From 61b059f79e8c2acf1f9bd0d48b07cbff9d7e5a06 Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Wed, 29 Mar 2023 17:35:26 -0700
Subject: inlined_vector: fix incorrect conditions for move constructor fast
 paths.

These have nothing to do with copy construction or copy assignment, and using
"is trivially copy constructible" can in theory even give the wrong result if
the copy constructor is trivial but the move constructor is not.

PiperOrigin-RevId: 520488816
Change-Id: I6da4d57f3ce23b03044e0bf9aa70a14b51651fa3
---
 absl/container/internal/inlined_vector.h | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

(limited to 'absl/container/internal/inlined_vector.h')

diff --git a/absl/container/internal/inlined_vector.h b/absl/container/internal/inlined_vector.h
index 6397db48..4e628424 100644
--- a/absl/container/internal/inlined_vector.h
+++ b/absl/container/internal/inlined_vector.h
@@ -510,16 +510,20 @@ class Storage {
     //
     //  *  It's possible to trivially copy construct/assign the elements.
     //
-    // TODO(b/274984172): the conditions here, preserved from historical ones,
-    // don't actually implement this. They are far too conservative (they don't
-    // work for move-only types, and require both copyability and
-    // assignability).
-    ABSL_HARDENING_ASSERT(
-        other_storage.GetIsAllocated() ||
-        (std::is_same<A, std::allocator<ValueType<A>>>::value &&
-         absl::is_trivially_copy_constructible<ValueType<A>>::value &&
-         absl::is_trivially_copy_assignable<ValueType<A>>::value &&
-         absl::is_trivially_destructible<ValueType<A>>::value));
+    {
+      using V = ValueType<A>;
+      ABSL_HARDENING_ASSERT(
+          other_storage.GetIsAllocated() ||
+          (std::is_same<A, std::allocator<V>>::value &&
+           (
+               // First case above
+               ((absl::is_trivially_move_constructible<V>::value ||
+                 absl::is_trivially_move_assignable<V>::value) &&
+                absl::is_trivially_destructible<V>::value) ||
+               // Second case above
+               (absl::is_trivially_copy_constructible<V>::value ||
+                absl::is_trivially_copy_assignable<V>::value))));
+    }
 
     GetSizeAndIsAllocated() = other_storage.GetSizeAndIsAllocated();
     data_ = other_storage.data_;
-- 
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