bad rustdoc ux: trait method implementations have their docstrings ommitted in the "implementors" section

[safinaskar]

I opened documentation of FromIterator ( https://doc.rust-lang.org/std/iter/trait.FromIterator.html ), then I scrolled to section "Implementors" and found this implementation:

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where
    V: FromIterator<A>,

This implementation was not documented on this page. I clicked "[src]" and was able to see docs in source. So, I thought that there is some bug in rustdoc, which causes this docs not to render. Then I opened page on Result ( https://doc.rust-lang.org/std/result/enum.Result.html ) and (susprisiongly) found that this impl is documented there! So, for unknown reasons rustdoc shows this doc on Result page, but doesn't show it on FromIterator page

[fmease]

This issue seems to have been fixed at some unknown point in time. It should be closed. (see comments below)

Result is now documented as an implementor on the FromIterator page.
For completeness, here is the link to the FromIterator impl on the Result page.

[safinaskar]

@fmease , I still don't see docs at link you provided. I mean I see implementation itself, but I don't see docs, i. e. I don't see text "Takes each element in the Iterator: if it is an Err, no further..."

My browser is Google Chrome 103.0.5060.53 on Debian Stretch

[fmease]

Oh my bad, I misread the issue.

The documentation Takes each element […] is not shown on the FromIterator page because it belongs to the method from_iter and not to the impl block and rustdoc doesn't display any associated items (like in this case from_iter) in a trait's Implementors section but only the “headers” of impl blocks (to save disk space and reduce render time I think).

All in all, this doesn't appear to be a rustdoc issue.
However, the question might still remain whether the doc comments should be moved from the method to the impl block. Not sure. The current location looks fine to me.

[safinaskar]

@fmease , thanks for explanation.

I think rustdoc should show full docs in implementors. Or at least provide a link to full docs. In current form this docs are too hard to find

[lolbinarycat]

clarifying this issue because it took me a bit to understand:

if you go to the "implementors" section on a trait page, you will simply get a list of impl items, along with any documentation that appears on the block itself:

if you go to the "trait implementations" section on a type page, you will get a collapsible list of impl blocks, including the contents of the impl block, such as documentation on method implemenations:

this inconsistency is confusing, since, for traits that have only a single method, implementors sometimes document details of their implementation on that method, and sometimes they do so on the impl block itself.