Rollup merge of #110531 - lcnr:type-system-stuff, r=aliemjay

small type system cleanup

Author: matthiaskrgr

compiler/rustc_middle/src/ty/flags.rs

@@ -178,7 +178,7 @@ impl FlagComputation {
 
             &ty::Alias(ty::Projection, data) => {
                 self.add_flags(TypeFlags::HAS_TY_PROJECTION);
-                self.add_projection_ty(data);
+                self.add_alias_ty(data);
             }
 
             &ty::Alias(ty::Opaque, ty::AliasTy { substs, .. }) => {
@@ -267,7 +267,7 @@ impl FlagComputation {
                 projection_ty,
                 term,
             })) => {
-                self.add_projection_ty(projection_ty);
+                self.add_alias_ty(projection_ty);
                 self.add_term(term);
             }
             ty::PredicateKind::WellFormed(arg) => {
@@ -372,8 +372,8 @@ impl FlagComputation {
         }
     }
 
-    fn add_projection_ty(&mut self, projection_ty: ty::AliasTy<'_>) {
-        self.add_substs(projection_ty.substs);
+    fn add_alias_ty(&mut self, alias_ty: ty::AliasTy<'_>) {
+        self.add_substs(alias_ty.substs);
     }
 
     fn add_substs(&mut self, substs: &[GenericArg<'_>]) {

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -170,29 +170,20 @@ pub fn predicate_obligations<'tcx>(
         ty::PredicateKind::WellFormed(arg) => {
             wf.compute(arg);
         }
-        ty::PredicateKind::ObjectSafe(_) => {}
-        ty::PredicateKind::ClosureKind(..) => {}
-        ty::PredicateKind::Subtype(ty::SubtypePredicate { a, b, a_is_expected: _ }) => {
-            wf.compute(a.into());
-            wf.compute(b.into());
-        }
-        ty::PredicateKind::Coerce(ty::CoercePredicate { a, b }) => {
-            wf.compute(a.into());
-            wf.compute(b.into());
-        }
+
         ty::PredicateKind::ConstEvaluatable(ct) => {
             wf.compute(ct.into());
         }
-        ty::PredicateKind::ConstEquate(c1, c2) => {
-            wf.compute(c1.into());
-            wf.compute(c2.into());
-        }
-        ty::PredicateKind::Ambiguous => {}
-        ty::PredicateKind::TypeWellFormedFromEnv(..) => {
-            bug!("TypeWellFormedFromEnv is only used for Chalk")
-        }
-        ty::PredicateKind::AliasRelate(..) => {
-            bug!("We should only wf check where clauses and `AliasRelate` is not a `Clause`")
+
+        ty::PredicateKind::ObjectSafe(_)
+        | ty::PredicateKind::ClosureKind(..)
+        | ty::PredicateKind::Subtype(..)
+        | ty::PredicateKind::Coerce(..)
+        | ty::PredicateKind::ConstEquate(..)
+        | ty::PredicateKind::Ambiguous
+        | ty::PredicateKind::AliasRelate(..)
+        | ty::PredicateKind::TypeWellFormedFromEnv(..) => {
+            bug!("We should only wf check where clauses, unexpected predicate: {predicate:?}")
         }
     }