How to generate coverage for a library with -C instrument-coverage

The documentation for Rust 1.60's new coverage option describes how to generate a coverage report for a binary, but is lacking an example for how to create coverage for a library that is tested via cargo test.

I started from the example provided in the Rust 1.60 announcement (which worked as described) and attempted to adapt that to a crate, but that didn't work.

The error occurs in this line: Adapt example to use a library. · scouten/rust-coverage-sandbox@065476e · GitHub

Can anybody who is familiar with these tools suggest a different invocation here?

Welp, I found a way through that, but the ergonomics of this part of cargo test are ... not wonderful.