libs: doc comments

37 files changed, 142 insertions, 138 deletions

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index fb8d7e5d088..8383d305518 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -130,7 +130,7 @@
 //!
 //! This is simply a special - but common - case of the previous: hiding mutability for operations
 //! that appear to be immutable. The `clone` method is expected to not change the source value, and
-//! is declared to take `&self`, not `&mut self`. Therefore any mutation that happens in the
+//! is declared to take `&self`, not `&mut self`. Therefore, any mutation that happens in the
 //! `clone` method must use cell types. For example, `Rc<T>` maintains its reference counts within a
 //! `Cell<T>`.
 //!
@@ -1145,7 +1145,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
         }
     }
 
-    /// Make a new `Ref` for a component of the borrowed data.
+    /// Makes a new `Ref` for a component of the borrowed data.
     ///
     /// The `RefCell` is already immutably borrowed, so this cannot fail.
     ///
@@ -1217,7 +1217,7 @@ impl<T: ?Sized + fmt::Display> fmt::Display for Ref<'_, T> {
 }
 
 impl<'b, T: ?Sized> RefMut<'b, T> {
-    /// Make a new `RefMut` for a component of the borrowed data, e.g., an enum
+    /// Makes a new `RefMut` for a component of the borrowed data, e.g., an enum
     /// variant.
     ///
     /// The `RefCell` is already mutably borrowed, so this cannot fail.
@@ -1416,7 +1416,7 @@ impl<T: ?Sized + fmt::Display> fmt::Display for RefMut<'_, T> {
 /// co-exist with it. A `&mut T` must always be unique.
 ///
 /// Note that while mutating or mutably aliasing the contents of an `&UnsafeCell<T>` is
-/// okay (provided you enforce the invariants some other way), it is still undefined behavior
+/// ok (provided you enforce the invariants some other way), it is still undefined behavior
 /// to have multiple `&mut UnsafeCell<T>` aliases.
 ///
 /// # Examples
diff --git a/src/libcore/char/decode.rs b/src/libcore/char/decode.rs
index 510c46cdca0..133c9169df8 100644
--- a/src/libcore/char/decode.rs
+++ b/src/libcore/char/decode.rs
@@ -20,7 +20,7 @@ pub struct DecodeUtf16Error {
     code: u16,
 }
 
-/// Create an iterator over the UTF-16 encoded code points in `iter`,
+/// Creates an iterator over the UTF-16 encoded code points in `iter`,
 /// returning unpaired surrogates as `Err`s.
 ///
 /// # Examples
diff --git a/src/libcore/char/methods.rs b/src/libcore/char/methods.rs
index fbc9a4a6b8e..72967b9adf7 100644
--- a/src/libcore/char/methods.rs
+++ b/src/libcore/char/methods.rs
@@ -524,7 +524,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is an alphabetic code point, and false if not.
+    /// Returns `true` if this `char` is an alphabetic code point, and false if not.
     ///
     /// # Examples
     ///
@@ -548,7 +548,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` satisfies the 'XID_Start' Unicode property, and false
+    /// Returns `true` if this `char` satisfies the 'XID_Start' Unicode property, and false
     /// otherwise.
     ///
     /// 'XID_Start' is a Unicode Derived Property specified in
@@ -562,7 +562,7 @@ impl char {
         derived_property::XID_Start(self)
     }
 
-    /// Returns true if this `char` satisfies the 'XID_Continue' Unicode property, and false
+    /// Returns `true` if this `char` satisfies the 'XID_Continue' Unicode property, and false
     /// otherwise.
     ///
     /// 'XID_Continue' is a Unicode Derived Property specified in
@@ -576,7 +576,7 @@ impl char {
         derived_property::XID_Continue(self)
     }
 
-    /// Returns true if this `char` is lowercase, and false otherwise.
+    /// Returns `true` if this `char` is lowercase.
     ///
     /// 'Lowercase' is defined according to the terms of the Unicode Derived Core
     /// Property `Lowercase`.
@@ -604,7 +604,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is uppercase, and false otherwise.
+    /// Returns `true` if this `char` is uppercase.
     ///
     /// 'Uppercase' is defined according to the terms of the Unicode Derived Core
     /// Property `Uppercase`.
@@ -632,7 +632,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is whitespace, and false otherwise.
+    /// Returns `true` if this `char` is whitespace.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived Core
     /// Property `White_Space`.
@@ -659,7 +659,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is alphanumeric, and false otherwise.
+    /// Returns `true` if this `char` is alphanumeric.
     ///
     /// 'Alphanumeric'-ness is defined in terms of the Unicode General Categories
     /// 'Nd', 'Nl', 'No' and the Derived Core Property 'Alphabetic'.
@@ -684,7 +684,7 @@ impl char {
         self.is_alphabetic() || self.is_numeric()
     }
 
-    /// Returns true if this `char` is a control code point, and false otherwise.
+    /// Returns `true` if this `char` is a control code point.
     ///
     /// 'Control code point' is defined in terms of the Unicode General
     /// Category `Cc`.
@@ -704,7 +704,7 @@ impl char {
         general_category::Cc(self)
     }
 
-    /// Returns true if this `char` is an extended grapheme character, and false otherwise.
+    /// Returns `true` if this `char` is an extended grapheme character.
     ///
     /// 'Extended grapheme character' is defined in terms of the Unicode Shaping and Rendering
     /// Category `Grapheme_Extend`.
@@ -713,7 +713,7 @@ impl char {
         derived_property::Grapheme_Extend(self)
     }
 
-    /// Returns true if this `char` is numeric, and false otherwise.
+    /// Returns `true` if this `char` is numeric.
     ///
     /// 'Numeric'-ness is defined in terms of the Unicode General Categories
     /// 'Nd', 'Nl', 'No'.
diff --git a/src/libcore/default.rs b/src/libcore/default.rs
index 0e47c2fd0b5..5ad05b38247 100644
--- a/src/libcore/default.rs
+++ b/src/libcore/default.rs
@@ -54,7 +54,7 @@
 ///
 /// ## How can I implement `Default`?
 ///
-/// Provide an implementation for the `default()` method that returns the value of
+/// Provides an implementation for the `default()` method that returns the value of
 /// your type that should be the default:
 ///
 /// ```
diff --git a/src/libcore/ffi.rs b/src/libcore/ffi.rs
index 644380c69f2..d88793f2801 100644
--- a/src/libcore/ffi.rs
+++ b/src/libcore/ffi.rs
@@ -184,7 +184,7 @@ impl<'a> VaList<'a> {
         va_arg(self)
     }
 
