[short] skip
# Reset all experiments so fieldtrack is definitely off.
env GOEXPERIMENT=none
go run m
stderr 'fieldtrack off'
# Turn fieldtrack on.
env GOEXPERIMENT=none,fieldtrack
go run m
stderr 'fieldtrack on'

-- ft_off.go --
// +build !goexperiment.fieldtrack

package main

func main() {
	println("fieldtrack off")
}

-- ft_on.go --
// +build goexperiment.fieldtrack

package main

func main() {
	println("fieldtrack on")
}

-- go.mod --
module m
go 1.14