I'm somewhat confused about this because I've had gopls installed with vscode for years now, and as far back as I can remember, it always gave me a little yello

I'm somewhat confused about this because I've had gopls installed with vscode for years now, and as far back as I can remember, it always gave me a little yellow underlining warning when I had unused functions or unreachable blocks of code inside `if` or `switch-case` statements. It would seem to me that this has existed for a long time, or maybe it just builds on top of what was already there?