/// Generic pair.
record Pair⟨T, U⟩ {
    /// First value.
    first: T,
    /// Second value.
    second: U,
}

instantiate Pair⟨i32, bool⟩;

/// Construct a specialized pair.
fn makePair(first: i32, second: bool) -> Pair⟨i32, bool⟩ {
    return Pair⟨i32, bool⟩ { first, second };
}

/// Return the first value of a specialized pair.
fn first(pair: Pair⟨i32, bool⟩) -> i32 {
    return pair.first;
}