// Copyright 2012-2018 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. // compile-pass #![feature(const_let)] #![feature(underscore_const_names)] trait Trt {} struct Str {} impl Trt for Str {} macro_rules! check_impl { ($struct:ident,$trait:ident) => { const _ : () = { use std::marker::PhantomData; struct ImplementsTrait(PhantomData); let _ = ImplementsTrait::<$struct>(PhantomData); () }; } } #[deny(unused)] const _ : () = (); const _ : i32 = 42; const _ : Str = Str{}; check_impl!(Str, Trt); check_impl!(Str, Trt); fn main() { check_impl!(Str, Trt); check_impl!(Str, Trt); }