JavaScript chiming in...

    function abc() {
       let a = 1
       {
         let b = 2
       }
       console.log(typeof a)      
       console.log(typeof b)
     }
     abc()

Used to do this occasionally for exactly the same reasons- don't leave dangling variables junking up your scope, and don't make weirdo functions with parameter passing that you'll only ever call once!