[libcxx-commits] [libcxx] 84fc2c3 - [libc++] Make the naming of private member variables consistent and enforce it through readability-identifier-naming

Nikolas Klauser via libcxx-commits libcxx-commits at lists.llvm.org
Fri Sep 2 12:36:46 PDT 2022


Author: Nikolas Klauser
Date: 2022-09-02T21:36:36+02:00
New Revision: 84fc2c3cd62ab5be51d65f818854bb031b74c0f2

URL: https://github.com/llvm/llvm-project/commit/84fc2c3cd62ab5be51d65f818854bb031b74c0f2
DIFF: https://github.com/llvm/llvm-project/commit/84fc2c3cd62ab5be51d65f818854bb031b74c0f2.diff

LOG: [libc++] Make the naming of private member variables consistent and enforce it through readability-identifier-naming

Reviewed By: ldionne, #libc

Spies: aheejin, sstefan1, libcxx-commits

Differential Revision: https://reviews.llvm.org/D129386

Added: 
    

Modified: 
    libcxx/.clang-tidy
    libcxx/include/__algorithm/shuffle.h
    libcxx/include/__algorithm/uniform_random_bit_generator_adaptor.h
    libcxx/include/__chrono/day.h
    libcxx/include/__chrono/hh_mm_ss.h
    libcxx/include/__chrono/month.h
    libcxx/include/__chrono/month_weekday.h
    libcxx/include/__chrono/monthday.h
    libcxx/include/__chrono/weekday.h
    libcxx/include/__chrono/year.h
    libcxx/include/__chrono/year_month.h
    libcxx/include/__chrono/year_month_day.h
    libcxx/include/__chrono/year_month_weekday.h
    libcxx/include/__iterator/reverse_iterator.h
    libcxx/include/__iterator/wrap_iter.h
    libcxx/include/__locale
    libcxx/include/__memory/shared_ptr.h
    libcxx/include/__random/normal_distribution.h
    libcxx/include/__random/shuffle_order_engine.h
    libcxx/include/__support/win32/locale_win32.h
    libcxx/include/any
    libcxx/include/barrier
    libcxx/include/codecvt
    libcxx/include/exception
    libcxx/include/experimental/functional
    libcxx/include/experimental/iterator
    libcxx/include/latch
    libcxx/include/map
    libcxx/include/semaphore
    libcxx/include/shared_mutex
    libcxx/include/span
    libcxx/include/string_view
    libcxx/include/unordered_map
    libcxx/include/variant
    libcxx/src/locale.cpp
    libcxx/src/memory.cpp
    libcxx/src/shared_mutex.cpp

Removed: 
    


################################################################################
diff  --git a/libcxx/.clang-tidy b/libcxx/.clang-tidy
index c8798af378ca9..88b9de1f56a81 100644
--- a/libcxx/.clang-tidy
+++ b/libcxx/.clang-tidy
@@ -39,6 +39,12 @@ CheckOptions:
     value: lower_case
   - key:   readability-identifier-naming.ParameterPrefix
     value: __
+  - key:   readability-identifier-naming.PrivateMemberCase
+    value: lower_case
+  - key:   readability-identifier-naming.PrivateMemberPrefix
+    value: __
+  - key:   readability-identifier-naming.PrivateMemberSuffix
+    value: _
 
 # TODO: investigate these checks
 # bugprone-branch-clone,

diff  --git a/libcxx/include/__algorithm/shuffle.h b/libcxx/include/__algorithm/shuffle.h
index b5ce291e7a97a..c2f5c37efa8d1 100644
--- a/libcxx/include/__algorithm/shuffle.h
+++ b/libcxx/include/__algorithm/shuffle.h
@@ -31,9 +31,9 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 class _LIBCPP_TYPE_VIS __libcpp_debug_randomizer {
 public:
   __libcpp_debug_randomizer() {
-    __state = __seed();
-    __inc = __state + 0xda3e39cb94b95bdbULL;
-    __inc = (__inc << 1) | 1;
+    __state_ = __seed();
+    __inc_ = __state_ + 0xda3e39cb94b95bdbULL;
+    __inc_ = (__inc_ << 1) | 1;
   }
   typedef uint_fast32_t result_type;
 
@@ -41,8 +41,8 @@ class _LIBCPP_TYPE_VIS __libcpp_debug_randomizer {
   static const result_type _Max = 0xFFFFFFFF;
 
   _LIBCPP_HIDE_FROM_ABI result_type operator()() {
-    uint_fast64_t __oldstate = __state;
-    __state = __oldstate * 6364136223846793005ULL + __inc;
+    uint_fast64_t __oldstate = __state_;
+    __state_ = __oldstate * 6364136223846793005ULL + __inc_;
     return __oldstate >> 32;
   }
 
@@ -50,8 +50,8 @@ class _LIBCPP_TYPE_VIS __libcpp_debug_randomizer {
   static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type max() { return _Max; }
 
 private:
-  uint_fast64_t __state;
-  uint_fast64_t __inc;
+  uint_fast64_t __state_;
+  uint_fast64_t __inc_;
   _LIBCPP_HIDE_FROM_ABI static uint_fast64_t __seed() {
 #ifdef _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED
     return _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED;

diff  --git a/libcxx/include/__algorithm/uniform_random_bit_generator_adaptor.h b/libcxx/include/__algorithm/uniform_random_bit_generator_adaptor.h
index 04a67752dd0bc..7d0d3e196e18f 100644
--- a/libcxx/include/__algorithm/uniform_random_bit_generator_adaptor.h
+++ b/libcxx/include/__algorithm/uniform_random_bit_generator_adaptor.h
@@ -36,7 +36,7 @@ template <class _Gen>
 class _ClassicGenAdaptor {
 private:
   // The generator is not required to be copyable or movable, so it has to be stored as a reference.
-  _Gen& __gen;
+  _Gen& __gen_;
 
 public:
   using result_type = invoke_result_t<_Gen&>;
@@ -47,10 +47,10 @@ class _ClassicGenAdaptor {
   static constexpr auto max() { return __uncvref_t<_Gen>::max(); }
 
   _LIBCPP_HIDE_FROM_ABI
-  constexpr explicit _ClassicGenAdaptor(_Gen& __g) : __gen(__g) {}
+  constexpr explicit _ClassicGenAdaptor(_Gen& __g) : __gen_(__g) {}
 
   _LIBCPP_HIDE_FROM_ABI
-  constexpr auto operator()() const { return __gen(); }
+  constexpr auto operator()() const { return __gen_(); }
 };
 
 _LIBCPP_END_NAMESPACE_STD

diff  --git a/libcxx/include/__chrono/day.h b/libcxx/include/__chrono/day.h
index d9fa4ffbc45e9..35ecfcf9e5bd1 100644
--- a/libcxx/include/__chrono/day.h
+++ b/libcxx/include/__chrono/day.h
@@ -27,18 +27,18 @@ namespace chrono
 
 class day {
 private:
-    unsigned char __d;
+    unsigned char __d_;
 public:
     _LIBCPP_HIDE_FROM_ABI day() = default;
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr day(unsigned __val) noexcept : __d(static_cast<unsigned char>(__val)) {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr day& operator++()    noexcept { ++__d; return *this; }
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr day(unsigned __val) noexcept : __d_(static_cast<unsigned char>(__val)) {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr day& operator++()    noexcept { ++__d_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr day  operator++(int) noexcept { day __tmp = *this; ++(*this); return __tmp; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr day& operator--()    noexcept { --__d; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr day& operator--()    noexcept { --__d_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr day  operator--(int) noexcept { day __tmp = *this; --(*this); return __tmp; }
     _LIBCPP_HIDE_FROM_ABI        constexpr day& operator+=(const days& __dd) noexcept;
     _LIBCPP_HIDE_FROM_ABI        constexpr day& operator-=(const days& __dd) noexcept;
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator unsigned() const noexcept { return __d; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __d >= 1 && __d <= 31; }
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator unsigned() const noexcept { return __d_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __d_ >= 1 && __d_ <= 31; }
   };
 
 

diff  --git a/libcxx/include/__chrono/hh_mm_ss.h b/libcxx/include/__chrono/hh_mm_ss.h
index 6b3c5c09e68e1..fde005d097a12 100644
--- a/libcxx/include/__chrono/hh_mm_ss.h
+++ b/libcxx/include/__chrono/hh_mm_ss.h
@@ -57,33 +57,33 @@ class hh_mm_ss
     _LIBCPP_HIDE_FROM_ABI constexpr hh_mm_ss() noexcept : hh_mm_ss{_Duration::zero()} {}
 
     _LIBCPP_HIDE_FROM_ABI constexpr explicit hh_mm_ss(_Duration __d) noexcept :
-        __is_neg(__d < _Duration(0)),
-        __h(duration_cast<chrono::hours>  (abs(__d))),
-        __m(duration_cast<chrono::minutes>(abs(__d) - hours())),
-        __s(duration_cast<chrono::seconds>(abs(__d) - hours() - minutes())),
-        __f(duration_cast<precision>      (abs(__d) - hours() - minutes() - seconds()))
+        __is_neg_(__d < _Duration(0)),
+        __h_(duration_cast<chrono::hours>  (abs(__d))),
+        __m_(duration_cast<chrono::minutes>(abs(__d) - hours())),
+        __s_(duration_cast<chrono::seconds>(abs(__d) - hours() - minutes())),
+        __f_(duration_cast<precision>      (abs(__d) - hours() - minutes() - seconds()))
         {}
 
-    _LIBCPP_HIDE_FROM_ABI constexpr bool is_negative()        const noexcept { return __is_neg; }
-    _LIBCPP_HIDE_FROM_ABI constexpr chrono::hours hours()     const noexcept { return __h; }
-    _LIBCPP_HIDE_FROM_ABI constexpr chrono::minutes minutes() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI constexpr chrono::seconds seconds() const noexcept { return __s; }
-    _LIBCPP_HIDE_FROM_ABI constexpr precision subseconds()    const noexcept { return __f; }
+    _LIBCPP_HIDE_FROM_ABI constexpr bool is_negative()        const noexcept { return __is_neg_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr chrono::hours hours()     const noexcept { return __h_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr chrono::minutes minutes() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr chrono::seconds seconds() const noexcept { return __s_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr precision subseconds()    const noexcept { return __f_; }
 
     _LIBCPP_HIDE_FROM_ABI constexpr precision to_duration() const noexcept
     {
-        auto __dur = __h + __m + __s + __f;
-        return __is_neg ? -__dur : __dur;
+        auto __dur = __h_ + __m_ + __s_ + __f_;
+        return __is_neg_ ? -__dur : __dur;
     }
 
     _LIBCPP_HIDE_FROM_ABI constexpr explicit operator precision() const noexcept { return to_duration(); }
 
 private:
-    bool            __is_neg;
-    chrono::hours   __h;
-    chrono::minutes __m;
-    chrono::seconds __s;
-    precision       __f;
+    bool            __is_neg_;
+    chrono::hours   __h_;
+    chrono::minutes __m_;
+    chrono::seconds __s_;
+    precision       __f_;
 };
 
 _LIBCPP_HIDE_FROM_ABI constexpr bool is_am(const hours& __h) noexcept { return __h >= hours( 0) && __h < hours(12); }

diff  --git a/libcxx/include/__chrono/month.h b/libcxx/include/__chrono/month.h
index b3e2d69288266..e929f248842e5 100644
--- a/libcxx/include/__chrono/month.h
+++ b/libcxx/include/__chrono/month.h
@@ -27,18 +27,18 @@ namespace chrono
 
 class month {
 private:
-    unsigned char __m;
+    unsigned char __m_;
 public:
     _LIBCPP_HIDE_FROM_ABI month() = default;
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr month(unsigned __val) noexcept : __m(static_cast<unsigned char>(__val)) {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr month& operator++()    noexcept { ++__m; return *this; }
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr month(unsigned __val) noexcept : __m_(static_cast<unsigned char>(__val)) {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr month& operator++()    noexcept { ++__m_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr month  operator++(int) noexcept { month __tmp = *this; ++(*this); return __tmp; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr month& operator--()    noexcept { --__m; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr month& operator--()    noexcept { --__m_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr month  operator--(int) noexcept { month __tmp = *this; --(*this); return __tmp; }
     _LIBCPP_HIDE_FROM_ABI        constexpr month& operator+=(const months& __m1) noexcept;
     _LIBCPP_HIDE_FROM_ABI        constexpr month& operator-=(const months& __m1) noexcept;
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator unsigned() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __m >= 1 && __m <= 12; }
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator unsigned() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __m_ >= 1 && __m_ <= 12; }
 };
 
 

diff  --git a/libcxx/include/__chrono/month_weekday.h b/libcxx/include/__chrono/month_weekday.h
index 2700513970173..01cdf76d84bb0 100644
--- a/libcxx/include/__chrono/month_weekday.h
+++ b/libcxx/include/__chrono/month_weekday.h
@@ -27,14 +27,14 @@ namespace chrono
 
 class month_weekday {
 private:
-    chrono::month __m;
-    chrono::weekday_indexed __wdi;
+    chrono::month __m_;
+    chrono::weekday_indexed __wdi_;
 public:
     _LIBCPP_HIDE_FROM_ABI constexpr month_weekday(const chrono::month& __mval, const chrono::weekday_indexed& __wdival) noexcept
-        : __m{__mval}, __wdi{__wdival} {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                     month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool                                 ok() const noexcept { return __m.ok() && __wdi.ok(); }
+        : __m_{__mval}, __wdi_{__wdival} {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                     month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool                                 ok() const noexcept { return __m_.ok() && __wdi_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
@@ -63,14 +63,14 @@ month_weekday operator/(const weekday_indexed& __lhs, int __rhs) noexcept
 
 
 class month_weekday_last {
-    chrono::month        __m;
-    chrono::weekday_last __wdl;
+    chrono::month        __m_;
+    chrono::weekday_last __wdl_;
   public:
     _LIBCPP_HIDE_FROM_ABI constexpr month_weekday_last(const chrono::month& __mval, const chrono::weekday_last& __wdlval) noexcept
-        : __m{__mval}, __wdl{__wdlval} {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month               month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool                           ok() const noexcept { return __m.ok() && __wdl.ok(); }
+        : __m_{__mval}, __wdl_{__wdlval} {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month               month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool                           ok() const noexcept { return __m_.ok() && __wdl_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr

diff  --git a/libcxx/include/__chrono/monthday.h b/libcxx/include/__chrono/monthday.h
index dec1d6bfdbfb0..c0ee3e4a94fda 100644
--- a/libcxx/include/__chrono/monthday.h
+++ b/libcxx/include/__chrono/monthday.h
@@ -29,26 +29,26 @@ namespace chrono
 
 class month_day {
 private:
-   chrono::month __m;
-   chrono::day   __d;
+   chrono::month __m_;
+   chrono::day   __d_;
 public:
     _LIBCPP_HIDE_FROM_ABI month_day() = default;
     _LIBCPP_HIDE_FROM_ABI constexpr month_day(const chrono::month& __mval, const chrono::day& __dval) noexcept
-        : __m{__mval}, __d{__dval} {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::day   day()   const noexcept { return __d; }
+        : __m_{__mval}, __d_{__dval} {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::day   day()   const noexcept { return __d_; }
     _LIBCPP_HIDE_FROM_ABI constexpr bool ok() const noexcept;
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
 bool month_day::ok() const noexcept
 {
-    if (!__m.ok()) return false;
-    const unsigned __dval = static_cast<unsigned>(__d);
+    if (!__m_.ok()) return false;
+    const unsigned __dval = static_cast<unsigned>(__d_);
     if (__dval < 1 || __dval > 31) return false;
     if (__dval <= 29) return true;
 //  Now we've got either 30 or 31
-    const unsigned __mval = static_cast<unsigned>(__m);
+    const unsigned __mval = static_cast<unsigned>(__m_);
     if (__mval == 2) return false;
     if (__mval == 4 || __mval == 6 || __mval == 9 || __mval == 11)
         return __dval == 30;
@@ -87,12 +87,12 @@ month_day operator/(const day& __lhs, int __rhs) noexcept
 
 class month_day_last {
 private:
-    chrono::month __m;
+    chrono::month __m_;
 public:
     _LIBCPP_HIDE_FROM_ABI explicit constexpr month_day_last(const chrono::month& __val) noexcept
-        : __m{__val} {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __m.ok(); }
+        : __m_{__val} {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __m_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr

diff  --git a/libcxx/include/__chrono/weekday.h b/libcxx/include/__chrono/weekday.h
index bad6781110f1c..e0bc8a4cae2be 100644
--- a/libcxx/include/__chrono/weekday.h
+++ b/libcxx/include/__chrono/weekday.h
@@ -32,25 +32,25 @@ class weekday_last;
 
 class weekday {
 private:
-    unsigned char __wd;
+    unsigned char __wd_;
     _LIBCPP_HIDE_FROM_ABI static constexpr unsigned char __weekday_from_days(int __days) noexcept;
 public:
   _LIBCPP_HIDE_FROM_ABI weekday() = default;
-  _LIBCPP_HIDE_FROM_ABI inline explicit constexpr weekday(unsigned __val) noexcept : __wd(static_cast<unsigned char>(__val == 7 ? 0 : __val)) {}
+  _LIBCPP_HIDE_FROM_ABI inline explicit constexpr weekday(unsigned __val) noexcept : __wd_(static_cast<unsigned char>(__val == 7 ? 0 : __val)) {}
   _LIBCPP_HIDE_FROM_ABI inline constexpr          weekday(const sys_days& __sysd) noexcept
-          : __wd(__weekday_from_days(__sysd.time_since_epoch().count())) {}
+          : __wd_(__weekday_from_days(__sysd.time_since_epoch().count())) {}
   _LIBCPP_HIDE_FROM_ABI inline explicit constexpr weekday(const local_days& __locd) noexcept
-          : __wd(__weekday_from_days(__locd.time_since_epoch().count())) {}
+          : __wd_(__weekday_from_days(__locd.time_since_epoch().count())) {}
 
