Rust/Variable/Shadowing

• you can use Rust/Variable/let on the same var more than once. Subsequent or nested use "shadows" prior use, following traditional scoping rules in c-family languages. Technically this is just a new binding.
• rust

   let x = 5;
   println!("Initial x: {x}"); // 5
   let x = x + 1; // Shadowing
   println!("Shadowed x: {x}"); // 6
   {
       let x = x * 2; // Shadowing in inner scope
       println!("Inner scope x: {x}"); // 8
   }
   println!("Outer scope x: {x}"); // 6

• The rules of shadowing also work with Rust/mut - but mutations, in this case can only happen in the scope in which they are (re-)defined.
  • rust

    let mut x = 20;
    println!("Initial x: {x}"); // 20
    {
        let mut x = x;
        x += 2;
    }
    println!("After mutation x: {x}"); // 20