Auto merge of rust-lang#126514 - matthiaskrgr:rollup-pnwi8ns, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#126354 (Use `Variance` glob imported variants everywhere)
 - rust-lang#126367 (Point out failing never obligation for `DEPENDENCY_ON_UNIT_NEVER_TYPE_FALLBACK`)
 - rust-lang#126469 (MIR Shl/Shr: the offset can be computed with rem_euclid)
 - rust-lang#126471 (Use a consistent way to filter out bounds instead of splitting it into three places)
 - rust-lang#126472 (build `libcxx-version` only when it doesn't exist)
 - rust-lang#126497 (delegation: Fix hygiene for `self`)
 - rust-lang#126501 (make bors ignore comments in PR template)
 - rust-lang#126509 (std: suggest OnceLock over Once)
 - rust-lang#126512 (Miri subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

.github/pull_request_template.md

@@ -1,3 +1,4 @@
+<!-- homu-ignore:start -->
 <!--
 If this PR is related to an unstable feature or an otherwise tracked effort,
 please link to the relevant tracking issue here. If you don't know of a related
@@ -7,4 +8,5 @@ This PR will get automatically assigned to a reviewer. In case you would like
 a specific user to review your work, you can assign it to them by using
 
     r​? <reviewer name>
--->
+-->
+<!-- homu-ignore:end -->

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -328,7 +328,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
         if let Some(annotation_index) = constant.user_ty {
             if let Err(terr) = self.cx.relate_type_and_user_type(
                 constant.const_.ty(),
-                ty::Variance::Invariant,
+                ty::Invariant,
                 &UserTypeProjection { base: annotation_index, projs: vec![] },
                 locations,
                 ConstraintCategory::Boring,
@@ -451,7 +451,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
 
                 if let Err(terr) = self.cx.relate_type_and_user_type(
                     ty,
-                    ty::Variance::Invariant,
+                    ty::Invariant,
                     user_ty,
                     Locations::All(*span),
                     ConstraintCategory::TypeAnnotation,
@@ -1095,7 +1095,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     ) -> Result<(), NoSolution> {
         // Use this order of parameters because the sup type is usually the
         // "expected" type in diagnostics.
-        self.relate_types(sup, ty::Variance::Contravariant, sub, locations, category)
+        self.relate_types(sup, ty::Contravariant, sub, locations, category)
     }
 
     #[instrument(skip(self, category), level = "debug")]
@@ -1106,7 +1106,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         locations: Locations,
         category: ConstraintCategory<'tcx>,
     ) -> Result<(), NoSolution> {
-        self.relate_types(expected, ty::Variance::Invariant, found, locations, category)
+        self.relate_types(expected, ty::Invariant, found, locations, category)
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -1146,7 +1146,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         trace!(?curr_projected_ty);
 
         let ty = curr_projected_ty.ty;
-        self.relate_types(ty, v.xform(ty::Variance::Contravariant), a, locations, category)?;
+        self.relate_types(ty, v.xform(ty::Contravariant), a, locations, category)?;
 
         Ok(())
     }
@@ -1248,7 +1248,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 if let Some(annotation_index) = self.rvalue_user_ty(rv) {
                     if let Err(terr) = self.relate_type_and_user_type(
                         rv_ty,
-                        ty::Variance::Invariant,
+                        ty::Invariant,
                         &UserTypeProjection { base: annotation_index, projs: vec![] },
                         location.to_locations(),
                         ConstraintCategory::Boring,