I was not aware of kcov or its basis bcov. Thanks for pointing those out.

However, a quick glance at the bcov source code leads me to believe that it only does source-line coverage, not branch coverage. So, unless my quick reading of bcov sources is mistaken, I couldn't test a Rust SQLite as well as I can test the existing SQLite because kcov/bcov is missing the ability to measure coverage of individual machine-code branch instructions, and the value I get from static analysis is much less than the value I get from branch-coverage testing tools.

That's not being pedantic, btw. The difference between source-line coverage and machine-code branch coverage is huge. The latter really is necessary.