Export of internal Abseil changes.

--
ee19e203eca970ff88e8f25ce4e19c32e143b988 by Jon Cohen <cohenjon@google.com>:

Exception safety testing no longer uses absl::optional

PiperOrigin-RevId: 220336204

--
460666eb0b316a8b4aeedc589644d53b05251bd1 by Derek Mauro <dmauro@google.com>:

Rework SwissTable SSE2 support
  - Use SSE2 on MSVC when available
    https://github.com/abseil/abseil-cpp/issues/210
  - Emulate _mm_cmpgt_epi8 with other SSE2 instructions when using
    -funsigned-char under GCC
    https://github.com/abseil/abseil-cpp/issues/209

PiperOrigin-RevId: 220312351

--
1f4318ecedf8d539b7b698eb803d613ad6b69278 by Abseil Team <absl-team@google.com>:

Change CollectPerfectRatios to use 10 trials to smooth out the outliers in the
sample.

PiperOrigin-RevId: 220286579

--
6755abc2673553a7f578bb29c6e9ca8d991bc9c8 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 220274307

--
8645b6187329ebf0aaf3c2de2888ba44466cd879 by Abseil Team <absl-team@google.com>:

* #endif for a header guard should reference the guard macro in a comment

PiperOrigin-RevId: 220206868

--
3987a7ad11319230910931cd2468b60b3fd1b85c by Gennadiy Civil <misterg@google.com>:

Internal Change

PiperOrigin-RevId: 220136674

--
cc908c1db2ee0d4523dc813e33f600583bb986c5 by Abseil Team <absl-team@google.com>:

absl: fix backoff logic in SpinLockWait

There are 3 bugs in loop variable handling:
1. It starts with 0, but AbslInternalSpinLockDelay ignores loop == 0.
So it does not actually wait when it should.
2. loop is incremented after successful state changes,
but it should not (why would be increase backoff delay after that?).
3. loop is incremented after CAS failures,
but it should not (why would be increase backoff delay after that?).

Use the same handling of loop as used in SpinLock.

PiperOrigin-RevId: 220136079

--
a0a1c6ef5910ebd28e07215d7df03cc0da0b3eed by Abseil Team <absl-team@google.com>:

absl: relax unnecessarily strong memory ordering in SpinLock::SlowLock

We don't need to acquire visibility over anything when setting kSpinLockSleeper.
Replace the confusing and unnecessarily strong memory order with relaxed.

PiperOrigin-RevId: 220023380

--
c50858b51af28b9fca1a62616324f85f3e84ea74 by Tom Manshreck <shreck@google.com>:

Update comments in flat_hash_map, node_hash_{set, map} and the containers developer guide

PiperOrigin-RevId: 219938692

--
e87b7d1a5f61e165b1c44d3b16d8d967197cdfce by CJ Johnson <johnsoncj@google.com>:

Rearranges the public methods of InlinedVector and cleans up the comments

PiperOrigin-RevId: 219896257

--
f3234c466f792e0fc4bfd21fc7919dba5e679375 by CJ Johnson <johnsoncj@google.com>:

Adds branch prediction to exceptional early exit cases of inlined vector's API

PiperOrigin-RevId: 219887173

--
4dfccf1a81ca0425912d3da25a8470f78c532ce4 by CJ Johnson <johnsoncj@google.com>:

Fixes the InlinedVector public interface to use the allocator type references instead of assuming the type
Also cleans up some cruft in formatting and comments

PiperOrigin-RevId: 219878876

--
4bb6a2b892abb10bd6a424db7e94ed8640802470 by Tom Manshreck <shreck@google.com>:

Add comments on constructor and assignment operator support to flat_hash_set

PiperOrigin-RevId: 219825338

--
c23f973e2f7f4feea0da36bf8a9c3f8a8954bb74 by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 219823847
GitOrigin-RevId: ee19e203eca970ff88e8f25ce4e19c32e143b988
Change-Id: I288c927ca481dc57340420dbb4c278a05cf15e83

1 files changed, 607 insertions, 546 deletions

diff --git a/absl/container/inlined_vector.h b/absl/container/inlined_vector.h
index 0d773e5a0864..ea8cb02baa61 100644
--- a/absl/container/inlined_vector.h
+++ b/absl/container/inlined_vector.h
@@ -1,4 +1,4 @@
-// Copyright 2017 The Abseil Authors.
+// Copyright 2018 The Abseil Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -64,9 +64,28 @@ namespace absl {
 // size, it will trigger an initial allocation on the heap, and will behave as a
 // `std:vector`. The API of the `absl::InlinedVector` within this file is
 // designed to cover the same API footprint as covered by `std::vector`.
-template <typename T, size_t N, typename A = std::allocator<T> >
+template <typename T, size_t N, typename A = std::allocator<T>>
 class InlinedVector {
-  using AllocatorTraits = std::allocator_traits<A>;
+  constexpr static typename A::size_type inlined_capacity() {
+    return static_cast<typename A::size_type>(N);
+  }
+
+  static_assert(inlined_capacity() > 0, "InlinedVector needs inlined capacity");
+
+  template <typename Iterator>
+  using DisableIfIntegral =
+      absl::enable_if_t<!std::is_integral<Iterator>::value>;
+
+  template <typename Iterator>
+  using EnableIfInputIterator = absl::enable_if_t<std::is_convertible<
+      typename std::iterator_traits<Iterator>::iterator_category,
+      std::input_iterator_tag>::value>;
+
+  template <typename Iterator>
+  using IteratorCategory =
+      typename std::iterator_traits<Iterator>::iterator_category;
+
+  using rvalue_reference = typename A::value_type&&;
 
  public:
   using allocator_type = A;
@@ -82,51 +101,61 @@ class InlinedVector {
   using reverse_iterator = std::reverse_iterator<iterator>;
   using const_reverse_iterator = std::reverse_iterator<const_iterator>;
 
+
+  // ---------------------------------------------------------------------------
+  // InlinedVector Constructors and Destructor
+  // ---------------------------------------------------------------------------
+
+  // Creates an empty inlined vector with a default initialized allocator.
   InlinedVector() noexcept(noexcept(allocator_type()))
       : allocator_and_tag_(allocator_type()) {}
 
+  // Creates an empty inlined vector with a specified allocator.
   explicit InlinedVector(const allocator_type& alloc) noexcept
       : allocator_and_tag_(alloc) {}
 
-  // Create a vector with n copies of value_type().
+  // Creates an inlined vector with `n` copies of `value_type()`.
   explicit InlinedVector(size_type n,
                          const allocator_type& alloc = allocator_type())
       : allocator_and_tag_(alloc) {
     InitAssign(n);
   }
 
-  // Create a vector with n copies of elem
-  InlinedVector(size_type n, const value_type& elem,
+  // Creates an inlined vector with `n` copies of `v`.
+  InlinedVector(size_type n, const_reference v,
                 const allocator_type& alloc = allocator_type())
       : allocator_and_tag_(alloc) {
-    InitAssign(n, elem);
+    InitAssign(n, v);
   }
 
-  // Create and initialize with the elements [first .. last).
-  // The unused enable_if argument restricts this constructor so that it is
-  // elided when value_type is an integral type.  This prevents ambiguous
-  // interpretation between a call to this constructor with two integral
-  // arguments and a call to the preceding (n, elem) constructor.
-  template <typename InputIterator>
-  InlinedVector(
-      InputIterator first, InputIterator last,
-      const allocator_type& alloc = allocator_type(),
-      typename std::enable_if<!std::is_integral<InputIterator>::value>::type* =
-          nullptr)
+  // Creates an inlined vector of copies of the values in `init_list`.
+  InlinedVector(std::initializer_list<value_type> init_list,
+                const allocator_type& alloc = allocator_type())
       : allocator_and_tag_(alloc) {
-    AppendRange(first, last);
+    AppendRange(init_list.begin(), init_list.end());
   }
 
-  InlinedVector(std::initializer_list<value_type> init,
+  // Creates and initialize with the elements [`first`, `last`).
+  //
+  // NOTE: The `enable_if` prevents ambiguous interpretation between a call to
+  // this constructor with two integral arguments and a call to the preceding
+  // `InlinedVector(n, v)` constructor.
+  template <typename InputIterator, DisableIfIntegral<InputIterator>* = nullptr>
+  InlinedVector(InputIterator first, InputIterator last,
                 const allocator_type& alloc = allocator_type())
       : allocator_and_tag_(alloc) {
-    AppendRange(init.begin(), init.end());
+    AppendRange(first, last);
   }
 
-  InlinedVector(const InlinedVector& v);
-  InlinedVector(const InlinedVector& v, const allocator_type& alloc);
+  // Creates a copy of `other` using `other`'s allocator.
+  InlinedVector(const InlinedVector& other);
 
-  // This move constructor does not allocate and only moves the underlying
+  // Creates a copy of `other` but with a specified allocator.
+  InlinedVector(const InlinedVector& other, const allocator_type& alloc);
+
+  // Creates an inlined vector with the contents of `other`.
+  //
+  // NOTE: This move constructor does not allocate and only moves the underlying
   // objects, so its `noexcept` specification depends on whether moving the
   // underlying objects can throw or not. We assume
   //  a) move constructors should only throw due to allocation failure and
@@ -138,408 +167,422 @@ class InlinedVector {
       absl::allocator_is_nothrow<allocator_type>::value ||
       std::is_nothrow_move_constructible<value_type>::value);
 
