Consolidate the 'match assumption' type methods in GoalKind

3 files changed, 47 insertions, 140 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 0f42d5f1262..25cc82f01d5 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -99,6 +99,17 @@ pub(super) trait GoalKind<'tcx>:
 
     fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId;
 
+    // Try equating an assumption predicate against a goal's predicate. If it
+    // holds, then execute the `then` callback, which should do any additional
+    // work, then produce a response (typically by executing
+    // [`EvalCtxt::evaluate_added_goals_and_make_canonical_response`]).
+    fn probe_and_match_goal_against_assumption(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        assumption: ty::Predicate<'tcx>,
+        then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,
+    ) -> QueryResult<'tcx>;
+
     // Consider a clause, which consists of a "assumption" and some "requirements",
     // to satisfy a goal. If the requirements hold, then attempt to satisfy our
     // goal by equating it with the assumption.
@@ -107,7 +118,12 @@ pub(super) trait GoalKind<'tcx>:
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
         requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>,
-    ) -> QueryResult<'tcx>;
+    ) -> QueryResult<'tcx> {
+        Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| {
+            ecx.add_goals(requirements);
+            ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+        })
+    }
 
     /// Consider a bound originating from the item bounds of an alias. For this we
     /// require that the well-formed requirements of the self type of the goal
@@ -117,7 +133,11 @@ pub(super) trait GoalKind<'tcx>:
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx>;
+    ) -> QueryResult<'tcx> {
+        Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| {
+            ecx.validate_alias_bound_self_from_param_env(goal)
+        })
+    }
 
     // Consider a clause specifically for a `dyn Trait` self type. This requires
     // additionally checking all of the supertraits and object bounds to hold,
@@ -126,7 +146,25 @@ pub(super) trait GoalKind<'tcx>:
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx>;
+    ) -> QueryResult<'tcx> {
+        Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| {
+            let tcx = ecx.tcx();
+            let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else {
+                    bug!("expected object type in `consider_object_bound_candidate`");
+                };
+            ecx.add_goals(
+                structural_traits::predicates_for_object_candidate(
+                    &ecx,
+                    goal.param_env,
+                    goal.predicate.trait_ref(tcx),
+                    bounds,
+                )
+                .into_iter()
+                .map(|pred| goal.with(tcx, pred)),
+            );
+            ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+        })
+    }
 
     fn consider_impl_candidate(
         ecx: &mut EvalCtxt<'_, 'tcx>,
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index 85ac7f15a2f..20ce2d9416e 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -56,11 +56,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
         self.trait_def_id(tcx)
     }
 
-    fn consider_implied_clause(
+    fn probe_and_match_goal_against_assumption(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
-        requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>,
+        then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,
     ) -> QueryResult<'tcx> {
         if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred()
             && poly_projection_pred.projection_def_id() == goal.predicate.def_id()
@@ -75,73 +75,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 )?;
                 ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)
                     .expect("expected goal term to be fully unconstrained");
-                ecx.add_goals(requirements);
-                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
-            })
-        } else {
-            Err(NoSolution)
-        }
-    }
-
-    fn consider_alias_bound_candidate(
-        ecx: &mut EvalCtxt<'_, 'tcx>,
-        goal: Goal<'tcx, Self>,
-        assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx> {
-        if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred()
-            && poly_projection_pred.projection_def_id() == goal.predicate.def_id()
-        {
-            ecx.probe(|ecx| {
-                let assumption_projection_pred =
-                    ecx.instantiate_binder_with_infer(poly_projection_pred);
-                ecx.eq(
-                    goal.param_env,
-                    goal.predicate.projection_ty,
-                    assumption_projection_pred.projection_ty,
-                )?;
-                ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)?;
-                ecx.validate_alias_bound_self_from_param_env(goal)
-            })
-        } else {
-            Err(NoSolution)
-        }
-    }
-
-    fn consider_object_bound_candidate(
-        ecx: &mut EvalCtxt<'_, 'tcx>,
-        goal: Goal<'tcx, Self>,
-        assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx> {
-        if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred()
-            && poly_projection_pred.projection_def_id() == goal.predicate.def_id()
-        {
-            ecx.probe(|ecx| {
-                let tcx = ecx.tcx();
-
-                let assumption_projection_pred =
-                    ecx.instantiate_binder_with_infer(poly_projection_pred);
-                ecx.eq(
-                    goal.param_env,
-                    goal.predicate.projection_ty,
-                    assumption_projection_pred.projection_ty,
-                )?;
-
-                let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else {
-                    bug!("expected object type in `consider_object_bound_candidate`");
-                };
-                ecx.add_goals(
-                    structural_traits::predicates_for_object_candidate(
-                        &ecx,
-                        goal.param_env,
-                        goal.predicate.projection_ty.trait_ref(tcx),
-                        bounds,
-                    )
-                    .into_iter()
-                    .map(|pred| goal.with(tcx, pred)),
-                );
-                ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)
-                    .expect("expected goal term to be fully unconstrained");
-                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+                then(ecx)
             })
         } else {
             Err(NoSolution)
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index 0f6fd4059b4..dcfa33ae842 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -78,11 +78,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
         })
     }
 
