1package main 2 3type T struct { 4 m map[int]int 5} 6 7func main() { 8 t := T{ 9 m: make(map[int]int), 10 } 11 t.Inc(5) 12 t.Inc(7) 13} 14 15func (s *T) Inc(key int) { 16 v := s.m[key] // break, line 16 17 v++ 18 s.m[key] = v // also here 19} 20