Remove tag field from relations

Author: compiler-errors

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -313,10 +313,6 @@ impl<'bccx, 'tcx> TypeRelation<TyCtxt<'tcx>> for NllTypeRelating<'_, 'bccx, 'tcx
         self.type_checker.infcx.tcx
     }
 
-    fn tag(&self) -> &'static str {
-        "nll::subtype"
-    }
-
     #[instrument(skip(self, info), level = "trace", ret)]
     fn relate_with_variance<T: Relate<TyCtxt<'tcx>>>(
         &mut self,

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

@@ -1934,10 +1934,6 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for SameTypeModuloInfer<'_, 'tcx> {
         self.0.tcx
     }
 
-    fn tag(&self) -> &'static str {
-        "SameTypeModuloInfer"
-    }
-
     fn relate_with_variance<T: relate::Relate<TyCtxt<'tcx>>>(
         &mut self,
         _variance: ty::Variance,

compiler/rustc_infer/src/infer/outlives/test_type_match.rs

@@ -133,10 +133,6 @@ impl<'tcx> MatchAgainstHigherRankedOutlives<'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx> {
-    fn tag(&self) -> &'static str {
-        "MatchAgainstHigherRankedOutlives"
-    }
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }

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

@@ -401,10 +401,6 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Generalizer<'_, 'tcx> {
         self.infcx.tcx
     }
 
-    fn tag(&self) -> &'static str {
-        "Generalizer"
-    }
-
     fn relate_item_args(
         &mut self,
         item_def_id: DefId,

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

@@ -23,10 +23,6 @@ impl<'combine, 'infcx, 'tcx> Glb<'combine, 'infcx, 'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Glb<'_, '_, 'tcx> {
-    fn tag(&self) -> &'static str {
-        "Glb"
-    }
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.fields.tcx()
     }

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

@@ -23,10 +23,6 @@ impl<'combine, 'infcx, 'tcx> Lub<'combine, 'infcx, 'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Lub<'_, '_, 'tcx> {
-    fn tag(&self) -> &'static str {
-        "Lub"
-    }
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.fields.tcx()
     }

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

@@ -28,10 +28,6 @@ impl<'combine, 'infcx, 'tcx> TypeRelating<'combine, 'infcx, 'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
-    fn tag(&self) -> &'static str {
-        "TypeRelating"
-    }
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.fields.infcx.tcx
     }

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

@@ -32,10 +32,6 @@ impl<'tcx> MatchAgainstFreshVars<'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
-    fn tag(&self) -> &'static str {
-        "MatchAgainstFreshVars"
-    }
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }

compiler/rustc_type_ir/src/relate.rs

@@ -58,9 +58,6 @@ impl<I: Interner> VarianceDiagInfo<I> {
 pub trait TypeRelation<I: Interner>: Sized {
     fn tcx(&self) -> I;
 
-    /// Returns a static string we can use for printouts.
-    fn tag(&self) -> &'static str;
-
     /// Generic relation routine suitable for most anything.
     fn relate<T: Relate<I>>(&mut self, a: T, b: T) -> RelateResult<I, T> {
         Relate::relate(self, a, b)
@@ -572,15 +569,20 @@ pub fn structurally_relate_consts<I: Interner, R: TypeRelation<I>>(
     mut a: I::Const,
     mut b: I::Const,
 ) -> RelateResult<I, I::Const> {
-    debug!("{}.structurally_relate_consts(a = {:?}, b = {:?})", relation.tag(), a, b);
+    debug!("{}.structurally_relate_consts(a = {:?}, b = {:?})", std::any::type_name::<R>(), a, b);
     let tcx = relation.tcx();
 
     if tcx.features().generic_const_exprs() {
         a = tcx.expand_abstract_consts(a);
         b = tcx.expand_abstract_consts(b);
     }
 
-    debug!("{}.structurally_relate_consts(normed_a = {:?}, normed_b = {:?})", relation.tag(), a, b);
+    debug!(
+        "{}.structurally_relate_consts(normed_a = {:?}, normed_b = {:?})",
+        std::any::type_name::<R>(),
+        a,
+        b
+    );
 
     // Currently, the values that can be unified are primitive types,
     // and those that derive both `PartialEq` and `Eq`, corresponding