I think the best solution to this is when the language's syntax supports ORing cases together like this: let analyze_control_flow stmt = match stmt

I think the best solution to this is when the language's syntax supports ORing cases together like this: let analyze_control_flow stmt = match stmt with | If _ true_branch false_branch -> ... | While _ body -> .. | Assign _ _ | ExprStatement _ | Return -> ... So you still get to avoid repeating code, but all the variants are included visibly and the compiler can verify it.