Remove 'std' feature

Cargo.toml

@@ -11,9 +11,5 @@ categories = ["data-structures", "no-std"]
 readme = "README.md"
 include = ["src/**/*", "LICENSE", "README.md"]
 
-[features]
-default = []
-std = []
-
 [dependencies]
 arrayvec = { version = "0.7", default-features = false }

README.md

@@ -7,11 +7,6 @@ Servo's style system.
 insertion, and `O(n)` lookup.  It does not require an allocator and can be
 used in `no_std` crates.  It is implemented in 100% safe Rust.
 
-## Cargo Features
-
-By default, this crate won't need the standard library. However, if the `std` cargo feature is enabled, `insert()` will
-return a replaced value which allows to reuse memory it may have contained.
-
 * [Documentation](https://docs.rs/uluru)
 * [crates.io](https://crates.io/crates/uluru)
 * [Release notes](https://github.com/servo/uluru/releases)

src/lib.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#![cfg_attr(not(feature = "std"), no_std)]
+#![no_std]
 #![deny(unsafe_code)]
 
 //! A simple, fast, least-recently-used (LRU) cache.
@@ -13,7 +13,7 @@
 //! See the [`LRUCache`](LRUCache) docs for details.
 
 use arrayvec::ArrayVec;
-use core::fmt;
+use core::{fmt, mem::replace};
 
 #[cfg(test)]
 mod tests;
@@ -95,8 +95,7 @@ impl<T, const N: usize> LRUCache<T, N> {
     /// Insert a given key in the cache.
     ///
     /// This item becomes the front (most-recently-used) item in the cache.  If the cache is full,
-    /// the back (least-recently-used) item will be removed.
-    #[cfg(feature = "std")]
+    /// the back (least-recently-used) item will be removed and returned.
     pub fn insert(&mut self, val: T) -> Option<T> {
         let entry = Entry {
             val,
@@ -107,7 +106,7 @@ impl<T, const N: usize> LRUCache<T, N> {
         // If the cache is full, replace the oldest entry. Otherwise, add an entry.
         let (new_head, previous_entry) = if self.entries.len() == self.entries.capacity() {
             let i = self.pop_back();
-            let previous_entry = std::mem::replace(&mut self.entries[i as usize], entry);
+            let previous_entry = replace(&mut self.entries[i as usize], entry);
             (i, Some(previous_entry.val))
         } else {
             self.entries.push(entry);
@@ -118,31 +117,6 @@ impl<T, const N: usize> LRUCache<T, N> {
         previous_entry
     }
 
-    /// Insert a given key in the cache.
-    ///
-    /// This item becomes the front (most-recently-used) item in the cache.  If the cache is full,
-    /// the back (least-recently-used) item will be removed.
-    #[cfg(not(feature = "std"))]
-    pub fn insert(&mut self, val: T) {
-        let entry = Entry {
-            val,
-            prev: 0,
-            next: 0,
-        };
-
-        // If the cache is full, replace the oldest entry. Otherwise, add an entry.
-        let new_head = if self.entries.len() == self.entries.capacity() {
-            let i = self.pop_back();
-            self.entries[i as usize] = entry;
-            i
-        } else {
-            self.entries.push(entry);
-            self.entries.len() as u16 - 1
-        };
-
-        self.push_front(new_head);
-    }
-
     /// Returns the first item in the cache that matches the given predicate.
     /// Touches the result (makes it most-recently-used) on a hit.
     pub fn find<F>(&mut self, pred: F) -> Option<&mut T>