-  _LIBCPP_HIDE_FROM_ABI inline constexpr weekday& operator++()    noexcept { __wd = (__wd == 6 ? 0 : __wd + 1); return *this; }
+  _LIBCPP_HIDE_FROM_ABI inline constexpr weekday& operator++()    noexcept { __wd_ = (__wd_ == 6 ? 0 : __wd_ + 1); return *this; }
   _LIBCPP_HIDE_FROM_ABI inline constexpr weekday  operator++(int) noexcept { weekday __tmp = *this; ++(*this); return __tmp; }
-  _LIBCPP_HIDE_FROM_ABI inline constexpr weekday& operator--()    noexcept { __wd = (__wd == 0 ? 6 : __wd - 1); return *this; }
+  _LIBCPP_HIDE_FROM_ABI inline constexpr weekday& operator--()    noexcept { __wd_ = (__wd_ == 0 ? 6 : __wd_ - 1); return *this; }
   _LIBCPP_HIDE_FROM_ABI inline constexpr weekday  operator--(int) noexcept { weekday __tmp = *this; --(*this); return __tmp; }
   _LIBCPP_HIDE_FROM_ABI        constexpr weekday& operator+=(const days& __dd) noexcept;
   _LIBCPP_HIDE_FROM_ABI        constexpr weekday& operator-=(const days& __dd) noexcept;
-  _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned c_encoding()   const noexcept { return __wd; }
-  _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned iso_encoding() const noexcept { return __wd == 0u ? 7 : __wd; }
-  _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __wd <= 6; }
+  _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned c_encoding()   const noexcept { return __wd_; }
+  _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned iso_encoding() const noexcept { return __wd_ == 0u ? 7 : __wd_; }
+  _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __wd_ <= 6; }
   _LIBCPP_HIDE_FROM_ABI        constexpr weekday_indexed operator[](unsigned __index) const noexcept;
   _LIBCPP_HIDE_FROM_ABI        constexpr weekday_last    operator[](last_spec) const noexcept;
 };
@@ -123,15 +123,15 @@ weekday& weekday::operator-=(const days& __dd) noexcept
 
 class weekday_indexed {
 private:
-    chrono::weekday __wd;
-    unsigned char   __idx;
+    chrono::weekday __wd_;
+    unsigned char   __idx_;
 public:
     _LIBCPP_HIDE_FROM_ABI weekday_indexed() = default;
     _LIBCPP_HIDE_FROM_ABI inline constexpr weekday_indexed(const chrono::weekday& __wdval, unsigned __idxval) noexcept
-        : __wd{__wdval}, __idx(__idxval) {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday weekday() const noexcept { return __wd; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned                 index() const noexcept { return __idx; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __wd.ok() && __idx >= 1 && __idx <= 5; }
+        : __wd_{__wdval}, __idx_(__idxval) {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday weekday() const noexcept { return __wd_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned                 index() const noexcept { return __idx_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __wd_.ok() && __idx_ >= 1 && __idx_ <= 5; }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
@@ -145,12 +145,12 @@ bool operator!=(const weekday_indexed& __lhs, const weekday_indexed& __rhs) noex
 
 class weekday_last {
 private:
-    chrono::weekday __wd;
+    chrono::weekday __wd_;
 public:
     _LIBCPP_HIDE_FROM_ABI explicit constexpr weekday_last(const chrono::weekday& __val) noexcept
-        : __wd{__val} {}
-    _LIBCPP_HIDE_FROM_ABI constexpr chrono::weekday weekday() const noexcept { return __wd; }
-    _LIBCPP_HIDE_FROM_ABI constexpr bool ok() const noexcept { return __wd.ok(); }
+        : __wd_{__val} {}
+    _LIBCPP_HIDE_FROM_ABI constexpr chrono::weekday weekday() const noexcept { return __wd_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr bool ok() const noexcept { return __wd_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr

diff  --git a/libcxx/include/__chrono/year.h b/libcxx/include/__chrono/year.h
index 425c08ba49607..79ee8a02b8fb8 100644
--- a/libcxx/include/__chrono/year.h
+++ b/libcxx/include/__chrono/year.h
@@ -31,22 +31,22 @@ namespace chrono
 
 class year {
 private:
-    short __y;
+    short __y_;
 public:
     _LIBCPP_HIDE_FROM_ABI year() = default;
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr year(int __val) noexcept : __y(static_cast<short>(__val)) {}
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr year(int __val) noexcept : __y_(static_cast<short>(__val)) {}
 
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year& operator++()    noexcept { ++__y; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year& operator++()    noexcept { ++__y_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr year  operator++(int) noexcept { year __tmp = *this; ++(*this); return __tmp; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year& operator--()    noexcept { --__y; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year& operator--()    noexcept { --__y_; return *this; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr year  operator--(int) noexcept { year __tmp = *this; --(*this); return __tmp; }
     _LIBCPP_HIDE_FROM_ABI        constexpr year& operator+=(const years& __dy) noexcept;
     _LIBCPP_HIDE_FROM_ABI        constexpr year& operator-=(const years& __dy) noexcept;
     _LIBCPP_HIDE_FROM_ABI inline constexpr year operator+() const noexcept { return *this; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year operator-() const noexcept { return year{-__y}; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year operator-() const noexcept { return year{-__y_}; }
 
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool is_leap() const noexcept { return __y % 4 == 0 && (__y % 100 != 0 || __y % 400 == 0); }
-    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator int() const noexcept { return __y; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool is_leap() const noexcept { return __y_ % 4 == 0 && (__y_ % 100 != 0 || __y_ % 400 == 0); }
+    _LIBCPP_HIDE_FROM_ABI explicit inline constexpr operator int() const noexcept { return __y_; }
     _LIBCPP_HIDE_FROM_ABI        constexpr bool ok() const noexcept;
     _LIBCPP_HIDE_FROM_ABI static inline constexpr year min() noexcept { return year{-32767}; }
     _LIBCPP_HIDE_FROM_ABI static inline constexpr year max() noexcept { return year{ 32767}; }
@@ -87,8 +87,8 @@ year& year::operator-=(const years& __dy) noexcept
 { *this = *this - __dy; return *this; }
 
 _LIBCPP_HIDE_FROM_ABI constexpr bool year::ok() const noexcept {
-  static_assert(static_cast<int>(std::numeric_limits<decltype(__y)>::max()) == static_cast<int>(max()));
-  return static_cast<int>(min()) <= __y;
+  static_assert(static_cast<int>(std::numeric_limits<decltype(__y_)>::max()) == static_cast<int>(max()));
+  return static_cast<int>(min()) <= __y_;
 }
 
 } // namespace chrono

diff  --git a/libcxx/include/__chrono/year_month.h b/libcxx/include/__chrono/year_month.h
index 422d24fbf9867..9f1e65c8c83d9 100644
--- a/libcxx/include/__chrono/year_month.h
+++ b/libcxx/include/__chrono/year_month.h
@@ -28,19 +28,19 @@ namespace chrono
 {
 
 class year_month {
-    chrono::year  __y;
-    chrono::month __m;
+    chrono::year  __y_;
+    chrono::month __m_;
 public:
     _LIBCPP_HIDE_FROM_ABI year_month() = default;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month(const chrono::year& __yval, const chrono::month& __mval) noexcept
-        : __y{__yval}, __m{__mval} {}
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year  year()  const noexcept { return __y; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const months& __dm) noexcept { this->__m += __dm; return *this; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const months& __dm) noexcept { this->__m -= __dm; return *this; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const years& __dy)  noexcept { this->__y += __dy; return *this; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const years& __dy)  noexcept { this->__y -= __dy; return *this; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __y.ok() && __m.ok(); }
+        : __y_{__yval}, __m_{__mval} {}
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year  year()  const noexcept { return __y_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const months& __dm) noexcept { this->__m_ += __dm; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const months& __dm) noexcept { this->__m_ -= __dm; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const years& __dy)  noexcept { this->__y_ += __dy; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const years& __dy)  noexcept { this->__y_ -= __dy; return *this; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __y_.ok() && __m_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr

diff  --git a/libcxx/include/__chrono/year_month_day.h b/libcxx/include/__chrono/year_month_day.h
index 9c7b1a42f23b1..b74901470c66e 100644
--- a/libcxx/include/__chrono/year_month_day.h
+++ b/libcxx/include/__chrono/year_month_day.h
@@ -38,14 +38,14 @@ class year_month_day_last;
 
 class year_month_day {
 private:
-    chrono::year  __y;
-    chrono::month __m;
-    chrono::day   __d;
+    chrono::year  __y_;
+    chrono::month __m_;
+    chrono::day   __d_;
 public:
      _LIBCPP_HIDE_FROM_ABI year_month_day() = default;
      _LIBCPP_HIDE_FROM_ABI inline constexpr year_month_day(
             const chrono::year& __yval, const chrono::month& __mval, const chrono::day& __dval) noexcept
-            : __y{__yval}, __m{__mval}, __d{__dval} {}
+            : __y_{__yval}, __m_{__mval}, __d_{__dval} {}
      _LIBCPP_HIDE_FROM_ABI        constexpr year_month_day(const year_month_day_last& __ymdl) noexcept;
      _LIBCPP_HIDE_FROM_ABI inline constexpr year_month_day(const sys_days& __sysd) noexcept
             : year_month_day(__from_days(__sysd.time_since_epoch())) {}
@@ -57,9 +57,9 @@ class year_month_day {
      _LIBCPP_HIDE_FROM_ABI        constexpr year_month_day& operator+=(const years& __dy)  noexcept;
      _LIBCPP_HIDE_FROM_ABI        constexpr year_month_day& operator-=(const years& __dy)  noexcept;
 
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year   year() const noexcept { return __y; }
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m; }
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::day     day() const noexcept { return __d; }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year   year() const noexcept { return __y_; }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m_; }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::day     day() const noexcept { return __d_; }
      _LIBCPP_HIDE_FROM_ABI inline constexpr operator   sys_days() const noexcept          { return   sys_days{__to_days()}; }
      _LIBCPP_HIDE_FROM_ABI inline explicit constexpr operator local_days() const noexcept { return local_days{__to_days()}; }
 
@@ -95,9 +95,9 @@ days year_month_day::__to_days() const noexcept
     static_assert(numeric_limits<unsigned>::digits >= 18, "");
     static_assert(numeric_limits<int>::digits >= 20     , "");
 
-    const int      __yr  = static_cast<int>(__y) - (__m <= February);
-    const unsigned __mth = static_cast<unsigned>(__m);
-    const unsigned __dy  = static_cast<unsigned>(__d);
+    const int      __yr  = static_cast<int>(__y_) - (__m_ <= February);
+    const unsigned __mth = static_cast<unsigned>(__m_);
+    const unsigned __dy  = static_cast<unsigned>(__d_);
 
     const int      __era = (__yr >= 0 ? __yr : __yr - 399) / 400;
     const unsigned __yoe = static_cast<unsigned>(__yr - __era * 400);                // [0, 399]
@@ -175,24 +175,24 @@ _LIBCPP_HIDE_FROM_ABI inline constexpr year_month_day& year_month_day::operator-
 
 class year_month_day_last {
 private:
-    chrono::year           __y;
-    chrono::month_day_last __mdl;
+    chrono::year           __y_;
+    chrono::month_day_last __mdl_;
 public:
      _LIBCPP_HIDE_FROM_ABI constexpr year_month_day_last(const year& __yval, const month_day_last& __mdlval) noexcept
-        : __y{__yval}, __mdl{__mdlval} {}
+        : __y_{__yval}, __mdl_{__mdlval} {}
 
      _LIBCPP_HIDE_FROM_ABI constexpr year_month_day_last& operator+=(const months& __m) noexcept;
      _LIBCPP_HIDE_FROM_ABI constexpr year_month_day_last& operator-=(const months& __m) noexcept;
      _LIBCPP_HIDE_FROM_ABI constexpr year_month_day_last& operator+=(const years& __y)  noexcept;
      _LIBCPP_HIDE_FROM_ABI constexpr year_month_day_last& operator-=(const years& __y)  noexcept;
 
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                     year() const noexcept { return __y; }
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                   month() const noexcept { return __mdl.month(); }
-     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month_day_last month_day_last() const noexcept { return __mdl; }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                     year() const noexcept { return __y_; }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                   month() const noexcept { return __mdl_.month(); }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month_day_last month_day_last() const noexcept { return __mdl_; }
      _LIBCPP_HIDE_FROM_ABI        constexpr chrono::day                       day() const noexcept;
      _LIBCPP_HIDE_FROM_ABI inline constexpr operator                     sys_days() const noexcept { return   sys_days{year()/month()/day()}; }
      _LIBCPP_HIDE_FROM_ABI inline explicit constexpr operator          local_days() const noexcept { return local_days{year()/month()/day()}; }
-     _LIBCPP_HIDE_FROM_ABI inline constexpr bool                               ok() const noexcept { return __y.ok() && __mdl.ok(); }
+     _LIBCPP_HIDE_FROM_ABI inline constexpr bool                               ok() const noexcept { return __y_.ok() && __mdl_.ok(); }
 };
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
@@ -205,7 +205,7 @@ chrono::day year_month_day_last::day() const noexcept
         chrono::day(31), chrono::day(31), chrono::day(30),
         chrono::day(31), chrono::day(30), chrono::day(31)
     };
-    return (month() != February || !__y.is_leap()) && month().ok() ?
+    return (month() != February || !__y_.is_leap()) && month().ok() ?
         __d[static_cast<unsigned>(month()) - 1] : chrono::day{29};
 }
 
@@ -289,13 +289,13 @@ _LIBCPP_HIDE_FROM_ABI inline constexpr year_month_day_last& year_month_day_last:
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
 year_month_day::year_month_day(const year_month_day_last& __ymdl) noexcept
-    : __y{__ymdl.year()}, __m{__ymdl.month()}, __d{__ymdl.day()} {}
+    : __y_{__ymdl.year()}, __m_{__ymdl.month()}, __d_{__ymdl.day()} {}
 
 _LIBCPP_HIDE_FROM_ABI inline constexpr
 bool year_month_day::ok() const noexcept
 {
-    if (!__y.ok() || !__m.ok()) return false;
-    return chrono::day{1} <= __d && __d <= (__y / __m / last).day();
+    if (!__y_.ok() || !__m_.ok()) return false;
+    return chrono::day{1} <= __d_ && __d_ <= (__y_ / __m_ / last).day();
 }
 
 } // namespace chrono

diff  --git a/libcxx/include/__chrono/year_month_weekday.h b/libcxx/include/__chrono/year_month_weekday.h
index b69b77152fb1c..6604deaf12cdc 100644
--- a/libcxx/include/__chrono/year_month_weekday.h
+++ b/libcxx/include/__chrono/year_month_weekday.h
@@ -35,14 +35,14 @@ namespace chrono
 {
 
 class year_month_weekday {
-    chrono::year            __y;
-    chrono::month           __m;
-    chrono::weekday_indexed __wdi;
+    chrono::year            __y_;
+    chrono::month           __m_;
+    chrono::weekday_indexed __wdi_;
 public:
     _LIBCPP_HIDE_FROM_ABI year_month_weekday() = default;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday(const chrono::year& __yval, const chrono::month& __mval,
                                const chrono::weekday_indexed& __wdival) noexcept
-        : __y{__yval}, __m{__mval}, __wdi{__wdival} {}
+        : __y_{__yval}, __m_{__mval}, __wdi_{__wdival} {}
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday(const sys_days& __sysd) noexcept
             : year_month_weekday(__from_days(__sysd.time_since_epoch())) {}
     _LIBCPP_HIDE_FROM_ABI inline explicit constexpr year_month_weekday(const local_days& __locd) noexcept
@@ -52,24 +52,24 @@ class year_month_weekday {
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday& operator+=(const years&)  noexcept;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday& operator-=(const years&)  noexcept;
 
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                       year() const noexcept { return __y; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                     month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday                 weekday() const noexcept { return __wdi.weekday(); }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned                          index() const noexcept { return __wdi.index(); }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                       year() const noexcept { return __y_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month                     month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday                 weekday() const noexcept { return __wdi_.weekday(); }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr unsigned                          index() const noexcept { return __wdi_.index(); }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi_; }
 
     _LIBCPP_HIDE_FROM_ABI inline constexpr                       operator sys_days() const noexcept { return   sys_days{__to_days()}; }
     _LIBCPP_HIDE_FROM_ABI inline explicit constexpr operator            local_days() const noexcept { return local_days{__to_days()}; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept
     {
-        if (!__y.ok() || !__m.ok() || !__wdi.ok()) return false;
-        if (__wdi.index() <= 4) return true;
+        if (!__y_.ok() || !__m_.ok() || !__wdi_.ok()) return false;
+        if (__wdi_.index() <= 4) return true;
         auto __nth_weekday_day =
-            __wdi.weekday() -
-            chrono::weekday{static_cast<sys_days>(__y / __m / 1)} +
-            days{(__wdi.index() - 1) * 7 + 1};
+            __wdi_.weekday() -
+            chrono::weekday{static_cast<sys_days>(__y_ / __m_ / 1)} +
+            days{(__wdi_.index() - 1) * 7 + 1};
         return static_cast<unsigned>(__nth_weekday_day.count()) <=
-               static_cast<unsigned>((__y / __m / last).day());
+               static_cast<unsigned>((__y_ / __m_ / last).day());
     }
 
     _LIBCPP_HIDE_FROM_ABI static constexpr year_month_weekday __from_days(days __d) noexcept;
@@ -89,8 +89,8 @@ year_month_weekday year_month_weekday::__from_days(days __d) noexcept
 _LIBCPP_HIDE_FROM_ABI inline constexpr
 days year_month_weekday::__to_days() const noexcept
 {
-    const sys_days __sysd = sys_days(__y/__m/1);
-    return (__sysd + (__wdi.weekday() - chrono::weekday(__sysd) + days{(__wdi.index()-1)*7}))
+    const sys_days __sysd = sys_days(__y_/__m_/1);
+    return (__sysd + (__wdi_.weekday() - chrono::weekday(__sysd) + days{(__wdi_.index()-1)*7}))
                 .time_since_epoch();
 }
 
