For Boolean conditionals, you're right. But there are richer conditionals that make certain variables available in only one clause of them, e.g., matching on wh

For Boolean conditionals, you're right. But there are richer conditionals that make certain variables available in only one clause of them, e.g., matching on whether an Either in Haskell is Left or Right, or whether a Result in Rust is an Err or an Ok.