[clang] [Clang] Warn when an explicit alignment is weakened by other directives (PR #198417)

[David Meng via cfe-commits]

================
@@ -1210,15 +1217,16 @@ ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
       HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
   }
 
+  // Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
+  // Per GCC's documentation, it only applies to non-static data members.
+  const bool PackedAppliesToBases =
----------------
davidmenggx wrote:

Reused on line 1287

https://github.com/llvm/llvm-project/pull/198417