-  // This move constructor allocates and also moves the underlying objects, so
-  // its `noexcept` specification depends on whether the allocation can throw
-  // and whether moving the underlying objects can throw. Based on the same
-  // assumptions above, the `noexcept` specification is dominated by whether the
-  // allocation can throw regardless of whether `value_type`'s move constructor
-  // is specified as `noexcept`.
+  // Creates an inlined vector with the contents of `other`.
+  //
+  // NOTE: This move constructor allocates and also moves the underlying
+  // objects, so its `noexcept` specification depends on whether the allocation
+  // can throw and whether moving the underlying objects can throw. Based on the
+  // same assumptions as above, the `noexcept` specification is dominated by
+  // whether the allocation can throw regardless of whether `value_type`'s move
+  // constructor is specified as `noexcept`.
   InlinedVector(InlinedVector&& v, const allocator_type& alloc) noexcept(
       absl::allocator_is_nothrow<allocator_type>::value);
 
   ~InlinedVector() { clear(); }
 
-  InlinedVector& operator=(const InlinedVector& v) {
-    if (this == &v) {
-      return *this;
-    }
-    // Optimized to avoid reallocation.
-    // Prefer reassignment to copy construction for elements.
-    if (size() < v.size()) {  // grow
-      reserve(v.size());
-      std::copy(v.begin(), v.begin() + size(), begin());
-      std::copy(v.begin() + size(), v.end(), std::back_inserter(*this));
-    } else {  // maybe shrink
-      erase(begin() + v.size(), end());
-      std::copy(v.begin(), v.end(), begin());
-    }
-    return *this;
-  }
-
-  InlinedVector& operator=(InlinedVector&& v) {
-    if (this == &v) {
-      return *this;
-    }
-    if (v.allocated()) {
-      clear();
-      tag().set_allocated_size(v.size());
-      init_allocation(v.allocation());
-      v.tag() = Tag();
-    } else {
-      if (allocated()) clear();
-      // Both are inlined now.
-      if (size() < v.size()) {
-        auto mid = std::make_move_iterator(v.begin() + size());
-        std::copy(std::make_move_iterator(v.begin()), mid, begin());
-        UninitializedCopy(mid, std::make_move_iterator(v.end()), end());
-      } else {
-        auto new_end = std::copy(std::make_move_iterator(v.begin()),
-                                 std::make_move_iterator(v.end()), begin());
-        Destroy(new_end, end());
-      }
-      tag().set_inline_size(v.size());
-    }
-    return *this;
-  }
 
-  InlinedVector& operator=(std::initializer_list<value_type> init) {
-    AssignRange(init.begin(), init.end());
-    return *this;
-  }
+  // ---------------------------------------------------------------------------
+  // InlinedVector Member Accessors
+  // ---------------------------------------------------------------------------
 
-  // InlinedVector::assign()
+  // `InlinedVector::empty()`
   //
-  // Replaces the contents of the inlined vector with copies of those in the
-  // iterator range [first, last).
-  template <typename InputIterator>
-  void assign(
-      InputIterator first, InputIterator last,
-      typename std::enable_if<!std::is_integral<InputIterator>::value>::type* =
-          nullptr) {
-    AssignRange(first, last);
-  }
-
-  // Overload of `InlinedVector::assign()` to take values from elements of an
-  // initializer list
-  void assign(std::initializer_list<value_type> init) {
-    AssignRange(init.begin(), init.end());
-  }
-
-  // Overload of `InlinedVector::assign()` to replace the first `n` elements of
-  // the inlined vector with `elem` values.
-  void assign(size_type n, const value_type& elem) {
-    if (n <= size()) {  // Possibly shrink
-      std::fill_n(begin(), n, elem);
-      erase(begin() + n, end());
-      return;
-    }
-    // Grow
-    reserve(n);
-    std::fill_n(begin(), size(), elem);
-    if (allocated()) {
-      UninitializedFill(allocated_space() + size(), allocated_space() + n,
-                        elem);
-      tag().set_allocated_size(n);
-    } else {
-      UninitializedFill(inlined_space() + size(), inlined_space() + n, elem);
-      tag().set_inline_size(n);
-    }
-  }
+  // Checks if the inlined vector has no elements.
+  bool empty() const noexcept { return !size(); }
 
-  // InlinedVector::size()
+  // `InlinedVector::size()`
   //
   // Returns the number of elements in the inlined vector.
   size_type size() const noexcept { return tag().size(); }
 
-  // InlinedVector::empty()
-  //
-  // Checks if the inlined vector has no elements.
-  bool empty() const noexcept { return (size() == 0); }
-
-  // InlinedVector::capacity()
-  //
-  // Returns the number of elements that can be stored in an inlined vector
-  // without requiring a reallocation of underlying memory. Note that for
-  // most inlined vectors, `capacity()` should equal its initial size `N`; for
-  // inlined vectors which exceed this capacity, they will no longer be inlined,
-  // and `capacity()` will equal its capacity on the allocated heap.
-  size_type capacity() const noexcept {
-    return allocated() ? allocation().capacity() : N;
-  }
-
-  // InlinedVector::max_size()
+  // `InlinedVector::max_size()`
   //
   // Returns the maximum number of elements the vector can hold.
   size_type max_size() const noexcept {
     // One bit of the size storage is used to indicate whether the inlined
-    // vector is allocated; as a result, the maximum size of the container that
-    // we can express is half of the max for our size type.
+    // vector is allocated. As a result, the maximum size of the container that
+    // we can express is half of the max for `size_type`.
     return (std::numeric_limits<size_type>::max)() / 2;
   }
 
-  // InlinedVector::data()
+  // `InlinedVector::capacity()`
   //
-  // Returns a const T* pointer to elements of the inlined vector. This pointer
-  // can be used to access (but not modify) the contained elements.
-  // Only results within the range `[0,size())` are defined.
-  const_pointer data() const noexcept {
-    return allocated() ? allocated_space() : inlined_space();
+  // Returns the number of elements that can be stored in the inlined vector
+  // without requiring a reallocation of underlying memory.
+  //
+  // NOTE: For most inlined vectors, `capacity()` should equal
+  // `inlined_capacity()`. For inlined vectors which exceed this capacity, they
+  // will no longer be inlined and `capacity()` will equal its capacity on the
+  // allocated heap.
+  size_type capacity() const noexcept {
+    return allocated() ? allocation().capacity() : inlined_capacity();
   }
 
-  // Overload of InlinedVector::data() to return a T* pointer to elements of the
-  // inlined vector. This pointer can be used to access and modify the contained
-  // elements.
+  // `InlinedVector::data()`
+  //
+  // Returns a `pointer` to elements of the inlined vector. This pointer can be
+  // used to access and modify the contained elements.
+  // Only results within the range [`0`, `size()`) are defined.
   pointer data() noexcept {
     return allocated() ? allocated_space() : inlined_space();
   }
 
-  // InlinedVector::clear()
-  //
-  // Removes all elements from the inlined vector.
-  void clear() noexcept {
-    size_type s = size();
-    if (allocated()) {
-      Destroy(allocated_space(), allocated_space() + s);
-      allocation().Dealloc(allocator());
-    } else if (s != 0) {  // do nothing for empty vectors
-      Destroy(inlined_space(), inlined_space() + s);
-    }
-    tag() = Tag();
+  // Overload of `InlinedVector::data()` to return a `const_pointer` to elements
+  // of the inlined vector. This pointer can be used to access (but not modify)
+  // the contained elements.
+  const_pointer data() const noexcept {
+    return allocated() ? allocated_space() : inlined_space();
   }
 
-  // InlinedVector::at()
+  // `InlinedVector::operator[]()`
   //
-  // Returns the ith element of an inlined vector.
-  const value_type& at(size_type i) const {
-    if (ABSL_PREDICT_FALSE(i >= size())) {
-      base_internal::ThrowStdOutOfRange(
-          "InlinedVector::at failed bounds check");
-    }
+  // Returns a `reference` to the `i`th element of the inlined vector using the
+  // array operator.
+  reference operator[](size_type i) {
+    assert(i < size());
     return data()[i];
   }
 
-  // InlinedVector::operator[]
-  //
-  // Returns the ith element of an inlined vector using the array operator.
-  const value_type& operator[](size_type i) const {
+  // Overload of `InlinedVector::operator[]()` to return a `const_reference` to
+  // the `i`th element of the inlined vector.
+  const_reference operator[](size_type i) const {
     assert(i < size());
     return data()[i];
   }
 
-  // Overload of InlinedVector::at() to return the ith element of an inlined
-  // vector.
-  value_type& at(size_type i) {
-    if (i >= size()) {
+  // `InlinedVector::at()`
+  //
+  // Returns a `reference` to the `i`th element of the inlined vector.
+  reference at(size_type i) {
+    if (ABSL_PREDICT_FALSE(i >= size())) {
       base_internal::ThrowStdOutOfRange(
-          "InlinedVector::at failed bounds check");
+          "InlinedVector::at() failed bounds check");
     }
     return data()[i];
   }
 
