warning: value assigned to `x` is never read
 --> prog.rs:2:7
  |
2 |   let x = 5;
  |       ^
  |
  = note: `#[warn(unused_assignments)]` on by default
  = help: maybe it is overwritten before being read?

error[E0384]: cannot assign twice to immutable variable `x`
 --> prog.rs:3:3
  |
2 |   let x = 5;
  |       -
  |       |
  |       first assignment to `x`
  |       help: consider making this binding mutable: `mut x`
3 |   x = 10; // Error
  |   ^^^^^^ cannot assign twice to immutable variable

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0384`.