How to enable code folding for redundant braces in C#?

I have a huge chunk of gross math inside a function. That math references a bunch of local variables declared before it, and creates a bunch of local variables. I want to put it into a local scope, but Rider won't let me fold that scope, it only suggests that I remove the redundant braces around it. How do I make it fold it?

(this should go without saying, but I don't want any style guide suggestions)