# `attr_literals`

The tracking issue for this feature is: #34981

At present, literals are only accepted as the value of a key-value pair in attributes. What's more, only string literals are accepted. This means that literals can only appear in forms of `#[attr(name = "value")]` or `#[attr = "value"]`.

The `attr_literals` unstable feature allows other types of literals to be used in attributes. Here are some examples of attributes that can now be used with this feature enabled:

    #[attr]
    #[attr(true)]
    #[attr(ident)]
    #[attr(ident, 100, true, "true", ident = 100, ident = "hello", ident(100))]
    #[attr(100)]
    #[attr(enabled = true)]
    #[enabled(true)]
    #[attr("hello")]
    #[repr(C, align = 4)]
    #[repr(C, align(4))]