// Copyright 2014 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. pub fn foo(params: Option<&[&str]>) -> uint { params.unwrap().head().unwrap().len() } fn main() { let name = "Foo"; let msg = foo(Some(&[name.as_slice()])); //~^ ERROR mismatched types: expected `core::option::Option<&[&str]>` assert_eq!(msg, 3); }