Add moved-from validation for the case of self-move-assignment.

PiperOrigin-RevId: 669363872
Change-Id: I2aeac23eb082a7bdabe65b3f55fd8adea6930386

absl/container/internal/raw_hash_set.h

diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index c371832..f5463fb 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -3777,7 +3777,7 @@
     // We only enable moved-from validation when generations are enabled (rather
     // than using NDEBUG) to avoid issues in which NDEBUG is enabled in some
     // translation units but not in others.
-    if (SwisstableGenerationsEnabled() && this != &that) {
+    if (SwisstableGenerationsEnabled()) {
       that.common().set_capacity(InvalidCapacity::kMovedFrom);
     }
     if (!SwisstableGenerationsEnabled() || capacity() == DefaultCapacity() ||

absl/container/internal/raw_hash_set_test.cc

diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index 3d5f59a..f69fca3 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -2091,6 +2091,10 @@
   t.emplace("a", "b");
   EXPECT_EQ(1, t.size());
   t = std::move(*&t);
+  if (SwisstableGenerationsEnabled()) {
+    // NOLINTNEXTLINE(bugprone-use-after-move)
+    EXPECT_DEATH_IF_SUPPORTED(t.contains("a"), "");
+  }
   // As long as we don't crash, it's fine.
 }