Nice giveaway, thank you for the generosity.

Is Gamedec still available? If so, I’d like to take it :)

I’m not sure how you intend to use this. When no variables are captured, the borrow checker will not have any issues with the closure method.

When you are still capturing, you could implement a macro like one answer suggests. However, IMO this highly depends on the complexity of the duplicated code and even then I don’t immediately see what the benefits compared to extracting it as a closure/function are.

This is entering subjective taste, but in my opinion this also is a feature of Rust. Especially when the closures are more complicated, it may be not as obvious if and where they are changing state (the fact that Rust implicitely mutably borrows the variables to the closures doesn’t help either).

So a solution of this issue for me would be to add the changed variables as parameters to the closures and explicitely mutably borrow them at the calls in the loop: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=78cc7947e2e0b07b54baf6e1a75a2632

I would agree with you that this increases code verbosity. However, this would be a price I’m willing to pay to help understand at quicker glances what happens inside this loop.