I'm trying to create a custom extension for a new language and find the regex flavors/options are not well documented in my opinion. I've found the same links to a github issue left on other SO questions, but all the discussion provides is that VS Code uses Rust engine for 'Find/Replace', not for extension language regex patterns/rules.
Is there any way to output the regex matches/errors in debug view when compiling a new extension? An ambiguous "invalid group" error message is not helpful to anyone for any situation. I've also found that the find/replace feature is not a good alternative either because the tmLanguage regex patterns allow some things the find/replace feature does not, plus it's a tiny box for long regexs.
I just want to see specific errors, if possible, and even more optimistically position / group specific errors