Auto merge of #118937 - lcnr:rename-solver-flag, r=compiler-errors

`-Ztrait-solver=next` to `-Znext-solver`

renames the feature flag to enable the new trait solver.

still want some feedback before merging: https://rust-lang.zulipchat.com/#narrow/stream/364551-t-types.2Ftrait-system-refactor/topic/renaming.20the.20feature.20flag.20to.20.60-Znew-solver.60.

The idea is to make it easier to add another option, e.g. to enable the solver in wfcheck or to optionally change its behavior to our new coinduction approach.

r? `@compiler-errors`

20 files changed, 62 insertions, 64 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
index b3e7a63c972..cafb858794a 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
@@ -200,9 +200,10 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         let result = f(&mut ecx);
 
         let tree = ecx.inspect.finalize();
-        if let (Some(tree), DumpSolverProofTree::Always) =
-            (&tree, infcx.tcx.sess.opts.unstable_opts.dump_solver_proof_tree)
-        {
+        if let (Some(tree), DumpSolverProofTree::Always) = (
+            &tree,
+            infcx.tcx.sess.opts.unstable_opts.next_solver.map(|c| c.dump_tree).unwrap_or_default(),
+        ) {
             let mut lock = std::io::stdout().lock();
             let _ = lock.write_fmt(format_args!("{tree:?}\n"));
             let _ = lock.flush();
@@ -377,7 +378,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         //
         // This assert was removed as it did not hold for goals constraining
         // an inference variable to a recursive alias, e.g. in
-        // tests/ui/traits/new-solver/overflow/recursive-self-normalization.rs.
+        // tests/ui/traits/next-solver/overflow/recursive-self-normalization.rs.
         //
         // Once we have decided on how to handle trait-system-refactor-initiative#75,
         // we should re-add an assert here.
@@ -421,7 +422,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                     self.compute_const_evaluatable_goal(Goal { param_env, predicate: ct })
                 }
                 ty::PredicateKind::ConstEquate(_, _) => {
-                    bug!("ConstEquate should not be emitted when `-Ztrait-solver=next` is active")
+                    bug!("ConstEquate should not be emitted when `-Znext-solver` is active")
                 }
                 ty::PredicateKind::NormalizesTo(predicate) => {
                     self.compute_normalizes_to_goal(Goal { param_env, predicate })
diff --git a/compiler/rustc_trait_selection/src/solve/inspect/build.rs b/compiler/rustc_trait_selection/src/solve/inspect/build.rs
index 0d46df44c91..c857aae572d 100644
--- a/compiler/rustc_trait_selection/src/solve/inspect/build.rs
+++ b/compiler/rustc_trait_selection/src/solve/inspect/build.rs
@@ -265,7 +265,7 @@ impl<'tcx> ProofTreeBuilder<'tcx> {
             GenerateProofTree::Never => ProofTreeBuilder::new_noop(),
             GenerateProofTree::IfEnabled => {
                 let opts = &tcx.sess.opts.unstable_opts;
-                match opts.dump_solver_proof_tree {
+                match opts.next_solver.map(|c| c.dump_tree).unwrap_or_default() {
                     DumpSolverProofTree::Always => ProofTreeBuilder::new_root(),
                     // `OnError` is handled by reevaluating goals in error
                     // reporting with `GenerateProofTree::Yes`.
diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs
index f45473e06dc..1e58106e353 100644
--- a/compiler/rustc_trait_selection/src/solve/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/mod.rs
@@ -1,7 +1,6 @@
 //! The next-generation trait solver, currently still WIP.
 //!
-//! As a user of rust, you can use `-Ztrait-solver=next` or `next-coherence`
-//! to enable the new trait solver always, or just within coherence, respectively.
+//! As a user of rust, you can use `-Znext-solver` to enable the new trait solver.
 //!
 //! As a developer of rustc, you shouldn't be using the new trait
 //! solver without asking the trait-system-refactor-initiative, but it can
@@ -248,7 +247,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             return None;
         }
 