@@ -155,25 +155,25 @@ _LIBCPP_HIDE_FROM_ABI inline constexpr year_month_weekday& year_month_weekday::o
 
 class year_month_weekday_last {
 private:
-    chrono::year         __y;
-    chrono::month        __m;
-    chrono::weekday_last __wdl;
+    chrono::year         __y_;
+    chrono::month        __m_;
+    chrono::weekday_last __wdl_;
 public:
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday_last(const chrono::year& __yval, const chrono::month& __mval,
                                       const chrono::weekday_last& __wdlval) noexcept
-                : __y{__yval}, __m{__mval}, __wdl{__wdlval} {}
+                : __y_{__yval}, __m_{__mval}, __wdl_{__wdlval} {}
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday_last& operator+=(const months& __dm) noexcept;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday_last& operator-=(const months& __dm) noexcept;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday_last& operator+=(const years& __dy)  noexcept;
     _LIBCPP_HIDE_FROM_ABI constexpr year_month_weekday_last& operator-=(const years& __dy)  noexcept;
 
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                 year() const noexcept { return __y; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month               month() const noexcept { return __m; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday           weekday() const noexcept { return __wdl.weekday(); }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year                 year() const noexcept { return __y_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month               month() const noexcept { return __m_; }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday           weekday() const noexcept { return __wdl_.weekday(); }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl_; }
     _LIBCPP_HIDE_FROM_ABI inline constexpr operator                 sys_days() const noexcept { return   sys_days{__to_days()}; }
     _LIBCPP_HIDE_FROM_ABI inline explicit constexpr operator      local_days() const noexcept { return local_days{__to_days()}; }
-    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __y.ok() && __m.ok() && __wdl.ok(); }
+    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __y_.ok() && __m_.ok() && __wdl_.ok(); }
 
     _LIBCPP_HIDE_FROM_ABI constexpr days __to_days() const noexcept;
 
@@ -182,8 +182,8 @@ class year_month_weekday_last {
 _LIBCPP_HIDE_FROM_ABI inline constexpr
 days year_month_weekday_last::__to_days() const noexcept
 {
-    const sys_days __last = sys_days{__y/__m/last};
-    return (__last - (chrono::weekday{__last} - __wdl.weekday())).time_since_epoch();
+    const sys_days __last = sys_days{__y_/__m_/last};
+    return (__last - (chrono::weekday{__last} - __wdl_.weekday())).time_since_epoch();
 
 }
 

diff  --git a/libcxx/include/__iterator/reverse_iterator.h b/libcxx/include/__iterator/reverse_iterator.h
index 73f58053bbb66..2933a29fc8417 100644
--- a/libcxx/include/__iterator/reverse_iterator.h
+++ b/libcxx/include/__iterator/reverse_iterator.h
@@ -52,7 +52,7 @@ class _LIBCPP_TEMPLATE_VIS reverse_iterator
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 private:
 #ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
-    _Iter __t; // no longer used as of LWG #2360, not removed due to ABI break
+    _Iter __t_; // no longer used as of LWG #2360, not removed due to ABI break
 #endif
 
 #if _LIBCPP_STD_VER > 17
@@ -82,17 +82,17 @@ _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 #ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-    reverse_iterator() : __t(), current() {}
+    reverse_iterator() : __t_(), current() {}
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-    explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
+    explicit reverse_iterator(_Iter __x) : __t_(__x), current(__x) {}
 
     template <class _Up, class = __enable_if_t<
         !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
     > >
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
     reverse_iterator(const reverse_iterator<_Up>& __u)
-        : __t(__u.base()), current(__u.base())
+        : __t_(__u.base()), current(__u.base())
     { }
 
     template <class _Up, class = __enable_if_t<
@@ -102,7 +102,7 @@ _LIBCPP_SUPPRESS_DEPRECATED_POP
     > >
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
     reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
-        __t = current = __u.base();
+        __t_ = current = __u.base();
         return *this;
     }
 #else

diff  --git a/libcxx/include/__iterator/wrap_iter.h b/libcxx/include/__iterator/wrap_iter.h
index ea4447b263085..80be74ef58f81 100644
--- a/libcxx/include/__iterator/wrap_iter.h
+++ b/libcxx/include/__iterator/wrap_iter.h
@@ -38,17 +38,17 @@ class __wrap_iter
 #endif
 
 private:
-    iterator_type __i;
+    iterator_type __i_;
 public:
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter() _NOEXCEPT
-                : __i()
+                : __i_()
     {
         _VSTD::__debug_db_insert_i(this);
     }
     template <class _Up> _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
         __wrap_iter(const __wrap_iter<_Up>& __u,
             typename enable_if<is_convertible<_Up, iterator_type>::value>::type* = nullptr) _NOEXCEPT
-            : __i(__u.base())
+            : __i_(__u.base())
     {
 #ifdef _LIBCPP_ENABLE_DEBUG_MODE
       if (!__libcpp_is_constant_evaluated())
@@ -58,7 +58,7 @@ class __wrap_iter
 #ifdef _LIBCPP_ENABLE_DEBUG_MODE
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
     __wrap_iter(const __wrap_iter& __x)
-        : __i(__x.base())
+        : __i_(__x.base())
     {
       if (!__libcpp_is_constant_evaluated())
         __get_db()->__iterator_copy(this, _VSTD::addressof(__x));
@@ -70,7 +70,7 @@ class __wrap_iter
         {
             if (!__libcpp_is_constant_evaluated())
                 __get_db()->__iterator_copy(this, _VSTD::addressof(__x));
-            __i = __x.__i;
+            __i_ = __x.__i_;
         }
         return *this;
     }
@@ -85,19 +85,19 @@ class __wrap_iter
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
                              "Attempted to dereference a non-dereferenceable iterator");
-        return *__i;
+        return *__i_;
     }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pointer operator->() const _NOEXCEPT
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
                              "Attempted to dereference a non-dereferenceable iterator");
-        return _VSTD::__to_address(__i);
+        return _VSTD::__to_address(__i_);
     }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter& operator++() _NOEXCEPT
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
                              "Attempted to increment a non-incrementable iterator");
-        ++__i;
+        ++__i_;
         return *this;
     }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter  operator++(int) _NOEXCEPT
@@ -107,7 +107,7 @@ class __wrap_iter
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__decrementable(this),
                              "Attempted to decrement a non-decrementable iterator");
-        --__i;
+        --__i_;
         return *this;
     }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter  operator--(int) _NOEXCEPT
@@ -118,7 +118,7 @@ class __wrap_iter
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__addable(this, __n),
                              "Attempted to add/subtract an iterator outside its valid range");
-        __i += __n;
+        __i_ += __n;
         return *this;
     }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __wrap_iter  operator- (
diff erence_type __n) const _NOEXCEPT
@@ -129,14 +129,14 @@ class __wrap_iter
     {
         _LIBCPP_DEBUG_ASSERT(__get_const_db()->__subscriptable(this, __n),
                              "Attempted to subscript an iterator outside its valid range");
-        return __i[__n];
+        return __i_[__n];
     }
 
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 iterator_type base() const _NOEXCEPT {return __i;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 iterator_type base() const _NOEXCEPT {return __i_;}
 
 private:
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-    explicit __wrap_iter(const void* __p, iterator_type __x) _NOEXCEPT : __i(__x)
+    explicit __wrap_iter(const void* __p, iterator_type __x) _NOEXCEPT : __i_(__x)
     {
         (void)__p;
 #ifdef _LIBCPP_ENABLE_DEBUG_MODE

diff  --git a/libcxx/include/__locale b/libcxx/include/__locale
index 1588a223001fa..0bf8344ab5e19 100644
--- a/libcxx/include/__locale
+++ b/libcxx/include/__locale
@@ -350,7 +350,7 @@ template <>
 class _LIBCPP_TYPE_VIS collate_byname<char>
     : public collate<char>
 {
-    locale_t __l;
+    locale_t __l_;
 public:
     typedef char char_type;
     typedef basic_string<char_type> string_type;
@@ -370,7 +370,7 @@ template <>
 class _LIBCPP_TYPE_VIS collate_byname<wchar_t>
     : public collate<wchar_t>
 {
-    locale_t __l;
+    locale_t __l_;
 public:
     typedef wchar_t char_type;
     typedef basic_string<char_type> string_type;
@@ -792,7 +792,7 @@ template <>
 class _LIBCPP_TYPE_VIS ctype_byname<char>
     : public ctype<char>
 {
-    locale_t __l;
+    locale_t __l_;
 
 public:
     explicit ctype_byname(const char*, size_t = 0);
@@ -811,7 +811,7 @@ template <>
 class _LIBCPP_TYPE_VIS ctype_byname<wchar_t>
     : public ctype<wchar_t>
 {
-    locale_t __l;
+    locale_t __l_;
 
 public:
     explicit ctype_byname(const char*, size_t = 0);
@@ -1045,7 +1045,7 @@ class _LIBCPP_TYPE_VIS codecvt<wchar_t, char, mbstate_t>
     : public locale::facet,
       public codecvt_base
 {
-    locale_t __l;
+    locale_t __l_;
 public:
     typedef wchar_t   intern_type;
     typedef char      extern_type;

diff  --git a/libcxx/include/__memory/shared_ptr.h b/libcxx/include/__memory/shared_ptr.h
index 9239f9c629c9b..53113c0d61fd9 100644
--- a/libcxx/include/__memory/shared_ptr.h
+++ b/libcxx/include/__memory/shared_ptr.h
@@ -1799,7 +1799,7 @@ operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p);
 
 class _LIBCPP_TYPE_VIS __sp_mut
 {
-    void* __lx;
+    void* __lx_;
 public:
     void lock() _NOEXCEPT;
     void unlock() _NOEXCEPT;

diff  --git a/libcxx/include/__random/normal_distribution.h b/libcxx/include/__random/normal_distribution.h
index 3df62d65d1c21..b2ed47e6af460 100644
--- a/libcxx/include/__random/normal_distribution.h
+++ b/libcxx/include/__random/normal_distribution.h
@@ -58,8 +58,8 @@ class _LIBCPP_TEMPLATE_VIS normal_distribution
 
 private:
     param_type __p_;
-    result_type _V_;
-    bool _V_hot_;
+    result_type __v_;
+    bool __v_hot_;
 
 public:
     // constructors and reset functions
@@ -68,18 +68,18 @@ class _LIBCPP_TEMPLATE_VIS normal_distribution
     normal_distribution() : normal_distribution(0) {}
     _LIBCPP_INLINE_VISIBILITY
     explicit normal_distribution(result_type __mean, result_type __stddev = 1)
-        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
+        : __p_(param_type(__mean, __stddev)), __v_hot_(false) {}
 #else
     _LIBCPP_INLINE_VISIBILITY
     explicit normal_distribution(result_type __mean = 0,
                                  result_type __stddev = 1)
-        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
+        : __p_(param_type(__mean, __stddev)), __v_hot_(false) {}
 #endif
     _LIBCPP_INLINE_VISIBILITY
     explicit normal_distribution(const param_type& __p)
-        : __p_(__p), _V_hot_(false) {}
+        : __p_(__p), __v_hot_(false) {}
     _LIBCPP_INLINE_VISIBILITY
-    void reset() {_V_hot_ = false;}
+    void reset() {__v_hot_ = false;}
 
     // generating functions
     template<class _URNG>
@@ -107,8 +107,8 @@ class _LIBCPP_TEMPLATE_VIS normal_distribution
     friend _LIBCPP_INLINE_VISIBILITY
         bool operator==(const normal_distribution& __x,
                         const normal_distribution& __y)
-        {return __x.__p_ == __y.__p_ && __x._V_hot_ == __y._V_hot_ &&
-                (!__x._V_hot_ || __x._V_ == __y._V_);}
+        {return __x.__p_ == __y.__p_ && __x.__v_hot_ == __y.__v_hot_ &&
+                (!__x.__v_hot_ || __x.__v_ == __y.__v_);}
     friend _LIBCPP_INLINE_VISIBILITY
         bool operator!=(const normal_distribution& __x,
                         const normal_distribution& __y)
@@ -134,10 +134,10 @@ normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
 {
     static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
     result_type _Up;
-    if (_V_hot_)
+    if (__v_hot_)
     {
-        _V_hot_ = false;
-        _Up = _V_;
+        __v_hot_ = false;
+        _Up = __v_;
     }
     else
     {
@@ -152,8 +152,8 @@ normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
             __s = __u * __u + __v * __v;
         } while (__s > 1 || __s == 0);
         result_type _Fp = _VSTD::sqrt(-2 * _VSTD::log(__s) / __s);
-        _V_ = __v * _Fp;
-        _V_hot_ = true;
+        __v_ = __v * _Fp;
+        __v_hot_ = true;
         _Up = __u * _Fp;
     }
     return _Up * __p.stddev() + __p.mean();
@@ -170,9 +170,9 @@ operator<<(basic_ostream<_CharT, _Traits>& __os,
                _OStream::scientific);
     _CharT __sp = __os.widen(' ');
     __os.fill(__sp);
-    __os << __x.mean() << __sp << __x.stddev() << __sp << __x._V_hot_;
-    if (__x._V_hot_)
-        __os << __sp << __x._V_;
+    __os << __x.mean() << __sp << __x.stddev() << __sp << __x.__v_hot_;
+    if (__x.__v_hot_)
+        __os << __sp << __x.__v_;
     return __os;
 }
 
@@ -197,8 +197,8 @@ operator>>(basic_istream<_CharT, _Traits>& __is,
     if (!__is.fail())
     {
         __x.param(param_type(__mean, __stddev));
-        __x._V_hot_ = _V_hot;
-        __x._V_ = _Vp;
+        __x.__v_hot_ = _V_hot;
+        __x.__v_ = _Vp;
     }
     return __is;
 }

diff  --git a/libcxx/include/__random/shuffle_order_engine.h b/libcxx/include/__random/shuffle_order_engine.h
index fc7a4721520ca..4a27289c2f818 100644
--- a/libcxx/include/__random/shuffle_order_engine.h
+++ b/libcxx/include/__random/shuffle_order_engine.h
@@ -60,8 +60,8 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
 
 private:
     _Engine __e_;
-    result_type _V_[__k];
-    result_type _Y_;
+    result_type __v_[__k];
+    result_type __y_;
 
 public:
     // engine characteristics
@@ -157,8 +157,8 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
     void __init()
     {
         for (size_t __i = 0; __i < __k; ++__i)
-            _V_[__i] = __e_();
-        _Y_ = __e_();
+            __v_[__i] = __e_();
+        __y_ = __e_();
     }
 
     _LIBCPP_INLINE_VISIBILITY
@@ -190,11 +190,11 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
         >::type
         __eval(__uratio<_Np, _Dp>)
         {
-            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
+            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (__y_ - _Min)
                                                    / __uratio<_Np, _Dp>::den);
-            _Y_ = _V_[__j];
-            _V_[__j] = __e_();
-            return _Y_;
+            __y_ = __v_[__j];
+            __v_[__j] = __e_();
+            return __y_;
         }
 
     template <uint64_t __n, uint64_t __d>
@@ -204,10 +204,10 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
             const double _Fp = __d == 0 ?
                 __n / (2. * 0x8000000000000000ull) :
                 __n / (double)__d;
-            const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
-            _Y_ = _V_[__j];
-            _V_[__j] = __e_();
-            return _Y_;
+            const size_t __j = static_cast<size_t>(_Fp * (__y_ - _Min));
+            __y_ = __v_[__j];
+            __v_[__j] = __e_();
+            return __y_;
         }
 };
 
@@ -220,7 +220,7 @@ operator==(
     const shuffle_order_engine<_Eng, _Kp>& __x,
     const shuffle_order_engine<_Eng, _Kp>& __y)
 {
-    return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
+    return __x.__y_ == __y.__y_ && _VSTD::equal(__x.__v_, __x.__v_ + _Kp, __y.__v_) &&
            __x.__e_ == __y.__e_;
 }
 
@@ -245,10 +245,10 @@ operator<<(basic_ostream<_CharT, _Traits>& __os,
     __os.flags(_Ostream::dec | _Ostream::left);
     _CharT __sp = __os.widen(' ');
     __os.fill(__sp);
-    __os << __x.__e_ << __sp << __x._V_[0];
+    __os << __x.__e_ << __sp << __x.__v_[0];
     for (size_t __i = 1; __i < _Kp; ++__i)
-        __os << __sp << __x._V_[__i];
-    return __os << __sp << __x._Y_;
+        __os << __sp << __x.__v_[__i];
+    return __os << __sp << __x.__y_;
 }
 
 template <class _CharT, class _Traits,
@@ -270,8 +270,8 @@ operator>>(basic_istream<_CharT, _Traits>& __is,
     {
         __x.__e_ = __e;
         for (size_t __i = 0; __i < _Kp; ++__i)
-            __x._V_[__i] = _Vp[__i];
-        __x._Y_ = _Vp[_Kp];
+            __x.__v_[__i] = _Vp[__i];
+        __x.__y_ = _Vp[_Kp];
     }
     return __is;
 }

diff  --git a/libcxx/include/__support/win32/locale_win32.h b/libcxx/include/__support/win32/locale_win32.h
index 8127f286b6f38..6ee885408f0d8 100644
--- a/libcxx/include/__support/win32/locale_win32.h
+++ b/libcxx/include/__support/win32/locale_win32.h
@@ -14,6 +14,7 @@
 #include <cstddef>
 #include <locale.h> // _locale_t
 #include <stdio.h>
+#include <string>
 
