Move MatchAgainstFreshVars to old solver

compiler/rustc_infer/src/infer/relate/mod.rs

@@ -4,11 +4,9 @@
 
 pub use rustc_middle::ty::relate::*;
 
-pub use self::_match::MatchAgainstFreshVars;
 pub use self::combine::CombineFields;
 pub use self::combine::PredicateEmittingRelation;
 
-pub mod _match;
 pub(super) mod combine;
 mod generalize;
 mod glb;

compiler/rustc_trait_selection/src/traits/select/_match.rs

@@ -1,10 +1,10 @@
+use rustc_infer::infer::relate::{
+    self, structurally_relate_tys, Relate, RelateResult, TypeRelation,
+};
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, InferConst, Ty, TyCtxt};
 use tracing::{debug, instrument};
 
-use super::{structurally_relate_tys, Relate, RelateResult, TypeRelation};
-use crate::infer::relate;
-
 /// A type "A" *matches* "B" if the fresh types in B could be
 /// instantiated with values so as to make it equal to A. Matching is
 /// intended to be used only on freshened types, and it basically

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -32,7 +32,6 @@ use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{Diag, EmissionGuarantee};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::relate::MatchAgainstFreshVars;
 use rustc_infer::infer::relate::TypeRelation;
 use rustc_infer::infer::BoundRegionConversionTime;
 use rustc_infer::infer::BoundRegionConversionTime::HigherRankedType;
@@ -60,6 +59,7 @@ use std::ops::ControlFlow;
 pub use rustc_middle::traits::select::*;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 
+mod _match;
 mod candidate_assembly;
 mod confirmation;
 
@@ -2719,7 +2719,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
         previous: ty::PolyTraitPredicate<'tcx>,
         current: ty::PolyTraitPredicate<'tcx>,
     ) -> bool {
-        let mut matcher = MatchAgainstFreshVars::new(self.tcx());
+        let mut matcher = _match::MatchAgainstFreshVars::new(self.tcx());
         matcher.relate(previous, current).is_ok()
     }