-    /// Copy the `va_list` at the current location.
+    /// Copies the `va_list` at the current location.
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
@@ -213,7 +213,7 @@ extern "rust-intrinsic" {
     /// `va_copy`.
     fn va_end(ap: &mut VaList);
 
-    /// Copy the current location of arglist `src` to the arglist `dst`.
+    /// Copies the current location of arglist `src` to the arglist `dst`.
     #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
                   not(target_arch = "x86_64")),
               windows))]
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 530b2f52c0d..2ce58c803b8 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -483,12 +483,12 @@ impl Display for Arguments<'_> {
 /// implementations, such as [`debug_struct`][debug_struct].
 ///
 /// `Debug` implementations using either `derive` or the debug builder API
-/// on [`Formatter`] support pretty printing using the alternate flag: `{:#?}`.
+/// on [`Formatter`] support pretty-printing using the alternate flag: `{:#?}`.
 ///
 /// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct
 /// [`Formatter`]: ../../std/fmt/struct.Formatter.html
 ///
-/// Pretty printing with `#?`:
+/// Pretty-printing with `#?`:
 ///
 /// ```
 /// #[derive(Debug)]
diff --git a/src/libcore/future/future.rs b/src/libcore/future/future.rs
index 539b07fc21e..0f142347a95 100644
--- a/src/libcore/future/future.rs
+++ b/src/libcore/future/future.rs
@@ -60,7 +60,7 @@ pub trait Future {
     /// progress, meaning that each time the current task is woken up, it should
     /// actively re-`poll` pending futures that it still has an interest in.
     ///
-    /// The `poll` function is not called repeatedly in a tight loop-- instead,
+    /// The `poll` function is not called repeatedly in a tight loop -- instead,
     /// it should only be called when the future indicates that it is ready to
     /// make progress (by calling `wake()`). If you're familiar with the
     /// `poll(2)` or `select(2)` syscalls on Unix it's worth noting that futures
diff --git a/src/libcore/hash/sip.rs b/src/libcore/hash/sip.rs
index 18f09f4c5dd..235c79307ab 100644
--- a/src/libcore/hash/sip.rs
+++ b/src/libcore/hash/sip.rs
@@ -10,7 +10,7 @@ use mem;
 /// An implementation of SipHash 1-3.
 ///
 /// This is currently the default hashing function used by standard library
-/// (eg. `collections::HashMap` uses it by default).
+/// (e.g., `collections::HashMap` uses it by default).
 ///
 /// See: <https://131002.net/siphash>
 #[unstable(feature = "hashmap_internals", issue = "0")]
@@ -90,7 +90,7 @@ macro_rules! compress {
     });
 }
 
-/// Load an integer of the desired type from a byte stream, in LE order. Uses
+/// Loads an integer of the desired type from a byte stream, in LE order. Uses
 /// `copy_nonoverlapping` to let the compiler generate the most efficient way
 /// to load it from a possibly unaligned address.
 ///
@@ -107,7 +107,7 @@ macro_rules! load_int_le {
     });
 }
 
-/// Load an u64 using up to 7 bytes of a byte slice.
+/// Loads an u64 using up to 7 bytes of a byte slice.
 ///
 /// Unsafe because: unchecked indexing at start..start+len
 #[inline]
diff --git a/src/libcore/hint.rs b/src/libcore/hint.rs
index ad5a2071a73..89de5c1bc8a 100644
--- a/src/libcore/hint.rs
+++ b/src/libcore/hint.rs
@@ -34,7 +34,7 @@ use intrinsics;
 ///     use std::hint::unreachable_unchecked;
 ///
 ///     // `b.saturating_add(1)` is always positive (not zero),
-///     // hence `checked_div` will never return None.
+///     // hence `checked_div` will never return `None`.
 ///     // Therefore, the else branch is unreachable.
 ///     a.checked_div(b.saturating_add(1))
 ///         .unwrap_or_else(|| unsafe { unreachable_unchecked() })
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index c29358c4c4a..f6de7566be9 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -315,35 +315,35 @@ extern "rust-intrinsic" {
     /// [`AtomicBool::swap`](../../std/sync/atomic/struct.AtomicBool.html#method.swap).
     pub fn atomic_xchg_relaxed<T>(dst: *mut T, src: T) -> T;
 
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::SeqCst`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Acquire`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_acq<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Release`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_rel<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::AcqRel`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_acqrel<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Relaxed`](../../std/sync/atomic/enum.Ordering.html)
@@ -556,7 +556,7 @@ extern "rust-intrinsic" {
     pub fn atomic_umax_relaxed<T>(dst: *mut T, src: T) -> T;
 
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -564,7 +564,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_read_data<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -572,7 +572,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_write_data<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -580,7 +580,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_read_instruction<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -857,7 +857,7 @@ extern "rust-intrinsic" {
     ///
     /// // The no-copy, unsafe way, still using transmute, but not UB.
     /// // This is equivalent to the original, but safer, and reuses the
-    /// // same Vec internals. Therefore the new inner type must have the
+    /// // same `Vec` internals. Therefore, the new inner type must have the
     /// // exact same size, and the same alignment, as the old type.
     /// // The same caveats exist for this method as transmute, for
     /// // the original inner type (`&i32`) to the converted inner type
@@ -875,8 +875,8 @@ extern "rust-intrinsic" {
     /// ```
     /// use std::{slice, mem};
     ///
-    /// // There are multiple ways to do this; and there are multiple problems
-    /// // with the following, transmute, way.
+    /// // There are multiple ways to do this, and there are multiple problems
+    /// // with the following (transmute) way.
     /// fn split_at_mut_transmute<T>(slice: &mut [T], mid: usize)
     ///                              -> (&mut [T], &mut [T]) {
     ///     let len = slice.len();
@@ -1200,19 +1200,19 @@ extern "rust-intrinsic" {
     /// unless size is equal to zero.
     pub fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize);
 
-    /// Perform a volatile load from the `src` pointer.
+    /// Performs a volatile load from the `src` pointer.
     /// The stabilized version of this intrinsic is
     /// [`std::ptr::read_volatile`](../../std/ptr/fn.read_volatile.html).
     pub fn volatile_load<T>(src: *const T) -> T;
-    /// Perform a volatile store to the `dst` pointer.
+    /// Performs a volatile store to the `dst` pointer.
     /// The stabilized version of this intrinsic is
     /// [`std::ptr::write_volatile`](../../std/ptr/fn.write_volatile.html).
     pub fn volatile_store<T>(dst: *mut T, val: T);
 
