I don’t know how long this feature is in Visual Studio – maybe because I’m more keyboard-focused -, but I just noticed it and it’s a complete game changer. I mean, now I can’t imagine not having it. 😃
If you hover the mouse over a lambda or a local function the hint shows variables captured. This is so useful, especially if you’re in a performance sensitive code and you don’t want to create (or minimize creating) closures.
This works in my Visual Studio 2017 15.8.0 (latest at the time of writing) and 15.7.something (don’t remember exactly, because I updated that machine to 15.8.0 in the meantime).