Avoid prefixing variables you will use with an underscore.

rust-underscore-idiom.rs

// Rust Idiom: 
// prefixing a variable with an underscore 
// signals to others that the variable 
// isn't going to be used, not that it is 
// intentionally private or an updated 
// variable.

main () {
  	let x = 12;
    // _x reads as 
    // "I don't care about this x but I want 
    //  to tell you it's x-like or from x"
    let _x = x + 1;
    dbg!(_x);
}