Rollup merge of #126353 - compiler-errors:move-match, r=lcnr

Move `MatchAgainstFreshVars` to old solver

Small change I noticed when trying to uplift the relations to the new trait solver.

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()
     }