Map Immutability

Explain why the code below cannot compile and fix it. 

  1. package main
  3. type S struct {
  4.     name string
  5. }
  7. func main() {
  8.     m := map[string]S{"x": S{"one"}}
  9.     m["x"].name = "two"
  10. }

Answer

  2. package main
  4. type S struct {
  5.     name string
  6. }
  8. func main() {
  9.     m := map[string]*S{"x": &S{"one"}}
  10.     m["x"].name = "two"
  11. }
  13.