Kronuz

Maybe xapian library just needs a little push from a larger community to make relicensing faster, Xapiand could help towards that end by helping brining in more people which can help. Xapiand source code is itself licensed as MIT (before compiling), and xapian community is already taking big steps towards relicensing.

There’s work in progress in a LSP fork at https://github.com/Kronuz/SublimeCodeIntel, it’ll have more plugins later, it currently has a few working.

Syntax highlighting, code completion, jump to definition and code linting, search and replace (regexps) in project... and of course a nice and, most importantly, fast code editor.

So, I use Sublime Text. Although it technically isn't an IDE, with some plugins installed (SublimeCodeIntel, SublimeLinter, and others), it works wonderfully as is if was. And it's blazing fast too.