pub fn optional(&self) -> Self {
        Type {
            kind: self.kind.clone(),
            optional: true,
        }
    }
/// Return an optional version of this type reference.
/// Returns an identical copy if the type is already optional.
Return an optional version of this type reference.
Returns an identical copy if the type is already optional.
Return an optional version of this type reference . Returns an identical copy if the type is already optional .
pub fn optional(&self) -> Self {
        Type {
            kind: self.kind.clone(),
            optional: true,
        }
    }
pub fn optional ( & self ) -> Self { Type { kind : self . kind . clone ( ) , optional : true , } }
Return an optional version of this type reference.
Return an optional version of this type reference .
&self
&self