 #define _X_ALL LC_ALL
 #define _X_COLLATE LC_COLLATE
@@ -50,92 +51,92 @@
 class __lconv_storage {
 public:
     __lconv_storage(const lconv *__lc_input) {
-        __lc = *__lc_input;
-
-        __decimal_point = __lc_input->decimal_point;
-        __thousands_sep = __lc_input->thousands_sep;
-        __grouping = __lc_input->grouping;
-        __int_curr_symbol = __lc_input->int_curr_symbol;
-        __currency_symbol = __lc_input->currency_symbol;
-        __mon_decimal_point = __lc_input->mon_decimal_point;
-        __mon_thousands_sep = __lc_input->mon_thousands_sep;
-        __mon_grouping = __lc_input->mon_grouping;
-        __positive_sign = __lc_input->positive_sign;
-        __negative_sign = __lc_input->negative_sign;
-
-        __lc.decimal_point = const_cast<char *>(__decimal_point.c_str());
-        __lc.thousands_sep = const_cast<char *>(__thousands_sep.c_str());
-        __lc.grouping = const_cast<char *>(__grouping.c_str());
-        __lc.int_curr_symbol = const_cast<char *>(__int_curr_symbol.c_str());
-        __lc.currency_symbol = const_cast<char *>(__currency_symbol.c_str());
-        __lc.mon_decimal_point = const_cast<char *>(__mon_decimal_point.c_str());
-        __lc.mon_thousands_sep = const_cast<char *>(__mon_thousands_sep.c_str());
-        __lc.mon_grouping = const_cast<char *>(__mon_grouping.c_str());
-        __lc.positive_sign = const_cast<char *>(__positive_sign.c_str());
-        __lc.negative_sign = const_cast<char *>(__negative_sign.c_str());
+        __lc_ = *__lc_input;
+
+        __decimal_point_ = __lc_input->decimal_point;
+        __thousands_sep_ = __lc_input->thousands_sep;
+        __grouping_ = __lc_input->grouping;
+        __int_curr_symbol_ = __lc_input->int_curr_symbol;
+        __currency_symbol_ = __lc_input->currency_symbol;
+        __mon_decimal_point_ = __lc_input->mon_decimal_point;
+        __mon_thousands_sep_ = __lc_input->mon_thousands_sep;
+        __mon_grouping_ = __lc_input->mon_grouping;
+        __positive_sign_ = __lc_input->positive_sign;
+        __negative_sign_ = __lc_input->negative_sign;
+
+        __lc_.decimal_point = const_cast<char *>(__decimal_point_.c_str());
+        __lc_.thousands_sep = const_cast<char *>(__thousands_sep_.c_str());
+        __lc_.grouping = const_cast<char *>(__grouping_.c_str());
+        __lc_.int_curr_symbol = const_cast<char *>(__int_curr_symbol_.c_str());
+        __lc_.currency_symbol = const_cast<char *>(__currency_symbol_.c_str());
+        __lc_.mon_decimal_point = const_cast<char *>(__mon_decimal_point_.c_str());
+        __lc_.mon_thousands_sep = const_cast<char *>(__mon_thousands_sep_.c_str());
+        __lc_.mon_grouping = const_cast<char *>(__mon_grouping_.c_str());
+        __lc_.positive_sign = const_cast<char *>(__positive_sign_.c_str());
+        __lc_.negative_sign = const_cast<char *>(__negative_sign_.c_str());
     }
 
     lconv *__get() {
-        return &__lc;
+        return &__lc_;
     }
 private:
-    lconv __lc;
-    std::string __decimal_point;
-    std::string __thousands_sep;
-    std::string __grouping;
-    std::string __int_curr_symbol;
-    std::string __currency_symbol;
-    std::string __mon_decimal_point;
-    std::string __mon_thousands_sep;
-    std::string __mon_grouping;
-    std::string __positive_sign;
-    std::string __negative_sign;
+    lconv __lc_;
+    std::string __decimal_point_;
+    std::string __thousands_sep_;
+    std::string __grouping_;
+    std::string __int_curr_symbol_;
+    std::string __currency_symbol_;
+    std::string __mon_decimal_point_;
+    std::string __mon_thousands_sep_;
+    std::string __mon_grouping_;
+    std::string __positive_sign_;
+    std::string __negative_sign_;
 };
 
 class locale_t {
 public:
     locale_t()
-        : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
+        : __locale_(nullptr), __locale_str_(nullptr), __lc_(nullptr) {}
     locale_t(std::nullptr_t)
-        : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
+        : __locale_(nullptr), __locale_str_(nullptr), __lc_(nullptr) {}
     locale_t(_locale_t __xlocale, const char* __xlocale_str)
-        : __locale(__xlocale), __locale_str(__xlocale_str), __lc(nullptr) {}
+        : __locale_(__xlocale), __locale_str_(__xlocale_str), __lc_(nullptr) {}
     locale_t(const locale_t &__l)
-        : __locale(__l.__locale), __locale_str(__l.__locale_str), __lc(nullptr) {}
+        : __locale_(__l.__locale_), __locale_str_(__l.__locale_str_), __lc_(nullptr) {}
 
     ~locale_t() {
-        delete __lc;
+        delete __lc_;
     }
 
     locale_t &operator =(const locale_t &__l) {
-        __locale = __l.__locale;
-        __locale_str = __l.__locale_str;
-        // __lc not copied
+        __locale_ = __l.__locale_;
+        __locale_str_ = __l.__locale_str_;
+        // __lc_ not copied
         return *this;
     }
 
     friend bool operator==(const locale_t& __left, const locale_t& __right) {
-        return __left.__locale == __right.__locale;
+        return __left.__locale_ == __right.__locale_;
     }
 
     friend bool operator==(const locale_t& __left, int __right) {
-        return __left.__locale == nullptr && __right == 0;
+        return __left.__locale_ == nullptr && __right == 0;
     }
 
     friend bool operator==(const locale_t& __left, long long __right) {
-        return __left.__locale == nullptr && __right == 0;
+        return __left.__locale_ == nullptr && __right == 0;
     }
 
     friend bool operator==(const locale_t& __left, std::nullptr_t) {
-        return __left.__locale == nullptr;
+        return __left.__locale_ == nullptr;
     }
 
     friend bool operator==(int __left, const locale_t& __right) {
-        return __left == 0 && nullptr == __right.__locale;
+        return __left == 0 && nullptr == __right.__locale_;
     }
 
     friend bool operator==(std::nullptr_t, const locale_t& __right) {
-        return nullptr == __right.__locale;
+        return nullptr == __right.__locale_;
     }
 
     friend bool operator!=(const locale_t& __left, const locale_t& __right) {
@@ -163,24 +164,24 @@ class locale_t {
     }
 
     operator bool() const {
-        return __locale != nullptr;
+        return __locale_ != nullptr;
     }
 
-    const char* __get_locale() const { return __locale_str; }
+    const char* __get_locale() const { return __locale_str_; }
 
     operator _locale_t() const {
-        return __locale;
+        return __locale_;
     }
 
     lconv *__store_lconv(const lconv *__input_lc) {
-        delete __lc;
-        __lc = new __lconv_storage(__input_lc);
-        return __lc->__get();
+        delete __lc_;
+        __lc_ = new __lconv_storage(__input_lc);
+        return __lc_->__get();
     }
 private:
-    _locale_t __locale;
-    const char* __locale_str;
-    __lconv_storage *__lc = nullptr;
+    _locale_t __locale_;
+    const char* __locale_str_;
+    __lconv_storage *__lc_ = nullptr;
 };
 
 // Locale management functions

diff  --git a/libcxx/include/any b/libcxx/include/any
index cd704a9543a5b..a70c6f11f37e3 100644
--- a/libcxx/include/any
+++ b/libcxx/include/any
@@ -194,18 +194,18 @@ class _LIBCPP_TEMPLATE_VIS any
 public:
   // construct/destruct
   _LIBCPP_INLINE_VISIBILITY
-  constexpr any() _NOEXCEPT : __h(nullptr) {}
+  constexpr any() _NOEXCEPT : __h_(nullptr) {}
 
   _LIBCPP_INLINE_VISIBILITY
-  any(any const & __other) : __h(nullptr)
+  any(any const & __other) : __h_(nullptr)
   {
-    if (__other.__h) __other.__call(_Action::_Copy, this);
+    if (__other.__h_) __other.__call(_Action::_Copy, this);
   }
 
   _LIBCPP_INLINE_VISIBILITY
-  any(any && __other) _NOEXCEPT : __h(nullptr)
+  any(any && __other) _NOEXCEPT : __h_(nullptr)
   {
-    if (__other.__h) __other.__call(_Action::_Move, this);
+    if (__other.__h_) __other.__call(_Action::_Move, this);
   }
 
   template <
@@ -284,19 +284,19 @@ public:
 
   // 6.3.3 any modifiers
   _LIBCPP_INLINE_VISIBILITY
-  void reset() _NOEXCEPT { if (__h) this->__call(_Action::_Destroy); }
+  void reset() _NOEXCEPT { if (__h_) this->__call(_Action::_Destroy); }
 
   _LIBCPP_INLINE_VISIBILITY
   void swap(any & __rhs) _NOEXCEPT;
 
   // 6.3.4 any observers
   _LIBCPP_INLINE_VISIBILITY
-  bool has_value() const _NOEXCEPT { return __h != nullptr; }
+  bool has_value() const _NOEXCEPT { return __h_ != nullptr; }
 
 #if !defined(_LIBCPP_NO_RTTI)
   _LIBCPP_INLINE_VISIBILITY
   const type_info & type() const _NOEXCEPT {
-    if (__h) {
+    if (__h_) {
         return *static_cast<type_info const *>(this->__call(_Action::_TypeInfo));
     } else {
         return typeid(void);
@@ -320,7 +320,7 @@ private:
                   type_info const * __info = nullptr,
                    const void* __fallback_info = nullptr) const
     {
-        return __h(__a, this, __other, __info, __fallback_info);
+        return __h_(__a, this, __other, __info, __fallback_info);
     }
 
     _LIBCPP_INLINE_VISIBILITY
@@ -328,7 +328,7 @@ private:
                   type_info const * __info = nullptr,
                   const void* __fallback_info = nullptr)
     {
-        return __h(__a, this, __other, __info, __fallback_info);
+        return __h_(__a, this, __other, __info, __fallback_info);
     }
 
     template <class>
@@ -344,8 +344,8 @@ private:
     friend add_pointer_t<_ValueType>
     any_cast(any *) _NOEXCEPT;
 
-    _HandleFuncPtr __h = nullptr;
-    _Storage __s;
+    _HandleFuncPtr __h_ = nullptr;
+    _Storage __s_;
 };
 
 namespace __any_imp
@@ -382,9 +382,9 @@ namespace __any_imp
         typedef allocator<_Tp> _Alloc;
         typedef allocator_traits<_Alloc> _ATraits;
         _Alloc __a;
-        _Tp * __ret = static_cast<_Tp*>(static_cast<void*>(&__dest.__s.__buf));
+        _Tp * __ret = static_cast<_Tp*>(static_cast<void*>(&__dest.__s_.__buf));
         _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
-        __dest.__h = &_SmallHandler::__handle;
+        __dest.__h_ = &_SmallHandler::__handle;
         return *__ret;
     }
 
@@ -394,21 +394,21 @@ namespace __any_imp
         typedef allocator<_Tp> _Alloc;
         typedef allocator_traits<_Alloc> _ATraits;
         _Alloc __a;
-        _Tp * __p = static_cast<_Tp *>(static_cast<void*>(&__this.__s.__buf));
+        _Tp * __p = static_cast<_Tp *>(static_cast<void*>(&__this.__s_.__buf));
         _ATraits::destroy(__a, __p);
-        __this.__h = nullptr;
+        __this.__h_ = nullptr;
     }
 
     _LIBCPP_INLINE_VISIBILITY
     static void __copy(any const & __this, any & __dest) {
         _SmallHandler::__create(__dest, *static_cast<_Tp const *>(
-            static_cast<void const *>(&__this.__s.__buf)));
+            static_cast<void const *>(&__this.__s_.__buf)));
     }
 
     _LIBCPP_INLINE_VISIBILITY
     static void __move(any & __this, any & __dest) {
         _SmallHandler::__create(__dest, _VSTD::move(
-            *static_cast<_Tp*>(static_cast<void*>(&__this.__s.__buf))));
+            *static_cast<_Tp*>(static_cast<void*>(&__this.__s_.__buf))));
         __destroy(__this);
     }
 
@@ -418,7 +418,7 @@ namespace __any_imp
                        const void* __fallback_id)
     {
         if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_id))
-            return static_cast<void*>(&__this.__s.__buf);
+            return static_cast<void*>(&__this.__s_.__buf);
         return nullptr;
     }
 
@@ -470,8 +470,8 @@ namespace __any_imp
         unique_ptr<_Tp, _Dp> __hold(_ATraits::allocate(__a, 1), _Dp(__a, 1));
         _Tp * __ret = __hold.get();
         _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
-        __dest.__s.__ptr = __hold.release();
-        __dest.__h = &_LargeHandler::__handle;
+        __dest.__s_.__ptr = __hold.release();
+        __dest.__h_ = &_LargeHandler::__handle;
         return *__ret;
     }
 
@@ -482,22 +482,22 @@ namespace __any_imp
         typedef allocator<_Tp> _Alloc;
         typedef allocator_traits<_Alloc> _ATraits;
         _Alloc __a;
-        _Tp * __p = static_cast<_Tp *>(__this.__s.__ptr);
+        _Tp * __p = static_cast<_Tp *>(__this.__s_.__ptr);
         _ATraits::destroy(__a, __p);
         _ATraits::deallocate(__a, __p, 1);
-        __this.__h = nullptr;
+        __this.__h_ = nullptr;
     }
 
     _LIBCPP_INLINE_VISIBILITY
     static void __copy(any const & __this, any & __dest) {
-        _LargeHandler::__create(__dest, *static_cast<_Tp const *>(__this.__s.__ptr));
+        _LargeHandler::__create(__dest, *static_cast<_Tp const *>(__this.__s_.__ptr));
     }
 
     _LIBCPP_INLINE_VISIBILITY
     static void __move(any & __this, any & __dest) {
-      __dest.__s.__ptr = __this.__s.__ptr;
-      __dest.__h = &_LargeHandler::__handle;
-      __this.__h = nullptr;
+      __dest.__s_.__ptr = __this.__s_.__ptr;
+      __dest.__h_ = &_LargeHandler::__handle;
+      __this.__h_ = nullptr;
     }
 
     _LIBCPP_INLINE_VISIBILITY
@@ -505,7 +505,7 @@ namespace __any_imp
                        void const* __fallback_info)
     {
         if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_info))
-            return static_cast<void*>(__this.__s.__ptr);
+            return static_cast<void*>(__this.__s_.__ptr);
         return nullptr;
 
     }
@@ -525,7 +525,7 @@ namespace __any_imp
 
 
 template <class _ValueType, class _Tp, class>
-any::any(_ValueType && __v) : __h(nullptr)
+any::any(_ValueType && __v) : __h_(nullptr)
 {
   __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_ValueType>(__v));
 }
@@ -567,16 +567,16 @@ void any::swap(any & __rhs) _NOEXCEPT
 {
     if (this == &__rhs)
       return;
-    if (__h && __rhs.__h) {
+    if (__h_ && __rhs.__h_) {
         any __tmp;
         __rhs.__call(_Action::_Move, &__tmp);
         this->__call(_Action::_Move, &__rhs);
         __tmp.__call(_Action::_Move, this);
     }
-    else if (__h) {
+    else if (__h_) {
         this->__call(_Action::_Move, &__rhs);
     }
-    else if (__rhs.__h) {
+    else if (__rhs.__h_) {
         __rhs.__call(_Action::_Move, this);
     }
 }
@@ -677,7 +677,7 @@ any_cast(any * __any) _NOEXCEPT
     static_assert(!is_reference<_ValueType>::value,
                   "_ValueType may not be a reference.");
     typedef typename add_pointer<_ValueType>::type _ReturnType;
-    if (__any && __any->__h) {
+    if (__any && __any->__h_) {
       void *__p = __any->__call(_Action::_Get, nullptr,
 #if !defined(_LIBCPP_NO_RTTI)
                           &typeid(_ValueType),

diff  --git a/libcxx/include/barrier b/libcxx/include/barrier
index 00518035283fe..d5104b5803d20 100644
--- a/libcxx/include/barrier
+++ b/libcxx/include/barrier
@@ -283,7 +283,7 @@ public:
 template<class _CompletionF = __empty_completion>
 class barrier {
 
-    __barrier_base<_CompletionF> __b;
+    __barrier_base<_CompletionF> __b_;
 public:
     using arrival_token = typename __barrier_base<_CompletionF>::arrival_token;
 
@@ -293,7 +293,7 @@ public:
 