-  // Overload of InlinedVector::operator[] to return the ith element of an
-  // inlined vector.
-  value_type& operator[](size_type i) {
-    assert(i < size());
+  // Overload of `InlinedVector::at()` to return a `const_reference` to the
+  // `i`th element of the inlined vector.
+  const_reference at(size_type i) const {
+    if (ABSL_PREDICT_FALSE(i >= size())) {
+      base_internal::ThrowStdOutOfRange(
+          "InlinedVector::at() failed bounds check");
+    }
     return data()[i];
   }
 
-  // InlinedVector::back()
-  //
-  // Returns a reference to the last element of an inlined vector.
-  value_type& back() {
-    assert(!empty());
-    return at(size() - 1);
-  }
-
-  // Overload of InlinedVector::back() returns a reference to the last element
-  // of an inlined vector of const values.
-  const value_type& back() const {
-    assert(!empty());
-    return at(size() - 1);
-  }
-
-  // InlinedVector::front()
+  // `InlinedVector::front()`
   //
-  // Returns a reference to the first element of an inlined vector.
-  value_type& front() {
+  // Returns a `reference` to the first element of the inlined vector.
+  reference front() {
     assert(!empty());
     return at(0);
   }
 
-  // Overload of InlinedVector::front() returns a reference to the first element
-  // of an inlined vector of const values.
-  const value_type& front() const {
+  // Overload of `InlinedVector::front()` returns a `const_reference` to the
+  // first element of the inlined vector.
+  const_reference front() const {
     assert(!empty());
     return at(0);
   }
 
-  // InlinedVector::emplace_back()
-  //
-  // Constructs and appends an object to the inlined vector.
+  // `InlinedVector::back()`
   //
-  // Returns a reference to the inserted element.
-  template <typename... Args>
-  value_type& emplace_back(Args&&... args) {
-    size_type s = size();
-    assert(s <= capacity());
-    if (ABSL_PREDICT_FALSE(s == capacity())) {
-      return GrowAndEmplaceBack(std::forward<Args>(args)...);
-    }
-    assert(s < capacity());
-
-    value_type* space;
-    if (allocated()) {
-      tag().set_allocated_size(s + 1);
-      space = allocated_space();
-    } else {
-      tag().set_inline_size(s + 1);
-      space = inlined_space();
-    }
-    return Construct(space + s, std::forward<Args>(args)...);
+  // Returns a `reference` to the last element of the inlined vector.
+  reference back() {
+    assert(!empty());
+    return at(size() - 1);
   }
 
-  // InlinedVector::push_back()
-  //
-  // Appends a const element to the inlined vector.
-  void push_back(const value_type& t) { emplace_back(t); }
-
-  // Overload of InlinedVector::push_back() to append a move-only element to the
-  // inlined vector.
-  void push_back(value_type&& t) { emplace_back(std::move(t)); }
-
-  // InlinedVector::pop_back()
-  //
-  // Removes the last element (which is destroyed) in the inlined vector.
-  void pop_back() {
+  // Overload of `InlinedVector::back()` to return a `const_reference` to the
+  // last element of the inlined vector.
+  const_reference back() const {
     assert(!empty());
-    size_type s = size();
-    if (allocated()) {
-      Destroy(allocated_space() + s - 1, allocated_space() + s);
-      tag().set_allocated_size(s - 1);
-    } else {
-      Destroy(inlined_space() + s - 1, inlined_space() + s);
-      tag().set_inline_size(s - 1);
-    }
+    return at(size() - 1);
   }
 
-  // InlinedVector::resize()
+  // `InlinedVector::begin()`
   //
-  // Resizes the inlined vector to contain `n` elements. If `n` is smaller than
-  // the inlined vector's current size, extra elements are destroyed. If `n` is
-  // larger than the initial size, new elements are value-initialized.
-  void resize(size_type n);
-
-  // Overload of InlinedVector::resize() to resize the inlined vector to contain
-  // `n` elements. If `n` is larger than the current size, enough copies of
-  // `elem` are appended to increase its size to `n`.
-  void resize(size_type n, const value_type& elem);
-
-  // InlinedVector::begin()
-  //
-  // Returns an iterator to the beginning of the inlined vector.
+  // Returns an `iterator` to the beginning of the inlined vector.
   iterator begin() noexcept { return data(); }
 
-  // Overload of InlinedVector::begin() for returning a const iterator to the
-  // beginning of the inlined vector.
+  // Overload of `InlinedVector::begin()` to return a `const_iterator` to
+  // the beginning of the inlined vector.
   const_iterator begin() const noexcept { return data(); }
 
-  // InlinedVector::cbegin()
-  //
-  // Returns a const iterator to the beginning of the inlined vector.
-  const_iterator cbegin() const noexcept { return begin(); }
-
-  // InlinedVector::end()
+  // `InlinedVector::end()`
   //
-  // Returns an iterator to the end of the inlined vector.
+  // Returns an `iterator` to the end of the inlined vector.
   iterator end() noexcept { return data() + size(); }
 
-  // Overload of InlinedVector::end() for returning a const iterator to the end
-  // of the inlined vector.
+  // Overload of `InlinedVector::end()` to return a `const_iterator` to the
+  // end of the inlined vector.
   const_iterator end() const noexcept { return data() + size(); }
 
-  // InlinedVector::cend()
+  // `InlinedVector::cbegin()`
   //
-  // Returns a const iterator to the end of the inlined vector.
+  // Returns a `const_iterator` to the beginning of the inlined vector.
+  const_iterator cbegin() const noexcept { return begin(); }
+
+  // `InlinedVector::cend()`
+  //
+  // Returns a `const_iterator` to the end of the inlined vector.
   const_iterator cend() const noexcept { return end(); }
 
-  // InlinedVector::rbegin()
+  // `InlinedVector::rbegin()`
   //
-  // Returns a reverse iterator from the end of the inlined vector.
+  // Returns a `reverse_iterator` from the end of the inlined vector.
   reverse_iterator rbegin() noexcept { return reverse_iterator(end()); }
 
-  // Overload of InlinedVector::rbegin() for returning a const reverse iterator
-  // from the end of the inlined vector.
+  // Overload of `InlinedVector::rbegin()` to return a
+  // `const_reverse_iterator` from the end of the inlined vector.
   const_reverse_iterator rbegin() const noexcept {
     return const_reverse_iterator(end());
   }
 
-  // InlinedVector::crbegin()
+  // `InlinedVector::rend()`
   //
-  // Returns a const reverse iterator from the end of the inlined vector.
-  const_reverse_iterator crbegin() const noexcept { return rbegin(); }
-
-  // InlinedVector::rend()
-  //
-  // Returns a reverse iterator from the beginning of the inlined vector.
+  // Returns a `reverse_iterator` from the beginning of the inlined vector.
   reverse_iterator rend() noexcept { return reverse_iterator(begin()); }
 
-  // Overload of InlinedVector::rend() for returning a const reverse iterator
+  // Overload of `InlinedVector::rend()` to return a `const_reverse_iterator`
   // from the beginning of the inlined vector.
   const_reverse_iterator rend() const noexcept {
     return const_reverse_iterator(begin());
   }
 
-  // InlinedVector::crend()
+  // `InlinedVector::crbegin()`
+  //
+  // Returns a `const_reverse_iterator` from the end of the inlined vector.
+  const_reverse_iterator crbegin() const noexcept { return rbegin(); }
+
+  // `InlinedVector::crend()`
   //
-  // Returns a reverse iterator from the beginning of the inlined vector.
+  // Returns a `const_reverse_iterator` from the beginning of the inlined
+  // vector.
   const_reverse_iterator crend() const noexcept { return rend(); }
 
