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

Use `builtin_index` instead of hand-rolling it

Just using the dedicated method more

Author: jhpratt

clippy_lints/src/index_refutable_slice.rs

@@ -12,7 +12,6 @@ use rustc_hir::HirId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::ty;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_span::symbol::Ident;
@@ -109,11 +108,11 @@ fn find_slice_values(cx: &LateContext<'_>, pat: &hir::Pat<'_>) -> FxIndexMap<Hir
             }
 
             let bound_ty = cx.typeck_results().node_type(pat.hir_id);
-            if let ty::Slice(inner_ty) | ty::Array(inner_ty, _) = bound_ty.peel_refs().kind() {
+            if let Some(inner_ty) = bound_ty.peel_refs().builtin_index() {
                 // The values need to use the `ref` keyword if they can't be copied.
                 // This will need to be adjusted if the lint want to support mutable access in the future
                 let src_is_ref = bound_ty.is_ref() && by_ref == hir::ByRef::No;
-                let needs_ref = !(src_is_ref || is_copy(cx, *inner_ty));
+                let needs_ref = !(src_is_ref || is_copy(cx, inner_ty));
 
                 let slice_info = slices
                     .entry(value_hir_id)

clippy_lints/src/tuple_array_conversions.rs

@@ -66,7 +66,7 @@ impl LateLintPass<'_> for TupleArrayConversions {
 }
 
 fn check_array<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, elements: &'tcx [Expr<'tcx>]) {
-    let (ty::Array(ty, _) | ty::Slice(ty)) = cx.typeck_results().expr_ty(expr).kind() else {
+    let Some(ty) = cx.typeck_results().expr_ty(expr).builtin_index() else {
         unreachable!("`expr` must be an array or slice due to `ExprKind::Array`");
     };
 
@@ -85,7 +85,7 @@ fn check_array<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, elements: &
             ExprKind::Path(_) => Some(elements.iter().collect()),
             _ => None,
         })
-        && all_bindings_are_for_conv(cx, &[*ty], expr, elements, &locals, ToType::Array)
+        && all_bindings_are_for_conv(cx, &[ty], expr, elements, &locals, ToType::Array)
         && !is_from_proc_macro(cx, expr)
     {
         span_lint_and_help(

clippy_utils/src/consts.rs

@@ -235,9 +235,7 @@ impl Constant<'_> {
                 _ => None,
             },
             (Self::Vec(l), Self::Vec(r)) => {
-                let (ty::Array(cmp_type, _) | ty::Slice(cmp_type)) = *cmp_type.kind() else {
-                    return None;
-                };
+                let cmp_type = cmp_type.builtin_index()?;
                 iter::zip(l, r)
                     .map(|(li, ri)| Self::partial_cmp(tcx, cmp_type, li, ri))
                     .find(|r| r.is_none_or(|o| o != Ordering::Equal))