-    /// Perform a volatile load from the `src` pointer
+    /// Performs a volatile load from the `src` pointer
     /// The pointer is not required to be aligned.
     pub fn unaligned_volatile_load<T>(src: *const T) -> T;
-    /// Perform a volatile store to the `dst` pointer.
+    /// Performs a volatile store to the `dst` pointer.
     /// The pointer is not required to be aligned.
     pub fn unaligned_volatile_store<T>(dst: *mut T, val: T);
 
diff --git a/src/libcore/iter/range.rs b/src/libcore/iter/range.rs
index 66c09a0ddd0..a3e9cfa9493 100644
--- a/src/libcore/iter/range.rs
+++ b/src/libcore/iter/range.rs
@@ -20,19 +20,19 @@ pub trait Step: Clone + PartialOrd + Sized {
     /// without overflow.
     fn steps_between(start: &Self, end: &Self) -> Option<usize>;
 
-    /// Replaces this step with `1`, returning itself
+    /// Replaces this step with `1`, returning itself.
     fn replace_one(&mut self) -> Self;
 
-    /// Replaces this step with `0`, returning itself
+    /// Replaces this step with `0`, returning itself.
     fn replace_zero(&mut self) -> Self;
 
-    /// Adds one to this step, returning the result
+    /// Adds one to this step, returning the result.
     fn add_one(&self) -> Self;
 
-    /// Subtracts one to this step, returning the result
+    /// Subtracts one to this step, returning the result.
     fn sub_one(&self) -> Self;
 
-    /// Add an usize, returning None on overflow
+    /// Adds a `usize`, returning `None` on overflow.
     fn add_usize(&self, n: usize) -> Option<Self>;
 }
 
diff --git a/src/libcore/iter/traits/exact_size.rs b/src/libcore/iter/traits/exact_size.rs
index 3bfba29e219..d6eab40213e 100644
--- a/src/libcore/iter/traits/exact_size.rs
+++ b/src/libcore/iter/traits/exact_size.rs
@@ -104,7 +104,7 @@ pub trait ExactSizeIterator: Iterator {
         lower
     }
 
-    /// Returns whether the iterator is empty.
+    /// Returns `true` if the iterator is empty.
     ///
     /// This method has a default implementation using `self.len()`, so you
     /// don't need to implement it yourself.
diff --git a/src/libcore/iter/traits/iterator.rs b/src/libcore/iter/traits/iterator.rs
index 1c86745d9ba..861e9c3157a 100644
--- a/src/libcore/iter/traits/iterator.rs
+++ b/src/libcore/iter/traits/iterator.rs
@@ -120,7 +120,7 @@ pub trait Iterator {
     /// // ... and then None once it's over.
     /// assert_eq!(None, iter.next());
     ///
-    /// // More calls may or may not return None. Here, they always will.
+    /// // More calls may or may not return `None`. Here, they always will.
     /// assert_eq!(None, iter.next());
     /// assert_eq!(None, iter.next());
     /// ```
@@ -1215,7 +1215,7 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(4));
     /// assert_eq!(iter.next(), None);
     ///
-    /// // it will always return None after the first time.
+    /// // it will always return `None` after the first time.
     /// assert_eq!(iter.next(), None);
     /// assert_eq!(iter.next(), None);
     /// assert_eq!(iter.next(), None);
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index d81d309a81a..2a9cb75df2c 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -1,4 +1,4 @@
-/// Entry point of thread panic, for details, see std::macros
+/// Entry point of thread panic. For details, see `std::macros`.
 #[macro_export]
 #[allow_internal_unstable]
 #[stable(feature = "core", since = "1.6.0")]
@@ -493,7 +493,7 @@ macro_rules! unreachable {
 /// A standardized placeholder for marking unfinished code.
 ///
 /// This can be useful if you are prototyping and are just looking to have your
-/// code typecheck, or if you're implementing a trait that requires multiple
+/// code type-check, or if you're implementing a trait that requires multiple
 /// methods, and you're only planning on using one of them.
 ///
 /// # Panics
diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index 855b8ba7f96..2a493e88fe8 100644
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -295,7 +295,7 @@ pub const fn size_of<T>() -> usize {
 /// Returns the size of the pointed-to value in bytes.
 ///
 /// This is usually the same as `size_of::<T>()`. However, when `T` *has* no
-/// statically known size, e.g., a slice [`[T]`][slice] or a [trait object],
+/// statically-known size, e.g., a slice [`[T]`][slice] or a [trait object],
 /// then `size_of_val` can be used to get the dynamically-known size.
 ///
 /// [slice]: ../../std/primitive.slice.html
@@ -403,7 +403,7 @@ pub fn align_of_val<T: ?Sized>(val: &T) -> usize {
     unsafe { intrinsics::min_align_of_val(val) }
 }
 
-/// Returns whether dropping values of type `T` matters.
+/// Returns `true` if dropping values of type `T` matters.
 ///
 /// This is purely an optimization hint, and may be implemented conservatively:
 /// it may return `true` for types that don't actually need to be dropped.
@@ -958,7 +958,7 @@ impl<T> ManuallyDrop<T> {
         ManuallyDrop { value }
     }
 
