src/librustc_error_codes/error_codes/E0384.md

   1 An immutable variable was reassigned.
   2
   3 Erroneous code example:
   4
   5 ```compile_fail,E0384
   6 fn main() {
   7     let x = 3;
   8     x = 5; // error, reassignment of immutable variable
   9 }
  10 ```
  11
  12 By default, variables in Rust are immutable. To fix this error, add the keyword
  13 `mut` after the keyword `let` when declaring the variable. For example:
  14
  15 ```
  16 fn main() {
  17     let mut x = 3;
  18     x = 5;
  19 }
  20 ```