The quick answer is still that you can use a UDL, as I said in 2022.

However, I had forgotten about this discussion, so I had started researching an answer to the ask-again Topic, and discovered that the SciTE testbed-editor will open Go/Golang (*.go) files and internally use the C++ lexer (LexCPP.cpp). The cpp.properties includes definitions for Go. So it can handle it.

I am going to point this out in the long-open ISSUE #8090 that Alan linked, because with that, there shouldn’t be much overhead to add it to Notepad++. So if anyone pays attention to my reply there, it might be that it’s much easier to add that language than was originally thought.

The UDL Collection does have a golang UDL available: https://github.com/notepad-plus-plus/userDefinedLanguages/blob/master/UDLs/go_byAnthonyStarks.xml

Download the raw XML into %AppData%\Notepad++\userDefineLangs\go_byAnthonyStarks.xml and restart Notepad++, and you will then have UDL-based syntax highlighting for golang on files whose extension are .go

Enjoy.

It’s an open ISSUE for Notepad++.