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     barrier(ptr
diff _t __count, _CompletionF __completion = _CompletionF())
-        : __b(__count, _VSTD::move(__completion)) {
+        : __b_(__count, _VSTD::move(__completion)) {
     }
 
     barrier(barrier const&) = delete;
@@ -302,12 +302,12 @@ public:
     [[nodiscard]] _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     arrival_token arrive(ptr
diff _t __update = 1)
     {
-        return __b.arrive(__update);
+        return __b_.arrive(__update);
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void wait(arrival_token&& __phase) const
     {
-        __b.wait(_VSTD::move(__phase));
+        __b_.wait(_VSTD::move(__phase));
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void arrive_and_wait()
@@ -317,7 +317,7 @@ public:
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void arrive_and_drop()
     {
-        __b.arrive_and_drop();
+        __b_.arrive_and_drop();
     }
 };
 

diff  --git a/libcxx/include/codecvt b/libcxx/include/codecvt
index cbe5511b6f089..a724477b15548 100644
--- a/libcxx/include/codecvt
+++ b/libcxx/include/codecvt
@@ -81,9 +81,9 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8<wchar_t>
     : public codecvt<wchar_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
+    unsigned long __maxcode_;
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
-    codecvt_mode _Mode_;
+    codecvt_mode __mode_;
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 public:
     typedef wchar_t   intern_type;
@@ -94,8 +94,8 @@ _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<wchar_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 protected:
     result do_out(state_type& __st,
@@ -118,8 +118,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8<char16_t>
     : public codecvt<char16_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char16_t  intern_type;
     typedef char      extern_type;
@@ -128,8 +128,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char16_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -152,8 +152,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8<char32_t>
     : public codecvt<char32_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char32_t  intern_type;
     typedef char      extern_type;
@@ -162,8 +162,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char32_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -206,9 +206,9 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<wchar_t, false>
     : public codecvt<wchar_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
+    unsigned long __maxcode_;
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
-    codecvt_mode _Mode_;
+    codecvt_mode __mode_;
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 public:
     typedef wchar_t   intern_type;
@@ -219,8 +219,8 @@ _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<wchar_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 protected:
      result do_out(state_type& __st,
@@ -242,9 +242,9 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<wchar_t, true>
     : public codecvt<wchar_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
+    unsigned long __maxcode_;
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
-    codecvt_mode _Mode_;
+    codecvt_mode __mode_;
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 public:
     typedef wchar_t   intern_type;
@@ -255,8 +255,8 @@ _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<wchar_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 protected:
      result do_out(state_type& __st,
@@ -279,8 +279,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<char16_t, false>
     : public codecvt<char16_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char16_t  intern_type;
     typedef char      extern_type;
@@ -289,8 +289,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char16_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -313,8 +313,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<char16_t, true>
     : public codecvt<char16_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char16_t  intern_type;
     typedef char      extern_type;
@@ -323,8 +323,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char16_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -347,8 +347,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<char32_t, false>
     : public codecvt<char32_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char32_t  intern_type;
     typedef char      extern_type;
@@ -357,8 +357,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char32_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -381,8 +381,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf16<char32_t, true>
     : public codecvt<char32_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char32_t  intern_type;
     typedef char      extern_type;
@@ -391,8 +391,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char32_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -435,9 +435,9 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<wchar_t>
     : public codecvt<wchar_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
+    unsigned long __maxcode_;
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
-    codecvt_mode _Mode_;
+    codecvt_mode __mode_;
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 public:
     typedef wchar_t   intern_type;
@@ -448,8 +448,8 @@ _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<wchar_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 protected:
      result do_out(state_type& __st,
@@ -472,8 +472,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<char32_t>
     : public codecvt<char32_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char32_t  intern_type;
     typedef char      extern_type;
@@ -482,8 +482,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char32_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:
@@ -506,8 +506,8 @@ template <>
 class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<char16_t>
     : public codecvt<char16_t, char, mbstate_t>
 {
-    unsigned long _Maxcode_;
-    codecvt_mode _Mode_;
+    unsigned long __maxcode_;
+    codecvt_mode __mode_;
 public:
     typedef char16_t  intern_type;
     typedef char      extern_type;
@@ -516,8 +516,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     explicit __codecvt_utf8_utf16(size_t __refs, unsigned long __maxcode,
                             codecvt_mode __mode)
-        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(__maxcode),
-          _Mode_(__mode) {}
+        : codecvt<char16_t, char, mbstate_t>(__refs), __maxcode_(__maxcode),
+          __mode_(__mode) {}
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
 protected:

diff  --git a/libcxx/include/exception b/libcxx/include/exception
index 04057c3cbe3b4..98b355f9bdd98 100644
--- a/libcxx/include/exception
+++ b/libcxx/include/exception
@@ -116,11 +116,11 @@ struct __std_exception_data {
 
 class exception { // base of all library exceptions
 public:
-  exception() _NOEXCEPT : _Data() {}
+  exception() _NOEXCEPT : __data_() {}
 
-  explicit exception(char const* __message) _NOEXCEPT : _Data() {
-    _Data._What = __message;
-    _Data._DoFree = true;
+  explicit exception(char const* __message) _NOEXCEPT : __data_() {
+    __data_._What = __message;
+    __data_._DoFree = true;
   }
 
   exception(exception const&) _NOEXCEPT {}
@@ -129,10 +129,10 @@ public:
 
   virtual ~exception() _NOEXCEPT {}
 
-  virtual char const* what() const _NOEXCEPT { return _Data._What ? _Data._What : "Unknown exception"; }
+  virtual char const* what() const _NOEXCEPT { return __data_._What ? __data_._What : "Unknown exception"; }
 
 private:
-  __std_exception_data _Data;
+  __std_exception_data __data_;
 };
 
 class bad_exception : public exception {

diff  --git a/libcxx/include/experimental/functional b/libcxx/include/experimental/functional
index 21c590f650e41..873973d8acb09 100644
--- a/libcxx/include/experimental/functional
+++ b/libcxx/include/experimental/functional
@@ -132,24 +132,24 @@ class _BMSkipTable<_Key, _Value, _Hash, _BinaryPredicate, false> {
     typedef _Key   key_type;
 
     const _Value __default_value_;
-    std::unordered_map<_Key, _Value, _Hash, _BinaryPredicate> __table;
+    std::unordered_map<_Key, _Value, _Hash, _BinaryPredicate> __table_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
     _BMSkipTable(size_t __sz, _Value __default, _Hash __hf, _BinaryPredicate __pred)
-        : __default_value_(__default), __table(__sz, __hf, __pred) {}
+        : __default_value_(__default), __table_(__sz, __hf, __pred) {}
 
     _LIBCPP_INLINE_VISIBILITY
     void insert(const key_type &__key, value_type __val)
     {
-        __table [__key] = __val;    // Would skip_.insert (val) be better here?
+        __table_ [__key] = __val;    // Would skip_.insert (val) be better here?
     }
 
     _LIBCPP_INLINE_VISIBILITY
     value_type operator [](const key_type & __key) const
     {
-        auto __it = __table.find (__key);
-        return __it == __table.end() ? __default_value_ : __it->second;
+        auto __it = __table_.find (__key);
+        return __it == __table_.end() ? __default_value_ : __it->second;
     }
 };
 
@@ -163,25 +163,25 @@ private:
 
     typedef typename make_unsigned<key_type>::type unsigned_key_type;
     typedef std::array<value_type, 256> skip_map;
-    skip_map __table;
+    skip_map __table_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
     _BMSkipTable(size_t /*__sz*/, _Value __default, _Hash /*__hf*/, _BinaryPredicate /*__pred*/)
     {
-        std::fill_n(__table.begin(), __table.size(), __default);
+        std::fill_n(__table_.begin(), __table_.size(), __default);
     }
 
     _LIBCPP_INLINE_VISIBILITY
     void insert(key_type __key, value_type __val)
     {
-        __table[static_cast<unsigned_key_type>(__key)] = __val;
+        __table_[static_cast<unsigned_key_type>(__key)] = __val;
     }
 
     _LIBCPP_INLINE_VISIBILITY
     value_type operator [](key_type __key) const
     {
-        return __table[static_cast<unsigned_key_type>(__key)];
+        return __table_[static_cast<unsigned_key_type>(__key)];
     }
 };
 

diff  --git a/libcxx/include/experimental/iterator b/libcxx/include/experimental/iterator
index b5fd2994203ae..3e460d6a7f5db 100644
--- a/libcxx/include/experimental/iterator
+++ b/libcxx/include/experimental/iterator
@@ -82,19 +82,19 @@ public:
     typedef void                                 reference;
 
     ostream_joiner(ostream_type& __os, _Delim&& __d)
-        : __output_iter(_VSTD::addressof(__os)), __delim(_VSTD::move(__d)), __first(true) {}
+        : __output_iter_(_VSTD::addressof(__os)), __delim_(_VSTD::move(__d)), __first_(true) {}
 
     ostream_joiner(ostream_type& __os, const _Delim& __d)
-        : __output_iter(_VSTD::addressof(__os)), __delim(__d), __first(true) {}
+        : __output_iter_(_VSTD::addressof(__os)), __delim_(__d), __first_(true) {}
 
 
     template<typename _Tp>
     ostream_joiner& operator=(const _Tp& __v)
     {
-        if (!__first)
-            *__output_iter << __delim;
-        __first = false;
-        *__output_iter << __v;
+        if (!__first_)
+            *__output_iter_ << __delim_;
+        __first_ = false;
+        *__output_iter_ << __v;
         return *this;
     }
 
@@ -103,9 +103,9 @@ public:
     ostream_joiner& operator++(int) _NOEXCEPT { return *this; }
 
 private:
-    ostream_type*   __output_iter;
-    _Delim          __delim;
-    bool            __first;
+    ostream_type*   __output_iter_;
+    _Delim          __delim_;
+    bool            __first_;
 };
 
 

diff  --git a/libcxx/include/latch b/libcxx/include/latch
index 85936750b4c11..ff17f8453ea50 100644
--- a/libcxx/include/latch
+++ b/libcxx/include/latch
@@ -64,7 +64,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 class latch
 {
-    __atomic_base<ptr
diff _t> __a;
+    __atomic_base<ptr
diff _t> __a_;
 
 public:
     static constexpr ptr
diff _t max() noexcept {
@@ -72,7 +72,7 @@ public:
     }
 
     inline _LIBCPP_INLINE_VISIBILITY
-    constexpr explicit latch(ptr
diff _t __expected) : __a(__expected) { }
+    constexpr explicit latch(ptr
diff _t __expected) : __a_(__expected) { }
 
     ~latch() = default;
     latch(const latch&) = delete;
@@ -81,19 +81,19 @@ public:
     inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void count_down(ptr
diff _t __update = 1)
     {
-        auto const __old = __a.fetch_sub(__update, memory_order_release);
+        auto const __old = __a_.fetch_sub(__update, memory_order_release);
         if(__old == __update)
-            __a.notify_all();
+            __a_.notify_all();
     }
     inline _LIBCPP_INLINE_VISIBILITY
     bool try_wait() const noexcept
     {
-        return 0 == __a.load(memory_order_acquire);
+        return 0 == __a_.load(memory_order_acquire);
     }
     inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void wait() const
     {
-        __cxx_atomic_wait(&__a.__a_, [&]() -> bool {
+        __cxx_atomic_wait(&__a_.__a_, [&]() -> bool {
             return try_wait();
         });
     }

diff  --git a/libcxx/include/map b/libcxx/include/map
index 8b21f482928a2..1e619b9132eba 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -619,46 +619,46 @@ public:
 template <class _Key, class _CP, class _Compare>
 class __map_value_compare<_Key, _CP, _Compare, false>
 {
-    _Compare comp;
+    _Compare __comp_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
     __map_value_compare()
         _NOEXCEPT_(is_nothrow_default_constructible<_Compare>::value)
-        : comp() {}
+        : __comp_() {}
     _LIBCPP_INLINE_VISIBILITY
     __map_value_compare(_Compare __c)
         _NOEXCEPT_(is_nothrow_copy_constructible<_Compare>::value)
-        : comp(__c) {}
+        : __comp_(__c) {}
     _LIBCPP_INLINE_VISIBILITY
-    const _Compare& key_comp() const _NOEXCEPT {return comp;}
+    const _Compare& key_comp() const _NOEXCEPT {return __comp_;}
 
     _LIBCPP_INLINE_VISIBILITY
     bool operator()(const _CP& __x, const _CP& __y) const
-        {return comp(__x.__get_value().first, __y.__get_value().first);}
+        {return __comp_(__x.__get_value().first, __y.__get_value().first);}
     _LIBCPP_INLINE_VISIBILITY
     bool operator()(const _CP& __x, const _Key& __y) const
-        {return comp(__x.__get_value().first, __y);}
+        {return __comp_(__x.__get_value().first, __y);}
     _LIBCPP_INLINE_VISIBILITY
     bool operator()(const _Key& __x, const _CP& __y) const
-        {return comp(__x, __y.__get_value().first);}
+        {return __comp_(__x, __y.__get_value().first);}
     void swap(__map_value_compare& __y)
         _NOEXCEPT_(__is_nothrow_swappable<_Compare>::value)
     {
         using _VSTD::swap;
-        swap(comp, __y.comp);
+        swap(__comp_, __y.__comp_);
     }
 
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     bool operator()(const _K2& __x, const _CP& __y) const
-        {return comp(__x, __y.__get_value().first);}
+        {return __comp_(__x, __y.__get_value().first);}
 
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     bool operator()(const _CP& __x, const _K2& __y) const
-        {return comp(__x.__get_value().first, __y);}
+        {return __comp_(__x.__get_value().first, __y);}
 #endif
 };
 
@@ -738,16 +738,16 @@ struct _LIBCPP_STANDALONE_DEBUG __value_type
     typedef pair<key_type&&, mapped_type&&>          __nc_rref_pair_type;
 
 private:
-    value_type __cc;
+    value_type __cc_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
     value_type& __get_value()
     {
 #if _LIBCPP_STD_VER > 14
-        return *_VSTD::launder(_VSTD::addressof(__cc));
+        return *_VSTD::launder(_VSTD::addressof(__cc_));
 #else
-        return __cc;
+        return __cc_;
 #endif
     }
 
@@ -755,9 +755,9 @@ public:
     const value_type& __get_value() const
     {
 #if _LIBCPP_STD_VER > 14
-        return *_VSTD::launder(_VSTD::addressof(__cc));
+        return *_VSTD::launder(_VSTD::addressof(__cc_));
 #else
-        return __cc;
+        return __cc_;
 #endif
     }
 
@@ -818,13 +818,13 @@ struct __value_type
     typedef pair<const key_type, mapped_type>        value_type;
 
 private:
-    value_type __cc;
+    value_type __cc_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
-    value_type& __get_value() { return __cc; }
+    value_type& __get_value() { return __cc_; }
     _LIBCPP_INLINE_VISIBILITY
-    const value_type& __get_value() const { return __cc; }
+    const value_type& __get_value() const { return __cc_; }
 
 private:
    __value_type();

diff  --git a/libcxx/include/semaphore b/libcxx/include/semaphore
index 228cf773f0fd7..3e4f51cae58fc 100644
--- a/libcxx/include/semaphore
+++ b/libcxx/include/semaphore
@@ -80,31 +80,31 @@ functions. It avoids contention against users' own use of those facilities.
 
 class __atomic_semaphore_base
 {
-    __atomic_base<ptr
diff _t> __a;
+    __atomic_base<ptr
diff _t> __a_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
-    constexpr explicit __atomic_semaphore_base(ptr
diff _t __count) : __a(__count)
+    constexpr explicit __atomic_semaphore_base(ptr
diff _t __count) : __a_(__count)
     {
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void release(ptr
diff _t __update = 1)
     {
-        if(0 < __a.fetch_add(__update, memory_order_release))
+        if(0 < __a_.fetch_add(__update, memory_order_release))
             ;
         else if(__update > 1)
-            __a.notify_all();
+            __a_.notify_all();
         else
-            __a.notify_one();
+            __a_.notify_one();
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void acquire()
     {
         auto const __test_fn = [this]() -> bool {
-            auto __old = __a.load(memory_order_relaxed);
-            return (__old != 0) && __a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed);
+            auto __old = __a_.load(memory_order_relaxed);
+            return (__old != 0) && __a_.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed);
         };
-        __cxx_atomic_wait(&__a.__a_, __test_fn);
+        __cxx_atomic_wait(&__a_.__a_, __test_fn);
     }
     template <class Rep, class Period>
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
@@ -118,11 +118,11 @@ public:
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     bool try_acquire()
     {
-        auto __old = __a.load(memory_order_acquire);
+        auto __old = __a_.load(memory_order_acquire);
         while (true) {
             if (__old == 0)
                 return false;
-            if (__a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
+            if (__a_.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
                 return true;
         }
     }
@@ -133,7 +133,7 @@ public:
 template<ptr
diff _t __least_max_value = _LIBCPP_SEMAPHORE_MAX>
 class counting_semaphore
 {
-    __atomic_semaphore_base __semaphore;
+    __atomic_semaphore_base __semaphore_;
 
 public:
     static constexpr ptr
diff _t max() noexcept {
@@ -141,7 +141,7 @@ public:
     }
 
     _LIBCPP_INLINE_VISIBILITY
-    constexpr explicit counting_semaphore(ptr
diff _t __count) : __semaphore(__count) { }
+    constexpr explicit counting_semaphore(ptr
diff _t __count) : __semaphore_(__count) { }
     ~counting_semaphore() = default;
 
     counting_semaphore(const counting_semaphore&) = delete;
@@ -150,23 +150,23 @@ public:
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void release(ptr
diff _t __update = 1)
     {
-        __semaphore.release(__update);
+        __semaphore_.release(__update);
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     void acquire()
     {
-        __semaphore.acquire();
+        __semaphore_.acquire();
     }
     template<class Rep, class Period>
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time)
     {
-        return __semaphore.try_acquire_for(chrono::duration_cast<chrono::nanoseconds>(__rel_time));
+        return __semaphore_.try_acquire_for(chrono::duration_cast<chrono::nanoseconds>(__rel_time));
     }
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
     bool try_acquire()
     {
-        return __semaphore.try_acquire();
+        return __semaphore_.try_acquire();
     }
     template <class Clock, class Duration>
     _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY

diff  --git a/libcxx/include/shared_mutex b/libcxx/include/shared_mutex
index f85cf6ec4c4f2..e6773651ac619 100644
--- a/libcxx/include/shared_mutex
+++ b/libcxx/include/shared_mutex
@@ -180,23 +180,23 @@ __shared_mutex_base
 #if _LIBCPP_STD_VER > 14
 class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_mutex
 {
-    __shared_mutex_base __base;
+    __shared_mutex_base __base_;
 public:
-    _LIBCPP_INLINE_VISIBILITY shared_mutex() : __base() {}
+    _LIBCPP_INLINE_VISIBILITY shared_mutex() : __base_() {}
     _LIBCPP_INLINE_VISIBILITY ~shared_mutex() = default;
 
     shared_mutex(const shared_mutex&) = delete;
     shared_mutex& operator=(const shared_mutex&) = delete;
 
     // Exclusive ownership
-    _LIBCPP_INLINE_VISIBILITY void lock()     { return __base.lock(); }
-    _LIBCPP_INLINE_VISIBILITY bool try_lock() { return __base.try_lock(); }
-    _LIBCPP_INLINE_VISIBILITY void unlock()   { return __base.unlock(); }
+    _LIBCPP_INLINE_VISIBILITY void lock()     { return __base_.lock(); }
+    _LIBCPP_INLINE_VISIBILITY bool try_lock() { return __base_.try_lock(); }
+    _LIBCPP_INLINE_VISIBILITY void unlock()   { return __base_.unlock(); }
 
     // Shared ownership
-    _LIBCPP_INLINE_VISIBILITY void lock_shared()     { return __base.lock_shared(); }
-    _LIBCPP_INLINE_VISIBILITY bool try_lock_shared() { return __base.try_lock_shared(); }
-    _LIBCPP_INLINE_VISIBILITY void unlock_shared()   { return __base.unlock_shared(); }
+    _LIBCPP_INLINE_VISIBILITY void lock_shared()     { return __base_.lock_shared(); }
+    _LIBCPP_INLINE_VISIBILITY bool try_lock_shared() { return __base_.try_lock_shared(); }
+    _LIBCPP_INLINE_VISIBILITY void unlock_shared()   { return __base_.unlock_shared(); }
 
