If in core I would still want to expose this as say a contrib module binary instead of hacking it into postgres. It would be our first server program entry there.
Sorry for self-reply but:
Maybe name it "pg_script_check" with a, for now mandatory, "--syntax-only" option that enables this raw parse mode. Leaving room for executing this in an environment where there is, or it can launch, a running instance that then performs post-parse analysis as well.
