Function parse_lo_file_call 

pub fn parse_lo_file_call(sql: &str) -> Option<LoFileCall>

Recognise a bare SELECT lo_import(…) / SELECT lo_export(…).

Deliberately narrow: only the statement-level spelling is intercepted, which is the one that reaches a file. Anything else — the call nested in a larger expression — is left to the ordinary evaluator, which reports it as unsupported rather than silently doing nothing.