-  // InlinedVector::emplace()
+  // `InlinedVector::get_allocator()`
   //
-  // Constructs and inserts an object to the inlined vector at the given
-  // `position`, returning an iterator pointing to the newly emplaced element.
-  template <typename... Args>
-  iterator emplace(const_iterator position, Args&&... args);
+  // Returns a copy of the allocator of the inlined vector.
+  allocator_type get_allocator() const { return allocator(); }
+
+
+  // ---------------------------------------------------------------------------
+  // InlinedVector Member Mutators
+  // ---------------------------------------------------------------------------
+
+  // `InlinedVector::operator=()`
+  //
+  // Replaces the contents of the inlined vector with copies of the elements in
+  // the provided `std::initializer_list`.
+  InlinedVector& operator=(std::initializer_list<value_type> init_list) {
+    AssignRange(init_list.begin(), init_list.end());
+    return *this;
+  }
+
+  // Overload of `InlinedVector::operator=()` to replace the contents of the
+  // inlined vector with the contents of `other`.
+  InlinedVector& operator=(const InlinedVector& other) {
+    if (ABSL_PREDICT_FALSE(this == &other)) return *this;
+
+    // Optimized to avoid reallocation.
+    // Prefer reassignment to copy construction for elements.
+    if (size() < other.size()) {  // grow
+      reserve(other.size());
+      std::copy(other.begin(), other.begin() + size(), begin());
+      std::copy(other.begin() + size(), other.end(), std::back_inserter(*this));
+    } else {  // maybe shrink
+      erase(begin() + other.size(), end());
+      std::copy(other.begin(), other.end(), begin());
+    }
+    return *this;
+  }
+
+  // Overload of `InlinedVector::operator=()` to replace the contents of the
+  // inlined vector with the contents of `other`.
+  //
+  // NOTE: As a result of calling this overload, `other` may be empty or it's
+  // contents may be left in a moved-from state.
+  InlinedVector& operator=(InlinedVector&& other) {
+    if (ABSL_PREDICT_FALSE(this == &other)) return *this;
+
+    if (other.allocated()) {
+      clear();
+      tag().set_allocated_size(other.size());
+      init_allocation(other.allocation());
+      other.tag() = Tag();
+    } else {
+      if (allocated()) clear();
+      // Both are inlined now.
+      if (size() < other.size()) {
+        auto mid = std::make_move_iterator(other.begin() + size());
+        std::copy(std::make_move_iterator(other.begin()), mid, begin());
+        UninitializedCopy(mid, std::make_move_iterator(other.end()), end());
+      } else {
+        auto new_end = std::copy(std::make_move_iterator(other.begin()),
+                                 std::make_move_iterator(other.end()), begin());
+        Destroy(new_end, end());
+      }
+      tag().set_inline_size(other.size());
+    }
+    return *this;
+  }
+
+  // `InlinedVector::assign()`
+  //
+  // Replaces the contents of the inlined vector with `n` copies of `v`.
+  void assign(size_type n, const_reference v) {
+    if (n <= size()) {  // Possibly shrink
+      std::fill_n(begin(), n, v);
+      erase(begin() + n, end());
+      return;
+    }
+    // Grow
+    reserve(n);
+    std::fill_n(begin(), size(), v);
+    if (allocated()) {
+      UninitializedFill(allocated_space() + size(), allocated_space() + n, v);
+      tag().set_allocated_size(n);
+    } else {
+      UninitializedFill(inlined_space() + size(), inlined_space() + n, v);
+      tag().set_inline_size(n);
+    }
+  }
+
+  // Overload of `InlinedVector::assign()` to replace the contents of the
+  // inlined vector with copies of the values in the provided
+  // `std::initializer_list`.
+  void assign(std::initializer_list<value_type> init_list) {
+    AssignRange(init_list.begin(), init_list.end());
+  }
+
+  // Overload of `InlinedVector::assign()` to replace the contents of the
+  // inlined vector with values constructed from the range [`first`, `last`).
+  template <typename InputIterator, DisableIfIntegral<InputIterator>* = nullptr>
+  void assign(InputIterator first, InputIterator last) {
+    AssignRange(first, last);
+  }
+
+  // `InlinedVector::resize()`
+  //
+  // Resizes the inlined vector to contain `n` elements. If `n` is smaller than
+  // the inlined vector's current size, extra elements are destroyed. If `n` is
+  // larger than the initial size, new elements are value-initialized.
+  void resize(size_type n);
+
+  // Overload of `InlinedVector::resize()` to resize the inlined vector to
+  // contain `n` elements where, if `n` is larger than `size()`, the new values
+  // will be copy-constructed from `v`.
+  void resize(size_type n, const_reference v);
 
-  // InlinedVector::insert()
+  // `InlinedVector::insert()`
   //
-  // Inserts an element of the specified value at `position`, returning an
-  // iterator pointing to the newly inserted element.
-  iterator insert(const_iterator position, const value_type& v) {
+  // Copies `v` into `position`, returning an `iterator` pointing to the newly
+  // inserted element.
+  iterator insert(const_iterator position, const_reference v) {
     return emplace(position, v);
   }
 
-  // Overload of InlinedVector::insert() for inserting an element of the
-  // specified rvalue, returning an iterator pointing to the newly inserted
-  // element.
-  iterator insert(const_iterator position, value_type&& v) {
+  // Overload of `InlinedVector::insert()` for moving `v` into `position`,
+  // returning an iterator pointing to the newly inserted element.
+  iterator insert(const_iterator position, rvalue_reference v) {
     return emplace(position, std::move(v));
   }
 
-  // Overload of InlinedVector::insert() for inserting `n` elements of the
-  // specified value at `position`, returning an iterator pointing to the first
+  // Overload of `InlinedVector::insert()` for inserting `n` contiguous copies
+  // of `v` starting at `position`. Returns an `iterator` pointing to the first
   // of the newly inserted elements.
-  iterator insert(const_iterator position, size_type n, const value_type& v) {
+  iterator insert(const_iterator position, size_type n, const_reference v) {
     return InsertWithCount(position, n, v);
   }
 
-  // Overload of `InlinedVector::insert()` to disambiguate the two
-  // three-argument overloads of `insert()`, returning an iterator pointing to
-  // the first of the newly inserted elements.
+  // Overload of `InlinedVector::insert()` for copying the contents of the
+  // `std::initializer_list` into the vector starting at `position`. Returns an
+  // `iterator` pointing to the first of the newly inserted elements.
+  iterator insert(const_iterator position,
+                  std::initializer_list<value_type> init_list) {
+    return insert(position, init_list.begin(), init_list.end());
+  }
+
+  // Overload of `InlinedVector::insert()` for inserting elements constructed
+  // from the range [`first`, `last`). Returns an `iterator` pointing to the
+  // first of the newly inserted elements.
+  //
+  // NOTE: The `enable_if` is intended to disambiguate the two three-argument
+  // overloads of `insert()`.
   template <typename InputIterator,
-            typename = typename std::enable_if<std::is_convertible<
-                typename std::iterator_traits<InputIterator>::iterator_category,
-                std::input_iterator_tag>::value>::type>
+            typename = EnableIfInputIterator<InputIterator>>
   iterator insert(const_iterator position, InputIterator first,
                   InputIterator last) {
-    using IterType =
-        typename std::iterator_traits<InputIterator>::iterator_category;
-    return InsertWithRange(position, first, last, IterType());
+    return InsertWithRange(position, first, last,
+                           IteratorCategory<InputIterator>());
   }
 
-  // Overload of InlinedVector::insert() for inserting a list of elements at
-  // `position`, returning an iterator pointing to the first of the newly
-  // inserted elements.
-  iterator insert(const_iterator position,
-                  std::initializer_list<value_type> init) {
-    return insert(position, init.begin(), init.end());
+  // `InlinedVector::emplace()`
+  //
+  // Constructs and inserts an object in the inlined vector at the given
+  // `position`, returning an `iterator` pointing to the newly emplaced element.
+  template <typename... Args>
+  iterator emplace(const_iterator position, Args&&... args);
+
+  // `InlinedVector::emplace_back()`
+  //
+  // Constructs and appends a new element to the end of the inlined vector,
+  // returning a `reference` to the emplaced element.
+  template <typename... Args>
+  reference emplace_back(Args&&... args) {
+    size_type s = size();
+    assert(s <= capacity());
+    if (ABSL_PREDICT_FALSE(s == capacity())) {
+      return GrowAndEmplaceBack(std::forward<Args>(args)...);
+    }
+    assert(s < capacity());
+
+    pointer space;
+    if (allocated()) {
+      tag().set_allocated_size(s + 1);
+      space = allocated_space();
+    } else {
+      tag().set_inline_size(s + 1);
+      space = inlined_space();
+    }
+    return Construct(space + s, std::forward<Args>(args)...);
+  }
+
+  // `InlinedVector::push_back()`
+  //
+  // Appends a copy of `v` to the end of the inlined vector.
+  void push_back(const_reference v) { static_cast<void>(emplace_back(v)); }
+
+  // Overload of `InlinedVector::push_back()` for moving `v` into a newly
+  // appended element.
+  void push_back(rvalue_reference v) {
+    static_cast<void>(emplace_back(std::move(v)));
+  }
+
+  // `InlinedVector::pop_back()`
+  //
+  // Destroys the element at the end of the inlined vector and shrinks the size
+  // by `1` (unless the inlined vector is empty, in which case this is a no-op).
+  void pop_back() noexcept {
+    assert(!empty());
+    size_type s = size();
+    if (allocated()) {
+      Destroy(allocated_space() + s - 1, allocated_space() + s);
+      tag().set_allocated_size(s - 1);
+    } else {
+      Destroy(inlined_space() + s - 1, inlined_space() + s);
+      tag().set_inline_size(s - 1);
+    }
   }
 
-  // InlinedVector::erase()
+  // `InlinedVector::erase()`
   //
   // Erases the element at `position` of the inlined vector, returning an
-  // iterator pointing to the following element or the container's end if the
-  // last element was erased.
+  // `iterator` pointing to the first element following the erased element.
+  //
+  // NOTE: May return the end iterator, which is not dereferencable.
   iterator erase(const_iterator position) {
     assert(position >= begin());
     assert(position < end());
@@ -550,23 +593,36 @@ class InlinedVector {
     return pos;
   }
 
