From 075a23de6d525373f39b8ef3c7907464620e27bf Mon Sep 17 00:00:00 2001
From: Zachary Dremann <dremann@gmail.com>
Date: Mon, 13 Sep 2021 17:24:52 -0400
Subject: [PATCH] Explicitly implement Borrow for String & Vec for non-nightly

While it isn't as fully featured as the nightly version, this allows
using borrowed keys for `get` for what I believe are the most common
cases: `Borrow<str>` and `Borrow<[T]>`. I believe this is also backward
compatible with eventually enabling `Borrow<D> where K: Borrow<D>`.
---
 src/lib.rs | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 7ea9b85..987fb6d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -26,7 +26,7 @@
 //!
 //! ## Example
 //!
-//! ```rust,no_run
+//! ```rust
 //! extern crate lru;
 //!
 //! use lru::LruCache;
@@ -130,6 +130,20 @@ impl<K> Borrow<K> for KeyRef<K> {
     }
 }
 
+#[cfg(not(feature = "nightly"))]
+impl Borrow<str> for KeyRef<alloc::string::String> {
+    fn borrow(&self) -> &str {
+        unsafe { &*self.k }
+    }
+}
+
+#[cfg(not(feature = "nightly"))]
+impl<T> Borrow<[T]> for KeyRef<alloc::vec::Vec<T>> {
+    fn borrow(&self) -> &[T] {
+        unsafe { &*self.k }
+    }
+}
+
 // Struct used to hold a key value pair. Also contains references to previous and next entries
 // so we can maintain the entries in a linked list ordered by their use.
 struct LruEntry<K, V> {
@@ -1495,7 +1509,6 @@ mod tests {
     }
 
     #[test]
-    #[cfg(feature = "nightly")]
     fn test_get_with_borrow() {
         use alloc::string::String;
 
@@ -1508,7 +1521,6 @@ mod tests {
     }
 
     #[test]
-    #[cfg(feature = "nightly")]
     fn test_get_mut_with_borrow() {
         use alloc::string::String;