Export of internal Abseil changes

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0f6565955231dc74ebad62ef32a18c457afa2dc7 by Abseil Team <absl-team@google.com>:

Document guarantee that we do not move from rvalue arguments if no insertion happens with absl::raw_hash_map::try_emplace, as done with std::unordered_map::try_emplace.

PiperOrigin-RevId: 264430409

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292e6b9e08fa689e8400d7f2db94cbcab29d5889 by CJ Johnson <johnsoncj@google.com>:

Removes use of aligned_storage in FixedArray and InlinedVector in favor of aligned char buffers.

PiperOrigin-RevId: 264385559

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aa0b19ad11ae5702022feee0e2e6434cfb28c9e9 by Derek Mauro <dmauro@google.com>:

Make the unit tests for absl::any, absl::optional, and absl::variant
no-ops when these types are just aliases for the corresponding std::
types. We have no way to fix standard library implementation bugs, so
don't bother working around them.

Also disable the corresponding exception-safety tests as well when
exceptions are not enabled.

Fixes https://github.com/abseil/abseil-cpp/pull/360

PiperOrigin-RevId: 264382050

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65896a911f36481b89b4712c83b91c90a76b64e8 by Abseil Team <absl-team@google.com>:

Improve documentation on erase

PiperOrigin-RevId: 264381266
GitOrigin-RevId: 0f6565955231dc74ebad62ef32a18c457afa2dc7
Change-Id: I74b9bd2ddf84526014104f17e87de70bd3fe65fa

1 files changed, 11 insertions, 17 deletions

diff --git a/absl/container/fixed_array.h b/absl/container/fixed_array.h
index 2a8240a..70e94ad 100644
--- a/absl/container/fixed_array.h
+++ b/absl/container/fixed_array.h
@@ -31,7 +31,6 @@
 #define ABSL_CONTAINER_FIXED_ARRAY_H_
 
 #include <algorithm>
-#include <array>
 #include <cassert>
 #include <cstddef>
 #include <initializer_list>
@@ -386,8 +385,7 @@ class FixedArray {
   //     error: call to int __builtin___sprintf_chk(etc...)
   //     will always overflow destination buffer [-Werror]
   //
-  template <typename OuterT = value_type,
-            typename InnerT = absl::remove_extent_t<OuterT>,
+  template <typename OuterT, typename InnerT = absl::remove_extent_t<OuterT>,
             size_t InnerN = std::extent<OuterT>::value>
   struct StorageElementWrapper {
     InnerT array[InnerN];
@@ -396,8 +394,6 @@ class FixedArray {
   using StorageElement =
       absl::conditional_t<std::is_array<value_type>::value,
                           StorageElementWrapper<value_type>, value_type>;
-  using StorageElementBuffer =
-      absl::aligned_storage_t<sizeof(StorageElement), alignof(StorageElement)>;
 
   static pointer AsValueType(pointer ptr) { return ptr; }
   static pointer AsValueType(StorageElementWrapper<value_type>* ptr) {
@@ -407,25 +403,25 @@ class FixedArray {
   static_assert(sizeof(StorageElement) == sizeof(value_type), "");
   static_assert(alignof(StorageElement) == alignof(value_type), "");
 
-  struct NonEmptyInlinedStorage {
-    StorageElement* data() {
-      return reinterpret_cast<StorageElement*>(inlined_storage_.data());
-    }
+  class NonEmptyInlinedStorage {
+   public:
+    StorageElement* data() { return reinterpret_cast<StorageElement*>(buff_); }
+    void AnnotateConstruct(size_type n);
+    void AnnotateDestruct(size_type n);
 
 #ifdef ADDRESS_SANITIZER
     void* RedzoneBegin() { return &redzone_begin_; }
     void* RedzoneEnd() { return &redzone_end_ + 1; }
 #endif  // ADDRESS_SANITIZER
 
-    void AnnotateConstruct(size_type);
-    void AnnotateDestruct(size_type);
-
+   private:
     ADDRESS_SANITIZER_REDZONE(redzone_begin_);
-    std::array<StorageElementBuffer, inline_elements> inlined_storage_;
+    alignas(StorageElement) char buff_[sizeof(StorageElement[inline_elements])];
     ADDRESS_SANITIZER_REDZONE(redzone_end_);
   };
 
-  struct EmptyInlinedStorage {
+  class EmptyInlinedStorage {
+   public:
     StorageElement* data() { return nullptr; }
     void AnnotateConstruct(size_type) {}
     void AnnotateDestruct(size_type) {}
@@ -459,9 +455,7 @@ class FixedArray {
     size_type size() const { return size_alloc_.template get<0>(); }
     StorageElement* begin() const { return data_; }
     StorageElement* end() const { return begin() + size(); }
-    allocator_type& alloc() {
-      return size_alloc_.template get<1>();
-    }
+    allocator_type& alloc() { return size_alloc_.template get<1>(); }
 
    private:
     static bool UsingInlinedStorage(size_type n) {