Remove tag field from Relations

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

@@ -110,7 +110,7 @@ impl<'tcx> MatchAgainstHigherRankedOutlives<'tcx> {
 
     /// Binds the pattern variable `br` to `value`; returns an `Err` if the pattern
     /// is already bound to a different value.
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn bind(
         &mut self,
         br: ty::BoundRegion,
@@ -133,10 +133,6 @@ impl<'tcx> MatchAgainstHigherRankedOutlives<'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx> {
-    fn tag(&self) -> &'static str {
-        "MatchAgainstHigherRankedOutlives"
-    }
-
     fn cx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
@@ -154,13 +150,12 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx>
         if variance != ty::Bivariant { self.relate(a, b) } else { Ok(a) }
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn regions(
         &mut self,
         pattern: ty::Region<'tcx>,
         value: ty::Region<'tcx>,
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
-        debug!("self.pattern_depth = {:?}", self.pattern_depth);
         if let ty::RegionKind::ReBound(depth, br) = pattern.kind()
             && depth == self.pattern_depth
         {
@@ -172,7 +167,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx>
         }
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn tys(&mut self, pattern: Ty<'tcx>, value: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         // FIXME(non_lifetime_binders): What to do here?
         if matches!(pattern.kind(), ty::Error(_) | ty::Bound(..)) {
@@ -185,20 +180,20 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx>
         }
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn consts(
         &mut self,
         pattern: ty::Const<'tcx>,
         value: ty::Const<'tcx>,
     ) -> RelateResult<'tcx, ty::Const<'tcx>> {
-        debug!("{}.consts({:?}, {:?})", self.tag(), pattern, value);
         if pattern == value {
             Ok(pattern)
         } else {
             relate::structurally_relate_consts(self, pattern, value)
         }
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn binders<T>(
         &mut self,
         pattern: ty::Binder<'tcx, T>,

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

@@ -79,6 +79,7 @@ impl<'tcx> InferCtxt<'tcx> {
     where
         R: PredicateEmittingRelation<InferCtxt<'tcx>>,
     {
+        debug!("super_combine_tys::<{}>({:?}, {:?})", std::any::type_name::<R>(), a, b);
         debug_assert!(!a.has_escaping_bound_vars());
         debug_assert!(!b.has_escaping_bound_vars());
 
@@ -174,9 +175,10 @@ impl<'tcx> InferCtxt<'tcx> {
     where
         R: PredicateEmittingRelation<InferCtxt<'tcx>>,
     {
-        debug!("{}.consts({:?}, {:?})", relation.tag(), a, b);
+        debug!("super_combine_consts::<{}>({:?}, {:?})", std::any::type_name::<R>(), a, b);
         debug_assert!(!a.has_escaping_bound_vars());
         debug_assert!(!b.has_escaping_bound_vars());
+
         if a == b {
             return Ok(a);
         }

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 cx(&self) -> TyCtxt<'tcx> {
         self.fields.tcx()
     }
@@ -47,17 +43,17 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Glb<'_, '_, 'tcx> {
         }
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         lattice::super_lattice_tys(self, a, b)
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn regions(
         &mut self,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
-        debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
-
         let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
         // GLB(&'static u8, &'a u8) == &RegionLUB('static, 'a) u8 == &'static u8
         Ok(self.fields.infcx.inner.borrow_mut().unwrap_region_constraints().lub_regions(
@@ -68,6 +64,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Glb<'_, '_, 'tcx> {
         ))
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn consts(
         &mut self,
         a: ty::Const<'tcx>,

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

@@ -56,8 +56,6 @@ pub fn super_lattice_tys<'a, 'tcx: 'a, L>(
 where
     L: LatticeDir<'a, 'tcx>,
 {
-    debug!("{}", this.tag());
-
     if a == b {
         return Ok(a);
     }