-        // FIXME(-Ztrait-solver=next): We should instead try to find a `Certainty::Yes` response with
+        // FIXME(-Znext-solver): We should instead try to find a `Certainty::Yes` response with
         // a subset of the constraints that all the other responses have.
         let one = responses[0];
         if responses[1..].iter().all(|&resp| resp == one) {
diff --git a/compiler/rustc_trait_selection/src/solve/search_graph.rs b/compiler/rustc_trait_selection/src/solve/search_graph.rs
index 71adebffc15..2a08b80e02a 100644
--- a/compiler/rustc_trait_selection/src/solve/search_graph.rs
+++ b/compiler/rustc_trait_selection/src/solve/search_graph.rs
@@ -38,7 +38,7 @@ struct StackEntry<'tcx> {
     /// If we were to use that result when later trying to prove another cycle
     /// participant, we can end up with unstable query results.
     ///
-    /// See tests/ui/new-solver/coinduction/incompleteness-unstable-result.rs for
+    /// See tests/ui/next-solver/coinduction/incompleteness-unstable-result.rs for
     /// an example of where this is needed.
     cycle_participants: FxHashSet<CanonicalInput<'tcx>>,
 }
@@ -237,7 +237,7 @@ impl<'tcx> SearchGraph<'tcx> {
                     // in unstable results due to incompleteness.
                     //
                     // However, a test for this would be an even more complex version of
-                    // tests/ui/traits/new-solver/coinduction/incompleteness-unstable-result.rs.
+                    // tests/ui/traits/next-solver/coinduction/incompleteness-unstable-result.rs.
                     // I did not bother to write such a test and we have no regression test
                     // for this. It would be good to have such a test :)
                     #[allow(rustc::potential_query_instability)]
@@ -248,7 +248,7 @@ impl<'tcx> SearchGraph<'tcx> {
                 // until we reach a fixpoint. It is not enough to simply retry the
                 // `root` goal of this cycle.
                 //
-                // See tests/ui/traits/new-solver/cycles/fixpoint-rerun-all-cycle-heads.rs
+                // See tests/ui/traits/next-solver/cycles/fixpoint-rerun-all-cycle-heads.rs
                 // for an example.
                 self.stack[stack_depth].has_been_used = true;
                 return if let Some(result) = self.stack[stack_depth].provisional_result {
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index 5807f7c6153..9536fde7c93 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -445,7 +445,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
             return Err(NoSolution);
         }
 
-        // FIXME(-Ztrait-solver=next): Implement this when we get const working in the new solver
+        // FIXME(-Znext-solver): Implement this when we get const working in the new solver
 
         // `Destruct` is automatically implemented for every type in
         // non-const environments.
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index db4d4a93e54..88ebea70021 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -855,7 +855,7 @@ where
     }
 
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-        // Need to lazily normalize here in with `-Ztrait-solver=next-coherence`.
+        // Need to lazily normalize here in with `-Znext-solver=coherence`.
         let ty = match (self.lazily_normalize_ty)(ty) {
             Ok(ty) => ty,
             Err(err) => return ControlFlow::Break(OrphanCheckEarlyExit::NormalizationFailure(err)),
@@ -1069,7 +1069,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> {
                 let lazily_normalize_ty = |ty: Ty<'tcx>| {
                     let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(infcx);
                     if matches!(ty.kind(), ty::Alias(..)) {
-                        // FIXME(-Ztrait-solver=next-coherence): we currently don't
+                        // FIXME(-Znext-solver=coherence): we currently don't
                         // normalize opaque types here, resulting in diverging behavior
                         // for TAITs.
                         match infcx
diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index 67718d0a348..013a50f9fa1 100644
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -25,7 +25,6 @@ use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::TypeFoldable;
 use rustc_middle::ty::Variance;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_session::config::TraitSolver;
 
 pub trait TraitEngineExt<'tcx> {
     fn new(infcx: &InferCtxt<'tcx>) -> Box<Self>;
@@ -33,18 +32,16 @@ pub trait TraitEngineExt<'tcx> {
 
 impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> {
     fn new(infcx: &InferCtxt<'tcx>) -> Box<Self> {
-        match (infcx.tcx.sess.opts.unstable_opts.trait_solver, infcx.next_trait_solver()) {
-            (TraitSolver::Classic, false) | (TraitSolver::NextCoherence, false) => {
-                Box::new(FulfillmentContext::new(infcx))
-            }
-            (TraitSolver::Classic | TraitSolver::Next | TraitSolver::NextCoherence, true) => {
-                Box::new(NextFulfillmentCtxt::new(infcx))
-            }
-            (TraitSolver::Next, false) => bug!(
-                "incompatible combination of -Ztrait-solver flag ({:?}) and InferCtxt::next_trait_solver ({:?})",
-                infcx.tcx.sess.opts.unstable_opts.trait_solver,
-                infcx.next_trait_solver()
-            ),
+        if infcx.next_trait_solver() {
+            Box::new(NextFulfillmentCtxt::new(infcx))
+        } else {
+            let new_solver_globally =
+                infcx.tcx.sess.opts.unstable_opts.next_solver.map_or(false, |c| c.globally);
+            assert!(
+                !new_solver_globally,
+                "using old solver even though new solver is enabled globally"
+            );
+            Box::new(FulfillmentContext::new(infcx))
         }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
index 7f6e48f4464..b3bb0a9fcb7 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
@@ -37,7 +37,7 @@ use rustc_middle::ty::{
     self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
     TypeVisitable, TypeVisitableExt,
 };
-use rustc_session::config::{DumpSolverProofTree, TraitSolver};
+use rustc_session::config::DumpSolverProofTree;
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
 use rustc_span::symbol::sym;
@@ -370,7 +370,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) {
         let tcx = self.tcx;
 