 //     typedef __shared_mutex_base::native_handle_type native_handle_type;
 //     _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() { return __base::unlock_shared(); }
@@ -206,7 +206,7 @@ public:
 
 class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_timed_mutex
 {
-    __shared_mutex_base __base;
+    __shared_mutex_base __base_;
 public:
     shared_timed_mutex();
     _LIBCPP_INLINE_VISIBILITY ~shared_timed_mutex() = default;
@@ -252,30 +252,30 @@ bool
 shared_timed_mutex::try_lock_until(
                         const chrono::time_point<_Clock, _Duration>& __abs_time)
 {
-    unique_lock<mutex> __lk(__base.__mut_);
-    if (__base.__state_ & __base.__write_entered_)
+    unique_lock<mutex> __lk(__base_.__mut_);
+    if (__base_.__state_ & __base_.__write_entered_)
     {
         while (true)
         {
-            cv_status __status = __base.__gate1_.wait_until(__lk, __abs_time);
-            if ((__base.__state_ & __base.__write_entered_) == 0)
+            cv_status __status = __base_.__gate1_.wait_until(__lk, __abs_time);
+            if ((__base_.__state_ & __base_.__write_entered_) == 0)
                 break;
             if (__status == cv_status::timeout)
                 return false;
         }
     }
-    __base.__state_ |= __base.__write_entered_;
-    if (__base.__state_ & __base.__n_readers_)
+    __base_.__state_ |= __base_.__write_entered_;
+    if (__base_.__state_ & __base_.__n_readers_)
     {
         while (true)
         {
-            cv_status __status = __base.__gate2_.wait_until(__lk, __abs_time);
-            if ((__base.__state_ & __base.__n_readers_) == 0)
+            cv_status __status = __base_.__gate2_.wait_until(__lk, __abs_time);
+            if ((__base_.__state_ & __base_.__n_readers_) == 0)
                 break;
             if (__status == cv_status::timeout)
             {
-                __base.__state_ &= ~__base.__write_entered_;
-                __base.__gate1_.notify_all();
+                __base_.__state_ &= ~__base_.__write_entered_;
+                __base_.__gate1_.notify_all();
                 return false;
             }
         }
@@ -288,22 +288,22 @@ bool
 shared_timed_mutex::try_lock_shared_until(
                         const chrono::time_point<_Clock, _Duration>& __abs_time)
 {
-    unique_lock<mutex> __lk(__base.__mut_);
-    if ((__base.__state_ & __base.__write_entered_) || (__base.__state_ & __base.__n_readers_) == __base.__n_readers_)
+    unique_lock<mutex> __lk(__base_.__mut_);
+    if ((__base_.__state_ & __base_.__write_entered_) || (__base_.__state_ & __base_.__n_readers_) == __base_.__n_readers_)
     {
         while (true)
         {
-            cv_status status = __base.__gate1_.wait_until(__lk, __abs_time);
-            if ((__base.__state_ & __base.__write_entered_) == 0 &&
-                                       (__base.__state_ & __base.__n_readers_) < __base.__n_readers_)
+            cv_status status = __base_.__gate1_.wait_until(__lk, __abs_time);
+            if ((__base_.__state_ & __base_.__write_entered_) == 0 &&
+                                       (__base_.__state_ & __base_.__n_readers_) < __base_.__n_readers_)
                 break;
             if (status == cv_status::timeout)
                 return false;
         }
     }
-    unsigned __num_readers = (__base.__state_ & __base.__n_readers_) + 1;
-    __base.__state_ &= ~__base.__n_readers_;
-    __base.__state_ |= __num_readers;
+    unsigned __num_readers = (__base_.__state_ & __base_.__n_readers_) + 1;
+    __base_.__state_ &= ~__base_.__n_readers_;
+    __base_.__state_ |= __num_readers;
     return true;
 }
 

diff  --git a/libcxx/include/span b/libcxx/include/span
index 190c441fabc7b..42fbd9165259c 100644
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -227,7 +227,7 @@ public:
 
 // [span.cons], span constructors, copy, assignment, and destructor
     template <size_t _Sz = _Extent> requires(_Sz == 0)
-    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr} {}
+    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data_{nullptr} {}
 
     constexpr span           (const span&) noexcept = default;
     constexpr span& operator=(const span&) noexcept = default;
@@ -235,46 +235,46 @@ public:
     template <__span_compatible_iterator<element_type> _It>
     _LIBCPP_INLINE_VISIBILITY
     constexpr explicit span(_It __first, size_type __count)
-        : __data{_VSTD::to_address(__first)} {
+        : __data_{_VSTD::to_address(__first)} {
       (void)__count;
       _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (iterator, len)");
     }
 
     template <__span_compatible_iterator<element_type> _It, __span_compatible_sentinel_for<_It> _End>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr explicit span(_It __first, _End __last) : __data{_VSTD::to_address(__first)} {
+    constexpr explicit span(_It __first, _End __last) : __data_{_VSTD::to_address(__first)} {
       (void)__last;
       _LIBCPP_ASSERT((__last - __first >= 0), "invalid range in span's constructor (iterator, sentinel)");
       _LIBCPP_ASSERT(__last - __first == _Extent,
                      "invalid range in span's constructor (iterator, sentinel): last - first != extent");
     }
 
-    _LIBCPP_INLINE_VISIBILITY constexpr span(type_identity_t<element_type> (&__arr)[_Extent]) noexcept : __data{__arr} {}
+    _LIBCPP_INLINE_VISIBILITY constexpr span(type_identity_t<element_type> (&__arr)[_Extent]) noexcept : __data_{__arr} {}
 
     template <__span_array_convertible<element_type> _OtherElementType>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+    constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data_{__arr.data()} {}
 
     template <class _OtherElementType>
         requires __span_array_convertible<const _OtherElementType, element_type>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+    constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data_{__arr.data()} {}
 
     template <__span_compatible_range<element_type> _Range>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr explicit span(_Range&& __r) : __data{ranges::data(__r)} {
+    constexpr explicit span(_Range&& __r) : __data_{ranges::data(__r)} {
       _LIBCPP_ASSERT(ranges::size(__r) == _Extent, "size mismatch in span's constructor (range)");
     }
 
     template <__span_array_convertible<element_type> _OtherElementType>
     _LIBCPP_INLINE_VISIBILITY
         constexpr span(const span<_OtherElementType, _Extent>& __other)
-        : __data{__other.data()} {}
+        : __data_{__other.data()} {}
 
     template <__span_array_convertible<element_type> _OtherElementType>
     _LIBCPP_INLINE_VISIBILITY
         constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other) noexcept
-        : __data{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); }
+        : __data_{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); }
 
 
 //  ~span() noexcept = default;
@@ -341,22 +341,22 @@ public:
     _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept
     {
         _LIBCPP_ASSERT(__idx < size(), "span<T, N>::operator[](index): index out of range");
-        return __data[__idx];
+        return __data_[__idx];
     }
 
     _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept
     {
         _LIBCPP_ASSERT(!empty(), "span<T, N>::front() on empty span");
-        return __data[0];
+        return __data_[0];
     }
 
     _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept
     {
         _LIBCPP_ASSERT(!empty(), "span<T, N>::back() on empty span");
-        return __data[size()-1];
+        return __data_[size()-1];
     }
 
-    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data; }
+    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data_; }
 
 // [span.iter], span iterator support
     _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept {
@@ -383,7 +383,7 @@ public:
     { return span<byte, _Extent * sizeof(element_type)>{reinterpret_cast<byte *>(data()), size_bytes()}; }
 
 private:
-    pointer    __data;
+    pointer    __data_;
 };
 
 
@@ -409,7 +409,7 @@ public:
     static constexpr size_type extent = dynamic_extent;
 
 // [span.cons], span constructors, copy, assignment, and destructor
-    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr}, __size{0} {}
+    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data_{nullptr}, __size_{0} {}
 
     constexpr span           (const span&) noexcept = default;
     constexpr span& operator=(const span&) noexcept = default;
@@ -417,35 +417,35 @@ public:
     template <__span_compatible_iterator<element_type> _It>
     _LIBCPP_INLINE_VISIBILITY
     constexpr span(_It __first, size_type __count)
-        : __data{_VSTD::to_address(__first)}, __size{__count} {}
+        : __data_{_VSTD::to_address(__first)}, __size_{__count} {}
 
     template <__span_compatible_iterator<element_type> _It, __span_compatible_sentinel_for<_It> _End>
     _LIBCPP_INLINE_VISIBILITY constexpr span(_It __first, _End __last)
-        : __data(_VSTD::to_address(__first)), __size(__last - __first) {
+        : __data_(_VSTD::to_address(__first)), __size_(__last - __first) {
       _LIBCPP_ASSERT(__last - __first >= 0, "invalid range in span's constructor (iterator, sentinel)");
     }
 
     template <size_t _Sz>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(type_identity_t<element_type> (&__arr)[_Sz]) noexcept : __data{__arr}, __size{_Sz} {}
+    constexpr span(type_identity_t<element_type> (&__arr)[_Sz]) noexcept : __data_{__arr}, __size_{_Sz} {}
 
     template <__span_array_convertible<element_type> _OtherElementType, size_t _Sz>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+    constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data_{__arr.data()}, __size_{_Sz} {}
 
     template <class _OtherElementType, size_t _Sz>
         requires __span_array_convertible<const _OtherElementType, element_type>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+    constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data_{__arr.data()}, __size_{_Sz} {}
 
     template <__span_compatible_range<element_type> _Range>
     _LIBCPP_INLINE_VISIBILITY
-    constexpr span(_Range&& __r) : __data(ranges::data(__r)), __size{ranges::size(__r)} {}
+    constexpr span(_Range&& __r) : __data_(ranges::data(__r)), __size_{ranges::size(__r)} {}
 
     template <__span_array_convertible<element_type> _OtherElementType, size_t _OtherExtent>
     _LIBCPP_INLINE_VISIBILITY
         constexpr span(const span<_OtherElementType, _OtherExtent>& __other)  noexcept
-        : __data{__other.data()}, __size{__other.size()} {}
+        : __data_{__other.data()}, __size_{__other.size()} {}
 
 //    ~span() noexcept = default;
 
@@ -500,30 +500,30 @@ public:
         return {data() + __offset, __count};
     }
 
-    _LIBCPP_INLINE_VISIBILITY constexpr size_type size()           const noexcept { return __size; }
-    _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes()     const noexcept { return __size * sizeof(element_type); }
-    [[nodiscard]] _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return __size == 0; }
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size()           const noexcept { return __size_; }
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes()     const noexcept { return __size_ * sizeof(element_type); }
+    [[nodiscard]] _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return __size_ == 0; }
 
     _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept
     {
         _LIBCPP_ASSERT(__idx < size(), "span<T>::operator[](index): index out of range");
-        return __data[__idx];
+        return __data_[__idx];
     }
 
     _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept
     {
         _LIBCPP_ASSERT(!empty(), "span<T>::front() on empty span");
-        return __data[0];
+        return __data_[0];
     }
 
     _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept
     {
         _LIBCPP_ASSERT(!empty(), "span<T>::back() on empty span");
-        return __data[size()-1];
+        return __data_[size()-1];
     }
 
 
-    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data; }
+    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data_; }
 
 // [span.iter], span iterator support
     _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept {
@@ -550,8 +550,8 @@ public:
     { return {reinterpret_cast<byte *>(data()), size_bytes()}; }
 
 private:
-    pointer   __data;
-    size_type __size;
+    pointer   __data_;
+    size_type __size_;
 };
 
 template <class _Tp, size_t _Extent>

diff  --git a/libcxx/include/string_view b/libcxx/include/string_view
index a964f13ab8d01..1e1abc780f884 100644
--- a/libcxx/include/string_view
+++ b/libcxx/include/string_view
@@ -295,7 +295,7 @@ public:
 
     // [string.view.cons], construct/copy
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {}
+    basic_string_view() _NOEXCEPT : __data_ (nullptr), __size_(0) {}
 
     _LIBCPP_INLINE_VISIBILITY
     basic_string_view(const basic_string_view&) _NOEXCEPT = default;
@@ -305,7 +305,7 @@ public:
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
-        : __data(__s), __size(__len)
+        : __data_(__s), __size_(__len)
     {
 #if _LIBCPP_STD_VER > 11
     _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
@@ -316,7 +316,7 @@ public:
     template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
       requires (is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
     constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
-       : __data(_VSTD::to_address(__begin)), __size(__end - __begin)
+       : __data_(_VSTD::to_address(__begin)), __size_(__end - __begin)
     {
       _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
     }
@@ -338,12 +338,12 @@ public:
         } || is_same_v<typename remove_reference_t<_Range>::traits_type, _Traits>)
       )
     constexpr explicit _LIBCPP_HIDE_FROM_ABI
-    basic_string_view(_Range&& __r) : __data(ranges::data(__r)), __size(ranges::size(__r)) {}
+    basic_string_view(_Range&& __r) : __data_(ranges::data(__r)), __size_(ranges::size(__r)) {}
 #endif // _LIBCPP_STD_VER > 20
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     basic_string_view(const _CharT* __s)
-        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
+        : __data_(__s), __size_(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
 
 #if _LIBCPP_STD_VER > 20
     basic_string_view(nullptr_t) = delete;
@@ -357,10 +357,10 @@ public:
     const_iterator end()    const _NOEXCEPT { return cend(); }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    const_iterator cbegin() const _NOEXCEPT { return __data; }
+    const_iterator cbegin() const _NOEXCEPT { return __data_; }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    const_iterator cend()   const _NOEXCEPT { return __data + __size; }
+    const_iterator cend()   const _NOEXCEPT { return __data_ + __size_; }
 
     _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_INLINE_VISIBILITY
     const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
@@ -376,72 +376,72 @@ public:
 
     // [string.view.capacity], capacity
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    size_type size()     const _NOEXCEPT { return __size; }
+    size_type size()     const _NOEXCEPT { return __size_; }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    size_type length()   const _NOEXCEPT { return __size; }
+    size_type length()   const _NOEXCEPT { return __size_; }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max() / sizeof(value_type); }
 
     _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    bool empty()         const _NOEXCEPT { return __size == 0; }
+    bool empty()         const _NOEXCEPT { return __size_ == 0; }
 
     // [string.view.access], element access
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     const_reference operator[](size_type __pos) const _NOEXCEPT {
-      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos];
+      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data_[__pos];
     }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     const_reference at(size_type __pos) const
     {
         return __pos >= size()
-            ? (__throw_out_of_range("string_view::at"), __data[0])
-            : __data[__pos];
+            ? (__throw_out_of_range("string_view::at"), __data_[0])
+            : __data_[__pos];
     }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     const_reference front() const _NOEXCEPT
     {
-        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
+        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data_[0];
     }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     const_reference back() const _NOEXCEPT
     {
-        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
+        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data_[__size_-1];
     }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    const_pointer data() const _NOEXCEPT { return __data; }
+    const_pointer data() const _NOEXCEPT { return __data_; }
 
     // [string.view.modifiers], modifiers:
     _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
     void remove_prefix(size_type __n) _NOEXCEPT
     {
         _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()");
-        __data += __n;
-        __size -= __n;
+        __data_ += __n;
+        __size_ -= __n;
     }
 
     _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
     void remove_suffix(size_type __n) _NOEXCEPT
     {
         _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()");
-        __size -= __n;
+        __size_ -= __n;
     }
 
     _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
     void swap(basic_string_view& __other) _NOEXCEPT
     {
-        const value_type *__p = __data;
-        __data = __other.__data;
-        __other.__data = __p;
+        const value_type *__p = __data_;
+        __data_ = __other.__data_;
+        __other.__data_ = __p;
 
-        size_type __sz = __size;
-        __size = __other.__size;
-        __other.__size = __sz;
+        size_type __sz = __size_;
+        __size_ = __other.__size_;
+        __other.__size_ = __sz;
     }
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -729,8 +729,8 @@ public:
 #endif
 
 private:
-    const   value_type* __data;
-    size_type           __size;
+    const   value_type* __data_;
+    size_type           __size_;
 };
 
 #if _LIBCPP_STD_VER > 17

diff  --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
index 07312453ccbbb..e0d659a0615e7 100644
--- a/libcxx/include/unordered_map
+++ b/libcxx/include/unordered_map
@@ -822,16 +822,16 @@ struct _LIBCPP_STANDALONE_DEBUG __hash_value_type
     typedef pair<key_type&&, mapped_type&&>          __nc_rref_pair_type;
 
 private:
-    value_type __cc;
+    value_type __cc_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
     value_type& __get_value()
     {
 #if _LIBCPP_STD_VER > 14
-        return *_VSTD::launder(_VSTD::addressof(__cc));
+        return *_VSTD::launder(_VSTD::addressof(__cc_));
 #else
-        return __cc;
+        return __cc_;
 #endif
     }
 
@@ -839,9 +839,9 @@ public:
     const value_type& __get_value() const
     {
 #if _LIBCPP_STD_VER > 14
-        return *_VSTD::launder(_VSTD::addressof(__cc));
+        return *_VSTD::launder(_VSTD::addressof(__cc_));
 #else
-        return __cc;
+        return __cc_;
 #endif
     }
 
@@ -904,13 +904,13 @@ struct __hash_value_type
     typedef pair<const key_type, mapped_type>        value_type;
 
 private:
-    value_type __cc;
+    value_type __cc_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY
-    value_type& __get_value() { return __cc; }
+    value_type& __get_value() { return __cc_; }
     _LIBCPP_INLINE_VISIBILITY
-    const value_type& __get_value() const { return __cc; }
+    const value_type& __get_value() const { return __cc_; }
 
 private:
    ~__hash_value_type();

diff  --git a/libcxx/include/variant b/libcxx/include/variant
index 7f8bb4170e394..a4a3c5bfa868e 100644
--- a/libcxx/include/variant
+++ b/libcxx/include/variant
@@ -490,7 +490,7 @@ struct __variant {
   template <size_t _Ip, class _Vp>
   _LIBCPP_HIDE_FROM_ABI
   static constexpr auto&& __get_alt(_Vp&& __v) {
-    return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl);
+    return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl_);
   }
 };
 
