Function is_vector_valued 

fn is_vector_valued(ty: &Type) -> bool

Whether an argument of Rust type ty holds several values, so a no_na failure reads must not contain NA rather than must not be NA.

The type table decides when it knows the type (RTypeCheck::is_vector): Vec<T> and slices, the vector markers (AsNumericVec, AsCharacterVec, any marker whose table entry is a vector check), maps and lists. For a type the table does not know, the shape decides: Vec<T>, Box<[T]>, slices and arrays, and a type named ...Vec (the vector half of a marker family such as AsFromStrVec / AsDisplayVec, or a vector type like BitVec).