-    /// Extract the value from the `ManuallyDrop` container.
+    /// Extracts the value from the `ManuallyDrop` container.
     ///
     /// This allows the value to be dropped again.
     ///
@@ -1038,26 +1038,29 @@ impl<T: ?Sized> DerefMut for ManuallyDrop<T> {
 /// A newtype to construct uninitialized instances of `T`.
 ///
 /// The compiler, in general, assumes that variables are properly initialized
-/// at their respective type.  For example, a variable of reference type must
-/// be aligned and non-NULL.  This is an invariant that must *always* be upheld,
-/// even in unsafe code.  As a consequence, 0-initializing a variable of reference
+/// at their respective type. For example, a variable of reference type must
+/// be aligned and non-NULL. This is an invariant that must *always* be upheld,
+/// even in unsafe code. As a consequence, zero-initializing a variable of reference
 /// type causes instantaneous undefined behavior, no matter whether that reference
 /// ever gets used to access memory:
+///
 /// ```rust,no_run
 /// use std::mem;
 ///
 /// let x: &i32 = unsafe { mem::zeroed() }; // undefined behavior!
 /// ```
+///
 /// This is exploited by the compiler for various optimizations, such as eliding
 /// run-time checks and optimizing `enum` layout.
 ///
-/// Not initializing memory at all (instead of 0-initializing it) causes the same
+/// Not initializing memory at all (instead of zero--initializing it) causes the same
 /// issue: after all, the initial value of the variable might just happen to be
 /// one that violates the invariant.
 ///
 /// `MaybeUninit` serves to enable unsafe code to deal with uninitialized data:
 /// it is a signal to the compiler indicating that the data here might *not*
 /// be initialized:
+///
 /// ```rust
 /// #![feature(maybe_uninit)]
 /// use std::mem::MaybeUninit;
@@ -1070,6 +1073,7 @@ impl<T: ?Sized> DerefMut for ManuallyDrop<T> {
 /// // initializing `x`!
 /// let x = unsafe { x.into_initialized() };
 /// ```
+///
 /// The compiler then knows to not optimize this code.
 #[allow(missing_debug_implementations)]
 #[unstable(feature = "maybe_uninit", issue = "53491")]
@@ -1090,7 +1094,7 @@ impl<T> MaybeUninit<T> {
         MaybeUninit { value: ManuallyDrop::new(val) }
     }
 
-    /// Create a new `MaybeUninit` in an uninitialized state.
+    /// Creates a new `MaybeUninit` in an uninitialized state.
     ///
     /// Note that dropping a `MaybeUninit` will never call `T`'s drop code.
     /// It is your responsibility to make sure `T` gets dropped if it got initialized.
@@ -1100,7 +1104,7 @@ impl<T> MaybeUninit<T> {
         MaybeUninit { uninit: () }
     }
 
-    /// Create a new `MaybeUninit` in an uninitialized state, with the memory being
+    /// Creates a new `MaybeUninit` in an uninitialized state, with the memory being
     /// filled with `0` bytes. It depends on `T` whether that already makes for
     /// proper initialization. For example, `MaybeUninit<usize>::zeroed()` is initialized,
     /// but `MaybeUninit<&'static i32>::zeroed()` is not because references must not
@@ -1118,9 +1122,9 @@ impl<T> MaybeUninit<T> {
         u
     }
 
-    /// Set the value of the `MaybeUninit`. This overwrites any previous value without dropping it.
-    /// For your convenience, this also returns a mutable reference to the (now
-    /// safely initialized) content of `self`.
+    /// Sets the value of the `MaybeUninit`. This overwrites any previous value without dropping it.
+    /// For your convenience, this also returns a mutable reference to the (now safely initialized)
+    /// contents of `self`.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
     pub fn set(&mut self, val: T) -> &mut T {
@@ -1130,7 +1134,7 @@ impl<T> MaybeUninit<T> {
         }
     }
 
-    /// Extract the value from the `MaybeUninit` container. This is a great way
+    /// Extracts the value from the `MaybeUninit` container. This is a great way
     /// to ensure that the data will get dropped, because the resulting `T` is
     /// subject to the usual drop handling.
     ///
@@ -1145,7 +1149,7 @@ impl<T> MaybeUninit<T> {
         ManuallyDrop::into_inner(self.value)
     }
 
-    /// Deprecated alternative to `into_initialized`.  Will never get stabilized.
+    /// Deprecated alternative to `into_initialized`. Will never get stabilized.
     /// Exists only to transition stdsimd to `into_initialized`.
     #[inline(always)]
     #[allow(unused)]
@@ -1153,7 +1157,7 @@ impl<T> MaybeUninit<T> {
         self.into_initialized()
     }
 
-    /// Get a reference to the contained value.
+    /// Gets a reference to the contained value.
     ///
     /// # Unsafety
     ///
@@ -1165,7 +1169,7 @@ impl<T> MaybeUninit<T> {
         &*self.value
     }
 
-    /// Get a mutable reference to the contained value.
+    /// Gets a mutable reference to the contained value.
     ///
     /// # Unsafety
     ///
@@ -1180,7 +1184,7 @@ impl<T> MaybeUninit<T> {
         &mut *self.value
     }
 
-    /// Get a pointer to the contained value. Reading from this pointer or turning it
+    /// Gets a pointer to the contained value. Reading from this pointer or turning it
     /// into a reference will be undefined behavior unless the `MaybeUninit` is initialized.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
@@ -1188,7 +1192,7 @@ impl<T> MaybeUninit<T> {
         unsafe { &*self.value as *const T }
     }
 
-    /// Get a mutable pointer to the contained value. Reading from this pointer or turning it
+    /// Get sa mutable pointer to the contained value. Reading from this pointer or turning it
     /// into a reference will be undefined behavior unless the `MaybeUninit` is initialized.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
@@ -1196,14 +1200,14 @@ impl<T> MaybeUninit<T> {
         unsafe { &mut *self.value as *mut T }
     }
 
-    /// Get a pointer to the first element of the array.
+    /// Gets a pointer to the first element of the array.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
     pub fn first_ptr(this: &[MaybeUninit<T>]) -> *const T {
         this as *const [MaybeUninit<T>] as *const T
     }
 
-    /// Get a mutable pointer to the first element of the array.
+    /// Gets a mutable pointer to the first element of the array.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
     pub fn first_ptr_mut(this: &mut [MaybeUninit<T>]) -> *mut T {
diff --git a/src/libcore/num/dec2flt/algorithm.rs b/src/libcore/num/dec2flt/algorithm.rs
index d56fa9662a9..3b57bb7544b 100644
--- a/src/libcore/num/dec2flt/algorithm.rs
+++ b/src/libcore/num/dec2flt/algorithm.rs
@@ -61,7 +61,7 @@ mod fpu_precision {
         unsafe { asm!("fldcw $0" :: "m" (cw) :: "volatile") }
     }
 