@@ -617,7 +617,7 @@ struct __variant {
   __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
     return __base::__visit_alt_at(__index,
                                   _VSTD::forward<_Visitor>(__visitor),
-                                  _VSTD::forward<_Vs>(__vs).__impl...);
+                                  _VSTD::forward<_Vs>(__vs).__impl_...);
   }
 
   template <class _Visitor, class... _Vs>
@@ -626,7 +626,7 @@ struct __variant {
                                               _Vs&&... __vs) {
     return __base::__visit_alt(
         _VSTD::forward<_Visitor>(__visitor),
-        _VSTD::__as_variant(_VSTD::forward<_Vs>(__vs)).__impl...);
+        _VSTD::__as_variant(_VSTD::forward<_Vs>(__vs)).__impl_...);
   }
 
   template <class _Visitor, class... _Vs>
@@ -1309,7 +1309,7 @@ public:
                         int> = 0>
   _LIBCPP_HIDE_FROM_ABI
   constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)
-      : __impl(in_place_index<0>) {}
+      : __impl_(in_place_index<0>) {}
 
   variant(const variant&) = default;
   variant(variant&&) = default;
@@ -1326,7 +1326,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI
   constexpr variant(_Arg&& __arg) noexcept(
       is_nothrow_constructible_v<_Tp, _Arg>)
-      : __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
+      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
 
   template <size_t _Ip, class... _Args,
             class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
@@ -1336,7 +1336,7 @@ public:
   explicit constexpr variant(
       in_place_index_t<_Ip>,
       _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
-      : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
+      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
 
   template <
       size_t _Ip,
@@ -1352,7 +1352,7 @@ public:
       initializer_list<_Up> __il,
       _Args&&... __args) noexcept(
       is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
-      : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
+      : __impl_(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
 
   template <
       class _Tp,
@@ -1363,7 +1363,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI
   explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(
       is_nothrow_constructible_v<_Tp, _Args...>)
-      : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
+      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
 
   template <
       class _Tp,
@@ -1379,7 +1379,7 @@ public:
       initializer_list<_Up> __il,
       _Args&&... __args) noexcept(
       is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)
-      : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
+      : __impl_(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
 
   ~variant() = default;
 
@@ -1398,7 +1398,7 @@ public:
   variant& operator=(_Arg&& __arg) noexcept(
       is_nothrow_assignable_v<_Tp&, _Arg> &&
       is_nothrow_constructible_v<_Tp, _Arg>) {
-    __impl.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg));
+    __impl_.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg));
     return *this;
   }
 
@@ -1410,7 +1410,7 @@ public:
       enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
   _LIBCPP_HIDE_FROM_ABI
   _Tp& emplace(_Args&&... __args) {
-    return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
+    return __impl_.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
   }
 
   template <
@@ -1423,7 +1423,7 @@ public:
                   int> = 0>
   _LIBCPP_HIDE_FROM_ABI
   _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
-    return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
+    return __impl_.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
   }
 
   template <
@@ -1434,7 +1434,7 @@ public:
       enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
   _LIBCPP_HIDE_FROM_ABI
   _Tp& emplace(_Args&&... __args) {
-    return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
+    return __impl_.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
   }
 
   template <
@@ -1447,16 +1447,16 @@ public:
                   int> = 0>
   _LIBCPP_HIDE_FROM_ABI
   _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
-    return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
+    return __impl_.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
   }
 
   _LIBCPP_HIDE_FROM_ABI
   constexpr bool valueless_by_exception() const noexcept {
-    return __impl.valueless_by_exception();
+    return __impl_.valueless_by_exception();
   }
 
   _LIBCPP_HIDE_FROM_ABI
-  constexpr size_t index() const noexcept { return __impl.index(); }
+  constexpr size_t index() const noexcept { return __impl_.index(); }
 
   template <
       bool _Dummy = true,
@@ -1469,11 +1469,11 @@ public:
   void swap(variant& __that) noexcept(
       __all<(is_nothrow_move_constructible_v<_Types> &&
              is_nothrow_swappable_v<_Types>)...>::value) {
-    __impl.__swap(__that.__impl);
+    __impl_.__swap(__that.__impl_);
   }
 
 private:
-  __variant_detail::__impl<_Types...> __impl;
+  __variant_detail::__impl<_Types...> __impl_;
 
   friend struct __variant_detail::__access::__variant;
   friend struct __variant_detail::__visitation::__variant;

diff  --git a/libcxx/src/locale.cpp b/libcxx/src/locale.cpp
index 02da95cc300ba..e5035bd73157e 100644
--- a/libcxx/src/locale.cpp
+++ b/libcxx/src/locale.cpp
@@ -739,25 +739,25 @@ locale::id::__init()
 
 collate_byname<char>::collate_byname(const char* n, size_t refs)
     : collate<char>(refs),
-      __l(newlocale(LC_ALL_MASK, n, 0))
+      __l_(newlocale(LC_ALL_MASK, n, 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("collate_byname<char>::collate_byname"
                             " failed to construct for " + string(n));
 }
 
 collate_byname<char>::collate_byname(const string& name, size_t refs)
     : collate<char>(refs),
-      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+      __l_(newlocale(LC_ALL_MASK, name.c_str(), 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("collate_byname<char>::collate_byname"
                             " failed to construct for " + name);
 }
 
 collate_byname<char>::~collate_byname()
 {
-    freelocale(__l);
+    freelocale(__l_);
 }
 
 int
@@ -766,7 +766,7 @@ collate_byname<char>::do_compare(const char_type* __lo1, const char_type* __hi1,
 {
     string_type lhs(__lo1, __hi1);
     string_type rhs(__lo2, __hi2);
-    int r = strcoll_l(lhs.c_str(), rhs.c_str(), __l);
+    int r = strcoll_l(lhs.c_str(), rhs.c_str(), __l_);
     if (r < 0)
         return -1;
     if (r > 0)
@@ -778,8 +778,8 @@ collate_byname<char>::string_type
 collate_byname<char>::do_transform(const char_type* lo, const char_type* hi) const
 {
     const string_type in(lo, hi);
-    string_type out(strxfrm_l(0, in.c_str(), 0, __l), char());
-    strxfrm_l(const_cast<char*>(out.c_str()), in.c_str(), out.size()+1, __l);
+    string_type out(strxfrm_l(0, in.c_str(), 0, __l_), char());
+    strxfrm_l(const_cast<char*>(out.c_str()), in.c_str(), out.size()+1, __l_);
     return out;
 }
 
@@ -788,25 +788,25 @@ collate_byname<char>::do_transform(const char_type* lo, const char_type* hi) con
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 collate_byname<wchar_t>::collate_byname(const char* n, size_t refs)
     : collate<wchar_t>(refs),
-      __l(newlocale(LC_ALL_MASK, n, 0))
+      __l_(newlocale(LC_ALL_MASK, n, 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("collate_byname<wchar_t>::collate_byname(size_t refs)"
                             " failed to construct for " + string(n));
 }
 
 collate_byname<wchar_t>::collate_byname(const string& name, size_t refs)
     : collate<wchar_t>(refs),
-      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+      __l_(newlocale(LC_ALL_MASK, name.c_str(), 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("collate_byname<wchar_t>::collate_byname(size_t refs)"
                             " failed to construct for " + name);
 }
 
 collate_byname<wchar_t>::~collate_byname()
 {
-    freelocale(__l);
+    freelocale(__l_);
 }
 
 int
@@ -815,7 +815,7 @@ collate_byname<wchar_t>::do_compare(const char_type* __lo1, const char_type* __h
 {
     string_type lhs(__lo1, __hi1);
     string_type rhs(__lo2, __hi2);
-    int r = wcscoll_l(lhs.c_str(), rhs.c_str(), __l);
+    int r = wcscoll_l(lhs.c_str(), rhs.c_str(), __l_);
     if (r < 0)
         return -1;
     if (r > 0)
@@ -827,8 +827,8 @@ collate_byname<wchar_t>::string_type
 collate_byname<wchar_t>::do_transform(const char_type* lo, const char_type* hi) const
 {
     const string_type in(lo, hi);
-    string_type out(wcsxfrm_l(0, in.c_str(), 0, __l), wchar_t());
-    wcsxfrm_l(const_cast<wchar_t*>(out.c_str()), in.c_str(), out.size()+1, __l);
+    string_type out(wcsxfrm_l(0, in.c_str(), 0, __l_), wchar_t());
+    wcsxfrm_l(const_cast<wchar_t*>(out.c_str()), in.c_str(), out.size()+1, __l_);
     return out;
 }
 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
@@ -1286,52 +1286,52 @@ ctype<char>::__classic_upper_table() _NOEXCEPT
 
 ctype_byname<char>::ctype_byname(const char* name, size_t refs)
     : ctype<char>(0, false, refs),
-      __l(newlocale(LC_ALL_MASK, name, 0))
+      __l_(newlocale(LC_ALL_MASK, name, 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("ctype_byname<char>::ctype_byname"
                             " failed to construct for " + string(name));
 }
 
 ctype_byname<char>::ctype_byname(const string& name, size_t refs)
     : ctype<char>(0, false, refs),
-      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+      __l_(newlocale(LC_ALL_MASK, name.c_str(), 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("ctype_byname<char>::ctype_byname"
                             " failed to construct for " + name);
 }
 
 ctype_byname<char>::~ctype_byname()
 {
-    freelocale(__l);
+    freelocale(__l_);
 }
 
 char
 ctype_byname<char>::do_toupper(char_type c) const
 {
-    return static_cast<char>(toupper_l(static_cast<unsigned char>(c), __l));
+    return static_cast<char>(toupper_l(static_cast<unsigned char>(c), __l_));
 }
 
 const char*
 ctype_byname<char>::do_toupper(char_type* low, const char_type* high) const
 {
     for (; low != high; ++low)
-        *low = static_cast<char>(toupper_l(static_cast<unsigned char>(*low), __l));
+        *low = static_cast<char>(toupper_l(static_cast<unsigned char>(*low), __l_));
     return low;
 }
 
 char
 ctype_byname<char>::do_tolower(char_type c) const
 {
-    return static_cast<char>(tolower_l(static_cast<unsigned char>(c), __l));
+    return static_cast<char>(tolower_l(static_cast<unsigned char>(c), __l_));
 }
 
 const char*
 ctype_byname<char>::do_tolower(char_type* low, const char_type* high) const
 {
     for (; low != high; ++low)
-        *low = static_cast<char>(tolower_l(static_cast<unsigned char>(*low), __l));
+        *low = static_cast<char>(tolower_l(static_cast<unsigned char>(*low), __l_));
     return low;
 }
 
@@ -1340,45 +1340,45 @@ ctype_byname<char>::do_tolower(char_type* low, const char_type* high) const
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 ctype_byname<wchar_t>::ctype_byname(const char* name, size_t refs)
     : ctype<wchar_t>(refs),
-      __l(newlocale(LC_ALL_MASK, name, 0))
+      __l_(newlocale(LC_ALL_MASK, name, 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("ctype_byname<wchar_t>::ctype_byname"
                             " failed to construct for " + string(name));
 }
 
 ctype_byname<wchar_t>::ctype_byname(const string& name, size_t refs)
     : ctype<wchar_t>(refs),
-      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+      __l_(newlocale(LC_ALL_MASK, name.c_str(), 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("ctype_byname<wchar_t>::ctype_byname"
                             " failed to construct for " + name);
 }
 
 ctype_byname<wchar_t>::~ctype_byname()
 {
-    freelocale(__l);
+    freelocale(__l_);
 }
 
 bool
 ctype_byname<wchar_t>::do_is(mask m, char_type c) const
 {
 #ifdef _LIBCPP_WCTYPE_IS_MASK
-    return static_cast<bool>(iswctype_l(c, m, __l));
+    return static_cast<bool>(iswctype_l(c, m, __l_));
 #else
     bool result = false;
     wint_t ch = static_cast<wint_t>(c);
-    if ((m & space) == space) result |= (iswspace_l(ch, __l) != 0);
-    if ((m & print) == print) result |= (iswprint_l(ch, __l) != 0);
-    if ((m & cntrl) == cntrl) result |= (iswcntrl_l(ch, __l) != 0);
-    if ((m & upper) == upper) result |= (iswupper_l(ch, __l) != 0);
-    if ((m & lower) == lower) result |= (iswlower_l(ch, __l) != 0);
-    if ((m & alpha) == alpha) result |= (iswalpha_l(ch, __l) != 0);
-    if ((m & digit) == digit) result |= (iswdigit_l(ch, __l) != 0);
-    if ((m & punct) == punct) result |= (iswpunct_l(ch, __l) != 0);
-    if ((m & xdigit) == xdigit) result |= (iswxdigit_l(ch, __l) != 0);
-    if ((m & blank) == blank) result |= (iswblank_l(ch, __l) != 0);
+    if ((m & space) == space) result |= (iswspace_l(ch, __l_) != 0);
+    if ((m & print) == print) result |= (iswprint_l(ch, __l_) != 0);
+    if ((m & cntrl) == cntrl) result |= (iswcntrl_l(ch, __l_) != 0);
+    if ((m & upper) == upper) result |= (iswupper_l(ch, __l_) != 0);
+    if ((m & lower) == lower) result |= (iswlower_l(ch, __l_) != 0);
+    if ((m & alpha) == alpha) result |= (iswalpha_l(ch, __l_) != 0);
+    if ((m & digit) == digit) result |= (iswdigit_l(ch, __l_) != 0);
+    if ((m & punct) == punct) result |= (iswpunct_l(ch, __l_) != 0);
+    if ((m & xdigit) == xdigit) result |= (iswxdigit_l(ch, __l_) != 0);
+    if ((m & blank) == blank) result |= (iswblank_l(ch, __l_) != 0);
     return result;
 #endif
 }
@@ -1394,32 +1394,32 @@ ctype_byname<wchar_t>::do_is(const char_type* low, const char_type* high, mask*
         {
             *vec = 0;
             wint_t ch = static_cast<wint_t>(*low);
-            if (iswspace_l(ch, __l))
+            if (iswspace_l(ch, __l_))
                 *vec |= space;
 #ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_PRINT
-            if (iswprint_l(ch, __l))
+            if (iswprint_l(ch, __l_))
                 *vec |= print;
 #endif
-            if (iswcntrl_l(ch, __l))
+            if (iswcntrl_l(ch, __l_))
                 *vec |= cntrl;
-            if (iswupper_l(ch, __l))
+            if (iswupper_l(ch, __l_))
                 *vec |= upper;
-            if (iswlower_l(ch, __l))
+            if (iswlower_l(ch, __l_))
                 *vec |= lower;
 #ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA
-            if (iswalpha_l(ch, __l))
+            if (iswalpha_l(ch, __l_))
                 *vec |= alpha;
 #endif
-            if (iswdigit_l(ch, __l))
+            if (iswdigit_l(ch, __l_))
                 *vec |= digit;
-            if (iswpunct_l(ch, __l))
+            if (iswpunct_l(ch, __l_))
                 *vec |= punct;
 #ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_XDIGIT
-            if (iswxdigit_l(ch, __l))
+            if (iswxdigit_l(ch, __l_))
                 *vec |= xdigit;
 #endif
 #if !defined(__sun__)
-            if (iswblank_l(ch, __l))
+            if (iswblank_l(ch, __l_))
                 *vec |= blank;
 #endif
         }
@@ -1433,20 +1433,20 @@ ctype_byname<wchar_t>::do_scan_is(mask m, const char_type* low, const char_type*
     for (; low != high; ++low)
     {
 #ifdef _LIBCPP_WCTYPE_IS_MASK
-        if (iswctype_l(*low, m, __l))
+        if (iswctype_l(*low, m, __l_))
             break;
 #else
         wint_t ch = static_cast<wint_t>(*low);
-        if ((m & space) == space && iswspace_l(ch, __l)) break;
-        if ((m & print) == print && iswprint_l(ch, __l)) break;
-        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l)) break;
-        if ((m & upper) == upper && iswupper_l(ch, __l)) break;
-        if ((m & lower) == lower && iswlower_l(ch, __l)) break;
-        if ((m & alpha) == alpha && iswalpha_l(ch, __l)) break;
-        if ((m & digit) == digit && iswdigit_l(ch, __l)) break;
-        if ((m & punct) == punct && iswpunct_l(ch, __l)) break;
-        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l)) break;
-        if ((m & blank) == blank && iswblank_l(ch, __l)) break;
+        if ((m & space) == space && iswspace_l(ch, __l_)) break;
+        if ((m & print) == print && iswprint_l(ch, __l_)) break;
+        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l_)) break;
+        if ((m & upper) == upper && iswupper_l(ch, __l_)) break;
+        if ((m & lower) == lower && iswlower_l(ch, __l_)) break;
+        if ((m & alpha) == alpha && iswalpha_l(ch, __l_)) break;
+        if ((m & digit) == digit && iswdigit_l(ch, __l_)) break;
+        if ((m & punct) == punct && iswpunct_l(ch, __l_)) break;
+        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l_)) break;
+        if ((m & blank) == blank && iswblank_l(ch, __l_)) break;
 #endif
     }
     return low;
@@ -1458,20 +1458,20 @@ ctype_byname<wchar_t>::do_scan_not(mask m, const char_type* low, const char_type
     for (; low != high; ++low)
     {
 #ifdef _LIBCPP_WCTYPE_IS_MASK
-        if (!iswctype_l(*low, m, __l))
+        if (!iswctype_l(*low, m, __l_))
             break;
 #else
         wint_t ch = static_cast<wint_t>(*low);
-        if ((m & space) == space && iswspace_l(ch, __l)) continue;
-        if ((m & print) == print && iswprint_l(ch, __l)) continue;
-        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l)) continue;
-        if ((m & upper) == upper && iswupper_l(ch, __l)) continue;
-        if ((m & lower) == lower && iswlower_l(ch, __l)) continue;
-        if ((m & alpha) == alpha && iswalpha_l(ch, __l)) continue;
-        if ((m & digit) == digit && iswdigit_l(ch, __l)) continue;
-        if ((m & punct) == punct && iswpunct_l(ch, __l)) continue;
-        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l)) continue;
-        if ((m & blank) == blank && iswblank_l(ch, __l)) continue;
+        if ((m & space) == space && iswspace_l(ch, __l_)) continue;
+        if ((m & print) == print && iswprint_l(ch, __l_)) continue;
+        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l_)) continue;
+        if ((m & upper) == upper && iswupper_l(ch, __l_)) continue;
+        if ((m & lower) == lower && iswlower_l(ch, __l_)) continue;
+        if ((m & alpha) == alpha && iswalpha_l(ch, __l_)) continue;
+        if ((m & digit) == digit && iswdigit_l(ch, __l_)) continue;
+        if ((m & punct) == punct && iswpunct_l(ch, __l_)) continue;
+        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l_)) continue;
+        if ((m & blank) == blank && iswblank_l(ch, __l_)) continue;
         break;
 #endif
     }
@@ -1481,49 +1481,49 @@ ctype_byname<wchar_t>::do_scan_not(mask m, const char_type* low, const char_type
 wchar_t
 ctype_byname<wchar_t>::do_toupper(char_type c) const
 {
-    return towupper_l(c, __l);
+    return towupper_l(c, __l_);
 }
 
 const wchar_t*
 ctype_byname<wchar_t>::do_toupper(char_type* low, const char_type* high) const
 {
     for (; low != high; ++low)
-        *low = towupper_l(*low, __l);
+        *low = towupper_l(*low, __l_);
     return low;
 }
 
 wchar_t
 ctype_byname<wchar_t>::do_tolower(char_type c) const
 {
-    return towlower_l(c, __l);
+    return towlower_l(c, __l_);
 }
 
 const wchar_t*
 ctype_byname<wchar_t>::do_tolower(char_type* low, const char_type* high) const
 {
     for (; low != high; ++low)
-        *low = towlower_l(*low, __l);
+        *low = towlower_l(*low, __l_);
     return low;
 }
 
 wchar_t
 ctype_byname<wchar_t>::do_widen(char c) const
 {
-    return __libcpp_btowc_l(c, __l);
+    return __libcpp_btowc_l(c, __l_);
 }
 
 const char*
 ctype_byname<wchar_t>::do_widen(const char* low, const char* high, char_type* dest) const
 {
     for (; low != high; ++low, ++dest)
-        *dest = __libcpp_btowc_l(*low, __l);
+        *dest = __libcpp_btowc_l(*low, __l_);
     return low;
 }
 
 char
 ctype_byname<wchar_t>::do_narrow(char_type c, char dfault) const
 {
-    int r = __libcpp_wctob_l(c, __l);
+    int r = __libcpp_wctob_l(c, __l_);
     return (r != EOF) ? static_cast<char>(r) : dfault;
 }
 
