Change:
<ins> // Copyright 2015 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. // @has manual_impl/trait.T.html // @has  - '//*[@class="docblock"]' 'Docs associated with the trait definition.' // @has  - '//*[@class="docblock"]' 'Docs associated with the trait a_method definition.' // @has  - '//*[@class="docblock"]' 'Docs associated with the trait b_method definition.' /// Docs associated with the trait definition. pub trait T { /// Docs associated with the trait a_method definition. fn a_method(&self) -> usize; /// Docs associated with the trait b_method definition. fn b_method(&self) -> usize { self.a_method() } } // @has manual_impl/struct.S1.html '//*[@class="trait"]' 'T' // @has  - '//*[@class="docblock"]' 'Docs associated with the S1 trait implementation.' // @has  - '//*[@class="docblock"]' 'Docs associated with the S1 trait a_method implementation.' // @!has - '//*[@class="docblock"]' 'Docs associated with the trait a_method definition.' // @!has - '//*[@class="docblock"]' 'Docs associated with the trait b_method definition.' pub struct S1(usize); /// Docs associated with the S1 trait implementation. impl T for S1 { /// Docs associated with the S1 trait a_method implementation. fn a_method(&self) -> usize { self.0 } } // @has manual_impl/struct.S2.html '//*[@class="trait"]' 'T' // @has  - '//*[@class="docblock"]' 'Docs associated with the S2 trait implementation.' // @has  - '//*[@class="docblock"]' 'Docs associated with the S2 trait a_method implementation.' // @has  - '//*[@class="docblock"]' 'Docs associated with the S2 trait b_method implementation.' // @!has - '//*[@class="docblock"]' 'Docs associated with the trait a_method definition.' // @!has - '//*[@class="docblock"]' 'Docs associated with the trait b_method definition.' pub struct S2(usize); /// Docs associated with the S2 trait implementation. impl T for S2 { /// Docs associated with the S2 trait a_method implementation. fn a_method(&self) -> usize { self.0 } /// Docs associated with the S2 trait b_method implementation. fn b_method(&self) -> usize { 5 } } // @has manual_impl/struct.S3.html '//*[@class="trait"]' 'T' // @has  - '//*[@class="docblock"]' 'Docs associated with the S3 trait implementation.' // @has  - '//*[@class="docblock"]' 'Docs associated with the S3 trait b_method implementation.' // @!has - '//*[@class="docblock"]' 'Docs associated with the trait a_method definition.' pub struct S3(usize); /// Docs associated with the S3 trait implementation. impl T for S3 { fn a_method(&self) -> usize { self.0 } /// Docs associated with the S3 trait b_method implementation. fn b_method(&self) -> usize { 5 } } </ins>

Discussion:
I use documentation on my trait impls to tell users about how my types behave: This documentation is not rendered anymore. I expect to see it under the entry for the implementation of the type. I think this was lost after (the otherwise very awesome!) documentation changes by
Note: Documentation on top of the item itself is properly rendered. If you too agree this is adequate, please close the issue again.
Just for reference: this also leaves the (perhaps not entirely obvious) operator impls on HashSets undocumented. Also see on this issue.
Yes, is dup of this. It is hiding stable parts of std from me: