Missing tooling in Rust?

Rust has excellent tooling, better than any other language I ever worked with. However occasionally I notice something is still missing or not as conveniently available as it could be.

This post is meant

• to help me and others discover that there are solutions in the Rust ecosystem we just don't know about
• as a list of project ideas for things to add to the ecosystem

I have noticed the following tools still seem to be missing:

A tool to find duplicate or copy/pasted code. Ideally one that can still detect duplicates if names are changed and whitespace and other inconsequential things (like trailing commas) are changed.

A Rust-specific search engine searching over as many Rust-specific documentation sites as possible (standard lib docs, docs.rs, the various books,...; maybe even some of the Rust-blogs too) and possibly even allowing a Hoogle-like search by type signature.

I am sure there are others. I know there is at least one more that I thought of this morning but can't recall right now.