fn main() {
    // Set float and int, m and b, respectively.
    let (fm, fb) = (3.0, 2.0);
    let (im, ib) = (3, 2);

    // Two closures each using floats and ints
    let float_line = move |x| fm * x + fb;
    let int_line = |x| im * x + ib;

    // Interesting bit. The slope_function doesn't set
    // type inference to float, once the 'I' type is used.
    let i_line = slope_function(int_line, 2);
    let f_line = slope_function(float_line, 2.0);

    println!("Hello, world! {:?} {:?} {:?}", float_line(2.0), i_line, f_line);

}

// Closure function taking a closure, and int as input.
fn slope_function<I>(f: impl Fn(I) -> I, x: I) -> I {
    f(x)
}