = self.unify_existing_opaque_tys(goal.param_env, opaque_ty, expected);
+                if !matches.is_empty() {
+                    if let Some(response) = self.try_merge_responses(&matches) {
+                        return Ok(response);
+                    } else {
+                        return self.flounder(&matches);
+                    }
                 }
-            },
-            Reveal::All => {
+                // Otherwise, define a new opaque type
+                self.register_opaque_ty(opaque_ty, expected, goal.param_env)?;
+                self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+            }
+            (Reveal::UserFacing, SolverMode::Coherence) => {
+                self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
+            }
+            (Reveal::All, _) => {
                 // FIXME: Add an assertion that opaque type storage is empty.
                 let actual = tcx.type_of(opaque_ty.def_id).subst(tcx, opaque_ty.substs);
                 self.eq(goal.param_env, expected, actual)?;