Rollup merge of #141638 - oli-obk:builtin-index, r=lcnr

Use `builtin_index` instead of hand-rolling it

Just using the dedicated method more

3 files changed, 6 insertions, 13 deletions

diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 063dbbcaecb..f85ff5a6f4b 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -1046,8 +1046,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) -> Result<(),
                             match ty.kind() {
                                 ty::Adt(adt_def, ..) => adt_def.did().is_local(),
                                 // Arrays and slices use the inner type's `ConstParamTy`.
-                                ty::Array(ty, ..) => ty_is_local(*ty),
-                                ty::Slice(ty) => ty_is_local(*ty),
+                                ty::Array(ty, ..) | ty::Slice(ty) => ty_is_local(*ty),
                                 // `&` references use the inner type's `ConstParamTy`.
                                 // `&mut` are not supported.
                                 ty::Ref(_, ty, ast::Mutability::Not) => ty_is_local(*ty),
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 1d86f7d223c..082ddac7e5a 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1793,10 +1793,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let element_ty = if !args.is_empty() {
             let coerce_to = expected
                 .to_option(self)
-                .and_then(|uty| match *self.try_structurally_resolve_type(expr.span, uty).kind() {
-                    ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
-                    _ => None,
-                })
+                .and_then(|uty| self.try_structurally_resolve_type(expr.span, uty).builtin_index())
                 .unwrap_or_else(|| self.next_ty_var(expr.span));
             let mut coerce = CoerceMany::with_coercion_sites(coerce_to, args);
             assert_eq!(self.diverges.get(), Diverges::Maybe);
@@ -1874,10 +1871,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         let uty = match expected {
-            ExpectHasType(uty) => match *uty.kind() {
-                ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
-                _ => None,
-            },
+            ExpectHasType(uty) => uty.builtin_index(),
             _ => None,
         };
 
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index d9f1888bfd9..46ced7500ea 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -249,12 +249,12 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                 ty::Ref(_, rty, _) => reveal_and_alloc(cx, once(*rty)),
                 _ => bug!("Unexpected type for `Ref` constructor: {ty:?}"),
             },
-            Slice(slice) => match *ty.kind() {
-                ty::Slice(ty) | ty::Array(ty, _) => {
+            Slice(slice) => match ty.builtin_index() {
+                Some(ty) => {
                     let arity = slice.arity();
                     reveal_and_alloc(cx, (0..arity).map(|_| ty))
                 }
-                _ => bug!("bad slice pattern {:?} {:?}", ctor, ty),
+                None => bug!("bad slice pattern {:?} {:?}", ctor, ty),
             },
             DerefPattern(pointee_ty) => reveal_and_alloc(cx, once(pointee_ty.inner())),
             Bool(..) | IntRange(..) | F16Range(..) | F32Range(..) | F64Range(..)