Rollup merge of #110394 - scottmcm:less-idx-new, r=WaffleLapkin

Various minor Idx-related tweaks

Nothing particularly exciting here, but a couple of things I noticed as I was looking for more index conversions to simplify.

cc https://github.com/rust-lang/compiler-team/issues/606
r? `@WaffleLapkin`

2 files changed, 4 insertions, 5 deletions

diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs
index c863acde7b0..2b01aca2ee4 100644
--- a/compiler/rustc_abi/src/layout.rs
+++ b/compiler/rustc_abi/src/layout.rs
@@ -461,8 +461,8 @@ pub trait LayoutCalculator {
             let all_indices = variants.indices();
             let needs_disc =
                 |index: VariantIdx| index != largest_variant_index && !absent(&variants[index]);
-            let niche_variants = all_indices.clone().find(|v| needs_disc(*v)).unwrap().index()
-                ..=all_indices.rev().find(|v| needs_disc(*v)).unwrap().index();
+            let niche_variants = all_indices.clone().find(|v| needs_disc(*v)).unwrap()
+                ..=all_indices.rev().find(|v| needs_disc(*v)).unwrap();
 
             let count = niche_variants.size_hint().1.unwrap() as u128;
 
@@ -560,8 +560,7 @@ pub trait LayoutCalculator {
                     tag: niche_scalar,
                     tag_encoding: TagEncoding::Niche {
                         untagged_variant: largest_variant_index,
-                        niche_variants: (VariantIdx::new(*niche_variants.start())
-                            ..=VariantIdx::new(*niche_variants.end())),
+                        niche_variants,
                         niche_start,
                     },
                     tag_field: 0,
diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index 7a3defd2a5d..402ea6ff48f 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -11,7 +11,7 @@ use bitflags::bitflags;
 use rustc_data_structures::intern::Interned;
 #[cfg(feature = "nightly")]
 use rustc_data_structures::stable_hasher::StableOrd;
-use rustc_index::vec::{Idx, IndexSlice, IndexVec};
+use rustc_index::vec::{IndexSlice, IndexVec};
 #[cfg(feature = "nightly")]
 use rustc_macros::HashStable_Generic;
 #[cfg(feature = "nightly")]