test.rs

// Using Rust 0.9:

#[feature(struct_variant)];

enum X {
	Y { y: ~str }
}

impl X {
	fn foo(&self) {
		match self {
			&Y { y } => println!("y = {}", y)
		}
	}
}

fn main() {
	let s = ~"abc";
	let x = Y { y: s };
	x.foo();
	x.foo();
}

// $ rustc test.rs && ./test
// test.rs:11:5: 11:12 error: cannot move out of dereference of & pointer
// test.rs:11 			&Y { y } => println!("y = {}", y)
//            			 ^~~~~~~
// error: aborting due to previous error
// task 'rustc' failed at 'explicit failure', /private/tmp/rust-R5p2/rust-0.9/src/libsyntax/diagnostic.rs:75
// task '<main>' failed at 'explicit failure', /private/tmp/rust-R5p2/rust-0.9/src/librustc/lib.rs:453
// $ 

try &Y { ref y } instead of &Y { y } in your pattern, to indicate that you want to bind y as a reference into whatever self is pointing to, rather than attempting to move those contents out of whatever self points to (which you are not allowed to do).

Yeah, that was the problem. I think the tutorial was a bit unclear about that part, as I tried both ~ref and &ref before finding a similar question on stackoverflow.