Ivan Kochurkin

It's probably realted to #3360

Yes, something like `Semantics predicate at the beginning of the lexer rule significantly degradates performance`

Also, I suggest copying this info from the article to the ANTLR documentation.

You can also create a new topic in [ANTLR google group](https://groups.google.com/forum/#!forum/antlr-discussion)

Yes, I think it's a great idea!

I like GitHub issues, I think it's also an appropriate place for feature/bug discussions.

> Sorry for my absence, was really busy irl. Maybe it's even better because I significantly simplified runtime test infrastructure. Just compare test classes for C++ in the [old infrastructure](https://github.com/antlr/antlr4/tree/master/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp)...

Yes, it's here: https://github.com/antlr/antlr4/blob/dev/doc/creating-a-language-target.md Also, I'm in process of updating some outdated docs.

Also, I'd recommend looking at other targets and implementing a new one in the similar way. For instance, here is the setup for C++: https://github.com/antlr/antlr4/blob/dev/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/CppRunner.java

I don't think the BitSet implementation resolves all Go performance problems. But this issue is also too broad and maybe should be split into several small issues.