Function __action15

fn __action15(
    cx: &mut ParseCtxt<'_>,
    (_, name, _): (Location, Ident, Location),
    (_, _, _): (Location, Token, Location),
    (_, lo, _): (Location, Location, Location),
    (_, kind, _): (Location, Ident, Location),
    (_, hi, _): (Location, Location, Location),
) -> Result<GenericParam, ParseError<Location, Token, UserParseError>>