Merge pull request #2257 from xfix/patch-2

Fix code errors in RFC 2094

Author: Centril

text/2094-nll.md

@@ -210,9 +210,9 @@ purposes of this section, assume that the `entry` API for maps does
 not exist):
 
 ```rust
-fn get_default<'r,K,V:Default>(map: &'r mut HashMap<K,V>,
-                               key: K)
-                               -> &'r mut V {
+fn get_default<'r,K:Hash+Eq,V:Default>(map: &'r mut HashMap<K,V>,
+                                       key: K)
+                                       -> &'r mut V {
     match map.get_mut(&key) { // -------------+ 'r
         Some(value) => value,              // |
         None => {                          // |
@@ -258,9 +258,9 @@ If we attempt the same workaround for this case that we tried
 in the previous example, we will find that it does not work:
 
 ```rust
-fn get_default1<'r,K,V:Default>(map: &'r mut HashMap<K,V>,
-                                key: K)
-                                -> &'r mut V {
+fn get_default1<'r,K:Hash+Eq,V:Default>(map: &'r mut HashMap<K,V>,
+                                        key: K)
+                                        -> &'r mut V {
     match map.get_mut(&key) { // -------------+ 'r
         Some(value) => return value,       // |
         None => { }                        // |
@@ -281,9 +281,9 @@ the fact that the borrow checker uses the precise control-flow of the
 function to determine which borrows are in scope.
 
 ```rust
-fn get_default2<'r,K,V:Default>(map: &'r mut HashMap<K,V>,
-                                key: K)
-                                -> &'r mut V {
+fn get_default2<'r,K:Hash+Eq,V:Default>(map: &'r mut HashMap<K,V>,
+                                        key: K)
+                                        -> &'r mut V {
     if map.contains(&key) {
     // ^~~~~~~~~~~~~~~~~~ 'n
         return match map.get_mut(&key) { // + 'r
@@ -318,9 +318,9 @@ both nicer to read and more efficient even than the original version,
 since it avoids extra lookups on the "not present" path as well:
 
 ```rust
-fn get_default3<'r,K,V:Default>(map: &'r mut HashMap<K,V>,
-                                key: K)
-                                -> &'r mut V {
+fn get_default3<'r,K:Hash+Eq,V:Default>(map: &'r mut HashMap<K,V>,
+                                        key: K)
+                                        -> &'r mut V {
     map.entry(key)
        .or_insert_with(|| V::default())
 }
@@ -352,7 +352,7 @@ fn to_refs<T>(mut list: &mut List<T>) -> Vec<&mut T> {
     loop {
         result.push(&mut list.value);
         if let Some(n) = list.next.as_mut() {
-            list = &mut n;
+            list = n;
         } else {
             return result;
         }
@@ -400,7 +400,7 @@ fn to_refs<T>(mut list: &mut List<T>) -> Vec<&mut T> {
         let list1 = list;
         result.push(&mut list1.value);
         if let Some(n) = list1.next.as_mut() {
-            list = &mut n;
+            list = n;
         } else {
             return result;
         }