.travis.yml

@@ -10,7 +10,7 @@ before_script:
     set -ex
     rustup --version
     rustc -Vv
-    curl -sSL https://github.com/rust-lang/mdBook/releases/download/v0.3.7/mdbook-v0.3.7-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=$HOME/.cargo/bin
+    curl -sSL https://github.com/rust-lang/mdBook/releases/download/v0.4.5/mdbook-v0.4.5-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=$HOME/.cargo/bin
     mdbook --version
     rustup toolchain update nightly -c rust-docs
 script:

src/flow_control/match/guard.md

@@ -18,6 +18,22 @@ fn main() {
 }
 ```
 
+Note that the compiler does not check arbitrary expressions for whether all
+possible conditions have been checked.  Therefore, you must use the `_` pattern
+at the end.
+
+```rust,editable
+fn main() {
+    let number: u8 = 4;
+
+    match number {
+        i if i == 0 => println!("Zero"),
+        i if i > 0 => println!("Greater than zero"),
+        _ => println!("Fell through"), // This should not be possible to reach
+    }
+}
+```
+
 ### See also:
 
 [Tuples](../../primitives/tuples.md)

src/std_misc/threads/testcase_mapreduce.md

@@ -103,21 +103,13 @@ fn main() {
      * Collect our intermediate results, and combine them into a final result
      ************************************************************************/
 
-    // collect each thread's intermediate results into a new Vec
-    let mut intermediate_sums = vec![];
-    for child in children {
-        // collect each child thread's return-value
-        let intermediate_sum = child.join().unwrap();
-        intermediate_sums.push(intermediate_sum);
-    }
-
-    // combine all intermediate sums into a single final sum.
+    // combine each thread's intermediate results into a single final sum.
     //
     // we use the "turbofish" ::<> to provide sum() with a type hint.
     //
     // TODO: try without the turbofish, by instead explicitly
     // specifying the type of final_result
-    let final_result = intermediate_sums.iter().sum::<u32>();
+    let final_result = children.into_iter().map(|c| c.join().unwrap()).sum::<u32>();
 
     println!("Final sum result: {}", final_result);
 }