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Fix code errors in RFC 2094 #2257

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Dec 23, 2017
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Fix code errors in RFC 2094 #2257

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28 changes: 14 additions & 14 deletions text/2094-nll.md
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Original file line number Diff line number Diff line change
Expand Up @@ -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 => { // |
Expand Down Expand Up @@ -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 => { } // |
Expand All @@ -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
Expand Down Expand Up @@ -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())
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
}
Expand Down