// 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. use std::borrow::Cow; pub trait IntoCow<'a, B: ?Sized> where B: ToOwned { fn into_cow(self) -> Cow<'a, B>; } impl<'a> IntoCow<'a, str> for String { fn into_cow(self) -> Cow<'a, str> { Cow::Owned(self) } } fn main() { ::into_cow("foo".to_string()); //~^ ERROR too few type parameters provided: expected 1 parameter }