Appease new clippy

src/arc_str.rs

@@ -948,22 +948,19 @@ impl From<ArcStr> for alloc::sync::Arc<str> {
 impl From<alloc::rc::Rc<str>> for ArcStr {
     #[inline]
     fn from(s: alloc::rc::Rc<str>) -> Self {
-        let s: &str = &*s;
-        Self::from(s)
+        Self::from(&*s)
     }
 }
 impl From<alloc::sync::Arc<str>> for ArcStr {
     #[inline]
     fn from(s: alloc::sync::Arc<str>) -> Self {
-        let s: &str = &*s;
-        Self::from(s)
+        Self::from(&*s)
     }
 }
 impl<'a> From<Cow<'a, str>> for ArcStr {
     #[inline]
     fn from(s: Cow<'a, str>) -> Self {
-        let s: &str = &*s;
-        Self::from(s)
+        Self::from(&*s)
     }
 }
 impl<'a> From<&'a ArcStr> for Cow<'a, str> {

src/substr.rs

@@ -1,11 +1,12 @@
 #![allow(
-// We follow libstd's lead and prefer to define both.
+    // We follow libstd's lead and prefer to define both.
     clippy::partialeq_ne_impl,
-// This is a really annoying clippy lint, since it's required for so many cases...
+    // This is a really annoying clippy lint, since it's required for so many cases...
     clippy::cast_ptr_alignment,
-// For macros
+    // For macros
     clippy::redundant_slicing,
 )]
+#![cfg_attr(feature = "substr-usize-indices", allow(clippy::unnecessary_cast))]
 use crate::ArcStr;
 use core::ops::{Range, RangeBounds};