pub type ExecScanRecheckMtd = Option<unsafe extern "C" fn(node: *mut ScanState, slot: *mut TupleTableSlot) -> bool>;
pub enum ExecScanRecheckMtd { None, Some(unsafe extern "C" fn(*mut ScanState, *mut TupleTableSlot) -> bool), }
No value.
Some value of type T.
T