Export of internal Abseil changes

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e2a571b818faaec4185426a8cf71fd2970674423 by Matt Kulukundis <kfm@google.com>:

Fix missed use of old RTTI macro

PiperOrigin-RevId: 413239579

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e3c15a3fe0a4e44d6e08d69ad912b2245a403bd6 by Derek Mauro <dmauro@google.com>:

Makes erase_if return the number of erased elements for compatibility
with C++20

https://en.cppreference.com/w/cpp/container/unordered_map/erase_if

This may technically be an API break, but no actual breaks were found
in Google code. Fixes to open source code should be trivial.

Closes #1065

PiperOrigin-RevId: 413204392

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c1fb1ddbc2def3f3d177e5b80b9934bdbb7b16fc by Matt Kulukundis <kfm@google.com>:

Consolidate to a single HAS_RTTI macro

PiperOrigin-RevId: 413169336
GitOrigin-RevId: e2a571b818faaec4185426a8cf71fd2970674423
Change-Id: I74b78ebd5fc172e3f5fcbd13a58cf53f7b250ae9

1 files changed, 10 insertions, 2 deletions

diff --git a/absl/container/btree_set.h b/absl/container/btree_set.h
index 8c96e0ed..2c217d8f 100644
--- a/absl/container/btree_set.h
+++ b/absl/container/btree_set.h
@@ -398,8 +398,11 @@ void swap(btree_set<K, C, A> &x, btree_set<K, C, A> &y) {
 // absl::erase_if(absl::btree_set<>, Pred)
 //
 // Erases all elements that satisfy the predicate pred from the container.
+// Returns the number of erased elements.
 template <typename K, typename C, typename A, typename Pred>
-void erase_if(btree_set<K, C, A> &set, Pred pred) {
+typename btree_set<K, C, A>::size_type erase_if(btree_set<K, C, A> &set,
+                                                Pred pred) {
+  const auto initial_size = set.size();
   for (auto it = set.begin(); it != set.end();) {
     if (pred(*it)) {
       it = set.erase(it);
@@ -407,6 +410,7 @@ void erase_if(btree_set<K, C, A> &set, Pred pred) {
       ++it;
     }
   }
+  return initial_size - set.size();
 }
 
 // absl::btree_multiset<>
@@ -724,8 +728,11 @@ void swap(btree_multiset<K, C, A> &x, btree_multiset<K, C, A> &y) {
 // absl::erase_if(absl::btree_multiset<>, Pred)
 //
 // Erases all elements that satisfy the predicate pred from the container.
+// Returns the number of erased elements.
 template <typename K, typename C, typename A, typename Pred>
-void erase_if(btree_multiset<K, C, A> &set, Pred pred) {
+typename btree_multiset<K, C, A>::size_type erase_if(
+   btree_multiset<K, C, A> & set, Pred pred) {
+  const auto initial_size = set.size();
   for (auto it = set.begin(); it != set.end();) {
     if (pred(*it)) {
       it = set.erase(it);
@@ -733,6 +740,7 @@ void erase_if(btree_multiset<K, C, A> &set, Pred pred) {
       ++it;
     }
   }
+  return initial_size - set.size();
 }
 
 namespace container_internal {