-    /// Set the precision field of the FPU to `T` and return a `FPUControlWord`
+    /// Sets the precision field of the FPU to `T` and returns a `FPUControlWord`.
     pub fn set_precision<T>() -> FPUControlWord {
         let cw = 0u16;
 
diff --git a/src/libcore/num/dec2flt/mod.rs b/src/libcore/num/dec2flt/mod.rs
index a1bf6f824f6..47ea5aa5ff0 100644
--- a/src/libcore/num/dec2flt/mod.rs
+++ b/src/libcore/num/dec2flt/mod.rs
@@ -54,7 +54,7 @@
 //! operations as well, if you want 0.5 ULP accuracy you need to do *everything* in full precision
 //! and round *exactly once, at the end*, by considering all truncated bits at once.
 //!
-//! FIXME Although some code duplication is necessary, perhaps parts of the code could be shuffled
+//! FIXME: Although some code duplication is necessary, perhaps parts of the code could be shuffled
 //! around such that less code is duplicated. Large parts of the algorithms are independent of the
 //! float type to output, or only needs access to a few constants, which could be passed in as
 //! parameters.
@@ -219,7 +219,7 @@ fn extract_sign(s: &str) -> (Sign, &str) {
     }
 }
 
-/// Convert a decimal string into a floating point number.
+/// Converts a decimal string into a floating point number.
 fn dec2flt<T: RawFloat>(s: &str) -> Result<T, ParseFloatError> {
     if s.is_empty() {
         return Err(pfe_empty())
diff --git a/src/libcore/num/dec2flt/num.rs b/src/libcore/num/dec2flt/num.rs
index b76c58cc66e..12671318571 100644
--- a/src/libcore/num/dec2flt/num.rs
+++ b/src/libcore/num/dec2flt/num.rs
@@ -27,7 +27,7 @@ pub fn compare_with_half_ulp(f: &Big, ones_place: usize) -> Ordering {
     Equal
 }
 
-/// Convert an ASCII string containing only decimal digits to a `u64`.
+/// Converts an ASCII string containing only decimal digits to a `u64`.
 ///
 /// Does not perform checks for overflow or invalid characters, so if the caller is not careful,
 /// the result is bogus and can panic (though it won't be `unsafe`). Additionally, empty strings
@@ -44,7 +44,7 @@ pub fn from_str_unchecked<'a, T>(bytes: T) -> u64 where T : IntoIterator<Item=&'
     result
 }
 
-/// Convert a string of ASCII digits into a bignum.
+/// Converts a string of ASCII digits into a bignum.
 ///
 /// Like `from_str_unchecked`, this function relies on the parser to weed out non-digits.
 pub fn digits_to_big(integral: &[u8], fractional: &[u8]) -> Big {
@@ -69,7 +69,7 @@ pub fn to_u64(x: &Big) -> u64 {
 }
 
 
-/// Extract a range of bits.
+/// Extracts a range of bits.
 
 /// Index 0 is the least significant bit and the range is half-open as usual.
 /// Panics if asked to extract more bits than fit into the return type.
diff --git a/src/libcore/num/dec2flt/parse.rs b/src/libcore/num/dec2flt/parse.rs
index 9e075e43303..933f8c1d3f7 100644
--- a/src/libcore/num/dec2flt/parse.rs
+++ b/src/libcore/num/dec2flt/parse.rs
@@ -42,7 +42,7 @@ pub enum ParseResult<'a> {
     Invalid,
 }
 
-/// Check if the input string is a valid floating point number and if so, locate the integral
+/// Checks if the input string is a valid floating point number and if so, locate the integral
 /// part, the fractional part, and the exponent in it. Does not handle signs.
 pub fn parse_decimal(s: &str) -> ParseResult {
     if s.is_empty() {
diff --git a/src/libcore/num/dec2flt/rawfp.rs b/src/libcore/num/dec2flt/rawfp.rs
index 06d7fb8d103..b65f539b29c 100644
--- a/src/libcore/num/dec2flt/rawfp.rs
+++ b/src/libcore/num/dec2flt/rawfp.rs
@@ -240,7 +240,7 @@ impl RawFloat for f64 {
     fn from_bits(v: Self::Bits) -> Self { Self::from_bits(v) }
 }
 
-/// Convert an Fp to the closest machine float type.
+/// Converts an `Fp` to the closest machine float type.
 /// Does not handle subnormal results.
 pub fn fp_to_float<T: RawFloat>(x: Fp) -> T {
     let x = x.normalize();
@@ -319,7 +319,7 @@ pub fn big_to_fp(f: &Big) -> Fp {
     }
 }
 
-/// Find the largest floating point number strictly smaller than the argument.
+/// Finds the largest floating point number strictly smaller than the argument.
 /// Does not handle subnormals, zero, or exponent underflow.
 pub fn prev_float<T: RawFloat>(x: T) -> T {
     match x.classify() {
diff --git a/src/libcore/num/f32.rs b/src/libcore/num/f32.rs
index 68da79135d3..dc0580764ac 100644
--- a/src/libcore/num/f32.rs
+++ b/src/libcore/num/f32.rs
@@ -144,7 +144,7 @@ pub mod consts {
 #[lang = "f32"]
 #[cfg(not(test))]
 impl f32 {
-    /// Returns `true` if this value is `NaN` and false otherwise.
+    /// Returns `true` if this value is `NaN`.
     ///
     /// ```
     /// use std::f32;
@@ -169,8 +169,8 @@ impl f32 {
         f32::from_bits(self.to_bits() & 0x7fff_ffff)
     }
 
-    /// Returns `true` if this value is positive infinity or negative infinity and
-    /// false otherwise.
+    /// Returns `true` if this value is positive infinity or negative infinity, and
+    /// `false` otherwise.
     ///
     /// ```
     /// use std::f32;
@@ -272,7 +272,7 @@ impl f32 {
         }
     }
 
-    /// Returns `true` if and only if `self` has a positive sign, including `+0.0`, `NaN`s with
+    /// Returns `true` if `self` has a positive sign, including `+0.0`, `NaN`s with
     /// positive sign bit and positive infinity.
     ///
     /// ```
@@ -288,7 +288,7 @@ impl f32 {
         !self.is_sign_negative()
     }
 
-    /// Returns `true` if and only if `self` has a negative sign, including `-0.0`, `NaN`s with
+    /// Returns `true` if `self` has a negative sign, including `-0.0`, `NaN`s with
     /// negative sign bit and negative infinity.
     ///
     /// ```
diff --git a/src/libcore/num/f64.rs b/src/libcore/num/f64.rs
index b6773915481..c3677f8c8fa 100644
--- a/src/libcore/num/f64.rs
+++ b/src/libcore/num/f64.rs
@@ -144,7 +144,7 @@ pub mod consts {
 #[lang = "f64"]
 #[cfg(not(test))]
 impl f64 {
-    /// Returns `true` if this value is `NaN` and false otherwise.
+    /// Returns `true` if this value is `NaN`.
     ///
     /// ```
     /// use std::f64;
@@ -169,8 +169,8 @@ impl f64 {
         f64::from_bits(self.to_bits() & 0x7fff_ffff_ffff_ffff)
     }
 
