rustc::lint::builtin::UNSIZED_IN_TUPLE

pub static UNSIZED_IN_TUPLE: &'static Lint = &::rustc::lint::Lint{name: "UNSIZED_IN_TUPLE",
                     default_level: ::rustc::lint::Warn,
                     desc:
                         "unsized types in the interior of a tuple were erroneously allowed",}

Unstable (rustc_private)