// Copyright 2016 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. #![feature(specialization)] trait Foo: Copy + ToString {} impl Foo for T {} fn hide(x: T) -> impl Foo { x } fn two(x: bool) -> impl Foo { if x { return 1_i32; } 0_u32 //~^ ERROR mismatched types //~| expected i32, found u32 } fn sum_to(n: u32) -> impl Foo { if n == 0 { 0 } else { n + sum_to(n - 1) //~^ ERROR cannot add `impl Foo` to `u32` } } trait Leak: Sized { type T; fn leak(self) -> Self::T; } impl Leak for T { default type T = (); default fn leak(self) -> Self::T { panic!() } } impl Leak for i32 { type T = i32; fn leak(self) -> i32 { self } } fn main() { }