I'm basically trying to avoid situations where I might be legally obligated to prove a negative, that I did not take ideas or code from a proprietary yet source-available project that is topically very adjacent to some projects I work on. I write with Rust, use Rowan and tree-sitter crates, create LSP implementation, and so on.
I don't have a retained lawyer or legal budget, so it's just risk aversion on my part to treat this project as radioactive and never once look inside. Same reason a lot of folks don't look at GPL'd things.
The burden of proof is on the accuser so you never need to worry about proving a negative.
Unless there are patents involved, and we’re just talking about possible copyright infringement, then you’re free to borrow the ideas just not the expressions. Which in practice means if you’re not blatantly copying then the proof of Structure, Similarity and Organization is prohibitively expense for the plaintiff.
I don't have a retained lawyer or legal budget, so it's just risk aversion on my part to treat this project as radioactive and never once look inside. Same reason a lot of folks don't look at GPL'd things.