let x = 0 ; x + 1.2
let x = false ; x + "false"
let x=0 ; let x=7
let x=[1, 2] ; x[7, 9]
let x = 0 ; x = 3.2
let x = 0 ; x = 7
let x=[1, 2] ; x[0] = 3.2
let x=[3, 4] ; x[0] = 7