-        if tcx.sess.opts.unstable_opts.dump_solver_proof_tree == DumpSolverProofTree::OnError {
+        if tcx.sess.opts.unstable_opts.next_solver.map(|c| c.dump_tree).unwrap_or_default()
+            == DumpSolverProofTree::OnError
+        {
             dump_proof_tree(root_obligation, self.infcx);
         }
 
@@ -812,23 +814,20 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
                     ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(ty)) => {
                         let ty = self.resolve_vars_if_possible(ty);
-                        match self.tcx.sess.opts.unstable_opts.trait_solver {
-                            TraitSolver::Classic => {
-                                // WF predicates cannot themselves make
-                                // errors. They can only block due to
-                                // ambiguity; otherwise, they always
-                                // degenerate into other obligations
-                                // (which may fail).
-                                span_bug!(span, "WF predicate not satisfied for {:?}", ty);
-                            }
-                            TraitSolver::Next | TraitSolver::NextCoherence => {
-                                // FIXME: we'll need a better message which takes into account
-                                // which bounds actually failed to hold.
-                                self.tcx.sess.struct_span_err(
-                                    span,
-                                    format!("the type `{ty}` is not well-formed"),
-                                )
-                            }
+                        if self.next_trait_solver() {
+                            // FIXME: we'll need a better message which takes into account
+                            // which bounds actually failed to hold.
+                            self.tcx.sess.struct_span_err(
+                                span,
+                                format!("the type `{ty}` is not well-formed"),
+                            )
+                        } else {
+                            // WF predicates cannot themselves make
+                            // errors. They can only block due to
+                            // ambiguity; otherwise, they always
+                            // degenerate into other obligations
+                            // (which may fail).
+                            span_bug!(span, "WF predicate not satisfied for {:?}", ty);
                         }
                     }
 
@@ -1562,7 +1561,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
     #[instrument(skip(self), level = "debug")]
     fn report_fulfillment_error(&self, error: &FulfillmentError<'tcx>) {
-        if self.tcx.sess.opts.unstable_opts.dump_solver_proof_tree == DumpSolverProofTree::OnError {
+        if self.tcx.sess.opts.unstable_opts.next_solver.map(|c| c.dump_tree).unwrap_or_default()
+            == DumpSolverProofTree::OnError
+        {
             dump_proof_tree(&error.root_obligation, self.infcx);
         }
 
@@ -1668,7 +1669,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     )
                     .into(),
                 };
-                // FIXME(-Ztrait-solver=next): For diagnostic purposes, it would be nice
+                // FIXME(-Znext-solver): For diagnostic purposes, it would be nice
                 // to deeply normalize this type.
                 let normalized_term =
                     ocx.normalize(&obligation.cause, obligation.param_env, unnormalized_term);
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 64d2b5fc159..8c5f1e90715 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -315,7 +315,7 @@ pub fn normalize_param_env_or_error<'tcx>(
             // We do not normalize types here as there is no backwards compatibility requirement
             // for us to do so.
             //
-            // FIXME(-Ztrait-solver=next): remove this hack since we have deferred projection equality
+            // FIXME(-Znext-solver): remove this hack since we have deferred projection equality
             predicate.fold_with(&mut ConstNormalizer(tcx))
         }),
     )
@@ -386,7 +386,7 @@ pub fn normalize_param_env_or_error<'tcx>(
 
