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use std::fmt;
use std::ops::Deref;

#[derive(Copy, Clone, Default, Eq, Hash, PartialEq, PartialOrd, Ord, Debug)]
pub struct Frozen<T> {
    val: T,
}

impl<T> Frozen<T> {
    pub fn freeze(val: T) -> Frozen<T> {
        Frozen { val: val }
    }

    pub fn thaw(self) -> T {
        self.val
    }
}

impl<T> Deref for Frozen<T> {
    type Target = T;
    fn deref(&self) -> &T {
        &self.val
    }
}

impl<U, T> AsRef<U> for Frozen<T> where T: AsRef<U> {
    fn as_ref(&self) -> &U {
        self.val.as_ref()
    }
}

impl<T: fmt::Display> fmt::Display for Frozen<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        self.val.fmt(f)
    }
}