-    /// Returns `true` if this value is positive infinity or negative infinity and
-    /// false otherwise.
+    /// Returns `true` if this value is positive infinity or negative infinity, and
+    /// `false` otherwise.
     ///
     /// ```
     /// use std::f64;
@@ -272,7 +272,7 @@ impl f64 {
         }
     }
 
-    /// Returns `true` if and only if `self` has a positive sign, including `+0.0`, `NaN`s with
+    /// Returns `true` if `self` has a positive sign, including `+0.0`, `NaN`s with
     /// positive sign bit and positive infinity.
     ///
     /// ```
@@ -296,7 +296,7 @@ impl f64 {
         self.is_sign_positive()
     }
 
-    /// Returns `true` if and only if `self` has a negative sign, including `-0.0`, `NaN`s with
+    /// Returns `true` if `self` has a negative sign, including `-0.0`, `NaN`s with
     /// negative sign bit and negative infinity.
     ///
     /// ```
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index f80f8392827..6b3ec2c21be 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -52,7 +52,7 @@ assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", s
             }
 
             impl $Ty {
-                /// Create a non-zero without checking the value.
+                /// Creates a non-zero without checking the value.
                 ///
                 /// # Safety
                 ///
@@ -63,7 +63,7 @@ assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", s
                     $Ty(n)
                 }
 
-                /// Create a non-zero if the given value is not zero.
+                /// Creates a non-zero if the given value is not zero.
                 #[$stability]
                 #[inline]
                 pub fn new(n: $Int) -> Option<Self> {
diff --git a/src/libcore/ops/arith.rs b/src/libcore/ops/arith.rs
index 202beddfcb0..0252edee231 100644
--- a/src/libcore/ops/arith.rs
+++ b/src/libcore/ops/arith.rs
@@ -49,7 +49,7 @@
 /// }
 ///
 /// // Notice that the implementation uses the associated type `Output`.
-/// impl<T: Add<Output=T>> Add for Point<T> {
+/// impl<T: Add<Output = T>> Add for Point<T> {
 ///     type Output = Point<T>;
 ///
 ///     fn add(self, other: Point<T>) -> Point<T> {
@@ -157,7 +157,7 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 /// }
 ///
 /// // Notice that the implementation uses the associated type `Output`.
-/// impl<T: Sub<Output=T>> Sub for Point<T> {
+/// impl<T: Sub<Output = T>> Sub for Point<T> {
 ///     type Output = Point<T>;
 ///
 ///     fn sub(self, other: Point<T>) -> Point<T> {
diff --git a/src/libcore/ops/range.rs b/src/libcore/ops/range.rs
index 815a4cfeed8..b3dd5d20299 100644
--- a/src/libcore/ops/range.rs
+++ b/src/libcore/ops/range.rs
@@ -52,7 +52,7 @@ impl fmt::Debug for RangeFull {
 /// (`start..end`).
 ///
 /// The `Range` `start..end` contains all values with `x >= start` and
-/// `x < end`.  It is empty unless `start < end`.
+/// `x < end`. It is empty unless `start < end`.
 ///
 /// # Examples
 ///
@@ -297,7 +297,7 @@ impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
 /// A range bounded inclusively below and above (`start..=end`).
 ///
 /// The `RangeInclusive` `start..=end` contains all values with `x >= start`
-/// and `x <= end`.  It is empty unless `start <= end`.
+/// and `x <= end`. It is empty unless `start <= end`.
 ///
 /// This iterator is [fused], but the specific values of `start` and `end` after
 /// iteration has finished are **unspecified** other than that [`.is_empty()`]
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 0e54397db02..76ef36ac309 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -214,7 +214,7 @@ impl<T> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, preserving the original.
+    /// Converts an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, preserving the original.
     /// The [`map`] method takes the `self` argument by value, consuming the original,
     /// so this technique uses `as_ref` to first take an `Option` to a reference
     /// to the value inside the original.
@@ -395,7 +395,7 @@ impl<T> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, consuming the original:
+    /// Converts an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, consuming the original:
     ///
     /// [`String`]: ../../std/string/struct.String.html
     /// [`usize`]: ../../std/primitive.usize.html
@@ -963,7 +963,7 @@ impl<T: Default> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert a string to an integer, turning poorly-formed strings
+    /// Converts a string to an integer, turning poorly-formed strings
     /// into 0 (the default value for integers). [`parse`] converts
     /// a string to any other type that implements [`FromStr`], returning
     /// [`None`] on error.
diff --git a/src/libcore/pin.rs b/src/libcore/pin.rs
index 56a32c928fb..ee9098d73ee 100644
--- a/src/libcore/pin.rs
+++ b/src/libcore/pin.rs
@@ -199,7 +199,7 @@ impl<P: Deref> Pin<P> {
         Pin { pointer }
     }
 
-    /// Get a pinned shared reference from this pinned pointer.
+    /// Gets a pinned shared reference from this pinned pointer.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn as_ref(self: &Pin<P>) -> Pin<&P::Target> {
@@ -208,7 +208,7 @@ impl<P: Deref> Pin<P> {
 }
 
 impl<P: DerefMut> Pin<P> {
-    /// Get a pinned mutable reference from this pinned pointer.
+    /// Gets a pinned mutable reference from this pinned pointer.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn as_mut(self: &mut Pin<P>) -> Pin<&mut P::Target> {
@@ -247,7 +247,7 @@ impl<'a, T: ?Sized> Pin<&'a T> {
         Pin::new_unchecked(new_pointer)
     }
 
-    /// Get a shared reference out of a pin.
+    /// Gets a shared reference out of a pin.
     ///
     /// Note: `Pin` also implements `Deref` to the target, which can be used
     /// to access the inner value. However, `Deref` only provides a reference
@@ -262,14 +262,14 @@ impl<'a, T: ?Sized> Pin<&'a T> {
 }
 
 impl<'a, T: ?Sized> Pin<&'a mut T> {
-    /// Convert this `Pin<&mut T>` into a `Pin<&T>` with the same lifetime.
+    /// Converts this `Pin<&mut T>` into a `Pin<&T>` with the same lifetime.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn into_ref(self: Pin<&'a mut T>) -> Pin<&'a T> {
         Pin { pointer: self.pointer }
     }
 