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 cx(&self) -> TyCtxt<'tcx> {
         self.fields.tcx()
     }
@@ -51,13 +47,12 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Lub<'_, '_, 'tcx> {
         lattice::super_lattice_tys(self, a, b)
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn regions(
         &mut self,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
-        debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
-
         let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
         // LUB(&'static u8, &'a u8) == &RegionGLB('static, 'a) u8 == &'a u8
         Ok(self.fields.infcx.inner.borrow_mut().unwrap_region_constraints().glb_regions(
@@ -68,6 +63,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Lub<'_, '_, 'tcx> {
         ))
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn consts(
         &mut self,
         a: ty::Const<'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 cx(&self) -> TyCtxt<'tcx> {
         self.fields.infcx.tcx
     }
@@ -71,7 +67,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
         r
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         if a == b {
             return Ok(a);
@@ -166,12 +162,12 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
         Ok(a)
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn regions(
         &mut self,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
-        debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
         let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
 
         match self.ambient_variance {
@@ -209,6 +205,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
         Ok(a)
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn consts(
         &mut self,
         a: ty::Const<'tcx>,

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

@@ -3,7 +3,7 @@ use rustc_infer::infer::relate::{
 };
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, InferConst, Ty, TyCtxt};
-use tracing::{debug, instrument};
+use tracing::instrument;
 
 /// 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
@@ -32,10 +32,6 @@ impl<'tcx> MatchAgainstFreshVars<'tcx> {
 }
 
 impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
-    fn tag(&self) -> &'static str {
-        "MatchAgainstFreshVars"
-    }
-
     fn cx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
@@ -50,7 +46,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
         self.relate(a, b)
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn regions(
         &mut self,
         a: ty::Region<'tcx>,
@@ -59,7 +55,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
         Ok(a)
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "trace")]
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         if a == b {
             return Ok(a);
@@ -83,12 +79,12 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstFreshVars<'tcx> {
         }
     }
 
+    #[instrument(skip(self), level = "trace")]
     fn consts(
         &mut self,
         a: ty::Const<'tcx>,
         b: ty::Const<'tcx>,
     ) -> RelateResult<'tcx, ty::Const<'tcx>> {
-        debug!("{}.consts({:?}, {:?})", self.tag(), a, b);
         if a == b {
             return Ok(a);
         }

compiler/rustc_type_ir/src/relate.rs

@@ -1,7 +1,7 @@
 use std::iter;
 
 use rustc_ast_ir::Mutability;
-use tracing::{debug, instrument};
+use tracing::{instrument, trace};
 
 use crate::error::{ExpectedFound, TypeError};
 use crate::fold::TypeFoldable;
@@ -58,9 +58,6 @@ impl<I: Interner> VarianceDiagInfo<I> {
 pub trait TypeRelation<I: Interner>: Sized {
     fn cx(&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)
@@ -69,17 +66,13 @@ pub trait TypeRelation<I: Interner>: Sized {
     /// Relate the two args for the given item. The default
     /// is to look up the variance for the item and proceed
     /// accordingly.
+    #[instrument(skip(self), level = "trace")]
     fn relate_item_args(
         &mut self,
         item_def_id: I::DefId,
         a_arg: I::GenericArgs,
         b_arg: I::GenericArgs,
     ) -> RelateResult<I, I::GenericArgs> {
-        debug!(
-            "relate_item_args(item_def_id={:?}, a_arg={:?}, b_arg={:?})",
-            item_def_id, a_arg, b_arg
-        );
-
         let cx = self.cx();
         let opt_variances = cx.variances_of(item_def_id);
         relate_args_with_variances(self, item_def_id, opt_variances, a_arg, b_arg, true)
@@ -571,15 +564,25 @@ 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);
+    trace!(
+        "structurally_relate_consts::<{}>(a = {:?}, b = {:?})",
+        std::any::type_name::<R>(),
+        a,
+        b
+    );
     let cx = relation.cx();
 
     if cx.features().generic_const_exprs() {
         a = cx.expand_abstract_consts(a);
         b = cx.expand_abstract_consts(b);
     }
 
-    debug!("{}.structurally_relate_consts(normed_a = {:?}, normed_b = {:?})", relation.tag(), a, b);
+    trace!(
+        "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