-  // Overload of InlinedVector::erase() for erasing all elements in the
-  // iterator range [first, last) in the inlined vector, returning an iterator
-  // pointing to the first element following the range erased, or the
-  // container's end if range included the container's last element.
-  iterator erase(const_iterator first, const_iterator last);
+  // Overload of `InlinedVector::erase()` for erasing all elements in the
+  // range [`from`, `to`) in the inlined vector. Returns an `iterator` pointing
+  // to the first element following the range erased or the end iterator if `to`
+  // was the end iterator.
+  iterator erase(const_iterator from, const_iterator to);
 
-  // InlinedVector::reserve()
+  // `InlinedVector::clear()`
+  //
+  // Destroys all elements in the inlined vector, sets the size of `0` and
+  // deallocates the heap allocation if the inlined vector was allocated.
+  void clear() noexcept {
+    size_type s = size();
+    if (allocated()) {
+      Destroy(allocated_space(), allocated_space() + s);
+      allocation().Dealloc(allocator());
+    } else if (s != 0) {  // do nothing for empty vectors
+      Destroy(inlined_space(), inlined_space() + s);
+    }
+    tag() = Tag();
+  }
+
+  // `InlinedVector::reserve()`
   //
   // Enlarges the underlying representation of the inlined vector so it can hold
   // at least `n` elements. This method does not change `size()` or the actual
   // contents of the vector.
   //
-  // Note that if `n` does not exceed the inlined vector's initial size `N`,
-  // `reserve()` will have no effect; if it does exceed its initial size,
-  // `reserve()` will trigger an initial allocation and move the inlined vector
-  // onto the heap. If the vector already exists on the heap and the requested
-  // size exceeds it, a reallocation will be performed.
+  // NOTE: If `n` does not exceed `capacity()`, `reserve()` will have no
+  // effects. Otherwise, `reserve()` will reallocate, performing an n-time
+  // element-wise move of everything contained.
   void reserve(size_type n) {
     if (n > capacity()) {
       // Make room for new elements
@@ -574,26 +630,25 @@ class InlinedVector {
     }
   }
 
-  // InlinedVector::shrink_to_fit()
+  // `InlinedVector::shrink_to_fit()`
+  //
+  // Reduces memory usage by freeing unused memory. After this call, calls to
+  // `capacity()` will be equal to `(std::max)(inlined_capacity(), size())`.
   //
-  // Reduces memory usage by freeing unused memory.
-  // After this call `capacity()` will be equal to `max(N, size())`.
+  // If `size() <= inlined_capacity()` and the elements are currently stored on
+  // the heap, they will be moved to the inlined storage and the heap memory
+  // will be deallocated.
   //
-  // If `size() <= N` and the elements are currently stored on the heap, they
-  // will be moved to the inlined storage and the heap memory deallocated.
-  // If `size() > N` and `size() < capacity()` the elements will be moved to
-  // a reallocated storage on heap.
+  // If `size() > inlined_capacity()` and `size() < capacity()` the elements
+  // will be moved to a smaller heap allocation.
   void shrink_to_fit() {
     const auto s = size();
-    if (!allocated() || s == capacity()) {
-      // There's nothing to deallocate.
-      return;
-    }
+    if (ABSL_PREDICT_FALSE(!allocated() || s == capacity())) return;
 
-    if (s <= N) {
+    if (s <= inlined_capacity()) {
       // Move the elements to the inlined storage.
-      // We have to do this using a temporary, because inlined_storage and
-      // allocation_storage are in a union field.
+      // We have to do this using a temporary, because `inlined_storage` and
+      // `allocation_storage` are in a union field.
       auto temp = std::move(*this);
       assign(std::make_move_iterator(temp.begin()),
              std::make_move_iterator(temp.end()));
@@ -601,8 +656,8 @@ class InlinedVector {
     }
 
     // Reallocate storage and move elements.
-    // We can't simply use the same approach as above, because assign() would
-    // call into reserve() internally and reserve larger capacity than we need.
+    // We can't simply use the same approach as above, because `assign()` would
+    // call into `reserve()` internally and reserve larger capacity than we need
     Allocation new_allocation(allocator(), s);
     UninitializedCopy(std::make_move_iterator(allocated_space()),
                       std::make_move_iterator(allocated_space() + s),
@@ -610,32 +665,22 @@ class InlinedVector {
     ResetAllocation(new_allocation, s);
   }
 
-  // InlinedVector::swap()
+  // `InlinedVector::swap()`
   //
   // Swaps the contents of this inlined vector with the contents of `other`.
   void swap(InlinedVector& other);
 
-  // InlinedVector::get_allocator()
-  //
-  // Returns the allocator of this inlined vector.
-  allocator_type get_allocator() const { return allocator(); }
-
-  template <typename H>
-  friend H AbslHashValue(H h, const InlinedVector& v) {
-    return H::combine(H::combine_contiguous(std::move(h), v.data(), v.size()),
-                      v.size());
+  template <typename Hash>
+  friend Hash AbslHashValue(Hash hash, const InlinedVector& inlined_vector) {
+    const_pointer p = inlined_vector.data();
+    size_type n = inlined_vector.size();
+    return Hash::combine(Hash::combine_contiguous(std::move(hash), p, n), n);
   }
 
  private:
-  static_assert(N > 0, "inlined vector with nonpositive size");
-
-  // It holds whether the vector is allocated or not in the lowest bit.
-  // The size is held in the high bits:
-  //   size_ = (size << 1) | is_allocated;
-  //
-  // Maintainer's Note: size_type is user defined. The contract is limited to
-  // arithmetic operators to avoid depending on compliant overloaded bitwise
-  // operators.
+  // Holds whether the vector is allocated or not in the lowest bit and the size
+  // in the high bits:
+  //   `size_ = (size << 1) | is_allocated;`
   class Tag {
    public:
     Tag() : size_(0) {}
@@ -649,14 +694,15 @@ class InlinedVector {
     size_type size_;
   };
 
-  // Derives from allocator_type to use the empty base class optimization.
-  // If the allocator_type is stateless, we can 'store'
-  // our instance of it for free.
+  // Derives from `allocator_type` to use the empty base class optimization.
+  // If the `allocator_type` is stateless, we can store our instance for free.
   class AllocatorAndTag : private allocator_type {
    public:
     explicit AllocatorAndTag(const allocator_type& a) : allocator_type(a) {}
+
     Tag& tag() { return tag_; }
     const Tag& tag() const { return tag_; }
+
     allocator_type& allocator() { return *this; }
     const allocator_type& allocator() const { return *this; }
 
@@ -666,68 +712,79 @@ class InlinedVector {
 
   class Allocation {
    public:
-    Allocation(allocator_type& a,  // NOLINT(runtime/references)
-               size_type capacity)
-        : capacity_(capacity),
-          buffer_(AllocatorTraits::allocate(a, capacity_)) {}
+    Allocation(allocator_type& a, size_type capacity)
+        : capacity_(capacity), buffer_(Create(a, capacity)) {}
 
-    void Dealloc(allocator_type& a) {  // NOLINT(runtime/references)
-      AllocatorTraits::deallocate(a, buffer(), capacity());
+    void Dealloc(allocator_type& a) {
+      std::allocator_traits<allocator_type>::deallocate(a, buffer_, capacity_);
     }
 
     size_type capacity() const { return capacity_; }
-    const value_type* buffer() const { return buffer_; }
-    value_type* buffer() { return buffer_; }
+
+    const_pointer buffer() const { return buffer_; }
+
+    pointer buffer() { return buffer_; }
 
    private:
+    static pointer Create(allocator_type& a, size_type n) {
+      return std::allocator_traits<allocator_type>::allocate(a, n);
+    }
+
     size_type capacity_;
-    value_type* buffer_;
+    pointer buffer_;
   };
 
   const Tag& tag() const { return allocator_and_tag_.tag(); }
+
   Tag& tag() { return allocator_and_tag_.tag(); }
 
   Allocation& allocation() {
     return reinterpret_cast<Allocation&>(rep_.allocation_storage.allocation);
   }
+
   const Allocation& allocation() const {
     return reinterpret_cast<const Allocation&>(
         rep_.allocation_storage.allocation);
   }
+
   void init_allocation(const Allocation& allocation) {
     new (&rep_.allocation_storage.allocation) Allocation(allocation);
   }
 
   // TODO(absl-team): investigate whether the reinterpret_cast is appropriate.
-  value_type* inlined_space() {
-    return reinterpret_cast<value_type*>(
+  pointer inlined_space() {
+    return reinterpret_cast<pointer>(
         std::addressof(rep_.inlined_storage.inlined[0]));
   }
-  const value_type* inlined_space() const {
-    return reinterpret_cast<const value_type*>(
+
+  const_pointer inlined_space() const {
+    return reinterpret_cast<const_pointer>(
         std::addressof(rep_.inlined_storage.inlined[0]));
   }
 
-  value_type* allocated_space() { return allocation().buffer(); }
-  const value_type* allocated_space() const { return allocation().buffer(); }
+  pointer allocated_space() { return allocation().buffer(); }
+
+  const_pointer allocated_space() const { return allocation().buffer(); }
 
   const allocator_type& allocator() const {
     return allocator_and_tag_.allocator();
   }
+
   allocator_type& allocator() { return allocator_and_tag_.allocator(); }
 
   bool allocated() const { return tag().allocated(); }
 
-  // Enlarge the underlying representation so we can store size_ + delta elems.
-  // The size is not changed, and any newly added memory is not initialized.
+  // Enlarge the underlying representation so we can store `size_ + delta` elems
+  // in allocated space. The size is not changed, and any newly added memory is
+  // not initialized.
   void EnlargeBy(size_type delta);
 