-    /// Get a mutable reference to the data inside of this `Pin`.
+    /// Gets a mutable reference to the data inside of this `Pin`.
     ///
     /// This requires that the data inside this `Pin` is `Unpin`.
     ///
@@ -286,7 +286,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
         self.pointer
     }
 
-    /// Get a mutable reference to the data inside of this `Pin`.
+    /// Gets a mutable reference to the data inside of this `Pin`.
     ///
     /// # Safety
     ///
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index 20960845718..866c8d0896b 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -825,7 +825,7 @@ pub unsafe fn write_unaligned<T>(dst: *mut T, src: T) {
 ///
 /// The compiler shouldn't change the relative order or number of volatile
 /// memory operations. However, volatile memory operations on zero-sized types
-/// (e.g., if a zero-sized type is passed to `read_volatile`) are no-ops
+/// (e.g., if a zero-sized type is passed to `read_volatile`) are noops
 /// and may be ignored.
 ///
 /// [c11]: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
@@ -903,7 +903,7 @@ pub unsafe fn read_volatile<T>(src: *const T) -> T {
 ///
 /// The compiler shouldn't change the relative order or number of volatile
 /// memory operations. However, volatile memory operations on zero-sized types
-/// (e.g., if a zero-sized type is passed to `write_volatile`) are no-ops
+/// (e.g., if a zero-sized type is passed to `write_volatile`) are noops
 /// and may be ignored.
 ///
 /// [c11]: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
@@ -2473,7 +2473,7 @@ impl<T: ?Sized> PartialEq for *mut T {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> Eq for *mut T {}
 
-/// Compare raw pointers for equality.
+/// Compares raw pointers for equality.
 ///
 /// This is the same as using the `==` operator, but less generic:
 /// the arguments have to be `*const T` raw pointers,
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index 1ebf0714e23..92d29f6ee8a 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -896,7 +896,7 @@ impl<T: Default, E> Result<T, E> {
     ///
     /// # Examples
     ///
-    /// Convert a string to an integer, turning poorly-formed strings
+    /// Converts a string to an integer, turning poorly-formed strings
     /// into 0 (the default value for integers). [`parse`] converts
     /// a string to any other type that implements [`FromStr`], returning an
     /// [`Err`] on error.
diff --git a/src/libcore/slice/memchr.rs b/src/libcore/slice/memchr.rs
index 312838a170c..cbba546b8da 100644
--- a/src/libcore/slice/memchr.rs
+++ b/src/libcore/slice/memchr.rs
@@ -11,7 +11,7 @@ const HI_U64: u64 = 0x8080808080808080;
 const LO_USIZE: usize = LO_U64 as usize;
 const HI_USIZE: usize = HI_U64 as usize;
 
-/// Returns whether `x` contains any zero byte.
+/// Returns `true` if `x` contains any zero byte.
 ///
 /// From *Matters Computational*, J. Arndt:
 ///
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index e2129c68e7f..acca9748372 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -4123,7 +4123,7 @@ pub struct ChunksExact<'a, T:'a> {
 }
 
 impl<'a, T> ChunksExact<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "chunks_exact", since = "1.31.0")]
@@ -4247,7 +4247,7 @@ pub struct ChunksExactMut<'a, T:'a> {
 }
 
 impl<'a, T> ChunksExactMut<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "chunks_exact", since = "1.31.0")]
@@ -4619,7 +4619,7 @@ pub struct RChunksExact<'a, T:'a> {
 }
 
 impl<'a, T> RChunksExact<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4744,7 +4744,7 @@ pub struct RChunksExactMut<'a, T:'a> {
 }
 
 impl<'a, T> RChunksExactMut<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "rchunks", since = "1.31.0")]
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index c43db916888..6c08e545c5c 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -226,7 +226,7 @@ impl Utf8Error {
     #[stable(feature = "utf8_error", since = "1.5.0")]
     pub fn valid_up_to(&self) -> usize { self.valid_up_to }
 
-    /// Provide more information about the failure:
+    /// Provides more information about the failure:
     ///
     /// * `None`: the end of the input was reached unexpectedly.
     ///   `self.valid_up_to()` is 1 to 3 bytes from the end of the input.
@@ -3504,7 +3504,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `start` in this context means the first
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be left side; and for right-to-left languages like
+    /// Russian, this will be left side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
@@ -3541,7 +3541,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `end` in this context means the last
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be right side; and for right-to-left languages like
+    /// Russian, this will be right side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
@@ -3787,7 +3787,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `start` in this context means the first
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be left side; and for right-to-left languages like
+    /// Russian, this will be left side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
@@ -3819,7 +3819,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `end` in this context means the last
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be right side; and for right-to-left languages like
+    /// Russian, this will be right side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
diff --git a/src/libcore/str/pattern.rs b/src/libcore/str/pattern.rs
index e5a75cdbbcc..2571780ad0b 100644
--- a/src/libcore/str/pattern.rs
+++ b/src/libcore/str/pattern.rs
@@ -117,7 +117,7 @@ pub unsafe trait Searcher<'a> {
     /// `[Reject(0, 1), Reject(1, 2), Match(2, 5), Reject(5, 8)]`
     fn next(&mut self) -> SearchStep;
 
-    /// Find the next `Match` result. See `next()`
+    /// Finds the next `Match` result. See `next()`
     ///
     /// Unlike next(), there is no guarantee that the returned ranges
     /// of this and next_reject will overlap. This will return (start_match, end_match),
@@ -134,7 +134,7 @@ pub unsafe trait Searcher<'a> {
         }
     }
 
-    /// Find the next `Reject` result. See `next()` and `next_match()`
+    /// Finds the next `Reject` result. See `next()` and `next_match()`
     ///
     /// Unlike next(), there is no guarantee that the returned ranges
     /// of this and next_match will overlap.
@@ -185,7 +185,7 @@ pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
     /// `[Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)]`
     fn next_back(&mut self) -> SearchStep;
 
-    /// Find the next `Match` result. See `next_back()`
+    /// Finds the next `Match` result. See `next_back()`
     #[inline]
     fn next_match_back(&mut self) -> Option<(usize, usize)>{
         loop {
@@ -197,7 +197,7 @@ pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
         }
     }
 
