Lint suggestion: Useless explicit documentation link

[ThomasdenH]

Once intra-rustdoc links lands, many explicit links will become unnecessary. It would be very useful to have a lint that would warn if the computed automatic link is the same as the provided link.

For example:

[Iterator](std::iter::Iterator)
Warning: unnecessary explicit rustdoc lint; you could replace this by "[Iterator]"

[sharksforarms]

Landed in 1.48: #43466

[sharksforarms]

Related: rust-lang/rust-clippy#1007

[jyn514]

This would be difficult to do in clippy because it needs access to resolve_str_path_error, which needs a resolver, which is destroyed when the TyCtxt is created. It would be much easier to implement in Rustdoc - that could be done by adding a check around here which sees if the link text resolves to the same item as the link target:

rust/src/librustdoc/passes/collect_intra_doc_links.rs

Line 917 in 25b7648

let link = self.resolve_link(&item, &doc, &self_name, parent_node, krate, md_link);

You'd also need to extend markdown_links to include the link text, right now it only includes the target:

rust/src/librustdoc/html/markdown.rs

Line 1265 in 25b7648

if let Event::Start(Tag::Link(kind, dest, _)) = ev.0 {

[jyn514]

@flip1995 can you move this to rust-lang/rust? It's still a good first issue, but it's not a good first issue for clippy.

[flip1995]

I don't have the rights to move this to rust-lang/rust, so @Manishearth

[mdsn]

@rustbot claim

[yerke]

@mdsn Are you still working on it?

[mdsn]

@yerke hi! No, please go right ahead and claim it. 😃 If you search for the issue number on Zulip you'll find some questions of mine back then. I'll try to post later some of what I thought while looking into this issue.