result.txt

% go run -race test.go
==================
WARNING: DATA RACE
Write at 0x00c00009c000 by goroutine 7:
  main.main.func2()
      /Users/shibukawa/test.go:15 +0x7e

Previous write at 0x00c00009c000 by goroutine 6:
  main.main.func1()
      /Users/shibukawa/test.go:12 +0x7e

Goroutine 7 (running) created at:
  main.main()
      /Users/shibukawa/test.go:14 +0xfa

Goroutine 6 (finished) created at:
  main.main()
      /Users/shibukawa/test.go:11 +0xce
==================
Found 1 data race(s)
exit status 66

test.go

package main

import (
	"time"
)

func main() {
	var f bool
	a := make(map[int]bool)
	a[1] = true
	go func() {
		f = a[1]
	}()
	go func() {
		f = a[1]
	}()
	time.Sleep(time.Second)
}