UnaryOperator(&)'s creation might need layout of some records
whose fields importation are still on fly, the layout is incorrectly
computed and cached. Clients relying on this will not work properly
or crash direclty (e.g StaticAnalyzer's MemRegion.cpp (calculateOffset)).
Use UnaryOperator::CreateEmpty() instead of UnaryOperator::Create()
to avoid this computation.
Rather than make this a public API, would it instead make sense to add friend class ASTNodeImporter; at the end of the class?