Method mutate

aiscript-arena/src/arena.rs:214–223

(&self, f: F)

    /// but no garbage collection will take place during this method.
    #[inline]
    pub fn mutate<F, T>(&self, f: F) -> T
    where
        F: for<'gc> FnOnce(&'gc Mutation<'gc>, &'gc Root<'gc, R>) -> T,
    {
        unsafe {
            let mc: &'static Mutation<'_> = &*(self.context.mutation_context() as *const _);
            let root: &'static Root<'_, R> = &*(&self.root as *const _);
            f(mc, root)
        }
    }

    /// An alternative version of [`Arena::mutate`] which allows mutating the root set, at the
    /// cost of an extra write barrier.