 /// Normalize a type and process all resulting obligations, returning any errors.
 ///
-/// FIXME(-Ztrait-solver=next): This should be replaced by `At::deeply_normalize`
+/// FIXME(-Znext-solver): This should be replaced by `At::deeply_normalize`
 /// which has the same behavior with the new solver. Because using a separate
 /// fulfillment context worsens caching in the old solver, `At::deeply_normalize`
 /// is still lazy with the old solver as it otherwise negatively impacts perf.
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index a08e35b566f..4c3eb05819f 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -67,7 +67,7 @@ pub trait NormalizeExt<'tcx> {
     /// same goals in both a temporary and the shared context which negatively impacts
     /// performance as these don't share caching.
     ///
-    /// FIXME(-Ztrait-solver=next): This has the same behavior as `traits::fully_normalize`
+    /// FIXME(-Znext-solver): This has the same behavior as `traits::fully_normalize`
     /// in the new solver, but because of performance reasons, we currently reuse an
     /// existing fulfillment context in the old solver. Once we also eagerly prove goals with
     /// the old solver or have removed the old solver, remove `traits::fully_normalize` and
diff --git a/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs b/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs
index 04b3119323f..d812d537d8c 100644
--- a/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs
@@ -72,7 +72,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
                 let mut fulfill_cx = crate::solve::FulfillmentCtxt::new(self);
                 fulfill_cx.register_predicate_obligation(self, obligation.clone());
                 // True errors
-                // FIXME(-Ztrait-solver=next): Overflows are reported as ambig here, is that OK?
+                // FIXME(-Znext-solver): Overflows are reported as ambig here, is that OK?
                 if !fulfill_cx.select_where_possible(self).is_empty() {
                     Ok(EvaluationResult::EvaluatedToErr)
                 } else if !fulfill_cx.select_all_or_error(self).is_empty() {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs
index 302b6016e5e..152ceeee869 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs
@@ -26,7 +26,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for AscribeUserType<'tcx> {
         tcx.type_op_ascribe_user_type(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs
index f6589308806..57e649f3e43 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs
@@ -23,7 +23,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for Eq<'tcx> {
         tcx.type_op_eq(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
index f9b8ea32d89..10528696b2d 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
@@ -50,7 +50,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
         tcx.implied_outlives_bounds(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
index cd09aaff2d9..272f1a54f81 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
@@ -89,7 +89,7 @@ pub trait QueryTypeOp<'tcx>: fmt::Debug + Copy + TypeFoldable<TyCtxt<'tcx>> + 't
     /// make sure to feed it predefined opaque types and the defining anchor
     /// and that would require duplicating all of the tcx queries. Instead,
     /// just perform these ops locally.
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution>;
@@ -149,7 +149,7 @@ where
         if infcx.next_trait_solver() {
             return Ok(scrape_region_constraints(
                 infcx,
-                |ocx| QueryTypeOp::perform_locally_in_new_solver(ocx, self),
+                |ocx| QueryTypeOp::perform_locally_with_next_solver(ocx, self),
                 "query type op",
                 span,
             )?
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs
index 9559f5002f6..3b33f6e6144 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs
@@ -25,11 +25,11 @@ where
         T::type_op_method(tcx, canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
-        // FIXME(-Ztrait-solver=next): shouldn't be using old normalizer
+        // FIXME(-Znext-solver): shouldn't be using old normalizer
         Ok(ocx.normalize(&ObligationCause::dummy(), key.param_env, key.value.value))
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
index f2c1243f931..07587e37411 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
@@ -42,7 +42,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for DropckOutlives<'tcx> {
         tcx.dropck_outlives(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs
index 789ef647246..e21ede47f6d 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs
@@ -40,7 +40,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> {
         tcx.type_op_prove_predicate(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs
index 10976d5cd71..ae11b0825bd 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs
@@ -20,7 +20,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for Subtype<'tcx> {
         tcx.type_op_subtype(canonicalized)
     }
 
-    fn perform_locally_in_new_solver(
+    fn perform_locally_with_next_solver(
         ocx: &ObligationCtxt<'_, 'tcx>,
         key: ParamEnvAnd<'tcx, Self>,
     ) -> Result<Self::QueryResponse, NoSolution> {
diff --git a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
index 32de8feda81..b9ab26fe2fe 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
@@ -22,7 +22,7 @@ impl<'tcx> StructurallyNormalizeExt<'tcx> for At<'_, 'tcx> {
         assert!(!ty.is_ty_var(), "should have resolved vars before calling");
 
         if self.infcx.next_trait_solver() {
-            // FIXME(-Ztrait-solver=next): correctly handle
+            // FIXME(-Znext-solver): correctly handle
             // overflow here.
             for _ in 0..256 {
                 let ty::Alias(ty::Projection | ty::Inherent | ty::Weak, alias) = *ty.kind() else {