# Trait Alias Thin

Source

    trait Thin = Pointee<Metadata = ()>;

🔬This is a nightly-only experimental API. (`ptr_metadata` #81513)
Expand description

Pointers to types implementing this trait alias are “thin”.

This includes statically-`Sized` types and `extern` types.

## §Example

    #![feature(ptr_metadata)]

    fn this_never_panics<T: std::ptr::Thin>() {
        assert_eq!(size_of::<&T>(), size_of::<usize>())
    }