Change:
Spawned off of There are still some cases where referencing an inaccessible item can cause the compiler to ICE. Here is one crafted example () but if 's module structure is revised then that example may fail to compile without ICE'ing for other reasons, so take care in understanding the issue: the change introduced by is skipping the requirement for stability attributes is slightly too narrow, in that it uses a local notion of pub/non-pub instead of overall accessibility. One simple solution to this may be to just follow the suggestion here and just remove the assertion entirely. (I did not want to adopt that solution for a PR to be backported to beta, but I think it is worth considering doing in nightly alone to resolve this low priority issue.)
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<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. struct Foo; fn main() { || if let Foo::NotEvenReal() = Foo {}; //~ ERROR E0599 } </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. // #29924 #![feature(const_fn, associated_consts)] trait Trait { const N: usize; } impl Trait { //~^ ERROR the trait `Trait` cannot be made into an object [E0038] const fn n() -> usize { Self::N } } fn main() {} </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. // #39872, #39553 #![feature(conservative_impl_trait)] fn will_ice(something: &u32) -> impl Iterator<Item = &u32> { //~^ ERROR the trait bound `(): std::iter::Iterator` is not satisfied [E0277] } fn main() {} </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. fn main() { let a = std::sys::imp::process::process_common::StdioPipes { ..panic!() }; //~^ ERROR failed to resolve. Could not find `imp` in `sys` [E0433] //~^^ ERROR module `sys` is private [E0603] } </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. fn iterate<T, F>(initial: T, f: F) -> Iterate<T, F> { Iterate { state: initial, f: f, } } pub struct Iterate<T, F> { state: T, f: F } impl<T: Clone, F> Iterator for Iterate<T, F> where F: Fn(&T) -> T { type Item = T; #[inline] fn next(&mut self) -> Option<Self::Item> { self.state = (self.f)(&self.state); Some(self.state.clone()) } #[inline] fn size_hint(&self) -> (usize, Option<usize>) { (std::usize::MAX, None) } } fn main() { let a = iterate(0, |x| x+1); println!("{:?}", a.iter().take(10).collect::<Vec<usize>>()); //~^ ERROR no method named `iter` found for type `Iterate<{integer} } </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. // #39665 #![feature(conservative_impl_trait)] fn batches(n: &u32) -> impl Iterator<Item=&u32> { std::iter::once(n) } fn main() {} </ins>

<ins> // Copyright 2017 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 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. trait VecN { const DIM: usize; } trait Mat { type Row: VecN; } fn m<M: Mat>() { let x = M::Row::DIM; } fn main() {} </ins>