Export of internal Abseil changes

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336f161ad8cb2cc3e1a6bbcbbb8c5b692ee59789 by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 398308807

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80d512823d17561a45feca81f37713a91a175349 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 398257218

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f1f9792000355eb1d0c11b17800048491662a218 by Abseil Team <absl-team@google.com>:

Fix documentation for btree_multi{map,set}::merge to match behavior for elements with equivalent keys.

PiperOrigin-RevId: 398071060

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8a9a302aebf2419e83f0c7dc5a63c33d26b807a3 by James Y Knight <jyknight@google.com>:

Silence -Wunused-value warning newly emitted by ToT Clang.

The value is being intentionally ignored, as the purpose of the call is only to eliminate this overload via SFINAE when `GenT{}` is not constant evaluable.

PiperOrigin-RevId: 397861294
GitOrigin-RevId: 336f161ad8cb2cc3e1a6bbcbbb8c5b692ee59789
Change-Id: I946e1d22619f92ce6a424c8c13a20a50b39ed463

absl/container/btree_map.h

@@ -693,9 +693,8 @@ class btree_multimap
 
   // btree_multimap::merge()
   //
-  // Extracts elements from a given `source` btree_multimap into this
-  // `btree_multimap`. If the destination `btree_multimap` already contains an
-  // element with an equivalent key, that element is not extracted.
+  // Extracts all elements from a given `source` btree_multimap into this
+  // `btree_multimap`.
   using Base::merge;
 
   // btree_multimap::swap(btree_multimap& other)

absl/container/btree_set.h

@@ -604,9 +604,8 @@ class btree_multiset
 
   // btree_multiset::merge()
   //
-  // Extracts elements from a given `source` btree_multiset into this
-  // `btree_multiset`. If the destination `btree_multiset` already contains an
-  // element with an equivalent key, that element is not extracted.
+  // Extracts all elements from a given `source` btree_multiset into this
+  // `btree_multiset`.
   using Base::merge;
 
   // btree_multiset::swap(btree_multiset& other)

absl/container/inlined_vector.h

@@ -207,8 +207,8 @@ class InlinedVector {
 
       other.storage_.SetInlinedSize(0);
     } else if (other.storage_.GetIsAllocated()) {
-      storage_.SetAllocatedData(other.storage_.GetAllocatedData(),
-                                other.storage_.GetAllocatedCapacity());
+      storage_.SetAllocation({other.storage_.GetAllocatedData(),
+                              other.storage_.GetAllocatedCapacity()});
       storage_.SetAllocatedSize(other.storage_.GetSize());
 
       other.storage_.SetInlinedSize(0);
@@ -242,8 +242,8 @@ class InlinedVector {
       other.storage_.SetInlinedSize(0);
     } else if ((storage_.GetAllocator() == other.storage_.GetAllocator()) &&
                other.storage_.GetIsAllocated()) {
-      storage_.SetAllocatedData(other.storage_.GetAllocatedData(),
-                                other.storage_.GetAllocatedCapacity());
+      storage_.SetAllocation({other.storage_.GetAllocatedData(),
+                              other.storage_.GetAllocatedCapacity()});
       storage_.SetAllocatedSize(other.storage_.GetSize());
 
       other.storage_.SetInlinedSize(0);
@@ -735,15 +735,12 @@ class InlinedVector {
 
   // `InlinedVector::shrink_to_fit()`
   //
-  // Reduces memory usage by freeing unused memory. After being called, calls to
-  // `capacity()` will be equal to `max(N, size())`.
+  // Attempts to reduce memory usage by moving elements to (or keeping elements
+  // in) the smallest available buffer sufficient for containing `size()`
+  // elements.
   //
-  // If `size() <= N` and the inlined vector contains allocated memory, the
-  // elements will all be moved to the inlined space and the allocated memory
-  // will be deallocated.
-  //
-  // If `size() > N` and `size() < capacity()`, the elements will be moved to a
-  // smaller allocation.
+  // If `size()` is sufficiently small, the elements will be moved into (or kept
+  // in) the inlined space.
   void shrink_to_fit() {
     if (storage_.GetIsAllocated()) {
       storage_.ShrinkToFit();

absl/flags/internal/flag.h

@@ -290,7 +290,7 @@ constexpr T InitDefaultValue(EmptyBraces) {
 
 template <typename ValueT, typename GenT,
           typename std::enable_if<std::is_integral<ValueT>::value, int>::type =
-              (GenT{}, 0)>
+              ((void)GenT{}, 0)>
 constexpr FlagDefaultArg DefaultArg(int) {
   return {FlagDefaultSrc(GenT{}.value), FlagDefaultKind::kOneWord};
 }

absl/meta/type_traits.h

@@ -35,7 +35,7 @@
 #ifndef ABSL_META_TYPE_TRAITS_H_
 #define ABSL_META_TYPE_TRAITS_H_
 
-#include <stddef.h>
+#include <cstddef>
 #include <functional>
 #include <type_traits>
 
@@ -47,6 +47,14 @@
 #define ABSL_META_INTERNAL_STD_CONSTRUCTION_TRAITS_DONT_CHECK_DESTRUCTION 1
 #endif
 
+// Defines the default alignment. `__STDCPP_DEFAULT_NEW_ALIGNMENT__` is a C++17
+// feature.
+#if defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+#define ABSL_INTERNAL_DEFAULT_NEW_ALIGNMENT __STDCPP_DEFAULT_NEW_ALIGNMENT__
+#else  // defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+#define ABSL_INTERNAL_DEFAULT_NEW_ALIGNMENT alignof(std::max_align_t)
+#endif  // defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+
 namespace absl {
 ABSL_NAMESPACE_BEGIN