@@ -1532,7 +1532,7 @@ ctype_byname<wchar_t>::do_narrow(const char_type* low, const char_type* high, ch
 {
     for (; low != high; ++low, ++dest)
     {
-        int r = __libcpp_wctob_l(*low, __l);
+        int r = __libcpp_wctob_l(*low, __l_);
         *dest = (r != EOF) ? static_cast<char>(r) : dfault;
     }
     return low;
@@ -1607,23 +1607,23 @@ locale::id codecvt<wchar_t, char, mbstate_t>::id;
 
 codecvt<wchar_t, char, mbstate_t>::codecvt(size_t refs)
     : locale::facet(refs),
-      __l(_LIBCPP_GET_C_LOCALE)
+      __l_(_LIBCPP_GET_C_LOCALE)
 {
 }
 
 codecvt<wchar_t, char, mbstate_t>::codecvt(const char* nm, size_t refs)
     : locale::facet(refs),
-      __l(newlocale(LC_ALL_MASK, nm, 0))
+      __l_(newlocale(LC_ALL_MASK, nm, 0))
 {
-    if (__l == 0)
+    if (__l_ == 0)
         __throw_runtime_error("codecvt_byname<wchar_t, char, mbstate_t>::codecvt_byname"
                             " failed to construct for " + string(nm));
 }
 
 codecvt<wchar_t, char, mbstate_t>::~codecvt()
 {
-    if (__l != _LIBCPP_GET_C_LOCALE)
-        freelocale(__l);
+    if (__l_ != _LIBCPP_GET_C_LOCALE)
+        freelocale(__l_);
 }
 
 codecvt<wchar_t, char, mbstate_t>::result
@@ -1643,13 +1643,13 @@ codecvt<wchar_t, char, mbstate_t>::do_out(state_type& st,
         // save state in case it is needed to recover to_nxt on error
         mbstate_t save_state = st;
         size_t n = __libcpp_wcsnrtombs_l(to, &frm_nxt, static_cast<size_t>(fend-frm),
-                                     static_cast<size_t>(to_end-to), &st, __l);
+                                     static_cast<size_t>(to_end-to), &st, __l_);
         if (n == size_t(-1))
         {
             // need to recover to_nxt
             for (to_nxt = to; frm != frm_nxt; ++frm)
             {
-                n = __libcpp_wcrtomb_l(to_nxt, *frm, &save_state, __l);
+                n = __libcpp_wcrtomb_l(to_nxt, *frm, &save_state, __l_);
                 if (n == size_t(-1))
                     break;
                 to_nxt += n;
@@ -1666,7 +1666,7 @@ codecvt<wchar_t, char, mbstate_t>::do_out(state_type& st,
         {
             // Try to write the terminating null
             extern_type tmp[MB_LEN_MAX];
-            n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l);
+            n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l_);
             if (n == size_t(-1))  // on error
                 return error;
             if (n > static_cast<size_t>(to_end-to_nxt))  // is there room?
@@ -1700,14 +1700,14 @@ codecvt<wchar_t, char, mbstate_t>::do_in(state_type& st,
         // save state in case it is needed to recover to_nxt on error
         mbstate_t save_state = st;
         size_t n = __libcpp_mbsnrtowcs_l(to, &frm_nxt, static_cast<size_t>(fend-frm),
-                                     static_cast<size_t>(to_end-to), &st, __l);
+                                     static_cast<size_t>(to_end-to), &st, __l_);
         if (n == size_t(-1))
         {
             // need to recover to_nxt
             for (to_nxt = to; frm != frm_nxt; ++to_nxt)
             {
                 n = __libcpp_mbrtowc_l(to_nxt, frm, static_cast<size_t>(fend-frm),
-                                   &save_state, __l);
+                                   &save_state, __l_);
                 switch (n)
                 {
                 case 0:
@@ -1735,7 +1735,7 @@ codecvt<wchar_t, char, mbstate_t>::do_in(state_type& st,
         if (fend != frm_end)  // set up next null terminated sequence
         {
             // Try to write the terminating null
-            n = __libcpp_mbrtowc_l(to_nxt, frm_nxt, 1, &st, __l);
+            n = __libcpp_mbrtowc_l(to_nxt, frm_nxt, 1, &st, __l_);
             if (n != 0)  // on error
                 return error;
             ++to_nxt;
@@ -1755,7 +1755,7 @@ codecvt<wchar_t, char, mbstate_t>::do_unshift(state_type& st,
 {
     to_nxt = to;
     extern_type tmp[MB_LEN_MAX];
-    size_t n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l);
+    size_t n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l_);
     if (n == size_t(-1) || n == 0)  // on error
         return error;
     --n;
@@ -1769,11 +1769,11 @@ codecvt<wchar_t, char, mbstate_t>::do_unshift(state_type& st,
 int
 codecvt<wchar_t, char, mbstate_t>::do_encoding() const noexcept
 {
-    if (__libcpp_mbtowc_l(nullptr, nullptr, MB_LEN_MAX, __l) != 0)
+    if (__libcpp_mbtowc_l(nullptr, nullptr, MB_LEN_MAX, __l_) != 0)
         return -1;
 
     // stateless encoding
-    if (__l == 0 || __libcpp_mb_cur_max_l(__l) == 1)  // there are no known constant length encodings
+    if (__l_ == 0 || __libcpp_mb_cur_max_l(__l_) == 1)  // there are no known constant length encodings
         return 1;                // which take more than 1 char to form a wchar_t
     return 0;
 }
@@ -1791,7 +1791,7 @@ codecvt<wchar_t, char, mbstate_t>::do_length(state_type& st,
     int nbytes = 0;
     for (size_t nwchar_t = 0; nwchar_t < mx && frm != frm_end; ++nwchar_t)
     {
-        size_t n = __libcpp_mbrlen_l(frm, static_cast<size_t>(frm_end-frm), &st, __l);
+        size_t n = __libcpp_mbrlen_l(frm, static_cast<size_t>(frm_end-frm), &st, __l_);
         switch (n)
         {
         case 0:
@@ -1813,7 +1813,7 @@ codecvt<wchar_t, char, mbstate_t>::do_length(state_type& st,
 int
 codecvt<wchar_t, char, mbstate_t>::do_max_length() const noexcept
 {
-    return __l == 0 ? 1 : static_cast<int>(__libcpp_mb_cur_max_l(__l));
+    return __l_ == 0 ? 1 : static_cast<int>(__libcpp_mb_cur_max_l(__l_));
 }
 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
@@ -3545,10 +3545,10 @@ __codecvt_utf8<wchar_t>::do_out(state_type&,
     uint8_t* _to_nxt = _to;
 #if defined(_LIBCPP_SHORT_WCHAR)
     result r = ucs2_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
 #else
     result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3568,13 +3568,13 @@ __codecvt_utf8<wchar_t>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf8_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
 #else
     uint32_t* _to = reinterpret_cast<uint32_t*>(to);
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3608,9 +3608,9 @@ __codecvt_utf8<wchar_t>::do_length(state_type&,
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
 #if defined(_LIBCPP_SHORT_WCHAR)
-    return utf8_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #else
-    return utf8_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #endif
 }
 
@@ -3619,11 +3619,11 @@ int
 __codecvt_utf8<wchar_t>::do_max_length() const noexcept
 {
 #if defined(_LIBCPP_SHORT_WCHAR)
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 3;
 #else
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 7;
     return 4;
 #endif
@@ -3644,7 +3644,7 @@ __codecvt_utf8<char16_t>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs2_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -3662,7 +3662,7 @@ __codecvt_utf8<char16_t>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf8_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -3694,14 +3694,14 @@ __codecvt_utf8<char16_t>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf8_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf8<char16_t>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 3;
 }
@@ -3721,7 +3721,7 @@ __codecvt_utf8<char32_t>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -3739,7 +3739,7 @@ __codecvt_utf8<char32_t>::do_in(state_type&,
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                            _Maxcode_, _Mode_);
+                            __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -3771,14 +3771,14 @@ __codecvt_utf8<char32_t>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf8_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf8<char32_t>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 7;
     return 4;
 }
@@ -3806,10 +3806,10 @@ __codecvt_utf16<wchar_t, false>::do_out(state_type&,
     uint8_t* _to_nxt = _to;
 #if defined(_LIBCPP_SHORT_WCHAR)
     result r = ucs2_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #else
     result r = ucs4_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3829,13 +3829,13 @@ __codecvt_utf16<wchar_t, false>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf16be_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #else
     uint32_t* _to = reinterpret_cast<uint32_t*>(to);
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf16be_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3869,9 +3869,9 @@ __codecvt_utf16<wchar_t, false>::do_length(state_type&,
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
 #if defined(_LIBCPP_SHORT_WCHAR)
-    return utf16be_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16be_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #else
-    return utf16be_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16be_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #endif
 }
 
@@ -3879,11 +3879,11 @@ int
 __codecvt_utf16<wchar_t, false>::do_max_length() const noexcept
 {
 #if defined(_LIBCPP_SHORT_WCHAR)
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 4;
     return 2;
 #else
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 4;
 #endif
@@ -3910,10 +3910,10 @@ __codecvt_utf16<wchar_t, true>::do_out(state_type&,
     uint8_t* _to_nxt = _to;
 #if defined(_LIBCPP_SHORT_WCHAR)
     result r = ucs2_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #else
     result r = ucs4_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3933,13 +3933,13 @@ __codecvt_utf16<wchar_t, true>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf16le_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #else
     uint32_t* _to = reinterpret_cast<uint32_t*>(to);
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf16le_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
 #endif
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
@@ -3973,9 +3973,9 @@ __codecvt_utf16<wchar_t, true>::do_length(state_type&,
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
 #if defined(_LIBCPP_SHORT_WCHAR)
-    return utf16le_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16le_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #else
-    return utf16le_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16le_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 #endif
 }
 
@@ -3983,11 +3983,11 @@ int
 __codecvt_utf16<wchar_t, true>::do_max_length() const noexcept
 {
 #if defined(_LIBCPP_SHORT_WCHAR)
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 4;
     return 2;
 #else
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 4;
 #endif
@@ -4008,7 +4008,7 @@ __codecvt_utf16<char16_t, false>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs2_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4026,7 +4026,7 @@ __codecvt_utf16<char16_t, false>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf16be_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4058,14 +4058,14 @@ __codecvt_utf16<char16_t, false>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf16be_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16be_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf16<char16_t, false>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 4;
     return 2;
 }
@@ -4085,7 +4085,7 @@ __codecvt_utf16<char16_t, true>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs2_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4103,7 +4103,7 @@ __codecvt_utf16<char16_t, true>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf16le_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4135,14 +4135,14 @@ __codecvt_utf16<char16_t, true>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf16le_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16le_to_ucs2_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf16<char16_t, true>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 4;
     return 2;
 }
@@ -4162,7 +4162,7 @@ __codecvt_utf16<char32_t, false>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs4_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4180,7 +4180,7 @@ __codecvt_utf16<char32_t, false>::do_in(state_type&,
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf16be_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4212,14 +4212,14 @@ __codecvt_utf16<char32_t, false>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf16be_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16be_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf16<char32_t, false>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 4;
 }
@@ -4239,7 +4239,7 @@ __codecvt_utf16<char32_t, true>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = ucs4_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4257,7 +4257,7 @@ __codecvt_utf16<char32_t, true>::do_in(state_type&,
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf16le_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                               _Maxcode_, _Mode_);
+                               __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4289,14 +4289,14 @@ __codecvt_utf16<char32_t, true>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf16le_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf16le_to_ucs4_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf16<char32_t, true>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 6;
     return 4;
 }
@@ -4323,7 +4323,7 @@ __codecvt_utf8_utf16<wchar_t>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4347,7 +4347,7 @@ __codecvt_utf8_utf16<wchar_t>::do_in(state_type&,
     uint32_t* _to_nxt = _to;
 #endif
     result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4379,13 +4379,13 @@ __codecvt_utf8_utf16<wchar_t>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 int
 __codecvt_utf8_utf16<wchar_t>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 7;
     return 4;
 }
@@ -4405,7 +4405,7 @@ __codecvt_utf8_utf16<char16_t>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4423,7 +4423,7 @@ __codecvt_utf8_utf16<char16_t>::do_in(state_type&,
     uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
     uint16_t* _to_nxt = _to;
     result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4455,14 +4455,14 @@ __codecvt_utf8_utf16<char16_t>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf8_utf16<char16_t>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 7;
     return 4;
 }
@@ -4482,7 +4482,7 @@ __codecvt_utf8_utf16<char32_t>::do_out(state_type&,
     uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
     uint8_t* _to_nxt = _to;
     result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4500,7 +4500,7 @@ __codecvt_utf8_utf16<char32_t>::do_in(state_type&,
     uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
     uint32_t* _to_nxt = _to;
     result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
-                             _Maxcode_, _Mode_);
+                             __maxcode_, __mode_);
     frm_nxt = frm + (_frm_nxt - _frm);
     to_nxt = to + (_to_nxt - _to);
     return r;
@@ -4532,14 +4532,14 @@ __codecvt_utf8_utf16<char32_t>::do_length(state_type&,
 {
     const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
     const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
-    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, __maxcode_, __mode_);
 }
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 int
 __codecvt_utf8_utf16<char32_t>::do_max_length() const noexcept
 {
-    if (_Mode_ & consume_header)
+    if (__mode_ & consume_header)
         return 7;
     return 4;
 }

diff  --git a/libcxx/src/memory.cpp b/libcxx/src/memory.cpp
index bf96efa9ce6d4..2dcbb3582a850 100644
--- a/libcxx/src/memory.cpp
+++ b/libcxx/src/memory.cpp
@@ -152,21 +152,21 @@ static constinit __libcpp_mutex_t mut_back[__sp_mut_count] =
 };
 
 _LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) noexcept
-   : __lx(p)
+   : __lx_(p)
 {
 }
 
 void
 __sp_mut::lock() noexcept
 {
-    auto m = static_cast<__libcpp_mutex_t*>(__lx);
+    auto m = static_cast<__libcpp_mutex_t*>(__lx_);
     __libcpp_mutex_lock(m);
 }
 
 void
 __sp_mut::unlock() noexcept
 {
-    __libcpp_mutex_unlock(static_cast<__libcpp_mutex_t*>(__lx));
+    __libcpp_mutex_unlock(static_cast<__libcpp_mutex_t*>(__lx_));
 }
 
 __sp_mut&

diff  --git a/libcxx/src/shared_mutex.cpp b/libcxx/src/shared_mutex.cpp
index deb3ced014cad..73d4dc1c1c7a9 100644
--- a/libcxx/src/shared_mutex.cpp
+++ b/libcxx/src/shared_mutex.cpp
@@ -106,13 +106,13 @@ __shared_mutex_base::unlock_shared()
 
 // Shared Timed Mutex
 // These routines are here for ABI stability
-shared_timed_mutex::shared_timed_mutex() : __base() {}
-void shared_timed_mutex::lock()     { return __base.lock(); }
-bool shared_timed_mutex::try_lock() { return __base.try_lock(); }
-void shared_timed_mutex::unlock()   { return __base.unlock(); }
-void shared_timed_mutex::lock_shared() { return __base.lock_shared(); }
-bool shared_timed_mutex::try_lock_shared() { return __base.try_lock_shared(); }
-void shared_timed_mutex::unlock_shared() { return __base.unlock_shared(); }
+shared_timed_mutex::shared_timed_mutex() : __base_() {}
+void shared_timed_mutex::lock()     { return __base_.lock(); }
+bool shared_timed_mutex::try_lock() { return __base_.try_lock(); }
+void shared_timed_mutex::unlock()   { return __base_.unlock(); }
+void shared_timed_mutex::lock_shared() { return __base_.lock_shared(); }
+bool shared_timed_mutex::try_lock_shared() { return __base_.try_lock_shared(); }
+void shared_timed_mutex::unlock_shared() { return __base_.unlock_shared(); }
 
 _LIBCPP_END_NAMESPACE_STD
 


        


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