This is not a language issue at all, it's that the Rust regex library doesn't support lookaround, and some regexes in the adblocker use that feature. Yeah I ha

This is not a language issue at all, it's that the Rust regex library doesn't support lookaround, and some regexes in the adblocker use that feature. Yeah I had to web search what lookaround is. It means a zero-length conditional match in the expression. It's present in some but not all regex libraries.