-  // Shift all elements from position to end() n places to the right.
+  // Shift all elements from `position` to `end()` by `n` places to the right.
   // If the vector needs to be enlarged, memory will be allocated.
-  // Returns iterators pointing to the start of the previously-initialized
+  // Returns `iterator`s pointing to the start of the previously-initialized
   // portion and the start of the uninitialized portion of the created gap.
-  // The number of initialized spots is pair.second - pair.first;
-  // the number of raw spots is n - (pair.second - pair.first).
+  // The number of initialized spots is `pair.second - pair.first`. The number
+  // of raw spots is `n - (pair.second - pair.first)`.
   //
   // Updates the size of the InlinedVector internally.
   std::pair<iterator, iterator> ShiftRight(const_iterator position,
@@ -747,13 +804,13 @@ class InlinedVector {
   }
 
   template <typename... Args>
-  value_type& GrowAndEmplaceBack(Args&&... args) {
+  reference GrowAndEmplaceBack(Args&&... args) {
     assert(size() == capacity());
     const size_type s = size();
 
     Allocation new_allocation(allocator(), 2 * capacity());
 
-    value_type& new_element =
+    reference new_element =
         Construct(new_allocation.buffer() + s, std::forward<Args>(args)...);
     UninitializedCopy(std::make_move_iterator(data()),
                       std::make_move_iterator(data() + s),
@@ -765,98 +822,103 @@ class InlinedVector {
   }
 
   void InitAssign(size_type n);
-  void InitAssign(size_type n, const value_type& t);
+
+  void InitAssign(size_type n, const_reference v);
 
   template <typename... Args>
-  value_type& Construct(pointer p, Args&&... args) {
-    AllocatorTraits::construct(allocator(), p, std::forward<Args>(args)...);
+  reference Construct(pointer p, Args&&... args) {
+    std::allocator_traits<allocator_type>::construct(
+        allocator(), p, std::forward<Args>(args)...);
     return *p;
   }
 
-  template <typename Iter>
-  void UninitializedCopy(Iter src, Iter src_last, value_type* dst) {
+  template <typename Iterator>
+  void UninitializedCopy(Iterator src, Iterator src_last, pointer dst) {
     for (; src != src_last; ++dst, ++src) Construct(dst, *src);
   }
 
   template <typename... Args>
-  void UninitializedFill(value_type* dst, value_type* dst_last,
-                         const Args&... args) {
+  void UninitializedFill(pointer dst, pointer dst_last, const Args&... args) {
     for (; dst != dst_last; ++dst) Construct(dst, args...);
   }
 
-  // Destroy [ptr, ptr_last) in place.
-  void Destroy(value_type* ptr, value_type* ptr_last);
+  // Destroy [`from`, `to`) in place.
+  void Destroy(pointer from, pointer to);
 
-  template <typename Iter>
-  void AppendRange(Iter first, Iter last, std::input_iterator_tag) {
+  template <typename Iterator>
+  void AppendRange(Iterator first, Iterator last, std::input_iterator_tag) {
     std::copy(first, last, std::back_inserter(*this));
   }
 
-  // Faster path for forward iterators.
-  template <typename Iter>
-  void AppendRange(Iter first, Iter last, std::forward_iterator_tag);
+  template <typename Iterator>
+  void AppendRange(Iterator first, Iterator last, std::forward_iterator_tag);
 
-  template <typename Iter>
-  void AppendRange(Iter first, Iter last) {
-    using IterTag = typename std::iterator_traits<Iter>::iterator_category;
-    AppendRange(first, last, IterTag());
+  template <typename Iterator>
+  void AppendRange(Iterator first, Iterator last) {
+    AppendRange(first, last, IteratorCategory<Iterator>());
   }
 
-  template <typename Iter>
-  void AssignRange(Iter first, Iter last, std::input_iterator_tag);
+  template <typename Iterator>
+  void AssignRange(Iterator first, Iterator last, std::input_iterator_tag);
 
-  // Faster path for forward iterators.
-  template <typename Iter>
-  void AssignRange(Iter first, Iter last, std::forward_iterator_tag);
+  template <typename Iterator>
+  void AssignRange(Iterator first, Iterator last, std::forward_iterator_tag);
 
-  template <typename Iter>
-  void AssignRange(Iter first, Iter last) {
-    using IterTag = typename std::iterator_traits<Iter>::iterator_category;
-    AssignRange(first, last, IterTag());
+  template <typename Iterator>
+  void AssignRange(Iterator first, Iterator last) {
+    AssignRange(first, last, IteratorCategory<Iterator>());
   }
 
   iterator InsertWithCount(const_iterator position, size_type n,
-                           const value_type& v);
+                           const_reference v);
 
-  template <typename InputIter>
-  iterator InsertWithRange(const_iterator position, InputIter first,
-                           InputIter last, std::input_iterator_tag);
-  template <typename ForwardIter>
-  iterator InsertWithRange(const_iterator position, ForwardIter first,
-                           ForwardIter last, std::forward_iterator_tag);
+  template <typename InputIterator>
+  iterator InsertWithRange(const_iterator position, InputIterator first,
+                           InputIterator last, std::input_iterator_tag);
 
-  AllocatorAndTag allocator_and_tag_;
+  template <typename ForwardIterator>
+  iterator InsertWithRange(const_iterator position, ForwardIterator first,
+                           ForwardIterator last, std::forward_iterator_tag);
 
-  // Either the inlined or allocated representation
+  // Stores either the inlined or allocated representation
   union Rep {
-    // Use struct to perform indirection that solves a bizarre compilation
-    // error on Visual Studio (all known versions).
-    struct {
-      typename std::aligned_storage<sizeof(value_type),
-                                    alignof(value_type)>::type inlined[N];
-    } inlined_storage;
-    struct {
-      typename std::aligned_storage<sizeof(Allocation),
-                                    alignof(Allocation)>::type allocation;
-    } allocation_storage;
-  } rep_;
+    using ValueTypeBuffer =
+        absl::aligned_storage_t<sizeof(value_type), alignof(value_type)>;
+    using AllocationBuffer =
+        absl::aligned_storage_t<sizeof(Allocation), alignof(Allocation)>;
+
+    // Structs wrap the buffers to perform indirection that solves a bizarre
+    // compilation error on Visual Studio (all known versions).
+    struct InlinedRep {
+      ValueTypeBuffer inlined[inlined_capacity()];
+    };
+    struct AllocatedRep {
+      AllocationBuffer allocation;
+    };
+
+    InlinedRep inlined_storage;
+    AllocatedRep allocation_storage;
+  };
+
+  AllocatorAndTag allocator_and_tag_;
+  Rep rep_;
 };
 
 // -----------------------------------------------------------------------------
 // InlinedVector Non-Member Functions
 // -----------------------------------------------------------------------------
 
-// swap()
+// `swap()`
 //
 // Swaps the contents of two inlined vectors. This convenience function
-// simply calls InlinedVector::swap(other_inlined_vector).
+// simply calls `InlinedVector::swap()`.
 template <typename T, size_t N, typename A>
 void swap(InlinedVector<T, N, A>& a,
           InlinedVector<T, N, A>& b) noexcept(noexcept(a.swap(b))) {
   a.swap(b);
 }
 
-// operator==()
+// `operator==()`
 //
 // Tests the equivalency of the contents of two inlined vectors.
 template <typename T, size_t N, typename A>
@@ -865,7 +927,7 @@ bool operator==(const InlinedVector<T, N, A>& a,
   return absl::equal(a.begin(), a.end(), b.begin(), b.end());
 }
 
-// operator!=()
+// `operator!=()`
 //
 // Tests the inequality of the contents of two inlined vectors.
 template <typename T, size_t N, typename A>
@@ -874,7 +936,7 @@ bool operator!=(const InlinedVector<T, N, A>& a,
   return !(a == b);
 }
 
-// operator<()
+// `operator<()`
 //
 // Tests whether the contents of one inlined vector are less than the contents
 // of another through a lexicographical comparison operation.
@@ -884,7 +946,7 @@ bool operator<(const InlinedVector<T, N, A>& a,
   return std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end());
 }
 
-// operator>()
+// `operator>()`
 //
 // Tests whether the contents of one inlined vector are greater than the
 // contents of another through a lexicographical comparison operation.
@@ -894,7 +956,7 @@ bool operator>(const InlinedVector<T, N, A>& a,
   return b < a;
 }
 
-// operator<=()
+// `operator<=()`
 //
 // Tests whether the contents of one inlined vector are less than or equal to
 // the contents of another through a lexicographical comparison operation.
@@ -904,7 +966,7 @@ bool operator<=(const InlinedVector<T, N, A>& a,
   return !(b < a);
 }
 
