fn with<T>(t: T, f: fn(T)) { f(t) }

fn nested(x: &x/int) {  // (1)
    do with(
        fn&(x: &x/int, // Refers to the region `x` at (1)
            y: &y/int, // A fresh region `y` (2)
            z: fn(x: &x/int, // Refers to `x` at (1)
                  y: &y/int, // Refers to `y` at (2)
                  z: &z/int) -> &z/int) // A fresh region `z` (3)
            -> &x/int {

            if false { ret z(x, x, x); } //~ ERROR mismatched types: expected `&y/int` but found `&x/int`
            if false { ret z(x, x, y); } //~ ERROR mismatched types: expected `&y/int` but found `&x/int`
                                        //~^ ERROR mismatched types: expected `&x/int` but found `&y/int`
            if false { ret z(x, y, x); }
            if false { ret z(x, y, y); } //~ ERROR mismatched types: expected `&x/int` but found `&y/int`
            if false { ret z(y, x, x); } //~ ERROR mismatched types: expected `&x/int` but found `&y/int`
                                        //~^ ERROR mismatched types: expected `&y/int` but found `&x/int`
            if false { ret z(y, x, y); } //~ ERROR mismatched types: expected `&x/int` but found `&y/int`
                                        //~^ ERROR mismatched types: expected `&y/int` but found `&x/int`
                                       //~^^ ERROR mismatched types: expected `&x/int` but found `&y/int`
            if false { ret z(y, y, x); } //~ ERROR mismatched types: expected `&x/int` but found `&y/int`
            if false { ret z(y, y, y); } //~ ERROR mismatched types: expected `&x/int` but found `&y/int`
                                        //~^ ERROR mismatched types: expected `&x/int` but found `&y/int`
            fail;
        }
    ) |foo| {

        let a: &x/int = foo(x, x, |_x, _y, z| z );
        let b: &x/int = foo(x, a, |_x, _y, z| z );
        let c: &x/int = foo(a, a, |_x, _y, z| z );

        let z = 3i;
        let d: &x/int = foo(x, x, |_x, _y, z| z );
        let e: &x/int = foo(x, &z, |_x, _y, z| z );
        let f: &x/int = foo(&z, &z, |_x, _y, z| z ); //~ ERROR mismatched types: expected `&x/int` but found

        foo(x, &z, |x, _y, _z| x ); //~ ERROR mismatched types: expected `&z/int` but found `&x/int`
        foo(x, &z, |_x, y, _z| y ); //~ ERROR mismatched types: expected `&z/int` but found `&<block at
    }
}

fn main() {}