//@ run-pass struct StrWrap { s: String } impl StrWrap { fn new(s: &str) -> StrWrap { StrWrap { s: s.to_string() } } fn get_s<'a>(&'a self) -> &'a str { &self.s } } struct MyStruct { s: StrWrap } impl MyStruct { fn new(s: &str) -> MyStruct { MyStruct { s: StrWrap::new(s) } } fn get_str_wrap<'a>(&'a self) -> &'a StrWrap { &self.s } } trait Matcher { fn matches(&self, actual: T) -> bool; } fn assert_that>(actual: T, matcher: &U) { assert!(matcher.matches(actual)); } struct EqualTo { expected: T } impl Matcher for EqualTo { fn matches(&self, actual: T) -> bool { self.expected.eq(&actual) } } fn equal_to(expected: T) -> Box> { Box::new(EqualTo { expected: expected }) } pub fn main() { let my_struct = MyStruct::new("zomg"); let s = my_struct.get_str_wrap(); assert_that(s.get_s(), &*equal_to("zomg")); }