cargo-expand VS cargo-llvm-cov

It's been superseded by https://github.com/dtolnay/cargo-expand

Try installing cargo expand, it's useful to see how macros eventually get expanded. For example, if you run cargo expand on the following code

You can use cargo expand to see what your code expands to: https://github.com/dtolnay/cargo-expand

Not too familiar with macros but does cargo-expand do what you want or did you mean something else?

Yes. You can use Tools > Expand Macro on the playground or install and run cargo-expand to see what the macro expands to. It just adds a & before the argument.

cargo expand

Along with what others are saying, there is also cargo expand which can show you what code a macro generates

Something that may help you understand code with magic proc macros is this utility. It's basically a wrapper around a Rust compiler flag that allows you to expand macros for a file.

You can use https://github.com/dtolnay/cargo-expand to examine how it works.

I'll let them speak for themselves: https://github.com/taiki-e/cargo-llvm-cov https://nexte.st/index.html

Meanwhile I wholeheartedly recommend https://github.com/taiki-e/cargo-llvm-cov which makes it almost as simple.

And the options to fail on insufficient coverage are rather lacking supporting only line coverage. I have suggested improvement and might do it if there is interest from the author.

Another alternative is https://github.com/taiki-e/cargo-llvm-cov which is easy to use. Don't forget to also try the --html flag with it.

I'd take a look at either https://github.com/taiki-e/cargo-llvm-cov and/or https://github.com/dtolnay/cargo-expand for this kinda of behavior.