Right, I completely see how that would prevent it from qualifying as a tail call, my misunderstanding was still different though. For some reason I thought that

Right, I completely see how that would prevent it from qualifying as a tail call, my misunderstanding was still different though. For some reason I thought that even if the recursive function was defined within the try-catch block (as below) it would prevent it from using a tail call: try let rec func ... = ... func( ... ) let result = func( ... ) with | ex -> ... I don't know exactly how I ended up thinking that, seems a bit silly in retrospect.