Rollup merge of #146313 - nnethercote:rustc_middle-ty-cleanups-2, r=lcnr

Some `rustc_middle` cleanups

Minor improvements I found while looking through this code.

r? `@BoxyUwU`

5 files changed, 13 insertions, 82 deletions

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 874cee54c7c..8fba218cc71 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -135,7 +135,7 @@ use crate::traits::{
 };
 use crate::ty::fast_reject::SimplifiedType;
 use crate::ty::layout::ValidityRequirement;
-use crate::ty::print::{PrintTraitRefExt, describe_as_module};
+use crate::ty::print::PrintTraitRefExt;
 use crate::ty::util::AlwaysRequiresDrop;
 use crate::ty::{
     self, CrateInherentImpls, GenericArg, GenericArgsRef, PseudoCanonicalInput, SizedTraitKind, Ty,
@@ -2731,3 +2731,12 @@ rustc_queries! {
 
 rustc_with_all_queries! { define_callbacks! }
 rustc_feedable_queries! { define_feedable! }
+
+fn describe_as_module(def_id: impl Into<LocalDefId>, tcx: TyCtxt<'_>) -> String {
+    let def_id = def_id.into();
+    if def_id.is_top_level_module() {
+        "top-level module".to_string()
+    } else {
+        format!("module `{}`", tcx.def_path_str(def_id))
+    }
+}
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index e567ba05f61..da17ec1f9f3 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -109,7 +109,6 @@ pub use self::typeck_results::{
     CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, IsIdentity,
     Rust2024IncompatiblePatInfo, TypeckResults, UserType, UserTypeAnnotationIndex, UserTypeKind,
 };
-pub use self::visit::*;
 use crate::error::{OpaqueHiddenTypeMismatch, TypeMismatchReason};
 use crate::metadata::ModChild;
 use crate::middle::privacy::EffectiveVisibilities;
diff --git a/compiler/rustc_middle/src/ty/predicate.rs b/compiler/rustc_middle/src/ty/predicate.rs
index 59e00f85957..69dcca54f46 100644
--- a/compiler/rustc_middle/src/ty/predicate.rs
+++ b/compiler/rustc_middle/src/ty/predicate.rs
@@ -638,21 +638,7 @@ impl<'tcx> Predicate<'tcx> {
         let predicate = self.kind();
         match predicate.skip_binder() {
             PredicateKind::Clause(ClauseKind::Trait(t)) => Some(predicate.rebind(t)),
-            PredicateKind::Clause(ClauseKind::Projection(..))
-            | PredicateKind::Clause(ClauseKind::HostEffect(..))
-            | PredicateKind::Clause(ClauseKind::ConstArgHasType(..))
-            | PredicateKind::Clause(ClauseKind::UnstableFeature(_))
-            | PredicateKind::NormalizesTo(..)
-            | PredicateKind::AliasRelate(..)
-            | PredicateKind::Subtype(..)
-            | PredicateKind::Coerce(..)
-            | PredicateKind::Clause(ClauseKind::RegionOutlives(..))
-            | PredicateKind::Clause(ClauseKind::WellFormed(..))
-            | PredicateKind::DynCompatible(..)
-            | PredicateKind::Clause(ClauseKind::TypeOutlives(..))
-            | PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
-            | PredicateKind::ConstEquate(..)
-            | PredicateKind::Ambiguous => None,
+            _ => None,
         }
     }
 
@@ -660,21 +646,7 @@ impl<'tcx> Predicate<'tcx> {
         let predicate = self.kind();
         match predicate.skip_binder() {
             PredicateKind::Clause(ClauseKind::Projection(t)) => Some(predicate.rebind(t)),
-            PredicateKind::Clause(ClauseKind::Trait(..))
-            | PredicateKind::Clause(ClauseKind::HostEffect(..))
-            | PredicateKind::Clause(ClauseKind::ConstArgHasType(..))
-            | PredicateKind::Clause(ClauseKind::UnstableFeature(_))
-            | PredicateKind::NormalizesTo(..)
-            | PredicateKind::AliasRelate(..)
-            | PredicateKind::Subtype(..)
-            | PredicateKind::Coerce(..)
-            | PredicateKind::Clause(ClauseKind::RegionOutlives(..))
-            | PredicateKind::Clause(ClauseKind::WellFormed(..))
-            | PredicateKind::DynCompatible(..)
-            | PredicateKind::Clause(ClauseKind::TypeOutlives(..))
-            | PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
-            | PredicateKind::ConstEquate(..)
-            | PredicateKind::Ambiguous => None,
+            _ => None,
         }
     }
 
diff --git a/compiler/rustc_middle/src/ty/print/mod.rs b/compiler/rustc_middle/src/ty/print/mod.rs
index 9e6f277ef77..d636e8ef31f 100644
--- a/compiler/rustc_middle/src/ty/print/mod.rs
+++ b/compiler/rustc_middle/src/ty/print/mod.rs
@@ -2,7 +2,7 @@ use hir::def::Namespace;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sso::SsoHashSet;
 use rustc_hir as hir;
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
+use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use tracing::{debug, instrument, trace};
 
@@ -396,16 +396,6 @@ impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::Const<'tcx> {
     }
 }
 
-// This is only used by query descriptions
-pub fn describe_as_module(def_id: impl Into<LocalDefId>, tcx: TyCtxt<'_>) -> String {
-    let def_id = def_id.into();
-    if def_id.is_top_level_module() {
-        "top-level module".to_string()
-    } else {
-        format!("module `{}`", tcx.def_path_str(def_id))
-    }
-}
-
 impl<T> rustc_type_ir::ir_print::IrPrint<T> for TyCtxt<'_>
 where
     T: Copy + for<'a, 'tcx> Lift<TyCtxt<'tcx>, Lifted: Print<'tcx, FmtPrinter<'a, 'tcx>>>,
diff --git a/compiler/rustc_middle/src/ty/visit.rs b/compiler/rustc_middle/src/ty/visit.rs
index 3853a804a92..f0c47f257cc 100644
--- a/compiler/rustc_middle/src/ty/visit.rs
+++ b/compiler/rustc_middle/src/ty/visit.rs
@@ -212,42 +212,3 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for LateBoundRegionsCollector {
         }
     }
 }
-
-/// Finds the max universe present
-pub struct MaxUniverse {
-    max_universe: ty::UniverseIndex,
-}
-
-impl MaxUniverse {
-    pub fn new() -> Self {
-        MaxUniverse { max_universe: ty::UniverseIndex::ROOT }
-    }
-
-    pub fn max_universe(self) -> ty::UniverseIndex {
-        self.max_universe
-    }
-}
-
-impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxUniverse {
-    fn visit_ty(&mut self, t: Ty<'tcx>) {
-        if let ty::Placeholder(placeholder) = t.kind() {
-            self.max_universe = self.max_universe.max(placeholder.universe);
-        }
-
-        t.super_visit_with(self)
-    }
-
-    fn visit_const(&mut self, c: ty::consts::Const<'tcx>) {
-        if let ty::ConstKind::Placeholder(placeholder) = c.kind() {
-            self.max_universe = self.max_universe.max(placeholder.universe);
-        }
-
-        c.super_visit_with(self)
-    }
-
-    fn visit_region(&mut self, r: ty::Region<'tcx>) {
-        if let ty::RePlaceholder(placeholder) = r.kind() {
-            self.max_universe = self.max_universe.max(placeholder.universe);
-        }
-    }
-}