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

[Erich Keane via cfe-commits]

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@@ -4561,6 +4569,15 @@ static void TryConstructorInitialization(Sema &S,
 
   CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
   if (Result != OR_Deleted) {
+    if (!IsListInit && Kind.getKind() == InitializationKind::IK_Default &&
+        DestRecordDecl != nullptr && DestRecordDecl->isAggregate() &&
+        DestRecordDecl->hasUninitializedExplicitInitFields()) {
+      S.Diag(Kind.getLocation(), diag::warn_field_requires_explicit_init)
+          << ("in " +
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erichkeane wrote:

"in " should be part of the diagnostic, we shouldn't be calculating strings like this here (as the idea is that some day we should be able to translate the DiagnosticSemaKinds.td file for a translated compiler).

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