[clang] [Clang][Sema] set declaration invalid earlier to prevent crash in calculating record layout (PR #87173)

[Erich Keane via cfe-commits]

================
@@ -3899,6 +3899,9 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
       SemaRef.Diag(OwnedTagDecl->getLocation(), DiagID)
           << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
       D.setInvalidType(true);
+      OwnedTagDecl->setCompleteDefinition(false);
+      OwnedTagDecl->setInvalidDecl();
+      OwnedTagDecl->setCompleteDefinition();
----------------
erichkeane wrote:

Are we sure the `OwnedTagDecl` is ALWAYS a complete definition here?  Should we cache the existing value before 3902 and restore that rather than always setting it complete?


https://github.com/llvm/llvm-project/pull/87173