-// operator>=()
+// `operator>=()`
 //
 // Tests whether the contents of one inlined vector are greater than or equal to
 // the contents of another through a lexicographical comparison operation.
@@ -916,97 +978,99 @@ bool operator>=(const InlinedVector<T, N, A>& a,
 
 // -----------------------------------------------------------------------------
 // Implementation of InlinedVector
-// -----------------------------------------------------------------------------
 //
-// Do not depend on any implementation details below this line.
+// Do not depend on any below implementation details!
+// -----------------------------------------------------------------------------
 
 template <typename T, size_t N, typename A>
-InlinedVector<T, N, A>::InlinedVector(const InlinedVector& v)
-    : allocator_and_tag_(v.allocator()) {
-  reserve(v.size());
+InlinedVector<T, N, A>::InlinedVector(const InlinedVector& other)
+    : allocator_and_tag_(other.allocator()) {
+  reserve(other.size());
   if (allocated()) {
-    UninitializedCopy(v.begin(), v.end(), allocated_space());
-    tag().set_allocated_size(v.size());
+    UninitializedCopy(other.begin(), other.end(), allocated_space());
+    tag().set_allocated_size(other.size());
   } else {
-    UninitializedCopy(v.begin(), v.end(), inlined_space());
-    tag().set_inline_size(v.size());
+    UninitializedCopy(other.begin(), other.end(), inlined_space());
+    tag().set_inline_size(other.size());
   }
 }
 
 template <typename T, size_t N, typename A>
-InlinedVector<T, N, A>::InlinedVector(const InlinedVector& v,
+InlinedVector<T, N, A>::InlinedVector(const InlinedVector& other,
                                       const allocator_type& alloc)
     : allocator_and_tag_(alloc) {
-  reserve(v.size());
+  reserve(other.size());
   if (allocated()) {
-    UninitializedCopy(v.begin(), v.end(), allocated_space());
-    tag().set_allocated_size(v.size());
+    UninitializedCopy(other.begin(), other.end(), allocated_space());
+    tag().set_allocated_size(other.size());
   } else {
-    UninitializedCopy(v.begin(), v.end(), inlined_space());
-    tag().set_inline_size(v.size());
+    UninitializedCopy(other.begin(), other.end(), inlined_space());
+    tag().set_inline_size(other.size());
   }
 }
 
 template <typename T, size_t N, typename A>
-InlinedVector<T, N, A>::InlinedVector(InlinedVector&& v) noexcept(
+InlinedVector<T, N, A>::InlinedVector(InlinedVector&& other) noexcept(
     absl::allocator_is_nothrow<allocator_type>::value ||
     std::is_nothrow_move_constructible<value_type>::value)
-    : allocator_and_tag_(v.allocator_and_tag_) {
-  if (v.allocated()) {
+    : allocator_and_tag_(other.allocator_and_tag_) {
+  if (other.allocated()) {
     // We can just steal the underlying buffer from the source.
     // That leaves the source empty, so we clear its size.
-    init_allocation(v.allocation());
-    v.tag() = Tag();
+    init_allocation(other.allocation());
+    other.tag() = Tag();
   } else {
-    UninitializedCopy(std::make_move_iterator(v.inlined_space()),
-                      std::make_move_iterator(v.inlined_space() + v.size()),
-                      inlined_space());
+    UninitializedCopy(
+        std::make_move_iterator(other.inlined_space()),
+        std::make_move_iterator(other.inlined_space() + other.size()),
+        inlined_space());
   }
 }
 
 template <typename T, size_t N, typename A>
-InlinedVector<T, N, A>::InlinedVector(
-    InlinedVector&& v,
-    const allocator_type&
-        alloc) noexcept(absl::allocator_is_nothrow<allocator_type>::value)
+InlinedVector<T, N, A>::InlinedVector(InlinedVector&& other,
+                                      const allocator_type& alloc) noexcept(  //
+    absl::allocator_is_nothrow<allocator_type>::value)
     : allocator_and_tag_(alloc) {
-  if (v.allocated()) {
-    if (alloc == v.allocator()) {
+  if (other.allocated()) {
+    if (alloc == other.allocator()) {
       // We can just steal the allocation from the source.
-      tag() = v.tag();
-      init_allocation(v.allocation());
-      v.tag() = Tag();
+      tag() = other.tag();
+      init_allocation(other.allocation());
+      other.tag() = Tag();
     } else {
       // We need to use our own allocator
-      reserve(v.size());
-      UninitializedCopy(std::make_move_iterator(v.begin()),
-                        std::make_move_iterator(v.end()), allocated_space());
-      tag().set_allocated_size(v.size());
+      reserve(other.size());
+      UninitializedCopy(std::make_move_iterator(other.begin()),
+                        std::make_move_iterator(other.end()),
+                        allocated_space());
+      tag().set_allocated_size(other.size());
     }
   } else {
-    UninitializedCopy(std::make_move_iterator(v.inlined_space()),
-                      std::make_move_iterator(v.inlined_space() + v.size()),
-                      inlined_space());
-    tag().set_inline_size(v.size());
+    UninitializedCopy(
+        std::make_move_iterator(other.inlined_space()),
+        std::make_move_iterator(other.inlined_space() + other.size()),
+        inlined_space());
+    tag().set_inline_size(other.size());
   }
 }
 
 template <typename T, size_t N, typename A>
-void InlinedVector<T, N, A>::InitAssign(size_type n, const value_type& t) {
-  if (n > static_cast<size_type>(N)) {
+void InlinedVector<T, N, A>::InitAssign(size_type n, const_reference v) {
+  if (n > inlined_capacity()) {
     Allocation new_allocation(allocator(), n);
     init_allocation(new_allocation);
-    UninitializedFill(allocated_space(), allocated_space() + n, t);
+    UninitializedFill(allocated_space(), allocated_space() + n, v);
     tag().set_allocated_size(n);
   } else {
-    UninitializedFill(inlined_space(), inlined_space() + n, t);
+    UninitializedFill(inlined_space(), inlined_space() + n, v);
     tag().set_inline_size(n);
   }
 }
 
 template <typename T, size_t N, typename A>
 void InlinedVector<T, N, A>::InitAssign(size_type n) {
-  if (n > static_cast<size_type>(N)) {
+  if (n > inlined_capacity()) {
     Allocation new_allocation(allocator(), n);
     init_allocation(new_allocation);
     UninitializedFill(allocated_space(), allocated_space() + n);
@@ -1038,7 +1102,7 @@ void InlinedVector<T, N, A>::resize(size_type n) {
 }
 
 template <typename T, size_t N, typename A>
-void InlinedVector<T, N, A>::resize(size_type n, const value_type& elem) {
+void InlinedVector<T, N, A>::resize(size_type n, const_reference v) {
   size_type s = size();
   if (n < s) {
     erase(begin() + n, end());
@@ -1047,23 +1111,23 @@ void InlinedVector<T, N, A>::resize(size_type n, const value_type& elem) {
   reserve(n);
   assert(capacity() >= n);
 
-  // Fill new space with copies of 'elem'.
+  // Fill new space with copies of 'v'.
   if (allocated()) {
-    UninitializedFill(allocated_space() + s, allocated_space() + n, elem);
+    UninitializedFill(allocated_space() + s, allocated_space() + n, v);
     tag().set_allocated_size(n);
   } else {
-    UninitializedFill(inlined_space() + s, inlined_space() + n, elem);
+    UninitializedFill(inlined_space() + s, inlined_space() + n, v);
     tag().set_inline_size(n);
   }
 }
 
 template <typename T, size_t N, typename A>
 template <typename... Args>
-typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::emplace(
-    const_iterator position, Args&&... args) {
+auto InlinedVector<T, N, A>::emplace(const_iterator position, Args&&... args)
+    -> iterator {
   assert(position >= begin());
   assert(position <= end());
-  if (position == end()) {
+  if (ABSL_PREDICT_FALSE(position == end())) {
     emplace_back(std::forward<Args>(args)...);
     return end() - 1;
   }
@@ -1083,14 +1147,14 @@ typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::emplace(
 }
 
 template <typename T, size_t N, typename A>
-typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::erase(
-    const_iterator first, const_iterator last) {
-  assert(begin() <= first);
-  assert(first <= last);
-  assert(last <= end());
+auto InlinedVector<T, N, A>::erase(const_iterator from, const_iterator to)
+    -> iterator {
+  assert(begin() <= from);
+  assert(from <= to);
+  assert(to <= end());
 
-  iterator range_start = const_cast<iterator>(first);
-  iterator range_end = const_cast<iterator>(last);
+  iterator range_start = const_cast<iterator>(from);
+  iterator range_end = const_cast<iterator>(to);
 
   size_type s = size();
   ptrdiff_t erase_gap = std::distance(range_start, range_end);
@@ -1111,10 +1175,9 @@ typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::erase(
 
 template <typename T, size_t N, typename A>
 void InlinedVector<T, N, A>::swap(InlinedVector& other) {
-  using std::swap;  // Augment ADL with std::swap.
-  if (&other == this) {
-    return;
-  }
+  using std::swap;  // Augment ADL with `std::swap`.
+  if (ABSL_PREDICT_FALSE(this == &other)) return;
+
   if (allocated() && other.allocated()) {
     // Both out of line, so just swap the tag, allocation, and allocator.
     swap(tag(), other.tag());
@@ -1133,11 +1196,12 @@ void InlinedVector<T, N, A>::swap(InlinedVector& other) {
     const size_type a_size = a->size();
     const size_type b_size = b->size();
     assert(a_size >= b_size);
-    // 'a' is larger. Swap the elements up to the smaller array size.
+    // `a` is larger. Swap the elements up to the smaller array size.
     std::swap_ranges(a->inlined_space(), a->inlined_space() + b_size,
                      b->inlined_space());
 
