Changes imported from Abseil "staging" branch:

- 14488f5397315b265d57b50e6796890107e0efb2 Clarify comment on absl::NormalizeLogSeverity. by Abseil Team <absl-team@google.com>
  - 401dcf3fdb121e8356e8f54c9f2838faad9ffdf7 Internal change. by Alex Strelnikov <strel@google.com>
  - 1401400b77f8cb5d11fac414c89ffc3b55713f41 Remove unnecessary extern specifier on function declarati... by Alex Strelnikov <strel@google.com>
  - 97d1079d0e8930b1d77bda7bac5e4d15e0e74278 Add missing explicit casts between signed and unsigned in... by Alex Strelnikov <strel@google.com>
  - 47c4138142900de510e4c5426b4bf606252d7dac Internal change. by Alex Strelnikov <strel@google.com>
  - 40eb2555499a000adb78a6581215c701fa818568 Documentation fixes for `absl::optional`, for the `value_... by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 14488f5397315b265d57b50e6796890107e0efb2
Change-Id: I3c11216c0c6ef5633aa5cc3b7f5977fa4a3ea1f5

absl/base/log_severity.h

@@ -46,7 +46,7 @@ constexpr const char* LogSeverityName(absl::LogSeverity s) {
                          : s == absl::LogSeverity::kFatal ? "FATAL" : "UNKNOWN";
 }
 
-// Note that out-of-range large severities normalize to kError, not kFatal.
+// Note that out-of-range severities normalize to kInfo or kError, never kFatal.
 constexpr absl::LogSeverity NormalizeLogSeverity(absl::LogSeverity s) {
   return s < absl::LogSeverity::kInfo
              ? absl::LogSeverity::kInfo

absl/numeric/int128.h

@@ -206,7 +206,7 @@ class alignas(16) uint128 {
 extern const uint128 kuint128max;
 
 // allow uint128 to be logged
-extern std::ostream& operator<<(std::ostream& os, uint128 v);
+std::ostream& operator<<(std::ostream& os, uint128 v);
 
 // TODO(strel) add operator>>(std::istream&, uint128)
 
@@ -287,55 +287,61 @@ constexpr uint64_t Uint128High64(uint128 v) { return v.hi_; }
 #if defined(ABSL_IS_LITTLE_ENDIAN)
 
 constexpr uint128::uint128(uint64_t high, uint64_t low)
-    : lo_(low), hi_(high) {}
+    : lo_{low}, hi_{high} {}
 
 constexpr uint128::uint128(int v)
-    : lo_(v), hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0) {}
+    : lo_{static_cast<uint64_t>(v)},
+      hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0} {}
 constexpr uint128::uint128(long v)  // NOLINT(runtime/int)
-    : lo_(v), hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0) {}
+    : lo_{static_cast<uint64_t>(v)},
+      hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0} {}
 constexpr uint128::uint128(long long v)  // NOLINT(runtime/int)
-    : lo_(v), hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0) {}
+    : lo_{static_cast<uint64_t>(v)},
+      hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0} {}
 
-constexpr uint128::uint128(unsigned int v) : lo_(v), hi_(0) {}
+constexpr uint128::uint128(unsigned int v) : lo_{v}, hi_{0} {}
 // NOLINTNEXTLINE(runtime/int)
-constexpr uint128::uint128(unsigned long v) : lo_(v), hi_(0) {}
+constexpr uint128::uint128(unsigned long v) : lo_{v}, hi_{0} {}
 // NOLINTNEXTLINE(runtime/int)
-constexpr uint128::uint128(unsigned long long v) : lo_(v), hi_(0) {}
+constexpr uint128::uint128(unsigned long long v) : lo_{v}, hi_{0} {}
 
 #ifdef ABSL_HAVE_INTRINSIC_INT128
 constexpr uint128::uint128(__int128 v)
-    : lo_(static_cast<uint64_t>(v & ~uint64_t{0})),
-      hi_(static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)) {}
+    : lo_{static_cast<uint64_t>(v & ~uint64_t{0})},
+      hi_{static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)} {}
 constexpr uint128::uint128(unsigned __int128 v)
-    : lo_(static_cast<uint64_t>(v & ~uint64_t{0})),
-      hi_(static_cast<uint64_t>(v >> 64)) {}
+    : lo_{static_cast<uint64_t>(v & ~uint64_t{0})},
+      hi_{static_cast<uint64_t>(v >> 64)} {}
 #endif  // ABSL_HAVE_INTRINSIC_INT128
 
 #elif defined(ABSL_IS_BIG_ENDIAN)
 
 constexpr uint128::uint128(uint64_t high, uint64_t low)
-    : hi_(high), lo_(low) {}
+    : hi_{high}, lo_{low} {}
 
 constexpr uint128::uint128(int v)
-    : hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0), lo_(v) {}
+    : hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0},
+      lo_{static_cast<uint64_t>(v)} {}
 constexpr uint128::uint128(long v)  // NOLINT(runtime/int)
-    : hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0), lo_(v) {}
+    : hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0},
+      lo_{static_cast<uint64_t>(v)} {}
 constexpr uint128::uint128(long long v)  // NOLINT(runtime/int)
-    : hi_(v < 0 ? std::numeric_limits<uint64_t>::max() : 0), lo_(v) {}
+    : hi_{v < 0 ? std::numeric_limits<uint64_t>::max() : 0},
+      lo_{static_cast<uint64_t>(v)} {}
 
-constexpr uint128::uint128(unsigned int v) : hi_(0), lo_(v) {}
+constexpr uint128::uint128(unsigned int v) : hi_{0}, lo_{v} {}
 // NOLINTNEXTLINE(runtime/int)
-constexpr uint128::uint128(unsigned long v) : hi_(0), lo_(v) {}
+constexpr uint128::uint128(unsigned long v) : hi_{0}, lo_{v} {}
 // NOLINTNEXTLINE(runtime/int)
-constexpr uint128::uint128(unsigned long long v) : hi_(0), lo_(v) {}
+constexpr uint128::uint128(unsigned long long v) : hi_{0}, lo_{v} {}
 
 #ifdef ABSL_HAVE_INTRINSIC_INT128
 constexpr uint128::uint128(__int128 v)
-    : hi_(static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)),
-      lo_(static_cast<uint64_t>(v & ~uint64_t{0})) {}
+    : hi_{static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)},
+      lo_{static_cast<uint64_t>(v & ~uint64_t{0})} {}
 constexpr uint128::uint128(unsigned __int128 v)
-    : hi_(static_cast<uint64_t>(v >> 64)),
-      lo_(static_cast<uint64_t>(v & ~uint64_t{0})) {}
+    : hi_{static_cast<uint64_t>(v >> 64)},
+      lo_{static_cast<uint64_t>(v & ~uint64_t{0})} {}
 #endif  // ABSL_HAVE_INTRINSIC_INT128
 
 #else  // byte order

absl/types/optional.h

@@ -845,7 +845,7 @@ class optional : private optional_internal::optional_data<T>,
 
   // optional::value_or()
   //
-  // Returns either the value of `T` or a passed default `val` if the `optional`
+  // Returns either the value of `T` or a passed default `v` if the `optional`
   // is empty.
   template <typename U>
   constexpr T value_or(U&& v) const& {