[clang] Add Clang attribute to ensure that fields are initialized explicitly (PR #102040)

[Erich Keane via cfe-commits]

================
@@ -4561,6 +4569,13 @@ static void TryConstructorInitialization(Sema &S,
 
   CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
   if (Result != OR_Deleted) {
+    if (!IsListInit && Kind.getKind() == InitializationKind::IK_Default &&
----------------
erichkeane wrote:

You're just checking that it isnt list-init, but it could be copy/normal constructor init, right?  if you mean to catch 'default' initialization, don't you have to check the 'IK_Default' like on 4588?

https://github.com/llvm/llvm-project/pull/102040