4 files changed, 12 insertions, 16 deletions
diff --git a/src/doc/nomicon/src/borrow-splitting.md b/src/doc/nomicon/src/borrow-splitting.md
index 3d13ff954..08b6d0d48 100644
--- a/src/doc/nomicon/src/borrow-splitting.md
+++ b/src/doc/nomicon/src/borrow-splitting.md
@@ -159,7 +159,7 @@ impl<'a, T> Iterator for IterMut<'a, T> {
     type Item = &'a mut T;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let slice = mem::replace(&mut self.0, &mut []);
+        let slice = mem::take(&mut self.0);
         if slice.is_empty() { return None; }
 
         let (l, r) = slice.split_at_mut(1);
@@ -170,7 +170,7 @@ impl<'a, T> Iterator for IterMut<'a, T> {
 
 impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
     fn next_back(&mut self) -> Option<Self::Item> {
-        let slice = mem::replace(&mut self.0, &mut []);
+        let slice = mem::take(&mut self.0);
         if slice.is_empty() { return None; }
 
         let new_len = slice.len() - 1;
diff --git a/src/doc/nomicon/src/ffi.md b/src/doc/nomicon/src/ffi.md
index 9b0ff98e6..8d1a882b3 100644
--- a/src/doc/nomicon/src/ffi.md
+++ b/src/doc/nomicon/src/ffi.md
@@ -659,7 +659,8 @@ Certain Rust types are defined to never be `null`. This includes references (`&T
 `&mut T`), boxes (`Box<T>`), and function pointers (`extern "abi" fn()`). When
 interfacing with C, pointers that might be `null` are often used, which would seem to
 require some messy `transmute`s and/or unsafe code to handle conversions to/from Rust types.
-However, the language provides a workaround.
+However, trying to construct/work with these invalid values **is undefined behavior**,
+so you should use the following workaround instead.
 
 As a special case, an `enum` is eligible for the "nullable pointer optimization" if it contains
 exactly two variants, one of which contains no data and the other contains a field of one of the
diff --git a/src/doc/nomicon/src/lifetime-mismatch.md b/src/doc/nomicon/src/lifetime-mismatch.md
index bc53f06f8..ecb6cf205 100644
--- a/src/doc/nomicon/src/lifetime-mismatch.md
+++ b/src/doc/nomicon/src/lifetime-mismatch.md
@@ -65,7 +65,7 @@ fn main() {
 
 The lifetime system is forced to extend the `&mut foo` to have lifetime `'c`,
 due to the lifetime of `loan` and `mutate_and_share`'s signature. Then when we
-try to call `share`, and it sees we're trying to alias that `&'c mut foo` and
+try to call `share`, it sees we're trying to alias that `&'c mut foo` and
 blows up in our face!
 
 This program is clearly correct according to the reference semantics we actually
diff --git a/src/doc/nomicon/src/vec/vec-raw.md b/src/doc/nomicon/src/vec/vec-raw.md
index 728feaa58..0bca2daf8 100644
--- a/src/doc/nomicon/src/vec/vec-raw.md
+++ b/src/doc/nomicon/src/vec/vec-raw.md
@@ -28,18 +28,13 @@ impl<T> RawVec<T> {
     }
 
     fn grow(&mut self) {
-        let (new_cap, new_layout) = if self.cap == 0 {
-            (1, Layout::array::<T>(1).unwrap())
-        } else {
-            // This can't overflow because we ensure self.cap <= isize::MAX.
-            let new_cap = 2 * self.cap;
-
-            // Layout::array checks that the number of bytes is <= usize::MAX,
-            // but this is redundant since old_layout.size() <= isize::MAX,
-            // so the `unwrap` should never fail.
-            let new_layout = Layout::array::<T>(new_cap).unwrap();
-            (new_cap, new_layout)
-        };
+        // This can't overflow because we ensure self.cap <= isize::MAX.
+        let new_cap = if self.cap == 0 { 1 } else { 2 * self.cap };
+
+        // Layout::array checks that the number of bytes is <= usize::MAX,
+        // but this is redundant since old_layout.size() <= isize::MAX,
+        // so the `unwrap` should never fail.
+        let new_layout = Layout::array::<T>(new_cap).unwrap();
 
         // Ensure that the new allocation doesn't exceed `isize::MAX` bytes.
         assert!(new_layout.size() <= isize::MAX as usize, "Allocation too large");