It's not possible to search for specialized generics in docs

[mqudsi]

It should be possible to search for types implementing/using a particular specialization of a generic, as these specializations are already broken down and available either in the prototype/declaration (for parameters to and return values of functions) or in the "trait implementations" section (for specific trait implementations).

e.g. I should be able to search the rust docs for the literal string AsRef<[u8]> and get back any types implementing AsRef<[u8]>.

Some catches:

• Currently, the presence of a literal square bracket in the search term gives a query parser error:

  Query parser error: "Unexpected `[`".

• The default search type ("in names") will return traits, but not implementations of those traits. So we can expect there to always be zero results in the first/default search results tab,
• The remaining two tabs ("in parameters" and "in return types") cover some of the results (although the results are displayed for the type containing the function, not the function itself - but that's a different issue!) but trait implementations are not covered by either of these two tabs, meaning there needs to be a 4th tab (e.g. "in trait implementations") that sometimes appears depending on the search type.

@rustbot label +A-docs -C-bug +C-feature-request

[GuillaumeGomez]

Simply remove the []. You can search for AsRef<u8>, it'll pick the [u8] too.

[mqudsi]

Do [ and ] have special meaning to the search right now such that they can't be treated as literals?

[GuillaumeGomez]

They don't have any meaning.

[mqudsi]

I'm not sure if you want to discuss the other points in this issue or in a new issue, but the search results aren't really illuminating for trait implementations. The search for AsRef<u8> in the current nightly docs returns the following:

The first result (std::convert::AsRef) contains a trait implementation for AsRef<[u8]> (but not AsRef<u8> which is what I literally searched - just a note!) but the results overview isn't very illuminating. The results are mainly only for the AsRef trait itself, and don't showcase my search terms, and the results exclude types implementing the trait (I can get to primitive.str via AsRef thanks to cross-linking, but the search results themselves don't provide any context).

It would be nice if searching for a trait or a specialization of a trait also included (as another tab or via something else?) types that implemented that trait/specialization. It would also be really helpful if some sort of context could be shown in the results so that one doesn't have to then ctrl-f for the search terms after clicking on a result to see if it's what they actually want or not before going back to the search results list and trying another result.

I don't know if I'm approaching this the right way or if it's better for me to come up with some sort of concrete proposal for how I personally think the search results could show more context/be more immediately useful at a glance and don't mean to disparage any of the work that's already been put into the (excellent!) rustdocs already.