-    /// Find the next `Reject` result. See `next_back()`
+    /// Finds the next `Reject` result. See `next_back()`
     #[inline]
     fn next_reject_back(&mut self) -> Option<(usize, usize)>{
         loop {
diff --git a/src/libcore/task/poll.rs b/src/libcore/task/poll.rs
index ac656153519..c811f96ace3 100644
--- a/src/libcore/task/poll.rs
+++ b/src/libcore/task/poll.rs
@@ -22,7 +22,7 @@ pub enum Poll<T> {
 }
 
 impl<T> Poll<T> {
-    /// Change the ready value of this `Poll` with the closure provided
+    /// Changes the ready value of this `Poll` with the closure provided.
     pub fn map<U, F>(self, f: F) -> Poll<U>
         where F: FnOnce(T) -> U
     {
@@ -32,7 +32,7 @@ impl<T> Poll<T> {
         }
     }
 
-    /// Returns whether this is `Poll::Ready`
+    /// Returns `true` if this is `Poll::Ready`
     #[inline]
     pub fn is_ready(&self) -> bool {
         match *self {
@@ -41,7 +41,7 @@ impl<T> Poll<T> {
         }
     }
 
-    /// Returns whether this is `Poll::Pending`
+    /// Returns `true` if this is `Poll::Pending`
     #[inline]
     pub fn is_pending(&self) -> bool {
         !self.is_ready()
@@ -49,7 +49,7 @@ impl<T> Poll<T> {
 }
 
 impl<T, E> Poll<Result<T, E>> {
-    /// Change the success value of this `Poll` with the closure provided
+    /// Changes the success value of this `Poll` with the closure provided.
     pub fn map_ok<U, F>(self, f: F) -> Poll<Result<U, E>>
         where F: FnOnce(T) -> U
     {
@@ -60,7 +60,7 @@ impl<T, E> Poll<Result<T, E>> {
         }
     }
 
-    /// Change the error value of this `Poll` with the closure provided
+    /// Changes the error value of this `Poll` with the closure provided.
     pub fn map_err<U, F>(self, f: F) -> Poll<Result<T, U>>
         where F: FnOnce(E) -> U
     {
diff --git a/src/libcore/task/wake.rs b/src/libcore/task/wake.rs
index 3f7098f1ef9..6d54989706c 100644
--- a/src/libcore/task/wake.rs
+++ b/src/libcore/task/wake.rs
@@ -41,11 +41,11 @@ impl Waker {
         unsafe { self.inner.as_ref().wake() }
     }
 
-    /// Returns whether or not this `Waker` and `other` awaken the same task.
+    /// Returns `true` if or not this `Waker` and `other` awaken the same task.
     ///
     /// This function works on a best-effort basis, and may return false even
     /// when the `Waker`s would awaken the same task. However, if this function
-    /// returns true, it is guaranteed that the `Waker`s will awaken the same
+    /// returns `true`, it is guaranteed that the `Waker`s will awaken the same
     /// task.
     ///
     /// This function is primarily used for optimization purposes.
@@ -54,7 +54,7 @@ impl Waker {
         self.inner == other.inner
     }
 
-    /// Returns whether or not this `Waker` and `other` `LocalWaker` awaken
+    /// Returns `true` if or not this `Waker` and `other` `LocalWaker` awaken
     /// the same task.
     ///
     /// This function works on a best-effort basis, and may return false even
@@ -150,7 +150,7 @@ impl LocalWaker {
         unsafe { self.0.inner.as_ref().wake_local() }
     }
 
-    /// Returns whether or not this `LocalWaker` and `other` `LocalWaker` awaken the same task.
+    /// Returns `true` if or not this `LocalWaker` and `other` `LocalWaker` awaken the same task.
     ///
     /// This function works on a best-effort basis, and may return false even
     /// when the `LocalWaker`s would awaken the same task. However, if this function
@@ -163,7 +163,7 @@ impl LocalWaker {
         self.0.will_wake(&other.0)
     }
 
-    /// Returns whether or not this `LocalWaker` and `other` `Waker` awaken the same task.
+    /// Returns `true` if or not this `LocalWaker` and `other` `Waker` awaken the same task.
     ///
     /// This function works on a best-effort basis, and may return false even
     /// when the `Waker`s would awaken the same task. However, if this function
@@ -223,14 +223,14 @@ pub unsafe trait UnsafeWake: Send + Sync {
     /// Drops this instance of `UnsafeWake`, deallocating resources
     /// associated with it.
     ///
-    /// FIXME(cramertj)
+    // FIXME(cramertj):
     /// This method is intended to have a signature such as:
     ///
     /// ```ignore (not-a-doctest)
     /// fn drop_raw(self: *mut Self);
     /// ```
     ///
-    /// Unfortunately in Rust today that signature is not object safe.
+    /// Unfortunately, in Rust today that signature is not object safe.
     /// Nevertheless it's recommended to implement this function *as if* that
     /// were its signature. As such it is not safe to call on an invalid
     /// pointer, nor is the validity of the pointer guaranteed after this
diff --git a/src/libcore/tests/iter.rs b/src/libcore/tests/iter.rs
index 9b4c78f8d3b..51a6017de1b 100644
--- a/src/libcore/tests/iter.rs
+++ b/src/libcore/tests/iter.rs
@@ -881,7 +881,7 @@ fn test_iterator_flat_map() {
     assert_eq!(i, ys.len());
 }
 
-/// Test `FlatMap::fold` with items already picked off the front and back,
+/// Tests `FlatMap::fold` with items already picked off the front and back,
 /// to make sure all parts of the `FlatMap` are folded correctly.
 #[test]
 fn test_iterator_flat_map_fold() {
@@ -919,7 +919,7 @@ fn test_iterator_flatten() {
     assert_eq!(i, ys.len());
 }
 
-/// Test `Flatten::fold` with items already picked off the front and back,
+/// Tests `Flatten::fold` with items already picked off the front and back,
 /// to make sure all parts of the `Flatten` are folded correctly.
 #[test]
 fn test_iterator_flatten_fold() {
diff --git a/src/libcore/time.rs b/src/libcore/time.rs
index ee583c829dd..ac7e11754aa 100644
--- a/src/libcore/time.rs
+++ b/src/libcore/time.rs
@@ -515,7 +515,7 @@ impl Duration {
         }
     }
 
-    /// Multiply `Duration` by `f64`.
+    /// Multiplies `Duration` by `f64`.
     ///
     /// # Panics
     /// This method will panic if result is not finite, negative or overflows `Duration`.