rustc::lint::builtin::OBJECT_UNSAFE_FRAGMENT

pub static OBJECT_UNSAFE_FRAGMENT: &'static Lint = &::rustc::lint::Lint{name: "OBJECT_UNSAFE_FRAGMENT",
                     default_level: ::rustc::lint::Warn,
                     desc:
                         "object-unsafe non-principal fragments in object types were erroneously allowed",}

Unstable (rustc_private)