-    fn consider_implied_clause(
+    fn probe_and_match_goal_against_assumption(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
-        requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>,
+        then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,
     ) -> QueryResult<'tcx> {
         if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred()
             && poly_trait_pred.def_id() == goal.predicate.def_id()
@@ -97,72 +97,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
                     goal.predicate.trait_ref,
                     assumption_trait_pred.trait_ref,
                 )?;
-                ecx.add_goals(requirements);
-                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
-            })
-        } else {
-            Err(NoSolution)
-        }
-    }
-
-    fn consider_alias_bound_candidate(
-        ecx: &mut EvalCtxt<'_, 'tcx>,
-        goal: Goal<'tcx, Self>,
-        assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx> {
-        if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred()
-            && poly_trait_pred.def_id() == goal.predicate.def_id()
-        {
-            // FIXME: Constness and polarity
-            ecx.probe(|ecx| {
-                let assumption_trait_pred =
-                    ecx.instantiate_binder_with_infer(poly_trait_pred);
-                ecx.eq(
-                    goal.param_env,
-                    goal.predicate.trait_ref,
-                    assumption_trait_pred.trait_ref,
-                )?;
-                ecx.validate_alias_bound_self_from_param_env(goal)
-            })
-        } else {
-            Err(NoSolution)
-        }
-    }
-
-    fn consider_object_bound_candidate(
-        ecx: &mut EvalCtxt<'_, 'tcx>,
-        goal: Goal<'tcx, Self>,
-        assumption: ty::Predicate<'tcx>,
-    ) -> QueryResult<'tcx> {
-        if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred()
-            && poly_trait_pred.def_id() == goal.predicate.def_id()
-            && poly_trait_pred.polarity() == goal.predicate.polarity
-        {
-            // FIXME: Constness and polarity
-            ecx.probe(|ecx| {
-                let assumption_trait_pred =
-                    ecx.instantiate_binder_with_infer(poly_trait_pred);
-                ecx.eq(
-                    goal.param_env,
-                    goal.predicate.trait_ref,
-                    assumption_trait_pred.trait_ref,
-                )?;
-
-                let tcx = ecx.tcx();
-                let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else {
-                    bug!("expected object type in `consider_object_bound_candidate`");
-                };
-                ecx.add_goals(
-                    structural_traits::predicates_for_object_candidate(
-                        &ecx,
-                        goal.param_env,
-                        goal.predicate.trait_ref,
-                        bounds,
-                    )
-                    .into_iter()
-                    .map(|pred| goal.with(tcx, pred)),
-                );
-                ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+                then(ecx)
             })
         } else {
             Err(NoSolution)