-    // Move the remaining elements: A[b_size,a_size) -> B[b_size,a_size)
+    // Move the remaining elements:
+    //   [`b_size`, `a_size`) from `a` -> [`b_size`, `a_size`) from `b`
     b->UninitializedCopy(a->inlined_space() + b_size,
                          a->inlined_space() + a_size,
                          b->inlined_space() + b_size);
@@ -1149,6 +1213,7 @@ void InlinedVector<T, N, A>::swap(InlinedVector& other) {
     assert(a->size() == b_size);
     return;
   }
+
   // One is out of line, one is inline.
   // We first move the elements from the inlined vector into the
   // inlined space in the other vector.  We then put the other vector's
@@ -1163,13 +1228,13 @@ void InlinedVector<T, N, A>::swap(InlinedVector& other) {
   assert(b->allocated());
   const size_type a_size = a->size();
   const size_type b_size = b->size();
-  // In an optimized build, b_size would be unused.
-  (void)b_size;
+  // In an optimized build, `b_size` would be unused.
+  static_cast<void>(b_size);
 
-  // Made Local copies of size(), don't need tag() accurate anymore
+  // Made Local copies of `size()`, don't need `tag()` accurate anymore
   swap(a->tag(), b->tag());
 
-  // Copy b_allocation out before b's union gets clobbered by inline_space.
+  // Copy `b_allocation` out before `b`'s union gets clobbered by `inline_space`
   Allocation b_allocation = b->allocation();
 
   b->UninitializedCopy(a->inlined_space(), a->inlined_space() + a_size,
@@ -1191,7 +1256,7 @@ void InlinedVector<T, N, A>::EnlargeBy(size_type delta) {
   const size_type s = size();
   assert(s <= capacity());
 
-  size_type target = std::max(static_cast<size_type>(N), s + delta);
+  size_type target = std::max(inlined_capacity(), s + delta);
 
   // Compute new capacity by repeatedly doubling current capacity
   // TODO(psrc): Check and avoid overflow?
@@ -1223,7 +1288,7 @@ auto InlinedVector<T, N, A>::ShiftRight(const_iterator position, size_type n)
     while (new_capacity < required_size) {
       new_capacity <<= 1;
     }
-    // Move everyone into the new allocation, leaving a gap of n for the
+    // Move everyone into the new allocation, leaving a gap of `n` for the
     // requested shift.
     Allocation new_allocation(allocator(), new_capacity);
     size_type index = position - begin();
@@ -1241,8 +1306,8 @@ auto InlinedVector<T, N, A>::ShiftRight(const_iterator position, size_type n)
     start_used = start_raw;
   } else {
     // If we had enough space, it's a two-part move. Elements going into
-    // previously-unoccupied space need an UninitializedCopy. Elements
-    // going into a previously-occupied space are just a move.
+    // previously-unoccupied space need an `UninitializedCopy()`. Elements
+    // going into a previously-occupied space are just a `std::move()`.
     iterator pos = const_cast<iterator>(position);
     iterator raw_space = end();
     size_type slots_in_used_space = raw_space - pos;
@@ -1268,27 +1333,26 @@ auto InlinedVector<T, N, A>::ShiftRight(const_iterator position, size_type n)
 }
 
 template <typename T, size_t N, typename A>
-void InlinedVector<T, N, A>::Destroy(value_type* ptr, value_type* ptr_last) {
-  for (value_type* p = ptr; p != ptr_last; ++p) {
-    AllocatorTraits::destroy(allocator(), p);
+void InlinedVector<T, N, A>::Destroy(pointer from, pointer to) {
+  for (pointer cur = from; cur != to; ++cur) {
+    std::allocator_traits<allocator_type>::destroy(allocator(), cur);
   }
-
-  // Overwrite unused memory with 0xab so we can catch uninitialized usage.
-  // Cast to void* to tell the compiler that we don't care that we might be
-  // scribbling on a vtable pointer.
 #ifndef NDEBUG
-  if (ptr != ptr_last) {
-    memset(reinterpret_cast<void*>(ptr), 0xab, sizeof(*ptr) * (ptr_last - ptr));
+  // Overwrite unused memory with `0xab` so we can catch uninitialized usage.
+  // Cast to `void*` to tell the compiler that we don't care that we might be
+  // scribbling on a vtable pointer.
+  if (from != to) {
+    auto len = sizeof(value_type) * std::distance(from, to);
+    std::memset(reinterpret_cast<void*>(from), 0xab, len);
   }
 #endif
 }
 
 template <typename T, size_t N, typename A>
-template <typename Iter>
-void InlinedVector<T, N, A>::AppendRange(Iter first, Iter last,
+template <typename Iterator>
+void InlinedVector<T, N, A>::AppendRange(Iterator first, Iterator last,
                                          std::forward_iterator_tag) {
-  using Length = typename std::iterator_traits<Iter>::difference_type;
-  Length length = std::distance(first, last);
+  auto length = std::distance(first, last);
   reserve(size() + length);
   if (allocated()) {
     UninitializedCopy(first, last, allocated_space() + size());
@@ -1300,8 +1364,8 @@ void InlinedVector<T, N, A>::AppendRange(Iter first, Iter last,
 }
 
 template <typename T, size_t N, typename A>
-template <typename Iter>
-void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
+template <typename Iterator>
+void InlinedVector<T, N, A>::AssignRange(Iterator first, Iterator last,
                                          std::input_iterator_tag) {
   // Optimized to avoid reallocation.
   // Prefer reassignment to copy construction for elements.
@@ -1314,11 +1378,10 @@ void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
 }
 
 template <typename T, size_t N, typename A>
-template <typename Iter>
-void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
+template <typename Iterator>
+void InlinedVector<T, N, A>::AssignRange(Iterator first, Iterator last,
                                          std::forward_iterator_tag) {
-  using Length = typename std::iterator_traits<Iter>::difference_type;
-  Length length = std::distance(first, last);
+  auto length = std::distance(first, last);
   // Prefer reassignment to copy construction for elements.
   if (static_cast<size_type>(length) <= size()) {
     erase(std::copy(first, last, begin()), end());
@@ -1338,10 +1401,10 @@ void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
 
 template <typename T, size_t N, typename A>
 auto InlinedVector<T, N, A>::InsertWithCount(const_iterator position,
-                                             size_type n, const value_type& v)
+                                             size_type n, const_reference v)
     -> iterator {
   assert(position >= begin() && position <= end());
-  if (n == 0) return const_cast<iterator>(position);
+  if (ABSL_PREDICT_FALSE(n == 0)) return const_cast<iterator>(position);
 
   value_type copy = v;
   std::pair<iterator, iterator> it_pair = ShiftRight(position, n);
@@ -1352,9 +1415,10 @@ auto InlinedVector<T, N, A>::InsertWithCount(const_iterator position,
 }
 
 template <typename T, size_t N, typename A>
-template <typename InputIter>
+template <typename InputIterator>
 auto InlinedVector<T, N, A>::InsertWithRange(const_iterator position,
-                                             InputIter first, InputIter last,
+                                             InputIterator first,
+                                             InputIterator last,
                                              std::input_iterator_tag)
     -> iterator {
   assert(position >= begin() && position <= end());
@@ -1364,23 +1428,20 @@ auto InlinedVector<T, N, A>::InsertWithRange(const_iterator position,
   return begin() + index;
 }
 
-// Overload of InlinedVector::InsertWithRange()
 template <typename T, size_t N, typename A>
-template <typename ForwardIter>
+template <typename ForwardIterator>
 auto InlinedVector<T, N, A>::InsertWithRange(const_iterator position,
-                                             ForwardIter first,
-                                             ForwardIter last,
+                                             ForwardIterator first,
+                                             ForwardIterator last,
                                              std::forward_iterator_tag)
     -> iterator {
   assert(position >= begin() && position <= end());
-  if (first == last) {
-    return const_cast<iterator>(position);
-  }
-  using Length = typename std::iterator_traits<ForwardIter>::difference_type;
-  Length n = std::distance(first, last);
+  if (ABSL_PREDICT_FALSE(first == last)) return const_cast<iterator>(position);
+
+  auto n = std::distance(first, last);
   std::pair<iterator, iterator> it_pair = ShiftRight(position, n);
   size_type used_spots = it_pair.second - it_pair.first;
-  ForwardIter open_spot = std::next(first, used_spots);
+  ForwardIterator open_spot = std::next(first, used_spots);
   std::copy(first, open_spot, it_pair.first);
   UninitializedCopy(open_spot, last, it_pair.second);
   return it_pair.first;